Band anticrossing in Group II-Ox-VI1-x highly mismatched alloys: Cd1-yMnyOxTe1-x quaternaries synthesized by O ion implantation (open access)

Band anticrossing in Group II-Ox-VI1-x highly mismatched alloys: Cd1-yMnyOxTe1-x quaternaries synthesized by O ion implantation

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Date: November 5, 2001
Creator: Yu, K. M.; Walukiewicz, W.; Wu, J.; Beeman, J. W.; Ager, J. W., III; Haller, E. E. et al.
Object Type: Article
System: The UNT Digital Library
Constitutive Behavior of Model FCC, BCC, and HCP Metals: Experiments, Modeling and Validation (open access)

Constitutive Behavior of Model FCC, BCC, and HCP Metals: Experiments, Modeling and Validation

The stress-strain responses of a half-hardened copper and an annealed tantalum as a function of temperature and strain-rate were investigated. The rate-dependent yield stress and work-hardening behavior were described satisfactorily by the Mechanical Threshold Strength (MTS) model which is based on thermally-activated plasticity and evolution. Excellent agreement was obtained comparing experiments and calculations of Taylor cylinder impact tests.
Date: January 5, 1999
Creator: Chen, S. R.; Maudlin, P. J. & Gray, G. T., III
Object Type: Article
System: The UNT Digital Library
Dynamic Behavior of Beryllium as a Function of Texture (open access)

Dynamic Behavior of Beryllium as a Function of Texture

The high-strain-rate stress-strain responses of commercial hot-pressed beryllium and rolled-sheet beryllium were studied as a function of orientation in compression and room temperature. Hot-pressed beryllium exhibits isotropic mechanical properties; whereas 16:1 rolled sheet was highly anisotropic. Rolled sheet displayed a factor of two difference in strength between the thickness and in-plane (lowest) directions. Twinning is a key deformation mechanism at high rates.
Date: January 5, 1999
Creator: Blumenthal, W. R.; Abeln, S. P.; Mataya, M. C.; Gray, G. T., III & Cannon, D. D.
Object Type: Article
System: The UNT Digital Library
Robotically Enhanced Advanced Manufacturing Concepts to Optimize Energy, Productivity, and Environmental Performance (open access)

Robotically Enhanced Advanced Manufacturing Concepts to Optimize Energy, Productivity, and Environmental Performance

In the first phase of the REML project, major assets were acquired for a manufacturing line for follow-on installation, capability studies and optimization. That activity has been documented in the DE-FC36-99ID13819 final report. In this the second phase of the REML project, most of the major assets have been installed in a manufacturing line arrangement featuring a green cell, a thermal treatment cell and a finishing cell. Most of the secondary and support assets have been acquired and installed. Assets have been integrated with a commercial, machine-tending gantry robot in the thermal treatment cell and with a low-mass, high-speed gantry robot in the finish cell. Capabilities for masterless gauging of product’s dimensional and form characteristics were advanced. Trial production runs across the entire REML line have been undertaken. Discrete event simulation modeling has aided in line balancing and reduction of flow time. Energy, productivity and cost, and environmental comparisons to baselines have been made. Energy The REML line in its current state of development has been measured to be about 22% (338,000 kVA-hrs) less energy intensive than the baseline conventional low volume line assuming equivalent annual production volume of approximately 51,000 races. The reduction in energy consumption is largely attributable …
Date: November 5, 2007
Creator: Keller, Larry L.; Pack, Joseph M. & Kolarik, Robert V., II
Object Type: Report
System: The UNT Digital Library
Prototype Laser-Activated Shape Memory Polymer Foam Device for Embolic Treatment of Aneurysms (open access)

Prototype Laser-Activated Shape Memory Polymer Foam Device for Embolic Treatment of Aneurysms

None
Date: February 5, 2007
Creator: Maitland, D. J.; Small, W., IV; Ortega, J. M.; Buckley, P. R.; Rodriguez, J.; Hartman, J. et al.
Object Type: Article
System: The UNT Digital Library
Data Summary Report for the 1997 Semiannual Tritium Survey for Fourmile Branch and the F- and H-Area Seeplines (open access)

Data Summary Report for the 1997 Semiannual Tritium Survey for Fourmile Branch and the F- and H-Area Seeplines

This report presents a summary of the definitive data validation and verification for the 1997 RFI/RI semiannual tritium survey for Fourmile Branch and the F- and H-Area Seeplines. The RFI/RI was performed under the direction of WSRC ESS/Ecology. This report was prepared under the direction EPD/EMS.
Date: January 5, 1998
Creator: Koch, J. W., II
Object Type: Report
System: The UNT Digital Library
The excitation function for /sup 48/V from tritons on natural titanium (open access)

The excitation function for /sup 48/V from tritons on natural titanium

Natural titanium is used as a diagnostic charged particle detector in nuclear device tests making use of the proton and deuteron reactions, which produce vanadium 48 as a product. The presence of tritons in the reaction environment can also produce vanadium 48 from triton reactions on titanium 3, titanium 47 and titanium 48. Triton reaction cross sections for titanium have been measured so that corrections to the proton and deuteron diagnostic data can be accurately calculated. These measurements were made using the Van de Graaff at the Los Alamos National Laboratory.
Date: May 5, 1987
Creator: West, H. I., Jr.; Lanier, R.G.; Mustafa, M.G. & O'Brien, H.
Object Type: Report
System: The UNT Digital Library
Dimensional Measurements of Three Tubes by Computed Tomography (open access)

Dimensional Measurements of Three Tubes by Computed Tomography

Low density polyethylene (LDPE), copper (Cu), and gold (Au) tubes were scanned on KCAT to identify and evaluate the impact of phase effects on quantitative object recovery. These tubes are phantoms for high energy density capsules.[Logan, et al. 2004] Digital radiographs for each tube are shown in Figure 1. The LDPE tube was scanned at 60 kV, while the Cu and the Au tubes were scanned at 140 kV. All tubes were scanned at a magnification of 3, with approximately 100-mm distance between the exit plane of the tube and the scintillator. Notice the prominence of the outer bright and inner dark edges for the LDPE tube DR, and their absence from the Cu and Au tube DRs. The bright and dark edges are a result of change in phase of the x-rays. The x-ray fluence is partly attenuated and partly refracted. The location near the outer edge of the tube appears to be more attenuating since those x-rays have refracted to locations just outside the tube. Alternatively, the added counts from the refraction result in intensities that are greater than the incident intensity effectively representing a ''negative attenuation''. This results in more counts in that location than in the …
Date: October 5, 2004
Creator: Schneberk, D. J.; Martz, H. E., Jr. & Brown, W. D.
Object Type: Report
System: The UNT Digital Library
Direct catalytic conversion of methane and light hydrocarbon gases. Quarterly report No. 5, November 16, 1987--January 15, 1988 (open access)

Direct catalytic conversion of methane and light hydrocarbon gases. Quarterly report No. 5, November 16, 1987--January 15, 1988

The goal of this research is to develop catalysts that directly convert methane and light hydrocarbons to intermediates that later can be converted to either liquid fuels or value-added chemicals, as economics dictate. During this reporting period, we have synthesized and tested several novel catalysts for methane reforming (Tasks 1 and 2) and for partial oxidation of methane (Tasks 3 and 4). We started to test a mixed metal system, an FeRu{sub 3} cluster. This catalyst was supported both on zeolite and on magnesium oxide and the systems were tested for methane reforming at various reaction temperatures. We also prepared and tested a monomeric ruthenium catalyst supported on magnesium oxide. We found that methane is activated at a lower temperature with the basic magnesium oxide support than with acidic supports such as zeolite or alumina. Methane conversions increased with temperature, but the production of coke also increased. We prepared a sterically hindered ruthenium porphyrin encapsulated in a zeolite supercage for catalysis of methane oxidation. The results showed that only carbon dioxide was produced. Addition of axial base to this catalyst gave similar results. Another type of catalyst, cobalt Schiff base complexes, was also prepared and tested for methane oxidation. In …
Date: February 5, 1988
Creator: Wilson, R. B., Jr. & Wai, Chan Yee
Object Type: Report
System: The UNT Digital Library
Marginal Stability Diagrams for Infinite-n Ballooning Modes in Quasi-symmetric Stellarators (open access)

Marginal Stability Diagrams for Infinite-n Ballooning Modes in Quasi-symmetric Stellarators

By perturbing the pressure and rotational-transform profiles at a selected surface in a given equilibrium, and by inducing a coordinate variation such that the perturbed state is in equilibrium, a family of magnetohydrodynamic equilibria local to the surface and parameterized by the pressure gradient and shear is constructed for arbitrary stellarator geometry. The geometry of the surface is not changed. The perturbed equilibria are analyzed for infinite-n ballooning stability and marginal stability diagrams are constructed that are analogous to the (s; alpha) diagrams constructed for axi-symmetric configurations. The method describes how pressure and rotational-transform gradients influence the local shear, which in turn influences the ballooning stability. Stability diagrams for the quasi-axially-symmetric NCSX (National Compact Stellarator Experiment), a quasi-poloidally-symmetric configuration and the quasi-helically-symmetric HSX (Helically Symmetric Experiment) are presented. Regions of second-stability are observed in both NCSX and the quasi-poloidal configuration, whereas no second stable region is observed for the quasi-helically symmetric device. To explain the different regions of stability, the curvature and local shear of the quasi-poloidal configuration are analyzed. The results are seemingly consistent with the simple explanation: ballooning instability results when the local shear is small in regions of bad curvature. Examples will be given that show that …
Date: December 5, 2003
Creator: Hudson, S. R.; Hegna, C. C.; Torasso, R. & Ware, A.
Object Type: Report
System: The UNT Digital Library
Tennessee Valley Authority Eagle Bend 161-kV delivery point environmental assessment (open access)

Tennessee Valley Authority Eagle Bend 161-kV delivery point environmental assessment

Eagle Bend is an area located in a bend of the Clinch River about one mile southeast of Clinton, Tennessee, in Anderson County. This area, including an industrial park, is supplied electric power by the Clinton Utilities Board (UB) through its 69-kV system, which is in turn supplied by TVA over a 69-kV transmission line from Norris Hydro Plant. Studies of the power supply in the area indicate that there will likely be significant load growth both in the Clinton area in general and the industrial park in particular. Studies further show that if this new load is supplied at 69-kV, the TVA transformer at Norris Hydro which supplies this load will be overloaded by the summer of 1993 and no feasible alternate source which would maintain the quality and reliability of the power delivered to the Clinton system exists to accept this load. Clinton UB also needs to transfer load from its Clinton substation in the same time period to prevent overloading. Additional studies and consultation between TVA and Clinton UB have indicated that the best solution to this problem is to supply this load at 161-kV at a new delivery point for Clinton UB. This would require the …
Date: February 5, 1993
Creator: unknown
Object Type: Report
System: The UNT Digital Library