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Development of the Hybrid Sulfur Thermochemical Cycle

Description: The production of hydrogen via the thermochemical splitting of water is being considered as a primary means for utilizing the heat from advanced nuclear reactors to provide fuel for a hydrogen economy. The Hybrid Sulfur (HyS) Process is one of the baseline candidates identified by the U.S. Department of Energy [1] for this purpose. The HyS Process is a two-step hybrid thermochemical cycle that only involves sulfur, oxygen and hydrogen compounds. Recent work has resulted in an improved process design with a calculated overall thermal efficiency (nuclear heat to hydrogen, higher heating value basis) approaching 50%. Economic analyses indicate that a nuclear hydrogen plant employing the HyS Process in conjunction with an advanced gas-cooled nuclear reactor system can produce hydrogen at competitive prices. Experimental work has begun on the sulfur dioxide depolarized electrolyzer, the major developmental component in the cycle. Proof-of-concept tests have established proton-exchange-membrane cells (a state-of-the-art technology) as a viable approach for conducting this reaction. This is expected to lead to more efficient and economical cell designs than were previously available. Considerable development and scale-up issues remain to be resolved, but the development of a viable commercial-scale HyS Process should be feasible in time to meet the commercialization schedule for Generation IV gas-cooled nuclear reactors.
Date: September 23, 2005
Creator: Summers, William A. & Steimke, John L
Partner: UNT Libraries Government Documents Department

Isotopic HCl transfer laser

Description: An HCl laser which uses isotopic V-V energy transfer collisions as a pumping mechanism has been demonstrated. This multiline laser, which utilized an intracavity cold gas isotope filter, increased the energy from the P/sub 1/ lines of H/sup 37/Cl while decreasng the energies of the P/sub 1/ and P/sub 2/ lines of H/sup 35/Cl. Previously unreported lines, including emission from R branch transitions, have also been observed from single-line HCl and HBr lasers.
Date: December 15, 1977
Creator: Badcock, C.C.; Hwang, W.C.; Kalsch, J.F. & Kamada, R.F.
Partner: UNT Libraries Government Documents Department

Investigation into the high strain-rate behavior of compacted sand using the split-Hopkinson pressure bar technique

Description: The results of compressive high strain-rate experiments on compacted sand are presented. Experiments were conducted on a 60.3 mm split Hopkinson pressure bar (SHPB). The experiments showed that the assumptions necessary for a valid SHPB experiment are satisfied when using compacted sand samples constrained to a nearly uniaxial strain state. Results show that the sample stress-strain response is governed principally by the initial sample gas porosity, and that no strain-rate dependence is exhibited at sample strains less than the initial gas porosity. Several stress-strain curves are presented for samples prepared at several combinations of moisture content and density with applied stresses and strain rates up to 520 MPa and 4000 sec/sup -1/, respectively.
Date: January 1, 1985
Creator: Felice, C.W.; Brown, J.A.; Gaffney, E.S. & Olsen, J.M.
Partner: UNT Libraries Government Documents Department

Experimental Determination of Phase Equilibria in the System H{sub 2}O-CO{sub 2}-NaCl at 0.5 Kb from 500 to 800C

Description: An understanding of activity-composition (a/X) relations and phase equilibria for halite-bearing, mixed-species supercritical fluids is critically important to many geological and industrial applications. The authors have performed experiments on the phase equilibria of H{sub 2}O-CO{sub 2}-NaCl fluids from 500 C to 800 C at 500 bars, conditions of significant importance in studies of magma-hydrothermal systems, geothermal reservoirs and some ore deposits, to obtain highly accurate and precise data for this ternary system. These experiments are conducted using a double capsule technique. An excess of NaCl is placed in an inner Pt capsule, which is crimped shut and placed in an outer capsule containing H{sub 2}O and CO{sub 2}. During the experiment NaCl dissolves out of the inner capsule, and is deposited in the outer capsule during the quench. After the experiment the capsule is opened, and the amount of NaCl remaining in the inner capsule determined by dissolution. The difference between the initial and final amounts of NaCl in the inner capsule yields the solubility of NaCl at the P-T conditions of the experiment. At 500 C data from these experiments suggest that the vapor comer of the three-phase field lies near X(H{sub 2}O) = 0.760, X(NaCl) = 0.065, which is a significantly more water-rich composition than suggested by previous models. As expected, increasing temperature increases the solubility of NaCl in the NaCl-vapor field. For example, at intermediate H{sub 2}O/CO{sub 2} ratios the vapor field extends from approximately near X(H{sub 2}O) = 0.66, X(NaCl) = 0.06 at 500 C to near X(H{sub 2}O) = 0.65, X(NaCl) = 0.08 at 600 C.
Date: January 9, 2001
Creator: Anovitz, L.M.
Partner: UNT Libraries Government Documents Department

Multistage metal hydride compressor

Description: Metal hydride compressors can compress hydrogen to high pressures without using mechanical moving parts. They are particularly suited for tritium applications because they require minimal maintenance. A three-stage metal hydride compressor which can compress hydrogen from 14.7 to 20,000 psia has been demonstrated. The design principle and experimental results are presented.
Date: January 1, 1986
Creator: Heung, L.K.
Partner: UNT Libraries Government Documents Department

Deburring: technical capabilities and cost-effective approaches, Lessons 9 and 10

Description: Abrasive jet, water jet, and abrasive flow deburring are not panaceas for the world's deburring problems. They do, however, solve many of the problems where burrs are either difficult to reach or amenable to automation. As seen in this lesson, they can deburr miniature parts as well as large parts. In almost every case; however, one will note that accessibility of the burr is the key to the success of these processes. Volumes have been published on the effects of abrasive jet parameters. The reader is encouraged to pursue some of the citations in the Source of Additional Information for further quantitative information. Similarly, data on abrasive flow deburring is also available. Little data, however, has been published on water jet deburring.
Date: June 1, 1980
Creator: Gillespie, L.K.
Partner: UNT Libraries Government Documents Department

Production of hydrogen bromide by bromine-methane reactions at elevated temperature.

Description: Hydrogen bromide is a potentially useful intermediate for hydrogen production by electrolysis because it has a low cell potential and is extremely soluble in water. Processes have been proposed to exploit these properties, but among the important issues to be resolved is the efficiency of HBr production from hydrocarbon precursors. This investigation evaluated a fundamental facet of such a technology by studying the reaction of methane and bromine at elevated temperature to determine the yield and kinetics of HBr formation. Laboratory experimentation and computational chemistry were combined to provide a description of this reaction for possible application to reactor design at a larger scale. Experimental studies with a tubular flow reactor were used to survey a range of reactant ratios and reactor residence times at temperatures between 500 C and 800 C. At temperatures near 800 C with excess methane, conversions of bromine to HBr exceeded 90% and reaction products included solid carbon (soot) in stoichiometric amounts. At lower temperatures, HBr conversion was significantly reduced, the products included much less soot, and the formation of bromocarbon compounds was indicated qualitatively. Calculations of chemical equilibrium behavior and reaction kinetics for the experimental conditions were performed using the Sandia CHEMKIN package. An elementary multistep mechanism for the gas-phase chemistry was used together with a surface mechanism that assumed facile deposition of radical species at the reactor walls. Simulations with the laminar-flow boundary-layer code of the CHEMKIN package gave reasonable agreement with experimental data.
Date: May 1, 2003
Creator: Bradshaw, Robert W. & Larson, Richard S.
Partner: UNT Libraries Government Documents Department

SPE water electrolysis technology development for large scale hydrogen production. Progress report No. 6, January 1, 1977--March 31, 1977

Description: The status of the following studies is reported: low cost current collector development, high temperature operation, catalytic electrode development, low cost polymer development, evaluation of the effect of hydrogen enrichment on older gas pipelines, cell and SPE optimization, cell assembly design, stack assembly design, manufacturing process development, and system analysis and definition.
Date: April 25, 1977
Partner: UNT Libraries Government Documents Department

Characterization of titanium metal powder by pulsed NMR

Description: Moisture absorption as a function of surface area in titanium metal powders was studied by pulsed NMR. Wet samples were air-dried for 16 days under normal laboratory conditions (20 to 22/sup 0/C, 40 to 60 percent relative humidity) and the moisture contents were compared with those of vacuum-dried (200/sup 0/C, 1.33 mPa) samples and vacuum-dried samples exposed to 50 percent relative humidity. For one sample, the drying efficiency of 100/sup 0/C as compared to 200/sup 0/C, as well as the moisture absorption capacity as a function of time, was also studied. The moisture, hydride hydrogen (TiH/sub 2/), and oxygen contents of titanium metal powders were found to be functions of surface area. Moisture absorbed was a linear function and hydrogen and oxygen were exponential functions of surface area. Titanium metal powder absorbs an equilibrium value of moisture (approximately 0.60 wt percent) within one hour of exposure to 50 percent relative humidity. The drying of titanium metal powder was found to be as effective at 100/sup 0/C as at 200/sup 0/C.
Date: January 1, 1977
Creator: Attalla, A.
Partner: UNT Libraries Government Documents Department

Filament preheating for phi targets

Description: The vaporization and preheating of a CD/sub 2/ filament inside a target is examined to investigate operation of such a target. The experimental arrangement duplicated the previous shots, with prepulse levels of 40 to 120 kV and several kA, and use of identical phi targets with CD/sub 2/ filaments. The behavior of the filament was observed by optical methods and was seen to consist of luminous and plasma phases in turn. This behavior is consistent with earlier hypotheses concerning phi target operation.
Date: February 1, 1979
Creator: Olsen, J.N.
Partner: UNT Libraries Government Documents Department

Lines in the spectrum of /sup 7/LiH (5177 to 8643 A)

Description: The emission spectra of the A /sup 1/..sigma../sup +/ - X /sup 1/..sigma../sup +/ bands of /sup 7/LiH were photographed in the 5177 A to 8643 A region in the fourth, fifth, and sixth order of a 3.4 meter Ebert Spectrograph with reciprocal dispersions of 2.2, 1.7, and 1.4 A/mm. The measured lines in the spectra of /sup 7/LiH in the region 5177 to 8643 A are given. Similar spectra for the region 4728 to 5298 A are given in the companion report (COO-2326-19). In the small region of overlap (5177 to 5298 A), the line positions are in good agreement, but these are felt to be the more accurate.
Date: January 1, 1979
Creator: Orth, F.B. & Stwalley, W.C.
Partner: UNT Libraries Government Documents Department

Microstructure of amorphous-silicon-based solar cell materials by small-angle x-ray scattering. Annual technical report, April 6, 1995--April 5, 1996

Description: The objective of this project is to provide detailed microstructural information on the amorphous silicon based thin film materials under development for improved multijunction solar cells. Correlation of microstructure with opto-electrical properties and device performance is an integral part of the research. During this second phase of our three-year program we have obtained information on the microstructure of materials relevant to the Low-, Mid-, and High-bandgap Teams and the results are appropriately divided into these three types of material as presented below. The experimental methods, data analysis, and interpretation procedures are the same as those described in detail in the phase-one report and in the review paper published last year.
Date: August 1, 1996
Creator: Williamson, D.L.
Partner: UNT Libraries Government Documents Department

General Chemistry Technical Note No. 71: Hydrogen compounds of low atomic weight

Description: This report provides a compilation of Hydrogen compounds of low atomic weight. Compounds known and reported in literature are given. Cations and anions of high Hydrogen content and/or low Z are provided as are molecules which form Lewis salts. Finally, unknown compounds for which synthesis seems probable are given.
Date: March 30, 1962
Creator: Pearson, R. K.
Partner: UNT Libraries Government Documents Department

Transverse stimulated Raman scattering in KDP

Description: Optical components of large-aperture, high irradiance and high fluence lasers can experience significant levels of stimulated scattering along their transverse dimensions. The authors have observed transverse stimulated Raman scattering in large aperture KDP crystals, and have measured the stimulated gain coefficient. With sufficiently high gain, transverse stimulated scattering can lead to energy loss from the main beam and, more importantly, optical damage in the components in which this scattering occurs. Thus transverse stimulated,scattering is of concern in large aperture fusion lasers such as Nova and Beamlet, which is a single-aperture, full-scale scientific prototype of the laser driver for the proposed National Ignition Facility.
Date: September 12, 1995
Creator: Barker, C.E.; Sacks, R.A.; Wonterghem, B.M. Van; Caird, J.A.; Murray, J.R.; Campbell, J.H. et al.
Partner: UNT Libraries Government Documents Department

Water vapor pressure gauge

Description: An inexpensive pressure gauge, able to measure the N/sub 2/ and H/sub 2/O components within a vacuum system in the pressure range 1..mu.. to 400..mu.. is described and results of tests of the device are reported.
Date: January 1, 1980
Creator: Edwards, D Jr & Gillette, D
Partner: UNT Libraries Government Documents Department

Subsurface flow and transport of organic chemicals: an assessment of current modeling capability and priority directions for future research (1987-1995)

Description: Theoretical and computer modeling capability for assessing the subsurface movement and fate of organic contaminants in groundwater was examined. Hence, this study is particularly concerned with energy-related, organic compounds that could enter a subsurface environment and move as components of a liquid phase separate from groundwater. The migration of organic chemicals that exist in an aqueous dissolved state is certainly a part of this more general scenario. However, modeling of the transport of chemicals in aqueous solution has already been the subject of several reviews. Hence, this study emphasizes the multiphase scenario. This study was initiated to focus on the important physicochemical processes that control the behavior of organic substances in groundwater systems, to evaluate the theory describing these processes, and to search for and evaluate computer codes that implement models that correctly conceptualize the problem situation. This study is not a code inventory, and no effort was made to identify every available code capable of representing a particular process.
Date: September 1, 1986
Creator: Streile, G.P. & Simmons, C.S.
Partner: UNT Libraries Government Documents Department