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Preliminary study of the recycling of spent gases from the iodine laser

Description: A process is proposed for recycling the spent gases from the iodine laser. Using a simplified form of this process, a preliminary estimate of the energy cost to recycle the perfluoroisopropyliodide-argon gas mixture used as the laser medium in the iodine laser was made. If r is defined as the ratio of the recycling energy to the output energy of the laser, a figure of 70 is arrived at for the most optimistic conditions and 160 for the most probable conditions. A major portion of the energy necessary for recycling is consumed in the synthesis of the perfluoroiodide compound. An estimate of the cost to replace the lost perfluoroiodide, if purchased, is from $2.4 to 10 million per year, based on a continuous operation at the 100-kJ laser power level.
Date: September 10, 1976
Creator: Pearson, R. K. (ed.)
Partner: UNT Libraries Government Documents Department

Revisiting the S-Au(111) interaction: Static or Dynamic?

Description: The chemical inertness typically observed for Au does not imply a general inability to form stable bonds with non-metals but is rather a consequence of high reaction barriers. The Au-S interaction is probably the most intensively studied interaction of Au surfaces with non-metals as, for example, it plays an important role in Au ore formation, and controls the structure and dynamics of thiol-based self-assembled-monolayers (SAMs). In recent years a quite complex picture of the interaction of sulfur with Au(111) surfaces emerged, and a variety of S-induced surface structures was reported under different conditions. The majority of these structures were interpreted in terms of a static Au surface, where the positions of the Au atoms remain essentially unperturbed. Here we demonstrate that the Au(111) surface exhibits a very dynamic character upon interaction with adsorbed sulfur: low sulfur coverages modify the surface stress of the Au surface leading to lateral expansion of the surface layer; large-scale surface restructuring and incorporation of Au atoms into a growing two-dimensional AuS phase were observed with increasing sulfur coverage. These results provide new insight into the Au-S surface chemistry, and reveal the dynamic character of the Au(111) surface.
Date: August 17, 2004
Creator: Biener, M M; Biener, J & Friend, C M
Partner: UNT Libraries Government Documents Department

Dependence of strength on particle size in graphite

Description: The strength to particle size relationship for specially fabricated graphites has been demonstrated and rationalized using fracture mechanics. In the past, similar studies have yielded empirical data using only commercially available material. Thus, experimental verification of these relationships has been difficult. However, the graphites of this study were fabricated by controlling the particle size ranges for a series of isotropic graphites. All graphites that were evaluated had a constant 1.85 g/cm/sup 3/ density. Thus, particle size was the only variable. This study also considered the particle size effect on other physical properties; coefficient of thermal expansion (CTE), electrical resistivity, fracture strain, and Young's modulus.
Date: June 8, 1980
Creator: Kennedy, E.P. & Kennedy, C.R.
Partner: UNT Libraries Government Documents Department

Comparative analysis of hydrogen fire and explosion incidents. Quarterly report No. 1, September 1, 1977--November 30, 1977

Description: A hydrogen accident data base covering industrial and other forms of hydrogen use is being developed. Ten different sources of hydrogen accident reports have contributed 168 reports for the period 1971-1976 and 402 reports for the years prior to 1971. Additional data are being sought through a survey of major hydrogen consuming industries. National gas consumption and accident data have also been collected to serve as a basis for comparison with the hydrogen accident data. During the next quarter, a computer data entry and retrieval program will be written to sort and tabulate the hydrogen accident data.
Date: December 1, 1977
Creator: Zalosh, R.G.
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

Carbon in high-purity germanium

Description: Using /sup 14/C-spiked pyrolytic graphite-coated quartz crucibles for the growth of nine ultra-pure germanium single crystals, we have determined the carbon content and distribution in these crystals. Using autoradiography, we observe a rapidly decreasing carbon cluster concentration in successively grown crystals. Nuclear radiation detectors made from the crystals measure the betas from the internally decaying /sup 14/C nuclei with close to 100% efficiency. An average value for the total carbon concentration (/sup 14/C + /sup 12/C) is approx. 2 x 10/sup 14/ cm/sup -3/, a value substantially larger than expected from earlier metallurgical studies. Contrary to the most recent measurement, we find the shape of the beta spectrum to agree very well with the statistical shape predicted for allowed transitions.
Date: October 1, 1981
Creator: Haller, E.E.; Hansen, W.L.; Luke, P.; McMurray, R. & Jarrett, B.
Partner: UNT Libraries Government Documents Department

Membrane oxygen enrichment cost and application evaluation

Description: A separation process, similar to the reverse osmosis membrane process for the desalination of water, can be used for the separation and enrichment of multi-component gas streams. The development of new processing methods and modular packing systems together with advanced commercialization of desalination systems now makes similar processes for gas separation appear feasible and economical. Composite membranes have been developed that are both thin enough to provide a large gas flow and strong enough to withstand the driving pressure of the incoming gas. This is done by depositing a polymer on the finely porous surface of a fabric-reinforced supporting membrane. The resulting material is then formed into a spiral-wound element that provides a large amount of membrane area in a small volume. Laboratory experiments using gas separation membranes by Fluid Systems Division of UOP and by General Electric Company have established the technical feasibility of using such membranes to produce oxygen-enriched air. A preliminary analysis of membrane oxygen enrichment economics was prepared by the Fluid System Division of UOP which shows that oxygen enrichment could be profitable for combustion systems up to 100 tons of oxygen per day. A supporting economic study made by Econergy Associates reaffirms the positive economics potential for a 1000-ton/d, 30% O/sub 2/ enrichment plant.
Date: March 1, 1979
Creator: Fischer, J. & Burnett, L.J.
Partner: UNT Libraries Government Documents Department

Description of a unique machine tool permitting achievement of < 15-A rms diamond-turned surfaces

Description: A new machine tool now in the final stages of development at the Pacific Northwest Laboratory uses a unique tool motion to produce diamond-turned surfaces of exceptionally high quality. The cutting tool is programmed to move in 4-nm increments along two axes: an X axis and an Omega axis. Exceptionally stiff and accurate control of the tool is possible with this Omega-X system. Copper surfaces of revolution have been produced with a 12.3-A rms surface finish and a contour accuracy of 75 nm. In conjunction with a unique, thermally stabilized air bearing spindle and machine calibration equipment, the Omega-X system permits a significant advance in the fabrication of optical-quality surfaces for use with the visible spectrum.
Date: January 1, 1980
Creator: Miller, D.M.; Hauver, G.H.; Culverhouse, J.N. & Greenwell, E.N.
Partner: UNT Libraries Government Documents Department

Optical measurements on hydrogen at ultrahigh static pressures. Summary report for NRIP W233

Description: The results of a two-year New Research Initiatives Program (NRIP) aimed at developing apparatus and techniques for studying hydrogen and other gases under ultrahigh static pressure in diamond--anvil cells are summarized. The following goals were achieved: A facility was established in which precision optical measurements can be made; special diamond cells for use at low temperatures were built; procedures were devised for loading cells with gases at high density; preliminary visual, x-ray, and spectral studies on various gases at pressures up to 50 kbar were conducted; and having demonstrated the feasibility of NRIP, other sponsorship on a continuing basis was obtained.
Date: February 1, 1979
Creator: Mills, R.L. & Liebenberg, D.H.
Partner: UNT Libraries Government Documents Department

Low earth orbit molecular beam space simulation facility

Description: A brief synopsis of the low earth orbit (LEO) satellite environment is presented including neutral and ionic species. Two ground based atomic and molecular beam instruments are described which are capable of simulating the interaction of space craft surfaces with the LEO environment and detecting the results of these interactions. The first detects mass spectrometrically low level fluxes of reactively and nonreactively surface scattered species as a function of scattering angle and velocity while the second UHV molecular beam, laser induced fluorescence apparatus is capable of measuring chemiluminescence produced by either gas phase or gas-surface interactions. A number of proposed experiments will be described.
Date: January 1, 1984
Creator: Cross, J.B.
Partner: UNT Libraries Government Documents Department

Safety aspects of large-scale handling of hydrogen

Description: Since the decade of the 1950s, there has been a large increase in the quantity of hydrogen, especially liquid hydrogen, that has been produced, transported, and used. The technology of hydrogen, as it relates to safety, has also developed at the same time. The possible sources of hazards that can arise in the large-scale handling of hydrogen are recognized, and for the most part, sufficiently understood. These hazard sources are briefly discussed. 26 refs., 4 figs.
Date: January 1, 1988
Creator: Edeskuty, F. J. & Stewart, W. F.
Partner: UNT Libraries Government Documents Department

The new experimental areas oxygen monitor

Description: Because of the nature of the beamline requirements for oxygen monitoring equipment to operate ancillary equipment, such as exhaust fans, doors and cryogenic valves, and because of the well known problems of the oxygen sensors installed in high radiation areas, a new design for sensing the oxygen content of ambient air was needed. A new monitor system was designed to solve these problems and some others that compromised the reliability and the maintenance of the monitoring system. From the operating experience gained with the Accelerator Standard Oxygen Monitor System currently installed in many locations in the experimental area, from suggestions solicited from the Safety Group and from the Cryogenics Group, I designed a new Experimental Areas Standard Oxygen Monitor. Many suggestions were carefully considered and a design that incorporates most of them was constructed. I will summarize a list of the important improvements that will be of interest to the users of the system, and explain how these functions will make the oxygen system easier to live with. 2 figs.
Date: August 1, 1988
Creator: Schoo, D.
Partner: UNT Libraries Government Documents Department

Recommendation of a triaxial failure theory for graphite

Description: An extensive literature search has been conducted on the application of triaxial failure theories to an anisotropic brittle solid. This study leads to the conclusion that the strength tensor theory of Tsai and Wu appears most promising for HTGR structural graphites. The reduction of this theory to model the transversely isotropic nature of HTGR structural graphites is presented. The extensions to the ongoing biaxial stress experimental program, needed to provide the additional data required to verify this theory, are defined.
Date: May 1, 1979
Creator: Tang, P.Y.
Partner: UNT Libraries Government Documents Department

Modified Weibull theory and stress-concentration factors of polycrystalline graphite

Description: Stress concentration factors (SCF) due to geometric discontinuities in graphite specimens are observed to be much less than the theoretical SCF in an elastic material. In fact, the experimental SCF is always less than two and sometimes even less than one. A four parameter Weibull theory which recognizes the grain size effect is found to give an adequate explanation of the above observed discrepancies.
Date: December 1, 1980
Creator: Ho, F.H.
Partner: UNT Libraries Government Documents Department

Fracture toughness of anisotropic graphites

Description: Fracture toughness measurements have been made at 0, 30, 45, 60, and 90/sup 0/ from the extrusion axis on a reasonably anisotropic graphite, grade AGOT. It was found that the fracture toughness did not vary appreciably with orientation. An observed variation in strength was found to be the result of defect orientation.
Date: January 1, 1985
Creator: Kennedy, C.R. & Kehne, M.T.
Partner: UNT Libraries Government Documents Department