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Sample records for hydrogen mixture implications

  1. Detonation of hydrogen-air mixtures

    International Nuclear Information System (INIS)

    Lee, J.H.S.; Knystautas, R.; Benedick, W.B.

    1983-01-01

    The detonation of a hydrogen-air cloud subsequent to an accidental release of hydrogen into ambient surroundings cannot be totally ruled out in view of the relative sensitivity of the hydrogen-air system. The present paper investigates the key parameters involved in hydrogen-air detonations and attempts to establish quantitative correlations between those that have important practical implications. Thus, for example, the characteristic length scale lambda describing the cellular structure of a detonation front is measured for a broad range of hydrogen-air mixtures and is quantitatively correlated with the key dynamic detonation properties such as detonability, transmission and initiation

  2. Industrial implications of hydrogen

    International Nuclear Information System (INIS)

    Pressouyre, G.M.

    1982-01-01

    Two major industrial implications of hydrogen are examined: problems related to the effect of hydrogen on materials properties (hydrogen embrittlement), and problems related to the use and production of hydrogen as a future energy vector [fr

  3. Method of removing hydrogen sulphide from hot gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Furimsky, E.; Yumura, M.

    1987-12-22

    Hydrogen sulphide can be removed from hot gas mixtures by contacting the hot gas mixture at temperatures in the range of 500-900/sup 0/C with an adsorbent consisting of managanese nodules. The nodules may contain additional calcium cations. In sulphided form, the nodules are catalytically active for hydrogen sulphide decomposition to produce hydrogen. Regeneration of the adsorbent can be accomplished by roasting in an oxidizing atmosphere. The nodules can be used to treat gaseous mixtures containing up to 20% hydrogen sulfide, for example, gases produced during pyrolysis, cracking, coking, and hydrotreating processes. Experiments using the processes described in this patent are also outlined. 6 tabs.

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

    Science.gov (United States)

    Shaw, H.R.

    1963-01-01

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

  5. Kinetics of the excited muonic hydrogen in the mixtures of hydrogen isotopes in helium

    International Nuclear Information System (INIS)

    Bystritskij, V.M.; Kravtsov, A.V.; Popov, N.P.

    1989-01-01

    De-excitation of the excited muonic hydrogen in the mixture of hydrogen isotopes and helium is considered. The method is proposed which allows one to determine the rates of the muon transfer from the excited muonic hydrogen to helium nuclei, as well as the probability of the direct muon atomic capture by nuclei of hydrogen isotopes. 20 refs.; 4 figs

  6. Gas-chromatographic separation of hydrogen isotopic mixtures

    International Nuclear Information System (INIS)

    Preda, Anisoara; Bidica, Nicolae

    2005-01-01

    Full text: Gas chromatographic separation of hydrogen isotopes have been reported in the literature since late of 1950's. Gas chromatography is primarily an analytical method, but because of its properties it may be used in many other fields with excellent results. A simple method is proposed for the gas-chromatographic analysis of complex gas mixtures containing hydrogen isotopes; the method is based on the substantial difference in the thermal conductivity of these isotopes. One of the main disadvantages of the conventional gas chromatography is the long retention times required for the analysis of hydrogen gas mixtures while the column is operated at very low temperature. The method described in this paper was based on using a capillary molecular sieve 5A column operated for this kind of separation at 173 K. The carrier gas was Ne and the detector was TCD. In the paper chromatograms for various carrier flow rates and various hydrogen isotope mixtures are presented. (authors)

  7. Isotope mixtures of hydrogen in vanadium

    International Nuclear Information System (INIS)

    Mecking-Schloetensack, P.

    1982-03-01

    The properties of isotope-mixtures of Protium and Deuterium stored in Vanadium have been studied. Protium and Deuterium are existing as interstitial-atoms on tetrahedral sites as well as on octahedral sites in this system. This feature leads to large isotopic-effects between the two isotopes. The dependence of the thermodynamic functions like heat of solution, nonconfigurational entropy, specific heat and ordering temperatures from the composition of the isotope-mixture has been determined. (orig.)

  8. Quantitative mass-spectrometric analysis of hydrogen helium isotope mixtures

    International Nuclear Information System (INIS)

    Langer, U.

    1998-12-01

    This work deals with the mass-spectrometric method for the quantitative analysis of hydrogen-helium-isotope mixtures, with special attention to fusion plasma diagnostics. The aim was to use the low-resolution mass spectrometry, a standard measuring method which is well established in science and industry. This task is solved by means of the vector mass spectrometry, where a mass spectrum is repeatedly measured, but with stepwise variation of the parameter settings of a quadruple mass spectrometer. In this way, interfering mass spectra can be decomposed and, moreover, it is possible to analyze underestimated mass spectra of complex hydrogen-helium-isotope mixtures. In this work experimental investigations are presented which show that there are different parameters which are suitable for the UMS-method. With an optimal choice of the parameter settings hydrogen-helium-isotope mixtures can be analyzed with an accuracy of 1-3 %. In practice, a low sensitivity for small helium concentration has to be noted. To cope with this task, a method for selective hydrogen pressure reduction has been developed. Experimental investigations and calculations show that small helium amounts (about 1 %) in a hydrogen atmosphere can be analyzed with an accuracy of 3 - 10 %. Finally, this work deals with the effects of the measuring and calibration error on the resulting error in spectrum decomposition. This aspect has been investigated both in general mass-spectrometric gas analysis and in the analysis of hydrogen-helium-mixtures by means of the vector mass spectrometry. (author)

  9. Isotope exchange reactions in hydrogen mixtures

    International Nuclear Information System (INIS)

    Czaplinski, W.; Gula, A.; Kravtsov, A.; Mikhailov, A.; Popov, N.

    1990-12-01

    The rates of isotopic exchange for the excited states of muonic hydrogen are calculated as functions of collision energy. Ground state population q 1s for different collision energies, target densities and isotope concentrations is obtained. It is shown that for principal quantum numbers n > 5 the isotopic exchange still considerably influences the value of q 1s . (author)

  10. Gas--liquid equilibria in mixtures of hydrogen and thianaphthene

    Energy Technology Data Exchange (ETDEWEB)

    Sebastian, H M; Simnick, J J; Lin, H M; Chao, K C

    1978-12-01

    Gas--liquid equilibrium conditions in binary mixtures of hydrogen and thianaphthene were experimentally determined at temperature of 190 to 430/sup 0/C and pressures to 250 atm in a flow apparatus. The same apparatus was also employed to measure the vapor pressure of thianaphthene. Comparisons of the new mixture data with Chao--Seader and Grayson--Streed correlations show that both correlations predict the thianaphthene equilibrium ratios well but are in error by up to about 45 and 35% respectively for K-values of hydrogen. 4 figures, 2 tables.

  11. Determination of peracetic acid and hydrogen peroxide in the mixture

    OpenAIRE

    Bodiroga Milanka; Ognjanović Jasminka

    2002-01-01

    Iodometric and permanganometric titrations were used for determination of peracetic acid and hydrogen peroxide (H2O2) in the mixture. Two procedures were described and compared. Titrations could be done in only one vessel, in the same reaction mixture, when iodometric titration of peracetic acid was continued after the permanganometric titration of H2O2, (procedure A). Peracetic acid and H2O2, as oxidizing agents, reacted with potassium iodide in an acid medium, evolving iodine. This reaction...

  12. Microstructure and hydrogen bonding in water-acetonitrile mixtures.

    Science.gov (United States)

    Mountain, Raymond D

    2010-12-16

    The connection of hydrogen bonding between water and acetonitrile in determining the microheterogeneity of the liquid mixture is examined using NPT molecular dynamics simulations. Mixtures for six, rigid, three-site models for acetonitrile and one water model (SPC/E) were simulated to determine the amount of water-acetonitrile hydrogen bonding. Only one of the six acetonitrile models (TraPPE-UA) was able to reproduce both the liquid density and the experimental estimates of hydrogen bonding derived from Raman scattering of the CN stretch band or from NMR quadrupole relaxation measurements. A simple modification of the acetonitrile model parameters for the models that provided poor estimates produced hydrogen-bonding results consistent with experiments for two of the models. Of these, only one of the modified models also accurately determined the density of the mixtures. The self-diffusion coefficient of liquid acetonitrile provided a final winnowing of the modified model and the successful, unmodified model. The unmodified model is provisionally recommended for simulations of water-acetonitrile mixtures.

  13. Determination of hydrogen sulphide and sulphur dioxide in a mixture

    International Nuclear Information System (INIS)

    Narayanan, S.S.; Rao, V.R.S.

    1989-01-01

    A method is proposed for the determination of hydrogen sulfide and sulfur dioxide in a mixture. The method is based on the quantitative oxidation of sulfide and sulfite with an excess of radiochloramine-T in alkaline medium (0.1N NaOH). The released chloride activity is proportional to the total amount of sulfide and sulfite present. Addition of 1% CdSO 4 solution to the mixture of sulfide and sulfite precipitates sulfide and sulfite in the filtrate determined by the reagent. From the difference in activities, the amount of sulfide can be calculated. This method can be employed for the determination of hydrogen sulfide and sulfur dioxide in air samples. (author) 11 refs.; 3 tabs

  14. Internal combustion engines fueled by natural gas-hydrogen mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Akansu, S.O.; Kahraman, N. [Erciyes University, Kayseri (Turkey). Engineering Faculty; Dulger, Z. [Kocaeli University (Turkey). Engineering Faculty; Veziroglu, T.N. [University of Miami, Coral Gables, FL (United States). College of Engineering

    2004-11-01

    In this study, a survey of research papers on utilization of natural gas-hydrogen mixtures in internal combustion engines is carried out. In general, HC, CO{sub 2}, and CO emissions decrease with increasing H{sub 2}, but NO{sub x} emissions generally increase. If a catalytic converter is used, NO{sub x} emission values can be decreased to extremely low levels. Consequently, equivalence zero emission vehicles (EZEV) standards may be reached. Efficiency values vary with H{sub 2} amount, spark timing, compression ratio, equivalence ratio, etc. Under certain conditions, efficiency values can be increased. In terms of BSFC, emissions and BTE, a mixture of low hydrogen percentage is suitable for using. (author)

  15. Turbulent burning rates of methane and methane-hydrogen mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Fairweather, M. [School of Process, Environmental and Materials Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Ormsby, M.P.; Sheppard, C.G.W. [School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Woolley, R. [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2009-04-15

    Methane and methane-hydrogen (10%, 20% and 50% hydrogen by volume) mixtures have been ignited in a fan stirred bomb in turbulence and filmed using high speed cine schlieren imaging. Measurements were performed at 0.1 MPa (absolute) and 360 K. A turbulent burning velocity was determined for a range of turbulence velocities and equivalence ratios. Experimental laminar burning velocities and Markstein numbers were also derived. For all fuels the turbulent burning velocity increased with turbulence velocity. The addition of hydrogen generally resulted in increased turbulent and laminar burning velocity and decreased Markstein number. Those flames that were less sensitive to stretch (lower Markstein number) burned faster under turbulent conditions, especially as the turbulence levels were increased, compared to stretch-sensitive (high Markstein number) flames. (author)

  16. Water fog inerting of hydrogen-air mixtures

    International Nuclear Information System (INIS)

    Zalosh, R.G.; Bajpai, S.N.

    1982-01-01

    Laboratory tests have been conducted to determine the effects of water fog density, droplet diameter and temperature on the lower flammable limit (LFL) of hydrogen-air-steam mixtures. Five different fog nozzles were used to generate dense fogs with volume mean drop diameters ranging from 20 micro-meters to 115 micro-meters. At 20 0 C, these nozzles marginally raised the hydrogen LFL from 4.0 vol.% hydrogen to typically 4.8%, with one exceptional nozzle producing an LFL of 7.2%. At 50 0 C, the LFL in the presence of dense fog ranged from 5.0 to 7.9%, while at 70 0 C, the range was 5.9 to 8.5%. Fog densities required to achieve a given level of partial inerting increased with approximately the second power of average drop diameter, as predicted by a theoretical flame quenching analysis

  17. 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.

  18. ELECTROCHEMICAL SEPARATION AND CONCENTRATION OF HYDROGEN SULFIDE FROM GAS MIXTURES

    Science.gov (United States)

    Winnick, Jack; Sather, Norman F.; Huang, Hann S.

    1984-10-30

    A method of removing sulfur oxides of H.sub.2 S from high temperature gas mixtures (150.degree.-1000.degree. C.) is the subject of the present invention. An electrochemical cell is employed. The cell is provided with inert electrodes and an electrolyte which will provide anions compatible with the sulfur containing anions formed at the anode. The electrolyte is also selected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the sulfur gases are converted to SO.sub.4 -- or, in the case of H.sub.2 S, to S--. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels (>10X). Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

  19. Fog inerting criteria for hydrogen/air mixtures

    International Nuclear Information System (INIS)

    Tsai, S.S.; Liparulo, N.J.

    1982-01-01

    A distributed ignition system has been proposed to ignite hydrogen at low concentration in the ice condenser containment during severe accidents. The post-accident containment atmosphere could be misty due to fog generation from the break flow and condensation in the ice bed. Thus it is important to establish a fog inerting criterion for effective performance of the ignition system. This paper presents such a criterion that specifies the necessary fogging conditions, i.e., fog concentration and drop size, for inerting a hydrogen/air mixture. The criterion shows that the minimum fog inerting concentration varies with the square of the volume mean fog drop size. The present fog inerting criterion is shown to be in general agreement with the Factory Mutual test data

  20. Hydrogenic ionization model for mixtures in non-LTE plasmas

    International Nuclear Information System (INIS)

    Djaoui, A.

    1999-01-01

    The Hydrogenic Ionization Model for Mixtures (HIMM) is a non-Local Thermodynamic Equilibrium (non-LTE), time-dependent ionization model for laser-produced plasmas containing mixtures of elements (species). In this version, both collisional and radiative rates are taken into account. An ionization distribution for each species which is consistent with the ambient electron density is obtained by use of an iterative procedure in a single calculation for all species. Energy levels for each shell having a given principal quantum number and for each ion stage of each species in the mixture are calculated using screening constants. Steady-state non-LTE as well as LTE solutions are also provided. The non-LTE rate equations converge to the LTE solution at sufficiently high densities or as the radiation temperature approaches the electron temperature. The model is particularly useful at low temperatures where convergence problems are usually encountered in our previous models. We apply our model to typical situation in x-ray laser research, laser-produced plasmas and inertial confinement fusion. Our results compare well with previously published results for a selenium plasma. (author)

  1. Autoignited laminar lifted flames of methane/hydrogen mixtures in heated coflow air

    KAUST Repository

    Choi, Byungchul; Chung, Suk-Ho

    2012-01-01

    Autoignited lifted flame behavior in laminar jets of methane/hydrogen mixture fuels has been investigated experimentally in heated coflow air. Three regimes of autoignited lifted flames were identified depending on initial temperature and hydrogen

  2. Isotopic analysis of H2, HD, D2 mixtures and analysis of ortho-para-hydrogen mixtures by gas chromatography

    International Nuclear Information System (INIS)

    Botter, F.; Perriere, G. de la; Tistchenko, S.

    1961-01-01

    This communication describes the present situation concerning the possibilities of vapor phase chromatography for the separation and analysis of mixtures of H 2 , HD and D 2 and of ortho- and para-hydrogen mixtures. Separation factors for physical adsorption of the various varieties of hydrogen have been deduced from chromatograms and have also been measured directly with a static method - the agreements is good. (author) [fr

  3. NO{sub x} emissions from combustion of hydrogen mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Roertveit, Geir Johan

    2002-07-01

    This work includes five different parts each of which has resulted in a paper that is accepted and submitted for publication. Additionally, a short introductory background section precedes these papers. A significant amount of experimental data is presented for the combustion of hydrogen which focus on emission of NO{sub x}. Different dilutes were added to the hydrogen to reduce the flame temperature and subsequently the NO{sub x} emissions. These experiments were performed in a counterflow burner where a flat steady flame layer facilitated accurate measurements. The experiments were compared with numerical calculations to assist the interpretation and discussion of the results. It was found that the experimental results compared well with numerical calculations of NO{sub x} at temperatures of up to 1900 K, while for higher temperatures an increasing discrepancy was found due to the influence of the sampling equipment. Nitrogen diluted methane was enriched by hydrogen from 0to 100 % to study the effect of NO{sub x} with the use of different fuel mixtures in the same counterflow burner. For a similar temperature of the NO{sub x} emitted from a H{sub 2} flame is only 25 % of that of a methane flame. Experiments compared to the pure methane flame showed that there is only a reduction of NO{sub x} when there is very high hydrogen content in the fuel mixture and for most mixtures an actual increase in NO{sub x} is observed. This is found partly due to a triggering of the NO{sub x} from the prompt mechanism. Natural gas and methane have both been substituted by up to 30 % H{sub 2} at constant load in various burners to reveal the effect of H{sub 2} enrichment on emissions. The burners include a swirl burner, a fibre burner, a porous burner and a catalytically supported porous burner. The thermal loads were varied from 2.6 to 21 kW, while excess air ratios were varied form 1 to 1.8. In general little effect of H{sub 2} is found by enriching the fuel. At temperatures of up

  4. Determination of peracetic acid and hydrogen peroxide in the mixture

    Directory of Open Access Journals (Sweden)

    Bodiroga Milanka

    2002-01-01

    Full Text Available Iodometric and permanganometric titrations were used for determination of peracetic acid and hydrogen peroxide (H2O2 in the mixture. Two procedures were described and compared. Titrations could be done in only one vessel, in the same reaction mixture, when iodometric titration of peracetic acid was continued after the permanganometric titration of H2O2, (procedure A. Peracetic acid and H2O2, as oxidizing agents, reacted with potassium iodide in an acid medium, evolving iodine. This reaction was used for the quantitative iodometric determination of total peroxide in procedure B. H2O2 reacted with potassium permanganate in acid medium, but peracetic acid did not react under the same conditions. That made possible the selective permanganometric determination of H2O2 in the presence of peracetic acid. The procedure B was performed in two titration vessels (KV=3.4% for peracetic acid, 0.6% for H2O2. The procedure A for iodometric determination of peracetic acid in one titration vessel after permanganometric titration of H2O2 was recommended (KV=2,5% for peracetic acid, 0,45% for H2O2.

  5. An electrochemical hydrogen meter for measuring hydrogen in sodium using a ternary electrolyte mixture

    CERN Document Server

    Sridharan, R; Nagaraj, S; Gnanasekaran, T; Periaswami, G

    2003-01-01

    An electrochemical sensor for measuring hydrogen concentration in liquid sodium that is based on a ternary mixture of LiCl, CaCl sub 2 and CaHCl as the electrolyte has been developed. DSC experiments showed the eutectic temperature of this ternary system to be approx 725 K. Impedance spectroscopic analysis of the electrolyte indicated ionic conduction through a molten phase at approx 725 K. Two electrochemical hydrogen sensors were constructed using the ternary electrolyte of composition 70 mol% LiCl:16 mol% CaHCl:14 mol% CaCl sub 2 and tested at 723 K in a mini sodium loop and at hydrogen levels of 60-250 ppb in sodium. The sensors show linear response in this concentration range and are capable of detecting a change of 10 ppb hydrogen in sodium over a background level of 60 ppb. Identification of this electrolyte system and its use in a sensor for measuring hydrogen in sodium are described in this paper.

  6. Purification of free hydrogen or hydrogen combined in a gaseous mixture by chemical reactions with uranium

    International Nuclear Information System (INIS)

    Caron-Charles, M.; Gilot, B.

    1989-01-01

    Within the framework of the European fusion program, the authors are dealing with the tritium technology aspect. Hydrogen, free or under a combined form within a H 2 , N 2 , NH 3 , O 2 , gaseous mixture, can be purified by chemical reactions with uranium metal. The resulting reactions consist in absorbing the impurities without holding back H 2 . Working conditions have been defined according to two main goals: the formation of stable solid products, especially under hydrogenated atmosphere and the optimization of the material quantities to be used. Thermodynamical considerations have shown that the 950-1300 K temperature range should be suitable for this chemical process. Experiments performed with massive uranium set in a closed reactor at 973 K, have produced hydrogen according to the predicted reactions rates. But they have also pointed out the importance of interferences that might occur in the uranium-gas system, on the gases conversion rates. The comparison between the chemical kinetic ratings of the reactions of pure gases and the chemical kinetic ratings of the reactions of the same gases in mixture, has been set up. It proves that simultaneous reactions can modify the working conditions of the solid products formation, and particularly modify their structure. In this case, chemical kinetic ratings are increased up to their maximal value; that means surface phenomena are favoured as with uranium powder gases reactions. (orig.)

  7. Combustion characteristics of nanoaluminum, liquid water, and hydrogen peroxide mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Sabourin, J.L.; Yetter, R.A. [The Pennsylvania State University, Department of Mechanical and Nuclear Engineering, University Park, PA 16801 (United States); Risha, G.A. [The Pennsylvania State University, Division of Business and Engineering, Altoona, PA 16601 (United States); Son, S.F. [Purdue University, School of Mechanical Engineering, West Lafayette, IN 47907 (United States); Tappan, B.C. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2008-08-15

    An experimental investigation of the combustion characteristics of nanoaluminum (nAl), liquid water (H{sub 2}O{sub (l)}), and hydrogen peroxide (H{sub 2}O{sub 2}) mixtures has been conducted. Linear and mass-burning rates as functions of pressure, equivalence ratio ({phi}), and concentration of H{sub 2}O{sub 2} in H{sub 2}O{sub (l)} oxidizing solution are reported. Steady-state burning rates were obtained at room temperature using a windowed pressure vessel over an initial pressure range of 0.24 to 12.4 MPa in argon, using average nAl particle diameters of 38 nm, {phi} from 0.5 to 1.3, and H{sub 2}O{sub 2} concentrations between 0 and 32% by mass. At a nominal pressure of 3.65 MPa, under stoichiometric conditions, mass-burning rates per unit area ranged between 6.93 g/cm{sup 2} s (0% H{sub 2}O{sub 2}) and 37.04 g/cm{sup 2} s (32% H{sub 2}O{sub 2}), which corresponded to linear burning rates of 9.58 and 58.2 cm/s, respectively. Burning rate pressure exponents of 0.44 and 0.38 were found for stoichiometric mixtures at room temperature containing 10 and 25% H{sub 2}O{sub 2}, respectively, up to 5 MPa. Burning rates are reduced above {proportional_to}5 MPa due to the pressurization of interstitial spaces of the packed reactant mixture with argon gas, diluting the fuel and oxidizer mixture. Mass burning rates were not measured above {proportional_to}32% H{sub 2}O{sub 2} due to an anomalous burning phenomena, which caused overpressurization within the quartz sample holder, leading to tube rupture. High-speed imaging displayed fingering or jetting ahead of the normal flame front. Localized pressure measurements were taken along the sample length, determining that the combustion process proceeded as a normal deflagration prior to tube rupture, without significant pressure buildup within the tube. In addition to burning rates, chemical efficiencies of the combustion reaction were determined to be within approximately 10% of the theoretical maximum under all conditions

  8. Phenomenology of deflagration and detonation of hydrogen-air mixtures in water cooled nuclear power plants

    International Nuclear Information System (INIS)

    Lombardi, G.

    1984-01-01

    This paper summarizes fundamentals of the flammability of the hydrogen-air mixtures and hydrogen-air containing added steam or other inerting agent. The flammability behaviour of such gaseous mixtures is described with reference to physical and chemical conditions close enough to those expected in the containment of a nuclear reactor during a LOCA

  9. Detonation cell size measurements and predictions in hydrogen-air-steam mixtures at elevated temperatures

    International Nuclear Information System (INIS)

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

    1994-01-01

    The present research reports on the effect of initial mixture temperature on the experimentally measured detonation cell size for hydrogen-air-steam mixtures. Experimental and theoretical research related to combustion phenomena in hydrogen-air-steam mixtures has been ongoing for many years. However, detonation cell size data currently exists or hydrogen-air-steam mixtures up to a temperature of only 400K. Sever accident scenarios have been identified for light water reactors (LWRs) where hydrogen-air mixture temperatures in excess of 400K could be generated within containment. The experiments in this report focus on extending the cell size data base for initial mixture temperatures in excess of 400K. The experiments were carried out in a 10-cm inner-diameter, 6.1-m long heated detonation tube with a maximum operating temperature of 700K and spatial temperature uniformity of ±14K. Detonation cell size measurements provide clear evidence that the effect of hydrogen-air initial 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 test vessel, based upon the onset of single-head spin, decreased from 15 percent by hydrogen at 300K down to about 9 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

  10. Fundamental combustion characteristics of lean hydrogen mixtures; Suiso kihaku kongoki no kisoteki nensho tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Barat, D; Kido, H; Nakahara, M; Hashimoto, J [Kyushu University, Fukuoka (Japan)

    1997-10-01

    One of the excellent combustion characteristics of hydrogen-air mixture is that its emission is free of CO2, but the problem of NOx remains, mainly caused by the high combustion temperature. Using leaner mixture and carrying out EGR are supposed to be effective methods to reduce NOx. In this study, to examine the effectiveness of the two methods, fundamental combustion characteristics of nitrogen added lean hydrogen mixtures were investigated by chemical equilibrium calculations and measurements of turbulent combustion characteristics. It is suggested that nitrogen added mixtures can achieve lower NOx combustion than lean mixtures, taking the combustion efficiency into consideration. 7 refs., 7 figs., 1 tab.

  11. The CH/π hydrogen bond: Implication in chemistry

    Science.gov (United States)

    Nishio, M.

    2012-06-01

    The CH/π hydrogen bond is the weakest extreme of hydrogen bonds that occurs between a soft acid CH and a soft base π-system. Implication in chemistry of the CH/π hydrogen bond includes issues of conformation, crystal packing, and specificity in host/guest complexes. The result obtained by analyzing the Cambridge Structural Database is reviewed. The peculiar axial preference of isopropyl group in α-phellandrene and folded conformation of levopimaric acid have been explained in terms of the CH/π hydrogen bond, by high-level ab initio MO calculations. Implication of the CH/π hydrogen bond in structural biology is also discussed, briefly.

  12. Asymptotic analysis of methane-hydrogen-air mixtures

    NARCIS (Netherlands)

    Hermanns, R.T.E.; Bastiaans, R.J.M.; Goey, de L.P.H.

    2005-01-01

    In this paper an asymptotic analysis of de Goey et al.concerning premixed stoichiometric methane-hydrogen-air flames is analyzed in depth. The analysis is performed with up to 50 mole percent of hydrogen in the fuel, at gas inlet temperatures ranging from 300 K to 650 K and pressures from 1 to 15

  13. Non-traditional Process of Hydrogen Containing Fuel Mixtures Production for Internal-combustion Engines

    Directory of Open Access Journals (Sweden)

    Gennady G. Kuvshinov

    2012-12-01

    Full Text Available The article justifies the perspectives of development of the environmentally sound technology of hydrogen containing fuel mixtures for internal-combustion engines based on the catalytic process of low-temperature decomposition of hydrocarbons into hydrogen and nanofibrous carbon.

  14. On thermal conductivity of gas mixtures containing hydrogen

    Science.gov (United States)

    Zhukov, Victor P.; Pätz, Markus

    2017-06-01

    A brief review of formulas used for the thermal conductivity of gas mixtures in CFD simulations of rocket combustion chambers is carried out in the present work. In most cases, the transport properties of mixtures are calculated from the properties of individual components using special mixing rules. The analysis of different mixing rules starts from basic equations and ends by very complex semi-empirical expressions. The formulas for the thermal conductivity are taken for the analysis from the works on modelling of rocket combustion chambers. \\hbox {H}_2{-}\\hbox {O}_2 mixtures are chosen for the evaluation of the accuracy of the considered mixing rules. The analysis shows that two of them, of Mathur et al. (Mol Phys 12(6):569-579, 1967), and of Mason and Saxena (Phys Fluids 1(5):361-369, 1958), have better agreement with the experimental data than other equations for the thermal conductivity of multicomponent gas mixtures.

  15. Measurements of the structure of an ionizing shock wave in a hydrogen-helium mixture.

    Science.gov (United States)

    Leibowitz, L. P.

    1973-01-01

    Shock structure during ionization of a hydrogen-helium mixture has been followed using hydrogen line and continuum emission measurements. A reaction scheme is proposed which includes hydrogen dissociation and a two-step excitation-ionization mechanism for hydrogen ionization by atom-atom and atom-electron collisions. Agreement has been achieved between numerical calculations and measurements of emission intensity as a function of time for shock velocities from 13 to 20 km/sec in a 0.208 H2-0.792 He mixture. The electron temperature was found to be significantly different from the heavy particle temperature during much of the ionization process. Similar time histories for H beta and continuum emission indicate upper level populations of hydrogen in equilibrium with the electron concentration during the relaxation process.

  16. Radiation induced chemical reaction of carbon monoxide and hydrogen mixture

    International Nuclear Information System (INIS)

    Sugimoto, Shun-ichi; Nishii, Masanobu

    1985-01-01

    Previous studies of radiation induced chemical reactions of CO-H 2 mixture have revealed that the yields of oxygen containing products were larger than those of hydrocarbons. In the present study, methane was added to CO-H 2 mixture in order to increase further the yields of the oxygen containing products. The yields of most products except a few products such as formaldehyde increased with the addition of small amount of methane. Especially, the yields of trioxane and tetraoxane gave the maximum values when CO-H 2 mixture containing 1 mol% methane was irradiated. When large amounts of methane were added to the mixture, the yields of aldehydes and carboxylic acids having more than two carbon atoms increased, whereas those of trioxane and tetraoxane decreased. From the study at reaction temperature over the range of 200 to 473 K, it was found that the yields of aldehydes and carboxylic acids showed maxima at 323 K. The studies on the effects of addition of cationic scavenger (NH 3 ) and radical scavenger (O 2 ) on the products yields were also carried out on the CO-H 2 -CH 4 mixture. (author)

  17. Comparison of the performance of a spark-ignited gasoline engine blended with hydrogen and hydrogen-oxygen mixtures

    International Nuclear Information System (INIS)

    Wang, Shuofeng; Ji, Changwei; Zhang, Jian; Zhang, Bo

    2011-01-01

    This paper compared the effects of hydrogen and hydrogen-oxygen blends (hydroxygen) additions on the performance of a gasoline engine at 1400 rpm and a manifolds absolute pressure of 61.5 kPa. The tests were carried out on a 1.6 L gasoline engine equipped with a hydrogen and oxygen injection system. A hybrid electronic control unit was applied to adjust the hydrogen and hydroxygen volume fractions in the intake increasing from 0% to about 3% and keep the hydrogen-to-oxygen mole ratio at 2:1 in hydroxygen tests. For each testing condition, the gasoline flow rate was adjusted to maintain the mixture global excess air ratio at 1.00. The test results confirmed that engine fuel energy flow rate was decreased after hydrogen addition but increased with hydroxygen blending. When hydrogen or hydroxygen volume fraction in the intake was lower than 2%, the hydroxygen-blended gasoline engine produced a higher thermal efficiency than the hydrogen-blended gasoline engine. Both the additions of hydrogen and hydroxygen help reduce flame development and propagation periods of the gasoline engine. HC emissions were reduced whereas NOx emissions were raised with the increase of hydrogen and hydroxygen addition levels. CO was slightly increased after hydrogen blending, but reduced with hydroxygen addition. -- Highlights: → We compared the effects of hydrogen and hydroxygen additions on the gasoline engine performance. → The hydroxygen should be added into the engine only at low blending levels. → CO is decreased with hydroxygen addition whereas increased with hydrogen blending.

  18. An experimental investigation of the rate of hydrogen absorption in zirconium-2.5 wt percent niobium from steam/hydrogen mixtures at elevated temperatures

    International Nuclear Information System (INIS)

    Langman, V.J.

    1984-08-01

    The test specifications for an experimental program to study the rate of hydrogen absorption in zirconium-2.5 weight percent niobium pressure tube material from steam/hydrogen mixtures at elevated temperatures are discussed

  19. Time evolution of cascade processes of muonic atoms in hydrogen-helium mixtures

    International Nuclear Information System (INIS)

    Bystritskij, V.; Czaplinski, W.; Filipowicz, M.; Gula, E.; Popov, N.

    1999-01-01

    Time dependence of population of muonic hydrogen states in hydrogen-helium mixtures is calculated for principal quantum number n. Number of muons transferred to helium nuclei is also determined. Dependence of population of the ground state of muonic hydrogen q ls He on time and target density and helium concentration is also considered. The results are in agreement with recent experimental data. The comparison of the calculated yield of K lines of x-ray in pure hydrogen and deuterium with experimental data indicates on essential role of Coulomb de-excitation process. Possible Stark mixing is also analyzed

  20. Low temperature catalytic combustion of natural gas - hydrogen - air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Newson, E; Roth, F von; Hottinger, P; Truong, T B [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The low temperature catalytic combustion of natural gas - air mixtures would allow the development of no-NO{sub x} burners for heating and power applications. Using commercially available catalysts, the room temperature ignition of methane-propane-air mixtures has been shown in laboratory reactors with combustion efficiencies over 95% and maximum temperatures less than 700{sup o}C. After a 500 hour stability test, severe deactivation of both methane and propane oxidation functions was observed. In cooperation with industrial partners, scaleup to 3 kW is being investigated together with startup dynamics and catalyst stability. (author) 3 figs., 3 refs.

  1. High-temperature oxidation of Zircaloy in hydrogen-steam mixtures

    International Nuclear Information System (INIS)

    Chung, H.M.; Thomas, G.R.

    1982-09-01

    Oxidation rates of Zircaloy-4 cladding tubes have been measured in hydrogen-steam mixtures at 1200 to 1700 0 C. For a given isothermal oxidation temperature, the oxide layer thicknesses have been measured as a function of time, steam supply rate, and hydrogen overpressure. The oxidation rates in the mixtures were compared with similar data obtained in pure steam and helium-steam environments under otherwise identical conditions. The rates in pure steam and helium-steam mixtures were equivalent and comparable to the parabolic rates obtained under steam-saturated conditions and reported in the literature. However, when the helium was replaced with hydrogen of equivalent partial pressure, a significantly smaller oxidation rate was observed. For high steam-supply rates, the oxidation kinetics in a hydrogen-steam mixture were parabolic, but the rate was smaller than for pure steam or helium-steam mixtures. Under otherwise identical conditions, the ratio of the parabolic rate for hydrogen-steam to that for pure steam decreased with increasing temperature and decreasing steam-supply rate

  2. Phase Diagram of Hydrogen and a Hydrogen-Helium Mixture at Planetary Conditions by Quantum Monte Carlo Simulations

    Science.gov (United States)

    Mazzola, Guglielmo; Helled, Ravit; Sorella, Sandro

    2018-01-01

    Understanding planetary interiors is directly linked to our ability of simulating exotic quantum mechanical systems such as hydrogen (H) and hydrogen-helium (H-He) mixtures at high pressures and temperatures. Equation of state (EOS) tables based on density functional theory are commonly used by planetary scientists, although this method allows only for a qualitative description of the phase diagram. Here we report quantum Monte Carlo (QMC) molecular dynamics simulations of pure H and H-He mixture. We calculate the first QMC EOS at 6000 K for a H-He mixture of a protosolar composition, and show the crucial influence of He on the H metallization pressure. Our results can be used to calibrate other EOS calculations and are very timely given the accurate determination of Jupiter's gravitational field from the NASA Juno mission and the effort to determine its structure.

  3. Selective hydrogen atom abstraction by hydrogen atoms in photolysis and radiolysis of alkane mixtures at 770 K

    International Nuclear Information System (INIS)

    Miyazaki, T.; Kinugawa, K.; Eguchi, M.; Guedes, S.M.L.

    1977-01-01

    Selective hydrogen atom abstraction reaction by H atoms, has been found in Isobutane, 2,2,3,3-tetramethylbutane(TMB), cyclopropane matrices besides neopentane matrix. The selective hydrogen atom abstraction reaction in neopentane-isobutane mixture is affected by the difference of kinetic energies of H atoms. The reaction occurs more favorably with decreasing the kinetic energy of H atoms. Competitive reaction between c-C 6 H 12 and Hi for H atoms has been studied in the radiolysis and photolysis of neo-C 5 H 12 HI mixture at 77 K. The rate constants of these reactions in neopentane matrix are quite different from these of thermal H atom reaction, but similar to those of hot H atom reaction. Importance of the selective hydrogen atom abstraction reaction by H atoms is pointed out in the radical formation in the radiolysis of pure TMB at 77 K [pt

  4. Possibility of obtaining hydrogen from coal/waste-tyre mixture

    Czech Academy of Sciences Publication Activity Database

    Kříž, Vlastimil; Brožová, Zuzana; Přibyl, Oldřich; Sýkorová, Ivana

    2008-01-01

    Roč. 89, č. 11 (2008), s. 1069-1075 ISSN 0378-3820 R&D Projects: GA ČR(CZ) GA105/07/1407 Institutional research plan: CEZ:AV0Z30460519 Keywords : hydrogen * coal * waste tyres Subject RIV: DD - Geochemistry Impact factor: 2.066, year: 2008 www.elsevier.com/locate/fuproc/

  5. Variable composition hydrogen/natural gas mixtures for increased engine efficiency and decreased emissions

    Energy Technology Data Exchange (ETDEWEB)

    Sierens, R.; Rosseel, E.

    2000-01-01

    It is well known that adding hydrogen to natural gas extends the lean limit of combustion and that in this way extremely low emission levels can be obtained: even the equivalent zero emission vehicle (EZEV) requirements can be reached. The emissions reduction is especially important at light engine loads. In this paper results are presented for a GM V8 engine. Natural gas, pure hydrogen and different blends of these two fuels have been tested. The fuel supply system used provides natural gas/hydrogen mixtures in variable proportion, regulated independently of the engine operating condition. The influence of the fuel composition on the engine operating characteristics and exhaust emissions has been examined, mainly but not exclusively for 10 and 20% hydrogen addition. At least 10% hydrogen addition is necessary for a significant improvement in efficiency. Due to the conflicting requirements for low hydrocarbons and low NO{sub x} determining the optimum hythane composition is not straight-forward. For hythane mixtures with a high hydrogen fraction, it is found that a hydrogen content of 80% or less guarantees safe engine operation (no backfire nor knock), whatever the air excess factor. It is shown that to obtain maximum engine efficiency for the whole load range while taking low exhaust emissions into account, the mixture composition should be varied with respect to engine load.

  6. Deliberate ignition of hydrogen-air-steam mixtures in condensing steam environments

    International Nuclear Information System (INIS)

    Blanchat, T.K.; Stamps, D.W.

    1997-05-01

    Large scale experiments were performed to determine the effectiveness of thermal glow plug igniters to burn hydrogen in a condensing steam environment due to the presence of water sprays. The experiments were designed to determine if a detonation or accelerated flame could occur in a hydrogen-air-steam mixture which was initially nonflammable due to steam dilution but was rendered flammable by rapid steam condensation due to water sprays. Eleven Hydrogen Igniter Tests were conducted in the test vessel. The vessel was instrumented with pressure transducers, thermocouple rakes, gas grab sample bottles, hydrogen microsensors, and cameras. The vessel contained two prototypic engineered systems: (1) a deliberate hydrogen ignition system and (2) a water spray system. Experiments were conducted under conditions scaled to be nearly prototypic of those expected in Advanced Light Water Reactors (such as the Combustion Engineering (CE) System 80+), with prototypic spray drop diameter, spray mass flux, steam condensation rates, hydrogen injection flow rates, and using the actual proposed plant igniters. The lack of any significant pressure increase during the majority of the burn and condensation events signified that localized, benign hydrogen deflagration(s) occurred with no significant pressure load on the containment vessel. Igniter location did not appear to be a factor in the open geometry. Initially stratified tests with a stoichiometric mixture in the top showed that the water spray effectively mixes the initially stratified atmosphere prior to the deflagration event. All tests demonstrated that thermal glow plugs ignite hydrogen-air-steam mixtures under conditions with water sprays near the flammability limits previously determined for hydrogen-air-steam mixtures under quiescent conditions. This report describes these experiments, gives experimental results, and provides interpretation of the results. 12 refs., 127 figs., 16 tabs

  7. Experimental study of combustion characteristics of isolated pockets of hydrogen-air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Manoubi, M.; LaFleche, M. [Univ. of Ottawa, Dept. of Mechanical Engineering, Ottawa, Ontario (Canada); Liang, Z., E-mail: zhe.liang@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Radulescu, M. [Univ. of Ottawa, Dept. of Mechanical Engineering, Ottawa, Ontario (Canada)

    2016-06-15

    This paper examines the dynamics of unconfined hydrogen-air flames and the criterion for flame propagation between neighbouring pockets of reactive gas separated by air using the soap bubble technique. The combustion events were visualized using high-speed schlieren or large-scale shadowgraph systems. It was revealed that for sufficiently lean hydrogen-air mixtures characterized by low flame speeds, buoyancy effects become important at small scales. The critical radius of hemispherical flame that will rise due to buoyancy is highly sensitive to the hydrogen concentration. The test results demonstrate that for transition of a flame between neighbouring pockets, the separation distance between the bubbles is mainly determined by the expansion ratio for near stoichiometric mixture, but it becomes much smaller for leaner mixtures because the flame kernel rises due to buoyant effects before the flame can reach the second bubble, thus the separation distance is no longer governed by the expansion ratio. (author)

  8. Effects of high heat flux hydrogen and helium mixture beam irradiation on surface modification and hydrogen retention in tungsten materials

    International Nuclear Information System (INIS)

    Tokunaga, K.; Fujiwara, T.; Ezato, K.; Suzuki, S.; Akiba, M.; Kurishita, H.; Nagata, S.; Tsuchiya, B.; Tonegawa, A.; Yoshida, N.

    2009-01-01

    High heat flux experiments using a hydrogen-helium mixture beam have been carried out on powder metallurgy tungsten (PM-W) and ultra fine grain W-TiC alloy (W-0.5 wt%TiC-H 2 ). The energy of is 18 keV. Beam flux and heat flux at the beam center is 2.0 x 10 21 atoms/m 2 s and 7.0 MW/m 2 , respectively. Typical ratio of He/D ion is 0.25. Beam duration is 1.5-3 s and interval of beam shot start is 30 s. The samples are irradiated up to a fluence of 10 22 -10 24 He/m 2 by the repeated irradiation pulses. After the irradiation, surface modification by the irradiation and hydrogen retention, surface composition have been investigated. Surface modification by hydrogen-helium mixture beams is completely different from results of single beam irradiation. In particular, mixture beam irradiation causes remarkably high hydrogen retention.

  9. Communication: Hydrogen bonding interactions in water-alcohol mixtures from X-ray absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lam, Royce K.; Smith, Jacob W.; Saykally, Richard J., E-mail: saykally@berkeley.edu [Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    2016-05-21

    While methanol and ethanol are macroscopically miscible with water, their mixtures exhibit negative excess entropies of mixing. Despite considerable effort in both experiment and theory, there remains significant disagreement regarding the origin of this effect. Different models for the liquid mixture structure have been proposed to address this behavior, including the enhancement of the water hydrogen bonding network around the alcohol hydrophobic groups and microscopic immiscibility or clustering. We have investigated mixtures of methanol, ethanol, and isopropanol with water by liquid microjet X-ray absorption spectroscopy on the oxygen K-edge, an atom-specific probe providing details of both inter- and intra-molecular structure. The measured spectra evidence a significant enhancement of hydrogen bonding originating from the methanol and ethanol hydroxyl groups upon the addition of water. These additional hydrogen bonding interactions would strengthen the liquid-liquid interactions, resulting in additional ordering in the liquid structures and leading to a reduction in entropy and a negative enthalpy of mixing, consistent with existing thermodynamic data. In contrast, the spectra of the isopropanol-water mixtures exhibit an increase in the number of broken alcohol hydrogen bonds for mixtures containing up to 0.5 water mole fraction, an observation consistent with existing enthalpy of mixing data, suggesting that the measured negative excess entropy is a result of clustering or micro-immiscibility.

  10. Communication: Hydrogen bonding interactions in water-alcohol mixtures from X-ray absorption spectroscopy

    Science.gov (United States)

    Lam, Royce K.; Smith, Jacob W.; Saykally, Richard J.

    2016-05-01

    While methanol and ethanol are macroscopically miscible with water, their mixtures exhibit negative excess entropies of mixing. Despite considerable effort in both experiment and theory, there remains significant disagreement regarding the origin of this effect. Different models for the liquid mixture structure have been proposed to address this behavior, including the enhancement of the water hydrogen bonding network around the alcohol hydrophobic groups and microscopic immiscibility or clustering. We have investigated mixtures of methanol, ethanol, and isopropanol with water by liquid microjet X-ray absorption spectroscopy on the oxygen K-edge, an atom-specific probe providing details of both inter- and intra-molecular structure. The measured spectra evidence a significant enhancement of hydrogen bonding originating from the methanol and ethanol hydroxyl groups upon the addition of water. These additional hydrogen bonding interactions would strengthen the liquid-liquid interactions, resulting in additional ordering in the liquid structures and leading to a reduction in entropy and a negative enthalpy of mixing, consistent with existing thermodynamic data. In contrast, the spectra of the isopropanol-water mixtures exhibit an increase in the number of broken alcohol hydrogen bonds for mixtures containing up to 0.5 water mole fraction, an observation consistent with existing enthalpy of mixing data, suggesting that the measured negative excess entropy is a result of clustering or micro-immiscibility.

  11. Combustion of hydrogen/air/steam mixtures in a repeated obstacle field

    International Nuclear Information System (INIS)

    Kumar, R.K.; Bowles, E.M.; Koroll, G.W.

    1994-01-01

    Combustion experiments with hydrogen/air/steam mixtures were performed in a cylindrical vessel of 1.5-m internal diameter and 5.7-m height in a repeated obstacle field. The investigations included hydrogen concentrations in the range of 10 to 20% and steam concentrations of up to 30%. For the mixtures investigated, the flame accelerated very rapidly in the vessel, reached a peak value, and decelerated equally rapidly For hydrogen/air mixtures with hydrogen concentrations above 15%, the flame speeds reached values well in excess of the sonic velocity in the mixture. Addition of steam reduced the flame speed and the peak pressure, however, the reduction was significant only for steam concentrations >20%. Experiments performed with different obstacle spacings and flow blockages indicated that flame speed decreased with increased spacing and increased with increased blockage. The effect of initial pressure on flame speed was found to be small. For a given mixture, the peak flame speed was found to be independent of the igniter location. Simple empirical correlations have been proposed to calculate the flame speeds and peak pressures in a closed vessel with closely spaces repeated obstacles. (author)

  12. Sintering uranium oxide in the reaction product of hydrogen-carbon dioxide mixtures

    International Nuclear Information System (INIS)

    De Hollander, W.R.; Nivas, Y.

    1975-01-01

    Compacted pellets of uranium oxide alone or containing one or more additives such as plutonium dioxide, gadolinium oxide, titanium dioxide, silica, and alumina are heated to 900 to 1599 0 C in the presence of a mixture of hydrogen and carbon dioxide, either alone or with an inert carrier gas and held at the desired temperature in this atmosphere to sinter the pellets. The sintered pellets are then cooled in an atmosphere having an oxygen partial pressure of 10 -4 to 10 -18 atm of oxygen such as dry hydrogen, wet hydrogen, dry carbon monoxide, wet carbon monoxide, inert gases such as nitrogen, argon, helium, and neon and mixtures of ayny of the foregoing including a mixture of hydrogen and carbon dioxide. The ratio of hydrogen to carbon dioxide in the gas mixture fed to the furnace is controlled to give a ratio of oxygen to uranium atoms in the sintered particles within the range of 1.98:1 to about 2.10:1. The water vapor present in the reaction products in the furnace atmosphere acts as a hydrolysis agent to aid removal of fluoride should such impurity be present in the uranium oxide. (U.S.)

  13. Transfer of π- from hydrogen to deuterium in H2O + D2O mixtures

    International Nuclear Information System (INIS)

    Stanislaus, S.; Measday, D.F.; Vetterli, D.; Weber, P.; Aniol, K.A.; Harston, M.R.; Armstrong, D.S.

    1989-07-01

    The transfer of stopping π - mesons from hydrogen to deuterium has been investigated in mixtures of H 2 O+D 2 O as a function of D 2 O concentration. The concentration dependence of the transfer probability is similar to that observed for the gas mixtures of H 2 and D 2 but slightly more transfer is found for H 2 O+D 2 O. (Author) 17 refs., 2 tabs., 4 figs

  14. Peculiarities of spectroscopic determination of the isotopic hydrogen composition in a mixture with neon and argon

    International Nuclear Information System (INIS)

    Nemets, V.M.; Petrov, A.A.; Solov'ev, A.A.

    1987-01-01

    The dependence of the relative intensity of atomic lines of hydrogen isotopes in the mixture with neon and argon during excitation in a high-frequency discharge under medium and high pressures is investigated. A physical model is suggested for processes determining the isotopic effects in the atomic hydrogen spectrum due to isotopic differences in velocity constants of dissociation-association, transfer and ionic-molecular reactions in a gas discharge plasma

  15. Amorphous silicon prepared from silane-hydrogen mixture

    International Nuclear Information System (INIS)

    Pietruszko, S.M.

    1982-09-01

    Amorphous silicon films prepared from a d.c. discharge of 10% SiH 4 - 90% H 2 mixture are found to have properties similar to those made from 100% SiH 4 . These films are found to be quite stable against prolonged light exposure. The effect of nitrogen on the properties of these films was investigated. It was found that instead of behaving as a classical donor, nitrogen introduces deep levels in the material. Field effect experiments on a-Si:H films at the bottom (film-substrate interface) and the top (film-vacuum interface) of the film are also reported. (author)

  16. Heterogeneous phase gamma irradiation of ethylene-hydrogen mixtures

    International Nuclear Information System (INIS)

    Molinari, M.A.; Lires, O.A.; Videla, G.J.

    1975-11-01

    Experiments of radioinduced ethylene hydrogenation were performed. The G yield of volatile saturated hydrocarbons was 0,49 for silica-gel with simultaneous irradiation and 0,09-0,05 for the other solids (silica-alumina and molecular sieve 5A). The highest yield corresponds to 4,5% of saturated products in relation to initial ammount of ethylene (silica-gel). Polymerization was the most important reaction, with yields as high as 95%. Changes in color and appearance of silica-aluminia in contact with moisture was observed, after the irradiation process. (author) [es

  17. Hydrate dissociation conditions for gas mixtures containing carbon dioxide, hydrogen, hydrogen sulfide, nitrogen, and hydrocarbons using SAFT

    International Nuclear Information System (INIS)

    Li Xiaosen; Wu Huijie; Li Yigui; Feng Ziping; Tang Liangguang; Fan Shuanshi

    2007-01-01

    A new method, a molecular thermodynamic model based on statistical mechanics, is employed to predict the hydrate dissociation conditions for binary gas mixtures with carbon dioxide, hydrogen, hydrogen sulfide, nitrogen, and hydrocarbons in the presence of aqueous solutions. The statistical associating fluid theory (SAFT) equation of state is employed to characterize the vapor and liquid phases and the statistical model of van der Waals and Platteeuw for the hydrate phase. The predictions of the proposed model were found to be in satisfactory to excellent agreement with the experimental data

  18. Laminar flame properties and flame acceleration prediction of hydrogen-methane mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Coudoro, K. [Inst. de Combustion, Aerothermique, Reactivite et Environnement CNRS Orleans (France); Inst. de Radioprotection et de Surete Nucleaire, DSR/SAGR, Fontenay-aux-Roses (France); Chaumeix, N. [Inst. de Combustion, Aerothermique, Reactivite et Environnement CNRS Orleans (France); Bentaib, A. [Inst. de Radioprotection et de Surete Nucleaire, DSR/SAGR, Fontenay-aux-Roses (France); Paillard, C-E. [Inst. de Combustion, Aerothermique, Reactivite et Environnement CNRS Orleans (France)

    2011-07-01

    The combustion of a binary mixture of methane and hydrogen has been studied using 2 different experimental setups: the spherical bomb to investigate the fundamental flame properties of this mixture with air, initially at 100 kPa, at different initial temperatures (300 - 363 K) and for a wide range of equivalence ratios (0.8 - 1.4); ENACCEF to investigate the flame acceleration phenomena in smooth tube for mixtures initially at ambient conditions and for equivalence ratios ranging between 0.57 and 0.84. A detailed kinetic mechanism has been used to derive the activation energies needed for the flame acceleration analysis. (author)

  19. Problems of hydrogen - water vapor - inert gas mixture use in heavy liquid metal coolant technology

    International Nuclear Information System (INIS)

    Ul'yanov, V.V.; Martynov, P.N.; Gulevskij, V.A.; Teplyakov, Yu.A.; Fomin, A.S.

    2014-01-01

    The reasons of slag deposit formation in circulation circuits with heavy liquid metal coolants, which can cause reactor core blockage, are considered. To prevent formation of deposits hydrogen purification of coolant and surfaces of circulation circuit is used. It consists in introduction of gaseous mixtures hydrogen - water vapor - rare gas (argon or helium) directly into coolant flow. The principle scheme of hydrogen purification and the processes occurring during it are under consideration. Measures which make it completely impossible to overlap of the flow cross section of reactor core, steam generators, pumps and other equipment by lead oxides in reactor facilities with heavy liquid metal coolants are listed [ru

  20. Feasibility study of hydrogen determination in blended gas mixture by an indigenously developed hydrogen determinator

    International Nuclear Information System (INIS)

    Gaikwad, Revati; Sonar, V.R.; Pandey, R.K.; Karekar, C.D.; Raul, Seema; Mahanty, B.; Kelkar, A.; Bhatt, R.B.; Behere, P.G.

    2017-01-01

    It is required to determine accurately the percentage composition of hydrogen in the blended gas of N 2 and H 2 prior to deliver to the sintering furnace. A feasibility study has been carried out to determine the percentage composition of hydrogen in the blended gas by using an indigenously developed hydrogen determinator. The instrument uses gas chromatograph-thermal conductivity (GC-TCD) technique to determine hydrogen. The flow of carrier gas was kept at 100 mL min -1 during the analysis. A very close agreement between the determined value and the reported value of hydrogen content in the commercially available N 2 -H 2 mixed cylinder was found by using the indigenous hydrogen determinator. (author)

  1. Condensation in gas transmission pipelines. Phase behavior of mixtures of hydrogen with natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Schouten, J.A.; Michels, J.P.J. [Amsterdam Univ. (Netherlands). Van der Waals-Zeeman Inst.; Rosmalen, R.J. van [Energy, Roden (Netherlands)

    2005-05-01

    Several pressure and temperature reductions occur along gas transmission lines. Since the pressure and temperature conditions of the natural gas in the pipeline are often close to the dew point curve, liquid dropout can occur. Injection of hydrogen into the natural gas will change the phase envelope and thus the liquid dropout. This condensation of the heavy hydrocarbons requires continuous operational attention and a positive effect of hydrogen may affect the decision to introduce hydrogen. In this paper we report on calculations of the amount of condensate in a natural gas and in this natural gas mixed with 16.7% hydrogen. These calculations have been performed at conditions prevailing in gas transport lines. The results will be used to discuss the difference in liquid dropout in a natural gas and in a mixture with hydrogen at pressure reduction stations, at crossings under waterways, at side-branching, and at separators in the pipelines. (author)

  2. The effect of fan-induced turbulence on the combustion of hydrogen-air mixtures

    International Nuclear Information System (INIS)

    Kumar, R.K.; Tamm, H.

    1984-01-01

    The effect of fan-induced turbulence on the combustion of hydrogen-air mixtures has been studied in a 2.3-m diameter sphere over a hydrogen concentration range of 4 to 42% (by volume). Two fans were used to produce the turbulence, which was measured at various lacations by hot-wire anemometry. For low hydrogen concentrations (< 7%), turbulence increases the rate and extent of combustion; for large turbulence intensities the extent of combustion approaches 100%, and combustion times are reduced by factors of 8 to 10 from those observed under quiescent conditions. At high hydrogen concentrations, the effect of turbulence on combustion time is less pronounced than at low hydrogen concentrations. Flame-generated turbulence has a significant effect on the combustion rate. (orig.)

  3. Carbon/Hydrogen ratio determination in hydrocarbons and its mixtures by electron backscattering technique

    International Nuclear Information System (INIS)

    Padron, I.; Desdin, L.F.; Navarro, A.; Fuentes, M.

    1996-01-01

    A method carbon/hydrogen ratio (C/H) determination in hydrocarbons and its mixtures was improved using the electron backscattering technique. Besides the hetero atoms (S,O and N) influence in petroleum is studied for being able to determinate the C/H ratio in cuban petroleum with high sulphur contents

  4. Measurement and modelling of hydrogen bonding in 1-alkanol plus n-alkane binary mixtures

    DEFF Research Database (Denmark)

    von Solms, Nicolas; Jensen, Lars; Kofod, Jonas L.

    2007-01-01

    Two equations of state (simplified PC-SAFT and CPA) are used to predict the monomer fraction of 1-alkanols in binary mixtures with n-alkanes. It is found that the choice of parameters and association schemes significantly affects the ability of a model to predict hydrogen bonding in mixtures, eve...... studies, which is clarified in the present work. New hydrogen bonding data based on infrared spectroscopy are reported for seven binary mixtures of alcohols and alkanes. (C) 2007 Elsevier B.V. All rights reserved....... though pure-component liquid densities and vapour pressures are predicted equally accurately for the associating compound. As was the case in the study of pure components, there exists some confusion in the literature about the correct interpretation and comparison of experimental data and theoretical...

  5. A study of chemical equilibrium of tri-component mixtures of hydrogen isotopes

    International Nuclear Information System (INIS)

    Cristescu, Ioana; Cristescu, I.; Peculea, M.

    1998-01-01

    In this paper we present a model for computing the equilibrium constants for chemical reactions between hydrogen's isotopes as function of temperature. The equilibrium constants were expressed with the aid of Gibbs potential and the partition function of the mixture. We assessed the partition function for hydrogen's isotopes having in view that some nuclei are fermions and other bosons. As results we plotted the values of equilibrium constants as function of temperature. Knowing these values we determined the deuterium distribution on species (for mixture H 2 -HD-D 2 ) as function of total deuterium concentration and the tritium distribution on species (for mixtures D 2 -DT-T 2 and H 2 -HT-T 2 ) as function of total tritium concentration. (authors)

  6. Hydrogen generation using silicon nanoparticles and their mixtures with alkali metal hydrides

    Science.gov (United States)

    Patki, Gauri Dilip

    mole of Si. We compare our silicon nanoparticles (˜10nm diameter) with commercial silicon nanopowder (rate upon decreasing the particle size to 10 nm was even greater than would be expected based upon the increase in surface area. While specific surface area increased by a factor of 6 in going from rate increased by a factor of 150. However, in all cases, silicon requires a base (e.g. NaOH, KOH, hydrazine) to catalyze its reaction with water. Metal hydrides are also promising hydrogen storage materials. The optimum metal hydride would possess high hydrogen storage density at moderate temperature and pressure, release hydrogen safely and controllably, and be stable in air. Alkali metal hydrides have high hydrogen storage density, but exhibit high uncontrollable reactivity with water. In an attempt to control this explosive nature while maintaining high storage capacity, we mixed our silicon nanoparticles with the hydrides. This has dual benefits: (1) the hydride- water reaction produces the alkali hydroxide needed for base-catalyzed silicon oxidation, and (2) dilution with 10nm coating by, the silicon may temper the reactivity of the hydride, making the process more controllable. Initially, we analyzed hydrolysis of pure alkali metal hydrides and alkaline earth metal hydrides. Lithium hydride has particularly high hydrogen gravimetric density, along with faster reaction kinetics than sodium hydride or magnesium hydride. On analysis of hydrogen production we found higher hydrogen yield from the silicon nanoparticle—metal hydride mixture than from pure hydride hydrolysis. The silicon-hydride mixtures using our 10nm silicon nanoparticles produced high hydrogen yield, exceeding the theoretical yield. Some evidence of slowing of the hydride reaction rate upon addition of silicon nanoparticles was observed.

  7. Transmission of an overdriven plane detonation in lean hydrogen-air mixtures

    International Nuclear Information System (INIS)

    Desbordes, D.; Lannoy, A.

    1988-01-01

    This paper deals with hydrogen-air explosions hazards in nuclear power plants, if PWR Loss Of Coolant Accident occurs. The main objective concerns the determination of the size of the critical diameter of transmission of a detonation propagating in a near stoechiometric H 2 -Air mixture. In such a situation the diffracting detonation is an overdriven wave. Laboratory scale simulations are described which emphasize the importance of a negative step of concentration of combustible in a mixture (stoechio to lean) on plane detonation characteristics of the lean mixture, especially the drastric reduction (i) of the size of its inrinsic tridimensional structure and (ii) correlatively that of the critical diameter of transmission of the mixture

  8. Autoignited laminar lifted flames of methane/hydrogen mixtures in heated coflow air

    KAUST Repository

    Choi, Byungchul

    2012-04-01

    Autoignited lifted flame behavior in laminar jets of methane/hydrogen mixture fuels has been investigated experimentally in heated coflow air. Three regimes of autoignited lifted flames were identified depending on initial temperature and hydrogen to methane ratio. At relatively high initial temperature, addition of a small amount of hydrogen to methane improved ignition appreciably such that the liftoff height decreased significantly. In this hydrogen-assisted autoignition regime, the liftoff height increased with jet velocity, and the characteristic flow time - defined as the ratio of liftoff height to jet velocity - correlated well with the square of the adiabatic ignition delay time. At lower temperature, the autoignited lifted flame demonstrated a unique feature in that the liftoff height decreased with increasing jet velocity. Such behavior has never been observed in lifted laminar and turbulent jet flames. A transition regime existed between these two regimes at intermediate temperature. © 2011 The Combustion Institute.

  9. Production of hydrogen through the carbonation-calcination reaction applied to CH4/CO2 mixtures

    International Nuclear Information System (INIS)

    Barelli, L.; Bidini, G.; Corradetti, A.; Desideri, U.

    2007-01-01

    The production of hydrogen combined with carbon capture represents a possible option for reducing CO 2 emissions in atmosphere and anthropogenic greenhouse effect. Nowadays the worldwide hydrogen production is based mainly on natural gas reforming, but the attention of the scientific community is focused also on other gas mixtures with significant methane content. In particular mixtures constituted mainly by methane and carbon dioxide are extensively used in energy conversion applications, as they include land-fill gas, digester gas and natural gas. The present paper addresses the development of an innovative system for hydrogen production and CO 2 capture starting from these mixtures. The plant is based on steam methane reforming, coupled with the carbonation and calcination reactions for CO 2 absorption and desorption, respectively. A thermodynamic approach is proposed to investigate the plant performance in relation to the CH 4 content in the feeding gas. The results suggest that, in order to optimize the hydrogen purity and the efficiency, two different methodologies can be adopted involving both the system layout and operating parameters. In particular such methodologies are suitable for a methane content, respectively, higher and lower than 65%

  10. Study of peculiarities of hydrogen isotopes mixture permeation through low activated steel F82H

    International Nuclear Information System (INIS)

    Kenzhin, Ye.A.; Tazhibayeva, I.L; Kulsartov, T.V.; Shestakov, V.P.; Chikhray, Ye.V.; Afanasev, S.E.; Zheldak, Yu.L.

    2003-01-01

    Full text: The problem of diffusion tritium leakage through blanket materials of future fusion device makes some constructive difficulties concerned with protection of personnel and environment and also with losses of tritium, which is planned to be used in the same device. One of the little-studied problems in the tritium leakage process in Fusion Power Plant is that in fact tritium will penetrate through materials while other hydrogen isotopes are present. These are deuterium and hydrogen which always are present in metals. Therefore, for evaluation of tritium leakage in future Fusion Power Plant under such conditions it is necessary to have experimental data about permeation of these hydrogen isotopes through the structure materials.One of proposed structure materials of fusion reactor blanket is low activated steel F82H. The experiment results on evaluation of .hydrogen, deuterium and its mixture interaction parameters with steel F82H are shown in this work. The tests were carried out within temperature range 273-973 K under inlet hydrogen pressure of 100-2000 Pa. Diffusivity, deuterium and hydrogen permeation constants for low activated steel F82H was determined from experiment results. Those experimental results were used for created phenomenology model which describes hydrogen isotope penetration through tube sample from hydrogen isotopes mixture. That model was used so determining the ratios of desorption rates (D-D, D-H, H-H) on outlet side of sample. Using of so obtained results, we can correctly evaluate, the titanium leakage from blanket of fusion machine which will be constructed using low activated steel F82H

  11. Change of hydrogen bonding structure in ionic liquid mixtures by anion type

    Science.gov (United States)

    Cha, Seoncheol; Kim, Doseok

    2018-05-01

    Ionic liquid mixtures have gained attention as a way of tuning material properties continuously with composition changes. For some mixture systems, physicochemical properties such as excess molar volume have been found to be significantly different from the value expected by linear interpolation, but the origin of this deviation is not well understood yet. The microstructure of the mixture, which can range from an ideal mixture of two initial consisting ionic liquids to a different structure from those of pure materials, has been suggested as the origin of the observed deviation. The structures of several different ionic liquid mixtures are studied by IR spectroscopy to confirm this suggestion, as a particular IR absorption band (νC(2)-D) for the moiety participating in the hydrogen bonding changes sensitively with the change of the anion in the ionic liquid. The absorbance of νC(2)-D changes proportionally with the composition, and a relatively small excess molar volume is observed for the mixtures containing an electronegative halide anion. By contrast, the absorbance changes nonlinearly, and the excess molar volumes are larger for the mixtures of which one of the anions has multiple interaction sites.

  12. Effects of hydrogen mixture into helium gas on deuterium removal from lithium titanate

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, Akihito, E-mail: tsuchiya@frontier.hokudai.ac.jp [Laboratory of Plasma Physics and Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo 060-8628 (Japan); Hino, Tomoaki; Yamauchi, Yuji; Nobuta, Yuji [Laboratory of Plasma Physics and Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo 060-8628 (Japan); Akiba, Masato; Enoeda, Mikio [Japan Atomic Energy Agency, 801-1, Mukoyama, Naka 311-0193 (Japan)

    2013-10-15

    Lithium titanate (Li{sub 2}TiO{sub 3}) pebbles were irradiated with deuterium ions with energy of 1.7 keV and then exposed to helium or helium–hydrogen mixed gas at various temperatures, in order to evaluate the effects of gas exposure on deuterium removal from the pebbles. The amounts of residual deuterium in the pebbles were measured by thermal desorption spectroscopy. The mixing of hydrogen gas into helium gas enhanced the removal amount of deuterium. In other words, the amount of residual deuterium after the helium–hydrogen mixed gas exposure at lower temperature was lower than that after the helium gas exposure. In addition, we also evaluated the pebbles exposed to the helium gas with different hydrogen mixture ratio from 0% to 1%, at 573 K. Although the amount of residual deuterium in the pebbles after the exposure decreased with increasing the hydrogen mixture ratio, the implanted deuterium partly remained after the exposure. These results suggest that the tritium inventory may occur at low temperature region in the blanket during the operation.

  13. Gaseous carburising of self-passivating Fe–Cr-Ni alloys in acetylene-hydrogen mixtures

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Hummelshøj, Thomas Strabo; Somers, Marcel A. J.

    2011-01-01

    temperatures, carbon stabilised expanded austenite develops, which has high hardness, while retaining the corrosion performance of the untreated alloy; for relatively high temperatures, Cr based carbides develop, and eventually, the material deteriorates by metal dusting corrosion.......Gaseous carburising of self-passivating Fe–Cr–Ni alloys in acetylene–hydrogen was investigated for temperatures up to 823 K. Acetylene–hydrogen gas mixtures allow both the activation of the surface and the subsequent carburising at a high and adjustable carburising potential. For relatively low...

  14. Combustion of lean hydrogen-air mixtures in the connected compartments

    International Nuclear Information System (INIS)

    Fan Liu; Yoshio Yoshizawa; Akio Miyori; Kenya Kubota

    1997-01-01

    A study of combustion experiments with premixed lean hydrogen-air mixtures was conducted in a vessel consisting of two compartments connected by a diameter-variable vent. Effects of various parameters (hydrogen concentration, vent diameter and initial pressure) on mechanical loads of the combustion processes including mainly the peak pressures and the rates of pressure rise were investigated. Relation of flow and combustion was approached. Ignition-combustion processes were discussed, and the combustion types were classified into three patterns according to the pressure-time histories and the flow characteristics in main combustion compartment

  15. Hydrogen: implications for the future automobile

    International Nuclear Information System (INIS)

    Frise, P. R.; Woodward, W.

    2004-01-01

    'Full text:' The presentation will focus upon the challenges within the automotive manufacturing industry related to the hydrogen fuelled automobile of the future. Challenges and opportunities include issues of power train design and packaging as well as on-road performance capabilities, fuel system packaging and materials for body structures. Due to the size and complexity of the automotive sector, technology changes tend to be evolutionary rather than revolutionary, but changes are being made to today's cars in preparation for the evolution toward the future hydrogen automobile. Real world applications of new technologies will be described that are assisting automakers to prepare for the hydrogen future today. The work will be described in the context of AUTO21, a national Network of Centres of Excellence (NCE), is helping to position Canada as a leader in automotive research and development. More than 250 researchers in 34 Canadian universities and over 110 industry and government partners contribute to AUTO21 through applied research projects in six themes of study ranging from health and societal issues to pure engineering applications. (author)

  16. First-Principles Petascale Simulations for Predicting Deflagration to Detonation Transition in Hydrogen-Oxygen Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Khokhlov, Alexei [Univ. of Chicago, IL (United States). Dept. of Astronomy and Astrophysics. Enrico Fermi Inst.; Austin, Joanna [Argonne National Lab. (ANL), Argonne, IL (United States). Argonne Leadership Computing Facility; Bacon, C. [Univ. of Illinois, Urbana, IL (United States). Dept. of Aerospace Engineering

    2015-03-02

    Hydrogen has emerged as an important fuel across a range of industries as a means of achieving energy independence and to reduce emissions. DDT and the resulting detonation waves in hydrogen-oxygen can have especially catastrophic consequences in a variety of industrial and energy producing settings related to hydrogen. First-principles numerical simulations of flame acceleration and DDT are required for an in-depth understanding of the phenomena and facilitating design of safe hydrogen systems. The goals of this project were (1) to develop first-principles petascale reactive flow Navier-Stokes simulation code for predicting gaseous high-speed combustion and detonation (HSCD) phenomena and (2) demonstrate feasibility of first-principles simulations of rapid flame acceleration and deflagration-to-detonation transition (DDT) in stoichiometric hydrogen-oxygen mixture (2H2 + O2). The goals of the project have been accomplished. We have developed a novel numerical simulation code, named HSCD, for performing first-principles direct numerical simulations of high-speed hydrogen combustion. We carried out a series of validating numerical simulations of inert and reactive shock reflection experiments in shock tubes. We then performed a pilot numerical simulation of flame acceleration in a long pipe. The simulation showed the transition of the rapidly accelerating flame into a detonation. The DDT simulations were performed using BG/Q Mira at the Argonne National Laboratory, currently the fourth fastest super-computer in the world.

  17. Silicon surface damage caused by reactive ion etching in fluorocarbon gas mixtures containing hydrogen

    International Nuclear Information System (INIS)

    Norstroem, H.; Blom, H.; Ostling, M.; Nylandsted Larsen, A.; Keinonen, J.; Berg, S.

    1991-01-01

    For selective etching of SiO 2 on silicon, gases or gas mixtures containing hydrogen are often used. Hydrogen from the glow discharge promotes the formation of a thin film polymer layer responsible for the selectivity of the etching process. The reactive ion etch (RIE) process is known to create damage in the silicon substrate. The influence of hydrogen on the damage and deactivation of dopants is investigated in the present work. The distribution of hydrogen in silicon, after different etching and annealing conditions have been studied. The influence of the RIE process on the charge carrier concentration in silicon has been investigated. Various analytical techniques like contact resistivity measurements, four point probe measurements, and Hall measurements have been used to determine the influence of the RIE process on the electrical properties of processed silicon wafers. The hydrogen profile in as-etched and post annealed wafers was determined by the 1 H( 15 N,αγ) 12 C nuclear reaction. The depth of the deactivated surface layer is discussed in terms of the impinging hydrogen ion energy, i.e., the possibility of H + ions to pick up an energy equal to the peak-to-peak voltage of the rf signal

  18. Evidence for phase separation of ethanol-water mixtures at the hydrogen terminated nanocrystalline diamond surface.

    Science.gov (United States)

    Janssens, Stoffel D; Drijkoningen, Sien; Saitner, Marc; Boyen, Hans-Gerd; Wagner, Patrick; Larsson, Karin; Haenen, Ken

    2012-07-28

    Interactions between ethanol-water mixtures and a hydrophobic hydrogen terminated nanocrystalline diamond surface, are investigated by sessile drop contact angle measurements. The surface free energy of the hydrophobic surface, obtained with pure liquids, differs strongly from values obtained by ethanol-water mixtures. Here, a model which explains this difference is presented. The model suggests that, due to a higher affinity of ethanol for the hydrophobic surface, when compared to water, a phase separation occurs when a mixture of both liquids is in contact with the H-terminated diamond surface. These results are supported by a computational study giving insight in the affinity and related interaction at the liquid-solid interface.

  19. Experimental Study of Gas Explosions in Hydrogen Sulfide-Natural Gas-Air Mixtures

    Directory of Open Access Journals (Sweden)

    André Vagner Gaathaug

    2014-01-01

    Full Text Available An experimental study of turbulent combustion of hydrogen sulfide (H2S and natural gas was performed to provide reference data for verification of CFD codes and direct comparison. Hydrogen sulfide is present in most crude oil sources, and the explosion behaviour of pure H2S and mixtures with natural gas is important to address. The explosion behaviour was studied in a four-meter-long square pipe. The first two meters of the pipe had obstacles while the rest was smooth. Pressure transducers were used to measure the combustion in the pipe. The pure H2S gave slightly lower explosion pressure than pure natural gas for lean-to-stoichiometric mixtures. The rich H2S gave higher pressure than natural gas. Mixtures of H2S and natural gas were also studied and pressure spikes were observed when 5% and 10% H2S were added to natural gas and also when 5% and 10% natural gas were added to H2S. The addition of 5% H2S to natural gas resulted in higher pressure than pure H2S and pure natural gas. The 5% mixture gave much faster combustion than pure natural gas under fuel rich conditions.

  20. Assessment of methods for analyzing gaseous mixtures of hydrogen isotopes and helium

    International Nuclear Information System (INIS)

    Attalla, A.; Bishop, C.T.; Bohl, D.R.; Buxton, T.L.; Sprague, R.E.; Warner, D.K.

    1976-01-01

    Mass spectrographic methods have served well in the past to analyze gaseous mixtures of the hydrogen isotopes. Alternate methods of analyses are reviewed which offer wider ranges and variety of isotopic determinations. This report describes possible improvements of the mass spectrographic determinations, gas chromatography, anti-Stokes Raman spectroscopy, microwave-induced optical emission spectroscopy, and methods of measuring tritium using radiation detection devices. Precision, accuracy, limitations, and costs are included for some of the methods mentioned. Costs range from $70,000 for the anti-Stokes Raman spectroscopy equipment, which can determine hydrogen isotopes but not helium, to less than $10,000 for the gas chromatographic equipment, which can determine hydrogen isotopes and helium with precision and accuracy comparable to those of the mass spectrometer

  1. Method to separate off hydrogen fluoride from a uranium hexafluoride-hydrogen fluoride mixture

    International Nuclear Information System (INIS)

    Pfistermeister, M.; Jokar, J.

    1979-01-01

    There have been sofar difficulties involved in separating off HF when purifying UF 6 . According to the invention, this can be achieved without great expenditure if one adds a perfluorated amine or derivative of it to the UF 6 -HF mixture. The UF 6 can be separated by simple distillation or sublimation from the hardly-volatile formed tri-(perfluoro-butyl) ammonium fluoride. The adduct formed can be easily split again with NaOH so that the amine can be recycled without loss. (UWI) [de

  2. Ignitability of hydrogen/oxygen/diluent mixtures in the presence of hot surfaces

    International Nuclear Information System (INIS)

    Kumar, R.K.; Koroll, G.W.

    1995-01-01

    In the licensing process for CANDU nuclear power stations it is necessary to demonstrate tolerance to a wide range of low-probability accidents. These include loss of moderator accidents that may lead to the formation of flammable mixtures of deuterium, oxygen, helium, and steam in the reactor calandria vessel. Uncovered adjuster or control rods are considered as possible sources of ignition when a flammable mixture is present. A knowledge of the minimum hot-surface temperature required for ignition is important in assessing the reactor safety. These hot surface temperatures were measured using electrically heated adjuster rod simulators in a large spherical vessel (2.3-m internal diameter). Whereas the effects of geometry on ignition temperature were studied in the large-scale apparatus, some of the effects, such as those produced by a strong radiation field, were studied using a small-scale apparatus. Investigations carried our over a range of hydrogen and diluent concentrations indicated that, although the ignition temperatures were fairly insensitive to the hydrogen concentration, they were strongly affected by the presence of steam The addition of 30% steam to a dry combustible mixture increased the minimum surface temperature required for ignition by approximates 100 degrees C of the diluents investigated, steam had the most effect on ignition. The effect of initial temperature of the mixture on the ignition temperature was small, whereas the effect of initial pressure was significant. The effect of substituting deuterium for hydrogen on ignition temperature was small. The effect of a high-intensity gamma-radiation field on the minimum hot-surface temperature required for ignition was investigated using a 2-dm 3 ignition vessel placed in a linear accelerator. Radiation had no measurable effect on ignition temperature

  3. Molar excess volumes of liquid hydrogen and neon mixtures from path integral simulation

    International Nuclear Information System (INIS)

    Challa, S.R.; Johnson, J.K.

    1999-01-01

    Volumetric properties of liquid mixtures of neon and hydrogen have been calculated using path integral hybrid Monte Carlo simulations. Realistic potentials have been used for the three interactions involved. Molar volumes and excess volumes of these mixtures have been evaluated for various compositions at 29 and 31.14 K, and 30 atm. Significant quantum effects are observed in molar volumes. Quantum simulations agree well with experimental molar volumes. Calculated excess volumes agree qualitatively with experimental values. However, contrary to the existing understanding that large positive deviations from ideal mixtures are caused due to quantum effects in Ne - H 2 mixtures, both classical as well as quantum simulations predict the large positive deviations from ideal mixtures. Further investigations using two other Ne - H 2 potentials of Lennard - Jones (LJ) type show that excess volumes are very sensitive to the cross-interaction potential. We conclude that the cross-interaction potential employed in our simulations is accurate for volumetric properties. This potential is more repulsive compared to the two LJ potentials tested, which have been obtained by two different combining rules. This repulsion and a comparatively lower potential well depth can explain the positive deviations from ideal mixing. copyright 1999 American Institute of Physics

  4. Separation of gaseous hydrogen from a water-hydrogen mixture in a fuel cell power system operating in a weightless environment

    Science.gov (United States)

    Romanowski, William E. (Inventor); Suljak, George T. (Inventor)

    1989-01-01

    A fuel cell power system for use in a weightless environment, such as in space, includes a device for removing water from a water-hydrogen mixture condensed from the exhaust from the fuel cell power section of the system. Water is removed from the mixture in a centrifugal separator, and is fed into a holding, pressure operated water discharge valve via a Pitot tube. Entrained nondissolved hydrogen is removed from the Pitot tube by a bleed orifice in the Pitot tube before the water reaches the water discharge valve. Water discharged from the valve thus has a substantially reduced hydrogen content.

  5. Analysis of hydrogen-deuterium mixtures and of mixtures of heavy-water and light-water by means of a mass spectrometer

    International Nuclear Information System (INIS)

    Chenouard, J.; Gueron, J.; Roth, E.

    1951-07-01

    The differences between hydrogen and deuterium with respect to the capture of thermal neutrons (hydrogen = 0.31 barn; deuterium 0.00065 barn) explains the interest of detecting small variations of the isotopic composition of the heavy waters used in the Chatillon nuclear pile. The aim of this report is to describe and discuss the method used since more than a year for the dosimetry of heavy waters. After a recall of the principle of mass spectroscopy analysis of deuterium-hydrogen mixtures, the preciseness of the results is presented and the balancing method used for the determination of the isotopic composition of hydrogen-deuterium mixtures is explained in detail. Finally, a brief comparison of the preciseness of mass spectroscopy measurements with the analyses made with other methods is performed. Some calculations and the tables of results are presented in appendixes. (J.S.)

  6. High pressure oxidation of sponge-Zr in steam/hydrogen mixtures

    International Nuclear Information System (INIS)

    Kim, Y.S.

    1997-01-01

    A thermogravimetric apparatus for operation in 1 and 70 atm steam-hydrogen or steam-helium mixtures was used to investigate the oxidation kinetics of sponge-Zr containing 215 ppm Fe. Weight-gain rates, reflecting both oxygen and hydrogen uptake, were measured in the temperature range 350-400 C. The specimens consisted of thin sponge-Zr layers metallurgically bonded to a Zircaloy disk. The edges of the disk specimens were coated with a thin layer of pure gold to avoid the deleterious effect of corners. Following each experiment, the specimens were examined metallographically to reveal the morphology of the oxide and/or hydride formed. Two types of oxide, one black and uniform and the other white and nodular, were observed on sponge-Zr surfaces oxidized in steam environments at 70 atm. The oxidation rate when white-nodular oxide formed was a factor of two higher than that of black-uniform oxide at 400 C for steam contents above 1 mol%. The oxidation rate was independent of total pressure, the carrier gas (H 2 or He) and steam content above ∝1 mol%. The oxidation kinetics of sponge-Zr follows a linear law for maximum reaction times up to ∝6 days. The oxidation rate in steam-hydrogen mixtures at 70 atm total pressure decreases when the steam content approaches the steam-starved region (∝0.5 mol% steam at 400 C and ∝0.02 mol% steam at 350 C). Lower steam concentrations cause massive hydriding of the specimens. Even at steam concentrations above the critical value, direct hydrogen absorption from the gas was manifest by hydrogen pickup fractions greater than unity. (orig.)

  7. Efficient Discovery of Novel Multicomponent Mixtures for Hydrogen Storage: A Combined Computational/Experimental Approach

    Energy Technology Data Exchange (ETDEWEB)

    Wolverton, Christopher [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering; Ozolins, Vidvuds [Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering; Kung, Harold H. [Northwestern Univ., Evanston, IL (United States). Dept. of Chemical and Biological Engineering; Yang, Jun [Ford Scientific Research Lab., Dearborn, MI (United States); Hwang, Sonjong [California Inst. of Technology (CalTech), Pasadena, CA (United States). Dept. of Chemistry and Chemical Engineering; Shore, Sheldon [The Ohio State Univ., Columbus, OH (United States). Dept. of Chemistry and Biochemistry

    2016-11-28

    The objective of the proposed program is to discover novel mixed hydrides for hydrogen storage, which enable the DOE 2010 system-level goals. Our goal is to find a material that desorbs 8.5 wt.% H2 or more at temperatures below 85°C. The research program will combine first-principles calculations of reaction thermodynamics and kinetics with material and catalyst synthesis, testing, and characterization. We will combine materials from distinct categories (e.g., chemical and complex hydrides) to form novel multicomponent reactions. Systems to be studied include mixtures of complex hydrides and chemical hydrides [e.g. LiNH2+NH3BH3] and nitrogen-hydrogen based borohydrides [e.g. Al(BH4)3(NH3)3]. The 2010 and 2015 FreedomCAR/DOE targets for hydrogen storage systems are very challenging, and cannot be met with existing materials. The vast majority of the work to date has delineated materials into various classes, e.g., complex and metal hydrides, chemical hydrides, and sorbents. However, very recent studies indicate that mixtures of storage materials, particularly mixtures between various classes, hold promise to achieve technological attributes that materials within an individual class cannot reach. Our project involves a systematic, rational approach to designing novel multicomponent mixtures of materials with fast hydrogenation/dehydrogenation kinetics and favorable thermodynamics using a combination of state-of-the-art scientific computing and experimentation. We will use the accurate predictive power of first-principles modeling to understand the thermodynamic and microscopic kinetic processes involved in hydrogen release and uptake and to design new material/catalyst systems with improved properties. Detailed characterization and atomic-scale catalysis experiments will elucidate the effect of dopants and nanoscale catalysts in achieving fast kinetics and reversibility. And

  8. Conversion rate of para-hydrogen to ortho-hydrogen by oxygen: implications for PHIP gas storage and utilization.

    Science.gov (United States)

    Wagner, Shawn

    2014-06-01

    To determine the storability of para-hydrogen before reestablishment of the room temperature thermal equilibrium mixture. Para-hydrogen was produced at near 100% purity and mixed with different oxygen quantities to determine the rate of conversion to the thermal equilibrium mixture of 75: 25% (ortho: para) by detecting the ortho-hydrogen (1)H nuclear magnetic resonance using a 9.4 T imager. The para-hydrogen to ortho-hydrogen velocity constant, k, near room temperature (292 K) was determined to be 8.27 ± 1.30 L/mol · min(-1). This value was calculated utilizing four different oxygen fractions. Para-hydrogen conversion to ortho-hydrogen by oxygen can be minimized for long term storage with judicious removal of oxygen contamination. Prior calculated velocity rates were confirmed demonstrating a dependence on only the oxygen concentration.

  9. Reduced-order modellin for high-pressure transient flow of hydrogen-natural gas mixture

    Science.gov (United States)

    Agaie, Baba G.; Khan, Ilyas; Alshomrani, Ali Saleh; Alqahtani, Aisha M.

    2017-05-01

    In this paper the transient flow of hydrogen compressed-natural gas (HCNG) mixture which is also referred to as hydrogen-natural gas mixture in a pipeline is numerically computed using the reduced-order modelling technique. The study on transient conditions is important because the pipeline flows are normally in the unsteady state due to the sudden opening and closure of control valves, but most of the existing studies only analyse the flow in the steady-state conditions. The mathematical model consists in a set of non-linear conservation forms of partial differential equations. The objective of this paper is to improve the accuracy in the prediction of the HCNG transient flow parameters using the Reduced-Order Modelling (ROM). The ROM technique has been successfully used in single-gas and aerodynamic flow problems, the gas mixture has not been done using the ROM. The study is based on the velocity change created by the operation of the valves upstream and downstream the pipeline. Results on the flow characteristics, namely the pressure, density, celerity and mass flux are based on variations of the mixing ratio and valve reaction and actuation time; the ROM computational time cost advantage are also presented.

  10. INVESTIGATION OF COMBUSTION, PERFORMANCE AND EMISSION CHARACTERISTICS OF SPARK IGNITION ENGINE FUELLED WITH BUTHANOL – GASOLINE MIXTURE AND A HYDROGEN ENRICHED AIR

    OpenAIRE

    Alfredas Rimkus; Mindaugas Melaika; Jonas Matijošius; Šarūnas Mikaliūnas; Saugirdas Pukalskas

    2016-01-01

    In this study, spark ignition engine fuelled with buthanol-gasoline mixture and a hydrogen-enriched air was investigated. Engine performance, emissions and combustion characteristics were investigated with different buthanol (10% and 20% by volume) gasoline mixtures and additionally supplied oxygen and hydrogen (HHO) gas mixture (3.6 l/min) in the sucked air. Hydrogen, which is in the HHO gas, improves gasoline and gasoline-buthanol mixture combustion, increases indicated pressure during comb...

  11. Purification of hydrogen under a free or combined form in a gaseous mixture, by chemical reactions with uranium

    International Nuclear Information System (INIS)

    Caron Charles, M.

    1988-03-01

    Within the framework of the european fusion program, we are dealing with the purification of hydrogen (tritium) under a free or combined form, from a H 2 , N 2 , NH 3 , CH 4 , O 2 , gaseous mixture. The process consists in cracking the hydrogenated molecules and absorbing the impurities by chemical reactions with uranium, without holding back hydrogen. In the temperature range: 950 K [fr

  12. Validation of a mixture-averaged thermal diffusion model for premixed lean hydrogen flames

    Science.gov (United States)

    Schlup, Jason; Blanquart, Guillaume

    2018-03-01

    The mixture-averaged thermal diffusion model originally proposed by Chapman and Cowling is validated using multiple flame configurations. Simulations using detailed hydrogen chemistry are done on one-, two-, and three-dimensional flames. The analysis spans flat and stretched, steady and unsteady, and laminar and turbulent flames. Quantitative and qualitative results using the thermal diffusion model compare very well with the more complex multicomponent diffusion model. Comparisons are made using flame speeds, surface areas, species profiles, and chemical source terms. Once validated, this model is applied to three-dimensional laminar and turbulent flames. For these cases, thermal diffusion causes an increase in the propagation speed of the flames as well as increased product chemical source terms in regions of high positive curvature. The results illustrate the necessity for including thermal diffusion, and the accuracy and computational efficiency of the mixture-averaged thermal diffusion model.

  13. Quantifying Ab Initio Equation of State Errors for Hydrogen-Helium Mixtures

    Science.gov (United States)

    Clay, Raymond; Morales, Miguel

    2017-06-01

    In order to produce predictive models of Jovian planets, an accurate equation of state for hydrogen-helium mixtures is needed over pressure and temperature ranges spanning multiple orders of magnitude. While extensive theoretical work has been done in this area, previous controversies regarding the equation of state of pure hydrogen have demonstrated exceptional sensitivity to approximations commonly employed in ab initio calculations. To this end, we present the results of our quantum Monte Carlo based benchmarking studies for several major classes of density functionals. Additionally, we expand upon our published results by considering the impact that ionic finite size effects and density functional errors translate to errors in the equation of state. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  14. Equilibrium based analytical model for estimation of pressure magnification during deflagration of hydrogen air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Karanam, Aditya; Sharma, Pavan K.; Ganju, Sunil; Singh, Ram Kumar [Bhabha Atomic Research Centre (BARC), Mumbai (India). Reactor Safety Div.

    2016-12-15

    During postulated accident sequences in nuclear reactors, hydrogen may get released from the core and form a flammable mixture in the surrounding containment structure. Ignition of such mixtures and the subsequent pressure rise are an imminent threat for safe and sustainable operation of nuclear reactors. Methods for evaluating post ignition characteristics are important for determining the design safety margins in such scenarios. This study presents two thermo-chemical models for determining the post ignition state. The first model is based on internal energy balance while the second model uses the concept of element potentials to minimize the free energy of the system with internal energy imposed as a constraint. Predictions from both the models have been compared against published data over a wide range of mixture compositions. Important differences in the regions close to flammability limits and for stoichiometric mixtures have been identified and explained. The equilibrium model has been validated for varied temperatures and pressures representative of initial conditions that may be present in the containment during accidents. Special emphasis has been given to the understanding of the role of dissociation and its effect on equilibrium pressure, temperature and species concentrations.

  15. Equilibrium based analytical model for estimation of pressure magnification during deflagration of hydrogen air mixtures

    International Nuclear Information System (INIS)

    Karanam, Aditya; Sharma, Pavan K.; Ganju, Sunil; Singh, Ram Kumar

    2016-01-01

    During postulated accident sequences in nuclear reactors, hydrogen may get released from the core and form a flammable mixture in the surrounding containment structure. Ignition of such mixtures and the subsequent pressure rise are an imminent threat for safe and sustainable operation of nuclear reactors. Methods for evaluating post ignition characteristics are important for determining the design safety margins in such scenarios. This study presents two thermo-chemical models for determining the post ignition state. The first model is based on internal energy balance while the second model uses the concept of element potentials to minimize the free energy of the system with internal energy imposed as a constraint. Predictions from both the models have been compared against published data over a wide range of mixture compositions. Important differences in the regions close to flammability limits and for stoichiometric mixtures have been identified and explained. The equilibrium model has been validated for varied temperatures and pressures representative of initial conditions that may be present in the containment during accidents. Special emphasis has been given to the understanding of the role of dissociation and its effect on equilibrium pressure, temperature and species concentrations.

  16. An investigation of turbulent catalytically stabilized channel flow combustion of lean hydrogen - air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Mantzaras, I; Benz, P; Schaeren, R; Bombach, R [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The catalytically stabilised thermal combustion (CST) of lean hydrogen-air mixtures was investigated numerically in a turbulent channel flow configuration using a two-dimensional elliptic model with detailed heterogeneous and homogeneous chemical reactions. Comparison between turbulent and laminar cases having the same incoming mean properties shows that turbulence inhibits homogeneous ignition due to increased heat transport away from the near-wall layer. The peak root-mean-square temperature and species fluctuations are always located outside the extent of the homogeneous reaction zone indicating that thermochemical fluctuations have no significant influence on gaseous combustion. (author) 4 figs., 6 refs.

  17. Separation of molecular hydrogen isotope mixtures using zeolite NaX-3M

    International Nuclear Information System (INIS)

    Polevoj, A.S.; Yudin, I.P.

    1984-01-01

    The components of transfer unit height (TUH) at separation of the H 2 -D 2 mixture using zeolite NaX-3M in the countercurrent column are determined. It is shown that the interphase isotopic exchange in the column is limited by gaseous diffusion in sorbent primary pores. On the basis of the TUH dependence the value of the hydrogen diffusion coefficient in primary pores of NaX-3M zeolite equal at 77 K and 87.3 K, respectively, approximately 1.09x10 -15 and approximately 1.69x10 -15 m 2 /s is calculated

  18. An experimental investigation of the isochoric heat capacity of superheated steam and mixtures of superheated steam and hydrogen gas

    International Nuclear Information System (INIS)

    Nowak, E.S.; Chan, J.S.

    1975-01-01

    Measurements on the specific heat at constant volume of superheated steam and hydrogen gas mixtures at concentrations varying from 1.6 to 0.8 moles of water vapor per mole of hydrogen gas were made for temperatures ranging from 240 to 400 deg C. It was found that the experimental specific heat values of the mixtures are in good agreement with the ideal mixture values only near the saturation temperature of steam. The difference between the measured and the calculated ideal mixture values is a function of temperature, pressure and composition varying from about 11 to 24% at conditions far removed from the saturation temperature of steam. This indicates the heat of mixing is of significance in the steam-hydrogen system

  19. Mixture

    Directory of Open Access Journals (Sweden)

    Silva-Aguilar Martín

    2011-01-01

    Full Text Available Metals are ubiquitous pollutants present as mixtures. In particular, mixture of arsenic-cadmium-lead is among the leading toxic agents detected in the environment. These metals have carcinogenic and cell-transforming potential. In this study, we used a two step cell transformation model, to determine the role of oxidative stress in transformation induced by a mixture of arsenic-cadmium-lead. Oxidative damage and antioxidant response were determined. Metal mixture treatment induces the increase of damage markers and the antioxidant response. Loss of cell viability and increased transforming potential were observed during the promotion phase. This finding correlated significantly with generation of reactive oxygen species. Cotreatment with N-acetyl-cysteine induces effect on the transforming capacity; while a diminution was found in initiation, in promotion phase a total block of the transforming capacity was observed. Our results suggest that oxidative stress generated by metal mixture plays an important role only in promotion phase promoting transforming capacity.

  20. Characterisation of laser ignition in hydrogen-air mixtures in a combustion bomb

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Dhananjay Kumar; Agarwal, Avinash Kumar [Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur-208016 (India); Weinrotter, Martin; Wintner, Ernst [Photonics Institute, Vienna University of Technology, Gusshausstrasse 27, A-1040 Vienna (Austria); Iskra, Kurt [Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz (Austria)

    2009-03-15

    Laser-induced spark ignition of lean hydrogen-air mixtures was experimentally investigated using nanosecond pulses generated by Q-switched Nd:YAG laser (wavelength 1064 nm) at initial pressure of 3 MPa and temperature 323 K in a constant volume combustion chamber. Laser ignition has several advantages over conventional ignition systems especially in internal combustion engines, hence it is necessary to characterise the combustion phenomena from start of plasma formation to end of combustion. In the present experimental investigation, the formation of laser plasma by spontaneous emission technique and subsequently developing flame kernel was measured. Initially, the plasma propagates towards the incoming laser. This backward moving plasma (towards the focusing lens) grows much faster than the forward moving plasma (along the direction of laser). A piezoelectric pressure transducer was used to measure the pressure rise in the combustion chamber. Hydrogen-air mixtures were also ignited using a spark plug under identical experimental conditions and results are compared with the laser ignition ones. (author)

  1. Combustion of stratified hydrogen-air mixtures in the 10.7 m3 Combustion Test Facility cylinder

    International Nuclear Information System (INIS)

    Whitehouse, D.R.; Greig, D.R.; Koroll, G.W.

    1996-01-01

    This paper presents preliminary results from hydrogen concentration gradient combustion experiments in a 10.7 m 3 cylinder. These gradients, also referred to as stratified mixtures, were formed from dry mixtures of hydrogen and air at atmospheric temperature. Combustion pressures, burn fractions and flame speeds in concentration gradients were compared with combustion of well-mixed gases containing equivalent amounts of hydrogen. The studied variables included the quantity of hydrogen in the vessel, the steepness of the concentration gradient, the igniter location, and the initial concentration of hydrogen at the bottom of the vessel. Gradients of hydrogen and air with average concentrations of hydrogen below the downward propagation limit produced significantly greater combustion pressures when ignited at the top of the vessel than well-mixed gases with the same quantity of hydrogen. This was the result of considerably higher burn fractions in the gradients than in the well-mixed gas tests. Above the downward propagation limit, gradients of hydrogen ignited at the top of the vessel produced nearly the same combustion pressures as under well-mixed conditions; both gradients and well-mixed gases had high burn fractions. Much higher flame speeds were observed in the gradients than the well-mixed gases. Gradients and well-mixed gases containing up to 14% hydrogen ignited at the bottom of the vessel produced nearly the same combustion pressures. Above 14% hydrogen, gradients produced lower combustion pressures than well-mixed gases having the same quantity of hydrogen. This can be attributed to lower burn fractions of fuel from the gradients compared with well-mixed gases with similar quantities of hydrogen. When ignited at the bottom of the vessel, 90% of a gradient's gases remained unburned until several seconds after ignition. The remaining gases were then consumed at a very fast rate. (orig.)

  2. Flame acceleration of hydrogen - air - diluent mixtures at middle scale using ENACCEF: experiments and modelling

    International Nuclear Information System (INIS)

    Fabrice Malet; Nathalie Lamoureux; Nabiha Djebaili-Chaumeix; Claude-Etienne Paillard; Pierre Pailhories; Jean-Pierre L'heriteau; Bernard Chaumont; Ahmed Bentaib

    2005-01-01

    Full text of publication follows: In the case of hypothetic severe accident on light water nuclear reactor, hydrogen would be produced during reactor core degradation and released to the reactor building which could subsequently raise a combustion hazard. A local ignition of the combustible mixture would give birth initially to a slow flame which can be accelerated due to turbulence. Depending on the geometry and the premixed combustible mixture composition, the flame can accelerate and for some conditions transit to detonation or be quenched after a certain distance. The flame acceleration is responsible for the generation of high pressure loads that could damage the reactor's building. Moreover, geometrical configuration is a major factor leading to flame acceleration. Thus, recording experimental data notably on mid-size installations is required for the numeric simulations validation before modelling realistic scales. The ENACCEF vertical facility is a 6 meters high acceleration tube aimed at representing steam generator room leading to containment dome. This setup can be equipped with obstacles of different blockage ratios and shapes in order to obtain an acceleration of the flame. Depending on the geometrical characteristics of these obstacles, different regimes of the flame propagation can be achieved. The mixture composition's influence on flame velocity and acceleration has been investigated. Using a steam physical-like diluent (40% He - 60% CO 2 ), influence of dilution on flame speed and acceleration has been investigated. The flame front has also been recorded with ultra fast ombroscopy visualization, both in the tube and in dome's the entering. The flame propagation is computed using the TONUS code. Based on Euler's equation solving code using structured finite volumes, it includes the CREBCOM flames modelling and simulates the hydrogen/air turbulent flame propagation, taking into account 3D complex geometry and reactants concentration gradients. Since

  3. Influence of carbon monoxide additions on the sensitivity of the dry hydrogen-air mixtures to detonation

    International Nuclear Information System (INIS)

    Magzumov, A.E.; Kirillov, I.A.; Fridman, A.A.; Rusanov, V.D.

    1995-01-01

    Under severe accident conditions of water cooled nuclear reactors the hydrogen-air detonation represents one of the most hazardous events which can result in the reactor containment damage. An important factor related with the measure of gas mixture detonability is the detonation cell size which correlates with the critical tube diameter and detonation initiation energy. A numerical kinetic study is presented of the influence of carbon monoxide admixtures (from 0 vol.% to 40 vol.%) upon the sensitivity (detonation cell size) of the dry hydrogen-air gas mixtures to detonation in post-accident containment atmosphere. (author). 3 refs., 3 figs

  4. Time-resolved output spectrum from a hydrogen fluoride laser using mixtures of SF6 and HI

    International Nuclear Information System (INIS)

    Greiner, N.R.

    1975-01-01

    The time-resolved spectrum from a transverse-discharge hydrogen fluoride (HF) laser using a mixture of SF 6 and HI is reported. Because this spectrum matches that from a high-pressure H 2 -F 2 laser, and because the SF 6 -HI mixture is chemically stable, this laser should be a suitable and convenient source for probing H 2 -F 2 amplifiers

  5. Neutrino results from the Fermilab 15-foot bubble chamber using neon-hydrogen mixtures

    International Nuclear Information System (INIS)

    Burnett, T.H.

    1977-01-01

    Neutrino results from the FNAL 15-foot bubble chamber, using two different neon-hydrogen mixtures are reviewed. Included are the measurements from four different experiments of the dilepton, or μe rate, which appear to be consistent with the charm production interpretation for this process. Also mentioned is a study of the scaling variable distributions for antineutrinos, which shows no anomalous threshold, consistent with the usual four-quark model, but indicates a slight scale breaking. The ratio of anti νn to anti νp cross sections has been extracted from the same data and is also consistent with the quark model. A study of the hadronic state produced by electron (anti)neutrinos in neon is summarized, with the conclusion that nuclear rescattering effects are the same as for hadron interactions. (orig.) [de

  6. Analysis of Auto ignition of Hydrogen-Air Mixture using Direct Numerical Simulation; Analisis de la Autoignicion de Mezclas Hidrogeno-Aire mediante Simulacion Numerica directa

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Vera, I.; Paola, G. de; Jimenez Sanchez, C.

    2008-07-01

    This document reproduces the final project of Ignacio Hernandez Vera, presented on September 25, 2008, for the obtention of the engineer degree of the Carlos III University of Madrid. A study on the auto ignition process of different hydrogen-air mixtures for different simple geometries is carried out by means of direct numerical simulation. Auto ignition time is compared for different configurations and it is discussed the influence that different parameters have on it, such as temperature or transport phenomena. Afterwards a new reduced chemical mechanism for the simulation of this phenomenon is tested and assessed. Finally the mixing and ignition process is tackled using different mixture fractions and its implications on the construction of combustion models briefly discussed. (Author) 15 refs.

  7. COMPARATIVE STUDY OF ANTIBACTERIAL ACTIVITY OF PEROXYDISUCCINIC ACID, HYDROGEN PEROXIDE AND THEIR MIXTURE

    Directory of Open Access Journals (Sweden)

    Blazheyevskiy M.Ye.,

    2016-06-01

    Full Text Available Introduction. It is known that reactive oxygen species (ROS generated in vivo by cell aerobic metabolism cause multiple damage in different cell organelles and kill not only obligate anaerobes and microaerophilles, but also aerobes. ROS generated by phagocytes and representatives of normal microflora are an important component of macroorganism defense from most pathogens, which is explained by their ability to damage different biological structures. ROS have high reactivity and let us use them in vitro as effective biocides. Hydrogen peroxide is widely used in many industries, in particular, in medicine and veterinary as antiseptic and disinfectant agent due to its safety for environment and broad spectrum of antimicrobial activity including spore-forming bacteria. However, in the recent years certain decrease of background sensitivity of microorganisms to hydrogen peroxide and occurrence of resistant strains of pathogenic microorganisms to this agent has been noted. The aim of this work is to carry out a comparative study of antimicrobial activity of hydrogen peroxide, peroxydisuccinic acid (PDSA, monoperoxysuccinic acid (MPSA, and mixture of PDSA and hydrogen peroxide (Н2О2. Materials and methods. The substances of peroxydisuccinic acid (PDSA and monoperoxysuccinic acid (MPSA were prepared by well known methods. The following test-strains were used to assess antimicrobial activity of the agents: Staphylococcus aureus АТСС 25923, Escherichia coli АТСС 25922, Pseudomonas aeruginosa АТСС 27853, Pseudomonas aeruginosa АТСС 9027, Basillus сereus АТСС 10702, Basillus сereus АТСС 96, Basillus subtilis АТСС 6633, Proteus vulgaris ATCC 4636, Candida albicans АТСС 885/653, and Candida albicans АТСС 10231. All disinfectant agents were diluted in distilled water at 40 ºС and stirred. The microbial burden was 2∙109 CFU/ml of the medium, and for kinetic studies 105 CFU/ml of the medium, it was standardizing

  8. Separation of molecular hydrogen isotope mixtures on zeolite NaX-3M

    International Nuclear Information System (INIS)

    Polevoj, A.S.; Yudin, I.P.

    1984-01-01

    The transfer unito height (TUH) have been determined at separation of the H 2 -D 2 mixture using zeolite NaX-3M depending on temperature and linear gas flow rate in the column. Experimentally the TUH value has been determined by the method of stepped variation of the concentration of one of the separated components at the entrance into the column and measurement of the substance front wash-out at the outlet. The results of determining TUH in the column of 10 mm diameter filled by the zeolite immobile layer with granules of 2-3 mm size show that with increasing the temperature from 77 K to 87.3 K TUH decreases while at constant temperature it increases with the growth of linear gas flow rate. The mentioned above circumstances testify to the essential contribution to the TUH value of the hydrogen diffusion process in the sorbent grain. The given TUH absolute values indicate the high rate of interphase isotope exchange at separation of the H 2 -D 2 mixture using NaX-3M zeolite

  9. High pressure hydriding of sponge-Zr in steam-hydrogen mixtures

    International Nuclear Information System (INIS)

    Kim, Y.S.

    1997-01-01

    Hydriding kinetics of thin sponge-Zr layers metallurgically bonded to a Zircaloy disk has been studied by thermogravimetry in the temperature range 350-400 C in 7 MPa hydrogen-steam mixtures. Some specimens were prefilmed with a thin oxide layer prior to exposure to the reactant gas; all were coated with a thin layer of gold to avoid premature reaction at edges. Two types of hydriding were observed in prefilmed specimens, viz., a slow hydrogen absorption process that precedes an accelerated (massive) hydriding. At 7 MPa total pressure, the critical ratio of H 2 /H 2 O above which massive hydriding occurs at 400 C is ∝200. The critical H 2 /H 2 O ratio is shifted to ∝2.5 x 10 3 at 350 C. The slow hydriding process occurs only when conditions for hydriding and oxidation are approximately equally favorable. Based on maximum weight gain, the specimen is completely converted to δ-ZrH 2 by massive hydriding in ∝5 h at a hydriding rate of ∝10 -6 mol H/cm 2 s. Incubation times of 10-20 h prior to the onset of massive hydriding increases with prefilm oxide thickness in the range of 0-10 μm. By changing to a steam-enriched gas, massive hydriding that initially started in a steam-starved condition was arrested by re-formation of a protective oxide scale. (orig.)

  10. Dynamic study of excited state hydrogen-bonded complexes of harmane in cyclohexane-toluene mixtures.

    Science.gov (United States)

    Carmona, Carmen; Balón, Manuel; Galán, Manuel; Guardado, Pilar; Muñoz, María A

    2002-09-01

    Photoinduced proton transfer reactions of harmane or 1-methyl-9H-pyrido[3,4-b]indole (HN) in the presence of the proton donor hexafluoroisopropanol (HFIP) in cyclohexane-toluene mixtures (CY-TL; 10% vol/vol of TL) have been studied. Three excited state species have been identified: a 1:2 hydrogen-bonded proton transfer complex (PTC), between the pyridinic nitrogen of the substrate and the proton donor, a hydrogen-bonded cation-like exciplex (CL*) with a stoichiometry of at least 1:3 and a zwitterionic exciplex (Z*). Time-resolved fluorescence measurements evidence that upon excitation of ground state PTC, an excited state equilibrium is established between PTC* and the cationlike exciplex, CL*, lambdaem approximately/= 390 nm. This excited state reaction is assisted by another proton donor molecule. Further reaction of CL* with an additional HFIP molecule produces the zwitterionic species, Z*, lambda(em) approximately/= 500 nm. From the analysis of the multiexponential decays, measured at different emission wavelengths and as a function of HFIP concentration, the mechanism of these excited state reactions has been established. Thus, three rate constants and three reciprocal lifetimes have been determined. The simultaneous study of 1,9-dimethyl-9H-pyrido[3,4-b]indole (MHN) under the same experimental conditions has helped to understand the excited state kinetics of these processes.

  11. Calculation of radiative opacity of plasma mixtures using a relativistic screened hydrogenic model

    International Nuclear Information System (INIS)

    Mendoza, M.A.; Rubiano, J.G.; Gil, J.M.; Rodríguez, R.; Florido, R.; Espinosa, G.; Martel, P.; Mínguez, E.

    2014-01-01

    We present the code ATMED based on an average atom model and conceived for fast computing the population distribution and radiative properties of hot and dense single and multicomponent plasmas under LTE conditions. A relativistic screened hydrogenic model (RSHM), built on a new set of universal constants considering j-splitting, is used to calculate the required atomic data. The opacity model includes radiative bound–bound, bound–free, free–free, and scattering processes. Bound–bound line-shape function has contributions from natural, Doppler and electron-impact broadenings. An additional dielectronic broadening to account for fluctuations in the average level populations has been included, which improves substantially the Rosseland mean opacity results. To illustrate the main features of the code and its capabilities, calculations of several fundamental quantities of one-component plasmas and mixtures are presented, and a comparison with previously published data is performed. Results are satisfactorily compared with those predicted by more elaborate codes. - Highlights: • A new opacity code, ATMED, based on the average atom approximation is presented. • Atomic data are computed by means of a relativistic screened hydrogenic model. • An effective bound level degeneracy is included for accounting pressure ionization. • A new dielectronic line broadening is included to improve the mean opacities. • ATMED has the possibility to handle with single element and multicomponent plasmas

  12. Hydrogen generation from Al-NiCl2/NaBH4 mixture affected by lanthanum metal.

    Science.gov (United States)

    Sun, Wen Qiang; Fan, Mei-Qiang; Fei, Yong; Pan, Hua; Wang, Liang Liang; Yao, Jun

    2012-01-01

    The effect of La on Al/NaBH(4) hydrolysis was elaborated in the present paper. Hydrogen generation amount increases but hydrogen generation rate decreases with La content increasing. There is an optimized composition that Al-15 wt% La-5 wt% NiCl(2)/NaBH(4) mixture (Al-15 wt% La-5 wt% NiCl(2)/NaBH(4) weight ratio, 1 : 3) has 126 mL g(-1 )min(-1) maximum hydrogen generation rate and 1764 mL g(-1) hydrogen generation amount within 60 min. The efficiency is 88%. Combined with NiCl(2), La has great effect on NaBH(4) hydrolysis but has little effect on Al hydrolysis. Increasing La content is helpful to decrease the particle size of Al-La-NiCl(2) in the milling process, which induces that the hydrolysis byproduct Ni(2)B is highly distributed into Al(OH)(3) and the catalytic reactivity of Ni(2)B/Al(OH)(3) is increased therefore. But hydrolysis byproduct La(OH)(3) deposits on Al surface and leads to some side effect. The Al-La-NiCl(2)/NaBH(4) mixture has good stability in low temperature and its hydrolytic performance can be improved with increasing global temperature. Therefore, the mixture has good safety and can be applied as on board hydrogen generation material.

  13. Isotopic analysis of H{sub 2}, HD, D{sub 2} mixtures and analysis of ortho-para-hydrogen mixtures by gas chromatography; Dosages par chromatographie en phase gazeuse de melanges d'hydrogene, d'hydrogene deutere, de deuterium et de melanges ortho-para-hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Botter, F; Perriere, G de la; Tistchenko, S [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    This communication describes the present situation concerning the possibilities of vapor phase chromatography for the separation and analysis of mixtures of H{sub 2}, HD and D{sub 2} and of ortho- and para-hydrogen mixtures. Separation factors for physical adsorption of the various varieties of hydrogen have been deduced from chromatograms and have also been measured directly with a static method - the agreements is good. (author) [French] Le present rapport decrit diverses possibilites qu'offre la chromatographie gazeuse d'elution en ce qui concerne le dosage des melanges H{sub 2}, HD, D{sub 2} et des varietes ortho et para de l'hydrogene. On a calcule, a partir des chromatogrammes obtenus, les facteurs de separation par adsorption physique des differentes varietes d'hydrogene, et compare aux facteurs de separation determines par mesure directe. (auteur)

  14. Some problems on materials tests in high temperature hydrogen base gas mixture

    International Nuclear Information System (INIS)

    Shikama, Tatsuo; Tanabe, Tatsuhiko; Fujitsuka, Masakazu; Yoshida, Heitaro; Watanabe, Ryoji

    1980-01-01

    Some problems have been examined on materials tests (creep rupture tests and corrosion tests) in high temperature mixture gas of hydrogen (80%H 2 + 15%CO + 5%CO 2 ) simulating the reducing gas for direct steel making. H 2 , CO, CO 2 and CH 4 in the reducing gas interact with each other at elevated temperature and produce water vapor (H 2 O) and carbon (soot). Carbon deposited on the walls of retorts and the water condensed at pipings of the lower temperature gas outlet causes blocking of gas flow. The gas reactions have been found to be catalyzed by the retort walls, and appropriate selection of the materials for retorts has been found to mitigate the problems caused by water condensation and carbon deposition. Quartz has been recognized to be one of the most promising materials for minimizing the gas reactions. And ceramic coating, namely, BN (born nitride) on the heat resistant superalloy, MO-RE II, has reduced the amounts of water vapor and deposited carbon (sooting) produced by gas reactions and has kept dew points of outlet gas below room temperature. The well known emf (thermo-electromotive force) deterioration of Alumel-Chromel thermocouples in the reducing gases at elevated temperatures has been also found to be prevented by the ceramic (BN) coating. (author)

  15. Properties of hotspots in plasma focus discharges operating in hydrogen-argon mixtures

    International Nuclear Information System (INIS)

    Silva, P; Favre, M

    2002-01-01

    We have investigated the properties of hotspots formed in low energy plasma focus (PF) discharges operating in hydrogen-argon mixtures, at 140 kA current level. A combination of filtered pinhole and slit-wire camera is used to measure the hotspot size and temperature. The results show that the best conditions for reproducible and localized hotspot formation are obtained by adjusting the base pressure in such a way that the mass load allows the time of first radial collapse to coincide with peak current. When the PF is operated with 20% argon content, rather uniform hotspots, of 115 μm characteristic size and 300 eV characteristic temperature, are produced with a better than 80% reproducibility in their axial localization. The electron density in the hotspots is estimated to be ∼10 20 cm -3 . Calculations performed with a CRE code indicate that a significant fraction of the radiation is emitted in the 3.2 to 3.88 keV region, corresponding to K α emission from highly ionized argon

  16. Tritium release from advanced beryllium materials after loading by tritium/hydrogen gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Chakin, Vladimir, E-mail: vladimir.chakin@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Rolli, Rolf; Moeslang, Anton; Kurinskiy, Petr; Vladimirov, Pavel [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Dorn, Christopher [Materion Beryllium & Composites, 6070 Parkland Boulevard, Mayfield Heights, OH 44124-4191 (United States); Kupriyanov, Igor [Bochvar Russian Scientific Research Institute of Inorganic Materials, Rogova str., 5, 123098 Moscow (Russian Federation)

    2016-06-15

    Highlights: • A major tritium release peak for beryllium samples occurs at temperatures higher than 1250 K. • A beryllium grade with comparatively smaller grain size has a comparatively higher tritium release compared to the grade with larger grain size. • The pebbles of irregular shape with the grain size of 10–30 μm produced by the crushing method demonstrate the highest tritium release rate. - Abstract: Comparison of different beryllium samples on tritium release and retention properties after high-temperature loading by tritium/hydrogen gas mixture and following temperature-programmed desorption (TPD) tests has been performed. The I-220-H grade produced by hot isostatic pressing (HIP) having the smallest grain size, the pebbles of irregular shape with the smallest grain size (10–30 μm) produced by the crushing method (CM), and the pebbles with 1 mm diameter produced by the fluoride reduction method (FRM) having a highly developed inherent porosity show the highest release rate. Grain size and porosity are considered as key structural parameters for comparison and ranking of different beryllium materials on tritium release and retention properties.

  17. A study on the reaction of Zircaloy-4 tube with hydrogen/steam mixture

    Science.gov (United States)

    Lee, Ji-Min; Kook, Dong-Hak; Cho, Il-Je; Kim, Yong-Soo

    2017-08-01

    In order to fundamentally understand the secondary hydriding mechanism of zirconium alloy cladding, the reaction of commercial Zircaloy-4 tubes with hydrogen and steam mixture was studied using a thermo-gravimetric analyser with two variables, H2/H2O ratio and temperature. Phenomenological analysis revealed that in the steam starvation condition, i.e., when the H2/H2O ratio is greater than 104, hydriding is the dominant reaction and the weight gain increases linearly after a short incubation time. On the other hand, when the gas ratio is 5 × 102 or 103, both hydriding and oxidation reactions take place simultaneously, leading to three distinct regimes: primary hydriding, enhanced oxidation, and massive hydriding. Microstructural changes of oxide demonstrate that when the weight gain exceeds a certain critical value, massive hydriding takes place due to the significant localized crack development within the oxide, which possibly simulates the secondary hydriding failure in a defective fuel operation. This study reveals that the steam starvation condition above the critical H2/H2O ratio is only a necessary condition for the secondary hydriding failure and, as a sufficient condition, oxide needs to grow sufficiently to reach the critical thickness that produces substantial crack development. In other words, in a real defective fuel operation incident, the secondary failure is initiated only when both steam starvation and oxide degradation conditions are simultaneously met. Therefore, it is concluded that the indispensable time for the critical oxide growth primarily determines the triggering time of massive hydriding failure.

  18. Thermodynamic diagrams for high temperature plasmas of air, air-carbon, carbon-hydrogen mixtures, and argon

    CERN Document Server

    Kroepelin, H; Hoffmann, K-U

    2013-01-01

    Thermodynamic Diagrams for High Temperature Plasmas of Air, Air-Carbon, Carbon-Hydrogen Mixtures, and Argon provides information relating to the properties of equilibrium gas plasmas formed from hydrocarbons, from air without argon, from pure argon, and from mixtures of air and carbon at various compositions, temperatures and pressures. The data are presented in graphical rather than tabular form to provide a clearer picture of the plasma processes investigated. This book is composed of four chapters, and begins with the introduction to the characteristics of plasmas, with emphasis on their th

  19. Thermophysical properties of hydrogen-helium mixtures: re-examination of the mixing rules via quantum molecular dynamics simulations.

    Science.gov (United States)

    Wang, Cong; He, Xian-Tu; Zhang, Ping

    2013-09-01

    Thermophysical properties of hydrogen, helium, and hydrogen-helium mixtures have been investigated in the warm dense matter regime at electron number densities ranging from 6.02 × 10^{29} ∼ 2.41 × 10^{30} m^{-3} and temperatures from 4000 to 20000 K via quantum molecular dynamics simulations. We focus on the dynamical properties such as the equation of states, diffusion coefficients, and viscosity. Mixing rules (density matching, pressure matching, and binary ionic mixing rules) have been validated by checking composite properties of pure species against that of the fully interacting mixture derived from quantum molecular dynamics simulations. These mixing rules reproduce pressures within 10% accuracy, while it is 75% and 50% for the diffusion and viscosity, respectively. The binary ionic mixing rule moves the results into better agreement. Predictions from one component plasma model are also provided and discussed.

  20. On detonation dynamics in hydrogen-air-steam mixtures: Theory and application to Olkiluoto reactor building

    International Nuclear Information System (INIS)

    Silde, A.; Lindholm, I.

    2000-02-01

    This report consists of the literature study of detonation dynamics in hydrogen-air-steam mixtures, and the assessment of shock pressure loads in Olkiluoto 1 and 2 reactor building under detonation conditions using the computer program DETO developed during this work at VTT. The program uses a simple 1-D approach based on the strong explosion theory, and accounts for the effects of both the primary or incident shock and the first (oblique or normal) reflected shock from a wall structure. The code results are also assessed against a Balloon experiment performed at Germany, and the classical Chapman-Jouguet detonation theory. The whole work was carried out as a part of Nordic SOS-2.3 project, dealing with severe accident analysis. The initial conditions and gas distribution of the detonation calculations are based on previous severe accident analyses by MELCOR and FLUENT codes. According to DETO calculations, the maximum peak pressure in a structure of Olkiluoto reactor building room B60-80 after normal shock reflection was about 38.7 MPa if a total of 3.15 kg hydrogen was assumed to burned in a distance of 2.0 m from the wall structure. The corresponding pressure impulse was about 9.4 kPa-s. The results were sensitive to the distance used. Comparison of the results to classical C-J theory and the Balloon experiments suggested that DETO code represented a conservative estimation for the first pressure spike under the shock reflection from a wall in Olkiluoto reactor building. Complicated 3-D phenomena of shock wave reflections and focusing, nor the propagation of combustion front behind the shock wave under detonation conditions are not modeled in the DETO code. More detailed 3-D analyses with a specific detonation code are, therefore, recommended. In spite of the code simplifications, DETO was found to be a beneficial tool for simple first-order assessments of the structure pressure loads under the first reflection of detonation shock waves. The work on assessment

  1. Experimental study on the natural gas dual fuel engine test and the higher the mixture ratio of hydrogen to natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B.S.; Lee, Y.S.; Park, C.K. [Cheonnam University, Kwangju (Korea); Masahiro, S. [Kyoto University, Kyoto (Japan)

    1999-05-28

    One of the unsolved problems of the natural gas dual fuel engine is that there is too much exhaust of Total Hydrogen Carbon(THC) at a low equivalent mixture ratio. To fix it, a natural gas mixed with hydrogen was applied to engine test. The results showed that the higher the mixture ratio of hydrogen to natural gas, the higher the combustion efficiency. And when the amount of the intake air is reached to 90% of WOT, the combustion efficiency was promoted. But, like a case making the injection timing earlier, the equivalent mixture ratio for the nocking limit decreases and the produce of NOx increases. 5 refs., 9 figs., 1 tab.

  2. Hydrogen Generation from Al-NiCl2/NaBH4 Mixture Affected by Lanthanum Metal

    Directory of Open Access Journals (Sweden)

    Wen Qiang Sun

    2012-01-01

    Full Text Available The effect of La on Al/NaBH4 hydrolysis was elaborated in the present paper. Hydrogen generation amount increases but hydrogen generation rate decreases with La content increasing. There is an optimized composition that Al-15 wt% La-5 wt% NiCl2/NaBH4 mixture (Al-15 wt% La-5 wt% NiCl2/NaBH4 weight ratio, 1 : 3 has 126 mL g−1 min−1 maximum hydrogen generation rate and 1764 mL g−1 hydrogen generation amount within 60 min. The efficiency is 88%. Combined with NiCl2, La has great effect on NaBH4 hydrolysis but has little effect on Al hydrolysis. Increasing La content is helpful to decrease the particle size of Al-La-NiCl2 in the milling process, which induces that the hydrolysis byproduct Ni2B is highly distributed into Al(OH3 and the catalytic reactivity of Ni2B/Al(OH3 is increased therefore. But hydrolysis byproduct La(OH3 deposits on Al surface and leads to some side effect. The Al-La-NiCl2/NaBH4 mixture has good stability in low temperature and its hydrolytic performance can be improved with increasing global temperature. Therefore, the mixture has good safety and can be applied as on board hydrogen generation material.

  3. A separation process for hydrogen fluoride from its mixtures with 1,1,1-trifluoro-2-chloroethane

    Energy Technology Data Exchange (ETDEWEB)

    Galland, J.M.; Perdriau, R.; Rouzies, D.

    1994-03-11

    When decanting the mixture of hydrogen fluoride (HF) and 1,1,1-trifluoro-2-chloroethane (F133a) at a temperature between -40 deg C and -10 deg C, a lower organic phase, poor in HF, and a superior phase, rich in HF, are obtained (the reaction may be activated with trichlorethylen); the superior phase can be directly recycled in the fluorination reactor or distilled in order to separate the HF-F133a azeotrope (the head), which is sent back to the decanter, and a quasi-pure HF (the ends). The lower phase distillation produces HF-F133a (head) and a mixture of F133a and trichlorethylen (ends); this mixture is then distilled and pure F133a is separated from trichlorethylen. 9 p., 2 fig.

  4. Gas-chromatographic separation of hydrogen isotopes mixtures on capillary molecular sieve 5 A column at 173 K

    International Nuclear Information System (INIS)

    Bidica, N.; Preda, A.; Stanciu, V.

    2002-01-01

    Analysis of a gas mixture of hydrogen species, is not too easy because the differences in their physical-chemical properties are very small; the most different are their masses, and consequently most common analytical method appear to be the mass-spectrometry. However, the impossibility to distinguish between two ions (atomic or molecular) with the same mass renders this method as unapplicable. Another problem is the decay of tritium with production of 3 He. These disadvantages of mass-spectrometry have made that other analytical methods, like gas chromatography, to be considered and developed. Thus, there are many papers about various chromatographic columns especially prepared for hydrogen species separation but the preparation and treatment of these columns are very difficult to reproduce. Besides these, there are two other main disadvantages: column operating temperature is very low and long retention times for hydrogen species (more than half an hour) are required. However, the gas-chromatography method still remains an appropriate one. The method described in this paper was based on using a capillary molecular sieve 5A column which has been operated for this kind of separation. The retention times were relatively short, about 8-9 minutes. The carrier gas was Ne and the detector - TCD. In the paper chromatograms for various carrier flow rates and various hydrogen isotope mixtures are presented. The results demonstrated a quite good efficiency for H 2 , HD, D 2 and a not very good one for orthoH 2 -paraH 2 . (authors)

  5. Configuration and technology implications of potential nuclear hydrogen system applications.

    Energy Technology Data Exchange (ETDEWEB)

    Conzelmann, G.; Petri, M.; Forsberg, C.; Yildiz, B.; ORNL

    2005-11-05

    Nuclear technologies have important distinctions and potential advantages for large-scale generation of hydrogen for U.S. energy services. Nuclear hydrogen requires no imported fossil fuels, results in lower greenhouse-gas emissions and other pollutants, lends itself to large-scale production, and is sustainable. The technical uncertainties in nuclear hydrogen processes and the reactor technologies needed to enable these processes, as well waste, proliferation, and economic issues must be successfully addressed before nuclear energy can be a major contributor to the nation's energy future. In order to address technical issues in the time frame needed to provide optimized hydrogen production choices, the Nuclear Hydrogen Initiative (NHI) must examine a wide range of new technologies, make the best use of research funding, and make early decisions on which technology options to pursue. For these reasons, it is important that system integration studies be performed to help guide the decisions made in the NHI. In framing the scope of system integration analyses, there is a hierarchy of questions that should be addressed: What hydrogen markets will exist and what are their characteristics? Which markets are most consistent with nuclear hydrogen? What nuclear power and production process configurations are optimal? What requirements are placed on the nuclear hydrogen system? The intent of the NHI system studies is to gain a better understanding of nuclear power's potential role in a hydrogen economy and what hydrogen production technologies show the most promise. This work couples with system studies sponsored by DOE-EE and other agencies that provide a basis for evaluating and selecting future hydrogen production technologies. This assessment includes identifying commercial hydrogen applications and their requirements, comparing the characteristics of nuclear hydrogen systems to those market requirements, evaluating nuclear hydrogen configuration options

  6. Co-pyrolysis of waste tire/coal mixtures for smokeless fuel, maltenes and hydrogen-rich gas production

    International Nuclear Information System (INIS)

    Bičáková, Olga; Straka, Pavel

    2016-01-01

    Highlights: • Co-pyrolysis of waste tires/coal mixtures yields mainly smokeless fuel (55–74 wt%). • Alternatively, the smokeless fuel can serve as carbonaceous sorbent. • The obtained tar contained maltenes (80–85 wt%) and asphaltenes (6–8 wt%). • Tar from co-pyrolysis can serve as heating oil or a source of maltenes for repairing of asphalt surfaces. • The hydrogen-rich gas was obtained (61–65 vol% H_2, 24–25 vol% CH_4, 1.4–2 vol% CO_2). - Abstract: The processing of waste tires with two different types of bituminous coal was studied through the slow co-pyrolysis of 1 kg of waste tire/coal mixtures with 15, 30 and 60 wt% waste tires on a laboratory scale. The waste tire/coal mixtures were pyrolysed using a quartz reactor in a stationary bed. The mixtures were heated at a rate 5 °C/min up to the final temperature of 900 °C with a soaking time of 30 min at the required temperature. The mass balance of the process and the properties of the coke and tar obtained were evaluated, further, the influence of the admixture in the charge on the amount and composition of the obtained coke and tar was determined. It was found that the smokeless fuel/carbonaceous sorbent and a high yield of tar for further use can be obtained through the slow co-pyrolysis. The obtained tars contained mostly maltenes (80–85 wt%). FTIR analysis showed that the maltenes from the co-pyrolysis of coal/waste tires exhibited significantly lower aromaticity as compared with that from coal alone. The gas obtained from pyrolysis or co-pyrolysis of waste tire/coal mixtures contained a high amount of hydrogen (above 60 vol%) and methane (above 20 vol%).

  7. Vapor-liquid equilibrium prediction with pseudo-cubic equation of state for binary mixtures containing hydrogen, helium, or neon

    Energy Technology Data Exchange (ETDEWEB)

    Kato, M.; Tanaka, H. (Nihon Univ.,Fukushima, (Japan). Faculty of Enineering)

    1990-03-01

    As an equation of state of vapor-liquid equilibrium, an original pseudo-cubic equation of state was previously proposed by the authors of this report and its study is continued. In the present study, new effective critical values of hydrogen, helium and neon were determined empirically from vapor-liquid equilibrium data of literature values against their critical temperatures, critical pressures and critical volumes. The vapor-liquid equilibrium relations of binary system quantum gas mixtures were predicted combining the conventinal pseudo-cubic equation of state and the new effective critical values, and without using binary heteromolecular interaction parameter. The predicted values of hydrogen-ethylene, helium-propane and neon-oxygen systems were compared with literature values. As a result, it was indicated that the vapor-liquid relations of binary system mixtures containing hydrogen, helium and neon can be predicted with favorable accuracy combining the effective critical values and the three parameter pseudo-cubic equation of state. 37 refs., 3 figs., 4 tabs.

  8. Comparison and evaluation of methods for the determination of flammability limits, applied to methane/hydrogen/air mixtures

    International Nuclear Information System (INIS)

    Schoor, F. van den; Hermanns, R.T.E.; Oijen, J.A. van; Verplaetsen, F.; Goey, L.P.H. de

    2008-01-01

    Different methods, both experimental and numerical, to determine the flammability limits are compared and evaluated, exemplified by a determination of the flammability limits of methane/hydrogen/air mixtures for hydrogen fuel molar fractions of 0, 0.2, 0.4 and 0.6, at atmospheric pressure and ambient temperature. Two different experimental methods are used. The first method uses a glass tube with visual observation of the flame, whereas the second method uses a closed spherical vessel with a pressure rise criterion to determine whether flame propagation has occurred. In addition to these experiments, the flammability limits are determined numerically. Unsteady planar and spherically expanding flames are calculated with a one-dimensional flame code with the inclusion of radiation heat loss in the optically thin limit. Comparison of the experimental results with the results of the planar flame calculations shows large differences, especially for lean mixtures. These differences increase with increasing hydrogen content in the fuel. Better agreement with the experimental results is found for the spherically expanding flame calculations. A limiting burning velocity of 5 cm/s is found to predict the upper flammability limit determined with the tube method very well, whereas the limiting flame temperature approach was found to give poorer agreement. Further analysis indicates that the neglect of flame front instabilities is the probable cause of the large differences between experimental and numerical results at the lower flammability limit

  9. Oxidation and Destruction of Polyvinyl Alcohol under the Combined Action of Ozone-Oxygen Mixture and Hydrogen Peroxide

    Science.gov (United States)

    Zimin, Yu. S.; Kutlugil'dina, G. G.; Mustafin, A. G.

    2018-03-01

    The oxidative transformations of a polyvinyl alcohol in aqueous solutions are studied under the simultaneous action of the two oxidizing agents, an ozone-oxygen mixture and a hydrogen peroxide. Effective parameters a and b, which characterize the first and second channels of carboxyl group accumulation, respectively, grow linearly upon an increase in the initial concentration of H2O2. After the temperature dependence of a and b parameters (331-363 K) in a PVA + O3 + O2 + H2O2 + H2O reaction system is studied, the parameters of the activation of COOH group accumulation are found (where PVA is a polyvinyl alcohol). New data on the effect process conditions (length of oxidation, temperature, and hydrogen peroxide concentration) have on the degree of destructive transformations of polyvinyl alcohol in the investigated reaction system are obtained.

  10. Intensification process of air-hydrogen mixture burning in the variable cross section channel by means of the air jet

    Science.gov (United States)

    Zamuraev, V. P.; Kalinina, A. P.

    2018-03-01

    The paper presents the results of numerical modeling of a transonic region formation in the flat channel. Hydrogen flows into the channel through the holes in the wall. The jet of compressed air is localized downstream the holes. The transonic region formation is formed by the burning of heterogeneous hydrogen-air mixture. It was considered in the framework of the simplified chemical kinetics. The interesting feature of the regime obtained is the following: the distribution of the Mach numbers is qualitatively similar to the case of pulse-periodic energy sources. This mode is a favorable prerequisite for the effective fuel combustion in the expanding part of the channel when injecting fuel into this part.

  11. Interactions of Plutonium Dioxide with Water and Oxygen-Hydrogen Mixtures

    International Nuclear Information System (INIS)

    Haschke, J.M.; Allen, T.H.

    1999-01-01

    Pressure-volume-temperature data and mass spectrometric results obtained during exposure of PuO 2 to D 2 O show that the dioxide reacts with water at room temperature to produce a higher oxide (PuO 2+x )and H 2 . Results demonstrate that PuO 2+x is the thermodynamically stable oxide in air. The absence of O 2 at detectable levels in the gas phase implies that radiolytic decomposition of water to the elements is not a significant reaction. The rate of the PuO 2 +H 2 O reaction is 6±4 nmol H 2 /m 2 day, a value that is independent of the H 2 O concentration on the oxide over a range that extends from fractional monolayer coverage to saturation by liquid water. Evaluation of literature data shows that oxide compositions in excess of PuO 2.25 are attained, but the maximum value of x is unknown. During exposure of PuO 2 to a 2:1 D 2 :O 2 mixture at room temperature, the elements combine by a process consistent with a surface-catalyzed reaction. Water is simultaneously formed by the H 2 +O 2 reaction and consumed by the PuO 2 + H 2 O reaction and accumulates until the opposing rates are equal. Thereafter, PuO 2+x is formed at a constant rate by the water-catalyzed PuO 2 + O 2 reaction. The failure of earlier attempts to prepare higher oxides of plutonium is discussed and the catalytic cycle that promotes the reaction of PuO 2 with O 2 is described. Implications of the results for extended storage and environmental chemistry of oxide are examined. Moisture-catalyzed oxidation of PuO 2 accounts for observation of both pressure increases and decreases in oxide storage containers with air atmospheres. Application of the experimental rate results indicates that the reaction of a typical oxide with 0.5 mass % of adsorbed water maybe complete after 25 to 50 years at room temperature

  12. Reactions of plutonium dioxide with water and oxygen-hydrogen mixtures: Mechanisms for corrosion of uranium and plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Haschke, John M.; Allen, Thomas H.; Morales, Luis A.

    1999-06-18

    Investigation of the interactions of plutonium dioxide with water vapor and with an oxygen-hydrogen mixture show that the oxide is both chemically reactive and catalytically active. Correspondence of the chemical behavior with that for oxidation of uranium in moist air suggests that similar catalytic processes participate in the mechanism of moisture-enhanced corrosion of uranium and plutonium. Evaluation of chemical and kinetic data for corrosion of the metals leads to a comprehensive mechanism for corrosion in dry air, water vapor, and moist air. Results are applied in confirming that the corrosion rate of Pu in water vapor decreases sharply between 100 and 200 degrees C.

  13. Process for the separation of deuterium and tritium from water using ammonia and a hydrogen-nitrogen-mixture

    International Nuclear Information System (INIS)

    Mandrin, Ch.

    1986-01-01

    A multistage process for separation of deuterium and tritium from water using ammonia and a hydrogen-nitrogen mixture. In a first stage isotopic exchange takes place between water containing deuterium and tritium, and ammonia depleted in deuterium and tritium. The molar ammonia throughput is chosen to be greater than two third of the molar throughput of water. The advantage of the process consists in the fact that the main product is water almost entirely free from deuterium and tritium. The byproducts are compounds enriched in deuterium and tritium, and nitrogen enriched in N-15

  14. Selective hydrogen atom abstraction by hydrogen atoms in photolysis of cyclohexane-normal pentane mixtures at 77 K

    International Nuclear Information System (INIS)

    Miyazaky, T.; Guedes, S.M.L.; Andrade e Silva, L.G. de; Fernandes, L.

    1977-01-01

    The reaction of H atoms, produced by the photolysis of HI, has been studied in c-C 6 H 12 -n-C 5 H 12 mixtures at 77K. H atoms in c-C 6 H 12 matrix react more effectively with solute n-C 5 H 12 than solvent c-C 6 H 12 , while H atoms in n-C 5 H 12 matrix react more effectively with solute c-C 6 H 12 than solvent n-C 5 H 12 [pt

  15. PERFORMANCE EVALUATION OF EXTERNAL MIXTURE FORMATION STRATEGY IN HYDROGEN-FUELED ENGINE

    OpenAIRE

    Mohammed Kamil; M. M. Rahman; Rosli A. Bakar

    2011-01-01

    Mohammed Kamil1, M. M. Rahman2 and Rosli A. Bakar2Hydrogen induction strategy in an internal combustion engine plays a vital role in increasing the power density and prohibiting combustion anomalies. This paper inspects the performance characteristics of cylinder hydrogen-fueled engine with port injection feeding strategy. To that end, a one-dimensional gas dynamic model has been built to represent the flow and heat transfer in the components of the engine. The governing equations are introdu...

  16. A combined experimental and theoretical approach to the study of hydrogen bond interaction in the binary mixture of N-methylimidazole with water

    International Nuclear Information System (INIS)

    Huang, Rongyi; Du, Rongbin; Liu, Guangxiang; Zhao, Xiuqin; Ye, Shiyong; Wu, Genhua

    2012-01-01

    Highlights: ► Densities of N-methylimidazole with water binary mixture were measured. ► Excess molar volumes were fitted to Redlich–Kister polynomial equation. ► Excess molar volumes are negative in the whole mole fraction range. ► 1:1 Hydrogen complex formation between the unlike components was observed. ► Formation of hydrogen bonds in the binary mixture was confirmed by DFT//B3LYP. - Abstract: The intermolecular hydrogen bond interactions in the N-methylimidazole (MeIm) with water binary mixture have been studied by a combined experimental and theoretical approach. The densities of the binary mixture have been measured at T = (288.15 to 323.15) K and at atmospheric pressure. From the experimental data, excess molar volumes were determined as a function of composition at each temperature. The results reveal the formation of 1:1 hydrogen bond complex between MeIm with water at the maximal excess molar volume. Meanwhile, the formation of hydrogen bonds in the binary mixture was further confirmed by high level theoretical calculation. The structures, interactional energies and bond characteristics of the hydrogen bond complexes were calculated in the gas phase using density functional theory (DFT) at the B3LYP/6-311++G(d, p) theory levels. The changes of thermodynamic properties from the monomers to hydrogen bond complexes with the temperature ranging from (288.15 to 323.15) K were obtained using the statistical thermodynamic method. Thermodynamic analyses have been interpreted in terms of intermolecular interactions and excess molar volume changes in the binary mixture. It was also found that the formation reaction of the hydrogen bond complex of MeIm with water was an exothermic, entropy reduced and spontaneous thermodynamic process at all the temperature studied.

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

    International Nuclear Information System (INIS)

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

    1997-11-01

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

  18. Quantitative separation of the influence of hydrogen bonding of ethanol/water mixture on the shape recovery behavior of polyurethane shape memory polymer

    International Nuclear Information System (INIS)

    Lu, Haibao; Leng, Jinsong; Min Huang, Wei; Fu, Y Q

    2014-01-01

    A thermally responsive polyurethane shape memory polymer (SMP) can be actuated in water through a hydrogen bonding interaction between water and the SMP. In this work, we present a comprehensive approach to quantify the hydrogen bonding on the shape recovery behavior of a polyurethane SMP. The stimuli response to the hydrogen bonding of the polyurethane SMP was investigated in ethanol/water mixtures by varying the water content. It was found that depending on the water content, the SMP features a critical hydrogen bonding strength associated with its shape recovery behavior. The Hildebrand solubility parameter theory was employed to quantitatively identify and separate the hydrogen bonding effect of the ethanol/water mixture on the shape recovery ratio and the time. Furthermore, a phenomenological model was developed to predict the glass transition temperature and the shape recovery time of a polyurethane SMP and was verified by the available experimental results. (paper)

  19. Communication: A novel method for generating molecular mixtures at extreme conditions: The case of hydrogen and oxygen

    International Nuclear Information System (INIS)

    Pravica, Michael; Sneed, Daniel; White, Melanie; Wang, Yonggang

    2014-01-01

    We have successfully created a segregated mixture of hydrogen and oxygen at high pressure in a diamond anvil cell using hard x-ray photochemistry. A keyhole (two holes connected by an opening) sample chamber was created in a metallic gasket to support two segregated powders of ammonia borane and potassium perchlorate, respectively, in each hole at a pressure of ∼5.0 GPa. Both holes were separately irradiated with synchrotron hard x-rays to release molecular oxygen and molecular hydrogen, respectively. Upon irradiation of the first KClO 4 -containing hole, solid reddish-orange O 2 appeared in the region of irradiation and molecular oxygen was found to diffuse throughout the entire sample region. The second ammonia borane-containing hole was then irradiated and H 2 was observed to form via Raman spectroscopy. Water also was observed in the ammonia borane-containing hole and possibly (in the form of ice VII) in the second hole. This unique experiment demonstrates the ability to easily create solid mixtures of simple molecular systems via x-ray irradiation and then react them via further irradiation which will aid the study of chemistry under extreme conditions

  20. Analysis of Water Hammer with Different Closing Valve Laws on Transient Flow of Hydrogen-Natural Gas Mixture

    Directory of Open Access Journals (Sweden)

    Norazlina Subani

    2015-01-01

    Full Text Available Water hammer on transient flow of hydrogen-natural gas mixture in a horizontal pipeline is analysed to determine the relationship between pressure waves and different modes of closing and opening of valves. Four types of laws applicable to closing valve, namely, instantaneous, linear, concave, and convex laws, are considered. These closure laws describe the speed variation of the hydrogen-natural gas mixture as the valve is closing. The numerical solution is obtained using the reduced order modelling technique. The results show that changes in the pressure wave profile and amplitude depend on the type of closing laws, valve closure times, and the number of polygonal segments in the closing function. The pressure wave profile varies from square to triangular and trapezoidal shape depending on the type of closing laws, while the amplitude of pressure waves reduces as the closing time is reduced and the numbers of polygonal segments are increased. The instantaneous and convex closing laws give rise to minimum and maximum pressure, respectively.

  1. Effectiveness of thermal ignition devices in lean hydrogen-air-steam mixtures

    International Nuclear Information System (INIS)

    Tamm, H.; McFarlane, R.; Liu, D.D.S.

    1985-03-01

    Deliberate ignition of hydrogen at low concentrations in reactor containment systems is one method of controlling hydrogen during degraded core accidents. Since many postulated accident conditions have substantial amounts of steam present, experiments have been performed to determine the hydrogen-air-steam concentration regimes in which ignitors would be effective. In these experiments, both a GM AC 7G thermal flow plug and a Tayco Model 3442 ignitor have been used. These ignitors have been installed in PWR containments with ice condensers and in BWR Mark III containments. This report presents the results of these ignitor effectiveness experiments, and gives the ignition limits and the effect of steam on the ignitor surface temperatures required for ignition

  2. Dielectric relaxation and hydrogen bonding interaction in xylitol-water mixtures using time domain reflectometry

    Science.gov (United States)

    Rander, D. N.; Joshi, Y. S.; Kanse, K. S.; Kumbharkhane, A. C.

    2016-01-01

    The measurements of complex dielectric permittivity of xylitol-water mixtures have been carried out in the frequency range of 10 MHz-30 GHz using a time domain reflectometry technique. Measurements have been done at six temperatures from 0 to 25 °C and at different weight fractions of xylitol (0 xylitol-water can be well described by Cole-Davidson model having an asymmetric distribution of relaxation times. The dielectric parameters such as static dielectric constant and relaxation time for the mixtures have been evaluated. The molecular interaction between xylitol and water molecules is discussed using the Kirkwood correlation factor ( g eff ) and thermodynamic parameter.

  3. Modes of reaction front propagation and end-gas combustion of hydrogen/air mixtures in a closed chamber

    KAUST Repository

    Shi, Xian

    2017-01-05

    Modes of reaction front propagation and end-gas combustion of hydrogen/air mixtures in a closed chamber are numerically investigated using an 1-D unsteady, shock-capturing, compressible and reacting flow solver. Different combinations of reaction front propagation and end-gas combustion modes are observed, i.e., 1) deflagration without end-gas combustion, 2) deflagration to end-gas autoignition, 3) deflagration to end-gas detonation, 4) developing or developed detonation, occurring in the sequence of increasing initial temperatures. Effects of ignition location and chamber size are evaluated: the asymmetric ignition is found to promote the reactivity of unburnt mixture compared to ignitions at center/wall, due to additional heating from asymmetric pressure waves. End-gas combustion occurs earlier in smaller chambers, where end-gas temperature rise due to compression heating from the deflagration is faster. According to the ξ−ε regime diagram based on Zeldovich theory, modes of reaction front propagation are primarily determined by reactivity gradients introduced by initial ignition, while modes of end-gas combustion are influenced by the total amount of unburnt mixture at the time when autoignition occurs. A transient reactivity gradient method is provided and able to capture the occurrence of detonation.

  4. Modes of reaction front propagation and end-gas combustion of hydrogen/air mixtures in a closed chamber

    KAUST Repository

    Shi, Xian; Ryu, Je Ir; Chen, Jyh-Yuan; Dibble, Robert W.

    2017-01-01

    Modes of reaction front propagation and end-gas combustion of hydrogen/air mixtures in a closed chamber are numerically investigated using an 1-D unsteady, shock-capturing, compressible and reacting flow solver. Different combinations of reaction front propagation and end-gas combustion modes are observed, i.e., 1) deflagration without end-gas combustion, 2) deflagration to end-gas autoignition, 3) deflagration to end-gas detonation, 4) developing or developed detonation, occurring in the sequence of increasing initial temperatures. Effects of ignition location and chamber size are evaluated: the asymmetric ignition is found to promote the reactivity of unburnt mixture compared to ignitions at center/wall, due to additional heating from asymmetric pressure waves. End-gas combustion occurs earlier in smaller chambers, where end-gas temperature rise due to compression heating from the deflagration is faster. According to the ξ−ε regime diagram based on Zeldovich theory, modes of reaction front propagation are primarily determined by reactivity gradients introduced by initial ignition, while modes of end-gas combustion are influenced by the total amount of unburnt mixture at the time when autoignition occurs. A transient reactivity gradient method is provided and able to capture the occurrence of detonation.

  5. Theory of vibrational relaxation in mixtures of ortho- and para-hydrogen

    International Nuclear Information System (INIS)

    Moise, A.; Pritchard, H.O.

    1981-01-01

    A numerical study of the vibrational relaxation at 500 K of a mixture of ortho-H 2 and para-H 2 is described. The required state-to-state rate constants were calculated and missing pieces of data were estimated by interpolation. It is concluded that only one relaxation time will be observed in any mixture of orth-H 2 and para-H 2 and that (except at very high dilutions in a third inert gas) the relaxation rate constant will be close to the mean of the individual rate constants for relaxation, weighted according to the respective mole fractions of ortho-H 2 and para-H 2 present in the mixture. The relaxation process can be modelled as an electrical RC network, whose time constants can be written down as sums of the appropriate microscopic rate constants. By using this model the conditions required for a mixture of two gases to exhibit two distinct vibrational relaxation times can be explored

  6. PERFORMANCE EVALUATION OF EXTERNAL MIXTURE FORMATION STRATEGY IN HYDROGEN-FUELED ENGINE

    Directory of Open Access Journals (Sweden)

    Mohammed Kamil

    2011-12-01

    Full Text Available Mohammed Kamil1, M. M. Rahman2 and Rosli A. Bakar2Hydrogen induction strategy in an internal combustion engine plays a vital role in increasing the power density and prohibiting combustion anomalies. This paper inspects the performance characteristics of cylinder hydrogen-fueled engine with port injection feeding strategy. To that end, a one-dimensional gas dynamic model has been built to represent the flow and heat transfer in the components of the engine. The governing equations are introduced followed by the performance parameters and model description. Air-fuel ratio was varied from a stoichiometric limit to a lean limit. The rotational speed of the engine was also changed from 1000 to 4500 RPM. The injector location was fixed in the mid-point of the intake port. The general behavior of the hydrogen engine was similar to that of a gasoline engine, apart from a reduction in the power density, which was due to a decrease in the volumetric efficiency. This emphasizes the ability of retrofitting traditional engines for hydrogen fuel with minor modifications. The decrease in the volumetric efficiency needs to be rectified.

  7. Povidone-iodine and hydrogen peroxide mixture soaked gauze pack: a novel hemostatic technique

    NARCIS (Netherlands)

    Arakeri, G.; Brennan, P.A.

    2013-01-01

    Persistent oozing of blood is a common occurrence in maxillofacial surgery, and occasionally it hampers visibility and delays or even prevents continuation of the procedure. This report describes a novel method of controlling blood ooze using swabs soaked with povidone-iodine and hydrogen peroxide

  8. Radiation-induced chemical reactions of carbon monoxide and hydrogen mixture

    International Nuclear Information System (INIS)

    Sugimoto, S.; Nishii, M.; Sugiura, T.

    1984-01-01

    The radiation chemical reaction of CO-H 2 mixture has been studied in the pressure range from 10 4 to 1.3 x 10 5 Pa using 7 l. reaction vessel made of stainless steel. Various hydrocarbons and oxygen containing compounds such as methane, formaldehyde, acetaldehyde, and methanol have been obtained as radiolytic products. The amounts and the G values of these products depended upon the irradiation conditions such as composition of reactant, total pressure, reaction temperature, and dose. It was found that the irradiation at low dose produced small amounts of trioxane and tetraoxane, which have not yet been reported in literature. The yields of these cyclic ethers increased at high pressure and at low temperature. An experiment was also made on CO-H 2 mixture containing ammonia as a cation scavenger to investigate the precursor of these products. (author)

  9. Irradiation effect on the reaction of mixture of carbon monoxide and hydrogen, (3)

    International Nuclear Information System (INIS)

    Sugimoto, Shun-ichi; Nishii, Masanobu

    1983-08-01

    A series of our studies on radiation chemical reaction of CO and H 2 mixture indicated that several organic compounds were produced by electron beam irradiation and the amounts of the products increased with increasing pressure and also increased when the irradiation was carried out under circulation. The present study was carried out in an attempt to investigate whether the amounts of the products increase when the mixture is irradiated under circulation at elevated pressure. For this purpose, a reaction apparatus, which can irradiated the mixture up to 10,000 Torr under circulation, was built and the experiments were carried out on the amounts of products as functions of pressure, irradiation time, gas composition, temperature and dose rate. G values of most compounds were found to increased with increasing pressure under circulation. Among the products, the reaction conditions giving high yield of acetaldehyde were studied in detail, since this compound is considered to be one of the most important intermediate compounds in C 1 chemistry. The maximum G value of acetaldehyde was 2.9 which was obtained at 8,000 Torr, 55 CO mol%, 2 x 10 19 eV.g -1 .sec -1 , 1.3 x 10 20 eV.g -1 and 22 0 C. The selectivity favored this compounds in all organic compounds was 57 mol% at the conversion rate of 0.8 %. In order to elucidate the reaction paths of formation and disappearance of acetaldehyde, the amounts of products were determined for the mixture with or without the presence of small amounts of acetadehyde. The results indicate that acetaldehyde formed by irradiation from

  10. Hydrophobic catalyst mixture for the isotopic exchange reaction between hydrogen and water

    Energy Technology Data Exchange (ETDEWEB)

    Paek, S.; Ahn, D. H.; Choi, H. J.; Kim, K. R.; Lee, M.; Yim, S. P.; Chung, H. [KAERI, Taejon (Korea, Republic of)

    2005-11-15

    Pt/SDBC catalyst, which is used for the hydrogen-water isotopic exchange reaction, was prepared. The various properties of the catalyst, such as the thermal stability, pore structure and the platinum dispersion, were investigated. A hydrophobic Pt/SDBC catalyst which has been developed for the LPCE column of the WTRF (Wolsong Tritium Removal Facility) was tested in a trickle bed reactor. An experimental apparatus was built for the test of the catalyst at various temperatures and gas velocities.

  11. Hydrophobic catalyst mixture for the isotopic exchange reaction between hydrogen and water

    International Nuclear Information System (INIS)

    Paek, S.; Ahn, D. H.; Choi, H. J.; Kim, K. R.; Lee, M.; Yim, S. P.; Chung, H.

    2005-01-01

    Pt/SDBC catalyst, which is used for the hydrogen-water isotopic exchange reaction, was prepared. The various properties of the catalyst, such as the thermal stability, pore structure and the platinum dispersion, were investigated. A hydrophobic Pt/SDBC catalyst which has been developed for the LPCE column of the WTRF (Wolsong Tritium Removal Facility) was tested in a trickle bed reactor. An experimental apparatus was built for the test of the catalyst at various temperatures and gas velocities

  12. Physical Properties of Hydrogenated Dimers of Norbornadiene and Exo-Tetrahydrodicyclopentadiene and their Mixtures

    Science.gov (United States)

    1977-12-01

    structures of these com- pounds are shown in Fig. 1, along with the abbreviations (HXX, XTHDCPD , etc.) by which they will be referred to in the...crystal because of the difficulty in obtaining good DSC data at the very low temperatures below the XTHDCPD melting point. The four NBD hydrogenated...estimated from the DSC fusion curve, was used for ACpf for XTHDCPD . The results of these calculations are shown in Fig. 3 as plots of Ti (in K and *F) versus

  13. Povidone-iodine and hydrogen peroxide mixture soaked gauze pack: a novel hemostatic technique.

    Science.gov (United States)

    Arakeri, Gururaj; Brennan, Peter A

    2013-11-01

    Persistent oozing of blood is a common occurrence in maxillofacial surgery, and occasionally it hampers visibility and delays or even prevents continuation of the procedure. This report describes a novel method of controlling blood ooze using swabs soaked with povidone-iodine and hydrogen peroxide (PI-HP pack) that is particularly useful in relatively inaccessible areas of the maxillofacial region. Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  14. Doppler spectroscopy of hydrogen Balmer lines in a hollow cathode glow discharge in ammonia and argon-ammonia mixture

    International Nuclear Information System (INIS)

    Sisovic, N. M.; Konjevic, N.

    2008-01-01

    The results of Doppler spectroscopy of hydrogen Balmer lines from a stainless steel (SS) and copper (Cu) hollow cathode (HC) glow discharge in ammonia and argon-ammonia mixture are reported. The experimental profiles in ammonia discharge are fitted well by superposing three Gaussian profiles. The half widths, in energy units, of narrow and medium Gaussians are in the ranges 0.3-0.4 eV and 3-4 eV, respectively, for both hollow cathodes what is expected on the basis of earlier electron beam→NH 3 experiments. The half widths of the largest Gaussian in ammonia are 46 and 55 eV for SS and Cu HC, respectively. In argon-ammonia discharge, three Gaussians are also required to fit experimental profiles. While half widths of narrow and medium Gaussians are similar to those in ammonia, the half widths of the largest Gaussians are 35 and 42 eV for SS and Cu HC, respectively. The half widths of the largest Gaussians in ammonia and in argon-ammonia mixture indicate the presence of excessive Doppler broadening.

  15. Characteristics of autoignited laminar lifted flames in heated coflow jets of carbon monoxide/hydrogen mixtures

    KAUST Repository

    Choi, Byungchul

    2012-06-01

    The characteristics of autoignited lifted flames in laminar jets of carbon monoxide/hydrogen fuels have been investigated experimentally in heated coflow air. In result, as the jet velocity increased, the blowoff was directly occurred from the nozzle-attached flame without experiencing a stabilized lifted flame, in the non-autoignited regime. In the autoignited regime, the autoignited lifted flame of carbon monoxide diluted by nitrogen was affected by the water vapor content in the compressed air oxidizer, as evidenced by the variation of the ignition delay time estimated by numerical calculation. In particular, in the autoignition regime at low temperatures with added hydrogen, the liftoff height of the autoignited lifted flames decreased and then increased as the jet velocity increased. Based on the mechanism in which the autoignited laminar lifted flame is stabilized by ignition delay time, the liftoff height can be influenced not only by the heat loss, but also by the preferential diffusion between momentum and mass diffusion in fuel jets during the autoignition process. © 2012 The Korean Society of Mechanical Engineers.

  16. Cryopumping of deuterium hydrogen and helium mixtures on smooth 4.2 K surfaces

    International Nuclear Information System (INIS)

    Chou, T.S.; Halama, H.J.

    1977-01-01

    The large quantities of deuterium and hydrogen to be pumped in a fusion reactor and its subsystems favor cryopumping over other pumping methods. Cryogen consumption and the operating pressure will not only depend on the gas to be pumped, but also on the amount of helium gas present in the system. In fact, residual helium pressure between pulses will determine the power dissipation of the pump, and hence, influence the choice of cryocondensation or cryosorption. In this paper we will present the results of our studies on (1) cryotrapping of helium in thick D 2 and H 2 films and hydrogen in D 2 films at 4.2 K; (2) diffusion of He and H 2 from D 2 films; (3) steady-state liquid helium consumption; (4) liquid helium consumption as a function of D 2 and H 2 fluxes being pumped; (5) liquid helium consumption as a function of He partial pressure in the system. Finally, these measurements will suggest maximum permissible He to D 2 and He to H 2 ratios in a cryocondensation pump

  17. Transport coefficients for carbon, hydrogen, and the organic mixture C2H3

    International Nuclear Information System (INIS)

    Rinker, G.

    1986-02-01

    Electrical and thermal transport coefficients are calculated for amorphous elemental carbon and hydrogen, using the best available systematic theoretical methods. The density range considered is 10 -3 g/cm 3 less than or equal to rho less than or equal to 10 6 g/cm 3 for carbon, and 10 -4 g/cm 3 less than or equal to rho less than or equal to 10 5 g/cm 3 for hydrogen. The temperature range considered is 10 -2 eV less than or equal to kT less than or equal to 10 4 eV. Calculational methods include relativistic partial-wave analysis of the extended Ziman theory, and nonrelativistic plane-wave analysis (Born approximation) of the original Ziman theory. Physical models include relativistic Dirac-Fock-Slater and nonrelativistic Thomas-Fermi-Dirac electron-ion potentials, and one-component-plasma ion-ion structure factors. A mixing algorithm is used to obtain approximate transport coefficients for the atomic ratio C 2 H 3 . 10 refs., 31 figs

  18. Laminar burning velocity and Markstein length of nitrogen diluted natural gas/hydrogen/air mixtures at normal, reduced and elevated pressures

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Haiyan [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Eng., Xi' an Jiaotong University (China); Institute of High Performance Computing, A-star (Singapore); Ji, Min; Jiao, Qi; Huang, Qian; Huang, Zuohua [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Eng., Xi' an Jiaotong University (China)

    2009-04-15

    Flame propagation of premixed nitrogen diluted natural gas/hydrogen/air mixtures was studied in a constant volume combustion bomb under various initial pressures. Laminar burning velocities and Markstein lengths were obtained for the diluted stoichiometric fuel/air mixtures with different hydrogen fractions and diluent ratios under various initial pressures. The results showed that both unstretched flame speed and unstretched burning velocity are reduced with the increase in initial pressure (except when the hydrogen fraction is 80%) as well as diluent ratio. The velocity reduction rate due to diluent addition is determined mainly by hydrogen fraction and diluent ratio, and the effect of initial pressure is negligible. Flame stability was studied by analyzing Markstein length. It was found that the increase of initial pressure and hydrogen fraction decreases flame stability and the flame tends to be more stable with the addition of diluent gas. Generally speaking, Markstein length of a fuel with low hydrogen fraction is more sensitive to the change of initial pressure than that of a one with high hydrogen fraction. (author)

  19. INVESTIGATION OF COMBUSTION, PERFORMANCE AND EMISSION CHARACTERISTICS OF SPARK IGNITION ENGINE FUELLED WITH BUTHANOL – GASOLINE MIXTURE AND A HYDROGEN ENRICHED AIR

    Directory of Open Access Journals (Sweden)

    Alfredas Rimkus

    2016-09-01

    Full Text Available In this study, spark ignition engine fuelled with buthanol-gasoline mixture and a hydrogen-enriched air was investigated. Engine performance, emissions and combustion characteristics were investigated with different buthanol (10% and 20% by volume gasoline mixtures and additionally supplied oxygen and hydrogen (HHO gas mixture (3.6 l/min in the sucked air. Hydrogen, which is in the HHO gas, improves gasoline and gasoline-buthanol mixture combustion, increases indicated pressure during combustion phase and decreases effective specific fuel consumption. Buthanol addition decreases the rate of heat release, the combustion temperature and pressure are lower which have an influence on lower nitrous oxide (NOx emission in exhaust gases. Buthanol lowers hydrocarbon (HC formation, but it increases carbon monoxide (CO concentration and fuel consumption. Combustion process analysis was carried out using AVL BOOST software. Experimental research and combustion process numerical simulation showed that using balanced buthanol and hydrogen addition, optimal efficient and ecological parameters could be achieved when engine is working with optimal spark timing, as it would work on gasoline fuel.

  20. Fuel cells and hydrogen : implications for the future automobile

    International Nuclear Information System (INIS)

    Frise, P.R.

    2006-01-01

    The generation, storage, transportation, distribution and dispensing of hydrogen has clearly emerged as the central issue in the global move toward a carbon-free fuel future for the mobility industry. The technical, economic and societal issues surrounding the provision of fuels for fuel cells appear to be at least as daunting, if not more, than any other issue. Nonetheless, automakers from all over the world are pressing ahead with their extensive research and development programs and these have showed great promise in addressing the key on-vehicle issues such as durability, cold starting and packaging. More work remains on several key problems and the presentation will elucidate these and endeavor to point the way to solutions as seen from an automotive engineering viewpoint. (author)

  1. H2-H2O-HI Hydrogen Separation in H2-H2O-HI Gaseous Mixture Using the Silica Membrane

    International Nuclear Information System (INIS)

    Pandiangan, Tumpal

    2002-01-01

    It was evaluated aiming at the application for hydrogen iodide decomposition in the thermochemical lS process. Porous alumina tube having pore size of 0.1 μm was modified by chemical vapor deposition using tetraethoxysilane. The permeance single gas of He, H 2 , and N 2 was measured at 300-600 o C. Hydrogen permeance of the modified membrane at a permeation temperature of 600 o C was about 5.22 x 10 -08 mol/Pa m 2 s, and 3.2 x 10 -09 of using gas mixture of H 2 -H 2 O-HI, where as HI permeances was below 1 x 10 -10 mol/Pa m 2 s. The Hydrogen permeance relative was not changed after 25 hours exposure in a mixture of H 2 -H 2 O-HI gas at the temperature of 450 o C. (author)

  2. Membrane separation study for methane-hydrogen gas mixtures by molecular simulations

    Directory of Open Access Journals (Sweden)

    T. Kovács

    2017-06-01

    Full Text Available Direct simulation results for stationary gas transport through pure silica zeolite membranes (MFI, LTA and DDR types are presented using a hybrid, non-equilibrium molecular dynamics simulation methodology introduced recently. The intermolecular potential models for the investigated CH_4 and H_2 gases were taken from literature. For different zeolites, the same atomic (Si and O interaction parameters were used, and the membranes were constructed according to their real (MFI, LTA, or DDR crystal structures. A realistic nature of the applied potential parameters was tested by performing equilibrium adsorption simulations and by comparing the calculated results with the data of experimental adsorption isotherms. The results of transport simulations carried out at 25°C and 125°C, and at 2.5, 5 or 10 bar clearly show that the permeation selectivities of CH_4 are higher than the corresponding permeability ratios of pure components, and significantly differ from the equilibrium selectivities in mixture adsorptions. We experienced a transport selectivity in favor of CH_4 in only one case. A large discrepancy between different types of selectivity data can be attributed to dissimilar mobilities of the components in a membrane, their dependence on the loading of a membrane, and the unlike adsorption preferences of the gas molecules.

  3. Method of extracting iodine from liquid mixtures of iodine, water and hydrogen iodide

    Science.gov (United States)

    Mysels, Karol J.

    1979-01-01

    The components of a liquid mixture consisting essentially of HI, water and at least about 50 w/o iodine are separated in a countercurrent extraction zone by treating with phosphoric acid containing at least about 90 w/o H.sub.3 PO.sub.4. The bottom stream from the extraction zone is substantially completely molten iodine, and the overhead stream contains water, HI, H.sub.3 PO.sub.4 and a small fraction of the amount of original iodine. When the water and HI are present in near-azeotropic proportions, there is particular advantage in feeding the overhead stream to an extractive distillation zone wherein it is treated with additional concentrated phosphoric acid to create an anhydrous HI vapor stream and bottoms which contain at least about 85 w/o H.sub.3 PO.sub.4. Concentration of these bottoms provides phosphoric acid infeed for both the countercurrent extraction zone and for the extractive distillation zone.

  4. Collision-Induced Infrared Absorption by Hydrogen-Helium gas mixtures at Thousands of Kelvin

    Science.gov (United States)

    Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

    2010-10-01

    The interaction-induced absorption by collisional pairs of H2 molecules is an important opacity source in the atmospheres of the outer planets and cool stars ^[1]. The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H2--H2, H2--He, and H2--H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin ^[2]. Laboratory measurements of interaction-induced absorption spectra by H2 pairs exist only at room temperature and below. We show that our results reproduce these measurements closely ^[2], so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures ^[2]. [1] L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 [2] Xiaoping Li, Katharine L. C. Hunt, Fei Wang, Martin Abel, and Lothar Frommhold, ``Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin'', International Journal of Spectroscopy, vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201

  5. Burning rates of hydrogen-air mixtures in containment buildings and the consequent pressure transients

    International Nuclear Information System (INIS)

    Tennankore, K.N.; Kumar, R.K.; Razzaghi, M.

    1987-01-01

    One-dimensional flame models are often used to predict the pressure transients caused by hydrogen combustion in containments during postulated severe accidents. In the absence of data, these models account for prevailing flame acceleration mechanisms, such as initial turbulence, venting and obstacle-induced turbulence, by using arbitrarily large burning velocities that are much higher than laminar burning velocities. Using an intermediate-scale test facility at the Whiteshell Nuclear Research Establishment we have obtained necessary data on the effects of flame acceleration mechanisms, to estimate the safety margin in the buring velocities used in the models. So far, data have been analyzed, with a one-dimensional model, to determine effective burning velocities and burning-rate enhancement factors. The results of the analyses indicate that the effect of initial turbulence on the burning rate can be bounded only if the effect of flame-generated turbulence is included. The effect of venting can be accounted for by using two burning velocities, one for the pre-vent duration and a second increased value during the vented-combustion stage. The enhancement factors due to these two mechanisms, for the different conditions analyzed, varied up to 5.4, and the effective burning velocities varied up to 8.4 m/s

  6. Vapour pressure and excess Gibbs free energy of binary mixtures of hydrogen sulphide with ethane, propane, and n-butane at temperature of 182.33K

    International Nuclear Information System (INIS)

    Lobo, L.Q.; Ferreira, A.G.M.; Fonseca, I.M.A.; Senra, A.M.P.

    2006-01-01

    The vapour pressure of binary mixtures of hydrogen sulphide with ethane, propane, and n-butane was measured at T=182.33K covering most of the composition range. The excess Gibbs free energy of these mixtures has been derived from the measurements made. For the equimolar mixtures G m E (x 1 =0.5)=(835.5+/-5.8)J.mol -1 for (H 2 S+C 2 H 6 ) (820.1+/-2.4)J.mol -1 for (H 2 S+C 3 H 8 ), and (818.6+/-0.9)J.mol -1 for (H 2 S+n-C 4 H 10 ). The binary mixtures of H 2 S with ethane and with propane exhibit azeotropes, but that with n-butane does not

  7. Surface kinetics for catalytic combustion of hydrogen-air mixtures on platinum at atmospheric pressure in stagnation flows

    Science.gov (United States)

    Ikeda, H.; Sato, J.; Williams, F. A.

    1995-03-01

    Experimental studies of the combustion of premixed hydrogen-air mixtures impinging on the surface of a heated platinum plate at normal atmospheric pressure were performed and employed to draw inferences concerning surface reaction mechanisms and rate parameters applicable under practical conditions of catalytic combustion. Plate and gas temperatures were measured by thermocouples, and concentration profiles of major stable species in the gas were measured by gas-chromatographic analyses of samples withdrawn by quartz probes. In addition, ignition and extinction phenomena were recorded and interpreted with the aid of a heat balance at the surface and a previous flow-field analysis of the stagnation-point boundary layer. From the experimental and theoretical results, conclusions were drawn concerning the surface chemical-kinetic mechanisms and values of the elementary rate parameters that are consistent with the observations. In particular, the activation energy for the surface oxidation step H + OH → H 2O is found to be appreciably less at these high surface coverages than in the low-coverage limit.

  8. A state of the art report on flame acceleration and transition to detonation in hydrogen/air/diluent mixtures

    International Nuclear Information System (INIS)

    Chan, C.K.; Tennankore, K.N.

    1991-12-01

    Accidental ignition in pockets of flammable hydrogen/air/diluent mixtures will lead to a deflagration wave (slow flame). Particular conditions can accelerate this flame and cause a transition from deflagration to a detonation wave (rapid flame), with its associated spatially non-uniform and very high pressures. In this report, the differences between deflagration and detonation are outlined, and the various flame acceleration mechanisms, along with the related research results, are reviewed. The current understanding of transition to detonation as a two-step process, a local explosion followed by an amplification of the resulting blast wave into a detonation wave, is described in detail. Occurrence of a local explosion in hot spots generated by the focussing of shock waves existing ahead of a fast flame, or in high-reactivity centres generated by turbulence-induced rapid mixing of flame and unburnt gas, and the resulting local quenching of the flame, are described and relevant publications are cited. The current models for flame acceleration are listed and their limitations are identified. Also, the available qualitative criteria for assessing the likelihood of transition to detonation under given conditions are briefly discussed. The feasibility of developing a quantitative methodology for assessing this likelihood is discussed, and further more work required to complete this development is outlined. The development of a quantitative methodology is recommended

  9. Analysis of hydrogen-deuterium mixtures and of mixtures of heavy-water and light-water by means of a mass spectrometer; Analyse des melanges hydrogene-deuterium et des melanges d'eau lourde et d'eau legere au moyen du spectrometre de masse

    Energy Technology Data Exchange (ETDEWEB)

    Chenouard, J; Gueron, J; Roth, E

    1951-07-01

    The differences between hydrogen and deuterium with respect to the capture of thermal neutrons (hydrogen = 0.31 barn; deuterium 0.00065 barn) explains the interest of detecting small variations of the isotopic composition of the heavy waters used in the Chatillon nuclear pile. The aim of this report is to describe and discuss the method used since more than a year for the dosimetry of heavy waters. After a recall of the principle of mass spectroscopy analysis of deuterium-hydrogen mixtures, the preciseness of the results is presented and the balancing method used for the determination of the isotopic composition of hydrogen-deuterium mixtures is explained in detail. Finally, a brief comparison of the preciseness of mass spectroscopy measurements with the analyses made with other methods is performed. Some calculations and the tables of results are presented in appendixes. (J.S.)

  10. FLAME facility: The effect of obstacles and transverse venting on flame acceleration and transition on detonation for hydrogen-air mixtures at large scale

    International Nuclear Information System (INIS)

    Sherman, M.P.; Tieszen, S.R.; Benedick, W.B.

    1989-04-01

    This report describes research on flame acceleration and deflagration-to-detonation transition (DDT) for hydrogen-air mixtures carried out in the FLAME facility, and describes its relevance to nuclear reactor safety. Flame acceleration and DDT can generate high peak pressures that may cause failure of containment. FLAME is a large rectangular channel 30.5 m long, 2.44 m high, and 1.83 m wide. It is closed on the ignition end and open on the far end. The three test variables were hydrogen mole fraction (12--30%), degree of transverse venting (by moving steel top plates---0%, 13%, and 50%), and the absence or presence of certain obstacles in the channel (zero or 33% blockage ratio). The most important variable was the hydrogen mole fraction. The presence of the obstacles tested greatly increased the flame speeds, overpressures, and tendency for DDT compared to similar tests without obstacles. Different obstacle configurations could have greater or lesser effects on flame acceleration and DDT. Large degrees of transverse venting reduced the flame speeds, overpressures, and possibility of DDT. For small degrees of transverse venting (13% top venting), the flame speeds and overpressures were higher than for no transverse venting with reactive mixtures (>18% H 2 ), but they were lower with leaner mixtures. The effect of the turbulence generated by the flow out the vents on increasing flame speed can be larger than the effect of venting gas out of the channel and hence reducing the overpressure. With no obstacles and 50% top venting, the flame speeds and overpressures were low, and there was no DDT. For all other cases, DDT was observed above some threshold hydrogen concentration. DDT was obtained at 15% H 2 with obstacles and no transverse venting. 67 refs., 62 figs

  11. Hydrolysis of a mixture of saccharides by cellulase from Aspergillus niger and its application for visible-light-induced hydrogen gas production system using Mg chlorophyll-a and platinum nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Amao, Yutaka; Hirakawa, Takamasa [Department of Applied Chemistry, Oita University, Dannoharu 700, Oita 870-1192 (Japan)

    2010-07-15

    Cellulase obtained from Aspergillus niger was used to hydrolyze a mixture of saccharides containing sucrose, maltose, and cellobiose; the reduced form of nicotinamide-adenine dinucleotide (NAD{sup +}), which is NADH, was produced during hydrolysis of the mixture of saccharides in the presence of NAD{sup +} and glucose dehydrogenase (GDH). We have developed a visible-light-induced enzymatic biohydrogen production system involving the combination of cellulase-mediated hydrolysis of the mixture of saccharides and hydrogen production by platinum nanoparticles using photosensitization of Mg chlorophyll-a (Mg Chl-a). Continuous production of hydrogen gas was observed when the reaction mixture containing saccharides, cellulase, GDH, NAD{sup +}, Mg Chl-a, methylviologen (MV{sup 2+}, an electron donor), and platinum nanoparticles was irradiated by visible light. After 120 min of irradiation, the amount of hydrogen produced from the mixture of saccharides was approximately 2.8 {mu}mol. (author)

  12. 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.

  13. Cell growth and hydrogen production on the mixture of xylose and glucose using a novel strain of Clostridium sp. HR-1 isolated from cow dung compost

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ji-Fei; Ren, Nan-Qi; Wang, Ai-Jie; Qiu, Jie; Zhao, Qing-Liang; Feng, Yu-Jie; Liu, Bing-Feng [State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China)

    2010-12-15

    A novel mesophilic hydrogen-producing bacterium was isolated from cow dung compost and designated as Clostridium sp. HR-1 by 16S rRNA gene sequence. The optimum condition for hydrogen production by strain HR-1 was pH of 6.5, temperature of 37 C and yeast extract as nitrogen sources. The strain HR-1 has the ability to utilize kinds of hexose and pentose as carbon sources for growth and H{sub 2} production. Cell growth and hydrogen productivity were investigated for batch fermentation on media containing different ratios of xylose and glucose. Glucose was the preferred substrate in the glucose and xylose mixtures. The high glucose fraction had higher cell biomass production rate. The rate of glucose consumption was higher than xylose consumption, and remained essentially constant independent of xylose content of the mixture. The rate of xylose utilization was decreased with increasing of the glucose fraction. The average H{sub 2} yield and specific H{sub 2} production rates with xylose and glucose are 1.63 mol-H{sub 2}/mol xylose and 11.14-H{sub 2} mmol/h g-cdw, and 2.02 mol-H{sub 2}/mol-glucose and 9.37 mmol-H{sub 2}/h g-cdw, respectively. Using the same initial substrate concentration, the maximum average H{sub 2} yield and specific H{sub 2} production rates with the mixtures of 9 g/l xylose and 3 g/l glucose was 2.01 mol-H{sub 2}/mol-mixed sugar and 12.56 mmol-H{sub 2}/h g-cdw, respectively. During the fermentation, the main soluble microbial products were ethanol and acetate which showed trends with the different ratios of xylose and glucose. (author)

  14. Effect of isotopic hydrogen exchange on thermochemistry of solution of ammonium halides and deuteroammonium in water, heavy water and their mixtures with dimethylsulfoxide

    International Nuclear Information System (INIS)

    Egorov, G.I.

    1996-01-01

    Standard dissolution enthalpies of ammonium and deuteroammonium bromides and iodides in water, heavy water and their mixtures with dimethylsulfoxide (DMSO) at 298.15 K and compositions up to X=0.4 (X-mole part of DMSO) are presented. The influence of isotopic hydrogen exchange on the values of the standard dissolution enthalpies of NH 4 Cl, ND 4 Cl, NH 4 Br, ND 4 BR and NH 4 I in H 2 O, D 2 O and H 2 O (D 2 O)-DMSO mixture at 298.15 K, as well as of NH 4 Cl and ND 4 Cl in the same solvents at 323.15 K has been discussed. The values of NH 4 Cl and ND 4 Cl crystal lattice enthalpies have been compared. 15 refs., 3 tabs

  15. On the use of hydrogen peroxide as a masking agent for the determination of yttrium in uranium oxide - yttrium oxide mixture

    International Nuclear Information System (INIS)

    Rastogi, R.K.; Chaudhuri, N.K.; Rizvi, G.H.; Subramanian, M.S.

    1985-01-01

    The use of peroxide as a masking agent for uranium during the EDTA titration of yttrium in an yttrium-uranium mixture containing large amounts of uranium was investigated. High acetate ion concentration was necessary to keep the peroxy complex of uranium in solution during the titration. It was observed that uranium could be tolerated up to 500 mg in the determination of yttrium with 0.5 ml of 30% hydrogen peroxide in approx. 1M acetate medium. The precision and accuracy of the method based on 16 determinations of yttrium at 6-16 mg level in the presence of 300 mg uranium was found to be +-0.2%. (author)

  16. Development of Innovating Materials for Distributing Mixtures of Hydrogen and Natural Gas. Study of the Barrier Properties and Durability of Polymer Pipes

    Directory of Open Access Journals (Sweden)

    Klopffer Marie-Hélène

    2015-02-01

    Full Text Available With the growing place taken by hydrogen, a question still remains about its delivery and transport from the production site to the end user by employing the existing extensive natural gas pipelines. Indeed, the key challenge is the significant H2 permeation through polymer infrastructures (PolyEthylene (PE pipes, components such as connecting parts. This high flow rate of H2 through PE has to be taken into account for safety and economic requirements. A 3-year project was launched, the aim of which was to develop and assess material solutions to cope with present problems for hydrogen gas distribution and to sustain higher pressure compared to classical high density polyethylene pipe. This project investigated pure hydrogen gas and mixtures with natural gas (20% of CH4 and 80% of H2 in pipelines with the aim to select engineering polymers which are more innovative than polyethylene and show outstanding properties, in terms of permeation, basic mechanical tests but also more specific characterizations such as long term ageing and behaviour. The adequate benches, equipments and scientific approach for materials testing had been developed and validated. In this context, the paper will focus on the evaluation of the barrier properties of 3 polymers (PE, PA11 and PAHM. Experiments were performed for pure H2 and CH4 and also in the presence of mixtures of hydrogen and natural gas in order to study the possible mixing effects of gases. It will report some round-robin tests that have been carried out. Secondly, by comparing data obtained on film, polymer membrane and on pipe section, the influence of the polymer processing will be studied. Innovative multilayers systems will be proposed and compared on the basis of the results obtained on monolayer systems. Finally, the evolution of the transport properties of the studied polymers with an ageing under representative service conditions will be discussed.

  17. Toxicity of carbon monoxide hydrogen cyanide gas mixtures : exposure concentration, time to incapacitation, carboxyhemoglobin and blood cyanide parameters.

    Science.gov (United States)

    1994-04-01

    During aircraft interior fires, carbon monoxide (CO) and hydrogen cyanide (HCN) are produced in sufficient amounts to cause incapacitation and death. Time-to-incapacitation (ti) is a practical parameter for estimating escape time in fire environments...

  18. 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.

  19. Self adaptive internal combustion engine control for hydrogen mixtures using piezoelectric transducers for dynamic cylinder pressure monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Courteau, R.; Bose, T.K. [Quebec Univ., Trois-Rivieres, PQ (Canada). Institut de recherche sur l' hydrogene

    2004-07-01

    Hydrogen internal combustion engine research at the Hydrogen Research Institute includes the following infrastructure: a 20 square metre test cell, an engine preparation room, a 150 hp dynamometer, exhaust gas analysers and a hydrogen supply. The goal of the research is to develop internal combustion engine technologies that can use hydrogen as a fuel without knocking, backfires, excessive engine wear, and with low emissions. As well as hydrogen, fuels such as biogas are also investigated. Technologies under investigation include adaptive control algorithms, as well as advanced sensors and actuators. The latter include piezolelectrics, optical fibres, nitrogen oxide detectors, and chemical composition detectors. Developments include microprocessor-controlled injection and ignition control systems for both single cylinder and multicylinder engines. Research on the influence of fuel composition on best ignition timing is presented. There is also dynamic cylinder pressure monitoring to prevent knocking make engine state assessments and perform engine calibration. Piezoelectric cylinder pressure sensors are employed, either integrated with the spark plugs, or stand-alone, inserted through separate holes through the cylinder head. tabs, figs.

  20. THE ROLL-OVER OF HELIOSPHERIC NEUTRAL HYDROGEN BELOW 100 eV: OBSERVATIONS AND IMPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Galli, A.; Wurz, P. [Physics Institute, University of Bern, Bern, 3012 (Switzerland); Schwadron, N. A.; Kucharek, H.; Möbius, E. [University of New Hampshire, Durham, NH 03824 (United States); Bzowski, M.; Sokół, J. M.; Kubiak, M. A. [Space Research Centre, Polish Academy of Sciences, Warsaw, 00-716 (Poland); Funsten, H. O. [Los Alamos National Laboratory, Intelligence and Space Research Division, Los Alamos, NM 87545 (United States); Fuselier, S. A.; McComas, D. J. [Southwest Research Institute, San Antonio, TX 78228 (United States)

    2016-04-20

    We present an improved analysis of the energy spectrum of energetic neutral hydrogen from the heliosheath observed with the IBEX -Lo sensor on the Interstellar Boundary EXplorer from the years 2009 to 2012. This analysis allows us to study the lowest energies between 10 and 100 eV although various background sources are more intense than the targeted signal over broad areas of the sky. The results improve our knowledge of the interaction region between our heliosphere and the interstellar plasma because these neutral atoms are direct messengers from the low-energy plasma in the heliosheath. We find a roll-over of the energy spectrum below 100 eV, which has major implications for the pressure balance of the plasma in the inner heliosheath. The results can also be compared directly with in situ observations of the Voyager 1 and 2 spacecraft.

  1. Optimizing strategy for Escherichia coli growth and hydrogen production during glycerol fermentation in batch culture: Effects of some heavy metal ions and their mixtures

    International Nuclear Information System (INIS)

    Trchounian, Karen; Poladyan, Anna; Trchounian, Armen

    2016-01-01

    Highlights: • Effects of heavy metals on Escherichia coli were revealed during glycerol fermentation at pH 6.5. • Ni"2"+ + Fe"2"+ (0.05 mM) mixture stimulated up to 1.5-fold bacterial biomass yield. • Ni"2"+ + Fe"3"+ (0.05 mM), Ni"2"+ + Fe"3"+ + Mo"6"+ (0.02 mM) and Fe"3"+ + Mo"6"+ enhanced (up to 3-fold) H_2 production. • Discrimination between Fe"2"+ and Fe"3"+ was important for H_2 production. • Cu"+ and Cu"2"+ (0.1 mM) inhibited H_2 production. - Abstract: Hydrogen (H_2) is well-known effective, ecologically clean and renewable fuel. Bacterial H_2 production is a promising one and its use in industrial level is expected to increase in the nearest future to establish sustainable and renewable energy source. Escherichia coli wild type BW25113 growth yield was shown to be stimulated 1.3–1.5-fold by nickel (Ni"2"+), iron (Fe"2"+, Fe"3"+) ions and by some metal ion mixtures: Ni"2"+ + Fe"2"+ + molybdenum (Mo"6"+), Ni"2"+ + Fe"3"+, Ni"2"+ + Fe"2"+ and Mo"6"+ + Fe"3"+ in low concentrations (<0.05 mM) stimulated the growth during glycerol (10 g L"−"1) fermentation up to stationary phase at pH 6.5; Ni"2"+ + Fe"2"+ mixture showed the maximal effect. However, the same concentrations of these metals and their mixtures had no effects or slightly inhibited bacterial specific growth rate: it was suppressed ∼1.2-fold upon Ni"2"+, Fe"3"+, Mo"6"+ and Ni"2"+ + Mo"6"+ mixture supplementation. H_2 production by E. coli from glycerol was observed with the yield of 0.75 ± 0.02 mmol L"−"1. Moreover, H_2 yield was markedly stimulated 1.7–3-fold in the presence of Ni"2"+ + Fe"3"+, Ni"2"+ + Fe"3"+ + Mo"6"+ and Fe"3"+ + Mo"6"+ mixtures, but not sole metals: maximal stimulation was established by Fe"3"+ + Mo"6"+ mixture with the concentrations of 0.05 mM and 0.02 mM, respectively. While copper (Cu"+, Cu"2"+) ions in low concentration (0.1 mM) had H_2 production suppressing effect. The results point out that some heavy metal ions and their mixtures can stimulate E

  2. Hydrogen-rich gas production by continuous pyrolysis and in-line catalytic reforming of pine wood waste and HDPE mixtures

    International Nuclear Information System (INIS)

    Arregi, Aitor; Amutio, Maider; Lopez, Gartzen; Artetxe, Maite; Alvarez, Jon; Bilbao, Javier; Olazar, Martin

    2017-01-01

    Highlights: • Plastic co-feeding improves the flexibility of biomass pyrolysis-reforming strategy. • Hydrogen production is enhanced by increasing plastic content in the feed. • The joint valorization of biomass and plastics attenuates catalyst deactivation. • The amorphous coke derived from biomass is the main responsible for deactivation. - Abstract: The continuous pyrolysis-reforming of pine sawdust and high density polyethylene mixtures (25, 50 and 75 wt% HDPE) has been performed in a two-stage reaction system provided with a conical spouted bed reactor (CSBR) and a fluidized bed reactor. The influence HDPE co-feeding has on the conversion, yields and composition of the reforming outlet stream and catalyst deactivation has been studied at a reforming temperature of 700 °C, with a space time of 16.7 g_c_a_t min g_f_e_e_d_i_n_g"−"1 and a steam/(biomass + HDPE) mass ratio of 4, and a comparison has been made between these results and those recorded by feeding pine sawdust and HDPE separately. Co-feeding plastics enhances the hydrogen production, which increases from 10.9 g of H_2 per 100 g of feed (only pine sawdust in the feed) to 37.3 g of H_2 per 100 g of feed (only HDPE in the feed). Catalyst deactivation by coke is attenuated when HDPE is co-fed due to the lower content of oxygenated compounds in the reaction environment. The higher yield of hydrogen achieved with this two-step (pyrolysis-reforming) strategy, its ability to jointly valorise biomass and plastic mixtures and the lower temperatures required compared to gasification make this promising process for producing H_2 from renewable raw materials and wastes.

  3. Molecular Dynamics Simulations for Loading-Dependent Diffusion of CO2, SO2, CH4, and Their Binary Mixtures in ZIF-10: The Role of Hydrogen Bond.

    Science.gov (United States)

    Li, Li; Yang, Deshuai; Fisher, Trevor R; Qiao, Qi; Yang, Zhen; Hu, Na; Chen, Xiangshu; Huang, Liangliang

    2017-10-24

    The loading-dependent diffusion behavior of CH 4 , CO 2 , SO 2 , and their binary mixtures in ZIF-10 has been investigated in detail by using classical molecular dynamics simulations. Our simulation results demonstrate that the self-diffusion coefficient D i of CH 4 molecules decreases sharply and monotonically with the loading while those of both CO 2 and SO 2 molecules initially display a slight increase at low uptakes and follow a slow decrease at high uptakes. Accordingly, the interaction energies between CH 4 molecules and ZIF-10 remain nearly constant regardless of the loading due to the absence of hydrogen bonds (HBs), while the interaction energies between CO 2 (or SO 2 ) and ZIF-10 decease rapidly with the loading, especially at small amounts of gas molecules. Such different loading-dependent diffusion and interaction mechanisms can be attributed to the relevant HB behavior between gas molecules and ZIF-10. At low loadings, both the number and strength of HBs between CO 2 (or SO 2 ) molecules and ZIF-10 decrease obviously as the loading increases, which is responsible for the slight increase of their diffusion coefficients. However, at high loadings, their HB strength increases with the loading. Similar loading-dependent phenomena of diffusion, interaction, and HB behavior can be observed for CH 4, CO 2 , and SO 2 binary mixtures in ZIF-10, only associated with some HB competition between CO 2 and SO 2 molecules in the case of the CO 2 /SO 2 mixture.

  4. Sustainable hydrogen production from bio-oil model compounds (meta-xylene) and mixtures (1-butanol, meta-xylene and furfural).

    Science.gov (United States)

    Bizkarra, K; Barrio, V L; Arias, P L; Cambra, J F

    2016-09-01

    In the present work m-xylene and an equimolecular mixture of m-xylene, 1-butanol and furfural, all of them bio-oil model compounds, were studied in steam reforming (SR) conditions. Three different nickel catalysts, which showed to be active in 1-butanol SR (Ni/Al2O3, Ni/CeO2-Al2O3 and Ni/La2O3-Al2O3), were tested and compared with thermodynamic equilibrium values. Tests were carried out at temperatures from 800 to 600°C at atmospheric pressure with a steam to carbon ratio (S/C) of 5.0. Despite the different bio-oils fed, the amount of moles going through the catalytic bed was kept constant in order to obtain comparable results. After their use, catalysts were characterized by different techniques and those values were correlated with the activity results. All catalysts were deactivated during the SR of the mixture, mainly by coking. The highest hydrogen yields were obtained with Ni/Al2O3 and Ni/CeO2-Al2O3 catalysts in the SR of m-xylene and SR of the mixture, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Hydrogen radiolytic production in light and heavy water mixtures under conditions similar to LOCA (loss of coolant accidents)

    International Nuclear Information System (INIS)

    Garcia Rodenas, L.; Ali, S.P.; Liberman, S.J.

    1987-01-01

    H 2 , HD and D 2 radiolytic yield in heavy and light water mixtures has been determined to supply the necessary data which will allow to make a realistic estimation of the solution of such gas under LOCA conditions as a function of time. (Author)

  6. Modeling the Solid-Liquid Equilibrium in Pharmaceutical-Solvent Mixtures: Systems with Complex Hydrogen Bonding Behvaior

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Economou, Ioannis; Kontogeorgis, Georgios

    2009-01-01

    simpler molecules of similar chemical structure and/or are fitted to Hansen's partial solubility parameters. The methodology is applied to modeling the solubility of three pharmaceuticals, namely acetanilide, phenacetin, and paracetamol, using the nonrandom hydrogen bonding (NRHB) EoS. In all cases...

  7. Hydrogen-rich gas as a product of two-stage co-gasification of lignite/waste mixtures

    Czech Academy of Sciences Publication Activity Database

    Straka, Pavel; Bičáková, Olga

    2014-01-01

    Roč. 39, č. 21 (2014), s. 10987-10995 ISSN 0360-3199 Institutional support: RVO:67985891 Keywords : co-gasification * waste plastics * lignite * hydrogen-rich gas Subject RIV: DM - Solid Waste and Recycling Impact factor: 3.313, year: 2014 http://authors.elsevier.com/sd/article/S0360319914014025

  8. Chlorine disinfection of dye wastewater: Implications for a commercial azo dye mixture

    Energy Technology Data Exchange (ETDEWEB)

    Vacchi, Francine Inforcato; Albuquerque, Anjaina Fernandes; Vendemiatti, Josiane Aparecida; Morales, Daniel Alexandre [Faculdade de Tecnologia, Universidade Estadual de Campinas, Limeira, SP, 13484-332 (Brazil); Ormond, Alexandra B.; Freeman, Harold S. [Department of Textile Engineering, Chemistry, and Science, North Carolina State University, Raleigh, NC 27695-8301 (United States); Zocolo, Guilherme Juliao; Zanoni, Maria Valnice Boldrin [Departamento de Quimica Analitica, Universidade Estadual Paulista Julio de Mesquita Filho, Instituto de Quimica de Araraquara, Araraquara, SP 14801-970 (Brazil); Umbuzeiro, Gisela, E-mail: giselau@ft.unicamp.br [Faculdade de Tecnologia, Universidade Estadual de Campinas, Limeira, SP, 13484-332 (Brazil)

    2013-01-01

    Azo dyes, the most widely used family of synthetic dyes, are often employed as colorants in areas such as textiles, plastics, foods/drugs/cosmetics, and electronics. Following their use in industrial applications, azo dyes have been found in effluents and various receiving waters. Chemical treatment of effluents containing azo dyes includes disinfection using chlorine, which can generate compounds of varying eco/genotoxicity. Among the widely known commercial azo dyes for synthetic fibers is C.I. Disperse Red 1. While this dye is known to exist as a complex mixture, reports of eco/genotoxicity involve the purified form. Bearing in mind the potential for adverse synergistic effects arising from exposures to chemical mixtures, the aim of the present study was to characterize the components of commercial Disperse Red 1 and its chlorine-mediated decoloration products and to evaluate their ecotoxicity and mutagenicity. In conducting the present study, Disperse Red 1 was treated with chlorine gas, and the solution obtained was analyzed with the aid of LC-ESI-MS/MS to identify the components present, and then evaluated for ecotoxicity and mutagenicity, using Daphnia similis and Salmonella/microsome assays, respectively. The results of this study indicated that chlorination of Disperse Red 1 produced four chlorinated aromatic compounds as the main products and that the degradation products were more ecotoxic than the parent dye. These results suggest that a disinfection process using chlorine should be avoided for effluents containing hydrophobic azo dyes such commercial Disperse Red 1. -- Highlights: Black-Right-Pointing-Pointer Aqueous solutions of Disperse Red 1 were treated with chlorine. Black-Right-Pointing-Pointer The chlorination products of Disperse Red 1 were identified using LC-ESI-MS/MS. Black-Right-Pointing-Pointer Daphnia and Salmonella/microsome were employed for eco/genotoxicity testing. Black-Right-Pointing-Pointer The chlorinated dye was more mutagenic

  9. Chlorine disinfection of dye wastewater: Implications for a commercial azo dye mixture

    International Nuclear Information System (INIS)

    Vacchi, Francine Inforçato; Albuquerque, Anjaina Fernandes; Vendemiatti, Josiane Aparecida; Morales, Daniel Alexandre; Ormond, Alexandra B.; Freeman, Harold S.; Zocolo, Guilherme Julião; Zanoni, Maria Valnice Boldrin; Umbuzeiro, Gisela

    2013-01-01

    Azo dyes, the most widely used family of synthetic dyes, are often employed as colorants in areas such as textiles, plastics, foods/drugs/cosmetics, and electronics. Following their use in industrial applications, azo dyes have been found in effluents and various receiving waters. Chemical treatment of effluents containing azo dyes includes disinfection using chlorine, which can generate compounds of varying eco/genotoxicity. Among the widely known commercial azo dyes for synthetic fibers is C.I. Disperse Red 1. While this dye is known to exist as a complex mixture, reports of eco/genotoxicity involve the purified form. Bearing in mind the potential for adverse synergistic effects arising from exposures to chemical mixtures, the aim of the present study was to characterize the components of commercial Disperse Red 1 and its chlorine-mediated decoloration products and to evaluate their ecotoxicity and mutagenicity. In conducting the present study, Disperse Red 1 was treated with chlorine gas, and the solution obtained was analyzed with the aid of LC–ESI-MS/MS to identify the components present, and then evaluated for ecotoxicity and mutagenicity, using Daphnia similis and Salmonella/microsome assays, respectively. The results of this study indicated that chlorination of Disperse Red 1 produced four chlorinated aromatic compounds as the main products and that the degradation products were more ecotoxic than the parent dye. These results suggest that a disinfection process using chlorine should be avoided for effluents containing hydrophobic azo dyes such commercial Disperse Red 1. -- Highlights: ► Aqueous solutions of Disperse Red 1 were treated with chlorine. ► The chlorination products of Disperse Red 1 were identified using LC–ESI-MS/MS. ► Daphnia and Salmonella/microsome were employed for eco/genotoxicity testing. ► The chlorinated dye was more mutagenic than the dye itself. ► Chlorination should be avoided in effluents containing azo-dyes.

  10. Mock-up tests on the combustion of hydrogen-air mixture in the vertical tube simulating the CNS channel of the CARR

    International Nuclear Information System (INIS)

    Yu Qingfeng; Feng Quanke; Kawai, Takeshi; Xu Jian

    2007-01-01

    A two-phase thermo-siphon loop for removing nuclear heating and maintaining the stable liquid level in the moderator cell was adopted for the cold neutron source (CNS) of the China advanced research reactor (CARR). The moderator is liquid hydrogen. The two-phase thermo-siphon loop consists of the crescent-shape moderator cell, the moderator transfer tube, and the condenser. The hydrogen is supplied from the buffer tank to the condenser. The main feature of the loop is that the moderator cell is covered by the helium sub-cooling system. The cold helium gas from the helium refrigerator is firstly introduced into the helium sub-cooling system and then flows up through the tube covering the moderator transfer tube into the condenser. The main part of this system is installed in the CNS vertical channel made of aluminum alloy 6061 T6 (Al-6061-T6) of 6 mm in thickness, 270 mm in outer diameter and about 6 m in height. For confirming the safety of the CNS channel, the combustion tests using a tube compatible with the CNS channel were carried out using the hydrogen-air mixture under which air is introduced into the tube at 1 atmosphere, and then hydrogen gas is supplied from the gas cylinder up to the test pressures. And maximum test pressure is 0.14 MPa G. This condition is involved with the maximum design basis accident of the CARR-CNS. The peak pressure due to combustion was 1.09 MPa, and the design pressure of the CNS channel is 3 MPa. The safety of the CNS was thus verified even if the maximum design basis accident occurs. The pressure and stress distributions along the axial direction and the displacement of the tube were also measured

  11. The nitriding of solution treated A1S1 type 316 stainless steel in ammonia-hydrogen mixtures

    International Nuclear Information System (INIS)

    Tyfield, S.P.; Mackway, J.

    1975-08-01

    A study is described of the nitriding of 316 stainless steel in NH 3 /H 2 mixtures between 500 0 C and 800 0 C to examine the application of the rate data, so obtained, to nitriding in molecular nitrogen. The rate of nitriding in NH 3 -H 2 was found to be parabolic, at nitrogen potentials insufficient to produce surface iron nitrodes. The rate determining process is interpreted to be dependent on both chromium nitride precipitation and nitrogen diffusion. It is concluded that the kinetics of nitriding 316 stainless steel in molecular nitrogen between 500 0 C and 800 0 C are not reliably predicted on the basis of accelerated kinetic results produced either by increasing the nitrogen potential by the use of NH 3 /H 2 mixtures or by elevating the temperature as reported elsewhere. (U.K.)

  12. Diagnostics of Hydrogen-Containing Mixture Compression by a Two-Stage Piston Compressor with Cooling Demand Prediction

    Directory of Open Access Journals (Sweden)

    Tomáš Brestovič

    2018-04-01

    Full Text Available The present article describes the diagnostics of a compressor that is compressing a mixture of H2 and N2 on the basis of the results that were obtained by operational measurements of the flow rates and temperatures at selected compressor sites, as well as of the acoustic pressure levels during the full loading thereof. The obtained data were subsequently used to determine the limit conditions of the compressor operations in terms of the cooling capacity. A thermodynamic analysis of the compression of the H2/N2 gas mixture was carried out with subsequent heat and energy flow calculation and the determination of the minimum cooling water flow rate that is required to ensure the continuous compressor operations.

  13. Co-pyrolysis of waste tire/coal mixtures for smokeless fuel, maltenes and hydrogen-rich gas production

    Czech Academy of Sciences Publication Activity Database

    Bičáková, Olga; Straka, Pavel

    2016-01-01

    Roč. 116, MAY 15 (2016), s. 203-213 ISSN 0196-8904 Grant - others:OPPK(XE) CZ.2.16/3.1.00/21538 Program:OPPK Institutional support: RVO:67985891 Keywords : waste tires * coal * co-pyrolysis * smokeless fuel * tar * hydrogen -rich gas Subject RIV: DM - Solid Waste and Recycling Impact factor: 5.589, year: 2016 http://www.sciencedirect.com/science/article/pii/S0196890416300991

  14. UO{sub 2} surface oxidation by mixtures of water vapor and hydrogen as a function of temperature

    Energy Technology Data Exchange (ETDEWEB)

    Espriu-Gascon, A., E-mail: alexandra.espriu@upc.edu [Department of Chemical Engineering, Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Llorca, J.; Domínguez, M. [Institut de Tècniques Energètiques (INTE), Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Centre for Research in NanoEngineering (CRNE), Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Giménez, J.; Casas, I. [Department of Chemical Engineering, Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Pablo, J. de [Department of Chemical Engineering, Universitat Politècnica Catalunya-Barcelona Tech, Diagonal 647, E-08028 Barcelona (Spain); Fundació CTM Centre Tecnològic, Plaça de la Ciència 2, E-08243 Manresa (Spain)

    2015-12-15

    In the present work, X-Ray Photoelectron Spectroscopy (XPS) was used to study the effect of water vapor on the UO{sub 2} surface as a function of temperature. The experiments were performed in situ inside a high pressure chamber attached to the XPS instrument. UO{sub 2} samples were put in contact with either hydrogen or argon streams, saturated with water at room temperature, and the sample surface evolution was analyzed by XPS. In the case of the water vapor/argon experiments, one experiment at 350 °C was performed and, in the case of the water vapor/hydrogen experiments, the temperatures used inside the reactor were 60, 120, 200 and 350 °C. On one hand, in presence of argon, the results obtained showed that the water vapor in the argon stream oxidized 93% of the U(IV) in the sample surface. On the other hand, the degree of UO{sub 2} surface oxidation showed a different dependence on the temperature in the experiments performed in the presence of hydrogen: the maximum surface oxidation occurred at 120 °C, where 65.4% of U(IV) in the sample surface was oxidized, while at higher temperatures, the surface oxidation decreased. This observation is attributed to the increase of hydrogen reducing effect when temperature increases which prevents part of the oxidation of the UO{sub 2} surface by the water vapor. - Highlights: • UO{sub 2} surface has been oxidized by water vapor in an argon stream at 350 °C. • H{sub 2} reduced more uranium oxidation produced by water at 350 °C when compared to Ar. • In H{sub 2} presence, the uranium oxidation produced by water depends on the temperature.

  15. Hydrophobic fluorine mediated switching of the hydrogen bonding site as well as orientation of water molecules in the aqueous mixture of monofluoroethanol: IR, molecular dynamics and quantum chemical studies.

    Science.gov (United States)

    Mondal, Saptarsi; Biswas, Biswajit; Nandy, Tonima; Singh, Prashant Chandra

    2017-09-20

    The local structures between water-water, alcohol-water and alcohol-alcohol have been investigated for aqueous mixtures of ethanol (ETH) and monofluoroethanol (MFE) by the deconvolution of IR bands in the OH stretching region, molecular dynamics simulation and quantum chemical calculations. It has been found that the addition of a small amount of ETH into the aqueous medium increases the strength of the hydrogen bonds between water molecules. In an aqueous mixture of MFE, the substitution of a single fluorine induces a change in the orientation as well as the hydrogen bonding site of water molecules from the oxygen to the fluorine terminal of MFE. The switching of the hydrogen bonding site of water in the aqueous mixture of MFE results in comparatively strong hydrogen bonds between MFE and water molecules as well as less clustering of water molecules, unlike the case of the aqueous mixture of ETH. These findings about the modification of a hydrogen bond network by the hydrophobic fluorine group probably make fluorinated molecules useful for pharmaceutical as well as biological applications.

  16. Hydrogen production in early generation fusion power plant and its socio-economic implication

    International Nuclear Information System (INIS)

    Konishi, S.; Yamamoto, Y.

    2007-01-01

    Full text: This paper describes technical possibility of high temperature blanket for the early generation of fusion power plant and its application to hydrogen production. Its anticipated implication and strategy from the socio-economic aspects will be also discussed. Material and energy balances, such as fuel supply and delivery of product energy from fusion plants, as well as waste discharge and accident scenario that lead to environmental impact, are characterized by blanket concepts. Thus blankets are considered to dominate the feature of fusion energy that should respond to the requirements of the sponsors, i.e., public and future market. Fusion blanket concept based on the combinations of LiPb and SiC materials are regarded as a candidate for ITER/TBM, and at the same time, applied in various DEMO designs encompassing high temperature output. Recent developments of SiC-LiPb blanket in Japan, EU, US or China suggests staged development paths starting from TBMs and targeting high temperature blanket and efficient energy output from early generation plants. These strategies are strongly affected by the views of these parties on fusion energy, from the aspects of socio-economics. Hydrogen production process with the high temperature blanket is one of the most important issues, because temperature range much higher than is possible with current or near future fission plants are needed, suggesting market possibility different from that of fission. Fuel cycles, particularly lithium supply and TBR control will be also important. Self-sustained fusion fuel cycle requires technical capability to maintain the lithium contents. Liquid blanket has an advantage in continuous and real-time control TBR in a plant, but large amount of lithium-6 and initial tritium supply remains as issues. As for the environmental effect, normal operation release, assumed accidental scenario, and rad-waste will be the key issue to dominate social acceptance of fusion. (author)

  17. Hydrogen production in early generation fusion power plant and its socio-economic implication

    International Nuclear Information System (INIS)

    Konishi, Satoshi; Yamamoto, Yasushi

    2008-01-01

    This paper describes technical possibility of high temperature blanket for the early generation of fusion power plant and its application to hydrogen production. Its anticipated implication and strategy from the socio-economic aspects will be also discussed. Material and energy balances, such as fuel supply and delivery of product energy from fusion plants, as well as waste discharge and accident scenario that lead to environmental impact, are characterized by blanket concepts. Thus blankets are considered to dominate the feature of fusion energy that should respond to the requirements of the sponsors, i.e., public and future market. Fusion blanket concept based on the combinations of LiPb and SiC materials are regarded as a candidate for ITER/TBM, and at the same time, applied in various DEMO designs encompassing high temperature output. Recent developments of SiC-LiPb blanket in Japan, EU, US or China suggests staged development paths starting from TBMs and targeting high temperature blanket and efficient energy output from early generation plants. These strategies are strongly affected by the views of these parties on fusion energy, from the aspects of socio-economics. Hydrogen production process with the high temperature blanket is one of the most important issues, because temperature range much higher than is possible with current or near future fission plants are needed, suggesting market possibility different from that of fission. Fuel cycles, particularly lithium supply and TBR control will be also important. Self-sustained fusion fuel cycle requires technical capability to maintain the lithium contents. Liquid blanket has an advantage in continuous and real-time control TBR in a plant, but large amount of lithium-6 and initial tritium supply remains as issues. As for the environmental effect, normal operation release, assumed accidental scenario, and rad-waste will be the key issue to dominate social acceptance of fusion. (author)

  18. The life cycle greenhouse gas emissions implications of power and hydrogen production for oil sands operations

    International Nuclear Information System (INIS)

    McKellar, J.M.; Bergerson, J.A.; MacLean, H.L.

    2009-01-01

    'Full text:' The Alberta Oil Sands represent a major economic opportunity for Canada, but the industry is also a significant source of greenhouse gas (GHG) emissions. One of the sources of these emissions is the use of natural gas for the production of electricity, steam and hydrogen. Due to concerns around resource availability and price volatility, there has been considerable discussion regarding the potential replacement of natural gas with an alternative fuel. While some of the options are non-fossil and could potentially reduce GHG emissions (e.g., nuclear, geothermal, biomass), others have the potential to increase emissions. A comparative life cycle assessment was completed to investigate the relative GHG emissions, energy consumption and financial implications of replacing natural gas with coal, coke, asphaltenes or bitumen for the supply of electricity, steam and hydrogen to oil sands operations. The potential use of carbon capture and storage (CCS) was also investigated as a means of reducing GHG emissions. Preliminary results indicate that, without CCS, the natural gas systems currently in use have lower life cycle GHG emissions than gasification systems using any of the alternative fuels analysed. However, when CCS is implemented in both the coke gasification and natural gas systems, the coke systems have lower GHG emissions and financial costs than the natural gas systems (assuming a 30-year project life and a natural gas price of 6.5 USD/gigajoule). The use of CCS does impose a financial penalty though, indicating that it is unlikely to be implemented without some financial incentive. While this study has limitations and uncertainties, the preliminary results indicate that although the GHG emissions of oil sands development pose a challenge to Canada, there are opportunities available for their abatement. (author)

  19. Gas barrier properties of hydrogenated amorphous carbon films coated on polyethylene terephthalate by plasma polymerization in argon/n-hexane gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Polonskyi, Oleksandr; Kylián, Ondřej, E-mail: ondrej.kylian@gmail.com; Petr, Martin; Choukourov, Andrei; Hanuš, Jan; Biederman, Hynek

    2013-07-01

    Hydrogenated amorphous carbon thin films were deposited by RF plasma polymerization in argon/n-hexane gas mixture on polyethylene terephthalate (PET) foils. It was found that such deposited films may significantly improve the barrier properties of PET. It was demonstrated that the principal parameter that influences barrier properties of such deposited films towards oxygen and water vapor is the density of the coatings. Moreover, it was shown that for achieving good barrier properties it is advantageous to deposit coatings with very low thickness. According to the presented results, optimal thickness of the coating should not be higher than several tens of nm. - Highlights: • a-C:H films were prepared by plasma polymerization in Ar/n-hexane atmosphere. • Barrier properties of coatings are dependent on their density and thickness. • Highest barrier properties were observed for films with thickness 15 nm.

  20. Development of proton conducting materials and membranes based on lanthanum tungstate for hydrogen separation from gas mixtures

    International Nuclear Information System (INIS)

    Seeger, Janka

    2013-01-01

    Lanthanum tungstate La 6-x WO 12-δ (named LWO) is a ceramic material with mixed protonic electronic conductivity. Thereby it is a good candidate membrane material for hydrogen separation from synthesis gas in a fossil pre-combustion power plant. This work shows a material optimization by substitution targeted to clearly enhance the mixed conductivity and thereby the hydrogen flow through the LWO membrane. The first part of the work shows the synthesis and characterization of unsubstituted LWO. It points out that monophase LWO powder can be reproducibly synthesized. The La/W-ratio has to be considerably smaller than the nominal ratio of La/W = 6.0. It also depends on the used sintering conditions. Different relevant properties of LWO like stability in conditions close to application, thermal expansion, sintering behavior or microstructure were determined. Furthermore, the electrical conductivity of the material was investigated. LWO exhibits a prevailing protonic conductivity up to 750 C in wet atmospheres. Under dry atmospheres n-type conductivity was dominating. Oxygen ion and n-type conductivity dominated in wet and dry atmospheres above 750 C. The main part of the work is concerned with the development of new LWO based materials by substitutions. The aim is to achieve an improved mixed protonic electronic conductivity. Substitution elements for lanthanum side were Mg, Ca, Sr, Ba, Ce, Nd, Tb, Y and Al, while for the tungsten side Mo, Re and Ir were used. The total conductivity of the developed materials was investigated and compared to that of the unsubstituted LWO. The substitution of lanthanum led to no appreciable enhancement of the conductivity whereas the substitution of tungsten with 20 mol% molybdenum or 20 mol% rhenium clearly improved it. This caused a hydrogen flow about seven times higher for 20 mol% molybdenum- and about ten times higher for 20 mol% rhenium-substituted LWO in comparison with the unsubstituted LWO at 700 C. In the last part of the

  1. Investigation on the performance and emission parameters of dual fuel diesel engine with mixture combination of hydrogen and producer gas as secondary fuel

    Directory of Open Access Journals (Sweden)

    A. E. Dhole

    2016-06-01

    Full Text Available This study presents experimental investigation in to the effects of using mixture of producer gas and hydrogen in five different proportions as a secondary fuel with diesel as pilot fuel at wide range of load conditions in dual fuel operation of a 4 cylinder turbocharged and intercooled 62.5 kW gen-set diesel engine at constant speed of 1500 RPM. Secondary fuel Substitution is in different percentage of diesel at each load. To generate producer gas, the rice husk was used as source in the downdraft gasifier. The performance and emission characteristics of the dual fuel engine are compared with that of diesel engine at different load conditions. It was found that of all the combinations tested, mixture combination of PG:H2=(60:40% is the most suited one at which the brake thermal efficiency is in good comparison to that of diesel operation. Decreased NOx emissions and increased CO emissions were observed for dual fuel mode for all the fuel combinations compared to diesel fuel operation.

  2. Synthesis and optical properties of BCxNy films deposited from N-triethylborazine and hydrogen mixture

    International Nuclear Information System (INIS)

    Sulyaeva, Veronica S.; Rumyantsev, Yurii M.; Kesler, Valerii G.; Kosinova, Marina L.

    2015-01-01

    BC x N y films were obtained by plasma enhanced chemical vapor deposition method using a single-source precursor N-triethylborazine and hydrogen as plasma activating gas. The effect of synthesis temperature on the chemical composition and properties of the BC x N y films was investigated. The BC x N y films were examined by scanning electron microscopy, Fourier transform infrared and Raman spectroscopy, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and ellipsometry and spectrophotometry techniques. These experimental results indicated that the BC x N y films produced at low temperatures (T dep ≤ 673 K) are the polymer-like hydrogenated films with high transparency up to 93% in the visible part of the spectrum. BC x N y films produced at high temperatures (> 673 K) contain additional phase of disordered carbon which has dramatically reduce transparency. The band gap of the films varied from 0.6 to 4.5 eV, with variation in deposition temperature. - Highlights: • Thin BC x N y films have been obtained by plasma enhanced chemical vapor deposition. • N-triethylborazine was used as a precursor. • Low temperature BC x N y films were found to be high optical transparent layers (93%). • Optical band gap of the BC x N y layers varied from 0.6 to 4.5 eV

  3. Thin, High-Flux, Self-Standing, Graphene Oxide Membranes for Efficient Hydrogen Separation from Gas Mixtures.

    Science.gov (United States)

    Bouša, Daniel; Friess, Karel; Pilnáček, Kryštof; Vopička, Ondřej; Lanč, Marek; Fónod, Kristián; Pumera, Martin; Sedmidubský, David; Luxa, Jan; Sofer, Zdeněk

    2017-08-22

    The preparation and gas-separation performance of self-standing, high-flux, graphene oxide (GO) membranes is reported. Defect-free, 15-20 μm thick, mechanically stable, unsupported GO membranes exhibited outstanding gas-separation performance towards H 2 /CO 2 that far exceeded the corresponding 2008 Robeson upper bound. Remarkable separation efficiency of GO membranes for H 2 and bulky C 3 or C 4 hydrocarbons was achieved with high flux and good selectivity at the same time. On the contrary, N 2 and CH 4 molecules, with larger kinetic diameter and simultaneously lower molecular weight, relative to that of CO 2 , remained far from the corresponding H 2 /N 2 or H 2 /CH 4 upper bounds. Pore size distribution analysis revealed that the most abundant pores in GO material were those with an effective pore diameter of 4 nm; therefore, gas transport is not exclusively governed by size sieving and/or Knudsen diffusion, but in the case of CO 2 was supplemented by specific interactions through 1) hydrogen bonding with carboxyl or hydroxyl functional groups and 2) the quadrupole moment. The self-standing GO membranes presented herein demonstrate a promising route towards the large-scale fabrication of high-flux, hydrogen-selective gas membranes intended for the separation of H 2 /CO 2 or H 2 /alkanes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Thermocatalytic Behavior of Manganese (IV Oxide as Nanoporous Material on the Dissociation of a Gas Mixture Containing Hydrogen Peroxide

    Directory of Open Access Journals (Sweden)

    Zaid B. Jildeh

    2018-04-01

    Full Text Available In this article, we present an overview on the thermocatalytic reaction of hydrogen peroxide (H 2 O 2 gas on a manganese (IV oxide (MnO 2 catalytic structure. The principle of operation and manufacturing techniques are introduced for a calorimetric H 2 O 2 gas sensor based on porous MnO 2 . Results from surface analyses by X-ray photoelectron spectroscopy (XPS and scanning electron microscopy (SEM of the catalytic material provide indication of the H 2 O 2 dissociation reaction schemes. The correlation between theory and the experiments is documented in numerical models of the catalytic reaction. The aim of the numerical models is to provide further information on the reaction kinetics and performance enhancement of the porous MnO 2 catalyst.

  5. Thermocatalytic Behavior of Manganese (IV) Oxide as Nanoporous Material on the Dissociation of a Gas Mixture Containing Hydrogen Peroxide.

    Science.gov (United States)

    Jildeh, Zaid B; Oberländer, Jan; Kirchner, Patrick; Wagner, Patrick H; Schöning, Michael J

    2018-04-21

    In this article, we present an overview on the thermocatalytic reaction of hydrogen peroxide (H 2 O 2 ) gas on a manganese (IV) oxide (MnO 2 ) catalytic structure. The principle of operation and manufacturing techniques are introduced for a calorimetric H 2 O 2 gas sensor based on porous MnO 2 . Results from surface analyses by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) of the catalytic material provide indication of the H 2 O 2 dissociation reaction schemes. The correlation between theory and the experiments is documented in numerical models of the catalytic reaction. The aim of the numerical models is to provide further information on the reaction kinetics and performance enhancement of the porous MnO 2 catalyst.

  6. Fluid phase equilibria of the reaction mixture during the selective hydrogenation of 2-butenal in dense carbon dioxide

    DEFF Research Database (Denmark)

    Musko, Nikolai; Jensen, Anker Degn; Baiker, Alfons

    2012-01-01

    Knowledge of the phase behaviour and composition is of paramount importance for understanding multiphase reactions. We have investigated the effect of the phase behaviour in the palladium-catalysed selective hydrogenation of 2-butenal to saturated butanal in dense carbon dioxide. The reactions were...... cell. The results of the catalytic experiments showed that small amounts of carbon dioxide added to the system significantly decrease the conversion, whereas at higher loadings of CO2 the reaction rate gradually increases reaching a maximum. The CPA calculations revealed that this maximum is achieved...... performed using a 5wt% Pd on activated carbon in custom-designed high pressure autoclaves at 323K. The Cubic-Plus-Association (CPA) equation of state was employed to model the phase behaviour of the experimentally studied systems. CPA binary interaction parameters were estimated based on the experimental...

  7. Collision-Induced Infrared Absorption by Collisional Complexes in Dense Hydrogen-Helium Gas Mixtures at Thousands of Kelvin

    Science.gov (United States)

    Abel, Martin; Frommhold, Lothar; Li, Xiaoping; Hunt, Katharine L. C.

    2011-06-01

    The interaction-induced absorption by collisional pairs of H{_2} molecules is an important opacity source in the atmospheres of the outer planets and cool stars. The emission spectra of cool white dwarf stars differ significantly in the infrared from the expected blackbody spectra of their cores, which is largely due to absorption by collisional H{_2}-H{_2}, H{_2}-He, and H{_2}-H complexes in the stellar atmospheres. Using quantum-chemical methods we compute the atmospheric absorption from hundreds to thousands of kelvin. Laboratory measurements of interaction-induced absorption spectra by H{_2} pairs exist only at room temperature and below. We show that our results reproduce these measurements closely, so that our computational data permit reliable modeling of stellar atmosphere opacities even for the higher temperatures. L. Frommhold, Collision-Induced Absorption in Gases, Cambridge University Press, Cambridge, New York, 1993 and 2006 Xiaoping Li, Katharine L. C. Hunt, Fei Wang, Martin Abel, and Lothar Frommhold, "Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin", International Journal of Spectroscopy, vol. 2010, Article ID 371201, 11 pages, 2010. doi: 10.1155/2010/371201 M. Abel, L. Frommhold, X. Li, and K. L. C. Hunt, "Collision-induced absorption by H{_2} pairs: From hundreds to thousands of Kelvin," J. Phys. Chem. A, published online, DOI: 10.1021/jp109441f L. Frommhold, M. Abel, F. Wang, M. Gustafsson, X. Li, and K. L. C. Hunt, "Infrared atmospheric emission and absorption by simple molecular complexes, from first principles", Mol. Phys. 108, 2265, 2010

  8. Toxicity of binary mixtures of metals and pyrethroid insecticides to Daphnia magna Straus. Implications for multi-substance risks assessment

    Energy Technology Data Exchange (ETDEWEB)

    Barata, Carlos [Laboratory of Environmental Toxicology, Universitat Poltiecnica de Catalunya, CN 150 Km 14.5, Terrassa 08220 (Spain)]. E-mail: barata@intexter.upc.edu; Baird, D.J. [National Water Research Institute (Environment Canada) at Canadian Rivers Institute, 10 Bailey Drive, PO Box 45111, University of New Brunswick, Fredericton E3B 6E1, New Brunswick (Canada); Nogueira, A.J.A. [Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Soares, A.M.V.M. [Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Riva, M.C. [Laboratory of Environmental Toxicology, Universitat Poltiecnica de Catalunya, CN 150 Km 14.5, Terrassa 08220 (Spain)

    2006-06-10

    Two different concepts, termed concentration addition (CA) and independent action (IA), describe general relationships between the effects of single substances and their corresponding mixtures allowing calculation of an expected mixture toxicity on the basis of known toxicities of the mixture components. Both concepts are limited to cases in which all substances in a mixture influence the same experimental endpoint, and are usually tested against a 'fixed ratio design' where the mixture ratio is kept constant throughout the studies and the overall concentration of the mixture is systematically varied. With this design, interaction among toxic components across different mixture ratios and endpoints (i.e. lethal versus sublethal) is not assessed. In this study lethal and sublethal (feeding) responses of Daphnia magna individuals to single and binary combinations of similarly and dissimilarly acting chemicals including the metals (cadmium, copper) and the pyrethroid insecticides ({lambda}-cyhalothrin and deltamethrin) were assayed using a composite experimental design to test for interactions among toxic components across mixture effect levels, mixture ratios, lethal and sublethal toxic effects. To account for inter-experiment response variability, in each binary mixture toxicity assay the toxicity of the individual mixture constituents was also assessed. Model adequacy was then evaluated comparing the slopes and elevations of predicted versus observed mixture toxicity curves with those estimated for the individual components. Model predictive abilities changed across endpoints. The IA concept was able to predict accurately mixture toxicities of dissimilarly acting chemicals for lethal responses, whereas the CA concept did so in three out of four pairings for feeding response, irrespective of the chemical mode of action. Interaction effects across mixture effect levels, evidenced by crossing slopes, were only observed for the binary mixture Cd and Cu for

  9. Toxicity of binary mixtures of metals and pyrethroid insecticides to Daphnia magna Straus. Implications for multi-substance risks assessment

    International Nuclear Information System (INIS)

    Barata, Carlos; Baird, D.J.; Nogueira, A.J.A.; Soares, A.M.V.M.; Riva, M.C.

    2006-01-01

    Two different concepts, termed concentration addition (CA) and independent action (IA), describe general relationships between the effects of single substances and their corresponding mixtures allowing calculation of an expected mixture toxicity on the basis of known toxicities of the mixture components. Both concepts are limited to cases in which all substances in a mixture influence the same experimental endpoint, and are usually tested against a 'fixed ratio design' where the mixture ratio is kept constant throughout the studies and the overall concentration of the mixture is systematically varied. With this design, interaction among toxic components across different mixture ratios and endpoints (i.e. lethal versus sublethal) is not assessed. In this study lethal and sublethal (feeding) responses of Daphnia magna individuals to single and binary combinations of similarly and dissimilarly acting chemicals including the metals (cadmium, copper) and the pyrethroid insecticides (λ-cyhalothrin and deltamethrin) were assayed using a composite experimental design to test for interactions among toxic components across mixture effect levels, mixture ratios, lethal and sublethal toxic effects. To account for inter-experiment response variability, in each binary mixture toxicity assay the toxicity of the individual mixture constituents was also assessed. Model adequacy was then evaluated comparing the slopes and elevations of predicted versus observed mixture toxicity curves with those estimated for the individual components. Model predictive abilities changed across endpoints. The IA concept was able to predict accurately mixture toxicities of dissimilarly acting chemicals for lethal responses, whereas the CA concept did so in three out of four pairings for feeding response, irrespective of the chemical mode of action. Interaction effects across mixture effect levels, evidenced by crossing slopes, were only observed for the binary mixture Cd and Cu for lethal effects

  10. Hydrogen storage properties of rare earth (RE) borohydrides (RE = La, Er) in composite mixtures with LiBH{sub 4} and LiH

    Energy Technology Data Exchange (ETDEWEB)

    Frommen, Christoph; Heere, Michael [Institute for Energy Technology, Physics Department, P.O. Box 40, NO-2027 Kjeller (Norway); Riktor, Marit D. [Institute for Energy Technology, Physics Department, P.O. Box 40, NO-2027 Kjeller (Norway); SINTEF Materials and Chemistry, Forskningsveien 1, NO-0314 Oslo (Norway); Sørby, Magnus H. [Institute for Energy Technology, Physics Department, P.O. Box 40, NO-2027 Kjeller (Norway); Hauback, Bjørn C., E-mail: bjorn.hauback@ife.no [Institute for Energy Technology, Physics Department, P.O. Box 40, NO-2027 Kjeller (Norway)

    2015-10-05

    Highlights: • 6LiBH{sub 4}–RECl{sub 3}–3LiH composites (RE = La, Er) studied for the first time. • Drastically reduced decomposition temperature (300 {sup o}C) compared to LiBH{sub 4} (>400 °C). • Partial reversibility for 6LiBH{sub 4}–LaCl{sub 3}–3LiH: (19% at 340 °C, 10 MPa). • Excellent reversibility for 6LiBH{sub 4}–ErCl{sub 3}–3LiH: (80% at 340 °C, 10 MPa). • Reversibility comparable to that obtained for pure LiBH{sub 4} (76% at 600 °C and 15.5 MPa). - Abstract: Mixtures of 6LiBH{sub 4}–RECl{sub 3}–3LiH (RE = La, Er) have been produced by mechanochemical milling and their structure, thermal decomposition and reversibility have been studied. Hydrogen desorption starts around 300 °C in both composites. Heating to 400 °C yields LaB{sub 6}, ErB{sub 4} and REH{sub 2+δ} as major decomposition products. LiBH{sub 4} is destabilized by REH{sub 2+δ} formed through decomposition of the parent borohydrides LiLa(BH{sub 4}){sub 3}Cl and Er(BH{sub 4}){sub 3}, respectively, and its hydrogen release temperature is reduced by 100 °C as compared to pure ball-milled LiBH{sub 4}. The lanthanum-containing composite releases 4.2 wt.% H between 300 and 350 °C and shows a limited reversibility of ∼20% (340 °C, 10 MPa) probably due to hydrogen uptake by some amorphous boron-containing phases. For 6LiBH{sub 4}–ErCl{sub 3}–3LiH about 3 wt.% H is evolved up to 400 °C. Desorption against 0.5 MPa backpressure results in an increased reversibility (∼80%) as compared to vacuum (∼66%). Rehydrogenation (340 °C, 10 MPa) shows the formation of ErH{sub 3} and LiBH{sub 4} at drastically reduced conditions compared to pure LiBH{sub 4} (>400 °C, >10 MPa)

  11. Utilization of acetone-butanol-ethanol-water mixture obtained from biomass fermentation as renewable feedstock for hydrogen production via steam reforming: Thermodynamic and energy analyses.

    Science.gov (United States)

    Kumar, Brajesh; Kumar, Shashi; Sinha, Shishir; Kumar, Surendra

    2018-08-01

    A thermodynamic equilibrium analysis on steam reforming process to utilize acetone-butanol-ethanol-water mixture obtained from biomass fermentation as biorenewable fuel has been performed to produce clean energy carrier H 2 via non-stoichiometric approach namely Gibbs free energy minimization method. The effect of process variables such as temperature (573-1473 K), pressure (1-10 atm), and steam/fuel molar feed ratio (F ABE  = 5.5-12) have been investigated on equilibrium compositions of products, H 2 , CO, CO 2 , CH 4 and solid carbon. The best suitable conditions for maximization of desired product H 2 , suppression of CH 4 , and inhibition of solid carbon are 973 K, 1 atm, steam/fuel molar feed ratio = 12. Under these conditions, the maximum molar production of hydrogen is 8.35 with negligible formation of carbon and methane. Furthermore, the energy requirement per mol of H 2 (48.96 kJ), thermal efficiency (69.13%), exergy efficiency (55.09%), exergy destruction (85.36 kJ/mol), and generated entropy (0.29 kJ/mol.K) have been achieved at same operating conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Effect of toluene concentration and hydrogen peroxide on Pseudomonas plecoglossicida cometabolizing mixture of cis-DCE and TCE in soil slurry.

    Science.gov (United States)

    Li, Junhui; Lu, Qihong; de Toledo, Renata Alves; Lu, Ying; Shim, Hojae

    2015-12-01

    An indigenous Pseudomonas sp., isolated from the regional contaminated soil and identified as P. plecoglossicida, was evaluated for its aerobic cometabolic removal of cis-1,2-dichloroethylene (cis-DCE) and trichloroethylene (TCE) using toluene as growth substrate in a laboratory-scale soil slurry. The aerobic simultaneous bioremoval of the cis-DCE/TCE/toluene mixture was studied under different conditions. Results showed that an increase in toluene concentration level from 300 to 900 mg/kg prolonged the lag phase for the bacterial growth, while the bioremoval extent for cis-DCE, TCE, and toluene declined as the initial toluene concentration increased. In addition, the cometabolic bioremoval of cis-DCE and TCE was inhibited by the presence of hydrogen peroxide as the additional oxygen source, while the bioremoval of toluene (900 mg/kg) was enhanced after 9 days of incubation. The subsequent addition of toluene did not improve the cometabolic bioremoval of cis-DCE and TCE. The obtained results would help to enhance the applicability of bioremediation technology to the mixed waste contaminated sites.

  13. The energy dependence of selective hydrogen atom abstraction by H(D) atoms in the photolysis of neopentane - ethane mixtures at 77 K

    International Nuclear Information System (INIS)

    Miyazaki, T.; Fueki, K.

    1980-01-01

    Selective hydrogen - atom - abstraction reaction by H or D atom has been studied in a neo C 5 H 12 - C 2 H 6 (less than 1 mol %) mixture at 77 K by ESR spectroscopy. The H (or D) atom produced by the photolysis of HI (or DI) reacts with neo - C 2 H 12 and C 2 H 6 to form neo - C 5 H 11 and C 2 H 5 radicals. In order to obtain H atoms with different kinetic energies, the photolysis was performed with different lights of 313, 254 and 229 nm. The selective formation of the C 2 H 5 radical by the reaction of the H (or D) atom with C 2 H 6 becomes more effective with the decrease in the energy of the H (or D) atom. The formation of the neo - C 5 H 11 radical by the reaction of the H (or D) atom with neo - C 2 H 12 becomes more effective with the increase in the energy of the H (or D) atom. (A.R.H.) [pt

  14. Optimization of strawberry disinfection by fogging of a mixture of peracetic acid and hydrogen peroxide based on microbial reduction, color and phytochemicals retention.

    Science.gov (United States)

    Van de Velde, Franco; Vaccari, María Celia; Piagentini, Andrea Marcela; Pirovani, María Élida

    2016-09-01

    The fogging of strawberries using a environmentally friendly sanitizer mixture of peracetic acid (5%) and hydrogen peroxide (20%) was performed in a model chamber and modeled as a function of the concentration (3.4, 20.0, 60.0, 100.0 and 116.6 µL sanitizer L(-) (1) air chamber) and the treatment time (5.7, 15.0, 37.5, 60.0 and 69.3 min). The sanitizer fogging was adequate for reducing total mesophilic microbial and yeasts and moulds counts of fruits until seven days of storage at 2℃. However, sanitizer oxidant properties adversely affected the content of total anthocyanins, total phenolics, vitamin C, and antioxidant capacity to various degrees, with some deleterious changes in the fruits color, depending on the fogging conditions. A multiple numeric response optimization was developed based on 2.0 log microbiological reduction, maximum phytochemicals and antioxidant capacity retentions, with no changes in the fruits color, being the optimal fogging conditions achieved: 10.1 µL sanitizer L(-1) air chamber and 29.6 min. The fogging of strawberries at these conditions may represent a promising postharvest treatment option for extending their shelf-life without affecting their sensory quality and bioactive properties. © The Author(s) 2016.

  15. Permeation of hydrogen at low pressures through stainless steel and implications for tritium control in fusion reactor systems

    International Nuclear Information System (INIS)

    Axtmann, R.C.; Johnson, E.F.; Kuehler, C.W.

    1976-01-01

    New experimental data on the permeation of hydrogen through stainless steel indicate that at driving pressures below 10 -2 torr, the permeation rate is linearly dependent on the driving pressure. A possible consequence is that the permeation rates of hydrogenic species in fusion reactor systems might be much lower than those reported in contemporary conceptual design studies which assume that the rates are dependent on the square root of the driving pressure. The important implications of these low permeation rates are: (1) tritium losses to the environment may be more dependent on ordinary leaks from equipment than on permeation to the steam cycle; (2) recovery of tritium from breeding blankets via permeation windows may be impracticable; and (3) recovery of tritium from breeding blankets not dependent on permeation windows may be simplified by the possibility of operating at much higher average tritium concentrations in the blanket and cooling systems

  16. An investigation of the opacity of high-Z mixture and implications for inertial confinement fusion hohlraum design

    International Nuclear Information System (INIS)

    Wang, P.; MacFarlane, J.J.; Orzechowski, T.J.

    1997-01-01

    We use an unresolved transition array model to investigate the opacities of high-Z materials and their mixtures which are of interest to indirect-drive inertial confinement fusion hohlraum design. In particular, we report on calculated opacities for pure Au, Gd, and Sm, as well as Au endash Sm and Au endash Gd mixtures. Our results indicate that mixtures of Au endash Gd and Au endash Sm can produce a significant enhancement in the Rosseland mean opacity. Radiation hydrodynamics simulations of Au radiation burnthrough are also presented, and compared with NOVA experimental data. copyright 1997 American Institute of Physics

  17. Ab initio calculation of the sound velocity of dense hydrogen: implications for models of Jupiter

    NARCIS (Netherlands)

    Alavi, A.; Parrinello, M.; Frenkel, D.

    1995-01-01

    First-principles molecular dynamics simulations were used to calculate the sound velocity of dense hydrogen, and the results were compared with extrapolations of experimental data that currently conflict with either astrophysical models or data obtained from recent global oscillation measurements of

  18. Low-level hydrogen peroxide generation by unbleached cotton nonwovens: implications for wound healing applications

    Science.gov (United States)

    Greige cotton is an intact plant fiber. The cuticle and primary cell wall near the outer surface of the cotton fiber contains pectin, peroxidases, superoxide dismutase (SOD), and trace metals, which are associated with hydrogen peroxide (H2O2) generation during cotton fiber development. The compon...

  19. Hydrogen Sulphide Corrosion of Carbon and Stainless Steel Alloys Immersed in Mixtures of Renewable Fuel Sources and Tested Under Co-processing Conditions

    Directory of Open Access Journals (Sweden)

    Gergely András

    2016-10-01

    Full Text Available In accordance with modern regulations and directives, the use of renewable biomass materials as precursors for the production of fuels for transportation purposes is to be strictly followed. Even though, there are problems related to processing, storage and handling in wide range of subsequent uses, since there must be a limit to the ratio of biofuels mixed with mineral raw materials. As a key factor with regards to these biomass sources pose a great risk of causing multiple forms of corrosion both to metallic and non-metallic structural materials. To assess the degree of corrosion risk to a variety of engineering alloys like low-carbon and stainless steels widely used as structural metals, this work is dedicated to investigating corrosion rates of economically reasonable engineering steel alloys in mixtures of raw gas oil and renewable biomass fuel sources under typical co-processing conditions. To model a desulphurising refining process, corrosion tests were carried out with raw mineral gasoline and its mixture with used cooking oil and animal waste lard in relative quantities of 10% (g/g. Co-processing was simulated by batch-reactor laboratory experiments. Experiments were performed at temperatures between 200 and 300ºC and a pressure in the gas phase of 90 bar containing 2% (m3/m3 hydrogen sulphide. The time span of individual tests were varied between 1 and 21 days so that we can conclude about changes in the reaction rates against time exposure of and extrapolate for longer periods of exposure. Initial and integral corrosion rates were defined by a weight loss method on standard size of coupons of all sorts of steel alloys. Corrosion rates of carbon steels indicated a linear increase with temperature and little variation with composition of the biomass fuel sources. Apparent activation energies over the first 24-hour period remained moderate, varying between 35.5 and 50.3 kJ mol−1. Scales developed on carbon steels at higher

  20. Large entropy derived from low-frequency vibrations and its implications for hydrogen storage

    Science.gov (United States)

    Wang, Xiaoxia; Chen, Hongshan

    2018-02-01

    Adsorption and desorption are driven by the energy and entropy competition, but the entropy effect is often ignored in hydrogen storage and the optimal adsorption strength for the ambient storage is controversial in the literature. This letter investigated the adsorption states of the H2 molecule on M-B12C6N6 (M = Li, Na, Mg, Ca, and Sc) and analyzed the correlation among the zero point energy (ZPE), the entropy change, and the adsorption energy and their effects on the delivery capacities. The ZPE has large correction to the adsorption energy due to the light mass of hydrogen. The computations show that the potential energies along the spherical surface centered at the alkali metals are very flat and it leads to large entropy (˜70 J/mol.K) of the adsorbed H2 molecules. The entropy change can compensate the enthalpy change effectively, and the ambient storage can be realized with relatively weak adsorption of ΔH = -12 kJ/mol. The results are encouraging and instructive for the design of hydrogen storage materials.

  1. Boiling points of halogenated ethanes: an explanatory model implicating weak intermolecular hydrogen-halogen bonding.

    Science.gov (United States)

    Beauchamp, Guy

    2008-10-23

    This study explores via structural clues the influence of weak intermolecular hydrogen-halogen bonds on the boiling point of halogenated ethanes. The plot of boiling points of 86 halogenated ethanes versus the molar refraction (linked to polarizability) reveals a series of straight lines, each corresponding to one of nine possible arrangements of hydrogen and halogen atoms on the two-carbon skeleton. A multiple linear regression model of the boiling points could be designed based on molar refraction and subgroup structure as independent variables (R(2) = 0.995, standard error of boiling point 4.2 degrees C). The model is discussed in view of the fact that molar refraction can account for approximately 83.0% of the observed variation in boiling point, while 16.5% could be ascribed to weak C-X...H-C intermolecular interactions. The difference in the observed boiling point of molecules having similar molar refraction values but differing in hydrogen-halogen intermolecular bonds can reach as much as 90 degrees C.

  2. Improvement of performance and reduction of pollutant emissions of a four-stroke spark ignition engine fuelled with a mixture of hydrogen and methane as a supplementary fuel to alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Al-Bagdhadi, M.A.-R.S. [University of Babylon (Iraq). College of Engineering

    2004-05-01

    Owing to the energy crisis and pollution problems of today, investigations have concentrated on decreasing fuel consumption and on lowering the concentration of toxic components in combustion products by using non-petroleum, renewable, sustainable and non-polluting fuels. While conventional energy sources such as natural gas, oil and coal are non-renewable, hydrogen and alcohol can be coupled to renewable and sustainable energy sources. The usage of a mixture of hydrogen and methane as a supplementary fuel to an alcohol-air mixture for spark ignition engines results in a considerable improvement in engine performance and in the reduction of the toxic components in exhaust gases in comparison with the conventional spark ignition gasoline engine. In tests, the gas comprising 40 per cent H, and 60 per cent CH{sub 4} by volume was added to alcohol as 0, 2, 4, 6, 8, 10 and 12 per cent by mass. Operating test results for a range of compression ratio (CR) and equivalent ratio are presented. Gasoline fuel was used as a basis for comparison. The important improvement in methane addition reduced the specific fuel consumption (s.f.c.) and CO emission of alcohol engines. The performance of the engine is enhanced when relatively small amounts of hydrogen are present with methane. This improvement in performance, which is especially pronounced at operational equivalence ratios that are much leaner than the stoichiometric value, can be attributed largely to the faster and cleaner burning characteristics of hydrogen in comparison with methane or alcohol. Moreover, the addition of hydrogen decreases the s.f.c. of the engine. The possibility of an engine power quality adjustment has also been studied. (author)

  3. The impact of natural gas/hydrogen mixtures on the performance of end-use equipment : Interchangeability analysis for domestic appliances

    NARCIS (Netherlands)

    de Vries, Harmen; Mokhov, Anatoli V.; Levinsky, Howard B.

    2017-01-01

    The addition of hydrogen derived from renewable power to the natural gas network is being promoted as a viable means of storing excess wind and solar energy. However, the changes in combustion properties of the natural gas upon hydrogen addition can impact the performance of the end-use equipment

  4. Hydrogen-bearing iron peroxide and its implications to the deep Earth

    Science.gov (United States)

    Liu, J.; Hu, Q.; Kim, D. Y.; Wu, Z.; Wang, W.; Alp, E. E.; Yang, L.; Xiao, Y.; Meng, Y.; Chow, P.; Greenberg, E.; Prakapenka, V. B.; Mao, H. K.; Mao, W. L.

    2017-12-01

    Hydrous materials subducted into the deep mantle may play a significant role in the geophysical and geochemical processes of the lower mantle through geological time, but their roles have not become clear yet in the region. Hydrogen-bearing iron peroxide (FeO2Hx) was recently discovered to form through dehydrogenation of goethite (e.g., FeOOH) and the reaction between hematite (Fe2O3) and water under deep lower mantle conditions. We conducted synchrotron Mössbauer, X-ray absorption, and X-ray emission spectroscopy measurements to investigate the electronic spin and valence states of iron in hydrogen-bearing iron peroxide (FeO2Hx) in-situ at high pressures. Combined with theoretical calculations and other high-pressure experiments (i.e., nuclear resonant inelastic x-ray scattering spectroscopy and X-ray diffraction coupled with laser-heated diamond-anvil cell techniques), we find that the intriguing properties of FeO2Hx could shed light on the origin of a number of the observed geochemical and geophysical anomalies in the deep Earth.

  5. THE HYDROGEN EPOCH OF REIONIZATION ARRAY DISH. I. BEAM PATTERN MEASUREMENTS AND SCIENCE IMPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Neben, Abraham R.; Hewitt, Jacqueline N.; Ewall-Wice, Aaron [MIT Kavli Institute, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Bradley, Richard F. [Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA 22904 (United States); DeBoer, David R.; Parsons, Aaron R.; Ali, Zaki S.; Cheng, Carina; Patra, Nipanjana; Dillon, Joshua S. [Department of Astronomy, University of California, Berkeley, CA (United States); Aguirre, James E.; Kohn, Saul A. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA (United States); Thyagarajan, Nithyanandan; Bowman, Judd; Jacobs, Daniel C. [Arizona State University, School of Earth and Space Exploration, Tempe, AZ 85287 (United States); Dickenson, Roger; Doolittle, Phillip; Egan, Dennis; Hedrick, Mike; Klima, Patricia J. [National Radio Astronomy Observatory, Charlottesville, VA (United States); and others

    2016-08-01

    The Hydrogen Epoch of Reionization Array (HERA) is a radio interferometer aiming to detect the power spectrum of 21 cm fluctuations from neutral hydrogen from the epoch of reionization (EOR). Drawing on lessons from the Murchison Widefield Array and the Precision Array for Probing the EOR, HERA is a hexagonal array of large (14 m diameter) dishes with suspended dipole feeds. The dish not only determines overall sensitivity, but also affects the observed frequency structure of foregrounds in the interferometer. This is the first of a series of four papers characterizing the frequency and angular response of the dish with simulations and measurements. In this paper, we focus on the angular response (i.e., power pattern), which sets the relative weighting between sky regions of high and low delay and thus apparent source frequency structure. We measure the angular response at 137 MHz using the ORBCOMM beam mapping system of Neben et al. We measure a collecting area of 93 m{sup 2} in the optimal dish/feed configuration, implying that HERA-320 should detect the EOR power spectrum at z ∼ 9 with a signal-to-noise ratio of 12.7 using a foreground avoidance approach with a single season of observations and 74.3 using a foreground subtraction approach. Finally, we study the impact of these beam measurements on the distribution of foregrounds in Fourier space.

  6. THE HYDROGEN EPOCH OF REIONIZATION ARRAY DISH. I. BEAM PATTERN MEASUREMENTS AND SCIENCE IMPLICATIONS

    International Nuclear Information System (INIS)

    Neben, Abraham R.; Hewitt, Jacqueline N.; Ewall-Wice, Aaron; Bradley, Richard F.; DeBoer, David R.; Parsons, Aaron R.; Ali, Zaki S.; Cheng, Carina; Patra, Nipanjana; Dillon, Joshua S.; Aguirre, James E.; Kohn, Saul A.; Thyagarajan, Nithyanandan; Bowman, Judd; Jacobs, Daniel C.; Dickenson, Roger; Doolittle, Phillip; Egan, Dennis; Hedrick, Mike; Klima, Patricia J.

    2016-01-01

    The Hydrogen Epoch of Reionization Array (HERA) is a radio interferometer aiming to detect the power spectrum of 21 cm fluctuations from neutral hydrogen from the epoch of reionization (EOR). Drawing on lessons from the Murchison Widefield Array and the Precision Array for Probing the EOR, HERA is a hexagonal array of large (14 m diameter) dishes with suspended dipole feeds. The dish not only determines overall sensitivity, but also affects the observed frequency structure of foregrounds in the interferometer. This is the first of a series of four papers characterizing the frequency and angular response of the dish with simulations and measurements. In this paper, we focus on the angular response (i.e., power pattern), which sets the relative weighting between sky regions of high and low delay and thus apparent source frequency structure. We measure the angular response at 137 MHz using the ORBCOMM beam mapping system of Neben et al. We measure a collecting area of 93 m 2 in the optimal dish/feed configuration, implying that HERA-320 should detect the EOR power spectrum at z ∼ 9 with a signal-to-noise ratio of 12.7 using a foreground avoidance approach with a single season of observations and 74.3 using a foreground subtraction approach. Finally, we study the impact of these beam measurements on the distribution of foregrounds in Fourier space.

  7. Sensitivity of hydrogen bonds of DNA and RNA to hydration, as gauged by 1JNH measurements in ethanol-water mixtures

    International Nuclear Information System (INIS)

    Manalo, Marlon N.; Kong Xiangming; LiWang, Andy

    2007-01-01

    Hydrogen-bond lengths of nucleic acids are (1) longer in DNA than in RNA, and (2) sequence dependent. The physicochemical basis for these variations in hydrogen-bond lengths is unknown, however. Here, the notion that hydration plays a significant role in nucleic acid hydrogen-bond lengths is tested. Watson-Crick N1...N3 hydrogen-bond lengths of several DNA and RNA duplexes are gauged using imino 1 J NH measurements, and ethanol is used as a cosolvent to lower water activity. We find that 1 J NH values of DNA and RNA become less negative with added ethanol, which suggests that mild dehydration reduces hydrogen-bond lengths even as the overall thermal stabilities of these duplexes decrease. The 1 J NH of DNA are increased in 8 mol% ethanol to those of RNA in water, which suggests that the greater hydration of DNA plays a significant role in its longer hydrogen bonds. The data also suggest that ethanol-induced dehydration is greater for the more hydrated G:C base pairs and thereby results in greater hydrogen-bond shortening than for the less hydrated A:T/U base pairs of DNA and RNA

  8. Conjugation of cytochrome c with hydrogen titanate nanotubes: novel conformational state with implications for apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Moumita; Mazumdar, Shyamalava [Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Chatterjee, Sriparna; Das, Tanmay; Bhattacharyya, Somnath; Ayyub, Pushan, E-mail: somnath@tifr.res.in, E-mail: pushan@tifr.res.in, E-mail: shyamal@tifr.res.in [Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)

    2011-10-14

    We show that hydrogen titanate (H{sub 2}Ti{sub 3}O{sub 7}) nanotubes form strongly associated reversible nano-bio-conjugates with the vital respiratory protein, cytochrome c. Resonance Raman spectroscopy along with direct electrochemical studies indicate that in this nano-bio-conjugate, cytochrome c exists in an equilibrium of two conformational states with distinctly different formal redox potentials and coordination geometries of the heme center. The nanotube-conjugated cytochrome c also showed enhanced peroxidase activity similar to the membrane-bound protein that is believed to be an apoptosis initiator. This suggests that such a nanotube-cytochrome c conjugate may be a good candidate for cancer therapy applications.

  9. Neutral Hydrogen Structures Trace Dust Polarization Angle: Implications for Cosmic Microwave Background Foregrounds.

    Science.gov (United States)

    Clark, S E; Hill, J Colin; Peek, J E G; Putman, M E; Babler, B L

    2015-12-11

    Using high-resolution data from the Galactic Arecibo L-Band Feed Array HI (GALFA-Hi) survey, we show that linear structure in Galactic neutral hydrogen (Hi) correlates with the magnetic field orientation implied by Planck 353 GHz polarized dust emission. The structure of the neutral interstellar medium is more tightly coupled to the magnetic field than previously known. At high Galactic latitudes, where the Planck data are noise dominated, the Hi data provide an independent constraint on the Galactic magnetic field orientation, and hence the local dust polarization angle. We detect strong cross-correlations between template maps constructed from estimates of dust intensity combined with either Hi-derived angles, starlight polarization angles, or Planck 353 GHz angles. The Hi data thus provide a new tool in the search for inflationary gravitational wave B-mode polarization in the cosmic microwave background, which is currently limited by dust foreground contamination.

  10. Impact of Microplastic Beads and Fibers on Waterflea (Ceriodaphnia dubia) Survival, Growth, and Reproduction: Implications of Single and Mixture Exposures.

    Science.gov (United States)

    Ziajahromi, Shima; Kumar, Anupama; Neale, Peta A; Leusch, Frederic D L

    2017-11-21

    There is limited knowledge regarding the adverse effects of wastewater-derived microplastics, particularly fibers, on aquatic biota. In this study, we examined the acute (48 h) and chronic (8 d) effects of microplastic polyester fibers and polyethylene (PE) beads on freshwater zooplankton Ceriodaphnia dubia. We also assessed the acute response of C. dubia to a binary mixture of microplastic beads and fibers for the first time. Acute exposure to fibers and PE beads both showed a dose-dependent effect on survival. An equitoxic binary mixture of beads and fibers resulted in a toxic unit of 1.85 indicating less than additive effects. Chronic exposure to lower concentrations did not significantly affect survival of C. dubia, but a dose-dependent effect on growth and reproduction was observed. Fibers showed greater adverse effects than PE beads. While ingestion of fibers was not observed, scanning electron microscopy showed carapace and antenna deformities after exposure to fibers, with no deformities observed after exposure to PE beads. While much of the current research has focused on microplastic beads, our study shows that microplastic fibers pose a greater risk to C. dubia, with reduced reproductive output observed at concentrations within an order of magnitude of reported environmental levels.

  11. Rheological behavior of water-ash mixtures from Sakurajima and Ontake volcanoes: implications for lahar flow dynamics

    Science.gov (United States)

    Kurokawa, Aika K.; Ishibashi, Hidemi; Miwa, Takahiro; Nanayama, Futoshi

    2018-06-01

    Lahars represent one of the most serious volcanic hazards, potentially causing severe damage to the surrounding environment, not only immediately after eruption but also later due to rainfall or snowfall. The flow of a lahar is governed by volcanic topography and its rheological behavior, which is controlled by its volume, microscale properties, and the concentration of particles. However, the effects of particle properties on the rheology of lahars are poorly understood. In this study, viscosity measurements were performed on water-ash mixtures from Sakurajima and Ontake volcanoes. Samples from Sakurajima show strong and simple shear thinning, whereas those from Ontake show viscosity fluctuations and a transition between shear thinning and shear thickening. Particle analysis of the volcanic ash together with a theoretical analysis suggests that the rheological difference between the two types of suspension can be explained by variations in particle size distribution and shape. In particular, to induce the complex rheology of the Ontake samples, coexistence of two particle size groups may be required since two independent behaviors, one of which follows the streamline (Stokes number St << 1, inertial number I < 0.001) and the other shows a complicated motion ( St 1, I 0.001), compete against each other. The variations in the spatial distribution of polydisperse particles, and the time dependence of this feature which generates apparent rheological changes, indicate that processes related to microscale particle heterogeneities are important in understanding the flow dynamics of lahars and natural polydisperse granular-fluid mixtures in general.

  12. Hydrogen absorption mechanisms and hydrogen interactions - defects: implications to stress corrosion of nickel based alloys in pressurized water reactors primary water

    International Nuclear Information System (INIS)

    Jambon, F.

    2012-01-01

    Since the late 1960's, a special form of stress corrosion cracking (SCC) has been identified for Alloy 600 exposed to pressurized water reactors (PWR) primary water: intergranular cracks develop during the alloy exposure, leading, progressively, to the complete ruin of the structure, and to its replacement. The main goal of this study is therefore to evaluate in which proportions the hydrogen absorbed by the alloy during its exposure to the primary medium can be responsible for SCC crack initiation and propagation. This study is aimed at better understanding of the hydrogen absorption mechanism when a metallic surface is exposed to a passivating PWR primary medium. A second objective is to characterize the interactions of the absorbed hydrogen with the structural defects of the alloy (dislocations, vacancies...) and evaluate to what extent these interactions can have an embrittling effect in relation with SCC phenomenon. Alloy 600-like single-crystals were exposed to a simulated PWR medium where the hydrogen atoms of water or of the pressuring hydrogen gas were isotopically substituted with deuterium, used as a tracer. Secondary ion mass spectrometry depth-profiling of deuterium was performed to characterize the deuterium absorption and localization in the passivated alloy. The results show that the hydrogen absorption during the exposure of the alloy to primary water is associated with the water molecules dissociation during the oxide film build-up. In an other series of experiments, structural defects were created in recrystallized samples, and finely characterized by positron annihilation spectroscopy and transmission electron microscopy, before or after the introduction of cathodic hydrogen. These analyses exhibited a strong hydrogen/defects interaction, evidenced by their structural reorganization under hydrogenation (coalescence, migrations). However, thermal desorption spectroscopy analyses indicated that these interactions are transitory, and dependent on

  13. Radiation Effects in Hydrogen-Laden Porous Water Ice Films: Implications for Interstellar Ices

    Science.gov (United States)

    Raut, Ujjwal; Baragiola, Raul; Mitchell, Emma; Shi, Jianming

    H _{2} is the dominant gas in the dense clouds of the interstellar medium (ISM). At densities of 10 (5) cm (-3) , an H _{2} molecule arrives at the surface of a 0.1 mum-sized, ice-covered dust grain once every few seconds [1]. At 10 K, H _{2} can diffuse into the pores of the ice mantle and adsorb at high-energy binding sites, loading the ice with hydrogen over the lifetime of the cloud. These icy grains are also impacted by galactic cosmic rays and stellar winds (in clouds with embedded protostar). Based on the available cosmic proton flux spectrum [2], we estimate a small impact rate of nearly 1 hit per year on a 0.1 μm sized grain, or 10 (-7) times the impact frequency of the neutral H _{2}. The energy deposited by such impacts can release the adsorbed H _{2} into the gas phase (impact desorption or sputtering). Recently, we have reported on a new process of ion-induced enhanced adsorption, where molecules from the gas phase are incorporated into the film when irradiation is performed in the presence of ambient gas [3]. The interplay between ion-induced ejection and adsorption can be important in determining the gas-solid balance in the ISM. To understand the effects of cosmic rays/stellar winds impacts on interstellar ice immersed in H _{2} gas, we have performed irradiation of porous amorphous ice films loaded with H _{2} through co-deposition or adsorption following growth. The irradiations were performed with 100 keV H (+) using fluxes of 10 (10) -10 (12) H (+) cm (-2) s (-1) at 7 K, in presence of ambient H _{2} at pressures ranging from 10 (-5) to 10 (-8) Torr. Our initial results show a net loss in adsorbed H _{2} during irradiation, from competing ion-induced ejection and adsorption. The H _{2} loss per ion decreases exponentially with fluence, with a cross-section of 10 (-13) cm (2) . In addition to hydrogen removal, irradiation also leads to trapping of H _{2} in the ice film, from closing of the pores during irradiation [4]. As a result, 2.6 percent

  14. High capacity hydrogen storage nanocomposite materials

    Science.gov (United States)

    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.

  15. Improvement of performance and reduction of pollutant emission of a four stroke spark ignition engine fueled with hydrogen-gasoline fuel mixture

    Energy Technology Data Exchange (ETDEWEB)

    Al-Baghdadi, Maher Abdul-Resul Sadiq; Al-Janabi, Haroun Abdul-Kadim Shahad [Babylon Univ., Dept. of Mechanical Engineering, Babylon (Iraq)

    2000-07-01

    The effect of the amount of hydrogen/ethyl alcohol addition on the performance and pollutant emissions of a four stroke spark ignition engine has been studied. A detailed model to simulate a four stroke cycle of a spark ignition engine fueled with hydrogen-ethyl alcohol-gasoline has been used to study the effect of hydrogen and ethyl alcohol blending on the thermodynamic cycle of the engine. The results of the study show that all engine performance parameters have been improved when operating the gasoline S.I.E. with dual addition of hydrogen and ethyl alcohol. It has been found that 4% of hydrogen and 30% of ethyl alcohol blending causes a 49% reduction in CO emission, a 39% reduction in NO{sub x} emission, a 49% reduction in specific fuel consumption and increases in the thermal efficiency and output power by 5 and 4%, respectively. When ethyl alcohol is increased over 30%, it causes unstable engine operation which can be related to the fact that the fuel is not vaporised, and this causes a reduction in both the brake power and efficiency. (Author)

  16. An experimental approach aiming the production of a gas mixture composed of hydrogen and methane from biomass as natural gas substitute in industrial applications.

    Science.gov (United States)

    Kraussler, Michael; Schindler, Philipp; Hofbauer, Hermann

    2017-08-01

    This work presents an experimental approach aiming the production of a gas mixture composed of H 2 and CH 4 , which should serve as natural gas substitute in industrial applications. Therefore, a lab-scale process chain employing a water gas shift unit, scrubbing units, and a pressure swing adsorption unit was operated with tar-rich product gas extracted from a commercial dual fluidized bed biomass steam gasification plant. A gas mixture with a volumetric fraction of about 80% H 2 and 19% CH 4 and with minor fractions of CO and CO 2 was produced by employing carbon molecular sieve as adsorbent. Moreover, the produced gas mixture had a lower heating value of about 15.5MJ·m -3 and a lower Wobbe index of about 43.4MJ·m -3 , which is similar to the typical Wobbe index of natural gas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Geographic variation of strontium and hydrogen isotopes in avian tissue: implications for tracking migration and dispersal.

    Directory of Open Access Journals (Sweden)

    Megan J Sellick

    Full Text Available Isotopes can provide unique solutions to fundamental problems related to the ecology and evolution of migration and dispersal because prior movements of individuals can theoretically be tracked from tissues collected from a single capture. However, there is still remarkably little information available about how and why isotopes vary in wild animal tissues, especially over large spatial scales.Here, we describe variation in both stable-hydrogen (deltaD(F and strontium ((87Sr/(86Sr(F isotopic compositions in the feathers of a migratory songbird, the Tree Swallow (Tachycineta bicolor, across 18 sampling sites in North America and then examine potential mechanisms driving this variation. We found that deltaD(F was correlated with latitude of the sampling site, whereas (87Sr/(86Sr(F was correlated with longitude. deltaD(F was related to deltaD of meteoric waters where molting occurred and (87Sr/(86Sr(F was influenced primarily by the geology in the area where feathers were grown. Using simulation models, we then assessed the utility of combining both markers to estimate the origin of individuals. Using 13 geographic regions, we found that the number of individuals correctly assigned to their site of origin increased from less than 40% using either deltaD or (87Sr/(86Sr alone to 74% using both isotopes.Our results suggest that these isotopes have the potential to provide predictable and complementary markers for estimating long-distance animal movements. Combining isotopes influenced by different global-scale processes may allow researchers to link the population dynamics of animals across large geographic ranges.

  18. Dewetting acrylic polymer films with water/propylene carbonate/surfactant mixtures - implications for cultural heritage conservation.

    Science.gov (United States)

    Baglioni, M; Montis, C; Brandi, F; Guaragnone, T; Meazzini, I; Baglioni, P; Berti, D

    2017-09-13

    The removal of hydrophobic polymer films from surfaces is one of the top priorities of modern conservation science. Nanostructured fluids containing water, good solvents for polymers, either immiscible or partially miscible with water, and surfactants have been used in the last decade to achieve controlled removal. The dewetting of the polymer film is often an essential step to achieve efficient removal; however, the role of the surfactant throughout the process is yet to be fully understood. We report on the dewetting of a methacrylate/acrylate copolymer film induced by a ternary mixture of water, propylene carbonate (PC) and C 9-11 E 6 , a nonionic alcohol ethoxylate surfactant. The fluid microstructure was characterised through small angle X-ray scattering and the interactions between the film and water, water/PC and water/PC/C 9-11 E 6 , were monitored through confocal laser-scanning microscopy (CLSM) and analised both from a thermodynamic and a kinetic point of view. The presence of a surfactant is a prerequisite to induce dewetting of μm-thick films at room temperature, but it is not a thermodynamic driver. The amphiphile lowers the interfacial energy between the phases and favors the loss of adhesion of the polymer on glass, decreasing, in turn, the activation energy barrier, which can be overcome by the thermal fluctuations of polymer film stability, initiating the dewetting process.

  19. Determination of local concentration of H2O molecules and gas temperature in the process of hydrogen – oxygen gas mixture heating by means of linear and nonlinear laser spectroscopy

    International Nuclear Information System (INIS)

    Kozlov, D N; Kobtsev, V D; Stel'makh, O M; Smirnov, Valery V; Stepanov, E V

    2013-01-01

    Employing the methods of linear absorption spectroscopy and nonlinear four-wave mixing spectroscopy using laserinduced gratings we have simultaneously measured the local concentrations of H 2 O molecules and the gas temperature in the process of the H 2 – O 2 mixture heating. During the measurements of the deactivation rates of pulsed-laser excited singlet oxygen O 2 (b 1 Σ + g ) in collisions with H 2 in the range 294 – 850 K, the joint use of the two methods made it possible to determine the degree of hydrogen oxidation at a given temperature. As the mixture is heated, H 2 O molecules are formed by 'dark' reactions of H 2 with O 2 in the ground state. The experiments have shown that the measurements of tunable diode laser radiation absorption along an optical path through the inhomogeneously heated gas mixture in a cell allows high-accuracy determination of the local H 2 O concentration in the O 2 laser excitation volume, if the gas temperature in this volume is known. When studying the collisional deactivation of O 2 (b 1 Σ + g ) molecules, the necessary measurements of the local temperature can be implemented using laser-induced gratings, arising due to spatially periodic excitation of O 2 (X 3 Σ - g ) molecules to the b 1 Σ + g state by radiation of the pump laser of the four-wave mixing spectrometer. (laser spectroscopy)

  20. Hydrogen Peroxide Cycling in Acidic Geothermal Environments and Potential Implications for Oxidative Stress

    Science.gov (United States)

    Mesle, M.; Beam, J.; Jay, Z.; Bodle, B.; Bogenschutz, E.; Inskeep, W.

    2014-12-01

    Hydrogen peroxide (H2O2) may be produced in natural waters via photochemical reactions between dissolved oxygen, organic carbon and light. Other reactive oxygen species (ROS) such as superoxide and hydroxyl radicals are potentially formed in environments with high concentrations of ferrous iron (Fe(II), ~10-100 μM) by reaction between H2O2 and Fe(II) (i.e., Fenton chemistry). Thermophilic archaea and bacteria inhabiting acidic iron-oxide mats have defense mechanisms against both extracellular and intracellular peroxide, such as peroxiredoxins (which can degrade H2O2) and against other ROS, such as superoxide dismutases. Biological cycling of H2O2 is not well understood in geothermal ecosystems, and geochemical measurements combined with molecular investigations will contribute to our understanding of microbial response to oxidative stress. We measured H2O2 and other dissolved compounds (Fe(II), Fe(III), H2S, O2), as well as photon flux, pH and temperature, over time in surface geothermal waters of several acidic springs in Norris Geyser Basin, Yellowstone National Park, WY (Beowulf Spring and One Hundred Spring Plain). Iron-oxide mats were sampled in Beowulf Spring for on-going analysis of metatranscriptomes and RT-qPCR assays of specific stress-response gene transcription (e.g., superoxide dismutases, peroxiredoxins, thioredoxins, and peroxidases). In situ analyses show that H2O2 concentrations are lowest in the source waters of sulfidic systems (ca. 1 μM), and increase by two-fold in oxygenated waters corresponding to Fe(III)-oxide mat formation (ca. 2 - 3 μM). Channel transects confirm increases in H2O2 as a function of oxygenation (distance). The temporal dynamics of H2O2, O2, Fe(II), and H2S in Beowulf geothermal waters were also measured during a diel cycle, and increases in H2O2 were observed during peak photon flux. These results suggest that photochemical reactions may contribute to changes in H2O2. We hypothesize that increases in H2O2 and O2

  1. Separation of benzene from mixtures with water, methanol, ethanol, and acetone: highlighting hydrogen bonding and molecular clustering influences in CuBTC

    NARCIS (Netherlands)

    Gutiérrez-Sevillano, J.J.; Calero, S.; Krishna, R.

    2015-01-01

    Configurational-bias Monte Carlo (CBMC) simulations are used to establish the potential of CuBTC for separation of water/benzene, methanol/benzene, ethanol/benzene, and acetone/benzene mixtures. For operations under pore saturation conditions, the separations are in favor of molecules that partner

  2. Novel separation process of gaseous mixture of SO2 and O2 with ionic liquid for hydrogen production in thermochemical sulfur-iodine water splitting cycle

    International Nuclear Information System (INIS)

    Kim, Chang Soo; Gong, Gyeong Taek; Yoo, Kye Sang; Kim, Honggon; Lee, Byoung Gwon; Ahn, Byoung Sung; Jung, Kwang Deog; Lee, Ki Yong; Song, Kwang Ho

    2007-01-01

    Sulfur-Iodine cycle is the most promising thermochemical cycle for water splitting to produce hydrogen which can replace the fossil fuels in the future. As a sub-cycle in the thermochemical Sulfur-Iodine water splitting cycle, sulfuric acid (H 2 SO 4 ) decomposes into oxygen (O 2 ) and sulfur dioxide (SO 2 ) which should be separated for the recycle of SO 2 into the sulfuric acid generation reaction (Bunsen Reaction). In this study, absorption and desorption process of SO 2 by ionic liquid which is useful for the recycle of SO 2 into sulfuric acid generation reaction after sulfuric acid decomposition in the thermochemical Sulfur-Iodine cycle is investigated. At first, the operability as an absorbent for the SO 2 absorption and desorption at high temperature without the volatilization of absorbents which is not suitable for the recycle of absorbent-free SO 2 after the absorption process. The temperature range of operability is determined by TGA and DTA analysis. Most of ionic liquids investigated are applicable at high temperature desorption without volatility around 300 deg. C except [BMIm] Cl, and [BMIm] OAc which show the decomposition of ionic liquids. To evaluate the capability of SO 2 absorption, each ionic liquid is located in the absorption tube and gaseous SO 2 is bubbled into the ionic liquid. During the bubbling, the weight of the system is measured and converted into the absorbed SO 2 amount at each temperature controlled by the heater. Saturated amounts of absorbed SO 2 by ionic liquids at 50 deg. C are presented. The effect of anions for the SO 2 absorption capability is shown in the order of Cl, OAc, MeSO 3 , BF 4 , MeSO 4 , PF 6 , and HSO 4 when they are combined with [BMIm] cation. [BMIm]Cl has the largest amount of SO 2 absorbed which can be the most promising absorbent; however, from the point of operability at high temperature which includes desorption process, [BMIm]Cl is vulnerable to high temperature around 250 deg. C based on the TGA

  3. Investigation on the structure of liquid N-methylformamide-dimethylsulfoxide mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Cordeiro, Joao M.M., E-mail: cordeiro@dfq.feis.unesp.br [ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0QX (United Kingdom); Soper, Alan K. [ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0QX (United Kingdom)

    2011-03-18

    Graphical abstract: Structure of liquid NMF and DMSO mixtures investigated using a combination of neutron diffraction techniques augmented with isotopic substitution and empirical potential structure refinement simulations. Research highlights: {yields} NMF-DMSO mixture is a well-structured liquid. {yields} The liquid structure is driven by strong hydrogen bonds. {yields} There is a preference for NMF-DMSO hydrogen bonding compared to the NMF-NMF. {yields} There are very stable NMF-DMSO dimers dispersed through the liquid. {yields} The peptide structure is very well solvated in DMSO. - Abstract: The structures of liquid mixtures of N-methylformamide (NMF) and dimethyl sulfoxide (DMSO) at two concentrations (80% and 50% NMF) are investigated using a combination of neutron diffraction augmented with isotopic substitution and empirical potential structure refinement simulations. The results indicate that the NMF and DMSO molecules are hydrogen-bonded to one another with a preference for NMF-DMSO hydrogen bonding, compared to the NMF-NMF ones. The liquid is orientationally structured as a consequence of these hydrogen bonds between molecules. NMF-DMSO dimers are very stable species in the bulk of the mixture. The structure of the dimers is such that the angle between the molecular dipole moments is around 60{sup o}. The NMF molecules are well solvated in DMSO with potential implications for peptides solvation in this solvent.

  4. Investigation on the structure of liquid N-methylformamide-dimethylsulfoxide mixtures

    International Nuclear Information System (INIS)

    Cordeiro, Joao M.M.; Soper, Alan K.

    2011-01-01

    Graphical abstract: Structure of liquid NMF and DMSO mixtures investigated using a combination of neutron diffraction techniques augmented with isotopic substitution and empirical potential structure refinement simulations. Research highlights: → NMF-DMSO mixture is a well-structured liquid. → The liquid structure is driven by strong hydrogen bonds. → There is a preference for NMF-DMSO hydrogen bonding compared to the NMF-NMF. → There are very stable NMF-DMSO dimers dispersed through the liquid. → The peptide structure is very well solvated in DMSO. - Abstract: The structures of liquid mixtures of N-methylformamide (NMF) and dimethyl sulfoxide (DMSO) at two concentrations (80% and 50% NMF) are investigated using a combination of neutron diffraction augmented with isotopic substitution and empirical potential structure refinement simulations. The results indicate that the NMF and DMSO molecules are hydrogen-bonded to one another with a preference for NMF-DMSO hydrogen bonding, compared to the NMF-NMF ones. The liquid is orientationally structured as a consequence of these hydrogen bonds between molecules. NMF-DMSO dimers are very stable species in the bulk of the mixture. The structure of the dimers is such that the angle between the molecular dipole moments is around 60 o . The NMF molecules are well solvated in DMSO with potential implications for peptides solvation in this solvent.

  5. Hydrogen concentration control utilizing a hydrogen permeable membrane

    International Nuclear Information System (INIS)

    Keating, S.J. Jr.

    1976-01-01

    The concentration of hydrogen in a fluid mixture is controlled to a desired concentration by flowing the fluid through one chamber of a diffusion cell separated into two chambers by a hydrogen permeable membrane. A gradient of hydrogen partial pressure is maintained across the membrane to cause diffusion of hydrogen through the membrane to maintain the concentration of hydrogen in the fluid mixture at the predetermined level. The invention has particular utility for the purpose of injecting into and/or separating hydrogen from the reactor coolant of a nuclear reactor system

  6. Determination of cholesterol oxides in anchovies (Engraulis encrasicolus treated with a commercial mixture of citric acid, trisodium acid and hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Aniello Anastasio

    2013-02-01

    Full Text Available A new additive formulation containing hydrogen peroxide, citric acid and trisodium acid is illegally used in fishery products due its whitening and antioxidant features. Aim of this study was to evaluate the possible presence of COPs and their role as markers of illegal treatment in anchovies (Engraulis encrasicolus stored at different temperatures. Sensory analysis was also performed by the specific QIM test. The quantitative determinations (% of cholesterol oxides (COPs showed changing amounts during storage. Not always The COPs measured in the treated samples were significantly higher than control samples. Considering the volatility of hydrogen peroxide and the poor repeatability of COPs analyses, as shown in the present study, it is crucial to intensify the control by the Authorities.

  7. Comparison of Langmuir probe and multipole resonance probe measurements in argon, hydrogen, nitrogen, and oxygen mixtures in a double ICP discharge

    Science.gov (United States)

    Fiebrandt, Marcel; Oberberg, Moritz; Awakowicz, Peter

    2017-07-01

    The results of a Multipole Resonance Probe (MRP) are compared to a Langmuir probe in measuring the electron density in Ar, H2, N2, and O2 mixtures. The MRP was designed for measurements in industry processes, i.e., coating or etching. To evaluate a possible influence on the MRP measurement due to molecular gases, different plasmas with increasing molecular gas content in a double inductively coupled plasma at 5 Pa and 10 Pa at 500 W are used. The determined electron densities from the MRP and the Langmuir probe slightly differ in H2 and N2 diluted argon plasmas, but diverge significantly with oxygen. In pure molecular gas plasmas, electron densities measured with the MRP are always higher than those measured with the Langmuir Probe, in particular, in oxygen containing mixtures. The differences can be attributed to etching of the tungsten wire in the Ar:O2 mixtures and rf distortion in the pure molecular discharges. The influence of a non-Maxwellian electron energy distribution function, negative ions or secondary electron emission seems to be of no or only minor importance.

  8. Study of the selective abstration reaction of the hydrogen atom in the radiolysis and photolysis of alkane mixture at 77 K

    International Nuclear Information System (INIS)

    Guedes, S.M.L.

    1979-01-01

    The occurence of the selective abstraction reaction of the solute hydrogen atom by hydrogen atom produced during radiolysis or photolysis of the systems such as neopentane/cyclo-hexane/HI, neopentane/2,3 dimethylbutane, n-pentane/HI/cyclo-hexane and cyclo-hexane/HI/n-pentane, at 77 K is studied. Experiments have been undertaken on the kinetics nature of the active species, the H atom, during radiolysis and photolysis of the neopentane/cyclo-hexane/HI system at 77 K, presenting competitive reactions. Studies have also been made on the occurrence of the selective abstraction reaction in inverted systems, in which the concentrations of the components of a system are so much altered that the solute becomes the solvent and vice-versa, in the other system. By means of photolysis at 77 K, it has been observed that for the two systems constitued by the cyclo-hexane and n-pentane the selective abstraction reaction occurs. However, for radiolysis of that same two systems it has been observed that only the hydrogen atom abstraction reaction corresponding to the solvent occurs. (Author) [pt

  9. Grain growth kinetics of ringwoodite and majorite garnet mixtures and implications for the rheology of the transition zone

    Science.gov (United States)

    Ezad, I.; Dobson, D. P.; Brodholt, J. P.; Thomson, A.; Hunt, S.

    2017-12-01

    The grain size of the transition zone is a poorly known but important geophysical parameter. Among others, the grain size may control the rheology, seismic attenuation and radiative thermal conductivity of the mantle. However, the grain size of the transition zone minerals ringwoodite (Mg,Fe)2SiO4 and majorite garnet MgSiO3 under appropriate zone conditions is currently unknown and there are very few experiments with which to constrain it. In order to determine the grain size of the transition zone, the grain growth kinetics must be determined for a range of mantle compositions. We have, therefore, experimentally determined the grain growth kinetics of the lowermost transition zone minerals through multi anvil experiments at University College London (UCL). This is achieved through a comprehensive set of time series experiments at pressures of 21 GPa and temperatures relevant to the transition zone. We have also determined the effect of varying water content, oxygen fugacity, iron content and aluminium content also discussed by Dobson and Mariani., (2014). Our initial grain growth experiments conducted at 1200°C and 1400°C at 18 GPa show extremely slow grain growth kinetics; time series experiments extended to 105.8 seconds are unable to produce grains larger than 100 nm. This suggests that fine-grained material at the base of the transition zone will persist on geological timescales. Such small grains size suggests that diffusion creep might be the dominant deformation mechanism in this region. Reference: Dobson, D.P., Mariani, E., 2014. The kinetics of the reaction of majorite plus ferropericlase to ringwoodite: Implications for mantle upwellings crossing the 660 km discontinuity. Earth Planet. Sci. Lett. 408, 110-118. doi:10.1016/j.epsl.2014.10.009

  10. Investigation on the structure of liquid N-methylformamide-dimethylsulfoxide mixtures

    Science.gov (United States)

    Cordeiro, João M. M.; Soper, Alan K.

    2011-03-01

    The structures of liquid mixtures of N-methylformamide (NMF) and dimethyl sulfoxide (DMSO) at two concentrations (80% and 50% NMF) are investigated using a combination of neutron diffraction augmented with isotopic substitution and empirical potential structure refinement simulations. The results indicate that the NMF and DMSO molecules are hydrogen-bonded to one another with a preference for NMF-DMSO hydrogen bonding, compared to the NMF-NMF ones. The liquid is orientationally structured as a consequence of these hydrogen bonds between molecules. NMF-DMSO dimers are very stable species in the bulk of the mixture. The structure of the dimers is such that the angle between the molecular dipole moments is around 60°. The NMF molecules are well solvated in DMSO with potential implications for peptides solvation in this solvent.

  11. Synthesis of the hydride mixtures (1 - x)AlH3/xMgH2 (0 ≤ x ≤ 0.3) by ball milling and their hydrogen storage properties

    International Nuclear Information System (INIS)

    Iosub, V.; Matsunaga, T.; Tange, K.; Ishikiriyama, M.; Miwa, K.

    2009-01-01

    In an effort to thermodynamically stabilize the alane (i.e., to increase the desorption enthalpy), partial substitution of Mg for Al was investigated by ball milling the mixtures (1 - x)AlH 3 /xMgH 2 (x = 0.1, 0.2 and 0.3). Rietveld analysis of the XRD profiles showed that the cell volume of α-AlH 3 increased with the Mg substitution rate, and thereby formation of solid solutions was assumed (x ≤ 0.05). In agreement with the experimental results, theoretical calculations indicated that a hypothetical supercell structure (MgAl 15 )H 47 (x = 0.0625), which contained a hydrogen vacancy, was at least metastable. However, the effect of alane stabilization by Mg substitution for Al was not observed, either by experiment or by simulation, and only an increase in the activation energy was measured.

  12. Synthesis of nano-sized hydrogen phosphate-imprinted polymer in acetonitrile/water mixture and its use as a recognition element of hydrogen phosphate selective all-solid state potentiometric electrode.

    Science.gov (United States)

    Alizadeh, Taher; Atayi, Khalil

    2018-02-01

    Herein, a new recipe is introduced for the preparation of hydrogen phosphate ion-imprinted polymer nanoparticles (nano-IIP) in acetonitrile/water (63.5:36.5) using phosphoric acid as the template. The nano-IIP obtained was used as the recognition element of a carbon paste potentiometric sensor. The IIP electrode showed a Nernstian response to hydrogen phosphate anion; whereas, the non-imprinted polymer (NIP)-based electrode had no considerable sensitivity to the anion. The presence of both methacrylic acid and vinyl pyridine in the IIP structure, as well as optimization of the functional monomers-template proportion, was found to be important to observe the sensing capability of the IIP electrode. The nano-IIP electrode showed a dynamic linear range of 1 × 10 -5 -1 × 10 -1  mol L-1, Nernstian slope of 30.6 ± (0.5) mV decade -1 , response time of 25 seconds, and detection limit of 4.0 × 10 -6  mol L -1 . The utility of the electrodes was checked by potentiometric titration of hydrogen phosphate with La 3+ solution. Copyright © 2017 John Wiley & Sons, Ltd.

  13. The effect of amorphous silicon surface hydrogenation on morphology, wettability and its implication on the adsorption of proteins

    Energy Technology Data Exchange (ETDEWEB)

    Filali, Larbi, E-mail: larbifilali5@gmail.com [Laboratoire de Physique des Couches Minces et Matériaux pour l' Electronique, Université d' Oran 1, Ahmed Ben Bella, BP 1524, El M' naouar 31100 Oran (Algeria); Brahmi, Yamina; Sib, Jamal Dine [Laboratoire de Physique des Couches Minces et Matériaux pour l' Electronique, Université d' Oran 1, Ahmed Ben Bella, BP 1524, El M' naouar 31100 Oran (Algeria); Bouhekka, Ahmed [Laboratoire de Physique des Couches Minces et Matériaux pour l' Electronique, Université d' Oran 1, Ahmed Ben Bella, BP 1524, El M' naouar 31100 Oran (Algeria); Département de Physique, Université Hassiba Ben Bouali, 02000 Chlef (Algeria); Benlakehal, Djamel; Bouizem, Yahya; Kebab, Aissa; Chahed, Larbi [Laboratoire de Physique des Couches Minces et Matériaux pour l' Electronique, Université d' Oran 1, Ahmed Ben Bella, BP 1524, El M' naouar 31100 Oran (Algeria)

    2016-10-30

    Highlights: • Hydrogenation of the surfaces had the effect of reducing the roughness by way of shadow etching. • Roughness was the driving factor affecting the wettability of the hydrogenated surfaces. • Bovine Serum Albumin proteins favored the surfaces with highest hydrogen content. • Surface modification induced secondary structure change of adsorbed proteins. - Abstract: We study the effect of amorphous silicon (a-Si) surface hydrogenation on Bovine Serum Albumin (BSA) adsorption. A set of (a-Si) films was prepared by radio frequency magnetron sputtering (RFMS) and after deposition; they were treated in molecular hydrogen ambient at different pressures (1–3 Pa). Fourier transform infrared attenuated total reflection (FTIR-ATR) spectroscopy and spectroscopic ellipsometry (SE) were used to study the hydrogenation effect and BSA adsorption. Atomic force microscopy (AFM) was used to evaluate morphological changes caused by hydrogenation. The wettability of the films was measured using contact angle measurement, and in the case of the hydrogenated surfaces, it was found to be driven by surface roughness. FTIR-ATR spectroscopy and SE measurements show that proteins had the strongest affinity toward the surfaces with the highest hydrogen content and their secondary structure was affected by a significant decrease of the α-helix component (-27%) compared with the proteins adsorbed on the un-treated surface, which had a predominantly α-helix (45%) structure. The adsorbed protein layer was found to be densely packed with a large thickness (30.9 nm) on the hydrogen-rich surfaces. The most important result is that the surface hydrogen content was the dominant factor, compared to wettability and morphology, for protein adsorption.

  14. Calorimetric investigations of hydrogen bonding in binary mixtures containing pyridine and its methyl-substituted derivatives. II. The dilute solutions of methanol and 2-methyl-2-propanol

    International Nuclear Information System (INIS)

    Marczak, Wojciech; Heintz, Andreas; Bucek, Monika

    2004-01-01

    Enthalpies of solution of methanol and 2-methyl-2-propanol (tert-butanol) in pyridine and its methyl derivatives were investigated in the range of mole fractions of alcohol x≤0.02 at temperature 298.15 K by a titration calorimeter. Dissolution of methanol is an exothermic process, with heat effects very close to those for water reported in part I of this study. The negative enthalpy of solution increases in the following order: pyridine < 3-methylpyridine < 4-methylpyridine < 2-methylpyridine < 2,6-dimethylpyridine < 2,4,6-trimethylpyridine. Positive enthalpies of solution of 2-methyl-2-propanol increase as follows: 2-methylpyridine < 2,4,6-trimethylpyridine < 4-methylpyridine < 2,6-dimethylpyridine < 3-methylpyridine < pyridine. The propensity of pyridine derivatives to hydrogen bonding is enhanced by the ortho effect. Methyl groups are probably too small to prevent the nitrogen atom in the pyridine ring from hydrogen bonding. However, spacious hydrocarbon group in 2-methyl-2-propanol molecule makes the bonding difficult for 2,6-dimethylpyridine and 2,4,6-trimethylpyridine, thus the number of O-H···N bonds is smaller than that in the solutions of methanol or water. The two latter seem to be very close to each other

  15. Hydrogen-oxygen powered internal combustion engine

    Science.gov (United States)

    Cameron, H.; Morgan, N.

    1970-01-01

    Hydrogen at 300 psi and oxygen at 800 psi are injected sequentially into the combustion chamber to form hydrogen-rich mixture. This mode of injection eliminates difficulties of preignition, detonation, etc., encountered with carburated, spark-ignited, hydrogen-air mixtures. Ignition at startup is by means of a palladium catalyst.

  16. Solvent extraction of calcium and strontium into nitrobenzene by using synergistic mixture of hydrogen dicarbollylcobaltate and diphenyl-N-butylcarbamoylmethyl phosphine oxide

    International Nuclear Information System (INIS)

    Makrlik, E.

    2010-01-01

    Extraction of microamounts of calcium and strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H + B - ) in the presence of diphenyl-N-butylcarbamoylmethyl phosphine oxide (DPBCMPO, L) has been investigated. The equilibrium data have been explained assuming that the species HL + , HL 2 + , ML 2 2+ , ML 3 2+ and ML 4 2+ (M 2+ = Ca 2+ , Sr 2+ ) are extracted into the organic phase. The values of extraction and stability constants of the cationic complexes in nitrobenzene saturated with water have been determined. In the considered nitrobenzene medium, it was found that the stability of the SrL 2,org 2+ complex is somewhat higher than that of species CaL 2,org 2+ , while the stability constants of the remaining strontium complexes SrL 3,org 2+ and SrL 4,org 2+ are smaller than those of the corresponding complex species CaL n 2+ (n = 3, 4). (author)

  17. Synthesis and optical properties of BC{sub x}N{sub y} films deposited from N-triethylborazine and hydrogen mixture

    Energy Technology Data Exchange (ETDEWEB)

    Sulyaeva, Veronica S., E-mail: veronica@niic.nsc.ru [Department of Functional Materials Chemistry, Nikolaev Institute of Inorganic Chemistry, SB RAS, 630090 Novosibirsk (Russian Federation); Rumyantsev, Yurii M. [Department of Functional Materials Chemistry, Nikolaev Institute of Inorganic Chemistry, SB RAS, 630090 Novosibirsk (Russian Federation); Kesler, Valerii G. [Laboratory of Physical Principles for Integrated Microelectronics, Rzhanov Institute of Semiconductor Physics, SB RAS, 630090 Novosibirsk (Russian Federation); Kosinova, Marina L. [Department of Functional Materials Chemistry, Nikolaev Institute of Inorganic Chemistry, SB RAS, 630090 Novosibirsk (Russian Federation)

    2015-04-30

    BC{sub x}N{sub y} films were obtained by plasma enhanced chemical vapor deposition method using a single-source precursor N-triethylborazine and hydrogen as plasma activating gas. The effect of synthesis temperature on the chemical composition and properties of the BC{sub x}N{sub y} films was investigated. The BC{sub x}N{sub y} films were examined by scanning electron microscopy, Fourier transform infrared and Raman spectroscopy, X-ray energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and ellipsometry and spectrophotometry techniques. These experimental results indicated that the BC{sub x}N{sub y} films produced at low temperatures (T{sub dep} ≤ 673 K) are the polymer-like hydrogenated films with high transparency up to 93% in the visible part of the spectrum. BC{sub x}N{sub y} films produced at high temperatures (> 673 K) contain additional phase of disordered carbon which has dramatically reduce transparency. The band gap of the films varied from 0.6 to 4.5 eV, with variation in deposition temperature. - Highlights: • Thin BC{sub x}N{sub y} films have been obtained by plasma enhanced chemical vapor deposition. • N-triethylborazine was used as a precursor. • Low temperature BC{sub x}N{sub y} films were found to be high optical transparent layers (93%). • Optical band gap of the BC{sub x}N{sub y} layers varied from 0.6 to 4.5 eV.

  18. Study of volumetric properties (PVT) of mixtures made of light hydrocarbons (C1-C4), carbon dioxide and hydrogen sulfide - Experimental measurements through a vibrating tube densimeter and modelling; Etude des proprietes volumetriques (PVT) d'hydrocarbures legers (C1-C4), du dioxyde de carbone et de l'hydrogene sulfure. Mesures par densimetrie a tube vibrant et modelisation

    Energy Technology Data Exchange (ETDEWEB)

    Rivollet, F.

    2005-12-15

    Various pollutant contents (i.e. carbon dioxide, hydrogen sulphide or other sulphur products) are found in produced oils. These latter must undergo a number of transformations and purifications. The design and dimensioning of the corresponding units can well be optimized only if one has reliable and accurate data about phase equilibria and volumetric properties and of course reliable and accurate modeling. This work was devoted partly to measurements of volumetric properties on three binary mixtures (ethane - hydrogen sulphide, ethane - propane and carbon dioxide - hydrogen sulphide). These measurements were carried out using equipment, comprising a vibrating tube densimeter (Paar, model DMA 512 P), which was especially designed and built for this work. The binary mixtures were studied in the 253 to 363 K temperature range from at pressures up to either 20 or 40 MPa. Two calibration methods of the vibrating tube were used: the FPMC method (Forced Path Mechanical Calibration) described in the literature and an original method containing neural network, developed herein. The study undertaken about the modeling of volumetric properties made it possible to highlight the inadequacy of the traditional use of cubic equations of state to represent simultaneously volumetric properties and phase equilibria. Among the equations of state investigated, a close attention however was paid to cubic equations of state because of their very great use in the oil field. A new tool was found to adapt cubic equations of state to the simultaneous and satisfactory representation of volumetric properties and phase equilibria. It concerns the coupling of the cubic Redlich-Kwong-Soave equation of state with volume correction through a neural network. This new model was tested successfully, it makes it possible to benefit from the existing work of representation of phase equilibria (mixing rules and interaction coefficients) while improving calculation of the volumetric data.

  19. Containment loadings due to hydrogen burning in LWR core meltdown accidents

    International Nuclear Information System (INIS)

    Cybulskis, P.

    1981-01-01

    The potential pressure loadings due to hydrogen burning under conditions representative of meltdown accident conditions are examined for a variety of PWR and BWR containment designs. For the PWR, the large dry, ice condenser, as well as subatmospheric containments are considered. For the BWR, MARK I, II, and III pressure suppression containments are evaluated. The key factors considered are: free volume, design pressure, extend to hydrogen generation, and the flammability of the atmosphere under a range of accident conditions. The potential for and the possible implications of hydrogen detonation are also considered. The results of these analyses show that the accumulation and rapid burning of the quantities of hydrogen that would be generated during core meltdown accidents will lead to pressures above design levels in all of the containments considered. As would be expected, containments characterized by small volumes and/or low design pressures are the most vulnerable to damage due to hydrogen burning. Large volume, high pressure designs may also be threatened but offer significantly more potential for accomodating hydrogen burns. The attainment of detonable hydrogen mixtures is made easier by smaller containment volumes. Detonable mixtures are also possible in the larger volume containments, but imply the accumulation of hydrogen for long periods of time without prior ignition. Hydrogen detonations, if they occur, would probably challenge the integrity of any of the containments considered. (orig.)

  20. Zircaloy-oxidation and hydrogen-generation rates in degraded-core accident situations

    International Nuclear Information System (INIS)

    Chung, H.M.; Thomas, G.R.

    1983-02-01

    Oxidation of Zircaloy cladding is the primary source of hydrogen generated during a degraded-core accident. In this paper, reported Zircaloy oxidation rates, either measured at 1500 to 1850 0 C or extrapolated from the low-temperature data obtained at 0 C, are critically reviewed with respect to their applicability to a degraded-core accident situation in which the high-temperature fuel cladding is likely to be exposed to and oxidized in mixtures of hydrogen and depleted steam, rather than in an unlimited flux of pure steam. New results of Zircaloy oxidation measurements in various mixtures of hydrogen and steam are reported for >1500 0 C. The results show significantly smaller oxidation and, hence, hydrogen-generation rates in the mixture, compared with those obtained in pure steam. It is also shown that a significant fraction of hydrogen, generated as a result of Zircaloy oxidation, is dissolved in the cladding material itself, which prevents that portion of hydrogen from reaching the containment building space. Implications of these findings are discussed in relation to a more realistic method of quantifying the hydrogen source term for a degraded-core accident analysis

  1. Carbon and hydrogen isotope fractionation under continuous light: implications for paleoenvironmental interpretations of the High Arctic during Paleogene warming.

    Science.gov (United States)

    Yang, Hong; Pagani, Mark; Briggs, Derek E G; Equiza, M A; Jagels, Richard; Leng, Qin; Lepage, Ben A

    2009-06-01

    The effect of low intensity continuous light, e.g., in the High Arctic summer, on plant carbon and hydrogen isotope fractionations is unknown. We conducted greenhouse experiments to test the impact of light quantity and duration on both carbon and hydrogen isotope compositions of three deciduous conifers whose fossil counterparts were components of Paleogene Arctic floras: Metasequoia glyptostroboides, Taxodium distichum, and Larix laricina. We found that plant leaf bulk carbon isotopic values of the examined species were 1.75-4.63 per thousand more negative under continuous light (CL) than under diurnal light (DL). Hydrogen isotope values of leaf n-alkanes under continuous light conditions revealed a D-enriched hydrogen isotope composition of up to 40 per thousand higher than in diurnal light conditions. The isotope offsets between the two light regimes is explained by a higher ratio of intercellular to atmospheric CO(2) concentration (C (i)/C (a)) and more water loss for plants under continuous light conditions during a 24-h transpiration cycle. Apparent hydrogen isotope fractionations between source water and individual lipids (epsilon(lipid-water)) range from -62 per thousand (Metasequoia C(27) and C(29)) to -87 per thousand (Larix C(29)) in leaves under continuous light. We applied these hydrogen fractionation factors to hydrogen isotope compositions of in situ n-alkanes from well-preserved Paleogene deciduous conifer fossils from the Arctic region to estimate the deltaD value in ancient precipitation. Precipitation in the summer growing season yielded a deltaD of -186 per thousand for late Paleocene, -157 per thousand for early middle Eocene, and -182 per thousand for late middle Eocene. We propose that high-latitude summer precipitation in this region was supplemented by moisture derived from regionally recycled transpiration of the polar forests that grew during the Paleogene warming.

  2. Grouting mixture

    Energy Technology Data Exchange (ETDEWEB)

    Klyusov, A A; Bakshutov, V S; Kulyavtsev, V A

    1980-10-23

    A grouting mixture is proposed for low-temperature boreholes. The mixture contains cement, beta gypsum polyhydrate, and calcium chloride, so as to increase the water resistance and strength properties of expanding brick at conditions from 20 to -5/sup 0/ C, the components are in the following ratios: (by wt.-%): cement, 77.45-88.06; beta gypsum polyhydrate, 9.79-19.36; calcium chloride, 2.15-3.19. Grouting mortar for cold boreholes serves as the cement.

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

    Science.gov (United States)

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

    1993-01-01

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

  4. Contribution to the study of thermal diffusion in isotopic mixtures of hydrogen; Contribution a l'etude de la diffusion thermique dans les melanges isotopiques de l'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Lemarechal-Dupuis, A [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires

    1968-04-01

    Thermal diffusion constants of the mixtures H{sub 2}-HD and H{sub 2}-HT, where HD and HT were at trace concentrations, have been measured between 90 deg. K and 450 deg. K for H{sub 2}-HD and between 190 deg. K and 450 deg. K for H{sub 2}-HT, by using the elementary effect. Furthermore, the ratio of these constants has been measured by using a thermo-gravitational column of Clusius and Dickel, at temperatures of the hot wire between 455 deg. K and 1200 deg. K, the cold wall being at room temperature. Comparison with the predictions of existing theories shows that the Chapman-Enskog theory cannot account for the thermal diffusion of mixtures containing asymmetric molecules; the possible reasons for this disagreement are discussed. Our set of measurements, combined with the results of other authors, yields precise values at well defined conditions of temperature and concentration, useful for the determination of the coefficients of the semi-empirical expansion of Waldmann and Klemm. Furthermore some aspects of the column theory according to Furry and Jones have been tested. (author) [French] Les constantes de diffusion thermique des melanges H{sub 2}-HD et H{sub 2}-HT ou HD et HT figuraient, a l'etat de traces, ont ete mesurees a l'aide de l'effet elementaire entre 90 deg. K et 450 deg. K pour le melange H{sub 2}-HD,et entre 190 deg. K et 450 deg. K pour le melange H{sub 2}-HT. D'autre part, le rapport de ces constantes a ete mesure a l'aide d'une colonne de Clusius et Dickel pour des temperatures du fil chaud variant entre 455 deg. K et 1200 deg. K, la temperature de la paroi froide etant la temperature ambiante. La comparaison avec les predictions des theories existantes montre que la theorie de Chapman- Enskog ne peut rendre compte de la constante de diffusion thermique de melanges de molecules asymetriques; les raisons de ce desaccord sont discutees. L'ensemble de ces mesures, combine aux resultats d'autres auteurs, permet d'obtenir des valeurs precises dans des

  5. Chemical Kinetics of Hydrogen Atom Abstraction from Allylic Sites by 3O2; Implications for Combustion Modeling and Simulation.

    Science.gov (United States)

    Zhou, Chong-Wen; Simmie, John M; Somers, Kieran P; Goldsmith, C Franklin; Curran, Henry J

    2017-03-09

    Hydrogen atom abstraction from allylic C-H bonds by molecular oxygen plays a very important role in determining the reactivity of fuel molecules having allylic hydrogen atoms. Rate constants for hydrogen atom abstraction by molecular oxygen from molecules with allylic sites have been calculated. A series of molecules with primary, secondary, tertiary, and super secondary allylic hydrogen atoms of alkene, furan, and alkylbenzene families are taken into consideration. Those molecules include propene, 2-butene, isobutene, 2-methylfuran, and toluene containing the primary allylic hydrogen atom; 1-butene, 1-pentene, 2-ethylfuran, ethylbenzene, and n-propylbenzene containing the secondary allylic hydrogen atom; 3-methyl-1-butene, 2-isopropylfuran, and isopropylbenzene containing tertiary allylic hydrogen atom; and 1-4-pentadiene containing super allylic secondary hydrogen atoms. The M06-2X/6-311++G(d,p) level of theory was used to optimize the geometries of all of the reactants, transition states, products and also the hinder rotation treatments for lower frequency modes. The G4 level of theory was used to calculate the electronic single point energies for those species to determine the 0 K barriers to reaction. Conventional transition state theory with Eckart tunnelling corrections was used to calculate the rate constants. The comparison between our calculated rate constants with the available experimental results from the literature shows good agreement for the reactions of propene and isobutene with molecular oxygen. The rate constant for toluene with O 2 is about an order magnitude slower than that experimentally derived from a comprehensive model proposed by Oehlschlaeger and coauthors. The results clearly indicate the need for a more detailed investigation of the combustion kinetics of toluene oxidation and its key pyrolysis and oxidation intermediates. Despite this, our computed barriers and rate constants retain an important internal consistency. Rate constants

  6. Mixed quantum-classical molecular dynamics study of the hydroxyl stretch in methanol/carbon-tetrachloride mixtures II: excited state hydrogen bonding structure and dynamics, infrared emission spectrum, and excited state lifetime.

    Science.gov (United States)

    Kwac, Kijeong; Geva, Eitan

    2012-03-08

    We present a mixed quantum-classical molecular dynamics study of the hydrogen-bonding structure and dynamics of a vibrationally excited hydroxyl stretch in methanol/carbon-tetrachloride mixtures. The adiabatic Hamiltonian of the quantum-mechanical hydroxyl is diagonalized on-the-fly to obtain the ground and first-excited adiabatic energy levels and wave functions which depend parametrically on the instantaneous configuration of the classical degrees of freedom. The dynamics of the classical degrees of freedom are determined by Hellmann-Feynman forces obtained by taking the expectation value of the force with respect to the ground or excited vibrational wave functions. Polarizable force fields are used which were previously shown to reproduce the experimental infrared absorption spectrum rather well, for different isotopomers and over a wide composition range [Kwac, K.; Geva, E. J. Phys. Chem. B 2011, 115, 9184]. We show that the agreement of the absorption spectra with experiment can be further improved by accounting for the dependence of the dipole moment derivatives on the configuration of the classical degrees of freedom. We find that the propensity of a methanol molecule to form hydrogen bonds increases upon photoexcitation of its hydroxyl stretch, thereby leading to a sizable red-shift of the corresponding emission spectrum relative to the absorption spectrum. Treating the relaxation from the first excited to the ground state as a nonadiabatic process, and calculating its rate within the framework of Fermi's golden rule and the harmonic-Schofield quantum correction factor, we were able to predict a lifetime which is of the same order of magnitude as the experimental value. The experimental dependence of the lifetime on the transition frequency is also reproduced. Nonlinear mapping relations between the hydroxyl transition frequency and bond length in the excited state and the electric field along the hydroxyl bond axis are established. These mapping relations

  7. Oxidation resistant organic hydrogen getters

    Science.gov (United States)

    Shepodd, Timothy J [Livermore, CA; Buffleben, George M [Tracy, CA

    2008-09-09

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

  8. Life-cycle implications of hydrogen fuel cell electric vehicle technology for medium- and heavy-duty trucks

    Science.gov (United States)

    Lee, Dong-Yeon; Elgowainy, Amgad; Kotz, Andrew; Vijayagopal, Ram; Marcinkoski, Jason

    2018-07-01

    This study provides a comprehensive and up-to-date life-cycle comparison of hydrogen fuel cell electric trucks (FCETs) and their conventional diesel counterparts in terms of energy use and air emissions, based on the ensemble of well-established methods, high-fidelity vehicle dynamic simulations, and real-world vehicle test data. For the centralized steam methane reforming (SMR) pathway, hydrogen FCETs reduce life-cycle or well-to-wheel (WTW) petroleum energy use by more than 98% compared to their diesel counterparts. The reduction in WTW air emissions for gaseous hydrogen (G.H2) FCETs ranges from 20 to 45% for greenhouse gases, 37-65% for VOC, 49-77% for CO, 62-83% for NOx, 19-43% for PM10, and 27-44% for PM2.5, depending on vehicle weight classes and truck types. With the current U.S. average electricity generation mix, FCETs tend to create more WTW SOx emissions than their diesel counterparts, mainly because of the upstream emissions related to electricity use for hydrogen compression/liquefaction. Compared to G.H2, liquid hydrogen (L.H2) FCETs generally provide smaller WTW emissions reductions. For both G.H2 and L.H2 pathways for FCETs, because of electricity consumption for compression and liquefaction, spatio-temporal variations of electricity generation can affect the WTW results. FCETs retain the WTW emission reduction benefits, even when considering aggressive diesel engine efficiency improvement.

  9. A comparison of hydrogen, methanol and gasoline as fuels for fuel cell vehicles: implications for vehicle design and infrastructure development

    Science.gov (United States)

    Ogden, Joan M.; Steinbugler, Margaret M.; Kreutz, Thomas G.

    All fuel cells currently being developed for near term use in electric vehicles require hydrogen as a fuel. Hydrogen can be stored directly or produced onboard the vehicle by reforming methanol, or hydrocarbon fuels derived from crude oil (e.g., gasoline, diesel, or middle distillates). The vehicle design is simpler with direct hydrogen storage, but requires developing a more complex refueling infrastructure. In this paper, we present modeling results comparing three leading options for fuel storage onboard fuel cell vehicles: (a) compressed gas hydrogen storage, (b) onboard steam reforming of methanol, (c) onboard partial oxidation (POX) of hydrocarbon fuels derived from crude oil. We have developed a fuel cell vehicle model, including detailed models of onboard fuel processors. This allows us to compare the vehicle performance, fuel economy, weight, and cost for various vehicle parameters, fuel storage choices and driving cycles. The infrastructure requirements are also compared for gaseous hydrogen, methanol and gasoline, including the added costs of fuel production, storage, distribution and refueling stations. The delivered fuel cost, total lifecycle cost of transportation, and capital cost of infrastructure development are estimated for each alternative. Considering both vehicle and infrastructure issues, possible fuel strategies leading to the commercialization of fuel cell vehicles are discussed.

  10. Radiolytic decomposition of water-ethanol mixtures

    International Nuclear Information System (INIS)

    Baquey, Charles

    1968-07-01

    This research thesis addresses the study of the behaviour of binary mixtures submitted to ionizing radiations, and notably aims, by studying the case of water-ethanol mixtures, at verifying solutions proposed by previously published works on the origin of hydrogen atoms and of molecular hydrogen, on the intervention of excited atoms, and on the origin of products appearing under radiolysis. The experimental part of this work consists in the dosing of products formed in water-ethanol mixtures irradiated in presence or absence of nitrate, hydrogen, hydrocarbon, acetaldehyde, 2-3 butanediol and nitrite. Results are discussed and interpreted in terms of acetaldehyde efficiency, 2-3 butanediol efficiencies, and hydrocarbon efficiencies in pure ethanol, and in water-ethanol mixtures. The influence of the presence of nitrate ions in mixtures is also discussed

  11. Determination of hydrogen content of Jatropha biodiesel oil using neutron reflection technique

    International Nuclear Information System (INIS)

    Okunade, I. O.; Jonah, S. A.; Omede, M.

    2014-01-01

    Biofuel is an environmental-friendly alternative to fossil fuel and holds immense potential for the future energy needs of the country. Non-edible jatropha biodiesel oil has been identified as one of the suitable bio-fuel options. In this work, experimental measurements were performed to determine the total hydrogen content of jatropha oil and jatropha-synthetic diesel oil mixture. The work was carried out using a neutron reflection facility at the Centre for Energy Research and Training, Ahmadu Bello University, Zaria. Jatropha oil and jatropha-synthetic diesel mixture were subjected to experimental measurements for the purpose of determining bulk hydrogen content using neutron reflection facility that had been previously calibrated using various hydrocarbon materials of known hydrogen content. The hydrogen content of the sample were subsequently determined using their measured neutron reflection coefficient values and calibration data. In general, results obtained indicate high hydrogen content range of 10.68-12.16wt% for jatropha oil and the various jatropha-synthetic diesel mixtures. The implication of this is that jatropha oil or jatrophal-synthetic diesel mixture can be used as alternative fuel to mitigate high carbon monoxide emission.

  12. Photooxidation of farnesene mixtures in the presence of NOx: Analysis of reaction products and their implication to ambient PM2.5

    Data.gov (United States)

    U.S. Environmental Protection Agency — Chemical analysis of SOA produced from the irradiation of a mixture of α/β-farnesene/NOx was conducted in a 14.5 cubic meter smog chamber. SOA collected on...

  13. Public attitudes towards and demand for hydrogen and fuel cell vehicles. A review of the evidence and methodological implications

    International Nuclear Information System (INIS)

    Yetano Roche, Maria; Mourato, Susana; Fischedick, Manfred; Pietzner, Katja; Viebahn, Peter

    2010-01-01

    It is now widely recognized that effective communication and demand-side policies for alternative energy require sound knowledge of preferences and determinants of demand of the public and consumers. To date, public attitudes towards new transport technologies have been studied under very different conceptual frameworks. This paper gives an overview of the various conceptual frameworks and methodologies used, where four main approaches can be distinguished: general attitudinal surveys, risk perception studies, non-market economic valuation studies, and other approaches such as those based on semiotic theory. We then review the findings of the recent literature on acceptance, attitudes and preferences for hydrogen and fuel cell end-use technologies, focusing on vehicles. These studies are then contrasted with related research into alternative fuel vehicles. The paper finally discusses the main trends in research and avenues for further work in this field. We recommend, among other things, the use of approaches that build knowledge and familiarity with the technology prior to the exploration of attitudes, and the set up of studies that take a whole-systems perspective of hydrogen technologies and that look at hydrogen in the context of other competing clean technologies. (author)

  14. Public attitudes towards and demand for hydrogen and fuel cell vehicles. A review of the evidence and methodological implications

    Energy Technology Data Exchange (ETDEWEB)

    Yetano Roche, Maria [Wuppertal Institute for Climate, Energy and Environment, PO BOX 100480, 42004 Wuppertal (Germany); Department of Geography and Environment, London School of Economics and Political Science (United Kingdom); Mourato, Susana [Department of Geography and Environment, London School of Economics and Political Science (United Kingdom); Fischedick, Manfred; Pietzner, Katja; Viebahn, Peter [Wuppertal Institute for Climate, Energy and Environment, PO BOX 100480, 42004 Wuppertal (Germany)

    2010-10-15

    It is now widely recognized that effective communication and demand-side policies for alternative energy require sound knowledge of preferences and determinants of demand of the public and consumers. To date, public attitudes towards new transport technologies have been studied under very different conceptual frameworks. This paper gives an overview of the various conceptual frameworks and methodologies used, where four main approaches can be distinguished: general attitudinal surveys, risk perception studies, non-market economic valuation studies, and other approaches such as those based on semiotic theory. We then review the findings of the recent literature on acceptance, attitudes and preferences for hydrogen and fuel cell end-use technologies, focusing on vehicles. These studies are then contrasted with related research into alternative fuel vehicles. The paper finally discusses the main trends in research and avenues for further work in this field. We recommend, among other things, the use of approaches that build knowledge and familiarity with the technology prior to the exploration of attitudes, and the set up of studies that take a whole-systems perspective of hydrogen technologies and that look at hydrogen in the context of other competing clean technologies. (author)

  15. Public attitudes towards and demand for hydrogen and fuel cell vehicles: A review of the evidence and methodological implications

    Energy Technology Data Exchange (ETDEWEB)

    Yetano Roche, Maria, E-mail: maria.yetano@wupperinst.or [Wuppertal Institute for Climate, Energy and Environment, PO BOX 100480, 42004 Wuppertal (Germany) and Department of Geography and Environment; London School of Economics and Political Science, Houghton Street, London WC2A 2AE (United Kingdom); Mourato, Susana [Department of Geography and Environment, London School of Economics and Political Science, Houghton Street, London WC2A 2AE (United Kingdom); Fischedick, Manfred; Pietzner, Katja; Viebahn, Peter [Wuppertal Institute for Climate, Energy and Environment, PO BOX 100480, 42004 Wuppertal (Germany)

    2010-10-15

    It is now widely recognized that effective communication and demand-side policies for alternative energy require sound knowledge of preferences and determinants of demand of the public and consumers. To date, public attitudes towards new transport technologies have been studied under very different conceptual frameworks. This paper gives an overview of the various conceptual frameworks and methodologies used, where four main approaches can be distinguished: general attitudinal surveys, risk perception studies, non-market economic valuation studies, and other approaches such as those based on semiotic theory. We then review the findings of the recent literature on acceptance, attitudes and preferences for hydrogen and fuel cell end-use technologies, focusing on vehicles. These studies are then contrasted with related research into alternative fuel vehicles. The paper finally discusses the main trends in research and avenues for further work in this field. We recommend, among other things, the use of approaches that build knowledge and familiarity with the technology prior to the exploration of attitudes, and the set up of studies that take a whole-systems perspective of hydrogen technologies and that look at hydrogen in the context of other competing clean technologies.

  16. Process for exchanging hydrogen isotopes between gaseous hydrogen and water

    International Nuclear Information System (INIS)

    Hindin, S.G.; Roberts, G.W.

    1977-01-01

    A process is described for exchanging isotopes (particularly tritium) between water and gaseous hydrogen. Isotope depleted gaseous hydrogen and water containing a hydrogen isotope are introduced into the vapour phase in a first reaction area. The steam and gaseous hydrogen are brought into contact with a supported metal catalyst in this area in a parallel flow at a temperature range of around 225 and 300 0 C. An effluent flow comprising a mixture of isotope enriched gaseous hydrogen and depleted steam is evacuated from this area and the steam condensed into liquid water [fr

  17. Twenty-nine years of development in planted cherrybark oak-sweetgum mixtures: implications for future mixed-species hardwood plantations

    Science.gov (United States)

    Brian Roy Lockhart; Andrew W. Ezell; John D. Hodges; Wayne K. Clatterbuck

    2012-01-01

    Results from a long-term planted mixture of cherrybark oak (Quercus pagoda Raf.) and sweetgum (Liquidambar styraciflua L.) showed sweetgum taller in height and larger in diameter than cherrybark oak early in plantation development. By age 17, cherrybark oak was similar in height and diameter with sweetgum and by age 21 was taller...

  18. Thermal infrared spectral analysis of compacted fine-grained mineral mixtures: implications for spectral interpretation of lithified sedimentary materials on Mars

    Science.gov (United States)

    Pan, C.; Rogers, D.

    2012-12-01

    Characterizing the thermal infrared (TIR) spectral mixing behavior of compacted fine-grained mineral assemblages is necessary for facilitating quantitative mineralogy of sedimentary surfaces from spectral measurements. Previous researchers have demonstrated that TIR spectra from igneous and metamorphic rocks as well as coarse-grained (>63 micron) sand mixtures combine in proportion to their volume abundance. However, the spectral mixing behavior of compacted, fine-grained mineral mixtures that would be characteristic of sedimentary depositional environments has received little attention. Here we characterize the spectral properties of pressed pellet samples of pestle and centrifuged to obtain less than 10 micron size. Pure phases and mixtures of two, three and four components were made in varying proportions by volume. All of the samples were pressed into pellets at 15000PSI to minimize volume scattering. Thermal infrared spectra of pellets were measured in the Vibrational Spectroscopy Laboratory at Stony Brook University with a Thermo Fisher Nicolet 6700 Fourier transform infrared Michelson interferometer from ~225 to 2000 cm-1. Our preliminary results indicate that some pelletized samples have contributions from volume scattering, which leads to non-linear spectral combinations. It is not clear if the transparency features (which arise from multiple surface reflections of incident photons) are due to minor clinging fines on an otherwise specular pellet surface or to partially transmitted energy through optically thin grains in the compacted mixture. Inclusion of loose powder (analysis of TES and Mini-TES data of lithified sedimentary deposits.

  19. Experimental reduction of simulated lunar glass by carbon and hydrogen and implications for lunar base oxygen production

    International Nuclear Information System (INIS)

    Mckay, D.S.; Morris, R.V.; Jurewicz, A.J.

    1991-01-01

    The most abundant element in lunar rocks and soils is oxygen which makes up approximately 45 percent by weight of the typical lunar samples returned during the Apollo missions. This oxygen is not present as a gas but is tightly bound to other elements in mineral or glass. When people return to the Moon to explore and live, the extraction of this oxygen at a lunar outpost may be a major goal during the early years of operation. Among the most studied processes for oxygen extraction is the reduction of ilmenite by hydrogen gas to form metallic iron, titanium oxide, and oxygen. A related process is proposed which overcomes some of the disadvantages of ilmenite reduction. It is proposed that oxygen can be extracted by direct reduction of native lunar pyroclactic glass using either carbon, carbon monoxide, or hydrogen. In order to evaluate the feasibility of this proposed process a series of experiments on synthetic lunar glass are presented. The results and a discussion of the experiments are presented

  20. Hydrogen energy

    International Nuclear Information System (INIS)

    2005-03-01

    This book consists of seven chapters, which deals with hydrogen energy with discover and using of hydrogen, Korean plan for hydrogen economy and background, manufacturing technique on hydrogen like classification and hydrogen manufacture by water splitting, hydrogen storage technique with need and method, hydrogen using technique like fuel cell, hydrogen engine, international trend on involving hydrogen economy, technical current for infrastructure such as hydrogen station and price, regulation, standard, prospect and education for hydrogen safety and system. It has an appendix on related organization with hydrogen and fuel cell.

  1. Biological hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Benemann, J.R. [Univ. of California, Berkeley, CA (United States)

    1995-11-01

    Biological hydrogen production can be accomplished by either thermochemical (gasification) conversion of woody biomass and agricultural residues or by microbiological processes that yield hydrogen gas from organic wastes or water. Biomass gasification is a well established technology; however, the synthesis gas produced, a mixture of CO and H{sub 2}, requires a shift reaction to convert the CO to H{sub 2}. Microbiological processes can carry out this reaction more efficiently than conventional catalysts, and may be more appropriate for the relatively small-scale of biomass gasification processes. Development of a microbial shift reaction may be a near-term practical application of microbial hydrogen production.

  2. AB INITIO EQUATIONS OF STATE FOR HYDROGEN (H-REOS.3) AND HELIUM (He-REOS.3) AND THEIR IMPLICATIONS FOR THE INTERIOR OF BROWN DWARFS

    International Nuclear Information System (INIS)

    Becker, Andreas; Lorenzen, Winfried; Schöttler, Manuel; Redmer, Ronald; Fortney, Jonathan J.; Nettelmann, Nadine

    2014-01-01

    We present new equations of state (EOSs) for hydrogen and helium covering a wide range of temperatures from 60 K to 10 7 K and densities from 10 –10 g cm –3 to 10 3 g cm –3 . They include an extended set of ab initio EOS data for the strongly correlated quantum regime with an accurate connection to data derived from other approaches for the neighboring regions. We compare linear mixing isotherms based on our EOS tables with available real mixture data. A first important astrophysical application of this new EOS data is the calculation of interior models for Jupiter and comparison with recent results. Second, mass-radius relations are calculated for Brown Dwarfs (BDs) which we compare with predictions derived from the widely used EOS of Saumon, Chabrier, and van Horn. Furthermore, we calculate interior models for typical BDs with different masses, namely, Corot-3b, Gliese-229b, and Corot-15b, and the giant planet KOI-889b. The predictions for the central pressures and densities differ by up to 10% dependent on the EOS used. Our EOS tables are made available in the supplemental material of this paper

  3. Paleoclimatic implications of the hydrogen isotopic composition of terrigenous n-alkanes from Lake Yamzho, southern Tibetan Plateau

    International Nuclear Information System (INIS)

    Xia Zhonghuan; Xu Baiqing; Wu Guangjian; Zhu Liping; Muegler Ines; Gleixner, Gerd; Sachse, Dirk

    2009-01-01

    The hydrogen isotopic composition (δD) of leaf water used for biosynthesis of n-alkanes can be modified by climate. Therefore, the δD can be considered as potential paleolimatic proxy to explore. We compared measured δD values of alkanes (n-C 25 to n-C 31 ) extracted from a short sediment profile spanning the past 50 years with a 7-year resolution from Lake Yamzho, southern Tibetan Plateau. Climatic control was reconstructed using meteorological records of the nearby Langkazi and Lhasa weather stations. We found that the δD values of the n-alkanes correlated with the mean annular air temperature and significantly correlated with the mean growing season air temperature. On the other hand, the δD values show poor correlations with both rainfall amount and relative humidity. These results indicate that stable isotope composition of n-alkanes could be an excellent proxy for paleotemperature reconstruction. (author)

  4. The Diurnal Variation of Hydrogen, Nitrogen, and Chlorine Radicals: Implications for the Heterogeneous Production of HNO2

    Science.gov (United States)

    Salawitch, R. J.; Wofsy, S. C.; Wennberg, P. O.; Cohen, R. C.; Anderson, J. G.; Fahey, D. W.; Gao, R. S.; Keim, E. R.; Woodbridge, E. L.; Stimpfle, R. M.; hide

    1994-01-01

    In situ measurements of hydrogen, nitrogen, and chlorine radicals obtained through sunrise and sunset in the lower stratosphere during SPADE are compared to results from a photochemical model constrained by observed concentrations of radical precursors and environmental conditions. Models allowing for heterogeneous hydrolysis of N205 on sulfate aerosols agree with measured concentrations of NO, NO2, and ClO throughout the day, but fail to account for high concentrations of OH and H02 observed near sunrise and sunset. The morning burst of [OH] and [HO2] coincides with the rise of [NO] from photolysis of N02, suggesting a new source of HO, that photolyzes in the near UV (350 to 400 nm) spectral region. A model that allows for the heterogeneous production of HN02 results in an excellent simulation of the diurnal variations of [OH] and [HO2].

  5. Calculation of electron transport in Ar/N2 and He/Kr gas mixtures emdash implications for validity of the Blanc close-quote s law method

    International Nuclear Information System (INIS)

    Wang, Y.; Van Brunt, R.J.

    1997-01-01

    The electron drift velocities and corresponding mean energies have been calculated numerically using an approximate two-term solution of the Boltzmann transport equation for Ar/N 2 gas mixtures at electric field-to-gas density ratios (E/N) below 2.0x10 -20 Vm 2 (20 Td) and for He/Kr mixtures at E/N below 5.0x10 -21 Vm 2 (5.0 Td). The results are compared with predictions obtained from a method proposed by Chiflikian based on an open-quotes analog of Blanc close-quote s lawclose quotes [Phys. Plasmas 2, 3902 (1995)]. Large differences are found between the results derived from the Blanc close-quote s law method and those found here from solutions of the transport equation that indicate serious errors and limitations associated with use of the Blanc close-quote s law method to compute drift velocities in gas mixtures. copyright 1997 American Institute of Physics

  6. Hydrogen as automotive fuel

    International Nuclear Information System (INIS)

    Ambrosini, G.; Ciancia, A.; Pede, G.; Brighigna, M.

    1993-01-01

    Hydrogen fueled vehicles may just be the answer to the air pollution problem in highly polluted urban environments where the innovative vehicle's air pollution abatement characteristics would justify its high operating costs as compared with those of conventional automotive alternatives. This paper examines the feasibility of hydrogen as an automotive fuel by analyzing the following aspects: the chemical-physical properties of hydrogen in relation to its use in internal combustion engines; the modifications necessary to adapt internal combustion engines to hydrogen use; hydrogen fuel injection systems; current production technologies and commercialization status of hydrogen automotive fuels; energy efficiency ratings; environmental impacts; in-vehicle storage systems - involving the use of hydrides, high pressure systems and liquid hydrogen storage systems; performance in terms of pay-load ratio; autonomous operation; and operating costs. With reference to recent trial results being obtained in the USA, an assessment is also made of the feasibility of the use of methane-hydrogen mixtures as automotive fuels. The paper concludes with a review of progress being made by ENEA (the Italian Agency for New Technology, Energy and the Environment) in the development of fuel storage and electronic fuel injection systems for hydrogen powered vehicles

  7. Understanding oscillatory phenomena in molecular hydrogen generation via sodium borohydride hydrolysis.

    Science.gov (United States)

    Budroni, M A; Biosa, E; Garroni, S; Mulas, G R C; Marchettini, N; Culeddu, N; Rustici, M

    2013-11-14

    The hydrolysis of borohydride salts represents one of the most promising processes for the generation of high purity molecular hydrogen under mild conditions. In this work we show that the sodium borohydride hydrolysis exhibits a fingerprinting periodic oscillatory transient in the hydrogen flow over a wide range of experimental conditions. We disproved the possibility that flow oscillations are driven by supersaturation phenomena of gaseous bubbles in the reactive mixture or by a nonlinear thermal feedback according to a thermokinetic model. Our experimental results indicate that the NaBH4 hydrolysis is a spontaneous inorganic oscillator, in which the hydrogen flow oscillations are coupled to an "oscillophor" in the reactive solution. The discovery of this original oscillator paves the way for a new class of chemical oscillators, with fundamental implications not only for testing the general theory on oscillations, but also with a view to chemical control of borohydride systems used as a source of hydrogen based green fuel.

  8. Comparative transcriptomic profiling of hydrogen peroxide signaling networks in zebrafish and human keratinocytes: Implications toward conservation, migration and wound healing.

    Science.gov (United States)

    Lisse, Thomas S; King, Benjamin L; Rieger, Sandra

    2016-02-05

    Skin wounds need to be repaired rapidly after injury to restore proper skin barrier function. Hydrogen peroxide (H2O2) is a conserved signaling factor that has been shown to promote a variety of skin wound repair processes, including immune cell migration, angiogenesis and sensory axon repair. Despite growing research on H2O2 functions in wound repair, the downstream signaling pathways activated by this reactive oxygen species in the context of injury remain largely unknown. The goal of this study was to provide a comprehensive analysis of gene expression changes in the epidermis upon exposure to H2O2 concentrations known to promote wound repair. Comparative transcriptome analysis using RNA-seq data from larval zebrafish and previously reported microarray data from a human epidermal keratinocyte line shows that H2O2 activates conserved cell migration, adhesion, cytoprotective and anti-apoptotic programs in both zebrafish and human keratinocytes. Further assessment of expression characteristics and signaling pathways revealed the activation of three major H2O2-dependent pathways, EGF, FOXO1, and IKKα. This study expands on our current understanding of the clinical potential of low-level H2O2 for the promotion of epidermal wound repair and provides potential candidates in the treatment of wound healing deficits.

  9. The Viscosity of Organic Liquid Mixtures

    Science.gov (United States)

    Len, C. W.; Trusler, J. P. M.; Vesovic, V.; Wakeham, W. A.

    2006-01-01

    The paper reports measurements of the viscosity and density of two heavy hydrocarbon mixtures, Dutrex and Arab Light Flashed Distillate (ALFD), and of their mixtures with hydrogen. The measurements have been carried out with a vibrating-wire device over a range of temperatures from 399 to 547 K and at pressures up to 20 MPa. Measurements have also been carried out on systems in which hydrogen at different concentrations has been dissolved in the liquids. The measurements have an estimated uncertainty of ±5% for viscosity and ±2% for density and represent the first results on these prototypical heavy hydrocarbons. The results reveal that the addition of hydrogen reduces both the density and viscosity of the original hydrocarbon mixture at a particular temperature and pressure.

  10. Capillary condensation and adsorption of binary mixtures.

    Science.gov (United States)

    Weinberger, B; Darkrim-Lamari, F; Levesque, D

    2006-06-21

    The adsorption of equimolar binary mixtures of hydrogen-carbon dioxide, hydrogen-methane, and methane-carbon dioxide in porous material models is determined by grand canonical Monte Carlo simulations. The material models have an adsorbent surface similar to that of nanofibers with a herringbone structure. Our main result, which is relevant for hydrogen purification and carbon dioxide capture, is that the adsorption selectivities calculated for the mixtures can differ significantly from those deduced from simulations of the adsorption of pure gases, in particular, when one of the adsorbed gases presents a capillary condensation induced by confinement within the pore network. A comparison of our data is also made with theoretical models used in the literature for predicting the properties of the mixture adsorption.

  11. THE HYDROGEN EPOCH OF REIONIZATION ARRAY DISH. II. CHARACTERIZATION OF SPECTRAL STRUCTURE WITH ELECTROMAGNETIC SIMULATIONS AND ITS SCIENCE IMPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Ewall-Wice, Aaron; Hewitt, Jacqueline; Neben, Abraham R. [MIT Kavli Institute for Cosmological Physics, Cambridge, MA, 02139 (United States); Bradley, Richard; Dickenson, Roger; Doolittle, Phillip; Egan, Dennis; Hedrick, Mike; Klima, Patricia [National Radio Astronomy Observatory, Charlottesville, VA (United States); Deboer, David; Parsons, Aaron; Ali, Zaki S.; Cheng, Carina; Patra, Nipanjana; Dillon, Joshua S. [Department of Astronomy, University of California, Berkeley, CA (United States); Aguirre, James [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA (United States); Bowman, Judd; Thyagarajan, Nithyanandan [Arizona State University, School of Earth and Space Exploration, Tempe, AZ 85287 (United States); Venter, Mariet [Department of Electrical and Electronic Engineering, Stellenbosch University, Stellenbosch, SA (South Africa); Acedo, Eloy de Lera [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom); and others

    2016-11-10

    We use time-domain electromagnetic simulations to determine the spectral characteristics of the Hydrogen Epoch of Reionization Arrays (HERA) antenna. These simulations are part of a multi-faceted campaign to determine the effectiveness of the dish’s design for obtaining a detection of redshifted 21 cm emission from the epoch of reionization. Our simulations show the existence of reflections between HERA’s suspended feed and its parabolic dish reflector that fall below -40 dB at 150 ns and, for reasonable impedance matches, have a negligible impact on HERA’s ability to constrain EoR parameters. It follows that despite the reflections they introduce, dishes are effective for increasing the sensitivity of EoR experiments at a relatively low cost. We find that electromagnetic resonances in the HERA feed’s cylindrical skirt, which is intended to reduce cross coupling and beam ellipticity, introduces significant power at large delays (-40 dB at 200 ns), which can lead to some loss of measurable Fourier modes and a modest reduction in sensitivity. Even in the presence of this structure, we find that the spectral response of the antenna is sufficiently smooth for delay filtering to contain foreground emission at line-of-sight wave numbers below k {sub ∥} ≲ 0.2 h Mpc{sup -1}, in the region where the current PAPER experiment operates. Incorporating these results into a Fisher Matrix analysis, we find that the spectral structure observed in our simulations has only a small effect on the tight constraints HERA can achieve on parameters associated with the astrophysics of reionization.

  12. THE HYDROGEN EPOCH OF REIONIZATION ARRAY DISH. II. CHARACTERIZATION OF SPECTRAL STRUCTURE WITH ELECTROMAGNETIC SIMULATIONS AND ITS SCIENCE IMPLICATIONS

    International Nuclear Information System (INIS)

    Ewall-Wice, Aaron; Hewitt, Jacqueline; Neben, Abraham R.; Bradley, Richard; Dickenson, Roger; Doolittle, Phillip; Egan, Dennis; Hedrick, Mike; Klima, Patricia; Deboer, David; Parsons, Aaron; Ali, Zaki S.; Cheng, Carina; Patra, Nipanjana; Dillon, Joshua S.; Aguirre, James; Bowman, Judd; Thyagarajan, Nithyanandan; Venter, Mariet; Acedo, Eloy de Lera

    2016-01-01

    We use time-domain electromagnetic simulations to determine the spectral characteristics of the Hydrogen Epoch of Reionization Arrays (HERA) antenna. These simulations are part of a multi-faceted campaign to determine the effectiveness of the dish’s design for obtaining a detection of redshifted 21 cm emission from the epoch of reionization. Our simulations show the existence of reflections between HERA’s suspended feed and its parabolic dish reflector that fall below -40 dB at 150 ns and, for reasonable impedance matches, have a negligible impact on HERA’s ability to constrain EoR parameters. It follows that despite the reflections they introduce, dishes are effective for increasing the sensitivity of EoR experiments at a relatively low cost. We find that electromagnetic resonances in the HERA feed’s cylindrical skirt, which is intended to reduce cross coupling and beam ellipticity, introduces significant power at large delays (-40 dB at 200 ns), which can lead to some loss of measurable Fourier modes and a modest reduction in sensitivity. Even in the presence of this structure, we find that the spectral response of the antenna is sufficiently smooth for delay filtering to contain foreground emission at line-of-sight wave numbers below k ∥ ≲ 0.2 h Mpc -1 , in the region where the current PAPER experiment operates. Incorporating these results into a Fisher Matrix analysis, we find that the spectral structure observed in our simulations has only a small effect on the tight constraints HERA can achieve on parameters associated with the astrophysics of reionization.

  13. Simulating the Compton-Getting effect for hydrogen flux measurements: Implications for IBEX-Hi and -Lo observations

    International Nuclear Information System (INIS)

    Zirnstein, E. J.; Heerikhuisen, J.; McComas, D. J.; Schwadron, N. A.

    2013-01-01

    The Interstellar Boundary EXplorer (IBEX), launched in 2008 October, has improved our understanding of the solar wind-local interstellar medium interaction through its detection of neutral atoms, particularly that of hydrogen (H). IBEX is able to create full maps of the sky in six-month intervals as the Earth orbits the Sun, detecting H with energies between ∼0.01 and 6 keV. Due to the relative motion of IBEX to the solar inertial frame, measurements made in the spacecraft frame introduce a Compton-Getting (CG) effect, complicating measurements at the lowest energies. In this paper we provide results from a numerical simulation that calculates fluxes of H atoms at 1 AU in the inertial and spacecraft frames (both ram and anti-ram), at energies relevant to IBEX-Hi and -Lo. We show theory behind the numerical simulations, applying a simple frame transformation to derived flux equations that provides a straightforward way to simulate fluxes in the spacecraft frame. We then show results of H energetic neutral atom fluxes simulated at IBEX-Hi energy passbands 2-6 in all frames, comparing with IBEX-Hi data along selected directions, and also show results simulated at energies relevant to IBEX-Lo. Although simulations at IBEX-Hi energies agree reasonably well with the CG correction method used for IBEX-Hi data, we demonstrate the importance of properly modeling low energy H fluxes due to inherent complexities involved with measurements made in moving frames, as well as dynamic radiation pressure effects close to the Sun.

  14. Hydrogen Peroxide Cycling in High-Temperature Acidic Geothermal Springs and Potential Implications for Oxidative Stress Response

    Directory of Open Access Journals (Sweden)

    Margaux M. Meslé

    2017-05-01

    Full Text Available Hydrogen peroxide (H2O2, superoxide (O2•-, and hydroxyl radicals (OH• are produced in natural waters via ultraviolet (UV light-induced reactions between dissolved oxygen (O2 and organic carbon, and further reaction of H2O2 and Fe(II (i.e., Fenton chemistry. The temporal and spatial dynamics of H2O2 and other dissolved compounds [Fe(II, Fe(III, H2S, O2] were measured during a diel cycle (dark/light in surface waters of three acidic geothermal springs (Beowulf Spring, One Hundred Springs Plain, and Echinus Geyser Spring; pH = 3–3.5, T = 68–80°C in Norris Geyser Basin, Yellowstone National Park. In situ analyses showed that H2O2 concentrations were lowest (ca. 1 μM in geothermal source waters containing high dissolved sulfide (and where oxygen was below detection and increased by 2-fold (ca. 2–3 μM in oxygenated waters corresponding to Fe(III-oxide mat formation down the water channel. Small increases in dissolved oxygen and H2O2 were observed during peak photon flux, but not consistently across all springs sampled. Iron-oxide microbial mats were sampled for molecular analysis of ROS gene expression in two primary autotrophs of acidic Fe(III-oxide mat ecosystems: Metallosphaera yellowstonensis (Archaea and Hydrogenobaculum sp. (Bacteria. Expression (RT-qPCR assays of specific stress-response genes (e.g., superoxide dismutase, peroxidases of the primary autotrophs were used to evaluate possible changes in transcription across temporal, spatial, and/or seasonal samples. Data presented here documented the presence of H2O2 and general correlation with dissolved oxygen. Moreover, two dominant microbial populations expressed ROS response genes throughout the day, but showed less expression of key genes during peak sunlight. Oxidative stress response genes (especially external peroxidases were highly-expressed in microorganisms within Fe(III-oxide mat communities, suggesting a significant role for these proteins during survival and growth in

  15. Material and energy balances of an integrated biological hydrogen production and purification system and their implications for its potential to reduce greenhouse gas emissions.

    Science.gov (United States)

    Fukushima, Yasuhiro; Huang, Yu-Jung; Chen, Jhen-Wei; Lin, Hung-Chun; Whang, Liang-Ming; Chu, Hsin; Lo, Young-Chong; Chang, Jo-Shu

    2011-09-01

    The materials and energy in an integrated biological hydrogen production and purification system involving hydrolysis, dark fermentation, photo fermentation, CO2 fixation and anaerobic digestion are balanced by integrating the results from multiple experiments, simulations and the literature. The findings are two fold. First, using 1000 kg rice straw as a substrate, 19.8 kg H2 and 138.0 kg CH4 are obtained. The net energy balance (NEB) and net energy ratio (NER) are -738.4 kWh and 77.8%, respectively, both of which imply an unfavorable energy production system. Opportunities to improve the performance particularly lie in the photo fermentation process. Second, greenhouse gas emissions are evaluated for various options. The results were comparable with the emission inventory of electricity generated from fossil fuels. NEB and NER under a zero-carbon-emission constraint were discussed in detail to clarify completely the implications of the energy and material balances on greenhouse gas emissions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Nitrocarburizing in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2011-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  17. Nitrocarburising in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammoniapropene- hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  18. Hydrogen isotope effect through Pd in hydrogen transport pipe

    International Nuclear Information System (INIS)

    Tamaki, Masayoshi

    1992-01-01

    This investigation concerns hydrogen system with hydrogen transport pipes for transportation, purification, isotope separation and storage of hydrogen and its isotopes. A principle of the hydrogen transport pipe (heat pipe having hydrogen transport function) was proposed. It is comprised of the heat pipe and palladium alloy tubes as inlet, outlet, and the separation membrane of hydrogen. The operation was as follows: (1) gas was introduced into the heat pipe through the membrane in the evaporator; (2) the introduced gas was transported toward the condenser by the vapor flow; (3) the transported gas was swept and compressed to the end of the condenser by the vapor pressure; and (4) the compressed gas was exhausted from the heat pipe through the membrane in the condenser. The characteristics of the hydrogen transport pipe were examined for various working conditions. Basic performance concerning transportation, evacuation and compression was experimentally verified. Isotopic dihydrogen gases (H 2 and D 2 ) were used as feed gas for examining the intrinsic performance of the isotope separation by the hydrogen transport pipe. A simulated experiment for hydrogen isotope separation was carried out using a hydrogen-helium gas mixture. The hydrogen transport pipe has a potential for isotope separation and purification of hydrogen, deuterium and tritium in fusion reactor technology. (author)

  19. Effect of hydrogen addition on autoignited methane lifted flames

    KAUST Repository

    Choin, Byung Chul; Chung, Suk-Ho

    2012-01-01

    Autoignited lifted flames in laminar jets with hydrogen-enriched methane fuels have been investigated experimentally in heated coflow air. The results showed that the autoignited lifted flame of the methane/hydrogen mixture, which had an initial

  20. Catalyzed borohydrides for hydrogen storage

    Science.gov (United States)

    Au, Ming [Augusta, GA

    2012-02-28

    A hydrogen storage material and process is provided in which alkali borohydride materials are created which contain effective amounts of catalyst(s) which include transition metal oxides, halides, and chlorides of titanium, zirconium, tin, and combinations of the various catalysts. When the catalysts are added to an alkali borodydride such as a lithium borohydride, the initial hydrogen release point of the resulting mixture is substantially lowered. Additionally, the hydrogen storage material may be rehydrided with weight percent values of hydrogen at least about 9 percent.

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

    Science.gov (United States)

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

    2011-03-08

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

  2. Adsorption separation factors for hydrogen--deuterium (H/sub 2/-HD-D/sub 2/) mixtures on synthetic mordenite at 48 to 62/sup 0/K. [Reaction Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Parbuzin, V S; Kuryakov, Yu N

    1975-07-01

    The temperature dependence of selectivity has been determined for the adsorption of hydrogen isotopes by sodium mordenite. Heats and entropies of exchange of the isotopic molecules in the gas-zeolite system have been calculated from the experimental results. (auth)

  3. Color Changing Hydrogen Sensors

    Science.gov (United States)

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

    2015-01-01

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

  4. Hydrogen sensor

    Science.gov (United States)

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

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

  5. Container for hydrogen isotopes

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-12

    A container is described for storage, shipping and and dispensing of hydrogen isotopes such as hydrogen, deuterium, tritium, or mixtures of the same. The container is compact, safe against fracture or accident, and is reusable. It consists of an outer housing with suitable inlet and outlet openings and electrical feed elements, the housing containing an activated sorber material in the form, for example of titanium sponge or an activated zirconium aluminate cartridge. The gas to be stored is introduced into the chamber under conditions of heat and vacuum and is retained in the sorber material. Subsequently, it may be released by heating the unit to drive off the stored gas at desired rates.

  6. Container for hydrogen isotopes

    International Nuclear Information System (INIS)

    1976-01-01

    A container is described for storage, shipping and and dispensing of hydrogen isotopes such as hydrogen, deuterium, tritium, or mixtures of the same. The container is compact, safe against fracture or accident, and is reusable. It consists of an outer housing with suitable inlet and outlet openings and electrical feed elements, the housing containing an activated sorber material in the form, for example of titanium sponge or an activated zirconium aluminate cartridge. The gas to be stored is introduced into the chamber under conditions of heat and vacuum and is retained in the sorber material. Subsequently, it may be released by heating the unit to drive off the stored gas at desired rates

  7. Hydrogen system (hydrogen fuels feasibility)

    International Nuclear Information System (INIS)

    Guarna, S.

    1991-07-01

    This feasibility study on the production and use of hydrogen fuels for industry and domestic purposes includes the following aspects: physical and chemical properties of hydrogen; production methods steam reforming of natural gas, hydrolysis of water; liquid and gaseous hydrogen transportation and storage (hydrogen-hydride technology); environmental impacts, safety and economics of hydrogen fuel cells for power generation and hydrogen automotive fuels; relevant international research programs

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

    Science.gov (United States)

    Shepodd, Timothy J [Livermore, CA; Buffleben, George M [Tracy, CA

    2009-02-03

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

  9. Hail hydrogen

    International Nuclear Information System (INIS)

    Hairston, D.

    1996-01-01

    After years of being scorned and maligned, hydrogen is finding favor in environmental and process applications. There is enormous demand for the industrial gas from petroleum refiners, who need in creasing amounts of hydrogen to remove sulfur and other contaminants from crude oil. In pulp and paper mills, hydrogen is turning up as hydrogen peroxide, displacing bleaching agents based on chlorine. Now, new technologies for making hydrogen have the industry abuzz. With better capabilities of being generated onsite at higher purity levels, recycled and reused, hydrogen is being prepped for a range of applications, from waste reduction to purification of Nylon 6 and hydrogenation of specialty chemicals. The paper discusses the strong market demand for hydrogen, easier routes being developed for hydrogen production, and the use of hydrogen in the future

  10. Hydrogen embrittlement of steels: study and prevention

    International Nuclear Information System (INIS)

    Brass, A.M.; Chene, J.; Coudreuse, L.

    2000-01-01

    Hydrogen embrittlement of steels is one of the important reason of rupture of pieces in the industry (nuclear, of petroleum..). Indeed, there are a lot of situations which can lead to the phenomenon of hydrogen embrittlement: introduction of hydrogen in the material during the elaboration or during transformation or implementation processes (heat treatments, welding); use of steels when hydrogen or hydrogenated gaseous mixtures are present; hydrogen produced by electrolytic reactions (surface treatments, cathodic protection). The hydrogen embrittlement can appear in different forms which depend of a lot of parameters: material (state, composition, microstructure..); surrounding medium (gas, aqueous medium, temperature..); condition of mechanical solicitation (static, dynamic, cyclic..). The industrial phenomena which appear during cases of hydrogen embrittlement are more particularly described here. Several methods of steels studies are proposed as well as some possible ways for the prevention of hydrogen embrittlement risks. (O.M.)

  11. Modeling leaks from liquid hydrogen storage systems.

    Energy Technology Data Exchange (ETDEWEB)

    Winters, William Stanley, Jr.

    2009-01-01

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

  12. excess molar volumes, and refractive index of binary mixtures

    African Journals Online (AJOL)

    Preferred Customer

    because (a) water molecules have hydroxyl group which can make stronger hydrogen bonding than methanol and (b) water molecules and glycerol have suitable kinetic energy for bulk volumes at high temperature. Thus, the mixture of glycerol + water have big excess molar volume than methanol. The hydrogen bonding ...

  13. Low-cost process for hydrogen production

    Science.gov (United States)

    Cha, Chang Y.; Bauer, Hans F.; Grimes, Robert W.

    1993-01-01

    A method is provided for producing hydrogen and carbon black from hydrocarbon gases comprising mixing the hydrocarbon gases with a source of carbon and applying radiofrequency energy to the mixture. The hydrocarbon gases and the carbon can both be the products of gasification of coal, particularly the mild gasification of coal. A method is also provided for producing hydrogen an carbon monoxide by treating a mixture of hydrocarbon gases and steam with radio-frequency energy.

  14. Hydrogen detector

    International Nuclear Information System (INIS)

    Kumagaya, Hiromichi; Yoshida, Kazuo; Sanada, Kazuo; Chigira, Sadao.

    1994-01-01

    The present invention concerns a hydrogen detector for detecting water-sodium reaction. The hydrogen detector comprises a sensor portion having coiled optical fibers and detects hydrogen on the basis of the increase of light transmission loss upon hydrogen absorption. In the hydrogen detector, optical fibers are wound around and welded to the outer circumference of a quartz rod, as well as the thickness of the clad layer of the optical fiber is reduced by etching. With such procedures, size of the hydrogen detecting sensor portion can be decreased easily. Further, since it can be used at high temperature, diffusion rate is improved to shorten the detection time. (N.H.)

  15. Spectrophotometric determination of volautile inorganic hydrides in binary gaseous mixtures

    International Nuclear Information System (INIS)

    Rezchikov, V.G.; Skachkova, I.N.; Kuznetsova, T.S.; Khrushcheva, V.V.

    1985-01-01

    A study was made on possibility of single and continuons analysis of binary mixtures (hydride-gas) for the content of volatile inorganic hydrides (VIH) from absorption spectra in the 185-280 nm band. Dependences of the percentage of VIH transmission on the wavelength are presented. It is shown that the maximum of their absorption depends on the element-hydrogen the bond length and binding energy. Detection limit for boron hydride was established to be n x 10 -3 % vol at 185-190 nm wavelength. Technique for spectrophotometric hydride determination in binary mixtures with hydrogen, argon, helium was developed. The technique provides the continuous control of gaseous mixture composition

  16. Experimental results and analysis on hydrogen combustion

    International Nuclear Information System (INIS)

    Dorofeev, S.B.; Efimenko, A.A.; Kochurko, A.S.; Sidorov, V.P.; Bezmelnitsin, A.V.

    1994-01-01

    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 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 temperature between 300K and 650K at a fixed pressure of 0.1 MPa. Detonation cell size measurements provide clear evidence that the effect of hydrogen-air gas mixture temperature, in the range 300K to 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 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. Experiments were conducted to measure the rate of hydrogen oxidation in the absence of ignition sources at temperatures of 500K and 650K, for hydrogen-air mixtures of 15% and 50%, and for a mixture of equimolar hydrogen-air and 30% steam at 650K. The rate of hydrogen oxidation was found to be significant at 650K. Reduction of hydrogen concentration by chemical reaction from 50 to 44% hydrogen, and from 15 to 11% hydrogen, were observed on a time frame of minutes. The DeSoete rate equation predicts the 50% experiment very well, but greatly underestimates the reaction rate of the lean mixtures

  17. Optimal mixture experiments

    CERN Document Server

    Sinha, B K; Pal, Manisha; Das, P

    2014-01-01

    The book dwells mainly on the optimality aspects of mixture designs. As mixture models are a special case of regression models, a general discussion on regression designs has been presented, which includes topics like continuous designs, de la Garza phenomenon, Loewner order domination, Equivalence theorems for different optimality criteria and standard optimality results for single variable polynomial regression and multivariate linear and quadratic regression models. This is followed by a review of the available literature on estimation of parameters in mixture models. Based on recent research findings, the volume also introduces optimal mixture designs for estimation of optimum mixing proportions in different mixture models, which include Scheffé’s quadratic model, Darroch-Waller model, log- contrast model, mixture-amount models, random coefficient models and multi-response model.  Robust mixture designs and mixture designs in blocks have been also reviewed. Moreover, some applications of mixture desig...

  18. Some results of WNRE experiments on hydrogen combustion

    International Nuclear Information System (INIS)

    Liu, D.D.S.; MacFarlane, R.; Clegg, L.J.

    1981-01-01

    This paper describes some experimental results on hydrogen combustion related to the safety of nuclear reactor containment during a postulated loss-of-coolant accident and simultaneous loss-of-emergency-cooling accident. The following subjects are described: measurement of the burning velocity of hydrogen-air-steam mixtures; steam effect on the combustion of hydrogen-air mixtures near the lower flammability limit; and the effect of plasma, induced by laser breakdown at a wavelength of 1064 nm, on ignition behaviour in hydrogen-air mixtures with a view to understanding radiation effects on flammability limits

  19. Field effect-gas sensor for hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Plihal, M [Siemens A.G., Muenchen (Germany, F.R.). Forschungslaboratorium

    1977-01-01

    MIS diodes with palladium gate can be used to detect and to measure quantitatively the hydrogen concentration in gas mixtures. The dependence of the differential capacitance of these diodes on the partial pressure of hydrogen in nitrogen, oxygen and air is investigated. A theoretical model is developed which gives satisfactory agreement with most of the experimental results.

  20. Hydrogen highway

    International Nuclear Information System (INIS)

    Anon

    2008-01-01

    The USA Administration would like to consider the US power generating industry as a basis ensuring both the full-scale production of hydrogen and the widespread use of the hydrogen related technological processes into the economy [ru

  1. Hydrogen transport in the containment

    International Nuclear Information System (INIS)

    Royl, P.; Mueller, C.; Travis, J.R.; Wilson, T.

    1995-01-01

    For the description of transport phenomena in water vapor/hydrogen mixtures released in nuclear meltdown accidents, an integrated analytical model is being developed for LWR containments. Thermal and mechanical loads due to recombination and combustion are to be calculable. The 3-dimensional GASFLOW code was taken over from LANL in exchange for HDR experimental results and Battelle BMC program results. (orig.)

  2. Microfabricated hydrogen sensitive membranes

    Energy Technology Data Exchange (ETDEWEB)

    Naddaf, A.; Kraetz, L. [Lehrstuhl fuer Thermische Verfahrenstechnik, Technische Universitaet Kaiserslautern (Germany); Detemple, P.; Schmitt, S.; Hessel, V. [Institut fuer Mikrotechnik Mainz GmbH, Mainz (Germany); Faqir, N. [University of Jordan, Amman (Jordan); Bart, H.J.

    2009-01-15

    Thin, defect-free palladium, palladium/copper and palladium/silver hydrogen absorbing membranes were microfabricated. A dual sputtering technique was used to deposit the palladium alloy membranes of only 1 {mu}m thickness on a nonporous silicon substrate. Advanced silicon etching (ASE) was applied on the backside to create a mechanically stable support structure for the thin films. Performance evaluation was carried out for different gases in a temperature range of 20 C to 298 C at a constant differential pressure of 110 kPa at the two sides of the membrane. The composite membranes show an excellent permeation rate of hydrogen, which appears to be 0.05 Pa m{sup 3} s{sup -1} and 0.01.10{sup -3} Pa m{sup 3} s{sup -1} at 20 C for the microfabricated 23 % silver and the 53 % copper composite membranes, respectively. The selectivity to hydrogen over a gas mixture containing, in addition to hydrogen, carbon monoxide, carbon dioxide and nitrogen was measured. The mass spectrometer did not detect any CO{sub 2} or CO, showing that the membrane is completely hydrogen selective. The microfabricated membranes exhibit both high mechanical strength (they easily withstand pressures up to 4 bar) and high thermal stability (up to 650 C). (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  3. Manufacturing cycle for pure neon-helium mixture production

    International Nuclear Information System (INIS)

    Batrakov, B.P.; Kravchenko, V.A.

    1980-01-01

    The manufacturing cycle for pure neon-helium mixture production with JA-300 nitrogen air distributing device has been developed. Gas mixture containing 2-3% of neon-helium mixture (the rest is mainly nitrogen 96-97%) is selected out of the cover of the JA-300 column condensator and enters the deflegmator under the 2.3-2.5 atm. pressure. The diflegmator presents a heat exchange apparatus in which at 78 K liquid nitrogen the condensation of nitrogen from the mixture of gases entering from the JA-300 column takes place. The enriched gas mixture containing 65-70% of neon-helium mixture and 30-35% of nitrogen goes out from the deflegmator. This enriched neon-helium mixture enters the gasgoeder for impure (65-70%) neon-helium mixture. Full cleaning of-neon helium mixture of nitrogen is performed by means of an adsorber. As adsorbent an activated coal has been used. Adsorption occurs at the 78 K temperature of liquid nitrogen and pressure P=0.1 atm. As activated coal cooled down to nitrogen temperature adsorbs nitrogen better than neon and helium, the nitrogen from the mixture is completely adsorbed. Pure neon-helium mixture from the adsorber comes into a separate gasgolder. In one campaign the cycle allows obtaining 2 m 3 of the mixture. The mixture contains 0.14% of nitrogen, 0.01% of oxygen and 0.06% of hydrogen

  4. Thermal decomposition of silane to form hydrogenated amorphous Si

    Science.gov (United States)

    Strongin, M.; Ghosh, A.K.; Wiesmann, H.J.; Rock, E.B.; Lutz, H.A. III

    Hydrogenated amorphous silicon is produced by thermally decomposing silane (SiH/sub 4/) or other gases comprising H and Si, at elevated temperatures of about 1700 to 2300/sup 0/C, in a vacuum of about 10/sup -8/ to 10/sup -4/ torr. A gaseous mixture is formed of atomic hydrogen and atomic silicon. The gaseous mixture is deposited onto a substrate to form hydrogenated amorphous silicon.

  5. Kinetics of hydrogen isotope exchange reactions

    International Nuclear Information System (INIS)

    Gold, V.; McAdam, M.E.

    1975-01-01

    Under the influence of tritium β-radiation, 1,4-dioxan undergoes hydrogen exchange with the solvent water. The inhibition of the reaction by known electron scavengers (Ag + , Cu 2+ , Ni 2+ , Co 2+ , Zn 2+ , H 3 + O) and also by species with high reactivity towards hydroxyl radicals but negligible reactivity towards solvated electrons (N 3 - , Br - , SCN - ) has been examined in detail. γ-irradiation similarly induces hydrogen exchange. The action of scavengers is interpreted as requiring the involvement of two separately scavengeable primary radiolysis products in the sequence of reactions leading to exchange. The presence of electron scavengers, even at high concentration, does not totally inhibit the exchange, and a secondary exchange route, involving a low vacancy state of inhibitor cations, is considered responsible for the 'unscavengeable' portion of the reaction, by providing an alternative exchange route. Analogies are drawn between the exchange reaction and other radiation-induced reactions that are thought to involve spur processes. Some implication of radiation-chemical studies in water-alcohol mixtures are indicated. (author)

  6. Hydrogen economy

    Energy Technology Data Exchange (ETDEWEB)

    Pahwa, P.K.; Pahwa, Gulshan Kumar

    2013-10-01

    In the future, our energy systems will need to be renewable and sustainable, efficient and cost-effective, convenient and safe. Hydrogen has been proposed as the perfect fuel for this future energy system. The availability of a reliable and cost-effective supply, safe and efficient storage, and convenient end use of hydrogen will be essential for a transition to a hydrogen economy. Research is being conducted throughout the world for the development of safe, cost-effective hydrogen production, storage, and end-use technologies that support and foster this transition. This book discusses hydrogen economy vis-a-vis sustainable development. It examines the link between development and energy, prospects of sustainable development, significance of hydrogen energy economy, and provides an authoritative and up-to-date scientific account of hydrogen generation, storage, transportation, and safety.

  7. Development of proton conducting materials and membranes based on lanthanum tungstate for hydrogen separation from gas mixtures; Entwicklung protonenleitender Werkstoffe und Membranen auf Basis von Lanthan-Wolframat fuer die Wasserstoffabtrennung aus Gasgemischen

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, Janka

    2013-07-01

    Lanthanum tungstate La{sub 6-x}WO{sub 12-δ} (named LWO) is a ceramic material with mixed protonic electronic conductivity. Thereby it is a good candidate membrane material for hydrogen separation from synthesis gas in a fossil pre-combustion power plant. This work shows a material optimization by substitution targeted to clearly enhance the mixed conductivity and thereby the hydrogen flow through the LWO membrane. The first part of the work shows the synthesis and characterization of unsubstituted LWO. It points out that monophase LWO powder can be reproducibly synthesized. The La/W-ratio has to be considerably smaller than the nominal ratio of La/W = 6.0. It also depends on the used sintering conditions. Different relevant properties of LWO like stability in conditions close to application, thermal expansion, sintering behavior or microstructure were determined. Furthermore, the electrical conductivity of the material was investigated. LWO exhibits a prevailing protonic conductivity up to 750 C in wet atmospheres. Under dry atmospheres n-type conductivity was dominating. Oxygen ion and n-type conductivity dominated in wet and dry atmospheres above 750 C. The main part of the work is concerned with the development of new LWO based materials by substitutions. The aim is to achieve an improved mixed protonic electronic conductivity. Substitution elements for lanthanum side were Mg, Ca, Sr, Ba, Ce, Nd, Tb, Y and Al, while for the tungsten side Mo, Re and Ir were used. The total conductivity of the developed materials was investigated and compared to that of the unsubstituted LWO. The substitution of lanthanum led to no appreciable enhancement of the conductivity whereas the substitution of tungsten with 20 mol% molybdenum or 20 mol% rhenium clearly improved it. This caused a hydrogen flow about seven times higher for 20 mol% molybdenum- and about ten times higher for 20 mol% rhenium-substituted LWO in comparison with the unsubstituted LWO at 700 C. In the last part

  8. Changes in hydrogen isotope ratios in sequential plumage stages: an implication for the creation of isotope-base maps for tracking migratory birds.

    Science.gov (United States)

    Duxbury, J M; Holroyd, G L; Muehlenbachs, K

    2003-09-01

    Accurate reference maps are important in the use of stable-isotopes to track the movements of migratory birds. Reference maps created by the analysis of samples collected from young at the nest site are more accurate than simply referring to naturally occurring patterns of hydrogen isotope ratios created by precipitation cycles. Ratios of hydrogen isotopes in the nutrients incorporated early in the development of young birds can be derived from endogenous, maternal sources. Base-maps should be created with the analysis of tissue samples from hatchlings after local the isotopic signature of exogenous nutrients is dominant. Migratory species such as Peregrine Falcons are known to use endogenous sources in the creation of their eggs, therefore knowledge of what plumage stage best represents the local hydrogen ratios would assist in the planning of nest visits. We conducted diet manipulation experiments involving Japanese Quail and Peregrine Falcons to determine the plumage stage when hydrogen isotope ratios were indicative of a switch in their food source. The natal down of both the quail and falcons reflected the diet of breeding adult females. The hydrogen isotope ratios of a new food source were dominant in the juvenile down of the young falcons, although a further shift was detected in the final juvenile plumage. The juvenile plumage is grown during weeks 3-4 after hatch on Peregrine Falcons. Nest visits for the purpose of collecting feathers for isotope-base-map creation should be made around 4 weeks after the presumed hatch of the young falcons.

  9. Method for the enzymatic production of hydrogen

    Science.gov (United States)

    Woodward, J.; Mattingly, S.M.

    1999-08-24

    The present invention is an enzymatic method for producing hydrogen comprising the steps of: (a) forming a reaction mixture within a reaction vessel comprising a substrate capable of undergoing oxidation within a catabolic reaction, such as glucose, galactose, xylose, mannose, sucrose, lactose, cellulose, xylan and starch; the reaction mixture also comprising an amount of glucose dehydrogenase in an amount sufficient to catalyze the oxidation of the substrate, an amount of hydrogenase sufficient to catalyze an electron-requiring reaction wherein a stoichiometric yield of hydrogen is produced, an amount of pH buffer in an amount sufficient to provide an environment that allows the hydrogenase and the glucose dehydrogenase to retain sufficient activity for the production of hydrogen to occur and also comprising an amount of nicotinamide adenine dinucleotide phosphate sufficient to transfer electrons from the catabolic reaction to the electron-requiring reaction; (b) heating the reaction mixture at a temperature sufficient for glucose dehydrogenase and the hydrogenase to retain sufficient activity and sufficient for the production of hydrogen to occur, and heating for a period of time that continues until the hydrogen is no longer produced by the reaction mixture, wherein the catabolic reaction and the electron-requiring reactions have rates of reaction dependent upon the temperature; and (c) detecting the hydrogen produced from the reaction mixture. 8 figs.

  10. Liquids and liquid mixtures

    CERN Document Server

    Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S

    2013-01-01

    Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami

  11. Modeling low-temperature serpentinization reactions to estimate molecular hydrogen production with implications for potential microbial life on Saturn's moon Enceladus.

    Science.gov (United States)

    Zwicker, Jennifer; Smrzka, Daniel; Taubner, Ruth-Sophie; Bach, Wolfgang; Rittmann, Simon; Schleper, Christa; Peckmann, Jörn

    2017-04-01

    Serpentinization of ultramafic rocks attracts much interest in research on the origin of life on Earth and the search for life on extraterrestrial bodies including icy moons like Enceladus. Serpentinization on Earth occurs in peridotite-hosted systems at slow-spreading mid-ocean ridges, and produces large amounts of molecular hydrogen and methane. These reduced compounds can be utilized by diverse chemosynthetic microbial consortia as a metabolic energy source. Although many hydrothermal vents emit hot and acidic fluids today, it is more likely that life originated in the Archean at sites producing much cooler and more alkaline fluids that allowed for the synthesis and stability of essential organic molecules necessary for life. Therefore, a detailed understanding of water-rock interaction processes during low-temperature serpentinization is of crucial importance in assessing the life-sustaining potential of these environments. In the course of serpentinization, the metasomatic hydration of olivine and pyroxene produces various minerals including serpentine minerals, magnetite, brucite, and carbonates. Hydrogen production only occurs if ferrous iron within iron-bearing minerals is oxidized and incorporated as ferric iron into magnetite. The PHREEQC code was used to model the pH- and temperature-dependent dissolution of olivine and pyroxene to form serpentine, magnetite and hydrogen under pressure and temperature conditions that may exist on Saturn's icy moon Enceladus. Various model setups at 25 and 50°C were run to assess the influence of environmental parameters on hydrogen production. The results reveal that hydrogen production rates depend on the composition of the initial mineral assemblage and temperature. The current assumption is that there is a gaseous phase between Enceladus' ice sheet and subsurface ocean. To test various scenarios, model runs were conducted with and without the presence of a gas phase. The model results show that hydrogen production is

  12. Hydrogen safety

    International Nuclear Information System (INIS)

    Frazier, W.R.

    1991-01-01

    The NASA experience with hydrogen began in the 1950s when the National Advisory Committee on Aeronautics (NACA) research on rocket fuels was inherited by the newly formed National Aeronautics and Space Administration (NASA). Initial emphasis on the use of hydrogen as a fuel for high-altitude probes, satellites, and aircraft limited the available data on hydrogen hazards to small quantities of hydrogen. NASA began to use hydrogen as the principal liquid propellant for launch vehicles and quickly determined the need for hydrogen safety documentation to support design and operational requirements. The resulting NASA approach to hydrogen safety requires a joint effort by design and safety engineering to address hydrogen hazards and develop procedures for safe operation of equipment and facilities. NASA also determined the need for rigorous training and certification programs for personnel involved with hydrogen use. NASA's current use of hydrogen is mainly for large heavy-lift vehicle propulsion, which necessitates storage of large quantities for fueling space shots and for testing. Future use will involve new applications such as thermal imaging

  13. Predicting skin permeability from complex chemical mixtures

    International Nuclear Information System (INIS)

    Riviere, Jim E.; Brooks, James D.

    2005-01-01

    Occupational and environmental exposure to topical chemicals is usually in the form of complex chemical mixtures, yet risk assessment is based on experimentally derived data from individual chemical exposures from a single, usually aqueous vehicle, or from computed physiochemical properties. We present an approach using hybrid quantitative structure permeation relationships (QSPeR) models where absorption through porcine skin flow-through diffusion cells is well predicted using a QSPeR model describing the individual penetrants, coupled with a mixture factor (MF) that accounts for physicochemical properties of the vehicle/mixture components. The baseline equation is log k p = c + mMF + aΣα 2 H + bΣβ 2 H + sπ 2 H + rR 2 + vV x where Σα 2 H is the hydrogen-bond donor acidity, Σβ 2 H is the hydrogen-bond acceptor basicity, π 2 H is the dipolarity/polarizability, R 2 represents the excess molar refractivity, and V x is the McGowan volume of the penetrants of interest; c, m, a, b, s, r, and v are strength coefficients coupling these descriptors to skin permeability (k p ) of 12 penetrants (atrazine, chlorpyrifos, ethylparathion, fenthion, methylparathion, nonylphenol, ρ-nitrophenol, pentachlorophenol, phenol, propazine, simazine, and triazine) in 24 mixtures. Mixtures consisted of full factorial combinations of vehicles (water, ethanol, propylene glycol) and additives (sodium lauryl sulfate, methyl nicotinate). An additional set of 4 penetrants (DEET, SDS, permethrin, ricinoleic acid) in different mixtures were included to assess applicability of this approach. This resulted in a dataset of 16 compounds administered in 344 treatment combinations. Across all exposures with no MF, R 2 for absorption was 0.62. With the MF, correlations increased up to 0.78. Parameters correlated to the MF include refractive index, polarizability and log (1/Henry's Law Constant) of the mixture components. These factors should not be considered final as the focus of these studies

  14. Hydrogen Embrittlement

    Science.gov (United States)

    Woods, Stephen; Lee, Jonathan A.

    2016-01-01

    Hydrogen embrittlement (HE) is a process resulting in a decrease in the fracture toughness or ductility of a metal due to the presence of atomic hydrogen. In addition to pure hydrogen gas as a direct source for the absorption of atomic hydrogen, the damaging effect can manifest itself from other hydrogen-containing gas species such as hydrogen sulfide (H2S), hydrogen chloride (HCl), and hydrogen bromide (HBr) environments. It has been known that H2S environment may result in a much more severe condition of embrittlement than pure hydrogen gas (H2) for certain types of alloys at similar conditions of stress and gas pressure. The reduction of fracture loads can occur at levels well below the yield strength of the material. Hydrogen embrittlement is usually manifest in terms of singular sharp cracks, in contrast to the extensive branching observed for stress corrosion cracking. The initial crack openings and the local deformation associated with crack propagation may be so small that they are difficult to detect except in special nondestructive examinations. Cracks due to HE can grow rapidly with little macroscopic evidence of mechanical deformation in materials that are normally quite ductile. This Technical Memorandum presents a comprehensive review of experimental data for the effects of gaseous Hydrogen Environment Embrittlement (HEE) for several types of metallic materials. Common material screening methods are used to rate the hydrogen degradation of mechanical properties that occur while the material is under an applied stress and exposed to gaseous hydrogen as compared to air or helium, under slow strain rates (SSR) testing. Due to the simplicity and accelerated nature of these tests, the results expressed in terms of HEE index are not intended to necessarily represent true hydrogen service environment for long-term exposure, but rather to provide a practical approach for material screening, which is a useful concept to qualitatively evaluate the severity of

  15. Hydrogen millennium

    International Nuclear Information System (INIS)

    Bose, T.K.; Benard, P.

    2000-05-01

    The 10th Canadian Hydrogen Conference was held at the Hilton Hotel in Quebec City from May 28 to May 31, 2000. The topics discussed included current drivers for the hydrogen economy, the international response to these drivers, new initiatives, sustainable as well as biological and hydrocarbon-derived production of hydrogen, defense applications of fuel cells, hydrogen storage on metal hydrides and carbon nanostructures, stationary power and remote application, micro-fuel cells and portable applications, marketing aspects, fuel cell modeling, materials, safety, fuel cell vehicles and residential applications. (author)

  16. Reversible hydrogen storage materials

    Science.gov (United States)

    Ritter, James A [Lexington, SC; Wang, Tao [Columbia, SC; Ebner, Armin D [Lexington, SC; Holland, Charles E [Cayce, SC

    2012-04-10

    In accordance with the present disclosure, a process for synthesis of a complex hydride material for hydrogen storage is provided. The process includes mixing a borohydride with at least one additive agent and at least one catalyst and heating the mixture at a temperature of less than about 600.degree. C. and a pressure of H.sub.2 gas to form a complex hydride material. The complex hydride material comprises MAl.sub.xB.sub.yH.sub.z, wherein M is an alkali metal or group IIA metal, Al is the element aluminum, x is any number from 0 to 1, B is the element boron, y is a number from 0 to 13, and z is a number from 4 to 57 with the additive agent and catalyst still being present. The complex hydride material is capable of cyclic dehydrogenation and rehydrogenation and has a hydrogen capacity of at least about 4 weight percent.

  17. Container for hydrogen isotopes

    International Nuclear Information System (INIS)

    Solomon, D.E.

    1977-01-01

    A container for the storage, shipping and dispensing of hydrogen isotopes such as hydrogen, deuterium, tritium, or mixtures of the same which has compactness, which is safe against fracture or accident, and which is reusable is described. The container consists of an outer housing with suitable inlet and outlet openings and electrical feed elements, the housing containing an activated sorber material in the form, for example, of titanium sponge or an activated zirconium aluminate cartridge. The gas to be stored is introduced into the chamber under conditions of heat and vacuum and will be retained in the sorber material. Subsequently, it may be released by heating the unit to drive off the stored gas at desired rates

  18. Hydrogenating oils. [British patent

    Energy Technology Data Exchange (ETDEWEB)

    1938-08-31

    A safety fuel boiling within the limits 130/sup 0/ to 260/sup 0/C, is obtained by treating hydrocarbon mixtures boiling below 260/sup 0/C, and for the most part above 130/sup 0/C according to the process described in the parent Specification. A fraction boiling from 140/sup 0/ to 250/sup 0/ C, which has been distilled off from the liquefaction product obtained by the destructive hydrogenation of coal soaked with ferrous sulphate, is passed at 485/sup 0/C under a partial pressure of 1.5 atmos. and a hydrogen pressure of 50 atmos. over a catalyst consisting of nickel and tungsten sulphides. The gasification is only 2 to 5 percent and from the reaction product a fraction of the same boiling range as the initial material is distilled off with a yield of 85 percent and an octane number of 97.

  19. Hydrogen production using plasma processing

    International Nuclear Information System (INIS)

    Wagner, D.; Whidden, T.K.

    2006-01-01

    Plasma processing is a promising method of extracting hydrogen from natural gas while avoiding the greenhouse gas (GHG) production typical of other methods such as steam methane reforming. This presentation describes a plasma discharge process based that, in a single reactor pass, can yield hydrogen concentrations of up to 50 % by volume in the product gas mixture. The process is free of GHG's, does not require catalysts and is easily scalable. Chemical and morphological analyses of the gaseous and solid products of the process by gas-chromatography/mass-spectrometry, microscopic Raman analyses and electron microscopy respectively are reviewed. The direct production of hydrogen-enriched natural gas (HENG) as a fuel for low pollution internal combustion engines and its purification to high-purity hydrogen (99.99%) from the product gas by pressure swing adsorption (PSA) purifier beds are reviewed. The presentation reviews potential commercial applications for the technology

  20. Production of hydrogen by microbial fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Roychowdhury, S.; Cox, D.; Levandowsky, M.

    1988-01-01

    Production of hydrogen by defined and undefined bacterial cultures was studied, using pure sugars (glucose and maltose) or natural sources rich in either pure sugars or polysaccharides. The latter included sugar cane juice, corn pulp (enzymatically treated or untreated), and enzymatically treated paper. Mixed microbial flora from sewage and landfill sediments, as well as pure and mixed cultures of known coliform bacteria produced mixtures of hydrogen and carbon dioxide at 37/sup 0/C and 55/sup 0/C, with hydrogen concentrations as high as 87%. In the case of the pure glucose substrate, an average yield of 0.7 mol hydrogen per mol glucose was obtained.

  1. Closing the gap between socioeconomic and financial implications of residential and community level hydrogen-based energy systems: Incentives needed for a bridge to the future

    Science.gov (United States)

    Verduzco, Laura E.

    The use of hydrogen as an energy carrier has the potential to decrease the amount of pollutants emitted to the atmosphere, significantly reduce our dependence on imported oil and resolve geopolitical issues related to energy consumption. The current status of hydrogen technology makes it prohibitive and financially risky for most investors to commit the money required for large-scale hydrogen production. Therefore, alternative strategies such as small and medium-scale hydrogen applications should be implemented during the early stages of the transition to the hydrogen economy in order to test potential markets and technology readiness. While many analysis tools have been built to estimate the requirements of the transition to a hydrogen economy, few have focused on small and medium-scale hydrogen production and none has paired financial with socioeconomic costs at the residential level. The computer-based tool (H2POWER) presented in this study calculates the capacity, cost and socioeconomic impact of the systems needed to meet the energy demands of a home or a community using home and neighborhood refueling units, which are systems that can provide electricity and heat to meet the energy demands of either (1) a home and automobile or (2) a cluster of homes and a number of automobiles. The financial costs of the production, processing and delivery sub-systems that conform the refueling units are calculated using cost data of existing technology and normalizing them to calculate capital and net present cost. The monetary value of the externalities (socioeconomic analysis) caused by each system is calculated by H2POWER through a statistical analysis of the cost associated to various externalities. Additionally, H2POWER calculates the financial impact of different penalties and incentives (such as net metering, low interest loans, fuel taxes, and emission penalties) on the cost of the system from the point of view of a developer and a homeowner. In order to assess the

  2. Blending Hydrogen into Natural Gas Pipeline Networks. A Review of Key Issues

    Energy Technology Data Exchange (ETDEWEB)

    Melaina, M. W. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Antonia, O. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Penev, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-03-01

    This study assesses the potential to deliver hydrogen through the existing natural gas pipeline network as a hydrogen and natural gas mixture to defray the cost of building dedicated hydrogen pipelines. Blending hydrogen into the existing natural gas pipeline network has also been proposed as a means of increasing the output of renewable energy systems such as large wind farms.

  3. Genetic Evidence for Recent Population Mixture in India

    OpenAIRE

    Moorjani, Priya; Thangaraj, Kumarasamy; Patterson, Nick; Lipson, Mark; Loh, Po-Ru; Govindaraj, Periyasamy; Berger, Bonnie; Reich, David; Singh, Lalji

    2013-01-01

    Most Indian groups descend from a mixture of two genetically divergent populations: Ancestral North Indians (ANI) related to Central Asians, Middle Easterners, Caucasians, and Europeans; and Ancestral South Indians (ASI) not closely related to groups outside the subcontinent. The date of mixture is unknown but has implications for understanding Indian history. We report genome-wide data from 73 groups from the Indian subcontinent and analyze linkage disequilibrium to estimate ANI-ASI mixture ...

  4. 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...

  5. Vibrational relaxation in OCS mixtures

    International Nuclear Information System (INIS)

    Simpson, C.J.S.M.; Gait, P.D.; Simmie, J.M.

    1976-01-01

    Experimental measurements are reported of vibrational relaxation times which may be used to show whether there is near resonant vibration-rotation energy transfer between OCS and H 2 , D 2 or HD. Vibrational relaxation times have been measured in OCS and OCS mixtures over the temperature range 360 to 1000 K using a shock tube and a laser schlieren system. The effectiveness of the additives in reducing the relaxation time of OCS is in the order 4 He 3 He 2 2 and HD. Along this series the effect of an increase in temperature changes from the case of speeding up the rate with 4 He to retarding it with D 2 , HD and H 2 . There is no measurable difference in the effectiveness of n-D 2 and o-D 2 and little, or no, difference between n-H 2 and p-H 2 . Thus the experimental results do not give clear evidence for rotational-vibration energy transfer between hydrogen and OCS. This contrasts with the situation for CO 2 + H 2 mixtures. (author)

  6. Liquid hydrogen: back to basics

    Energy Technology Data Exchange (ETDEWEB)

    Sherif, S.A. [Dept. of Mechanical and Aerospace Engineering, Univ. of Florida, Florida (United States)

    2009-07-01

    'Full text': Liquid hydrogen is primarily used as a rocket fuel and is predestined for supersonic and hypersonic space vehicles to a large extent because it has the lowest boiling point density and the highest specific thrust of any known fuel. Its favorable characteristics include its high heating value per unit mass, its wide ignition range in hydrogen/oxygen or air mixtures, as well as its large flame speed and cooling capacity due to its high specific heat which permits very effective engine cooling and cooling the critical parts of the outer skin. Liquid hydrogen has some other important uses such as in high-energy nuclear physics and bubble chambers. The transport of hydrogen is vastly more economical when it is in liquid form even though cryogenic refrigeration and special Dewar vessels are required. Although liquid hydrogen can provide a lot of advantages, its uses are restricted in part because liquefying hydrogen by existing conventional methods consumes a large amount of energy (around 30% of its heating value). Liquefying 1 kg of hydrogen in a medium-size plant requires 10 to 13 kWh of electric energy. In addition, boil-off losses associated with the storage, transportation, and handling of liquid hydrogen can consume up to 40% of its available combustion energy. It is therefore important to search for ways that can improve the efficiency of the liquefiers and diminish the boil-off losses. This lecture gives an overview of the main issues associated with the production, storage, and handling of liquid hydrogen. Some discussion of promising ways of hydrogen liquefaction will also be presented. (author)

  7. Preparing valuable hydrocarbons by hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Pier, M

    1930-08-22

    A process is described for the preparation of valuable hydrocarbons by treatment of carbonaceous materials, like coal, tars, minerals oils, and their distillation and conversion products, and for refining of liquid hydrocarbon mixture obtained at raised temperature and under pressure, preferably in the presence of catalysts, by the use of hydrogen-containing gases, purified and obtained by distilling solid combustibles, characterized by the purification of the hydrogen-containing gases being accomplished for the purpose of practically complete removal of the oxygen by heating at ordinary or higher pressure in the presence of a catalyst containing silver and oxides of metals of group VI of the periodic system.

  8. Acoustic properties of organic acid mixtures in water

    Science.gov (United States)

    Macavei, I.; Petrisor, V.; Auslaender, D.

    1974-01-01

    The variation of the rate of propagation of ultrasounds in organic acid mixtures in water points to structural changes caused by interactions that take place under conditions of thermal agitation, at different acid concentrations. At the same time, a difference is found in the changes in velocity as a function of the length of the carbon chain of the acids in the mixture as a result of their effect on the groups of water molecules associated by hydrogen bonds.

  9. Cosolvent effect on the dynamics of water in aqueous binary mixtures

    Science.gov (United States)

    Zhang, Xia; Zhang, Lu; Jin, Tan; Zhang, Qiang; Zhuang, Wei

    2018-04-01

    Water rotational dynamics in the mixtures of water and amphiphilic molecules, such as acetone and dimethyl sulfoxide (DMSO), measured by femtosecond infrared, often vary non-monotonically as the amphiphilic molecule's molar fraction changes from 0 to 1. Recent study has attributed the non-ideal water rotation with concentration in DMSO-water mixtures to different microscopic hydrophilic-hydrophobic segregation structure in water-rich and water-poor mixtures. Interestingly, the acetone molecule has very similar molecular structure to DMSO, but the extremum of the water rotational time in the DMSO-water mixtures significantly shifts to lower concentration and the rotation of water is much faster than those in acetone-water mixtures. The simulation results here shows that the non-ideal rotational dynamics of water in both mixtures are due to the frame rotation during the interval of hydrogen bond (HB) switchings. A turnover of the frame rotation with concentration takes place as the structure transition of mixture from the hydrogen bond percolation structure to the hydrophobic percolation structure. The weak acetone-water hydrogen bond strengthens the hydrophobic aggregation and accelerates the relaxation of the hydrogen bond, so that the structure transition takes places at lower concentration and the rotation of water is faster in acetone-water mixture than in DMSO-water mixture. A generally microscopic picture on the mixing effect on the water dynamics in binary aqueous mixtures is presented here.

  10. Modeling of combustion products composition of hydrogen-containing fuels

    International Nuclear Information System (INIS)

    Assad, M.S.

    2010-01-01

    Due to the usage of entropy maximum principal the algorithm and the program of chemical equilibrium calculation concerning hydrogen--containing fuels are devised. The program enables to estimate the composition of combustion products generated in the conditions similar to combustion conditions in heat engines. The program also enables to reveal the way hydrogen fraction in the conditional composition of the hydrocarbon-hydrogen-air mixture influences the harmful components content. It is proven that molecular hydrogen in the mixture is conductive to the decrease of CO, CO 2 and CH x concentration. NO outlet increases due to higher combustion temperature and N, O, OH concentrations in burnt gases. (authors)

  11. Chain-Length Distribution and Hydrogen Isotopic Fraction of n-alkyl Lipids in Aquatic and Terrestrial Plants: Implications for Paleoclimate Reconstructions

    Science.gov (United States)

    Gao, L.; Littlejohn, S.; Hou, J.; Toney, J.; Huang, Y.

    2008-12-01

    Recent studies demonstrate that in lacustrine sediments, aquatic plant lipids (e.g., C22-fatty acid) record lake water D/H ratio variation, while long-chain fatty acids (C26-C32, major components of terrestrial plant leaf waxes), record D/H ratios of precipitation (especially in arid regions). However, there are insufficient literature data for the distribution and hydrogen isotopic fractionation of n-alkyl lipids in aquatic and terrestrial plants. In this study, we determined the chain-length distributions and D/H ratios of n-alkyl lipids from 17 aquatic plant species (9 emergent, 4 floating and 4 submerge species) and 13 terrestrial plant species (7 grasses and 6 trees) from Blood Pond, Massachusetts. Our results are consistent with previous studies and provide a solid basis for the paleoclimatic reconstruction using D/H ratios of aquatic and terrestrial plant biomarkers. In addition, systematic hydrogen isotopic analyses on leaf waxes, leaf, stem and soil waters from trees and grasses significantly advance our understanding of our previously observed large D/H ratio difference between tree and grass leaf waxes. Our data indicate that the observed difference is not due to differences in leaf water D/H ratios. In comparison with grasses, trees use greater proportion of D-enriched residual or stored carbohydrates (as opposed to current photosynthetic carbohydrates) for leaf wax biosynthesis, resulting in higher leaf wax D/H ratios. The residual carbohydrates are enriched in deuterium because of the preferential consumption of light-hydrogen substrates during plant metabolism.

  12. The analysis of mixtures of ortho and para-hydrogen and the catalytic conversion o.H{sub 2} {yields} p.H{sub 2}; Analyse des melanges d'ortho et para-hydrogenes et conversion catalytique o.H{sub 2} {yields} p.H{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Botter, F; Dirian, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1956-07-01

    This report describes experiments undertaken to measure the catalytic activity at - 195 deg. C of different types of absorbents for the heterogeneous conversion o.H{sub 2} {yields} p.H{sub 2}. The analytical method employed is a differential measurement of the thermal conductivity of the gas. In contrast to the classic method of FARKAS we have worked at room temperature (the difference of several per cent between the thermal conductivities of ortho and para-hydrogen at this temperature being found sufficiently great) and with a continuously recording system. The gas is at atmospheric pressure. We have investigated also the possibilities of an industrial katharometer which would allow a great extension to be given to this method of analysis. The instrument proved satisfactory. It has been checked that the paramagnetic conversion obeys first order kinetics. A certain number of absorbing substances were tested and amongst them, the active carbons, often used in the laboratory for the production of para-hydrogen, were shown to be the least active. A chromium oxide-aluminium oxide catalyst prepared from data available in the literature had a very great activity. In addition, some observations of the influence of adsorbed gases on the catalytic activity are reported: the comparison with the literature data is not easy due to the uncertainty in the physico-chemical nature of the absorbents used in the two cases. Finally, some bibliographic data relative to the properties of the two forms of hydrogen, their measurement, and the different mechanisms of interconversion are given. (author) [French] Le present rapport rend compte des essais entrepris en vue de determiner l'activite catalytique a - 195 deg. C de differents types d'absorbants vis-a-vis de la reaction de conversion heterogene o.H{sub 2} {yields} p.H{sub 2}. Le procede analytique utilise est la mesure differentielle de la conductibilite thermique du gas. Contrairement a la classique methode de FARKAS, on a opere d

  13. Polarized Light from the Sun: Unification of the Corona and Analysis of the Second Solar Spectrum — Further Implications of a Liquid Metallic Hydrogen Solar Model

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2015-07-01

    Full Text Available In order to account for the slight polarization of the continuum towards the limb, propo- nents of the Standard Solar Model (SSM must have recourse to electron or hydrogen- based scattering of light, as no other mechanism is possible in a gaseous Sun. Con- versely, acceptance that the solar body is comprised of condensed matter opens up new avenues in the analysis of this problem, even if the photospheric surface itself is viewed as incapable of emitting polarized light. Thus, the increased disk polarization, from the center to the limb, can be explained by invoking the scattering of light by the at- mosphere above the photosphere. The former is reminiscent of mechanisms which are known to account for the polarization of sunlight in the atmosphere of the Earth. Within the context of the Liquid Metallic Hydrogen Solar Model (LMHSM, molecules and small particles, not electrons or hydrogen atoms as required by the SSM, would primarily act as scattering agents in regions also partially comprised of condensed hy- drogen structures (CHS. In addition, the well-known polarization which characterizes the K-corona would become a sign of emission polarization from an anisotropic source, without the need for scattering. In the LMHSM, the K, F, and T- coronas can be viewed as emissive and reflective manifestations of a single corona l entity adopting a radially anisotropic structure, while slowly cooling with altitude above the photosphere. The presence of “dust particles”, advanced by proponents of the SSM, would no longer be required to explain the F and T-corona, as a single cooling structure would account for the properties of the K, F, and T coronas. At the same time, the polarized “Second Solar Spectrum”, characterized by the dominance of certain elemental or ionic spectral lines and an abundance of molecular lines, could be explained in the LMHSM, by first invoking interface polarization and coordination of these species with condensed matter

  14. Mechanochemical synthesis of nanostructured chemical hydrides in hydrogen alloying mills

    International Nuclear Information System (INIS)

    Wronski, Z.; Varin, R.A.; Chiu, C.; Czujko, T.; Calka, A.

    2007-01-01

    Mechanical alloying of magnesium metal powders with hydrogen in specialized hydrogen ball mills can be used as a direct route for mechanochemical synthesis of emerging chemical hydrides and hydride mixtures for advanced solid-state hydrogen storage. In the 2Mg-Fe system, we have successfully synthesized the ternary complex hydride Mg 2 FeH 6 in a mixture with nanometric Fe particles. The mixture of complex magnesium-iron hydride and nano-iron released 3-4 wt.%H 2 in a thermally programmed desorption experiment at the range 285-295 o C. Milling of the Mg-2Al powder mixture revealed a strong competition between formation of the Al(Mg) solid solution and the β-MgH 2 hydride. The former decomposes upon longer milling as the Mg atoms react with hydrogen to form the hydride phase, and drive the Al out of the solid solution. The mixture of magnesium dihydride and nano-aluminum released 2.1 wt.%H 2 in the temperature range 329-340 o C in the differential scanning calorimetry experiment. The formation of MgH 2 was suppressed in the Mg-B system; instead, a hydrogenated amorphous phase (Mg,B)H x , was formed in a mixture with nanometric MgB 2 . Annealing of the hydrogen-stabilized amorphous mixture produced crystalline MgB 2

  15. Device for removing hydrogen gas from the safety containment vessel of a nuclear reactor

    International Nuclear Information System (INIS)

    Stiefel, M.

    1983-01-01

    The safe processing of all concentrations of gas mixtures should be possible with such a device using a thermal recombiner of compact construction. A recombiner consisting of a metal case and diverter sheets situated in it is heated by induction. The incoming pipe for the gas mixture enriched with hydrogen and the outgoing pipe for the gas mixture with low hydrogen content are connected together by a three way valve. The third connection to the safety valve takes the larger port of the gas mixture with low hydrogen content back to the safety containment vessel. Sufficient amount of the gas mixture with low hydrogen content is taken via the three way valve to the safety containment vessel to ensure that the hydrogen content of the gas mixture taken to the recombiner remains below the 4% by volume limit. (orig./PW)

  16. Perception of trigeminal mixtures.

    Science.gov (United States)

    Filiou, Renée-Pier; Lepore, Franco; Bryant, Bruce; Lundström, Johan N; Frasnelli, Johannes

    2015-01-01

    The trigeminal system is a chemical sense allowing for the perception of chemosensory information in our environment. However, contrary to smell and taste, we lack a thorough understanding of the trigeminal processing of mixtures. We, therefore, investigated trigeminal perception using mixtures of 3 relatively receptor-specific agonists together with one control odor in different proportions to determine basic perceptual dimensions of trigeminal perception. We found that 4 main dimensions were linked to trigeminal perception: sensations of intensity, warmth, coldness, and pain. We subsequently investigated perception of binary mixtures of trigeminal stimuli by means of these 4 perceptual dimensions using different concentrations of a cooling stimulus (eucalyptol) mixed with a stimulus that evokes warmth perception (cinnamaldehyde). To determine if sensory interactions are mainly of central or peripheral origin, we presented stimuli in a physical "mixture" or as a "combination" presented separately to individual nostrils. Results showed that mixtures generally yielded higher ratings than combinations on the trigeminal dimensions "intensity," "warm," and "painful," whereas combinations yielded higher ratings than mixtures on the trigeminal dimension "cold." These results suggest dimension-specific interactions in the perception of trigeminal mixtures, which may be explained by particular interactions that may take place on peripheral or central levels. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. A straightforward method for Vacuum-Ultraviolet flux measurements: The case of the hydrogen discharge lamp and implications for solid-phase actinometry

    International Nuclear Information System (INIS)

    Fulvio, D.; Brieva, A. C.; Jäger, C.; Cuylle, S. H.; Linnartz, H.; Henning, T.

    2014-01-01

    Vacuum-Ultraviolet (VUV) radiation is responsible for the photo-processing of simple and complex molecules in several terrestrial and extraterrestrial environments. In the laboratory such radiation is commonly simulated by inexpensive and easy-to-use microwave-powered hydrogen discharge lamps. However, VUV flux measurements are not trivial and the methods/devices typically used for this purpose, mainly actinometry and calibrated VUV silicon photodiodes, are not very accurate or expensive and lack of general suitability to experimental setups. Here, we present a straightforward method for measuring the VUV photon flux based on the photoelectric effect and using a gold photodetector. This method is easily applicable to most experimental setups, bypasses the major problems of the other methods, and provides reliable flux measurements. As a case study, the method is applied to a microwave-powered hydrogen discharge lamp. In addition, the comparison of these flux measurements to those obtained by O 2 actinometry experiments allow us to estimate the quantum yield (QY) values QY 122  = 0.44 ± 0.16 and QY 160  = 0.87 ± 0.30 for solid-phase O 2 actinometry.

  18. A straightforward method for Vacuum-Ultraviolet flux measurements: The case of the hydrogen discharge lamp and implications for solid-phase actinometry

    Energy Technology Data Exchange (ETDEWEB)

    Fulvio, D., E-mail: daniele.fulvio@uni-jena.de, E-mail: dfu@oact.inaf.it; Brieva, A. C.; Jäger, C. [Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena (Germany); Cuylle, S. H.; Linnartz, H. [Raymond and Beverly Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, P.O. box 9513, 2300 RA Leiden (Netherlands); Henning, T. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)

    2014-07-07

    Vacuum-Ultraviolet (VUV) radiation is responsible for the photo-processing of simple and complex molecules in several terrestrial and extraterrestrial environments. In the laboratory such radiation is commonly simulated by inexpensive and easy-to-use microwave-powered hydrogen discharge lamps. However, VUV flux measurements are not trivial and the methods/devices typically used for this purpose, mainly actinometry and calibrated VUV silicon photodiodes, are not very accurate or expensive and lack of general suitability to experimental setups. Here, we present a straightforward method for measuring the VUV photon flux based on the photoelectric effect and using a gold photodetector. This method is easily applicable to most experimental setups, bypasses the major problems of the other methods, and provides reliable flux measurements. As a case study, the method is applied to a microwave-powered hydrogen discharge lamp. In addition, the comparison of these flux measurements to those obtained by O{sub 2} actinometry experiments allow us to estimate the quantum yield (QY) values QY{sub 122} = 0.44 ± 0.16 and QY{sub 160} = 0.87 ± 0.30 for solid-phase O{sub 2} actinometry.

  19. Greenhouse gas implications of using coal for transportation: Life cycle assessment of coal-to-liquids, plug-in hybrids, and hydrogen pathways

    International Nuclear Information System (INIS)

    Jaramillo, Paulina; Samaras, Constantine; Wakeley, Heather; Meisterling, Kyle

    2009-01-01

    Using coal to produce transportation fuels could improve the energy security of the United States by replacing some of the demand for imported petroleum. Because of concerns regarding climate change and the high greenhouse gas (GHG) emissions associated with conventional coal use, policies to encourage pathways that utilize coal for transportation should seek to reduce GHGs compared to petroleum fuels. This paper compares the GHG emissions of coal-to-liquid (CTL) fuels to the emissions of plug-in hybrid electric vehicles (PHEV) powered with coal-based electricity, and to the emissions of a fuel cell vehicle (FCV) that uses coal-based hydrogen. A life cycle approach is used to account for fuel cycle and use-phase emissions, as well as vehicle cycle and battery manufacturing emissions. This analysis allows policymakers to better identify benefits or disadvantages of an energy future that includes coal as a transportation fuel. We find that PHEVs could reduce vehicle life cycle GHG emissions by up to about one-half when coal with carbon capture and sequestration is used to generate the electricity used by the vehicles. On the other hand, CTL fuels and coal-based hydrogen would likely lead to significantly increased emissions compared to PHEVs and conventional vehicles using petroleum-based fuels.

  20. The Distribution of Hydrogen, Nitrogen, and Chlorine Radicals in the Lower Stratosphere: Implications for Changes in O3 due to Emission of NO(y) from Supersonic Aircraft

    Science.gov (United States)

    Salawitch, R. J.; Wofsy, S. C.; Wennberg, P. O.; Cohen, R. C.; Anderson, J. G.; Fahey, D. W.; Gao, R. S.; Keim, E. R.; Woodbridge, E. L.; Stimpfle, R. M.; hide

    1994-01-01

    In situ measurements of hydrogen, nitrogen, and chlorine radicals obtained in the lower stratosphere during the Stratospheric Photochemistry, Aerosols and Dynamics Expedition (SPADE) are compared to results from a photochemical model that assimilates measurements of radical precursors and environmental conditions. Models allowing for heterogeneous hydrolysis of N2O5 agree well with measured concentrations of NO and ClO, but concentrations of HO2 and OH are underestimated by 10 to 25%, concentrations of NO2 are overestimated by 10 to 30%, and concentrations of HCl are overestimated by a factor of 2. Discrepancies for [OH] and [HO2] are reduced if we allow for higher yields of O(sup 1)D) from 03 photolysis and for heterogeneous production of HNO2. The data suggest more efficient catalytic removal of O3 by hydrogen and halogen radicals relative to nitrogen oxide radicals than predicted by models using recommended rates and cross sections. Increases in [O3] in the lower stratosphere may be larger in response to inputs of NO(sub y) from supersonic aircraft than estimated by current assessment models.

  1. Questioning hydrogen

    International Nuclear Information System (INIS)

    Hammerschlag, Roel; Mazza, Patrick

    2005-01-01

    As an energy carrier, hydrogen is to be compared to electricity, the only widespread and viable alternative. When hydrogen is used to transmit renewable electricity, only 51% can reach the end user due to losses in electrolysis, hydrogen compression, and the fuel cell. In contrast, conventional electric storage technologies allow between 75% and 85% of the original electricity to be delivered. Even when hydrogen is extracted from gasified coal (with carbon sequestration) or from water cracked in high-temperature nuclear reactors, more of the primary energy reaches the end user if a conventional electric process is used instead. Hydrogen performs no better in mobile applications, where electric vehicles that are far closer to commercialization exceed fuel cell vehicles in efficiency, cost and performance. New, carbon-neutral energy can prevent twice the quantity of GHG's by displacing fossil electricity than it can by powering fuel cell vehicles. The same is true for new, natural gas energy. New energy resources should be used to displace high-GHG electric generation, not to manufacture hydrogen

  2. Saga of hydrogen civilization

    Energy Technology Data Exchange (ETDEWEB)

    Veziroglu, T.N. [Univ. of Miami, Coral Gables, FL (United States). Clean Energy Research Institute

    2008-09-30

    In the 1960s, air pollution in cities became an important issue hurting the health of people. The author became interested in environmental issues in general and air pollution in particular. He started studying possible vehicle fuels, with a view of determining the fuel which would cause little or no pollution. He particularly studied methanol, ethanol, ammonia and hydrogen as well as the gasohols (i.e., the mixtures of gasoline and methanol and/or ethanol). His investigation of fuels for transportation lasted five years (1967-1972). The result was that hydrogen is the cleanest fuel, and it is also the most efficient one. It would not produce CO (carbon monoxide), CO{sub 2} (carbon dioxide), SO{sub x}, hydrocarbons, soot and particulates. If hydrogen was burned in oxygen, it would not produce NO{sub x} either. If it burned in air, there would then be some NO{sub x} produced. Since the author has always believed that engineers and scientists should strive to find solutions to the problems facing humankind and the world, he established the Clean Energy Research Institute (CERI) at the University of Miami in 1973. The mission of the Institute was to find a solution or solutions to the energy problem, so the world economy can function properly and provide humankind with high living standards. To find clean forms of energy was also the mission of the Institute, so that they would not produce pollution and damage the health of flora, fauna and humans, as well as the environment of the planet Earth as a whole. CERI looked at all of the possible primary energy sources, including solar, wind, currents, waves, tides, geothermal, nuclear breeders and thermonuclear. Although they are much cleaner and would last much longer than fossil fuels, these sources were not practical for use. They were not storable or transportable by themselves, except nuclear. They could not be used as a fuel for transportation by themselves, except nuclear for marine transportation. In order to solve

  3. Iterative Mixture Component Pruning Algorithm for Gaussian Mixture PHD Filter

    Directory of Open Access Journals (Sweden)

    Xiaoxi Yan

    2014-01-01

    Full Text Available As far as the increasing number of mixture components in the Gaussian mixture PHD filter is concerned, an iterative mixture component pruning algorithm is proposed. The pruning algorithm is based on maximizing the posterior probability density of the mixture weights. The entropy distribution of the mixture weights is adopted as the prior distribution of mixture component parameters. The iterative update formulations of the mixture weights are derived by Lagrange multiplier and Lambert W function. Mixture components, whose weights become negative during iterative procedure, are pruned by setting corresponding mixture weights to zeros. In addition, multiple mixture components with similar parameters describing the same PHD peak can be merged into one mixture component in the algorithm. Simulation results show that the proposed iterative mixture component pruning algorithm is superior to the typical pruning algorithm based on thresholds.

  4. The prospects for hydrogen as an energy carrier: an overview of hydrogen energy and hydrogen energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, Marc A.; Koohi-Fayegh, Seama [Ontario Univ., Oshawa, ON (Canada). Inst. of Technology

    2016-02-15

    Hydrogen is expected to play a key role as an energy carrier in future energy systems of the world. As fossil-fuel supplies become scarcer and environmental concerns increase, hydrogen is likely to become an increasingly important chemical energy carrier and eventually may become the principal chemical energy carrier. When most of the world's energy sources become non-fossil based, hydrogen and electricity are expected to be the two dominant energy carriers for the provision of end-use services. In such a ''hydrogen economy,'' the two complementary energy carriers, hydrogen and electricity, are used to satisfy most of the requirements of energy consumers. A transition era will bridge the gap between today's fossil-fuel economy and a hydrogen economy, in which non-fossil-derived hydrogen will be used to extend the lifetime of the world's fossil fuels - by upgrading heavy oils, for instance - and the infrastructure needed to support a hydrogen economy is gradually developed. In this paper, the role of hydrogen as an energy carrier and hydrogen energy systems' technologies and their economics are described. Also, the social and political implications of hydrogen energy are examined, and the questions of when and where hydrogen is likely to become important are addressed. Examples are provided to illustrate key points. (orig.)

  5. The prospects for hydrogen as an energy carrier: an overview of hydrogen energy and hydrogen energy systems

    International Nuclear Information System (INIS)

    Rosen, Marc A.; Koohi-Fayegh, Seama

    2016-01-01

    Hydrogen is expected to play a key role as an energy carrier in future energy systems of the world. As fossil-fuel supplies become scarcer and environmental concerns increase, hydrogen is likely to become an increasingly important chemical energy carrier and eventually may become the principal chemical energy carrier. When most of the world's energy sources become non-fossil based, hydrogen and electricity are expected to be the two dominant energy carriers for the provision of end-use services. In such a ''hydrogen economy,'' the two complementary energy carriers, hydrogen and electricity, are used to satisfy most of the requirements of energy consumers. A transition era will bridge the gap between today's fossil-fuel economy and a hydrogen economy, in which non-fossil-derived hydrogen will be used to extend the lifetime of the world's fossil fuels - by upgrading heavy oils, for instance - and the infrastructure needed to support a hydrogen economy is gradually developed. In this paper, the role of hydrogen as an energy carrier and hydrogen energy systems' technologies and their economics are described. Also, the social and political implications of hydrogen energy are examined, and the questions of when and where hydrogen is likely to become important are addressed. Examples are provided to illustrate key points. (orig.)

  6. Destabilized and catalyzed borohydride for reversible hydrogen storage

    Science.gov (United States)

    Mohtadi, Rana F [Northville, MI; Nakamura, Kenji [Toyota, JP; Au, Ming [Martinez, GA; Zidan, Ragaiy [Alken, SC

    2012-01-31

    A process of forming a hydrogen storage material, including the steps of: providing a first material of the formula M(BH.sub.4).sub.X, where M is an alkali metal or an alkali earth metal, providing a second material selected from M(AlH.sub.4).sub.x, a mixture of M(AlH.sub.4).sub.x and MCl.sub.x, a mixture of MCl.sub.x and Al, a mixture of MCl.sub.x and AlH.sub.3, a mixture of MH.sub.x and Al, Al, and AlH.sub.3. The first and second materials are combined at an elevated temperature and at an elevated hydrogen pressure for a time period forming a third material having a lower hydrogen release temperature than the first material and a higher hydrogen gravimetric density than the second material.

  7. Hydrogen isotope ratios of terrestrial leaf wax n-alkanes from the Tibetan Plateau: Controls on apparent enrichment factors, effect of vapor sources and implication for altimetry

    Science.gov (United States)

    Zhang, Xiaolong; Xu, Baiqing; Günther, Franziska; Mügler, Ines; Lange, Markus; Zhao, Huabiao; Li, Jiule; Gleixner, Gerd

    2017-08-01

    Empirical evidence suggested that the altitudinal dependence of hydrogen isotope ratios of leaf wax n-alkanes (δDwax) can be used to estimate paleoaltitudinal changes. However, the application of δDwax-based paleoaltimetry remains difficult, as the impacts of evaporative, transpirative and biosynthetic processes on hydrogen isotope fractionations in changing environments and the influence of likely changing water vapor sources are not well explored. For this study, we sampled stream waters, soils and plant leaves along two transects spanning large gradients of altitude, precipitation amount, vapor source, temperature and vegetation type on the Tibetan Plateau (TP). δD values of stream water (as an approximation for δDp), soil water (δDsw) and plant leaf water (δDlw) as well as leaf wax n-alkanes were measured in order to quantify isotopic fractionations in the formation of leaf waxes. Most interestingly, we found a strong negative correlation between the evapotranspirative enrichment of leaf water against precipitation (εlw-p), which combines the effects of soil evaporation and leaf transpiration, and the biosynthetic hydrogen isotope fractionation (εwax-lw), which describes isotopic enrichment between leaf wax and leaf water. The relationship yields a steady apparent isotopic enrichment factor (εwax-p) between leaf wax and precipitation, which is independent from climatic parameters and has an average value of -107 ± 26‰ for grasses (monocotyledons) and -77 ± 22‰ for trees (dicotyledons). Since the terrestrial n-alkanes, especially n-C27 and n-C29, in sediments are derived from trees and grasses, the likely change of the vegetation type in the uplift of mountains can change the isotopic estimates by about ±30‰, which corresponds to an altitudinal change of ∼1600 m. We, therefore, suggest that hydrogen isotope ratio of sedimentary n-C31 alkane, which is mainly derived from grasses might be better proxies to reconstruct paleoaltitudes. Our large

  8. Predictions of glass transition temperature for hydrogen bonding biomaterials.

    Science.gov (United States)

    van der Sman, R G M

    2013-12-19

    We show that the glass transition of a multitude of mixtures containing hydrogen bonding materials correlates strongly with the effective number of hydroxyl groups per molecule, which are available for intermolecular hydrogen bonding. This correlation is in compliance with the topological constraint theory, wherein the intermolecular hydrogen bonds constrain the mobility of the hydrogen bonded network. The finding that the glass transition relates to hydrogen bonding rather than free volume agrees with our recent finding that there is little difference in free volume among carbohydrates and polysaccharides. For binary and ternary mixtures of sugars, polyols, or biopolymers with water, our correlation states that the glass transition temperature is linear with the inverse of the number of effective hydroxyl groups per molecule. Only for dry biopolymer/sugar or sugar/polyol mixtures do we find deviations due to nonideal mixing, imposed by microheterogeneity.

  9. Malabsorption of fructose-sorbitol mixtures. Interactions causing abdominal distress

    DEFF Research Database (Denmark)

    Rumessen, J J; Gudmand-Høyer, E

    1987-01-01

    Hydrogen breath tests were performed on 10 healthy adults after they had ingested a mixture of sorbitol and fructose, in which these substances were present in amounts corresponding to the individual absorption capacities. A significant malabsorption of this mixture was evident in 7 of 10 subjects....... The mixture caused mild to severe gastrointestinal distress in five subjects. When the carbohydrates were given separately, symptoms were absent. There was a significant correlation between the individual absorption capacities of fructose and of sorbitol. A mixture containing a similar amount of fructose......, but given as sucrose, and a similar amount of sorbitol was further given to four of the seven subjects showing malabsorption of the fructose-sorbitol mixture. Malabsorption now failed to appear, and symptoms were absent. These findings are of potential importance for the understanding of the physiologic...

  10. Hydrogen program overview

    Energy Technology Data Exchange (ETDEWEB)

    Gronich, S. [Dept. of Energy, Washington, DC (United States). Office of Utility Technologies

    1997-12-31

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

  11. Structural transition in alcohol–water binary mixtures: A ...

    Indian Academy of Sciences (India)

    WINTEC

    Abstract. The strengthening of the hydrogen bonding (H-bond) network as well as transition from the tetrahedral-like water network to the zigzag chain structure of alcohol upon increasing the alcohol con- centration in ethanol–water and tertiary butanol (TBA) – water mixtures have been studied by using both steady state ...

  12. Potential application of gas chromatography to the analysis of hydrogen isotopes

    International Nuclear Information System (INIS)

    Warner, D.K.; Sprague, R.E.; Bohl, D.R.

    1976-01-01

    Gas chromatography is used at Mound Laboratory for the analysis of hydrogen isotopic impurities in gas mixtures. This instrumentation was used to study the applicability of the gas chromatography technique to the determination of the major components of hydrogen isotopic gas mixtures. The results of this study, including chromatograms and precision data, are presented

  13. Carbon monoxide - hydrogen combustion characteristics in severe accident containment conditions. Final report

    International Nuclear Information System (INIS)

    2000-03-01

    production from a study for French reactors. For limestone-sand concrete, CO could be present in significant quantities (6% to 8%). For siliceous concrete, on the other hand, the CO concentration is generally small, of the order of 1%. Combustible gas generation (carbon monoxide and ex-vessel hydrogen) from core-concrete interactions is predicted in available codes (i.e., CORCON, WECHSL) but results are also highly plant specific. For this reason, the generation of CO is not examined in detail in this report, beyond defining a relevant range of compositions that bound the possible cases. This report reviews the knowledge base on CO/H 2 combustion from the perspective of assessing the potential combustion threat in containment during a severe reactor accident. Most aspects of classical combustion behaviour are discussed, including flammability limits, burning velocities, pressure development and detonability. Since CO and H 2 co-exist with copious quantities of CO 2 and steam in containment, diluent effects of CO 2 and steam on H 2 /CO combustion properties are also examined, where known. Where evident gaps in knowledge exist, they are identified and the safety implications of the resulting uncertainties are discussed: - Flammability limits for CO-H 2 -H 2 O-CO 2 -air mixtures can be determined accurately from Le Chatelier's rule or from empirical curve-fits to the experimental data. The presence of CO widens the flammability limits of hydrogen. - Burning velocities in CO 2 , H 2 , steam, and air mixtures can be determined reasonably accurately at low CO concentrations using available codes. However, available codes are not reliable at low hydrogen concentrations. There is a need for experimental determination of burning velocities for CO in the range of 0 to 10% and H2 in the range of 9 to 20%, and diluent (steam-CO 2 ) concentrations of up to 50%. Because burning velocity is a basic input parameter in the calculation of combustion pressure development, and since the

  14. USGS42 and USGS43: Human-hair stable hydrogen and oxygen isotopic reference materials and analytical methods for forensic science and implications for published measurement results

    Science.gov (United States)

    Coplen, T.B.; Qi, H.

    2012-01-01

    Because there are no internationally distributed stable hydrogen and oxygen isotopic reference materials of human hair, the U.S. Geological Survey (USGS) has prepared two such materials, USGS42 and USGS43. These reference materials span values commonly encountered in human hair stable isotope analysis and are isotopically homogeneous at sample sizes larger than 0.2 mg. USGS42 and USGS43 human-hair isotopic reference materials are intended for calibration of δ(2)H and δ(18)O measurements of unknown human hair by quantifying (1) drift with time, (2) mass-dependent isotopic fractionation, and (3) isotope-ratio-scale contraction. While they are intended for measurements of the stable isotopes of hydrogen and oxygen, they also are suitable for measurements of the stable isotopes of carbon, nitrogen, and sulfur in human and mammalian hair. Preliminary isotopic compositions of the non-exchangeable fractions of these materials are USGS42(Tibetan hair)δ(2)H(VSMOW-SLAP) = -78.5 ± 2.3‰ (n = 62) and δ(18)O(VSMOW-SLAP) = +8.56 ± 0.10‰ (n = 18) USGS42(Indian hair)δ(2)H(VSMOW-SLAP) = -50.3 ± 2.8‰ (n = 64) and δ(18)O(VSMOW-SLAP) = +14.11 ± 0.10‰ (n = 18). Using recommended analytical protocols presented herein for δ(2)H(VSMOW-SLAP) and δ(18)O(VSMOW-SLAP) measurements, the least squares fit regression of 11 human hair reference materials is δ(2)H(VSMOW-SLAP) = 6.085δ(2)O(VSMOW-SLAP) - 136.0‰ with an R-square value of 0.95. The δ(2)H difference between the calibrated results of human hair in this investigation and a commonly accepted human-hair relationship is a remarkable 34‰. It is critical that readers pay attention to the δ(2)H(VSMOW-SLAP) and δ(18)O(VSMOW-SLAP) of isotopic reference materials in publications, and they need to adjust the δ(2)H(VSMOW-SLAP) and δ(18)O(VSMOW-SLAP) measurement results of human hair in previous publications, as needed, to ensure all results on are on the same scales.

  15. Solvatochromism of naringenin in aqueous alcoholic mixtures

    Directory of Open Access Journals (Sweden)

    Faraji Mohammad

    2016-01-01

    Full Text Available The spectral change of naringenin was studied by Uv-vis spectrophotometric method in binary mixtures of water with methanol, ethanol and 1-propanol at 25°C. The effect of solvent was investigated by analysis of electron transition energy at the maximum absorption wavelength as a function of Kamlet and Taft parameters of mixtures by means of linear solvation energy relationships. The nonlinear response of solvatochromism was explained based on solute-solvent and solvent-solvent interactions. The possible preferential solvation of naringenin by each of solvents was studied through a modified preferential solvation model which considers the hydrogen bonding interactions between the prior solvents due to solvent-solvent interactions. The preferential solvation parameters and local mole fraction distribution around the solute were calculated. Results indicate that naringenin prefers to be more solvated by the complex solvating species and organic solvents than water.

  16. Urea and deuterium mixtures at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, M., E-mail: m.donnelly-2@sms.ed.ac.uk; Husband, R. J.; Frantzana, A. D.; Loveday, J. S. [Centre for Science at Extreme Conditions and School of Physics and Astronomy, The University of Edinburgh, Erskine Williamson Building, Peter Guthrie Tait Road, The King’s Buildings, Edinburgh EH9 3FD (United Kingdom); Bull, C. L. [ISIS, Rutherford Appleton Laboratory, Oxford Harwell, Didcot OX11 0QX (United Kingdom); Klotz, S. [IMPMC, CNRS UMR 7590, Université P and M Curie, 4 Place Jussieu, 75252 Paris (France)

    2015-03-28

    Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D{sub 2} mixtures that indicate no inclusion compound forms up to 3.7 GPa.

  17. Structure of selected basic zinc/copper (II) phosphate minerals based upon near-infrared spectroscopy--implications for hydrogen bonding.

    Science.gov (United States)

    Frost, Ray L; Reddy, B Jagannadha; Palmer, Sara J; Keeffe, Eloise C

    2011-03-01

    The NIR spectra of reichenbachite, scholzite and parascholzite have been studied at 298 K. The spectra of the minerals are different, in line with composition and crystal structural variations. Cation substitution effects are significant in their electronic spectra and three distinctly different electronic transition bands are observed in the near-infrared spectra at high wavenumbers in the 12,000-7600 cm(-1) spectral region. Reichenbachite electronic spectrum is characterised by Cu(II) transition bands at 9755 and 7520 cm(-1). A broad spectral feature observed for ferrous ion in the 12,000-9000 cm(-1) region both in scholzite and parascholzite. Some what similarities in the vibrational spectra of the three phosphate minerals are observed particularly in the OH stretching region. The observation of strong band at 5090 cm(-1) indicates strong hydrogen bonding in the structure of the dimorphs, scholzite and parascholzite. The three phosphates exhibit overlapping bands in the 4800-4000 cm(-1) region resulting from the combinations of vibrational modes of (PO(4))(3-) units. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Carbon and hydrogen isotopic composition of methane and C2+ alkanes in electrical spark discharge: implications for identifying sources of hydrocarbons in terrestrial and extraterrestrial settings.

    Science.gov (United States)

    Telling, Jon; Lacrampe-Couloume, Georges; Sherwood Lollar, Barbara

    2013-05-01

    The low-molecular-weight alkanes--methane, ethane, propane, and butane--are found in a wide range of terrestrial and extraterrestrial settings. The development of robust criteria for distinguishing abiogenic from biogenic alkanes is essential for current investigations of Mars' atmosphere and for future exobiology missions to other planets and moons. Here, we show that alkanes synthesized during gas-phase radical recombination reactions in electrical discharge experiments have values of δ(2)H(methane)>δ(2)H(ethane)>δ(2)H(propane), similar to those of the carbon isotopes. The distribution of hydrogen isotopes in gas-phase radical reactions is likely due to kinetic fractionations either (i) from the preferential incorporation of (1)H into longer-chain alkanes due to the more rapid rate of collisions of the smaller (1)H-containing molecules or (ii) by secondary ion effects. Similar δ(13)C(C1-C2+) and δ(2)H(C1-C2+) patterns may be expected in a range of extraterrestrial environments where gas-phase radical reactions dominate, including interstellar space, the atmosphere and liquid hydrocarbon lakes of Saturn's moon Titan, and the outer atmospheres of Jupiter, Saturn, Neptune, and Uranus. Radical recombination reactions at high temperatures and pressures may provide an explanation for the combined reversed δ(13)C(C1-C2+) and δ(2)H(C1-C2+) patterns of terrestrial alkanes documented at a number of high-temperature/pressure crustal sites.

  19. Study on the thermodynamics of the gadolinium-hydrogen binary system (H/Gd = 0.0–2.0) and implications to metallic gadolinium purification

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Kai; Li, Guoling [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Li, Jigang [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Liu, Yang [Department of Food Science, College of Arts and Science, Beijing Union University, Beijing, 100101 (China); Tian, Wenhuai, E-mail: wenhuaitian@ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, NO. 30, Xueyuan Road, Beijing 100083 (China); Zheng, Jie [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Li, Xingguo, E-mail: xgli@pku.edu.cn [Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)

    2016-07-15

    The thermodynamics of the gadolinium-hydrogen (Gd–H) binary system (H/Gd = 0.0–2.0) between 650 and 900 °C is studied by pressure composition isotherm measurement. Significant H dissolution in Gd is observed, up to H/Gd = 0.34 at 650 °C and 0.55 at 900 °C. The metal-rich phase boundary of nonstoichiometric gadolinium dihydride was found to occur with nominal composition of GdH{sub 1.80} at 650 °C and GdH{sub 1.53} at 900 °C. The results are in fairly good agreement with previous experimental work but with improved accuracy. The binary phase diagram is obtained using the CALPHAD method. The thermodynamic study here assists the understanding on the efficient deoxygenation effect by the H in Gd for Gd purification. - Highlights: • PCI measurements with high accuracy has been carried out. • A first assessment of Gd–H system has been carried out by the CALPHAD method. • A set of self-consistent thermodynamic parameters was derived for this system.

  20. HDT mixtures treatment strategies by gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Laquerbe, C.; Contreras, S.; Demoment, J. [Commissariat a l' Energie Atomique - CEA/Valduc, F-21121 Is sur Tille (France)

    2008-07-15

    Gas phase chromatographic processes are of interest for the separation of hydrogen isotopes from an HDT mixture. For a certain quantity, they are very competitive and present several benefits. Nevertheless no active packing material allows to have simultaneously good enrichment performances for tritium production and high decontamination capabilities for HD gases. The influence of the packing material is first described in this article. Then two specific processes (TCAP and Reverse Chromatography), each well adapted to perform one target, are presented. Finally, the problematic to propose an optimized treatment scheme associating these two processes is formulated. (authors)

  1. HDT mixtures treatment strategies by gas chromatography

    International Nuclear Information System (INIS)

    Laquerbe, C.; Contreras, S.; Demoment, J.

    2008-01-01

    Gas phase chromatographic processes are of interest for the separation of hydrogen isotopes from an HDT mixture. For a certain quantity, they are very competitive and present several benefits. Nevertheless no active packing material allows to have simultaneously good enrichment performances for tritium production and high decontamination capabilities for HD gases. The influence of the packing material is first described in this article. Then two specific processes (TCAP and Reverse Chromatography), each well adapted to perform one target, are presented. Finally, the problematic to propose an optimized treatment scheme associating these two processes is formulated. (authors)

  2. Hydroprocesssing of light gas oil - rape oil mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Walendziewski, Jerzy; Stolarski, Marek; Luzny, Rafal; Klimek, Bartlomiej [Faculty of Chemistry, Wroclaw University of Technology, ul. Gdanska 7/9, 50-310 Wroclaw (Poland)

    2009-05-15

    Two series of experiments of hydroprocessing of light gas oil - rape oil mixtures were carried out. The reactor feed was composed of raw material: first series - 10 wt.% rape oil and 90 wt.% of diesel oil; second series - 20 wt.% rape oil and 80 wt.% of diesel oil. Hydroprocessing of both mixtures was performed with the same parameter sets, temperature (320, 350 and 380 C), hydrogen pressure 3 and 5 MPa, LHSV = 2 h{sup -} {sup 1} and hydrogen feed ratio of 500 Nm{sup 3}/m{sup 3}. It was stated that within limited range it is possible to control vegetable oil hydrogenolysis in the presence of light gas oil fraction (diesel oil boiling range) through the proper selection of the process parameters. Hydrogenolysis of ester bonds and hydrogenation of olefinic bonds in vegetable oils are the main reactions in the process. Basic physicochemical properties of the obtained hydroprocessed products are presented. (author)

  3. Hydrogen separation membranes annual report for FY 2010.

    Energy Technology Data Exchange (ETDEWEB)

    Balachandran, U.; Dorris, S. E; Emerson, J. E.; Lee, T. H.; Lu, Y.; Park, C. Y.; Picciolo, J. J. (Energy Systems)

    2011-03-14

    The objective of this work is to develop dense ceramic membranes for separating hydrogen from other gaseous components in a nongalvanic mode, i.e., without using an external power supply or electrical circuitry. The goal of this project is to develop dense hydrogen transport membranes (HTMs) that nongalvanically (i.e., without electrodes or external power supply) separate hydrogen from gas mixtures at commercially significant fluxes under industrially relevant operating conditions. These membranes will be used to separate hydrogen from gas mixtures such as the product streams from coal gasification, methane partial oxidation, and water-gas shift reactions. Potential ancillary uses of HTMs include dehydrogenation and olefin production, as well as hydrogen recovery in petroleum refineries and ammonia synthesis plants, the largest current users of deliberately produced hydrogen. This report describes the results from the development and testing of HTM materials during FY 2010.

  4. Metastable hydrogen

    International Nuclear Information System (INIS)

    Dose, V.

    1982-01-01

    This paper deals with the basic physical properties of the metastable 2 2 sub(1/2) state of atomic hydrogen. Applications relying on its special properties, including measurement of the Lamb shift, production of spin-polarized protons and the measurement of molecular electric moments, are discussed. (author)

  5. Analysis of a Hydrogen Isotope separation process based on a continuous hydrogen-water exchange on column Transitions of Hydrogen

    International Nuclear Information System (INIS)

    Hodor, I.

    1988-01-01

    The analysed system consists of two plane-parallel walls, a water film flows down a wall, a catalyst layer is disposed on the other, a water vapour-hydrogen mixture moves up between the walls. A mathematical treatment is presented which permits to calculate the overall transfer coefficients and other parameters of practical interest from the local differential equations. (author)

  6. Carbon Dioxide-Free Hydrogen Production with Integrated Hydrogen Separation and Storage.

    Science.gov (United States)

    Dürr, Stefan; Müller, Michael; Jorschick, Holger; Helmin, Marta; Bösmann, Andreas; Palkovits, Regina; Wasserscheid, Peter

    2017-01-10

    An integration of CO 2 -free hydrogen generation through methane decomposition coupled with hydrogen/methane separation and chemical hydrogen storage through liquid organic hydrogen carrier (LOHC) systems is demonstrated. A potential, very interesting application is the upgrading of stranded gas, for example, gas from a remote gas field or associated gas from off-shore oil drilling. Stranded gas can be effectively converted in a catalytic process by methane decomposition into solid carbon and a hydrogen/methane mixture that can be directly fed to a hydrogenation unit to load a LOHC with hydrogen. This allows for a straight-forward separation of hydrogen from CH 4 and conversion of hydrogen to a hydrogen-rich LOHC material. Both, the hydrogen-rich LOHC material and the generated carbon on metal can easily be transported to destinations of further industrial use by established transport systems, like ships or trucks. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Mixtures Estimation and Applications

    CERN Document Server

    Mengersen, Kerrie; Titterington, Mike

    2011-01-01

    This book uses the EM (expectation maximization) algorithm to simultaneously estimate the missing data and unknown parameter(s) associated with a data set. The parameters describe the component distributions of the mixture; the distributions may be continuous or discrete. The editors provide a complete account of the applications, mathematical structure and statistical analysis of finite mixture distributions along with MCMC computational methods, together with a range of detailed discussions covering the applications of the methods and features chapters from the leading experts on the subject

  8. Performance Improvement of V-Fe-Cr-Ti Solid State Hydrogen Storage Materials in Impure Hydrogen Gas.

    Science.gov (United States)

    Ulmer, Ulrich; Oertel, Daria; Diemant, Thomas; Bonatto Minella, Christian; Bergfeldt, Thomas; Dittmeyer, Roland; Behm, R Jürgen; Fichtner, Maximilian

    2018-01-17

    Two approaches of engineering surface structures of V-Ti-based solid solution hydrogen storage alloys are presented, which enable improved tolerance toward gaseous oxygen (O 2 ) impurities in hydrogen (H 2 ) gas. Surface modification is achieved through engineering lanthanum (La)- or nickel (Ni)-rich surface layers with enhanced cyclic stability in an H 2 /O 2 mixture. The formation of a Ni-rich surface layer does not improve the cycling stability in H 2 /O 2 mixtures. Mischmetal (Mm, a mixture of La and Ce) agglomerates are observed within the bulk and surface of the alloy when small amounts of this material are added during arc melting synthesis. These agglomerates provide hydrogen-transparent diffusion pathways into the bulk of the V-Ti-Cr-Fe hydrogen storage alloy when the remaining oxidized surface is already nontransparent for hydrogen. Thus, the cycling stability of the alloy is improved in an O 2 -containing hydrogen environment as compared to the same alloy without addition of Mm. The obtained surface-engineered storage material still absorbs hydrogen after 20 cycles in a hydrogen-oxygen mixture, while the original material is already deactivated after 4 cycles.

  9. Hydrogen sulphide eruptions in the Atlantic Ocean off southern Africa: implications of a new view based on SeaWiFS satellite imagery

    Science.gov (United States)

    Weeks, Scarla J.; Currie, Bronwen; Bakun, Andrew; Peard, Kathleen R.

    2004-02-01

    Conventional wisdom has held that eruptions of toxic hydrogen sulphide that occur from time to time in the ocean off southwestern Africa were rather isolated near-coastal features, limited both in extent and in ecosystem-scale consequences. Now, however, it has become possible to identify sulphide outbreaks by satellite remote sensing. This new capability appears to lead to a complete revision of the conventional view, with some eruption episodes being observed to affect areas of ocean surface exceeding 20,000 km 2. The occurrences are also seen to be more frequent and longer lasting than previously supposed. Example sequences of Sea-viewing Wide Field of View (SeaWiFS) images are presented to indicate general classes of eruption types that are observed and to support discussion of potential eruption mechanisms. Certain methodological problems in interpreting effects on local productivity are outlined. Spatial configurations of eruptions indicate that simple upward advection in the upwelling process may not be a sufficient explanation for the range of eruption characteristics experienced. Eruptions seem often to be coincident with one of two contrasting types of atmospheric weather situation: either (1) increased intensity of wind driven coastal upwelling, or (2) indications of passage of a low pressure weather cell (e.g. interruption of coastal upwelling, sudden warming of the sea surface, rainfall in the hinterland). Such a pattern may imply that related lowering of hydrostatic pressure at depth may tend to trigger incipient eruptions. It also suggests an episodic mechanism driven by the buoyancy introduced by the effervescence of gases trapped by hydrostatic pressure within the sea-floor sediments. Connotations of these phenomena to the local ecology and to that of the entire Benguela Current regional ecosystem would appear to be major. Their relevance to the valuable but extremely variable fishery resource populations of the region, which have undergone drastic

  10. Simulation of hydrogen and hydrogen-assisted propane ignition in Pt catalyzed microchannel

    Energy Technology Data Exchange (ETDEWEB)

    Seshadri, Vikram; Kaisare, Niket S. [Department of Chemical Engineering, Indian Institute of Technology - Madras, Chennai 600 036 (India)

    2010-11-15

    This paper deals with self-ignition of catalytic microburners from ambient cold-start conditions. First, reaction kinetics for hydrogen combustion is validated with experimental results from the literature, followed by validation of a simplified pseudo-2D microburner model. The model is then used to study the self-ignition behavior of lean hydrogen/air mixtures in a Platinum-catalyzed microburner. Hydrogen combustion on Pt is a very fast reaction. During cold start ignition, hydrogen conversion reaches 100% within the first few seconds and the reactor dynamics are governed by the ''thermal inertia'' of the microburner wall structure. The self-ignition property of hydrogen can be used to provide the energy required for propane ignition. Two different modes of hydrogen-assisted propane ignition are considered: co-feed mode, where the microburner inlet consists of premixed hydrogen/propane/air mixtures; and sequential feed mode, where the inlet feed is switched from hydrogen/air to propane/air mixtures after the microburner reaches propane ignition temperature. We show that hydrogen-assisted ignition is equivalent to selectively preheating the inlet section of the microburner. The time to reach steady state is lower at higher equivalence ratio, lower wall thermal conductivity, and higher inlet velocity for both the ignition modes. The ignition times and propane emissions are compared. Although the sequential feed mode requires slightly higher amount of hydrogen, the propane emissions are at least an order of magnitude lower than the other ignition modes. (author)

  11. Hydrogen in CANDU fuel elements

    International Nuclear Information System (INIS)

    Sejnoha, R.; Manzer, A.M.; Surette, B.A.

    1995-01-01

    Unirradiated and irradiated CANDU fuel cladding was tested to compare the role of stress-corrosion cracking and of hydrogen in the development of fuel defects. The results of the tests are compared with information on fuel performance in-reactor. The role of hydriding (deuteriding) from the coolant and from the fuel element inside is discussed, and the control of 'hydrogen gas' content in the element is confirmed as essential for defect-free fuel performance. Finally, implications for fuel element design are discussed. (author)

  12. I-optimal mixture designs

    OpenAIRE

    GOOS, Peter; JONES, Bradley; SYAFITRI, Utami

    2013-01-01

    In mixture experiments, the factors under study are proportions of the ingredients of a mixture. The special nature of the factors in a mixture experiment necessitates specific types of regression models, and specific types of experimental designs. Although mixture experiments usually are intended to predict the response(s) for all possible formulations of the mixture and to identify optimal proportions for each of the ingredients, little research has been done concerning their I-optimal desi...

  13. Mixtures and interactions

    NARCIS (Netherlands)

    Groten, J.P.

    2000-01-01

    Drinking water can be considered as a complex mixture that consists of tens, hundreds or thousands of chemicals of which the composition is qualitatively and quantitatively not fully known. From a public health point of view it is most relevant to answer the question of whether chemicals in drinking

  14. Within-Site Variation in Feather Stable Hydrogen Isotope (δ2Hf) Values of Boreal Songbirds: Implications for Assignment to Molt Origin.

    Science.gov (United States)

    Nordell, Cameron J; Haché, Samuel; Bayne, Erin M; Sólymos, Péter; Foster, Kenneth R; Godwin, Christine M; Krikun, Richard; Pyle, Peter; Hobson, Keith A

    2016-01-01

    Understanding bird migration and dispersal is important to inform full life-cycle conservation planning. Stable hydrogen isotope ratios from feathers (δ2Hf) can be linked to amount-weighted long-term, growing season precipitation δ2H (δ2Hp) surfaces to create δ2Hf isoscapes for assignment to molt origin. However, transfer functions linking δ2Hp with δ2Hf are influenced by physiological and environmental processes. A better understanding of the causes and consequences of variation in δ2Hf values among individuals and species will improve the predictive ability of geographic assignment tests. We tested for effects of species, land cover, forage substrate, nest substrate, diet composition, body mass, sex, and phylogenetic relatedness on δ2Hf from individuals at least two years old of 21 songbird species captured during the same breeding season at a site in northeastern Alberta, Canada. For four species, we also tested for a year × species interaction effect on δ2Hf. A model including species as single predictor received the most support (AIC weight = 0.74) in explaining variation in δ2Hf. A species-specific variance parameter was part of all best-ranked models, suggesting variation in δ2Hf was not consistent among species. The second best-ranked model included a forage substrate × diet interaction term (AIC weight = 0.16). There was a significant year × species interaction effect on δ2Hf suggesting that interspecific differences in δ2Hf can differ among years. Our results suggest that within- and among-year interspecific variation in δ2Hf is the most important source of variance typically not being explicitly quantified in geographic assignment tests using non-specific transfer functions to convert δ2Hp into δ2Hf. However, this source of variation is consistent with the range of variation from the transfer functions most commonly being propagated in assignment tests of geographic origins for passerines breeding in North America.

  15. Ammonia/Hydrogen Mixtures in an SI-Engine

    DEFF Research Database (Denmark)

    Mørch, Christian Sandersen; Bjerre, Andreas; Gøttrup, Morten Piil

    2011-01-01

    to efficiency and power. A comparison with gasoline was made, which showed efficiencies and power increased due to the possibility of a higher compression ratio. The system analysis showed that it is possible to cover a major part of the necessary heat using the exhaust heat. It is proposed to reduce the high...

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

    Science.gov (United States)

    Cruden, Brett A.

    2016-01-01

    This paper describes the measurement of shock layer radiation in Hydrogen/Helium mixtures representative of that encountered by probes entering the Saturn atmosphere. Normal shock waves are measured in Hydrogen-Helium mixtures (89:11% by volume) at freestream pressures between 13-66 Pa (0.1-0.5 Torr) and velocities from 20-30 km/s. Radiance is quantified from the Vacuum Ultraviolet through Near Infrared. An induction time of several centimeters is observed where electron density and radiance remain well below equilibrium. Radiance is observed in front of the shock layer, the characteristics of which match the expected diffusion length of Hydrogen.

  17. Blending Hydrogen into Natural Gas Pipeline Networks: A Review of Key Issues

    Energy Technology Data Exchange (ETDEWEB)

    Melaina, M. W.; Antonia, O.; Penev, M.

    2013-03-01

    The United States has 11 distinct natural gas pipeline corridors: five originate in the Southwest, four deliver natural gas from Canada, and two extend from the Rocky Mountain region. This study assesses the potential to deliver hydrogen through the existing natural gas pipeline network as a hydrogen and natural gas mixture to defray the cost of building dedicated hydrogen pipelines.

  18. Hydrogen-enriched fuels

    Energy Technology Data Exchange (ETDEWEB)

    Roser, R. [NRG Technologies, Inc., Reno, NV (United States)

    1998-08-01

    NRG Technologies, Inc. is attempting to develop hardware and infrastructure that will allow mixtures of hydrogen and conventional fuels to become viable alternatives to conventional fuels alone. This commercialization can be successful if the authors are able to achieve exhaust emission levels of less than 0.03 g/kw-hr NOx and CO; and 0.15 g/kw-hr NMHC at full engine power without the use of exhaust catalysts. The major barriers to achieving these goals are that the lean burn regimes required to meet exhaust emissions goals reduce engine output substantially and tend to exhibit higher-than-normal total hydrocarbon emissions. Also, hydrogen addition to conventional fuels increases fuel cost, and reduces both vehicle range and engine output power. Maintaining low emissions during transient driving cycles has not been demonstrated. A three year test plan has been developed to perform the investigations into the issues described above. During this initial year of funding research has progressed in the following areas: (a) a cost effective single-cylinder research platform was constructed; (b) exhaust gas speciation was performed to characterize the nature of hydrocarbon emissions from hydrogen-enriched natural gas fuels; (c) three H{sub 2}/CH{sub 4} fuel compositions were analyzed using spark timing and equivalence ratio sweeping procedures and finally; (d) a full size pick-up truck platform was converted to run on HCNG fuels. The testing performed in year one of the three year plan represents a baseline from which to assess options for overcoming the stated barriers to success.

  19. Thermal neutron diffusion parameters in homogeneous mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Drozdowicz, K.; Krynicka, E. [Institute of Nuclear Physics, Cracow (Poland)

    1995-12-31

    A physical background is presented for a computer program which calculates the thermal neutron diffusion parameters for homogeneous mixtures of any compounds. The macroscopic absorption, scattering and transport cross section of the mixture are defined which are generally function of the incident neutron energy. The energy-averaged neutron parameters are available when these energy dependences and the thermal neutron energy distribution are assumed. Then the averaged diffusion coefficient and the pulsed thermal neutron parameters (the absorption rare and the diffusion constant) are also defined. The absorption cross section is described by the 1/v law and deviations from this behaviour are considered. The scattering cross section can be assumed as being almost constant in the thermal neutron region (which results from the free gas model). Serious deviations are observed for hydrogen atoms bound in molecules and a special study in the paper is devoted to this problem. A certain effective scattering cross section is found in this case on a base of individual exact data for a few hydrogenous media. Approximations assumed for the average cosine of the scattering angle are also discussed. The macroscopic parameters calculated are averaged over the Maxwellian energy distribution for the thermal neutron flux. An information on the input data for the computer program is included. (author). 10 refs, 4 figs, 5 tabs.

  20. Thermal neutron diffusion parameters in homogeneous mixtures

    International Nuclear Information System (INIS)

    Drozdowicz, K.; Krynicka, E.

    1995-01-01

    A physical background is presented for a computer program which calculates the thermal neutron diffusion parameters for homogeneous mixtures of any compounds. The macroscopic absorption, scattering and transport cross section of the mixture are defined which are generally function of the incident neutron energy. The energy-averaged neutron parameters are available when these energy dependences and the thermal neutron energy distribution are assumed. Then the averaged diffusion coefficient and the pulsed thermal neutron parameters (the absorption rare and the diffusion constant) are also defined. The absorption cross section is described by the 1/v law and deviations from this behaviour are considered. The scattering cross section can be assumed as being almost constant in the thermal neutron region (which results from the free gas model). Serious deviations are observed for hydrogen atoms bound in molecules and a special study in the paper is devoted to this problem. A certain effective scattering cross section is found in this case on a base of individual exact data for a few hydrogenous media. Approximations assumed for the average cosine of the scattering angle are also discussed. The macroscopic parameters calculated are averaged over the Maxwellian energy distribution for the thermal neutron flux. An information on the input data for the computer program is included. (author). 10 refs, 4 figs, 5 tabs

  1. Vertical observation of molecular hydrogen and carbon monoxide: Implication for non-photochemical H2 production at ocean surface and subsurface

    Science.gov (United States)

    Kawagucci, S.; Narita, T.; Obata, H.; Ogawa, H.; Gamo, T.

    2009-12-01

    Biological nitrogen fixation is a key metabolism controlling marine N-cycling and also known as a main H2 source. Recently, it was proposed that a monitoring of surface H2 concentration could be used quickly to figure out the spatial extent of biological nitrogen fixation activity without onboard incubation required for currently used methods for detecting the activity. However, H2 behavior in ocean water was still unresolved. This study carried out vertical observation of H2 and CO concentrations in south of Japan, western North Pacific. Because carbon monoxide, CO, in seawater has no relation with nitrogen fixation metabolism and is produced dominantly by the photochemical reaction, which is an altanative H2 source, simultaneous observation and comparison of H2 and CO concentration is helpful to investigate H2 behavior in ocean water. Reductive gases in seawater were observed during the R/V Tansei-maru KT-08-14 cruise by using a wired CTD-CMS (CTD-carousel multiple sampling) system to conduct vertical sampling (at most 200 m depth) and by using a plastic bucket for sampling surface seawater. The sample in the Niskin-X bottle was directed to the bottom of a 120 mL brown-colored glass vial allowed to overflow by 2 volumes before the tube was slowly withdrawn. After the addition of 0.5 mL HgCl2-saturated solution for poisoning, the PTFE-lined butyl-gum septum was used to cap the vials. Molecular hydrogen (H2) and carbon monoxide (CO) were analyzed at an onboard laboratory within 6 hours after subsampling. 20 mL of sample water was substituted by 20 mL of H2- and CO-free air using a gas-tight syringe; then the vial was put on an automatic shaker and shaken upside down for 6 minutes to achieve a complete equilibrium between the dissolved and head space gases in the vial. The equilibrated headspace was taken by another gas-tight syringe and then injected into a gas chromatograph equipped with a trace reduced gas detector. Vertical distribution of dissolved H2 and CO

  2. Co-pyrolysis of wood biomass and synthetic polymers mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Sharypov, V.I.; Beregovtsova, N.G.; Kuznetsov, B.N.; Baryshnikov, S.V. [Institute of Chemistry and Chemical Technology SB RAS, K. Marx Str., Krasnoyarsk 660049 (Russian Federation); Cebolla, V.L. [Instituto de Carboquimica, CSIC, Zaragoza (Spain); Weber, J.V.; Collura, S.; Finqueneisel, G.; Zimny, T. [Laboratoire de Chimie et Applications, Universite de Metz, IUT, rue V. Demange, 57500 Saint Avold (France)

    2006-06-01

    The pyrolysis in a hydrogen atmosphere of pine wood and synthetic polymers (polyethylene and polypropylene) mixtures was studied in a rotating autoclave. The effects of reaction temperature, wood/polymers mixture composition and catalysts, on the mixtures conversion into liquids and gases were established and discussed. The used catalysts were pyrrhotite and haematite materials activated by mechanochemical treatment. In the co-liquefaction processes the interaction between fragments of wood and polymers thermal decomposition took place. This results in non-additive increase of the wood/polymers conversion degree by 10-15wt.% and of the yield of distillate fractions by 14-19wt.%. Iron ore materials were found catalytically active in the process of hydropyrolysis of wood/polymers mixtures. By using these catalysts a significant increase of the distillable liquids amounts (by 14-21wt.%) and a sharp decrease of olefins and cycloparaffins content (by approximately two to three times) were observed. (author)

  3. Enhancement of nuclear reaction rates in asymmetric binary ionic mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Clerouin, J.; Arnault, P.; Desbiens, N. [CEA, DAM, DIF, Arpajon (France); White, A.; Ticknor, C.; Kress, J.D.; Collins, L.A. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM (United States)

    2017-11-15

    Using orbital-free molecular dynamics simulations we study the structure and dynamics of increasingly asymmetric mixtures such as hydrogen-carbon, hydrogen-aluminium, hydrogen-copper, and hydrogen-silver. We show that, whereas the heavy component structure is close to an effective one-component plasma (OCP), the light component appears more structured than the corresponding OCP. This effect is related to the crossover towards a Lorentz-type diffusion triggered by strongly coupled, highly charged heavy ions, and witnessed by the change of temperature scaling laws of diffusion. This over-correlation translates into an enhancement of nuclear reaction rates much higher than its classical OCP counterpart. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Benzene adsorption and hydrogenation on Pd-Ru alloy by pulse chromatography

    International Nuclear Information System (INIS)

    Dobrokhotov, V.G.; Pavlova, L.F.; Gryaznov, V.M.

    1983-01-01

    Pulse chromatography has been applied to investigate benzene adsorption and hydrogenation on the Walls of a capillary of the Pd-6% Ru alloy at different hydrogen contents in the alloy and various methods of hydrogen supply: as a mixture with benzene vapors or by diffusion through the walls of the capillary. It is stated that reversible adsorption of benzene vapors on the Pd-6% Ru alloy at 303 K under the conditions of the β-phase existence in the alloy-hydrogen system does not change whereas in the region of the α-phase existence it slightly increases with a growth of hydrogen pressure. Strongly adsorbed benzene occupies approximately 7% of the surface. Only strongly adsorbed benzene is hydrogenated on the α-phase of the alloy-hydrogen system. Hydrogen supply to the hydrogenation zone by diffusion throUgh the alloy results in supersaturation of the surface active in the reaction of benzene hydrogenation with a chemisorbed hydrogen form

  5. High and rapid hydrogen release from thermolysis of ammonia borane near PEM fuel cell operating temperature

    Science.gov (United States)

    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. The hydrogen; L'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The hydrogen as an energy system represents nowadays a main challenge (in a scientific, economical and environmental point of view). The physical and chemical characteristics of hydrogen are at first given. Then, the challenges of an hydrogen economy are explained. The different possibilities of hydrogen production are described as well as the distribution systems and the different possibilities of hydrogen storage. Several fuel cells are at last presented: PEMFC, DMFC and SOFC. (O.M.)

  7. Mixture based outlier filtration

    Czech Academy of Sciences Publication Activity Database

    Pecherková, Pavla; Nagy, Ivan

    2006-01-01

    Roč. 46, č. 2 (2006), s. 30-35 ISSN 1210-2709 R&D Projects: GA MŠk 1M0572; GA MDS 1F43A/003/120 Institutional research plan: CEZ:AV0Z10750506 Keywords : data filtration * system modelling * mixture models Subject RIV: BD - Theory of Information http://library.utia.cas.cz/prace/20060165.pdf

  8. Electrochemistry of isopolytungstate mixtures

    International Nuclear Information System (INIS)

    Borzenko, M.I.; Botukhova, G.N.; Tsirlina, G.A.; Petrii, O.A.

    2008-01-01

    Solutions of isopolytungstates are of interest as the precursors for electrodeposited rechargeable tungsten oxides, and also in relation to hydrogen evolution catalysis. Understanding of isopolytungstate electrochemistry is complicated by numerous pH-dependent equilibria. This paper presents some data of dc polarography and UV absorption spectroscopy for solutions always containing several types of coexisting isopolytungstate species, in order to understand the individual electrochemical reactivity of certain isopolyanions

  9. Thermodynamics of mixtures containing amines

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan Antonio [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain)], E-mail: jagl@termo.uva.es; Mozo, Ismael; Garcia de la Fuente, Isaias; Cobos, Jose Carlos [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain); Riesco, Nicolas [Department of Chemical Engineering, Loughborough University, Loughborough, LE113TU Leicestershire (United Kingdom)

    2008-01-30

    Mixtures with dimethyl or trimethylpyridines and alkane, aromatic compound or 1-alkanol have been examined using different theories: DISQUAC, Flory, the concentration-concentration structure factor, S{sub CC}(0), or the Kirkwood-Buff formalism. DISQUAC represents fairly well the available experimental data, and improves theoretical calculations from Dortmund UNIFAC. Two important effects have been investigated: (i) the effect of increasing the number of methyl groups attached to the aromatic ring of the amine; (ii) the effect of modifying the position of the methyl groups in this ring. The molar excess enthalpy, H{sup E}, and the molar excess volume, V{sup E}, decrease in systems with alkane or methanol as follows: pyridine > 3-methylpyridine > 3,5-dimethylpyridine and pyridine > 2-methylpyridine > 2,4-dimethylpyridine > 2,4,6-trimethylpyridine, which has been attributed to a weakening of the amine-amine interactions in the same sequences. This is in agreement with the relative variation of the effective dipole moment, {mu}-bar, and of the differences between the boiling temperature of a pyridine base and that of the homomorphic alkane. For heptane solutions, the observed H{sup E} variation, H{sup E} (3,5-dimethylpyridine) > H{sup E} (2,4-dimethylpyridine) > H{sup E} (2,6-dimethylpyridine), is explained similarly. Calculations on the basis of the Flory model confirm that orientational effects become weaker in systems with alkane in the order: pyridine > methylpyridine > dimethylpyridine > trimethylpyridine. S{sub CC}(0) calculations show that steric effects increase with the number of CH{sub 3}- groups in the pyridine base, and that the steric effects exerted by methyl groups in positions 2 and 6 are higher than when they are placed in positions 3 and 5. The hydrogen bond energy in methanol mixtures is independent of the pyridine base, and it is estimated to be -35.2 kJ mol{sup -1}. Heterocoordination in these solutions is due in part to size effects. Their

  10. Hydrogen adsorption on partially oxidised microporous carbons

    International Nuclear Information System (INIS)

    J B Parra; C O Ania; C J Duran Valle; M L Sanchez; C Otero Arean

    2005-01-01

    The search for cost effective adsorbents for large scale gas separation, storage and transport constitutes a present day strategic issue in the energy sector, propelled mainly by the potential use of hydrogen as an energy vector in a sustainable (and cleaner) energy scenario. Both, activated carbons and carbon based nano-structured materials have been proposed as potential candidates for reversible hydrogen storage in cryogenically cooled vessels. For that purpose, surface modification so as to enhance the gas solid interaction energy is desirable. We report on hydrogen adsorption on microporous (active) carbons which have been partially oxidised with nitric acid and ammonium persulfate. From the corresponding hydrogen adsorption isotherms (Fig. 1) an isosteric heat of about 3 kJ mol -1 was derived. This value is in agreement with that of about 3 to 4 kJ mol -1 obtained by quantum chemical calculations on the interaction between the hydrogen molecule and simple model systems (Fig. 2) of both, hydroxyl and carboxyl groups. Further research is in progress with a view to further increases the gas solid interaction energy. However, the values so far obtained are significantly larger than the liquefaction enthalpy of hydrogen: 0.90 kJ mol -1 ; and this is relevant to both, hydrogen separation from gas mixtures and cryogenic hydrogen storage. (authors)

  11. Method for separating gaseous mixtures of matter

    International Nuclear Information System (INIS)

    Schuster, E.; Kersting, A.

    1979-01-01

    Molecules to be separated from a mixture of matter of a chemical component are excited in a manner known per se by narrow-band light sources, and a chemical reaction partner for reacting with these molecules is admixed while supplied with energy by electromagnetic radiation or heating, and as additionally required for making chemical reactions possible. A method is described for separating gaseous mixtures of matter by exciting the molecules to be separated with laser radiation and causing the excited species to react chemically with a reaction partner. It may be necessary to supply additional energy to the reaction partner to make the chemical reaction possible. The method is applicable to the separation of hydrogen isotopes by the bromination of normal methanol in a mixture normal methanol and deuterated methanol; of uranium isotope by the reactions of UF 6 with SF 4 , SiCl 4 , HCl, or SO 2 ; and of boron isotopes by the reaction of BH 3 with NH 3

  12. Effect of Mixture Pressure and Equivalence Ratio on Detonation Cell Size for Hydrogen-Air Mixtures

    Science.gov (United States)

    2015-06-01

    In order to design combustion chambers for detonating engines, specifically PDEs and RDEs , the cell size is needed. Higher than atmospheric...8 Figure 4. RDE dimensions ................................................................................................ 11...Technology DDT Deflagration to Detonation MAPE Mean Absolute Percent Error PDE Pulsed Detonation Engine RDE Rotating Detonation Engine ZND

  13. Mixture for plugging absorption zones

    Energy Technology Data Exchange (ETDEWEB)

    Sitinkov, G V; Kovalenko, N G; Makarov, L V; Zinnatulchin, Ts Kh

    1981-01-17

    A mixture is proposed for plugging absorption zones. The mixture contains synthetic polymer and a solvent. So as to increase the penetrability of the mixture through a reduction in its viscosity and an increase in insulation properties, the compound contains either Capron or Neilon as the synthetic polyamide resin polmyer, and concentrated chloride as the solvent. The mixture is prepared in a special AzINMASh-30 unit (acid cart). After the mixture has been produced, it is injected into the borehole by means of an acid cart pump. So as to prevent coaggulation at the point when the mixture in injected into the stratum through tubes, the mixture is placed betwen chemically inert fluids, for example, a clay mortar. The inert and compressed fluids are injected by means of a cementing unit. The entire process of production and application of the mixture is simple and fully automated through the use of well-known equipment.

  14. Investigation of the explosion hazards of hydrogen sulphide

    International Nuclear Information System (INIS)

    Saber, A.J.; Sulmistras, A.; Moen, I.O.; Thibault, P.A.

    1986-03-01

    The results of Phase I of an investigation directed towards quantifying the explosion hazards of hydrogen sulphide in air are described. The first phase is focussed on detonation in free hydrogen sulphide/air clouds. Detonation properties, including velocity and pressure, have been calculated and compared with experimental results. The observed detonation structure together with critical tube tests tests are used to assess the detonability of hydrogen sulphide/air mixtures relative to hydrogen and common hydrocarbon gases. Detailed chemical kinetic modelling of hydrogen sulphide combustion in air has been performed to correlate the detonation cell size data and to determine the influence of water vapour on the detonability of hydrogen sulphide in air. Calculations of the blast wave properties for detonation of a hydrogen sulphide/air cloud provide the data required to assess the blast effects of such explosions

  15. Membrane pumping technology, helium and hydrogen isotopes separation in the fusion hydrogen

    International Nuclear Information System (INIS)

    Pigarov, A.Yu.; Pistunovich, V.I.; Busnyuk, A.O.

    1994-01-01

    A gas pumping system for the ITER, improved by implementation of superpermeable membranes for selective hydrogen isotope exhaust, is considered. The study of the pumping capability of a niobium membrane for a hydrogen-helium mixture has been fulfilled. The membrane superpermeability can be only realized for atomic hydrogen. Helium does not pass through the membrane, and its presence does not affect the hydrogen pumping. A detailed Monte Carlo simulation of gas behavior for the experimental facility has been done. The probability of permeation for a hydrogen atom for one collision with the membrane is ∼0.1; the same probability of molecule permeation is ∼10 -5 . The probability for atomization, i.e. re-emission of an atomizer is ∼0.2; the probability of recombination of an atom is ∼0.2

  16. GOTHIC analysis of post-accident hydrogen mixing behaviour in CANDU fuelling machine vault

    International Nuclear Information System (INIS)

    Yim, K.; Wong, R.C.; Fluke, R.J.

    1997-01-01

    The GOTHIC code was used to assess the post-accident hydrogen gas mixing patterns in a CANDU reactor containment and demonstrate the acceptability of Ontario Hydro Nuclear's hydrogen mitigation methods. The fuelling machine vault, being a small volume room containing major reactor piping, is the room of most concern with respect to hydrogen concentrations. Detailed three dimensional modelling of the gas mixing patterns in the fuelling machine vault was completed. Results showed that, even without forced air circulation, there is enough dispersion of hydrogen to other parts of containment to preclude the build-up of sensitive mixtures in the vault. For a brief time during the peak period of hydrogen release, hydrogen concentrations rise to close to the lower ignition limit in a small portion of the vault, but these hydrogen-steam-air mixtures are considered acceptable. Natural mixing alone is sufficient to preclude damaging hydrogen burns. (author)

  17. Study of the behaviour of some heavy elements in solvents containing hydrogen fluoride

    International Nuclear Information System (INIS)

    Tarnero, M.

    1967-01-01

    The anhydrous liquid mixtures: dinitrogen tetroxide-hydrogen fluoride and antimony pentafluoride-hydrogen fluoride were studied as solvents for heavy elements interesting nuclear energy: uranium, thorium, zirconium and for some of their compounds. For N 2 O 4 -HF mixtures, electric conductivity measurements and liquid phase infrared spectra were also obtained. Uranium and zirconium tetrafluoride are much more soluble in N 2 O 4 -HF mixtures than in pure hydrogen fluoride. Uranium dissolved in these mixtures is pentavalent. In SbF 5 -HF mixtures, uranium dissolves with hydrogen evolution and becomes trivalent. The solid compound resulting from the dissolution is a fluoro-antimonate: U(SbF 6 ) 3 . (author) [fr

  18. Separating Underdetermined Convolutive Speech Mixtures

    DEFF Research Database (Denmark)

    Pedersen, Michael Syskind; Wang, DeLiang; Larsen, Jan

    2006-01-01

    a method for underdetermined blind source separation of convolutive mixtures. The proposed framework is applicable for separation of instantaneous as well as convolutive speech mixtures. It is possible to iteratively extract each speech signal from the mixture by combining blind source separation...

  19. Mixtures of truncated basis functions

    DEFF Research Database (Denmark)

    Langseth, Helge; Nielsen, Thomas Dyhre; Rumí, Rafael

    2012-01-01

    In this paper we propose a framework, called mixtures of truncated basis functions (MoTBFs), for representing general hybrid Bayesian networks. The proposed framework generalizes both the mixture of truncated exponentials (MTEs) framework and the mixture of polynomials (MoPs) framework. Similar t...

  20. Hydrogen storage materials and method of making by dry homogenation

    Science.gov (United States)

    Jensen, Craig M.; Zidan, Ragaiy A.

    2002-01-01

    Dry homogenized metal hydrides, in particular aluminum hydride compounds, as a material for reversible hydrogen storage is provided. The reversible hydrogen storage material comprises a dry homogenized material having transition metal catalytic sites on a metal aluminum hydride compound, or mixtures of metal aluminum hydride compounds. A method of making such reversible hydrogen storage materials by dry doping is also provided and comprises the steps of dry homogenizing metal hydrides by mechanical mixing, such as be crushing or ball milling a powder, of a metal aluminum hydride with a transition metal catalyst. In another aspect of the invention, a method of powering a vehicle apparatus with the reversible hydrogen storage material is provided.

  1. Journal Of The Korean Hydrogen Energy Society 2

    International Nuclear Information System (INIS)

    2001-11-01

    This book deals with studies such as new ball-milled metal hydride electrode for rechargeable batteries by Noh, Haki; Park, Chung Nyeon, hydrogen absorption by laves phase related BCC solid solution alloys by Etsuo Akiba. The hydrogen absorption kinetics in very thin pd film by Cho, Young Sin; Lee, Jong Suk; Kim, Chang Won. The effect of the ceramic precipitates on the hydrogen solubility in pd alloys by Koh, Je Mann; Lee, Kil Hong; Bada, Seung Nam; Noh, Hak, and AC impedance study of the electrochemical behavior of hydrogen, Oxygen gas mixture at nafion, catalyst electrode interface by Song, S. M and Lee, W. M.

  2. Steam and partial oxidation reforming options for hydrogen production from fossil fuels for PEM fuel cells

    OpenAIRE

    Yousri M.A. Welaya; Mohamed M. El Gohary; Nader R. Ammar

    2012-01-01

    Proton exchange membrane fuel cell (PEM) generates electrical power from air and from hydrogen or hydrogen rich gas mixtures. Therefore, there is an increasing interest in converting current hydrocarbon based marine fuels such as natural gas, gasoline, and diesel into hydrogen rich gases acceptable to the PEM fuel cells on board ships. Using chemical flow sheeting software, the total system efficiency has been calculated. Natural gas appears to be the best fuel for hydrogen rich gas productio...

  3. Prevalence Incidence Mixture Models

    Science.gov (United States)

    The R package and webtool fits Prevalence Incidence Mixture models to left-censored and irregularly interval-censored time to event data that is commonly found in screening cohorts assembled from electronic health records. Absolute and relative risk can be estimated for simple random sampling, and stratified sampling (the two approaches of superpopulation and a finite population are supported for target populations). Non-parametric (absolute risks only), semi-parametric, weakly-parametric (using B-splines), and some fully parametric (such as the logistic-Weibull) models are supported.

  4. Radiation hardenable coating mixture

    International Nuclear Information System (INIS)

    Howard, D.D.

    1977-01-01

    This invention relates to coatings that harden under radiation and to their compositions. Specifically, this invention concerns unsaturated urethane resins polymerisable by addition and to compositions, hardening under the effect of radiation, containing these resins. These resins feature the presence of at least one unsaturated ethylenic terminal group of structure CH 2 =C and containing the product of the reaction of an organic isocyanate compound with at least two isocyanate groups and one polyester polyol with at least two hydroxyl groups, and one unsaturated monomer compound polymerisable by addition having a single active hydrogen group reacting with the isocyanate [fr

  5. Solid oxide fuel cells and hydrogen production

    International Nuclear Information System (INIS)

    Dogan, F.

    2009-01-01

    'Full text': A single-chamber solid oxide fuel cell (SC-SOFC), operating in a mixture of fuel and oxidant gases, provides several advantages over the conventional SOFC such as simplified cell structure (no sealing required). SC-SOFC allows using a variety of fuels without carbon deposition by selecting appropriate electrode materials and cell operating conditions. The operating conditions of single chamber SOFC was studied using hydrocarbon-air gas mixtures for a cell composed of NiO-YSZ / YSZ / LSCF-Ag. The cell performance and catalytic activity of the anode was measured at various gas flow rates. The results showed that the open-circuit voltage and the power density increased as the gas flow rate increased. Relatively high power densities up to 660 mW/cm 2 were obtained in a SC-SOFC using porous YSZ electrolytes instead of dense electrolytes required for operation of a double chamber SOFC. In addition to propane- or methane-air mixtures as a fuel source, the cells were also tested in a double chamber configuration using hydrogen-air mixtures by controlling the hydrogen/air ratio at the cathode and the anode. Simulation of single chamber conditions in double chamber configurations allows distinguishing and better understanding of the electrode reactions in the presence of mixed gases. Recent research efforts; the effect of hydrogen-air mixtures as a fuel source on the performance of anode and cathode materials in single-chamber and double-chamber SOFC configurations,will be presented. The presentation will address a review on hydrogen production by utilizing of reversible SOFC systems. (author)

  6. JUSTIFICATION FOR A LIMIT OF 15 PERCENT HYDROGEN IN A 55-GALLON DRUM

    International Nuclear Information System (INIS)

    MARUSICH, R.M.

    2007-01-01

    The concentration of 15% hydrogen in air in a waste drum is used as the concentration at which the drum remains intact in the case of a deflagration. The following describes what could happen to the drum if 15% hydrogen or more in air were ignited. Table 2 of the Savannah River report WSRC-TR-90-165 ''TRU Drum Hydrogen Explosion Tests'' provides the results of tests performed in 55-gallon drums filled with hydrogen and air mixtures. The hydrogen-air mixtures were ignited by a hot-wire igniter. The results of the tests are shown in Table 1. They concluded that drums can withstand deflagration involving hydrogen concentration up to 15% hydrogen. Testing was performed at Idaho Falls and documented in a letter from RH Beers, Waste Technology Programs Division, EG and G Idaho, to CP Gertz, Radioactive Waste Technology Branch, DOE dated Sept. 29, 1983. In these tests, 55-gallon drums were filled with hydrogen-air mixtures which were ignited. The results in Table 2.2 showed that ignition for drums containing 11% and 14% hydrogen, the drum lid remained on the drum. Ignition in drum with 30% hydrogen resulted in lid loss. It is concluded from the results of these two tests that, for uncorroded drums, a 15% hydrogen in air mixture will not result in loss of drum integrity (i.e., lid remains on, walls remain intact). The drum walls however, may be thinned due to corrosion. The effect of the deflagration on thinner walls is assessed next. Assume a 15% hydrogen in air mixture exists in a drum. The pressure assuming adiabatic isochoric complete combustion (AICC) conditions is 69 psig (using the same deflagration pressure calculation method as in HNF-19492, ''Revised Hydrogen Deflagration Analysis which got 82 psig for 20% hydrogen in air)

  7. Destructive hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Terrisse, H; Dufour, L

    1929-01-21

    Oils of high boiling point, e.g. gas oil, lamp oil, schist oil, brown coal tar etc., are converted into motor benzine by heating them at 200 to 500/sup 0/C under pressure of 5 to 40 kilograms/cm/sup 2/ in the presence of ferrous chloride and gases such as hydrogen, or water gas, the desulfurization of the oils proceeding simultaneously. One kilogram of lamp oil and 100 g. ferrous chloride are heated in an autoclave in the presence of water gas under a pressure of 18 kg/cm/sup 2/ to 380 to 400/sup 0/C. The gaseous products are allowed to escape intermittently and are replaced by fresh water gas. A product distilling between 35 and 270/sup 0/C is obtained.

  8. Separation of gas mixtures

    International Nuclear Information System (INIS)

    1981-01-01

    Apparatus is described for the separation of a gaseous plasma mixture into components in some of which the original concentration of a specific ion has been greatly increased or decreased, comprising: a source for converting the gaseous mixture into a train of plasma packets; an open-ended vessel with a main section and at least one branch section, adapted to enclose along predetermined tracks the original plasma packets in the main section, and the separated plasma components in the branch sections; drive means for generating travelling magnetic waves along the predetermined tracks with the magnetic flux vector of the waves transverse to each of the tracks; and means for maintaining phase coherence between the plasma packets and the magnetic waves at a value needed for accelerating the components of the packets to different velocities and in such different directions that the plasma of each packet is divided into distinctly separate packets in some of which the original concentration of a specific ion has been greatly increased or decreased, and which plasma packets are collected from the branch sections of the vessels. (author)

  9. Ultrasonic Studies of Molecular Interactions in Organic Binary Liquid Mixtures

    Directory of Open Access Journals (Sweden)

    S. Thirumaran

    2010-01-01

    Full Text Available The ultrasonic velocity, density and viscosity have been measured for the mixtures of 1-alkanols such as 1-propanol and 1-butanol with N-N dimethylformamide (DMF at 303 K. The experimental data have been used to calculate the acoustical parameters namely adiabatic compressibility (β, free length (Lf, free volume (Vf and internal pressure (πi. The excess values of the above parameters are also evaluated and discussed in the light of molecular interaction existing in the mixtures. It is obvious that there is a formation of hydrogen bonding between DMF and 1-alkanols. Further, the addition of DMF causes dissociation of hydrogen bonded structure of 1-alkanols. The evaluated excess values confirm that the molecular association is more pronounced in system-II comparing to the system-I.

  10. Hydrogen-Assisted IC Engine Combustion as a Route to Hydrogen Implementation

    Energy Technology Data Exchange (ETDEWEB)

    Andre Boehman; Daniel Haworth

    2008-09-30

    The 'Freedom Car' Initiative announced by the Bush Administration has placed a significant emphasis on development of a hydrogen economy in the United States. While the hydrogen-fueled fuel-cell vehicle that is the focus of the 'Freedom Car' program would rely on electrochemical energy conversion, and despite the large amount of resources being devoted to its objectives, near-term implementation of hydrogen in the transportation sector is not likely to arise from fuel cell cars. Instead, fuel blending and ''hydrogen-assisted'' combustion are more realizable pathways for wide-scale hydrogen utilization within the next ten years. Thus, a large potential avenue for utilization of hydrogen in transportation applications is through blending with natural gas, since there is an existing market for natural-gas vehicles of various classes, and since hydrogen can provide a means of achieving even stricter emissions standards. Another potential avenue is through use of hydrogen to 'assist' diesel combustion to permit alternate combustion strategies that can achieve lower emissions and higher efficiency. This project focused on developing the underlying fundamental information to support technologies that will facilitate the introduction of coal-derived hydrogen into the market. Two paths were envisioned for hydrogen utilization in transportation applications. One is for hydrogen to be mixed with other fuels, specifically natural gas, to enhance performance in existing natural gas-fueled vehicles (e.g., transit buses) and provide a practical and marketable avenue to begin using hydrogen in the field. A second is to use hydrogen to enable alternative combustion modes in existing diesel engines, such as homogeneous charge compression ignition, to permit enhanced efficiency and reduced emissions. Thus, this project on hydrogen-assisted combustion encompassed two major objectives: (1) Optimization of hydrogen-natural gas mixture

  11. Fiscal 1998 research report on International Clean Energy Network using Hydrogen Conversion (WE-NET). Subtask 2. Research on promotion of international cooperation (research on standardization of hydrogen energy technologies); 1998 nendo suiso riyo kokusai clean energy system gijutsu (WE-NET) sub task. 2. Kokusai kyoryoku suishin no tame no chosa kento (suiso energy gijutsu hyojunka ni kansuru chosa kento)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    This report summarizes the fiscal 1998 research result on the basic research on standardization of hydrogen energy technologies, and ISO/TC197. As for the standardization, in relation to the hydrogen station in the WE-NET second phase research, the laws related to handling of gaseous hydrogen, and the basic issues on facility and safe handling were studied. As for ISO/TC197, the following draft standards were examined: Fuel supply system interface for liquid hydrogen vehicles, fuel tank for liquid hydrogen vehicles, container for liquid hydrogen transport, specification of hydrogen fuel, hydrogen fuel supply facility for air ports, gaseous hydrogen and hydrogen mixture fuel system for vehicles, gaseous hydrogen fuel connector for vehicles, gaseous hydrogen fuel tank for vehicles, and basic items for hydrogen system safety. Final examination of the fuel supply system interface for liquid hydrogen vehicles, and the specification of hydrogen fuel was finished, and these are scheduled to be registered for ISO. (NEDO)

  12. The evolution of hydrogen and iodine by the decomposition of ammonium iodide and hydrogen iodide

    International Nuclear Information System (INIS)

    Ishikawa, Hiroshi; Nakane, Masanori; Ishii, Eiichi; Uehara, Itsuki; Miyake, Yoshizo

    1977-01-01

    As a fundamental study on thermochemical production of hydrogen from water, the evolution of hydrogen and iodine from ammonium iodide and hydrogen iodide was investigated. Hydrogen was evolved by the reaction of nickel with ammonium iodide or with hydrogen iodide, and the resulting nickel(II) iodide was decomposed thermally at 600 -- 700 0 C to form nickel. First, the iodination of powdered nickel with ammonium iodide was studied by heating their powder mixture. The maximum yield of hydrogen was obtained at a temperature near 430 0 C. The iodination of powdered nickel with gaseous ammonium iodide or with dry hydrogen iodide gas was also investigated. In this case, coating of nickel particles with a layer of resulting nickel(II) iodide prevented further conversion of nickel and lowered the reaction rate. Such a retardation effect was appreciably lessened by use of carrier. When nickel was supported on such a carrier as ''isolite'', the nickel was converted into nickel(II) iodide easily. In a reaction temperature from 400 to 500 0 C, the rate of reaction between nickel and hydrogen iodide increased slightly with the elevation of the reaction temperature. In the case of ammonium iodide, the reaction rate was higher than that for hydrogen iodide and decreased apparently with the elevation of the reaction temperature, because ammonium iodide decomposed to ammonia and hydrogen iodide. Tests using a fixed bed reactor charged with 8 -- 10 mesh ''isolite''-nickel (30 wt%) were also carried out. The maximum yield of hydrogen was about 80% for ammonium iodide at 430 0 C of reaction temperature and 60% for hydrogen iodide at 500 0 C. (auth.)

  13. Catalyst for hydrogen-amine D exchange

    International Nuclear Information System (INIS)

    Holtslander, W.J.; Johnson, R.E.

    1976-01-01

    A process is claimed for deuterium isotopic enrichment (suitable for use in heavy water production) by amine-hydrogen exchange in which the exchange catalyst comprises a mixture of alkyl amides of two metals selected from the group consisting of the alkali metals. Catalyst mixtures comprising at least one of the alkali amides of lithium and potassium are preferred. At least one of the following benefits are obtained: decreased hydride formation, decreased thermal decomposition of alkyl amide, increased catalyst solubility in the amine phase, and increased exchange efficiency. 11 claims

  14. A windowless frozen hydrogen target system

    International Nuclear Information System (INIS)

    Knowles, P.E.; Beer, G.A.; Beveridge, J.L.

    1995-06-01

    A cryogenic target system has been constructed in which gaseous mixtures of all three hydrogen isotopes have been frozen onto a thin, 65 mm diameter gold foil. The foil is cooled to 3 K while inside a 70 K radiation shield, all of which is mounted in a vacuum system maintained at 10 -9 torr. Stable multi-layer hydrogen targets of known uniformity and thickness have been maintained for required measurement times of up to several days. To date, hundreds of targets have been successfully used in muon-catalyzed fusion experiments at TRIUMF. (author). 12 refs., 6 figs

  15. Research of Deformation of Clay Soil Mixtures Mixtures

    OpenAIRE

    Romas Girkontas; Tadas Tamošiūnas; Andrius Savickas

    2014-01-01

    The aim of this article is to determine clay soils and clay soils mixtures deformations during drying. Experiments consisted from: a) clay and clay mixtures bridges (height ~ 0,30 m, span ~ 1,00 m); b) tiles of clay and clay, sand and straw (height, length, wide); c) cylinders of clay; clay and straw; clay, straw and sand (diameter; height). According to the findings recommendations for clay and clay mixtures drying technology application were presented. During the experiment clay bridge bear...

  16. Mutagenicity of complex mixtures

    International Nuclear Information System (INIS)

    Pelroy, R.A.

    1985-01-01

    The effect of coal-derived complex chemical mixtures on the mutagenicity of 6-aminochrysene (6-AC) was determined with Salmonella typhimurium TA98. Previous results suggested that the mutagenic potency of 6-AC for TA98 in the standard microsomal activation (Ames) assay increased if it was presented to the cells mixed with high-boiling coal liquids (CL) from the solvent refined coal (SRC) process. In this year's work, the apparent mutational synergism of CL and 6-AC was independently verified in a fluctuation bioassay which allowed quantitation of mutational frequencies and cell viability. The results of this assay system were similar to those in the Ames assay. Moreover, the fluctation assay revealed that mutagenesis and cellular toxicity induced by 6-AC were both strongly enhanced if 6-AC was presented to the cells mixed in a high-boiling CL. 4 figures

  17. Method for upgrading diene-containing hydrocarbon mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Kidwell, L.E. Jr.; Holcomb, D.E.

    1984-05-22

    There is disclosed a method for upgrading of hydrocarbon mixtures, so as to reduce their content of gum precursors such as diolefins and pseudo-diolefins, and provide a resulting product mixture suitable for mild hydrogenation, for use as a motor fuel or as a feed stock to an extraction unit. The process comprises obtaining a hydrocarbon mixture containing about 60-90 wt. % of aromatic components, about 3-40 wt. % of dienes and pseudodienes, and monoolefins, and up to about 6 wt. % of relatively unreactive organic compounds, reacting this mixture with elemental sulfur in the approximate weight ratio of about 5-95 wt. % of the hydrocarbon mixture with about 95-5 wt. % of elemental sulfur, the reaction being carried out at a temperature in the range of 100/sup 0/-150/sup 0/ C. for about 10 minutes to 24 hours with good mixing, removing the unreacted materials by distillation and separating a sulfur-hydrocarbon reaction product to provide the upgraded hydrocarbon mixture.

  18. Hydrogen converters

    International Nuclear Information System (INIS)

    Mondino, Angel V.

    2003-01-01

    The National Atomic Energy Commission of Argentina developed a process of 99 Mo production from fission, based on irradiation of uranium aluminide targets with thermal neutrons in the RA-3 reactor of the Ezeiza Atomic Centre. These targets are afterwards dissolved in an alkaline solution, with the consequent liberation of hydrogen as the main gaseous residue. This work deals with the use of a first model of metallic converter and a later prototype of glass converter at laboratory scale, adjusted to the requirements and conditions of the specific redox process. Oxidized copper wires were used, which were reduced to elementary copper at 400 C degrees and then regenerated by oxidation with hot air. Details of the bed structure and the operation conditions are also provided. The equipment required for the assembling in cells is minimal and, taking into account the operation final temperature and the purge with nitrogen, the procedure is totally safe. Finally, the results are extrapolated for the design of a converter to be used in a hot cell. (author)

  19. Robustifying Bayesian nonparametric mixtures for count data.

    Science.gov (United States)

    Canale, Antonio; Prünster, Igor

    2017-03-01

    Our motivating application stems from surveys of natural populations and is characterized by large spatial heterogeneity in the counts, which makes parametric approaches to modeling local animal abundance too restrictive. We adopt a Bayesian nonparametric approach based on mixture models and innovate with respect to popular Dirichlet process mixture of Poisson kernels by increasing the model flexibility at the level both of the kernel and the nonparametric mixing measure. This allows to derive accurate and robust estimates of the distribution of local animal abundance and of the corresponding clusters. The application and a simulation study for different scenarios yield also some general methodological implications. Adding flexibility solely at the level of the mixing measure does not improve inferences, since its impact is severely limited by the rigidity of the Poisson kernel with considerable consequences in terms of bias. However, once a kernel more flexible than the Poisson is chosen, inferences can be robustified by choosing a prior more general than the Dirichlet process. Therefore, to improve the performance of Bayesian nonparametric mixtures for count data one has to enrich the model simultaneously at both levels, the kernel and the mixing measure. © 2016, The International Biometric Society.

  20. Novel Methods of Hydrogen Leak Detection

    International Nuclear Information System (INIS)

    Pushpinder S Puri

    2006-01-01

    For hydrogen to become a consumer fuel for automotive and domestic power generation, safety is paramount. Today's hydrogen systems are built with inherent safety measures and multiple levels of protection. However, human senses, in particular, the sense of smell, is considered the ultimate safeguards against leaks. Since hydrogen is an odorless gas, use of odorants to detect leaks, as is done in case of natural gas, is obvious solution. The odorants required for hydrogen used in fuel cells have a unique requirement which must be met. This is because almost all of the commercial odorants used in gas leak detection contain sulfur which acts as poison for the catalysts used in hydrogen based fuel cells, most specifically for the PEM (polymer electrolyte membrane or proton exchange membrane) fuel cells. A possible solution to this problem is to use non-sulfur containing odorants. Chemical compounds based on mixtures of acrylic acid and nitrogen compounds have been adopted to achieve a sulfur-free odorization of a gas. It is, therefore, desired to have a method and system for hydrogen leak detection using odorant which can incorporate a uniform concentration of odorant in the hydrogen gas, when odorants are mixed in the hydrogen storage or delivery means. It is also desired to develop methods where the odorant is not added to the bulk hydrogen, keeping it free of the odorization additives. A series of novel solutions are proposed which address the issues raised above. These solutions are divided into three categories as follows: 1. Methods incorporating an odorant in the path of hydrogen leak as opposed to adding it to the hydrogen gas. 2. Methods where odorants are generated in-situ by chemical reaction with the leaking hydrogen 3. Methods of dispensing and storing odorants in high pressure hydrogen gas which release odorants to the gas at a uniform and predetermined rates. Use of one or more of the methods described here in conjunction with appropriate engineering

  1. Singlet oxygen reactivity in water-rich solvent mixtures

    Directory of Open Access Journals (Sweden)

    Cristina Sousa

    2008-01-01

    Full Text Available The 3-methylindole (3MI oxygenation sensitized by psoralen (PSO has been investigated in 100%, 20% and 5% O2-saturated water/dioxane (H2O/Dx mixtures. The lowering of the ¹O2* chemical rate when water (k chem∆3MI = 1.4 × 109 M-1 s-1 is replaced by deuterated water (k chem∆3MI = 1.9 × 108 M-1 s-1 suggests that hydrogen abstraction is involved in the rate determining step. A high dependence of the chemical rate constant on water concentration in H2O/Dx mixtures was found showing that water molecules are absolutely essential for the success of the 3MI substrate oxidation by ¹O2* in water-rich solvent mixtures.

  2. Strong and weak hydrogen bonds in drug–DNA complexes

    Indian Academy of Sciences (India)

    The dataset was extracted from the protein data bank (PDB). The analysis was performed with an in-house software, hydrogen bond analysis tool (HBAT). In addition to strong hydrogen bonds such as O−H···O and N−H···O, the ubiquitous presence of weak hydrogen bonds such as C−H···O is implicated in molecular ...

  3. Physisorption of molecular hydrogen on carbon nanotube with vacant defects

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Gang; Shen, Huaze; Wang, Enge; Xu, Limei, E-mail: limei.xu@pku.edu.cn [International Center for Quantum Materials and School of Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, Beijing (China); Tangpanitanon, Jirawat [University of Cambridge, Cambridge, Cambridgeshire CB2 1TP (United Kingdom); Wen, Bo [International Center for Quantum Materials and School of Physics, Peking University, Beijing 100871 (China); Beijing Computational Science Research Center, Heqing Street, Haidian District, Beijing 100084 (China); Xue, Jianming [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China)

    2014-05-28

    Physisorption of molecular hydrogen on single-walled carbon nanotubes (SWCNTs) is important for its engineering applications and hydrogen energy storage. Using molecular dynamics simulation, we study the physisorption of molecular hydrogen on a SWCNT with a vacant defect, focusing on the effect of the vacant defect size and external parameters such as temperature and pressure. We find that hydrogen can be physisorbed inside a SWCNT through a vacant defect when the defect size is above a threshold. By controlling the size of the defects, we are able to extract hydrogen molecules from a gas mixture and store them inside the SWCNT. We also find that external parameters, such as low temperature and high pressure, enhance the physisorption of hydrogen molecules inside the SWCNT. In addition, the storage efficiency can be improved by introducing more defects, i.e., reducing the number of carbon atoms on the SWCNT.

  4. Physisorption of molecular hydrogen on carbon nanotube with vacant defects

    Science.gov (United States)

    Sun, Gang; Tangpanitanon, Jirawat; Shen, Huaze; Wen, Bo; Xue, Jianming; Wang, Enge; Xu, Limei

    2014-05-01

    Physisorption of molecular hydrogen on single-walled carbon nanotubes (SWCNTs) is important for its engineering applications and hydrogen energy storage. Using molecular dynamics simulation, we study the physisorption of molecular hydrogen on a SWCNT with a vacant defect, focusing on the effect of the vacant defect size and external parameters such as temperature and pressure. We find that hydrogen can be physisorbed inside a SWCNT through a vacant defect when the defect size is above a threshold. By controlling the size of the defects, we are able to extract hydrogen molecules from a gas mixture and store them inside the SWCNT. We also find that external parameters, such as low temperature and high pressure, enhance the physisorption of hydrogen molecules inside the SWCNT. In addition, the storage efficiency can be improved by introducing more defects, i.e., reducing the number of carbon atoms on the SWCNT.

  5. Physisorption of molecular hydrogen on carbon nanotube with vacant defects

    International Nuclear Information System (INIS)

    Sun, Gang; Shen, Huaze; Wang, Enge; Xu, Limei; Tangpanitanon, Jirawat; Wen, Bo; Xue, Jianming

    2014-01-01

    Physisorption of molecular hydrogen on single-walled carbon nanotubes (SWCNTs) is important for its engineering applications and hydrogen energy storage. Using molecular dynamics simulation, we study the physisorption of molecular hydrogen on a SWCNT with a vacant defect, focusing on the effect of the vacant defect size and external parameters such as temperature and pressure. We find that hydrogen can be physisorbed inside a SWCNT through a vacant defect when the defect size is above a threshold. By controlling the size of the defects, we are able to extract hydrogen molecules from a gas mixture and store them inside the SWCNT. We also find that external parameters, such as low temperature and high pressure, enhance the physisorption of hydrogen molecules inside the SWCNT. In addition, the storage efficiency can be improved by introducing more defects, i.e., reducing the number of carbon atoms on the SWCNT

  6. CFD simulations for premixed hydrogen-air deflagration from a vented chamber

    International Nuclear Information System (INIS)

    Gera, B.; Ganju, S.

    2015-01-01

    In water cooled power reactors, significant quantities of hydrogen could be produced by a steam-zirconium (fuel clad) reaction following a postulated loss-of-coolant accident (LOCA) along with non-availability of Emergency Core Cooling System (ECCS). Hydrogen in air has the potential for uncontrolled combustion, which has given rise to public concern over the years. The generated hydrogen gets distributed in the different compartment of nuclear reactor containment and may form combustible mixture. Hence, various experimental activities have been performed around the world to investigate severe accident phenomena related to hydrogen combustion. Recently, with the rising concerns for local hydrogen control, numerical calculations for space resolved hydrogen distribution and combustion in the compartment have become an important requirement. Considering all these issues computations have been performed using commercial CFD code CFDACE+ for deflagration of lean dry hydrogen air mixture for a reported experiment. The paper describes the modelling details and main results of the investigation and comparison with experiments

  7. Noncovalent Hydrogen Isotope Effects

    Science.gov (United States)

    Buchachenko, A. L.; Breslavskaya, N. N.

    2018-02-01

    Zero-point energies (ZPE) and isotope effects, induced by intermolecular, noncovalent vibrations, are computed and tested by experimental data. The ZPE differences of H- and D-complexes of water with hydrogen, methane, and water molecules are about 100-300 cal/mol; they result to isotope effects IE of 1.20-1.70. Semi-ionic bonds between metal ions and water ligands in M(H2O) 6 2+ complexes are much stronger; their ZPEs are about 12-14 kcal/mol per molecule and result to IE of 1.9-2.1 at 300 K. Protonated (deuterated) water and biwater exhibit the largest ZPE differences and isotope effects; the latter are 25-28 and 12-13 for water and biwater, respectively. Noncovalent IEs contribute markedly into the experimentally measured effects and explain many anomalous and even magic properties of the effects, such as the dependence of IE on the solvents and on the presence of the third substances, enormously large isotope effects at the mild conditions, the difference between IEs measured in the reactions of individual protiated and deuterated compounds and those measured in their mixture. Noncovalent IEs are not negligible and should be taken into account to make correct and substantiated conclusions on the reaction mechanisms. The kinetic equations are derived for the total isotope effects, which include noncovalent IEs as additive factors.

  8. Method to separate hydrogen fluoride from an uranium hexafluoride-hydrogen fluoride mixture

    International Nuclear Information System (INIS)

    Pfistermeister, M.; Jokar, J.

    1978-01-01

    It is difficult to separate off HF in the purification of UF 6 from additional compounds. According to the invention, it is possible without too greater effort to form the hardly volatile tri-(perfluorobutyl)-ammonium fluoride by adding a perfluorate amine or a derivate of it, and then to separate off the UF 6 from the adduct by simple distillation or sublimation. The adduct can be easily split again with NaOH, so that the amine can be used again without loss. (RW) [de

  9. Evaluation of the toxicity of a mixture of dichlorvos and formaldehyde ...

    African Journals Online (AJOL)

    It was observed that the histopathological examination revealed severe impact on the lungs, mild damage to the liver and certain degree of degeneration in the kidney. The mutagenicity study suggests that the mixture may induce mutation. The adverse health implication of locally compounded or mixture of insecticides ...

  10. Hydrogen formation and control under postulated LMFBR accident conditions

    International Nuclear Information System (INIS)

    Armstrong, G.R.; Wierman, R.W.

    1976-09-01

    The objective of this study is to experimentally investigate the potential for autoignition and combustion of hydrogen-sodium mixtures which may be produced in LMFBR accidents. The purpose and ultimate usefulness of this work is to provide data that will establish the validity and acceptability of mechanisms inherent to the LMFBR that could either prevent or delay the accumulation of hydrogen gas to less than 4 percent (V) in the Reactor Containment Building (RCB) under accident conditions. The results to date indicate that sodium and sodium-hydrogen mixtures such as may be expected during LMFBR postulated accidents will ignite upon entering an air atmosphere and that the hydrogen present will be essentially all consumed until such time that the oxygen concentration is depleted

  11. Hydrogen storage composition and method

    Science.gov (United States)

    Heung, Leung K; Wicks, George G.

    2003-01-01

    A hydrogen storage composition based on a metal hydride dispersed in an aerogel prepared by a sol-gel process. The starting material for the aerogel is an organometallic compound, including the alkoxysilanes, organometals of the form M(OR)x and MOxRy, where R is an alkyl group of the form C.sub.n H.sub.2n+1, M is an oxide-forming metal, n, x, and y are integers, and y is two less than the valence of M. A sol is prepared by combining the starting material, alcohol, water, and an acid. The sol is conditioned to the proper viscosity and a hydride in the form of a fine powder is added. The mixture is polymerized and dried under supercritical conditions. The final product is a composition having a hydride uniformly dispersed throughout an inert, stable and highly porous matrix. It is capable of absorbing up to 30 moles of hydrogen per kilogram at room temperature and pressure, rapidly and reversibly. Hydrogen absorbed by the composition can be readily be recovered by heat or evacuation.

  12. Solubility measurements of hydrogen in 1-butyl-3-methylimidazolium tetrafluoroborate and the effect of carbon dioxide and a selected catalyst on the hydrogen solubility in the ionic liquid

    NARCIS (Netherlands)

    Toussaint, V.A.; Kühne, E.; Shariati - Sarabi, A.; Peters, C.J.

    2013-01-01

    The high pressure phase behavior of a binary mixture containing hydrogen (H-2) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) is studied by measuring bubble-point pressures at different temperatures for three compositions with hydrogen mole fractions of 5, 7.5 and 10 mol%. Since

  13. Electric arc hydrogen heaters

    International Nuclear Information System (INIS)

    Zasypin, I.M.

    2000-01-01

    The experimental data on the electric arc burning in hydrogen are presented. Empirical and semiempirical dependences for calculating the arc characteristics are derived. An engineering method of calculating plasma torches for hydrogen heating is proposed. A model of interaction of a hydrogen arc with a gas flow is outlined. The characteristics of plasma torches for heating hydrogen and hydrogen-bearing gases are described. (author)

  14. Hydrogen considerations in light-water power reactons

    International Nuclear Information System (INIS)

    Keilholtz, G.W.

    1976-02-01

    A critical review of the literature now available on hydrogen considerations in light-water power reactors (LWRs) and a bibliography of that literature are presented. The subject matter includes mechanisms for the generation of hydrogen-oxygen mixtures, a description of the fundamental properties of such mixtures, and their spontaneous ignition in both static and dynamic systems. The limits for hydrogen flammability and flame propagation are examined in terms of the effects of pressure, temperature, and additives; the emphasis is on the effects of steam and water vapor. The containment systems for pressurized-water reactors (PWRs) and boiling-water reactors (BWRs) are compared, and methods to control hydrogen and oxygen under the conditions of both normal operation and postulated accidents are reviewed. It is concluded that hydrogen can be controlled so that serious complications from the production of hydrogen will not occur. The bibliography contains abstracts from the computerized files of the Nuclear Safety Information Center. Key-word, author, and permuted-title indexes are provided. The bibliography includes responses to questions asked by the U. S. Nuclear Regulatory Commission (NRC) which relate to hydrogen, as well as information on normal operations and postulated accidents including generation of hydrogen from core sprays. Other topics included in the ten sections of the bibliography are metal-water reactions, containment atmosphere, radiolytic gas, and recombiners

  15. Selective hydrogenation of maleic anhydride over Pd/Al2O3 ...

    Indian Academy of Sciences (India)

    Keywords. Pd/Al2O3 catalyst; maleic anhydride; selective hydrogenation; succinic anhydride. 1. Introduction ... attracted a significant amount of attention because the majority of its ... added, and the colour of the resulting mixture turned brown.

  16. Hydrogen production from carrot pulp by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana

    NARCIS (Netherlands)

    Vrije, de G.J.; Budde, M.A.W.; Lips, S.J.J.; Bakker, R.R.; Mars, A.E.; Claassen, P.A.M.

    2010-01-01

    Hydrogen was produced from carrot pulp hydrolysate, untreated carrot pulp and (mixtures of) glucose and fructose by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana in pH-controlled bioreactors. Carrot pulp hydrolysate was obtained after enzymatic hydrolysis

  17. Hydrogen desorption reactions of Li-N-H hydrogen storage system: Estimation of activation free energy

    International Nuclear Information System (INIS)

    Matsumoto, Mitsuru; Haga, Tetsuya; Kawai, Yasuaki; Kojima, Yoshitsugu

    2007-01-01

    The dehydrogenation reactions of the mixtures of lithium amide (LiNH 2 ) and lithium hydride (LiH) were studied under an Ar atmosphere by means of temperature programmed desorption (TPD) technique. The dehydrogenation reaction of the LiNH 2 /LiH mixture was accelerated by addition of 1 mol% Ti(III) species (k = 3.1 x 10 -4 s -1 at 493 K), and prolonged ball-milling time (16 h) further enhanced reaction rate (k = 1.1 x 10 -3 s -1 at 493 K). For the hydrogen desorption reaction of Ti(III) doped samples, the activation energies estimated by Kissinger plot (95 kJ mol -1 ) and Arrhenius plot (110 kJ mol -1 ) were in reasonable agreement. The LiNH 2 /LiH mixture without Ti(III) species, exhibited slower hydrogen desorption process and the kinetic traces deviated from single exponential behavior. The results indicated the Ti(III) additives change the hydrogen desorption reaction mechanism of the LiNH 2 /LiH mixture

  18. Complex mixtures biostudies

    International Nuclear Information System (INIS)

    Springer, D.L.

    1987-01-01

    The objective of the project is to identify potential adverse biological activities associated with human exposures to complex organic mixtures (COM) from energy-related industries. Studies to identify the influence of chemical class fractions from a COM on the initiating activity of a known carcinogen, benzo(a)pyrene (BaP), demonstrated that the polycyclic aromatic hydrocarbons (PAH) and nitrogen-containing polycyclic aromatic compound (NPAC) fractions were the most effective inhibitors of initiation. In an effort to determine the contribution of BaP to the initiating activity of the COM, binding of radiolabeled BaP to mouse skin DNA was measured. Results indicated that binding of BaP to DNA decreased in the presence of the COM so that at initiating COM doses, BaP binding was near the limit detection. Addition of unlabeled BaP to the COM at an amount similar to that originally present in the COM did not significantly increase the binding. Studies to determine the rates of disappearance of carcinogenic PAH from the site of application on the skin indicated that half-lives for PAH differed by a factor of about 2. Analytical methods developed to identify PAH from COM which covalently bind to DNA demonstrated that the lower level of detection is approximately 200 picograms. Developmental studies demonstrated that both pregnant rats and mice treated dermally with a high-boiling COM developed fetuses with major malformations including cleft palate, small lungs, edema, and sagittal suture hemorrhages. 3 figures, 5 tables

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

    International Nuclear Information System (INIS)

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

    1994-08-01

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

  20. A model for vented deflagration of hydrogen in a volume

    International Nuclear Information System (INIS)

    Mulpuru, S.R.; Wilkin, G.B.

    1982-02-01

    A simple model was constructed to predict the property transients resulting from the deflagration of a combustible mixture in a sphere or cylinder with venting of the gas mixture to the environment. A computer program VENT, was written to solve the model equation. The model will be particularly useful for studying hydrogen burning effects in loss-of-coolant plus losss of emergency coolant accidents in CANDU reactors

  1. Separation of hydrogen isotopes via single column pressure swing adsorption

    International Nuclear Information System (INIS)

    Wong, Y.W.; Hill, F.B.

    1981-01-01

    Separation of hydrogen isotopes based on kinetic isotope effects was studied. The mixture separated was hydrogen containing a trace of tritium as HT and the hydride was vanadium monohydride. The separation was achieved using the single-column pressure swing process. Stage separation factors are larger and product cuts smaller than for a two-column pressure swing process operated in the same monohydride phase

  2. Spectroscopy of helium hydride and triatomic hydrogen molecules

    International Nuclear Information System (INIS)

    Ketterle, W.

    1986-07-01

    Helium hydride and triatomic hydrogen has been produced by charge exchange between fast mass selected beams of molecular ions and alkali vapor. Using this method, the first discrete spectra of helium hydride were obtained. Fine electronic transitions with resolved rotational structure were observed in the visible and near infrared. Four isotopic mixtures were studied. Furthermore the first lifetime measurement of triatomic hydrogen states were performed and compared to theoretical predictions. (orig.)

  3. Catalytic hydrogenation of carbon monoxide

    International Nuclear Information System (INIS)

    Wayland, B.B.

    1993-12-01

    Focus of this project is on developing new approaches for hydrogenation of carbon monoxide to produce organic oxygenates at mild conditions. The strategies to accomplish CO reduction are based on favorable thermodynamics manifested by rhodium macrocycles for producing a series of intermediates implicated in the catalytic hydrogenation of CO. Metalloformyl complexes from reactions of H 2 and CO, and CO reductive coupling to form metallo α-diketone species provide alternate routes to organic oxygenates that utilize these species as intermediates. Thermodynamic and kinetic-mechanistic studies are used in guiding the design of new metallospecies to improve the thermodynamic and kinetic factors for individual steps in the overall process. Electronic and steric effects associated with the ligand arrays along with the influences of the reaction medium provide the chemical tools for tuning these factors. Non-macrocyclic ligand complexes that emulate the favorable thermodynamic features associated with rhodium macrocycles, but that also manifest improved reaction kinetics are promising candidates for future development

  4. Advanced Hydrogen Transport Membrane for Coal Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Joseph [Praxair, Inc., Tonawanda, NY (United States); Porter, Jason [Colorado School of Mines, Golden, CO (United States); Patki, Neil [Colorado School of Mines, Golden, CO (United States); Kelley, Madison [Colorado School of Mines, Golden, CO (United States); Stanislowski, Josh [Univ. of North Dakota, Grand Forks, ND (United States); Tolbert, Scott [Univ. of North Dakota, Grand Forks, ND (United States); Way, J. Douglas [Colorado School of Mines, Golden, CO (United States); Makuch, David [Praxair, Inc., Tonawanda, NY (United States)

    2015-12-23

    A pilot-scale hydrogen transport membrane (HTM) separator was built that incorporated 98 membranes that were each 24 inches long. This separator used an advanced design to minimize the impact of concentration polarization and separated over 1000 scfh of hydrogen from a hydrogen-nitrogen feed of 5000 scfh that contained 30% hydrogen. This mixture was chosen because it was representative of the hydrogen concentration expected in coal gasification. When tested with an operating gasifier, the hydrogen concentration was lower and contaminants in the syngas adversely impacted membrane performance. All 98 membranes survived the test, but flux was lower than expected. Improved ceramic substrates were produced that have small surface pores to enable membrane production and large pores in the bulk of the substrate to allow high flux. Pd-Au was chosen as the membrane alloy because of its resistance to sulfur contamination and good flux. Processes were developed to produce a large quantity of long membranes for use in the demonstration test.

  5. Component effects in mixture experiments

    International Nuclear Information System (INIS)

    Piepel, G.F.

    1980-01-01

    In a mixture experiment, the response to a mixture of q components is a function of the proportions x 1 , x 2 , ..., x/sub q/ of components in the mixture. Experimental regions for mixture experiments are often defined by constraints on the proportions of the components forming the mixture. The usual (orthogonal direction) definition of a factor effect does not apply because of the dependence imposed by the mixture restriction, /sup q/Σ/sub i=1/ x/sub i/ = 1. A direction within the experimental region in which to compute a mixture component effect is presented and compared to previously suggested directions. This new direction has none of the inadequacies or errors of previous suggestions while having a more meaningful interpretation. The distinction between partial and total effects is made. The uses of partial and total effects (computed using the new direction) in modification and interpretation of mixture response prediction equations are considered. The suggestions of the paper are illustrated in an example from a glass development study in a waste vitrification program. 5 figures, 3 tables

  6. Mixtures of skewed Kalman filters

    KAUST Repository

    Kim, Hyoungmoon; Ryu, Duchwan; Mallick, Bani K.; Genton, Marc G.

    2014-01-01

    Normal state-space models are prevalent, but to increase the applicability of the Kalman filter, we propose mixtures of skewed, and extended skewed, Kalman filters. To do so, the closed skew-normal distribution is extended to a scale mixture class

  7. Easy and flexible mixture distributions

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Mabit, Stefan L.

    2013-01-01

    We propose a method to generate flexible mixture distributions that are useful for estimating models such as the mixed logit model using simulation. The method is easy to implement, yet it can approximate essentially any mixture distribution. We test it with good results in a simulation study...

  8. The use of hydrogen for vehicles

    International Nuclear Information System (INIS)

    Peschka, W.

    1992-01-01

    While the currently utilized or other feasible hydrocarbon fuels release about the same amount of CO 2 during combustion per amount of heat produced, hydrogen represents the only practical, technically feasible, carbon free fuel. The state of the art technology of liquid hydrogen represents a suitable base for large scale demonstration projects now. Additional aims of more intense R and D work relate to internal mixture formation and improved engine roadability as well as utility vehicle application including trucks and buses. With respect to fuel costs there will be an increased demand in developing hydrogen production processes free from CO 2 emissions even from fossil energy sources such as crude oil or natural gas. (orig.) [de

  9. Preparing interesting hydrocarbons by hydrogenation, etc

    Energy Technology Data Exchange (ETDEWEB)

    1938-02-15

    Now, it has been found that gasoline and a combustible oil are produced by destructive hydrogenation of pastes prepared from solid carbonaceous materials and mixtures of middle oils and the mud in question, by regulating the composition of the products removed as vapors in a way that they contain at least the total new heavy oil formed in the course of the destructive hydrogenation and in using as mixing agent for the new raw material the mud proceeding from the operation and middle oil, having withdrawn from this mud all or part of the solid constituents. This destructive hydrogenation is carried out in a converter where a constant level of liquid is maintained, the vapors escaping at the top of the converter and the mud being drawn off at one or more places from the column of liquid undergoing reaction.

  10. Why hydrogen; Pourquoi l'hydrogene?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-02-01

    The energy consumption increase and the associated environmental risks, led to develop new energy sources. The authors present the potentialities of the hydrogen in this context of energy supply safety. They detail the today market and the perspectives, the energy sources for the hydrogen production (fossils, nuclear and renewable), the hydrogen transport, storage, distribution and conversion, the application domains, the associated risks. (A.L.B.)

  11. Hydrogen fuel. Uses

    International Nuclear Information System (INIS)

    Darkrim-Lamari, F.; Malbrunot, P.

    2006-01-01

    Hydrogen is a very energetic fuel which can be used in combustion to generate heat and mechanical energy or which can be used to generate electricity and heat through an electrochemical reaction with oxygen. This article deals with the energy conversion, the availability and safety problems linked with the use of hydrogen, and with the socio-economical consequences of a generalized use of hydrogen: 1 - hydrogen energy conversion: hydrogen engines, aerospace applications, fuel cells (principle, different types, domains of application); 2 - hydrogen energy availability: transport and storage (gas pipelines, liquid hydrogen, adsorbed and absorbed hydrogen in solid materials), service stations; 3 - hazards and safety: flammability, explosibility, storage and transport safety, standards and regulations; 4 - hydrogen economy; 5 - conclusion. (J.S.)

  12. Production method of hydrogen jet plasma process in hydro machinery

    International Nuclear Information System (INIS)

    Amini, F.

    2007-01-01

    The purpose of present paper is to the process of plasma formation in hydro machinery when a hydro turbine operates at various conditions and load rejection. By investigation the power, shock pressure , and impact effects of hydro machinery, it is revealed that energy and hydrogen are generated by the plasma process. The investigation on several turbines of various hydro power plants reveals that cold fusion process in hydro machinery generates hydrogen. The hypothesis concerning the participation of alkaline metals in river water and the atomic nuclei of the runner blade material in the formation of hydrogen are considered. It is possible to assume hydrogen, deuterium, helium, and tritium atoms (based on Dr. Mizuno and Dr. Kanarev theories) that are formed, diffuse into cavitation bubbles. The plasma is generated during the collapse of the bubble; thus, the quantity of burnt hydrogen determine the volume of generating hydrogen and the impact force caused by hydrogen explosion (noise).There are five main notions, which can determine hydrogen and plasma process: (1) turbine power effect, (2) high shock pressure, (3) crack on turbine parts, (4) impacts effects and (4) the lift of rotating parts. The frequency of the excitation lies in a range from 0.786 to 1.095 Hz.In future, it may be possible to design hydro turbines based on the plasma process that generates hydrogen; or there may exist turbines that rotate with a mixture of hydrogen explosion and water energies

  13. Metallic hydrogen: The most powerful rocket fuel yet to exist

    Energy Technology Data Exchange (ETDEWEB)

    Silvera, Isaac F [Lyman Laboratory of Physics, Harvard University, Cambridge MA 02138 (United States); Cole, John W, E-mail: silvera@physics.harvard.ed [NASA MSFC, Huntsville, AL 35801 (United States)

    2010-03-01

    Wigner and Huntington first predicted that pressures of order 25 GPa were required for the transition of solid molecular hydrogen to the atomic metallic phase. Later it was predicted that metallic hydrogen might be a metastable material so that it remains metallic when pressure is released. Experimental pressures achieved on hydrogen have been more than an order of magnitude higher than the predicted transition pressure and yet it remains an insulator. We discuss the applications of metastable metallic hydrogen to rocketry. Metastable metallic hydrogen would be a very light-weight, low volume, powerful rocket propellant. One of the characteristics of a propellant is its specific impulse, I{sub sp}. Liquid (molecular) hydrogen-oxygen used in modern rockets has an Isp of {approx}460s; metallic hydrogen has a theoretical I{sub sp} of 1700s. Detailed analysis shows that such a fuel would allow single-stage rockets to enter into orbit or carry economical payloads to the moon. If pure metallic hydrogen is used as a propellant, the reaction chamber temperature is calculated to be greater than 6000 K, too high for currently known rocket engine materials. By diluting metallic hydrogen with liquid hydrogen or water, the reaction temperature can be reduced, yet there is still a significant performance improvement for the diluted mixture.

  14. Hydrogen energy systems studies

    Energy Technology Data Exchange (ETDEWEB)

    Ogden, J.M.; Kreutz, T.G.; Steinbugler, M. [Princeton Univ., NJ (United States)] [and others

    1996-10-01

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

  15. Numerical analysis on hydrogen stratification and post-inerting of hydrogen risk

    International Nuclear Information System (INIS)

    Peng, Cheng; Tong, Lili; Cao, Xuewu

    2016-01-01

    Highlights: • A three-dimensional computational model was built and the applicability was discussed. • The formation of helium stratification was further studied. • Three influencing factors on the post-inerting of hydrogen risk were analyzed. - Abstract: In the case of severe accidents, the risk of hydrogen explosion threatens the integrity of the nuclear reactor containment. According to nuclear regulations, hydrogen control is required to ensure the safe operation of the nuclear reactor. In this study, the method of Computational Fluid Dynamics (CFD) has been applied to analyze process of hydrogen stratification and the post-inerting of hydrogen risk in the Large-Scale Gas Mixing Facility. A three-dimensional computational model was built and the applicability of different turbulence models was discussed. The result shows that the helium concentration calculated by the standard k–ε turbulence model is closest to the experiment data. Through analyzing the formation of helium stratification at different injection velocities, it is found that when the injection mass flow is constant and the injection velocity of helium increases, the mixture of helium and air is enhanced while there is rarely influence on the formation of helium stratification. In addition, the influences of mass flow rate, injection location and direction and inert gas on the post-inerting of hydrogen risk have been analyzed and the results are as follows: with the increasing of mass flow rate, the mitigation effect of nitrogen on hydrogen risk will be further improved; there is an obvious local difference between the mitigation effects of nitrogen on hydrogen risk in different injection directions and locations; when the inert gas is injected at the same mass flow rate, the mitigation effect of steam on hydrogen risk is better than that of nitrogen. This study can provide technical support for the mitigation of hydrogen risk in the small LWR containment.

  16. Solar based hydrogen production systems

    CERN Document Server

    Dincer, Ibrahim

    2013-01-01

    This book provides a comprehensive analysis of various solar based hydrogen production systems. The book covers first-law (energy based) and second-law (exergy based) efficiencies and provides a comprehensive understanding of their implications. It will help minimize the widespread misuse of efficiencies among students and researchers in energy field by using an intuitive and unified approach for defining efficiencies. The book gives a clear understanding of the sustainability and environmental impact analysis of the above systems. The book will be particularly useful for a clear understanding

  17. Catalytic hydrogenation of carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Wayland, B.B.

    1992-12-01

    This project is focused on developing strategies to accomplish the reduction and hydrogenation of carbon monoxide to produce organic oxygenates at mild conditions. Our approaches to this issue are based on the recognition that rhodium macrocycles have unusually favorable thermodynamic values for producing a series of intermediate implicated in the catalytic hydrogenation of CO. Observations of metalloformyl complexes produced by reactions of H{sub 2} and CO, and reductive coupling of CO to form metallo {alpha}-diketone species have suggested a multiplicity of routes to organic oxygenates that utilize these species as intermediates. Thermodynamic and kinetic-mechanistic studies are used in constructing energy profiles for a variety of potential pathways, and these schemes are used in guiding the design of new metallospecies to improve the thermodynamic and kinetic factors for individual steps in the overall process. Variation of the electronic and steric effects associated with the ligand arrays along with the influences of the reaction medium provide the chemical tools for tuning these factors. Emerging knowledge of the factors that contribute to M-H, M-C and M-O bond enthalpies is directing the search for ligand arrays that will expand the range of metal species that have favorable thermodynamic parameters to produce the primary intermediates for CO hydrogenation. Studies of rhodium complexes are being extended to non-macrocyclic ligand complexes that emulate the favorable thermodynamic features associated with rhodium macrocycles, but that also manifest improved reaction kinetics. Multifunctional catalyst systems designed to couple the ability of rhodium complexes to produce formyl and diketone intermediates with a second catalyst that hydrogenates these imtermediates are promising approaches to accomplish CO hydrogenation at mild conditions.

  18. Hydrogen in metals

    CSIR Research Space (South Africa)

    Carter, TJ

    2001-04-01

    Full Text Available .J. Cartera,*, L.A. Cornishb aAdvanced Engineering & Testing Services, MATTEK, CSIR, Private Bag X28, Auckland Park 2006, South Africa bSchool of Process and Materials Engineering, University of the Witwatersrand, Private Bag 3, P.O. WITS 2050, South Africa... are contrasted, and an unusual case study of hydrogen embrittlement of an alloy steel is presented. 7 2001 Published by Elsevier Science Ltd. Keywords: Hydrogen; Hydrogen-assisted cracking; Hydrogen damage; Hydrogen embrittlement 1. Introduction Hydrogen suC128...

  19. Hydrogen production by water dissociation using ceramic membranes - annual report for FY 2010.

    Energy Technology Data Exchange (ETDEWEB)

    Balachandran, U.; Dorris, S. E.; Emerson, J. E.; Lee, T. H.; Lu, Y.; Park, C. Y.; Picciolo, J. J. (Energy Systems)

    2011-03-14

    The objective of this project is to develop dense ceramic membranes that can produce hydrogen via coal/coal gas-assisted water dissociation without using an external power supply or circuitry. This project grew from an effort to develop a dense ceramic membrane for separating hydrogen from gas mixtures such as those generated during coal gasification, methane partial oxidation, and water-gas shift reactions. That effort led to the development of various cermet (i.e., ceramic/metal composite) membranes that enable hydrogen production by two methods. In one method, a hydrogen transport membrane (HTM) selectively removes hydrogen from a gas mixture by transporting it through either a mixed protonic/electronic conductor or a hydrogen transport metal. In the other method, an oxygen transport membrane (OTM) generates hydrogen mixed with steam by removing oxygen that is generated through water splitting. This project focuses on the development of OTMs that efficiently produce hydrogen via the dissociation of water. Supercritical boilers offer very high-pressure steam that can be decomposed to provide pure hydrogen using OTMs. Oxygen resulting from the dissociation of steam can be used for coal gasification, enriched combustion, or synthesis gas production. Hydrogen and sequestration-ready CO{sub 2} can be produced from coal and steam by using the membrane being developed in this project. Although hydrogen can also be generated by high-temperature steam electrolysis, producing hydrogen by water splitting with a mixed-conducting membrane requires no electric power or electrical circuitry.

  20. A general mixture theory. I. Mixtures of spherical molecules

    Science.gov (United States)

    Hamad, Esam Z.

    1996-08-01

    We present a new general theory for obtaining mixture properties from the pure species equations of state. The theory addresses the composition and the unlike interactions dependence of mixture equation of state. The density expansion of the mixture equation gives the exact composition dependence of all virial coefficients. The theory introduces multiple-index parameters that can be calculated from binary unlike interaction parameters. In this first part of the work, details are presented for the first and second levels of approximations for spherical molecules. The second order model is simple and very accurate. It predicts the compressibility factor of additive hard spheres within simulation uncertainty (equimolar with size ratio of three). For nonadditive hard spheres, comparison with compressibility factor simulation data over a wide range of density, composition, and nonadditivity parameter, gave an average error of 2%. For mixtures of Lennard-Jones molecules, the model predictions are better than the Weeks-Chandler-Anderson perturbation theory.

  1. Simulation of startup period of hydrogen isotope separation distillation column

    International Nuclear Information System (INIS)

    Sazonov, A.B.; Kagramanov, Z.G.; Magomedbekov, Eh.P.

    2003-01-01

    Kinetic procedure for the mathematical simulation of start-up regime of rectification columns for molecular hydrogen isotope separation was developed. Nonstationary state (start-up period) of separating column for rectification of multi-component mixture was calculated. Full information on equilibrium and kinetic physicochemical properties of components in separating mixtures was used for the calculations. Profile of concentration of components by height of column in task moment of time was calculated by means of differential equilibriums of nonstationary mass transfer. Calculated results of nonstationary state of column by the 2 m height, 30 mm diameter during separation of the mixture: 5 % protium, 70 % deuterium, 25 % tritium were illustrated [ru

  2. Latent hazard related to a hydrogen liquefaction installation

    International Nuclear Information System (INIS)

    Spoendlin, R.

    1961-01-01

    In this note, the author reports an attempt of analysis of hazards which could be related to a hydrogen liquefaction installation in order to identify the most appropriate safety measures. In order to do so, experiments have been performed on electrostatic charges born by solid crystals in liquid hydrogen, and explosion tests have been performed on a mixture of solid oxygen and liquid hydrogen. Moreover, the author tried to analyse accidents which occurred in this field by performing a survey among scientists working in laboratories in different countries

  3. Device to remove hydrogen isotopes from a gas phase

    International Nuclear Information System (INIS)

    Morlock, G.; Wiesemes, J.; Bachner, D.

    1977-01-01

    The device described here guarantees the selective removal of hydrogen isotopes from gas phases in order to prevent the occurence of explosive H 2 gas mixtures, or to separate off radioactive tritium in nuclear plants from the gas phase. It consists of a closed container whose walls are selectively penetrable by hydrogen isotopes. It is simultaneously filled compactly and presssure-resistant with a metal bulk (e.g. powder, sponges or the like of titanium or other hydrogen isotope binding metal). Walling and bulk are maintained at suitable working temperatures by means of a system according to the Peltier effect. The whole thing is safeguarded by protective walling. (RB) [de

  4. Study of cycle-by-cycle variations of a spark ignition engine fueled with natural gas-hydrogen blends

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jinhua; Chen, Hao; Liu, Bing; Huang, Zuohua [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2008-09-15

    Cycle-by-cycle variations of a spark ignition engine fueled with natural gas-hydrogen blends with hydrogen volumetric fraction of 0%, 12%, 23%, 30% and 40% were studied. The effect of hydrogen addition on cycle-by-cycle variations of the natural gas engine was analyzed. The results showed that the peak cylinder pressure, the maximum rate of pressure rise and the indicated mean effective pressure increased and their corresponding cycle-by-cycle variations decreased with the increase of hydrogen fraction at lean mixture operation. The interdependency between the combustion parameters and the corresponding crank angle tended to be strongly correlated with the increase of hydrogen fraction under lean mixture operation. Coefficient of variation of the indicated mean effective pressure gave a low level and is slightly influenced by hydrogen addition under the stoichiometric and relatively rich mixture operation while it decreased remarkably with the increase of hydrogen fraction under the lean mixture operation. The excessive air ratio at CoV{sub imep} = 10% extended to the leaner mixture side with the increase of hydrogen fraction and this indicated that the engine lean operating limit could be extended with hydrogen addition. (author)

  5. Fuel Cell and Hydrogen Technologies Program | Hydrogen and Fuel Cells |

    Science.gov (United States)

    NREL Fuel Cell and Hydrogen Technologies Program Fuel Cell and Hydrogen Technologies Program Through its Fuel Cell and Hydrogen Technologies Program, NREL researches, develops, analyzes, and validates fuel cell and hydrogen production, delivery, and storage technologies for transportation

  6. Dynamics of hydrogen in hydrogenated amorphous silicon

    Indian Academy of Sciences (India)

    is mobile and can easily move through the material). Hydrogen diffuses ... The determination of the relationship of light-enhanced hydrogen motion to ... term is negligible, and using the thermodynamic relation given below f(c) = kBT .... device-applications problematic but the normal state can be recovered by a thermal an-.

  7. Hydrogen peroxide and ferulic acid-mediated oxidative cross-linking ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-12-15

    Dec 15, 2009 ... G250 in a 4.5:4.5:1 (v/v) mixture of deionized water, methanol and glacial acetic ... mixture of 1:1:8 (v/v) methanol, glacial acetic acid and deionized water until the ..... Cross-linking of tyrosine-containing peptides by hydrogen.

  8. A Mixed Ligand Approach for the Asymmetric Hydrogenation of 2-Substituted Pyridinium Salts

    NARCIS (Netherlands)

    Renom-Carrasco, Marc; Gajewski, Piotr; Pignataro, Luca; de Vries, Johannes G.; Piarulli, Umberto; Gennari, Cesare; Lefort, Laurent

    2016-01-01

    Herein we describe a new methodology for the asymmetric hydrogenation (AH) of 2-substituted pyridinium salts. An iridium catalyst based on a mixture of a chiral monodentate phosphoramidite and an achiral phosphine was shown to hydrogenate N-benzyl-2-arylpyiridinium bromides to the corresponding

  9. Palladium-catalyzed hydrodehalogenation of 1,2,4,5-tetrachlorobenzene in water-ethanol mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Wee, Hun-Young [Department of Civil Engineering, Texas A and M University, College Station, TX 77843 (United States); Cunningham, Jeffrey A. [Department of Civil and Environmental Engineering, University of South Florida, Tampa, FL 33620 (United States)], E-mail: cunning@eng.usf.edu

    2008-06-30

    Palladium-catalyzed hydrodehalogenation (HDH) was applied for destroying 1,2,4,5-tetrachlorobenzene (TeCB) in mixtures of water and ethanol. This investigation was performed as a critical step in the development of a new technology for clean-up of soil contaminated by halogenated hydrophobic organic contaminants. The main goals of the investigation were to demonstrate the feasibility of the technology, to determine the effect of the solvent composition (water:ethanol ratio), and to develop a model for the kinetics of the dehalogenation process. All experiments were conducted in a batch reactor at ambient temperature under mild hydrogen pressure. The experimental results are all consistent with a Langmuir-Hinshelwood model for heterogeneous catalysis. Major findings that can be interpreted within the Langmuir-Hinshelwood framework include: (1) the rate of hydrodehalogenation depends strongly on the solvent composition, increasing as the water fraction of the solvent increases; (2) the HDH rate increases as the catalyst concentration in the reactor increases; (3) when enough catalyst is present, the HDH reaction appears to follow first-order kinetics, but the kinetics appear to be zero-order at low catalyst concentrations. TeCB is converted rapidly and quantitatively to benzene, with only trace concentrations of 1,2,4-trichlorobenzene appearing as a reactive intermediate. The results obtained here have important implications for the further development of the proposed soil remediation technology, and may also be important for the treatment of other hazardous waste streams.

  10. Palladium-catalyzed hydrodehalogenation of 1,2,4,5-tetrachlorobenzene in water-ethanol mixtures

    International Nuclear Information System (INIS)

    Wee, Hun-Young; Cunningham, Jeffrey A.

    2008-01-01

    Palladium-catalyzed hydrodehalogenation (HDH) was applied for destroying 1,2,4,5-tetrachlorobenzene (TeCB) in mixtures of water and ethanol. This investigation was performed as a critical step in the development of a new technology for clean-up of soil contaminated by halogenated hydrophobic organic contaminants. The main goals of the investigation were to demonstrate the feasibility of the technology, to determine the effect of the solvent composition (water:ethanol ratio), and to develop a model for the kinetics of the dehalogenation process. All experiments were conducted in a batch reactor at ambient temperature under mild hydrogen pressure. The experimental results are all consistent with a Langmuir-Hinshelwood model for heterogeneous catalysis. Major findings that can be interpreted within the Langmuir-Hinshelwood framework include: (1) the rate of hydrodehalogenation depends strongly on the solvent composition, increasing as the water fraction of the solvent increases; (2) the HDH rate increases as the catalyst concentration in the reactor increases; (3) when enough catalyst is present, the HDH reaction appears to follow first-order kinetics, but the kinetics appear to be zero-order at low catalyst concentrations. TeCB is converted rapidly and quantitatively to benzene, with only trace concentrations of 1,2,4-trichlorobenzene appearing as a reactive intermediate. The results obtained here have important implications for the further development of the proposed soil remediation technology, and may also be important for the treatment of other hazardous waste streams

  11. Handbook of hydrogen energy

    CERN Document Server

    Sherif, SA; Stefanakos, EK; Steinfeld, Aldo

    2014-01-01

    ""This book provides an excellent overview of the hydrogen economy and a thorough and comprehensive presentation of hydrogen production and storage methods.""-Scott E. Grasman, Rochester Institute of Technology, New York, USA

  12. Hydrogen production by Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Chaudhuri Surabhi

    2005-12-01

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

  13. Center for Hydrogen Storage.

    Science.gov (United States)

    2013-06-01

    The main goals of this project were to (1) Establish a Center for Hydrogen Storage Research at Delaware State University for the preparation and characterization of selected complex metal hydrides and the determination their suitability for hydrogen ...

  14. First measurements of dtμ-cycle characteristics in liquid H/D/T mixture

    International Nuclear Information System (INIS)

    Averin, Yu.P.; Balin, D.V.; Bom, V.R.

    1998-01-01

    The muon catalyzed fusion in dense triple mixture of hydrogen isotopes has been investigated for the first time. The experimental method is based on the registration of neutrons from dtμ fusions by a full absorption detectors in 4π geometry. The measurements have been performed in H/D/T mixture at T = 22 K and φ ≅ 1.1 LHD at four sets of isotope concentrations. The basic parameters of dtμ cycle (neutron yield, cycling rate and total sticking) in H/D/T mixtures are presented and discussed

  15. Inflammable gax mixtures in biogas facilities; Entzuendbare Gasgemische in Biogasanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Volkmar; Pahl, Robert [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany). Fachbereich 2.1 ' Gase, Gasanlagen'

    2013-09-15

    The number of the biogas facilities in Germany has strongly increased with the extension of regenerative energy. In the facilities by decomposition of organic matter inflammable biogas is obtained, which strongly fluctuates in its composition. The main components of biogas are methane and carbon dioxide, but also depending on the process-level water vapor, nitrogen,oxygen, and impurities, which may partly be toxic. In addition it is begun to work up biogas in larger facilities in order to feed it directly in the natural-gas network. In the development are currently also coupled biogas and electrolysis facilities. By means of the electrolysis of water also surpluses of electrical energy from wind and solar facilities can be processed to hydrogen (power-to-gas technology). In order to make reliable data for the explosion protection in the handling with the gas mixtures present in the facilities available, the BAM has in the last years measured explosion ranges of mixtures of methane, hydrogen, carbon dioxide, water vapor, air, and oxygen in accordance with the standard EN 1839 and made available as key data. By means of these data the explosion ability of the gas mixtures in biogas facilities can be reliably estimated. On this base corresponding explosion-protection actions can be taken.

  16. Hydrogen behavior at a subcomparment in the containment building

    Energy Technology Data Exchange (ETDEWEB)

    Lee, U. J.; Park, G. C. [Seoul National University, Seoul (Korea, Republic of)

    1997-12-31

    For hydrogen management in severe accidents with degraded nuclear core of PWR`s, several experiments have been performed in the SNU hydrogen mixing facility. The objectives are understanding the extent of hydrogen mixing and analyzing the effects of factors which dominate uniform or non-uniform mixing at compartments in the containment building. The facility represents on a 1/11th linearly scaled model of the YGN unit 3 and 4, hydrogen was simulated by helium. Because there are the gaps between safety injection tank and compartment layers in the containment, the test facility was constructed in three dimensional mode for analyzing of mixture behaviour through the gaps. >From the experimental results we could conclude that overall hydrogen concentration distributed uniformly in the free volume of the test compartment, but fluctuated in the gaps. This paper is focused on experimental result from several experiments. 5 refs., 4 figs. (Author)

  17. New Transition metal assisted complex borohydrides for hydrogen storage

    International Nuclear Information System (INIS)

    Sesha Srinivasan; Elias Lee Stefanakos; Yogi Goswami

    2006-01-01

    High capacity hydrogen storage systems are indeed essential for the on-board vehicular application that leads to the pollution free environment. Apart from the various hydrogen storage systems explored in the past, complex hydrides involving light weight alkali/alkaline metals exhibits promising hydrogenation/ dehydrogenation characteristics. New transition metal assisted complex borohydrides [Zn(BH 4 ) 2 ] have been successfully synthesized by an inexpensive mechano-chemical process. These complex hydrides possesses gravimetric hydrogen storage capacity of ∼8.4 wt.% at around 120 C. We have determined the volumetric hydrogen absorption and desorption of these materials for a number of cycles. Another complex borohydride mixture LiBH 4 /MgH 2 catalyzed with ZnCl 2 has been synthesized and characterized using various analytical techniques. (authors)

  18. Management of Leaks in Hydrogen Production, Delivery, and Storage Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rawls, G

    2006-04-27

    A systematic approach to manage hydrogen leakage from components is presented. Methods to evaluate the quantity of hydrogen leakage and permeation from a system are provided by calculation and testing sensitivities. The following technology components of a leak management program are described: (1) Methods to evaluate hydrogen gas loss through leaks; (2) Methods to calculate opening areas of crack like defects; (3) Permeation of hydrogen through metallic piping; (4) Code requirements for acceptable flammability limits; (5) Methods to detect flammable gas; (6) Requirements for adequate ventilation in the vicinity of the hydrogen system; (7) Methods to calculate dilution air requirements for flammable gas mixtures; and (8) Concepts for reduced leakage component selection and permeation barriers.

  19. Hydrogen behavior at a subcomparment in the containment building

    Energy Technology Data Exchange (ETDEWEB)

    Lee, U J; Park, G C [Seoul National University, Seoul (Korea, Republic of)

    1998-12-31

    For hydrogen management in severe accidents with degraded nuclear core of PWR`s, several experiments have been performed in the SNU hydrogen mixing facility. The objectives are understanding the extent of hydrogen mixing and analyzing the effects of factors which dominate uniform or non-uniform mixing at compartments in the containment building. The facility represents on a 1/11th linearly scaled model of the YGN unit 3 and 4, hydrogen was simulated by helium. Because there are the gaps between safety injection tank and compartment layers in the containment, the test facility was constructed in three dimensional mode for analyzing of mixture behaviour through the gaps. >From the experimental results we could conclude that overall hydrogen concentration distributed uniformly in the free volume of the test compartment, but fluctuated in the gaps. This paper is focused on experimental result from several experiments. 5 refs., 4 figs. (Author)

  20. Hydrogen Adsorption in Zeolite Studied with Sievert and Thermogravimetric Methods

    International Nuclear Information System (INIS)

    Lesnicenoks, P; Sivars, A; Grinberga, L; Kleperis, J

    2012-01-01

    Natural clinoptilolite (mixture from clinoptilolite, quartz and muscovite) is activated with palladium and tested for hydrogen adsorption capability at temperatures RT - 200°C. Thermogravimetric and volumetric methods showed that zeolite activated with palladium (1.25%wt) shows markedly high hydrogen adsorption capacity - up to 3 wt%. Lower amount of adsorbed hydrogen (∼1.5 wt%) was found for raw zeolite and activated with higher amount of palladium sample. Hypothesis is proposed that the heating of zeolite in argon atmosphere forms and activates the pore structure in zeolite material, where hydrogen encapsulation (trapping) is believed to occur when cooling down to room temperature. An effect of catalyst (Pd) on hydrogen sorption capability is explained by spillover phenomena were less-porous fractions of natural clinoptilolite sample (quartz and muscovite) are involved.