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APPLICATIONS OF IR THERMOGRAPHY IN CAPTURING THERMAL TRANSIENTS AND OTHER HIGH SPEED THERMAL EVENT (open access)

APPLICATIONS OF IR THERMOGRAPHY IN CAPTURING THERMAL TRANSIENTS AND OTHER HIGH SPEED THERMAL EVENT

The high-speed, snap-shot mode, and the external triggering capability of an IR camera allows thermal transients to be captured. These advanced features were used to capture thermal transients during electrical breakdown of ZnO varistors and to freeze the rotation of an automobile disk brake in order to study thermoplastic instability in the braking system. The IR camera also showed the thermoplastic effect during cyclic fatigue testing of a glass matrix composite.
Date: June 7, 1999
Creator: Wang, H.; Dinwiddie, R. B. & Graham, S.
System: The UNT Digital Library
Approximate Identification of Boundary Properties in a Wave Equation by Optimal Control Techniques (open access)

Approximate Identification of Boundary Properties in a Wave Equation by Optimal Control Techniques

We apply optimal control techniques to find approximate solutions to an inverse problem for the acoustic wave equation. The inverse problem is to determine the shape and reflection coefficient of a part of the boundary from partial measurements of the acoustic signal. The sought functions are treated as controls and the goal is to drive the model solution close to the experimental data by adjusting these functions.
Date: June 7, 1999
Creator: Lenhart, S.; Protopopescu, V. & Yong, J.
System: The UNT Digital Library
Atlas Pulsed Power Facility for High Energy Density Physics Experiments (open access)

Atlas Pulsed Power Facility for High Energy Density Physics Experiments

The Atlas facility, now under construction at Los Alamos National Laboratory (LANL), will provide a unique capability for performing high-energy-density experiments in support of weapon-physics and basic-research programs. It is intended to be an international user facility, providing opportunities for researchers from national laboratories and academic institutions around the world. Emphasizing institutions around the world. Emphasizing hydrodynamic experiments, Atlas will provide the capability for achieving steady shock pressures exceeding 10-Mbar in a volume of several cubic centimeters. In addition, the kinetic energy associated with solid liner implosion velocities exceeding 12 km/s is sufficient to drive dense, hydrodynamic targets into the ionized regime, permitting the study of complex issues associated with strongly-coupled plasmas. The primary element of Atlas is a 23-MJ capacitor bank, comprised of 96 separate Marx generators housed in 12 separate oil-filled tanks, surrounding a central target chamber. Each tank will house two, independently-removable maintenance units, with each maintenance unit consisting of four Marx modules. Each Marx module has four capacitors that can each be charged to a maximum of 60 kilovolts. When railgap switches are triggered, the marx modules erect to a maximum of 240 kV. The parallel discharge of these 96 Marx modules will deliver a 30-MA …
Date: June 7, 1999
Creator: Miller, R. B.; Ballard, E. O.; Barr, G. W.; Bowman, D. W.; Chochrane, J. C.; Davis, H. A. et al.
System: The UNT Digital Library
Efficient powder blending in support of plutonium conversion for mixed oxide fuel (open access)

Efficient powder blending in support of plutonium conversion for mixed oxide fuel

This paper describes a unique system that is used to mix and blend multiple batches of plutonium oxide powder of various consistencies into an equivalent number of identical and homogeneously mixed batches. This system is being designed and built to support the Advanced Recovery and Integrated Extraction System (ARIES) at the Los Alamos TA-55 Plutonium Facility. The ARIES program demonstrates dismantlement of nuclear pits, retrieval of the plutonium components, and conversion of the plutonium into an oxide for eventual use in mixed oxide (MOX) fuel for nuclear reactors. The purpose of this powder blending work is to assure that ARIES oxide is converted into an unclassified homogeneous mixture and that consistent feed material is available for MOX fuel assembly. This blending system is being assembled in a selected glovebox a TA-55 using an LANL designed split/combine apparatus, a commercial Turbula blending unit, and several additional supporting hardware components.
Date: June 7, 1999
Creator: Dennison, D.K.; Brucker, J.P. & Martinez, H.E.
System: The UNT Digital Library
Exposure of Ceramics and Ceramic Matrix Composites in Simulated and Actual Combustor Environments (open access)

Exposure of Ceramics and Ceramic Matrix Composites in Simulated and Actual Combustor Environments

A high-temperature, high-pressure, tube furnace has been used to evaluate the long term stability of different monolithic ceramic and ceramic matrix composite materials in a simulated combustor environment. All of the tests have been run at 150 psia, 1204 degrees C, and 15% steam in incremental 500 h runs. The major advantage of this system is the high sample throughput; >20 samples can be exposed in each tube at the same time under similar exposure conditions. Microstructural evaluations of the samples were conducted after each 500 h exposure to characterize the extent of surface damage, to calculate surface recession rates, and to determine degradation mechanisms for the different materials. The validity of this exposure rig for simulating real combustor environments was established by comparing materials exposed in the test rig and combustor liner materials exposed for similar times in an actual gas turbine combustor under commercial operating conditions.
Date: June 7, 1999
Creator: Brentnall, William D.; Ferber, Mattison K.; Keiser, James R.; Miriyala, Narendernath; More, Karren L.; Price, Jeffrey R. et al.
System: The UNT Digital Library
Fuel-flexible partial oxidation reforming of hydrocarbons for automotive applications. (open access)

Fuel-flexible partial oxidation reforming of hydrocarbons for automotive applications.

Micro-reactor tests indicate that our partial oxidation catalyst is fuel-flexible and can reform conventional (gasoline and diesel) and alternative (ethanol, methanol, natural gas) fuels to hydrogen rich product gases with high hydrogen selectivity. Alcohols are reformed at lower temperatures (< 600 C) while alkanes and unsaturated hydrocarbons require slightly higher temperatures. Cyclic hydrocarbons and aromatics have also been reformed at relatively low temperatures, however, a different mechanism appears to be responsible for their reforming. Complex fuels like gasoline and diesel, which are mixtures of a broad range of hydrocarbons, require temperatures of > 700 C for maximum hydrogen production.
Date: June 7, 1999
Creator: Ahmed, S.; Carter, J. D.; Kopasz, J. P.; Krumpelt, M. & Wilkenhoener, R.
System: The UNT Digital Library
Mass-Transport-Limited Electrodeposition of High-Surface-Area Coatings for Surface Acoustic Wave Sensor Technology (open access)

Mass-Transport-Limited Electrodeposition of High-Surface-Area Coatings for Surface Acoustic Wave Sensor Technology

The sensitivity of surface acoustic wave (SAW) sensors has been enhanced by increasing the active surface area of these devices, Electrodepositions of Ni, Pd, and Pt in a mass-transport-limited mode with trace foreign metals yield highly dendritic crystal structures of uniform macroscopic thickness. The concentration of metal ions, supporting electrolyte, agitation, and additives greatly impact the crystal morphology of the deposit. This methodology can be used simply and economically to provide high-area films in selective regions.
Date: June 7, 1999
Creator: Ricco, A.J.; Staton, A.W. & Yelton, W.G.
System: The UNT Digital Library
Molten Salt Fuel Cycle Requirements for ADTT Applications (open access)

Molten Salt Fuel Cycle Requirements for ADTT Applications

The operation of an ADT system with the associated nuclear reactions has a profound effect upon the chemistry of the fuel - especially with regards to container compatibility and the chemical separations that may be required. The container can be protected by maintaining the redox chemistry within a relatively narrow, non-corrosive window. Neutron economy as well as other factors require a sophisticated regime of fission product separations. Neither of these control requirements has been demonstrated on the scale or degree of sophistication necessary to support an ADT device. We review the present situation with respect to fluoride salts, and focus on the critical issues in these areas which must be addressed. One requirement for advancement in this area - a supply of suitable materials - will soon be fulfilled by the remediation of ORNL�s Molten Salt Reactor Experiment, and the removal of a total of 11,000 kg of enriched (Li-7 > 99.9%) coolant, flush, and fuel salts.
Date: June 7, 1999
Creator: Del Cul, G.D.; Toth, L.M. & Williams, D.F.
System: The UNT Digital Library
A portable data acquisition and control system for waste treatment development (open access)

A portable data acquisition and control system for waste treatment development

Lawrence Livermore National Laboratory (LLNL) has developed a Portable Data Acquisition and Control (PDAC) System that is basically a laboratory-scale Program Logic Control (PLC). This system can obtain signals from numerous sensors (e.g., pH, level, pressure, and flow meters), open and close valves, and turn on and off pumps. The data can then be saved on a spreadsheet or displayed as a graph/indicator in real-time on a computer screen.
Date: June 7, 1999
Creator: Bowers, J & Rogers, H
System: The UNT Digital Library
Radiochemical analysis using Empore{trademark} Rad Disks. (open access)

Radiochemical analysis using Empore{trademark} Rad Disks.

A solid-phase extraction technique that isolates specific radionuclides (i.e., {sup 89/90}Sr, {sup 226/228}Ra, {sup 99}Tc) from surface, ground, and drinking waters is described. The analyte is isolated by pulling a sample through an appropriate Empore{trademark} Rad Disk with a vacuum, and the disk is subsequently assayed by a suitable counting technique. The method has both laboratory and field applications. Interferences are discussed.
Date: June 7, 1999
Creator: Smith, L. L.
System: The UNT Digital Library
Seismic Image Segmentation (open access)

Seismic Image Segmentation

Image segmentation is a standard low-level task in computer vision. We demonstrate how the segmentation of seismic images can assist in geologic interpretation. An image segmentation technique is applied to images of the acoustic impedance. A salient feature of the resulting segments is that the hydrocarbon-bearing regions are characterized by a finer segmentation than the other regions. A modified apparent polarity attribute is introduced, and images of this attribute are segmented. The boundaries of the resulting segments pass through the minima and maxima of the acoustic impedance in a manner that allows us to segment the acoustic impedance image into layers of high and low acoustic impedance. Our methods can assist in segmentation of acoustic impedance images according to lithology or geologic facies.
Date: June 7, 1999
Creator: Wiseman, S.
System: The UNT Digital Library
Voltage breakdown limits at a high material temperature for rapid pulse heating in a vacuum (open access)

Voltage breakdown limits at a high material temperature for rapid pulse heating in a vacuum

The proposed Advanced Hydro Facility (AHF) is required to produce multi-pulse radiographs. Electron beam pulse machines with sub-microsecond repetition are not yet available to test the problem of electron beam propagation through the hydro-dynamically expanding plasma from the nearby previously heated target material. A proposed test scenario includes an ohmically heated small volume of target material simulating the electron beam heating, along with an actual electron beam pulse impinging on nearby target material. A pulse power heating circuit was tested to evaluate the limits of pulse heating a small volume of material to tens of kilo-joules per gram. The main pulse heating time (50 to 100 ns) was to simulate the electron beam heating of a converter target material. To avoid skin heating non-uniformity a longer time scale pulse of a few microseconds first heats the target material to a few thousand degrees near the liquid to vapor transition. Under this state the maximum electric field that the current carrying conductor can support is the important parameter for insuring that the 100 ns heating pulse can deposit sufficient power. A small pulse power system was built for tests of this limit. Under cold conditions the vacuum electric field hold-off limit …
Date: June 7, 1999
Creator: Pincosy, P. A. & Speer, R.
System: The UNT Digital Library