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Sample records for high concentration hydrogen

  1. Pd/ZnO nanorods based sensor for highly selective detection of extremely low concentration hydrogen.

    Science.gov (United States)

    Kumar, Mohit; Singh Bhati, Vijendra; Ranwa, Sapana; Singh, Jitendra; Kumar, Mahesh

    2017-03-22

    We report highly hydrogen selective Pd contacted ZnO nanorods based sensor detecting low concentration even at low operating temperature of 50 °C. The sensor performance was investigated for various gases such as H2, CH4, H2S and CO2 at different operating temperatures from 50 °C to 175 °C for various gas concentrations ranging from 7 ppm to 10,000 ppm (1%). The sensor is highly efficient as it detects hydrogen even at low concentration of ~7 ppm and at operating temperature of 50 °C. The sensor's minimum limit of detection and relative response at 175 °C were found 7 ppm with ~38.7% for H2, 110 ppm with ~6.08% for CH4, 500 ppm with ~10.06% for H2S and 1% with ~11.87% for CO2. Here, Pd exhibits dual characteristics as metal contact and excellent catalyst to hydrogen molecules. The activation energy was calculated for all the gases and found lowest ~3.658 kJ/mol for H2. Low activation energy accelerates desorption reactions and enhances the sensor's performance.

  2. Bioconversion of high concentrations of hydrogen sulfide to elemental sulfur in airlift bioreactor.

    Science.gov (United States)

    Zytoon, Mohamed Abdel-Monaem; AlZahrani, Abdulraheem Ahmad; Noweir, Madbuli Hamed; El-Marakby, Fadia Ahmed

    2014-01-01

    Several bioreactor systems are used for biological treatment of hydrogen sulfide. Among these, airlift bioreactors are promising for the bioconversion of hydrogen sulfide into elemental sulfur. The performance of airlift bioreactors is not adequately understood, particularly when directly fed with hydrogen sulfide gas. The objective of this paper is to investigate the performance of an airlift bioreactor fed with high concentrations of H2S with special emphasis on the effect of pH in combination with other factors such as H2S loading rate, oxygen availability, and sulfide accumulation. H2S inlet concentrations between 1,008 ppm and 31,215 ppm were applied and elimination capacities up to 113 g H2S m(-3) h(-1) were achieved in the airlift bioreactor under investigation at a pH range 6.5-8.5. Acidic pH values reduced the elimination capacity. Elemental sulfur recovery up to 95% was achieved under oxygen limited conditions (DO bioreactor tolerated accumulated dissolved sulfide concentrations >500 mg/L at pH values 8.0-8.5, and near 100% removal efficiency was achieved. Overall, the resident microorganisms in the studied airlift bioreactor favored pH values in the alkaline range. The bioreactor performance in terms of elimination capacity and sulfur recovery was better at pH range 8-8.5.

  3. Bioconversion of High Concentrations of Hydrogen Sulfide to Elemental Sulfur in Airlift Bioreactor

    Directory of Open Access Journals (Sweden)

    Mohamed Abdel-Monaem Zytoon

    2014-01-01

    Full Text Available Several bioreactor systems are used for biological treatment of hydrogen sulfide. Among these, airlift bioreactors are promising for the bioconversion of hydrogen sulfide into elemental sulfur. The performance of airlift bioreactors is not adequately understood, particularly when directly fed with hydrogen sulfide gas. The objective of this paper is to investigate the performance of an airlift bioreactor fed with high concentrations of H2S with special emphasis on the effect of pH in combination with other factors such as H2S loading rate, oxygen availability, and sulfide accumulation. H2S inlet concentrations between 1,008 ppm and 31,215 ppm were applied and elimination capacities up to 113 g H2S m−3 h−1 were achieved in the airlift bioreactor under investigation at a pH range 6.5–8.5. Acidic pH values reduced the elimination capacity. Elemental sulfur recovery up to 95% was achieved under oxygen limited conditions (DO 500 mg/L at pH values 8.0–8.5, and near 100% removal efficiency was achieved. Overall, the resident microorganisms in the studied airlift bioreactor favored pH values in the alkaline range. The bioreactor performance in terms of elimination capacity and sulfur recovery was better at pH range 8–8.5.

  4. Conformational Analysis of Proteins in Highly Concentrated Solutions by Dialysis-Coupled Hydrogen/Deuterium Exchange Mass Spectrometry

    DEFF Research Database (Denmark)

    Houde, Damian; Esmail Nazari, Zeinab; Bou-Assaf, George M

    2016-01-01

    When highly concentrated, an antibody solution can exhibit unusual behaviors, which can lead to unwanted properties, such as increased levels of protein aggregation and unusually high viscosity. Molecular modeling, along with many indirect biophysical measurements, has suggested that the cause...... for these phenomena can be due to short range electrostatic and/or hydrophobic protein-protein interactions. Hydrogen/deuterium exchange mass spectrometry (HDX-MS) is a useful tool for investigating protein conformation, dynamics, and interactions. However, "traditional" continuous dilution labeling HDX......-MS experiments have limited utility for the direct analysis of solutions with high concentrations of protein. Here, we present a dialysis-based HDX-MS (di-HDX-MS) method as an alternative HDX-MS labeling format, which takes advantage of passive dialysis rather than the classic dilution workflow. We applied...

  5. Diffusion of Hydrogen in Proton Implanted Silicon: Dependence on the Hydrogen Concentration

    CERN Document Server

    Faccinelli, Martin; Jelinek, Moriz; Wuebben, Thomas; Laven, Johannes G; Schulze, Hans-Joachim; Hadley, Peter

    2016-01-01

    The reported diffusion constants for hydrogen in silicon vary over six orders of magnitude. This spread in measured values is caused by the different concentrations of defects in the silicon that has been studied. Hydrogen diffusion is slowed down as it interacts with impurities. By changing the material properties such as the crystallinity, doping type and impurity concentrations, the diffusivity of hydrogen can be changed by several orders of magnitude. In this study the influence of the hydrogen concentration on the temperature dependence of the diffusion in high energy proton implanted silicon is investigated. We show that the Arrhenius parameters, which describe this temperature dependence decrease with increasing hydrogen concentration. We propose a model where the relevant defects that mediate hydrogen diffusion become saturated with hydrogen at high concentrations. When the defects that provide hydrogen with the lowest energy positions in the lattice are saturated, hydrogen resides at energetically le...

  6. Divacancy-hydrogen complexes in dislocation-free high-purity germanium. [Annealing, Hall effect, steady-state concentration energy dependence

    Energy Technology Data Exchange (ETDEWEB)

    Haller, E.E.; Hubbard, G.S.; Hansen, W.L.; Seeger, A.

    1976-09-01

    A defect center with a single acceptor level at E/sub v/ + 0.08 eV appears in H/sub 2/-grown dislocation-free high-purity germanium. Its concentration changes reversibly upon annealing up to 650 K. By means of Hall-effect and conductivity measurements over a large temperature range the temperature dependence of the steady-state concentration between 450 and 720 K as well as the transients following changes in temperature were determined. The observed acceptor level is attributed to the divacancy-hydrogen complex V/sub 2/H. The complex reacts with hydrogen, dissolved in the Ge lattice or stored in traps, according to V/sub 2/H + H reversible V/sub 2/H/sub 2/. An energy level associated with the divacancy-dihydrogen complex was not observed. These results are in good agreement with the idea that hydrogen in germanium forms a ''very deep donor'' (i.e., the energy level lies inside the valence band).

  7. Suspension Hydrogen Reduction of Iron Oxide Concentrates

    Energy Technology Data Exchange (ETDEWEB)

    H.Y. Sohn

    2008-03-31

    The objective of the project is to develop a new ironmaking technology based on hydrogen and fine iron oxide concentrates in a suspension reduction process. The ultimate objective of the new technology is to replace the blast furnace and to drastically reduce CO2 emissions in the steel industry. The goals of this phase of development are; the performance of detailed material and energy balances, thermochemical and equilibrium calculations for sulfur and phosphorus impurities, the determination of the complete kinetics of hydrogen reduction and bench-scale testing of the suspension reduction process using a large laboratory flash reactor.

  8. Estimation of the hydrogen concentration in rat tissue using an airtight tube following the administration of hydrogen via various routes

    Science.gov (United States)

    Liu, Chi; Kurokawa, Ryosuke; Fujino, Masayuki; Hirano, Shinichi; Sato, Bunpei; Li, Xiao-Kang

    2014-01-01

    Hydrogen exerts beneficial effects in disease animal models of ischemia-reperfusion injury as well as inflammatory and neurological disease. Additionally, molecular hydrogen is useful for various novel medical and therapeutic applications in the clinical setting. In the present study, the hydrogen concentration in rat blood and tissue was estimated. Wistar rats were orally administered hydrogen super-rich water (HSRW), intraperitoneal and intravenous administration of hydrogen super-rich saline (HSRS), and inhalation of hydrogen gas. A new method for determining the hydrogen concentration was then applied using high-quality sensor gas chromatography, after which the specimen was prepared via tissue homogenization in airtight tubes. This method allowed for the sensitive and stable determination of the hydrogen concentration. The hydrogen concentration reached a peak at 5 minutes after oral and intraperitoneal administration, compared to 1 minute after intravenous administration. Following inhalation of hydrogen gas, the hydrogen concentration was found to be significantly increased at 30 minutes and maintained the same level thereafter. These results demonstrate that accurately determining the hydrogen concentration in rat blood and organ tissue is very useful and important for the application of various novel medical and therapeutic therapies using molecular hydrogen. PMID:24975958

  9. An Efficient Pd-Sn Catalyst Supported on MWNTs for Hydrogenation of High Concentrated Acetylene Feedstocks: The Potential Role of Isolated Adsorption Site

    Directory of Open Access Journals (Sweden)

    E. Esmaeili

    2014-04-01

    Full Text Available In the present study, tin-promoted Pd/MWNTs nanocatalystwas synthesized via polyol technique for application in hydrogenation of high-concentrated acetylene feedstocks. TEM images showed a restricted distribution of nanoparticles in the range of 3-5 nm. The results indicated that nanoparticles sizes were resistant to further catalyst deactivation. XRD patterns signified alloying between Pd and Sn which contained a high percentage of ordered intermetallic structures (70.8%, as confirmed by XPS. According to the results, pore blocking and/or fouling was known as the main reasons of the catalyst deactivation. Here, we supposed a novel deactivation mechanism based on which dehydrogenation susceptibility of carbonaceous species (green oil played a significant role in the formation of the isolated adsorption sites and then, catalyst deactivation.

  10. Adsorption process to recover hydrogen from feed gas mixtures having low hydrogen concentration

    Science.gov (United States)

    Golden, Timothy Christopher; Weist, Jr., Edward Landis; Hufton, Jeffrey Raymond; Novosat, Paul Anthony

    2010-04-13

    A process for selectively separating hydrogen from at least one more strongly adsorbable component in a plurality of adsorption beds to produce a hydrogen-rich product gas from a low hydrogen concentration feed with a high recovery rate. Each of the plurality of adsorption beds subjected to a repetitive cycle. The process comprises an adsorption step for producing the hydrogen-rich product from a feed gas mixture comprising 5% to 50% hydrogen, at least two pressure equalization by void space gas withdrawal steps, a provide purge step resulting in a first pressure decrease, a blowdown step resulting in a second pressure decrease, a purge step, at least two pressure equalization by void space gas introduction steps, and a repressurization step. The second pressure decrease is at least 2 times greater than the first pressure decrease.

  11. On critical hydrogen concentration for hydrogen embrittlement of Fe3Al

    Indian Academy of Sciences (India)

    Unknown

    The critical hydrogen concentration for hydrogen embrittlement in iron aluminide, Fe3Al has been estimated (0⋅42 wppm). The estimated critical hydrogen content has been correlated to structural aspects of the decohesion mechanism of hydrogen embrittlement. Keywords. Iron aluminides; hydrogen embrittlement; critical ...

  12. Kinetics of Hydrogen Reduction of Chalcopyrite Concentrate

    Science.gov (United States)

    Chatterjee, Ritayan; Ghosh, Dinabandhu

    2015-12-01

    A Ghatshila chalcopyrite concentrate (average particle size, 50 μm) containing primarily CuFeS2 and SiO2 (Cu 16 pct) was reduced by a stream of hydrogen in a thermogravimetric analyzer (TGA) at selected temperatures [1173 K to 1323 K (900 °C to 1050 °C)], hydrogen flow rates, partial pressures of hydrogen (0.33 × 101.3 to 101.3 kPa), and sample bed heights. The product was a mixture of Cu (26 pct), SiO2, CuFeO2, and Fe. The rate equations for the three typical controlling mechanisms, namely, gas film diffusion (mass transfer), pore diffusion, and interfacial reaction, have been derived for the system geometry under study and applied to identify the rate-controlling steps. The first stage of the reduction, which extended up to the first 13 minutes, was rate controlled by the interfacial reaction. The last stage, which spanned over the last 60 to 120 minutes and accounted for a small percentage of reduction, was controlled by pore diffusion through the built-up Cu (and Fe) layer. The activation energy in the first stage was 101 kJ mol-1 and that in the second stage was 76 kJ mol-1. Subsequent acid leaching with 1 M HCl solution of the reduction product removed all soluble species, leaving a Cu (53.3 pct) + SiO2 mixture, with a small concentration (2.7 pct) of Cu2O in it. This result compares well with the predicted final mixture of Cu (59 pct)-SiO2 based on a mass balance on the starting concentrate. A follow-up heating at 1523 K (1250 °C) produced a sintered Cu-SiO2 composite with spherical copper particles of 400 µm diameter embedded in a silica matrix. Elemental chemical analyses were carried out by energy-dispersive X-ray spectroscopy/atomic absorption spectroscopy. The phase identification and microstructural characterization of Cu-SiO2 mixtures were carried out by X-ray powder diffraction and optical microscopy.

  13. Sensors for Highly Toxic Gases: Methylamine and Hydrogen Chloride Detection at Low Concentrations in an Ionic Liquid on Pt Screen Printed Electrodes

    Directory of Open Access Journals (Sweden)

    Krishnan Murugappan

    2015-10-01

    Full Text Available Commercially available Pt screen printed electrodes (SPEs have been employed as possible electrode materials for methylamine (MA and hydrogen chloride (HCl gas detection. The room temperature ionic liquid (RTIL 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonylimide ([C2mim][NTf2] was used as a solvent and the electrochemical behaviour of both gases was first examined using cyclic voltammetry. The reaction mechanism appears to be the same on Pt SPEs as on Pt microelectrodes. Furthermore, the analytical utility was studied to understand the behaviour of these highly toxic gases at low concentrations on SPEs, with calibration graphs obtained from 10 to 80 ppm. Three different electrochemical techniques were employed: linear sweep voltammetry (LSV, differential pulse voltammetry (DPV and square wave voltammetry (SWV, with no significant differences in the limits of detection (LODs between the techniques (LODs were between 1.4 to 3.6 ppm for all three techniques for both gases. The LODs achieved on Pt SPEs were lower than the current Occupational Safety and Health Administration Permissible Exposure Limit (OSHA PEL limits of the two gases (5 ppm for HCl and 10 ppm for MA, suggesting that Pt SPEs can successfully be combined with RTILs to be used as cheap alternatives for amperometric gas sensing in applications where these toxic gases may be released.

  14. High efficiency stationary hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Hynek, S.; Fuller, W.; Truslow, S. [Arthur D. Little, Inc., Cambridge, MA (United States)

    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.

  15. Effects of ion concentration on the hydrogen bonded structure of ...

    Indian Academy of Sciences (India)

    Molecular dynamics simulations of dilute and concentrated aqueous NaCl solutions are carried out to investigate the changes of the hydrogen bonded structures in the vicinity of ions for different ion concentrations. An analysis of the hydrogen bond population in the first and second solvation shells of the ions and in the bulk ...

  16. Design and assembly of a catalyst bed gas generator for the catalytic decomposition of high concentration hydrogen peroxide propellants and the catalytic combustion of hydrocarbon/air mixtures

    Science.gov (United States)

    Lohner, Kevin A. (Inventor); Mays, Jeffrey A. (Inventor); Sevener, Kathleen M. (Inventor)

    2004-01-01

    A method for designing and assembling a high performance catalyst bed gas generator for use in decomposing propellants, particularly hydrogen peroxide propellants, for use in target, space, and on-orbit propulsion systems and low-emission terrestrial power and gas generation. The gas generator utilizes a sectioned catalyst bed system, and incorporates a robust, high temperature mixed metal oxide catalyst. The gas generator requires no special preheat apparatus or special sequencing to meet start-up requirements, enabling a fast overall response time. The high performance catalyst bed gas generator system has consistently demonstrated high decomposition efficiency, extremely low decomposition roughness, and long operating life on multiple test articles.

  17. 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.

    Science.gov (United States)

    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.

  18. Determination of diffusible and total hydrogen concentration in coated and uncoated steel

    Energy Technology Data Exchange (ETDEWEB)

    Mabho, Nonhlangabezo

    2010-09-23

    The new trend in the steel industry demands thin, flexible, high strength steels with low internal embrittlement. It is a well known fact that the atomic hydrogen which is picked up during production, fabrication and service embrittles the steel. This has led to an extensive research towards the improvement of the quality of metallic materials by focusing on total and diffusible hydrogen concentrations which are responsible for hydrogen embrittlement. Since the internal embrittlement cannot be foreseen, the concentrations of diffusible hydrogen work as indicators while the total hydrogen characterizes the absorbed quantities and quality of that particular product. To meet these requirements, the analytical chemistry methods which include the already existing carrier gas melt (fusion) extraction methods that use infrared and thermal conductivity for total hydrogen detection were applied. The newly constructed carrier gas thermal desorption mass spectroscopy was applied to monitor the diffusible concentration at specific temperatures and desorption rates of hydrogen which will contribute towards the quality of materials during service. The TDMS method also involved the characterization of the energy quantity (activation energy) required by hydrogen to be removed from traps of which irreversible traps are preferred because they enhance the stability of the product by inhibiting the mobility of hydrogen which is detrimental to the metallic structures. The instrumentation for TDMS is quite simple, compact, costs less and applicable to routine analysis. To determine total and diffusible hydrogen, the influence of the following processes: chemical and mechanical zinc coating removal, sample cleaning with organic solvents, conditions for hydrogen absorption by electrolytic hydrogen charging, conditions of hydrogen desorption by storing the sample at room temperature, solid CO{sub 2} and at temperatures of the drier was analysed. The contribution of steel alloys towards

  19. International Conference on Solar Concentrators for the Generation of Electricity or Hydrogen: Book of Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    McConnell, R.; Symko-Davies, M.; Hayden, H.

    2005-05-01

    The International Conference on Solar Concentrators for the Generation of Electricity or Hydrogen provides an opportunity to learn about current significant research on solar concentrators for generating electricity or hydrogen. The conference will emphasize in-depth technical discussions of recent achievements in technologies that convert concentrated solar radiation to electricity or hydrogen, with primary emphasis on photovoltaic (PV) technologies. Very high-efficiency solar cells--above 37%--were recently developed, and are now widely used for powering satellites. This development demands that we take a fresh look at the potential of solar concentrators for generating low-cost electricity or hydrogen. Solar electric concentrators could dramatically overtake other PV technologies in the electric utility marketplace because of the low capital cost of concentrator manufacturing facilities and the larger module size of concentrators. Concentrating solar energy also has advantages for th e solar generation of hydrogen. Around the world, researchers and engineers are developing solar concentrator technologies for entry into the electricity generation market and several have explored the use of concentrators for hydrogen production. The last conference on the subject of solar electric concentrators was held in November of 2003 and proved to be an important opportunity for researchers and developers to share new and crucial information that is helping to stimulate projects in their countries.

  20. Sieving hydrogen based on its high compressibility

    Science.gov (United States)

    Chen, Hangyan; Sun, Deyan; Gong, Xingao; Liu, Zhifeng

    2011-03-01

    Based on carbon nanotube intramolecular junction and a C60, a molecular sieve for hydrogen is presented. The small interspace between C60 and junction provides a size changeable channel for the permselectivity of hydrogen while blocking Ne and Ar. The sieving mechanism is due to the high compressibility of hydrogen.

  1. High temperature inorganic membranes for separating hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Fain, D.E.; Roettger, G.E. [Oak Ridge K-25 Site, TN (United States)

    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.

  2. Dynamic Hydrogen Production from Methanol/Water Photo-Splitting Using Core@Shell-Structured CuS@TiO2 Catalyst Wrapped by High Concentrated TiO2 Particles

    Directory of Open Access Journals (Sweden)

    Younghwan Im

    2013-01-01

    Full Text Available This study focused on the dynamic hydrogen production ability of a core@shell-structured CuS@TiO2 photocatalyst coated with a high concentration of TiO2 particles. The rectangular-shaped CuS particles, 100 nm in length and 60 nm in width, were surrounded by a high concentration of anatase TiO2 particles (>4~5 mol. The synthesized core@shell-structured CuS@TiO2 particles absorbed a long wavelength (a short band gap above 700 nm compared to that pure TiO2, which at approximately 300 nm, leading to easier electronic transitions, even at low energy. Hydrogen evolution from methanol/water photo-splitting over the core@shell-structured CuS@TiO2 photocatalyst increased approximately 10-fold compared to that over pure CuS. In particular, 1.9 mmol of hydrogen gas was produced after 10 hours when 0.5 g of 1CuS@4TiO2 was used at pH = 7. This level of production was increased to more than 4-fold at higher pH. Cyclic voltammetry and UV-visible absorption spectroscopy confirmed that the CuS in CuS@TiO2 strongly withdraws the excited electrons from the valence band in TiO2 because of the higher reduction potential than TiO2, resulting in a slower recombination rate between the electrons and holes and higher photoactivity.

  3. Study on Hydrogen Gas concentration to Voltage and Resistance using Semiconductor Hydrogen Gas Sensor

    Directory of Open Access Journals (Sweden)

    Ahmad Arif Hasibuan

    2016-10-01

    Full Text Available Study on hydrogen gas concentration to changes in voltage and resistance using semiconductor hydrogen gas sensor has been done. The system which has been designed will measure any changes in the voltage and resistance of the sensor automatically when the sensor is given a variation of concentration on hydrogen gas. On the condition of gas with low concentration, the sensor output voltage obtained worth 0:08 Volt and the sensor resistance value of 180 KΩ. On the increase in gas concentration causes an increase in sensor output voltage and a decrease in the value of resistance Studi tentang pengaruh konsentrasi kadar gas hidrogen terhadap perubahan tegangan dan resistansi menggunakan sensor gas hidrogen berbasis semikonduktor telah berhasil dilakukan. Sistem yang telah dirancang akan mengukur setiap perubahan tegangan dan resistansi secara digital pada sensor saat diberikan variasi terhadap konsentrasi kadar gas hidrogen. Pada kondisi gas dengan konsentrasi rendah diperoleh tegangan output sensor senilai 0.08 Volt dan nilai resistansi sensor sebesar 180 KΩ. Pada peningkatan konsentrasi gas menyebabkan peningkatan tegangan output sensor dan sebaliknya terjadi penurunan pada nilai resistansi

  4. 21 CFR 868.1170 - Indwelling blood hydrogen ion concentration (pH) analyzer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Indwelling blood hydrogen ion concentration (pH... Indwelling blood hydrogen ion concentration (pH) analyzer. (a) Identification. An indwelling blood hydrogen ion concentration (pH) analyzer is a device that consists of a catheter-tip pH electrode and that is...

  5. Dynamic nuclear polarization of high-density atomic hydrogen in solid mixtures of molecular hydrogen isotopes.

    Science.gov (United States)

    Sheludiakov, S; Ahokas, J; Järvinen, J; Zvezdov, D; Vainio, O; Lehtonen, L; Vasiliev, S; Mao, S; Khmelenko, V V; Lee, D M

    2014-12-31

    We report on magnetic resonance studies of high-density atomic hydrogen and deuterium in solid hydrogen matrices at temperatures below 1 K. Average concentrations of H atoms ≈3×10(19)  cm(-3) are obtained in chemical tunneling reactions of isotope exchange with D atoms. The products of these reactions are closely located pairs of H atoms near D2 molecules with strong exchange interactions. We discovered a dynamic nuclear polarization effect on H atoms created by pumping the center of the H electron spin resonance spectrum, similar to the Overhauser effect in metals. Our results indicate that H atoms may be arranged inside molecular matrices at separations equivalent to local concentrations of 2.6×10(21)  cm(-3). This opens up a way to build a metallic state of atomic hydrogen at zero pressure.

  6. Practical considerations for measuring hydrogen concentrations in groundwater

    Science.gov (United States)

    Chapelle, F.H.; Vroblesky, D.A.; Woodward, J.C.; Lovley, D.R.

    1997-01-01

    Several practical considerations for measuring concentrations of dissolved molecular hydrogen (H2) in groundwater including 1 sampling methods 2 pumping methods and (3) effects of well casing materials were evaluated. Three different sampling methodologies (a downhole sampler, a gas- stripping method, and a diffusion sampler) were compared. The downhole sampler and gas-stripping methods gave similar results when applied to the same wells, the other hand, appeared to The diffusion sampler, on overestimate H2 concentrations relative to the downhole sampler. Of these methods, the gas-stripping method is better suited to field conditions because it is faster (~ 30 min for a single analysis as opposed to 2 h for the downhole sampler or 8 h for the diffusion sampler), the analysis is easier (less sample manipulation is required), and the data computations are more straightforward (H2 concentrations need not be corrected for water sample volume). Measurement of H2 using the gas-stripping method can be affected by different pumping equipment. Peristaltic, piston, and bladder pumps all gave similar results when applied to water produced from the same well. It was observed, however, that peristaltic-pumped water (which draws water under a negative pressure) enhanced the gas-stripping process and equilibrated slightly faster than either piston or bladder pumps (which push water under a positive pressure). A direct current(dc) electrically driven submersible pump was observed to produce H2 and was not suitable for measuring H2 in groundwater. Measurements from two field sites indicate that iron or steel well casings, produce H2, which masks H2 concentrations in groundwater. PVC-cased wells or wells cased with other materials that do not produce H2 are necessary for measuring H2 concentrations in groundwater.Several practical considerations for measuring concentrations of dissolved molecular hydrogen in groundwater including sampling methods, pumping methods, and effects of

  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

    Science.gov (United States)

    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. Sunlight to hydrogen conversion: Design optimization and energy management of concentrated photovoltaic (CPV-Hydrogen) system using micro genetic algorithm

    KAUST Repository

    Burhan, Muhammad

    2016-02-14

    Owing to the intermittent solar irradiance from cloud cover in the diurnal period and unavailability at night time, the practical design of a solar system requires energy backup storage for an uninterrupted supply or for off-grid operation. However, for highly efficient CPV (concentrated photovoltaic) system, the literature is lacking for energy management and optimization algorithm and tool for standalone operation. In this paper, a system with CPV and electrolyser is presented where beam irradiance of sunlight is harnessed to convert the instantaneously generated electricity into useful Hydrogen/Oxygen gas, where they can be stored and re-used for downstream applications such as the fuel cells, etc. The multi-variable design and multi-objective optimization strategies are proposed and presented for a standalone operation of the CPV-Hydrogen system as well as their system performances, particularly electrical rating of CPV based upon the real weather data of Singapore. © 2016 Elsevier Ltd.

  9. Control Materials of Hydrogen Concentration in Micro Environment and Their Summary of Application

    Directory of Open Access Journals (Sweden)

    Zhu Min

    2018-01-01

    Full Text Available Some materials will be hydrogenated to corrosion, such as metal materials, organic materials, polymer materials and so on, when the concentration of hydrogen in a mixed gas is greater than 4% in a closed space of micro environment. Their performances will be seriously affected. So removing or reducing the concentration of hydrogen in a micro environment can fundamentally solve the problem of hydrogenation corrosion. Metallic hydrogen removing agent and organic hydrogen removing agent are the main research directions of controlling materials of hydrogen concentration in micro environment. Current research status in the world are comprehensively reviewed from these two aspects. Features and application scopes of these two kinds of materials are pointed out separately, which provide a theoretical reference for the prevention of accidents caused by hydrogenation corrosion.

  10. Sodium (Na+) concentration effects on metabolic pathway and estimation of ATP use in dark fermentation hydrogen production through stoichiometric analysis.

    Science.gov (United States)

    Lee, Myoung-Joo; Kim, Tae-Hyeong; Min, Booki; Hwang, Sun-Jin

    2012-10-15

    Batch experiments were conducted to investigate the effects of Na(+) concentration on hydrogen production with dark fermentation. The Na(+) concentration was varied from 0 to 8 g/L in the mixed culture using an anaerobic sludge treated by acid. The maximum hydrogen production was achieved with 1 g-Na(+)/L, whereas the hydrogen production was decreased over 2 g-Na(+)/L due to the inhibitory of Na(+). The mechanisms of Na(+) inhibition to the hydrogen production are studied using pure culture of Clostridium butyricum by calculating the energy balance. At a high sodium concentration, C. butyricum used a greater proportion of the ATP generated via fermentation for cell maintenance rather than for cell synthesis. Additionally, higher Na(+) concentrations shifted the fermentation process toward the acetate synthesis pathway instead of the butyrate pathway, and the value of Y(X/ATP) decreased. With high Na(+) concentrations, a greater ratio of hydrogen was produced via the oxidation of NADH. Excess hydrogen production decreased as the Na(+) concentration increased. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Pt-TiO2/MWCNTs Hybrid Composites for Monitoring Low Hydrogen Concentrations in Air

    Directory of Open Access Journals (Sweden)

    Stefano Trocino

    2012-09-01

    Full Text Available Hydrogen is a valuable fuel for the next energy scenario. Unfortunately, hydrogen is highly flammable at concentrations higher than 4% in air. This aspect makes the monitoring of H2 leaks an essential issue for safety reasons, especially in the transportation field. In this paper, nanocomposites based on Pt-doped TiO2/multiwalled carbon nanotubes (MWCNTs have been introduced as sensitive materials for H2 at low temperatures. Pt-TiO2/MWNTs nanocomposites with different composition have been prepared by a simple wet chemical procedure and their morphological, microstructural and electrical properties were investigated. Resistive thick-film devices have been fabricated printing the hybrid nanocomposites on alumina substrates provided with Pt interdigitated electrodes. Electrical tests in air have shown that embedding MWCNTs in the TiO2 matrix modify markedly the electrical conductivity, providing a means to decrease the resistance of the sensing layer. Pt acts as a catalytic additive. Pt-TiO2/MWNTs-based sensors were found to be sensitive to hydrogen at concentrations between 0.5 and 3% in air, satisfying the requisites for practical applications in hydrogen leak detection devices.

  12. Modelling of hydrogen permeability of membranes for high-purity hydrogen production

    Science.gov (United States)

    Zaika, Yury V.; Rodchenkova, Natalia I.

    2017-11-01

    High-purity hydrogen is required for clean energy and a variety of chemical technology processes. Different alloys, which may be well-suited for use in gas-separation plants, were investigated by measuring specific hydrogen permeability. One had to estimate the parameters of diffusion and sorption to numerically model the different scenarios and experimental conditions of the material usage (including extreme ones), and identify the limiting factors. This paper presents a nonlinear mathematical model taking into account the dynamics of sorption-desorption processes and reversible capture of diffusing hydrogen by inhomogeneity of the material’s structure, and also modification of the model when the transport rate is high. The results of numerical modelling allow to obtain information about output data sensitivity with respect to variations of the material’s hydrogen permeability parameters. Furthermore, it is possible to analyze the dynamics of concentrations and fluxes that cannot be measured directly. Experimental data for Ta77Nb23 and V85Ni15 alloys were used to test the model. This work is supported by the Russian Foundation for Basic Research (Project No. 15-01-00744).

  13. High capacity hydrogen storage nanocomposite materials

    Energy Technology Data Exchange (ETDEWEB)

    Zidan, Ragaiy; Wellons, Matthew S.

    2017-12-12

    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.

  14. High capacity hydrogen storage nanocomposite materials

    Science.gov (United States)

    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.

  15. Molecular dynamics simulations of amorphous hydrogenated carbon under high hydrogen fluxes

    NARCIS (Netherlands)

    de Rooij, E. D.; von Toussaint, U.; Kleyn, A. W.; W. J. Goedheer,

    2009-01-01

    We study the flux dependence of the carbon erosion yield and the hydrogen enrichment of the surface in the high flux regime at 10(28) ions per m(2) s and higher by using molecular dynamics (MD). We simulate an amorphous hydrogenated carbon sample exposed to high flux hydrogen bombardment with a

  16. Advanced high efficiency concentrator cells

    Energy Technology Data Exchange (ETDEWEB)

    Gale, R. (Varian Associates, Inc., Palo Alto, CA (United States). Varian Research Center)

    1992-06-01

    This report describes research to develop the technology needed to demonstrate a monolithic, multijunction, two-terminal, concentrator solar cell with a terrestrial power conversion efficiency greater than 35%. Under three previous subcontracts, Varian developed many of the aspects of a technology needed to fabricate very high efficiency concentrator cells. The current project was aimed at exploiting the new understanding of high efficiency solar cells. Key results covered in this report are as follows. (1) A 1.93-eV AlGaAs/1.42-eV GaAs metal-interconnected cascade cell was manufactured with a one-sun efficiency at 27.6% at air mass 1.5 (AM1.5) global. (2) A 1.0eV InGaAs cell was fabricated on the reverse'' side of a low-doped GaAs substrate with a one-sun efficiency of 2.5% AM1.5 diffuse and a short-circuit current of 14.4 mA/cm{sup 2}. (3) Small-scale manufacturing of GaAs p/n concentrator cells was attempted and obtained an excellent yield of high-efficiency cells. (4) Grown-in tunnel junction cell interconnects that are transparent and thermally stable using C and Si dopants were developed. 10 refs.

  17. A Spectrometric Method for Hydrogen Peroxide Concentration Measurement with a Reusable and Cost-Efficient Sensor

    Directory of Open Access Journals (Sweden)

    Cheng-Chih Hsu

    2015-10-01

    Full Text Available In this study we developed a low cost sensor for measuring the concentration of hydrogen peroxide (H2O2 in liquids utilizing a spectrometric method. The sensor was tested using various concentrations of a peroxidase enzyme immobilized on a glass substrate. H2O2 can be catalyzed by peroxidase and converted into water and oxygen. The reagent 4-amino-phenazone takes up oxygen together with phenol to form a colored product that has absorption peaks at 510 nm and 450 nm. The transmission intensity is strongly related to the hydrogen peroxide concentration, so can be used for quantitative analysis. The measurement range for hydrogen peroxide is from 5 × 10−5% to 1 × 10−3% (0.5 ppm to 10 ppm and the results show high linearity. This device can achieve a sensitivity and resolution of 41,400 (photon count/% and 3.49 × 10−5% (0.35 ppm, respectively. The response time of the sensor is less than 3 min and the sensor can be reused for 10 applications with similar performance.

  18. Measurement of hydrogen peroxide and organic hydroperoxide concentrations during autumn in Beijing, China.

    Science.gov (United States)

    Zhang, Qingyu; Liu, Jiaoyu; He, Youjiang; Yang, Jiaying; Gao, Jian; Liu, Houfeng; Tang, Wei; Chen, Yizhen; Fan, Wenhao; Chen, Xuan; Chai, Fahe; Hatakeyama, Shiro

    2018-02-01

    Gaseous peroxides play important roles in atmospheric chemistry. To understand the pathways of the formation and removal of peroxides, atmospheric peroxide concentrations and their controlling factors were measured from 7:00 to 20:00 in September, October, and November 2013 at a heavily trafficked residential site in Beijing, China, with average concentrations of hydrogen peroxide (H 2 O 2 ) and methyl hydroperoxide (MHP) at 0.55ppb and 0.063ppb, respectively. H 2 O 2 concentrations were higher in the afternoon and lower in the morning and evening, while MHP concentrations did not exhibit a regular diurnal pattern. Both H 2 O 2 and MHP concentrations increased at dusk in most cases. Both peroxides displayed monthly variations with higher concentrations in September. These results suggested that photochemical activity was the main controlling factor on variations of H 2 O 2 concentrations during the measurement period. Increasing concentrations of volatile organic compounds emitted by motor vehicles were important contributors to H 2 O 2 and MHP enrichment. High levels of H 2 O 2 and MHP concentrations which occurred during the measurement period probably resulted from the transport of a polluted air mass with high water vapor content passing over the Bohai Bay, China. Copyright © 2017. Published by Elsevier B.V.

  19. Catalytic polymer membranes for high temperature hydrogenation of viscous liquids

    Energy Technology Data Exchange (ETDEWEB)

    Fritsch, D.; Bengtson, G. [GKSS Research Centre Geesthacht GmbH, Institute of Polymer Research, Max-Planck-Str. 1, 21502 Geesthacht (Germany)

    2006-05-15

    Polymeric membranes with high oil fluxes were developed and catalytically activated by a new route of direct calcination of polymeric membranes charged by Pd or Pt catalyst precursors. High concentrations of citric acid mixed with the precursors afforded a decrease of the calcination temperature to 175 C. Membrane reactor tests in the flow through contactor mode displayed high reactivities for sunflower oil hydrogenation. Pt showed a similar activity to Pd catalysts as measured by iodine value and generated about 13% less trans-isomers but 5% more stearic acid at an iodine value of 90. By means of alumina supported catalysts tests of methyl oleate (cis-C18:1) and methyl elaidate (trans-C18:1) hydrogenation exhibited a different pathway of reaction by either isomerization followed by reduction (Pd) or primarily direct reduction to methyl stearate (Pt). (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  20. Pressure-concentration-temperature characterization of St909 getter alloy with hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Ghezzi, F. [Consiglio Nazionale delle Ricerche, Milan (Italy). Lab. di Fisica del Plasma; Boffito, C. [SAES Getters S.p.A., Milan (Italy)

    1996-06-01

    One of the major issues related to the next generation of fusion reactors is tritium recovery and recycling from tritiated water. Among the various approaches proposed, chemical dissociation of tritiated water over active beds based on reactive alloys appears to be a promising solution. It enables, in fact, safe recovery of tritium by exploiting the relatively high equilibrium pressures, even at low concentrations and operating temperature, of selected alloys. This paper presents the results of pressure-temperature-composition measurements carried out on a Zr-Mn-Fe alloy, named St909, candidate for such an application. Equilibrium isotherms have been determined between room temperature and 400{sup o}C for low hydrogen concentrations, and at room temperature for higher concentrations, exploring the bi-phasic region. Sieverts` law appears to be obeyed in the low concentration range, at H/A ratios of less than 0.03. (Author).

  1. Highly hydrogenated graphene through microwave exfoliation of graphite oxide in hydrogen plasma: towards electrochemical applications.

    Science.gov (United States)

    Eng, Alex Yong Sheng; Sofer, Zdenek; Šimek, Petr; Kosina, Jiri; Pumera, Martin

    2013-11-11

    Hydrogenated graphenes exhibit a variety of properties with potential applications in devices, ranging from a tunable band gap to fluorescence, ferromagnetism, and the storage of hydrogen. We utilize a one-step microwave-irradiation process in hydrogen plasma to create highly hydrogenated graphene from graphite oxides. The procedure serves the dual purposes of deoxygenation and concurrent hydrogenation of the carbon backbone. The effectiveness of the hydrogenation process is investigated on three different graphite oxides (GOs), which are synthesized by using the Staudenmaier, Hofmann, and Hummers methods. A systematic characterization of our hydrogenated graphenes is performed using UV/Vis spectroscopy, SEM, AFM, Raman spectroscopy, FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), combustible elemental analysis, and electrical conductivity measurements. The highest hydrogenation extent is observed in hydrogenated graphene produced from the Hummers-method GO, with a hydrogen content of 19 atomic % in the final product. In terms of the removal of oxygen groups, microwave exfoliation yields graphenes with very similar oxygen contents despite differences in their parent GOs. In addition, we examine the prospective application of hydrogenated graphenes as electrochemical transducers through a cyclic voltammetry (CV) study. The highly hydrogenated graphenes exhibit fast heterogeneous electron-transfer rates, suggestive of their suitability for electrochemical applications in electrodes, supercapacitors, batteries, and sensors. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Solar-hydrogen generation and solar concentration (Conference Presentation)

    NARCIS (Netherlands)

    Sulima, Oleg V.; Chinello, Enrico; Conibeer, Gavin; Modestino, Miquel A.; Schüttauf, Jan-Willem; Lambelet, David; Delfino, Antonio; Domine, Didier; Faes, Antonin; Despeisse, Matthieu; Bailat, Julien; Psaltis, Demetri; Fernandez Rivas, David; Ballif, Christophe; Moser, Christophe

    2016-01-01

    We successfully demonstrated and reported the highest solar-to-hydrogen efficiency with crystalline silicon cells and Earth-abundant electrocatalysts under unconcentrated solar radiation. The combination of hetero-junction silicon cells and a 3D printed Platinum/Iridium-Oxide electrolyzer has been

  3. High yield hydrogen production in a single-chamber membrane-less microbial electrolysis cell.

    Science.gov (United States)

    Ye, Yejie; Wang, Liyong; Chen, Yingwen; Zhu, Shemin; Shen, Shubao

    2010-01-01

    The single-chamber membrane-less MEC exerted much better hydrogen production performance while given higher applied voltages than it did at lower. High applied voltages that could shorten the reaction time and the exposure of anode to air for at least 30 min between cycles can significantly suppress methanogen and increase hydrogen production. At an applied voltage of 1.0 V, a hydrogen production rate of 1.02 m(3)/m(3)/day with a current density of 5.7 A/m(2) was achieved. Cathodic hydrogen recovery and coulombic efficiency were 63.4% and 69.3% respectively. The hydrogen concentration of mixture gas produced of 98.4% was obtained at 1.0 V, which was the best result of reports. The reasons that such a high hydrogen concentration can be achieved were probably the high electrochemical activity and hydrogen production capability of the active microorganisms. Increase in substrate concentrations could not improve MEC's performance, but increased the reaction times. Further, reactor configuration and operation factors optimisation should be considered to increase current density, hydrogen production rate and hydrogen recovery.

  4. Confinement of hydrogen at high pressure in carbon nanotubes

    Science.gov (United States)

    Lassila, David H [Aptos, CA; Bonner, Brian P [Livermore, CA

    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.

  5. Metallic Hydrogen - Potentially a High Energy Rocket Propellant

    Science.gov (United States)

    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.

  6. High Pressure Hydrogen from First Principles

    Science.gov (United States)

    Morales, M. A.

    2014-12-01

    Typical approximations employed in first-principles simulations of high-pressure hydrogen involve the neglect of nuclear quantum effects (NQE) and the approximate treatment of electronic exchange and correlation, typically through a density functional theory (DFT) formulation. In this talk I'll present a detailed analysis of the influence of these approximations on the phase diagram of high-pressure hydrogen, with the goal of identifying the predictive capabilities of current methods and, at the same time, making accurate predictions in this important regime. We use a path integral formulation combined with density functional theory, which allows us to incorporate NQEs in a direct and controllable way. In addition, we use state-of-the-art quantum Monte Carlo calculations to benchmark the accuracy of more approximate mean-field electronic structure calculations based on DFT, and we use GW and hybrid DFT to calculate the optical properties of the solid and liquid phases near metallization. We present accurate predictions of the metal-insulator transition on the solid, including structural and optical properties of the molecular phase. This work was supported by the U.S. Department of Energy at the Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and by LDRD Grant No. 13-LW-004.

  7. Micromechanics of high temperature hydrogen attack

    NARCIS (Netherlands)

    Schlögl, Sabine M.; Giessen, Erik van der

    1999-01-01

    Hydrogen attack is a material degradation process that occurs at elevated temperatures in hydrogen-rich environments, such as found in petro-chemical installations. Weldments in components such as reactor vessels are particularly susceptible to hydrogen attack. This paper discusses a multi-scale

  8. Prediction of hydrogen concentration in containment during severe accidents using fuzzy neural network

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Yeong; Kim, Ju Hyun; Yoo, Kwae Hwan; Na, Man Gyun [Dept. of Nuclear Engineering, Chosun University, Gwangju (Korea, Republic of)

    2015-03-15

    Recently, severe accidents in nuclear power plants (NPPs) have become a global concern. The aim of this paper is to predict the hydrogen buildup within containment resulting from severe accidents. The prediction was based on NPPs of an optimized power reactor 1,000. The increase in the hydrogen concentration in severe accidents is one of the major factors that threaten the integrity of the containment. A method using a fuzzy neural network (FNN) was applied to predict the hydrogen concentration in the containment. The FNN model was developed and verified based on simulation data acquired by simulating MAAP4 code for optimized power reactor 1,000. The FNN model is expected to assist operators to prevent a hydrogen explosion in severe accident situations and manage the accident properly because they are able to predict the changes in the trend of hydrogen concentration at the beginning of real accidents by using the developed FNN model.

  9. High-efficiency solar concentrator

    Science.gov (United States)

    Lansing, F. L.; Dorman, J.

    1980-01-01

    A new type of solar concentrator is presented using liquid lenses and simple translational tracking mechanism. The concentrator achieves a 100:1 nominal concentration ratio and is compared in performance with a flat-plate collector having two sheets of glazing and non-selective coating. The results of the thermal analysis show that higher temperatures can be obtained with the concentrator than is possible with the non-concentrator flat-plate type. Furthermore, the thermal efficiency far exceeds that of the comparative flat-plate type for all operating conditions.

  10. Metallic Membranes for High Temperature Hydrogen Separation

    DEFF Research Database (Denmark)

    Ma, Y.H.; Catalano, Jacopo; Guazzone, Federico

    2013-01-01

    Composite palladium membranes have extensively been studied in laboratories and, more recently, in small pilot industrial applications for the high temperature separation of hydrogen from reactant mixtures such as water-gas shift (WGS) reaction or methane steam reforming (MSR). Composite Pd...... membrane fabrication methods have matured over the last decades, and the deposition of very thin films (1–5 µm) of Pd over porous ceramics or modified porous metal supports is quite common. The H2 permeances and the selectivities achieved at 400–500 °C were in the order of 50–100 Nm3/m/h/bar0.5 and greater...... than 1000, respectively. This chapter describes in detail composite Pd-based membrane preparation methods, which consist of the grading of the support and the deposition of the dense metal layer, their performances, and their applications in catalytic membrane reactors (CMRs) at high temperatures (400...

  11. Structural and spectroscopic ellipsometry characterization for electrodeposited ZnO growth at different hydrogen peroxide concentration

    Energy Technology Data Exchange (ETDEWEB)

    El Hichou, A., E-mail: elhichou@fstg-marrakech.ac.m [Laboratoire de la Matiere Condensee et Nanostructures (LMCN), Faculte des Sciences et Techniques, BP 549, 40000 Marrakech (Morocco); Stein, N.; Boulanger, C. [Institut Jean Lamour, Laboratoire d' Electrochimie des Materiaux, UPV-M, CNRS, 1 bd Arago CP 87811, 57078 Metz cedex 3 (France); Johann, L. [Laboratoire de Physique des Milieux denses, UPV-M, 1 bd Arago CP 87811, 57078 Metz cedex 3 (France)

    2010-05-31

    This work deals with textural and optical characterization of zinc oxide (ZnO) layers obtained by potentiostatic electroplating at various hydrogen peroxide concentrations (from 0 up to 5 mM). The electrodeposition process was studied by cyclic voltametry and chronoamperometry. The [002] preferred growth orientation of hexagonal phase is obtained for the lowest hydrogen peroxide concentration (1 mM), while additionally X-ray diffraction peaks are observed for hydrogen peroxide concentration ranging from 3 to 5 mM. The optical constants and the thickness of films were determined by spectroscopic ellipsometry measurements. The refractive index of all thin films shows normal dispersion behavior. It was also found that refractive index values decrease with increasing hydrogen peroxide concentration. Further, it was revealed that the changes in the optical properties are correlated to the changes in the surface structure.

  12. Low Cost, High Efficiency, High Pressure Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Electrical characteristics and hydrogen concentration of chemical vapor deposited silicon dioxide films: Effect of water treatment

    Science.gov (United States)

    Li, S. C.; Murarka, S. P.

    1992-11-01

    The effect of exposing chemical vapor deposited silicon dioxide directly to water has been investigated. Unlike the effect of the water-related traps in thermally grown silicon dioxide, the capacitance-voltage (C-V) shift due to diffused-in water molecules is directly observed without using the method of avalanche injection. The resonate nuclear reaction technique with 15N ion beam has been used to measure the hydrogen concentration of water-boiled, as-deposited, and rapid thermal-annealed silicon dioxide films. These depth profiles show that the hydrogen-containing species, that are most likely water molecules, diffuse in and out and redistribute in the as-deposited and rapid thermal-annealed films. These hydrogen depth profiles also indicate that the amount of diffused-in water molecules in the oxide is limited by the solubility of the water in the oxide. The solubility of water in the oxide annealed at high temperatures is found to be significantly lower than that in the as-deposited oxide. It is found that diffused-in water molecules, in order to satisfy the water solubility of the oxide, play a compensating role in controlling the oxide charges. Water molecules would continue to diffuse in, and interact with oxide charges and produce charges with reverse polarity that compensate the existing oxide charges until water solubility is satisfied.

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

    Directory of Open Access Journals (Sweden)

    Sangchoel Kim

    2013-10-01

    Full Text Available 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.

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

    Science.gov (United States)

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

    2013-10-09

    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.

  16. Anisotropy of hydrogen diffusion in nickel single crystals: the effects of self-stress and hydrogen concentration on diffusion

    Science.gov (United States)

    Li, J.; Oudriss, A.; Metsue, A.; Bouhattate, J.; Feaugas, X.

    2017-03-01

    Hydrogen diffusion has an important role in solute-dependent hydrogen embrittlement in metals and metallic alloys. In spite of extensive studies, the complexity of hydrogen diffusion in solids remains a phenomenon that needs to be clarified. In this paper, we investigate the anisotropy of hydrogen diffusion in pure nickel single crystals using both an experimental approach and a thermodynamic development. As a first approximation, experimental data from electrochemical permeation and thermal desorption spectroscopy are described using the classical Fick’s laws and an apparent diffusion tensor. Within a thermodynamic framework, the diffusion equation can be derived from Fick’s laws with an apparent diffusion coefficient which contains an added solute content dependent term β. This term is due to the elastic strain field associated with the insertion of solute atoms. For nickel crystals, the dependence of β on the crystallographic orientation arises from the elastic anisotropy. Additionally, our results elucidate the discrepancies between the thermodynamic model and experimental observations of the effect of the solute concentration on the diffusion process. Moreover, this highlights the importance of the impact of hydrogen on vacancy formation and the subsequent consequences on the anisotropy of the apparent diffusion coefficient.

  17. Estimating changes in urban ozone concentrations due to life cycle emissions from hydrogen transportation systems

    Science.gov (United States)

    Wang, Guihua; Ogden, Joan M.; Chang, Daniel P. Y.

    Hydrogen has been proposed as a low polluting alternative transportation fuel that could help improve urban air quality. This paper examines the potential impact of introducing a hydrogen-based transportation system on urban ambient ozone concentrations. This paper considers two scenarios, where significant numbers of new hydrogen vehicles are added to a constant number of gasoline vehicles. In our scenarios hydrogen fuel cell vehicles (HFCVs) are introduced in Sacramento, California at market penetrations of 9% and 20%. From a life cycle analysis (LCA) perspective, considering all the emissions involved in producing, transporting, and using hydrogen, this research compares three hypothetical natural gas to hydrogen pathways: (1) on-site hydrogen production; (2) central hydrogen production with pipeline delivery; and (3) central hydrogen production with liquid hydrogen truck delivery. Using a regression model, this research shows that the daily maximum temperature correlates well with atmospheric ozone formation. However, increases in initial VOC and NO x concentrations do not necessarily increase the peak ozone concentration, and may even cause it to decrease. It is found that ozone formation is generally limited by NO x in the summer and is mostly limited by VOC in the fall in Sacramento. Of the three hydrogen pathways, the truck delivery pathway contributes the most to ozone precursor emissions. Ozone precursor emissions from the truck pathway at 9% market penetration can cause additional 3-h average VOC (or NO x) concentrations up to approximately 0.05% (or 1%) of current pollution levels, and at 20% market penetration up to approximately 0.1% (or 2%) of current pollution levels. However, all of the hydrogen pathways would result in very small (either negative or positive) changes in ozone air quality. In some cases they will result in worse ozone air quality (mostly in July, August, and September), and in some cases they will result in better ozone air quality

  18. Production of JET fuel containing molecules of high hydrogen content

    Directory of Open Access Journals (Sweden)

    Tomasek Sz.

    2017-12-01

    Full Text Available The harmful effects of aviation can only be reduced by using alternative fuels with excellent burning properties and a high hydrogen content in the constituent molecules. Due to increasing plastic consumption the amount of the plastic waste is also higher. Despite the fact that landfill plastic waste has been steadily reduced, the present scenario is not satisfactory. Therefore, the aim of this study is to produce JET fuel containing an alternative component made from straight-run kerosene and the waste polyethylene cracking fraction. We carried out our experiments on a commercial NiMo/Al2O3/P catalyst at the following process parameters: T=200-300°C, P=40 bar, LHSV=1.0-3.0 h-1, hydrogen/hydrocarbon ratio= 400 Nm3/m3. We investigated the effects of the feedstocks and the process parameters on the product yields, the hydrodesulfurization and hydrodearomatization efficiencies, and the main product properties. The liquid product yields varied between 99.7-99.8%. As a result of the hydrogenation the sulfur (1-1780 mg/kg and the aromatic contents (9.0-20.5% of the obtained products and the values of their smoke points (26.0-34.7 mm fulfilled the requirements of JET fuel standard. Additionally, the concentration of paraffins increased in the products and the burning properties were also improved. The freezing points of the products were higher than -47°C, therefore product blending is needed.

  19. Impact of fermentation rate changes on potential hydrogen sulfide concentrations in wine.

    Science.gov (United States)

    Butzke, Christian E; Park, Seung Kook

    2011-05-01

    The correlation between alcoholic fermentation rate, measured as carbon dioxide (CO2) evolution, and the rate of hydrogen sulfide (H2S) formation during wine production was investigated. Both rates and the resulting concentration peaks in fermentor headspace H2S were directly impacted by yeast assimilable nitrogenous compounds in the grape juice. A series of model fermentations was conducted in temperature-controlled and stirred fermentors using a complex model juice with defined concentrations of ammonium ions and/or amino acids. The fermentation rate was measured indirectly by noting the weight loss of the fermentor; H2S was quantitatively trapped in realtime using a pre-calibrated H2S detection tube which was inserted into a fermentor gas relief port. Evolution rates for CO2 and H2S as well as the relative ratios between them were calculated. These fermentations confirmed that total sulfide formation was strongly yeast strain-dependent, and high concentrations of yeast assimilable nitrogen did not necessarily protect against elevated H2S formation. High initial concentrations of ammonium ions via addition of diammonium phosphate (DAP) caused a higher evolution of H2S when compared with a non-supplemented but nondeficient juice. It was observed that the excess availability of a certain yeast assimilable amino acid, arginine, could result in a more sustained CO2 production rate throughout the wine fermentation. The contribution of yeast assimilable amino acids from conventional commercial yeast foods to lowering of the H2S formation was marginal.

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

    Science.gov (United States)

    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.

  1. High-concentration protein formulations: How high is high?

    Science.gov (United States)

    Garidel, Patrick; Kuhn, Alexander B; Schäfer, Lars V; Karow-Zwick, Anne R; Blech, Michaela

    2017-10-01

    High-concentration protein formulation (HCPF) is a term that is used to describe protein formulations, mostly monoclonal antibody (mAb) drugs, at high protein concentration. The concentration is rarely defined, with typical ranges varying between 50 and 150mg/ml for mAbs. The term HCPF is meant to include and express specific solution properties of formulations that are prone to appear at high protein concentrations such as high viscosity, high opalescence, phase separation, gel formation or the increased propensity for protein particle formation. Thus the term HCPF can be understood as a descriptor of protein formulations, usually at high protein (monoclonal antibody) concentrations, which have specific solution, stability and colloidal properties that differ from formulations at low protein concentration (e.g. at 10mg/ml). The current paper highlights in brief the development challenges that might occur for high-concentration protein/monoclonal antibody formulations. In particular, the maximum concentration regimes achievable in HCPF remained unclear. Based on geometrical considerations involving packing of monoclonal antibodies in a lattice we map out a maximum concentration range that might be theoretically achievable. Different geometrical assumptions and packing models are compared and their relevance is critically discussed, in particular concerning the influence of the physicochemical properties of the monoclonal antibodies on their solubility, which is neglected in the simple geometrical model. According to our estimates, monoclonal antibody concentration above 500mg/ml will be very challenging to achieve. Our results have implications for setting up realistic drug product development strategies and for preparing convincing drug target product profiles for development. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. BUBBLE STRIPPING TO DETERMINE HYDROGEN CONCENTRATIONS IN GROUND WATER: A PRACTICAL APPLICATION OF HENRY'S LAW

    Science.gov (United States)

    The Bubble Stripping Method is a chemical testing method that operates on the principle of Henry's Law. It is useful for determining concentrations of hydrogen in well water, and it is capable of detecting concentrations on the order of nanomoles per liter. The method provides ...

  3. Effect of substrate concentration on fermentative hydrogen production from sweet sorghum extract

    DEFF Research Database (Denmark)

    Antonopoulou, G; Gavala, Hariklia N.; Skiadas, Ioannis

    2011-01-01

    The present study focuses on the influence of substrate concentration on the fermentative hydrogen production from the sugars of sweet sorghum extract, in a continuous stirred tank bioreactor. The reactor was operated at a Hydraulic Retention Time of 12 h and substrate concentrations ranging from...

  4. Thermodynamic considerations of arteriovenous gradients of hydrogen ion concentration and carbon dioxide tension.

    Science.gov (United States)

    Rakitzis, E T

    2000-03-01

    It is shown that, in a multicompartmental homeostatic system, the extent of interaction between any two compartments can be assessed by determination of the difference in free energy change of one particular reaction, or a series of coupled reactions, operative in both of the compartments under consideration. Hydrogen ion concentration and carbon dioxide tension have been used to determine free energy change difference relationships between the venous and arterial compartments (-deltadeltaG(a-v)) of the circulatory system. Data from the literature (from two studies of congestive heart failure and one study of experimentally induced cardiac arrest) are used to calculate -deltadeltaG(a-v). It was found that in control subjects -deltadeltaG(a-v) is close to zero, whereas in congestive heart failure or cardiac arrest, the value rises to 150 cal mol(-1) or more, whereas in blood, the approach towards equilibrium between hydrogen and bicarbonate ions and dissolved carbon dioxide (aqueous CO2) is known to be only moderately rapid. It is concluded that, in the system under study, and with respect to the reaction H+ + HCO3- = CO2 + H2O, a high value for the free energy change difference between the two compartments (high -deltadeltaG(a-v)) must be due to an insufficient blood circulation rate. Accordingly, -deltadeltaG(a-v) is probably a quantitative measure of cardiac insufficiency.

  5. High anisotropy of fully hydrogenated borophene

    Science.gov (United States)

    Wang, Zhiqiang; Lü, Tie-Yu; Wang, Hui-Qiong; Feng, Yuan Ping; Zheng, Jin-Cheng

    We have studied the mechanical properties and phonon dispersions of fully hydrogenated borophene (borophane) under strains by first principles calculations. Uniaxial tensile strains along the a- and b-direction, respectively, and biaxial tensile strain have been considered. Our results show that the mechanical properties and phonon stability of borophane are both highly anisotropic. The ultimate tensile strain along the a-direction is only 0.12, but it can be as large as 0.30 along the b-direction. Compared to borophene and other 2D materials (graphene, graphane, silicene, silicane, h-BN, phosphorene and MoS2), borophane presents the most remarkable anisotropy in in-plane ultimate strain, which is very important for strain engineering. Furthermore, the phonon dispersions under the three applied strains indicate that borophane can withstand up to 5% and 15% uniaxial tensile strain along the a- and b-direction, respectively, and 9% biaxial tensile strain, indicating that mechanical failure in borophane is likely to originate from phonon instability.

  6. An experimental study of high-hydrogen welding processes

    Energy Technology Data Exchange (ETDEWEB)

    Fydrych, D.; Labonowski, J.

    2015-07-01

    This paper presents investigation results of determination of the diffusible hydrogen content in deposited metal obtained by means of two most often used methods-the glycerin method and the mercury method. Relation has been defined between results of those methods in the area characteristic of low-hydrogen as well as high-hydrogen welding processes. Relations available in the literature do not include the diffusible hydrogen content in deposited metal greater than 35 ml/100 g. Extending the scope of analysis of the diffusible hydrogen quantity to an 80 ml/100 g level considerably simplifies carrying out the steel weldability assessment with the use of high-hydrogen processes and with welding in water environment. (Author)

  7. A hydrogen-ferric ion rebalance cell operating at low hydrogen concentrations for capacity restoration of iron-chromium redox flow batteries

    Science.gov (United States)

    Zeng, Y. K.; Zhao, T. S.; Zhou, X. L.; Zou, J.; Ren, Y. X.

    2017-06-01

    To eliminate the adverse impacts of hydrogen evolution on the capacity of iron-chromium redox flow batteries (ICRFBs) during the long-term operation and ensure the safe operation of the battery, a rebalance cell that reduces the excessive Fe(III) ions at the positive electrolyte by using the hydrogen evolved from the negative electrolyte is designed, fabricated and tested. The effects of the flow field, hydrogen concentration and H2/N2 mixture gas flow rate on the performance of the hydrogen-ferric ion rebalance cell have been investigated. Results show that: i) an interdigitated flow field based rebalance cell delivers higher limiting current densities than serpentine flow field based one does; ii) the hydrogen utilization can approach 100% at low hydrogen concentrations (≤5%); iii) the apparent exchange current density of hydrogen oxidation reaction in the rebalance cell is proportional to the square root of the hydrogen concentration at the hydrogen concentration from 1.3% to 50%; iv) a continuous rebalance process is demonstrated at the current density of 60 mA cm-2 and hydrogen concentration of 2.5%. Moreover, the cost analysis shows that the rebalance cell is just approximately 1% of an ICRFB system cost.

  8. Multi-Generation Concentrating Solar-Hydrogen Power System for Sustainable Rural Development

    Energy Technology Data Exchange (ETDEWEB)

    Krothapalli, A.; Greska, B.

    2007-07-01

    This paper describes an energy system that is designed to meet the demands of rural populations that currently have no access to grid-connected electricity. Besides electricity, it is well recognized that rural populations need at least a centralized refrigeration system for storage of medicines and other emergency supplies, as well as safe drinking water. Here we propose a district system that will employ a multi-generation concentrated solar power (CSP) system that will generate electricity and supply the heat needed for both absorption refrigeration and membrane distillation (MD) water purification. The electricity will be used to generate hydrogen through highly efficient water electrolysis and individual households can use the hydrogen for generating electricity, via affordable proton exchange membrane (PEM) fuel cells, and as a fuel for cooking. The multi-generation system is being developed such that its components will be easy to manufacture and maintain. As a result, these components will be less efficient than their typical counterparts but their low cost-to-efficiency ratio will allow for us to meet our installation cost goal of $1/Watt for the entire system. The objective of this paper is to introduce the system concept and discuss the system components that are currently under development. (auth)

  9. Long term hydrogen production potential of concentrated photovoltaic (CPV) system in tropical weather of Singapore

    KAUST Repository

    Burhan, Muhammad

    2016-08-23

    Concentrated photovoltaic (CPV) system provides highest solar energy conversion efficiency among all the photovoltaic technologies and provides the most suitable option to convert solar energy into hydrogen, as future sustainable energy carrier. So far, only conventional flat plate PV systems are being used for almost all of the commercial applications. However, most of the studies have only shown the maximum efficiency of hydrogen production using CPV. In actual field conditions, the performance of CPV-Hydrogen system is affected by many parameter and it changes continuously during whole day operation. In this paper, the daily average and long term performances are proposed to analyze the real field potential of the CPV-Hydrogen system, which is of main interest for designers and consumers. An experimental setup is developed and a performance model is proposed to investigate the average and long term production potential of CPV-Hydrogen system. The study is carried out in tropical weather of Singapore. The maximum CPV efficiency of 27-28% and solar to hydrogen (STH) efficiency of 18%, were recorded. In addition, the CPV-Hydrogen system showed the long term average efficiency of 15.5%, for period of one year (12-months), with electrolyser rating of 47 kWh/kg and STH production potential of 218 kWh/kg. Based upon the DNI availability, the system showed hydrogen production potential of 0.153-0.553 kg/m/month, with average production of 0.43 kg/m/month. However, CPV-Hydrogen system has shown annual hydrogen production potential of 5.162 kg/m/year in tropical weather of Singapore.

  10. Ceramic membranes for high temperature hydrogen separation

    Energy Technology Data Exchange (ETDEWEB)

    Fain, D.E.; Roettger, G.E. [Oak Ridge K-25 Site, TN (United States)

    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.

  11. Hydrogen cyanide in ambient air near a gold heap leach field: Measured vs. modeled concentrations

    Science.gov (United States)

    Orloff, Kenneth G.; Kaplan, Brian; Kowalski, Peter

    To extract gold from low-grade ores, a solution of sodium cyanide is trickled over pads of crushed ore. During this operation, small quantities of hydrogen cyanide gas may escape to the ambient air. To assess these emissions, we collected air samples at monitoring stations located on opposite sides of a gold heap leach field at distances ranging from 1100 to 1500 ft from the center of the field. Hydrogen cyanide was detected in 6 of 18 ambient air samples at concentrations ranging from 0.26 to 1.86 parts per billion (ppb). Ambient air samples collected at residential properties located within 2600 ft of the leach field did not contain detectable concentrations of cyanide (detection level of 0.2 ppb). We used site-specific data and two steady-state air dispersion models, ISCST3 and AERMOD, to predict ambient air concentrations of cyanide at the sampling points. The ISCST3 model over-predicted the measured 8-h concentrations of hydrogen cyanide by a factor of 2.4, on average, and the AERMOD model under-predicted the air concentrations of hydrogen cyanide by a factor of 0.76, on average. The major sources of uncertainty in the model predictions were the complex terrain of the area and the uncertainty in the emission rates of cyanide from the leach field. The measured and predicted concentrations of cyanide in the air samples were not at levels that would pose a human health hazard for acute or chronic exposures.

  12. Effect of a Balanced Concentration of Hydrogen on Graphene CVD Growth

    Directory of Open Access Journals (Sweden)

    S. Chaitoglou

    2016-01-01

    Full Text Available The extraordinary properties of graphene make it one of the most interesting materials for future applications. Chemical vapor deposition (CVD is the synthetic method that permits obtaining large areas of monolayer graphene. To achieve this, it is important to find the appropriate conditions for each experimental system. In our CVD reactor working at low pressure, important factors appear to be the pretreatment of the copper substrate, considering both its cleaning and its annealing before the growing process. The carbon precursor/hydrogen flow ratio and its modification during the growth are significant in order to obtain large area graphene crystals with few defects. In this work, we have focused on the study of the methane and the hydrogen flows to control the production of single layer graphene (SLG and its growth time. In particular, we observe that hydrogen concentration increases during a usual growing process (keeping stable the methane/hydrogen flow ratio resulting in etched domains. In order to balance this increase, a modification of the hydrogen flow results in the growth of smooth hexagonal SLG domains. This is a result of the etching effect that hydrogen performs on the growing graphene. It is essential, therefore, to study the moderated presence of hydrogen.

  13. Hydrogen Pressurization of LOX: High Risk/High Reward (Preprint)

    National Research Council Canada - National Science Library

    Turner, Andrew E; Leichner, Aaron

    2006-01-01

    ... filled with hydrogen gas. Airship commercial service, enabled by relatively low-cost hydrogen, died along with the longest vehicle ever to fly, even though thousands of passengers had been transported without incident prior to that time...

  14. Influence of chemical or physical catalysts on high concentration bleaching agents.

    Science.gov (United States)

    Lima, Débora Alves Nunes Leite; Aguiar, Flávio Henrique Baggio; Liporoni, Priscila C Suzy; Munin, Egberto; Ambrosano, Gláucia Maria Bovi; Lovadino, José Roberto

    2011-01-01

    The aim of this in vitro study was to evaluate the bleaching efficacy of high concentration bleaching agents activated by chemical or physical catalysts. This study was divided into two parts. Part 1 evaluated the efficacy of tooth whitening after treatment with 35% hydrogen peroxide (Whiteness HP Maxx) that was activated by different light-curing units: halogen lamp (conventional and bleach mode) (Optilux 501C, Demetron/Kerr), LED first generation (Ultrablue IV, DMC), LED/diode laser (Ultrablue IV, DMC), LED second generation (Bluephase 16i, Ivoclar Vivadent), and no light source (control group). Part 2 provided an analysis of the effect of chemical and physical catalysts on high concentration bleaching agents: 35% hydrogen peroxide (Whiteness HP Maxx) + 20% sodium hydroxide; 35% hydrogen peroxide + 7% sodium bicarbonate; 38% hydrogen peroxide (Opalescence Xtra Boost); 35% hydrogen peroxide + halogen lamp; 35% hydrogen peroxide + 20% sodium hydroxide + halogen lamp; 35% hydrogen peroxide + 7% sodium bicarbonate + halogen lamp; 38% hydrogen peroxide + halogen lamp; and 35% hydrogen peroxide. Blocks obtained from human molars were randomly divided into groups (n = 5) in accordance with bleaching treatments. The efficacy of bleaching was measured using a spectrophotometer. Three bleaching sessions were performed. The results were submitted to ANOVA followed by the Tukey test (5%). For both parts of the study, activated vs. non-activated bleaching did not differ significantly for all sessions tested. Activating systems did not improve the whitening effectiveness of high concentration bleaching agents.

  15. New perspectives on potential hydrogen storage materials using high pressure.

    Science.gov (United States)

    Song, Yang

    2013-09-21

    In addressing the global demand for clean and renewable energy, hydrogen stands out as the most suitable candidate for many fuel applications that require practical and efficient storage of hydrogen. Supplementary to the traditional hydrogen storage methods and materials, the high-pressure technique has emerged as a novel and unique approach to developing new potential hydrogen storage materials. Static compression of materials may result in significant changes in the structures, properties and performance that are important for hydrogen storage applications, and often lead to the formation of unprecedented phases or complexes that have profound implications for hydrogen storage. In this perspective article, 22 types of representative potential hydrogen storage materials that belong to four major classes--simple hydride, complex hydride, chemical hydride and hydrogen containing materials--were reviewed. In particular, their structures, stabilities, and pressure-induced transformations, which were reported in recent experimental works together with supporting theoretical studies, were provided. The important contextual aspects pertinent to hydrogen storage associated with novel structures and transitions were discussed. Finally, the summary of the recent advances reviewed and the insight into the future research in this direction were given.

  16. Materials for the scavanging of hydrogen at high temperatures

    Science.gov (United States)

    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.

  17. Premixer Design for High Hydrogen Fuels

    Energy Technology Data Exchange (ETDEWEB)

    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

  18. EXPERIMENTAL DETERMINATION OF THE HYDROGEN CONCENTRATION IN THE BATTERY BOXES OF THE PASSENGER CARS

    Directory of Open Access Journals (Sweden)

    G. S. Ighnatov

    2010-06-01

    Full Text Available In the work the experimental determination of the hydrogen concentration in accumulator boxes of the coach in a charging mode of nickel-cadmium batteries in operating conditions (stop and operation is presented. The comparison of the obtained characteristics at different environmental and operating conditions as well as the corresponding conclusions are made.

  19. Variation of molecular hydrogen tropospheric concentration over Southern Poland - results of the continuous chromatographic measurements.

    Science.gov (United States)

    Necki, J.; Chmura, L.

    2012-04-01

    Although hydrogen is one of the fundamental constituents of the earth's atmosphere its global balance is still poorly clarified. A few developed inventories diverging values for efficiency of sources and sinks of this gas. The European network for the hydrogen concentrations measurement is based on several unevenly spaced measurement points. While in 2009 MPI Jena has delivered accurate scale for hydrogen measurements and the techniques of analyses are well described, still large areas of Central Europe is uncovered by representative stations. The first measurement point, established under the EUROHYDROS EU program, on the territory of Poland was Kraków city. Different laboratory setups was tested there and compared to each other. The Kraków area has significant car traffic and its geographical location implies frequent temperature inversions in lower troposphere leading to the accumulation of trace gases in atmosphere of the city. Observations launched in 2007 revealed that the concentration of hydrogen fluctuates strongly within diurnal and seasonal timescales. Its average concentration is three times larger than this, observed at the other stations. The European "background" concentrations of hydrogen are not reflected in the Krakow record. An ideal place to carry out observation of the regional air composition for Central Europe is a research station located in the meteorological observatory at Kasprowy Wierch. Measurement point at the top of mountain peak with elevation of 2000m a.s.l. gives an access to the well mixed troposphere. The station delivers also the necessary facilities and logistics. Since year 1996 greenhouse gas measurement program has been operating at this point. The first measurements of atmospheric concentrations of hydrogen at Kasprowy Wierch were performed in year 2010, based on dedicated gas chromatograph using RGD detector installed at the station. Analysis of hydrogen content in the outside air is performed without any enrichment

  20. Fiber performance in hydrogen atmosphere at high temperature

    Science.gov (United States)

    Semjonov, Sergey L.; Kosolapov, Alexey F.; Nikolin, Ivan V.; Ramos, Rogerio; Vaynshteyn, Vladimir; Hartog, Arthur

    2006-04-01

    Optical losses induced in fibers at 300 °C and in hydrogen atmosphere were studied. A non-linear dependence of hydrogen penetration through the carbon coating on hydrogen pressure was observed. It was demonstrated that carbon coating could not defend the fiber from hydrogen penetration for a long time period. At some time, the hydrogen presence in the fiber core resulted in high optical losses in all spectral range in the case of Ge-doped fibers. It was found that the short-wavelength loss edge (SWE) in a Ge-doped fiber co-doped with a small amount of phosphorus was significantly smaller than that in Ge-doped fibers without co-doping. Nevertheless, P-codoping effect did not decrease optical losses related with SWE completely.

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

    Science.gov (United States)

    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.

  2. Effect of Nb on hydrogen-induced delayed fracture in high strength hot stamping steels

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shiqi [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); College of Mechanical Engineering, Yangtze University, Jingzhou 434023 (China); Huang, Yunhua, E-mail: huangyh@mater.ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Sun, Bintang, E-mail: bingtangsun@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Liao, Qingliang [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Lu, Hongzhou [CITIC Metal Co. Ltd., Room 1901, Capital Mansion 6, Xin Yuan Nanlu, Chaoyang District, Beijing 100004 (China); The School of Resources and Environmental Engineering, East China University of Science and Technology, Meilong road 130, Xujiahui District, Shanghai 200237 (China); Jian, Bian [Niobium Tech Asia, 068898 Singapore (Singapore); Mohrbacher, Hardy [NiobelCon bvba, 2970 Schilde (Belgium); Zhang, Wei; Guo, Aimin [CITIC Metal Co. Ltd., Room 1901, Capital Mansion 6, Xin Yuan Nanlu, Chaoyang District, Beijing 100004 (China); Zhang, Yue [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); The State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-02-25

    The effect of Nb addition (0.022, 0.053, 0.078 wt%) on the hydrogen-induced delayed fracture resistance of 22MnB5 was studied by constant load test and electrochemical hydrogen permeation method. It is shown that the appropriate addition of Nb is beneficial to the improvement of the delayed fracture resistance of tested steel, especially when the steel contains high concentration of hydrogen, and the maximum delayed fracture resistance is obtained at a Nb content of 0.053%.The result of hydrogen permeation test shows that the diffusion coefficient of hydrogen in the steel containing niobium is lower than that in steel without niobium, which indicates that it is harder for hydrogen in the steels containing niobium to diffuse and aggregate. In addition, the reason for Nb improving the delayed fracture resistance of steels is discussed from two aspects: hydrogen trap effect and grain refinement effect. The analysis shows that the main reason leading to the improvement of the delayed fracture resistance is the hydrogen trapping effect of NbC while the grain refinement effect of Nb(C,N) secondary.

  3. Electrochemical Hydrogen Storage in a Highly Ordered Mesoporous Carbon

    Directory of Open Access Journals (Sweden)

    Dan eLiu

    2014-10-01

    Full Text Available A highly order mesoporous carbon has been synthesized through a strongly acidic, aqueous cooperative assembly route. The structure and morphology of the carbon material were investigated using TEM, SEM and nitrogen adsorption-desorption isotherms. The carbon was proven to be meso-structural and consisted of graphitic micro-domain with larger interlayer space. AC impedance and electrochemical measurements reveal that the synthesized highly ordered mesoporous carbon exhibits a promoted electrochemical hydrogen insertion process and improved capacitance and hydrogen storage stability. The meso-structure and enlarged interlayer distance within the highly ordered mesoporous carbon are suggested as possible causes for the enhancement in hydrogen storage. Both hydrogen capacity in the carbon and mass diffusion within the matrix were improved.

  4. Micropower chemical fuel-to-electric conversion : a "regenerative flip" hydrogen concentration cell promising near carnot efficiency.

    Energy Technology Data Exchange (ETDEWEB)

    Wally, Karl

    2006-05-01

    Although battery technology is relatively mature, power sources continue to impose serious limitations for small, portable, mobile, or remote applications. A potentially attractive alternative to batteries is chemical fuel-to-electric conversion. Chemical fuels have volumetric energy densities 4 to 10 times those of batteries. However, realizing this advantage requires efficient chemical fuel-to-electric conversion. Direct electrochemical conversion would be the ideal, but, for most fuels, is generally not within the state-of-the-science. Next best, chemical-to-thermal-to-electric conversion can be attractive if efficiencies can be kept high. This small investigative project was an exploration into the feasibility of a novel hybrid (i.e., thermal-electrochemical) micropower converter of high theoretical performance whose demonstration was thought to be within near-term reach. The system is comprised of a hydrogen concentration electrochemical cell with physically identical hydrogen electrodes as anode and cathode, with each electrode connected to physically identical hydride beds each containing the same low-enthalpy-of-formation metal hydride. In operation, electrical power is generated by a hydrogen concentration differential across the electrochemical cell. This differential is established via coordinated heating and passive cooling of the corresponding hydride source and sink. Heating is provided by the exothermic combustion (i.e., either flame combustion or catalytic combustion) of a chemical fuel. Upon hydride source depletion, the role of source and sink are reversed, heating and cooling reversed, electrodes commutatively reversed, cell operation reversed, while power delivery continues unchanged. This 'regenerative flip' of source and sink hydride beds can be cycled continuously until all available heating fuel is consumed. Electricity is efficiently generated electrochemically, but hydrogen is not consumed, rather the hydrogen is regeneratively

  5. Research on High Sensitive D-Shaped FBG Hydrogen Sensors in Power Transformer Oil.

    Science.gov (United States)

    Luo, Ying-Ting; Wang, Hong-Bin; Ma, Guo-Ming; Song, Hong-Tu; Li, Chengrong; Jiang, Jun

    2016-10-04

    Dissolved hydrogen is a symbol gas decomposed by power transformer oil for electrical faults such as overheat or partial discharges. A novel D-shaped fiber Bragg grating (D-FBG) sensor is herein proposed and was fabricated with magnetron sputtering to measure the dissolved hydrogen concentration in power transformer oil in this paper. Different from the RI (refractive index)-based effect, D-FBG in this case is sensitive to curvature caused by stress from sensing coating, leading to Bragg wavelength shifts accordingly. The relationship between the D-FBG wavelength shift and dissolved hydrogen concentration in oil was measured experimentally in the laboratory. The detected sensitivity could be as high as 1.96 μL/L at every 1-pm wavelength shift. The results proved that a simple, polished FBG-based hydrogen sensor provides a linear measuring characteristic in the range of low hydrogen concentrations in transformer oil. Moreover, the stable hydrogen sensing performance was investigated by X-ray diffraction analysis.

  6. Simulation of silicon nanoparticles stabilized by hydrogen at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Galashev, Alexander Y., E-mail: galashev@ecko.uran.r [Russian Academy of Sciences, Ural Division, Institute of Industrial Ecology (Russian Federation)

    2010-10-15

    The stability of different silicon nanoparticles are investigated at a high temperature. The temperature dependence of the physicochemical properties of 60- and 73-atom silicon nanoparticles are investigated using the molecular dynamics method. The 73-atom particles have a crystal structure, a random atomic packing, and a packing formed by inserting a 13-atom icosahedron into a 60-atom fullerene. They are surrounded by a 'coat' from 60 atoms of hydrogen. The nanoassembled particle at the presence of a hydrogen 'coat' has the most stable number (close to four) of Si-Si bonds per atom. The structure and kinetic properties of a hollow single-layer fullerene-structured Si{sub 60} cluster are considered in the temperature range 10 K {<=} T {<=} 1760 K. Five series of calculations are conducted, with a simulation of several media inside and outside the Si{sub 60} cluster, specifically, the vacuum and interior spaces filled with 30 and 60 hydrogen atoms with and without the exterior hydrogen environment of 60 atoms. Fullerene surrounded by a hydrogen 'coat' and containing 60 hydrogen atoms in the interior space has a higher stability. Such cluster has smaller self-diffusion coefficients at high temperatures. The fullerene stabilized with hydrogen is stable to the formation of linear atomic chains up to the temperatures 270-280 K.

  7. A novel tubular microbial electrolysis cell for high rate hydrogen production

    Science.gov (United States)

    Guo, Kun; Prévoteau, Antonin; Rabaey, Korneel

    2017-07-01

    Practical application of microbial electrolysis cells (MECs) for hydrogen production requires scalable reactors with low internal resistance, high current density, and high hydrogen recovery. This work reports a liter scale tubular MEC approaching these requirements. The tubular cell components (a platinum-coated titanium mesh cathode, an anion exchange membrane, and a pleated stainless steel felt anode) were arranged in a concentric configuration. The reactor had a low internal resistance (0.325 Ω, 19.5 mΩ m2) due to the high conductivity of the electrodes, a compact reactor configuration, and proper mixing. With acetate as electron donor, the MEC achieved a volumetric current density of 654 ± 22 mA L-1 (projected current density, 1.09 ± 0.04 mA cm-2) and a volumetric hydrogen production rate of 7.10 ± 0.01 L L-1 d-1 at an applied voltage of 1 V. The reactor also showed high hydrogen recovery (∼100%), high hydrogen purity (>98%), and excellent operational stability during the 3 weeks of operation. These results demonstrated that high hydrogen production rate could be achieved on larger scale MEC and this tubular MEC holds great potential for scaling up.

  8. Effect of substrate concentration on dark fermentation hydrogen production using an anaerobic fluidized bed reactor.

    Science.gov (United States)

    de Amorim, Eduardo Lucena Cavalcante; Sader, Leandro Takano; Silva, Edson Luiz

    2012-03-01

    The effect of substrate (glucose) concentration on the stability and yield of a continuous fermentative process that produces hydrogen was studied. Four anaerobic fluidized bed reactors (AFBRs) were operated with a hydraulic retention time (HRT) from 1 to 8 h and an influent glucose concentration from 2 to 25 g L(-1). The reactors were inoculated with thermally pre-treated anaerobic sludge and operated at a temperature of 30 °C with an influent pH around 5.5 and an effluent pH of about 3.5. The AFBRs with a HRT of 2 h and a feed strength of 2, 4, and 10 g L(-1) showed satisfactory H(2) production performance, but the reactor fed with 25 g L(-1) of glucose did not. The highest hydrogen yield value was obtained in the reactor with a glucose concentration of 2 g L(-1) when it was operated at a HRT of 2 h. The maximum hydrogen production rate value was achieved in the reactor with a HRT of 1 h and a feed strength of 10 g L(-1). The AFBRs operated with glucose concentrations of 2 and 4 g L(-1) produced greater amounts of acetic and butyric acids, while AFBRs with higher glucose concentrations produced a greater amount of solvents.

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

    Science.gov (United States)

    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.

  10. A cohesive zone model to simulate the hydrogen embrittlement effect on a high-strength steel

    Directory of Open Access Journals (Sweden)

    G. Gobbi

    2016-01-01

    Full Text Available The present work aims to model the fracture mechanical behavior of a high-strength low carbon steel, AISI 4130 operating in hydrogen contaminated environment. The study deals with the development of 2D finite element cohesive zone model (CZM reproducing a toughness test. Along the symmetry plane over the crack path of a C(T specimen a zero thickness layer of cohesive elements are implemented in order to simulate the crack propagation. The main feature of this kind of model is the definition of a traction-separation law (TSL that reproduces the constitutive response of the material inside to the cohesive elements. Starting from a TSL calibrated on hydrogen non-contaminated material, the embrittlement effect is simulated by reducing the cohesive energy according to the total hydrogen content including the lattice sites (NILS and the trapped amount. In this perspective, the proposed model consists of three steps of simulations. First step evaluates the hydrostatic pressure. It drives the initial hydrogen concentration assigned in the second step, a mass diffusion analysis, defining in this way the contribution of hydrogen moving across the interstitial lattice sites. The final stress analysis, allows getting the total hydrogen content, including the trapped amount, and evaluating the new crack initiation and propagation due to the hydrogen presence. The model is implemented in both plane strain and plane stress configurations; results are compared in the discussion. From the analyses, it resulted that hydrogen is located only into lattice sites and not in traps, and that the considered steel experiences a high hydrogen susceptibility. By the proposed procedure, the developed numerical model seems a reliable and quick tool able to estimate the mechanical behavior of steels in presence of hydrogen.

  11. HYDROGEN PRODUCTION BY THE CYANOBACTERIUM PLECTONEMA BORYANUM: EFFECTS OF INITIAL NITRATE CONCENTRATION, LIGHT INTENSITY, AND INHIBITION OF PHOTOSYSTEM II BY DCMU

    Energy Technology Data Exchange (ETDEWEB)

    Carter, B.; Huesemann, M.

    2008-01-01

    The alarming rate at which atmospheric carbon dioxide levels are increasing due to the burning of fossil fuels will have incalculable consequences if disregarded. Fuel cells, a source of energy that does not add to carbon dioxide emissions, have become an important topic of study. Although signifi cant advances have been made related to fuel cells, the problem of cheap and renewable hydrogen production still remains. The cyanobacterium Plectonema boryanum has demonstrated potential as a resolution to this problem by producing hydrogen under nitrogen defi cient growing conditions. Plectonema boryanum cultures were tested in a series of experiments to determine the effects of light intensity, initial nitrate concentration, and photosystem II inhibitor DCMU (3-(3,4- dichlorophenyl)-1,1-dimethylurea) upon hydrogen production. Cultures were grown in sterile Chu. No. 10 medium within photobioreactors constantly illuminated by halogen lights. Because the enzyme responsible for hydrogen production is sensitive to oxygen, the medium was continuously sparged with argon/CO2 (99.7%/0.3% vol/vol) by gas dispersion tubes immersed in the culture. Hydrogen production was monitored by using a gas chromatograph equipped with a thermal conductivity detector. In the initial experiment, the effects of initial nitrate concentration were tested and results revealed cumulative hydrogen production was maximum at an initial nitrate concentration of 1 mM. A second experiment was then conducted at an initial nitrate concentration of 1 mM to determine the effects of light intensity at 50, 100, and 200 μmole m-2 s-1. Cumulative hydrogen production increased with increasing light intensity. A fi nal experiment, conducted at an initial nitrate concentration of 2 mM, tested the effects of high light intensity at 200 and 400 μmole m-2 s-1. Excessive light at 400 μmole m-2 s-1 decreased cumulative hydrogen production. Based upon all experiments, cumulative hydrogen production rates were optimal

  12. Prediction of hydrogen concentration in nuclear power plant containment under severe accidents using cascaded fuzzy neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Geon Pil; Kim, Dong Yeong; Yoo, Kwae Hwan; Na, Man Gyun, E-mail: magyna@chosun.ac.kr

    2016-04-15

    Highlights: • We present a hydrogen-concentration prediction method in an NPP containment. • The cascaded fuzzy neural network (CFNN) is used in this prediction model. • The CFNN model is much better than the existing FNN model. • This prediction can help prevent severe accidents in NPP due to hydrogen explosion. - Abstract: Recently, severe accidents in nuclear power plants (NPPs) have attracted worldwide interest since the Fukushima accident. If the hydrogen concentration in an NPP containment is increased above 4% in atmospheric pressure, hydrogen combustion will likely occur. Therefore, the hydrogen concentration must be kept below 4%. This study presents the prediction of hydrogen concentration using cascaded fuzzy neural network (CFNN). The CFNN model repeatedly applies FNN modules that are serially connected. The CFNN model was developed using data on severe accidents in NPPs. The data were obtained by numerically simulating the accident scenarios using the MAAP4 code for optimized power reactor 1000 (OPR1000) because real severe accident data cannot be obtained from actual NPP accidents. The root-mean-square error level predicted by the CFNN model is below approximately 5%. It was confirmed that the CFNN model could accurately predict the hydrogen concentration in the containment. If NPP operators can predict the hydrogen concentration in the containment using the CFNN model, this prediction can assist them in preventing a hydrogen explosion.

  13. Portal venous gas emboli after accidental ingestion of concentrated hydrogen peroxide.

    Science.gov (United States)

    Burns, Rebekah A; Schmidt, Suzanne M

    2013-09-01

    Hydrogen peroxide is a common household product. It is clear and odorless making it easy to confuse with water, especially when improperly stored. Concentrated formulations are also available for consumer purchase. We report a case of hydrogen peroxide ingestion in a child and discuss the potential consequences and treatment of such an exposure. A 12-year-old boy accidentally ingested a sip of concentrated hydrogen peroxide. He rapidly developed hematemesis and presented to the Emergency Department. His initial work-up was unremarkable, and his symptoms resolved quickly. However, diffuse gas emboli were found within the portal system on abdominal computed tomography. The child was treated with hyperbaric oxygen therapy and later found to have gastric irritation as well as an ulcer on endoscopy. He recovered fully from the incident. We present this case to increase awareness of the dangers of hydrogen peroxide ingestion in children. Fortunately, the child in this case recovered fully, but emergency physicians should be aware of the potential consequences and therapeutic options. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Highly hydrogenated graphene via active hydrogen reduction of graphene oxide in the aqueous phase at room temperature.

    Science.gov (United States)

    Sofer, Zdeněk; Jankovský, Ondřej; Šimek, Petr; Soferová, Lýdie; Sedmidubský, David; Pumera, Martin

    2014-02-21

    Hydrogenated graphene and graphane are in the forefront of graphene research. Hydrogenated graphene is expected to exhibit ferromagnetism, tunable band gap, fluorescence, and high thermal and low electrical conductivity. Currently available techniques for fabrication of highly hydrogenated graphene use either a liquid ammonia (-33 °C) reduction pathway using alkali metals or plasma low pressure or ultra high pressure hydrogenation. These methods are either technically challenging or pose inherent risks. Here we wish to demonstrate that highly hydrogenated graphene can be prepared at room temperature in the aqueous phase by reduction of graphene oxide by nascent hydrogen generated by dissolution of metal in acid. Nascent hydrogen is known to be a strong reducing agent. We studied the influence of metal involved in nascent hydrogen generation and characterized the samples in detail. The resulting reduced graphenes and hydrogenated graphenes were characterized in detail. The resulting hydrogenated graphene had the chemical formula C1.16H1O0.66. Such simple hydrogenation of graphene is of high importance for large scale safe synthesis of hydrogenated graphene.

  15. Effect of dissolved hydrogen on corrosion of 316NG stainless steel in high temperature water

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Lijin [Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Road, Shenyang City 110016 (China); Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang City 110819 (China); Peng, Qunjia, E-mail: qunjiapeng@imr.ac.cn [Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Road, Shenyang City 110016 (China); Zhang, Zhiming [Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Road, Shenyang City 110016 (China); Shoji, Tetsuo [Frontier Research Initiative, New Industry Creation Hatchery Center, Tohoku University, 6-6-10, Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Han, En-Hou; Ke, Wei [Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences, 62 Wencui Road, Shenyang City 110016 (China); Wang, Lei [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang City 110819 (China)

    2015-12-15

    Highlights: • Dissolved hydrogen (DH) effect on corrosion of stainless steel in high temperature water. • Increasing DH caused decrease of Cr- but increase of Fe-concentrations in the inner oxide layer. • Concentration gradient of Cr and Fe in the inner oxide layer. • DH effect was attributed to the accelerated diffusion of Fe ion in the inner oxide layer. - Abstract: Characterizations of oxide films formed on 316 stainless steel in high temperature, hydrogenated water were conducted. The results show the oxide film consists of an outer layer with oxide particles of Fe–Ni spinel and hematite, and an inner continuous layer of Fe–Cr–Ni spinel. Increasing dissolved hydrogen (DH) concentrations causes decrease of Cr- and increase of Fe-concentrations in the inner layer. A continuous decrease of Cr- and increase of Fe-concentrations was observed from the surface of the inner layer to the oxide/substrate interface. The DH effect is attributed to the enhanced diffusion of Fe ions in the oxide film by hydrogen.

  16. Hydrogen embrittlement and hydrogen induced stress corrosion cracking of high alloyed austenitic materials; Wasserstoffversproedung und wasserstoffinduzierte Spannungsrisskorrosion hochlegierter austenitischer Werkstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Mummert, K.; Uhlemann, M.; Engelmann, H.J. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany)

    1998-11-01

    The susceptiblity of high alloyed austenitic steels and nickel base alloys to hydrogen-induced cracking is particularly determined by 1. the distribution of hydrogen in the material, and 2. the microstructural deformation behaviour, which last process is determined by the effects of hydrogen with respect to the formation of dislocations and the stacking fault energy. The hydrogen has an influence on the process of slip localization in slip bands, which in turn affects the microstructural deformation behaviour. Slip localization increases with growing Ni contents of the alloys and clearly reduces the ductility of the Ni-base alloy. Although there is a local hydrogen source involved in stress corrosion cracking, emanating from the corrosion process at the cathode, crack growth is observed only in those cases when the hydrogen concentration in a small zone ahead of the crack tip reaches a critical value with respect to the stress conditions. Probability of onset of this process gets lower with growing Ni content of the alloy, due to increasing diffusion velocity of the hydrogen in the austenitic lattice. This is why particularly austenitic steels with low Ni contents are susceptible to transcrystalline stress corrosion cracking. In this case, the microstructural deformation process at the crack tip is also influenced by analogous processes, as could be observed in hydrogen-loaded specimens. (orig./CB) [Deutsch] Die Empfindlichkeit von hochlegierten austentischen Staehlen und Nickelbasislegierungen gegen wasserstoffinduziertes Risswachstum wird im wesentlichen bestimmt durch 1. die Verteilung von Wasserstoff im Werkstoff und 2. das mikrostrukturelle Verformungsverhalten. Das mikrostrukturelle Deformationsverhalten ist wiederum durch den Einfluss von Wasserstoff auf die Versetzungsbildung und die Stapelfehlerenergie charakterisiert. Das mikrostrukturelle Verformungsverhalten wird durch wasserstoffbeeinflusste Gleitlokalisierung in Gleitbaendern bestimmt. Diese nimmt mit

  17. Modeling of the steam hydrolysis in a two-step process for hydrogen production by solar concentrated energy

    Science.gov (United States)

    Valle-Hernández, Julio; Romero-Paredes, Hernando; Pacheco-Reyes, Alejandro

    2017-06-01

    In this paper the simulation of the steam hydrolysis for hydrogen production through the decomposition of cerium oxide is presented. The thermochemical cycle for hydrogen production consists of the endothermic reduction of CeO2 to lower-valence cerium oxide, at high temperature, where concentrated solar energy is used as a source of heat; and of the subsequent steam hydrolysis of the resulting cerium oxide to produce hydrogen. The modeling of endothermic reduction step was presented at the Solar Paces 2015. This work shows the modeling of the exothermic step; the hydrolysis of the cerium oxide (III) to form H2 and the corresponding initial cerium oxide made at lower temperature inside the solar reactor. For this model, three sections of the pipe where the reaction occurs were considered; the steam water inlet, the porous medium and the hydrogen outlet produced. The mathematical model describes the fluid mechanics; mass and energy transfer occurring therein inside the tungsten pipe. Thermochemical process model was simulated in CFD. The results show a temperature distribution in the solar reaction pipe and allow obtaining the fluid dynamics and the heat transfer within the pipe. This work is part of the project "Solar Fuels and Industrial Processes" from the Mexican Center for Innovation in Solar Energy (CEMIE-Sol).

  18. Fabrication of Bulk Glassy Alloy Foams by High Pressure Hydrogen

    Science.gov (United States)

    Wada, Takeshi; Inoue, Akihisa

    Porous Pd42.5Cu30Ni7.5P20 bulk glassy alloy rods with porosities of up to 70% were successfully prepared by high pressure hydrogen of 15 MPa. The melt of Pd42.5Cu30Ni7.5P20 alloy kept under high pressure hydrogen absorbs hydrogen and subsequent water quenching of the melt causes the homogeneous dispersion of hydrogen bubbles, which was resulted from the decrease of hydrogen solubility with decrease of pressure. Annealing the hydrogen bubble containing sample at a supercooled liquid state under vacuum, the bubbles are allowed to expand due to the decrease of viscosity of metallic glass matrix. Pores expansion continues until glassy matrix crystallizes or the equilibration among pressure of the pores, pressure of the atmosphere and surface tension is achieved. By utilizing these phenomena, pores up to 80 m in diameters are homogeneously distributed over the whole cross-sectional area of a fully glassy matrix. Under compressive deformation, the porous alloys with porosities exceeding 40% did not show macroscopic fracture in a wide compressive strain range up to 0.6 whereas the non-porous alloy fractures instantly after elastic limit of about 0.02. Porous bulk glassy alloys exhibit higher plateau stress, lower Young‧s modulus and higher energy absorption capacity compared with the conventional crystalline metal foams.

  19. Hydrogen Assisted Cracking of High Strength Alloys

    National Research Council Canada - National Science Library

    Gangloff, Richard P

    2003-01-01

    ... (Irwin and Wells, 1997; Paris, 1998). Second, materials scientists developed metals with outstanding balances of high tensile strength and high fracture toughness (Garrison, 1990; Wells, 1993; Boyer, 1993...

  20. Determination of hydrogen peroxide concentration using a handheld Raman spectrometer: Detection of an explosives precursor.

    Science.gov (United States)

    Stewart, S P; Bell, S E J; McAuley, D; Baird, I; Speers, S J; Kee, G

    2012-03-10

    It has been shown that a handheld Raman spectrometer can be used to determine hydrogen peroxide concentration in aqueous solutions in seconds. To allow quantitative analysis, the aqueous peroxide samples were mixed 50/50 (v/v) with a 4mol/dm(3) sodium perchlorate solution which acted as the internal standard. Standard calibration using relative peak heights of the strongest perchlorate (932cm(-1)) and peroxide bands (876cm(-1)) gave an average error of 1.43% for samples in the range 5-30% peroxide. PLS regression of the same data set gave an average error of 0.98%. In addition, the concentrations of the samples were estimated by searching spectra against a library of standard spectra prepared using the same range of peroxide concentrations at 5% increments and with the same perchlorate internal standard. It was found that the library searching method classified all the test samples correctly, matching either the spectra of the same concentration, if they were present, or matching to the closest concentration if an exact match was not possible. This method thus provides a very rapid technique to allow determination of hydrogen peroxide concentrations in the field, for example at suspected improvised explosives manufacturing sites, without complex calibration procedures. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  1. Public debate on metallic hydrogen to boost high pressure research

    Directory of Open Access Journals (Sweden)

    Hua Y. Geng

    2017-11-01

    Full Text Available Instead of praises from colleagues, the claim of observation of metallic hydrogen at 495 GPa by Dias and Silvera met much skepticism, and grew into a public debate at the International Conference on High-Pressure Science and Technology, AIRAPT26. We briefly review this debate, and extend the topic to show that this disputation could be an opportunity to benefit the whole high pressure community. Keywords: High pressure, Metallic hydrogen, Quantum solid and liquid, Phase stability, Superconductivity, PACS codes: 61.50.Ks, 67.63.-r, 67.80.-s, 71.30.+h, 74.62.Fj

  2. Considerations for Storage of High Test Hydrogen Peroxide (HTP) Utilizing Non-Metal Containers

    Science.gov (United States)

    Moore, Robin E.; Scott, Joseph P.; Wise, Harry

    2005-01-01

    When working with high concentrations of hydrogen peroxide, it is critical that the storage container be constructed of the proper materials, those which will not degrade to the extent that container breakdown or dangerous decomposition occurs. It has been suggested that the only materials that will safely contain the peroxide for a significant period of time are metals of stainless steel construction or aluminum use as High Test Hydrogen Peroxide (HTP) Containers. The stability and decomposition of HTP will be also discussed as well as various means suggested in the literature to minimize these problems. The dangers of excess oxygen generation are also touched upon.

  3. Ceramic membranes for high temperature hydrogen separation

    Energy Technology Data Exchange (ETDEWEB)

    Adcock, K.D.; Fain, D.E.; James, D.L.; Powell, L.E.; Raj, T.; Roettger, G.E.; Sutton, T.G. [East Tennessee Technology Park, Oak Ridge, TN (United States)

    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.

  4. Cellulase Inhibition by High Concentrations of Monosaccharides

    DEFF Research Database (Denmark)

    Hsieh, Chia-Wen; Cannella, David; Jørgensen, Henning

    2014-01-01

    that low free water availability contributes to cellulase inhibition. Of the hydrolytic enzymes involved, those acting on the cellulose substrate, that is, exo- and endoglucanases, were the most inhibited. The β -glucosidases were shown to be less sensitive to high monosaccharide concentrations except......Biological degradation of biomass on an industrial scale culminates in high concentrations of end products. It is known that the accumulation of glucose and cellobiose, end products of hydrolysis, inhibit cellulases and decrease glucose yields. Aside from these end products, however, other...

  5. Materials for the scavenging of hydrogen at high temperatures

    Science.gov (United States)

    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.

  6. Effect of surface modification, microstructure, and trapping on hydrogen diffusion coefficients in high strength alloys

    Science.gov (United States)

    Jebaraj Johnley Muthuraj, Josiah

    Cathodic protection is widely used for corrosion prevention. However, this process generates hydrogen at the protected metal surface, and diffusion of hydrogen through the metal may cause hydrogen embrittlement or hydrogen induced stress corrosion cracking. Thus the choice of a metal for use as fasteners depends upon its hydrogen uptake, permeation, diffusivity and trapping. The diffusivity of hydrogen through four high strength alloys (AISI 4340, alloy 718, alloy 686, and alloy 59) was analyzed by an electrochemical method developed by Devanathan and Stachurski. The effect of plasma nitriding and microstructure on hydrogen permeation through AISI 4340 was studied on six different specimens: as-received (AR) AISI 4340, nitrided samples with and without compound layer, samples quenched and tempered (Q&T) at 320° and 520°C, and nitrided samples Q&T 520°C. Studies on various nitrided specimens demonstrate that both the gamma'-Fe 4N rich compound surface layer and the deeper N diffusion layer that forms during plasma nitriding reduce the effective hydrogen diffusion coefficient, although the gamma'-Fe4N rich compound layer has a larger effect. Multiple permeation transients yield evidence for the presence of only reversible trap sites in as-received, Q&T 320 and 520 AISI 4340 specimens, and the presence of both reversible and irreversible trap sites in nitrided specimens. Moreover, the changes in microstructure during the quenching and tempering process result in a significant decrease in the diffusion coefficient of hydrogen compared to as-received specimens. In addition, density functional theory-based molecular dynamics simulations yield hydrogen diffusion coefficients through gamma'- Fe4N one order of magnitude lower than through α-Fe, which supports the experimental measurements of hydrogen permeation. The effect of microstructure and trapping was also studied in cold rolled, solutionized, and precipitation hardened Inconel 718 foils. The effective hydrogen

  7. Hydrogen Concentration in the Inner-Most Container within a Pencil Tank Overpack Packaged in a Standard Waste Box Package

    Energy Technology Data Exchange (ETDEWEB)

    Marusich, Robert M.

    2013-08-15

    The purpose of this report is to evaluate hydrogen generation within Pencil Tank Overpacks (PTO) in a Standard Waste Box (SWB), to establish plutonium (Pu) limits for PTOs based on hydrogen concentration in the inner-most container and to establish required configurations or validate existing or proposed configurations for PTOs. The methodology and requirements are provided in this report.

  8. High pressure CO hydrogenation over bimetallic Pt-Co catalysts

    DEFF Research Database (Denmark)

    Christensen, Jakob Munkholt; Medford, Andrew James; Studt, Felix

    2014-01-01

    The potential of bimetallic Pt-Co catalysts for production of higher alcohols in high pressure CO hydrogenation has been assessed. Two catalysts (Pt3Co/SiO2 and PtCo/SiO2) were tested, and the existing literature on CO hydrogenation over Pt-Co catalysts was reviewed. It is found that the catalysts...... produce mainly methanol in the Pt-rich composition range andmainly hydrocarbons (and to a modest extent higher alcohols) in the Co-rich composition range. The transition between the two types of behavior occurs in a narrow composition range around a molar Pt:Co ratio of 1:1....

  9. High rates of catalytic hydrogen combustion with air over coated ...

    Indian Academy of Sciences (India)

    BHASKAR DEVU MUKRI

    2017-08-02

    Aug 2, 2017 ... High rates of catalytic hydrogen combustion with air over. Ti0.97Pd0.03O2−δ coated cordierite monolith. BHASKAR DEVU MUKRI. ∗ and M S HEGDE. Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, India. E-mail: bhaskardm@gmail.com. MS received 9 May 2017; ...

  10. Hydrogen Assisted Cracking of High Strength Alloys

    Science.gov (United States)

    2003-08-01

    Speidel reported simple Arrhenius behavior for lower strength Nimonic 105 (ays = 825 MPa) for 0C < T < 1000C (Speidel, 1974). The very high temperature... 115 of 194 L (a) R 250 nm 250 nm L (b) R Figure 43: Matching field emission SEM images of an IG facet in cz~hardened j3-Ti (Beta-C) cracked in aqueous...Thompson, ASM International, Materials Park, OH, 1974, pp. 115 -147. W.W. Gerberich, Y.T. Chen and C. St. John, A short-time diffusion correlation for

  11. Effect of substrate concentration on hydrogen production by photo-fermentation in the pilot-scale baffled bioreactor.

    Science.gov (United States)

    Lu, Chaoyang; Zhang, Zhiping; Zhou, Xuehua; Hu, Jianjun; Ge, Xumeng; Xia, Chenxi; Zhao, Jia; Wang, Yi; Jing, Yanyan; Li, Yameng; Zhang, Quanguo

    2018-01-01

    Effect of substrate concentration on photo-fermentative hydrogen production was studied with a self-designed 4m3 pilot-scale baffled photo-fermentative hydrogen production reactor (BPHR). The relationships between parameters, such as hydrogen production rate (HPR, mol H2/m3/d), hydrogen concentration, pH value, oxidation-reduction potential, biomass concentration (volatile suspended solids, VSS) and reducing sugar concentration, during the photo-fermentative hydrogen production process were investigated. The highest HPR of 202.64±8.83mol/m3/d was achieved in chamber #3 at a substrate concentration of 20g/L. Hydrogen contents were in the range of 42.19±0.94%-49.71±0.27%. HPR increased when organic loading rate was increased from 3.3 to 20g/L/d, then decreased when organic loading rate was further increased to 25g/L/d. A maximum HPR of 148.65±4.19mol/m3/d was obtained when organic loading rate was maintained at 20g/L/d during continuous bio-hydrogen production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. An experimental study of high-hydrogen welding processes

    Directory of Open Access Journals (Sweden)

    Fydrych, Dariusz

    2015-12-01

    Full Text Available This paper presents investigation results of determination of the diffusible hydrogen content in deposited metal obtained by means of two most often used methods-the glycerin method and the mercury method. Relation has been defined between results of those methods in the area characteristic of low-hydrogen as well as high-hydrogen welding processes. Relations available in the literature do not include the diffusible hydrogen content in deposited metal greater than 35 ml/100 g. Extending the scope of analysis of the diffusible hydrogen quantity to an 80 ml/100 g level considerably simplifies carrying out the steel weldability assessment with the use of high-hydrogen processes and with welding in water environment.Este trabajo presenta los resultados de una investigación sobre la determinación del contenido de hidrógeno difusible en el material aportado mediante dos métodos: el de la glicerina (el más utilizado y el del mercurio. El contenido de dicho hidrógeno se ha definido a partir de los resultados de esos métodos en una zona con bajo contenido en hidrógeno, así como procesos de soldadura con alto contenido en hidrógeno. No hay datos disponibles en la literatura para contenidos de hidrógeno difusible en metal depositado mayores de 35 ml/100 g. Ampliando el análisis de la cantidad de dicho hidrógeno hasta los 80 ml/100 g, se simplifica considerablemente la realización de ensayos de soldabilidad del acero en procesos de alto contenido en hidrógeno así como en la soldadura en medio acuoso.

  13. High-dimensional entanglement concentration of twisted photon pairs High-dimensional entanglement concentration

    Science.gov (United States)

    Chen, L. X.; Wu, Q. P.

    2012-10-01

    Recently, Dada et al. reported on the experimental entanglement concentration and violation of generalized Bell inequalities with orbital angular momentum (OAM) [Nat. Phys. 7, 677 (2011)]. Here we demonstrate that the high-dimensional entanglement concentration can be performed in arbitrary OAM subspaces with selectivity. Instead of violating the generalized Bell inequalities, the working principle of present entanglement concentration is visualized by the biphoton OAM Klyshko picture, and its good performance is confirmed and quantified through the experimental Shannon dimensionalities after concentration.

  14. Networks of ultrasmall Pd/Cr bilayer nanowires as high performance hydrogen sensors.

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, X.-Q.; Wang, Y.-L.; Deng, H.; Latimer, M. L.; Xiao, Z.-L.; Pearson, J.; Xu, T.; Wang, H.-H.; Welp, U.; Crabtree, G. W.; Kwok, W.-K. (Center for Nanoscale Materials); ( MSD); (Northern Illinois Univ.); (Illinois Math and Science Academy); (Univ. of Illinois at Chicago)

    2011-01-01

    The newly developed hydrogen sensor, based on a network of ultrasmall pure palladium nanowires sputter-deposited on a filtration membrane, takes advantage of single palladium nanowires' characteristics of high speed and sensitivity while eliminating their nanofabrication obstacles. However, this new type of sensor, like the single palladium nanowires, cannot distinguish hydrogen concentrations above 3%, thus limiting the potential applications of the sensor. This study reports hydrogen sensors based on a network of ultrasmall Cr-buffered Pd (Pd/Cr) nanowires on a filtration membrane. These sensors not only are able to outperform their pure Pd counterparts in speed and durability but also allow hydrogen detection at concentrations up to 100%. The new networks consist of a thin layer of palladium deposited on top of a Cr adhesion layer 1-3 nm thick. Although the Cr layer is insensitive to hydrogen, it enables the formation of a network of continuous Pd/Cr nanowires with thicknesses of the Pd layer as thin as 2 nm. The improved performance of the Pd/Cr sensors can be attributed to the increased surface area to volume ratio and to the confinement-induced suppression of the phase transition from Pd/H solid solution ({alpha}-phase) to Pd hydride ({beta}-phase).

  15. High Electrocatalytic Hydrogen Evolution Activity of an Anomalous Ruthenium Catalyst.

    Science.gov (United States)

    Zheng, Yao; Jiao, Yan; Zhu, Yihan; Li, Lu Hua; Han, Yu; Chen, Ying; Jaroniec, Mietek; Qiao, Shi-Zhang

    2016-12-14

    Hydrogen evolution reaction (HER) is a critical process due to its fundamental role in electrocatalysis. Practically, the development of high-performance electrocatalysts for HER in alkaline media is of great importance for the conversion of renewable energy to hydrogen fuel via photoelectrochemical water splitting. However, both mechanistic exploration and materials development for HER under alkaline conditions are very limited. Precious Pt metal, which still serves as the state-of-the-art catalyst for HER, is unable to guarantee a sustainable hydrogen supply. Here we report an anomalously structured Ru catalyst that shows 2.5 times higher hydrogen generation rate than Pt and is among the most active HER electrocatalysts yet reported in alkaline solutions. The identification of new face-centered cubic crystallographic structure of Ru nanoparticles was investigated by high-resolution transmission electron microscopy imaging, and its formation mechanism was revealed by spectroscopic characterization and theoretical analysis. For the first time, it is found that the Ru nanocatalyst showed a pronounced effect of the crystal structure on the electrocatalytic activity tested under different conditions. The combination of electrochemical reaction rate measurements and density functional theory computation shows that the high activity of anomalous Ru catalyst in alkaline solution originates from its suitable adsorption energies to some key reaction intermediates and reaction kinetics in the HER process.

  16. High Electrocatalytic Hydrogen Evolution Activity of an Anomalous Ruthenium Catalyst

    KAUST Repository

    Zheng, Yao

    2016-11-28

    Hydrogen evolution reaction (HER) is a critical process due to its fundamental role in electrocatalysis. Practically, the development of high-performance electrocatalysts for HER in alkaline media is of great importance for the conversion of renewable energy to hydrogen fuel via photoelectrochemical water splitting. However, both mechanistic exploration and materials development for HER under alkaline conditions are very limited. Precious Pt metal, which still serves as the state-of-the-art catalyst for HER, is unable to guarantee a sustainable hydrogen supply. Here we report an anomalously structured Ru catalyst that shows 2.5 times higher hydrogen generation rate than Pt and is among the most active HER electrocatalysts yet reported in alkaline solutions. The identification of new face-centered cubic crystallographic structure of Ru nanoparticles was investigated by high-resolution transmission electron microscopy imaging, and its formation mechanism was revealed by spectroscopic characterization and theoretical analysis. For the first time, it is found that the Ru nanocatalyst showed a pronounced effect of the crystal structure on the electrocatalytic activity tested under different conditions. The combination of electrochemical reaction rate measurements and density functional theory computation shows that the high activity of anomalous Ru catalyst in alkaline solution originates from its suitable adsorption energies to some key reaction intermediates and reaction kinetics in the HER process.

  17. Hydrogen evolution activity and electrochemical stability of selected transition metal carbides in concentrated phosphoric acid

    DEFF Research Database (Denmark)

    Tomás García, Antonio Luis; Jensen, Jens Oluf; Bjerrum, Niels J.

    2014-01-01

    Alternative catalysts based on carbides of Group 5 (niobium and tantalum) and 6 (chromium, molybdenum and tungsten) metals were prepared as films on the metallic substrates. The electrochemical activities of these carbide electrodes towards the hydrogen evolution reaction (HER) in concentrated...... phosphoric acid were investigated in a temperature range from 80 to 170°C. A significant dependence of the activities on temperature was observed for all five carbide samples. Through the entire temperature range Group 6 metal carbides showed higher activity than that of the Group 5 metal carbides...

  18. Investigation of hydrogen concentration and hardness of ion irradiated organically modified silicate thin films

    Science.gov (United States)

    Qi, Y.; Prenzel, T.; Harriman, T. A.; Wang, Y. Q.; Lucca, D. A.; Williams, D.; Nastasi, M.; Dong, J.; Mehner, A.

    2010-06-01

    A study of the effects of ion irradiation of organically modified silicate thin films on the loss of hydrogen and increase in hardness is presented. NaOH catalyzed SiNa wO xC yH z thin films were synthesized by sol-gel processing from tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) precursors and spin-coated onto Si substrates. After drying at 300 °C, the films were irradiated with 125 keV H + or 250 keV N 2+ at fluences ranging from 1 × 10 14 to 2.5 × 10 16 ions/cm 2. Elastic Recoil Detection (ERD) was used to investigate resulting hydrogen concentration as a function of ion fluence and irradiating species. Nanoindentation was used to measure the hardness of the irradiated films. FT-IR spectroscopy was also used to examine resulting changes in chemical bonding. The resulting hydrogen loss and increase in hardness are compared to similarly processed acid catalyzed silicate thin films.

  19. Lichen Symbiosis: Nature's High Yielding Machines for Induced Hydrogen Production

    Science.gov (United States)

    Papazi, Aikaterini; Kastanaki, Elizabeth; Pirintsos, Stergios; Kotzabasis, Kiriakos

    2015-01-01

    Hydrogen is a promising future energy source. Although the ability of green algae to produce hydrogen has long been recognized (since 1939) and several biotechnological applications have been attempted, the greatest obstacle, being the O2-sensitivity of the hydrogenase enzyme, has not yet been overcome. In the present contribution, 75 years after the first report on algal hydrogen production, taking advantage of a natural mechanism of oxygen balance, we demonstrate high hydrogen yields by lichens. Lichens have been selected as the ideal organisms in nature for hydrogen production, since they consist of a mycobiont and a photobiont in symbiosis. It has been hypothesized that the mycobiont’s and photobiont’s consumption of oxygen (increase of COX and AOX proteins of mitochondrial respiratory pathways and PTOX protein of chrolorespiration) establishes the required anoxic conditions for the activation of the phycobiont’s hydrogenase in a closed system. Our results clearly supported the above hypothesis, showing that lichens have the ability to activate appropriate bioenergetic pathways depending on the specific incubation conditions. Under light conditions, they successfully use the PSII-dependent and the PSII-independent pathways (decrease of D1 protein and parallel increase of PSaA protein) to transfer electrons to hydrogenase, while under dark conditions, lichens use the PFOR enzyme and the dark fermentative pathway to supply electrons to hydrogenase. These advantages of lichen symbiosis in combination with their ability to survive in extreme environments (while in a dry state) constitute them as unique and valuable hydrogen producing natural factories and pave the way for future biotechnological applications. PMID:25826211

  20. Lichen symbiosis: nature's high yielding machines for induced hydrogen production.

    Directory of Open Access Journals (Sweden)

    Aikaterini Papazi

    Full Text Available Hydrogen is a promising future energy source. Although the ability of green algae to produce hydrogen has long been recognized (since 1939 and several biotechnological applications have been attempted, the greatest obstacle, being the O2-sensitivity of the hydrogenase enzyme, has not yet been overcome. In the present contribution, 75 years after the first report on algal hydrogen production, taking advantage of a natural mechanism of oxygen balance, we demonstrate high hydrogen yields by lichens. Lichens have been selected as the ideal organisms in nature for hydrogen production, since they consist of a mycobiont and a photobiont in symbiosis. It has been hypothesized that the mycobiont's and photobiont's consumption of oxygen (increase of COX and AOX proteins of mitochondrial respiratory pathways and PTOX protein of chrolorespiration establishes the required anoxic conditions for the activation of the phycobiont's hydrogenase in a closed system. Our results clearly supported the above hypothesis, showing that lichens have the ability to activate appropriate bioenergetic pathways depending on the specific incubation conditions. Under light conditions, they successfully use the PSII-dependent and the PSII-independent pathways (decrease of D1 protein and parallel increase of PSaA protein to transfer electrons to hydrogenase, while under dark conditions, lichens use the PFOR enzyme and the dark fermentative pathway to supply electrons to hydrogenase. These advantages of lichen symbiosis in combination with their ability to survive in extreme environments (while in a dry state constitute them as unique and valuable hydrogen producing natural factories and pave the way for future biotechnological applications.

  1. HIGH EFFICIENCY GENERATION OF HYDROGEN FUELS USING NUCLEAR POWER

    Energy Technology Data Exchange (ETDEWEB)

    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

  2. High-temperature biotrickling filtration of hydrogen sulphide.

    Science.gov (United States)

    Datta, Indrani; Fulthorpe, Roberta R; Sharma, Shobha; Allen, D Grant

    2007-03-01

    Biofiltration of malodorous reduced sulphur compounds such as hydrogen sulphide has been confined to emissions that are at temperatures below 40 degrees C despite the fact that there are many industrial emissions (e.g. in the pulp and paper industry) at temperatures well above 40 degrees C. This paper describes our study on the successful treatment of hydrogen sulphide gas at temperatures of 40, 50, 60 and 70 degrees C using a microbial community obtained from a hot spring. Three biotrickling filter (BTF) systems were set up in parallel for a continuous run of 9 months to operate at three different temperatures, one of which was always at 40 degrees C as a mesophilic control and the other two were for exploring high-temperature operation up to 70 degrees C. The continuous experiment and a series of batch experiments in glass bottles (250 ml) showed that addition of glucose and monosodium glutamate enhanced thermophilic biofiltration of hydrogen sulphide gas and a removal rate of 40 g m(-3) h(-1) was achieved at 70 degrees C. We suggest that the glucose is acting as a carbon source for the existing microbial community in the BTFs, whereas glutamate is acting as a compatible solute. The use of such organic compounds to enhance biodegradation of hydrogen sulphide, particularly at high temperatures, has not been demonstrated to our knowledge and, hence, has opened up a range of possibilities for applying biofiltration to hot gas effluent.

  3. Phase II Final Project Report SBIR Project: "A High Efficiency PV to Hydrogen Energy System"

    Energy Technology Data Exchange (ETDEWEB)

    Slade, A; Turner, J; Stone, K; McConnell, R

    2008-09-02

    The innovative research conducted for this project contributed greatly to the understanding of generating low-cost hydrogen from solar energy. The project’s research identified two highly leveraging and complementary pathways. The first pathway is to dramatically increase the efficiency of converting sunlight into electricity. Improving solar electric conversion efficiency directly increases hydrogen production. This project produced a world record efficiency for silicon solar cells and contributed to another world record efficiency for a solar concentrator module using multijunction solar cells. The project’s literature review identified a second pathway in which wasted heat from the solar concentration process augments the electrolysis process generating hydrogen. One way to do this is to use a “heat mirror” that reflects the heat-producing infrared and transmits the visible spectrum to the solar cells; this also increases solar cell conversion efficiency. An economic analysis of this concept confirms that, if long-term concentrator photovoltaic (CPV) and solid-oxide electrolyzer cost goals can be achieved, hydrogen will be produced from solar energy cheaper than the cost of gasoline. The potential public benefits from this project are significant. The project has identified a potential energy source for the nation’s future electricity and transportation needs that is entirely “home grown” and carbon free. As CPV enter the nation’s utility markets, the opportunity for this approach to be successful is greatly increased. Amonix strongly recommends further exploration of this project’s findings.

  4. HYDROGEN ADDITION ON COMBUSTION AND EMISSION CHARACTERISTICS OF HIGH SPEED SPARK IGNITION ENGINE- AN EXPERIMENTAL STUDY

    Directory of Open Access Journals (Sweden)

    SHIVAPRASAD K. V.

    2016-11-01

    Full Text Available The present article aims at characterizing the combustion and emission parameters of a single cylinder high speed SI engine operating with different concentrations of hydrogen with gasoline fuel. The conventional carburetted SI engine was modified into an electronically controllable engine, wherein ECU was used to control the injection timings and durations of gasoline. The engine was maintained at a constant speed of 3000 rpm and wide open throttle position. The experimental results demonstrated that heat release rate and cylinder pressure were increased with the addition of hydrogen until 20%. The CO and HC emissions were reduced considerably whereas NOx emission was increased with the addition of hydrogen in comparison with pure gasoline engine operation.

  5. Investigations for optimal dissolved hydrogen (DH) concentration in reactor coolant system (RCS)

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, Nobuaki; Tanaka, Muneo [Shikoku Electric Power Co., Inc., Takamatsu (Japan); Nishizawa, Eiichi; Kasahara, Kazuo

    1998-12-31

    Optimal dissolved hydrogen (DH) concentration control is among the most important issues in developing program to maintain plant reliability for aging plant because it is useful in securing material integrity. Also, it is believed to be one of the most promising approaches, following pH control and Zn injection, to radiation exposure source reduction. This work involved collecting data for corrosion products in the coolant, particularly Ni (because the chemical forms of this element, parent element of {sup 58}Co, are affected by DH concentration), during the power operation at Ikata NPP, and determining the relations between DH, crud chemical forms and particle size distributions. In order to determine the optimal DH concentration for exposure source reduction, the results were evaluated in comparison with the findings about crud chemical forms from thermodynamic methods. Regarding DH dependence of crud characteristics, the results of field investigations revealed as follows: In crud chemical form, the ratio of Ni (metal) to total crud increases as the DH concentration increments. {sup 58}Co (Ni (metal) and spinel combined) median particle size grows greater as the DH concentration increments. These findings, together with other obtained findings (e.g., relations between particle size and release/deposition) and the calculations developed using thermodynamic methods, brought us to the following conclusion over the DH concentration control for the radiation exposure source reduction. Provided that the DH concentration should be controlled within the typical value (25 to 35 cc-STP/kg-H{sub 2}O), that concentration should be as close to the lower limit (25 cc-STP/kg-H{sub 2}O) as possible and the variation of DH concentration should be minimized. (J.P.N.)

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

    Science.gov (United States)

    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.

  7. Synthesis and stability of hydrogen selenide compounds at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Pace, Edward J.; Binns, Jack; Alvarez, Miriam Pena; Dalladay-Simpson, Philip; Gregoryanz, Eugene; Howie, Ross T. (Edinburgh); (CHPSTAR- China)

    2017-11-14

    The observation of high-temperature superconductivity in hydride sulfide (H2S) at high pressures has generated considerable interest in compressed hydrogen-rich compounds. High-pressure hydrogen selenide (H2Se) has also been predicted to be superconducting at high temperatures; however, its behaviour and stability upon compression remains unknown. In this study, we synthesize H2Se in situ from elemental Se and molecular H2 at pressures of 0.4 GPa and temperatures of 473 K. On compression at 300 K, we observe the high-pressure solid phase sequence (I-I'-IV) of H2Se through Raman spectroscopy and x-ray diffraction measurements, before dissociation into its constituent elements. Through the compression of H2Se in H2 media, we also observe the formation of a host-guest structure, (H2Se)2H2, which is stable at the same conditions as H2Se, with respect to decomposition. These measurements show that the behaviour of H2Se is remarkably similar to that of H2S and provides further understanding of the hydrogen chalcogenides under pressure.

  8. Hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Pier, M.

    1943-02-19

    A transcript is presented of a speech on the history of the development of hydrogenation of coal and tar. Apparently the talk had been accompanied by the showing of photographic slides, but none of the pictures were included with the report. In giving the history, Dr. Pier mentioned the dependence of much of the development of hydrogenation upon previous development in the related areas of ammonia and methanol syntheses, but he also pointed out several ways in which equipment appropriate for hydrogenation differed considerably from that used for ammonia and methanol. Dr. Pier discussed the difficulties encountered with residue processing, design of the reaction ovens, manufacture of ovens and preheaters, heating of reaction mixtures, development of steels, and development of compressor pumps. He described in some detail his own involvement in the development of the process. In addition, he discussed the development of methods of testing gasolines and other fuels. Also he listed some important byproducts of hydrogenation, such as phenols and polycyclic aromatics, and he discussed the formation of iso-octane fuel from the butanes arising from hydrogenation. In connection with several kinds of equipment used in hydrogenation (whose pictures were being shown), Dr. Pier gave some of the design and operating data.

  9. Highly condensed aromatics and their connection to hydrogenation asphalts

    Energy Technology Data Exchange (ETDEWEB)

    Boente, L.

    1944-11-22

    An attempt is made to account for the structure of asphalts and resins which arose in residues upon hydrogenation of coal. The main assumption is that most of these asphalts consisted of highly condensed aromatics, which are considered as derivatives of the substance coronene, which could be described as having the structure consisting of six benzene rings arranged around a central seventh benzene ring. Part of the discussion is speculative, but evidence is given which had led to that speculation. The asphalts had been very hard to analyze exactly, partly because of their very low solubility in most solvents and their very high boiling points. Possible mechanisms for the formation of such highly condensed aromatics during the hydrogenation process are described along with experimental work aimed in part at hydrogenating these aromatics and in part at producing them by condensation reactions of aluminum chloride on coronene. Some of the products of the condensation reactions even resembled coke or soot, while others were red substances which fluoresced green in phenanthrene solution. It is hypothesized that coronene could be looked upon as the basic nucleus for a whole series of highly condensed aromatic molecules, in the same way that benzene is looked upon as the basic nucleus for a whole series of aromatic compounds.

  10. Low-Cost High-Pressure Hydrogen Generator

    Energy Technology Data Exchange (ETDEWEB)

    Cropley, Cecelia C.; Norman, Timothy J.

    2008-04-02

    Electrolysis of water, particularly in conjunction with renewable energy sources, is potentially a cost-effective and environmentally friendly method of producing hydrogen at dispersed forecourt sites, such as automotive fueling stations. The primary feedstock for an electrolyzer is electricity, which could be produced by renewable sources such as wind or solar that do not produce carbon dioxide or other greenhouse gas emissions. However, state-of-the-art electrolyzer systems are not economically competitive for forecourt hydrogen production due to their high capital and operating costs, particularly the cost of the electricity used by the electrolyzer stack. In this project, Giner Electrochemical Systems, LLC (GES) developed a low cost, high efficiency proton-exchange membrane (PEM) electrolysis system for hydrogen production at moderate pressure (300 to 400 psig). The electrolyzer stack operates at differential pressure, with hydrogen produced at moderate pressure while oxygen is evolved at near-atmospheric pressure, reducing the cost of the water feed and oxygen handling subsystems. The project included basic research on catalysts and membranes to improve the efficiency of the electrolysis reaction as well as development of advanced materials and component fabrication methods to reduce the capital cost of the electrolyzer stack and system. The project culminated in delivery of a prototype electrolyzer module to the National Renewable Energy Laboratory for testing at the National Wind Technology Center. Electrolysis cell efficiency of 72% (based on the lower heating value of hydrogen) was demonstrated using an advanced high-strength membrane developed in this project. This membrane would enable the electrolyzer system to exceed the DOE 2012 efficiency target of 69%. GES significantly reduced the capital cost of a PEM electrolyzer stack through development of low cost components and fabrication methods, including a 60% reduction in stack parts count. Economic

  11. The hydrogen equation of state at high densities

    CERN Document Server

    Vorberger, J; Kraeft, W -D

    2011-01-01

    We use a two-fluid model combining the quantum Green's function technique for the electrons and a classical HNC description for the ions to calculate the high-density equation of state of hydrogen. This approach allows us to describe fully ionized plasmas of any electron degeneracy and any ionic coupling strength which are important for the modeling of a variety of astrophysical objects and inertial confinement fusion targets. We have also performed density functional molecular dynamics simulations (DFT-MD) and show that the data obtained agree with our approach in the high density limit. Good agreement is also found between DFT-MD and quantum Monte Carlo simulations. The thermodynamic properties of dense hydrogen can thus be obtained for the entire density range using only calculations in the physical picture.

  12. Superconductivity in hydrogen-rich materials at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Drozdov, Alexander

    2016-07-01

    A room temperature superconductor is probably one of the most desired systems in solid state physics. The highest critical temperature (T{sub c}) that has been achieved so far is in the copper oxide system: 133 kelvin (K) at ambient pressure ([82]Schilling et al. 1993) and 160 K under pressure ([42]Gao et al. 1994). The nature of superconductivity in the cuprates and in the recently discovered iron-based superconductor family (T{sub c}=57 K) is still not fully understood. In contrast, there is a class of superconductors which is well-described by the Bardeen, Cooper, Schrieffer (BCS) theory - conventional superconductors. Great efforts were spent in searching for high-temperature (T{sub c} > 77 K) conventional superconductor but only T{sub c} = 39 K has been reached in MgB2 ([68]Nagamatsu et al. 2001). BCS theory puts no bounds for T{sub c} as follows from Eliashberg's formulation of BCS theory. T{sub c} can be high, if there is a favorable combination of high-frequency phonons, strong electron-phonon coupling, and a high density of states. It does not predict however in which materials all three parameters are large. At least it gives a clear indication that materials with light elements are favorable as light elements provide high frequencies in the phonon spectrum. The lightest element is hydrogen, and Ashcroft made a first prediction that metallic hydrogen will be a high-temperature superconductor ([6]Ashcroft 1968). As pressure of hydrogen metallization was too high (about 400-500 GPa) for experimental techniques then he proposed that compounds dominated by hydrogen (hydrides) also might be good high temperature superconductors ([6]Ashcroft 1968; [7]Ashcroft 2004). A lot of the followed calculations supported this idea. T{sub c} in the range of 50-235 kelvin was predicted for many hydrides. Unfortunately, only a moderate T{sub c} of 17 kelvin has been observed experimentally ([27]Eremets et al. 2008) so far. A goal of the present work is to find a

  13. Highly fluorescent supramolecular gels with chirality transcription through hydrogen bonding.

    Science.gov (United States)

    Seo, Jangwon; Chung, Jong Won; Jo, Eun-Hye; Park, Soo Young

    2008-06-28

    A highly fluorescent organogel with transparency was formed through a hydrogen (H)-bonding interaction between a non-fluorescent and achiral 2-(3',5'-bis-trifluoromethyl-biphenyl-4-yl)-3-(4-pyridin-4-yl-phenyl)-acrylonitrile (CN-TFMBPPE) monomer and chiral sergeant l-tartaric acid (TA) (or d-TA), with gel formation being accompanied by a drastic fluorescence enhancement as well as chirality induction.

  14. Amorphous Alloy Membranes for High Temperature Hydrogen Separation

    Energy Technology Data Exchange (ETDEWEB)

    Coulter, K. [Southwest Research Inst. (SwRI), San Antonio, TX (United States)

    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

  15. Hydrogen Concentration in the Inner-Most Container within a Pencil Tank Overpack Packaged in a Standard Waste Box Package

    Energy Technology Data Exchange (ETDEWEB)

    Marusich, Robert M.

    2012-01-25

    A set of steady state diffusion flow equations, for the hydrogen diffusion from one bag to the next bag (or one plastic waste container to another), within a set of nested waste bags (or nested waste containers), are developed and presented. The input data is then presented and justified. Inputting the data for each volume and solving these equations yields the steady state hydrogen concentration in each volume. The input data (permeability of the bag surface and closure, dimensions and hydrogen generation rate) and equations are analyzed to obtain the hydrogen concentrations in the innermost container for a set of containers which are analyzed for the TRUCON code for the general waste containers and the TRUCON code for the Pencil Tank Overpacks (PTO) in a Standard Waste Box (SWB).

  16. How does the boron concentration affect hydrogen storage in lithium decorated zero- and two-dimensional boron-carbon compounds?

    Science.gov (United States)

    Ye, Xiao-Juan; Liu, Chun-Sheng; Jia, Ran; Zeng, Zhi; Zhong, Wei

    2013-02-21

    A balance between the hydrogen capacity and reversibility is a big challenge in the search for hydrogen storage materials. Using van der Waals-corrected density functional theory, we perform a detailed study of the hydrogen molecules adsorption on lithium (Li) decorated zero- and two-dimensional boron-carbon (B-C) compounds. It is found that not only the Li bond strength but also the number of adsorbed hydrogen molecules depends on the B concentration. First, the binding of Li on the B-C compounds strengthens with the increase of the B concentration due to the stronger hybridization between the lowest unoccupied molecular orbitals of the B-C compounds and Li 2p orbitals. Thus, Li atoms are not likely to form clusters, indicating a good reversible hydrogen storage. Second, higher B concentration results in weaker electric field produced by the charge transfer from Li to the B-C compounds. Therefore, one Li atom can adsorb up to 5H(2) molecules with the B concentration less than 50%. In contrast, the adsorption number of H(2) molecules is reduced to 4 when the B concentration is greater than or equal to 50%. Third, using a statistical model parametrized by the results of ab initio calculations, the adsorption and desorption of molecular hydrogens are calculated at ambient temperature and pressure. We find that the usable number of adsorbed H(2) per Li under ambient conditions decreases with the increase of B concentration. These results can serve as a guide in the design of new hydrogen storage materials based on B-C compounds.

  17. Hydrogen.

    Science.gov (United States)

    Bockris, John O'M

    2011-11-30

    The idea of a "Hydrogen Economy" is that carbon containing fuels should be replaced by hydrogen, thus eliminating air pollution and growth of CO₂ in the atmosphere. However, storage of a gas, its transport and reconversion to electricity doubles the cost of H₂ from the electrolyzer. Methanol made with CO₂ from the atmosphere is a zero carbon fuel created from inexhaustible components from the atmosphere. Extensive work on the splitting of water by bacteria shows that if wastes are used as the origin of feed for certain bacteria, the cost for hydrogen becomes lower than any yet known. The first creation of hydrogen and electricity from light was carried out in 1976 by Ohashi et al. at Flinders University in Australia. Improvements in knowledge of the structure of the semiconductor-solution system used in a solar breakdown of water has led to the discovery of surface states which take part in giving rise to hydrogen (Khan). Photoelectrocatalysis made a ten times increase in the efficiency of the photo production of hydrogen from water. The use of two electrode cells; p and n semiconductors respectively, was first introduced by Uosaki in 1978. Most photoanodes decompose during the photoelectrolysis. To avoid this, it has been necessary to create a transparent shield between the semiconductor and its electronic properties and the solution. In this way, 8.5% at 25 °C and 9.5% at 50 °C has been reached in the photo dissociation of water (GaP and InAs) by Kainthla and Barbara Zeleney in 1989. A large consortium has been funded by the US government at the California Institute of Technology under the direction of Nathan Lewis. The decomposition of water by light is the main aim of this group. Whether light will be the origin of the post fossil fuel supply of energy may be questionable, but the maximum program in this direction is likely to come from Cal. Tech.

  18. Diverse microbial species survive high ammonia concentrations

    Science.gov (United States)

    Kelly, Laura C.; Cockell, Charles S.; Summers, Stephen

    2012-04-01

    Planetary protection regulations are in place to control the contamination of planets and moons with terrestrial micro-organisms in order to avoid jeopardizing future scientific investigations relating to the search for life. One environmental chemical factor of relevance in extraterrestrial environments, specifically in the moons of the outer solar system, is ammonia (NH3). Ammonia is known to be highly toxic to micro-organisms and may disrupt proton motive force, interfere with cellular redox reactions or cause an increase of cell pH. To test the survival potential of terrestrial micro-organisms exposed to such cold, ammonia-rich environments, and to judge whether current planetary protection regulations are sufficient, soil samples were exposed to concentrations of NH3 from 5 to 35% (v/v) at -80°C and room temperature for periods up to 11 months. Following exposure to 35% NH3, diverse spore-forming taxa survived, including representatives of the Firmicutes (Bacillus, Sporosarcina, Viridibacillus, Paenibacillus, Staphylococcus and Brevibacillus) and Actinobacteria (Streptomyces). Non-spore forming organisms also survived, including Proteobacteria (Pseudomonas) and Actinobacteria (Arthrobacter) that are known to have environmentally resistant resting states. Clostridium spp. were isolated from the exposed soil under anaerobic culture. High NH3 was shown to cause a reduction in viability of spores over time, but spore morphology was not visibly altered. In addition to its implications for planetary protection, these data show that a large number of bacteria, potentially including spore-forming pathogens, but also environmentally resistant non-spore-formers, can survive high ammonia concentrations.

  19. The impact of furfural concentrations and substrate-to-biomass ratios on biological hydrogen production from synthetic lignocellulosic hydrolysate using mesophilic anaerobic digester sludge.

    Science.gov (United States)

    Akobi, Chinaza; Hafez, Hisham; Nakhla, George

    2016-12-01

    This study evaluated the impact of furfural (a furan derivative) on hydrogen production rates and yields at initial substrate-to-microorganism ratios (S°/X°) of 4, 2, 1, and 0.5gCOD/gVSS and furfural concentrations of 4, 2, 1, and 0.5g/L. Fermentation studies were carried out in batches using synthetic lignocellulosic hydrolysate as substrate and mesophilic anaerobic digester sludge as seed. Contrary to other literature studies where furfural was inhibitory, this study showed that furfural concentrations of up to 1g/L enhanced hydrogen production with yields as high as 19% from the control (batch without furfural). Plots of hydrogen yields against gfurfural/gsugars and hydrogen yields versus gfurfural/gbiomass showed negative linear correlation indicating that these parameters influence biohydrogen production. Regression analysis indicated that gfurfural/gsugarsinitial exerted a greater effect on the degree of inhibition of hydrogen production than gfurfural/gVSSfinal. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Searching for magnetism in hydrogenated graphene: using highly hydrogenated graphene prepared via Birch reduction of graphite oxides.

    Science.gov (United States)

    Eng, Alex Yong Sheng; Poh, Hwee Ling; Šaněk, Filip; Maryško, Miroslav; Matějková, Stanislava; Sofer, Zdeněk; Pumera, Martin

    2013-07-23

    Fully hydrogenated graphene (graphane) and partially hydrogenated graphene materials are expected to possess various fundamentally different properties from graphene. We have prepared highly hydrogenated graphene containing 5% wt of hydrogen via Birch reduction of graphite oxide using elemental sodium in liquid NH3 as electron donor and methanol as proton donor in the reduction. We also investigate the influence of preparation method of graphite oxide, such as the Staudenmaier, Hofmann or Hummers methods on the hydrogenation rate. A control experiment involving NaNH2 instead of elemental Na was also performed. The materials were characterized in detail by electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy both at room and low temperatures, X-ray fluorescence spectroscopy, inductively coupled plasma optical emission spectroscopy, combustible elemental analysis and electrical resistivity measurements. Magnetic measurements are provided of bulk quantities of highly hydrogenated graphene. In the whole temperature range up to room temperature, the hydrogenated graphene exhibits a weak ferromagnetism in addition to a contribution proportional to field that is caused not only by diamagnetism but also likely by an antiferromagnetic influence. The origin of the magnetism is also determined to arise from the hydrogenated graphene itself, and not as a result of any metallic impurities.

  1. High Flux Metallic Membranes for Hydrogen Recovery and Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Buxbaum, Robert

    2010-06-30

    We made and tested over 250 new alloys for use as lower cost, higher flux hydrogen extraction membrane materials. Most of these were intermetallic, or contained significant intermetallic content, particularly based on B2 alloy compositions with at least one refractory component; B2 intermetallics resemble BCC alloys, in structure, but the atoms have relatively fixed positions, with one atom at the corners of the cube, the other at the centers. The target materals we were looking for would contain little or no expensive elements, no strongly toxic or radioactive elements, would have high flux to hydrogen, while being fabricable, brazable, and relatively immune to hydrogen embrittlement and corrosion in operation. The best combination of properties of the membrane materials we developed was, in my opinion, a Pd-coated membrane consisting of V -9 atomic % Pd. This material was relatively cheap, had 5 times the flux of Pd under the same pressure differential, was reasonably easy to fabricate and braze, and not bad in terms of embrittlement. Based on all these factors we project, about 1/3 the cost of Pd, on an area basis for a membrane designed to last 20 years, or 1/15 the cost on a flux basis. Alternatives to this membrane replaced significant fractions of the Pd with Ni and or Co. The cost for these membranes was lower, but so was the flux. We produced successful brazed products from the membrane materials, and made them into flat sheets. We tested, unsuccessfully, several means of fabricating thematerials into tubes, and eventually built a membrane reactor using a new, flat-plate design: a disc and doughnut arrangement, a design that seems well- suited to clean hydrogen production from coal. The membranes and reactor were tested successfully at Western Research. A larger equipment company (Chart Industries) produced similar results using a different flat-plate reactor design. Cost projections of the membrane are shown to be attractive.

  2. Molecular basis of high viscosity in concentrated antibody solutions: Strategies for high concentration drug product development

    OpenAIRE

    Tomar, Dheeraj S.; Kumar, Sandeep; Singh, Satish K.; Goswami, Sumit; Li, Li

    2016-01-01

    Effective translation of breakthrough discoveries into innovative products in the clinic requires proactive mitigation or elimination of several drug development challenges. These challenges can vary depending upon the type of drug molecule. In the case of therapeutic antibody candidates, a commonly encountered challenge is high viscosity of the concentrated antibody solutions. Concentration-dependent viscosity behaviors of mAbs and other biologic entities may depend on pairwise and higher-or...

  3. Detonation propagation in hydrogen-air mixtures with transverse concentration gradients

    Science.gov (United States)

    Boeck, L. R.; Berger, F. M.; Hasslberger, J.; Sattelmayer, T.

    2016-03-01

    The influence of transverse concentration gradients on detonation propagation in H_2-air mixtures is investigated experimentally in a wide parameter range. Detonation fronts are characterized by means of high-speed shadowgraphy, OH* imaging, pressure measurements, and soot foils. Steep concentration gradients at low average H_2 concentrations lead to single-headed detonations. A maximum velocity deficit compared to the Chapman-Jouguet velocity of 9 % is observed. Significant amounts of mixture seem to be consumed by turbulent deflagration behind the leading detonation. Wall pressure measurements show high local pressure peaks due to strong transverse waves caused by the concentration gradients. Higher average H_2 concentrations or weaker gradients allow for multi-headed detonation propagation.

  4. Hydrogen

    Directory of Open Access Journals (Sweden)

    John O’M. Bockris

    2011-11-01

    Full Text Available The idea of a “Hydrogen Economy” is that carbon containing fuels should be replaced by hydrogen, thus eliminating air pollution and growth of CO2 in the atmosphere. However, storage of a gas, its transport and reconversion to electricity doubles the cost of H2 from the electrolyzer. Methanol made with CO2 from the atmosphere is a zero carbon fuel created from inexhaustible components from the atmosphere. Extensive work on the splitting of water by bacteria shows that if wastes are used as the origin of feed for certain bacteria, the cost for hydrogen becomes lower than any yet known. The first creation of hydrogen and electricity from light was carried out in 1976 by Ohashi et al. at Flinders University in Australia. Improvements in knowledge of the structure of the semiconductor-solution system used in a solar breakdown of water has led to the discovery of surface states which take part in giving rise to hydrogen (Khan. Photoelectrocatalysis made a ten times increase in the efficiency of the photo production of hydrogen from water. The use of two electrode cells; p and n semiconductors respectively, was first introduced by Uosaki in 1978. Most photoanodes decompose during the photoelectrolysis. To avoid this, it has been necessary to create a transparent shield between the semiconductor and its electronic properties and the solution. In this way, 8.5% at 25 °C and 9.5% at 50 °C has been reached in the photo dissociation of water (GaP and InAs by Kainthla and Barbara Zeleney in 1989. A large consortium has been funded by the US government at the California Institute of Technology under the direction of Nathan Lewis. The decomposition of water by light is the main aim of this group. Whether light will be the origin of the post fossil fuel supply of energy may be questionable, but the maximum program in this direction is likely to come from Cal. Tech.

  5. A 15 year record of high-frequency, in situ measurements of hydrogen at Mace Head, Ireland

    Directory of Open Access Journals (Sweden)

    A. Grant

    2010-02-01

    Full Text Available Continuous high-frequency measurements of atmospheric molecular hydrogen have been made at Mace Head atmospheric research station on the west coast of Ireland from March 1994 to December 2008. The presented data provides information on long term trends and seasonal cycles of hydrogen in background northern hemispheric air. Individual measurements have been sorted using a Lagrangian dispersion model to separate clean background air from regionally polluted European air masses and those transported from southerly latitudes. No significant trend was observed in background northern hemispheric air over the 15 year record, elevations in yearly means were accounted for from large scale biomass burning events. Seasonal cycles show the expected pattern with maxima in spring and minima in late autumn. The mean hydrogen mole fraction in baseline northern hemispheric air was found to be 500.1 ppb. Air transported from southerly latitudes showed an elevation from baseline mean of 11.0 ppb, reflecting both the latitudinal gradient of hydrogen, with higher concentrations in the Southern Hemisphere, and the photochemical source of hydrogen from low northern latitudes. European polluted air masses arriving at Mace Head showed mean elevation of 5.3 ppb from baseline air masses, reflecting hydrogen's source from primary emissions like fossil fuel combustion. Forward modelling of transport of hydrogen to Mace Head suggests that the ratio of hydrogen to carbon monoxide in primary emissions is considerably less in non-traffic sources than traffic sources.

  6. LOX vaporization in high-pressure, hydrogen-rich gas

    Science.gov (United States)

    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.

  7. The effect of hydrogen peroxide concentration on metal ion release from dental casting alloys.

    Science.gov (United States)

    Al-Salehi, S K; Hatton, P V; Johnson, A; Cox, A G; McLeod, C

    2008-04-01

    There are concerns that tooth bleaching agents may adversely affect dental materials. The aim of this study was to test the hypothesis that increasing concentrations of hydrogen peroxide (HP) are more effective than water at increasing metal ion release from two typical dental casting alloys during bleaching. Discs (n = 28 for each alloy) were prepared by casting and heat treated to simulate a typical porcelain-firing cycle. Discs (n = 7) of each alloy were immersed in either 0%, 3%, 10% or 30% (w/v) HP solutions for 24 h at 37 degrees C. Samples were taken for metal ion release determination using inductively coupled plasma-mass spectrometry and the data analysed using a two-way anova followed by a one-way anova. The surface roughness of each disc was measured using a Talysurf contact profilometer before and after bleaching and the data analysed using a paired t-test. With the exception of gold, the differences in metal ion concentration after treatment with 0% (control) and each of 3%, 10% and 30% HP (w/v) were statistically significant (P 0.05) Exposure of the two dental casting alloys to HP solutions increased metal ion release of all the elements except gold.

  8. Fracture Analysis of Rubber Sealing Material for High Pressure Hydrogen Vessel

    National Research Council Canada - National Science Library

    YAMABE, Junichiro; FUJIWARA, Hirotada; NISHIMURA, Shin

    2011-01-01

    In order to clarify the influence of high pressure hydrogen gas on mechanical damage in a rubber O-ring, the fracture analysis of the O-ring used for a sealing material of a pressure hydrogen vessel was conducted...

  9. Active Edge Sites Engineering in Nickel Cobalt Selenide Solid Solutions for Highly Efficient Hydrogen Evolution

    KAUST Repository

    Xia, Chuan

    2017-01-06

    An effective multifaceted strategy is demonstrated to increase active edge site concentration in NiCoSe solid solutions prepared by in situ selenization process of nickel cobalt precursor. The simultaneous control of surface, phase, and morphology result in as-prepared ternary solid solution with extremely high electrochemically active surface area (C = 197 mF cm), suggesting significant exposure of active sites in this ternary compound. Coupled with metallic-like electrical conductivity and lower free energy for atomic hydrogen adsorption in NiCoSe, identified by temperature-dependent conductivities and density functional theory calculations, the authors have achieved unprecedented fast hydrogen evolution kinetics, approaching that of Pt. Specifically, the NiCoSe solid solutions show a low overpotential of 65 mV at -10 mV cm, with onset potential of mere 18 mV, an impressive small Tafel slope of 35 mV dec, and a large exchange current density of 184 μA cm in acidic electrolyte. Further, it is shown that the as-prepared NiCoSe solid solution not only works very well in acidic electrolyte but also delivers exceptional hydrogen evolution reaction (HER) performance in alkaline media. The outstanding HER performance makes this solid solution a promising candidate for mass hydrogen production.

  10. Combined Solid State and High Pressure Hydrogen Storage

    DEFF Research Database (Denmark)

    Grube, Elisabeth; Jensen, Torben René

    Presented at The First European Early Stage Researcher's Conference on Hydrogen Storage in Belgrade, Serbia.......Presented at The First European Early Stage Researcher's Conference on Hydrogen Storage in Belgrade, Serbia....

  11. Highly active iridium catalyst for hydrogen production from formic acid

    Institute of Scientific and Technical Information of China (English)

    Ying Du; Yang-Bin Shen; Yu-Lu Zhan; Fan-Di Ning; Liu-Ming Yan; Xiao-Chun Zhou

    2017-01-01

    Formic acid (FA) dehydrogenation has attracted a lot of attentions since it is a convenient method for H2 production.In this work,we designed a self-supporting fuel cell system,in which H2 from FA is supplied into the fuel cell,and the exhaust heat from the fuel cell supported the FA dehydrogenation.In order to realize the system,we synthesized a highly active and selective homogeneous catalyst IrCp*Cl2bpym for FA dehydrogenation.The turnover frequency (TOF) of the catalyst for FA dehydrogenation is as high as 7150 h-1 at 50 ℃,and is up to 144,000 h-1 at 90 ℃.The catalyst also shows excellent catalytic stability for FA dehydrogenation after several cycles of test.The conversion ratio of FA can achieve 93.2%,and no carbon monoxide is detected in the evolved gas.Therefore,the evolved gas could be applied in the proton exchange membrane fuel cell (PEMFC) directly.This is a potential technology for hydrogen storage and generation.The power density of the PEMFC driven by the evolved gas could approximate to that using pure hydrogen.

  12. Effect of initial bacteria concentration on hydrogen gas production from cheese whey powder solution by thermophilic dark fermentation.

    Science.gov (United States)

    Kargi, Fikret; Eren, Nur Seza; Ozmihci, Serpil

    2012-07-01

    Dark fermentative hydrogen gas production from cheese whey powder solution was realized at 55°C. Experiments were performed at different initial biomass concentrations varying between 0.48 and 2.86 g L(-1) with a constant initial substrate concentration of 26 ± 2 g total sugar (TS) per liter. The highest cumulative hydrogen evolution (633 mL, 30°C), hydrogen yield (1.56 mol H(2) mol(-1) glucose), and H(2) formation rate (3.45 mL h(-1) ) were obtained with 1.92 g L(-1) biomass concentration. The specific H(2) production rate decreased with increasing biomasss concentration from the highest value (47.7 mL g(-1) h(-1) ) at 0.48 g L(-1) biomass concentration. Total volatile fatty acid concentration varied beetween 10 and 14 g L(-1) with the highest level of 14.2 g L(-1) at biomass concentration of 0.48 g L(-1) and initial TS content of 28.4 g L(-1) . The experimental data were correlated with the Gompertz equation and the constants were determined. The most suitable initial biomass to substrate ratio yielding the highest H(2) yield and formation rate was 0.082 g biomass per gram of TS. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

  13. Seeing Hydrogen in Colors: Low-Cost and Highly Sensitive Eye Readable Hydrogen Detectors

    NARCIS (Netherlands)

    Ngene, P.; Radeva, T.; Slaman, M.J.; Westerwaal, R.J.; Schreuders, H.; Dam, B.

    2014-01-01

    There is a great interest in the development of reliable and low-cost hydrogen sensors for applications in the hydrogen economy, industrial processes, space application, detection of environmental pollution, and biomedical applications. Here, a new type of optical detector that indicates the

  14. Molecular basis of high viscosity in concentrated antibody solutions: Strategies for high concentration drug product development.

    Science.gov (United States)

    Tomar, Dheeraj S; Kumar, Sandeep; Singh, Satish K; Goswami, Sumit; Li, Li

    2016-01-01

    Effective translation of breakthrough discoveries into innovative products in the clinic requires proactive mitigation or elimination of several drug development challenges. These challenges can vary depending upon the type of drug molecule. In the case of therapeutic antibody candidates, a commonly encountered challenge is high viscosity of the concentrated antibody solutions. Concentration-dependent viscosity behaviors of mAbs and other biologic entities may depend on pairwise and higher-order intermolecular interactions, non-native aggregation, and concentration-dependent fluctuations of various antibody regions. This article reviews our current understanding of molecular origins of viscosity behaviors of antibody solutions. We discuss general strategies and guidelines to select low viscosity candidates or optimize lead candidates for lower viscosity at early drug discovery stages. Moreover, strategies for formulation optimization and excipient design are also presented for candidates already in advanced product development stages. Potential future directions for research in this field are also explored.

  15. Effect of the ergot derivative lisuride hydrogen maleate on serum prolactin concentrations in female rats.

    Science.gov (United States)

    Gräf, K J; Neumann, F; Horowski, R

    1976-03-01

    The influence of a new synthetic ergot derivative, lisuride hydrogen maleate (LHM) on serum prolactin (PRL) concentrations was investigated in female rats using different test models: 1. in reserpine (R)-pretreated intact females, and 2. in ovariectomized (OVX) estradiol benzoate (E2)-primed animals with or without an additional pretreatment with R. In all the models used LHM was strongly effective in lowering serum PRL. Doses from 0.025 to 0.5 mg/kg LHM, given orally as well as subcutaneously, suppressed serum PRL. Depending on the dose used, the serum PRL was lowered to a different extent for up to 12 h. LHM was at least as effective as the well-known potent inhibitor of PRL secretion CB-154 in lowering serum PRL in OVX rats primed with E2. The effects of R, E2, and LHM are described in relation to their mode of action within the hypothalamic-hypophyseal system which regulates PRL secretion. While the increase in serum PRL induced by R seems to be directly relatable to its known catecholamine depletion, the circadian rhythm of PRL secretion induced by E2 seems to be influenced or mediated by central neural mechanisms. The effects of LHM on serum PRL in these test models can be related to its dopaminergic action and constitute further evidence for the central functions of dopaminergic mechanisms in the regulation of PRL secretion.

  16. Transport properties of liquid metal hydrogen under high pressures

    Science.gov (United States)

    Brown, R. C.; March, N. H.

    1972-01-01

    A theory is developed for the compressibility and transport properties of liquid metallic hydrogen, near to its melting point and under high pressure. The interionic force law is assumed to be of the screened Coulomb type, because hydrogen has no core electrons. The random phase approximation is used to obtain the structure factor S(k) of the system in terms of the Fourier transform of this force law. The long wavelenth limit of the structure factor S(o) is related to the compressibility, which is much lower than that of alkali metals at their melting points. The diffusion constant at the melting point is obtained in terms of the Debye frequency, using a frequency spectrum analogous with the phonon spectrum of a solid. A similar argument is used to obtain the combined shear and bulk viscosities, but these depend also on S(o). The transport coefficients are found to be about the same size as those of alkali metals at their melting points.

  17. Photonic crystal fiber modal interferometer with Pd/WO3 coating for real-time monitoring of dissolved hydrogen concentration in transformer oil.

    Science.gov (United States)

    Zhang, Ya-Nan; Wu, Qilu; Peng, Huijie; Zhao, Yong

    2016-12-01

    A highly-sensitive and temperature-robust photonic crystal fiber (PCF) modal interferometer coated with Pd/WO3 film was fabricated and studied, aiming for real-time monitoring of dissolved hydrogen concentration in transformer oil. The sensor probe was fabricated by splicing two segments of a single mode fiber (SMF) with both ends of the PCF. Since the collapse of air holes in the PCF in the interfaces between SMF and PCF, a SMF-PCF-SMF interferometer structure was formed. The Pd/WO3 film was fabricated by sol-gel method and coated on the surface of the PCF by dip-coating method. When the Pd/WO3 film is exposed to hydrogen, both the length and cladding refractive index of the PCF would be changed, resulting in the resonant wavelength shift of the interferometer. Experimental results showed that the hydrogen measurement sensitivity of the proposed sensor can reach 0.109 pm/(μl/l) in the transformer oil, with the measurement range of 0-10 000 μl/l and response time less than 33 min. Besides, the proposed sensor was temperature-insensitive without any compensation process, easy to fabricate without any tapering, polishing, or etching process, low cost and quickly response without any oil-gas separation device. All these performances satisfy the actual need of real-time monitoring of dissolved hydrogen concentration in the transformer oil.

  18. Sensitivity to temperature and material properties of hydrogen concentration at a crack tip in austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Schembri, Philip E [Los Alamos National Laboratory

    2008-01-01

    It is well known that dissolved hydrogen interacts with the stress field at a crack tip, with one result being an intensification of the hydrogen concentration in the region of maximum crack tip stress. The current paper presents recent calculations in ongoing efforts to use coupled stress-diffusion finite element analyses to aid in the structural integrity assessment of pressure vessels containing tritium. The focus of the current work is quantification of the effect of material properties (structural and diffusion) and temperature on the values of maximum stress and hydrogen concentration at the tip of a crack. A one-way-coupled finite element model of a compact tension specimen is used in which the effect of stress and trapping on the hydrogen diffusion is accounted for. Results show that, within the ranges of inputs considered, maximum stress varies approximately linearly with a material's room temperature yield stress but nonlinearly with temperature. Also, peak lattice hydrogen is shown to be a strong function of solubility parameters, a moderate function of yield stress, but only a weak function of trap binding energy and density when trap density is relatively low.

  19. Nitrophenylboronic acids as highly chemoselective probes to detect hydrogen peroxide in foods and agricultural products.

    Science.gov (United States)

    Lu, Chun-Ping; Lin, Chieh-Ti; Chang, Ching-Ming; Wu, Shih-Hsiung; Lo, Lee-Chiang

    2011-11-09

    Hydrogen peroxide is commonly used in the food processing industry as a chlorine-free bleaching and sterilizing agent, but excessive amounts of residual hydrogen peroxide have led to cases of food poisoning. Here we describe the development of a novel nonenzymatic colorimetric method for the determination of residual hydrogen peroxide in foods and agricultural products. Nitrophenylboronic acids chemoselectively react with hydrogen peroxide under alkaline conditions to produce yellow nitrophenolates. Of the three nitrophenylboronic acid isomers tested, the p-isomer displayed the highest sensitivity for hydrogen peroxide and the fastest reaction kinetics. The reaction product, p-nitrophenolate, has an absorption maximum at 405 nm and a good linear correlation between the hydrogen peroxide concentration and the A(405) values was obtained. We successfully applied this convenient and rapid method for hydrogen peroxide determination to samples of dried bean curds and disposable chopsticks, thereby demonstrating its potential in foods and agricultural industries.

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

    Science.gov (United States)

    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.

  1. High Temperature Equation of State of Metallic Hydrogen

    OpenAIRE

    V.T.Shvets

    2016-01-01

    The equation of state of liquid metallic hydrogen is solved numerically. Investigations are carried out at temperatures, 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 and proton interaction is applied to determine t...

  2. Neutron and high-pressure X-ray diffraction study of hydrogen-bonded ferroelectric rubidium hydrogen sulfate.

    Science.gov (United States)

    Binns, Jack; McIntyre, Garry J; Parsons, Simon

    2016-12-01

    The pressure- and temperature-dependent phase transitions in the ferroelectric material rubidium hydrogen sulfate (RbHSO4) are investigated by a combination of neutron Laue diffraction and high-pressure X-ray diffraction. The observation of disordered O-atom positions in the hydrogen sulfate anions is in agreement with previous spectroscopic measurements in the literature. Contrary to the mechanism observed in other hydrogen-bonded ferroelectric materials, H-atom positions are well defined and ordered in the paraelectric phase. Under applied pressure RbHSO4 undergoes a ferroelectric transition before transforming to a third, high-pressure phase. The symmetry of this phase is revised to the centrosymmetric space group P21/c, resulting in the suppression of ferroelectricity at high pressure.

  3. The effect of methanogenesis inhibition, inoculum and substrate concentration on hydrogen and carboxylic acids production from cassava wastewater.

    Science.gov (United States)

    Amorim, Norma C S; Amorim, Eduardo L C; Kato, Mario T; Florencio, Lourdinha; Gavazza, Savia

    2017-11-11

    Manipueira is a carbohydrate-rich agro-industrial waste from cassava processing. It is considered well suitable for biotechnological processes, such as hydrogen and carboxylic acids production, due to the high content of easily degradable organic matter. However, the proper methanogenesis inhibition method, inoculum type, and organic loads are factors still limiting the processes. The objective in this work was to evaluate the effects of such factors on byproducts production in anaerobic reactors. Batch experiments were conducted with 2.3-L flasks during two operational phases. In the first phase (P1), inhibition of methanogens in the sludge was evaluated using acetylene (1% v/v of headspace) and heat treatment (120 °C, 1 atm for 30 min). In the second phase (P2), three inoculum types obtained from common anaerobic sludges (bovine rumen and sludges from municipal and textile industrial wastewater treatment plants) were individually assayed. P2 aimed to identify the best inoculum, based on hydrogen production ability, which was tested for three initial concentrations of manipueira in terms of chemical oxygen demand (COD) (10, 20 and 40 g O2/L). Results of P1 indicated that either acetylene or heat treatment efficiently inhibited methanogenesis, with no methane production. However, the maximum H2 production potential by applying heat treatment (~ 563 mL) was more than twice compared with that by acetylene treatment (~ 257 mL); and butyrate was the main carboxylic acid by-product (~ 3 g/L). In P2 experiments after sludge heat treatment, the highest hydrogen yield (1.66 ± 0.07 mol H2/mol glucose) and caproic acid production (~ 2 g/L) were observed at 20 g O2/L of manipueira COD, when bovine rumen was the inoculum. The primary metabolic degradation products in all P2 experiments were ethanol, acetic, butyric, propionic and caproic acids. The finding of caproic acid detection indicated that the applied conditions in manipueira anaerobic degradation

  4. Spatial and temporal variations and factors controlling the concentrations of hydrogen peroxide and organic peroxides in rivers

    OpenAIRE

    Mostofa, Khan M. G.; Sakugawa, Hiroshi

    2009-01-01

    Hydrogen peroxide (H2O2) and organic peroxides (ROOH) were examined in water samples collected from the upstream and downstream sites of two Japanese rivers (the Kurose and the Ohta). H2O2 concentrations during monthly measurements varied between 6 and 213nM in the Kurose River and 33 and 188nM in the Ohta River. ROOH varied between 0 and 73nM in the Kurose River and 1 and 80nM in the Ohta. Concentrations of peroxides were higher during the summer months than in winter. H2O2 concentrations co...

  5. High-temperature nuclear reactor power plant cycle for hydrogen and electricity production – numerical analysis

    Directory of Open Access Journals (Sweden)

    Dudek Michał

    2016-01-01

    Full Text Available High temperature gas-cooled nuclear reactor (called HTR or HTGR for both electricity generation and hydrogen production is analysed. The HTR reactor because of the relatively high temperature of coolant could be combined with a steam or gas turbine, as well as with the system for heat delivery for high-temperature hydrogen production. However, the current development of HTR’s allows us to consider achievable working temperature up to 750°C. Due to this fact, industrial-scale hydrogen production using copper-chlorine (Cu-Cl thermochemical cycle is considered and compared with high-temperature electrolysis. Presented calculations show and confirm the potential of HTR’s as a future solution for hydrogen production without CO2 emission. Furthermore, integration of a hightemperature nuclear reactor with a combined cycle for electricity and hydrogen production may reach very high efficiency and could possibly lead to a significant decrease of hydrogen production costs.

  6. Development of Press Hardening Steel with High Resistance to Hydrogen Embrittlement

    Science.gov (United States)

    Bian, Jian; Mohrbacher, Hardy; Lu, Hongzhou; Wang, Wenjun

    Press hardening has become the state-of-art technology in the car body manufacturing to enhance safety standard and to reduce CO2 emission of new vehicles. However the delayed cracking due to hydrogen embrittlement remains to be a critical issue. Generally press hardening steel is susceptible to hydrogen embrittlement due to ultra-high strength and martensitic microstructure. The hydrogen charging tests clearly demonstrate that only a few ppm of diffusible hydrogen is sufficient to cause such embrittlement. Currently the hydrogen embrittlement cannot be detected in the press hardened components and the embitteled components could collapse in the crash situation with fatal consequences arisen through dramatic loss in both strength and ductility. This paper introduces a new metallurgical solution to increase the resistance to hydrogen embrittlement of conventional press hardening steel based on 22MnB5 by Nb microalloying. In the hydrogen embrittlement and permeation tests the impact of Nb microalloying on the hydrogen embrittlement behavior was investigated under different hydrogen charging conditions and constant load. The test results revealed that Nb addition increases the resistance to hydrogen embrittlement due to reduced hydrogen diffusivity. The focus of this paper is to investigate the precipitation behavior of microalloying elements by using TEM and STEM and to find out the mechanisms leading to higher performance against hydrogen embrittlement of Nb alloyed steels.

  7. High microparticle concentration in cord plasma.

    Science.gov (United States)

    Schweintzger, S; Schlagenhauf, A; Rinner, B; Bernhard, H; Novak, M; Leschnik, B; Muntean, W

    2010-11-01

    We investigated if differences in the microparticle concentration and activity between newborn cord plasma and adult plasma exist. To enumerate and characterize microparticles (MP) FACS and ELISA were used.The effect of microparticles derived tissue factor (TF) on thrombin generation was measured indirectly by CAT (calibrated automated thrombography). The flow cytometric measurements revealed an increased microparticle concentration in newborn cord compared with adult plasma. By the use of ELISA a significantly increased procoagulant activity of microparticles was found in newborn cord plasma as compared to adult plasma. Initiation of thrombin generation by adding phospholipids alone resulted in a significant lower prolongation of the lag time, time to peak in cord plasma, while the decrease of endogenous thrombin potential (ETP) and peak was comparable between newborns and adults. Our results show a higher impact of microparticles on the haemostatic system of newborns than on that of adults. The three methods suggest a somewhat increased microparticle activity in newborn cord plasma, but argue against strong platelet activation during birth.

  8. Practical-scale tests of cryogenic molecular sieve for separating low-concentration hydrogen isotopes from helium

    Science.gov (United States)

    Willms, R. S.; Taylor, D. J.; Enoeda, Mikio; Okuno, Kenji

    1994-04-01

    Earlier bench-scale work at the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory examined a number of adsorbents for their suitability for separating low-concentration hydrogen (no tritium) from helium. One of the effective adsorbents was Linde 5A molecular sieve. Recently, experiments including tritium were conducted using practical-scale adsorbers. These tests used existing cryogenic molecular sieve beds (CMSB's) which each contain about 1.6 kg of Linde 5A molecular sieve. They are part of the TSTA integrated tritium processing system. Gas was fed to each CMSB at about 13 SLPM with a nominal composition of 99% He, 0.98% H2, and 0.02% HT. In all cases, for an extended period of time, the beds allowed no detectable (via Raman spectroscopy) hydrogen isotopes to escape in the bed effluent. Thereafter, the hydrogen isotopes appeared in the bed exit with a relatively sharp breakthrough curve. This work concludes that cryogenic molecular sieve adsorption is a practical and effective means of separating low-concentration hydrogen isotopes from a helium carrier.

  9. Storage of hydrogen by high pressure microencapsulation in glass

    Science.gov (United States)

    Yan, K. L.; Sellars, B. G.; Lo, J.; Johar, S.; Murthy, M. K.

    The storage of compressed hydrogen gas in cylindrical glass microcapsules is a new concept that offers potential merits of lightweight, low cost, and simplicity in system design. The strongly temperature dependent permeability of candidate glass materials to hydrogen gas allows compressed hydrogen gas to be stored and retrieved from microcapsules at required rates by appropriate temperature adjustments. The major emphasis of work has been placed on developing the processes and techniques for hollow fibre drawing, fabrication of microcapsules and test modules, evaluation of microcapsule properties, and laboratory-scale hydrogen charge and discharge trials. These development efforts were followed by those for refinement and optimization, with particular interest in improving microcapsule strength and dimensional consistency. Recently, axial tensile strengths of over 700 MPa were achieved for microcapsules with aspect ratios higher than 25:1. Hydrogen storage capacity of over 2 wt percent has been demonstrated in laboratory trials.

  10. High Temperature Equation of State of Metallic Hydrogen

    CERN Document Server

    Shvets, V T

    2016-01-01

    The equation of state of liquid metallic hydrogen is solved numerically. Investigations are carried out at temperatures, 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 and 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 interproton 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 thirdorder perturbation theory terms. The third-order term proves to be rather essential at moderately hig...

  11. Numerical and Experimental Study of Mixing Processes Associated with Hydrogen and High Hydrogen Content Fuels

    Energy Technology Data Exchange (ETDEWEB)

    McDonell, Vincent; Hill, Scott; Akbari, Amin; McDonell, Vincent

    2011-09-30

    As simulation capability improves exponentially with increasingly more cost effective CPUs and hardware, it can be used ?routinely? for engineering applications. Many commercial products are available and they are marketed as increasingly powerful and easy to use. The question remains as to the overall accuracy of results obtained. To support the validation of the CFD, a hierarchical experiment was established in which the type of fuel injection (radial, axial) as well as level of swirl (non-swirling, swirling) could be systematically varied. The effort was limited to time efficient approaches (i.e., generally RANS approaches) although limited assessment of time resolved methods (i.e., unsteady RANS and LES) were considered. Careful measurements of the flowfield velocity and fuel concentration were made using both intrusive and non-intrusive methods. This database was then used as the basis for the assessment of the CFD approach. The numerical studies were carried out with a statistically based matrix. As a result, the effect of turbulence model, fuel type, axial plane, turbulent Schmidt number, and injection type could be studied using analysis of variance. The results for the non-swirling cases could be analyzed as planned, and demonstrate that turbulence model selection, turbulence Schmidt number, and the type of injection will strongly influence the agreement with measured values. Interestingly, the type of fuel used (either hydrogen or methane) has no influence on the accuracy of the simulations. For axial injection, the selection of proper turbulence Schmidt number is important, whereas for radial injection, the results are relatively insensitive to this parameter. In general, it was found that the nature of the flowfield influences the performance of the predictions. This result implies that it is difficult to establish a priori the ?best? simulation approach to use. However, the insights from the relative orientation of the jet and flow do offer some

  12. Alloy and composition dependence of hydrogen embrittlement susceptibility in high-strength steel fasteners

    Science.gov (United States)

    Brahimi, S. V.; Yue, S.; Sriraman, K. R.

    2017-06-01

    High-strength steel fasteners characterized by tensile strengths above 1100 MPa are often used in critical applications where a failure can have catastrophic consequences. Preventing hydrogen embrittlement (HE) failure is a fundamental concern implicating the entire fastener supply chain. Research is typically conducted under idealized conditions that cannot be translated into know-how prescribed in fastener industry standards and practices. Additionally, inconsistencies and even contradictions in fastener industry standards have led to much confusion and many preventable or misdiagnosed fastener failures. HE susceptibility is a function of the material condition, which is comprehensively described by the metallurgical and mechanical properties. Material strength has a first-order effect on HE susceptibility, which increases significantly above 1200 MPa and is characterized by a ductile-brittle transition. For a given concentration of hydrogen and at equal strength, the critical strength above which the ductile-brittle transition begins can vary due to second-order effects of chemistry, tempering temperature and sub-microstructure. Additionally, non-homogeneity of the metallurgical structure resulting from poorly controlled heat treatment, impurities and non-metallic inclusions can increase HE susceptibility of steel in ways that are measurable but unpredictable. Below 1200 MPa, non-conforming quality is often the root cause of real-life failures. This article is part of the themed issue 'The challenges of hydrogen and metals'.

  13. Production of carbon monoxide-free hydrogen and helium from a high-purity source

    Science.gov (United States)

    Golden, Timothy Christopher [Allentown, PA; Farris, Thomas Stephen [Bethlehem, PA

    2008-11-18

    The invention provides vacuum swing adsorption processes that produce an essentially carbon monoxide-free hydrogen or helium gas stream from, respectively, a high-purity (e.g., pipeline grade) hydrogen or helium gas stream using one or two adsorber beds. By using physical adsorbents with high heats of nitrogen adsorption, intermediate heats of carbon monoxide adsorption, and low heats of hydrogen and helium adsorption, and by using vacuum purging and high feed stream pressures (e.g., pressures of as high as around 1,000 bar), pipeline grade hydrogen or helium can purified to produce essentially carbon monoxide -free hydrogen and helium, or carbon monoxide, nitrogen, and methane-free hydrogen and helium.

  14. High-Yield Hydrogen Production from Starch and Water by a Synthetic Enzymatic Pathway

    Science.gov (United States)

    Zhang, Y.-H. Percival; Evans, Barbara R.; Mielenz, Jonathan R.; Hopkins, Robert C.; Adams, Michael W.W.

    2007-01-01

    Background The future hydrogen economy offers a compelling energy vision, but there are four main obstacles: hydrogen production, storage, and distribution, as well as fuel cells. Hydrogen production from inexpensive abundant renewable biomass can produce cheaper hydrogen, decrease reliance on fossil fuels, and achieve zero net greenhouse gas emissions, but current chemical and biological means suffer from low hydrogen yields and/or severe reaction conditions. Methodology/Principal Findings Here we demonstrate a synthetic enzymatic pathway consisting of 13 enzymes for producing hydrogen from starch and water. The stoichiometric reaction is C6H10O5 (l)+7 H2O (l)→12 H2 (g)+6 CO2 (g). The overall process is spontaneous and unidirectional because of a negative Gibbs free energy and separation of the gaseous products with the aqueous reactants. Conclusions Enzymatic hydrogen production from starch and water mediated by 13 enzymes occurred at 30°C as expected, and the hydrogen yields were much higher than the theoretical limit (4 H2/glucose) of anaerobic fermentations. Significance The unique features, such as mild reaction conditions (30°C and atmospheric pressure), high hydrogen yields, likely low production costs ($∼2/kg H2), and a high energy-density carrier starch (14.8 H2-based mass%), provide great potential for mobile applications. With technology improvements and integration with fuel cells, this technology also solves the challenges associated with hydrogen storage, distribution, and infrastructure in the hydrogen economy. PMID:17520015

  15. High-yield hydrogen production from starch and water by a synthetic enzymatic pathway.

    Directory of Open Access Journals (Sweden)

    Y-H Percival Zhang

    Full Text Available BACKGROUND: The future hydrogen economy offers a compelling energy vision, but there are four main obstacles: hydrogen production, storage, and distribution, as well as fuel cells. Hydrogen production from inexpensive abundant renewable biomass can produce cheaper hydrogen, decrease reliance on fossil fuels, and achieve zero net greenhouse gas emissions, but current chemical and biological means suffer from low hydrogen yields and/or severe reaction conditions. METHODOLOGY/PRINCIPAL FINDINGS: Here we demonstrate a synthetic enzymatic pathway consisting of 13 enzymes for producing hydrogen from starch and water. The stoichiometric reaction is C(6H(10O(5 (l+7 H(2O (l-->12 H(2 (g+6 CO(2 (g. The overall process is spontaneous and unidirectional because of a negative Gibbs free energy and separation of the gaseous products with the aqueous reactants. CONCLUSIONS: Enzymatic hydrogen production from starch and water mediated by 13 enzymes occurred at 30 degrees C as expected, and the hydrogen yields were much higher than the theoretical limit (4 H(2/glucose of anaerobic fermentations. SIGNIFICANCE: The unique features, such as mild reaction conditions (30 degrees C and atmospheric pressure, high hydrogen yields, likely low production costs ($ approximately 2/kg H(2, and a high energy-density carrier starch (14.8 H(2-based mass%, provide great potential for mobile applications. With technology improvements and integration with fuel cells, this technology also solves the challenges associated with hydrogen storage, distribution, and infrastructure in the hydrogen economy.

  16. High Hydrogen Loading of Thin Palladium Wires Through

    CERN Document Server

    Celani, F; Marini, P; Di Stefano, V; Nakamura, M; Pace, S; Vecchione, A; Mancini, A; Tripodi, P; Di Gioacchino, D

    2000-01-01

    A new protocol for the electrolytic loading of hydrogen (H) in thin palladium (Pd) wires has been developed. In order to increase the cathodic overvoltage, which is known to be the main parameter capable to enhance the electrolytic $9 H loading of Pd, the catalytic action of the Pd surface versus H-H recombination has been strongly reduced by precipitation of a thin layer of alkaline-earth carbonates on the cathode. A set of electrolytes has been employed, $9 containing small amounts of hydrochloric or sulphuric acid and strontium or calcium ions. The H loading has been continuously evaluated through ac measurements of the Pd wire resistance. Uncommonly low resistivity values, leading to $9 an estimate of exceptionally high H loading, have been observed. Evidence of the existence of a new phase in the very high H content region of the Pd-H system has been inferred on the basis of the determination of the temperature $9 coefficient of the electrical resistivity. For this purpose a thin layer of Hg was galvanic...

  17. Time and concentration dependency in the potentially affected fraction of species: the case of hydrogen peroxide treatment of ballast water.

    Science.gov (United States)

    Smit, Mathijs G D; Ebbens, Eltjo; Jak, Robbert G; Huijbregtst, Mark A J

    2008-03-01

    Transport of large volumes of ballast water contributes greatly to invasions of species. Hydrogen peroxide (H2O2) can be used as a disinfectant to prevent the spread of exotic species via ballast water. Instead of using environmental risk assessment techniques for protecting a certain fraction of the species from being affected, the present study aimed to apply these techniques to define treatment regimes of H2O2 and effectively eliminate as many species as possible. Based on time-dependent dose-response curves for five marine species (Corophium volutator, Artemia salina, Brachionus plicatilis, Dunaliella teriolecta, and Skeletonema costatum), time-dependent species-sensitivity distributions (SSDs) were derived for different effect sizes. The present study showed that H2O2 can be used effectively to treat ballast water but that relatively high concentrations and long treatment durations are required to eliminate the vast majority of species in ballast water. The described toxicant effectiveness approach using SSDs also has other potential fields of application, including short-term application of biocides.

  18. NIRS-Derived Tissue Oxygen Saturation and Hydrogen Ion Concentration Following Bed Rest

    Science.gov (United States)

    Lee, S. M. C.; Everett, M. E.; Crowell, J. B.; Westby, C. M.; Soller, B. R.

    2010-01-01

    Long-term bed rest (BR), a model of spaceflight, results in a decrease in aerobic capacity and altered submaximal exercise responses. The strongest BR-induced effects on exercise appear to be centrally-mediated, but longer BR durations may result in peripheral adaptations (e.g., decreased mitochondrial and capillary density) which are likely to influence exercise responses. PURPOSE: To measure tissue oxygen saturation (SO2) and hydrogen ion concentration ([H+]) in the vastus lateralis (VL) using near infrared spectroscopy (NIRS) during cycle ergometry before and after . 30 d of BR. METHODS: Eight subjects performed a graded exercise test on a cycle ergometer to volitional fatigue 7 d before (pre-BR) and at the end or 1 day after BR (post-BR). NIRS spectra were collected from a sensor adhered to the skin overlying the VL. Oxygen consumption (VO2) was measured by open circuit spirometry. Blood volume (BV) was measured before and after BR using the carbon monoxide rebreathing technique. Changes in pre- and post-BR SO2 and [H+] data were compared using mixed model analyses. BV and peak exercise data were compared using paired t-tests. RESULTS: BV (pre-BR: 4.3+/-0.3, post-BR: 3.7+/-0.2 L, mean+/-SE, p=.01) and peak VO2 (pre-BR: 1.98+/-0.24, post-BR: 1.48 +/-0.21 L/min, p<.01) were reduced after BR. As expected, SO2 decreased with exercise before and after BR. However, SO2 was lower post compared with pre-BR throughout exercise, including at peak exercise (pre-BR: 50+/-3, post-BR: 43+/-4%, p=.01). After BR, [H+] was higher at the start of exercise and did not increase at the same rate as pre-BR. Peak [H+] was not different from pre to post-BR (pre-BR: 36+/-2; post-BR: 38+/-2 nmol/L). CONCLUSIONS: Lower SO2 during exercise suggests that oxygen extraction in the VL is higher after BR, perhaps due to lower circulating blood volume. The higher [H+] after BR suggests a greater reliance upon glycolysis during submaximal exercise, although [H+] at peak exercise was unchanged

  19. High Temperature Vacuum Annealing and Hydrogenation Modification of Exfoliated Graphite Nanoplatelets

    Directory of Open Access Journals (Sweden)

    Xiaobing Li

    2013-01-01

    Full Text Available Highly active defect sites on the edges of graphene automatically capture oxygen from air to form various oxygen groups. A two-step procedure to remove various oxygen functional groups from the defect sites of exfoliated graphene nanoplatelets (GNPs has been developed to reduce the atomic oxygen concentration from 9.5% to 4.8%. This two-step approach involves high temperature vacuum annealing followed by hydrogenation to protect the reduced edge carbon atoms from recombining with the atmospheric oxygen. The reduced GNPs exhibit decreased surface resistance and graphitic potential-dependent capacitance characteristics compared to the complex potential-dependent capacitance characteristics exhibited by the unreduced GNPs as a result of the removal of the oxygen functional groups present primarily at the edges. These reduced GNPs also exhibit high electrochemical cyclic stability for electrochemical energy storage applications.

  20. High Performance, Low Cost Hydrogen Generation from Renewable Energy

    Energy Technology Data Exchange (ETDEWEB)

    Ayers, Katherine [Proton OnSite; Dalton, Luke [Proton OnSite; Roemer, Andy [Proton OnSite; Carter, Blake [Proton OnSite; Niedzwiecki, Mike [Proton OnSite; Manco, Judith [Proton OnSite; Anderson, Everett [Proton OnSite; Capuano, Chris [Proton OnSite; Wang, Chao-Yang [Penn State University; Zhao, Wei [Penn State University

    2014-02-05

    Renewable hydrogen from proton exchange membrane (PEM) electrolysis is gaining strong interest in Europe, especially in Germany where wind penetration is already at critical levels for grid stability. For this application as well as biogas conversion and vehicle fueling, megawatt (MW) scale electrolysis is required. Proton has established a technology roadmap to achieve the necessary cost reductions and manufacturing scale up to maintain U.S. competitiveness in these markets. This project represents a highly successful example of the potential for cost reduction in PEM electrolysis, and provides the initial stack design and manufacturing development for Proton’s MW scale product launch. The majority of the program focused on the bipolar assembly, from electrochemical modeling to subscale stack development through prototyping and manufacturing qualification for a large active area cell platform. Feasibility for an advanced membrane electrode assembly (MEA) with 50% reduction in catalyst loading was also demonstrated. Based on the progress in this program and other parallel efforts, H2A analysis shows the status of PEM electrolysis technology dropping below $3.50/kg production costs, exceeding the 2015 target.

  1. Investigation of bonded hydrogen defects in nanocrystalline diamond films grown with nitrogen/methane/hydrogen plasma at high power conditions

    Science.gov (United States)

    Tang, C. J.; Hou, Haihong; Fernandes, A. J. S.; Jiang, X. F.; Pinto, J. L.; Ye, H.

    2017-02-01

    In this work, we investigate the influence of some growth parameters such as high microwave power ranging from 3.0 to 4.0 kW and N2 additive on the incorporation of bonded hydrogen defects in nanocrystalline diamond (NCD) films grown through a small amount of pure N2 addition into conventional 4% CH4/H2 plasma using a 5 kW microwave plasma CVD system. Incorporation form and content of hydrogen point defects in the NCD films produced with pure N2 addition was analyzed by employing Fourier-transform infrared (FTIR) spectroscopy for the first time. A large amount of hydrogen related defects was detected in all the produced NCD films with N2 additive ranging from 29 to 87 μm thick with grain size from 47 nm to 31 nm. Furthermore, a specific new H related sharp absorption peak appears in all the NCD films grown with pure N2/CH4/H2 plasma at high powers and becomes stronger at powers higher than 3.0 kW and is even stronger than the 2920 cm-1 peak, which is commonly found in CVD diamond films. Based on these experimental findings, the role of high power and pure nitrogen addition on the growth of NCD films including hydrogen defect formation is analyzed and discussed.

  2. Experimental Demonstration of Advanced Palladium Membrane Separators for Central High Purity Hydrogen Production

    Energy Technology Data Exchange (ETDEWEB)

    Sean Emerson; Neal Magdefrau; Susanne Opalka; Ying She; Catherine Thibaud-Erkey; Thoman Vanderspurt; Rhonda Willigan

    2010-06-30

    The overall objectives for this project were to: (1) confirm the high stability and resistance of a PdCu trimetallic alloy to carbon and carbide formation and, in addition, resistance to sulfur, halides, and ammonia; (2) develop a sulfur, halide, and ammonia resistant alloy membrane with a projected hydrogen permeance of 25 m{sup 3}m{sup -2}atm{sup -0.5}h{sup -1} at 400 C and capable of operating at pressures of 12.1 MPa ({approx}120 atm, 1750 psia); and (3) construct and experimentally validate the performance of 0.1 kg/day H{sup 2} PdCu trimetallic alloy membrane separators at feed pressures of 2 MPa (290 psia) in the presence of H{sub 2}S, NH{sub 3}, and HCl. This project successfully increased the technology readiness level of palladium-based metallic membranes for hydrogen separation from coal-biomass gasifier exhaust or similar hydrogen-containing gas streams. The reversible tolerance of palladium-copper (PdCu) alloys was demonstrated for H{sub 2}S concentrations varying from 20 ppmv up to 487 ppmv and NH{sub 3} concentrations up to 9 ppmv. In addition, atomistic modeling validated the resistance of PdCu alloys to carbon formation, irreversible sulfur corrosion, and chlorine attack. The experimental program highlighted two key issues which must be addressed as part of future experimental programs: (1) tube defects and (2) non-membrane materials of construction. Four out of five FCC PdCu separators developed leaks during the course of the experimental program because {approx}10% of the alloy tubes contained a single defect that resulted in a thin, weak point in the tube walls. These defects limited operation of the existing tubes to less than 220 psig. For commercial applications of a PdCu alloy hydrogen separator under high sulfur concentrations, it was determined that stainless steel 316 is not suitable for housing or supporting the device. Testing with sulfur concentrations of 487 {+-} 4 ppmv resulted in severe corrosion of the stainless steel components of

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. High hydrogen production rate of microbial electrolysis cell (MEC) with reduced electrode spacing.

    Science.gov (United States)

    Cheng, Shaoan; Logan, Bruce E

    2011-02-01

    Practical applications of microbial electrolysis cells (MECs) require high hydrogen production rates and a compact reactor. These goals can be achieved by reducing electrode spacing but high surface area anodes are needed. The brush anode MEC with electrode spacing of 2 cm had a higher hydrogen production rate and energy efficiency than an MEC with a flat cathode and a 1-cm electrode spacing. The maximum hydrogen production rate with a 2 cm electrode spacing was 17.8 m(3)/m(3)d at an applied voltage of E(ap)=1 V. Reducing electrode spacing increased hydrogen production rates at the lower applied voltages, but not at the higher (>0.6 V) applied voltages. These results demonstrate that reducing electrode spacing can increase hydrogen production rate, but that the closest electrode spacing do not necessarily produce the highest possible hydrogen production rates. Copyright © 2010 Elsevier Ltd. All rights reserved.

  5. Polymeric hydrogen diffusion barrier, high-pressure storage tank so equipped, method of fabricating a storage tank and method of preventing hydrogen diffusion

    Science.gov (United States)

    Lessing, Paul A [Idaho Falls, ID

    2008-07-22

    An electrochemically active hydrogen diffusion barrier which comprises an anode layer, a cathode layer, and an intermediate electrolyte layer, which is conductive to protons and substantially impermeable to hydrogen. A catalytic metal present in or adjacent to the anode layer catalyzes an electrochemical reaction that converts any hydrogen that diffuses through the electrolyte layer to protons and electrons. The protons and electrons are transported to the cathode layer and reacted to form hydrogen. The hydrogen diffusion barrier is applied to a polymeric substrate used in a storage tank to store hydrogen under high pressure. A storage tank equipped with the electrochemically active hydrogen diffusion barrier, a method of fabricating the storage tank, and a method of preventing hydrogen from diffusing out of a storage tank are also disclosed.

  6. Polymeric hydrogen diffusion barrier, high-pressure storage tank so equipped, method of fabricating a storage tank and method of preventing hydrogen diffusion

    Science.gov (United States)

    Lessing, Paul A.

    2004-09-07

    An electrochemically active hydrogen diffusion barrier which comprises an anode layer, a cathode layer, and an intermediate electrolyte layer, which is conductive to protons and substantially impermeable to hydrogen. A catalytic metal present in or adjacent to the anode layer catalyzes an electrochemical reaction that converts any hydrogen that diffuses through the electrolyte layer to protons and electrons. The protons and electrons are transported to the cathode layer and reacted to form hydrogen. The hydrogen diffusion barrier is applied to a polymeric substrate used in a storage tank to store hydrogen under high pressure. A storage tank equipped with the electrochemically active hydrogen diffusion barrier, a method of fabricating the storage tank, and a method of preventing hydrogen from diffusing out of a storage tank are also disclosed.

  7. A titration method for determining individual oxidant concentration in the dual sodium persulfate and hydrogen peroxide oxidation system.

    Science.gov (United States)

    Liang, Chenju; He, Boyu

    2018-05-01

    The use of a dual oxidation system, which combines sodium persulfate (Na 2 S 2 O 8 , SPS) and hydrogen peroxide (H 2 O 2 , HP) is increasing as an in-situ chemical oxidation (ISCO) process for soil and groundwater remediation. An analytical method was assessed in this study for determining individual oxidant concentration in order to understand the interactions, and variations in the concentrations, of SPS and HP in aqueous systems containing both SPS and HP. The iodometric titration method was demonstrated to be capable of measuring total oxidant (SPS + HP) concentration; while the ceric sulfate titration method can be used specifically for measuring HP in the dual oxidation system without interfering with the iodometric titration. Therefore, SPS concentration can be deduced by subtraction of the HP concentration from the total oxidant concentration. Direct iodometric titration for determination of total oxidant at concentration above 20 mM exhibited <8% concentration. Based on the results of indirect determination of SPS in the dual oxidation system, an approximate 10% concentration variation was expected. This research may serve as a reference for measuring oxidant variations in this ISCO dual oxidant application. Copyright © 2018. Published by Elsevier Ltd.

  8. Hydrogen permeation behavior through F82H at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, S.; Katayama, K.; Shimozori, M.; Fukada, S. [Interdisciplinary Graduate School of Engineering Science, Kyushu University, Kyushu (Japan); Ushida, H. [Energy Science and Engineering, Faculty of Engineering, Kyushu University, Kyushu (Japan); Nishikawa, M. [Malaysia-Japan International Institute of Technology, UTM, Kuala Lumpur (Malaysia)

    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)

  9. Factors Impeding Enzymatic Wheat Gluten Hydrolysis at High Solid Concentrations

    NARCIS (Netherlands)

    Hardt, N.A.; Janssen, A.E.M.; Boom, R.M.; Goot, van der A.J.

    2014-01-01

    Enzymatic wheat gluten hydrolysis at high solid concentrations is advantageous from an environmental and economic point of view. However, increased wheat gluten concentrations result in a concentration effect with a decreased hydrolysis rate at constant enzyme-to-substrate ratios and a decreased

  10. [Effect of reduced oxygen concentrations and hydrogen sulfide on the amino acid metabolism and mesenchymal cells proliferation].

    Science.gov (United States)

    Plotnikova, L N; Berezovskii, V A; Veselskii, S P

    2015-01-01

    We investigated the effect of hydrogen sulfide donor (10(-12) mol/l NaHS--I group) alone and together with the reduced oxygen concentrations (5% O2--II group, 3% O2--III group, 24 h) on the biological processes of human stem cells culture. It was shown that the cells proliferation by the third day of cultivation in I, II and III group decreased 1,7; 2,8 and 4,2 times. On the 4th day of culture proliferation inhibited in I, II and III group by 29; 33 and 54% compared to the control. Thus, adverse effects NaHS enhanced by reducing the oxygen concentration. It was established that in all experimental versions rapidly absorbed from the culture medium amino acids: cysteine and cystine, serine and aspartic acid, valine and tryptophan, proline and hydroxyproline, which are involved in the synthesis of proteins, in particular collagen. In the culture medium increased the concentration of free amino acids of the three factions: arginine, histidine and taurine; glycine and methionine; alanine and glutamine. We believe that in the applied concentration of hydrogen sulfide donor in conditions of low oxygen in a gaseous medium incubation inhibits the proliferation and alters the amino acid metabolism of human cells line 4BL.

  11. Heterogeneous radiolysis of water: effect of the concentration of water in the adsorbed phase on the hydrogen yield

    Energy Technology Data Exchange (ETDEWEB)

    Garibov, A.A.; Gezalov, K.B.; Velibekova, G.Z.; Khudiev, A.T.; Ramazanova, M.K.; Kasumov, R.D.; Agaev, T.N.; Gasanov, A.M.

    1988-05-01

    A study was carried out on the effect of the water concentration on the molecular hydrogen yield during the heterogeneous radiolysis of water in the presence of KSK silica gel and NaX zeolite. The molecular hydrogen yield was found to rise with an increase in the degree of filling in the range /theta/ = 0-1, while the limiting values of G/sub total/(H/sub 2/) are reached in the region of unimolecular filling of the active centers. In order to clarify the mechanism of the heterogeneous radiolysis of water in the presence of zeolite systems, the ESR method was used to investigate the rate of accumulation of radiation defects in zeolite HLaY and also the water radiolysis process in its presence.

  12. Hydrogen separation by nanocrystalline titanium nitride membranes with high hydride ion conductivity

    Science.gov (United States)

    Kura, Chiharu; Kunisada, Yuji; Tsuji, Etsushi; Zhu, Chunyu; Habazaki, Hiroki; Nagata, Shinji; Müller, Michael P.; De Souza, Roger A.; Aoki, Yoshitaka

    2017-10-01

    The production of pure hydrogen for use in energy applications and related industries often relies on the permeation of hydrogen through palladium-based membranes. However, the scarcity of Pd reserves necessitates the development of affordable alternatives with high hydrogen permeability. Here we report room-temperature hydrogen permeability of titanium nitrides (widely used as tough and inert coating materials) enabled by mixed hydride ion-electron conductivity. Combined spectroscopic, permeability and microgravimetric measurements reveal that nanocrystalline TiNx membranes feature enhanced grain-boundary diffusion of hydride anions associated with interfacial Ti cations on nanograins. Since the corresponding activation energies are very low (kJ mol-1), these membranes yield a considerably higher room-temperature hydrogen flux than Pd membranes of equivalent thickness. Overall, the current study establishes general guidelines for developing hydride ion transport membranes based on a simple transition metal nitride for hydrogen purification, membrane reactors and other applications.

  13. Hydrogen uptake and diffusion in welds of high-strength steels; Wasserstoffaufnahme und -diffusion in Schweissnahtgefuegen hochfester Staehle

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, D.M.

    2005-07-01

    The mainly investigated supermartensitic stainless steels are experiencing first applications in the offshore technology as welded flowlines. These materials are intended to replace higher alloyed steels following the principle ''Fitness for Purpose''. These new types of steels are very suitable for those applications, because of their corrosion resistance and of their strength. But specially for the use under sour service conditions there exists the risk of hydrogen uptake with subsequent cracking. To evaluate the cracking resistance of the welds as well as of the unaffected material in the as-delivered condition, it is necessary to determine hydrogen transport data. Within the scope of this research project, such data are quantified in permeation experiments carried out on steel membranes under realistic application conditions. This procedure allows it to use the results in computer-assisted lifetime calculations. It was found that the diffusion coefficients of the respective materials and structures do not depend on the chemical composition of the electrolytic solution. By contrast, the subsurface concentration, i. e. the hydrogen concentration infiltrating into materials, depends on the pH-value, on the H{sub 2}S-saturation and on the composition of the electrolytic solution. The concentration of chloride ions was found to be the strongest factor of influence for the dependence of the subsurface concentration on the chemical composition of the electrolytic solution. In addition, a major influence of the chemical composition of supermartensitic steels on the permeation behaviour has been established. The comparison of the permeation behaviour between heat treated specimens and specimens with realistic weld microstructure revealed that especially the diffusion coefficients of the heat treated specimens increased by about ten times. This means that the hydrogen permeation behaviour in such joints must be determined separately in each individual

  14. Numerical Investigation of the Role of Volumetric Transformation Strain on the Relaxation Stress and the Corresponding Hydrogen Interstitial Concentration in Niobium Matrix

    Directory of Open Access Journals (Sweden)

    Burak Bal

    2017-01-01

    Full Text Available The effects of relaxation stress on the hydrogen concentration in Niobium- (Nb- H media were investigated by iterative numerical modeling approach. To calculate the transformation strain, relaxation stress, and corresponding relaxed hydrogen concentration around an edge dislocation, a new third-order polynomial formulation was utilized in the model. With the aid of this polynomial, hydrogen induced relaxation stress never exceeds the dislocation stress, which indicates that the total stress field never turns to compressive state and diverges the results. The current model calculates the hydrogen concentration not only in the vicinity of an edge dislocation but also far away from the dislocation. Furthermore, the effect of relaxation stress on the interaction energy was also captured in the model. Overall, the current findings shed light on the complicated hydrogen embrittlement mechanisms of metallic materials by demonstrating that hydrogen induced relaxation has a significant effect on the hydrogen atom concentration and the interaction energy between the existing internal stress field and the solute hydrogen atom.

  15. Specifics of high-temperature sodium coolant purification technology in fast reactors for hydrogen production and other innovative applications

    Directory of Open Access Journals (Sweden)

    F.A. Kozlov

    2017-03-01

    Full Text Available In creating a large-scale atomic-hydrogen power industry, the resolution of technological issues associated with high temperatures in reactor plants (900°C and large hydrogen concentrations intended as long-term resources takes on particular importance. The paper considers technological aspects of removing impurities from high-temperature sodium used as a coolant in the high-temperature fast reactor (BN-HT 600MW (th. intended for the production of hydrogen as well as other innovative applications. The authors examine the behavior of impurities in the BN-HT circuits associated with the mass transfer intensification at high temperatures (Arrhenius law in different operating modes. Special attention is given to sodium purification from hydrogen, tritium and corrosion products in the BN-HT. Sodium purification from hydrogen and tritium by their evacuation through vanadium or niobium membranes will make it possible to develop compact highly-efficient sodium purification systems. It has been shown that sodium purification from tritium to concentrations providing the maximum permissible concentration of the produced hydrogen (3.6Bq/l according to NRB-99/2009 specifies more stringent requirements to the hydrogen removal system, i.e., the permeability index of the secondary tritium removal system should exceed 140kg/s. Provided that a BN-HN-type reactor meets these conditions, the bulk of tritium (98% will be accumulated in the compact sodium purification system of the secondary circuit, 0.6% (∼ 4·104Bq/s, will be released into the environment and 1.3% will enter the product (hydrogen. The intensity of corrosion products (CPs coming into sodium is determined by the corrosion rate of structural materials: at a high temperature level, a significant amount of corrosion products flows into sodium. The performed calculations showed that, for the primary BN-HT circuit, the amount of corrosion products formed at the oxygen concentration in sodium of 1mln

  16. High Efficiency Solar Thermochemical Reactor for Hydrogen Production.

    Energy Technology Data Exchange (ETDEWEB)

    McDaniel, Anthony H. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2017-09-30

    This research and development project is focused on the advancement of a technology that produces hydrogen at a cost that is competitive with fossil-based fuels for transportation. A twostep, solar-driven WS thermochemical cycle is theoretically capable of achieving an STH conversion ratio that exceeds the DOE target of 26% at a scale large enough to support an industrialized economy [1]. The challenge is to transition this technology from the laboratory to the marketplace and produce hydrogen at a cost that meets or exceeds DOE targets.

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

    National Research Council Canada - National Science Library

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

    2013-01-01

    .... 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...

  18. Isothermal Microcalorimetric Evaluation of Compatibility of Proposed Injector Materials with High-Test Hydrogen Peroxide Propellant

    Science.gov (United States)

    Gostowski, Rudy

    2003-01-01

    High-test hydrogen peroxide (HTP) is receiving renewed interest as a monopropellant and as the oxidizer for bipropellant systems. HTP is hydrogen peroxide in concentrations ranging from 70 to 98%. All surfaces wetted by HTP must be evaluated for compatibility with the fluid. In the case of tanks, lines and valves compatibility is required to preserve the HTP oxygen and energy content and to avoid overpressurization due to decomposition. With injectors and regenerative cooling passages shorter exposure time reduces these concerns. However, phase changes from fluid to gas impact heat transfer and become the dominant compatibility concern. Isothermal microcalorimetry (IMC) provides a convenient and reproducible means to observe the decomposition of HTP when exposed to structural materials and therefore the compatibility of those materials'. The instrument provides heat flow values in terms of watts that may be converted to a reaction rate given the heat of reaction for the decomposition of hydrogen peroxide. These values are then converted to percent active oxygen loss per week (%AOL/wk) to preserve an earlier convention for quantifying HTP compatibility. Additionally, qualitative designations of compatibility have been assigned to these values. This scheme consists of four classes with Class 1 being the most compatible. While historical compatibility data is available its current applicability is in question due to subtle changes in the compositions of both HTP and structural materials. Trace levels of molecules can have significant influence on compatibility. Therefore representative samples of materials must be evaluated with current HTP formulations. In this work seven materials were selected for their strength characteristics at high temperature as expected in a HTP injector. The materials were then evaluated by IMC for HTP compatibility.

  19. High yields of hydrogen production from methanol steam reforming with a cross-U type reactor.

    Science.gov (United States)

    Zhang, Shubin; Zhang, Yufeng; Chen, Junyu; Zhang, Xuelin; Liu, Xiaowei

    2017-01-01

    This paper presents a numerical and experimental study on the performance of a methanol steam reformer integrated with a hydrogen/air combustion reactor for hydrogen production. A CFD-based 3D model with mass and momentum transport and temperature characteristics is established. The simulation results show that better performance is achieved in the cross-U type reactor compared to either a tubular reactor or a parallel-U type reactor because of more effective heat transfer characteristics. Furthermore, Cu-based micro reformers of both cross-U and parallel-U type reactors are designed, fabricated and tested for experimental validation. Under the same condition for reforming and combustion, the results demonstrate that higher methanol conversion is achievable in cross-U type reactor. However, it is also found in cross-U type reactor that methanol reforming selectivity is the lowest due to the decreased water gas shift reaction under high temperature, thereby carbon monoxide concentration is increased. Furthermore, the reformed gas generated from the reactors is fed into a high temperature proton exchange membrane fuel cell (PEMFC). In the test of discharging for 4 h, the fuel cell fed by cross-U type reactor exhibits the most stable performance.

  20. High yields of hydrogen production from methanol steam reforming with a cross-U type reactor.

    Directory of Open Access Journals (Sweden)

    Shubin Zhang

    Full Text Available This paper presents a numerical and experimental study on the performance of a methanol steam reformer integrated with a hydrogen/air combustion reactor for hydrogen production. A CFD-based 3D model with mass and momentum transport and temperature characteristics is established. The simulation results show that better performance is achieved in the cross-U type reactor compared to either a tubular reactor or a parallel-U type reactor because of more effective heat transfer characteristics. Furthermore, Cu-based micro reformers of both cross-U and parallel-U type reactors are designed, fabricated and tested for experimental validation. Under the same condition for reforming and combustion, the results demonstrate that higher methanol conversion is achievable in cross-U type reactor. However, it is also found in cross-U type reactor that methanol reforming selectivity is the lowest due to the decreased water gas shift reaction under high temperature, thereby carbon monoxide concentration is increased. Furthermore, the reformed gas generated from the reactors is fed into a high temperature proton exchange membrane fuel cell (PEMFC. In the test of discharging for 4 h, the fuel cell fed by cross-U type reactor exhibits the most stable performance.

  1. High yields of hydrogen production from methanol steam reforming with a cross-U type reactor

    Science.gov (United States)

    Zhang, Shubin; Chen, Junyu; Zhang, Xuelin; Liu, Xiaowei

    2017-01-01

    This paper presents a numerical and experimental study on the performance of a methanol steam reformer integrated with a hydrogen/air combustion reactor for hydrogen production. A CFD-based 3D model with mass and momentum transport and temperature characteristics is established. The simulation results show that better performance is achieved in the cross-U type reactor compared to either a tubular reactor or a parallel-U type reactor because of more effective heat transfer characteristics. Furthermore, Cu-based micro reformers of both cross-U and parallel-U type reactors are designed, fabricated and tested for experimental validation. Under the same condition for reforming and combustion, the results demonstrate that higher methanol conversion is achievable in cross-U type reactor. However, it is also found in cross-U type reactor that methanol reforming selectivity is the lowest due to the decreased water gas shift reaction under high temperature, thereby carbon monoxide concentration is increased. Furthermore, the reformed gas generated from the reactors is fed into a high temperature proton exchange membrane fuel cell (PEMFC). In the test of discharging for 4 h, the fuel cell fed by cross-U type reactor exhibits the most stable performance. PMID:29121067

  2. Sulfate and organic matter concentration in relation to hydrogen sulfide generation at inert solid waste landfill site - Limit value for gypsum.

    Science.gov (United States)

    Asakura, Hiroshi

    2015-09-01

    In order to suggest a limit value for gypsum (CaSO4) for the suppression of hydrogen sulfide (H2S) generation at an inert solid waste landfill site, the relationship between raw material (SO4 and organic matter) for H2S generation and generated H2S concentration, and the balance of raw material (SO4) and product (H2S) considering generation and outflow were investigated. SO4 concentration should be less than approximately 100mg-SO4/L in order to suppress H2S generation to below 2000ppm. Total organic carbon (TOC) concentration should be less than approximately 200mg-C/L assuming a high SO4 concentration. The limit value for SO4 in the ground is 60mg-SO4/kg with 0.011wt% as gypsum dihydrate, i.e., approximately 1/10 of the limit value in inert waste as defined by the EU Council Decision (560mg-SO4/kg-waste). The limit value for SO4 in inert waste as defined by the EU Council Decision is high and TOC is strictly excluded. The cumulative amount of SO4 outflow through the liquid phase is much larger than that through the gas phase. SO4 concentration in pore water decreases with time, reaching half the initial concentration around day 100. SO4 reduction by rainfall can be expected in the long term. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Effect of high pressure hydrogen on the mechanical characteristics of single carbon fiber

    Science.gov (United States)

    Jeon, Sang Koo; Kwon, Oh Heon; Jang, Hoon-Sik; Ryu, Kwon Sang; Nahm, Seung Hoon

    2018-02-01

    In this study, carbon fiber was exposed to a pressure of 7 MPa for 24 h in high pressure chamber. The tensile test for carbon fiber was conducted to estimate the effect on the high pressure hydrogen in the atmosphere. To determine the tensile strength and Weibull modulus, approximately thirty carbon fiber samples were measured in all cases, and carbon fiber exposed to high pressure argon was evaluated to verify only the effect of hydrogen. Additionally, carbon fiber samples were annealed at 1950 °C for 1 h for a comparison with normal carbon fiber and then tested under identical conditions. The results showed that the tensile strength scatter of normal carbon fiber exposed to hydrogen was relatively wider and the Weibull modulus was decreased. Moreover, the tensile strength of the annealed carbon fiber exposed to hydrogen was increased, and these samples indicated a complex Weibull modulus because the hydrogen stored in the carbon fiber influenced the mechanical characteristic.

  4. A new strategy to improve the high-rate performance of hydrogen storage alloys with MoS2 nanosheets

    Science.gov (United States)

    Chen, L. X.; Zhu, Y. F.; Yang, C. C.; Chen, Z. W.; Zhang, D. M.; Jiang, Q.

    2016-11-01

    The poor high-rate dischargeability of negative electrode materials (hydrogen storage alloys) has hindered applications of nickel metal hydride batteries in high-power fields, new-energy vehicles, power tools, military devices, etc. In this work, a new strategy is developed to improve the high-rate performance of hydrogen storage alloys by coating MoS2 nanosheets on alloy surfaces. The capacity retention rate of the composite electrode reaches 50.5% at a discharge current density of 3000 mA g-1, which is 2.7 times that of bare alloy (18.4%). The density functional theory simulations indicate that such an outstanding performance is derived from adjustments of ion concentrations at the electrode/electrolyte interface by MoS2 nanosheets: (1) the higher OH- concentration facilitates the electrochemical reaction of MHads + OH- - e- → M + H2O; and (2) the lower H+ concentration leads to a large gradient between the electrode/electrolyte interface and interior of alloys, which is beneficial for the diffusion of atomic hydrogen during the discharging process.

  5. A highly active cyclometallated iridium catalyst for the hydrogenation of imines.

    Science.gov (United States)

    Villa-Marcos, Barbara; Tang, Weijun; Wu, Xiaofeng; Xiao, Jianliang

    2013-09-25

    A cyclometallated iridium complex containing an imino ligand has been shown to catalyse the hydrogenation of imines. The catalyst is highly active and selective for imino bonds, with a wide variety of imines being hydrogenated in less than 1 hour at a substrate/catalyst (S/C) ratio of 2000 at 20 bar H2 pressure and 75 °C.

  6. Residual gas entering high density hydrogen plasma: rarefaction due to rapid heating

    NARCIS (Netherlands)

    N. den Harder,; D.C. Schram,; W. J. Goedheer,; de Blank, H. J.; M. C. M. van de Sanden,; van Rooij, G. J.

    2015-01-01

    The interaction of background molecular hydrogen with magnetized (0.4 T) high density (1–5 × 10 20  m −3 ) low temperature (∼3 eV) hydrogen plasma was inferred from the Fulcher band emission in the linear plasma generator Pilot-PSI. In the plasma center,

  7. Hydrogenated carbon clusters produced by highly charged ion impact on solid C-84

    NARCIS (Netherlands)

    Schlatholter, T; Newman, MW; Niedermayr, TR; Machicoane, GA; McDonald, JW; Schenkel, T; Hoekstra, R; Hamza, AV

    2000-01-01

    The emission of small (hydrogenated) carbon cluster ions: CnHm+ (n = 2-22) upon highly charged Xeq+ (q = 20- 14) impact on C-84 surfaces is studied by means of time-of-flight secundary ion mass spectrometry. The respective stage of hydrogenation/protonation of a certain carbon cluster ion C-n(+) is

  8. High Iridium concentration of alkaline rocks of Deccan and ...

    Indian Academy of Sciences (India)

    We report here an unusually high concentration of iridium in some alkali basalts and alkaline rocks of Deccan region having an age of about 65Ma, similar to the age of the Cretaceous-Tertiary boundary. The alkali basalts of Anjar, in the western periphery of Deccan province, have irid-ium concentration as high as 178pg/g ...

  9. Microsystem technology for high-flux hydrogen separation membranes

    NARCIS (Netherlands)

    Gielens, F.C.; Tong, D.H.; van Rijn, C.J.M.; Vorstman, M.A.G.; Keurentjes, J.T.F.

    2004-01-01

    The application of thin hydrogen-selective membranes suffers from the occurrence of pinholes and a significant resistance to mass transfer in the porous support. To overcome these problems, Pd, Pd/Ag and Pd–Ta–Pd membranes with a thickness between 0.5 and 1.2 μm have been deposited on a dense and

  10. In vitro evaluation of variances between real and declared concentration of hydrogen peroxide in various tooth-whitening products.

    Science.gov (United States)

    Majeed, Abdul; Farooq, Imran; Grobler, Sias R; Moola, M H

    2015-07-01

    The aim of this in vitro study was to analyze the real hydrogen peroxide (HP) concentration in various commercially available tooth-whitening products containing HP and/or carbamide peroxide (CP). Sixteen commercially available tooth-whitening products containing various concentrations of CP or HP were investigated. The products were divided into four groups: dentist-supervised home bleaching products (Group 1, n = 5), in-office bleaching products (Group 2, n = 4), over-the-counter bleaching products (Group 3, n = 3) and whitening toothpastes and rinses (Group 4, n = 4). The peroxide concentration was determined using the oxy-reduction titration method. All the reagents used in the study were of analytic grade and freshly prepared before the experiment. The HP concentration in various dentist-supervised home bleaching products and in-office bleaching products ranged from 3.02-37.08% (expected range = 3-38%). The HP concentration of over-the-counter whitening products ranged from 1.24-5.57% (expected range cannot be estimated as no concentration of active ingredient was provided). Among whitening toothpastes and rinses, Colgate Plax whitening rinse showed more than 1% HP concentration, whereas it was lower than 0.05% in other whitening toothpastes and oral rinses (expected range cannot be estimated as no active ingredient was mentioned). HP concentration of most of the professional tooth-whitening products was different from the expected concentrations, although the deviations were small and most of the products were close to the expected concentration. No concentration of active ingredient was provided for over-the-counter whitening products and no active ingredient was mentioned for whitening toothpastes and rinses.

  11. Effect of Hydrogen Concentration on the Growth of Carbon Nanotube Arrays for Gecko-Inspired Adhesive Applications

    Directory of Open Access Journals (Sweden)

    Yang Li

    2017-12-01

    Full Text Available Vertically-aligned carbon nanotubes (VACNTs have extraordinary structural and mechanical properties, and have been considered as potential candidates for creating dry adhesives inspired by adhesive structures in nature. Catalytic chemical vapor deposition is widely used to grow VACNTs; however, the influential mechanism of VACNT preparation parameters (such as H2 concentration on its adhesion property is not clear, making accurate control over the structure of VACNTs adhesive an ongoing challenge. In this article, we use electron beam-deposited SiO2/Al2O3 as a support layer, Fe as catalyst, and C2H4/H2 gas mixtures as a feed gas to prepare VACNTs, while varying the ratio of the reducing atmosphere (H2 from 0% to 35%. VACNTs synthesized at a 15% H2 concentration (5 mm × 5 mm in size can support a maximal weight of 856 g, which indicates a macroscopic shear adhesive strength of 34 N/cm2. We propose a hydrogen-concentration-dependent model for the shear adhesive performance of VACNTs. By adjusting the amount of hydrogen present during the reaction, the morphology and quality of the prepared VACNTs can be precisely controlled, which significantly influences its shear adhesive performance. These results are advantageous for the application of carbon nanotubes as dry adhesives.

  12. Reductimetric determination of peroxydisulphate, hydrogen peroxide, sodium perborate, nitrate and nitrite in concentrated phosphoric acid medium with iron(II).

    Science.gov (United States)

    Murty, N K; Satyanarayana, V; Rao, Y F

    1977-12-01

    A direct reductimetric method for the determination of peroxydisulphate, hydrogen peroxide, sodium perborate, nitrate and nitrite in fairly concentrated phosphoric acid medium with iron(II) has been developed, with both potentiometric and visual end-point detection. Cacotheline, Methylene Blue, thionine, Azure A, Azure B, Azure C, Toluidine Blue, new Methylene Blue, ferroin, N-phenylanthranilic acid, p-ethoxychrysoidine and barium diphenylaminesulphonate are used as indicators. The method is useful in the analysis of binary mixtures of peroxydisulphate and peroxide or perborate and in the estimation of the nitrate content of fertilizers.

  13. Microbial corrosion and cracking in steel. A concept for evaluation of hydrogen-assisted stress corrosion cracking in cathodically protected high-pressure gas transmission pipelines

    DEFF Research Database (Denmark)

    Nielsen, Lars Vendelbo

    An effort has been undertaken in order to develop a concept for evaluation of the risk of hydrogen-assisted cracking in cathodically protected gas transmission pipelines. The effort was divided into the following subtasks: A. Establish a correlation between the fracture mechanical properties...... of high-strength pipeline steel and the concentration of hydrogen present in the steel. B. Determine the degree hydrogen absorption by cathodically protected steel exposed in natural soil sediment, which include activity of sulphate-reducing bacteria (SRB). C. Compare the above points with fracture...

  14. Highly efficient hydrogen storage system based on ammonium bicarbonate/formate redox equilibrium over palladium nanocatalysts.

    Science.gov (United States)

    Su, Ji; Yang, Lisha; Lu, Mi; Lin, Hongfei

    2015-03-01

    A highly efficient, reversible hydrogen storage-evolution process has been developed based on the ammonium bicarbonate/formate redox equilibrium over the same carbon-supported palladium nanocatalyst. This heterogeneously catalyzed hydrogen storage system is comparable to the counterpart homogeneous systems and has shown fast reaction kinetics of both the hydrogenation of ammonium bicarbonate and the dehydrogenation of ammonium formate under mild operating conditions. By adjusting temperature and pressure, the extent of hydrogen storage and evolution can be well controlled in the same catalytic system. Moreover, the hydrogen storage system based on aqueous-phase ammonium formate is advantageous owing to its high volumetric energy density. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Simultaneous high-resolution measurement of mitochondrial respiration and hydrogen peroxide production.

    Science.gov (United States)

    Krumschnabel, Gerhard; Fontana-Ayoub, Mona; Sumbalova, Zuzana; Heidler, Juliana; Gauper, Kathrin; Fasching, Mario; Gnaiger, Erich

    2015-01-01

    Mitochondrial respiration is associated with the formation of reactive oxygen species, primarily in the form of superoxide (O2 (•-)) and particularly hydrogen peroxide (H2O2). Since H2O2 plays important roles in physiology and pathology, measurement of hydrogen peroxide has received considerable attention over many years. Here we describe how the well-established Amplex Red assay can be used to detect H2O2 production in combination with the simultaneous assessment of mitochondrial bioenergetics by high-resolution respirometry. Fundamental instrumental and methodological parameters were optimized for analysis of the effects of various substrate, uncoupler, and inhibitor titrations (SUIT) on respiration versus H2O2 production. The sensitivity of the H2O2 assay was strongly influenced by compounds contained in different mitochondrial respiration media, which also exerted significant effects on chemical background fluorescence changes. Near linearity of the fluorescence signal was restricted to narrow ranges of accumulating resorufin concentrations independent of the nature of mitochondrial respiration media. Finally, we show an application example using isolated mouse brain mitochondria as an experimental model for the simultaneous measurement of mitochondrial respiration and H2O2 production in SUIT protocols.

  16. Template electrodeposition of high-performance copper oxide nanosensors for electrochemical analysis of hydrogen peroxide.

    Science.gov (United States)

    Rajendra Kumar Reddy, Gajjala; Kumar, P Suresh

    2017-06-01

    We report on the facile electrodeposition of copper nanostructures on graphite lead substrate using anionic, cationic and non-ionic surfactant templates. Physical and electrochemical characterisation confirmed the influence of templates on the morphology and electrochemical catalytic activities of the copper electrodeposits. These electrodes were shown to be excellent electrocatalyst for the fast detection of hydrogen peroxide. A maximum sensitivity of 951.45μA/mM/cm2, LOD of 0.43μM, response time of <1s and a linearity in wide range of concentration from 1μM to 5mM were observed when sodium dodecyl sulfate was used as the template. While most of the previously reported sensors have advantages either on the facile synthesis or fast detection of analyte, our methodology enables preparation of the electrode within 120s and analysis within another 60s without any complicated procedure, thereby demonstrating one of the fastest and cost-effective method for hydrogen peroxide analysis with high sensitivity and selectivity. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Hydrogen production from high-moisture content biomass in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Antal, M.J. Jr.; Matsumura, Y.; Onuma, M.T. [Univ. of Hawaii, Honolulu, HI (United States)] [and others

    1995-09-01

    Wet biomass (water hyacinth, banana trees, cattails, green algae, kelp, etc.) grows rapidly and abundantly around the world. However, wet biomass is not regarded as a promising feedstock for conventional thermochemical conversion processes because the cost of drying the material is too high. Prior work has shown that low concentrations of glucose (a model compound for whole biomass) and various wet biomass species (water hyacinth, algae) can be completely gasified in supercritical water at 600{degrees}C and 34.5 MPa after a 30 s residence time. But higher concentrations of glucose evidenced incomplete conversion. For this reason, flow reactors were fabricated which could accommodate packed beds of catalyst, and studies were initiated of the steam reforming (gasification) reactions in the presence of various candidate heterogeneous catalysts. The goal is to identify active catalysts for steam reforming biomass slurries in supercritical water. Soon after tests began, a suitable class of carbon-based catalysts was discovered. These catalysts effect complete (>99%) conversion of high-concentration glucose (up to 22% by weight) to a hydrogen-rich synthesis gas. High space velocities are realized [>20 (g/hr)/g], and the catalyst is stable over a period of several hours. The carbon catalyst is not expensive, and exists in a wide variety of forms and compositions. After this discovery, work has focused on four interrelated tasks: (1) tests to identify the most active form and composition of the catalyst; (2) tests employing the preferred catalyst to study the effect of feedstock composition on carbon conversion and gas composition; (3) studies of catalyst deactivation and subsequent reactivation, including the in-house synthesis of bifunctional catalysts which incorporate promoters and stabilizers; and (4) the design and fabrication of a larger, new reactor with a slurry feeder intended to handle high-concentration, wet biomass feeds.

  18. Hydrogen gas filling into an actual tank at high pressure and optimization of its thermal characteristics

    Science.gov (United States)

    Khan, Md. Tawhidul Islam; Monde, Masanori; Setoguchi, Toshiaki

    2009-09-01

    Gas with high pressure is widely used at present as fuel storage mode for different hydrogen vehicles. Different types of materials are used for constructing these hydrogen pressure vessels. An aluminum lined vessel and typically carbon fiber reinforced plastic (CFRP) materials are commercially used in hydrogen vessels. An aluminum lined vessel is easy to construct and posses high thermal conductivity compared to other commercially available vessels. However, compared to CFRP lined vessel, it has low strength capacity and safety factors. Therefore, nowadays, CFRP lined vessels are becoming more popular in hydrogen vehicles. Moreover, CFRP lined vessel has an advantage of light weight. CFRP, although, has many desirable properties in reducing the weight and in increasing the strength, it is also necessary to keep the material temperature below 85 °C for maintaining stringent safety requirements. While filling process occurs, the temperature can be exceeded due to the compression works of the gas flow. Therefore, it is very important to optimize the hydrogen filling system to avoid the crossing of the critical limit of the temperature rise. Computer-aided simulation has been conducted to characterize the hydrogen filling to optimize the technique. Three types of hydrogen vessels with different volumes have been analyzed for optimizing the charging characteristics of hydrogen to test vessels. Gas temperatures are measured inside representative vessels in the supply reservoirs (H2 storages) and at the inlet to the test tank during filling.

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

    Energy Technology Data Exchange (ETDEWEB)

    James E. O& #39; 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.

  20. Selective carboxylate production by controlling hydrogen, carbon dioxide and substrate concentrations in mixed culture fermentation

    NARCIS (Netherlands)

    Arslan, D.; Steinbusch, K.J.J.; Diels, L.; Wever, de H.; Hamelers, H.V.M.; Buisman, C.J.N.

    2013-01-01

    This research demonstrated the selective production of n-butyrate from mixed culture by applying 2 bar carbon dioxide into the headspace of batch fermenters or by increasing the initial substrate concentration. The effect of increasing initial substrate concentration was investigated at 8, 13.5 and

  1. Discrimination of the oral microbiota associated with high hydrogen sulfide and methyl mercaptan production.

    Science.gov (United States)

    Takeshita, Toru; Suzuki, Nao; Nakano, Yoshio; Yasui, Masaki; Yoneda, Masahiro; Shimazaki, Yoshihiro; Hirofuji, Takao; Yamashita, Yoshihisa

    2012-01-01

    Both hydrogen sulfide (H2S) and methyl mercaptan (CH(3)SH) are frequently detected in large amounts in malodorous mouth air. We investigated the bacterial composition of saliva of 30 subjects with severe oral malodor exhibiting extreme CH(3)SH/H(2)S ratios (high H(2)S but low CH(3)SH concentrations, n 5 14; high CH(3)SH but low H2S concentrations, n 5 16) and 13 subjects without malodor, using barcoded pyrosequencing analysis of the 16S rRNA gene. Phylogenetic community analysis with the UniFrac distance metric revealed a distinct bacterial community structure in each malodor group. The H2S group showed higher proportions of the genera Neisseria, Fusobacterium, Porphyromonas and SR1 than the other two groups, whereas the CH(3)SH group had higher proportions of the genera Prevotella, Veillonella,Atopobium, Megasphaera, and Selenomonas. Our results suggested that distinct bacterial populations in the oral microbiota are involved in production of high levels of H2S and CH3SH in the oral cavity.

  2. High Efficiency Generation of Hydrogen Fuels Using Solar Thermochemical Splitting of Water

    Energy Technology Data Exchange (ETDEWEB)

    Heske, Clemens; Moujaes, Samir; Weimer, Alan; Wong, Bunsen; Siegal, Nathan; McFarland, Eric; Miller, Eric; Lewis, Michele; Bingham, Carl; Roth, Kurth; Sabacky, Bruce; Steinfeld, Aldo

    2011-09-29

    The objective of this work is to identify economically feasible concepts for the production of hydrogen from water using solar energy. The ultimate project objective was to select one or more competitive concepts for pilot-scale demonstration using concentrated solar energy. Results of pilot scale plant performance would be used as foundation for seeking public and private resources for full-scale plant development and testing. Economical success in this venture would afford the public with a renewable and limitless source of energy carrier for use in electric power load-leveling and as a carbon-free transportation fuel. The Solar Hydrogen Generation Research (SHGR) project embraces technologies relevant to hydrogen research under the Office of Hydrogen Fuel Cells and Infrastructure Technology (HFCIT) as well as concentrated solar power under the Office of Solar Energy Technologies (SET). Although the photoelectrochemical work is aligned with HFCIT, some of the technologies in this effort are also consistent with the skills and technologies found in concentrated solar power and photovoltaic technology under the Office of Solar Energy Technologies (SET). Hydrogen production by thermo-chemical water-splitting is a chemical process that accomplishes the decomposition of water into hydrogen and oxygen using only heat or a combination of heat and electrolysis instead of pure electrolysis and meets the goals for hydrogen production using only water and renewable solar energy as feed-stocks. Photoelectrochemical hydrogen production also meets these goals by implementing photo-electrolysis at the surface of a semiconductor in contact with an electrolyte with bias provided by a photovoltaic source. Here, water splitting is a photo-electrolytic process in which hydrogen is produced using only solar photons and water as feed-stocks. The thermochemical hydrogen task engendered formal collaborations among two universities, three national laboratories and two private sector

  3. Predicted effects of mineral neutralization and bisulfate formation on hydrogen ion concentration for dilute sulfuric acid pretreatment.

    Science.gov (United States)

    Lloyd, Todd A; Wyman, Charles E

    2004-01-01

    Dilute acid and water-only hemicellulose hydrolysis are being examined as part of a multiinstitutional cooperative effort to evaluate the performance of leading cellulosic biomass pretreatment technologies on a common basis. Cellulosic biomass, such as agricultural residues and forest wastes, can have a significant mineral content. It has been shown that these minerals neutralize some of the acid during dilute acid pretreatment, reducing its effectiveness, and the higher solids loadings desired to minimize costs will require increased acid use to compensate. However, for sulfuric acid in particular, an equilibrium shift to formation of bisulfate during neutralization can further reduce hydrogen ion concentrations and compound the effect of neutralization. Because the equilibrium shift has a more pronounced effect at lower acid concentrations, additional acid is needed to compensate. Coupled with the effect of temperature on acid dissociation, these effects increase acid requirements to achieve a particular reaction rate unless minerals are removed prior to hydrolysis.

  4. The Influence of Opacity on Hydrogen Line Emission and Ionisation Balance in High Density Divertor Plasmas

    OpenAIRE

    Behringer, K.

    1997-01-01

    The influence of opacity on hydrogen line emission and ionisation balance in high density divertor plasmas. - Garching bei München : Max-Planck-Inst. für Plasmaphysik, 1997. - 21 S. - (IPP-Report ; 10/5)

  5. The risk of hydrogen explosion in a submarine p. IV The implementation of high risk projects

    Directory of Open Access Journals (Sweden)

    Kłos Ryszard

    2017-06-01

    Full Text Available This series of articles on high risk projects looks at the example of the modernisation of hydrogen incinerators on a submarine. The article describes problems connected with the management of such a project.

  6. High hydrogen storage capacity of porous carbons prepared by using activated carbon.

    Science.gov (United States)

    Wang, Huanlei; Gao, Qiuming; Hu, Juan

    2009-05-27

    A kind of activated carbon with further carbon dioxide and potassium hydroxide activations for hydrogen storage was investigated. The carbon dioxide and potassium hydroxide activations have apparently different effects on the pore structures and textures of the activated carbon which closely associated with the hydrogen storage properties. The potassium hydroxide activation can remarkably donate microporosity to the frameworks of the activated carbon. One of the resultant porous carbons exhibited a high surface area of up to 3190 m(2) g(-1) and large gravimetric hydrogen uptake capacity of 7.08 wt % at 77 K and 20 bar, which is one of the largest data reported for the porous carbon materials. This result suggests that the porous carbon with large amounts of active sites, high surface area, and high micropore volume related to optimum pore size could achieve high gravimetric hydrogen storage.

  7. Placental weight in pregnancies with high or low hemoglobin concentrations.

    Science.gov (United States)

    Larsen, Sandra; Bjelland, Elisabeth Krefting; Haavaldsen, Camilla; Eskild, Anne

    2016-11-01

    To study the associations of maternal hemoglobin concentrations with placental weight and placental to birthweight ratio. In this retrospective cohort study, we included all singleton pregnancies during the years 1998-2013 at a large public hospital in Norway (n=57062). We compared mean placental weight and placental to birthweight ratio according to maternal hemoglobin concentrations: 13.5g/dl. The associations of maternal hemoglobin concentrations with placental weight and placental to birthweight ratio were estimated by linear regression analyses, and adjustments were made for gestational age at birth, preeclampsia, parity, maternal age, diabetes, body mass index, smoking, offspring sex and year of birth. In pregnancies with maternal hemoglobin concentrations hemoglobin concentrations 9-13.5g/dl and 655.5g (SD 147.7g) for hemoglobin concentrations >13.5g/dl (ANOVA, phemoglobin concentrations hemoglobin concentrations 9-13.5g/dl (0.193 (SD 0.040)) and >13.5g/dl (0.193 (SD 0.043)). Adjustments for our study factors did not alter the estimates notably. Placental weight decreased with increasing maternal hemoglobin concentrations. The high placental to birthweight ratio with low maternal hemoglobin concentrations suggests differences in placental growth relative to fetal growth across maternal hemoglobin concentrations. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Hydrogen production methods efficiency coupled to an advanced high temperature accelerator driven system

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez, Daniel González; Lira, Carlos Alberto Brayner de Oliveira [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Fernández, Carlos García, E-mail: danielgonro@gmail.com, E-mail: mmhamada@ipen.br [Instituto Superior de Tecnologías y Ciencias aplicadas (InSTEC), La Habana (Cuba)

    2017-07-01

    The hydrogen economy is one of the most promising concepts for the energy future. In this scenario, oil is replaced by hydrogen as an energy carrier. This hydrogen, rather than oil, must be produced in volumes not provided by the currently employed methods. In this work two high temperature hydrogen production methods coupled to an advanced nuclear system are presented. A new design of a pebbled-bed accelerator nuclear driven system called TADSEA is chosen because of the advantages it has in matters of transmutation and safety. For the conceptual design of the high temperature electrolysis process a detailed computational fluid dynamics model was developed to analyze the solid oxide electrolytic cell that has a huge influence on the process efficiency. A detailed flowsheet of the high temperature electrolysis process coupled to TADSEA through a Brayton gas cycle was developed using chemical process simulation software: Aspen HYSYS®. The model with optimized operating conditions produces 0.1627 kg/s of hydrogen, resulting in an overall process efficiency of 34.51%, a value in the range of results reported by other authors. A conceptual design of the iodine-sulfur thermochemical water splitting cycle was also developed. The overall efficiency of the process was calculated performing an energy balance resulting in 22.56%. The values of efficiency, hydrogen production rate and energy consumption of the proposed models are in the values considered acceptable in the hydrogen economy concept, being also compatible with the TADSEA design parameters. (author)

  9. High acrylate concentrations in the mucus of Phaeocystis globosa colonies

    NARCIS (Netherlands)

    Noordkamp, D.J B; Schotten, M; Gieskes, W.W C; Forney, L.J; Gottschal, J.C; van Rijssel, M

    1998-01-01

    Acrylate produced from dimethylsulphoniopropionate (DMSP) by Phaeocystis has been claimed to inhibit bacterial growth. However, the concentrations of acrylate measured in seawater during Phaeocystis blooms are not high enough to expect inhibition of bacterial growth. In this study, the total

  10. Chemical effects of a high CO2 concentration in oxy-fuel combustion of methane

    DEFF Research Database (Denmark)

    Glarborg, Peter; Bentzen, L.L.B.

    2008-01-01

    in terms of a detailed chemical kinetic mechanism for hydrocarbon oxidation. On the basis of results of the present study, it can be expected that oxy-fuel combustion will lead to strongly increased CO concentrations in the near-burner region. The CO2 present will compete with O-2 for atomic hydrogen...... CO2. The high local CO levels may have implications for near-burner corrosion and stagging, but increased problems with CO emission in oxy-fuel combustion are not anticipated....

  11. High performance hydrogen sensor based on Mn implanted ZnO nanowires array fabricated on ITO substrate.

    Science.gov (United States)

    Renitta, A; Vijayalakshmi, K

    2017-08-01

    In the present research, we propose a novel approach for the detection of hydrogen gas using Mn implanted ZnO nanowires fabricated onto ITO coated glass substrate by chemical spray pyrolysis deposition. The effect of Mn concentration on the structural, optical and morphological properties of ZnO films were investigated. X-ray diffraction studies showed that the Mn implanted ZnO films were grown as a polycrystalline hexagonal wurtzite phase without any impurities. The (101) peak position of ZnO-Mn films was shifted towards a lower angle with increasing Mn concentration. The optical band gap decreased from 3.45eV to 3.23eV with increasing Mn content. PL spectra, revealed sharp and strong near band edge emission which suggests that ZnO nanowires exhibit high crystalline quality. FE-SEM images of Mn implanted ZnO show perfectly aligned nanowires for all the films fabricated on ITO. The material (Zn, O, Mn) was confirmed by EDX spectra. The hydrogen sensing mechanism of the Mn implanted ZnO nanowire sensor was also discussed. It was found that H2 response was significantly enhanced by more than one order of magnitude with increasing Mn doping concentrations. The studied ZnO-Mn films coated on ITO substrate can be used as a low cost and easy-fabrication hydrogen sensing material. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Low concentrations of methamphetamine detectable in urine in the presence of high concentrations of amphetamine.

    Science.gov (United States)

    Jemionek, John F; Addison, Joseph; Past, Marilyn R

    2009-04-01

    Twenty-two urine specimens reported by military drug-testing laboratories for the presence of high concentrations of amphetamine only were subject to further analysis for the presence of methamphetamine. The 22 urine specimens had concentrations of amphetamine in the range of 28,028 to 241,142 ng/mL. The specimens were also assayed for the respective isomeric ratio of d (S) and l (R) amphetamine and methamphetamine. The results suggest that urine specimens containing high concentrations of amphetamine in which the urine concentration ratio of methamphetamine to amphetamine is less than 0.5% with similar isomeric distribution of d-(S) and l-(R) amphetamine and methamphetamine, respectively, may not necessarily indicate polydrug use.

  13. High concentration photovoltaic systems applying III-V cells

    Energy Technology Data Exchange (ETDEWEB)

    Zubi, Ghassan; Bernal-Agustin, Jose L. [Department of Electrical Engineering, University of Zaragoza, Calle Maria de Luna 3, 50018 Zaragoza (Spain); Fracastoro, Gian Vincenzo [Department of Energetics, Politecnico of Turin, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2009-12-15

    High concentration systems make use of the direct solar beam and therefore are suitable for application in regions with high annual direct irradiation values. III-V PV cells with a nominal efficiency of up to 39% are readily available in today's market, with further efficiency improvements expected in the years ahead. The relatively high cost of III-V cells limits their terrestrial use to applications under high concentration, usually above 400 suns. In this way the relatively high cell cost is compensated through the low amount for cells needed per kW nominal system output. This paper presents a state of the art of high concentration photovoltaics using III-V cells. This PV field accounts already for more than 20 developed systems, which are commercially available or shortly before market introduction. (author)

  14. Applications of nonimaging optics for very high solar concentrations

    Energy Technology Data Exchange (ETDEWEB)

    O`Gallagher, J.; Winston, R.

    1997-12-31

    Using the principles and techniques of nonimaging optics, solar concentrations that approach the theoretical maximum can be achieved. This has applications in solar energy collection wherever concentration is desired. In this paper, we survey recent progress in attaining and using high and ultrahigh solar fluxes. We review a number of potential applications for highly concentrated solar energy and the current status of the associated technology. By making possible new and unique applications for intense solar flux, these techniques have opened a whole new frontier for research and development of potentially economic uses of solar energy.

  15. Metallic WO2-Carbon Mesoporous Nanowires as Highly Efficient Electrocatalysts for Hydrogen Evolution Reaction.

    Science.gov (United States)

    Wu, Rui; Zhang, Jingfang; Shi, Yanmei; Liu, Dali; Zhang, Bin

    2015-06-10

    The development of electrocatalysts to generate hydrogen, with good activity and stability, is a great challenge in the fields of chemistry and energy. Here we demonstrate a "hitting three birds with one stone" method to synthesize less toxic metallic WO2-carbon mesoporous nanowires with high concentration of oxygen vacancies (OVs) via calcination of inorganic/organic WO3-ethylenediamine hybrid precursors. The products exhibit excellent performance for H2 generation: the onset overpotential is only 35 mV, the required overpotentials for 10 and 20 mA/cm(2) are 58 and 78 mV, the Tafel slope is 46 mV/decade, the exchange current density is 0.64 mA/cm(2), and the stability is over 10 h. Further studies, in combination with density functional theory, demonstrate that the unusual electronic structure and the large amount of active sites, generated by the high concentration of OVs, as well as the closely attached carbon materials, were key factors for excellent performance. Our results experimentally and theoretically establish metallic transition metal oxides (TMOs) as intriguing novel electrocatalysts for H2 generation. Such TMOs with OVs might be promising candidates for other energy storage and conversion applications.

  16. Zirconium-Based metal organic framework (Zr-MOF) material with high hydrostability for hydrogen storage applications

    CSIR Research Space (South Africa)

    Ren, Jianwei

    2013-09-01

    Full Text Available Material-based solutions, such as metal organic frameworks (MOFs), continue to attract increasing attention as viable options for hydrogen storage applications. MOFs are widely regarded as promising materials for hydrogen storage due to their high...

  17. Study of the high temperature characteristics of hydrogen storage alloys

    CERN Document Server

    Rong, Li; Shaoxiong, Zhou; Yan, Qi; 10.1016/j.jallcom.2004.07.006

    2005-01-01

    In this work, the phase structure of as-cast and melt-spun (MmY)/sub 1/(NiCoMnAl)/sub 5/ alloys (the content of yttrium is 0-2.5wt.%) and their electrochemical properties were studied with regard to discharge capacity at different temperatures (30-80 degrees C) and cycling life at 30 degrees C. It is found that the substitution of yttrium increase the electrochemical capacity of the compounds and decrease the difference in capacity between as-cast and as-quenched compounds at 30 degrees C. When increasing the yttrium concentration from 0 to 2.5wt.%, the cycling life of both the as-cast and the melt- spun compounds deteriorated, although the latter have a slightly longer cycle life than the former. The remarkable feature of the alloys obtained by yttrium substitution is the improvement of the high temperature electrochemical properties. It shows that the stability of the hydrides is increased. Compared with the as-cast alloys, the melt-spun ribbons have higher electrochemical charge /discharge capacity in the ...

  18. Hydrogen production from high moisture content biomass in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Antal, M.J. Jr.; Xu, X. [Univ. of Hawaii, Honolulu, HI (United States). Hawaii Natural Energy Inst.

    1998-08-01

    By mixing wood sawdust with a corn starch gel, a viscous paste can be produced that is easily delivered to a supercritical flow reactor by means of a cement pump. Mixtures of about 10 wt% wood sawdust with 3.65 wt% starch are employed in this work, which the authors estimate to cost about $0.043 per lb. Significant reductions in feed cost can be achieved by increasing the wood sawdust loading, but such an increase may require a more complex pump. When this feed is rapidly heated in a tubular flow reactor at pressures above the critical pressure of water (22 MPa), the sawdust paste vaporizes without the formation of char. A packed bed of carbon catalyst in the reactor operating at about 650 C causes the tarry vapors to react with water, producing hydrogen, carbon dioxide, and some methane with a trace of carbon monoxide. The temperature and history of the reactor`s wall influence the hydrogen-methane product equilibrium by catalyzing the methane steam reforming reaction. The water effluent from the reactor is clean. Other biomass feedstocks, such as the waste product of biodiesel production, behave similarly. Unfortunately, sewage sludge does not evidence favorable gasification characteristics and is not a promising feedstock for supercritical water gasification.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  20. Optimization and field demonstration of hybrid hydrogen generator/high efficiency furnace system

    Energy Technology Data Exchange (ETDEWEB)

    Entchev, E.; Coyle, I.; Szadkowski, F. [CANMET Energy Technology Centre, 1 Haanel Dr., Ottawa, Ontario K1A-1M1 (Canada); Manning, M.; Swinton, M. [National Research Council Ottawa, Ontario (Canada); Graydon, J.; Kirk, D. [University of Toronto, Toronto, Ontario (Canada)

    2009-05-15

    Hydrogen is seen as an energy carrier of the future and significant research on hydrogen generation, storage and utilization is accomplished around the world. However, an appropriate intermediate step before wide hydrogen introduction will be blending conventional fuels such as natural gas, oil or diesel with hydrogen and follow up combustion through conventional means. Due to changes in the combustion and flame characteristics of the system additional research is needed to access the limits and the impact of the fuel mix on the combustion systems performance. The hybrid system consists of a 5 kW{sub el} electrolyzer and a residential 15 kW{sub th} high efficiency gas fired furnace. The electrolyzer was integrated with the furnace gas supply and setup to replace 5-25% of the furnace natural gas flow with hydrogen. A mean for proper mixing of hydrogen with natural gas was provided and a control system for safe system operation was developed. Prior to the start of the field trial the hybrid system was investigated in laboratory environment. It was subjected to a variety of steady state and cycling conditions and a detailed performance and optimization analysis was performed with a range of hydrogen/natural gas mixtures. The optimized system was then installed at the Canadian Centre for Housing Technologies (CCHT) Experimental research house. The energy performance of the hybrid system was compared to the energy performance of an identical high efficiency furnace in the Control research house next door. (author)

  1. Synthesis of ceramic hollow fiber supported zeolitic imidazolate framework-8 (ZIF-8) membranes with high hydrogen permeability

    KAUST Repository

    Pan, Yichang

    2012-12-01

    Purification and recovery of hydrogen from hydrocarbons in refinery streams in the petrochemical industry is an emerging research field in the study of membrane gas separation. Hollow fiber membrane modules can be easily implemented into separation processes at the industrial scale. In this report, hollow yttria-stabilized zirconia (YSZ) fiber-supported zeolitic imidazole framework-8 (ZIF-8) membranes were successfully prepared using a mild and environmentally friendly seeded growth method. Our single-component permeation studies demonstrated that the membrane had a very high hydrogen permeance (~15×10 -7mol/m 2sPa) and an ideal selectivity of H 2/C 3H 8 of more than 1000 at room temperature. This high membrane permeability and selectivity caused serious concentration polarization in the separation of H 2/C 3H 8 mixtures, which led to almost 50% drop in both the H 2 permeance and the separation factor. Enhanced mixing on the feed side could reduce the effect of the concentration polarization. Our experimental data also indicated that the membranes had excellent reproducibility and long-term stability, indicating that the hollow fiber-supported ZIF-8 membranes developed in this study have great potential in industry-scale separation of hydrogen. © 2012 Elsevier B.V.

  2. Paracetamol (acetaminophen) decreases hydrogen sulfide tissue concentration in brain but increases it in the heart, liver and kidney in mice.

    Science.gov (United States)

    Wiliński, Bogdan; Wiliński, Jerzy; Somogyi, Eugeniusz; Góralska, Marta; Piotrowska, Joanna

    2011-01-01

    The biological action ofN-acetyl-p-aminophenol - paracetamol (acetaminophen) has been demonstrated to involve different mechanisms and is still not clear. Hydrogen sulfide (H2S) has been shown to play an important role in many physiological and pathological processes including nociception. The interaction between acetaminophen and endogenous H2S is unknown. Twenty four female CBA strain mice were administered intraperitoneal injections of N-acetyl-p-aminophenol solution: paracetemol in doses of 30 mg/kg b.w. per day (group D1, n = 8) or 100 mg/kg b.w. per day (group D2, n = 8).. The control group (n = 8) received physiological saline in portions of the same volume--0.2 ml. The measurements of tissue H2S concentration were performed with the Siegel spectrophotometric modified method. In the brain, the H2S tissue level decreased, but more significantly in the lower drug dose group. Conversely, there was a significant rise in the H2S tissue concentration in D1 and D2 groups in heart and kidney with the increase more pronounced in the group with the lower paracetamol dose. In the liver only the higher acetaminophen dose elicited a change in H2S concentration, increasing after administration of acetaminophen at 100 mg/kg. Our study demonstrates that paracetamol induces H2S tissue concentration changes in different mouse organs.

  3. A new concept for high-cycle-life LEO: Rechargeable MnO2-hydrogen

    Science.gov (United States)

    Appleby, A. J.; Dhar, H. P.; Kim, Y. J.; Murphy, O. J.

    1989-01-01

    The nickel-hydrogen secondary battery system, developed in the early 1970s, has become the system of choice for geostationary earth orbit (GEO) applications. However, for low earth orbit (LEO) satellites with long expected lifetimes the nickel positive limits performance. This requires derating of the cell to achieve very long cycle life. A new system, rechargeable MnO2-Hydrogen, which does not require derating, is described here. For LEO applications, it promises to have longer cycle life, high rate capability, a higher effective energy density, and much lower self-discharge behavior than those of the nickel-hydrogen system.

  4. Liquid Hydrogen Regulated Low Pressure High Flow Pneumatic Panel AFT Arrow Analysis

    Science.gov (United States)

    Jones, Kelley, M.

    2013-01-01

    Project Definition: Design a high flow pneumatic regulation panel to be used with helium and hydrogen. The panel will have two circuits, one for gaseous helium (GHe) supplied from the GHe Movable Storage Units (MSUs) and one for gaseous hydrogen (GH2) supplied from an existing GH2 Fill Panel. The helium will supply three legs; to existing panels and on the higher pressure leg and Simulated Flight Tanks (SFTs) for the lower pressure legs. The hydrogen line will pressurize a 33,000 gallon vacuum jacketed vessel.

  5. Differences in Swallowing between High and Low Concentration Taste Stimuli

    Directory of Open Access Journals (Sweden)

    Ahmed Nagy

    2014-01-01

    Full Text Available Taste is a property that is thought to potentially modulate swallowing behavior. Whether such effects depend on taste, intensity remains unclear. This study explored differences in the amplitudes of tongue-palate pressures in swallowing as a function of taste stimulus concentration. Tongue-palate pressures were collected in 80 healthy women, in two age groups (under 40, over 60, stratified by genetic taste status (nontasters, supertasters. Liquids with different taste qualities (sweet, sour, salty, and bitter were presented in high and low concentrations. General labeled magnitude scale ratings captured perceived taste intensity and liking/disliking of the test liquids. Path analysis explored whether factors of taste, concentration, age group, and/or genetic taste status impacted: (1 perceived intensity; (2 palatability; and (3 swallowing pressures. Higher ratings of perceived intensity were found in supertasters and with higher concentrations, which were more liked/disliked than lower concentrations. Sweet stimuli were more palatable than sour, salty, or bitter stimuli. Higher concentrations elicited stronger tongue-palate pressures independently and in association with intensity ratings. The perceived intensity of a taste stimulus varies as a function of stimulus concentration, taste quality, participant age, and genetic taste status and influences swallowing pressure amplitudes. High-concentration salty and sour stimuli elicit the greatest tongue-palate pressures.

  6. Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cells-update 2

    Science.gov (United States)

    Smithrick, John J.; Hall, Stephen W.

    An update of validation test results confirming the breakthrough in low earth orbit (LEO) cycle life of nickel-hydrogen cells containing 26 percent KOH electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel (IPV nickel-hydrogen cells has been previously reported. The cycle life of boiler plate cells containing 26 percent potassium hydroxide (KOH) electrolyte was about 40 000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH. This test was conducted at Hughes Aircraft Company under a NASA Lewis contract. The purpose was to investigate the effect of KOH concentration on cycle life. The cycle regime was a stressful accelerated LEO, which consisted of a 27.5 min charge followed by a 17.5 min discharge (2x normal rate). The depth of discharge (DOD) was 80 percent. The cell temperature was maintained at 23 C. The boiler plate test results are in the process of being validated using flight hardware and real time LEO test at the Naval Weapons Support Center (NWSC), Crane, Indiana under a NASA Lewis Contract. Six 48 Ah Hughes recirculation design IPV nickel-hydrogen flight battery cells are being evaluated. Three of the cells contain 26 percent KOH (test cells), and three contain 31 percent KOH (control cells). They are undergoing real time LEO cycle life testing. The cycle regime is a 90-min LEO orbit consisting of a 54-min charge followed by a 36-min discharge. The depth-of-discharge is 80 percent. The cell temperature is maintained at 10 C. The three 31 percent KOH cells failed (cycles 3729, 4165, and 11355). One of the 26 percent KOH cells failed at cycle 15314. The other two 26 percent KOH cells were cycled for over 16600 cycles during the continuing test.

  7. Turbulent Flame Propagation Characteristics of High Hydrogen Content Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Seitzman, Jerry [Georgia Inst. of Technology, Atlanta, GA (United States); Lieuwen, Timothy [Georgia Inst. of Technology, Atlanta, GA (United States)

    2014-09-30

    This final report describes the results of an effort to better understand turbulent flame propagation, especially at conditions relevant to gas turbines employing fuels with syngas or hydrogen mixtures. Turbulent flame speeds were measured for a variety of hydrogen/carbon monoxide (H2/CO) and hydrogen/methane (H2/CH4) fuel mixtures with air as the oxidizer. The measurements include global consumption speeds (ST,GC) acquired in a turbulent jet flame at pressures of 1-10 atm and local displacement speeds (ST,LD) acquired in a low-swirl burner at atmospheric pressure. The results verify the importance of fuel composition in determining turbulent flame speeds. For example, different fuel-air mixtures having the same unstretched laminar flame speed (SL,0) but different fuel compositions resulted in significantly different ST,GC for the same turbulence levels (u'). This demonstrates the weakness of turbulent flame speed correlations based simply on u'/SL,0. The results were analyzed using a steady-steady leading points concept to explain the sensitivity of turbulent burning rates to fuel (and oxidizer) composition. Leading point theories suggest that the premixed turbulent flame speed is controlled by the flame front characteristics at the flame brush leading edge, or, in other words, by the flamelets that advance farthest into the unburned mixture (the so-called leading points). For negative Markstein length mixtures, this is assumed to be close to the maximum stretched laminar flame speed (SL,max) for the given fuel-oxidizer mixture. For the ST,GC measurements, the data at a given pressure were well-correlated with an SL,max scaling. However the variation with pressure was not captured, which may be due to non-quasi-steady effects that are not included in the current model. For the ST,LD data, the leading points model again faithfully captured the variation of turbulent flame speed over a wide range of fuel-compositions and turbulence intensities. These

  8. High performance of hydrogen peroxide detection using Pt nanoparticles-dispersed carbon electrode prepared by pulsed arc plasma deposition.

    Science.gov (United States)

    Ito, Takeshi; Kunimatsu, Masayuki; Kaneko, Satoru; Hirabayashi, Yasuo; Soga, Masayasu; Agawa, Yoshiaki; Suzuki, Koji

    2012-09-15

    We propose novel electrodes with platinum nanoparticles dispersed on a glassy carbon (Pt-NPs/GC) prepared using a pulsed arc plasma deposition (APD) method. The method could coat Pt-NPs on a base material directly with a single-step process in a very short deposition time. The characteristics of the electrodes were discussed in detail. The detection of hydrogen peroxide was performed as an example for application of the electrodes. The distribution of nanoparticles was controlled easily by the number of pulse. The surface morphology changed with the pulse number and the annealing except for the sample prepared by 5 pulses deposition (APD(5)), implying that the APD(5) remained as NPs after the annealing. Average particle size was 2.7 nm on the Pt-NPs/GC. Catalyst activity for oxidizing hydrogen peroxide per Pt loading was excellent on the Pt-NPs/GC. When the Pt-NPs/GC was used as a detector for hydrogen peroxide on a flow injection analysis, the Pt-NPs/GC showed high sensitivity without deterioration. Oxidation current increased linearly with the concentration of hydrogen peroxide from 10nM to 100 μM. This fast and easily prepared electrode showed the capability to replace a conventional bulk metal electrode. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. An Experimental and Chemical Kinetics Study of the Combustion of Syngas and High Hydrogen Content Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, Robers [Pennsylvania State Univ., State College, PA (United States); Dryer, Frederick [Princeton Univ., NJ (United States); Ju, Yiguang [Princeton Univ., NJ (United States)

    2013-09-30

    An integrated and collaborative effort involving experiments and complementary chemical kinetic modeling investigated the effects of significant concentrations of water and CO2 and minor contaminant species (methane [CH4], ethane [C2H6], NOX, etc.) on the ignition and combustion of HHC fuels. The research effort specifically addressed broadening the experimental data base for ignition delay, burning rate, and oxidation kinetics at high pressures, and further refinement of chemical kinetic models so as to develop compositional specifications related to the above major and minor species. The foundation for the chemical kinetic modeling was the well validated mechanism for hydrogen and carbon monoxide developed over the last 25 years by Professor Frederick Dryer and his co-workers at Princeton University. This research furthered advance the understanding needed to develop practical guidelines for realistic composition limits and operating characteristics for HHC fuels. A suite of experiments was utilized that that involved a high-pressure laminar flow reactor, a pressure-release type high-pressure combustion chamber and a high-pressure turbulent flow reactor.

  10. Effect of ZDDP concentration on the thermal film formation on steel, hydrogenated non-doped and Si-doped DLC

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, S. [Laboratory for Tribology and Interface Nanotechnology, University of Ljubljana, Ljubljana (Slovenia); Kovač, J. [Jozef Stefan Institute, Jamova 19, 1000 Ljubljana (Slovenia); Kalin, M., E-mail: mitjan.kalin@tint.fs.uni-lj.si [Laboratory for Tribology and Interface Nanotechnology, University of Ljubljana, Ljubljana (Slovenia)

    2016-10-15

    Highlights: • The effect of the ZDDP concentrations onto the steel, H-DLC and Si-DLC surfaces is investigated. • ZDDP film structure on the DLC coatings is different from steel. • Different concentrations of ZDDP do not affect the final chemical structure of the ZDDP film on any of the studied surfaces. • The thickness of the thermal film is linear with the concentration for a given surface. • The reactivity of the ZDDP film is higher on the steel surface than on the DLC coatings. - Abstract: This work focuses on the ZDDP concentration (1, 5 and 20 wt%) to form a ZDDP film on surfaces during static thermal tests at 150 °C. Silicon-doped and hydrogenated DLC coatings, as well as steel as reference, were studied using Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The results show that, on the three surfaces, the structure of the ZDDP thermal film consists of identical groups of pyrophosphate and zinc oxide, while the sulphuric groups are dissimilar. On the steel surface, the sulphuric part consists of a mixture of organic sulphide and sulphohydryl groups, but on H-DLC and Si-DLC only organic sulphide groups are found; there are no sulphohydryl groups. Moreover, both ATR-FTIR and XPS show that different concentrations of ZDDP do not affect the final chemical structure of the ZDDP thermal film on any of the studied surfaces. In addition, the XPS results show that the thickness of the thermal film is linear with the concentration for the whole range from 1 to 20 wt%, supporting also its uniform chemical structure. These thicknesses further show that the reactivity of the ZDDP film is higher on the steel surface than on the DLC coatings.

  11. Quantum theoretical study of hydrogen under high pressure

    CERN Document Server

    Biermann, S

    2001-01-01

    In the first chapter we will review our knowledge of the phase diagram of hydrogen. Chapter 2 is a summary of the standard density functional and molecular dynamics methods and shows how these are combined in the Car-Parrinello method. Here the nuclei are still treated as classical particles obeying Newtonian mechanics. In chapter 3 we drop this approximation. The path integral description of quantum statistics is added on top of the classical Car-Parrinello method and yields a formalism that includes quantum effects due to the finite de Broglie wavelength of the nuclei. Some technical aspects, namely the parallel implementation of the Path Integral Car-Parrinello (PICP) method, are discussed in chapter 4. In chapter 5 we present the results of our PICP calculations and compare them with prior calculations using the classical Car-Parrinello method as described in chapter 2.

  12. High rates of catalytic hydrogen combustion with air over Ti ₀. ₉₇Pd ...

    Indian Academy of Sciences (India)

    High rates of catalytic hydrogen combustion with air over Ti ₀. ... For 50 mL of H ₂, it showed rates of the reaction around 36.45 μmol/g/s at room temperature and 230 μmol/g/s at 60◦C. It was found that the rate of reaction due ... Finally, we propose a mechanism of hydrogen and oxygen recombination reaction over Ti ₀.

  13. Single ZnO Nanowire-Based Gas Sensors to Detect Low Concentrations of Hydrogen

    Directory of Open Access Journals (Sweden)

    Marlene N. Cardoza-Contreras

    2015-12-01

    Full Text Available Low concentrations of hazardous gases are difficult to detect with common gas sensors. Using semiconductor nanostructures as a sensor element is an alternative. Single ZnO nanowire gas sensor devices were fabricated by manipulation and connection of a single nanowire into a four-electrode aluminum probe in situ in a dual-beam scanning electron microscope-focused ion beam with a manipulator and a gas injection system in/column. The electrical response of the manufactured devices shows response times up to 29 s for a 121 ppm of H2 pulse, with a variation in the nanowire resistance appreciable at room temperature and at 373.15 K of approximately 8% and 14% respectively, showing that ZnO nanowires are good candidates to detect low concentrations of H2.

  14. Method of monitoring CO concentrations in hydrogen feed to a PEM fuel cell

    Science.gov (United States)

    Grot, Stephen Andreas; Meltser, Mark Alexander; Gutowski, Stanley; Neutzler, Jay Kevin; Borup, Rodney Lynn; Weisbrod, Kirk

    2000-01-01

    The CO concentration in the H.sub.2 feed stream to a PEM fuel cell stack is monitored by measuring current and/or voltage behavior patterns from a PEM-probe communicating with the reformate feed stream. Pattern recognition software may be used to compare the current and voltage patterns from the PEM-probe to current and voltage telltale outputs determined from a reference cell similar to the PEM-probe and operated under controlled conditions over a wide range of CO concentrations in the H.sub.2 fuel stream. The PEM-probe is intermittently purged of any CO build-up on the anode catalyst (e.g., by (1) flushing the anode with air, (2) short circuiting the PEM-probe, or (3) reverse biasing the PEM-probe) to keep the PEM-probe at peak performance levels.

  15. Outdoor Characterisation of High Efficiency Luminescent Solar Concentrators

    OpenAIRE

    PRAVETTONI Mauro; VIRTUANI Alessandro; Kenny, Robert; Daniel J. Farrell; Chatten, Amanda J.; Barnham, Keith W J

    2008-01-01

    This work presents recent results on outdoor characterisation of high efficiency luminescent solar concentrators. Outdoor measurements at 25°C and corrected to 1000 W/m2 have been compared with indoor characterization according to the international standards for conventional photovoltaic devices. Dependence of electrical parameters with temperature is also shown, together with results of various 1-day monitoring campaigns of luminescent concentrators performance under varying irradiance condi...

  16. Analysis of the Hydrogen Reduction Rate of Magnetite Concentrate Particles in a Drop Tube Reactor Through CFD Modeling

    Science.gov (United States)

    Fan, Deqiu; Mohassab, Yousef; Elzohiery, Mohamed; Sohn, H. Y.

    2016-06-01

    A computational fluid dynamics (CFD) approach, coupled with experimental results, was developed to accurately evaluate the kinetic parameters of iron oxide particle reduction. Hydrogen reduction of magnetite concentrate particles was used as a sample case. A detailed evaluation of the particle residence time and temperature profile inside the reactor is presented. This approach eliminates the errors associated with assumptions like constant particle temperature and velocity while the particles travel down a drop tube reactor. The gas phase was treated as a continuum in the Eulerian frame of reference, and the particles are tracked using a Lagrangian approach in which the trajectory and velocity are determined by integrating the equation of particle motion. In addition, a heat balance on the particle that relates the particle temperature to convection and radiation was also applied. An iterative algorithm that numerically solves the governing coupled ordinary differential equations was developed to determine the pre-exponential factor and activation energy that best fit the experimental data.

  17. A first principles analysis of the effect of hydrogen concentration in hydrogenated amorphous silicon on the formation of strained Si-Si bonds and the optical and mobility gaps

    Energy Technology Data Exchange (ETDEWEB)

    Legesse, Merid; Nolan, Michael, E-mail: Michael.nolan@tyndall.ie; Fagas, Giorgos, E-mail: Georgios.fagas@tyndall.ie [Tyndall National Institute, University College Cork, Lee Maltings, Dyke Parade, Cork (Ireland)

    2014-05-28

    In this paper, we use a model of hydrogenated amorphous silicon generated from molecular dynamics with density functional theory calculations to examine how the atomic geometry and the optical and mobility gaps are influenced by mild hydrogen oversaturation. The optical and mobility gaps show a volcano curve as the hydrogen content varies from undersaturation to mild oversaturation, with largest gaps obtained at the saturation hydrogen concentration. At the same time, mid-gap states associated with dangling bonds and strained Si-Si bonds disappear at saturation but reappear at mild oversaturation, which is consistent with the evolution of optical gap. The distribution of Si-Si bond distances provides the key to the change in electronic properties. In the undersaturation regime, the new electronic states in the gap arise from the presence of dangling bonds and strained Si-Si bonds, which are longer than the equilibrium Si-Si distance. Increasing hydrogen concentration up to saturation reduces the strained bonds and removes dangling bonds. In the case of mild oversaturation, the mid-gap states arise exclusively from an increase in the density of strained Si-Si bonds. Analysis of our structure shows that the extra hydrogen atoms form a bridge between neighbouring silicon atoms, thus increasing the Si-Si distance and increasing disorder in the sample.

  18. Experimental evidence for a lack of thermodynamic control on hydrogen concentrations during anaerobic degradation of chlorinated ethenes.

    Science.gov (United States)

    Heimann, Axel C; Jakobsen, Rasmus

    2006-06-01

    Hydrogen (H2) concentrations during reductive dechlorination of cis-dichloroethene (cDCE) and vinyl chloride (VC) were investigated with respectto the influence of parameters entering the Gibbs free energy expression of the reactions. A series of laboratory experiments was conducted employing a mixed, Dehalococcoides-containing enrichment culture capable of complete dechlorination of chlorinated ethenes. The objective was to investigate whether a constant energy gain controls H2 levels in dechlorinating systems, thereby evaluating the applicability of the partial equilibrium approach to microbial dechlorination at contaminated sites. Variations in the temperature between 10 and 30 degrees C did not affect the H2 concentration in a fashion that suggested thermodynamic control through a constant energy gain. In another set of experiments, H2 levels at constant ionic strength were independent of the chloride concentration between 10 and 110 mmol chloride per liter. These findings demonstrate that the partial equilibrium approach is not directly applicable to the interpretation of reductive degradation of chlorinated ethenes. We also present recalculated thermodynamic properties of aqueous chlorinated ethene species that allow for calculation of in-situ Gibbs free energy of dechlorination reactions at different temperatures.

  19. Self-optimizing, highly surface-active layered metal dichalcogenide catalysts for hydrogen evolution

    Science.gov (United States)

    Liu, Yuanyue; Wu, Jingjie; Hackenberg, Ken P.; Zhang, Jing; Wang, Y. Morris; Yang, Yingchao; Keyshar, Kunttal; Gu, Jing; Ogitsu, Tadashi; Vajtai, Robert; Lou, Jun; Ajayan, Pulickel M.; Wood, Brandon C.; Yakobson, Boris I.

    2017-09-01

    Low-cost, layered transition-metal dichalcogenides (MX2) based on molybdenum and tungsten have attracted substantial interest as alternative catalysts for the hydrogen evolution reaction (HER). These materials have high intrinsic per-site HER activity; however, a significant challenge is the limited density of active sites, which are concentrated at the layer edges. Here we unravel electronic factors underlying catalytic activity on MX2 surfaces, and leverage the understanding to report group-5 MX2 (H-TaS2 and H-NbS2) electrocatalysts whose performance instead mainly derives from highly active basal-plane sites, as suggested by our first-principles calculations and performance comparisons with edge-active counterparts. Beyond high catalytic activity, they are found to exhibit an unusual ability to optimize their morphology for enhanced charge transfer and accessibility of active sites as the HER proceeds, offering a practical advantage for scalable processing. The catalysts reach 10 mA cm-2 current density at an overpotential of ˜50-60 mV with a loading of 10-55 μg cm-2, surpassing other reported MX2 candidates without any performance-enhancing additives.

  20. Microstructure and mechanical property performance of commercial grade API pipeline steels in high pressure gaseous hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Stalheim, Douglas G. [DGS Metallurgical Solutions, Inc., Vancouver, WA, (United States); Boggess, Todd [Secat Inc., Lexington, KY, (United States); San Marchi, Chris; Somerday, Brian [Sandia National Laboratory, Livermore, CA, (United States); Jansto, Steve [Reference Metals Company, Bridgeville, PA, (United States); Muralidharan, Govindarajan [Oak Ridge National Laboratory, Oak Ridge, TN, (United States)

    2010-07-01

    The transportation of hydrogen by pipeline steels raises questions of the degradation of the mechanical properties of the steel. This study investigated the microstructure and mechanical property performance of pipeline steels in high pressure gaseous hydrogen. The performance of four commercially available pipeline steels have been tested in the presence of pressurized hydrogen gas at different pressures in the range of 5.5 MPa and 20.7 MPa. Microstructural characterizations, tensile testing, fracture testing and fatigue testing have been performed for each alloy. The results showed that the four pipeline steels perform differently in gaseous hydrogen. Yield strength does not seem to have a relevant effect on performance, which highlights the importance of the microstructure in determining the resistance of pipeline steels. Of the four microstructures, the polygonal ferrite/10% coarse acicular ferrite microstructure gave the best performance.

  1. DETERMINATION OF HYDROGEN DESORBED THROUGH THERMAL CALORIMETRY IN A HIGH STRENGTH STEEL

    Directory of Open Access Journals (Sweden)

    Carolina A. Asmus

    2014-03-01

    Full Text Available The following study aims to quantify the release activation energy (Ea of hydrogen (H from lattice sites, reversible or irreversible, where the H can be trapped. Moreover, enthalpy changes associated with the main hydrogen (H trapping sites can be analyzed by means of differential scanning calorimetry (DSC. In this technique, the peak temperature measurement is determined at two different heating rates, 3ºC/min y 5ºC/min, from ambient temperature to 500°C. In order to simulate severe conditions of hydrogen income into resulfurized high strength steel, electrolytic permeation tests were performed on test tubes suitable for fatigue tests. Sometimes during charging, H promoters were aggregated to electrolytic solution. Subsequently, the test tubes were subjected to flow cycle fatigue tests. Finally, irreversible trap which anchor more strongly H atoms are MnS inclusions. Its role on hydrogen embrittlement during fatigue tests is conclusive.

  2. High Density Hydrogen Storage System Demonstration Using NaAlH4 Based Complex Compound Hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Daniel A. Mosher; Xia Tang; Ronald J. Brown; Sarah Arsenault; Salvatore Saitta; Bruce L. Laube; Robert H. Dold; Donald L. Anton

    2007-07-27

    This final report describes the motivations, activities and results of the hydrogen storage independent project "High Density Hydrogen Storage System Demonstration Using NaAlH4 Based Complex Compound Hydrides" performed by the United Technologies Research Center under the Department of Energy Hydrogen Program, contract # DE-FC36-02AL67610. The objectives of the project were to identify and address the key systems technologies associated with applying complex hydride materials, particularly ones which differ from those for conventional metal hydride based storage. This involved the design, fabrication and testing of two prototype systems based on the hydrogen storage material NaAlH4. Safety testing, catalysis studies, heat exchanger optimization, reaction kinetics modeling, thermochemical finite element analysis, powder densification development and material neutralization were elements included in the effort.

  3. Tank designs for combined high pressure gas and solid state hydrogen storage

    DEFF Research Database (Denmark)

    Mazzucco, Andrea

    Many challenges have still to be overcome in order to establish a solid ground for significant market penetration of fuel cell hydrogen vehicles. The development of an effective solution for on-board hydrogen storage is one of the main technical tasks that need to be tackled. The present thesis...... for each storage solution investigated in this work. Attention is given to solutions that involve high-pressure solid-state and gas hydrogen storage with an integrated passive cooling system. A set of libraries is implemented in the modeling platform to select among different material compositions, kinetic...... compressed-hydrogen vessel respectively. For the former, these models are used to quantify the main design parameter, being the critical metal hydride thickness, for the tank/heat-exchanger system. For the metal hydride tank, the tubular layout in a shell and tube configuration with 2 mm inner diameter tubes...

  4. The Role of κ-Carbides as Hydrogen Traps in High-Mn Steels

    Directory of Open Access Journals (Sweden)

    Tobias A. Timmerscheidt

    2017-07-01

    Full Text Available Since the addition of Al to high-Mn steels is known to reduce their sensitivity to hydrogen-induced delayed fracture, we investigate possible trapping effects connected to the presence of Al in the grain interior employing density-functional theory (DFT. The role of Al-based precipitates is also investigated to understand the relevance of short-range ordering effects. So-called E21-Fe3AlC κ-carbides are frequently observed in Fe-Mn-Al-C alloys. Since H tends to occupy the same positions as C in these precipitates, the interaction and competition between both interstitials is also investigated via DFT-based simulations. While the individual H–H/C–H chemical interactions are generally repulsive, the tendency of interstitials to increase the lattice parameter can yield a net increase of the trapping capability. An increased Mn content is shown to enhance H trapping due to attractive short-range interactions. Favorable short-range ordering is expected to occur at the interface between an Fe matrix and the E21-Fe3AlC κ-carbides, which is identified as a particularly attractive trapping site for H. At the same time, accumulation of H at sites of this type is observed to yield decohesion of this interface, thereby promoting fracture formation. The interplay of these effects, evident in the trapping energies at various locations and dependent on the H concentration, can be expressed mathematically, resulting in a term that describes the hydrogen embrittlement.

  5. Sterile Filtration of Highly Concentrated Protein Formulations: Impact of Protein Concentration, Formulation Composition, and Filter Material.

    Science.gov (United States)

    Allmendinger, Andrea; Mueller, Robert; Huwyler, Joerg; Mahler, Hanns-Christian; Fischer, Stefan

    2015-10-01

    Differences in filtration behavior of concentrated protein formulations were observed during aseptic drug product manufacturing of biologics dependent on formulation composition. The present study investigates filtration forces of monoclonal antibody formulations in a small-scale set-up using polyvinylidene difluoride (PVDF) or polyethersulfone (PES) filters. Different factors like formulation composition and protein concentration related to differences in viscosity, as well as different filtration rates were evaluated. The present study showed that filtration behavior was influenced by the presence or absence of a surfactant in the formulation, which defines the interaction between filter membrane and surface active formulation components. This can lead to a change in filter resistance (PES filter) independent on the buffer system used. Filtration behavior was additionally defined by rheological non-Newtonian flow behavior. The data showed that high shear rates resulting from small pore sizes and filtration pressure up to 1.0 bar led to shear-thinning behavior for highly concentrated protein formulations. Differences in non-Newtonian behavior were attributed to ionic strength related to differences in repulsive and attractive interactions. The present study showed that the interplay of formulation composition, filter material, and filtration rate can explain differences in filtration behavior/filtration flux observed for highly concentrated protein formulations thus guiding filter selection. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  6. Denitrification of fertilizer wastewater at high chloride concentration

    DEFF Research Database (Denmark)

    Ucisik, Ahmed Süheyl; Henze, Mogens

    Wastewater from fertilizer industry is characterized by high contents of chloride concentration, which normally vary between 60 and 76 g/l. Experiments with bilogical denitrification were performed in lab-scale "fill and draw" reactors with synthetic wastewater with chloride concentrations up to 77.......4 g/l. The results of the experiments showed that biological denitrification was feasible at the extreme environmental conditions prevailing in fertilizer wastewater. Stable continuous biological denitrfication of the synthetic high chloride wastewater was performed up to 77.4 g Cl/l at 37 degree C...

  7. Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.

    Energy Technology Data Exchange (ETDEWEB)

    Dadfarnia, Mohsen (University of Illinois at Urbana-Champaign, Urbana, IL); Nibur, Kevin A.; San Marchi, Christopher W.; Sofronis, Petros (University of Illinois at Urbana-Champaign, Urbana, IL); Somerday, Brian P.; Foulk, James W., III; Hayden, Gary A. (CP Industries, McKeesport, PA)

    2010-07-01

    Threshold stress intensity factors were measured in high-pressure hydrogen gas for a variety of low alloy ferritic steels using both constant crack opening displacement and rising crack opening displacement procedures. The sustained load cracking procedures are generally consistent with those in ASME Article KD-10 of Section VIII Division 3 of the Boiler and Pressure Vessel Code, which was recently published to guide design of high-pressure hydrogen vessels. Three definitions of threshold were established for the two test methods: K{sub THi}* is the maximum applied stress intensity factor for which no crack extension was observed under constant displacement; K{sub THa} is the stress intensity factor at the arrest position for a crack that extended under constant displacement; and K{sub JH} is the stress intensity factor at the onset of crack extension under rising displacement. The apparent crack initiation threshold under constant displacement, K{sub THi}*, and the crack arrest threshold, K{sub THa}, were both found to be non-conservative due to the hydrogen exposure and crack-tip deformation histories associated with typical procedures for sustained-load cracking tests under constant displacement. In contrast, K{sub JH}, which is measured under concurrent rising displacement and hydrogen gas exposure, provides a more conservative hydrogen-assisted fracture threshold that is relevant to structural components in which sub-critical crack extension is driven by internal hydrogen gas pressure.

  8. High capacity hydrogen storage materials: attributes for automotive applications and techniques for materials discovery.

    Science.gov (United States)

    Yang, Jun; Sudik, Andrea; Wolverton, Christopher; Siegel, Donald J

    2010-02-01

    Widespread adoption of hydrogen as a vehicular fuel depends critically upon the ability to store hydrogen on-board at high volumetric and gravimetric densities, as well as on the ability to extract/insert it at sufficiently rapid rates. As current storage methods based on physical means--high-pressure gas or (cryogenic) liquefaction--are unlikely to satisfy targets for performance and cost, a global research effort focusing on the development of chemical means for storing hydrogen in condensed phases has recently emerged. At present, no known material exhibits a combination of properties that would enable high-volume automotive applications. Thus new materials with improved performance, or new approaches to the synthesis and/or processing of existing materials, are highly desirable. In this critical review we provide a practical introduction to the field of hydrogen storage materials research, with an emphasis on (i) the properties necessary for a viable storage material, (ii) the computational and experimental techniques commonly employed in determining these attributes, and (iii) the classes of materials being pursued as candidate storage compounds. Starting from the general requirements of a fuel cell vehicle, we summarize how these requirements translate into desired characteristics for the hydrogen storage material. Key amongst these are: (a) high gravimetric and volumetric hydrogen density, (b) thermodynamics that allow for reversible hydrogen uptake/release under near-ambient conditions, and (c) fast reaction kinetics. To further illustrate these attributes, the four major classes of candidate storage materials--conventional metal hydrides, chemical hydrides, complex hydrides, and sorbent systems--are introduced and their respective performance and prospects for improvement in each of these areas is discussed. Finally, we review the most valuable experimental and computational techniques for determining these attributes, highlighting how an approach that

  9. Shifts in Rumen Fermentation and Microbiota Are Associated with Dissolved Ruminal Hydrogen Concentrations in Lactating Dairy Cows Fed Different Types of Carbohydrates.

    Science.gov (United States)

    Wang, Min; Wang, Rong; Xie, Tian Yu; Janssen, Peter H; Sun, Xue Zhao; Beauchemin, Karen A; Tan, Zhi Liang; Gao, Min

    2016-09-01

    Different carbohydrates ingested greatly influence rumen fermentation and microbiota and gaseous methane emissions. Dissolved hydrogen concentration is related to rumen fermentation and methane production. We tested the hypothesis that carbohydrates ingested greatly alter the rumen environment in dairy cows, and that dissolved hydrogen concentration is associated with these changes in rumen fermentation and microbiota. Twenty-eight lactating Chinese Holstein dairy cows [aged 4-5 y, body weight 480 ± 37 kg (mean ± SD)] were used in a randomized complete block design to investigate effects of 4 diets differing in forage content (45% compared with 35%) and source (rice straw compared with a mixture of rice straw and corn silage) on feed intake, rumen fermentation, and microbial populations. Feed intake (10.7-12.6 kg/d) and fiber degradation (0.584-0.692) greatly differed (P ≤ 0.05) between cows fed the 4 diets, leading to large differences (P ≤ 0.05) in gaseous methane yield (27.2-37.3 g/kg organic matter digested), dissolved hydrogen (0.258-1.64 μmol/L), rumen fermentation products, and microbiota. Ruminal dissolved hydrogen was negatively correlated (r 0.40; P < 0.05) with molar proportions of propionate and n-butyrate, numbers of methanogens, and abundance of Selenomonas ruminantium and Prevotella spp. Ruminal dissolved hydrogen was positively correlated (r = 0.93; P < 0.001) with Gibbs free energy changes of reactions producing greater acetate and hydrogen, but not correlated with those reactions producing more propionate without hydrogen. Changes in fermentation pathways from acetate toward propionate production and in microbiota from fibrolytic toward amylolytic species were closely associated with ruminal dissolved hydrogen in lactating dairy cows. An unresolved paradox was that greater dissolved hydrogen was associated with greater numbers of methanogens but with lower gaseous methane emissions. © 2016 American Society for Nutrition.

  10. Chronic Diarrhea Associated with High Teriflunomide Blood Concentration.

    Science.gov (United States)

    Duquette, André; Frenette, Anne Julie; Doré, Maxime

    2016-06-01

    To report the case of a patient treated with leflunomide that presented with chronic diarrhea associated with high teriflunomide blood concentration. An 84-year-old woman taking leflunomide 20 mg once daily for the past 2 years to treat rheumatoid arthritis (RA) was investigated for severe chronic diarrhea that had been worsening for the past 5 months. The patient's general condition progressively deteriorated and included electrolyte imbalances and a transient loss of consciousness. Therefore, hospitalization was required. Teriflunomide blood concentration was 156 mg/L. After 11 days of cholestyramine washout therapy, teriflunomide blood concentration was reduced to 6 mg/L. As the teriflunomide levels decreased, diarrhea improved. All other possible causes of diarrhea were ruled out. The patient's diarrhea finally resolved 26 days after treatment with cholestyramine. Diarrhea is a known adverse effect of leflunomide. In this report, the severe diarrhea was associated with high blood teriflunomide concentrations. Available data suggests an association between teriflunomide concentrations greater than 50 mg/L and lower disease activity, but toxic teriflunomide levels still have to be clarified. Further studies are needed to establish the optimal therapeutic levels of teriflunomide. However, therapeutic drug monitoring of teriflunomide blood concentrations may be helpful to improve effectiveness and to prevent toxicity in patients taking leflunomide for RA, particularly in those with suboptimal therapeutic response to leflunomide or in patients with toxicity suspected to be induced by leflunomide.

  11. Stability of human telomere quadruplexes at high DNA concentrations.

    Science.gov (United States)

    Kejnovská, Iva; Vorlíčková, Michaela; Brázdová, Marie; Sagi, Janos

    2014-04-01

    For mimicking macromolecular crowding of DNA quadruplexes, various crowding agents have been used, typically PEG, with quadruplexes of micromolar strand concentrations. Thermal and thermodynamic stabilities of these quadruplexes increased with the concentration of the agents, the rise depended on the crowder used. A different phenomenon was observed, and is presented in this article, when the crowder was the quadruplex itself. With DNA strand concentrations ranging from 3 µM to 9 mM, the thermostability did not change up to ∼2 mM, above which it increased, indicating that the unfolding quadruplex units were not monomolecular above ∼2 mM. The results are explained by self-association of the G-quadruplexes above this concentration. The ΔG(°) 37 values, evaluated only below 2 mM, did not become more negative, as with the non-DNA crowders, instead, slightly increased. Folding topology changed from antiparallel to hybrid above 2 mM, and then to parallel quadruplexes at high, 6-9 mM strand concentrations. In this range, the concentration of the DNA phosphate anions approached the concentration of the K(+) counterions used. Volume exclusion is assumed to promote the topological changes of quadruplexes toward the parallel, and the decreased screening of anions could affect their stability. Copyright © 2013 Wiley Periodicals, Inc.

  12. Non-Intrusive, Real-Time, On-Line Temperature Sensor for Superheated Hydrogen at High Pressure and High Flow Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The SSC needs a hydrogen temperature sensor that can provide high accuracy, fast response and can be operated on a superheated hydrogen (SHH2) environment. This will...

  13. Ultrasonochemical-Assisted Synthesis of CuO Nanorods with High Hydrogen Storage Ability

    Directory of Open Access Journals (Sweden)

    Gang Xiao

    2011-01-01

    Full Text Available Uniform CuO nanorods with different size have been synthesized in a water-alcohol solution through a fast and facile ultrasound irradiation assistant route. Especially, the as-prepared CuO nanorods have shown a strong size-induced enhancement of electrochemical hydrogen storage performance and exhibit a notable hydrogen storage capacity and big BET surface area. These results further implied that the as-prepared CuO nanorods could be a promising candidate for electrochemical hydrogen storage applications. The observation of the comparison experiments with different concentrations of NaOH, ethanol, CTAB, and HTMA while keeping other synthetic parameters unchanged leads to the morphology and size change of CuO products.

  14. High shear treatment of concentrates and drying conditions influence the solubility of milk protein concentrate powders.

    Science.gov (United States)

    Augustin, Mary Ann; Sanguansri, Peerasak; Williams, Roderick; Andrews, Helen

    2012-11-01

    The solubility of milk protein concentrate (MPC) powders was influenced by the method used for preparing the concentrate, drying conditions, and the type of dryer used. Increasing total solids of the ultrafiltered concentrates (23% total solids, TS) by diafiltration to 25% TS or evaporation to 31% TS decreased the solubility of MPC powders (80-83% protein, w/w dry basis), with ultrafiltration followed by evaporation to higher total solids having the greater detrimental effect on solubility. High shear treatment (homogenisation at 350/100 bar, microfluidisation at 800 bar or ultrasonication at 24 kHz, 600 watts) of ultrafiltered and diafiltered milk protein concentrates prior to spray drying increased the nitrogen solubility of MPC powders (82% protein, w/w dry basis). Of the treatments applied, microfluidisation was the most effective for increasing nitrogen solubility of MPC powders after manufacture and during storage. Manufacture of MPC powders (91% protein, w/w dry basis) prepared on two different pilot-scale dryers (single stage or two stage) from milk protein concentrates (20% TS) resulted in powders with different nitrogen solubility and an altered response to the effects of microfluidisation. Microfluidisation (400, 800 and 1200 bar) of the concentrate prior to drying resulted in increased long term solubility of MPC powders that were prepared on a single stage dryer but not those produced on a two stage spray dryer. This work demonstrates that microfluidisation can be used as a physical intervention for improving MPC powder solubility. Interactions between the method of preparation and treatment of concentrate prior to drying, the drying conditions and dryer type all influence MPC solubility characteristics.

  15. High Efficiency Generation of Hydrogen Fuels using Nuclear Power Annual Report August, 2000 - July 2001

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L.C.

    2002-11-01

    OAK B188 High Efficiency Generation of Hydrogen Fuels using Nuclear Power Annual Report August 2000 - July 2001. Currently no large scale, cost-effective, environmentally attractive hydrogen production process is available for commercialization nor has such a process been identified. Hydrogen is a promising energy carrier, which potentially could replace the fossil fuels used in the transportation sector of our economy. Carbon dioxide emissions from fossil fuel combustion are thought to be responsible for global warming. The purpose of this work is to determine the potential for efficient, cost-effective, large-scale production of hydrogen utilizing high temperature heat from an advanced nuclear power station. The benefits of this work will include the generation of a low-polluting transportable energy feedstock in an efficient method that has little or no implication for greenhouse gas emissions from a primary energy source whose availability and sources are domestically controlled. This will help to ensure energy for a future transportation/energy infrastructure that is not influenced/controlled by foreign governments. This report describes work accomplished during the second year (Phase 2) of a three year project whose objective is to ''define an economically feasible concept for production of hydrogen, by nuclear means, using an advanced high temperature nuclear reactor as the energy source.'' The emphasis of the first year (Phase 1) was to evaluate thermochemical processes which offer the potential for efficient, cost-effective, large-scale production of hydrogen from water, in which the primary energy input is high temperature heat from an advanced nuclear reactor and to select one (or, at most, three) for further detailed consideration. Phase 1 met its goals and did select one process, the sulfur-iodine process, for investigation in Phases 2 and 3. The combined goals of Phases 2 and 3 were to select the advanced nuclear reactor best

  16. High-concentration planar microtracking photovoltaic system exceeding 30% efficiency

    Science.gov (United States)

    Price, Jared S.; Grede, Alex J.; Wang, Baomin; Lipski, Michael V.; Fisher, Brent; Lee, Kyu-Tae; He, Junwen; Brulo, Gregory S.; Ma, Xiaokun; Burroughs, Scott; Rahn, Christopher D.; Nuzzo, Ralph G.; Rogers, John A.; Giebink, Noel C.

    2017-08-01

    Prospects for concentrating photovoltaic (CPV) power are growing as the market increasingly values high power conversion efficiency to leverage now-dominant balance of system and soft costs. This trend is particularly acute for rooftop photovoltaic power, where delivering the high efficiency of traditional CPV in the form factor of a standard rooftop photovoltaic panel could be transformative. Here, we demonstrate a fully automated planar microtracking CPV system solar cell at >660× concentration ratio over a 140∘ full field of view. In outdoor testing over the course of two sunny days, the system operates automatically from sunrise to sunset, outperforming a 17%-efficient commercial silicon solar cell by generating >50% more energy per unit area per day in a direct head-to-head competition. These results support the technical feasibility of planar microtracking CPV to deliver a step change in the efficiency of rooftop solar panels at a commercially relevant concentration ratio.

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

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoung Joon; Yoo, Seung Chang [Department of Nuclear Science and Engineering, School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919 (Korea, Republic of); Jin, Hyung-Ha; Kwon, Junhyun; Choi, Min-Jae; Hwang, Seong Sik [Nuclear Materials Safety Research Division, Korea Atomic Energy Research Institute (KAERI), 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Kim, Ji Hyun, E-mail: kimjh@unist.ac.kr [Department of Nuclear Science and Engineering, School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919 (Korea, Republic of)

    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. - Highlights: • 316L Stainless steels were used for the study of crack growth behavior in PWR water. • Warm rolling was applied to simulate the irradiation hardening of stainless steels. • DH concentration was changed to see the effect on crack growth and oxide structure. • Warm-rolled stainless steels showed higher rates of corrosion and crack growth. • Higher DH concentration also promoted the rates of corrosion and crack growth.

  18. Polyaspartic Acid Concentration Controls the Rate of Calcium Phosphate Nanorod Formation in High Concentration Systems

    Energy Technology Data Exchange (ETDEWEB)

    Krogstad, Daniel V. [Biosystems and; Wang, Dongbo [Biosystems and; Lin-Gibson, Sheng [Biosystems and

    2017-08-31

    Polyelectrolytes are known to greatly affect calcium phosphate (CaP) mineralization. The reaction kinetics as well as the CaP phase, morphology and aggregation state depend on the relative concentrations of the polyelectrolyte and the inorganic ions in a complex, nonlinear manner. This study examines the structural evolution and kinetics of polyaspartic acid (pAsp) directed CaP mineralization at high concentrations of polyelectrolytes, calcium, and total phosphate (19–30 mg/mL pAsp, 50–100 mM Ca2+, Ca/P = 2). Using a novel combination of characterization techniques including cryogenic transmission electron microscopy (cryo-TEM), spectrophotometry, X-ray total scattering pair distribution function analysis, and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), it was determined that the CaP mineralization occurred over four transition steps. The steps include the formation of aggregates of pAsp stabilized CaP spherical nanoparticles (sNP), crystallization of sNP, oriented attachment of the sNP into nanorods, and further crystallization of the nanorods. The intermediate aggregate sizes and the reaction kinetics were found to be highly polymer concentration dependent while the sizes of the particles were not concentration dependent. This study demonstrates the complex role of pAsp in controlling the mechanism as well as the kinetics of CaP mineralization.

  19. The H60Si6C54 heterofullerene as high-capacity hydrogen storage medium

    Science.gov (United States)

    Yong, Yongliang; Zhou, Qingxiao; Li, Xiaohong; Lv, Shijie

    2016-07-01

    With the great success in Si atoms doped C60 fullerene and the well-established methods for synthesis of hydrogenated carbon fullerenes, this leads naturally to wonder whether Si-doped fullerenes are possible for special applications such as hydrogen storage. Here by using first-principles calculations, we design a novel high-capacity hydrogen storage material, H60Si6C54 heterofullerene, and confirm its geometric stability. It is found that the H60Si6C54 heterofullerene has a large HOMO-LUMO gap and a high symmetry, indicating it is high chemically stable. Further, our finite temperature simulations indicate that the H60Si6C54 heterofullerene is thermally stable at 300 K. H2 molecules would enter into the cage from the Si-hexagon ring because of lower energy barrier. Through our calculation, a maximum of 21 H2 molecules can be stored inside the H60Si6C54 cage in molecular form, leading to a gravimetric density of 11.11 wt% for 21H2@H60Si6C54 system, which suggests that the hydrogenated Si6C54 heterofullerene could be suitable as a high-capacity hydrogen storage material.

  20. Production of glucose syrups in highly concentrated systems

    NARCIS (Netherlands)

    Veen, van der M.E.; Goot, van der A.J.; Boom, R.M.

    2005-01-01

    We have investigated the hydrolysis of maltodextrins in a high concentration (up to 70%), by means of enzymatic and acid catalysis. The study revealed that the equilibrium compositions of the catalyzed reactions were kinetically determined by the selectivity of the catalyst, the substrate

  1. The virucidal spectrum of a high concentration alcohol mixture

    NARCIS (Netherlands)

    van Engelenburg, F. A. C.; Terpstra, F. G.; Schuitemaker, H.; Moorer, W. R.

    2002-01-01

    The virucidal spectrum of a high concentration alcohol mixture (80% ethanol and 5% isopropanol) was determined for a broad series of lipid-enveloped (LE) and non-lipid-enveloped (NLE) viruses covering all relevant blood-borne viruses. LE viruses were represented by human immunodeficiency virus

  2. High Iridium concentration of alkaline rocks of Deccan and ...

    Indian Academy of Sciences (India)

    R. Narasimhan, Krishtel eMaging Solutions

    and implications to K/T boundary. P N Shukla, N Bhandari∗, Anirban Das, A D Shukla and J S Ray. Physical Research Laboratory, Ahmedabad 380 009, India. ∗e-mail: bhandari@prl.ernet.in. We report here an unusually high concentration of iridium in some alkali basalts and alkaline rocks of Deccan region having an age ...

  3. Beryllium-10 concentrations in water samples of high northern latitudes

    Energy Technology Data Exchange (ETDEWEB)

    Strobl, C.; Eisenhauer, A.; Schulz, V.; Baumann, S.; Mangini, A. [Heidelberger Akademie der Wissenschaften, Heildelberg (Germany); Kubik, P.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    {sup 10}Be concentrations in the water column of high northern latitudes were not available so far. We present different {sup 10}Be profiles from the Norwegian-Greenland Sea, the Arctic Ocean, and the Laptev Sea. (author) 3 fig., 3 refs.

  4. Effects of high concentration of chromium stress on physiological ...

    African Journals Online (AJOL)

    We studied the effects of high concentration of chromium (Cr) stress on physiological and biochemical characters and accumulation of Cr in Pingyang Tezao tea [Camellia sinensis (L) O. Kutze 'Pingyangtezao'] through a pot experiment. The results show that the indicators of photosynthesis were all suppressed with ...

  5. High hydrogen production from glycerol or glucose by electrohydrogenesis using microbial electrolysis cells

    KAUST Repository

    Selembo, Priscilla A.

    2009-07-01

    The use of glycerol for hydrogen gas production was examined via electrohydrogenesis using microbial electrolysis cells (MECs). A hydrogen yield of 3.9 mol-H2/mol was obtained using glycerol, which is higher than that possible by fermentation, at relatively high rates of 2.0 ± 0.4 m3/m3 d (Eap = 0.9 V). Under the same conditions, hydrogen was produced from glucose at a yield of 7.2 mol-H2/mol and a rate of 1.9 ± 0.3 m3/m3 d. Glycerol was completely removed within 6 h, with 56% of the electrons in intermediates (primarily 1,3-propanediol), with the balance converted to current, intracellular storage products or biomass. Glucose was removed within 5 h, but intermediates (mainly propionate) accounted for only 19% of the electrons. Hydrogen was also produced using the glycerol byproduct of biodiesel fuel production at a rate of 0.41 ± 0.1 m3/m3 d. These results demonstrate that electrohydrogenesis is an effective method for producing hydrogen from either pure glycerol or glycerol byproducts of biodiesel fuel production. © 2009 International Association for Hydrogen Energy.

  6. Hydrogen Fuel System Design Trades for High-Altitude Long-Endurance Remotely- Operated Aircraft

    Science.gov (United States)

    Millis, Marc G.; Tornabene, Robert T.; Jurns, John M.; Guynn, Mark D.; Tomsik, Thomas M.; VanOverbeke, Thomas J.

    2009-01-01

    Preliminary design trades are presented for liquid hydrogen fuel systems for remotely-operated, high-altitude aircraft that accommodate three different propulsion options: internal combustion engines, and electric motors powered by either polymer electrolyte membrane fuel cells or solid oxide fuel cells. Mission goal is sustained cruise at 60,000 ft altitude, with duration-aloft a key parameter. The subject aircraft specifies an engine power of 143 to 148 hp, gross liftoff weight of 9270 to 9450 lb, payload of 440 lb, and a hydrogen fuel capacity of 2650 to 2755 lb stored in two spherical tanks (8.5 ft inside diameter), each with a dry mass goal of 316 lb. Hydrogen schematics for all three propulsion options are provided. Each employs vacuum-jacketed tanks with multilayer insulation, augmented with a helium pressurant system, and using electric motor driven hydrogen pumps. The most significant schematic differences involve the heat exchangers and hydrogen reclamation equipment. Heat balances indicate that mission durations of 10 to 16 days appear achievable. The dry mass for the hydrogen system is estimated to be 1900 lb, including 645 lb for each tank. This tank mass is roughly twice that of the advanced tanks assumed in the initial conceptual vehicle. Control strategies are not addressed, nor are procedures for filling and draining the tanks.

  7. Hydrogen storage materials discovery via high throughput ball milling and gas sorption.

    Science.gov (United States)

    Li, Bin; Kaye, Steven S; Riley, Conor; Greenberg, Doron; Galang, Daniel; Bailey, Mark S

    2012-06-11

    The lack of a high capacity hydrogen storage material is a major barrier to the implementation of the hydrogen economy. To accelerate discovery of such materials, we have developed a high-throughput workflow for screening of hydrogen storage materials in which candidate materials are synthesized and characterized via highly parallel ball mills and volumetric gas sorption instruments, respectively. The workflow was used to identify mixed imides with significantly enhanced absorption rates relative to Li2Mg(NH)2. The most promising material, 2LiNH2:MgH2 + 5 atom % LiBH4 + 0.5 atom % La, exhibits the best balance of absorption rate, capacity, and cycle-life, absorbing >4 wt % H2 in 1 h at 120 °C after 11 absorption-desorption cycles.

  8. High-performance a -Si/c-Si heterojunction photoelectrodes for photoelectrochemical oxygen and hydrogen evolution

    KAUST Repository

    Wang, Hsin Ping

    2015-05-13

    Amorphous Si (a-Si)/crystalline Si (c-Si) heterojunction (SiHJ) can serve as highly efficient and robust photoelectrodes for solar fuel generation. Low carrier recombination in the photoelectrodes leads to high photocurrents and photovoltages. The SiHJ was designed and fabricated into both photoanode and photocathode with high oxygen and hydrogen evolution efficiency, respectively, by simply coating of a thin layer of catalytic materials. The SiHJ photoanode with sol-gel NiOx as the catalyst shows a current density of 21.48 mA/cm2 at the equilibrium water oxidation potential. The SiHJ photocathode with 2 nm sputter-coated Pt catalyst displays excellent hydrogen evolution performance with an onset potential of 0.640 V and a solar to hydrogen conversion efficiency of 13.26%, which is the highest ever reported for Si-based photocathodes. © 2015 American Chemical Society.

  9. Core--strategy leading to high reversible hydrogen storage capacity for NaBH4.

    Science.gov (United States)

    Christian, Meganne L; Aguey-Zinsou, Kondo-François

    2012-09-25

    Owing to its high storage capacity (10.8 mass %), sodium borohydride (NaBH(4)) is a promising hydrogen storage material. However, the temperature for hydrogen release is high (>500 °C), and reversibility of the release is unachievable under reasonable conditions. Herein, we demonstrate the potential of a novel strategy leading to high and stable hydrogen absorption/desorption cycling for NaBH(4) under mild pressure conditions (4 MPa). By an antisolvent precipitation method, the size of NaBH(4) particles was restricted to a few nanometers (hydrogen at 400 °C. Further encapsulation of these nanoparticles upon reaction of nickel chloride at their surface allowed the synthesis of a core--shell nanostructure, NaBH(4)@Ni, and this provided a route for (a) the effective nanoconfinement of the melted NaBH(4) core and its dehydrogenation products, and (b) reversibility and fast kinetics owing to short diffusion lengths, the unstable nature of nickel borohydride, and possible modification of reaction paths. Hence at 350 °C, a reversible and steady hydrogen capacity of 5 mass % was achieved for NaBH(4)@Ni; 80% of the hydrogen could be desorbed or absorbed in less than 60 min, and full capacity was reached within 5 h. To the best of our knowledge, this is the first time that such performances have been achieved with NaBH(4). This demonstrates the potential of the strategy in leading to major advancements in the design of effective hydrogen storage materials from pristine borohydrides.

  10. Hydrogen oxidation at high pressure and intermediate temperatures: experiments and kinetic modeling

    DEFF Research Database (Denmark)

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

    2015-01-01

    Hydrogen oxidation at 50 bar and temperatures of 700–900 K was investigated in a high pressure laminar flow reactor under highly diluted conditions. The experiments provided information about H 2 oxidation at pressures above the third explosion limit. The fuel–air equivalence ratio of the reactants...

  11. High concentration of antimitochondrial antibodies predicts progressive primary biliary cirrhosis.

    Science.gov (United States)

    Flisiak, Robert; Pelszynska, Maria; Prokopowicz, Danuta; Rogalska, Magdalena; Grygoruk, Urszula

    2005-09-28

    To evaluate the serum concentration of antimitochondrial antibodies (AMAs) as a prognostic indicator of progressive primary biliary cirrhosis (pPBC). Serum concentrations of AMA subtypes (anti-M2, anti-M4, and anti-M9), biochemical indices of liver function and Mayo risk factor (MRF) were determined in 30 women with diagnosed primary biliary cirrhosis (PBC) selected among 348 females with elevated alkaline phosphatase but without signs of hepatic decompensation. They were followed up for 5 years for possible development of hepatic decompensation. Anti-M2 concentration was significantly correlated with bilirubin and albumin levels as well as MRF, whereas anti-M4 was significantly correlated with albumin level, prothrombin time and MRF. During the 5-year follow-up, progressive PBC (pPBC) was diagnosed in 3 among 23 patients available for evaluation. These 3 patients were positive for both anti-M2 and anti-M4. Anti-M2 serum concentration exceeded 1 300 RU/mL in patients with pPBC and only in 1 among 20 non-progressive PBC persons (5%). Anti-M4 serum concentration exceeded 400 RU/mL in 2 of the progressive patients and none in the non-progressive group. In contrast, anti-M9 serum concentration was below 100 RU/mL in all patients with pPBC, and higher than 100 RU/mL in 11 women (55%) among the non-progressive group. Females with elevated alkaline phosphatase and high anti-M2 and anti-M4 concentrations are at a high risk for developing pPBC. Quantitative AMA detection should be considered as a method for early diagnosis of pPBC.

  12. Auxin increases the hydrogen peroxide (H2O2) concentration in tomato (Solanum lycopersicum) root tips while inhibiting root growth.

    Science.gov (United States)

    Ivanchenko, Maria G; den Os, Désirée; Monshausen, Gabriele B; Dubrovsky, Joseph G; Bednárová, Andrea; Krishnan, Natraj

    2013-10-01

    The hormone auxin and reactive oxygen species (ROS) regulate root elongation, but the interactions between the two pathways are not well understood. The aim of this study was to investigate how auxin interacts with ROS in regulating root elongation in tomato, Solanum lycopersicum. Wild-type and auxin-resistant mutant, diageotropica (dgt), of tomato (S. lycopersicum 'Ailsa Craig') were characterized in terms of root apical meristem and elongation zone histology, expression of the cell-cycle marker gene Sl-CycB1;1, accumulation of ROS, response to auxin and hydrogen peroxide (H2O2), and expression of ROS-related mRNAs. The dgt mutant exhibited histological defects in the root apical meristem and elongation zone and displayed a constitutively increased level of hydrogen peroxide (H2O2) in the root tip, part of which was detected in the apoplast. Treatments of wild-type with auxin increased the H2O2 concentration in the root tip in a dose-dependent manner. Auxin and H2O2 elicited similar inhibition of cell elongation while bringing forth differential responses in terms of meristem length and number of cells in the elongation zone. Auxin treatments affected the expression of mRNAs of ROS-scavenging enzymes and less significantly mRNAs related to antioxidant level. The dgt mutation resulted in resistance to both auxin and H2O2 and affected profoundly the expression of mRNAs related to antioxidant level. The results indicate that auxin regulates the level of H2O2 in the root tip, so increasing the auxin level triggers accumulation of H2O2 leading to inhibition of root cell elongation and root growth. The dgt mutation affects this pathway by reducing the auxin responsiveness of tissues and by disrupting the H2O2 homeostasis in the root tip.

  13. Pressure Relief Devices for High-Pressure Gaseous Storage Systems: Applicability to Hydrogen Technology

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-11-01

    Pressure relief devices (PRDs) are viewed as essential safety measures for high-pressure gas storage and distribution systems. These devices are used to prevent the over-pressurization of gas storage vessels and distribution equipment, except in the application of certain toxic gases. PRDs play a critical role in the implementation of most high-pressure gas storage systems and anyone working with these devices should understand their function so they can be designed, installed, and maintained properly to prevent any potentially dangerous or fatal incidents. As such, the intention of this report is to introduce the reader to the function of the common types of PRDs currently used in industry. Since high-pressure hydrogen gas storage systems are being developed to support the growing hydrogen energy infrastructure, several recent failure incidents, specifically involving hydrogen, will be examined to demonstrate the results and possible mechanisms of a device failure. The applicable codes and standards, developed to minimize the risk of failure for PRDs, will also be reviewed. Finally, because PRDs are a critical component for the development of a successful hydrogen energy infrastructure, important considerations for pressure relief devices applied in a hydrogen gas environment will be explored.

  14. Tooth bleaching by different concentrations of carbamide peroxide and hydrogen peroxide whitening strips: an in vitro study.

    Science.gov (United States)

    Sulieman, Munther; MacDonald, Emma; Rees, Jeremy S; Newcombe, Robert G; Addy, Martin

    2006-01-01

    To investigate the tooth whitening effects of various concentrations of carbamide peroxide (CP) gels and 6% hydrogen peroxide (HP) whitening strips used on an intrinsic, in vitro stain model in a simulated home-applied bleaching protocol. Extracted third molars were sectioned and stained to Vita shade C4 using a standardized tea solution. Stained specimens were then bleached with 10, 15, 20, 22, and 30% CP gels applied in custom-made trays for 8-hour sessions for 14 days. A 6% HP whitening strip product was also tested in a regimen of twice-daily 30-minute treatments for 14 days. Shades were assessed at baseline and at 2, 5, 7, 10, and 14 days of treatment using a shade guide (SG) and a shade vision system (SVS), recorded as shade guide unit (SGU) changes from baseline, and CIE L*a*b* recordings using a chromometer. By day 14, all CP treatments resulted in at least 12 SGU improvements by SG and SVS methods: the HP treatment mean was just less than 12 SGU. With the chromometer, the CP improvements ranged from approximately 19 to 28 units and 16 units for the HP whitening strips. Observationally, by SG and SVS, CP treatments achieved the maximum improvement (12-13 SGU) at different time points: day 5 for 30% CP, day 10 for 22% CP, and day 14 for the other three treatments. SG and SVS data were virtually binary, switching from 0 to scores of 9 or above as bleaching progressed. The differences between the six treatments in the mean day to achieve a positive SG or SVS score (9 or more units) approached significance. For each of the SG, SVS, and L*a*b* scores, the dose-response correlation with CP concentration was significant at one or more assessment times. SG and SVS showed extremely strong agreement in detecting change and substantial agreement with L*a*b*. This in vitro study supports the limited data available from the very few available randomized controlled clinical trials indicating that CP and HP home-use bleaching systems can achieve considerable tooth

  15. Concentric circular focusing reflector realized using high index contrast gratings

    Science.gov (United States)

    Fang, Wenjing; Huang, Yongqing; Fei, Jiarui; Duan, Xiaofeng; Liu, Kai; Ren, Xiaomin

    2017-11-01

    A non-periodic concentric circular high index contrast grating (CC-HCG) focusing reflector on 500 nm silicon-on-insulator (SOI) platform is fabricated and experimentally demonstrated. The proposed mirror is realized with phase modulation of wave front in a high reflectivity region. The circular structure based HCG focusing reflector has a spot of high concentration at the 10.87 mm with normal incidence for radially polarization, along with the center wavelength set at 1550 nm. The FWHM spot size of the focusing beam decreases to 260 μm, and the intensity increases to 1.26 compared with the incident beam. The focusing efficiency of about 80% is observed at 1550 nm in the experimental measurement.

  16. High-Sulfur-Vacancy Amorphous Molybdenum Sulfide as a High Current Electrocatalyst in Hydrogen Evolution

    KAUST Repository

    Lu, Ang-Yu

    2016-08-31

    The remote hydrogen plasma is able to create abundant S-vacancies on amorphous molybdenum sulfide (a-MoSx) as active sites for hydrogen evolution. The results demonstrate that the plasma-treated a-MoSx exhibits superior performance and higher stability than Pt in a proton exchange membrane based electrolyzers measurement as a proof-of-concept of industrial application.

  17. A high-porosity carbon molybdenum sulphide composite with enhanced electrochemical hydrogen evolution and stability

    DEFF Research Database (Denmark)

    Laursen, Anders B.; Vesborg, Peter C. K.; Chorkendorff, Ib

    2013-01-01

    This work describes a highly active and stable acid activated carbon fibre and amorphous MoSx composite hydrogen evolution catalyst. The increased electrochemical-surface area is demonstrated to cause increased catalyst electrodeposition and activity. These composite electrodes also show an impro......This work describes a highly active and stable acid activated carbon fibre and amorphous MoSx composite hydrogen evolution catalyst. The increased electrochemical-surface area is demonstrated to cause increased catalyst electrodeposition and activity. These composite electrodes also show...

  18. Achieving Hydrogen Storage Goals through High-Strength Fiber Glass - Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hong [PPG Industries, Inc., Cheswick, PA (United States); Johnson, Kenneth I. [PPG Industries, Inc., Cheswick, PA (United States); Newhouse, Norman L. [PPG Industries, Inc., Cheswick, PA (United States)

    2017-06-05

    Led by PPG and partnered with Hexagon Lincoln and Pacific Northwest National Laboratory (PNNL), the team recently carried out a project “Achieving Hydrogen Storage Goals through High-Strength Fiber Glass”. The project was funded by DOE’s Fuel Cell Technologies office within the Office of Energy Efficiency and Renewable Energy, starting on September 1, 2014 as a two-year project to assess technical and commercial feasibilities of manufacturing low-cost, high-strength glass fibers to replace T700 carbon fibers with a goal of reducing the composite total cost by 50% of the existing, commercial 700 bar hydrogen storage tanks used in personal vehicles.

  19. Screening of hydrogen storage media applying high pressure thermogravimetry

    DEFF Research Database (Denmark)

    Bentzen, J.J.; Pedersen, Allan Schrøder; Kjøller, J.

    2001-01-01

    A number of commercially available hydride-forming alloys of the MmNi5–xSnx (Mm=mischmetal, a mixture of lanthanides) type were examined using a high pressure, high temperature microbalance,scanning electron microscopy and X-ray diffraction. Activation conditions, reversible storage capacity, wor...

  20. Multiscale structural and electronic control of molybdenum disulfide foam for highly efficient hydrogen production

    Science.gov (United States)

    Deng, Jiao; Li, Haobo; Wang, Suheng; Ding, Ding; Chen, Mingshu; Liu, Chuan; Tian, Zhongqun; Novoselov, K. S.; Ma, Chao; Deng, Dehui; Bao, Xinhe

    2017-04-01

    Hydrogen production through water splitting has been considered as a green, pure and high-efficient technique. As an important half-reaction involved, hydrogen evolution reaction is a complex electrochemical process involving liquid-solid-gas three-phase interface behaviour. Therefore, new concepts and strategies of material design are needed to smooth each pivotal step. Here we report a multiscale structural and electronic control of molybdenum disulfide foam to synergistically promote the hydrogen evolution process. The optimized three-dimensional molybdenum disulfide foam with uniform mesopores, vertically aligned two-dimensional layers and cobalt atoms doping demonstrated a high hydrogen evolution activity and stability. In addition, density functional theory calculations indicate that molybdenum disulfide with moderate cobalt doping content possesses the optimal activity. This study demonstrates the validity of multiscale control in molybdenum disulfide via overall consideration of the mass transport, and the accessibility, quantity and capability of active sites towards electrocatalytic hydrogen evolution, which may also be extended to other energy-related processes.

  1. Electrochemical Hydrogen Storage in a Highly Ordered Mesoporous Carbon

    OpenAIRE

    Dan eLiu; Chao eZeng; Haolin eTan; Dong eZheng; Rong eLi; Deyu eQu; zhizhong eXie; Jiahen eLei; Liang eXiao; Deyang eQu

    2014-01-01

    A highly ordered mesoporous carbon (HOMC) has been synthesized through a strongly acidic, aqueous cooperative assembly route. The structure and morphology of the carbon material were investigated using TEM, SEM, and nitrogen adsorption–desorption isotherms. The carbon was proven to be meso-structural and consisted of graphitic micro-domain with larger interlayer space. Active carbon impedance and electrochemical measurements reveal that the synthesized highly ordered mesoporous carbon (HOMC) ...

  2. Combined Bleaching Technique Using Low and High Hydrogen Peroxide In-Office Bleaching Gel.

    Science.gov (United States)

    Rezende, M; Ferri, L; Kossatz, S; Loguercio, A D; Reis, A

    2016-01-01

    The aim of this study was to evaluate the efficacy, color stability, risk, and intensity of tooth sensitivity (TS) of combined bleaching techniques performed with 20% or 35% hydrogen peroxide for an in-office protocol. Thirty patients were randomly divided into two groups and submitted to a single 45-minute in-office bleaching session with 35% hydrogen peroxide or 20% hydrogen peroxide. At-home bleaching was performed with 10% carbamide peroxide for two hours daily over the course of two weeks. The color was evaluated with the value-oriented shade guide Vita Classical at different periods up to 12 months after bleaching. Patients recorded the intensity of TS using a five-point verbal scale. Color change data were submitted to a two-way repeated-measures analysis of variance and Tukey test (α=0.05). The absolute risk and intensity of TS were compared with the Fisher exact test and Mann-Whitney test, respectively (α=0.05). On average, an effective and similar whitening of three units in shade guide was observed for both groups, which remained stable for 12 months. When both protocols were compared, the one with hydrogen peroxide 35% showed a higher risk (p=0.02) and intensity of TS (p=0.04). In regard to the TS intensity, no significant difference was observed up to 48 hours after in-office bleaching (p=0.09) and during the at-home bleaching phase of the study (p=0.71). The combined bleaching technique using at-home bleaching associated with in-office bleaching was effective and stable over the course of 12 months, regardless of the concentration of the hydrogen peroxide used for in-office bleaching. However, the protocol with 20% hydrogen peroxide produced lower risk and intensity of TS.

  3. Hydrogen Generator

    Science.gov (United States)

    1983-01-01

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

  4. Computational model for a high temperature electrolyzer coupled to a HTTR for efficient nuclear hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Daniel; Rojas, Leorlen; Rosales, Jesus; Castro, Landy; Gamez, Abel; Brayner, Carlos, E-mail: danielgonro@gmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Garcia, Lazaro; Garcia, Carlos; Torre, Raciel de la, E-mail: lgarcia@instec.cu [Instituto Superior de Tecnologias y Ciencias Aplicadas (InSTEC), La Habana (Cuba); Sanchez, Danny [Universidade Estadual de Santa Cruz (UESC), Ilheus, BA (Brazil)

    2015-07-01

    High temperature electrolysis process coupled to a very high temperature reactor (VHTR) is one of the most promising methods for hydrogen production using a nuclear reactor as the primary heat source. However there are not references in the scientific publications of a test facility that allow to evaluate the efficiency of the process and other physical parameters that has to be taken into consideration for its accurate application in the hydrogen economy as a massive production method. For this lack of experimental facilities, mathematical models are one of the most used tools to study this process and theirs flowsheets, in which the electrolyzer is the most important component because of its complexity and importance in the process. A computational fluid dynamic (CFD) model for the evaluation and optimization of the electrolyzer of a high temperature electrolysis hydrogen production process flowsheet was developed using ANSYS FLUENT®. Electrolyzer's operational and design parameters will be optimized in order to obtain the maximum hydrogen production and the higher efficiency in the module. This optimized model of the electrolyzer will be incorporated to a chemical process simulation (CPS) code to study the overall high temperature flowsheet coupled to a high temperature accelerator driven system (ADS) that offers advantages in the transmutation of the spent fuel. (author)

  5. Noble-metal-free tungsten oxide/carbon (WOx/C) hybrid manowires for highly efficient hydrogen evolution

    Science.gov (United States)

    Liu, Changhai; Qiu, Yangyang; Xia, Yujian; Wang, Fang; Liu, Xiaocun; Sun, Xuhui; Liang, Qian; Chen, Zhidong

    2017-11-01

    Developing active, stable, and low-cost electrocatalysts to generate hydrogen is a great challenge in the fields of chemistry and energy. Nonprecious metal catalysts comprised of inexpensive and earth-abundant transition metals are regarded as a promising substitute for noble metal catalysts used in hydrogen evolution reaction (HER), but are still practically unfeasible mainly due to unsatisfactory activity and durability. Here we report a facile two-step preparation method for WOx nanowires with high concentration of oxygen vacancies (OVs) via calcination of W-polydopamine compound precursors. The resulting hybrid material possesses a uniform and ultralong 1D nanowires structure and a rough and raised surface, which can effectively improve the specific surface area. The products exhibit excellent performance for H2 generation: the required overpotentials for 1 and 10 mA cm-2 are 18 and 108 mV, the Tafel slope is 46 mV/decade, and the electrochemically active surface area is estimated to be ˜77.0 m2 g-1. After 1000 cycles, the catalyst works well without significant current density drop. Our experimental results verified metallic transition metal oxides as superior non-Pt electrocatalysts for practical hydrogen evolution reactions.

  6. LANL Virtual Center for Chemical Hydrogen Storage: Chemical Hydrogen Storage Using Ultra-high Surface Area Main Group Materials

    Energy Technology Data Exchange (ETDEWEB)

    Susan M. Kauzlarich; Phillip P. Power; Doinita Neiner; Alex Pickering; Eric Rivard; Bobby Ellis, T. M.; Atkins, A. Merrill; R. Wolf; Julia Wang

    2010-09-05

    The focus of the project was to design and synthesize light element compounds and nanomaterials that will reversibly store molecular hydrogen for hydrogen storage materials. The primary targets investigated during the last year were amine and hydrogen terminated silicon (Si) nanoparticles, Si alloyed with lighter elements (carbon (C) and boron (B)) and boron nanoparticles. The large surface area of nanoparticles should facilitate a favorable weight to volume ratio, while the low molecular weight elements such as B, nitrogen (N), and Si exist in a variety of inexpensive and readily available precursors. Furthermore, small NPs of Si are nontoxic and non-corrosive. Insights gained from these studies will be applied toward the design and synthesis of hydrogen storage materials that meet the DOE 2010 hydrogen storage targets: cost, hydrogen capacity and reversibility. Two primary routes were explored for the production of nanoparticles smaller than 10 nm in diameter. The first was the reduction of the elemental halides to achieve nanomaterials with chloride surface termination that could subsequently be replaced with amine or hydrogen. The second was the reaction of alkali metal Si or Si alloys with ammonium halides to produce hydrogen capped nanomaterials. These materials were characterized via X-ray powder diffraction, TEM, FTIR, TG/DSC, and NMR spectroscopy.

  7. An numerical analysis of high-temperature helium reactor power plant for co-production of hydrogen and electricity

    Science.gov (United States)

    Dudek, M.; Podsadna, J.; Jaszczur, M.

    2016-09-01

    In the present work, the feasibility of using a high temperature gas cooled nuclear reactor (HTR) for electricity generation and hydrogen production are analysed. The HTR is combined with a steam and a gas turbine, as well as with the system for heat delivery for medium temperature hydrogen production. Industrial-scale hydrogen production using copper-chlorine (Cu-Cl) thermochemical cycle is considered and compared with high temperature electrolysis. Presented cycle shows a very promising route for continuous, efficient, large-scale and environmentally benign hydrogen production without CO2 emissions. The results show that the integration of a high temperature helium reactor, with a combined cycle for electric power generation and hydrogen production, may reach very high efficiency and could possibly lead to a significant decrease of hydrogen production costs.

  8. Method for charging a hydrogen getter

    Energy Technology Data Exchange (ETDEWEB)

    Tracy, C. Edwin (Golden, CO); Keyser, Matthew A. (Westminster, CO); Benson, David K. (Golden, CO)

    1998-01-01

    A method for charging a sample of either a permanent or reversible getter material with a high concentration of hydrogen while maintaining a base pressure below 10.sup.-4 torr at room temperature involves placing the sample of hydrogen getter material in a chamber, activating the sample of hydrogen getter material, overcharging the sample of getter material through conventional charging techniques to a high concentration of hydrogen, and then subjecting the sample of getter material to a low temperature vacuum bake-out process. Application of the method results in a reversible hydrogen getter which is highly charged to maximum capacities of hydrogen and which concurrently exhibits minimum hydrogen vapor pressures at room temperatures.

  9. Method for charging a hydrogen getter

    Science.gov (United States)

    Tracy, C.E.; Keyser, M.A.; Benson, D.K.

    1998-09-15

    A method for charging a sample of either a permanent or reversible getter material with a high concentration of hydrogen while maintaining a base pressure below 10{sup {minus}4} torr at room temperature involves placing the sample of hydrogen getter material in a chamber, activating the sample of hydrogen getter material, overcharging the sample of getter material through conventional charging techniques to a high concentration of hydrogen, and then subjecting the sample of getter material to a low temperature vacuum bake-out process. Application of the method results in a reversible hydrogen getter which is highly charged to maximum capacities of hydrogen and which concurrently exhibits minimum hydrogen vapor pressures at room temperatures. 9 figs.

  10. Evaluation of the high temperature electrolysis of steam to produce hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Youngjoon; Park, Wonseok; Chang, Jonghwa; Park, Jongkuen [Korea Atomic Energy Research Institute, 150 Dukjin-dong, Yuseong-gu, Daejeon (Korea)

    2007-07-15

    A very high temperature gas-cooled reactor (VHTR) can be effectively used for hydrogen production through several CO{sub 2}-free alternative technologies, such as the Sulfur-Iodine (SI) cycle, the high temperature electrolysis of steam (HTES), and others. In our current study, the electrochemical thermodynamic properties and the overall thermal efficiency of the VHTR-assisted hydrogen production system by using the HTES technology have been calculated as a function of the operating temperature in the range of 600-1000 {sup circle} C. On the other hand, the effect of not only the gas turbine efficiency but also the recovery of waste heat for the overall hydrogen production thermal efficiency has also been evaluated. The thermal efficiency defined by a high heat value of the produced hydrogen (HHV) divided by the total energy of the heat and the electricity required to produce the hydrogen was adopted in our evaluation scheme. As a result, a maximized overall thermal efficiency of about 48% can be anticipated at 1000 {sup circle} C. Compared with a thermal efficiency of 27% by a conventional alkaline solution electrolysis at lower temperatures, a hydrogen production by the VHTR-assisted HTES can save on the required energy by about 2 times. The sensitivity of the operating temperature for the overall thermal efficiency defined by {delta}{eta}{sub {delta}} {sub T}/{eta}{sub T} is about 14.3% in the range of 600 to 1000 {sup circle} C. From the aspect of a conservative gas turbine efficiency and a reasonable recovery of the waste heat, an overall feasible efficiency of 46% is anticipated at 850 {sup circle} C. (author)

  11. High concentration biotherapeutic formulation and ultrafiltration: Part 1 pressure limits.

    Science.gov (United States)

    Lutz, Herb; Arias, Joshua; Zou, Yu

    2017-01-01

    High therapeutic dosage requirements and the desire for ease of administration drive the trend to subcutaneous administration using delivery systems such as subcutaneous pumps and prefilled syringes. Because of dosage volume limits, prefilled syringe administration requires higher concentration liquid formulations, limited to about 30 cP or roughly 100-300 g L-1 for mAb's. Ultrafiltration (UF) processes are routinely used to formulate biological therapeutics. This article considers pressure constraints on the UF process that may limit its ability to achieve high final product concentrations. A system hardware analysis shows that the ultrafiltration cassette pressure drop is the major factor limiting UF systems. Additional system design recommendations are also provided. The design and performance of a new cassette with a lower feed channel flow resistance is described along with 3D modeling of feed channel pressure drop. The implications of variations in cassette flow channel resistance for scaling up and setting specifications are considered. A recommendation for a maximum pressure specification is provided. A review of viscosity data and theory shows that molecular engineering, temperature, and the use of viscosity modifying excipients including pH adjustment can be used to achieve higher concentrations. The combined use of a low pressure drop cassette with excipients further increased final concentrations by 35%. Guidance is provided on system operation to control hydraulics during final concentration. These recommendations should allow one to design and operate systems to routinely achieve the 30 cP target final viscosity capable of delivery using a pre-filled syringe. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:113-124, 2017. © 2016 American Institute of Chemical Engineers.

  12. Ion aggregation in high salt solutions. V. Graph entropy analyses of ion aggregate structure and water hydrogen bonding network

    Science.gov (United States)

    Choi, Jun-Ho; Cho, Minhaeng

    2016-05-01

    Dissolved ions in water tend to form polydisperse ion aggregates such as ion pairs, relatively compact ion clusters, and even spatially extended ion networks with increasing salt concentration. Combining molecular dynamics simulation and graph theoretical analysis methods, we recently studied morphological structures of ion aggregates with distinctively different characteristics. They can be distinguished from each other by calculating various spectral graph theoretical properties such as eigenvalues and eigenvectors of adjacency matrices of ion aggregates and water hydrogen-bonding networks, minimum path lengths, clustering coefficients, and degree distributions. Here, we focus on percolation and graph entropic properties of ion aggregates and water hydrogen-bonding networks in high salt solutions. Ion network-forming K+ and SCN- ions at high concentrations show a percolating behavior in their aqueous solutions, but ion cluster-forming ions in NaCl solutions do not show such a transition from isolated ion aggregates to percolating ion-water mixture morphology. Despite that the ion aggregate structures are strikingly different for either cluster- or network-forming ions in high salt solutions, it is interesting that the water structures remain insensitive to the electrostatic properties, such as charge densities and polydentate properties, of dissolved ions, and morphological structures of water H-bonding networks appear to be highly robust regardless of the nature and concentration of salt. We anticipate that the present graph entropy analysis results would be of use in understanding a variety of anomalous behaviors of interfacial water around biomolecules as well as electric conductivities of high electrolyte solutions.

  13. Ion aggregation in high salt solutions. V. Graph entropy analyses of ion aggregate structure and water hydrogen bonding network.

    Science.gov (United States)

    Choi, Jun-Ho; Cho, Minhaeng

    2016-05-28

    Dissolved ions in water tend to form polydisperse ion aggregates such as ion pairs, relatively compact ion clusters, and even spatially extended ion networks with increasing salt concentration. Combining molecular dynamics simulation and graph theoretical analysis methods, we recently studied morphological structures of ion aggregates with distinctively different characteristics. They can be distinguished from each other by calculating various spectral graph theoretical properties such as eigenvalues and eigenvectors of adjacency matrices of ion aggregates and water hydrogen-bonding networks, minimum path lengths, clustering coefficients, and degree distributions. Here, we focus on percolation and graph entropic properties of ion aggregates and water hydrogen-bonding networks in high salt solutions. Ion network-forming K(+) and SCN(-) ions at high concentrations show a percolating behavior in their aqueous solutions, but ion cluster-forming ions in NaCl solutions do not show such a transition from isolated ion aggregates to percolating ion-water mixture morphology. Despite that the ion aggregate structures are strikingly different for either cluster- or network-forming ions in high salt solutions, it is interesting that the water structures remain insensitive to the electrostatic properties, such as charge densities and polydentate properties, of dissolved ions, and morphological structures of water H-bonding networks appear to be highly robust regardless of the nature and concentration of salt. We anticipate that the present graph entropy analysis results would be of use in understanding a variety of anomalous behaviors of interfacial water around biomolecules as well as electric conductivities of high electrolyte solutions.

  14. Surface passivation of c-Si for silicon heterojunction solar cells using high-pressure hydrogen diluted plasmas

    Directory of Open Access Journals (Sweden)

    Dimitrios Deligiannis

    2015-09-01

    Full Text Available In this work we demonstrate excellent c-Si surface passivation by depositing a-Si:H in the high-pressure and high hydrogen dilution regime. By using high hydrogen dilution of the precursor gases during deposition the hydrogen content of the layers is sufficiently increased, while the void fraction is reduced, resulting in dense material. Results show a strong dependence of the lifetime on the substrate temperature and a weaker dependence on the hydrogen dilution. After applying a post-deposition annealing step on the samples equilibration of the lifetime occurs independent of the initial nanostructure.

  15. New nitrogen-containing materials for hydrogen storage and their characterization by high-pressure microbalance

    DEFF Research Database (Denmark)

    Vestbø, Andreas Peter

    or liquid form, technologies that are well developed and usable, but not energy efficient. Certain metals and alloys are able to contain hydrogen within practical pressure and temperature ranges very efficient volume-wise, but they are too heavy for use in cars. Recently, attention has turned to the so......-called complex hydrides, which contain hydrogen bound covalently often in very light materials involving elements such as lithium, sodium, nitrogen and aluminum. While these materials typically have high decomposition temperatures, the combination with other compounds helps to destabilize the material resulting...

  16. Control of Hydrogen Environment Embrittlement of Ultra-High Strength Steel for Naval Application

    Science.gov (United States)

    2005-07-01

    to the log da/dt vs. l/T data. Speidel reported simple Arrhenius behavior for lower strength Nimonic 105 (Cyys = 825 MPa) for 0°C < T < 100°C (Speidel...HYDROGEN ASSISTED CRACKING OF HIGH STRENGTH ALLOYS Richard P. Gangloff August. 2003 Page 115 of 194 L (a) R250 nm 250 nm SL (b) R Figure 43: Matching...34Hydrogen in Metals", Eds., I.M. Bernstein and A.W. Thompson, ASM International, Materials Park, OH, 1974, pp. 115 -147. W.W. Gerberich, Y.T. Chen and C

  17. Unexpectedly high pressure for molecular dissociation in liquid hydrogen by electronic simulation.

    Science.gov (United States)

    Mazzola, Guglielmo; Yunoki, Seiji; Sorella, Sandro

    2014-03-19

    The study of the high pressure phase diagram of hydrogen has continued with renewed effort for about one century as it remains a fundamental challenge for experimental and theoretical techniques. Here we employ an efficient molecular dynamics based on the quantum Monte Carlo method, which can describe accurately the electronic correlation and treat a large number of hydrogen atoms, allowing a realistic and reliable prediction of thermodynamic properties. We find that the molecular liquid phase is unexpectedly stable, and the transition towards a fully atomic liquid phase occurs at much higher pressure than previously believed. The old standing problem of low-temperature atomization is, therefore, still far from experimental reach.

  18. Hydrogen bonds and van der waals forces in ice at ambient and high pressures.

    Science.gov (United States)

    Santra, Biswajit; Klimeš, Jiří; Alfè, Dario; Tkatchenko, Alexandre; Slater, Ben; Michaelides, Angelos; Car, Roberto; Scheffler, Matthias

    2011-10-28

    The first principles methods, density-functional theory and quantum Monte Carlo, have been used to examine the balance between van der Waals (vdW) forces and hydrogen bonding in ambient and high-pressure phases of ice. At higher pressure, the contribution to the lattice energy from vdW increases and that from hydrogen bonding decreases, leading vdW to have a substantial effect on the transition pressures between the crystalline ice phases. An important consequence, likely to be of relevance to molecular crystals in general, is that transition pressures obtained from density-functional theory exchange-correlation functionals which neglect vdW forces are greatly overestimated.

  19. Robust, Reliable Low Emission Gas Turbine Combustion of High Hydrogen Content Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Wooldridge, Margaret Stacy [Univ. of Michigan, Ann Arbor, MI (United States); Im, Hong Geum [Univ. of Michigan, Ann Arbor, MI (United States)

    2016-12-16

    The effects of high hydrogen content fuels were studied using experimental, computational and theoretical approaches to understand the effects of mixture and state conditions on the ignition behavior of the fuels. A rapid compression facility (RCF) was used to measure the ignition delay time of hydrogen and carbon monoxide mixtures. The data were combined with results of previous studies to develop ignition regime criteria. Analytical theory and direct numerical simulation were used to validate and interpret the RCF ignition data. Based on the integrated information the ignition regime criteria were extended to non-dimensional metrics which enable application of the results to practical gas turbine combustion systems.

  20. Antibacterial and Toxic Effect of Hydrogen Peroxide Combined with Different Concentrations of Chlorhexidine in Comparison with Sodium Hypochlorite.

    Science.gov (United States)

    Mirhadi, Hosein; Abbaszadegan, Abbas; Ranjbar, Mohammad Ali; Azar, Mohammad Reza; Geramizadeh, Bita; Torabi, Shima; Sadat Aleyasin, Zeinab; Gholami, Ahmad

    2015-12-01

    Hydrogen peroxide (H2O2) has been suggested to be used in sequence or in combination with chlorhexidine (CHX) to enhance the antibacterial activity against Enterococcus faecalis, but there is no research in the literature on the safety and effectiveness of this irrigation protocol. This study aimed to assess the cytocompatibility and antibacterial activity of different concentrations of CHX combined with H2O2in comparison with the activity of 5.25 and 2.5% sodium hypochlorite (NaOCl). Different concentrations of H2O2 (10, 5, 3 and 1%) were exposed to the PDL cells. Then, the solution with minimal cytotoxicity was selected (3% H2O2). The cytocompatibility and antibacterial activity of 0.1, 0.2, 1 and 2% CHX combined with 3% H2O2 were evaluated and compared with 5.25 and 2.5% NaOCl. The differences in the mean viability of PDL cells were evaluated by one-way ANOVA. Kruskal-Wallis and post-hoc Dunn's tests were adopted to compare the antibacterial activity of the solutions against E.faecalis. The viability of PDL cells was lower when treated with 5.25 or 2.5% NaOCl than all combinations of CHX and H2O2.There was no significant difference in the antibacterial activity of the solutions against E.faecalis, except for the 0.1% CHX + 3% H2O2 combination, which had significantly lower efficacy than other groups. All combinations of CHX and H2O2 (used in this study)except 0.1% CHX + 3% H2O2 were efficient irrigants against planktonic E.faecalis and had a better cytocompatibility with PDL cells than 5.25 and 2.5% NaOCl.

  1. Microbial Electrolysis Cells for High Yield Hydrogen Gas Production from Organic Matter

    NARCIS (Netherlands)

    Logan, B.E.; Call, D.; Cheng, S.; Hamelers, H.V.M.; Sleutels, T.H.J.A.; Jeremiasse, A.W.; Rozendal, R.A.

    2008-01-01

    The use of electrochemically active bacteria to break down organic matter, combined with the addition of a small voltage (>0.2 V in practice) in specially designed microbial electrolysis cells (MECs), can result in a high yield of hydrogen gas. While microbial electrolysis was invented only a few

  2. High performance photoelectrochemical hydrogen generation and solar cells with a double type II heterojunction

    NARCIS (Netherlands)

    Lai, Lai-Hung; Gomulya, Widianta; Protesescu, Loredana; Kovalenko, Maksym V.; Loi, Maria A.

    2014-01-01

    We report on the fabrication of CdSe quantum dot (QD) sensitized electrodes by direct adsorption of colloidal QDs on mesoporous TiO2 followed by 3-mercaptopropionic acid (MPA) ligand exchange. High efficiency photoelectrochemical hydrogen generation is demonstrated by means of these electrodes. The

  3. Reorganization of graphite surfaces into carbon micro- and nanoparticles under high flux hydrogen plasma bombardment

    NARCIS (Netherlands)

    Bystrov, K.; van der Vegt, L.; De Temmerman, G.; Arnas, C.; Marot, L.

    2013-01-01

    Fine-grain graphite samples were exposed to high density low temperature (n(e) similar to 10(20)m(-3), T-e similar to 1 eV) hydrogen plasmas in the Pilot-PSI linear plasma generator. Redeposition of eroded carbon is so strong that no external precursor gas injection is necessary for deposits to form

  4. Addition of titanium as a potential catalyst for a high-capacity hydrogen storage medium

    NARCIS (Netherlands)

    Zuliani, F.; Baerends, E.J.

    2008-01-01

    In recent years there has been increased interest in the characterization of titanium as a catalyst for high-capacity hydrogen storage materials. A first-principles study (Yildirim and Ciraci 2005 Phys. Rev. Lett. 94 175501) demonstrated that a single Ti atom coated on a single-walled nanotube

  5. Highly enantioselective synthesis of chiral cyclic allylic amines via Rh-catalyzed asymmetric hydrogenation.

    Science.gov (United States)

    Zhou, Ming; Liu, Tang-Lin; Cao, Min; Xue, Zejian; Lv, Hui; Zhang, Xumu

    2014-07-03

    Highly regioselective and enantioselective asymmetric hydrogenation of cyclic dienamides catalyzed by an Rh-DuanPhos complex has been developed, which provides a readily accessible method for the synthesis of chiral cyclic allylic amines in excellent enantioselectivities (up to 99% ee). The products are valuable chiral building blocks and could be easily transformed to multisubstituted cyclohexane derivatives.

  6. Numerical analysis of accidental hydrogen releases from high pressure storage at low temperatures

    DEFF Research Database (Denmark)

    Markert, Frank; Melideo, Daniele; Baraldi, Daniele

    2014-01-01

    ) and temperatures (down to 20 K), e.g. cryogenic compressed gas storage covers pressures up to 35 MPa and temperatures between 33 K and 338 K. Accurate calculations of high pressure releases require real gas EOS. This paper compares a number of EOS to predict hydrogen properties typical in different storage types...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Effects of high nitrogen concentrations on the growth of submersed macrophytes at moderate phosphorus concentrations.

    Science.gov (United States)

    Yu, Qing; Wang, Hong-Zhu; Li, Yan; Shao, Jian-Chun; Liang, Xiao-Min; Jeppesen, Erik; Wang, Hai-Jun

    2015-10-15

    Eutrophication of lakes leading to loss of submersed macrophytes and higher turbidity is a worldwide phenomenon, attributed to excessive loading of phosphorus (P). However, recently, the role of nitrogen (N) for macrophyte recession has received increasing attention. Due to the close relationship between N and P loading, disentanglement of the specific effects of these two nutrients is often difficult, and some controversy still exists as to the effects of N. We studied the effects of N on submersed macrophytes represented by Vallisneria natans (Lour.) Hara in pots positioned at three depths (0.4 m, 0.8 m, and 1.2 m to form a gradient of underwater light conditions) in 10 large ponds having moderate concentrations of P (TP 0.03 ± 0.04 mg L(-1)) and five targeted concentrations of total nitrogen (TN) (0.5, 2, 10, 20, and 100 mg L(-1)), there were two ponds for each treatment. To study the potential shading effects of other primary producers, we also measured the biomass of phytoplankton (ChlaPhyt) and periphyton (ChlaPeri) expressed as chlorophyll a. We found that leaf length, leaf mass, and root length of macrophytes declined with increasing concentrations of TN and ammonium, while shoot number and root mass did not. All the measured growth indices of macrophytes declined significantly with ChlaPhyt, while none were significantly related to ChlaPeri. Neither ChlaPhyt nor ChlaPeri were, however, significantly negatively related to the various N concentrations. Our results indicate that shading by phytoplankton unrelated to the variation in N loading and perhaps toxic stress exerted by high nitrogen were responsible for the decline in macrophyte growth. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Wet oxidation of real coke wastewater containing high thiocyanate concentration.

    Science.gov (United States)

    Oulego, Paula; Collado, Sergio; Garrido, Laura; Laca, Adriana; Rendueles, Manuel; Díaz, Mario

    2014-01-01

    Coke wastewaters, in particular those with high thiocyanate concentrations, represent an important environmental problem because of their very low biodegradability. In this work, the treatment by wet oxidation of real coke wastewaters containing concentrations of thiocyanate above 17 mM has been studied in a 1-L semi-batch reactor at temperatures between 453 and 493 K, with total oxygen pressures in the range of 2.0-8.0 MPa. A positive effect of the matrix of real coke wastewater was observed, resulting in faster thiocyanate degradation than was obtained with synthetic wastewaters. Besides, the effect of oxygen concentration and temperature on thiocyanate wet oxidation was more noticeable in real effluents than in synthetic wastewaters containing only thiocyanate. It was also observed that the degree of mineralization of the matrix organic compounds was higher when the initial thiocyanate concentration increased. Taking into account the experimental data, kinetic models were obtained, and a mechanism implying free radicals was proposed for thiocyanate oxidation in the matrix considered. In all cases, sulphate, carbonates and ammonium were identified as the main reaction products of thiocyanate wet oxidation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Fabrication procedures for manufacturing high uranium concentration dispersion fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Jose Antonio Batista de; Durazzo, Michelangelo, E-mail: jasouza@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    IPEN developed and made available for routine production the technology for manufacturing dispersion type fuel elements for use in research reactors. However, the fuel produced at IPEN is limited to the uranium concentration of 3.0 g U/c m3 by using the U{sub 3}Si{sub 2}-Al dispersion. Increasing the uranium concentration of the fuel is interesting by the possibility of increasing the reactor core reactivity and lifetime of the fuel. It is possible to increase the concentration of uranium in the fuel up to the technological limit of 4.8 g U/c m3 for the U{sub 3}Si{sub 2}-Al dispersion, which is well placed around the world. This new fuel will be applicable in the new Brazilian- Multipurpose Reactor RMB. This study aimed to develop the manufacturing process of high uranium concentration fuel, redefining the procedures currently used in the manufacture of IPEN. This paper describes the main procedures adjustments that will be necessary. (author)

  11. Microbial Electrolysis Cells for High Yield Hydrogen Gas Production from Organic Matter

    KAUST Repository

    Logan, Bruce E.

    2008-12-01

    The use of electrochemically active bacteria to break down organic matter, combined with the addition of a small voltage (>0.2 V in practice) in specially designed microbial electrolysis cells (MECs), can result in a high yield of hydrogen gas. While microbial electrolysis was invented only a few years ago, rapid developments have led to hydrogen yields approaching 100%, energy yields based on electrical energy input many times greater than that possible by water electrolysis, and increased gas production rates. MECs used to make hydrogen gas are similar in design to microbial fuel cells (MFCs) that produce electricity, but there are important differences in architecture and analytical methods used to evaluate performance. We review here the materials, architectures, performance, and energy efficiencies of these MEC systems that show promise as a method for renewable and sustainable energy production, and wastewater treatment. © 2008 American Chemical Society.

  12. Microbial electrolysis cells for high yield hydrogen gas production from organic matter.

    Science.gov (United States)

    Logan, Bruce E; Call, Douglas; Cheng, Shaoan; Hamelers, Hubertus V M; Sleutels, Tom H J A; Jeremiasse, Adriaan W; Rozendal, René A

    2008-12-01

    The use of electrochemically active bacteria to break down organic matter, combined with the addition of a small voltage (> 0.2 V in practice) in specially designed microbial electrolysis cells (MECs), can result in a high yield of hydrogen gas. While microbial electrolysis was invented only a few years ago, rapid developments have led to hydrogen yields approaching 100%, energy yields based on electrical energy input many times greater than that possible by water electrolysis, and increased gas production rates. MECs used to make hydrogen gas are similar in design to microbial fuel cells (MFCs) that produce electricity, but there are important differences in architecture and analytical methods used to evaluate performance. We review here the materials, architectures, performance, and energy efficiencies of these MEC systems that show promise as a method for renewable and sustainable energy production, and wastewater treatment.

  13. Towards operating direct methanol fuel cells with highly concentrated fuel

    Science.gov (United States)

    Zhao, T. S.; Yang, W. W.; Chen, R.; Wu, Q. X.

    A significant advantage of direct methanol fuel cells (DMFCs) is the high specific energy of the liquid fuel, making it particularly suitable for portable and mobile applications. Nevertheless, conventional DMFCs have to be operated with excessively diluted methanol solutions to limit methanol crossover and the detrimental consequences. Operation with diluted methanol solutions significantly reduces the specific energy of the power pack and thereby prevents it from competing with advanced batteries. In view of this fact, there exists a need to improve conventional DMFC system designs, including membrane electrode assemblies and the subsystems for supplying/removing reactants/products, so that both the cell performance and the specific energy can be simultaneously maximized. This article provides a comprehensive review of past efforts on the optimization of DMFC systems that operate with concentrated methanol. Based on the discussion of the key issues associated with transport of the reactants/products, the strategies to manage the supply/removal of the reactants/products in DMFC operating with highly concentrated methanol are identified. With these strategies, the possible approaches to achieving the goal of concentrated fuel operation are then proposed. Past efforts in the management of the reactants/products for implementing each of the approaches are also summarized and reviewed.

  14. Prediction of colloidal stability of high concentration protein formulations.

    Science.gov (United States)

    Garidel, Patrick; Blume, Alfred; Wagner, Michael

    2015-05-01

    A major aspect determining the colloidal properties of proteins in solution is the interaction between them and with surrounding molecules. These interactions can be described by the concentration dependency of the protein diffusivity (kD), as derived by dynamic light scattering and was determined for different solutions of monoclonal antibodies varying in pH, ionic strength and presence/absence of co-solute(s). Concerning colloidal stability, protein solutions of different kD values are evaluated, based on their initial solution opalescence, to assess protein association. The current investigation shows that solution conditions with large kD values, indicating high repulsive protein-protein interactions, show lower initial opalescence, compared to solution conditions with low kD values. Upon applying stirring stress, to assess colloidal stability, the trend is such that, the higher kD values are, the more stable the protein solutions are, as long as the thermodynamic and conformational stability is not impaired. Besides, kD allows ranking of solution conditions for highly concentrated immunoglobulin solutions up to concentrations of ∼200 mg mL(-1) with regard to protein self-association and thus opalescent properties. The present study shows that the protein interaction parameter kD can be used as a surrogate parameter for a qualitative prediction of protein association and, thus, colloidal protein stability.

  15. SIMULTANEOUS PRODUCTION OF HIGH-PURITY HYDROGEN AND SEQUESTRATION-READY CO2 FROM SYNGAS

    Energy Technology Data Exchange (ETDEWEB)

    Linda Denton; Hana Lorethova; Tomasz Wiltowski; Court Moorefield; Parag Kulkarni; Vladimir Zamansky; Ravi Kumar

    2003-12-01

    This final report summarizes the progress made on the program ''Simultaneous Production of High-Purity Hydrogen and Sequestration-Ready CO{sub 2} from Syngas (contract number DE-FG26-99FT40682)'', during October 2000 through September of 2003. GE Energy and Environmental Research (GE-EER) and Southern Illinois University (SIU) at Carbondale conducted the research work for this program. This program addresses improved methods to efficiently produce simultaneous streams of high-purity hydrogen and separated carbon dioxide from synthesis gas (syngas). The syngas may be produced through either gasification of coal or reforming of natural gas. The process of production of H{sub 2} and separated CO{sub 2} utilizes a dual-bed reactor and regenerator system. The reactor produces hydrogen and the regenerator produces separated CO{sub 2}. The dual-bed system can be operated under either a circulating fluidized-bed configuration or a cyclic fixed-bed configuration. Both configurations were evaluated in this project. The experimental effort was divided into lab-scale work at SIU and bench-scale work at GE-EER. Tests in a lab-scale fluidized bed system demonstrated the process for the conversion of syngas to high purity H{sub 2} and separated CO{sub 2}. The lab-scale system generated up to 95% H{sub 2} (on a dry basis). Extensive thermodynamic analysis of chemical reactions between the syngas and the fluidized solids determined an optimum range of temperature and pressure operation, where the extent of the undesirable reactions is minimum. The cycling of the process between hydrogen generation and oxygen regeneration has been demonstrated. The fluidized solids did not regenerate completely and the hydrogen purity in the reuse cycle dropped to 70% from 95% (on a dry basis). Changes in morphology and particle size may be the most dominant factor affecting the efficiency of the repeated cycling between hydrogen production and oxygen regeneration. The concept of

  16. High pressure in situ diffraction studies of metal-hydrogen systems

    Energy Technology Data Exchange (ETDEWEB)

    Yartys, V.A., E-mail: volodymyr.yartys@ife.no [Institute for Energy Technology, Kjeller NO 2027 (Norway); Norwegian University of Science and Technology, Trondheim NO 7491 (Norway); Denys, R.V. [Institute for Energy Technology, Kjeller NO 2027 (Norway); Karpenko Physico-Mechanical Institute, NAS of Ukraine, Lviv 79601 (Ukraine); Webb, C.J. [Queensland Micro- and Nanotechnology Centre, Griffith University (Australia); Maehlen, J.P. [Institute for Energy Technology, Kjeller NO 2027 (Norway); Gray, E. MacA.; Blach, T. [Queensland Micro- and Nanotechnology Centre, Griffith University (Australia); Isnard, O. [Institute Neel, CNRS/UJF, 38042 Grenoble (France); Barnsley, L.C. [Queensland Micro- and Nanotechnology Centre, Griffith University (Australia)

    2011-09-15

    Research highlights: > CeNi{sub 5}-D{sub 2} and Zr(Fe,Al){sub 2}-D{sub 2} systems were studied by in situ NPD at P up to 1000 bar. > In the hexagonal CeNi{sub 5}D{sub 6.3} deuterium atoms fill three types of interstices. > In the Zr(Fe,Al){sub 2}-based deuterides D atoms occupy the Zr(Fe,Al){sub 2} tetrahedra only D/Zr(Fe,Al){sub 2}, hysteresis and hydrides stability systematically change with Al content. - Abstract: 'Hybrid' hydrogen storage, where hydrogen is stored in both the solid material and as a high pressure gas in the void volume of the tank can improve overall system efficiency by up to 50% compared to either compressed hydrogen or solid materials alone. Thermodynamically, high equilibrium hydrogen pressures in metal-hydrogen systems correspond to low enthalpies of hydrogen absorption-desorption. This decreases the calorimetric effects of the hydride formation-decomposition processes which can assist in achieving high rates of heat exchange during hydrogen loading-removing the bottleneck in achieving low charging times and improving overall hydrogen storage efficiency of large hydrogen stores. Two systems with hydrogenation enthalpies close to -20 kJ/mol H{sub 2} were studied to investigate the hydrogenation mechanism and kinetics: CeNi{sub 5}-D{sub 2} and ZrFe{sub 2-x}Al{sub x} (x = 0.02; 0.04; 0.20)-D{sub 2}. The structure of the intermetallics and their hydrides were studied by in situ neutron powder diffraction at pressures up to 1000 bar and complementary X-ray diffraction. The deuteration of the hexagonal CeNi{sub 5} intermetallic resulted in CeNi{sub 5}D{sub 6.3} with a volume expansion of 30.1%. Deuterium absorption filled three different types of interstices, Ce{sub 2}Ni{sub 2} and Ni{sub 4} tetrahedra, and Ce{sub 2}Ni{sub 3} half-octahedra and was accompanied by a valence change for Ce. Significant hysteresis was observed between deuterium absorption and desorption which profoundly decreased on a second absorption cycle. For the Al

  17. Charge Modulation in Graphitic Carbon Nitride as a Switchable Approach to High-Capacity Hydrogen Storage.

    Science.gov (United States)

    Tan, Xin; Kou, Liangzhi; Tahini, Hassan A; Smith, Sean C

    2015-11-01

    Electrical charging of graphitic carbon nitride nanosheets (g-C4 N3 and g-C3 N4 ) is proposed as a strategy for high-capacity and electrocatalytically switchable hydrogen storage. Using first-principle calculations, we found that the adsorption energy of H2 molecules on graphitic carbon nitride nanosheets is dramatically enhanced by injecting extra electrons into the adsorbent. At full hydrogen coverage, the negatively charged graphitic carbon nitride achieves storage capacities up to 6-7 wt %. In contrast to other hydrogen storage approaches, the storage/release occurs spontaneously once extra electrons are introduced or removed, and these processes can be simply controlled by switching on/off the charging voltage. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Importantly, g-C4 N3 has good electrical conductivity and high electron mobility, which can be a very good candidate for electron injection/release. These predictions may prove to be instrumental in searching for a new class of high-capacity hydrogen storage materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. High concentration methanol fuel cells: Design and theory

    Science.gov (United States)

    Shaffer, Christian E.; Wang, Chao-Yang

    Use of highly concentrated methanol fuel is required for direct methanol fuel cells (DMFCs) to compete with the energy density of Li-ion batteries. Because one mole of H 2O is needed to oxidize one mole of methanol (CH 3OH) in the anode, low water crossover to the cathode or even water back flow from the cathode into the anode is a prerequisite for using highly concentrated methanol. It has previously been demonstrated that low or negative water crossover can be realized by the incorporation of a low-α membrane electrode assembly (MEA), which is essentially an MEA designed for optimal water management, using, e.g. hydrophobic anode and cathode microporous layers (aMPL and cMPL). In this paper we extend the low-α MEA concept to include an anode transport barrier (aTB) between the backing layer and hydrophobic aMPL. The main role of the aTB is to act as a barrier to CH 3OH and H 2O diffusion between a water-rich anode catalyst layer (aCL) and a methanol-rich fuel feed. The primary role of the hydrophobic aMPL in this MEA is to facilitate a low (or negative) water crossover to the cathode. Using a previously developed 1D, two-phase DMFC model, we show that this novel design yields a cell with low methanol crossover (i.e. high fuel efficiency, ∼80%, at a typical operating current density of ∼80-90% of the cell limiting current density), while directly feeding high concentration methanol fuel into the anode. The physics of how the aTB and aMPL work together to accomplish this is fully elucidated. We further show that a thicker, more hydrophilic, more permeable aTB, and thicker, more hydrophobic, and less permeable aMPL are most effective in accomplishing low CH 3OH and H 2O crossover.

  19. The problems of using a high-temperature sodium coolant in nuclear power plants for the production of hydrogen and other innovative applications

    Science.gov (United States)

    Sorokin, A. P.; Alexeev, V. V.; Kuzina, Ju. A.; Konovalov, M. A.

    2017-11-01

    The intensity of the hydrogen sources arriving from the third contour of installation in second in comparison with the hydrogen sources on NPP BN-600 increases by two – three order at using of high-temperature nuclear power plants with the sodium coolant (HT-NPP) for drawing of hydrogen and other innovative applications (gasification and a liquefaction of coal, profound oil refining, transformation of biomass to liquid fuel, in the chemical industry, metallurgy, the food-processing industry etc.). For these conditions basic new technological solutions are offered. The main condition of their implementation is raise of hydrogen concentration in the sodium coolant on two – three order in comparison with the modern NPP, in a combination to hydrogen removal from sodium and its pumping out through membranes from vanadium or niobium. The researches with use diffusive model have shown possibility to expel a casium inflow in sodium through a leakproof shell of fuel rods if vary such parameters as a material of fuel rods shell, its thickness and maintenance time at design of fuel rods for high-temperature NPP. However maintenance of high-temperature NPP in the presence of casium in sodium is inevitable at loss of leakproof of a fuel rods shell. In these conditions for minimisation of casium diffusion in structural materials it is necessary to provide deep clearing of sodium from cesium.

  20. Computational assessment of several hydrogen-free high energy compounds.

    Science.gov (United States)

    Tan, Bisheng; Huang, Ming; Long, Xinping; Li, Jinshan; Fan, Guijuan

    2016-01-01

    Tetrazino-tetrazine-tetraoxide (TTTO) is an attractive high energy compound, but unfortunately, it is not yet experimentally synthesized so far. Isomerization of TTTO leads to its five isomers, bond-separation energies were empolyed to compare the global stability of six compounds, it is found that isomer 1 has the highest bond-separation energy (1204.6kJ/mol), compared with TTTO (1151.2kJ/mol); thermodynamic properties of six compounds were theoretically calculated, including standard formation enthalpies (solid and gaseous), standard fusion enthalpies, standard vaporation enthalpies, standard sublimation enthalpies, lattice energies and normal melting points, normal boiling points; their detonation performances were also computed, including detonation heat (Q, cal/g), detonation velocity (D, km/s), detonation pressure (P, GPa) and impact sensitivity (h50, cm), compared with TTTO (Q=1311.01J/g, D=9.228km/s, P=40.556GPa, h50=12.7cm), isomer 5 exhibites better detonation performances (Q=1523.74J/g, D=9.389km/s, P=41.329GPa, h50= 28.4cm). Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Biologically Induced Hydrogen Production Drives High Rate/High Efficiency Microbial Electrosynthesis of Acetate from Carbon Dioxide

    NARCIS (Netherlands)

    Jourdin, Ludovic; Lu, Yang; Flexer, Victoria; Keller, Jurg; Freguia, Stefano

    2016-01-01

    Electron-transfer pathways occurring in biocathodes are still unknown. We demonstrate here that high rates of acetate production by microbial electrosynthesis are mainly driven by an electron flux from the electrode to carbon dioxide, occurring via biologically induced hydrogen, with (99±1)%

  2. Study of hydrogen in coals, polymers, oxides, and muscle water by nuclear magnetic resonance; extension of solid-state high-resolution techniques. [Hydrogen molybdenum bronze

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, L.M.

    1981-10-01

    Nuclear magnetic resonance (NMR) spectroscopy has been an important analytical and physical research tool for several decades. One area of NMR which has undergone considerable development in recent years is high resolution NMR of solids. In particular, high resolution solid state /sup 13/C NMR spectra exhibiting features similar to those observed in liquids are currently achievable using sophisticated pulse techniques. The work described in this thesis develops analogous methods for high resolution /sup 1/H NMR of rigid solids. Applications include characterization of hydrogen aromaticities in fossil fuels, and studies of hydrogen in oxides and bound water in muscle.

  3. Enzyme-Mimetic Antioxidant Luminescent Nanoparticles for Highly Sensitive Hydrogen Peroxide Biosensing.

    Science.gov (United States)

    Pratsinis, Anna; Kelesidis, Georgios A; Zuercher, Stefanie; Krumeich, Frank; Bolisetty, Sreenath; Mezzenga, Raffaele; Leroux, Jean-Christophe; Sotiriou, Georgios A

    2017-12-26

    Hydrogen peroxide (H2O2) is an abundant molecule associated with biological functions and reacts with natural enzymes, such as catalase. Even though direct H2O2 measurement can be used to diagnose pathological conditions, such as infection and inflammation, H2O2 quantification further enables the detection of disease biomarkers in enzyme-linked assays (e.g., ELISA) in which enzymatic reactions may generate or consume H2O2. Such a quantification is often measured optically with organic dyes in biological media that suffer, however, from poor stability. Currently, the optical H2O2 biosensing without organic-dyes in biological media and at low, submicromolar, concentrations has yet to be achieved. Herein, we rationally design biomimetic artificial enzymes based on antioxidant CeO2 nanoparticles that become luminescent upon their Eu3+ doping. We vary systematically their diameter from 4 to 16 nm and study their catalase-mimetic antioxidant activity, manifested as catalytic H2O2 decomposition in aqueous solutions, revealing a strong nanoparticle surface area dependency. The interaction with H2O2 influences distinctly the particle luminescence rendering them highly sensitive H2O2 biosensors down to 0.15 μM (5.2 ppb) in solutions for biological assays. Our results link two, so far, unrelated research domains, the CeO2 nanoparticle antioxidant activity and luminescence by rare-earth doping. When these enzyme-mimetic nanoparticles are coupled with alcohol oxidase, biosensing can be extended to ethanol exemplifying how their detection potential can be broadened to additional biologically relevant metabolites. The enzyme-mimetic nanomaterial developed here could serve as a starting point of sophisticated in vitro assays toward the highly sensitive detection of disease biomarkers.

  4. High Pressure Hydrogen Pressure Relief Devices: Accelerated Life Testing and Application Best Practices

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, Robert M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Post, Matthew B. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Buttner, William J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rivkin, Carl H. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-11-06

    Pressure relief devices (PRDs ) are used to protect high pressure systems from burst failure caused by overpressurization. Codes and standards require the use of PRDs for the safe design of many pressurized systems. These systems require high reliability due to the risks associated with a burst failure. Hydrogen service can increase the risk of PRD failure due to material property degradation caused by hydrogen attack. The National Renewable Energy Laboratory (NREL) has conducted an accelerated life test on a conventional spring loaded PRD. Based on previous failures in the field, the nozzles specific to these PRDs are of particular interest. A nozzle in a PRD is a small part that directs the flow of fluid toward the sealing surface to maintain the open state of the valve once the spring force is overcome. The nozzle in this specific PRD is subjected to the full tensile force of the fluid pressure. These nozzles are made from 440C material, which is a type of hardened steel that is commonly chosen for high pressure applications because of its high strength properties. In a hydrogen environment, however, 440C is considered a worst case material since hydrogen attack results in a loss of almost all ductility and thus 440C is prone to fatigue and material failure. Accordingly, 440C is not recommended for hydrogen service. Conducting an accelerated life test on a PRD with 440C material provides information on necessary and sufficient conditions required to produce crack initiation and failure. The accelerated life test also provides information on other PRD failure modes that are somewhat statistically random in nature.

  5. Influence of high flux hydrogen-plasma exposure on the thermal shock induced crack formation in tungsten

    NARCIS (Netherlands)

    Wirtz, M.; Linke, J.; Pintsuk, G.; Rapp, J.; Wright, G. M.

    2012-01-01

    The influence of high flux hydrogen-plasma on the thermal shock behaviour of tungsten was investigated in a combined experiment using the linear plasma device Pilot-PSI and the electron beam facility JUDITH 1. Tungsten targets were exposed to high flux hydrogen plasma, cyclic thermal shock tests and

  6. Optimal design of high concentration reflected photovoltaic module

    Science.gov (United States)

    Hsu, Cheng-Yi; Lin, Yuli

    2017-09-01

    In this study, a fabrication and design process of a high concentration reflected photovoltaic (HCRPV) using 3x3 array modules with the light guide tube and III-V solar cells are demonstrated. The developed and designed of 3x3 array modules with the light guide tube following key design aims are all satisfied with highly uniform irradiance on the solar cell absorber and maximum light collective efficiency. With the use of the maximum peak power output from the tracking system which had two phases of X-Y axis and θ-axis tracking the sun position precisely and getting. With an optimized high concentration reflected photovoltaic systems of 3x3 array modules with the light guide tube, the optimal condition and measured characteristics and efficiency was conducted. This improved HCRPV performance is attributed to the enhanced collection light power from a big reflected mirror area. The HCRPV module was then fabricated using Aluminum material and it was coated with silver material. From the simulation results, the light collective efficiency can be reached to about 94.9% with uniform irradiance. From the measurement results, the power can be calculated to be 2.62W˜2.74W, which is about 90% of the power of solar cell (3W) used.

  7. Mapping Global Atmospheric CO2 Concentration at High Spatiotemporal Resolution

    Directory of Open Access Journals (Sweden)

    Yingying Jing

    2014-11-01

    Full Text Available Satellite measurements of the spatiotemporal distributions of atmospheric CO2 concentrations are a key component for better understanding global carbon cycle characteristics. Currently, several satellite instruments such as the Greenhouse gases Observing SATellite (GOSAT, SCanning Imaging Absorption Spectrometer for Atmospheric CHartographY (SCIAMACHY, and Orbiting Carbon Observatory-2 can be used to measure CO2 column-averaged dry air mole fractions. However, because of cloud effects, a single satellite can only provide limited CO2 data, resulting in significant uncertainty in the characterization of the spatiotemporal distribution of atmospheric CO2 concentrations. In this study, a new physical data fusion technique is proposed to combine the GOSAT and SCIAMACHY measurements. On the basis of the fused dataset, a gap-filling method developed by modeling the spatial correlation structures of CO2 concentrations is presented with the goal of generating global land CO2 distribution maps with high spatiotemporal resolution. The results show that, compared with the single satellite dataset (i.e., GOSAT or SCIAMACHY, the global spatial coverage of the fused dataset is significantly increased (reaching up to approximately 20%, and the temporal resolution is improved by two or three times. The spatial coverage and monthly variations of the generated global CO2 distributions are also investigated. Comparisons with ground-based Total Carbon Column Observing Network (TCCON measurements reveal that CO2 distributions based on the gap-filling method show good agreement with TCCON records despite some biases. These results demonstrate that the fused dataset as well as the gap-filling method are rather effective to generate global CO2 distribution with high accuracies and high spatiotemporal resolution.

  8. Experimental study and modeling of a high-temperature solar chemical reactor for hydrogen production from methane cracking

    Energy Technology Data Exchange (ETDEWEB)

    Abanades, Stephane; Flamant, Gilles [Processes, Materials, and Solar Energy Laboratory, CNRS (PROMES-CNRS, UPR 8521), 7 Rue du Four Solaire, 66120 Odeillo Font-Romeu (France)

    2007-07-15

    A high-temperature fluid-wall solar reactor was developed for the production of hydrogen from methane cracking. This laboratory-scale reactor features a graphite tubular cavity directly heated by concentrated solar energy, in which the reactive flowing gas dissociates to form hydrogen and carbon black. The solar reactor characterization was achieved with: (a) a thorough experimental study on the reactor performance versus operating conditions and (b) solar reactor modeling. The results showed that the conversion of CH{sub 4} and yield of H{sub 2} can exceed 97% and 90%, respectively, and these depend strongly on temperature and on fluid-wall heat transfer and reaction surface area. In addition to the experimental study, a 2D computational model coupling transport phenomena was developed to predict the mapping of reactor temperature and of species concentration, and the reaction extent at the outlet. The model was validated and kinetics of methane decomposition were identified from simulations and comparison to experimental results. (author)

  9. High resolution measurements and modeling of auroral hydrogen emission line profiles

    Directory of Open Access Journals (Sweden)

    B. S. Lanchester

    2003-07-01

    Full Text Available Measurements in the visible wavelength range at high spectral resolution (1.3 Å have been made at Longyearbyen, Svalbard (15.8 E,78.2 N during an interval of intense proton precipitation. The shape and Doppler shift of hydrogen Balmer beta line profiles have been compared with model line profiles, using as input ion energy spectra from almost coincident passes of the FAST and DMSP spacecraft. The comparison shows that the simulation contains the important physical processes that produce the profiles, and confirms that measured changes in the shape and peak wave-length of the hydrogen profiles are the result of changing energy input. This combination of high resolution measurements with modeling provides a method of estimating the incoming energy and changes in flux of precipitating protons over Svalbard, for given energy and pitch-angle distributions. Whereas for electron precipitation, information on the incident particles is derived from brightness and brightness ratios which require at least two spectral windows, for proton precipitation the Doppler profile of resulting hydrogen emission is directly related to the energy and energy flux of the incident energetic protons and can be used to gather information about the source region. As well as the expected Doppler shift to shorter wavelengths, the measured profiles have a significant red-shifted component, the result of upward flowing emitting hydrogen atoms.Key words. Ionosphere (auroral ionosphere; particle precipitation – Magnetospheric physics (auroral phenomena

  10. Effect of high soil copper concentration on mycorrhizal grapevines

    Science.gov (United States)

    Nogales, Amaia; Santos, Erika S.; Viegas, Wanda; Aran, Diego; Pereira, Sofia H.; Vidigal, Patricia; Lopes, Carlos M.; Abreu, M. Manuela

    2017-04-01

    Repeated application of Copper (Cu) based fungicides in vineyards since the end of the 19th century has led to a significant increase in the concentration of this chemical element in many viticultural soils. Although Cu is an essential micronutrient for most organisms, it can be toxic for the development and survival of plants and soil (micro)organisms at high concentrations and eventually lead to yield loses in viticulture, as it negatively affects key physiological and biogeochemical processes. However, some soil microorganisms, including arbuscular mycorrhizal fungi (AMF), have developed adaptive mechanisms for persistence in environments with supra-optimal levels of essential elements or in the presence of harmful ones, as well as for increasing plant tolerance to such abiotic stress conditions. The objective of this work was to evaluate the effect of a high total soil concentration of Cu on microbial soil activity as well as on the development of mycorrhizal and non-mycorrhizal grapevines. A microcosm assay was set up under greenhouse and controlled conditions. Touriga Nacional grapevine variety plants grafted onto 1103P rootstocks were inoculated either with the AMF Rhizophagus irregularis or Funneliformis mosseae, or were left as non-inoculated controls. After three months, they were transplanted to containers filled with 4 kg of a sandy soil (pH: 7.0; electrical conductivity: 0.08 mS/cm; [organic C]: 5.6 g/kg; [N-NO3]: 1.1 mg/kg; [N-NH4]: 2.5 mg/kg; [extractable K]: 45.1 mg/kg; [extractable P]: 52.3 mg/kg), collected near to a vineyard in Pegões (Portugal). Two treatments were carried out: with and without Cu application. The soil with high Cu concentration was prepared by adding 300 mg Cu/kg (in the form of an aqueous solution of CuSO4·5H2O) followed by an incubation during four weeks in plastic bags at room temperature in dark. Physico-chemical soil characteristics (pH, electrical conductivity and nutrients concentration in available fraction), soil

  11. Influence of the concentration of borohydride towards hydrogen production and escape for borohydride oxidation reaction on Pt and Au electrodes - experimental and modelling insights

    Science.gov (United States)

    Olu, Pierre-Yves; Bonnefont, Antoine; Braesch, Guillaume; Martin, Vincent; Savinova, Elena R.; Chatenet, Marian

    2018-01-01

    The Borohydride Oxidation Reaction (BOR), the anode reaction in a Direct borohydride fuel cell (DBFC), is complex and still poorly understood, which impedes the development and deployment of the DBFC technology. In particular, no practical electrocatalyst is capable to prevent gaseous hydrogen generation and escape from its anode upon operation, which lowers the fuel-efficiency of the DBFC and raises safety issues in operation. The nature of the anode electrocatalysts strongly influences the hydrogen escape characteristics of the DBFC, which demonstrates how important it is to isolate the BOR mechanism in conditions relevant to DBFC operation. In this paper, from a selected literature review and BOR experiments performed in differential electrochemical mass spectrometry (DEMS) in a wide range of NaBH4 concentration (5-500 mM), a microkinetic model of the BOR for both Pt and Au surfaces is proposed; this model takes into account the hydrogen generation and escape.

  12. Kinetic modeling of hydrogen production rate by photoautotrophic cyanobacterium A. variabilis ATCC 29413 as a function of both CO2 concentration and oxygen production rate.

    Science.gov (United States)

    Salleh, Siti Fatihah; Kamaruddin, Azlina; Uzir, Mohamad Hekarl; Mohamed, Abdul Rahman; Shamsuddin, Abdul Halim

    2017-02-07

    Hydrogen production by cyanobacteria could be one of the promising energy resources in the future. However, there is very limited information regarding the kinetic modeling of hydrogen production by cyanobacteria available in the literature. To provide an in-depth understanding of the biological system involved during the process, the Haldane's noncompetitive inhibition equation has been modified to determine the specific hydrogen production rate (HPR) as a function of both dissolved CO2 concentration (CTOT) and oxygen production rate (OPR). The highest HPR of 15 [Formula: see text] was found at xCO2 of 5% vol/vol and the rate consequently decreased when the CTOT and OPR were 0.015 k mol m(-3) and 0.55 mL h(-1), respectively. The model provided a fairly good estimation of the HPR with respect to the experimental data collected.

  13. Unexpectedly high ultrafine aerosol concentrations above East Antarctic sea ice

    Directory of Open Access Journals (Sweden)

    R. S. Humphries

    2016-02-01

    Full Text Available Better characterisation of aerosol processes in pristine, natural environments, such as Antarctica, have recently been shown to lead to the largest reduction in uncertainties in our understanding of radiative forcing. Our understanding of aerosols in the Antarctic region is currently based on measurements that are often limited to boundary layer air masses at spatially sparse coastal and continental research stations, with only a handful of studies in the vast sea-ice region. In this paper, the first observational study of sub-micron aerosols in the East Antarctic sea ice region is presented. Measurements were conducted aboard the icebreaker Aurora Australis in spring 2012 and found that boundary layer condensation nuclei (CN3 concentrations exhibited a five-fold increase moving across the polar front, with mean polar cell concentrations of 1130 cm−3 – higher than any observed elsewhere in the Antarctic and Southern Ocean region. The absence of evidence for aerosol growth suggested that nucleation was unlikely to be local. Air parcel trajectories indicated significant influence from the free troposphere above the Antarctic continent, implicating this as the likely nucleation region for surface aerosol, a similar conclusion to previous Antarctic aerosol studies. The highest aerosol concentrations were found to correlate with low-pressure systems, suggesting that the passage of cyclones provided an accelerated pathway, delivering air masses quickly from the free troposphere to the surface. After descent from the Antarctic free troposphere, trajectories suggest that sea-ice boundary layer air masses travelled equatorward into the low-albedo Southern Ocean region, transporting with them emissions and these aerosol nuclei which, after growth, may potentially impact on the region's radiative balance. The high aerosol concentrations and their transport pathways described here, could help reduce the discrepancy currently present between

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

    Energy Technology Data Exchange (ETDEWEB)

    Way, J. Douglas [Colorado School of Mines, Golden, CO (United States). Dept. of Chemical and Biological Engineering; Wolden, Colin A. [Colorado School of Mines, Golden, CO (United States)

    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 Mo2C 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 Mo2C surface diffusion membrane achieved a pure hydrogen flux of 367 SCFH/ft2 at a feed pressure of only 20 psig. The highest H2/N2 selectivity obtained with this approach was 4.9. A transport model using “dusty gas” theory was derived to describe the hydrogen transport in the Mo2C 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) Mo2C catalyst layers. We have fabricated a Mo2C/V composite membrane that in pure gas testing delivered a H2 flux of 238 SCFH/ft2 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/ft2.psi. However, during testing of a Mo2C coated Pd alloy membrane with DOE 1 feed gas mixture a hydrogen permeance of >2 SCFH/ft2.psi was obtained which was stable during the entire test, meeting the permeance associated with

  15. High manganese concentrations in rocks at Gale crater, Mars

    Science.gov (United States)

    Lanza, Nina L.; Fischer, Woodward W.; Wiens, Roger C.; Grotzinger, John P.; Ollila, Ann M.; Anderson, Ryan B.; Clark, Benton C.; Gellert, Ralf; Mangold, Nicolas; Maurice, Sylvestre; Le Mouélic, Stéphane; Nachon, Marion; Schmidt, Mariek E.; Berger, Jeffrey; Clegg, Samuel M.; Forni, Olivier; Hardgrove, Craig; Melikechi, Noureddine; Newsom, Horton E.; Sautter, Violaine

    2014-01-01

    The surface of Mars has long been considered a relatively oxidizing environment, an idea supported by the abundance of ferric iron phases observed there. However, compared to iron, manganese is sensitive only to high redox potential oxidants, and when concentrated in rocks, it provides a more specific redox indicator of aqueous environments. Observations from the ChemCam instrument on the Curiosity rover indicate abundances of manganese in and on some rock targets that are 1–2 orders of magnitude higher than previously observed on Mars, suggesting the presence of an as-yet unidentified manganese-rich phase. These results show that the Martian surface has at some point in time hosted much more highly oxidizing conditions than has previously been recognized.

  16. Numerical Modeling of the Stability of Face-Centered Cubic Metals with High Vacancy Concentration

    Energy Technology Data Exchange (ETDEWEB)

    Brian P. Somerday; M. I. Baskes

    1998-12-01

    The objective of this research is to assess the possibility of forming an atomically porous structure in a low-density metal, e.g., Al with vacancies up to 0.20/lattice site; and to examine the effects of hydrogen and vacancy concentration on the stability of an atomically porous structure that has been experimentally produced in nickel. The approach involves numerical modeling using the Embedded-Atom Method (EAM). High vacancy concentrations cause the Al lattice to disorder at 300K. In contrast, Ni retains the face-centered-cubic structure at 300K for vacancy concentrations up to 0.15 Vac/lattice site. Unexpectedly, the lattice with 0.15 Vac/lattice site is more stable than the lattice with 0.10 or 0.20 Vac/lattice site. The Ni systems with 0.10 and 0.15 Vac/lattice site exhibit domains consisting of uniform lattice rotations. The Ni lattice with 0.15 Vac/lattice site is more stable with an initial distribution of random vacancies compared to ordered vacancies. The equilibrium lattice structures of Ni a d Al containing vacancies and H are less ordered to structures with vacancies only at 300K.

  17. In operando visualization of hydride-graphite composites during cyclic hydrogenation by high-resolution neutron imaging

    Science.gov (United States)

    Pohlmann, Carsten; Herbrig, Kai; Gondek, Łukasz; Kardjilov, Nikolay; Hilger, André; Figiel, Henryk; Banhart, John; Kieback, Bernd; Manke, Ingo; Röntzsch, Lars

    2015-03-01

    Hydrogen solid-state storage in metal hydrides has attracted remarkable attention within the past decades due to their high volumetric storage densities at low operating pressures. In particular, recently emerged hydride-graphite composites (HGC) can enable a safe, reliable and very compact hydrogen storage solution for various applications. In this regard, only little is known about the activation behavior of such HGC, their cycle stability and degradation effects. Because of the high sensitivity to hydrogen, neutron imaging offers a distinctive approach to examine in operando reaction fronts, swelling effects and microstructural changes of hydrogen absorbing materials with high spatial and temporal resolution. In this contribution, a comprehensive analysis of various phenomena during activation and cycling of HGC based on a Ti-Mn hydrogen absorbing alloy and expanded natural graphite is reported for the first time. A neutron radiography and tomography set-up with a spatial resolution down to 7 μm was utilized allowing highest detection precision. During initial hydrogenation, regions with enhanced reactivity are observed which contradicts a theoretically expected homogeneous reactivity inside the HGC. These active regions grow with the number of hydrogenation-dehydrogenation cycles until the whole HGC volume uniformly participates in the hydrogen sorption reaction. With regard to long-term hydrogenation-dehydrogenation cycling, inhomogeneous swelling effects were observed from which essential conclusions for technical HGC-based tank systems can be derived.

  18. A comparison of hydrogen ion concentration and pH genetic predictions and fixed effect estimations when assessing pork quality.

    Science.gov (United States)

    Stalder, K J; Saxton, A M; Miller, R K; Goodwin, R N

    2003-03-01

    An evaluation of ultimate pH (pH) and hydrogen ion concentration (H+) was conducted to determine if the mathematical conversion of H+ to pH could affect 1. fixed and random effect inferences and 2. prediction of genetic merit of animals when either pH or H+ is used as an indicator in the assessment of pork quality. Data from 4,262 purebred animals and 577 sires having complete three-generation pedigrees from the 1991 to 2001 National Barrow Show Progeny Tests were utilized in this study. Existing loin muscle pH data were converted to their original H+. Numerical changes in values occurred across all fixed effects and in the case of breed and test, changes in differences among subclasses occurred. These changes may result in differing inferences that can be made depending on whether pH or H+ is used as the dependent variable. Heritability estimates for pH and H+ were 0.52 +/- 0.074 and 0.62 +/- 0.078, respectively. The Pearson correlation between pH and H+ breeding values was -0.92. Spearman Rank correlation of -0.91 between pH and H+ breeding values was calculated and indicates that sires do not rank the same when ordered by breeding values for each trait. When pH is the selection objective, the selection differential reduction in H+ from these data ranges from 3.8 to 9.1%. Additionally, only 77.7% of the estimated genetic progress per generation in H+ is realized when selection (5% selected) is based on pH. The genetic correlation between pH and H+ was -0.96. Changes in the absolute values of the genetic correlations between various pork quality indicator traits and pH or H+ concentration were 0.04 or less. Differences in pH and H+ results could impact decisions made by swine breeders and meat processors who are concerned about pork quality. This, combined with the greater heritability and biochemical reality for H+, indicates that H+ rather than pH is the more appropriate trait breeders and processors should focus on when attempting to improve pork quality.

  19. Hydrogen production from high-moisture content biomass in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Antal, M.J. Jr.; Adschiri, T.; Ekbom, T. [Univ. of Hawaii, Honolulu, HI (United States)] [and others

    1996-10-01

    Most hydrogen is produced by steam reforming methane at elevated pressures. The goal of this research is to develop commercial processes for the catalytic steam reforming of biomass and other organic wastes at high pressures. This approach avoids the high cost of gas compression and takes advantage of the unique properties of water at high pressures. Prior to this year the authors reported the ability of carbon to catalyze the decomposition of biomass and related model compounds in supercritical water. The product gas consists of hydrogen, carbon dioxide, carbon monoxide, methane, and traces of higher hydrocarbons. During the past year the authors have: (a) developed a method to extend the catalyst life, (b) begun studies of the role of the shift reaction, (c) completed studies of carbon dioxide absorption from the product effluent by high pressure water, (d) measured the rate of carbon catalyst gasification in supercritical water, (e) discovered the pumpability of oil-biomass slurries, and (f) completed the design and begun fabrication of a flow reactor that will steam reform whole biomass feedstocks (i.e. sewage sludge) and produce a hydrogen rich synthesis gas at very high pressure (>22 MPa).

  20. Highly Selective TiN-Supported Highly Dispersed Pt Catalyst: Ultra Active toward Hydrogen Oxidation and Inactive toward Oxygen Reduction.

    Science.gov (United States)

    Luo, Junming; Tang, Haibo; Tian, Xinlong; Hou, Sanying; Li, Xiuhua; Du, Li; Liao, Shijun

    2018-01-31

    The severe dissolution of the cathode catalyst, caused by an undesired oxygen reduction reaction at the anode during startup and shutdown, is a fatal challenge to practical applications of polymer electrolyte membrane fuel cells. To address this important issue, according to the distinct structure-sensitivity between the σ-type bond in H 2 and the π-type bond in O 2 , we design a HD-Pt/TiN material by highly dispersing Pt on the TiN surface to inhibit the unwanted oxygen reduction reaction. The highly dispersed Pt/TiN catalyst exhibits excellent selectivity toward hydrogen oxidation and oxygen reduction reactions. With a Pt loading of 0.88 wt %, our catalyst shows excellent hydrogen oxidation reaction activity, close to that of commercial 20 wt % Pt/C catalyst, and much lower oxygen reduction reaction activity than the commercial 20 wt % Pt/C catalyst. The lack of well-ordered Pt facets is responsible for the excellent selectivity of the HD-Pt/TiN materials toward hydrogen oxidation and oxygen reduction reactions. Our work provides a new and cost-effective solution to design selective catalysts toward hydrogen oxidation and oxygen reduction reactions, making the strategy of using oxygen-tolerant anode catalyst to improve the stability of polymer electrolyte membrane fuel cells during startup and shutdown more affordable and practical.

  1. Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cells - An update

    Science.gov (United States)

    Smithrick, John J.; Hall, Stephen W.

    An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent potassium hydroxide (KOH) electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen cells is reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH.

  2. AN EVALUATION OF HYDROGEN INDUCED CRACKING SUSCEPTIBILITY OF TITANIUM ALLOYS IN US HIGH-LEVEL NUCLEAR WASTE REPOSITORY ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    G. De; K. Mon; G. Gordon; D. Shoesmith; F. Hua

    2006-02-21

    This paper evaluates hydrogen-induced cracking (HIC) susceptibility of titanium alloys in environments anticipated in the Yucca Mountain nuclear waste repository with particular emphasis on the. effect of the oxide passive film on the hydrogen absorption process of titanium alloys being evaluated. The titanium alloys considered in this review include Ti 2, 5 , 7, 9, 11, 12, 16, 17, 18, 24 and 29. In general, the concentration of hydrogen in a titanium alloy can increase due to absorption of atomic hydrogen produced from passive general corrosion of that alloy or galvanic coupling of it to a less noble metal. It is concluded that under the exposure conditions anticipated in the Yucca Mountain repository, the HIC of titanium drip shield will not occur because there will not be sufficient hydrogen in the metal even after 10,000 years of emplacement. Due to the conservatisms adopted in the current evaluation, this assessment is considered very conservative.

  3. Hydrogen sulfide suppresses high glucose-induced expression of intercellular adhesion molecule-1 in endothelial cells.

    Science.gov (United States)

    Guan, Qingbo; Wang, Xiaolei; Gao, Ling; Chen, Jicui; Liu, Yuantao; Yu, Chunxiao; Zhang, Nan; Zhang, Xu; Zhao, Jiajun

    2013-09-01

    Hydrogen sulfide (H₂S) is a newly identified endogenous gasotransmitter that has been implicated in the pathophysiology of several biologic systems. However, the role of H₂S in the pathogenesis of diabetic vascular injury remains unclear. The aims of this study were to determine the effect of H₂S on the high glucose (HG)-induced expression of intercellular adhesion molecule-1 (ICAM-1) in human umbilical vein endothelial cells and to explore the possible underlying mechanisms. Human umbilical vein endothelial cells were exposed either to a normal concentration of D-glucose (5.5 mmol/L) or to HG (16.7 mmol/L) in the absence or presence of NaHS for the indicated periods. The ICAM-1 protein and messenger RNA (mRNA) levels were analyzed by Western blotting and real-time reverse transcriptase-polymerase chain reaction, respectively. Exposure to HG for 48 or 72 hours significantly increased ICAM-1 expression at both the protein and mRNA levels, and these increases correlated with increases in both the production of intracellular reactive oxygen species and the activation of nuclear factor-κB. Pretreatment with NaHS inhibited HG-induced ICAM-1 expression at both the protein and mRNA levels and resulted in a reduction in the intracellular reactive oxygen species level and the suppression of nuclear factor-κB activity. NaHS also inhibited tumor necrosis factor-α-induced ICAM-1 protein expression, which was similar to the effect of antioxidant N-acetyl-L-cysteine. These findings indicate that H₂S might protect against HG-induced vascular damage by down-regulating ICAM-1 expression in endothelial cells.

  4. Localised, high-speed flows within the hydrogen-deficient planetary nebula Abell 78

    Science.gov (United States)

    Meaburn, J.; Lopez, J. A.; Bryce, M.; Redman, M. P.

    1998-06-01

    The remarkable velocity structure of the different components of the hydrogen-deficient planetary nebula Abell 78 have been revealed by obtaining spatially resolved profiles of the [O i] 6300 Angstromsii\\ line with the Manchester echelle spectrometer combined with the 2.1 m San Pedro Martir telescope. The outer, diffuse, hydrogen-rich, 124'' diameter shell is expanding radially at 40 km s^{-1}$. The irregular, knotty, hydrogen-deficient 89arcsec \\times 52arcsec \\ inner shell has a similar overall expansion velocity but more complex kinematical structure. Similar to A 30, velocity `spikes' are found in the position-velocity arrays of [O {sc i}] 6300 Angstromsii\\ profiles from the inner shell. These extend to a further -140 km s^{-1} than the radial velocity of the approaching side of this inner shell. The [O {sc i}] 6300 Angstromsii\\ bright, hydrogen-deficient core knots are distributed throughout an elongated disk expanding at \\approx 25 km s^{-1}. There is kinematical evidence that `polar bullets' are being ejected perpendicularly to this central feature at 380 km s^{-1}. Altogether `velocity spikes' and other high-speed knots in the pv arrays of [O {sc i}] 6300 Angstromsii\\ profiles are found over a 455 km s^{-1}$ range of radial velocities. Many of the kinematical phenomena are considered to be a consequence of the mass-loaded, shocked, wind from the central star.

  5. Transient flow in pipelines of high-pressure hydrogen-natural gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Elaoud, Sami; Hadj-Taieb, Ezzeddine [Unit of Applied Fluid Mechanics and Modeling, ENIS, Sokra Road Km 4, P.O. Box W, Sfax 3038 (Tunisia)

    2008-09-15

    The purpose of this study is the numerical modeling of high-pressure transient flow of hydrogen-natural gas mixtures in rigid pipelines. The governing equations for such flows are two coupled, non-linear, hyperbolic, partial differential equations. The fluid pressure and velocity are considered as two principal dependent variables. The fluid is a homogeneous hydrogen-natural gas mixture for which the density is defined by an expression averaging the two gas densities where a polytropic process is admitted for the two components. The hydrogen-mixture mass ratio (or quality), assumed to be constant, is used in the mathematical formulation, instead of the void fraction which varies with pressure. The problem has been solved by the non-linear method of characteristics and the finite difference conservative method. To verify their validity, the computed results of the two numerical methods are compared for different values of the quality. The occurrence of pressure oscillations in hydrogen-natural gas mixture pipelines was studied as a result of the compression wave created by a rapid closure of downstream shut-off valve. (author)

  6. An in situ tribometer for measuring friction and wear of polymers in a high pressure hydrogen environment

    Science.gov (United States)

    Duranty, Edward R.; Roosendaal, Timothy J.; Pitman, Stan G.; Tucker, Joseph C.; Owsley, Stanley L.; Suter, Jonathan D.; Alvine, Kyle J.

    2017-09-01

    High pressure hydrogen effects on the friction and wear of polymers are of importance to myriad applications. Of special concern are those used in the infrastructure for hydrogen vehicle refueling stations, including compressor sliding seals, valves, and actuators. While much is known about potentially damaging embrittlement effects of hydrogen on metals, relatively little is known about the effects of high pressure hydrogen on polymers. However, based on the limited results that are published in the literature, polymers also apparently exhibit compatibility issues with hydrogen. An additional study is needed to elucidate these effects to avoid incompatibilities either through design or material selection. As part of this effort, we present here in situ high pressure hydrogen studies of the friction and wear on example polymers. To this end, we have built and demonstrated a custom-built pin-on-flat linear reciprocating tribometer and demonstrated its use with in situ studies of friction and wear behavior of nitrile butadiene rubber polymer samples in 28 MPa hydrogen. Tribology results indicate that friction and wear is increased in high pressure hydrogen as compared both with values measured in high pressure argon and ambient air conditions.

  7. Highly Active, Nonprecious Electrocatalyst Comprising Borophene Subunits for the Hydrogen Evolution Reaction.

    Science.gov (United States)

    Chen, Yanli; Yu, Guangtao; Chen, Wei; Liu, Yipu; Li, Guo-Dong; Zhu, Pinwen; Tao, Qiang; Li, Qiuju; Liu, Jingwei; Shen, Xiaopeng; Li, Hui; Huang, Xuri; Wang, Dejun; Asefa, Tewodros; Zou, Xiaoxin

    2017-09-13

    Developing nonprecious hydrogen evolution electrocatalysts that can work well at large current densities (e.g., at 1000 mA/cm2: a value that is relevant for practical, large-scale applications) is of great importance for realizing a viable water-splitting technology. Herein we present a combined theoretical and experimental study that leads to the identification of α-phase molybdenum diboride (α-MoB2) comprising borophene subunits as a noble metal-free, superefficient electrocatalyst for the hydrogen evolution reaction (HER). Our theoretical finding indicates, unlike the surfaces of Pt- and MoS2-based catalysts, those of α-MoB2 can maintain high catalytic activity for HER even at very high hydrogen coverage and attain a high density of efficient catalytic active sites. Experiments confirm α-MoB2 can deliver large current densities in the order of 1000 mA/cm2, and also has excellent catalytic stability during HER. The theoretical and experimental results show α-MoB2's catalytic activity, especially at large current densities, is due to its high conductivity, large density of efficient catalytic active sites and good mass transport property.

  8. Hydrogenated indium oxide window layers for high-efficiency Cu(In,Ga)Se{sub 2} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Jäger, Timo, E-mail: timo.jaeger@empa.ch; Romanyuk, Yaroslav E.; Nishiwaki, Shiro; Bissig, Benjamin; Pianezzi, Fabian; Fuchs, Peter; Gretener, Christina; Tiwari, Ayodhya N. [Empa – Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Thin Films and Photovoltaics, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Döbeli, Max [ETH Zürich, Swiss Federal Institute of Technology, Laboratory of Ion Beam Physics, Otto-Stern-Weg 5, 8093 Zürich (Switzerland)

    2015-05-28

    High mobility hydrogenated indium oxide is investigated as a transparent contact for thin film Cu(In,Ga)Se{sub 2} (CIGS) solar cells. Hydrogen doping of In{sub 2}O{sub 3} thin films is achieved by injection of H{sub 2}O water vapor or H{sub 2} gas during the sputter process. As-deposited amorphous In{sub 2}O{sub 3}:H films exhibit a high electron mobility of ∼50 cm{sup 2}/Vs at room temperature. A bulk hydrogen concentration of ∼4 at. % was measured for both optimized H{sub 2}O and H{sub 2}-processed films, although the H{sub 2}O-derived film exhibits a doping gradient as detected by elastic recoil detection analysis. Amorphous IOH films are implemented as front contacts in CIGS based solar cells, and their performance is compared with the reference ZnO:Al electrodes. The most significant feature of IOH containing devices is an enhanced open circuit voltage (V{sub OC}) of ∼20 mV regardless of the doping approach, whereas the short circuit current and fill factor remain the same for the H{sub 2}O case or slightly decrease for H{sub 2}. The overall power conversion efficiency is improved from 15.7% to 16.2% by substituting ZnO:Al with IOH (H{sub 2}O) as front contacts. Finally, stability tests of non-encapsulated solar cells in dry air at 80 °C and constant illumination for 500 h demonstrate a higher stability for IOH-containing devices.

  9. Li4FeH6: Iron-containing complex hydride with high gravimetric hydrogen density

    Directory of Open Access Journals (Sweden)

    Hiroyuki Saitoh

    2014-07-01

    Full Text Available Li4FeH6, which has the highest gravimetric hydrogen density of iron-containing complex hydrides reported so far, is synthesized by hydrogenation of a powder mixture of iron and LiH above 6.1 GPa at 900 °C. In situ synchrotron radiation X-ray diffraction measurements reveal that while kinetics require high temperature and thus high pressure for the synthesis, Li4FeH6 is expected to be thermodynamically stable slightly below room temperature at ambient pressure; further synthetic studies to suppress the kinetic effects may enable us to synthesize Li4FeH6 at moderate pressures. Li4FeH6 can be recovered at ambient conditions where Li4FeH6 is metastable.

  10. Seawater splitting for high-efficiency hydrogen evolution by alloyed PtNix electrocatalysts

    Science.gov (United States)

    Zheng, Jingjing

    2017-08-01

    Robust electrocatalyst is a prerequisite to realize high-efficiency hydrogen evolution by water splitting. Expensive platinum (Pt) is a preferred electrode catalyst for state-of-the-art hydrogen evolution reaction (HER). We present here a category of alloyed PtNix electrocatalysts by a facile green chemical reduction method, which are used to catalyze HER during seawater splitting. The catalytic performances are optimized by tuning stoichiometric Pt/Ni ratio, yielding a maximized catalytic behavior for PtNi5 electrode. The minimized onset potential is as low as -0.38 V and the corresponding Tafel slope is 119 mV dec-1. Moreover, the launched alloy electrodes have remarkable stability at -1.2 V over 12 h. The high efficiency as well as good durability demonstrates the PtNix electrocatalysts to be promising in practical applications.

  11. Surface plasmon resonance hydrogen sensor based on metallic grating with high sensitivity.

    Science.gov (United States)

    Lin, Kaiqun; Lu, Yonghua; Chen, Junxue; Zheng, Rongsheng; Wang, Pei; Ming, Hai

    2008-11-10

    High sensitivity is obtained at larger resonant incident angle if negative diffraction order of metallic grating is used to excite the surface plasmon. A highly sensitive grating-based surface plasmon resonance (SPR) sensor is designed for the hydrogen detection. A thin palladium (Pd) film deposited on the grating surface is used as transducer. The influences of grating period and the thickness of Pd on the performance of sensor are investigated using rigorous coupled-wave analysis (RCWA) method. The sensitivity as well as the width of the SPR curves and reflective amplitude is considered simultaneously for designing the grating-based SPR hydrogen sensor, and a set of optimized structural parameters is presented. The performance of grating-based SPR sensor is also compared with that of conventional prism-based SPR sensor.

  12. Turbojet Performance and Operation at High Altitudes with Hydrogen and Jp-4 Fuels

    Science.gov (United States)

    Fleming, W A; Kaufman, H R; Harp, J L , Jr; Chelko, L J

    1956-01-01

    Two current turbojet engines were operated with gaseous-hydrogen and JP-4 fuels at very high altitudes and a simulated Mach number of 0.8. With gaseous hydrogen as the fuel stable operation was obtained at altitudes up to the facility limit of about 90,000 feet and the specific fuel consumption was only 40 percent of that with JP-4 fuel. With JP-4 as the fuel combustion was unstable at altitudes above 60,000 to 65,000 feet and blowout limits were reached at 75,000 to 80,000 feet. Over-all performance, component efficiencies, and operating range were reduced considerable at very high altitudes with both fuels.

  13. Hydrogenated TiO2 nanobelts as highly efficient photocatalytic organic dye degradation and hydrogen evolution photocatalyst.

    Science.gov (United States)

    Tian, Jian; Leng, Yanhua; Cui, Hongzhi; Liu, Hong

    2015-12-15

    TiO2 nanobelts have gained increasing interest because of its outstanding properties and promising applications in a wide range of fields. Here we report the facile synthesis of hydrogenated TiO2 (H-TiO2) nanobelts, which exhibit excellent UV and visible photocatalytic decomposing of methyl orange (MO) and water splitting for hydrogen production. The improved photocatalytic property can be attributed to the Ti(3+) ions and oxygen vacancies in TiO2 nanobelts created by hydrogenation. Ti(3+) ions and oxygen vacancies can enhance visible light absorption, promote charge carrier trapping, and hinder the photogenerated electron-hole recombination. This work offers a simple strategy for the fabrication of a wide solar spectrum of active photocatalysts, which possesses significant potential for more efficient photodegradation, photocatalytic water splitting, and enhanced solar cells using sunlight as light source. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Single-catalyst high-weight% hydrogen storage in an N-heterocycle synthesized from lignin hydrogenolysis products and ammonia.

    Science.gov (United States)

    Forberg, Daniel; Schwob, Tobias; Zaheer, Muhammad; Friedrich, Martin; Miyajima, Nobuyoshi; Kempe, Rhett

    2016-10-20

    Large-scale energy storage and the utilization of biomass as a sustainable carbon source are global challenges of this century. The reversible storage of hydrogen covalently bound in chemical compounds is a particularly promising energy storage technology. For this, compounds that can be sustainably synthesized and that permit high-weight% hydrogen storage would be highly desirable. Herein, we report that catalytically modified lignin, an indigestible, abundantly available and hitherto barely used biomass, can be harnessed to reversibly store hydrogen. A novel reusable bimetallic catalyst has been developed, which is able to hydrogenate and dehydrogenate N-heterocycles most efficiently. Furthermore, a particular N-heterocycle has been identified that can be synthesized catalytically in one step from the main lignin hydrogenolysis product and ammonia, and in which the new bimetallic catalyst allows multiple cycles of high-weight% hydrogen storage.

  15. Characterization of blood donors with high haemoglobin concentration

    DEFF Research Database (Denmark)

    Magnussen, K; Hasselbalch, H C; Ullum, H

    2013-01-01

    Background and Objectives  The literature contains little on the prevalence and causes of high predonation haemoglobin levels among blood donors. This study aimed to characterize and develop an algorithm to manage would-be donors with polycythaemia. Materials and Methods  Between November 2009...... and November 2011, we offered haematology consultations to blood donors with repeated haemoglobin concentration (Hb) above the WHO limit for polycythaemia vera (PV) (10·2 and 11·5 mm/16·5 and 18·5 g/dl for women and men, respectively). Investigation of such donors included Hb, haematocrit, mean cell volume......, erythropoietin, ferritin, platelet count and leucocyte count, JAK2 V617 and JAK2 exon12 analysis, as well as other routine measurements. Results  Among 46 such donors, 39 had a history of smoking, which contributes to erythrocytosis. Two had PV, five had severe hypertension, one of them because of renal artery...

  16. Acquisition and Analysis of Data from High Concentration Solutions

    KAUST Repository

    Besong, Tabot M.D.

    2016-05-13

    The problems associated with ultracentrifugal analysis of macromolecular solutions at high (>10 mg/ml) are reviewed. Especially for the case of solutes which are non-monodisperse, meaningful results are not readily achievable using sedimentation velocity approaches. It is shown however by both simulation and analysis of practical data that using a modified form of an algorithm (INVEQ) published in other contexts, sedimentation equilibrium (SE) profiles can be analysed successfully, enabling topics such as oligomer presence or formation to be defined.To achieve this, it is necessary to employ an approach in which the solution density, which in an SE profile is radius-dependent, is taken into consideration. Simulation suggests that any reasonable level of solute concentration can be analysed.

  17. Quasi-two-dimensional metallic hydrogen inside di-phosphide at high pressure

    OpenAIRE

    Degtyarenko, Nikolay; Mazur, Evgeny

    2016-01-01

    The method of mathematical modeling was used for the calculation of the structural, electronic, phonon, and other characteristics of various normal phases of phosphorus hydrides with stoichiometry PHk. It was shown that the di-phosphine may form 2D lattice of the metallic hydrogen, stabilized by phosphorus atoms under high hydrostatic compressive pressure. The resulting structure with the elements of H-P-H is a locally stable one in the phonon spectrum (or metastable). The properties of di-ph...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. Coagulation pretreatment of highly concentrated acrylonitrile wastewater from petrochemical plants.

    Science.gov (United States)

    Zheng, Dongju; Qin, Lin; Wang, Tao; Ren, Xiaojing; Zhang, Zhongguo; Li, Jiding

    2014-01-01

    Acrylonitrile (AN) wastewater is a heavily polluted and a likely hazardous liquid that is generated during the production of AN. Several chemical methods for the pretreatment of AN wastewater are available in laboratory scale. However, the harsh reaction conditions and high operational cost make these methods undesirable. Until now, four-effect evaporation is the only pretreatment method used for AN wastewater in industry despite its huge energy consumption and high cost. It is difficult to find an energy-saving pretreatment technique from the perspective of industrial application. In this study, a safe and low-cost coagulation technique was developed for the pretreatment of AN wastewater. Three types of inorganic coagulant and three types of polymer coagulant were investigated for the coagulation treatment of highly concentrated AN wastewater from petrochemical plants. The effects of coagulant type, dosage, and coagulation conditions on the pretreatment efficiency of AN wastewater were investigated. The results show that a combination of inorganic and polymer coagulants is effective for the pretreatment of AN wastewater.

  20. Highly Concentrated Acetic Acid Poisoning: 400 Cases Reviewed

    Directory of Open Access Journals (Sweden)

    Konstantin Brusin

    2012-12-01

    Full Text Available Background: Caustic substance ingestion is known for causing a wide array of gastrointestinal and systemic complications. In Russia, ingestion of acetic acid is a major problem which annually affects 11.2 per 100,000 individuals. The objective of this study was to report and analyze main complications and outcomes of patients with 70% concentrated acetic acid poisoning. Methods: This was a retrospective study of patients with acetic acid ingestion who were treated at Sverdlovsk Regional Poisoning Treatment Center during 2006 to 2012. GI mucosal injury of each patient was assessed with endoscopy according to Zargar’s scale. Data analysis was performed to analyze the predictors of stricture formation and mortality. Results: A total of 400 patients with median age of 47 yr were included. GI injury grade I was found in 66 cases (16.5%, IIa in 117 (29.3%, IIb in 120 (30%, IIIa in 27 (16.7% and IIIb in 70 (17.5%. 11% of patients developed strictures and overall mortality rate was 21%. Main complications were hemolysis (55%, renal injury (35%, pneumonia (27% and bleeding during the first 3 days (27%. Predictors of mortality were age 60 to 79 years, grade IIIa and IIIb of GI injury, pneumonia, stages “I”, “F” and “L” of kidney damage according to the RIFLE scale and administration of prednisolone. Predictors of stricture formation were ingestion of over 100 mL of acetic acid and grade IIb and IIIa of GI injury. Conclusion: Highly concentrated acetic acid is still frequently ingested in Russia with a high mortality rate. Patients with higher grades of GI injury, pneumonia, renal injury and higher amount of acid ingested should be more carefully monitored as they are more susceptible to develop fatal consequences.          

  1. Diurnal changes in the xanthophyll cycle pigments of freshwater algae correlate with the environmental hydrogen peroxide concentration rather than non-photochemical quenching

    Science.gov (United States)

    Roach, Thomas; Miller, Ramona; Aigner, Siegfried; Kranner, Ilse

    2015-01-01

    Background and Aims In photosynthetic organisms exposure to high light induces the production of reactive oxygen species (ROS), such as hydrogen peroxide (H2O2), which in part is prevented by non-photochemical quenching (NPQ). As one of the most stable and longest-lived ROS, H2O2 is involved in key signalling pathways in development and stress responses, although in excess it can induce damage. A ubiquitous response to high light is the induction of the xanthophyll cycle, but its role in algae is unclear as it is not always associated with NPQ induction. The aim of this study was to reveal how diurnal changes in the level of H2O2 are regulated in a freshwater algal community. Methods A natural freshwater community of algae in a temporary rainwater pool was studied, comprising photosynthetic Euglena species, benthic Navicula diatoms, Chlamydomonas and Chlorella species. Diurnal measurements were made of photosynthetic performance, concentrations of photosynthetic pigments and H2O2. The frequently studied model organisms Chlamydomonas and Chlorella species were isolated to study photosynthesis-related H2O2 responses to high light. Key Results NPQ was shown to prevent H2O2 release in Chlamydomonas and Chlorella species under high light; in addition, dissolved organic carbon excited by UV-B radiation was probably responsible for a part of the H2O2 produced in the water column. Concentrations of H2O2 peaked at 2 µm at midday and algae rapidly scavenged H2O2 rather than releasing it. A vertical H2O2 gradient was observed that was lowest next to diatom-rich benthic algal mats. The diurnal changes in photosynthetic pigments included the violaxanthin and diadinoxanthin cycles; the former was induced prior to the latter, but neither was strictly correlated with NPQ. Conclusions The diurnal cycling of H2O2 was apparently modulated by the organisms in this freshwater algal community. Although the community showed flexibility in its levels of NPQ, the diurnal changes in

  2. Acetate biodegradation by anaerobic microorganisms at high pH and high calcium concentration

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Takahiro, E-mail: t-yoshida@rwmc.or.j [Central Research Institute of Electric Power Industry (CRIEPI), Nuclear Technology Research Laboratory, 2-11-1, Iwado-kita, Komae, Tokyo 201-8511 (Japan)

    2011-02-15

    Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic {sup 14}C compounds in cementitious repositories. Tamagawa river sediment or Teganuma pond sediment was anaerobically cultured with 5 mM acetate and 10 mM nitrate at pH 9.5-12 at 30 {sup o}C. After 20 and 90 days, the acetate concentration of the culture medium was analyzed and found to have decreased below 5 mM at pH {<=} 11. On the other hand, it did not decrease when either sediment was incubated in the absence of nitrate. These results suggest that nitrate-reducing bacteria can biodegrade acetate under more alkaline conditions than the reported pH range in which nitrate-reducing bacteria can exhibit activity. Acetate biodegradation was also examined at a high calcium concentration. Sediments were anaerobically cultured at pH 9.5 with 5 mM acetate and 10 mM nitrate in solution, equilibrated with ordinary Portland cement hydrate, in which the Ca concentration was 14.6 mM. No decrease in acetate concentration after incubation of the sediments was observed, nor was it lower than in the absence of cementitious composition, suggesting that kinetics of acetate biodegradation by anaerobic microorganisms is lowered by a high Ca concentration. - Research highlights: {yields} Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic {sup 14}C compounds in cementitious repositories. {yields} Nitrate-reducing bacteria can biodegrade acetate at pH {<=} 11. {yields} Kinetics of acetate biodegradation by anaerobic microorganisms might be lowered by a high Ca concentration.

  3. Hypothetical high-surface-area carbons with exceptional hydrogen storage capacities: open carbon frameworks.

    Science.gov (United States)

    Kuchta, Bogdan; Firlej, Lucyna; Mohammadhosseini, Ali; Boulet, Pascal; Beckner, Matthew; Romanos, Jimmy; Pfeifer, Peter

    2012-09-12

    A class of high-surface-area carbon hypothetical structures has been investigated that goes beyond the traditional model of parallel graphene sheets hosting layers of physisorbed hydrogen in slit-shaped pores of variable width. The investigation focuses on structures with locally planar units (unbounded or bounded fragments of graphene sheets), and variable ratios of in-plane to edge atoms. Adsorption of molecular hydrogen on these structures was studied by performing grand canonical Monte Carlo simulations with appropriately chosen adsorbent-adsorbate interaction potentials. The interaction models were tested by comparing simulated adsorption isotherms with experimental isotherms on a high-performance activated carbon with well-defined pore structure (approximately bimodal pore-size distribution), and remarkable agreement between computed and experimental isotherms was obtained, both for gravimetric excess adsorption and for gravimetric storage capacity. From this analysis and the simulations performed on the new structures, a rich spectrum of relationships between structural characteristics of carbons and ensuing hydrogen adsorption (structure-function relationships) emerges: (i) Storage capacities higher than in slit-shaped pores can be obtained by fragmentation/truncation of graphene sheets, which creates surface areas exceeding of 2600 m(2)/g, the maximum surface area for infinite graphene sheets, carried mainly by edge sites; we call the resulting structures open carbon frameworks (OCF). (ii) For OCFs with a ratio of in-plane to edge sites ≈1 and surface areas 3800-6500 m(2)/g, we found record maximum excess adsorption of 75-85 g of H(2)/kg of C at 77 K and record storage capacity of 100-260 g of H(2)/kg of C at 77 K and 100 bar. (iii) The adsorption in structures having large specific surface area built from small polycyclic aromatic hydrocarbons cannot be further increased because their energy of adsorption is low. (iv) Additional increase of hydrogen

  4. Initial Screening of Thermochemical Water-Splitting Cycles for High Efficiency Generation of Hydrogen Fuels Using Nuclear Power

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L.C.; Funk, J.F.; Showalter, S.K.

    1999-12-15

    OAK B188 Initial Screening of Thermochemical Water-Splitting Cycles for High Efficiency Generation of Hydrogen Fuels Using Nuclear Power There is currently no large scale, cost-effective, environmentally attractive hydrogen production process, nor is such a process available for commercialization. Hydrogen is a promising energy carrier, which potentially could replace the fossil fuels used in the transportation sector of our economy. Fossil fuels are polluting and carbon dioxide emissions from their combustion are thought to be responsible for global warming. The purpose of this work is to determine the potential for efficient, cost-effective, large-scale production of hydrogen utilizing high temperature heat from an advanced nuclear power station. Almost 800 literature references were located which pertain to thermochemical production of hydrogen from water and over 100 thermochemical watersplitting cycles were examined. Using defined criteria and quantifiable metrics, 25 cycles have been selected for more detailed study.

  5. High and rapid hydrogen release from thermolysis of ammonia borane near PEM fuel cell operating temperature

    Energy Technology Data Exchange (ETDEWEB)

    Varma, Arvind; Hwang, Hyun Tae; Al-Kukhun, Ahmad

    2016-11-15

    A system for generating and purifying hydrogen. To generate hydrogen, the system includes inlets configured to receive a hydrogen carrier and an inert insulator, a mixing chamber configured to combine the hydrogen carrier and the inert insulator, a heat exchanger configured to apply heat to the mixture of hydrogen carrier and the inert insulator, wherein the applied heat results in the generation of hydrogen from the hydrogen carrier, and an outlet configured to release the generated hydrogen. To purify hydrogen, the system includes a primary inlet to receive a starting material and an ammonia filtration subassembly, which may include an absorption column configured to absorb the ammonia into water for providing purified hydrogen at a first purity level. The ammonia filtration subassembly may also include an adsorbent member configured to adsorb ammonia from the starting material into an adsorbent for providing purified hydrogen at a second purity level.

  6. Perchlorate reduction by hydrogen autotrophic bacteria and microbial community analysis using high-throughput sequencing.

    Science.gov (United States)

    Wan, Dongjin; Liu, Yongde; Niu, Zhenhua; Xiao, Shuhu; Li, Daorong

    2016-02-01

    Hydrogen autotrophic reduction of perchlorate have advantages of high removal efficiency and harmless to drinking water. But so far the reported information about the microbial community structure was comparatively limited, changes in the biodiversity and the dominant bacteria during acclimation process required detailed study. In this study, perchlorate-reducing hydrogen autotrophic bacteria were acclimated by hydrogen aeration from activated sludge. For the first time, high-throughput sequencing was applied to analyze changes in biodiversity and the dominant bacteria during acclimation process. The Michaelis-Menten model described the perchlorate reduction kinetics well. Model parameters q(max) and K(s) were 2.521-3.245 (mg ClO4(-)/gVSS h) and 5.44-8.23 (mg/l), respectively. Microbial perchlorate reduction occurred across at pH range 5.0-11.0; removal was highest at pH 9.0. The enriched mixed bacteria could use perchlorate, nitrate and sulfate as electron accepter, and the sequence of preference was: NO3(-) > ClO4(-) > SO4(2-). Compared to the feed culture, biodiversity decreased greatly during acclimation process, the microbial community structure gradually stabilized after 9 acclimation cycles. The Thauera genus related to Rhodocyclales was the dominated perchlorate reducing bacteria (PRB) in the mixed culture.

  7. Zeolite-templated carbon materials for high-pressure hydrogen storage.

    Science.gov (United States)

    Stadie, Nicholas P; Vajo, John J; Cumberland, Robert W; Wilson, Andrew A; Ahn, Channing C; Fultz, Brent

    2012-07-03

    Zeolite-templated carbon (ZTC) materials were synthesized, characterized, and evaluated as potential hydrogen storage materials between 77 and 298 K up to 30 MPa. Successful synthesis of high template fidelity ZTCs was confirmed by X-ray diffraction and nitrogen adsorption at 77 K; BET surface areas up to ~3600 m(2) g(-1) were achieved. Equilibrium hydrogen adsorption capacity in ZTCs is higher than all other materials studied, including superactivated carbon MSC-30. The ZTCs showed a maximum in Gibbs surface excess uptake of 28.6 mmol g(-1) (5.5 wt %) at 77 K, with hydrogen uptake capacity at 300 K linearly proportional to BET surface area: 2.3 mmol g(-1) (0.46 wt %) uptake per 1000 m(2) g(-1) at 30 MPa. This is the same trend as for other carbonaceous materials, implying that the nature of high-pressure adsorption in ZTCs is not unique despite their narrow microporosity and significantly lower skeletal densities. Isoexcess enthalpies of adsorption are calculated between 77 and 298 K and found to be 6.5-6.6 kJ mol(-1) in the Henry's law limit.

  8. Self-assembly of thiophene derivatives on highly oriented pyrolytic graphite: hydrogen bond effect.

    Science.gov (United States)

    Xu, Li-Ping; Liu, Yibiao; Zhao, Jing; Wang, Shuqi; Lin, Chen-Sheng; Zhang, Rui-Qin; Wen, Yongqiang; Du, Hongwu; Zhang, Xueji

    2013-02-01

    In this paper, to elucidate the hydrogen bond effect on the assembly behavior, we studied the assembly structures of two carboxylic substituted thiophene derivatives on highly oriented pyrolytic graphite (HOPG) by scanning tunneling microscopy. Here thiophene-2-carboxylic acid (TCA) and thiophene-2,5-dicarboxylic acid (TDA) were employed. TDA molecules spontaneously adsorb on the HOPG surface and self-organize into a two-dimensional (2D) assembly with well-defined structure. Two types of domain could be observed. Each TDA molecule appears as a round circle with two small faint dots and forms hydrogen bonds with neighbours. Besides monolayer structure, a bilayer structure of TDA adlayer on HOPG was also observed in this research. Remnant TDA molecules adsorb on the monolayer of TDA and bilayer structure is formed. In contrast to TDA, no ordered structure of TCA on HOPG can be observed. TCA molecules have high propensity to form dimers through H-bond between carboxylic groups. But TCA dimer is not stable enough for either adsorption or imaging. Our result provides a new example for understanding hydrogen effect on stabilizing and controlling two-dimensional assembly structure and is helpful for surface nanofabrication and development of electric nanodevices.

  9. Investigation of cryogenic hydrogen storage on high surface area activated carbon. Equilibrium and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Paggiaro, Ricardo Gaspar

    2008-11-29

    This thesis investigates cryo-adsorptive systems for hydrogen storage for mobile applications. By means of macroscopic and microscopic balance models, an extensive analysis is carried out, including among others the investigation of the thermal effects during high-pressure system filling, venting losses during normal operation and inactivity, time-course of system pressure and temperature and gas delivery under various operating conditions. Model results were compared with experimental data, good agreement was obtained. The analysis also includes a comparison to other storage technologies such as cryo-compressed gas and liquefaction storage. The results show that cryo-adsorptive systems have storage characteristics comparable to compressed gas systems, but at a much lower pressure. They are also energetically more efficient than liquid hydrogen systems. However, the necessity of cryotemperatures and thermal management during operation and filling might limit their application. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Ciccarelli, G.; Ginsburg, T.; Boccio, J.; Economos, C.; Finfrock, C.; Gerlach, L. [Brookhaven National Lab., Upton, NY (United States); Sato, K.; Kinoshita, M. [Nuclear Power Engineering Corp., Tokyo (Japan)

    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.

  11. High speed diagnostics for characterization of oxygen / hydrogen rocket injector flowfields

    Science.gov (United States)

    Locke, Justin M.

    location. The time-averaged results are consistent with previous spatially-resolved Raman spectroscopy measurements made in a similar rocket combustor under similar flow conditions. The primary atomization and combustion characteristics of a liquid oxygen (LOX) / gaseous hydrogen (GH2) shear coaxial injector element were also experimentally investigated. High speed movies using a shadowgraph imaging technique to visualize the LOX core were recorded for both hot-fire (LOX/GH 2) and cold-flow (LOX/gaseous oxygen (GO2)) conditions with the same injector and chamber. Flow conditions were set to approximate realistic rocket conditions. For the hot-fire tests (LOX/GH2), chamber pressures were 600, 730, and 920 psia, with momentum flux ratios (annulus flow/post flow) of 2.7, 2.0 and 1.6 respectively. The rocket assembly utilized a preburner to provide a background flow (M≈0.1) of hot gaseous nitrogen (GN2 )/GH2/water (H2O) gas with 25% volumetric concentration of hydrogen. For the cold-flow tests (LOX/GO2 with GO2 background flow), chamber pressures were 650 and 830 psia, thus above and below the critical pressure of oxygen (731.6 psia), with momentum flux ratios (annulus flow/post flow) of 2.2 and 1.8 respectively. The high speed visualizations under hot-fire conditions show a long sinuous LOX core region that breaks into large dense-oxygen structures, which are then quickly consumed. These results do not agree with the classical phenomenological breakup model that suggests a liquid core that is rapidly sheared into a drop cloud. Rather, a large-scale fragmentation model may be better suited to describe the primary atomization behavior in combusting flow from a LOX/GH2 shear coaxial injector element at realistic rocket conditions. Unlike the hot-fire case, cold-flow LOX visualization movies show a clear difference between the two chamber pressures, with the higher pressure (supercritical) case resembling behavior indicative of gaseous mixing compared to the typically two phase

  12. Enhanced energy conversion efficiency from high strength synthetic organic wastewater by sequential dark fermentative hydrogen production and algal lipid accumulation.

    Science.gov (United States)

    Ren, Hong-Yu; Liu, Bing-Feng; Kong, Fanying; Zhao, Lei; Xing, Defeng; Ren, Nan-Qi

    2014-04-01

    A two-stage process of sequential dark fermentative hydrogen production and microalgal cultivation was applied to enhance the energy conversion efficiency from high strength synthetic organic wastewater. Ethanol fermentation bacterium Ethanoligenens harbinense B49 was used as hydrogen producer, and the energy conversion efficiency and chemical oxygen demand (COD) removal efficiency reached 18.6% and 28.3% in dark fermentation. Acetate was the main soluble product in dark fermentative effluent, which was further utilized by microalga Scenedesmus sp. R-16. The final algal biomass concentration reached 1.98gL(-1), and the algal biomass was rich in lipid (40.9%) and low in protein (23.3%) and carbohydrate (11.9%). Compared with single dark fermentation stage, the energy conversion efficiency and COD removal efficiency of two-stage system remarkably increased 101% and 131%, respectively. This research provides a new approach for efficient energy production and wastewater treatment using a two-stage process combining dark fermentation and algal cultivation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Chaetomium thermophilum formate dehydrogenase has high activity in the reduction of hydrogen carbonate (HCO3 -) to formate.

    Science.gov (United States)

    Aslan, Aşkın Sevinç; Valjakka, Jarkko; Ruupunen, Jouni; Yildirim, Deniz; Turner, Nicholas J; Turunen, Ossi; Binay, Barış

    2017-01-01

    While formate dehydrogenases (FDHs) have been used for cofactor recycling in chemoenzymatic synthesis, the ability of FDH to reduce CO2 could also be utilized in the conversion of CO2 to useful products via formate (HCOO-). In this study, we investigated the reduction of CO2 in the form of hydrogen carbonate (HCO3-) to formate by FDHs from Candida methylica (CmFDH) and Chaetomium thermophilum (CtFDH) in a NADH-dependent reaction. The catalytic performance with HCO3- as a substrate was evaluated by measuring the kinetic rates and conducting productivity assays. CtFDH showed a higher efficiency in converting HCO3- to formate than CmFDH, whereas CmFDH was better in the oxidation of formate. The pH optimum of the reduction was at pH 7-8. However, the high concentrations of HCO3- reduced the reaction rate. CtFDH was modeled in the presence of HCO3- showing that it fits to the active site. The active site setting for hydride transfer in CO2 reduction was modeled. The hydride donated by NADH would form a favorable contact to the carbon atom of HCO3-, resulting in a surplus of electrons within the molecule. This would cause the complex formed by hydrogen carbonate and the hydride to break into formate and hydroxide ions. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Development of Criteria for Flameholding Tendencies within Premixer Passages for High Hydrogen Content Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Elliot Sullivan- [Univ. of California, Irvine, CA (United States); McDonell, Vincent G. [Univ. of California, Irvine, CA (United States)

    2014-12-01

    Due to increasingly stringent air quality requirements stationary power gas turbines have moved to lean-premixed operation, which reduces pollutant emissions but can result in flashback. Flashback can cause serious damage to the premixer hardware. Curtailing flashback can be difficult with hydrocarbon fuels and becomes even more challenging when hydrogen is used as the fuel. The two main approaches for coping with flashback are either to design a combustor that is resistant to flashback, or to design a premixer that will not anchor a flame if flashback occurs. Even with a well-designed combustor flashback can occur under certain circumstances, thus it is necessary to determine how to avoid flameholding within the premixer passageways of a gas turbine. To this end, an experiment was designed that would determine the flameholding propensities at elevated pressures and temperatures of three different classes of geometric features commonly found in gas turbine premixers, with both natural gas and hydrogen fuel. Experiments to find the equivalence ratio at blow off were conducted within an optically accessible test apparatus with four flameholders: 0.25 and 0.50 inch diameter cylinders, a reverse facing step with a height of 0.25 inches, and a symmetric airfoil with a thickness of 0.25 inches and a chord length of one inch. Tests were carried out at temperatures between 300 K and 750 K, at pressures up to 9 atmospheres. Typical bulk velocities were between 40 and 100 m/s. The effect of airfoil’s angle of rotation was also investigated. Blow off for hydrogen flames was found to occur at much lower adiabatic flame temperatures than natural gas flames. Additionally it was observed that at high pressures and high turbulence intensities, reactant velocity does not have a noticeable effect on the point of blow off due in large part to corresponding increases in turbulent flame speed. Finally a semi empirical correlation was developed that predicts flame extinction for both

  15. Hydrogen adsorption and diffusion, and subcritical-crack growth in high strength steels and nickel base alloys

    Science.gov (United States)

    Wei, R. P.; Klier, K.; Simmons, G. W.; Chornet, E.

    1973-01-01

    Embrittlement, or the enhancement of crack growth by gaseous hydrogen in high strength alloys, is of primary interest in selecting alloys for various components in the space shuttle. Embrittlement is known to occur at hydrogen gas pressures ranging from fractions to several hundred atmospheres, and is most severe in the case of martensitic high strength steels. Kinetic information on subcritical crack growth in gaseous hydrogen is sparse at this time. Corroborative information on hydrogen adsorption and diffusion is inadequate to permit a clear determination of the rate controlling process and possible mechanism in hydrogen enhanced crack growth, and for estimating behavior over a range of temperatures and pressures. Therefore, coordinated studies of the kinetics of crack growth, and adsorption and diffusion of hydrogen, using identical materials, have been initiated. Comparable conditions of temperature and pressure will be used in the chemical and mechanical experiments. Inconel 718 alloy and 18Ni(200) maraging steel have been selected for these studies. Results from these studies are expected to provide not only a better understanding of the gaseous hydrogen embrittlement phenomenon itself, but also fundamental information on hydrogen adsorption and diffusion, and crack growth information that can be used directly for design.

  16. Carbon Nanofibers Modified Graphite Felt for High Performance Anode in High Substrate Concentration Microbial Fuel Cells

    Science.gov (United States)

    Shen, Youliang; Zhou, Yan; Chen, Shuiliang; Yang, Fangfang; Zheng, Suqi; Hou, Haoqing

    2014-01-01

    Carbon nanofibers modified graphite fibers (CNFs/GF) composite electrode was prepared for anode in high substrate concentration microbial fuel cells. Electrochemical tests showed that the CNFs/GF anode generated a peak current density of 2.42 mA cm−2 at a low acetate concentration of 20 mM, which was 54% higher than that from bare GF. Increase of the acetate concentration to 80 mM, in which the peak current density of the CNFs/GF anode greatly increased and was up to 3.57 mA cm−2, was seven times as that of GF anode. Morphology characterization revealed that the biofilms in the CNFs/GF anode were much denser than those in the bare GF. This result revealed that the nanostructure in the anode not only enhanced current generation but also could tolerate high substrate concentration. PMID:24883348

  17. Carbon nanofibers modified graphite felt for high performance anode in high substrate concentration microbial fuel cells.

    Science.gov (United States)

    Shen, Youliang; Zhou, Yan; Chen, Shuiliang; Yang, Fangfang; Zheng, Suqi; Hou, Haoqing

    2014-01-01

    Carbon nanofibers modified graphite fibers (CNFs/GF) composite electrode was prepared for anode in high substrate concentration microbial fuel cells. Electrochemical tests showed that the CNFs/GF anode generated a peak current density of 2.42 mA cm(-2) at a low acetate concentration of 20 mM, which was 54% higher than that from bare GF. Increase of the acetate concentration to 80 mM, in which the peak current density of the CNFs/GF anode greatly increased and was up to 3.57 mA cm(-2), was seven times as that of GF anode. Morphology characterization revealed that the biofilms in the CNFs/GF anode were much denser than those in the bare GF. This result revealed that the nanostructure in the anode not only enhanced current generation but also could tolerate high substrate concentration.

  18. Time and concentration dependency in the potentially affected fraction of species: the case of hydrogen peroxide treatment of ballast water

    NARCIS (Netherlands)

    Smit, M.G.D.; Ebbens, E.; Jak, R.G.; Huijbregts, M.J.A.

    2008-01-01

    Transport of large volumes of ballast water contributes greatly to invasions of species. Hydrogen peroxide (H2O2) can be used as a disinfectant to prevent the spread of exotic species via ballast water. Instead of using environmental risk assessment techniques for protecting a certain fraction of

  19. Selection of common bean lines with high grain yield and high grain calcium and iron concentrations

    Directory of Open Access Journals (Sweden)

    Nerinéia Dalfollo Ribeiro

    2014-02-01

    Full Text Available Genetic improvement of common bean nutritional quality has advantages in marketing and can contribute to society as a food source. The objective of this study was to evaluate the genetic variability for grain yield, calcium and iron concentrations in grains of inbred common bean lines obtained by different breeding methods. For this, 136 F7 inbred lines were obtained using the Pedigree method and 136 F7 inbred lines were obtained using the Single-Seed Descent (SSD method. The lines showed genetic variability for grain yield, and concentrations of calcium and iron independently of the method of advancing segregating populations. The Pedigree method allows obtaining a greater number of lines with high grain yield. Selection using the SSD method allows the identification of a larger number of lines with high concentrations of calcium and iron in grains. Weak negative correlations were found between grain yield and calcium concentration (r = -0.0994 and grain yield and iron concentration (r = -0.3926. Several lines show genetic superiority for grain yield and concentrations of calcium and iron in grains and their selection can result in new common bean cultivars with high nutritional quality.

  20. Effects of temperature, salt concentration, and the protonation state on the dynamics and hydrogen-bond interactions of polyelectrolyte multilayers on lipid membranes.

    Science.gov (United States)

    Lee, Hwankyu

    2016-03-07

    Polyelectrolyte multilayers, which consist of poly-l-lysines (PLL) and hyaluronic acids (HA), are simulated on phospholipid membranes with explicit water at different temperatures, salt concentrations, and protonation states of PLL that correspond to pH 7 or higher. PLL and HA polymers, which are initially sequentially deposited as three HA/PLL bilayers above the membrane, partially intermix with each other within 300 ns, and with a significant amount of water at almost half of its bulk density. With reduced protonation of amine groups of PLL, the polymers diffuse faster, especially at higher temperatures, and for 0%-protonation, disperse into the water, due to the many fewer hydrogen bonds between PLL and HA polymers. When PLL is protonated, the addition of salt ions weakens electrostatic interactions between PLL and HA and, at 0.5 M NaCl, eventually reduces the number of hydrogen bonds, which in experiments leads to hole formation inside the PLL/HA film. Multilayers are stabilized by hydrogen bonds, primarily between charged groups and to a lesser extent between uncharged groups. PLL and HA also electrostatically interact with lipid head groups of membranes which reduces the lateral mobility of membrane lipids, to an extent dependent on the salt concentration. These findings help quantitate the effects of temperature, salt, and the protonation state (or pH) on the stability and dynamics of multilayers and membranes, and show trends that compare favorably with the experimental observations of the swelling of multilayers.

  1. Hydrogenation induced deviation of temperature and concentration dependences of polymer-solvent interactions in poly(vinyl chloride) and a new eco-friendly plasticizer

    Science.gov (United States)

    Liu, Yang; Zhang, Rongchun; Wang, Xiaoliang; Sun, Pingchuan; Chen, Wei; Shen, Jianyi; Xue, Gi

    2015-06-01

    As a substitute for di-2-ethylhexyl phthalate (DOP), a new eco-friendly plasticizer, di(2-ethylhexyl) cyclohexane-1,2-dicarboxylate (DEHHP), was systematically studied in this work, mainly focusing on its interaction with poly(vinyl chloride) (PVC). The temperature and concentration dependences of polymer-solvent interactions in PVC/DEHHP were systematically investigated by rheology, low-field NMR and molecular dynamics simulations, and the results were quite different from those in PVC/DOP. With temperature increasing or PVC concentration decreasing, rheology experiments revealed that polymer-solvent interactions in PVC/DEHHP were weaker than that in PVC/DOP. Low-field 1H NMR results showed that the number of polymer-solvent complexes decreased as temperature increased. A faster decreasing rate of this number made the polymer-solvent interactions weaker in PVC/DEHHP than in PVC/DOP. Molecular dynamics simulations were further performed to study the role of polymer-solvent hydrogen bonding interactions in the systems. The radial distribution function showed that heating and dilution both resulted in faster molecular motions, and disassociation of the hydrogen bonds in the simplex hydrogen bonding system. Therefore, heating and dilution had an equivalent effect on the polymer-solvent interactions.

  2. Raman spectroscopic determination of the molecular constants of the hydrogen isotopologues with high accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Krasch, Bennet; Mirz, Sebastian; Groessle, Robin [Karlsruhe Institute of Technology KIT (Germany). Institute for Technical Physics (ITEP), Tritium Laboratory Karlsruhe (TLK); Collaboration: KATRIN-Collaboration

    2016-07-01

    The interest in the thermodynamic properties of gases as the chemical equilibrium is faced by the challenge of time-consuming and technical extensive experimental setups. One possible solution is the derivation of these properties from the molecular constants. The rotational and vibrational movement of diatomic molecules, as the hydrogen isotopologues, is described by the concept of the rotational anharmonic oscillator. The molecular constants are the free parameters of this concept. Molecular constants themselves can be determined by measuring the line position of rotational and/or rotational transitions e.g. with Raman spectroscopy for hydrogen as it has been done since several years. In this contribution a Raman method was development to measure the molecular constant of the hydrogen isotopologues with high accuracy to obtain reliable results. But not only the method was development but also a complete measurement uncertainty budget was set up. The uncertainty budget contains all possible sources for uncertainties from the measurement period or the analysis process as well the contribution of each single uncertainty. The method and the uncertainty budget were exemplary tested on Deuterium.

  3. Design of hydroforming processes for metallic liners used in high pressure hydrogen storage

    Science.gov (United States)

    Gelin, J. C.; Labergere, C.; Thibaud, S.; Boudeau, N.

    2005-08-01

    Within the framework of an European project concerning hydrogen storage, one analyze the way to manufacture high pressure tanks (700bars) for hydrogen storage, intended to be embarked for using in motor vehicles. These tanks consist of a metallic liner, which ensure a barrier role compared to the hydrogen atoms as well as a part of the mechanical resistance, and of a composite envelope built by filament rolling up which ensures the complementary part of the mechanical resistance. The paper describes the work completed within this framework, on the basis of the simulation of the hydroforming process thanks to the complete control of the process, in volume of fluid injected. One was thus brought to develop an optimization module based on finite element calculations. This optimization module includes MPI library in order to launch several calculations in parallel on a Linux cluster. It consists in seeking the optimal evolution of the fluid volume injected vs. time to obtain a good quality component. In our case, the optimization criterion is based on the variation thickness of the tube and the possible appearance of necking. It is shown that such a way for controlling the process provide the way to get minimal thickness variation, comparatively to standard optimization approaches where the process parameters are discretized through processing time in a more standard way.

  4. Highly Efficient Carbon Dioxide Hydrogenation to Methanol Catalyzed by Zigzag Platinum-Cobalt Nanowires.

    Science.gov (United States)

    Bai, Shuxing; Shao, Qi; Feng, Yonggang; Bu, Lingzheng; Huang, Xiaoqing

    2017-06-01

    Carbon dioxide (CO2 ) hydrogenation is an effective strategy for CO2 utilization, while unsatisfied conversion efficiencies remain great challenges. It is reported herein that zigzag Pt-Co nanowires (NWs) with Pt-rich surfaces and abundant steps/edges can perform as highly active and stable CO2 hydrogenation catalysts. It is found that tuning the Pt/Co ratio of the Pt-Co NWs, solvents, and catalyst supports could well optimize the CO2 hydrogenation to methanol (CH3 OH) with the Pt4 Co NWs/C exhibiting the best performance, outperforming all the previous catalysts. They are also very durable with limited activity decays after six catalytic cycles. The diffuse reflectance infrared Fourier transform spectroscopy result of CO2 adsorption shows that the Pt4 Co NWs/C undergoes the adsorption/activation of CO2 by forming appropriate carboxylate intermediates, and thus enhancing the CH3 OH production. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Experimental and First-Principles Investigation of MoWS2 with High Hydrogen Evolution Performance.

    Science.gov (United States)

    Li, Honglin; Yu, Ke; Tang, Zheng; Zhu, Ziqiang

    2016-11-02

    Electrochemically splitting water for hydrogen evolution has attracted a lot attention and developed into a promising approach to produce hydrogen energy. Searching for high-activity and economical electrocatalysts to replace Pt-based catalysts remains a great challenge. In this paper, we reported a concise and effective strategy to fabricate the novel MoWS2 composite for use as the electrocatalyst through a hydrothermal method for the first time. The final obtained MoWS2 composite demonstrated a well-defined hierarchical structure and established that its densely stacked nanopetals act as the active sites in the corresponding hydrogen evolution reaction (HER) processes. Experimental results show that the composites can deliver a clearly promoted HER activity and are superior to the pure structure. In order to give a more in-depth explanation, we also performed a first-principles calculation to further survey the electronic properties, compound form, and HER mechanism of different structures. The charge distribution of MoWS2 composite indicates that electrons can directionally transfer from WS2 to the neighboring MoS2 and form an "electron-rich" configuration, which is beneficial to increase the HER rate and promote the overall performance. This thorough research will not only provide new thought to the analyses and elucidation of the inner mechanism of the HER process for this kind of two-dimensional composite but also guide further work on the basis of experimental and calculation results.

  6. High volume hydrogen production from the hydrolysis of sodium borohydride using a cobalt catalyst supported on a honeycomb matrix

    Science.gov (United States)

    Marchionni, Andrea; Bevilacqua, Manuela; Filippi, Jonathan; Folliero, Maria G.; Innocenti, Massimo; Lavacchi, Alessandro; Miller, Hamish A.; Pagliaro, Maria V.; Vizza, Francesco

    2015-12-01

    Hydrogen storage and distribution will be two very important aspects of any renewable energy infrastructure that uses hydrogen as energy vector. The chemical storage of hydrogen in compounds like sodium borohydride (NaBH4) could play an important role in overcoming current difficulties associated with these aspects. Sodium borohydride is a very attractive material due to its high hydrogen content. In this paper, we describe a reactor where a stable cobalt based catalyst supported on a commercial Cordierite Honeycomb Monolith (CHM) is employed for the hydrolysis of alkaline stabilized NaBH4 (SBH) aqueous solutions. The apparatus is able to operate at up to 5 bar and 130 °C, providing a hydrogen generation rate of up to 32 L min-1.

  7. An Automatic High Efficient Method for Dish Concentrator Alignment

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2014-01-01

    for the alignment of faceted solar dish concentrator. The isosceles triangle configuration of facet’s footholds determines a fixed relation between light spot displacements and foothold movements, which allows an automatic determination of the amount of adjustments. Tests on a 25 kW Stirling Energy System dish concentrator verify the feasibility, accuracy, and efficiency of our method.

  8. Porous boron nitride with a high surface area: hydrogen storage and water treatment.

    Science.gov (United States)

    Li, Jie; Lin, Jing; Xu, Xuewen; Zhang, Xinghua; Xue, Yanming; Mi, Jiao; Mo, Zhaojun; Fan, Ying; Hu, Long; Yang, Xiaojing; Zhang, Jun; Meng, Fanbin; Yuan, Songdong; Tang, Chengchun

    2013-04-19

    We report on the synthesis of high-quality microporous/mesoporous BN material via a facile two-step approach. An extremely high surface area of 1687 m(2) g(-1) and a large pore volume of 0.99 cm(3) g(-1) have been observed in the synthesized BN porous whiskers. The formation of the porous structure was attributed to the group elimination of organic species in a BN precursor, melamine diborate molecular crystal. This elimination method maintained the ordered pore structure and numerous structural defects. The features including high surface area, pore volume and structural defects make the BN whiskers highly suitable for hydrogen storage and wastewater treatment applications. We demonstrate excellent hydrogen uptake capacity of the BN whiskers with high weight adsorption up to 5.6% at room temperature and at the relatively low pressure of 3 MPa. Furthermore, the BN whiskers also exhibit excellent adsorption capacity of methyl orange and copper ions, with the maximum removal capacity of 298.3 and 373 mg g(-1) at 298 K, respectively.

  9. Catalytic processing of high-sulfur fuels for distributed hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Muradov, Nazim; Ramasamy, Karthik; Huang, Cunping; T-Raissi, Ali [Central Florida Univ., FL (United States)

    2010-07-01

    In this work, the development of a new on-demand hydrogen production technology is reported. In this process, a liquid hydrocarbon fuel (e.g., high-S diesel) is first catalytically pre-reformed to shorter chain gaseous hydrocarbons (predominantly, C{sub 1}-C{sub 3}) before being directed to the steam reformer, where it is converted to syngas and then to high-purity hydrogen. In the pre-reformer, most sulfurous species present in the fuel are catalytically converted to H{sub 2}S. In the desulfurization unit, H{sub 2}S is scrubbed and converted to H{sub 2} and elemental sulfur. Desulfurization of the pre-reformate gas is carried out in a special regenerative redox system, which includes Fe(II)/Fe(III)-containing aqueous phase scrubber coupled with an electrolyzer. The integrated pre-reformer/scrubber/electrolyzer unit operated successfully on high-S diesel fuel for more than 100 hours meeting the required desulfurization target of >95 % sulfur removal. (orig.)

  10. Intercomparison of passive microwave sea ice concentration retrievals over the high-concentration Arctic sea ice

    DEFF Research Database (Denmark)

    andersen, susanne; Tonboe, R.; Kaleschke, L.

    2007-01-01

    [1] Measurements of sea ice concentration from the Special Sensor Microwave Imager (SSM/I) using seven different algorithms are compared to ship observations, sea ice divergence estimates from the Radarsat Geophysical Processor System, and ice and water surface type classification of 59 wide...... a trusted subset of the SAR scenes across the central Arctic allow the separation of the ice concentration uncertainty due to emissivity variations and sensor noise from other error sources during the winter of 2003-2004. Depending on the algorithm, error standard deviations from 2.5 to 5.0% are found...... with sensor noise between 1.3 and 1.8%. This is in accord with variability estimated from analysis of SSM/I time series. Algorithms, which primarily use 85 GHz information, consistently give the best agreement with both SAR ice concentrations and ship observations. Although the 85 GHz information is more...

  11. Design philosophy and construction of a high concentration compound parabolic concentrator

    CSIR Research Space (South Africa)

    Roos, TH

    2010-09-01

    Full Text Available stream_source_info Roos_2010.pdf.txt stream_content_type text/plain stream_size 19653 Content-Encoding UTF-8 stream_name Roos_2010.pdf.txt Content-Type text/plain; charset=UTF-8 THE DESIGN PHILOSOPHY AND CONSTRUCTION... and actual efficiency will be determined using a hemispherical cavity calorimeter. Keywords: CPC, compound parabolic concentrator, sandwich 1. Introduction A 25m2 target-aligned research heliostat has been developed at CSIR [1] to provide the concentrated...

  12. Starch source in high concentrate rations does not affect rumen pH, histamine and lipopolysaccharide concentrations in dairy cows

    NARCIS (Netherlands)

    Pilachai, R.; Schonewille, J.T.; Thamrongyoswittayakul, C.; Aiumlamai, S.; Wachirapakom, C.; Everts, H.; Hendriks, W.H.

    2012-01-01

    The replacement of ground corn by cassava meal on rumen pH, lipopolysaccharide (LPS) and histamine concentrations under typical Thai feeding conditions (high concentrate diets and rice straw as the sole source of roughage) was investigated. Four rumen-fistulated crossbred Holstein, non-pregnant, dry

  13. Selective oxidation of glycerol to formic acid in highly concentrated aqueous solutions with molecular oxygen using V-substituted phosphomolybdic acids

    KAUST Repository

    Zhang, Jizhe

    2014-01-01

    Formic acid is an important commodity chemical as well as a promising medium for hydrogen storage and hydrogen production. In this paper, we report that formic acid can be produced through selective oxidation of glycerol, a low-cost by-product of biodiesel, by using vanadium-substituted phosphomolybdic acids as catalysts and molecular oxygen as the oxidant. Significantly, this catalytic system allows for high-concentration conversions and thus leads to exceptional efficiency. Specifically, 3.64 g of formic acid was produced from 10 g of glycerol/water (50/50 in weight) solution. © 2014 the Partner Organisations.

  14. Well-defined and high resolution Pt nanowire arrays for a high performance hydrogen sensor by a surface scattering phenomenon.

    Science.gov (United States)

    Yoo, Hae-Wook; Cho, Soo-Yeon; Jeon, Hwan-Jin; Jung, Hee-Tae

    2015-02-03

    Developing hydrogen (H2) sensors with a high sensitivity, rapid response, long-term stability, and high throughput is one of the critical issues in energy and environmental technology [Hübert et al. Sens. Actuators, B 2011, 157, 329]. To date, H2 sensors have been mainly developed using palladium (Pd) as the channel material because of its high selectivity and strong affinity to the H2 molecule [(Xu et al. Appl. Phys. Lett. 2005, 86, 203104), (Offermans et al. Appl. Phys. Lett. 2009, 94, 223110), (Yang et al. Nano Lett. 2009, 9, 2177), (Yang et al. ACS Nano 2010, 4, 5233), and (Zou et al. Chem. Commun. 2012, 48, 1033)]. Despite significant progress in this area, Pd based H2 sensors suffer from fractures on their structure due to hydrogen adsorption induced volumetric swelling during the α → β phase transition, leading to poor long-term stability and reliability [(Favier et al. Science 2001, 293, 2227), (Walter et al. Microelectron. Eng. 2002, 61–62, 555), and (Walter et al. Anal. Chem. 2002, 74, 1546)]. In this study, we developed a platinum (Pt) nanostructure based H2 sensor that avoids the stability limitations of Pd based sensors. This sensor exhibited an excellent sensing performance, low limit of detection (LOD, 1 ppm), reproducibility, and good recovery behavior at room temperature. This Pt based H2 sensor relies on a highly periodic, small cross sectional dimension (10–40 nm) and a well-defined configuration of Pt nanowire arrays over a large area. The resistance of the Pt nanowire arrays significantly decreased upon exposure to H2 due to reduced electron scattering in the cross section of the hydrogen adsorbed Pt nanowires, as compared to the oxygen terminated original state. Therefore, these well-defined Pt nanowire arrays prepared using advanced lithographic techniques can facilitate the production of high performance H2 sensors.

  15. Hydrogen Embrittlement

    Science.gov (United States)

    Woods, Stephen; Lee, Jonathan A.

    2016-01-01

    hydrogen embrittlement. The effects of hydrogen gas on mechanical properties such as tensile strength, ductility, fracture, low and high cycle fatigue, crack growth rate, and creep rupture are analyzed with respect to the general trends established from the HEE index values. It is observed that the severity of HE effects is also influenced by environmental factors such as pressure, temperature, and hydrogen gas purity. The severity of HE effects is also influenced by material factors such as surface finish, heat treatment, and product forms, compositions, grain direction, and crystal orientations.

  16. High-Efficiency Organic Solar Concentrators for Photovoltaics

    National Research Council Canada - National Science Library

    Michael J. Currie; Jonathan K. Mapel; Timothy D. Heidel; Shalom Goffri; Marc A. Baldo

    2008-01-01

    The cost of photovoltaic power can be reduced with organic solar concentrators. These are planar waveguides with a thin-film organic coating on the face and inorganic solar cells attached to the edges...

  17. Ozone concentration characteristics at a high-elevation forest site

    Science.gov (United States)

    G. Wooldridge; K. Zeller; R. Musselman

    1997-01-01

    Atmospheric ozone concentrations have been monitored at a subalpine forest ecosystem site, 3180m above mean sea level (msl), and at a 2680m msl forest-steppe ecotone site 15km to the southeast. Ozone concentrations were monitored at three heights above the ground on a 30m tower at the higher elevation site, and on a 10m tower in a large meadow downwind of this site....

  18. Two-dimensional gold nanostructures with high activity for selective oxidation of carbon–hydrogen bonds

    KAUST Repository

    Wang, Liang

    2015-04-22

    Efficient synthesis of stable two-dimensional (2D) noble metal catalysts is a challenging topic. Here we report the facile synthesis of 2D gold nanosheets via a wet chemistry method, by using layered double hydroxide as the template. Detailed characterization with electron microscopy and X-ray photoelectron spectroscopy demonstrates that the nanosheets are negatively charged and [001] oriented with thicknesses varying from single to a few atomic layers. X-ray absorption spectroscopy reveals unusually low gold–gold coordination numbers. These gold nanosheets exhibit high catalytic activity and stability in the solvent-free selective oxidation of carbon–hydrogen bonds with molecular oxygen.

  19. Mechanical ball-milling preparation of fullerene/cobalt core/shell nanocomposites with high electrochemical hydrogen storage ability.

    Science.gov (United States)

    Bao, Di; Gao, Peng; Shen, Xiande; Chang, Cheng; Wang, Longqiang; Wang, Ying; Chen, Yujin; Zhou, Xiaoming; Sun, Shuchao; Li, Guobao; Yang, Piaoping

    2014-02-26

    The design and synthesis of new hydrogen storage nanomaterials with high capacity at low cost is extremely desirable but remains challenging for today's development of hydrogen economy. Because of the special honeycomb structures and excellent physical and chemical characters, fullerenes have been extensively considered as ideal materials for hydrogen storage materials. To take the most advantage of its distinctive symmetrical carbon cage structure, we have uniformly coated C60's surface with metal cobalt in nanoscale to form a core/shell structure through a simple ball-milling process in this work. The X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectra, high-solution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrometry (EDX) elemental mappings, and X-ray photoelectron spectroscopy (XPS) measurements have been conducted to evaluate the size and the composition of the composites. In addition, the blue shift of C60 pentagonal pinch mode demonstrates the formation of Co-C chemical bond, and which enhances the stability of the as-obtained nanocomposites. And their electrochemical experimental results demonstrate that the as-obtained C60/Co composites have excellent electrochemical hydrogen storage cycle reversibility and considerably high hydrogen storage capacities of 907 mAh/g (3.32 wt % hydrogen) under room temperature and ambient pressure, which is very close to the theoretical hydrogen storage capacities of individual metal Co (3.33 wt % hydrogen). Furthermore, their hydrogen storage processes and the mechanism have also been investigated, in which the quasi-reversible C60/Co↔C60/Co-Hx reaction is the dominant cycle process.

  20. Construction and test of a high power injector of hydrogen cluster ions

    CERN Document Server

    Becker, E W; Hagena, O F; Henkes, P R W; Klingelhofer, R; Moser, H O; Obert, W; Poth, I

    1979-01-01

    A high power injector of hydrogen cluster ions, rated for 1 MV and 100 kW, is described. The injector is split in three separate tanks connected by a 1 MV transfer line. The cluster ion beam source and all its auxiliary equipment is placed at high voltage, insulated by SF/sub 6/ gas at pressure of 4 bar. The main components of the injector are: The cluster ion beam source with integrated helium cryopumps, the CERN type acceleration tube with 750 mm ID, the beam dump designed to handle the mass and energy flux under DC conditions, a 1 MV high voltage terminal for the auxiliary equipment supplied by its 40 kVA power supply with power, and the 1 MV 120 kW DC high voltage generator. This injector is installed in Karlsruhe. Performance tests were carried out successfully. It is intended to use this injector for refuelling experiments at the ASDEX Tokamak. (12 refs).

  1. Magnesium for Hydrogen Storage

    DEFF Research Database (Denmark)

    Pedersen, Allan Schrøder; Kjøller, John; Larsen, B.

    1983-01-01

    A study of the hydrogenation characteristics of fine magnesium powder during repeated cycling has been performed using a high-pressure microbalance facility. No effect was found from the cycling regarding kinetics and storage capacity. The reaction rate of the absorption process was fast at tempe......A study of the hydrogenation characteristics of fine magnesium powder during repeated cycling has been performed using a high-pressure microbalance facility. No effect was found from the cycling regarding kinetics and storage capacity. The reaction rate of the absorption process was fast...... at temperatures around 600 K and above, but the reversed reaction showed somewhat slower kinetics around 600 K. At higher temperatures the opposite was found. The enthalpy and entropy change by the hydrogenation, derived from pressure-concentration isotherms, agree fairly well with those reported earlier....

  2. Possible health effects of high manganese concentration in drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Kondakis, X.G.; Makris, N.; Leotsinidis, M.; Prinou, M.; Papapetropoulos, T.

    1989-05-01

    Three areas in the same region of northwest Peloponnesos, Greece, that had varying concentrations of manganese (Mn) in drinking water were selected for study. The Mn concentrations in areas A, B, and C were 3.6-14.6 micrograms/l, 81.6-252.6 micrograms/l, and 1 800-2 300 micrograms/l, respectively. A random sample (62 in area A, 49 in area B, and 77 in area C) of males and females who were at least 50 y of age were submitted to a thorough neurological examination and their whole-blood Mn and hair Mn concentrations were determined. Although all areas were similar with respect to social and dietary characteristics, significant differences were observed for prevalence of chronic manganese poisoning (CMnP) symptoms and hair Mn concentration. The means (both sexes) of neurological scores were 2.7, 3.9, and 5.2, respectively, for areas A, B, and C (Kruskal-Wallis, chi 2 = 6.44, 2 df, p less than .05 for males; chi 2 = 7.8, 2 df, p less than .05 for females). Hair Mn concentrations were also significantly different, the means for which were 3.51, 4.49, and 10.99 micrograms/g dry weight, respectively (both sexes (p less than .001 for each sex separately)). These results indicate that progressive increases of Mn concentration in drinking water are associated with progressively higher prevalences of neurological signs of CMnP and Mn concentration in hair of older persons.

  3. The hydrogen issue.

    Science.gov (United States)

    Armaroli, Nicola; Balzani, Vincenzo

    2011-01-17

    Hydrogen is often proposed as the fuel of the future, but the transformation from the present fossil fuel economy to a hydrogen economy will need the solution of numerous complex scientific and technological issues, which will require several decades to be accomplished. Hydrogen is not an alternative fuel, but an energy carrier that has to be produced by using energy, starting from hydrogen-rich compounds. Production from gasoline or natural gas does not offer any advantage over the direct use of such fuels. Production from coal by gasification techniques with capture and sequestration of CO₂ could be an interim solution. Water splitting by artificial photosynthesis, photobiological methods based on algae, and high temperatures obtained by nuclear or concentrated solar power plants are promising approaches, but still far from practical applications. In the next decades, the development of the hydrogen economy will most likely rely on water electrolysis by using enormous amounts of electric power, which in its turn has to be generated. Producing electricity by burning fossil fuels, of course, cannot be a rational solution. Hydroelectric power can give but a very modest contribution. Therefore, it will be necessary to generate large amounts of electric power by nuclear energy of by renewable energies. A hydrogen economy based on nuclear electricity would imply the construction of thousands of fission reactors, thereby magnifying all the problems related to the use of nuclear energy (e.g., safe disposal of radioactive waste, nuclear proliferation, plant decommissioning, uranium shortage). In principle, wind, photovoltaic, and concentrated solar power have the potential to produce enormous amounts of electric power, but, except for wind, such technologies are too underdeveloped and expensive to tackle such a big task in a short period of time. A full development of a hydrogen economy needs also improvement in hydrogen storage, transportation and distribution

  4. Highly efficient photocatalytic hydrogen evolution of graphene/YInO3 nanocomposites under visible light irradiation.

    Science.gov (United States)

    Ding, Jianjun; Yan, Wenhao; Xie, Wei; Sun, Song; Bao, Jun; Gao, Chen

    2014-02-21

    Visible-light-driven hydrogen evolution with high efficiency is important in the current photocatalysis research. Here we report for the first time the design and synthesis of a new graphene-semiconductor nanocomposite consisting of YInO3 nanoparticles and two-dimensional graphene sheets as efficient photocatalysts for hydrogen evolution under visible light irradiation. The graphene/YInO3 nanocomposites were synthesized using a facile solvothermal method in which the formation of graphene and the deposition of YInO3 nanoparticles on the graphene sheets can be achieved simultaneously. The addition of graphene as a cocatalyst can narrow the band gap of YInO3 to visible photon energy and prolong the separation and lifetime of electron-hole pairs by the chemical bonding between YInO3 and graphene. The photocatalytic reaction with this nanocomposite reaches a high H2 evolution rate of 400.4 μmol h(-1) g(-1) when the content of graphene is 0.5 wt%, over 127 and 3.7 times higher than that of pure YInO3 and Pt/YInO3, respectively. This work can provide an effective approach to the fabrication of graphene-based photocatalysts with high performance in the field of energy conversion.

  5. Hydrogen bond based smart polymer for highly selective and tunable capture of multiply phosphorylated peptides.

    Science.gov (United States)

    Qing, Guangyan; Lu, Qi; Li, Xiuling; Liu, Jing; Ye, Mingliang; Liang, Xinmiao; Sun, Taolei

    2017-09-06

    Multisite phosphorylation is an important and common mechanism for finely regulating protein functions and subsequent cellular responses. However, this study is largely restricted by the difficulty to capture low-abundance multiply phosphorylated peptides (MPPs) from complex biosamples owing to the limitation of enrichment materials and their interactions with phosphates. Here we show that smart polymer can serve as an ideal platform to resolve this challenge. Driven by specific but tunable hydrogen bonding interactions, the smart polymer displays differential complexation with MPPs, singly phosphorylated and non-modified peptides. Importantly, MPP binding can be modulated conveniently and precisely by solution conditions, resulting in highly controllable MPP adsorption on material surface. This facilitates excellent performance in MPP enrichment and separation from model proteins and real biosamples. High enrichment selectivity and coverage, extraordinary adsorption capacities and recovery towards MPPs, as well as high discovery rates of unique phosphorylation sites, suggest its great potential in phosphoproteomics studies.Capture of low-abundance multiply phosphorylated peptides (MPPs) is difficult due to limitation of enrichment materials and their interactions with phosphates. Here the authors show, a smart polymer driven by specific but tunable hydrogen bonding interactions can differentially complex with MPPs, singly phosphorylated and non-modified peptides.

  6. Hydrogen bonds of a novel resin cement contribute to high adhesion strength to human dentin.

    Science.gov (United States)

    Wu, Wei-Che; Wang, Da-Ming; Lin, Yu-Chen; Dai, Chi-An; Cheng, Kuo-Chung; Hu, Mei-Shan; Lee, Bor-Shiunn

    2016-01-01

    The detachment of fiber posts from root canals is primarily caused by the loss of adhesion between dentin and cement; therefore, the purpose of this study was to formulate a novel resin cement that improves the bond strength of fiber posts to the dentin-cement interface. Three concentrations (30, 35, and 40wt.%) of bis[2-(methacryloyloxy)-ethyl] phosphate (2MP) were prepared as dentin bonding agent components. Isobornyl acrylate (IBOA) and ethylhexylacrylate (EHA) were used as key components to fabricate the resin cement (named IE cement). The adhesive strengths of IE cement to coronal and root canal dentin were tested after placement of specimens in a water bath at 100% humidity and 37°C for either 24h or 5 months. The microtensile bond test, the push-out bond test, and the fracture toughness test were performed. Four commercially available resin cements (Nexus(®) third generation (NX3), Variolink II, RelyX Unicem, and Panavia F 2.0) were used for comparisons. X-ray photoelectron spectroscopy (XPS) was used to analyze the interaction of collagen extracted from human dentin and 2MP as well as the fracture surfaces of the specimens submitted to the microtensile bond test. The 35% concentration of 2MP, in combination with IBOA and EHA, was the most effective for improving the IE cement's bond strength to dentin. The XPS results revealed that the phosphate groups of 2MP formed hydrogen bonds with the collagen and that such bonds prominently decreased in number in the specimens that were stored for 5 months. The combination of 2MP, IBOA, and EHA can effectively increase the adhesive strength of IE cement to dentin via hydrogen bond formation. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  7. Development of manufacturing capability for high-concentration, high-efficiency silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sinton, R.A.; Verlinden, P.J.; Crane, R.A.; Swanson, R.N. [SunPower Corp., Sunnyvale, CA (United States)

    1996-10-01

    This report presents a summary of the major results from a program to develop a manufacturable, high-efficiency silicon concentrator solar cell and a cost-effective manufacturing facility. The program was jointly funded by the Electric Power Research Institute, Sandia National Laboratories through the Concentrator Initiative, and SunPower Corporation. The key achievements of the program include the demonstration of 26%-efficient silicon concentrator solar cells with design-point (20 W/cm{sup 2}) efficiencies over 25%. High-performance front-surface passivations; that were developed to achieve this result were verified to be absolutely stable against degradation by 475 days of field exposure at twice the design concentration. SunPower demonstrated pilot production of more than 1500 of these cells. This cell technology was also applied to pilot production to supply 7000 17.7-cm{sup 2} one-sun cells (3500 yielded wafers) that demonstrated exceptional quality control. The average efficiency of 21.3% for these cells approaches the peak efficiency ever demonstrated for a single small laboratory cell within 2% (absolute). Extensive cost models were developed through this program and calibrated by the pilot-production project. The production levels achieved indicate that SunPower could produce 7-10 MW of concentrator cells per year in the current facility based upon the cell performance demonstrated during the program.

  8. Highly Sensitive Cadmium Concentration Sensor Using Long Period Grating

    Directory of Open Access Journals (Sweden)

    A. S. Lalasangi

    2011-08-01

    Full Text Available In this paper we have proposed a simple and effective Long Period Grating chemical sensor for detecting the traces of Cadmium (Cd++ in drinking water at ppm level. Long Period gratings (LPG were fabricated by point-by-point technique with CO2 laser. We have characterized the LPG concentration sensor sensitivity for different solutions of Cd concentrations varying from 0.01 ppm to 0.04 ppm by injecting white Light source and observed transmitted spectra using Optical Spectrum Analyzer (OSA. Proper reagents have been used in the solutions for detection of the Cd species. The overall shift in wavelength is 10 nm when surrounding medium gradually changed from water to 0.04 ppm of cadmium concentrations. A comparative study has been done using sophisticated spectroscopic atomic absorption spectrometer (AAS and Inductively Coupled Plasma (ICP instruments. The spectral sensitivity enhancement was done by modifying grating surface with gold nanoparticles.

  9. Methods and devices for high-throughput dielectrophoretic concentration

    Science.gov (United States)

    Simmons, Blake A.; Cummings, Eric B.; Fiechtner, Gregory J.; Fintschenko, Yolanda; McGraw, Gregory J.; Salmi, Allen

    2010-02-23

    Disclosed herein are methods and devices for assaying and concentrating analytes in a fluid sample using dielectrophoresis. As disclosed, the methods and devices utilize substrates having a plurality of pores through which analytes can be selectively prevented from passing, or inhibited, on application of an appropriate electric field waveform. The pores of the substrate produce nonuniform electric field having local extrema located near the pores. These nonuniform fields drive dielectrophoresis, which produces the inhibition. Arrangements of electrodes and porous substrates support continuous, bulk, multi-dimensional, and staged selective concentration.

  10. A multiphase mixture model for substrate concentration distribution characteristics and photo-hydrogen production performance of the entrapped-cell photobioreactor.

    Science.gov (United States)

    Guo, Cheng-Long; Cao, Hong-Xia; Pei, Hong-Shan; Guo, Fei-Qiang; Liu, Da-Meng

    2015-04-01

    A multiphase mixture model was developed for revealing the interaction mechanism between biochemical reactions and transfer processes in the entrapped-cell photobioreactor packed with gel granules containing Rhodopseudomonas palustris CQK 01. The effects of difference operation parameters, including operation temperature, influent medium pH value and porosity of packed bed, on substrate concentration distribution characteristics and photo-hydrogen production performance were investigated. The results showed that the model predictions were in good agreement with the experimental data reported. Moreover, the operation temperature of 30 °C and the influent medium pH value of 7 were the most suitable conditions for photo-hydrogen production by biodegrading substrate. In addition, the lower porosity of packed bed was beneficial to enhance photo-hydrogen production performance owing to the improvement on the amount of substrate transferred into gel granules caused by the increased specific area for substrate transfer in the elemental volume. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Molybdenum disulfide nanoparticles decorated reduced graphene oxide: highly sensitive and selective hydrogen sensor

    Science.gov (United States)

    Venkatesan, A.; Rathi, Servin; Lee, In-yeal; Park, Jinwoo; Lim, Dongsuk; Kang, Moonshik; Joh, Han-Ik; Kim, Gil-Ho; Kannan, E. S.

    2017-09-01

    In this work, we report on the hydrogen (H2) sensing behavior of reduced graphene oxide (RGO)/molybdenum disulfide (MoS2) nano particles (NPs) based composite film. The RGO/MoS2 composite exhibited a highly enhanced H2 response (∼15.6%) for 200 ppm at an operating temperature of 60 °C. Furthermore, the RGO/MoS2 composite showed excellent selectivity to H2 with respect to ammonia (NH3) and nitric oxide (NO) which are highly reactive gas species. The composite’s response to H2 is 2.9 times higher than that of NH3 whereas for NO it is 3.5. This highly improved H2 sensing response and selectivity of RGO/MoS2 at low operating temperatures were attributed to the structural integration of MoS2 nanoparticles in the nanochannels and pores in the RGO layer.

  12. High pressure inertial focusing for separation and concentration of bacteria at high throughput

    Science.gov (United States)

    Cruz, F. J.; Hjort, K.

    2017-11-01

    Inertial focusing is a phenomenon where particles migrate across streamlines in microchannels and focus at well-defined, size dependent equilibrium points of the cross section. It can be taken into advantage for focusing, separation and concentration of particles at high through-put and high efficiency. As particles decrease in size, smaller channels and higher pressures are needed. Hence, new designs are needed to decrease the pressure drop. In this work a novel design was adapted to focus and separate 1 µm from 3 µm spherical polystyrene particles. Also 0.5 µm spherical polystyrene particles were separated, although in a band instead of a single line. The ability to separate, concentrate and focus bacteria, its simplicity of use and high throughput make this technology a candidate for daily routines in laboratories and hospitals.

  13. Energetic multifunctionalized nitraminopyrazoles and their ionic derivatives: ternary hydrogen-bond induced high energy density materials.

    Science.gov (United States)

    Yin, Ping; Parrish, Damon A; Shreeve, Jean'ne M

    2015-04-15

    Diverse functionalization was introduced into the pyrazole framework giving rise to a new family of ternary hydrogen-bond induced high energy density materials. By incorporating extended cationic interactions, nitramine-based ionic derivatives exhibit good energetic performance and enhanced molecular stability. Performance parameters including heats of formation and detonation properties were calculated by using Gaussian 03 and EXPLO5 v6.01 programs, respectively. It is noteworthy to find that 5-nitramino-3,4-dinitropyrazole, 4, has a remarkable measured density of 1.97 g cm(-3) at 298 K, which is consistent with its crystal density (2.032 g cm(-3), 150 K), and ranks highest among azole-based CHNO compounds. Energetic evaluation indicates that, in addition to the molecular compound 4, some ionic derivatives, 9, 11, 12, 17, 19, and 22, also have high densities (1.83-1.97 g cm(-3)), excellent detonation pressures and velocities (P, 35.6-41.6 GPa; vD, 8880-9430 m s(-1)), as well as acceptable impact and friction sensitivities (IS, 4-30 J; FS, 40-240 N). These attractive features highlight the application potential of nitramino hydrogen-bonded interactions in the design of advanced energetic materials.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Storage of hydrogen in advanced high pressure container. Appendices; Lagring af brint i avancerede hoejtryksbeholdere. Appendiks 1

    Energy Technology Data Exchange (ETDEWEB)

    Bentzen, J.J.; Lystrup, A. [Forskningscenter Risoe, Roskilde (Denmark)

    2005-07-15

    The objective of the project has been to study barriers for a production of advanced high pressure containers especially suitable for hydrogen, in order to create a basis for a container production in Denmark. The project has primarily focused on future Danish need for hydrogen storage in the MWh area. One task has been to examine requirement specifications for pressure tanks that can be expected in connection with these stores. Six potential storage needs have been identified: (1) Buffer in connection with start-up/regulation on the power grid. (2) Hydrogen and oxygen production. (3) Buffer store in connection with VEnzin vision. (4) Storage tanks on hydrogen filling stations. (5) Hydrogen for the transport sector from 1 TWh surplus power. (6) Tanker transport of hydrogen. Requirements for pressure containers for the above mentioned use have been examined. The connection between stored energy amount, pressure and volume compared to liquid hydrogen and oil has been stated in tables. As starting point for production technological considerations and economic calculations of various container concepts, an estimation of laminate thickness in glass-fibre reinforced containers with different diameters and design print has been made, for a 'pure' fibre composite container and a metal/fibre composite container respectively. (BA)

  16. Hydrogen exchange

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Rand, Kasper Dyrberg

    2016-01-01

    Hydrogen exchange (HX) monitored by mass spectrometry (MS) is a powerful analytical method for investigation of protein conformation and dynamics. HX-MS monitors isotopic exchange of hydrogen in protein backbone amides and thus serves as a sensitive method for probing protein conformation...... and dynamics along the entire protein backbone. This chapter describes the exchange of backbone amide hydrogen which is highly quenchable as it is strongly dependent on the pH and temperature. The HX rates of backbone amide hydrogen are sensitive and very useful probes of protein conformation......, as they are distributed along the polypeptide backbone and form the fundamental hydrogen-bonding networks of basic secondary structure. The effect of pressure on HX in unstructured polypeptides (poly-dl-lysine and oxidatively unfolded ribonuclease A) and native folded proteins (lysozyme and ribonuclease A) was evaluated...

  17. High urinary phthalate concentration associated with delayed pubarche in girls

    DEFF Research Database (Denmark)

    Frederiksen, H; Sørensen, K; Mouritsen, A

    2012-01-01

    in pubertal timing among girls, although controversies exist. We determined the concentration of 12 phthalate metabolites in first morning urine samples from 725 healthy Danish girls (aged 5.6-19.1 years) in relation to age, pubertal development (breast and pubic hair stage) and reproductive hormone levels...... (luteinizing hormone, oestradiol and testosterone). Furthermore, urinary phthalates were determined in 25 girls with precocious puberty (PP). In general, the youngest girls with less advanced pubertal development had the highest first morning urinary concentration of the monobutyl phthalate isoforms (¿MBP......). This trend was statistically significant when all phthalate metabolites (except MEP) were summarized and expressed as quartiles. No association between phthalates and breast development was observed. In addition, there were no differences in urinary phthalate metabolite levels between girls with PP...

  18. Highly Concentrated Seed Mediated Synthesis of Monodispersed Gold Nanorods (Postprint)

    Science.gov (United States)

    2017-07-17

    resolution TEM images (Figure 5c) also confirm that the single crystalline structures of Au-NRs from this process production is identical to that of... structural characteristics of the Au NR product. The volume of seed solution is varied from 1S to 500S and reactant concentration was increased from 1G to... TEM images of Au-NRs obtained from different condition. The scale bar is 100 nm. ACS Applied Materials & Interfaces Research Article DOI: 10.1021

  19. Nitrobacter winogradskyi transcriptomic response to low and high ammonium concentrations.

    Science.gov (United States)

    Sayavedra-Soto, Luis; Ferrell, Rebecca; Dobie, Michael; Mellbye, Brett; Chaplen, Frank; Buchanan, Alex; Chang, Jeffrey; Bottomley, Peter; Arp, Daniel

    2015-01-01

    Nitrobacter winogradskyi Nb-255 is a nitrite-oxidizing bacterium that can grow solely on nitrite (NO2(-)) as a source of energy and nitrogen. In most natural situations, NO2(-) oxidation is coupled closely to ammonium (NH4(+)) oxidation by bacteria and archaea and, conceptually, N. winogradskyi can save energy using NH4(+) to meet its N-biosynthetic requirements. Interestingly, NH4(+) delayed the growth of N. winogradskyi when at concentrations higher than 35 mM, but grew well at concentrations below 25 mM NH4(+) while adjusting the expression of 24% of its genes. Notable genes that changed in expression included those with roles in nitrogen and carbon assimilation. Contrary to expectations, higher expression of glutamate synthase (GOGAT), instead of glutamate dehydrogenase, was detected at higher NH4(+) concentration. Genes in assimilatory NO2(-) metabolism and the degradation of glycogen and biofilm/motility were downregulated when N. winogradskyi was grown in the presence of NH4(+). Nitrobacter winogradskyi grown in medium with 25 mM NH4(+) upregulated genes in post-translational modification, protein turnover, biogenesis and chaperons. The data suggest that N. winogradskyi physiology is modified in the presence of NH4(+) and is likely to be modified during coupled nitrification with NH3 oxidizers. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. High concentrations of pepsin in bronchoalveolar lavage fluid from children with cystic fibrosis are associated with high interleukin-8 concentrations.

    LENUS (Irish Health Repository)

    McNally, P

    2012-02-01

    BACKGROUND: Gastro-oesophageal reflux is common in children with cystic fibrosis (CF) and is thought to be associated with pulmonary aspiration of gastric contents. The measurement of pepsin in bronchoalveolar lavage (BAL) fluid has recently been suggested to be a reliable indicator of aspiration. The prevalence of pulmonary aspiration in a group of children with CF was assessed and its association with lung inflammation investigated. METHODS: This was a cross-sectional case-control study. BAL fluid was collected from individuals with CF (n=31) and healthy controls (n=7). Interleukin-8 (IL-8), pepsin, neutrophil numbers and neutrophil elastase activity levels were measured in all samples. Clinical, microbiological and lung function data were collected from medical notes. RESULTS: The pepsin concentration in BAL fluid was higher in the CF group than in controls (mean (SD) 24.4 (27.4) ng\\/ml vs 4.3 (4.0) ng\\/ml, p=0.03). Those with CF who had raised pepsin concentrations had higher levels of IL-8 in the BAL fluid than those with a concentration comparable to controls (3.7 (2.7) ng\\/ml vs 1.4 (0.9) ng\\/ml, p=0.004). Within the CF group there was a moderate positive correlation between pepsin concentration and IL-8 in BAL fluid (r=0.48, p=0.04). There was no association between BAL fluid pepsin concentrations and age, sex, body mass index z score, forced expiratory volume in 1 s or Pseudomonas aeruginosa colonisation status. CONCLUSIONS: Many children with CF have increased levels of pepsin in the BAL fluid compared with normal controls. Increased pepsin levels were associated with higher IL-8 concentrations in BAL fluid. These data suggest that aspiration of gastric contents occurs in a subset of patients with CF and is associated with more pronounced lung inflammation.

  1. Metal-organic framework based highly selective fluorescence turn-on probe for hydrogen sulphide

    Science.gov (United States)

    Nagarkar, Sanjog S.; Saha, Tanmoy; Desai, Aamod V.; Talukdar, Pinaki; Ghosh, Sujit K.

    2014-11-01

    Hydrogen sulphide (H2S) is known to play a vital role in human physiology and pathology which stimulated interest in understanding complex behaviour of H2S. Discerning the pathways of H2S production and its mode of action is still a challenge owing to its volatile and reactive nature. Herein we report azide functionalized metal-organic framework (MOF) as a selective turn-on fluorescent probe for H2S detection. The MOF shows highly selective and fast response towards H2S even in presence of other relevant biomolecules. Low cytotoxicity and H2S detection in live cells, demonstrate the potential of MOF towards monitoring H2S chemistry in biological system. To the best of our knowledge this is the first example of MOF that exhibit fast and highly selective fluorescence turn-on response towards H2S under physiological conditions.

  2. Appraisal of the realistic accuracy of molecular dynamics of high-pressure hydrogen

    Directory of Open Access Journals (Sweden)

    Graeme J. Ackland

    2015-12-01

    Full Text Available Molecular dynamics (MD is a powerful method for studying the behaviour of materials at high temperature. In practice, however, its effectiveness in representing real systems is limited by the accuracy of the forces, finite size effects, quantization and equilibration methods. In this paper, we report and discuss some calculations carried out using MD on high-pressure hydrogen, reviewing a number of sources of error, of which the neglect of zero-point vibrations is quantitatively the largest. We show that simulations using ab initio MD with the PBE functional predict a large stability field for the molecular Cmca4 structure at pressures just above those achieved in current experiments above the stability range of the mixed molecular layered Phase IV. However, the various errors in the simulation all point towards a much smaller stability range, and the likelihood of a non-molecular phase based on low-coordination networks or chains of atoms.

  3. High precision X-ray spectroscopy in hydrogen-like fermionic and bosonic atomic systems

    Energy Technology Data Exchange (ETDEWEB)

    Borchert, G.L.; Anagnostopoulos, D.; Augsburger, M.; Belmiloud, D.; Castelli, C.; Chatellard, D.; Daum, M.; Egger, J.P.; El-Khoury, P.; Elble, M.; Frosch, R.; Gorke, H.; Gotta, D.; Hauser, P.; Indelicato, P.; Kirch, K.; Lenz, S.; Nelms, N.; Rashid, K.; Schult, O.W.B. (and others)

    1998-11-15

    Some time after its formation an exotic atom may be considered a hydrogen-like system consisting of a nucleus and an exotic particle in a bound state. In this situation it is an ideal tool to study cascade properties, while for the innermost orbits it can be used to probe the interaction with the nucleus. From an extended series of experiments using high resolution X-ray spectroscopy for both aspects typical examples are reported and preliminary results are given: 1. To determine the complex scattering length in p-barH the 3D{yields}2P hyperfine transitions have been measured. 2. To determine the pion mass the 5 {yields} 4 transitions in {pi}{sup 14}N have been studied. In all cases a major contribution to the uncertainty originates from the calibration. Therefore a new method is proposed that will establish a universal set of high precision calibration lines for pionic, muonic and electronic systems.

  4. High-resolution NMR of hydrogen in organic solids by DNP enhanced natural abundance deuterium spectroscopy.

    Science.gov (United States)

    Rossini, Aaron J; Schlagnitweit, Judith; Lesage, Anne; Emsley, Lyndon

    2015-10-01

    We demonstrate that high field (9.4 T) dynamic nuclear polarization (DNP) at cryogenic (∼100 K) sample temperatures enables the rapid acquisition of natural abundance (1)H-(2)H cross-polarization magic angle spinning (CPMAS) solid-state NMR spectra of organic solids. Spectra were obtained by impregnating substrates with a solution of the stable DNP polarizing agent TEKPol in tetrachloroethane. Tetrachloroethane is a non-solvent for the solids, and the unmodified substrates are then polarized through spin diffusion. High quality natural abundance (2)H CPMAS spectra of histidine hydrochloride monohydrate, glycylglycine and theophylline were acquired in less than 2h, providing direct access to hydrogen chemical shifts and quadrupolar couplings. The spectral resolution of the (2)H solid-state NMR spectra is comparable to that of (1)H spectra obtained with state of the art homonuclear decoupling techniques. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  5. High pressure inertial focusing for separating and concentrating bacteria at high throughput

    Science.gov (United States)

    Cruz, J.; Hooshmand Zadeh, S.; Graells, T.; Andersson, M.; Malmström, J.; Wu, Z. G.; Hjort, K.

    2017-08-01

    Inertial focusing is a promising microfluidic technology for concentration and separation of particles by size. However, there is a strong correlation of increased pressure with decreased particle size. Theory and experimental results for larger particles were used to scale down the phenomenon and find the conditions that focus 1 µm particles. High pressure experiments in robust glass chips were used to demonstrate the alignment. We show how the technique works for 1 µm spherical polystyrene particles and for Escherichia coli, not being harmful for the bacteria at 50 µl min-1. The potential to focus bacteria, simplicity of use and high throughput make this technology interesting for healthcare applications, where concentration and purification of a sample may be required as an initial step.

  6. Hydrogen-induced cold cracking in heat-affected zone of low-carbon high-strength steel

    Science.gov (United States)

    Lan, Liangyun; Kong, Xiangwei; Hu, Zhiyong; Qiu, Chunlin

    2014-12-01

    The Y-groove cracking test by submerged arc welding was employed to study the susceptibility of a low-carbon high-strength steel to hydrogen-induced cold cracking (HICC). The morphology of hydrogen cracks was observed using an electron probe microscope. The results showed that the heat-affected zone (HAZ) has a higher susceptibility to HICC than the weld metal and that increasing heat input can improve the HICC resistance of the weldment. The intergranular microcracking is the main HICC mode at the lowest heat input condition, accompanied with some transgranular microcracks attached to complex inclusions. In combination with phase transformation behaviour in sub-zones, the effect of the phase transformation sequence is proposed to try to illustrate the fact that the fine-grained HAZ has higher probability of hydrogen cracking than the coarse-grained HAZ owing to the occurrence of hydrogen enrichment in the fine-grained HAZ after the transformation.

  7. High Growth Rate Deposition of Hydrogenated Amorphous Silicon-Germanium Films and Devices Using ECR-PECVD

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yong [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    Hydrogenated amorphous silicon germanium films (a-SiGe:H) and devices have been extensively studied because of the tunable band gap for matching the solar spectrum and mature the fabrication techniques. a-SiGe:H thin film solar cells have great potential for commercial manufacture because of very low cost and adaptability to large-scale manufacturing. Although it has been demonstrated that a-SiGe:H thin films and devices with good quality can be produced successfully, some issues regarding growth chemistry have remained yet unexplored, such as the hydrogen and inert-gas dilution, bombardment effect, and chemical annealing, to name a few. The alloying of the SiGe introduces above an order-of-magnitude higher defect density, which degrades the performance of the a-SiGe:H thin film solar cells. This degradation becomes worse when high growth-rate deposition is required. Preferential attachment of hydrogen to silicon, clustering of Ge and Si, and columnar structure and buried dihydride radicals make the film intolerably bad. The work presented here uses the Electron-Cyclotron-Resonance Plasma-Enhanced Chemical Vapor Deposition (ECR-PECVD) technique to fabricate a-SiGe:H films and devices with high growth rates. Helium gas, together with a small amount of H2, was used as the plasma species. Thickness, optical band gap, conductivity, Urbach energy, mobility-lifetime product, I-V curve, and quantum efficiency were characterized during the process of pursuing good materials. The microstructure of the a-(Si,Ge):H material was probed by Fourier-Transform Infrared spectroscopy. They found that the advantages of using helium as the main plasma species are: (1) high growth rate--the energetic helium ions break the reactive gas more efficiently than hydrogen ions; (2) homogeneous growth--heavy helium ions impinging on the surface promote the surface mobility of the reactive radicals, so that heteroepitaxy growth as clustering of Ge and Si, columnar structure are

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

    Science.gov (United States)

    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.

  9. High-energy-density hydrogen-halogen fuel cells for advanced military applications

    Science.gov (United States)

    Balko, E. N.; McElroy, J. F.

    It is pointed out that hydrogen-halogen fuel cell systems are particularly suited for an employment as ground power sources for military applications. The large cell potential and reversible characteristics of the H2/Cl2 and H2/Br2 couples permit high energy storage density and efficient energy conversion. When used as flow batteries, the fluid nature of the reactants in the hydrogen-halogen systems has several advantages over power sources which involve solid phases. Very deep discharge is possible without degradation of subsequent performance, and energy storage capacity is limited only by the external reactant storage volume. Very rapid chemical recharging is possible through replenishment of the reactant supply. A number of H2/Cl2 and H2/Br2 fuel cell systems have been studied. These systems use the same solid polymer electrolyte (SPE) cell technology originally developed for H2/O2 fuel cells. The results of the investigation are illustrated with the aid of a number of graphs.

  10. High-Efficiently Photoelectrochemical Hydrogen Production over Zn-Incorporated TiO2 Nanotubes

    Directory of Open Access Journals (Sweden)

    Gayoung Lee

    2012-01-01

    Full Text Available To investigate the Zn dopant and nanotube morphology effects of TiO2 in electrochemical hydrogen production from the photo-splitting of methanol/water solution, we have designed a Zn-incorporated TiO2 nanotube (Zn-TNT photocatalyst. The TNT and Zn-TNT materials had a width of 70~100 nm. The hydrogen production over the Zn-TNT photocatalysts was higher than that over the TNT; specifically, 10.2 mL of H2 gas was produced after 9 hours when 0.5 g of 0.01 mol% Zn-TNT was used. The zeta-potential values in aqueous solution determined by electrophoretic light scattering (ELS had negative surface charges, which was related to the surface stability, and the absolute value was the largest in 0.01 mol% Zn-TNT. On the basis of UV-visible and photoluminescence (PL spectra results, the high photoactivity of Zn-TNT was attributed to the shift toward the visible region and increase of PL intensity due to the increased number of excited electrons and holes.

  11. High sensitivity hydrogen sensing with Pt-decorated porous gallium nitride prepared by metal-assisted electroless etching.

    Science.gov (United States)

    Duan, Barrett K; Bohn, Paul W

    2010-05-01

    A unique hydrogen sensor structure based on Pt-decorated porous gallium nitride (PGaN) was fabricated by a two-step process consisting of metal-assisted electroless etching to produce PGaN with highly anisotropic pores followed by electroless deposition of Pt in the pores from an ammoniacal PtCl(6)(2-) solution. The Pt-decorated PGaN structure contains 50-100 nm diameter nanopores which are 400 nm to 1 microm deep and filled with Pt islands. Both electroless etching and deposition steps are done in solution and allow for large-scale production. An AC four-point probe conductivity measurement was implemented at f = 1 kHz, a frequency where the impedance of Pt-PGaN is nearly entirely resistive, and the change in conductance upon H(2) exposure was measured for three sample types: PGaN with a surface sputtered layer of Pt only; unetched GaN (CGaN) with both sputtered and electrolessly deposited Pt; and PGaN with both sputtered and electrolessly deposited Pt. The hydrogen sensing performance of the Pt-filled PGaN sensor was more than an order of magnitude better than either of the other two sample types under all experimental conditions, an observation attributed to the significant increase in Pt-GaN interfacial area in the electrolessly decorated PGaN samples, exhibiting a response to H2 concentrations as low as 1 ppm. The conductance changes are ascribed to adsorption-induced changes in interfacial polarization that produce changes in band bending and thus to the width of the space charge region near the Pt-GaN interface.

  12. High-performance flat-panel solar thermoelectric generators with high thermal concentration.

    Science.gov (United States)

    Kraemer, Daniel; Poudel, Bed; Feng, Hsien-Ping; Caylor, J Christopher; Yu, Bo; Yan, Xiao; Ma, Yi; Wang, Xiaowei; Wang, Dezhi; Muto, Andrew; McEnaney, Kenneth; Chiesa, Matteo; Ren, Zhifeng; Chen, Gang

    2011-05-01

    The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1 kW m(-2)) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity. © 2011 Macmillan Publishers Limited. All rights reserved

  13. New PSA high concentration solar furnace SF40

    Science.gov (United States)

    Rodriguez, Jose; Cañadas, Inmaculada; Zarza, Eduardo

    2016-05-01

    A new solar furnace has been designed and built at Plataforma Solar de Almería. In this work, its main components such as heliostat, concentrator, attenuator and test table, and the method used to align them are described. Other equipment like the auxiliary systems necessary for the solar operation, vacuum chamber and gas system are outlined too. Finally, the thermal characteristics of the focus were measured during a test campaign, where different planes along the optical axis were scanned with a radiometer, and the peak flux was obtained and is presented in the last section of this report.

  14. The anaesthesia of fish by high carbon-dioxide concentrations

    Science.gov (United States)

    1942-01-01

    A practical and economical method for anaesthetizing adult salmon and steelhead trout in the fish trucks used in the Grand Coulee fish salvage program is described. The method consists in generating a predetermined carbon-dioxide concentration in the 1000-gallon tanks of the trucks through the successive addition of predissolved sodium bicarbonate and dilute sulphuric acid in proper quantities. Carbon-dioxide anaesthesia effectively solved the acute problem of species segregation in the fish salvage program and, with minor modifications, could be used with equal success in certain hatchery operations necessitating the handling of large fish.

  15. Molecular hydrogen: a therapeutic antioxidant and beyond

    Directory of Open Access Journals (Sweden)

    Lei Huang

    2016-01-01

    Full Text Available Molecular hydrogen (H2 medicine research has flourished since a landmark publication in Nature Medicine that revealed the antioxidant and cytoprotective effects of hydrogen gas in a focal stroke model. Emerging evidence has consistently demonstrated that molecular hydrogen is a promising therapeutic option for a variety of diseases and the underlying comprehensive mechanisms is beyond pure hydroxyl radicals scavenging. The non-toxicity at high concentrations and rapid cellular diffusion features of molecular hydrogen ensure the feasibility and readiness of its clinical translation to human patients.

  16. FINAL REPORT - Development of High Pressure Hydrogen Storage Tank for Storage and Gaseous Truck Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, Donald [Hexagon Lincoln LLC, Lincoln, NE (United States)

    2017-08-04

    The “Development of High Pressure Hydrogen Storage Tanks for Storage and Gaseous Truck Delivery” project [DE-FG36-08GO18062] was initiated on 01 July 2008. Hexagon Lincoln (then Lincoln Composites) received grant funding from the U.S. Department of Energy to support the design and development of an improved bulk hauling and storage solution for hydrogen in terms of cost, safety, weight and volumetric efficiency. The development of this capability required parallel development and qualification of large all-composites pressure vessels, a custom ISO container to transport and store said tanks, and performance of trade studies to identify optimal operating pressure for the system. Qualification of the 250 bar TITAN® module was completed in 2009 with supervision from the American Bureau of Shipping [ABS], and the equipment has been used internationally for bulk transportation of fuel gases since 2010. Phase 1 of the project was successfully completed in 2012 with the issuance of USDOT SP 14951, the special permit authorizing the manufacture, marking, sale and use of TITAN® Mobile Pipeline® equipment in the United States. The introduction of tube trailers with light weight composite tankage has meant that 2 to 3 times as much gaseous fuel can be transported with each trip. This increased hauling efficiency offers dramatically reduced operating costs and has enabled a profitable business model for over-the-road compressed natural gas delivery. The economic drivers of this business opportunity vary from country to country and region to region, but in many places gas distribution companies have realized profitable operations. Additional testing was performed in 2015 to characterize hydrogen-specific operating protocols for use of TITAN® systems in CHG service at 250 bar. This program demonstrated that existing compression and decompression methodologies can efficiently and safely fill and unload lightweight bulk hauling systems. Hexagon Lincoln and U.S. DOE agreed

  17. Fe(III)-functionalized carbon dots—Highly efficient photoluminescence redox catalyst for hydrogenations of olefins and decomposition of hydrogen peroxide

    KAUST Repository

    Bourlinos, Athanasios B.

    2017-03-21

    We present the first bottom-up approach to synthesize Fe(III)-functionalized carbon dots (CDs) from molecular precursors without the need of conventional thermal or microwave treatment and additional reagents. Specifically, sonication of xylene in the presence of anhydrous FeCl3 results in oxidative coupling of the aromatic substrate towards Fe(III)-functionalized CDs. The as-prepared CDs are spherical in shape with a size of 3–8 nm, highly dispersible in organic solvents and display wavelength-dependent photoluminescence (PL). The iron ions attached to the surface endow the CDs with superior catalytic activity for olefin hydrogenation with excellent conversion and selectivity (up to 100%). The Fe(III)-CDs are more effective in the hydrogenation of a series of electron donating or withdrawing olefin substrates compared to conventional homogeneous or heterogeneous Fe(III)-based catalysts. The as-prepared heterogeneous nanocatalyst can be used repeatedly without any loss of catalytic activity. Importantly, the stability of the new catalysts can be easily monitored by PL intensity or quantum yield measurements, which certainly opens the doors for real time monitoring in a range of applications. Additionally, to the best of our knowledge, for the first time, the oxidative property of Fe-CDs was also explored in decomposition of hydrogen peroxide in water with the first order rate constant of 0.7 × 10−2 min−1, proving the versatile catalytic properties of such hybrid systems.

  18. Declines in insectivorous birds are associated with high neonicotinoid concentrations.

    Science.gov (United States)

    Hallmann, Caspar A; Foppen, Ruud P B; van Turnhout, Chris A M; de Kroon, Hans; Jongejans, Eelke

    2014-07-17

    Recent studies have shown that neonicotinoid insecticides have adverse effects on non-target invertebrate species. Invertebrates constitute a substantial part of the diet of many bird species during the breeding season and are indispensable for raising offspring. We investigated the hypothesis that the most widely used neonicotinoid insecticide, imidacloprid, has a negative impact on insectivorous bird populations. Here we show that, in the Netherlands, local population trends were significantly more negative in areas with higher surface-water concentrations of imidacloprid. At imidacloprid concentrations of more than 20 nanograms per litre, bird populations tended to decline by 3.5 per cent on average annually. Additional analyses revealed that this spatial pattern of decline appeared only after the introduction of imidacloprid to the Netherlands, in the mid-1990s. We further show that the recent negative relationship remains after correcting for spatial differences in land-use changes that are known to affect bird populations in farmland. Our results suggest that the impact of neonicotinoids on the natural environment is even more substantial than has recently been reported and is reminiscent of the effects of persistent insecticides in the past. Future legislation should take into account the potential cascading effects of neonicotinoids on ecosystems.

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Production of high concentrations of H2O2 in a bioelectrochemical reactor fed with real municipal wastewater.

    Science.gov (United States)

    Modin, Oskar; Fukushi, Kensuke

    2013-01-01

    Bioelectrochemical systems can be used to energy-efficiently produce hydrogen peroxide (H2O2) from wastewater. Organic compounds in the wastewater are oxidized by microorganisms using the anode as electron acceptor. H2O2 is produced by reduction of oxygen on the cathode. In this study, we demonstrate for the first time production of high concentrations of H2O2 production from real municipal wastewater. A concentration of 2.26 g/L H2O2 was produced in 9 h at 8.3 kWh/kgH2O2. This concentration could potentially be useful for membrane cleaning at membrane bioreactor wastewater treatment plants. With an acetate-containing nutrient medium as anode feed, a H2O2 concentration of 9.67 g/L was produced in 21 h at an energy cost of 3.0 kWh/kgH2O2. The bioelectrochemical reactor used in this study suffered from a high internal resistance, most likely caused by calcium carbonate deposits on the cathode-facing side of the cation exchange membrane separating the anode and cathode compartments.

  1. Nano-ferrites for water splitting: Unprecedented high photocatalytic hydrogen production under visible light

    KAUST Repository

    Mangrulkar, Priti A.

    2012-01-01

    In the present investigation, hydrogen production via water splitting by nano-ferrites was studied using ethanol as the sacrificial donor and Pt as co-catalyst. Nano-ferrite is emerging as a promising photocatalyst with a hydrogen evolution rate of 8.275 μmol h -1 and a hydrogen yield of 8275 μmol h -1 g -1 under visible light compared to 0.0046 μmol h -1 for commercial iron oxide (tested under similar experimental conditions). Nano-ferrites were tested in three different photoreactor configurations. The rate of hydrogen evolution by nano-ferrite was significantly influenced by the photoreactor configuration. Altering the reactor configuration led to sevenfold (59.55 μmol h -1) increase in the hydrogen evolution rate. Nano-ferrites have shown remarkable stability in hydrogen production up to 30 h and the cumulative hydrogen evolution rate was observed to be 98.79 μmol h -1. The hydrogen yield was seen to be influenced by several factors like photocatalyst dose, illumination intensity, irradiation time, sacrificial donor and presence of co-catalyst. These were then investigated in detail. It was evident from the experimental data that nano-ferrites under optimized reaction conditions and photoreactor configuration could lead to remarkable hydrogen evolution activity under visible light. Temperature had a significant role in enhancing the hydrogen yield. © 2012 The Royal Society of Chemistry.

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

    Energy Technology Data Exchange (ETDEWEB)

    Pintauro, Peter [Vanderbilt Univ., Nashville, TN (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    W. Hua

    2008-11-01

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

  4. High Energy Density Lithium Air Batteries for Oxygen Concentrators Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For NASA's Exploration Medical Capabilities mission, extremely high specific energy power sources, with specific energy over 2000 Wh/kg, are urgently sought after....

  5. Athletic activity and hormone concentrations in high school female athletes

    National Research Council Canada - National Science Library

    Wojtys, Edward M; Jannausch, Mary L; Kreinbrink, Jennifer L; Harlow, Siobán D; Sowers, MaryFran R

    2015-01-01

    .... To test the hypotheses that (1) the estradiol-progesterone profile of high school adolescent girls participating in training, conditioning, and competition would differ from that of physically inactive, age-matched adolescent girls...

  6. Large scintillation cells for high sensitivity radon concentration measurements

    Science.gov (United States)

    Cohen, B. L.; El Ganayni, M.; Cohen, E. S.

    1983-07-01

    Methods for improving the sensitivity of scintillation cells for radon concentration measurements were studied with emphasis on improving light collection efficiency. This allows the length and hence the volume of the cell to be increased. Variables studied were choice of scintillator material, its method of application and thickness, length of cell, cell material, type and configuration of reflectors, choice of photomultipliers, and factors affecting background. Response from various areas of the cell surface was studied with an alpha source and with radon filling. Coating the window with phosphor was found to be counter-productive. The optimum results obtained were with the inside of the cell (other than the window) covered with a thick layer of ZnS(Ag), or with a thick layer of reflective material coated with a thin layer of phosphor. With it, a 10 cm diameter plexiglass cell can be extended to at least 50 cm length without difficulty from insufficient pulse height.

  7. High-resolution hydrogen profiling in AlGaN/GaN heterostructures grown by different epitaxial methods

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Posada Flores, F; Redondo-Cubero, A; Bengoechea, A; Brana, A F; Munoz, E [Instituto de Sistemas Optoelectronicos y Microtecnologia (ISOM) and Dpto. IngenierIa Electronica (DIE), ETSI de Telecomunicacion, Universidad Politecnica de Madrid, E-28040 Madrid (Spain); Gago, R [Centro de Micro-Analisis de Materiales, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Jimenez, A [Dpto. Electronica, Escuela Politecnica Superior, Universidad de Alcala, E-28805 Alcala de Henares, Madrid (Spain); Grambole, D, E-mail: fposada@die.upm.e [Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, PF 51019, D-01314 Dresden (Germany)

    2009-03-07

    Hydrogen (H) incorporation into AlGaN/GaN heterostructures used in high electron mobility transistors, grown by different methods, is studied by high-resolution depth profiling. Samples grown on sapphire and Si(1 1 1) substrates by molecular-beam epitaxy and metal-organic vapour phase epitaxy; involving H-free and H-containing precursors, were analysed to evaluate the eventual incorporation of H into the wafer. The amount of H was measured by means of nuclear reaction analysis (NRA) using the {sup 1}H({sup 15}N,{alpha}{gamma}){sup 12}C reaction up to a depth of {approx}110 nm into the heterostructures. Interestingly, the H profiles are similar in all the samples analysed, with an increasing H content towards the surface and a negligible H incorporation into the GaN layer (0.24 {+-} 0.08 at%) or at the AlGaN/GaN interface. Therefore, NRA shows that H uptake is not related to the growth process or technique employed and that H contamination may be due to external sources after growth. The eventual correlation between topographical defects on the AlGaN surface and the H concentration are also discussed.

  8. A hydrogen ice cube

    NARCIS (Netherlands)

    Peters, C.J.; Schoonman, J.; Schrauwers, A.

    2004-01-01

    Hydrogen is considered to be a highly promising energy carrier. Nonetheless, before hydrogen can become the fuel of choice for the future a number of slight problems will have to be overcome. For example, how can hydrogen be safely stored? Motor vehicles running on hydrogen may be clean in concept

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. MICROSTRUCTURE AND MECHANICAL PROPERTY PERFORMANCE OF COMMERCIAL GRADE API PIPELINE STEELS IN HIGH PRESSURE GASEOUS HYDROGEN

    Energy Technology Data Exchange (ETDEWEB)

    Stalheim, Mr. Douglas [DGS Metallurgical Solutions Inc; Boggess, Todd [Secat; San Marchi, Chris [Sandia National Laboratories (SNL); Jansto, Steven [Reference Metals Company; Somerday, Dr. B [Sandia National Laboratories (SNL); Muralidharan, Govindarajan [ORNL; Sofronis, Prof. Petros [University of Illinois

    2010-01-01

    The continued growth of the world s developing countries has placed an ever increasing demand on traditional fossil fuel energy sources. This development has lead to increasing research and development of alternative energy sources. Hydrogen gas is one of the potential alternative energy sources under development. Currently the most economical method of transporting large quantities of hydrogen gas is through steel pipelines. It is well known that hydrogen embrittlement has the potential to degrade steel s mechanical properties when hydrogen migrates into the steel matrix. Consequently, the current pipeline infrastructure used in hydrogen transport is typically operated in a conservative fashion. This operational practice is not conducive to economical movement of significant volumes of hydrogen gas as an alternative to fossil fuels. The degradation of the mechanical properties of steels in hydrogen service is known to depend on the microstructure of the steel. Understanding the levels of mechanical property degradation of a given microstructure when exposed to hydrogen gas under pressure can be used to evaluate the suitability of the existing pipeline infrastructure for hydrogen service and guide alloy and microstructure design for new hydrogen pipeline infrastructure. To this end, the 2 Copyright 2010 by ASME microstructures of relevant steels and their mechanical properties in relevant gaseous hydrogen environments must be fully characterized to establish suitability for transporting hydrogen. A project to evaluate four commercially available pipeline steels alloy/microstructure performance in the presences of gaseous hydrogen has been funded by the US Department of Energy along with the private sector. The microstructures of four pipeline steels were characterized and then tensile testing was conducted in gaseous hydrogen and helium at pressures of 800, 1600 and 3000 psi. Based on measurements of reduction of area, two of the four steels that performed the best

  11. Editors' Choice Growth of Layered WS2Electrocatalysts for Highly Efficient Hydrogen Production Reaction

    KAUST Repository

    Alsabban, Merfat M.

    2016-08-18

    Seeking more economical alternative electrocatalysts without sacrificing much in performance to replace precious metal Pt is one of the major research topics in hydrogen evolution reactions (HER). Tungsten disulfide (WS2) has been recognized as a promising substitute for Pt owing to its high efficiency and low-cost. Since most existing works adopt solution-synthesized WS2 crystallites for HER, direct growth of WS2 layered materials on conducting substrates should offer new opportunities. The growth of WS2 by the thermolysis of ammonium tetrathiotungstate (NH4)(2)WS4 was examined under various gaseous environments. Structural analysis and electrochemical studies show that the H2S environment leads to the WS2 catalysts with superior HER performance with an extremely low overpotential (eta(10) = 184 mV). (C) The Author(s) 2016. Published by ECS. All rights reserved.

  12. Vortex combustor for low NOX emissions when burning lean premixed high hydrogen content fuel

    Science.gov (United States)

    Steele, Robert C; Edmonds, Ryan G; Williams, Joseph T; Baldwin, Stephen P

    2012-11-20

    A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.

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

    Science.gov (United States)

    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.

  14. The effect of dissolved hydrogen on the dissolution of {sup 233}U doped UO{sub 2}(s) high burn-up spent fuel and MOX fuel

    Energy Technology Data Exchange (ETDEWEB)

    Carbol, P. [Inst. for Transuranium Elements, Karlsruhe (Germany); Spahiu, K. (ed.) [and others

    2005-03-01

    In this report the results of the experimental work carried out in a large EU-research project (SFS, 2001-2004) on spent fuel stability in the presence of various amounts of near field hydrogen are presented. Studies of the dissolution of {sup 233}U doped UO{sub 2}(s) simulating 'old' spent fuel were carried out as static leaching tests, autoclave tests with various hydrogen concentrations and electrochemical tests. The results of the leaching behaviour of a high burn-up spent fuel pellet in 5 M NaCl solutions in the presence of 3.2 bar H{sub 2} pressure and of MOX fuel in dilute synthetic groundwater under 53 bar H{sub 2} pressure are also presented. In all the experimental studies carried out in this project, a considerable effect of hydrogen in the dissolution rates of radioactive materials was observed. The experimental results obtained in this project with a-doped UO{sub 2}, high burn-up spent fuel and MOX fuel together with literature data give a reliable background to use fractional alteration/dissolution rates for spent fuel of the order of 10{sup -6}/yr - 10{sup -8}/yr with a recommended value of 4x10{sup -7}/yr for dissolved hydrogen concentrations above 10{sup -3} M and Fe(II) concentrations typical for European repository concepts. Finally, based on a review of the experimental data and available literature data, potential mechanisms of the hydrogen effect are also discussed. The work reported in this document was performed as part of the Project SFS of the European Commission 5th Framework Programme under contract no FIKW-CT-2001-20192 SFS. It represents the deliverable D10 of the experimental work package 'Key experiments using a-doped UO{sub 2} and real spent fuel', coordinated by SKB with the participation of ITU, FZK-INE, ENRESA, CIEMAT, ARMINES-SUBATECH and SKB.

  15. Carboxylated polymers functionalized by cyclodextrins for the stabilization of highly efficient rhodium(0) nanoparticles in aqueous phase catalytic hydrogenation.

    Science.gov (United States)

    Noël, Sébastien; Léger, Bastien; Herbois, Rudy; Ponchel, Anne; Tilloy, Sébastien; Wenz, Gerhard; Monflier, Eric

    2012-11-21

    Rhodium(0) nanoparticles stabilized by a polymer containing carboxylate and β-cyclodextrin moieties have high stability and catalytic activity for aqueous hydrogenation reactions of olefins and aromatic substrates. This catalytic system can be recycled and reused without loss of activity. These high catalytic performances can be attributed to conjugated electrostatic interactions (carboxylate groups) and steric interactions (polymer structure and β-cyclodextrin moiety).

  16. Cobalt-doped graphitic carbon nitride photocatalysts with high activity for hydrogen evolution

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Pei-Wen; Li, Kui; Yu, Yu-Xiang; Zhang, Wei-De, E-mail: zhangwd@scut.edu.cn

    2017-01-15

    Graphical abstract: Cobalt-doped graphitic carbon nitride (Co−CN) was synthesized by one-step thermal polycondensation using cobalt phthalocyanine and melamine as precursors. The obtained photocatalysts display high and stable activity for photocatalytic generation of hydrogen through water splitting. - Highlights: • Cobalt-doped g-C{sub 3}N{sub 4} photocatalysts were prepared. • High and stable visible light photocatalytic activity for H{sub 2} evolution. • Efficient separation and transfer of photo-induced electron-hole pairs. - Abstract: Cobalt-doped graphitic carbon nitride (Co−CN) was synthesized by one-step thermal polycondensation using cobalt phthalocyanine (CoPc) and melamine as precursors. The π-π interaction between melamine and CoPc promotes cobalt doping into the framework of g-C{sub 3}N{sub 4}. The prepared samples were carefully characterized and the results demonstrated that Co-doped graphitic carbon nitride inhibited the crystal growth of graphitic carbon nitride (CN), leading to larger specific surface area (33.1 m{sup 2} g{sup −1}) and abundant Co-N{sub x} active sites, narrower band gap energy and more efficient separation of photogenerated electrons and holes. 0.46% Co−CN exhibited higher hydrogen evolution rate (28.0 μmol h{sup −1}) under visible light irradiation, which is about 3.0 times of that over the pure CN and about 2.2 times of that over cobalt-doped CN using CoCl{sub 2} ∙ 6H{sub 2}O as a cobalt source. This study provides a valuable strategy to modify CN with enhanced photocatalytic performance.

  17. Double quantum dots decorated 3D graphene flowers for highly efficient photoelectrocatalytic hydrogen production

    Science.gov (United States)

    Cheng, Qifa; Xu, Jing; Wang, Tao; Fan, Ling; Ma, Ruifang; Yu, Xinzhi; Zhu, Jian; Xu, Zhi; Lu, Bingan

    2017-11-01

    Photoelectrocatalysis (PEC) has been demonstrated as a promising technique for hydrogen production. However, the high over-potential and high recombination rate of photo-induced electron-hole pairs lead to poor hydrogen production efficiency. In order to overcome these problems, TiO2 and Au dual quantum dots (QDs) on three-dimensional graphene flowers (Au@TiO2@3DGFs) was synthesized by an electro-deposition strategy. The combination of Au and TiO2 modulates the band gap of TiO2, shifts the absorption to visible lights and improves the utilization efficiency of solar light. Simultaneously, the size-quantization TiO2 on 3DGFs not only achieves a larger specific surface area over conventional nanomaterials, but also promotes the separation of the photo-induced electron-hole pairs. Besides, the 3DGFs as a scaffold for QDs can provide more active sites and stable structure. Thus, the newly-developed Au@TiO2@3DGFs composite exhibited an impressive PEC activity and excellent durability. Under -240 mV potential (vs. RHE), the photoelectric current density involved visible light illumination (100 mW cm-2) reached 90 mA cm-2, which was about 3.6 times of the natural current density (without light, only 25 mA cm-2). It worth noting that the photoelectric current density did not degrade and even increased to 95 mA cm-2 over 90 h irradiation, indicating an amazing chemical stability.

  18. Monitoring and data acquisition of the high speed hydrogen pellet in SPINS

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Samiran Shanti, E-mail: samiran@ipr.res.in; Mishra, Jyotishankar; Gangradey, Ranjana; Dutta, Pramit; Rastogi, Naveen; Panchal, Paresh; Nayak, Pratik; Agarwal, Jyoti; Bairagi, Pawan; Patel, Haresh; Sharma, Hardik

    2016-11-15

    Highlights: • Pellet INjector System with monitoring and data acquisition is described. • A high speed camera was used to view pellet size, and its flight trajectory. • PXI based high speed control system is used data acquisition. • Pellets of length 2–4.8 mm and speed 250–750 m/s were obtained. - Abstract: Injection of solid hydrogen pellets is an efficient way of replenishing the spent fuel in high temperature plasmas. Aiming that, a Single Pellet INjector System (SPINS) is developed at Institute for Plasma Research (IPR), India, to initiate pellet injection related research in SST-1. The pellet injector is controlled by a PXI system based data acquisition and control (DAC) system for pellet formation, precise firing control, data collection and diagnostics. The velocity of high speed moving pellets is estimated by using two sets of light gate diagnostic. Apart from light gate, a fast framing camera is used to measure the pellet size and its speed. The pellet images are captured at a frame rate of ∼200,000 frames per second at (128 × 64) pixel resolution with an exposure time of 1 μs. Using these diagnostic, various cylindrical pellets of length ranging from 2 to 4.8 mm and speed 250–750 m/s were successfully obtained. This paper describes the control and data acquisition system of SPINS, the techniques for measurement of pellet velocity and capturing images of high speed moving pellet.

  19. High-Performance Near-Infrared Luminescent Solar Concentrators.

    Science.gov (United States)

    Rondão, Raquel; Frias, Ana R; Correia, Sandra F H; Fu, Lianshe; de Zea Bermudez, Verónica; André, Paulo S; Ferreira, Rute A S; Carlos, Luís D

    2017-04-12

    Luminescent solar concentrators (LSCs) appear as candidates to enhance the performance of photovoltaic (PV) cells and contribute to reduce the size of PV systems, decreasing, therefore, the amount of material needed and thus the cost associated with energy conversion. One way to maximize the device performance is to explore near-infrared (NIR)-emitting centers, resonant with the maximum optical response of the most common Si-based PV cells. Nevertheless, very few examples in the literature demonstrate the feasibility of fabricating LSCs emitting in the NIR region. In this work, NIR-emitting LSCs are reported using silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) (SiNc or NIR775) immobilized in an organic-inorganic tri-ureasil matrix (t-U(5000)). The photophysical properties of the SiNc dye incorporated into the tri-ureasil host closely resembled those of SiNc in tetrahydrofuran solution (an absolute emission quantum yield of ∼0.17 and a fluorescence lifetime of ∼3.6 ns). The LSC coupled to a Si-based PV device revealed an optical conversion efficiency of ∼1.5%, which is among the largest values known in the literature for NIR-emitting LSCs. The LSCs were posteriorly coupled to a Si-based commercial PV cell, and the synergy between the t-U(5000) and SiNc molecules enabled an effective increase in the external quantum efficiency of PV cells, exceeding 20% in the SiNc absorption region.

  20. High surface area polyaniline nanofiber synthesized in compressed CO{sub 2} and its application to a hydrogen sensor

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Quoc Minh; Kim, Sunwook [School of Chemical Engineering, University of Ulsan, Ulsan (Korea, Republic of)

    2016-01-15

    High surface area polyaniline (HSA PANI) nanofibers were synthesized through oxidative polymerization of aniline in compressed CO{sub 2} using cobalt chloride as an additive. SEM and TEM analyses showed that the HSA PANI nanofibers had a coarse surface of very thin nanofibers. The HSA PANI nanofibers had a fairly uniform diameter range of 70-90 nm with a length of 0.5-1 μm, and showed an electrical conductivity (EC) of 3.46 S/cm. TGA analysis revealed that the HSA PANI nanofibers had more doping substances than did ordinary PANI nanofibers. In the case of the HSA PANI nanofibers, direct measurement of the surface area using gas adsorption method showed high value of 68.4m{sup 2}/g, which was nearly twice that of ordinary PANI nanofibers. The HSA PANI nanofibers were used to fabricate the hydrogen sensor, exhibiting a large increase in resistance upon exposure to hydrogen gas. The hydrogen sensor in this work showed excellent characteristics, such as high sensitivity and short response time. The limit of detection (LOD) and limit of quantification (LOQ) of the hydrogen sensor were very low to show 40 ppm and 133 ppm of hydrogen, respectively.

  1. Molecular dynamics simulation of effect of hydrogen atoms on crack propagation behavior of α-Fe

    Energy Technology Data Exchange (ETDEWEB)

    Song, H.Y., E-mail: gsfshy@sohu.com; Zhang, L.; Xiao, M.X.

    2016-12-16

    The effect of the hydrogen concentration and hydrogen distribution on the mechanical properties of α-Fe with a pre-existing unilateral crack under tensile loading is investigated by molecular dynamics simulation. The results reveal that the models present good ductility when the front region of crack tip has high local hydrogen concentration. The peak stress of α-Fe decreases with increasing hydrogen concentration. The studies also indicate that for the samples with hydrogen atoms, the crack propagation behavior is independent of the model size and boundaries. In addition, the crack propagation behavior is significantly influenced by the distribution of hydrogen atoms. - Highlights: • The distribution of hydrogen plays a critical role in the crack propagation. • The peak stress decrease with the hydrogen concentration increasing. • The crack deformation behavior is disclosed and analyzed.

  2. Exergoeconomic optimization of coaxial tube evaporators for cooling of high pressure gaseous hydrogen during vehicle fuelling

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Rothuizen, Erasmus Damgaard; Markussen, Wiebke Brix

    2014-01-01

    Gaseous hydrogen as an automotive fuel is reaching the point of commercial introduction. Development of hydrogen fuelling stations considering an acceptable fuelling time by cooling the hydrogen to -40 C has started. This paper presents a design study of coaxial tube ammonia evaporators for three...... different concepts of hydrogen cooling, one onestage and two two-stage processes. An exergoeconomic optimization is imposed to all three concepts to minimize the total cost. A numerical heat transfer model is developed in Engineer Equation Solver, using heat transfer and pressure drop correlations from...

  3. Using a Potassium Acetate Solution for Cooling High Pressure Hydrogen in a Prototype Heat Exchanger

    DEFF Research Database (Denmark)

    Rothuizen, Erasmus Damgaard; Abel, M.; Rokni, Masoud

    2011-01-01

    A statement of intent assures more than 100.000 hydrogen vehicles will enter the market by 2015. A uniform approach for filling the vehicles has been developed and it states that cooling of the hydrogen is needed. For this purpose a test refrigeration facility was build. As the hydrogen...... was the most accurate of the methods compared. At low mass flows the calculated result was larger than the measured and at large mass flows the calculated results was lower than the measured. The used approach gives a reasonably accurate calculation for further investigations of cooling hydrogen....

  4. Fermentative hydrogen production in batch experiments using lactose, cheese whey and glucose: Influence of initial substrate concentration and pH

    Energy Technology Data Exchange (ETDEWEB)

    Davila-Vazquez, Gustavo; Alatriste-Mondragon, Felipe; Razo-Flores, Elias [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a seccion, C.P. 78216, San Luis Potosi, S.L.P (Mexico); de Leon-Rodriguez, Antonio [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a seccion, C.P. 78216, San Luis Potosi, S.L.P (Mexico)

    2008-10-15

    Biologically produced hydrogen using biomass and mixed bacterial cultures is one approach to generate renewable H{sub 2}. Response surface methodology (RSM) was used to study the effect of initial pH (3.88-8.12) and initial substrate concentration (0.86-29.14 g/L) on both hydrogen molar yield (HMY) and volumetric H{sub 2} production rate (VHPR). Lactose, cheese whey powder (CWP) and glucose were used as substrates and heat-treated anaerobic granular sludge as inoculum. For lactose, 3.6 mol H{sub 2}/mol lactose and 5.6 mmol H{sub 2}/L/h were found at pH 7.5 and 5 g lactose/L. CWP yielded 3.1 mol H{sub 2}/mol lactose at pH 6 and 15 g CWP/L while 8.1 mmol H{sub 2}/L/h were attained at pH 7.5 and 25 g CWP/L. Glucose yielded 1.46 mol H{sub 2}/mol substrate (pH 7.5, 5 g glucose/L), with a VHPR of 8.9 mmol H{sub 2}/L/h, at pH 8.12 and 15 g glucose/L. Acetic and butyric acids were the main organic metabolites detected. HMY and VHPR obtained in this study were found at initial pH above the reported optimum pH value for hydrogen production. These findings could be of significance when alkaline pretreatments are performed on organic feedstock by eliminating the need to lower the pH to acidic levels before fermentation start-up. (author)

  5. Catalyzed Nano-Framework Stablized High Density Reversible Hydrogen Storage Systems

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Xia [value too long for type character varying(50); Opalka, Susanne M.; Mosher, Daniel A; Laube, Bruce L; Brown, Ronald J; Vanderspurt, Thomas H; Arsenault, Sarah; Wu, Robert; Strickler, Jamie; Ronnebro, Ewa; Boyle, Tim; Cordaro, Joseph

    2010-06-30

    A wide range of high capacity on-board rechargeable material candidates have exhibited non-ideal behavior related to irreversible hydrogen discharge / recharge behavior, and kinetic instability or retardation. This project addresses these issues by incorporating solvated and other forms of complex metal hydrides, with an emphasis on borohydrides, into nano-scale frameworks of low density, high surface area skeleton materials to stabilize, catalyze, and control desorption product formation associated with such complex metal hydrides. A variety of framework chemistries and hydride / framework combinations were investigated to make a relatively broad assessment of the method's potential. In this project, the hydride / framework interactions were tuned to decrease desorption temperatures for highly stable compounds or increase desorption temperatures for unstable high capacity compounds, and to influence desorption product formation for improved reversibility. First principle modeling was used to explore heterogeneous catalysis of hydride reversibility by modeling H2 dissociation, hydrogen migration, and rehydrogenation. Atomic modeling also demonstrated enhanced NaTi(BH4)4 stabilization at nano-framework surfaces modified with multi-functional agents. Amine multi-functional agents were found to have more balanced interactions with nano-framework and hydride clusters than other functional groups investigated. Experimentation demonstrated that incorporation of Ca(BH4)2 and Mg(BH4)2 in aerogels enhanced hydride desorption kinetics. Carbon aerogels were identified as the most suitable nano-frameworks for hydride kinetic enhancement and high hydride loading. High loading of NaTi(BH4)4 ligand complex in SiO2 aerogel was achieved and hydride stability was improved with the aerogel. Although improvements of desorption kinetics was observed, the incorporation of

  6. Hydrogen induced cracking tests of high strength steels and nickel-iron base alloys using the bolt-loaded specimen

    Energy Technology Data Exchange (ETDEWEB)

    Vigilante, G.N.; Underwood, J.H.; Crayon, D.; Tauscher, S.; Sage, T.; Troiano, E. [Army Armament RD and E Center, Watervliet, NY (United States). Benet Labs.

    1997-12-31

    Hydrogen induced cracking tests were conducted on high strength steels and nickel-iron base alloys using the constant displacement bolt-loaded compact specimen. The bolt-loaded specimen was subjected to both acid and electrochemical cell environments in order to produce hydrogen. The materials tested were A723, Maraging 200, PH 13-8 Mo, Alloy 718, Alloy 706, and A286, and ranged in yield strength from 760--1400 MPa. The effects of chemical composition, refinement, heat treatment, and strength on hydrogen induced crack growth rates and thresholds were examined. In general, all high strength steels tested exhibited similar crack growth rates and thresholds were examined. In general, all high strength steels tested exhibited similar crack growth rates and threshold levels. In comparison, the nickel-iron base alloys tested exhibited up to three orders of magnitude lower crack growth rates than the high strength steels tested. It is widely known that high strength steels and nickel base alloys exhibit different crack growth rates, in part, because of their different crystal cell structure. In the high strength steels tested, refinement and heat treatment had some effect on hydrogen induced cracking, though strength was the predominant factor influencing susceptibility to cracking. When the yield strength of one of the high strength steels tested was increased moderately, from 1130 MPa to 1275 MPa, the incubation times decreased by over two orders of magnitude, the crack growth rates increased by an order of magnitude, and the threshold stress intensity was slightly lower.

  7. High plasma uric acid concentration: causes and consequences

    Directory of Open Access Journals (Sweden)

    de Oliveira Erick

    2012-04-01

    Full Text Available Abstract High plasma uric acid (UA is a precipitating factor for gout and renal calculi as well as a strong risk factor for Metabolic Syndrome and cardiovascular disease. The main causes for higher plasma UA are either lower excretion, higher synthesis or both. Higher waist circumference and the BMI are associated with higher insulin resistance and leptin production, and both reduce uric acid excretion. The synthesis of fatty acids (tryglicerides in the liver is associated with the de novo synthesis of purine, accelerating UA production. The role played by diet on hyperuricemia has not yet been fully clarified, but high intake of fructose-rich industrialized food and high alcohol intake (particularly beer seem to influence uricemia. It is not known whether UA would be a causal factor or an antioxidant protective response. Most authors do not consider the UA as a risk factor, but presenting antioxidant function. UA contributes to > 50% of the antioxidant capacity of the blood. There is still no consensus if UA is a protective or a risk factor, however, it seems that acute elevation is a protective factor, whereas chronic elevation a risk for disease.

  8. Design requirements for high-efficiency high concentration ratio space solar cells

    Science.gov (United States)

    Rauschenbach, H.; Patterson, R.

    1980-01-01

    A miniaturized Cassegrainian concentrator system concept was developed for low cost, multikilowatt space solar arrays. The system imposes some requirements on solar cells which are new and different from those imposed for conventional applications. The solar cells require a circular active area of approximately 4 mm in diameter. High reliability contacts are required on both front and back surfaces. The back area must be metallurgically bonded to a heat sink. The cell should be designed to achieve the highest practical efficiency at 100 AMO suns and at 80 C. The cell design must minimize losses due to nonuniform illumination intensity and nonnormal light incidence. The primary radiation concern is the omnidirectional proton environment.

  9. The thermodynamic properties of the high-pressure superconducting state in the hydrogen-rich compounds

    Science.gov (United States)

    Szcz&şacute; niak, Radosław; Durajski, Artur P.

    2013-11-01

    The ab initio calculations suggest that the superconducting state in CaH6 under the pressure (p) at 150 GPa has the highest critical temperature among the examined hydrogen-rich compounds. For this reason, the relevant thermodynamic parameters of the superconducting state in CaH6 have been determined; a wide range of the Coulomb pseudopotential has been assumed: μ⋆∈. It has been found that: (i) The critical temperature (TC) changes in the range from 243 K to 180 K (ii) The values of the ratio of the energy gap to the critical temperature (RΔ ≡ 2Δ(0)/kBTC) can be found in the range from 5.42 to 5.02. (iii) The ratio of the specific heat jump (ΔC(TC)) to the value of the specific heat in the normal state (CN(TC)), which has been represented by the symbol RC, takes the values from 3.30 to 3.18. (iv) The ratio R≡TC(T)/HC2(0), where HC(0) denotes the critical thermodynamic field, changes from 0.122 to 0.125. The above results mean that even for the strong electron depairing correlations the superconducting state in CaH6 is characterized by a very high value of TC, and the remaining thermodynamic parameters significantly deviate from the predictions of the BCS theory. The study has brought out the expressions that correctly predict the values of the thermodynamic parameters for the superconducting state in CaH6 and for the compounds: SiH4(H2)2, Si2H6, B2H6, SiH4, GeH4, and PtH. Next, in the whole family of the hydrogen-rich compounds, the possible ranges of the values have been determined for TC, RΔ, RC, and RH. It has been found that the maximum value of the critical temperature can be equal to 764 K, which very well correlates with TC for metallic hydrogen (p = 2 TPa). Other parameters (RΔ, RC, and RH) should not deviate from the predictions of the BCS theory more than the analogous parameters for CaH6.

  10. Advanced gasifier and water gas shift technologies for low cost coal conversion to high hydrogen syngas

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Andrew Kramer [Gas Technology Inst., Des Plaines, IL (United States)

    2016-09-30

    The Gas Technology Institute (GTI) and team members RTI International (RTI), Coanda Research and Development, and Nexant, are developing and maturing a portfolio of technologies to meet the United States Department of Energy (DOE) goals for lowering the cost of producing high hydrogen syngas from coal for use in carbon capture power and coal-to-liquids/chemicals. This project matured an advanced pilot-scale gasifier, with scalable and commercially traceable components, to readiness for use in a first-of-a-kind commercially-relevant demonstration plant on the scale of 500-1,000 tons per day (TPD). This was accomplished through cold flow simulation of the gasifier quench zone transition region at Coanda and through an extensive hotfire gasifier test program on highly reactive coal and high ash/high ash fusion temperature coals at GTI. RTI matured an advanced water gas shift process and catalyst to readiness for testing at pilot plant scale through catalyst development and testing, and development of a preliminary design basis for a pilot scale reactor demonstrating the catalyst. A techno-economic analysis was performed by Nexant to assess the potential benefits of the gasifier and catalyst technologies in the context of power production and methanol production. This analysis showed an 18%reduction in cost of power and a 19%reduction in cost of methanol relative to DOE reference baseline cases.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ciccarelli, G.; Boccio, J.L.; Ginsberg, T.; Finfrock, C. [Brookhaven National Lab., Upton, NY (United States)] [and others

    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.

  12. Protein aggregation under high concentration/density state during chromatographic and ultrafiltration processes.

    Science.gov (United States)

    Arakawa, Tsutomu; Ejima, Daisuke; Akuta, Teruo

    2017-02-01

    Local transient high protein concentration or high density condition can occur during processing of protein solutions. Typical examples are saturated binding of proteins during column chromatography and high protein concentration on the semi-permeable membrane during ultrafiltration. Both column chromatography and ultrafiltration are fundamental technologies, specially for production of pharmaceutical proteins. We summarize here our experiences related to such high concentration conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Influence of carbohydrates and proteins concentration on fermentative hydrogen production using canteen based waste under acidophilic microenvironment.

    Science.gov (United States)

    Reddy, M Venkateswar; Chandrasekhar, K; Mohan, S Venkata

    2011-10-10

    Functional role of biomolecules viz., carbohydrates and proteins on acidogenic biohydrogen (H(2)) production was studied through the treatment of canteen based composite food waste. The performance was evaluated in an anaerobic sequencing batch reactor (AnSBR) at pH 6 with five variable organic loading conditions (OLR1, 0.854; OLR2, 1.69; OLR3, 3.38; OLR4, 6.54 and OLR5, 9.85kgCOD/m(3)-day). Experimental data depicted the feasibility of H(2) production from the stabilization of food waste and was found to depend on the substrate load. Among the five loading conditions studied, OLR4 documented maximum H(2) production (69.95mmol), while higher substrate degradation (3.99kgCOD/m(3)-day) was observed with OLR5. Specific hydrogen yield (SHY) vary with the removal of different biomolecules and was found to decrease with increase in the OLR. Maximum SHY was observed with hexose removal at OLR1 (139.24mol/kg Hexose(R) at 24h), followed by pentoses (OLR1, 108.26mol/kg Pentose(R) at 48h), proteins (OLR1, 109.71mol/kg Protein(R) at 48h) and total carbohydrates (OLR1, 58.31mol/kg CHO(R) at 24h). Prot