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Sample records for high temperature hydrogenated

  1. High Temperature Decomposition of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydropemxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  2. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2005-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  3. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2011-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  4. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  5. High temperature inorganic membranes for separating hydrogen

    SciTech Connect

    Fain, D.E.; Roettger, G.E.

    1995-08-01

    Effort has continued to accumulate data on the transport of gases over the temperature range from room temperature to 275{degrees}C with inorganic membranes having a range of pore radii from approximately 0.25 nm to 3 mn. An experimental alumina membrane having an estimated mean pore radius of 0.25 nm has been fabricated and tested. Extensive testing of this membrane indicated that the separation factor for helium and carbon tetrafluoride at 250{degrees}C was 59 and the extrapolated high temperature separation factor was 1,193. For safety reasons, earlier flow measurements concentrated on helium, carbon dioxide, and carbon tetrafluoride. New data have been acquired with hydrogen to verify the agreement with the other gases. During the measurements with hydrogen, it was noted that a considerable amount of moisture was present in the test gas. The source of this moisture and its effect on permeance was examined. Improvements were implemented to the flow test system to minimize the water content of the hydrogen test gas, and subsequent flow measurements have shown excellent results with hydrogen. The extrapolation of separation factors as a function of temperature continues to show promise as a means of using the hard sphere model to determine the pore size of membranes. The temperature dependence of helium transport through membranes appears to be considerably greater than other gases for the smallest pore sizes. The effort to extend temperature dependence to the hard sphere model continues to be delayed, primarily because of a lack of adequate adsorption data.

  6. Hydrogen Production from Nuclear Energy via High Temperature Electrolysis

    SciTech Connect

    James E. O'Brien; Carl M. Stoots; J. Stephen Herring; Grant L. Hawkes

    2006-04-01

    This paper presents the technical case for high-temperature nuclear hydrogen production. A general thermodynamic analysis of hydrogen production based on high-temperature thermal water splitting processes is presented. Specific details of hydrogen production based on high-temperature electrolysis are also provided, including results of recent experiments performed at the Idaho National Laboratory. Based on these results, high-temperature electrolysis appears to be a promising technology for efficient large-scale hydrogen production.

  7. High temperature regenerable hydrogen sulfide removal agents

    DOEpatents

    Copeland, Robert J.

    1993-01-01

    A system for high temperature desulfurization of coal-derived gases using regenerable sorbents. One sorbent is stannic oxide (tin oxide, SnO.sub.2), the other sorbent is a metal oxide or mixed metal oxide such as zinc ferrite (ZnFe.sub.2 O.sub.4). Certain otherwise undesirable by-products, including hydrogen sulfide (H.sub.2 S) and sulfur dioxide (SO.sub.2) are reused by the system, and elemental sulfur is produced in the regeneration reaction. A system for refabricating the sorbent pellets is also described.

  8. Ceramic membranes for high temperature hydrogen separation

    SciTech Connect

    Fain, D.E.; Roettger, G.E.

    1996-08-01

    Ceramic gas separation membranes can provide very high separation factors if the pore size is sufficiently small to separate gas molecules by molecular sieving and if oversized pores are adequately limited. Ceramic membranes typically have some pores that are substantially larger than the mean pore size and that should be regarded as defects. To assess the effects of such defects on the performance of ceramic membranes, a simple mathematical model has been developed to describe flow through a gas separation membrane that has a primary mode of flow through very small pores but that has a secondary mode of flow through undesirably large pores. This model permits separation factors to be calculated for a specified gas pair as a function of the molecular weights and molecular diameters of the gases, the membrane pore diameter, and the diameter and number of defects. This model will be described, and key results from the model will be presented. The separation factors of the authors membranes continue to be determined using a permeance test system that measures flows of pure gases through a membrane at temperatures up to 275{degrees}C. A primary goal of this project for FY 1996 is to develop a mixed gas separation system for measuring the separation efficiency of membranes at higher temperatures. Performance criteria have been established for the planned mixed gas separation system and design of the system has been completed. The test system is designed to measure the separation efficiency of membranes at temperatures up to 600{degrees}C and pressures up to 100 psi by separating the constituents of a gas mixture containing hydrogen. The system will accommodate the authors typical experimental membrane that is tubular and has a diameter of about 9 mm and a length of about 23 cm. The design of the new test system and its expected performance will be discussed.

  9. Ceramic membranes for high temperature hydrogen separation

    SciTech Connect

    Adcock, K.D.; Fain, D.E.; James, D.L.; Powell, L.E.; Raj, T.; Roettger, G.E.; Sutton, T.G.

    1997-12-01

    The separative performance of the authors` ceramic membranes has been determined in the past using a permeance test system that measured flows of pure gases through a membrane at temperatures up to 275 C. From these data, the separation factor was determined for a particular gas pair from the ratio of the pure gas specific flows. An important project goal this year has been to build a Mixed Gas Separation System (MGSS) for measuring the separation efficiencies of membranes at higher temperatures and using mixed gases. The MGSS test system has been built, and initial operation has been achieved. The MGSS is capable of measuring the separation efficiency of membranes at temperatures up to 600 C and pressures up to 100 psi using a binary gas mixture such as hydrogen/methane. The mixed gas is fed into a tubular membrane at pressures up to 100 psi, and the membrane separates the feed gas mixture into a permeate stream and a raffinate stream. The test membrane is sealed in a stainless steel holder that is mounted in a split tube furnace to permit membrane separations to be evaluated at temperatures up to 600 C. The compositions of the three gas streams are measured by a gas chromatograph equipped with thermal conductivity detectors. The test system also measures the temperatures and pressures of all three gas streams as well as the flow rate of the feed stream. These data taken over a range of flows and pressures permit the separation efficiency to be determined as a function of the operating conditions. A mathematical model of the separation has been developed that permits the data to be reduced and the separation factor for the membrane to be determined.

  10. Reduced hydrogen permeability at high temperatures

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Klopp, W. D.; Misencik, J. A.

    1981-01-01

    CO and CO2 reduce hydrogen loss through iron, nickel, and cobalt based alloy tubes. Method is based on concept that oxide film on metal surface reduces hydrogen permeability through metal; adding CO or CO2 forms oxide films continuously during operation, and hydrogen containment is improved. Innovation enhances prospects for Stirling engine system utilization.

  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. High temperature equation of state of metallic hydrogen

    SciTech Connect

    Shvets, V. T.

    2007-04-15

    The equation of state of liquid metallic hydrogen is solved numerically. Investigations are carried out at temperatures from 3000 to 20 000 K and densities from 0.2 to 3 mol/cm{sup 3}, which correspond both to the experimental conditions under which metallic hydrogen is produced on earth and the conditions in the cores of giant planets of the solar system such as Jupiter and Saturn. It is assumed that hydrogen is in an atomic state and all its electrons are collectivized. Perturbation theory in the electron-proton interaction is applied to determine the thermodynamic potentials of metallic hydrogen. The electron subsystem is considered in the randomphase approximation with regard to the exchange interaction and the correlation of electrons in the local-field approximation. The proton-proton interaction is taken into account in the hard-spheres approximation. The thermodynamic characteristics of metallic hydrogen are calculated with regard to the zero-, second-, and third-order perturbation theory terms. The third-order term proves to be rather essential at moderately high temperatures and densities, although it is much smaller than the second-order term. The thermodynamic potentials of metallic hydrogen are monotonically increasing functions of density and temperature. The values of pressure for the temperatures and pressures that are characteristic of the conditions under which metallic hydrogen is produced on earth coincide with the corresponding values reported by the discoverers of metallic hydrogen to a high degree of accuracy. The temperature and density ranges are found in which there exists a liquid phase of metallic hydrogen.

  14. High temperature ceramic composition for hydrogen retention

    DOEpatents

    Webb, R.W.

    1974-01-01

    A ceramic coating for H retention in fuel elements is described. The coating has relatively low thermal neutron cross section, is not readily reduced by H at 1500 deg F, is adherent to the fuel element base metal, and is stable at reactor operating temperatures. (JRD)

  15. Materials for the scavenging of hydrogen at high temperatures

    DOEpatents

    Shepodd, T.J.; Phillip, B.L.

    1997-04-29

    A hydrogen getter composition is described 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 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 fluoropolymers, 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. 7 figs.

  16. Materials for the scavenging of hydrogen at high temperatures

    DOEpatents

    Shepodd, T.J.; Phillip, B.L.

    1997-12-30

    A hydrogen getter composition is described 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 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 fluoropolymers, 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. 7 figs.

  17. ANALYSIS OF A HIGH TEMPERATURE GAS-COOLED REACTOR POWERED HIGH TEMPERATURE ELECTROLYSIS HYDROGEN PLANT

    SciTech Connect

    M. G. McKellar; E. A. Harvego; A. M. Gandrik

    2010-11-01

    An updated reference design for a commercial-scale high-temperature electrolysis (HTE) plant for hydrogen production has been developed. The HTE plant is powered by a high-temperature gas-cooled reactor (HTGR) whose configuration and operating conditions are based on the latest design parameters planned for the Next Generation Nuclear Plant (NGNP). The current HTGR reference design specifies a reactor power of 600 MWt, with a primary system pressure of 7.0 MPa, and reactor inlet and outlet fluid temperatures of 322°C and 750°C, respectively. The reactor heat is used to produce heat and electric power to the HTE plant. A Rankine steam cycle with a power conversion efficiency of 44.4% was used to provide the electric power. The electrolysis unit used to produce hydrogen includes 1.1 million cells with a per-cell active area of 225 cm2. The reference hydrogen production plant operates at a system pressure of 5.0 MPa, and utilizes a steam-sweep system to remove the excess oxygen that is evolved on the anode (oxygen) side of the electrolyzer. The overall system thermal-to-hydrogen production efficiency (based on the higher heating value of the produced hydrogen) is 42.8% at a hydrogen production rate of 1.85 kg/s (66 million SCFD) and an oxygen production rate of 14.6 kg/s (33 million SCFD). An economic analysis of this plant was performed with realistic financial and cost estimating The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a competitive cost. A cost of $3.03/kg of hydrogen was calculated assuming an internal rate of return of 10% and a debt to equity ratio of 80%/20% for a reactor cost of $2000/kWt and $2.41/kg of hydrogen for a reactor cost of $1400/kWt.

  18. Hydrogen diffusion in high temperature proton conducting ceramics

    NASA Astrophysics Data System (ADS)

    Sorieul, S.; Miro, S.; Taillades-Jacquin, M.; Dailly, J.; Mauvy, F.; Berger, M.-H.; Berger, P.

    2008-04-01

    BaCeO3 or SrCeO3-based perovskites doped with a rare earth are high temperature protonic conductors (HTPC) envisioned as electrolytes for fuel cells working at intermediate temperature (400-600 °C). In these ceramics, the proton conductance is hampered by microstructural defects that act as barriers for hydrogen diffusion. Respective contributions of bulk and grain boundaries to overall conductivity is usually evidenced via impedance measurements but further information on hydrogen transport relevant for improvement of microstructure design can be obtained with nuclear microanalysis, based on the use of MeV light ions microbeam. We report here a contribution of ion beam microanalysis to the study of hydrogen transport in BaCe0.9Y0.1O3. ERDA hydrogen profiling performed on partially hydrated samples at 200 and 500 °C reveals concentration gradients from which diffusion coefficients have been derived with the help of a simple Fickian diffusion model.

  19. Overview of High-Temperature Electrolysis for Hydrogen Production

    SciTech Connect

    Herring, J. S.; O'Brien, J. E.; Stoots, C. M.; Hartvigsen, J. J.; Petri, M. C.; Carter, J. D.; Bischoff, B. L.

    2007-06-01

    Over the last five years there has been a growing interest in the use of hydrogen as an energy carrier, particularly to augment transportation fuels and thus reduce our dependence on imported petroleum. Hydrogen is now produced primarily via steam reforming of methane. However, in the long term, methane reforming is not a viable process for the large-scale hydrogen production since such fossil fuel conversion processes consume non-renewable resources and emit greenhouse gases. Nuclear energy can be used to produce hydrogen without consuming fossil fuels and without emitting greenhouse gases through the splitting of water into hydrogen and oxygen. The Nuclear Hydrogen Initiative of the DOE Office of Nuclear Energy is developing three general categories of high temperature processes for hydrogen production: thermochemical, electrolytic and hybrid thermo-electrolytic. This paper introduces the work being done in the development of high temperature electrolysis of steam. High Temperature Electrolysis (HTE) is built on the technology of solid oxide fuel cells (SOFCs), which were invented over a century ago, but which have been most vigorously developed during the last twenty years. SOFCs consume hydrogen and oxygen and produce steam and electricity. Solid Oxide Electrolytic Cells (SOECs) consume electricity and steam and produce hydrogen and oxygen. The purpose of the HTE research is to solve those problems unique to the electrolytic mode of operation, while building further on continuing fuel cell development. ORGANIZATION Experiments have been conducted for the last three years at the Idaho National Laboratory and at Ceramatec, Inc. on the operation of button cells and of progressively larger stacks of planar cells. In addition, the INL has been performing analyses of the cell-scale fluid dynamics and plant-scale flowsheets in order to determine optimum operating conditions and plant configurations. Argonne National Laboratory has been performing experiments for the

  20. High-temperature study of superconducting hydrogen and deuterium sulfide

    NASA Astrophysics Data System (ADS)

    Durajski, A. P.; Szczȩśniak, R.; Pietronero, L.

    2016-05-01

    Hydrogen-rich compounds are extensively explored as candidates for a high-temperature superconductors. Currently, the measured critical temperature of $203$ K in hydrogen sulfide (H$_3$S) is among the highest over all-known superconductors. In present paper, using the strong-coupling Eliashberg theory of superconductivity, we compared in detail the thermodynamic properties of two samples containing different hydrogen isotopes H$_3$S and D$_3$S at $150$ GPa. Our research indicates that it is possible to reproduce the measured values of critical temperature $203$ K and $147$ K for H$_3$S and D$_3$S by using a Coulomb pseudopotential of $0.123$ and $0.131$, respectively. However, we also discuss a scenario in which the isotope effect is independent of pressure and the Coulomb pseudopotential for D$_3$S is smaller than for H$_3$S. For both scenarios, the energy gap, specific heat, thermodynamic critical field and related dimensionless ratios are calculated and compared with other conventional superconductors. We shown that the existence of the strong-coupling and retardation effects in the systems analysed result in significant differences between values obtained within the framework of the Eliashberg formalism and the prediction of the Bardeen-Cooper-Schrieffer theory.

  1. Amorphous Alloy Membranes for High Temperature Hydrogen Separation

    SciTech Connect

    Coulter, K

    2013-09-30

    At the beginning of this project, thin film amorphous alloy membranes were considered a nascent but promising new technology for industrial-scale hydrogen gas separations from coal- derived syngas. This project used a combination of theoretical modeling, advanced physical vapor deposition fabricating, and laboratory and gasifier testing to develop amorphous alloy membranes that had the potential to meet Department of Energy (DOE) targets in the testing strategies outlined in the NETL Membrane Test Protocol. The project is complete with Southwest Research Institute® (SwRI®), Georgia Institute of Technology (GT), and Western Research Institute (WRI) having all operated independently and concurrently. GT studied the hydrogen transport properties of several amorphous alloys and found that ZrCu and ZrCuTi were the most promising candidates. GT also evaluated the hydrogen transport properties of V, Nb and Ta membranes coated with different transition-metal carbides (TMCs) (TM = Ti, Hf, Zr) catalytic layers by employing first-principles calculations together with statistical mechanics methods and determined that TiC was the most promising material to provide catalytic hydrogen dissociation. SwRI developed magnetron coating techniques to deposit a range of amorphous alloys onto both porous discs and tubular substrates. Unfortunately none of the amorphous alloys could be deposited without pinhole defects that undermined the selectivity of the membranes. WRI tested the thermal properties of the ZrCu and ZrNi alloys and found that under reducing environments the upper temperature limit of operation without recrystallization is ~250 °C. There were four publications generated from this project with two additional manuscripts in progress and six presentations were made at national and international technical conferences. The combination of the pinhole defects and the lack of high temperature stability make the theoretically identified most promising candidate amorphous alloys

  2. High-temperature Hydrogen Permeation in Nickel Alloys

    SciTech Connect

    P. Calderoni; M. Ebner; R. Pawelko

    2010-10-01

    In gas cooled Very High Temperature Reactor concepts, tritium is produced as a tertiary fission product and by activation of graphite core contaminants, such as lithium; of the helium isotope, He-3, that is naturally present in the He gas coolant; and the boron in the B4C burnable poison. Because of its high mobility at the reactor outlet temperatures, tritium poses a risk of permeating through the walls of the intermediate heat exchanger (IHX) or steam generator (SG) systems, potentially contaminating the environment and in particular the hydrogen product when the reactor heat is utilized in connection with a hydrogen generation plant. An experiment to measure tritium permeation in structural materials at temperatures up to 1000 C has been constructed at the Idaho National Laboratory Safety and Tritium Applied Research (STAR) facility within the Next Generation Nuclear Plant program. The design is based on two counter flowing helium loops to represent heat exchanger conditions and was optimized to allow control of the materials surface condition and the investigation of the effects of thermal fatigue. In the ongoing campaign three nickel alloys are being considered because of their high-temperature creep properties, alloy 617, 800H and 230. This paper introduces the general issues related to tritium in the on-going assessment of gas cooled VHTR systems fission product transport and outlines the planned research activities in this area; outlines the features and capabilities of the experimental facility being operated at INL; presents and discusses the initial results of hydrogen permeability measurements in two of the selected alloys and compares them with the available database from previous studies.

  3. Hydrogen Production:. Ceramic Materials for High Temperature Water Electrolysis

    NASA Astrophysics Data System (ADS)

    Hammou, A.

    2006-06-01

    Hydogen, H2 is regarded as the main energy vector for the future. Today, the world production of hydrogen rises to 550 billion Nm3 (44 Mt) corresponding to 1,5% of the primary energy production. Contrary to fossil fuels, H2 does not exist in a native form and its use obviously requires its fabrication and storage. The future status of H2 as a fuel for electricity production (fuel cells) and for automobile transportation makes necessary a considerable increase of its production. Some H2 manufactoring processes are briefly described in the first part of this article : (i) steam methane reforming, (ii) water decomposition by thermochemical cycles, (iii) water decomposition by photoelectrochemistry, (iv) water or organic compounds decomposition in using bacteria or alguae. The second part concerns the H2 production by water electrolysis. This manufactoring process does not exceed 1% of the total production of hydrogen. It is expected that the electrolysers working at high temperature (700-900°C) using ceramic oxides based electrolytes are the more promising. Two groups are considered: electrolysers with proton conductors or oxide ion conductors as electrolytes. Proton conductors belong to the perovskite oxides family MCe1-xLnxO3 with M = Ba, Sr and Ln = Lanthanide. For these conductors, few results on water electrolysis at high temperature are available in the litterature and will be shown here. Electrolysers using oxide ion conductors are more promising. The selected materials are those developped for SOFCs : YSZ for the electrolyte, Ni based cermets for the cathode materials and La1-xSrxMO3±δ with M = Mn, Co, Ni, Fe ... The electrochemical characteristics of the anodic and cathodic interfaces as well as the perfomances of electrolysers working at high temperature are presented.

  4. Superalloy for high-temperature hydrogen environmental applications

    NASA Technical Reports Server (NTRS)

    McKannan, Eugene C. (Inventor); McPherson, William B. (Inventor); Ahmed, Shaffiq (Inventor); Chandler, Shirley S. (Inventor)

    1991-01-01

    A nickel-based superalloy is provided which is resistant to deterioration in hydrogen at high operating temperatures and pressures, and which thus can be used in hydrogen-fueled spacecraft such as the Space Shuttle. The superalloy is characterized by a two-phase microstructure and consists of a gamma-prime precipitated phase in a gamma matrix. The gamma matrix phase is a primary solid solution and the gamma precipitated phase will be an intermetallic compound of the type A.sub.3 B, such as nickel aluminide or titanide. Both phases are coherent, ordered, and compatible, and thus will retain most of their strength at elevated temperatures. The alloy consists essentially of (by weight): Ni 50-60%, Cr 10-20%, Al 2-6%, Co 2-5%, Ti 3-8%, W 5-12%, Mo 5-10%, Nb 1-3%, wherein the ratio W/MO is approximately equal to 1, and Ti/Al ranges from about 1 to about 2.

  5. Hydrogen permeation behavior through F82H at high temperature

    SciTech Connect

    Matsuda, S.; Katayama, K.; Shimozori, M.; Fukada, S.; Ushida, H.; Nishikawa, M.

    2015-03-15

    F82H is a primary candidate of structural material and coolant pipe material in a blanket of a fusion reactor. Understanding tritium permeation behavior through F82H is important. In a normal operation of a fusion reactor, the temperature of F82H will be controlled below 550 C. degrees because it is considered that F82H can be used up to 30,000 hours at 550 C. degrees. However, it is necessary to assume the situation where F82H is heated over 550 C. degrees in a severe accident. In this study, hydrogen permeation behavior through F82H was investigated in the temperature range from 500 to 800 C. degrees. In some cases, water vapor was added in a sample gas to investigate an effect of water vapor on hydrogen permeation. The permeability of hydrogen in the temperature range from 500 to 700 C. degrees agreed well with the permeability reported by E. Serra et al. The degradation of the permeability by water vapor was not observed. After the hydrogen permeation reached in a steady state at 700 C. degrees, the F82H sample was heated to 800 C. degrees. The permeability of hydrogen through F82H sample which was once heated up to 800 C. degrees was lower than that of the original one. (authors)

  6. GFOC Project results: High Temperature / High Pressure, Hydrogen Tolerant Optical Fiber

    SciTech Connect

    E. Burov; A. Pastouret; E. Aldea; B. Overton; F. Gooijer; A. Bergonzo

    2012-02-12

    Tests results are given for exposure of multimode optical fiber to high temperatures (300 deg. C) and high partial pressure (15 bar) hydrogen. These results demonstrate that fluorine down doped optical fibers are much more hydrogen tolerant than traditional germanium doped multimode optical fibers. Also demonstrated is the similar hydrogen tolerance of carbon coated and non-carbon coated fibers. Model for reversible H2 impact in fiber versus T{sup o}C and H2 pressure is given. These results have significant impact for the longevity of use for distributed temperature sensing applications in harsh environments such as geothermal wells.

  7. HIGH-TEMPERATURE ELECTROLYSIS FOR HYDROGEN PRODUCTION FROM NUCLEAR ENERGY

    SciTech Connect

    James E. O'Brien; Carl M. Stoots; J. Stephen Herring; Joseph J. Hartvigsen

    2005-10-01

    An experimental study is under way to assess the performance of solid-oxide cells operating in the steam electrolysis mode for hydrogen production over a temperature range of 800 to 900ºC. Results presented in this paper were obtained from a ten-cell planar electrolysis stack, with an active area of 64 cm2 per cell. The electrolysis cells are electrolyte-supported, with scandia-stabilized zirconia electrolytes (~140 µm thick), nickel-cermet steam/hydrogen electrodes, and manganite air-side electrodes. The metallic interconnect plates are fabricated from ferritic stainless steel. The experiments were performed over a range of steam inlet mole fractions (0.1 - 0.6), gas flow rates (1000 - 4000 sccm), and current densities (0 to 0.38 A/cm2). Steam consumption rates associated with electrolysis were measured directly using inlet and outlet dewpoint instrumentation. Cell operating potentials and cell current were varied using a programmable power supply. Hydrogen production rates up to 90 Normal liters per hour were demonstrated. Values of area-specific resistance and stack internal temperatures are presented as a function of current density. Stack performance is shown to be dependent on inlet steam flow rate.

  8. Silicon Carbide-Based Hydrogen Gas Sensors for High-Temperature Applications

    PubMed Central

    Kim, Seongjeen; Choi, Jehoon; Jung, Minsoo; Joo, Sungjae; Kim, Sangchoel

    2013-01-01

    We investigated SiC-based hydrogen gas sensors with metal-insulator-semiconductor (MIS) structure for high temperature process monitoring and leak detection applications in fields such as the automotive, chemical and petroleum industries. In this work, a thin tantalum oxide (Ta2O5) layer was exploited with the purpose of sensitivity improvement, because tantalum oxide has good stability at high temperature with high permeability for hydrogen gas. Silicon carbide (SiC) was used as a substrate for high-temperature applications. We fabricated Pd/Ta2O5/SiC-based hydrogen gas sensors, and the dependence of their I-V characteristics and capacitance response properties on hydrogen concentrations were analyzed in the temperature range from room temperature to 500 °C. According to the results, our sensor shows promising performance for hydrogen gas detection at high temperatures. PMID:24113685

  9. Silicon carbide-based hydrogen gas sensors for high-temperature applications.

    PubMed

    Kim, Seongjeen; Choi, Jehoon; Jung, Minsoo; Joo, Sungjae; Kim, Sangchoel

    2013-01-01

    We investigated SiC-based hydrogen gas sensors with metal-insulator-semiconductor (MIS) structure for high temperature process monitoring and leak detection applications in fields such as the automotive, chemical and petroleum industries. In this work, a thin tantalum oxide (Ta2O5) layer was exploited with the purpose of sensitivity improvement, because tantalum oxide has good stability at high temperature with high permeability for hydrogen gas. Silicon carbide (SiC) was used as a substrate for high-temperature applications. We fabricated Pd/Ta2O5/SiC-based hydrogen gas sensors, and the dependence of their I-V characteristics and capacitance response properties on hydrogen concentrations were analyzed in the temperature range from room temperature to 500 °C. According to the results, our sensor shows promising performance for hydrogen gas detection at high temperatures. PMID:24113685

  10. LARGE-SCALE HYDROGEN PRODUCTION FROM NUCLEAR ENERGY USING HIGH TEMPERATURE ELECTROLYSIS

    SciTech Connect

    James E. O'Brien

    2010-08-01

    Hydrogen can be produced from water splitting with relatively high efficiency using high-temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high-temperature process heat. When coupled to an advanced high temperature nuclear reactor, the overall thermal-to-hydrogen efficiency for high-temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. Demand for hydrogen is increasing rapidly for refining of increasingly low-grade petroleum resources, such as the Athabasca oil sands and for ammonia-based fertilizer production. Large quantities of hydrogen are also required for carbon-efficient conversion of biomass to liquid fuels. With supplemental nuclear hydrogen, almost all of the carbon in the biomass can be converted to liquid fuels in a nearly carbon-neutral fashion. Ultimately, hydrogen may be employed as a direct transportation fuel in a “hydrogen economy.” The large quantity of hydrogen that would be required for this concept should be produced without consuming fossil fuels or emitting greenhouse gases. An overview of the high-temperature electrolysis technology will be presented, including basic theory, modeling, and experimental activities. Modeling activities include both computational fluid dynamics and large-scale systems analysis. We have also demonstrated high-temperature electrolysis in our laboratory at the 15 kW scale, achieving a hydrogen production rate in excess of 5500 L/hr.

  11. High temperature hydrogen sulfide removal with tin oxide

    SciTech Connect

    Karpuk, M.E.; Copeland, R.J.; Feinberg, D.; Wickham, D.; Windecker, B.; Yu, J.

    1993-09-01

    The system is based on the absorption of hydrogen sulfide (H{sub 2}S) by stannic (tin) oxide. Two sorbents are required, the first sorbent is tin oxide and the second sorbent is a zinc oxide based material (i.e., zinc ferrite or zinc titanate) which is regenerated by air producing SO{sub 2}. TDA`s process carries out a modified Claus reaction to reduce the SO{sub 2} from the second sorbent generation to elemental sulfur. In this case the sulfided stannic oxide forms stannous sulfide (SnS) which reduces the SO{sub 2}. The absorption by SnO{sub 2} could remove over 90% of the H{sub 2}S from typical coal gas streams, but we use zinc ferrite (or zinc titanate), (a) to reduce H{sub 2}S to less than 20 ppM and (b) as a source of SO{sub 2} in regeneration. Due to stoichiometry of regeneration we want to remove half of the H{sub 2}S by SnO{sub 2} and the remainder by the second sorbent. The reactions with stannic oxide minimize the heat released during H{sub 2}S removal and regeneration. The absorption by SnO{sub 2} is slightly endothermic and cools the gas stream by less that 5{degrees}F (2.8{degrees}C) during absorption. Regeneration with SO{sub 2} is exothermic but releases only 11% of the heat that is liberated in regenerating the ZnO. For a nominal 6.5:1 steam to air the regeneration of ZnO increases the temperature by {approx_equal}400{degrees}F. The regeneration of SnO{sub 2} increases the temperature by less than 50{degrees}F (28{degrees}C) in the same gas flow.

  12. Hydrogen absorption in solid aluminum during high-temperature steam oxidation

    NASA Technical Reports Server (NTRS)

    Andreev, L. A.; Gelman, B. G.; Zhukhovitskiy, A. A.

    1979-01-01

    Hydrogen is emitted by aluminum heated in a vacuum after high-temperature steam treatment. Wire samples are tested for this effect, showing dependence on surface area. Two different mechanisms of absorption are inferred, and reactions deduced.

  13. High performance nickel-palladium nanocatalyst for hydrogen generation from alkaline hydrous hydrazine at room temperature

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Debaleena; Mandal, Kaustab; Dasgupta, Subrata

    2015-08-01

    Room temperature synthesized highly active bimetallic Ni60Pd40 nanocatalyst with large surface area (150 m2g-1) exerts 100% selectivity towards hydrogen generation (3 equivalents of gas in 60 min) from hydrous hydrazine under alkaline and ambient reaction conditions. This low noble metal content catalyst offers a new prospect for on-board hydrogen production system.

  14. High-temperature effect of hydrogen on sintered alpha-silicon carbide

    NASA Technical Reports Server (NTRS)

    Hallum, G. W.; Herbell, T. P.

    1986-01-01

    Sintered alpha-silicon carbide was exposed to pure, dry hydrogen at high temperatures for times up to 500 hr. Weight loss and corrosion were seen after 50 hr at temperatures as low as 1000 C. Corrosion of SiC by hydrogen produced grain boundary deterioration at 1100 C and a mixture of grain and grain boundary deterioration at 1300 C. Statistically significant strength reductions were seen in samples exposed to hydrogen for times greater than 50 hr and temperatures above 1100 C. Critical fracture origins were identified by fractography as either general grain boundary corrision at 1100 C or as corrosion pits at 1300 C. A maximum strength decrease of approximately 33 percent was seen at 1100 and 1300 C after 500 hr exposure to hydrogen. A computer assisted thermodynamic program was also used to predict possible reaction species of SiC and hydrogen.

  15. Economic Analysis of a Nuclear Reactor Powered High-Temperature Electrolysis Hydrogen Production Plant

    SciTech Connect

    E. A. Harvego; M. G. McKellar; M. S. Sohal; J. E. O'Brien; J. S. Herring

    2008-08-01

    A reference design for a commercial-scale high-temperature electrolysis (HTE) plant for hydrogen production was developed to provide a basis for comparing the HTE concept with other hydrogen production concepts. The reference plant design is driven by a high-temperature helium-cooled nuclear reactor coupled to a direct Brayton power cycle. The reference design reactor power is 600 MWt, with a primary system pressure of 7.0 MPa, and reactor inlet and outlet fluid temperatures of 540°C and 900°C, respectively. The electrolysis unit used to produce hydrogen includes 4,009,177 cells with a per-cell active area of 225 cm2. The optimized design for the reference hydrogen production plant operates at a system pressure of 5.0 MPa, and utilizes an air-sweep system to remove the excess oxygen that is evolved on the anode (oxygen) side of the electrolyzer. The inlet air for the air-sweep system is compressed to the system operating pressure of 5.0 MPa in a four-stage compressor with intercooling. The alternating-current, AC, to direct-current, DC, conversion efficiency is 96%. The overall system thermal-to-hydrogen production efficiency (based on the lower heating value of the produced hydrogen) is 47.12% at a hydrogen production rate of 2.356 kg/s. An economic analysis of this plant was performed using the standardized H2A Analysis Methodology developed by the Department of Energy (DOE) Hydrogen Program, and using realistic financial and cost estimating assumptions. The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a competitive cost. A cost of $3.23/kg of hydrogen was calculated assuming an internal rate of return of 10%.

  16. Highly mobile and reactive state of hydrogen in metal oxide semiconductors at room temperature

    NASA Astrophysics Data System (ADS)

    Chen, Wan Ping; He, Ke Feng; Wang, Yu; Chan, Helen Lai Wah; Yan, Zijie

    2013-11-01

    Hydrogen in metal oxides usually strongly associates with a neighboring oxygen ion through an O-H bond and thus displays a high stability. Here we report a novel state of hydrogen with unusually high mobility and reactivity in metal oxides at room temperature. We show that freshly doped hydrogen in Nb2O5 and WO3 polycrystals via electrochemical hydrogenation can reduce Cu2+ ions into Cu0 if the polycrystals are immersed in a CuSO4 solution, while this would not happen if the hydrogenated polycrystals have been placed in air for several hours before the immersion. Time-dependent studies of electrochemically hydrogenated rutile single crystals reveal two distinct states of hydrogen: one as protons covalently bonded to oxygen ions, while the other one is highly unstable with a lifetime of just a few hours. Observation of this mobile and reactive state of hydrogen will provide new insight into numerous moderate and low temperature interactions between metal oxides and hydrogen.

  17. Phase transformation of oxide film in zirconium alloy in high temperature hydrogenated water

    SciTech Connect

    Kim, Taeho; Kim, Jongjin; Choi, Kyoung Joon; Yoo, Seung Chang; Kim, Seung Hyun; Kim, Ji Hyun

    2015-07-23

    The effect of the variation of the dissolved hydrogen concentration on the oxide phase transformation under high-temperature hydrogenated water conditions was investigated using in situ Raman spectroscopy. The Raman spectrum in 50 cm(3)/kg of dissolved hydrogen concentration indicated the formation of monoclinic and tetragonal zirconium oxide at the water-substrate interface. As the dissolved hydrogen concentration decreased to 30 cm(3)/kg, the Raman peaks corresponding to the zirconium oxide phase changed, indicating an oxide phase transformation. And, the results of SEM and TEM analyses were compared with those of in situ analyses obtained for the oxide structure formed on the zirconium alloy.

  18. Hydrogen production by high-temperature steam gasification of biomass and coal

    SciTech Connect

    Kriengsak, S.N.; Buczynski, R.; Gmurczyk, J.; Gupta, A.K.

    2009-04-15

    High-temperature steam gasification of paper, yellow pine woodchips, and Pittsburgh bituminous coal was investigated in a batch-type flow reactor at temperatures in the range of 700 to 1,200{sup o}C at two different ratios of steam to feedstock molar ratios. Hydrogen yield of 54.7% for paper, 60.2% for woodchips, and 57.8% for coal was achieved on a dry basis, with a steam flow rate of 6.3 g/min at steam temperature of 1,200{sup o}C. Yield of both the hydrogen and carbon monoxide increased while carbon dioxide and methane decreased with the increase in gasification temperature. A 10-fold reduction in tar residue was obtained at high-temperature steam gasification, compared to low temperatures. Steam and gasification temperature affects the composition of the syngas produced. Higher steam-to-feedstock molar ratio had negligible effect on the amount of hydrogen produced in the syngas in the fixed-batch type of reactor. Gasification temperature can be used to control the amounts of hydrogen or methane produced from the gasification process. This also provides mean to control the ratio of hydrogen to CO in the syngas, which can then be processed to produce liquid hydrocarbon fuel since the liquid fuel production requires an optimum ratio between hydrogen and CO. The syngas produced can be further processed to produce pure hydrogen. Biomass fuels are good source of renewable fuels to produce hydrogen or liquid fuels using controlled steam gasification.

  19. A Process Model for the Production of Hydrogen Using High Temperature Electrolysis

    SciTech Connect

    M. G. Mc Kellar; E. A. Harvego; M. Richards; A. Shenoy

    2006-07-01

    High temperature electrolysis (HTE) involves the splitting of stream into hydrogen and oxygen at high temperatures. The primary advantage of HTE over conventional low temperature electrolysis is that considerably higher hydrogen production efficiencies can be achieved. Performing the electrolysis process at high temperatures results in more favorable thermodynamics for electrolysis, more efficient production of electricity, and allows direct use of process heat to generate steam. This paper presents the results of process analyses performed to evaluate the hydrogen production efficiencies of an HTE plant coupled to a 600 MWt Modular Helium Reactor (MHR) that supplies both the electricity and process heat needed to drive the process. The MHR operates with a coolant outlet temperature of 950 C. Approximately 87% of the high-temperature heat is used to generate electricity at high efficiency using a direct, Brayton-cycle power conversion system. The remaining high-temperature heat is used to generate a superheated steam / hydrogen mixture that is supplied to the electrolyzers. The analyses were performed using the HYSYS process modeling software. The model used to perform the analyses consisted of three loops; a primary high temperature helium loop, a secondary helium loop and the HTE process loop. The detailed model included realistic representations of all major components in the system, including pumps, compressors, heat exchange equipment, and the electrolysis stack. The design of the hydrogen production process loop also included a steam-sweep gas system to remove oxygen from the electrolysis stack so that it can be recovered and used for other applications. Results of the process analyses showed that hydrogen production efficiencies in the range of 45% to 50% are achievable with this system.

  20. CHALLENGES IN GENERATING HYDROGEN BY HIGH TEMPERATURE ELECTROLYSIS USING SOLID OXIDE CELLS

    SciTech Connect

    M. S. Sohal; J. E. O'Brien; C. M. Stoots; M. G. McKellar; J. S. Herring; E. A. Harvego

    2008-03-01

    Idaho National Laboratory’s (INL) high temperature electrolysis research to generate hydrogen using solid oxide electrolysis cells is presented in this paper. The research results reported here have been obtained in a laboratory-scale apparatus. These results and common scale-up issues also indicate that for the technology to be successful in a large industrial setting, several technical, economical, and manufacturing issues have to be resolved. Some of the issues related to solid oxide cells are stack design and performance optimization, identification and evaluation of cell performance degradation parameters and processes, integrity and reliability of the solid oxide electrolysis (SOEC) stacks, life-time prediction and extension of the SOEC stack, and cost reduction and economic manufacturing of the SOEC stacks. Besides the solid oxide cells, balance of the hydrogen generating plant also needs significant development. These issues are process and ohmic heat source needed for maintaining the reaction temperature (~830°C), high temperature heat exchangers and recuperators, equal distribution of the reactants into each cell, system analysis of hydrogen and associated energy generating plant, and cost optimization. An economic analysis of this plant was performed using the standardized H2A Analysis Methodology developed by the Department of Energy (DOE) Hydrogen Program, and using realistic financial and cost estimating assumptions. The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a cost of $3.23/kg of hydrogen assuming an internal rate of return of 10%. These issues need interdisciplinary research effort of federal laboratories, solid oxide cell manufacturers, hydrogen consumers, and other such stakeholders. This paper discusses research and development accomplished by INL on such issues and highlights associated challenges that need to

  1. Analysis of Improved Reference Design for a Nuclear-Driven High Temperature Electrolysis Hydrogen Production Plant

    SciTech Connect

    Edwin A. Harvego; James E. O'Brien; Michael G. McKellar

    2010-06-01

    The use of High Temperature Electrolysis (HTE) for the efficient production of hydrogen without the greenhouse gas emissions associated with conventional fossil-fuel hydrogen production techniques has been under investigation at the Idaho National Engineering Laboratory (INL) for the last several years. The activities at the INL have included the development, testing and analysis of large numbers of solid oxide electrolysis cells, and the analyses of potential plant designs for large scale production of hydrogen using an advanced Very-High Temperature Reactor (VHTR) to provide the process heat and electricity to drive the electrolysis process. The results of these system analyses, using the UniSim process analysis software, have shown that the HTE process, when coupled to a VHTR capable of operating at reactor outlet temperatures of 800 °C to 950 °C, has the potential to produce the large quantities of hydrogen needed to meet future energy and transportation needs with hydrogen production efficiencies in excess of 50%. In addition, economic analyses performed on the INL reference plant design, optimized to maximize the hydrogen production rate for a 600 MWt VHTR, have shown that a large nuclear-driven HTE hydrogen production plant can to be economically competitive with conventional hydrogen production processes, particularly when the penalties associated with greenhouse gas emissions are considered. The results of this research led to the selection in 2009 of HTE as the preferred concept in the U.S. Department of Energy (DOE) hydrogen technology down-selection process. However, the down-selection process, along with continued technical assessments at the INL, has resulted in a number of proposed modifications and refinements to improve the original INL reference HTE design. These modifications include changes in plant configuration, operating conditions and individual component designs. This paper describes the resulting new INL reference design and presents

  2. Phase transitions and hydrogen bonding in deuterated calcium hydroxide: High-pressure and high-temperature neutron diffraction measurements

    SciTech Connect

    Iizuka, Riko; Komatsu, Kazuki; Kagi, Hiroyuki; Nagai, Takaya; Sano-Furukawa, Asami; Hattori, Takanori; Gotou, Hirotada; Yagi, Takehiko

    2014-10-15

    In situ neutron diffraction measurements combined with the pulsed neutron source at the Japan Proton Accelerator Research Complex (J-PARC) were conducted on high-pressure polymorphs of deuterated portlandite (Ca(OD){sub 2}) using a Paris–Edinburgh cell and a multi-anvil press. The atomic positions including hydrogen for the unquenchable high-pressure phase at room temperature (phase II′) were first clarified. The bent hydrogen bonds under high pressure were consistent with results from Raman spectroscopy. The structure of the high-pressure and high-temperature phase (Phase II) was concordant with that observed previously by another group for a recovered sample. The observations elucidate the phase transition mechanism among the polymorphs, which involves the sliding of CaO polyhedral layers, position modulations of Ca atoms, and recombination of Ca–O bonds accompanied by the reorientation of hydrogen to form more stable hydrogen bonds. - Graphical abstract: Crystal structures of high-pressure polymorphs of Ca(OD){sub 2}, (a) at room temperature (phase II′) and (b) at high temperature (phase II), were obtained from in situ neutron diffraction measurements. - Highlights: • We measured in situ neutron diffraction of high-pressure polymorphs of Ca(OD){sub 2}. • Hydrogen positions of the high-pressure phase are first determined. • The obtained hydrogen bonds reasonably explain Raman peaks of OH stretching modes. • A phase transition mechanism among the polymorphs is proposed.

  3. 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. PMID:23802976

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

    NASA Astrophysics Data System (ADS)

    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.

    2013-06-01

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

  5. High temperature hydrogen sulfide removal with tin oxide

    SciTech Connect

    Copeland, R.J.; Feinberg, D.; Wickham, D.; Windecker, B.; Yu, J.

    1993-06-01

    This Phase II SBIR contract is developing a sorbent and process which removes H{sub 2}S from hot gasified coal and generates sulfur during regeneration of the sorbent. The process can be used with any type of reactor (e.g., fixed or moving bed) and any gasifier (e.g., KRW or Texaco) and shows lower costs that competing H{sub 2}S removal processes. TDA Research`s (TDA) process uses a regenerable stannic oxide-based (SnO{sub 2}) sorbent as the first sorbent and zinc ferrite (or zinc titanate) as a second sorbent to remove H{sub 2}S to very low concentrations. The process converts the sulfides from both sorbents to elemental sulfur, a commercial product which is easy to store and transport. The object of this phase is to develop chemically active, high sulfur loadings, and durable stannic oxide sorbents and to demonstrate the process at the bench scale.

  6. Studies of the use of high-temperature nuclear heat from an HTGR for hydrogen production

    NASA Technical Reports Server (NTRS)

    Peterman, D. D.; Fontaine, R. W.; Quade, R. N.; Halvers, L. J.; Jahromi, A. M.

    1975-01-01

    The results of a study which surveyed various methods of hydrogen production using nuclear and fossil energy are presented. A description of these methods is provided, and efficiencies are calculated for each case. The process designs of systems that utilize the heat from a general atomic high temperature gas cooled reactor with a steam methane reformer and feed the reformer with substitute natural gas manufactured from coal, using reforming temperatures, are presented. The capital costs for these systems and the resultant hydrogen production price for these cases are discussed along with a research and development program.

  7. System Evaluation and Economic Analysis of a HTGR Powered High-Temperature Electrolysis Hydrogen Production Plant

    SciTech Connect

    Michael G. McKellar; Edwin A. Harvego; Anastasia A. Gandrik

    2010-10-01

    A design for a commercial-scale high-temperature electrolysis (HTE) plant for hydrogen production has been developed. The HTE plant is powered by a high-temperature gas-cooled reactor (HTGR) whose configuration and operating conditions are based on the latest design parameters planned for the Next Generation Nuclear Plant (NGNP). The current HTGR reference design specifies a reactor power of 600 MWt, with a primary system pressure of 7.0 MPa, and reactor inlet and outlet fluid temperatures of 322°C and 750°C, respectively. The power conversion unit will be a Rankine steam cycle with a power conversion efficiency of 40%. The reference hydrogen production plant operates at a system pressure of 5.0 MPa, and utilizes a steam-sweep system to remove the excess oxygen that is evolved on the anode (oxygen) side of the electrolyzer. The overall system thermal-to-hydrogen production efficiency (based on the higher heating value of the produced hydrogen) is 40.4% at a hydrogen production rate of 1.75 kg/s and an oxygen production rate of 13.8 kg/s. An economic analysis of this plant was performed with realistic financial and cost estimating assumptions. The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a cost of $3.67/kg of hydrogen assuming an internal rate of return, IRR, of 12% and a debt to equity ratio of 80%/20%. A second analysis shows that if the power cycle efficiency increases to 44.4%, the hydrogen production efficiency increases to 42.8% and the hydrogen and oxygen production rates are 1.85 kg/s and 14.6 kg/s respectively. At the higher power cycle efficiency and an IRR of 12% the cost of hydrogen production is $3.50/kg.

  8. Design of an Integrated Laboratory Scale Test for Hydrogen Production via High Temperature Electrolysis

    SciTech Connect

    G.K. Housley; K.G. Condie; J.E. O'Brien; C. M. Stoots

    2007-06-01

    The Idaho National Laboratory (INL) is researching the feasibility of high-temperature steam electrolysis for high-efficiency carbon-free hydrogen production using nuclear energy. Typical temperatures for high-temperature electrolysis (HTE) are between 800º-900ºC, consistent with anticipated coolant outlet temperatures of advanced high-temperature nuclear reactors. An Integrated Laboratory Scale (ILS) test is underway to study issues such as thermal management, multiple-stack electrical configuration, pre-heating of process gases, and heat recuperation that will be crucial in any large-scale implementation of HTE. The current ILS design includes three electrolysis modules in a single hot zone. Of special design significance is preheating of the inlet streams by superheaters to 830°C before entering the hot zone. The ILS system is assembled on a 10’ x 16’ skid that includes electronics, power supplies, air compressor, pumps, superheaters, , hot zone, condensers, and dew-point sensor vessels. The ILS support system consists of three independent, parallel supplies of electrical power, sweep gas streams, and feedstock gas mixtures of hydrogen and steam to the electrolysis modules. Each electrolysis module has its own support and instrumentation system, allowing for independent testing under different operating conditions. The hot zone is an insulated enclosure utilizing electrical heating panels to maintain operating conditions. The target hydrogen production rate for the ILS is 5000 Nl/hr.

  9. Fractography of the high temperature hydrogen attack of a medium carbon steel

    NASA Technical Reports Server (NTRS)

    Melson, H. G.; Moorhead, R. D.

    1975-01-01

    Microscopic fracture processes were studied which are associated with hydrogen attack of a medium carbon steel in a well-controlled, high-temperature, high-purity hydrogen environment. Exposure to a hydrogen pressure and temperature of 3.5 MN/m2 and 575 C was found to degrade room temperature tensile properties with increasing exposure time. After 408 hr, yield and ultimate strengths were reduced by more than 40 percent and elongation was reduced to less than 2 percent. Initial fissure formation was found to be associated with manganese rich particles, most probably manganese oxide, aligned in the microstructure during the rolling operation. Fissure growth was found to be associated with a reduction in carbide content of the microstructure and was inhibited by the depletion of carbon. The interior surfaces of sectioned fissures or bubbles exhibit both primary and secondary cracking by intergranular separation. The grain surfaces were rough and rounded, suggesting a diffusion-associated separation process. Specimens that failed at room temperature after exposure to hydrogen were found to exhibit mixed mode fracture having varying amounts of intergranular separation, dimple formation, and cleavage, depending on exposure time.

  10. High temperature catalytic hydrogenation of acetone over Raney Ni for chemical heat pump

    NASA Astrophysics Data System (ADS)

    Duan, Yanjun; Xu, Min; Huai, Xiulan

    2014-02-01

    Exothermic hydrogenation reaction of acetone is an important part of an IAH-CHP, and the performance of IAH-CHP is affected directly by this reaction. This paper studies the influence of space velocity, temperature, hydrogen flow rate and pressure on conversion and selectivity experimentally. The byproducts are analyzed and classified into three types: hydrogenation product, cracking products and condensation products. Both the conversion and selectivity of this reaction have the same trend with the change of space velocity, temperature and hydrogen flow rate, and has the opposite trend with the change of pressure. As the space velocity increases, the conversion curve is a gradual decline parabola but the selectivity curve is close to a straight line. Hydrogen flow rate has a more obvious influence on conversion than temperature, whereas on selectivity the situation is opposite. High pressure increases the conversion of acetone to all products, but the increment of byproducts is more than that of isopropanol, so the selectivity decreases as pressure increases.

  11. Hydrogen atom recombination on tungsten at high temperature: Experiment and Molecular Dynamics Simulation

    NASA Astrophysics Data System (ADS)

    Rutigliano, M.; Santoro, D.; Balat-Pichelin, M.

    2014-10-01

    Atom recombination at wall is a phenomenon involved in many plasma experiments and also in present tokamaks and future fusion plasma reactors like ITER. This exothermic surface reaction is catalyzed by the material and depends on its composition and temperature. In the MESOX experimental set-up, several methods were developed for the measurement of the recombination parameters. In this paper, a method developed for the experimental evaluation of the recombination coefficient of atomic hydrogen γH on tungsten at high temperature is presented using two series of atomic lines (Hα and He or Hβ and H2) and the results obtained for surface temperature up to 1350 K are given. A Molecular Dynamics Simulation has been done for the recombination of hydrogen atoms on tungsten in conditions close to the experimental ones using a semi-classical collisional method. Modeling results are compared to the experimental data for two surface temperature values and a fairly good agreement was obtained.

  12. The high-temperature sodium coolant technology in nuclear power installations for hydrogen power engineering

    NASA Astrophysics Data System (ADS)

    Kozlov, F. A.; Sorokin, A. P.; Alekseev, V. V.; Konovalov, M. A.

    2014-05-01

    In the case of using high-temperature sodium-cooled nuclear power installations for obtaining hydrogen and for other innovative applications (gasification and fluidization of coal, deep petroleum refining, conversion of biomass into liquid fuel, in the chemical industry, metallurgy, food industry, etc.), the sources of hydrogen that enters from the reactor plant tertiary coolant circuit into its secondary coolant circuit have intensity two or three orders of magnitude higher than that of hydrogen sources at a nuclear power plant (NPP) equipped with a BN-600 reactor. Fundamentally new process solutions are proposed for such conditions. The main prerequisite for implementing them is that the hydrogen concentration in sodium coolant is a factor of 100-1000 higher than it is in modern NPPs taken in combination with removal of hydrogen from sodium by subjecting it to vacuum through membranes made of vanadium or niobium. Numerical investigations carried out using a diffusion model showed that, by varying such parameters as fuel rod cladding material, its thickness, and time of operation in developing the fuel rods for high-temperature nuclear power installations (HT NPIs) it is possible to exclude ingress of cesium into sodium through the sealed fuel rod cladding. However, if the fuel rod cladding loses its tightness, operation of the HT NPI with cesium in the sodium will be unavoidable. Under such conditions, measures must be taken for deeply purifying sodium from cesium in order to minimize the diffusion of cesium into the structural materials.

  13. Improvement of Electron Field Emission in Patterned Carbon Nanotubes by High Temperature Hydrogen Plasma Treatment

    PubMed Central

    Wang, Sigen; Sellin, Paul. J.; Lian, Jun; Özsan, Ersin; Chang, Sha

    2009-01-01

    In this paper, we report a significant improvement of electron field emission property in patterned carbon nanotubes films by using a high temperature (650 °C) hydrogen plasma treatment. This treatment was found to greatly increase the emission current, emission uniformity and stability. The mechanism study showed that these enhanced properties are attributed to the lowering of the potential barrier and the creation of geometrical features through the removal of amorphous carbon, catalyst particles and the saturation of dangling bonds after such a hydrogen plasma treatment. PMID:19946566

  14. High-rate/high-temperature capability of a single-layer zicar-separator nickel-hydrogen cell

    NASA Technical Reports Server (NTRS)

    Wheeler, James R.

    1995-01-01

    A 50 Ampere-hour nickel-hydrogen cell with a single-layer Zircar separator stack design was fully charged and then discharged at a 2C current rate to an end voltage of 1 volt. This extreme test resulted in high temperatures which were recorded at three locations on the cell, i.e., the cell wall, the boss (barrel of the compression seal), and a terminal. The results provide new information about the high-temperature and high-discharge-rate capabilities of nickel-hydrogen cells. This information also adds to the growing data base for single-layer zirconium-oxide-cloth (Zircar) separator cell designs.

  15. Materials for high-temperature hydrogen fluorine environments. Final report, June 1976-December 1978

    SciTech Connect

    Holcombe, C.E. Jr.; Kovach, L.

    1981-03-01

    A determination has been made of the stability of 35 materials under high-temperature, fluorine rich, hydrogen fluoride torch testing. Refractory materials tested included 4 borides, 3 carbides, 3 nitrides, 12 oxides, 1 oxynitride, 1 sulfide, 10 metals, and carbon (10 types). Three materials distinctly performed better than nickel: lanthanum hexaboride, calcium hexaboride, and lanthanum silicon oxynitride. Of these, lanthanum hexaboride is the best candidate tested since it has an estimated upper use temperature > 1726 K, which is above the melting point and more than 300 K above the upper use temperature of nickel.

  16. Initial hydrogen detonation data from the High-Temperature Combustion Facility

    SciTech Connect

    Ginsberg, T.; Ciccarelli, G.; Boccio, J.

    1994-12-31

    The Brookhaven National Laboratory High-Temperature Combustion Facility (HTCF) is described and data from initial hydrogen detonation experiments are presented. Initial phase of the inherent detonability experimental program is described. Test gases thus far tested are hydrogen-air mixtures at one atmosphere initial pressure and temperatures 300K-650K. Detonation pressure, wave speed, and detonation cell size were measured. Data were consistent with earlier SSDA (small-scale development apparatus) test results. HTCF results confirm the conclusion from the SSDA program that the gas temperature decreases the cell size and, therefore, increases the sensitivity of mixtures to detonation. Data from the larger HTCF test vessel, however, also demonstrates that the effect of increased scale is to extend the range of detonable mixtures to lower concentration.

  17. Fractography of the high temperature hydrogen attack of a medium carbon steel

    NASA Technical Reports Server (NTRS)

    Nelson, H. G.; Moorhead, R. D.

    1976-01-01

    Results are reported for an experimental study of the microscopic fracture processes associated with hydrogen attack of a commercially produced plain carbon steel in a well-controlled high-temperature hydrogen environment of high purity. In the experiments, sheet samples were exposed to laboratory-grade hydrogen at a pressure of 3.5 MN/sq m and a temperature of 575 C. The fractography of gas-filled fissures and failed tension specimens is analyzed in an effort to identify any predominant microstructural defect associated with fissure formation, the prevalent modes of fracture, and the contribution of gas-filled fissures to the overall failure process. It is found that the tensile properties of the examined steel were significantly degraded after as few as 136 hr of exposure to a high-purity hydrogen atmosphere at 575 C; that the yield strength, ultimate strength, and elongation at fracture were all reduced progressively with increasing exposure time; and that the yield and ultimate strengths were reduced more than 40% after 408 hr while elongation was reduced to less than 2%.

  18. Materials for high-temperature and high-pressure hydrogen peroxide bleaching equipment

    SciTech Connect

    Clarke, S.J.; Clarke, P.H.

    1999-07-01

    To determine the suitability of grade 705 zirconium (UNS R60705) as a candidate material of construction for high-temperature and pressure hydrogen peroxide (P{sub HT}) pulp-bleaching reactors, a series of electrochemical experiments were carried out in simulated P{sub HT} environments. Because the P{sub HT} process may be incorporated into a closed cycle mill or a mill that also uses chlorine-based chemicals to bleach pulp, the effect of chloride ion concentration on the corrosion of zirconium in P{sub HT} environments was studied. It was found that at the potential measured in P{sub HT} environments, zirconium was passive ({minus}100 mV vs. saturated calomel electrode [SCE]). Breakdown potentials of {approximately}500 mV{sub SCE} were measured in chloride-containing solutions. However, when the chloride ion concentration was increased >50 ppm, the repassivation potential of the zirconium was reduced significantly. Based on these results, grade 705 zirconium was determined to be suitable for a wide range of P{sub HT} process conditions.

  19. Integrated High Temperature Coal-to-Hydrogen System with CO2 Separation

    SciTech Connect

    James A. Ruud; Anthony Ku; Vidya Ramaswamy; Wei Wei; Patrick Willson

    2007-05-31

    A significant barrier to the commercialization of coal-to-hydrogen technologies is high capital cost. The purity requirements for H{sub 2} fuels are generally met by using a series of unit clean-up operations for residual CO removal, sulfur removal, CO{sub 2} removal and final gas polishing to achieve pure H{sub 2}. A substantial reduction in cost can be attained by reducing the number of process operations for H{sub 2} cleanup, and process efficiency can be increased by conducting syngas cleanup at higher temperatures. The objective of this program was to develop the scientific basis for a single high-temperature syngas-cleanup module to produce a pure stream of H{sub 2} from a coal-based system. The approach was to evaluate the feasibility of a 'one box' process that combines a shift reactor with a high-temperature CO{sub 2}-selective membrane to convert CO to CO{sub 2}, remove sulfur compounds, and remove CO{sub 2} in a simple, compact, fully integrated system. A system-level design was produced for a shift reactor that incorporates a high-temperature membrane. The membrane performance targets were determined. System level benefits were evaluated for a coal-to-hydrogen system that would incorporate membranes with properties that would meet the performance targets. The scientific basis for high temperature CO{sub 2}-selective membranes was evaluated by developing and validating a model for high temperature surface flow membranes. Synthesis approaches were pursued for producing membranes that integrated control of pore size with materials adsorption properties. Room temperature reverse-selectivity for CO{sub 2} was observed and performance at higher temperatures was evaluated. Implications for future membrane development are discussed.

  20. Large-scale preparation of graphene by high temperature insertion of hydrogen into graphite.

    PubMed

    Kamali, Ali Reza; Fray, Derek J

    2015-07-14

    Experimental evidence for high temperature diffusion of hydrogen into the interlayer space of graphite is provided. This process is discussed as a possible method for the rapid production of high-quality, inexpensive graphene in large quantities, which could lead to the widespread application of graphene. It was found that hydrogen cations, dissolved in molten LiCl, can be discharged on cathodically polarized graphite rods, which then intercalate into the graphite structure, leading to the peeling of graphite to produce graphene. The graphene nanosheets produced displayed a single-crystalline structure with a lateral size of several hundred nanometers and a high degree of crystallinity and thermal stability. The method introduced could be scaled up to produce industrial quantities of high-quality graphene. PMID:26053881

  1. High Temperature Electrolysis for Hydrogen Production from Nuclear Energy – TechnologySummary

    SciTech Connect

    J. E. O'Brien; C. M. Stoots; J. S. Herring; M. G. McKellar; E. A. Harvego; M. S. Sohal; K. G. Condie

    2010-02-01

    The Department of Energy, Office of Nuclear Energy, has requested that a Hydrogen Technology Down-Selection be performed to identify the hydrogen production technology that has the best potential for timely commercial demonstration and for ultimate deployment with the Next Generation Nuclear Plant (NGNP). An Independent Review Team has been assembled to execute the down-selection. This report has been prepared to provide the members of the Independent Review Team with detailed background information on the High Temperature Electrolysis (HTE) process, hardware, and state of the art. The Idaho National Laboratory has been serving as the lead lab for HTE research and development under the Nuclear Hydrogen Initiative. The INL HTE program has included small-scale experiments, detailed computational modeling, system modeling, and technology demonstration. Aspects of all of these activities are included in this report. In terms of technology demonstration, the INL successfully completed a 1000-hour test of the HTE Integrated Laboratory Scale (ILS) technology demonstration experiment during the fall of 2008. The HTE ILS achieved a hydrogen production rate in excess of 5.7 Nm3/hr, with a power consumption of 18 kW. This hydrogen production rate is far larger than has been demonstrated by any of the thermochemical or hybrid processes to date.

  2. Nanoporous, Metal Carbide, Surface Diffusion Membranes for High Temperature Hydrogen Separations

    SciTech Connect

    Way, J.; Wolden, Colin

    2013-09-30

    Colorado School of Mines (CSM) developed high temperature, hydrogen permeable membranes that contain no platinum group metals with the goal of separating hydrogen from gas mixtures representative of gasification of carbon feedstocks such as coal or biomass in order to meet DOE NETL 2015 hydrogen membrane performance targets. We employed a dual synthesis strategy centered on transition metal carbides. In the first approach, novel, high temperature, surface diffusion membranes based on nanoporous Mo{sub 2}C were fabricated on ceramic supports. These were produced in a two step process that consisted of molybdenum oxide deposition followed by thermal carburization. Our best Mo{sub 2}C surface diffusion membrane achieved a pure hydrogen flux of 367 SCFH/ft{sup 2} at a feed pressure of only 20 psig. The highest H{sub 2}/N{sub 2} selectivity obtained with this approach was 4.9. A transport model using “dusty gas” theory was derived to describe the hydrogen transport in the Mo{sub 2}C coated, surface diffusion membranes. The second class of membranes developed were dense metal foils of BCC metals such as vanadium coated with thin (< 60 nm) Mo{sub 2}C catalyst layers. We have fabricated a Mo{sub 2}C/V composite membrane that in pure gas testing delivered a H{sub 2} flux of 238 SCFH/ft{sup 2} at 600 °C and 100 psig, with no detectable He permeance. This exceeds the 2010 DOE Target flux. This flux is 2.8 times that of pure Pd at the same membrane thickness and test conditions and over 79% of the 2015 flux target. In mixed gas testing we achieved a permeate purity of ≥99.99%, satisfying the permeate purity milestone, but the hydrogen permeance was low, ~0.2 SCFH/ft{sup 2}.psi. However, during testing of a Mo{sub 2}C coated Pd alloy membrane with DOE 1 feed gas mixture a hydrogen permeance of >2 SCFH/ft{sup 2}.psi was obtained which was stable during the entire test, meeting the permeance associated with the 2010 DOE target flux. Lastly, the Mo{sub 2}C/V composite

  3. Red soil as a regenerable sorbent for high temperature removal of hydrogen sulfide from coal gas.

    PubMed

    Ko, Tzu-Hsing; Chu, Hsin; Lin, Hsiao-Ping; Peng, Ching-Yu

    2006-08-25

    In this study, hydrogen sulfide (H(2)S) was removed from coal gas by red soil under high temperature in a fixed-bed reactor. Red soil powders were collected from the northern, center and southern of Taiwan. They were characterized by XRPD, porosity analysis and DCB chemical analysis. Results show that the greater sulfur content of LP red soils is attributed to the higher free iron oxides and suitable sulfidation temperature is around 773K. High temperature has a negative effect for use red soil as a desulfurization sorbent due to thermodynamic limitation in a reduction atmosphere. During 10 cycles of regeneration, after the first cycle the red soil remained stable with a breakthrough time between 31 and 36 min. Hydrogen adversely affects sulfidation reaction, whereas CO exhibits a positive effect due to a water-shift reaction. COS was formed during the sulfidation stage and this was attributed to the reaction of H(2)S and CO. Results of XRPD indicated that, hematite is the dominant active species in fresh red soil and iron sulfide (FeS) is a product of the reaction between hematite and hydrogen sulfide in red soils. The spinel phase FeAl(2)O(4) was found during regeneration, moreover, the amount of free iron oxides decreased after regeneration indicating the some of the free iron oxide formed a spinel phase, further reducting the overall desulfurization efficiency. PMID:16469434

  4. System Evaluations and Life-Cycle Cost Analyses for High-Temperature Electrolysis Hydrogen Production Facilities

    SciTech Connect

    Edwin A. Harvego; James E. O'Brien; Michael G. McKellar

    2012-05-01

    This report presents results of system evaluations and lifecycle cost analyses performed for several different commercial-scale high-temperature electrolysis (HTE) hydrogen production concepts. The concepts presented in this report rely on grid electricity and non-nuclear high-temperature process heat sources for the required energy inputs. The HYSYS process analysis software was used to evaluate both central plant designs for large-scale hydrogen production (50,000 kg/day or larger) and forecourt plant designs for distributed production and delivery at about 1,500 kg/day. The HYSYS software inherently ensures mass and energy balances across all components and it includes thermodynamic data for all chemical species. The optimized designs described in this report are based on analyses of process flow diagrams that included realistic representations of fluid conditions and component efficiencies and operating parameters for each of the HTE hydrogen production configurations analyzed. As with previous HTE system analyses performed at the INL, a custom electrolyzer model was incorporated into the overall process flow sheet. This electrolyzer model allows for the determination of the average Nernst potential, cell operating voltage, gas outlet temperatures, and electrolyzer efficiency for any specified inlet steam, hydrogen, and sweep-gas flow rates, current density, cell active area, and external heat loss or gain. The lifecycle cost analyses were performed using the H2A analysis methodology developed by the Department of Energy (DOE) Hydrogen Program. This methodology utilizes spreadsheet analysis tools that require detailed plant performance information (obtained from HYSYS), along with financial and cost information to calculate lifecycle costs. There are standard default sets of assumptions that the methodology uses to ensure consistency when comparing the cost of different production or plant design options. However, these assumptions may also be varied within the

  5. Spectroscopic Studies of the Vibrational and Electronic Properties of Hydrogen at High Pressure-Temperature Conditions

    SciTech Connect

    Goncharov, A F; Gregoryanz, E; Hemley, R J; Mao, H K

    2003-02-04

    The behavior of hydrogen at high densities has been widely explored in recent years both experimentally and theoretically, yielding a wealth of information on the material (e.g., Ref. 1). Detailed information has been obtained from static compression experiments generally limited to low-temperature studies (<300 K) and maximum pressures of {approx}300 GPa (e.g., Refs. [2,3]). However, there are now numerous questions regarding the behavior of hydrogen at high pressures and temperatures, results that have important implications for both fundamental physics and planetary science. We report here [2] Raman scattering and visible to near-infrared absorption spectra of solid hydrogen under static pressure up to 285 GPa at 85-140 K. We obtain pressure dependences of vibron and phonon modes in agreement with previously determined to lower pressures. The results indicate the stability of the ordered molecular phase III to the highest pressure reached and provide constraints on the insulator-to-metal transition pressure. Extrapolations of the vibron and phonon frequencies suggest transformation to a monoatomic state below 495 GPa. On the other hand, considerations of the absorption edge indicate the pressure of metallization at 325-385 GPa on the basis of tentative extrapolation of the direct band gap energy. Although complicated by affects of stressed-induced diamond absorption and possible differences between the behavior of the direct and indirect gap, there appears to be an emerging consistence between various experimental and theoretical results, with a predicted transition at 325-495 GPa. We also report high P-T Raman measurements of solid and fluid hydrogen to above 1100 K and to 155 GPa [4]. These conditions, which were previously inaccessible by static compression experiments, provide new insight into the behavior of the material under extreme conditions. The data give a direct measure of the melting curve (Fig. 1) that extends previous optical investigations by up

  6. Feasibility study on high-temperature sorption of hydrogen sulfide by natural soils.

    PubMed

    Ko, Tzu-Hsing; Chu, Hsin; Tseng, Jeou-Jen

    2006-08-01

    In this study, seven natural soils were tested for the sorption of hydrogen sulfide from coal gasification gas at high temperature. Results indicate that the LP natural soil has the best performance and the highest sulfur sorption capacity. After extracting free iron oxides, most natural soils have no sorption efficiency. The free iron oxides, therefore, proved to be the major components that react with hydrogen sulfide to form iron sulfides. The sulfur sorption capacity, either determined by EA or breakthrough time, is very close to the theoretical value based on the stoichiometric calculation with the content of free iron oxides. Moreover, the presence of CO is a positive effect while H2 is a negative effect. This can be explained via the water-shift reaction. On the basis of the results of temperature-programmed sulfidation (TPS), the starting temperature for the sorption of hydrogen sulfide is between 623-673 K. From the analyses of temperature-programmed oxidation (TPO) and XPS, the iron polysulfides are the major products and approximately 90% regeneration efficiency can be theoretically achieved while the temperature is controlled higher than 813 K. In the regeneration tests, the results show that the LP natural soil can be regenerated and thus reused after the oxidation process. No significant degeneration occurs on the LP natural soil after five sorption/regeneration cycles. The sulfur sorption capacity of the tenth regenerated soil can be achieved at least 80% compared to the fresh one. The experimental analyzed SO2 concentration from the regeneration process is almost identical to the theoretical calculated equilibrium concentration of the process. Maghemite is the main product after the regeneration process. PMID:16527331

  7. Thermodynamics of hydrogen-helium mixtures at high pressure and finite temperature

    NASA Technical Reports Server (NTRS)

    Hubbard, W. B.

    1972-01-01

    A technique is reviewed for calculating thermodynamic quantities for mixtures of light elements at high pressure, in the metallic state. Ensemble averages are calculated with Monte Carlo techniques and periodic boundary conditions. Interparticle potentials are assumed to be coulombic, screened by the electrons in dielectric function theory. This method is quantitatively accurate for alloys at pressures above about 10 Mbar. An alloy of equal parts hydrogen and helium by mass appears to remain liquid and mixed for temperatures above about 3000 K, at pressures of about 15 Mbar. The additive volume law is satisfied to within about 10%, but the Gruneisen equation of state gives poor results. A calculation at 1300 K shows evidence of a hydrogen-helium phase separation.

  8. High-temperature hydrogen-air-steam detonation experiments in the BNL small-scale development apparatus

    SciTech Connect

    Ciccarelli, G.; Ginsburg, T.; Boccio, J.; Economos, C.; Finfrock, C.; Gerlach, L.; Sato, K.; Kinoshita, M.

    1994-08-01

    The Small-Scale Development Apparatus (SSDA) was constructed to provide a preliminary set of experimental data to characterize the effect of temperature on the ability of hydrogen-air-steam mixtures to undergo detonations and, equally important, to support design of the larger scale High-Temperature Combustion Facility (HTCF) by providing a test bed for solution of a number of high-temperature design and operational problems. The SSDA, the central element of which is a 10-cm inside diameter, 6.1-m long tubular test vessel designed to permit detonation experiments at temperatures up to 700K, was employed to study self-sustained detonations in gaseous mixtures of hydrogen, air, and steam at temperatures between 300K and 650K at a fixed initial pressure of 0.1 MPa. Hydrogen-air mixtures with hydrogen composition from 9 to 60 percent by volume and steam fractions up to 35 percent by volume were studied for stoichiometric hydrogen-air-steam mixtures. Detonation cell size measurements provide clear evidence that the effect of hydrogen-air gas mixture temperature, in the range 300K-650K, is to decrease cell size and, hence, to increase the sensitivity of the mixture to undergo detonations. The effect of steam content, at any given temperature, is to increase the cell size and, thereby, to decrease the sensitivity of stoichiometric hydrogen-air mixtures. The hydrogen-air detonability limits for the 10-cm inside diameter SSDA test vessel, based upon the onset of single-head spin, decreased from 15 percent hydrogen at 300K down to between 9 and 10 percent hydrogen at 650K. The one-dimensional ZND model does a very good job at predicting the overall trends in the cell size data over the range of hydrogen-air-steam mixture compositions and temperature studied in the experiments.

  9. Permeation of hydrogen in hastelloy C-276 alloy at high temperature

    SciTech Connect

    Zhang, D.; Liu, W.; Qian, Y.; Que, J.

    2015-03-15

    Tritium is generated by the interaction of neutrons with the lithium and beryllium in the molten salt reactors (MSRs), which use FLiBe as one of solvents of fluoride fuel. Tritium as by-product in the MSRs is an important safety issue because it could easily diffuse into environment through high temperature heat exchangers. The experimental technique of gas driven permeation has been used to investigate the transport parameter of hydrogen in Hastelloy C-276 which is considered as one of the candidate for structure materials. The measurements were carried out at the temperature range of 400-800 Celsius degrees with hydrogen loading pressures ranging from 5*10{sup 3} to 4*10{sup 4} Pa. The H diffusive transport parameters for Hastelloy C-276 follow an Arrhenius law in this temperature range. Regarding diffusivity and Sieverts' constant, Hastelloy C-276 has lower values compared with Ni201 alloy. The possible reason may be the trapping effects, which were formed by the alloying elements of Mo and Cr in the matrix. At the same time, the thin oxidation layer formed by the high Cr content could lead to a slower dissociation process of H{sub 2} at the surface. (authors)

  10. Separation Requirements for a Hydrogen Production Plant and High-Temperature Nuclear Reactor

    SciTech Connect

    Curtis Smith; Scott Beck; William Galyean

    2006-06-01

    This paper presents an overview of the engineering methods, models, and results used in an evaluation for locating a hydrogen production facility near a proposed next-generation nuclear power plant. Standard probabilistic safety assessment methodologies were used to answer the risk-related questions for a combined nuclear and chemical facility: what can go wrong? how likely is it to happen? and what are the consequences of it happening? As part of answering these questions, a model was developed suitable for determining the distances separating a hydrogen-production process and nuclear plant structures. The objective of the model-development and analysis is to answer key safety questions relating to the placement of one or more hydrogen production plants in the vicinity of a high-temperature nuclear reactor. From a thermal-hydraulic efficiency standpoint, close proximity of the two facilities is beneficial. Safety and regulatory implications, however, force the separation to be increased, perhaps substantially. The likelihood of obtaining a permit to construct and build such as facility in the United States without answering these safety questions is uncertain. The quantitative analysis performed and described in this paper offers a scoping mechanism to determine key parameters relating to the development of a nuclear-based hydrogen production facility. The calculations indicate that when the facilities are less than 100 m apart, the core damage frequency is large enough (greater than 1E-6/yr) to become problematic in a risk-informed environment. However, a variety of design modifications (blast-deflection barriers, for example) could significantly reduce risk and should be further explored as design of the hydrogen production facility evolves.

  11. Separation Requirements for a Hydrogen Production Plant and High-Temperature Nuclear Reactor

    SciTech Connect

    Curtis Smith; Scott Beck; Bill Galyean

    2005-09-01

    This report provides the methods, models, and results of an evaluation for locating a hydrogen production facility near a nuclear power plant. In order to answer the risk-related questions for this combined nuclear and chemical facility, we utilized standard probabilistic safety assessment methodologies to answer three questions: what can happen, how likely is it, and what are the consequences? As part of answering these questions, we developed a model suitable to determine separation distances for hydrogen process structures and the nuclear plant structures. Our objective of the model-development and analysis is to answer key safety questions related to the placement of one or more hydrogen production plants in the vicinity of a high-temperature nuclear reactor. From a thermal-hydraulic standpoint we would like the two facilities to be quite close. However, safety and regulatory implications force the separation distance to be increased, perhaps substantially. Without answering these safety questions, the likelihood for obtaining a permit to construct and build such as facility in the U.S. would be questionable. The quantitative analysis performed for this report provides us with a scoping mechanism to determine key parameters related to the development of a nuclear-based hydrogen production facility. From our calculations, we estimate that when the separation distance is less than 100m, the core damage frequency is large enough (greater than 1E-6/yr) to become problematic in a risk-informed environment. However, a variety of design modifications, for example blast-deflection barriers, were explored to determine the impact of potential mitigating strategies. We found that these mitigating cases may significantly reduce risk and should be explored as the design for the hydrogen production facility evolves.

  12. System Analyses of High and Low-Temperature Interface Designs for a Nuclear-Driven High-Temperature Electrolysis Hydrogen Production Plant

    SciTech Connect

    E. A. Harvego; J. E. O'Brien

    2009-07-01

    As part of the Next Generation Nuclear Plant (NGNP) project, an evaluation of a low-temperature heat-pump interface design for a nuclear-driven high-temperature electrolysis (HTE) hydrogen production plant was performed using the UniSim process analysis software. The lowtemperature interface design is intended to reduce the interface temperature between the reactor power conversion system and the hydrogen production plant by extracting process heat from the low temperature portion of the power cycle rather than from the high-temperature portion of the cycle as is done with the current Idaho National Laboratory (INL) reference design. The intent of this design change is to mitigate the potential for tritium migration from the reactor core to the hydrogen plant, and reduce the potential for high temperature creep in the interface structures. The UniSim model assumed a 600 MWt Very-High Temperature Reactor (VHTR) operating at a primary system pressure of 7.0 MPa and a reactor outlet temperature of 900°C. The lowtemperature heat-pump loop is a water/steam loop that operates between 2.6 MPa and 5.0 MPa. The HTE hydrogen production loop operated at 5 MPa, with plant conditions optimized to maximize plant performance (i.e., 800°C electrolysis operating temperature, area specific resistance (ASR) = 0.4 ohm-cm2, and a current density of 0.25 amps/cm2). An air sweep gas system was used to remove oxygen from the anode side of the electrolyzer. Heat was also recovered from the hydrogen and oxygen product streams to maximize hydrogen production efficiencies. The results of the UniSim analysis showed that the low-temperature interface design was an effective heat-pump concept, transferring 31.5 MWt from the low-temperature leg of the gas turbine power cycle to the HTE process boiler, while consuming 16.0 MWe of compressor power. However, when this concept was compared with the current INL reference direct Brayton cycle design and with a modification of the reference design to

  13. Nanocomposite thin films for high temperature optical gas sensing of hydrogen

    SciTech Connect

    Ohodnicki, Jr., Paul R.; Brown, Thomas D.

    2013-04-02

    The disclosure relates to a plasmon resonance-based method for H.sub.2 sensing in a gas stream at temperatures greater than about 500.degree. C. utilizing a hydrogen sensing material. The hydrogen sensing material is comprised of gold nanoparticles having an average nanoparticle diameter of less than about 100 nanometers dispersed in an inert matrix having a bandgap greater than or equal to 5 eV, and an oxygen ion conductivity less than approximately 10.sup.-7 S/cm at a temperature of 700.degree. C. Exemplary inert matrix materials include SiO.sub.2, Al.sub.2O.sub.3, and Si.sub.3N.sub.4 as well as modifications to modify the effective refractive indices through combinations and/or doping of such materials. At high temperatures, blue shift of the plasmon resonance optical absorption peak indicates the presence of H.sub.2. The method disclosed offers significant advantage over active and reducible matrix materials typically utilized, such as yttria-stabilized zirconia (YSZ) or TiO.sub.2.

  14. High temperature oxidation of UO 2 in steam-hydrogen mixtures

    NASA Astrophysics Data System (ADS)

    Abrefah, J.; Aguiar Braid, A. de; Wang, W.; Khalil, Y.; Olander, D. R.

    1994-01-01

    An experimental study of UO 2 oxidation in pure steam and in H 2O/Ar/H 2 mixtures was conducted in a continuously recording thermogravimetric apparatus in the temperature range 1273-1623 K at one atmosphere system pressure. Two surface reaction models were utilized in the analysis of the data: the phenomenological model assumes the reaction rate to be proportional to the deviation of the oxygen concentration in the solid from the equilibrium value established by the ambient gas. Analysis of the results show that the phenomenological model does not fit the experimental data for pure steam, but the fit is good for H 2O/Ar/H 2 mixtures. The mechanistic model is based on the rate-controlling step of water dissociation at the solid surface. It provides a very good fit to all of the data. As long as the pressure is 1 atm, either of the models can be used to predict fuel oxidation in severe accidents because the ambient gas invariably contains hydrogen produced by Zircaloy corrosion. However, the kinetics of oxidation in high-pressure steam-hydrogen mixtures is still uncertain. Evidence of uranium volatilization and preferential etching at the grain boundaries at high temperatures were observed.

  15. Hydrogen production by high-temperature water splitting using electron-conducting membranes

    DOEpatents

    Lee, Tae H.; Wang, Shuangyan; Dorris, Stephen E.; Balachandran, Uthamalingam

    2004-04-27

    A device and method for separating water into hydrogen and oxygen is disclosed. A first substantially gas impervious solid electron-conducting membrane for selectively passing hydrogen is provided and spaced from a second substantially gas impervious solid electron-conducting membrane for selectively passing oxygen. When steam is passed between the two membranes at disassociation temperatures the hydrogen from the disassociation of steam selectively and continuously passes through the first membrane and oxygen selectively and continuously passes through the second membrane, thereby continuously driving the disassociation of steam producing hydrogen and oxygen.

  16. High-pressure, ambient temperature hydrogen storage in metal-organic frameworks and porous carbon

    NASA Astrophysics Data System (ADS)

    Beckner, Matthew; Dailly, Anne

    2014-03-01

    We investigated hydrogen storage in micro-porous adsorbents at ambient temperature and pressures up to 320 bar. We measured three benchmark adsorbents: two metal-organic frameworks, Cu3(1,3,5-benzenetricarboxylate)2 [Cu3(btc)2; HKUST-1] and Zn4O(1,3,5-benzenetribenzoate)2 [Zn4O(btb)2; MOF-177], and the activated carbon MSC-30. In this talk, we focus on adsorption enthalpy calculations using a single adsorption isotherm. We use the differential form of the Claussius-Clapeyron equation applied to the Dubinin-Astakhov adsorption model to calculate adsorption enthalpies. Calculation of the adsorption enthalpy in this way gives a temperature independent enthalpy of 5-7 kJ/mol at the lowest coverage for the three materials investigated. Additionally, we discuss the assumptions and corrections that must be made when calculating adsorption isotherms at high-pressure and adsorption enthalpies.

  17. System Evaluation and Economic Analysis of a Nuclear Reactor Powered High-Temperature Electrolysis Hydrogen-Production Plant

    SciTech Connect

    E. A. Harvego; M. G. McKellar; M. S. Sohal; J. E. O'Brien; J. S. Herring

    2010-06-01

    A reference design for a commercial-scale high-temperature electrolysis (HTE) plant for hydrogen production was developed to provide a basis for comparing the HTE concept with other hydrogen production concepts. The reference plant design is driven by a high-temperature helium-cooled nuclear reactor coupled to a direct Brayton power cycle. The reference design reactor power is 600 MWt, with a primary system pressure of 7.0 MPa, and reactor inlet and outlet fluid temperatures of 540°C and 900°C, respectively. The electrolysis unit used to produce hydrogen includes 4,009,177 cells with a per-cell active area of 225 cm2. The optimized design for the reference hydrogen production plant operates at a system pressure of 5.0 MPa, and utilizes an air-sweep system to remove the excess oxygen that is evolved on the anode (oxygen) side of the electrolyzer. The inlet air for the air-sweep system is compressed to the system operating pressure of 5.0 MPa in a four-stage compressor with intercooling. The alternating current (AC) to direct current (DC) conversion efficiency is 96%. The overall system thermal-to-hydrogen production efficiency (based on the lower heating value of the produced hydrogen) is 47.1% at a hydrogen production rate of 2.356 kg/s. An economic analysis of this plant was performed using the standardized H2A Analysis Methodology developed by the Department of Energy (DOE) Hydrogen Program, and using realistic financial and cost estimating assumptions. The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a competitive cost. A cost of $3.23/kg of hydrogen was calculated assuming an internal rate of return of 10%.

  18. Nuclear Microprobe using Elastic Recoil Detection (ERD) for Hydrogen Profiling in High Temperature Protonic Conductors

    NASA Technical Reports Server (NTRS)

    Berger, Pascal; Sayir, Ali; Berger, Marie-Helene

    2004-01-01

    The interaction between hydrogen and various high temperature protonic conductors (HTPC) has not been clearly understood due to poor densification and unreacted secondary phases. the melt-processing technique is used in producing fully dense simple SrCe(0.9)Y (0.10) O(3-delta) and complex Sr3Ca(1+x)Nb(2+x)O(9-delta) perovskites that can not be achieved by solid-state sintering. the possibilities of ion beam analysis have been investigated to quantify hydrogen distribution in HTPC perovskites subjected to water heat treatment. Nuclear microprobe technique is based on the interactions of a focused ion beam of MeV light ions (H-1, H-2, He-3, He-4,.) with the sample to be analyzed to determine local elemental concentrations at the cubic micrometer scale, the elastic recoil detection analysis technique (ERDA) has been carried out using He-4(+) microbeams and detecting the resulting recoil protons. Mappings of longitudinal sections of water treated SrCeO3 and Sr(Ca(1/3)Nb(2/3))O3 perovskites have been achieved, the water treatment strongly alters the surface of simple SrCe(0.9)Y(0.10)O(3-delta) perovskite. From Rutherford Back Scattering measurements (RBS), both Ce depletion and surface re-deposition is evidenced. the ERDA investigations on water treated Sr3Ca(1+x)Nb(2+x)O(9-delta) perovskite did not exhibit any spatial difference for the hydrogen incorporation from the surface to the centre. the amount of hydrogen incorporation for Sr3Ca(1+x)Nb(2+x)O(9-delta) was low and required further development of two less conventional techniques, ERDA in forward geometry and forward elastic diffusion H-1(p,p) H-1 with coincidence detection.

  19. Hydrogen detonation and detonation transition data from the High-Temperature Combustion Facility

    SciTech Connect

    Ciccarelli, G.; Boccio, J.L.; Ginsberg, T.; Finfrock, C.; Gerlach, L.; Tagawa, H.; Malliakos, A.

    1995-12-31

    The BNL High-Temperature Combustion Facility (HTCF) is an experimental research tool capable of investigating the effects of initial thermodynamic state on the high-speed combustion characteristic of reactive gas mixtures. The overall experimental program has been designed to provide data to help characterize the influence of elevated gas-mixture temperature (and pressure) on the inherent sensitivity of hydrogen-air-steam mixtures to undergo detonation, on the potential for flames accelerating in these mixtures to transition into detonations, on the effects of gas venting on the flame-accelerating process, on the phenomena of initiation of detonations in these mixtures by jets of hot reactant product,s and on the capability of detonations within a confined space to transmit into another, larger confined space. This paper presents results obtained from the completion of two of the overall test series that was designed to characterize high-speed combustion phenomena in initially high-temperature gas mixtures. These two test series are the intrinsic detonability test series and the deflagration-to-detonation (DDT) test series. A brief description of the facility is provided below.

  20. Hydrogen detonation and detonation transition data from the High-Temperature Combustion Facility

    SciTech Connect

    Ciccarelli, G.; Boccio, J.L.; Ginsberg, T.; Finfrock, C.

    1996-03-01

    The BNL High-Temperature Combustion Facility (HTCF) is an experimental research tool capable of investigating the effects of initial thermodynamic state on the high-speed combustion characteristic of reactive gas mixtures. The overall experimental program has been designed to provide data to help characterize the influence of elevated gas-mixture temperature (and pressure) on the inherent sensitivity of hydrogen-air-steam mixtures to undergo detonation, on the potential for flames accelerating in these mixtures to transition into detonations, on the effects of gas venting on the flame-accelerating process, on the phenomena of initiation of detonations in these mixtures by jets of hot reactant products, and on the capability of detonations within a confined space to transmit into another, larger confined space. This paper presents results obtained from the completion of two of the overall test series that was designed to characterize high-speed combustion phenomena in initially high-temperature gas mixtures. These two test series are the intrinsic detonability test series and the deflagration-to-detonation (DDT) test series. A brief description of the facility is provided below.

  1. Detonation cell size measurements in high-temperature hydrogen-air-steam mixtures at the BNL high-temperature combustion facility

    SciTech Connect

    Ciccarelli, G.; Ginsberg, T.; Boccio, J.L.

    1997-11-01

    The High-Temperature Combustion Facility (HTCF) was designed and constructed with the objective of studying detonation phenomena in mixtures of hydrogen-air-steam at initially high temperatures. The central element of the HTCF is a 27-cm inner-diameter, 21.3-m long cylindrical test vessel capable of being heating to 700K {+-} 14K. A unique feature of the HTCF is the {open_quotes}diaphragmless{close_quotes} acetylene-oxygen gas driver which is used to initiate the detonation in the test gas. Cell size measurements have shown that for any hydrogen-air-steam mixture, increasing the initial mixture temperature, in the range of 300K to 650K, while maintaining the initial pressure of 0.1 MPa, decreases the cell size and thus makes the mixture more detonable. The effect of steam dilution on cell size was tested in stoichiometric and off-stoichiometric (e.g., equivalence ratio of 0.5) hydrogen-air mixtures. Increasing the steam dilution in hydrogen-air mixtures at 0.1 MPa initial pressure increases the cell size, irrespective of initial temperature. It is also observed that the desensitizing effect of steam diminished with increased initial temperature. A 1-dimensional, steady-state Zel`dovich, von Neumann, Doring (ZND) model, with full chemical kinetics, has been used to predict cell size for hydrogen-air-steam mixtures at different initial conditions. Qualitatively the model predicts the overall trends observed in the measured cell size versus mixture composition and initial temperature and pressure. It was found that the proportionality constant used to predict detonation cell size from the calculated ZND model reaction zone varies between 10 and 100 depending on the mixture composition and initial temperature. 32 refs., 35 figs.

  2. Demonstration and System Analysis of High Temperature Steam Electrolysis for Large-Scale Hydrogen Production Using SOFCs

    SciTech Connect

    Michael G. McKellar; James E. O'Brien; Carl M. Stoots; J. Stephen Herring

    2008-07-01

    At the Idaho National Engineering Laboratory, an integrated laboratory scale (ILS), 15 kW high-temperature electrolysis (HTE) facility has been developed under the U.S. Department of Energy Nuclear Hydrogen Initiative. Initial operation of this facility resulted in over 400 hours of operation with an average hydrogen production rate of approximately 0.9 Nm3/hr. The integrated laboratory scale facility is designed to address larger-scale issues such as thermal management (feed-stock heating, high-temperature gas handling), multiple-stack hot-zone design, multiple-stack electrical configurations, and other “integral” issues. Additionally, a reference process model of a commercial-scale high-temperature electrolysis plant for hydrogen production has been developed. The reference plant design is driven by a 600 megawatt thermal high-temperature helium-cooled reactor coupled to a direct Brayton power cycle. The electrolysis unit used to produce hydrogen consists of 4.01×106 cells with a per-cell active area of 225 cm2. A nominal cell area-specific resistance, ASR, value of 0.4 Ohm•cm2 with a current density of 0.25 A/cm2 was used, and isothermal boundary conditions were assumed. The overall system thermal-to-hydrogen production efficiency (based on the low heating value of the produced hydrogen) is 47.1% at a hydrogen production rate of 2.36 kg/s with the high-temperature helium-cooled reactor concept. This paper documents the initial operation of the ILS, with experimental details about heat-up, initial stack performance, as well as long-term operation and stack degradation. The paper will also present the optimized design for the reference nuclear-driven HTE hydrogen production plant which may be compared with other hydrogen production methods and power cycles to evaluate relative performance characteristics and plant economics.

  3. NanoCapillary Network Proton Conducting Membranes for High Temperature Hydrogen/Air Fuel Cells

    SciTech Connect

    Pintauro, Peter

    2012-07-09

    The objective of this proposal is to fabricate and characterize a new class of NanoCapillary Network (NCN) proton conducting membranes for hydrogen/air fuel cells that operate under high temperature, low humidity conditions. The membranes will be intelligently designed, where a high density interconnecting 3-D network of nm-diameter electrospun proton conducting polymer fibers is embedded in an inert (uncharged) water/gas impermeable polymer matrix. The high density of fibers in the resulting mat and the high ion-exchange capacity of the fiber polymer will ensure high proton conductivity. To further enhance water retention, molecular silica will be added to the sulfonated polymer fibers. The uncharged matrix material will control water swelling of the high ion-exchange capacity proton conducting polymer fibers and will impart toughness to the final nanocapillary composite membrane. Thus, unlike other fuel cell membranes, the role of the polymer support matrix will be decoupled from that of the proton-conducting channels. The expected final outcome of this 5-year project is the fabrication of fuel cell membranes with properties that exceed the DOE’s technical targets, in particular a proton conductivity of 0.1 S/cm at a temperature less than or equal to120°C and 25-50% relative humidity.

  4. PROGRESS IN HIGH-TEMPERATURE ELECTROLYSIS FOR HYDROGEN PRODUCTION USING PLANAR SOFC TECHNOLOGY

    SciTech Connect

    O'Brien, J. E.; Herring, J. S.; Stoots, C. M.; Hawkes, G. L.; Hartvigsen, J., J.; Mehrdad Shahnam

    2005-04-01

    A research program is under way at the Idaho National Laboratory to assess the performance of solid-oxide cells operating in the steam electrolysis mode for hydrogen production over a temperature range of 800 to 900ºC. The research program includes both experimental and modeling activities. Selected results from both activities are presented in this paper. Experimental results were obtained from a ten-cell planar electrolysis stack, fabricated by Ceramatec , Inc. The electrolysis cells are electrolyte-supported, with scandia-stabilized zirconia electrolytes (~140 µm thick), nickel-cermet steam/hydrogen electrodes, and manganite air-side electrodes. The metallic interconnect plates are fabricated from ferritic stainless steel. The experiments were performed over a range of steam inlet mole fractions (0.1 - 0.6), gas flow rates (1000 - 4000 sccm), and current densities (0 to 0.38 A/cm2). Hydrogen production rates up to 90 Normal liters per hour were demonstrated. Stack performance is shown to be dependent on inlet steam flow rate. A three-dimensional computational fluid dynamics (CFD) model was also created to model high-temperature steam electrolysis in a planar solid oxide electrolysis cell (SOEC). The model represents a single cell as it would exist in the experimental electrolysis stack. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT1. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean model results are shown to compare favorably with

  5. Properties of materials in high pressure hydrogen at cryogenic, room, and elevated temperatures

    NASA Technical Reports Server (NTRS)

    Harris, J. A., Jr.; Vanwanderham, M. C.

    1973-01-01

    Various tests were conducted to determine the mechanical properties of 12 alloys that are commonly used or proposed for use in pressurized gaseous hydrogen or hydrogen containing environments. Properties determined in the hydrogen environments were compared to properties determined in a pure helium environment at the same conditions to establish environmental degradation. The specific mechanical properties tested include: high-cycle fatigue, low-cycle fatigue, fracture mechanics, creep-rupture, and tensile.

  6. Retention of Hydrogen in FCC Metals Irradiated at Temperatures Leading to High Densities of Bubbles or Voids

    SciTech Connect

    Garner, Francis A.; Simonen, Edward P.; Oliver, Brian M.; Greenwood, Lawrence R.; Grossbeck, M L.; Wolfer, W. G.; Scott, P M.

    2006-09-15

    Large amounts of hydrogen and helium are generated in structural metals in accelerator-driven systems. It is shown that under certain conditions, hydrogen can be stored in irradiated nickel and stainless steels at levels strongly in excess of that predicted by Sieverts Law. These conditions are first, the availability of hydrogen from various radiolytic and environmental sources and second, the formation of radiation-induced cavities to store hydrogen. These cavities can be highly pressurized bubbles or under-pressurized voids, with concurrent helium in the cavities at either low or very high levels. Transmutant sources of hydrogen are often insufficient to pressurize these cavities, and therefore environmental sources are required. The stored hydrogen appears to be stable for many years at room temperature. A conceptual model to describe such behavior requires the continuous generation of hydrogen from (n, p) reactions and possibly other radiolytic sources which can create a supersaturation of hydrogen in the metal, leading to the pressurization of voids and helium bubbles. Once captured in a bubble, the hydrogen is assumed to be in molecular form. Dissolution back into the metal requires chemisorption and dissociation on the bubble surface. Both of these processes have large activation barriers, particularly when oxygen, carbohydrates, and other impurities poison the bubble surface. However, these chemisorbed poisons may reduce but not entirely restrict the ingress or egress of atomic hydrogen.

  7. Hydrogen sulfide mediates nicotine biosynthesis in tobacco (Nicotiana tabacum) under high temperature conditions.

    PubMed

    Chen, Xiaodong; Chen, Qian; Zhang, Xiaoming; Li, Ruijing; Jia, Yujie; Ef, Abd Allah; Jia, Aiqun; Hu, Liwei; Hu, Xiangyang

    2016-07-01

    Hydrogen sulfide (H2S) acts as a signal to induce many physiological processes in plants, but its role in controlling the biosynthesis of secondary metabolites is not well established. In this study, we found that high temperature (HT) treatment induced nicotine biosynthesis in tobacco (Nicotiana tabacum) and promoted the rapid accumulation of H2S. Furthermore, HT triggered the biosynthesis of jasmonic acid (JA), a plant hormone that promotes nicotine biosynthesis. Suppression of the H2S signal using chemical inhibitors or via RNAi suppression of l-cysteine desulphydrase (L-CD) in transgenic plants, compromised JA production and nicotine biosynthesis under HT treatments, and these inhibitory effects could be reversed by applying exogenous H2S. Based on these data, we propose that H2S is an important trigger of nicotine biosynthesis in tobacco under HT conditions, and that H2S acts upstream of JA signaling by modulating the transcription of genes associated with JA biosynthesis. PMID:27035256

  8. The Effects of Water Vapor and Hydrogen on the High-Temperature Oxidation of Alloys

    SciTech Connect

    Mu, N; Jung, K; Yanar, N M; Pettit, F S; Holcomb, G R; Howard, B H; Meier, G H

    2013-06-01

    Essentially all alloys and coatings that are resistant to corrosion at high temperature require the formation of a protective (slowly-growing and adherent) oxide layer by a process known as selective oxidation. The fundamental understanding of this process has been developed over the years for exposure in pure oxygen or air. However, the atmospheres in most applications contain significant amounts of water vapor which can greatly modify the behavior of protective oxides. The development of oxy-fuel combustion systems in which fossil fuels are burned in a mixture of recirculated flue gas and oxygen, rather than in air, has caused renewed interest in the effects of water vapor and steam on alloy oxidation. The focus of this paper is on the ways the presence of water vapor can directly alter the selective oxidation process. The paper begins with a brief review of the fundamentals of selective oxidation followed by a description of recent experimental results regarding the effect of water vapor on the oxidation of a variety of chromia-forming alloys (Fe- and Ni-base) in the temperature range 600 to 700 °C. The atmospheres include air, air-H{sub 2}O, Ar-H{sub 2}O and Ar-H{sub 2}O-O{sub 2}. Then the behavior of alumina-forming alloys in H{sub 2}O-containing atmospheres is briefly described. As hydrogen is produced during oxidation of alloys in H{sub 2}O, it can be released back into the gas phase or injected into the metal (where it can diffuse through to the other side). Experiments in which hydrogen concentrations have been measured on both sides of thin specimens during oxidation by H{sub 2}O on only one side are described. Finally, it is attempted to catalogue the various experimental observations under a few general principles.

  9. Hydrogen production by high temperature water splitting using electron conducting membranes

    DOEpatents

    Balachandran, Uthamalingam; Wang, Shuangyan; Dorris, Stephen E.; Lee, Tae H.

    2006-08-08

    A device and method for separating water into hydrogen and oxygen is disclosed. A first substantially gas impervious solid electron-conducting membrane for selectively passing protons or hydrogen is provided and spaced from a second substantially gas impervious solid electron-conducting membrane for selectively passing oxygen. When steam is passed between the two membranes at dissociation temperatures the hydrogen from the dissociation of steam selectively and continuously passes through the first membrane and oxygen selectively and continuously passes through the second membrane, thereby continuously driving the dissociation of steam producing hydrogen and oxygen. The oxygen is thereafter reacted with methane to produce syngas which optimally may be reacted in a water gas shift reaction to produce CO2 and H2.

  10. Low Temperature and High Pressure Evaluation of Insulated Pressure Vessels for Cryogenic Hydrogen Storage

    SciTech Connect

    Aceves, S.; Martinez-Frias, J.; Garcia-Villazana, O.

    2000-06-25

    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH{sub 2}) or ambient-temperature compressed hydrogen (CH{sub 2}). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Required future tests are described that will prove that no technical barriers exist to the safe use of aluminum-fiber vessels at cryogenic temperatures.

  11. Economic Analysis of the Reference Design for a Nuclear-Driven High-Temperature-Electrolysis Hydrogen Production Plant

    SciTech Connect

    E. A. Harvego; M. G. McKellar; M. S. Sohal; J. E. O'Brien; J. S. Herring

    2008-01-01

    A reference design for a commercial-scale high-temperature electrolysis (HTE) plant for hydrogen production was developed to provide a basis for comparing the HTE concept with other hydrogen production concepts. The reference plant design is driven by a high-temperature helium-cooled reactor coupled to a direct Brayton power cycle. The reference design reactor power is 600 MWt, with a primary system pressure of 7.0 MPa, and reactor inlet and outlet fluid temperatures of 540°C and 900°C, respectively. The electrolysis unit used to produce hydrogen consists of 4,009,177 cells with a per-cell active area of 225 cm2. A nominal cell area-specific resistance, ASR, value of 0.4 Ohm•cm2 with a current density of 0.25 A/cm2 was used, and isothermal boundary conditions were assumed. The optimized design for the reference hydrogen production plant operates at a system pressure of 5.0 MPa, and utilizes an air-sweep system to remove the excess oxygen that is evolved on the anode side of the electrolyzer. The inlet air for the air-sweep system is compressed to the system operating pressure of 5.0 MPa in a four-stage compressor with intercooling. The alternating current, AC, to direct current, DC, conversion is 96%. The overall system thermal-to-hydrogen production efficiency (based on the low heating value of the produced hydrogen) is 47.12% at a hydrogen production rate of 2.356 kg/s. An economic analysis of the plant was also performed using the H2A Analysis Methodology developed by the Department of Energy (DOE) Hydrogen Program. The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a competitive cost using realistic financial and cost estimating assumptions. A required cost of $3.23 per kg of hydrogen produced was calculated assuming an internal rate of return of 10%. Approximately 73% of this cost ($2.36/kg) is the result of capital costs associated

  12. Butterfly valve with metal seals controls flow of hydrogen from cryogenic through high temperatures

    NASA Technical Reports Server (NTRS)

    Johnson, L. D.

    1967-01-01

    Butterfly valve with metal seals operates over a temperature range of minus 423 degrees to plus 440 degrees F with hydrogen as a medium and in a radiation environment. Media flow is controlled by an internal butterfly disk which is rotated by an actuation shaft.

  13. Optimized Flow Sheet for a Reference Commercial-Scale Nuclear-Driven High-Temperature Electrolysis Hydrogen Production Plant

    SciTech Connect

    M. G. McKellar; J. E. O'Brien; E. A. Harvego; J. S. Herring

    2007-11-01

    This report presents results from the development and optimization of a reference commercialscale high-temperature electrolysis (HTE) plant for hydrogen production. The reference plant design is driven by a high-temperature helium-cooled reactor coupled to a direct Brayton power cycle. The reference design reactor power is 600 MWt, with a primary system pressure of 7.0 MPa, and reactor inlet and outlet fluid temperatures of 540° C and 900°C, respectively. The electrolysis unit used to produce hydrogen consists of 4.176 × 10 6 cells with a per-cell active area of 225 cm2. A nominal cell area-specific resistance, ASR, value of 0.4 Ohm•cm2 with a current density of 0.25 A/cm2 was used, and isothermal boundary conditions were assumed. The optimized design for the reference hydrogen production plant operates at a system pressure of 5.0 MPa, and utilizes an air-sweep system to remove the excess oxygen that is evolved on the anode side of the electrolyzer. The inlet air for the air-sweep system is compressed to the system operating pressure of 5.0 MPa in a four-stage compressor with intercooling. The overall system thermal-to-hydrogen production efficiency (based on the low heating value of the produced hydrogen) is 49.07% at a hydrogen production rate of 2.45 kg/s with the high-temperature helium-cooled reactor concept. The information presented in this report is intended to establish an optimized design for the reference nuclear-driven HTE hydrogen production plant so that parameters can be compared with other hydrogen production methods and power cycles to evaluate relative performance characteristics and plant economics.

  14. Crack growth behavior of warm-rolled 316L austenitic stainless steel in high-temperature hydrogenated water

    NASA Astrophysics Data System (ADS)

    Choi, Kyoung Joon; Yoo, Seung Chang; Jin, Hyung-Ha; Kwon, Junhyun; Choi, Min-Jae; Hwang, Seong Sik; Kim, Ji Hyun

    2016-08-01

    To investigate the effects of warm rolling on the crack growth of 316L austenitic stainless steel, the crack growth rate was measured and the oxide structure was characterized in high-temperature hydrogenated water. The warm-rolled specimens showed a higher crack growth rate compared to the as-received specimens because the slip bands and dislocations produced during warm rolling served as paths for corrosion and cracking. The crack growth rate increased with the dissolved hydrogen concentration. This may be attributed to the decrease in performance and stability of the protective oxide layer formed on the surface of stainless steel in high-temperature water.

  15. Idaho National Laboratory Experimental Research In High Temperature Electrolysis For Hydrogen And Syngas Production

    SciTech Connect

    Carl M. Stoots; James E. O'Brien; J. Stephen Herring; Joseph J. Hartvigsen

    2008-09-01

    The Idaho National Laboratory (Idaho Falls, Idaho, USA), in collaboration with Ceramatec, Inc. (Salt Lake City, Utah, USA), is actively researching the application of solid oxide fuel cell technology as electrolyzers for large scale hydrogen and syngas production. This technology relies upon electricity and high temperature heat to chemically reduce a steam or steam / CO2 feedstock. Single button cell tests, multi-cell stack, as well as multi-stack testing has been conducted. Stack testing used 10 x 10 cm cells (8 x 8 cm active area) supplied by Ceramatec and ranged from 10 cell short stacks to 240 cell modules. Tests were conducted either in a bench-scale test apparatus or in a newly developed 5 kW Integrated Laboratory Scale (ILS) test facility. Gas composition, operating voltage, and operating temperature were varied during testing. The tests were heavily instrumented, and outlet gas compositions were monitored with a gas chromatograph. The ILS facility is currently being expanded to ~15 kW testing capacity (H2 production rate based upon lower heating value).

  16. Hydrogen Production via a High-Efficiency Low-Temperature Reformer

    SciTech Connect

    Paul KT Liu; Theo T. Tsotsis

    2006-05-31

    Fuel cells are promoted by the US government as a viable alternative for clean and efficient energy generation. It is anticipated that the fuel cell market will rise if the key technical barriers can be overcome. One of them is certainly fuel processing and purification. Existing fuel reforming processes are energy intensive, extremely complicated and capital intensive; these disadvantages handicap the scale-down of existing reforming process, targeting distributed or on-board/stationary hydrogen production applications. Our project involves the bench-scale demonstration of a high-efficiency low-temperature steam reforming process. Hydrogen production can be operated at 350 to 400ºC with our invention, as opposed to >800ºC of existing reforming. In addition, our proposed process improves the start-up deficiency of conventional reforming due to its low temperature operation. The objective of this project is to demonstrate the invented process concept via a bench scale unit and verify mathematical simulation for future process optimization study. Under this project, we have performed the experimental work to determine the adsorption isotherm, reaction kinetics, and membrane permeances required to perform the process simulation based upon the mathematical model developed by us. A ceramic membrane coated with palladium thin film fabricated by us was employed in this study. The adsorption isotherm for a selected hydrotalcite adsorbent was determined experimentally. Further, the capacity loss under cyclic adsorption/desorption was confirmed to be negligible. Finally a commercial steam reforming catalyst was used to produce the reaction kinetic parameters required for the proposed operating condition. With these input parameters, a mathematical simulation was performed to predict the performance of the invented process. According to our simulation, our invented hybrid process can deliver 35 to 55% methane conversion, in comparison with the 12 and 18-21% conversion of

  17. PALLADIUM/COPPER ALLOY COMPOSITE MEMBRANES FOR HIGH TEMPERATURE HYDROGEN SEPARATION

    SciTech Connect

    J. Douglas Way

    2004-08-31

    This report summarizes progress made during the first year of research funding from DOE Grant No. DE-FG26-03NT41792 at the Colorado School of Mines. The period of performance was September 1, 2003 through August of 2004. Composite membranes, consisting of a thin Pd alloy film supported on a porous substrate have been investigated as a means of reducing the membrane cost and improving H{sub 2} flux. An electroless plating technique was utilized to deposit subsequent layers of palladium and copper over zirconia and alumina-based microfilters. The composite membranes thus made were annealed and tested at temperatures ranging from 250 to 500 C, under very high feed pressures (up to 450 psig) using pure gases and gaseous mixtures containing H{sub 2}, CO, CO{sub 2}, H{sub 2}O and H{sub 2}S, with the purpose of determining the effects these variables had on the H{sub 2} permeation rate, selectivity and percent recovery. The inhibition caused by CO/CO{sub 2} gases on a 7 {micro}m thick Pd-Cu composite membrane was less than 17% over a wide range of compositions at 350 C. H{sub 2}S caused a strong inhibition of the H{sub 2} flux of the same Pd-Cu composite membrane, which is accentuated at levels of 100 ppm or higher. The membrane was exposed to 50 ppm three times without permanent damage. At higher H{sub 2}S levels, above 100 ppm the membrane suffered some physical degradation and its performances was severely affected. The use of sweep gases improved the hydrogen flux and recovery of a Pd-Cu composite membrane. Recently, we have been able to dramatically reduce the thickness of these Pd alloy membranes to approximately one micron. This is significant because at this thickness, it is the cost of the porous support that controls the materials cost of a composite Pd alloy membrane, not the palladium inventory. Very recent results show that the productivity of our membranes is very high, essentially meeting the DOE pure hydrogen flux target value set by the DOE Hydrogen

  18. HIGH-TEMPERATURE ELECTROLYSIS FOR LARGE-SCALE HYDROGEN AND SYNGAS PRODUCTION FROM NUCLEAR ENERGY – SYSTEM SIMULATION AND ECONOMICS

    SciTech Connect

    J. E. O'Brien; M. G. McKellar; E. A. Harvego; C. M. Stoots

    2009-05-01

    A research and development program is under way at the Idaho National Laboratory (INL) to assess the technological and scale-up issues associated with the implementation of solid-oxide electrolysis cell technology for efficient high-temperature hydrogen production from steam. This work is supported by the US Department of Energy, Office of Nuclear Energy, under the Nuclear Hydrogen Initiative. This paper will provide an overview of large-scale system modeling results and economic analyses that have been completed to date. System analysis results have been obtained using the commercial code UniSim, augmented with a custom high-temperature electrolyzer module. Economic analysis results were based on the DOE H2A analysis methodology. The process flow diagrams for the system simulations include an advanced nuclear reactor as a source of high-temperature process heat, a power cycle and a coupled steam electrolysis loop. Several reactor types and power cycles have been considered, over a range of reactor outlet temperatures. Pure steam electrolysis for hydrogen production as well as coelectrolysis for syngas production from steam/carbon dioxide mixtures have both been considered. In addition, the feasibility of coupling the high-temperature electrolysis process to biomass and coal-based synthetic fuels production has been considered. These simulations demonstrate that the addition of supplementary nuclear hydrogen to synthetic fuels production from any carbon source minimizes emissions of carbon dioxide during the production process.

  19. First principles simulation of a superionic phase of hydrogen fluoride (HF) at high pressures and temperatures

    SciTech Connect

    Goldman, N; Fried, L E

    2006-04-10

    The authors have conducted Ab initio molecular dynamics simulations of hydrogen fluoride (HF) at pressures of 5-66 GPa along the 900 K isotherm. They predict a superionic phase at 33 GPa, where the fluorine atoms are fixed in a bcc lattice while the hydrogen atoms diffuse rapidly with a diffusion constant of between 2 x 10{sup -5} and 5 x 10{sup -5} cm{sup 2}/s. They find that a transformation from asymmetric to symmetric hydrogen bonding occurs in HF at 66 GPa and 900 K. With superionic HF they have discovered a model system where symmetric hydrogen bonding occurs at experimentally achievable conditions. Given previous results on superionic H{sub 2}O[1,2,3] and NH{sub 3}[1], they conclude that high P,T superionic phases of electronegative element hydrides could be common.

  20. Reasons for high-temperature superconductivity in the electron–phonon system of hydrogen sulfide

    SciTech Connect

    Degtyarenko, N. N.; Mazur, E. A.

    2015-08-15

    We have calculated the electron and phonon spectra, as well as the densities of the electron and phonon states, of the stable orthorhombic structure of hydrogen sulfide SH{sub 2} in the pressure interval 100–180 GPa. It is found that at a pressure of 175 GPa, a set of parallel planes of hydrogen atoms is formed due to a structural modification of the unit cell under pressure with complete accumulation of all hydrogen atoms in these planes. As a result, the electronic properties of the system become quasi-two-dimensional. We have also analyzed the collective synphase and antiphase vibrations of hydrogen atoms in these planes, leading to the occurrence of two high-energy peaks in the phonon density of states.

  1. Durable Cu composite catalyst for hydrogen production by high temperature methanol steam reforming

    NASA Astrophysics Data System (ADS)

    Matsumura, Yasuyuki

    2014-12-01

    Durable catalysts are necessitated for the high temperature methanol steam reforming in compact hydrogen processors. The high durability at 400 °C can be obtained with a composite Cu catalyst where a small amount of Cu-ZnO-ZrO2-Y2O3-In2O3 is coprecipitated on a zirconia support. The lifetime of the composite catalyst containing 3 wt.% Cu is estimated to be as long as 53 × 102 h at 400 °C to produce the full conversion at a contact time of 250 g h m-3. The deactivation rate empirically relates to the cube of the activity. The gradual deactivation is caused by the gradual reduction of the Cu surface amount and also by the reduction of the surface activity which is believed to decrease with an increase in the Cu particle size. The interaction between the thin layer of the coprecipitate and the support surface probably suppresses the aggregation of the coprecipitate leading to Cu sintering.

  2. Effect of high temperature hydrogen exposure on the strength and microstructure of mullite

    NASA Technical Reports Server (NTRS)

    Herbell, Thomas P.; Hull, David; Hallum, Garry M.

    1990-01-01

    The corrosion of near stoichiometric mullite (3Al2O3-2SiO2) by pure dry hydrogen gas was studied at 1050 and 1250 C for times up to 500 hr. The hydrogen preferentially attacked the grain boundaries of the mullite where an aluminosilicate glass was present. Corrosion of the mullite grains was observed after 125 hr at 1250 C. The hydrogen reaction removed SiO2 from the glassy grain boundaries and the mullite grains resulting in a porous alumina rich surface. At 1250 C the strength increased after short exposure times (at least up to 125 hr) and decreased by 53 percent after 500 hr. At 1050 C, all exposure times (25 to 500 hr) decreased the strength. At 500 hr room temperature strength of mullite exposed to 1050 C was reduced by 22 percent. The strength reduction after short exposure times at 1050 C is attributed to crystallization of the grain boundary glass phase.

  3. Prediction of a superionic phase of hydrogen fluoride (HF) at high temperature and pressure

    NASA Astrophysics Data System (ADS)

    Fried, Laurence; Goldman, Nir

    2006-03-01

    We report first principles simulations of hydrogen fluoride. Ab initio molecular dynamics simulations of HF were conducted at densities of 1.8 -- 4.0 g/cc along the 900 K isotherm. At experimentally observable conditions, we find a transition to a superionic phase, in which the fluorine ions exhibit a stable lattice and the hydrogen ions exhibit rapid diffusion. This phase is similar to the recently reported superionic phase in water, in that there is a symmetrization of the hydrogen bond, and we observe a transient partially covalent network at pressures greater than 66 GPa. In addition, we describe a mechanism for hydrogen diffusion through the fluorine sub- lattice. Our results provide evidence that superionic solids are prevalent in solids that manifest low temperature symmetric hydrogen bonding. The pressures needed to induce superionic diffusion in HF are significantly lower than what is required for other known superionic hydrides, and thus will permit much more extensive experimental studies of this exotic phase.

  4. Increased Stabilized Performance Of Amorphous Silicon Based Devices Produced By Highly Hydrogen Diluted Lower Temperature Plasma Deposition.

    DOEpatents

    Li, Yaun-Min; Bennett, Murray S.; Yang, Liyou

    1997-07-08

    High quality, stable photovoltaic and electronic amorphous silicon devices which effectively resist light-induced degradation and current-induced degradation, are produced by a special plasma deposition process. Powerful, efficient single and multi-junction solar cells with high open circuit voltages and fill factors and with wider bandgaps, can be economically fabricated by the special plasma deposition process. The preferred process includes relatively low temperature, high pressure, glow discharge of silane in the presence of a high concentration of hydrogen gas.

  5. Increasing Stabilized Performance Of Amorphous Silicon Based Devices Produced By Highly Hydrogen Diluted Lower Temperature Plasma Deposition.

    DOEpatents

    Li, Yaun-Min; Bennett, Murray S.; Yang, Liyou

    1999-08-24

    High quality, stable photovoltaic and electronic amorphous silicon devices which effectively resist light-induced degradation and current-induced degradation, are produced by a special plasma deposition process. Powerful, efficient single and multi-junction solar cells with high open circuit voltages and fill factors and with wider bandgaps, can be economically fabricated by the special plasma deposition process. The preferred process includes relatively low temperature, high pressure, glow discharge of silane in the presence of a high concentration of hydrogen gas.

  6. Parametric Evaluation of Large-Scale High-Temperature Electrolysis Hydrogen Production Using Different Advanced Nuclear Reactor Heat Sources

    SciTech Connect

    Edwin A. Harvego; Michael G. McKellar; James E. O'Brien; J. Stephen Herring

    2009-09-01

    High Temperature Electrolysis (HTE), when coupled to an advanced nuclear reactor capable of operating at reactor outlet temperatures of 800 °C to 950 °C, has the potential to efficiently produce the large quantities of hydrogen needed to meet future energy and transportation needs. To evaluate the potential benefits of nuclear-driven hydrogen production, the UniSim process analysis software was used to evaluate different reactor concepts coupled to a reference HTE process design concept. The reference HTE concept included an Intermediate Heat Exchanger and intermediate helium loop to separate the reactor primary system from the HTE process loops and additional heat exchangers to transfer reactor heat from the intermediate loop to the HTE process loops. The two process loops consisted of the water/steam loop feeding the cathode side of a HTE electrolysis stack, and the sweep gas loop used to remove oxygen from the anode side. The UniSim model of the process loops included pumps to circulate the working fluids and heat exchangers to recover heat from the oxygen and hydrogen product streams to improve the overall hydrogen production efficiencies. The reference HTE process loop model was coupled to separate UniSim models developed for three different advanced reactor concepts (a high-temperature helium cooled reactor concept and two different supercritical CO2 reactor concepts). Sensitivity studies were then performed to evaluate the affect of reactor outlet temperature on the power cycle efficiency and overall hydrogen production efficiency for each of the reactor power cycles. The results of these sensitivity studies showed that overall power cycle and hydrogen production efficiencies increased with reactor outlet temperature, but the power cycles producing the highest efficiencies varied depending on the temperature range considered.

  7. High methane formation during the temperature-programmed decomposition in flowing hydrogen of supported mononuclear and polynuclear carbonyl complexes

    SciTech Connect

    Hucul, D.A.; Brenner, A.

    1981-01-14

    This paper presents the first detailed study of the temperature-programmed decomposition (TPDE) in flowing hydrogen of every element which forms a stable carbonyl. The investigation shows that these systems have an unexpectedly high propensity to form methane. The parameters affecting the yield of methane are described and this stoichiometric reaction is compared to catalytic methanation. (AT)

  8. Development of High Temperature SiC Based Hydrogen/Hydrocarbon Sensors with Bond Pads for Packaging

    NASA Technical Reports Server (NTRS)

    Xu, Jennifer C.; Hunter, Gary W.; Chen, Liangyu; Biagi-Labiosa, Azlin M.; Ward, Benjamin J.; Lukco, Dorothy; Gonzalez, Jose M., III; Lampard, Peter S.; Artale, Michael A.; Hampton, Christopher L.

    2011-01-01

    This paper describes efforts towards the transition of existing high temperature hydrogen and hydrocarbon Schottky diode sensor elements to packaged sensor structures that can be integrated into a testing system. Sensor modifications and the technical challenges involved are discussed. Testing of the sensors at 500 C or above is also presented along with plans for future development.

  9. Composition for use in high-temperature hydrogen-fluorine environments and method for making the composition

    DOEpatents

    Kovach, L.; Holcombe, C.E.

    1980-08-22

    The present invention relates to a composition particularly suitable for use as structural components subject to high-temperature environments containing gaseous hydrogen and fluorine. The composition of the present invention consists essentially of lanthanum hexaboride-molybdenum diboride with dispersed silicon. The composition is formed by hot pressing a powder mixture of lanthanum hexaboride as the major constituent and molybdenum disilicide. This composition exhibits substantial resistance to thermal shock and corrosion in environments containing hydrogen and fluorine gases at material surface temperatures up to about 1850/sup 0/K. Upon exposure of the hot-pressed composition to high-temperature environments containing fluorine gases, a highly protective layer of lanthanum trifluoride containing dispersed molybdenum is formed on exposed surfaces of the composition.

  10. Composition for use in high-temperature hydrogen-fluorine environments and method for making the composition

    DOEpatents

    Kovach, Louis; Holcombe, Cressie E.

    1982-01-01

    The present invention relates to a composition particularly suitable for as structural components subject to high-temperature environments containing gaseous hydrogen and fluorine. The composition of the present invention consists essentially of lanthanum hexaboride-molybdenum diboride with dispersed silicon. The composition is formed by hot pressing a powder mixture of lanthanum hexaboride as the major constituent and molybdenum disilicide. This composition exhibits substantial resistance to thermal shock and corrosion in environments containing hydrogen and fluorine gases at material surface temperatures up to about 1850.degree. K. Upon exposure of the hot-pressed composition to high-temperature environments containing fluorine gases, a highly protective layer of lanthanum trifluoride containing dispersed molybdenum is formed on exposed surfaces of the composition.

  11. Influence of oxide layer morphology on hydrogen concentration in tin and niobium containing zirconium alloys after high temperature steam oxidation

    NASA Astrophysics Data System (ADS)

    Große, Mirco; Lehmann, Eberhard; Steinbrück, Martin; Kühne, Guido; Stuckert, Juri

    2009-03-01

    The influence of the oxide layer morphology on the hydrogen uptake during steam oxidation of (Zr,Sn) and Zr-Nb nuclear fuel rod cladding alloys was investigated in isothermal separate-effect tests and large-scale fuel rod bundle simulation experiments. From both it can be concluded that the concentration of hydrogen in the remaining metal strongly depends on the existence of tangential cracks in the oxide layers formed by the tetragonal - monoclinic phase transition in the oxide, known as breakaway effect. In these cracks hydrogen is strongly enriched. It results in very local high hydrogen partial pressure at the oxide/metal interface and in an increase of the hydrogen concentration in the metal at local regions where such cracks in the oxide layer exist. Due to this effect the hydrogen uptake of the remaining zirconium alloy does not depend monotonically on temperature. Differences between (Zr,Sn) and Zr-Nb alloys are caused by differences in the hydrogen production due to different oxidation kinetics and in the crack forming phase transformation in the oxides as well as in the mechanical stability of the oxides.

  12. Hydrogen Selective Inorganic membranes for Gas Separations under High Pressure Intermediate Temperature Hydrocarbonic Envrionment

    SciTech Connect

    Rich Ciora; Paul KT Liu

    2012-06-27

    In this project, we have successfully developed a full scale commercially ready carbon molecular sieve (CMS) based membrane for applications in H{sub 2} recovery from refinery waste and other aggressive gas streams. Field tests at a refinery pilot plant and a coal gasification facility have successfully demonstrated its ability to recovery hydrogen from hydrotreating and raw syngas respectively. High purity H{sub 2} and excellent stability of the membrane permeance and selectivity were obtained in testing conducted over >500 hours at each site. The results from these field tests as well as laboratory testing conclude that the membranes can be operated at high pressures (up to 1,000 psig) and temperatures (up to 300 C) in presence of aggressive contaminants, such as sulfur and nitrogen containing species (H{sub 2}S, CO{sub 2}, NH{sub 3}, etc), condensable hydrocarbons, tar-like species, heavy metals, etc. with no observable effect on membrane performance. By comparison, similar operating conditions and/or environments would rapidly destroy competing membranes, such as polymeric, palladium, zeolitic, etc. Significant cost savings can be achieved through recovering H{sub 2} from refinery waste gas using this newly developed CMS membrane. Annual savings of $2 to 4MM/year (per 20,000 scfd of waste gas) can be realized by recovering the H{sub 2} for reuse (versus fuel). Projecting these values over the entire US market, potential H{sub 2} savings from refinery waste gases on the order of 750 to 1,000MM scfd and $750 to $1,000MM per year are possible. In addition to the cost savings, potential energy savings are projected to be ca. 150 to 220 tBTU/yr and CO{sub 2} gas emission reductions are projected to be ca. 5,000 to 6,500MMtons/year. The full scale membrane bundle developed as part of this project, i.e., 85 x 30 inch ceramic membrane tubes packaged into a full ceramic potting, is an important accomplishment. No comparable commercial scale product exists in the

  13. Influence of gaseous hydrogen on the mechanical properties of high temperature alloys

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Tensile tests of six nickel-base and one cobalt-base alloy were conducted in 34.5 MN/sq m helium and hydrogen environments at temperatures from 297 K to 1,088 K. Mechanical properties tests of the nickel-base alloy MAR M-246 (Hf modified), in two cast conditions, were conducted in gaseous environments at temperatures from 297 K to 1,144 K and pressures from one atmosphere to 34.5 MN/sq m. The objective of this program was to obtain the mechanical properties of the various alloys proposed for use in space propulsion systems in a pure hydrogen environment at different temperatures and to compare with the mechanical properties in helium at the same conditions. All testing was conducted on solid specimens exposed to external gaseous pressure. Smooth and notched tensile properties were determined using ASTM tensile testing techniques, and creep-rupture life was determined using ASTM creep-rupture techniques. Low-cycle fatigue life was established by constant total strain and constant stress testing using smooth specimens and a closed-loop test machine.

  14. The corrosion behavior of Alloy 52 weld metal in cyclic hydrogenated and oxygenated water chemistry in high temperature aqueous environment

    NASA Astrophysics Data System (ADS)

    Xu, Jian; Shoji, Tetsuo

    2015-06-01

    The corrosion behavior of Alloy 52 weld metal in cyclic hydrogenated and oxygenated water chemistry in high temperature water is studied by in situ monitoring corrosion potential (Ecorr), contact electric resistance (CER) and electrochemical impedance measurements (EIS), and ex situ scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. The Ecorr and film resistance show large change when the environment is changed from hydrogenated water to oxygenated water and changeable with changing environment while the morphology and composition only show obvious distinction in the first cycle. The main factor controlling the electric/electrochemical properties of the oxide film is Ecorr.

  15. Development Program of IS Process Pilot Test Plant for Hydrogen Production With High-Temperature Gas-Cooled Reactor

    SciTech Connect

    Jin Iwatsuki; Atsuhiko Terada; Hiroyuki Noguchi; Yoshiyuki Imai; Masanori Ijichi; Akihiro Kanagawa; Hiroyuki Ota; Shinji Kubo; Kaoru Onuki; Ryutaro Hino

    2006-07-01

    At the present time, we are alarmed by depletion of fossil energy and effects on global environment such as acid rain and global warming, because our lives depend still heavily on fossil energy. So, it is universally recognized that hydrogen is one of the best energy media and its demand will be increased greatly in the near future. In Japan, the Basic Plan for Energy Supply and Demand based on the Basic Law on Energy Policy Making was decided upon by the Cabinet on 6 October, 2003. In the plan, efforts for hydrogen energy utilization were expressed as follows; hydrogen is a clean energy carrier without carbon dioxide (CO{sub 2}) emission, and commercialization of hydrogen production system using nuclear, solar and biomass, not fossil fuels, is desired. However, it is necessary to develop suitable technology to produce hydrogen without CO{sub 2} emission from a view point of global environmental protection, since little hydrogen exists naturally. Hydrogen production from water using nuclear energy, especially the high-temperature gas-cooled reactor (HTGR), is one of the most attractive solutions for the environmental issue, because HTGR hydrogen production by water splitting methods such as a thermochemical iodine-sulfur (IS) process has a high possibility to produce hydrogen effectively and economically. The Japan Atomic Energy Agency (JAEA) has been conducting the HTTR (High-Temperature Engineering Test Reactor) project from the view to establishing technology base on HTGR and also on the IS process. In the IS process, raw material, water, is to be reacted with iodine (I{sub 2}) and sulfur dioxide (SO{sub 2}) to produce hydrogen iodide (HI) and sulfuric acid (H{sub 2}SO{sub 4}), the so-called Bunsen reaction, which are then decomposed endo-thermically to produce hydrogen (H{sub 2}) and oxygen (O{sub 2}), respectively. Iodine and sulfur dioxide produced in the decomposition reactions can be used again as the reactants in the Bunsen reaction. In JAEA, continuous

  16. System Evaluation and Life-Cycle Cost Analysis of a Commercial-Scale High-Temperature Electrolysis Hydrogen Production Plant

    SciTech Connect

    Edwin A. Harvego; James E. O'Brien; Michael G. McKellar

    2012-11-01

    Results of a system evaluation and lifecycle cost analysis are presented for a commercial-scale high-temperature electrolysis (HTE) central hydrogen production plant. The plant design relies on grid electricity to power the electrolysis process and system components, and industrial natural gas to provide process heat. The HYSYS process analysis software was used to evaluate the reference central plant design capable of producing 50,000 kg/day of hydrogen. The HYSYS software performs mass and energy balances across all components to allow optimization of the design using a detailed process flow sheet and realistic operating conditions specified by the analyst. The lifecycle cost analysis was performed using the H2A analysis methodology developed by the Department of Energy (DOE) Hydrogen Program. This methodology utilizes Microsoft Excel spreadsheet analysis tools that require detailed plant performance information (obtained from HYSYS), along with financial and cost information to calculate lifecycle costs. The results of the lifecycle analyses indicate that for a 10% internal rate of return, a large central commercial-scale hydrogen production plant can produce 50,000 kg/day of hydrogen at an average cost of $2.68/kg. When the cost of carbon sequestration is taken into account, the average cost of hydrogen production increases by $0.40/kg to $3.08/kg.

  17. Palladium/Copper Alloy Composite Membranes for High Temperature Hydrogen Separation

    SciTech Connect

    J. Douglas Way; Paul M. Thoen

    2006-08-31

    This report summarizes progress made during the a three year University Coal Research grant (DEFG26-03NT41792) at the Colorado School of Mines. The period of performance was September 1, 2003 through August of 2006. We made excellent progress toward our goal of contributing to the development of high productivity, sulfur tolerant composite metal membranes for hydrogen production and membrane reactors. Composite Pd and Pd alloy metal membranes with thin metal films (1-7 {micro}m) were prepared on porous stainless steel and ceramic supports that meet or exceed the DOE 2010 and 2015 pure hydrogen flux targets at differential pressure of only 20 psi. For example, a 2 {micro}m pure Pd membrane on a Pall AccuSep{reg_sign} substrate achieved an ideal H{sub 2}/N{sub 2} separation factor of over 6000, with a pure hydrogen flux of 210 SCFH/ft{sup 2} at only 20 psig feed pressure. Similar performance was achieved with a Pd{sub 80}Au{sub 20} composite membrane on a similar stainless steel substrate. Extrapolating the pure hydrogen flux of this PdAu membrane to the DOE Fossil Energy target conditions of 150 psia feed pressure and 50 psia permeate pressure gives a value of 508 SCFH/ft{sup 2}, exceeding the 2015 target. At these thicknesses, it is the support cost that will dominate the cost of a large scale module. In a direct comparison of FCC phase PdCu and PdAu alloys on identical supports, we showed that a Pd{sub 85}Au{sub 15} (mass %) alloy membrane is not inhibited by CO, CO{sub 2}, or steam present in a water-gas shift feed mixture at 400 C, has better resistance to sulfur than a Pd{sub 94}Cu{sub 6} membrane, and has over twice the hydrogen permeance.

  18. Structural changes of filled ice Ic hydrogen hydrate under low temperatures and high pressures from 5 to 50 GPa

    NASA Astrophysics Data System (ADS)

    Hirai, Hisako; Kagawa, Shingo; Tanaka, Takehiko; Matsuoka, Takahiro; Yagi, Takehiko; Ohishi, Yasuo; Nakano, Satoshi; Yamamoto, Yoshitaka; Irifune, Tetsuo

    2012-08-01

    Low-temperature and high-pressure experiments were performed on the filled ice Ic structure of hydrogen hydrate at previously unexplored conditions of 5-50 GPa and 30-300 K using diamond anvil cells and a helium-refrigeration cryostat. In situ x-ray diffractometry revealed that the cubic filled ice Ic structure transformed to tetragonal at low temperatures and high pressures; the axis ratio of the tetragonal phase changed depending on the pressure and temperature. These results were consistent with theoretical predictions performed via first principle calculations. The tetragonal phase was determined to be stable above 20 GPa at 300 K, above 15 GPa at 200 K, and above 10 GPa at 100 K. Further changes in the lattice parameters were observed from about 45-50 GPa throughout the temperature region examined, which suggests the transformation to another high-pressure phase above 50 GPa. In our previous x-ray study that was performed up to 80 GPa at room temperature, a similar transformation was observed above 50 GPa. In this study, the observed change in the lattice parameters corresponds to the beginning of that transformation. The reasons for the transformation to the tetragonal structure are briefly discussed: the tetragonal structure might be induced due to changes in the vibrational or rotational modes of the hydrogen molecules under low temperature and high pressure.

  19. Structural changes of filled ice Ic hydrogen hydrate under low temperatures and high pressures from 5 to 50 GPa.

    PubMed

    Hirai, Hisako; Kagawa, Shingo; Tanaka, Takehiko; Matsuoka, Takahiro; Yagi, Takehiko; Ohishi, Yasuo; Nakano, Satoshi; Yamamoto, Yoshitaka; Irifune, Tetsuo

    2012-08-21

    Low-temperature and high-pressure experiments were performed on the filled ice Ic structure of hydrogen hydrate at previously unexplored conditions of 5-50 GPa and 30-300 K using diamond anvil cells and a helium-refrigeration cryostat. In situ x-ray diffractometry revealed that the cubic filled ice Ic structure transformed to tetragonal at low temperatures and high pressures; the axis ratio of the tetragonal phase changed depending on the pressure and temperature. These results were consistent with theoretical predictions performed via first principle calculations. The tetragonal phase was determined to be stable above 20 GPa at 300 K, above 15 GPa at 200 K, and above 10 GPa at 100 K. Further changes in the lattice parameters were observed from about 45-50 GPa throughout the temperature region examined, which suggests the transformation to another high-pressure phase above 50 GPa. In our previous x-ray study that was performed up to 80 GPa at room temperature, a similar transformation was observed above 50 GPa. In this study, the observed change in the lattice parameters corresponds to the beginning of that transformation. The reasons for the transformation to the tetragonal structure are briefly discussed: the tetragonal structure might be induced due to changes in the vibrational or rotational modes of the hydrogen molecules under low temperature and high pressure. PMID:22920129

  20. 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.

  1. Oxidation of Inconel 625 superalloy upon treatment with oxygen or hydrogen plasma at high temperature

    NASA Astrophysics Data System (ADS)

    Vesel, Alenka; Drenik, Aleksander; Elersic, Kristina; Mozetic, Miran; Kovac, Janez; Gyergyek, Tomaz; Stockel, Jan; Varju, Jozef; Panek, Radomir; Balat-Pichelin, Marianne

    2014-06-01

    Initial stages of Inconel 625 superalloy (Ni60Cr30Mo10Ni4Nb1) oxidation upon short treatment with gaseous plasma at different temperatures up to about 1600 K were studied. Samples were treated for different periods up to a minute by oxygen or hydrogen plasma created with a microwave discharge in the standing-wave mode at a pressure of 40 Pa and a power 500 W. Simultaneous heating of the samples was realized by focusing concentrated solar radiation from a 5 kW solar furnace directly onto the samples. The morphological changes upon treatment were monitored using scanning electron microscopy, compositional depth profiling was performed using Auger electron spectroscopy, while structural changes were determined by X-ray diffraction. The treatment in oxygen plasma caused formation of metal oxide clusters of three dimensional crystallites initially rich in nickel oxide with the increasing chromium oxide content as the temperature was increasing. At about 1100 K iron and niobium oxides prevailed on the surface causing a drop of the material emissivity at 5 μm. Simultaneously the NiCr2O4 compound started growing at the interface between the oxide film and bulk alloy and the compound persisted up to temperatures close to the Inconel melting point. Intensive migration of minority alloying elements such as Fe and Ti was observed at 1600 K forming mixed surface oxides of sub-micrometer dimensions. The treatment in hydrogen plasma with small admixture of water vapor did not cause much modification unless the temperature was close to the melting point. At such conditions aluminum segregated on the surface and formed well-defined Al2O3 crystals.

  2. Stabilities of filled ice II structure of hydrogen and helium hydrates at low temperatures and high pressures

    NASA Astrophysics Data System (ADS)

    Hirai, H.; Umeda, A.; Fujii, T.; Machida, S.; Shinozaki, A.; Kawamura, T.; Yamamoto, Y.; Yagi, T.

    2011-12-01

    Hydrogen hydrate is expected to be a hydrogen storage material, because it can contain relatively high hydrogen and its synthetic condition is mild comparable to industrial production. Three phases of hydrogen hydrate have been known so for. One is a clathrate hydrate sII [1], and others are filled ice II structure and filled ice Ic structure [2]. The ratio of water to hydrogen molecules for these phases are1:3, 1:6, 1:1, respectively. The clathrate sII containing only hydrogen molecules is stable only in a lower temperature region. At room temperature, above about 0.8 GPa filled ice II and above 2.5 GPa filled ice Ic are formed. The latter one survives at least up to 90 GPa [3]. However, investigations in low temperature and high pressure region have been limited. In this study, low temperature and high pressure experiments were performed by using diamond anvil cells and a helium-refrigeration cryostat in a region of 0.2 to 4.5 GPa and 130 to 300 K. X-ray diffractometry (XRD) showed a series of phase change from sII to filled ice Ic via filled ice II. For example, at 220K, sII transformed to filled ice II at approximately 0.7 GPa and further transformed to filled ice Ic structure at about 2.0 GPa. The present results experimentally confirmed the previously predicted phase boundaries. For filled ice II structure, Raman spectroscopy revealed that pressure dependency of vibration mode of guest hydrogen molecules and OH stretching mode of host water molecules changed at approximately 2.5 GPa. The XRD also showed change in axial ratio at the same pressure. These result suggested that state of filled ice II structure changed at about 2.5 GPa. Helium hydrate is known to form filled ice II structure [4], but high pressure study has not been yet fully performed. Similar experiments were carried out in a region of 0.2 to 5.0 GPa and 200 to 300 K. The results showed that the filled ice II structure did not transformed to filled ice Ic structure, but decomposed into helium

  3. Hydrogen Storage in Nano-Phase Diamond at High Temperature and Its Release

    SciTech Connect

    Tushar K Ghosh

    2008-10-13

    The objectives of this proposed research were: 91) Separation and storage of hydrogen on nanophase diamonds. It is expected that the produced hydrogen, which will be in a mixture, can be directed to a nanophase diamond system directly, which will not only store the hydrogen, but also separate it from the gas mixture, and (2) release of the stored hydrogen from the nanophase diamond.

  4. Studies of the use of heat from high temperature nuclear sources for hydrogen production processes

    NASA Technical Reports Server (NTRS)

    Farbman, G. H.

    1976-01-01

    Future uses of hydrogen and hydrogen production processes that can meet the demand for hydrogen in the coming decades were considered. To do this, a projection was made of the market for hydrogen through the year 2000. Four hydrogen production processes were selected, from among water electrolysis, fossil based and thermochemical water decomposition systems, and evaluated, using a consistent set of ground rules, in terms of relative performance, economics, resource requirements, and technology status.

  5. Theory of radical-induced ignition of counterflowing hydrogen versus oxygen at high temperatures

    SciTech Connect

    Helenbrook, B.T.; Im, H.G.; Law, C.K.

    1998-01-01

    Ignition of hydrogen and oxygen in counterflow was studied using asymptotic methods for temperatures above that of crossover. Starting with seven elementary reaction steps, a reduced mechanism was derived using chemical steady-state approximations for the O and OH radicals. An algebraic ignition criterion was derived using this mechanism which predicts the ignition state as a function of the parameters defining the system. This criterion successfully explains the behavior analogous to the first and second explosion limits observed in homogeneous hydrogen-oxygen mixtures. A bifurcation analysis was then performed to clarify the ignition behavior. This analysis demonstrated that an ignition turning point can occur solely through the interaction of radical species with no contribution from heat release. The source of this turning was found to be the reaction H + HO{sub 2} {yields} 20H, confirming results from numerical calculations. Finally, the regimes in which abrupt or monotonic transition to an ignited state were recalculated including the effect of this reaction.

  6. High Temperature Separation of Carbon Dioxide/Hydrogen Mixtures Using Facilitated Supported Ionic Liquid Membranes

    SciTech Connect

    Myers, C.R.; Pennline, H.W.; Luebke, D.R.; Ilconich, J.B.; Dixon, J.K.; Maginn, E.J.; Brennecke, J.F.

    2008-09-01

    Efficiently separating CO2 from H2 is one of the key steps in the environmentally responsible uses of fossil fuel for energy production. A wide variety of resources, including petroleum coke, coal, and even biomass, can be gasified to produce syngas (a mixture of COand H2). This gas stream can be further reacted with water to produce CO2 and more H2. Once separated, the CO2 can be stored in a variety of geological formations or sequestered by other means. The H2 can be combusted to operate a turbine, producing electricity, or used to power hydrogen fuel cells. In both cases, onlywater is produced as waste. An amine functionalized ionic liquid encapsulated in a supported ionic liquid membrane (SILM) can separate CO2 from H2 with a higher permeability and selectivity than any known membrane system. This separation is accomplished at elevated temperatures using facilitated transport supported ionic liquid membranes.

  7. Life cycle assessment of hydrogen production from S-I thermochemical process coupled to a high temperature gas reactor

    SciTech Connect

    Giraldi, M. R.; Francois, J. L.; Castro-Uriegas, D.

    2012-07-01

    The purpose of this paper is to quantify the greenhouse gas (GHG) emissions associated to the hydrogen produced by the sulfur-iodine thermochemical process, coupled to a high temperature nuclear reactor, and to compare the results with other life cycle analysis (LCA) studies on hydrogen production technologies, both conventional and emerging. The LCA tool was used to quantify the impacts associated with climate change. The product system was defined by the following steps: (i) extraction and manufacturing of raw materials (upstream flows), (U) external energy supplied to the system, (iii) nuclear power plant, and (iv) hydrogen production plant. Particular attention was focused to those processes where there was limited information from literature about inventory data, as the TRISO fuel manufacture, and the production of iodine. The results show that the electric power, supplied to the hydrogen plant, is a sensitive parameter for GHG emissions. When the nuclear power plant supplied the electrical power, low GHG emissions were obtained. These results improve those reported by conventional hydrogen production methods, such as steam reforming. (authors)

  8. Ternary MgTiX-alloys: a promising route towards low-temperature, high-capacity, hydrogen-storage materials.

    PubMed

    Vermeulen, Paul; van Thiel, Emile F M J; Notten, Peter H L

    2007-01-01

    In the search for hydrogen-storage materials with a high gravimetric capacity, Mg(y)Ti((1-y)) alloys, which exhibit excellent kinetic properties, form the basis for more advanced compounds. The plateau pressure of the Mg--Ti--H system is very low (approximately 10(-6) bar at room temperature). A way to increase this pressure is by destabilizing the metal hydride. The foremost effect of incorporating an additional element in the binary Mg--Ti system is, therefore, to decrease the stability of the metal hydride. A model to calculate the effect on the thermodynamic stability of alloying metals was developed by Miedema and co-workers. Adopting this model offers the possibility to select promising elements beforehand. Thin films consisting of Mg and Ti with Al or Si were prepared by means of e-beam deposition. The electrochemical galvanostatic intermittent titration technique was used to obtain pressure-composition isotherms for these ternary materials and these isotherms reveal a reversible hydrogen-storage capacity of more than 6 wt. %. In line with the calculations, substitution of Mg and Ti by Al or Si indeed shifts the plateau pressure of a significant part of the isotherms to higher pressures, while remaining at room temperature. It has been proven that, by controlling the chemistry of the metal alloy, the thermodynamic properties of Mg-based hydrides can be regulated over a wide range. Hence, the possibility to increase the partial hydrogen pressure, while maintaining a high gravimetric capacity creates promising opportunities in the field of hydrogen-storage materials, which are essential for the future of the hydrogen economy. PMID:17879246

  9. Low-temperature embrittlement of Ti-6Al-4V and Inconel-718 by high pressure hydrogen

    NASA Technical Reports Server (NTRS)

    Chandler, W. T.; Walter, R. J.

    1970-01-01

    Notched specimens of titanium alloy and Inconel-718 exhibit little reduction of notch strength at certain low temperatures under 2000 lb/sq in. hydrogen, unnotched specimens are not embrittled at these temperatures. The degree of Inconel-718 embrittlement is lower than earlier observations under 1000 lb/sq in. hydrogen.

  10. High speed hydrogen/graphite interaction

    NASA Technical Reports Server (NTRS)

    Kelly, A. J.; Hamman, R.; Sharma, O. P.; Harrje, D. T.

    1974-01-01

    Various aspects of a research program on high speed hydrogen/graphite interaction are presented. Major areas discussed are: (1) theoretical predictions of hydrogen/graphite erosion rates; (2) high temperature, nonequilibrium hydrogen flow in a nozzle; and (3) molecular beam studies of hydrogen/graphite erosion.

  11. Diffusion of hydrogen through platinum membranes at high pressures and temperatures

    NASA Technical Reports Server (NTRS)

    Chou, I.-M.; Eugster, H. P.; Berens, P.; Weare, J. H.

    1978-01-01

    The diffusion of hydrogen through platinum membranes has been measured at 450, 500, 550 and 600 C at 2000 bar pressure, using the hydrogen sensor technique. Ag + AgCl + 3M HCl was the starting solution inside the platinum tube. Hydrogen diffuses out of the platinum tube into a system containing Fe2O3 + Fe3O4 + H2O; that is, a solution with a fixed hydrogen fugacity. After quench, the drop in hydrogen fugacity inside the platinum tube was calculated from measurements of pH and chloride molality. The hydrogen fugacity is initially roughly proportional to the square root of time. Diffusion constants were calculated from these data by numerical integration.

  12. Properties of materials in high pressure hydrogen at room and elevated temperatures

    NASA Technical Reports Server (NTRS)

    Harris, J. A., Jr.

    1972-01-01

    Experimental efforts in this program for this period. Mechanical property tests of wrought and cast nickel-base alloys and one wrought cobalt-base alloy were conducted in 34.5 MN/sq m (5000-psig) helium and hydrogen or hydrogen mixtures. Comparison of test results was made to determine degradation of properties due to the hydrogen environments. All testing was conducted on solid specimens exposed to external gaseous pressure. Specific mechanical properties determined and the testing methods used are summarized.

  13. Solubility of, and hydrogen ion adsorption on, some metal oxides in aqueous solutions to high temperatures

    SciTech Connect

    Palmer, D.A.; Benezeth, P.; Wesolowski, D.J.; Anovitz, L.M.; Machesky, M.L.; Hayashi, Ken-ichiro; Hyde, K.E.

    1997-08-01

    Solubility of boehmite (AlOOH), ferrous hydroxide (Fe(OH)2)/magnetite (Fe3O4), zincite (ZnO), and brucite (Mg(OH)2) were measured over a range of temperatures (AlOOH, 100-290 C; Fe(OH)2/Fe3O4, 100-250 C; ZnO, 50-290 C; Mg(OH)2, 60-200 C) using in situ pH measurements. A hydrogen-electrode concentration cell was used; the pH range depended on the oxide. The solubility results for boehmite mainly demonstrate the method viability, while those for zincite are mainly restricted to mildly acidic to neutral pH where Zn{sup 2+} predominates in solution. The magnetite (presumably coated with Fe(OH)2) solubilities extend from pHs > 5 and, because of relevance to water/steam cycles of power plants, are compared in detail with previous studies. The same cell was used to investigate the surface adsorption-desorption thermodynamics of H ions on rutile (TiO2) and zincite to 290 C. Behavior of pH at zero-point-of-charge as function of temperature and application of the Stern-3-layer model were determined for this solid. The zincite study is still incomplete; preliminary results show trends that can be rationalized only qualitatively now with the zero- point-of-charge being apparently affected by hydration of the surface in basic solutions and specific adsorption of Na ions under the same conditions.

  14. Hydrogen Ingress in Steels During High-Temperature Oxidation in Water Vapor

    SciTech Connect

    Brady, Michael P; Fayek, Mostafa; Keiser, James R; Meyer III, Harry M; More, Karren Leslie; Anovitz, Lawrence {Larry} M; Wesolowski, David J; Cole, David R

    2011-01-01

    It is well established that hydrogen derived from water vapour can penetrate oxidizing alloys with detrimental effect. However, the complexities of tracking hydrogen in these materials have prevented the direct profiling of hydrogen ingress needed to understand these phenomena. Here we report hydrogen profiles in industrially-relevant alumina- and chromia- forming steels correlated with the local oxide-metal nano/microstructure by use of SIMS D2O tracer studies and experimental protocols to optimize D retention. The D profiles unexpectedly varied markedly among the alloys examined, which indicates mechanistic complexity but also the potential to mitigate detrimental water vapour effects by manipulation of alloy chemistry.

  15. Understanding microstructure-induced limitations of hydrogen transport in high temperature proton conductors: can nuclear microanalysis give an answer?

    NASA Astrophysics Data System (ADS)

    Berger, Pascal

    2007-03-01

    High temperature protonic conductors (HTPC) are envisioned as electrolytes for fuel cells working at intermediate temperature (400 C -- 600 C) to complement Y:ZrO2 electrolytes operating at 800 C -- 1000 C. The most mature HTPC are doped perovskites (ABO3) where tetravalent cation B is partially substituted by a trivalent one. Protons can be introduced in the lattice as point defects corresponding to hydroxyl groups on oxygen ion sites. In the temperature region of interest for technological applications, lattice vibrations allow the diffusion of protons by jumping and reorientation of O-H bonds (hoping mechanism). BaCeO3 or SrCeO3-based perovskites doped with a rare earth are the most widely studied compounds. However the proton conductance of these ceramics and their chemical stability are lower than the calculated values on single crystals and not sufficient to fulfill technological requirements. In most cases, the reasons for these discrepancies lie in uncontrolled microstructures with inter- and intra-granular defects that act as barriers for hydrogen diffusion but are preferential paths for chemical degradation by hydrolysis or carbonatation. Despite this crucial point, very few efforts are devoted to the optimization of microstructure of HTPC. Microstructure induced limitations are usually evidenced via impedance measurements which enable determination of respective contributions of bulk and grain boundaries to overall conductivity. Further information on hydrogen transport relevant for improvement of microstructure design requires local methods for hydrogen concentration measurement. Nuclear microanalysis, based on the use of MeV light ions microbeam, meets this demand. According to the chosen technique, nuclear reaction, elastic recoil or forward coincident scattering, the nuclear microprobe gives 2D-3D quantitative information on hydrogen distribution and diffusion within microstructure and enables to identify barriers and short-circuits.

  16. Ultra high vacuum high precision low background setup with temperature control for thermal desorption mass spectroscopy (TDA-MS) of hydrogen in metals.

    PubMed

    Merzlikin, Sergiy V; Borodin, S; Vogel, D; Rohwerder, M

    2015-05-01

    In this work, a newly developed UHV-based high precision low background setup for hydrogen thermal desorption analysis (TDA) of metallic samples is presented. Using an infrared heating with a low thermal capacity enables a precise control of the temperature and rapid cool down of the measurement chamber. This novel TDA-set up is superior in sensitivity to almost every standard hydrogen analyzer available commercially due to the special design of the measurement chamber, resulting in a very low hydrogen background. No effects of background drift characteristic as for carrier gas based TDA instruments were observed, ensuring linearity and reproducibility of the analysis. This setup will prove to be valuable for detailed investigations of hydrogen trapping sites in steels and other alloys. With a determined limit of detection of 5.9×10(-3)µg g(-1) hydrogen the developed instrument is able to determine extremely low hydrogen amounts even at very low hydrogen desorption rates. This work clearly demonstrates the great potential of ultra-high vacuum thermal desorption mass spectroscopy instrumentation. PMID:25702992

  17. Integrated High Temperature Coal to Hydrogen System with CO2 Separation: Semi-Annual Progress Report 1

    SciTech Connect

    Ruud, J A; Ku, A; Ramaswamy, V; Wei, W

    2005-12-21

    This is the first semi-annual progress report for the program "Integrated High Temperature Coal to Hydrogen System with CO2 Separation." The objective of the program is to develop a detailed design for a single high-temperature syngas-cleanup module to produce a pure stream of H2 from a coal-based system and to develop the new high-temperature membrane materials at the core of that design. The novel one-box process combines a shift reactor with a high-temperature CO2-selective membrane to convert CO to CO2, remove sulfur compounds, and remove CO2 in a simple, compact, fully integrated system. In the first six months of the program, a conceptual design for the one-box system was developed in Task 1 and the performance targets for the system and the membrane were evaluated. In Task 2.1 processes were developed for creating pore architectures in ceramics that are applicable to membrane structures. In Task 2.2, candidate materials were identified that have the potential for separation of CO2 and H2S at high temperatures.

  18. Effect of temperature on layer separation by plasma hydrogenation

    SciTech Connect

    Di, Z. F.; Wang, Y. Q.; Nastasi, M.; Rossi, F.; Shao, L.; Thompson, P. E.

    2008-12-22

    We have studied hydrogen diffusion in plasma hydrogenated Si/SiGe/Si heterostructure at different temperatures. At low temperature, intrinsic point defects in the molecular beam epitaxy grown Si capping layer are found to compete with the buried strain SiGe layer for hydrogen trapping. The interaction of hydrogen with point defects affects the hydrogen long-range diffusion, and restricts the amount of hydrogen available for trapping by the SiGe layer. However, hydrogen trapping by the capping layer is attenuated with increasing hydrogenation temperature allowing more hydrogen to be trapped in the strain SiGe layer with subsequent surface blister formation. A potential temperature window for plasma hydrogenation induced layer separation is identified based on the combined considerations of trap-limited diffusion at low temperature and outdiffusion of H{sub 2} molecule together with the dissociation of Si-H bonds inside of H platelet at high temperature.

  19. Effect of temperature on layer separation by plasma-hydrogenation

    SciTech Connect

    Di, Zengfeng; Michael, Nastasi A; Wang, Yongqiang

    2008-01-01

    We have studied hydrogen diffusion in plasma hydrogenated Si/SiGe/Si heterostructure at different temperatures. At low temperature, intrinsic point defects in the molecular beam epitaxy grown Si capping layer are found to compete with the buried strain SiGe layer for hydrogen trapping. The interaction of hydrogen with point defects affects the hydrogen long-range diffusion, and restricts the amount of hydrogen available for trapping by the SiGe layer. However, hydrogen trapping by the capping layer is attenuated with increasing hydrogenation temperature allowing more hydrogen to be trapped in the strain SiGe layer with subsequent surface blister formation. A potential temperature window for plasma hydrogenation induced layer separation is identified based on the combined considerations of trap-limited diffusion at low temperature and outdiffusion of H{sub 2} molecule together with the dissociation of Si-H bonds inside of H platelet at high temperature.

  20. HYBRID SULFUR CYCLE FLOWSHEETS FOR HYDROGEN PRODUCTION USING HIGH-TEMPERATURE GAS-COOLED REACTORS

    SciTech Connect

    Gorensek, M.

    2011-07-06

    Two hybrid sulfur (HyS) cycle process flowsheets intended for use with high-temperature gas-cooled reactors (HTGRs) are presented. The flowsheets were developed for the Next Generation Nuclear Plant (NGNP) program, and couple a proton exchange membrane (PEM) electrolyzer for the SO2-depolarized electrolysis step with a silicon carbide bayonet reactor for the high-temperature decomposition step. One presumes an HTGR reactor outlet temperature (ROT) of 950 C, the other 750 C. Performance was improved (over earlier flowsheets) by assuming that use of a more acid-tolerant PEM, like acid-doped poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI), instead of Nafion{reg_sign}, would allow higher anolyte acid concentrations. Lower ROT was accommodated by adding a direct contact exchange/quench column upstream from the bayonet reactor and dropping the decomposition pressure. Aspen Plus was used to develop material and energy balances. A net thermal efficiency of 44.0% to 47.6%, higher heating value basis is projected for the 950 C case, dropping to 39.9% for the 750 C case.

  1. Proton-Conducting Nanocrystalline Ceramics for High-Temperature Hydrogen Sensing

    NASA Astrophysics Data System (ADS)

    Tang, Xiling; Xu, Zhi; Trontz, Adam; Jing, Wenheng; Dong, Junhang

    2014-01-01

    The proton-conductive doped ceramic materials, including SrCe0.95Tb0.05O3-δ (SCTb), SrCe0.8Zr0.1Y0.1O3-δ (SCZY), and SrZr0.95Y0.05O3-δ (SZY), are synthesized in the forms of nanoparticles and nanocrystalline thin films on sapphire wafers and long-period grating (LPG) fibers. The H2 chemisorption and electrical conductivity of the nanocrystalline SCTb, SCZY, and SZY materials are measured at high temperature with and without the presence of CO2 gas. The resonant wavelength shifts ( Updelta λ_{{{{R,H}}_{ 2} }} ) of the SCTb, SCZY, and SZY thin-film coated LPGs in response to H2 concentration changes are studied in gas mixtures relevant to coal gasification syngas to evaluate their potential for high-temperature H2 detection. The results show that, at around 773.15 K (500 °C), SCTb has the highest H2 sensitivity but the most severe interferences from impurities such as CO2 and H2S; SZY has the best chemical resistance to impurities but the lowest H2 sensitivity; and SCZY exhibits high H2 sensitivity with reasonable chemical resistance.

  2. High temperature reactions of bibenzyl with elemental sulfur and hydrogen sulfide in the presence and absence of hydrogen and carbon monoxide

    SciTech Connect

    Hei, R.D.

    1985-01-01

    High temperature reactions were done with bibenzyl and related compounds to study C-C bond cleavage under coal liquefaction conditions. Reactions were run in 12-ml stainless steel, 3.7-ml glass and 8.0-ml aluminum autoclaves. The range of temperatures studied was 250-515/sup 0/C and that of pressure was 0-1800 psi (initial). Mechanisms for the cleavage of the aromatic-aliphatic C-C bonds (..cap alpha..-cleavage) and the aliphatic-aliphatic C-C bond (..beta..-cleavage) have been postulated. The two sets of conditions studied were: (1) those which included some form of sulfur, and those which excluded sulfur. With H/sub 2/S present, the ..beta..-cleavage to toluene was extensively promoted. The rate of this reaction was dependent on the parameters of temperature, time, H/sub 2/D concentration, and reaction surface. This ..beta..-cleavage is postulated to occur by the decomposition of the ..cap alpha..-sulfenyl bibenzyl radical. Thermal decomposition of the ..cap alpha..-sulfenyl bibenzyl radical by a known ..beta..-scission reaction yields thiobenzaldehyde and a benzyl radical which are reduced to toluene or polymerized to high molecular weight products. With molecular hydrogen present, the ..cap alpha..-cleavage to benzene and ethylbenzene is promoted. The presence of H/sub 2/S in the bibenzyl-H/sub 2/ reaction was shown to decrease the yield of ..cap alpha..-products while enhancing the conversion to 1,1-diphenylethane. The rate of ..cap alpha..-cleavage was low under essentially non-reducing conditions in this study; i.e., argon, CO-H/sub 2/O, CO-H/sub 2/O-H/sub 2/S. In this study, the mixture of carbon monoxide and water with and without hydrogen sulfide was found to be essentially non-reducing.

  3. Kinetics of the reaction between hydrogen and sulfur under high-temperature Claus furnace conditions

    SciTech Connect

    Dowling, N.I.; Hyne, J.B. ); Brown, D.M. )

    1990-12-01

    The reaction H{sub 2} + (1/2)S{sub 2} {r equilibrium}H{sub 2}S has been studied as a function of temperature and residence time over the ranges 602--1290{degrees}C and 0.03--1.5 s in the absence of a catalyst. This paper shows that the combination of H{sub 2} and elemental sulfur vapor under the high-temperature conditions typical of a Claus sulfur recovery unit proceeds via a reversible homogeneous gas-phase reaction that is first order in both H{sub 2} and sulfur concentration and follows the rate law {minus}d(H{sub 2})/dt = k{sub 1}(H{sub 2})(S{sub 2}) {minus} k{sub 2}(H{sub 2}S) with a second-order recombination rate constant k{sub 1} = 1 {minus} 1 {times} 10{sup 3} atm{sup {minus}1} s{sup {minus}1} (A{sub 1} = (4.3 {plus minus} 0.2) {times} 10{sup 6} atm{sup {minus}1} s{sup {minus}1}; {Delta}H{sub 1} = 26 {plus minus} 1 kcal/mol) and first-order decomposition rate constant k{sub 2} = 4 {times} 10{sup {minus}4} {minus} 70 s{sup {minus}1} (A{sub 2} = (3.6 {plus minus} 1) {times} 10{sup 8} s{sup {minus}1}; {Delta}H{sub 2} = 48 {plus minus} 1 kcal/mol) over the temperature range studied. These findings can be used to exploit opportunities in acid gas processing, such as effecting improved efficiencies for O{sub 2} usage in oxygen- blown Claus units and maximizing H{sub 2} content in the tail gas.

  4. High Temperature Polybenzimidazole Hollow Fiber Membranes for Hydrogen Separation and Carbon Dioxide Capture from Synthesis Gas

    DOE PAGESBeta

    Singh, Rajinder P.; Dahe, Ganpat J.; Dudeck, Kevin W.; Welch, Cynthia F.; Berchtold, Kathryn A.

    2014-12-31

    Sustainable reliance on hydrocarbon feedstocks for energy generation requires CO₂ separation technology development for energy efficient carbon capture from industrial mixed gas streams. High temperature H₂ selective glassy polymer membranes are an attractive option for energy efficient H₂/CO₂ separations in advanced power production schemes with integrated carbon capture. They enable high overall process efficiencies by providing energy efficient CO₂ separations at process relevant operating conditions and correspondingly, minimized parasitic energy losses. Polybenzimidazole (PBI)-based materials have demonstrated commercially attractive H₂/CO₂ separation characteristics and exceptional tolerance to hydrocarbon fuel derived synthesis (syngas) gas operating conditions and chemical environments. To realize a commerciallymore » attractive carbon capture technology based on these PBI materials, development of high performance, robust PBI hollow fiber membranes (HFMs) is required. In this work, we discuss outcomes of our recent efforts to demonstrate and optimize the fabrication and performance of PBI HFMs for use in pre-combustion carbon capture schemes. These efforts have resulted in PBI HFMs with commercially attractive fabrication protocols, defect minimized structures, and commercially attractive permselectivity characteristics at IGCC syngas process relevant conditions. The H₂/CO₂ separation performance of these PBI HFMs presented in this document regarding realistic process conditions is greater than that of any other polymeric system reported to-date.« less

  5. High Temperature Polybenzimidazole Hollow Fiber Membranes for Hydrogen Separation and Carbon Dioxide Capture from Synthesis Gas

    SciTech Connect

    Singh, Rajinder P.; Dahe, Ganpat J.; Dudeck, Kevin W.; Welch, Cynthia F.; Berchtold, Kathryn A.

    2014-12-31

    Sustainable reliance on hydrocarbon feedstocks for energy generation requires CO₂ separation technology development for energy efficient carbon capture from industrial mixed gas streams. High temperature H₂ selective glassy polymer membranes are an attractive option for energy efficient H₂/CO₂ separations in advanced power production schemes with integrated carbon capture. They enable high overall process efficiencies by providing energy efficient CO₂ separations at process relevant operating conditions and correspondingly, minimized parasitic energy losses. Polybenzimidazole (PBI)-based materials have demonstrated commercially attractive H₂/CO₂ separation characteristics and exceptional tolerance to hydrocarbon fuel derived synthesis (syngas) gas operating conditions and chemical environments. To realize a commercially attractive carbon capture technology based on these PBI materials, development of high performance, robust PBI hollow fiber membranes (HFMs) is required. In this work, we discuss outcomes of our recent efforts to demonstrate and optimize the fabrication and performance of PBI HFMs for use in pre-combustion carbon capture schemes. These efforts have resulted in PBI HFMs with commercially attractive fabrication protocols, defect minimized structures, and commercially attractive permselectivity characteristics at IGCC syngas process relevant conditions. The H₂/CO₂ separation performance of these PBI HFMs presented in this document regarding realistic process conditions is greater than that of any other polymeric system reported to-date.

  6. Corrosion characteristics of Ni-base superalloys in high temperature steam with and without hydrogen

    NASA Astrophysics Data System (ADS)

    Kim, Donghoon; Kim, Daejong; Lee, Ho Jung; Jang, Changheui; Yoon, Duk Joo

    2013-10-01

    The hot steam corrosion behavior of Alloy 617 and Haynes 230 were evaluated in corrosion tests performed at 900 °C in steam and steam + 20 vol.% H2 environments. Corrosion rates of Alloy 617 was faster than that of Haynes 230 at 900 °C in steam and steam + 20 vol.% H2 environments. When hydrogen was added to steam, the corrosion rate was accelerated because added hydrogen increased the concentration of Cr interstitial defects in the oxide layer. Isolated nodular MnTiO3 oxides were formed on the MnCr2O4/Cr2O3 oxide layer and sub-layer Cr2O3 was formed in steam and steam + 20 vol.% H2 for Alloy 617. On the other hand, a MnCr2O4 layer was formed on top of the Cr2O3 oxide layer for Haynes 230. The extensive sub-layer Cr2O3 formation resulted from the oxygen or hydroxide inward diffusion in such environments. When hydrogen was added, the initial surface oxide morphology was changed from a convex shape to platelets because of the accelerated diffusion of cations under the oxide layer.

  7. PALLADIUM/COPPER ALLOY COMPOSITE MEMBRANES FOR HIGH TEMPERATURE HYDROGEN SEPARATION FROM COAL-DERIVED GAS STREAMS

    SciTech Connect

    J. Douglas Way

    2001-07-31

    Recent advances have shown that Pd-Cu composite membranes are not susceptible to the mechanical, embrittlement, and poisoning problems that have prevented widespread industrial use of Pd for high temperature H2 separation. These membranes consist of a thin ({approx}1 mm) film of metal deposited on the inner surface of a porous metal or ceramic tube. Based on preliminary results, thin Pd{sub 60}Cu{sub 40} films are expected to exhibit hydrogen flux up to ten times larger than commercial polymer membranes for H2 separation, and resist poisoning by H{sub 2}S and other sulfur compounds typical of coal gas. Similar Pd-membranes have been operated at temperatures as high as 750 C. The overall objective of the proposed project is to demonstrate the feasibility of using sequential electroless plating to fabricate Pd{sub 60}Cu{sub 4}0 alloy membranes on porous supports for H{sub 2} separation. These following advantages of these membranes for processing of coal-derived gas will be demonstrated: High H{sub 2} flux; Sulfur tolerant, even at very high total sulfur levels (1000 ppm); Operation at temperatures well above 500 C; and Resistance to embrittlement and degradation by thermal cycling. The proposed research plan is designed to providing a fundamental understanding of: Factors important in membrane fabrication; Optimization of membrane structure and composition; Effect of temperature, pressure, and gas composition on H{sub 2} flux and membrane selectivity; and How this membrane technology can be integrated in coal gasification-fuel cell systems.

  8. High Temperature Oxidation of Silicon Carbide and Advanced Iron-Based Alloys in Steam-Hydrogen Environments

    SciTech Connect

    Terrani, Kurt A; Keiser, James R; Brady, Michael P; Cheng, Ting; Silva, G W Chinthaka M; Pint, Bruce A; Snead, Lance Lewis

    2012-01-01

    A side by side comparison of the oxidation behavior of zirconium alloys with SiC materials and advanced iron-based alloys is provided. Oxidation tests were conducted in steam and steam-hydrogen environments at 800-1350 C and 0.34-2MPa for durations up to 48 hours. Monolithic SiC specimens as well as SiC/SiC composites were examined during the study where the material recession mechanism appeared to be governed by silica layer volatilization at the surface for CVD SiC. A wide set of austenitic and ferritic steels were also examined where a critical Cr content (>20 wt.%) was shown to be necessary to achieve oxidation resistance at high temperatures. SiC materials and alumina-forming ferritic steels exhibited slowest oxidation kinetics; roughly two orders of magnitude lower than zirconium alloys.

  9. Semi-Coke–Supported Mixed Metal Oxides for Hydrogen Sulfide Removal at High Temperatures

    PubMed Central

    Jie, Mi; Yongyan, Zhang; Yongsheng, Zhu; Ting, Guo; Huiling, Fan

    2012-01-01

    Abstract To improve the desulfurization efficiency of sorbents at low cost, modified semi-coke was used as the substrate for mixed metal oxides (ZFM; oxides of zinc [Zn], iron [Fe], and manganese [Mn]) in hot gas desulfurization. Performance of the prepared ZFM/modified semi-coke (MS) sorbents were evaluated in a fixed-bed reactor in the temperature range 400–550°C. Results showed that the molar ratio of Mn to Zn, effect of the substrate, the calcination temperature, and the sulfidation temperature influenced the performance of the sorbents. Optimum conditions for the preparation of the ZFM/MS sorbents were molar ratio of Mn(NO3)2·6H2O, Zn(NO3)2, and Fe(NO3)3, 0.6:1:2; mass ratio of ZFM0.6 to modified semi-coke support, 1:1; and calcination temperature, 600°C. The ZFM0.6/MS sorbent thus prepared exhibited the best sorption sulfur capacity of 27.46% at 450°C. PMID:22783061

  10. Behavior of hydrogen in alpha-iron at lower temperatures

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.

    1973-01-01

    Evidence is presented that the low temperature anomalies in the hydrogen occlusive behavior of alpha iron can be explained by means of a molecular occlusion theory. This theory proposes that the stable state of the absorbed hydrogen changes from atomic at high temperatures to molecular as the temperature is lowered below a critical value. Theories proposing to explain the anomalous behavior as being due to the capture, at lower temperatures, of hydrogen in traps are shown to be unacceptable.

  11. Corrosion Behavior of 304 Stainless Steel in High Temperature, Hydrogenated Water

    SciTech Connect

    S.E. Ziemniak; M. Hanson

    2001-05-04

    The corrosion behavior of an austenitic stainless steel (UNS S30400) has been characterized in a 10,000 hour test conducted in hydrogenated, ammoniated water at 260 C. The corrosion kinetics were observed to follow a parabolic rate dependency, the parabolic rate constant being determined by chemical descaling to be 1.16 mg dm{sup -2} hr{sup -1/2}. X-ray photoelectron spectroscopy, in combination with argon ion milling and target factor analysis, was applied to provide an independent estimate of the rate constant that agreed with the gravimetric result. Based on the distribution of the three oxidized alloying constituents (Fe, Cr, Ni) with respect to depth and elemental state, it was found that: (a) corrosion occurs in a non-selective manner, and (b) the corrosion film consists of two spinel oxide layers--a ferrite-based outer layer (Ni{sub 0.2}Fe{sub 0.8})(Fe{sub 0.95}Cr{sub 0.05}){sub 2}O{sub 4} on top of a chromite-based inner layer (Ni{sub 0.2}Fe{sub 0.8})(Cr{sub 0.7}Fe{sub 0.3}){sub 2}O{sub 4}. These compositions agree closely with the solvi phases created by immiscibility in the Fe{sub 3}O{sub 4}-FeCr{sub 2}O{sub 4} binary, implying that immiscibility plays an important role in the phase separation process.

  12. Palladium/Copper Alloy Composite Membranes for High Temperature Hydrogen Separation

    SciTech Connect

    J. Douglas Way; Paul M. Thoen

    2005-08-31

    This report summarizes progress made during the second year of research funding from DOE Grant DE-FG26-03NT41792 at the Colorado School of Mines. The period of performance was September 1, 2004 through August of 2005. We have reformulated our Pd plating process to minimize the presence of carbon contamination in our membranes. This has improved durability and increased permeability. We have developed techniques for plating the outside diameter of ceramic and metal substrate tubes. This configuration has numerous advantages including a 40% increase in specific surface area, the ability to assay the alloy composition non-destructively, the ability to potentially repair defects in the plated surface, and the ability to visually examine the plated surfaces. These improvements have allowed us to already meet the 2007 DOE Fossil Energy pure H{sub 2} flux target of 100 SCFH/ft{sup 2} for a hydrogen partial pressure difference of 100 psi with several Pd-Cu alloy membranes on ceramic microfilter supports. Our highest pure H{sub 2} flux on inexpensive, porous alumina support tubes at the DOE target conditions is 215 SCFH/ft{sup 2}. Progress toward meeting the other DOE Fossil Energy performance targets is also summarized. Additionally, we have adapted our membrane fabrication procedure to apply Pd and Pd alloy films to commercially available porous stainless steel substrates. Stable performance of Pd-Cu films on stainless steel substrates was demonstrated over a three week period at 400 C. Finally, we have fabricated and tested Pd-Au alloy membranes. These membranes also exceed both the 2007 and 2010 DOE pure H{sub 2} flux targets and exhibit ideal H{sub 2}/N{sub 2} selectivities of over 1000 at partial pressure difference of 100 psi.

  13. Corrosion Behavior of NiCrFe Alloy 600 in High Temperature, Hydrogenated Water

    SciTech Connect

    SE Ziemniak; ME Hanson

    2004-11-02

    The corrosion behavior of Alloy 600 (UNS N06600) is investigated in hydrogenated water at 260 C. The corrosion kinetics are observed to be parabolic, the parabolic rate constant being determined by chemical descaling to be 0.055 mg dm{sup -2} hr{sup -1/2}. A combination of scanning and transmission electron microscopy, supplemented by energy dispersive X-ray spectroscopy and grazing incidence X-ray diffraction, are used to identify the oxide phases present (i.e., spinel) and to characterize their morphology and thickness. Two oxide layers are identified: an outer, ferrite-rich layer and an inner, chromite-rich layer. X-ray photoelectron spectroscopy with argon ion milling and target factor analysis is applied to determine spinel stoichiometry; the inner layer is (Ni{sub 0.7}Fe{sub 0.3})(Fe{sub 0.3}Cr{sub 0.7}){sub 2}O{sub 4}, while the outer layer is (Ni{sub 0.9}Fe{sub 0.1})(Fe{sub 0.85}Cr{sub 0.15}){sub 2}O{sub 4}. The distribution of trivalent iron and chromium cations in the inner and outer oxide layers is essentially the same as that found previously in stainless steel corrosion oxides, thus confirming their invariant nature as solvi in the immiscible spinel binary Fe{sub 3}O{sub 4}-FeCr{sub 2}O{sub 4} (or NiFe{sub 2}O{sub 4}-NiCr{sub 2}O{sub 4}). Although oxidation occurred non-selectively, excess quantities of nickel(II) oxide were not found. Instead, the excess nickel was accounted for as recrystallized nickel metal in the inner layer, as additional nickel ferrite in the outer layer, formed by pickup of iron ions from the aqueous phase, and by selective release to the aqueous phase.

  14. Zinc Treatment Effects on Corrosion Behavior of Alloy 600 in High Temperature, Hydrogenated Water

    SciTech Connect

    SE Ziemniak; ME Hanson

    2004-11-16

    Trace levels of soluble zinc(II) ions (30 ppb) maintained in mildly alkaline, hydrogenated water at 260 C were found to reduce the corrosion rate of Alloy 600 (UNS N06600) by about 40% relative to a non-zinc baseline test [2]. Characterizations of the corrosion oxide layer via SEM/TEM and grazing incidence X-ray diffraction confirmed the presence of a chromite-rich oxide phase and recrystallized nickel. The oxide crystals had an approximate surface density of 3500 {micro}m{sup -2} and an average size of 11 {+-} 5 nm. Application of X-ray photoelectron spectroscopy with argon ion milling, followed by target factor analyses, permitted speciated composition vs. depth profiles to be obtained. Numerical integration of the profiles revealed that: (1) alloy oxidation occurred non-selectively and (2) zinc(II) ions were incorporated into the chromite-rich spinel: (Zn{sub 0.55}Ni{sub 0.3}Fe{sub 0.15})(Fe{sub 0.25}Cr{sub 0.75}){sub 2}O{sub 4}. Spinel stoichiometry places the trivalent ion composition in the single phase oxide region, consistent with the absence of the usual outer, ferrite-rich solvus layer. By comparison with compositions of the chromite-rich spinel obtained in the non-zinc baseline test, it is hypothesized that zinc(II) ion incorporation was controlled by the equilibrium for 0.55 Zn{sup 2+}(aq) + (Ni{sub 0.7}Fe{sub 0.3})(Fe{sub 0.3}Cr{sub 0.7}){sub 2}O{sub 4}(s) {r_equilibrium} 0.40 Ni{sup 2+}(aq) + 0.15 Fe{sup 2+}(aq) + (Zn{sub 0.55}Ni{sub 0.3}Fe{sub 0.15})(Fe{sub 0.3}Cr{sub 0.7}){sub 2}O{sub 4}(s). It is estimated that only 8% of the Ni(II) ions generated during non-selective oxidation of the alloy were retained as Ni(II) in the corrosion layer; the remainder either recrystallized to Ni(0) (38%) or were released to the aqueous phase (54%).

  15. Zinc Treatment Effects on Corrosion Behavior of 304 Stainless Steel in High Temperature, Hydrogenated Water

    SciTech Connect

    S.E. Ziemniak; M. Hanson

    2001-03-20

    Trace levels of soluble zinc(II) ions (30 ppb) maintained in mildly alkaline, hydrogenated water at 260 C were found to lower the corrosion rate of austenitic stainless steel (UNS S30400) by about a factor of five, relative to a non-zinc baseline test after 10,000 hr. Characterizations of the corrosion oxide layer via grazing incidence X-ray diffraction and X-ray photoelectron spectroscopy in combination with argon ion milling and target factor analysis, confirmed the presence of two spinel oxide phases and minor amounts of recrystallized nickel. Based on the distribution of the three oxidized alloying constituents (Fe, Cr, Ni) with respect to depth and oxidation state, it was concluded that: (a) corrosion occurs in a non-selective manner, but approximately 30% of the oxidized iron is released to the water, and (b) the two spinel oxides exist as a ferrite-based outer layer (Ni{sub 0.1}Zn{sub 0.6}Fe{sub 0.3})(Fe{sub 0.95}Cr{sub 0.05}){sub 2}O{sub 4} on top of a chromite-based inner layer (Ni{sub 0.1}Zn{sub 0.2}Fe{sub 0.7})(Fe{sub 0.4}Cr{sub 0.6}){sub 2}O{sub 4}. These results suggest that immiscibility in the Fe{sub 3}O{sub 4}-ZnFe{sub 2}O{sub 4} binary may play a role in controlling the zinc content of the outer layer. On the other hand, the lower corrosion rate caused by zinc additions is believed to be a consequence of corrosion oxide film stabilization due to the substitution reaction equilibrium: z Zn{sup 2+}(aq) + FeCr{sub 2}O{sub 4}(s) {approx} z Fe{sup 2+}(aq) + (Zn{sub z}Fe{sub 1-z})Cr{sub 2}O{sub 4}(s). The liquid-solid distribution coefficient for the reaction, defined by the ratio of total zinc to iron ion concentrations in solution divided by the Zn(II)/Fe(II) ratio in the solid, z/(1-z), was found to be 0.184. This interpretation is consistent with the benefits of zinc treatment being concentration dependent.

  16. High temperature hydrogen sulfide adsorption on activated carbon - I. Effects of gas composition and metal addition

    USGS Publications Warehouse

    Cal, M.P.; Strickler, B.W.; Lizzio, A.A.

    2000-01-01

    Various types of activated carbon sorbents were evaluated for their ability to remove H2S from a simulated coal gas stream at a temperature of 550 ??C. The ability of activated carbon to remove H2S at elevated temperature was examined as a function of carbon surface chemistry (oxidation, thermal desorption, and metal addition), and gas composition. A sorbent prepared by steam activation, HNO3 oxidation and impregnated with Zn, and tested in a gas stream containing 0.5% H2S, 50% CO2 and 49.5% N2, had the greatest H2S adsorption capacity. Addition of H2, CO, and H2O to the inlet gas stream reduced H2S breakthrough time and H2S adsorption capacity. A Zn impregnated activated carbon, when tested using a simulated coal gas containing 0.5% H2S, 49.5% N2, 13% H2, 8.5% H2O, 21% CO, and 7.5% CO2, had a breakthrough time of 75 min, which was less than 25 percent of the length of breakthrough for screening experiments performed with a simplified gas mixture of 0.5% H2S, 50% CO2, and 49.5% N2.

  17. Cyclic-load crack growth in ASME SA-105 grade II steel in high-pressure hydrogen at ambient temperature

    NASA Technical Reports Server (NTRS)

    Walter, R. J.; Chandler, W. T.

    1976-01-01

    ASME SA-105 Grade II steel, which is used in high-pressure hydrogen compressor systems, is similar to steels used or considered for use in high-pressure hydrogen storage vessels and pipelines. This paper summarizes the results of a program conducted to provide cyclic-load crack growth rate (da/dN) data for a fracture mechanics analysis of a 15,000 psi hydrogen compressor facility which contains pulse quieter and after-cooler separator vessels constructed of the ASME SA-105 Grade II steel. Included in the program were tests performed to assist in establishing operating procedures that could minimize the effect of hydrogen on crack growth rates during operation.

  18. Recent Progress At The Idaho National Laboratory In High Temperature Electrolysis For Hydrogen And Syngas Production

    SciTech Connect

    C. Stoots; J. O'Brien; J. Herring; J. Hartvigsen

    2008-11-01

    This paper presents the most recent results of experiments conducted at the Idaho National Laboratory (INL) studying electrolysis of steam and coelectrolysis of steam / carbon dioxide in solid-oxide electrolysis stacks. Single button cell tests as well as multi-cell stack testing have been conducted. Multi-cell stack testing used 10 x 10 cm cells (8 x 8 cm active area) supplied by Ceramatec, Inc (Salt Lake City, Utah, USA) and ranged from 10 cell short stacks to 240 cell modules. Tests were conducted either in a bench-scale test apparatus or in a newly developed 5 kW Integrated Laboratory Scale (ILS) test facility. Gas composition, operating voltage, and operating temperature were varied during testing. The tests were heavily instrumented, and outlet gas compositions were monitored with a gas chromatograph. The ILS facility is currently being expanded to 15 kW testing capacity (H2 production rate based upon lower heating value).

  19. An Analysis of Methanol and Hydrogen Production via High-Temperature Electrolysis Using the Sodium Cooled Advanced Fast Reactor

    SciTech Connect

    Shannon M. Bragg-Sitton; Richard D. Boardman; Robert S. Cherry; Wesley R. Deason; Michael G. McKellar

    2014-03-01

    Integration of an advanced, sodium-cooled fast spectrum reactor into nuclear hybrid energy system (NHES) architectures is the focus of the present study. A techno-economic evaluation of several conceptual system designs was performed for the integration of a sodium-cooled Advanced Fast Reactor (AFR) with the electric grid in conjunction with wind-generated electricity. Cases in which excess thermal and electrical energy would be reapportioned within an integrated energy system to a chemical plant are presented. The process applications evaluated include hydrogen production via high temperature steam electrolysis and methanol production via steam methane reforming to produce carbon monoxide and hydrogen which feed a methanol synthesis reactor. Three power cycles were considered for integration with the AFR, including subcritical and supercritical Rankine cycles and a modified supercritical carbon dioxide modified Brayton cycle. The thermal efficiencies of all of the modeled power conversions units were greater than 40%. A thermal efficiency of 42% was adopted in economic studies because two of the cycles either performed at that level or could potentially do so (subcritical Rankine and S-CO2 Brayton). Each of the evaluated hybrid architectures would be technically feasible but would demonstrate a different internal rate of return (IRR) as a function of multiple parameters; all evaluated configurations showed a positive IRR. As expected, integration of an AFR with a chemical plant increases the IRR when “must-take” wind-generated electricity is added to the energy system. Additional dynamic system analyses are recommended to draw detailed conclusions on the feasibility and economic benefits associated with AFR-hybrid energy system operation.

  20. Enhanced performance and stability of high temperature proton exchange membrane fuel cell by incorporating zirconium hydrogen phosphate in catalyst layer

    NASA Astrophysics Data System (ADS)

    Barron, Olivia; Su, Huaneng; Linkov, Vladimir; Pollet, Bruno G.; Pasupathi, Sivakumar

    2015-03-01

    Zirconium hydrogen phosphate (ZHP) together with polytetrafluoroethylene (PTFE) polymer binder is incorporated into the catalyst layers (CLs) of ABPBI (poly(2,5-benzimidazole))-based high temperature polymer electrolyte membrane fuel cell (HT-PEMFCs) to improve its performance and durability. The influence of ZHP content (normalised with respect to dry PTFE) on the CL properties are structurally characterised by scanning electron microscopy (SEM) and mercury intrusion porosimetry. Electrochemical analyses of the resultant membrane electrode assemblies (MEAs) are performed by recording polarisation curves and impedance spectra at 160 °C, ambient pressure and humidity. The result show that a 30 wt.% ZHP/PTFE content in the CL is optimum for improving fuel cell performance, the resultant MEA delivers a peak power of 592 mW cm-2 at a cell voltage of 380 mV. Electrochemical impedance spectra (EIS) indicate that 30% ZHP in the CL can increase the proton conductivity compared to the pristine PTFE-gas diffusion electrode (GDE). A short term stability test (∼500 h) on the 30 wt.% ZHP/PTFE-GDE shows a remarkable high durability with a degradation rate as low as ∼19 μV h-1 at 0.2 A cm-2, while 195 μV h-1 was obtained for the pristine GDE.

  1. Anaerobic digestion of organic fraction of municipal solid waste combining two pretreatment modalities, high temperature microwave and hydrogen peroxide.

    PubMed

    Shahriari, Haleh; Warith, Mostafa; Hamoda, Mohamed; Kennedy, Kevin J

    2012-01-01

    In order to enhance anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW), pretreatment combining two modalities, microwave (MW) heating in presence or absence of hydrogen peroxide (H(2)O(2)) were investigated. The main pretreatment variables affecting the characteristics of the OFMSW were temperature (T) via MW irradiation and supplemental water additions of 20% and 30% (SWA20 and SW30). Subsequently, the focus of this study was to evaluate mesophilic batch AD performance in terms of biogas production, as well as changes in the characteristics of the OFMSW post digestion. A high MW induced temperature range (115-175°C) was applied, using sealed vessels and a bench scale MW unit equipped with temperature and pressure controls. Biochemical methane potential (BMP) tests were conducted on the whole OFMSW as well as the liquid fractions. The whole OFMSW pretreated at 115°C and 145°C showed 4-7% improvement in biogas production over untreated OFMSW (control). When pretreated at 175°C, biogas production decreased due to formation of refractory compounds, inhibiting the digestion. For the liquid fraction of OFMSW, the effect of pretreatment on the cumulative biogas production (CBP) was more pronounced for SWA20 at 145°C, with a 26% increase in biogas production after 8days of digestion, compared to the control. When considering the increased substrate availability in the liquid fraction after MW pretreatment, a 78% improvement in biogas production vs. the control was achieved. Combining MW and H(2)O(2) modalities did not have a positive impact on OFMSW stabilization and enhanced biogas production. In general, all samples pretreated with H(2)O(2) displayed a long lag phase and the CBP was usually lower than MW irradiated only samples. First order rate constant was calculated. PMID:21945550

  2. High efficiency stationary hydrogen storage

    SciTech Connect

    Hynek, S.; Fuller, W.; Truslow, S.

    1995-09-01

    Stationary storage of hydrogen permits one to make hydrogen now and use it later. With stationary hydrogen storage, one can use excess electrical generation capacity to power an electrolyzer, and store the resultant hydrogen for later use or transshipment. One can also use stationary hydrogen as a buffer at fueling stations to accommodate non-steady fueling demand, thus permitting the hydrogen supply system (e.g., methane reformer or electrolyzer) to be sized to meet the average, rather than the peak, demand. We at ADL designed, built, and tested a stationary hydrogen storage device that thermally couples a high-temperature metal hydride to a phase change material (PCM). The PCM captures and stores the heat of the hydriding reaction as its own heat of fusion (that is, it melts), and subsequently returns that heat of fusion (by freezing) to facilitate the dehydriding reaction. A key component of this stationary hydrogen storage device is the metal hydride itself. We used nickel-coated magnesium powder (NCMP) - magnesium particles coated with a thin layer of nickel by means of chemical vapor deposition (CVD). Magnesium hydride can store a higher weight fraction of hydrogen than any other practical metal hydride, and it is less expensive than any other metal hydride. We designed and constructed an experimental NCM/PCM reactor out of 310 stainless steel in the form of a shell-and-tube heat exchanger, with the tube side packed with NCMP and the shell side filled with a eutectic mixture of NaCL, KCl, and MgCl{sub 2}. Our experimental results indicate that with proper attention to limiting thermal losses, our overall efficiency will exceed 90% (DOE goal: >75%) and our overall system cost will be only 33% (DOE goal: <50%) of the value of the delivered hydrogen. It appears that NCMP can be used to purify hydrogen streams and store hydrogen at the same time. These prospects make the NCMP/PCM reactor an attractive component in a reformer-based hydrogen fueling station.

  3. Emergence of a High-Temperature Superconductivity in Hydrogen Cycled pd Compounds as AN Evidence for Superstoihiometric H/d Sites

    NASA Astrophysics Data System (ADS)

    Lipson, Andrei; Castano, Carlos; Miley, George; Lipson, Andrei; Lyakhov, Boris; Mitin, Alexander

    2006-02-01

    Transport and magnetic properties of hydrogen cycled PdHx and Pd/PdO:Hx (x ~ (4/6) × 10-4) nano-composite consisting of a Pd matrix with hydrogen trapped inside dislocation cores have been studied. The results suggest emergence of a high-temperature superconductivity state of a condensed hydrogen phase confined inside deep dislocation cores in the Pd matrix. The possible role of hydrogen/deuterium filled dislocation nano-tubes is discussed. These dislocation cores could be considered as active centers of LENR triggering due to (i) short D-D separation distance (~Bohr radius); (ii) high-local D-loading in the Pd and the corresponding effective lattice compression; (iii) a large optic phonon energy resulting in a most effective lattice-nuclei energy transfer.

  4. Evidence for Dominant Role of Tunneling in Condensed Phases and at High Temperatures: Double Hydrogen Transfer in Porphycenes.

    PubMed

    Ciąćka, Piotr; Fita, Piotr; Listkowski, Arkadiusz; Radzewicz, Czesław; Waluk, Jacek

    2016-01-21

    Investigation of the double hydrogen transfer in porphycene, its 2,7,12,17-tetra-tert-butyl derivative, and their N-deuterated isotopologues revealed the dominant role of tunneling, even at room temperature in condensed phase. Ultrafast optical spectroscopy with polarized light employed in a wide range of temperatures allowed the identification and evaluation of contributions of two tunneling modes: vibrational ground-state tunneling, occurring from the zero vibrational level, and vibrationally activated, via a large amplitude, low-frequency mode. Good correspondence was found between the rates of incoherent tunneling occurring in condensed phase and the values estimated on the basis of tunneling splittings observed in molecules isolated in supersonic jets or helium nanodroplets. The results provide solid experimental insight into widely proposed quantum facets of ubiquitous hydrogen-transfer phenomena. PMID:26727277

  5. Development of Tritium Permeation Analysis Code and Tritium Transport in a High Temperature Gas-Cooled Reactor Coupled with Hydrogen Production System

    SciTech Connect

    Chang H. Oh; Eung S. Kim; Mike Patterson

    2010-06-01

    Abstract – A tritium permeation analyses code (TPAC) was developed by Idaho National Laboratory for the purpose of analyzing tritium distributions in very high temperature reactor (VHTR) systems, including integrated hydrogen production systems. A MATLAB SIMULINK software package was used in developing the code. The TPAC is based on the mass balance equations of tritium-containing species and various forms of hydrogen coupled with a variety of tritium sources, sinks, and permeation models. In the TPAC, ternary fission and neutron reactions with 6Li, 7Li 10B, and 3He were taken into considerations as tritium sources. Purification and leakage models were implemented as main tritium sinks. Permeation of tritium and H2 through pipes, vessels, and heat exchangers were considered as main tritium transport paths. In addition, electroyzer and isotope exchange models were developed for analyzing hydrogen production systems, including high temperature electrolysis and sulfur-iodine processes.

  6. Thermal-Hydraulic Analyses of Heat Transfer Fluid Requirements and Characteristics for Coupling A Hydrogen Production Plant to a High-Temperature Nuclear Reactor

    SciTech Connect

    C. B. Davis; C. H. Oh; R. B. Barner; D. F. Wilson

    2005-06-01

    The Department of Energy is investigating the use of high-temperature nuclear reactors to produce hydrogen using either thermochemical cycles or high-temperature electrolysis. Although the hydrogen production processes are in an early stage of development, coupling either of these processes to the hightemperature reactor requires both efficient heat transfer and adequate separation of the facilities to assure that off-normal events in the production facility do not impact the nuclear power plant. An intermediate heat transport loop will be required to separate the operations and safety functions of the nuclear and hydrogen plants. A next generation high-temperature reactor could be envisioned as a single-purpose facility that produces hydrogen or a dual-purpose facility that produces hydrogen and electricity. Early plants, such as the proposed Next Generation Nuclear Plant, may be dual-purpose facilities that demonstrate both hydrogen and efficient electrical generation. Later plants could be single-purpose facilities. At this stage of development, both single- and dual-purpose facilities need to be understood. Seven possible configurations for a system that transfers heat between the nuclear reactor and the hydrogen and/or electrical generation plants were identified. These configurations included both direct and indirect cycles for the production of electricity. Both helium and liquid salts were considered as the working fluid in the intermediate heat transport loop. Methods were developed to perform thermalhydraulic and cycle-efficiency evaluations of the different configurations and coolants. The thermalhydraulic evaluations estimated the sizes of various components in the intermediate heat transport loop for the different configurations. The relative sizes of components provide a relative indication of the capital cost associated with the various configurations. Estimates of the overall cycle efficiency of the various configurations were also determined. The

  7. Effect of high-temperature water and hydrogen on the fracture behavior of a low-alloy reactor pressure vessel steel

    NASA Astrophysics Data System (ADS)

    Roychowdhury, S.; Seifert, H.-P.; Spätig, P.; Que, Z.

    2016-09-01

    Structural integrity of reactor pressure vessels (RPV) is critical for safety and lifetime. Possible degradation of fracture resistance of RPV steel due to exposure to coolant and hydrogen is a concern. In this study tensile and elastic-plastic fracture mechanics (EPFM) tests in air (hydrogen pre-charged) and EFPM tests in hydrogenated/oxygenated high-temperature water (HTW) was done, using a low-alloy RPV steel. 2-5 wppm hydrogen caused embrittlement in air tensile tests at room temperature (25 °C) and at 288 °C, effects being more significant at 25 °C and in simulated weld coarse grain heat affected zone material. Embrittlement at 288 °C is strain rate dependent and is due to localized plastic deformation. Hydrogen pre-charging/HTW exposure did not deteriorate the fracture resistance at 288 °C in base metal, for investigated loading rate range. Clear change in fracture morphology and deformation structures was observed, similar to that after air tests with hydrogen.

  8. Experimental investigation of solid hydrogen pellet ablation in high-temperature plasmas using holographic interferometry and other diagnostics

    SciTech Connect

    Thomas, Jr., C. E.

    1981-03-01

    The technology currently most favored for the refueling of fusion reactors is the high-velocity injection of solid hydrogen pellets. Design details are presented for a holographic interferometer/shadowgraph used to study the microscopic characteristics of a solid hydrogen pellet ablating in an approx. 1-keV plasma. Experimental data are presented for two sets of experiments in which the interferometer/shadowgraph was used to study approx. 1-mm-diam solid hydrogen pellets injected into the Impurity Study Experiment (ISX-B) tokamak at Oak Ridge National Laboratory (ORNL) at velocities of 1000 m/s. In addition to the use of the holographic interferometer, the pellet ablation process is diagnosed by studying the emission of Balmer-alpha photons and by using the available tokamak diagnostics (Thomson scattering, microwave/far-infrared interferometer, pyroelectric radiometer, hard x-ray detector).

  9. Low-temperature synthesis of microcrystalline 3C-SiC film by high-pressure hydrogen-plasma-enhanced chemical transport

    NASA Astrophysics Data System (ADS)

    Ohmi, Hiromasa; Hori, Takahiro; Mori, Tetsuya; Kakiuchi, Hiroaki; Yasutake, Kiyoshi

    2011-06-01

    The synthesis of microcrystalline 3C-SiC films on glass substrates at relatively low temperatures (<=600 °C) by the plasma-enhanced chemical transport method was carried out using a high-pressure pure hydrogen glow discharge. This method used the chemical erosion products of graphite and silicon in the hydrogen plasma as the deposition source. The temperature dependence of the etching rate of graphite and the generated volatile C-species were investigated by exposing sintered graphite to a pure hydrogen plasma at 100 Torr. Infrared absorption gas analysis indicated that the C-related film precursor generated from the graphite was mainly CH4. The etch rate of graphite reached a maximum at a sample temperature of 200 °C. The deposition rate of the SiC film prepared at a hydrogen pressure of 200 Torr increased monotonically from 14 to 29 nm min-1 with an increase in substrate temperature (Tsub) from 100 to 600 °C. The Si/C composition ratio in the films was independent of Tsub and all the film compositions were nearly stoichiometric. The prepared SiC films were microcrystalline 3C-SiC. Raman spectroscopy indicated that the film quality significantly depends on Tsub. The electrical conductivity of the films at room temperature was found to increase exponentially from 3 × 10-4 to 1.7 S cm-1 with Tsub.

  10. High-temperature stability of c-Si surface passivation by thick PECVD Al2O3 with and without hydrogenated capping layers

    NASA Astrophysics Data System (ADS)

    Saint-Cast, Pierre; Kania, Daniel; Heller, René; Kuehnhold, Saskia; Hofmann, Marc; Rentsch, Jochen; Preu, Ralf

    2012-08-01

    We are studying the thermal stability of thick hydrogenated amorphous aluminum oxide (Al2O3) layers (20-50 nm) prepared by a high-throughput plasma-enhanced chemical-vapor-deposition (PECVD) technique for the electrical passivation of crystalline silicon surfaces. These passivation layers can be applied alone or covered by a capping layer like amorphous hydrogenated silicon nitride (SiNx) or amorphous hydrogenated silicon oxide (SiOx), also prepared by PECVD. After firing at 870 °C for approximately 3 s, the layers show blistering for Al2O3 of 30 nm or higher, independently from the capping layer. For thinner Al2O3, no blistering can be observed even using scanning electron microscope (SEM). Very long carrier lifetimes up to 900 μs was obtained in passivated p-Si (1 Ωcm) wafer after annealing and firing, without observing a strong influence of the layer thickness and the capping layer. All the layer stacks, including the stacks with SiNx capping layer, show high negative charge densities in the layer (1-4 × 1012 cm-2). Additionally, low interface defect densities (˜1011 cm-2 eV-1), which could be achieved with and without a hydrogenated capping layer, were measured even after firing. To explain these phenomena, hydrogen concentration depth profiles were measured by nuclear reaction analysis. These measurements have shown that, at the Al2O3-Si interface, hydrogen atomic concentration ranging 5-7% after annealing and 4% after firing are obtained independently from the capping hydrogen concentration. We conclude that PECVD Al2O3 layers of 20 nm or thicker can provide enough hydrogen to passivate the interface defects, even after a high temperature step. However, the layer thickness should be limited to 30 nm in order to avoid the blistering.

  11. THE IMPACT OF TRACE ADDITIVES ON THE APPARENT SOLUBILITY OF HYDROGEN IN HEAVY OIL AND RELATED FEEDSTOCKS AT LOW AND HIGH TEMPERATURES

    SciTech Connect

    Jalal Abedi

    2002-09-01

    A systematic investigation was conducted to provide an accurate determination of hydrogen solubility in liquid media in temperatures in the range of 25-250 C and pressures in the range of 0.5-8 MPa. Results were obtained by an indirect gas solubility measurement method. The method was intended for use with high-resolution camera. The hydrogen solubility measurements were indirect and were based on pressure changes at constant temperature and measured volumes. Since the volume of the view cell was fixed the volume available for the vapor phase could be determined by measuring the location of the liquid-vapor interface. The interface was located to within the height of one pixel using high-resolution camera, which added {+-} 0.4 ml to the uncertainty of the vapor volume. Liquid-liquid interface locations were measured with equal precision. The accuracy of the method was illustrated through hydrogen solubility measurements in hexadecane and tetralin, which were in close agreement with the values available in the literature. Hydrogen solubilities in Athabasca bitumen vacuum bottoms (ABVB) were reported over a broad range of temperatures (80-250 C) and pressures (0.5-8 MPa).

  12. Metal-Borohydride-Modified Zr(BH4 )4 ⋅8 NH3 : Low-Temperature Dehydrogenation Yielding Highly Pure Hydrogen.

    PubMed

    Huang, Jianmei; Ouyang, Liuzhang; Gu, Qinfen; Yu, Xuebin; Zhu, Min

    2015-10-12

    Due to its high hydrogen density (14.8 wt %) and low dehydrogenation peak temperature (130 °C), Zr(BH4 )4 ⋅8 NH3 is considered to be one of the most promising hydrogen-storage materials. To further decrease its dehydrogenation temperature and suppress its ammonia release, a strategy of introducing LiBH4 and Mg(BH4 )2 was applied to this system. Zr(BH4 )4 ⋅8 NH3 -4 LiBH4 and Zr(BH4 )4 ⋅8 NH3 -2 Mg(BH4 )2 composites showed main dehydrogenation peaks centered at 81 and 106 °C as well as high hydrogen purities of 99.3 and 99.8 mol % H2 , respectively. Isothermal measurements showed that 6.6 wt % (within 60 min) and 5.5 wt % (within 360 min) of hydrogen were released at 100 °C from Zr(BH4 )4 ⋅8 NH3 -4 LiBH4 and Zr(BH4 )4 ⋅8 NH3 -2 Mg(BH4 )2 , respectively. The lower dehydrogenation temperatures and improved hydrogen purities could be attributed to the formation of the diammoniate of diborane for Zr(BH4 )4 ⋅8 NH3 -4 LiBH4 , and the partial transfer of NH3 groups from Zr(BH4 )4 ⋅8 NH3 to Mg(BH4 )2 for Zr(BH4 )4 ⋅8 NH3 -2 Mg(BH4 )2 , which result in balanced numbers of BH4 and NH3 groups and a more active H(δ+) ⋅⋅⋅(-δ) H interaction. These advanced dehydrogenation properties make these two composites promising candidates as hydrogen-storage materials. PMID:26315468

  13. Anaerobic digestion of organic fraction of municipal solid waste combining two pretreatment modalities, high temperature microwave and hydrogen peroxide

    SciTech Connect

    Shahriari, Haleh; Warith, Mostafa; Hamoda, Mohamed; Kennedy, Kevin J.

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Microwave and H{sub 2}O{sub 2} pretreatment were studied to enhance anaerobic digestion of organic waste. Black-Right-Pointing-Pointer The whole waste pretreated at 115 Degree-Sign C or 145 Degree-Sign C had the highest biogas production. Black-Right-Pointing-Pointer Biogas production of the whole waste decreased at 175 Degree-Sign C due to formation of refractory compounds. Black-Right-Pointing-Pointer Pretreatment to 145 Degree-Sign C and 175 Degree-Sign C were the best when considering only the free liquid fraction. Black-Right-Pointing-Pointer H{sub 2}O{sub 2} pretreatment had a lag phase and the biogas production was not higher than MW pretreated samples. - Abstract: In order to enhance anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW), pretreatment combining two modalities, microwave (MW) heating in presence or absence of hydrogen peroxide (H{sub 2}O{sub 2}) were investigated. The main pretreatment variables affecting the characteristics of the OFMSW were temperature (T) via MW irradiation and supplemental water additions of 20% and 30% (SWA20 and SW30). Subsequently, the focus of this study was to evaluate mesophilic batch AD performance in terms of biogas production, as well as changes in the characteristics of the OFMSW post digestion. A high MW induced temperature range (115-175 Degree-Sign C) was applied, using sealed vessels and a bench scale MW unit equipped with temperature and pressure controls. Biochemical methane potential (BMP) tests were conducted on the whole OFMSW as well as the liquid fractions. The whole OFMSW pretreated at 115 Degree-Sign C and 145 Degree-Sign C showed 4-7% improvement in biogas production over untreated OFMSW (control). When pretreated at 175 Degree-Sign C, biogas production decreased due to formation of refractory compounds, inhibiting the digestion. For the liquid fraction of OFMSW, the effect of pretreatment on the cumulative biogas production (CBP

  14. On-line hydrogen-isotope measurements of organic samples using elemental chromium: an extension for high temperature elemental-analyzer techniques.

    PubMed

    Gehre, Matthias; Renpenning, Julian; Gilevska, Tetyana; Qi, Haiping; Coplen, Tyler B; Meijer, Harro A J; Brand, Willi A; Schimmelmann, Arndt

    2015-01-01

    The high temperature conversion (HTC) technique using an elemental analyzer with a glassy carbon tube and filling (temperature conversion/elemental analysis, TC/EA) is a widely used method for hydrogen isotopic analysis of water and many solid and liquid organic samples with analysis by isotope-ratio mass spectrometry (IRMS). However, the TC/EA IRMS method may produce inaccurate δ(2)H results, with values deviating by more than 20 mUr (milliurey = 0.001 = 1‰) from the true value for some materials. We show that a single-oven, chromium-filled elemental analyzer coupled to an IRMS substantially improves the measurement quality and reliability for hydrogen isotopic compositions of organic substances (Cr-EA method). Hot chromium maximizes the yield of molecular hydrogen in a helium carrier gas by irreversibly and quantitatively scavenging all reactive elements except hydrogen. In contrast, under TC/EA conditions, heteroelements like nitrogen or chlorine (and other halogens) can form hydrogen cyanide (HCN) or hydrogen chloride (HCl) and this can cause isotopic fractionation. The Cr-EA technique thus expands the analytical possibilities for on-line hydrogen-isotope measurements of organic samples significantly. This method yielded reproducibility values (1-sigma) for δ(2)H measurements on water and caffeine samples of better than 1.0 and 0.5 mUr, respectively. To overcome handling problems with water as the principal calibration anchor for hydrogen isotopic measurements, we have employed an effective and simple strategy using reference waters or other liquids sealed in silver-tube segments. These crimped silver tubes can be employed in both the Cr-EA and TC/EA techniques. They simplify considerably the normalization of hydrogen-isotope measurement data to the VSMOW-SLAP (Vienna Standard Mean Ocean Water-Standard Light Antarctic Precipitation) scale, and their use improves accuracy of the data by eliminating evaporative loss and associated isotopic fractionation while

  15. Preparation of Proton Conductor SrZr1-xYxO3-α for Pure Hydrogen Separation in high temperature range

    NASA Astrophysics Data System (ADS)

    Konishi, Hirokazu; Nishimura, Hiroshi; Usui, Tateo; Iwao, Katayama

    The SrZr1-xYxO3-α of proton conductor was prepared by normal sintering and SPS (spark plasma sintering) methods in order to separate pure hydrogen gas from H2-containing mixed gases in high temperature range. The SrZr1-xYxO3-α has high proton conductivity under H2 gas atmosphere from 973 K to 1273 K. In this hydrogen separation system, hydrogen is oxidized to proton at the anode, and proton is reduced to hydrogen at the cathode using proton conductor by electrochemical method. Proton conductors SrZr0.9Y0.1O3-α obtained by normal sintering at 1580°C for 10 h and SPS at 1500°C for 3 min were found to be single phase of perovskite structure. Furthermore, the crystal structure of SrZr0.9Y0.1O3-α was chemically stable under H2 and CO2 gases atmosphere. Relative densities of SrZr0.9Y0.1O3-α obtained by SPS at 1400 and 1500°C were over 95 %. Furthermore, the relative density increased with sintering temperature and time of SPS. The proton conductivity of SrZr0.9Y0.1O3-α of SPS increased with sintering temperature, and was higher than one of normal sintering under wet 10 % H2 and Ar gases atmosphere. From the measurement of EMF (electromotive force) of hydrogen concentration cell at 800°C, the ionic transport number of SrZr0.9Y0.1O3-α of SPS at 1400°C for 5 min was about 1, and the electron conductivity was considerably low.

  16. Interaction between a high density-low temperature plasma and a frozen hydrogen pellet in a railgun injector

    SciTech Connect

    Grapperhaus, M.J.

    1993-10-01

    A model has been developed which describes the ablation process of frozen hydrogen pellets in an electromagnetic railgun. The model incorporates the neutral gas shielding model in which the pellet surface is heated by incident electrons from the plasma arc. The heated surface then ablates, forming a neutral cloud which attenuates the incoming electrons. The energy lost in the cloud by the electrons heats the ablatant material as it flows into the plasma arc. Under steady-state conditions, a scaling law for the ablation rate was derived as a function of plasma-arc temperature and density. In addition, flow conditions and the criteria for the existence of a steady-state solution were formulated and subsequently examined under simplifying assumptions. Comparison with experimentally observed ablation rates shows good qualitative agreement.

  17. Hydrogen incorporation into high temperature protonic conductors: Nuclear microprobe microanalysis by means of 1H(p, p) 1H scattering

    NASA Astrophysics Data System (ADS)

    Berger, P.; Gallien, J.-P.; Khodja, H.; Daudin, L.; Berger, M.-H.; Sayir, A.

    2006-08-01

    Protonic conductivity of some solid state materials at an intermediate temperature range (400-600 °C), referred as high temperature protonic conductor (HTPC), suggests their application as electrolytes in electrochemical cells, batteries, sensors, etc. Among them, some perovskites can be protonic and electronic conductors. Several obstacles remain to achieve the full potential of these ceramic membranes, among them the lack of measurement techniques and of an unambiguous model for conductivity. A precise understanding of the transport mechanisms requires local profiling of hydrogen concentrations within the microstructure of the ceramic. We have used the nuclear microprobe of the Laboratoire Pierre SÜE to investigate quantitatively the spatial distribution of hydrogen after water heat treatment of textured perovskites, SrCe0.9Y0.1O3-δ and Sr3Ca1+xNb2-xO9-δ, x = 0.18, synthesized according to a melt-process developed at NASA GRC. A not very common method has been developed for hydrogen measurements in thin samples, 1H(p, p)1H elastic recoil coincidence spectrometry (ERCS). Early experiments have evidenced hydrogen concentration enhancement within grain boundaries.

  18. CARS study of linewidths of the Q-branch of hydrogen molecules at high temperatures in a pulsed high-pressure H{sub 2}-O{sub 2} combustion chamber

    SciTech Connect

    Vereschagin, Konstantin A; Vereschagin, Alexey K; Smirnov, Valery V; Stelmakh, O M; Fabelinskii, V I; Clauss, W; Klimenko, D N; Oschwald, M

    2005-03-31

    The results of measurements of individual line widths of the Q-branch of a hydrogen molecule and the corresponding coefficients of broadening caused by collisions with water molecules at T = 2700 K in a repetitively pulsed high-pressure (50-200 atm) hydrogen-oxygen combustion chamber are presented. CARS spectra of individual Q{sub 1}-Q{sub 7} hydrogen lines, pressure pulses, and the broadband CARS spectra of the entire Q-branch of hydrogen are recorded simultaneously during a single laser pulse. The shape of line profiles was analysed using a Fabry-Perot interferometer. The temperature in the volume being probed was determined from the 'broadband' CARS spectra. The entire body of the experimental results gives information on the spectral linewidths, temperature and pressure in the combustion chamber during CARS probing. (laser applications and other topics in quantum electronics)

  19. Using A High-Temperature Hydrogen Co-Generation Reactor To Optimize Both Economic and Environmental Performance

    SciTech Connect

    Weimar, Mark R.; Wood, Thomas W.; Reichmuth, Barbara A.; Johnson, Wayne L.

    2004-07-01

    This paper reports the analysis of outcomes for a 3000 MWt HTGR plant, given price and cost assumptions, and determines what level of hydrogen and electricity production would optimize the plant economically and environmentally (carbon reduction). Coupling nuclear power with hydrogen production could fundamentally alter the character of the nuclear industry and nuclear technology’s development path. For this to happen, the hydrogen economy will have to be realized, and a new generation of reactors technically suitable to co-production of hydrogen with electric power must be developed and proven. The paper shows that the tradeoff between producing hydrogen through steam methane reformation and producing electricity is disproportionate and would require significant price increases for electricity to change the outcomes. It also found that estimate of shadow values for carbon credits was in the range now under discussion.

  20. High temperature electrolytic recovery of oxygen from gaseous effluents from the carbo-chlorination of lunar anorthite and the hydrogenation of ilmenite: A theoretical study

    NASA Technical Reports Server (NTRS)

    Erstfield, T. E.; Williams, R. J.

    1979-01-01

    A thermodynamic analysis discusses the compositions of gaseous effluents from the reaction of carbon and chlorine and of hydrogen with lunar anorthite and ilmenite, respectively. The computations consider the effects of the indigenous volatiles on the solid/gas reactions and on the composition of the effluent gases. A theoretical parameterization of the high temperature electrolysis of such gases is given for several types of solid ceramic electrolytes, and the effect of oxygen removal on the effluents is computed. Potential chemical interactions between the gases and the ceramic electrolytes are analyzed and discussed.

  1. Nanodiamond for hydrogen storage: temperature-dependent hydrogenation and charge-induced dehydrogenation.

    PubMed

    Lai, Lin; Barnard, Amanda S

    2012-02-21

    Carbon-based hydrogen storage materials are one of hottest research topics in materials science. Although the majority of studies focus on highly porous loosely bound systems, these systems have various limitations including use at elevated temperature. Here we propose, based on computer simulations, that diamond nanoparticles may provide a new promising high temperature candidate with a moderate storage capacity, but good potential for recyclability. The hydrogenation of nanodiamonds is found to be easily achieved, in agreement with experiments, though we find the stability of hydrogenation is dependent on the morphology of nanodiamonds and surrounding environment. Hydrogenation is thermodynamically favourable even at high temperature in pure hydrogen, ammonia, and methane gas reservoirs, whereas water vapour can help to reduce the energy barrier for desorption. The greatest challenge in using this material is the breaking of the strong covalent C-H bonds, and we have identified that the spontaneous release of atomic hydrogen may be achieved through charging of hydrogenated nanodiamonds. If the degree of induced charge is properly controlled, the integrity of the host nanodiamond is maintained, which indicates that an efficient and recyclable approach for hydrogen release may be possible. PMID:22089370

  2. High capacity hydrogen storage nanocomposite materials

    DOEpatents

    Zidan, Ragaiy; Wellons, Matthew S

    2015-02-03

    A novel hydrogen absorption material is provided comprising a mixture of a lithium hydride with a fullerene. The subsequent reaction product provides for a hydrogen storage material which reversibly stores and releases hydrogen at temperatures of about 270.degree. C.

  3. High Temperature Heat Exchanger Project

    SciTech Connect

    Anthony E. Hechanova, Ph.D.

    2008-09-30

    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  4. Neutral hydrogen in high-temperature pinch plasmas and its influence on the ionization dynamics of impurities

    NASA Astrophysics Data System (ADS)

    Preissing, N.; König, R.; Kolk, K. H.; Kunze, H.-J.

    1992-08-01

    The neutral-hydrogen density in a hot pinch plasma and in the surrounding halo is investigated spectroscopically, and its influence on the ionization dynamics of impurity ions is analyzed. The results are employed in the analysis of effective-ionization-rate coefficients, which are derived for Si viii to Si xii from the time evolution of the respective ions in the plasma.

  5. Hydrogenation of solid hydrogen cyanide HCN and methanimine CH2NH at low temperature

    NASA Astrophysics Data System (ADS)

    Theule, P.; Borget, F.; Mispelaer, F.; Danger, G.; Duvernay, F.; Guillemin, J. C.; Chiavassa, T.

    2011-10-01

    Context. Hydrogenation reactions dominate grain surface chemistry in dense molecular clouds and lead to the formation of complex saturated molecules in the interstellar medium. Aims: We investigate in the laboratory the hydrogenation reaction network of hydrogen cyanide HCN. Methods: Pure hydrogen cyanide HCN and methanimine CH2NH ices are bombarded at room temperature by H-atoms in an ultra-high vacuum experiment. Warm H-atoms are generated in an H2 plasma source. The ices are monitored with Fourier-transform infrared spectroscopy in reflection absorption mode. The hydrogenation products are detected in the gas phase by mass spectroscopy during temperature-programmed desorption experiments. Results: HCN hydrogenation leads to the formation of methylamine CH3NH2, and CH2NH hydrogenation leads to the formation of methylamine CH3NH2, suggesting that CH2NH can be a hydrogenation-intermediate species between HCN and CH3NH2. Conclusions: In cold environments the HCN hydrogenation reaction can produce CH3NH2, which is known to be a glycine precursor, and to destroy solid-state HCN, preventing its observation in molecular clouds ices.

  6. Metallic Hydrogen - Potentially a High Energy Rocket Propellant

    NASA Technical Reports Server (NTRS)

    Cole, John; Silvera, Ike

    2007-01-01

    Pure metallic hydrogen is predicted to have a specific impulse (Isp) of 1700 seconds, but the reaction temperature is too high for current engine materials. Diluting metallic hydrogen with liquid hydrogen can reduce the reaction temperature to levels compatible with current material limits and still provide an Isp greater than 900 s. Metallic hydrogen has not yet been produced on earth, but experimental techniques exist that may change this situation. This paper will provide a brief description of metallic hydrogen and the status of experiments that may soon produce detectable quantities of this material in the lab. Also provided are some characteristics for diluted metallic hydrogen engines and launch vehicles.

  7. High Temperature Structural Foam

    NASA Technical Reports Server (NTRS)

    Weiser, Erik S.; Baillif, Faye F.; Grimsley, Brian W.; Marchello, Joseph M.

    1997-01-01

    The Aerospace Industry is experiencing growing demand for high performance polymer foam. The X-33 program needs structural foam insulation capable of retaining its strength over a wide range of environmental conditions. The High Speed Research Program has a need for low density core splice and potting materials. This paper reviews the state of the art in foam materials and describes experimental work to fabricate low density, high shear strength foam which can withstand temperatures from -220 C to 220 C. Commercially available polymer foams exhibit a wide range of physical properties. Some with densities as low as 0.066 g/cc are capable of co-curing at temperatures as high as 182 C. Rohacell foams can be resin transfer molded at temperatures up to 180 C. They have moduli of elasticity of 0.19 MPa, tensile strengths of 3.7 Mpa and compressive strengths of 3.6 MPa. The Rohacell foams cannot withstand liquid hydrogen temperatures, however Imi-Tech markets Solimide (trademark) foams which withstand temperatures from -250 C to 200 C, but they do not have the required structural integrity. The research activity at NASA Langley Research Center focuses on using chemical blowing agents to produce polyimide thermoplastic foams capable of meeting the above performance requirements. The combination of blowing agents that decompose at the minimum melt viscosity temperature together with plasticizers to lower the viscosity has been used to produce foams by both extrusion and oven heating. The foams produced exhibit good environmental stability while maintaining structural properties.

  8. Fluid hydrogen at high density - Pressure dissociation

    NASA Technical Reports Server (NTRS)

    Saumon, Didier; Chabrier, Gilles

    1991-01-01

    A model for the Helmholtz free energy of fluid hydrogen at high density and high temperature is developed. This model aims at describing both pressure and temperature dissociation and ionization and bears directly on equations of state of partially ionized plasmas, as encountered in astrophysical situations and high-pressure experiments. This paper focuses on a mixture of hydrogen atoms and molecules and is devoted to the study of the phenomenon of pressure dissociation at finite temperatures. In the present model, the strong interactions are described with realistic potentials and are computed with a modified Weeks-Chandler-Andersen fluid perturbation theory that reproduces Monte Carlo simulations to better than 3 percent. Theoretical Hugoniot curves derived from the model are in excellent agreement with experimental data.

  9. A low-temperature co-fired ceramic micro-reactor system for high-efficiency on-site hydrogen production

    NASA Astrophysics Data System (ADS)

    Jiang, Bo; Maeder, Thomas; Santis-Alvarez, Alejandro J.; Poulikakos, Dimos; Muralt, Paul

    2015-01-01

    A ceramic-based, meso-scale fuel processor for on-board production of syngas fuel was demonstrated for applications in micro-scale solid-oxide fuel cells (μ-SOFCs). The processor had a total dimension of 12 mm × 40 mm × 2 mm, the gas reforming micro reactor occupying the hot end of a cantilever had outer dimensions of 12 × 18 mm. The device was fabricated through a novel progressive lamination process in low-temperature co-fired ceramic (LTCC) technology. Both, heating function and desired fluidic structures were integrated monolithically into the processor. Using catalytic partial oxidation of a hydrocarbon fuel (propane) as a reaction model, a thermally self-sustaining hydrogen production was achieved. The output flow is sufficiently high to drive an optimized single membrane μSOFC cell of about the same footprint as the micro reactor. Microsystem design, fabrication, catalyst integration as well as the chemical characterization are discussed in detail.

  10. Fluid hydrogen at high density - Pressure ionization

    NASA Technical Reports Server (NTRS)

    Saumon, Didier; Chabrier, Gilles

    1992-01-01

    The Helmholtz-free-energy model for nonideal mixtures of hydrogen atoms and molecules by Saumon and Chabrier (1991) is extended to describe dissociation and ionization in similar mixtures in chemical equilibrium. A free-energy model is given that describes partial ionization in the pressure and temperature ionization region. The plasma-phase transition predicted by the model is described for hydrogen mixtures including such components as H2, H, H(+), and e(-). The plasma-phase transition has a critical point at Tc = 15,300 K and Pc = 0.614 Mbar, and thermodynamic instability is noted in the pressure-ionization regime. The pressure dissociation and ionization of fluid hydrogen are described well with the model yielding information on the nature of the plasma-phase transition. The model is shown to be valuable for studying dissociation and ionization in astrophysical objects and in high-pressure studies where pressure and temperature effects are significant.

  11. Gas chromatography flow rates for determining deuterium/hydrogen ratios of natural gas by gas chromatography/high-temperature conversion/isotope ratio mass spectrometry.

    PubMed

    Jia, Wanglu; Peng, Ping'an; Liu, Jinzhong

    2008-08-01

    The effects of the gas chromatography flow rate on the determination of the deuterium/hydrogen (D/H) ratios of natural gas utilising gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/TC/IRMS) have been evaluated. In general, the measured deltaD values of methane, ethane and propane decrease with increase in column flow rate. When the column flow rate is 1 mL/min or higher, which is commonly used for the determination of D/H ratios of natural gas, the organic H in gas compounds may not be completely converted into hydrogen gas. Based on the results of experiments conducted on a GC column with an i.d. of 0.32 mm, a GC flow rate of 0.6 mL/min is proposed for determining the D/H ratios of natural gas by GC/TC/IRMS. Although this value may be dependent on the instrument conditions used in this work, we believe that correct deltaD values of organic compounds with a few carbon atoms are obtained only when relatively low GC flow rates are used for D/H analysis by GC/TC/IRMS. Moreover, as the presence of trace water could significantly affect the determination of D/H ratios, a newly designed inlet liner was used to remove trace water contained in some gas samples. PMID:18636428

  12. Quantifying residual hydrogen adsorption in low-temperature STMs

    NASA Astrophysics Data System (ADS)

    Natterer, F. D.; Patthey, F.; Brune, H.

    2013-09-01

    We report on low-temperature scanning tunneling microscopy observations demonstrating that individual Ti atoms on hexagonal boron nitride dissociate and adsorb hydrogen without measurable reaction barrier. The clean and hydrogenated states of the adatoms are clearly discerned by their apparent height and their differential conductance revealing the Kondo effect upon hydrogenation. Measurements at 50 K and 5 × 10- 11 mbar indicate a sizable hydrogenation within only 1 h originating from the residual gas pressure, whereas measurements at 4.7 K can be carried out for days without H2 contamination problems. However, heating up a low-T STM to operate it at variable temperature results in very sudden hydrogenation at around 17 K that correlates with a sharp peak in the total chamber pressure. From a quantitative analysis we derive the desorption energies of H2 on the cryostat walls. We find evidence for hydrogen contamination also during Ti evaporation and propose a strategy on how to dose transition metal atoms in the cleanliest fashion. The present contribution raises awareness of hydrogenation under seemingly ideal ultra-high vacuum conditions, it quantifies the H2 uptake by isolated transition metal atoms and its thermal desorption from the gold plated cryostat walls.

  13. Mechanistic studies of water electrolysis and hydrogen electro-oxidation on high temperature ceria-based solid oxide electrochemical cells.

    PubMed

    Zhang, Chunjuan; Yu, Yi; Grass, Michael E; Dejoie, Catherine; Ding, Wuchen; Gaskell, Karen; Jabeen, Naila; Hong, Young Pyo; Shavorskiy, Andrey; Bluhm, Hendrik; Li, Wei-Xue; Jackson, Gregory S; Hussain, Zahid; Liu, Zhi; Eichhorn, Bryan W

    2013-08-01

    Through the use of ambient pressure X-ray photoelectron spectroscopy (APXPS) and a single-sided solid oxide electrochemical cell (SOC), we have studied the mechanism of electrocatalytic splitting of water (H2O + 2e(-) → H2 + O(2-)) and electro-oxidation of hydrogen (H2 + O(2-) → H2O + 2e(-)) at ∼700 °C in 0.5 Torr of H2/H2O on ceria (CeO2-x) electrodes. The experiments reveal a transient build-up of surface intermediates (OH(-) and Ce(3+)) and show the separation of charge at the gas-solid interface exclusively in the electrochemically active region of the SOC. During water electrolysis on ceria, the increase in surface potentials of the adsorbed OH(-) and incorporated O(2-) differ by 0.25 eV in the active regions. For hydrogen electro-oxidation on ceria, the surface concentrations of OH(-) and O(2-) shift significantly from their equilibrium values. These data suggest that the same charge transfer step (H2O + Ce(3+) <-> Ce(4+) + OH(-) + H(•)) is rate limiting in both the forward (water electrolysis) and reverse (H2 electro-oxidation) reactions. This separation of potentials reflects an induced surface dipole layer on the ceria surface and represents the effective electrochemical double layer at a gas-solid interface. The in situ XPS data and DFT calculations show that the chemical origin of the OH(-)/O(2-) potential separation resides in the reduced polarization of the Ce-OH bond due to the increase of Ce(3+) on the electrode surface. These results provide a graphical illustration of the electrochemically driven surface charge transfer processes under relevant and nonultrahigh vacuum conditions. PMID:23822749

  14. Confinement of hydrogen at high pressure in carbon nanotubes

    DOEpatents

    Lassila, David H.; Bonner, Brian P.

    2011-12-13

    A high pressure hydrogen confinement apparatus according to one embodiment includes carbon nanotubes capped at one or both ends thereof with a hydrogen-permeable membrane to enable the high pressure confinement of hydrogen and release of the hydrogen therethrough. A hydrogen confinement apparatus according to another embodiment includes an array of multi-walled carbon nanotubes each having first and second ends, the second ends being capped with palladium (Pd) to enable the high pressure confinement of hydrogen and release of the hydrogen therethrough as a function of palladium temperature, wherein the array of carbon nanotubes is capable of storing hydrogen gas at a pressure of at least 1 GPa for greater than 24 hours. Additional apparatuses and methods are also presented.

  15. Hydrogen Embrittlement Evaluation in Tensile Properties of Stainless Steels at Cryogenic Temperatures

    NASA Astrophysics Data System (ADS)

    Ogata, T.

    2008-03-01

    The advanced design of fuel-cell vehicles requires high-pressure low-temperature hydrogen systems, which in turn requires a high-pressure low-temperature mechanical properties database to address hydrogen embrittlement issues. A very simple and safe mechanical properties testing procedure to evaluate low temperature hydrogen embrittlement has been developed and is reported here. Tensile properties of stainless steel, SUS 304, 304L and 316L, obtained by this simple method are in good agreement with previous data obtained in a high pressure chamber. The effect of hydrogen changed also with the amount of strain-induced martensitic transformation in those steels at low temperatures.

  16. Measurement of the Nickel/Nickel Oxide Phase Transition in High Temperature Hydrogenated Water Using the Contact Electric Resistance (CER) Technique

    SciTech Connect

    S.A. Attanasio; D.S. Morton; M.A. Ando; N.F. Panayotou; C.D. Thompson

    2001-05-08

    Prior studies of Alloy 600 and Alloy X-750 have shown the existence of a maximum in stress corrosion cracking (SCC) susceptibility in high temperature water (e.g., at 360 C), when testing is conducted over a range of dissolved (i.e., aqueous) hydrogen (H{sub 2}) concentrations. It has also been shown that this maximum in SCC susceptibility tends to occur in proximity to the nickel/nickel oxide (Ni/NiO) phase transition, suggesting that oxide phase stability may affect primary water SCC (PWSCC) resistance. Previous studies have estimated the Ni/NiO transition using thermodynamic calculations based on free energies of formation for NiO and H{sub 2}O. The present study reports experimental measurements of the Ni/NiO transition performed using a contact electric resistance (CER) instrument. The CER is capable of measuring the surface resistance of a metal to determine whether it is oxide-covered or oxide-free at a given condition. The transition aqueous hydrogen (H{sub 2}) concentration corresponding to the Ni/NiO equilibrium was measured at 288, 316, 338 and 360 C using high purity Ni specimens. The results showed an appreciable deviation (i.e., 7 to 58 scc H{sub 2}/kg H{sub 2}O) between the measured Ni/NiO transition and the theoretical Ni/NiO transition previously calculated using free energy data from the Journal of Solution Chemistry. The CER-measured position of the Ni/NiO transition is in good agreement with the maxima in PWSCC susceptibility at 338 and 360 C. The measured Ni/NiO transition provides a reasonable basis for estimating the aqueous H{sub 2} level at which the maximum in SCC susceptibility is likely to be observed at temperatures lower than 338 to 360 C, at which SCC tests are time-consuming to perform. Limited SCC data are presented which are consistent with the observation that SCC susceptibility is maximized near the Ni/NiO transition at 288 C.

  17. Facile fabrication of high-performance InGaZnO thin film transistor using hydrogen ion irradiation at room temperature

    SciTech Connect

    Ahn, Byung Du; Park, Jin-Seong; Chung, K. B.

    2014-10-20

    Device performance of InGaZnO (IGZO) thin film transistors (TFTs) are investigated as a function of hydrogen ion irradiation dose at room temperature. Field effect mobility is enhanced, and subthreshold gate swing is improved with the increase of hydrogen ion irradiation dose, and there is no thermal annealing. The electrical device performance is correlated with the electronic structure of IGZO films, such as chemical bonding states, features of the conduction band, and band edge states below the conduction band. The decrease of oxygen deficient bonding and the changes in electronic structure of the conduction band leads to the improvement of device performance in IGZO TFT with an increase of the hydrogen ion irradiation dose.

  18. High temperature furnace

    DOEpatents

    Borkowski, Casimer J.

    1976-08-03

    A high temperature furnace for use above 2000.degree.C is provided that features fast initial heating and low power consumption at the operating temperature. The cathode is initially heated by joule heating followed by electron emission heating at the operating temperature. The cathode is designed for routine large temperature excursions without being subjected to high thermal stresses. A further characteristic of the device is the elimination of any ceramic components from the high temperature zone of the furnace.

  19. Hydrogen Production by the Thermophilic Alga Mastigocladus laminosus: Effects of Nitrogen, Temperature, and Inhibition of Photosynthesis

    PubMed Central

    Miyamoto, Kazuhisa; Hallenbeck, Patrick C.; Benemann, John R.

    1979-01-01

    Hydrogen production by nitrogen-limited cultures of a thermophilic blue-green alga (cyanobacterium), Mastigocladus laminosus, was studied to develop the concept of a high-temperature biophotolysis system. Biophotolytic production of hydrogen by solar radiation was also demonstrated. Hydrogen consumption activity in these cultures was relatively high and is the present limiting factor on both the net rate and duration of hydrogen production. PMID:16345432

  20. High temperature hydrogen sulfide removal

    SciTech Connect

    Copeland, R.J.; Karpuk, M.E.

    1992-11-01

    The objective is to develop and test a regenerable stannic oxide-based sorbent to remove H{sub 2}S from hot coal gases while producing sulfur as the only product. The detailed technical objectives in support of this are: (1) Develop mechanically strong and chemically inert support materials which will retain their properties through multiple absorption regeneration cycles. (2) Develop mathematical models to predict the performance of large-scale systems from benchscale results. (3) Test the durability of the best sorbent/support combinations. (4) Conduct a bench-scale proof of concept test with the best stannic-oxide sorbent. Several approaches are being used to develop long-life sorbents. The investigators have tested sorbents produced by agglomeration, pressing, and extrusion. To date over 50 formulations have been tested, with several showing promise. Table II presents the results on five of these formulations; all of these formulations had surface areas in excess of 2 m{sup 2}/gm. All of the formulations meet the goals for porosity, tin content, and surface area. The crush strength for a 1/8inches dia. by 1/8inches long sorbent is significantly affected by the method of preparing the sorbent.

  1. Interaction-induced dipoles of hydrogen molecules colliding with helium atoms: a new ab initio dipole surface for high-temperature applications.

    PubMed

    Li, Xiaoping; Mandal, Anirban; Miliordos, Evangelos; Hunt, Katharine L C

    2012-01-28

    We report new ab initio results for the interaction-induced dipole moments Δμ of hydrogen molecules colliding with helium atoms. These results are needed in order to calculate collision-induced absorption spectra at high temperatures; applications include modeling the radiative profiles of very cool white dwarf stars, with temperatures from 3500 K to 9000 K. We have evaluated the dipoles based on finite-field calculations, with coupled cluster methods in MOLPRO 2006 and aug-cc-pV5Z (spdfg) basis sets for both the H and He centers. We have obtained values of Δμ for eight H(2) bond lengths ranging from 0.942 a.u. to 2.801 a.u., for 15 intermolecular separations R ranging from 2.0 a.u. to 10.0 a.u., and for 19 different relative orientations. In general, our values agree well with earlier ab initio results, for the geometrical configurations that are treated in common, but we have determined more points on the collision-induced dipole surface by an order of magnitude. These results make it possible to calculate transition probabilities for molecules in excited vibrational states, overtones, and rotational transitions with ΔJ > 4. We have cast our results in the symmetry-adapted form needed for absorption line shape calculations, by expressing Δμ as a series in the spherical harmonics of the orientation angles of the intermolecular vector and of a unit vector along the H(2) bond axis. The expansion coefficients depend on the H(2) bond length and the intermolecular distance R. For large separations R, we show that the ab initio values of the leading coefficients converge to the predictions from perturbation theory, including both classical multipole polarization and dispersion effects. PMID:22299884

  2. High-temperature diffusion of hydrogen, carbon monoxide, and carbon dioxide in liquid n-heptane, n-dodecane, and n-hexadecane

    SciTech Connect

    Matthews, M.A.; Rodden, J.B.; Akgerman, A.

    1987-07-01

    Mutual diffusion coefficients at infinite dilution have been measured for hydrogen, carbon monoxide, and carbon dioxide in the solvents n-heptane, n-dodecane, and n-hexadecane. The data cover the temperature range from 25 to 293/sup 0/C and pressures of 1415 and 3450 kPa. The Taylor dispersion method was used for diffusion measurements. It was found that the Sovova correlation for diffusion of dissolved gases in liquids failed to predict diffusivities at temperatures above ambient. A free-volume approach to correlation is indicated instead.

  3. Optical absorption measurements of hydrogen chloride at high temperature and high concentration in the presence of water using a tunable diode laser system for application in pyrohydrolysis non-ferrous industrial process control.

    PubMed

    Tzanetakis, Tommy; Susilo, Robin; Wang, Zhenyou; Padmanabhan, Arathi; Davis, Boyd R; Thomson, Murray J

    2015-06-01

    A tunable diode laser (TDL) was used to measure hydrogen chloride (HCl) spectra at 5747 cm(-1) (1.74 μm) and temperatures of 25-950 °C in a quartz cell. The purpose was to evaluate the capability of monitoring HCl concentration under pyrohydrolysis conditions using a near-infrared (NIR) laser. These conditions are characterized by 20-40% HCl, 2-40% H2O, and the presence of metal chloride vapors at temperatures of 600-1000 °C. Spectral peak area measurements of HCl-N2 mixtures at atmospheric pressure and a path length of 8.1 cm showed linear absorption behavior between concentrations of 5-95% and temperatures of 25-950 °C. Results from the addition of 2-40% water (H2O) indicate that the HCl peak area relationships are not affected for temperatures of 350-950 °C. Evaporating NiCl2 within the cell did not show spectral interference effects with HCl between 650 and 850 °C. The results from this work indicate that a near-infrared optical sensor is capable of measuring high HCl concentrations at high temperatures in the presence of high H2O content during pyrohydrolysis process conditions. PMID:26054333

  4. On the room-temperature phase diagram of high pressure hydrogen: an ab initio molecular dynamics perspective and a diffusion Monte Carlo study.

    PubMed

    Chen, Ji; Ren, Xinguo; Li, Xin-Zheng; Alfè, Dario; Wang, Enge

    2014-07-14

    The finite-temperature phase diagram of hydrogen in the region of phase IV and its neighborhood was studied using the ab initio molecular dynamics (MD) and the ab initio path-integral molecular dynamics (PIMD). The electronic structures were analyzed using the density-functional theory (DFT), the random-phase approximation, and the diffusion Monte Carlo (DMC) methods. Taking the state-of-the-art DMC results as benchmark, comparisons of the energy differences between structures generated from the MD and PIMD simulations, with molecular and dissociated hydrogens, respectively, in the weak molecular layers of phase IV, indicate that standard functionals in DFT tend to underestimate the dissociation barrier of the weak molecular layers in this mixed phase. Because of this underestimation, inclusion of the quantum nuclear effects (QNEs) in PIMD using electronic structures generated with these functionals leads to artificially dissociated hydrogen layers in phase IV and an error compensation between the neglect of QNEs and the deficiencies of these functionals in standard ab initio MD simulations exists. This analysis partly rationalizes why earlier ab initio MD simulations complement so well the experimental observations. The temperature and pressure dependencies for the stability of phase IV were also studied in the end and compared with earlier results. PMID:25028021

  5. On the room-temperature phase diagram of high pressure hydrogen: An ab initio molecular dynamics perspective and a diffusion Monte Carlo study

    SciTech Connect

    Chen, Ji; Ren, Xinguo; Li, Xin-Zheng; Alfè, Dario; Wang, Enge

    2014-07-14

    The finite-temperature phase diagram of hydrogen in the region of phase IV and its neighborhood was studied using the ab initio molecular dynamics (MD) and the ab initio path-integral molecular dynamics (PIMD). The electronic structures were analyzed using the density-functional theory (DFT), the random-phase approximation, and the diffusion Monte Carlo (DMC) methods. Taking the state-of-the-art DMC results as benchmark, comparisons of the energy differences between structures generated from the MD and PIMD simulations, with molecular and dissociated hydrogens, respectively, in the weak molecular layers of phase IV, indicate that standard functionals in DFT tend to underestimate the dissociation barrier of the weak molecular layers in this mixed phase. Because of this underestimation, inclusion of the quantum nuclear effects (QNEs) in PIMD using electronic structures generated with these functionals leads to artificially dissociated hydrogen layers in phase IV and an error compensation between the neglect of QNEs and the deficiencies of these functionals in standard ab initio MD simulations exists. This analysis partly rationalizes why earlier ab initio MD simulations complement so well the experimental observations. The temperature and pressure dependencies for the stability of phase IV were also studied in the end and compared with earlier results.

  6. High temperature sensor

    DOEpatents

    Tokarz, Richard D.

    1982-01-01

    A high temperature sensor includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1,000 to 2,000 K.). When required, the sensor can be encased within a ceramic protective coating.

  7. High-Pressure Studies of the Hydrogen Halides

    NASA Astrophysics Data System (ADS)

    Katz, Allen Israel

    This dissertation presents an experimental study of hydrogen bonding in the solid hydrogen halides under high pressure. The high pressures were obtained with a diamond-anvil high pressure cell. Raman scattering experiments were performed on hydrogen bromide and hydrogen fluoride under pressures up to 200 kilobars. Powder x-ray diffraction experiments were performed on hydrogen bromide under pressures up to 220 kilobars. All measurements were performed at low-temperature (approximately 20 Kelvin) in the ordered orthorhombic phase III consisting of planar zig-zag chains of hydrogen bonded molecules. In the x-ray measurements on hydrogen bromide, all three orthorhombic lattice parameters were measured. The out-of-plane c-lattice parameter decreased initially much faster than the b-lattice parameter which is in the direction of the zig-zag hydrogen bonded chains. This is expected due to the weak interchain forces as opposed to the much stronger hydrogen and molecular bond forces in the chain. Surprisingly, the a and b-lattice parameters have the same pressure dependence. Raman spectra were taken of both the high frequency molecular stretching modes and the lattice modes. The stretching mode frequencies of all three hydrogen halides decrease with increasing pressure, indicative of charge transfer out of the molecular bond and into the hydrogen bond. The stretching frequency of hydrogen fluoride was observed to decrease at the greatest rate with increasing pressure. In hydrogen bromide, the two lowest frequency librational modes crossed frequencies at about 50 kilobars. After this crossing, the lower frequency mode exhibited an unusual lack of pressure dependence and an unusually large intensity. The hydrogen fluoride lattice mode frequencies all appear flat with very little pressure dependence. The ambient temperature ruby pressure scale, used for all pressure measurements in this dissertation, was calibrated at 20 Kelvin by comparison to the equation -of-state for gold

  8. Mechanical properties of turbine blade alloys in hydrogen at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Deluca, D. P.

    1981-01-01

    The mechanical properties of single crystal turbine blade alloys in a gaseous hydrogen environment were determined. These alloys are proposed for use in space propulsion systems in pure or partial high pressure hydrogen environments at elevated temperatures. Mechanical property tests included: tensile, creep, low fatigue (LCF), and crack growth. Specimens were in both transverse and longitudinal directions relative to the casting solidification direction. Testing was conducted on solid specimens exposed to externally pressurized environments of gaseous hydrogen and hydrogen-enriched steam.

  9. Hydrogen Environment Embrittlement on Austenitic Stainless Steels from Room Temperature to Low Temperatures

    NASA Astrophysics Data System (ADS)

    Ogata, Toshio

    2015-12-01

    Hydrogen environment embrittlement (HEE) on austenitic stainless steels SUS304, 304L, and 316L in the high pressure hydrogen gas was evaluated from ambient temperature to 20 K using a very simple mechanical properties testing procedure. In the method, the high- pressure hydrogen environment is produced just inside the hole in the specimen and the specimen is cooled in a cooled-alcohol dewar and a cryostat with a GM refrigerator. The effect of HEE was observed in tensile properties, especially at lower temperatures, and fatigue properties at higher stress level but almost no effect around the stress level of yield strength where almost no strain-induced martensite was produced. So, no effect of HEE on austenitic stainless steels unless the amount of the ferrite phase is small.

  10. Sum frequency generation vibrational spectroscopy studies of adsorbates on Pt(111): Studies of CO at high pressures and temperatures, coadsorbed with olefins and its role as a poison in ethylene hydrogenation

    SciTech Connect

    Kung, Kyle Yi

    2000-12-31

    High pressure high temperature CO adsorption and coadsorption with ethylene and propylene on Pt(111) was monitored in situ with infrared-visible sum frequency generation (SFG). At high pressures and high temperatures, CO dissociates on a Pt(111) surface to form carbon. At 400 torr CO pressure and 673K, CO modifies the Pt(111) surface through a carbonyl intermediate, and dissociates to leave carbon on the surface. SFG was used to follow the CO peak evolution from monolayer adsorption in ultra high vacuum (UHV) to 400 torr CO pressure. At this high pressure, a temperature dependence study from room temperature to 823K was carried out. Auger electron spectroscopy was used to identify carbon on the surface CO coadsorption with ethylene and CO coadsorption with propylene studies were carried out with 2-IR 1-visible SFG. With this setup, two spectral ranges covering the C-H stretch range and the CO stretch range can be monitored simultaneously. The coadsorption study with ethylene reveals that after 5L ethylene exposure on a Pt(111) surface to form ethylidyne , CO at high pressures cannot completely displace the ethylidyne from the surface. Instead, CO first adsorbs on defect sites at low pressures and then competes with ethylidyne for terrace sites at high pressures. Propylene coadsorption with CO at similar conditions shows that propylidyne undergoes conformation changes with increased CO pressure and at 1 torr, is absent from the Pt(111) surface. Experiments on CO poisoning of ethylene hydrogenation was carried by 2-IR 1-visible SFG. At 1 torr CO,10 torr ethylene and 100 torr hydrogen, CO was found to block active sites necessary for ethylene hydrogenation, Above 425K, CO desorbs from the surface to allow ethylene hydrogenation to occur. The gas phase species were monitored by gas chromatography.

  11. Low temperature, low pressure hydrogen gettering

    DOEpatents

    Anderson, D.R.; Courtney, R.L.; Harrah, L.A.

    1975-07-22

    A system is described for the gettering of hydrogen and its isotopes. The gettering materials are painted or coated onto, or otherwise disposed in an area or volume from which hydrogen is to be removed. (auth)

  12. Mixture including hydrogen and hydrocarbon having pressure-temperature stability

    NASA Technical Reports Server (NTRS)

    Mao, Wendy L. (Inventor); Mao, Ho-Kwang (Inventor)

    2009-01-01

    The invention relates to a method of storing hydrogen that employs a mixture of hydrogen and a hydrocarbon that can both be used as fuel. In one embodiment, the method involves maintaining a mixture including hydrogen and a hydrocarbon in the solid state at ambient pressure and a temperature in excess of about 10 K.

  13. High temperature refrigerator

    DOEpatents

    Steyert, Jr., William A.

    1978-01-01

    A high temperature magnetic refrigerator which uses a Stirling-like cycle in which rotating magnetic working material is heated in zero field and adiabatically magnetized, cooled in high field, then adiabatically demagnetized. During this cycle said working material is in heat exchange with a pumped fluid which absorbs heat from a low temperature heat source and deposits heat in a high temperature reservoir. The magnetic refrigeration cycle operates at an efficiency 70% of Carnot.

  14. High-Temperature Superconductivity

    NASA Astrophysics Data System (ADS)

    Tanaka, Shoji

    2006-12-01

    A general review on high-temperature superconductivity was made. After prehistoric view and the process of discovery were stated, the special features of high-temperature superconductors were explained from the materials side and the physical properties side. The present status on applications of high-temperature superconductors were explained on superconducting tapes, electric power cables, magnets for maglev trains, electric motors, superconducting quantum interference device (SQUID) and single flux quantum (SFQ) devices and circuits.

  15. High temperature measuring device

    DOEpatents

    Tokarz, Richard D.

    1983-01-01

    A temperature measuring device for very high design temperatures (to 2,000.degree. C.). The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells. The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensionally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured. Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions.

  16. Probing Hydrogen Diffusion under High Pressure

    NASA Astrophysics Data System (ADS)

    Bove, L. E.; Klotz, S.; Strassle, T.; Saitta, M.

    2012-12-01

    The study of the microscopic mechanism governing hydrogen and hydrogen-based liquids (as water, ammonia and methane) diffusion is crucial for a variety of scientific issues spanning most of natural sciences. As an example, characterizing hydrogen diffusion in a confined medium, like in porous systems or zeolites, is fundamental in problems relating to environment, hydrogen storage and industrial applications [1]. The presence of water diffusion in the minerals of the Earth's mantle have strong incidence on the processes governing volcanic eruptions and intermediate-depth seismicity. As last example, knowing in details the microscopic dynamics of hydrogen-based simple liquids under extreme conditions is essential in order to interpret observations and develop models of planet interiors [2]. On the other hand, water and other simple hydrogen-based liquids have always been key systems in the development of modern condensed-matter physics, because of their simple electronic structure and the peculiar properties deriving from the hydrogen-bond network. Their high compressibility and chemical reactivity have made these systems very challenging to study experimentally under static high P-T conditions. In the last few years, a large effort has been undertaken by several groups around the world [2] to extend the static and dynamic techniques to high temperatures and pressures, a program in which our group has been actively involved [3-6]. However, while the structure of water and other hydrogenated liquids of geological interest, is now known up to almost 20 GPa, the study of their transport properties greatly lags behind. We have recently developed a new large-volume gasket-anvil ensemble for the Paris-Edinburgh press based on a novel toroidal design [7], which allows to perform quasi elastic neutron scattering measurements on hydrogen based liquids up to one order of magnitude higher pressures (5 GPa) respect to what was achievable with standard methods [8]. The large

  17. Fabrication method for a room temperature hydrogen sensor

    NASA Technical Reports Server (NTRS)

    Seal, Sudipta (Inventor); Shukla, Satyajit V. (Inventor); Ludwig, Lawrence (Inventor); Cho, Hyoung (Inventor)

    2011-01-01

    A sensor for selectively determining the presence and measuring the amount of hydrogen in the vicinity of the sensor. The sensor comprises a MEMS device coated with a nanostructured thin film of indium oxide doped tin oxide with an over layer of nanostructured barium cerate with platinum catalyst nanoparticles. Initial exposure to a UV light source, at room temperature, causes burning of organic residues present on the sensor surface and provides a clean surface for sensing hydrogen at room temperature. A giant room temperature hydrogen sensitivity is observed after making the UV source off. The hydrogen sensor of the invention can be usefully employed for the detection of hydrogen in an environment susceptible to the incursion or generation of hydrogen and may be conveniently used at room temperature.

  18. High-temperature sensor

    DOEpatents

    Not Available

    1981-01-29

    A high temperature sensor is described which includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1000 to 2000/sup 0/K). When required, the sensor can be encased within a ceramic protective coating.

  19. Grain boundary depletion and migration during selective oxidation of Cr in a Ni-5Cr binary alloy exposed to high-temperature hydrogenated water

    SciTech Connect

    Schreiber, Daniel K.; Olszta, Matthew J.; Bruemmer, Stephen M.

    2014-10-01

    High-resolution microscopy of a high-purity Ni-5Cr alloy exposed to 360°C hydrogenated water reveals intergranular selective oxidation of Cr accompanied by local Cr depletion and diffusion-induced grain boundary migration (DIGM). The corrosion-product oxide consists of a porous, interconnected network of Cr2O3 platelets with no further O ingress into the metal ahead. Extensive grain boundary depletion of Cr (to <0.05at.%) is observed typically 20–100 nm wide as a result of DIGM and reaching depths of many micrometers beyond the oxidation front.

  20. Monitoring the hydrogen distribution in poly(2,5-benzimidazole)-based (ABPBI) membranes in operating high-temperature polymer electrolyte fuel cells by using H-D contrast neutron imaging

    NASA Astrophysics Data System (ADS)

    Arlt, Tobias; Lüke, Wiebke; Kardjilov, Nikolay; Banhart, John; Lehnert, Werner; Manke, Ingo

    2015-12-01

    Neutron imaging in combination with the deuterium contrast method was used to analyze the hydrogen distribution and exchange processes in a high-temperature polymer electrolyte fuel cell in-operando. While operating the cell at steady state conditions at 200 mA cm-2 and λan/ca = 2/2, changeovers of the anode feed gases between hydrogen (H2) and deuterium were analyzed by neutron radiography. Proton-deuterium exchange times and progresses were studied in-operando. The exchange of protons by deuterons proceeds much faster (approx. 108-138 s) than the exchange of deuterons by protons (approx. 144-174 s), whereby the exchange takes place first near the gas inlet while a delayed onset was observed near the outlet. We can explain this effect by the different diffusion coefficients and atomic masses of deuterium and hydrogen and the operating conditions of the cell.

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

    DOEpatents

    Lueking, Angela; Narayanan, Deepa

    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. Thermal coupling of protons and neutral hydrogen with anisotropic temperatures in the fast solar wind

    NASA Astrophysics Data System (ADS)

    Allen, Lorraine A.; Habbal, Shadia R.; Li, Xing

    2000-10-01

    The thermal coupling between the neutral hydrogen and protons in the inner corona is explored by extending the study of Allenet al. [1998] to include anisotropic proton temperature to determine what the neutral hydrogen Ly α spectral line measurements reveal about the proton temperature, temperature anisotropy, and outflow velocity in the fast solar wind. The anisotropic proton temperature is produced by ion cyclotron resonant interaction of protons with high-frequency waves, produced by a nonlinear cascade at the Kolmogorov dissipation rate from dominant lower-frequency Alfvén waves. As a result of the coupling between the respective parallel and perpendicular components of the neutral hydrogen and proton temperatures, a greater temperature anisotropy in the neutral hydrogen develops as compared to the case when the proton temperature is isotropic. The neutral hydrogen and proton effective temperatures (Teff), incorporating both random and wave motions of the particles, and outflow velocities, are comparable below ~3Rs. Neutral hydrogen anisotropy ratios, TH(eff)/T∥, ~4 below 3Rs are readily attained, in agreement with observations. Below ~3Rs, these reflect the proton anisotropy ratio. For plasma conditions typical of the fast solar wind, these results imply that the measured Ly α spectral line profiles, from which the neutral hydrogen temperature, anisotropy ratio, and outflow velocity are inferred, are equivalent to measurements of protons below ~3Rs. Beyond this distance the width of the measured Ly α spectral lines provides a lower limit to the proton effective temperature and temperature anisotropy in the inner corona.

  3. Hydrogen Storage at Ambient Temperature by the Spillover Mechanism

    SciTech Connect

    Yang , Ralph T.

    2011-02-04

    The goal of this project was to develop new nanostructured sorbent materials, using the hydrogen spillover mechanism that could meet the DOE 2010 system targets for on-board vehicle hydrogen storage. Hydrogen spillover may be broadly defined as the transport (i.e., via surface diffusion) of dissociated hydrogen adsorbed or formed on a first surface onto another surface. The first surface is typically a metal (that dissociates H2) and the second surface is typically the support on which the metal is doped. Hydrogen spillover is a well documented phenomenon in the catalysis literature, and has been known in the catalysis community for over four decades, although it is still not well understood.1, 2 Much evidence has been shown in the literature on its roles played in catalytic reactions. Very little has been studied on hydrogen storage by spillover at ambient temperature. However, it is also known to occur at such temperature, e.g., direct evidence has been shown for spillover on commercial fuel-cell, highly dispersed Pt/C, Ru/C and PtRu/C catalysts by inelastic neutron scattering.3 To exploit spillover for storage, among the key questions are whether spillover is reversible at ambient temperature and if the adsorption (refill) and desorption rates at ambient temperature are fast enough for automotive applications. In this project, we explored new sorbents by using a transition metal (e.g., Pt, Ru, Pd and Ni) as the H2 dissociation source and sorbents as the hydrogen receptor. The receptors included superactivated carbons (AX-21 and Maxsorb), metal organic frameworks (MOFs) and zeolites. Different metal doping methods have been used successfully to achieve high metal dispersion thereby allowing significant spillover enhancements, as well as a bridging technique used for bridging to MOFs. Among the metals tested, Pt is the hardest to achieve high metal dispersion (and consequently spillover) while Ru is the easiest to disperse. By properly dispersing Pt on

  4. High-Pressure Multi-Mbar Conductivity Experiments on Hydrogen: The Quest for Solid Metallic Hydrogen

    SciTech Connect

    Jackson, D

    2007-02-07

    Ultra-dense hydrogen has long been the subject of intense experimental and theoretical research due to the fascinating physics which arises from this supposedly simple system. The properties of ultra-dense hydrogen also have important implications for planetary physics, since the interiors of the giant planets Jupiter and Saturn are believed to consist of cores of dense, metallic hydrogen. Finally, ultra-dense hydrogen is of direct programmatic interest, and multiple-shock compression experiments on hydrogen to the metallic state have stimulated the accelerated development of new hydrogen equation-of-state (EOS) models used for ICF and other applications. The focus of our research has often been described as the ''Holy Grail'' of high-pressure physics research: The metallization of solid hydrogen. Metallic hydrogen has long been considered to be the prototypical system for the study of insulator-to-metal (I-M) transitions. Although metallic hydrogen (Z=1) may superficially appear to be a very simple material, it is in fact an extremely challenging system for theoretical analysis due to the presence of large zero-point atomic motions and the complete absence of any core electrons. Thus, solid metallic hydrogen promises to be a fascinating material. Among its predicted properties is the possibility of being a high temperature superconductor with a critical temperature T{sub c} of the order of {approx} 100K [1]. The successful metallization of solid hydrogen would be a groundbreaking scientific discovery and open up new frontiers in science and possibly technology as well.

  5. High-Temperature Superconductivity

    SciTech Connect

    Peter Johnson

    2008-11-05

    Like astronomers tweaking images to gain a more detailed glimpse of distant stars, physicists at Brookhaven National Laboratory have found ways to sharpen images of the energy spectra in high-temperature superconductors — materials that carry electrical c

  6. High-Temperature Superconductivity

    ScienceCinema

    Peter Johnson

    2010-01-08

    Like astronomers tweaking images to gain a more detailed glimpse of distant stars, physicists at Brookhaven National Laboratory have found ways to sharpen images of the energy spectra in high-temperature superconductors ? materials that carry electrical c

  7. Metal-Hydrogen Phase Diagrams in the Vicinity of Melting Temperatures

    SciTech Connect

    Shapovalov, V.I.

    1999-01-06

    Hydrogen-metal interaction phenomena belong to the most exciting challenges of today's physical metallurgy and physics of solids due to the uncommon behavior of hydrogen in condensed media and to the need for understanding hydrogen's strong negative impact on properties of some high-strength steels and.alloys. The paper cites and summarizes research data on fundamental thermodynamic characteristics of hydrogen in some metals that absorb it endothermally at elevated temperatures. For a number of metal-hydrogen systems, information on some phase diagrams previously not available to the English-speaking scientific community is presented.

  8. Reaction kinetics for the oxygen hydrogenation process on Pt(111) derived from temperature-programmed XPS

    NASA Astrophysics Data System (ADS)

    Näslund, Lars-Åke

    2013-12-01

    Oxygen hydrogenation under ultra high vacuum conditions at the platinum surface was explored using temperature-programmed X-ray photoelectron spectroscopy. Through modeling of the oxygen consumption, information on the reaction kinetics was obtained indicating that the reaction rate of the oxygen hydrogenation process depends on the hydrogen diffusion and on the lifetime of hydroxyl intermediates. The reaction rate is, however, enhanced when an autocatalytic process stabilizes the hydroxyl intermediates through hydrogen bonding to neighboring water molecules. The overall activation energy for the hydrogenation of atomic oxygen to form water was determined to be 0.20 eV with a frequency factor of only 103 s- 1.

  9. Measurement component technology. Volume 1: Cryogenic pressure measurement technology, high pressure flange seals, hydrogen embrittlement of pressure transducer material, close coupled versus remote transducer installation and temperature compensation of pressure transducers

    NASA Technical Reports Server (NTRS)

    Hayakawa, K. K.; Udell, D. R.; Iwata, M. M.; Lytle, C. F.; Chrisco, R. M.; Greenough, C. S.; Walling, J. A.

    1972-01-01

    The results are presented of an investigation into the availability and performance capability of measurement components in the area of cryogenic temperature, pressure, flow and liquid detection components and high temperature strain gages. In addition, technical subjects allied to the components were researched and discussed. These selected areas of investigation were: (1) high pressure flange seals, (2) hydrogen embrittlement of pressure transducer diaphragms, (3) The effects of close-coupled versus remote transducer installation on pressure measurement, (4) temperature transducer configuration effects on measurements, and (5) techniques in temperature compensation of strain gage pressure transducers. The purpose of the program was to investigate the latest design and application techniques in measurement component technology and to document this information along with recommendations for upgrading measurement component designs for future S-2 derivative applications. Recommendations are provided for upgrading existing state-of-the-art in component design, where required, to satisfy performance requirements of S-2 derivative vehicles.

  10. High Temperature Capacitor Development

    SciTech Connect

    John Kosek

    2009-06-30

    The absence of high-temperature electronics is an obstacle to the development of untapped energy resources (deep oil, gas and geothermal). US natural gas consumption is projected to grow from 22 trillion cubic feet per year (tcf) in 1999 to 34 tcf in 2020. Cumulatively this is 607 tcf of consumption by 2020, while recoverable reserves using current technology are 177 tcf. A significant portion of this shortfall may be met by tapping deep gas reservoirs. Tapping these reservoirs represents a significant technical challenge. At these depths, temperatures and pressures are very high and may require penetrating very hard rock. Logistics of supporting 6.1 km (20,000 ft) drill strings and the drilling processes are complex and expensive. At these depths up to 50% of the total drilling cost may be in the last 10% of the well depth. Thus, as wells go deeper it is increasingly important that drillers are able to monitor conditions down-hole such as temperature, pressure, heading, etc. Commercial off-the-shelf electronics are not specified to meet these operating conditions. This is due to problems associated with all aspects of the electronics including the resistors and capacitors. With respect to capacitors, increasing temperature often significantly changes capacitance because of the strong temperature dependence of the dielectric constant. Higher temperatures also affect the equivalent series resistance (ESR). High-temperature capacitors usually have low capacitance values because of these dielectric effects and because packages are kept small to prevent mechanical breakage caused by thermal stresses. Electrolytic capacitors do not operate at temperatures above 150oC due to dielectric breakdown. The development of high-temperature capacitors to be used in a high-pressure high-temperature (HPHT) drilling environment was investigated. These capacitors were based on a previously developed high-voltage hybridized capacitor developed at Giner, Inc. in conjunction with a

  11. High temperature pressure gauge

    DOEpatents

    Echtler, J. Paul; Scandrol, Roy O.

    1981-01-01

    A high temperature pressure gauge comprising a pressure gauge positioned in fluid communication with one end of a conduit which has a diaphragm mounted in its other end. The conduit is filled with a low melting metal alloy above the diaphragm for a portion of its length with a high temperature fluid being positioned in the remaining length of the conduit and in the pressure gauge.

  12. High-temperature electronics

    NASA Technical Reports Server (NTRS)

    Matus, Lawrence G.; Seng, Gary T.

    1990-01-01

    To meet the needs of the aerospace propulsion and space power communities, the high temperature electronics program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. This program supports a major element of the Center's mission - to perform basic and developmental research aimed at improving aerospace propulsion systems. Research is focused on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of SiC devices.

  13. High-temperature electronics

    NASA Astrophysics Data System (ADS)

    Matus, Lawrence G.; Seng, Gary T.

    1990-02-01

    To meet the needs of the aerospace propulsion and space power communities, the high temperature electronics program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. This program supports a major element of the Center's mission - to perform basic and developmental research aimed at improving aerospace propulsion systems. Research is focused on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of SiC devices.

  14. High temperature electronics

    NASA Astrophysics Data System (ADS)

    Seng, Gary T.

    1991-03-01

    In recent years, the aerospace propulsion and space power communities have acknowledged a growing need for electronic devices that are capable of sustained high-temperature operation. Aeropropulsion applications for high-temperature electronic devices include engine ground test instrumentation such as multiplexers, analog-to-digital converters, and telemetry systems capable of withstanding hot section engine temperatures in excess of 600 C. Uncooled operation of control and condition monitoring systems in advanced supersonic aircraft would subject the electronics to temperatures in excess of 300 C. Similarly, engine-mounted integrated electronic sensors could reach temperatures which exceed 500 C. In addition to aeronautics, there are many other areas that could benefit from the existence of high-temperature electronic devices. Space applications include power electronic devices for space platforms and satellites. Since power electronics require radiators to shed waste heat, electronic devices that operate at higher temperatures would allow a reduction in radiator size. Terrestrial applications include deep-well drilling instrumentation, high power electronics, and nuclear reactor instrumentation and control. To meet the needs of the applications mentioned previously, the high-temperature electronics (HTE) program at the Lewis Research Center is developing silicon carbide (SiC) as a high-temperature semiconductor material. Research is focused on developing the crystal growth, growth modeling, characterization, and device fabrication technologies necessary to produce a family of SiC devices. Interest in SiC has grown dramatically in recent years due to solid advances in the technology. Much research remains to be performed, but SiC appears ready to emerge as a useful semiconductor material.

  15. High temperature structural silicides

    SciTech Connect

    Petrovic, J.J.

    1997-03-01

    Structural silicides have important high temperature applications in oxidizing and aggressive environments. Most prominent are MoSi{sub 2}-based materials, which are borderline ceramic-intermetallic compounds. MoSi{sub 2} single crystals exhibit macroscopic compressive ductility at temperatures below room temperature in some orientations. Polycrystalline MoSi{sub 2} possesses elevated temperature creep behavior which is highly sensitive to grain size. MoSi{sub 2}-Si{sub 3}N{sub 4} composites show an important combination of oxidation resistance, creep resistance, and low temperature fracture toughness. Current potential applications of MoSi{sub 2}-based materials include furnace heating elements, molten metal lances, industrial gas burners, aerospace turbine engine components, diesel engine glow plugs, and materials for glass processing.

  16. High temperature probe

    DOEpatents

    Swan, Raymond A.

    1994-01-01

    A high temperature probe for sampling, for example, smokestack fumes, and is able to withstand temperatures of 3000.degree. F. The probe is constructed so as to prevent leakage via the seal by placing the seal inside the water jacket whereby the seal is not exposed to high temperature, which destroys the seal. The sample inlet of the probe is also provided with cooling fins about the area of the seal to provide additional cooling to prevent the seal from being destroyed. Also, a heated jacket is provided for maintaining the temperature of the gas being tested as it passes through the probe. The probe includes pressure sensing means for determining the flow velocity of an efficient being sampled. In addition, thermocouples are located in various places on the probe to monitor the temperature of the gas passing there through.

  17. High Temperature ESP Monitoring

    SciTech Connect

    Jack Booker; Brindesh Dhruva

    2011-06-20

    The objective of the High Temperature ESP Monitoring project was to develop a downhole monitoring system to be used in wells with bottom hole well temperatures up to 300°C for measuring motor temperature, formation pressure, and formation temperature. These measurements are used to monitor the health of the ESP motor, to track the downhole operating conditions, and to optimize the pump operation. A 220 ºC based High Temperature ESP Monitoring system was commercially released for sale with Schlumberger ESP motors April of 2011 and a 250 ºC system with will be commercially released at the end of Q2 2011. The measurement system is now fully qualified, except for the sensor, at 300 °C.

  18. High resolution Holocene temperature records for the northeastern United States from hydrogen isotope ratios of mid-chain aquatic plant lipids

    NASA Astrophysics Data System (ADS)

    Gao, L.; Huang, Y.; Hou, J.; Shuman, B. N.; Oswald, W.; Foster, D. R.

    2011-12-01

    Holocene temperature changes for the northeastern U.S. are poorly defined due to the lack of suitable proxies. We developed a mathematic model to quantify the percentage contribution of aquatic plants to the mid-chain n-alkyl lipids in lake sediments (Gao et al., GCA, 2011). We show that Little Pond in Royalston, Massachusetts is characterized by exceptionally high percentages (>90%) of aquatic contribution to the mid-chain n-alkyl lipids in sediments, and generated a quantitative, high-resolution Holocene temperature record based on compound-specific D/H ratio of behenic acid (δDBA) (Figure). Our record shows that the Laurentide Ice Sheet suppressed the regional temperature by ~ 2 °C during the early Holocene. Numerous rapid and large (~4.9 °C) climate oscillations occurred as a result of major freshwater outbursts and the resulting changes in North Atlantic meridional overturning circulation. Following a major climate reversal at 8.2 ka, the regional climatic optimum occurred between ~8 ka and ~7 ka BP. Temperature gradually declined from ~8ka toward present by ~3.9 °C associated with the declining summer insolation. During the past two millennia, temperature changes closely mimic the synthesized borehole temperatures, with a temperature trough at ~1.8 ka and a peak at ~0.5 ka. Regional temperature does not show the typical little ice age trends, except a minimal temperature (~7 °C) at ~1850 A.D, which is followed by rapid temperature rise probably as a result of anthropogenic forcing. Combined with our previous data from Blood Pond, we have obtained centennial scale temperature history for the New England region for the past 15000 years.

  19. High temperature electronics technology

    NASA Astrophysics Data System (ADS)

    Dening, J. C.; Hurtle, D. E.

    1984-03-01

    This report summarizes the barrier metallization developments accomplished in a program intended to develop 300 C electronic controls capability for potential on-engine aircraft engine application. In addition, this report documents preliminary life test results at 300 C and above and discusses improved design practices required for high temperature integrated injection logic semiconductors. Previous Phase 1 activities focused on determining the viability of operating silicon semiconductor devices over the -55 C to +300 C temperature range. This feasibility was substantiated but the need for additional design work and process development was indicated. Phase 2 emphasized the development of a high temperature metallization system as the primary development need for high temperature silicon semiconductor applications.

  20. KINETIC EVIDENCE FOR THE FORMATION OF DISCRETE 1,4-DEHYDROBENZENE INTERMEDIATES. TRAPPING BY INTER- AND INTRAMOLECULAR HYDROGEN ATOM TRANSFER AND OBSERVATION OF HIGH-TEMPERATURE CIDNP

    SciTech Connect

    Lockhart, Thomas P.; Comita, Paul B.; Bergman, Robert C.

    1980-09-01

    Upon heating, alkyl substituted cis 1,2-diethynyl olefins under cyclization to yield reactive 1,4-dehydrobenzenes; the products isolated may be derived from either unimolecular or bimolecular reactions of the intermediate. Z-4,5-Diethynyl-4-octene (4) undergoes rearrangement to yield 2,3-di-n-propyl-1,4-dehydrobenzene (17). Solution pyrolysis of 4 in inert aromatic solvents produces three unimolecular products, Z-dodeca-4,8-diyn-6-ene (7), benzocyclooctene (9) and o-allyl-n-propylbenzene (10) in high yield. When 1,4-cyclohexadiene is added to the pyrolysis solution as a trapping agent, high yields of the reduced product o-di-n-propylbenzene (12) are obtained. The kinetics of solution pyrolysis of 4 in the presence and absence of trapping agent establish that 2,3-di-n-propyl-1,4-dehydrobenzene is a discrete intermediate on the pathway leading to products. When the reaction was run in the heated probe of an NMR spectrometer, CIDNP was observed in 10. This observation, along with kinetic and chemical trapping evidence, indicates the presence of two additional intermediates, formed from 17 by sequential intramolecular [1,5] hydrogen transfer, on the pathway to products. The observation of CIDNP, coupled with the reactivity exhibited by 17 and the other two intermediates, implicate a biradical description of these molecules. Biradical 17 has been estimated to have a lifetime of about 10{sup -9} sec at: 200°C and to lie in a well of kcal/mol with respect to the lowest energy unimolecular pathway ([1,5] hydrogen transfer). Ring opening (expected to be the lowest energy process for 1,4-dehydrobenzenes in which intramolecular hydrogen transfer is unlikely) to the isomeric diethynyl olefin 7 appears to have an activation enthalpy of about 10 kcal/moL Upon thermal reaction in the gas phase (400°C) or in solution in inert solvents Z-hexa-2,3-diethyl-1,5-~diyn-3-ene (5) rearranges in good yield to the isomeric diethynyl olefin Z-deca-3,7-diyn-5-ene (8) again presumably via 2

  1. Effect of hydrogen on the {beta} transus temperature of TC21 alloy

    SciTech Connect

    Zhu, T.K. Li, M.Q.

    2011-09-15

    Effect of hydrogen on the {beta} transus temperature of TC21 alloy was investigated by metallographic technique and dilatometry. It is found that the {beta} transus temperature is closely related to the hydrogen content. For the hydrogenated TC21 alloy, the starting and finishing temperatures of {alpha} {yields} {beta} phase transition decrease with the increasing of hydrogen content before the hydride precipitates. And the finishing temperature of {alpha} {yields} {beta} phase transition increases as the hydrogen content increases after the hydride precipitates. Furthermore, corresponding inherent mechanisms of the above-mentioned phenomena have been presented according to atomic diffusivity, interface migration and the precipitation of hydride. - Research Highlights: {yields} The {beta} transus temperature of TC21 alloy is closely related to hydrogen content. {yields} The mechanism for effect of hydrogen on the {beta} transus temperature is presented. {yields} Precipitation of hydride has a significant influence on the {beta} transus temperature. {yields} The {alpha}/{beta} interface migration has an important effect on the {beta} transus temperature. {yields} The improvement of atom diffusivity affects the {beta} transus temperature highly.

  2. Hydrogen Absorption into Austenitic Stainless Steels Under High-Pressure Gaseous Hydrogen and Cathodic Charge in Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Enomoto, Masato; Cheng, Lin; Mizuno, Hiroyuki; Watanabe, Yoshinori; Omura, Tomohiko; Sakai, Jun'ichi; Yokoyama, Ken'ichi; Suzuki, Hiroshi; Okuma, Ryuji

    2014-12-01

    Type 316L and Type 304 austenitic stainless steels, both deformed and non-deformed, were hydrogen charged cathodically in an aqueous solution as well as by exposure to high-pressure gaseous hydrogen in an attempt to identify suitable conditions of cathodic charge for simulating hydrogen absorption from gaseous hydrogen environments. Thermal desorption analysis (TDA) was conducted, and the amount of absorbed hydrogen and the spectrum shape were compared between the two charging methods. Simulations were performed by means of the McNabb-Foster model to analyze the spectrum shape and peak temperature, and understand the effects of deformation on the spectra. It was revealed that the spectrum shape and peak temperature were dependent directly upon the initial distribution of hydrogen within the specimen, which varied widely according to the hydrogen charge condition. Deformation also had a marked effect on the amount of absorbed hydrogen in Type 304 steel due to the strain-induced martensitic transformation.

  3. Comparative Spectroscopic Temperature Measurements In Hydrogen Hollow Cathode Glow Discharge

    NASA Astrophysics Data System (ADS)

    Majstorovic, G. Lj.; Šišovic, N. M.; Konjevic, N.

    2010-07-01

    We report results of optical emission spectroscopy measurements of rotational Trot and translational temperature Ttr of hydrogen molecules. The light source was hollow cathode glow discharge with titanium cathode operated in hydrogen at low pressure. The rotational temperature of excited electronic states of H2 was determined either from relative line intensities of the R branch of the GK ? B band or from the Q branch of the Fulcher-a diagonal band. The population of excited energy levels, determined from relative line intensities, was used to derive ro-vibronic temperature of the ground state of hydrogen molecule.

  4. High Temperature Piezoelectric Drill

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom; Zhang, Shujun

    2009-01-01

    The current NASA Decadal mission planning effort has identified Venus as a significant scientific target for a surface in-situ sampling/analyzing mission. The Venus environment represents several extremes including high temperature (460 deg C), high pressure (9 MPa), and potentially corrosive (condensed sulfuric acid droplets that adhere to surfaces during entry) environments. This technology challenge requires new rock sampling tools for these extreme conditions. Piezoelectric materials can potentially operate over a wide temperature range. Single crystals, like LiNbO3, have a Curie temperature that is higher than 1000 deg C and the piezoelectric ceramics Bismuth Titanate higher than 600 deg C. A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to 500 deg C was conducted. The study includes the high temperature properties investigations of engineering materials and piezoelectric ceramics with different formulas and doping. The drilling performances of a prototype Ultrasonic/Sonic Drill/Corer (USDC) using high temperate piezoelectric ceramics and single crystal were tested at temperature up to 500 deg C. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper.

  5. High-Temperature Lubricants

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In the early 1980's, Lewis Research Center began a program to develop high-temperature lubricants for use on future aircraft flying at three or more times the speed of sound, which can result in vehicle skin temperatures as high as 1,600 degrees Fahrenheit. A material that emerged from this research is a plasma-sprayed, self-lubricating metal- glass-fluoride coating able to reduce oxidation at very high temperatures. Technology is now in commercial use under the trade name Surf-Kote C-800, marketed by Hohman Plating and Manufacturing Inc. and manufactured under a patent license from NASA. Among its uses are lubrication for sliding contact bearings, shaft seals for turbopumps, piston rings for high performance compressors and hot glass processing machinery; it is also widely used in missile and space applications.

  6. High temperature hydraulic seals

    NASA Astrophysics Data System (ADS)

    Williams, K. R.

    1993-05-01

    This program investigated and evaluated high temperature hydraulic sealing technology, including seals, fluids, and actuator materials. Test limits for fluid pressure and temperature were 8000 psi and 700 F respectively. The original plan to investigate CTFE fluid at 350 F as well as other fluids at higher temperatures was reduced in scope to include only the higher temperature investigation. Seals were obtained from 11 manufacturers. Design requirements including materials, dimensions, clearances, and tolerances were established and test modules were constructed from the detail designs which were produced. Nine piston seals and one rod seal were tested at temperatures ranging from -65 to +600 F and pressures to 6000 psi. Fluid performance under these conditions was evaluated. Details of this activity and results of the effort are summarized in this report.

  7. Hydrogen storage on high-surface-area carbon monoliths for Adsorb hydrogen Gas Vehicle

    NASA Astrophysics Data System (ADS)

    Soo, Yuchoong; Pfeifer, Peter

    2014-03-01

    Carbon briquetting can increase hydrogen volumetric storage capacity by reducing the useless void volume resulting in a better packing density. It is a robust and efficient space-filling form for an adsorbed hydrogen gas vehicle storage tank. To optimize hydrogen storage capacity, we studied three fabrication process parameters: carbon-to-binder ratio, compaction temperature, and pyrolysis atmosphere. We found that carbon-to-binder ratio and pyrolysis atmosphere have influences on gravimetric excess adsorption. Compaction temperature has large influences on gravimetric and volumetric storage capacity. We have been able to optimize these parameters for high hydrogen storage. All monolith uptakes (up to 260 bar) were measured by a custom-built, volumetric, reservoir-type instrument.

  8. Evidence for ambient-temperature reversible catalytic hydrogenation in Pt-doped carbons.

    PubMed

    Liu, Xiao Ming; Tang, Youjian; Xu, En Shi; Fitzgibbons, Thomas C; Larsen, Gregory S; Gutierrez, Humberto R; Tseng, Huan-Hsiung; Yu, Ming-Sheng; Tsao, Cheng-Si; Badding, John V; Crespi, Vincent H; Lueking, Angela D

    2013-01-01

    In situ high-pressure Raman spectroscopy, with corroborating density functional calculations, is used to probe C-H chemical bonds formed when dissociated hydrogen diffuses from a platinum nanocatalyst to three distinct graphenic surfaces. At ambient temperature, hydrogenation and dehydrogenation are reversible in the combined presence of an active catalyst and oxygen heteroatoms. Hydrogenation apparently occurs through surface diffusion in a chemisorbed state, while dehydrogenation requires diffusion of the chemisorbed species back to an active catalyst. PMID:23194179

  9. Elasticity of Hydrogen at High Pressures

    NASA Astrophysics Data System (ADS)

    Goncharov, A. F.; Decremps, F.; Gauthier, M.; Ayrinhac, S.; Antonangeli, D.; Freiman, Y. A.; Grechnev, A.; Tretyak, S. M.

    2015-12-01

    High-pressure elastic properties of hydrogen give insight into anisotropy, equation of state, thermodynamic properties, and intermolecular potentials of this material providing an important link to ultrahigh pressure behavior approaching transformation to metallic monatomic or molecular state. Here we present picosecond acoustics measurements of compressional sound velocities [1] combined with optical interferometry and Raman spectroscopy of H2 and D2 at 295 K up to 55 GPa. Using the equation of state determined previously [2], we deduced the transverse sound velocities and the Poisson's ratio up to 55 GPa. The latter shows a broad minimum near 45 GPa (c.f. Ref. [3]) providing a new experimentally proven insight into lattice dynamics of hydrogen at high pressure that can be compared to theoretical calculations of various levels [4]. [1] F. Decremps, M. Gauthier, S. Ayrinhac, L. Bove, L. Belliard, B. Perrin, M. Morand, G. Le Marchand, F. Bergame, J. Philippe, Ultrasonics, 56 (2015) 129-140. [2] P. Loubeyre, R. LeToullec, D. Hausermann, M. Hanfland, R.J. Hemley, H.K. Mao, L.W. Finger, Nature, 383 (1996) 702-704. [3] C.-s. Zha, T.S. Duffy, H.-k. Mao, R.J. Hemley, Phys. Rev. B, 48 (1993) 9246-9255. [4] Y.A. Freiman, A. Grechnev, S.M. Tretyak, A.F. Goncharov, E. Gregoryanz, Fizika Nizkikh Temperatur, 41 (2015) 571.

  10. Hydrogen trapping in high-strength steels

    SciTech Connect

    Pound, B.G.

    1998-10-09

    Hydrogen trapping in three high-strength steels -- AerMet 100 and AISI 4340 and H11 -- was studied using a potentiostatic pulse technique. Irreversible trapping constants (k) and hydrogen entry fluxes were determined for these alloys in 1 mol/1 acetic acid/1 mol/1 sodium acetate. The order of the k values for the three steels and two 18Ni maraging steels previously studies inversely parallels their threshold stress intensities for stress corrosion cracking (K{sub 1SCC}). Irreversible trapping in AerMet 100 varies with aging temperature and appears to depend on the type of carbide (Fe{sub 3}C or M{sub 2}C) present. For 4340 steel, k can be correlated with K{sub 1SCC} over a range of yield strengths. The change in k is consistent with a change in the principal type of irreversible trap from matrix boundaries to incoherent Fe{sub 3}C. The principal irreversible traps in H11 at high yield strengths are thought to be similar to those in 4340 steel.

  11. Measuring Rocket Engine Temperatures with Hydrogen Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Wehrmeyer, Joseph A.; Osborne, Robin J.; Trinh, Huu P.; Turner, James (Technical Monitor)

    2001-01-01

    Optically accessible, high pressure, hot fire test articles are available at NASA Marshall for use in development of advanced rocket engine propellant injectors. Single laser-pulse ultraviolet (UV) Raman spectroscopy has been used in the past in these devices for analysis of high pressure H2- and CH4-fueled combustion, but relies on an independent pressure measurement in order to provide temperature information. A variation of UV Raman (High Resolution Hydrogen Raman Spectroscopy) is under development and will allow temperature measurement without the need for an independent pressure measurement, useful for flows where local pressure may not be accurately known. The technique involves the use of a spectrometer with good spectral resolution, requiring a small entrance slit for the spectrometer. The H2 Raman spectrum, when created by a narrow linewidth laser source and obtained from a good spectral resolution spectrograph, has a spectral shape related to temperature. By best-fit matching an experimental spectrum to theoretical spectra at various temperatures, a temperature measurement is obtained. The spectral model accounts for collisional narrowing, collisional broadening, Doppler broadening, and collisional line shifting of each Raman line making up the H2 Stokes vibrational Q-branch spectrum. At pressures from atmospheric up to those associated with advanced preburner components (5500 psia), collisional broadening though present does not cause significant overlap of the Raman lines, allowing high resolution H2 Raman to be used for temperature measurements in plumes and in high pressure test articles. Experimental demonstrations of the technique are performed for rich H2-air flames at atmospheric pressure and for high pressure, 300 K H2-He mixtures. Spectrometer imaging quality is identified as being critical for successful implementation of technique.

  12. 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.

  13. Towards 9 weight percent, reversible, room temperature hydrogen adsorbents: Hydrogen saturated organometallic bucky balls

    NASA Astrophysics Data System (ADS)

    Zhao, Yufeng

    2005-03-01

    A new concept for high-capacity hydrogen absorbents is introduced by first-principles calculations. Transition metal (TM) atoms bound to fullerenes are proposed as a medium for high density, room temperature, ambient pressure storage of hydrogen. TMs bind to C60 or C48B12 by charge transfer interactions to produce stable organometallic bucky balls (OBBs) and bind to multiple dihydrogen molecules through the so-called Kubas interaction [1]. A particular scandium OBB can bind as many as eleven hydrogen atoms per TM, ten of which are bound in the form of dihydrogen molecular ligands that can be adsorbed and desorbed reversibly. In this case, the calculated binding energy is around 0.3 eV/H2, which is ideal for use on-board vehicles. The theoretical maximum retrievable H2 storage density is about 9 weight percent. This work was supported by the U.S. DOE EERE, BES/MS, and BES/CS under contract No. DEAC36-99GO10337. [1] G.J. Kubas, J. Organometallic Chem. 635, 37 (2001).

  14. Gaseous hydrogen embrittlement of high strength steels

    NASA Technical Reports Server (NTRS)

    Gangloff, R. P.; Wei, R. P.

    1977-01-01

    The effects of temperature, hydrogen pressure, stress intensity, and yield strength on the kinetics of gaseous hydrogen assisted crack propagation in 18Ni maraging steels were investigated experimentally. It was found that crack growth rate as a function of stress intensity was characterized by an apparent threshold for crack growth, a stage where the growth rate increased sharply, and a stage where the growth rate was unchanged over a significant range of stress intensity. Cracking proceeded on load application with little or no detectable incubation period. Gaseous hydrogen embrittlement susceptibility increased with increasing yield strength.

  15. Light-induced long-range hydrogen motion in a-Si:H at room temperature

    NASA Astrophysics Data System (ADS)

    Cheong, Hyeonsik M.; Lee, S.-H.; Nelson, B. P.; Mascarenhas, A.; Deb, S. K.

    2001-03-01

    We demonstrate that one can detect minuscule amounts of hydrogen diffusion out of a-Si:H under illumination at room temperature, by monitoring the changes in the Raman spectrum of a-WO3 as a function of illumination. The Staebler-Wronski effect, the light-induce creation of metastable defects in hydrogenated amorphous silicon (a-Si:H), has been one of the major problems that has limited the performance of solar cells based on this material. The recently suggested ¡®hydrogen collision model¡¯ can explain many aspects of the Staebler-Wronski effect, but assumes that the photogenerated mobile hydrogen atoms can move a long distance at room temperature. However, light-induced hydrogen motion in a-Si:H has not been experimentally observed at room temperature. We utilized the high sensitivity of the Raman spectrum of electrochromic a-WO3 to hydrogen insertion to probe the long-range motion of hydrogen at room temperature. We deposited a thin (200 nm) layer of a-WO3 on top of a-Si:H, and under illumination, a change in the Raman spectrum was detected. By comparing the Raman signal changes with those for control experiments where hydrogen is electrochemically inserted into a-WO_3, we can estimate semiquantitatively the amount of hydrogen that diffuses out of the a-Si:H layer.

  16. TENSILE TESTING OF CARBON STEEL IN HIGH PRESSURE HYDROGEN

    SciTech Connect

    Duncan, A; Thad Adams, T; Ps Lam, P

    2007-05-02

    An infrastructure of new and existing pipelines and systems will be required to carry and to deliver hydrogen as an alternative energy source under the hydrogen economy. Carbon and low alloy steels of moderate strength are currently used in hydrogen delivery systems as well as in the existing natural gas systems. It is critical to understand the material response of these standard pipeline materials when they are subjected to pressurized hydrogen environments. The methods and results from a testing program to quantify hydrogen effects on mechanical properties of carbon steel pipeline and pipeline weld materials are provided. Tensile properties of one type of steel (A106 Grade B) in base metal, welded and heat affected zone conditions were tested at room temperature in air and high pressure (10.34 MPa or 1500 psig) hydrogen. A general reduction in the materials ability to plastically deform was noted in this material when specimens were tested in hydrogen. Furthermore, the primary mode of fracture was changed from ductile rupture in air to cleavage with secondary tearing in hydrogen. The mechanical test results will be applied in future analyses to evaluate service life of the pipelines. The results are also envisioned to be part of the bases for construction codes and structural integrity demonstrations for hydrogen service pipeline and vessels.

  17. A new high strength alloy for hydrogen fueled propulsion systems

    NASA Technical Reports Server (NTRS)

    Mcpherson, W. B.

    1986-01-01

    This paper describes the development of a high-strength alloy (1241 MPa ultimate and 1103 MPa yield, with little or no degradation in hydrogen) for application in advanced hydrogen-fueled rocket engines. Various compositions of the Fe-Ni-Co-Cr system with elemental additions of Cb, Ti and Al are discussed. After processing, notched tensile specimens were tested in 34.5-MPa hydrogen at room temperature, as the main screening test. The H2/air notch tensile ratio was used as the selection/rejection criterion. The most promising alloys are discussed.

  18. HIGH TEMPERATURE THERMOCOUPLE

    DOEpatents

    Eshayu, A.M.

    1963-02-12

    This invention contemplates a high temperature thermocouple for use in an inert or a reducing atmosphere. The thermocouple limbs are made of rhenium and graphite and these limbs are connected at their hot ends in compressed removable contact. The rhenium and graphite are of high purity and are substantially stable and free from diffusion into each other even without shielding. Also, the graphite may be thick enough to support the thermocouple in a gas stream. (AEC)

  19. [The Clinical Application Status and Development Trends of Hydrogen Peroxide Low Temperature Plasma Sterilizers].

    PubMed

    Zhuang, Min; Zheng, Yunxin; Chen, Ying; Hou, Bin; Xu, Zitian

    2016-01-01

    The hydrogen peroxide low temperature plasma sterilization technology solved the problems of thermo-sensitive materials' disinfection and sterilization based on its development and unique characteristics. This paper introduced the researches of clinical application quality control, and showed the hydrogen peroxide low temperature plasma sterilizers were being widely used in hospitals and highly recognized. According to the clinical data and the literatures of the domestic equipment in preliminary application, it could be concluded that the technology maturity of domestic hydrogen peroxide low temperature plasma sterilizers was in a high level. The advantages of using domestic hydrogen peroxide low temperature plasma sterilizers to do disinfection and sterilization included lower cost, safer, faster and non-toxic, etc. Also the management system should be improved and the clinical staff should master the technical essentials, obey the procedures strictly, verify periodically and offer full monitoring to upgrade the quality of sterilization. PMID:27197500

  20. High temperature thermometric phosphors

    DOEpatents

    Allison, Stephen W.; Cates, Michael R.; Boatner, Lynn A.; Gillies, George T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO.sub.4 :Dy.sub.(x),Eu.sub.y) wherein: 0.1 wt %.ltoreq.x.ltoreq.20 wt % and 0.1 wt %.ltoreq.y.ltoreq.20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.

  1. High temperature thermometric phosphors

    DOEpatents

    Allison, S.W.; Cates, M.R.; Boatner, L.A.; Gillies, G.T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO{sub 4}:Dy{sub x},Eu{sub y} wherein: 0.1 wt % {<=} x {<=} 20 wt % and 0.1 wt % {<=} y {<=} 20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopant. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions. 2 figs.

  2. Beam transport of low temperature atomic hydrogen

    NASA Astrophysics Data System (ADS)

    Kaufman, W. A.

    1993-12-01

    Analytic calculations and particle tracking simulations are presented for a polarized atomic hydrogen beam produced by extraction from an ultra-cold (T=300 mK) helium film coated cell in a large solenoidal magnetic field (12 T). Initial focusing of states 1 and 2 by the solenoidal field and subsequent focusing by a sextupole are examined within the constraints imposed by the requirements of the polarized jet for the experiments NEPTUN and NEPTUN-A at UNK.

  3. High-temperature electronics

    NASA Astrophysics Data System (ADS)

    Seng, Gary T.

    1987-11-01

    In recent years, there was a growing need for electronics capable of sustained high-temperature operation for aerospace propulsion system instrumentation, control and condition monitoring, and integrated sensors. The desired operating temperature in some applications exceeds 600 C, which is well beyond the capability of currently available semiconductor devices. Silicon carbide displays a number of properties which make it very attractive as a semiconductor material, one of which is the ability to retain its electronic integrity at temperatures well above 600 C. An IR-100 award was presented to NASA Lewis in 1983 for developing a chemical vapor deposition process to grow single crystals of this material on standard silicon wafers. Silicon carbide devices were demonstrated above 400 C, but much work remains in the areas of crystal growth, characterization, and device fabrication before the full potential of silicon carbide can be realized. The presentation will conclude with current and future high-temperature electronics program plans. Although the development of silicon carbide falls into the category of high-risk research, the future looks promising, and the potential payoffs are tremendous.

  4. Plasma electron temperature and the entropy effect on hydrogen production

    NASA Astrophysics Data System (ADS)

    Chakartnarodom, Parinya

    The thesis is that the interaction between the microwave induced electric field and a conductive material will produce plasma with high effective temperature such that it is thermodynamically and kinetically possible to produce small molecules from large molecules. The high effective temperature increases the potency of the entropy term such that small molecules are produced from large molecules even though the enthalpy for the process is positive. This hypothesis will be tested in several reactions for which the entropy change is positive. The plasma enhanced chemical reactions examined here may also be important in the practical application of alternative fuel production. The specific reactions of interest to this thesis are: (1) H 2O→H2 + 1/2 O2; DeltaGo ( kJ) = 247.5--0.056T, (2) 1/2 N2 + H2O→ H2 + NO; DeltaGo (kJ) = 338.45--0.069T, (3) C + H2O →Fe H2 + CO; Delta Go(kJ) = 135.8--0.143 T, (4) C6H 10O5 → 5H2 + C + 5CO; DeltaGo( kJ) = 711.3--2.48T. Experiments are carried out to examine the chemical species present within the plasma by the optical emission spectrometer (OES) and in the resultant gas outflow by the flue gas analyzer as a function of incoming gas composition and composition of the solid materials at the point of plasma initiation. The chemical and plasma reactions observed experimentally will be compared to thermodynamic calculations as a method to test the hypothesis. In addition, hydrogen production from water and from water and nitrogen at elevated effective temperature produces products, which recombine with negative free energy change at lower temperatures. Based on our initial results, it is also necessary to hypothesize that spatiotemporal plasma discharges can produce molecular hydrogen and an associated oxidant at an elevated effective temperature such that the mixture is 'quenched' to a lower temperature where said mixture is kinetically stabilized against spontaneous recombination. In all experiments, the results from OES show

  5. High temperature adsorption measurements

    SciTech Connect

    Bertani, R.; Parisi, L.; Perini, R.; Tarquini, B.

    1996-01-24

    Adsorption phenomena are a rich and rather new field of study in geothermal research, in particular at very high temperature. ENEL is interested in the exploitation of geothermal regions with superheated steam, and it is important to understand the behavior of water-rock interaction. We have analyzed in the 170-200 °C temperature range four samples of Monteverdi cuttings; the next experimental effort will be at 220 °C and over in 1996. The first results of the 1995 runs are collected in this paper. We can highlight four main items: 1. At relative pressures over 0.6 the capillarity forces are very important. 2. There is no significant temperature effect. 3. Adsorbed water can be present, and it is able to multiply by a factor of 15 the estimated reserve of super-heated steam only. 4. Pores smaller than 15 Å do not contribute to the adsorbed mass.

  6. High temperature adsorption measurements

    SciTech Connect

    Bertani, R.; Parisi, L.; Perini, R.; Tarquini, B.

    1996-12-31

    Adsorption phenomena are a rich and rather new field of study in geothermal research, in particular at very high temperature. ENEL is interested in the exploitation of geothermal regions with super-heated steam, and it is important to understand the behavior of water-rock interaction. We have analyzed in the 170-200{degrees}C temperature range four samples of Monteverdi cuttings; the next experimental effort will be at 220{degrees}C and over in 1996. The first results of the 1995 runs are collected in this paper. We can highlight four main items: (1) At relative pressures over 0.6 the capillarity forces are very important. (2) There is no significant temperature effect. (3) Adsorbed water can be present, and it is able to multiply by a factor of 15 the estimated reserve of super-heated steam only. (4) Pores smaller than 15 {Angstrom} do not contribute to the adsorbed mass.

  7. Hydrogen solubility in cristobalite at high pressure.

    PubMed

    Efimchenko, Vadim S; Fedotov, Vladimir K; Kuzovnikov, Mikhail A; Meletov, Konstantin P; Bulychev, Boris M

    2014-11-01

    Powder samples of cristobalite-I are loaded with hydrogen at pressures up to 90 kbar and T = 250 °C and quenched under pressure to the liquid N2 temperature. The quenched samples are examined at ambient pressure by X-ray diffraction, Raman spectroscopy, and thermal desorption analysis. The hydrogen content of the samples is found to increase with pressure and reach a molecular ratio of H2/SiO2 ∼ 0.10 at P = 90 kbar. At ambient pressure, the samples consist of a mixture of approximately 80% cristobalite-I phase and 20% cristobalite-II-like phase, the crystal lattices of both phases being slightly expanded due to the hydrogen uptake. According to Raman spectroscopy, the hydrogen is dissolved in these phases in the form of H2 molecules. PMID:25322160

  8. Thermal Desorption Analysis of Hydrogen in High Strength Martensitic Steels

    NASA Astrophysics Data System (ADS)

    Enomoto, M.; Hirakami, D.; Tarui, T.

    2012-02-01

    Thermal desorption analyses (TDA) were conducted in high strength martensitic steels containing carbon from 0.33 to 1.0 mass pct, which were charged with hydrogen at 1223 K (950 °C) under hydrogen of one atmospheric pressure and quenched to room temperature. In 0.33C steel, which had the highest M s temperature, only one desorption peak was observed around 373 K (100 °C), whereas two peaks, one at a similar temperature and the other around and above 573 K (300 °C), were observed in the other steels, the height of the second peak increasing with carbon content. In 0.82C steel, both peaks disappeared during exposure at room temperature in 1 week, whereas the peak heights decreased gradually over 2 weeks in specimens electrolytically charged with hydrogen and aged for varying times at room temperature. From computer simulation, by means of the McNabb-Foster theory coupled with theories of carbon segregation, these peaks are likely to be due to trapping of hydrogen in the strain fields and cores of dislocations, and presumably to a lesser extent in prior austenite grain boundaries. The results also indicate that carbon atoms prevent and even expel hydrogen from trapping sites during quenching and aging in these steels.

  9. High Temperature Metallic Seal Development

    NASA Astrophysics Data System (ADS)

    Datta, Amit; More, D. Greg

    2002-10-01

    A high temperature static seal capable of long term operation at temperature ranging from 1400 F to 1800 F is presented. The contents include: 1) Development approach; 2) Stress relaxation curves; 3) High temperature seal test rig; 4) High temperature seal design; and 5) High temperature seal testing. This paper is in viewgraph form.

  10. High Temperature Thermosets

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M.

    1999-01-01

    A thermoset or network polymer is an organic material where the molecules are tied together through chemical bonds (crosslinks) and therefore they cannot move past one another. As a result, these materials exhibit a certain degree of dimensional stability. The chemical composition and the degree of crosslink density of the thermoset have a pronounced effect upon the properties. High temperature thermosets offer a favorable combination of properties that makes them attractive for many applications. Their most important features are the excellent processability particularly of the low molecular weight precusor forms, the chemical and solvent resistance and the dimensional stability. The market for high temperature thermosets will increase as new uses for them are uncovered and new thermosets with better combinations of properties are developed.

  11. High temperature future

    SciTech Connect

    Sheinkopf, K.

    1994-09-01

    During the past few years, there have been dramatic accomplishments and success of high temperature solar thermal systems and significant development of these systems. High temperature technologies, about 500 F and higher, such as dish engines, troughs, central receiver power towers and solar process heat systems, have been tested, demonstrated and used in an array of applications, including many cost-effective utility bulk power production and demand side supply projects in the United States. Large systems provide power and hot water to prisons, schools, nursing homes and other institutions. Joint ventures with industry, utility projects, laboratory design assistance and other activities are building a solid industry of US solar thermal systems ready for use today.

  12. Evidence of Superstoichiometric H/d Lenr Active Sites and High-Temperature Superconductivity in a Hydrogen-Cycled Pd/PdO

    NASA Astrophysics Data System (ADS)

    Lipson, A. G.; Castano, C. H.; Miley, G. H.; Lyakhov, B. F.; Tsivadze, A. Yu.; Mitin, A. V.

    Electron transport and magnetic properties have been studied in a 12.5 μm thick Pd foil with a thermally grown oxide and a low-residual concentration of hydrogen. This foil was deformed by cycling across the Pd hydride miscibility gap and the residual hydrogen was trapped at dislocation cores. Anomalies of both resistance and magnetic susceptibility have been observed below 70 K, indicating the appearance of excess conductivity and a diamagnetic response that we interpret in terms of filamentary superconductivity. These anomalies are attributed to a condensed hydrogen-rich phase at dislocation cores. The role of deuterium rich dislocation cores as LENR active sites is discussed.

  13. High-temperature superconductivity

    NASA Astrophysics Data System (ADS)

    Chin, Ken C.

    1990-01-01

    The current status of high-temperature superconductivity (HTSC) and near-term prospects are briefly reviewed with particular reference to Lockheed's experience. Emphasis is placed on an integrated approach to systems applications of HTSC thin films, which hold the greatest near-term promise. These new materials are applied in the production of smaller, more sensitive, and more efficient electronic components to meet the ever-increasing demands for higher-performance signal acquisition and processing systems, communications systems, and computers.

  14. High temperature adhesives

    NASA Technical Reports Server (NTRS)

    St.clair, Terry L.

    1991-01-01

    The aerospace and electronics industries have an ever increasing need for higher performance materials. In recent years, linear aromatic polyimides have been proven to be a superior class of materials for various applications in these industries. The use of this class of polymers as adhesives is continuing to increase. Several NASA Langley developed polyimides show considerable promise as adhesives because of their high glass transition temperatures, thermal stability, resistance to solvents/water, and their potential for cost effective manufacture.

  15. Synthesis and characterizations of palladium catalysts with high activity and stability for formic acid oxidation by hydrogen reduction in ethylene glycol at room temperature

    NASA Astrophysics Data System (ADS)

    Wu, Meixia; Li, Muwu; Wu, Xin; Li, Yuexia; Zeng, Jianhuang; Liao, Shijun

    2015-10-01

    In this work, a Pd/C catalyst with high activity as well as excellent stability has been prepared by hydrogen gas reduction of Pd(II) precursor in ethylene glycol solution with the assistance of appropriate amount of sodium citrate. Pd nanoparticles with an average particle size of 3.8 nm and excellent uniformity are obtained. The Pd/C catalyst synthesized in this work shows an electrochemical surface area of 68.6 m2 g-1 and displays activities of 819 A g-1. Strikingly, the Pd/C catalyst also exhibits excellent stability, which has been confirmed by its slow activity decay under repeated potential cycles as well as chronoamperometric test. The activity for Pd/C at the 300th and 500th cycle remains at 5.5 and 2.4 mA cm-2, respectively, which is 25% and 11% of its initial value, respectively. The oxidation currents at the Pd/C and Pd/C-Citrate (control) at 0 V decrease to 44% and 25% of their initial values. Transmission electron microscopy observations on the Pd/C catalyst after 1000 potential cycles reveal that, in addition to carbon support corrosion, Pd agglomeration together with more serious Pd dissolution occur at the same time, leading to a decrease of the electrocatalytic performance.

  16. Competitively priced hydrogen via high-efficiency nuclear electrolysis

    NASA Technical Reports Server (NTRS)

    Escher, W. J. D.; Donakowski, T. D.

    1977-01-01

    A fully dedicated nuclear-electrolytic hydrogen-production facility, based on advanced (1985) technology, has been synthesized and assessed at the conceptual level. The facility integrates an HTGR operating a binary shaftpower-extraction cycle at 980 C top temperature, direct dc electricity generation via acyclic generators, and high-current density high-pressure electrolyzers based on the solid polymer electrolyte approach. All subsystems are close-coupled and optimally interfaced. Pipeline-pressure hydrogen and coproduct oxygen are produced at 6900 kPa. On consistent costing bases, the advanced facility concept was found to provide hydrogen costs that were approximately half those associated with conventional, contemporary-technology nuclear electrolysis. The nuclear heat-to-hydrogen energy conversion efficiency for the advanced system was estimated as 43%, against 25% for the baseline present-day approach.

  17. MECHANICAL TESTING OF CARBON STEEL IN HIGH PRESSURE HYDROGEN

    SciTech Connect

    Duncan, A

    2006-05-11

    The methods and interim results from a testing program to quantify hydrogen effects on mechanical properties of carbon steel pipeline and pipeline weld materials are provided. The scope is carbon steels commonly used for natural gas pipelines in the United States that are candidates for hydrogen service in the hydrogen economy. The mechanical test results will be applied in future analyses to evaluate service life of the pipelines. The results are also envisioned to be part of the bases for construction codes and structural integrity demonstrations for hydrogen service pipeline and vessels. Tensile properties of one type of steel (A106 Grade B) in base metal, welded and heat affected zone conditions were tested at room temperature in air and high pressure (1500 psig) hydrogen. A general reduction in the materials ability to plastically deform was noted in this material when specimens were tested in 1500 psig hydrogen. Furthermore, the primary mode of fracture was changed from ductile rupture in air to cleavage with secondary tearing in hydrogen. The mechanical test program will continue with tests to quantify the fracture behavior in terms of J-R curves for these materials at air and hydrogen pressure conditions.

  18. Advances in materials for room temperature hydrogen sensors.

    PubMed

    Arya, Sunil K; Krishnan, Subramanian; Silva, Hayde; Jean, Sheila; Bhansali, Shekhar

    2012-06-21

    Hydrogen (H(2)), as a source of energy, continues to be a compelling choice in applications ranging from fuel cells and propulsion systems to feedstock for chemical, metallurgical and other industrial processes. H(2), being a clean, reliable, and affordable source, is finding ever increasing use in distributed electric power generation and H(2) fuelled cars. Although still under 0.1%, the distributed use of H(2) is the fastest growing area. In distributed H(2) storage, distribution, and consumption, safety continues to be a critical aspect. Affordable safety systems for distributed H(2) applications are critical for the H(2) economy to take hold. Advances in H(2) sensors are driven by specificity, reliability, repeatability, stability, cost, size, response time, recovery time, operating temperature, humidity range, and power consumption. Ambient temperature sensors for H(2) detection are increasingly being explored as they offer specificity, stability and robustness of high temperature sensors with lower operational costs and significantly longer operational lifetimes. This review summarizes and highlights recent developments in room temperature H(2) sensors. PMID:22582176

  19. Hydrogen Confinement in Carbon Nanopores: Extreme Densification at Ambient Temperature

    SciTech Connect

    Gallego, Nidia C; He, Lilin; Saha, Dipendu; Contescu, Cristian I; Melnichenko, Yuri B

    2011-01-01

    In-situ small angle neutron scattering (SANS) studies of hydrogen confined in small pores of polyfurfuryl alcohol-derived activated carbon (PFAC) at room-temperature provided for the first time its phase behavior in equilibrium with external H2 at pressures up to 200 bar. The data was used to evaluate the density of the adsorbed fluid, which appears to be a function of both pore size and pressure, and approaches the liquid hydrogen density in narrow nanopores at 200 bar. The surface-molecule interactions responsible for densification of hydrogen within the pores create internal pressures which exceed by a factor of up to ~ 60 the external gas pressures, confirming the benefits of adsorptive over compressive storage. These results can be utilized to guide the development of new carbon adsorbents tailored for maximum hydrogen storage capacities at near ambient temperatures.

  20. Hydrogen atom temperature measured with wavelength-modulated laser absorption spectroscopy in large scale filament arc negative hydrogen ion source

    SciTech Connect

    Nakano, H. Goto, M.; Tsumori, K.; Kisaki, M.; Ikeda, K.; Nagaoka, K.; Osakabe, M.; Takeiri, Y.; Kaneko, O.; Nishiyama, S.; Sasaki, K.

    2015-04-08

    The velocity distribution function of hydrogen atoms is one of the useful parameters to understand particle dynamics from negative hydrogen production to extraction in a negative hydrogen ion source. Hydrogen atom temperature is one of the indicators of the velocity distribution function. To find a feasibility of hydrogen atom temperature measurement in large scale filament arc negative hydrogen ion source for fusion, a model calculation of wavelength-modulated laser absorption spectroscopy of the hydrogen Balmer alpha line was performed. By utilizing a wide range tunable diode laser, we successfully obtained the hydrogen atom temperature of ∼3000 K in the vicinity of the plasma grid electrode. The hydrogen atom temperature increases as well as the arc power, and becomes constant after decreasing with the filling of hydrogen gas pressure.

  1. The temperature variation of hydrogen diffusion coefficients in metal alloys

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1990-01-01

    Hydrogen diffusion coefficients were measured as a function of temperature for a few metal alloys using an electrochemical evolution technique. Results from these measurements are compared to those obtained by the time-lag method. In all cases, diffusion coefficients obtained by the electrochemical method are larger than those by the time-lag method by an order of magnitude or more. These differences are attributed mainly to hydrogen trapping.

  2. HIGH EFFICIENCY GENERATION OF HYDROGEN FUELS USING NUCLEAR POWER

    SciTech Connect

    BROWN,LC; BESENBRUCH,GE; LENTSCH,RD; SCHULTZ,KR; FUNK,JF; PICKARD,PS; MARSHALL,AC; SHOWALTER,SK

    2003-06-01

    OAK B202 HIGH EFFICIENCY GENERATION OF HYDROGEN FUELS USING NUCLEAR POWER. Combustion of fossil fuels, used to power transportation, generate electricity, heat homes and fuel industry provides 86% of the world's energy. Drawbacks to fossil fuel utilization include limited supply, pollution, and carbon dioxide emissions. Carbon dioxide emissions, thought to be responsible for global warming, are now the subject of international treaties. Together, these drawbacks argue for the replacement of fossil fuels with a less-polluting potentially renewable primary energy such as nuclear energy. Conventional nuclear plants readily generate electric power but fossil fuels are firmly entrenched in the transportation sector. Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. Hydrogen will be particularly advantageous when coupled with fuel cells. Fuel cells have higher efficiency than conventional battery/internal combustion engine combinations and do not produce nitrogen oxides during low-temperature operation. Contemporary hydrogen production is primarily based on fossil fuels and most specifically on natural gas. When hydrogen is produced using energy derived from fossil fuels, there is little or no environmental advantage. There is currently no large scale, cost-effective, environmentally attractive hydrogen production process available for commercialization, nor has such a process been identified. The objective of this work is to find an economically feasible process for the production of hydrogen, by nuclear means, using an advanced high-temperature nuclear reactor as the primary energy source. Hydrogen production by thermochemical water-splitting (Appendix A), a chemical process that accomplishes the decomposition of water into hydrogen and oxygen using only heat or, in the case of a hybrid thermochemical process, by a combination of heat and electrolysis, could meet these goals. Hydrogen produced from fossil

  3. High temperature strain gages

    NASA Technical Reports Server (NTRS)

    Gregory, Otto J. (Inventor); You, Tao (Inventor)

    2011-01-01

    A ceramic strain gage based on reactively sputtered indium-tin-oxide (ITO) thin films is used to monitor the structural integrity of components employed in aerospace propulsion systems operating at temperatures in excess of 1500.degree. C. A scanning electron microscopy (SEM) of the thick ITO sensors reveals a partially sintered microstructure comprising a contiguous network of submicron ITO particles with well defined necks and isolated nanoporosity. Densification of the ITO particles was retarded during high temperature exposure with nitrogen thus stabilizing the nanoporosity. ITO strain sensors were prepared by reactive sputtering in various nitrogen/oxygen/argon partial pressures to incorporate more nitrogen into the films. Under these conditions, sintering and densification of the ITO particles containing these nitrogen rich grain boundaries was retarded and a contiguous network of nano-sized ITO particles was established.

  4. High Temperature Piezoelectric Drill

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom

    2012-01-01

    Venus is one of the planets in the solar systems that are considered for potential future exploration missions. It has extreme environment where the average temperature is 460 deg C and its ambient pressure is about 90 atm. Since the existing actuation technology cannot maintain functionality under the harsh conditions of Venus, it is a challenge to perform sampling and other tasks that require the use of moving parts. Specifically, the currently available electromagnetic actuators are limited in their ability to produce sufficiently high stroke, torque, or force. In contrast, advances in developing electro-mechanical materials (such as piezoelectric and electrostrictive) have enabled potential actuation capabilities that can be used to support such missions. Taking advantage of these materials, we developed a piezoelectric actuated drill that operates at the temperature range up to 500 deg C and the mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) configuration. The detailed results of our study are presented in this paper

  5. Spectroscopic study of low-temperature hydrogen absorption in palladium

    SciTech Connect

    Ienaga, K. Takata, H.; Onishi, Y.; Inagaki, Y.; Kawae, T.; Tsujii, H.; Kimura, T.

    2015-01-12

    We report real-time detection of hydrogen (H) absorption in metallic palladium (Pd) nano-contacts immersed in liquid H{sub 2} using inelastic electron spectroscopy (IES). After introduction of liquid H{sub 2}, the spectra exhibit the time evolution from the pure Pd to the Pd hydride, indicating that H atoms are absorbed in Pd nano-contacts even at the temperature where the thermal process is not expected. The IES time and bias voltage dependences show that H absorption develops by applying bias voltage 30 ∼ 50 mV, which can be explained by quantum tunneling. The results represent that IES is a powerful method to study the kinetics of high density H on solid surface.

  6. Application of hydrogenation to low-temperature cleaning of the Si(001) surface in the processes of molecular-beam epitaxy: Investigation by scanning tunneling microscopy, reflected high-energy electron diffraction, and high resolution transmission electron microscopy

    SciTech Connect

    Arapkina, L. V.; Krylova, L. A.; Chizh, K. V.; Chapnin, V. A.; Uvarov, O. V.; Yuryev, V. A.

    2012-07-01

    Structural properties of the clean Si(001) surface obtained as a result of low-temperature (470-650 Degree-Sign C) pre-growth annealings of silicon wafers in a molecular-beam epitaxy chamber have been investigated. To decrease the cleaning temperature, a silicon surface was hydrogenated in the process of a preliminary chemical treatment in HF and NH{sub 4}F aqueous solutions. It has been shown that smooth surfaces composed of wide terraces separated by monoatomic steps can be obtained by dehydrogenation at the temperatures Greater-Than-Or-Equivalent-To 600 Degree-Sign C, whereas clean surfaces obtained at the temperatures <600 Degree-Sign C are rough. It has been found that there exists a dependence of structural properties of clean surfaces on the temperature of hydrogen thermal desorption and the process of the preliminary chemical treatment. The frequency of detachment/attachment of Si dimers from/to the steps and effect of the Ehrlich-Schwoebel barrier on ad-dimer migration across steps have been found to be the most probable factors determining a degree of the resultant surface roughness.

  7. Thermodynamics and Transport Phenomena in High Temperature Steam Electrolysis Cells

    SciTech Connect

    James E. O'Brien

    2012-03-01

    Hydrogen can be produced from water splitting with relatively high efficiency using high temperature electrolysis. This technology makes use of solid-oxide cells, running in the electrolysis mode to produce hydrogen from steam, while consuming electricity and high temperature process heat. The overall thermal-to-hydrogen efficiency for high temperature electrolysis can be as high as 50%, which is about double the overall efficiency of conventional low-temperature electrolysis. Current large-scale hydrogen production is based almost exclusively on steam reforming of methane, a method that consumes a precious fossil fuel while emitting carbon dioxide to the atmosphere. An overview of high temperature electrolysis technology will be presented, including basic thermodynamics, experimental methods, heat and mass transfer phenomena, and computational fluid dynamics modeling.

  8. Stabilization of the Low-Spin State in a Mononuclear Iron(II) Complex and High-Temperature Cooperative Spin Crossover Mediated by Hydrogen Bonding.

    PubMed

    Zheng, Sipeng; Reintjens, Niels R M; Siegler, Maxime A; Roubeau, Olivier; Bouwman, Elisabeth; Rudavskyi, Andrii; Havenith, Remco W A; Bonnet, Sylvestre

    2016-01-01

    The tetrapyridyl ligand bbpya (bbpya=N,N-bis(2,2'-bipyrid-6-yl)amine) and its mononuclear coordination compound [Fe(bbpya)(NCS)2 ] (1) were prepared. According to magnetic susceptibility, differential scanning calorimetry fitted to Sorai's domain model, and powder X-ray diffraction measurements, 1 is low-spin at room temperature, and it exhibits spin crossover (SCO) at an exceptionally high transition temperature of T1/2 =418 K. Although the SCO of compound 1 spans a temperature range of more than 150 K, it is characterized by a wide (21 K) and dissymmetric hysteresis cycle, which suggests cooperativity. The crystal structure of the LS phase of compound 1 shows strong NH⋅⋅⋅S intermolecular H-bonding interactions that explain, at least in part, the cooperative SCO behavior observed for complex 1. DFT and CASPT2 calculations under vacuum demonstrate that the bbpya ligand generates a stronger ligand field around the iron(II) core than its analogue bapbpy (N,N'-di(pyrid-2-yl)-2,2'-bipyridine-6,6'-diamine); this stabilizes the LS state and destabilizes the HS state in 1 compared with [Fe(bapbpy)(NCS)2 ] (2). Periodic DFT calculations suggest that crystal-packing effects are significant for compound 2, in which they destabilize the HS state by about 1500 cm(-1) . The much lower transition temperature found for the SCO of 2 compared to 1 appears to be due to the combined effects of the different ligand field strengths and crystal packing. PMID:26577340

  9. Plasma heating power dissipation in low temperature hydrogen plasmas

    SciTech Connect

    Komppula, J. Tarvainen, O.

    2015-10-15

    A theoretical framework for power dissipation in low temperature plasmas in corona equilibrium is developed. The framework is based on fundamental conservation laws and reaction cross sections and is only weakly sensitive to plasma parameters, e.g., electron temperature and density. The theory is applied to low temperature atomic and molecular hydrogen laboratory plasmas for which the plasma heating power dissipation to photon emission, ionization, and chemical potential is calculated. The calculated photon emission is compared to recent experimental results.

  10. Effect of ferric oxide on the high-temperature removal of hydrogen sulfide over ZnO-Fe{sub 2}O{sub 3} mixed metal oxide sorbent

    SciTech Connect

    Lee, Y.S.; Kim, H.T.; Yoo, K.O.

    1995-04-01

    The effect of ferric oxide on the removal of hydrogen sulfide over ZnO-Fe{sub 2}O{sub 3} mixed metal oxide sorbents and on the oxidative regeneration of sulfided sorbents was investigated. When ferric oxide was added to the zinc oxide, the reduction of ZnO was retarded by interaction of ZnO with ZnFe{sub 2}O{sub 4}. This interaction was confirmed by larger binding energies of Zn 2P{sub 3/2} and Zn 2P{sub 1/2}, identified by ESCA, of the ZnO-ZnFe{sub 2}O{sub 4} sorbent than those of ZnO. Zinc ferrite with a spinel structure yielded not only high H{sub 2}S removal capacity but also much SO{sub 2} generation. A linear increase of SO{sub 2} generation was confirmed up to 50 wt % Fe{sub 2}O{sub 3}. Resulting from the thermal decomposition of H{sub 2}S over metal sulfides, H{sub 2} generation increased with respect to Fe{sub 2}O{sub 3} according to a quadratic equation. Channeling, caused by sintering during sulfidation, made the flow path of the reactant change and thus pure ZnO sorbent and the sorbent containing 3 wt % Fe{sub 2}O did not sulfurate completely. Addition of Fe{sub 2}O{sub 3} prevented surface structural change like sintering of ZnO during sulfidation.

  11. High temperature detonator

    DOEpatents

    Johnson, James O.; Dinegar, Robert H.

    1988-01-01

    A detonator assembly is provided which is usable at high temperatures about 300.degree. C. A detonator body is provided with an internal volume defining an anvil surface. A first acceptor explosive is disposed on the anvil surface. A donor assembly having an ignition element, an explosive material, and a flying plate, are placed in the body effective to accelerate the flying plate to impact the first acceptor explosive on the anvil for detonating the first acceptor explosive. A second acceptor explosive is eccentrically located in detonation relationship with the first acceptor explosive to thereafter effect detonation of a main charge.

  12. High temperature drilling fluids

    SciTech Connect

    Stong, R.E.; Walinsky, S.W.

    1986-01-28

    This patent describes an aqueous drilling fluid suitable for high-temperature use. This fluid is composed of a water base. Clay is suspended in the base and from about 0.01-25 pounds per barrel total composition of a hydrolyzed terpolymer of maleic anhydride, styrene and a third monomer selected from acrylamide, methacrylamide, acrylic acid and metacrylic acid. The molar ratio of maleic anhydride to styrene to the third monomer is from about 30:10:60 to 50:40:10, and the alkali metal, ammonium and lower aliphatic amine salts thereof, the weight-average molecular weight of the hydrolyzed terpolymer is from about 500-10,000.

  13. Thin-film fiber optic hydrogen and temperature sensor system

    DOEpatents

    Nave, Stanley E.

    1998-01-01

    The invention discloses a sensor probe device for monitoring of hydrogen gas concentrations and temperatures by the same sensor probe. The sensor probe is constructed using thin-film deposition methods for the placement of a multitude of layers of materials sensitive to hydrogen concentrations and temperature on the end of a light transparent lens located within the sensor probe. The end of the lens within the sensor probe contains a lens containing a layer of hydrogen permeable material which excludes other reactive gases, a layer of reflective metal material that forms a metal hydride upon absorbing hydrogen, and a layer of semi-conducting solid that is transparent above a temperature dependent minimum wavelength for temperature detection. The three layers of materials are located at the distal end of the lens located within the sensor probe. The lens focuses light generated by broad-band light generator and connected by fiber-optics to the sensor probe, onto a reflective metal material layer, which passes through the semi-conducting solid layer, onto two optical fibers located at the base of the sensor probe. The reflected light is transmitted over fiberoptic cables to a spectrometer and system controller. The absence of electrical signals and electrical wires in the sensor probe provides for an elimination of the potential for spark sources when monitoring in hydrogen rich environments, and provides a sensor free from electrical interferences.

  14. Thin-film fiber optic hydrogen and temperature sensor system

    DOEpatents

    Nave, S.E.

    1998-07-21

    The invention discloses a sensor probe device for monitoring of hydrogen gas concentrations and temperatures by the same sensor probe. The sensor probe is constructed using thin-film deposition methods for the placement of a multitude of layers of materials sensitive to hydrogen concentrations and temperature on the end of a light transparent lens located within the sensor probe. The end of the lens within the sensor probe contains a lens containing a layer of hydrogen permeable material which excludes other reactive gases, a layer of reflective metal material that forms a metal hydride upon absorbing hydrogen, and a layer of semi-conducting solid that is transparent above a temperature dependent minimum wavelength for temperature detection. The three layers of materials are located at the distal end of the lens located within the sensor probe. The lens focuses light generated by broad-band light generator and connected by fiber-optics to the sensor probe, onto a reflective metal material layer, which passes through the semi-conducting solid layer, onto two optical fibers located at the base of the sensor probe. The reflected light is transmitted over fiber optic cables to a spectrometer and system controller. The absence of electrical signals and electrical wires in the sensor probe provides for an elimination of the potential for spark sources when monitoring in hydrogen rich environments, and provides a sensor free from electrical interferences. 3 figs.

  15. High temperature filter materials

    SciTech Connect

    Alvin, M.A.; Lippert, T.E.; Bachovchin, D.M.; Tressler, R.E.

    1992-12-01

    Objectives of this program are to identify the potential long-term thermal/chemical effects that advanced coal-based power generating system environments have on the stability of porous ceramic filter materials, as well as to assess the influence of these effects on filter operating performance and life. We have principally focused our efforts on developing an understanding of the stability of the alumina/mullite filter material at high temperature (i.e., 870, 980, and 1100{degrees}C) under oxidizing conditions which contain gas phase alkali species. Testing has typically been performed in two continuous flow-through, high temperature test facilities at the Westinghouse Science and Technology Center, using 7 cm diameter {times} 6.4 mm thick discs. (Alvin, 1992) Each disc of ceramic filter material is exposed for periods of 100 to 3,000 hours in duration. Additional efforts have been performed at Westinghouse to broaden our understanding of the stability of cordierite, cordierite-silicon nitride, reaction and sintered silicon nitride, and clay bonded silicon carbide under similar simulated advanced coal fired process conditions. The results of these efforts are presented in this paper.

  16. High temperature filter materials

    SciTech Connect

    Alvin, M.A.; Lippert, T.E.; Bachovchin, D.M. . Science and Technology Center); Tressler, R.E. )

    1992-01-01

    Objectives of this program are to identify the potential long-term thermal/chemical effects that advanced coal-based power generating system environments have on the stability of porous ceramic filter materials, as well as to assess the influence of these effects on filter operating performance and life. We have principally focused our efforts on developing an understanding of the stability of the alumina/mullite filter material at high temperature (i.e., 870, 980, and 1100[degrees]C) under oxidizing conditions which contain gas phase alkali species. Testing has typically been performed in two continuous flow-through, high temperature test facilities at the Westinghouse Science and Technology Center, using 7 cm diameter [times] 6.4 mm thick discs. (Alvin, 1992) Each disc of ceramic filter material is exposed for periods of 100 to 3,000 hours in duration. Additional efforts have been performed at Westinghouse to broaden our understanding of the stability of cordierite, cordierite-silicon nitride, reaction and sintered silicon nitride, and clay bonded silicon carbide under similar simulated advanced coal fired process conditions. The results of these efforts are presented in this paper.

  17. High Temperature Protonic Conductors

    NASA Technical Reports Server (NTRS)

    Dynys, Fred; Berger, Marie-Helen; Sayir, Ali

    2007-01-01

    High Temperature Protonic Conductors (HTPC) with the perovskite structure are envisioned for electrochemical membrane applications such as H2 separation, H2 sensors and fuel cells. Successive membrane commercialization is dependent upon addressing issues with H2 permeation rate and environmental stability with CO2 and H2O. HTPC membranes are conventionally fabricated by solid-state sintering. Grain boundaries and the presence of intergranular second phases reduce the proton mobility by orders of magnitude than the bulk crystalline grain. To enhanced protonic mobility, alternative processing routes were evaluated. A laser melt modulation (LMM) process was utilized to fabricate bulk samples, while pulsed laser deposition (PLD) was utilized to fabricate thin film membranes . Sr3Ca(1+x)Nb(2-x)O9 and SrCe(1-x)Y(x)O3 bulk samples were fabricated by LMM. Thin film BaCe(0.85)Y(0.15)O3 membranes were fabricated by PLD on porous substrates. Electron microscopy with chemical mapping was done to characterize the resultant microstructures. High temperature protonic conduction was measured by impedance spectroscopy in wet air or H2 environments. The results demonstrate the advantage of thin film membranes to thick membranes but also reveal the negative impact of defects or nanoscale domains on protonic conductivity.

  18. High Temperature Aquifer Storage

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2015-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Apart from the hydrogeological conditions, high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. After one year of planning, construction, and the successful drilling of a research well to 495 m b.s.l. the first large scale heat storage test in the Malm aquifer was finished just before Christmas 2014. An enormous technical challenge was the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10-50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye. Injection and production rates were 15 L/s. About 4 TJ of heat energy were necessary to achieve the desired water temperatures. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for the analysis of the concentration of the tracers and the cation concentrations at sampling intervals of down to 15 minutes. Additional water samples were taken and analyzed for major ions and trace elements in the laboratory. The disassembled heat exchanger proved that precipitation was successfully prevented by adding CO2 to the water before heating

  19. High Temperature Inspection System

    SciTech Connect

    Robinson, C.W.

    1999-01-26

    The Remote and Specialty Equipment Section (RSES) of the Savannah River Technology Center has developed a High Temperature Inspection System (HTIS) for remotely viewing the interior of the Defense Waste Processing Facility (DWPF) melter pour spout. The DWPF is a vitrification facility at the Savannah River Site where radioactive waste is processed, mixed and melted with glass frit in an electrically heated melter, and poured into canisters for long-term storage. The glass mixture is transferred from the melter to the canisters via the pour spout, a vertical interface between the melter and the canisters. During initial operation of the melter, problems were experienced with wicking of the glass stream to the sides of the pour spout resulting in pluggage of the pour spout. A removable insert was developed to eliminate the wicking problem. Routine cleaning of the pour spout and replacement of the insert requires that the pour spout interior be inspected on a regular basis. The HTIS was developed to perform the inspection. The HTIS provides two video images: one view for aligning the HTIS with the pour spout and the other for inspecting the pour spout wall condition and other surfaces. The HTIS is carried into the melter cell using an overhead crane and is remotely connected to the cell's telerobotic manipulator (TRM). An operator uses the TRM to insert the HTIS into the 2-inch (5.08 cm) diameter pour spout, rotate it 360 degrees, and then remove it. This application created many challenges for the inspection device, especially regarding size and temperature. The HTIS design allows the video cameras to stay below a safe operating temperature during use in the 1100 degrees C environment. Many devices are designed to penetrate a wall and extend into a heated chamber only a few inches, but the HTIS is inserted into the heated chamber 22 inches (55.88 cm). Other devices can handle the insertion length and small diameter, but they are not designed to handle the high

  20. Palladium based cermet composite for hydrogen separation at elevated temperature

    NASA Astrophysics Data System (ADS)

    Tsai, Yen-Chang; Lin, Chien-Cheng; Lin, Wei-Lin; Wang, Jeng-Han; Chen, San-Yuan; Lin, Pang; Wu, Pu-Wei

    2015-01-01

    A cermet composite consisting of palladium and BaCe0.4Zr0.4Gd0.1Dy0.1O3-x (BCZGD) is fabricated by mixing palladium and BCZGD powders in a ball mill, followed by pressing and sintering at 1450 °C for 24 h in air. The Pd-BCZGD cermet demonstrates impressive hydrogen permeation flux in a mixture of hydrogen and carbon dioxide at elevated temperature, in which the palladium plays the predominant role of facile transport in the hydrogen atoms whereas the BCZGD provides channels for proton conduction. Material characterization including scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermo-gravimetric analysis (TGA) are performed. XRD patterns indicate pure phases of fcc palladium and perovskite BCZGD. SEM images and element mapping suggest a homogeneous mixture of cermet without noticeable defect and phase segregation. TGA results confirm stability of the cermet against carbon dioxide without chemical decomposition. The hydrogen permeation flux is determined via a gas chromatography from 400 to 700 °C at various hydrogen concentration gradients. We record a hydrogen flux of 1.25 cm3 min-1 cm-2 in 50% hydrogen and 50% carbon dioxide at 700 °C, with a selectivity of H2/CO2 approaching infinity.

  1. High Temperature Aquifer Storage

    NASA Astrophysics Data System (ADS)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. Apart from high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. An enormous technical challenge is the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10 - 50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye, into a depth of about 300 m b.s.l. resp. 470 m b.s.l. Injection and production rates were 15 L/s. To achieve the desired water temperatures, about 4 TJ of heat energy were necessary. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for analysing the concentration of the dyes and the major cations at sampling intervals of down to 15 minutes. Additional water samples were taken and analysed in the laboratory. The disassembled heat exchanger prooved that precipitation was successfully prevented by adding CO2 to the water before heating. Nevertheless, hydrochemical data proved both, dissolution and precipitation processes in the aquifer. This was also suggested by the hydrochemical modelling with PhreeqC and is traced back to mixture dissolution and changing

  2. High temperature interfacial superconductivity

    SciTech Connect

    Bozovic, Ivan; Logvenov, Gennady; Gozar, Adrian Mihai

    2012-06-19

    High-temperature superconductivity confined to nanometer-scale interfaces has been a long standing goal because of potential applications in electronic devices. The spontaneous formation of a superconducting interface in bilayers consisting of an insulator (La.sub.2CuO.sub.4) and a metal (La.sub.1-xSr.sub.xCuO.sub.4), neither of which is superconducting per se, is described. Depending upon the layering sequence of the bilayers, T.sub.c may be either .about.15 K or .about.30 K. This highly robust phenomenon is confined to within 2-3 nm around the interface. After exposing the bilayer to ozone, T.sub.c exceeds 50 K and this enhanced superconductivity is also shown to originate from a 1 to 2 unit cell thick interfacial layer. The results demonstrate that engineering artificial heterostructures provides a novel, unconventional way to fabricate stable, quasi two-dimensional high T.sub.c phases and to significantly enhance superconducting properties in other superconductors. The superconducting interface may be implemented, for example, in SIS tunnel junctions or a SuFET.

  3. High-temperature resins

    NASA Technical Reports Server (NTRS)

    Serafini, T. T.

    1982-01-01

    The basic chemistry, cure processes, properties, and applications of high temperature resins known as polyimides are surveyed. Condensation aromatic polymides are prepared by reacting aromatic diamines with aromatic dianhydrides, aromatic tetracarboxylic acids, or with dialkyl esters of aromatic tetracarboxylic acids, depending on the intended end use. The first is for coatings or films while the latter two are more suitable for polyimide matrix resins. Prepreg solutions are made by dissolving reactants in an aprotic solvent, and advances in the addition of a diamine on the double bond and radical polymerization of the double bond are noted to have yielded a final cure product with void-free characteristics. Attention is given to properties of the Skybond, Pyralin, and NR-150B polyimide prepreg materials and characteristics of aging in the NP-150 polyimides. Finally, features of the NASA-developed PMR polyimides are reviewed.

  4. Low to high temperature energy conversion system

    NASA Technical Reports Server (NTRS)

    Miller, C. G. (Inventor)

    1977-01-01

    A method for converting heat energy from low temperature heat sources to higher temperature was developed. It consists of a decomposition chamber in which ammonia is decomposed into hydrogen and nitrogen by absorbing heat of decomposition from a low temperature energy source. A recombination reaction then takes place which increases the temperature of a fluid significantly. The system is of use for the efficient operation of compact or low capital investment turbine driven electrical generators, or in other applications, to enable chemical reactions that have a critical lower temperature to be used. The system also recovers heat energy from low temperature heat sources, such as solar collectors or geothermal sources, and converts it to high temperatures.

  5. Structural changes and intermolecular interactions of filled ice Ic structure for hydrogen hydrate under high pressure

    NASA Astrophysics Data System (ADS)

    Machida, S.; Hirai, H.; Kawamura, T.; Yamamoto, Y.; Yagi, T.

    2010-03-01

    High-pressure experiments of hydrogen hydrate were performed using a diamond anvil cell under conditions of 0.1-44.2 GPa and at room temperature. Also, high pressure Raman studies of solid hydrogen were performed in the pressure range of 0.1-43.7 GPa. X-ray diffractometry (XRD) for hydrogen hydrate revealed that a known high-pressure structure, filled ice Ic structure, of hydrogen hydrate transformed to a new high-pressure structure at approximately 35-40 GPa. A comparison of the Raman spectroscopy of a vibron for hydrogen molecules between hydrogen hydrate and solid hydrogen revealed that the extraction of hydrogen molecules from hydrogen hydrate occurred above 20 GPa. Also, the Raman spectra of a roton revealed that the rotation of hydrogen molecules in hydrogen hydrate was suppressed at around 20 GPa and that the rotation recovered under higher pressure. These results indicated that remarkable intermolecular interactions in hydrogen hydrate between neighboring hydrogen molecules and between guest hydrogen molecules and host water molecules might occur. These intermolecular interactions could produce the stability of hydrogen hydrate.

  6. A temperature dependent infrared absorption study of strong hydrogen bonds in bis(glycinium)oxalate

    NASA Astrophysics Data System (ADS)

    Bhatt, Himal; Deo, M. N.; Murli, C.; Vishwakarma, S. R.; Chitra, R.; Sharma, Surinder M.

    2016-05-01

    We report infrared absorption studies on Bis(glycinium)oxalate, an organic complex of the simplest amino acid Glycine, under varying temperatures in the range 77 - 350 K. The measurements have been carried out in the spectral range 400 - 4000 cm-1 and the strongest O-H---O hydrogen bond, which plays a vital role in the structural stabilization, has been studied. Subtle changes in widths of modes and temperature dependent frequency variations have been observed near 250 K. The hydrogen bonding network remains stable in the entire temperature range. This is in contrast to its reported high pressure behavior.

  7. Charged fullerenes as high-capacity hydrogen storage media.

    PubMed

    Yoon, Mina; Yang, Shenyuan; Wang, Enge; Zhang, Zhenyu

    2007-09-01

    Using first-principles calculations within density functional theory, we explore systematically the capacity of charged carbon fullerenes Cn (20 hydrogen storage media. We find that the binding strength of molecular hydrogen on either positively or negatively charged fullerenes can be dramatically enhanced to 0.18-0.32 eV, a desirable range for potential room-temperature, near ambient applications. The enhanced binding is delocalized in nature, surrounding the whole surface of a charged fullerene, and is attributed to the polarization of the hydrogen molecules by the high electric field generated near the surface of the charged fullerene. At full hydrogen coverage, these charged fullerenes can gain storage capacities of up to approximately 8.0 wt %. We also find that, contrary to intuitive expectation, fullerenes containing encapsulated metal atoms only exhibit negligible enhancement in the hydrogen binding strength, because the charge donated by the metal atoms is primarily confined inside the fullerene cages. These predictions may prove to be instrumental in searching for a new class of high-capacity hydrogen storage media. PMID:17718530

  8. Charged Fullerenes as High Capacity Hydrogen Storage Media

    SciTech Connect

    Yoon, Mina; Yang, Shenyuan; Wang, Enge; Zhang, Zhenyu

    2007-01-01

    Using first-principles calculations within density functional theory, we explore systematically the capacity of charged carbon fullerenes Cn (20≤n≤84) as hydrogen storage media. We find that the binding strength of molecular hydrogen on either positively or negatively charged fullerenes can be dramatically enhanced to 0.18-0.32 eV, a desirable range for potential room-temperature, near ambient applications. The enhanced binding is delocalized in nature, surrounding the whole surface of a charged fullerene, and is attributed to the polarization of the hydrogen molecules by the high electric field generated near the surface of the charged fullerene. At full hydrogen coverage, these charged fullerenes can gain storage capacities of up to ~8.0wt%. We also find that, contrary to intuitive expectation, fullerenes containing intercalated metal atoms only exhibit negligible enhancement in the hydrogen binding strength, because the charge donated by the metal atoms is primarily confined inside the fullerene cages. These predictions may prove to be instrumental in searching for a new class of high capacity hydrogen storage media.

  9. High Temperature Hybrid Elastomers

    NASA Astrophysics Data System (ADS)

    Drake, Kerry Anthony

    Conventional high temperature elastomers are produced by chain polymerization of olefinic or fluorinated olefinic monomers. Ultimate thermal stabilities are limited by backbone bond strengths, lower thermal stability of cross-link sites relative to backbone bonds, and depolymerization or "unzipping" at high temperatures. In order to develop elastomers with enhanced thermal stability, hybrid thermally cross-linkable polymers that consisted only of organic-inorganic and aromatic bonds were synthesized and evaluated. The addition of phenylethynyl or phenylacetylinic functional groups to these polymers resulted in conversion of the polymers into high temperature elastomers when cross-linked by thermal curing. Polyphenyoxydiphenylsilanes were synthesized via several different condensation reactions. Results of these synthetic reactions, which utilized both hydroquinone and biphenol as monomers, were systematically evaluated to determine the optimal synthetic conditions for subsequent endcapping reactions. It was determined that dichlorodiphenylsilane condensations with biphenol in toluene or THF were best suited for this work. Use of excess dichlorodiphenylsilane yielded polymers of appropriate molecular weights with terminal reactive chlorosilane groups that could be utilized for coupling with phenylethynyl reagents in a subsequent reaction. Two new synthetic routes were developed to endcap biphenoxysilanes with ethynyl containing substituents, to yield polymers with cross-linkable end groups. Endcapping by lithiumphenylacetylide and 4[(4-fluorophenylethynyl))phenol yielded two new polymers that could be thermally cross-linked on heating above 300 °C. Successful endcapping was verified chemically by 13C NMR, FTIR and Raman analysis. Exothermic peaks consistent with ethynyl curing reactions were observed in endcapped polymers by DSC. A new diacetylinic polymer was prepared through reaction of 4,4'-buta-1,3-diyne-1,4-diyldiphenol and dichlorodiphenylsilane. This

  10. Crack growth in ASME SA-105 grade 2 steel in hydrogen at ambient temperature

    NASA Technical Reports Server (NTRS)

    Walter, R. J.

    1975-01-01

    Cyclic-load crack growth measurements were performed on ASME SA-105 Grade 2 steel specimens exposed to 10,000- and 15,000-psi hydrogen and to 5000-psi helium, all at ambient temperatures. The cyclic-load crack growth rate was found to be faster in high-pressure hydrogen than in helium. Cyclic-load crack growth rates in this steel were not reduced by preloading in air to a stress intensity of 1.5 times the cyclic K sub max in hydrogen. There are indications that holding under load in hydrogen, and loading and unloading in helium retards hydrogen-accelerated cyclic-load crack growth. Cyclic frequency and R (ratio of K sub min/k sub max) were important variables determining crack growth rate. The crack growth rate increased as a logarithm of the cycle duration and decreased with increasing R.

  11. Hydrogen-induced crack nucleation in tensile testing of EUROFER 97 and ODS-EUROFER steels at elevated temperature

    NASA Astrophysics Data System (ADS)

    Malitckii, Evgenii; Yagodzinskyy, Yuriy; Hänninen, Hannu

    2015-11-01

    The effect of continuous hydrogen charging on tensile properties of EUROFER 97 and ODS-EUROFER steels was studied at room and elevated temperatures of 100 °C and 300 °C. The hydrogen effect decreases with increase of the temperature for ODS-EUROFER steel, while susceptibility to hydrogen of EUROFER 97 steel remains approximately the same at all testing temperatures. Continuous hydrogen charging results in a reduction of the grain boundary cohesion of the EUROFER 97 and ODS-EUROFER steels tested at RT. With increase of the testing temperature up to 300 °C EUROFER 97 steel exhibits relatively high amount of micro-cracks which agglomerate in sub-micrometer size cracks, while the hydrogen-induced intergranular crack nucleation in ODS-EUROFER steel is effectively suppressed. Possible mechanism of the hydrogen-induced crack nucleation and propagation under applied external stress is discussed.

  12. Small, high-pressure liquid hydrogen turbopump

    NASA Technical Reports Server (NTRS)

    Csomor, A.; Sutton, R.

    1977-01-01

    A high pressure, liquid hydrogen turbopump was designed, fabricated, and tested to a maximum speed of 9739 rad/s and a maximum pump discharge pressure of 2861 N/sq. cm. The approaches used in the analysis and design of the turbopump are described, and fabrication methods are discussed. Data obtained from gas generator tests, turbine performance calibration, and turbopump testing are presented.

  13. Temperature dependent dual hydrogen sensor response of Pd nanoparticle decorated Al doped ZnO surfaces

    SciTech Connect

    Gupta, D.; Barman, P. B.; Hazra, S. K.; Dutta, D.; Kumar, M.; Som, T.

    2015-10-28

    Sputter deposited Al doped ZnO (AZO) thin films exhibit a dual hydrogen sensing response in the temperature range 40 °C–150 °C after surface modifications with palladium nanoparticles. The unmodified AZO films showed no response in hydrogen in the temperature range 40 °C–150 °C. The operational temperature windows on the low and high temperature sides have been estimated by isolating the semiconductor-to-metal transition temperature zone of the sensor device. The gas response pattern was modeled by considering various adsorption isotherms, which revealed the dominance of heterogeneous adsorption characteristics. The Arrhenius adsorption barrier showed dual variation with change in hydrogen gas concentration on either side of the semiconductor-to-metal transition. A detailed analysis of the hydrogen gas response pattern by considering the changes in nano palladium due to hydrogen adsorption, and semiconductor-to-metal transition of nanocrystalline Al doped ZnO layer due to temperature, along with material characterization studies by glancing incidence X-ray diffraction, atomic force microscopy, and transmission electron microscopy, are presented.

  14. Rotational relaxation of molecular hydrogen at moderate temperatures

    NASA Technical Reports Server (NTRS)

    Sharma, S. P.

    1994-01-01

    Using a coupled rotation-vibration-dissociation model the rotational relaxation times for molecular hydrogen as a function of final temperature (500-5000 K), in a hypothetical scenario of sudden compression, are computed. The theoretical model is based on a master equation solver. The bound-bound and bound-free transition rates have been computed using a quasiclassical trajectory method. A review of the available experimental data on the rotational relaxation of hydrogen is presented, with a critical overview of the method of measurements and data reduction, including the sources of errors. These experimental data are then compared with the computed results.

  15. High Temperature Superconducting Materials Database

    National Institute of Standards and Technology Data Gateway

    SRD 149 NIST High Temperature Superconducting Materials Database (Web, free access)   The NIST High Temperature Superconducting Materials Database (WebHTS) provides evaluated thermal, mechanical, and superconducting property data for oxides and other nonconventional superconductors.

  16. Magnetic ordering temperature of nanocrystalline Gd: enhancement of magnetic interactions via hydrogenation-induced "negative" pressure.

    PubMed

    Tereshina, E A; Khmelevskyi, S; Politova, G; Kaminskaya, T; Drulis, H; Tereshina, I S

    2016-01-01

    Gadolinium is a nearly ideal soft-magnetic material. However, one cannot take advantage of its properties at temperatures higher than the room temperature where Gd loses the ferromagnetic ordering. By using high-purity bulk samples with grains ~200 nm in size, we present proof-of-concept measurements of an increased Curie point (TC) and spontaneous magnetization in Gd due to hydrogenation. From first-principles we explain increase of TC in pure Gd due to the addition of hydrogen. We show that the interplay of the characteristic features in the electronic structure of the conduction band at the Fermi level in the high-temperature paramagnetic phase of Gd and "negative" pressure exerted by hydrogen are responsible for the observed effect. PMID:26931775

  17. Method and System for the Production of Hydrogen at Reduced VHTR Outlet Temperatures

    SciTech Connect

    Chang H. Oh; Eung S. Kim

    2009-10-01

    The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is two fold 1) efficient low cost energy generation and 2) hydrogen production. Although a next generation plant could be developed as a single-purpose facility dedicated to hydrogen production, early designs are expected to be dual purpose. While hydrogen production and advanced energy cycles are still in its early stages of development, research towards coupling a high temperature reactor with electrical generation and hydrogen production is under way. Many aspects of the NGNP must be researched and developed in order to make recommendations on the final design of the plant. Parameters such as working conditions, cycle components, working fluids, and power conversion unit configurations must be understood. The integrated system of a Very High Temperature Reactor (VHTR) and a High Temperature Steam Electrolysis (HTSE) hydrogen production plant is being investigated and this system, as it is currently envisioned, will produce hydrogen by utilizing a highly efficient VHTR with a VHTR outlet temperature of 900°C to supply the necessary energy and electricity to the HTSE unit. Though the combined system may produce hydrogen and electricity with high efficiency, the choices of materials that are suitable for use at 900°C are limited due to high-temperature strength, corrosion, and durability (creep) considerations. The lack of materials that are ASME (American Society of Mechanical Engineers) code-certified at these temperatures is also a problem, and is a barrier to commercial deployment. If the current system concept can be modified to produce hydrogen with comparable efficiency at lower temperatures, then the technical barriers related to materials selection and use might be eliminated, and the integrated system may have a much greater probability of

  18. In situ study of the fractionation of hydrogen isotopes between aluminosilicate melts and coexisting aqueous fluids at high pressure and high temperature - Implications for the δD in magmatic processes

    NASA Astrophysics Data System (ADS)

    Dalou, Célia; Le Losq, Charles; Mysen, Bjorn O.

    2015-09-01

    The hydrogen isotopic composition of melt inclusions trapped in phenocrysts during their crystallization and growth in a magma may contribute to a better understanding of the water cycle between the atmosphere, the hydrosphere and the lithosphere. Such understanding relies on the knowledge of the hydrogen isotopic fractionation factors between aqueous fluids, silicate melts, and minerals at temperature and pressure conditions relevant to the Earth's interior. Significant D/H fractionation between silicate melts and aqueous fluids was reported at hundreds of MPa and °C by using in situ measurements in hydrothermal diamond anvil cell (HDAC) experiments (Mysen, 2013a, 2013b, Am. Mineral. 98, 376-386 and 1754-1764). However, the available dataset is focused on fluids and melts with D/H ratios close to unity. The relevance of such data for natural processes that involve per mil variations of δD-values may not always be clear. To address such concerns, the effect of the bulk D/H ratio on hydrogen isotope partitioning between water-saturated silicate melts and coexisting silicate-saturated aqueous fluids has been determined in the Na2O-Al2O3-SiO2-H2O-D2O system. To this end, in situ Raman spectroscopic measurements were performed on fluids and melts with bulk D/H ratios from 0.05 to 2.67 by using an externally-heated diamond anvil cell in the 300-800 °C and 200-1500 MPa temperature and pressure range, respectively. In these pressure/temperature ranges, the D/H ratios of fluids in equilibrium with melt barely change with temperature (in average ΔHfluid = 0.47 ± 1.15 kJ /mol). In contrast, the D/H ratios of coexisting melts display strong dependence on temperature (average ΔHmelt = 7.18 ± 1.27 kJ /mol). The temperature-dependence of the D/H fractionation factor between melt and fluid (αfluid-melt = D /Hfluid / D /Hmelt) is comparable in all the experiments and can be written: 1000 ṡ ln ⁡ (αfluid-melt) = 263 (± 26) ṡT-2- 126 (± 48). Therefore, the

  19. HIGH TEMPERATURE SYSTEMS

    DOEpatents

    Thomson, G.P.; Blackman, M.

    1961-07-25

    BS>A device is descrined for producing nuclear fusion reactions by additional acceleration of a hydrogen isotope plasma formed and initially accelerated by a collapsing magnetic field. The plasma is enclosed in a toroidal cavity within a vessel composed of a plurality of insulated coaxial segments. The added acceleration is caused by providing progressing potentials to the insulated segments acting as electrodes by means of a segmented delay transmission line coupled to the electrode segments and excited by a two phase alternating current supply.

  20. High-power CW laser using hydrogen-fluorine reaction

    NASA Technical Reports Server (NTRS)

    Moynihan, P. I.

    1975-01-01

    Continuous-wave laser has been proposed based on reaction of hydrogen and fluorine. Hydrogen is produced by dissociation of hydrazine, which can be stored as liquid in light containers at room temperature.

  1. Temperature dependence of the electrical properties of hydrogen titanate nanotubes

    SciTech Connect

    Alves, Diego C. B.; Brandão, Frederico D.; Krambrock, Klaus; Ferlauto, Andre S.; Fonseca, Fabio C.

    2014-11-14

    The temperature dependence of the electrical properties of hydrogen-rich titanate nanotubes (H-TNTs) in the 90–270 °C range was investigated by impedance spectroscopy. Three types of dominant conduction were found which depend on the previous thermal treatment of the samples. For untreated samples, at low temperatures (T < 100 °C), electrical conductivity is relatively high (>10{sup −4} S/cm at T ≈ 90 °C) and is dominated by protonic transport within structural water molecules. For thermal annealing in inert atmosphere up to 150 °C, water molecules are released from the nanotube structure resulting in a dehydrated H{sub 2}Ti{sub 3}O{sub 7} phase. Such phase has a low, thermally-dependent, electrical conductivity (10{sup −8} S/cm at T ≈ 90 °C) with activation energy of 0.68 eV. For samples annealed up to 260 °C, loss of OH groups, and consequent generation of oxygen vacancies, occurs that result in the non-stoichiometric H{sub 2(1−z)}Ti{sub 3}O{sub 7−z} phase. This phase has much higher conductivity (10{sup −5} S/cm at T ≈ 90 °C) and lower associated activation energy (0.40 eV). The generation of oxygen vacancies is confirmed by electron paramagnetic resonance measurements at room temperature, which revealed the presence of single-electron-trapped oxygen vacancies. The activation energy value found is consistent with the thermal ionization energy of the oxygen vacancies. Such defect formation represents the initial stage of the phase transformation from titanate to TiO{sub 2} (B). X-ray diffraction and Raman spectroscopy measurements also support such interpretation.

  2. Empirical Method to Estimate Hydrogen Embrittlement of Metals as a Function of Hydrogen Gas Pressure at Constant Temperature

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A.

    2010-01-01

    High pressure Hydrogen (H) gas has been known to have a deleterious effect on the mechanical properties of certain metals, particularly, the notched tensile strength, fracture toughness and ductility. The ratio of these properties in Hydrogen as compared to Helium or Air is called the Hydrogen Environment Embrittlement (HEE) Index, which is a useful method to classify the severity of H embrittlement and to aid in the material screening and selection for safety usage H gas environment. A comprehensive world-wide database compilation, in the past 50 years, has shown that the HEE index is mostly collected at two conveniently high H pressure points of 5 ksi and 10 ksi near room temperature. Since H embrittlement is directly related to pressure, the lack of HEE index at other pressure points has posed a technical problem for the designers to select appropriate materials at a specific H pressure for various applications in aerospace, alternate and renewable energy sectors for an emerging hydrogen economy. Based on the Power-Law mathematical relationship, an empirical method to accurately predict the HEE index, as a function of H pressure at constant temperature, is presented with a brief review on Sievert's law for gas-metal absorption.

  3. Low temperature exfoliation process in hydrogen-implanted germanium layers

    NASA Astrophysics Data System (ADS)

    Ferain, I. P.; Byun, K. Y.; Colinge, C. A.; Brightup, S.; Goorsky, M. S.

    2010-03-01

    The feasibility of transferring hydrogen-implanted germanium to silicon with a reduced thermal budget is demonstrated. Germanium samples were implanted with a splitting dose of 5×1016 H2+ cm-2 at 180 keV and a two-step anneal was performed. Surface roughness and x-ray diffraction pattern measurements, combined with cross-sectional TEM analysis of hydrogen-implanted germanium samples were carried out in order to understand the exfoliation mechanism as a function of the thermal budget. It is shown that the first anneal performed at low temperature (≤150 °C for 22 h) enhances the nucleation of hydrogen platelets significantly. The second anneal is performed at 300 °C for 5 min and is shown to complete the exfoliation process by triggering the formation of extended platelets. Two key results are highlighted: (i) in a reduced thermal budget approach, the transfer of hydrogen-implanted germanium is found to follow a mechanism similar to the transfer of hydrogen-implanted InP and GaAs, (ii) such a low thermal budget (<300 °C) is found to be suitable for directly bonded heterogeneous substrates, such as germanium bonded to silicon, where different thermal expansion coefficients are involved.

  4. Fluid hydrogen at high density - The plasma phase transition

    NASA Technical Reports Server (NTRS)

    Saumon, D.; Chabrier, G.

    1989-01-01

    A new model equation of state is applied, based on realistic interparticle potentials and a self-consistent treatment of the internal levels, to fluid hydrogen at high density. This model shows a strong connection between molecular dissociation and pressure ionization. The possibility of a first-order plasma phase transition is considered, and for which both the evolution in temperature and the critical point is given.

  5. Temperature enhancement of secondary electron emission from hydrogenated diamond films

    SciTech Connect

    Stacey, A.; Prawer, S.; Rubanov, S.; Akhvlediani, R.; Michaelson, Sh.; Hoffman, A.

    2009-09-15

    The effect of temperature on the stability of the secondary electron emission (SEE) yield from approx100-nm-thick continuous diamond films is reported. At room temperature, the SEE yield was found to decay as a function of electron irradiation dose. The SEE yield is observed to increase significantly upon heating of the diamond surface. Furthermore, by employing moderate temperatures, the decay of the SEE yield observed at room temperature is inhibited, showing a nearly constant yield with electron dose at 200 deg. C. The results are explained in terms of the temperature dependence of the electron beam-induced hydrogen desorption from the diamond surface and surface band bending. These findings demonstrate that the longevity of diamond films in practical applications of SEE can be increased by moderate heating.

  6. Effect of temperature and temperature shock on the stability of continuous cellulosic-hydrogen fermentation.

    PubMed

    Gadow, Samir I; Jiang, Hongyu; Watanabe, Ryoya; Li, Yu-You

    2013-08-01

    Three continuous stirred tank reactors (CSTR) were operated under mesophilic (37 ± 1°C), thermophilic (55 ± 1°C) and hyper-thermophilic (80 ± 1°C) temperatures for 164 days to investigate the effect of temperature and temperature shock on the cellulosic-dark hydrogen fermentation by mixed microflora. During steady state condition, the sudden decreases in the fermentation temperature occurred twice in each condition for 24h. The results show that the 55 ± 1 and 80 ± 1°C presented stable hydrogen yields of 12.28 and 9.72 mmol/g cellulose, respectively. However, the 37 ± 1°C presented low hydrogen yield of 3.56 mmol/g cellulose and methane yield of 5.4 mmol/g cellulose. The reactor performance under 55 ± 1 or 80 ± 1°C appeared to be more resilient to the sudden decreases in the fermentation temperature than 37 ± 1°C. The experimental analysis results indicated that the changing in soluble by-products could explain the effect of temperature and temperature shock, and the thermophilic temperature is expected having a better economic performance for cellulosic-hydrogen fermentation. PMID:23747441

  7. Solar hydrogen by thermochemical water splitting cycles: design, modeling, and demonstration of a novel receiver/reactor for the high temperature decomposition of zno using concentrated sunlight

    NASA Astrophysics Data System (ADS)

    Kaiser, Zachary David Epping

    Documenting the presence of rare bat species can be difficult. The current summer survey protocol for the federally endangered Indiana bat ( Myotis sodalis) requires passive acoustic sampling with directional microphones (e.g., Anabats), but there are still questions about best practices for choosing survey sites and appropriate detector models. Indiana bats are capable of foraging in an array of cover types, including structurally-complex, interior forests. Further, data acquisition among different commercially available bat detectors is likely highly variable, due to the use of proprietary microphones with different frequency responses, sensitivities, and directionality. We paired omnidirectional Wildlife Acoustic SM2BAT+ (SM2) and directional Titley Scientific Anabat SD2 (Anabat) detectors at 71 random points near Indianapolis, Indiana from May-August 2012-2013 to compare data acquisition by phonic group (low, mid, Myotis) and to determine what factors affect probability of detection and site occupancy for Indiana bats when sampling with acoustics near an active maternity colony (0.20--8.39 km away). Weatherproofing for Anabat microphones was 45° angle PVC tubes and for SM2 microphones was their foam shielding; microphones were paired at 2 m and 5 m heights. Habitat and landscape covariates were measured in the field or via ArcGIS. We adjusted file parameters to make SM2 and Anabat data comparable. Files were identified using Bat Call ID software, with visual inspection of Indiana bat calls. The effects of detector type, phonic group, height, and their interactions on mean files recorded per site were assessed using generalized estimating equations and LSD pairwise comparisons. We reduced probability of detection (p) and site occupancy (ψ) model covariates with Pearson's correlation and PCA. We used Presence 6.1 software and Akaike's Information Criteria to assess models for p and ψ. Anabats and SM2s did not perform equally. Anabats recorded more low and

  8. High temperature lubricating process

    DOEpatents

    Taylor, R.W.; Shell, T.E.

    1979-10-04

    It has been difficult to provide adequate lubrication for load bearing, engine components when such engines are operating in excess of about 475/sup 0/C. The present invention is a process for providing a solid lubricant on a load bearing, solid surface, such as in an engine being operated at temperatures in excess of about 475/sup 0/C. The process comprises contacting and maintaining the following steps: a gas phase is provided which includes at least one component reactable in a temperature dependent reaction to form a solid lubricant; the gas phase is contacted with the load bearing surface; the load bearing surface is maintained at a temperature which causes reaction of the gas phase component and the formation of the solid lubricant; and the solid lubricant is formed directly on the load bearing surface. The method is particularly suitable for use with ceramic engines.

  9. High-Temperature Piezoelectric Sensing

    PubMed Central

    Jiang, Xiaoning; Kim, Kyungrim; Zhang, Shujun; Johnson, Joseph; Salazar, Giovanni

    2014-01-01

    Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented. PMID:24361928

  10. High-temperature bearing lubricants

    NASA Technical Reports Server (NTRS)

    Anderson, W. J.; Parker, R. J.; Zaretsky, E. V.

    1968-01-01

    Synthetic paraffinic oil lubricates ball bearings at temperatures in the 600 degrees F range. The lubricant contains antiwear and antifoam additives, is thermally stable in the high temperature range, but requires protection from oxygen.

  11. High pressure hydrogen time projection chamber

    SciTech Connect

    Goulianos, K.

    1983-01-01

    We describe a high pressure hydrogen gas time projection chamber which consists of two cylindrical drift regions each 45 cm in diameter and 75 cm long. Typically, at 15 atm of H/sub 2/ with 2 kV/cm drift field and 7 kV on the 35..mu.. sense wires, the drift velocity is about 0.5 cm/..mu..sec and the spatial resolution +-200..mu...

  12. Small, high pressure liquid hydrogen turbopump

    NASA Technical Reports Server (NTRS)

    Csomor, A.; Warren, D. J.

    1980-01-01

    A high pressure, low capacity, liquid hydrogen turbopump was designed, fabricated, and tested. The design configuration of the turbopump is summarized and the results of the analytical and test efforts are presented. Approaches used to pin point the cause of poor suction performance with the original design are described and performance data are included with an axial inlet design which results in excellent suction capability.

  13. Molecular hydrogen emission as a density and temperature indicator

    NASA Astrophysics Data System (ADS)

    Wang, Xiang; Ferland, Gary J.; Baldwin, Jack A.; Loh, Edwin D.; Fabian, Andy C.; Williams, Robin

    2016-01-01

    Infrared observations have discovered a variety of objects, including filaments in the Crab Nebula and cool-core clusters of galaxies, where the 1-0 S(1) line is stronger than the infrared H I lines. A variety of processes could be responsible for this emission. Although many complete shock or PDR calculations of emission have been published, we know of no previous simple calculation that shows the emission spectrum and level populations of thermally excited low-density . We present a range of purely thermal collisional simulations, corresponding to constant gas kinetic temperature at different densities. We consider the cases where the collisions affecting H2 are predominantly with atomic or molecular hydrogen. The resulting level population (often called "excitation") diagrams show that excitation temperatures are sometimes lower than the gas kinetic temperature when the density is too low for the level populations to go to LTE. The atomic case goes to LTE at much lower densities than the molecular case due to larger collision rates. At low densities for the v=1 and 2 vibrational manifolds level populations are quasi-thermal, which could be misinterpreted as showing the gas is in LTE at high density. At low densities for the molecular case the level population diagrams are discontinuous between v=0 and 1 vibrational manifolds and between v=2, J=0, 1 and other higher J levels within the same vibrational manifold. These jumps could be used as density diagnostics. We show how much the H2 mass would be underestimated using the 1-0 S(1) line strength if the density is below that required for LTE. We give diagnostic diagrams showing level populations over a range of density and temperature. The density where the level populations are given by a Boltzmann distribution relative to the total molecular abundance (required to get the correct H2 mass), is shown for various cases. We discuss the implications of these results for the interpretation of H2 observations of the

  14. Measurement and Calculation of Electrochemical Potentials in Hydrogenated High Temperature Water, including an Evaluation of the Yttria-Stabilized Zirconia/Iron-Iron Oxide (Fe/Fe3O4) Probe as Reference Electrode

    SciTech Connect

    Steven A. Attanasio; David S. Morton; Mark A. Ando

    2001-10-22

    The importance of knowing the electrochemical corrosion potential (ECP, also referred to as E{sub con}) of nickel-base alloys in hydrogenated water is related to the need to understand the effects of dissolved (i.e., aqueous) hydrogen concentration ([H{sub 2}]) on primary water stress corrosion cracking (PWSCC). Also, the use of a reference electrode (RE) can improve test quality by heightening the ability to detect instances of out-of-specification or unexpected chemistry. Three methods are used to measure and calculate the ECP of nickel-based alloys in hydrogenated water containing {approx} 1 to 150 scc/kg H{sub 2} (0.1 to 13.6 ppm H{sub 2}) at 260 to 360 C. The three methods are referred to as the specimen/component method, the platinum (Pt) method, and the yttria-stabilized zirconia/iron-iron oxide (YSZ/Fe-Fe{sub 3}O{sub 4}) RE method. The specimen/component method relies upon the assumption that the specimen or component behaves as a hydrogen electrode, and its E{sub corr} is calculated using the Nernst equation. The present work shows that this method is valid for aqueous H{sub 2} levels {ge} {approx} 5 to 10 scc/kg H{sub 2}. The Pt method uses a voltage measurement between the specimen or component and a Pt electrode, with the Pt assumed to behave as a hydrogen electrode; this method is valid as long as the aqueous H{sub 2}level is known. The YSZ/Fe-Fe{sub 3}O{sub 4}, which represents a relatively new approach for measuring E{sub corr} in this environment, can be used even if the aqueous H{sub 2} level is unknown. The electrochemical performance of the YSZ/Fe-Fe{sub 3}O{sub 4} probe supports its viability as a RE for use in high temperature hydrogenated water. Recent design modifications incorporating a teflon sealant have improved the durability of this RE (however, some of the REs do still fail prematurely due to water in-leakage). The Pt method is judged to represent the best overall approach, though there are cases where the other methods are superior

  15. Controlled thermonuclear fusion, high temperature plasma physics

    NASA Astrophysics Data System (ADS)

    1985-05-01

    The primary source of nuclear energy comes from the fission process of heavy nuclei. To utilize the energy released by a thermonuclear fusion process, methods of controlling the fusion reaction were studied. This is controlled thermonuclear fusion technology. The fuel used in a thermonuclear fusion process are isotopes of hydrogen: deuterium and tritium. They can be extracted from the almost unlimited seawater. Nuclear fusion also produces very little radioactive waste. Thermonuclear fusion is a promising energy source with an almost unlimited supply; it is economical, safe, and relatively clean. Ways to raise plasma temperature to a very high level and to maintain it to allow fusion reactions to take place are studied. The physical laws of high temperature plasma was studied to reach this goal which resulted in the development of high temperature plasma physics.

  16. Numerical Simulation of a Hydrogen MPD Thruster with Temperature Nonequilibrium

    NASA Astrophysics Data System (ADS)

    Sato, Hiroki; Kubota, Kenichi; Funaki, Ikkoh

    Plasma flowfields and performances of an MPD thruster (MY-II thruster), which uses hydrogen as a propellant, are studied by solving axi-symmetrical two-dimensional magnetoplasmadynamic equations. The three-temperature model including the translation Ttr, vibration Tvib, and electron Te temperatures is incorporated into the flow solver. When the mass flow rate (m) is 1.37g/s, there is reasonable agreement on the thrust with measured data, especially at a discharge current (Jdis) of 7, 8kA. Under the conditions of m = 0.4g/s and Jdis = 5kA, the calculated thrust, specific impulse and thrust efficiency are 7.50N, 1,911s and 21.3% (without considering sheath voltage drop), respectively. The calculated flow shows a temperature nonequilibrium state (Te = 2.53eV, Tvib = 1.32eV, Ttr = 0.60eV) at the edge of the straight part, and it is found that the relaxation time between the vibration and the electron energy is equal to the characteristic time of the flow at (z, r) = (30mm, 20mm). Along the symmetrical axis, the dissociation and ionization fractions reach 1.0 (fully dissociation) and 0.2, respectively. Because the discharge current path by the three-temperature model can explain the important feature of hydrogen MPD (current expansion to the downstream), it is concluded that the three-temperature model can reproduce the experimental results.

  17. High temperature LSI

    NASA Technical Reports Server (NTRS)

    Dening, D. C.; Ragonese, L. J.; Lee, C. Y.

    1982-01-01

    Integrated injection logic (1,2) technology for reliable operation under a -55 C to +300 C, temperature range is discussed. Experimental measurements indicate that an 80 mv signal swing is available at 300 C with 100 micro A injection current per gate. In addition, modeling results predict how large gate fan-ins can decrease the maximum thermal operational limits. These operational limits and the longterm reliability factors associated with device metallization are evaluated via specialized test mask.

  18. Isotopic effect and amorphization of deuterated hydrogen hydrate under high pressure

    NASA Astrophysics Data System (ADS)

    Machida, Shin-Ichi; Hirai, Hisako; Kawamura, Taro; Yamamoto, Yoshitaka; Yagi, Takehiko

    2011-04-01

    High-pressure experiments of a mixture of H2 and D2O were performed using a diamond-anvil cell in the pressure range of 0.5-77.0 GPa under room temperature. Raman measurements revealed that an exchange of the hydrogen atoms occurred between fluid hydrogen and liquid water before the formation of deuterated hydrogen hydrate, and that a high-pressure structure of hydrogen hydrate, a filled ice Ic structure, formed at the same pressure as H2-H2O system hydrate. Additionally, the Raman spectra of the vibron for the D2, HD and H2 molecules revealed that the guest hydrogen molecules were partly extracted from the filled ice Ic structure above 20 GPa. The extraction of hydrogen molecules occurred depending on the atomic weight of the guest hydrogen molecules, and the heavier molecules were selectively released from the filled ice Ic structure. This isotopic effect in the extraction of hydrogen molecules showed differences in the stability of hydrogen hydrate depending on the species of guest molecules between D2, HD, and H2. Above 65 GPa, the filled ice Ic structure of hydrogen hydrate transformed to an amorphous phase. Formation of the amorphous phase showed the high-pressure limitation of hydrogen hydrate as a crystal structure and a new mechanism for the dissociation of gas hydrates under high pressure and room temperature.

  19. Temperature-dependent absorption cross sections for hydrogen peroxide vapor

    NASA Technical Reports Server (NTRS)

    Nicovich, J. M.; Wine, P. H.

    1988-01-01

    Relative absorption cross sections for hydrogen peroxide vapor were measured over the temperature ranges 285-381 K for lambda = 230 nm-295 nm and 300-381 K for lambda = 193 nm-350 nm. The well established 298 K cross sections at 202.6 and 228.8 nm were used as an absolute calibration. A significant temperature dependence was observed at the important tropospheric photolysis wavelengths lambda over 300 nm. Measured cross sections were extrapolated to lower temperatures, using a simple model which attributes the observed temperature dependence to enhanced absorption by molecules possessing one quantum of O-O stretch vibrational excitation. Upper tropospheric photodissociation rates calculated using the extrapolated cross sections are about 25 percent lower than those calculated using currently recommended 298 K cross sections.

  20. Temperature dependence of hydrogenated amorphous silicon solar cell performances

    NASA Astrophysics Data System (ADS)

    Riesen, Y.; Stuckelberger, M.; Haug, F.-J.; Ballif, C.; Wyrsch, N.

    2016-01-01

    Thin-film hydrogenated amorphous silicon solar (a-Si:H) cells are known to have better temperature coefficients than crystalline silicon cells. To investigate whether a-Si:H cells that are optimized for standard conditions (STC) also have the highest energy yield, we measured the temperature and irradiance dependence of the maximum power output (Pmpp), the fill factor (FF), the short-circuit current density (Jsc), and the open-circuit voltage (Voc) for four series of cells fabricated with different deposition conditions. The parameters varied during plasma-enhanced chemical vapor deposition (PE-CVD) were the power and frequency of the PE-CVD generator, the hydrogen-to-silane dilution during deposition of the intrinsic absorber layer (i-layer), and the thicknesses of the a-Si:H i-layer and p-type hydrogenated amorphous silicon carbide layer. The results show that the temperature coefficient of the Voc generally varies linearly with the Voc value. The Jsc increases linearly with temperature mainly due to temperature-induced bandgap reduction and reduced recombination. The FF temperature dependence is not linear and reaches a maximum at temperatures between 15 °C and 80 °C. Numerical simulations show that this behavior is due to a more positive space-charge induced by the photogenerated holes in the p-layer and to a recombination decrease with temperature. Due to the FF(T) behavior, the Pmpp (T) curves also have a maximum, but at a lower temperature. Moreover, for most series, the cells with the highest power output at STC also have the best energy yield. However, the Pmpp (T) curves of two cells with different i-layer thicknesses cross each other in the operating cell temperature range, indicating that the cell with the highest power output could, for instance, have a lower energy yield than the other cell. A simple energy-yield simulation for the light-soaked and annealed states shows that for Neuchâtel (Switzerland) the best cell at STC also has the best energy

  1. Zero-Temperature Structures of Atomic Metallic Hydrogen

    NASA Astrophysics Data System (ADS)

    McMahon, Jeffrey; Ceperley, David

    2011-03-01

    Since the first prediction of an atomic metallic phase of hydrogen by Wigner and Huntington over 75 years ago, there have been many theoretical efforts aimed at determining the crystal structures of the zero-temperature phases. We present results from ab initio random structure searching with density functional theory performed to determine the ground state structures from 500 GPa to 5 TPa. We estimate that molecular hydrogen dissociates into a monatomic body-centered tetragonal structure near 500 GPa (rs = 1.225), which then remains stable to 2.5 TPa (rs = 0.969). At higher pressures, hydrogen stabilizes in an . . . ABCABC . . . planar structure that is remarkably similar to the ground state of lithium, which compresses to the face-centered cubic lattice beyond 5 TPa (rs < 0.86). Our results provide a complete ab initio description of the atomic metallic crystal structures of hydrogen, resolving one of the most fundamental and long outstanding issues concerning the structures of the elements.

  2. Multilayer graphane synthesized under high hydrogen pressure

    DOE PAGESBeta

    Antonov, V. E.; Bashkin, I. O.; Bazhenov, A. V.; Bulychev, B. M.; Fedotov, V. K.; Fursova, T. N.; Kolesnikov, A. I.; Kulakov, V. I.; Lukashev, R. V.; Matveev, D. V.; et al

    2015-12-19

    A new hydrocarbon – hydrographite – with the composition close to CH is shown to form from graphite and gaseous hydrogen at pressures above 2 GPa and temperatures from 450 to 700 °C. Hydrographite is a black solid thermally stable under ambient conditions. When heated in vacuum, it decomposes into graphite and molecular hydrogen at temperatures from 500 to 650 °C. Powder X-ray diffraction characterizes hydrographite as a multilayer “graphane II” phase predicted by ab initio calculations [Wen X-D et al. PNAS 2011; 108:6833] and consisting of graphane sheets in the chair conformation stacked along the hexagonal c axis inmore » the -ABAB- sequence. The crystal structure of the synthesized phase belongs to the P63mc space group. Moreover, the unit cell parameters are a = 2.53(1) Å and c = 9.54(1) Å and therefore exceed the corresponding parameters of graphite by 2.4(2)% and 42.0(3)%. Stretching vibrations of C–H groups on the surface of the hydrographite particles are examined by infrared spectroscopy.« less

  3. Multilayer graphane synthesized under high hydrogen pressure

    SciTech Connect

    Antonov, V. E.; Bashkin, I. O.; Bazhenov, A. V.; Bulychev, B. M.; Fedotov, V. K.; Fursova, T. N.; Kolesnikov, A. I.; Kulakov, V. I.; Lukashev, R. V.; Matveev, D. V.; Sakharov, M. K.; Shulga, Y. M.

    2015-12-19

    A new hydrocarbon – hydrographite – with the composition close to CH is shown to form from graphite and gaseous hydrogen at pressures above 2 GPa and temperatures from 450 to 700 °C. Hydrographite is a black solid thermally stable under ambient conditions. When heated in vacuum, it decomposes into graphite and molecular hydrogen at temperatures from 500 to 650 °C. Powder X-ray diffraction characterizes hydrographite as a multilayer “graphane II” phase predicted by ab initio calculations [Wen X-D et al. PNAS 2011; 108:6833] and consisting of graphane sheets in the chair conformation stacked along the hexagonal c axis in the -ABAB- sequence. The crystal structure of the synthesized phase belongs to the P63mc space group. Moreover, the unit cell parameters are a = 2.53(1) Å and c = 9.54(1) Å and therefore exceed the corresponding parameters of graphite by 2.4(2)% and 42.0(3)%. Stretching vibrations of C–H groups on the surface of the hydrographite particles are examined by infrared spectroscopy.

  4. Manufacture of high purity low arsenic anhydrous hydrogen fluoride

    SciTech Connect

    Jenczewski, T.J.; Sturtevant, R.L.; Morgan, T.R.; Boghean, B.J.; Butt, D.C.

    1988-07-12

    A process for manufacturing anhydrous hydrogen fluoride with reduced levels of arsenic impurity from arsenic contaminated anhydrous hydrogen fluoride is described which comprises: (a) contacting the anhydrous hydrogen fluoride with an effective amount of hydrogen peroxide to oxidize the arsenic impurity in the presence of a catalyst which comprises a catalytic amount of (i) molybdenum or an inorganic molybdenum compound and (ii) a phosphate compound, at a temperature and for a period of time sufficient to oxidize volatile trivalent arsenic impurities in the anhydrous hydrogen fluoride to non-volatile pentavalent arsenic compounds, and (b) distilling the resulting mixture and recovering anhydrous hydrogen fluoride with reduced levels of arsenic impurity.

  5. Materials Compatibility in High Test Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Gostowski, Rudy

    1999-01-01

    Previous ratings of the compatibility of high test hydrogen peroxide (HTP) with materials are not adequate for current needs. The goal of this work was to develop a new scheme of evaluation of compatibility of HTP with various materials. Procedures were developed to enrich commercially available hydrogen peroxide to 90% concentration and to assay the product. Reactivity testing, accelerated aging of materials and calorimetry studies were done on HTP with representative metallic and non-metallic materials. It was found that accelerated aging followed by concentration determination using refractive index effectively discriminated between different Class 2 metallic materials. Preliminary experiments using Differential Scanning Calorimetry (DSC) suggest that a calorimetry experiment is the most sensitive means to assay the compatibility of HTP with materials.

  6. 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.

  7. Liquid Fuel Production from Biomass via High Temperature Steam Electrolysis

    SciTech Connect

    Grant L. Hawkes; Michael G. McKellar

    2009-11-01

    A process model of syngas production using high temperature electrolysis and biomass gasification is presented. Process heat from the biomass gasifier is used to heat steam for the hydrogen production via the high temperature steam electrolysis process. Hydrogen from electrolysis allows a high utilization of the biomass carbon for syngas production. Oxygen produced form the electrolysis process is used to control the oxidation rate in the oxygen-fed biomass gasifier. Based on the gasifier temperature, 94% to 95% of the carbon in the biomass becomes carbon monoxide in the syngas (carbon monoxide and hydrogen). Assuming the thermal efficiency of the power cycle for electricity generation is 50%, (as expected from GEN IV nuclear reactors), the syngas production efficiency ranges from 70% to 73% as the gasifier temperature decreases from 1900 K to 1500 K. Parametric studies of system pressure, biomass moisture content and low temperature alkaline electrolysis are also presented.

  8. Premixer Design for High Hydrogen Fuels

    SciTech Connect

    Benjamin P. Lacy; Keith R. McManus; Balachandar Varatharajan; Biswadip Shome

    2005-12-16

    This 21-month project translated DLN technology to the unique properties of high hydrogen content IGCC fuels, and yielded designs in preparation for a future testing and validation phase. Fundamental flame characterization, mixing, and flame property measurement experiments were conducted to tailor computational design tools and criteria to create a framework for predicting nozzle operability (e.g., flame stabilization, emissions, resistance to flashback/flame-holding and auto-ignition). This framework was then used to establish, rank, and evaluate potential solutions to the operability challenges of IGCC combustion. The leading contenders were studied and developed with the most promising concepts evaluated via computational fluid dynamics (CFD) modeling and using the design rules generated by the fundamental experiments, as well as using GE's combustion design tools and practices. Finally, the project scoped the necessary steps required to carry the design through mechanical and durability review, testing, and validation, towards full demonstration of this revolutionary technology. This project was carried out in three linked tasks with the following results. (1) Develop conceptual designs of premixer and down-select the promising options. This task defined the ''gap'' between existing design capabilities and the targeted range of IGCC fuel compositions and evaluated the current capability of DLN pre-mixer designs when operated at similar conditions. Two concepts (1) swirl based and (2) multiple point lean direct injection based premixers were selected via a QFD from 13 potential design concepts. (2) Carry out CFD on chosen options (1 or 2) to evaluate operability risks. This task developed the leading options down-selected in Task 1. Both a GE15 swozzle based premixer and a lean direct injection concept were examined by performing a detailed CFD study wherein the aerodynamics of the design, together with the chemical kinetics of the combustion process, were

  9. High-temperature-measuring device

    DOEpatents

    Not Available

    1981-01-27

    A temperature measuring device for very high design temperatures (to 2000/sup 0/C) is described. The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells. The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensonally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured. Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions.

  10. Influence of hydrogen bonds and temperature on dielectric properties.

    PubMed

    Ortiz de Urbina, Jordi; Sesé, Gemma

    2016-07-01

    Dielectric properties are evaluated by means of molecular dynamics simulations on two model systems made up of dipolar molecules. One of them mimics methanol, whereas the other differs from the former only in the ability to form hydrogen bonds. Static dielectric properties such as the permittivity and the Kirkwood factor are evaluated, and results are analyzed by considering the distribution of relative orientations between molecular dipoles. Dipole moment-time correlation functions are also evaluated. The relevance of contributions associated with autocorrelations of molecular dipoles and with cross-correlations between dipoles belonging to different molecules has been investigated. For methanol, the Debye approximation for the overall dipole moment correlation function is not valid at room temperature. The model applies when hydrogen bonds are suppressed, but it fails upon cooling the nonassociated liquid. Important differences between relaxation times associated with dipole auto- versus cross-correlations as well as their relative relevance are at the root of the Debye model breakdown. PMID:27575177

  11. Azimuthal and Temperature Dependence of Hydrogen on Nickel (111)

    NASA Astrophysics Data System (ADS)

    Nabighian, Edward; Zhu, X. D.

    1998-03-01

    Using a linear optical diffraction technique, we measure the temperature and azimuthal dependence of hydrogen diffusion rate on a nickel (111) surface with a miscut angle of less than 0.1 degrees. In the classical over-barrier hopping regime, the diffusion barrier over flat terraces is found to be 4.5 kcal/mol. From the azimuthal dependence, we found the barrier crossing a step edge is no more than 6.0 kcal/mol. This indicates that the step edge barrier, known as a Schwoebal-Erlich barrier, for hydrogen on nickel (111) is less than 1.5 kcal/mol or 30 percent of the barrier over flat terraces.

  12. Influence of hydrogen bonds and temperature on dielectric properties

    NASA Astrophysics Data System (ADS)

    Ortiz de Urbina, Jordi; Sesé, Gemma

    2016-07-01

    Dielectric properties are evaluated by means of molecular dynamics simulations on two model systems made up of dipolar molecules. One of them mimics methanol, whereas the other differs from the former only in the ability to form hydrogen bonds. Static dielectric properties such as the permittivity and the Kirkwood factor are evaluated, and results are analyzed by considering the distribution of relative orientations between molecular dipoles. Dipole moment-time correlation functions are also evaluated. The relevance of contributions associated with autocorrelations of molecular dipoles and with cross-correlations between dipoles belonging to different molecules has been investigated. For methanol, the Debye approximation for the overall dipole moment correlation function is not valid at room temperature. The model applies when hydrogen bonds are suppressed, but it fails upon cooling the nonassociated liquid. Important differences between relaxation times associated with dipole auto- versus cross-correlations as well as their relative relevance are at the root of the Debye model breakdown.

  13. Selective hydrogen purification through graphdiyne under ambient temperature and pressure.

    PubMed

    Cranford, Steven W; Buehler, Markus J

    2012-08-01

    Graphdiyne, a recently synthesized one-atom-thick carbon allotrope, is atomistically porous - characterized by a regular "nanomesh"- and suggests application as a separation membrane for hydrogen purification. Here we report a full atomistic reactive molecular dynamics investigation to determine the selective diffusion properties of hydrogen (H(2)) amongst carbon monoxide (CO) and methane (CH(4)), a mixture otherwise known as syngas, a product of the gasification of renewable biomass (such as animal wastes). Under constant temperature simulations, we find the mass flux of hydrogen molecules through a graphdiyne membrane to be on the order of 7 to 10 g cm(-2) s(-1) (between 300 K and 500 K), with carbon monoxide and methane remaining isolated. Using a simple Arrhenius relation, we determine the energy required for permeation on the order of 0.11 ± 0.03 eV for single H(2) molecules. We find that addition of marginal applied force (approximately 1 to 2 pN per molecule, representing a controlled pressure gradient, ΔP, on the order of 100 to 500 kPa) can successfully enhance the separation of hydrogen gas. Addition of larger driving forces (50 to 100 pN per molecule) is required to selectively filter carbon monoxide or methane, suggesting that, under near-atmospheric conditions, only hydrogen gas will pass such a membrane. Graphdiyne provides a unique, chemically inert and mechanically stable platform facilitating selective gas separation at nominal pressures using a homogeneous material system, without a need for chemical functionalization or the explicit introduction of molecular pores. PMID:22706782

  14. Mechanical properties of several nickel alloys in hydrogen at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Warren, J. R.; Harris, J. A., Jr.; Vanwanderham, M. C.

    1977-01-01

    Tests were performed to determine low cycle fatigue and crack growth rate properties of one iron-base and two forms of one cast nickel-base alloy. The alloys were tested in various forms and/or heat-treat conditions that are proposed for use in a high-pressure hydrogen or a hydrogen-water vapor environment. Some general conclusions can be made comparing the results of tests in a hydrogen environment with those in a hydrogen-water vapor environment. The hydrogen-water vapor environment caused a 50 percent average reduction in fatigue life, indicating extreme degradation when compared with tests conducted in air, for Incoloy 903 at 1033 K (1400 F). Crack growth rates increased significantly for all materials with increasing test temperature. A very significant increase (three orders of magnitude) in crack growth rate occurred for Incoloy 903 tested in the hydrogen-water vapor environment when compared with testing done in hydrogen along at 922 K (1200 F).

  15. High temperature interface superconductivity

    DOE PAGESBeta

    Gozar, A.; Bozovic, I.

    2016-01-20

    High-Tc superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-Tc Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both ‘passive’ hetero-structures as well as surface-induced effects by external gating are discussed. Here, wemore » conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.« less

  16. High temperature interface superconductivity

    NASA Astrophysics Data System (ADS)

    Gozar, A.; Bozovic, I.

    2016-02-01

    High-Tc superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-Tc Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both 'passive' hetero-structures as well as surface-induced effects by external gating are discussed. We conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.

  17. Analyzing the effects of temperature on soot formation with a joint volume-surface-hydrogen model

    SciTech Connect

    Blanquart, G.; Pitsch, H.

    2009-08-15

    The intent of the current work is to present and further validate a new tri-variate model for the formation of soot particles, to apply this model in analyzing the effects of temperature on the formation and growth of soot, and to compare the findings with the present understanding derived from numerous experimental studies. In this novel model, a particle is represented as a fractal shaped aggregate and is described by three independent quantities: the volume, the surface area, and the number of hydrogenated sites (or active sites) on the surface. The introduction of this third variable allows for a better description of the surface reactivity at high temperatures. This approach is extended by a model for the total carbon-to-hydrogen (C/H) ratio of the particle. The model is validated first in high temperature premixed ethylene flames, premixed benzene flames, an acetylene counterflow diffusion flame, and toluene pyrolysis in shock-tubes. Then, the soot volume fraction is computed for a series of atmospheric laminar ethylene premixed flames with varying flame temperatures. The soot model is shown to reproduce the well known bell-shaped temperature dependence of soot volume fraction, which was found in many experiments. It is observed that nucleation is the largest contributor to soot volume fraction at low temperatures while growth by surface reactions is more important at higher temperatures. The surface reactivity and the volumetric carbon-to-hydrogen ratio (C/H) are also computed as a function of temperature. The surface reactivity is found to depend not only on the temperature but also on the particle size and the residence time in the flame. Finally, as observed experimentally, the C/H ratio is found to be essentially constant and close to unity for low temperature flames and increases with residence time in high temperature flames. (author)

  18. High specific energy, high capacity nickel-hydrogen cell design

    NASA Technical Reports Server (NTRS)

    Wheeler, James R.

    1993-01-01

    A 3.5 inch rabbit-ear-terminal nickel-hydrogen cell has been designed and tested to deliver high capacity at a C/1.5 discharge rate. Its specific energy yield of 60.6 wh/kg is believed to be the highest yet achieved in a slurry-process nickel-hydrogen cell, and its 10 C capacity of 113.9 AH the highest capacity yet made at a discharge rate this high in the 3.5 inch diameter size. The cell also demonstrated a pulse capability of 180 amps for 20 seconds. Specific cell parameters, performance, and future test plans are described.

  19. High-temperature ceramic receivers

    SciTech Connect

    Jarvinen, P. O.

    1980-01-01

    An advanced ceramic dome cavity receiver is discussed which heats pressurized gas to temperatures above 1800/sup 0/F (1000/sup 0/C) for use in solar Brayton power systems of the dispersed receiver/dish or central receiver type. Optical, heat transfer, structural, and ceramic material design aspects of the receiver are reported and the development and experimental demonstration of a high-temperature seal between the pressurized gas and the high-temperature silicon carbide dome material is described.

  20. High performance hydrogen-terminated diamond field effect transistors

    NASA Astrophysics Data System (ADS)

    Russell, Stephen A. O.

    Diamond provides extreme properties which make it suitable as a new substrate material for high performance electronics. It has the potential to provide both high frequency and high power performance while operating in extreme environments such as elevated temperature or exposed to corrosive chemicals or radiation. Research to date has shown the potential of diamond for this purpose with hydrogen-terminated diamond surface channel transistors already showing promise in terms of high frequency operation. The inherent instability of using atmospheric molecules to induce a p-type doping at this hydrogen-terminated diamond surface has so far limited power performance and robustness of operation. This work reports upon the scaling of surface channel hydrogen-terminated transistors with FET gate lengths of 250 nm and 120 nm showing performance comparable to other devices published to date. The gate length was then scaled for the first time to sub-100 nm dimensions with a 50 nm gate length FET fabricated giving record high-frequency performance with a fT of 53 GHz. An adapted fabrication procedure was developed for this project with special attention paid to the volatility of the particles upon the diamond surface. Equivalent RF circuit models were extracted for each gate length and analysed in detail. Work was then undertaken to investigate a more stable alternative to the atmospheric induced doping effect with alternative electron accepting materials being deposited upon the hydrogen-terminated diamond surface. The as yet untested organic material F16CuPc was deposited on to hydrogen-terminated diamond and demonstrated its ability to encapsulate and preserve the atmospheric induced sub-surface conductivity at room temperature. For the first time an inorganic material was also investigated as a potential encapsulation for the hydrogen-terminated diamond surface, MoO3 was chosen due to its high electron affinity and like F16CuPc also showed the ability to preserve and

  1. Review on the effects of hydrogen at extreme pressures and temperatures on the mechanical behavior of polymers.

    SciTech Connect

    Hecht, Ethan S.

    2013-03-01

    The effects of hydrogen on the mechanics (e.g. strength, ductility, and fatigue resistance) of polymer materials are outlined in this report. There are a small number of studies reported in the literature on this topic, and even fewer at the extreme temperatures to which hydrogen service materials will be exposed. Several studies found little evidence that hydrogen affects the static tensile properties, long term creep, or ductile fracture of high density polyethylene or polyamide. However, there has been a report that a recoverable drop in the modulus of high density polyethylene is observable under high hydrogen pressure. A research need exists on the mechanical effects of hydrogen on the wide range of polymers used or considered for use in the hydrogen economy, due to the lack of data in the literature.

  2. High Pressure Hydrogen Materials Compatibility of Piezoelectric Films

    SciTech Connect

    Alvine, Kyle J.; Shutthanandan, V.; Bennett, Wendy D.; Bonham, Charles C.; Skorski, Daniel C.; Pitman, Stan G.; Dahl, Michael E.; Henager, Charles H.

    2010-12-02

    Abstract: Hydrogen is being considered as a next-generation clean burning fuel. However, hydrogen has well known materials issues, including blistering and embrittlement in metals. Piezoelectric materials are used as actuators in hydrogen fuel technology. We present studies of materials compatibility of piezoelectric films in a high pressure hydrogen environment. Absorption of high pressure hydrogen was studied with Elastic Recoil Detection Analysis (ERDA) and Rutherford Back Scattering (RBS) in lead zirconate titanate (PZT) and barium titanate (BTO) thin films. Hydrogen surface degradation in the form of blistering and Pb mixing was also observed.

  3. Processing Raman Spectra of High-Pressure Hydrogen Flames

    NASA Technical Reports Server (NTRS)

    Nguyen, Quang-Viet; Kojima, Jun

    2006-01-01

    The Raman Code automates the analysis of laser-Raman-spectroscopy data for diagnosis of combustion at high pressure. On the basis of the theory of molecular spectroscopy, the software calculates the rovibrational and pure rotational Raman spectra of H2, O2, N2, and H2O in hydrogen/air flames at given temperatures and pressures. Given a set of Raman spectral data from measurements on a given flame and results from the aforementioned calculations, the software calculates the thermodynamic temperature and number densities of the aforementioned species. The software accounts for collisional spectral-line-broadening effects at pressures up to 60 bar (6 MPa). The line-broadening effects increase with pressure and thereby complicate the analysis. The software also corrects for spectral interference ("cross-talk") among the various chemical species. In the absence of such correction, the cross-talk is a significant source of error in temperatures and number densities. This is the first known comprehensive computer code that, when used in conjunction with a spectral calibration database, can process Raman-scattering spectral data from high-pressure hydrogen/air flames to obtain temperatures accurate to within 10 K and chemical-species number densities accurate to within 2 percent.

  4. High-Performance Palladium Based Membrane for Hydrogen Separation and Purification

    SciTech Connect

    Hopkins, Scott

    2012-01-31

    The mission of the DOE's Fuel Cell Technologies'Hydrogen Fuels R&D effort is to research, develop, and validate technologies for producing, storing, and delivering hydrogen in an efficient, clean, safe, reliable, and affordable manner. A key program technical milestone for hydrogen technology readiness is to produce hydrogen from diverse, domestic resources at $2.00-$3.00 per gallon of gasoline equivalent (gge) delivered, untaxed. Low-cost, high-temperature hydrogen separation membranes represent a key enabling technology for small-scale distributed hydrogen production units. Availability of such membranes with high selectivity and high permeability for hydrogen will allow their integration with hydrocarbon reforming and water gas shift reactions, potentially reducing the cost of hydrogen produced. Pd-metal-based dense membranes are known for their excellent hydrogen selectivity and permeability characteristics, however, utilization of these membranes has so far been limited to small scale niche markets for hydrogen purification primarily due to the relatively high cost of Pd-alloy tubes compared to pressure swing adsorption (PSA) units. This project was aimed at development of thin-film Pd-alloy membranes deposited on Pall Corporation's DOE-based AccuSep® porous metal tube substrates to form a composite hydrogen separation membrane for these applications. Pall's composite membrane development addressed the typical limitations of composite structures by developing robust membranes capable of withstanding thermal and mechanical stresses resulting from high temperature (400C), high pressure (400 psi steam methane reformer and 1000 psi coal) operations and thermal cycling involved in conventional hydrogen production. In addition, the Pd-alloy membrane composition was optimized to be able to offer the most stability in the typical synthesis gas environments produced by reforming of natural gas and bio-derived liquid fuels (BILI) validating the technical

  5. High Temperature Solar Cell Development

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Raffaelle, Ryne P.; Merritt, Danielle

    2004-01-01

    The majority of satellites and near-earth probes developed to date have used photovoltaic arrays for power generation. If future mission to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. In this paper, we derive the optimum bandgap as a function of the operating temperature.

  6. Advanced High Temperature Structural Seals

    NASA Technical Reports Server (NTRS)

    Newquist, Charles W.; Verzemnieks, Juris; Keller, Peter C.; Rorabaugh, Michael; Shorey, Mark

    2002-01-01

    This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 pound payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs.

  7. Molecular Dynamics Simulations of Temperature Equilibration in Dense Hydrogen

    SciTech Connect

    Glosli, J; Graziani, F; More, R; Murillo, M; Streitz, F; Surh, M; Benedict, L; Hau-Riege, S; Langdon, A; London, R

    2008-02-14

    The temperature equilibration rate in dense hydrogen (for both T{sub i} > T{sub e} and T{sub i} < T{sub e}) has been calculated with large-scale molecular dynamics simulations for temperatures between 10 and 300 eV and densities between 10{sup 20}/cc to 10{sup 24}/cc. Careful attention has been devoted to convergence of the simulations, including the role of semiclassical potentials. We find that for Coulomb logarithms L {approx}> 1, Brown-Preston-Singleton [Brown et al., Phys. Rep. 410, 237 (2005)] with the sub-leading corrections and the fit of Gericke-Murillo-Schlanges [Gericke et al., PRE 65, 036418 (2003)] to the T-matrix evaluation of the collision operator, agrees with the MD data to within the error bars of the simulation. For more strongly-coupled plasmas where L {approx}< 1, our numerical results are consistent with the fit of Gericke-Murillo-Schlanges.

  8. Hydrogen Permeability of Polymer Matrix Composites at Cryogenic Temperatures

    NASA Technical Reports Server (NTRS)

    Grenoble, Ray W.; Gates, Thomas S

    2005-01-01

    This paper presents experimental methods and results of an ongoing study of the correlation between damage state and hydrogen gas permeability of laminated composite materials under mechanical strains and thermal loads. A specimen made from IM-7/977-2 composite material has been mechanically cycled at room temperature to induce microcrack damage. Crack density and tensile modulus were observed as functions of number of cycles. Damage development was found to occur most quickly in the off-axis plies near the outside of the laminate. Permeability measurements were made after 170,000 cycles and 430,000 cycles. Leak rate was found to depend on applied mechanical strain, crack density, and test temperature.

  9. Development of high strength, high temperature ceramics

    NASA Technical Reports Server (NTRS)

    Hall, W. B.

    1982-01-01

    Improvement in the high-pressure turbopumps, both fuel and oxidizer, in the Space Shuttle main engine were considered. The operation of these pumps is limited by temperature restrictions of the metallic components used in these pumps. Ceramic materials that retain strength at high temperatures and appear to be promising candidates for use as turbine blades and impellers are discussed. These high strength materials are sensitive to many related processing parameters such as impurities, sintering aids, reaction aids, particle size, processing temperature, and post thermal treatment. The specific objectives of the study were to: (1) identify and define the processing parameters that affect the properties of Si3N4 ceramic materials, (2) design and assembly equipment required for processing high strength ceramics, (3) design and assemble test apparatus for evaluating the high temperature properties of Si3N4, and (4) conduct a research program of manufacturing and evaluating Si3N4 materials as applicable to rocket engine applications.

  10. On the temperature dependence of H-U{sub iso} in the riding hydrogen model

    SciTech Connect

    Lübben, Jens; Volkmann, Christian; Grabowsky, Simon; Edwards, Alison; Morgenroth, Wolfgang; Fabbiani, Francesca P. A.; Sheldrick, George M.; Dittrich, Birger

    2014-07-01

    The temperature dependence of hydrogen U{sub iso} and parent U{sub eq} in the riding hydrogen model is investigated by neutron diffraction, aspherical-atom refinements and QM/MM and MO/MO cluster calculations. Fixed values of 1.2 or 1.5 appear to be underestimated, especially at temperatures below 100 K. The temperature dependence of H-U{sub iso} in N-acetyl-l-4-hydroxyproline monohydrate is investigated. Imposing a constant temperature-independent multiplier of 1.2 or 1.5 for the riding hydrogen model is found to be inaccurate, and severely underestimates H-U{sub iso} below 100 K. Neutron diffraction data at temperatures of 9, 150, 200 and 250 K provide benchmark results for this study. X-ray diffraction data to high resolution, collected at temperatures of 9, 30, 50, 75, 100, 150, 200 and 250 K (synchrotron and home source), reproduce neutron results only when evaluated by aspherical-atom refinement models, since these take into account bonding and lone-pair electron density; both invariom and Hirshfeld-atom refinement models enable a more precise determination of the magnitude of H-atom displacements than independent-atom model refinements. Experimental efforts are complemented by computing displacement parameters following the TLS+ONIOM approach. A satisfactory agreement between all approaches is found.

  11. Metal-diboride nanotubes as high capacity hydrogen storage media

    SciTech Connect

    Meng, Sheng; Kaxiras, Efthimios; Zhang, Zhenyu

    2007-01-01

    We investigate the potential for hydrogen storage of a new class of nanomaterials, metal-diboride nanotubes. These materials have the merits of high density of binding sites on the tubular surfaces without the adverse effects of metal clustering. Using the TiB2 (8,0) and (5,5) nanotube as prototype examples, we show through first-principles calculations that each Ti atom can host two intact H2 units, leading to a retrievable hydrogen storage capacity of 5.5 wt%. Most strikingly, the binding energies fall in the desirable range of 0.2-0.6 eV per H2 molecule, endowing these structures with the potential for room temperature, near ambient pressure applications.

  12. Effects of high pressure hydrogen on metals

    NASA Technical Reports Server (NTRS)

    Chandler, W. T.; Walter, R. J.

    1970-01-01

    Hydrogen environment embrittlement causes failure of hydrogen storage vessels at and below design pressures of 5000 to 6000 psi. Investigation of thirty-five alloys determines their susceptibility to such embrittlement.

  13. Electrochemical study of hydrogen permeation through tungsten near room temperature

    NASA Astrophysics Data System (ADS)

    Manhard, A.; Kapser, S.; Gao, L.

    2015-08-01

    We used an electrochemical double cell to study permeation of hydrogen through a 3.5 μm thick sputter-deposited tungsten layer on a 25 μm thick palladium support. The temperature dependence of the steady-state permeation current was studied in the range from 266 to 333 K for a constant charging potential on the entry side and zero hydrogen concentration on the exit side of the sample foil. We found that the data is best described by a sum of two Arrhenius terms. We postulate that the higher activation energy of 0.86 ± 0.07 eV corresponds to permeation through bulk grains and may approach the literature value of 1.43 ± 0.26 eV for even higher temperature. For the second, lower activation energy of 0.39 ± 0.03 eV, we currently consider fast diffusion along grain boundaries the most likely explanation.

  14. High temperature turbine engine structure

    DOEpatents

    Boyd, Gary L.

    1990-01-01

    A high temperature turbine engine includes a hybrid ceramic/metallic rotor member having ceramic/metal joint structure. The disclosed joint is able to endure higher temperatures than previously possible, and aids in controlling heat transfer in the rotor member.

  15. A study pertaining to a very low temperature hydrogen maser feasibility

    NASA Technical Reports Server (NTRS)

    Crampton, S. B.

    1982-01-01

    Very low temperature atomic hydrogen masers were developed. The advantages over room temperature hydrogen masers include higher radiated power due to the higher beam intensities possible using low temperature techniques and the much smaller electron spin flip cross section at low temperatures, lower cavity and amplifier noise temperatures, increased stability against mechanical creep at low temperatures, and opportunities to extend H atom collision studies to low temperatures, where quantum effects and details of the interatomic potentials are much more important.

  16. Synchrotron radiation photoemission study of metal overlayers on hydrogenated amorphous silicon at room temperature

    SciTech Connect

    Pi, J.

    1990-09-21

    In this dissertation, metals deposited on a hydrogenated amorphous silicon (a-Si:H) film at room temperature are studied. The purpose of this work is mainly understanding the electronic properties of the interface, using high-resolution synchrotron radiation photoemission techniques as a probe. Atomic hydrogen plays an important role in passivating dangling bonds of a-Si:H films, thus reducing the gap-state distribution. In addition, singly bonded hydrogen also reduces states at the top of the valence band which are now replaced by deeper Si-H bonding states. The interface is formed by evaporating metal on an a-Si:H film in successive accumulations at room temperature. Au, Ag, and Cr were chosen as the deposited metals. Undoped films were used as substrates. Since some unique features can be found in a-Si:H, such as surface enrichment of hydrogen diffused from the bulk and instability of the free surface, we do not expect the metals/a-Si:H interface to behave exactly as its crystalline counterpart. Metal deposits, at low coverages, are found to gather preferentially around regions deficient in hydrogen. As the thickness is increased, some Si atoms in those regions are likely to leave their sites to intermix with metal overlayers like Au and Cr. 129 refs., 30 figs.

  17. Magnetic suspension using high temperature superconducting cores

    NASA Technical Reports Server (NTRS)

    Scurlock, R. G.

    1992-01-01

    The development of YBCO high temperature superconductors, in wire and tape forms, is rapidly approaching the point where the bulk transport current density j vs magnetic field H characteristics with liquid nitrogen cooling will enable its use in model cores. On the other hand, BSCCO high temperature superconductor in wire form has poor j-H characteristics at 77 K today, although with liquid helium or hydrogen cooling, it appears to be superior to NbTi superconductor. Since liquid nitrogen cooling is approx. 100 times cheaper than liquid helium cooling, the use of YBCO is very attractive for use in magnetic suspension. The design is discussed of a model core to accommodate lift and drag loads up to 6000 and 3000 N respectively. A comparison is made between the design performance of a liquid helium cooled NbTi (or BSCCO) superconducting core and a liquid nitrogen cooled YBCO superconducting core.

  18. High temperature structural insulating material

    DOEpatents

    Chen, W.Y.

    1984-07-27

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800/sup 0/C), low thermal conductivity (below about 0.2 W/m/sup 0/C), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800/sup 0/C, a diameter within the range of 20-200 ..mu..m, and a wall thickness in the range of about 2 to 4 ..mu..m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  19. High temperature structural insulating material

    DOEpatents

    Chen, Wayne Y.

    1987-01-06

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800.degree. C.), low thermal conductivity (below about 0.2 W/m.degree. C.), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800.degree. C., a diameter within the range of 20-200 .mu.m, and a wall thickness in the range of about 2-4 .mu.m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  20. High temperature structural insulating material

    DOEpatents

    Chen, Wayne Y.

    1987-01-01

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800.degree. C.), low thermal conductivity (below about 0.2 W/m.degree. C.), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800.degree. C., a diameter within the range of 20-200 .mu.m, and a wall thickness in the range of about 2-4 .mu.m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  1. Advanced High Temperature Structural Seals

    NASA Technical Reports Server (NTRS)

    Newquist, Charles W.; Verzemnieks, Juris; Keller, Peter C.; Shorey, Mark W.; Steinetz, Bruce (Technical Monitor)

    2000-01-01

    This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 lb payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs. During the first phase of this program the existing launch vehicle control surface sealing concepts were reviewed, the aerothermal environment for a high temperature seal design was analyzed and a mock up of an arc-jet test fixture for evaluating seal concepts was fabricated.

  2. Containerless high temperature calorimeter apparatus

    NASA Technical Reports Server (NTRS)

    Lacy, L. L.; Nisen, D. B. (Inventor)

    1981-01-01

    A calorimeter apparatus for measuring high temperature thermophysical properties of materials is disclosed which includes a containerless heating apparatus in which the specimen is suspended and heated by electron bombardment.

  3. High temperature current mirror amplifier

    DOEpatents

    Patterson, III, Raymond B.

    1984-05-22

    A high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased. For accuracy, a second current mirror is provided with a biasing means and current means on the input leg.

  4. Low Cost, High Efficiency, High Pressure Hydrogen Storage

    SciTech Connect

    Mark Leavitt

    2010-03-31

    A technical and design evaluation was carried out to meet DOE hydrogen fuel targets for 2010. These targets consisted of a system gravimetric capacity of 2.0 kWh/kg, a system volumetric capacity of 1.5 kWh/L and a system cost of $4/kWh. In compressed hydrogen storage systems, the vast majority of the weight and volume is associated with the hydrogen storage tank. In order to meet gravimetric targets for compressed hydrogen tanks, 10,000 psi carbon resin composites were used to provide the high strength required as well as low weight. For the 10,000 psi tanks, carbon fiber is the largest portion of their cost. Quantum Technologies is a tier one hydrogen system supplier for automotive companies around the world. Over the course of the program Quantum focused on development of technology to allow the compressed hydrogen storage tank to meet DOE goals. At the start of the program in 2004 Quantum was supplying systems with a specific energy of 1.1-1.6 kWh/kg, a volumetric capacity of 1.3 kWh/L and a cost of $73/kWh. Based on the inequities between DOE targets and Quantum’s then current capabilities, focus was placed first on cost reduction and second on weight reduction. Both of these were to be accomplished without reduction of the fuel system’s performance or reliability. Three distinct areas were investigated; optimization of composite structures, development of “smart tanks” that could monitor health of tank thus allowing for lower design safety factor, and the development of “Cool Fuel” technology to allow higher density gas to be stored, thus allowing smaller/lower pressure tanks that would hold the required fuel supply. The second phase of the project deals with three additional distinct tasks focusing on composite structure optimization, liner optimization, and metal.

  5. LOX vaporization in high-pressure, hydrogen-rich gas

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.; Jeng, San-Mou

    1990-01-01

    LOX droplet vaporization in high-pressure hydrogen-rich gas is analyzed, with special attention to thermodynamic effects which compel the surface to heat to the critical state and to supercritical vaporization processes on heating to criticality. Subcritical vaporization is modeled using a quasi-steady diffusion-controlled gas-phase transport formulation coupled to an effective-conductivity internal-energy-transport model accounting for circulation effects. It is demonstrated how the droplet surface might heat to the critical state, for ambient pressures slightly greater than the critical pressure of oxygen, such that the bulk of propellant within the droplet remains substantially below the critical mixing temperature.

  6. Low-temperature ignition delay for hydrogen-air mixtures in light of a reaction mechanism with quantum correction

    NASA Astrophysics Data System (ADS)

    Medvedev, S. P.; Agafonov, G. L.; Khomik, S. V.

    2016-09-01

    A reaction mechanism with quantum correction is used to model low-temperature/high-pressure autoignition of lean hydrogen-air mixtures. This approach provides a good approximation for experimental data on autoignition delay and the low activation energy observed in experiments. Calculated results demonstrate that ignition delay time is inversely proportional to pressure, squared. The proposed scaling reduces spread in experimental data. The application of a quantum correction to hydrogen oxidation provides a basis for developing a general reaction mechanism that can be used to predict the autoignition behavior of hydrogen over an entire temperature/pressure range relevant to rocket engine conditions.

  7. HYFIRE: fusion-high temperature electrolysis system

    SciTech Connect

    Fillo, J A; Powell, J R; Steinberg, M; Benenati, R; Dang, V D; Horn, F; Isaacs, H; Lazareth, O; Makowitz, H; Usher, J

    1980-01-01

    The Brookhaven National Laboratory (BNL) is carrying out a comprehensive conceptual design study called HYFIRE of a commercial fusion Tokamak reactor, high-temperature electrolysis system. The study is placing particular emphasis on the adaptability of the STARFIRE power reactor to a synfuel application. The HYFIRE blanket must perform three functions: (a) provide high-temperature (approx. 1400/sup 0/C) process steam at moderate pressures (in the range of 10 to 30 atm) to the high-temperature electrolysis (HTE) units; (b) provide high-temperature (approx. 700 to 800/sup 0/C) heat to a thermal power cycle for generation of electricity to the HTE units; and (c) breed enough tritium to sustain the D-T fuel cycle. In addition to thermal energy for the decomposition of steam into its constitutents, H/sub 2/ and O/sub 2/, electrical input is required. Power cycle efficiencies of approx. 40% require He cooling for steam superheat. Fourteen hundred degree steam coupled with 40% power cycle efficiency results in a process efficiency (conversion of fusion energy to hydrogen chemical energy) of 50%.

  8. High-pressure hydrogen testing of single crystal superalloys for advanced rocket engine turbopump turbine blades

    NASA Technical Reports Server (NTRS)

    Alter, W. S.; Parr, R. A.; Johnston, M. H.; Strizak, J. P.

    1984-01-01

    A screening program to determine the effects of high pressure hydrogen on selected candidate materials for advanced single crystal turbine blade applications is examined. The alloys chosen for the investigation are CM SX-2, CM SX-4C, Rene N-4, and PWA1480. Testing is carried out in hydrogen and helium at 34 MPa and room temperature, with both notched and unnotched single crystal specimens. Results show a significant variation in susceptibility to Hydrogen Environment Embrittlement (HEE) among the four alloys and a marked difference in fracture topography between hydrogen and helium environment specimens.

  9. High temperature lightweight foamed cements

    DOEpatents

    Sugama, Toshifumi.

    1989-10-03

    Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures. The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed. 3 figs.

  10. High temperature lightweight foamed cements

    DOEpatents

    Sugama, Toshifumi

    1989-01-01

    Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures. The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed.

  11. Temperature controlled high voltage regulator

    DOEpatents

    Chiaro, Jr., Peter J.; Schulze, Gerald K.

    2004-04-20

    A temperature controlled high voltage regulator for automatically adjusting the high voltage applied to a radiation detector is described. The regulator is a solid state device that is independent of the attached radiation detector, enabling the regulator to be used by various models of radiation detectors, such as gas flow proportional radiation detectors.

  12. High temperature electronic gain device

    DOEpatents

    McCormick, J. Byron; Depp, Steven W.; Hamilton, Douglas J.; Kerwin, William J.

    1979-01-01

    An integrated thermionic device suitable for use in high temperature, high radiation environments. Cathode and control electrodes are deposited on a first substrate facing an anode on a second substrate. The substrates are sealed to a refractory wall and evacuated to form an integrated triode vacuum tube.

  13. High temperature Seebeck coefficient metrology

    SciTech Connect

    Martin, J.; Tritt, T.; Uher, C.

    2010-12-15

    We present an overview of the challenges and practices of thermoelectric metrology on bulk materials at high temperature (300 to 1300 K). The Seebeck coefficient, when combined with thermal and electrical conductivity, is an essential property measurement for evaluating the potential performance of novel thermoelectric materials. However, there is some question as to which measurement technique(s) provides the most accurate determination of the Seebeck coefficient at high temperature. This has led to the implementation of nonideal practices that have further complicated the confirmation of reported high ZT materials. To ensure meaningful interlaboratory comparison of data, thermoelectric measurements must be reliable, accurate, and consistent. This article will summarize and compare the relevant measurement techniques and apparatus designs required to effectively manage uncertainty, while also providing a reference resource of previous advances in high temperature thermoelectric metrology.

  14. Gallium phosphide high temperature diodes

    SciTech Connect

    Chaffin, R.J.; Dawson, L.R.

    1981-01-01

    The purpose of this work is to develop high temperature (> 300/sup 0/C) diodes for geothermal and other energy applications. A comparison of reverse leakage currents of Si, GaAs and GaP is made. Diodes made from GaP should be usable to > 500/sup 0/C. An LPE process for producing high quality, grown junction GaP diodes is described. This process uses low vapor pressure Mg as a dopant which allows multiple boat growth in the same LPE run. These LPE wafers have been cut into die and metallized to make the diodes. These diodes produce leakage currents below 10/sup -3/ A/cm/sup 2/ at 400/sup 0/C while exhibiting good high temperature rectification characteristics. High temperature life test data is presented which shows exceptional stability of the V-I characteristics.

  15. Effects of wall coatings and temperature on hydrogen atom surface recombination

    NASA Technical Reports Server (NTRS)

    Wong, E. L.; Baker, C. E.

    1973-01-01

    The efficiency of various surface coatings and materials toward inhibiting hydrogen atom surface recombination was investigated over a temperature range of 77 to 298 K. A flow discharge, mass spectrometer technique was used to make the experimental measurements. Hydrogen atoms were monitored directly, and these measurements were expressed as ratios of mass spectrometer peak heights for atomic and molecular hydrogen. Several of the surface coatings studied were efficient at reducing hydrogen atom surface recombination at room temperature. However, as the temperature was lowered, this efficiency was drastically reduced. Calibration of the mass spectrometer for atomic and molecular hydrogen indicated that mass spectrometer discrimination against hydrogen atoms was severe. Mass spectrometer sensitivity for hydrogen atoms was only about one-sixth of that for molecular hydrogen.

  16. Surface morphology of orthorhombic Mo2C catalyst and high coverage hydrogen adsorption

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Tian, Xinxin; Yang, Yong; Li, Yong-Wang; Wang, Jianguo; Beller, Matthias; Jiao, Haijun

    2016-09-01

    High coverage hydrogen adsorption on twenty two terminations of orthorhombic Mo2C has been systematically studied by using density functional theory and ab initio thermodynamics. Hydrogen stable coverage on the surfaces highly depends on temperatures and H2 partial pressure. The estimated hydrogen desorption temperatures under ultra-high vacuum condition on Mo2C are in reasonable agreement with the available temperature-programmed desorption data. Obviously, hydrogen adsorption can affect the surface stability and therefore modify the surface morphology of Mo2C. Upon increasing the chemical potential of hydrogen which can be achieved by increasing the H2 partial pressure and/or decreasing the temperature, the proportions of the (001), (010), (011) and (100) surfaces increase, while those of the (101), (110) and (111) surfaces decrease. Among these surfaces, the (100) surface is most sensitive upon hydrogen adsorption and the (111) surface is most exposed under a wide range of conditions. Our study clearly reveals the role of hydrogen on the morphology of orthorhombic Mo2C catalyst in conjugation with hydro-treating activity.

  17. Temperature optimization of high con

    NASA Astrophysics Data System (ADS)

    Sabry, M.

    2016-06-01

    Active cooling is essential for solar cells operating under high optical concentration ratios. A system comprises four solar cells that are in thermal contact on top of a copper tube is proposed. Water is flowing inside the tube in order to reduce solar cells temperature for increasing their performance. Computational Fluid Dynamics (CFD) simulation of such system has been performed in order to investigate the effect of water flow rate, tube internal diameter, and convective heat transfer coefficient on the temperature of the solar cells. It is found that increasing convective heat transfer coefficient has a significant effect on reducing solar cells temperatures operating at low flow rates and high optical concentration ratios. Also, a further increase of water flow rate has no effect on reducing cells temperatures.

  18. Containerless high-temperature calorimeter

    NASA Technical Reports Server (NTRS)

    Lacy, L. L.; Nisen, D. B.; Robinson, M. B.

    1979-01-01

    Samples are heated by electron bombardment in high-temperature calorimeter that operates from 1,000 to 3,600 C yet consumes less that 100 watts at temperatures less than 2,500 C. Contamination of samples is kept to minimum by suspending them from wire in vacuum chamber. Various sample slopes such as wires, dishs, spheres, rods, or irregular bodies can be accommodated and only about 100 nq of samples are needed for accurate measurements.

  19. HIgh Temperature Photocatalysis over Semiconductors

    NASA Astrophysics Data System (ADS)

    Westrich, Thomas A.

    Due in large part to in prevalence of solar energy, increasing demand of energy production (from all sources), and the uncertain future of petroleum energy feedstocks, solar energy harvesting and other photochemical systems will play a major role in the developing energy market. This dissertation focuses on a novel photochemical reaction process: high temperature photocatalysis (i.e., photocatalysis conducted above ambient temperatures, T ≥ 100°C). The overarching hypothesis of this process is that photo-generated charge carriers are able to constructively participate in thermo-catalytic chemical reactions, thereby increasing catalytic rates at one temperature, or maintaining catalytic rates at lower temperatures. The photocatalytic oxidation of carbon deposits in an operational hydrocarbon reformer is one envisioned application of high temperature photocatalysis. Carbon build-up during hydrocarbon reforming results in catalyst deactivation, in the worst cases, this was shown to happen in a period of minutes with a liquid hydrocarbon. In the presence of steam, oxygen, and above-ambient temperatures, carbonaceous deposits were photocatalytically oxidized over very long periods (t ≥ 24 hours). This initial experiment exemplified the necessity of a fundamental assessment of high temperature photocatalytic activity. Fundamental understanding of the mechanisms that affect photocatalytic activity as a function of temperatures was achieved using an ethylene photocatalytic oxidation probe reaction. Maximum ethylene photocatalytic oxidation rates were observed between 100 °C and 200 °C; the maximum photocatalytic rates were approximately a factor of 2 larger than photocatalytic rates at ambient temperatures. The loss of photocatalytic activity at temperatures above 200 °C is due to a non-radiative multi-phonon recombination mechanism. Further, it was shown that the fundamental rate of recombination (as a function of temperature) can be effectively modeled as a

  20. Method for low temperature catalytic production of hydrogen

    DOEpatents

    Mahajan, Devinder

    2003-07-22

    The invention provides a process for the catalytic production of a hydrogen feed by exposing a hydrogen feed to a catalyst which promotes a base-catalyzed water-gas-shift reaction in a liquid phase. The hydrogen feed can be provided by any process known in the art of making hydrogen gas. It is preferably provided by a process that can produce a hydrogen feed for use in proton exchange membrane fuel cells. The step of exposing the hydrogen feed takes place preferably from about 80.degree. C. to about 150.degree. C.

  1. Rotational and vibrational temperatures in a hydrogen discharge with a magnetic X-point

    SciTech Connect

    Tsankov, Tsanko V.; Czarnetzki, Uwe; Toko, Kaoru

    2012-12-15

    A novel plasma source with a magnetic X-point has been developed to probe an alternative for cesium-free negative hydrogen ion production. This study presents first results for the gas and vibrational temperatures in the source at 1 Pa and various RF powers. The temperatures are obtained from analysis of the intensity distribution of the molecular Fulcher-{alpha} bands. The gas temperature increases with the RF power, while the vibrational temperature remains constant in the studied range of RF powers. Both quantities show no appreciable spatial dependence. The obtained high values of the vibrational temperatures indicate a high population of the vibrational levels, favourable for the volume negative ion production. A theoretical concept indicates the presence of an optimum value for the vibrational temperature at which the negative hydrogen ion yield by volume processes has a maximum. Coincidently, the measured value is close to this optimum. This indicates that the novel concept can provide certain advantages compared to other sources based on volume production.

  2. Mechanism of the formation of hydrogen tetroxide and peroxide via low-temperature interaction between hydrogen atoms and molecular oxygen

    NASA Astrophysics Data System (ADS)

    Levanov, A. V.; Isaikina, O. Ya.; Antipenko, E. E.; Lunin, V. V.

    2014-09-01

    A mechanism and kinetic model for the synthesis of peroxide radical condensate via the low-temperature interaction of hydrogen atoms with O2 molecules is proposed. The main components of the reaction, hydrogen tetroxide H2O4 and hydrogen peroxide H2O2, are formed in a low-temperature liquid layer formed near the cold surface during synthesis. Molecules of H2O4 and H2O2 are stabilized by transitioning to the solid phase. The dependences of the ratio on the ratio of concentrations of H and O2 in the gas phase, calculated on the basis of the model, are consistent with the experimental data.

  3. High Temperature Transparent Furnace Development

    NASA Technical Reports Server (NTRS)

    Bates, Stephen C.

    1997-01-01

    This report describes the use of novel techniques for heat containment that could be used to build a high temperature transparent furnace. The primary objective of the work was to experimentally demonstrate transparent furnace operation at 1200 C. Secondary objectives were to understand furnace operation and furnace component specification to enable the design and construction of a low power prototype furnace for delivery to NASA in a follow-up project. The basic approach of the research was to couple high temperature component design with simple concept demonstration experiments that modify a commercially available transparent furnace rated at lower temperature. A detailed energy balance of the operating transparent furnace was performed, calculating heat losses through the furnace components as a result of conduction, radiation, and convection. The transparent furnace shells and furnace components were redesigned to permit furnace operation at at least 1200 C. Techniques were developed that are expected to lead to significantly improved heat containment compared with current transparent furnaces. The design of a thermal profile in a multizone high temperature transparent furnace design was also addressed. Experiments were performed to verify the energy balance analysis, to demonstrate some of the major furnace improvement techniques developed, and to demonstrate the overall feasibility of a high temperature transparent furnace. The important objective of the research was achieved: to demonstrate the feasibility of operating a transparent furnace at 1200 C.

  4. High-Temperature Optical Sensor

    NASA Technical Reports Server (NTRS)

    Adamovsky, Grigory; Juergens, Jeffrey R.; Varga, Donald J.; Floyd, Bertram M.

    2010-01-01

    A high-temperature optical sensor (see Figure 1) has been developed that can operate at temperatures up to 1,000 C. The sensor development process consists of two parts: packaging of a fiber Bragg grating into a housing that allows a more sturdy thermally stable device, and a technological process to which the device is subjected to in order to meet environmental requirements of several hundred C. This technology uses a newly discovered phenomenon of the formation of thermally stable secondary Bragg gratings in communication-grade fibers at high temperatures to construct robust, optical, high-temperature sensors. Testing and performance evaluation (see Figure 2) of packaged sensors demonstrated operability of the devices at 1,000 C for several hundred hours, and during numerous thermal cycling from 400 to 800 C with different heating rates. The technology significantly extends applicability of optical sensors to high-temperature environments including ground testing of engines, flight propulsion control, thermal protection monitoring of launch vehicles, etc. It may also find applications in such non-aerospace arenas as monitoring of nuclear reactors, furnaces, chemical processes, and other hightemperature environments where other measurement techniques are either unreliable, dangerous, undesirable, or unavailable.

  5. Analysis of hydrogen vehicles with cryogenic high pressure storage

    SciTech Connect

    Aceves, S. M.; Berry, G. D.

    1998-06-19

    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LIQ) or ambient-temperature compressed hydrogen (CH2). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (lower energy requirement for hydrogen liquefaction and reduced evaporative losses). This paper shows an evaluation of the applicability of the insulated pressure vessels for light-duty vehicles. The paper shows an evaluation of evaporative losses and insulation requirements and a description of the current experimental plans for testing insulated pressure vessels. The results show significant advantages to the use of insulated pressure vessels for light-duty vehicles.

  6. Effect of Hydrogen and Carbon on the Melting Temperature of the Core

    NASA Astrophysics Data System (ADS)

    Nakajima, Y.; Sakamaki, K.; Takahashi, E.; Fukai, Y.; Suzuki, T.; Funakoshi, K.

    2007-12-01

    The temperature of the Earth's outer core has been discussed based on the melting temperature of Fe- O-S alloys (e.g., Boehler, 1996). Although hydrogen and carbon are the possible candidates of the core component, their effects on the melting temperature of iron at high-pressures are unclear. Using a Kawai-type multi-anvil apparatus at SPring-8 synchrotron, we carried out a series of melting experiments on FeH and Fe3C up to 20 and 28 GPa, respectively. In the experiments on FeH, Fe sponge mixed with MgO was packed into a NaCl container with a hydrogen source, LiAlH4 (e.g., Fukai et al., 1989). During heating under high-pressures, hydrogenation of iron was observed by volume change. The phase boundary between ɛ'-phase (low-temperature phase) and γ-phase (high-temperature phase) of iron-hydride was determined using both cooling and heating experiments. Hydrogen concentrations in the γ-FeHx and ɛ'-FeHx were calculated based on the excess volume data from that of pure iron. It is found that γ-FeHx and ɛ'-FeHx synthesized in our experiments at pressures between 10 and 20 GPa are nearly stoichiometric FeH. Melting temperature of the γ-FeH was determined by the abrupt change in the X-ray diffraction patterns (crystalline to amorphous). The melting temperatures were determined to be 1473, 1473, 1493, 1573 and 1593 K at 10, 11.5, 15, 18 and 20 GPa, respectively. In the experiments using Fe3C, the synthesized Fe3C powder was encapsulated in a MgO container. In the diffraction sequences during heating, the peaks of Fe3C disappeared, and the new peaks identified as those of Fe7C3 were observed with halo caused by liquid. Finally, the Fe7C3 peaks disappeared, and only the halo pattern was observed. Based on these observations, the incongruent melting of Fe3C to Fe7C3 and liquid is estimated to occur at 1823 and 1923 K at 19.7 and 27.0 GPa, respectively. The liquidus temperatures of the Fe3C composition are found to be at 2098 and 2198 K at 19.5 and 26.8 GPa

  7. High temperature current mirror amplifier

    DOEpatents

    Patterson, R.B. III.

    1984-05-22

    Disclosed is a high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased. For accuracy, a second current mirror is provided with a biasing means and current means on the input leg. 2 figs.

  8. High temperature superconductor current leads

    DOEpatents

    Hull, J.R.; Poeppel, R.B.

    1995-06-20

    An electrical lead is disclosed having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths. 9 figs.

  9. High temperature superconductor current leads

    DOEpatents

    Hull, John R.; Poeppel, Roger B.

    1995-01-01

    An electrical lead having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths.

  10. High Temperature Polymer Matrix Composites

    NASA Technical Reports Server (NTRS)

    1985-01-01

    These are the proceedings of the High Temperature Polymer Matrix Composites Conference held at the NASA Lewis Research Center on March 16 to 18, 1983. The purpose of the conference is to provide scientists and engineers working in the field of high temperature polymer matrix composites an opportunity to review, exchange, and assess the latest developments in this rapidly expanding area of materials technology. Technical papers are presented in the following areas: (1) matrix development; (2) adhesive development; (3) characterization; (4) environmental effects; and (5) applications.

  11. High temperature solar thermal technology

    NASA Technical Reports Server (NTRS)

    Leibowitz, L. P.; Hanseth, E. J.; Peelgren, M. L.

    1980-01-01

    Some advanced technology concepts under development for high-temperature solar thermal energy systems to achieve significant energy cost reductions and performance gains and thus promote the application of solar thermal power technology are presented. Consideration is given to the objectives, current efforts and recent test and analysis results in the development of high-temperature (950-1650 C) ceramic receivers, thermal storage module checker stoves, and the use of reversible chemical reactions to transport collected solar energy. It is pointed out that the analysis and testing of such components will accelerate the commercial deployment of solar energy.

  12. "Green" High-Temperature Polymers

    NASA Technical Reports Server (NTRS)

    Meador, Michael A.

    1998-01-01

    PMR-15 is a processable, high-temperature polymer developed at the NASA Lewis Research Center in the 1970's principally for aeropropulsion applications. Use of fiber-reinforced polymer matrix composites in these applications can lead to substantial weight savings, thereby leading to improved fuel economy, increased passenger and payload capacity, and better maneuverability. PMR-15 is used fairly extensively in military and commercial aircraft engines components seeing service temperatures as high as 500 F (260 C), such as the outer bypass duct for the F-404 engine. The current world-wide market for PMR-15 materials (resins, adhesives, and composites) is on the order of $6 to 10 million annually.

  13. Low temperature hydrogenation of iron nanoparticles on graphene

    PubMed Central

    Takahashi, Keisuke; Wang, Yongming; Chiba, Shotaro; Nakagawa, Yuki; Isobe, Shigehito; Ohnuki, Somei

    2014-01-01

    Hydrogenation of iron nanoparticles was performed both computationally and experimentally where previously chemically-bonded iron hydride is considered to be unachievable under ordinary conditions. Density functional theory (DFT) calculations predict that hydrogenated iron nanoparticles are stabilized on a single-layer graphene/Cu substrate. Experimentally, iron nanoparticles were deposited onto a graphene/Cu substrate by vacuum deposition. Hydrogenation was done at 1atm of hydrogen gas and under liquid nitrogen. Mass spectrometry peak confirmed the hydrogen release from hydrogenated iron nanoparticles while a scanning transmission electron microscopy is used in order to link a geometrical shape of iron hydride nanoparticles between experimental and theoretical treatments. The hydrogenated iron nanoparticles were successfully synthesized where hydrogenated iron nanoparticles are stable under ordinary conditions. PMID:24710406

  14. High specific energy, high capacity nickel-hydrogen cell design

    NASA Technical Reports Server (NTRS)

    Wheeler, James R.

    1993-01-01

    A 3.5 inch rabbit-ear-terminal nickel-hydrogen cell was designed and tested to deliver high capacity at steady discharge rates up to and including a C rate. Its specific energy yield of 60.6 wh/kg is believed to be the highest yet achieved in a slurry-process nickel-hydrogen cell, and its 10 C capacity of 113.9 AH the highest capacity yet of any type in a 3.5 inch diameter size. The cell also demonstrated a pulse capability of 180 amps for 20 seconds. Specific cell parameters and performance are described. Also covered is an episode of capacity fading due to electrode swelling and its successful recovery by means of additional activation procedures.

  15. Matrix effects on hydrogen-bonded complexes trapped in low-temperature matrices

    NASA Astrophysics Data System (ADS)

    Barnes, Austin J.; Mielke, Zofia

    2012-09-01

    There are several different possible matrix effects on hydrogen-bonded complexes trapped in low-temperature matrices: hydrogen-bonded complexes may be stabilised (compared with the gas phase) as a result of being trapped in a low-temperature matrix; metastable hydrogen-bonded complexes may be trapped in matrices; the matrix may influence the extent of proton transfer in a hydrogen-bonded complex; the matrix may influence the structure of a hydrogen-bonded complex. Each of these possible effects is examined in turn using selected examples from the literature as well as our own work.

  16. High-Temperature Electrostatic Levitator

    NASA Technical Reports Server (NTRS)

    Rhim, Won-Kyu; Chung, Sang K.

    1994-01-01

    High-temperature electrostatic levitator provides independent control of levitation and heating of sample in vacuum. Does not cause electromagnetic stirring in molten sample (such stirring causes early nucleation in undercooling). Maintenance of levitating force entails control of electrostatic field and electrical charge on sample.

  17. High-Temperature Vibration Damper

    NASA Technical Reports Server (NTRS)

    Clarke, Alan; Litwin, Joel; Krauss, Harold

    1987-01-01

    Device for damping vibrations functions at temperatures up to 400 degrees F. Dampens vibrational torque loads as high as 1,000 lb-in. but compact enough to be part of helicopter rotor hub. Rotary damper absorbs energy from vibrating rod, dissipating it in turbulent motion of viscous hydraulic fluid forced by moving vanes through small orifices.

  18. High-temperature plasma physics

    SciTech Connect

    Furth, H.P.

    1988-03-01

    Both magnetic and inertial confinement research are entering the plasma parameter range of fusion reactor interest. This paper reviews the individual and common technical problems of these two approaches to the generation of thermonuclear plasmas, and describes some related applications of high-temperature plasma physics.

  19. A solar high temperature kiln

    NASA Astrophysics Data System (ADS)

    Huettenhoelscher, N.; Bergmann, K.

    1981-11-01

    The feasibility of using solar energy in developing countries for baking ceramic construction materials was investigated. The solar high temperature kiln is described. It uses two parabolic concentrators which direct available radiation into the baking chamber. The Sun tracker has only one axis. Preliminary test results with the prototype kiln were satisfactory.

  20. High temperature turbine engine structure

    DOEpatents

    Boyd, Gary L.

    1991-01-01

    A high temperature turbine engine includes a rotor portion having axially stacked adjacent ceramic rotor parts. A ceramic/ceramic joint structure transmits torque between the rotor parts while maintaining coaxial alignment and axially spaced mutually parallel relation thereof despite thermal and centrifugal cycling.

  1. Enhanced diffusion of molecular hydrogen in germanosilicate fibres loaded with hydrogen at high pressures

    SciTech Connect

    Vasil'ev, Sergei A; Koltashev, V V; Sokolov, V O; Medvedkov, O I; Rybaltovsky, A A; Plotnichenko, V G; Dianov, Evgenii M; Rybaltovskii, A O; Klyamkin, Semen N; Malosiev, A R

    2005-03-31

    Absorption spectra and spontaneous Raman spectra of optical fibres with a germanosilicate core loaded with molecular hydrogen at a pressure of 150-170 MPa are studied; the variation of these spectra during the outdiffusion of hydrogen from the fibres is also investigated. The purely rotational transitions of molecular hydrogen in Raman spectra of optical fibres are recorded for the first time. The changes in the spectral parameters of fibre Bragg gratings loaded with hydrogen are analysed. It is observed for the first time that under such high loading pressures, the decrease in the hydrogen concentration in the fibre core after completion of hydrogen loading occurs in two clearly manifested stages, the initial stage being characterised by a more rapid outlet of hydrogen as compared to the dynamics of hydrogen outdiffusing at pressures of 10-15 MPa. Barodiffusion of molecular hydrogen in optical fibres is considered as the main mechanism explaining this effect. An increase in the solubility of molecular hydrogen in germanosilicate fibres exposed to UV radiation is observed for the first time. (optical fibres)

  2. Temperature-programmed elimination of tritium in coal labeled by tritiated gaseous hydrogen

    SciTech Connect

    Eika W. Qian; T. Horio; I. Putu Sutrisna

    2009-03-15

    The hydrogen exchange of an Argonne Pocahontas No. 3 (POC) coal with tritiated gaseous hydrogen in the presence of a Pt/Al{sub 2}O{sub 3} catalyst was carried out using a fixed-bed reactor at a temperature range of 200-250{sup o}C. Then, the tritiated coal sample was re-exchanged with hydrogen in a gaseous hydrogen atmosphere at different raising temperature rates. The changes in radioactivity of tritium releasing from the tritium-labeled coal sample in the temperature-programmed elimination (TPE) of tritium was monitored by a radioanalyzer in situ. The release profile of tritium was fit using three Gaussian distribution functions in TPE. On the basis of the waveform analysis, the amounts and activation energies of the hydrogen exchange for every type of exchangeable hydrogen were estimated. The values of exchange activation energies are 8.8 {+-} 0.5, 10.7 {+-} 0.5, and 16.3 {+-} 0.5 kcal/mol for three types of exchangeable hydrogen, respectively. The amount of type-I hydrogen was independent of the exchange reaction temperature. In contrast to this, the amount of types II and III of exchangeable hydrogen increased with an increasing exchange temperature, suggesting that the amount of types II and III of hydrogen in the coal is dependent upon the exchange temperature. 35 refs., 8 figs., 5 tabs.

  3. Hydrogen-plasma-induced Rapid, Low-Temperature Crystallization of μm-thick a-Si:H Films.

    PubMed

    Zhou, H P; Xu, M; Xu, S; Liu, L L; Liu, C X; Kwek, L C; Xu, L X

    2016-01-01

    Being a low-cost, mass-production-compatible route to attain crystalline silicon, post-deposition crystallization of amorphous silicon has received intensive research interest. Here we report a low-temperature (300 °C), rapid (crystallization rate of ~17 nm/min) means of a-Si:H crystallization based on high-density hydrogen plasma. A model integrating the three processes of hydrogen insertion, etching, and diffusion, which jointly determined the hydrogenation depth of the excess hydrogen into the treated micrometer thick a-Si:H, is proposed to elucidate the hydrogenation depth evolution and the crystallization mechanism. The effective temperature deduced from the hydrogen diffusion coefficient is far beyond the substrate temperature of 300 °C, which implies additional driving forces for crystallization, i.e., the chemical annealing/plasma heating and the high plasma sheath electric field. The features of LFICP (low-frequency inductively coupled plasma) and LFICP-grown a-Si:H are also briefly discussed to reveal the underlying mechanism of rapid crystallization at low temperatures. PMID:27600866

  4. Hydrogen-plasma-induced Rapid, Low-Temperature Crystallization of μm-thick a-Si:H Films

    PubMed Central

    Zhou, H. P.; Xu, M.; Xu, S.; Liu, L. L.; Liu, C. X.; Kwek, L. C.; Xu, L. X.

    2016-01-01

    Being a low-cost, mass-production-compatible route to attain crystalline silicon, post-deposition crystallization of amorphous silicon has received intensive research interest. Here we report a low-temperature (300 °C), rapid (crystallization rate of ~17 nm/min) means of a-Si:H crystallization based on high-density hydrogen plasma. A model integrating the three processes of hydrogen insertion, etching, and diffusion, which jointly determined the hydrogenation depth of the excess hydrogen into the treated micrometer thick a-Si:H, is proposed to elucidate the hydrogenation depth evolution and the crystallization mechanism. The effective temperature deduced from the hydrogen diffusion coefficient is far beyond the substrate temperature of 300 °C, which implies additional driving forces for crystallization, i.e., the chemical annealing/plasma heating and the high plasma sheath electric field. The features of LFICP (low-frequency inductively coupled plasma) and LFICP-grown a-Si:H are also briefly discussed to reveal the underlying mechanism of rapid crystallization at low temperatures. PMID:27600866

  5. High Temperature, High Power Piezoelectric Composite Transducers

    PubMed Central

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  6. High temperature, high power piezoelectric composite transducers.

    PubMed

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  7. Containerless high temperature property measurements

    NASA Technical Reports Server (NTRS)

    Nordine, Paul C.; Weber, J. K. Richard; Krishnan, Shankar; Anderson, Collin D.

    1991-01-01

    Containerless processing in the low gravity environment of space provides the opportunity to increase the temperature at which well controlled processing of and property measurements on materials is possible. This project was directed towards advancing containerless processing and property measurement techniques for application to materials research at high temperatures in space. Containerless high temperature material property studies include measurements of the vapor pressure, melting temperature, optical properties, and spectral emissivities of solid boron. The reaction of boron with nitrogen was also studied by laser polarimetric measurement of boron nitride film growth. The optical properties and spectral emissivities were measured for solid and liquid silicon, niobium, and zirconium; liquid aluminum and titanium; and liquid Ti-Al alloys of 5 to 60 atomic pct. titanium. Alternative means for noncontact temperature measurement in the absence of material emissivity data were evaluated. Also, the application of laser induced fluorescence for component activity measurements in electromagnetic levitated liquids was studied, along with the feasibility of a hybrid aerodynamic electromagnetic levitation technique.

  8. High-temperature containerless calorimeter

    NASA Technical Reports Server (NTRS)

    Robinson, M. B.; Lacy, L. L.

    1985-01-01

    A high-temperature (greater than 1500 K) containerless calorimeter is described and its usefulness demonstrated. The calorimeter uses the technique of omnidirectional electron bombardment of pendant drops to achieve an isothermal test environment. The small heat input into the sample (i.e., 15-50 W) can be controlled and measured. The apparatus can be used to determine the total hemispherical emissivity, specific heat, heat of fusion, surface tension, and equilibrium melting temperature of small molten drops in the temperature range of 1500 to 3500 K. The total hemispherical emissivity and specific heat of pure niobium and two alloys of niobium-germanium have been measured in the temperature range of 1700 to 2400 K. As reported in the literature, the total hemispherical emissivity varied as a function of temperature. However, specific heat values for both the pure metal and alloys seem to be independent of temperature. Specific heat for the liquid alloy phase was also measured and compared to the solid phase.

  9. Solute strengthening at high temperatures

    NASA Astrophysics Data System (ADS)

    Leyson, G. P. M.; Curtin, W. A.

    2016-08-01

    The high temperature behavior of solute strengthening has previously been treated approximately using various scaling arguments, resulting in logarithmic and power-law scalings for the stress-dependent energy barrier Δ E(τ ) versus stress τ. Here, a parameter-free solute strengthening model is extended to high temperatures/low stresses without any a priori assumptions on the functional form of Δ E(τ ) . The new model predicts that the well-established low-temperature, with energy barrier Δ {{E}\\text{b}} and zero temperature flow stress {τy0} , transitions to a near-logarithmic form for stresses in the regime 0.2<τ /{τy0}≤slant 0.5 and then transitions to a power-law form at even lower stresses τ /{τy0}<0.03 . Δ {{E}\\text{b}} and {τy0} remains as the reference energy and stress scales over the entire range of stresses. The model is applied to literature data on solution strengthening in Cu alloys and captures the experimental results quantitatively and qualitatively. Most importantly, the model accurately captures the transition in strength from the low-temperature to intermediate-temperature and the associated transition for the activation volume. Overall, the present analysis unifies the different qualitative models in the literature and, when coupled with the previous parameter-free solute strengthening model, provides a single predictive model for solute strengthening as a function of composition, temperature, and strain rate over the full range of practical utility.

  10. Utilization of high specific surface area CuO-CeO2 catalysts for high temperature processes of hydrogen production: steam re-forming of ethanol and methane dry re-forming.

    PubMed

    Djinović, Petar; Batista, Jurka; Cehić, Benis; Pintar, Albin

    2010-03-25

    CuO-CeO(2) mixed oxide catalysts with 10, 15, and 20 mol % CuO content were prepared by the hard template method using KIT-6 silica as a template. The applied synthesis method yields solids with BET surface area in excess of 147 m(2)/g, highly porous nanocrystalline CeO(2) morphology and dispersion of CuO phase between 28 and 40%, corresponding to CuO particle size between 1.3 and 1.9 nm. Increasing the CuO content caused a decrease in dispersion of this phase and a further decrease of surface acid site abundance, determined by NH(3) chemisorption/TPD method, but improved the reducibility extent of CeO(2) (14.5, 16.1 and 24.5% for CuCe10, CuCe15, and CuCe20 catalyst, respectively) and oxygen mobility of prepared powders. It was discovered during ethanol steam re-forming experiments that increasing CuO content is favorable in terms of ethanol conversion but also causes quicker catalyst deactivation, primarily as a result of sintering and loss of CuO dispersion. Reaction temperatures in excess of 550 degrees C strongly promoted ethanol dehydratation reaction, leading to a rise in methane production and extensive coking of the catalyst surface. Coking was slower in the case of CuO-CeO(2) catalysts with a higher CuO content as a result of lower acid site abundance and more pronounced oxygen mobility. Temperatures in excess of 450 degrees C are required for any noticeable CO(2) and CH(4) conversion in methane dry re-forming reaction over CuO-CeO(2) materials. The examined materials displayed steady performance during stability tests at a reaction temperature of 650 degrees C, with catalysts containing 15 and 20 mol % CuO exhibiting the highest activity. Additionally, very low amounts of carbon were deposited on spent catalyst samples. PMID:19883056

  11. High temperature sorbents for oxygen

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K. (Inventor)

    1994-01-01

    A sorbent capable of removing trace amounts of oxygen (ppt) from a gas stream at a high temperature above 200 C comprising a porous alumina silicate support, such as zeolite, containing from 1 to 10 percent by weight of ion exchanged transition metal, such as copper or cobalt ions, and 0.05 to 1.0 percent by weight of an activator selected from a platinum group metal such as platinum is described. The activation temperature, oxygen sorption, and reducibility are all improved by the presence of the platinum activator.

  12. High Temperature Sorbents for Oxygen

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K. (Inventor)

    1996-01-01

    A sorbent capable of removing trace amounts of oxygen (ppt) from a gas stream at a high temperature above 200 C is introduced. The sorbent comprises a porous alumina silicate support such as zeolite containing from 1 to 10 percent by weight of ion exchanged transition metal such as copper or cobalt ions and 0.05 to 1.0 percent by weight of an activator selected from a platinum group metal such as platinum. The activation temperature, oxygen sorption and reducibility are all improved by the presence of the platinum activator.

  13. High-Temperature Rocket Engine

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.; Rosenberg, Sanders D.; Chazen, Melvin L.

    1994-01-01

    Two rocket engines that operate at temperature of 2,500 K designed to provide thrust for station-keeping adjustments of geosynchronous satellites, for raising and lowering orbits, and for changing orbital planes. Also useful as final propulsion stages of launch vehicles delivering small satellites to low orbits around Earth. With further development, engines used on planetary exploration missions for orbital maneuvers. High-temperature technology of engines adaptable to gas-turbine combustors, ramjets, scramjets, and hot components of many energy-conversion systems.

  14. High Temperature Interactions of Antimony with Nickel

    SciTech Connect

    Marina, Olga A.; Pederson, Larry R.

    2012-07-01

    In this chapter, the surface and bulk interactions of antimony with the Ni-based anodes in solid oxide fuel cells (SOFC) will be discussed. High fuel flexibility is a significant advantage of SOFCs, allowing the direct use of fossil and bio fuels without a hydrogen separation unit. Synthesis gas derived from coal and biomass consists of a mixture of hydrogen, carbon monoxide, carbon dioxide, and steam, but finite amounts of tars and trace impurities such as S, Se, P, As, Sb, Cd, Pb, Cl, etc, are also always present. While synthesis gas is commonly treated with a series of chemical processes and scrubbers to remove the impurities, complete purification is not economical. Antimony is widely distributed in coals. During coal gasification antimony is volatilized, such that contact with the SOFC anodes and other SOFC parts, e.g., interconnect, current collecting wires, fuel gas supplying tubing, is most likely. This chapter addresses the following topics: high temperature Ni - Sb interactions; alteration phase, Ni3Sb, Ni5Sb2, NiSb, formation; thermochemical modeling; impact of Sb on the electrocatalytic activity of Ni toward the fuel oxidation and the presence of other impurities (sulfur, in particular); converted anode structural instability during long-term SOFC operation; comparison with nickel heterogeneous catalysts.

  15. Progress In High Temperature Electrolysis At The Idaho National Laboratory

    SciTech Connect

    Carl M. Stoots; James E.O'Brien; J. Steve Herring; Joseph Hartvigsen

    2007-10-01

    The United States is considering the development of a domestic hydrogen-based energy economy. Hydrogen is of particular interest as a secondary energy carrier because it has the potential to be storable, transportable, environmentally benign, and useful in many chemical processes. Obviously, before a hydrogen economy can be implemented, an efficient and environmentally friendly means for large scale hydrogen production must be identified, proven, and developed. Hydrogen is now produced primarily via steam reforming of methane. However, from a long-term perspective, methane reforming is not a viable process for large-scale production of hydrogen since such fossil fuel conversion processes consume non-renewable resources and emit greenhouse gases. The U. S. National Research Council has recommended the use of water-splitting technologies to produce hydrogen using energy derived from a nuclear reactor. For the past several years, the Idaho National Laboratory has been actively studying the use of solid oxide fuel cells in conjunction with nuclear power for large-scale, high-temperature, electrolytic hydrogen production.

  16. Non-syngas direct steam reforming of methanol to hydrogen and carbon dioxide at low temperature.

    PubMed

    Yu, Kai Man Kerry; Tong, Weiyi; West, Adam; Cheung, Kevin; Li, Tong; Smith, George; Guo, Yanglong; Tsang, Shik Chi Edman

    2012-01-01

    A non-syngas direct steam reforming route is investigated for the conversion of methanol to hydrogen and carbon dioxide over a CuZnGaO(x) catalyst at 150-200 °C. This route is in marked contrast with the conventional complex route involving steam reformation to syngas (CO/H2) at high temperature, followed by water gas shift and CO cleanup stages for hydrogen production. Here we report that high quality hydrogen and carbon dioxide can be produced in a single-step reaction over the catalyst, with no detectable CO (below detection limit of 1 ppm). This can be used to supply proton exchange membrane fuel cells for mobile applications without invoking any CO shift and cleanup stages. The working catalyst contains, on average, 3-4 nm copper particles, alongside extremely small size of copper clusters stabilized on a defective ZnGa2O4 spinel oxide surface, providing hydrogen productivity of 393.6 ml g(-1)-cat h(-1) at 150 °C. PMID:23187630

  17. High temperature drilling mud composition

    SciTech Connect

    Alexander, W.

    1988-10-18

    This patent describes a composition having improved rheological properties and improved stability at high temperatures and pressure for use in a water-based drilling mud comprising a high-yield bentonite, a low-yield bentonite and leonardite, wherein the weight ratio of the high-yield bentonite to the low-yield bentonites in the range of about 10:1 to about 1:1, and the leonardite is present in the amount of about 0.1% to 1.0% by total dry weight of the composition.

  18. High Temperature Transfer Molding Resins

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

    2000-01-01

    High temperature resins containing phenylethynyl groups that are processable by transfer molding have been prepared. These phenylethynyl containing oligomers were prepared from aromatic diamines containing phenylethynyl groups and various ratios of phthalic anhydride and 4-phenylethynlphthalic anhydride in glacial acetic acid to form a mixture of imide compounds in one step. This synthetic approach is advantageous since the products are a mixture of compounds and consequently exhibit a relatively low melting temperature. In addition, these materials exhibit low melt viscosities which are stable for several hours at 210-275 C, and since the thermal reaction of the phenylethynyl group does not occur to any appreciable extent at temperatures below 300 C, these materials have a broad processing window. Upon thermal cure at approximately 300-350 C, the phenylethynyl groups react to provide a crosslinked resin system. These new materials exhibit excellent properties and are potentially useful as adhesives, coatings, films, moldings and composite matrices.

  19. Hydrogen sulfide at high pressure: change in stoichiometry

    NASA Astrophysics Data System (ADS)

    Goncharov, Alexander; Lobanov, Sergey; Kruglov, Ivan; Zhao, Xiao-Miao; Chen, Xiao-Jia; Oganov, Artem; Konopkova, Zuzana; Prakapenka, Vitali

    Hydrogen sulfide (H2S) was studied by x-ray synchrotron diffraction (XRD) and Raman spectroscopy up to 144 GPa at 180-295 K. We find that H2S compound become unstable with respect to formation of new compounds with different composition including pure S, H3S and HS2 depending on the thermodynamic P-T path. These results are supported by our quantum-mechanical variable-composition evolutionary simulations that show the stability of the above mentioned compounds at elevated pressures. The stability of H3S at high pressures, which we find a strong experimental and theoretical confirmation here, suggests that it is this material which is responsible for high-temperature superconducting properties reported previously. We thank DARPA, NSF, ISSP (Hefei, China), Government of Russian Federation, and Foreign Talents Introduction and Academic Exchange Program. Use of the Advanced Photon Source was supported by the U. S. Department of Energy Office of Science.

  20. Hydrogen sulfide at high pressure: Change in stoichiometry

    NASA Astrophysics Data System (ADS)

    Goncharov, Alexander F.; Lobanov, Sergey S.; Kruglov, Ivan; Zhao, Xiao-Miao; Chen, Xiao-Jia; Oganov, Artem R.; Konôpková, Zuzana; Prakapenka, Vitali B.

    2016-05-01

    Hydrogen sulfide (H2S ) was studied by x-ray synchrotron diffraction and Raman spectroscopy up to 150 GPa at 180-295 K and by quantum-mechanical variable-composition evolutionary simulations. The experiments show that H2S becomes unstable with respect to formation of compounds with different structure and composition, including Cccm and a body-centered cubic like (R 3 m or I m -3 m ) H3S , the latter one predicted previously to show a record-high superconducting transition temperature, a Tc of 203 K. These experiments provide experimental ground for understanding of this record-high Tc. The experimental results are supported by theoretical structure searches that suggest the stability of H3S , H4S3 , H5S8 , H3S5 , and H S2 compounds that have not been reported previously at elevated pressures.

  1. Hydrogen permeability of thin condensed Pd-Cu foil: Dependence on temperature and phase composition

    NASA Astrophysics Data System (ADS)

    Ievlev, V. M.; Solntsev, K. A.; Dontsov, A. I.; Maksimenko, A. A.; Kannykin, S. V.

    2016-03-01

    The hydrogen permeability of thin (about 4 μm thick) magnetron-sputtered Pd-Cu foil and structural transformations during temperature cycling (heating-cooling process) are studied. It is found that the hydrogen permeability is maximal when the content of the β-phase is 100%. Upon annealing of Pd-Cu alloy in hydrogen, the temperature range where a regular structure exists expands.

  2. A new model of hydrogen redistribution in Zr alloy claddings during waterside corrosion in a temperature gradient

    NASA Astrophysics Data System (ADS)

    Veshchunov, M. S.; Shestak, V. E.; Ozrin, V. D.

    2016-04-01

    A new model for hydrogen spatial redistribution and hydride precipitation in Zr alloys during waterside corrosion extends the traditional approach, valid for consideration of a relatively low volume fraction of the precipitated hydride phase, to a more general case of heavily precipitated hydrides typical for high-burnup fuel cladding tubes of pressurized water reactors and also observed in various autoclave corrosion tests with high hydrogen supercharging. Being implemented in the SVECHA/QUENCH (S/Q) code, the new model reasonably explains various observations in corrosion tests at constant temperature and under temperature gradient as well as under in-reactor corrosion conditions.

  3. A high-efficiency power cycle in which hydrogen is compressed by absorption in metal hydrides.

    PubMed

    Powell, J R; Salzano, F J; Yu, W S; Milau, J S

    1976-07-23

    A high-efficiency power cycle is proposed in which molecular hydrogen gas is used as a working fluid in a regenerative closed Brayton cycle. The hydrogen gas is compressed by an absorption-desorption cycle on metal hydride (FeTiH(x)) beds. Low-temperature solar or geothermal heat (temperature about 100 degrees C) is used for the compression process, and high-temperature fossil fuel or nuclear heat (temperature about 700 degrees C) supplies the expansion work in the turbine. Typically, about 90 percent of the high-temperature heat input is converted to electricity, while about 3 kilowatts of low-temperature heat is required per kilowatt of electrical output. PMID:17745726

  4. The Potential for Low-Temperature Abiotic Hydrogen Generation and a Hydrogen-Driven Deep Biosphere

    PubMed Central

    Huang, Shanshan; Thorseth, Ingunn H.

    2011-01-01

    Abstract The release and oxidation of ferrous iron during aqueous alteration of the mineral olivine is known to reduce aqueous solutions to such extent that molecular hydrogen, H2, forms. H2 is an efficient energy carrier and is considered basal to the deep subsurface biosphere. Knowledge of the potential for H2 generation is therefore vital to understanding the deep biosphere on Earth and on extraterrestrial bodies. Here, we provide a review of factors that may reduce the potential for H2 generation with a focus on systems in the core temperature region for thermophilic to hyperthermophilic microbial life. We show that aqueous sulfate may inhibit the formation of H2, whereas redox-sensitive compounds of carbon and nitrogen are unlikely to have significant effect at low temperatures. In addition, we suggest that the rate of H2 generation is proportional to the dissolution rate of olivine and, hence, limited by factors such as reactive surface areas and the access of water to fresh surfaces. We furthermore suggest that the availability of water and pore/fracture space are the most important factors that limit the generation of H2. Our study implies that, because of large heat flows, abundant olivine-bearing rocks, large thermodynamic gradients, and reduced atmospheres, young Earth and Mars probably offered abundant systems where microbial life could possibly have emerged. Key Words: Serpentinization—Olivine—Hydrogen—Deep biosphere—Water—Mars. Astrobiology 11, 711–724. PMID:21923409

  5. NSTX High Temperature Sensor Systems

    SciTech Connect

    B.McCormack; H.W. Kugel; P. Goranson; R. Kaita; et al

    1999-11-01

    The design of the more than 300 in-vessel sensor systems for the National Spherical Torus Experiment (NSTX) has encountered several challenging fusion reactor diagnostic issues involving high temperatures and space constraints. This has resulted in unique miniature, high temperature in-vessel sensor systems mounted in small spaces behind plasma facing armor tiles, and they are prototypical of possible high power reactor first-wall applications. In the Center Stack, Divertor, Passive Plate, and vessel wall regions, the small magnetic sensors, large magnetic sensors, flux loops, Rogowski Coils, thermocouples, and Langmuir Probes are qualified for 600 degrees C operation. This rating will accommodate both peak rear-face graphite tile temperatures during operations and the 350 degrees C bake-out conditions. Similar sensor systems including flux loops, on other vacuum vessel regions are qualified for 350 degrees C operation. Cabling from the sensors embedded in the graphite tiles follows narrow routes to exit the vessel. The detailed sensor design and installation methods of these diagnostic systems developed for high-powered ST operation are discussed.

  6. Simulation of Liquid Level, Temperature and Pressure Inside a 2000 Liter Liquid Hydrogen Tank During Truck Transportation

    NASA Astrophysics Data System (ADS)

    Takeda, Minoru; Nara, Hiroyuki; Maekawa, Kazuma; Fujikawa, Shizuichi; Matsuno, Yu; Kuroda, Tsuneo; Kumakura, Hiroaki

    Hydrogen is an ultimate energy source because only water is produced after the chemical reaction of hydrogen and oxygen. In the near future, a large amount of hydrogen, produced using sustainable/renewable energy, is expected to be consumed. Since liquid hydrogen (LH2) has the advantage of high storage efficiency, it is expected to be the ultimate medium for the worldwide storage and transportation of large amounts of hydrogen. To make a simulation model of the sloshing of LH2 inside a 2000 liter tank, simulation analyses of LH2 surface oscillation, temperature and pressure inside the tank during a truck transportation have been carried out using a multipurpose software ANSYS CFX. Numerical results are discussed in comparison with experimental results.

  7. Rhodium dihydride (RhH[subscript 2]) with high volumetric hydrogen density

    SciTech Connect

    Li, Bing; Ding, Yang; Kim, Duck Young; Ahuja, Rajeev; Zou, Guangtian; Mao, Ho-Kwang

    2012-03-14

    Materials with very high hydrogen density have attracted considerable interest due to a range of motivations, including the search for chemically precompressed metallic hydrogen and hydrogen storage applications. Using high-pressure synchrotron X-ray diffraction technique and theoretical calculations, we have discovered a new rhodium dihydride (RhH{sub 2}) with high volumetric hydrogen density (163.7 g/L). Compressing rhodium in fluid hydrogen at ambient temperature, the fcc rhodium metal absorbs hydrogen and expands unit-cell volume by two discrete steps to form NaCl-typed fcc rhodium monohydride at 4 GPa and fluorite-typed fcc RhH{sub 2} at 8 GPa. RhH{sub 2} is the first dihydride discovered in the platinum group metals under high pressure. Our low-temperature experiments show that RhH{sub 2} is recoverable after releasing pressure cryogenically to 1 bar and is capable of retaining hydrogen up to 150 K for minutes and 77 K for an indefinite length of time.

  8. Rhodium dihydride (RhH2) with high volumetric hydrogen density

    PubMed Central

    Li, Bing; Ding, Yang; Kim, Duck Young; Ahuja, Rajeev; Zou, Guangtian; Mao, Ho-Kwang

    2011-01-01

    Materials with very high hydrogen density have attracted considerable interest due to a range of motivations, including the search for chemically precompressed metallic hydrogen and hydrogen storage applications. Using high-pressure synchrotron X-ray diffraction technique and theoretical calculations, we have discovered a new rhodium dihydride (RhH2) with high volumetric hydrogen density (163.7 g/L). Compressing rhodium in fluid hydrogen at ambient temperature, the fcc rhodium metal absorbs hydrogen and expands unit-cell volume by two discrete steps to form NaCl-typed fcc rhodium monohydride at 4 GPa and fluorite-typed fcc RhH2 at 8 GPa. RhH2 is the first dihydride discovered in the platinum group metals under high pressure. Our low-temperature experiments show that RhH2 is recoverable after releasing pressure cryogenically to 1 bar and is capable of retaining hydrogen up to 150 K for minutes and 77 K for an indefinite length of time. PMID:22039219

  9. Hydrogen-bonds structure in poly(2-hydroxyethyl methacrylate) studied by temperature-dependent infrared spectroscopy

    PubMed Central

    Morita, Shigeaki

    2014-01-01

    Hydrogen-bonds structure in poly(2-hydroxyethyl methacrylate) (PHEMA) were investigated by means of temperature-dependent infrared (IR) spectroscopy. Spectral variations involved with the OH…OH and C=O…HO types of hydrogen-bonds were found around the glass transition temperature of 80°C. Hydrogen-bonds among the hydroxyl groups gradually dissociate with increasing temperature. In contrast, discontinuous variation in the carbonyl bands was observed around the glass transition temperature. An association of the C=O…HO type of hydrogen-bond with increasing temperature above the glass transition temperature was revealed. These were concluded from the present study that hydrogen-bonds among the hydroxyl groups in each side chain terminal suppress the main chain mobility in the polymer matrix below the glass transition temperature, while the dissociation of the OH…OH type of hydrogen-bonds induces the association of the C=O…HO type of hydrogen-bond. As a result, the mobility of the main chain is induced by the change in hydrogen-bonds structure at the glass transition temperature. PMID:24790979

  10. Hydrogen-Bonds Structure in Poly(2-Hydroxyethyl Methacrylate) Studied by Temperature-Dependent Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Morita, Shigeaki

    2014-03-01

    Hydrogen-bonds structure in poly(2-hydroxyethyl methacrylate) (PHEMA) were investigated by means of temperature-dependent infrared (IR) spectroscopy. Spectral variations involved with the OH•••OH and C=O•••HO types of hydrogen-bonds were found around the glass transition temperature of 80 °C. Hydrogen-bonds among the hydroxyl groups gradually dissociate with increasing temperature. In contrast, discontinuous variation in the carbonyl bands was observed around the glass transition temperature. An association of the C=O•••HO type of hydrogen-bond with increasing temperature above the glass transition temperature was revealed. These were concluded from the present study that hydrogen-bonds among the hydroxyl groups in each side chain terminal suppress the main chain mobility in the polymer matrix below the glass transition temperature, while the dissociation of the OH•••OH type of hydrogen-bonds induces the association of the C=O•••HO type of hydrogen-bond. As a result, the mobility of the main chain is induced by the change in hydrogen-bonds structure at the glass transition temperature.

  11. High temperature two component explosive

    DOEpatents

    Mars, James E.; Poole, Donald R.; Schmidt, Eckart W.; Wang, Charles

    1981-01-01

    A two component, high temperature, thermally stable explosive composition comprises a liquid or low melting oxidizer and a liquid or low melting organic fuel. The oxidizer and fuel in admixture are incapable of substantial spontaneous exothermic reaction at temperatures on the order of 475.degree. K. At temperatures on the order of 475.degree. K., the oxidizer and fuel in admixture have an activation energy of at least about 40 kcal/mol. As a result of the high activation energy, the preferred explosive compositions are nondetonable as solids at ambient temperature, and become detonable only when heated beyond the melting point. Preferable oxidizers are selected from alkali or alkaline earth metal nitrates, nitrites, perchlorates, and/or mixtures thereof. Preferred fuels are organic compounds having polar hydrophilic groups. The most preferred fuels are guanidinium nitrate, acetamide and mixtures of the two. Most preferred oxidizers are eutectic mixtures of lithium nitrate, potassium nitrate and sodium nitrate, of sodium nitrite, sodium nitrate and potassium nitrate, and of potassium nitrate, calcium nitrate and sodium nitrate.

  12. High-Temperature Proton-Conducting Ceramics Developed

    NASA Technical Reports Server (NTRS)

    Sayir, Ali; Dynys, Frederick W.; Berger, M. H.

    2005-01-01

    High-temperature protonic conductors (HTPC) are needed for hydrogen separation, hydrogen sensors, fuel cells, and hydrogen production from fossil fuels. The HTPC materials for hydrogen separation at high temperatures are foreseen to be metal oxides with the perovskite structure A(sup 2+)B(sup 4+)C(sup 2-, sub 3) and with the trivalent cation (M(sup 3+)) substitution at the B(sup 4+)-site to introduce oxygen vacancies. The high affinity for hydrogen ions (H(sup +)) is advantageous for protonic transport, but it increases the reactivity toward water (H2O) and carbon dioxide (CO2), which can lead to premature membrane failure. In addition, there are considerable technological challenges related to the processing of HTPC materials. The high melting point and multi-cation chemistry of HTPC materials creates difficulties in in achieving high-density, single-phase membranes by solid-state sintering. The presence of secondary phases and grain-boundary interfaces are detrimental to the protonic conduction and environmental stability of polycrystalline HTPC materials.

  13. Magnetic ordering temperature of nanocrystalline Gd: enhancement of magnetic interactions via hydrogenation-induced “negative” pressure

    NASA Astrophysics Data System (ADS)

    Tereshina, E. A.; Khmelevskyi, S.; Politova, G.; Kaminskaya, T.; Drulis, H.; Tereshina, I. S.

    2016-03-01

    Gadolinium is a nearly ideal soft-magnetic material. However, one cannot take advantage of its properties at temperatures higher than the room temperature where Gd loses the ferromagnetic ordering. By using high-purity bulk samples with grains ~200 nm in size, we present proof-of-concept measurements of an increased Curie point (TC) and spontaneous magnetization in Gd due to hydrogenation. From first-principles we explain increase of TC in pure Gd due to the addition of hydrogen. We show that the interplay of the characteristic features in the electronic structure of the conduction band at the Fermi level in the high-temperature paramagnetic phase of Gd and “negative” pressure exerted by hydrogen are responsible for the observed effect.

  14. Magnetic ordering temperature of nanocrystalline Gd: enhancement of magnetic interactions via hydrogenation-induced “negative” pressure

    PubMed Central

    Tereshina, E. A.; Khmelevskyi, S.; Politova, G.; Kaminskaya, T.; Drulis, H.; Tereshina, I. S.

    2016-01-01

    Gadolinium is a nearly ideal soft-magnetic material. However, one cannot take advantage of its properties at temperatures higher than the room temperature where Gd loses the ferromagnetic ordering. By using high-purity bulk samples with grains ~200 nm in size, we present proof-of-concept measurements of an increased Curie point (TC) and spontaneous magnetization in Gd due to hydrogenation. From first-principles we explain increase of TC in pure Gd due to the addition of hydrogen. We show that the interplay of the characteristic features in the electronic structure of the conduction band at the Fermi level in the high-temperature paramagnetic phase of Gd and “negative” pressure exerted by hydrogen are responsible for the observed effect. PMID:26931775

  15. Tellurium Hydrides at High Pressures: High-Temperature Superconductors

    NASA Astrophysics Data System (ADS)

    Zhong, Xin; Wang, Hui; Zhang, Jurong; Liu, Hanyu; Zhang, Shoutao; Song, Hai-Feng; Yang, Guochun; Zhang, Lijun; Ma, Yanming

    2016-02-01

    Observation of high-temperature superconductivity in compressed sulfur hydrides has generated an irresistible wave of searches for new hydrogen-containing superconductors. We herein report the prediction of high-Tc superconductivity in tellurium hydrides stabilized at megabar pressures identified by first-principles calculations in combination with a swarm structure search. Although tellurium is isoelectronic to sulfur or selenium, its heavier atomic mass and weaker electronegativity makes tellurium hydrides fundamentally distinct from sulfur or selenium hydrides in stoichiometries, structures, and chemical bondings. We identify three metallic stoichiometries of H4Te , H5Te2 , and HTe3 , which are not predicted or known stable structures for sulfur or selenium hydrides. The two hydrogen-rich H4Te and H5Te2 phases are primarily ionic and contain exotic quasimolecular H2 and linear H3 units, respectively. Their high-Tc (e.g., 104 K for H4Te at 170 GPa) superconductivity originates from the strong electron-phonon couplings associated with intermediate-frequency H-derived wagging and bending modes, a superconducting mechanism which differs substantially with those in sulfur or selenium hydrides where the high-frequency H-stretching vibrations make considerable contributions.

  16. Tellurium Hydrides at High Pressures: High-Temperature Superconductors.

    PubMed

    Zhong, Xin; Wang, Hui; Zhang, Jurong; Liu, Hanyu; Zhang, Shoutao; Song, Hai-Feng; Yang, Guochun; Zhang, Lijun; Ma, Yanming

    2016-02-01

    Observation of high-temperature superconductivity in compressed sulfur hydrides has generated an irresistible wave of searches for new hydrogen-containing superconductors. We herein report the prediction of high-T_{c} superconductivity in tellurium hydrides stabilized at megabar pressures identified by first-principles calculations in combination with a swarm structure search. Although tellurium is isoelectronic to sulfur or selenium, its heavier atomic mass and weaker electronegativity makes tellurium hydrides fundamentally distinct from sulfur or selenium hydrides in stoichiometries, structures, and chemical bondings. We identify three metallic stoichiometries of H_{4}Te, H_{5}Te_{2}, and HTe_{3}, which are not predicted or known stable structures for sulfur or selenium hydrides. The two hydrogen-rich H_{4}Te and H_{5}Te_{2} phases are primarily ionic and contain exotic quasimolecular H_{2} and linear H_{3} units, respectively. Their high-T_{c} (e.g., 104 K for H_{4}Te at 170 GPa) superconductivity originates from the strong electron-phonon couplings associated with intermediate-frequency H-derived wagging and bending modes, a superconducting mechanism which differs substantially with those in sulfur or selenium hydrides where the high-frequency H-stretching vibrations make considerable contributions. PMID:26894729

  17. Motor for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Roopnarine (Inventor)

    2013-01-01

    A high temperature motor has a stator with poles formed by wire windings, and a rotor with magnetic poles on a rotor shaft positioned coaxially within the stator. The stator and rotor are built up from stacks of magnetic-alloy laminations. The stator windings are made of high temperature magnet wire insulated with a vitreous enamel film, and the wire windings are bonded together with ceramic binder. A thin-walled cylinder is positioned coaxially between the rotor and the stator to prevent debris from the stator windings from reaching the rotor. The stator windings are wound on wire spools made of ceramic, thereby avoiding need for mica insulation and epoxy/adhesive. The stator and rotor are encased in a stator housing with rear and front end caps, and rear and front bearings for the rotor shaft are mounted on external sides of the end caps to keep debris from the motor migrating into the bearings' races.

  18. Infrared spectroscopy of hydrogenated fullerenes (fulleranes) at extreme temperatures

    NASA Astrophysics Data System (ADS)

    Iglesias-Groth, Susana; García-Hernández, D. A.; Cataldo, Franco; Manchado, Arturo

    2012-07-01

    The infrared spectra, as well as the integrated molar absorptivity (Ψ) and the molar extinction coefficient (ɛ) of each infrared transition of the hydrogenated fullerenes (known as fulleranes) C60H36, C60H18 and C70H38, and a mixture of fulleranes generally referred to as 77 per cent of C60Hx and 22 per cent C70Hy with x≈y > 30, are presented and discussed. These data are useful for the search, identification and quantitative determination of fulleranes in space after the recent discovery that their parent molecules, C60 and C70, are more abundant in space than initially thought, being present in a variety of H-rich circumstellar environments such as planetary nebulae and only mild H-deficient R Coronae Borealis stars, and in the interstellar medium. It is shown that the C-H stretching band of the fulleranes C60H36, C60H18 and C70H38, and their mixture may be most useful for the identification of these molecules because their Ψ and ɛ values are unique in terms of strength, overcoming by far the typical Ψ and ɛ values of reference molecules such as adamantane and docosane, as well as typical ɛ literature data for aliphatic molecules. In contrast to the rather simple infrared spectra of C60H36 and C60H38, the infrared spectra of two C60H18 isomers are reported as characterized by a rich number of bands which may allow an easier identification than the higher homologues. The dependence of the infrared bands of fulleranes on temperature was studied over a wide range of temperatures (from -180°C to +250°C) and extrapolated to 0 K.

  19. Hydrogenation under high pressure enhancing catalytic activity of Cu-Zr amorphous alloys

    NASA Astrophysics Data System (ADS)

    Szummer, A.; Janik-Czachor, M.; Molnár, Á.; Marchuk, I.; Varga, M.; Filipek, S. M.

    2002-11-01

    High pressures of hydrogen up to 3.0 GPa and temperatures up to 373 K were used as a pretreatment to introduce structural changes in the bulk and on the surface of Cu-Zr amorphous alloys which then were examined by means of x-ray diffraction and microscopy. The hydrogenative pretreatment of high hydrogen fugacity followed by annealing at 623 K, aimed at causing desorption of hydrogen, and an eventual exposure of the samples to air at room temperature to oxidize Zr, resulted in a distinct increase of catalytic activity in the dehydrogenation of 2-propanol. A tentative mechanism to account for the enhancement of the catalytic activity induced by the above combined pretreatment is discussed.

  20. High pressure and high temperature apparatus

    DOEpatents

    Voronov, Oleg A.

    2005-09-13

    A design for high pressure/high temperature apparatus and reaction cell to achieve .about.30 GPa pressure in .about.1 cm volume and .about.100 GPa pressure in .about.1 mm volumes and 20-5000.degree. C. temperatures in a static regime. The device includes profiled anvils (28) action on a reaction cell (14, 16) containing the material (26) to be processed. The reaction cell includes a heater (18) surrounded by insulating layers and screens. Surrounding the anvils are cylindrical inserts and supporting rings (30-48) whose hardness increases towards the reaction cell. These volumes may be increased considerably if applications require it, making use of presses that have larger loading force capability, larger frames and using larger anvils.

  1. High-Temperature Polyimide Resin

    NASA Technical Reports Server (NTRS)

    Vanucci, Raymond D.; Malarik, Diane C.

    1990-01-01

    Improved polyimide resin used at continuous temperatures up to 700 degrees F (371 degrees C). PMR-II-50, serves as matrix for fiber-reinforced composites. Material combines thermo-oxidative stability with autoclave processability. Used in such turbine engine components as air-bypass ducts, vanes, bearings, and nozzle flaps. Other potential applications include wing and fuselage skins on high-mach-number aircraft and automotive engine blocks and pistons.

  2. HIGH TEMPERATURE MICROSCOPE AND FURNACE

    DOEpatents

    Olson, D.M.

    1961-01-31

    A high-temperature microscope is offered. It has a reflecting optic situated above a molten specimen in a furnace and reflecting the image of the same downward through an inert optic member in the floor of the furnace, a plurality of spaced reflecting plane mirrors defining a reflecting path around the furnace, a standard microscope supported in the path of and forming the end terminus of the light path.

  3. High-temperature structural ceramics.

    PubMed

    Katz, R N

    1980-05-23

    The unique properties of ceramics based on silicon carbide and silicon nitride make them prime candidates for use in advanced energy conversion systems. These compounds are the bases for broad families of engineering materials, whose properties are reviewed. The relationships between processing, microstructure, and properties are discussed. A review and assessment of recent progress in the use of these materials in high-temperature engineering systems, and vehicular engines in particular, is presented. PMID:17772807

  4. High-temperature geothermal cableheads

    SciTech Connect

    Coquat, J.A.; Eifert, R.W.

    1981-11-01

    Two high-temperature, corrosion-resistant logging cableheads which use metal seals and a stable fluid to achieve proper electrical terminations and cable-sonde interfacings are described. A tensile bar provides a calibrated yield point, and a cone assembly anchors the cable armor to the head. Electrical problems of the sort generally ascribable to the cable-sonde interface were absent during demonstration hostile-environment loggings in which these cableheads were used.

  5. High temperature solar thermal receiver

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A design concept for a high temperature solar thermal receiver to operate at 3 atmospheres pressure and 2500 F outlet was developed. The performance and complexity of windowed matrix, tube-header, and extended surface receivers were evaluated. The windowed matrix receiver proved to offer substantial cost and performance benefits. An efficient and cost effective hardware design was evaluated for a receiver which can be readily interfaced to fuel and chemical processes or to heat engines for power generation.

  6. High temperature turbine engine structure

    DOEpatents

    Carruthers, William D.; Boyd, Gary L.

    1993-01-01

    A high temperature ceramic/metallic turbine engine includes a metallic housing which journals a rotor member of the turbine engine. A ceramic disk-like shroud portion of the engine is supported on the metallic housing portion and maintains a close running clearance with the rotor member. A ceramic spacer assembly maintains the close running clearance of the shroud portion and rotor member despite differential thermal movements between the shroud portion and metallic housing portion.

  7. High temperature turbine engine structure

    DOEpatents

    Carruthers, William D.; Boyd, Gary L.

    1992-01-01

    A high temperature ceramic/metallic turbine engine includes a metallic housing which journals a rotor member of the turbine engine. A ceramic disk-like shroud portion of the engine is supported on the metallic housing portion and maintains a close running clearance with the rotor member. A ceramic spacer assembly maintains the close running clearance of the shroud portion and rotor member despite differential thermal movements between the shroud portion and metallic housing portion.

  8. High temperature turbine engine structure

    DOEpatents

    Carruthers, William D.; Boyd, Gary L.

    1994-01-01

    A high temperature ceramic/metallic turbine engine includes a metallic housing which journals a rotor member of the turbine engine. A ceramic disk-like shroud portion of the engine is supported on the metallic housing portion and maintains a close running clearance with the rotor member. A ceramic spacer assembly maintains the close running clearance of the shroud portion and rotor member despite differential thermal movements between the shroud portion and metallic housing portion.

  9. 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.

  10. Finite-Temperature Hydrogen Adsorption/Desorption Thermodynamics Driven by Soft Vibration Modes

    SciTech Connect

    Woo, Sung-Jae; Lee, Eui-Sup; Yoon, Mina; Yong-Hyun, Kim

    2013-01-01

    It is widely accepted that room-temperature hydrogen storage on nanostructured or porous materials requires enhanced dihydrogen adsorption. In this work we reveal that room-temperature hydrogen storage is possible not only by the enhanced adsorption, but also by making use of the vibrational free energy from soft vibration modes. These modes exist for example in the case of metallo-porphyrin-incorporated graphenes (M-PIGs) with out-of-plane ( buckled ) metal centers. There, the in-plane potential surfaces are flat because of multiple-orbital-coupling between hydrogen molecules and the buckled-metal centers. This study investigates the finite-temperature adsorption/desorption thermodynamics of hydrogen molecules adsorbed on M-PIGs by employing first-principles total energy and vibrational spectrum calculations. Our results suggest that the current design strategy for room-temperature hydrogen storage materials should be modified by explicitly taking finite-temperature vibration thermodynamics into account.

  11. High Efficient Cryocooler for Liquid Hydrogen System

    NASA Astrophysics Data System (ADS)

    Nakagome, H.

    2006-04-01

    Conversion into Hydrogen Energy Society is advanced focusing on the application to a fuel cell electric vehicle. As volume and weight density of liquid hydrogen are large, it is the method which was most excellent as the storage method of hydrogen. However, in order to store liquid hydrogen stably over a long period of time, decreasing the loss of energy, development of an efficient small cryocooler becomes important. This paper reports the research about improvement in the refrigeration efficiency of a two-stage GM cryocooler. In order that the GM cryocooler may operate by the Simon expansion, it carries out asymptotic of the COP of the GM cryocooler to the Carnot COP as a compression ratio is lowered. When experimented based on this view, it was checked that refrigeration efficiency rises with reduction in a compression ratio. Furthermore, if the compression ratio is lowered, refrigeration efficiency will fall rapidly. The peak value of the refrigeration efficiency in 20K level attained 28%Carnot. It was verified by optimization of the compression ratio of the GM cryocooler that refrigeration efficiency can be improved significantly. Therefore, sharp reduction of the energy consumption of a liquid hydrogen system will be attained by applying the result of this research.

  12. Metalized T graphene: A reversible hydrogen storage material at room temperature

    SciTech Connect

    Ye, Xiao-Juan; Zhong, Wei E-mail: wzhong@nju.edu.cn; Du, You-Wei; Liu, Chun-Sheng E-mail: wzhong@nju.edu.cn; Zeng, Zhi

    2014-09-21

    Lithium (Li)-decorated graphene is a promising hydrogen storage medium due to its high capacity. However, homogeneous mono-layer coating graphene with lithium atoms is metastable and the lithium atoms would cluster on the surface, resulting in the poor reversibility. Using van der Waals-corrected density functional theory, we demonstrated that lithium atoms can be homogeneously dispersed on T graphene due to a nonuniform charge distribution in T graphene and strong hybridizations between the C-2p and Li-2p orbitals. Thus, Li atoms are not likely to form clusters, indicating a good reversible hydrogen storage. Both the polarization mechanism and the orbital hybridizations contribute to the adsorption of hydrogen molecules (storage capacity of 7.7 wt. %) with an optimal adsorption energy of 0.19 eV/H₂. The adsorption/desorption of H₂ at ambient temperature and pressure is also discussed. Our results can serve as a guide in the design of new hydrogen storage materials based on non-hexagonal graphenes.

  13. Deposition method for producing silicon carbide high-temperature semiconductors

    DOEpatents

    Hsu, George C.; Rohatgi, Naresh K.

    1987-01-01

    An improved deposition method for producing silicon carbide high-temperature semiconductor material comprising placing a semiconductor substrate composed of silicon carbide in a fluidized bed silicon carbide deposition reactor, fluidizing the bed particles by hydrogen gas in a mildly bubbling mode through a gas distributor and heating the substrate at temperatures around 1200.degree.-1500.degree. C. thereby depositing a layer of silicon carbide on the semiconductor substrate.

  14. Device separates hydrogen from solution in water at ambient temperatures

    NASA Technical Reports Server (NTRS)

    Albright, C. F.

    1969-01-01

    Separator decreases the partial pressure of hydrogen gas dissolved in the water produced by fuel cells containing an alkaline electrolyte. The unit eliminates the hazards associated with the release of hydrogen from water solution when the hydrostatic pressure is rapidly decreased.

  15. HITCAN: High temperature composite analyzer

    NASA Technical Reports Server (NTRS)

    Singhal, Surendra N.; Lackney, Joseph J.; Chamis, Christos C.; Murthy, Pappu L. N.

    1990-01-01

    A computer code, HITCAN (High Temperature Composite Analyzer) was developed to analyze/design metal matrix composite structures. HITCAN is based on composite mechanics theories and computer codes developed at NASA LeRC over the last two decades. HITCAN is a general purpose code for predicting the global structural and local stress-strain response of multilayered (arbitrarily oriented) metal matrix structures both at the constituent (fiber, matrix, and interphase) and the structure level and including the fabrication process effects. The thermomechanical properties of the constituents are considered to be nonlinearly dependent on several parameters including temperature, stress, and stress rate. The computational procedure employs an incremental iterative nonlinear approach utilizing a multifactor-interaction material behavior model. HITCAN features and analysis capabilities (static, load stepping, modal, and buckling) are demonstrated through typical example problems.

  16. Compensated High Temperature Strain Gage

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A device for measuring strain in substrates at high temperatures in which the thermally induced apparent strain is nulled is described. Two gages are used, one active gage and one compensating gage. Both gages are placed on the substrate to be gaged; the active gage is attached such that it responds to mechanical and thermally induced apparent strain while the compensating gage is attached such that it does not respond to mechanical strain and and measures only thermally induced apparent strain. A thermal blanket is placed over the two gages to maintain the gages at the same temperature. The two gages are wired as adjacent arms of a wheatstone bridge which nulls the thermally induced apparent strain giving a true reading of the mechanical strain in the substrate.

  17. Alloy performance in high temperature oil refining environments

    SciTech Connect

    Sorell, G.; Humphries, M.J.; McLaughlin, J.E.

    1995-12-31

    The performance of steels and alloys in high temperature petroleum refining applications is strongly influenced by detrimental interactions with aggressive process environments. These are encountered in conventional refining processes and especially in processing schemes for fuels conversion and upgrading. Metal-environment interactions can shorten equipment life and cause impairment of mechanical properties, metallurgical stability and weldability. Corrosion and other high temperature attack modes discussed are sulfidation, hydrogen attack, carburization, and metal dusting. Sulfidation is characterized by bulky scales that are generally ineffective corrosion barriers. Metal loss is often accompanied by sub-surface sulfide penetration. Hydrogen attack and carburization proceed without metal loss and are detectable only by metallographic examination. In advanced stages, these deterioration modes cause severe impairment of mechanical properties. Harmful metal-environment interactions are characterized and illustrated with data drawn from test exposures and plant experience. Alloys employed for high temperature oil refining equipment are identified, including some promising newcomers.

  18. Effects of deposition temperature on the effectiveness of hydrogen doping in Ga-doped ZnO thin films

    SciTech Connect

    Kim, Dong-Ho; Lee, Sung-Hun; Lee, Gun-Hwan; Kim, Hyun-Bum; Kim, Kwang Ho; Lee, Yoon-Gyu; Yu, Tae-Hwan

    2010-07-15

    Gallium-doped zinc oxide thin films were prepared on glass substrates by dc magnetron sputtering under various hydrogen contents in sputtering ambient. The carrier concentration of the films deposited at low-temperatures (80 and 160 deg. C) was increased due to the incorporation of hydrogen atoms, acting as shallow donors. A low resistivity of 4.0x10{sup -4} {Omega} cm was obtained for the film grown at 160 deg. C with H{sub 2} 10%, which has a carrier concentration of 8.2x10{sup 20}/cm{sup 3}. The beneficial effect of hydrogen doping was not observed for the films deposited at 270 deg. C. Both carrier concentration and mobility were decreased by the addition of hydrogen gas in the sputtering ambient. Variations in the electrical transport properties upon vacuum annealing showed that the difference is attributed to the thermal stability of interstitial hydrogen atoms in the films. The hydrogen incorporation was found to induce the lattice expansion and the free carrier absorption in near infrared range. The investigation of the structural and optical properties of the films upon annealing also revealed that the incorporated hydrogen atoms are unstable at high temperature, which is consistent with the results obtained in the electrical properties.

  19. Two-dimensional Raman mole-fraction and temperature measurements for hydrogen-nitrogen mixture analysis.

    PubMed

    Braeuer, Andreas; Leipertz, Alfred

    2009-02-01

    A two-dimensional laser Raman technique was developed and applied to directly probe the population number of selected rotational and vibrational energy levels of hydrogen and nitrogen. Using three cameras simultaneously, temperature and mole fraction images could be detected. Three different combinations of rotational and vibrational Raman signals of hydrogen and nitrogen were analyzed to identify the combination that is most suitable for future mixture analysis in hydrogen internal combustion engines. Here the experiments were conducted in an injection chamber where hot hydrogen was injected into room temperature nitrogen at 1.1 MPa. PMID:19183582

  20. Effective hydrodynamic hydrogen escape from an early Earth atmosphere inferred from high-accuracy numerical simulation

    NASA Astrophysics Data System (ADS)

    Kuramoto, Kiyoshi; Umemoto, Takafumi; Ishiwatari, Masaki

    2013-08-01

    Hydrodynamic escape of hydrogen driven by solar extreme ultraviolet (EUV) radiation heating is numerically simulated by using the constrained interpolation profile scheme, a high-accuracy scheme for solving the one-dimensional advection equation. For a wide range of hydrogen number densities at the lower boundary and solar EUV fluxes, more than half of EUV heating energy is converted to mechanical energy of the escaping hydrogen. Less energy is lost by downward thermal conduction even giving low temperature for the atmospheric base. This result differs from a previous numerical simulation study that yielded much lower escape rates by employing another scheme in which relatively strong numerical diffusion is implemented. Because the solar EUV heating effectively induces hydrogen escape, the hydrogen mixing ratio was likely to have remained lower than 1 vol% in the anoxic Earth atmosphere during the Archean era.

  1. Temperature measurements and hydrogen transformation under dynamic compression up to 150 GPA.

    NASA Astrophysics Data System (ADS)

    Nikolaev, Dmitry; Pyalling, Alexey; Kvitov, Sergey; Fortov, Vladimir

    2012-03-01

    Lithium fluoride single crystal window was used for optical light emission registration during quasi-isentropic compression of hydrogen to the pressures 100-150 GPa. Initially gaseous hydrogen samples at 78 K temperature and different pressures in the range 3-30 MPa were investigated. Recorded brightness temperature profiles in near infrared range of wavelength were analyzed to evaluate optical and transport properties of the investigated hydrogen sample and window. Two EOS models of hydrogen, with and without metallic region were used for 1-D simulation of it's properties under dynamic compression and estimation of hydrogen temperature within compressed layer. The obtained data demonstrate abrupt change of final temperatures after heating higher then 3500K.

  2. Temperature measurements and hydrogen transformation under dynamic compression up to 150 GPa

    NASA Astrophysics Data System (ADS)

    Dmitry, Nikolaev; Vladimir, Ternovoi; Alexei, Pyalling; Sergey, Kvitov; Vladimir, Fortov

    2011-06-01

    Lithium fluoride single crystal window was used for registration of optical light emission during quasi-isentropic compression of hydrogen to the pressures 100-150 GPa. Initially gaseous hydrogen samples at 78 K temperature and different pressures in the range 4-30 MPa were investigated. Recorded brightness temperature profiles at near infrared wavelengths were analyzed to evaluate optical and transport properties of the investigated hydrogen sample and window. Different models of hydrogen EOS were used for one-dimensional hydrodynamic simulation of compression process and estimation of hydrogen temperature within compressed layer. The obtained data demonstrate abrupt change of final temperatures after heating higher then 3500K. Supported by program of Presidium RAS ``Investigation of matter under extreme conditions''

  3. Development of High Temperature Gas Sensor Technology

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; Chen, Liang-Yu; Neudeck, Philip G.; Knight, Dak; Liu, Chung-Chiun; Wu, Quing-Hai; Zhou, Huan-Jun

    1997-01-01

    The measurement of engine emissions is important for their monitoring and control. However, the ability to measure these emissions in-situ is limited. We are developing a family of high temperature gas sensors which are intended to operate in harsh environments such as those in an engine. The development of these sensors is based on progress in two types of technology: (1) The development of SiC-based semiconductor technology; and (2) Improvements in micromachining and microfabrication technology. These technologies are being used to develop point-contact sensors to measure gases which are important in emission control especially hydrogen, hydrocarbons, nitrogen oxides, and oxygen. The purpose of this paper is to discuss the development of this point-contact sensor technology. The detection of each type of gas involves its own challenges in the fields of materials science and fabrication technology. Of particular importance is sensor sensitivity, selectivity, and stability in long-term, high temperature operation. An overview is presented of each sensor type with an evaluation of its stage of development. It is concluded that this technology has significant potential for use in engine applications but further development is necessary.

  4. High temperature size selective membranes

    SciTech Connect

    Yates, S.F.; Swamikannu, A.X.

    1993-09-01

    The high temperature membrane, capable of operation above 550{degree}C, is designed to be a composite membrane composed of a thin layer of a size selective membrane supported by a microporous ceramic support. The kinetic diameters of H{sub 2} and CO{sub 2} are 2.96 {Angstrom} and 4.00 {Angstrom}. The thin layer will be made from CMS whose pore size will be controlled to be less than 4 {Angstrom}. The membrane will be truly size selective and be impermeable to carbon dioxide. The membrane will have higher selectivity than membranes which operate on Knudsen diffusion mechanism. The ceramic support will be fabricated from Allied Signal`s proprietary Blackglas{trademark} resin. The ceramic material, noted for its high thermal and oxidative resistance, has a coefficient of thermal expansion which matches closely that of CMS. The close match will insure mechanical integrity when the membrane is subjected to thermal cycles. The CMS layer will be produced by controlled pyrolysis of polymeric precursors. Pore size will be suitably modified by post-treatments to the carbon. The composite membrane will be tested for its permeation properties at 550{degree}C or higher. Thermal, mechanical and chemical stability of the membrane will be assessed. We have produced several samples of CMS from polymeric precursors. We have initiated work also on the preparation of microporous supports from Blackglas{trademark} resin. We have completed the design of the high temperature membrane pilot plant. The membrane cell was fabricated out of two kinds of stainless steel. The inner parts are made of SS 316 and the outer ring made of SS 420. The greater thermal expansion of the SS 316 will help obtain a leak free seal at the operating temperatures.

  5. High temperature drilling MUD stabilizer

    SciTech Connect

    Block, J.

    1985-10-15

    Aqueous drilling fluids containing a hydroxy containing alumina component such as AlO(OH) and a polyvinyl alcohol (PVA) reaction product such as an aldehyde reacted PVA are stabilized for use at temperatures as high as 350/sup 0/ F. (177/sup 0/ C.) by adding stabilizer anions such as sulfate, tartrate and citrate to the resulting drilling fluid. The anions can be added as an acid or in the salt form with sodium and potassium salts being preferred. The salts are preferably added in 0.2 to 10% by weight of the drilling fluid. These stabilized drilling fluids can also be used in seawater.

  6. CONFINEMENT OF HIGH TEMPERATURE PLASMA

    DOEpatents

    Koenig, H.R.

    1963-05-01

    The confinement of a high temperature plasma in a stellarator in which the magnetic confinement has tended to shift the plasma from the center of the curved, U-shaped end loops is described. Magnetic means are provided for counteracting this tendency of the plasma to be shifted away from the center of the end loops, and in one embodiment this magnetic means is a longitudinally extending magnetic field such as is provided by two sets of parallel conductors bent to follow the U-shaped curvature of the end loops and energized oppositely on the inside and outside of this curvature. (AEC)

  7. Passivation of high temperature superconductors

    NASA Technical Reports Server (NTRS)

    Vasquez, Richard P. (Inventor)

    1991-01-01

    The surface of high temperature superconductors such as YBa2Cu3O(7-x) are passivated by reacting the native Y, Ba and Cu metal ions with an anion such as sulfate or oxalate to form a surface film that is impervious to water and has a solubility in water of no more than 10(exp -3) M. The passivating treatment is preferably conducted by immersing the surface in dilute aqueous acid solution since more soluble species dissolve into the solution. The treatment does not degrade the superconducting properties of the bulk material.

  8. High temperature sealed electrochemical cell

    SciTech Connect

    Valentin Chung, Brice Hoani; Burke, Paul J.; Sadoway, Donald R.

    2015-10-06

    A cell for high temperature electrochemical reactions is provided. The cell includes a container, at least a portion of the container acting as a first electrode. An extension tube has a first end and a second end, the extension tube coupled to the container at the second end forming a conduit from the container to said first end. A second electrode is positioned in the container and extends out of the container via the conduit. A seal is positioned proximate the first end of the extension tube, for sealing the cell.

  9. High Temperature Acoustic Liner Technology

    NASA Technical Reports Server (NTRS)

    Parrott, Tony L.; Jones, Michael G.; Posey, Joe W.

    1999-01-01

    This paper describes work currently in progress at Langley on liner concepts that employ structures that may be suitable for broadband exhaust noise attenuation in high speed flow environments and at elevated temperatures characteristic of HSCT applications. Because such liners will need to provide about 10 dB suppression over a 2 to 3 octave frequency range, conventional single-degree-of-freedom resonant structures will not suffice. Bulk absorbers have the needed broadband absorption characteristic; however, at lower frequencies they tend to be inefficient.

  10. Advanced high-temperature batteries

    NASA Technical Reports Server (NTRS)

    Nelson, Paul A.

    1989-01-01

    The promise of very high specific energy and power was not yet achieved for practical battery systems. Some recent approaches are discussed for new approaches to achieving high performance for lithium/DeS2 cells and sodium/metal chloride cells. The main problems for the development of successful LiAl/FeS2 cells were the instability of the FeS2 electrode, which has resulted in rapidly declining capacity, the lack of an internal mechanism for accommodating overcharge of a cell, thus requiring the use of external charge control on each individual cell, and the lack of a suitable current collector for the positive electrode other than expensive molybdenum sheet material. Much progress was made in solving the first two problems. Reduction of the operating temperatures to 400 C by a change in electrolyte composition has increased the expected life to 1000 cycles. Also, a lithium shuttle mechanism was demonstrated for selected electrode compositions that permits sufficient overcharge tolerance to adjust for the normally expected cell-to-cell deviation in coulombic efficiency. Sodium/sulfur batteries and sodium/metal chloride batteries have demonstrated good reliability and long cycle life. For applications where very high power is desired, new electrolyte coinfigurations would be required. Design work was carried out for the sodium/metal chloride battery that demonstrates the feasibility of achieving high specific energy and high power for large battery cells having thin-walled high-surface area electrolytes.

  11. Spectroscopic study of hydrogen rotational, vibrational and translational temperatures in a hollow cathode glow discharge

    NASA Astrophysics Data System (ADS)

    Majstorovic, G. Lj.

    2008-07-01

    Hydrogen hollow cathode glow discharges (HCGD) have been extensively used for study of fundamental discharge processes as well as for wide variety of applications. For instance, recently, this type of discharge was utilized for producing hydrogen by reforming natural gas (da Silva et al. 2006). The translational or gas kinetic temperature in gas discharges is a parameter of utmost importance in the field of plasma chemistry while vibrationally excited neutral hydrogen molecules play significant role in the chemistry of weakly ionized hydrogen plasmas. This is why the modeling of cold, reactive hydrogen plasma includes rotational and vibrational energy of the hydrogen molecule. This is the reason why we study HC discharge parameters like rotational, translational and vibrational temperature. Several diagnostic techniques are developed to determine gas kinetic temperature T_g like coherent anti-stokes Raman scattering (CARS), laser-induced fluorescence (LIF) and optical emission spectroscopy (OES). Here we selected OES. This diagnostic technique provides information about atom, molecule and ion density in excited and ground state, as well as rotational, vibrational, and gas temperature including the excitation temperature of certain group of excited levels. The technique is applied for measurements of the rotational T_rot, vibrational T_vib and determines translational temperatures in a hollow cathode glow discharge in hydrogen. The rotational temperature of excited electron energy levels is determined from the Boltzmann plot of intensities of rotational moleculelar hydrogen lines belonging to Fulcher-alpha diagonal bands. Following procedure described elsewhere (Astashkevich et al. 2006) the temperature of ground state rovibronic levels is evaluated. The constrains of rotational temperature are discussed in detail. The vibrational temperature is also determined, but from the relative intensities of the H_2 Fulcher-alpha diagonal bands. The dependence of these

  12. High Temperature Fluoride Salt Test Loop

    SciTech Connect

    Aaron, Adam M.; Cunningham, Richard Burns; Fugate, David L.; Holcomb, David Eugene; Kisner, Roger A.; Peretz, Fred J.; Robb, Kevin R.; Wilson, Dane F.; Yoder, Jr, Graydon L.

    2015-12-01

    Effective high-temperature thermal energy exchange and delivery at temperatures over 600°C has the potential of significant impact by reducing both the capital and operating cost of energy conversion and transport systems. It is one of the key technologies necessary for efficient hydrogen production and could potentially enhance efficiencies of high-temperature solar systems. Today, there are no standard commercially available high-performance heat transfer fluids above 600°C. High pressures associated with water and gaseous coolants (such as helium) at elevated temperatures impose limiting design conditions for the materials in most energy systems. Liquid salts offer high-temperature capabilities at low vapor pressures, good heat transport properties, and reasonable costs and are therefore leading candidate fluids for next-generation energy production. Liquid-fluoride-salt-cooled, graphite-moderated reactors, referred to as Fluoride Salt Reactors (FHRs), are specifically designed to exploit the excellent heat transfer properties of liquid fluoride salts while maximizing their thermal efficiency and minimizing cost. The FHR s outstanding heat transfer properties, combined with its fully passive safety, make this reactor the most technologically desirable nuclear power reactor class for next-generation energy production. Multiple FHR designs are presently being considered. These range from the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) [1] design originally developed by UC-Berkeley to the Small Advanced High-Temperature Reactor (SmAHTR) and the large scale FHR both being developed at ORNL [2]. The value of high-temperature, molten-salt-cooled reactors is also recognized internationally, and Czechoslovakia, France, India, and China all have salt-cooled reactor development under way. The liquid salt experiment presently being developed uses the PB-AHTR as its focus. One core design of the PB-AHTR features multiple 20 cm diameter, 3.2 m long fuel channels

  13. Low Temperature Regenerators for Zero Boil-Off Liquid Hydrogen Pulse Tube Cryocoolers

    NASA Technical Reports Server (NTRS)

    Salerno, Louis J.; Kashani, Ali; Helvensteijn, Ben; Kittel, Peter; Arnoldm James O. (Technical Monitor)

    2002-01-01

    Recently, a great deal of attention has been focused on zero boil-off (ZBO) propellant storage as a means of minimizing the launch mass required for long-term exploration missions. A key component of ZBO systems is the cooler. Pulse tube coolers offer the advantage of zero moving mass at the cold head, and recent advances in lightweight, high efficiency cooler technology have paved the way for reliable liquid oxygen (LOx) temperature coolers to be developed which are suitable for flight ZBO systems. Liquid hydrogen (LH2) systems, however, are another matter. For ZBO liquid hydrogen systems, cooling powers of 1-5 watts are required at 20 K. The final development from tier for these coolers is to achieve high efficiency and reliability at lower operating temperatures. Most of the life-limiting issues of flight Stirling and pulse tube coolers are associated with contamination, drive mechanisms, and drive electronics. These problems are well in hand in the present generation coolers. The remaining efficiency and reliability issues reside with the low temperature regenerators. This paper will discuss advances to be made in regenerators for pulse tube LH2 ZBO coolers, present some historical background, and discuss recent progress in regenerator technology development using alloys of erbium.

  14. Universal roles of hydrogen in electrochemical performance of graphene: high rate capacity and atomistic origins

    NASA Astrophysics Data System (ADS)

    Ye, Jianchao; Ong, Mitchell T.; Heo, Tae Wook; Campbell, Patrick G.; Worsley, Marcus A.; Liu, Yuanyue; Shin, Swanee J.; Charnvanichborikarn, Supakit; Matthews, Manyalibo J.; Bagge-Hansen, Michael; Lee, Jonathan R. I.; Wood, Brandon C.; Wang, Y. Morris

    2015-11-01

    Atomic hydrogen exists ubiquitously in graphene materials made by chemical methods. Yet determining the effect of hydrogen on the electrochemical performance of graphene remains a significant challenge. Here we report the experimental observations of high rate capacity in hydrogen-treated 3-dimensional (3D) graphene nanofoam electrodes for lithium ion batteries. Structural and electronic characterization suggests that defect sites and hydrogen play synergistic roles in disrupting sp2 graphene to facilitate fast lithium transport and reversible surface binding, as evidenced by the fast charge-transfer kinetics and increased capacitive contribution in hydrogen-treated 3D graphene. In concert with experiments, multiscale calculations reveal that defect complexes in graphene are prerequisite for low-temperature hydrogenation, and that the hydrogenation of defective or functionalized sites at strained domain boundaries plays a beneficial role in improving rate capacity by opening gaps to facilitate easier Li penetration. Additional reversible capacity is provided by enhanced lithium binding near hydrogen-terminated edge sites. These findings provide qualitative insights in helping the design of graphene-based materials for high-power electrodes.

  15. Universal roles of hydrogen in electrochemical performance of graphene: high rate capacity and atomistic origins

    PubMed Central

    Ye, Jianchao; Ong, Mitchell T.; Heo, Tae Wook; Campbell, Patrick G.; Worsley, Marcus A.; Liu, Yuanyue; Shin, Swanee J.; Charnvanichborikarn, Supakit; Matthews, Manyalibo J.; Bagge-Hansen, Michael; Lee, Jonathan R.I.; Wood, Brandon C.; Wang, Y. Morris

    2015-01-01

    Atomic hydrogen exists ubiquitously in graphene materials made by chemical methods. Yet determining the effect of hydrogen on the electrochemical performance of graphene remains a significant challenge. Here we report the experimental observations of high rate capacity in hydrogen-treated 3-dimensional (3D) graphene nanofoam electrodes for lithium ion batteries. Structural and electronic characterization suggests that defect sites and hydrogen play synergistic roles in disrupting sp2 graphene to facilitate fast lithium transport and reversible surface binding, as evidenced by the fast charge-transfer kinetics and increased capacitive contribution in hydrogen-treated 3D graphene. In concert with experiments, multiscale calculations reveal that defect complexes in graphene are prerequisite for low-temperature hydrogenation, and that the hydrogenation of defective or functionalized sites at strained domain boundaries plays a beneficial role in improving rate capacity by opening gaps to facilitate easier Li penetration. Additional reversible capacity is provided by enhanced lithium binding near hydrogen-terminated edge sites. These findings provide qualitative insights in helping the design of graphene-based materials for high-power electrodes. PMID:26536830

  16. Paradoxical roles of hydrogen in electrochemical performance of graphene: High rate capacity and atomistic origins

    SciTech Connect

    Ye, Jianchao C.; Ong, Mitchell T.; Heo, Tae Wook; Campbell, Patrick G.; Worsley, Marcus A.; Liu, Yuanyue Y.; Charnvanichborikarn, Supakit; Matthews, Manyalibo J.; Bagge-Hansen, Michael; Lee, Jonathan R. I.; Wood, Brandon C.; Wang, Y. Morris; Shin, Swanee J.

    2015-11-05

    Atomic hydrogen exists ubiquitously in graphene materials made by chemical methods. Yet determining the effect of hydrogen on the electrochemical performance of graphene remains a significant challenge. Here we report the experimental observations of high rate capacity in hydrogen-treated 3-dimensional (3D) graphene nanofoam electrodes for lithium ion batteries. Structural and electronic characterization suggests that defect sites and hydrogen play synergistic roles in disrupting sp2 graphene to facilitate fast lithium transport and reversible surface binding, as evidenced by the fast charge-transfer kinetics and increased capacitive contribution in hydrogen-treated 3D graphene. In concert with experiments, multiscale calculations reveal that defect complexes in graphene are prerequisite for low-temperature hydrogenation, and that the hydrogenation of defective or functionalized sites at strained domain boundaries plays a beneficial role in improving rate capacity by opening gaps to facilitate easier Li penetration. Additional reversible capacity is provided by enhanced lithium binding near hydrogen-terminated edge sites. Furthermore, these findings provide qualitative insights in helping the design of graphene-based materials for high-power electrodes.

  17. Paradoxical roles of hydrogen in electrochemical performance of graphene: High rate capacity and atomistic origins

    DOE PAGESBeta

    Ye, Jianchao C.; Ong, Mitchell T.; Heo, Tae Wook; Campbell, Patrick G.; Worsley, Marcus A.; Liu, Yuanyue Y.; Charnvanichborikarn, Supakit; Matthews, Manyalibo J.; Bagge-Hansen, Michael; Lee, Jonathan R. I.; et al

    2015-11-05

    Atomic hydrogen exists ubiquitously in graphene materials made by chemical methods. Yet determining the effect of hydrogen on the electrochemical performance of graphene remains a significant challenge. Here we report the experimental observations of high rate capacity in hydrogen-treated 3-dimensional (3D) graphene nanofoam electrodes for lithium ion batteries. Structural and electronic characterization suggests that defect sites and hydrogen play synergistic roles in disrupting sp2 graphene to facilitate fast lithium transport and reversible surface binding, as evidenced by the fast charge-transfer kinetics and increased capacitive contribution in hydrogen-treated 3D graphene. In concert with experiments, multiscale calculations reveal that defect complexes inmore » graphene are prerequisite for low-temperature hydrogenation, and that the hydrogenation of defective or functionalized sites at strained domain boundaries plays a beneficial role in improving rate capacity by opening gaps to facilitate easier Li penetration. Additional reversible capacity is provided by enhanced lithium binding near hydrogen-terminated edge sites. Furthermore, these findings provide qualitative insights in helping the design of graphene-based materials for high-power electrodes.« less

  18. Rate of the reaction of atomic hydrogen with propyne over an extended pressure and temperature range

    NASA Technical Reports Server (NTRS)

    Whytock, D. A.; Payne, W. A.; Stief, L. J.

    1976-01-01

    The technique of flash photolysis coupled with time resolved detection of H via resonance fluorescence has been used to obtain rate constants for the reaction of atomic hydrogen with propyne at temperatures from 215 to 460 K and at pressures in the range 5-600 torr. The rate constants are strongly pressure dependent and the high pressure limiting values give rise to the Arrhenius expression K = approximately 6 x 10 to the minus 11th exp(-2450T) cu cm per molecule per sec. The results are discussed and compared with those of previous studies

  19. High modulus high temperature glass fibers

    NASA Technical Reports Server (NTRS)

    Bacon, J. F.

    1973-01-01

    The search for a new high-modulus, high-temperature glass fiber involved the preparation of 500 glass compositions lying in 12 glass fields. These systems consisted primarily of low atomic number oxides and rare-earth oxides. Direct optical measurements of the kinetics of crystallization of the cordierite-rare earth system, for example, showed that the addition of rare-earth oxides decreased the rate of formation of cordierite crystals. Glass samples prepared from these systems proved that the rare-earth oxides made large specific contributions to the Young's modulus of the glasses. The best glasses have moduli greater than 21 million psi, the best glass fibers have moduli greater than 18 million psi, and the best glass fiber-epoxy resin composites have tensile strengths of 298,000 psi, compressive strengths of at least 220,000 psi, flexural strengths of 290,000 psi, and short-beam shear strengths of almost 17,000 psi.

  20. Optical high temperature sensor based on fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Zhang, Bowei

    The aim of this thesis is to fabricate a fiber Bragg grating (FBG) temperature sensor that is capable to measure temperatures in excess of 1100°C. For this purpose, two topics have been studied and investigated during this project. One of them is the development of a high temperature resistant molecular-water induced FBGs; and the other is to investigate the effect of microwave-irradiation on the hydrogen-loaded FBG. The molecular-water induced FBGs are different from the other types of FBG. In these devices the refractive index is modulated by the periodic changes of molecular-water concentration within the grating. The device was developed using thermal annealing technology based on hydrogen-load FBG. Thermal stability of these devices was studied by measuring the grating reflectivity from room temperature to 1000°C. The stability of the device was tested by examining the FBG reflectivity for a period of time at certain temperatures. The results show that these devices are extremely stable at temperatures in excess of 1000°C. The hydroxyl concentration in the grating has been also investigated during this thesis. Based on the knowledge of hydroxyl groups inside FBG, a microwave treatment was designed to increase the hydroxyl concentration in the FBG area. The results show that the molecular-water induced grating, which was fabricated using microwave radiated hydrogen-loaded FBI, are stable at temperatures above 1100°C.