Glass Bubbles Insulation for Liquid Hydrogen Storage Tanks

Science.gov (United States)

Sass, J. P.; SaintCyr, W. W.; Barrett, T. M.; Baumgartner, R. G.; Lott, J. W.; Fesmire, J. E.

2009-01-01

A full-scale field application of glass bubbles insulation has been demonstrated in a 218,000 L liquid hydrogen storage tank. This work is the evolution of extensive materials testing, laboratory scale testing, and system studies leading to the use of glass bubbles insulation as a cost efficient and high performance alternative in cryogenic storage tanks of any size. The tank utilized is part of a rocket propulsion test complex at the NASA Stennis Space Center and is a 1960's vintage spherical double wall tank with an evacuated annulus. The original perlite that was removed from the annulus was in pristine condition and showed no signs of deterioration or compaction. Test results show a significant reduction in liquid hydrogen boiloff when compared to recent baseline data prior to removal of the perlite insulation. The data also validates the previous laboratory scale testing (1000 L) and full-scale numerical modeling (3,200,000 L) of boiloff in spherical cryogenic storage tanks. The performance of the tank will continue to be monitored during operation of the tank over the coming years. KEYWORDS: Glass bubble, perlite, insulation, liquid hydrogen, storage tank.

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.

Process, including PSA and membrane separation, for separating hydrogen from hydrocarbons

Science.gov (United States)

Baker, Richard W.; Lokhandwala, Kaaeid A.; He, Zhenjie; Pinnau, Ingo

2001-01-01

An improved process for separating hydrogen from hydrocarbons. The process includes a pressure swing adsorption step, a compression/cooling step and a membrane separation step. The membrane step relies on achieving a methane/hydrogen selectivity of at least about 2.5 under the conditions of the process.

Flexible, Heat-Resistant, and Flame-Retardant Glass Fiber Nonwoven/Glass Platelet Composite Separator for Lithium-Ion Batteries

Directory of Open Access Journals (Sweden)

Ulrich Schadeck

2018-04-01

Full Text Available A new type of high-temperature stable and self-supporting composite separator for lithium-ion batteries was developed consisting of custom-made ultrathin micrometer-sized glass platelets embedded in a glass fiber nonwoven together with a water-based sodium alginate binder. The physical and electrochemical properties were investigated and compared to commercial polymer-based separators. Full-cell configuration cycling tests at different current rates were performed using graphite and lithium iron phosphate as electrode materials. The glass separator was high-temperature tested and showed a stability up to at least 600 °C without significant shrinking. Furthermore, it showed an exceptional wettability for non-aqueous electrolytes. The electrochemical performance was excellent compared to commercially available polymer-based separators. The results clearly show that glass platelets integrated into a glass fiber nonwoven performs remarkably well as a separator material in lithium-ion batteries and show high-temperature stability.

Hydrogen isotope separation by cryogenic distillation method

International Nuclear Information System (INIS)

Hayakawa, Nobuo; Mitsui, Jin

1987-01-01

Hydrogen isotope separation in fusion fuel cycle and tritium recovery from heavy water reactor are very important, and therefore the early establishment of these separation techniques are desired. The cryogenic distillation method in particular is promising for the separation of hydrogen isotope and the recovery of high concentrated tritium. The studies of hydrogen isotope separation by cryogenic distillation method have been carried out by using the experimental apparatus made for the first time in Japan. The separation of three components (H 2 -HD-D 2 ) under total reflux conditions was got by using the packing tower of 500 mm height. It was confirmed that the Height Equivalent Theoretical Plate (HETP) was 20 - 30 mm for the vapor's line velocity of 20 - 80 mm/s. (author)

Laser photochemical separation of hydrogen isotopes

International Nuclear Information System (INIS)

Fowler, M.C.

1979-01-01

A method of separating isotopes of hydrogen utilizing isotopically selective photodissociation of organic acid is disclosed. Specifically acetic or formic acid containing compounds of deuterated nd hydrogenated acid is irradiated by radiation having a wavelength in the infrared spectrum between 9.2 to 10.8 microns to produce deuterium hydroxide and deuterium hydride respectively. Maintaining the acid at an elevated temperature significantly improves the yield of isotope separation

Effect of MoO3 addition on phase separation in borosilicate glasses

International Nuclear Information System (INIS)

Wakabayashi, Hajimu; Yamanaka, Hiroshi; Terai, Ryohei; Fukumoto, Shinji.

1987-01-01

The effect of MoO 3 addition on the phase separation of sodium borosilicate glasses has been studied by electron microscopic observation and electrical conductivity measurement. With increasing MoO 3 addition, the immiscibility temperatures rose, the growth rate of phase separation increased, and the immiscibility region in the Na 2 O-B 2 O 3 -SiO 2 system extended. When MoO 3 more than 5 mol% was added to the glasses, two stages of phase separation appeared ; one is metastable immiscibility, which takes place below the liquidus temperature, and the other is stable immiscibility, occurring above the liquidus temperature. The present experiment confirmed that the conductivity measurement of molten glasses is usefull to detect phase separation in the glasses, giving some suggestions for preventing the separation of molybdates in nuclear waste glasses and also for controlling the micro-pore sizes of porous glasses. (author)

Separation of hydrogen isotope by hydrogen-water exchange

International Nuclear Information System (INIS)

Isomura, Shohei; Kaetsu, Hayato; Nakane, Ryohei

1979-01-01

The deuterium exchange reaction between gaseous hydrogen and liquid water is studied by use of three kinds of trickle bed exchange columns packed with hydrophobic catalysts supporting platinum. All columns have the effective lengths of 30 cm. They are 17 mm, 30 mm, and 95 mm in diameters, respectively. The separation experiments are carried out by the once-through methods. The separation efficiencies of the columns are evaluated by the parameters such as the height equivalent to a theoretical plate (H. E. T. P.) and the mass transfer co-efficient. It is found that the operating condition of the exchange column is optimum when the superficial hydrogen flow velocity is 0.3 m/sec. (author)

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.

Novel, Ceramic Membrane System For Hydrogen Separation

Energy Technology Data Exchange (ETDEWEB)

Elangovan, S.

2012-12-31

Separation of hydrogen from coal gas represents one of the most promising ways to produce alternative sources of fuel. Ceramatec, teamed with CoorsTek and Sandia National Laboratories has developed materials technology for a pressure driven, high temperature proton-electron mixed conducting membrane system to remove hydrogen from the syngas. This system separates high purity hydrogen and isolates high pressure CO{sub 2} as the retentate, which is amenable to low cost capture and transport to storage sites. The team demonstrated a highly efficient, pressure-driven hydrogen separation membrane to generate high purity hydrogen from syngas using a novel ceramic-ceramic composite membrane. Recognizing the benefits and limitations of present membrane systems, the all-ceramic system has been developed to address the key technical challenges related to materials performance under actual operating conditions, while retaining the advantages of thermal and process compatibility offered by the ceramic membranes. The feasibility of the concept has already been demonstrated at Ceramatec. This project developed advanced materials composition for potential integration with water gas shift rectors to maximize the hydrogenproduction.

Fabrication of All Glass Bifurcation Microfluidic Chip for Blood Plasma Separation

Directory of Open Access Journals (Sweden)

Hyungjun Jang

2017-02-01

Full Text Available An all-glass bifurcation microfluidic chip for blood plasma separation was fabricated by a cost-effective glass molding process using an amorphous carbon (AC mold, which in turn was fabricated by the carbonization of a replicated furan precursor. To compensate for the shrinkage during AC mold fabrication, an enlarged photoresist pattern master was designed, and an AC mold with a dimensional error of 2.9% was achieved; the dimensional error of the master pattern was 1.6%. In the glass molding process, a glass microchannel plate with negligible shape errors (~1.5% compared to AC mold was replicated. Finally, an all-glass bifurcation microfluidic chip was realized by micro drilling and thermal fusion bonding processes. A separation efficiency of 74% was obtained using the fabricated all-glass bifurcation microfluidic chip.

Micro-Raman spectroscopy studies of the phase separation mechanisms of transition-metal phosphate glasses

International Nuclear Information System (INIS)

Mazali, Italo Odone; Alves, Oswaldo Luiz; Gimenez, Iara de Fatima

2009-01-01

Glass-ceramics are prepared by controlled separation of crystal phases in glasses, leading to uniform and dense grain structures. On the other hand, chemical leaching of soluble crystal phases yields porous glass-ceramics with important applications. Here, glass/ceramic interfaces of niobo-, vanado- and titano-phosphate glasses were studied by micro-Raman spectroscopy, whose spatial resolution revealed the multiphase structures. Phase-separation mechanisms were also determined by this technique, revealing that interface composition remained unchanged as the crystallization front advanced for niobo- and vanadophosphate glasses (interface-controlled crystallization). For titanophosphate glasses, phase composition changed continuously with time up to the equilibrium composition, indicating a spinodal-type phase separation. (author)

Separation of Hydrogen Isotopes by Palladium Alloy Membranes Separator

International Nuclear Information System (INIS)

Jiangfeng, S.; Deli, L.; Yifu, X.; Congxian, L.; Zhiyong, H.

2007-01-01

Full text of publication follows: Separation of hydrogen isotope with palladium alloy membranes is one of the promising methods for hydrogen isotope separation. It has several advantages, such as high separation efficiency, smaller tritium inventory, simple separation device, ect. Limited by the manufacture of membrane and cost of gas transportation pump, this method is still at the stage of conceptual study. The relationship between separation factors and temperatures, feed gas components, split ratios have not been researched in detail, and the calculated results of cascade separation have not been validated with experimental data. In this thesis, a palladium alloy membrane separator was designed to further study its separation performance between H 2 and D 2 . The separation factor of the single stage was affected by the temperature, the feed gas component, the split ratio and the gas flow rate, etc. The experimental results showed that the H 2 -D 2 separation factor decreased with the increasing of temperature. On the temperature from 573 K to 773 K, when the feed rate was 5 L/min, the separation factor of 66.2%H 2 - 33.8%D 2 decreased from 2.09 to 1.85 when the split ratio was 0.1 and from 1.74 to 1.52 when the split ratio was 0.2.The separation factor also decreased with the increasing of split ratio. At 573 K and the feed rate of 5 L/min, the separation factor of 15.0%H 2 and 85.0%D 2 decreased from 2.43 to 1.35 with the increasing of split ratio from 0.050 to 0.534,and for 66.2%H 2 -33.8%D 2 , the separation factor decreased from 2.87 to 1.30 with the increasing of split ratio from 0.050 to 0.688. When the separation factor was the biggest, the flow rate of feed gas was in a perfect value. To gain a best separation performance, perfect flow rate, lower temperature and reflux ratio should be chosen. (authors)

Phase separation of cesium from lead borosilicate glass by heat treatment under a reducing atmosphere

Energy Technology Data Exchange (ETDEWEB)

Xu, Zhanglian; Okada, Takashi, E-mail: t-okada@u-fukui.ac.jp; Nishimura, Fumihiro; Yonezawa, Susumu

2016-11-05

Highlights: • Cesium was phase separated from lead borosilicate glass under a reductive atmosphere. • The phase separation occurred on the glass surface that was in contact with the gas. • The leachability of cesium was enhanced by the phase separation. • The degree of such enhancement varied depending on the heat treatment conditions. - Abstract: A phase-separation technique for removing sodium from glass using a heat-treatment method under a reducing atmosphere was previously developed for sodium recovery from waste glass. In this study, this technique was applied to cesium-containing lead borosilicate glass to concentrate the cesium in phase-separated sodium-rich materials for efficient cesium extraction. The theoretical phase-separation temperature of the sodium-rich phase was simulated by thermodynamic equilibrium calculations and was predicted to occur below 700 °C for lead borosilicate glass. Experimentally, a simulated lead borosilicate glass was melted at 1000 °C and subsequently annealed below 700 °C under a CO-containing reducing atmosphere. The phase separation of cesium was found to occur with sodium enrichment on the glass surface that was in contact with the gas phase, promoting cesium extraction from the treated glass using water. The cesium extraction efficiency was affected by the surface area of the treated glass that was in contact with water, and under the examined conditions, the cesium extraction efficiency was up to 66%. Phase separation using reductive heat treatment, combined with a water leaching technique, is suggested to be effective for extracting cesium incorporated in borosilicate glass waste.

Melting, solidification, remelting, and separation of glass and metal

International Nuclear Information System (INIS)

Ebadian, M.A.; Xin, R.C.; Liu, Y.Z.

1998-01-01

Several high-temperature vitrification technologies have been developed for the treatment of a wide range of mixed waste types in both the low-level waste and transuranic (TRU) mixed waste categories currently in storage at DOE sites throughout the nation. The products of these processes are an oxide slag phase and a reduced metal phase. The metal phase has the potential to be recycled within the DOE Complex. Enhanced slag/metal separation methods are needed to support these processes. This research project involves an experimental investigation of the melting, solidification, remelting, and separation of glass and metal and the development of an efficient separation technology. The ultimate goal of this project is to find an efficient way to separate the slag phase from the metal phase in the molten state. This two-year project commenced in October 1995 (FY96). In the first fiscal year, the following tasks were accomplished: (1) A literature review and an assessment of the baseline glass and metal separation technologies were performed. The results indicated that the baseline technology yields a high percentage of glass in the metal phase, requiring further separation. (2) The main melting and solidification system setup was established. A number of melting and solidification tests were conducted. (3) Temperature distribution, solidification patterns, and flow field in the molten metal pool were simulated numerically for the solidification processes of molten aluminum and iron steel. (4) Initial designs of the laboratory-scale DCS and CS technologies were also completed. The principal demonstration separation units were constructed. (5) An application for a patent for an innovative liquid-liquid separation technology was submitted and is pending

Laser-induced separation of hydrogen isotopes in the liquid phase

International Nuclear Information System (INIS)

Beattie, W.; Freund, S.; Holland, R.; Maier, W.

1980-01-01

A process for separating hydrogen isotopes which comprises (A) forming a liquid phase of hydrogen-bearing feedstock compound at a temperature at which the spectral features of the feedstock compound are narrow enough or the absorption edges sharp enough to permit spectral features corresponding to the different hydrogen isotopes to be separated to be distinguished, (B) irradiating the liquid phase at said temperature with monochromatic radiation of a first wavelength which selectively or at least preferentially excites those molecules of said feedstock compound containing a first hydrogen isotope, and (C) subjecting the excited molecules to physical or chemical processes or a combination thereof whereby said first hydrogen isotope contained in said excited molecules is separated from other hydrogen isotopes contained in the unexcited molecules in said liquid phase

Fragility and cooperativity concepts in hydrogen-bonded organic glasses

International Nuclear Information System (INIS)

Delpouve, N.; Vuillequez, A.; Saiter, A.; Youssef, B.; Saiter, J.M.

2012-01-01

Molecular dynamics at the glass transition of three lactose/oil glassy systems have been investigated according to the cooperativity and fragility approaches. From Donth's approach, the cooperativity length is estimated by modulated temperature calorimetric measurements. Results reveal that modification of the disaccharide by oil leads to increase the disorder degree in the lactose, the size of the cooperative domains and the fragility index. These particular hydrogen-bonded organic glasses follow the general tendency observed on organic and inorganic polymers: the higher the cooperativity length, the higher the value of the fragility index at T g .

Photoelectrochemical water splitting in separate oxygen and hydrogen cells

Science.gov (United States)

Landman, Avigail; Dotan, Hen; Shter, Gennady E.; Wullenkord, Michael; Houaijia, Anis; Maljusch, Artjom; Grader, Gideon S.; Rothschild, Avner

2017-06-01

Solar water splitting provides a promising path for sustainable hydrogen production and solar energy storage. One of the greatest challenges towards large-scale utilization of this technology is reducing the hydrogen production cost. The conventional electrolyser architecture, where hydrogen and oxygen are co-produced in the same cell, gives rise to critical challenges in photoelectrochemical water splitting cells that directly convert solar energy and water to hydrogen. Here we overcome these challenges by separating the hydrogen and oxygen cells. The ion exchange in our cells is mediated by auxiliary electrodes, and the cells are connected to each other only by metal wires, enabling centralized hydrogen production. We demonstrate hydrogen generation in separate cells with solar-to-hydrogen conversion efficiency of 7.5%, which can readily surpass 10% using standard commercial components. A basic cost comparison shows that our approach is competitive with conventional photoelectrochemical systems, enabling safe and potentially affordable solar hydrogen production.

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)

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

Fragility and cooperativity concepts in hydrogen-bonded organic glasses

Energy Technology Data Exchange (ETDEWEB)

Delpouve, N., E-mail: delpouve.nicolas@gmail.com [AMME-LECAP EA 4528 International Laboratory, University of Rouen, Avenue de l' Universite BP 12, 76801 Saint Etienne du Rouvray (France); Vuillequez, A.; Saiter, A.; Youssef, B.; Saiter, J.M. [AMME-LECAP EA 4528 International Laboratory, University of Rouen, Avenue de l' Universite BP 12, 76801 Saint Etienne du Rouvray (France)

2012-09-01

Molecular dynamics at the glass transition of three lactose/oil glassy systems have been investigated according to the cooperativity and fragility approaches. From Donth's approach, the cooperativity length is estimated by modulated temperature calorimetric measurements. Results reveal that modification of the disaccharide by oil leads to increase the disorder degree in the lactose, the size of the cooperative domains and the fragility index. These particular hydrogen-bonded organic glasses follow the general tendency observed on organic and inorganic polymers: the higher the cooperativity length, the higher the value of the fragility index at T{sub g}.

Near-infrared analysis of hydrogen-bonding in glass- and rubber-state amorphous saccharide solids.

Science.gov (United States)

Izutsu, Ken-ichi; Hiyama, Yukio; Yomota, Chikako; Kawanishi, Toru

2009-01-01

Near-infrared (NIR) spectroscopic analysis of noncrystalline polyols and saccharides (e.g., glycerol, sorbitol, maltitol, glucose, sucrose, maltose) was performed at different temperatures (30-80 degrees C) to elucidate the effect of glass transition on molecular interaction. Transmission NIR spectra (4,000-12,000 cm(-1)) of the liquids and cooled-melt amorphous solids showed broad absorption bands that indicate random configuration of molecules. Heating of the samples decreased an intermolecular hydrogen-bonding OH vibration band intensity (6,200-6,500 cm(-1)) with a concomitant increase in a free and intramolecular hydrogen-bonding OH group band (6,600-7,100 cm(-1)). Large reduction of the intermolecular hydrogen-bonding band intensity at temperatures above the glass transition (T(g)) of the individual solids should explain the higher molecular mobility and lower viscosity in the rubber state. Mixing of the polyols with a high T(g) saccharide (maltose) or an inorganic salt (sodium tetraborate) shifted both the glass transition and the inflection point of the hydrogen-bonding band intensity to higher temperatures. The implications of these results for pharmaceutical formulation design and process monitoring (PAT) are discussed.

Premixing hydrogen burners for surface refinement of glass; Vormischende Wasserstoffbrenner zur Oberflaechenbearbeitung von Glas

Energy Technology Data Exchange (ETDEWEB)

Goerisch, Matthias [Linde AG, Linde Gas Deutschland, Nuernberg (Germany)

2013-02-15

As a result, inter alia, of unceasing globalisation, European glass producers in practically all sectors - flat glass, container glass, crystal glass and special glasses - are faced with ever tougher competition from Asia. In the 2012 to 2015 period and beyond, the principal focuses in the manufacture of glass products will again be on reducing overall production costs and increasing process efficiency wherever possible, on greater productivity and on enhanced product (surface) quality. To meet these challenges in the field of surface refinement and flame polishing of glass products as efficiently as possible, Linde AG/Linde Gases Division has developed premixing Hydropox {sup registered} burner technology for hydrogen/oxygen fuels. (orig.)

Analysis of hydrogen separation methods in low pressure industrial processes

International Nuclear Information System (INIS)

Milidoni, M.; Somoza, J.; Borzone, E.M.; Blanco, M.V.; Cestau, D.; Baruj, A.; Meyer, G.

2012-01-01

In this work we present strategies for removing part of the hydrogen contained in a tank of 500 1 at a total pressure of 95 kPa. Hydrogen is mixed with other gases in a relation 95:5. The gas is generated as an end product during the production of radioisotopes. Main impurities are N 2 , humidity and activated gases. Two separation methods are proposed: one of them based on the use of a commercial Pd/Cu membrane, while the other involves the use of materials capable of forming metal hydrides (HFM). Characterization of hydrogen separation properties using a Pd/Cu membrane from pure H 2 and H 2 /Ar mixture were performed in the laboratory. We present simulations of a device containing HFM of the LaNi 5 -xSnx (0.x.0,5), using the properties of reaction with hydrogen measured in our laboratory. The performance of the different options was evaluated. Results were compared using as evaluation criteria the value of the pressure in the tank after 3 h of separation process and the time needed to separate the same amount of hydrogen generated during a batch of the process (author)

Hydrogen isotope separation for fusion power applications

Energy Technology Data Exchange (ETDEWEB)

Smith, R., E-mail: robert.smith@ccfe.ac.uk [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Whittaker, D.A.J.; Butler, B.; Hollingsworth, A.; Lawless, R.E.; Lefebvre, X.; Medley, S.A.; Parracho, A.I.; Wakeling, B. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

2015-10-05

Highlights: • Summary of the tritium plant, the Active Gas Handling System (AGHS), at JET. • Review of the Water Detritiation System (WDS) under construction. • Design of the new Material Detritiation Facility (MDF). • Review of problems in fusion related to metal/hydrogen system. - Abstract: The invited talk given at MH2014 in Salford ranged over many issues associated with hydrogen isotope separation, fusion machines and the hydrogen/metal systems found in the Joint European Torus (JET) machine located near Oxford. As this sort of talk does not lend itself well to a paper below I have attempted to highlight some of the more pertinent information. After a description of the Active Gas Handling System (AGHS) a brief summary of isotope separation systems is described followed by descriptions of three major projects currently being undertaken by the Tritium Engineering and Science Group (TESG), the upgrade to the Analytical Systems (AN-GC) at the AGH, the construction of a Water Detritiation System (WDS) and a Material Detritiation Facility (MDF). Finally, a review of some of the challenges facing fusion with respect to metal/hydrogen systems is presented.

Effect of heat treatment duration on phase separation of sodium borosilicate glass, containing copper

International Nuclear Information System (INIS)

Shejnina, T.G.; Gutner, S.Kh.; Anan'in, N.I.

1989-01-01

The effect of heat treatment duration on phase separation of sodium borosilicate (SBS) glass, containing copper is studied. It is stated that phase separation close to equilibrium one is attained under 12 hours of heat treatment of SBS glass containing copper

Hydrogen absorption by thin Pd/Nb films deposited on glass

International Nuclear Information System (INIS)

Reisfeld, G.; Jisrawi, N.M.; Ruckman, M.W.; Strongin, M.

1996-01-01

Hydrogen absorption by 200 endash 2000-A-thick Pd-capped Nb films, between 5 and 110 degree C, was studied by simultaneous four-probe resistivity and volumetric measurements. The resistivity as a function of hydrogen concentration was measured while charging the films with hydrogen, and was used to compute the change in hydrogen concentration in the film, during the reaction with oxygen. For the thinnest films (200 A thick), the hydrogen charging and discharging curves indicate that a first-order gas-liquid-like phase transition with a T c of 70 endash 75 degree C takes place. The H-Nb phase diagram for the 200-A film looks like the H/bulk Nb α-α' phase diagram which has a higher T c (173 degree C). We attribute the substantial modifications of the film close-quote s phase diagram to the clamping of the Nb film at its interfaces with glass and Pd and to the nanostructure of the films. copyright 1996 The American Physical Society

Nano-phase separation and structural ordering in silica-rich mixed network former glasses.

Science.gov (United States)

Liu, Hao; Youngman, Randall E; Kapoor, Saurabh; Jensen, Lars R; Smedskjaer, Morten M; Yue, Yuanzheng

2018-06-13

We investigate the structure, phase separation, glass transition, and crystallization in a mixed network former glass series, i.e., B2O3-Al2O3-SiO2-P2O5 glasses with varying SiO2/B2O3 molar ratio. All the studied glasses exhibit two separate glassy phases: droplet phase (G1) with the size of 50-100 nm and matrix phase (G2), corresponding to a lower calorimetric glass transition temperature (Tg1) and a higher one (Tg2), respectively. Both Tg values decrease linearly with the substitution of B2O3 for SiO2, but the magnitude of the decrease is larger for Tg1. Based on nuclear magnetic resonance and Raman spectroscopy results, we infer that the G1 phase is rich in boroxol rings, while the G2 phase mainly involves the B-O-Si network. Both phases contain BPO4- and AlPO4-like units. Ordered domains occur in G2 upon isothermal and dynamic heating, driven by the structural heterogeneity in the as-prepared glasses. The structural ordering lowers the activation energy of crystal growth, thus promoting partial crystallization of G2. These findings are useful for understanding glass formation and phase separation in mixed network former oxide systems, and for tailoring their properties.

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)

ALTERNATIVE MATERIALS TO PD MEMBRANES FOR HYDROGEN PURIFICATION

Energy Technology Data Exchange (ETDEWEB)

Korinko, P; T. Adams

2008-09-12

Development of advanced hydrogen separation membranes in support of hydrogen production processes such as coal gasification and as front end gas purifiers for fuel cell based system is paramount to the successful implementation of a national hydrogen economy. Current generation metallic hydrogen separation membranes are based on Pd-alloys. Although the technology has proven successful, at issue is the high cost of palladium. Evaluation of non-noble metal based dense metallic separation membranes is currently receiving national and international attention. The focal point of the reported work was to evaluate two different classes of materials for potential replacement of conventional Pd-alloy purification/diffuser membranes. Crystalline V-Ni-Ti and Amorphous Fe- and Co-based metallic glass alloys have been evaluated using gaseous hydrogen permeation testing techniques.

A model for the stabilization of atomic hydrogen centers in borate glasses

International Nuclear Information System (INIS)

Pontuschka, W.M.; Isotani, S.; Furtado, W.W.; Piccini, A.; Rabbani, S.R.

1989-04-01

A model describing the trapping site of the interstitial atomic hydrogen (H sup(0) sub(i) in borate glasses x-irradiated at 77 K is proposed. The hydrogen atom is stabilized at the centers of oxygen polygons belonging to B-O ring structures in the glass network by van der Waals forces. The previously reported H sup(0) sub(i) isothermal decay experimental data are discussed in the light of this microscopic model. A coupled differential equation system describing the possible reactions was numerically solved by means of Runge-Kutta's method. The parameter best fit was found by trial and error. The untrapping parameter provided an activation energy of 0.7 x 10 sup(-19) J, in good agreement with the calculated results for dispersion interactions between the stabilized atomic hydrogen and the neighbouring oxygen atoms at the vertices of hexagonal and heptagonal structures. The retrapping and recombination parameters were found to be correlated to (T sup1/2) - T sup(1/2) sub(0)) where t sub(0)=179 K is a cutoff temperature for the kinetics process. (author)

Investigation into periodic process of hydrogen isotope separation by counterflow method in the hydrogen-palladium system

International Nuclear Information System (INIS)

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

1999-01-01

The key diagram and results of the investigation into working conditions of the pilot plant for hydrogen isotope separation embodying the concept of continuous counterflow separation in the hydrogen-palladium system are shown. The counterflow of phases in the plant is attained under the motion of palladium solid hydride phase relative to stationary blocks of flow rotation. The column separator is defined as section type one. The plant performs in periodic regime with accumulating vessels for light and heavy components of the separated mixture. Maximum concentration of the separated tritium ranged up to ∼ 96 % in the experiments of the deuterium-tritium separation. Minimum concentration of the residual tritium in the mixture ranged up to ∼ 0.1 %. The plant provides to reprocessing 4.5 moles of the gas a day [ru

Test plan: Effects of phase separation on waste loading for high level waste glasses

International Nuclear Information System (INIS)

Jantzen, C.M.

2000-01-01

As part of the Tanks Focus Area's (TFA) effort to increase waste loading for high-level waste (HLW) vitrification at various facilities in the Department of Energy (DOE) complex, the occurrence of phase separation in waste glasses spanning the Savannah River Site (SRS) and Idaho National Engineering and Environmental Laboratory (INEEL) composition ranges were studied during FY99. The type, extent, and impact of phase separation on glass durability for a series of HLW glasses, e.g., SRS-type and INEEL-type, were examined

Parameter study on Japanese proposal of ITER hydrogen isotope separation system

International Nuclear Information System (INIS)

Yoshida, Hiroshi; Enoeda, Mikio; Tanaka, Shigeru; Ohokawa, Yoshinao; Ohara, Atsushi; Nagakura, Masaaki; Naito, Taisei; Nagashima, Kazuhiro.

1991-01-01

As part of Japanese design contribution in the ITER activity, conceptual design of an entire ITER tritium system and their safety analysis have been carried out through the three-year period since 1988. The tritium system includes the following subsystems; - Fuelling (gas puffing and pellet injection) subsystem, - Torus vacuum pumping subsystem, - Plasma exhaust gas purification subsystem, - Hydrogen isotope separation subsystem, - NBI gas processing subsystem, - Blanket tritium recovery subsystem, - Tritiated water processing subsystem, - Tritium safety subsystem. Hydrogen isotope separation system is a key subsystem in the ITER tritium system because it is connected to all above subsystems. This report describes an analytical study on the Japanese concept of hydrogen isotope separation system. (author)

Cascades for hydrogen isotope separation using metal hydrides

International Nuclear Information System (INIS)

Hill, F.B.; Grzetic, V.

1982-01-01

Designs are presented for continuous countercurrent hydrogen isotope separation cascades based on the use of metal hydrides. The cascades are made up of pressure swing adsorption (PSA) or temperature swing adsorption (TSA) stages. The designs were evolved from consideration of previously conducted studies of the separation performance of four types of PSA and TSA processes

Cascades for hydrogen isotope separation using metal hydrides

Energy Technology Data Exchange (ETDEWEB)

Hill, F B; Grzetic, V [Brookhaven National Lab., Upton, NY (USA)

1983-02-01

Designs are presented for continuous countercurrent hydrogen isotope separation cascades based on the use of metal hydrides. The cascades are made up of pressure swing adsorption (PSA) or temperature swing adsorption (TSA) stages. The designs were evolved from consideration of previously conducted studies of the separation performance of four types of PSA and TSA processes.

Combined electrolysis catalytic exchange (CECE) process for hydrogen isotope separation

International Nuclear Information System (INIS)

Hammerli, M.; Stevens, W.H.; Butler, J.P.

1978-01-01

Hydrogen isotopes can be separated efficiently by a process which combines an electrolysis cell with a trickle bed column packed with a hydrophobic platinum catalyst. The column effects isotopic exchange between countercurrent streams of electrolytic hydrogen and liquid water while the electrolysis cell contributes to isotope separation by virtue of the kinetic isotope effect inherent in the hydrogen evolution reaction. The main features of the CECE process for heavy water production are presented as well as a discussion of the inherent positive synergistic effects, and other advantages and disadvantages of the process. Several potential applications of the process in the nuclear power industry are discussed. 3 figures, 2 tables

Hydrogen permeation through metallic foils

International Nuclear Information System (INIS)

Bernardi, M.I.B.; Rodrigues, J.A.

1987-01-01

The process of electrolytic permeation of hydrogen through metallic foils is studied. A double electrolytic cell, in glass, in which the two compartments of reaction are separated by a metallic foil to be studied, was built. As direct result, the hydrogen diffusion coefficient in the metal is obtained. The hydrogen diffusion coefficients in the palladium and, in austenitic stainless steels 304 and 304 L, used in the Angra-1 reactor, were obtained. Samples of stainless steels with and without welding, were used. (Author) [pt

Improved estimates of separation distances to prevent unacceptable damage to nuclear power plant structures from hydrogen detonation for gaseous hydrogen storage. Technical report

International Nuclear Information System (INIS)

1994-05-01

This report provides new estimates of separation distances for nuclear power plant gaseous hydrogen storage facilities. Unacceptable damage to plant structures from hydrogen detonations will be prevented by having hydrogen storage facilities meet separation distance criteria recommended in this report. The revised standoff distances are based on improved calculations on hydrogen gas cloud detonations and structural analysis of reinforced concrete structures. Also, the results presented in this study do not depend upon equivalencing a hydrogen detonation to an equivalent TNT detonation. The static and stagnation pressures, wave velocity, and the shock wave impulse delivered to wall surfaces were computed for several different size hydrogen explosions. Separation distance equations were developed and were used to compute the minimum separation distance for six different wall cases and for seven detonating volumes (from 1.59 to 79.67 lbm of hydrogen). These improved calculation results were compared to previous calculations. The ratio between the separation distance predicted in this report versus that predicted for hydrogen detonation in previous calculations varies from 0 to approximately 4. Thus, the separation distances results from the previous calculations can be either overconservative or unconservative depending upon the set of hydrogen detonation parameters that are used. Consequently, it is concluded that the hydrogen-to-TNT detonation equivalency utilized in previous calculations should no longer be used

Recycling of waste automotive laminated glass and valorization of polyvinyl butyral through mechanochemical separation

International Nuclear Information System (INIS)

Swain, Basudev; Ryang Park, Jae; Yoon Shin, Dong; Park, Kyung-Soo; Hwan Hong, Myung; Gi Lee, Chan

2015-01-01

Due to strong binding, optical clarity, adhesion to many surfaces, toughness and flexibility polyvinyl butyral (PVB) resin films are commonly used in the automotive and architectural application as a protective interlayer in the laminated glass. Worldwide million tons of PVB waste generated from end-of-life automotive associated with various environmental issues. Stringent environmental directive, higher land cost eliminates land filling option, needs a study, we have developed a mechanochemical separation process to separate PVB resins from glass and characterized the separated PVB through various techniques, i.e., scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR). Commercial nonionic surfactants D201 used for the mechanochemical separation purpose. Through parameter optimization following conditions are considered to be the optimum condition; 30 vol% D201, stirring speed of 400 rpm, 35 °C temperature, operation time 1 h, and dilute D201 volume to waste automotive laminated glass weight ratio of ≈25. The technology developed in our laboratory is sustainable, environmentally friendly, techno-economical feasible process, capable of mass production (recycling). - Highlights: • Waste automotive laminated glass and polyvinyl butyral mechanochemically separated. • An economical total recovery and environment-friendly process has been developed. • It is a global problem rather than regional environmental issue has been addressed. • Without using hazardous chemical wastes are being converted to a wealth.

The Laboratory for Laser Energetics’ Hydrogen Isotope Separation System

Energy Technology Data Exchange (ETDEWEB)

Shmayda, W.T., E-mail: wshm@lle.rochester.edu; Wittman, M.D.; Earley, R.F.; Reid, J.L.; Redden, N.P.

2016-11-01

The University of Rochester’s Laboratory for Laser Energetics has commissioned a hydrogen Isotope Separation System (ISS). The ISS uses two columns—palladium on kieselguhr and molecular sieve—that act in a complementary manner to separate the hydrogen species by mass. The 4-sL per day throughput system is compact and has no moving parts. The columns and the attendant gas storage and handling subsystems are housed in a 0.8 -m{sup 3} glovebox. The glovebox uses a helium cover gas that is continuously processed to extract oxygen and water vapor that permeates through the glovebox gloves and any tritium that is released while attaching or detaching vessels to add feedstock to or drawing product from the system. The isotopic separation process is automated and does not require manual intervention. A total of 315 TBq of tritium was extracted from 23.6 sL of hydrogen with tritium purities reaching 99.5%. Deuterium was the sole residual component in the processed gas. Raffinate contained 0.2 TBq of activity was captured for reprocessing. The total emission from the system to the environment was 0.4 GBq over three weeks.

Novel Concept For Hydrogen And CO2 Separation

International Nuclear Information System (INIS)

Adam Campen; Kanchan Mondal; Tomasz Wiltowski; Tomasz Wiltowski

2006-01-01

The process was developed for the separation of hydrogen from coal gasification based syngas components for end uses such as clean energy production. The process is flexible such that it can be used within the gasifier to separate hydrogen or as a separate unit process, depending on the requirements of the process design. The basic idea of the research was to design and apply solids to be used in a fixed bed reactor that will increase the hydrogen yield as well as capture greenhouse gases in its matrix through reaction. The end product envisioned in this process is pure hydrogen. The spent solids were then regenerated thermo neutrally while releasing sequestration-ready carbon dioxide. The research involved the validation of the process along with the evaluation of the process parameters to maximize the hydrogen content in the product stream. The effect of sulfur (present as H 2 S) in the product stream on the process efficiency was also evaluated. Most importantly, the solids were designed such that they have the maximum selectivity to the beneficial reactions while maintaining their structure and activity through the reaction-regeneration cycles. Iron (created by reduction of hematite with syngas) was selected as the Boudouard catalyst and CaO was selected as the carbon dioxide removal material. Thermogravimetric (TG) and Temperature Programmed Reduction (TPR) Analysis were utilized to evaluate the reaction rate parameters, and capacity for CO 2 . Specially synthesized CaO (wherein the surface properties were modified) was found to provide better capacity and reaction rates as compared to commercially available CaO. In addition, these specially synthesized CaO-based sorbent showed lower deactivation over multiple cycles. Experiments were also performed with different compositions of syngas to identify the optimal conditions for pure H 2 production. Finally, simultaneous coal gasification and hydrogen enrichment experiments were conducted. It was found that for a

PROCESS AND APPARATUS FOR SEPARATING INDIVIDUAL PANES FROM A LAMINATED GLASS SHEET

OpenAIRE

Kübler, R.; Rist, T.; Hoetger, B.

2011-01-01

The invention relates to a process for separating at least one individual pane of predefined size and edge form from a laminated glass sheet, which has at least two laminated glass sheet panes which are arranged one above another in adjacent form and between which there is arranged a plastic film, which permanently bonds the laminated glass sheet panes to one another, wherein - a laser track channel which at least weakens the plastic structure of the plastic film is laid into the plastic film...

Nanoporous materials for hydrogen storage and H2/D2 isotope separation

International Nuclear Information System (INIS)

Oh, Hyunchul

2014-01-01

This thesis presents a study of hydrogen adsorption properties at RT with noble metal doped porous materials and an efficient separation of hydrogen isotopes with nanoporous materials. Most analysis is performed via thermal desorption spectra (TDS) and Sieverts-type apparatus. The result and discussion is presented in two parts; Chapter 4 focuses on metal doped nanoporous materials for hydrogen storage. Cryogenic hydrogen storage by physisorption on porous materials has the advantage of high reversibility and fast refuelling times with low heat evolution at modest pressures. At room temperature, however, the physisorption mechanism is not abEle to achieve enough capacity for practical application due to the weak van der Waals interaction, i.e., low isosteric heats for hydrogen sorption. Recently, the ''spillover'' effect has been proposed by R. Yang et al. to enhance the room temperature hydrogen storage capacity. However, the mechanism of this storage enhancement by decoration of noble metal particles inside high surface area supports is not yet fully understood and still under debate. In this chapter, noble metal (Pt / Pd) doped nanoporous materials (i.e. porous carbon, COFs) have been investigated for room temperature hydrogen storage. Their textural properties and hydrogen storage capacity are characterized by various analytic techniques (e.g. SEM, HRTEM, XRD, BET, ICP-OES, Thermal desorption spectra, Sievert's apparatus and Raman spectroscopy). Firstly, Pt-doped and un-doped templated carbons possessing almost identical textural properties were successfully synthesized via a single step wet impregnation method. This enables the study of Pt catalytic activities and hydrogen adsorption kinetics on porous carbons at ambient temperature by TDS after H 2 /D 2 gas exposure and PCT measurement, respectively. While the H 2 adsorption kinetics in the microporous structure is enhanced by Pt catalytic activities (spillover), only a small enhancement of the hydrogen

Study on atmospheric hydrogen enrichment by cryopump method and isotope separation by gas chromatography

International Nuclear Information System (INIS)

Taniyama, Yuki; Momoshima, Noriyuki

2001-01-01

To obtain the information of source of atmospheric hydrogen tritium an analysis of tritium isotopes is thought to be effective. So an atmospheric hydrogen enrichment apparatus and a cryogenic gas chromatographic column were made. Experiments were carried out to study the performance of cryopump to enrich atmospheric hydrogen and the column to separate hydrogen isotopes that obtained by cryopump method. The cryopump was able to process about 1000 1 atmosphere and the column was able to separate hydrogen isotopes with good resolution. (author)

Separation of hydrogen isotopes for tritium waste removal

International Nuclear Information System (INIS)

Wilkes, W.R.

1975-01-01

A distillation cascade for separating hydrogen isotopes was simulated by means of a multicomponent, multistage computer code. A hypothetical test mixture containing equal atomic fractions of protium, deuterium and tritium, equilibrated to high temperature molecular concentrations was used as feed. The results show that a two-column cascade can be used to separate the protium from the tritium. Deuterium appears both in the protium and the tritium product streams. (auth)

Determination of the deuterium separation factor between ammonia and hydrogen; Determination du facteur de separation du deuterium entre l'ammoniac et l'hydrogene

Energy Technology Data Exchange (ETDEWEB)

Ravoire, J; Grandcollot, P; Dirian, G; Montel, J

1963-07-01

The separation factors between hydrogen and gaseous ammonia ({alpha}{sub g}) and between hydrogen and liquid ammonia ({alpha}{sub l}) have been determined by experimental measurements and by calculations from spectrographic data, using existing data concerning the separation factor between liquid ammonia and gaseous ammonia ({alpha}{sub v}). The values of {alpha}{sub v}, {alpha}{sub g} and {alpha}{sub l} are given in a table for a temperature range between - 70 deg C and + 40 deg C. The following equations have been established: log {alpha}{sub g} = 218 {+-} 1/T - 0.1841, from - 70 deg. C to + 40 deg. C. log {alpha}{sub g} = 216 {+-} 1/T + Q, valid at every temperature, Q being known as a function of temperature. log {alpha}{sub l} = 233 {+-} 1/T - 0.2283, from - 70 deg. C a -25 deg. C. (authors) [French] Les facteurs de separation hydrogene-ammoniac gazeux ({alpha}{sub g}) et hydrogene-ammoniac liquide ({alpha}{sub l}) ont ete determines a l'aide de mesures experimentales et de calculs a partir des donnees spectrographiques, en utilisant les donnees existantes relatives au facteur de separation ammoniac liquide-ammoniac gazeux ({alpha}{sub v}) Les valeurs de {alpha}{sub v}, {alpha}{sub g}, et {alpha}{sub l} sont donnees sous forme de tableau pour des temperatures allant de - 70 deg. C a + 40 deg. C. Les relations suivantes ont ete etablies: log {alpha}{sub g} = 218 {+-} 1/T - 0.1841, valable de - 70 deg. C a + 40 deg. C. log {alpha}{sub g} = 216 {+-} 1/T + Q, valable a toute temperature, Q etant connu en fonction de la temperature. log {alpha}{sub l} = 233 {+-} 1/T - 0.2283, valable de - 70 deg. C a -25 deg. C. (auteurs)

A review of phase separation in borosilicate glasses, with reference to nuclear fuel waste immobilization

International Nuclear Information System (INIS)

Taylor, P.

1990-08-01

This report reviews information on miscibility limits in borosilicate glass-forming systems. It includes both a literature survey and an account of experimental work performed within the Canadian Nuclear Fuel Waste Management Program. Emphasis is placed on the measurement and depiction of miscibility limits in multicomponent (mainly quaternary) systems, and the effects of individual components on the occurrence of phase separation. The behaviour of the multicomponent system is related to that of simpler (binary and ternary) glass systems. The possible occurrence of phase separation, as well as its avoidance, during processing of nuclear waste glasses is discussed

Liquid-Liquid Phase Separation in Model Nuclear Waste Glasses: A Solid-State Double-Resonance NMR Study

Energy Technology Data Exchange (ETDEWEB)

Martineau, Ch.; Michaelis, V.K.; Kroeker, S. [Univ Manitoba, Dept Chem, Winnipeg, MB R3T 2N2 (Canada); Schuller, S. [CEA Valrho Marcoule, LDMC, SECM, DTCD, DEN, F-30207 Bagnols Sur Ceze (France)

2010-07-01

Double-resonance nuclear magnetic resonance (NMR) techniques are used in addition to single-resonance NMR experiments to probe the degree of mixing between network-forming cations Si and B, along with the modifier cations Cs{sup +} and Na{sup +} in two molybdenum-bearing model nuclear waste glasses. The double-resonance experiments involving {sup 29}Si in natural abundance are made possible by the implementation of a CPMG pulse-train during the acquisition period of the usual REDOR experiments. For the glass with lower Mo content, the NMR results show a high degree of Si-B mixing, as well as an homogeneous distribution of the cations within the borosilicate network, characteristic of a non-phase-separated glass. For the higher-Mo glass, a decrease of B-Si(Q{sup 4}) mixing is observed, indicating phase separation. {sup 23}Na and {sup 133}Cs NMR results show that although the Cs{sup +} cations, which do not seem to be influenced by the molybdenum content, are spread within the borate network, there is a clustering of the Na{sup +} cations, very likely around the molybdate units. The segregation of a Mo-rich region with Na{sup +} cations appears to shift the bulk borosilicate glass composition toward the metastable liquid liquid immiscibility region and induce additional phase separation. Although no crystallization is observed in the present case, this liquid liquid phase separation is likely to be the first stage of crystallization that can occur at higher Mo loadings or be driven by heat treatment. From this study emerges a consistent picture of the nature and extent of such phase separation phenomena in Mo-bearing glasses, and demonstrates the potential of double-resonance NMR methods for the investigation of phase separation in amorphous materials. (authors)

Ductile Glass of Polyrotaxane Toughened by Stretch-Induced Intramolecular Phase Separation.

Science.gov (United States)

Kato, Kazuaki; Nemoto, Kaito; Mayumi, Koichi; Yokoyama, Hideaki; Ito, Kohzo

2017-09-27

A new class of ductile glasses is created from a thermoplastic polyrotaxane. The hard glass, which has a Young's modulus of 1 GPa, shows crazing, necking, and strain hardening with a total elongation of 330%. Stress concentration is prevented through a unique stretch-induced intramolecular phase separation of the cyclic components and the exposed backbone. In situ synchrotron X-ray scattering studies indicate that the backbone polymer chains slip through the cyclic components in the regions where the stress is concentrated.

Trajectory Analysis of Copper and Glass Particles in Electrostatic Separation for the Recycling of ASR

Directory of Open Access Journals (Sweden)

Beom-uk Kim

2017-10-01

Full Text Available Automobile-shredder-residue (ASR recycling techniques have been widely applied for improving the total recycling rate of end-of-life vehicles. In this study, to obtain useful information for predicting or improving ASR-separation efficiency, trajectory analyses of conductors (copper and non-conductors (glass were performed using a lab-scale induction electrostatic separator. The copper-wire trajectories obtained showed a good agreement depending significantly on the electric field strength and particle size. The observed copper-wire trajectories showed consistent congruity with the coarse-particles simulation (0.5 and 0.25 mm. The observed fine-particles (0.06 mm trajectory was deflected toward the (− attractive electrode, owing to the charge density effects due to the particle characteristics and relative humidity. This results in superior separation performance because more copper enters the conductor products bin. The actual dielectric-glass trajectory was deflected toward the (− attractive electrode, thus showing characteristics similar to conductive-particle characteristics. Through analyses conducted using a stereoscopic microscope, scanning electron microscope, and energy dispersive spectroscope, we found heterogeneous materials (fine ferrous particles and conductive organics on the glass surface. This demonstrates the separation-efficiency decrease for non-ferrous metals during electrostatic separation in the recycling of ASR. Future work should include a pretreatment process for eliminating impurities from the glass and advanced trajectory-simulation processes.

Lead recovery and high silica glass powder synthesis from waste CRT funnel glasses through carbon thermal reduction enhanced glass phase separation process

Energy Technology Data Exchange (ETDEWEB)

Xing, Mingfei [Henan Key Laboratory Cultivation Base of Mine Environmental Protection and Ecological Remediation, Henan Polytechnic University, Jiaozuo 454000 Henan China (China); Institute of Resource and Environment, Henan Polytechnic University, Jiaozuo 454000 Henan China (China); Fu, Zegang [Institute of Resource and Environment, Henan Polytechnic University, Jiaozuo 454000 Henan China (China); Wang, Yaping, E-mail: wangyp326@163.com [School of Surveying and Land Information Engineering, Henan Polytechnic University, Jiaozuo 454000, Henan China (China); Wang, Jingyu [Institute of Resource and Environment, Henan Polytechnic University, Jiaozuo 454000 Henan China (China); Zhang, Zhiyuan [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

2017-01-15

Highlights: • CRT funnel glass was remelted with B{sub 2}O{sub 3} in reducing atmosphere. • A part of PbO was reduced into Pb and detached from the glass phase. • The rest of PbO and other metal oxides were mainly concentrated in the B{sub 2}O{sub 3} phase. • PbO enriched in the interconnected B{sub 2}O{sub 3} phase can be completely leached out by HNO{sub 3}. • High silica glass powder(SiO{sub 2} purity >95%) was obtained after the leaching process. - Abstract: In this study, a novel process for the removal of toxic lead from the CRT funnel glass and synchronous preparation of high silica glass powder was developed by a carbon-thermal reduction enhanced glass phase separation process. CRT funnel glass was remelted with B{sub 2}O{sub 3} in reducing atmosphere. In the thermal process, a part of PbO contained in the funnel glass was reduced into metallic Pb and detached from the glass phase. The rest of PbO and other metal oxides (including Na{sub 2}O, K{sub 2}O, Al{sub 2}O{sub 3,} BaO and CaO) were mainly concentrated in the boric oxide phase. The metallic Pb phase and boric oxide phase were completely leached out by 5 mol/L HNO{sub 3}. The lead removal rate was 99.80% and high silica glass powder (SiO{sub 2} purity >95 wt%) was obtained by setting the temperature, B{sub 2}O{sub 3} added amount and holding time at 1000 °C, 20% and 30 mins, respectively. The prepared high silicate glass powders can be used as catalyst carrier, semipermeable membranes, adsorbents or be remelted into high silicate glass as an ideal substitute for quartz glass. Thus this study proposed an eco-friendly and economical process for recycling Pb-rich electronic glass waste.

Separation of hydrogen from dilute streams (e.g. using membranes)

Energy Technology Data Exchange (ETDEWEB)

Brueschke, H.E.A. [Sulzer Chemtech GmbH Membrantechnik, Neunkirchen (Germany)

2003-07-01

As a conclusion it can be stated that the use of membranes in the separation and purification of hydrogen is still limited. In areas where hydrogen at not too high purity can be recovered from otherwise low value gas mixtures, like in the examples given above, the application of membranes has developed into a proven state-of-art technology. Where high purity hydrogen at high pressure is demanded, still fairly large work is ahead for membrane and process developers. (orig.)

Characterization of Glass Fiber Separator Material for Lithium Batteries

Science.gov (United States)

Subbarao, S.; Frank, H.

1984-01-01

Characterization studies were carried out on a glass fiber paper that is currently employed as a separator material for some LiSOCl2 primary cells. The material is of the non-woven type made from microfilaments of E-type glass and contains an ethyl acrylate binder. Results from extraction studies and tensile testing revealed that the binder content and tensile strength of the paper were significantly less than values specified by the manufacturer. Scanning electron micrographs revealed the presence of clusters of impurities many of which were high in iron content. Results of emission spectroscopy revealed high overall levels of iron and leaching, followed by atomic absorption measurements, revealed that essentially all of this iron is soluble in SOCl2.

Deuterium isotope separation factor between hydrogen and liquid water

International Nuclear Information System (INIS)

Rolston, J.H.; den Hartog, J.; Butler, J.P.

1976-01-01

The overall deuterium isotope separation factor between hydrogen and liquid water, α, has been measured directly for the first time between 280 and 370 0 K. The data are in good agreement with values of α calculated from literature data on the equilibrium constant for isotopic exchange between hydrogen and water vapor, K 1 , and the liquid-vapor separation factor, α/sub V/. The temperature dependence of α over the range 273-473 0 K based upon these new experimental results and existing literature data is given by the equation ln α = -0.2143 + (368.9/T) + (27,870/T 2 ). Measurements on α/sub V/ given in the literature have been surveyed and the results are summarized over the same temperature range by the equation ln α/sub V/ = 0.0592 - (80.3/T) +

Alkali ion migration between stacked glass plates by corona discharge treatment

Energy Technology Data Exchange (ETDEWEB)

Kawaguchi, Keiga [Research Institute for Electronic Science, Hokkaido University, N20 W10, Kita-ku, Sapporo, Hokkaido 001-0020 (Japan); Suzuki, Toshio [Research Center, Asahi Glass Co., Ltd., 1150 Hazawa-cho, Kanagawa-ku, Yokohama, Kanagawa 221-8755 (Japan); Ikeda, Hiroshi [Art, Science and Technology Center for Cooperative Research, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Sakai, Daisuke [Department of Electrical and Electronic Engineering, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507 (Japan); Funatsu, Shiro; Uraji, Keiichiro [Production Technology Center, Asahi Glass Co., Ltd., 1-1 Suehiro-cyo, Tsurumiku, Yokohama, Kanagawa 230-0045 (Japan); Yamamoto, Kiyoshi [Research Center, Asahi Glass Co., Ltd., 1150 Hazawa-cho, Kanagawa-ku, Yokohama, Kanagawa 221-8755 (Japan); Harada, Kenji [Department of Computer Science, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507 (Japan); Nishii, Junji, E-mail: nishii@es.hokudai.ac.jp [Research Institute for Electronic Science, Hokkaido University, N20 W10, Kita-ku, Sapporo, Hokkaido 001-0020 (Japan)

2015-05-30

Highlights: • Two stacked glass plates with a 1 mm gap were treated by corona discharge. • Spatial migration of alkali ion over the gap was demonstrated. • Hydrogen gas was necessary for uniform migration. • Surface modification was done with this process without high temperature or vacuum. - Abstract: Corona discharge reflects the spatial migration of alkali ions over a gap between two glass plates. This study examined stacked glass plates containing different alkali ions treated with the corona discharge plasma generated by applied voltage of 4.5 kV at 200 °C. Protons generated at the anode electrode penetrate into the potassium-ion-containing upper glass plate, which is located 5 mm below the anode electrode. Potassium ions intruded into the lower glass plate containing sodium ions placed on the cathode electrode, even over a 1 mm gap separating the plates. Finally, the sodium ion discharged on the cathode electrode. The hydrogen atmosphere was effective at inhibiting the potassium ion reaction with ambient gases during the spatial migration between the two glass plates.

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-06-05

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

Hydrogen isotope separation in hydrophobic catalysts between hydrogen and liquid water

Energy Technology Data Exchange (ETDEWEB)

Ye, Linsen, E-mail: yls2005@mail.ustc.edu.cn [China Academy of Engineering Physics, Mianyang 621900 (China); Luo, Deli [Science and Technology on Surface Physics and Chemistry Laboratory, Jiangyou 621907 (China); Tang, Tao; Yang, Wan; Yang, Yong [China Academy of Engineering Physics, Mianyang 621900 (China)

2015-11-15

Hydrogen isotope catalytic exchange between hydrogen and liquid water is a very effective process for deuterium-depleted potable water production and heavy water detritiation. To improve the characteristics of hydrophobic catalysts for this type of reaction, foamed and cellular structures of hydrophobic carbon-supported platinum catalysts were successfully prepared. Separation of deuterium or tritium from liquid water was carried out by liquid-phase catalytic exchange. At a gas–liquid ratio of 1.53 and exchange temperature of 70 °C, the theoretical plate height of the hydrophobic catalyst (HETP = 34.2 cm) was slightly lower than previously reported values. Changing the concentration of the exchange column outlet water yielded nonlinear changes in the height of the packing layer. Configurations of deuterium-depleted potable water and detritiation of heavy water provide references for practical applications.

Effect of hydrogen environment on the separation of Fe grain boundaries

International Nuclear Information System (INIS)

Wang, Shuai; Martin, May L.; Robertson, Ian M.; Sofronis, Petros

2016-01-01

A density-functional theory based empirical potential was used to explore the energies of different types of Fe grain boundaries and free surfaces in thermodynamic equilibrium with a hydrogen environment. The classical model for calculating the ideal work of separation with solute atoms is extended to account for every trapping site. This yields the lowest-energy structures at different hydrogen chemical potentials (or gas pressures). At hydrogen gas pressures lower than 1000 atm, the reduction of the reversible work of separation is less than 33% and it increases to 36% at a gas pressure of 5000 atm. Near the hydride formation limit, 5 × 10 4  atm, the reduction is 44%. Based on the magnitude of these reductions for complete decohesion, and accounting for experimental observations of the microstructure associated with hydrogen-induced intergranular fracture of Fe, it is posited that hydrogen-enhanced plasticity and attendant effects establish the local conditions responsible for the transition in fracture mode from transgranular to intergranular. The conclusion is reached that intergranular failure occurs by a reduction of the cohesive energy but with contributions from structural as well as compositional changes in the grain boundary that are driven by hydrogen-enhanced plasticity processes.

South Aegean volcanic glass. Separation and analysis by INAA and EPMA

International Nuclear Information System (INIS)

Saminger, S.; Peltz, C.; Bichler, M.

2000-01-01

Pumice from the major volcanic sources (Milos, Nisyros, Yali, Kos and Santorini) in the South Aegean region was investigated to reveal the differences between the composition of the bulk material, which contains a certain percentage of crystallites, and the pure glass phase, which is the main constituent. The knowledge of these differences is important for the identification of vitric tephra layers found in the Eastern Mediterranean region in archaeological context, in deep sea drilling cores and lake sediments. Eruption products, deposited at some distance, show not only a decrease in their grain size, but also have usually lost their crystalline fraction due to gravity separation and consist only of glass shards. Major element distributions in such layers and in pumiceous glass are not sufficient for a reliable identification of the volcanic source, as several eruptions are known to have produced chemically very similar tephra layers in this region. Trace element data, especially of the rather immobile rare earth elements (REEs), can provide greater information on tephra originating from different volcanic eruptions. Therefore, a technique has been developed to separate the glass phase from different primary pumices to reveal differences in their trace element distributions. The concentrations of the major constituents, in particular Al, Ca, Fe, Mg, Mn, Na, Si, and Ti were determined by electron probe microanalysis (EPMA), those of Al, As, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Sm, Ta, Th, Ti, U, V, Yb and Zr by instrumental neutron activation analysis. Subtle differences between the compositions of the glass phase and the bulk material are explained by differentiation during partial crystallization. Their applicability to the classification of tephra layers is demonstrated. (author)

Study of phase separation and crystallization phenomena in soda-lime borosilicate glass enriched in MoO3

International Nuclear Information System (INIS)

Magnin, M.

2009-09-01

Molybdenum oxide immobilization (MoO 3 , as fission product) is one of the major challenges in the nuclear glass formulation issues for high level waste solutions conditioning since many years, these solutions arising from spent nuclear fuel reprocessing. Phase separation and crystallisation processes may arise in molten glass when the MoO 3 content is higher than its solubility limit that may depend on glass composition. Molybdenum combined with other elements such as alkali and alkaline-earth may form crystalline molybdates, known as 'yellow phases' in nuclear glasses which may decrease the glass durability. In order to confine high level wastes (HLW) such as the fission product solutions arising from the reprocessing of high burn-up UOX-type nuclear spent fuels, a new glass composition (HLW glass) is being optimized. This work is devoted to the study of the origin and the mechanism of phase separation and crystallization phenomena induced by molybdenum oxide incorporation in the HLW glass. From microstructural and structural point of view, the molybdenum oxide behavior was studied in glass compositions belonging to the SiO 2 -B 2 O 3 - Na 2 O-CaO simplified system which constituted basis for the HLW glass formulation. The structural role of molybdenum oxide in borosilicate network explaining the phase separation and crystallization tendency was studied through the coupling of structural ( 95 Mo, 29 Si, 11 B, 23 Na MAS NMR, XRD) and microstructural (SEM, HRTEM) analysis techniques. The determination of phase separation (critical temperature) and crystallization (liquidus temperature) appearance temperatures by in situ viscosimetry and Raman spectroscopy experiments allowed us to propose a transformation scenario during melt cooling. These processes and the nature of the crystalline phases formed (CaMoO 4 , Na 2 MoO 4 ) that depend on the evolution of MoO 3 , CaO and B 2 O 3 contents were correlated with changes of sodium and calcium cations proportions in the

Hydrogen isotope separation experience at the Savannah River Site

International Nuclear Information System (INIS)

Lee, M.W.

1993-01-01

Savannah River Site (SRS) is a sole producer of tritium for US Weapons Program. SRS has built Facilities, developed the tritium handling processes, and operated safely for the last forty years. Tritium is extracted from the irradiated reactor target, purified, mixed with deuterium, and loaded to the booster gas bottle in the weapon system for limited lifetime. Tritium is recovered from the retired bottle and recycled. Newly produced tritium is branded into the recycled tritium. One of the key process is the hydrogen isotope separation that tritium is separated from deuterium and protium. Several processes have been used for the hydrogen isotope separation at SRS: Thermal Diffusion Column (TD), Batch Cryogenic Still (CS), and Batch Chromatography called Fractional Sorption (FS). TD and CS requires straight vertical columns. The overall system separation factor depends on the length of the column. These are three story building high and difficult to put in glove box. FS is a batch process and slow operation. An improved continuous chromatographic process called Thermal Cycling Absorption Process (TCAP) has been developed. It is small enough to be about to put in a glove box yet high capacity comparable to CS. The SRS tritium purification processes can be directly applicable to the Fusion Fuel Cycle System of the fusion reactor

Studies on hydrogen separation membrane for IS process. Membrane preparation with porous α-alumina tube

International Nuclear Information System (INIS)

Hwang, Gab-Jin; Onuki, Kaoru; Shimizu, Saburo

1998-01-01

It was investigated the preparation technique of hydrogen separation membrane to enhance the decomposition ratio of hydrogen iodide in the thermochemical IS process. Hydrogen separation membranes based on porous α-alumina tubes having pore size of 100 nm and 10 nm were prepared by chemical vapor deposition using tetraethylorthosilicate (TEOS) as the Si source. In the hydrogen separation membrane, its pore was closed by the deposited silica and then the permeation of gas was affected by the hindrance diffusion. At 600degC, the selectivity ratios (H 2 /N 2 ) were 5.2 and 160 for the membranes based on porous α-alumina tube having pore size of 100 nm and 10 nm, respectively. (author)

Conceptual design of hydrogen isotopes chromatographic separation system with super large capacity

International Nuclear Information System (INIS)

Xie Bo; Weng Kuiping; Liu Yunnu; Hou Jianping

2012-01-01

A super large capacity hydrogen isotopes separation system, including total plan, unit (including making and purification of gas, three-grade chromatographic columns, gas loop and auto-control, and carrier recovery) and experimental scheme, had been designed on the basis of a series of hydrogen-deuterium experiments by temperature programmed de- sorption. The characteristic of the system was that desorption kinetic parameters could be directly calculated from the hydrogen isotope separation desorption spectra information. In other words, the complicated dynamic process of separation could be described by the desorption rate equation, shape parameter and desorption activation energy calculation on the condition of the experimental data and appropriate assumptions (equilibrium and adsorption, uniform surface). In previous work, an experimental series of operation to verify the successive enrichment of D 2 from a H 2 -D 2 mixture, the production of the deuterium from natural hydrogen and the recovery of tritium such as from the nuclear heavy-water were carried out using MS5A at 77 K. This work was only conceptual design, so it was necessary to identify the availability of super large capacity system by experiment. (authors)

Study on glass-forming ability and hydrogen storage properties of amorphous Mg60Ni30La10−xCox (x = 0, 4) alloys

International Nuclear Information System (INIS)

Lv, Peng; Wang, Zhong-min; Zhang, Huai-gang; Balogun, Muhammad-Sadeeq; Ji, Zi-jun; Deng, Jian-qiu; Zhou, Huai-ying

2013-01-01

Mg 60 Ni 30 La 10−x Co x (x = 0, 4) amorphous alloys were prepared by rapid solidification, using a melt-spinning technique. X-ray diffraction and differential scanning calorimetry analysis were employed to measure their microstructure, thermal stability and glass-forming ability, and hydrogen storage properties were studied by means of PCTPro2000. Based on differential scanning calorimetry results, their glass-forming ability and thermal stability were investigated by Kissinger method, Lasocka curves and atomic cluster model, respectively. The results indicate that glass-forming ability, thermal properties and hydrogen storage properties in the Mg-rich corner of Mg–Ni–La–Co system alloys were enhanced by Co substitution for La. It can be found that the smaller activation energy (ΔΕ) and frequency factor (υ 0 ), the bigger value of B (glass transition point in Lasocka curves), and higher glass-forming ability of Mg–Ni–La–Co alloys would be followed. In addition, atomic structure parameter (λ), deduced from atomic cluster model is valuable in the design of Mg–Ni–La–Co system alloys with good glass-forming ability. With an increase of Co content from 0 to 4, the hydrogen desorption capacity within 4000 s rises from 2.25 to 2.85 wt.% at 573 K. - Highlights: • Amorphous Mg 60 Ni 30 La 10−x Co x (x = 0 and 4) alloys were produced by melt spinning. • The GFA and hydrogen storage properties were enhanced by Co substitution for La. • With an increase of Co content, the hydrogen desorption capacity rises at 573 K

Hydrogen Separation by Natural Zeolite Composite Membranes: Single and Multicomponent Gas Transport.

Science.gov (United States)

Farjoo, Afrooz; Kuznicki, Steve M; Sadrzadeh, Mohtada

2017-10-06

Single and multicomponent gas permeation tests were used to evaluate the performance of metal-supported clinoptilolite membranes. The efficiency of hydrogen separation from lower hydrocarbons (methane, ethane, and ethylene) was studied within the temperature and pressure ranges of 25-600 °C and 110-160 kPa, respectively. The hydrogen separation factor was found to reduce noticeably in the gas mixture compared with single gas experiments at 25 °C. The difference between the single and multicomponent gas results decreased as the temperature increased to higher than 300 °C, which is when the competitive adsorption-diffusion mechanism was replaced by Knudsen diffusion or activated diffusion mechanisms. To evaluate the effect of gas adsorption, the zeolite surface isotherms of each gas in the mixture were obtained from 25 °C to 600 °C. The results indicated negligible adsorption of individual gases at temperatures higher than 300 °C. Increasing the feed pressure resulted in a higher separation efficiency for the individual gases compared with the multicomponent mixture, due to the governing effect of the adsorptive mechanism. This study provides valuable insight into the application of natural zeolites for the separation of hydrogen from a mixture of hydrocarbons.

Proposed configuration for ITER hydrogen isotope separation system (ISS)

International Nuclear Information System (INIS)

Lazar, A.; Brad, S.; Sofalca, N.; Vijulie, M.; Cristescu, I.; Doer, L; Wurster, W.

2008-01-01

Full text: The isotope separation system utilizes cryogenic distillation and catalytic reaction for isotope exchange to separate elemental hydrogen isotope gas mixtures. The ISS shall separate hydrogen isotope mixtures from two sources to produce up to five different products. These are: protium, effluent for discharge to the atmosphere, deuterium for fuelling, deuterium for NB injector (NBI) source gas, 50 % and 90% T fuelling streams. The concept of equipment 3D layout for the ISS main components were developed using the Part Design, Assembly Design, Piping Design, Equipment Arrangement and Plant Layout application from CATIA V5. The 3D conceptual layouts for ISS system were created having as reference the DDD -32-B report, the drawings 0028.0001.2D. 0100. R 'Process Flow Diagram'; 0029.0001.2D. 0200.R 'Process Instrumentation Diagram -1' (in the cold box); 0030.0001.2D. 0100. R 'Process Instrumentation Diagram -2' (in the hard shell confinement) and imputes from TLK team. The main components designed for ISS are: ISS cold box system (CB) with cryogenic distillation columns (CD) and recovery heat exchangers (HX), ISS hard shell containment (HSC) system with metals bellow pumps (MB) and chemical equilibrators (RC), valve box system, instrumentation box system, vacuum system and hydrogen expansion vessels. Work related to these topics belongs to the contract FU06-CT-2006-00508 (EFDA 06-1511) from the EFDA Technology Workprogramm 2006 and was done in collaboration with FZK Association team during the period January 2007 - September 2008. (authors)

Transport Reactor Development Unit Modification to Provide a Syngas Slipstream at Elevated Conditions to Enable Separation of 100 LB/D of Hydrogen by Hydrogen Separation Membranes Year - 6 Activity 1.15 - Development of a National Center for Hydrogen Technology

Energy Technology Data Exchange (ETDEWEB)

Schlasner, Steven

2012-03-01

Gasification of coal when associated with carbon dioxide capture and sequestration has the potential to provide low-cost as well as low-carbon hydrogen for electric power, fuels or chemicals production. The key element to the success of this concept is inexpensive, effective separation of hydrogen from carbon dioxide in synthesis gas. Many studies indicate that membrane technology is one of the most, if not the most, economical means of accomplishing separation; however, the advancement of hydrogen separation membrane technology is hampered by the absence of experience or demonstration that the technology is effective economically and environmentally at larger scales. While encouraging performance has been observed at bench scale (less than 12 lb/d hydrogen), it would be imprudent to pursue a largescale demonstration without testing at least one intermediate scale, such as 100 lb/d hydrogen. Among its many gasifiers, the Energy & Environmental Research Center is home to the transport reactor demonstration unit (TRDU), a unit capable of firing 200—500 lb/hr of coal to produce 400 scfm of synthesis gas containing more than 200 lb/d of hydrogen. The TRDU and associated downstream processing equipment has demonstrated the capability of producing a syngas over a wide range of temperatures and contaminant levels — some of which approximate conditions of commercial-scale gasifiers. Until this activity, however, the maximum pressure of the TRDU’ s product syngas was 120 psig, well below the 400+ psig pressures of existing large gasifiers. This activity installed a high-temperature compressor capable of accepting the range of TRDU products up to 450°F and compressing them to 500 psig, a pressure comparable to some large scale gasifiers. Thus, with heating or cooling downstream of the TRDU compressor, the unit is now able to present a near-raw to clean gasifier synthesis gas containing more than 100 lb/d of hydrogen at up to 500 psig over a wide range of temperatures

Determination of the deuterium separation factor between ammonia and hydrogen

International Nuclear Information System (INIS)

Ravoire, J.; Grandcollot, P.; Dirian, G.; Montel, J.

1963-01-01

The separation factors between hydrogen and gaseous ammonia (α g ) and between hydrogen and liquid ammonia (α l ) have been determined by experimental measurements and by calculations from spectrographic data, using existing data concerning the separation factor between liquid ammonia and gaseous ammonia (α v ). The values of α v , α g and α l are given in a table for a temperature range between - 70 deg C and + 40 deg C. The following equations have been established: log α g = 218 ± 1/T - 0.1841, from - 70 deg. C to + 40 deg. C. log α g = 216 ± 1/T + Q, valid at every temperature, Q being known as a function of temperature. log α l = 233 ± 1/T - 0.2283, from - 70 deg. C a -25 deg. C. (authors) [fr

Electrochemical Separation, Pumping, and Storage of Hydrogen or Oxygen into Nanocapillaries Via High Pressure MEA Seals

Science.gov (United States)

2015-10-13

412TW-PA-15560 Electrochemical Separation, Pumping, and Storage of Hydrogen or Oxygen into Nanocapillaries Via High Pressure MEA Seals...TITLE AND SUBTITLE Electrochemical Separation, Pumping, and Storage of Hydrogen or Oxygen into Nanocapillaries Via High Pressure MEA Seals...density storage of gases remains a major technological hurdle for many fields. The U.S. Department of Energy (DOE), for example, reduced their hydrogen

Closed-cell polymeric foam for hydrogen separation and storage

Czech Academy of Sciences Publication Activity Database

Pientka, Zbyněk; Pokorný, P.; Bélafi-Bakó, K.

2007-01-01

Roč. 304, 1-2 (2007), s. 82-87 ISSN 0376-7388 R&D Projects: GA ČR GA203/06/1207 Institutional research plan: CEZ:AV0Z40500505 Keywords : polymeric foam * gas separation * hydrogen storage Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.432, year: 2007

Mechanically driven phase separation and corresponding microhardness change in Cu60Zr20Ti20 bulk metallic glass

DEFF Research Database (Denmark)

Cao, Q.P.; Li, J.F.; Zhou, Y.H.

2005-01-01

Rolling deformation of bulk Cu60Zr20Ti20 metallic glass has been performed at cryogenic temperature. The specimens exhibit excellent ductility, and are rolled up to 97% reduction in thickness without fracture. Crystallization is suppressed during the deformation, however, phase separation is obse...... is observed in the glassy matrix when the thickness reduction exceeds 89%. Once the phase separation occurs, the microhardness of the specimen increases drastically, indicating the existence of work hardening by severe plastic deformation of the metallic glass.......Rolling deformation of bulk Cu60Zr20Ti20 metallic glass has been performed at cryogenic temperature. The specimens exhibit excellent ductility, and are rolled up to 97% reduction in thickness without fracture. Crystallization is suppressed during the deformation, however, phase separation...

A new combined nanoSIMS and continuous-flow IRMS approach to measure hydrogen isotopes from water in hydrated rhyolitic glass

Science.gov (United States)

Gatti, E.; Kitchen, N.; Newman, S.; Guan, Y.; Westgate, J.; Pearce, N. J. G.; Nikolic, D.; Eiler, J. M.

2016-12-01

The hydrogen-isotope value of water of hydration (or secondary water) preserved in rhyolitic glasses may provide significant insights regarding the climate at the time of their deposition and the impact of super-eruptions upon the environment. However, the ability of the glass to retain the environmental D/H isotopic signal after hydration needs to be tested, since modifications to the D/H systematics may result from the continuous exchange of D/H with the atmosphere or condensed water after initial glass hydration. Ideal geological archives to test whether the glass retains its original hydrogen signal are sediments in natural waters and ice cores, which preserve tephra in constrained horizons that can be independently isotopically characterised. However, tephra in marine and fresh water sediments and ice cores are often present in concentrations of the order of 1000 grains/cm3 (IRMS methods require much more material ( 100-500 mg) and therefore cannot be applied. We present here a new integrated nanoSIMS and continuous flow IRMS approach to understand how water is distributed within single glass grains (diffusion profiles), quantify the time of hydration of young (Holocene) and old (Miocene) already well-characterised rhyolitic glasses, and measure the D/H ratio of the hydration water on single grains and bulk material consisting of only approximately 0.1-1 mg. The IRMS method measures the absolute abundance of hydrogen released from the sample by continuous-flow mass spectrometry. Current data indicates that the method can accurately measure a hydrogen signal from a rock sample containing at least 400 nanomoles of H2, corresponding to 70 µg of water, which translates to 1 mg of hydrous glass (>3 wt%) or 15 mg of dry ( 0.5 wt%) obsidian chips. The method can be improved by reducing the blank to IRMS method will be compared to sub-micron mapping of single-grains using a high-resolution ion microprobe, the CAMECA NanoSIMS 50L, in the Microanalysis Center for

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

Hydrogen Separation by Natural Zeolite Composite Membranes: Single and Multicomponent Gas Transport

Directory of Open Access Journals (Sweden)

Afrooz Farjoo

2017-10-01

Full Text Available Single and multicomponent gas permeation tests were used to evaluate the performance of metal-supported clinoptilolite membranes. The efficiency of hydrogen separation from lower hydrocarbons (methane, ethane, and ethylene was studied within the temperature and pressure ranges of 25–600 °C and 110–160 kPa, respectively. The hydrogen separation factor was found to reduce noticeably in the gas mixture compared with single gas experiments at 25 °C. The difference between the single and multicomponent gas results decreased as the temperature increased to higher than 300 °C, which is when the competitive adsorption–diffusion mechanism was replaced by Knudsen diffusion or activated diffusion mechanisms. To evaluate the effect of gas adsorption, the zeolite surface isotherms of each gas in the mixture were obtained from 25 °C to 600 °C. The results indicated negligible adsorption of individual gases at temperatures higher than 300 °C. Increasing the feed pressure resulted in a higher separation efficiency for the individual gases compared with the multicomponent mixture, due to the governing effect of the adsorptive mechanism. This study provides valuable insight into the application of natural zeolites for the separation of hydrogen from a mixture of hydrocarbons.

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

Ceramic membranes for high temperature hydrogen separation

Energy Technology Data Exchange (ETDEWEB)

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

1996-08-01

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

Thermal decomposition of hydroiodic acid and hydrogen separation

International Nuclear Information System (INIS)

Yeheskel, J.; Leger, D.; Courvoisier, P.

1978-01-01

The reaction of decomposition of hydroiodic acid is included in a promising water splitting process (sulfur-iodine cycle). An experimental program is running in order to overcome some basic difficulties and data shortcomings which stand in the way of achieving that target. The core of the experimental system is the palladium silver (23% Ag) membrane tube reactor in which the feed gas entered the inner side of the tube. Four series of different kinds of experiments have been performed: 1) diffusion of hydrogen from a pure feed hydrogen stream through the membrane; the results are statistically analyzed due to the present correlations of the H 2 specific permeability as a function of temperature and pressure (up to 600 0 C and 20 bar); 2) separation of hydrogen from a binary feed mixture H 2 -He; a mathematical model is developed for this operation; 3) indication of the poisoning effect of a little amount of hydroiodic acid on the hydrogen pereability; this effect is partly reversible at high temperatures; 4) a performance of one continuous experiment of HI decomposition into the membrane tube at steady pressure and temperature of 8 bar and 500 0 C; the results prove the catalytic activity of the membrane surface

A new type separation column for the water-hydrogen isotope catalytic exchange process

International Nuclear Information System (INIS)

Fedorchenko, O.A.; Alekseev, I.A.; Trenin, V.D.

2001-01-01

The catalytic water/hydrogen isotope exchange process is by right considered the most attractive for the solution a number of urgent problems of hydrogen isotope separation. A new type exchange reaction column is described and studied in details by computer simulation and with the help of McCabe-Thiele diagrams. It is shown that the new column in comparison with a traditional one needs less catalyst quantity and a smaller diameter for the solving of the same separation tasks. Generalized calculation data are presented in graphical form

Ceramic membranes for high temperature hydrogen separation

Energy Technology Data Exchange (ETDEWEB)

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

1997-12-01

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

Mixed protonic-electronic conductors for hydrogen separation membranes

Science.gov (United States)

Song, Sun-Ju

2003-10-01

The chemical functionality of mixed protonic-electronic conductors arises out of the nature of the defect structure controlled by thermodynamic defect equilibria of the materials, and results in the ability to transport charged species. This dissertation is to develop a fundamental understanding of defect chemistry and transport properties of mixed protonic-electronic conducting perovskites for hydrogen separation membranes. Furthermore, it was aimed to develop the algorithm to predict how these properties affect the permeability in chemical potential gradients. From this objective, first of all, the appropriate equations governing proton incorporation into perovskite oxides were suggested and the computer simulation of defect concentrations across a membrane oxide under various conditions were performed. Electrical properties of p-type electronic defects at oxidizing conditions and n-type electrical properties of SrCe 0.95Eu0.05O3-delta at reducing atmospheres were studied. Defect equilibrium diagrams as a function of PO2 , PH2O ) produced from the Brouwer method were verified by computational simulation and electrical conductivity measurements. The chemical diffusion of hydrogen through oxide membranes was described within the framework of Wagner's chemical diffusion theory and it was solved without any simplifying assumptions on functional dependence of partial conductivity due to the successful numerical modeling of partial conductivities as a function of both hydrogen and oxygen partial pressures. Finally the hydrogen permeability of Eu and Sm doped SrCeO3-delta was studied as a function of temperature, hydrogen partial pressure gradient, and water vapor pressure gradient. The dopant dependence of hydrogen permeability was explained in terms of the difference in ionization energy and ionic radius of dopant.

Luminescence of MnS in glasses: spectroscopic probe for the study of thermal phase separation

Energy Technology Data Exchange (ETDEWEB)

Menassa, P E

1984-01-01

A new approach for studying thermal phase separation in sodium borosilicate glasses using MnS as a luminescent probe is investigated. Seventy-one samples of glasses activated by MnS inside and around the Na2O.B2O3.SiO2 miscibility gaps were prepared. These samples were then phase separated by dry thermal treatment. It is shown that on addition of MnO, the ternary Na2O.B2O3.SiO2 system behaved like other quaternary systems of the type X2O.MO.B2O3.SiO2 (X = Na, K; M = Mg, Ca, Ba, Zn). Scanning electron microscopy and X-ray microanalysis demonstrated that manganese concentrates preferentially in the boron-rich phase. This, analysis, in conjuction with a comparison of MnS emission spectra of upheated and heat treated glasses shows that the glasses are submicroscopically phase separated when prepared. The decay-time analysis of MnS luminescence indicates that the low energy emission band arises from MnS in the boron-rich phase while the high energy emission is due to MnS in the silica-rich phase. The difference in the crystal field parameters obtained from the excitation spectra of the two emission bands shows that the high energy emission band is from MnS in tetrahedral sites while the low energy emission band is from MnS in an octahedral environment.

Development of Hydrogen Separation Module with Structured Catalyst for Use in Membrane Reformer

International Nuclear Information System (INIS)

Isamu Yasuda; Tatsuya Tsuneki; Yoshinori Shirasaki; Toru Shimamori; Hidekazu Shigaki; Hiroyuki Tanaka

2006-01-01

A new type of hydrogen separation module for use in a membrane reformer was proposed and developed. The new module, what we call MOC (Membrane On Catalyst), was designed to have a membrane of palladium-based alloy prepared on the surface of the tubular structured catalyst that has catalytic activity for steam reforming reaction, thermal expansion matching with the membrane material, proper porosity, mechanical strength and thermal conductivity. The best composition of the structured catalyst was identified in the composites of metallic Ni and YSZ (Yttria-Stabilized Zirconia). A hydrogen separation module was manufactured by electroless plating of Pd with thickness of 7 to 15 microns on the surface of porous sintered tube of Ni-YSZ with an approximate size of 9 mm in diameter and 100 mm in length. The hydrogen permeability measurements have shown hydrogen flux of 25 to 35 cc/min at 550 to 600 C, which is higher than the permeability of the conventional modules using rolled Pd film. (authors)

Lanthanide-activated Na5Gd9F32 nanocrystals precipitated from a borosilicate glass: Phase-separation-controlled crystallization and optical property

International Nuclear Information System (INIS)

Chen, Daqin; Wan, Zhongyi; Zhou, Yang; Chen, Yan; Yu, Hua; Lu, Hongwei; Ji, Zhenguo; Huang, Ping

2015-01-01

Highlights: • Na 5 Gd 9 F 32 nanocrystals embedded glass ceramics were fabricated for the first time. • Such glass ceramics were achieved by phase-separation-controlled crystallization. • Elemental mapping evidenced the segregation of activators into the Na 5 Gd 9 F 32 lattice. • Luminescent color could be tuned by controlling glass crystallization temperature. - Abstract: Lanthanide-activated cubic Na 5 Gd 9 F 32 nanocrystals were precipitated from a borosilicate glass with a specifically designed composition. The precursor glass is already phase-separated after melt-quenching, which is beneficial to the realization of the controllable glass crystallization for affording desirable size, morphology and activator partition. Elemental mapping in the scanning transmission electron microscopy evidenced that the segregation of lanthanide ions into the Na 5 Gd 9 F 32 lattice was in situ formed without the requirement of long-range ionic diffusion. Impressively, such fabricated glass ceramic co-doped with Yb 3+ /Er 3+ ions exhibited intense upconversion luminescence, which was about 500 times higher than that of the precursor glass, and its luminescent color could be easily tuned from red to green by controlling glass crystallization temperature. It is anticipated that such phase-separation synthesis strategy with precise control over nanostructure of glass ceramics offer a great opportunity to design other highly transparent nanocomposites with a wide range of tunable optical properties

Next-generation TCAP hydrogen isotope separation process

International Nuclear Information System (INIS)

Heung, L. K.; Sessions, H. T.; Poore, A. S.; Jacobs, W. D.; Williams, C. S.

2008-01-01

A thermal cycling absorption process (TCAP) for hydrogen isotope separation has been in operation at Savannah River Site since 1994. The process uses a hot/cold nitrogen system to cycle the temperature of the separation column. The hot/cold nitrogen system requires the use of large compressors, heat exchanges, valves and piping that is bulky and maintenance intensive. A new compact thermal cycling (CTC) design has recently been developed. This new design uses liquid nitrogen tubes and electric heaters to heat and cool the column directly so that the bulky hot/cold nitrogen system can be eliminated. This CTC design is simple and is easy to implement, and will be the next generation TCAP system at SRS. A twelve-meter column has been fabricated and installed in the laboratory to demonstrate its performance. The design of the system and its test results to date is discussed. (authors)

WATER-GAS SHIFT WITH INTEGRATED HYDROGEN SEPARATION; A

International Nuclear Information System (INIS)

Maria Flytzani-Stephanopoulos; Jerry Meldon; Xiaomei Qi

2001-01-01

Optimization of the water-gas shift (WGS) reaction system for hydrogen production for fuel cells is of particular interest to the energy industry. To this end, it is desirable to couple the WGS reaction to hydrogen separation using a semi-permeable membrane, with both processes carried out at high temperature to improve reaction kinetics. Reduced equilibrium conversion of the WGS reaction at high temperatures is overcome by product H(sub 2) removal via the membrane. This project involves fundamental research and development of novel cerium oxide-based catalysts for the water-gas-shift reaction and the integration of these catalysts with Pd-alloy H(sub 2)-separation membranes supplying high purity hydrogen for fuel cell use. Conditions matching the requirements of coal gasifier-exit gas streams will be examined in the project. In the first year of the project, we prepared a series of nanostructured Cu- and Fe-containing ceria catalysts by a special gelation/precipitation technique followed by air calcination at 650 C. Each sample was characterized by ICP for elemental composition analysis, BET-N2 desorption for surface area measurement, and by temperature-programmed reduction in H(sub 2) to evaluate catalyst reducibility. Screening WGS tests with catalyst powders were conducted in a flow microreactor at temperatures in the range of 200-550 C. On the basis of both activity and stability of catalysts in simulated coal gas, and in CO(sub 2)-rich gases, a Cu-CeO(sub 2) catalyst formulation was selected for further study in this project. Details from the catalyst development and testing work are given in this report. Also in this report, we present H(sub 2) permeation data collected with unsupported flat membranes of pure Pd and Pd-alloys over a wide temperature window

Early evaluation of hydrogen isotopes separation by V4Cr4Ti-based sorbents at low temperatures

Energy Technology Data Exchange (ETDEWEB)

Kulsartov, Timur, E-mail: tima@physics.kz [Institute of Experimental and Theoretical Physics of Kazakh National University, 050038 Almaty (Kazakhstan); Institute of Atomic Energy of National Nuclear Center, 071100 Kurchatov (Kazakhstan); Shestakov, Vladimir; Chikhray, Yevgen; Kenzhina, Inesh; Askerbekov, Saulet [Institute of Experimental and Theoretical Physics of Kazakh National University, 050038 Almaty (Kazakhstan); Gordienko, Yuriy; Ponkratov, Yuriy; Zaurbekova, Zhanna [Institute of Atomic Energy of National Nuclear Center, 071100 Kurchatov (Kazakhstan)

2016-12-15

This paper presents the results of experiments on hydrogen isotopes sorption with V4Cr4Ti vanadium alloys from a mixture of hydrogen isotopes. The studies were carried out at temperatures of 353 K, 393 K, 423 K; and pressures of 10{sup 3}–10{sup 4} Pa in gas mixture of hydrogen isotopes. The α-phase domain of V-H (D) system was studied, where the concentration of hydrogen isotopes atoms should not exceed 0.015H (D) atoms per metal atom. The separation parameters were derived for several saturation conditions accordingly to registered time dependences of hydrogen isotopes partial pressure drop. The conclusion was made about the prospects of using vanadium alloys in hydrogen isotopes separation and purification systems.

Scalable air cathode microbial fuel cells using glass fiber separators, plastic mesh supporters, and graphite fiber brush anodes

KAUST Repository

Zhang, Xiaoyuan

2011-01-01

The combined use of brush anodes and glass fiber (GF1) separators, and plastic mesh supporters were used here for the first time to create a scalable microbial fuel cell architecture. Separators prevented short circuiting of closely-spaced electrodes, and cathode supporters were used to avoid water gaps between the separator and cathode that can reduce power production. The maximum power density with a separator and supporter and a single cathode was 75±1W/m3. Removing the separator decreased power by 8%. Adding a second cathode increased power to 154±1W/m3. Current was increased by connecting two MFCs connected in parallel. These results show that brush anodes, combined with a glass fiber separator and a plastic mesh supporter, produce a useful MFC architecture that is inherently scalable due to good insulation between the electrodes and a compact architecture. © 2010 Elsevier Ltd.

Separation of tritium from other hydrogen isotopes

International Nuclear Information System (INIS)

Roth, E.

1988-01-01

The paper describes a plant that has been operated at Marcoule for tritium production and used thermal diffusion enrichment, a facility that was built in Saclay to enrich hydrogen in tritium for low level measurements, and the Laue Langevin Institute tritium extraction plant. Details are given on the project under construction for the tritium separation facility at JET using Gas Chromatography, and on proposals for circuits for NET. Studies on catalysers for liquid phase catalytic exchange, on electrolysers, or different gas chromatography arrangements, are described. Systems designed for reprocessing plants, for detritiation of heavy water by distillation are briefly accounted for

Modelling of fast hydrogen permeability of alloys for membrane gas separation

Science.gov (United States)

Zaika, Yu. V.; Rodchenkova, N. I.

2017-05-01

The method of measuring the specific hydrogen permeability is used to study various alloys that are promising for gas separation installations. The nonlinear boundary value problem of hydrogen permeability complying with the specific features of the experiment and its modifications taking into account the high transfer rate is presented. Substantial difference from the quasi-equilibrium model (Richardson approximation in the assumption of the equilibrium Sieverts' law near the surface) has been discussed. The model is tested on published experimental data on Ta77Nb23 alloy.

Wafer-level manufacturing technology of glass microlenses

Science.gov (United States)

Gossner, U.; Hoeftmann, T.; Wieland, R.; Hansch, W.

2014-08-01

In high-tech products, there is an increasing demand to integrate glass lenses into complex micro systems. Especially in the lighting industry LEDs and laser diodes used for automotive applications require encapsulated micro lenses. To enable low-cost production, manufacturing of micro lenses on wafer level base using a replication technology is a key technology. This requires accurate forming of thousands of lenses with a diameter of 1-2 mm on a 200 mm wafer compliant with mass production. The article will discuss the technical aspects of a lens manufacturing replication process and the challenges, which need to be solved: choice of an appropriate master for replication, thermally robust interlayer coating, choice of replica glass, bonding and separation procedure. A promising approach for the master substrate material is based on a lens structured high-quality glass wafer with high melting point covered by a coating layer of amorphous silicon or germanium. This layer serves as an interlayer for the glass bonding process. Low pressure chemical vapor deposition and plasma enhanced chemical vapor deposition processes allow a deposition of layer coatings with different hydrogen and doping content influencing their chemical and physical behavior. A time reduced molding process using a float glass enables the formation of high quality lenses while preserving the recyclability of the mother substrate. The challenge is the separation of the replica from the master mold. An overview of chemical methods based on optimized etching of coating layer through small channels will be given and the impact of glass etching on surface roughness is discussed.

Hydrogen enrichment and separation from synthesis gas by the use of a membrane reactor

International Nuclear Information System (INIS)

Sanchez, J.M.; Barreiro, M.M.; Marono, M.

2011-01-01

One of the objectives of the CHRISGAS project was to study innovative gas separation and gas upgrading systems that have not been developed sufficiently yet to be tested at a demonstration scale within the time frame of the project, but which show some attractive merits and features for further development. In this framework CIEMAT studied, at bench scale, hydrogen enrichment and separation from syngas by the use of membranes and membrane catalytic reactors. In this paper results about hydrogen separation from synthesis gas by means of selective membranes are presented. Studies dealt with the evaluation of permeation and selectivity to hydrogen of prepared and pre-commercial Pd-based membranes. Whereas prepared membranes turned out to be non-selective, due to discontinuities of the palladium layer, studies conducted with the pre-commercial membrane showed that by means of a membrane reactor it is possible to completely separate hydrogen from the other gas components and produce pure hydrogen as a permeate stream, even in the case of complex reaction system (H 2 /CO/CO 2 /H 2 O) under WGS conditions gas mixtures. The advantages of using a water-gas shift membrane reactor (MR) over a traditional fixed bed reactor (TR) have also been studied. The experimental device included the pre-commercial Pd-based membrane and a commercial high temperature Fe-Cr-based, WGS catalyst, which was packed in the annulus between the membrane and the reactor outer shell. Results show that in the MR concept, removal of H 2 from the reaction side has a positive effect on WGS reaction, reaching higher CO conversion than in a traditional packed bed reactor at a given temperature. On increasing pressure on the reaction side permeation is enhanced and hence carbon monoxide conversion increases. -- Highlights: → H 2 enrichment and separation using a bench-scale membrane reactor MR is studied. → Permeation and selectivity to H 2 of Pd-based membranes was determined. → Complete separation

Separation of rate processes for isotopic exchange between hydrogen and liquid water in packed columns 10

International Nuclear Information System (INIS)

Butler, J.P.; Hartog, J. den; Goodale, J.W.; Rolston, J.H.

1977-01-01

Wetproofed platinum catalysts in packed columns promote isotopic exchange between counter-current streams of hydrogen saturated with water vapour and liquid water. The net rate of deuterium transfer from isotopically enriched hydrogen has been measured and separated into two rate processes involving the transfer of deuterium from hydrogen to water vapour and from water vapour to liquid. These are compared with independent measurements of the two rate processes to test the two-step successive exchange model for trickle bed reactors. The separated transfer rates are independent of bed height and characterize the deuterium concentrations of each stream along the length of the bed. The dependences of the transfer rates upon hydrogen and liquid flow, hydrogen pressure, platinum loading and the effect of dilution of the hydrophobic catalyst with inert hydrophilic packing are reported. The results indicate a third process may be important in the transfer of deuterium between hydrogen and liquid water. (author)

Optical properties of thermally reduced bismuth-doped sodium aluminosilicate glasses

DEFF Research Database (Denmark)

Nielsen, K.H.; Smedskjær, Morten Mattrup; Yue, Yuanzheng

Heat-treatment of multivalent ion containing glasses in a hydrogen atmosphere may cause both reduction of the multivalent ions and ionic inward diffusion, resulting in improved glass properties. Bismuth-doped glasses are also interesting objects not only concerning the reduction induced diffusion...... pressure of hydrogen. Here, we present results on the effect of the heat-treatment on the optical properties of bismuth-doped sodium aluminosilicate glasses.......Heat-treatment of multivalent ion containing glasses in a hydrogen atmosphere may cause both reduction of the multivalent ions and ionic inward diffusion, resulting in improved glass properties. Bismuth-doped glasses are also interesting objects not only concerning the reduction induced diffusion...

Scalable air cathode microbial fuel cells using glass fiber separators, plastic mesh supporters, and graphite fiber brush anodes

KAUST Repository

Zhang, Xiaoyuan; Cheng, Shaoan; Liang, Peng; Huang, Xia; Logan, Bruce E.

2011-01-01

The combined use of brush anodes and glass fiber (GF1) separators, and plastic mesh supporters were used here for the first time to create a scalable microbial fuel cell architecture. Separators prevented short circuiting of closely

Interfacial separation of a mature biofilm from a glass surface - A combined experimental and cohesive zone modelling approach.

Science.gov (United States)

Safari, Ashkan; Tukovic, Zeljko; Cardiff, Philip; Walter, Maik; Casey, Eoin; Ivankovic, Alojz

2016-02-01

A good understanding of the mechanical stability of biofilms is essential for biofouling management, particularly when mechanical forces are used. Previous biofilm studies lack a damage-based theoretical model to describe the biofilm separation from a surface. The purpose of the current study was to investigate the interfacial separation of a mature biofilm from a rigid glass substrate using a combined experimental and numerical modelling approach. In the current work, the biofilm-glass interfacial separation process was investigated under tensile and shear stresses at the macroscale level, known as modes I and II failure mechanisms respectively. The numerical simulations were performed using a Finite Volume (FV)-based simulation package (OpenFOAM®) to predict the separation initiation using the cohesive zone model (CZM). Atomic force microscopy (AFM)-based retraction curve was used to obtain the separation properties between the biofilm and glass colloid at microscale level, where the CZM parameters were estimated using the Johnson-Kendall-Roberts (JKR) model. In this study CZM is introduced as a reliable method for the investigation of interfacial separation between a biofilm and rigid substrate, in which a high local stress at the interface edge acts as an ultimate stress at the crack tip.This study demonstrated that the total interfacial failure energy measured at the macroscale, was significantly higher than the pure interfacial separation energy obtained by AFM at the microscale, indicating a highly ductile deformation behaviour within the bulk biofilm matrix. The results of this study can significantly contribute to the understanding of biofilm detachments. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

The effect on phase separation of the oxidation state of molybdenum in a Na2O-B2O3-SiO2 glass

International Nuclear Information System (INIS)

Kawamoto, Y.; Clemens, K.; Tomozawa, M.; Warden, J.T.

1981-01-01

The effect of oxidation state on phase separation was studied for 13Na 2 O, 49B 2 O 3 , 38SiO 2 (mol%) glasses containing 1 mol% Mo oxide. The glasses were melted under various conditions to vary the oxidation states of Mo ions. The oxidation states of Mo ions were determined by chemical analysis and ESR. The crystallisation tendency, the immiscibility temperature, and the phase separation morphology of the glasses were examined by DTA, x-ray diffraction, opalescence method, and replica electron microscopy. Glasses containing Mo 4+ ions have a great tendency to precipitate MoO 2 crystals. The immiscibility temperature of glass goes through a minimum when the oxidation states of Mo ions are changed. It was suggested that there is an optimum oxidation state to prevent crystallisation and to suppress the phase separation tendency of this system. (author)

Process, including membrane separation, for separating hydrogen from hydrocarbons

Science.gov (United States)

Baker, Richard W.; Lokhandwala, Kaaeid A.; He, Zhenjie; Pinnau, Ingo

2001-01-01

Processes for providing improved methane removal and hydrogen reuse in reactors, particularly in refineries and petrochemical plants. The improved methane removal is achieved by selective purging, by passing gases in the reactor recycle loop across membranes selective in favor of methane over hydrogen, and capable of exhibiting a methane/hydrogen selectivity of at least about 2.5 under the process conditions.

Study of a dense metal membrane reactor for hydrogen separation from hydroiodic acid decomposition

Energy Technology Data Exchange (ETDEWEB)

Tosti, Silvano; Borelli, Rodolfo; Borgognoni, Fabio [ENEA, Dipartimento FPN, C.R. ENEA Frascati, Via E. Fermi 45, Frascati, Roma I-00044 (Italy); Favuzza, Paolo; Tarquini, Pietro [ENEA, Dipartimento TER, C.R. ENEA Casaccia, Via Anguillarese 301, Roma (Italy); Rizzello, Claudio [Tesi Sas, Via Bolzano 28, Roma (Italy)

2008-10-15

A membrane reactor has been studied for separating the hydrogen produced by the dissociation of hydroiodic acid in the thermochemical-sulfur iodine process. A dense metal membrane tube of wall thickness 0.250 mm has been considered in this analysis for hosting a fixed-bed catalyst: the selective separation of hydrogen from an azeotropic H{sub 2}O-HI mixture has been studied in the temperature range of 700-800 K. The materials being considered for the construction of the membrane tube are niobium and tantalum; as a matter of fact, the most commonly used Pd-Ag membranes cannot withstand the corrosive environment generated by the hydroiodic acid. The Damkohler-Peclet analysis has been used for designing the membrane reactor, while a finite element method has simulated its behaviour: the effect of the temperature and pressure on the HI conversion and hydrogen yield has been evaluated. (author)

Optically transparent, mechanically durable, nanostructured superhydrophobic surfaces enabled by spinodally phase-separated glass thin films.

Science.gov (United States)

Aytug, Tolga; Simpson, John T; Lupini, Andrew R; Trejo, Rosa M; Jellison, Gerald E; Ivanov, Ilia N; Pennycook, Stephen J; Hillesheim, Daniel A; Winter, Kyle O; Christen, David K; Hunter, Scott R; Haynes, J Allen

2013-08-09

We describe the formation and properties of atomically bonded, optical quality, nanostructured thin glass film coatings on glass plates, utilizing phase separation by spinodal decomposition in a sodium borosilicate glass system. Following deposition via magnetron sputtering, thermal processing and differential etching, these coatings are structurally superhydrophilic (i.e., display anti-fogging functionality) and demonstrate robust mechanical properties and superior abrasion resistance. After appropriate chemical surface modification, the surfaces display a stable, non-wetting Cassie-Baxter state and exhibit exceptional superhydrophobic performance, with water droplet contact angles as large as 172°. As an added benefit, in both superhydrophobic and superhydrophilic states these nanostructured surfaces can block ultraviolet radiation and can be engineered to be anti-reflective with broadband and omnidirectional transparency. Thus, the present approach could be tailored toward distinct coatings for numerous markets, such as residential windows, windshields, specialty optics, goggles, electronic and photovoltaic cover glasses, and optical components used throughout the US military.

Optically transparent, mechanically durable, nanostructured superhydrophobic surfaces enabled by spinodally phase-separated glass thin films

Science.gov (United States)

Aytug, Tolga; Simpson, John T.; Lupini, Andrew R.; Trejo, Rosa M.; Jellison, Gerald E.; Ivanov, Ilia N.; Pennycook, Stephen J.; Hillesheim, Daniel A.; Winter, Kyle O.; Christen, David K.; Hunter, Scott R.; Haynes, J. Allen

2013-08-01

We describe the formation and properties of atomically bonded, optical quality, nanostructured thin glass film coatings on glass plates, utilizing phase separation by spinodal decomposition in a sodium borosilicate glass system. Following deposition via magnetron sputtering, thermal processing and differential etching, these coatings are structurally superhydrophilic (i.e., display anti-fogging functionality) and demonstrate robust mechanical properties and superior abrasion resistance. After appropriate chemical surface modification, the surfaces display a stable, non-wetting Cassie-Baxter state and exhibit exceptional superhydrophobic performance, with water droplet contact angles as large as 172°. As an added benefit, in both superhydrophobic and superhydrophilic states these nanostructured surfaces can block ultraviolet radiation and can be engineered to be anti-reflective with broadband and omnidirectional transparency. Thus, the present approach could be tailored toward distinct coatings for numerous markets, such as residential windows, windshields, specialty optics, goggles, electronic and photovoltaic cover glasses, and optical components used throughout the US military.

Optically transparent, mechanically durable, nanostructured superhydrophobic surfaces enabled by spinodally phase-separated glass thin films

International Nuclear Information System (INIS)

Aytug, Tolga; Simpson, John T; Lupini, Andrew R; Trejo, Rosa M; Jellison, Gerald E; Ivanov, Ilia N; Pennycook, Stephen J; Hillesheim, Daniel A; Winter, Kyle O; Christen, David K; Hunter, Scott R; Allen Haynes, J

2013-01-01

We describe the formation and properties of atomically bonded, optical quality, nanostructured thin glass film coatings on glass plates, utilizing phase separation by spinodal decomposition in a sodium borosilicate glass system. Following deposition via magnetron sputtering, thermal processing and differential etching, these coatings are structurally superhydrophilic (i.e., display anti-fogging functionality) and demonstrate robust mechanical properties and superior abrasion resistance. After appropriate chemical surface modification, the surfaces display a stable, non-wetting Cassie–Baxter state and exhibit exceptional superhydrophobic performance, with water droplet contact angles as large as 172°. As an added benefit, in both superhydrophobic and superhydrophilic states these nanostructured surfaces can block ultraviolet radiation and can be engineered to be anti-reflective with broadband and omnidirectional transparency. Thus, the present approach could be tailored toward distinct coatings for numerous markets, such as residential windows, windshields, specialty optics, goggles, electronic and photovoltaic cover glasses, and optical components used throughout the US military. (paper)

FIBER OPTICS: Role of point defects in the photosensitivity of hydrogen-loaded phosphosilicate glass

Science.gov (United States)

Larionov, Yu V.

2010-08-01

It is shown that point defect modifications in hydrogen-loaded phosphosilicate glass (PSG) do not play a central role in determining its photosensitivity. Photochemical reactions that involve a two-step point defect modification and pre-exposure effect are incapable of accounting for photoinduced refractive index changes. It seems likely that a key role in UV-induced refractive index modifications is played by structural changes in the PSG network. Experimental data are presented that demonstrate intricate network rearrangement dynamics during UV exposure of PSG.

Lanthanide-activated Na{sub 5}Gd{sub 9}F{sub 32} nanocrystals precipitated from a borosilicate glass: Phase-separation-controlled crystallization and optical property

Energy Technology Data Exchange (ETDEWEB)

Chen, Daqin, E-mail: dqchen@hdu.edu.cn [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, CAS, Fuzhou 350002 (China); Wan, Zhongyi; Zhou, Yang [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Chen, Yan, E-mail: chenyan@hdu.edu.cn [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Yu, Hua; Lu, Hongwei; Ji, Zhenguo [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Huang, Ping, E-mail: phuang@fjirsm.ac.cn [Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, CAS, Fuzhou 350002 (China)

2015-03-15

Highlights: • Na{sub 5}Gd{sub 9}F{sub 32} nanocrystals embedded glass ceramics were fabricated for the first time. • Such glass ceramics were achieved by phase-separation-controlled crystallization. • Elemental mapping evidenced the segregation of activators into the Na{sub 5}Gd{sub 9}F{sub 32} lattice. • Luminescent color could be tuned by controlling glass crystallization temperature. - Abstract: Lanthanide-activated cubic Na{sub 5}Gd{sub 9}F{sub 32} nanocrystals were precipitated from a borosilicate glass with a specifically designed composition. The precursor glass is already phase-separated after melt-quenching, which is beneficial to the realization of the controllable glass crystallization for affording desirable size, morphology and activator partition. Elemental mapping in the scanning transmission electron microscopy evidenced that the segregation of lanthanide ions into the Na{sub 5}Gd{sub 9}F{sub 32} lattice was in situ formed without the requirement of long-range ionic diffusion. Impressively, such fabricated glass ceramic co-doped with Yb{sup 3+}/Er{sup 3+} ions exhibited intense upconversion luminescence, which was about 500 times higher than that of the precursor glass, and its luminescent color could be easily tuned from red to green by controlling glass crystallization temperature. It is anticipated that such phase-separation synthesis strategy with precise control over nanostructure of glass ceramics offer a great opportunity to design other highly transparent nanocomposites with a wide range of tunable optical properties.

Adaptation of Boynton's mathematical model to hydrogen isotope separation column by cryogenic distillation

International Nuclear Information System (INIS)

Kinoshita, Masahiro; Naruse, Yuji

1981-08-01

Boynton's mathematical simulation procedure for multi-component distillation calculations has the advantage that the Jacobian matrix is calculated analytically. The purpose of the present study is to adapt this procedure to hydrogen isotope separation columns by cryogenic distillation. The Boynton's model is modified so that the model can incorporate decay heat of tritium, nonideality of the hydrogen isotope solutions, multiple feeds and multiple sidestreams. Basic equations are derived and the mathematical simulation procedure is briefly explained. (author)

Development of micro-beam NRA for 3D-mapping of hydrogen distribution in solids: Application of tapered glass capillary to 6 MeV 15N ion

International Nuclear Information System (INIS)

Sekiba, D.; Yonemura, H.; Nebiki, T.; Wilde, M.; Ogura, S.; Yamashita, H.; Matsumoto, M.; Kasagi, J.; Iwamura, Y.; Itoh, T.; Matsuzaki, H.; Narusawa, T.; Fukutani, K.

2008-01-01

A micro-beam NRA system, by means of a resonant nuclear reaction 1 H( 15 N, αγ) 12 C, has been developed for the purpose of the 3D mapping of the hydrogen distribution in solids. To obtain the tens μm size of the beam spot, the combination of the newly proposed tapered glass capillary and a conventional quadrupole magnetic lens is employed. An Y patterned film on a substrate is prepared as an application of the developed system. The 6 MeV 15 N beam focused by glass capillaries down to 50 μm successfully shows the hydrogen distribution. The in-plane NRA profile implies that the beam emitted from the glass capillary outlet is parallel, although the original beam has a considerable divergence. The NRA measurements in the 10 3 Pa N 2 atmosphere due to the low gas conductance of the glass capillary is also demonstrated

Developing methodologies for source attribution. Glass phase separation in Trinitite using NF{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Koeman, Elizabeth C.; Simonetti, Antonio [Notre Dame Univ., IN (United States). Dept. of Civil and Environmental Engineering and Earth Sciences; McNamara, Bruce K.; Smith, Frances N. [Pacific Northwest National Laboratory, Richland, WA (United States). Nuclear Chemistry and Engineering; Burns, Peter C. [Notre Dame Univ., IN (United States). Dept. of Civil and Environmental Engineering and Earth Sciences; Notre Dame Univ., IN (United States). Dept. of Chemistry and Biochemistry

2017-08-01

This study details thermal reactions between glasses, common minerals, and Trinitite post-detonation material with the fluorinating agent nitrogen trifluoride (NF{sub 3}). The ultimate goal of our investigation is to develop a relatively rapid method for the effective separation of bomb components from complex matrices resulting from a nuclear explosion. Trinitite samples, silicate minerals (quartz; plagioclase and microcline), amorphous SiO{sub 2}, calcite, a natural glass (obsidian), and two synthetic glasses were characterized extensively before and after the fluorination to fully understand the effects of the NF{sub 3} thermal treatment. Samples were reacted with NF{sub 3} using a combined thermogravimetric (TG) differential thermal analysis (DTA) unit, as well as in a stainless steel bomb reactor connected to a fluorination line. Subsequent to the NF{sub 3} treatment, samples were imaged by scanning electron microscopy in order to document changes in grain size and morphology. Energy dispersive spectroscopy was performed to determine changes in major element abundances. Results demonstrate that rates of reaction are dependent on grain size, temperature, pressure, and time of fluorination. All mineral samples experienced mass loss during fluorination. Specifically, amorphous SiO{sub 2} (∝90% mass loss) experienced the most while calcite experienced the least (∝18%). Major element analysis reveals that mass loss is attributable to the volatilization of silica (SiO{sub 2}) in Si-bearing phases, or sample decomposition in calcite due to fluorination. Results for fluorinated samples of Trinitite demonstrate that mass loss occurs at different rates for each sample, but each sample experienced an expected large decrease in Si content (resulting from volatilization of SiF{sub 4}). Hence, the concentration of metals in the residual material increased due to the volatilization of Si. These results validate that this thermal-fluorination technique allows the

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

International Nuclear Information System (INIS)

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

1994-01-01

Earlier bench-scale work at the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory examined a number of adsorbents for their suitability for separating low-concentration hydrogen (no tritium) from helium. One of the effective adsorbents was Linde 5A molecular sieve. Recently, experiments including tritium were conducted using practical-scale adsorbers. These tests used existing cryogenic molecular sieve beds (CMSB's) which each contain about 1.6 kg of Linde 5A molecular sieve. They are part of the TSTA integrated tritium processing system. Gas was fed to each CMSB at about 13 SLPM with a nominal composition of 99% He, 0.98% H 2 and 0.02% HT. In all cases, for an extended period of time, the beds allowed no detectable (via Raman spectroscopy) hydrogen isotopes to escape in the bed effluent. Thereafter, the hydrogen isotopes appeared in the bed exit with a relatively sharp breakthrough curve. This work concludes that cryogenic molecular sieve adsorption is an practical and effective means of separating low-concentration hydrogen isotopes from a helium carrier

Studies on the separation of hydrogen isotopes and spin isomers by gas chromatography

International Nuclear Information System (INIS)

Pushpa, K.K.; Annaji Rao, K.

2000-08-01

Separation and analysis of mixture of hydrogen isotopes has gained considerable importance because of various applications needing different isotopes in lasers, nuclear reactions and tracer or labelled compounds. In the literature gas chromatographic methods are reported using columns packed with partly dehydrated or thoroughly dehydrated alumina/molecular sieve stationary phase at 77 deg K with helium, neon and even hydrogen or deuterium as carrier gas. In the present study an attempt is made to compare the chromatographic behaviour of these two stationary phases using virgin and Fe doped form in partly dehydrated and thoroughly dehydrated state, using helium, neon, hydrogen and deuterium as carrier gas. The results of this study show that helium or neon carrier gas behave similarly broad peaks with some tailing. Sharp symmetric peaks are obtained with hydrogen or deuterium carrier gas. This is attributed to large hold up capacity for H 2 or D 2 at 77 deg K in these materials as compared to helium or neon. Spin isomers of H 2 or D 2 are separated on Fe free stationary phases, though ortho H 2 and HD are not resolved. Using a combination of Fe doped short column and plain alumina column, both maintained in dehydrated form, the effect of Fe doping on thermal equilibrium of ortho/para forms at 77 deg K is clearly demonstrated. (author)

Large scale gas chromatographic demonstration system for hydrogen isotope separation

International Nuclear Information System (INIS)

Cheh, C.H.

1988-01-01

A large scale demonstration system was designed for a throughput of 3 mol/day equimolar mixture of H,D, and T. The demonstration system was assembled and an experimental program carried out. This project was funded by Kernforschungszentrum Karlsruhe, Canadian Fusion Fuel Technology Projects and Ontario Hydro Research Division. Several major design innovations were successfully implemented in the demonstration system and are discussed in detail. Many experiments were carried out in the demonstration system to study the performance of the system to separate hydrogen isotopes at high throughput. Various temperature programming schemes were tested, heart-cutting operation was evaluated, and very large (up to 138 NL/injection) samples were separated in the system. The results of the experiments showed that the specially designed column performed well as a chromatographic column and good separation could be achieved even when a 138 NL sample was injected

Influence of Radiation and Multivalent Cation Additions on Phase Separation and Crystallization of Glass

Energy Technology Data Exchange (ETDEWEB)

Michael C. Weinberg; Donald R. Uhlmann; Gary L. Smith

2002-08-09

This report presents results of: (1) measurement of valence state ratios of iron in glass, and (2) a study of the effect of iron redox ratio on phase separation behavior in a glass. The redox ratio of iron in two sodium silicate (NS) glasses has been determined using a colorimetric method, Moessbauer analysis, and optical absorption. The experimental procedures were described in a previous report. We found that these three methods gave excellent agreement for the values of the Fe++/Fe+++ (redox ratio) in the glasses. Also, using the results of the colorimetric analysis we were able to find the extinction coefficients for the18.56% NS and the 13% NS glasses. We have utilized the optical absorption data that was taken for purposes of determining redox ratios to provide glass structural information. In particular, it has been suggested that the band centered near 14,500 cm-1 is indicative of Fe2+ - O2- - Fe3+ formation. In addition, the relative band intensities at 10,000 cm-1 and 4,800 cm-1 could give us information as to the environment around the Fe2+ responsible for the 4,800 cm-1 band. The Moessbauer data will provide supporting structural information. For example, the relative number of clustered and free ferric ions can be computed from the ratio of areas under the doublet and sextet in the liquid He spectra. Also, the change in shift parameter with redox ratio will provide an indication of whether there is an increase or decrease in tetrahedral site symmetry about both ferrous and ferric ions. Finally, the quadrupole splitting parameter provides information regarding the site symmetries about the Fe++ and Fe+++. Currently, we are analyzing the spectral data for these purposes. The Moessbauer work was done in conjunction with colleagues at PNNL, and a manuscript is currently in preparation. The effect of oxidation state of iron on the phase separation of xNa2O {center_dot}(100-x)SiO2 glasses, x = 18.56 and 13, containing 0.5 mole % iron oxide was studied. The

Method for enriching and separating heavy hydrogen isotopes from substance streams containing such isotopes by means of isotope exchange

International Nuclear Information System (INIS)

Knochel, A.; Eggers, I.; Klatte, B.; Wilken, R. D.

1985-01-01

A process for enriching and separating heavy hydrogen isotopes having a heavy hydrogen cation (deuterium and/or tritium) from substance streams containing them, wherein the respectively present hydrogen isotopes are exchanged in chemical equilibria. A protic, acid solution containing deuterium and/or tritium is brought into contact with a value material from the group of open-chained polyethers or aminopolyethers, macro-monocyclic or macro-polycyclic polyethers, macro-monocyclic or macro-polycyclic amino polyethers, and mixtures of these values, in their free or proton salt form to form a reaction product of the heavy hydrogen cation with the value or value salt and bring about enrichment of deuterium and/or tritium in the reaction product. The reaction product containing the value or value salt is separated from the solution. The separated reaction product is treated to release the hydrogen isotope(s) to be enriched in the form of deuterium oxide (HDO) and/or tritium oxide (HTO) by regenerating the value or its salt, respectively. The regenerated value is returned for reuse

Rapid Thermal Annealing and Hydrogen Passivation of Polycrystalline Silicon Thin-Film Solar Cells on Low-Temperature Glass

Directory of Open Access Journals (Sweden)

Mason L. Terry

2007-01-01

Full Text Available The changes in open-circuit voltage (Voc, short-circuit current density (Jsc, and internal quantum efficiency (IQE of aLuminum induced crystallization, ion-assisted deposition (ALICIA polycrystalline silicon thin-film solar cells on low-temperature glass substrates due to rapid thermal anneal (RTA treatment and subsequent remote microwave hydrogen plasma passivation (hydrogenation are examined. Voc improvements from 130 mV to 430 mV, Jsc improvements from 1.2 mA/cm2 to 11.3 mA/cm2, and peak IQE improvements from 16% to > 70% are achieved. A 1-second RTA plateau at 1000°C followed by hydrogenation increases the Jsc by a factor of 5.5. Secondary ion mass spectroscopy measurements are used to determine the concentration profiles of dopants, impurities, and hydrogen. Computer modeling based on simulations of the measured IQE data reveals that the minority carrier lifetime in the absorber region increases by 3 orders of magnitude to about 1 nanosecond (corresponding to a diffusion length of at least 1 μm due to RTA and subsequent hydrogenation. The evaluation of the changes in the quantum efficiency and Voc due to RTA and hydrogenation with computer modeling significantly improves the understanding of the limiting factors to cell performance.

Phase Separation and Crystallization in soda-lime borosilicate glass enriched in MoO{sub 3} studied by in situ Raman spectroscopy at high temperature

Energy Technology Data Exchange (ETDEWEB)

Magnin, M.; Schuller, S.; Advocat, T. [CEA Valrho, DEN/DTCD/SCDV, Laboratoire d' Etude de Base sur les Verres, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Caurant, D.; Majerus, O. [Laboratoire de Chimie de la Matiere Condensee de Paris- LCMCP - UMR-CNRS 7574, Ecole Nationale Superieure de Chimie de Paris - ENSCP, Paristech, 75231 Paris (France); Ligny, D. de [Laboratoire de Physico-Chimie des Materiaux Luminescents- LPCML - UMR-CNRS 5620, Universite Claude Bernard Lyon1, 69622 Villeurbanne (France)

2008-07-01

Phase separation and crystallisation processes may arise in molten glass when the MoO{sub 3} content exceeds its solubility limit. Molybdenum combined with other elements such as alkali and alkaline-earth may form crystalline molybdates, known as 'yellow phases' in nuclear glasses. In order to establish the sequence of phase separation and crystallization processes occurring during the cooling of the melt, a non-radioactive simplified glass composition was chosen in the SiO{sub 2}-B{sub 2}O{sub 3}-Na{sub 2}O-CaO system, with 2 mol.% MoO{sub 3}. Various cooling scenarios were tested: cooling by air blowing, quenching between two copper plates and cooling on metallic plate. The resulting glass specimens were then characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy in temperature. These observations made it possible to determine the sequence and the appearance temperature of phenomena upon cooling: first, a phase separation occurs, (small droplets dispersed in the molten glass) followed by molybdates crystallization inside the droplets. (authors)

The phenomenon of phase separated in Na2O-B2O3-SiO2, Na2O-SiO2-P2O5 glasses

International Nuclear Information System (INIS)

Procyk, B.; Bieniarz, P.; Plichta, E.; Pudelek, B.; Kucinski, G.; Staniewicz-Brudnik, B.

1997-01-01

During the thermal treatment, the phenomenon of phase separation has been observed in the some glasses. The glass has became opaque, due to the opalescence of phase separated. Investigations of the phenomenon of phase separation were conducted using the basic systems: Na 2 O-B 2 O 3 -SiO 2 , Na 2 O-SiO 2 -P 2 O 5 and theirs modifications. The occurrence of binodal and spinodal phase decomposition was observed by TEM. The phase separation inhomogeneities have drop-like character and with higher concentration shows a tendency for coalescence. The influence of the chemical composition, temperature and time on the phenomenon of phase separation in the investigated glasses has been defined. (author)

The influence of column temperature on the hydrogen isotopes separation performance of FDC

International Nuclear Information System (INIS)

Deng Xiaojun; Luo Deli; Qin Cheng; Yang Wan; Huang Guoqiang; Huang Zhiyong

2014-01-01

Frontal displacement chromatography (FDC) is a promising method for hydrogen isotopes separation with obvious advantages such as simple operation process, low tritium retention in system and easy to scale up, etc. We designed and constructed a FDC device using Pd-Al 2 O 3 as separation material in previous study, and the feasibility of FDC for hydrogen isotopes separation was confirmed. On the basis of the results, a series of experiments at different column temperatures were carried out to investigate the temperature influence to the separation performance, with the composition of (5 ± 0.1)% H 2 -(5 ± 0.1)% D 2 -(90 ± 0.1)% Ar of feed gas. Experiments were carried out at the temperature of 303K, 273K, 263K, 253K, 213K, at the gas flow rate of 15 mL (NTP)/min. The results indicated that lower temperature, higher enrichment factor while the feed gas composition and the gas flow rate are definite; lower temperature, shorter 'separation transition state', and then better separation efficiency. The deuterium enrichment factor became 65 from l.5 while the temperature decreased to 273K from 303K. It also showed that the deuterium recovery ratio and the deuterium abundance of product gas increases with the temperature decrease except for the case of 303K. At the temperature of 273K and below, the deuterium recovery ratio were all higher than 42%, deuterium abundance of product were all larger than 98%, and the maximum of deuterium abundance at 213K was 99.8%. (authors)

Application of polymeric foams for separation, storage and absorption of hydrogen

Czech Academy of Sciences Publication Activity Database

Pientka, Zbyněk; Nemestóthy, N.; Bélafi-Bakó, K.

2009-01-01

Roč. 241, 1-3 (2009), s. 106-110 ISSN 0011-9164. [Membrane Science and Technology Conference of Visegrad Countries PERMEA 2007 /3./. Siofok, 02.09.2007-06.09.2007] R&D Projects: GA ČR GA203/06/1207 Institutional research plan: CEZ:AV0Z40500505 Keywords : gas separation * hydrogen * polymeric foam Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.034, year: 2009

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)

Hydrocyclone Separation of Hydrogen Decrepitated NdFeB

Directory of Open Access Journals (Sweden)

Muhammad Awais

2017-11-01

Full Text Available Hydrogen decrepitation (HD is an effective and environmentally friendly technique for recycling of neodymium-iron-boron (NdFeB magnets. During the HD process, the NdFeB breaks down into a matrix phase (Nd2Fe14BHx and RE-rich grain boundary phase. The grain boundary phase in the HD powder is <2 μm in size. Recycled NdFeB material has a higher oxygen content compared to the primary source material. This additional oxygen mainly occurs at the Rare Earth (RE rich grain boundary phase (GBP, because rare earth elements oxidise rapidly when exposed to air. This higher oxygen level in the material results in a drop in density, coercivity, and remanence of sintered NdFeB magnets. The particle size of the GBP is too small to separate by sieving or conventional screening technology. In this work, an attempt has been made to separate the GBP from the matrix phase using a hydrocyclone, and to optimise the separation process. HD powder, obtained from hard disk drive (HDD scrap NdFeB sintered magnets, was used as a starting material and passed through a hydrocyclone a total number of six times. The X-ray fluorescence (XRF analysis and sieve analysis of overflows showed the matrix phase had been directed to the underflow while the GBP was directed to the overflow. The optimum separation was achieved with three passes. Underflow and overflow samples were further analysed using an optical microscope and MagScan and matrix phase particles were found to be magnetic.

Quick analytical separation of glucose and fructose with impregnated woven glass fiber

International Nuclear Information System (INIS)

Jones, S.C.

1978-01-01

(1) A wide separation of glucose and fructose was obtained in 30 min with simple, inexpensive equipment using polysilicic impregnated woven glass fiber and the solvent acetone-n-butanol-1 M H 3 BO 3 (50:40:10). (2) A calibration of a radiochromatogram scanner was performed for 11 C. (3) Three Rsub(F) values could be compared to provide positive chemical identification of [ 11 C]glucose and [ 11 C]fructose. (4) Radiochemical composition and approximate specific activity were determined from a small aliquot (1-4 μl). (Auth.)

Glass science tutorial: Lecture No. 7, Waste glass technology for Hanford

International Nuclear Information System (INIS)

Kruger, A.A.

1995-07-01

This paper presents the details of the waste glass tutorial session that was held to promote knowledge of waste glass technology and how this can be used at the Hanford Reservation. Topics discussed include: glass properties; statistical approach to glass development; processing properties of nuclear waste glass; glass composition and the effects of composition on durability; model comparisons of free energy of hydration; LLW glass structure; glass crystallization; amorphous phase separation; corrosion of refractories and electrodes in waste glass melters; and glass formulation for maximum waste loading

Separation of Th and U using borosilicate glasses

International Nuclear Information System (INIS)

Chandramouleeswaran, S.; Ramkumar, Jayshree; Singhal, R.K.; Reddy, A.V.R.; Sudarsan, V.

2010-01-01

Boroaluminosilicate glasses having B 2 O 3 to Na 2 O ratio 0.23 and 9.8 were prepared by conventional melt-quench method and used as room temperature ion exchanger for the sorption of thorium from aqueous solutions. Various experimental conditions were optimized to achieve selective and maximum uptake of thorium. The studies were extended to synthetic mixtures of thorium and uranium, wherein thorium could be selectively removed in presence of 10 fold excess of uranium. Structural elucidation studies were carried out to understand the ion exchange property of glasses. It is seen that presence of linkages like Si-O - and B-O - in the glasses was responsible for the uptake of metal ions. It is seen that the uptake depends on pH of the solution, composition of glass and the initial concentration of thorium ion in solution. (author)

Modeling the Onset of Phase Separation in CaO-SiO2-CaCl2 Chlorine-Containing Silicate Glasses.

Science.gov (United States)

Swansbury, Laura A; Mountjoy, Gavin; Chen, Xiaojing; Karpukhina, Natalia; Hill, Robert

2017-06-08

The addition of chlorine into a bioactive glass composition is expected to reduce its abrasiveness and increase its bioactivity, which is important for dental applications such as toothpastes. There is a lack of information and understanding regarding the structural role of chlorine in chlorine-containing bioactive silicate glasses. This has prompted classical core-shell model molecular dynamics simulations of (50 - x/2)CaO-(50 - x/2)SiO 2 -xCaCl 2 glasses to be performed, where x ranges from x = 0.0 to 43.1 mol % CaCl 2 . These ternary glasses are advantageous for a fundamental study because they do not have additional network formers (e.g., phosphorus pentoxide) or modifiers (e.g., sodium) typically found in bioactive glass compositions. The (50 - x/2)CaO-(50 - x/2)SiO 2 -xCaCl 2 glasses were seen to become phase-separated around the x = 16.1 mol % CaCl 2 composition, and chlorine predominantly coordinated with calcium. These findings provide a solid foundation for further computational modeling work on more complex chlorine-containing bioactive glass compositions.

NOVEL COMPOSITE MEMBRANES FOR HYDROGEN SEPARATION IN GASIFICATION PROCESSES IN VISION 21 ENERGY PLANTS

Energy Technology Data Exchange (ETDEWEB)

Michael Schwartz

2004-12-01

This report describes the work performed, accomplishments and conclusion obtained from the project entitled ''Novel Composite Membranes for Hydrogen Separation in Gasification Processes in Vision 21 Energy Plants'' under the United States Department of Energy Contract DE-FC26-01NT40973. ITN Energy Systems was the prime contractor. Team members included: the Idaho National Engineering and Environmental Laboratory; Nexant Consulting; Argonne National Laboratory and Praxair. The objective of the program was to develop a novel composite membrane structure for hydrogen separation as a key technology module within the future ''Vision 21'' fossil fuel plants. The separation technology module is targeted for use within the gasification module of the ''Vision 21'' fossil fuel plant. The high performance and low-cost manufacturing of the proposed technology will benefit the deployment of ''Vision 21'' fossil fuel plant processes by improving the energy efficiency, flexibility and environmental performance of these plants. Of particular importance is that this technology will also produce a stream of pure carbon dioxide. This allows facile sequestration or other use of this greenhouse gas. These features will benefit the U.S. in allowing for the continued use of domestic fossil fuels in a more energy efficient and environmentally acceptable manner. The program developed and evaluated composite membranes and catalysts for hydrogen separation. Components of the monolithic modules were fabricated by plasma spray processing. The engineering and economic characteristics of the proposed Ion Conducting Ceramic Membrane (ICCM) approach, including system integration issues, were also assessed. This resulted in a comprehensive evaluation of the technical and economic feasibility of integration schemes of ICCM hydrogen separation technology within Vision 21 fossil fuel plants. Several results and conclusion

Separate effects tests on hydrogen combustion during direct containment heating events

International Nuclear Information System (INIS)

Meyer, L.; Albrecht, G.; Kirstahler, M.; Schwall, M.; Wachter, E.

2008-01-01

In the frame of severe accident research for light water reactors Forschungszentrum Karlsruhe (FZK/IKET) operates the facilities DISCO-C and DISCO-H since 1998, conceived to investigate the direct containment heating (DCH) issue. Previous DCH experiments have investigated the corium dispersion and containment pressurization during DCH in different European reactor geometries using an iron-alumina melt and steam as model fluids. The analysis of these experiments showed that the containment was pressurized by the debris-to-gas heat transfer but also to a large part by hydrogen combustion. The need was identified to better characterize the hydrogen combustion during DCH. To address this issue separate effect tests in the DISCO-H facility were conducted. These tests reproduced phenomena occurring during DCH (injection of a hot steam-hydrogen mixture jet into the containment and ignition of the air-steam-hydrogen mixture) with the exception of corium dispersion. The effect of corium particles as igniters was simulated using sparkler systems. The data will be used to validate models in combustion codes and to extrapolate to prototypic scale. Tests have been conducted in the DISCO-H facility in two steps. First a small series of six tests was done in a simplified geometry to study fundamental parameters. Then, two tests were done with a containment geometry subdivided into a subcompartment and the containment dome. The test conditions were as follows: As initial condition in the containment an atmosphere was used either with air or with a homogeneous air-steam mixture containing hydrogen concentrations between 0 and 7 mol%, temperatures around 100 C and pressure at 2 bar (representative of the containment atmosphere conditions at vessel failure). Injection of a hot steam-hydrogen jet mixture into the reactor cavity pit at 20 bar, representative of the primary circuit blow down through the vessel and hydrogen produced during this phase. The most important variables

A design study of hydrogen isotope separation system for ITER-FEAT

International Nuclear Information System (INIS)

Iwai, Yasunori; Yamanishi, Toshihiko; Nishi, Masataka

2001-03-01

Preliminary design study of the hydrogen isotope separation system (ISS) for the fuel cycle of the ITER-FEAT, a fusion experimental reactor, was carried out based on the substantial reduction of hydrogen flow to the ISS resulting from the design study for scale reduction of the formerly-designed ITER. Three feed streams (plasma exhaust gas stream, streams from the water detritiation system and that from the neutral beam injectors) are fed to the ISS, and three product streams (high purity tritium gas, high purity deuterium gas and hydrogen gas) are made in it by the method of cryogenic distillation. In this study, an original four-column cascade was proposed to the ISS cryogenic distillation column system considering simplification and the operation scenario of the ITER-FEAT. Substantial reduction of tritium inventory in the ISS was found to be possible in the progress of investigation concerning of the corresponding flow rate of tritium product stream (T>90 %) for pellet injector which depends upon the operation condition. And it was found that tritium concentration in the released hydrogen stream into environment from the ISS could easily fluctuate with current design of column arrangement due to the small disturbance in mass flow balance in the ISS. To solve this problem, two-column system for treatment of this flow was proposed. (author)

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

Metallic Membranes for High Temperature Hydrogen Separation

DEFF Research Database (Denmark)

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

2013-01-01

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

Derivation of basic equations for rigorous dynamic simulation of cryogenic distillation column for hydrogen isotope separation

International Nuclear Information System (INIS)

Kinoshita, Masahiro; Naruse, Yuji

1981-08-01

The basic equations are derived for rigorous dynamic simulation of cryogenic distillation columns for hydrogen isotope separation. The model accounts for such factors as differences in latent heat of vaporization among the six isotopic species of molecular hydrogen, decay heat of tritium, heat transfer through the column wall and nonideality of the solutions. Provision is also made for simulation of columns with multiple feeds and multiple sidestreams. (author)

Research and development on is process components for hydrogen production. (2) Corrosion resistance of glass lining in high temperature sulfuric acid

International Nuclear Information System (INIS)

Tanaka, Nobuyuki; Iwatsuki, Jin; Kubo, Shinji; Terada, Atsuhiko; Onuki, Kaoru

2009-01-01

Japan Atomic Energy Agency has been conducting a research and development on hydrogen production system using High Temperature Gas-Cooled Reactor. As a part of this effort, thermochemical water-splitting cycle featuring iodine- and sulfur-compounds (IS process) is under development considering its potential of large-scale economical hydrogen production. The IS process constitutes very severe environments on the materials of construction because of the corrosive nature of process chemicals, especially of the high temperature acidic solution of sulfuric acid and hydriodic acid dissolving iodine. Therefore, selection of the corrosion-resistant materials and development of the components has been studied as a crucial subject of the process development. This paper discusses corrosion resistance of commercially available glass-lining material in high temperature sulfuric acid. Corrosion resistance of a soda glass used for glass-lining was examined by immersion tests. The experiments were performed in 47-90wt% sulfuric acids at temperatures of up to 400degC and for the maximum immersion time of 100 hours using an autoclave designed for the concerned tests. In every condition tested, no indication of localized corrosion such as defect formation or pitting corrosion was observed. Also, the corrosion rates decreased with the progress of immersion, and were low enough (≅0.1 mm/year) after 60-90 hours of immersion probably due to formation of a silica rich surface. (author)

Hydrogen Silsesquioxane based silica glass coatings for the corrosion protection of austenitic stainless steel

DEFF Research Database (Denmark)

Lampert, Felix; Jensen, Annemette Hindhede; Din, Rameez Ud

2016-01-01

-film barrier coatings were deposited on AISI 316L grade austenitic stainless steel with 2B surface finish from Hydrogen Silsesquioxane (HSQ) spin-on-glass precursor and thermally cured to tailor the film properties. Results showed that curing at 500 °C resulted in a film-structure with a polymerized siloxane...... backbone and a reduced amount of Si-H moieties. The coatings showed good substrate coverage and the average thickness was between 200 and 400 nm on the rough substrate surface, however, film thicknesses of > 1400 nm were observed at substrate defects. Deposition of these films significantly improved...... the barrier-properties by showing a 1000 times higher modulus while an ionic transport over the coating was also observed....

Modified molecular sieves: stationary phase for the gas chromatographic separation of hydrogen isotopes

International Nuclear Information System (INIS)

Pushpa, K.K.; Annaji Rao, K.; Iyer, R.M.

1993-01-01

Gas chromatographic separation of hydrogen isotopes on different molecular sieves at liquid nitrogen temperature has been investigated. Normal molecular sieves 5A, 13X and AW500 are not satisfactory for the purpose both in the partially dehydrated as well as totally dehydrated state. Molecular sieve 4A in partially dehydrated state separated H 2 and D 2 while H 2 and HD are not well resolved. Iron exchanged or coated molecular sieves 4A, 5A, 13X and AW500 in the partially dehydrated state separated the isotopic mixtures H 2 , HD, D 2 and H 2 , HT, T 2 . The resolution varied depending on the amount of iron content and the residual moisture in the molecular sieves. Good separations were obtained on 15% Fe coated molecular sieve 5A and 5% Fe coated molecular sieve 4A. (author). 18 refs., 6 figs., 3 tabs

Phase separation, clustering, and fractal characteristics in glass: A magic-angle-spinning NMR spin-lattice relaxation study

Science.gov (United States)

Sen, S.; Stebbins, J. F.

1994-07-01

A comparative study of the 29Si spin-lattice relaxation behavior (induced by trace amounts of paramagnetic dopants in the glass) in phase-separated Li2Si4O9 and monophasic Li2Si2O5 and Na2Si2O5 glasses has been made in order to understand the nature of clustering and the resulting intermediate-range ordering. Optically clear tetrasilicate and disilicate glasses were prepared with 500 to 2000 ppm of Gd2O3, a paramagnetic dopant. The constituent structural units (Q3 and Q4 species) in all tetrasilicate glasses show strong differential relaxation following a power-law behavior. This is due to preferential partitioning of Gd3+ into the lower silica (Q3-rich) regions of these glasses, indicating the presence of Q species clusters too small to produce optical opalescence (a few nm to perhaps tens of nm). Preliminary results on 6Li spin-lattice relaxation in these glasses support this hypothesis. Differential relaxation becomes more pronounced on annealing due to growth of such clusters. No such differential relaxation was observed in the monophase disilicate glasses. For spin-lattice relaxation induced by direct dipolar coupling to paramagnetic ions, the recovery of magnetization is proportional to time as M(t)~tα where α is a function of the dimensionality D of mass distribution of the constituent Q species around the Gd3+ paramagnetic centers in the glass. For tetrasilicate glasses D~=2.62+/-0.22 and the system behaves as a mass fractal up to a length scale of 2 to 3 nm. D is thus equal to, within error, the theoretical value of 2.6 for an infinite percolation cluster of one type of Q species in another. For disilicate glasses, D~=3.06+/-0.18 which indicates a three-dimensional (and thus nonfractal) mass distribution of the constituent Q species over the same length scale.

Heterogeneously catalyzed deuterium separation processes: Hydrogen-water exchange studies at elevated temperatures and pressures

International Nuclear Information System (INIS)

Halliday, J.D.; Rolston, J.H.; Au, J.C.; Den Hartog, J.; Tremblay, R.R.

1985-01-01

New processes for the separation of hydrogen isotopes are required to produce heavy water for CANDU nuclear reactors and to extract tritium formed in the moderator during reactor operation. Wetproofed platinum catalysts capable of promoting rapid exchange of isotopes between countercurrent flows of hydrogen and liquid water in packed columns have been developed at CRNL over the past 15 years. These catalysts provide a catalystic surface for the gas phase exchange reaction H/sub 2/O/sub (v)/ + HD/sub (g)/ ↔ HDO/sub (v)/ + H/sub 2(g)/ as well as a large liquid surface for the liquid phase isotope transfer reaction HDO/sub (v)/ + H/sub 2/O/sub (iota)/↔HDO/sub (iota)/+H/sub 2/O/sub (v)/. Any economic stand-alone heavy water separation process, based on bithermal hydrogen-water exchange over wetproofed platinum catalysts, requires rapid overall exchange of isotopes between two phases at two temperatures. Catalysts developed for cold tower operation at 25-60 0 C are now being tested in a laboratory scale stainless steel trickle bed reactor for performance and stability at simulated hot tower conditions, 150 0 C and 2.0 MPa pressure. Catalytically active layers containing platinum supported on carbon or crystalline silica and wetproofed with Teflon have been prepared on ceramic spheres and stainless steel screening and tested in both random and ordered bed columns

Mass and heat transfer on B7 structured packing in the separation of hydrogen isotopes by distillation

International Nuclear Information System (INIS)

Croitoru, C.; Pop, F.; Titescu, Gh.; Culcer, M.; Iliescu, M.; Stefanescu, I.; Trancota, D.; Peculea, M.

2002-01-01

The paper presents theoretical and experimental data concerning mass and heat transfer on B7 ordered packing, at deuterium separation by distillation. The first section of the paper is dedicated to the mass transfer study of hydrogen distillation, while the second section deals with mass and heat transfer in water distillation. A mathematical model was worked out and compared with experimental data, obtained from two laboratory distillation plants for deuterium separation. From the first plant experimental data concerning B7 ordered packing efficiency of hydrogen cryogenic distillation at 250 deg. C level were obtained. Data concerning mass and heat transfer on the same packing in deuterium separation by water vacuum distillation at 60 deg. C level were obtained in the second plant. HUT values, mass and heat transfer coefficients both theoretically evaluated and experimentally determined were found to be comparable with those obtained from chemical industry separation processes. The fact justifies the use of multi-tubular column model for description of transfer processes in distillation columns equipped with B7 structured packing. (authors)

Neutron transmission measurements on hydrogen filled microspheres

International Nuclear Information System (INIS)

Dyrnjaja, Eva; Hummel, Stefan; Keding, Marcus; Smolle, Marie-Theres; Gerger, Joachim; Zawisky, Michael

2014-01-01

Hollow microspheres are promising candidates for future hydrogen storage technologies. Although the physical process for hydrogen diffusion through glass is well understood, measurements of static quantities (e.q. hydrogen pressure inside the spheres) as well as dynamic properties (e.g. diffusion rate of hydrogen through glass) are still difficult to handle due to the small size of the spheres (d≈15μm). For diffusion rate measurements, the long-term stability of the experiment is also mandatory due to the relatively slow diffusion rate. In this work, we present an accurate and long-term stable measurement technique for static and dynamic properties, using neutron radiography. Furthermore, possible applications for hydrogen filled microspheres within the scope of radiation issues are discussed

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

Hydrogen gas detector

International Nuclear Information System (INIS)

Bohl, T.L.

1982-01-01

A differential thermocouple hydrogen gas detector has one thermocouple junction coated with an activated palladium or palladium-silver alloy catalytic material to allow heated hydrogen gas to react with the catalyst and raise the temperature of that junction. The other juction is covered with inert glass or epoxy resin, and does not experience a rise in temperature in the presence of hydrogen gas. A coil heater may be mounted around the thermocouple junctions to heat the hydrogen, or the gas may be passed through a heated block prior to exposing it to the thermocouples

High temperature cathodic charging of hydrogen in zirconium alloys and iron and nickel base alloys

International Nuclear Information System (INIS)

John, J.T.; De, P.K.; Gadiyar, H.S.

1990-01-01

These investigations lead to the development of a new technique for charging hydrogen into metals and alloys. In this technique a mixture of sulfates and bisulfates of sodium and potassium is kept saturated with water at 250-300degC in an open pyrex glass beaker and electrolysed using platinum anode and the material to be charged as the cathode. Most of the studies were carried out on Zr alloys. It is shown that because of the high hydrogen flux available at the surface and the high diffusivity of hydrogen in metals at these temperatures the materials pick up hydrogen faster and more uniformly than the conventional electrolytic charging at room temperature and high temperature autoclaving in LiOH solutions. Chemical analysis, metallographic examination and XRD studies confirm this. This technique has been used to charge hydrogen into many iron and nickel base austentic alloys, which are very resistant to hydrogen pick up and to H-embrittlement. Since this involved a novel method of electrolysing water, the hydrogen/deuterium isotopic ratio has been studied. At this temperatures the D/H ratio in the evolved hydrogen gas was found to be closer to the value in the liquid water, which means a smaller separation factor. This confirm the earlier observation that separation factor decreases with increase of temperature. (author). 16 refs., 21 fi gs., 6 tabs

STRUCTURAL INTERACTIONS OF HYDROGEN WITH BULK AMORPHOUS MICROSTRUCTURES IN METALLIC SYSTEMS UNDERSTANDING THE ROLE OF PARTIAL CRYSTALLINITY ON PERMEATION AND EMBRITTLEMENT

Energy Technology Data Exchange (ETDEWEB)

Brinkman, Kyle; Fox, Elise; Korinko, Paul; Adams, Thad

2010-05-10

The development of metallic glasses in bulk form has led to a resurgence of interest into the utilization of these materials for a variety of applications. A potentially exciting application for these bulk metallic glass (BMG) materials is their use as composite membranes to replace high cost Pd/Pd-alloy membranes for enhanced gas separation processes. One of the major drawbacks to the industrial use of Pd/Pd-alloy membranes is that during cycling above and below a critical temperature an irreversible change takes place in the palladium lattice structure which can result in significant damage to the membrane. Furthermore, the cost associated with Pd-based membranes is a potential detractor for their continued use and BMG alloys offer a potentially attractive alternative. Several BMG alloys have been shown to possess high permeation rates, comparable to those measured for pure Pd metal. In addition, high strength and toughness when either in-situ or ex-situ second phase dispersoids are present. Both of these properties, high permeation and high strength/toughness, potentially make these materials attractive for gas separation membranes that could resist hydrogen 'embrittlement'. However, a fundamental understanding of the relationship between partially crystalline 'structure'/devitrification and permeation/embrittlement in these BMG materials is required in order to determine the operating window for separation membranes and provide additional input to the material synthesis community for improved alloy design. This project aims to fill the knowledge gap regarding the impact of crystallization on the permeation properties of metallic glass materials. The objectives of this study are to (i) determine the crystallization behavior in different gas environments of Fe and Zr based commercially available bulk metallic glass and (ii) quantify the effects of partial crystallinity on the hydrogen permeation properties of these metallic glass membranes.

Investigation related to hydrogen isotopes separation by cryogenic distillation

International Nuclear Information System (INIS)

Bornea, A.; Zamfirache, M.; Stefanescu, I.; Preda, A.; Balteanu, O.; Stefan, I.

2008-01-01

Research conducted in the last fifty years has shown that one of the most efficient techniques of removing tritium from the heavy water used as moderator and coolant in CANDU reactors (as that operated at Cernavoda (Romania)) is hydrogen cryogenic distillation. Designing and implementing the concept of cryogenic distillation columns require experiments to be conducted as well as computer simulations. Particularly, computer simulations are of great importance when designing and evaluating the performances of a column or a series of columns. Experimental data collected from laboratory work will be used as input for computer simulations run at larger scale (for The Pilot Plant for Tritium and Deuterium Separation) in order to increase the confidence in the simulated results. Studies carried out were focused on the following: - Quantitative analyses of important parameters such as the number of theoretical plates, inlet area, reflux flow, flow-rates extraction, working pressure, etc. - Columns connected in series in such a way to fulfil the separation requirements. Experiments were carried out on a laboratory-scale installation to investigate the performance of contact elements with continuous packing. The packing was manufactured in our institute. (authors)

The use of nylon and glass fiber filter separators with different pore sizes in air-cathode single-chamber microbial fuel cells

KAUST Repository

Zhang, Xiaoyuan

2010-01-01

Separators are needed in microbial fuel cells (MFCs) to reduce electrode spacing and preventing electrode short circuiting. The use of nylon and glass fiber filter separators in single-chamber, air-cathode MFCs was examined for their effect on performance. Larger pore nylon mesh were used that had regular mesh weaves with pores ranging from 10 to 160 μm, while smaller pore-size nylon filters (0.2-0.45 μm) and glass fiber filters (0.7-2.0 μm) had a more random structure. The pore size of both types of nylon filters had a direct and predictable effect on power production, with power increasing from 443 ± 27 to 650 ± 7 mW m-2 for pore sizes of 0.2 and 0.45 μm, and from 769 ± 65 to 941 ± 47 mW m-2 for 10 to 160 μm. In contrast, changes in pore sizes of the glass fiber filters resulted in a relatively narrow change in power (732 ± 48 to 779 ± 43 mW m-2) for pore sizes of 0.7 to 2 μm. An ideal separator should increase both power density and Coulombic efficiency (CE). However, CEs measured for the different separators were inversely correlated with power production, demonstrating that materials which reduced the oxygen diffusion into the reactor also hindered proton transport to the cathode, reducing power production through increased internal resistance. Our results highlight the need to develop separators that control oxygen transfer and facilitate proton transfer to the cathode. © 2010 The Royal Society of Chemistry.

MoO3 incorporation in magnesium aluminosilicate glasses

International Nuclear Information System (INIS)

Tan, Shengheng; Ojovan, Michael I.; Hyatt, Neil C.; Hand, Russell J.

2015-01-01

Molybdate has a very low solubility in silicate and borosilicate glass systems and its excess presence in nuclear waste glass can cause the formation of a readily soluble “yellow phase”. In this study, the incorporation of molybdenum oxide (MoO 3 ) in a magnesium aluminosilicate glass system has been investigated. The prepared glasses show a higher than 90% molybdenum retention rate and up to 5.34 mol% (12.28 wt%) MoO 3 can be incorporated into these glasses without causing visible phase separation. The incorporation of MoO 3 increases glass density, decreases glass transition and crystallisation temperatures and intensifies Raman bands assigned to vibrations of MoO 4 2− units. When excess molybdate is added liquid–liquid phase separation and crystallisation occurs. The separated phase is spherical, 200–400 nm in diameter and randomly dispersed. Based on powder X-ray diffraction, Raman spectroscopy and transmission electron microscopy, the separated phase is identified as MgMoO 4

Differential saturation study of radial and angular modulation mechanisms of electron spin--lattice relaxation for trapped hydrogen atoms in sulfuric acid glasses. [X radiation

Energy Technology Data Exchange (ETDEWEB)

Plonka, A; Kevan, L

1976-11-01

A differential ESR saturation study of allowed transitions and forbidden proton spin-flip satellite transitions for trapped hydrogen atoms in sulfuric acid glasses indicates that angular modulation dominates the spin-lattice relaxation mechanisms and suggests that the modulation arises from motion of the H atom.

Advanced Palladium Membrane Scale-up for Hydrogen Separation

Energy Technology Data Exchange (ETDEWEB)

Emerson, Sean; Magdefrau, Neal; She, Ying; Thibaud-Erkey, Catherine

2012-10-31

The main objective of this project was to construct, test, and demonstrate a Pd-Cu metallic tubular membrane micro-channel separator capable of producing 2 lb day{sup -1} H{sub 2} at 95% recovery when operating downstream of an actual coal gasifier. A key milestone for the project was to complete a pilot-scale gasifier test by 1 September 2011 and demonstrate the separation of 2 lb day{sup -1} H{sub 2} to verify progress toward the DOE's goals prior to down-selection for larger-scale (100 lb day{sup -1}) hydrogen separator development. Three different pilot-scale (1.5 ft{sup 2}) separators were evaluated downstream of coal gasifiers during four different tests and the key project milestone was achieved in August 2011, ahead of schedule. During three of those tests, all of the separators demonstrated or exceeded the targeted separation rate of 2 lb day{sup -1} H{sub 2}. The separator design was proved to be leak tight and durable in the presence of gasifier exhaust contaminants at temperatures and pressures up to 500 °C and 500 psia. The contaminants in the coal gasifier syngas for the most part had negligible impact on separator performance, with H{sub 2} partial pressure being the greatest determinant of membrane performance. Carbon monoxide and low levels of H{sub 2}S (<39 ppmv) had no effect on H{sub 2} permeability, in agreement with laboratory experiments. However, higher levels of H{sub 2}S (>100 ppmv) were shown to significantly reduce H{sub 2} separation performance. The presence of trace metals, including mercury and arsenic, appeared to have no effect based on the experimental data. Subscale Pd-Cu coupon tests further quantified the impact of H{sub 2}S on irreversible sulfide formation in the UTRC separators. Conditions that have a thermodynamic driving force to form coke were found to reduce the performance of the separators, presumably by blockage of effective separation area with carbon deposits. However, it was demonstrated that both in situ

Mass and heat transfer on B7 ordered packing in hydrogen isotope separation by distillation

International Nuclear Information System (INIS)

Croitoru, Cornelia; Pop, Floarea; Titescu, Gheorghe; Stefanescu, Ioan; Trancota, Dan; Peculea, Marius

2002-01-01

This work presents theoretical and experimental data referring to mass and heat transfer on B7 ordered packing in deuterium isotope separation by distillation. The first part is devoted to the study of mass transfer in hydrogen isotopic distillation while the second one treats the mass and heat transfer in water isotopic distillation. A stationary mathematical model for the mass and heat transfer was developed based on multitubular column model with wet wall. This model allowed the calculation starting from theoretical data of the ordered packing efficiency, expressed by the transfer unit height, TUH. Also, from theoretical data the mass and heat transfer coefficients were determined. A test of the mathematical model was performed with the experimental data obtained from two laboratory installations for hydrogen isotope separation by distillation. From the first installation, experimental data concerning the B7 ordered packing efficiency were obtained for the deuterium separation by cryogenic distillation at the - 250 deg C level. With the second one data referring to the mass and heat transfer on the same packing were obtained for the deuterium separation by water distillation under vacuum at the 60 deg C level. The values of TUH, mass and heat transfer coefficients as theoretically evaluate and experimentally checked are in agreement with the respective values obtained in separation processes in chemical industry. This is the fact which endorses utilization of the model of multitubular column with wet wall for describing the transfer processes in distillation columns equipped with B7 ordered packing

Diffusion characteristics of specific metals at the high temperature hydrogen separation; Diffusionseigenschaften bestimmter Metalle bei der Hochtemperatur-Wasserstoffabtrennung

Energy Technology Data Exchange (ETDEWEB)

Schaefer, Christian

2010-09-07

This paper evaluates the metals palladium, nickel, niobium, tantalum, titanium and vanadium according to their ability to separate hydrogen at high temperatures. This evaluation is chiefly based on a thorough consideration of the properties of diffusion for these metals. The various known hydrogen permeabilities of the metals in a temperature range from 300 to 800 C, as well as their physical and mechanical properties will be presented consistent with the current state of technology. The theory of hydrogen diffusion in metals and the mathematical basis for the calculation of diffusion will also be shown. In the empirical section of the paper, permeability measurements are taken in a temperature range of 400 to 825 C. After measurement, the formation of the oxide coating on these membranes is examined using a light-optical microscope. The results of these examinations allow a direct comparison of the different permeabilities of the various metals within the temperature range tested, and also allow for a critical evaluation of the oxide coating formed on the membranes. The final part of the paper shows the efficiency of these metals in the context of in-situ hydrogen separation in a biomass reformer. (orig.)

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

Energy Technology Data Exchange (ETDEWEB)

Way, J. Douglas [Colorado School of Mines, Golden, CO (United States). Dept. of Chemical and Biological Engineering; Wolden, Colin A. [Colorado School of Mines, Golden, CO (United States)

2013-09-30

Colorado School of Mines (CSM) developed high temperature, hydrogen permeable membranes that contain no platinum group metals with the goal of separating hydrogen from gas mixtures representative of gasification of carbon feedstocks such as coal or biomass in order to meet DOE NETL 2015 hydrogen membrane performance targets. We employed a dual synthesis strategy centered on transition metal carbides. In the first approach, novel, high temperature, surface diffusion membranes based on nanoporous Mo₂C were fabricated on ceramic supports. These were produced in a two step process that consisted of molybdenum oxide deposition followed by thermal carburization. Our best Mo₂C surface diffusion membrane achieved a pure hydrogen flux of 367 SCFH/ft² at a feed pressure of only 20 psig. The highest H₂/N₂ selectivity obtained with this approach was 4.9. A transport model using “dusty gas” theory was derived to describe the hydrogen transport in the Mo₂C coated, surface diffusion membranes. The second class of membranes developed were dense metal foils of BCC metals such as vanadium coated with thin (< 60 nm) Mo₂C catalyst layers. We have fabricated a Mo₂C/V composite membrane that in pure gas testing delivered a H₂ flux of 238 SCFH/ft² at 600 °C and 100 psig, with no detectable He permeance. This exceeds the 2010 DOE Target flux. This flux is 2.8 times that of pure Pd at the same membrane thickness and test conditions and over 79% of the 2015 flux target. In mixed gas testing we achieved a permeate purity of ≥99.99%, satisfying the permeate purity milestone, but the hydrogen permeance was low, ~0.2 SCFH/ft².psi. However, during testing of a Mo₂C coated Pd alloy membrane with DOE 1 feed gas mixture a hydrogen permeance of >2 SCFH/ft².psi was obtained which was stable during the entire test, meeting the permeance associated with

Unraveling the interplay between hydrogen bonding and rotational energy barrier to fine-tune the properties of triazine molecular glasses.

Science.gov (United States)

Laventure, Audrey; De Grandpré, Guillaume; Soldera, Armand; Lebel, Olivier; Pellerin, Christian

2016-01-21

Mexylaminotriazine derivatives form molecular glasses with outstanding glass-forming ability (GFA), high resistance to crystallization (glass kinetic stability, GS), and a glass transition temperature (Tg) above room temperature that can be conveniently modulated by selection of the headgroup and ancillary groups. A common feature of all these compounds is their secondary amino linkers, suggesting that they play a critical role in their GFA and GS for reasons that remain unclear because they can simultaneously form hydrogen (H) bonds and lead to a high interconversion energy barrier between different rotamers. To investigate independently and better control the influence of H bonding capability and rotational energy barrier on Tg, GFA and GS, a library of twelve analogous molecules was synthesized with different combinations of NH, NMe and O linkers. Differential scanning calorimetry (DSC) revealed that these compounds form, with a single exception, kinetically stable glasses with Tg values spanning a very broad range from -25 to 94 °C. While variable temperature infrared spectroscopy combined to chemometrics reveals that, on average, around 60% of the NH groups are still H-bonded as high as 40 °C above Tg, critical cooling rates obtained by DSC clearly show that molecules without H-bond donating linkers also present an outstanding GFA, meaning that H bonding plays a dominant role in controlling Tg but is not required to prevent crystallization. It is a high interconversion energy barrier, provoking a distribution of rotamers, that most efficiently promotes both GFA and resistance to crystallization. These new insights pave the way to more efficient glass engineering by extending the possible range of accessible Tg, allowing in particular the preparation of homologous glass-formers with high GS at ambient temperature in either the viscous or vitreous state.

A high stability Ni-La0.5Ce0.5O2-δ asymmetrical metal-ceramic membrane for hydrogen separation and generation

Science.gov (United States)

Zhu, Zhiwen; Sun, Wenping; Wang, Zhongtao; Cao, Jiafeng; Dong, Yingchao; Liu, Wei

2015-05-01

In this work, hydrogen permeation properties of Ni-La0.5Ce0.5O2-δ (LDC) asymmetrical cermet membrane are investigated, including hydrogen fluxes (JH2) under different hydrogen partial pressures, the influence of water vapor on JH2 and the long-term stability of the membrane operating under the containing-CO2 atmosphere. Ni-LDC asymmetrical membrane shows the best hydrogen permeability among LDC-based hydrogen separation membranes, inferior to Ni-BaZr0.1Ce0.7Y0.2O3-δ asymmetrical membrane. The water vapor in feed gas is beneficial to hydrogen transport process, which promote an increase of JH2 from 5.64 × 10-8 to 6.83 × 10-8 mol cm-2 s-1 at 900 °C. Stability testing of hydrogen permeation suggests that Ni-LDC membrane remains stable against CO2. A dual function of combining hydrogen separation and generation can be realized by humidifying the sweep gas and enhance the hydrogen output by 1.0-1.5 times. Ni-LDC membrane exhibits desirable performance and durability in dual-function mode. Morphologies and phase structures of the membrane after tests are also characterized by SEM and XRD.

SEPARATION OF HYDROGEN AND CARBON DIOXIDE USING A NOVEL MEMBRANE REACTOR IN ADVANCED FOSSIL ENERGY CONVERSION PROCESS

Energy Technology Data Exchange (ETDEWEB)

Shamsuddin Ilias

2005-02-03

Inorganic membrane reactors offer the possibility of combining reaction and separation in a single operation at high temperatures to overcome the equilibrium limitations experienced in conventional reactor configurations. Such attractive features can be advantageously utilized in a number of potential commercial opportunities, which include dehydrogenation, hydrogenation, oxidative dehydrogenation, oxidation and catalytic decomposition reactions. However, to be cost effective, significant technological advances and improvements will be required to solve several key issues which include: (a) permselective thin solid film, (b) thermal, chemical and mechanical stability of the film at high temperatures, and (c) reactor engineering and module development in relation to the development of effective seals at high temperature and high pressure. In this project, we are working on the development and application of palladium and palladium-silver alloy thin-film composite membranes in membrane reactor-separator configuration for simultaneous production and separation of hydrogen and carbon dioxide at high temperature. From our research on Pd-composite membrane, we have demonstrated that the new membrane has significantly higher hydrogen flux with very high perm-selectivity than any of the membranes commercially available. The steam reforming of methane by equilibrium shift in Pd-composite membrane reactor is being studied to demonstrate the potential application of this new development. A two-dimensional, pseudo-homogeneous membrane-reactor model was developed to investigate the steam-methane reforming (SMR) reactions in a Pd-based membrane reactor. Radial diffusion was taken into consideration to account for the concentration gradient in the radial direction due to hydrogen permeation through the membrane. With appropriate reaction rate expressions, a set of partial differential equations was derived using the continuity equation for the reaction system. The equations were

Proceedings of the national conference on functional glasses/glass-ceramics and ceramics: souvenir

International Nuclear Information System (INIS)

2015-01-01

This conference deals with issues relevant to functional glasses and glass ceramics which are technologically important materials for lasers, radioactive waste immobilization, radiation shielding, bio-glasses etc. It covers wide range of subjects and their applications right from managing the side effects of nuclear wastes and shielding the radiation, to sol-gel based bio-glass and its composites. Papers relevant to INIS are indexed separately

System efficiency for two-step metal oxide solar thermochemical hydrogen production – Part 2: Impact of gas heat recuperation and separation temperatures

KAUST Repository

Ehrhart, Brian D.

2016-09-22

The solar-to-hydrogen (STH) efficiency is calculated for various operating conditions for a two-step metal oxide solar thermochemical hydrogen production cycle using cerium(IV) oxide. An inert sweep gas was considered as the O2 removal method. Gas and solid heat recuperation effectiveness values were varied between 0 and 100% in order to determine the limits of the effect of these parameters. The temperature at which the inert gas is separated from oxygen for an open-loop and recycled system is varied. The hydrogen and water separation temperature was also varied and the effect on STH efficiency quantified. This study shows that gas heat recuperation is critical for high efficiency cycles, especially at conditions that require high steam and inert gas flowrates. A key area for future study is identified to be the development of ceramic heat exchangers for high temperature gas-gas heat exchange. Solid heat recuperation is more important at lower oxidation temperatures that favor temperature-swing redox processing, and the relative impact of this heat recuperation is muted if the heat can be used elsewhere in the system. A high separation temperature for the recycled inert gas has been shown to be beneficial, especially for cases of lower gas heat recuperation and increased inert gas flowrates. A higher water/hydrogen separation temperature is beneficial for most gas heat recuperation effectiveness values, though the overall impact on optimal system efficiency is relatively small for the values considered. © 2016 Hydrogen Energy Publications LLC.

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.

Highly hydrothermally stable microporous silica membranes for hydrogen separation.

Science.gov (United States)

Wei, Qi; Wang, Fei; Nie, Zuo-Ren; Song, Chun-Lin; Wang, Yan-Li; Li, Qun-Yan

2008-08-07

Fluorocarbon-modified silica membranes were deposited on gamma-Al2O3/alpha-Al2O3 supports by the sol-gel technique for hydrogen separation. The hydrophobic property, pore structure, gas transport and separation performance, and hydrothermal stability of the modified membranes were investigated. It is observed that the water contact angle increases from 27.2+/-1.5 degrees for the pure silica membranes to 115.0+/-1.2 degrees for the modified ones with a (trifluoropropyl)triethoxysilane (TFPTES)/tetraethyl orthosilicate (TEOS) molar ratio of 0.6. The modified membranes preserve a microporous structure with a micropore volume of 0.14 cm3/g and a pore size of approximately 0.5 nm. A single gas permeation of H2 and CO2 through the modified membranes presents small positive apparent thermal activation energies, indicating a dominant microporous membrane transport. At 200 degrees C, a single H2 permeance of 3.1x10(-6) mol m(-2) s(-1) Pa(-1) and a H2/CO2 permselectivity of 15.2 were obtained after proper correction for the support resistance and the contribution from the defects. In the gas mixture measurement, the H2 permeance and the H2/CO2 separation factor almost remain constant at 200 degrees C with a water vapor pressure of 1.2x10(4) Pa for at least 220 h, indicating that the modified membranes are hydrothermally stable, benefiting from the integrity of the microporous structure due to the fluorocarbon modification.

ITER hydrogen isotope separation system conceptual design description

International Nuclear Information System (INIS)

Busigin, A.; Sood, S.K.; Kveton, O.K.; Dinner, P.J.; Murdoch, D.K.; Leger, D.

1990-01-01

This paper presents integrated hydrogen Isotope Separation System (ISS) designs for ITER based on requirements for plasma exhaust processing, neutral beam injection deuterium cleanup, pellet injector propellant detritiation, waste water detritiation, and breeding blanket detritiation. Specific ISS designs are developed for a machine with an aqueous lithium salt blanket (ALSB) and a machine with a solid ceramic breeding blanket (SBB). The differences in the ISS designs arising from the different blanket concepts are highlighted. It is found that the ISS designs for the two blanket concepts considered are very similar with the only major difference being the requirement for an additional large water distillation column for ALSB water detritiation. The extraction of tritium from the ALSB is based on flash evaporation to separate the blanket water from the dissolved Li salt, with the tritiated water then being fed to the ISS for detritiation. This technology is considered to be relatively well understood in comparison to front-end processes for SBB detritiation. In the design of the cryogenic distillation portion of the ISS, it was found that the tritium inventory could be very large (> 600 g) unless specific design measures were taken to reduce it. In the designs which are presented, the tritium inventory has been reduced to about 180 g, which is less than the ITER single-failure release limit of 200 g. Further design optimization and isolation of components is expected to reduce the inventory further. (orig.)

Inverted Fuel Cell: Room-Temperature Hydrogen Separation from an Exhaust Gas by Using a Commercial Short-Circuited PEM Fuel Cell without Applying any Electrical Voltage.

Science.gov (United States)

Friebe, Sebastian; Geppert, Benjamin; Caro, Jürgen

2015-06-26

A short-circuited PEM fuel cell with a Nafion membrane has been evaluated in the room-temperature separation of hydrogen from exhaust gas streams. The separated hydrogen can be recovered or consumed in an in situ olefin hydrogenation when the fuel cell is operated as catalytic membrane reactor. Without applying an outer electrical voltage, there is a continuous hydrogen flux from the higher to the lower hydrogen partial pressure side through the Nafion membrane. On the feed side of the Nafion membrane, hydrogen is catalytically split into protons and electrons by the Pt/C electrocatalyst. The protons diffuse through the Nafion membrane, the electrons follow the short-circuit between the two brass current collectors. On the cathode side, protons and electrons recombine, and hydrogen is released. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Enhanced stability of Zr-doped Ba(CeTb)O(3-δ)-Ni cermet membrane for hydrogen separation.

Science.gov (United States)

Wei, Yanying; Xue, Jian; Fang, Wei; Chen, Yan; Wang, Haihui; Caro, Jürgen

2015-07-25

A mixed protonic and electronic conductor material BaCe(0.85)Tb(0.05)Zr(0.1)O(3-δ) (BCTZ) is prepared and a Ni-BCTZ cermet membrane is synthesized for hydrogen separation. Stable hydrogen permeation fluxes can be obtained for over 100 h through the Ni-BCTZ membrane in both dry and humid conditions, which exhibits an excellent stability compared with Ni-BaCe(0.95)Tb(0.05)O(3-δ) membrane due to the Zr doping.

Development of borosilicate glass compositions for the immobilisation of the UK's separated plutonium stocks

International Nuclear Information System (INIS)

Harrison, M. T.; Scales, C. R.

2008-01-01

The UK inventory of separated civil plutonium is expected to exceed 100 tonnes by 2010. Whilst the majority of this could be used in the manufacture of MOx (Mixed Oxide) fuel in future power generation scenarios, options for the disposal of surplus plutonium are currently being investigated by Nexia Solutions Ltd on behalf of the UK's Nuclear Decommissioning Authority (NDA). One of the options being considered is immobilisation in a durable glass matrix followed by long term storage and subsequent final repository disposal. A preliminary experimental survey assessed a selection of potential glass systems on the basis of Pu-surrogate (cerium) loading, durability, and ease of processing. Following this, a number of borosilicate compositions have been taken forward into a more detailed investigation in order to fully qualify their potential for Pu-immobilisation. The selected compositions are lanthanide borosilicate (LaBS), alkali tin silicate (ATS) and high-lanthanide alkali borosilicate (modified-MW). For this second series of experiments, hafnium was selected as the Pu surrogate, and a study of the potential waste loading as a function of temperature for the three selected compositions is described in this paper. Furthermore, several variations of the LaBS composition were fabricated in order to investigate the effect of total lanthanide content on melting temperature. The benchmark of 10 wt% HfO 2 incorporation is achievable for all three glasses with temperatures of 1200, 1300 and 1400 deg. C required for ATS, modified-MW and LaBS respectively. (authors)

Matt waste from glass separated collection: an eco-sustainable addition for new building materials.

Science.gov (United States)

Bignozzi, M C; Saccani, A; Sandrolini, F

2009-01-01

Matt waste (MW), a by-product of purification processes of cullet derived from separated glass waste collection, has been studied as filler for self-compacting concrete and as an addition for newly blended cement. Properties of self-compacting concrete compared to reference samples are reported. They include characteristics at the fresh and hardened states, and the compressive strength and porosity of mortar samples that were formulated with increasing amounts of MW to be used as cement replacement (up to 50wt.%). The effects of matt waste are discussed with respect to the mechanical and microstructural characteristics of the resulting new materials.

Thick film hydrogen sensor

Science.gov (United States)

Hoffheins, Barbara S.; Lauf, Robert J.

1995-01-01

A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors.

Comparison of methods for separating small quantities of hydrogen isotopes from an inert gas

International Nuclear Information System (INIS)

Willms, R.S.; Tuggle, D.; Birdsell, S.; Parkinson, J.; Price, B.; Lohmeir, D.

1998-03-01

It is frequent within tritium processing systems that a small amount of hydrogen isotopes (Q 2 ) must be separated from an inert gas such as He, Ar and N 2 . Thus, a study of presently available technologies for effecting such a separation was performed. A base case and seven technology alternatives were identified and a simple design of each was prepared. These technologies included oxidation-adsorption-metal bed reduction, oxidation-adsorption-palladium membrane reactor, cryogenic adsorption, cryogenic trapping, cryogenic distillation, hollow fiber membranes, gettering and permeators. It was found that all but the last two methods were unattractive for recovering Q 2 from N 2 . Reasons for technology rejection included (1) the method unnecessarily turns the hydrogen isotopes into water, resulting in a cumbersome and more hazardous operation, (2) the method would not work without further processing, and (3) while the method would work, it would only do so in an impractical way. On the other hand, getters and permeators were found to be attractive methods for this application. Both of these methods would perform the separation in a straightforward, essentially zero-waste, single step operation. The only drawback for permeators was that limited low-partial Q 2 pressure data is available. The drawbacks for getters are their susceptibility to irreversible and exothermic reaction with common species such as oxygen and water, and the lack of long-term operation of such beds. More research is envisioned for both of these methods to mature these attractive technologies

How mobile are protons in the structure of dental glass ionomer cements?

DEFF Research Database (Denmark)

Benetti, Ana Raquel; Jacobsen, Johan; Lehnhoff, Benedict

2015-01-01

The development of dental materials with improved properties and increased longevity can save costs and minimize discomfort for patients. Due to their good biocompatibility, glass ionomer cements are an interesting restorative option. However, these cements have limited mechanical strength...... the hydrogen mobility within these cements. Our findings suggest that the lower mechanical strength in glass ionomer cements results not only from the presence of pores, but also from the increased hydrogen mobility within the material. The relationship between microstructure, hydrogen mobility and strength...

Recent advances in SRS on hydrogen isotope separation using thermal cycling absorption process

Energy Technology Data Exchange (ETDEWEB)

Xiao, X.; Kit Heung, L.; Sessions, H.T. [Savannah River National Laboratory - SRNL, Aiken, SC (United States)

2015-03-15

TCAP (Thermal Cycling Absorption Process) is a gas chromatograph in principle using palladium in the column packing, but it is unique in the fact that the carrier gas, hydrogen, is being isotopically separated and the system is operated in a semi-continuous manner. TCAP units are used to purify tritium. The recent TCAP advances at Savannah River Site (SRS) include compressor-free concept for heating/cooling, push and pull separation using an active inverse column, and compact column design. The new developments allow significantly higher throughput and better reliability from 1/10 of the current production system's footprint while consuming 60% less energy. Various versions are derived in the meantime for external customers to be used in fusion energy projects.

Hydrogen recovery process

Science.gov (United States)

Baker, Richard W.; Lokhandwala, Kaaeid A.; He, Zhenjie; Pinnau, Ingo

2000-01-01

A treatment process for a hydrogen-containing off-gas stream from a refinery, petrochemical plant or the like. The process includes three separation steps: condensation, membrane separation and hydrocarbon fraction separation. The membrane separation step is characterized in that it is carried out under conditions at which the membrane exhibits a selectivity in favor of methane over hydrogen of at least about 2.5.

Separation membrane development

Energy Technology Data Exchange (ETDEWEB)

Lee, M.W. [Savannah River Technology Center, Aiken, SC (United States)

1998-08-01

A ceramic membrane has been developed to separate hydrogen from other gases. The method used is a sol-gel process. A thin layer of dense ceramic material is coated on a coarse ceramic filter substrate. The pore size distribution in the thin layer is controlled by a densification of the coating materials by heat treatment. The membrane has been tested by permeation measurement of the hydrogen and other gases. Selectivity of the membrane has been achieved to separate hydrogen from carbon monoxide. The permeation rate of hydrogen through the ceramic membrane was about 20 times larger than Pd-Ag membrane.

Vibration Considerations for Cryogenic Tanks Using Glass Bubbles Insulation

Science.gov (United States)

Werlink, Rudolph J.; Fesmire, James E.; Sass, Jared P.

2011-01-01

The use of glass bubbles as an efficient and practical thermal insulation system has been previously demonstrated in cryogenic storage tanks. One such example is a spherical, vacuum-jacketed liquid hydrogen vessel of 218,000 liter capacity where the boiloff rate has been reduced by approximately 50 percent. Further applications may include non-stationary tanks such as mobile tankers and tanks with extreme duty cycles or exposed to significant vibration environments. Space rocket launch events and mobile tanker life cycles represent two harsh cases of mechanical vibration exposure. A number of bulk fill insulation materials including glass bubbles, perlite powders, and aerogel granules were tested for vibration effects and mechanical behavior using a custom design holding fixture subjected to random vibration on an Electrodynamic Shaker. The settling effects for mixtures of insulation materials were also investigated. The vibration test results and granular particle analysis are presented with considerations and implications for future cryogenic tank applications. A thermal performance update on field demonstration testing of a 218,000 L liquid hydrogen storage tank, retrofitted with glass bubbles, is presented. KEYWORDS: Glass bubble, perlite, aerogel, insulation, liquid hydrogen, storage tank, mobile tanker, vibration.

Charge separation technique for metal-oxide-silicon capacitors in the presence of hydrogen deactivated dopants

International Nuclear Information System (INIS)

Witczak, Steven C.; Winokur, Peter S.; Lacoe, Ronald C.; Mayer, Donald C.

2000-01-01

An improved charge separation technique for metal-oxide-silicon (MOS) capacitors is presented which accounts for the deactivation of substrate dopants by hydrogen at elevated irradiation temperatures or small irradiation biases. Using high-frequency capacitance-voltage (C-V) measurements, radiation-induced inversion voltage shifts are separated into components due to oxide trapped charge, interface traps and deactivated dopants, where the latter is computed from a reduction in Si capacitance. In the limit of no radiation-induced dopant deactivation, this approach reduces to the standard midgap charge separation technique used widely for the analysis of room-temperature irradiations. The technique is demonstrated on a p-type MOS capacitor irradiated with 60 Co γ-rays at 100 C and zero bias, where the dopant deactivation is significant

MoO{sub 3} incorporation in magnesium aluminosilicate glasses

Energy Technology Data Exchange (ETDEWEB)

Tan, Shengheng; Ojovan, Michael I.; Hyatt, Neil C.; Hand, Russell J.

2015-03-15

Molybdate has a very low solubility in silicate and borosilicate glass systems and its excess presence in nuclear waste glass can cause the formation of a readily soluble “yellow phase”. In this study, the incorporation of molybdenum oxide (MoO{sub 3}) in a magnesium aluminosilicate glass system has been investigated. The prepared glasses show a higher than 90% molybdenum retention rate and up to 5.34 mol% (12.28 wt%) MoO{sub 3} can be incorporated into these glasses without causing visible phase separation. The incorporation of MoO{sub 3} increases glass density, decreases glass transition and crystallisation temperatures and intensifies Raman bands assigned to vibrations of MoO{sub 4}{sup 2−} units. When excess molybdate is added liquid–liquid phase separation and crystallisation occurs. The separated phase is spherical, 200–400 nm in diameter and randomly dispersed. Based on powder X-ray diffraction, Raman spectroscopy and transmission electron microscopy, the separated phase is identified as MgMoO{sub 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)

Optochemical sensing of hydrogen chloride gas using meso-tetramesitylporphyrin deposited glass plate

International Nuclear Information System (INIS)

Kalimuthu, Palanisamy; Abraham John, S.

2008-01-01

Meso-tetramesitylporphyrin (MTMP) deposited glass plate (solid state sensor) was used to sense hydrogen chloride (HCl) gas based on optochemical method. Exposure of the solid state sensor to HCl vapor results in the formation of protonated meso-tetramesitylporphyrin (PMTMP). UV-vis and fluorescence spectral techniques were used to study the protonation of MTMP in dichloromethane-methanol mixture. The optical spectra of MTMP show an intense Soret band at 418 nm with a 14 nm red shift upon protonation by HCl. Ab-initio calculations were carried out to visualize the effect of protonation on planarity and stability of the porphyrin ring. The solid state sensor was characterized by UV-vis spectral technique. The sensor exhibits characteristic Soret and Q bands for the deposited MTMP with slight red shift when compared to MTMP in dichloromethane. The concentration of gaseous HCl was monitored from the changes in the absorbance of Soret band of PMTMP at 452 nm. The detection limit of the solid state sensor towards gaseous HCl was found to be 0.03 ppm. The present solid state sensor was highly stable for several months

ASU nitrogen sweep gas in hydrogen separation membrane for production of HRSG duct burner fuel

Science.gov (United States)

Panuccio, Gregory J.; Raybold, Troy M.; Jamal, Agil; Drnevich, Raymond Francis

2013-04-02

The present invention relates to the use of low pressure N2 from an air separation unit (ASU) for use as a sweep gas in a hydrogen transport membrane (HTM) to increase syngas H2 recovery and make a near-atmospheric pressure (less than or equal to about 25 psia) fuel for supplemental firing in the heat recovery steam generator (HRSG) duct burner.

Economic assessment of a waste hydrogen utilization project

International Nuclear Information System (INIS)

Wang, L.; Zhou, H.; Zhou, W.; Wu, J.; Wang, Q.

1993-01-01

This paper reports the economic assessment on an hybrid hydrogen recovery, purification, storage, transportation and application project (HRPSTA) set for a system including a nitrogenous fertilizer plant and a float glass factory. A pretreatment unit and metal hydride containers are used to recover and purify the hydrogen from the purge gas of the ammonia fertilizer plant and to transport and use the hydrogen on the tin bath in the float glass factory. Cost analysis and cash flow statements are presented, and financial value and rate of return are calculated. The project is shown to be technologically and financially feasible. 1 fig., 4 tabs., 4 refs

Dynamics of glass-forming liquids

DEFF Research Database (Denmark)

Hansen, Henriette Wase

on alpha relaxation dynamics, and for the two van der Waals liquids, also when we have separation of timescales, i.e. the alpha relaxation is not contributing to the picosecond dynamics. The concept of isomorphs is observed to break down in two cases for the hydrogen bonding system: in density scaling......The overall theme of this work has been to experimentally test the shoving model and isomorph theory related to the dynamics of glass-forming liquids, both of which, rather than being universal explanations, are expected to work in the simplest case. We test the connection between fast and slow...... dynamics in light of the shoving model from the temperature dependence of the mean-squared displacement from neutron scattering at nanosecond timescale and the elastic modulus from shear mechanics. We find the fast dynamics to correlate with the alpha relaxation time and fragility in agreement...

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

Fabrication and characterization of chromium-doped nanophase separated yttria-alumina-silica glass-based optical fibers

Energy Technology Data Exchange (ETDEWEB)

Dutta, Debjit; Dhar, Anirban; Das, Shyamal; Paul, Mukul C. [Fiber Optics and Photonics Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata (India); Kir' yanov, Alexander V. [Centro de Investigaciones en Optica, Guanajuato (Mexico); Bysakh, Sandip [Electron Microscopic Section, Material Characterization Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata (India)

2015-08-15

The basic material and optical properties of chromium-doped nanophase-separated yttria-alumina-silica (YAS) glass based optical preforms and fibers, fabricated through the modified chemical vapor deposition process in conjunction with solution doping technique under suitable thermal annealing conditions are reported. The size of the phase-separated particles within the core of the annealed preform is around 20-30 nm which is significantly reduced to around 5.0 nm in the drawn fiber. The absorption spectra of fibers drawn from the annealed and non-annealed preform samples revealed the presence of Cr{sup 4+}, Cr{sup 3+}, and Cr{sup 6+} specie. Numerically, extinction of absorption drops ∝3-3.5 times for the annealed sample as a result of nano-phase restructuration during annealing process. Intense broadband emission (within 500-800 nm) in case of the annealed preform sample is observed as compared to the non-annealed one and is associated with the presence of Cr{sup 3+} ions in nanostructured environment inside the YAS core glass. The final fibers show broadband emission ranging from 900 to 1400 nm under pumping at 1064 nm which is attributed mainly to the presence of Cr{sup 3+}/Cr{sup 4+} ions. The fabricated fibers seem to be a potential candidate for the development of fiber laser sources for the visible and near-infra ranges and for effective Q-switching units for ∝1-1.1 μm all-fiber ytterbium lasers. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The ions displacement through glasses

International Nuclear Information System (INIS)

Sevegnani, F.X.

1980-01-01

A method to introduce sodium, potassium, lithium, calcium, iron and other ions in vacuum or gas light bulb by mean of a strong stationay electric field. The experiments showed that the mass deposited inside the bulbs obey Faraday's law of electrolysis, although the process of mass transfer is not that of a conventional electrolysis. A method which allows to show that hydrogen ions do not penetrate the glass structure is also described. Using radioactive tracers, it is shown that heavy ions, such PO 4 --- do not penetrate the glass structure. The vitreous state and the glass properties were studied for interpreting experimental results. (Author) [pt

On the nature of low temperature internal friction peaks in metallic glasses

Energy Technology Data Exchange (ETDEWEB)

Khonik, V.A. [State Pedagogical Univ., Voronezh (Russian Federation); Spivak, L.V. [State Univ., Perm (Russian Federation)

1996-01-01

Low temperature (30 < T < 300 K) internal friction in a metallic glass Ni{sub 60}Nb{sub 40} subjected to preliminary inhomogeneous deformation by cold rolling, homogeneous tensile deformation or electrolytic charging with hydrogen is investigated. Cold rolling or hydrogenation result in appearance of similar internal friction peaks and hysteresis damping. Homogeneous deformation has no influence on low temperature internal friction. The phenomenon of microplastic deformation during hydrogenation of weakly stressed samples is revealed. It is argued that microplastic deformation of metallic glasses during hydrogenation without external stress takes place too. Plastic flow both on cold rolling and hydrogenation occurs via formation and motion of dislocation-like defects which are the reason of the observed anelastic anomalies. It is concluded that low temperature internal friction peaks described in the literature for as-cast, cold deformed and hydrogenated samples have common dislocation-like origin.

Compositional threshold for Nuclear Waste Glass Durability

International Nuclear Information System (INIS)

Kruger, Albert A.; Farooqi, Rahmatullah; Hrma, Pavel R.

2013-01-01

Within the composition space of glasses, a distinct threshold appears to exist that separates 'good' glasses, i.e., those which are sufficiently durable, from 'bad' glasses of a low durability. The objective of our research is to clarify the origin of this threshold by exploring the relationship between glass composition, glass structure and chemical durability around the threshold region

Nitrate glass

International Nuclear Information System (INIS)

Kirilenko, I.A.; Vinogradov, E.E.

1977-01-01

Experimental evidence on behaviour of nitrate glasses is reviewed in terms of relationships between the presence of water in vitrescent nitrate systems and the properties of the systems. The glasses considered belong to systems of Mg(NO 3 ) 2 - Nd(NO 3 ) 3 ; Hg(NO 3 ) 2 -Nd(NO 3 ) 3 ; NaNO 3 -Mg(NO 3 ) 2 -Nd(NO 3 ) 3 ; M-Zn(NO 3 ) 3 , where M is a mixture of 20% mass NaNO 3 and 80% mass Mg(NO 3 ) 2 , and Zn is a rare earth ion. Nitrate glass is shown to be a product of dehydration. Vitrification may be regarded as a resusl of formation of molecular complexes in the chain due to hydrogen bonds of two types, i.e. water-water, or water-nicrate group. Chain formation, along with low melting points of the nitrates, hinder crystallization of nitrate melts. Provided there is enough water, this results in vitrification

Scalable and efficient separation of hydrogen isotopes using graphene-based electrochemical pumping

Science.gov (United States)

Lozada-Hidalgo, M.; Zhang, S.; Hu, S.; Esfandiar, A.; Grigorieva, I. V.; Geim, A. K.

2017-05-01

Thousands of tons of isotopic mixtures are processed annually for heavy-water production and tritium decontamination. The existing technologies remain extremely energy intensive and require large capital investments. New approaches are needed to reduce the industry's footprint. Recently, micrometre-size crystals of graphene are shown to act as efficient sieves for hydrogen isotopes pumped through graphene electrochemically. Here we report a fully-scalable approach, using graphene obtained by chemical vapour deposition, which allows a proton-deuteron separation factor of around 8, despite cracks and imperfections. The energy consumption is projected to be orders of magnitude smaller with respect to existing technologies. A membrane based on 30 m2 of graphene, a readily accessible amount, could provide a heavy-water output comparable to that of modern plants. Even higher efficiency is expected for tritium separation. With no fundamental obstacles for scaling up, the technology's simplicity, efficiency and green credentials call for consideration by the nuclear and related industries.

Connectivity of glass structure. Oxygen number

Science.gov (United States)

Medvedev, E. F.; Min'ko, N. I.

2018-03-01

With reference to mathematics, crystal chemistry and chemical technology of synthesis of glass structures in the solution (sol-gel technology), the paper is devoted to the study of the degree of connectivity of a silicon-oxygen backbone (fSi) and the oxygen number (R) [1]. It reveals logical contradictions and uncertainty of mathematical expressions of parameters, since fSi is not similar to the oxygen number. The connectivity of any structure is a result of various types of bonds: ion-covalent, donor-acceptor, hydrogen bonds, etc. Besides, alongside with SiO2, many glass compositions contain other glass-forming elements due to tetrahedral sites thus formed. The connectivity function of a glassy network with any set of glass-forming elements is roughly ensured by connectivity factor Y [2], which has monovalent elements loosening a glassy network. The paper considers the existence of various structural motives in hydrogen-impermeable glasses containing B2O3, Al2O3, PbO, Na2O, K2O and rare-earth elements. Hence, it also describes gradual nucleation, change of crystal forms, and structure consolidation in the process of substance intake from a matrix solution according to sol-gel technology. The crystal form varied from two-dimensional plates to three-dimensional and dendritical ones [3]. Alternative parameters, such as the oxygen number (O) and the structure connectivity factor (Y), were suggested. Functional dependence of Y=f(O) to forecast the generated structures was obtained for two- and multicomponent glass compositions.

Investigation of metastable immiscibility in nuclear-waste-glasses. I-III

International Nuclear Information System (INIS)

Egnell, J.; Larsen, J.G.; Moeller, L.; Roed, G.

1981-12-01

Metastable liquid-liquid separation in glasses can often cause significant changes in physical and chemical properties of the original homogeneous glass. In some technical borosilicate glasses this phenomenon is used to change the chemical durability of the glass. For potential nuclear-waste-glasses the slow cooling through the temperature range 550 0 C - 700 0 C may lead to such a liquid-liquid phase separation. In order to investigate the susceptibility of phase separation of nuclear-waste-glasses, two KBS model glasses, ABS-39 and ABS-41, were investigated. Two of the subsequent reports are concerned with this problem. The third report also takes into consideration the effects of MoO 3 on the immiscibility gap. The maximum amount of MoO 3 that can be dissolved in ABS-39 and ABS 41 is also determined. (Auth.)

Testing a technical-scale counterflow compact heat exchanger for the separation of uranium hexafluoride from hydrogen

International Nuclear Information System (INIS)

Hornberger, P.; Seidel, D.; Steinhaus, H.

1981-07-01

When enriching the light uranium isotope U-235 according to the separation nozzle method, UF 6 and light auxiliary gas (H 2 ) must be separated from each other at the head as well as at the shoulder of the cascade. After pre-separation at a special separation nozzle stage, fine separation is planned by means of a low-temperature separator made as a compact heat exchanger. This report describes first testing under process conditions of a representative section of the separator blocks intended for technical-scale operation. It is proved that the rated loading capacity is attained while the residual UF 6 concentration contained in the escaping hydrogen can be lowered down to values less than 1 ppm. It is further shown that the requirement of constant pressure drop at the separator, which is decisive for the smooth interplay of preseparator stage and low-temperature separator, can be imposed by direct control of the supply of the refrigerating medium through the variable to be kept constant. A concept of control is proposed for industrial application necessitating the operation of several low-temperature separators staggered in terms of time. This concept allows the relatively simple optimum utilization of the separator capacity even under variable operating conditions. (orig.) [de

Compression-recovery model of absorptive glass mat (AGM) separator guided by X-ray micro-computed tomography analysis

Science.gov (United States)

Kameswara Rao, P. V.; Rawal, Amit; Kumar, Vijay; Rajput, Krishn Gopal

2017-10-01

Absorptive glass mat (AGM) separators play a key role in enhancing the cycle life of the valve regulated lead acid (VRLA) batteries by maintaining the elastic characteristics under a defined level of compression force with the plates of the electrodes. Inevitably, there are inherent challenges to maintain the required level of compression characteristics of AGM separators during the charge and discharge of the battery. Herein, we report a three-dimensional (3D) analytical model for predicting the compression-recovery behavior of AGM separators by formulating a direct relationship with the constituent fiber and structural parameters. The analytical model of compression-recovery behavior of AGM separators has successfully included the fiber slippage criterion and internal friction losses. The presented work uses, for the first time, 3D data of fiber orientation from X-ray micro-computed tomography, for predicting the compression-recovery behavior of AGM separators. A comparison has been made between the theoretical and experimental results of compression-recovery behavior of AGM samples with defined fiber orientation characteristics. In general, the theory agreed reasonably well with the experimental results of AGM samples in both dry and wet states. Through theoretical modeling, fiber volume fraction was established as one of the key structural parameters that modulates the compression hysteresis of an AGM separator.

Economic assessment of a waste hydrogen utilization project

International Nuclear Information System (INIS)

Zhou, H.; Wang, L.; Zhou, W.; Wu, J.; Wang, Q.

1993-01-01

This article reports an economic assessment on a hydride hydrogen recovery, purification, storage, transportation and application project (HRPSTA) set for a system including a nitrogenous fertilizer plant and a float glass factory. In this project, a pretreatment unit and metal hydride containers are used to recover and purify the hydrogen from the purge gas of the ammonia fertilizer plant and to transport and use the hydrogen in the tin bath in the float glass factory. Detailed economic assessment, cost analysis and a cash flow statement are presented, and financial net present value (NPV), as well as intrinsic rate of return (IRR), is calculated. The results shows that this project, which is feasible technologically, is profitable economically. (Author)

Predicting the glass transition temperature of bioactive glasses from their molecular chemical composition.

Science.gov (United States)

Hill, Robert G; Brauer, Delia S

2011-10-01

A recently published paper (M.D. O'Donnell, Acta Biomaterialia 7 (2011) 2264-2269) suggests that it is possible to correlate the glass transition temperature (T(g)) of bioactive glasses with their molar composition, based on iterative least-squares fitting of published T(g) data. However, we show that the glass structure is an important parameter in determining T(g). Phase separation, local structural effects and components (intermediate oxides) which can switch their structural role in the glass network need to be taken into consideration, as they are likely to influence the glass transition temperature of bioactive glasses. Although the model suggested by O'Donnell works reasonably well for glasses within the composition range presented, it is oversimplified and fails for glasses outside certain compositional boundaries. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Hydrogen selective NH{sub 2}-MIL-53(Al) MOF membranes with high permeability

Energy Technology Data Exchange (ETDEWEB)

Zhang, Feng; Zou, Xiaoqin; Gao, Xue; Fan, Songjie; Sun, Fuxing; Ren, Hao; Zhu, Guangshan [State Key Laboratory of Inorganic, Synthesis and Preparative Chemistry, Jilin University, Changchun (China)

2012-09-11

Hydrogen-based energy is a promising renewable and clean resource. Thus, hydrogen selective microporous membranes with high performance and high stability are demanded. Novel NH{sub 2}-MIL-53(Al) membranes are evaluated for hydrogen separation for this goal. Continuous NH{sub 2}-MIL-53(Al) membranes have been prepared successfully on macroporous glass frit discs assisted with colloidal seeds. The gas sorption ability of NH{sub 2}-MIL-53(Al) materials is studied by gas adsorption measurement. The isosteric heats of adsorption in a sequence of CO{sub 2}> N{sub 2}> CH{sub 4}{approx} H{sub 2} indicates different interactions between NH{sub 2}-MIL-53(Al) framework and these gases. As-prepared membranes are measured by single and binary gas permeation at different temperatures. The results of singe gas permeation show a decreasing permeance in an order of H{sub 2}> CH{sub 4}> N{sub 2}> CO{sub 2}, suggesting that the diffusion and adsorption properties make significant contributions in the gas permeation through the membrane. In binary gas permeation, the NH{sub 2}-MIL-53(Al) membrane shows high selectivity for H{sub 2} with separation factors of 20.7, 23.9 and 30.9 at room temperature (288 K) for H{sub 2} over CH{sub 4}, N{sub 2} and CO{sub 2}, respectively. In comparison to single gas permeation, a slightly higher separation factor is obtained due to the competitive adsorption effect between the gases in the porous MOF membrane. Additionally, the NH{sub 2}-MIL-53(Al) membrane exhibits very high permeance for H{sub 2} in the mixtures separation (above 1.5 x 10{sup -6} mol m{sup -2} s{sup -1} Pa{sup -1}) due to its large cavity, resulting in a very high separation power. The details of the temperature effect on the permeances of H{sub 2} over other gases are investigated from 288 to 353 K. The supported NH{sub 2}-MIL-53(Al) membranes with high hydrogen separation power possess high stability, resistance to cracking, temperature cycling and show high reproducibility

Resistance of HEPA filter separator materials to humid air--hydrogen fluoride--fluorine environments

International Nuclear Information System (INIS)

Weber, C.W.; Petit, G.S.; Woodfin, S.B.

1977-01-01

The U. S. Energy Research and Development Administration (ERDA) is interested in the development of a high-efficiency particulate air (HEPA) filter that is resistant to such corrosive reagents as hydrogen fluoride (HF) and fluorine (F 2 ) in air environments of normal relative humidity (about 50% RH). Several types of separator materials are used in the fabrication of commercial filters. The basic types of separator materials are asbestos, Kraft paper, plastic, and aluminum. At the request of the ERDA Division of Operational Safety, the different types of separator materials have been evaluated for their resistance to corrosive attack by HF and F 2 . The separator materials were dynamically tested in the 4-stage multiunit tester located in the Oak Ridge Gaseous Diffusion Plant laboratories. This is the system previously used in the evaluation of the Herty Foundation filter paper samples. Concurrent with the testing of filter media for its resistance to HF and F 2 , another component of the completed filter, the separator, was tested. All samples were exposed to a constant air flow (50% RH) of 32 liters/min, at 100 0 F, containing 900 ppM HF and 300 ppM F 2 . Exposure periods varied from 2 to 1000 h; however, the longer exposures were made only on the stronger candidates. Test results show the plastic and aluminum separator materials to be superior to the other types in resistance to HF and F 2 . The asbestos separators disintegrated after a relatively short exposure time; the Kraft paper types were the next weakest. The Clear Plastic S was the best performer of the plastics tested

Comment on 'Spherical 2+p spin-glass model: An analytically solvable model with a glass-to-glass transition'

International Nuclear Information System (INIS)

Krakoviack, V.

2007-01-01

Guided by old results on simple mode-coupling models displaying glass-glass transitions, we demonstrate, through a crude analysis of the solution with one step of replica symmetry breaking (1RSB) derived by Crisanti and Leuzzi for the spherical s+p mean-field spin glass [Phys. Rev. B 73, 014412 (2006)], that the phase behavior of these systems is not yet fully understood when s and p are well separated. First, there seems to be a possibility of glass-glass transition scenarios in these systems. Second, we find clear indications that the 1RSB solution cannot be correct in the full glassy phase. Therefore, while the proposed analysis is clearly naive and probably inexact, it definitely calls for a reassessment of the physics of these systems, with the promise of potentially interesting developments in the theory of disordered and complex systems

Containment hydrogen removal system for a nuclear power plant

International Nuclear Information System (INIS)

Callaghan, V.M.; Flynn, E.P.; Pokora, B.M.

1984-01-01

A hydrogen removal system (10) separates hydrogen from the containment atmosphere of a nuclear power plant using a hydrogen permeable membrane separator (30). Water vapor is removed by condenser (14) from a gas stream withdrawn from the containment atmosphere. The gas stream is then compressed by compressor (24) and cooled (28,34) to the operating temperature of the hydrogen permeable membrane separator (30). The separator (30) separates the gas stream into a first stream, rich in hydrogen permeate, and a second stream that is hydrogen depleted. The separated hydrogen is passed through a charcoal adsorber (48) to adsorb radioactive particles that have passed through the hydrogen permeable membrane (44). The hydrogen is then flared in gas burner (52) with atmospheric air and the combustion products vented to the plant vent. The hydrogen depleted stream is returned to containment through a regenerative heat exchanger (28) and expander (60). Energy is extracted from the expander (60) to drive the compressor (24) thereby reducing the energy input necessary to drive the compressor (24) and thus reducing the hydrogen removal system (10) power requirements

Fine-Tuned Intrinsically Ultramicroporous Polymers Redefine the Permeability/Selectivity Upper Bounds of Membrane-Based Air and Hydrogen Separations

KAUST Repository

Swaidan, Raja

2015-08-20

Intrinsically ultramicroporous (<7 Å) polymers represent a new paradigm in materials development for membrane-based gas separation. In particular, they demonstrate that uniting intrachain “rigidity”, the traditional design metric of highly permeable polymers of intrinsic microporosity (PIMs), with gas-sieving ultramicroporosity yields high-performance gas separation membranes. Highly ultramicroporous PIMs have redefined the state-of-the-art in large-scale air (e.g., O2/N2) and hydrogen recovery (e.g., H2/N2, H2/CH4) applications with unprecedented molecular sieving gas transport properties. Accordingly, presented herein are new 2015 permeability/selectivity “upper bounds” for large-scale commercial membrane-based air and hydrogen applications that accommodate the substantial performance enhancements of recent PIMs over preceding polymers. A subtle balance between intrachain rigidity and interchain spacing has been achieved in the amorphous microstructures of PIMs, fine-tuned using unique bridged-bicyclic building blocks (i.e., triptycene, ethanoanthracene and Tröger’s base) in both ladder and semiladder (e.g., polyimide) structures.

The modernization and improvement of the BNL short separators

International Nuclear Information System (INIS)

Kovarik, V.; Montemurro, P.; Sandberg, J.; Hulliger, R.

1979-01-01

Two high voltage separators (10 and 15 cm gaps) have been designed, constructed, and tested for use in the new LESB II experimental beam line. Both separators have been tested to 800 kV (limited by power supply capability). The 10 cm gap separator is of the conventional heated glass-cathode, steel-anode design. The 15 cm gap separator has a glass cathode and glass anode. This separator has been conditioned above 780 kV in hard vacuum (10 -6 torr range). In order to attain and reliably maintain the high voltages necessary for testing the separator, the power supplies, cable terminations, feedthroughs, high voltage bushings, standoffs, and surge resistors have all been modified. These modifications and the final test results are discussed in detail. (Auth.)

Predicting liquid immiscibility in multicomponent nuclear waste glasses

International Nuclear Information System (INIS)

Peeler, D.K.; Hrma, P.R.

1994-04-01

Taylor's model for predicting amorphous phase separation in complex, multicomponent systems has been applied to high-level (simulated) radioactive waste glasses at the US Department of Energy's Hanford site. Taylor's model is primarily based on additions of modifying cations to a Na 2 O-B 2 O 3 -SiO 2 (NBS) submixture of the multicomponent glass. The position of the submixture relative to the miscibility dome defines the development probability of amorphous phase separation. Although prediction of amorphous phase separation in Hanford glasses (via experimental SEM/TEM analysis) is the primary thrust of this work; reported durability data is also provides limited insight into the composition/durability relationship. Using a modified model similar to Taylor's, the results indicate that immiscibility may be predicted for multicomponent waste glasses by the addition of Li 2 O to the ''alkali'' corner of the NBS submixture

Multi-component transport in polymers: hydrocarbon / hydrogen separation by reverse selectivity membrane; Transport multi-composants dans les polymeres: separation hydrocarbures / hydrogene par membrane a selectivite inverse

Energy Technology Data Exchange (ETDEWEB)

Mauviel, G.

2003-12-15

Hydrogen separation by reverse selectivity membranes is investigated. The first goal is to develop materials showing an increased selectivity. Silicone membranes loaded with inorganic fillers have been prepared, but the expected enhancement is not observed. The second goal is to model the multi- component transport through rubbers. Indeed the permeability model is not able to predict correctly permeation when a vapour is present. Thus many phenomena have to be considered: diffusional inter-dependency, sorption synergy, membrane swelling and drag effect. The dependence of diffusivities with the local composition is modelled according to free-volume theory. The model resolution allows to predict the permeation flow-rates of mixed species from their pure sorption and diffusion data. For the systems under consideration, the diffusional inter-dependency is shown to be preponderant. Besides, sorption synergy importance is pointed out, whereas it is most often neglected. (author)

Fluctuations in an Inorganic Glass Forming System Capable of Liquid-Liquid Phase Separation

Science.gov (United States)

Bogdanov, V.; Maksimov, L.; Anan'ev, A.; Nemilov, S.; Rusan, V.

2012-08-01

Rayleigh and Mandel'shtam-Brillouin scattering (RMBS) spectroscopy and high temperature ultrasonic study (HTUS) are applied to PbO-Al2O3-B2O3 glass forming system characterized by over liquidus miscibility gap. Temperature dependences of ultrasonic velocity of glass melts were measured in 600-1200°C range. "Frozen-in" density fluctuations in two phase glasses were estimated from HTUS data by Macedo-Shroeder formulation. Landau-Placzek ratios were found from RMBS spectra of single phase glasses at room temperature. Results of RMBS and HTUS were compared with well-known SAXS data. It was found that contribution of "frozen-in" density fluctuations into light scattering by two-phase glasses is much smaller than the scattering on particles of the second glassy phase causing opalescence of the glasses. Abnormal "water-like" growth of ultrasonic velocity with melt temperature can be explained by coexistence of two types of packaging of structural elements.

Bone bonding ability of some borate bio-glasses and their corresponding glass-ceramic derivatives

Directory of Open Access Journals (Sweden)

Fatma H. Margha

2012-12-01

Full Text Available Ternary borate glasses from the system Na2O·CaO·B2O3 together with soda-lime-borate samples containing 5 wt.% of MgO, Al2O3, SiO2 or P2O5 were prepared. The obtained glasses were converted to their glass-ceramic derivatives by controlled heat treatment. X-ray diffraction was employed to investigate the separated crystalline phases in glass-ceramics after heat treatment of the glassy samples. The glasses and corresponding glass-ceramics after immersion in water or diluted phosphate solution for extended times were characterized by the grain method (adopted by several authors and recommended by ASTM and Fourier-transform infrared spectra to justify the formation of hydroxyapatite as an indication of the bone bonding ability. The influence of glass composition on bioactivity potential was discussed too.

Modeling of hydrogen isotopes separation in a metal hydride bed

International Nuclear Information System (INIS)

Charton, S.; Corriou, J.P.; Schweich, D.

1999-01-01

A predictive model for hydrogen isotopes separation in a non-isothermal bed of unsupported palladium hydride particles is derived. It accounts for the non-linear adsorption-dissociation equilibrium, hydrodynamic dispersion, pressure drop, mass transfer kinetics, heat of sorption and heat losses at the bed wall. Using parameters from the literature or estimated with classical correlations, the model gives simulated curves in agreement with previously published experiments without any parameter fit. The non-isothermal behavior is shown to be responsible for drastic changes of the mass transfer rate which is controlled by diffusion in the solid-phase lattice. For a feed at 300 K and atmospheric pressure, the endothermic hydride-to-deuteride exchange is kinetically controlled, whereas the reverse exothermic exchange is nearly at equilibrium. Finally, a simple and efficient thermodynamic model for the dissociative equilibrium between a metal and a diatomic gas is proposed. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Predicting liquid immiscibility in multicomponent nuclear waste glasses

International Nuclear Information System (INIS)

Peeler, D.K.; Hrma, P.R.

1994-01-01

Taylor's model for predicting amorphous phase separation in complex, multicomponent systems has been applied to high-level (simulated) radioactive waste glasses at the U.S. Department of Energy's Hanford site. Taylor's model is primarily based on additions of modifying cations to a Na 2 O-B 2 O 3 -SiO 2 (NBS) submixture of the multicomponent glass. The position of the submixture relative to the immiscibility dome defines the development probability of amorphous phase separation. Although prediction of amorphous phase separation in Hanford glasses (via experimental SEM/TEM analysis) is the primary thrust of this work; reported durability data is also provides limited insight into the composition/durability relationship. Using a modified model similar to Taylor's, the results indicate that immiscibility may be predicted for multicomponent waste glasses by the addition of Li 2 O to the open-quotes alkaliclose quotes corner of the NBS submixture

Crack tip fracture toughness of base glasses for dental restoration glass-ceramics using crack opening displacements.

Science.gov (United States)

Deubener, J; Höland, M; Höland, W; Janakiraman, N; Rheinberger, V M

2011-10-01

The critical stress intensity factor, also known as the crack tip toughness K(tip), was determined for three base glasses, which are used in the manufacture of glass-ceramics. The glasses included the base glass for a lithium disilicate glass-ceramic, the base glass for a fluoroapatite glass-ceramic and the base glass for a leucite glass-ceramic. These glass-ceramic are extensively used in the form of biomaterials in restorative dental medicine. The crack tip toughness was established by using crack opening displacement profiles under experimental conditions. The crack was produced by Vickers indentation. The crack tip toughness parameters determined for the three glass-ceramics differed quite significantly. The crack tip parameters of the lithium disilicate base glass and the leucite base glass were higher than that of the fluoroapatite base glass. This last material showed glass-in-glass phase separation. The discussion of the results clearly shows that the droplet glass phase is softer than the glass matrix. Therefore, the authors conclude that a direct relationship exists between the chemical nature of the glasses and the crack tip parameter. Copyright © 2011 Elsevier Ltd. All rights reserved.

Hydrogen anode for nitrate waste destruction. Revision 2

International Nuclear Information System (INIS)

Hobbs, D.T.; Kalu, E.E.; White, R.E.

1996-01-01

Large quantities of radioactive and hazardous wastes have been generated from nuclear materials production during the past fifty years. Processes are under evaluation to separate the high level radioactive species from the waste and store them permanently in the form of durable solids. The schemes proposed will separate the high level radioactive components, cesium-137 and strontium-90, into a small volume for incorporation into a glass wasteform. The remaining low-level radioactive waste contain species such as nitrites and nitrates that are capable of contaminating ground water. Electrochemical destruction of the nitrate and nitrite before permanent storage has been proposed. Not only will the electrochemical processing destroy these species, the volume of the waste could also be reduced. The use of a hydrogen gas-fed anode and an acid anolyte in an electrochemical cell used to destroy nitrate was demonstrated. A mixed Na 2 SO 4 /H 2 SO 4 anolyte was shown to favor the nitrate cell performance, and the generation of a higher hydroxide ion concentration in the catholyte. The suggested scheme is an apparent method of sodium sulfate disposal and a possible means through which ammonia (to ammonium sulfate, fertilizer) and hydrogen gas could be recycled through the anode side of the reactor. This could result in a substantial savings in the operation of a nitrate destruction cell

Biomass-derived porous carbon modified glass fiber separator as polysulfide reservoir for Li-S batteries.

Science.gov (United States)

Selvan, Ramakrishnan Kalai; Zhu, Pei; Yan, Chaoi; Zhu, Jiadeng; Dirican, Mahmut; Shanmugavani, A; Lee, Yun Sung; Zhang, Xiangwu

2018-03-01

Biomass-derived porous carbon has been considered as a promising sulfur host material for lithium-sulfur batteries because of its high conductive nature and large porosity. The present study explored biomass-derived porous carbon as polysulfide reservoir to modify the surface of glass fiber (GF) separator. Two different carbons were prepared from Oak Tree fruit shells by carbonization with and without KOH activation. The KOH activated porous carbon (AC) provides a much higher surface area (796 m 2  g -1 ) than pyrolized carbon (PC) (334 m 2  g -1 ). The R factor value, calculated from the X-ray diffraction pattern, revealed that the activated porous carbon contains more single-layer sheets with a lower degree of graphitization. Raman spectra also confirmed the presence of sp 3 -hybridized carbon in the activated carbon structure. The COH functional group was identified through X-ray photoelectron spectroscopy for the polysulfide capture. Simple and straightforward coating of biomass-derived porous carbon onto the GF separator led to an improved electrochemical performance in Li-S cells. The Li-S cell assembled with porous carbon modified GF separator (ACGF) demonstrated an initial capacity of 1324 mAh g -1 at 0.2 C, which was 875 mAh g -1 for uncoated GF separator (calculated based on the 2nd cycle). Charge transfer resistance (R ct ) values further confirmed the high ionic conductivity nature of porous carbon modified separators. Overall, the biomass-derived activated porous carbon can be considered as a promising alternative material for the polysulfide inhibition in Li-S batteries. Copyright © 2017 Elsevier Inc. All rights reserved.

Bulk glass ceramics containing Yb{sup 3+}/Er{sup 3+}: β-NaGdF{sub 4} nanocrystals: Phase-separation-controlled crystallization, optical spectroscopy and upconverted temperature sensing behavior

Energy Technology Data Exchange (ETDEWEB)

Chen, Daqin, E-mail: dqchen@fjirsm.ac.cn [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Wan, Zhongyi; Zhou, Yan [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Huang, Ping, E-mail: phuang@fjirsm.ac.cn [Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Zhong, Jiasong; Ding, Mingye [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Xiang, Weidong; Liang, Xiaojuan [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035 (China); Ji, Zhenguo, E-mail: jizg@hdu.edu.cn [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China)

2015-07-25

Highlights: • Hexagonal NaGdF{sub 4} nanocrystals embedded bulk glass ceramics were fabricated. • The incorporation of Ln{sup 3+} dopants into the β-NaGdF{sub 4} lattice was demonstrated. • Upconversion luminescence was highly intensified after glass crystallization. • Such glass ceramics had possible application in the optical temperature sensors. - Abstract: Lanthanide doped hexagonal β-NaGdF{sub 4} nanocrystals embedded transparent bulk glass ceramics were successfully fabricated via a phase-separation-controlled crystallization route. Elemental mapping in the scanning transmission electron microscope and optical spectroscopy analysis demonstrated the partition of the active centers into the β-NaGdF{sub 4} crystalline lattice. As a result, upconversion luminescence of the glass ceramic co-doped with Yb{sup 3+} and Er{sup 3+} is about 60 times as high as that of the precursor glass, attributing to the modification of Yb{sup 3+}/Er{sup 3+} surrounding from phase-separated amorphous nanoparticle to β-NaGdF{sub 4} crystalline lattice with low phonon energy and high crystallinity after crystallization. Furthermore, the temperature-dependent green upconversion emissions assigned to {sup 2}H{sub 11/2} → {sup 4}I{sub 15/2} (520 nm) and {sup 4}S{sub 3/2} → {sup 4}I{sub 15/2} (540 nm) transitions were investigated, and the corresponding fluorescence intensity ratio of these two thermally coupled emitting-states greatly enhanced with increase of temperature. Using such fabricated glass ceramic as an optical thermometric medium, the maximum sensitivity reached as high as 0.0037 K{sup −1} at 580 K. It is expected that the investigated Er{sup 3+}/Yb{sup 3+} codoped glass ceramic might be a very promising candidate for accurate optical temperature sensors.

Glass transition, crystallization kinetics and pressure effect on crystallization of ZrNbCuNiBe bulk metallic glass

DEFF Research Database (Denmark)

Xing, P.F.; Zhuang, Yanxin; Wang, W.H.

2002-01-01

The glass transition behavior and crystallization kinetics of Zr48Nb8Cu14Ni12Be18 bulk metallic glass have been investigated by differential scanning calorimetry and x-ray powder diffraction (XRD). The activation energies of both glass transition and crystallization events have been obtained using...... the Kissinger method. Results indicate that this glass crystallizes by a three-stage reaction: (1) phase separation and primary crystallization of glass, (2) formation of intermetallic compounds, and (3) decomposition of intermetallic compounds and crystallization of residual amorphous phase. The pressure...

Thermoset composite recycling: Properties of recovered glass fiber

DEFF Research Database (Denmark)

Beauson, Justine; Fraisse, Anthony; Toncelli, C.

2015-01-01

Recycling of glass fiber thermoset polymer composite is a challenging topic and a process able to recover the glass fibers original properties in a limited cost is still under investigation. This paper focuses on the recycling technique separating the glass fiber from the matrix material. Four...

Tunable hydrogen separation in porous graphene membrane: first-principle and molecular dynamic simulation.

Science.gov (United States)

Tao, Yehan; Xue, Qingzhong; Liu, Zilong; Shan, Meixia; Ling, Cuicui; Wu, Tiantian; Li, Xiaofang

2014-06-11

First-principle density functional theory (DFT) calculation and molecular dynamic (MD) simulation are employed to investigate the hydrogen purification performance of two-dimensional porous graphene material (PG-ESX). First, the pore size of PG-ES1 (3.2775 Å) is expected to show high selectivity of H2 by DFT calculation. Then MD simulations demonstrate the hydrogen purification process of the PG-ESX membrane. The results indicate that the selectivity of H2 over several other gas molecules that often accompany H2 in industrial steam methane reforming or dehydrogenation of alkanes (such as N2, CO, and CH4) is sensitive to the pore size of the membrane. PG-ES and PG-ES1 membranes both exhibit high selectivity for H2 over other gases, but the permeability of the PG-ES membrane is much lower than the PG-ES1 membrane because of the smaller pore size. The PG-ES2 membrane with bigger pores demonstrates low selectivity for H2 over other gases. Energy barrier and electron density have been used to explain the difference of selectivity and permeability of PG-ESX membranes by DFT calculations. The energy barrier for gas molecules passing through the membrane generally increase with the decreasing of pore sizes or increasing of molecule kinetic diameter, due to the different electron overlap between gas and a membrane. The PG-ES1 membrane is far superior to other carbon membranes and has great potential applications in hydrogen purification, energy clean combustion, and making new concept membrane for gas separation.

Phase separation and nanocrystal formation in Al-based metallic glasses

International Nuclear Information System (INIS)

Antonowicz, Jerzy

2007-01-01

Nanocrystallization in a group of Al-RE and Al-RE-TM (RE = rare earth, TM = transition metal) melt-spun amorphous alloys was studied using in situ small- and wide-angle X-ray scattering techniques (SAXS/WAXS) and transmission electron microscopy (TEM). The SAXS/WAXS measurements were carried out during isothermal annealing at temperatures close to crystallization point. A continuously growing interference maximum shifting progressively toward lower angles was found to develop in SAXS regime. Simultaneously taken WAXS spectra reveal formation of the primary fcc-Al nanocrystalline phase. The presence of the SAXS signal maximum indicates the spatial correlation between the compositional fluctuations. The peak position decay is an evidence of an increase of the fluctuation spacing characteristic for the coarsening stage of phase separation. The SAXS/WAXS data analysis indicates that amorphous phase decomposition triggers and controls the fcc-Al nanocrystalline phase formation. The glassy phase initially decomposes into Al-rich and RE-rich regions with typical lengths scale of about 10 nm. The nanocrystals nucleate preferentially inside the Al-rich amorphous regions and their growth is constrained by the region size because of the sluggish atomic diffusion in the RE-rich zones. A different crystallization mechanism is demonstrated in Al-Y-Ni-Co glass where WAXS spectra show formation of the fcc-Al primary phase but no interference peak in SAXS regime was found

Precursors-Derived Ceramic Membranes for High-Temperature Separation of Hydrogen

OpenAIRE

Yuji, Iwamoto

2007-01-01

This review describes recent progress in the development of hydrogen-permselective ceramic membranes derived from organometallic precursors. Microstructure and gas transport property of microporous amorphous silica-based membranes are briefly described. Then, high-temperature hydrogen permselectivity, hydrothermal stability as well as hydrogen/steam selectivity of the amorphous silica-based membranes are discussed from a viewpoint of application to membrane reactors for conversion enhancement...

On the nature of low temperature internal friction peaks in metallic glasses

NARCIS (Netherlands)

Khonik, VA; Spivak, LV

Low temperature (30 glass Ni60Nb40 subjected to preliminary inhomogeneous deformation by cold rolling, homogeneous tensile deformation or electrolytic charging with hydrogen is investigated. Cold rolling or hydrogenation result in appearance of similar

Laser separation of isotopes of hydrogen

International Nuclear Information System (INIS)

Dave, S.M.; Ghosh, S.K.; Sadhukhan, H.K.

1980-01-01

Laser isotope separation technique is explained and various methods based on the technique are discussed in detail. Requirements of any laser isotope separation method to be acceptable for the production of heavy water are mentioned and economic viability of this process for heavy water production is examined. Investigations carried out to use this technique for deuterium separation using methanol, formaldehyde, propynal, 2,2,-dichloro-1-1-1,-trifluoroethane (Freon 123), polyvinyl chloride and fluoroform-d are reviewed. (M.G.B.)

Molybdenum sealing glass-ceramic composition

International Nuclear Information System (INIS)

Eagan, R.J.

1976-01-01

A glass-ceramic composition is described having low hydrogen and helium permeability properties, along with high fracture strength, and a thermal coefficient of expansion similar to that of molybdenum. The composition is adaptable for hermetically sealing to molybdenum at temperatures between 900 and about 950 0 C to form a hermetically sealed insulator body

Hanford Waste Vitrification Plant hydrogen generation

International Nuclear Information System (INIS)

King, R.B.; King, A.D. Jr.; Bhattacharyya, N.K.

1996-02-01

The most promising method for the disposal of highly radioactive nuclear wastes is a vitrification process in which the wastes are incorporated into borosilicate glass logs, the logs are sealed into welded stainless steel canisters, and the canisters are buried in suitably protected burial sites for disposal. The purpose of the research supported by the Hanford Waste Vitrification Plant (HWVP) project of the Department of Energy through Battelle Pacific Northwest Laboratory (PNL) and summarized in this report was to gain a basic understanding of the hydrogen generation process and to predict the rate and amount of hydrogen generation during the treatment of HWVP feed simulants with formic acid. The objectives of the study were to determine the key feed components and process variables which enhance or inhibit the.production of hydrogen. Information on the kinetics and stoichiometry of relevant formic acid reactions were sought to provide a basis for viable mechanistic proposals. The chemical reactions were characterized through the production and consumption of the key gaseous products such as H 2 . CO 2 , N 2 0, NO, and NH 3 . For this mason this research program relied heavily on analyses of the gases produced and consumed during reactions of the HWVP feed simulants with formic acid under various conditions. Such analyses, used gas chromatographic equipment and expertise at the University of Georgia for the separation and determination of H 2 , CO, CO 2 , N 2 , N 2 O and NO

Optical properties of palladium nanoparticles under exposure of hydrogen and inert gas prepared by dewetting synthesis of thin-sputtered layers

Energy Technology Data Exchange (ETDEWEB)

Kracker, Michael, E-mail: Michael.Kracker@uni-jena.de; Worsch, Christian; Ruessel, Christian [Otto-Schott-Institut, Jena University (Germany)

2013-04-15

Thin layers of palladium with a thickness of 5 nm were sputtered on fused silica substrates. Subsequently, the coated glasses were annealed at a temperature of 900 Degree-Sign C for 1 h. This resulted in the formation of small and well-separated palladium nanoparticles with diameters in the range from 20 to 200 nm on the glass surface. The existence of a palladium oxide layer can be detected using optical absorption spectroscopy. Purging with hydrogen leads to an irreversible change in the optical spectra due to the reduction of PdO to metallic palladium. Changing the gas atmosphere from hydrogen to argon leads to significant reversible changes in the optical properties of the particle layer. Based on Mie theory and the respective dielectric functions, the spectra were calculated using the real particle size distribution, weighted dispersions relation to adapt the geometrical conditions and complex dielectric functions of palladium and palladium hydride. A good agreement with measured spectra was found and the dependency of the surrounding media can be explained.Graphical Abstract.

Immobilisation of radwastes in glass containers and products formed thereby

International Nuclear Information System (INIS)

Macedo, P.B.; Simmons, C.J.; Lagakos, N.; Simmons, J.H.; Tran, D.C.

1980-01-01

A method of preventing the dissemination of toxic material to the environment comprises forming an admixture of toxic material and glass packing in a hollow doped glass container of high silica content, or forming the admixture in a first container and then depositing at least a portion of the admixture in a hollow doped glass container of high silica content. The glass container is then heated to collapse its walls and to seal the container so that the toxic material is entrapped and sealed within the collapsed doped glass container. The thermal expansion coefficient of the container may be decreased prior to use by exchanging hydrogen ion in pores thereof with other cations followed by collapsing the pores. (author)

Inward Cationic Diffusion and Formation of Silica-Rich Surface Nanolayer of Glass

DEFF Research Database (Denmark)

Smedskjær, Morten Mattrup; Deubener, Joachim; Yue, Yuanzheng

2009-01-01

form and are incorporated into the glass structure. Both the V4+ and the hydroxyl contents increase with increasing ta and hydrogen partial pressure. The inward diffusion enhances the hardness of the glass surface. The mechanism of the inward diffusion is suggested on the basis of a model describing...

Ultraviolet-induced birefringence in hydrogen-loaded optical fiber

DEFF Research Database (Denmark)

Canning, John; Deyerl, Hans-Jürgen; Sørensen, Henrik Rokkjær

2005-01-01

for the role of hydrogen and deuterium in the UV-induced process. Previous arguments for the origins are systematically ruled out by reviewing existing literature. We note that the birefringence is made up of at least two components with different thermal stabilities, one consistent simply with molecular...... hydrogen being present in the system. Overall the birefringence, by deduction, is associated with anisotropy in hydrogen reactions within the fiber. As a result they lead, through known mechanisms of dilation in glass, to anisotropic stress relaxation that can be annealed out, with or without hydrogen...

Hydrogen abstraction reactions by amide electron adducts

International Nuclear Information System (INIS)

Sevilla, M.D.; Sevilla, C.L.; Swarts, S.

1982-01-01

Electron reactions with a number of peptide model compounds (amides and N-acetylamino acids) in aqueous glasses at low temperature have been investigated using ESR spectroscopy. The radicals produced by electron attachment to amides, RC(OD)NDR', are found to act as hydrogen abstracting agents. For example, the propionamide electron adduct is found to abstract from its parent propionamide. Electron adducts of other amides investigated show similar behavior except for acetamide electron adduct which does not abstract from its parent compound, but does abstract from other amides. The tendency toward abstraction for amide electron adducts are compared to electron adducts of several carboxylic acids, ketones, aldehydes and esters. The comparison suggests the hydrogen abstraction tendency of the various deuterated electron adducts (DEAs) to be in the following order: aldehyde DEA > acid DEA = approximately ester DEA > ketone DEA > amide DEA. In basic glasses the hydrogen abstraction ability of the amide electron adducts is maintained until the concentration of base is increased sufficiently to convert the DEA to its anionic form, RC(O - )ND 2 . In this form the hydrogen abstracting ability of the radical is greatly diminished. Similar results were found for the ester and carboxylic acid DEA's tested. (author)

Sol-Gel Glasses

Science.gov (United States)

Mukherjee, S. P.

1985-01-01

Multicomponent homogeneous, ultrapure noncrystalline gels/gel derived glasses are promising batch materials for the containerless glass melting experiments in microgravity. Hence, ultrapure, homogeneous gel precursors could be used to: (1) investigate the effect of the container induced nucleation on the glass forming ability of marginally glass forming compositions; and (2) investigate the influence of gravity on the phase separation and coarsening behavior of gel derived glasses in the liquid-liquid immiscibility zone of the nonsilicate systems having a high density phase. The structure and crystallization behavior of gels in the SiO2-GeO2 as a function of gel chemistry and thermal treatment were investigated. As are the chemical principles involved in the distribution of a second network former in silica gel matrix being investigated. The procedures for synthesizing noncrystalline gels/gel-monoliths in the SiO2-GeO2, GeO2-PbO systems were developed. Preliminary investigations on the levitation and thermal treatment of germania silicate gel-monoliths in the Pressure Facility Acoustic Levitator were done.

International Congress on Glass XII

Energy Technology Data Exchange (ETDEWEB)

Doremus, R H; LaCourse, W C; Mackenzie, J D; Varner, J R; Wolf, W W [eds.

1980-01-01

A total of 158 papers are included under nine headings: structure and glass formation; optical properties; electrical and magnetic properties; mechanical properties and relaxation; mass transport; chemical durability and surfaces; nucleation; crystallization; and glass ceramics; processing; and automatic controls. Separate abstracts were prepared for eight papers; four of the remaining papers had been processed previously for the data base. (DLC)

Kinetic arrest and glass-glass transition in short-ranged attractive colloids

International Nuclear Information System (INIS)

Sztucki, M.; Narayanan, T.; Belina, G.; Moussaied, A.; Pignon, F.; Hoekstra, H.

2006-01-01

A thermally reversible repulsive hard-sphere to sticky-sphere transition was studied in a model colloidal system over a wide volume fraction range. The static microstructure was obtained from high resolution small angle x-ray scattering, the colloid dynamics was probed by dynamic x-ray and light scattering, and supplementary mechanical properties were derived from bulk rheology. At low concentration, the system shows features of gas-liquid type phase separation. The bulk phase separation is presumably interrupted by a gelation transition at the intermediate volume fraction range. At high volume fractions, fluid-attractive glass and repulsive glass-attractive glass transitions are observed. It is shown that the volume fraction of the particles can be reliably deduced from the absolute scattered intensity. The static structure factor is modeled in terms of an attractive square-well potential, using the leading order series expansion of Percus-Yevick approximation. The ensemble-averaged intermediate scattering function shows different levels of frozen components in the attractive and repulsive glassy states. The observed static and dynamic behavior are consistent with the predictions of a mode-coupling theory and numerical simulations for a square-well attractive system

Solubility and diffusivity of hydrogen in complex materials

International Nuclear Information System (INIS)

Kirchheim, R.

2001-01-01

A general model based on Statistical Mechanics and Random Walk is presented which allows to describe the behavior of hydrogen in disordered systems, i.e. metallic glasses, amorphous silicon, nanocrystalline metals, deformed metals, disordered metallic solutions, and metallic multi layers. The various systems are specified by a lattice with an appropriate site energy disorder and a distribution of site transitions rates. Lattice sites are filled according to Fermi-Dirac Statistics because double occupancy is excluded. Thus the model is applicable to adsorption on heterogeneous surfaces or solutions of small particles in oxide glasses and polymers. With a given distribution of site energies a relationship between chemical potential (Fermi energy) of hydrogen and its concentration can be derived and compared with experimental results. It is a unique feature of hydrogen that its chemical potential and its diffusion coefficient can be determined rather easily by electrochemical techniques or by measuring partial pressures at moderate temperatures around 300 K. With increasing H-content the sites are usually filled from lower to higher energies. As a consequence Henry's Law is not fulfilled and the diffusion coefficient increases because at high concentrations low energy sites are saturated and additional H-atoms have to perform their random walk through sites of low occupancy or small time of residence, respectively. Some results for metallic glasses, nanocrystalline metals, deformed metals, and metallic multi layers are presented and compared with the model. Thus information on the interaction between defects (dislocations, grain boundaries, distorted tetrahedral sites in glasses) and hydrogen are obtained. For extended defects the diffusion is strongly anisotropic, i.e. it differs in a Pd/Nb-multi layer by a factor of 10 5 for diffusion in plane and out of plane. (orig.)

Preparation and characterization of a nickel/alumina composite membrane for high temperature hydrogen separation. Application in a membrane reactor for the dry reforming of methane; De la synthese d'une membrane composite nikel/ceramique permselective a l'hydrogene au reacteur membranaire. Application au reformage du methane

Energy Technology Data Exchange (ETDEWEB)

Haag, St.

2003-11-01

The objective of this work was to develop composite inorganic membranes based on nickel or palladium supported on a porous ceramic for high temperature hydrogen separation. These membranes were used in a membrane reactor for the dry reforming of methane in order to shift the chemical equilibrium towards the production of hydrogen and carbon monoxide. The metal layers were deposited on a tubular alumina support by electroless plating. The Ni and the Pd layers are 1 micron thick. The hydrogen permeation tests were done for high temperatures. The Pd/ceramic membrane is permselective to hydrogen and the H{sub 2}/N{sub 2} separation factor (single gas) is 60 at 400 deg C with a transmembrane pressure difference of 1 bar. With a gas mixture, the H{sub 2}/N{sub 2} separation factor is 13. This membrane is not completely dense and the transport mechanism of hydrogen through the Pd layer is mixed: solution-diffusion through the metal bulk and surface diffusion through the defects of the film. However, an embrittlement of the palladium layer under hydrogen atmosphere was observed at 500 deg C. The Ni/ceramic membrane is stable until 600 deg C, its permselectivity to hydrogen increases with the temperature. The use of a sweep gas can provide a H{sub 2}/N{sub 2} separation factor (mixture) of about 25. The main diffusion mechanism is surface diffusion through the pores. Both membranes are not catalytic. Thus, some catalysts composed of nickel and cobalt supported on MgO, SiO{sub 2} or Al{sub 2}O{sub 3} were prepared. These systems allow to reach theoretical limits of conversion calculated for a conventional fixed bed reactor. In the membrane reactor, an enhancement of the methane conversion (15-20%) is observed with both membranes due the selective removal of hydrogen during the reaction. The Ni/ceramic membrane more stable, more permeable and as selective as the palladium one is a brand new material for high temperature hydrogen separation. (author)

Study of the bipolar electrolysis of the tritiated water applied to the hydrogen isotopes separation by electrochemical permeation threw Pd-Ag alloy membranes

International Nuclear Information System (INIS)

Heinze, S.

2000-01-01

The objective of the study is to enrich waters of poor tritium concentration, by electrolysis in the same time of an hydrogen emission of low activity. In this framework the hydrogen electrochemical permeation threw Pd-Ag alloy membranes has been used. The first part of the study concerns the hydrogen and the deuterium diffusion threw these membranes. The activation and the thermal treatments influence have been studied. A relation between the membrane microstructure and the diffusion mechanism has been proposed. The second part of the study is devoted to the hydrogen gate mechanism determination in the membrane by impedance spectroscopy. The last part concerns the determination of the isotopic separation factor hydrogen-deuterium. Experimental results agree the calculated theoretical data. The operation of an operational membrane cell has been simulated and the process feasibility has been proved. (A.L.B.)

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.

Hydrogen-metal systems

International Nuclear Information System (INIS)

Wenzl, H.; Springer, T.

1976-01-01

A survey is given on the alloys of metal crystals with hydrogen. The system niobium-hydrogen and its properties are especially dealt with: diffusion and heat of solution of hydrogen in the host crystal, phase diagram, coherent and incoherent phase separation, application of metal-hydrogen systems in technology. Furthermore, examples from research work in IFF (Institut fuer Festkoerperforschung) of the Nuclear Research Plant, Juelich, in the field of metal-H systems are given in summary form. (GSC) [de

Dedusting in the glass industry; Depoussierage en verrerie

Energy Technology Data Exchange (ETDEWEB)

Tackels, G. [Saint-Gobain Concetpions Verrieres (France); Depauw, J.P. [Procedair (France); Myrope, A. [Lurgi (France)

2000-07-01

Here are gathered several articles concerning the dedusting in the glass industry. At present, about a third of the European glass furnaces are fitted out with filters. The best industrially available techniques used for the abatement of glass dust releases are: handle filters and electro-filters. Their principles of separation, characteristics of manufacturing and performance are detailed. (O.M.)

Separation of tritium from gaseous and aqueous effluent systems

International Nuclear Information System (INIS)

Kobisk, E.H.

1977-01-01

Removal or reduction of tritium content in a wide variety of effluent streams has been extensively studied in the United States. This paper specifically reviews three processes involving tritium separation in the gaseous phase and the aqueous phase. Diffusion through a selective Pd-25Ag alloy membrane at temperatures up to 600 0 C and at pressures up to 700 kg/cm 2 has resulted in successful separation of hydrogen-deuterium mixtures with an associated separation factor of 1.65 (and gives a calculated separation factor for hydrogen-tritium mixtures of 2.0). Use of a single palladium bipolar membrane in an electrolysis system has been found to yield a hydrogen-deuterium separation factor of 4 and a hydrogen-tritium factor of 6 to 11 without the production of gaseous hydrogen. Finally, countercurrent catalytic exchange between tritium-containing hydrogen gas and water has yielded a separation factor of 6.3. The specific advantages of each of these systems will be discussed in terms of their potential applications. In all cases, further investigations are necessary to scale the systems to handle large quantities of feed material in a continuous mode and to minimize energy requirements. Such separative systems must necessarily be cascaded to yield gaseous or aqueous product streams suitable for recycling to the tritium producing systems, for storage or for discharge to the environment. (orig./HP) [de

Glasses, ceramics, and composites from lunar materials

Science.gov (United States)

Beall, George H.

1992-01-01

A variety of useful silicate materials can be synthesized from lunar rocks and soils. The simplest to manufacture are glasses and glass-ceramics. Glass fibers can be drawn from a variety of basaltic glasses. Glass articles formed from titania-rich basalts are capable of fine-grained internal crystallization, with resulting strength and abrasion resistance allowing their wide application in construction. Specialty glass-ceramics and fiber-reinforced composites would rely on chemical separation of magnesium silicates and aluminosilicates as well as oxides titania and alumina. Polycrystalline enstatite with induced lamellar twinning has high fracture toughness, while cordierite glass-ceramics combine excellent thermal shock resistance with high flexural strengths. If sapphire or rutile whiskers can be made, composites of even better mechanical properties are envisioned.

Interaction of atomic hydrogen with ethylene adsorbed on nickel films

International Nuclear Information System (INIS)

Korchak, V.N.; Tret'yakov, I.I.; Kislyuk, M.U.

1976-01-01

The reactivity of ethylene adsorbed on the pure films of nickel at various temperatures was studied with respect to hydrogen atoms generated in the gaseous phase. The experiments were conducted in a glass vacuum apparatus enabling one to obtain the highest vacuum up to 2x20 -10 torr. The catalyst, nickel films, was produced by their deposition onto the walls of the glass reactor at a pressure of the residual gas of 10 -9 torr and a temperature of the walls of 25 deg C. Gas purity was analyzed by the mass spectrometric method. The ethylene adsorbed at the temperatures below 173 deg K reacted readily with the hydrogen atoms to yield ethane. The process ran without practically any activation energy involved and was limited by the attachment of the first hydrogen atom to the ethylene molecule. The efficiency of this interaction was 0.02 of the number of the hydrogen atoms collisions against the surface occupied by the ethylene. The adsorption of the ethylene at room and higher temperatures was accompanied by its disproportioning with the release of the hydrogen into the gaseous phase and a serious destruction of the ethylene molecules adsorbed to produce hydrogen residues interacting with neither molecular nor atomic hydrogen [ru

The structure of phosphate and borosilicate glasses and their structural evolution at high temperatures as studied with solid state NMR spectroscopy: Phase separation, crystallisation and dynamic species exchange

International Nuclear Information System (INIS)

Wegner, S.; Van Wullen, L.; Tricot, G.; Tricot, G.

2010-01-01

In this contribution we present an in-depth study of the network structure of different phosphate based and borosilicate glasses and its evolution at high temperatures. Employing a range of advanced solid state NMR methodologies, complemented by the results of XPS, the structural motifs on short and intermediate length scales are identified. For the phosphate based glasses, at temperatures above the glass transition temperature Tg, structural relaxation processes and the devitrification of the glasses were monitored in situ employing MAS NMR spectroscopy and X-ray diffraction. Dynamic species exchange involving rapid P-O-P and P-O-Al bond breaking and reforming was observed employing in situ 27 Al and 31 P MAS NMR spectroscopy and could be linked to viscous flow. For the borosilicate glasses, an atomic scale investigation of the phase separation processes was possible in a combined effort of ex situ NMR studies on glass samples with different thermal histories and in situ NMR studies using high temperature MAS NMR spectroscopy including 11 B MAS, 29 Si MAS and in situ 29 Si{ 11 B} REAPDOR NMR spectroscopy. (authors)

Hydrogen permeation resistant phosphate coatings

International Nuclear Information System (INIS)

McGuire, J.C.

1979-01-01

A method for reducing hydrogen diffusion through metal wherein the metal is coated with a phosphate-radical-containing, phosphate-glass-forming material on at least one surface thereof. The coating is then heated to at least 350 0 C to form a phosphate glass. This method is especially applicable to nuclear reactors to minimize tritium diffusion. The coating is preferably formed with a solution of phosphoric acid which may also contain compounds such as MnSO 4 , SiO 2 and Na 2 Cr 2 0 7 . (author)

Hydrogen permeation resistant phosphate coatings

International Nuclear Information System (INIS)

McGuire, J.C.

1979-01-01

A method for reducing hydrogen diffusion through metal is described. The metal is coated with a phosphate-radical-containing, phosphate-glass-forming material on at least one surface. The coating is then heated to at least 350 0 C to form a phosphate glass. This method is especially applicable to nuclear reactors to minimize tritium diffusion. The coating is preferably formed with a solution of phosphoric acid which may also contain compounds such as MnSO 4 , SiO 2 and Na 2 Cr 2 O 7 . (author)

Recovery of high-purity hydrogen from COG

Energy Technology Data Exchange (ETDEWEB)

Tsukiyama, Y

1982-01-01

A general account of the latest trends in the recovery of high-purity hydrogen from coke oven gas (COG), the article being based on both Japanese and overseas literature: 1) Deep-freeze separation: impurities are liquefied and removed. This method make use of the fact that hydrogen is hard to liquefy. 2) The PSA method: high-purity hydrogen is recovered by the adsorption of other constituents at high pressures. This technique makes use of the fact that the adsorption capacity of an adsorbent varies with the partial pressure of the substances being adsorbed. 3) Membrane separation: a permeation separation method that uses a functional polymer separation membrane, and that depends on the fact that hydrogen has a low molecular weight in comparison with the other constituents. (19 refs.) (In Japanese)

Structural isotopic effect of the α/β-phase transition in the vanadium hydride and its influence on the equilibrium coefficient of separation of hydrogen isotopes in the gas-solid system

International Nuclear Information System (INIS)

Magomedbekov, Eh.P.; Bochkarev, A.V.

1999-01-01

Equilibrium coefficient of hydrogen isotope separation (α H-D ) in the system of vanadium hydride VH n (solid, n ∼ 0.7)-H 2 (g) is measured by the counterbalancing method in a circulation facility and by the method of laser desorption at 298, 373, and 437 K. It is shown that the combination of highly anharmonic potential in the lattice octahedral sites and in significant difference in the energy of hydrogen atom coordination for tetra- and octahedral sites is the reason for unusual behaviour of the hydrogen isotope separation coefficient and the difference in crystal structures of vanadium hydride and deuteride [ru

Super ionic conductive glass

Science.gov (United States)

Susman, S.; Volin, K.J.

Described is an ionically conducting glass for use as a solid electrolyte in a power or secondary cell containing an alkali metal-containing anode and a cathode separated by an alkali metal ion conducting glass having an ionic transference number of unity and the general formula: A/sub 1 + x/D/sub 2-x/3/Si/sub x/P/sub 3 - x/O/sub 12 - 2x/3/, wherein A is a network modifier for the glass and is an alkali metal of the anode, D is an intermediate for the glass and is selected from the class consisting of Zr, Ti, Ge, Al, Sb, Be, and Zn and X is in the range of from 2.25 to 3.0. Of the alkali metals, Na and Li are preferred and of the intermediate, Zr, Ti and Ge are preferred.

System efficiency for two-step metal oxide solar thermochemical hydrogen production – Part 2: Impact of gas heat recuperation and separation temperatures

KAUST Repository

Ehrhart, Brian D.; Muhich, Christopher L.; Al-Shankiti, Ibraheam; Weimer, Alan W.

2016-01-01

. The hydrogen and water separation temperature was also varied and the effect on STH efficiency quantified. This study shows that gas heat recuperation is critical for high efficiency cycles, especially at conditions that require high steam and inert gas

Interactions between the glass fiber coating and oxidized carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Ku-Herrera, J.J., E-mail: jesuskuh@live.com.mx [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburná de Hidalgo. C.P., 97200 Mérida, Yucatán (Mexico); Avilés, F., E-mail: faviles@cicy.mx [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburná de Hidalgo. C.P., 97200 Mérida, Yucatán (Mexico); Nistal, A. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain); Cauich-Rodríguez, J.V. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburná de Hidalgo. C.P., 97200 Mérida, Yucatán (Mexico); Rubio, F.; Rubio, J. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain); Bartolo-Pérez, P. [Departamento de Física Aplicada, Cinvestav, Unidad Mérida, C.P., 97310 Mérida, Yucatán (Mexico)

2015-03-01

Graphical abstract: - Highlights: • Oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto E-glass fibers. • The role of the fiber coating on the deposition of MWCNTs on the fibers is studied. • A rather homogeneous deposition of MWCNTs is achieved if the coating is maintained. • Multiple oxygen-containing groups were found in the analysis of the fiber coating. • Evidence of chemical interaction between MWCNTs and the fiber coating was found. - Abstract: Chemically oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto commercial E-glass fibers using a dipping procedure assisted by ultrasonic dispersion. In order to investigate the role of the fiber coating (known as “sizing”), MWCNTs were deposited on the surface of as-received E-glass fibers preserving the proprietary coating as well as onto glass fibers which had the coating deliberately removed. Scanning electron microscopy and Raman spectroscopy were used to assess the distribution of MWCNTs onto the fibers. A rather homogeneous coverage with high density of MWCNTs onto the glass fibers is achieved when the fiber coating is maintained. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) analyses of the chemical composition of the glass fiber coating suggest that such coating is a complex mixture with multiple oxygen-containing functional groups such as hydroxyl, carbonyl and epoxy. FTIR and XPS of MWCNTs over the glass fibers and of a mixture of MWCNTs and fiber coating provided evidence that the hydroxyl and carboxyl groups of the oxidized MWCNTs react with the oxygen-containing functional groups of the glass fiber coating, forming hydrogen bonding and through epoxy ring opening. Hydrogen bonding and ester formation between the functional groups of the MWCNTs and the silane contained in the coating are also possible.

Interactions between the glass fiber coating and oxidized carbon nanotubes

International Nuclear Information System (INIS)

Ku-Herrera, J.J.; Avilés, F.; Nistal, A.; Cauich-Rodríguez, J.V.; Rubio, F.; Rubio, J.; Bartolo-Pérez, P.

2015-01-01

Graphical abstract: - Highlights: • Oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto E-glass fibers. • The role of the fiber coating on the deposition of MWCNTs on the fibers is studied. • A rather homogeneous deposition of MWCNTs is achieved if the coating is maintained. • Multiple oxygen-containing groups were found in the analysis of the fiber coating. • Evidence of chemical interaction between MWCNTs and the fiber coating was found. - Abstract: Chemically oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto commercial E-glass fibers using a dipping procedure assisted by ultrasonic dispersion. In order to investigate the role of the fiber coating (known as “sizing”), MWCNTs were deposited on the surface of as-received E-glass fibers preserving the proprietary coating as well as onto glass fibers which had the coating deliberately removed. Scanning electron microscopy and Raman spectroscopy were used to assess the distribution of MWCNTs onto the fibers. A rather homogeneous coverage with high density of MWCNTs onto the glass fibers is achieved when the fiber coating is maintained. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) analyses of the chemical composition of the glass fiber coating suggest that such coating is a complex mixture with multiple oxygen-containing functional groups such as hydroxyl, carbonyl and epoxy. FTIR and XPS of MWCNTs over the glass fibers and of a mixture of MWCNTs and fiber coating provided evidence that the hydroxyl and carboxyl groups of the oxidized MWCNTs react with the oxygen-containing functional groups of the glass fiber coating, forming hydrogen bonding and through epoxy ring opening. Hydrogen bonding and ester formation between the functional groups of the MWCNTs and the silane contained in the coating are also possible

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)

Analysis of Gas Separated for Silica Membrane in Hydrogen Gas Production by Using Nuclear Reactor Thermal

International Nuclear Information System (INIS)

Pandiangan, Tumpal

2007-01-01

One of the hydrogen production method that have been developed is a thermo-chemical method. This method is permissible to increase thermal efficiency up to 70 % and to decrease of operational temperature from 800℃ down to 450 ℃. One of several factor that can increase of the hydrogen production thermal efficiency at the above method is to apply a separated membrane that have a relative good for permeansce and selectivity performance. It had been carried out for analyzing of time and temperature CVD (Chemical Vapouration Deposition) that is affected to permeansce and power selecting performance of the membrane. The layering membrane silica process was carried out by means of the CVD method at atmosphere pressure. The membrane silica layering that was observed was developed by a CVD method in atmospheric pressure. The silica membrane was formed at the out side surface of the alumina gamma cylinder that had been coated by alumina gamma which it has average porosity about of 0.01 mic.meter. A permeansce and separation power performance of the membrane silica that was carried out by means of CVD method at 600 ℃ on H 2 , He and N 2 are : 2 x 10 -10 , 9 x 10 -9 and 4 x 10 -7 mol Pa/m 2 s and the selected power of H 2 /N 2 = 45. The permeansce of that membrane is relative good but the selected power is relative not so good. (author)

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.

The Separation of Hydrogen Tritium and Tritium Hydride by Gas Chromatography; Separation de l'hydrogene, du tritium et de l'hydrure de tritium par chromatographic en phase gazeuse; Razdelenie vodoroda, tritiya i gidrida tritiya posredstvom gazovoj khromatografii; Separacion del hidrogeno, tritio e hidruro de tritio por cromatografia de gases

Energy Technology Data Exchange (ETDEWEB)

Smith, H A; Carter, Jr, E H [University of Tennessee, Knoxville, TN (United States)

1962-01-15

Now that successful separation of hydrogen, deuterium and hydrogen deuteride has been achieved by gas chromatography, similar studies are being made dealing with mixtures of hydrogen, tritium and tritium hydride. Since tritium is used in tracer quantities the usual katharometer cannot be employed for its detection. This difficulty has been overcome by providing immediately following the katharometer a vibrating reed electrometer equipped with a high resistance leak which allows continuous monitoring of the activity of any tritium or tritium hydride emerging from the column by means of synchronized recorders. Separation of such mixtures has been tested with columns packed with palladium on silica, silica, alumina, and alumina coated with chromium oxide or ferric oxide. No effective separation was obtained with the palladium on silica column. Good separation was achieved with the plain silica column where hydrogen was employed as the carrier gas, but helium failed to elute the isotopes. Satisfactory results were obtained with the coated, partially deactivated alumina packing when helium or neon was the carrier gas, but the best separation was found with a column packing of uncoated activated alumina. Calibration with helium-tritium mixtures of known activity plus equilibrated hydrogen-tritium mixtures also of known activity allows quantitative estimation of tritium and tritium hydride. (author) [French] La separation de l'hydrogene, du deuterium et du deuterure d'hydrogene par chromatographic en phase gazeuse ayant ete realisee, on procede maintenant a des etudes semblables sur des melanges d'hydrogene de tritium et d'hydrure de tritium. Comme le tritium n'est present qu'en quantites infimes, on ne peut utiliser le catharometre ordinaire pour le detecter. On a surmonte cette difficulte en faisant suivre le catharometre d'un electrometre a lame vibrante, muni d'une fuite haute resistance, qui permet de mesurer, a l'aide d'enregistreurs synchronises, l'activite de

Optimization of separate hydrogen and methane production from cassava wastewater using two-stage upflow anaerobic sludge blanket reactor (UASB) system under thermophilic operation.

Science.gov (United States)

Intanoo, Patcharee; Rangsanvigit, Pramoch; Malakul, Pomthong; Chavadej, Sumaeth

2014-12-01

The objective of this study was to investigate the separate hydrogen and methane productions from cassava wastewater by using a two-stage upflow anaerobic sludge blanket (UASB) system under thermophilic operation. Recycle ratio of the effluent from methane bioreactor-to-feed flow rate was fixed at 1:1 and pH of hydrogen UASB unit was maintained at 5.5. At optimum COD loading rate of 90 kg/m3 d based on the feed COD load and hydrogen UASB volume, the produced gas from the hydrogen UASB unit mainly contained H2 and CO2 which provided the maximum hydrogen yield (54.22 ml H2/g COD applied) and specific hydrogen production rate (197.17 ml/g MLVSSd). At the same optimum COD loading rate, the produced gas from the methane UASB unit mainly contained CH4 and CO2 without H2 which were also consistent with the maximum methane yield (164.87 ml CH4/g COD applied) and specific methane production rate (356.31 ml CH4/g MLVSSd). The recycling operation minimized the use of NaOH for pH control in hydrogen UASB unit. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effect of liquid phase separation on the Vickers microindentation shear bands evolution in a Fe-based bulk metallic glass

Energy Technology Data Exchange (ETDEWEB)

Askari-Paykani, M. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, North Kargar Street, Tehran 11356-4563 (Iran, Islamic Republic of); Nili Ahmadabadi, M., E-mail: nili@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, North Kargar Street, Tehran 11356-4563 (Iran, Islamic Republic of); Center of Excellence for High Performance Materials, School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Seiffodini, A. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, North Kargar Street, Tehran 11356-4563 (Iran, Islamic Republic of); Yazd University, Department of Material Science and Engineering, Yazd 84196 (Iran, Islamic Republic of)

2013-11-15

The Vickers microindentation experiments and associated plastic deformation in as-cast and annealed (Fe{sub 0.9}Ni{sub 0.1}){sub 77}Mo{sub 5}P{sub 9}C{sub 7.5}B{sub 1.5} bulk metallic glass was conducted. In addition to the bulk indentation behavior, the shear band morphology underneath the Vickers microindenter was examined by employing the bonded interface technique. Microstructural characterization revealed that a liquid phase separation occurred during melting process. Atomic force microscopy of the glassy matrix of the as-cast specimen reveals the composition inhomogeneity induced by the liquid phase separation. This effect generates shear band branching or deflection during the shear band propagation. For the bulk indentation, the trends in the hardness vs. indentation load were found related to the pressure sensitive index and the phase separation process simultaneously. The results show that the as-cast as well as the annealed specimens are deformed through semi-circular and radial shear bands. In addition, in the partially crystalized specimen, the change in the properties and microstructure of the BMG induced by the partial crystallization treatment and phase separation process resulted in tertiary shear bands formation.

Separating hydrogen and oxygen evolution in alkaline water electrolysis using nickel hydroxide

Science.gov (United States)

Chen, Long; Dong, Xiaoli; Wang, Yonggang; Xia, Yongyao

2016-01-01

Low-cost alkaline water electrolysis has been considered a sustainable approach to producing hydrogen using renewable energy inputs, but preventing hydrogen/oxygen mixing and efficiently using the instable renewable energy are challenging. Here, using nickel hydroxide as a redox mediator, we decouple the hydrogen and oxygen production in alkaline water electrolysis, which overcomes the gas-mixing issue and may increase the use of renewable energy. In this architecture, the hydrogen production occurs at the cathode by water reduction, and the anodic Ni(OH)2 is simultaneously oxidized into NiOOH. The subsequent oxygen production involves a cathodic NiOOH reduction (NiOOH→Ni(OH)2) and an anodic OH− oxidization. Alternatively, the NiOOH formed during hydrogen production can be coupled with a zinc anode to form a NiOOH-Zn battery, and its discharge product (that is, Ni(OH)2) can be used to produce hydrogen again. This architecture brings a potential solution to facilitate renewables-to-hydrogen conversion. PMID:27199009

Dynamic and thermodynamic characteristics associated with the glass transition of amorphous trehalose-water mixtures.

Science.gov (United States)

Weng, Lindong; Elliott, Gloria D

2014-06-21

The glass transition temperature Tg of biopreservative formulations is important for predicting the long-term storage of biological specimens. As a complementary tool to thermal analysis techniques, which are the mainstay for determining Tg, molecular dynamics simulations have been successfully applied to predict the Tg of several protectants and their mixtures with water. These molecular analyses, however, rarely focused on the glass transition behavior of aqueous trehalose solutions, a subject that has attracted wide scientific attention via experimental approaches. Important behavior, such as hydrogen-bonding dynamics and self-aggregation has yet to be explored in detail, particularly below, or in the vicinity of, Tg. Using molecular dynamics simulations of several dynamic and thermodynamic properties, this study reproduced the supplemented phase diagram of trehalose-water mixtures (i.e., Tg as a function of the solution composition) based on experimental data. The structure and dynamics of the hydrogen-bonding network in the trehalose-water systems were also analyzed. The hydrogen-bonding lifetime was determined to be an order of magnitude higher in the glassy state than in the liquid state, while the constitution of the hydrogen-bonding network exhibited no noticeable change through the glass transition. It was also found that trehalose molecules preferred to form small, scattered clusters above Tg, but self-aggregation was substantially increased below Tg. The average cluster size in the glassy state was observed to be dependent on the trehalose concentration. Our findings provided insights into the glass transition characteristics of aqueous trehalose solutions as they relate to biopreservation.

Process chemistry related to hydrogen isotopes

International Nuclear Information System (INIS)

Iwasaki, Matae; Ogata, Yukio

1991-01-01

Hydrogen isotopes, that is, protium, deuterium and tritium, are all related deeply to energy in engineering region. Deuterium and tritium exist usually as water in extremely thin state. Accordingly, the improvement of the technology for separating these isotopes is a large engineering subject. Further, tritium is radioactive and its half-life period is 12.26 years, therefore, it is desirable to fix it in more stable form besides its confinement in the handling system. As the chemical forms of hydrogen, the molecular hydrogen with highest reactivity, metal hydride, carbon-hydrogen-halogen system compounds, various inorganic hydrides, most stable water and hydroxides are enumerated. The grasping of the behavior from reaction to stable state of these hydrogen compounds and the related materials is the base of process chemistry. The reaction of exchanging isotopes between water and hydrogen on solid catalyzers, the decomposition of ethane halide containing hydrogen, the behavior of water and hydroxides in silicates are reported. The isotope exchange between water and hydrogen is expected to be developed as the process of separating and concentrating hydrogen isotopes. (K.I.) 103 refs

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.

The separation and recovery of hydrogen from the recycling gas in ammonia production by means of lanthanum-rich mischmetal nickel hydride beds

International Nuclear Information System (INIS)

Qidong, W.; Jing, W.; Changpin, C.; Weifang, L.

1985-01-01

The separation and recovery of hydrogen by means of a MlNi/sub 5/ (Ml: La-rich mischmetal) beds were studied. The influence of the impurity gas components (O/sub 2/, H/sub 2/O, N/sub 2/, Ar, CH/sub 4/ and NH/sub 3/ etc) on the hydrogen absorption capacity, hydriding and dehydriding kinetics and cycling ageing stability of the beds was investigated for both stagnant gases and continuously flowing gas streams. In small reactors, at first artificially made gas mixtures and finally the actual recycling gas from ammonia production were tested. In the presence of trace ammonia (<100ppm) in recycling gas stream, the efficiency of recovery amounted to 85 - 93% and the purity of the product hydrogen was around 99.9%. When ammonia amounted to 2.5%, the efficiency of recovery decreased to 81 - 86%. The hydrogen absorption capacity of the alloy bed remained unchanged after cycling 50 times, indicating the stability of the alloy satisfactory

Chemical states of molybdenum in radioactive waste glass

International Nuclear Information System (INIS)

Ishiguro, Katsuhiko; Kawanishi, Nobuo; Nagaki, Hiroshi; Naito, Aritsune

1982-01-01

In order to confirm an expectation that the chemical state of molybdenum in glass reflects the phase separation tendency of the yellow solid from the melt of borosilicate glass, simulated waste glasses were prepared, and ESCA analysis was performed using a commercially available electron spectrometer (PHI550 E) with an excitation source consisting of Mg Kα-ray. The effects of the concentration of Mo and FE 2 O 3 and the melting atmosphere (oxidizing or reducing) in which the samples were prepared on the chemical state of Mo and the solubility of MoO 3 were examined. From the observation of Mo spectra, it was shown that Mo in waste glass had several valencies, e.g., Mo(3), Mo(4), Mo(5) and Mo(6), while Mo in the yellow solid separated from the melts exhibited hexa-valent state, the peak intensity of higher valencies increased relatively with the increase of MoO 3 concentration, but the chemical state of Mo did not change remarkably around the solubility limit of MoO 3 , the melting atmosphere influenced on the Mo state in the waste glass, the peak intensity of Mo(6) increased relatively with the increasing Fe 2 O 3 concentration, and Mo in devitrified glass exhibited hexa-valent state. (Yoshitake, I.)

Preparation of special purity Ge - S - I and Ge - Se - I glasses

Science.gov (United States)

Velmuzhov, A. P.; Sukhanov, M. V.; Shiryaev, V. S.; Kotereva, T. V.; Snopatin, G. E.; Churbanov, M. F.

2017-05-01

The paper considers the new approaches for the production of special pure Ge - S - I and Ge - Se - I glasses via the germanium(IV) iodide, germanium(II) sulfide, as well as the Ge2S3, Ge2S3I2 and Ge2Se3I2 glassy alloys. The glass samples containing 0.03-0.17 ppm(wt) hydrogen impurity in the form of SH-group, 0.04-0.15 ppm(wt) hydrogen impurity in the form of SeH-group, and 0.5-7.8 ppm(wt) oxygen impurity in the form of Ge-O were produced. Using a crucible technique, the single-index [GeSe4]95I5 glass fibers of 300-400 μm diameter were drawn. The minimum optical losses in the best fiber were 1.7 dB/m at a wavelength of 5.5 μm; the background optical losses were within 2-3 dB/m in the spectral range of 2.5-8 μm.

Tritium removal by hydrogen isotopic exchange between hydrogen gas and water on hydrophobic catalyst

International Nuclear Information System (INIS)

Morishita, T.; Isomura, S.; Izawa, H.; Nakane, R.

1980-01-01

Many kinds of the hydrophobic catalysts for hydrogen isotopic exchange between hydrogen gas and water have been prepared. The carriers are the hydrophobic organic materials such as polytetrafluoroethylene(PTFE), monofluorocarbon-PTFE mixture(PTFE-FC), and styrene-divinylbenzene copolymer(SDB). 0.1 to 2 wt % Pt is deposited on the carriers. The Pt/SDB catalyst has much higher activity than the Pt/PTFE catalyst and the Pt/PTFE-FC catalyst shows the intermediate value of catalytic activity. The observation of electron microscope shows that the degrees of dispersion of Pt particles on the hydrophobic carriers result in the difference of catalytic activities. A gas-liquid separated type column containing ten stages is constructed. Each stage is composed of both the hydrophobic catalyst bed for the hydrogen gas/water vapor isotopic exchange and the packed column type bed for the water vapor/liquid water isotopic exchange. In the column hydrogen gas and water flow countercurrently and hydrogen isotopes are separated

The corrosion behavior of DWPF glasses

International Nuclear Information System (INIS)

Ebert, W.L.; Bates, J.K.

1995-01-01

The authors analyzed the corroded surfaces of reference glasses developed for the Defense Waste Processing Facility (DWPF) to characterize their corrosion behavior. The corrosion mechanism of nuclear waste glasses must be known in order to provide source terms describing radionuclide release for performance assessment calculations. Different DWPF reference glasses were corroded under conditions that highlighted various aspects of the corrosion process and led to different extents of corrosion. The glasses corroded by similar mechanisms, and a phenomenological description of their corrosion behavior is presented here. The initial leaching of soluble glass components results in the formation of an amorphous gel layer on the glass surface. The gel layer is a transient phase that transforms into a layer of clay crystallites, which equilibrates with the solution as corrosion continues. The clay layer does not act as a barrier to either water penetration or glass dissolution, which continues beneath it, and may eventually separate from the glass. Solubility limits for glass components may be established by the eventual precipitation of secondary phases; thus, corrosion of the glass becomes controlled by the chemical equilibrium between the solution and the assemblage of secondary phases. In effect, the solution is an intermediate phase through which the glass transforms to an energetically more favorable assemblage of phases. Implications regarding the prediction of long-term glass corrosion behavior are discussed

Radiation effects on phase separation and viscosity of glasses

International Nuclear Information System (INIS)

Biron, I.; Barbu, A.

1987-06-01

The effect of electron irradiations on the stability of B 2 O 3P bO glasses is studied by transmission electron microscopy. Rapid coagulation of pure lead particles is observed. By using the Smoluchosky's coagulation theory, it is shown that the viscosity of B 2 O 3 is drastically reduced by several orders of magnitude under irradiation. The electron excitations are shown to play the dominant role in this phenomena

The role of sidestream recycle in hydrogen isotope separation and column cascade design

International Nuclear Information System (INIS)

Sherman, R.H.; Taylor, D.J.; Yamanishi, T.; Enoeda, M.; Konishi, S.; Okuno, K.

1994-01-01

Sidestream recycle combined with sidestream equilibration is important in hydrogen isotopic distillation processes because it offers a means to reduce the number of columns required for the extraction of pure homonuclear species. This directly implies simpler systems, reduced control problems, and reduce material inventories. Measurements were recently completed for a single distillation column using feed compositions (∼50--50 D-T) and product flows similar to those expected in an ITER type device wit recycle of an equilibrated sidestream withdrawn from the column. Dynamic studies were conducted with flowrates changing as might be expected for typical Tokamak operations. These experimental results are compared with computer simulations of the dynamic process. The impact of these sidestream recycle studies on the design of isotope separation systems is discussed, especially with respect to column design, tritium inventory, dynamic performance, stability, and system control

Direction of CRT waste glass processing: Electronics recycling industry communication

International Nuclear Information System (INIS)

Mueller, Julia R.; Boehm, Michael W.; Drummond, Charles

2012-01-01

Highlights: ► Given a large flow rate of CRT glass ∼10% of the panel glass stream will be leaded. ► The supply of CRT waste glass exceeded demand in 2009. ► Recyclers should use UV-light to detect lead oxide during the separation process. ► Recycling market analysis techniques and results are given for CRT glass. ► Academic initiatives and the necessary expansion of novel product markets are discussed. - Abstract: Cathode Ray Tube, CRT, waste glass recycling has plagued glass manufacturers, electronics recyclers and electronics waste policy makers for decades because the total supply of waste glass exceeds demand, and the formulations of CRT glass are ill suited for most reuse options. The solutions are to separate the undesirable components (e.g. lead oxide) in the waste and create demand for new products. Achieving this is no simple feat, however, as there are many obstacles: limited knowledge of waste glass composition; limited automation in the recycling process; transportation of recycled material; and a weak and underdeveloped market. Thus one of the main goals of this paper is to advise electronic glass recyclers on how to best manage a diverse supply of glass waste and successfully market to end users. Further, this paper offers future directions for academic and industry research. To develop the recommendations offered here, a combination of approaches were used: (1) a thorough study of historic trends in CRT glass chemistry; (2) bulk glass collection and analysis of cullet from a large-scale glass recycler; (3) conversations with industry members and a review of potential applications; and (4) evaluation of the economic viability of specific uses for recycled CRT glass. If academia and industry can solve these problems (for example by creating a database of composition organized by manufacturer and glass source) then the reuse of CRT glass can be increased.

Two-phase, passive separator-and-filter assembly

Science.gov (United States)

Erickson, A. C.; Porter, F. J., Jr.

1974-01-01

Assembly separates liquid from gas by passive hydrophilic/hydrophobic material approach. Apparatus is comprised of porous glass hydrophilic tubes. Quantity, lateral size, and pore size of glass tubes are determined by particular design requirements with regard to water rate, water quality contamination level, application endurance life, and operating differential pressure level.

Hydrogen isotope technology

International Nuclear Information System (INIS)

Anon.

1980-01-01

Hydrogen pumping speeds on panels of molecular sieve types 5A and Na-Y were compared for a variety of sieve (and chevron) temperatures between 10 and 30 K. Although pumping speeds declined with time, probably because of the slow diffusion of hydrogen from the surface of the sieve crystals into the internal regions, the different sieve materials and operating conditions could be compared using time-averaged pump speeds. The (average) pumping speeds declined with increasing temperature. Under some conditions, the Na-Y sieve performed much better than the 5A sieve. Studies of the effect of small concentrations (approx. 4%) of hydrogen on helium pumping indicate that compound cryopumps in fusion reactors will not have to provide complete screening of hydrogen from helium panels. The concentrations of hydrogen did not lower effective helium pumping speeds or shorten the helium operating period between instabilities. Studies of tritium recovery from blankets of liquid lithium focused on design and construction of a flowing-lithium test system and on ultimate removal of tritium from yttrium sorbents. At 505 0 C, tritium release from yttrium behaves as a diffusion-controlled process, but the release rates are very low. Apparently, higher temperatures will be required for effective sorbent regeneration. An innovative technique for separating hydrogen isotopes by using bipolar electrolysis with permeable electrodes was analyzed to determine its potential usefulness in multistage separation

Hydrogen isotope exchange reaction rates in tritium, hydrogen and deuterium mixed gases

International Nuclear Information System (INIS)

Uda, Tatsuhiko

1992-01-01

Hydrogen isotope exchange reaction rates in H 2 +T 2 , D 2 +T 2 and H 2 +D 2 +T 2 mixed gases, as induced by tritium decay and beta radiation, were experimentally measured by laser Raman spectrometry. Initially a glass cell was filled with T 2 gas to a pressure of 30-40 kPa, and an equivalent partial pressure of H 2 and/or D 2 was added. The first-order hydrogen isotope exchange reaction rates were 5.54x10 -2 h -1 for H 2 +T 2 mixed gas and 4.76x10 -2 h -1 for D 2 +T 2 . The actual HT producing rate was nearly equivalent to the rate of DT, but the reverse reaction rate of HT was faster than that of DT. The exchange reaction rates between H, D and T showed the isotope effect, HD>HT>DT. The hydrogen isotope exchange reaction rates observed were about twenty times larger than ion formation rates by beta radiation. This result suggests that a free radical chain reaction in hydrogen isotopes is occurring. (orig.)

Enhanced Hydrogen Production Integrated with CO2 Separation in a Single-Stage Reactor

Energy Technology Data Exchange (ETDEWEB)

Mahesh Iyer; Himanshu Gupta; Danny Wong; Liang-Shih Fan

2005-09-30

Hydrogen production from coal gasification can be enhanced by driving the equilibrium limited Water Gas Shift reaction forward by incessantly removing the CO{sub 2} by-product via the carbonation of calcium oxide. This project aims at using the OSU patented high-reactivity mesoporous precipitated calcium carbonate sorbent for removing the CO{sub 2} product. Preliminary experiments demonstrate the show the superior performance of the PCC sorbent over other naturally occurring calcium sorbents. Gas composition analyses show the formation of 100% pure hydrogen. Novel calcination techniques could lead to smaller reactor footprint and single-stage reactors that can achieve maximum theoretical H{sub 2} production for multicyclic applications. Sub-atmospheric calcination studies reveal the effect of vacuum level, diluent gas flow rate, thermal properties of the diluent gas and the sorbent loading on the calcination kinetics which play an important role on the sorbent morphology. Steam, which can be easily separated from CO{sub 2}, is envisioned to be a potential diluent gas due to its enhanced thermal properties. Steam calcination studies at 700-850 C reveal improved sorbent morphology over regular nitrogen calcination. A mixture of 80% steam and 20% CO{sub 2} at ambient pressure was used to calcine the spent sorbent at 820 C thus lowering the calcination temperature. Regeneration of calcium sulfide to calcium carbonate was achieved by carbonating the calcium sulfide slurry by bubbling CO{sub 2} gas at room temperature.

One Step Biomass Gas Reforming-Shift Separation Membrane Reactor

Energy Technology Data Exchange (ETDEWEB)

Roberts, Michael J. [Gas Technology Institute; Souleimanova, Razima [Gas Technology Institute

2012-12-28

GTI developed a plan where efforts were concentrated in 4 major areas: membrane material development, membrane module development, membrane process development, and membrane gasifier scale-up. GTI assembled a team of researchers to work in each area. Task 1.1 Ceramic Membrane Synthesis and Testing was conducted by Arizona State University (ASU), Task 1.2 Metallic Membrane Synthesis and Testing was conducted by the U.S. National Energy Technology Laboratory (NETL), Task 1.3 was conducted by SCHOTT, and GTI was to test all membranes that showed potential. The initial focus of the project was concentrated on membrane material development. Metallic and glass-based membranes were identified as hydrogen selective membranes under the conditions of the biomass gasification, temperatures above 700C and pressures up to 30 atmospheres. Membranes were synthesized by arc-rolling for metallic type membranes and incorporating Pd into a glass matrix for glass membranes. Testing for hydrogen permeability properties were completed and the effects of hydrogen sulfide and carbon monoxide were investigated for perspective membranes. The initial candidate membrane of Pd80Cu20 chosen in 2008 was selected for preliminary reactor design and cost estimates. Although the H2A analysis results indicated a $1.96 cost per gge H2 based on a 5A (micron) thick PdCu membrane, there was not long-term operation at the required flux to satisfy the go/no go decision. Since the future PSA case yielded a $2.00/gge H2, DOE decided that there was insufficient savings compared with the already proven PSA technology to further pursue the membrane reactor design. All ceramic membranes synthesized by ASU during the project showed low hydrogen flux as compared with metallic membranes. The best ceramic membrane showed hydrogen permeation flux of 0.03 SCFH/ft2 at the required process conditions while the metallic membrane, Pd80Cu20 showed a flux of 47.2 SCFH/ft2 (3 orders of magnitude difference). Results from

A rod-packing microporous hydrogen-bonded organic framework for highly selective separation of C2H2/CO2at room temperature

KAUST Repository

Li, Peng

2014-11-13

Self-assembly of a trigonal building subunit with diaminotriazines (DAT) functional groups leads to a unique rod-packing 3D microporous hydrogen-bonded organic framework (HOF-3). This material shows permanent porosity and demonstrates highly selective separation of C2H2/CO2 at ambient temperature and pressure.

A rod-packing microporous hydrogen-bonded organic framework for highly selective separation of C2H2/CO2at room temperature

KAUST Repository

Li, Peng; He, Yabing; Zhao, Yunfeng; Weng, Linhong; Wang, Hailong; Krishna, Rajamani A A; Wu, Hui; Zhou, Wei; O'Keeffe, Michael A.; Han, Yu; Chen, Banglin

2014-01-01

Self-assembly of a trigonal building subunit with diaminotriazines (DAT) functional groups leads to a unique rod-packing 3D microporous hydrogen-bonded organic framework (HOF-3). This material shows permanent porosity and demonstrates highly selective separation of C2H2/CO2 at ambient temperature and pressure.

Study of mechanism of hydrogen diffusion in separation devices. Progress report for 1980-1983

International Nuclear Information System (INIS)

Lee, M.H.

1983-01-01

For the purpose of studying the mechanisms of hydrogen diffusion in separation devices e.g. transition-metal membranes, we have developed a microscopic dynamic model appropriate for describing the nonequilibrium statistical mechanics of hydrogen-in-a-metal. Using this model we have carried out a detailed analysis to obtain the autocorrelation function of density fluctuations in the model. Our model is built on the physical idea that, at low temperatures, spin clusters are the basic units or aggregates of transport. Our work can explain the reversed isotope effect in diffusion. We have also obtained an expression for the relative diffusivity, verifiable by experiments with tritium in metals. Our notion of spin clusters is novel. There is some evidence of their existence. The interstitial spin clusters are comparable to atomic and nuclear spin clusters, the only other natural spin clusters. Our demonstration of a long-time tail in the autocorrelation function is also novel. Diffusion can be anomalous if long time tails exist, a current topic in nonlinear behavior of fluids and solids. Our progress has been made possible by our development in the mathematical method of solving the generalized Langevin equation. This method is applicable to any time-dependent quantum many-body model. The underlying basis of this method is our discovery of a new orthogonalization process in Hilbert space, first since Gram and Schmidt over 100 years ago. Our process is simpler if Hilbert space is realized as is for all physical problems. To demonstrate the power and utility of our method we considered a well established model of metals, thereby discovering the existence of a low-frequency electronic mobility. This kind of intrinsic conductivity should exist in ensembles of all light particles, hence also relevant to hydrogen and its isotopes in metals

Deposition of Pd–Ag thin film membranes on ceramic supports for hydrogen purification/separation

Energy Technology Data Exchange (ETDEWEB)

Pereira, A.I. [Centre of Physics, University of Minho, Campus Azurém, 4800-058 (Portugal); Pérez, P.; Rodrigues, S.C.; Mendes, A.; Madeira, L.M. [LEPAE, Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto (Portugal); Tavares, C.J., E-mail: ctavares@fisica.uminho.pt [Centre of Physics, University of Minho, Campus Azurém, 4800-058 (Portugal)

2015-01-15

Highlights: • Thin film Pd–Ag membranes have been produced for hydrogen selectivity. • Magnetron sputtering yields Pd–Ag compact films for atomic H diffusion. • The thin film Pd–Ag membranes yielded a selectivity of α (H{sub 2}/N{sub 2}) = 10. - Abstract: Pd–Ag based membranes supported on porous α-Al{sub 2}O{sub 3} (doped with yttria-stabilized zirconia) were studied for hydrogen selective separation. Magnetron sputtering technique was employed for the synthesis of thin film membranes. The hydrogen permeation flux is affected by the membrane columnar structure, which is formed during deposition. From scanning electron microscopy analysis, it was observed that different sputtering deposition pressures lead to distinct columnar structure growth. X-ray diffraction patterns provided evidence of a Pd–Ag solid solution with an average crystallite domain size of 21 nm, whose preferential growth can be altered by the deposition pressure. The gas-permeation results have shown that the Pd–Ag membrane supported on porous α-Al{sub 2}O{sub 3} is selective toward H{sub 2}. For optimized membrane synthesis conditions, the permeance toward N{sub 2} is 0.076 × 10{sup −6} mol m{sup −2} s{sup −1} Pa{sup −1} at room temperature, whereas for a pressure difference of 300 kPa the H{sub 2}-flux is of the order of ca. 0.21 mol m{sup −2} s{sup −1}, which corresponds to a permeance of 0.71 × 10{sup −6} mol m{sup −2} s{sup −1} Pa{sup −1}, yielding a selectivity of α (H{sub 2}/N{sub 2}) = 10. These findings suggest that the membrane has a reasonable capacity to selectively permeate this gas.

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

Thermal conductivity of Glycerol's liquid, glass, and crystal states, glass-liquid-glass transition, and crystallization at high pressures.

Science.gov (United States)

Andersson, Ove; Johari, G P

2016-02-14

To investigate the effects of local density fluctuations on phonon propagation in a hydrogen bonded structure, we studied the thermal conductivity κ of the crystal, liquid, and glassy states of pure glycerol as a function of the temperature, T, and the pressure, p. We find that the following: (i) κcrystal is 3.6-times the κliquid value at 140 K at 0.1 MPa and 2.2-times at 290 K, and it varies with T according to 138 × T(-0.95); (ii) the ratio κliquid (p)/κliquid (0.1 MPa) is 1.45 GPa(-1) at 280 K, which, unexpectedly, is about the same as κcrystal (p)/κcrystal (0.1 MPa) of 1.42 GPa(-1) at 298 K; (iii) κglass is relatively insensitive to T but sensitive to the applied p (1.38 GPa(-1) at 150 K); (iv) κglass-T plots show an enhanced, pressure-dependent peak-like feature, which is due to the glass to liquid transition on heating; (v) continuous heating cold-crystallizes ultraviscous glycerol under pressure, at a higher T when p is high; and (vi) glycerol formed by cooling at a high p and then measured at a low p has a significantly higher κ than the glass formed by cooling at a low p. On heating at a fixed low p, its κ decreases before its glass-liquid transition range at that p is reached. We attribute this effect to thermally assisted loss of the configurational and vibrational instabilities of a glass formed at high p and recovered at low p, which is different from the usual glass-aging effect. While the heat capacity, entropy, and volume of glycerol crystal are less than those for its glass and liquid, κcrystal of glycerol, like its elastic modulus and refractive index, is higher. We discuss these findings in terms of the role of fluctuations in local density and structure, and the relations between κ and the thermodynamic quantities.

Deconstructing three-dimensional (3D) structure of absorptive glass mat (AGM) separator to tailor pore dimensions and amplify electrolyte uptake

Science.gov (United States)

Rawal, Amit; Rao, P. V. Kameswara; Kumar, Vijay

2018-04-01

Absorptive glass mat (AGM) separator is a vital technical component in valve regulated lead acid (VRLA) batteries that can be tailored for a desired application. To selectively design and tailor the AGM separator, the intricate three-dimensional (3D) structure needs to be unraveled. Herein, a toolkit of 3D analytical models of pore size distribution and electrolyte uptake expressed via wicking characteristics of AGM separators under unconfined and confined states is presented. 3D data of fiber orientation distributions obtained previously through X-ray micro-computed tomography (microCT) analysis are used as key set of input parameters. The predictive ability of pore size distribution model is assessed through the commonly used experimental set-up that usually apply high level of compressive stresses. Further, the existing analytical model of wicking characteristics of AGM separators has been extended to account for 3D characteristics, and subsequently, compared with the experimental results. A good agreement between the theory and experiments pave the way to simulate the realistic charge-discharge modes of the battery by applying cyclic loading condition. A threshold criterion describing the invariant behavior of pore size and wicking characteristics in terms of maximum permissible limit of key structural parameters during charge-discharge mode of the battery has also been proposed.

A comparative study of ibuprofen and ketoprofen glass-forming liquids by molecular dynamics simulations

Science.gov (United States)

Ottou Abe, M. T.; Correia, N. T.; Ndjaka, J. M. B.; Affouard, F.

2015-10-01

In this paper, structural and dynamical properties of ibuprofen and ketoprofen glass-forming liquids have been investigated by means of molecular dynamics simulations. Molecular mobility of both materials is analyzed with respect to the different inter-molecular linear/cyclic hydrogen bonding associations. For ibuprofen, the dominant organization is found to be composed of small hydrogen bonding aggregates corresponding to cyclic dimers through the carboxyl group. For ketoprofen, the propensity of cyclic dimers is significantly reduced by the formation of hydrogen bonds with the ketone oxygen of the molecule altering the hydrogen bond (HB) associating structures that can be formed and thus molecular dynamics. The issue of the presence/absence of the peculiar low frequency Debye-type process in dielectric relaxation spectroscopy (DRS) data in these materials is addressed. Results obtained from simulations confirm that the Debye process originates from the internal cis-trans conversion of the —COOH carboxyl group. It is shown that the specific intermolecular HB structures associated to a given profen control the main dynamical features of this conversion, in particular its separation from the α-process, which make it detectable or not from DRS. For ibuprofen, the possible role of the —CCCO torsion motion, more "local" than the —COOH motion since it is less influenced by the intermolecular HBs, is suggested in the microscopic origin of the quite intense secondary γ-relaxation process detected from DRS.

Mars Atmospheric Capture and Gas Separation

Science.gov (United States)

Muscatello, Anthony; Santiago-Maldonado, Edgardo; Gibson, Tracy; Devor, Robert; Captain, James

2011-01-01

The Mars atmospheric capture and gas separation project is selecting, developing, and demonstrating techniques to capture and purify Martian atmospheric gases for their utilization for the production of hydrocarbons, oxygen, and water in ISRU systems. Trace gases will be required to be separated from Martian atmospheric gases to provide pure C02 to processing elements. In addition, other Martian gases, such as nitrogen and argon, occur in concentrations high enough to be useful as buffer gas and should be captured as welL To achieve these goals, highly efficient gas separation processes will be required. These gas separation techniques are also required across various areas within the ISRU project to support various consumable production processes. The development of innovative gas separation techniques will evaluate the current state-of-the-art for the gas separation required, with the objective to demonstrate and develop light-weight, low-power methods for gas separation. Gas separation requirements include, but are not limited to the selective separation of: (1) methane and water from un-reacted carbon oxides (C02- CO) and hydrogen typical of a Sabatier-type process, (2) carbon oxides and water from unreacted hydrogen from a Reverse Water-Gas Shift process, (3) carbon oxides from oxygen from a trash/waste processing reaction, and (4) helium from hydrogen or oxygen from a propellant scavenging process. Potential technologies for the separations include freezers, selective membranes, selective solvents, polymeric sorbents, zeolites, and new technologies. This paper and presentation will summarize the results of an extensive literature review and laboratory evaluations of candidate technologies for the capture and separation of C02 and other relevant gases.

On the nature of low temperature anomalies of metallic glass inelastic properties

International Nuclear Information System (INIS)

Spivak, L.V.; Khonik, V.A.

1997-01-01

Low-temperature (30 60 Nb 40 metallic glass (MG) exposed to the preliminary cold deformation via rolling, to high-temperature homogeneous deformation or to electrolytic hydrogen absorption were investigated. Conclusion is made that the published low-temperature peaks of the internal friction in quick-hardened cold-deformed or hydrogen absorbed MGs are of the common dislocation-like nature. Effect of 2 MeV electron irradiation on the temperature dependence of the internal friction and on the elasticity module of hydrogenated specimens was investigated, as well [ru

Superductile bulk metallic glass

International Nuclear Information System (INIS)

Yao, K.F.; Ruan, F.; Yang, Y.Q.; Chen, N.

2006-01-01

Usually, monolithic bulk metallic glasses undergo inhomogeneous plastic deformation and exhibit poor ductility (<2%) at room temperature. We report a newly developed Pd-Si binary bulk metallic glass, which exhibits a uniform plastic deformation and a large plastic engineering strain of 82% and a plastic true strain of 170%, together with initial strain hardening, slight strain softening and final strain hardening characteristics. The uniform shear deformation and the ultrahigh plasticity are mainly attributed to strain hardening, which results from the nanoscale inhomogeneity due to liquid phase separation. The formed nanoscale inhomogeneity will hinder, deflect, and bifurcate the propagation of shear bands

Canonical correlation of waste glass compositions and durability, including pH

International Nuclear Information System (INIS)

Oeksoy, D.; Pye, L.D.; Bickford, D.F.; Ramsey, W.G.

1993-01-01

Control of waste glass durability is a major concern in the immobilization of radioactive and mixed wastes. Leaching rate in standardized laboratory tests is being used as a demonstration of consistency of the response of waste glasses in the final disposal environment. The leaching of silicate and borosilicate glasses containing alkali or alkaline earth elements is known to be autocatalytic, in that the initial ion exchange of alkali in the glass for hydrogen ions in water results in the formation of OH and increases the pH of the leachate. The increased pH then increases the rate of silicate network attack, accelerating the leaching effect. In well formulated glasses this effect reaches a thermodynamic equilibrium when leachate saturation of a critical species, such as silica, or a dynamic equilibrium is reached when the pH shift caused by incremental leaching has negligible effect on pH. This report analyzes results of a seven leach test on waste glasses

Determination of hydrogen abundance in selected lunar soils

Science.gov (United States)

Bustin, Roberta

1987-01-01

Hydrogen was implanted in lunar soil through solar wind activity. In order to determine the feasibility of utilizing this solar wind hydrogen, it is necessary to know not only hydrogen abundances in bulk soils from a variety of locations but also the distribution of hydrogen within a given soil. Hydrogen distribution in bulk soils, grain size separates, mineral types, and core samples was investigated. Hydrogen was found in all samples studied. The amount varied considerably, depending on soil maturity, mineral types present, grain size distribution, and depth. Hydrogen implantation is definitely a surface phenomenon. However, as constructional particles are formed, previously exposed surfaces become embedded within particles, causing an enrichment of hydrogen in these species. In view of possibly extracting the hydrogen for use on the lunar surface, it is encouraging to know that hydrogen is present to a considerable depth and not only in the upper few millimeters. Based on these preliminary studies, extraction of solar wind hydrogen from lunar soil appears feasible, particulary if some kind of grain size separation is possible.

Study of powellite-rich glass-ceramics for nuclear waste immobilization

International Nuclear Information System (INIS)

Taurines, T.

2012-01-01

MoO 3 is poorly soluble in borosilicate glasses which can lead to the crystallization of undesired phases when its concentration or the charge load (minor actinides and fission products concentration) is too high. Crystallization control is needed to guarantee good immobilization properties. We studied powellite-rich glass-ceramics obtained from a simplified nuclear glass in the system SiO 2 - B 2 O 3 - Na 2 O - CaO - Al 2 O 3 - MoO 3 - RE 2 O 3 (RE = Gd, Eu, Nd) by various heat treatments. Rare earth elements (REE) were added as minor actinides surrogates and as spectroscopic probes. The influence of MoO 3 and RE 2 O 3 content on powellite (CaMoO 4 ) crystallization was investigated. Various glass-ceramics (similar residual glass + powellite) were obtained with large crystal size distributions. Phase separation due to molybdenum occurs during quenching when [MoO 3 ] ≥ 2.5 mol%. We showed that increasing the rare earth content can suppress the phase separation due to molybdenum but it leads to spinodal decomposition of the residual glass. Furthermore, we studied the effects of parent glass complexifying and the insertion of Gd 3+ ions into the powellite structure. In order to understand the influence of microstructure on evolutions under β-irradiation, we studied point defects creation and structural changes. We showed that the damage induced by electronic excitations in the glass-ceramics is driven by the damage in the residual glass. (author) [fr

Room temperature Sieving of Hydrogen Isotopes Using 2-D Materials

Energy Technology Data Exchange (ETDEWEB)

Hitchcock, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Colon-Mercado, H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Krentz, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Serkiz, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Velten, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Xiao, S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-09-28

Hydrogen isotope separation is critical to the DOE’s mission in environmental remediation and nuclear nonproliferation. Isotope separation is also a critical technology for the NNSA, and the ability to perform the separations at room temperature with a relatively small amount of power and space would be a major advancement for their respective missions. Recent work has shown that 2-D materials such as graphene and hexagonal boron nitride can act as an isotopic sieve at room temperature; efficiently separating hydrogen isotopes in water with reported separation ratios of 10:1 for hydrogen: deuterium separation for a single pass. The work performed here suggests that this technique has merit, and furthermore, we are investigating optimization and scale up of the required 2-D material based membranes.

Hydrogen and water reactor safety: proceedings

International Nuclear Information System (INIS)

1982-01-01

Separate abstracts were prepared for papers presented in the following areas of interest: 1) hydrogen research programs; 2) hydrogen behavior during light water reactor accidents; 3) combustible gas generation; 4) hydrogen transport and mixing; 5) combustion modeling and experiments; 6) accelerated flames and detonations; 7) combustion mitigation and control; and 8) equipment survivability

Hydrogen and water reactor safety: proceedings

Energy Technology Data Exchange (ETDEWEB)

1982-01-01

Separate abstracts were prepared for papers presented in the following areas of interest: 1) hydrogen research programs; 2) hydrogen behavior during light water reactor accidents; 3) combustible gas generation; 4) hydrogen transport and mixing; 5) combustion modeling and experiments; 6) accelerated flames and detonations; 7) combustion mitigation and control; and 8) equipment survivability.

On the nature of low temperature internal friction peaks in metallic glasses

International Nuclear Information System (INIS)

Khonik, V.A.; Spivak, L.V.

1996-01-01

Low temperature (30 60 Nb 40 subjected to preliminary inhomogeneous deformation by cold rolling, homogeneous tensile deformation or electrolytic charging with hydrogen is investigated. Cold rolling or hydrogenation result in appearance of similar internal friction peaks and hysteresis damping. Homogeneous deformation has no influence on low temperature internal friction. The phenomenon of microplastic deformation during hydrogenation of weakly stressed samples is revealed. It is argued that microplastic deformation of metallic glasses during hydrogenation without external stress takes place too. Plastic flow both on cold rolling and hydrogenation occurs via formation and motion of dislocation-like defects which are the reason of the observed anelastic anomalies. It is concluded that low temperature internal friction peaks described in the literature for as-cast, cold deformed and hydrogenated samples have common dislocation-like origin

UV-VUV laser induced phenomena in SiO2 glass

International Nuclear Information System (INIS)

Kajihara, Koichi; Ikuta, Yoshiaki; Oto, Masanori; Hirano, Masahiro; Skuja, Linards; Hosono, Hideo

2004-01-01

Creation and annihilation of point defects were studied for SiO 2 glass exposed to ultraviolet (UV) and vacuum UV (VUV) lights to improve transparency and radiation toughness of SiO 2 glass to UV-VUV laser light. Topologically disordered structure of SiO 2 glass featured by the distribution of Si-O-Si angle is a critical factor degrading transmittance near the fundamental absorption edge. Doping with terminal functional groups enhances the structural relaxation and reduces the number of strained Si-O-Si bonds by breaking up the glass network without creating the color centers. Transmittance and laser toughness of SiO 2 glass for F 2 laser is greatly improved in fluorine-doped SiO 2 glass, often referred as 'modified silica glass'. Interstitial hydrogenous species are mobile and reactive at ambient temperature, and play an important role in photochemical reactions induced by exposure to UV-VUV laser light. They terminate the dangling-bond type color centers, while enhancing the formation of the oxygen vacancies. These findings are utilized to develop a deep-UV optical fiber transmitting ArF laser photons with low radiation damage

Evidence for vitreous type orientational ordering in solid hydrogen and deuterium

International Nuclear Information System (INIS)

Devoret, M.

1982-09-01

This shown a new region in the concentration-temperature phase diagram for solid mixtures of ortho and para-hydrogen. This region is characterized by a vitreous type orientational, ordering, with the quadrupoles of the ortho molecules frozen in a random fashion. This new vitreous state is called a quadrupolar glass, with the degrees of freedom of quadrupolar moments frozen in solid hydrogen [fr

Mechanical properties of molybdenum-sealing glass-ceramics

International Nuclear Information System (INIS)

Swearengen, J.C.; Eagan, R.J.

1975-07-01

Elastic constants, thermal expansion, strength, and fracture toughness were determined for a molybdenum-sealing glass-ceramic containing approximately 31 volume percent Zn 2 SiO 4 crystals in a glass matrix. The microstructure was studied for two different crystallization treatments and moderate changes in composition. Mechanical properties of the composite were compared with the properties of the constituent phases through application of mixture theory and by fractographic observations. The reinforcing effects of the crystal phase at room temperature are evident in comparison with the properties of the residual glass but not necessarily in comparison with the parent glass. Fracture toughness of the composite depends primarily upon additive properties of the separate phases instead of by interactive effects such as microcracks. (U.S.)

Hydrogen study in melt inclusions trapped in quartz with nuclear microprobe

International Nuclear Information System (INIS)

Mosbah, M.; Tirira, J.; Gosset, J.; Massiot, P.

1990-01-01

Elastic recoil spectrometry induced by 3 MeV helium-4 microbeam has been used to determine hydrogen distribution within melt inclusions trapped in quartz. These minerals were selected from different geological environments: Guadeloupe (West Indies), Pantelleria Island (South Sicily - Italy) and San Pietro (South Sardinia - Italy). Bulk hydrogen contents are calculated (H assumed to be in H 2 O form). The knowledge of hydrogen distribution assists both in a better understanding and in the establishment of volcanic dynamism hypotheses. Finally, fluid hydrogen rich inclusions are evidenced and H concentration profile is simulated and reported for the first time in glass inclusion

Polymer Separators for High-Power, High-Efficiency Microbial Fuel Cells

KAUST Repository

Chen, Guang; Wei, Bin; Luo, Yong; Logan, Bruce E.; Hickner, Michael A.

2012-01-01

Microbial fuel cells (MFCs) with hydrophilic poly(vinyl alcohol) (PVA) separators showed higher Coulombic efficiencies (94%) and power densities (1220 mW m-2) than cells with porous glass fiber separators or reactors without a separator after 32

Deuterium isotope separation

International Nuclear Information System (INIS)

Benson, S.W.

1979-01-01

Deuterium-containing molecules are separated and enriched by exposing commercially available ethylene, vinyl chloride, 1,2-dichloroethane or propylene to the radiation of tuned infrared lasers to selectively decompose these compounds into enriched molecular products containing deuterium atoms. The deuterium containing molecules can be easily separated from the starting material by absorption, distillation or other simple chemical separation techniques and methods. After evaporation such deuterium containing molecules can be burned to form water with an enriched deuterium content or pyrolyzed to form hydrogen gas with an enriched deuterium content. (author)

Charge trapping and dielectric breakdown in lead silicate glasses

International Nuclear Information System (INIS)

Weeks, R.A.; Kinser, D.L.; Lee, J.M.

1976-01-01

When irradiated with beams of energetic electrons or gamma rays, many insulating glasses and plastics exhibit a spontaneous electrical discharge producing permanent patterns in the materials (Lichtenberg figures). In the case of inorganic glasses, this effect is not observed in pure silicate, germanate, or phosphate glasses nor in their crystalline forms and has only been reported in mixed-oxide glasses with low alkali content. In a series of lead silicate glasses of composition [PbO]/sub (x)/[SiO 2 ]/sub [1-(x)]/, the effect is observed only for 0 less than x less than or equal to 0.40. Changes in electrical properties are related to structural changes in these glasses. Electron microscopy of these glasses confirms the existence of microphase separation in the range 0.2 less than or equal to x less than or equal to 0.5

Characterization of leached surface layers on simulated high-level waste glasses by sputter-induced optical emission

International Nuclear Information System (INIS)

Houser, C.; Tsong, I.S.T.; White, W.B.

1979-01-01

The leaching process in simulated waste encapsulant glasses was studied by measuring the compositional depth-profiles of H (from water), the glass framework formers Si and B, the alkalis Na and Cs, the alkaline earths Ca and Sr, the transition metals Mo and Fe, the rare-earths La, Ce, and Nd, using the technique of sputter-induced optical emission. The leaching process of these glasses is highly complex. In addition to alkali/hydrogen exchange, there is breakdown of the glass framework, build-up of barrier layers on the surface, and formation of layered reaction zones of distinctly different chemistry all within the outer micrometer of the glass

Bench-Scale Study of Hydrogen Separation Using Pre-Commercial Membranes; Estudio, a Escala de Planta Piloto, del Proceso de Separacion de Hidrogeno mediante Membranas Pre-Comerciales

Energy Technology Data Exchange (ETDEWEB)

Sanchez Hervas, J. M.; Marano, M.

2011-11-10

This report compiles the research undertaken by CIEMAT over 2009-2011 in the sub-project 8 Purification and Separation of Hydrogen of the PSE H2ENOV Project funded by the Spanish Ministry of Science and Innovation, MICINN. Permeability and hydrogen selectivity of a pre-commercial palladium membrane was studied at bench scale level. The effect of main operating parameters - pressure, temperature and feed-flow-rate- on permeate flow-rate was determined. The influence of other gas components on hydrogen permeation was evaluated. Mixtures of H{sub 2}-N{sub 2} and H{sub 2}-CO{sub 2} were studied. Although nitrogen and carbon dioxide did not permeate, both components decreased hydrogen permeation rate. Operating the membrane for around 1000 h under various conditions showed a small decrease in hydrogen permeation, but not in selectivity. A literature review was done in order to identify causes for permeation inhibition and reduction and for the definition of procedures for membrane regeneration. (Author) 29 refs.

Electrical properties and flux performance of composite ceramic hydrogen separation membranes

DEFF Research Database (Denmark)

Fish, J.S.; Ricote, Sandrine; O'Hayre, R.

2015-01-01

The electrical properties and hydrogen permeation flux behavior of the all-ceramic protonic/electronic conductor composite BaCe0.2Zr0.7Y0.1O3-δ/Sr0.95Ti0.9Nb0.1O3-δ (BCZY27/STN95: BS27) are evaluated. Conductivity and hydrogen permeability are examined as a function of phase volume ratios. Total ...

Investigating the effect of V{sub 2}O{sub 5} addition on sodium barium borosilicate glasses

Energy Technology Data Exchange (ETDEWEB)

Halder, Rumu, E-mail: rumuhalder24feb@gmail.com; Sengupta, Pranesh; Dey, G. K. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai-700 085 (India); Sudarsan, V. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai-700 085 (India); Kaushik, C. P. [Waste Management Division, Bhabha Atomic Research Centre, Mumbai-700 085 (India)

2016-05-23

V{sub 2}O{sub 5} doped sodium barium borosilicate glasses were characterized by photoluminescence spectroscopy and electron probe microanalyzer (EPMA). The glass remains homogeneous for lower concentration of V{sub 2}O{sub 5} but a phase separation is observed when V{sub 2}O{sub 5} doping is increased beyond 5 mol%. Detailed microanalysis reveals that the phase separated glass consists of a phase containing V, Ba and Si and a separate Si rich phase within the glass matrix. The luminescence study demonstrated that at low concentration the vanadium mainly interacts with the structural units of B/Si while at higher concentrations, V-O-V/ V-O{sup −} Na{sup +}/Ba{sup 2+} linkages are formed.

Characterization of borosilicate glasses containing simulated high-level radioactive wastes from PNC

International Nuclear Information System (INIS)

Terai, R.; Eguchi, K.; Yamanaka, H.

1979-01-01

The characterization of borosilicate glasses containing simulated HLW from PNC has been carried out. Phase separation of molybdates, volatilization, viscosity, electrical resistivity, thermal conductivity, elastic modulus, chemical durability, and devitrification of these glasses have been measured, and the suitability of the glasses for the vitrified solidification processes is discussed from the viewpoint of safety

Statistical approach to study of lithium magnesium metaborate glasses

Directory of Open Access Journals (Sweden)

Nedyalkova Miroslava

2017-03-01

Full Text Available Alkali borate glasses and alkaline earth borate glasses are commonly used materials in the field of optoelectronics. Infrared (FTIR and Raman spectroscopy are valuable tools for structural investigation of borate glass networks. The compositional and structural variety of lithium magnesium metaborate glasses is usually determined by traditional instrumental methods. In this study a data set is classified by structural and physicochemical parameters (FTIR, Raman spectra, glass transition temperature-Tg. Characterisation of magnesium containing metaborate glasses by multivariate statistics (hierarchical cluster analysis to reveal potential relationships (similarity or dissimilarity between the type of glasses included in the data set using specific structural features available in the literature is conducted. The clustering of the glass objects indicates a good separation of different magnesium containing borate glass compositions. The grouping of variables concerning Tg and structural data for BO3 and BO4 linkage confirms that BO4/BO3 ratios strongly affect Tg. Additionally, patterns of similarity could be detected not only between the glass composition but also between the features (variables describing the glasses. The proposed approach can be further used as an expert tool for glass properties prediction or fingerprinting (identification of unknown compositions.

Gas separation using porous cement membrane.

Science.gov (United States)

Zhang, Weiqi; Gaggl, Maria; Gluth, Gregor J G; Behrendt, Frank

2014-01-01

Gas separation is a key issue in various industrial fields. Hydrogen has the potential for application in clean fuel technologies. Therefore, the separation and purification of hydrogen is an important research subject. CO2 capture and storage have important roles in "green chemistry". As an effective clean technology, gas separation using inorganic membranes has attracted much attention in the last several decades. Membrane processes have many applications in the field of gas separation. Cement is one type of inorganic material, with the advantages of a lower cost and a longer lifespan. An experimental setup has been created and improved to measure twenty different cement membranes. The purpose of this work was to investigate the influence of gas molecule properties on the material transport and to explore the influence of operating conditions and membrane composition on separation efficiency. The influences of the above parameters are determined, the best conditions and membrane type are found, it is shown that cementitious material has the ability to separate gas mixtures, and the gas transport mechanism is studied.

Standard test methods for determining chemical durability of nuclear, hazardous, and mixed waste glasses and multiphase glass ceramics: The product consistency test (PCT)

CERN Document Server

American Society for Testing and Materials. Philadelphia

2002-01-01

1.1 These product consistency test methods A and B evaluate the chemical durability of homogeneous glasses, phase separated glasses, devitrified glasses, glass ceramics, and/or multiphase glass ceramic waste forms hereafter collectively referred to as “glass waste forms” by measuring the concentrations of the chemical species released to a test solution. 1.1.1 Test Method A is a seven-day chemical durability test performed at 90 ± 2°C in a leachant of ASTM-Type I water. The test method is static and conducted in stainless steel vessels. Test Method A can specifically be used to evaluate whether the chemical durability and elemental release characteristics of nuclear, hazardous, and mixed glass waste forms have been consistently controlled during production. This test method is applicable to radioactive and simulated glass waste forms as defined above. 1.1.2 Test Method B is a durability test that allows testing at various test durations, test temperatures, mesh size, mass of sample, leachant volume, a...

Nonlinear Properties of Soft Glass Waveguides

DEFF Research Database (Denmark)

Steffensen, Henrik

-infrared applications and the THz applications. In the mid-infrared, it is investigated whether soft glasses are a suitable candidate for supercontinuum generation (SCG). A few commercially available fluoride fibers are tested for their zero dispersion wavelength (ZDW), a key property when determining the possibility......This thesis builds around the investigation into using soft glass materials for midinfrared and THz applications. Soft glasses is a term that cov ers a wide range of chemical compositions where many are yet to be fully investigated. The work in this thesis is separated in two parts, the mid...... of SCG in a fiber. A group of soft glasses, namely the chalcogenides, are known to display two photon absorption (TPA) which could potentially limit the SCG when this is initiated within the frequency range where this nonlinear process occur. An analytic model is presented to estimate the soliton self...

Compact PEM fuel cell system combined with all-in-one hydrogen generator using chemical hydride as a hydrogen source

International Nuclear Information System (INIS)

Kim, Jincheol; Kim, Taegyu

2015-01-01

Highlights: • Compact fuel cell system was developed for a portable power generator. • Novel concept using an all-in-one reactor for hydrogen generation was proposed. • Catalytic reactor, hydrogen chamber and separator were combined in a volume. • The system can be used to drive fuel cell-powered unmanned autonomous systems. - Abstract: Compact fuel cell system was developed for a portable power generator. The power generator features a polymer electrolyte membrane fuel cell (PEMFC) using a chemical hydride as a hydrogen source. The hydrogen generator extracted hydrogen using a catalytic hydrolysis from a sodium borohydride alkaline solution. A novel concept using an all-in-one reactor was proposed in which a catalyst, hydrogen chamber and byproduct separator were combined in a volume. In addition, the reactor as well as a pump, cooling fans, valves and controller was integrated in a single module. A 100 W PEMFC stack was connected with the hydrogen generator and was evaluated at various load conditions. It was verified that the stable hydrogen supply was achieved and the developed system can be used to drive fuel cell-powered unmanned autonomous systems.

Separation of FFA from Partially Hydrogenated Soybean Oil Hydrolysate by Means of Membrane Processing

DEFF Research Database (Denmark)

Jala, Ram Chandra Reddy; Guo, Zheng; Xu, Xuebing

2011-01-01

Different types of commercial porous and non-porous polymeric membranes have been investigated for their capabilities to separate free fatty acids (FFA) from hydrolysate of partially hydrogenated soybean oil. A regenerated cellulose (RC, PLAC) membrane exhibited the most prominent difference...... in rejection between FFA and glycerides and the highest flux (27 kg h−1 m−2) in hydrolysate ethanol solution. The results also showed that, besides the pore size of membrane, the membrane flux depended largely on the property matching between membrane and solvent, as observed (40 kg h−1 m−2) flux was achieved...... with methanol but no flux detected with hexane for PLAC. The polyvinyl alcohol (PVA, NTR-729 HF) and Polyamide (PA, NTR-759HR) membranes gave the second and third highest flux (10.1 and 5.7 kg h−1 m−2, respectively), where solute rejections for NTR-759HR were 95.9% for triacylglycerols (TG), 83...

Affinity separation based on hydrogen bonding

NARCIS (Netherlands)

Gruijters, B.W.T.

2007-01-01

The purification - work up and separation from other compounds - of chemical reactions is a crucial step in the synthesis of organic molecules. Therefore, organic chemists have developed a variety of work up and purification techniques throughout the last centuries, and novel methods are being

Hydrogen production by high-temperature gas-cooled reactor. Conceptual design of advanced process heat exchangers of the HTTR-IS hydrogen production system

International Nuclear Information System (INIS)

Sakaba, Nariaki; Ohashi, Hirofumi; Sato, Hiroyuki; Hara, Teruo; Kato, Ryoma; Kunitomi, Kazuhiko

2008-01-01

Nuclear hydrogen production is necessary in an anticipated hydrogen society that demands a massive quantity of hydrogen without economic disadvantage. Japan Atomic Energy Agency (JAEA) has launched the conceptual design study of a hydrogen production system with a near-term plan to connect it to Japan's first high-temperature gas-cooled reactor HTTR. The candidate hydrogen production system is based on the thermochemical water-splitting iodine sulphur (IS) process.The heat of 10 MWth at approximately 900degC, which can be provided by the secondary helium from the intermediate heat exchanger of the HTTR, is the energy input to the hydrogen production system. In this paper, we describe the recent progresses made in the conceptual design of advanced process heat exchangers of the HTTR-IS hydrogen production system. A new concept of sulphuric acid decomposer is proposed. This involves the integration of three separate functions of sulphuric acid decomposer, sulphur trioxide decomposer, and process heat exchanger. A new mixer-settler type of Bunsen reactor is also designed. This integrates three separate functions of Bunsen reactor, phase separator, and pump. The new concepts are expected to result in improved economics through construction and operation cost reductions because the number of process equipment and complicated connections between the equipment has been substantially reduced. (author)

Inexpensive driver for stereo videogame glasses

Science.gov (United States)

Pique, Michael; Coogan, Anthony

1990-09-01

We have adapted home videogame glasses from Sega as workstation stereo viewers. A small (4x7x9 cm.) box of electronics receives sync signals in parallel with the monitor (either separate ROB-Sync or composite video) and drives the glasses.The view is dimmer than with costlier shutters, there is more ghosting, and the user is feuered by the wires. But the glasses are so much cheaper than the full-screen shutters (250 instead of about 10 000) that it is practical to provide the benefits of stereo to many more workstation users. We are using them with Sun TAAC-1 workstations; the interlaced video can also be recorded on ordinary NTSC videotape and played on television monitors.

Liquid hydrogen in Japan

Energy Technology Data Exchange (ETDEWEB)

Yasumi, S. [Iwatani Corp., Osaka (Japan). Dept. of Overseas Business Development

2009-07-01

Japan's Iwatani Corporation has focused its attention on hydrogen as the ultimate energy source in future. Unlike the United States, hydrogen use and delivery in liquid form is extremely limited in the European Union and in Japan. Iwatani Corporation broke through industry stereotypes by creating and building Hydro Edge Co. Ltd., Japan's largest liquid hydrogen plant. It was established in 2006 as a joint venture between Iwatani and Kansai Electric Power Group in Osaka. Hydro Edge is Japan's first combined liquid hydrogen and ASU plant, and is fully operational. Liquid oxygen, liquid nitrogen and liquid argon are separated from air using the cryogenic energy of liquefied natural gas fuel that is used for power generation. Liquid hydrogen is produced efficiently and simultaneously using liquid nitrogen. Approximately 12 times as much hydrogen in liquid form can be transported and supplied as pressurized hydrogen gas. This technology is a significant step forward in the dissemination and expansion of hydrogen in a hydrogen-based economy.

Strong-Superstrong Transition in Glass Transition of Metallic Glass

International Nuclear Information System (INIS)

Dan, Wang; Hong-Yan, Peng; Xiao-Yu, Xu; Bao-Ling, Chen; Chun-Lei, Wu; Min-Hua, Sun

2010-01-01

Dynamic fragility of bulk metallic glass (BMG) of Zr 64 Cu 16 Ni 10 Al 10 alloy is studied by three-point beam bending methods. The fragility parameter mfor Zr 64 Cu 16 Ni 10 Al 10 BMG is calculated to be 24.5 at high temperature, which means that the liquid is a 'strong' liquid, while to be 13.4 at low temperature which means that the liquid is a 'super-strong' liquid. The dynamical behavior of Zr 64 Cu 16 Ni 10 Al 10 BMG in the supercooled region undergoes a strong to super-strong transition. To our knowledge, it is the first time that a strong-to-superstrong transition is found in the metallic glass. Using small angle x-ray scattering experiments, we find that this transition is assumed to be related to a phase separation process in supercooled liquid. (condensed matter: structure, mechanical and thermal properties)

Cheap non-toxic non-corrosive method of glass cleaning evaluated by contact angle, AFM, and SEM-EDX measurements.

Science.gov (United States)

Dey, Tania; Naughton, Daragh

2017-05-01

Glass surface cleaning is the very first step in advanced coating deposition and it also finds use in conserving museum objects. However, most of the wet chemical methods of glass cleaning use toxic and corrosive chemicals like concentrated sulfuric acid (H 2 SO 4 ), piranha (a mixture of concentrated sulfuric acid and 30% hydrogen peroxide), and hydrogen fluoride (HF). On the other hand, most of the dry cleaning techniques like UV-ozone, plasma, and laser treatment require costly instruments. In this report, five eco-friendly wet chemical methods of glass cleaning were evaluated in terms of contact angle (measured by optical tensiometer), nano-scale surface roughness (measured by atomic force microscopy or AFM), and elemental composition (measured by energy dispersive x-ray spectroscopy or SEM-EDX). These glass cleaning methods are devoid of harsh chemicals and costly equipment, hence can be applied in situ in close proximity with plantation such as greenhouse or upon subtle objects such as museum artifacts. Out of these five methods, three methods are based on the chemical principle of chelation. It was found that the citric acid cleaning method gave the greatest change in contact angle within the hydrophilic regime (14.25° for new glass) indicating effective cleansing and the least surface roughness (0.178 nm for new glass) indicating no corrosive effect. One of the glass sample showed unique features which were traced backed to the history of the glass usage.

Influence of hydrogen absorption on magnetic ordering in some zirconium-based Laves phase compounds

International Nuclear Information System (INIS)

Fujii, H.; Pourarian, F.; Wallace, W.E.

1982-01-01

Magnetization measurements were carried out on several zirconium-based hexagonal Laves phase compounds, i.e. the ZrMnsub(2+delta), (Zr,Ti)Mn 2 , Zr(Mn,Fe) 2 and Zr(Fe,Al) 2 systems and their hydrides. The absorbed hydrogen leads to a large increase (20%-30%) in volume without a change in the crystal structure. ZrMnsub(2+delta) is a weak Pauli paramagnet but becomes a spin glass near-ferromagnet by hydriding, indicating that the manganese moments are subjected to competing ferromagnetic and antiferromagnetic coupling tendencies. In the (Zrsub(1-x)Tisub(x))Mn 2 hydrides, ferromagnetic, spin-glass-like, ferromagnetic and antiferromagnetic behaviors appear at 4.2 K in the sequence of increasing x and/or decrease in hydrogen concentration. In the Zr(Mn,Fe) 2 system, the hydrogen absorption increases both the magnetic moments and the magnetic transition temperatures, while absorbed hydrogen leads to suppression of ferromagnetism in the Zr(Fe,Al) 2 system. These varied and complex magnetic behaviors are attributed to the effects of (1) variations in the interatomic distances, (2) changes in the 3d electron concentration and (3) varying local hydrogen concentrations occurring as a result of statistical fluctuations. (Auth.)

Enhancement of thermal neutron shielding of cement mortar by using borosilicate glass powder.

Science.gov (United States)

Jang, Bo-Kil; Lee, Jun-Cheol; Kim, Ji-Hyun; Chung, Chul-Woo

2017-05-01

Concrete has been used as a traditional biological shielding material. High hydrogen content in concrete also effectively attenuates high-energy fast neutrons. However, concrete does not have strong protection against thermal neutrons because of the lack of boron compound. In this research, boron was added in the form of borosilicate glass powder to increase the neutron shielding property of cement mortar. Borosilicate glass powder was chosen in order to have beneficial pozzolanic activity and to avoid deleterious expansion caused by an alkali-silica reaction. According to the experimental results, borosilicate glass powder with an average particle size of 13µm showed pozzolanic activity. The replacement of borosilicate glass powder with cement caused a slight increase in the 28-day compressive strength. However, the incorporation of borosilicate glass powder resulted in higher thermal neutron shielding capability. Thus, borosilicate glass powder can be used as a good mineral additive for various radiation shielding purposes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structural stability of Pd40Cu30Ni10P20 metallic glass in supercooled liquid region

International Nuclear Information System (INIS)

Jiang, J.Z.; Saksl, K.

2004-01-01

Phase separation of bulk and ribbon Pd 40 Cu 30 Ni 10 P 20 glasses, annealed in the supercooled liquid region at ambient pressure and high pressures, has been studied by means of differential scanning calorimetry (DSC) and X-ray diffraction techniques. DSC measurements show only one glass transition event in all annealed samples, indicating that no phase separation occurs in the alloy annealed in the supercooled liquid region. Phase analyses reveal at least six crystalline phases in the crystallized sample: monoclinic, tetragonal Cu 3 Pd-like, rhombohedral, fcc-Ni 2 Pd 2 P, fcc-(Ni, Pd) solid solution, and body-centered tetragonal (bct) Ni 3 P-like phases. Annealing treatments under external pressures in the vicinity of the glass transition temperature neither induce phase separation nor alter the glass transition temperature of the Pd 40 Cu 30 Ni 10 P 20 bulk glass

Enhanced Hydrogen Production Integrated with CO2 Separation in a Single-Stage Reactor

Energy Technology Data Exchange (ETDEWEB)

Shwetha Ramkumar; Mahesh Iyer; Danny Wong; Himanshu Gupta; Bartev Sakadjian; Liang-Lhih Fan

2008-09-30

High purity hydrogen is commercially produced from syngas by the Water Gas Shift Reaction (WGSR) in high and low temperature shift reactors using iron oxide and copper catalysts respectively. However, the WGSR is thermodynamically limited at high temperatures towards hydrogen production necessitating excess steam addition and catalytic operation. In the calcium looping process, the equilibrium limited WGSR is driven forward by the incessant removal of CO{sub 2} by-product through the carbonation of calcium oxide. At high pressures, this process obviates the need for a catalyst and excess steam requirement, thereby removing the costs related to the procurement and deactivation of the catalyst and steam generation. Thermodynamic analysis for the combined WGS and carbonation reaction was conducted. The combined WGS and carbonation reaction was investigated at varying pressures, temperatures and S/C ratios using a bench scale reactor system. It was found that the purity of hydrogen increases with the increase in pressure and at a pressure of 300 psig, almost 100% hydrogen is produced. It was also found that at high pressures, high purity hydrogen can be produced using stoichiometric quantities of steam. On comparing the catalytic and non catalytic modes of operation in the presence of calcium oxide, it was found that there was no difference in the purity of hydrogen produced at elevated pressures. Multicyclic reaction and regeneration experiments were also conducted and it was found that the purity of hydrogen remains almost constant after a few cycles.

Acidity Measurements with the Glass Electrode in H2O-D2O Mixtures

DEFF Research Database (Denmark)

Mikkelsen, K.; Nielsen, Sigurd Olaf

1960-01-01

Determinations at 22° of the thermodynamic dissociation constant of acetic arid in ordinary water and in deuteriumenriched water (98.0 volume % D20) demonstrate that an ordinary Radiometer glass electrode type G 202A under convenient experimental conditions exhibits the theoretical response...... to variations in the hydrogen-ion concentration in both solvents in the range between 2 x 10 -2 and 2 x 10 -5 M. The acidity determinations involve standardization and storage of the glass electrode in solutions in HzO and subsequent drying of the glass electrode with mercury before immersing it in the 0.5-ml...

CHROMATOGRAPHIC SEPARATION AND SPECTRO ...

African Journals Online (AJOL)

Four different fractions having colours yellow, grey, orange and ... Two different dyes vis a vis: methylene blue and malachite green dyes have been separated .... hydrogen carbonate of alkaline and alkaline earth metals in the samples.

Gas-Liquid Separator design of SWRPRS in PGSFR

Energy Technology Data Exchange (ETDEWEB)

Yoon, Jung; Lee, Tae-ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

There is the Sodium-Water Reaction Pressure Relief System (SWRPRS) in PGSFR to prevent the Sodium- Water Reaction (SWR) due to the break of the steam generator tube. The piping to atmosphere includes several components such as gasliquid separator, backpressure rupture disk, and hydrogen igniter. Among these components, gas-liquid separator separates the liquid sodium which is included in gas SWR products not to react sodium and air. In this study, the size of gas-liquid separator, which is based on the hydrogen volume which is exhausted in the sodium dump tank, is determined. To determine the gas-liquid separator for the separation of gas and sodium particle dumped the SDT, Stairmand's model which has high performance among standard cyclone separator models is selected. The body diameter is determined, and other dimensions are determined due to the ratio about the body diameter. Shepherd and Lapple's model is selected as the pressure drop calculation model considering the conservation.

Texaco, carbide form hydrogen plant venture

International Nuclear Information System (INIS)

Anon.

1992-01-01

This paper reports that Texaco Inc. and Union Carbide Industrial Gases Inc. (UCIG) have formed a joint venture to develop and operate hydrogen plants. The venture, named HydroGEN Supply Co., is owned by Texaco Hydrogen Inc., a wholly owned subsidiary of Texaco, and UCIG Hydrogen Services Inc., a wholly owned subsidiary of UCIG. Plants built by HydroGEN will combine Texaco's HyTEX technology for hydrogen production with UCIG's position in cryogenic and advanced air separation technology. Texaco the U.S. demand for hydrogen is expected to increase sharply during the next decade, while refinery hydrogen supply is expected to drop. The Clean Air Act amendments of 1990 require U.S. refiners to lower aromatics in gasoline, resulting in less hydrogen recovered by refiners from catalytic reforming units. Meanwhile, requirements to reduce sulfur in diesel fuel will require more hydrogen capacity

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)

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

Predicting glass-to-glass and liquid-to-liquid phase transitions in supercooled water using classical nucleation theory

Science.gov (United States)

Tournier, Robert F.

2018-01-01

Glass-to-glass and liquid-to-liquid phase transitions are observed in bulk and confined water, with or without applied pressure. They result from the competition of two liquid phases separated by an enthalpy difference depending on temperature. The classical nucleation equation of these phases is completed by this quantity existing at all temperatures, a pressure contribution, and an enthalpy excess. This equation leads to two homogeneous nucleation temperatures in each liquid phase; the first one (Tn- below Tm) being the formation temperature of an "ordered" liquid phase and the second one corresponding to the overheating temperature (Tn+ above Tm). Thermodynamic properties, double glass transition temperatures, sharp enthalpy and volume changes are predicted in agreement with experimental results. The first-order transition line at TLL = 0.833 × Tm between fragile and strong liquids joins two critical points. Glass phase above Tg becomes "ordered" liquid phase disappearing at TLL at low pressure and at Tn+ = 1.302 × Tm at high pressure.

Separation of pure Cerium oxides from rare earth compounds. Homogeneous precipitation using Urea-Hydrogen Peroxide

International Nuclear Information System (INIS)

Umeda, K.; Abrao, E.

1975-01-01

The obtainment of ceric oxide (CeO 2 ) of purity higher than 97% by application of homogeneous precipitation technique is described. The selective separation of cerium was reached by hydrolysis of urea in the presence of hydrogen peroxide, using a rare earths concentrate named rare earths chloride, a natural mixture of all lanthanides provenient from the industrialization of monazite. The best conditions for the preparation of CeO 2 of 94% purity are: 35-70g R 2 O 3 /1 and pH2,0 hydrolysis temperature: 88-90 0 C, urea/R 2 O 3 ratio: 4, H 2 O 2 /Ce 2 O 3 ratio: 1,5-5,0 and hydrolysis duration: 4 hours. A leaching procedure of the precipitate with 0,25-0,75M NHO 3 leads to a product of 97-99,5% CeO 2

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.

Electrical conductivity and viscosity of borosilicate glasses and melts

DEFF Research Database (Denmark)

Ehrt, Doris; Keding, Ralf

2009-01-01

, 0 to 62·5 mol% B2O3, and 25 to 85 mol% SiO2. The glass samples were characterised by different methods. Refractive indices, density and thermal expansion were measured. Phase separation effects were investigated by electron microscopy. The electrical conductivity of glasses and melts were determined......Simple sodium borosilicate and silicate glasses were melted on a very large scale (35 l Pt crucible) to prepare model glasses of optical quality in order to investigate various properties depending on their structure. The composition of the glass samples varied in a wide range: 3 to 33·3 mol% Na2O...... by impedance measurements in a wide temperature range (250 to 1450°C). The activation energies were calculated by Arrhenius plots in various temperature regions: below the glass transition temperature, Tg, above the melting point, Tl, and between Tg and Tl. Viscosity measurements were carried out...

Composition and property measurements for PHA Phase 4 glasses

International Nuclear Information System (INIS)

Edwards, T.B.

2000-01-01

The results presented in this report are for nine Precipitate Hydrolysis Aqueous (PHA) Phase 4 glasses. Three of the glasses contained HM sludge at 22, 26, and 30 wt% respectively, 10 wt% PHA and 1.25 wt% monosodium titanate (MST), all on an oxide basis. The remaining six glasses were selected from the Phase 1 and Phase 2 studies (Purex sludge) but with an increased amount of MST. The high-end target for MST of 2.5 wt% oxide was missed in Phases 1 and 2 due to ∼30 wt% water content of the MST. A goal of this Phase 4 study was to determine whether this increase in titanium concentration from the MST had any impact on glass quality or processibility. Two of the glasses, pha14c and pha15c, were rebatched and melted due to apparent batching errors with pha14 and pha15. The models currently in the Defense Waste Processing Facility's (DWPF) Product Composition Control System (PCCS) were used to predict durability, homogeneity, liquidus, and viscosity for these nine glasses. All of the HM glasses and half of the Purex glasses were predicted to be phase separated, and consequently prediction of glass durability is precluded with the cument models for those glasses that failed the homogeneity constraint. If one may ignore the homogeneity constraint, the measured durabilities were within the 95% prediction limits of the model. Further efforts will be required to resolve this issue on phase separation (inhomogeneity). The liquidus model predicted unacceptable liquidus temperatures for four of the nine glasses. The approximate, bounding liquidus temperatures measured for all had upper limits of 1,000 C or less. Given the fact that liquidus temperatures were only approximated, the 30 wt% loading of Purex may be near or at the edge of acceptability for liquidus. The measured viscosities were close to the predictions of the model. For the Purex glasses, pha12c and pha15c, the measured viscosities of 28 and 23 poise, respectively, indicate that DWPF processing may be compromised

Nickel-hydrogen battery with oxygen and electrolyte management features

Science.gov (United States)

Sindorf, John F.

1991-10-22

A nickel-hydrogen battery or cell having one or more pressure vessels containing hydrogen gas and a plurality of cell-modules therein. Each cell-module includes a configuration of cooperatively associated oxygen and electrolyte mangement and component alignment features. A cell-module having electrolyte includes a negative electrode, a positive electrode adapted to facilitate oxygen diffusion, a separator disposed between the positive and negative electrodes for separating them and holding electrolyte for ionic conductivity, an absorber engaging the surface of the positive electrode facing away from the separator for providing electrolyte to the positive electrode, and a pair of surface-channeled diffusion screens for enclosing the positive and negative electrodes, absorber, and separator and for maintaining proper alignment of these components. The screens, formed in the shape of a pocket by intermittently sealing the edges together along as many as three sides, permit hydrogen gas to diffuse therethrough to the negative electrodes, and prevent the edges of the separator from swelling. Electrolyte is contained in the cell-module, absorbhed by the electrodes, the separator and the absorber.

Glovebox atmosphere detritiation process using gas separation membranes

International Nuclear Information System (INIS)

Le Digabel, M.; Truan, P.A.; Ducret, D.; Laquerbe, C.; Perriat, P.; Niepce, J.C.; Pelletier, T.

2003-01-01

The use of gas separation membranes in atmospheric detritiation systems has been studied. The main advantage of this new process is to reduce the number and/or the size of the equipment in comparison to conventional tritium removal systems. Owing to the constraints linked to tritium handling, the separation performances of several commercial hollow fiber organic membranes have been analyzed, under various operating conditions, with hydrogen/nitrogen or deuterium/nitrogen mixtures. The experiments are performed with small quantities of hydrogen or deuterium (5000 ppm). The experimental results allow to evaluate the separation efficiency of these membranes and to determine the appropriate operating conditions to apply to a membrane detritiation process

Glass viscosity calculation based on a global statistical modelling approach

Energy Technology Data Exchange (ETDEWEB)

Fluegel, Alex

2007-02-01

A global statistical glass viscosity model was developed for predicting the complete viscosity curve, based on more than 2200 composition-property data of silicate glasses from the scientific literature, including soda-lime-silica container and float glasses, TV panel glasses, borosilicate fiber wool and E type glasses, low expansion borosilicate glasses, glasses for nuclear waste vitrification, lead crystal glasses, binary alkali silicates, and various further compositions from over half a century. It is shown that within a measurement series from a specific laboratory the reported viscosity values are often over-estimated at higher temperatures due to alkali and boron oxide evaporation during the measurement and glass preparation, including data by Lakatos et al. (1972) and the recently published High temperature glass melt property database for process modeling by Seward et al. (2005). Similarly, in the glass transition range many experimental data of borosilicate glasses are reported too high due to phase separation effects. The developed global model corrects those errors. The model standard error was 9-17°C, with R^2 = 0.985-0.989. The prediction 95% confidence interval for glass in mass production largely depends on the glass composition of interest, the composition uncertainty, and the viscosity level. New insights in the mixed-alkali effect are provided.

Development of Automotive Liquid Hydrogen Storage Systems

Science.gov (United States)

Krainz, G.; Bartlok, G.; Bodner, P.; Casapicola, P.; Doeller, Ch.; Hofmeister, F.; Neubacher, E.; Zieger, A.

2004-06-01

Liquid hydrogen (LH2) takes up less storage volume than gas but requires cryogenic vessels. State-of-the-art applications for passenger vehicles consist of double-wall cylindrical tanks that hold a hydrogen storage mass of up to 10 kg. The preferred shell material of the tanks is stainless steel, since it is very resistant against hydrogen brittleness and shows negligible hydrogen permeation. Therefore, the weight of the whole tank system including valves and heat exchanger is more than 100 kg. The space between the inner and outer vessel is mainly used for thermal super-insulation purposes. Several layers of insulation foils and high vacuums of 10-3 Pa reduce the heat entry. The support structures, which keep the inner tank in position to the outer tank, are made of materials with low thermal conductivity, e.g. glass or carbon fiber reinforced plastics. The remaining heat in-leak leads to a boil-off rate of 1 to 3 percent per day. Active cooling systems to increase the stand-by time before evaporation losses occur are being studied. Currently, the production of several liquid hydrogen tanks that fulfill the draft of regulations of the European Integrated Hydrogen Project (EIHP) is being prepared. New concepts of lightweight liquid hydrogen storage tanks will be investigated.

Chromatographic enrichment of isotopes in hydrogen and water samples on palladium

International Nuclear Information System (INIS)

Andreev, B.M.; Polevoi, A.S.; Perevezentsev, A.N.

1987-01-01

Data on the isotopic enrichment of hydrogen and water samples by chromatography on palladium have been analyzed. Experimental data on the effect of temperature, hydrogen flow, volume of the enriched fraction, and length of the chromatographic column on the degree of separation attainable in the column have been obtained. It has been shown that the maximum separation achievable (regardless of the type of the isotope mixture) at 273 K falls with increase of hydrogen flow and volume of the enriched gas fraction recoverable from the column. A separation degree of ∼ 1040 has been achieved for a mixture of protium and deuterium in a 10-mm wide and 0.6-m long chromatographic column packed with palladium black with a grain size of 0.2-0.5 mm at 273 K and a specific hydrogen flow of 1.22 mole/m 2 x sec. For a protium-tritium mixture a separation degree of ∼ 90 has been reached in a similar column at 273 K and a specific hydrogen flow of 0.4 mole/m 2 x sec

Gas separation by pressure swing adsorption

International Nuclear Information System (INIS)

Martin, J.R.; Gottzman, C.F.; Notaro, F.; Stewart, H.A.

1986-01-01

Over the past twenty years separation processes based upon pressure swing adsorption have replaced cryogenic processes in a number of selected applications such as air separation for production of moderate quantities of nitrogen and oxygen and recovery of hydrogen from refinery and chemical plant gases. Key events contributing to the emergence of PSA as an important process option have been the development of synthetic zeolite molecular sieves by Union Carbide Corporation in the USA and of carbon molecular sieves by Bergbau-Forschung in Germany. Today PSA processes enjoy significant commercial use producing oxygen from 0.1 Nm 3 /h for medical application to 1500 Nm 3 /h for steel mill use, for making nitrogen up to 1000 Nm 3 /h for inerting and in purifying hydrogen streams of up to 100,000 Nm 3 /h for refinery use. In this paper some of the principles of adsorptive separations are reviewed. The history of the technology is traced briefly with emphasis on key material, process and application events. The major commercial processes in the application of adsorption to bulk separation of air and hydrogen purification are reviewed in more detail with comparisons made to cryogenic alternatives in terms of specific characteristics, advantages and disadvantages where appropriate. Information on performance, reliability and comparative economics are discussed where available

Biological wastewater treatment technology with application of multihole glasses. Takoshitsu glass wo riyoshita biseibutsu ni yoru haisui shoriho no kenkyu

Energy Technology Data Exchange (ETDEWEB)

Honda, S; Murayama, Y; Tanaka, H; Yazawa, T; Eguchi, K [Government Industrial Research Institute, Osaka (Japan)

1991-11-25

This paper describes efficiency improvement in wastewater treatment to separate SS component using anaerobic fermentation with fixable microorganisms and multihole glass separation films. Measurement of microorganism deposition on microporous PVF resin in a fermentation tank revealed that hydrophilic resins with smooth surface have better deposition, and the suitable carrier hole diameters were from 300[mu]m to 500[mu]m. Adding slightly-soluble carbonate when bacteria are fixed collectively is effective in preserving the entire methane fermentation reaction system and stabilizing the carriers. A composite film comprising SiO2-ZrO2-based porous glass made by using a sol-gel process and porous ceramics had the maximum desalination rate reaching 90%. The permeation rate at a film thickness of 2[mu]m was 46 times as much of that for 500-[mu]m single-layer porous glass. As a result of reforming the pore surface by introducing -Si(CH3)3, the film has turned affinitive to non-polar solvent, repelling water to permeate. In an experiment for fermentation liquid permeation of separation film composite bioreactor using digestive sludge, the higher the SS particle concentration, the more the initial clogging was difficult to occur. The film permeating flow velocity showed a maximum value at hole diameters of about 0.2[mu]m. 3 refs., 6 figs., 2 tabs.

Liquid hydrogen production via hydrogen sulfide methane reformation

Science.gov (United States)

Huang, Cunping; T-Raissi, Ali

Hydrogen sulfide (H 2S) methane (CH 4) reformation (H 2SMR) (2H 2S + CH 4 = CS 2 + 4H 2) is a potentially viable process for the removal of H 2S from sour natural gas resources or other methane containing gases. Unlike steam methane reformation that generates carbon dioxide as a by-product, H 2SMR produces carbon disulfide (CS 2), a liquid under ambient temperature and pressure-a commodity chemical that is also a feedstock for the synthesis of sulfuric acid. Pinch point analyses for H 2SMR were conducted to determine the reaction conditions necessary for no carbon lay down to occur. Calculations showed that to prevent solid carbon formation, low inlet CH 4 to H 2S ratios are needed. In this paper, we analyze H 2SMR with either a cryogenic process or a membrane separation operation for production of either liquid or gaseous hydrogen. Of the three H 2SMR hydrogen production flowsheets analyzed, direct liquid hydrogen generation has higher first and second law efficiencies of exceeding 80% and 50%, respectively.

Applicability test of glass lining material for high-temperature acidic solutions of sulfuric acid in thermochemical water-splitting IS process

International Nuclear Information System (INIS)

Iwatsuki, Jin; Tanaka, Nobuyuki; Terada, Atsuhiko; Onuki, Kaoru; Watanabe, Yutaka

2010-01-01

A key issue for realizing the thermochemical IS process for hydrogen production is the selection of materials for working with high-temperature acidic solutions of sulfuric acid and hydriodic acid. Glass lining material is a promising candidate, which is composed of steel having good strength and glass having good corrosion resistance. Since the applicability of glass lining material depends strongly on the service condition, corrosion tests using glass used in glass lining material and heat cycle tests using glass lining piping were carried out to examine the possibility of using the glass lining material with high-temperature acidic solutions of sulfuric acid. It was confirmed that the glass lining materials exhibited sufficient corrosion resistance and heat resistance in high-temperature sulfuric acid of the IS process. (author)

Method of deuterium isotope separation and enrichment

International Nuclear Information System (INIS)

Benson, S.W.

1978-01-01

A method of separating deuterium, i.e., heavy hydrogen, from certain naturally occurring sources using tuned infrared lasers to selectively decompose specified classes of organic molecules (i.e., RX) into enriched molecular products containing deuterium atoms is described. The deuterium containing molecules are easily separated from the starting material by absorption, distillation or other simple chemical separation techniques and methods. After evaporation such deuterium containing molecules can be burned to form water with an enriched deuterium content or pyrolyzed to form hydrogen gas with an enriched deuterium content. The undecomposed molecules and the other reaction products which are depleted of their deuterium containing species can be catalytically treated, preferably using normal water, to restore the natural abundance of deuterium and such restored molecules can then be recycled

Distribution of implanted hydrogen in amorphous silicon dioxide a-SiO2

International Nuclear Information System (INIS)

Mokrushin, A.D.; Agafonov, Yu.A.; Zinenko, V.I.; Pustovit, A.N.

2004-01-01

Hydrogen SIMS distributions are measured in quartz glasses implanted by different doses of H 2 + ions with energy 40 keV. There are two features in distributions: the availability of intensive peak close to the surface and near-constant dependence at large depth up to ions range. These peculiarities are perhaps attributable to the radiation induced diffusion of hydrogen atoms back to the surface via which ions are implanted [ru

Formulation and synthesis by melting process of titanate enriched glass-ceramics and ceramics

International Nuclear Information System (INIS)

Advocat, T.; Fillet, C.; Lacombe, J.; Bonnetier, A.; McGlinn, P.

1999-01-01

The main objective of this work is to provide containment for the separated radionuclides in stable oxide phases with proven resistance to leaching and irradiation damage and in consequence to obtain a glass ceramic or a ceramic material using a vitrification process. Sphene glass ceramic, zirconolite glass ceramic and zirconolite enriched ceramic have been fabricated and characterized by XRD, SEM/EDX and DTA

Recycle Glass in Foam Glass Production

DEFF Research Database (Denmark)

Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

The foam glass industry turn recycle glass into heat insulating building materials. The foaming process is relative insensitive to impurities in the recycle glass. It is therefore considered to play an important role in future glass recycling. We show and discuss trends of use of recycled glasses...... in foam glass industry and the supply sources and capacity of recycle glass....

Phase transformations in lithium bearing sodiumborosilicate base glass melts for the solidification of HAW

International Nuclear Information System (INIS)

Goettlicher, J.

1994-10-01

Metastable phase separation has been observed in the Li-bearing basic glass SM58. This observation gave rise to examine the exsolution behaviour in model glasses by chemical substitution. It is impossible to produce metastable phase separation in the Li-free HAW-glasses VG98/12 and VG98/12.2. However, one can't exclude textural changes of Li-bearing glasses, because in a HAW-container the central temperature remains at about 300 C for more than 50 years. For the first time it has been tried to find a relationship between glass textures and structural parameters by combining textural investigations (electron microscopy) with structural determinations (NMR, WAXS). Modell glasses belong to the system (Li, Na) 2 O.B 2 O 3 , (Al 2 O 3 ).n(TO 2 ), with T=Si, Ge and n=2, 4, 6. Furthermore glasses from the KfK and from Mol (PAMELA) were investigated. A newly built apparatus was used to prepare glasses by replica technique (PtIrC oblique shadowing) for TEM investigations. This method turned out to be well suited to study glass textures with features down to 5 nm. Sometimes direct examinations of ion-thinned glasses showed that their textures were affected by radiation damage, caused by accelerated electrons. LVSE-(Low Voltage Scanning Electron)- and AF-(Atomic Force)- microscopy seems to be a promising method for studying glass surfaces and their textures directly. (orig./MM) [de

Analyses to support development of risk-informed separation distances for hydrogen codes and standards.

Energy Technology Data Exchange (ETDEWEB)

LaChance, Jeffrey L.; Houf, William G. (Sandia National Laboratories, Livermore, CA); Fluer, Inc., Paso Robels, CA; Fluer, Larry (Fluer, Inc., Paso Robels, CA); Middleton, Bobby

2009-03-01

The development of a set of safety codes and standards for hydrogen facilities is necessary to ensure they are designed and operated safely. To help ensure that a hydrogen facility meets an acceptable level of risk, code and standard development organizations are tilizing risk-informed concepts in developing hydrogen codes and standards.

Stable catalyst layers for hydrogen permeable composite membranes

Science.gov (United States)

Way, J. Douglas; Wolden, Colin A

2014-01-07

The present invention provides a hydrogen separation membrane based on nanoporous, composite metal carbide or metal sulfide coated membranes capable of high flux and permselectivity for hydrogen without platinum group metals. The present invention is capable of being operated over a broad temperature range, including at elevated temperatures, while maintaining hydrogen selectivity.

Investigations of glass structure using fluorescence line narrowing and moleuclar dynamics simulations

International Nuclear Information System (INIS)

Weber, M.J.; Brawer, S.A.

1982-01-01

The local structure at individual ion sites in simple and multicomponent glasses is simulated using methods of molecular dynamics. Computer simulations of fluoroberyllate glasses predict a range of ion separations and coordination numbers that increases with increasing complexity of the glass composition. This occurs at both glass forming and glass modifying cation sites. Laser-induced fluorescence line-narrowing techniques provide a unique probe of the local environments of selected subsets of ions and are used to measure site to site variations in the electronic energy levels and transition probabilities of rare earth ions. These and additional results from EXAFS, neutron and x-ray diffraction, and NMR experiments are compared with simulated glass structures

Crystallization in Y-Si-Al-O-N glasses

Energy Technology Data Exchange (ETDEWEB)

Leng-Ward, G; Lewis, M H

1985-05-01

The development of crystallization in oxynitride glasses has been characterized using transmission electron microscopy and scanning electron microscopy, X-ray (energy-dispersive) microanalysis, and powder X-ray diffraction techniques. A series of glasses was prepared while maintaining the ratio of yttrium-to-silicon-to-aluminium, but replacing oxygen with nitrogen up to the nitrogen solubility limit. On annealing at 1250 C, the oxide glass fully crystallized into yttrium disilicate (Y2Si2O7). Al2O3 and mullite (Al6Si2O13) while, with increasing nitrogen content, the disilicate phase was progressively replaced by yttrium aluminium garnet (Y3Al5O12) and nitrogen was mainly incorporated into Si2N2O. Annealing of the nitrogen glasses at 1100 C produced partial crystallization involving an intermediate phase related to nitrogen-wollastonite. Phase separation in an as-quenched SiO2-rich Y-Si-Al-O composition glass is illustrated. 9 references.

Optical Characterization of Zinc Modified Bismuth Silicate Glasses

Directory of Open Access Journals (Sweden)

Rajesh Parmar

2015-01-01

Full Text Available The optical characterization of glass samples in the system 40SiO2 · xZnO · (60-xBi2O3 with x=0, 5, 10, 15, 20, 25, 30, 35, and 40 prepared by conventional melt-quench technique has been carried out in the light of Hydrogenic Excitonic Model (HEM. The absorption coefficient spectra show good agreement with theoretical HEM for the present glass system and the values of different parameters like Eg, R, Γ1, Γc, and Co have been estimated from fitting of this model. The values of energy band gap estimated from fitting of HEM with experimental data are in good agreement with those obtained from Tauc’s plot for direct transitions. The band gap energy is found to increase with increase of ZnO content. The decrease in values of Urbach energy with increase in ZnO content indicates a decrease in defect concentration in the glass matrix on addition of ZnO content. Optical constants n and k obey k-k consistency and the dielectric response of the studied glass system is similar to that obtained for Classical Electron Theory of Dielectric Materials. The calculated values of the metallization criterion (M show that the synthesized glasses may be good candidates for new nonlinear optical materials.

Viscoelasticity of metallic, polymeric and oxide glasses

Energy Technology Data Exchange (ETDEWEB)

Pelletier, J.M. [GEMPPM, INSA Lyon, Bat. B. Pascal, 69621 Villeurbanne (France)]. E-mail: Jean-marc.Pelletier@insa-lyon.fr; Gauthier, C. [GEMPPM, INSA Lyon, Bat. B. Pascal, 69621 Villeurbanne (France); Munch, E. [GEMPPM, INSA Lyon, Bat. B. Pascal, 69621 Villeurbanne (France)

2006-12-20

Present work addresses on mechanical spectroscopy experiments performed on bulk metallic glasses (Zr-Ti-Cu-Ni-Be alloys, Mg-Y-Cu alloys), on oxide glasses (SiO{sub 2}-Na{sub 2}O-CaO) and on amorphous polymers (polyethylene terephtalate (PET), nitrile butadiene rubber (NBR), etc.). It appears that whatever the nature of the chemical bonding involved in the material, we observe strong relaxation effects in an intermediate temperature range, near the glass transition temperature. In addition, when crystallization occurs in the initially amorphous material, similar evolution is observed in all the materials. A method is proposed to properly separate elastic, viscoelastic and viscoplastic contributions to the deformation. Finally a physical model is given to describe these viscoelastic phenomena.

Radiation effects on transport and bubble formation in silicate glasses. 1998 annual progress report

International Nuclear Information System (INIS)

Trifunac, A.D.

1998-01-01

'To study the fundamental chemistry of radiation damage in silicate/borosilicate glasses and simulated high-level nuclear waste (HLW) forms. Special emphasis is on delineating molecular processes crucial for understanding the aggregation of defects and formation of oxygen bubbles. The knowledge obtained will provide the needed scientific basis for extrapolating long-term behavior of stored radiative waste glass forms. This report summarizes the first 6 months of a 3-year project. The following issues have been addressed: (i) the production of radiolytic oxygen, (ii) the chemistry of hydrogenous species, and (iii) the effect of glass composition and microstructure on the formation and accumulation of metastable point defects.'

Optical pumping production of spin polarized hydrogen

International Nuclear Information System (INIS)

Knize, R.J.; Happer, W.; Cecchi, J.L.

1984-01-01

There has been much interest recently in the production of large quantities of spin polarized hydrogen in various fields including controlled fusion, quantum fluids, high energy, and nuclear physics. One promising method for the development of large quantities of spin polarized hydrogen is the utilization of optical pumping with a laser. Optical pumping is a process where photon angular momentum is converted into electron and nuclear spin. The advent of tunable CW dye lasers (approx. 1 watt) allow the production of greater than 10 18 polarized atoms/sec. We have begun a program at Princeton to investigate the physics and technology of using optical pumping to produce large quantities of spin polarized hydrogen. Initial experiments have been done in small closed glass cells. Eventually, a flowing system, open target, or polarized ion source could be constructed

Development of glass compositions with 9% waste content for the vitrification of high-level waste from LWR nuclear reactors

International Nuclear Information System (INIS)

Lakatos, T.

1979-10-01

Reduction of the contents of waste in glass from 20-25% to 9% causes a decrease of the leaching resistance of the glass. The addition of Zn0 reduces the leaching values by a factor of approximately 10. The crystallized glass ceramics have a lower coefficient of thermal expansion than glassy waste bodies. The separation of the phase which contains Mo occurs during heat treatment. The amount of separated Mo is lower for low alkali sac type (Si0 2 - A1 2 0 3 -Ca0 system) of glasses by a factor of approximately 50. All the glasses were prepared with simulated waste composition. (GBn.)

Visible light driven multifunctional photocatalysis in TeO2-based semiconductor glass ceramics

Science.gov (United States)

Kushwaha, Himmat Singh; Thomas, Paramanandam; Vaish, Rahul

2017-01-01

Photocatalytic xCaCu3Ti4O12-(100-x)TeO2 (x=0.25 mol% to 3 mol%), glass nanocomposites were fabricated and investigated for wastewater treatment, self-cleaning surfaces, and photocatalytic hydrogen evolution. Visible light active crystals of Cu-doped TiO2 and TiTe3O8 were grown by optimized crystallization of as-quenched glasses. The visible light photocatalytic activity of glass samples was investigated for estrogenic pharmaceutical pollutants, and the degradation rate was obtained as 168.56 min-1 m-2. A higher photocatalytic H2 production rate was observed (135 μmole h-1 g-1) for the crystallized CaCu3Ti4O12-TeO2 (x=3. 0) glass plate under visible light. The self-cleaning performance was observed using contact angle measurements for water under dark and light conditions. These visible light active glass ceramics are a cost effective sustainable solution for water treatment and self-cleaning applications.

Recovery of palladium, cesium, and selenium from heavy metal alkali borosilicate glass by combination of heat treatment and leaching processes

Energy Technology Data Exchange (ETDEWEB)

Xu, Zhanglian; Okada, Takashi, E-mail: t-okada@u-fukui.ac.jp; Nishimura, Fumihiro; Yonezawa, Susumu

2017-06-05

Highlights: • A separation technique of both noble and less noble metal from glass is studied. • Via reductive heat treatment, 80% of palladium is extracted in liquid bismuth. • Sodium–potassium-rich materials with cesium and selenium are phase separated. • From the materials, over 80% of cesium and selenium are extracted in water. - Abstract: Reductive heat-treatment and leaching process were applied to a simulated lead or bismuth soda-potash-borosilicate glass with palladium, cesium, and selenium to separate these elements. In the reductive heat treatment, palladium is extracted in liquid heavy metal phase generated by the reduction of the heavy metal oxides, whereas cesium and selenium are concentrated in phase separated Na–K-rich materials on the glass surface. From the materials, cesium and selenium can be extracted in water, and the selenium extraction was higher in the treatment of the bismuth containing glass. The chemical forms of palladium in the glass affected the extraction efficiencies of cesium and selenium. Among the examined conditions, in the bismuth glass treatment, the cesium and selenium extraction efficiencies in water were over 80%, and that of palladium in liquid bismuth was over 80%.

A Failure Locus for Hydrogen Assisted Failure

DEFF Research Database (Denmark)

Fuentes-Alonso, Sandra; Harris, Zach D.; Burns, James T.

2017-01-01

of a hydrogen-dependent traction separation law. A special control algorithm is employed to overcome numerical instabilities intrinsically associated with cohesive zone formulations. The fracture energy is degraded by means of an experimentally-motivated hydrogen degradation relation. Numerical results provide...... important insight into the failure process, enabling to identify critical values of hydrogen concentration and remote stresses that trigger cracking. The work builds upon previous works by the authors and brings important insight into the technologically important problem of hydrogen assisted cracking....

High stability of palladium/kieselguhr composites during absorption/desorption cycling for hydrogen isotope separation

Energy Technology Data Exchange (ETDEWEB)

Lei, Yang, E-mail: lei.y@outlook.com; Liu, Xiaopeng; Li, Shuo; Jiang, Lijun; Zhang, Chao; Li, Shuai; He, Di; Wang, Shumao

2016-12-15

Highlights: • Pd/K composites with as high as 57 wt.% of Pd have been successfully prepared. • Palladium particles can be effectively packed into the pores of kieselguhr substrates. • Variation of heat-treatment temperatures hardly affect hydrogen absorption capacity and hydrogen saturation time of the Pd/K. • Anti-pulverization property of Pd/K can be improved by packing palladium into the kieselguhr internal pores and heating at 1300 °C. - Abstract: Palladium/kieselguhr (Pd/K) composites with 57 wt.% of Pd were prepared by an improved dipping and thermal decomposition method and heated at elevated temperature to reduce breakdown during hydrogenation-dehydrogenation cycles. The hydrogen absorption kinetic properties of the samples heated at different temperatures were tested under the condition of 20 °C with 100 kPa hydrogen pressure. The 1300 °C heated Pd/K composites were repeated up to 4010 absorption and desorption cycles at temperature ranges between −40 °C and 200 °C. The results show that the phase structure, hydrogen absorption capacity and hydrogen saturation time of the Pd/K were not affected by the change of heat-treated temperatures. And after heat treatment at 1300 °C, the Pd/K particles were strengthened and fraction of larger than 80 mesh were as high as 93.4%.

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

International Nuclear Information System (INIS)

J. Douglas Way; Robert L. McCormick

2001-01-01

Recent advances have shown that Pd-Cu composite membranes are not susceptible to the mechanical, embrittlement, and poisoning problems that have prevented widespread industrial use of Pd for high temperature H(sub 2) separation. These membranes consist of a thin ((approx)10(micro)m) film of metal deposited on the inner surface of a porous metal or ceramic tube. Based on preliminary results, thin Pd(sub 60)Cu(sub 40) films are expected to exhibit hydrogen flux up to ten times larger than commercial polymer membranes for H(sub 2) separation, and resist poisoning by H(sub 2)S and other sulfur compounds typical of coal gas. Similar Pd-membranes have been operated at temperatures as high as 750 C. The overall objective of the proposed project is to demonstrate the feasibility of using sequential electroless plating to fabricate Pd(sub 60)Cu(sub 40) alloy membranes on porous supports for H(sub 2) separation. These following advantages of these membranes for processing of coal-derived gas will be demonstrated: High H(sub 2) flux; Sulfur tolerant, even at very high total sulfur levels (1000 ppm); Operation at temperatures well above 500 C; and Resistance to embrittlement and degradation by thermal cycling. The proposed research plan is designed to providing a fundamental understanding of: Factors important in membrane fabrication; Optimization of membrane structure and composition; Effect of temperature, pressure, and gas composition on H(sub 2) flux and membrane selectivity; and How this membrane technology can be integrated in coal gasification-fuel cell systems

Review on heavy water separation at pilot scale

International Nuclear Information System (INIS)

Wuryanto; Soeroto Ronodirdjo.

1976-01-01

The isotope exchange system ammonia-water and hydrogen sulfide water dual temperature are studied. Comparison of the two methods with water electrolysis, water distillation, hydrogen distillation and catalytic water hydrogen exchange are discussed. Water distillation is a simple method. Electrolysis of water has the highest separation factor. The isotope exchange hydrogen sulfide water dual temperature will be done in accord with the report on the operation of a dual temperature single stage for deuterium concentration written by M.L.Eidinoff and C.F. Hiskey. (authors)

A study of positron properties in quartz crystals and synthetic silica glass

International Nuclear Information System (INIS)

Anwand, W.; Brauer, G.; Hesegawa, M.; Dersch, O.; Rauch, F.

2001-01-01

The monoenergetic positron beamline 'SPONSOR' at Rossendorf has been used to investigate the positron behaviour in a naturally grown Brasilian quartz, two synthetic quartz crystals of different origin, and synthetic silica glass. The measurements allow us to obtain the positron diffusion length of free positrons and Bloch para-positronium, if formed, in these materials. In addition, hydrothermal treatment of a synthetic quartz has been used to introduce hydrogen into the crystal up to a certain depth. The presence of hydrogen is found to influence the formation of para-positronium. The depth distribution of hydrogen has been measured independently by the nuclear reaction analysis, and will be discussed in comparison with the results deduced from the positron studies. (author)

Mechanistic interpretation of glass reaction: Input to kinetic model development

International Nuclear Information System (INIS)

Bates, J.K.; Ebert, W.L.; Bradley, J.P.; Bourcier, W.L.

1991-05-01

Actinide-doped SRL 165 type glass was reacted in J-13 groundwater at 90 degree C for times up to 278 days. The reaction was characterized by both solution and solid analyses. The glass was seen to react nonstoichiometrically with preferred leaching of alkali metals and boron. High resolution electron microscopy revealed the formation of a complex layer structure which became separated from the underlying glass as the reaction progressed. The formation of the layer and its effect on continued glass reaction are discussed with respect to the current model for glass reaction used in the EQ3/6 computer simulation. It is concluded that the layer formed after 278 days is not protective and may eventually become fractured and generate particulates that may be transported by liquid water. 5 refs., 5 figs. , 3 tabs

Glass formation, magnetic properties and magnetocaloric effect of ternary Ho–Al–Co bulk metallic glass

International Nuclear Information System (INIS)

Zhang, Huiyan; Li, Ran; Ji, Yunfei; Liu, Fanmao; Luo, Qiang; Zhang, Tao

2012-01-01

A ternary Ho–Al–Co system with high glass-forming ability (GFA) was developed and fully glassy rods with diameters up to 1 cm can be produced for the best glass former of Ho 55 Al 27.5 Co 17.5 alloy. The thermal stability and low-temperature magnetic properties of the Ho 55 Al 27.5 Co 17.5 bulk metallic glass (BMG) were studied. The magnetic transition temperature of this alloy is ∼14 K as determined by the thermomagnetic measurement. Two indicators, i.e. isothermal magnetic entropy change (ΔS M ) and the relative cooling power (RCP), were adopted to evaluate the magnetocaloric effect (MCE) of the alloy under a low magnetic field up to 2 T, which can be generated by permanent magnets. The values of |ΔS M | and RCP are 7.98 J kg −1 K −1 and 191.5 J kg −1 , respectively. The Ho 55 Al 27.5 Co 17.5 BMG with good MCE and high GFA provides an attractive candidate for magnetic refrigeration applications, like hydrogen liquefaction and storage. - Highlights: ► A ternary Ho–Al–Co BMG system with high glass-forming ability was developed. ► Fully glassy rods of Ho 55 Al 27.5 Co 17.5 alloy were produced up to 1 cm in diameter. ► The thermal stability and magnetic properties of the BMG were evaluated. ► The BMG exhibits good magnetocaloric effect under a low magnetic field up to 2 T.

High-quality global hydrogen silsequioxane contact planarization for nanoimprint lithography

NARCIS (Netherlands)

Büyükköse, S.; Vratzov, Boris; van der Wiel, Wilfred Gerard

2011-01-01

The authors present a novel global contact planarization technique based on the spin-on-glass material hydrogen silsequioxane (HSQ) and demonstrate its excellent performance on patterns of 70 nm up to several microns generated by UV-based nanoimprint lithography. The HSQ layer (∼165 nm) is spin

JAEA’s R&D on the Thermochemical Hydrogen Production IS Process

International Nuclear Information System (INIS)

Kasahara, Seiji; Tanaka, Nobuyuki; Noguchi, Hiroki; Iwatsuki, Jin; Takegami, Hiroaki; Yan, Xing L.; Kubo, Shinji

2014-01-01

Japan Atomic Energy Agency (JAEA) has studied iodine-sulfur (IS) process, a thermochemical cycle to produce hydrogen by water splitting. This process is a candidate application of high temperature heat from high temperature gas-cooled reactors. This paper outlines the IS process study in JAEA, in particular recent situation of the R&D. Reactor components and a total process facility are tested to evaluate their integrity. A Bunsen reactor, a H_2SO_4 decomposer and a HI decomposer made of industrial materials such as SiC ceramic, fluoroplastic and lining materials have been examined separately as reactor components. A semibatch test and a thermal cycle test were operated in the Bunsen reactor. H_2SO_4 decomposition test is in a bayonet type reactor and HI decomposition test in an adiabatic radial flow type reactor are now under way. On the basis of a demonstration of continuous hydrogen production of 31 NL/h by a glass apparatus, an experimental apparatus of the total IS process has just been constructed to verify integrity of process components of industrial materials, H_2 production scale of which is 200 NL/h. Electro-electrodialysis (EED) cells to concentrate HI before distillation and a SiC-made bayonet type H_2SO_4 decomposer are applied in the facility. Process data of EED cells has been collected aiming to improve H_2 production thermal efficiency. Influence of temperature, composition in solution and existence of impurities on the cell properties has been investigated. Reduction of heat input to a HI separation step by applying the results of the study was shown. (author)

New hydrogen technologies

International Nuclear Information System (INIS)

1992-01-01

This report presents an overview of the overall hydrogen system. There are separate sections for production, distribution, transport, storage; and applications of hydrogen. The most important methods for hydrogen production are steam reformation of natural gas and electrolysis of water. Of the renewable energy options, production of hydrogen by electrolysis using electricity from wind turbines or by gasification of biomass were found to be the most economic for Finland. Direct use of this electricity or the production of liquid fuels from biomass will be competing alternatives. When hydrogen is produced in the solar belt or where there is cheap hydropower it must be transported over long distances. The overall energy consumed for the transport is from 25 to 40 % of the initial available energy. Hydrogen storage can be divided into stationary and mobile types. The most economic, stationary, large scale hydrogen storage for both long and short periods is underground storage. When suitable sites are not available, then pressure vessels are the best for short period and liquid H 2 for long period. Vehicle storage of hydrogen is by either metal hydrides or liquid H 2 . Hydrogen is a very versatile energy carrier. It can be used to produce heat directly in catalytic burners without flame, to produce electricity in fuel cells with high efficiency for use in vehicles or for peak power shaving, as a fuel component with conventional fuels to reduce emissions, as a way to store energy and as a chemical reagent in reactions

From glass to crystal - Nucleation, growth and de-mixing, from research to applications

International Nuclear Information System (INIS)

Neuville, Daniel R.; Cormier, Laurent; Caurant, Daniel; Montagne, Lionel; Charpentier, Thibault; Chevalier, Jerome; Comte, Monique; Dargaud, Olivier; Ligny, Dominique de; Deniard, Philippe; Dussardier, Bernard; Dussauze, Marc; Fargin, Evelyne; Gremillard, Laurent; Gredin, Patrick; Jousseaume, Cecile; Lafait, Jacques; Lancry, Mathieu; Lefebvre, Leila; Levelut, Claire; Magallanes-Pedromo, Marlin; Massiot, Dominique; Mear, Francois O.; Meille, Sylvain; Meng, Nicolas; Mortier, Michel; Papin, Sophie; Papon, Gautier; Pastouret, Main; Petit, Yannick; Poumellec, Bertrand; Pradel, Annie; Reillon, Vincent; Rodriguez, Vincent; Rogez, Jacques; Roussel, Pascal; Royon, Arnaud; Schuller, Sophie; Tricot, Gregory; Vigouroux, Helene

2013-01-01

This book first presents the conventional nucleation theory: vitrification, homogeneous and heterogeneous nucleation, induction time, crystal growth, Oswald law. The second part addresses the evolutions beyond this theory: cluster dynamics, validity of the Stokes-Einstein relationship, non conventional germ system, Gibbs generalized approach, two-stage model. The third part addresses the thermodynamic stability and the global kinetics of transformation: thermodynamic stability and instability of a vitreous system, phenomenological approach to transformation kinetics. The fourth part addresses the de-mixing process on glasses: thermodynamic description of phase separation, de-mixing kinetics, influence of glass structure on de-mixing trend, de-mixing characterisation. The next parts describe the crystal-chemical approach to the main crystalline phases noticed in glass-ceramics (silicate phases and phosphates), the elaboration and control of glass-ceramic microstructure (controllable parameters, elaboration processes, characterization methods, microstructure types, design of glass-ceramics with desired properties by control of crystallisation mechanisms), X ray diffraction in the case of glass-ceramics, calorimetry and differential thermal analysis for the study of glass ceramics, the application of electronic microscopy to the study of nucleation and crystallisation in glasses, small-angle scattering of X rays and neutrons, the use of nuclear magnetic resonance to understand the disorder and crystallisation in vitreous materials, the use of Raman spectrometry to study mechanisms of nucleation and crystal growth, large instruments aimed at an in situ approaches to crystallisation, commercial applications of glass-ceramics, applications of biomaterials in glass and glass-ceramics, the coloration of metal nanoparticles, transparent glass-ceramics, the formation and applications of nanoparticles in silica-based optic fibres, the both-way relationship between non linear

Calorimetric signature of structural heterogeneity in a ternary silicate glass

DEFF Research Database (Denmark)

Zhang, Yanfei; Yang, G.; Yue, Yuanzheng

2013-01-01

We investigate the structural heterogeneity in a silicate glass by hyperquenching–annealing–calorimetry approach. The results show a striking phenomenon: two separated sub-Tg relaxation peaks appear on the calorimetric curve of the hyperquenched CaO–MgO–SiO2 glass, implying the existence of two...... distinct structural domains of higher and lower potential energies, respectively. The higher energy domains in nanoscale are so unstable that they become ordered during hyperquenching. This is verified by the high-resolution transmission electron microscopy image exhibiting nanoordered domains in the glass...... matrix. The higher energy domains relax similar to a strong glass phase, whereas the lower energy domains do similar to a fragile one....

Pd Alloy Membranes for Hydrogen Separation from Coal-Derived Syngas

National Research Council Canada - National Science Library

Alptekin, Gokhan O; DeVoss, Sarah; Amalfitano, Bob; Way, Douglas; Thoen, Paul; Lusk, Mark

2006-01-01

TDA Research Inc., in collaboration with Colorado School of Mines (CSM) is developing a sulfur and CO-tolerant membrane to produce the clean hydrogen from syngas using Pd membrane films prepared on a variety of supports (e.g...

Isotope effect in the diffusion of hydrogen and deuterium in polymers

Energy Technology Data Exchange (ETDEWEB)

Toi, K.; Takeuchi, K.; Tokuda, T.

1980-02-01

Temperature dependences of diffusion and permeation coefficients of hydrogen and deuterium in glassy and rubbery polymer films have been measured. The size of the free volume element in rubbery polymers has been calculated according to the theory of Frisch and Rogers for the quantum isotope effect, but the free volume is too large for precise calculation below the glass-transition temperature. The cooperative movement of segments is also discussed using the ratio of preexponential factors for diffusion mechanisms above and below the glass-transition temperature.

Hydrogen energy applications

International Nuclear Information System (INIS)

Okken, P.A.

1992-10-01

For the Energy and Material consumption Scenarios (EMS), by which emission reduction of CO 2 and other greenhouse gases can be calculated, calculations are executed by means of the MARKAL model (MARket ALlocation, a process-oriented dynamic linear programming model to minimize the costs of the energy system) for the Netherlands energy economy in the period 2000-2040, using a variable CO 2 emission limit. The results of these calculations are published in a separate report (ECN-C--92-066). The use of hydrogen can play an important part in the above-mentioned period. An overview of several options to produce or use hydrogen is given and added to the MARKAL model. In this report techno-economical data and estimates were compiled for several H 2 -application options, which subsequently also are added to the MARKAL model. After a brief chapter on hydrogen and the impact on the reduction of CO 2 emission attention is paid to stationary and mobile applications. The stationary options concern the mixing of natural gas with 10% hydrogen, a 100% substitution of natural gas by hydrogen, the use of a direct steam generator (combustion of hydrogen by means of pure oxygen, followed by steam injection to produce steam), and the use of fuel cells. The mobile options concern the use of hydrogen in the transportation sector. In brief, attention is paid to a hydrogen passenger car with an Otto engine, and a hydrogen passenger car with a fuel cell, a hybrid (metal)-hydride car, a hydrogen truck, a truck with a methanol fuel cell, a hydrogen bus, an inland canal boat with a hydrogen fuel cell, and finally a hydrogen airplane. 2 figs., 15 tabs., 1 app., 26 refs

SPE (tm) regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications

Science.gov (United States)

Mcelroy, J. F.

1990-01-01

Viewgraphs on SPE regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications are presented. Topics covered include: hydrogen-oxygen regenerative fuel cell energy storage system; electrochemical cell reactions; SPE cell voltage stability; passive water removal SPE fuel cell; fuel cell performance; SPE water electrolyzers; hydrophobic oxygen phase separator; hydrophilic/electrochemical hydrogen phase separator; and unitized regenerative fuel cell.

Structural role of molybdenum in nuclear glasses: an EXAFS study

International Nuclear Information System (INIS)

Calas, G.; Le Grand, M.; Galoisy, L.; Ghaleb, D.

2003-01-01

The Mo environment has been investigated in inactive nuclear glasses using extended X-ray absorption spectroscopy (XAS). Mo is present in a tetrahedron coordinated to oxygen in the form of molybdate groups [MoO 4 ] 2- (d(Mo-O)=1.78 A). This surrounding is not affected by the presence of noble metal phases in the nuclear glass. Relying on the XAS results, on the bond-valence model and on molecular dynamics simulations of a simplified borosilicate model glass, we show that these groups are not directly linked to the borosilicate network but rather located within alkali and alkaline-earth rich domains in the glass. This specific location in the glass network is a way to understand the low solubility of Mo in glasses melted under oxidizing conditions. It also explains the possible phase separation of a yellow phase enriched in alkali molybdates in molten nuclear glasses or the nucleation of calcium molybdates during thermal aging of these glasses. Boron coordination changes in the molten and the glassy states may explain the difference in the composition of the crystalline molybdates, as they exert a direct influence on the activity of alkalis in borosilicate glasses and melts

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)

Preparation of lead oxide nanoparticles from cathode-ray tube funnel glass by self-propagating method.

Science.gov (United States)

Wang, Yu; Zhu, Jianxin

2012-05-15

This paper presents a novel process of extracting lead oxide nanoparticles from cathode-ray tube (CRT) funnel glass using self-propagating high-temperature synthesis (SHS) method. The impacts of added amount of funnel glass on the extraction ratio of lead, the lead extraction velocity and the micromorphology, as well as particle size of extracted nanoparticles were investigated. We found that self-propagating reaction in the presence of Mg and Fe(2)O(3) could separate lead preferentially and superfine lead oxide nanoparticles were obtained from a collecting chamber. The separation ratio was related closely to the amount of funnel glass added in the original mixture. At funnel glass addition of no more than 40wt.%, over 90wt.% of lead was recovered from funnel glass. High extraction yield reveals that the network structure of funnel glass was fractured due to the dramatic energy generated during the SHS melting process. The PbO nanoparticles collected show good dispersion and morphology with a mean grain size of 40-50nm. Copyright © 2012 Elsevier B.V. All rights reserved.

Glass consistency and glass performance

International Nuclear Information System (INIS)

Plodinec, M.J.; Ramsey, W.G.

1994-01-01

Glass produced by the Defense Waste Processing Facility (DWPF) will have to consistently be more durable than a benchmark glass (evaluated using a short-term leach test), with high confidence. The DWPF has developed a Glass Product Control Program to comply with this specification. However, it is not clear what relevance product consistency has on long-term glass performance. In this report, the authors show that DWPF glass, produced in compliance with this specification, can be expected to effectively limit the release of soluble radionuclides to natural environments. However, the release of insoluble radionuclides to the environment will be limited by their solubility, and not glass durability

Liquid hydrogen production via hydrogen sulfide methane reformation

Energy Technology Data Exchange (ETDEWEB)

Huang, Cunping; T-Raissi, Ali [University of Central Florida, Florida Solar Energy Center, 1769 Clearlake Road, Cocoa, FL 32922 (United States)

2008-01-03

Hydrogen sulfide (H{sub 2}S) methane (CH{sub 4}) reformation (H{sub 2}SMR) (2H{sub 2}S + CH{sub 4} = CS{sub 2} + 4H{sub 2}) is a potentially viable process for the removal of H{sub 2}S from sour natural gas resources or other methane containing gases. Unlike steam methane reformation that generates carbon dioxide as a by-product, H{sub 2}SMR produces carbon disulfide (CS{sub 2}), a liquid under ambient temperature and pressure - a commodity chemical that is also a feedstock for the synthesis of sulfuric acid. Pinch point analyses for H{sub 2}SMR were conducted to determine the reaction conditions necessary for no carbon lay down to occur. Calculations showed that to prevent solid carbon formation, low inlet CH{sub 4} to H{sub 2}S ratios are needed. In this paper, we analyze H{sub 2}SMR with either a cryogenic process or a membrane separation operation for production of either liquid or gaseous hydrogen. Of the three H{sub 2}SMR hydrogen production flowsheets analyzed, direct liquid hydrogen generation has higher first and second law efficiencies of exceeding 80% and 50%, respectively. (author)

Hydrogen separation from high temperature CO-containing syn-gas flow using molecular ceramic membranes

Energy Technology Data Exchange (ETDEWEB)

Soudarev, A.; Konakov, G.; Souryaninov, A.; Molchanov, A. [Boyko Research Engineering Ceramic Heat Engines Center Ltd., St. Petersburg (Russian Federation); Lelait, L.; Stevens, P.H. [European Inst. for Power Studies, Karlsruhe (Germany)

2006-07-01

Poisoning of the platinum (Pt) metals used as catalysts for proton exchange membrane fuel cells (PEMFCs) can negatively impact on PEMFC operation efficiency. In order to address this issue, a supply of hydrogen with a carbon monoxide (CO) admixtures is required. This paper provided details of a new type of molecular ceramic membrane (MCM) that allows the separation of hydrogen (H{sub 2}) from the hydrocarbon fuel reforming products that contain CO and has higher temperature and pressure capacity than other membranes. After various tests, alumo-magnesium spinel (AMS) was selected as the most promising porous material for the ceramic multi-layer membrane. The crystalline structure of the AMS showed good thermo-dynamic stability during tests that ranged between 20 and 1400 degrees C, as well as a chemical resistance relative to the effects of the aggressive fuel cell environment, and no exposure to the oxidation-recovery processes in the CO and H{sub 2} flow. The macroporous substrate of the AMS and the membrane selection layers have the same composition. The formation of the carrier was conducted by a semi-dry molding on a hydraulic press. Formation of the nano-porous structure in the carrier macro-pores by the polysilicon acid sol solution treatment allowed the synthesis of the amorphous silica and crystobalite crystals with a developed surface and nano-dimension subporosity. Test results have shown that the MCM has optimum penetrability and selectivity values as well as admissible thermo-mechanical properties. H{sub 2} flow through the membrane was 1.5-1.7 times greater than the CO flow. It was concluded that the AMS-based membrane devices will increase the efficiency of the PEMFC power plants and reduce their degradation capacity. 2 refs., 1 tab., 1 fig.

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

Replication technique for examining defects in the interface of a metal-to-glass ceramic bond

International Nuclear Information System (INIS)

Spears, R.K.

1978-01-01

Epoxy replicas were made of the interface of a molybdenum and glass-ceramic assembly and examined by scanning electron microscopy. Replications of this interface were produced by first removing the molybdenum from four assemblies using a nitric acid-based etchant. The glass-ceramic insulators that remained were pressure encapsulated in epoxy. After curing, the glass-ceramics were etched from the epoxy in an hydrogen fluoride-based acid etchant. The resulting replicas resembled the texture of the molybdenum surface with the interface defects shown in detail as projections. This process revealed some unusual interface problems which appeared to be associated with the evolution of gas from the molybdenum piece parts

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

Separation of tritium from gaseous and aqueous effluent systems

International Nuclear Information System (INIS)

Kobisk, E.H.

1977-01-01

Three processes are discussed for separating tritium from gaseous and aqueous effluent systems: separation in the gas phase using Pd-25 wt percent Ag alloy diffusion membranes; electrolytic separation in the aqueous phase using ''bipolar'' electrodes; and the countercurrent exchange of tritium-containing hydrogen gas with water on catalytic surfaces combined with separation by direct electrolysis

Nanomaterials for Hydrogen Storage

Indian Academy of Sciences (India)

concepts transferred from the gaseous state. Separation of a ... molecular mass to that calculated by colligative methods. It is important in ... namics is vital in the design and optimization of the materials for hydrogen ... vehicular applications.

OD bands in the IR spectra of a deuterated soda-lime-silica glass

Energy Technology Data Exchange (ETDEWEB)

Peuker, C.; Brzezinka, K.W.; Gaber, M.; Kohl, A.; Geissler, H. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

2001-07-01

IR spectra of a deuterated glass of the composition (in mol%) 16 Na{sub 2}O . 10 CaO . 74 SiO{sub 2} complete earlier spectroscopic studies on water-poor soda-lime-silica glasses. The approved IR spectroscopic method of the deuterium exchange allows a reliable assignment of the hydroxyl bands also in the case of glasses. By spectra comparison the assignment of the IR bands at 3500 and 2800 cm{sup -1} to hydroxyl groups with different hydrogen bonding is verified. The IR band at about 4500 cm{sup -1} is interpreted as both a combination of the stretching vibrations {nu}O-H and {nu}Si-OH and a combination of the stretching vibration {nu}O-H and the deformation vibration {delta}SiOH. The bands at 1763 and 1602 cm{sup -1} are attributed to combination vibrations of the glass network. (orig.)

Preparation of high-purity Pr(3+) doped Ge–Ga–Sb–Se glasses with intensive middle infrared luminescence

Energy Technology Data Exchange (ETDEWEB)

Karaksina, E.V.; Shiryaev, V.S., E-mail: shiryaev@ihps.nnov.ru; Kotereva, T.V.; Churbanov, M.F.

2016-02-15

Glass materials with high emission characteristics and low content of limiting impurities are required for creation of devices for middle infrared (mid-IR) fiber optics. The paper presents the results of preparation of high-purity Pr{sup 3+}-doped Ga{sub x}Ge{sub y}Sb{sub z}Se{sub 1−(x+y+z)} (x=3÷4, y=20÷26, z=5÷11) glasses. The multi-stage technique for synthesis of these glasses is developed. It is based on chemical distillation purification of glass components and the transport reaction for purification of gallium. Transmitting, as well as thermal and luminescent properties of glasses are investigated. The content of limiting impurities of oxygen, carbon and hydrogen in the glass samples was ≤0.2 ppm wt. The 1300–3000 ppm wt Pr{sup 3+}-doped Ga–Ge–Sb–Se bulk glasses exhibit an intensive photoluminescence in the spectral range of 3.5–5.5 μm.

Thermodynamical modeling of nuclear glasses: coexistence of amorphous phases

International Nuclear Information System (INIS)

Adjanor, G.

2007-11-01

Investigating the stability of borosilicate glasses used in the nuclear industry with respect to phase separation requires to estimate the Gibbs free energies of the various phases appearing in the material. In simulation, using current computational resources, a direct state-sampling of a glassy system with respect to its ensemble statistics is not ergodic and the estimated ensemble averages are not reliable. Our approach consists in generating, at a given cooling rate, a series of quenches, or paths connecting states of the liquid to states of the glass, and then in taking into account the probability to generate the paths leading to the different glassy states in ensembles averages. In this way, we introduce a path ensemble formalism and calculate a Landau free energy associated to a glassy meta-basin. This method was validated by accurately mapping the free energy landscape of a 38-atom glassy cluster. We then applied this approach to the calculation of the Gibbs free energies of binary amorphous Lennard-Jones alloys, and checked the correlation between the observed tendencies to order or to phase separate and the computed Gibbs free energies. We finally computed the driving force to phase separation in a simplified three-oxide nuclear glass modeled by a Born-Mayer-Huggins potential that includes a three-body term, and we compared the estimated quantities to the available experimental data. (author)

Effects of magnesium minerals representative of the Callovian-Oxfordian clay-stone on borosilicate glass alteration

International Nuclear Information System (INIS)

Debure, M.

2012-01-01

Borosilicate glasses dissolution has been studied in presence of magnesium minerals. Those minerals (dolomite, illite, smectite...) belong to the Callovo-Oxfordian (COx) clay-stone layer, studied in France as a potential site for nuclear waste disposal. Such minerals contain magnesium, an element able to sustain glass alteration when it is available in solution. In the confined media of the wastes disposal, the solids reactivity controls the solution composition and can be the driving force of nuclear glass alteration. Experiments show that magnesium carbonates (hydro-magnesite and dolomite) increase in the glass alteration: the precipitation of magnesium silicates consumes silicon which slows down the formation of the glass passivating layer. The lower the magnesium mineral solubility, the lower the glass alteration. The purified clay phases (illite, smectite...) from the COx layer increase the glass alteration. Half the magnesium was replaced by sodium during the purification process. In such conditions, the effect of clay phases on glass alteration is in part due to the acidic pH-buffering effect of the clay fraction. The GRAAL model implemented in the geochemical transport code HYTEC has confirmed and quantified the mechanisms put in evidence in the experiments. Cells diffusion experiments where the two solids were separated by an inert diffusion barrier allow to valid reactive transport modelling. Such experiments are more representative of the glass package which will be separated from the COx by corrosion products. They show that glass alteration rate is reduced when solids are not close. (author) [fr

The kinetics of Cr layer coated on TiNi films for hydrogen absorption

Indian Academy of Sciences (India)

Abstract. The effect of hydrogen absorption on electrical resistance with temperature ... pressure by thermal evaporation on the glass substrate at room temperature. ... and charging rate becomes faster in comparison to FeTi and TiNi thin films.

Optical hydrogen sensors based on metal-hydrides

Science.gov (United States)

Slaman, M.; Westerwaal, R.; Schreuders, H.; Dam, B.

2012-06-01

For many hydrogen related applications it is preferred to use optical hydrogen sensors above electrical systems. Optical sensors reduce the risk of ignition by spark formation and are less sensitive to electrical interference. Currently palladium and palladium alloys are used for most hydrogen sensors since they are well known for their hydrogen dissociation and absorption properties at relatively low temperatures. The disadvantages of palladium in sensors are the low optical response upon hydrogen loading, the cross sensitivity for oxygen and carbon, the limited detection range and the formation of micro-cracks after some hydrogen absorption/desorption cycles. In contrast to Pd, we find that the use of magnesium or rear earth bases metal-hydrides in optical hydrogen sensors allow tuning of the detection levels over a broad pressure range, while maintaining a high optical response. We demonstrate a stable detection layer for detecting hydrogen below 10% of the lower explosion limit in an oxygen rich environment. This detection layer is deposited at the bare end of a glass fiber as a micro-mirror and is covered with a thin layer of palladium. The palladium layer promotes the hydrogen uptake at room temperature and acts as a hydrogen selective membrane. To protect the sensor for a long time in air a final layer of a hydrophobic fluorine based coating is applied. Such a sensor can be used for example as safety detector in automotive applications. We find that this type of fiber optic hydrogen sensor is also suitable for hydrogen detection in liquids. As example we demonstrate a sensor for detecting a broad range of concentrations in transformer oil. Such a sensor can signal a warning when sparks inside a high voltage power transformer decompose the transformer oil over a long period.

Direction of CRT waste glass processing: electronics recycling industry communication.

Science.gov (United States)

Mueller, Julia R; Boehm, Michael W; Drummond, Charles

2012-08-01

Cathode Ray Tube, CRT, waste glass recycling has plagued glass manufacturers, electronics recyclers and electronics waste policy makers for decades because the total supply of waste glass exceeds demand, and the formulations of CRT glass are ill suited for most reuse options. The solutions are to separate the undesirable components (e.g. lead oxide) in the waste and create demand for new products. Achieving this is no simple feat, however, as there are many obstacles: limited knowledge of waste glass composition; limited automation in the recycling process; transportation of recycled material; and a weak and underdeveloped market. Thus one of the main goals of this paper is to advise electronic glass recyclers on how to best manage a diverse supply of glass waste and successfully market to end users. Further, this paper offers future directions for academic and industry research. To develop the recommendations offered here, a combination of approaches were used: (1) a thorough study of historic trends in CRT glass chemistry; (2) bulk glass collection and analysis of cullet from a large-scale glass recycler; (3) conversations with industry members and a review of potential applications; and (4) evaluation of the economic viability of specific uses for recycled CRT glass. If academia and industry can solve these problems (for example by creating a database of composition organized by manufacturer and glass source) then the reuse of CRT glass can be increased. Copyright © 2012 Elsevier Ltd. All rights reserved.

Isotope exchange between gaseous hydrogen and uranium hydride powder

International Nuclear Information System (INIS)

Shugard, Andrew D.; Buffleben, George M.; Johnson, Terry A.; Robinson, David B.

2014-01-01

Highlights: • Isotope exchange between hydrogen gas and uranium hydride powder can be rapid and reversible. • Gas–solid exchange rate is controlled by transport within ∼0.7 μm hydride particles. • Gas chromatographic separation of hydrogen isotopes using uranium hydride is feasible. - Abstract: Isotope exchange between gaseous hydrogen and solid uranium hydride has been studied by flowing hydrogen (deuterium) gas through packed powder beds of uranium deuteride (hydride). We used a residual gas analyzer system to perform real-time analysis of the effluent gas composition. We also developed an exchange and transport model and, by fitting it to the experimental data, extracted kinetic parameters for the isotope exchange reaction. Our results suggest that, from approximately 70 to 700 kPa and 25 to 400 °C, the gas-to-solid exchange rate is controlled by hydrogen and deuterium transport within the ∼0.7 μm diameter uranium hydride particles. We use our kinetic parameters to show that gas chromatographic separation of hydrogen and deuterium using uranium hydride could be feasible

Glass transition on the development of a hydrogen-bond network in nano-channel ice, and subsequent phase transitions of the ordering of hydrogen atom positions within the network in [Co(H{sub 2}bim){sub 3}](TMA){center_dot}20H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Keisuke [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551 (Japan); Oguni, Masaharu [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551 (Japan); Tadokoro, Makoto [Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Oohata, Yuki [Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Nakamura, Ryouhei [Department of Chemistry, Graduate School of Science, Osaka Municipal University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan)

2006-09-20

Low-temperature thermal properties of crystalline [Co(H{sub 2}bim){sub 3}](TMA){center_dot}20H{sub 2}O were studied by adiabatic calorimetry, where H{sub 2}bim is 2,2'-biimidazole, TMA is 1,3,5-benzene tricarboxylic acid, and 20H{sub 2}O represents the water forming nano-channel in the crystal. A glass transition was observed at T{sub g} = 107 K. It was discussed as a freezing-in phenomenon of a small number of water molecules remaining partially disordered in their positional arrangement. The possibility that some defects really remain in the hydrogen-bond network of channel water was mentioned. Two subsequent phase transitions were observed at 54.8 and 59 K. These were interpreted as being of a (super-structural commensurate)-incommensurate-(normal commensurate) type in the heating direction with respect to the hydrogen-atom positions as referred to the periodicity of the hydrogen-bond network. The transition entropy was evaluated to be 0.65 J K{sup -1}(H{sub 2}O-mol){sup -1} as a total of the two, indicating that the disorder of the hydrogen atoms is present only in part of the water molecules of the channel. Based on the fact that the excess heat capacity due to the equilibrium phase transition is observed down to 35-40 K, the relaxation time for the rearrangement of the hydrogen-atom positions was assumed at the longest to be 1 ks at 35 K. This indicates that the activation energy of the rearrangement amounts to at most 13 kJ mol{sup -1} and that the transfer of Bjerrum defects is attributed to the rearrangement.

A new technology for separation and recovery of materials from waste printed circuit boards by dissolving bromine epoxy resins using ionic liquid

International Nuclear Information System (INIS)

Zhu, P.; Chen, Y.; Wang, L.Y.; Qian, G.Y.; Zhou, M.; Zhou, J.

2012-01-01

Highlights: ► WPCBs were heated in [EMIM + ][BF 4 − ] for recovering solider at 240 °C. ► The bromine epoxy resins in WPCBs were all dissolved in [EMIM + ][BF 4 − ] at 260 °C. ► Used [EMIM + ][BF 4 − ] is treated by water to obtain regeneration. - Abstract: Recovery of valuable materials from waste printed circuit boards (WPCBs) is quite difficult because WPCBs is a heterogeneous mixture of polymer materials, glass fibers, and metals. In this study, WPCBs was treated using ionic liquid (1-ethyl-3-methylimizadolium tetrafluoroborate [EMIM + ][BF 4 − ]). Experimental results showed that the separation of the solders went to completion, and electronic components (ECs) were removed in WPCBs when [EMIM + ][BF 4 − ] solution containing WPCBs was heated to 240 °C. Meanwhile, metallographic observations verified that the WPCBs had an initial delamination. When the temperature increased to 260 °C, the separation of the WPCBs went to completion, and coppers and glass fibers were obtained. The used [EMIM + ][BF 4 − ] was treated by water to generate a solid–liquid suspension, which was separated completely to obtain solid residues by filtration. Thermal analyses combined with infrared ray spectra (IR) observed that the solid residues were bromine epoxy resins. NMR (nuclear magnetic resonance) showed that hydrogen bond played an important role for [EMIM + ][BF 4 − ] dissolving bromine epoxy resins. This clean and non-polluting technology offers a new way to recycle valuable materials from WPCBs and prevent environmental pollution from WPCBs effectively.

Spectrophotometric study of bio-sorption of uranium on glass grade spodumene shell powder

International Nuclear Information System (INIS)

Parakudyil, A.S.; Pillai, A.K.; Reddy, A.V.R.; Singal, R.K.; Sharma, P.K.; Michael, K.M.

2012-01-01

Separation of uranium found in iron ore leachates was done by extraction chromatography using glass grade spodumene shellpowder (GSS) in nitric acid medium and analyzed spectrophotometrically. The influences of metal ion concentration, pH and adsorption capacity of biomass were investigated. Biosorption is a potential method of separation of heavy and trace metals from waste water and effluents from various sources. The adsorption capacities of biomass were investigated by batch experiments and column experiments. In the present study, glass grade spodumene shell powder (GSS) in acidic medium is being used as a biosorbent

Long-term behavior of glass-ceramic zirconolite

International Nuclear Information System (INIS)

Martin, Ch.

2003-01-01

This work is a part of the investigation of new containment matrices considered for specific conditioning of radionuclides after separation. The aim was to demonstrate the long-term aqueous corrosion resistance of the glass-ceramic zirconolite considered for the conditioning of plutonium and the minor actinides. This material is composed of crystals of zirconolite (CaZrTi 2 O 7 ) dispersed in a residual vitreous phase. It appears that glass-ceramic zirconolite presents a better kinetic behavior than the nuclear glass R 7T7. This is mainly due to a more important rate decrease that occurs more rapidly, that induces a quantity of glass altered at least 10 times as small as for R 7T7 glass. This high slowdown of the alteration rate is attributed to the formation of an alteration film that has been the subject of a specific study. We have demonstrated that the rate decrease was controlled as for the R7T7 glass by the amorphous phase of the alteration film forming a diffusion barrier for reactive species. It seems that the porosity is not the single parameter that explains the protective effect of the gel. The main differences compared with R7T7 glass are that silicon does not control the alteration of the material and that the gel is composed of two distinct phases. We have in particular identified a dense phase enriched in titanium and neodymium that probably influences deeply the kinetics. (author)

Phase separation and structure formation in gadolinium based liquid and glassy metallic alloys

International Nuclear Information System (INIS)

Han, Junhee

2014-01-01

In this PhD research the liquid-liquid phase separation phenomena in Gd-based alloys was investigated in terms of phase equilibria, microstructure formation upon quenching the melt and corresponding magnetic properties of phase-separated metallic glasses. The phase diagrams of the binary subsystems Gd-Zr and Gd-Ti were experimentally reassessed. Especially the phase equilibria with the liquid phase could be determined directly by combining in situ high energy synchrotron X-ray diffraction with electrostatic levitation of the melt. The Gd-Zr system is of eutectic type with a metastable miscibility gap. The eutectic composition at 18 ± 2 at.% Zr, the liquidus line and the coexistence of bcc-Zr and bcc-Gd at elevated temperature could be determined. The Gd-Ti system is a monotectic system. The experimental observations in this work led to improved new Gd-Zr and Gd-Ti phase diagrams. The phase equilibria of the ternary Gd-Ti-Co system were analyzed for two alloy compositions. The XRD patterns for molten Gd 35 Ti 35 Co 30 gave direct evidence for the coexistence of two liquid phases formed by liquid-liquid phase separation. The first experimental and thermodynamic assessment of the ternary Gd-Ti-Co system revealed that the stable miscibility gap of binary Gd-Ti extends into the ternary Gd-Ti-Co system (up to about 30 at.% Co). New phase-separated metallic glasses were synthesized in Gd-TM-Co-Al (TM = Hf, Ti or Zr) alloys. The microstructure was characterized in terms of composition and cooling rate dependence of phase separation. Due to large positive enthalpy of mixing between Gd on the one side and Hf, Ti or Zr on the other side, the alloys undergo liquid-liquid phase separation during rapid quenching the melt. The parameters determining the microstructure development during phase separation are the thermodynamic properties of the liquid phase, kinetic parameters and quenching conditions. By controlling these parameters and conditions the microstructure can be

Heterogeneous Catalysis: Deuterium Exchange Reactions of Hydrogen and Methane

Science.gov (United States)

Mirich, Anne; Miller, Trisha Hoette; Klotz, Elsbeth; Mattson, Bruce

2015-01-01

Two gas phase deuterium/hydrogen exchange reactions are described utilizing a simple inexpensive glass catalyst tube containing 0.5% Pd on alumina through which gas mixtures can be passed and products collected for analysis. The first of these exchange reactions involves H[subscript 2] + D[subscript 2], which proceeds at temperatures as low as 77…

Multisample conversion of water to hydrogen by zinc for stable isotope determination

Science.gov (United States)

Kendall, C.; Coplen, T.B.

1985-01-01

Two techniques for the conversion of water to hydrogen for stable isotope ratio determination have been developed that are especially suited for automated multisample analysis. Both procedures involve reaction of zinc shot with a water sample at 450 ??C. in one method designed for water samples in bottles, the water is put in capillaries and is reduced by zinc in reaction vessels; overall savings in sample preparation labor of 75% have been realized over the standard uranium reduction technique. The second technique is for waters evolved under vacuum and is a sealed-tube method employing 9 mm o.d. quartz tubing. Problems inherent with zinc reduction include surface inhomogeneity of the zinc and exchange of hydrogen both with the zinc and with the glass walls of the vessels. For best results, water/zinc and water/glass surface area ratios of vessels should be kept as large as possible.

MoSx-coated NbS2 nanoflakes growth on glass carbon: an advanced electrocatalyst for the hydrogen evolution reaction

KAUST Repository

Zhou, Xiaofeng; Lin, Shi-Hsin; Yang, Xiulin; Li, Henan; Hedhili, Mohamed N.; Li, Lain-Jong; Zhang, Wenjing; Shi, Yumeng

2018-01-01

Recent experimental and theoretical studies have demonstrated that two-dimensional (2D) transition metal dichalcogenide (TMDC) nanoflakes are one of the most promising candidates for non-noblemetal electrocatalysts for hydrogen evolution reaction (HER). However, it is still demanding to optimize their conductivity and enrich active sites for the high efficient electrochemical performance. Herein, we report a chemical vapor deposition (CVD) and thermal annealing two-step strategy to controllably synthesize hybrid electrocatalysts consisting of metallic NbS2 nanoflake backbones and highly catalytic active MoSx nanocrystalline shell on polished commercial glass carbon (GC). In addition, the amounts of MoSx in the hybrids can be easily adjusted, we first demonstrate that small amount of MoSx obviously promotes the HER activity of 2D NbS2 nanoflakes, which is in good consistence with the density functional theory (DFT) calculation results. Meanwhile, the optimized MoSx@NbS2/GC electrocatalyst displays a superior HER activity with an overpotential of -164 mV at -10 mA/cm2, a small Tafel slope of 43.2 mV/dec, and prominent electrochemical stability. This study provides a new path for enhancing the HER performance of 2D TMDC nanoflakes.

A Raman spectroscopy study on the effects of intermolecular hydrogen bonding on water molecules absorbed by borosilicate glass surface

Science.gov (United States)

Li, Fabing; Li, Zhanlong; Wang, Ying; Wang, Shenghan; Wang, Xiaojun; Sun, Chenglin; Men, Zhiwei

2018-05-01

The structural forms of water/deuterated water molecules located on the surface of borosilicate capillaries have been first investigated in this study on the basis of the Raman spectral data obtained at different temperatures and under atmospheric pressure for molecules in bulk and also for molecules absorbed by borosilicate glass surface. The strongest two fundamental bands locating at 3063 cm-1 (2438 cm-1) in the recorded Raman spectra are assigned here to the Osbnd H (Osbnd D) bond stretching vibrations and they are compared with the corresponding bands observed at 3124 cm-1 (2325 cm-1) in the Raman spectrum of ice Ih. Our spectroscopic observations have indicated that the structure of water and deuterated water molecules on borosilicate surface is similar to that of ice Ih (hexagonal phase of ice). These observations have also indicated that water molecules locate on the borosilicate surface so as to construct a bilayer structure and that strong and weak intermolecular hydrogen bonds are formed between water/deuterated molecules and silanol groups on borosilicate surface. In accordance with these findings, water and deuterated water molecules at the interface of capillary have a higher melting temperature.

MoSx-coated NbS2 nanoflakes growth on glass carbon: an advanced electrocatalyst for the hydrogen evolution reaction

KAUST Repository

Zhou, Xiaofeng

2018-01-19

Recent experimental and theoretical studies have demonstrated that two-dimensional (2D) transition metal dichalcogenide (TMDC) nanoflakes are one of the most promising candidates for non-noblemetal electrocatalysts for hydrogen evolution reaction (HER). However, it is still demanding to optimize their conductivity and enrich active sites for the high efficient electrochemical performance. Herein, we report a chemical vapor deposition (CVD) and thermal annealing two-step strategy to controllably synthesize hybrid electrocatalysts consisting of metallic NbS2 nanoflake backbones and highly catalytic active MoSx nanocrystalline shell on polished commercial glass carbon (GC). In addition, the amounts of MoSx in the hybrids can be easily adjusted, we first demonstrate that small amount of MoSx obviously promotes the HER activity of 2D NbS2 nanoflakes, which is in good consistence with the density functional theory (DFT) calculation results. Meanwhile, the optimized MoSx@NbS2/GC electrocatalyst displays a superior HER activity with an overpotential of -164 mV at -10 mA/cm2, a small Tafel slope of 43.2 mV/dec, and prominent electrochemical stability. This study provides a new path for enhancing the HER performance of 2D TMDC nanoflakes.

Liquid hydrogen production and commercial demand in the United States

Science.gov (United States)

Heydorn, Barbara

1990-01-01

Kennedy Space Center, the single largest purchaser of liquid hydrogen (LH2) in the United States, evaluated current and anticipated hydrogen production and consumption in the government and commercial sectors. Specific objectives of the study are as follows: (1) identify LH2 producers in the United States and Canada during 1980-1989 period; (2) compile information in expected changes in LH2 production capabilities over the 1990-2000 period; (3) describe how hydrogen is used in each consuming industry and estimate U.S. LH2 consumption for the chemicals, metals, electronics, fats and oil, and glass industries, and report data on a regional basis; (4) estimate historical and future consumption; and (5) assess the influence of international demands on U.S. plants.

Metastability and thermophysical properties of metallic bulk glass forming alloys

International Nuclear Information System (INIS)

Wunderlich, R.K.; Fecht, H.J.

1998-01-01

The absence of crystallization over a wide time/temperature window can be used to produce bulk metallic glass by relatively slow cooling of the melt. For a number of alloys, including several multicomponent Zr-based alloys, the relevant thermodynamic and thermomechanical properties of the metastable glassy and undercooled liquid states have been measured below and above the glass transition temperature. These measurements include specific heat, viscosity, volume, and elastic properties as a function of temperature. As a result, it becomes obvious that the maximum undercooling for these alloys is given by an isentropic condition before an enthalpic or isochoric instability is reached. Alternatively, these glasses can also be produced by mechanical alloying, thus replacing the thermal disorder by static disorder and resulting in the same thermodynamic glass state. During heating through the undercooled liquid, a nanoscale phase separation occurs for most glasses as a precursor of crystallization

Optical and physical properties of samarium doped lithium diborate glasses

Science.gov (United States)

Hanumantharaju, N.; Sardarpasha, K. R.; Gowda, V. C. Veeranna

2018-05-01

Sm3+ doped lithium di-borate glasses with composition 30Li2O-60B2O3-(10-x) PbO, (where 0 molar volume with samarium ion content indicates the openness of the glass structure. The gradual increase in average separation of boron-boron atoms with VmB clearly indicates deterioration of borate glass network, which in turn leads to decrease in the oxygen packing density. The replacements of Sm2O3 for PbO depolymerise the chain structure and that would increase the concentration of non-bridging oxygens. The marginal increase of optical band gap energy after 1.0 mol.% of Sm2O3 is explained by considering the structural modification in lead-borate. The influence of Sm3+ ion on physical and optical properties in lithium-lead-borate glasses is investigated and the results were discussed in view of the structure of borate glass network.

Development of Self-Luminous Glass Tube (SLGT) Manufacturing Technology

International Nuclear Information System (INIS)

Kim, Kwang Sin; Kim, Kyeong Sook; Chung, Eun Su; Song, Kyu Min; Lee, Sook Kyung; Son, Soon Hwan

2005-01-01

Tritium produced from the Wolsong Tritium Removal Facility (WTRF) will be a radioactive waste when it is stored in the vault inside the WTRF, which requires maintenance cost and is a troublesome waste such that it cannot be sent to the radioactive waste disposal facility. However, when tritium is utilized it can be valuable resource for many applications. As a starting point to utilize tritium we tried to domesticate the selfluminous glass tube (SLGT) manufacturing technology. As a hydrogen isotope, tritium has similar chemical properties to hydrogen but slightly different physical properties. Due to its unstable nature, tritium emits beta rays, which are streams of electrons, with 0∼18.6 keV (5.7 keV in average) energies and 12.323 years of a half-life. The energy level of tritium is relatively low and the biological effects of tritium to the human body are not significant, which makes tritium a popular radioactive isotope for use in industries. The electrons in a beta ray collide with phosphor to produce light so that tritium sealed in phosphor coated glass tubes can make the tubes glow without an external supply of energy. To manufacture these SLGTs, 4 core technologies are needed: coating technology, tritium injection technology, laser sealing/cutting technology and tritium handling technology