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Sample records for hydrogen atmosphere issledovanie

  1. An archetype hydrogen atmosphere problem

    NASA Technical Reports Server (NTRS)

    Athay, R. G.; Mihalas, D.; Shine, R. A.

    1975-01-01

    Populations for the first three bound states and the continuum of hydrogen are determined for an isothermal hydrostatic atmosphere at 20,000 K. The atmosphere is treated as optically thin in the Balmer and Paschen continua and illuminated by continuum radiation at these wavelengths with prescribed radiation temperatures. The atmosphere is optically thick in the 2-1, 3-1, 3-2 and c-1 transitions. Three stages of approximation are treated: (1) radiative detailed balance in the 2-1, 3-1 and 3-2 transitions, (2) radiative detailed balance in the 3-1 and 3-2 transitions, and (3) all transitions out of detailed balance. The solution of this problem is nontrivial and presents sufficient difficulty to have caused the failure of at least one rather standard technique. The problem is thus a good archetype against which new methods or new implementations of old methods may be tested.

  2. A hydrogen-rich early Earth atmosphere.

    PubMed

    Tian, Feng; Toon, Owen B; Pavlov, Alexander A; De Sterck, H

    2005-05-13

    We show that the escape of hydrogen from early Earth's atmosphere likely occurred at rates slower by two orders of magnitude than previously thought. The balance between slow hydrogen escape and volcanic outgassing could have maintained a hydrogen mixing ratio of more than 30%. The production of prebiotic organic compounds in such an atmosphere would have been more efficient than either exogenous delivery or synthesis in hydrothermal systems. The organic soup in the oceans and ponds on early Earth would have been a more favorable place for the origin of life than previously thought.

  3. Isotopic composition of atmospheric hydrogen and methane

    USGS Publications Warehouse

    Bainbridge, A.E.; Suess, H.E.; Friedman, I.

    1961-01-01

    IN a recent communication, Bishop and Taylor1 express the opinion that the tritium concentration of free hydrogen in the atmosphere has been rising over the past ten years, with a doubling time of approximately 18 months. The authors suspect that artificial tritium was released into the atmosphere several years before the Castle test series in 1954, which is commonly assumed to have led to the first pronounced rise in the tritium concentration of terrestrial surface water. Bishop and Taylor's communication includes a diagram of the logarithms of all the experimentally determined tritium values in free atmospheric hydrogen plotted against time. The plot shows that the values follow a straight line that includes the first value obtained by Faltings and Harteck2 on atmospheric hydrogen collected in 1948. ?? 1961 Nature Publishing Group.

  4. Atomic hydrogen distribution. [in Titan atmospheric model

    NASA Technical Reports Server (NTRS)

    Tabarie, N.

    1974-01-01

    Several possible H2 vertical distributions in Titan's atmosphere are considered with the constraint of 5 km-A a total quantity. Approximative calculations show that hydrogen distribution is quite sensitive to two other parameters of Titan's atmosphere: the temperature and the presence of other constituents. The escape fluxes of H and H2 are also estimated as well as the consequent distributions trapped in the Saturnian system.

  5. Atmospheric Hydrogen Scavenging: from Enzymes to Ecosystems

    PubMed Central

    Constant, Philippe; Hards, Kiel; Morales, Sergio E.; Oakeshott, John G.; Russell, Robyn J.; Taylor, Matthew C.; Berney, Michael; Conrad, Ralf; Cook, Gregory M.

    2014-01-01

    We have known for 40 years that soils can consume the trace amounts of molecular hydrogen (H2) found in the Earth's atmosphere. This process is predicted to be the most significant term in the global hydrogen cycle. However, the organisms and enzymes responsible for this process were only recently identified. Pure culture experiments demonstrated that several species of Actinobacteria, including streptomycetes and mycobacteria, can couple the oxidation of atmospheric H2 to the reduction of ambient O2. A combination of genetic, biochemical, and phenotypic studies suggest that these organisms primarily use this fuel source to sustain electron input into the respiratory chain during energy starvation. This process is mediated by a specialized enzyme, the group 5 [NiFe]-hydrogenase, which is unusual for its high affinity, oxygen insensitivity, and thermostability. Atmospheric hydrogen scavenging is a particularly dependable mode of energy generation, given both the ubiquity of the substrate and the stress tolerance of its catalyst. This minireview summarizes the recent progress in understanding how and why certain organisms scavenge atmospheric H2. In addition, it provides insight into the wider significance of hydrogen scavenging in global H2 cycling and soil microbial ecology. PMID:25501483

  6. Photosynthesis in Hydrogen-Dominated Atmospheres

    PubMed Central

    Bains, William; Seager, Sara; Zsom, Andras

    2014-01-01

    The diversity of extrasolar planets discovered in the last decade shows that we should not be constrained to look for life in environments similar to early or present-day Earth. Super-Earth exoplanets are being discovered with increasing frequency, and some will be able to retain a stable, hydrogen-dominated atmosphere. We explore the possibilities for photosynthesis on a rocky planet with a thin H2-dominated atmosphere. If a rocky, H2-dominated planet harbors life, then that life is likely to convert atmospheric carbon into methane. Outgassing may also build an atmosphere in which methane is the principal carbon species. We describe the possible chemical routes for photosynthesis starting from methane and show that less energy and lower energy photons could drive CH4-based photosynthesis as compared with CO2-based photosynthesis. We find that a by-product biosignature gas is likely to be H2, which is not distinct from the hydrogen already present in the environment. Ammonia is a potential biosignature gas of hydrogenic photosynthesis that is unlikely to be generated abiologically. We suggest that the evolution of methane-based photosynthesis is at least as likely as the evolution of anoxygenic photosynthesis on Earth and may support the evolution of complex life. PMID:25411926

  7. Photosynthesis in hydrogen-dominated atmospheres.

    PubMed

    Bains, William; Seager, Sara; Zsom, Andras

    2014-11-18

    The diversity of extrasolar planets discovered in the last decade shows that we should not be constrained to look for life in environments similar to early or present-day Earth. Super-Earth exoplanets are being discovered with increasing frequency, and some will be able to retain a stable, hydrogen-dominated atmosphere. We explore the possibilities for photosynthesis on a rocky planet with a thin H2-dominated atmosphere. If a rocky, H2-dominated planet harbors life, then that life is likely to convert atmospheric carbon into methane. Outgassing may also build an atmosphere in which methane is the principal carbon species. We describe the possible chemical routes for photosynthesis starting from methane and show that less energy and lower energy photons could drive CH4-based photosynthesis as compared with CO2-based photosynthesis. We find that a by-product biosignature gas is likely to be H2, which is not distinct from the hydrogen already present in the environment. Ammonia is a potential biosignature gas of hydrogenic photosynthesis that is unlikely to be generated abiologically. We suggest that the evolution of methane-based photosynthesis is at least as likely as the evolution of anoxygenic photosynthesis on Earth and may support the evolution of complex life.

  8. Hydrogen peroxide measurements in the marine atmosphere

    NASA Astrophysics Data System (ADS)

    Jacob, P.; Klockow, D.

    1992-11-01

    Hydrogen peroxide, one of the key compounds in multiphase atmospheric chemistry, was measured on an Atlantic cruise (ANT VII/1) of the German research vessel Polarstern from 15 September to 9 October 1988, in rain and ambient air by a chemiluminescence technique. For gas-phase H2O2 cryogenic sampling was employed. The presented results show an increase of gas-phase mixing ratios of about 45 pptv per degree latitude between 50 deg N and 0 deg, and a maximum of 3.5 ppbv around the equator. Generally higher mixing ratios were observed in the Southern Hemisphere, with a clear diurnal variation. The H2O2 mixing ratio is correlated to the UV radiation intensity and to the temperature difference between air and ocean surface water.

  9. Innovative Monitoring of Atmospheric Gaseous Hydrogen Fluoride

    PubMed Central

    Bonari, Alessandro; Pompilio, Ilenia; Monti, Alessandro; Arcangeli, Giulio

    2016-01-01

    Hydrogen fluoride (HF) is a basic raw material for a wide variety of industrial products, with a worldwide production capacity of more than three million metric tonnes. A novel method for determining particulate fluoride and gaseous hydrogen fluoride in air is presented herewith. Air was sampled using miniaturised 13 mm Swinnex two-stage filter holders in a medium-flow pumping system and through the absorption of particulate fluoride and HF vapours on cellulose ester filters uncoated or impregnated with sodium carbonate. Furthermore, filter desorption from the holders and the extraction of the pentafluorobenzyl ester derivative based on solid-phase microextraction were performed using an innovative robotic system installed on an xyz autosampler on-line with gas chromatography (GC)/mass spectrometry (MS). After generating atmospheres of a known concentration of gaseous HF, we evaluated the agreement between the results of our sampling method and those of the conventional preassembled 37 mm cassette (±8.10%; correlation coefficient: 0.90). In addition, precision (relative standard deviation for n = 10, 4.3%), sensitivity (0.2 μg/filter), and linearity (2.0–4000 μg/filter; correlation coefficient: 0.9913) were also evaluated. This procedure combines the efficiency of GC/MS systems with the high throughput (96 samples/day) and the quantitative accuracy of pentafluorobenzyl bromide on-sample derivatisation. PMID:27829835

  10. Comment on "A hydrogen-rich early Earth atmosphere".

    PubMed

    Catling, David C

    2006-01-06

    Tian et al. (Reports, 13 May 2005, p. 1014) proposed a hydrogen-rich early atmosphere with slow hydrogen escape from a cold thermosphere. However, their model neglects the ultraviolet absorption of all gases other than H2. The model also neglects Earth's magnetic field, which affects the temperature and density of ions and promotes nonthermal escape of neutral hydrogen.

  11. The potential impact of hydrogen energy use on the atmosphere

    NASA Astrophysics Data System (ADS)

    van Ruijven, B. J.; Lamarque, J. F.; van Vuuren, D. P.; Kram, T.; Eerens, H.

    2009-04-01

    Energy models show very different trajectories for future energy systems (partly as function of future climate policy). One possible option is a transition towards a hydrogen-based energy system. The potential impact of such hydrogen economy on atmospheric emissions is highly uncertain. On the one hand, application of hydrogen in clean fuel cells reduces emissions of local air pollutants, like SOx and NOx. On the other hand, emissions of hydrogen from system leakages are expected to change the atmospheric concentrations and behaviour (see also Price et al., 2007; Sanderson et al., 2003; Schultz et al., 2003; Tromp et al., 2003). The uncertainty arises from several sources: the expected use of hydrogen, the intensity of leakages and emissions, and the atmospheric chemical behaviour of hydrogen. Existing studies to the potential impacts of a hydrogen economy on the atmosphere mostly use hydrogen emission scenarios that are based on simple assumptions. This research combines two different modelling efforts to explore the range of impacts of hydrogen on atmospheric chemistry. First, the potential role of hydrogen in the global energy system and the related emissions of hydrogen and other air pollutants are derived from the global energy system simulation model TIMER (van Vuuren, 2007). A set of dedicated scenarios on hydrogen technology development explores the most pessimistic and optimistic cases for hydrogen deployment (van Ruijven et al., 2008; van Ruijven et al., 2007). These scenarios are combined with different assumptions on hydrogen emission factors. Second, the emissions from the TIMER model are linked to the NCAR atmospheric model (Lamarque et al., 2005; Lamarque et al., 2008), in order to determine the impacts on atmospheric chemistry. By combining an energy system model and an atmospheric model, we are able to consistently explore the boundaries of both hydrogen use, emissions and impacts on atmospheric chemistry. References: Lamarque, J.-F., Kiehl, J. T

  12. Hydrogen in biogas and its impact to the atmosphere

    NASA Astrophysics Data System (ADS)

    Walter, S.; Laukenmann, S.; Stams, A. J. M.; Röckmann, T.

    2009-04-01

    The shortage and increase in cost of fossil fuels leads to an increased interest in renewable energy sources. One important renewable energy source is biogas, produced by fermentation of organic material. During the last ten years the number of biogas plants has continuously increased and it is expected to increase further. Biogas is a mixture of mainly methane and carbon dioxide but contains also molecular hydrogen (H2). The hydrogen content of biogas depends on the used substrate and the production process. Hydrogen is also produced by conversion of biogas. Although hydrogen is considered as one of the most important future energy carriers, little is known about the global biogeochemical cycle of this trace gas (Rhee et al. 2006) and its impact to the atmosphere is discussed controversially. In order to assess the impact of an expected increasing H2 concentration to the atmosphere a fundamental understanding of the sources and sinks of the global H2 cycle is indispensable (Tromp et al. 2003, Warwick et al. 2004). Due to the large mass difference between hydrogen and deuterium the isotope composition is one possibility to obtain further information about the sources and sinks. Here we will present first results of the isotope composition of hydrogen in biogas. Literature Rhee, T.S., C.A.M. Brenninkmeijer, and T. Röckmann; The overwhelming role of soils in the global atmospheric hydrogen cycle, Atmos. Chem. Phys., 6, 1611-1625, 2006. Tromp, T.K., Shi, R.-L., Allen, M., Eiler, J.M., and Y. L. Yung1; Potential Environmental Impact of a Hydrogen Economy on the Stratosphere, Science, 300, 1740-1742, 2003. Warwick, N.J., Bekki, S., Nisbet, E.G., and J.A. Pyle; Impact of a hydrogen economy on the stratosphere and troposphere studied in a 2-D model; Geo.Res.Lett., 31, L05107, doi:10.1029/2003GL019224, 2004.

  13. Hydrogen Bonding Interaction between Atmospheric Gaseous Amides and Methanol

    PubMed Central

    Zhao, Hailiang; Tang, Shanshan; Xu, Xiang; Du, Lin

    2016-01-01

    Amides are important atmospheric organic–nitrogen compounds. Hydrogen bonded complexes of methanol (MeOH) with amides (formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide and N,N-dimethylacetamide) have been investigated. The carbonyl oxygen of the amides behaves as a hydrogen bond acceptor and the NH group of the amides acts as a hydrogen bond donor. The dominant hydrogen bonding interaction occurs between the carbonyl oxygen and the OH group of methanol as well as the interaction between the NH group of amides and the oxygen of methanol. However, the hydrogen bonds between the CH group and the carbonyl oxygen or the oxygen of methanol are also important for the overall stability of the complexes. Comparable red shifts of the C=O, NH- and OH-stretching transitions were found in these MeOH–amide complexes with considerable intensity enhancement. Topological analysis shows that the electron density at the bond critical points of the complexes fall in the range of hydrogen bonding criteria, and the Laplacian of charge density of the O–H∙∙∙O hydrogen bond slightly exceeds the upper value of the Laplacian criteria. The energy decomposition analysis further suggests that the hydrogen bonding interaction energies can be mainly attributed to the electrostatic, exchange and dispersion components. PMID:28042825

  14. Hydrogen-atmosphere induction furnace has increased temperature range

    NASA Technical Reports Server (NTRS)

    Caves, R. M.; Gresslin, C. H.

    1966-01-01

    Improved hydrogen-atmosphere induction furnace operates at temperatures up to 5,350 deg F. The furnace heats up from room temperature to 4,750 deg F in 30 seconds and cools down to room temperature in 2 minutes.

  15. (abstract) Odd Hydrogen in the Atmospheres of Earth and Mars

    NASA Technical Reports Server (NTRS)

    Nair, Hari; Allen, Mark; Yung, Yuk L.

    1994-01-01

    The Martian atmosphere has many features in common with the terrestrial mesosphere. Both share similar pressure and temperature ranges, and much of the same chemistry operates in each. For example, the radical species H, OH, and H(sub 2)O, which comprise the odd hydrogen family, are of central importance in the catalytic destruction of CO and O(sub 3) in both atmospheres. The inclusion of recent chemical kinetics data, specifically temperature dependent CO(sub 2) absorption cross-sections, into our one dimensional photochemical model of the Martial atmosphere shows that oxidation of CO by odd hydrogen is too efficient. The incorporation of smaller cross sections for CO(sub 2) leads to an enhanced photolysis rate of water vapor, increasing odd hydrogen to the point where the predicted mixing ratio of CO in our model is substantially less than the observed value of 6.5 x 10(sup -4). Interestingly, most photochemical models of the terrestrial mesosphere underestimate the CO and O(sub 3) densities using currently accepted photodissociation and kinetic rate coefficients. This has also been attributed to an overabundance of odd hydrogen in the models. We shall show that agreement between models and observations of CO in the Martian atmosphere as well as of CO and O(sub 3) in the terrestrial mesosphere can be achieved by revising the rate constants for the reactions OH + HO(sub 2) and CO + OH within their published uncertainties. The fact that similar revisions alleviate discrepancies in both the terrestrial and Martian atmospheres warrants a re-evaluation of these key rate constants at the appropriate temperatures and pressures.

  16. Ultraviolet absorption spectrum of hydrogen peroxide vapor. [for atmospheric abundances

    NASA Technical Reports Server (NTRS)

    Molina, L. T.; Schinke, S. D.; Molina, M. J.

    1977-01-01

    The ultraviolet absorption cross sections of hydrogen peroxide vapor have been determined over the wavelength range 210 to 350 nm at 296 K. At the longer wavelengths, the gas phase absorptivities are significantly larger than the corresponding values in condensed phase. The atmospheric H2O2 photodissociation rate for overhead sun at the earth's surface is estimated to be about 1.3 x 10 to the -5th/sec.

  17. Raman Scattering by Molecular Hydrogen and Nitrogen in Exoplanetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Oklopčić, Antonija; Hirata, Christopher M.; Heng, Kevin

    2016-11-01

    An important source of opacity in exoplanet atmospheres at short visible and near-UV wavelengths is Rayleigh scattering of light on molecules. It is accompanied by a related, albeit weaker process—Raman scattering. We analyze the signatures of Raman scattering imprinted in the reflected light and the geometric albedo of exoplanets, which could provide information about atmospheric properties. Raman scattering affects the geometric albedo spectra of planets in the following ways. First, it causes filling-in of strong absorption lines in the incident radiation, thus producing sharp peaks in the albedo. Second, it shifts the wavelengths of spectral features in the reflected light causing the so-called Raman ghost lines. Raman scattering can also cause a broadband reduction of the albedo due to wavelength shifting of a stellar spectrum with red spectral index. Observing the Raman peaks in the albedo could be used to measure the column density of gas, thus providing constraints on the presence of clouds in the atmosphere. Observing the Raman ghost lines could be used to spectroscopically identify the main scatterer in the atmosphere, even molecules like H2 or N2, which do not have prominent spectral signatures in the optical wavelength range. If detected, ghost lines could also provide information about the temperature of the atmosphere. In this paper, we investigate the effects of Raman scattering in hydrogen- and nitrogen-dominated atmospheres. We analyze the feasibility of detecting the signatures of Raman scattering with the existing and future observational facilities, and of using these signatures as probes of exoplanetary atmospheres.

  18. Photoheating efficiency for hydrogen-dominated atmospheres of exoplanets

    NASA Astrophysics Data System (ADS)

    Shematovich, V. I.

    2013-09-01

    space distribution of the neutral atmospheres. Outputs of the model are: (i) energy deposition rates and heating efficiencies; (ii) collision-induced optical emissions; (iii) photochemistry and transport of excited and hot species [6]. In the numerical simulations the evolution of the system of modeling particles (representing photoelectrons) due to collisional processes and particle transport is calculated from the initial to the steady state [5] and the space distribution of the energy spectra of photoelectrons are estimated. The relative importance of the collisional processes is governed by their cross sections. Photo- and photoelectron impact heating of the H2/He/H atmosphere was calculated for the upper atmosphere model [1] of the planet HD209458b and the XUV stellar spectrum approximated by the quit Sun conditions. It was found that photoheating efficiency is a height dependent and varies in the range 40 ÷ 60%. The relative inputs of the soft X rays and EUV radiation were estimated. Calculations showed that energy deposition rate of the stellar XUV radiation in the H2/He/H atmosphere and the photoheating efficiency are strongly dependent on (i) the composition of the neutral atmosphere, and (ii) the energy spectrum of the stellar XUV radiation. Both characteristics are height-dependent ones. The model is critically dependent on the relevant data on the stellar XUV flux and the atomic and molecular data on photoabsorption and electron impact cross sections. Detailed kinetics of the photoelectrons and the calculated height profiles of the photoheating efficiency can be used in the aeronomic models of the hydrogen-dominant atmospheres of the Solar System giant planets and of hot Jupiters and super-Earths.

  19. Hydrogen emission from Jupiter: Hydrogen emission from sunlit atmosphere of Saturn

    NASA Technical Reports Server (NTRS)

    Shemansky, D. E.; Holberg, J. B.

    1987-01-01

    Successful IUE observations of the equatorial sunlit atmosphere of Jupiter and Saturn have been obtained. Spectra containing atomic and molecular hydrogen and solar reflection continuum emissions have been analyzed, with the purpose of determining the long term temporal behavior of the electroglow process. Quantitative estimates have been established for the first time using a model analysis of the short wavelength region of the spectrum. Both systems show varying degrees of long term variability in hydrogen emission rate, but the time scale is too short to determine whether there is a dependence on solar cycle activity. As part of the emission modeling program, a preliminary point source spreading function for the IUE SWP instrument has been established, suggesting a wavelength dependence in spectral line width different from previous analyses. Further IUE observations are planned for both Jupiter and Saturn.

  20. Seismology of a Massive Pulsating Hydrogen Atmosphere White Dwarf

    NASA Astrophysics Data System (ADS)

    Kepler, S. O.; Pelisoli, Ingrid; Peçanha, Viviane; Costa, J. E. S.; Fraga, Luciano; Hermes, J. J.; Winget, D. E.; Castanheira, Barbara; Córsico, A. H.; Romero, A. D.; Althaus, Leandro; Kleinman, S. J.; Nitta, A.; Koester, D.; Külebi, Baybars; Jordan, Stefan; Kanaan, Antonio

    2012-10-01

    We report our observations of the new pulsating hydrogen atmosphere white dwarf SDSS J132350.28+010304.22. We discovered periodic photometric variations in frequency and amplitude that are commensurate with nonradial g-mode pulsations in ZZ Ceti stars. This, along with estimates for the star's temperature and gravity, establishes it as a massive ZZ Ceti star. We used time-series photometric observations with the 4.1 m SOAR Telescope, complemented by contemporary McDonald Observatory 2.1 m data, to discover the photometric variability. The light curve of SDSS J132350.28+010304.22 shows at least nine detectable frequencies. We used these frequencies to make an asteroseismic determination of the total mass and effective temperature of the star: M sstarf = 0.88 ± 0.02 M ⊙ and T eff = 12, 100 ± 140 K. These values are consistent with those derived from the optical spectra and photometric colors.

  1. SEISMOLOGY OF A MASSIVE PULSATING HYDROGEN ATMOSPHERE WHITE DWARF

    SciTech Connect

    Kepler, S. O.; Pelisoli, Ingrid; Pecanha, Viviane; Costa, J. E. S.; Fraga, Luciano; Hermes, J. J.; Winget, D. E.; Castanheira, Barbara; Corsico, A. H.; Romero, A. D.; Althaus, Leandro; Kleinman, S. J.; Nitta, A.; Koester, D.; Kuelebi, Baybars; Kanaan, Antonio

    2012-10-01

    We report our observations of the new pulsating hydrogen atmosphere white dwarf SDSS J132350.28+010304.22. We discovered periodic photometric variations in frequency and amplitude that are commensurate with nonradial g-mode pulsations in ZZ Ceti stars. This, along with estimates for the star's temperature and gravity, establishes it as a massive ZZ Ceti star. We used time-series photometric observations with the 4.1 m SOAR Telescope, complemented by contemporary McDonald Observatory 2.1 m data, to discover the photometric variability. The light curve of SDSS J132350.28+010304.22 shows at least nine detectable frequencies. We used these frequencies to make an asteroseismic determination of the total mass and effective temperature of the star: M{sub *} = 0.88 {+-} 0.02 M{sub Sun} and T{sub eff} = 12, 100 {+-} 140 K. These values are consistent with those derived from the optical spectra and photometric colors.

  2. A nitrogen pressure of 50 atmospheres does not prevent evolution of hydrogen by nitrogenase.

    PubMed

    Simpson, F B; Burris, R H

    1984-06-08

    The effect of a partial pressure of nitrogen of 50 atmospheres (5065 kilopascals ) on the hydrogen evolution reaction of nitrogenase has been investigated. Evolution of hydrogen was not blocked completely by 50 atmospheres of nitrogen in any of four experiments; rather, 27.3 +/- 2.4 percent of the total electron flux through nitrogenase was directed toward production of hydrogen. The ratio of hydrogen evolved to nitrogen fixed was close to 1:1, which implies that hydrogen evolution is obligatory in the fixation of molecular nitrogen by nitrogenase.

  3. Deprotonated Dicarboxylic Acid Homodimers: Hydrogen Bonds and Atmospheric Implications

    SciTech Connect

    Hou, Gao-Lei; Valiev, Marat; Wang, Xue-Bin

    2016-03-31

    Dicarboxylic acids represent an important class of water-soluble organic compounds found in the atmosphere. In this work we are studying properties of dicarboxylic acid homodimer complexes (HO2(CH2)nCO2-[HO2(CH2)nCO2H], n = 0-12), as potentially important intermediates in aerosol formation processes. Our approach is based on experimental data from negative ion photoelectron spectra of the dimer complexes combined with updated measurements of the corresponding monomer species. These results are analyzed with quantum-mechanical calculations, which provide further information about equilibrium structures, thermochemical parameters associated with the complex formation, and evaporation rates. We find that upon formation of the dimer complexes the electron binding energies increase by 1.3–1.7 eV (30.0–39.2 kcal/mol), indicating increased stability of the dimerized complexes. Calculations indicate that these dimer complexes are characterized by the presence of strong intermolecular hydrogen bonds with high binding energies and are thermodynamically favorable to form with low evaporation rates. Comparison with previously studied HSO4-[HO2(CH2)2CO2H] complex (J. Phys. Chem. Lett. 2013, 4, 779-785) shows that HO2(CH2)2CO2-[HO2(CH2)2CO2H] has very similar thermochemical properties. These results imply that dicarboxylic acids not only can contribute to the heterogeneous complexes formation involving sulfuric acid and dicarboxylic acids, but also can promote the formation of homogenous complexes by involving dicarboxylic acids themselves.

  4. Hot hydrogen and oxygen atoms in the upper atmospheres of Venus and Mars

    NASA Technical Reports Server (NTRS)

    Nagy, Andrew F.; Kim, Jhoon; Cravens, Thomas E.

    1990-01-01

    Optical observations of hot atoms in the atmospheres of Venus and Mars are briefly reviewed. A summary of hot hydrogen and oxygen production and loss processes is given. Results of some recent model calculations as well as a number of new results of the hot hydrogen and oxygen populations are presented and their implication in terms of solar wind interaction processes is discussed.

  5. Hydrogen-water vapor mixtures: Control of hydrothermal atmospheres by hydrogen osmosis

    USGS Publications Warehouse

    Shaw, H.R.

    1963-01-01

    Experiments at 700??C and 800 bars total pressure demonstrate positive deviations from ideality for mixtures of hydrogen and H2O gases. The deviations are greater than predicted with Stockmayer's method. The composition of the mixture and the fugacity of hydrogen are controlled by diffusing hydrogen through metallic membranes. The results give the fugacities of both H 2O and oxygen.

  6. Hydrogen-deficient atmospheres for cool carbon stars

    NASA Technical Reports Server (NTRS)

    Johnson, H. R.; Bower, C. D.; Lemke, D. A.; Luttermoser, D. G.; Petrakis, J. P.; Reinhart, M. D.; Welch, K. A.; Alexander, D. R.; Goebel, J. H.

    1985-01-01

    Motivated by recent work which hints at a possible deficiency of hydrogen in non-Mira N-type carbon stars and to further explore the parameter space of chemical composition, computations have been made of a series of hydrogen-deficient models for carbon stars. For these models Teff = 3000 K, and log g = 0.0. Solar abundances are used for all elements except for carbon (which is enhanced to give C/O = 1.05), hydrogen, and helium. As the fractional abundance of hydrogen is decreased, being replaced by helium, the temperature-optical depth relation is affected only slightly, but the temperature-pressure relation is changed. The most striking change in the emergent flux is the decrease of the H(-) peak at 1.65 micron compared with the blackbody peak at 1.00 micron.

  7. Ignition during hydrogen release from high pressure into the atmosphere

    NASA Astrophysics Data System (ADS)

    Oleszczak, P.; Wolanski, P.

    2010-12-01

    The first investigations concerned with a problem of hydrogen jet ignition, during outflow from a high-pressure vessel were carried out nearly 40 years ago by Wolanski and Wojcicki. The research resulted from a dramatic accident in the Chorzow Chemical Plant Azoty, where the explosion of a synthesis gas made up of a mixture composed of three moles of hydrogen per mole of nitrogen, at 300°C and 30 MPa killed four people. Initial investigation had excluded potential external ignition sources and the main aim of the research was to determine the cause of ignition. Hydrogen is currently considered as a potential fuel for various vehicles such as cars, trucks, buses, etc. Crucial safety issues are of potential concern, associated with the storage of hydrogen at a very high pressure. Indeed, the evidence obtained nearly 40 years ago shows that sudden rupture of a high-pressure hydrogen storage tank or other component can result in ignition and potentially explosion. The aim of the present research is identification of the conditions under which hydrogen ignition occurs as a result of compression and heating of the air by the shock wave generated by discharge of high-pressure hydrogen. Experiments have been conducted using a facility constructed in the Combustion Laboratory of the Institute of Heat Engineering, Warsaw University of Technology. Tests under various configurations have been performed to determine critical conditions for occurrence of high-pressure hydrogen ignition. The results show that a critical pressure exists, leading to ignition, which depends mainly on the geometric configuration of the outflow system, such as tube diameter, and on the presence of obstacles.

  8. The Effect of Atmospheric Hydrogen on the Albedo and Surface Temperature of Mars

    NASA Astrophysics Data System (ADS)

    Wallack, Nicole Lisa; Kaltenegger, Lisa; Ramirez, Ramses

    2016-01-01

    The presence of hydrogen in planetary atmospheres has been shown to have the potential to dramatically effect the temperatures of planets. The collision-induced absorption (CIA) of hydrogen with carbon dioxide or nitrogen has been shown to have a substantial effect on the atmospheric temperature and albedo of a planet, possibly to the point at which life could exist on a planet where without such CIA the planet would be too cold. Using a single-column radiative-convective climate model, we investigated the effect of the presence of hydrogen on planetary temperatures and albedos across different amounts of hydrogen and across host stars of different temperatures using present-day Mars-like planets. We found that the addition of hydrogen in a planet's atmosphere increased the surface temperature of the planet. This effect was stronger for the planets orbiting hotter stars. The water vapor profiles showed that this was the case due to the presence of more water vapor in the atmospheres of planets orbiting hotter stars across all percentages of hydrogen. The water vapor concentrations also varied more with the addition of more hydrogen for the planets orbiting hotter stars.

  9. The Evolution of Stellar Rotation and the Hydrogen Atmospheres of Habitable-zone Terrestrial Planets

    NASA Astrophysics Data System (ADS)

    Johnstone, C. P.; Güdel, M.; Stökl, A.; Lammer, H.; Tu, L.; Kislyakova, K. G.; Lüftinger, T.; Odert, P.; Erkaev, N. V.; Dorfi, E. A.

    2015-12-01

    Terrestrial planets formed within gaseous protoplanetary disks can accumulate significant hydrogen envelopes. The evolution of such an atmosphere due to XUV driven evaporation depends on the activity evolution of the host star, which itself depends sensitively on its rotational evolution, and therefore on its initial rotation rate. In this Letter, we derive an easily applicable method for calculating planetary atmosphere evaporation that combines models for a hydrostatic lower atmosphere and a hydrodynamic upper atmosphere. We show that the initial rotation rate of the central star is of critical importance for the evolution of planetary atmospheres and can determine if a planet keeps or loses its primordial hydrogen envelope. Our results highlight the need for a detailed treatment of stellar activity evolution when studying the evolution of planetary atmospheres.

  10. The Stability of Hydrogen-Rich Atmospheres of Earth-Like Planets

    NASA Technical Reports Server (NTRS)

    Zahnle, Kevin

    2016-01-01

    Understanding hydrogen escape is essential to understanding the limits to habitability, both for liquid water where the Sun is bright, but also to assess the true potential of H2 as a greenhouse gas where the Sun is faint. Hydrogen-rich primary atmospheres of Earth-like planets can result either from gravitational capture of solar nebular gases (with helium), or from impact shock processing of a wide variety of volatile-rich planetesimals (typically accompanied by H2O, CO2, and under the right circumstances, CH4). Most studies of hydrogen escape from planets focus on determining how fast the hydrogen escapes. In general this requires solving hydro- dynamic equations that take into account the acceleration of hydrogen through a critical transonic point and an energy budget that should include radiative heating and cooling, thermal conduction, the work done in lifting the hydrogen against gravity, and the residual heat carried by the hydrogen as it leaves. But for planets from which hydrogen escape is modest or insignificant, the atmosphere can be approximated as hydrostatic, which is much simpler, and for which a relatively full-featured treatment of radiative cooling by embedded molecules, atoms, and ions such as CO2 and H3+ is straightforward. Previous work has overlooked the fact that the H2 molecule is extremely efficient at exciting non-LTE CO2 15 micron emission, and thus that radiative cooling can be markedly more efficient when H2 is abundant. We map out the region of phase space in which terrestrial planets keep hydrogen-rich atmospheres, which is what we actually want to know for habitability. We will use this framework to reassess Tian et al's hypothesis that H2-rich atmospheres may have been rather long-lived on Earth itself. Finally, we will address the empirical observation that rocky planets with thin or negligible atmospheres are rarely or never bigger than 1.6 Earth radii.

  11. Laser driven hydrogen transfer reactions in atmospheric chemistry

    NASA Astrophysics Data System (ADS)

    Lester, Marsha I.

    2015-03-01

    Ozonolysis of alkenes, an important non-photolytic source of OH radicals in the troposphere, proceeds through energized Criegee intermediates that undergo unimolecular decay to produce OH radicals. In this work, infrared laser activation of cold methyl-substituted Criegee intermediates is utilized to drive hydrogen transfer from the methyl group to the terminal oxygen, followed by dissociation to OH radicals. State-selective excitation of the Criegee intermediates in the CH stretch overtone region combined with sensitive OH detection reveals the infrared spectra of CH3CHOO and (CH3)2 COO, effective barrier heights for the critical hydrogen transfer step, and rapid decay dynamics to OH products. Complementary theory provides insights on the infrared overtone spectra as well as vibrational excitations, structural changes, and energy required to move from the minimum energy configuration of the Criegee intermediates to the transition state for the hydrogen transfer reaction. Research supported by the National Science Foundation.

  12. Mean molecular weight and hydrogen abundance of Titan's atmosphere

    NASA Technical Reports Server (NTRS)

    Samuelson, R. E.; Hanel, R. A.; Kunde, V. G.; Maguire, W. C.

    1981-01-01

    The 200-600/cm continuum opacity in the troposphere and lower stratosphere of Titan is inferred from thermal emission spectra from the Voyager 1 IR spectrometer (IRIS). The surface temperature and mean molecular weight are between 94 and 97 K and between 28.3 and 29.2 AMU, respectively. The mole fraction of molecular hydrogen is 0.002 + or - 0.001, which is equivalent to an abundance of approximately 0.2 + or - 0.1 km amagat.

  13. Outer satellite atmospheres: Their extended nature and planetary interactions. [sodium cloud of Io, hydrogen torus of Titan, and comet atmospheres

    NASA Technical Reports Server (NTRS)

    Smyth, W. H.

    1980-01-01

    Highly developed numerical models are applied to interpret extended-atmosphere data for the sodium cloud of Io and the hydrogen torus of Titan. Solar radiation pressure was identified and verified by model calculations as the mechanism to explain two different east-west asymmetries observed in the sodium cloud. Analysis of sodium line profile data, suggesting that a Jupiter magnetospheric wind may be responsible for high speed sodium atoms emitted from Io, and preliminary modeling of the interaction of the Io plasma torus and Io's sodium cloud are also reported. Models presented for Titan's hydrogen torus are consistent both with the recent Pioneer 11 measurements and earlier Earth-orbiting observations by the Copernicus satellite. Progress is reported on developing models for extended gas and dust atmospheres of comets.

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

    PubMed

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

    2013-06-21

    A high-temperature procedure to hydrogenate diamond films using molecular hydrogen at atmospheric pressure was explored. Undoped and doped chemical vapour deposited (CVD) polycrystalline diamond films were treated according to our annealing method using a H2 gas flow down to ~50 ml∕min (STP) at ~850 °C. The films were extensively evaluated by surface wettability, electron affinity, elemental composition, photoconductivity, and redox studies. In addition, electrografting experiments were performed. The surface characteristics as well as the optoelectronic and redox properties of the annealed films were found to be very similar to hydrogen plasma-treated films. Moreover, the presented method is compatible with atmospheric pressure and provides a low-cost solution to hydrogenate CVD diamond, which makes it interesting for industrial applications. The plausible mechanism for the hydrogen termination of CVD diamond films is based on the formation of surface carbon dangling bonds and carbon-carbon unsaturated bonds at the applied tempera-ture, which react with molecular hydrogen to produce a hydrogen-terminated surface.

  15. Hydrogen-nitrogen greenhouse warming in Earth's early atmosphere.

    PubMed

    Wordsworth, Robin; Pierrehumbert, Raymond

    2013-01-04

    Understanding how Earth has sustained surface liquid water throughout its history remains a key challenge, given that the Sun's luminosity was much lower in the past. Here we show that with an atmospheric composition consistent with the most recent constraints, the early Earth would have been significantly warmed by H(2)-N(2) collision-induced absorption. With two to three times the present-day atmospheric mass of N(2) and a H(2) mixing ratio of 0.1, H(2)-N(2) warming would be sufficient to raise global mean surface temperatures above 0°C under 75% of present-day solar flux, with CO(2) levels only 2 to 25 times the present-day values. Depending on their time of emergence and diversification, early methanogens may have caused global cooling via the conversion of H(2) and CO(2) to CH(4), with potentially observable consequences in the geological record.

  16. Detection of hydrogen peroxide (H2O2) in the Martian atmosphere with MEX / PFS

    NASA Astrophysics Data System (ADS)

    Aoki, S.; Kasaba, Y.; Giuranna, M.; Geminale, A.; Sindoni, G.; Nakagawa, H.; Kasai, Y.; Murata, I.; Grassi, D.; Formisano, V.

    2011-10-01

    We first derived the long-term averaged abundance of hydrogen peroxide (H2O2) in the Martian atmosphere with data sets of Planetary Fourier Spectroscopy (PFS) onboard Mars Express (MEX). The total averaged amounts of H2O2 at three Martian years were 45 ± 21 ppb and 25 ± 18 ppb in the forward/reverse pendulum direction, respectively. It could not explain the observed short lifetime of CH4 in the Martian atmosphere.

  17. Elevated atmospheric escape of atomic hydrogen from Mars induced by high-altitude water

    NASA Astrophysics Data System (ADS)

    Chaffin, M. S.; Deighan, J.; Schneider, N. M.; Stewart, A. I. F.

    2017-01-01

    Atmospheric loss has controlled the history of Martian habitability, removing most of the planet’s initial water through atomic hydrogen and oxygen escape from the upper atmosphere to space. In standard models, H and O escape in a stoichiometric 2:1 ratio because H reaches the upper atmosphere via long-lived molecular hydrogen, whose abundance is regulated by a photochemical feedback sensitive to atmospheric oxygen content. The relatively constant escape rates these models predict are inconsistent with known H escape variations of more than an order of magnitude on seasonal timescales, variation that requires escaping H to have a source other than H2. The best candidate source is high-altitude water, detected by the Mars Express spacecraft in seasonally variable concentrations. Here we use a one-dimensional time-dependent photochemical model to show that the introduction of high-altitude water can produce a large increase in the H escape rate on a timescale of weeks, quantitatively linking these observations. This H escape pathway produces prompt H loss that is not immediately balanced by O escape, influencing the oxidation state of the atmosphere for millions of years. Martian atmospheric water loss may be dominated by escape via this pathway, which may therefore potentially control the planet’s atmospheric chemistry. Our findings highlight the influence that seasonal atmospheric variability can have on planetary evolution.

  18. Ground-based infrared spectroscopic measurements of atmospheric hydrogen cyanide

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Smith, M. A. H.; Rinsland, P. L.; Goldman, A.; Brault, J. W.; Stokes, G. M.

    1982-01-01

    A number of lines of the nu-3 band of hydrogen cyanide have been detected in solar absorption spectra recorded near sunrise and sunset at Kitt Peak National Observatory (elevation 2095 m) with a 0.01/cm resolution Fourier transform spectrometer. Analysis of two of the strongest and best isolated lines has led to a value of 2.73 x 10 to the 15th molecules/sq cm for the vertical column abundance of HCN above Kitt Peak. The accuracy of this value is estimated as + or - 25%. This result, combined with the stratospheric concentration of HCN derived by Coffey, Mankin, and Cicerone (1981), yields 166 parts per trillion by volume for the average mixing ratio of HCN between 2 and 12 km. This is the first determination of the HCN concentration in the nonurban troposphere.

  19. Hydrogen chemistry - Perspective on experiment and theory. [atmospheric chemistry

    NASA Technical Reports Server (NTRS)

    Kaufman, F.

    1975-01-01

    A review is presented of the advantages and limitations of various experimental methods for the investigation of the kinetics of hydrogen chemistry, including classic thermal and photochemical methods and the crossed molecular beam method. Special attention is given to the flash photolysis-resonance fluorescence apparatus developed by Braun et al, in which repetitive vacuum UV flashes result in the photolytic generation of the desired species, and to the discharge-flow technique. The use of various theoretical methods for the selection or elimination of kinetic data is considered in a brief discussion of the rate theory of two-body encounters and recombination-dissociation processes in neutral reactions. Recent kinetic studies of a series of OH reactions and of a major loss process for odd H in the stratosphere are summarized.

  20. Hydrogen atom initiated chemistry. [chemical evolution in planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Hong, J. H.; Becker, R. S.

    1979-01-01

    H Atoms have been created by the photolysis of H2S. These then initiated reactions in mixtures involving acetylene-ammonia-water and ethylene-ammonia-water. In the case of the acetylene system, the products consisted of two amino acids, ethylene and a group of primarily cyclic thio-compounds, but no free sulfur. In the case of the ethylene systems, seven amino acids, including an aromatic one, ethane, free sulfur, and a group of solely linear thio-compounds were produced. Total quantum yields for the production of amino acids were about 3 x 10 to the -5th and about 2 x 10 to the -4th with ethylene and acetylene respectively as carbon substrates. Consideration is given of the mechanism for the formation of some of the products and implications regarding planetary atmosphere chemistry, particularly that of Jupiter, are explored.

  1. The signature of hot hydrogen in the atmosphere of the extrasolar planet HD 209458b

    NASA Astrophysics Data System (ADS)

    Ballester, Gilda E.; Sing, David K.; Herbert, Floyd

    2007-02-01

    About ten per cent of the known extrasolar planets are gas giants that orbit very close to their parent stars. The atmospheres of these `hot Jupiters' are heated by the immense stellar irradiation. In the case of the planet HD 209458b, this energy deposition results in a hydrodynamic state in the upper atmosphere, allowing for sizeable expansion and escape of neutral hydrogen gas. HD 209458b was the first extrasolar planet discovered that transits in front of its parent star. The size of the planet can be measured using the total optical obscuration of the stellar disk during an observed transit, and the structure and composition of the planetary atmosphere can be studied using additional planetary absorption signatures in the stellar spectrum. Here we report the detection of absorption by hot hydrogen in the atmosphere of HD 209458b. Previously, the lower atmosphere and the full extended upper atmosphere of HD 209458b have been observed, whereas here we probe a layer where the escaping gas forms in the upper atmosphere of HD 209458b.

  2. The signature of hot hydrogen in the atmosphere of the extrasolar planet HD 209458b.

    PubMed

    Ballester, Gilda E; Sing, David K; Herbert, Floyd

    2007-02-01

    About ten per cent of the known extrasolar planets are gas giants that orbit very close to their parent stars. The atmospheres of these 'hot Jupiters' are heated by the immense stellar irradiation. In the case of the planet HD 209458b, this energy deposition results in a hydrodynamic state in the upper atmosphere, allowing for sizeable expansion and escape of neutral hydrogen gas. HD 209458b was the first extrasolar planet discovered that transits in front of its parent star. The size of the planet can be measured using the total optical obscuration of the stellar disk during an observed transit, and the structure and composition of the planetary atmosphere can be studied using additional planetary absorption signatures in the stellar spectrum. Here we report the detection of absorption by hot hydrogen in the atmosphere of HD 209458b. Previously, the lower atmosphere and the full extended upper atmosphere of HD 209458b have been observed, whereas here we probe a layer where the escaping gas forms in the upper atmosphere of HD 209458b.

  3. Middle atmosphere heating by exothermic chemical reactions involving odd-hydrogen species

    NASA Technical Reports Server (NTRS)

    Mlynczak, Martin G.; Solomon, Susan

    1991-01-01

    The rate of heating which occurs in the middle atmosphere due to four exothermic reactions involving members of the odd-hydrogen family is calculated. The following reactions are considered: O + OH yields O2 + H; H + O2 + M yields HO2 + M; H + O3 yields OH + O2; and O + HO2 yields OH + O2. It is shown that the heating rates due to these reactions rival the oxygen-related heating rates conventionally considered in middle-atmosphere models. The conversion of chemical potential energy into molecular translational energy (heat) by these odd-hydrogen reactions is shown to be a significant energy source in the middle atmosphere that has not been previously considered.

  4. Carbon Dioxide in Exoplanetary Atmospheres: Rarely Dominant Compared to Carbon Monoxide and Water in Hot, Hydrogen-dominated Atmospheres

    NASA Astrophysics Data System (ADS)

    Heng, Kevin; Lyons, James R.

    2016-02-01

    We present a comprehensive study of the abundance of carbon dioxide in exoplanetary atmospheres in hot, hydrogen-dominated atmospheres. We construct novel analytical models of systems in chemical equilibrium that include carbon monoxide, carbon dioxide, water, methane and acetylene and relate the equilibrium constants of the chemical reactions to temperature and pressure via the tabulated Gibbs free energies. We prove that such chemical systems may be described by a quintic equation for the mixing ratio of methane. By examining the abundances of these molecules across a broad range of temperatures (spanning equilibrium temperatures from 600 to 2500 K), pressures (via temperature-pressure profiles that explore albedo and opacity variations) and carbon-to-oxygen ratios, we conclude that carbon dioxide is subdominant compared to carbon monoxide and water. Atmospheric mixing does not alter this conclusion if carbon dioxide is subdominant everywhere in the atmosphere. Carbon dioxide and carbon monoxide may attain comparable abundances if the metallicity is greatly enhanced, but this property is negated by temperatures above 1000 K. For hydrogen-dominated atmospheres, our generic result has the implication that retrieval studies may wish to set the subdominance of carbon dioxide as a prior of the calculation and not let its abundance completely roam free as a fitting parameter, because it directly affects the inferred value of the carbon-to-oxygen ratio and may produce unphysical conclusions. We discuss the relevance of these implications for the hot Jupiter WASP-12b and suggest that some of the previous results are chemically impossible. The relative abundance of carbon dioxide to acetylene is potentially a sensitive diagnostic of the carbon-to-oxygen ratio.

  5. On the thermal process of atomic hydrogen escape from the earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Pudovkin, M. I.; Golovchanskaia, I. V.

    1983-10-01

    The authors' approach to the problem of the escape of gases from the planetary gravitational field is close to the consideration by Biutner (1958, 1959) which generalizes results obtained by Jones (1923) for the particular cases of the dense and rarefied atmosphere. The choice of the escape layer, the height distribution of the escape probability as well as escape intensity, have been investigated carefully by Biutner when considering the helium isotope escape from the atmosphere. The objects of the present paper include: (1) to take into account the escape of atomic hydrogen from the bulk atmospheric layer (h approximately 100-1000 km) using present-day data on the composition and temperature distribution in the upper atmosphere (Jacchia, 1977), (2) to find the perturbation of the velocity distribution function in energy space under escape conditions when it is not assumed to be Maxwellian or close to it in the whole dissipation layer and (3) to compare the escape rates obtained under such consideration with the production rates of atomic hydrogen in the atmosphere as well as with local values of the fluxes that are observed. The difference between the results obtained and those of Monte Carlo calculations is attributed to the placing of the lower boundary surface at a lower atmospheric level in the present model.

  6. Signatures of hot hydrogen in the atmosphere of the extrasolar planet HD209458b

    NASA Astrophysics Data System (ADS)

    Sing, David; Ballester, G.

    2007-05-01

    Of the extrasolar planets detected so far, about 10% consist of giant planets which orbit very close to their parent stars. The atmospheres of these ``hot-Jupiters'' are largely heated by the immense stellar irradiation. In the case of the planet HD209458b, this energy deposition results in a hydrodynamic state in the upper atmosphere, allowing for sizable expansion and escape of neutral hydrogen gas. Here we report the first detection of absorption by hot (n=2) hydrogen in the optical and near-ultraviolet Balmer jump and continuum in any planet. The hot H I signature appears as a short-wavelength absorption 0.030+\\-0.006 below the value of 0.9855 calculated from the latest values for the radius of the planet. So far, the lower atmosphere and the full extended upper atmosphere of HD209458b have been observed. This work probes a layer where the escaping gas forms in HD209458b's upper atmosphere, providing a new way to study the atmospheric structure and complex escape processes of extrasolar hot-Jupiters.

  7. Atmospheric CO and hydrogen uptake and CO oxidizer phylogeny for miyake-jima, Japan volcanic deposits.

    PubMed

    King, Gary M; Weber, Carolyn F; Nanba, Kenji; Sato, Yoshinori; Ohta, Hiroyuki

    2008-01-01

    We have assayed rates of atmospheric CO and hydrogen uptake, maximum potential CO uptake and the major phylogenetic composition of CO-oxidizing bacterial communities for a variety of volcanic deposits on Miyake-jima, Japan. These deposits represented different ages and stages of plant succession, ranging from unvegetated scoria deposited in 1983 to forest soils on deposits >800 yr old. Atmospheric CO and hydrogen uptake rates varied from -2.0±1.8-6.3±0.1 mg CO m(-2) d(-1) and 0.0±0.4-2.0±0.2 mg H(2) m(-2) d(-1), respectively, and were similar to or greater than values reported for sites on Kilauea volcano, Hawaii, USA. At one of the forested sites, CO was emitted to the atmosphere, while two vegetated sites did not consume atmospheric hydrogen, an unusual observation. Although maximum potential CO uptake rates were also comparable to values for Kilauea, the relationship between these rates and organic carbon contents of scoria or soil indicated that CO oxidizers were relatively more abundant in Miyake-jima deposits. Phylogenetic analyses based on the large sub-unit gene for carbon monoxide dehydrogenase (coxL) indicated that many novel lineages were present on Miyake-jima, that CO-oxidizing Proteobacteria were prevalent in vegetated sites and that community structure appeared to vary more than composition among sites.

  8. Ortho- and para-hydrogen in dense clouds, protoplanets, and planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Decampli, W. M.; Cameron, A. G. W.; Bodenheimer, P.; Black, D. C.

    1978-01-01

    If ortho- and para-hydrogen achieve a thermal ratio on dynamical time scales in a molecular hydrogen cloud, then the specific heat is high enough in the temperature range 35-70 K to possibly induce hydrodynamic collapse. The ortho-para ratio in many interstellar cloud fragments is expected to meet this condition. The same may have been true for the primitive solar nebula. Detailed hydrodynamic and hydrostatic calculations are presented that show the effects of the assumed ortho-para ratio on the evolution of Jupiter during its protoplanetary phase. Some possible consequences of a thermalized ortho-para ratio in the atmospheres of the giant planets are also discussed.

  9. White Dwarf Period Tables I. Pulsators with hydrogen-dominated atmospheres

    NASA Astrophysics Data System (ADS)

    Bognar, Zs.; Sodor, A.

    2016-09-01

    We aimed at collecting all known white dwarf pulsators with hydrogen-dominated atmospheres and list their main photometric and atmospheric parameters together with their pulsation periods and amplitudes observed at different epochs. For this purpose, we explored the pulsating white dwarf related literature with the systematic use of the SIMBAD and the NASA's Astrophysics Data System (ADS) databases. We summarized our results in four tables listing seven ZZ Ceti stars in detached white dwarf plus main-sequence binaries, seven extremely low-mass DA pulsators, three hot DAVs and 180 ZZ Ceti stars.

  10. Energy density dependence of hydrogen combustion efficiency in atmospheric pressure microwave plasma

    SciTech Connect

    Yoshida, T.; Ezumi, N.; Sawada, K.; Tanaka, Y.; Tanaka, M.; Nishimura, K.

    2015-03-15

    The recovery of tritium in nuclear fusion plants is a key issue for safety. So far, the oxidation procedure using an atmospheric pressure plasma is expected to be part of the recovery method. In this study, in order to clarify the mechanism of hydrogen oxidation by plasma chemistry, we have investigated the dependence of hydrogen combustion efficiency on gas flow rate and input power in the atmospheric pressure microwave plasma. It has been found that the combustion efficiency depends on energy density of absorbed microwave power. Hence, the energy density is considered as a key parameter for combustion processes. Also neutral gas temperatures inside and outside the plasma were measured by an optical emission spectroscopy method and thermocouple. The result shows that the neutral gas temperature in the plasma is much higher than the outside temperature of plasma. The high neutral gas temperature may affect the combustion reaction. (authors)

  11. Dynamic transition of supercritical hydrogen: defining the boundary between interior and atmosphere in gas giants.

    PubMed

    Trachenko, K; Brazhkin, V V; Bolmatov, D

    2014-03-01

    Understanding the physics of gas giants requires knowledge about the behavior of hydrogen at extreme pressures and temperatures. Molecular hydrogen in these planets is supercritical, and has been considered as a physically homogeneous state where no differences can be made between a liquid and a gas and where all properties undergo no marked or distinct changes with pressure and temperature, the picture believed to hold below the dissociation and metallization transition. Here, we show that in Jupiter and Saturn, supercritical molecular hydrogen undergoes a dynamic transition around 10 GPa and 3000 K from the "rigid" liquid state to the "nonrigid" gas-like fluid state at the Frenkel line recently proposed, with the accompanying qualitative changes of all major physical properties. The consequences of this finding are discussed, including a physically justified way to demarcate the interior and the atmosphere in gas giants.

  12. Blowoff and escape of H2. [instability of Titan hydrogen atmospheric model

    NASA Technical Reports Server (NTRS)

    Hunten, D. M.

    1974-01-01

    It is shown that a pure hydrogen atmosphere cannot be retained by Titan, but will blow off in a few hours. Addition of a heavier gas, such as CH4 or N2, in comparable abundance gives a great improvement, although the escape rate can still be large. Moreover, the actual flux can be predicted with confidence from the mixing ratio of H2 to heavy gas.

  13. Fractionation of terrestrial neon by hydrodynamic hydrogen escape from ancient steam atmospheres

    NASA Technical Reports Server (NTRS)

    Zahnle, K.

    1991-01-01

    Atmospheric neon is isotopically heavier than mantle neon. By contrast, nonradiogenic mantle Ar, Kr, and Xe are not known to differ from the atmosphere. These observations are most easily explained by selective neon loss to space; however, neon is much too massive to escape from the modern atmosphere. Steam atmospheres are a likely, if intermittent, feature of the accreting Earth. They occur because, on average, the energy liberated during accretion places Earth above the runaway greenhouse threshold, so that liquid water is not stable at the surface. It is found that steam atmospheres should have lasted some ten to fifty million years. Hydrogen escape would have been vigorous, but abundant heavy constituents would have been retained. There is no lack of plausible candidates; CO2, N2, or CO could all suffice. Neon can escape because it is less massive than any of the likely pollutants. Neon fractionation would have been a natural byproduct. Assuming that the initial Ne-20/Ne-22 ratio was solar, it was found that it would have taken some ten million years to effect the observed neon fractionation in a 30 bar steam atmosphere fouled with 10 bars of CO. Thicker atmospheres would have taken longer; less CO, shorter. This mechanism for fractionating neon has about the right level of efficiency. Because the lighter isotope escapes much more readily, total neon loss is pretty minimal; less than half of the initial neon endowment escapes.

  14. Kinetics of suprathermal hydrogen atom reactions with saturated hydrides in planetary and satellite atmospheres

    NASA Astrophysics Data System (ADS)

    Morton, Richard J.; Kaiser, Ralf I.

    2003-05-01

    The kinetics of saturated hydrides methane (CH 4), silane (SiH 4), germane (GeH 4), ammonia (NH 3), phosphine (PH 3), arsane (AsH 3), water (H 2O), and hydrogen sulfide (H 2S) in the low-temperature atmospheres of Jupiter, Saturn, Uranus, Neptune, Pluto, Titan, and Triton reacting with suprathermal hydrogen atoms were investigated computationally to extract suprathermal rate constants k( E) via an inverse Laplace transformation from experimentally available thermal rate constants k( T). Our data reveal that all suprathermal rate constants range up to 10 -10 cm3 s-1, whereas the thermal counterparts are as low as 8×10 -73 cm3 s-1. These data demonstrate explicitly a significantly enhanced reactivity of photolytically generated suprathermal hydrogen atoms in the low-temperature planetary and satellite atmospheres and suggest that this hitherto unaccounted reaction class should be included by the planetary modeling community into future photochemical networks of atmospheres of outer solar system planets and their moons.

  15. Improvement of saturation magnetization of Fe nanoparticles by post-annealing in a hydrogen gas atmosphere

    SciTech Connect

    Kin, Masane Tanaka, Masaaki; Hayashi, Yasushi; Hasaegawa, Jun; Kura, Hiroaki; Ogawa, Tomoyuki

    2015-05-07

    Fe nanoparticles (NPs) were synthesized by the thermal decomposition of Fe(CO){sub 5} and then post-annealing in a hydrogen gas atmosphere to produce highly monodisperse Fe NPs with high saturation magnetization (M{sub s}). The as-synthesized pre-anneal Fe NPs had an expanded α-Fe structure and M{sub s} was only 39% of that for bulk Fe because of the low crystallinity and the inclusion of a surfactant. Post-annealing of the Fe NPs in a hydrogen gas atmosphere at 200 °C improved the crystallinity of the Fe NPs from an amorphous-like structure to a body centered cubic (bcc) structure without any lattice expansion. This result indicates that hydrogen gas plays a significant role in improvement of the crystallinity of Fe NPs. Accompanying the improvement in crystallinity, M{sub s} for the Fe NPs increased from 86 to 190 emu/g{sub net} at 300 K, the values of which include the weight of surfactant. This enhanced M{sub s} is almost the same as that of bulk Fe (218 emu/{sub Fe}). It was concluded that the crystallinity has a significant influence on the M{sub s} of the Fe NPs because long-range ordering of the lattice can maintain strong direct exchange interactions between Fe atoms.

  16. Trace Hydrogen in Helium Atmosphere White Dwarfs as a Possible Signature of Water Accretion

    NASA Astrophysics Data System (ADS)

    Gentile-Fusillo, N. P.; Gänsicke, B. T.; Farihi, J.; Koester, D.; Schreiber, M. R.; Pala, A. F.

    2017-03-01

    A handful of white dwarfs with helium-dominated atmospheres contain exceptionally large masses of hydrogen in their convection zones, with the metal-polluted white dwarf GD 16 being one of the earliest recognised examples. We report the discovery of a similar star: the white dwarf coincidentally named GD 17. We obtained medium-resolution spectroscopy of both GD 16 and GD 17 and calculated accretion rates and abundances of photospheric H, Mg, Ca, Ti, Fe and Ni. The metal abundance ratios indicate that the two stars recently accreted debris which is Mg-poor compared to the composition of bulk Earth. However, unlike the metal pollutants, H never diffuses out of the atmosphere of white dwarfs and we propose that the exceptionally high atmospheric H content of GD 16 and GD 17 (2.2× 1024g and 2.9× 1024g respectively) could result from previous accretion of water bearing planetesimals. Comparing the detection of trace H and metal pollution among 729 helium atmosphere white dwarfs, we find that the presence of H is nearly twice as common in metal-polluted white dwarfs compared to their metal-free counterparts. This statistically highly significant correlation indicates that a significant amount of H is accreted alongside the metal pollutants in many He atmosphere white dwarfs (including GD 16 and GD 17). We argue that H is most likely accreted in the form of water which must therefore be commonly present in systems with rocky planetesimals.

  17. Atomic-scale investigation of point defects and hydrogen-solute atmospheres on the edge dislocation mobility in alpha iron

    NASA Astrophysics Data System (ADS)

    Bhatia, M. A.; Groh, S.; Solanki, K. N.

    2014-08-01

    In this study, we present atomistic mechanisms of 1/2 [111](1 1 ¯0) edge dislocation interactions with point defects (hydrogen and vacancies) and hydrogen solute atmospheres in body centered cubic (bcc) iron. In metals such as iron, increases in hydrogen concentration can increase dislocation mobility and/or cleavage-type decohesion. Here, we first investigate the dislocation mobility in the presence of various point defects, i.e., change in the frictional stress as the edge dislocation interacts with (a) vacancy, (b) substitutional hydrogen, (c) one substitutional and one interstitial hydrogen, (d) interstitial hydrogen, (e) vacancy and interstitial hydrogen, and (f) two interstitial hydrogen. Second, we examine the role of a hydrogen-solute atmosphere on the rate of local dislocation velocity. The edge dislocation simulation with a vacancy in the compression side of the dislocation and an interstitial hydrogen atom at the tension side exhibit the strongest mechanical response, suggesting a higher potential barrier and hence, the higher frictional stress (i.e., ˜83% higher than the pure iron Peierls stress). In the case of a dislocation interacting with a vacancy on the compressive side, the vacancy binds with the edge dislocation, resulting in an increase in the friction stress of about 28% when compared with the Peierls stress of an edge dislocation in pure iron. Furthermore, as the applied strain increases, the vacancy migrates through a dislocation transportation mechanism by attaining a velocity of the same order as the dislocation velocity. For the case of the edge dislocation interacting with interstitial hydrogen on the tension side, the hydrogen atom jumps through one layer perpendicular to the glide plane during the pinning-unpinning process. Finally, our simulation of dislocation interactions with hydrogen show first an increase in the local dislocation velocity followed by a pinning of the dislocation core in the atmosphere, resulting in resistance

  18. Diphosphine is an intermediate in the photolysis of phosphine to phosphorus and hydrogen. [Jupiter atmospheric chemistry

    NASA Technical Reports Server (NTRS)

    Ferris, J. P.; Benson, R.

    1980-01-01

    The photolysis of phosphine to red phosphorus (P4) and hydrogen is investigated in light of the potential significance of the reaction in the atmospheric chemistry of Jupiter. It is reported that the photolysis of PH3 at room temperature by a 206.2-nm light source gave rise to a product identified by its UV and IR spectra and gas chromatographic retention time as P2H4, the yield of which is found to increase to a maximum and then decrease to 20% of the maximum value with illumination time. A mechanism for phosphine photolysis including diphosphine formation as an intermediate step is proposed, and it is concluded that P2H4 is a likely constituent of the atmospheres of the Jovian planets.

  19. Novel Diamond Films Synthesis Strategy: Methanol and Argon Atmosphere by Microwave Plasma CVD Method Without Hydrogen

    NASA Astrophysics Data System (ADS)

    Yang, Li; Jiang, Caiyi; Guo, Shenghui; Zhang, Libo; Gao, Jiyun; Peng, Jinhui; Hu, Tu; Wang, Liang

    2016-09-01

    Diamond thin films are grown on silicon substrates by only using methanol and argon mixtures in microwave plasma chemical vapor deposition (MPCVD) reactor. It is worth mentioning that the novel strategy makes the synthesis reaction works smoothly without hydrogen atmosphere, and the substrates temperature is only 500 °C. The evidence of surface morphology and thickness under different time is obtained by characterizing the samples using scanning electron microscopy (SEM). X-ray diffractometer (XRD) spectrum reveals that the preferential orientation of (111) plane sample is obtained. The Raman spectra indicate that the dominant component of all the samples is a diamond. Moreover, the diamond phase content of the targeted films was quantitatively analyzed by X-ray photoelectron spectroscopy (XPS) method, and the surface roughness of diamond films was investigated by atomic force microscope (AFM). Meanwhile, the possible synthesis mechanism of the diamond films in methanol- and argon-mixed atmosphere was discussed.

  20. Magnetic Hydrogen Atmosphere Models and the Neutron Star RX J1856.5-3754

    SciTech Connect

    Ho, Wynn C.G.; Kaplan, David L.; Chang, Philip; van Adelsberg, Matthew; Potekhin, Alexander Y.; /Cornell U., Astron. Dept. /Ioffe Phys. Tech. Inst.

    2006-12-08

    RX J1856.5-3754 is one of the brightest nearby isolated neutron stars, and considerable observational resources have been devoted to it. However, current models are unable to satisfactorily explain the data. We show that our latest models of a thin, magnetic, partially ionized hydrogen atmosphere on top of a condensed surface can fit the entire spectrum, from X-rays to optical, of RX J1856.5-3754, within the uncertainties. In our simplest model, the best-fit parameters are an interstellar column density N{sub H} {approx} 1 x 10{sup 20} cm{sup -2} and an emitting area with R{sup {infinity}} {approx} 17 km (assuming a distance to RX J1856.5-3754 of 140 pc), temperature T{sup {infinity}} {approx} 4.3 x 10{sup 5} K, gravitational redshift z{sub g} {approx} 0.22, atmospheric hydrogen column y{sub H} {approx} 1 g cm{sup -2}, and magnetic field B {approx} (3-4) x 10{sup 12} G; the values for the temperature and magnetic field indicate an effective average over the surface. We also calculate a more realistic model, which accounts for magnetic field and temperature variations over the neutron star surface as well as general relativistic effects, to determine pulsations; we find there exist viewing geometries that produce pulsations near the currently observed limits. The origin of the thin atmospheres required to fit the data is an important question, and we briefly discuss mechanisms for producing these atmospheres. Our model thus represents the most self-consistent picture to date for explaining all the observations of RX J1856.5-3754.

  1. Surface preparation for high purity alumina ceramics enabling direct brazing in hydrogen atmospheres

    DOEpatents

    Cadden, Charles H.; Yang, Nancy Yuan Chi; Hosking, Floyd M.

    2001-01-01

    The present invention relates to a method for preparing the surface of a high purity alumina ceramic or sapphire specimen that enables direct brazing in a hydrogen atmosphere using an active braze alloy. The present invention also relates to a method for directly brazing a high purity alumina ceramic or sapphire specimen to a ceramic or metal member using this method of surface preparation, and to articles produced by this brazing method. The presence of silicon, in the form of a SiO.sub.2 -containing surface layer, can more than double the tensile bond strength in alumina ceramic joints brazed in a hydrogen atmosphere using an active Au-16Ni-0.75 Mo-1.75V filler metal. A thin silicon coating applied by PVD processing can, after air firing, produce a semi-continuous coverage of the alumina surface with a SiO.sub.2 film. Room temperature tensile strength was found to be proportional to the fraction of air fired surface covered by silicon-containing films. Similarly, the ratio of substrate fracture versus interface separation was also related to the amount of surface silicon present prior to brazing. This process can replace the need to perform a "moly-manganese" metallization step.

  2. Hydrogen in the atmosphere: Observations above a forest canopy in a polluted environment

    NASA Astrophysics Data System (ADS)

    Barnes, Diana H.; Wofsy, Steven C.; Fehlau, Brian P.; Gottlieb, Elaine W.; Elkins, James W.; Dutton, Geoffrey S.; Novelli, Paul C.

    2003-03-01

    Long-term in situ observations of atmospheric concentrations of molecular hydrogen were monitored every 24 minutes for three years (1996-1998) above Harvard Forest, Massachusetts, in concert with measurements of carbon monoxide and twelve other trace gases. A seasonal cycle with a spring maximum and autumn minimum was observed. The diurnal cycle was characterized by a morning minimum and an afternoon maximum, reflecting the combined effects of uptake by soils and boundary height fluctuations. Enhancements of H2 concentrations in pollution events, concurrent with winds from the southwest, were typically 100-200 ppb above the background seasonal cycle. The mean molar ratio of H2 and CO (ΔH2/ΔCO) in pollution plumes was 0.396 ± 0.050 ppb/ppb. The results agree with expectations from the water-gas equilibrium (CO + H2O ↔ CO2 + H2) for conditions in automobile engines and with car emission data. These observations suggest that automobiles are the major anthropogenic source of atmospheric hydrogen and that the ratio of ΔH2/ΔCO has changed little as emission controls have taken effect.

  3. Contributions of Atmospheric CO and Hydrogen Uptake to Microbial Dynamics on Recent Hawaiian Volcanic Deposits†

    PubMed Central

    King, Gary M.

    2003-01-01

    A series of sites were established on Hawaiian volcanic deposits ranging from about 18 to 300 years old. Three sites occurred in areas that supported tropical rain forests; the remaining sites were in areas that supported little or no plant growth. Sites >26 years old consumed atmospheric CO and hydrogen at rates ranging from about 0.2 to 5 mg of CO m−2 day−1 and 0.1 to 4 mg of H2 m−2 day−1, respectively. Respiration, measured as CO2 production, for a subset of the sites ranged from about 40 to >1,400 mg of CO2 m−2 day−1. CO and H2 accounted for about 13 to 25% of reducing equivalent flow for all but a forested site, where neither substrate appeared significant. Based on responses to chloroform fumigation, hydrogen utilization appeared largely due to microbial uptake. In contrast to results for CO and hydrogen, methane uptake occurred consistently only at the forest site. Increasing deposit age was generally accompanied by increasing concentrations of organic matter and microbial biomass, measured as phospholipid phosphate. Exoenzymatic activities (acid and alkaline phosphatases and α- and β-glucosidases) were positively correlated with deposit age in spite of considerable variability within sites. The diversity of substrates utilized in Biolog Ecoplate assays also increased with deposit age, possibly reflecting changes in microbial community complexity. PMID:12839783

  4. SUPERBURST MODELS FOR NEUTRON STARS WITH HYDROGEN- AND HELIUM-RICH ATMOSPHERES

    SciTech Connect

    Keek, L.; Heger, A.; In 't Zand, J. J. M.

    2012-06-20

    Superbursts are rare day-long type I X-ray bursts due to carbon flashes on accreting neutron stars in low-mass X-ray binaries. They heat the neutron star envelope such that the burning of accreted hydrogen and helium becomes stable, and the common shorter X-ray bursts are quenched. Short bursts reappear only after the envelope cools down. We study multi-zone one-dimensional models of the neutron star envelope, in which we follow carbon burning during the superburst, and we include hydrogen and helium burning in the atmosphere above. We investigate the cases of both a solar-composition and a helium-rich atmosphere. This allows us to study for the first time a wide variety of thermonuclear burning behavior as well as the transitions between the different regimes in a self-consistent manner. For solar composition, burst quenching ends much sooner than previously expected. This is because of the complex interplay between the 3{alpha}, hot CNO, and CNO breakout reactions. Stable burning of hydrogen and helium transitions via marginally stable burning (mHz quasi-periodic oscillations) to less energetic bursts with short recurrence times. We find a short-lived bursting mode where weaker and stronger bursts alternate. Eventually the bursting behavior changes back to that of the pre-superburst bursts. Because of the scarcity of observations, this transition has not been directly detected after a superburst. Using the MINBAR burst catalog we identify the shortest upper limit on the quenching time for 4U 1636-536, and derive further constraints on the timescale on which bursts return.

  5. Consumption of atmospheric hydrogen during the life cycle of soil-dwelling actinobacteria.

    PubMed

    Meredith, Laura K; Rao, Deepa; Bosak, Tanja; Klepac-Ceraj, Vanja; Tada, Kendall R; Hansel, Colleen M; Ono, Shuhei; Prinn, Ronald G

    2014-06-01

    Microbe-mediated soil uptake is the largest and most uncertain variable in the budget of atmospheric hydrogen (H2 ). The diversity and ecophysiological role of soil microorganisms that can consume low atmospheric abundances of H2 with high-affinity [NiFe]-hydrogenases is unknown. We expanded the library of atmospheric H2 -consuming strains to include four soil Harvard Forest Isolate (HFI) Streptomyces spp., Streptomyces cattleya and Rhodococcus equi by assaying for high-affinity hydrogenase (hhyL) genes and quantifying H2 uptake rates. We find that aerial structures (hyphae and spores) are important for Streptomyces H2 consumption; uptake was not observed in S. griseoflavus Tu4000 (deficient in aerial structures) and was reduced by physical disruption of Streptomyces sp. HFI8 aerial structures. H2 consumption depended on the life cycle stage in developmentally distinct actinobacteria: Streptomyces sp. HFI8 (sporulating) and R. equi (non-sporulating, non-filamentous). Strain HFI8 took up H2 only after forming aerial hyphae and sporulating, while R. equi only consumed H2 in the late exponential and stationary phase. These observations suggest that conditions favouring H2 uptake by actinobacteria are associated with energy and nutrient limitation. Thus, H2 may be an important energy source for soil microorganisms inhabiting systems in which nutrients are frequently limited.

  6. Studies of Evaluation of Hydrogen Embrittlement Property of High-Strength Steels with Consideration of the Effect of Atmospheric Corrosion

    NASA Astrophysics Data System (ADS)

    Akiyama, Eiji; Wang, Maoqiu; Li, Songjie; Zhang, Zuogui; Kimura, Yuuji; Uno, Nobuyoshi; Tsuzaki, Kaneaki

    2013-03-01

    Hydrogen embrittlement of high-strength steels was investigated by using slow strain rate test (SSRT) of circumferentially notched round bar specimens after hydrogen precharging. On top of that, cyclic corrosion tests (CCT) and outdoor exposure tests were conducted prior to SSRT to take into account the effect of hydrogen uptake under atmospheric corrosion for the evaluation of the susceptibility of high-strength steels. Our studies of hydrogen embrittle properties of high-strength steels with 1100 to 1500 MPa of tensile strength and a prototype ultrahigh-strength steel with 1760 MPa containing hydrogen traps using those methods are reviewed in this article. A power law relationship between notch tensile strength of hydrogen-precharged specimens and diffusible hydrogen content has been found. It has also been found that the local stress and the local hydrogen concentration are controlling factors of fracture. The results obtained by using SSRT after CCT and outdoor exposure test were in good agreement with the hydrogen embrittlement fracture property obtained by means of long-term exposure tests of bolts made of the high-strength steels.

  7. Atmospheric molecular hydrogen (H2) at the Shangdianzi regional background station in China

    NASA Astrophysics Data System (ADS)

    Luan, Tian; Fang, Shuangxi; Yao, Bo; Wang, Hongyang; Dong, Fan; Shi, Qingfeng; Zhou, Liyan; Zhou, Huaigang

    2016-11-01

    Atmospheric molecular hydrogen (H2) mole fractions have been continuously measured at the Shangdianzi regional station in China. In this study, we present the atmospheric H2 time series from January 2015 to April 2016, and investigate the diurnal and seasonal cycles, and the impact of meteorological factors on the observed values. Atmospheric H2 mole fractions at Shangdianzi vary from a minimum of 381 ppb (parts per billion, 10-9 dry air mole fraction) to a maximum of 1535 ppb, with a median of 510 ppb and a mean (± standard deviation) of 555 ± 113 ppb during the observation period. The results indicate that H2 mole fractions at Shangdianzi are frequently influenced by local sources and sinks. Regionally representative conditions account for 44.7% of the total records with a mean mole fraction of 488 ± 20 ppb. The highest regionally representative H2 mole fraction is observed in July, while the lowest is observed in October. Peak-to-trough amplitude in the seasonal cycle is 63 ± 3 ppb. H2 mole fractions show nighttime depletion in all seasons, with the lowest values in the morning (7:00-10:00 local time). The H2 mole fractions are also influenced by local surface wind direction at Shangdianzi. Winds from NW-NNW-N-NNE-NE-ENE-E directions are always associated with negative contribution to atmospheric H2 loading, whereas winds from SSW-SW-WSW-W directions generally enhance the H2 values. The results of trajectory clustering analysis demonstrate that air masses from a southerly direction induce high H2 mole fractions. Conversely, mean H2 mole fractions are low when air masses are from the north, northwest, and east directions.

  8. A probabilistic approach to radiative energy loss calculations for optically thick atmospheres - Hydrogen lines and continua

    NASA Technical Reports Server (NTRS)

    Canfield, R. C.; Ricchiazzi, P. J.

    1980-01-01

    An approximate probabilistic radiative transfer equation and the statistical equilibrium equations are simultaneously solved for a model hydrogen atom consisting of three bound levels and ionization continuum. The transfer equation for L-alpha, L-beta, H-alpha, and the Lyman continuum is explicitly solved assuming complete redistribution. The accuracy of this approach is tested by comparing source functions and radiative loss rates to values obtained with a method that solves the exact transfer equation. Two recent model solar-flare chromospheres are used for this test. It is shown that for the test atmospheres the probabilistic method gives values of the radiative loss rate that are characteristically good to a factor of 2. The advantage of this probabilistic approach is that it retains a description of the dominant physical processes of radiative transfer in the complete redistribution case, yet it achieves a major reduction in computational requirements.

  9. Thermodynamic analysis of chemical stability of ceramic materials in hydrogen-containing atmospheres at high temperatures

    NASA Technical Reports Server (NTRS)

    Misra, Ajay K.

    1990-01-01

    The chemical stability of several ceramic materials in hydrogen-containing environments was analyzed with thermodynamic considerations in mind. Equilibrium calculations were made as a function of temperature, moisture content, and total system pressure. The following ceramic materials were considered in this study: SiC, Si3N4, SiO2, Al2O3, mullite, ZrO2, Y2O3, CaO, MgO, BeO, TiB2, TiC, HfC, and ZrC. On the basis of purely thermodynamic arguments, upper temperature limits are suggested for each material for long-term use in H2-containing atmospheres.

  10. Hydrogen Isotopic Composition of Water in the Martian Atmosphere and Released from Rocknest Fines

    NASA Technical Reports Server (NTRS)

    Leshin, L. A.; Webster, C. R.; Mahaffy, P. R.; Flesh, G. J.; Christensen, L. E.; Stern, J. C.; Franz, H. B.; McAdam, A. C.; Niles, P. B.; Archer, P. B., Jr.; Sutter, B.; Jones, J. H.; Ming, D. W.; Atreya, S. K.; Owen, T. C.; Conrad, P.

    2013-01-01

    The Mars Science Laboratory Curiosity rover sampled the aeolian bedform called Rocknest as its first solid samples to be analyzed by the analytical instruments CheMin and SAM. The instruments ingested aliquots from a sieved sample of less than 150 micrometer grains. As discussed in other reports at this conference [e.g., 1], CheMin discovered many crystalline phases, almost all of which are igneous minerals, plus some 10s of percent of x-ray amorphous material. The SAM instrument is focused on understanding volatiles and possible organics in the fines, performing evolved gas analysis (EGA) with the SAM quadrapole mass spectrometer (QMS), isotope measurements using both the QMS and the tunable laser spectrometer (TLS), which is sensitive to CO2, water and methane, and organics with the gas chromatograph mass spectrometer (GCMS). As discussed in the abstract by Franz et al. [2] and others, EGA of Rocknest fines revealed the presence of significant amounts of H2O as well as O-, C- and S-bearing materials. SAM has also tasted the martian atmosphere several times, analyzing the volatiles in both the TLS and QMS [e.g., 3,4]. This abstract will focus on presentation of initial hydrogen isotopic data from the TLS for Rocknest soils and the atmosphere, and their interpretation. Data for CO2 isotopes and O isotopes in water are still being reduced, but should be available by at the conference.

  11. Thermodynamics of a solar mixture of molecular hydrogen and helium at high pressure. [for Jupiter atmospheric model

    NASA Technical Reports Server (NTRS)

    Slattery, W. L.; Hubbard, W. B.

    1976-01-01

    The thermodynamic properties of a model molecular hydrogen and helium mixture are calculated in the strongly interacting region of 0.005 to 0.3 per cu cm for a range of temperatures that are of interest for the envelopes of the Jovian planets. Computed adiabats fit the gravity data and boundary conditions from model atmospheres of Jupiter.

  12. XUV-Exposed, Non-Hydrostatic Hydrogen-Rich Upper Atmospheres of Terrestrial Planets. Part II: Hydrogen Coronae and Ion Escape

    PubMed Central

    Lammer, Helmut; Holmström, Mats; Panchenko, Mykhaylo; Odert, Petra; Erkaev, Nikolai V.; Leitzinger, Martin; Khodachenko, Maxim L.; Kulikov, Yuri N.; Güdel, Manuel; Hanslmeier, Arnold

    2013-01-01

    Abstract We studied the interactions between the stellar wind plasma flow of a typical M star, such as GJ 436, and the hydrogen-rich upper atmosphere of an Earth-like planet and a “super-Earth” with a radius of 2 REarth and a mass of 10 MEarth, located within the habitable zone at ∼0.24 AU. We investigated the formation of extended atomic hydrogen coronae under the influences of the stellar XUV flux (soft X-rays and EUV), stellar wind density and velocity, shape of a planetary obstacle (e.g., magnetosphere, ionopause), and the loss of planetary pickup ions on the evolution of hydrogen-dominated upper atmospheres. Stellar XUV fluxes that are 1, 10, 50, and 100 times higher compared to that of the present-day Sun were considered, and the formation of high-energy neutral hydrogen clouds around the planets due to the charge-exchange reaction under various stellar conditions was modeled. Charge-exchange between stellar wind protons with planetary hydrogen atoms, and photoionization, lead to the production of initially cold ions of planetary origin. We found that the ion production rates for the studied planets can vary over a wide range, from ∼1.0×1025 s−1 to ∼5.3×1030 s−1, depending on the stellar wind conditions and the assumed XUV exposure of the upper atmosphere. Our findings indicate that most likely the majority of these planetary ions are picked up by the stellar wind and lost from the planet. Finally, we estimated the long-time nonthermal ion pickup escape for the studied planets and compared them with the thermal escape. According to our estimates, nonthermal escape of picked-up ionized hydrogen atoms over a planet's lifetime within the habitable zone of an M dwarf varies between ∼0.4 Earth ocean equivalent amounts of hydrogen (EOH) to <3 EOH and usually is several times smaller in comparison to the thermal atmospheric escape rates. Key Words: Stellar activity—Low-mass stars—Early atmospheres—Earth-like exoplanets—Energetic neutral

  13. XUV-exposed, non-hydrostatic hydrogen-rich upper atmospheres of terrestrial planets. Part II: hydrogen coronae and ion escape.

    PubMed

    Kislyakova, Kristina G; Lammer, Helmut; Holmström, Mats; Panchenko, Mykhaylo; Odert, Petra; Erkaev, Nikolai V; Leitzinger, Martin; Khodachenko, Maxim L; Kulikov, Yuri N; Güdel, Manuel; Hanslmeier, Arnold

    2013-11-01

    We studied the interactions between the stellar wind plasma flow of a typical M star, such as GJ 436, and the hydrogen-rich upper atmosphere of an Earth-like planet and a "super-Earth" with a radius of 2 R(Earth) and a mass of 10 M(Earth), located within the habitable zone at ∼0.24 AU. We investigated the formation of extended atomic hydrogen coronae under the influences of the stellar XUV flux (soft X-rays and EUV), stellar wind density and velocity, shape of a planetary obstacle (e.g., magnetosphere, ionopause), and the loss of planetary pickup ions on the evolution of hydrogen-dominated upper atmospheres. Stellar XUV fluxes that are 1, 10, 50, and 100 times higher compared to that of the present-day Sun were considered, and the formation of high-energy neutral hydrogen clouds around the planets due to the charge-exchange reaction under various stellar conditions was modeled. Charge-exchange between stellar wind protons with planetary hydrogen atoms, and photoionization, lead to the production of initially cold ions of planetary origin. We found that the ion production rates for the studied planets can vary over a wide range, from ∼1.0×10²⁵ s⁻¹ to ∼5.3×10³⁰ s⁻¹, depending on the stellar wind conditions and the assumed XUV exposure of the upper atmosphere. Our findings indicate that most likely the majority of these planetary ions are picked up by the stellar wind and lost from the planet. Finally, we estimated the long-time nonthermal ion pickup escape for the studied planets and compared them with the thermal escape. According to our estimates, nonthermal escape of picked-up ionized hydrogen atoms over a planet's lifetime within the habitable zone of an M dwarf varies between ∼0.4 Earth ocean equivalent amounts of hydrogen (EO(H)) to <3 EO(H) and usually is several times smaller in comparison to the thermal atmospheric escape rates.

  14. Search for hydrogen peroxide in the Martian atmosphere by the Planetary Fourier Spectrometer onboard Mars Express

    NASA Astrophysics Data System (ADS)

    Aoki, Shohei; Giuranna, Marco; Kasaba, Yasumasa; Nakagawa, Hiromu; Sindoni, Giuseppe; Geminale, Anna; Formisano, Vittorio

    2015-01-01

    We searched for hydrogen peroxide (H2O2) in the Martian atmosphere using data measured by the Planetary Fourier Spectrometer (PFS) onboard Mars Express during five martian years (MY27-31). It is well known that H2O2 plays a key role in the oxidizing capacity of the Martian atmosphere. However, only a few studies based on ground-based observations can be found in the literature. Here, we performed the first analysis of H2O2 using long-term measurements by a spacecraft-borne instrument. We used the ν4 band of H2O2 in the spectral range between 359 cm-1 and 382 cm-1 where strong features of H2O2 are present around 362 cm-1 and 379 cm-1. Since the features were expected to be very weak even at the strong band, sensitive data calibrations were performed and a large number of spectra were selected and averaged. We made three averaged spectra for different seasons over relatively low latitudes (50°S-50°N). We found features of H2O2 at 379 cm-1, whereas no clear features were detected at 362 cm-1 due to large amounts of uncertainty in the data. The derived mixing ratios of H2O2 were close to the detection limits: 16 ± 19 ppb at Ls = 0-120°, 35 ± 32 ppb at Ls = 120-240°, and 41 ± 28 ppb at Ls = 240-360°. The retrieved value showed the detection of H2O2 only for the third seasonal period, and the values in the other periods provided the upper limits. These long-term averaged abundances derived by the PFS generally agreed with the ones reported by ground-based observations. From our derived mixing ratio of H2O2, the lifetime of CH4 in the Martian atmosphere is estimated to be several decades in the shortest case. Our results and sporadic detections of CH4 suggest the presence of strong CH4 sinks not subject to atmospheric oxidation.

  15. The Role of Hydrogen in Determining the Stability of CO2 Atmospheres of Terrestrial Exoplanets Around M Dwarfs

    NASA Astrophysics Data System (ADS)

    Gao, Peter; Hu, Renyu; Robinson, Tyler D.; Yung, Yuk L.

    2014-11-01

    The recent discovery of terrestrial worlds in the Habitable Zones of M Dwarfs necessitates a more intensive investigation of the properties of these planets. One major feature of certain M Dwarfs is their high fluxes of EUV radiation, which photolyzes CO2, an important greenhouse gas that should be abundant on rocky worlds. This photolytic destruction of CO2 can be countered by HOx chemistry: photolysis of HOx species by NUV radiation generates OH, which reacts with CO to regenerate CO2. These processes are balanced around Sun-like stars such that Venus and Mars can maintain CO2-dominated atmospheres. However, M Dwarfs tend to have much lower NUV/EUV flux ratios, which could prevent the formation of significant CO2 atmospheres on any planets they may host. In this study, we evaluate the properties of CO2 atmospheres surrounding an Earth-massed, Earth-sized exoplanet in orbit of an M Dwarf using a 1D photochemical kinetics model. We consider an atmosphere similar in composition to that of Mars, but scaled to have a surface pressure of 1 bar. We choose to focus on Mars-like atmospheres rather than Earth-like ones, as Earth's atmosphere has been altered through biological sources and sinks and the presence of a large liquid water ocean, which are not necessarily present on terrestrial exoplanets. Our preliminary results show that the hydrogen content of the atmosphere is crucial in determining the ratio of CO2 to CO and O2. In particular, for a H2 mixing ratio identical to that of Mars 20-30 ppm), a steady state atmosphere is reached after 10 Gyr consisting of ~85% CO2, ~10% CO, and ~5% O2, with an ozone mixing ratio of ~0.01 ppm. In the extreme case where all hydrogen is lost to space, an atmosphere consisting of ~64% CO2, ~24% CO, and 12% O2 results, while ozone levels reach ~10 ppm. Finally, for H2 mixing ratios similar to that of Earth 0.5 ppm) and no atmospheric escape, a 49% CO2, 34% CO, 17% O2, and 0.1 ppm O3 atmosphere is possible. This not only points to the

  16. The interaction of an atmospheric pressure plasma jet using argon or argon plus hydrogen peroxide vapour addition with bacillus subtilis

    NASA Astrophysics Data System (ADS)

    Deng, San-Xi; Cheng, Cheng; Ni, Guo-Hua; Meng, Yue-Dong; Chen, Hua

    2010-10-01

    This paper reports that an atmospheric pressure dielectric barrier discharge plasma jet, which uses argon or argon + hydrogen peroxide vapour as the working gas, is designed to sterilize the bacillus subtilis. Compared with the pure argon plasma, the bacterial inactivation efficacy has a significant improvement when hydrogen peroxide vapour is added into the plasma jet. In order to determine which factors play the main role in inactivation, several methods are used, such as determination of optical emission spectra, high temperature dry air treatment, protein leakage quantification, and scanning electron microscope. These results indicate that the possible inactivation mechanisms are the synergistic actions of chemically active species and charged species.

  17. Measurements of atmospheric dimethylsulfide, hydrogen sulfide, and carbon disulfide during GTE/CITE 3

    NASA Technical Reports Server (NTRS)

    Cooper, David J.; Saltzman, Eric S.

    1993-01-01

    Measurements of atmospheric dimethylsulfide (DMS), hydrogen sulfide (H2S), and carbon disulfide (CS2) were made over the North and South Atlantic Ocean as part of the Global Tropospheric Experiment/Chemical Instrumentation Test and Evaluation (GTE/CITE 3) project. DMS and CS2 samples were collected and analyzed using an automated gas chromatography/flame photometric detection system with a sampling frequency of 10 min. H2S samples were collected using silver nitrate impregnated filters and analyzed by fluorescence quenching. The DMS data from both hemispheres have a bimodal distribution. Over the North Atlantic this reflects the difference between marine and continental air masses. Over the South Atlantic it may reflect differences in the sea surface source of DMS, corresponding to different air mass source regions. The median boundary layer H2S and CS2 levels were significantly higher in the northern hemisphere than the southern hemisphere, reflecting the higher frequency of samples influenced by pollutant and/or coastal emissions. Composite vertical profiles of DMS and H2S are similar to each other, are consistent with a sea surface source. Vertical profiles of CS2 have maxima in the free troposphere, implicating a continental source. The low levels of H2S and CS2 found in the southern hemisphere constrain the role of these compounds in global budgets to significantly less than previously estimated.

  18. Measurements of atmospheric dimethylsulfide, hydrogen sulfide, and carbon disulfide during GTE/CITE 3

    NASA Astrophysics Data System (ADS)

    Cooper, David J.; Saltzman, Eric S.

    1993-12-01

    Measurements of atmospheric dimethylsulfide (DMS), hydrogen sulfide (H2S), and carbon disulfide (CS2) were made over the North and South Atlantic Ocean as part of the Global Tropospheric Experiment/Chemical Instrumentation Test and Evaluation (GTE/CITE 3) project. DMS and CS2 samples were collected and analyzed using an automated gas chromatography/flame photometric detection system with a sampling frequency of 10 min. H2S samples were collected using silver nitrate impregnated filters and analyzed by fluorescence quenching. The DMS data from both hemispheres have a bimodal distribution. Over the North Atlantic this reflects the difference between marine and continental air masses. Over the South Atlantic it may reflect differences in the sea surface source of DMS, corresponding to different air mass source regions. The median boundary layer H2S and CS2 levels were significantly higher in the northern hemisphere than the southern hemisphere, reflecting the higher frequency of samples influenced by pollutant and/or coastal emissions. Composite vertical profiles of DMS and H2S are similar to each other, and are consistent with a sea surface source. Vertical profiles of CS2 have maxima in the free troposphere, implicating a continental source. The low levels of H2S and CS2 found in the southern hemisphere constrain the role of these compounds in global budgets to significantly less than previously estimated.

  19. A new estimation of the recent tropospheric molecular hydrogen budget using atmospheric observations and variational inversion

    NASA Astrophysics Data System (ADS)

    Yver, C.; Pison, I.; Fortems-Cheiney, A.; Schmidt, M.; Bousquet, P.; Ramonet, M.; Jordan, A.; Søvde, A.; Engel, A.; Fisher, R.; Lowry, D.; Nisbet, E.; Levin, I.; Hammer, S.; Necki, J.; Bartyzel, J.; Reimann, S.; Vollmer, M. K.; Steinbacher, M.; Aalto, T.; Maione, M.; Arduini, I.; O'Doherty, S.; Grant, A.; Sturges, W.; Lunder, C. R.; Privalov, V.; Paramonova, N.

    2010-11-01

    This paper presents an analysis of the recent tropospheric molecular hydrogen (H2) budget with a particular focus on soil uptake and surface emissions. A variational inversion scheme is combined with observations from the RAMCES and EUROHYDROS atmospheric networks, which include continuous measurements performed between mid-2006 and mid-2009. Net H2 surface flux, soil uptake distinct from surface emissions and finally, soil uptake, biomass burning, anthropogenic emissions and N2 fixation-related emissions separately were inverted in several scenarios. The various inversions generate an estimate for each term of the H2 budget. The net H2 flux per region (High Northern Hemisphere, Tropics and High Southern Hemisphere) varies between -8 and 8 Tg yr-1. The best inversion in terms of fit to the observations combines updated prior surface emissions and a soil deposition velocity map that is based on soil uptake measurements. Our estimate of global H2 soil uptake is -59 ± 4.0 Tg yr-1. Forty per cent of this uptake is located in the High Northern Hemisphere and 55% is located in the Tropics. In terms of surface emissions, seasonality is mainly driven by biomass burning emissions. The inferred European anthropogenic emissions are consistent with independent H2 emissions estimated using a H2/CO mass ratio of 0.034 and CO emissions considering their respective uncertainties. To constrain a more robust partition of H2 sources and sinks would need additional constraints, such as isotopic measurements.

  20. Measurements of atmospheric hydrogen peroxide in the gas phase and in cloud water at Mt. Mitchell, North Carolina

    NASA Astrophysics Data System (ADS)

    Claiborn, Clandis S.; Aneja, Viney P.

    1991-10-01

    Measurements of atmospheric hydrogen peroxide in the gas phase were made during four intensive observation periods at the Mt. Mitchell State Park, North Carolina, during the growing season (May through September) of 1988. Cloud water hydrogen peroxide was measured during the entire field season of 1988 and during the late summer and fall of 1987 (August and October). Cloud water concentrations were found to be similar to those reported from another high-elevation location in the southeastern United States. Cloud water samples collected during these periods showed a wide range of levels (˜ 0 - 219 μM/L ) and average values of 38 μM/L and 44 μM/L for the entire sampling seasons of 1988 and 1987, respectively. Significant seasonal variation was noted both in 1987 and 1988, with cloud water levels of hydrogen peroxide much higher in the summer than in the fall. Gas-phase hydrogen peroxide levels ranged from the detection limit (0.1 ppbv) to above 4 ppbv. Gas-phase hydrogen peroxide demonstrated a nighttime maximum in the summer but not in the fall. The measurements taken in the fall were significantly lower than those taken during the summer, possibly due at least in part to seasonal variation. Atmospheric hydrogen peroxide levels were found to be increasing during stagnating high-pressure systems and were found to correspond to the back trajectory of the air mass with the highest concentrations corresponding to continental air masses. The hydrogen peroxide concentration was also found to be affected by radical formation from ozone and by loss processes such as wet and dry deposition.

  1. Hydrogen production from banyan leaves using an atmospheric-pressure microwave plasma reactor.

    PubMed

    Lin, Yuan-Chung; Wu, Tzi-Yi; Jhang, Syu-Ruei; Yang, Po-Ming; Hsiao, Yi-Hsing

    2014-06-01

    Growth of the hydrogen market has motivated increased study of hydrogen production. Understanding how biomass is converted to hydrogen gas can help in evaluating opportunities for reducing the environmental impact of petroleum-based fuels. The microwave power used in the reaction is found to be proportional to the rate of production of hydrogen gas, mass of hydrogen gas produced per gram of banyan leaves consumed, and amount of hydrogen gas formed with respect to the H-atom content of banyan leaves decomposed. Increase the microwave power levels results in an increase of H2 and decrease of CO2 concentrations in the gaseous products. This finding may possibly be ascribed to the water-gas shift reaction. These results will help to expand our knowledge concerning banyan leaves and hydrogen yield on the basis of microwave-assisted pyrolysis, which will improve the design of hydrogen production technologies.

  2. XUV-Exposed, Non-Hydrostatic Hydrogen-Rich Upper Atmospheres of Terrestrial Planets. Part I: Atmospheric Expansion and Thermal Escape

    PubMed Central

    Lammer, Helmut; Odert, Petra; Kulikov, Yuri N.; Kislyakova, Kristina G.; Khodachenko, Maxim L.; Güdel, Manuel; Hanslmeier, Arnold; Biernat, Helfried

    2013-01-01

    Abstract The recently discovered low-density “super-Earths” Kepler-11b, Kepler-11f, Kepler-11d, Kepler-11e, and planets such as GJ 1214b represent the most likely known planets that are surrounded by dense H/He envelopes or contain deep H2O oceans also surrounded by dense hydrogen envelopes. Although these super-Earths are orbiting relatively close to their host stars, they have not lost their captured nebula-based hydrogen-rich or degassed volatile-rich steam protoatmospheres. Thus, it is interesting to estimate the maximum possible amount of atmospheric hydrogen loss from a terrestrial planet orbiting within the habitable zone of late main sequence host stars. For studying the thermosphere structure and escape, we apply a 1-D hydrodynamic upper atmosphere model that solves the equations of mass, momentum, and energy conservation for a planet with the mass and size of Earth and for a super-Earth with a size of 2 REarth and a mass of 10 MEarth. We calculate volume heating rates by the stellar soft X-ray and extreme ultraviolet radiation (XUV) and expansion of the upper atmosphere, its temperature, density, and velocity structure and related thermal escape rates during the planet's lifetime. Moreover, we investigate under which conditions both planets enter the blow-off escape regime and may therefore experience loss rates that are close to the energy-limited escape. Finally, we discuss the results in the context of atmospheric evolution and implications for habitability of terrestrial planets in general. Key Words: Stellar activity—Low-mass stars—Early atmospheres—Earth-like exoplanets—Energetic neutral atoms—Ion escape—Habitability. Astrobiology 13, 1011–1029. PMID:24251443

  3. XUV-exposed, non-hydrostatic hydrogen-rich upper atmospheres of terrestrial planets. Part I: atmospheric expansion and thermal escape.

    PubMed

    Erkaev, Nikolai V; Lammer, Helmut; Odert, Petra; Kulikov, Yuri N; Kislyakova, Kristina G; Khodachenko, Maxim L; Güdel, Manuel; Hanslmeier, Arnold; Biernat, Helfried

    2013-11-01

    The recently discovered low-density "super-Earths" Kepler-11b, Kepler-11f, Kepler-11d, Kepler-11e, and planets such as GJ 1214b represent the most likely known planets that are surrounded by dense H/He envelopes or contain deep H₂O oceans also surrounded by dense hydrogen envelopes. Although these super-Earths are orbiting relatively close to their host stars, they have not lost their captured nebula-based hydrogen-rich or degassed volatile-rich steam protoatmospheres. Thus, it is interesting to estimate the maximum possible amount of atmospheric hydrogen loss from a terrestrial planet orbiting within the habitable zone of late main sequence host stars. For studying the thermosphere structure and escape, we apply a 1-D hydrodynamic upper atmosphere model that solves the equations of mass, momentum, and energy conservation for a planet with the mass and size of Earth and for a super-Earth with a size of 2 R(Earth) and a mass of 10 M(Earth). We calculate volume heating rates by the stellar soft X-ray and extreme ultraviolet radiation (XUV) and expansion of the upper atmosphere, its temperature, density, and velocity structure and related thermal escape rates during the planet's lifetime. Moreover, we investigate under which conditions both planets enter the blow-off escape regime and may therefore experience loss rates that are close to the energy-limited escape. Finally, we discuss the results in the context of atmospheric evolution and implications for habitability of terrestrial planets in general.

  4. Production of Hydrogen and Carbon Nanotube by direct decomposition of methane using pulsed corona discharge under th atmospheric pressure.

    NASA Astrophysics Data System (ADS)

    Nath Mishra, Lekha; Shibata, Kanetoshi; Ito, Hiroaki; Yugami, Noboru; Nishida, Yasushi

    2003-10-01

    In future, hydrogen is supposed to play an important role in the worldwide energy supply. It allows a more efficient utilization of fossil fuels and the reduction of noxoous emissions, e.g. by fuel cells or the use of hydrogen enriched fuels in the combustion engines or gas turbines. Plasma methods are expected to allow low temperature and fuel flexible on-site hydrogen generation. Experiments are performed to develop a pulsed corona discharge system for the production of hydrogen and carbon nanotubes by direct methane decomposition under the atmospheric pressure. The corona discharge is energized by 10-20μs wide voltage pulses (≤7kV) at a repetition rate of 0-5000 pulses per second. The spectrum of the gas is carried out by Mass Spectrometer. Experimentally, it is shown that the production of hydrogen gas depends on the pulsed width, input voltage, frequency, current and discharge time. The spectrum noted by the Mass Spectrometer is also presented. The structural geometry of the carbon nanotube is observed by Transmission Electron Microscope (TEM) and Scanig Electron Microscopy (SEM). The soot for this purpose is collected from the cathode. Different lengths noted for different soot collected from different parts with the help of TEM are also presented. The present experimental technique could be applicable for the future energy source using hydrogen and the nanoelectronics.

  5. Stable hydrogen isotope composition of n-alkanes in urban atmospheric aerosols in Taiyuan, China

    NASA Astrophysics Data System (ADS)

    Bai, Huiling; Li, Yinghui; Peng, Lin; Liu, Xiangkai; Liu, Xiaofeng; Song, Chongfang; Mu, Ling

    2017-03-01

    The hydrogen isotope compositions (δD) of n-alkanes associated with particulate matter with a diameter of ≤10 μm from Taiyuan, China, during heating and non-heating periods were measured via gas chromatography-isotope ratio mass spectrometry to reveal the spatial and temporal characteristics of five functional zones and to provide another constraint on atmospheric pollutants. The δD values of n-C16 to n-C31 during the heating and non-heating periods ranged from -235.9‰ to -119.8‰ and from -231.3‰ to -129.2‰, respectively, but these similar spans had different distribution features. During the heating period, the δD distributions between non-central heating and commercial districts were consistent, as were those between residential and industrial districts; the n-alkanes came from two or more types of emission sources. Coal soot might be the primary local emission source, but not the only source. During the non-heating period, the n-alkanes of n-C16 to n-C20 were more depleted in D with the increasing carbon number in all functional zones, but there was no rule for n-C21 to n-C31. Specifically, coal soot and vehicle exhaust might be the primary sources of n-alkanes for non-central heating districts in the heating and non-heating periods, respectively, according to the δD distribution of n-C18 to n-C22; gasoline vehicle exhaust might be an n-alkane source, and the hydrogen isotope fractionation effect during the condensation process should be a pollution mechanism for the commercial district during the heating period; the δD distribution difference of n-C16 to n-C18 between the two periods in the residential and industrial districts was consistent, which indicates a similar source of fossil fuel combustion and a similar isotope fractionation effect during the non-heating period.

  6. The effects of added hydrogen on a helium atmospheric-pressure plasma jet ambient desorption/ionization source.

    PubMed

    Wright, Jonathan P; Heywood, Matthew S; Thurston, Glen K; Farnsworth, Paul B

    2013-03-01

    We present mass spectrometric data demonstrating the effect that hydrogen has on a helium-based dielectric-barrier discharge (DBD) atmospheric-pressure plasma jet used as an ambient desorption/ionization (ADI) source. The addition of 0.9 % hydrogen to the helium support gas in a 35-W plasma jet increased signals for a range of test analytes, with enhancement factors of up to 68, without proportional increases in background levels. The changes in signal levels result from a combination of changes in the desorption kinetics from the surface and increased ion production in the gas phase. The enhancement in ADI-MS performance despite the quenching of key plasma species reported in earlier studies suggests that ionization with a H2/He plasma jet is the result of an alternate mechanism involving the direct generation of ionized hydrogen.

  7. Sputtering deposition of P-type SnO films with SnO₂ target in hydrogen-containing atmosphere.

    PubMed

    Hsu, Po-Ching; Hsu, Chao-Jui; Chang, Ching-Hsiang; Tsai, Shiao-Po; Chen, Wei-Chung; Hsieh, Hsing-Hung; Wu, Chung-Chih

    2014-08-27

    In this work, we had investigated sputtering deposition of p-type SnO using the widely used and robust SnO2 target in a hydrogen-containing reducing atmosphere. The effects of the hydrogen-containing sputtering gas on structures, compositions, optical, and electrical properties of deposited SnOx films were studied. Results show that polycrystalline and SnO-dominant films could be readily obtained by carefully controlling the hydrogen gas ratio in the sputtering gas and the extent of reduction reaction. P-type conductivity was unambiguously observed for SnO-dominant films with traceable Sn components, exhibiting a p-type Hall mobility of up to ∼3 cm(2) V(-1) s(-1). P-type SnO thin-film transistors using such SnO-dominant films were also demonstrated.

  8. Pathways to Earth-Like Atmospheres. Extreme Ultraviolet (EUV)-Powered Escape of Hydrogen-Rich Protoatmospheres

    NASA Astrophysics Data System (ADS)

    Lammer, Helmut; Kislyakova, K. G.; Odert, P.; Leitzinger, M.; Schwarz, R.; Pilat-Lohinger, E.; Kulikov, Yu. N.; Khodachenko, M. L.; Güdel, M.; Hanslmeier, A.

    2011-12-01

    We discuss the evolution of the atmosphere of early Earth and of terrestrial exoplanets which may be capable of sustaining liquid water oceans and continents where life may originate. The formation age of a terrestrial planet, its mass and size, as well as the lifetime in the EUV-saturated early phase of its host star play a significant role in its atmosphere evolution. We show that planets even in orbits within the habitable zone of their host stars might not lose nebular- or catastrophically outgassed initial protoatmospheres completely and could end up as water worlds with CO2 and hydrogen- or oxygen-rich upper atmospheres. If an atmosphere of a terrestrial planet evolves to an N2-rich atmosphere too early in its lifetime, the atmosphere may be lost. We show that the initial conditions set up by the formation of a terrestrial planet and by the evolution of the host star's EUV and plasma environment are very important factors owing to which a planet may evolve to a habitable world. Finally we present a method for studying the discussed atmosphere evolution hypotheses by future UV transit observations of terrestrial exoplanets.

  9. Pathways to Earth-like atmospheres. Extreme ultraviolet (EUV)-powered escape of hydrogen-rich protoatmospheres.

    PubMed

    Lammer, Helmut; Kislyakova, K G; Odert, P; Leitzinger, M; Schwarz, R; Pilat-Lohinger, E; Kulikov, Yu N; Khodachenko, M L; Güdel, M; Hanslmeier, M

    2011-12-01

    We discuss the evolution of the atmosphere of early Earth and of terrestrial exoplanets which may be capable of sustaining liquid water oceans and continents where life may originate. The formation age of a terrestrial planet, its mass and size, as well as the lifetime in the EUV-saturated early phase of its host star play a significant role in its atmosphere evolution. We show that planets even in orbits within the habitable zone of their host stars might not lose nebular- or catastrophically outgassed initial protoatmospheres completely and could end up as water worlds with CO2 and hydrogen- or oxygen-rich upper atmospheres. If an atmosphere of a terrestrial planet evolves to an N2-rich atmosphere too early in its lifetime, the atmosphere may be lost. We show that the initial conditions set up by the formation of a terrestrial planet and by the evolution of the host star's EUV and plasma environment are very important factors owing to which a planet may evolve to a habitable world. Finally we present a method for studying the discussed atmosphere evolution hypotheses by future UV transit observations of terrestrial exoplanets.

  10. Atmospheric degradation mechanisms of hydrogen containing chlorofluorocarbons (HCFC) and fluorocarbons (HFC)

    NASA Technical Reports Server (NTRS)

    Zellner, Reinhard

    1990-01-01

    The current knowledge of atmospheric degradation of hydrogen containing chlorofluorocarbons (HCFC 22 (CHClF2), HCFC 123 (CHCl2CF3), HCFC 124 (CHClFCF3), HCFC 141b (CFCl2CH3), HCFC 142b (CF2ClCH3)) and fluorocarbons (HFC 125 (CHF2CF3), HFC 134a (CH2FCF3), HFC 152a (CHF2CH3)) is assessed. Except for the initiation reaction by OH radicals, there are virtually no experimental data available concerning the subsequent oxidative breakdown of these molecules. However, from an analogy to the degradation mechanisms of simple alkanes, some useful guidelines as to the expected intermediates and final products can be derived. A noteable exception from this analogy, however, appears for the oxi-radicals. Here, halogen substitution induces new reaction types (C-Cl and C-C bond ruptures) which are unknown to the unsubstituted analogues and which modify the nature of the expected carbonyl products. Based on an evaluation of these processes using estimated bond strength data, the following simplified rules with regards to the chlorine content of the HCFC's may be deduced: (1) HCFC's containing one chlorine atom such as 22 and 142b seem to release their chlorine content essentially instantaneous with the initial attack on the parent by OH radicals, and for HCFC 124, such release is apparently prevented; (2) HCFC's such as 123 and 141b with two chlorine atoms are expected to release only one of these instantaneously; and the second chlorine atom may be stored in potentially long-lived carbonyl compounds such as CF3CClO or CClFO.

  11. A new estimation of the recent tropospheric molecular hydrogen budget using atmospheric observations and variational inversion

    NASA Astrophysics Data System (ADS)

    Yver, C. E.; Pison, I. C.; Fortems-Cheiney, A.; Schmidt, M.; Chevallier, F.; Ramonet, M.; Jordan, A.; Søvde, O. A.; Engel, A.; Fisher, R. E.; Lowry, D.; Nisbet, E. G.; Levin, I.; Hammer, S.; Necki, J.; Bartyzel, J.; Reimann, S.; Vollmer, M. K.; Steinbacher, M.; Aalto, T.; Maione, M.; Arduini, J.; O'Doherty, S.; Grant, A.; Sturges, W. T.; Forster, G. L.; Lunder, C. R.; Privalov, V.; Paramonova, N.; Werner, A.; Bousquet, P.

    2011-04-01

    This paper presents an analysis of the recent tropospheric molecular hydrogen (H2) budget with a particular focus on soil uptake and European surface emissions. A variational inversion scheme is combined with observations from the RAMCES and EUROHYDROS atmospheric networks, which include continuous measurements performed between mid-2006 and mid-2009. Net H2 surface flux, then deposition velocity and surface emissions and finally, deposition velocity, biomass burning, anthropogenic and N2 fixation-related emissions were simultaneously inverted in several scenarios. These scenarios have focused on the sensibility of the soil uptake value to different spatio-temporal distributions. The range of variations of these diverse inversion sets generate an estimate of the uncertainty for each term of the H2 budget. The net H2 flux per region (High Northern Hemisphere, Tropics and High Southern Hemisphere) varies between -8 and +8 Tg yr-1. The best inversion in terms of fit to the observations combines updated prior surface emissions and a soil deposition velocity map that is based on bottom-up and top-down estimations. Our estimate of global H2 soil uptake is -59±9 Tg yr-1. Forty per cent of this uptake is located in the High Northern Hemisphere and 55% is located in the Tropics. In terms of surface emissions, seasonality is mainly driven by biomass burning emissions. The inferred European anthropogenic emissions are consistent with independent H2 emissions estimated using a H2/CO mass ratio of 0.034 and CO emissions within the range of their respective uncertainties. Additional constraints, such as isotopic measurements would be needed to infer a more robust partition of H2 sources and sinks.

  12. New porous water ice metastable at atmospheric pressure obtained by emptying a hydrogen-filled ice.

    PubMed

    Del Rosso, Leonardo; Celli, Milva; Ulivi, Lorenzo

    2016-11-07

    The properties of some forms of water ice reserve still intriguing surprises. Besides the several stable or metastable phases of pure ice, solid mixtures of water with gases are precursors of other ices, as in some cases they may be emptied, leaving a metastable hydrogen-bound water structure. We present here the first characterization of a new form of ice, obtained from the crystalline solid compound of water and molecular hydrogen called C0-structure filled ice. By means of Raman spectroscopy, we measure the hydrogen release at different temperatures and succeed in rapidly removing all the hydrogen molecules, obtaining a new form of ice (ice XVII). Its structure is determined by means of neutron diffraction measurements. Of paramount interest is that the emptied crystal can adsorb again hydrogen and release it repeatedly, showing a temperature-dependent hysteresis.

  13. New porous water ice metastable at atmospheric pressure obtained by emptying a hydrogen-filled ice

    NASA Astrophysics Data System (ADS)

    Del Rosso, Leonardo; Celli, Milva; Ulivi, Lorenzo

    2016-11-01

    The properties of some forms of water ice reserve still intriguing surprises. Besides the several stable or metastable phases of pure ice, solid mixtures of water with gases are precursors of other ices, as in some cases they may be emptied, leaving a metastable hydrogen-bound water structure. We present here the first characterization of a new form of ice, obtained from the crystalline solid compound of water and molecular hydrogen called C0-structure filled ice. By means of Raman spectroscopy, we measure the hydrogen release at different temperatures and succeed in rapidly removing all the hydrogen molecules, obtaining a new form of ice (ice XVII). Its structure is determined by means of neutron diffraction measurements. Of paramount interest is that the emptied crystal can adsorb again hydrogen and release it repeatedly, showing a temperature-dependent hysteresis.

  14. New porous water ice metastable at atmospheric pressure obtained by emptying a hydrogen-filled ice

    PubMed Central

    del Rosso, Leonardo; Celli, Milva; Ulivi, Lorenzo

    2016-01-01

    The properties of some forms of water ice reserve still intriguing surprises. Besides the several stable or metastable phases of pure ice, solid mixtures of water with gases are precursors of other ices, as in some cases they may be emptied, leaving a metastable hydrogen-bound water structure. We present here the first characterization of a new form of ice, obtained from the crystalline solid compound of water and molecular hydrogen called C0-structure filled ice. By means of Raman spectroscopy, we measure the hydrogen release at different temperatures and succeed in rapidly removing all the hydrogen molecules, obtaining a new form of ice (ice XVII). Its structure is determined by means of neutron diffraction measurements. Of paramount interest is that the emptied crystal can adsorb again hydrogen and release it repeatedly, showing a temperature-dependent hysteresis. PMID:27819265

  15. Hydrogen isotope composition of dry season atmospheric water vapor on Quelccaya Ice Cap, Peru

    NASA Astrophysics Data System (ADS)

    Samuels-Crow, K. E.; Galewsky, J.; Hardy, D. R.; Braun, C.

    2011-12-01

    In-situ measurements of modern meteorological conditions at Quelccaya Ice Cap's summit, including the isotopic composition of atmospheric water vapor, may aid in the interpretation of the 1500-year, annually resolved ice-core record available from the site (Thompson et al., 2003). Betweeen July 7 and July 9, 2011, we collected 11 samples of atmospheric water vapor from the summit of Quelccaya and analyzed the hydrogen isotopic composition on a Finnegan MAT-252 mass spectrometer using the method of Strong et al 2007. δD values ranged from -134% to -168%, and specific humidity ranged from 1.5 to 3 g/kg. The isotopic composition of tropical Andean ice cores has been variously interpreted in terms of simple Rayleigh distillation models, in which water evaporates from the tropical Atlantic and condenses as it moves upslope (Grootes et al., 1989; Pierrehumbert, 1999), or in terms of the condensation temperature (Thompson et al., 2003). The joint distribution of water vapor concentrations and δD values in our dataset cannot be explained by a simple upslope Rayleigh distillation model. Such a model predicts higher water-vapor concentrations and lower δD values than those measured during the sampling period. We hypothesize that the joint distribution of water vapor mixing ratio and isotopic composition can be explained by large-scale mixing of air parcels that were last saturated in the upper tropical troposphere. Such mixing necessarily leads to parcels that have higher delta values than would be expected for the simple Rayleigh distillation to the observed mixing ratio. Local effects of snow sublimation may exert additional controls over the water-vapor mixing ratio and delta values. Further monitoring during both the wet and dry seasons may clarify the relationship between large-scale water-vapor transport and the snow and ice preserved on Quelccaya. References Friedman, I. (1953) Deuterium content of natural waters and other substances, Geoch. et Cosmochim. Acta, 4

  16. Functionalization of Hydrogen-free Diamond-like Carbon Films using Open-air Dielectric Barrier Discharge Atmospheric Plasma Treatments

    SciTech Connect

    Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Instituto de Materiales de Madrid, C.S.I.C., Cantoblanco, 28049 Madrid, Spain; Instituto de Quimica-Fisica"Rocasolano"C.S.I.C., 28006 Madrid, Spain; Mahasarakham University, Mahasarakham 44150, Thailand; CASTI, CNR-INFM Regional Laboratory, L'Aquila 67100, Italy; SUNY Upstate Medical University, Syracuse, NY 13210, USA; Endrino, Jose; Endrino, J. L.; Marco, J. F.; Poolcharuansin, P.; Phani, A.R.; Allen, M.; Albella, J. M.; Anders, A.

    2007-12-28

    A dielectric barrier discharge (DBD) technique has been employed to produce uniform atmospheric plasmas of He and N2 gas mixtures in open air in order to functionalize the surface of filtered-arc deposited hydrogen-free diamond-like carbon (DLC) films. XPS measurements were carried out on both untreated and He/N2 DBD plasma treated DLC surfaces. Chemical states of the C 1s and N 1s peaks were collected and used to characterize the surface bonds. Contact angle measurements were also used to record the short- and long-term variations in wettability of treated and untreated DLC. In addition, cell viability tests were performed to determine the influence of various He/N2 atmospheric plasma treatments on the attachment of osteoblast MC3T3 cells. Current evidence shows the feasibility of atmospheric plasmas in producing long-lasting variations in the surface bonding and surface energy of hydrogen-free DLC and consequently the potential for this technique in the functionalization of DLC coated devices.

  17. The constitution of the atmospheric layers and the extreme ultraviolet spectrum of hot hydrogen-rich white dwarfs

    NASA Technical Reports Server (NTRS)

    Vennes, Stephane

    1992-01-01

    An analysis is presented of the atmospheric properties of hot, H-rich, DA white dwarfs that is based on optical, UV, and X-ray observations aimed at predicting detailed spectral properties of these stars in the range 80-800 A. The divergences between observations from a sample of 15 hot DA white dwarfs emitting in the EUV/soft X-ray range and pure H synthetic spectra calculated from a grid of model atmospheres characterized by Teff and g are examined. Seven out of 15 DA stars are found to consistently exhibit pure hydrogen atmospheres, the remaining seven stars showing inconsistency between FUV and EUV/soft X-ray data that can be explained by the presence of trace EUV/soft X-ray absorbers. Synthetic data are computed assuming two other possible chemical structures: photospheric traces of radiatively levitated heavy elements and a stratified hydrogen/helium distribution. Predictions about forthcoming medium-resolution observations of the EUV spectrum of selected hot H-rich white dwarfs are made.

  18. Ground-based Infrared Observations of Water Vapor and Hydrogen Peroxide in the Atmosphere of Mars

    NASA Astrophysics Data System (ADS)

    Encrenaz, T.; Greathouse, T. K.; Bitner, M.; Kruger, A.; Richter, M. J.; Lacy, J. H.; Bézard, B.; Fouchet, T.; Lefevre, F.; Forget, F.; Atreya, S. K.

    2008-11-01

    Ground-based observations of water vapor and hydrogen peroxide have been obtained in the thermal infrared range, using the TEXES instrument at the NASA Infrared Telescope Facility, for different times of the seasonal cycle.

  19. Gaseous toroid around Saturn. [Saturnian ring system for atomic hydrogen trapping in Titan atmospheric model

    NASA Technical Reports Server (NTRS)

    Mcdonough, T. R.

    1974-01-01

    The trapping of Titan's escaping atmosphere in the Saturnian system by a toroidal ring is discussed. The radius of the toroid is comparable to Titan's orbit, or about ten times larger than the visible rings. Theoretical atmospheric models are formulated that consider Saturn's gravitational attraction and magnetospheric properties in forming this toroid and in protecting toroid particles from direct ionization by solar wind particles.

  20. Microstructural evolution of Cu-1at% Ti alloy aged in a hydrogen atmosphere and its relation with the electrical conductivity.

    PubMed

    Semboshi, Satoshi; Al-Kassab, Talaat; Gemma, Ryota; Kirchheim, Reiner

    2009-04-01

    Copper alloys with titanium additions between 1 and 6at% Ti emerge currently as attractive conductive materials for electrical and electronic commercial products, since they exhibit superior mechanical and electrical properties. However, their electrical conductivity is reduced owing to the residual amount of Ti solutes in the Cu solid solution (Cu(ss)) phase. Since Cu shows only poor reactivity with hydrogen (H), while Ti exhibits high affinity to it, we were inspired by the idea that hydrogenation of Cu-Ti alloys would influence their microstructure, resulting in a significant change of their properties. In this contribution, the influence of aging under a deuterium (D(2)) atmosphere of Cu-1at% Ti alloys on their microstructure is investigated to explore the effects on the electrical conductivity. The specimens were investigated by means of transmission electron microscopy (TEM), field ion microscopy (FIM), computer-aided field ion image tomography (cFIIT), and atom probe tomography (APT). At an early aging stage at 623K in a D(2) atmosphere of 0.08MPa, ellipsoidal alpha-Cu(4)Ti precipitates are formed in the alloy, and during subsequent aging, delta-TiD(2) is competitively nucleated instead of growth of alpha-Cu(4)Ti particles. The co-precipitation of alpha-Cu(4)Ti and delta-TiD(2) efficiently reduces the Ti concentration of Cu(ss) matrix, particularly in the later aging stages in comparison to the aging in vacuum conditions. The electrical conductivity of the alloy aged in the D(2) atmosphere increases steeply up to 48% International Annealed Copper Standard (IACS) after 1030h, while it saturates to approximately 20% IACS in the alloy aged in vacuum. The outstanding increase of electrical conductivity during aging in D(2) atmosphere can be basically explained by the reduction of Ti solute concentration in Cu(ss) matrix.

  1. Copper dry etching by sub-atmospheric-pressure pure hydrogen glow plasma

    NASA Astrophysics Data System (ADS)

    Ohmi, Hiromasa; Sato, Jumpei; Hirano, Tatsuya; Kubota, Yusuke; Kakiuchi, Hiroaki; Yasutake, Kiyoshi

    2016-11-01

    Copper (Cu) dry etching is demonstrated using a narrow-gap hydrogen plasma generated at 13.3 kPa (100 Torr) for applications in the Cu wiring technology of integrated circuits. A localized hydrogen plasma is generated around the apex of a fine pipe electrode. The Cu etching can be observed only when the process gas contains hydrogen, and the etching rates decrease with decreased hydrogen concentration. The plasma heating effect owing to plasma localization is negligible for the Cu etching because no etching occurs in the presence of pure N2 plasma whose volume is almost equal to that of the pure H2 plasma. Furthermore, the influences of physical sputtering and vacuum ultraviolet irradiation on the Cu etching are confirmed to be insignificant by exposing the samples to rare-gas plasma. The maximum Cu etching rate of 500 nm/min can be achieved at a stage temperature of 0 °C. However, the Cu etching rate has no obvious dependence on the stage temperature in a range from -20 to 330 °C. In contrast, the etching rates for Si and SiO2 at a stage temperature of 0 °C are 100 μm/min and 50 nm/min, respectively. The Cu etching rate is 10 times higher than that of SiO2, which implies that this etching technique has potential applications for Cu wiring on an SiO2 layer. The Cu surface etched by the hydrogen plasma is roughened and exhibits many round pits and bumps, which seems to be owing to excessive incorporation of the diffused hydrogen in the Cu bulk.

  2. Titan's atmosphere: Comments on haze content, methane abundance, band shapes, and hydrogen upper limit

    NASA Technical Reports Server (NTRS)

    Trafton, L.

    1978-01-01

    The existence of scatterers in Titan's atmosphere was demonstrated in a paper published in the Astrophysical Journal three years ago. This conclusion was not affected by recent laboratory investigations showing that certain CH4 bands are independent of pressure because it was shown that the reflecting layer model failed to explain Titan's CH4 absorptions regardless on which portion of the curve of growth Titan's CH4 lines lie. Saturn's atmosphere was utilized along the central meridian for studies of CH4 absorption, and to show that the conclusion is insensitive to the moderate scattering there. The quite pronounced role of scattering in Titan's atmosphere strongly suggests that Titan's surface is obscured.

  3. Monitoring of Atmospheric Hydrogen Peroxide in Houston Using Long Path-Length Laser-Based Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sanchez, N. P.; Cao, Y.; Jiang, W.; Tittel, F. K.; Griffin, R. J.

    2014-12-01

    Hydrogen peroxide (H2O2) is a relevant atmospheric species mainly formed by recombination of hydroperoxyl radicals. H2O2 participates in the formation of sulfate aerosol by in-cloud oxidation of S(IV) to S(VI) and has been associated with the generation of multi-functional water soluble organic compounds in atmospheric particulate matter. Furthermore, H2O2 plays an important role in the oxidative capacity of the atmosphere as it acts as a reservoir for HOx radicals (OH and HO2). Particular conditions in the Houston area (e.g. extensive presence of petrochemical industry and high ozone and humidity levels) indicate the potential relevance of this species at this location. Despite its atmospheric relevance, no reports on the levels of H2O2 in Houston have been presented previously in the scientific literature. Determination of atmospheric H2O2 usually has been conducted based on transfer of the gas-phase H2O2 to the liquid phase prior to quantification by techniques such as fluorescence spectroscopy. Although these methods allow detection of H2O2 at the sub-ppb level, they present some limitations including the interference from other atmospheric constituents and potential sampling artifacts. In this study, a high sensitivity sensor based on long-path absorption spectroscopy using a distributed-feedback quantum cascade laser was developed and used to conduct direct gas-phase H2O2 monitoring in Houston. The sensor, which targets a strong H2O2 absorption line (~7.73 μm) with no interference from other atmospheric species, was deployed at a ground level monitoring station near the University of Houston main campus during summer 2014. The performance of this novel sensor was evaluated by side-by-side comparison with a fluorescence-based instrument typically used for atmospheric monitoring of H2O2. H2O2 levels were determined, and time series of H2O2 mixing ratios were generated allowing insight into the dynamics, trends, and atmospheric inter-relations of H2O2 in the

  4. Novel atmospheric pressure plasma device releasing atomic hydrogen: reduction of microbial-contaminants and OH radicals in the air

    NASA Astrophysics Data System (ADS)

    Nojima, Hideo; Park, Rae-Eun; Kwon, Jun-Hyoun; Suh, Inseon; Jeon, Junsang; Ha, Eunju; On, Hyeon-Ki; Kim, Hye-Ryung; Choi, Kyoung Hui; Lee, Kwang-Hee; Seong, Baik-Lin; Jung, Hoon; Kang, Shin Jung; Namba, Shinichi; Takiyama, Ken

    2007-01-01

    A novel atmospheric pressure plasma device releasing atomic hydrogen has been developed. This device has specific properties such as (1) deactivation of airborne microbial-contaminants, (2) neutralization of indoor OH radicals and (3) being harmless to the human body. It consists of a ceramic plate as a positive ion generation electrode and a needle-shaped electrode as an electron emission electrode. Release of atomic hydrogen from the device has been investigated by the spectroscopic method. Optical emission of atomic hydrogen probably due to recombination of positive ions, H+(H2O)n, generated from the ceramic plate electrode and electrons emitted from the needle-shaped electrode have been clearly observed in the He gas (including water vapour) environment. The efficacy of the device to reduce airborne concentrations of influenza virus, bacteria, mould fungi and allergens has been evaluated. 99.6% of airborne influenza virus has been deactivated with the operation of the device compared with the control test in a 1 m3 chamber after 60 min. The neutralization of the OH radical has been investigated by spectroscopic and biological methods. A remarkable reduction of the OH radical in the air by operation of the device has been observed by laser-induced fluorescence spectroscopy. The cell protection effects of the device against OH radicals in the air have been observed. Furthermore, the side effects have been checked by animal experiments. The harmlessness of the device has been confirmed.

  5. Production of hydrogen peroxide in the atmosphere of a Snowball Earth and the origin of oxygenic photosynthesis.

    PubMed

    Liang, Mao-Chang; Hartman, Hyman; Kopp, Robert E; Kirschvink, Joseph L; Yung, Yuk L

    2006-12-12

    During Proterozoic time, Earth experienced two intervals with one or more episodes of low-latitude glaciation, which are probable "Snowball Earth" events. Although the severity of the historical glaciations is debated, theoretical "hard Snowball" conditions are associated with the nearly complete shutdown of the hydrological cycle. We show here that, during such long and severe glacial intervals, a weak hydrological cycle coupled with photochemical reactions involving water vapor would give rise to the sustained production of hydrogen peroxide. The photochemical production of hydrogen peroxide has been proposed previously as the primary mechanism for oxidizing the surface of Mars. During a Snowball, hydrogen peroxide could be stored in the ice; it would then be released directly into the ocean and the atmosphere upon melting and could mediate global oxidation events in the aftermath of the Snowball, such as that recorded in the Fe and Mn oxides of the Kalahari Manganese Field, deposited after the Paleoproterozoic low-latitude Makganyene glaciation. Low levels of peroxides and molecular oxygen generated during Archean and earliest Proterozoic non-Snowball glacial intervals could have driven the evolution of oxygen-mediating and -using enzymes and thereby paved the way for the eventual appearance of oxygenic photosynthesis.

  6. Massive release of hydrogen sulfide to the surface ocean and atmosphere during intervals of oceanic anoxia

    NASA Astrophysics Data System (ADS)

    Kump, Lee R.; Pavlov, Alexander; Arthur, Michael A.

    2005-05-01

    Simple calculations show that if deep-water H2S concentrations increased beyond a critical threshold during oceanic anoxic intervals of Earth history, the chemocline separating sulfidic deep waters from oxygenated surface waters could have risen abruptly to the ocean surface (a chemocline upward excursion). Atmospheric photochemical modeling indicates that resulting fluxes of H2S to the atmosphere (>2000 times the small modern flux from volcanoes) would likely have led to toxic levels of H2S in the atmosphere. Moreover, the ozone shield would have been destroyed, and methane levels would have risen to >100 ppm. We thus propose (1) chemocline upward excursion as a kill mechanism during the end-Permian, Late Devonian, and Cenomanian Turonian extinctions, and (2) persistently high atmospheric H2S levels as a factor that impeded evolution of eukaryotic life on land during the Proterozoic.

  7. Annealing of GaSb Single Crystals in Ionised Hydrogen Atmosphere

    DTIC Science & Technology

    2001-01-01

    and Applications 46 of Single Crystals, Antoni Rogaski, Krzysztof Adamiec, Pawel Madejczyk, Editors, Proceedings of SPIE Vol. 4412 (2001) © 2001...1-50 hours. Hydrogen ionised by means of a deuterium lamp flew through this annealing reactor. After cooling the quartz ampoule, the carrier

  8. Comparing 3D Solar Model Atmospheres with Observations: Hydrogen Lines and Centre-to-limb Variations

    NASA Astrophysics Data System (ADS)

    Pereira, Tiago M. D.; Asplund, Martin; Trampedach, Regner

    Three dimensional hydrodynamical stellar model atmospheres represent a major step forward in stellar spectroscopy. Making use of radiative-hydrodynamical convection simulations that contain no adjustable free parameters, the model atmospheres provide a robust and realistic treatment of convection. These models have been applied to several lines in the Sun and other stars, yielding an excellent agreement with observations (e.g., Asplund et al. (2000) [1]).

  9. Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

    NASA Astrophysics Data System (ADS)

    Gorski, Galen; Strong, Courtenay; Good, Stephen P.; Bares, Ryan; Ehleringer, James R.; Bowen, Gabriel J.

    2015-03-01

    Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. We show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration of water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. Our findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry.

  10. Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

    PubMed Central

    Gorski, Galen; Strong, Courtenay; Good, Stephen P.; Bares, Ryan; Ehleringer, James R.; Bowen, Gabriel J.

    2015-01-01

    Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. We show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration of water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. Our findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry. PMID:25733906

  11. The quenching effect of hydrogen on the nitrogen in metastable state in atmospheric-pressure N{sub 2}-H{sub 2} microwave plasma torch

    SciTech Connect

    Li, Shou-Zhe Zhang, Xin; Chen, Chuan-Jie; Zhang, Jialiang; Wang, Yong-Xing; Xia, Guang-Qing

    2014-07-15

    The atmospheric-pressure microwave N{sub 2}-H{sub 2} plasma torch is generated and diagnosed by optical emission spectroscopy. It is found that a large amount of N atoms and NH radicals are generated in the plasma torch and the emission intensity of N{sub 2}{sup +} first negative band is the strongest over the spectra. The mixture of hydrogen in nitrogen plasma torch causes the morphology of the plasma discharge to change with appearance that the afterglow shrinks greatly and the emission intensity of N{sub 2}{sup +} first negative band decreases with more hydrogen mixed into nitrogen plasma. In atmospheric-pressure microwave-induced plasma torch, the hydrogen imposes a great influence on the characteristics of nitrogen plasma through the quenching effect of the hydrogen on the metastable state of N{sub 2}.

  12. EUV-driven mass-loss of protoplanetary cores with hydrogen-dominated atmospheres: the influences of ionization and orbital distance

    NASA Astrophysics Data System (ADS)

    Erkaev, N. V.; Lammer, H.; Odert, P.; Kislyakova, K. G.; Johnstone, C. P.; Güdel, M.; Khodachenko, M. L.

    2016-08-01

    We investigate the loss rates of the hydrogen atmospheres of terrestrial planets with a range of masses and orbital distances by assuming a stellar extreme ultraviolet (EUV) luminosity that is 100 times stronger than that of the current Sun. We apply a 1D upper atmosphere radiation absorption and hydrodynamic escape model that takes into account ionization, dissociation and recombination to calculate hydrogen mass-loss rates. We study the effects of the ionization, dissociation and recombination on the thermal mass-loss rates of hydrogen-dominated super-Earths and compare the results to those obtained by the energy-limited escape formula which is widely used for mass-loss evolution studies. Our results indicate that the energy-limited formula can to a great extent over- or underestimate the hydrogen mass-loss rates by amounts that depend on the stellar EUV flux and planetary parameters such as mass, size, effective temperature and EUV absorption radius.

  13. Hydrogen Isotopes Record the History of the Martian Hydrosphere and Atmosphere

    NASA Technical Reports Server (NTRS)

    Usui, T.; Simon, J. I.; Jones, J. H.; Kurokawa, H.; Sato, M.; Alexander, C. M. O'D; Wang, J.

    2015-01-01

    The surface geology and geomorphology of Mars indicates that it was once warm enough to maintain a large body of liquid water on its surface, though such a warm environment might have been transient. The transition to the present cold and dry Mars is closely linked to the history of surface water, yet the evolution of surficial water is poorly constrained. This study presents insights from hydrogen isotopes for the origin and evolution of Martian water reservoirs.

  14. Supercritical fluid chromatography coupled with in-source atmospheric pressure ionization hydrogen/deuterium exchange mass spectrometry for compound speciation.

    PubMed

    Cho, Yunju; Choi, Man-Ho; Kim, Byungjoo; Kim, Sunghwan

    2016-04-29

    An experimental setup for the speciation of compounds by hydrogen/deuterium exchange (HDX) with atmospheric pressure ionization while performing chromatographic separation is presented. The proposed experimental setup combines the high performance supercritical fluid chromatography (SFC) system that can be readily used as an inlet for mass spectrometry (MS) and atmospheric pressure photo ionization (APPI) or atmospheric pressure chemical ionization (APCI) HDX. This combination overcomes the limitation of an approach using conventional liquid chromatography (LC) by minimizing the amount of deuterium solvents used for separation. In the SFC separation, supercritical CO2 was used as a major component of the mobile phase, and methanol was used as a minor co-solvent. By using deuterated methanol (CH3OD), AP HDX was achieved during SFC separation. To prove the concept, thirty one nitrogen- and/or oxygen-containing standard compounds were analyzed by SFC-AP HDX MS. The compounds were successfully speciated from the obtained SFC-MS spectra. The exchange ions were observed with as low as 1% of CH3OD in the mobile phase, and separation could be performed within approximately 20min using approximately 0.24 mL of CH3OD. The results showed that SFC separation and APPI/APCI HDX could be successfully performed using the suggested method.

  15. Hydrogen Peroxide and Methylhydroperoxide Budgets in the Marine Boundary Layer During the Pacific Atmospheric Sulfur Experiment

    NASA Astrophysics Data System (ADS)

    O'Sullivan, D. W.; Heikes, B. G.; Higbie, A.; Merrill, J. T.; Bandy, A. R.; Mauldin, L.; Cantrell, C.; Anderson, R. S.; Campos, T.; Lenschow, D.; Bloomquist, B.; Faloona, I. C.; Conley, S. A.; Wang, Y.; Pollack, I. B.; Heizer, C. G.; Weinheimer, A. J.

    2008-12-01

    Airborne gas phase measurements of hydrogen peroxide, methylhydroperoxide, ozone, carbon monoxide, dimethylsulfide, sulfur dioxide, hydroxyl, and perhydroxyl, together with meteorological parameters are used to assess the photochemical budget of hydrogen peroxide and methylhydroperoxide in the marine boundary layer (MBL). The observations come from 14 research flights using the NCAR C-130 flown mostly southeast of Kiritimati in relatively cloud- and precipitation-free MBL air. This region was expected to have extremely low nitrogen oxide mixing ratios and minimal horizontal gradients in composition. Eddy-correlation methods are used to estimate entrainment rates at the top of the MBL. Surface deposition rates are calculated from wind and molecular properties. Gas phase photolysis rates are calculated and reaction rate constants are estimated from the literature. The measurements and budgets are discussed in terms of their ability to constrain net ozone production, nitrogen oxide levels, reactive hydrocarbons, and halogen radical chemistry. On occasion the aircraft flew within its advected exhaust plume and a decrease in methylhydroperoxide, but not in hydrogen peroxide, was noted.

  16. Effects of residual hydrogen in sputtering atmosphere on structures and properties of amorphous In-Ga-Zn-O thin films

    SciTech Connect

    Tang, Haochun; Ishikawa, Kyohei; Ide, Keisuke; Hiramatsu, Hidenori; Hosono, Hideo; Kamiya, Toshio; Ueda, Shigenori; Ohashi, Naoki; Kumomi, Hideya

    2015-11-28

    We investigated the effects of residual hydrogen in sputtering atmosphere on subgap states and carrier transport in amorphous In-Ga-Zn-O (a-IGZO) using two sputtering systems with different base pressures of ∼10{sup −4} and 10{sup −7 }Pa (standard (STD) and ultrahigh vacuum (UHV) sputtering, respectively), which produce a-IGZO films with impurity hydrogen contents at the orders of 10{sup 20} and 10{sup 19 }cm{sup −3}, respectively. Several subgap states were observed by hard X-ray photoemission spectroscopy, i.e., peak-shape near-valence band maximum (near-VBM) states, shoulder-shape near-VBM states, peak-shape near-conduction band minimum (near-CBM) states, and step-wise near-CBM states. It was confirmed that the formation of these subgap states were affected strongly by the residual hydrogen (possibly H{sub 2}O). The step-wise near-CBM states were observed only in the STD films deposited without O{sub 2} gas flow and attributed to metallic In. Such step-wise near-CBM state was not detected in the other films including the UHV films even deposited without O{sub 2} flow, substantiating that the metallic In is segregated by the strong reduction effect of the hydrogen/H{sub 2}O. Similarly, the density of the near-VBM states was very high for the STD films deposited without O{sub 2}. These films had low film density and are consistent with a model that voids in the amorphous structure form a part of the near-VBM states. On the other hand, the UHV films had high film densities and much less near-VBM states, keeping the possibility that some of the near-VBM states, in particular, of the peak-shape ones, originate from –OH and weakly bonded oxygen. These results indicate that 2% of excess O{sub 2} flow is required for the STD sputtering to compensate the effects of the residual hydrogen/H{sub 2}O. The high-density near-VBM states and the metallic In segregation deteriorated the electron mobility to 0.4 cm{sup 2}/(V s)

  17. Statistically advanced, self-similar, radial probability density functions of atmospheric and under-expanded hydrogen jets

    NASA Astrophysics Data System (ADS)

    Ruggles, Adam J.

    2015-11-01

    This paper presents improved statistical insight regarding the self-similar scalar mixing process of atmospheric hydrogen jets and the downstream region of under-expanded hydrogen jets. Quantitative planar laser Rayleigh scattering imaging is used to probe both jets. The self-similarity of statistical moments up to the sixth order (beyond the literature established second order) is documented in both cases. This is achieved using a novel self-similar normalization method that facilitated a degree of statistical convergence that is typically limited to continuous, point-based measurements. This demonstrates that image-based measurements of a limited number of samples can be used for self-similar scalar mixing studies. Both jets exhibit the same radial trends of these moments demonstrating that advanced atmospheric self-similarity can be applied in the analysis of under-expanded jets. Self-similar histograms away from the centerline are shown to be the combination of two distributions. The first is attributed to turbulent mixing. The second, a symmetric Poisson-type distribution centered on zero mass fraction, progressively becomes the dominant and eventually sole distribution at the edge of the jet. This distribution is attributed to shot noise-affected pure air measurements, rather than a diffusive superlayer at the jet boundary. This conclusion is reached after a rigorous measurement uncertainty analysis and inspection of pure air data collected with each hydrogen data set. A threshold based upon the measurement noise analysis is used to separate the turbulent and pure air data, and thusly estimate intermittency. Beta-distributions (four parameters) are used to accurately represent the turbulent distribution moments. This combination of measured intermittency and four-parameter beta-distributions constitutes a new, simple approach to model scalar mixing. Comparisons between global moments from the data and moments calculated using the proposed model show excellent

  18. Hydrogen shift reactions in four methyl-buten-ol (MBO) peroxy radicals and their impact on the atmosphere

    NASA Astrophysics Data System (ADS)

    Knap, Hasse C.; Schmidt, Johan A.; Jørgensen, Solvejg

    2016-12-01

    We investigate the hydrogen shift (H-shift) reactions in the peroxy radicals derived from four different methyl-buten-ol (MBO) molecules; 2-methyl-3-buten-2-ol (MBO232), 2-methyl-3-buten-1-ol (MBO231), 3-Methyl-3-buten-2-ol (MBO332) and 3-methyl-3-buten-1-ol (MBO331), with quantum mechanical calculations. The rate constants of the 1,5 H-shift reactions in all four MBO peroxy radicals are greater than the rate constants of the 1,4 or 1,6 H-shift reactions. The rate constants for the 1,5 H-shift reaction from either a CH group or an OH group are approximately 1 s-1 and 10-3 s-1, respectively. The atmospheric impact of the MBO232 oxidation is investigated with the global chemical transport model (GEOS-Chem). The 1,4-CH and 1,5-OH H-shift reactions in the MBO232 peroxy radical play a minor role with a total yield of about 2%. The major atmospheric reactions of the MBO232 peroxy radical are the reactions with NO and HO2, with reaction yield of 85% and 13%, respectively.

  19. Effects of Two Large Solar Energetic Particle Events on Middle Atmosphere Nighttime Odd Hydrogen and Ozone Content

    NASA Astrophysics Data System (ADS)

    Verkhoglyadova, O. P.; Butala, M.; Wang, S.; Mlynczak, M. G.; Hunt, L. A.; Zank, G. P.

    2014-12-01

    We analyze global middle atmospheric (~60 to 90 km) effects at local nighttime for two large Solar Energetic Particle (SEP) events that occurred during intervals of 7-17 November 2004 and 20-30 August 2005. Properties of the SEP events and concomitant geomagnetic storms are discussed using in situ measurements at 1 AU. Temporal dynamics and latitudinal distribution of odd hydrogen and ozone densities inferred from measurements by the AURA/MLS (Microwave Limb Sounder) instrument are analyzed. We show statistically significant increases of nightime hydroxyl (OH) density in the middle atmosphere up to 5•106 cm-3 in the latitude range from 70° down to 50° latitude in both northern and southern hemispheres in connection with peaks in proton fluxes of >10 MeV energy range measured by the GOES spacecraft. During storm main phases the nighttime hydroxyl density increases were observed at ±50° and above. The altitude range where these effects are observed (65-80 km) is consistent with precipitating protons of >4 MeV energy range. There is a correspondence between averaged nighttime OH density in the polar latitudes and 65-85 km altitude range, and energetic proton (>10 MeV) fluxes. Corresponding statistically significant nighttime ozone depletions up to 40% relative to the background values are observed from 70° down to 60° latitude in northern and southern hemispheres. Simultaneous measurements of ozone density by TIMED/SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) instrument independently confirm that major nighttime ozone density depletions occurred in the altitude range of 65-75 km and down to ±50° latitude during strong geomagnetic storms. The SEP impulsive phases on November 8-9th 2004 and August 23rd -25th 2005 correspond to onsets of ozone density depletions. Larger relative ozone depletions are observed in the northern hemisphere in November and in the southern hemisphere in August.

  20. Hydrogen Atom Collision Processes in Cool Stellar Atmospheres: Effects on Spectral Line Strengths and Measured Chemical Abundances in Old Stars

    NASA Astrophysics Data System (ADS)

    Barklem, Paul S.

    2012-12-01

    The precise measurement of the chemical composition of stars is a fundamental problem relevant to many areas of astrophysics. State-of-the-art approaches attempt to unite accurate descriptions of microphysics, non-local thermodynamic equilibrium (non-LTE) line formation and 3D hydrodynamical model atmospheres. In this paper I review progress in understanding inelastic collisions of hydrogen atoms with other species and their influence on spectral line formation and derived abundances in stellar atmospheres. These collisions are a major source of uncertainty in non-LTE modelling of spectral lines and abundance determinations, especially for old, metal-poor stars, which are unique tracers of the early evolution of our galaxy. Full quantum scattering calculations of direct excitation processes X(nl) + H leftrightarrow X(n'l') + H and charge transfer processes X(nl) + H leftrightarrow X+ + H- have been done for Li, Na and Mg [1,2,3] based on detailed quantum chemical data, e.g. [4]. Rate coefficients have been calculated and applied to non-LTE modelling of spectral lines in stellar atmospheres [5,6,7,8,9]. In all cases we find that charge transfer processes from the first excited S-state are very important, and the processes affect measured abundances for Li, Na and Mg in some stars by as much as 60%. Effects vary with stellar parameters (e.g. temperature, luminosity, metal content) and so these processes are important not only for accurate absolute abundances, but also for relative abundances among dissimilar stars.

  1. Sampler-sensor for preconcentration and quantitation of atmospheric hydrogen sulfide

    SciTech Connect

    LaRue, R.; Ataman, O.Y.; Hautman, D.P.; Gerhardt, G.; Zimmer, H.; Mark, H.B. Jr.

    1987-09-15

    Increasing concern over atmospheric environmental problems has necessitated the design and development of new analytical techniques in order to introduce alternatives to the presently employed methods. The use of solid sorbents for collection of pollutants in air has gained general acceptance, and criteria for this type of system have often been presented. In general practice, solid sorbents are subjected to a desorption process in order to prepare an analyte solution prior to an analytical detection procedure of choice. Therefore, in general, the solid sorbents employed are designed to provide physical and chemical characteristics for efficient takeup of analyte and yet allow effective desorption procedures. This results in a high overall recovery value necessary for required accuracy. Collection of atmospheric H/sub 2/S on a Cd(II)-exchanged zeolite as a solid sorbent and application of several analytical techniques as diverse as X-ray fluorescence spectrometry, combustion analysis by nondispersive infrared (IR) measurement, diffuse reflectance Fourier transform infrared (FTIR) spectrometry, visible spectrometry, and photoacoustic spectrometry on both intact solid sorbent and its leached solution after conversion to methylene blue have been studied. The present paper reports the initial data on a novel sampler-sensor that uses a filter paper pretreated system as a solid sorbent sampler having an air channel in the shape of a planar spiral which gives a direct visual readout of low levels of H/sub 2/S.

  2. Termites: a potentially large source of atmospheric methane, carbon dioxide, and molecular hydrogen

    SciTech Connect

    Zimmerman, P.R.; Greenberg, J.P.; Wandiga, S.O.; Crutzen, P.J.

    1982-11-01

    Termites are emitting large quantities of CH/sub 4/, CO/sub 2/, and H/sub 2/ into the atmosphere, especially in cleared tropical forest areas. Researchers estimate that these annual global emissions could amount to 0.3 trillion lb of CH/sub 4/, 11 trillion lb of CO/sub 2/ (more than twice the net global input from fossil-fuel combustion), and 0.4 trillion lb of H/sub 2/. However, they stress that because of many uncertainties, the acutal production of these gases could vary by a factor of two; i.e., methane production could range from 0.2 to 0.7 trillion lb. Occurring on about two-thirds of the earth's

  3. Infrared spectroscopy of acetylene, carbon monoxide, and deuterated hydrogen cyanide for planetary atmospheric applications

    NASA Astrophysics Data System (ADS)

    Esteki, Koorosh

    I present the results of three spectroscopic projects. First, we analysed spectra of acetylene diluted by carbon dioxide (CO2) in the R-branch region of the nu1+nu3 combination vibrational band (6470-6618 cm-1). The spectra were recorded over a range of pressures between 50 to 500 Torr and temperatures between 216 to 333 K. The objective was to obtain the CO2 broadened Lorentz half width, line-shift parameters as well as their temperature dependency for all measurable transitions. Second, we have re-analyzed high-resolution, room temperature spectra of pure CO and CO broadened by hydrogen recorded in the spectral range of the first overtone band. Self- and H2-broadened line parameters were obtained for 48 ro-vibrational transitions. Third, we studied the infrared emission spectra of Deuterium Cyanide (DCN) in the 450 to 850 wavenumbers range, recorded at 1370 K at the Justus-Liebig University, Giessen, Germany. We report the ro-vibrational constants for the DCN molecule.

  4. Modeling cloud effects on hydrogen peroxide and methylhydroperoxide in the marine atmosphere

    NASA Astrophysics Data System (ADS)

    Kim, Cheol-Hee; Kreidenweis, Sonia M.; Feingold, Graham; Frost, Gregory J.; Trainer, Michael K.

    2002-01-01

    Hydrogen peroxide (H2O2) and methylhydroperoxide (CH3OOH) are studied with a coupled gas phase and aqueous phase chemical model representing a remote nonprecipitating cloudy boundary layer. Cloud interactions may deplete or enhance H2O2 but have a minor effect on CH3OOH. Therefore two primary questions are addressed: (1) do nonprecipitating clouds perturb the ratio of H2O2/CH3OOH, and if so, (2) what is the rate of reestablishment of this ratio to clear-sky levels following cloud contact. The results show that the rate of recovery of the ratio of H2O2 to Ch3OOH after perturbation by cloud interactions depends on NOx (=NO + NO2) mixing ratios and on the time of day that cloud is encountered. When cloud contact is followed by a significant period of daylight, recovery to precloud values is rapid; however, when cloud contact occurs during the late afternoon or night, recovery can take up to 24 hours under high NOx conditions. Sensitivity tests show that in-cloud heterogeneous conversion of HNO3 to aerosol has a small but detectable effect (~10%) on the recovery of the ratio. Neglecting dry deposition of H2O2 and HNO3 increases the predicted ratio H2O2/CH3OOH in clear air prior to cloud contact, and has a small effect on the relative recovery rate of the ratio. In-cloud consumption of H2O2 by SO2 suppresses the postcloud ratio by ~40% relative to that in the base case for low levels of SO2 (~200 ppt), with a more pronounced effect on the ratio and its rate of recovery for [SO2] ~1 ppb. Because of the uncertainties associated with measurement of peroxides, and the dependence of the recovery of the ratio on the time of cloud contact, it is suggested that measurements of the ratio be considered judiciously and that they may not be of broad utility in predicting recent cloud contact.

  5. The Atmospheric Distribution of Molecular Hydrogen (H2) and Related Species During HIPPO and Other Recent Airborne Missions

    NASA Astrophysics Data System (ADS)

    Hintsa, E. J.; Moore, F. L.; Dutton, G. S.; Hall, B. D.; Nance, J. D.; Hurst, D. F.; Novelli, P. C.; Elkins, J. W.; Daube, B.; Kort, E. A.; Pittman, J. V.; Santoni, G. W.; Wofsy, S. C.; Jaegle, L.

    2012-12-01

    focus here is on the distribution of molecular hydrogen (H2), which has a diverse set of atmospheric and terrestrial sources, and a sink term that is dominated by soil uptake. The data show a slight maximum in the southern hemisphere and much greater variability with altitude in the northern hemisphere, broadly consistent with previous studies. Results from the GEOS-Chem model will be presented to allow greater insight into the distribution of H2 and related molecules. Tracer-tracer correlation plots of H2 with methane and CO will also be used to examine the details of the H2 distribution. HIPPO results show a local maximum in H2 at northern hemisphere midlatitudes in spring and early summer, and persistent low values of hydrogen at high northern latitudes long after the soil sink should have decreased with the onset of winter.

  6. Strong Hydrogen Bonded Molecular Interactions between Atmospheric Diamines and Sulfuric Acid.

    PubMed

    Elm, Jonas; Jen, Coty N; Kurtén, Theo; Vehkamäki, Hanna

    2016-05-26

    We investigate the molecular interaction between methyl-substituted N,N,N',N'-ethylenediamines, propane-1,3-diamine, butane-1,4-diamine, and sulfuric acid using computational methods. Molecular structure of the diamines and their dimer clusters with sulfuric acid is studied using three density functional theory methods (PW91, M06-2X, and ωB97X-D) with the 6-31++G(d,p) basis set. A high level explicitly correlated CCSD(T)-F12a/VDZ-F12 method is used to obtain accurate binding energies. The reaction Gibbs free energies are evaluated and compared with values for reactions involving ammonia and atmospherically relevant monoamines (methylamine, dimethylamine, and trimethylamine). We find that the complex formation between sulfuric acid and the studied diamines provides similar or more favorable reaction free energies than dimethylamine. Diamines that contain one or more secondary amino groups are found to stabilize sulfuric acid complexes more efficiently. Elongating the carbon backbone from ethylenediamine to propane-1,3-diamine or butane-1,4-diamine further stabilizes the complex formation with sulfuric acid by up to 4.3 kcal/mol. Dimethyl-substituted butane-1,4-diamine yields a staggering formation free energy of -19.1 kcal/mol for the clustering with sulfuric acid, indicating that such diamines could potentially be a key species in the initial step in the formation of new particles. For studying larger clusters consisting of a diamine molecule with up to four sulfuric acid molecules, we benchmark and utilize a domain local pair natural orbital coupled cluster (DLPNO-CCSD(T)) method. We find that a single diamine is capable of efficiently stabilizing sulfuric acid clusters with up to four acid molecules, whereas monoamines such as dimethylamine are capable of stabilizing at most 2-3 sulfuric acid molecules.

  7. Model estimates of inelastic calcium-hydrogen collision data for non-LTE stellar atmospheres modeling

    NASA Astrophysics Data System (ADS)

    Belyaev, A. K.; Yakovleva, S. A.; Guitou, M.; Mitrushchenkov, A. O.; Spielfiedel, A.; Feautrier, N.

    2016-03-01

    Aims: Inelastic processes in low-energy Ca + H and Ca+ + H- collisions are treated for the states from the ground state up to the ionic state with the aim to provide rate coefficients needed for non-LTE modeling of Ca in cool stellar atmospheres. Methods: The electronic molecular structure was determined using a recently proposed model approach that is based on an asymptotic method. Nonadiabatic nuclear dynamics were treated by means of multichannel formulas, based on the Landau-Zener model for nonadiabatic transition probabilities. Results: The cross sections and rate coefficients for inelastic processes in Ca + H and Ca+ + H- collisions were calculated for all transitions between 17 low-lying covalent states plus the ionic state. It is shown that the highest rate coefficient values correspond to the excitation, de-excitation, ion-pair formation, and mutual neutralization processes involving the Ca(4s5s 1,3S) and the ionic Ca+ + H- states. The next group with the second highest rate coefficients includes the processes involving the Ca(4s5p 1,3P), Ca(4s4d 1,3D), and Ca(4s4p 1P) states. The processes from these two groups are likely to be important for non-LTE modeling. Tables 2-11 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/587/A114

  8. Method for the determination of lignin content of a sample by flash pyrolysis in an atmosphere of hydrogen or helium and method therefor

    NASA Technical Reports Server (NTRS)

    Shakkottai, Parthasarathy (Inventor); Kwack, Eug Y. (Inventor); Lawson, Daniel D. (Inventor)

    1991-01-01

    The lignin content of wood, paper pulp or other material containing lignin (such as filter paper soaked in black liquor) is more readily determined by flash pyrolysis of the sample at approximately 550.degree. C. in a reducing atmosphere of hydrogen or in an inert atmosphere of helium followed by a rapid analysis of the product gas by a mass spectrometer. The heated pyrolysis unit as fabricated comprises a small platinum cup welded to an electrically-heated stainless steel ribbon with control means for programmed short duration (1.5 sec, approximately) heating and means for continuous flow of hydrogen or helium. The pyrolysis products enter an electron-ionization mode mass spectrometer for spectral evaluation. Lignin content is obtained from certain ratios of integrated ion currents of many mass spectral lines, the ratios being linearly related to the Kappa number of Klason lignin.

  9. Features of the propagation of laminar spherical flames initiated by a spark discharge in mixtures of methane, pentane, and hydrogen with air at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Rubtsov, N. M.; Seplyarskii, B. S.; Troshin, K. Ya.; Chernysh, V. I.; Tsvetkov, G. I.

    2011-10-01

    Using high-speed digital color cinematography, we studied the propagation of a laminar spherical flame in stoichiometric mixtures of hydrogen, methane, and pentane with air in the presence of additives at atmospheric pressure in constant-volume reactors, and derived quantitative data on the time of formation of a stable flame front. Cellular flames caused by gas-dynamic instability attributable to convective flows arising during the afterburning of gas were observed in hydrocarbon-air stoichiometric mixtures diluted with inert additives. It was found that the effect of additives of carbon dioxide and argon (>10%) and minor additives of CCl4 on the combustion of hydrocarbons, and of propylene on the combustion of hydrogen-rich mixtures, lead to periods of delay in the development of a laminar spherical flame; in addition, additives of propylene promote the combustion of hydrogen poor mixtures.

  10. High-efficiency tooth bleaching using non-thermal atmospheric pressure plasma with low concentration of hydrogen peroxide

    PubMed Central

    NAM, Seoul Hee; LEE, Hyun Woo; CHO, Soo Hyun; LEE, Jae Koo; JEON, Young Chan; KIM, Gyoo Cheon

    2013-01-01

    Light-activated tooth bleaching with a high hydrogen peroxide (HP; H2O2) concentration has risks and the actual role of the light source is doubtful. The use of conventional light might result in an increase in the temperature and cause thermal damage to the health of the tooth tissue. Objective: This study investigated the efficacy of tooth bleaching using non-thermal atmospheric pressure plasma (NAPP) with 15% carbamide peroxide (CP; CH6N2O3) including 5.4% HP, as compared with conventional light sources. Material and Methods: Forty human teeth were randomly divided into four groups: Group I (CP+NAPP), Group II (CP+plasma arc lamp; PAC), Group III (CP+diode laser), and Group IV (CP alone). Color changes (ΔE ) of the tooth and tooth surface temperatures were measured. Data were evaluated by one-way analysis of variance (ANOVA) and post-hoc Tukey's tests. Results: Group I showed the highest bleaching efficacy, with a ΔE value of 1.92-, 2.61 and 2.97-fold greater than those of Groups II, III and IV, respectively (P<0.05). The tooth surface temperature was maintained around 37ºC in Group I, but it reached 43ºC in Groups II and III. Conclusions: The NAPP has a greater capability for effective tooth bleaching than conventional light sources with a low concentration of HP without causing thermal damage. Tooth bleaching using NAPP can become a major technique for in-office bleaching in the near future. PMID:23857658

  11. Atmospheric Pressure Plasma CVD of Amorphous Hydrogenated Silicon Carbonitride (a-SiCN:H) Films Using Triethylsilane and Nitrogen

    SciTech Connect

    Srinivasan Guruvenket; Steven Andrie; Mark Simon; Kyle W. Johnson; Robert A. Sailer

    2011-10-04

    Amorphous hydrogenated silicon carbonitride (a-SiCN:H) thin films are synthesized by atmospheric pressure plasma enhanced chemical vapor (AP-PECVD) deposition using the Surfx Atomflow{trademark} 250D APPJ source with triethylsilane (HSiEt{sub 3}, TES) and nitrogen as the precursor and the reactive gases, respectively. The effect of the substrate temperature (T{sub s}) on the growth characteristics and the properties of a-SiCN:H films was evaluated. The properties of the films were investigated via scanning electron microscopy (SEM), atomic force microscopy (AFM) for surface morphological analyses, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) for chemical and compositional analyses; spectroscopic ellipsometry for optical properties and thickness determination and nanoindentation to determine the mechanical properties of the a-SiCN:H films. Films deposited at low T{sub s} depict organic like features, while the films deposited at high T{sub s} depict ceramic like features. FTIR and XPS studies reveal that an increases in T{sub s} helps in the elimination of organic moieties and incorporation of nitrogen in the film. Films deposited at T{sub s} of 425 C have an index of refraction (n) of 1.84 and hardness (H) of 14.8 GPa. A decrease in the deposition rate between T{sub s} of 25 and 250 C and increase in deposition rate between T{sub s} of 250 and 425 C indicate that the growth of a-SiCN:H films at lower T{sub s} are surface reaction controlled, while at high temperatures film growth is mass-transport controlled. Based on the experimental results, a potential route for film growth is proposed.

  12. On the hydrogen escape from Mars: Comments to "Variability of the hydrogen in the martian upper atmosphere as simulated by a 3D atmosphere-exosphere coupling" by J.Y. Chaufray et al. (2015, Icarus 245, 282-294)

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, Vladimir A.

    2017-01-01

    Nonthermal processes dominate in the escape of molecular hydrogen from Mars, and their exclusion in Chaufray et al. (2015) adversely affects the model results. High variations of escape of atomic hydrogen with solar activity in their model disagree with the low variations in the model by Krasnopolsky (JGR 107, E12, 5128, 2002).

  13. Proprietes des melanges de poudres d'aciers inoxydables 316L/h-BN et 409L/h-BN frittes sous differentes atmospheres (hydrogen-nitrogen)

    NASA Astrophysics Data System (ADS)

    Mercier, Thierry

    L'influence de la composition d'atmospheres de frittage "hydrogene---azote" sur les proprietes de specimens produits par metallurgie des poudres a partir de melanges de poudres d'aciers inoxydables 316L et 409L et de poudre de nitrure de bore hexagonal (h-BN) a ete etudiee. Ces proprietes ont ete comparees a celles de specimens sans h-BN frittes simultanement dans la meme atmosphere. Une mince couche dense s'est formee a la surface des echantillons contenant du h-BN frittes dans une atmosphere contenant au moins 50% en volume d'hydrogene. Cette couche dense ameliore generalement les proprietes de l'alliage 316L. Les proprietes de l'alliage 409L montrent une amelioration beaucoup moins significative qui s'amenuise lorsque l'atmosphere s'appauvrit en azote. L'azote favorise la corrosion de specimens de 409L avec ou sans h-BN. Quant au 316L, il demeure resistant a la corrosion malgre la presence d'un peu d'azote au frittage et l'addition de h-BN lui est benefique particulierement lorsque fritte en presence d'une teneur elevee d'azote (jusqu'a 50%vol. N2) qui permet tout de meme la formation d'une couche dense en surface.

  14. Safe venting of hydrogen

    SciTech Connect

    Stewart, W.F.; Dewart, J.M.; Edeskuty, F.J.

    1990-01-01

    The disposal of hydrogen is often required in the operation of an experimental facility that contains hydrogen. Whether the vented hydrogen can be discharged to the atmosphere safely depends upon a number of factors such as the flow rate and atmospheric conditions. Calculations have been made that predict the distance a combustible mixture can extend from the point of release under some specified atmospheric conditions. Also the quantity of hydrogen in the combustible cloud is estimated. These results can be helpful in deciding of the hydrogen can be released directly to the atmosphere, or if it must be intentionally ignited. 15 refs., 5 figs., 2 tabs.

  15. Modeling the temporal and spatial variations of the vertical structure of Jupiter's atmosphere using observations of the 3-0 hydrogen quadrupole lines

    NASA Technical Reports Server (NTRS)

    Cunningham, C. C.; Hunten, D. M.; Tomasko, M. G.

    1986-01-01

    An observational program was established in 1983 to monitor the spatial and temporal variations in the Jovian atmosphere over short and long time scales. The program involves tracking several different longitudes as they rotate around the planet from one limb to another. This tracking experiment was done at many different wavelengths including the 3-0 S(1) and S(0) hydrogen quadrupole lines as well as several broad band methane absorptions. The June 1983 hydrogen quadrupole data was reduced and equivalent widths were measured for approximately 25 east-west positions across the planet at 7 different latitudes for both wavelengths. The data for the South Tropical Zone (20 deg. S) was modeled extensively and the effects of the various model parameters on the value of the calculated equivalent widths of both lines was measured as a longitude rotated from the east (or morning) limb to the west (or evening) limb. The value of the equivalent width is also quite sensitive to the height of the NH3 cloud top and to the value used for the single scattering albedo. A combination of these parameters changing on a diurnal time scale could also explain these observations. This gradual increase from one limb to the other appears in the data for both the North and South Equatorial Belts as well as the equatorial region and the North Tropical Zone. Models that used only normal hydrogen and models that used only equilibrium hydrogen were studied.

  16. Atmospheric-Biospheric Interactions of Ambient Hydrogen Peroxide: Climatology at MT. Mitchell, N.C., and Transport Into Needles of Red Spruce

    NASA Astrophysics Data System (ADS)

    Claiborn, Candis Sue

    Hydrogen peroxide is an important atmospheric photo-oxidant whose ambient concentrations are enhanced by solar radiation, humidity, and low levels of nitrogen oxides, conditions which are observed in the mountainous regions of the southeastern United States. In this work we investigated the role of exposure to atmospheric hydrogen peroxide in the decline of the red spruce forests at Mt. Mitchell. The climatology of atmospheric hydrogen peroxide at this site was investigated in field studies conducted during the growing seasons (May through September) of 1987 and 1988. A second generation exposure chamber was designed and constructed for studying the interactions between reactive gases and plant species. The uptake of gas-phase hydrogen peroxide by whole spruce saplings was measured in this continuously -stirred tank reactor (CSTR)-type chamber. The results of these experiments were interpreted using a mathematical model of the spruce needle and the spruce stomatal zone which was based on the fundamental equations for multicomponent gas diffusion. Gas-phase hydrogen peroxide concentrations at Mt. Mitchell averaged 0.8 and 0.2 ppb in the summer and fall, respectively, and were found to range from the detection limit (~0.1 ppb) to over 4 ppb, making these values comparable to those reported in the literature for similar, remote sites. Cloud water concentrations were found to be comparable to, or higher than, concentrations reported in the literature, and ranged from 0.2 to 219 muM/L (mean 38 muM/L) and from 1.9 to 55 muM/L (mean 17 muM/L) during the summer and fall, respectively. When exposed during uptake experiments to gaseous hydrogen peroxide concentrations in the range of those observed at Mt. Mitchell, the calculated deposition velocity in the chamber was 0.1 and 0.09 cm s^ {-1} for daytime and nighttime exposures, respectively. We hypothesize, from the results of these experiments, that hydrogen peroxide uptake by spruce was not affected by stomatal opening

  17. Analyses of hydrogen in quartz and in sapphire using depth profiling by ERDA at atmospheric pressure: Comparison with resonant NRA and SIMS

    NASA Astrophysics Data System (ADS)

    Reiche, Ina; Castaing, Jacques; Calligaro, Thomas; Salomon, Joseph; Aucouturier, Marc; Reinholz, Uwe; Weise, Hans-Peter

    2006-08-01

    Hydrogen is present in anhydrous materials as a result of their synthesis and of their environment during conservation. IBA provides techniques to measure H concentration depth profiles allowing to identify various aspects of the materials including the history of objects such as gemstones used in cultural heritage. A newly established ERDA set-up, using an external microbeam of alpha particles, has been developed to study hydrated near-surface layers in quartz and sapphire by non-destructive H depth profiling in different atmospheres. The samples were also analysed using resonant NRA and SIMS.

  18. Two Regimes of Interaction of a Hot Jupiter’s Escaping Atmosphere with the Stellar Wind and Generation of Energized Atomic Hydrogen Corona

    NASA Astrophysics Data System (ADS)

    Shaikhislamov, I. F.; Khodachenko, M. L.; Lammer, H.; Kislyakova, K. G.; Fossati, L.; Johnstone, C. P.; Prokopov, P. A.; Berezutsky, A. G.; Zakharov, Yu. P.; Posukh, V. G.

    2016-12-01

    The interaction of escaping the upper atmosphere of a hydrogen-rich non-magnetized analog of HD 209458b with a stellar wind (SW) of its host G-type star at different orbital distances is simulated with a 2D axisymmetric multi-fluid hydrodynamic (HD) model. A realistic Sun-like spectrum of X-ray and ultraviolet radiation, which ionizes and heats the planetary atmosphere, together with hydrogen photochemistry, as well as stellar-planetary tidal interaction are taken into account to generate self-consistently an atmospheric HD outflow. Two different regimes of the planetary and SW interaction have been modeled. These are: (1) the “captured by the star” regime, when the tidal force and pressure gradient drive the planetary material beyond the Roche lobe toward the star, and (2) the “blown by the wind” regime, when sufficiently strong SW confines the escaping planetary atmosphere and channels it into the tail. The model simulates in detail the HD interaction between the planetary atoms, protons and the SW, as well as the production of energetic neutral atoms (ENAs) around the planet due to charge exchange between planetary atoms and stellar protons. The revealed location and shape of the ENA cloud, either as a paraboloid shell between the ionopause and bowshock (for the “blown by the wind” regime), or a turbulent layer at the contact boundary between the planetary stream and SW (for the “captured by the star” regime) are of importance for the interpretation of Lyα absorption features in exoplanetary transit spectra and characterization of the plasma environments.

  19. Etching of graphene in a Hydrogen-rich Atmosphere towards the Formation of Hydrocarbons in Circumstellar Clouds

    PubMed Central

    Martínez, José I.; Martín-Gago, José A.; Cernicharo, José; de Andres, Pedro L.

    2015-01-01

    We describe a mechanism that explains the formation of hydrocarbons and hydrocarbyls from hydrogenated graphene/graphite; hard C–C bonds are weakened and broken by the synergistic effect of chemisorbed hydrogen and high temperature vibrations. Total energies, optimized structures, and transition states are obtained from Density Functional Theory simulations. These values have been used to determine the Boltzman probability for a thermal fluctuation to overcome the kinetic barriers, yielding the time scale for an event to occur. This mechanism can be used to rationalize the possible routes for the creation of small hydrocarbons and hydrocarbyls from etched graphene/graphite in stellar regions. PMID:26709358

  20. Variations in stable hydrogen and oxygen isotopes in atmospheric water vapor in the marine boundary layer across a wide latitude range.

    PubMed

    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.

  1. Condensation-inhibited convection in hydrogen-rich atmospheres . Stability against double-diffusive processes and thermal profiles for Jupiter, Saturn, Uranus, and Neptune

    NASA Astrophysics Data System (ADS)

    Leconte, Jérémy; Selsis, Franck; Hersant, Franck; Guillot, Tristan

    2017-02-01

    In an atmosphere, a cloud condensation region is characterized by a strong vertical gradient in the abundance of the related condensing species. On Earth, the ensuing gradient of mean molecular weight has relatively few dynamical consequences because N2 is heavier than water vapor, so that only the release of latent heat significantly impacts convection. On the contrary, in a hydrogen dominated atmosphere (e.g., giant planets), all condensing species are significantly heavier than the background gas. This can stabilize the atmosphere against convection near a cloud deck if the enrichment in the given species exceeds a critical threshold. This raises two questions. What is transporting energy in such a stabilized layer, and how affected can the thermal profile of giant planets be? To answer these questions, we first carry out a linear analysis of the convective and double-diffusive instabilities in a condensable medium showing that an efficient condensation can suppress double-diffusive convection. This suggests that a stable radiative layer can form near a cloud condensation level, leading to an increase in the temperature of the deep adiabat. Then, we investigate the impact of the condensation of the most abundant species (water) with a steady-state atmosphere model. Compared to standard models, the temperature increase can reach several hundred degrees at the quenching depth of key chemical tracers. Overall, this effect could have many implications for our understanding of the dynamical and chemical state of the atmosphere of giant planets, for their future observations (with Juno for example), and for their internal evolution.

  2. The Jovian Atmospheres

    NASA Technical Reports Server (NTRS)

    Allison, Michael (Editor); Travis, Larry D. (Editor)

    1986-01-01

    A conference on the atmosphere of Jupiter produced papers in the areas of thermal and ortho-para hydrogen structure, clouds and chemistry, atmospheric structure, global dynamics, synoptic features and processes, atmospheric dynamics, and future spaceflight opportunities. A session on the atmospheres of Uranus and Neptune was included, and the atmosphere of Saturn was discussed in several papers.

  3. Reliable determination of oxygen and hydrogen isotope ratios in atmospheric water vapour adsorbed on 3A molecular sieve.

    PubMed

    Han, Liang-Feng; Gröning, Manfred; Aggarwal, Pradeep; Helliker, Brent R

    2006-01-01

    The isotope ratio of atmospheric water vapour is determined by wide-ranging feedback effects from the isotope ratio of water in biological water pools, soil surface horizons, open water bodies and precipitation. Accurate determination of atmospheric water vapour isotope ratios is important for a broad range of research areas from leaf-scale to global-scale isotope studies. In spite of the importance of stable isotopic measurements of atmospheric water vapour, there is a paucity of published data available, largely because of the requirement for liquid nitrogen or dry ice for quantitative trapping of water vapour. We report results from a non-cryogenic method for quantitatively trapping atmospheric water vapour using 3A molecular sieve, although water is removed from the column using standard cryogenic methods. The molecular sieve column was conditioned with water of a known isotope ratio to 'set' the background signature of the molecular sieve. Two separate prototypes were developed, one for large collection volumes (3 mL) and one for small collection volumes (90 microL). Atmospheric water vapour was adsorbed to the column by pulling air through the column for several days to reach the desired final volume. Water was recovered from the column by baking at 250 degrees C in a dry helium or nitrogen air stream and cryogenically trapped. For the large-volume apparatus, the recovered water differed from water that was simultaneously trapped by liquid nitrogen (the experimental control) by 2.6 per thousand with a standard deviation (SD) of 1.5 per thousand for delta(2)H and by 0.3 per thousand with a SD of 0.2 per thousand for delta(18)O. Water-vapour recovery was not satisfactory for the small volume apparatus.

  4. Hydrogen Isotopic Composition of Arctic and Atmospheric CH4 Determined by a Portable Near-Infrared Cavity Ring-Down Spectrometer with a Cryogenic Pre-Concentrator.

    PubMed

    Chen, Y; Lehmann, Kevin K; Peng, Y; Pratt, L M; White, J R; Cadieux, S B; Sherwood Lollar, B; Lacrampe-Couloume, G; Onstott, T C

    2016-10-01

    In this study, near-infrared continuous wave cavity ring-down spectroscopy was applied to the measurement of the δ(2)H of methane (CH4). The cavity ring-down spectrometer (CRDS) system consisted of multiple DFB laser diodes to optimize selection of spectral line pairs. By rapidly switching measurements between spectral line peaks and the baseline regions, the long-term instrumental drift was minimized, substantially increasing measurement precision. The CRDS system coupled with a cryogenic pre-concentrator measured the δ(2)H of terrestrial atmospheric CH4 from 3 standard liters of air with a precision of ±1.7‰. The rapidity with which both C and H isotopic measurements of CH4 can be made with the CRDS will enable hourly monitoring of diurnal variations in terrestrial atmospheric CH4 signatures that can be used to increase the resolution of global climate models for the CH4 cycle. Although the current instrument is not capable of measuring the δ(2)H of 10 ppbv of martian CH4, current technology does exist that could make this feasible for future spaceflight missions. As biological and abiotic CH4 sources have overlapping carbon isotope signatures, dual-element (C and H) analysis is key to reliable differentiation of these sources. Such an instrument package would therefore offer improved ability to determine whether or not the CH4 recently detected in the martian atmosphere is biogenic in origin. Key Words: Arctic-Hydrogen isotopes-Atmospheric CH4-CRDS-Laser. Astrobiology 16, 787-797.

  5. Modeling of pressure-induced far-infrared absorption spectra Molecular hydrogen pairs. [in outer planets atmospheres

    NASA Technical Reports Server (NTRS)

    Borysow, J.; Trafton, L.; Frommhold, L.; Birnbaum, G.

    1985-01-01

    Meyer et al. (1985) have calculated the accurate induced dipole moment function of H2-H2 from first principles, using highly correlated wave functions for the first time in such work. The present paper is concerned with the collision-induced translational-rotational absorption coefficient for molecular hydrogen pairs, taking into account computations on the basis of the fundamental theory considered by Meyer et al. Data have been obtained for temperatures in the range from 40 to 300 K. Criteria are developed for choosing among various model line shapes. It is found that certain models are capable of approximating the quantum profiles closely, with rms errors of only a few percent.

  6. The reaction of atomic hydrogen with germane - Temperature dependence of the rate constant and implications for germane photochemistry in the atmospheres of Jupiter and Saturn

    NASA Technical Reports Server (NTRS)

    Nava, David F.; Payne, Walter A.; Marston, George; Stief, Louis J.

    1993-01-01

    Studies of the formation and loss processes for GeH4 are required in order to provide data to help determine the major chemical form in which germanium exists in the atmospheres of Jupiter and Saturn. The reaction of hydrogen atoms with germane is one of the most important of these reactions. The absolute rate constant for this reaction as a function of temperature and pressure is studied. Flash photolysis of dilute mixtures of GeH4 in argon, combined with time-resolved detection of H atoms via Lyman alpha resonance fluorescence, is employed to measure the reaction rate. The reaction is shown to be moderately rapid, independent of total pressure, but possessing a positive temperature dependence.

  7. Growth process of hydrogenated amorphous carbon films synthesized by atmospheric pressure plasma enhanced CVD using nitrogen and helium as a dilution gas

    NASA Astrophysics Data System (ADS)

    Mori, Takanori; Sakurai, Takachika; Sato, Taiki; Shirakura, Akira; Suzuki, Tetsuya

    2016-04-01

    Hydrogenated amorphous carbon films with various thicknesses were synthesized by dielectric barrier discharge-based plasma deposition under atmospheric pressure diluted with nitrogen (N2) and helium (He) at various pulse frequencies. The C2H2/N2 film showed cauliflower-like-particles that grew bigger with the increase in film’s thickness. At 5 kHz, the film with a thickness of 2.7 µm and smooth surface was synthesized. On the other hand, the films synthesized from C2H2/He had a smooth surface and was densely packed with domed particles. The domed particles extended with the increase in the film thickness, enabling it to grow successfully to 37 µm with a smooth surface.

  8. Stable hydrogen isotopic composition of n-alkanes in atmospheric aerosols as a tracer for the source region of terrestrial plant waxes

    NASA Astrophysics Data System (ADS)

    Yamamoto, S.; Kawamura, K.

    2009-12-01

    Studies on molecular composition and compound-specific carbon isotopic ratio (δ13C) of leaf wax n-alkanes in atmospheric aerosols have revealed a long-range atmospheric transport of terrestrial higher plant materials over the south Atlantic and western Pacific oceans. However, molecular and δ13C compositions of terrestrial plant waxes in the eastern part of the Asian continent are relatively constant reflecting C3-dominated vegetation, which makes it difficult to specify the source regions of plant materials in the atmospheric aerosols over the East Asia and northwest Pacific regions. Recent observation displays a large (>100‰) spatial variation in hydrogen isotopic composition (δD) of rainwater in East Asia. Because δD values of terrestrial higher plants sensitively reflect those of precipitation waters, δD of leaf waxes are expected to provide information on their source region. In this study, we measured the δD of n-alkanes in atmospheric aerosols from Tokyo to better understand the origin of leaf wax n-alkanes in atmospheric aerosols. The δD values of fossil fuel n-alkanes (C21 to C24) in Tokyo aerosols range from -65 to -94‰, which are in a range of those reported in marine crude oils. In contrast, the δD of higher molecular weight (C29 and C31) n-alkanes (δDHMW) show much larger values by ~70‰ than those of fossil fuel n-alkanes. Their values were found to exhibit concomitant variations with carbon preference index (CPI), suggesting that the δDHMW reflect the δD of leaf wax n-alkanes with a variable contribution from fossil fuel n-alkanes. Nevertheless, good positive correlation (r = 0.89, p < 0.01) between the δDHMW and CPI values enable us to remove the contribution of fossil fuels using a mass balance approach by assuming that CPI of fossil fuel is 1 and CPI of plant waxes is 5-15. Calculated n-alkane δD values averaged from -170 to -185‰ for C29 and from -155 to -168‰ for C31. These values are consistent with those reported from

  9. Prebiotic synthesis in atmospheres containing CH4, CO, and CO2. II. Hydrogen cyanide, formaldehyde and ammonia.

    PubMed

    Schlesinger, G; Miller, S L

    1983-01-01

    The electric discharge synthesis of HCN, H2CO, NH3 and urea has been investigated using various mixtures of CH4, CO, CO2, N2, NH3, H2O, and H2. HCN and H2CO were each synthesized in yields as high as 10% from CH4 as a carbon source. Similar yields were obtained from CO when H2/CO greater than 1.0 and from CO2 when H2/CO2 greater than 2.0. At H2/CO2 less than 1.0 the yields fall off drastically. Good yields of NH3 (0.7 to 5%) and fair yields of urea (0.02 to 0.63%) based on nitrogen were also obtained. The directly synthesized NH3 together with the NH3 obtained from the hydrolysis of HCN, nitriles and urea could have been a major source of ammonia in the atmosphere and oceans of the primitive earth. These results show that prebiotic syntheses from HCN and H2CO to give products such as purines and sugars and some amino acids could have occurred in primitive atmospheres containing CO and CO2 provided the H2/CO and H2/CO2 ratios were greater than about 1.0. Methane containing atmospheres give comparable quantities of HCN and H2CO, and are superior in the synthesis of amino acids.

  10. Interaction of hydrogen chloride with alumina. [atmospheric effluent concentrations and interaction of solid rocket propellants used in space shuttle

    NASA Technical Reports Server (NTRS)

    Bailey, R. R.; Wightman, J. P.

    1978-01-01

    The influence of temperature, pressure, and outgas conditions on the absorption of hydrogen chloride and water vapor on both alpha and gamma alumina was studied. Characterization of the adsorbents was performed using X-ray powder diffraction, scanning electron microscopy (SEM), low temperature nitrogen adsorption desorption measurements, BET nitrogen surface area measurements and electron spectroscopy for chemical analysis (ESCA). Water vapor adsorption isotherms at 30, 40, and 50 C were measured on alpha and gamma alumina after outgassing at 80, 200, and 400 C. Both outgas temperature and adsorption temperature influenced the adsorption of water vapor on the aluminas. The water vapor adsorption was completely reversible. Alpha alumina absorbed more water per unit area than gamma alumina. Differences in the adsorption capacity for water vapor of the two aluminas were explained on the basis of ideal surface models of alpha and gamma alumina. Isosteric heats of adsorption for water vapor on the aluminas were determined over a limited range of surface coverage.

  11. Optimization and application of atmospheric pressure chemical and photoionization hydrogen-deuterium exchange mass spectrometry for speciation of oxygen-containing compounds.

    PubMed

    Acter, Thamina; Kim, Donghwi; Ahmed, Arif; Jin, Jang Mi; Yim, Un Hyuk; Shim, Won Joon; Kim, Young Hwan; Kim, Sunghwan

    2016-05-01

    This paper presents a detailed investigation of the feasibility of optimized positive and negative atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) and atmospheric pressure photoionization (APPI) MS coupled to hydrogen-deuterium exchange (HDX) for structural assignment of diverse oxygen-containing compounds. The important parameters for optimization of HDX MS were characterized. The optimized techniques employed in the positive and negative modes showed satisfactory HDX product ions for the model compounds when dichloromethane and toluene were employed as a co-solvent in APCI- and APPI-HDX, respectively. The evaluation of the mass spectra obtained from 38 oxygen-containing compounds demonstrated that the extent of the HDX of the ions was structure-dependent. The combination of information provided by different ionization techniques could be used for better speciation of oxygen-containing compounds. For example, (+) APPI-HDX is sensitive to compounds with alcohol, ketone, or aldehyde substituents, while (-) APPI-HDX is sensitive to compounds with carboxylic functional groups. In addition, the compounds with alcohol can be distinguished from other compounds by the presence of exchanged peaks. The combined information was applied to study chemical compositions of degraded oils. The HDX pattern, double bond equivalent (DBE) distribution, and previously reported oxidation products were combined to predict structures of the compounds produced from oxidation of oil. Overall, this study shows that APCI- and APPI-HDX MS are useful experimental techniques that can be applied for the structural analysis of oxygen-containing compounds.

  12. Accelerated formation of sodium depletion layer on soda lime glass surface by corona discharge treatment in hydrogen atmosphere

    NASA Astrophysics Data System (ADS)

    Kawaguchi, Keiga; Ikeda, Hiroshi; Sakai, Daisuke; Funatsu, Shiro; Uraji, Keiichiro; Yamamoto, Kiyoshi; Suzuki, Toshio; Harada, Kenji; Nishii, Junji

    2014-05-01

    Formation of a sodium depletion layer on a soda lime glass surface was accelerated efficiently using a corona discharge treatment in H2 atmosphere. One origin of such acceleration was the preferential generation of H+ with a larger mobility at an anode needle end with a lower applied voltage than that in air. The second origin was the applied voltage across the glass plate during the corona discharge treatment, which was estimated theoretically as 2.7 times higher than that in air. These two effects doubled the depletion layer thickness compared with that in air.

  13. The continuous measurement of hydrogen chloride in the ambient atmosphere using the dual isotope infrared absorption technique

    NASA Technical Reports Server (NTRS)

    Williams, K. G.

    1974-01-01

    The results of a program to develop a prototype gas filter correlation NDIR analyzer capable of providing the required HCl measurement capability, while maintaining an adequate rejection of any other gases anticipated in the atmosphere are presented. Examples of the performance of the prototype analyzer are presented which show an rms noise equivalent concentration of 0.06 ppm of HCl was achieved while maintaining an electronically determined 10% to 90% time response to gas samples of about 2 seconds. No measureable response was observed to CO2, CO, and H2O while maintaining an adequate rejection of the hydrocarbons, for example CH4 and n-hexane. The experiments were performed which demonstrate that the span stability of the HCl gas filter correlation analyzer is unaffected by the presence of water vapor and which support the belief that the incorporation of a relatively open-volume, multiple path sample cell into the instrument would enable ground station as well as airborne measurements of trace quantities of HCl in the ambient atmosphere to be performed.

  14. Ground-based Infrared Observations of Water Vapor and Hydrogen Peroxide in the Atmosphere of Mars Near Summer Solstice

    NASA Astrophysics Data System (ADS)

    Encrenaz, Therese; Greathouse, T. K.; Bitner, M.; Kruger, A.; Lacy, J. H.; Richter, M. J.; Bezard, B.; Fouchet, T.; Lefevre, F.; Forget, F.; Atreya, S. K.

    2008-09-01

    Observations of HDO and H2O2 martian lines have been made with the TEXES instrument (Texas Echelon Cross Echelle Spectrograph) at the NASA Infrared Telescope Facility near summer solstice on two separate occasions, in Feb. 2001 (Ls = 110 deg.) and June 2008 (Ls = 80 deg.). Maps of HDO have been obtained by ratioing the depth of a weak HDO transition to the depth of a nearby CO2 line of comparable intensity. Both maps clearly show the maximum water vapor content in the vicinity of the north pole. The H2O2 molecule was not detected during the Feb. 2001 run (Encrenaz et al. AA 396, 1037-1044, 2002), but was marginally detectable during the June 2008 run. In both cases, the inferred H2O2 abundance is lower than the predictions of the GCM. This conclusion agrees with other observations performed near equinox (Ls = 332 deg., Encrenaz et al. Icarus 195, 547, 2008) while, in contrast, the observations for Ls = 206 deg. (beginning of southern spring) were in good agreement with the models (Encrenaz et al. Icarus 170, 424, 2004). The seasonal behaviour of hydrogen peroxide on Mars is not well understood and requires further investigation.

  15. Climatic effects of atmospheric transport and transformation of hydrogenous species. Progress report, July 1, 1980-June 30, 1981

    SciTech Connect

    Oestlund, H.G.; Mason, A.S.

    1981-01-01

    The atmospheric sampling for tritium as HTO and HT has been continued at the stations at Baring Head Lighthouse, New Zealand, and in Fairbanks, Alaska, and Miami, Florida. In addition, tritium bound to hydrocarbons has also been sampled in Miami. All HT sources are in the Northern Hemisphere; when the global burden of tritium in the form of HTO and HT, was estimated, it was found that the variations between Fairbanks, Alaska, and Miami, Florida, were quite erratic and warranted at least one more northern station. A station was therefore established at Oregon State University's Marine Sciences Center, at Newport, Oregon, on the Pacific Ocean. The station was established on January 15, 1981 and is now functioning without problems. Tabulated results from all four stations are presented. The global inventory of tritium gas was about 1.3 kg of tritium in the mid-70s. It has been steadily decreasing, and the present value, June 1981 is approximately 700 g. This development is attributed to virtual cessation of the reprocessing of nuclear fuel elements and possibly better precautions taken by various nuclear installations handling tritium in gaseous form. (JGB)

  16. Hydrogen cyanide production due to mid-size impacts in a redox-neutral N2-rich atmosphere.

    PubMed

    Kurosawa, Kosuke; Sugita, Seiji; Ishibashi, Ko; Hasegawa, Sunao; Sekine, Yasuhito; Ogawa, Nanako O; Kadono, Toshihiko; Ohno, Sohsuke; Ohkouchi, Naohiko; Nagaoka, Yoichi; Matsui, Takafumi

    2013-06-01

    Cyanide compounds are amongst the most important molecules of the origin of life. Here, we demonstrate the importance of mid-size (0.1-1 km in diameter) hence frequent meteoritic impacts to the cyanide inventory on the early Earth. Subsequent aerodynamic ablation and chemical reactions with the ambient atmosphere after oblique impacts were investigated by both impact and laser experiments. A polycarbonate projectile and graphite were used as laboratory analogs of meteoritic organic matter. Spectroscopic observations of impact-generated ablation vapors show that laser irradiation to graphite within an N2-rich gas can produce a thermodynamic environment similar to that produced by oblique impacts. Thus, laser ablation was used to investigate the final chemical products after this aerodynamic process. We found that a significant fraction (>0.1 mol%) of the vaporized carbon is converted to HCN and cyanide condensates, even when the ambient gas contains as much as a few hundred mbar of CO2. As such, the column density of cyanides after carbon-rich meteoritic impacts with diameters of 600 m would reach ~10 mol/m(2) over ~10(2) km(2) under early Earth conditions. Such a temporally and spatially concentrated supply of cyanides may have played an important role in the origin of life.

  17. Oxidation resistant organic hydrogen getters

    DOEpatents

    Shepodd, Timothy J.; Buffleben, George M.

    2008-09-09

    A composition for removing hydrogen from an atmosphere, comprising a mixture of a polyphenyl ether and a hydrogenation catalyst, preferably a precious metal catalyst, and most preferably Pt. This composition is stable in the presence of oxygen, will not polymerize or degrade upon exposure to temperatures in excess of 200.degree. C., or prolonged exposure to temperatures in the range of 100-300.degree. C. Moreover, these novel hydrogen getter materials can be used to efficiently removing hydrogen from mixtures of hydrogen/inert gas (e.g., He, Ar, N.sub.2), hydrogen/ammonia atmospheres, such as may be encountered in heat exchangers, and hydrogen/carbon dioxide atmospheres. Water vapor and common atmospheric gases have no adverse effect on the ability of these getter materials to absorb hydrogen.

  18. Kinetic measurements on the reactivity of hydrogen peroxide and ozone towards small atmospherically relevant aldehydes, ketones and organic acids in aqueous solution

    NASA Astrophysics Data System (ADS)

    Schöne, L.; Herrmann, H.

    2013-10-01

    Within the aqueous atmospheric environment free radical reactions are an important degradation process for organic compounds. Nevertheless, non-radical oxidants like hydrogen peroxide and ozone also contribute to the degradation and conversion of this substance group (Tilgner und Herrmann, 2010). In this work kinetic investigations of non-radical reactions were conducted using UV/Vis spectroscopy (dual-beam spectrophotometer and Stopped Flow technique) and a capillary electrophoresis system applying pseudo-first order kinetics of glyoxal, methylglyoxal, glycolaldehyde, glyoxylic, pyruvic and glycolic acids as well as methacrolein (MACR) and methyl vinyl ketone (MVK) towards H2O2 and ozone. The measurements indicate rather small rate constants at room temperature of k2nd < 3 M-1 s-1 (except for the unsaturated compounds exposed to ozone). Compared to radical reaction rate constants the values are about 10 orders of magnitude smaller (kOH· ~ 109 M-1 s-1). However, when considering the much larger non-radical oxidant concentrations compared to radical concentrations in urban cloud droplets, calculated turnovers change the picture to more important H2O2 reactions especially when compared to the nitrate radical. For some reactions also mechanistic suggestions are given.

  19. Kinetic measurements of the reactivity of hydrogen peroxide and ozone towards small atmospherically relevant aldehydes, ketones and organic acids in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Schöne, L.; Herrmann, H.

    2014-05-01

    Free radical reactions are an important degradation process for organic compounds within the aqueous atmospheric environment. Nevertheless, non-radical oxidants such as hydrogen peroxide and ozone also contribute to the degradation and conversion of these substances (Tilgner and Herrmann, 2010). In this work, kinetic investigations of non-radical reactions were conducted using UV / Vis spectroscopy (dual-beam spectrophotometer and stopped flow technique) and a capillary electrophoresis system applying pseudo-first order kinetics to reactions of glyoxal, methylglyoxal, glycolaldehyde, glyoxylic, pyruvic and glycolic acid as well as methacrolein (MACR) and methyl vinyl ketone (MVK) with H2O2 and ozone at 298 K. The measurements indicate rather small rate constants at room temperature of k2nd < 3 M-1 s-1 (except for the unsaturated compounds exposed to ozone). Compared to radical reaction rate constants the values are about 10 orders of magnitude smaller (kOH • ~109 M-1 s-1). However, when considering the much larger non-radical oxidant concentrations compared to radical concentrations in urban cloud droplets, calculated first-order conversion rate constants change the picture towards H2O2 reactions becoming more important, especially when compared to the nitrate radical. For some reactions mechanistic suggestions are also given.

  20. Structure-dependent degradation of polar compounds in weathered oils observed by atmospheric pressure photo-ionization hydrogen/deuterium exchange ultrahigh resolution mass spectrometry.

    PubMed

    Islam, Ananna; Kim, Donghwi; Yim, Un Hyuk; Shim, Won Joon; Kim, Sunghwan

    2015-10-15

    The resin fractions of fresh mixtures of three oils spilled during the M/V Hebei Spirit oil spill, as well as weathered oils collected at weathering stages II and IV from the oil spill site were analyzed and compared by atmospheric pressure photo-ionization hydrogen/deuterium exchange mass spectrometry (HDX MS). The significantly decreased abundance of N(+) and [N-H+D](+) ions suggested that secondary and tertiary amine-containing compounds were preferentially degraded during the early stage of weathering. [N+H](+) and [N+D](+) ions previously attributed to pyridine-type compounds degraded more slowly than secondary and tertiary amine-containing compounds. The preferential degradation of nitrogen-containing compounds was confirmed by photo-degradation experiments using 15 standard compounds. In addition, significant increases of [S1O1+H](+) and [S1O1+D](+) ions with higher DBE values were observed from fresh oil mixtures as compared to stages II and IV samples, and that could be linked with the decrease of higher DBE compounds of the S1 class. This study presented convincing arguments and evidence demonstrating that secondary and tertiary amines were more vulnerable to photo-degradation than compounds containing pyridine, and hence, preferential degradation depending on chemical structures must be considered in the production of hazardous or toxic components.

  1. The a 3Σg+ - b 3Σu+ Continuum Emission from Electron Impact of Molecular Hydrogen in Saturn's Atmosphere

    NASA Astrophysics Data System (ADS)

    Hein, J. D.; Johnson, P. V.; Liu, X.; Malone, C. P.; Khakoo, M. A.

    2014-12-01

    Shemansky et al. (2009, Planetary and Space Science 57: 1659-1670) have reported observations of hydrogen atoms flowing out of the top of Saturn's sunlit thermosphere in a confined, distinct plume of ballistic and escaping orbits, and a continuous distribution of H atoms from the top of Saturn's atmosphere to at least 45 Saturn radii (RS) in the satellite orbital plane and to 25 RS azimuthally above and below the plane. These observations have revealed the importance of the excitation of H2 by low energy electrons. H2 is efficiently excited to the triplet states by low energy electrons, and all triplet excitations result in the dissociation of H2 and the production of hot H atoms. Because of this, the electron impact excitation of H2 is an important energy deposition mechanism in the upper atmospheres of Saturn and other giant planets. The a 3Σg+ - b 3Σu continuum transition, which dominates all other H2 transitions in the 168-190 nm region, provides a unique spectral window through which the triplet transition can be observed with the Cassini spacecraft. The excitation and emission cross sections of the a 3Σg+ state and other triplet states are required for the extraction of the triplet emission and excitation rates from the apparent emission rate measured by the spacecraft. These emission and excitation rates, in turn, help to determine the energy deposition rate by electron impact excitation. Unfortunately, large discrepancies exist between published measurements of the a 3Σg+ - b 3Σu continuum transition. In order to begin to address this issue, we have recently revisited the problem by measuring electron impact induced a 3Σg+ - b 3Σu emission cross sections. We have also measured direct excitation cross sections of the triplet a 3Σg+ state. Using these, we are able to partition the excitation function into its direct and cascade components. As stated above, these results will enable improved understanding of phenomena observed in Saturn's atmosphere

  2. Hydrogen Sulfide Sequestration and Storage in Geothermal System: New Mitigation Strategy to Reduce H2S from the Atmosphere and Detect its Mineralization with Multiple Sulfur Isotopic Systematics

    NASA Astrophysics Data System (ADS)

    Marieni, C.; Stefansson, A.; Gudbrandsson, S.; Gunnarsson, I.; Aradottir, E. S.; Gunnarsson Robin, J.; Ono, S.

    2015-12-01

    Hydrogen sulfide (H2S) is one of the major components in geothermal fluids and is commonly emitted into the atmosphere from geothermal power plants causing potential environmental problems. Among several mitigation methods proposed to reduce the H2S emissions, is H2S sequestration into geothermal systems. Reykjavík Energy is undertaking a pilot project at Hellisheidi geothermal system (SW Iceland) called Sulfix project where H2S is being injected into the geothermal reservoir for permanent sequestration into pyrite. The SulFix project started its operation in June 2014: the soluble geothermal gases are dissolved in geothermal waste water, and injected at 8 bars into the high temperature reservoir (>200˚C) at 750 m below the wellhead. The reactions involving sulfur in the geothermal reservoir may be traced using sulfur fluid chemistry and multiple sulfur isotope systematics (32S, 33S, 34S and 36S), including mixing between the reservoir geothermal fluid and the injection fluid, sulfide mineralization and oxidation of sulfide to sulfate. In this study we investigated the multiple sulfur isotope systematics upon sulfide mineralization under geothermal conditions. High temperature flow through experiments were carried out in basaltic glass at 200-250°C and ~5 mmol/kg H2S to study the fluid-rock interaction. The results indicate that the sulfide mineralization occurs rapidly under geothermal conditions, highlighting the leaching rate of iron from the basaltic glass as the mineralization rate determining factor. Moreover, the formation of sulfide may be traced using the δ34S-Δ33S relationship in the fluids and pyrite formation - for example to determine if non-reactive mixing between the injection fluids and reservoir fluids occurs at Hellisheidi. The experimental results have been further supported by geochemical modeling involving multiple sulfur isotope fractionation between aqueous sulfide species and rocks upon basalt dissolution and secondary pyrite formation.

  3. Process for hydrogenating coal and coal solvents

    DOEpatents

    Tarrer, Arthur R.; Shridharani, Ketan G.

    1983-01-01

    A novel process is described for the hydrogenation of coal by the hydrogenation of a solvent for the coal in which the hydrogenation of the coal solvent is conducted in the presence of a solvent hydrogenation catalyst of increased activity, wherein the hydrogenation catalyst is produced by reacting ferric oxide with hydrogen sulfide at a temperature range of 260.degree. C. to 315.degree. C. in an inert atmosphere to produce an iron sulfide hydrogenation catalyst for the solvent. Optimally, the reaction temperature is 275.degree. C. Alternately, the reaction can be conducted in a hydrogen atmosphere at 350.degree. C.

  4. Hydrogen separation process

    DOEpatents

    Mundschau, Michael; Xie, Xiaobing; Evenson, IV, Carl; Grimmer, Paul; Wright, Harold

    2011-05-24

    A method for separating a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to a hydrogen separation membrane system comprising a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for separating a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to an integrated water gas shift/hydrogen separation membrane system wherein the hydrogen separation membrane system comprises a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for pretreating a membrane, comprising: heating the membrane to a desired operating temperature and desired feed pressure in a flow of inert gas for a sufficient time to cause the membrane to mechanically deform; decreasing the feed pressure to approximately ambient pressure; and optionally, flowing an oxidizing agent across the membrane before, during, or after deformation of the membrane. A method of supporting a hydrogen separation membrane system comprising selecting a hydrogen separation membrane system comprising one or more catalyst outer layers deposited on a hydrogen transport membrane layer and sealing the hydrogen separation membrane system to a porous support.

  5. Biological hydrogen photoproduction

    SciTech Connect

    Nemoto, Y.

    1995-09-01

    Following are the major accomplishments of the 6th year`s study of biological hydrogen photoproduction which were supported by DOE/NREL. (1) We have been characterizing a biological hydrogen production system using synchronously growing aerobically nitrogen-fixing unicellular cyanobacterium, Synechococcus sp. Miami BG 043511. So far it was necessary to irradiate the cells to produce hydrogen. Under darkness they did not produce hydrogen. However, we found that, if the cells are incubated with oxygen, they produce hydrogen under the dark. Under 80% argon + 20% oxygen condition, the hydrogen production activity under the dark was about one third of that under the light + argon condition. (2) Also it was necessary so far to incubate the cells under argon atmosphere to produce hydrogen in this system. Argon treatment is very expensive and should be avoided in an actual hydrogen production system. We found that, if the cells are incubated at a high cell density and in a container with minimum headspace, it is not necessary to use argon for the hydrogen production. (3) Calcium ion was found to play an important role in the mechanisms of protection of nitrogenase from external oxygen. This will be a clue to understand the reason why the hydrogen production is so resistant to oxygen in this strain. (4) In this strain, sulfide can be used as electron donor for the hydrogen production. This result shows that waste water can be used for the hydrogen production system using this strain.

  6. Atmospheric hydrogen peroxide and organic hydroperoxides during PRIDE-PRD'06, China: their concentration, formation mechanism and contribution to secondary aerosols

    NASA Astrophysics Data System (ADS)

    Hua, W.; Chen, Z. M.; Jie, C. Y.; Kondo, Y.; Hofzumahaus, A.; Takegawa, N.; Lu, K. D.; Miyazaki, Y.; Kita, K.; Wang, H. L.; Zhang, Y. H.; Hu, M.

    2008-06-01

    Atmospheric hydrogen peroxide (H2O2) and organic hydroperoxides were measured from 18 to 30 July in 2006 during the PRIDE-PRD'06 campaign at Backgarden, a rural site located 48 km north of Guangzhou, a mega-city in southern China. A ground-based instrument was used as a scrubbing coil collector to sample ambient air, followed by on-site analysis by high-performance liquid chromatography (HPLC) coupled with post-column derivatization and fluorescence detection. The H2O2 mixing ratio over the 13 days ranged from below the detection limit to a maximum of 4.6 ppbv, with a mean (and standard deviation) of (1.26±1.24) ppbv during the daytime (08:00-20:00 LT). Methyl hydroperoxide (MHP), with a maximum of 0.8 ppbv and a mean (and standard deviation) of (0.28±0.10) ppbv during the daytime, was the dominant organic hydroperoxide. Other organic peroxides, including bis-hydroxymethyl hydroperoxide (BHMP), peroxyacetic acid (PAA), hydroxymethyl hydroperoxide (HMHP), 1-hydroxy-ethyl hydroperoxide (1-HEHP) and ethyl hydroperoxide (EHP), were detected occasionally. The concentration of H2O2 exhibited a pronounced diurnal variation on sunny days, with a peak mixing ratio in the afternoon (12:00-18:00 LT), but lacked an explicit diurnal cycle on cloudy days. Sometimes a second peak mixing ratio of H2O2 was observed during the evening, suggesting that H2O2 was produced by the ozonolysis of alkenes. The diurnal variation profile of MHP was, in general, consistent with that of H2O2. The estimation indicated that in the morning the H2O2 detected was formed mostly through local photochemical activity, with the rest probably attributable to vertical transport. It is notable that relatively high levels of H2O2 and MHP were found in polluted air. The unexpectedly high level of HO2 radicals detected in this region can account for the production of hydroperoxides, while the high level of NOx suppressed the formation of hydroperoxides significantly. High concentrations of hydroperoxides

  7. Atmospheric hydrogen peroxide and organic hydroperoxides during PRIDE-PRD'06, China: their concentration, formation mechanism and contribution to secondary aerosols

    NASA Astrophysics Data System (ADS)

    Hua, W.; Chen, Z. M.; Jie, C. Y.; Kondo, Y.; Hofzumahaus, A.; Takegawa, N.; Chang, C. C.; Lu, K. D.; Miyazaki, Y.; Kita, K.; Wang, H. L.; Zhang, Y. H.; Hu, M.

    2008-11-01

    Atmospheric hydrogen peroxide (H2O2) and organic hydroperoxides were measured from 18 to 30 July in 2006 during the PRIDE-PRD'06 campaign at Backgarden, a rural site located 48 km north of Guangzhou, a mega-city in southern China. A ground-based instrument was used as a scrubbing coil collector to sample ambient air, followed by on-site analysis by high-performance liquid chromatography (HPLC) coupled with post-column derivatization and fluorescence detection. The H2O2 mixing ratio over the 13 days ranged from below the detection limit to a maximum of 4.6 ppbv, with a mean (and standard deviation) of (1.26±1.24) ppbv during the daytime (08:00 20:00 LT). Methyl hydroperoxide (MHP), with a maximum of 0.8 ppbv and a mean (and standard deviation) of (0.28±0.10) ppbv during the daytime, was the dominant organic hydroperoxide. Other organic peroxides, including bis-hydroxymethyl hydroperoxide (BHMP), peroxyacetic acid (PAA), hydroxymethyl hydroperoxide (HMHP), 1-hydroxy-ethyl hydroperoxide (1-HEHP) and ethyl hydroperoxide (EHP), were detected occasionally. The concentration of H2O2 exhibited a pronounced diurnal variation on sunny days, with a peak mixing ratio in the afternoon (12:00 18:00 LT), but lacked an explicit diurnal cycle on cloudy days. Sometimes a second peak mixing ratio of H2O2 was observed during the evening, suggesting that H2O2 was produced by the ozonolysis of alkenes. The diurnal variation profile of MHP was, in general, consistent with that of H2O2. The estimation indicated that in the morning the H2O2 detected was formed mostly through local photochemical activity, with the rest probably attributable to vertical transport. It is notable that relatively high levels of H2O2 and MHP were found in polluted air. The unexpectedly high level of HO2 radicals detected in this region can account for the production of hydroperoxides, while the moderate level of NOx suppressed the formation of hydroperoxides. High concentrations of hydroperoxides were detected

  8. The photochemistry of planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Dalgarno, A.

    1988-01-01

    Recent theoretical and observational investigations of photochemical processes in the atmospheres of the planets and their satellites are reviewed. Particular attention is given to the CO2-dominated atmospheres of Mars and Venus, the hydrogen-dominated atmospheres of the Jovian planets, the SO2 atmosphere of Io, and the massive atmospheres of Titan and Triton. The principal reaction paths involved are listed and briefly characterized, and numerical data on atmospheric compositions are given in tables.

  9. Removal of the process-induced fluorine associated to chemical vapor deposition of tungsten onto a polycrystalline silicon gate structure by heat treatment in a hydrogen-containing atmosphere

    NASA Astrophysics Data System (ADS)

    Eriksson, Th.; Carlsson, J.-O.; Mohadjeri, B.; Östling, M.; d'Heurle, F. M.; Petersson, C. S.; Keinonen, J.

    1990-09-01

    Tungsten was deposited from a gas mixture of hydrogen and tungsten hexafluoride onto a polycrystalline silicon gate structure in a chemical vapor deposition system. During the deposition process fluorine was also deposited as an undesired impurity. In order to remove the fluorine, heat treatments in the temperature range 550-1050 °C were performed in a hydrogen atmosphere. By this treatment it is possible to form volatile hydrofluoric acid and hence remove fluorine from the structure. Nuclear-resonance-broadening technique and secondary ion mass spectrometry were used for the analysis of fluorine. Fluorine was detected in all the samples except for the sample heat treated at 1050 °C. Moreover, etching of the polycrystalline silicon was observed. The gettering of fluorine, the etching of silicon and the observed formation of tungsten disilicide at 650 °C are discussed with respect to conceivable mechanisms. A thermodynamic study supporting the interpretations is also included.

  10. Carbon and hydrogen isotope composition and C-14 concentration in methane from sources and from the atmosphere: Implications for a global methane budget

    NASA Technical Reports Server (NTRS)

    Wahlen, Martin

    1994-01-01

    The topics covered include the following: biogenic methane studies; forest soil methane uptake; rice field methane sources; atmospheric measurements; stratospheric samples; Antarctica; California; and Germany.

  11. Hydrogen environment embrittlement of metals

    NASA Technical Reports Server (NTRS)

    Jewett, R. P.; Walter, R. J.; Chandler, W. T.; Frohmberg, R. P.

    1973-01-01

    Hydrogen environment embrittlement refers to metals stressed while exposed to a hydrogen atmosphere. Tested in air, even after exposure to hydrogen under pressure, this effect is not observed on similar specimens. Much high purity hydrogen is prepared by evaporation of liquid hydrogen, and thus has low levels for potential impurities which could otherwise inhibit or poison the absorbent reactions that are involved. High strength steels and nickel-base allows are rated as showing extreme embrittlement; aluminum alloys and the austenitic stainless steels, as well as copper, have negligible susceptibility to this phenomenon. The cracking that occurs appears to be a surface phenomenon, is unlike that of internal hydrogen embrittlement.

  12. Hydrogen production

    NASA Technical Reports Server (NTRS)

    England, C.; Chirivella, J. E.; Fujita, T.; Jeffe, R. E.; Lawson, D.; Manvi, R.

    1975-01-01

    The state of hydrogen production technology is evaluated. Specific areas discussed include: hydrogen production fossil fuels; coal gasification processes; electrolysis of water; thermochemical production of hydrogen; production of hydrogen by solar energy; and biological production of hydrogen. Supply options are considered along with costs of hydrogen production.

  13. Novel strategy to mitigate cathode catalyst degradation during air/air startup cycling via the atmospheric resistive switching mechanism of a hydrogen anode with a platinum catalyst supported on tantalum-doped titanium dioxide

    NASA Astrophysics Data System (ADS)

    Shintani, Haruhiko; Kojima, Yuya; Kakinuma, Katsuyoshi; Watanabe, Masahiro; Uchida, Makoto

    2015-10-01

    We propose a new strategy for alleviating the reverse current phenomenon using a unique "atmospheric resistive switching mechanism" (ARSM) of a metal oxide semiconductor support, such that the electrical resistivity changes depending on the gas atmosphere. The membrane-electrode assembly (MEA) using Ta-doped TiO2-supported platinum (Pt/Ta-TiO2) as the anode catalyst showed approximately one order of magnitude greater resistance in air than in hydrogen. The overpotential of the hydrogen oxidation reaction was negligible up to at least 1.5 A cm-2. The losses of electrochemically active surface area and carbon corrosion of the cathode catalyst during air/air startup cycling were significantly suppressed by the use of the Pt/Ta-TiO2 anode. The decrease in the degradation is attributed to a reduction of the reverse current due to a low oxygen reduction reaction rate at the anode, which showed high resistivity in air. These results demonstrate the effectiveness of the ARSM in mitigating cathode catalyst degradation during air/air startup cycling.

  14. Historical Doses from Tritiated Water and Tritiated Hydrogen Gas Released to the Atmosphere from Lawrence Livermore National Laboratory (LLNL). Part 2. LLNL Annual Site-specific Data, 1953 - 2003

    SciTech Connect

    Peterson, S R

    2005-03-07

    It is planned to use the tritium dose model, DCART (Doses from Chronic Atmospheric Releases of Tritium), to reconstruct dose to the hypothetical maximally exposed individual from annual routine releases of tritiated water (HTO) and tritiated hydrogen gas (HT) from all Lawrence Livermore National Laboratory (LLNL) facilities and from the Sandia National (SNL) Laboratory's Tritium Research Laboratory over the last fifty years. DCART has been described in Part 1 of ''Historical Doses From Tritiated Water And Tritiated Hydrogen Gas Released To The Atmosphere from Lawrence Livermore National Laboratory (LLNL)'' (UCRL-TR-205083). This report (Part 2) summarizes information about annual routine releases of tritium from LLNL (and SNL) since 1953. Historical records were used to derive facility-specific annual data (e.g., source terms, dilution factors, ambient air concentrations, meteorological data, including absolute humidity and rainfall, etc.) and their associated uncertainty distributions. These data will be used as input to DCART to calculate annual dose for each year of LLNL operations. Sources of information are carefully referenced, and assumptions are documented. Confidence on all data post-1974 is quite high. Prior to that, further adjustment to the estimated uncertainty may have to be made if more information comes to light.

  15. Polymer system for gettering hydrogen

    DOEpatents

    Shepodd, Timothy Jon; Whinnery, LeRoy L.

    2000-01-01

    A novel composition comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen.

  16. Polymer formulations for gettering hydrogen

    DOEpatents

    Shepodd, Timothy Jon; Whinnery, LeRoy L.

    1998-11-17

    A novel composition comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen.

  17. Polymer formulations for gettering hydrogen

    DOEpatents

    Shepodd, T.J.; Whinnery, L.L.

    1998-11-17

    A novel composition is described comprising organic polymer molecules having carbon-carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces. Organic polymers molecules containing carbon-carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble catalyst composition, comprising a hydrogenation catalyst and a catalyst support, preferably Pd supported on carbon, provide a hydrogen getter composition useful for removing hydrogen from enclosed spaces even in the presence of contaminants such as common atmospheric gases, water vapor, carbon dioxide, ammonia, oil mists, and water. The hydrogen getter composition disclosed herein is particularly useful for removing hydrogen from enclosed spaces containing potentially explosive mixtures of hydrogen and oxygen. 1 fig.

  18. Hydrogen systems

    SciTech Connect

    Veziroglu, T.N.; Zhu, Y.; Bao, D.

    1985-01-01

    This book presents the papers given at a symposium on hydrogen fuels. Topics considered at the symposium included hydrogen from fossil fuels, electrolysis, photolytic hydrogen generation, thermochemical and photochemical methods of hydrogen production, catalysts, hydrogen biosynthesis, novel and hybrid methods of hydrogen production, storage and handling, metal hydrides and their characteristics, utilization, hydrogen fueled internal combustion engines, hydrogen gas turbines, hydrogen flow and heat transfer, fuel cells, synthetic hydrocarbon fuels, thermal energy transfer, hydrogen purification, research programs, economics, primary energy sources, environmental impacts, and safety.

  19. Method for direct production of carbon disulfide and hydrogen from hydrocarbons and hydrogen sulfide feedstock

    SciTech Connect

    Miao, Frank Q.; Erekson, Erek James

    1998-12-01

    A method for converting hydrocarbons and hydrogen sulfide to carbon disulfide and hydrogen is provided comprising contacting the hydrocarbons and hydrogen sulfide to a bi-functional catalyst residing in a controlled atmosphere for a time and at a temperature sufficient to produce carbon disulfide and hydrogen. Also provided is a catalyst for converting carbon sulfides and hydrogen sulfides to gasoline range hydrocarbons comprising a mixture containing a zeolite catalyst and a hydrogenating catalyst.

  20. The atmosphere of Mars

    NASA Technical Reports Server (NTRS)

    Barth, C. A.

    1974-01-01

    The atmosphere of Mars is essentially a pure carbon dioxide atmosphere that contains a small and seasonably varying amount of water vapor. A number of minor constituents which arise from the interactions of solar radiation with water vapor and carbon dioxide include carbon monoxide, atomic oxygen, molecular oxygen, ozone, and atomic hydrogen. At the surface of Mars the atmospheric pressure is less than one hundredth of the pressure at the surface of the earth. Extensive cloud systems appear on Mars. The structure of the lower Martian atmosphere is discussed together with variations in the lower atmosphere and the characteristics of the upper atmosphere. Reactions of photochemistry are considered along with the atmospheric escape and interactions between the atmosphere and the polar caps.

  1. Research on coal reactivity: Making a comparison between hydrogenation with H-donor solvent and thermogravimetry in N{sub 2} atmosphere

    SciTech Connect

    Feng, J.; Li, W.Y.; Xie, K.C.; Liu, J.S.

    1998-12-31

    The objectives of this study are to seek answers to the following issues: Why are different ways used to analyze coal`s reactivity? Could different methods of measuring coal`s reactivity be comparable? Is there any relation among them? Two methods, coal hydrogenation and coal pyrolysis, are employed to evaluate coal`s reactivity. Seven kinds of coals from lignite to anthracite are studied. Activity energy calculated from results of thermogravimetry and the amount of hydrogen transferred during coal reaction with the H-donor THN are comparable. The methodological of canonical relation analysis was used to compare the two kinds of reactivity and result shows that these two kinds of reactivity have similitude to a certain extent.

  2. Electrochemical Hydrogen Compressor

    SciTech Connect

    Lipp, Ludwig

    2016-01-21

    Conventional compressors have not been able to meet DOE targets for hydrogen refueling stations. They suffer from high capital cost, poor reliability and pose a risk of fuel contamination from lubricant oils. This project has significantly advanced the development of solid state hydrogen compressor technology for multiple applications. The project has achieved all of its major objectives. It has demonstrated capability of Electrochemical Hydrogen Compression (EHC) technology to potentially meet the DOE targets for small compressors for refueling sites. It has quantified EHC cell performance and durability, including single stage hydrogen compression from near-atmospheric pressure to 12,800 psi and operation of EHC for more than 22,000 hours. Capital cost of EHC was reduced by 60%, enabling a path to meeting the DOE cost targets for hydrogen compression, storage and delivery ($2.00-2.15/gge by 2020).

  3. Organic chemistry in the atmosphere. [laboratory modeling of Titan atmosphere

    NASA Technical Reports Server (NTRS)

    Sagan, C.

    1974-01-01

    The existence of an at least moderately complex organic chemistry on Titan is stipulated based on clear evidence of methane, and at least presumptive evidence of hydrogen in its atmosphere. The ratio of methane to hydrogen is the highest of any atmosphere in the solar system. Irradiation of hydrogen/methane mixtures produces aromatic and aliphatic hydrocarbons. A very reasonable hypothesis assumes that the red cloud cover of Titan is made of organic chemicals. Two-carbon hydrocarbons experimentally produced from irradiated mixtures of methane, ammonia, water, and hydrogen bear out the possible organic chemistry of the Titanian environment.

  4. Method for absorbing hydrogen using an oxidation resisant organic hydrogen getter

    DOEpatents

    Shepodd, Timothy J.; Buffleben, George M.

    2009-02-03

    A composition for removing hydrogen from an atmosphere, comprising a mixture of a polyphenyl ether and a hydrogenation catalyst, preferably a precious metal catalyst, and most preferably platinum, is disclosed. This composition is stable in the presence of oxygen, will not polymerize or degrade upon exposure to temperatures in excess of 200.degree. C., or prolonged exposure to temperatures in the range of 100-300.degree. C. Moreover, these novel hydrogen getter materials can be used to efficiently remove hydrogen from mixtures of hydrogen/inert gas (e.g., He, Ar, N.sub.2), hydrogen/ammonia atmospheres, such as may be encountered in heat exchangers, and hydrogen/carbon dioxide atmospheres. Water vapor and common atmospheric gases have no adverse effect on the ability of these getter materials to absorb hydrogen.

  5. Hydrogen sensor

    DOEpatents

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  6. Complex hydrides for hydrogen storage

    DOEpatents

    Zidan, Ragaiy

    2006-08-22

    A hydrogen storage material and process of forming the material is provided in which complex hydrides are combined under conditions of elevated temperatures and/or elevated temperature and pressure with a titanium metal such as titanium butoxide. The resulting fused product exhibits hydrogen desorption kinetics having a first hydrogen release point which occurs at normal atmospheres and at a temperature between 50.degree. C. and 90.degree. C.

  7. Hydrogenation apparatus

    DOEpatents

    Friedman, Joseph [Encino, CA; Oberg, Carl L [Canoga Park, CA; Russell, Larry H [Agoura, CA

    1981-01-01

    Hydrogenation reaction apparatus comprising a housing having walls which define a reaction zone and conduits for introducing streams of hydrogen and oxygen into the reaction zone, the oxygen being introduced into a central portion of the hydrogen stream to maintain a boundary layer of hydrogen along the walls of the reaction zone. A portion of the hydrogen and all of the oxygen react to produce a heated gas stream having a temperature within the range of from 1100.degree. to 1900.degree. C., while the boundary layer of hydrogen maintains the wall temperature at a substantially lower temperature. The heated gas stream is introduced into a hydrogenation reaction zone and provides the source of heat and hydrogen for a hydrogenation reaction. There also is provided means for quenching the products of the hydrogenation reaction. The present invention is particularly suitable for the hydrogenation of low-value solid carbonaceous materials to provide high yields of more valuable liquid and gaseous products.

  8. Role of hydrogen diffusion in temperature-induced transformation of carbon nanostructures deposited on metallic substrates by using a specially designed fused hollow cathode cold atmospheric pressure plasma source

    NASA Astrophysics Data System (ADS)

    Sharma, Bikash; Kar, R.; Pal, Arup R.; Shilpa, R. K.; Dusane, R. O.; Patil, D. S.; Suryawanshi, S. R.; More, M. A.; Sinha, S.

    2017-04-01

    Carbon nanofibers (CNFs) and carbon nanotubes (CNTs) are grown on inconel substrates under two different experimental conditions using atmospheric pressure glow discharge radio-frequency (RF) PECVD process. A specially designed hollow cathode is used for this plasma generation. The growth is carried out at 610 and 660 °C substrate temperatures on inconel substrates. Our results show that CNFs and CNTs could be synthesized at 610 and 660 °C respectively irrespective of pre-treatment methods in either set. HRTEM results indicate that a temperature-induced transformation of CNFs into CNTs occur when the growth temperature is raised from 610 to 660 °C. With the help of characterization results and a schematic model, it is shown how an increase in hydrogen diffusion (~44% increase) plays a pivotal role in this transformation by providing a sink for hydrogen atoms. Field emission results show that most defective CNFs contribute to the maximum emission current density. This better field emission behavior is explained on the basis that the outer surfaces of CNFs are more defective due to the presence of the open edges of the graphene planes, which results in better field emission from the outer surfaces of the CNFs.

  9. Hydrogen Isotopic Composition of Arctic and Atmospheric CH4 Determined by a Portable Near-Infrared Cavity Ring-Down Spectrometer with a Cryogenic Pre-Concentrator

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Lehmann, Kevin K.; Peng, Y.; Pratt, L. M.; White, J. R.; Cadieux, S. B.; Sherwood Lollar, B.; Lacrampe-Couloume, G.; Onstott, T. C.

    2016-10-01

    In this study, near-infrared continuous wave cavity ring-down spectroscopy was applied to the measurement of the δ2H of methane (CH4). The cavity ring-down spectrometer (CRDS) system consisted of multiple DFB laser diodes to optimize selection of spectral line pairs. By rapidly switching measurements between spectral line peaks and the baseline regions, the long-term instrumental drift was minimized, substantially increasing measurement precision. The CRDS system coupled with a cryogenic pre-concentrator measured the δ2H of terrestrial atmospheric CH4 from 3 standard liters of air with a precision of ±1.7‰. The rapidity with which both C and H isotopic measurements of CH4 can be made with the CRDS will enable hourly monitoring of diurnal variations in terrestrial atmospheric CH4 signatures that can be used to increase the resolution of global climate models for the CH4 cycle. Although the current instrument is not capable of measuring the δ2H of 10 ppbv of martian CH4, current technology does exist that could make this feasible for future spaceflight missions. As biological and abiotic CH4 sources have overlapping carbon isotope signatures, dual-element (C and H) analysis is key to reliable differentiation of these sources. Such an instrument package would therefore offer improved ability to determine whether or not the CH4 recently detected in the martian atmosphere is biogenic in origin.

  10. Molecular hydrogen (H2) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H2

    NASA Astrophysics Data System (ADS)

    Vollmer, M. K.; Walter, S.; Bond, S. W.; Soltic, P.; Röckmann, T.

    2010-06-01

    Molecular hydrogen (H2), its isotopic signature (deuterium/hydrogen, δD), carbon monoxide (CO), and other compounds were studied in the exhaust of a passenger car engine fuelled with gasoline or methane and run under variable air-fuel ratios and operating modes. H2 and CO concentrations were largely reduced downstream of the three-way catalytic converter (TWC) compared to levels upstream, and showed a strong dependence on the air-fuel ratio (expressed as lambda, λ). The isotopic composition of H2 ranged from δD = -140‰ to δD = -195‰ upstream of the TWC but these values decreased to -270‰ to -370‰ after passing through the TWC. Post-TWC δD values for the fuel-rich range showed a strong dependence on TWC temperature with more negative δD for lower temperatures. These effects are attributed to a rapid temperature-dependent H-D isotope equilibration between H2 and water (H2O). In addition, post TWC δD in H2 showed a strong dependence on the fraction of removed H2, suggesting isotopic enrichment during catalytic removal of H2 with enrichment factors (ɛ) ranging from -39.8‰ to -15.5‰ depending on the operating mode. Our results imply that there may be considerable variability in real-world δD emissions from vehicle exhaust, which may mainly depend on TWC technology and exhaust temperature regime. This variability is suggestive of a δD from traffic that varies over time, by season, and by geographical location. An earlier-derived integrated pure (end-member) δD from anthropogenic activities of -270‰ (Rahn et al., 2002) can be explained as a mixture of mainly vehicle emissions from cold starts and fully functional TWCs, but enhanced δD values by >50‰ are likely for regions where TWC technology is not fully implemented. Our results also suggest that a full hydrogen isotope analysis on fuel and exhaust gas may greatly aid at understanding process-level reactions in the exhaust gas, in particular in the TWC.

  11. Molecular hydrogen (H2) emissions and their isotopic signatures (H/D) from a motor vehicle: implications on atmospheric H2

    NASA Astrophysics Data System (ADS)

    Vollmer, M. K.; Walter, S.; Bond, S. W.; Soltic, P.; Röckmann, T.

    2010-02-01

    Molecular hydrogen (H2), its isotopic signature (deuterium/hydrogen, δD), carbon monoxide (CO) and other compounds were studied in the exhaust of a passenger car engine fuelled with gasoline or methane and run under variable air-fuel ratios and operating modes. H2 and CO concentrations were largely reduced downstream of the three-way catalytic converter (TWC) compared to levels upstream, and showed a strong dependence on the air-fuel ratio (expressed as lambda, λ). The isotopic composition of H2 ranged from δD=-140‰ to δD=-195‰ upstream of the TWC but these values decreased to -270‰ to -370‰ after passing through the TWC. Post-TWC δD values for the fuel-rich range showed a strong dependence on TWC temperature with more negative δD for lower temperatures. These effects are attributed to a rapid temperature-dependent H-D isotope equilibration between H2 and water (H2O). In addition, post TWC δD in H2 showed a strong dependence on the fraction of removed H2, suggesting isotopic enrichment during catalytic removal of H2 with enrichment factors (ɛ) ranging from -39.8‰ to -15.5‰ depending on the operating mode. Our results imply that there may be considerable variability in real-world δD emissions from vehicle exhaust, which may mainly depend on TWC technology and exhaust temperature regime. This variability is suggestive of a δD from traffic that varies over time, by season, and by geographical location. An earlier-derived integrated pure (end-member) δD from anthropogenic activities of -270‰ (Rahn et al., 2002) can be explained as a mixture of mainly vehicle emissions from cold starts and fully functional TWCs, but enhanced δD values by >50‰ are likely for regions where TWC technology is not fully implemented. Our results also suggest that a full hydrogen isotope analysis on fuel and exhaust gas may greatly aid at understanding process-level reactions in the exhaust gas, in particular in the TWC.

  12. Historical Doses from Tritiated Water and Tritiated Hydrogen Gas Relesed to the Atmosphere from Lawrence Livermore National Laboratory (LLNL) Part 1. Description of Tritium Dose Model (DCART) for Chronic Releases from LLNL

    SciTech Connect

    Peterson, S

    2004-06-30

    DCART (Doses from Chronic Atmospheric Releases of Tritium) is a spreadsheet model developed at Lawrence Livermore National Laboratory (LLNL) that calculates doses from inhalation of tritiated hydrogen gas (HT), inhalation and skin absorption of tritiated water (HTO), and ingestion of HTO and organically bound tritium (OBT) to adult, child (age 10), and infant (age 6 months to 1 year) from routine atmospheric releases of HT and HTO. DCART is a deterministic model that, when coupled to the risk assessment software Crystal Ball{reg_sign}, predicts doses with a 95th percentile confidence interval. The equations used by DCART are described and all distributions on parameter values are presented. DCART has been tested against the results of other models and several sets of observations in the Tritium Working Group of the International Atomic Energy Agency's Biosphere Modeling and Assessment Programme. The version of DCART described here has been modified to include parameter values and distributions specific to conditions at LLNL. In future work, DCART will be used to reconstruct dose to the hypothetical maximally exposed individual from annual routine releases of HTO and HT from all LLNL facilities and from the Sandia National Laboratory's Tritium Research Laboratory over the last fifty years.

  13. Historical Doses from Tritiated Water and Tritiated Hydrogen Gas Released to the Atmosphere from Lawrence Livermore National Laboratory (LLNL) Part 1. Description of Tritium Dose Model (DCART) for Routine Releases from LLNL

    SciTech Connect

    Peterson, S R

    2006-09-27

    DCART (Doses from Chronic Atmospheric Releases of Tritium) is a spreadsheet model developed at Lawrence Livermore National Laboratory (LLNL) that calculates doses from inhalation of tritiated hydrogen gas (HT), inhalation and skin absorption of tritiated water (HTO), and ingestion of HTO and organically bound tritium (OBT) to adult, child (age 10), and infant (age 6 months to 1 year) from routine atmospheric releases of HT and HTO. DCART is a deterministic model that, when coupled to the risk assessment software Crystal Ball{reg_sign}, predicts doses with a 95% confidence interval. The equations used by DCART are described and all distributions on parameter values are presented. DCART has been tested against the results of other models and several sets of observations in the Tritium Working Groups of the International Atomic Energy Agency's programs, Biosphere Modeling and Assessment and Environmental Modeling for Radiation Safety. The version of DCART described here has been modified to include parameter values and distributions specific to conditions at LLNL. In future work, DCART will be used to reconstruct dose to the hypothetical maximally exposed individual from annual routine releases of HTO and HT from all LLNL facilities and from the Sandia National Laboratory's Tritium Research Laboratory over the last fifty years.

  14. Exploration of the Potential Energy Surfaces, Prediction of Atmospheric Concentrations, and Prediction of Vibrational Spectra for the HO2···(H2O)n (n=1-2) Hydrogen Bonded Complexes

    PubMed Central

    Alongi, Kristin S.; Dibble, Theodore S.; Shields, George C.; Kirschner, Karl N.

    2008-01-01

    The hydroperoxy radical (HO2) plays a critical role in Earth’s atmospheric chemistry as a component of many important reactions. The self-reaction of hydroperoxy radicals in the gas phase is strongly affected by the presence of water vapor. In this work we explore the potential energy surfaces of hydroperoxy radicals hydrogen bonded to one or two water molecules, and predict atmospheric concentrations and vibrational spectra of these complexes. We predict that when the HO2 concentration is on the order of 108 molecules·cm-3 at 298K, that the number of HO2···H2O complexes is on the order of 107 molecules·cm-3 and the number of HO2···(H2O)2 complexes is on the order of 106 molecules·cm-3. Using the computed abundance of HO2···H2O, we predict that, at 298K, the bimolecular rate constant for HO2···H2O + HO2 is about ten times that for HO2 + HO2. PMID:16526652

  15. Hydrogen-powered flight

    NASA Technical Reports Server (NTRS)

    Smith, Timothy D.

    2005-01-01

    As the Nation moves towards a hydrogen economy the shape of aviation will change dramatically. To accommodate a switch to hydrogen the aircraft designs, propulsion, and power systems will look much different than the systems of today. Hydrogen will enable a number of new aircraft capabilities from high altitude long endurance remotely operated aircraft (HALE ROA) that will fly weeks to months without refueling to clean, zero emissions transport aircraft. Design and development of new hydrogen powered aircraft have a number of challenges which must be addressed before an operational system can become a reality. While the switch to hydrogen will be most outwardly noticeable in the aircraft designs of the future, other significant changes will be occurring in the environment. A switch to hydrogen for aircraft will completely eliminate harmful greenhouse gases such as carbon monoxide (CO), carbon dioxide (CO2), sulfur oxides (SOx), unburnt hydrocarbons and smoke. While these aircraft emissions are a small percentage of the amount produced on a daily basis, their placement in the upper atmosphere make them particularly harmful. Another troublesome gaseous emission from aircraft is nitrogen oxides (NOx) which contribute to ozone depletion in the upper atmosphere. Nitrogen oxide emissions are produced during the combustion process and are primarily a function of combustion temperature and residence time. The introduction of hydrogen to a gas turbine propulsion system will not eliminate NOx emissions; however the wide flammability range will make low NOx producing, lean burning systems feasible. A revolutionary approach to completely eliminating NOx would be to fly all electric aircraft powered by hydrogen air fuel cells. The fuel cells systems would only produce water, which could be captured on board or released in the lower altitudes. Currently fuel cell systems do not have sufficient energy densities for use in large aircraft, but the long term potential of eliminating

  16. Historical Doses from Tritiated Water and Tritiated Hydrogen Gas Released to the Atmosphere from Lawrence Livermore National Laboratory (LLNL). Part 3. Routine Releases, 1973 - 2005

    SciTech Connect

    Peterson, S

    2007-08-15

    Annual mean concentrations of tritium in air moisture, calculated from data obtained from an air tritium sampler near the LLNL Discovery Center, were compared with annual mean air moisture concentrations predicted from atmospheric releases of tritium for the years 1973 through 2005. The 95% confidence intervals on the predictions and observations usually overlapped. When the distributions of predictions and observations were different, predictions were higher. Using both the observed and predicted air concentrations as input to the tritium dose model, DCART, annual doses to a hypothetical adult, child (age 10) and infant (age 6 months to 1 year) assumed to be living at LLNL's Discovery Center were calculated. Although the doses based on predicted air concentrations tended to be higher, they were nevertheless indistinguishable from doses based on observed air concentrations when uncertainties were taken into account. Annual doses, calculated by DCART and based on observed and predicted air concentrations, were compared with historical tritium doses reported annually by LLNL. Although the historical doses were calculated using various assumptions over the years, their agreement with the DCART predictions is remarkable. The Discovery Center was not the location of the site-wide maximally exposed individual (SWMEI) from 1974 through 1978. However, doses at the location of the SW-MEI for those years were indistinguishable from those at the Discovery Center when uncertainties were taken into account. The upper confidence limits for all doses were always well below the current regulatory limit for dose to a member of the public (100 {micro}Sv or 10 mrem per year) from atmospheric releases (40 CFR Part 61, Subpart H). Based on observed air concentrations, the 97.5% confidence limit on the cumulative dose to the hypothetical person born in 1973 and living through 2005 at the Discovery Center was 150 {micro}Sv (15 mrem), while that of the hypothetical adult who spent his

  17. Hydrogen in Martian Meteorites

    NASA Technical Reports Server (NTRS)

    Peslier, A. H.; Hervig, R.; Irving, T.

    2017-01-01

    Most volatile studies of Mars have targeted its surface via spacecraft and rover data, and have evidenced surficial water in polar caps and the atmosphere, in the presence of river channels, and in the detection of water bearing minerals. The other focus of Martian volatile studies has been on Martian meteorites which are all from its crust. Most of these studies are on hydrous phases like apatite, a late-stage phase, i.e. crystallizing near the end of the differentiation sequence of Martian basalts and cumulates. Moreover, calculating the water content of the magma a phosphate crystallized from is not always possible, and yet is an essential step to estimate how much water was present in a parent magma and its source. Water, however, is primarily dissolved in the interiors of differentiated planets as hydrogen in lattice defects of nominally anhydrous minerals (olivine, pyroxene, feldspar) of the crust and mantle. This hydrogen has tremendous influence, even in trace quantities, on a planet's formation, geodynamics, cooling history and the origin of its volcanism and atmosphere as well as its potential for life. Studies of hydrogen in nominally anhydrous phases of Martian meteorites are rare. Measuring water contents and hydrogen isotopes in well-characterized nominally anhydrous minerals of Martian meteorites is the goal of our study. Our work aims at deciphering what influences the distribution and origin of hydrogen in Martian minerals, such as source, differentiation, degassing and shock.

  18. Historical Doses from Tritiated Water and Tritiated Hydrogen Gas Released to the Atmosphere from Lawrence Livermore National Laboratory (LLNL). Part 5. Accidental Releases

    SciTech Connect

    Peterson, S

    2007-08-15

    Over the course of fifty-three years, LLNL had six acute releases of tritiated hydrogen gas (HT) and one acute release of tritiated water vapor (HTO) that were too large relative to the annual releases to be included as part of the annual releases from normal operations detailed in Parts 3 and 4 of the Tritium Dose Reconstruction (TDR). Sandia National Laboratories/California (SNL/CA) had one such release of HT and one of HTO. Doses to the maximally exposed individual (MEI) for these accidents have been modeled using an equation derived from the time-dependent tritium model, UFOTRI, and parameter values based on expert judgment. All of these acute releases are described in this report. Doses that could not have been exceeded from the large HT releases of 1965 and 1970 were calculated to be 43 {micro}Sv (4.3 mrem) and 120 {micro}Sv (12 mrem) to an adult, respectively. Two published sets of dose predictions for the accidental HT release in 1970 are compared with the dose predictions of this TDR. The highest predicted dose was for an acute release of HTO in 1954. For this release, the dose that could not have been exceeded was estimated to have been 2 mSv (200 mrem), although, because of the high uncertainty about the predictions, the likely dose may have been as low as 360 {micro}Sv (36 mrem) or less. The estimated maximum exposures from the accidental releases were such that no adverse health effects would be expected. Appendix A lists all accidents and large routine puff releases that have occurred at LLNL and SNL/CA between 1953 and 2005. Appendix B describes the processes unique to tritium that must be modeled after an acute release, some of the time-dependent tritium models being used today, and the results of tests of these models.

  19. Method of generating hydrogen and using the generated hydrogen

    SciTech Connect

    Papineau, R. I.

    1985-10-15

    The present invention is directed to a hydrogen generating system which produces hydrogen instantaneously from water ready for use upon demand. The system includes a reactor that has reaction zones wherein catalyst and elevated temperatures generate hydrogen from steam. The zones in the reactor can be in the form of tubes about a heat generating chamber, and the zones are adapted to be interconnected to each other, to atmosphere, and to the source of steam, all to maximize the generation of hydrogen by providing a reactor of optimum flexibility. The present invention also is directed to systems which include the hydrogen generating system and which utilize the generated hydrogen as a fuel or a chemical.

  20. Simultaneous measurement of nitrogen and hydrogen dissociation from vacuum ultraviolet self-absorption spectroscopy in a developing low temperature plasma at atmospheric pressure

    SciTech Connect

    Laity, George; Fierro, Andrew; Dickens, James; Neuber, Andreas; Frank, Klaus

    2013-05-06

    We demonstrate a method for determining the dissociation density of N and H atoms present in a developing low temperature plasma, based on the emission and self-absorption of vacuum ultraviolet radiation produced from the plasma. Spark plasmas are produced via pulsed discharge in N{sub 2}/H{sub 2} mixtures at atmospheric pressure, where information on the dissociated densities of the constituent gas molecules is desired without employing invasive diagnostic techniques. By analyzing the self-absorption line profile of 121.5 nm Lyman-{alpha} H radiation emitted within the first {approx}1.0 mm of plasma near the anode tip, a peak dissociated H atom concentration of 5.6 Multiplication-Sign 10{sup 17} cm{sup -3} was observed {approx}100 ns into spark formation, with an estimated electron density of 2.65 Multiplication-Sign 10{sup 18} cm{sup -3} determined from Stark broadening. Similarly, simultaneous line fitting of the N 120.0/124.3 nm emission profiles revealed a peak dissociated N atom concentration of 3.8 Multiplication-Sign 10{sup 17} cm{sup -3} during the same discharge period.

  1. Using stable isotopes of hydrogen to quantify biogenic and thermogenic atmospheric methane sources: A case study from the Colorado Front Range

    NASA Astrophysics Data System (ADS)

    Townsend-Small, Amy; Botner, E. Claire; Jimenez, Kristine L.; Schroeder, Jason R.; Blake, Nicola J.; Meinardi, Simone; Blake, Donald R.; Sive, Barkley C.; Bon, Daniel; Crawford, James H.; Pfister, Gabriele; Flocke, Frank M.

    2016-11-01

    Global atmospheric concentrations of methane (CH4), a powerful greenhouse gas, are increasing, but because there are many natural and anthropogenic sources of CH4, it is difficult to assess which sources may be increasing in magnitude. Here we present a data set of δ2H-CH4 measurements of individual sources and air in the Colorado Front Range, USA. We show that δ2H-CH4, but not δ13C, signatures are consistent in air sampled downwind of landfills, cattle feedlots, and oil and gas wells in the region. Applying these source signatures to air in ground and aircraft samples indicates that at least 50% of CH4 emitted in the region is biogenic, perhaps because regulatory restrictions on leaking oil and natural gas wells are helping to reduce this source of CH4. Source apportionment tracers such as δ2H may help close the gap between CH4 observations and inventories, which may underestimate biogenic as well as thermogenic sources.

  2. Hydrogen generator

    SciTech Connect

    Adlhart, O. J.

    1985-04-23

    This disclosure relates to a replaceable cartridge hydrogen generator of the type which relies at least partially on the process of anodic corrosion to produce hydrogen. A drum contains a plurality of the cartridges.

  3. Hydrogen Generator

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A unit for producing hydrogen on site is used by a New Jersey Electric Company. The hydrogen is used as a coolant for the station's large generator; on-site production eliminates the need for weekly hydrogen deliveries. High purity hydrogen is generated by water electrolysis. The electrolyte is solid plastic and the control system is electronic. The technology was originally developed for the Gemini spacecraft.

  4. Hydrogen Production

    SciTech Connect

    2014-09-01

    This 2-page fact sheet provides a brief introduction to hydrogen production technologies. Intended for a non-technical audience, it explains how different resources and processes can be used to produce hydrogen. It includes an overview of research goals as well as “quick facts” about hydrogen energy resources and production technologies.

  5. Hydrogen Storage

    SciTech Connect

    2008-11-01

    This 2-page fact sheet provides a brief introduction to hydrogen storage technologies. Intended for a non-technical audience, it explains the different ways in which hydrogen can be stored, as well as the technical challenges and research goals for storing hydrogen on board a vehicle.

  6. Historical Doses from Tritiated Water and Tritiated Hydrogen Gas Released to the Atmosphere from Lawrence Livermore National Laboratory (LLNL). Part 6. Summary

    SciTech Connect

    Peterson, S

    2007-09-05

    Throughout fifty-three years of operations, an estimated 792,000 Ci (29,300 TBq) of tritium have been released to the atmosphere at the Livermore site of Lawrence Livermore National Laboratory (LLNL); about 75% was tritium gas (HT) primarily from the accidental releases of 1965 and 1970. Routine emissions contributed slightly more than 100,000 Ci (3,700 TBq) HT and about 75,000 Ci (2,800 TBq) tritiated water vapor (HTO) to the total. A Tritium Dose Reconstruction was undertaken to estimate both the annual doses to the public for each year of LLNL operations and the doses from the few accidental releases. Some of the dose calculations were new, and the others could be compared with those calculated by LLNL. Annual doses (means and 95% confidence intervals) to the potentially most exposed member of the public were calculated for all years using the same model and the same assumptions. Predicted tritium concentrations in air were compared with observed mean annual concentrations at one location from 1973 onwards. Doses predicted from annual emissions were compared with those reported in the past by LLNL. The highest annual mean dose predicted from routine emissions was 34 {micro}Sv (3.4 mrem) in 1957; its upper confidence limit, based on very conservative assumptions about the speciation of the release, was 370 {micro}Sv (37 mrem). The upper confidence limits for most annual doses were well below the current regulatory limit of 100 {micro}Sv (10 mrem) for dose to the public from release to the atmosphere; the few doses that exceeded this were well below the regulatory limits of the time. Lacking the hourly meteorological data needed to calculate doses from historical accidental releases, ingestion/inhalation dose ratios were derived from a time-dependent accident consequence model that accounts for the complex behavior of tritium in the environment. Ratios were modified to account for only those foods growing at the time of the releases. The highest dose from an

  7. Atmospheric Pseudohalogen Chemistry

    NASA Technical Reports Server (NTRS)

    Lary, David John

    2004-01-01

    Hydrogen cyanide is not usually considered in atmospheric chemical models. The paper presents three reasons why hydrogen cyanide is likely to be significant for atmospheric chemistry. Firstly, HCN is a product and marker of biomass burning. Secondly, it is also likely that lightning is producing HCN, and as HCN is sparingly soluble it could be a useful long-lived "smoking gun" marker of lightning activity. Thirdly, the chemical decomposition of HCN leads to the production of small amounts of the cyanide (CN) and NCO radicals. The NCO radical can be photolyzed in the visible portion of the spectrum yielding nitrogen atoms (N). The production of nitrogen atoms is significant as it leads to the titration of total nitrogen from the atmosphere via N+N->N2, where N2 is molecular nitrogen.

  8. Historical Doses from Tritiated Water and Tritiated Hydrogen Gas Released to the Atmosphere from Lawrence Livermore National Laboratory (LLNL). Part 2. LLNL Annual Site-specific Data, 1953 - 2005

    SciTech Connect

    Peterson, S

    2007-08-15

    Historical information about tritium released routinely and accidentally from all Livermore Site Lawrence Livermore National Laboratory (LLNL) facilities and from the Tritium Research Laboratory of Sandia National Laboratories/California (SNL/CA) between 1953 through 2005 has been compiled and summarized in this report. Facility-specific data (annual release rates and dilution factors) have been derived from the historical information. These facility-specific data are needed to calculate annual doses to a hypothetical site-wide maximally exposed individual from routine releases of tritiated water (HTO) and tritiated hydrogen gas (HT) to the atmosphere. Doses can also be calculated from observed air tritium concentrations, and mean annual values for one air tritium sampling location are presented. Other historical data relevant to a dose reconstruction (e.g., meteorological data, including absolute humidity and rainfall) are also presented. Sources of information are carefully referenced, and assumptions are documented. Uncertainty distributions have been estimated for all parameter values. Confidence in data post-1974 is high.

  9. Hydrogen ion study by incoherent scatter (IS) method: comparison of results taken by Kharkov IS radar with data from Arecibo and Millstone Hill radars, atmosphere explorer satellites and model

    NASA Astrophysics Data System (ADS)

    Taran, V. I.; Grigorenko, Ye. I.

    2003-04-01

    Investigation of hydrogen ion behavior in topside ionosphere with the Kharkov IS radar is conducted by the POLITE CEDAR program. Program aim is the study of flight ion morphology and dynamics for refinement of the global topside ionosphere models and forecast of the 'space weather'. In this paper, the H+ density data of radars at Kharkov, Arecibo and Millstone Hill are compared at altitudes up to 1000-1300 km for winter and summer, minimum and maximum of solar activity. The measurements showed that height and diurnal variations of H+ concentration over eastern and western hemispheres were generally in close agreement, It is revealed a strong longitudinal variation of H+ ion fraction that is accounted for different magnetic flux tube volumes due to the offset between the geographic and geomagnetic poles. The Kharkov radar data are also compared with results taken from the Atmosphere Explorer (AE) database and FLIP model calculations, for midlatitude region, noon and midnight local time, at solar minimum. Comparisons show that H+ height distributions good agrees and corresponds close conditions of ionosphere-plasmasphere interaction. At the same time the model and AE data are lower than mesaured densities at Kharkov that can be explained by geophysical condition difference.

  10. Hydrogenation apparatus

    DOEpatents

    Friedman, J.; Oberg, C. L.; Russell, L. H.

    1981-06-23

    Hydrogenation reaction apparatus is described comprising a housing having walls which define a reaction zone and conduits for introducing streams of hydrogen and oxygen into the reaction zone, the oxygen being introduced into a central portion of the hydrogen stream to maintain a boundary layer of hydrogen along the walls of the reaction zone. A portion of the hydrogen and all of the oxygen react to produce a heated gas stream having a temperature within the range of from 1,100 to 1,900 C, while the boundary layer of hydrogen maintains the wall temperature at a substantially lower temperature. The heated gas stream is introduced into a hydrogenation reaction zone and provides the source of heat and hydrogen for a hydrogenation reaction. There also is provided means for quenching the products of the hydrogenation reaction. The present invention is particularly suitable for the hydrogenation of low-value solid carbonaceous materials to provide high yields of more valuable liquid and gaseous products. 2 figs.

  11. Color Changing Hydrogen Sensors

    NASA Technical Reports Server (NTRS)

    Roberson, Luke B.; Williams, Martha; Captain, Janine E.; Mohajeri, Nahid; Raissi, Ali

    2015-01-01

    During the Space Shuttle Program, one of the most hazardous operation that occurred was the loading of liquid hydrogen (LH2) during fueling operations of the spacecraft. Due to hydrogen's low explosive limit, any amount leaked could lead to catastrophic event. Hydrogen's chemical properties make it ideal as a rocket fuel; however, the fuel is deemed unsafe for most commercial use because of the inability to easily detect the gas leaking. The increased use of hydrogen over traditional fossil fuels would reduce greenhouse gases and America's dependency on foreign oil. Therefore a technology that would improve safety at NASA and in the commercial sector while creating a new economic sector would have a huge impact to NASA's mission. The Chemochromic Detector for sensing hydrogen gas leakage is a color-changing detector that is useful in any application where it is important to know not only the presence but also the location of the hydrogen gas leak. This technology utilizes a chemochromicpigment and polymer matrix that can be molded or spun into rigid or pliable shapes useable in variable temperature environments including atmospheres of inert gas, hydrogen gas, or mixtures of gases. A change in color of the detector material indicates where gaseous hydrogen leaks are occurring. The irreversible sensor has a dramatic color change from beige to dark grey and remains dark grey after exposure. A reversible pigment changes from white to blue in the presence of hydrogen and reverts back to white in the presence of oxygen. Both versions of the sensor's pigments were comprised of a mixture of a metal oxide substrate and a hydro-chromic compound (i.e., the compound that changed color in the presence of hydrogen) and immediately notified the operator of the presence of low levels of hydrogen. The detector can be used in a variety of formats including paint, tape, caulking, injection molded parts, textiles and fabrics, composites, and films. This technology brings numerous

  12. Spontaneous combustion of hydrogen

    NASA Technical Reports Server (NTRS)

    Nusselt, Wilhelm; Pothmann, PH

    1923-01-01

    It is shown by the author's experiments that hydrogen which escapes to the atmosphere through openings in the system may burn spontaneously if it contains dust. Purely thermal reasoning can not account for the combustion. It seems to be rather an electrical ignition. In order to determine whether the cause of the spontaneous ignition was thermo-chemical, thermo-mechanical, or thermo-electrical, the experiments in this paper were performed.

  13. Solar hydrogen production: renewable hydrogen production by dry fuel reforming

    NASA Astrophysics Data System (ADS)

    Bakos, Jamie; Miyamoto, Henry K.

    2006-09-01

    SHEC LABS - Solar Hydrogen Energy Corporation constructed a pilot-plant to demonstrate a Dry Fuel Reforming (DFR) system that is heated primarily by sunlight focusing-mirrors. The pilot-plant consists of: 1) a solar mirror array and solar concentrator and shutter system; and 2) two thermo-catalytic reactors to convert Methane, Carbon Dioxide, and Water into Hydrogen. Results from the pilot study show that solar Hydrogen generation is feasible and cost-competitive with traditional Hydrogen production. More than 95% of Hydrogen commercially produced today is by the Steam Methane Reformation (SMR) of natural gas, a process that liberates Carbon Dioxide to the atmosphere. The SMR process provides a net energy loss of 30 to 35% when converting from Methane to Hydrogen. Solar Hydrogen production provides a 14% net energy gain when converting Methane into Hydrogen since the energy used to drive the process is from the sun. The environmental benefits of generating Hydrogen using renewable energy include significant greenhouse gas and criteria air contaminant reductions.

  14. Hydrogen energy progress 5678

    SciTech Connect

    Veziroglu, T.N. )

    1990-01-01

    This book covers the proceedings of the 8th World Hydrogen Energy Conference, and includes: international hydrogen energy programs; hydrogen production; storage of hydrogen; hydrogen transmission and distribution; combustion systems/hydrogen engines; fuel cells; and synfuel production.

  15. Hydrogen generator

    SciTech Connect

    Hansen, J.R.

    1984-06-19

    A hydrogen generator decomposes water into hydrogen and oxygen, and includes an induction coil which is electrically heated to a temperature sufficient to decompose water passing therethrough. A generator coil is connected in communicating relation to the induction coil, and is positioned in a fire resistant crucible containing ferrous oxide pellets. Oxygen and hydrogen produced by decomposition of water pass through the ferrous oxide pellets where the oxygen reacts with the ferrous oxide and the hydrogen is burned to produce heat for heating a building, such as a conventional home.

  16. Reversible Chemochromic Hydrogen Detectors

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Florida Solar Energy Center (FSEC), affiliated with the University of Central Florida, has invented a reversible pigment that changes from light beige to blue when exposed to hydrogen and back to light beige when exposed to atmospheric oxygen. In laboratory and environmental studies, the FSEC pigment in its tape form failed to change color adequately when exposed to hydrogen after one day of exposure at Kennedy Space Center's Beach Corrosion Test Facility. The reversible hydrogen-detecting tape also lost its ability to change color after being placed in an environmental chamber at 45 C for one day. The first attempts at extruding the reversible pigment into various polymers were unsuccessful because of the pigment's poor thermal stability. The goal of this project was to formulate a pigment with improved thermal and environmental stability for extrusion into a variety of appropriate polymer matrices. The formulation of the reversible hydrogen-detecting pigment was modified by removing one reagent and chemically modifying the hydrogen sensitive ingredient. This was intended to improve the hydrophobicity of the pigment and alter the thermal degradation mechanism.

  17. Hydrogen Bibliography

    SciTech Connect

    Not Available

    1991-12-01

    The Hydrogen Bibliography is a compilation of research reports that are the result of research funded over the last fifteen years. In addition, other documents have been added. All cited reports are contained in the National Renewable Energy Laboratory (NREL) Hydrogen Program Library.

  18. Differential atmospheric tritium sampler

    DOEpatents

    Griesbach, Otto A.; Stencel, Joseph R.

    1990-01-01

    An atmospheric tritium sampler is provided which uses a carrier gas comprised of hydrogen gas and a diluting gas, mixed in a nonexplosive concentration. Sample air and carrier gas are drawn into and mixed in a manifold. A regulator meters the carrier gas flow to the manifold. The air sample/carrier gas mixture is pulled through a first moisture trap which adsorbs water from the air sample. The mixture then passes through a combustion chamber where hydrogen gas in the form of H.sub.2 or HT is combusted into water. The manufactured water is transported by the air stream to a second moisture trap where it is adsorbed. The air is then discharged back into the atmosphere by means of a pump.

  19. Differential atmospheric tritium sampler

    DOEpatents

    Griesbach, O.A.; Stencel, J.R.

    1987-10-02

    An atmospheric tritium sampler is provided which uses a carrier gas comprised of hydrogen gas and a diluting gas, mixed in a nonexplosive concentration. Sample air and carrier gas are drawn into and mixed in a manifold. A regulator meters the carrier gas flow to the manifold. The air sample/carrier gas mixture is pulled through a first moisture trap which adsorbs water from the air sample. The moisture then passes through a combustion chamber where hydrogen gas in the form of H/sub 2/ or HT is combusted into water. The manufactured water is transported by the air stream to a second moisture trap where it is adsorbed. The air is then discharged back into the atmosphere by means of a pump.

  20. Hydrogen carriers

    NASA Astrophysics Data System (ADS)

    He, Teng; Pachfule, Pradip; Wu, Hui; Xu, Qiang; Chen, Ping

    2016-12-01

    Hydrogen has the potential to be a major energy vector in a renewable and sustainable future energy mix. The efficient production, storage and delivery of hydrogen are key technical issues that require improvement before its potential can be realized. In this Review, we focus on recent advances in materials development for on-board hydrogen storage. We highlight the strategic design and optimization of hydrides of light-weight elements (for example, boron, nitrogen and carbon) and physisorbents (for example, metal-organic and covalent organic frameworks). Furthermore, hydrogen carriers (for example, NH3, CH3OH-H2O and cycloalkanes) for large-scale distribution and for on-site hydrogen generation are discussed with an emphasis on dehydrogenation catalysts.

  1. Synthesis of hydrogen-carbon clathrate material and hydrogen evolution therefrom at moderate temperatures and pressures

    DOEpatents

    Lueking, Angela [State College, PA; Narayanan, Deepa [Redmond, WA

    2011-03-08

    A process for making a hydrogenated carbon material is provided which includes forming a mixture of a carbon source, particularly a carbonaceous material, and a hydrogen source. The mixture is reacted under reaction conditions such that hydrogen is generated and/or released from the hydrogen source, an amorphous diamond-like carbon is formed, and at least a portion of the generated and/or released hydrogen associates with the amorphous diamond-like carbon, thereby forming a hydrogenated carbon material. A hydrogenated carbon material including a hydrogen carbon clathrate is characterized by evolution of molecular hydrogen at room temperature at atmospheric pressure in particular embodiments of methods and compositions according to the present invention.

  2. Metallic Hydrogen

    NASA Astrophysics Data System (ADS)

    Silvera, Isaac F.; Dias, Ranga; Noked, Ori; Salamat, Ashkan; Zaghoo, Mohamed

    2017-04-01

    One of the great challenges in condensed matter physics has been to produce metallic hydrogen (MH) in the laboratory. There are two approaches: solid molecular hydrogen can be compressed to high density at extreme pressures of order 5-6 megabars. The transition to MH should take place at low temperatures and is expected to occur as a structural first-order phase transition with dissociation of molecules into atoms, rather than the closing of a gap. A second approach is to produce dense molecular hydrogen at pressures of order 1-2 megabars and heat the sample. With increasing temperature, it was predicted that molecular hydrogen first melts and then dissociates to atomic metallic liquid hydrogen as a first-order phase transition. We have observed this liquid-liquid phase transition to metallic hydrogen, also called the plasma phase transition. In low-temperature studies, we have pressurized HD to over 3 megabars and observed two new phases. Molecular hydrogen has been pressurized to 4.2 megabars. A new phase transition has been observed at 3.55 megabars, but it is not yet metallic.

  3. Synthesis of Ni/Graphene Nanocomposite for Hydrogen Storage.

    PubMed

    Zhou, Chunyu; Szpunar, Jerzy A; Cui, Xiaoyu

    2016-06-22

    We have designed a Ni-graphene composite for hydrogen storage with Ni nanoparticles of 10 nm in size, uniformly dispersed over a graphene substrate. This system exhibits attractive features like high gravimetric density, ambient conditions, and low activation temperature for hydrogen release. When charged at room temperature and an atmospheric hydrogen pressure of 1 bar, it could yield a hydrogen capacity of 0.14 wt %. When hydrogen pressure increased to 60 bar, the sorbent had a hydrogen gravimetric density of 1.18 wt %. The hydrogen release could occur at an operating temperature below 150 °C and completes at 250 °C.

  4. Influence of high pressure hydrogen environment on creep deformation of Mo-Re, Haynes 188, and NARloy-Z alloys

    NASA Technical Reports Server (NTRS)

    Sastry, S. M. L.; Yang, Charles C.; Ouyang, Shewang; Jerina, K. L.; Schwartz, D. S.

    1994-01-01

    The present study focuses on the investigation of the influence of hydrogen on the mechanical properties of three types of alloys at elevated temperatures. The reasons for the consideration of hydrogen effects are the potential use of hydrogen as a coolant in gas-cooled reactors and fuel in advanced hypersonic vehicles. The materials used in hydrogen atmosphere must not be embrittled by hydrogen at ambient temperature and should have good strength in hydrogen atmosphere at elevated temperature. The paucity of information concerning the mechanical performance in hydrogen atmosphere at elevated temperature has been a limiting factor in the selection and design of structural components for operation in hydrogen environment.

  5. A Volcanic Hydrogen Habitable Zone

    NASA Astrophysics Data System (ADS)

    Ramirez, Ramses M.; Kaltenegger, Lisa

    2017-03-01

    The classical habitable zone (HZ) is the circular region around a star in which liquid water could exist on the surface of a rocky planet. The outer edge of the traditional N2–CO2–H2O HZ extends out to nearly ∼1.7 au in our solar system, beyond which condensation and scattering by CO2 outstrips its greenhouse capacity. Here, we show that volcanic outgassing of atmospheric H2 can extend the outer edge of the HZ to ∼2.4 au in our solar system. This wider volcanic-hydrogen HZ (N2–CO2–H2O–H2) can be sustained as long as volcanic H2 output offsets its escape from the top of the atmosphere. We use a single-column radiative-convective climate model to compute the HZ limits of this volcanic hydrogen HZ for hydrogen concentrations between 1% and 50%, assuming diffusion-limited atmospheric escape. At a hydrogen concentration of 50%, the effective stellar flux required to support the outer edge decreases by ∼35%–60% for M–A stars. The corresponding orbital distances increase by ∼30%–60%. The inner edge of this HZ only moves out ∼0.1%–4% relative to the classical HZ because H2 warming is reduced in dense H2O atmospheres. The atmospheric scale heights of such volcanic H2 atmospheres near the outer edge of the HZ also increase, facilitating remote detection of atmospheric signatures.

  6. Polymer formulations for gettering hydrogen

    DOEpatents

    Shepodd, Timothy J.; Even, Jr., William R.

    2000-01-01

    A novel method for preparing a hydrogenation composition comprising organic polymer molecules having carbon--carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces and particularly from atmospheres within enclosed spaces that contain air, water vapor, oxygen, carbon dioxide or ammonia. The organic polymers molecules containing carbon--carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble noble metal catalyst composition. High molecular weight polymers may be added to the organic polymer/catalyst mixture in order to improve their high temperature performance. The hydrogenation composition is prepared by dispersing the polymers in a suitable solvent, forming thereby a solution suspension, flash-freezing droplets of the solution in a liquid cryogen, freeze-drying the frozen droplets to remove frozen solvent incorporated in the droplets, and recovering the dried powder thus formed.

  7. Chemochromic Hydrogen Sensors

    NASA Technical Reports Server (NTRS)

    Wiggins, Bryan C.

    2007-01-01

    As fossil fuel supplies decline, hydrogen is quickly becoming an increasingly important fuel source. Currently hydrogen is the prime fuel of today's space vehicles (e.g., Space Shuttle) and featured as a fuel for some prototype vehicles such as the BMW seven series model. Hydrogen is a colorless, odorless gas with a 4% lower explosive limit which makes leak detection a priority. In an effort to support the use of hydrogen, a chemochromic (color changing) sensor was developed that is robust, simple to use, and does not require active operation. It can be made into a thin tape which can be conveniently used for leak detection at flanges, valves, or outlets. Chemochromic sensors can be either reversible or irreversible; however, irreversible chemochromic sensors will be analyzed in this report. The irreversible sensor is useful during hazardous operations when personnel cannot be present. To actively monitor leaks, testing of the irreversible sensor against environmental effects was completed and results indicated this material is suitable for outdoor use in the harsh beachside environment of Kennedy Space Center. The experiments in this report will give additional results to the environmental testing by adding solid rocket booster residue as a variable. The primary motivation for these experiments is to prepare the sensors for the launch pad environment at the Kennedy Space Center. In an effort to simulate the atmosphere at the pads before and after launch, the chemochromic sensors are exposed to solid rocket residue under various conditions.

  8. Improved retort for cleaning metal powders with hydrogen

    NASA Technical Reports Server (NTRS)

    Arias, A.

    1969-01-01

    Improved cleaning retort produces uniform temperature distribution in the heated zone and minimizes hydrogen channeling through the powder bed. Retort can be used for nonmetallic powders, sintering in a reducing atmosphere, and for cleaning powders in reduction atmospheres other than hydrogen.

  9. Modeling leaks from liquid hydrogen storage systems.

    SciTech Connect

    Winters, William Stanley, Jr.

    2009-01-01

    This report documents a series of models for describing intended and unintended discharges from liquid hydrogen storage systems. Typically these systems store hydrogen in the saturated state at approximately five to ten atmospheres. Some of models discussed here are equilibrium-based models that make use of the NIST thermodynamic models to specify the states of multiphase hydrogen and air-hydrogen mixtures. Two types of discharges are considered: slow leaks where hydrogen enters the ambient at atmospheric pressure and fast leaks where the hydrogen flow is usually choked and expands into the ambient through an underexpanded jet. In order to avoid the complexities of supersonic flow, a single Mach disk model is proposed for fast leaks that are choked. The velocity and state of hydrogen downstream of the Mach disk leads to a more tractable subsonic boundary condition. However, the hydrogen temperature exiting all leaks (fast or slow, from saturated liquid or saturated vapor) is approximately 20.4 K. At these temperatures, any entrained air would likely condense or even freeze leading to an air-hydrogen mixture that cannot be characterized by the REFPROP subroutines. For this reason a plug flow entrainment model is proposed to treat a short zone of initial entrainment and heating. The model predicts the quantity of entrained air required to bring the air-hydrogen mixture to a temperature of approximately 65 K at one atmosphere. At this temperature the mixture can be treated as a mixture of ideal gases and is much more amenable to modeling with Gaussian entrainment models and CFD codes. A Gaussian entrainment model is formulated to predict the trajectory and properties of a cold hydrogen jet leaking into ambient air. The model shows that similarity between two jets depends on the densimetric Froude number, density ratio and initial hydrogen concentration.

  10. Hydroperoxides as Hydrogen Bond Donors

    NASA Astrophysics Data System (ADS)

    Møller, Kristian H.; Tram, Camilla M.; Hansen, Anne S.; Kjaergaard, Henrik G.

    2016-06-01

    Hydroperoxides are formed in the atmosphere following autooxidation of a wide variety of volatile organics emitted from both natural and anthropogenic sources. This raises the question of whether they can form hydrogen bonds that facilitate aerosol formation and growth. Using a combination of Fourier transform infrared spectroscopy, FT-IR, and ab initio calculations, we have compared the gas phase hydrogen bonding ability of tert-butylhydroperoxide (tBuOOH) to that of tert-butanol (tBuOH) for a series of bimolecular complexes with different acceptors. The hydrogen bond acceptor atoms studied are nitrogen, oxygen, phosphorus and sulphur. Both in terms of calculated redshifts and binding energies (BE), our results suggest that hydroperoxides are better hydrogen bond donors than the corresponding alcohols. In terms of hydrogen bond acceptor ability, we find that nitrogen is a significantly better acceptor than the other three atoms, which are of similar strength. We observe a similar trend in hydrogen bond acceptor ability with other hydrogen bond donors including methanol and dimethylamine.

  11. Storing Hydrogen

    SciTech Connect

    Kim, Hyun Jeong; Karkamkar, Abhijeet J.; Autrey, Thomas; Chupas, Peter; Proffen, Thomas E.

    2010-05-31

    Researchers have been studying mesoporous materials for almost two decades with a view to using them as hosts for small molecules and scaffolds for molding organic compounds into new hybrid materials and nanoparticles. Their use as potential storage systems for large quantities of hydrogen has also been mooted. Such systems that might hold large quantities of hydrogen safely and in a very compact volume would have enormous potential for powering fuel cell vehicles, for instance. A sponge-like form of silicon dioxide, the stuff of sand particles and computer chips, can soak up and store other compounds including hydrogen. Studies carried out at the XOR/BESSRC 11-ID-B beamline at the APS have revealed that the nanoscopic properties of the hydrogenrich compound ammonia borane help it store hydrogen more efficiently than usual. The material may have potential for addressing the storage issues associated with a future hydrogen economy. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  12. Hydrogen sulfide pollution in wastewater treatment facilities

    SciTech Connect

    AlDhowalia, K.H. )

    1987-01-01

    The hydrogen sulfide (H{sub 2}S) found in wastewater collection systems and wastewater treatment facilities results from the bacterial reduction of the sulfate ion (SO{sub 4}). Hydrogen sulfide is a gas that occurs both in the sewer atmosphere and as a dissolved gas in the wastewater. When raw wastewater first enters the wastewater treatment facility by gravity most of the hydrogen sulfide is in the gaseous phase and will escape into the atmosphere at the inlet structures. Also some of the dissolved hydrogen sulfide will be released at points of turbulance such as at drops in flow, flumes, or aeration chambers. Several factors can cause excessive hydrogen sulfide concentrations in a sewerage system. These include septic sewage, long flow times in the sewerage system, high temperatures, flat sewer grades, and poor ventilation. These factors are discussed in this paper.

  13. Photovoltaic hydrogen production

    SciTech Connect

    Hiser, H.W.; Memory, S.B.; Veziroglu, T.N.; Padin, J.

    1996-10-01

    This is a new project, which started in June 1995, and involves photovoltaic hydrogen production as a fuel production method for the future. In order to increase the hydrogen yield, it was decided to use hybrid solar collectors to generate D.C. electricity, as well as high temperature steam for input to the electrolyzer. In this way, some of the energy needed to dissociate the water is supplied in the form of heat (or low grade energy), to generate steam, which results in a reduction of electrical energy (or high grade energy) needed. As a result, solar to hydrogen conversion efficiency is increased. In the above stated system, the collector location, the collector tracking sub-system (i.e., orientation/rotation), and the steam temperature have been taken as variables. Five locations selected - in order to consider a variety of latitudes, altitudes, cloud coverage and atmospheric conditions - are Atlanta, Denver, Miami, Phoenix and Salt Lake City. Plain PV and hybrid solar collectors for a stationary south facing system and five different collector rotation systems have been analyzed. Steam temperatures have been varied between 200{degrees}C and 1200{degrees}C. During the first year, solar to hydrogen conversion efficiencies have been considered. The results show that higher steam temperatures, 2 dimensional tracking system, higher elevations and dryer climates causes higher conversion efficiencies. Cost effectiveness of the sub-systems and of the overall system will be analyzed during the second year. Also, initial studies will be made of an advanced high efficiency hybrid solar hydrogen production system.

  14. Method of producing hydrogenated amorphous silicon film

    DOEpatents

    Wiesmann, Harold J.

    1980-01-01

    This invention relates to hydrogenated amorphous silicon produced by thermally decomposing silane (SiH.sub.4) or other gases comprising H and Si, from a tungsten or carbon foil heated to a temperature of about 1400.degree.-1600.degree. C., in a vacuum of about 10.sup.-6 to 19.sup.-4 torr, to form a gaseous mixture of atomic hydrogen and atomic silicon, and depositing said gaseos mixture onto a substrate independent of and outside said source of thermal decomposition, to form hydrogenated amorphous silicon. The presence of an ammonia atmosphere in the vacuum chamber enhances the photoconductivity of the hydrogenated amorphous silicon film.

  15. Hydrogen separation membrane on a porous substrate

    DOEpatents

    Song, Sun-Ju; Lee, Tae H.; Chen, Ling; Dorris, Stephen E.; Balachandran, Uthamalingam

    2011-06-14

    A hydrogen permeable membrane is disclosed. The membrane is prepared by forming a mixture of metal oxide powder and ceramic oxide powder and a pore former into an article. The article is dried at elevated temperatures and then sintered in a reducing atmosphere to provide a dense hydrogen permeable portion near the surface of the sintered mixture. The dense hydrogen permeable portion has a higher initial concentration of metal than the remainder of the sintered mixture and is present in the range of from about 20 to about 80 percent by volume of the dense hydrogen permeable portion.

  16. Planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Ingersoll, A. P.; Dobrovolskis, A. R.; Jakosky, B. M.

    1979-01-01

    The present paper deals with some of the principal data on extraterrestrial atmospheres obtained during the period 1975-1978. The atmospheres of Venus, Mars, Jupiter, and the Jovian satellites are examined, showing that many first-order questions concerning composition, physical state, and kinematics of these atmospheres have been answered.

  17. Hydrogen program overview

    SciTech Connect

    Gronich, S.

    1997-12-31

    This paper consists of viewgraphs which summarize the following: Hydrogen program structure; Goals for hydrogen production research; Goals for hydrogen storage and utilization research; Technology validation; DOE technology validation activities supporting hydrogen pathways; Near-term opportunities for hydrogen; Market for hydrogen; and List of solicitation awards. It is concluded that a full transition toward a hydrogen economy can begin in the next decade.

  18. Hydrogen gas purification apparatus

    SciTech Connect

    Yanagihara, N.; Gamo, T.; Iwaki, T.; Moriwaki, Y.

    1984-04-24

    A hydrogen gas purification apparatus which includes at least one set of two hydrogen purification containers coupled to each other for heat exchanging therebetween, each of the hydrogen purification containers containing a hydrogen absorbing alloy. The hydrogen gas purification apparatus is so arranged as to cause hydrogen gas to be selectively desorbed from and absorbed into the hydrogen absorbing alloy by the amount of heat produced when the hydrogen gas is selectively absorbed into and desorbed from the hydrogen absorbing alloy.

  19. Carbon and hydrogen isotope composition and C-14 concentration in methane from sources and from the atmosphere: Implications for a global methane budget. Final report, 1 January-30 June 1991

    SciTech Connect

    Wahlen, M.

    1994-03-01

    The topics covered include the following: biogenic methane studies; forest soil methane uptake; rice field methane sources; atmospheric measurements; stratospheric samples; Antarctica; California; and Germany.

  20. The Summer of Hydrogen

    NASA Technical Reports Server (NTRS)

    Weber, Philip

    2008-01-01

    Ground crew veterans at Kennedy Space Center still talk about what they call "the summer of hydrogen"-the long, frustrating months in 1990 when the shuttle fleet was grounded by an elusive hydrogen leak that foiled our efforts to fill the orbiter's external fuel tank. Columbia (STS-35) was on Launch Pad A for a scheduled May 30 launch when we discovered the hydrogen leak during - tanking. The external fuel tank is loaded through the orbiter. Liquid hydrogen flows through a 17-inch umbilical between the orbiter and the tank. During fueling, we purge the aft fuselage with gaseous nitrogen to reduce the risk of fire, and we have a leak-detection system in the mobile launch platform, which samples (via tygon tubing) the atmosphere in and around the vehicle, drawing it down to a mass spectrometer that analyzes its composition. When we progressed to the stage of tanking where liquid hydrogen flows through the vehicle, the concentration of hydrogen approached four percent-the limit above which it would be dangerously flammable. We had a leak. We did everything we could think of to find it, and the contractor who supplied the flight hardware was there every day, working alongside us. We did tanking tests, which involved instrumenting the suspected leak sources, and cryo-loaded the external tank to try to isolate precisely where the leak originated. We switched out umbilicals; we replaced the seals between the umbilical and the orbiter. We inspected the seals microscopically and found no flaws. We replaced the recirculation pumps, and we found and replaced a damaged teflon seal in a main propulsion system detent cover, which holds the prevalve-the main valve supplying hydrogen to Space Shuttle Main Engine 3 -in the open position. The seal passed leak tests at ambient temperature but leaked when cryogenic temperatures were applied. We added new leak sensors-up to twenty at a time and tried to be methodical in our placements to narrow down the possible sources of the problem

  1. Survey of Hydrogen Combustion Properties

    NASA Technical Reports Server (NTRS)

    Drell, Isadore L; Belles, Frank E

    1958-01-01

    This literature digest of hydrogen-air combustion fundamentals presents data on flame temperature, burning velocity, quenching distance, flammability limits, ignition energy, flame stability, detonation, spontaneous ignition, and explosion limits. The data are assessed, recommended values are given, and relations among various combustion properties are discussed. New material presented includes: theoretical treatment of variation in spontaneous ignition lag with temperature, pressure, and composition, based on reaction kinetics of hydrogen-air composition range for 0.01 to 100 atmospheres and initial temperatures of 0 degrees to 1400 degrees k.

  2. Hydrogen chloride

    Integrated Risk Information System (IRIS)

    Hydrogen chloride ; CASRN 7647 - 01 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogeni

  3. Hydrogen sulfide

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 03 / 005 www.epa.gov / iris TOXICOLOGICAL REVIEW OF HYDROGEN SULFIDE ( CAS No . 7783 - 06 - 4 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) June 2003 U.S . Environmental Protection Agency Washington , DC DISCLAIMER This document has been revie

  4. Hydrogen technologies

    SciTech Connect

    Not Available

    1992-05-01

    To the non-nonsense engineer, any talk of a hydrogen economy may seem like so much hot air. This paper reports that as legislative, safety and environmental issues continue to tighten, they're promoting hydrogen's chances as an energy source and, more immediately, its prospects as a chemical feedstock. Paradoxically, the environmental demands that are stimulating hydrogen demand are also inhibiting the gas's production. Previously, gasoline was made with benzene, which means that H{sub 2} was rejected. But now that the laws mandate lower aromatic and higher oxygenate levels in gasolines, there's less H{sub 2} available as byproduct. At the same time, H{sub 2} demand is rising in hydrodesulfurization units, since the same laws require refiners to cut sulfur levels in fuels. Supplementary sources for the gas are also shrinking. In the chlor-alkali industry, H{sub 2} output is dropping, as demand for its coproduct chlorine weakens. At the same time, H{sub 2} demand for the making of hydrogen peroxide is growing, as that environmentally safer bleach gains chlorine's market share.

  5. Metallic Hydrogen

    NASA Astrophysics Data System (ADS)

    Silvera, Isaac; Zaghoo, Mohamed; Salamat, Ashkan

    2015-03-01

    Hydrogen is the simplest and most abundant element in the Universe. At high pressure it is predicted to transform to a metal with remarkable properties: room temperature superconductivity, a metastable metal at ambient conditions, and a revolutionary rocket propellant. Both theory and experiment have been challenged for almost 80 years to determine its condensed matter phase diagram, in particular the insulator-metal transition. Hydrogen is predicted to dissociate to a liquid atomic metal at multi-megabar pressures and T =0 K, or at megabar pressures and very high temperatures. Thus, its predicted phase diagram has a broad field of liquid metallic hydrogen at high pressure, with temperatures ranging from thousands of degrees to zero Kelvin. In a bench top experiment using static compression in a diamond anvil cell and pulsed laser heating, we have conducted measurements on dense hydrogen in the region of 1.1-1.7 Mbar and up to 2200 K. We observe a first-order phase transition in the liquid phase, as well as sharp changes in optical transmission and reflectivity when this phase is entered. The optical signature is that of a metal. The mapping of the phase line of this transition is in excellent agreement with recent theoretical predictions for the long-sought plasma phase transition to metallic hydrogen. Research supported by the NSF, Grant DMR-1308641, the DOE Stockpile Stewardship Academic Alliance Program, Grant DE-FG52-10NA29656, and NASA Earth and Space Science Fellowship Program, Award NNX14AP17H.

  6. Cryogenic hydrogen-induced air liquefaction technologies

    NASA Technical Reports Server (NTRS)

    Escher, William J. D.

    1990-01-01

    Extensively utilizing a special advanced airbreathing propulsion archives database, as well as direct contacts with individuals who were active in the field in previous years, a technical assessment of cryogenic hydrogen-induced air liquefaction, as a prospective onboard aerospace vehicle process, was performed and documented. The resulting assessment report is summarized. Technical findings are presented relating the status of air liquefaction technology, both as a singular technical area, and also that of a cluster of collateral technical areas including: compact lightweight cryogenic heat exchangers; heat exchanger atmospheric constituents fouling alleviation; para/ortho hydrogen shift conversion catalysts; hydrogen turbine expanders, cryogenic air compressors and liquid air pumps; hydrogen recycling using slush hydrogen as heat sink; liquid hydrogen/liquid air rocket-type combustion devices; air collection and enrichment systems (ACES); and technically related engine concepts.

  7. Hydrogen peroxide poisoning

    MedlinePlus

    Hydrogen peroxide is used in these products: Hydrogen peroxide Hair bleach Some contact lens cleaners Note: Household hydrogen peroxide has a 3% concentration. That means it contains 97% water and 3% hydrogen peroxide. Hair ...

  8. Hydrogen forming reaction process

    SciTech Connect

    Marianowski, L.G.; Fleming, D.K.

    1989-03-07

    A hydrogen forming process is described, comprising: conducting in a hydrogen production zone a chemical reaction forming mixed gases comprising molecular hydrogen; contacting one side of a hydrogen ion porous and molecular gas nonporous metallic foil with the mixed gases in the hydrogen production zone; dissociating the molecular hydrogen to ionic hydrogen on the one side of the metallic foil; passing the ionic hydrogen through the metallic foil to its other side; and withdrawing hydrogen from the other side of the metallic foil, thereby removing hydrogen from the hydrogen production zone.

  9. Atmospheric neutrons

    NASA Technical Reports Server (NTRS)

    Korff, S. A.; Mendell, R. B.; Merker, M.; Light, E. S.; Verschell, H. J.; Sandie, W. S.

    1979-01-01

    Contributions to fast neutron measurements in the atmosphere are outlined. The results of a calculation to determine the production, distribution and final disappearance of atmospheric neutrons over the entire spectrum are presented. An attempt is made to answer questions that relate to processes such as neutron escape from the atmosphere and C-14 production. In addition, since variations of secondary neutrons can be related to variations in the primary radiation, comment on the modulation of both radiation components is made.

  10. White dwarf stars with chemically stratified atmospheres

    NASA Technical Reports Server (NTRS)

    Muchmore, D.

    1982-01-01

    Recent observations and theory suggest that some white dwarfs may have chemically stratified atmospheres - thin layers of hydrogen lying above helium-rich envelopes. Models of such atmospheres show that a discontinuous temperature inversion can occur at the boundary between the layers. Model spectra for layered atmospheres at 30,000 K and 50,000 K tend to have smaller decrements at 912 A, 504 A, and 228 A than uniform atmospheres would have. On the basis of their continuous extreme ultraviolet spectra, it is possible to distinguish observationally between uniform and layered atmospheres for hot white dwarfs.

  11. Planets and their atmospheres - Origin and evolution

    NASA Astrophysics Data System (ADS)

    Lewis, J. S.; Prinn, R. G.

    The origin, evolution, and composition of the planetary atmospheres are examined in an introductory review of ground-based and in situ observations and theoretical models. Chapters are devoted to the retention of volatiles by planets; evolutionary processes (such as hydrogen loss, accretion and outgassing, dissolution, photo-condensation, reactions with planetary surfaces, biochemical transformations, and atmospheric escape); and the present characteristics of the planetary, lunar-size-object, and asteroid atmospheres. Graphs, diagrams, and tables of numerical data are provided.

  12. Hydrogen scavengers

    DOEpatents

    Carroll, David W.; Salazar, Kenneth V.; Trkula, Mitchell; Sandoval, Cynthia W.

    2002-01-01

    There has been invented a codeposition process for fabricating hydrogen scavengers. First, a .pi.-bonded allylic organometallic complex is prepared by reacting an allylic transition metal halide with an organic ligand complexed with an alkali metal; and then, in a second step, a vapor of the .pi.-bonded allylic organometallic complex is combined with the vapor of an acetylenic compound, irradiated with UV light, and codeposited on a substrate.

  13. Atmospheric escape, redox evolution, and planetary habitability

    NASA Astrophysics Data System (ADS)

    Catling, D. C.; Zahnle, K. J.

    2011-12-01

    net escape of hydrogen relative to heavier oxygen is the generally accepted explanation for the present oxidation state: Venus and Mars amongst the planets, and Ganymede, Europa, and Rhea amongst bodies with extremely tenuous atmospheres. We also argue that hydrogen escape was the key factor for oxidizing the Earth and facilitating the increase of photosynthetically-produced oxygen in the Proterozoic atmosphere. Our view about the primacy of hydrogen escape with regard to the Earth's atmospheric oxygenation is perhaps less widely accepted. However, it was inevitable that hydrogen escaped from Earth's early anoxic atmosphere at a significant rate. The result was a very big integrated oxidation consistent with what is observed in the Earth's crust in addition to some export to the mantle. In conclusion, a better understanding of atmospheric escape processes appears critical for understanding the suitability of planets for harboring life from simple to advanced forms.

  14. Atmospheric chemistry

    SciTech Connect

    Sloane, C.S. ); Tesche, T.W. )

    1991-01-01

    This book covers the predictive strength of atmospheric models. The book covers all of the major important atmospheric areas, including large scale models for ozone depletion and global warming, regional scale models for urban smog (ozone and visibility impairment) and acid rain, as well as accompanying models of cloud processes and biofeedbacks.

  15. Lunar atmospheric composition experiment

    NASA Technical Reports Server (NTRS)

    Hoffman, J. H.

    1975-01-01

    Apollo 17 carried a miniature mass spectrometer, called the Lunar Atmospheric Composition Experiment (LACE), to the moon as part of the Apollo Lunar Surface Experiments Package (ALSEP) to study the composition and variations in the lunar atmosphere. The instrument was successfully deployed in the Taurus-Littrow Valley with its entrance aperture oriented upward to intercept and measure the downward flux of gases at the lunar surface. During the ten lunations that the LACE operated, it produced a large base of data on the lunar atmosphere, mainly collected at night time. It was found that thermal escape is the most rapid loss mechanism for hydrogen and helium. For heavier gases, photoionization followed by acceleration through the solar wind electric field accounted for most of the loss. The dominant gases on the moosn were argon and helium, and models formed for their distribution are described in detail. It is concluded that most of the helium in the lunar atmosphere is of solar wind origin, and that there also exist very small amounts of methane, ammonia, and carbon dioxide.

  16. Hydrogen environment embrittlement

    NASA Technical Reports Server (NTRS)

    Gray, H. R.

    1972-01-01

    Hydrogen embrittlement is classified into three types: internal reversible hydrogen embrittlement, hydrogen reaction embrittlement, and hydrogen environment embrittlement. Characteristics of and materials embrittled by these types of hydrogen embrittlement are discussed. Hydrogen environment embrittlement is reviewed in detail. Factors involved in standardizing test methods for detecting the occurrence of and evaluating the severity of hydrogen environment embrittlement are considered. The effect of test technique, hydrogen pressure, purity, strain rate, stress concentration factor, and test temperature are discussed. Additional research is required to determine whether hydrogen environment embrittlement and internal reversible hydrogen embrittlement are similar or distinct types of embrittlement.

  17. Fast Quenching For Hydrogen-Embrittlement Tests

    NASA Technical Reports Server (NTRS)

    Petri, Mark J.; Burkhart, Richard L.; Koncel, Joseph F.

    1990-01-01

    Apparatus exposes hot metal specimens in hydrogen atmospheres to sudden cooling. Heater surrounds pressure vessel initially. On command, heater slides downward on track, exposing vessel. Spray bar falls over vessel and directs high-pressure jets of cold water at it. Developed to evaluate susceptibilities of specimens to embrittlement by hydrogen. Cools specimens by 1,050 degrees F (580 degrees C) in 160 seconds.

  18. A Micro Hydrogen Air Fuel Cell

    DTIC Science & Technology

    2005-10-01

    thin enough that it does not block the channels. This eliminated the step of having to sputter chrome /gold onto the wells and channels. Currently...to make the ink compatible with conventional thick film printing. In addition, the typical process for manufacturing electrode/membrane assemblies...catalytic activity of these inks, polarization curves for hydrogen oxidation were obtained using a pure hydrogen feed at one atmosphere pressure. With

  19. Ultraviolet absorption cross sections of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Lin, C. L.; Rohatgi, N. K.; Demore, W. B.

    1978-01-01

    Absorption cross-sections of hydrogen peroxide vapor and of neutral aqueous solutions of hydrogen peroxide were measured in the wavelength range from 195 to 350 nm at 296 K. The spectrophotometric procedure is described, and the reported cross-sections are compared with values obtained by other researchers. Photodissociation coefficients of atmospheric H2O2 were calculated for direct absorption of unscattered solar radiation, and the vertical distributions of these coefficients are shown for various solar zenith angles.

  20. Hydrogen detector

    DOEpatents

    Kanegae, Naomichi; Ikemoto, Ichiro

    1980-01-01

    A hydrogen detector of the type in which the interior of the detector is partitioned by a metal membrane into a fluid section and a vacuum section. Two units of the metal membrane are provided and vacuum pipes are provided independently in connection to the respective units of the metal membrane. One of the vacuum pipes is connected to a vacuum gauge for static equilibrium operation while the other vacuum pipe is connected to an ion pump or a set of an ion pump and a vacuum gauge both designed for dynamic equilibrium operation.

  1. Hydrogen: the future energy carrier.

    PubMed

    Züttel, Andreas; Remhof, Arndt; Borgschulte, Andreas; Friedrichs, Oliver

    2010-07-28

    Since the beginning of the twenty-first century the limitations of the fossil age with regard to the continuing growth of energy demand, the peaking mining rate of oil, the growing impact of CO2 emissions on the environment and the dependency of the economy in the industrialized world on the availability of fossil fuels became very obvious. A major change in the energy economy from fossil energy carriers to renewable energy fluxes is necessary. The main challenge is to efficiently convert renewable energy into electricity and the storage of electricity or the production of a synthetic fuel. Hydrogen is produced from water by electricity through an electrolyser. The storage of hydrogen in its molecular or atomic form is a materials challenge. Some hydrides are known to exhibit a hydrogen density comparable to oil; however, these hydrides require a sophisticated storage system. The system energy density is significantly smaller than the energy density of fossil fuels. An interesting alternative to the direct storage of hydrogen are synthetic hydrocarbons produced from hydrogen and CO2 extracted from the atmosphere. They are CO2 neutral and stored like fossil fuels. Conventional combustion engines and turbines can be used in order to convert the stored energy into work and heat.

  2. Atmospheric composition

    NASA Technical Reports Server (NTRS)

    Daniels, G. E.

    1973-01-01

    The earth's atmosphere is made up of a number of gases in different relative amounts. Near sea level and up to about 90 km, the amount of these atmospheric gases in clean, relatively dry air is practically constant. Four of these gases, nitrogen, oxygen, argon, and carbon dioxide, make up 99.99 percent by volume of the atmosphere. Two gases, ozone and water vapor, change in relative amounts, but the total amount of these two is very small compared to the amount of the other gases. The atmospheric composition shown in a table can be considered valid up to 90 km geometric altitude. Above 90 km, mainly because of molecular dissociation and diffusive separation, the composition changes.

  3. Atmospheric pollution

    SciTech Connect

    Pickett, E.E.

    1987-01-01

    Atmospheric pollution (AP), its causes, and measures to prevent or reduce it are examined in reviews and reports presented at a workshop held in Damascus, Syria in August 1985. Topics discussed include AP and planning studies, emission sources, pollutant formation and transformation, AP effects on man and vegetation, AP control, atmospheric dispersion mechanisms and modeling, sampling and analysis techniques, air-quality monitoring, and applications. Diagrams, graphs, and tables of numerical data are provided.

  4. Process for recovering evolved hydrogen enriched with at least one heavy hydrogen isotope

    DOEpatents

    Tanaka, John; Reilly, Jr., James J.

    1978-01-01

    This invention relates to a separation means and method for enriching a hydrogen atmosphere with at least one heavy hydrogen isotope by using a solid titaniun alloy hydride. To this end, the titanium alloy hydride containing at least one metal selected from the group consisting of vanadium, chromium, manganese, molybdenum, iron, cobalt and nickel is contacted with a circulating gaseous flow of hydrogen containing at least one heavy hydrogen isotope at a temperature in the range of -20.degree. to +40.degree. C and at a pressure above the dissociation pressure of the hydrided alloy selectively to concentrate at least one of the isotopes of hydrogen in the hydrided metal alloy. The contacting is continued until equilibrium is reached, and then the gaseous flow is isolated while the temperature and pressure of the enriched hydride remain undisturbed selectively to isolate the hydride. Thereafter, the enriched hydrogen is selectively recovered in accordance with the separation factor (S.F.) of the alloy hydride employed.

  5. Transportation Fuels and the Hydrogen Economy

    NASA Astrophysics Data System (ADS)

    Gabbard, Alex

    2004-11-01

    An energy analysis of transportation fuels is performed for comparing automobiles and fuels currently in the marketplace as real world benchmarks projected as "hydrogen economy" requirements. Comparisons are made for ideal case average energy values at Standard Temperature and Pressure (STP) at 20°C, 1 atmosphere with no loses. "Real world" benchmarks currently in the marketplace illuminate the challenges to be met if an equivalent "hydrogen economy" is to become reality. The idea of a "hydrogen economy" is that, at some time in the future, world energy needs will be supplied in part or totally from hydrogen; in part as compared to the current "petroleum economy" that is the source of most of the world's transportation fuels and only a portion of total energy use, or hydrogen as the source of all energy consumption.

  6. Hydrogen in the Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Walter, S.; Kock, A.; Steinhoff, T.; Röckmann, T.

    2009-04-01

    Although hydrogen (H2) is considered as one of the most important future energy carriers, little is known about the global biogeochemical cycle of this trace gas (Rhee et al. 2006). In order to assess the potential impact of expected increasing H2 concentrations to the atmosphere a fundamental understanding of the global H2 cycle is indispensable (Tromp et al. 2003, Warwick et al. 2004). Oceans are one source of atmospheric H2, produced by biological processes such as fermentation and N2-fixation and abiotic photochemical processes (Punshon and Moore 2008 and references herein). Further information can be obtained by studying the isotope composition of H2. However, the isotopic ratio of oceanic released H2 is unknown and has so far only been estimated from thermodynamic equilibrium. We investigated the atmospheric D/H isotopic ratio of H2 in the Atlantic Ocean. First results of atmospheric H2 isotope ratios from the West African coast of Mauritania and from a meridional transect over the Atlantic Ocean will be presented. Samples were taken onboard the German research vessel "Poseidon" in February 2007 associated to SOPRAN and during the cruise Ant XXIV-4 with the German research vessel "Polarstern" in April 2008 between Punta Arenas (Chile) and Bremerhaven (Germany). Literature Punshon, S. and R.M. Moore; Aerobic hydrogen production and dinitrogen fixation in the marine cyanobacterium Trichodesmium erythraeum IMS101; Limnol. Oceanogr., 53(6), 2749-2753, 2008. Rhee, T.S., C.A.M. Brenninkmeijer, and T. Röckmann; The overwhelming role of soils in the global atmospheric hydrogen cycle, Atmos. Chem. Phys., 6, 1611-1625, 2006. Tromp, T.K., Shi, R.-L., Allen, M., Eiler, J.M., and Y. L. Yung1; Potential Environmental Impact of a Hydrogen Economy on the Stratosphere, Science, 300, 1740-1742, 2003. Warwick, N.J., Bekki, S., Nisbet, E.G., and J.A. Pyle; Impact of a hydrogen economy on the stratosphere and troposphere studied in a 2-D model; Geo.Res.Lett., 31, L05107, doi:10

  7. Mechanochemical hydrogenation of coal

    DOEpatents

    Yang, Ralph T.; Smol, Robert; Farber, Gerald; Naphtali, Leonard M.

    1981-01-01

    Hydrogenation of coal is improved through the use of a mechanical force to reduce the size of the particulate coal simultaneously with the introduction of gaseous hydrogen, or other hydrogen donor composition. Such hydrogen in the presence of elemental tin during this one-step size reduction-hydrogenation further improves the yield of the liquid hydrocarbon product.

  8. Hydrogen iodide decomposition

    DOEpatents

    O'Keefe, Dennis R.; Norman, John H.

    1983-01-01

    Liquid hydrogen iodide is decomposed to form hydrogen and iodine in the presence of water using a soluble catalyst. Decomposition is carried out at a temperature between about 350.degree. K. and about 525.degree. K. and at a corresponding pressure between about 25 and about 300 atmospheres in the presence of an aqueous solution which acts as a carrier for the homogeneous catalyst. Various halides of the platinum group metals, particularly Pd, Rh and Pt, are used, particularly the chlorides and iodides which exhibit good solubility. After separation of the H.sub.2, the stream from the decomposer is countercurrently extracted with nearly dry HI to remove I.sub.2. The wet phase contains most of the catalyst and is recycled directly to the decomposition step. The catalyst in the remaining almost dry HI-I.sub.2 phase is then extracted into a wet phase which is also recycled. The catalyst-free HI-I.sub.2 phase is finally distilled to separate the HI and I.sub.2. The HI is recycled to the reactor; the I.sub.2 is returned to a reactor operating in accordance with the Bunsen equation to create more HI.

  9. Process and catalyst for the hydrogenation of coal

    SciTech Connect

    Wernicke, H.J.; Zimmerman, H.

    1985-05-07

    Blast furnace flue dust is used as a catalyst in a process for the hydrogenation of coal. A flowable mixture of finely divided coal particles and liquid hydrocarbons is brought to high pressure and to reaction temperature. The mixture is hydrogenated with hydrogen in the presence of blast furnace dust as a hydrogenation catalyst. The cost-effective hydrogenation catalyst is reused profitably subsequent to application in the coal hydrogenation process. Gaseous products are separated from liquid and solid reaction products. Liquid products are vaporized and are fractionated under atmospheric pressure and under vacuum. Hydrogen for use in the hydrogenation is produced by partial oxidation of the residue, and the catalyst is deposited as slag, which is returned to the blast furnace.

  10. Solar flare model atmospheres

    NASA Technical Reports Server (NTRS)

    Hawley, Suzanne L.; Fisher, George H.

    1993-01-01

    Solar flare model atmospheres computed under the assumption of energetic equilibrium in the chromosphere are presented. The models use a static, one-dimensional plane parallel geometry and are designed within a physically self-consistent coronal loop. Assumed flare heating mechanisms include collisions from a flux of non-thermal electrons and x-ray heating of the chromosphere by the corona. The heating by energetic electrons accounts explicitly for variations of the ionized fraction with depth in the atmosphere. X-ray heating of the chromosphere by the corona incorporates a flare loop geometry by approximating distant portions of the loop with a series of point sources, while treating the loop leg closest to the chromospheric footpoint in the plane-parallel approximation. Coronal flare heating leads to increased heat conduction, chromospheric evaporation and subsequent changes in coronal pressure; these effects are included self-consistently in the models. Cooling in the chromosphere is computed in detail for the important optically thick HI, CaII and MgII transitions using the non-LTE prescription in the program MULTI. Hydrogen ionization rates from x-ray photo-ionization and collisional ionization by non-thermal electrons are included explicitly in the rate equations. The models are computed in the 'impulsive' and 'equilibrium' limits, and in a set of intermediate 'evolving' states. The impulsive atmospheres have the density distribution frozen in pre-flare configuration, while the equilibrium models assume the entire atmosphere is in hydrostatic and energetic equilibrium. The evolving atmospheres represent intermediate stages where hydrostatic equilibrium has been established in the chromosphere and corona, but the corona is not yet in energetic equilibrium with the flare heating source. Thus, for example, chromospheric evaporation is still in the process of occurring.

  11. Aeronomy of the current Martian atmosphere

    NASA Technical Reports Server (NTRS)

    Barth, C. A.; Stewart, A. I. F.; Bougher, S. W.; Hunten, D. M.; Bauer, S. J.; Nagy, A. F.

    1992-01-01

    The thermal structure of the Martian atmosphere, which varies diurnally, seasonally and episodically, is discussed. The atomic oxygen airglow at 1304 A is used to determine the density of atomic oxygen, and the 1216-A Lyman-alpha line is used to calculate the density of atomic hydrogen and, when coupled with the temperature measurement, the escape flux of atomic hydrogen. The most intense airglow is the IR atmospheric band of O2 at 1.27 micron that results from the photodissociation of ozone. The escape mechanism for atomic hydrogen is thermal, or Jeans, escape, while the atomic oxygen escape is caused by a nonthermal process, namely, the dissociative recombination of O2(+). The ratio of deuterium to hydrogen is enriched by a factor of 6. Three-dimensional models of the Mars thermospheric circulation show that planetary rotation has a significant effect on the wind, composition, and temperature structure.

  12. Method for the continuous fabrication of hydrogen storage alloy negative electrodes

    SciTech Connect

    Wolff, M.; Nuss, M.A.; Fetcenko, M.A.; Lijoi, A.L.

    1989-04-11

    A method is described for substantially continuously fabricating a large area, metal hydride electrochemical hydrogen storage alloy negative electrode for use in a rechargeable nickel-metal hydride battery, the method comprising the steps of: providing a continuous, wire mesh screen substrate; providing a measured amount of powdered metal hydride electrochemical hydrogen storage alloy material; continuously disposing a layer of the hydrogen storage alloy material into contact with the wire mesh screen substrate, in a substantially inert atmosphere; compacting the hydrogen storage alloy material into the wire mesh screen so as to form a green deposit thereof; pre-heating the green deposit of hydrogen storage alloy wire mesh screen; sintering the green deposit of hydrogen storage alloy wire mesh screen in an anhydrous, substantially oxygen free inert atmosphere so as to liberate moisture therefrom; and cooling the sintered hydrogen stage alloy wire mesh screen in a controlled hydrogen atmosphere so as to impart a partial charge thereto.

  13. Non-thermal hydrogen atoms in the terrestrial upper thermosphere.

    PubMed

    Qin, Jianqi; Waldrop, Lara

    2016-12-06

    Model predictions of the distribution and dynamical transport of hydrogen atoms in the terrestrial atmosphere have long-standing discrepancies with ultraviolet remote sensing measurements, indicating likely deficiencies in conventional theories regarding this crucial atmospheric constituent. Here we report the existence of non-thermal hydrogen atoms that are much hotter than the ambient oxygen atoms in the upper thermosphere. Analysis of satellite measurements indicates that the upper thermospheric hydrogen temperature, more precisely the mean kinetic energy of the atomic hydrogen population, increases significantly with declining solar activity, contrary to contemporary understanding of thermospheric behaviour. The existence of hot hydrogen atoms in the upper thermosphere, which is the key to reconciling model predictions and observations, is likely a consequence of low atomic oxygen density leading to incomplete collisional thermalization of the hydrogen population following its kinetic energization through interactions with hot atomic or ionized constituents in the ionosphere, plasmasphere or magnetosphere.

  14. Non-thermal hydrogen atoms in the terrestrial upper thermosphere

    PubMed Central

    Qin, Jianqi; Waldrop, Lara

    2016-01-01

    Model predictions of the distribution and dynamical transport of hydrogen atoms in the terrestrial atmosphere have long-standing discrepancies with ultraviolet remote sensing measurements, indicating likely deficiencies in conventional theories regarding this crucial atmospheric constituent. Here we report the existence of non-thermal hydrogen atoms that are much hotter than the ambient oxygen atoms in the upper thermosphere. Analysis of satellite measurements indicates that the upper thermospheric hydrogen temperature, more precisely the mean kinetic energy of the atomic hydrogen population, increases significantly with declining solar activity, contrary to contemporary understanding of thermospheric behaviour. The existence of hot hydrogen atoms in the upper thermosphere, which is the key to reconciling model predictions and observations, is likely a consequence of low atomic oxygen density leading to incomplete collisional thermalization of the hydrogen population following its kinetic energization through interactions with hot atomic or ionized constituents in the ionosphere, plasmasphere or magnetosphere. PMID:27922018

  15. Non-thermal hydrogen atoms in the terrestrial upper thermosphere

    NASA Astrophysics Data System (ADS)

    Qin, Jianqi; Waldrop, Lara

    2016-12-01

    Model predictions of the distribution and dynamical transport of hydrogen atoms in the terrestrial atmosphere have long-standing discrepancies with ultraviolet remote sensing measurements, indicating likely deficiencies in conventional theories regarding this crucial atmospheric constituent. Here we report the existence of non-thermal hydrogen atoms that are much hotter than the ambient oxygen atoms in the upper thermosphere. Analysis of satellite measurements indicates that the upper thermospheric hydrogen temperature, more precisely the mean kinetic energy of the atomic hydrogen population, increases significantly with declining solar activity, contrary to contemporary understanding of thermospheric behaviour. The existence of hot hydrogen atoms in the upper thermosphere, which is the key to reconciling model predictions and observations, is likely a consequence of low atomic oxygen density leading to incomplete collisional thermalization of the hydrogen population following its kinetic energization through interactions with hot atomic or ionized constituents in the ionosphere, plasmasphere or magnetosphere.

  16. Atmospheric Photochemistry

    NASA Technical Reports Server (NTRS)

    Massey, Harrie; Potter, A. E.

    1961-01-01

    The upper atmosphere offers a vast photochemical laboratory free from solid surfaces, so all reactions take place in the gaseous phase. At 30 km altitude the pressure has fallen to about one-hundredth of that at ground level, and we shall, rather arbitrarily, regard the upper atmosphere as beginning at that height. By a little less than 100 km the pressure has fallen to 10(exp -3) mm Hg and is decreasing by a power of ten for every 15 km increase in altitude. Essentially we are concerned then with the photochemistry of a nitrogen-oxygen mixture under low-pressure conditions in which photo-ionization, as well as photodissociation, plays an important part. Account must also be taken of the presence of rare constituents, such as water vapour and its decomposition products, including particularly hydroxyl, oxides of carbon, methane and, strangely enough, sodium, lithium and calcium. Many curious and unfamiliar reactions occur in the upper atmosphere. Some of them are luminescent, causing the atmosphere to emit a dim light called the airglow. Others, between gaseous ions and neutral molecules, are almost a complete mystery at this time. Similar interesting phenomena must occur in other planetary atmospheres, and they might be predicted if sufficient chemical information were available.

  17. Hydrogen Powered Military Vehicles: A Vision or Reality by 2040

    DTIC Science & Technology

    2004-01-01

    hydrogen is used to power the year 2040 generation of the U.S. military vehicles, it will accomplish twice the efficiency of today’s gasoline engines... gasoline engines, with zero air emissions released into the atmosphere. The hydrogen powered military vehicle will become a reality by 2040. The...referenced to gasoline Introduction What follows is a study on

  18. Atmospheric radiation

    SciTech Connect

    Harshvardhan, M.R. )

    1991-01-01

    Studies of atmospheric radiative processes are summarized for the period 1987-1990. Topics discussed include radiation modeling; clouds and radiation; radiative effects in dynamics and climate; radiation budget and aerosol effects; and gaseous absorption, particulate scattering and surface reflection. It is concluded that the key developments of the period are a defining of the radiative forcing to the climate system by trace gases and clouds, the recognition that cloud microphysics and morphology need to be incorporated not only into radiation models but also climate models, and the isolation of a few important unsolved theoretical problems in atmospheric radiation.

  19. Hydrogen embrittlement in nickel-hydrogen cells

    NASA Technical Reports Server (NTRS)

    Gross, Sidney

    1989-01-01

    It was long known that many strong metals can become weakened and brittle as the result of the accumulation of hydrogen within the metal. When the metal is stretched, it does not show normal ductile properties, but fractures prematurely. This problem can occur as the result of a hydrogen evolution reaction such as corrosion or electroplating, or due to hydrogen in the environment at the metal surface. High strength alloys such as steels are especially susceptible to hydrogen embrittlement. Nickel-hydrogen cells commonly use Inconel 718 alloy for the pressure container, and this also is susceptible to hydrogen embrittlement. Metals differ in their susceptibility to embrittlement. Hydrogen embrittlement in nickel-hydrogen cells is analyzed and the reasons why it may or may not occur are discussed. Although Inconel 718 can display hydrogen embrittlement, experience has not identified any problem with nickel-hydrogen cells. No hydrogen embrittlement problem is expected with the 718 alloy pressure container used in nickel-hydrogen cells.

  20. Ultrasonically improved semi-hydrogenation of alkynes to (Z-)alkenes over novel lead-free Pd/Boehmite catalysts.

    PubMed

    Wu, Zhilin; Cravotto, Giancarlo; Gaudino, Emanuela Calcio; Giacomino, Agnese; Medlock, Jonathan; Bonrath, Werner

    2017-03-01

    This paper reports the application of ultrasound in the semi-hydrogenation of alkynes over two novel Pd/Boehmite catalysts. The semi-hydrogenations of phenylacetylene, diphenylacetylene and 2-butyne-1,4-diol have either been investigated in an ultrasonic bath under atmospheric hydrogen pressure, or in an ultrasonic horn reactor under 0.1-0.5MPa hydrogen pressure. Alkyne hydrogenation was suppressed by sonication under atmospheric hydrogen pressure, but promoted by sonication under 0.1MPa of hydrogen pressure. Sonication increased selectivity towards the semi-hydrogenated products in both cases. Catalyst loading, hydrogen pressure, temperature and the presence of quinoline, all impacted on hydrogenation rate, activity and selectivity to semi-hydrogenated products. Palladium leaching from the catalyst was evaluated in ethanol and hexane both under plain stirring and sonication.

  1. Atmospheric Waves

    NASA Technical Reports Server (NTRS)

    2007-01-01

    With its Multispectral Visible Imaging Camera (MVIC), half of the Ralph instrument, New Horizons captured several pictures of mesoscale gravity waves in Jupiter's equatorial atmosphere. Buoyancy waves of this type are seen frequently on Earth - for example, they can be caused when air flows over a mountain and a regular cloud pattern forms downstream. In Jupiter's case there are no mountains, but if conditions in the atmosphere are just right, it is possible to form long trains of these small waves. The source of the wave excitation seems to lie deep in Jupiter's atmosphere, below the visible cloud layers at depths corresponding to pressures 10 times that at Earth's surface. The New Horizons measurements showed that the waves move about 100 meters per second faster than surrounding clouds; this is about 25% of the speed of sound on Earth and is much greater than current models of these waves predict. Scientists can 'read' the speed and patterns these waves to learn more about activity and stability in the atmospheric layers below.

  2. Atmospheric humidity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water vapor plays a critical role in earth's atmosphere. It helps to maintain a habitable surface temperature through absorption of outgoing longwave radiation, and it transfers trmendous amounts of energy from the tropics toward the poles by absorbing latent heat during evaporation and subsequently...

  3. Hydrogen supply system

    SciTech Connect

    Teitel, R.J.

    1981-11-24

    A system for supplying hydrogen to an apparatus which utilizes hydrogen contains a metal hydride hydrogen supply component and a microcavity hydrogen storage hydrogen supply component which in tandem supply hydrogen for the apparatus. The metal hydride hydrogen supply component includes a first storage tank filled with a composition which is capable of forming a metal hydride of such a nature that the hydride will release hydrogen when heated but will absorb hydrogen when cooled. This first storage tank is equipped with a heat exchanger for both adding heat to and extracting heat from the composition to regulate the absorption/deabsorption of hydrogen from the composition. The microcavity hydrogen storage hydrogen supply component includes a second tank containing the microcavity hydrogen supply. The microcavity hydrogen storage contains hydrogen held under high pressure within individual microcavities. The hydrogen is released from the microcavities by heating the cavities. This heating is accomplished by including within the tank for the microcavity hydrogen storage a heating element.

  4. Lunar atmospheric composition results from Apollo 17

    NASA Technical Reports Server (NTRS)

    Hoffmann, J. H.; Hodges, R. R., Jr.; Johnson, F. S.; Evans, D. E.

    1973-01-01

    The Apollo 17 mass spectrometer has confirmed the existence of helium, neon, argon, and possibly molecular hydrogen in the lunar atmosphere. Helium and neon concentrations are in agreement with model predictions based on the solar wind as a source and their being noncondensable gases. Ar-40 and Ar-36 both exhibit a predawn enhancement which indicates that they are condensable gases on the nightside and are re-released into the atmosphere at the sunrise terminator. Hydrogen probably exists in the lunar atmosphere in the molecular rather than atomic state, having been released from the surface in the molecular form. Total nighttime gas concentration of known species in the lunar atmosphere is 200,000 molecules/cu cm.

  5. Hydrogen sulphide.

    PubMed

    Guidotti, T L

    1996-10-01

    Hydrogen sulphide (H2S) is the primary chemical hazard in natural gas production in 'sour' gas fields. It is also a hazard in sewage treatment and manure-containment operations, construction in wetlands, pelt processing, certain types of pulp and paper production, and any situation in which organic material decays or inorganic sulphides exist under reducing conditions. H2S dissociates into free sulphide in the circulation. Sulphide binds to many macromolecules, among them cytochrome oxidase. Although this is undoubtedly an important mechanism of toxicity due to H2S, there may be others H2S provides little opportunity for escape at high concentrations because of the olfactory paralysis it causes, the steep exposure-response relationships, and the characteristically sudden loss of consciousness it can cause which is colloquially termed 'knockdown.' Other effects may include mucosal irritation, which is associated at lower concentrations with a keratoconjunctivitis called 'gas eye' and at higher concentrations with risk of pulmonary oedema. Chronic central nervous system sequelae may possibly follow repeated knockdowns: this is controversial and the primary effects of H2S may be confounded by anoxia or head trauma. Treatment is currently empirical, with a combination of nitrite and hyperbaric oxygen preferred. The treatment regimen is not ideal and carries some risk.

  6. Earth's earliest atmospheres.

    PubMed

    Zahnle, Kevin; Schaefer, Laura; Fegley, Bruce

    2010-10-01

    Earth is the one known example of an inhabited planet and to current knowledge the likeliest site of the one known origin of life. Here we discuss the origin of Earth's atmosphere and ocean and some of the environmental conditions of the early Earth as they may relate to the origin of life. A key punctuating event in the narrative is the Moon-forming impact, partly because it made Earth for a short time absolutely uninhabitable, and partly because it sets the boundary conditions for Earth's subsequent evolution. If life began on Earth, as opposed to having migrated here, it would have done so after the Moon-forming impact. What took place before the Moon formed determined the bulk properties of the Earth and probably determined the overall compositions and sizes of its atmospheres and oceans. What took place afterward animated these materials. One interesting consequence of the Moon-forming impact is that the mantle is devolatized, so that the volatiles subsequently fell out in a kind of condensation sequence. This ensures that the volatiles were concentrated toward the surface so that, for example, the oceans were likely salty from the start. We also point out that an atmosphere generated by impact degassing would tend to have a composition reflective of the impacting bodies (rather than the mantle), and these are almost without exception strongly reducing and volatile-rich. A consequence is that, although CO- or methane-rich atmospheres are not necessarily stable as steady states, they are quite likely to have existed as long-lived transients, many times. With CO comes abundant chemical energy in a metastable package, and with methane comes hydrogen cyanide and ammonia as important albeit less abundant gases.

  7. Rayleigh Scattering by Helium in Stellar Atmospheres

    NASA Astrophysics Data System (ADS)

    Fišák, J.; Kubát, J.; Krtička, J.

    2017-02-01

    We study the influence of Rayleigh scattering by helium on synthetic spectra and stellar atmosphere models. Rayleigh scattering by helium is often neglected in hot star atmosphere models. This approximation is justified by the small population of helium in stars with solar composition (about 10% by number) and lower Rayleigh scattering total cross section of helium with respect to neutral hydrogen. However, for stars with large helium abundances Rayleigh scattering by helium can be a significant opacity source.

  8. Hydrogen permeation, diffusion and solubility in IN-100 and Waspaloy

    NASA Technical Reports Server (NTRS)

    Khan, A. S.; Peterson, D. T.

    1990-01-01

    An attempt has been made to determine the permeation rate of hydrogen in IN-100 and Waspaloy by determining the evolution rate of hydrogen from a closed capsule of the test materials. Enclosed vanadium hydride was the source of hydrogen in the capsule. The presentation discusses the treatment of data and assesses the validity of the techniques in permeation measurement. In addition to permeation experiments, the solubility and diffusion of hydrogen in IN-100 and Waspaloy were also determined. For hydrogen diffusion in Waspaloy, Delta H was 38.5 kJ and D(0) was 0.0026 sq cm/sec. For IN-100, Delta H was 68.2 kJ and D(0) was 0.059 sq cm /sec. Both IN-100 and Waspaloy exhibited limited solubility of hydrogen at pressures up to 340 atmospheres hydrogen.

  9. Composition for absorbing hydrogen

    DOEpatents

    Heung, Leung K.; Wicks, George G.; Enz, Glenn L.

    1995-01-01

    A hydrogen absorbing composition. The composition comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix. A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen-absorbing material and solidified to form a porous glass matrix with the hydrogen-absorbing material dispersed uniformly throughout the matrix. The glass matrix has pores large enough to allow gases having hydrogen to pass through the matrix, yet small enough to hold the particles dispersed within the matrix so that the hydrogen-absorbing particles are not released during repeated hydrogen absorption/desorption cycles.

  10. Composition for absorbing hydrogen

    DOEpatents

    Heung, L.K.; Wicks, G.G.; Enz, G.L.

    1995-05-02

    A hydrogen absorbing composition is described. The composition comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix. A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen-absorbing material and solidified to form a porous glass matrix with the hydrogen-absorbing material dispersed uniformly throughout the matrix. The glass matrix has pores large enough to allow gases having hydrogen to pass through the matrix, yet small enough to hold the particles dispersed within the matrix so that the hydrogen-absorbing particles are not released during repeated hydrogen absorption/desorption cycles.

  11. Vanadium diaphragm electrode serves as hydrogen diffuser in lithium hydride cell

    NASA Technical Reports Server (NTRS)

    Crouthamel, C. E.; Heinrich, R. R.; Johnson, C. E.

    1967-01-01

    Lithium hydride cell uses vanadium diaphragm electrode as a hydrogen diffuser. Vanadium is high in hydrogen gas solubility and permeability, is least sensitive to adverse surface effects, maintains good mechanical strength in hydrogen atmospheres, and appears to be compatible with all alkali-halide electrolytes and lithium metals.

  12. Thermal Battery Operating Gas Atmosphere Control and Heat Transfer Optimization

    DTIC Science & Technology

    2012-09-01

    Approved for public release; distribution unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT The effects of gases and gas mixtures on global...highly effective in atmospheres of pure hydrogen and are potentially useful in mixtures of hydrogen and air. Barium chromate (BaCrO4) placed in contact...15 Figure 9. Gas gettering from a 79.6/20.4 volume percent hydrogen/air mixture

  13. Planetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Encrenaz, T.; Murdin, P.

    2000-11-01

    Planetary atmospheres are the external gaseous envelopes which surround the planets. In the case of the telluric planets, they represent only a negligible fraction of their mass, but they play an essential role in the energy balance between the surfaces and the Sun. In the case of the GIANT PLANETS, which are mostly gaseous, they account for a large fraction of their total mass and constitute the...

  14. Atmospheric Acoustics

    NASA Astrophysics Data System (ADS)

    Heimann, Dietrich; Schady, Arthur; Feng, Joseph

    This chapter deals with sound propagation in the atmosphere, which is an important link in the functional chain from noise emissions from aircraft, road and rail vehicles, and wind turbines to noise perception. The principle processes in outdoor sound propagation are explained. They include refraction, diffraction, and reflection. Two sound propagation models for scientific applications are briefly outlined. Finally, three illustrative applications and their results are discussed.

  15. Thermodynamic properties of hydrogen-helium plasmas.

    NASA Technical Reports Server (NTRS)

    Nelson, H. F.

    1972-01-01

    Calculation of the thermodynamic properties of an atomic hydrogen-helium plasma for postulated conditions present in a stagnation shock layer of a spacecraft entering the atmosphere of Jupiter. These properties can be used to evaluate transport properties, to calculate convective heating, and to investigate nonequilibrium behavior. The calculations have been made for temperatures from 10,000 to 100,000 K, densities of 10 to the minus 7th and .00001 g cu cm, and three plasma compositions: pure hydrogen, 50% hydrogen/50% helium, and pure helium. The shock layer plasma consists of electrons, protons, atomic hydrogen, atomic helium, singly ionized helium, and doubly atomized helium. The thermodynamic properties which have been investigated are: pressure, average molecular weight, internal energy, enthalpy, entropy, specific heat, and isentropic speed of sound. A consistent model was used for the reduction of the ionization potential in the calculation of the partition functions.

  16. Hydrogen isotope separation installation for tritium facility

    SciTech Connect

    Andreev, B.M.; Perevezentsev, A.N.; Selivanenko, I.L.; Tenyaev, B.N.; Vedeneev, A.I.; Golubkov, A.N.

    1995-10-01

    The separation of hydrogen isotopes in the hydrogen-palladium system in sectioned separation columns with the simulation of counter-current isotopic exchange is described. The separation efficiency of sectioned columns is investigated with the experimental installation as a function of various parameters. The separation of deuterium-tritium mixtures with high tritium concentrations is tested with the pilot installation operating at room temperature and atmospheric hydrogen pressure. Due to very high separation efficiency, flexibility and simplicity of operation separation installations with sectioned columns are ideally suitable for tritium laboratories and facilities dealing with separation of hydrogen isotopes. Estimation of applicability of sectioned columns for regeneration of exhaust gas in a fuel cycle of thermonuclear reactors, such as JET and ITER, shows the number of advantages of separation installations with sectioned columns. 12 refs., 3 figs., 2 tabs.

  17. A Few Facts about Hydrogen [and] Hydrogen Bibliography.

    ERIC Educational Resources Information Center

    Hinds, H. Roger

    Divided into two sections, this publication presents facts about and the characteristics of hydrogen and a bibliography on hydrogen. The first section lists nine facts on what hydrogen is, four on where hydrogen is found, nine on how hydrogen is used, nine on how hydrogen can be used, and 14 on how hydrogen is made. Also included are nine…

  18. Ignition and flame characteristics of cryogenic hydrogen releases

    SciTech Connect

    Panda, Pratikash P.; Hecht, Ethan S.

    2017-01-01

    In this work, under-expanded cryogenic hydrogen jets were investigated experimentally for their ignition and flame characteristics. The test facility described herein, was designed and constructed to release hydrogen at a constant temperature and pressure, to study the dispersion and thermo-physical properties of cryogenic hydrogen releases and flames. In this study, a non-intrusive laser spark focused on the jet axis was used to measure the maximum ignition distance. The radiative power emitted by the corresponding jet flames was also measured for a range of release scenarios from 37 K to 295 K, 2–6 barabs through nozzles with diameters from 0.75 to 1.25 mm. The maximum ignition distance scales linearly with the effective jet diameter (which scales as the square root of the stagnant fluid density). A 1-dimensional (stream-wise) cryogenic hydrogen release model developed previously at Sandia National Laboratories (although this model is not yet validated for cryogenic hydrogen) was exercised to predict that the mean mole fraction at the maximum ignition distance is approximately 0.14, and is not dependent on the release conditions. The flame length and width were extracted from visible and infra-red flame images for several test cases. The flame length and width both scale as the square root of jet exit Reynolds number, as reported in the literature for flames from atmospheric temperature hydrogen. As shown in previous studies for ignited atmospheric temperature hydrogen, the radiative power from the jet flames of cold hydrogen scales as a logarithmic function of the global flame residence time. The radiative heat flux from jet flames of cold hydrogen is higher than the jet flames of atmospheric temperature hydrogen, for a given mass flow rate, due to the lower choked flow velocity of low-temperature hydrogen. Lastly, this study provides critical information with regard to the development of models to inform the safety codes and standards of hydrogen

  19. Ignition and flame characteristics of cryogenic hydrogen releases

    DOE PAGES

    Panda, Pratikash P.; Hecht, Ethan S.

    2017-01-01

    In this work, under-expanded cryogenic hydrogen jets were investigated experimentally for their ignition and flame characteristics. The test facility described herein, was designed and constructed to release hydrogen at a constant temperature and pressure, to study the dispersion and thermo-physical properties of cryogenic hydrogen releases and flames. In this study, a non-intrusive laser spark focused on the jet axis was used to measure the maximum ignition distance. The radiative power emitted by the corresponding jet flames was also measured for a range of release scenarios from 37 K to 295 K, 2–6 barabs through nozzles with diameters from 0.75 tomore » 1.25 mm. The maximum ignition distance scales linearly with the effective jet diameter (which scales as the square root of the stagnant fluid density). A 1-dimensional (stream-wise) cryogenic hydrogen release model developed previously at Sandia National Laboratories (although this model is not yet validated for cryogenic hydrogen) was exercised to predict that the mean mole fraction at the maximum ignition distance is approximately 0.14, and is not dependent on the release conditions. The flame length and width were extracted from visible and infra-red flame images for several test cases. The flame length and width both scale as the square root of jet exit Reynolds number, as reported in the literature for flames from atmospheric temperature hydrogen. As shown in previous studies for ignited atmospheric temperature hydrogen, the radiative power from the jet flames of cold hydrogen scales as a logarithmic function of the global flame residence time. The radiative heat flux from jet flames of cold hydrogen is higher than the jet flames of atmospheric temperature hydrogen, for a given mass flow rate, due to the lower choked flow velocity of low-temperature hydrogen. Lastly, this study provides critical information with regard to the development of models to inform the safety codes and standards of hydrogen

  20. Validation Testing of Hydrogen Generation Technology

    SciTech Connect

    Smith, Barton; Toops, Todd J

    2007-12-01

    This report describes the results of testing performed by ORNL for Photech Energies, Inc. The objective of the testing was to evaluate the efficacy of Photech's hydrogen generation reactor technology, which produces gaseous hydrogen through electrolysis. Photech provided several prototypes of their proprietary reactor for testing and the ancillary equipment, such as power supplies and electrolyte solutions, required for proper operation of the reactors. ORNL measured the production of hydrogen gas (volumetric flow of hydrogen at atmospheric pressure) as a function of input power and analyzed the composition of the output stream to determine the purity of the hydrogen content. ORNL attempted measurements on two basic versions of the prototype reactors-one version had a clear plastic outer cylinder, while another version had a stainless steel outer cylinder-but was only able to complete measurements on reactors in the plastic version. The problem observed in the stainless steel reactors was that in these reactors most of the hydrogen was produced near the anodes along with oxygen and the mixed gases made it impossible to determine the amount of hydrogen produced. In the plastic reactors the production of hydrogen gas increased monotonically with input power, and the flow rates increased faster at low input powers than they did at higher input powers. The maximum flow rate from the cathode port measured during the tests was 0.85 LPM at an input power of about 1100 W, an electrolyte concentration of 20%. The composition of the flow from the cathode port was primarily hydrogen and water vapor, with some oxygen and trace amounts of carbon dioxide. An operational mode that occurs briefly during certain operating conditions, and is characterized by flashes of light and violent bubbling near the cathode, might be attributable to the combustion of hydrogen and oxygen in the electrolyte solution.

  1. Electrochemical Hydrogen Compressor

    SciTech Connect

    David P. Bloomfield; Brian S. MacKenzie

    2006-05-01

    The Electrochemical Hydrogen Compressor EHC was evaluated against DOE applications for compressing hydrogen at automobile filling stations, in future hydrogen pipelines and as a commercial replacement for conventional diaphragm hydrogen compressors. It was also evaluated as a modular replacement for the compressors used in petrochemical refineries. If the EHC can be made inexpensive, reliable and long lived then it can satisfy all these applications save pipelines where the requirements for platinum catalyst exceeds the annual world production. The research performed did not completely investigate Molybdenum as a hydrogen anode or cathode, it did show that photoetched 316 stainless steel is inadequate for an EHC. It also showed that: molybdenum bipolar plates, photochemical etching processes, and Gortex Teflon seals are too costly for a commercial EHC. The use of carbon paper in combination with a perforated thin metal electrode demonstrated adequate anode support strength, but is suspect in promoting galvanic corrosion. The nature of the corrosion mechanisms are not well understood, but locally high potentials within the unit cell package are probably involved. The program produced a design with an extraordinary high cell pitch, and a very low part count. This is one of the promising aspects of the redesigned EHC. The development and successful demonstration of the hydraulic cathode is also important. The problem of corrosion resistant metal bipolar plates is vital to the development of an inexpensive, commercial PEM fuel cell. Our research suggests that there is more to the corrosion process in fuel cells and electrochemical compressors than simple, steady state, galvanic stability. It is an important area for scientific investigation. The experiments and analysis conducted lead to several recommended future research directions. First, we need a better understanding of the corrosion mechanisms involved. The diagnosis of experimental cells with titration to

  2. Correlation of theory and experiment for high-pressure hydrogen

    NASA Technical Reports Server (NTRS)

    Hoover, W. G.; Ross, M.; Bender, C. F.; Rogers, F. J.; Olness, R. J.

    1972-01-01

    Recent quantum calculations and high-pressure experiments both agree on the magnitude of the forces with which hydrogen molecules interact. The calculated forces have to be determined in two steps: the repulsion is determined by Hartree-Fock calculations while the attraction is deduced semiempirically. The experimental forces are inferred from recent data on hydrogen shockcompressed to 214 kbar. The agreement indicates the usefulness of a pair-potential description of dense hydrogen and suggests, using potentials consistent with both theory and experiment, that pressures of at least 1.7 Mbar will be required to make metallic hydrogen. The expected lifetime of the metal at atmospheric pressure is very short.

  3. Atmospheric science

    NASA Technical Reports Server (NTRS)

    Hamill, Patrick; Ackerman, Thomas; Clarke, Antony; Goodman, Jindra; Levin, Zev; Tomasko, Martin; Toon, O. Brian; Whitten, Robert

    1987-01-01

    The following types of experiments for a proposed Space Station Microgravity Particle Research Facility are described: (1) growth of liquid water drop populations; (2) coalescence; (3) drop breakup; (4) breakup of freezing drops; (5) ice nucleation for large aerosols or bacteria; (6) scavenging of gases, for example, SO2 oxidation; (7) phoretic forces, i.e., thermophoresis versus diffusiophoresis; (8) Rayleigh bursting of drops; (9) charge separation due to collisions of rimed and unrimed ice; (10) charged drop dynamics; (11) growth of particles in other planetary atmospheres; and (12) freezing and liquid-liquid evaporation. The required capabilities and desired hardware for the facility are detailed.

  4. Hydrogen energy systems studies

    SciTech Connect

    Ogden, J.M.; Kreutz, T.G.; Steinbugler, M.

    1996-10-01

    In this report the authors describe results from technical and economic assessments carried out during the past year with support from the USDOE Hydrogen R&D Program. (1) Assessment of technologies for small scale production of hydrogen from natural gas. Because of the cost and logistics of transporting and storing hydrogen, it may be preferable to produce hydrogen at the point of use from more readily available energy carriers such as natural gas or electricity. In this task the authors assess near term technologies for producing hydrogen from natural gas at small scale including steam reforming, partial oxidation and autothermal reforming. (2) Case study of developing a hydrogen vehicle refueling infrastructure in Southern California. Many analysts suggest that the first widespread use of hydrogen energy is likely to be in zero emission vehicles in Southern California. Several hundred thousand zero emission automobiles are projected for the Los Angeles Basin alone by 2010, if mandated levels are implemented. Assuming that hydrogen vehicles capture a significant fraction of this market, a large demand for hydrogen fuel could evolve over the next few decades. Refueling a large number of hydrogen vehicles poses significant challenges. In this task the authors assess near term options for producing and delivering gaseous hydrogen transportation fuel to users in Southern California including: (1) hydrogen produced from natural gas in a large, centralized steam reforming plant, and delivered to refueling stations via liquid hydrogen truck or small scale hydrogen gas pipeline, (2) hydrogen produced at the refueling station via small scale steam reforming of natural gas, (3) hydrogen produced via small scale electrolysis at the refueling station, and (4) hydrogen from low cost chemical industry sources (e.g. excess capacity in refineries which have recently upgraded their hydrogen production capacity, etc.).

  5. Concentration of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2006-01-01

    Methods for concentrating hydrogen peroxide solutions have been described. The methods utilize a polymeric membrane separating a hydrogen peroxide solution from a sweep gas or permeate. The membrane is selective to the permeability of water over the permeability of hydrogen peroxide, thereby facilitating the concentration of the hydrogen peroxide solution through the transport of water through the membrane to the permeate. By utilizing methods in accordance with the invention, hydrogen peroxide solutions of up to 85% by volume or higher may be generated at a point of use without storing substantial quantities of the highly concentrated solutions and without requiring temperatures that would produce explosive mixtures of hydrogen peroxide vapors.

  6. Hydrogen conference: Workshop proceedings

    SciTech Connect

    Serfass, J.; Bugel, L. )

    1989-10-01

    This meeting was designed to encourage discussion of today's US industrial, utility, space and environmental interests in hydrogen and tommorrow's use of hydrogen as an energy system. The meeting began with a general session during which speakers gave presentations on a variety of hydrogen topics. Discussion following each presentation was lively. Some of the major points of discussion were: interpretation of global warming evidence; relevance of global warming to the interest in hydrogen; cost of hydrogen derived from fossil fuels vs. nuclear vs. solar; likely future importance of hydrogen -- major energy system vs. niche player. A number of interesting points were raised and data presented by speakers and participants. Highlights are presented.

  7. [Hydrogen peroxide in the troposphere].

    PubMed

    Pehnec, Gordana

    2007-06-01

    The past few decades saw a rising interest in the role of hydrogen peroxide (H2O2) in atmospheric chemistry and its contribution to the formation of free radicals. Free radicals (oxidants) are formed by photochemical reactions between ozone and H2O2. Free radicals formed within cells can oxidise biomolecules, and this may lead to cell death and tissue injury. For this reason, free radicals are believed to cause more than 100 diseases. H2O2 has been suggested as a better indicator of atmospheric oxidation capacity than ozone. Atmospheric H2O2 can appear in the gas phase or in the aqueous phase. It shows typical diurnal and seasonal variations. However, measurements of H2O2 with expensive and sophisticated equipment are rare and limited to but a few sites in the world. Measurements in Greenland ice cores showed that H2O2 concentrations increased over the last 200 years and most of the increase has occurred over the last 20 years. Evaluations show that concentrations will still rise as a result of decreasing SO2 emission. H2O2 measurements have not been carried out in Croatia until now, and, accompanied by the existing longterm measurements of ozone and nitrogen oxides, they will provide an idea of the oxidative capacity of the atmosphere and its influence on oxidative stress.

  8. Heterogeneous chemistry in the atmosphere of Mars.

    PubMed

    Lefèvre, Franck; Bertaux, Jean-Loup; Clancy, R Todd; Encrenaz, Thérèse; Fast, Kelly; Forget, François; Lebonnois, Sébastien; Montmessin, Franck; Perrier, Séverine

    2008-08-21

    Hydrogen radicals are produced in the martian atmosphere by the photolysis of water vapour and subsequently initiate catalytic cycles that recycle carbon dioxide from its photolysis product carbon monoxide. These processes provide a qualitative explanation for the stability of the atmosphere of Mars, which contains 95 per cent carbon dioxide. Balancing carbon dioxide production and loss based on our current understanding of the gas-phase chemistry in the martian atmosphere has, however, proven to be difficult. Interactions between gaseous chemical species and ice cloud particles have been shown to be key factors in the loss of polar ozone observed in the Earth's stratosphere, and may significantly perturb the chemistry of the Earth's upper troposphere. Water-ice clouds are also commonly observed in the atmosphere of Mars and it has been suggested previously that heterogeneous chemistry could have an important impact on the composition of the martian atmosphere. Here we use a state-of-the-art general circulation model together with new observations of the martian ozone layer to show that model simulations that include chemical reactions occurring on ice clouds lead to much improved quantitative agreement with observed martian ozone levels in comparison with model simulations based on gas-phase chemistry alone. Ozone is readily destroyed by hydrogen radicals and is therefore a sensitive tracer of the chemistry that regulates the atmosphere of Mars. Our results suggest that heterogeneous chemistry on ice clouds plays an important role in controlling the stability and composition of the martian atmosphere.

  9. Chemistry and evolution of Titan's atmosphere

    NASA Technical Reports Server (NTRS)

    Strobel, D. F.

    1982-01-01

    The chemistry and evolution of Titan's atmosphere are reviewed, in light of the scientific findings from the Voyager mission. It is argued that the present N2 atmosphere may be Titan's initial atmosphere, rather than one photochemically derived from an original NH3 atmosphere. The escape rate of hydrogen from Titan is controlled by photochemical production from hydrocarbons. CH4 is irreversibly converted to less hydrogen-rich hydrocarbons, which over geologic time accumulate on the surface to a layer thickness of about 0.5 km. Magnetospheric electrons interacting with Titan's exosphere may dissociate enough N2 into hot, escaping N atoms to remove about 0.2 of Titan's present atmosphere over geologic time. The energy dissipation of magnetospheric electrons exceeds solar EUV energy deposition in Titan's atmosphere by an order of magnitude, and is the principal driver of nitrogen photochemistry. The environmental conditions in Titan's upper atmosphere are favorable to building up complex molecules, particularly in the north polar cap region.

  10. Chemical/hydrogen energy systems analysis

    NASA Astrophysics Data System (ADS)

    Beller, M.

    1982-12-01

    Four hydrogen energy technologies are addressed including: hydrogen recovery from hydrogen separation using hydride technology, photochemical hydrogen production, anode depolarization in electrolytic hydrogen production.

  11. Deviations from LTE in a stellar atmosphere

    NASA Technical Reports Server (NTRS)

    Kalkofen, W.; Klein, R. I.; Stein, R. F.

    1979-01-01

    Deviations for LTE are investigated in an atmosphere of hydrogen atoms with one bound level, satisfying the equations of radiative, hydrostatic, and statistical equilibrium. The departure coefficient and the kinetic temperature as functions of the frequency dependence of the radiative cross section are studied analytically and numerically. Near the outer boundary of the atmosphere, the departure coefficient is smaller than unity when the radiative cross section grows with frequency faster than with the square of frequency; it exceeds unity otherwise. Far from the boundary the departure coefficient tends to exceed unity for any frequency dependence of the radiative cross section. Overpopulation always implies that the kinetic temperature in the statistical-equilibrium atmosphere is higher than the temperature in the corresponding LTE atmosphere. Upper and lower bounds on the kinetic temperature are given for an atmosphere with deviations from LTE only in the optically shallow layers when the emergent intensity can be described by a radiation temperature.

  12. Hydrogen transport membranes

    DOEpatents

    Mundschau, Michael V.

    2005-05-31

    Composite hydrogen transport membranes, which are used for extraction of hydrogen from gas mixtures are provided. Methods are described for supporting metals and metal alloys which have high hydrogen permeability, but which are either too thin to be self supporting, too weak to resist differential pressures across the membrane, or which become embrittled by hydrogen. Support materials are chosen to be lattice matched to the metals and metal alloys. Preferred metals with high permeability for hydrogen include vanadium, niobium, tantalum, zirconium, palladium, and alloys thereof. Hydrogen-permeable membranes include those in which the pores of a porous support matrix are blocked by hydrogen-permeable metals and metal alloys, those in which the pores of a porous metal matrix are blocked with materials which make the membrane impervious to gases other than hydrogen, and cermets fabricated by sintering powders of metals with powders of lattice-matched ceramic.

  13. Hydrogen production by Cyanobacteria

    PubMed Central

    Dutta, Debajyoti; De, Debojyoti; Chaudhuri, Surabhi; Bhattacharya, Sanjoy K

    2005-01-01

    The limited fossil fuel prompts the prospecting of various unconventional energy sources to take over the traditional fossil fuel energy source. In this respect the use of hydrogen gas is an attractive alternate source. Attributed by its numerous advantages including those of environmentally clean, efficiency and renew ability, hydrogen gas is considered to be one of the most desired alternate. Cyanobacteria are highly promising microorganism for hydrogen production. In comparison to the traditional ways of hydrogen production (chemical, photoelectrical), Cyanobacterial hydrogen production is commercially viable. This review highlights the basic biology of cynobacterial hydrogen production, strains involved, large-scale hydrogen production and its future prospects. While integrating the existing knowledge and technology, much future improvement and progress is to be done before hydrogen is accepted as a commercial primary energy source. PMID:16371161

  14. Hydrogen production by Cyanobacteria.

    PubMed

    Dutta, Debajyoti; De, Debojyoti; Chaudhuri, Surabhi; Bhattacharya, Sanjoy K

    2005-12-21

    The limited fossil fuel prompts the prospecting of various unconventional energy sources to take over the traditional fossil fuel energy source. In this respect the use of hydrogen gas is an attractive alternate source. Attributed by its numerous advantages including those of environmentally clean, efficiency and renew ability, hydrogen gas is considered to be one of the most desired alternate. Cyanobacteria are highly promising microorganism for hydrogen production. In comparison to the traditional ways of hydrogen production (chemical, photoelectrical), Cyanobacterial hydrogen production is commercially viable. This review highlights the basic biology of cynobacterial hydrogen production, strains involved, large-scale hydrogen production and its future prospects. While integrating the existing knowledge and technology, much future improvement and progress is to be done before hydrogen is accepted as a commercial primary energy source.

  15. Atmospheric Propagation

    NASA Technical Reports Server (NTRS)

    Embleton, Tony F. W.; Daigle, Gilles A.

    1991-01-01

    Reviewed here is the current state of knowledge with respect to each basic mechanism of sound propagation in the atmosphere and how each mechanism changes the spectral or temporal characteristics of the sound received at a distance from the source. Some of the basic processes affecting sound wave propagation which are present in any situation are discussed. They are geometrical spreading, molecular absorption, and turbulent scattering. In geometrical spreading, sound levels decrease with increasing distance from the source; there is no frequency dependence. In molecular absorption, sound energy is converted into heat as the sound wave propagates through the air; there is a strong dependence on frequency. In turbulent scattering, local variations in wind velocity and temperature induce fluctuations in phase and amplitude of the sound waves as they propagate through an inhomogeneous medium; there is a moderate dependence on frequency.

  16. Atmosphere Analyzer

    NASA Technical Reports Server (NTRS)

    1982-01-01

    California Measurements, Inc.'s model PC-2 Aerosol Particle Analyzer is produced in both airborne and ground-use versions. Originating from NASA technology, it is a quick and accurate method of detecting minute amounts of mass loadings on a quartz crystal -- offers utility as highly sensitive detector of fine particles suspended in air. When combined with suitable air delivery system, it provides immediate information on the size distribution and mass concentrations of aerosols. William Chiang, obtained a NASA license for multiple crystal oscillator technology, and initially developed a particle analyzer for NASA use with Langley Research Center assistance. Later his company produced the modified PC-2 for commercial applications Brunswick Corporation uses the device for atmospheric research and in studies of smoke particles in Fires. PC-2 is used by pharmaceutical and chemical companies in research on inhalation toxicology and environmental health. Also useful in testing various filters for safety masks and nuclear installations.

  17. Hydrogen storage via polyhydride complexes

    SciTech Connect

    Jensen, C.M.; Zidan, R.A.

    1998-08-01

    The reversible dehydrogenation of NaAlH{sub 4} is catalyzed in toluene slurries of the NaAlH{sub 4} containing the pincer complex, IrH{sub 4} {l_brace}C{sub 6}H{sub 3}-2,6-(CH{sub 2}PBu{sup t}{sub 2}){sub 2}{r_brace}. The rates of the pincer complex catalyzed dehydrogenation are about five times greater those previously found for NaAlH{sub 4} that was doped with titanium through a wet chemistry method. Homogenization of NaAlH{sub 4} with 2 mole % Ti(OBu{sup n}){sub 4} under an atmosphere of argon produces a novel titanium containing material. TPD measurements show that the dehydrogenation of this material occurs about 30 C lower than that previously found for wet titanium doped NaAlH{sub 4}. In further contrast to wet doped NaAlH{sub 4}, the dehydrogenation kinetics and hydrogen capacity of the novel material are undiminished over several dehydriding/hydriding cycles. Rehydrogenation of the titanium doped material occurs readily at 170 C under 150 atm of hydrogen. TPD measurements show that about 80% of the original hydrogen content (4.2 wt%) can be restored under these conditions.

  18. Hydrogen Technologies Safety Guide

    SciTech Connect

    Rivkin, C.; Burgess, R.; Buttner, W.

    2015-01-01

    The purpose of this guide is to provide basic background information on hydrogen technologies. It is intended to provide project developers, code officials, and other interested parties the background information to be able to put hydrogen safety in context. For example, code officials reviewing permit applications for hydrogen projects will get an understanding of the industrial history of hydrogen, basic safety concerns, and safety requirements.

  19. Cryogenic hydrogen-induced air-liquefaction technologies

    NASA Technical Reports Server (NTRS)

    Escher, William J. D.

    1990-01-01

    Extensive use of a special advanced airbreathing propulsion archives data base, as well as direct contacts with individuals who were active in the field in previous years, a technical assessment of cryogenic hydrogen induced air liquefaction, as a prospective onboard aerospace vehicle process, was performed and documented in 1986. The resulting assessment report is summarized. Technical findings relating the status of air liquefaction technology are presented both as a singular technical area, and also as that of a cluster of collateral technical areas including: Compact lightweight cryogenic heat exchangers; Heat exchanger atmospheric constituents fouling alleviation; Para/ortho hydrogen shift conversion catalysts; Hydrogen turbine expanders, cryogenic air compressors and liquid air pumps; Hydrogen recycling using slush hydrogen as heat sinks; Liquid hydrogen/liquid air rocket type combustion devices; Air Collection and Enrichment System (ACES); and Technically related engine concepts.

  20. The effects of hydrogen in sealed electrical contacts

    NASA Astrophysics Data System (ADS)

    Schubert, Rudolf; Gray, Eoin W.

    1985-12-01

    Hydrogen has been an integral atmospheric component of sealed electrical contacts for decades because of its effect on reliability. It is well known that hydrogen is a needed component to prevent high contact resistance due to carbon-spot formation. This hydrogen benefit has been attributed to hydrogenation of hydrocarbons (HC), enhanced volatilization of previously deposited carbon, enhanced catalytic activity, and thermal cooling. By a variety of physical and chemical laboratory techniques, this paper shows that the hydrogen is not itself directly active. However, some of the hydrogen is converted to water during the glass sealing process. It is this water which plays the active role in the process of quenching carbon formation from hydrocarbon impurities and also acts as a diluent of HC's adsorbed on the contact surface and in the arcing volume. This limits the carbon accumulation on the contacts and increases lifetime reliability.

  1. How primitive are the gases in Titan's atmosphere?

    NASA Astrophysics Data System (ADS)

    Owen, T.

    The abundance of deuterium in Titan's methane is studied to better understand the preaccretion characteristics of the atmospheric gases. It is postulated that there are at least two distinct reservoirs of D in the outer solar system. The dominant reservoir is the D found in warm hydrogen gas which can equilibrate with other hydrogen compounds, and the second reservoir consists of the hydrogen trapped in cold compounds that never became warm enough to equilibrate with the hydrogen. It is suggested that the enrichment of D in the methane on Titan is a result of processes that took place in the interstellar medium before the solar system was formed.

  2. Sensitive hydrogen leak detector

    DOEpatents

    Myneni, Ganapati Rao

    1999-01-01

    A sensitive hydrogen leak detector system using passivation of a stainless steel vacuum chamber for low hydrogen outgassing, a high compression ratio vacuum system, a getter operating at 77.5 K and a residual gas analyzer as a quantitative hydrogen sensor.

  3. Purification of Hydrogen

    DOEpatents

    Newton, A S

    1950-12-05

    Disclosed is a process for purifying hydrogen containing various gaseous impurities by passing the hydrogen over a large surface of uranium metal at a temperature above the decomposition temperature of uranium hydride, and below the decomposition temperature of the compounds formed by the combination of the uranium with the impurities in the hydrogen.

  4. N Reactor hydrogen control

    SciTech Connect

    Shuford, D.H.; Kripps, L.J.

    1988-08-01

    Following the accident at the Chernobyl nuclear power reactor in the Soviet Union, a number of reviews were conducted of the N Reactor. Hydrogen generation during postulates severe accidents and the possibility of resulting hydrogen deflagrations/detonations that could affect confinement integrity were issues raised in several reviews, along with recommendations for adding hydrogen mitigation features. To respond to these reviews, an N Reactor Safety Enhancement Program and a subsequent Accelerated Safety Enhancement Program were initiated to address all post-Chernobyl N Reactor review findings. The Safety Enhancement Program and Accelerated Safety Enhancement Program efforts involving hydrogen control included the following: Calculate the potential hydrogen source for a range of severe accidents at the N Reactor to establish an acceptable design basis for the hydrogen mitigation system; Analyze the N Reactor confinement hydrogen mixing capability to identify areas of concern and to the verify effectiveness of the hydrogen mitigation system; Select, design, and construct a hydrogen mitigation system to enhance the N Reactor capability to accommodate possible hydrogen generation from postulated severe accidents; Provide post-accident hydrogen monitoring as an operator aid in assessing confinement conditions. In additions, it was necessary to verify that incorporation of the hydrogen mitigation system had no adverse impact N Reactor safety (e.g., radiological consequence analyses). 77 refs., 25 figs., 10 tabs.

  5. Liquid metal hydrogen barriers

    DOEpatents

    Grover, George M.; Frank, Thurman G.; Keddy, Edward S.

    1976-01-01

    Hydrogen barriers which comprise liquid metals in which the solubility of hydrogen is low and which have good thermal conductivities at operating temperatures of interest. Such barriers are useful in nuclear fuel elements containing a metal hydride moderator which has a substantial hydrogen dissociation pressure at reactor operating temperatures.

  6. Sensitive hydrogen leak detector

    DOEpatents

    Myneni, G.R.

    1999-08-03

    A sensitive hydrogen leak detector system is described which uses passivation of a stainless steel vacuum chamber for low hydrogen outgassing, a high compression ratio vacuum system, a getter operating at 77.5 K and a residual gas analyzer as a quantitative hydrogen sensor. 1 fig.

  7. Flash hydrogenation of coal

    DOEpatents

    Manowitz, Bernard; Steinberg, Meyer; Sheehan, Thomas V.; Winsche, Warren E.; Raseman, Chad J.

    1976-01-01

    A process for the hydrogenation of coal comprising the contacting of powdered coal with hydrogen in a rotating fluidized bed reactor. A rotating fluidized bed reactor suitable for use in this process is also disclosed. The coal residence time in the reactor is limited to less than 5 seconds while the hydrogen contact time is not in excess of 0.2 seconds.

  8. Chemical stratification in white dwarf atmospheres and envelopes

    NASA Technical Reports Server (NTRS)

    Koester, D.

    1989-01-01

    Theoretical arguments supporting a new mechanism maintaining a homogeneously mixed composition in white dwarf atmospheres with traces of helium are presented. Diffusion time scales, meridional circulation, mass loss, accretion of interstellar matter, convection, and radiative levitation are discussed. Theoretically, layered envelopes, with hydrogen on top of helium and an abundance profile in the transition layer determined by diffusion equilibrium, are expected. In cases with observed helium and hydrogen in the atmosphere this means that the total hydrogen mass must be very small. The empirical evidence for such atmospheres are assessed, using a new grid of model atmospheres with stratified element abundances and applying it to typical mixed abundance cases at the hot end of the white dwarf temperature sequence.

  9. Activatino of Erbium Films for Hydrogen Storage

    SciTech Connect

    M Brumbach; j Ohlhausen; K Zavadil; C Snow; J Woicik

    2011-12-31

    Hydriding of metals can be routinely performed at high temperature in a rich hydrogen atmosphere. Prior to the hydrogen loading process, a thermal activation procedure is required to promote facile hydrogen sorption into the metal. Despite the wide spread utilization of this activation procedure, little is known about the chemical and electronic changes that occur during activation and how this thermal pretreatment leads to increased rates of hydrogen uptake. This study utilized variable kinetic energy X-ray photoelectron spectroscopy to interrogate the changes during in situ thermal annealing of erbium films, with results confirmed by time-of-flight secondary ion mass spectrometry and low energy ion scattering. Activation can be identified by a large increase in photoemission between the valence band edge and the Fermi level and appears to occur over a two stage process. The first stage involves desorption of contaminants and recrystallization of the oxide, initially impeding hydrogen loading. Further heating overcomes the first stage and leads to degradation of the passive surface oxide leading to a bulk film more accessible for hydrogen loading.

  10. Nanoplasmonic hydrogen sensing

    NASA Astrophysics Data System (ADS)

    Wadell, Carl; Syrenova, Svetlana; Langhammer, Christoph

    2014-09-01

    In this review we discuss the evolution of surface plasmon resonance and localized surface plasmon resonance based hydrogen sensors. We put particular focus on how they are used to study metal-hydrogen interactions at the nanoscale, both at the ensemble and the single nanoparticle level. Such efforts are motivated by a fundamental interest in understanding the role of nanosizing on metal hydride formation processes. However, nanoplasmonic hydrogen sensors are not only of academic interest but may also find more practical use as all-optical gas detectors in industrial and medical applications, as well in a future hydrogen economy, where hydrogen is used as a carbon free energy carrier.

  11. Heated-Atmosphere Airship for the Titan Environment: Thermal Analysis

    NASA Technical Reports Server (NTRS)

    Heller, R. S.; Landis, G. A.; Hepp, A. F.; Colozza, A. J.

    2012-01-01

    Future exploration of Saturn's moon Titan can be carried out by airships. Several lighter-than-atmosphere gas airships and passive drifting heated-atmosphere balloon designs have been studied, but a heated-atmosphere airship could combine the best characteristics of both. This work analyses the thermal design of such a heated-atmosphere vehicle, and compares the result with a lighter-than-atmosphere (hydrogen) airship design. A design tool was created to enable iteration through different design parameters of a heated-atmosphere airship (diameter, number of layers, and insulating gas pocket thicknesses) and evaluate the feasibility of the resulting airship. A baseline heated-atmosphere airship was designed to have a diameter of 6 m (outer diameter of 6.2 m), three-layers of material, and an insulating gas pocket thickness of 0.05 m between each layer. The heated-atmosphere airship has a mass of 161.9 kg. A similar mission making use of a hydrogen-filled airship would require a diameter of 4.3 m and a mass of about 200 kg. For a long-duration mission, the heated-atmosphere airship appears better suited. However, for a mission lifetime under 180 days, the less complex hydrogen airship would likely be a better option.

  12. Electrochemical Measurement of Atmospheric Corrosion

    NASA Technical Reports Server (NTRS)

    DeArmond, Anna H.; Davis, Dennis D.; Beeson, Harold D.

    1999-01-01

    Corrosion of Shuttle thruster components in atmospheres containing high concentrations of nitrogen tetroxide (NTO) and water is an important issue in ground operations of bipropellant systems in humid locations. Measurements of the corrosivities of NTO-containing atmospheres and the responses of different materials to these atmospheres have been accomplished using an electrochemical sensor. The sensor is composed of alternating aluminum/titanium strips separated by thin insulating layers. Under high humidity conditions a thin film of water covers the surface of the sensor. Added NTO vapor reacts with the water film to form a conductive medium and establishes a galvanic cell. The current from this cell can be integrated with respect to time and related to the corrosion activity. The surface layer formed from humid air/NTO reacts in the same way as an aqueous solution of nitric acid. Nitric acid is generally considered an important agent in NTO corrosion situations. The aluminum/titanium sensor is unresponsive to dry air, responds slightly to humid air (> 75% RH), and responds strongly to the combination of humid air and NTO. The sensor response is a power function (n = 2) of the NTO concentration. The sensor does not respond to NTO in dry air. The response of other materials in this type of sensor is related to position of the material in a galvanic series in aqueous nitric acid. The concept and operation of this electrochemical corrosion measurement is being applied to other corrosive atmospheric contaminants such as hydrogen chloride, hydrogen fluoride, sulfur dioxide, and acidic aerosols.

  13. Unxpected Time-Variability of Martian Hydrogen Loss

    NASA Astrophysics Data System (ADS)

    Chaffin, Michael S.; Yves-Chaufray, J.; Stewart, I.; Montmessin, F.; Schneider, N.

    2013-10-01

    Mars today is much drier than the Earth, though they likely began with similar relative amounts of water. One potential cause for this discrepancy is hydrogen loss from surface water to space, which may have removed one-third of Mars' initial water. For forty years, this water loss has been assumed to be indirect and constant: the result of molecular hydrogen produced at the surface being transported into the ionosphere, where it is partially converted into atomic hydrogen that subsequently escapes. The centuries-long lifetime of molecular hydrogen in the atmosphere of Mars supposedly prevents hydrogen loss from varying significantly year-to-year or across the solar cycle. In contradiction of this model, we present strong evidence of seasonal or dust-driven variation in the escape of hydrogen from Mars. We analyze 121.6 nm (hydrogen Lyman-alpha) airglow observations made by the ultraviolet spectrometer SPICAM on ESA's Mars Express spacecraft over the second half of 2007, observing a factor of two decrease in the brightness of the exosphere of Mars at this wavelength. We find a near-exponential decrease in the escape rate of hydrogen over the study period, demonstrating an order-of-magnitude decline in hydrogen escape flux. These results are incompatible with the current model of molecular hydrogen as the carrier of Martian water from surface to ionosphere, and suggest that water escape may proceed directly through injection of water vapor into the upper atmosphere at concentrations greater than any previously observed. This scenario potentially octuples previous estimates of the total amount of water lost to space over Martian history, exacerbating the problem of non-thermal oxygen loss (with implications for the redox state of the atmosphere and surface), and indicates that brief periods of enhanced escape may dominate Martian water loss.

  14. Atmospheric electricity

    NASA Technical Reports Server (NTRS)

    1987-01-01

    In the last three years the focus was on the information contained in the lightning measurement, which is independent of other meteorological measurements that can be made from space. The characteristics of lightning activity in mesoscale convective systems were quantified. A strong relationship was found between lightning activity and surface rainfall. It is shown that lightning provides a precursor signature for wet microbursts (the strong downdrafts that produce windshears hazardous to aircraft) and that the lightning signature is a direct consequence of storm evolution. The Universities Space Research Association (USRA) collaborated with NASA scientists in the preliminary analysis and scientific justification for the design and deployment of an optical instrument which can detect lightning from geostationary orbit. Science proposals for the NASA mesoscale science program and for the Tethered Satellite System were reviewed. The weather forecasting research and unmanned space vehicles. Software was written to ingest and analyze the lightning ground strike data on the MSFC McIDAS system. The capabilities which were developed have a wide application to a number of problems associated with the operational impacts of electrical discharge within the atmosphere.

  15. An In-situ Tensile Test Apparatus for Polymers in High Pressure Hydrogen

    SciTech Connect

    Alvine, Kyle J.; Kafentzis, Tyler A.; Pitman, Stan G.; Johnson, Kenneth I.; Skorski, Daniel C.; Tucker, Joseph C.; Roosendaal, Timothy J.; Dahl, Michael E.

    2014-10-10

    Degradation of material properties by high-pressure hydrogen is an important factor in determining the safety and reliability of materials used in high-pressure hydrogen storage and delivery. Hydrogen damage mechanisms have a time dependence that is linked to hydrogen outgassing after exposure to the hydrogen atmosphere that makes ex-situ measurements of mechanical properties problematic. Designing in-situ measurement instruments for high-pressure hydrogen is challenging due to known hydrogen incompatibility with many metals and standard high-power motor materials like Nd. Here we detail the design and operation of a solenoid based in-situ tensile tester under high-pressure hydrogen environments up to 5,000 psi. Modulus data from high-density polyethylene (HDPE) samples tested under high-pressure hydrogen are also reported as compared to baseline measurements taken in air.

  16. An in situ tensile test apparatus for polymers in high pressure hydrogen

    SciTech Connect

    Alvine, K. J. Kafentzis, T. A.; Pitman, S. G.; Johnson, K. I.; Skorski, D.; Tucker, J. C.; Roosendaal, T. J.; Dahl, M. E.

    2014-10-15

    Degradation of material properties by high-pressure hydrogen is an important factor in determining the safety and reliability of materials used in high-pressure hydrogen storage and delivery. Hydrogen damage mechanisms have a time dependence that is linked to hydrogen outgassing after exposure to the hydrogen atmosphere that makes ex situ measurements of mechanical properties problematic. Designing in situ measurement instruments for high-pressure hydrogen is challenging due to known hydrogen incompatibility with many metals and standard high-power motor materials such as Nd. Here we detail the design and operation of a solenoid based in situ tensile tester under high-pressure hydrogen environments up to 42 MPa (6000 psi). Modulus data from high-density polyethylene samples tested under high-pressure hydrogen at 35 MPa (5000 psi) are also reported as compared to baseline measurements taken in air.

  17. Safety aspects of large-scale combustion of hydrogen

    SciTech Connect

    Edeskuty, F.J.; Haugh, J.J.; Thompson, R.T.

    1986-01-01

    Recent hydrogen-safety investigations have studied the possible large-scale effects from phenomena such as the accumulation of combustible hydrogen-air mixtures in large, confined volumes. Of particular interest are safe methods for the disposal of the hydrogen and the pressures which can arise from its confined combustion. Consequently, tests of the confined combustion of hydrogen-air mixtures were conducted in a 2100 m/sup 3/ volume. These tests show that continuous combustion, as the hydrogen is generated, is a safe method for its disposal. It also has been seen that, for hydrogen concentrations up to 13 vol %, it is possible to predict maximum pressures that can occur upon ignition of premixed hydrogen-air atmospheres. In addition information has been obtained concerning the survivability of the equipment that is needed to recover from an accident involving hydrogen combustion. An accident that involved the inadvertent mixing of hydrogen and oxygen gases in a tube trailer gave evidence that under the proper conditions hydrogen combustion can transit to a detonation. If detonation occurs the pressures which can be experienced are much higher although short in duration.

  18. Thermospheric hydrogen response to increases in greenhouse gases

    NASA Astrophysics Data System (ADS)

    Nossal, S. M.; Qian, L.; Solomon, S. C.; Burns, A. G.; Wang, W.

    2016-04-01

    We investigated thermospheric hydrogen response to increase in greenhouse gases and the dependence of this response to solar activity, using a global mean version of the National Center for Atmospheric Research Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model. We separately doubled carbon dioxide (CO2) and methane (CH4) to study the influence of temperature and changes to source species for hydrogen. Our results indicate that both CO2 cooling and CH4 changes to the source species for hydrogen lead to predicted increases in the upper thermospheric hydrogen density. At 400 km, hydrogen increases ~30% under solar maximum and ~25% under solar minimum responding to doubling of CH4, indicating that hydrogen response to the source variation due to CH4 increase is relatively independent of solar activity. On the other hand, hydrogen response to doubling of CO2 highly depends on solar activity. At 400 km, doubling of CO2 results in an ~7% hydrogen increase at solar maximum, whereas it is ~25% at solar minimum. Consequently, at solar maximum, the predicted ~40% increase in atomic hydrogen in the upper thermosphere is primarily due to the source variation as a result of doubling of CH4, whereas at solar minimum, both cooling due to doubling of CO2 and the source variation due to doubling of CH4 have commensurate effects, resulting in an approximate 50% increase in the modeled upper thermospheric hydrogen.

  19. Process and apparatus for coal hydrogenation

    DOEpatents

    Ruether, John A.; Simpson, Theodore B.

    1991-01-01

    In a coal liquefaction process an aqueous slurry of coal is prepared containing a dissolved liquefaction catalyst. A small quantity of oil is added to the slurry and then coal-oil agglomerates are prepared by agitation of the slurry at atmospheric pressure. The resulting mixture is drained of excess water and dried at atmospheric pressure leaving catalyst deposited on the agglomerates. The agglomerates then are fed to an extrusion device where they are formed into a continuous ribbon of extrudate and fed into a hydrogenation reactor at elevated pressure and temperature. The catalytic hydrogenation converts the extrudate primarily to liquid hydrocarbons in the reactor. The liquid drained in recovering the agglomerates is recycled.

  20. Hydrogen storage methods.

    PubMed

    Züttel, Andreas

    2004-04-01

    Hydrogen exhibits the highest heating value per mass of all chemical fuels. Furthermore, hydrogen is regenerative and environmentally friendly. There are two reasons why hydrogen is not the major fuel of today's energy consumption. First of all, hydrogen is just an energy carrier. And, although it is the most abundant element in the universe, it has to be produced, since on earth it only occurs in the form of water and hydrocarbons. This implies that we have to pay for the energy, which results in a difficult economic dilemma because ever since the industrial revolution we have become used to consuming energy for free. The second difficulty with hydrogen as an energy carrier is its low critical temperature of 33 K (i.e. hydrogen is a gas at ambient temperature). For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage material is crucial. Hydrogen can be stored using six different methods and phenomena: (1) high-pressure gas cylinders (up to 800 bar), (2) liquid hydrogen in cryogenic tanks (at 21 K), (3) adsorbed hydrogen on materials with a large specific surface area (at T<100 K), (4) absorbed on interstitial sites in a host metal (at ambient pressure and temperature), (5) chemically bonded in covalent and ionic compounds (at ambient pressure), or (6) through oxidation of reactive metals, e.g. Li, Na, Mg, Al, Zn with water. The most common storage systems are high-pressure gas cylinders with a maximum pressure of 20 MPa (200 bar). New lightweight composite cylinders have been developed which are able to withstand pressures up to 80 MPa (800 bar) and therefore the hydrogen gas can reach a volumetric density of 36 kg.m(-3), approximately half as much as in its liquid state. Liquid hydrogen is stored in cryogenic tanks at 21.2 K and ambient pressure. Due to the low critical temperature of hydrogen (33 K), liquid hydrogen can only be stored in open systems. The volumetric density of liquid hydrogen

  1. Hydrogen storage methods

    NASA Astrophysics Data System (ADS)

    Züttel, Andreas

    Hydrogen exhibits the highest heating value per mass of all chemical fuels. Furthermore, hydrogen is regenerative and environmentally friendly. There are two reasons why hydrogen is not the major fuel of today's energy consumption. First of all, hydrogen is just an energy carrier. And, although it is the most abundant element in the universe, it has to be produced, since on earth it only occurs in the form of water and hydrocarbons. This implies that we have to pay for the energy, which results in a difficult economic dilemma because ever since the industrial revolution we have become used to consuming energy for free. The second difficulty with hydrogen as an energy carrier is its low critical temperature of 33 K (i.e. hydrogen is a gas at ambient temperature). For mobile and in many cases also for stationary applications the volumetric and gravimetric density of hydrogen in a storage material is crucial. Hydrogen can be stored using six different methods and phenomena: (1) high-pressure gas cylinders (up to 800 bar), (2) liquid hydrogen in cryogenic tanks (at 21 K), (3) adsorbed hydrogen on materials with a large specific surface area (at T<100 K), (4) absorbed on interstitial sites in a host metal (at ambient pressure and temperature), (5) chemically bonded in covalent and ionic compounds (at ambient pressure), or (6) through oxidation of reactive metals, e.g. Li, Na, Mg, Al, Zn with water. The most common storage systems are high-pressure gas cylinders with a maximum pressure of 20 MPa (200 bar). New lightweight composite cylinders have been developed which are able to withstand pressures up to 80 MPa (800 bar) and therefore the hydrogen gas can reach a volumetric density of 36 kg.m-3, approximately half as much as in its liquid state. Liquid hydrogen is stored in cryogenic tanks at 21.2 K and ambient pressure. Due to the low critical temperature of hydrogen (33 K), liquid hydrogen can only be stored in open systems. The volumetric density of liquid hydrogen is

  2. Wavelength-codified fiber laser hydrogen detector

    NASA Astrophysics Data System (ADS)

    Ortigosa-Blanch, A.; Díez, A.; González-Segura, A.; Cruz, J. L.; Andrés, M. V.

    2005-11-01

    We report a scheme for an optical hydrogen detector that codifies the information in wavelength. The system is based on an erbium-doped fiber laser with two coupled cavities and a Palladium-coated tapered fiber within one of the laser cavities. The tapered fiber acts as the hydrogen-sensing element. When the sensing element is exposed to a hydrogen atmosphere, its attenuation decreases changing the cavity losses. This change leads the system to switch lasing from the wavelength of the auxiliary cavity to the characteristic wavelength of the cavity which contains the sensing element. The detection level can be shifted by adjusting the reflective elements of the cavity containing the sensing element.

  3. White dwarf stars with carbon atmospheres.

    PubMed

    Dufour, P; Liebert, J; Fontaine, G; Behara, N

    2007-11-22

    White dwarfs represent the endpoint of stellar evolution for stars with initial masses between approximately 0.07 and 8-10, where is the mass of the Sun (more massive stars end their life as either black holes or neutron stars). The theory of stellar evolution predicts that the majority of white dwarfs have a core made of carbon and oxygen, which itself is surrounded by a helium layer and, for approximately 80 per cent of known white dwarfs, by an additional hydrogen layer. All white dwarfs therefore have been traditionally found to belong to one of two categories: those with a hydrogen-rich atmosphere (the DA spectral type) and those with a helium-rich atmosphere (the non-DAs). Here we report the discovery of several white dwarfs with atmospheres primarily composed of carbon, with little or no trace of hydrogen or helium. Our analysis shows that the atmospheric parameters found for these stars do not fit satisfactorily in any of the currently known theories of post-asymptotic giant branch evolution, although these objects might be the cooler counterpart of the unique and extensively studied PG 1159 star H1504+65 (refs 4-7). These stars, together with H1504+65, might accordingly form a new evolutionary sequence that follows the asymptotic giant branch.

  4. Hydrogen Storage in the Carbon Dioxide - Formic Acid Cycle.

    PubMed

    Fink, Cornel; Montandon-Clerc, Mickael; Laurenczy, Gabor

    2015-01-01

    This year Mankind will release about 39 Gt carbon dioxide into the earth's atmosphere, where it acts as a greenhouse gas. The chemical transformation of carbon dioxide into useful products becomes increasingly important, as the CO(2) concentration in the atmosphere has reached 400 ppm. One approach to contribute to the decrease of this hazardous emission is to recycle CO(2), for example reducing it to formic acid. The hydrogenation of CO(2) can be achieved with a series of catalysts under basic and acidic conditions, in wide variety of solvents. To realize a hydrogen-based charge-discharge device ('hydrogen battery'), one also needs efficient catalysts for the reverse reaction, the dehydrogenation of formic acid. Despite of the fact that the overwhelming majority of these reactions are carried out using precious metals-based catalysts (mainly Ru), we review here developments for catalytic hydrogen evolution from formic acid with iron-based complexes.

  5. Hydrogen Filling Station

    SciTech Connect

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. The Freedom CAR and Freedom FUEL initiatives emphasize the importance of hydrogen as a future transportation fuel. Presently, Las Vegas has one hydrogen fueling station powered by natural gas. However, the use of traditional sources of energy to produce hydrogen does not maximize the benefit. The hydrogen fueling station developed under this grant used electrolysis units and solar energy to produce hydrogen fuel. Water and electricity are furnished to the unit and the output is hydrogen and oxygen. Three vehicles were converted to utilize the hydrogen produced at the station. The vehicles were all equipped with different types of technologies. The vehicles were used in the day-to-day operation of the Las Vegas Valley Water District and monitoring was performed on efficiency, reliability and maintenance requirements. The research and demonstration utilized for the reconfiguration of these vehicles could lead to new technologies in vehicle development that could make hydrogen-fueled vehicles more cost effective, economical, efficient and more widely used. In order to advance the development of a hydrogen future in Southern Nevada, project partners recognized a need to bring various entities involved in hydrogen development and deployment together as a means of sharing knowledge and eliminating duplication of efforts. A road-mapping session was held in Las Vegas in June 2006. The Nevada State Energy Office, representatives from DOE, DOE contractors and LANL, NETL, NREL were present. Leadership from the National hydrogen Association Board of Directors also attended. As a result of this session, a roadmap for hydrogen development was created. This roadmap has the ability to become a tool for use by other road-mapping efforts in the hydrogen community. It could also become a standard template for other states or even countries to approach planning for a hydrogen

  6. Renewable hydrogen production for fossil fuel processing

    SciTech Connect

    Greenbaum, E.; Lee, J.W.; Tevault, C.V.

    1995-06-01

    In the fundamental biological process of photosynthesis, atmospheric carbon dioxide is reduced to carbohydrate using water as the source of electrons with simultaneous evolution of molecular oxygen: H{sub 2}O + CO{sub 2} + light {yields} O{sub 2} + (CH{sub 2}O). It is well established that two light reactions, Photosystems I and II (PSI and PSII) working in series, are required to perform oxygenic photosynthesis. Experimental data supporting the two-light reaction model are based on the quantum requirement for complete photosynthesis, spectroscopy, and direct biochemical analysis. Some algae also have the capability to evolve molecular hydrogen in a reaction energized by the light reactions of photosynthesis. This process, now known as biophotolysis, can use water as the electron donor and lead to simultaneous evolution of molecular hydrogen and oxygen. In green algae, hydrogen evolution requires prior incubation under anaerobic conditions. Atmospheric oxygen inhibits hydrogen evolution and also represses the synthesis of hydrogenase enzyme. CO{sub 2} fixation competes with proton reduction for electrons relased from the photosystems. Interest in biophotolysis arises from both the questions that it raises concerning photosynthesis and its potential practical application as a process for converting solar energy to a non-carbon-based fuel. Prior data supported the requirement for both Photosystem I and Photosystem II in spanning the energy gap necessary for biophotolysis of water to oxygen and hydrogen. In this paper we report the at PSII alone is capable of driving sustained simultaneous photoevolution of molecular hydrogen and oxygen in an anaerobically adapted PSI-deficient strain of Chlamydomonas reinhardtii, mutant B4, and that CO{sub 2} competes as an electron acceptor.

  7. Hydrogen energy systems studies

    SciTech Connect

    Ogden, J.M.; Steinbugler, M.; Kreutz, T.

    1998-08-01

    In this progress report (covering the period May 1997--May 1998), the authors summarize results from ongoing technical and economic assessments of hydrogen energy systems. Generally, the goal of their research is to illuminate possible pathways leading from present hydrogen markets and technologies toward wide scale use of hydrogen as an energy carrier, highlighting important technologies for RD and D. Over the past year they worked on three projects. From May 1997--November 1997, the authors completed an assessment of hydrogen as a fuel for fuel cell vehicles, as compared to methanol and gasoline. Two other studies were begun in November 1997 and are scheduled for completion in September 1998. The authors are carrying out an assessment of potential supplies and demands for hydrogen energy in the New York City/New Jersey area. The goal of this study is to provide useful data and suggest possible implementation strategies for the New York City/ New Jersey area, as the Hydrogen Program plans demonstrations of hydrogen vehicles and refueling infrastructure. The authors are assessing the implications of CO{sub 2} sequestration for hydrogen energy systems. The goals of this work are (a) to understand the implications of CO{sub 2} sequestration for hydrogen energy system design; (b) to understand the conditions under which CO{sub 2} sequestration might become economically viable; and (c) to understand design issues for future low-CO{sub 2} emitting hydrogen energy systems based on fossil fuels.

  8. Ultrafine hydrogen storage powders

    DOEpatents

    Anderson, Iver E.; Ellis, Timothy W.; Pecharsky, Vitalij K.; Ting, Jason; Terpstra, Robert; Bowman, Robert C.; Witham, Charles K.; Fultz, Brent T.; Bugga, Ratnakumar V.

    2000-06-13

    A method of making hydrogen storage powder resistant to fracture in service involves forming a melt having the appropriate composition for the hydrogen storage material, such, for example, LaNi.sub.5 and other AB.sub.5 type materials and AB.sub.5+x materials, where x is from about -2.5 to about +2.5, including x=0, and the melt is gas atomized under conditions of melt temperature and atomizing gas pressure to form generally spherical powder particles. The hydrogen storage powder exhibits improved chemcial homogeneity as a result of rapid solidfication from the melt and small particle size that is more resistant to microcracking during hydrogen absorption/desorption cycling. A hydrogen storage component, such as an electrode for a battery or electrochemical fuel cell, made from the gas atomized hydrogen storage material is resistant to hydrogen degradation upon hydrogen absorption/desorption that occurs for example, during charging/discharging of a battery. Such hydrogen storage components can be made by consolidating and optionally sintering the gas atomized hydrogen storage powder or alternately by shaping the gas atomized powder and a suitable binder to a desired configuration in a mold or die.

  9. Hydrogen interactions with metals

    NASA Technical Reports Server (NTRS)

    Mclellan, R. B.; Harkins, C. G.

    1975-01-01

    Review of the literature on the nature and extent of hydrogen interactions with metals and the role of hydrogen in metal failure. The classification of hydrogen-containing systems is discussed, including such categories as covalent hydrides, volatile hydrides, polymeric hydrides, and transition metal hydride complexes. The use of electronegativity as a correlating parameter in determining hydride type is evaluated. A detailed study is made of the thermodynamics of metal-hydrogen systems, touching upon such aspects as hydrogen solubility, the positions occupied by hydrogen atoms within the solvent metal lattice, the derivation of thermodynamic functions of solid solutions from solubility data, and the construction of statistical models for hydrogen-metal solutions. A number of theories of hydrogen-metal bonding are reviewed, including the rigid-band model, the screened-proton model, and an approach employing the augmented plane wave method to solve the one-electron energy band problem. Finally, the mechanism of hydrogen embrittlement is investigated on the basis of literature data concerning stress effects and the kinetics of hydrogen transport to critical sites.

  10. The chemistry of Venus' atmosphere

    NASA Technical Reports Server (NTRS)

    Sze, N. D.; Smith, W. H.

    1978-01-01

    A model for the Venus atmosphere involving photochemistry of oxygen, hydrogen, chlorine and sulfur species is presented. Sulfur reaction schemes and hydrogen and chlorine reaction schemes were included. The impact of sulfur on the oxygen budget and the subsequent production of H2SO4 molecules for the Venus cloud deck were explored. A major new reaction scheme for production of H2SO4 molecules involving sulfur and oxygen chemistry was established shown to dominate over the odd hydrogen scheme proposed earlier. The efficiency of the scheme in formation of H2SO4 is only about 50%, with the remaining sulfur residing in SO2 molecules. The calculated downward flux of H2SO4 may be sufficient to maintain a steady state sulfuric acid cloud if the resident time of H2SO4 droplets in the cloud is as long as a few years. If however, the resident time is half a year or shorter, additional chemistry capable of more efficient conversion of SO2 to SO3 is required.

  11. Potential environmental impact of a hydrogen economy on the stratosphere.

    PubMed

    Tromp, Tracey K; Shia, Run-Lie; Allen, Mark; Eiler, John M; Yung, Y L

    2003-06-13

    The widespread use of hydrogen fuel cells could have hitherto unknown environmental impacts due to unintended emissions of molecular hydrogen, including an increase in the abundance of water vapor in the stratosphere (plausibly by as much as approximately 1 part per million by volume). This would cause stratospheric cooling, enhancement of the heterogeneous chemistry that destroys ozone, an increase in noctilucent clouds, and changes in tropospheric chemistry and atmosphere-biosphere interactions.

  12. Prediction and assignment of the FIR spectrum of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Helminger, P.; Messer, J. K.; De Lucia, F. C.; Bowman, W. C.

    1984-01-01

    Millimeter and submillimeter microwave studies are used to predict and assign the FIR rotational-torsional spectrum of hydrogen peroxide. Special attention is given to the strong Q-branch features that have recently been used by Traub and Chance to place an upper limit on the atmospheric abundance of hydrogen peroxide. In addition, 67 new transitions are reported in the 400-1000 GHz region.

  13. HELIUM ATMOSPHERES ON WARM NEPTUNE- AND SUB-NEPTUNE-SIZED EXOPLANETS AND APPLICATIONS TO GJ 436b

    SciTech Connect

    Hu, Renyu; Yung, Yuk L.; Seager, Sara

    2015-07-01

    Warm Neptune- and sub-Neptune-sized exoplanets in orbits smaller than Mercury’s are thought to have experienced extensive atmospheric evolution. Here we propose that a potential outcome of this atmospheric evolution is the formation of helium-dominated atmospheres. The hydrodynamic escape rates of Neptune- and sub-Neptune-sized exoplanets are comparable to the diffusion-limited escape rate of hydrogen, and therefore the escape is heavily affected by diffusive separation between hydrogen and helium. A helium atmosphere can thus be formed—from a primordial hydrogen–helium atmosphere—via atmospheric hydrodynamic escape from the planet. The helium atmosphere has very different abundances of major carbon and oxygen species from those of a hydrogen atmosphere, leading to distinctive transmission and thermal emission spectral features. In particular, the hypothesis of a helium-dominated atmosphere can explain the thermal emission spectrum of GJ 436b, a warm Neptune-sized exoplanet, while also being consistent with the transmission spectrum. This model atmosphere contains trace amounts of hydrogen, carbon, and oxygen, with the predominance of CO over CH{sub 4} as the main form of carbon. With our atmospheric evolution model, we find that if the mass of the initial atmosphere envelope is 10{sup −3} planetary mass, hydrodynamic escape can reduce the hydrogen abundance in the atmosphere by several orders of magnitude in ∼10 billion years. Observations of exoplanet transits may thus detect signatures of helium atmospheres and probe the evolutionary history of small exoplanets.

  14. Analysis of hydrogen isotope mixtures

    DOEpatents

    Villa-Aleman, Eliel

    1994-01-01

    An apparatus and method for determining the concentrations of hydrogen isotopes in a sample. Hydrogen in the sample is separated from other elements using a filter selectively permeable to hydrogen. Then the hydrogen is condensed onto a cold finger or cryopump. The cold finger is rotated as pulsed laser energy vaporizes a portion of the condensed hydrogen, forming a packet of molecular hydrogen. The desorbed hydrogen is ionized and admitted into a mass spectrometer for analysis.

  15. Photochemically driven collapse of Titan's atmosphere.

    PubMed

    Lorenz, R D; McKay, C P; Lunine, J I

    1997-01-31

    Saturn's giant moon Titan has a thick (1.5 bar) nitrogen atmosphere, which has a temperature structure that is controlled by the absorption of solar and thermal radiation by methane, hydrogen, and organic aerosols into which methane is irreversibly converted by photolysis. Previous studies of Titan's climate evolution have been done with the assumption that the methane abundance was maintained against photolytic depletion throughout Titan's history, either by continuous supply from the interior or by buffering by a surface or near surface reservoir. Radiative-convective and radiative-saturated equilibrium models of Titan's atmosphere show that methane depletion may have allowed Titan's atmosphere to cool so that nitrogen, its main constituent, condenses onto the surface, collapsing Titan into a Triton-like frozen state with a thin atmosphere.

  16. Atmospheric evolution of the terrestrial planets

    NASA Astrophysics Data System (ADS)

    Hunten, D. M.

    1993-02-01

    The major atmospheric gases on Earth, Venus, and Mars were probably CO2, H2O, and N2. Most of the Earth's CO2 is tied up in minerals such as limestone, and Venus has lost most of its H2O, leaving the CO2 in the atmosphere. Much of Mars' atmosphere may have been eroded in impacts by large meteoroids early in solar-system history. Noble gases are very underabundant everywhere, and must have been lost during an early period: they were probably dragged along during rapid loss of massive amounts of hydrogen. The tenuous atmospheres of Mercury and the moon have lifetimes of a few days or less and must be continuously replenished from internal or external sources.

  17. Mars Molniya Orbit Atmospheric Resource Mining

    NASA Technical Reports Server (NTRS)

    Mueller, Robert P.; Braun, Robert D.; Sibille, Laurent; Sforzo, Brandon; Gonyea, Keir; Ali, Hisham

    2016-01-01

    This NIAC (NASA Advanced Innovative Concepts) work will focus on Mars and will build on previous efforts at analyzing atmospheric mining at Earth and the outer solar system. Spacecraft systems concepts will be evaluated and traded, to assess feasibility. However the study will primarily examine the architecture and associated missions to explore the closure, constraints and critical parameters through sensitivity studies. The Mars atmosphere consists of 95.5 percent CO2 gas which can be converted to methane fuel (CH4) and Oxidizer (O2) for chemical rocket propulsion, if hydrogen is transported from electrolyzed water on the Mars surface or from Earth. By using a highly elliptical Mars Molniya style orbit, the CO2 atmosphere can be scooped, ram-compressed and stored while the spacecraft dips into the Mars atmosphere at periapsis. Successive orbits result in additional scooping of CO2 gas, which also serves to aerobrake the spacecraft, resulting in a decaying Molniya orbit.

  18. The atmospheric water vapor line.

    NASA Astrophysics Data System (ADS)

    Strong, M.; Sharp, Z. D.; Gutzler, D. S.

    2008-12-01

    We have measured the hydrogen and oxygen isotope composition of atmospheric water vapor periodically across the American Southwest through most of 2007. Samples were primarily collected over Albuquerque, NM on the roof of the 3-story UNM geology building on a near-daily basis with occasional sampling in southern Arizona and southern Texas. Water vapor was captured by pumping ~60 to ~600 liters of air (amount depending on dew point) through a cold trap, producing ~1mL of water. Precipitation samples were also collected in Albuquerque throughout the year and analyzed for hydrogen and oxygen isotopic composition. Isotopic compositions of both vapor and precipitation were determined by CO2 equilibration for oxygen and chromium reduction for hydrogen, with resulting gasses analyzed on a mass spectrometer. Nearly all water vapor samples lie parallel to the Global Meteoric Water Line (GMWL) but with a deuterium excess of ~17 (δD = 8δO + 17). This is true regardless of relative humidity, dew point, location, time of day, or season. Precipitation samples fall to the right of the GMWL with a slope of ~5. Within our dataset we have identified 10 pairs of vapor and precipitation samples that were collected within 24 hours. Half of these sample pairs have values consistent with equilibrium conditions at ground temperature, while the other half are not in equilibrium at any temperature. Simple modeling of nonequilibrium fractionation processes suggests that the array of precipitation samples can be derived from the array of vapor samples by equilibrium condensation followed by partial evaporation of falling raindrops. Our data suggests that atmospheric water vapor has a relatively constant deuterium excess value regardless of moisture source, degree of rainout, and/or evapotranspiration contributions.

  19. Hydrogen Permeation Resistant Coatings

    SciTech Connect

    KORINKO, PAUL; ADAMS, THAD; CREECH, GREGGORY

    2005-06-15

    As the National Hydrogen Economy continues to develop and evolve the need for structural materials that can resist hydrogen assisted degradation will become critical. To date austenitic stainless steel materials have been shown to be mildly susceptible to hydrogen attack which results in lower mechanical and fracture strengths. As a result, hydrogen permeation barrier coatings may be applied to these ferrous alloys to retard hydrogen ingress. Hydrogen is known to be very mobile in materials of construction. In this study, the permeation resistance of bare stainless steel samples and coated stainless steel samples was tested. The permeation resistance was measured using a modular permeation rig using a pressure rise technique. The coating microstructure and permeation results will be discussed in this document as will some additional testing.

  20. Hydrogenation of carbonaceous materials

    DOEpatents

    Friedman, Joseph; Oberg, Carl L.; Russell, Larry H.

    1980-01-01

    A method for reacting pulverized coal with heated hydrogen-rich gas to form hydrocarbon liquids suitable for conversion to fuels wherein the reaction involves injection of pulverized coal entrained in a minimum amount of gas and mixing the entrained coal at ambient temperature with a separate source of heated hydrogen. In accordance with the present invention, the hydrogen is heated by reacting a small portion of the hydrogen-rich gas with oxygen in a first reaction zone to form a gas stream having a temperature in excess of about 1000.degree. C. and comprising a major amount of hydrogen and a minor amount of water vapor. The coal particles then are reacted with the hydrogen in a second reaction zone downstream of the first reaction zone. The products of reaction may be rapidly quenched as they exit the second reaction zone and are subsequently collected.

  1. The role of organic haze in the hydrogen budget on Titan

    NASA Astrophysics Data System (ADS)

    Sekine, Y.; Imanaka, H.; Lebonnois, S.; Khare, B. N.; Bakes, E. L. O.; McKay, C. P.; Sugita, S.; Matsui, T.

    In Titan's atmosphere composing of N2 and CH4 , large amounts of atomic hydrogens are produced by photochemical reactions during the formation of organic products. The fate of these reactive atomic hydrogens is critical to understand the chemical composition, climatology, and evolution of Titan's atmosphere. Theoretical models proposed that atomic hydrogen might recombine H atoms to H2 molecules via the heterogeneous reactions with the organic haze in the atmosphere. However, there have been no experimental investigations on the heterogeneous reactions. In order to investigate both the mechanisms and kinetics of the heterogeneous reactions, we irradiate atomic deuterium onto Titan tholin formed from N2 /CH4 gas mixtures. The combined analyses of the gas species and irradiated tholin indicate that the interaction mechanisms of atomic deuterium with the Titan tholin are mainly composed of two reactions; a) abstraction of hydrogen in tholin by forming HD (HD recombination) and b) addition of D atom into tholin (hydrogenation). We obtain the reaction probabilities and activation energies of HD recombination and hydrogenation under the conditions similar to Titan's atmosphere. Then, we introduce the obtained reaction probabilities into a one-dimensional photochemical model in order to assess the role of organic haze in the hydrogen budget and chemical composition of Titan's atmosphere. The calculation results show that about 60 - 70 % of atomic hydrogen formed in the stratosphere and mesosphere are consumed by the heterogeneous reactions on the surface of haze particles. Low concentration of atomic hydrogen significantly enhances the concentrations of unsaturated complex organics, such as aliphatic polymers and polycyclic aromatic compounds, which may induce efficient haze production in Titan's upper atmosphere. Our experimental and calculation results indicate that Titan haze may act as a catalyst not only to remove atomic hydrogen efficiently but also to promote the

  2. HYDROGEN ATOM THERMAL PARAMETERS.

    PubMed

    JENSEN, L H; SUNDARALINGAM, M

    1964-09-11

    Isotropic hydrogen atom thermal parameters for N,N'- hexamethylenebispropionamide have been determined. They show a definite trend and vary from approximately the same as the mean thermal parameters for atoms other than hydrogen near the center of the molecule to appreciably greater for atoms near the end. The indicated trend for this compound, along with other results, provides the basis for a possible explanation of the anomolous values that have been obtained for hydrogen atom thermal parameters.

  3. National hydrogen energy roadmap

    SciTech Connect

    None, None

    2002-11-01

    This report was unveiled by Energy Secretary Spencer Abraham in November 2002 and provides a blueprint for the coordinated, long-term, public and private efforts required for hydrogen energy development. Based on the results of the government-industry National Hydrogen Energy Roadmap Workshop, held in Washington, DC on April 2-3, 2002, it displays the development of a roadmap for America's clean energy future and outlines the key barriers and needs to achieve the hydrogen vision goals defined in

  4. Hydrogen storage container

    DOEpatents

    Wang, Jy-An John; Feng, Zhili; Zhang, Wei

    2017-02-07

    An apparatus and system is described for storing high-pressure fluids such as hydrogen. An inner tank and pre-stressed concrete pressure vessel share the structural and/or pressure load on the inner tank. The system and apparatus provide a high performance and low cost container while mitigating hydrogen embrittlement of the metal tank. System is useful for distributing hydrogen to a power grid or to a vehicle refueling station.

  5. Hydrogen rich gas generator

    NASA Technical Reports Server (NTRS)

    Houseman, J. (Inventor)

    1976-01-01

    A process and apparatus is described for producing a hydrogen rich gas by introducing a liquid hydrocarbon fuel in the form of a spray into a partial oxidation region and mixing with a mixture of steam and air that is preheated by indirect heat exchange with the formed hydrogen rich gas, igniting the hydrocarbon fuel spray mixed with the preheated mixture of steam and air within the partial oxidation region to form a hydrogen rich gas.

  6. Hydrogen energy systems studies

    SciTech Connect

    Ogden, J.M.; Steinbugler, M.; Dennis, E.

    1995-09-01

    For several years, researchers at Princeton University`s Center for Energy and Environmental Studies have carried out technical and economic assessments of hydrogen energy systems. Initially, we focussed on the long term potential of renewable hydrogen. More recently we have explored how a transition to renewable hydrogen might begin. The goal of our current work is to identify promising strategies leading from near term hydrogen markets and technologies toward eventual large scale use of renewable hydrogen as an energy carrier. Our approach has been to assess the entire hydrogen energy system from production through end-use considering technical performance, economics, infrastructure and environmental issues. This work is part of the systems analysis activity of the DOE Hydrogen Program. In this paper we first summarize the results of three tasks which were completed during the past year under NREL Contract No. XR-11265-2: in Task 1, we carried out assessments of near term options for supplying hydrogen transportation fuel from natural gas; in Task 2, we assessed the feasibility of using the existing natural gas system with hydrogen and hydrogen blends; and in Task 3, we carried out a study of PEM fuel cells for residential cogeneration applications, a market which might have less stringent cost requirements than transportation. We then give preliminary results for two other tasks which are ongoing under DOE Contract No. DE-FG04-94AL85803: In Task 1 we are assessing the technical options for low cost small scale production of hydrogen from natural gas, considering (a) steam reforming, (b) partial oxidation and (c) autothermal reforming, and in Task 2 we are assessing potential markets for hydrogen in Southern California.

  7. Hydrogen powered bus

    SciTech Connect

    2011-04-07

    Take a ride on a new type of bus, fueled by hydrogen. These hydrogen taxis are part of a Department of Energy-funded deployment of hydrogen powered vehicles and fueling infrastructure at nine federal facilities across the country to demonstrate this market-ready advanced technology. Produced and leased by Ford Motor Company , they consist of one 12- passenger bus and one nine-passenger bus. More information at: http://go.usa.gov/Tgr

  8. HYDROGEN ISOTOPE TARGETS

    DOEpatents

    Ashley, R.W.

    1958-08-12

    The design of targets for use in the investigation of nuclear reactions of hydrogen isotopes by bombardment with accelerated particles is described. The target con struction eomprises a backing disc of a metal selected from the group consisting of molybdenunn and tungsten, a eoating of condensed titaniunn on the dise, and a hydrogen isotope selected from the group consisting of deuterium and tritium absorbed in the coatiag. The proeess for preparing these hydrogen isotope targets is described.

  9. Hydrogen powered bus

    ScienceCinema

    None

    2016-07-12

    Take a ride on a new type of bus, fueled by hydrogen. These hydrogen taxis are part of a Department of Energy-funded deployment of hydrogen powered vehicles and fueling infrastructure at nine federal facilities across the country to demonstrate this market-ready advanced technology. Produced and leased by Ford Motor Company , they consist of one 12- passenger bus and one nine-passenger bus. More information at: http://go.usa.gov/Tgr

  10. New IR observations of Titan and potential of in-situ atmospheric analysis of the outer planets

    NASA Technical Reports Server (NTRS)

    Owen, T.

    1974-01-01

    Ground based telescopic observations of Titan and outer planet atmospheres are evaluated for their abundances and an effort is made to deduce the various hydrogen-to-carbon ratios. Jupiter and Saturn atmospheres seem to have roughly solar abundances as far as hydrogen and methane are concerned; for Uranus, Titan and Neptune these ratios are way down.

  11. On the Evolution of Hydrogen-Deficient White Dwarfs

    NASA Astrophysics Data System (ADS)

    Camisassa, M. E.; Althaus, L. G.; Rohrmann, R. D.; García–Berro, E.; Córsico, A. H.

    2017-03-01

    We present full evolutionary calculations for hydrogen-deficient white dwarfs. We take into account the evolutionary history of the progenitor stars, all relevant energy sources, element diffusion, and outer boundary conditions provided by new and detailed non-gray white dwarf model atmospheres for pure helium composition. Model atmospheres are based on the most up-to-date physical inputs. The calculations are extended down to an effective temperature of 2500 K. Our calculations provide a homogeneous set of evolutionary cooling tracks appropriate for mass and age determinations of old hydrogen-deficient white dwarfs.

  12. Diurnal variations of the Venusian hot hydrogen corona observed by SPICAV/VEX

    NASA Astrophysics Data System (ADS)

    Chaufray, J.; Bertaux, J.; Sulis, S.; Quemerais, E.; Leblanc, F.

    2013-12-01

    Atomic hydrogen in the upper atmosphere of Venus is produced by chemical reactions involving hydrogen bearing molecules such as H2O. Due to its low mass, atomic hydrogen can reach high altitudes and become the dominant species in the Venusian exosphere. In the Venusian upper atmosphere, ions - neutral interactions could produce the non-thermal hydrogen population that has been observed by numerous past missions and confirmed recently by Venus Express missions at dayside. Observations of the nightside Venusian hydrogen corona have been performed in October 2011 by SPICAV-UV on Venus Express. Both disk and limb have been observed. Disk observations can be reproduced by a unique thermal hydrogen population with a density larger than the dayside hydrogen density. Hot hydrogen is needed to reproduce the limb observations and the brightness ~three times larger than the brightness observed at dayside suggests that the hot hydrogen corona is strongly assymetric with a major source of hot hydrogen at nightside. In this presentation, we will present these new observations of the Venusian hydrogen corona at nightside and discuss the first estimates of the hydrogen density derived from comparison between observations and models.

  13. Conductive dense hydrogen.

    PubMed

    Eremets, M I; Troyan, I A

    2011-11-13

    Molecular hydrogen is expected to exhibit metallic properties under megabar pressures. This metal is predicted to be superconducting with a very high critical temperature, T(c), of 200-400 K, and it may acquire a new quantum state as a metallic superfluid and a superconducting superfluid. It may potentially be recovered metastably at ambient pressures. However, experiments carried out at low temperatures, T<100 K, showed that at record pressures of 300 GPa, hydrogen remains in the molecular insulating state. Here we report on the transformation of normal molecular hydrogen at room temperature (295 K) to a conductive and metallic state. At 200 GPa the Raman frequency of the molecular vibron strongly decreased and the spectral width increased, evidencing a strong interaction between molecules. Deuterium behaved similarly. Above 220 GPa, hydrogen became opaque and electrically conductive. At 260-270 GPa, hydrogen transformed into a metal as the conductance of hydrogen sharply increased and changed little on further pressurizing up to 300 GPa or cooling to at least 30 K; and the sample reflected light well. The metallic phase transformed back at 295 K into molecular hydrogen at 200 GPa. This significant hysteresis indicates that the transformation of molecular hydrogen into a metal is accompanied by a first-order structural transition presumably into a monatomic liquid state. Our findings open an avenue for detailed and comprehensive studies of metallic hydrogen.

  14. Thin film hydrogen sensor

    DOEpatents

    Lauf, Robert J.; Hoffheins, Barbara S.; Fleming, Pamela H.

    1994-01-01

    A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed.

  15. Hydrogen ion microlithography

    DOEpatents

    Tsuo, Y. Simon; Deb, Satyen K.

    1990-01-01

    Disclosed is a hydrogen ion microlithography process for use in microelectronic fabrication and semiconductor device processing. The process comprises the steps of providing a single layer of either an amorphous silicon or hydrogenated amorphous silicon material. A pattern is recorded in a selected layer of amorphous silicon or hydrogenated amorphous silicon materials by preferentially implanting hydrogen ions therein so as to permit the selected layer to serve as a mask-resist wafer suitable for subsequent development and device fabrication. The layer is developed to provide a surface pattern therein adaptable for subsequent use in microelectronic fabrication and semiconductor device processing.

  16. Hydrogen ion microlithography

    DOEpatents

    Tsuo, Y.S.; Deb, S.K.

    1990-10-02

    Disclosed is a hydrogen ion microlithography process for use in microelectronic fabrication and semiconductor device processing. The process comprises the steps of providing a single layer of either an amorphous silicon or hydrogenated amorphous silicon material. A pattern is recorded in a selected layer of amorphous silicon or hydrogenated amorphous silicon materials by preferentially implanting hydrogen ions therein so as to permit the selected layer to serve as a mask-resist wafer suitable for subsequent development and device fabrication. The layer is developed to provide a surface pattern therein adaptable for subsequent use in microelectronic fabrication and semiconductor device processing. 6 figs.

  17. Hydrogen energy creeps forward

    NASA Astrophysics Data System (ADS)

    Graff, G.

    1983-05-01

    There have been hopeful forecasts of a 21st centry 'hydrogen economy' in which cheap hydrogen fuel would finally end mankind's dependence on petroleum fuels. The present investigation is concerned with developments related to the possible realization of such forecasts. One vital factor involves the feasibility to provide hydrogen at competitive prices for use as a fuel. Industrial hydrogen is too expensive for applications involving a competition with currently used common fuels. A number of investigations are being conducted in the U.S. and in other countries with the aim to develop an economical process by which hydrogen can be obtained from water. There exist already a great number of feasible different approaches for obtaining hydrogen on the basis of the decomposition of the water molecule. However, problems still to be solved are related to the development of any of these approaches to the point of economic viability. Another crucial factor concerns the strorage of hydrogen. Automakers are testing hydrogen-powered cars in which hydrogen is stored in liquid form or with the aid of metal hydrides.

  18. Conductive dense hydrogen

    NASA Astrophysics Data System (ADS)

    Eremets, M. I.; Troyan, I. A.

    2011-12-01

    Molecular hydrogen is expected to exhibit metallic properties under megabar pressures. This metal is predicted to be superconducting with a very high critical temperature, Tc, of 200-400 K (ref. ), and it may acquire a new quantum state as a metallic superfluid and a superconducting superfluid. It may potentially be recovered metastably at ambient pressures. However, experiments carried out at low temperatures, T<100 K (refs , ), showed that at record pressures of 300 GPa, hydrogen remains in the molecular insulating state. Here we report on the transformation of normal molecular hydrogen at room temperature (295 K) to a conductive and metallic state. At 200 GPa the Raman frequency of the molecular vibron strongly decreased and the spectral width increased, evidencing a strong interaction between molecules. Deuterium behaved similarly. Above 220 GPa, hydrogen became opaque and electrically conductive. At 260-270 GPa, hydrogen transformed into a metal as the conductance of hydrogen sharply increased and changed little on further pressurizing up to 300 GPa or cooling to at least 30 K and the sample reflected light well. The metallic phase transformed back at 295 K into molecular hydrogen at 200 GPa. This significant hysteresis indicates that the transformation of molecular hydrogen into a metal is accompanied by a first-order structural transition presumably into a monatomic liquid state. Our findings open an avenue for detailed and comprehensive studies of metallic hydrogen.

  19. Sustainable hydrogen production

    SciTech Connect

    Block, D.L.; Linkous, C.; Muradov, N.

    1996-01-01

    This report describes the Sustainable Hydrogen Production research conducted at the Florida Solar Energy Center (FSEC) for the past year. The report presents the work done on the following four tasks: Task 1--production of hydrogen by photovoltaic-powered electrolysis; Task 2--solar photocatalytic hydrogen production from water using a dual-bed photosystem; Task 3--development of solid electrolytes for water electrolysis at intermediate temperatures; and Task 4--production of hydrogen by thermocatalytic cracking of natural gas. For each task, this report presents a summary, introduction/description of project, and results.

  20. Hydrogen diffusion fuel cell

    SciTech Connect

    Struthers, R.C.

    1987-08-04

    This patent describes a fuel cell comprising; an elongate case; a thin, flat separator part of non-porous, di-electric, hydrogen-permeable material between the ends of and extending transverse the case and defining anode and cathode chambers; a thin, flat anode part of non-porous, electric conductive, hydrogen-permeable metallic material in the anode chamber in flat contacting engagement with and co-extensive with the separator part; a flat, porous, catalytic cathode part in the cathode chamber in contacting engagement with the separator part; hydrogen supply means supplying hydrogen to the anode part within the anode chamber; oxidant gas supply means supplying oxidant gas to the cathode part within the cathode chamber; and, an external electric circuit connected with and between the anode and cathode parts. The anode part absorbs and is permeated by hydrogen supplied to it and diffuses the hydrogen to hydrogen ions and free electrons; the free electrons in the anode part are conducted from the anode part into the electric circuit to perform useful work. The hydrogen ions in the anode part move from the anode part through the separator part and into the cathode part. Free electrons are conducted by the electric circuit into the cathode part. The hydrogen ions, oxidant gas and free electrons in the cathode part react and generate waste, heat and water.

  1. Homeostatic tendencies of the earth's atmosphere

    NASA Technical Reports Server (NTRS)

    Lovelock, J. E.; Margulis, L.

    1974-01-01

    The concept is developed that the atmosphere of the earth flows in a closed system controlled by and for the biosphere. The environmental factors delimiting the biosphere are examined. It is found that neither oxygen nor pressure per se limit the distribution of life as a whole. Rather the major physical variables determining the distribution of organisms are solar radiation, temperature, water abundance, and the concentrations of hydrogen and other ions and elements. An attempt is made to model temperature and atmospheric composition of a lifeless earth.

  2. Innovative Balloon Buoyancy Techniques for Atmospheric Exploration

    NASA Technical Reports Server (NTRS)

    Jones, J.

    2000-01-01

    Until quite recently, the only practical means to control balloon buoyancy, and thus altitude, required consuming large amounts of fuel or the limited venting of helium balloons and/or dropping of ballast. With recent discoveries at JPL, novel long-life, balloon buoyancy techniques have been discovered that for the first time allow balloons to float in the primarily hydrogen atmospheres of Jupiter, Saturn, Uranus, and Neptune (using ambient fill-gas), and by using renewable energy sources, allow multiple controlled landings on Venus (using atmospheric temperature differences), Mars (solar heat), Titan (RTG heat), and Earth (planet radiant heat).

  3. Reduced hydrogen embrittlement susceptibility in platinum implanted high strength steel

    NASA Astrophysics Data System (ADS)

    Cowie, J. G.; Lowder, L. J.; Culbertson, R. J.; Kosik, W. E.; Brown, R.

    1991-07-01

    High strength steels suffer from a high susceptibility to hydrogen embrittlement in a corrosive atmosphere, a factor which limits their usefulness. A good catalyst, such as platinum, present on the surface of the steel may lead to a low value of hydrogen overvoltage, thereby reducing the accumulation and subsequent diffusion of atomic hydrogen into the metal. In the present study, platinum was implanted into high strength electroslag remelted (ESR) 4340 steel specimens to a dose of 10 16 atoms/cm 2. Both Pt-implanted and unimplanted specimens were rate charged with hydrogen. The relative concentration of diffusible hydrogen was determined using an electrochemical measurement device known as a Barnacle Electrode. The specimens implanted with platinum exhibited less diffusible hydrogen than the unimplanted steel. Slow strain rate notched-tensile tests, in an aqueous solution of 3.5 wt.% NaCI, were performed in order to evaluate the effect of hydrogen on strength and ductility. The Pt-implanted specimens were able to sustain significantly higher loads before fracture than their unimplanted counterparts. Scanning electron microscopy (SEM) verified the presence of brittle cracking typical of hydrogen embrittlement type failures. Degradation of mechanical properties due to hydrogen embrittlement was thus significantly reduced. This suggested that both the electrochemical and catalytic properties of the Pt-implanted surface were responsible for the improvement in properties.

  4. YMgGa as a hydrogen storage compound

    SciTech Connect

    Sahlberg, Martin; Zlotea, Claudia; Moretto, Pietro; Andersson, Yvonne

    2009-07-15

    The hydrogen absorption and desorption properties of the recently found ternary phase YMgGa have been studied. This compound absorbs 2.2 wt% hydrogen during the first cycle, but only 1.1 wt% can be stored reversibly for the following cycles under the applied pressure and temperature conditions. Hydrogen absorption and desorption properties were investigated by measuring the thermal desorption spectra and the pressure-composition isotherms while the crystal structure was determined using X-ray diffraction (XRD). The compound absorbs hydrogen at pressures above 0.2 MPa and 250 deg. C by decomposing into YH{sub 3} and MgGa. This reaction is reversed when heating the hydride in a He atmosphere; hydrogen is released and the YMgGa phase is partially recovered together with YGa{sub 2} and YH{sub 2}. The reformation of YMgGa occurs at temperatures below 450 deg. C on the expenses of hydrogen desorption from YH{sub 2}. This is not expected under these temperature conditions as YH{sub 2} normally does not desorb hydrogen below 800 deg. C. - Graphical abstract: Hydrogen absorption in YMgGa studied by in situ powder X-ray diffraction. The hydrogen absorption and desorption properties were investigated by thermal desorption spectra and pressure-composition isotherms.

  5. Hydrogen-Helium shock Radiation tests for Saturn Entry Probes

    NASA Technical Reports Server (NTRS)

    Cruden, Brett A.

    2016-01-01

    This paper describes the measurement of shock layer radiation in Hydrogen/Helium mixtures representative of that encountered by probes entering the Saturn atmosphere. Normal shock waves are measured in Hydrogen-Helium mixtures (89:11% by volume) at freestream pressures between 13-66 Pa (0.1-0.5 Torr) and velocities from 20-30 km/s. Radiance is quantified from the Vacuum Ultraviolet through Near Infrared. An induction time of several centimeters is observed where electron density and radiance remain well below equilibrium. Radiance is observed in front of the shock layer, the characteristics of which match the expected diffusion length of Hydrogen.

  6. A DONOR COMPLEX WITH TUNNELING HYDROGEN IN PURE GERMANIUM

    SciTech Connect

    Joos, B.; Haller, E.E.; Falicov, L.M.

    1980-02-01

    A shallow donor complex observed by several authors in ultrapure germanium grown in a hydrogen atmosphere is attributed to an oxygen-hydrogen system. Photoconductivity data under stress are presented. An abrupt transition in the spectra at a well-defined stress (2.1 x 10{sup 8} dyn cm{sup -2}) is found. It is explained by a theory which involves dynamic tunneling of the hydrogen in the vicinity of an oxygen center. The comparison with other complex donors and acceptors supports the model.

  7. Triple redundant hydrogen sensor with in situ calibration

    NASA Technical Reports Server (NTRS)

    Lantz, J. B.; Powell, J. D.; Schubert, F. H.; Koszenski, E. P.

    1980-01-01

    To meet sensing and calibration needs, an in situ calibration technique was developed. It is based on electrolytic generation of a hydrogen/air atmosphere within a hydrogen sensor. The hydrogen is generated from water vapor in the air, and being electrical in nature, the in situ calibration can be performed completely automatically in remote locations. Triply redundant sensor elements are integrated within a single, compact housing, and digital logic provides inter-sensor comparisons to warn of and identify malfunctioning sensor elements. An evaluation of this concept is presented.

  8. Hydrogen as an energy carrier

    SciTech Connect

    Winter, C.J.; Nitsch, J

    1988-01-01

    The book deals with the possibilities of an energetic utilization of hydrogen. This energy carrier can be produced from the unlimited energy sources solar energy, wind energy and hydropower, and from nuclear energy. It is also in a position to one day supplement or supersede the fossil energy carriers oil, coal and gas. Contents: Significance and Use of Hydrogen: Energy Supply Structures and the Importance of Gaseous Energy Carriers. Technologies for the Energetic Use of Hydrogen. Hydrogen as Raw Material. Safety Aspects of Hydrogen Energy. Production of Hydrogen from Nonfossil Primary Energy: Photovoltaic Electricity Generation. Thermo-mechanical Electricity Generation. Water Splitting Methods. Selected Hydrogen Production Systems. Storage, Transport and Distribution of Hydrogen. Design of a Future Hydrogen Energy Economy: Potential and Chances of Hydrogen. Hydrogen in a Future Energy Economy. Concepts for the Introduction of Nonfossil Hydrogen. Energy-economic Conditions and the Cooperation with Hydrogen Producing Countries. Index.

  9. Hydrogen from biomass: state of the art and research challenges

    SciTech Connect

    Milne, Thomas A; Elam, Carolyn C; Evans, Robert J

    2002-02-01

    The report was prepared for the International Energy Agency (IEA) Agreement on the Production and Utilization of Hydrogen, Task 16, Hydrogen from Carbon-Containing Materials. Hydrogen's share in the energy market is increasing with the implementation of fuel cell systems and the growing demand for zero-emission fuels. Hydrogen production will need to keep pace with this growing market. In the near term, increased production will likely be met by conventional technologies, such as natural gas reforming. In these processes, the carbon is converted to CO2 and released to the atmosphere. However, with the growing concern about global climate change, alternatives to the atmospheric release of CO2 are being investigated. Sequestration of the CO2 is an option that could provide a viable near-term solution. Reducing the demand on fossil resources remains a significant concern for many nations. Renewable-based processes like solar- or wind-driven electrolysis and photobiological water splitting hold great promise for clean hydrogen production; however, advances must still be made before these technologies can be economically competitive. For the near-and mid-term, generating hydrogen from biomass may be the more practical and viable, renewable and potentially carbon-neutral (or even carbon-negative in conjunction with sequestration) option. Recently, the IEA Hydrogen Agreement launched a new task to bring together international experts to investigate some of these near- and mid-term options for producing hydrogen with reduced environmental impacts. This review of the state of the art of hydrogen production from biomass was prepared to facilitate in the planning of work that should be done to achieve the goal of near-term hydrogen energy systems. The relevant technologies that convert biomass to hydrogen, with emphasis on thermochemical routes are described. In evaluating the viability of the conversion routes, each must be put in the context of the availability of

  10. Electrical conductivity of condensed molecular hydrogen in the giant planets

    NASA Technical Reports Server (NTRS)

    Smoluchowski, R.

    1972-01-01

    Theoretical interpretation of several phenomena concerning Jupiter and Saturn depends upon the electrical conductivity of molecular hydrogen which, according to present models, forms the outermost layer of both planets. The layer starts at the transition pressure between the metallic and the molecular form of hydrogen, that is around 1 Mbar, and extends to the outside limits of the atmosphere. Whether at the highest pressures (and temperatures) this layer is a solid or a dense fluid is not certain. In any case, the fluid is in supercritical condition so that there is only a gradual transition from dense liquid to a gaseous form. The two theories which require specific values of the conductivity of the condensed molecular hydrogen are those pertaining to the generation of a magnetic field in the liquid hydrogen rather than in the deep metallic interior (HIDE, 1967), and those concerned with the electromagnetic coupling and exchange of angular momentum between the liquid core and the solid molecular hydrogen mantle.

  11. Materials for the scavanging of hydrogen at high temperatures

    DOEpatents

    Shepodd, Timothy J.; Phillip, Bradley L.

    1997-01-01

    A hydrogen getter composition comprising a double or triple bonded hydrocarbon with a high melting point useful for removing hydrogen gas, to partial pressures below 0.01 torr, from enclosed spaces and particularly from vessels used for transporting or containing fluids at elevated temperatures. The hydrogen getter compositions disclosed herein and their reaction products will neither melt nor char at temperatures in excess of 100.degree. C. They possess significant advantages over conventional hydrogen getters, namely low risk of fire or explosion, no requirement for high temperature activation or operation, the ability to absorb hydrogen even in the presence of contaminants such as water, water vapor, common atmospheric gases and oil mists and are designed to be disposed within the confines of the apparatus. These getter materials can be mixed with binders, such as fluropolymers, which permit the getter material to be fabricated into useful shapes and/or impart desirable properties such as water repellency or impermeability to various gases.

  12. Materials for the scavanging of hydrogen at high temperatures

    DOEpatents

    Shepodd, Timothy J.; Phillip, Bradley L.

    1997-01-01

    A hydrogen getter composition comprising a double or triple bonded hydrocarbon with a high melting point useful for removing hydrogen gas, to partial pressures below 0.01 torr, from enclosed spaces and particularly from vessels used for transporting or containing fluids at elevated temperatures. The hydrogen getter compostions disclosed herein and their reaction products will neither melt nor char at temperatures in excess of 100C. They possess significant advantages over conventional hydrogen getters, namely low risk of fire or explosion, no requirement for high temperature activation or operation, the ability to absorb hydrogen even in the presence of contaminants such as water, water vapor, common atmospheric gases and oil mists and are designed to be disposed within the confines of the apparatus. These getter materials can be mixed with binders, such as fluropolymers, which permit the getter material to be fabricated into useful shapes and/or impart desirable properties such as water repellency or impermeability to various gases.

  13. Hydrogen Adsorption in Zeolite Studied with Sievert and Thermogravimetric Methods

    NASA Astrophysics Data System (ADS)

    Lesnicenoks, P.; Sivars, A.; Grinberga, L.; Kleperis, J.

    2012-08-01

    Natural clinoptilolite (mixture from clinoptilolite, quartz and muscovite) is activated with palladium and tested for hydrogen adsorption capability at temperatures RT - 200°C. Thermogravimetric and volumetric methods showed that zeolite activated with palladium (1.25%wt) shows markedly high hydrogen adsorption capacity - up to 3 wt%. Lower amount of adsorbed hydrogen (~1.5 wt%) was found for raw zeolite and activated with higher amount of palladium sample. Hypothesis is proposed that the heating of zeolite in argon atmosphere forms and activates the pore structure in zeolite material, where hydrogen encapsulation (trapping) is believed to occur when cooling down to room temperature. An effect of catalyst (Pd) on hydrogen sorption capability is explained by spillover phenomena were less-porous fractions of natural clinoptilolite sample (quartz and muscovite) are involved.

  14. The atomic hydrogen cloud in the saturnian system

    NASA Astrophysics Data System (ADS)

    Tseng, W.-L.; Johnson, R. E.; Ip, W.-H.

    2013-09-01

    The importance of Titan's H torus shaped by solar radiation pressure and of hydrogen atoms flowing out of Saturn's atmosphere in forming the broad hydrogen cloud in Saturn's magnetosphere is still debated. Since the Saturnian system also contains a water product torus which originates from the Enceladus plumes, the icy ring particles, and the inner icy satellites, as well as Titan's H2 torus, we have carried out a global investigation of the atomic hydrogen cloud taking into account all sources. We show that the velocity and angle distributions of the hot H ejected from Saturn's atmosphere following electron-impact dissociation of H2 are modified by collisions with the ambient atmospheric H2 and H. This in turn affects the morphology of the escaping hydrogen from Saturn, as does the morphology of the ionospheric electron distribution. Although an exact agreement with the Cassini observations is not obtained, our simulations show that H directly escaping from Titan is the dominant contributor in the outer magnetosphere. Of the total number of H observed by Cassini from 1 to 5RS, ∼5.7×1034, our simulations suggest ∼20% is from dissociation in the Enceladus torus, ∼5-10% is from dissociation of H2 in the atmosphere of the main rings, and ∼50% is from Titan's H torus, implying that ∼20% comes from Saturn atmosphere.

  15. HYDROGEN GREENHOUSE PLANETS BEYOND THE HABITABLE ZONE

    SciTech Connect

    Pierrehumbert, Raymond; Gaidos, Eric E-mail: gaidos@hawaii.edu

    2011-06-10

    We show that collision-induced absorption allows molecular hydrogen to act as an incondensible greenhouse gas and that bars or tens of bars of primordial H{sub 2}-He mixtures can maintain surface temperatures above the freezing point of water well beyond the 'classical' habitable zone defined for CO{sub 2} greenhouse atmospheres. Using a one-dimensional radiative-convective model, we find that 40 bars of pure H{sub 2} on a three Earth-mass planet can maintain a surface temperature of 280 K out to 1.5 AU from an early-type M dwarf star and 10 AU from a G-type star. Neglecting the effects of clouds and of gaseous absorbers besides H{sub 2}, the flux at the surface would be sufficient for photosynthesis by cyanobacteria (in the G star case) or anoxygenic phototrophs (in the M star case). We argue that primordial atmospheres of one to several hundred bars of H{sub 2}-He are possible and use a model of hydrogen escape to show that such atmospheres are likely to persist further than 1.5 AU from M stars, and 2 AU from G stars, assuming these planets have protecting magnetic fields. We predict that the microlensing planet OGLE-05-390Lb could have retained an H{sub 2}-He atmosphere and be habitable at {approx}2.6 AU from its host M star.

  16. Composition and physics of the lunar atmosphere.

    NASA Technical Reports Server (NTRS)

    Hoffman, J. H.; Hodges, R. R., Jr.; Johnson, F. S.; Evans , D. E.

    1973-01-01

    The existence in the lunar atmosphere of helium, neon, argon, and possibly molecular hydrogen has been confirmed by the Apollo 17 mass spectrometer. The observed helium concentrations and distribution agree closely with model predictions for a non-condensable gas based on a solar wind source, thermal escape and a Monte Carlo random walk calculated longitudinal distribution. Heavier gases are lost by photoionization and subsequent sweeping away by the solar wind electric field. The observed nighttime neon concentration of 80,000 molecules per cu cm is consistent with expected amounts. Argon, however, is adsorbed on the lunar surface late at night when the surface temperature is lowest. It shows the expected predawn enhancement exhibited by condensable gases released into the atmosphere at the sunrise terminator. Hydrogen appears to exist in the molecular rather than atomic state. Its observed concentration is less than a factor of 3 higher than that predicted by a model similar to that used for helium.

  17. Combination moisture and hydrogen getter

    DOEpatents

    Harrah, L.A.; Mead, K.E.; Smith, H.M.

    1983-09-20

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (1) a solid acetylenic compound and (2) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the resultant hydrogen.

  18. Combination moisture and hydrogen getter

    DOEpatents

    Harrah, Larry A.; Mead, Keith E.; Smith, Henry M.

    1983-01-01

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (i) a solid acetylenic compound and (ii) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the resultant hydrogen.

  19. Combination moisture and hydrogen getter

    DOEpatents

    Not Available

    1982-04-29

    A combination moisture and hydrogen getter comprises (a) a moisture getter comprising a readily oxidizable metal; and (b) a hydrogen getter comprising (i) a solid acetylenic compound and (ii) a hydrogenation catalyst. A method of scavenging moisture from a closed container uses the combination moisture and hydrogen getter to irreversibly chemically reduce the moisture and chemically bind the reusltant hydrogen.

  20. Enhancing hydrogen spillover and storage

    DOEpatents

    Yang, Ralph T.; Li, Yingwel; Lachawiec, Jr., Anthony J.

    2011-05-31

    Methods for enhancing hydrogen spillover and storage are disclosed. One embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the hydrogen receptor to ultrasonification as doping occurs. Another embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the doped hydrogen receptor to a plasma treatment.

  1. Enhancing hydrogen spillover and storage

    DOEpatents

    Yang, Ralph T; Li, Yingwei; Lachawiec, Jr., Anthony J

    2013-02-12

    Methods for enhancing hydrogen spillover and storage are disclosed. One embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the hydrogen receptor to ultrasonication as doping occurs. Another embodiment of the method includes doping a hydrogen receptor with metal particles, and exposing the doped hydrogen receptor to a plasma treatment.

  2. THE PRODUCTION OF HYDROGEN PEROXIDE BY HIGH OXYGEN PRESSURES

    PubMed Central

    Gilbert, Daniel L.; Gerschman, Rebeca; Ruhm, K. Barclay; Price, William E.

    1958-01-01

    Hydrogen peroxide is formed in solutions of glutathione exposed to oxygen. This hydrogen peroxide or its precursors will decrease the viscosity of polymers like desoxyribonucleic acid and sodium alginate. Further knowledge of the mechanism of these chemical effects of oxygen might further the understanding of the biological effects of oxygen. This study deals with the rate of solution of oxygen and with the decomposition of hydrogen peroxide in chemical systems exposed to high oxygen pressures. At 6 atmospheres, the absorption coefficient for oxygen into water was about 1 cm./hour and at 143 atmospheres, it was about 2 cm./hour; the difference probably being due to the modus operandi. The addition of cobalt (II), manganese (II), nickel (II), or zinc ions in glutathione (GSH) solutions exposed to high oxygen pressure decreased the net formation of hydrogen peroxide and also the reduced glutathione remaining in the solution. Studies on hydrogen peroxide decomposition indicated that these ions act probably by accelerating the hydrogen perioxide oxidation of glutathione. The chelating agent, ethylenediaminetetraacetic acid disodium salt, inhibited the oxidation of GSH exposed to high oxygen pressure for 14 hours. However, indication that oxidation still occurred, though at a much slower rate, was found in experiments lasting 10 weeks. Thiourea decomposed hydrogen peroxide very rapidly. When GSH solutions were exposed to high oxygen pressure, there was oxidation of the GSH, which became relatively smaller with increasing concentrations of GSH. PMID:13525677

  3. Acetylene fuel from atmospheric CO2 on Mars

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Linne, Diane L.

    1992-01-01

    The Mars mission scenario proposed by Baker and Zubrin (1990) intended for an unmanned preliminary mission is extended to maximize the total impulse of fuel produced with a minimum mass of hydrogen from Earth. The hydrogen along with atmospheric carbon dioxide is processed into methane and oxygen by the exothermic reaction in an atmospheric processing module. Use of simple chemical reactions to produce acetylene/oxygen rocket fuel on Mars from hydrogen makes it possible to produce an amount of fuel that is nearly 100 times the mass of hydrogen brought from earth. If such a process produces the return propellant for a manned Mars mission, the required mission mass in LEO is significantly reduced over a system using all earth-derived propellants.

  4. Greenhouse models of the atmosphere of Titan.

    NASA Technical Reports Server (NTRS)

    Pollack, J. B.

    1973-01-01

    The greenhouse effect is calculated for a series of Titanian atmosphere models with different proportions of methane, hydrogen, helium, and ammonia. A computer program is used in temperature-structure calculations based on radiative-convective thermal transfer considerations. A brightness temperature spectrum is derived for Titan and is compared with available observational data. It is concluded that the greenhouse effect on Titan is generated by pressure-induced transitions of methane and hydrogen. The helium-to-hydrogen ratio is found to have a maximum of about 1.5. The surface pressure is estimated to be at least 0.4 atm, with a daytime temperature of about 155 K at the surface. The presence of methane clouds in the upper troposphere is indicated. The clouds have a significant optical depth in the visible, but not in the thermal, infrared.

  5. Process for exchanging hydrogen isotopes between gaseous hydrogen and water

    SciTech Connect

    Hindin, Saul G.; Roberts, George W.

    1980-08-12

    A process for exchanging isotopes of hydrogen, particularly tritium, between gaseous hydrogen and water is provided whereby gaseous hydrogen depeleted in tritium and liquid or gaseous water containing tritium are reacted in the presence of a metallic catalyst.

  6. Resolution of Unresolved Safety Issue A-48, Hydrogen control measures and effects of hydrogen burns on safety equipment

    SciTech Connect

    Ferrell, C.M.; Soffer, L.

    1989-09-01

    Unresolved Safety Issue (USI) A-48 arose as a result of the large amount of hydrogen generated and burned within containment during the Three Mile Island accident. This issue covers hydrogen control measures for recoverable degraded-core accidents for all boiling-water reactors (BWRs) and those pressurized-water reactors (PWRs) with ice-condenser containments. The Commission and the nuclear industry have sponsored extensive research in this area, which has led to significant revision of the Commission's hydrogen control regulations, given in Title 10, Code of Federal Regulations, Part 50 (10 CFR 50), Section 50.44. BWRs having Mark I and II containments are presently required to operate with inerted containment atmospheres that effectively prevent hydrogen combustion. BWRs with Mark III containments and PWRs with ice-condenser containments are now required to be equipped with hydrogen control systems to protect containment integrity and safety systems inside containment. Industry has chosen to use hydrogen igniter systems to burn hydrogen produced in a controlled fashion to prevent damage. An independent review by a Committee of the National Research Council concluded that, for most accident scenarios, current regulatory requirements make it highly unlikely that hydrogen detonation would be the cause of containment failure. On the basis of the extensive research effort conducted and current regulatory requirements, including their implementation, the staff concludes that no new regulatory guidance on hydrogen control for recoverable degraded-core accidents for these types of plants is necessary and that USI A-48 is resolved.

  7. Membrane for hydrogen recovery from streams containing hydrogen sulfide

    SciTech Connect

    Agarwal, Pradeep K.

    2007-01-16

    A membrane for hydrogen recovery from streams containing hydrogen sulfide is provided. The membrane comprises a substrate, a hydrogen permeable first membrane layer deposited on the substrate, and a second membrane layer deposited on the first layer. The second layer contains sulfides of transition metals and positioned on the on a feed side of the hydrogen sulfide stream. The present invention also includes a method for the direct decomposition of hydrogen sulfide to hydrogen and sulfur.

  8. Hydrogen production by photoprocesses

    SciTech Connect

    Bull, S.R.

    1988-10-01

    The concept of producing hydrogen fuel from sunlight is inherently appealing and has captured the imagination of many scientists, innovators, and decision makers. In fact, there are numerous routes to produce hydrogen from solar energy through photoprocesses. Generally, they can be grouped into four processes: electric conversion, thermal conversion, indirect conversion, and direct photon conversion. 12 refs., 11 figs.

  9. Hydrogen from solar energy

    SciTech Connect

    Nix, R.G.

    1984-07-01

    This paper describes those portions of the Photo/Thermochemical Research Program that possibly apply to the production of hydrogen from sources such as water or hydrogen sulfide. That research centers around understanding high flux solids decomposition reactions and how to best exploit photoreactions so the energy contained in the entire solar spectrum is used. 2 references, 4 figures.

  10. Hydrogen Conference: Workshop Proceedings

    SciTech Connect

    1989-10-01

    Hydrogen is currently a major chemical/fuel with long-term energy system benefits that may impact the industry's physical and economic well-being. EPRI's recent hydrogen conference concluded that to be competitive, the production cost must take into account environmental and end-use efficiency benefits.

  11. Hydrogen evolution reaction catalyst

    DOEpatents

    Subbaraman, Ram; Stamenkovic, Vojislav; Markovic, Nenad; Tripkovic, Dusan

    2016-02-09

    Systems and methods for a hydrogen evolution reaction catalyst are provided. Electrode material includes a plurality of clusters. The electrode exhibits bifunctionality with respect to the hydrogen evolution reaction. The electrode with clusters exhibits improved performance with respect to the intrinsic material of the electrode absent the clusters.

  12. Thick film hydrogen sensor

    DOEpatents

    Hoffheins, Barbara S.; Lauf, Robert J.

    1995-01-01

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors.

  13. Thick film hydrogen sensor

    DOEpatents

    Hoffheins, B.S.; Lauf, R.J.

    1995-09-19

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors. 8 figs.

  14. Hydrogen in amorphous silicon

    SciTech Connect

    Peercy, P. S.

    1980-01-01

    The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH/sub 1/) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon.

  15. Travel with hydrogen

    NASA Astrophysics Data System (ADS)

    Hermans, L. J. F. Jo

    2017-03-01

    In the field of transportation, hydrogen does not have a particularly glorious history. Just think of the dozens of hydrogen airships destroyed by fire over the years, with the Hindenburg disaster in 1937 as the most famous example. Now H2 is trying a comeback on the road, often in combination with a fuel cell and an electric motor to power the car.

  16. Simultaneously photodeposited rhodium metal and oxide nanoparticles promoting photocatalytic hydrogen production.

    PubMed

    Shimura, Katsuya; Kawai, Hiromasa; Yoshida, Tomoko; Yoshida, Hisao

    2011-08-21

    Photodeposition of a Rh cocatalyst under atmospheric conditions could simultaneously provide both Rh metal and oxide nanoparticles on a K(2)Ti(6)O(13) photocatalyst, both of which cooperatively promoted the photocatalytic hydrogen production from water and methane.

  17. A HIGHLY EFFICIENT OXIDATION OF CYCLOHEXANE OVER VPO CATALYSTS USING HYDROGEN PEROXIDE

    EPA Science Inventory

    An unprecedented and highly efficient oxidation of cyclohexane to cyclohexanol and cyclohexanone is accomplished over calcined vanadium phosphorus oxide (VPO) catalysts in a relatively mild condition using hydrogen peroxide under a nitrogen atmosphere.

  18. Refractory coating protects intricate graphite elements from high-temperature hydrogen

    NASA Technical Reports Server (NTRS)

    Ferris, J. R.; Patterson, R. L.; Steffen, R. J.; Vogel, C. E.

    1966-01-01

    Refractory coating protects graphite heater elements operating at high temperature in a hydrogen atmosphere. The coating is formed by painting the graphite elements with a composition containing powdered tungsten, and heat-treating it.

  19. Hydrogen utilization and alternatives

    NASA Technical Reports Server (NTRS)

    Manvi, R.; Caputo, R.; Fujita, T.

    1975-01-01

    The historical uses of hydrogen are described along with potential new uses which could develop as a result of the diminishing supply of conventional fossil fuels such as natural gas. A perspective view of hydrogen, both as a chemical feedstock and as a fuel, is necessary to understand its relationship to the overall national energy projections. These projections, which show energy usage in terms of use sectors, forms of energy, and sources of energy, do not specifically identify hydrogen as a component of the energy system. By superimposing the traditional roles upon the new opportunities for hydrogen on the energy projections, the role of hydrogen and future projections is developed within the context of the national energy projections. Use, supply, and other factors affecting application are interrelated and are discussed.

  20. Atomic hydrogen rocket engine

    NASA Technical Reports Server (NTRS)

    Etters, R. D.; Flurchick, K.

    1981-01-01

    A rocket using atomic hydrogen propellant is discussed. An essential feature of the proposed engine is that the atomic hydrogen fuel is used as it is produced, thus eliminating the necessity of storage. The atomic hydrogen flows into a combustion chamber and recombines, producing high velocity molecular hydrogen which flows out an exhaust port. Standard thermodynamics, kinetic theory and wall recombination cross-sections are used to predict a thrust of approximately 1.4 N for a RF hydrogen flow rate of 4 x 10 to the 22nd/sec. Specific impulses are nominally from 1000 to 2000 sec. It is predicted that thrusts on the order of one Newton and specific impulses of up to 2200 sec are attainable with nominal RF discharge fluxes on the order of 10 to the 22nd atoms/sec; further refinements will probably not alter these predictions by more than a factor of two.

  1. Hydrogen Fuel Quality

    SciTech Connect

    Rockward, Tommy

    2012-07-16

    For the past 6 years, open discussions and/or meetings have been held and are still on-going with OEM, Hydrogen Suppliers, other test facilities from the North America Team and International collaborators regarding experimental results, fuel clean-up cost, modeling, and analytical techniques to help determine levels of constituents for the development of an international standard for hydrogen fuel quality (ISO TC197 WG-12). Significant progress has been made. The process for the fuel standard is entering final stages as a result of the technical accomplishments. The objectives are to: (1) Determine the allowable levels of hydrogen fuel contaminants in support of the development of science-based international standards for hydrogen fuel quality (ISO TC197 WG-12); and (2) Validate the ASTM test method for determining low levels of non-hydrogen constituents.

  2. Challenges in hydrogen storage

    NASA Astrophysics Data System (ADS)

    Schüth, F.

    2009-09-01

    Hydrogen is one possible medium for energy storage and transportation in an era beyond oil. Hydrogen appears to be especially promising in connection with electricity generation in polymer electrolyte membrane (PEM) fuel cells in cars. However, before such technologies can be implemented on a larger scale, satisfactory solutions for on-board storage of hydrogen are required. This is a difficult task due to the low volumetric and gravimetric storage density on a systems level which can be achieved so far. Possibilities include cryogenic storage as liquid hydrogen, high pressure storage at 70 MPa, (cryo)adsorptive storage, or various chemical methods of binding and releasing hydrogen. This survey discusses the different options and the associated advantages and disadvantages.

  3. Hydrogen Peroxide Concentrator

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F.

    2007-01-01

    A relatively simple and economical process and apparatus for concentrating hydrogen peroxide from aqueous solution at the point of use have been invented. The heart of the apparatus is a vessel comprising an outer shell containing tubular membranes made of a polymer that is significantly more permeable by water than by hydrogen peroxide. The aqueous solution of hydrogen peroxide to be concentrated is fed through the interstitial spaces between the tubular membranes. An initially dry sweep gas is pumped through the interiors of the tubular membranes. Water diffuses through the membranes and is carried away as water vapor mixed into the sweep gas. Because of the removal of water, the hydrogen peroxide solution flowing from the vessel at the outlet end is more concentrated than that fed into the vessel at the inlet end. The sweep gas can be air, nitrogen, or any other gas that can be conveniently supplied in dry form and does not react chemically with hydrogen peroxide.

  4. Tandem hydroformylation/hydrogenation of alkenes to normal alcohols using Rh/Ru dual catalyst or Ru single component catalyst.

    PubMed

    Takahashi, Kohei; Yamashita, Makoto; Nozaki, Kyoko

    2012-11-14

    The catalyst system for tandem hydroformylation/hydrogenation of terminal alkenes to the corresponding homologated normal alcohol was developed. The reaction mechanism for the Rh/Ru dual catalyst was investigated by real-time IR monitoring experiments and (31)P NMR spectroscopy, which proved the mutual orthogonality of Rh-catalyzed hydroformylation and Ru-catalyzed hydrogenation. Detailed investigation about Ru-catalyzed hydrogenation of undecanal under H(2)/CO pressure clarified different kinetics from the hydrogenation under H(2) and gave a clue to design more active hydrogenation catalysts under H(2)/CO atmosphere. The solely Ru-catalyzed normal selective hydroformylation/hydrogenation is also reported.

  5. An introduction to hydrogen energy

    NASA Astrophysics Data System (ADS)

    Shpilrain, E. E.; Malyshenko, S. P.; Kuleshov, G. G.

    Problems related to the use of hydrogen as a source of energy are reviewed. In particular, attention is given to the physicochemical properties of hydrogen; methods of hydrogen production, including traditional and newly developed processes; and storage, transportation and distribution of hydrogen gas. Results of technical and cost-effectiveness analyses are presented for various hydrogen power systems; the principal applications of hydrogen power are discussed.

  6. Atmospheric and Space Sciences: Neutral Atmospheres

    NASA Astrophysics Data System (ADS)

    Yiǧit, Erdal

    2015-09-01

    The SpringerBriefs on Atmospheric and Space Sciences in two volumes presents a concise and interdisciplinary introduction to the basic theory, observation & modeling of atmospheric and ionospheric coupling processes on Earth. The goal is to contribute toward bridging the gap between meteorology, aeronomy, and planetary science. In addition recent progress in several related research topics, such atmospheric wave coupling and variability, is discussed. Volume 1 will focus on the atmosphere, while Volume 2 will present the ionosphere— the plasma environment. Volume 1 is aimed primarily at (research) students and researchers that would like to gain quick insight in atmospheric sciences and current research. It also is a useful tool for professors who would like to develop a course in atmospheric physics.

  7. Lichnost' i ee formirovanie v detskom vozraste: psihologiceskoe issledovanie (Personality and Its Development in Childhood: A Psychological Investigation).

    ERIC Educational Resources Information Center

    Bozovic, L. I.

    This document is an English-language abstract (approximately 1,500 words) of a three-part volume on the psychology of child personality development. In part one, the author shows that psychology is one of the most important scientific disciplines on which education is based, particularly because of its contribution to the scientific planning of…

  8. Hydrogen embrittlement property of a 1700-MPa-class ultrahigh-strength tempered martensitic steel

    PubMed Central

    Li, Songjie; Akiyama, Eiji; Yuuji, Kimura; Tsuzaki, Kaneaki; Uno, Nobuyoshi; Zhang, Boping

    2010-01-01

    The hydrogen embrittlement property of a prototype 1700-MPa-class ultrahigh-strength steel (NIMS17) containing hydrogen traps was evaluated using a slow strain rate test (SSRT) after cathodic hydrogen precharging, cyclic corrosion test (CCT) and atmospheric exposure. The hydrogen content in a fractured specimen was measured after SSRT by thermal desorption spectroscopy (TDS). The relationship between fracture stress and hydrogen content for the hydrogen-precharged specimens showed that the fracture stress of NIMS17 steel was higher, at a given hydrogen content, than that of conventional AISI 4135 steels with tensile strengths of 1300 and 1500 MPa. This suggests better resistance of NIMS17 steel to hydrogen embrittlement. However, hydrogen uptake to NIMS17 steel under CCT and atmospheric exposure decreased the fracture stress. This is because of the stronger hydrogen uptake to the steel containing hydrogen traps than to the AISI 4135 steels. Although NIMS17 steel has a higher strength level than AISI 4135 steel with a tensile strength of 1500 MPa, the decrease in fracture stress is similar between these steels. PMID:27877333

  9. Hydrogen embrittlement property of a 1700-MPa-class ultrahigh-strength tempered martensitic steel.

    PubMed

    Li, Songjie; Akiyama, Eiji; Yuuji, Kimura; Tsuzaki, Kaneaki; Uno, Nobuyoshi; Zhang, Boping

    2010-04-01

    The hydrogen embrittlement property of a prototype 1700-MPa-class ultrahigh-strength steel (NIMS17) containing hydrogen traps was evaluated using a slow strain rate test (SSRT) after cathodic hydrogen precharging, cyclic corrosion test (CCT) and atmospheric exposure. The hydrogen content in a fractured specimen was measured after SSRT by thermal desorption spectroscopy (TDS). The relationship between fracture stress and hydrogen content for the hydrogen-precharged specimens showed that the fracture stress of NIMS17 steel was higher, at a given hydrogen content, than that of conventional AISI 4135 steels with tensile strengths of 1300 and 1500 MPa. This suggests better resistance of NIMS17 steel to hydrogen embrittlement. However, hydrogen uptake to NIMS17 steel under CCT and atmospheric exposure decreased the fracture stress. This is because of the stronger hydrogen uptake to the steel containing hydrogen traps than to the AISI 4135 steels. Although NIMS17 steel has a higher strength level than AISI 4135 steel with a tensile strength of 1500 MPa, the decrease in fracture stress is similar between these steels.

  10. Hydrogen embrittlement property of a 1700-MPa-class ultrahigh-strength tempered martensitic steel

    NASA Astrophysics Data System (ADS)

    Li, Songjie; Akiyama, Eiji; Yuuji, Kimura; Tsuzaki, Kaneaki; Uno, Nobuyoshi; Zhang, Boping

    2010-04-01

    The hydrogen embrittlement property of a prototype 1700-MPa-class ultrahigh-strength steel (NIMS17) containing hydrogen traps was evaluated using a slow strain rate test (SSRT) after cathodic hydrogen precharging, cyclic corrosion test (CCT) and atmospheric exposure. The hydrogen content in a fractured specimen was measured after SSRT by thermal desorption spectroscopy (TDS). The relationship between fracture stress and hydrogen content for the hydrogen-precharged specimens showed that the fracture stress of NIMS17 steel was higher, at a given hydrogen content, than that of conventional AISI 4135 steels with tensile strengths of 1300 and 1500 MPa. This suggests better resistance of NIMS17 steel to hydrogen embrittlement. However, hydrogen uptake to NIMS17 steel under CCT and atmospheric exposure decreased the fracture stress. This is because of the stronger hydrogen uptake to the steel containing hydrogen traps than to the AISI 4135 steels. Although NIMS17 steel has a higher strength level than AISI 4135 steel with a tensile strength of 1500 MPa, the decrease in fracture stress is similar between these steels.

  11. Hydrogen Data Book from the Hydrogen Analysis Resource Center

    DOE Data Explorer

    The Hydrogen Data Book contains a wide range of factual information on hydrogen and fuel cells (e.g., hydrogen properties, hydrogen production and delivery data, and information on fuel cells and fuel cell vehicles), and it also provides other data that might be useful in analyses of hydrogen infrastructure in the United States (e.g., demographic data and data on energy supply and/or infrastructure). ItÆs made available from the Hydrogen Analysis Resource Center along with a wealth of related information. The related information includes guidelines for DOE Hydrogen Program Analysis, various calculator tools, a hydrogen glossary, related websites, and analysis tools relevant to hydrogen and fuel cells. [From http://hydrogen.pnl.gov/cocoon/morf/hydrogen

  12. Measuring Hydrogen Concentrations in Metals

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1985-01-01

    Commercial corrosion-measurement system adapted to electrochemical determination of hydrogen concentrations in metals. New technique based on diffusion of hydrogen through foil specimen of metal. In sample holder, hydrogen produced on one side of foil, either by corrosion reaction or by cathodic current. Hydrogen diffused through foil removed on other side by constant anode potential, which leads to oxidation of hydrogen to water. Anode current is measure of concentration of hydrogen diffusing through foil. System used to study hydrogen uptake, hydrogen elimination by baking, effect of heat treatment, and effect of electroplating on high-strength steels.

  13. Mass fractionation of noble gases in diffusion-limited hydrodynamic hydrogen escape.

    PubMed

    Zahnle, K; Kasting, J F; Pollack, J B

    1990-01-01

    Mass fractionation by hydrodynamic hydrogen escape is a promising mechanism for explaining the observed elemental and isotopic abundance patterns in terrestrial planet atmospheres. Previous work has considered only pure hydrogen winds. Here, the theory of mass fractionation by hydrogen escape is extended to atmospheres in which hydrogen is not the only major constituent. Analytical solutions are derived for cases in which all relevant atmospheric constituents escape; both analytical and numerical solutions are obtained for cases in which important heavy constituents are retained. In either case the fractionation patterns that result can differ significantly from those produced by pure hydrogen winds. Three applications of the theory are discussed: (1) The observed fractionation of terrestrial atmospheric neon with respect to mantle neon can be explained as a by-product of diffusion-limited hydrogen escape from a steam atmosphere toward the end of accretion. (2) The anomalously high Martian (SNC) 38Ar/36Ar ratio is attributed to hydrodynamic fractionation by a vigorously escaping, nearly pure hydrogen wind. (3) It is possible that the present high Martian D/H ratio was established during the same hydrodynamic escape phase that fractionated argon, but the predicted degree of D/H enrichment is sensitive to other, less well constrained parameters.

  14. Adsorption of hydrogen chloride on microcrystalline silica. [solid rocket propellant exhaust

    NASA Technical Reports Server (NTRS)

    Kang, Y.; Wightman, J. P.

    1979-01-01

    The interaction of hydrogen chloride with quartz was studied to determine the extent to which silica can irreversibly remove hydrogen chloride from the atmosphere. Adsorption isotherms were measured at 30 C for hydrogen chloride on silica outgassed between 100 C and 400 C. Readsorption isotherms were also measured. The silica surface was characterized further by infrared spectroscopy, electron spectroscopy for chemical analysis, scanning electron microscopy, and immersional calorimetry. Ground debris samples obtained from the Kennedy Space Center, were likewise examined.

  15. Hydrogen halide cleaning of powder metallurgy nickel-20 chromium-3 thoria.

    NASA Technical Reports Server (NTRS)

    Herbell, T. P.

    1972-01-01

    The Cr2O3 content of powder metallurgy nickel-20 chromium-3 thoria was reduced with atmospheres consisting of hydrogen plus hydrogen chloride (HCl) or hydrogen bromide (HBr). The nonthoria oxygen content or 'oxygen excess' was reduced from an initial amount of greater than 50,000 ppm to less than 100 ppm. Low temperatures were effective, but lowest oxygen levels were achieved with the highest cleaning temperature of 1200 C.

  16. Products of binary complex compounds thermolysis: Catalysts for hydrogen peroxide decomposition

    NASA Astrophysics Data System (ADS)

    Domonov, D. P.; Pechenyuk, S. I.; Gosteva, A. N.

    2014-06-01

    Samples are obtained via the thermolysis of binary complex compounds in a hydrogen atmosphere. Their catalytic activity in hydrogen peroxide decomposition is studied. The values of the rate constants and activation energies for the catalytic reaction are estimated. The correlation between catalytic activity, composition, specific surface area ( S sp), and particle size of the samples is analyzed.

  17. Photoelectrochemical hydrogen production

    SciTech Connect

    Rocheleau, R.; Misra, A.; Miller, E.

    1998-08-01

    A significant component of the US DOE Hydrogen Program is the development of a practical technology for the direct production of hydrogen using a renewable source of energy. High efficiency photoelectrochemical systems to produce hydrogen directly from water using sunlight as the energy source represent one of the technologies identified by DOE to meet this mission. Reactor modeling and experiments conducted at UH provide strong evidence that direct solar-to-hydrogen conversion efficiency greater than 10% can be expected using photoelectrodes fabricated from low-cost, multijunction (MJ) amorphous silicon solar cells. Solar-to-hydrogen conversion efficiencies as high as 7.8% have been achieved using a 10.3% efficient MJ amorphous silicon solar cell. Higher efficiency can be expected with the use of higher efficiency solar cells, further improvement of the thin film oxidation and reduction catalysts, and optimization of the solar cell for hydrogen production rather than electricity production. Hydrogen and oxygen catalysts developed under this project are very stable, exhibiting no measurable degradation in KOH after over 13,000 hours of operation. Additional research is needed to fully optimize the transparent, conducting coatings which will be needed for large area integrated arrays. To date, the best protection has been afforded by wide bandgap amorphous silicon carbide films.

  18. Hydrogen uptake in single-walled carbon nanotubes synthesized by the hydrogen arc plasma jet method.

    NASA Astrophysics Data System (ADS)

    Moreno-Ruiz, L. A.; Ortiz-Lopez, J.; de Ita de La Torre, A.; Arellano-Peraza, J. S.; Flores-Díaz, G.

    2006-03-01

    Carbon nanotubes were synthesized by a modified electric arc discharge method under hydrogen atmosphere using a catalytic mixture of powders with composition C/Ni/Co/Fe/FeS. The samples were characterized with transmission and scanning electron microscopy, Raman spectroscopy and thermo-gravimetric analysis. Unpurified samples contain 20 wt% of carbon nanotubes, 2 wt% of other forms of carbon and 78 wt% of catalytic metals. Adsorption/desorption of hydrogen in unpurified samples at atmospheric pressure measured with gravimetric methods was of the order of 2 wt%. Samples for these measurements were prepared with a three-step treatment: (i) oxidation in air for 30 min at 500 ^oC, (ii) ball- milling for 1 hr, and (iii) second oxidation in air for 30 min at 500 ^oC. This treatment was applied to eliminate other forms of carbon as well as to shorten the tubes and open their caps. Hydrogen desorption was also measured in degassed samples (400 ^oC for 20 min in vacuum) which adsorbed H2 while cooling to room temperature. Desorption in degassed/hydrogenated samples is a two-step process which we attribute to distinct desorption characteristics of nanotubes and of residual oxidized metal catalysts.

  19. Ductility Loss in Ductile Cast Iron with Internal Hydrogen

    NASA Astrophysics Data System (ADS)

    Matsunaga, Hisao; Usuda, Teruki; Yanase, Keiji; Endo, Masahiro

    2013-11-01

    Hydrogen-induced ductility loss in ductile cast iron (DCI) was studied by conducting a series of tensile tests with three different crosshead speeds. By utilizing the thermal desorption spectroscopy and the hydrogen microprint technique, it was found that most of the solute hydrogen was diffusive and mainly segregated at the graphite, graphite/matrix interface zone, and the cementite of pearlite in the matrix. The fracture process of the non-charged specimen was dominated by the ductile dimple fracture, whereas that of the hydrogen-charged specimen became less ductile because of the accompanying interconnecting cracks between the adjacent graphite nodules. Inside the hydrogen-charged specimen, the interspaces generated by the interfacial debonding between graphite and matrix are filled with hydrogen gas in the early stage of the fracture process. In the subsequent fracture process, such a local hydrogen gas atmosphere coupled with a stress-induced diffusion attracts hydrogen to the crack tip, which results in a time-dependent ductility loss.

  20. Hydrogen storage and generation using light metal hydrides

    SciTech Connect

    Lynch, F.; Mork, B.J.; Wilkes, J.S.

    1998-07-01

    The storage of hydrogen for use in fuel cells employed as portable electric power sources is important. For many applications pressurized gas or cryogenic liquid storage is not acceptable from weight or safety standpoints. This is particularly true for moderate power systems in the 50--200 watt range. A potentially attractive technology for providing hydrogen for moderately sized fuel cell-based electric power supplies is chemical hydrides. In general, chemical hydrides are materials that store hydrogen that may be released by chemical reactions. The authors report here the use of light metal hydrides, such as lithium aluminum tetrahydride and trilithium aluminum hexahydride to store hydrogen in a very dense form; about four times the density of liquid hydrogen. The hydrogen can be released by reaction with simple chemical reagents, such as water or ammonia, at approximately atmospheric pressure and at modest temperatures. The reaction rate may be controlled to provide hydrogen at a rate appropriate to that needed by a fuel cell operating at the power levels mentioned above. Usually hydrogen is the sole gaseous product, along with several solid products.

  1. Earth’s Earliest Atmospheres

    PubMed Central

    Zahnle, Kevin; Schaefer, Laura; Fegley, Bruce

    2010-01-01

    Earth is the one known example of an inhabited planet and to current knowledge the likeliest site of the one known origin of life. Here we discuss the origin of Earth’s atmosphere and ocean and some of the environmental conditions of the early Earth as they may relate to the origin of life. A key punctuating event in the narrative is the Moon-forming impact, partly because it made Earth for a short time absolutely uninhabitable, and partly because it sets the boundary conditions for Earth’s subsequent evolution. If life began on Earth, as opposed to having migrated here, it would have done so after the Moon-forming impact. What took place before the Moon formed determined the bulk properties of the Earth and probably determined the overall compositions and sizes of its atmospheres and oceans. What took place afterward animated these materials. One interesting consequence of the Moon-forming impact is that the mantle is devolatized, so that the volatiles subsequently fell out in a kind of condensation sequence. This ensures that the volatiles were concentrated toward the surface so that, for example, the oceans were likely salty from the start. We also point out that an atmosphere generated by impact degassing would tend to have a composition reflective of the impacting bodies (rather than the mantle), and these are almost without exception strongly reducing and volatile-rich. A consequence is that, although CO- or methane-rich atmospheres are not necessarily stable as steady states, they are quite likely to have existed as long-lived transients, many times. With CO comes abundant chemical energy in a metastable package, and with methane comes hydrogen cyanide and ammonia as important albeit less abundant gases. PMID:20573713

  2. Chemochromic Hydrogen Leak Detectors

    NASA Technical Reports Server (NTRS)

    Roberson, Luke; Captain, Janine; Williams, Martha; Smith, Trent; Tate, LaNetra; Raissi, Ali; Mohajeri, Nahid; Muradov, Nazim; Bokerman, Gary

    2009-01-01

    At NASA, hydrogen safety is a key concern for space shuttle processing. Leaks of any level must be quickly recognized and addressed due to hydrogen s lower explosion limit. Chemo - chromic devices have been developed to detect hydrogen gas in several embodiments. Because hydrogen is odorless and colorless and poses an explosion hazard, there is an emerging need for sensors to quickly and accurately detect low levels of leaking hydrogen in fuel cells and other advanced energy- generating systems in which hydrogen is used as fuel. The device incorporates a chemo - chromic pigment into a base polymer. The article can reversibly or irreversibly change color upon exposure to hydrogen. The irreversible pigment changes color from a light beige to a dark gray. The sensitivity of the pigment can be tailored to its application by altering its exposure to gas through the incorporation of one or more additives or polymer matrix. Furthermore, through the incorporation of insulating additives, the chemochromic sensor can operate at cryogenic temperatures as low as 78 K. A chemochromic detector of this type can be manufactured into any feasible polymer part including injection molded plastic parts, fiber-spun textiles, or extruded tapes. The detectors are simple, inexpensive, portable, and do not require an external power source. The chemochromic detectors were installed and removed easily at the KSC launch pad without need for special expertise. These detectors may require an external monitor such as the human eye, camera, or electronic detector; however, they could be left in place, unmonitored, and examined later for color change to determine whether there had been exposure to hydrogen. In one type of envisioned application, chemochromic detectors would be fabricated as outer layers (e.g., casings or coatings) on high-pressure hydrogen storage tanks and other components of hydrogen-handling systems to provide visible indications of hydrogen leaks caused by fatigue failures or

  3. A Hydrogen Utopia?

    SciTech Connect

    Cherry, Robert Stephen; Reynolds, Bruce Allen

    2004-01-01

    The use of hydrogen as a fuel for transportation and stationary applications is receiving much favorable attention as a technical and policy issue. However, the widespread introduction of this technology is likely also to have negative consequences that are not being actively discussed in broad public forums. Such possibilities include, among others, delayed development of other energy alternatives, hazards of catalyst or hydride metals, disruptive employment shifts, land usage conflicts, and increased vehicle usage. Even though hydrogen is likely to be beneficial in its overall societal and environmental effects, hydrogen technology advocates must understand the range of problematic issues and prepare to address them.

  4. Biological hydrogen production

    SciTech Connect

    Benemann, J.R.

    1995-11-01

    Biological hydrogen production can be accomplished by either thermochemical (gasification) conversion of woody biomass and agricultural residues or by microbiological processes that yield hydrogen gas from organic wastes or water. Biomass gasification is a well established technology; however, the synthesis gas produced, a mixture of CO and H{sub 2}, requires a shift reaction to convert the CO to H{sub 2}. Microbiological processes can carry out this reaction more efficiently than conventional catalysts, and may be more appropriate for the relatively small-scale of biomass gasification processes. Development of a microbial shift reaction may be a near-term practical application of microbial hydrogen production.

  5. Chromatographic hydrogen isotope separation

    DOEpatents

    Aldridge, Frederick T.

    1981-01-01

    Intermetallic compounds with the CaCu.sub.5 type of crystal structure, particularly LaNiCo.sub.4 and CaNi.sub.5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation colum. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale mutli-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  6. Chromatographic hydrogen isotope separation

    DOEpatents

    Aldridge, F.T.

    Intermetallic compounds with the CaCu/sub 5/ type of crystal structure, particularly LaNiCo/sub 4/ and CaNi/sub 5/, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation column. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale multi-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen cn produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  7. SEARCHING FOR HYDROGEN IN TYPE Ib SUPERNOVAE

    SciTech Connect

    James, Spencer; Baron, E.

    2010-08-01

    We present synthetic spectral fits of the typical Type Ib SN 1999dn and the hydrogen-rich Ib SN 2000H using the generalized non-local thermodynamic equilibrium stellar atmospheres code PHOENIX. We fit model spectra to five epochs of SN 1999dn ranging from 10 days pre-maximum light to 17 days post-maximum light and to the two earliest epochs of SN 2000H available, maximum light and six days post-maximum. Our goal is to investigate the possibility of hydrogen in Type Ib supernovae (SNe Ib), specifically a feature around 6200 A which has previously been attributed to high-velocity H{alpha}. In earlier work on SN 1999dn we found the most plausible alternative to H{alpha} to be a blend of Si II and Fe II lines which can be adjusted to fit by increasing the metallicity. Our models are simple; they assume a power-law density profile with radius, homologous expansion, and solar compositions. The helium core is produced by 'burning' 4H{yields}He in order to conserve the nucleon number. For models with hydrogen the outer skin of the model consists of a shell of solar composition. The hydrogen mass of the standard solar composition shell is M{sub H} {approx}< 10{sup -3} M{sub sun} in SN 1999dn and M{sub H} {approx}< 0.2 M{sub sun} for SN 2000H. Our models fit the observed spectra reasonably well, successfully reproducing most features including the characteristic He I absorptions. The hydrogen feature in SN 1999dn is clear, but much more pronounced in SN 2000H. We discuss a possible evolutionary scenario that accounts for the dichotomy in the hydrogen shell mass between these two SNe.

  8. Atmospheric Mining in the Outer Solar System:. [Aerial Vehicle Reconnaissance and Exploration Options

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan A.

    2014-01-01

    Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and hydrogen can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and hydrogen (deuterium, etc.) were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of atmospheric mining in the outer solar system. This included the gas capturing rate, storage options, and different methods of direct use of the captured gases. Additional supporting analyses were conducted to illuminate vehicle sizing and orbital transportation issues. While capturing 3He, large amounts of hydrogen and 4He are produced. With these two additional gases, the potential for fueling small and large fleets of additional exploration and exploitation vehicles exists. Additional aerospacecraft or other aerial vehicles (UAVs, balloons, rockets, etc.) could fly through the outer planet atmospheres, for global weather observations, localized storm or other disturbance investigations, wind speed measurements, polar observations, etc. Deep-diving aircraft (built with the strength to withstand many atmospheres of pressure) powered by the excess hydrogen or helium 4 may be designed to probe the higher density regions of the gas giants. Outer planet atmospheric properties, atmospheric storm data, and mission planning for future outer planet UAVs are presented.

  9. Atmospheric Mining in the Outer Solar System: Resource Capturing, Storage, and Utilization

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2012-01-01

    Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and hydrogen can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and hydrogen (deuterium, etc.) were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of atmospheric mining in the outer solar system. This included the gas capturing rate for hydrogen helium 4 and helium 3, storage options, and different methods of direct use of the captured gases. Additional supporting analyses were conducted to illuminate vehicle sizing and orbital transportation issues.

  10. Atmospheric Mining in the Outer Solar System: Resource Capturing, Storage, and Utilization

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    2014-01-01

    Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as helium 3 and hydrogen can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and hydrogen (deuterium, etc.) were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of atmospheric mining in the outer solar system. This included the gas capturing rate for hydrogen helium 4 and helium 3, storage options, and different methods of direct use of the captured gases. Additional supporting analyses were conducted to illuminate vehicle sizing and orbital transportation issues.

  11. Pulse beam heating of the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Karlicky, Marian

    1990-12-01

    A response of the solar atmosphere to pulse beam heating is computed using a one-dimensional hybrid code. While the hydrodynamic part of this program is used to compute the atmospheric response, the pulse beam decelerated by electron-electron and electron-neutral hydrogen interactions in the dense layers of the solar atmosphere is represented by particles. In this new description of an electron beam, the finite transit time of accelerated electrons in the flare loops is taken into account and the hard X-ray radiation is computed directly. Four different pulse beams are considered and their effects are compared. Moreover, the return current losses of the pulse beam are discussed.

  12. A white dwarf with an oxygen atmosphere.

    PubMed

    Kepler, S O; Koester, Detlev; Ourique, Gustavo

    2016-04-01

    Stars born with masses below around 10 solar masses end their lives as white dwarf stars. Their atmospheres are dominated by the lightest elements because gravitational diffusion brings the lightest element to the surface. We report the discovery of a white dwarf with an atmosphere completely dominated by oxygen, SDSS J124043.01+671034.68. After oxygen, the next most abundant elements in its atmosphere are neon and magnesium, but these are lower by a factor of ≥25 by number. The fact that no hydrogen or helium are observed is surprising. Oxygen, neon, and magnesium are the products of carbon burning, which occurs in stars at the high-mass end of pre-white dwarf formation. This star, a possible oxygen-neon white dwarf, will provide a rare observational test of the evolutionary paths toward white dwarfs.

  13. Evolution of the atmosphere and oceans.

    PubMed

    Holland, H D; Lazar, B; McCaffrey, M

    1986-03-06

    The residence times of most constituents of the atmosphere and oceans are small fractions of the age of the Earth and, in general, their rate of output has been nearly equal to their rate of input. We are disturbing a number of these dynamic equilibria quite severely. The mineralogy of marine evaporites rules out drastic changes in the composition of sea water during the last 900 Myr. The chemistry of soils formed more than 1,000 Myr ago suggests that the atmosphere then contained significantly more CO2 and less O2 than at present. Hydrogen peroxide may well have been the principal oxidant and formaldehyde the main reductant in rain water between 3,000 and 1,000 Myr ago. Major changes in atmospheric chemistry since that time are almost certainly related to the evolution of the biosphere.

  14. A white dwarf with an oxygen atmosphere

    NASA Astrophysics Data System (ADS)

    Kepler, S. O.; Koester, Detlev; Ourique, Gustavo

    2016-04-01

    Stars born with masses below around 10 solar masses end their lives as white dwarf stars. Their atmospheres are dominated by the lightest elements because gravitational diffusion brings the lightest element to the surface. We report the discovery of a white dwarf with an atmosphere completely dominated by oxygen, SDSS J124043.01+671034.68. After oxygen, the next most abundant elements in its atmosphere are neon and magnesium, but these are lower by a factor of ≥25 by number. The fact that no hydrogen or helium are observed is surprising. Oxygen, neon, and magnesium are the products of carbon burning, which occurs in stars at the high-mass end of pre-white dwarf formation. This star, a possible oxygen-neon white dwarf, will provide a rare observational test of the evolutionary paths toward white dwarfs.

  15. Fourteen Years of Atomic Hydrogen from SABER

    NASA Astrophysics Data System (ADS)

    Hunt, L. A.; Mlynczak, M. G.

    2015-12-01

    We present results for atomic hydrogen in the mesopause region (80-100 km) derived from measurements made by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the TIMED satellite. SABER has been measuring the vertical distribution of infrared radiation emitted by various atmospheric gases for nearly 14 years, providing important information about chemical species, including atomic oxygen, atomic hydrogen, ozone and hydroxyl; temperature; and the radiation budget in the upper atmosphere. The methodology for the derivation of daytime and nighttime concentrations and volume mixing ratios will be presented. Zonal mean and global average daytime and nighttime concentrations of H, which demonstrate excellent agreement between 87 and 95 km, have been calculated and the results are compared with observations from the Solar Mesosphere Explorer (SME) satellite made nearly 30 years ago. Variability over the course of the SABER mission will be shown, including the apparent inverse dependence on the solar cycle, which stems from the temperature dependence of various reaction rate coefficients for H photochemistry. Results for H near solar max will be compared for Solar Cycles 23 and 24.

  16. Photoelectrochemical hydrogen production

    SciTech Connect

    Rocheleau, R.E.; Miller, E.; Misra, A.

    1996-10-01

    The large-scale production of hydrogen utilizing energy provided by a renewable source to split water is one of the most ambitious long-term goals of the U.S. Department of Energy`s Hydrogen Program. One promising option to meet this goal is direct photoelectrolysis in which light absorbed by semiconductor-based photoelectrodes produces electrical power internally to split water into hydrogen and oxygen. Under this program, direct solar-to-chemical conversion efficiencies as high as 7.8 % have been demonstrated using low-cost, amorphous-silicon-based photoelectrodes. Detailed loss analysis models indicate that solar-to-chemical conversion greater than 10% can be achieved with amorphous-silicon-based structures optimized for hydrogen production. In this report, the authors describe the continuing progress in the development of thin-film catalytic/protective coatings, results of outdoor testing, and efforts to develop high efficiency, stable prototype systems.

  17. Hydrogen-fueled engine

    NASA Technical Reports Server (NTRS)

    Laumann, E. A.; Reynolds, R. K. (Inventor)

    1978-01-01

    A hydrogen-oxygen fueled internal combustion engine is described, which utilizes an inert gas, such as argon, as a working fluid to increase the efficiency of the engine, eliminate pollution, and facilitate operation of a closed cycle energy system. In a system where sunlight or other intermittent energy source is available to separate hydrogen and oxygen from water, the oxygen and inert gas are taken into a diesel engine into which hydrogen is injected and ignited. The exhaust is cooled so that it contains only water and the inert gas. The inert gas in the exhaust is returned to the engine for use with fresh oxygen, while the water in the exhaust is returned to the intermittent energy source for reconversion to hydrogen and oxygen.

  18. Thin film hydrogen sensor

    DOEpatents

    Lauf, R.J.; Hoffheins, B.S.; Fleming, P.H.

    1994-11-22

    A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed. 6 figs.

  19. Hydrogen storage compositions

    DOEpatents

    Li, Wen; Vajo, John J.; Cumberland, Robert W.; Liu, Ping

    2011-04-19

    Compositions for hydrogen storage and methods of making such compositions employ an alloy that exhibits reversible formation/deformation of BH.sub.4.sup.- anions. The composition includes a ternary alloy including magnesium, boron and a metal and a metal hydride. The ternary alloy and the metal hydride are present in an amount sufficient to render the composition capable of hydrogen storage. The molar ratio of the metal to magnesium and boron in the alloy is such that the alloy exhibits reversible formation/deformation of BH.sub.4.sup.- anions. The hydrogen storage composition is prepared by combining magnesium, boron and a metal to prepare a ternary alloy and combining the ternary alloy with a metal hydride to form the hydrogen storage composition.

  20. Remote hydrogen sensing techniques

    NASA Technical Reports Server (NTRS)

    Perry, Cortes L.

    1992-01-01

    The objective of this project is to evaluate remote hydrogen sensing methodologies utilizing metal oxide semi-conductor field effect transistors (MOS-FET) and mass spectrometric (MS) technologies and combinations thereof.

  1. Hydrogen chloride test set

    NASA Technical Reports Server (NTRS)

    Workman, G. L.

    1976-01-01

    Detector uses tertiary amine, which makes reaction fairly specific for relatively small highly polarized hydrogen chloride molecule. Reaction is monitored by any microbalance capable of measuring extremely small mass differences in real time.

  2. Florida Hydrogen Initiative

    SciTech Connect

    Block, David L

    2013-06-30

    The Florida Hydrogen Initiative (FHI) was a research, development and demonstration hydrogen and fuel cell program. The FHI program objectives were to develop Florida?s hydrogen and fuel cell infrastructure and to assist DOE in its hydrogen and fuel cell activities The FHI program funded 12 RD&D projects as follows: Hydrogen Refueling Infrastructure and Rental Car Strategies -- L. Lines, Rollins College This project analyzes strategies for Florida's early stage adaptation of hydrogen-powered public transportation. In particular, the report investigates urban and statewide network of refueling stations and the feasibility of establishing a hydrogen rental-car fleet based in Orlando. Methanol Fuel Cell Vehicle Charging Station at Florida Atlantic University ? M. Fuchs, EnerFuel, Inc. The project objectives were to design, and demonstrate a 10 kWnet proton exchange membrane fuel cell stationary power plant operating on methanol, to achieve an electrical energy efficiency of 32% and to demonstrate transient response time of less than 3 milliseconds. Assessment of Public Understanding of the Hydrogen Economy Through Science Center Exhibits, J. Newman, Orlando Science Center The project objective was to design and build an interactive Science Center exhibit called: ?H2Now: the Great Hydrogen Xchange?. On-site Reformation of Diesel Fuel for Hydrogen Fueling Station Applications ? A. Raissi, Florida Solar Energy Center This project developed an on-demand forecourt hydrogen production technology by catalytically converting high-sulfur hydrocarbon fuels to an essentially sulfur-free gas. The removal of sulfur from reformate is critical since most catalysts used for the steam reformation have limited sulfur tolerance. Chemochromic Hydrogen Leak Detectors for Safety Monitoring ? N. Mohajeri and N. Muradov, Florida Solar Energy Center This project developed and demonstrated a cost-effective and highly selective chemochromic (visual) hydrogen leak detector for safety monitoring

  3. Titan's hydrogen torus

    NASA Technical Reports Server (NTRS)

    Smyth, W. H.

    1981-01-01

    A model of Titan's hydrogen torus, capable of describing its time evolution under the influence of the gravitational fields of both the satellite and the planet, is presented. Estimated lifetimes for hydrogen atoms near Titan's orbit of the order of 10 to the 7th s, based on recent Pioneer 11 measurements, suggest that the torus completely encircles Saturn and is angularly unsymmetric, having an enhanced gas density near the satellite. New model calculations confirm this and provide an explanation for the torus detected by the Copernicus satellite and the UV instrument of Pioneer 11. Agreement between calculated and observed Lyman alpha intensities suggests a hydrogen escape flux between 1 x 10 to the 9th/sq cm-s and 3 x 10 to the 9th/sq cm-s should be operative at Titan. This produces a torus containing some 10 to the 34th hydrogen atoms.

  4. Hydrogen in titanium alloys

    SciTech Connect

    Wille, G W; Davis, J W

    1981-04-01

    The titanium alloys that offer properties worthy of consideration for fusion reactors are Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo-Si (Ti-6242S) and Ti-5Al-6Sn-2Zr-1Mo-Si (Ti-5621S). The Ti-6242S and Ti-5621S are being considered because of their high creep resistance at elevated temperatures of 500/sup 0/C. Also, irradiation tests on these alloys have shown irradiation creep properties comparable to 20% cold worked 316 stainless steel. These alloys would be susceptible to slow strain rate embrittlement if sufficient hydrogen concentrations are obtained. Concentrations greater than 250 to 500 wppm hydrogen and temperatures lower than 100 to 150/sup 0/C are approximate threshold conditions for detrimental effects on tensile properties. Indications are that at the elevated temperature - low hydrogen pressure conditions of the reactors, there would be negligible hydrogen embrittlement.

  5. Spectroscopy in the study of planetary atmospheres - Abundances from the visible region

    NASA Technical Reports Server (NTRS)

    Lutz, B. L.

    1978-01-01

    Spectrophotometric studies of three molecular constituents - hydrogen, methane, and ammonia - identified in the visible region of the spectra of the outer planets are reviewed. The history of quadrupole line observations for hydrogen molecules and the significance of the HD molecule for the dipole spectrum are considered. Approaches to quantitative estimates of methane concentration in planetary atmospheres are explained, and the detection of ammonia in the atmospheres of Jupiter and Saturn is described.

  6. The hydrogen issue.

    PubMed

    Armaroli, Nicola; Balzani, Vincenzo

    2011-01-17

    Hydrogen is often proposed as the fuel of the future, but the transformation from the present fossil fuel economy to a hydrogen economy will need the solution of numerous complex scientific and technological issues, which will require several decades to be accomplished. Hydrogen is not an alternative fuel, but an energy carrier that has to be produced by using energy, starting from hydrogen-rich compounds. Production from gasoline or natural gas does not offer any advantage over the direct use of such fuels. Production from coal by gasification techniques with capture and sequestration of CO₂ could be an interim solution. Water splitting by artificial photosynthesis, photobiological methods based on algae, and high temperatures obtained by nuclear or concentrated solar power plants are promising approaches, but still far from practical applications. In the next decades, the development of the hydrogen economy will most likely rely on water electrolysis by using enormous amounts of electric power, which in its turn has to be generated. Producing electricity by burning fossil fuels, of course, cannot be a rational solution. Hydroelectric power can give but a very modest contribution. Therefore, it will be necessary to generate large amounts of electric power by nuclear energy of by renewable energies. A hydrogen economy based on nuclear electricity would imply the construction of thousands of fission reactors, thereby magnifying all the problems related to the use of nuclear energy (e.g., safe disposal of radioactive waste, nuclear proliferation, plant decommissioning, uranium shortage). In principle, wind, photovoltaic, and concentrated solar power have the potential to produce enormous amounts of electric power, but, except for wind, such technologies are too underdeveloped and expensive to tackle such a big task in a short period of time. A full development of a hydrogen economy needs also improvement in hydrogen storage, transportation and distribution

  7. Transfer Hydrogenation in Water.

    PubMed

    Wu, Xiaofeng; Wang, Chao; Xiao, Jianliang

    2016-12-01

    This article provides an account of our group's efforts in developing aqueous-phase transfer hydrogenation reactions. It is comprised of mainly two parts. The first part concentrates on asymmetric transfer hydrogenation in water, enabled by Noyori-Ikariya catalysts, while the second part is concerned with the achiral version of the reaction catalysed by a new class of catalysts, iridacycles. A range of substrates are featured, including various carbonyl compounds and N-heterocycles.

  8. Interstellar hydrogen sulfide.

    NASA Technical Reports Server (NTRS)

    Thaddeus, P.; Kutner, M. L.; Penzias, A. A.; Wilson, R. W.; Jefferts, K. B.

    1972-01-01

    Hydrogen sulfide has been detected in seven Galactic sources by observation of a single line corresponding to the rotational transition from the 1(sub 10) to the 1(sub 01) levels at 168.7 GHz. The observations show that hydrogen sulfide is only a moderately common interstellar molecule comparable in abundance to H2CO and CS, but somewhat less abundant than HCN and much less abundant than CO.

  9. Method of producing hydrogen

    DOEpatents

    Bingham, Dennis N.; Klingler, Kerry M.; Wilding, Bruce M.; Zollinger, William T.

    2006-12-26

    A method of producing hydrogen is disclosed and which includes providing a first composition; providing a second composition; reacting the first and second compositions together to produce a chemical hydride; providing a liquid and reacting the chemical hydride with the liquid in a manner to produce a high pressure hydrogen gas and a byproduct which includes the first composition; and reusing the first composition formed as a byproduct in a subsequent chemical reaction to form additional chemical hydride.

  10. Cryogenic hydrogen release research.

    SciTech Connect

    LaFleur, Angela Christine

    2015-12-01

    The objective of this project was to devolop a plan for modifying the Turbulent Combustion Laboratory (TCL) with the necessary infrastructure to produce a cold (near liquid temperature) hydrogen jet. The necessary infrastructure has been specified and laboratory modifications are currently underway. Once complete, experiments from this platform will be used to develop and validate models that inform codes and standards which specify protection criteria for unintended releases from liquid hydrogen storage, transport, and delivery infrastructure.

  11. Advanced Hydrogen Liquefaction Process

    SciTech Connect

    Schwartz, Joseph; Kromer, Brian; Neu, Ben; Jankowiak, Jerome; Barrett, Philip; Drnevich, Raymond

    2011-09-28

    The project identified and quantified ways to reduce the cost of hydrogen liquefaction, and reduce the cost of hydrogen distribution. The goal was to reduce the power consumption by 20% and then to reduce the capital cost. Optimizing the process, improving process equipment, and improving ortho-para conversion significantly reduced the power consumption of liquefaction, but by less than 20%. Because the efficiency improvement was less than the target, the program was stopped before the capital cost was addressed. These efficiency improvements could provide a benefit to the public to improve the design of future hydrogen liquefiers. The project increased the understanding of hydrogen liquefaction by modeling different processes and thoroughly examining ortho-para separation and conversion. The process modeling provided a benefit to the public because the project incorporated para hydrogen into the process modeling software, so liquefaction processes can be modeled more accurately than using only normal hydrogen. Adding catalyst to the first heat exchanger, a simple method to reduce liquefaction power, was identified, analyzed, and quantified. The demonstrated performance of ortho-para separation is sufficient for at least one identified process concept to show reduced power cost when compared to hydrogen liquefaction processes using conventional ortho-para conversion. The impact of improved ortho-para conversion can be significant because ortho para conversion uses about 20-25% of the total liquefaction power, but performance improvement is necessary to realize a substantial benefit. Most of the energy used in liquefaction is for gas compression. Improvements in hydrogen compression will have a significant impact on overall liquefier efficiency. Improvements to turbines, heat exchangers, and other process equipment will have less impact.

  12. Hydrogen recovery process

    DOEpatents

    Baker, Richard W.; Lokhandwala, Kaaeid A.; He, Zhenjie; Pinnau, Ingo

    2000-01-01

    A treatment process for a hydrogen-containing off-gas stream from a refinery, petrochemical plant or the like. The process includes three separation steps: condensation, membrane separation and hydrocarbon fraction separation. The membrane separation step is characterized in that it is carried out under conditions at which the membrane exhibits a selectivity in favor of methane over hydrogen of at least about 2.5.

  13. Hydrogen Energy Conversion

    DTIC Science & Technology

    1976-07-27

    additional work has been done at Jet Propulsion Laboratory concerning the addition of hydrogen to gasoline . The continuing intent of the JPL program is to...extend the lean limits of combustion of gasoline by the addition of hydrogen generated from gasoline . As noted earlier (Ref. 13) and corroborated by...1) some additional , experimental data have been incorporated (particularly for cylinder-fuel-injected engines) and (2) the re- sults of

  14. Conductive dense hydrogen

    NASA Astrophysics Data System (ADS)

    Eremets, M.; Troyan, I.

    2012-12-01

    Hydrogen at ambient pressures and low temperatures forms a molecular crystal which is expected to display metallic properties under megabar pressures. This metal is predicted to be superconducting with a very high critical temperature Tc of 200-400 K. The superconductor may potentially be recovered metastably at ambient pressures, and it may acquire a new quantum state as a metallic superfluid and a superconducting superfluid. Recent experiments performed at low temperatures T < 100 K showed that at record pressures of 300 GPa, hydrogen remains in the molecular state and is an insulator with a band gap of appr 2 eV. Given our current experimental and theoretical understanding, hydrogen is expected to become metallic at pressures of 400-500 GPa, beyond the current limits of static pressures achievable using diamond anvil cells. We found that at room temperature and pressure > 220 GPa, new Raman modes arose, providing evidence for the transformation to a new opaque and electrically conductive phase IV. Above 260 GPa, in the next phase V, hydrogen reflected light well. Its resistance was nearly temperature-independent over a wide temperature range, down to 30 K, indicating that the hydrogen was metallic. Releasing the pressure induced the metallic phase to transform directly into molecular hydrogen with significant hysteresis at 200 GPa and 295 K. These data were published in our paper: M. I. Eremets and I. A. Troyan "Conductive dense hydrogen." Nature Materials 10: 927-931. We will present also new results on hydrogen: phase diagram with phases IV and V determined in P,T domain up to 300 GPa and 350 K. We will also discuss possible structures of phase IV based on our Raman and infrared measurements up to 300 GPa.

  15. Purdue Hydrogen Systems Laboratory

    SciTech Connect

    Jay P Gore; Robert Kramer; Timothee L Pourpoint; P. V. Ramachandran; Arvind Varma; Yuan Zheng

    2011-12-28

    The Hydrogen Systems Laboratory in a unique partnership between Purdue University's main campus in West Lafayette and the Calumet campus was established and its capabilities were enhanced towards technology demonstrators. The laboratory engaged in basic research in hydrogen production and storage and initiated engineering systems research with performance goals established as per the USDOE Hydrogen, Fuel Cells, and Infrastructure Technologies Program. In the chemical storage and recycling part of the project, we worked towards maximum recycling yield via novel chemical selection and novel recycling pathways. With the basic potential of a large hydrogen yield from AB, we used it as an example chemical but have also discovered its limitations. Further, we discovered alternate storage chemicals that appear to have advantages over AB. We improved the slurry hydrolysis approach by using advanced slurry/solution mixing techniques. We demonstrated vehicle scale aqueous and non-aqueous slurry reactors to address various engineering issues in on-board chemical hydrogen storage systems. We measured the thermal properties of raw and spent AB. Further, we conducted experiments to determine reaction mechanisms and kinetics of hydrothermolysis in hydride-rich solutions and slurries. We also developed a continuous flow reactor and a laboratory scale fuel cell power generation system. The biological hydrogen production work summarized as Task 4.0 below, included investigating optimal hydrogen production cultures for different substrates, reducing the water content in the substrate, and integrating results from vacuum tube solar collector based pre and post processing tests into an enhanced energy system model. An automated testing device was used to finalize optimal hydrogen production conditions using statistical procedures. A 3 L commercial fermentor (New Brunswick, BioFlo 115) was used to finalize testing of larger samples and to consider issues related to scale up. Efforts

  16. Hydrogen Delivery Technical Team Roadmap

    SciTech Connect

    2013-06-01

    The mission of the Hydrogen Delivery Technical Team (HDTT) is to enable the development of hydrogen delivery technologies, which will allow for fuel cell competitiveness with gasoline and hybrid technologies by achieving an as-produced, delivered, and dispensed hydrogen cost of $2-$4 per gallon of gasoline equivalent of hydrogen.

  17. Nanostructured materials for hydrogen storage

    DOEpatents

    Williamson, Andrew J.; Reboredo, Fernando A.

    2007-12-04

    A system for hydrogen storage comprising a porous nano-structured material with hydrogen absorbed on the surfaces of the porous nano-structured material. The system of hydrogen storage comprises absorbing hydrogen on the surfaces of a porous nano-structured semiconductor material.

  18. Examining hydrogen transitions.

    SciTech Connect

    Plotkin, S. E.; Energy Systems

    2007-03-01

    This report describes the results of an effort to identify key analytic issues associated with modeling a transition to hydrogen as a fuel for light duty vehicles, and using insights gained from this effort to suggest ways to improve ongoing modeling efforts. The study reported on here examined multiple hydrogen scenarios reported in the literature, identified modeling issues associated with those scenario analyses, and examined three DOE-sponsored hydrogen transition models in the context of those modeling issues. The three hydrogen transition models are HyTrans (contractor: Oak Ridge National Laboratory), MARKAL/DOE* (Brookhaven National Laboratory), and NEMS-H2 (OnLocation, Inc). The goals of these models are (1) to help DOE improve its R&D effort by identifying key technology and other roadblocks to a transition and testing its technical program goals to determine whether they are likely to lead to the market success of hydrogen technologies, (2) to evaluate alternative policies to promote a transition, and (3) to estimate the costs and benefits of alternative pathways to hydrogen development.

  19. STME Hydrogen Mixer Study

    NASA Technical Reports Server (NTRS)

    Blumenthal, Rob; Kim, Dongmoon; Bache, George

    1992-01-01

    The hydrogen mixer for the Space Transportation Main Engine is used to mix cold hydrogen bypass flow with warm hydrogen coolant chamber gas, which is then fed to the injectors. It is very important to have a uniform fuel temperature at the injectors in order to minimize mixture ratio problems due to the fuel density variations. In addition, the fuel at the injector has certain total pressure requirements. In order to achieve these objectives, the hydrogen mixer must provide a thoroughly mixed fluid with a minimum pressure loss. The AEROVISC computational fluid dynamics (CFD) code was used to analyze the STME hydrogen mixer, and proved to be an effective tool in optimizing the mixer design. AEROVISC, which solves the Reynolds Stress-Averaged Navier-Stokes equations in primitive variable form, was used to assess the effectiveness of different mixer designs. Through a parametric study of mixer design variables, an optimal design was selected which minimized mixed fuel temperature variation and fuel mixer pressure loss. The use of CFD in the design process of the STME hydrogen mixer was effective in achieving an optimal mixer design while reducing the amount of hardware testing.

  20. Electrochemical hydrogen Storage Systems

    SciTech Connect

    Dr. Digby Macdonald

    2010-08-09

    As the global need for energy increases, scientists and engineers have found a possible solution by using hydrogen to power our world. Although hydrogen can be combusted as a fuel, it is considered an energy carrier for use in fuel cells wherein it is consumed (oxidized) without the production of greenhouse gases and produces electrical energy with high efficiency. Chemical storage of hydrogen involves release of hydrogen in a controlled manner from materials in which the hydrogen is covalently bound. Sodium borohydride and aminoborane are two materials given consideration as chemical hydrogen storage materials by the US Department of Energy. A very significant barrier to adoption of these materials as hydrogen carriers is their regeneration from 'spent fuel,' i.e., the material remaining after discharge of hydrogen. The U.S. Department of Energy (DOE) formed a Center of Excellence for Chemical Hydrogen Storage, and this work stems from that project. The DOE has identified boron hydrides as being the main compounds of interest as hydrogen storage materials. The various boron hydrides are then oxidized to release their hydrogen, thereby forming a 'spent fuel' in the form of a lower boron hydride or even a boron oxide. The ultimate goal of this project is to take the oxidized boron hydrides as the spent fuel and hydrogenate them back to their original form so they can be used again as a fuel. Thus this research is essentially a boron hydride recycling project. In this report, research directed at regeneration of sodium borohydride and aminoborane is described. For sodium borohydride, electrochemical reduction of boric acid and sodium metaborate (representing spent fuel) in alkaline, aqueous solution has been investigated. Similarly to literature reports (primarily patents), a variety of cathode materials were tried in these experiments. Additionally, approaches directed at overcoming electrostatic repulsion of borate anion from the cathode, not described in the

  1. Hydrogen Sorption and Transport

    NASA Astrophysics Data System (ADS)

    McNeece, C. J.; Hesse, M. A.

    2015-12-01

    Hydrogen is unique among aqueous ions, both in its importance for geochemical reactions, and in its complex transport behavior through reactive media. The structure of hydrogen reaction fronts can be analyzed in the advective limit of the transport equation. At local chemical equilibrium, sorption of hydrogen onto the media surface (sorption isotherm) controls reaction front morphology. Transport modeling thus necessitates accurate knowledge of surface chemistry. Though motivated by transport, sorption models are often parameterized against batch titration experiments. The validity of these parameterizations, in a transport setting, are seldom tested. The analytic solution to the transport equation gives an algebraic relationship between concentration velocity and equilibrium sorption behavior. In this study, we conduct a suite of column flow experiments through quartz sand. Hydrogen concentration breakthrough curves at the column outlet are used to infer the "transport sorption isotherm." These results are compared to the batch titration derived sorption isotherm. We find excellent agreement between the datasets. Our findings suggest that, for aqueous hydrogen, local chemical equilibrium is a valid assumption. With the goal of a predictive transport model, we parameterize various sorption models against this dataset. Models which incorporate electrostatic effects at the surface predict transport well. Nonelectrostatic models such as the Kd, Langmuir, and Freundlich models fail. These results are particularly compelling as nonelectrostatic models are often employed to predict hydrogen transport in many reactive transport code.

  2. Hydrogen multicentre bonds.

    PubMed

    Janotti, Anderson; Van de Walle, Chris G

    2007-01-01

    The concept of a chemical bond stands out as a major development in the process of understanding how atoms are held together in molecules and solids. Lewis' classical picture of chemical bonds as shared-electron pairs evolved to the quantum-mechanical valence-bond and molecular-orbital theories, and the classification of molecules and solids in terms of their bonding type: covalent, ionic, van der Waals and metallic. Along with the more complex hydrogen bonds and three-centre bonds, they form a paradigm within which the structure of almost all molecules and solids can be understood. Here, we present evidence for hydrogen multicentre bonds-a generalization of three-centre bonds-in which a hydrogen atom equally bonds to four or more other atoms. When substituting for oxygen in metal oxides, hydrogen bonds equally to all the surrounding metal atoms, becoming fourfold coordinated in ZnO, and sixfold coordinated in MgO. These multicentre bonds are remarkably strong despite their large hydrogen-metal distances. The calculated local vibration mode frequency in MgO agrees with infrared spectroscopy measurements. Multicoordinated hydrogen also explains the dependence of electrical conductivity on oxygen partial pressure, resolving a long-standing controversy on the role of point defects in unintentional n-type conductivity of ZnO (refs 8-10).

  3. Improved Screened Hydrogenic Model

    SciTech Connect

    Nishikawa, T.

    1996-05-01

    Screened Hydrogenic Model is widely used for energy level calculation in hydrodynamic code of inertial confinement fusion because Screened Hydrogenic Model is simple algebraic calculation. More{close_quote}s Screened Hydrogenic Model and his screening constants are usually used to calculate opacity and equation of state. By the use of his model, energy level can be consistently calculated with ion{close_quote}s total energy. But his model take into account the principal quantum number dependence only and cannot reproduce hydrogenic energy levels. As the precise experiment about opacity measurement is performed, it becomes clear that his model is not enough to use for opacity calculation. In this paper, his model is improved in the framework of Screened Hydrogenic Model. The improved model can reproduce the hydrogenic energy levels and include azimuthal quantum number dependence and the effect from another quantum state (a kind of inner quantum number). Screening constants are fitted by spectroscopic data and sophisticate calculations. By the use of improved model, energy levels are calculated more accurately for low-{ital z} ions. {copyright} {ital 1996 American Institute of Physics.}

  4. Membrane-less hydrogen bromine flow battery.

    PubMed

    Braff, William A; Bazant, Martin Z; Buie, Cullen R

    2013-01-01

    In order for the widely discussed benefits of flow batteries for electrochemical energy storage to be applied at large scale, the cost of the electrochemical stack must come down substantially. One promising avenue for reducing stack cost is to increase the system power density while maintaining efficiency, enabling smaller stacks. Here we report on a membrane-less hydrogen bromine laminar flow battery as a potential high-power density solution. The membrane-less design enables power densities of 0.795 W cm(-2) at room temperature and atmospheric pressure, with a round-trip voltage efficiency of 92% at 25% of peak power. Theoretical solutions are also presented to guide the design of future laminar flow batteries. The high-power density achieved by the hydrogen bromine laminar flow battery, along with the potential for rechargeable operation, will translate into smaller, inexpensive systems that could revolutionize the fields of large-scale energy storage and portable power systems.

  5. Germanium detector passivated with hydrogenated amorphous germanium

    DOEpatents

    Hansen, William L.; Haller, Eugene E.

    1986-01-01

    Passivation of predominantly crystalline semiconductor devices (12) is provided for by a surface coating (21) of sputtered hydrogenated amorphous semiconductor material. Passivation of a radiation detector germanium diode, for example, is realized by sputtering a coating (21) of amorphous germanium onto the etched and quenched diode surface (11) in a low pressure atmosphere of hydrogen and argon. Unlike prior germanium diode semiconductor devices (12), which must be maintained in vacuum at cryogenic temperatures to avoid deterioration, a diode processed in the described manner may be stored in air at room temperature or otherwise exposed to a variety of environmental conditions. The coating (21) compensates for pre-existing undesirable surface states as well as protecting the semiconductor device (12) against future impregnation with impurities.

  6. Hydrogen in hot subdwarfs formed by double helium white dwarf mergers

    NASA Astrophysics Data System (ADS)

    Hall, Philip D.; Jeffery, C. Simon

    2016-12-01

    Isolated hot subdwarfs might be formed by the merging of two helium-core white dwarfs. Before merging, helium-core white dwarfs have hydrogen-rich envelopes and some of this hydrogen may survive the merger. We calculate the mass of hydrogen that is present at the start of such mergers and, with the assumption that hydrogen is mixed throughout the disrupted white dwarf in the merger process, estimate how much can survive. We find a hydrogen mass of up to about 2 × 10-3 M⊙ in merger remnants. We make model merger remnants that include the hydrogen mass appropriate to their total mass and compare their atmospheric parameters with a sample of apparently isolated hot subdwarfs, hydrogen-rich sdBs. The majority of these stars can be explained as the remnants of double helium white dwarf mergers.

  7. Hydrogen Generation Via Sodium Borohydride

    NASA Astrophysics Data System (ADS)

    Mohring, Richard M.; Wu, Ying

    2003-07-01

    Along with the technological challenges associated with developing fuel cells and hydrogen burning engines, a major issue that must be addressed to ensure the ultimate success of a hydrogen economy is the ability to store and transport hydrogen effectively. Millennium Cell has developed and patented a proprietary system for storing and generating hydrogen gas called Hydrogen on Demand™. The system releases the hydrogen stored in fuel solutions of sodium borohydride as needed through an easily controllable catalytic process. The fuel itself is water-based, rich in hydrogen content, and non-flammable. It can be stored in plastic containers under no pressure. After the hydrogen from the fuel is consumed, the remaining product, sodium metaborate (chemically similar to borax), can be recycled back into fresh fuel. In this paper, an overview of the Hydrogen on Demand™ technology is presented along with data showing the performance characteristics of practical hydrogen generation systems. A brief discussion of sodium borohydride regeneration chemistry is also provided.

  8. Stellar atmospheric structural patterns

    NASA Technical Reports Server (NTRS)

    Thomas, R. N.

    1983-01-01

    The thermodynamics of stellar atmospheres is discussed. Particular attention is given to the relation between theoretical modeling and empirical evidence. The characteristics of distinctive atmospheric regions and their radical structures are discussed.

  9. Earth's changeable atmosphere

    NASA Astrophysics Data System (ADS)

    2016-06-01

    Billions of years ago, high atmospheric greenhouse gas concentrations were vital to life's tenuous foothold on Earth. Despite new constraints, the composition and evolution of Earth's early atmosphere remains hazy.

  10. The Atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Hansen, J. E. (Editor)

    1975-01-01

    Topics considered at the conference included the dynamics, structure, chemistry, and evolution of the Venus atmosphere, as well as cloud physics and motion. Infrared, ultraviolet, and radio occultation methods of analysis are discussed, and atmospheric models are described.

  11. Uranus' Upper Atmosphere

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This computer enhancement of a Voyager 2 image, emphasizes the high-level haze in Uranus' upper atmosphere. Clouds are obscured by the overlying atmosphere.

    JPL manages and controls the Voyager project for NASA's Office of Space Science.

  12. Our shared atmosphere

    EPA Science Inventory

    Our atmosphere is a precious and fascinating resource, providing air to breath, shielding us from harmful ultraviolet radiation (UV), and maintaining a comfortable climate. Since the industrial revolution, people have significantly altered the composition of the atmosphere throu...

  13. California Hydrogen Infrastructure Project

    SciTech Connect

    Heydorn, Edward C

    2013-03-12

    Air Products and Chemicals, Inc. has completed a comprehensive, multiyear project to demonstrate a hydrogen infrastructure in California. The specific primary objective of the project was to demonstrate a model of a real-world retail hydrogen infrastructure and acquire sufficient data within the project to assess the feasibility of achieving the nation's hydrogen infrastructure goals. The project helped to advance hydrogen station technology, including the vehicle-to-station fueling interface, through consumer experiences and feedback. By encompassing a variety of fuel cell vehicles, customer profiles and fueling experiences, this project was able to obtain a complete portrait of real market needs. The project also opened its stations to other qualified vehicle providers at the appropriate time to promote widespread use and gain even broader public understanding of a hydrogen infrastructure. The project engaged major energy companies to provide a fueling experience similar to traditional gasoline station sites to foster public acceptance of hydrogen. Work over the course of the project was focused in multiple areas. With respect to the equipment needed, technical design specifications (including both safety and operational considerations) were written, reviewed, and finalized. After finalizing individual equipment designs, complete station designs were started including process flow diagrams and systems safety reviews. Material quotes were obtained, and in some cases, depending on the project status and the lead time, equipment was placed on order and fabrication began. Consideration was given for expected vehicle usage and station capacity, standard features needed, and the ability to upgrade the station at a later date. In parallel with work on the equipment, discussions were started with various vehicle manufacturers to identify vehicle demand (short- and long-term needs). Discussions included identifying potential areas most suited for hydrogen fueling stations

  14. Improved Hydrogen Gas Getters for TRU Waste -- Final Report

    SciTech Connect

    Mark Stone; Michael Benson; Christopher Orme; Thomas Luther; Eric Peterson

    2005-09-01

    Alpha radiolysis of hydrogenous waste and packaging materials generates hydrogen gas in radioactive storage containers. For that reason, the Nuclear Regulatory Commission limits the flammable gas (hydrogen) concentration in the Transuranic Package Transporter-II (TRUPACT-II) containers to 5 vol% of hydrogen in air, which is the lower explosion limit. Consequently, a method is needed to prevent the build up of hydrogen to 5 vol% during the storage and transport of the TRUPACT-II containers (up to 60 days). One promising option is the use of hydrogen getters. These materials scavenge hydrogen from the gas phase and irreversibly bind it in the solid phase. One proven getter is a material called 1,4-bis (phenylethynyl) benzene, or DEB, characterized by the presence of carbon-carbon triple bonds. Carbon may, in the presence of suitable precious metal catalysts such as palladium, irreversibly react with and bind hydrogen. In the presence of oxygen, the precious metal may also eliminate hydrogen by catalyzing the formation of water. This reaction is called catalytic recombination. DEB has the needed binding rate and capacity for hydrogen that potentially could be generated in the TRUPACT II. Phases 1 and 2 of this project showed that uncoated DEB performed satisfactorily in lab scale tests. Based upon these results, Phase 3, the final project phase, included larger scale testing. Test vessels were scaled to replicate the ratio between void space in the inner containment vessel of a TRUPACT-II container and a payload of seven 55-gallon drums. The tests were run with an atmosphere of air for 63.9 days at ambient temperature (15-27°C) and a scaled hydrogen generation rate of 2.60E-07 moles per second (0.35 cc/min). A second type of getter known as VEI, a proprietary polymer hydrogen getter characterized by carbon-carbon double bonds, was also tested in Phase 3. Hydrogen was successfully “gettered” by both getter systems. Hydrogen concentrations remained below 5 vol% (in

  15. Hydrogen storage and generation system

    DOEpatents

    Dentinger, Paul M.; Crowell, Jeffrey A. W.

    2010-08-24

    A system for storing and generating hydrogen generally and, in particular, a system for storing and generating hydrogen for use in an H.sub.2/O.sub.2 fuel cell. The hydrogen storage system uses the beta particles from a beta particle emitting material to degrade an organic polymer material to release substantially pure hydrogen. In a preferred embodiment of the invention, beta particles from .sup.63Ni are used to release hydrogen from linear polyethylene.

  16. Shuttle Gaseous Hydrogen Venting Risk from Flow Control Valve Failure

    NASA Technical Reports Server (NTRS)

    Drummond, J. Philip; Baurle, Robert A.; Gafney, Richard L.; Norris, Andrew T.; Pellett, Gerald L.; Rock, Kenneth E.

    2009-01-01

    This paper describes a series of studies to assess the potential risk associated with the failure of one of three gaseous hydrogen flow control valves in the orbiter's main propulsion system during the launch of Shuttle Endeavour (STS-126) in November 2008. The studies focused on critical issues associated with the possibility of combustion resulting from release of gaseous hydrogen from the external tank into the atmosphere during assent. The Shuttle Program currently assumes hydrogen venting from the external tank will result in a critical failure. The current effort was conducted to increase understanding of the risk associated with venting hydrogen given the flow control valve failure scenarios being considered in the Integrated In-Flight Anomaly Investigation being conducted by NASA.

  17. Sea water for hydrogen and for municipal use

    NASA Astrophysics Data System (ADS)

    Lodhi, M. A. K.

    The production of hydrogen from sea water using solar energy is discussed, and a set of parameters for the project is worked out. The energy produced by electrolysis is directly proportional to the rate of evaporation. If the water is collected in a sink reservoir from the sea and solar energy is used directly to produce hydrogen, the evaporation rate will increase and more hydraulic energy will be available. The end-product of hydrogen electrolysis is fresh water, which can be used for domestic, industrial, or agricultural purposes. Letting this water evaporate into the atmosphere might increase the humidity and lead to some environmental hazards. The cost of hydrogen production is currently greater than that of other conventional energies, despite its low transportation and distribution costs.

  18. Identification of hydrogen molecules in ZnO.

    PubMed

    Lavrov, E V; Herklotz, F; Weber, J

    2009-05-08

    Hydrogen molecules in ZnO are identified by their local vibrational modes. In a Raman study, interstitial H2, HD, and D2 species were found to exhibit local vibrational modes at frequencies 4145, 3628, and 2985 cm-1, respectively. After thermal treatment of vapor phase grown ZnO samples in hydrogen atmosphere, most hydrogen forms shallow donors at the bond-centered site (HBC). Subsequently, HBC migrates through the crystal and forms electrically inactive H2. These results imply that the "hidden" hydrogen in ZnO [G. A. Shi et al., Appl. Phys. Lett. 85, 5601 (2004)10.1063/1.1832736] occurs in the form of interstitial H2.

  19. The atmosphere of Jupiter

    NASA Technical Reports Server (NTRS)

    Ingersoll, A. P.

    1976-01-01

    Current information on the neutral atmosphere of Jupiter is reviewed, with approximately equal emphasis on composition and thermal structure on one hand, and markings and dynamics on the other. Studies based on Pioneer 10 and 11 data are used to refine the atmospheric model. Data on the interior are reviewed for the information they provide on the deep atmosphere. The markings and dynamics are discussed with emphasis on qualitative relationships and analogies with phenomena in earth's atmosphere.

  20. Atmospheric Nitrogen Fluorescence Yield

    NASA Technical Reports Server (NTRS)

    Adams, J. H., Jr.; Christl, M. J.; Fountain, W. F.; Gregory, J. C.; Martens, K. U.; Sokolsky, Pierre; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Several existing and planned experiments estimate the energies of ultra-high energy cosmic rays from air showers using the atmospheric nitrogen fluorescence. The nitrogen fluorescence yield from air shower electrons depends on the atmospheric composition. We will discuss the uncertainties in the fluorescence yield form electrons in the real atmosphere and describe a concept for a small balloon payload to measure the atmospheric fluorescence yield as a function of attitude.