A Mechanism for Enhanced Low-Dose-Rate Sensitivity of Bipolar Transistors (open access)

A Mechanism for Enhanced Low-Dose-Rate Sensitivity of Bipolar Transistors

None
Date: September 26, 2000
Creator: Hjalmarson, Harold P.; Witczak, Steven C.; Schultz, Peter A.; Bowman, Duane J. & Fleetwood, Daniel M.
Object Type: Article
System: The UNT Digital Library
Kinetics and Mechanisms of Formation of Magnesite from Hydromagnesite in Brine (open access)

Kinetics and Mechanisms of Formation of Magnesite from Hydromagnesite in Brine

None
Date: September 26, 2000
Creator: Zhang, Pengchu; Anderson, Howard L.; Kelly, John W.; Krumhansl, James L. & Papenguth, Hans W.
Object Type: Article
System: The UNT Digital Library
Transmission electron microscopy investigation of texture development in magnesium oxide buffer layers. (open access)

Transmission electron microscopy investigation of texture development in magnesium oxide buffer layers.

None
Date: September 26, 2000
Creator: Koritala, R. E.; Chudzik, M. P.; Balachandran, U.; Luo, Z. P.; Miller, D. J. & Kannewurf, C. R.
Object Type: Article
System: The UNT Digital Library
What's New: Fall 2001 Update (open access)

What's New: Fall 2001 Update

Bi-annual newsletter features articles on HEV/LSV compliance advisory, biodiesel fuel use growth in 2000, Texas Department of Transportation, and the Credit Trades Bulletin Board.
Date: September 26, 2001
Creator: White, H.
Object Type: Book
System: The UNT Digital Library
Thermal Decomposition of Radiation-Damaged Polystyrene (open access)

Thermal Decomposition of Radiation-Damaged Polystyrene

The radiation-damaged polystyrene material (''polycube'') used in this study was synthesized by mixing a high-density polystyrene (''Dylene Fines No. 100'') with plutonium and uranium oxides. The polycubes were used on the Hanford Site in the 1960s for criticality studies to determine the hydrogen-to-fissile atom ratios for neutron moderation during processing of spent nuclear fuel. Upon completion of the studies, two methods were developed to reclaim the transuranic (TRU) oxides from the polymer matrix: (1) burning the polycubes in air at 873 K; and (2) heating the polycubes in the absence of oxygen and scrubbing the released monomer and other volatile organics using carbon tetrachloride. Neither of these methods was satisfactory in separating the TRU oxides from the polystyrene. Consequently, the remaining polycubes were sent to the Hanford Plutonium Finishing Plant (PFP) for storage. Over time, the high dose of alpha and gamma radiation has resulted in a polystyrene matrix that is highly cross-linked and hydrogen deficient and a stabilization process is being developed in support of Defense Nuclear Facility Safety Board Recommendation 94-1. Baseline processes involve thermal treatment to pyrolyze the polycubes in a furnace to decompose the polystyrene and separate out the TRU oxides. Thermal decomposition products from this …
Date: September 26, 2000
Creator: Klinger, J Abrefah GS
Object Type: Report
System: The UNT Digital Library
Equation of State Measurements of Materials Using a Three-Stage Gun to Impact Velocities of 11km/s (open access)

Equation of State Measurements of Materials Using a Three-Stage Gun to Impact Velocities of 11km/s

Understanding high pressure behavior of homogeneous as well as heterogeneous materials is necessary in order to address the physical processes associated with hypervelocity impact events related to space science applications including orbital debris impact and impact lethality. At very high impact velocities, material properties will be subjugated to phase-changes, such as melting and vaporization. These phase states cannot be obtained through conventional gun technology. These processes need to be represented accurately in hydrodynamic codes to allow credible computational analysis of impact events resulting from hypervelocity impact. In this paper, techniques that are being developed and implemented to obtain the needed shock loading parameters (Hugoniot states) for material characterization studies, namely shock velocity and particle velocity, will be described at impact velocities up to 11 km/s. What is new in this report is that these techniques are being implemented for use at engagement velocities never before attained utilizing two-stage light-gas gun technology.
Date: September 26, 2000
Creator: Reinhart, William D.; Chhabildas, Lalit C.; Carroll, Daniel E.; Thornhill, T. G. & Winfree, N. A.
Object Type: Article
System: The UNT Digital Library
Special Analysis for Disposal of High-Concentration I-129 Waste in the Intermediate-Level Vaults at the E-Area Low-Level Waste Facility (open access)

Special Analysis for Disposal of High-Concentration I-129 Waste in the Intermediate-Level Vaults at the E-Area Low-Level Waste Facility

This revision was prepared to address comments from DOE-SR that arose following publication of revision 0. This Special Analysis (SA) addresses disposal of wastes with high concentrations of I-129 in the Intermediate-Level (IL) Vaults at the operating, low-level radioactive waste disposal facility (the E-Area Low-Level Waste Facility or LLWF) on the Savannah River Site (SRS). This SA provides limits for disposal in the IL Vaults of high-concentration I-129 wastes, including activated carbon beds from the Effluent Treatment Facility (ETF), based on their measured, waste-specific Kds.
Date: September 26, 2000
Creator: Collard, L.B.
Object Type: Report
System: The UNT Digital Library
ADVISOR Users Conference Proceedings 2000 - Final Electronic version (open access)

ADVISOR Users Conference Proceedings 2000 - Final Electronic version

This is a compilation of papers presented at the ADVISOR (ADvanced Vehicle SimulatOR) Users Conference held in Costa Mesa, California, August 24-25, 2000. Major topics of the conference included modeling and simulation; partnering with the auto industry; co-simulation: partnering with the software industry in optimization and thermal modeling and geometric and mechanical modeling; forward-looking simulations coupled with ADVISOR; new concepts from universities; validation, vehicle development and applications.
Date: September 26, 2000
Creator: National Renewable Energy Lab
Object Type: Article
System: The UNT Digital Library
Update on the National Center for Gear Metrology (open access)

Update on the National Center for Gear Metrology

Traceability to national or international standards is clearly required by commercial sector standards including ISO 9001:1994 (Ref. 1), ISO/IEC Guide 25 (Ref. 2), and the US equivalent of ISO/IEC Guide 25-ANSI/NCSL Z540-2-1997 (Ref. 3). In the draft replacement to ISO/IEC Guide 25-ISO 17025; measurements, not just equipment, must be traceable to SI units or reference to a natural constant. The implications of traceability to the US gear industry are significant. In order to meet the standards, either gear manufacturers must have calibrated artifacts or must establish their own traceability to SI units.
Date: September 26, 2000
Creator: Cox, B. L.
Object Type: Article
System: The UNT Digital Library
SNS Inner Plug Shipping Cask Analysis (open access)

SNS Inner Plug Shipping Cask Analysis

Calculations were performed to evaluate the dose rates outside the shipping cask containing the Spallation Neutron Source (SNS) inner plug assembly. The analysis consisted of simulating the proton beam interaction with the SNS target, activation calculations with the determined neutron flux levels and assumed SNS operation schedule, and calculation of the decay gamma-rays propagation through the inner plug and shipping cask. Several materials were considered for the inner plug. The results provide guidance for the finalization of the plug design.
Date: September 26, 2001
Creator: Remec, I
Object Type: Article
System: The UNT Digital Library
Bent-Beam Electrothermal Actuators: Linear and Rotary MicroEngines (open access)

Bent-Beam Electrothermal Actuators: Linear and Rotary MicroEngines

None
Date: September 26, 2000
Creator: Park, Jae-Sung; Chu, Larry L.; Oliver, Andrew D. & Gianchandani, Yogesh B.
Object Type: Article
System: The UNT Digital Library
Nanostructured materials for microstructural control of thermal properties. (open access)

Nanostructured materials for microstructural control of thermal properties.

None
Date: September 26, 2000
Creator: Eastman, J. A.; Soyez, G.; Bai, G.-R. & Thompson, L. J.
Object Type: Article
System: The UNT Digital Library
Alpha-particle Measurements Needed for Burning Plasma Experiments (open access)

Alpha-particle Measurements Needed for Burning Plasma Experiments

The next major step in magnetic fusion studies will be the construction of a burning plasma (BP) experiment where the goals will be to achieve and understand the plasma behavior with the internal heating provided by fusion-generated alpha particles. Two devices with these physics goals have been proposed: the International Thermonuclear Experimental Reactor (ITER) and the Fusion Ignition Research Experiment (FIRE). Extensive conceptual design work for the instrumentation to try to meet the physics demands has been done for these devices, especially ITER. This article provides a new look at the measurements specifically important for understanding the physics aspects of the alpha particles taking into account two significant events. The first is the completion of physics experiments on the Joint European Torus (JET) and the Tokamak Fusion Test Reactor (TFTR) with deuterium-tritium fueling with the first chances to study alpha physics and the second is the realization that relatively compact plasmas, making use of advanced tokamak plasma concepts, are the most probable route to burning plasmas and ultimately a fusion reactor.
Date: September 26, 2001
Creator: Young, Kenneth M.
Object Type: Report
System: The UNT Digital Library
Quantifying the fuel use and greenhouse gas reduction potential of electric and hybrid electric vehicles. (open access)

Quantifying the fuel use and greenhouse gas reduction potential of electric and hybrid electric vehicles.

None
Date: September 26, 2000
Creator: Patterson, P. P.; Bohn, T.; Hazard, N. Smigh, M. & Wn
Object Type: Article
System: The UNT Digital Library
VOC Control in Kraft Mills - Final Report: Task A and Task B (open access)

VOC Control in Kraft Mills - Final Report: Task A and Task B

The formation of volatile organic compounds (VOCs), such as methanol, in kraft mills has been an environmental concern. Methanol is soluble in water and can increase the biochemical oxygen demand. Furthermore, it can also be released into atmosphere at the process temperatures of kraft mill-streams. The Cluster Rule of the EPA now requires the control of the release of methanol in pulp and paper mills. This research program was conducted to develop a computer simulation tool for mills to predict VOC air emissions. To achieve the objective of the research program, much effort was made in the development of analytical techniques for the analysis of VOC and determination of vapor liquid partitioning coefficient of VOCs in kraft mill-streams using headspace gas chromatography. With the developed analytical tool, methanol formation in alkaline pulping was studied in laboratory to provide benchmark data of the amount of methanol formation in pulping in kraft mills and for the validation of VOC formation and vapor-liquid equilibrium submodels. Several millwide air and liquid samplings were conducted using the analytical tools developed to validate the simulation tool. The VOC predictive simulation model was developed based on the basic chemical engineering concepts, i.e., reaction kinetics, vapor liquid equilibrium, …
Date: September 26, 2001
Creator: Zhu, J.Y.; Chai, X.-S.; Edwards, L.L.; Gu, Y.; Teja, A.S.; Kirkman, A.G. et al.
Object Type: Report
System: The UNT Digital Library
Neutronic feasibility studies for LEU conversion of the HFR Petten Reactor. (open access)

Neutronic feasibility studies for LEU conversion of the HFR Petten Reactor.

Design and safety analyses to determine an optimum LEU fuel assembly design using U{sub 3}Si{sub 2}-Al fuel with up to 4.8 g/cm{sup 3} for conversion of the HFR Petten reactor were performed by the RERTR program in cooperation with the Joint Research Centre and NRG. Credibility of the calculational methods and models were established by comparing calculations with recent measurements by NRG for a core configuration setup for this purpose. This model and methodology were then used to study various LEU fissile loading and burnable poison options that would satisfy specific design criteria.
Date: September 26, 2000
Creator: Hanan, N. A.; Deen, J. R. & Matos, J. E.
Object Type: Article
System: The UNT Digital Library
Review of Upscaling Methods for Describing Unsaturated Flow (open access)

Review of Upscaling Methods for Describing Unsaturated Flow

The representation of small-scale features can be a challenge when attempting to model unsaturated flow in large domains. Upscaling methods offer the possibility of reducing the amount of resolution required to adequately simulate such a problem. In this report, the various upscaling techniques that are discussed in the literature are reviewed. The following upscaling methods have been identified from the literature: (1) stochastic methods, (2) renormalization methods, and (3) volume averaging and homogenization methods; in addition, a final technique, full resolution numerical modeling, is also discussed. Each of these techniques has its advantages and disadvantages. The trade-off is a reduction in accuracy in favor of a method that is easier to employ. For practical applications, the most reasonable approach appears to be one in which any of the upscaling methods identified above maybe suitable for upscaling in regions where the variations in the parameter fields are small. For regions where the subsurface structure is more complex, only the homogenization and volume averaging methods are probably suitable. With the continual increases in computational capacity, fill-resolution numerical modeling may in many instances provide a tractable means of solving the flow problem in unsaturated systems.
Date: September 26, 2000
Creator: Wood, BD
Object Type: Report
System: The UNT Digital Library
Diagnostics of ST Plasmas in NSTX: Challenges and Opportunities (open access)

Diagnostics of ST Plasmas in NSTX: Challenges and Opportunities

This paper will highlight some of the challenges and opportunities present in the diagnosis of spherical torus (ST) plasmas on the National Spherical Torus Experiment (NSTX) and discuss the corresponding diagnostic development that is presently underway. After a brief description of diagnostic systems currently installed, examples of ST-specific diagnostic challenges will be highlighted, as will another case, where the ST configuration offers opportunities for new measurements.
Date: September 26, 2001
Creator: Johnson, D.; Efthimion, P.; Foley, J.; Jones, B.; Mazzucato, E.; Park, H. et al.
Object Type: Report
System: The UNT Digital Library
Reuse of concrete within DOE from decontamination and decommissioning projects. (open access)

Reuse of concrete within DOE from decontamination and decommissioning projects.

None
Date: September 26, 2000
Creator: Tripp, J. L.; Phillips, A. M.; Meservey, R. H.; Chen, S. Y.; Kamboj, S. & Arnish, J.
Object Type: Article
System: The UNT Digital Library
Rapid thermal annealing of InAs/GaAs quantum dots under a GaAs proximity cap (open access)

Rapid thermal annealing of InAs/GaAs quantum dots under a GaAs proximity cap

None
Date: September 26, 2001
Creator: Babinski, Adam; Jasinski, J.; Bozek, R.; Szepielow, A. & Baranowski, J. M.
Object Type: Article
System: The UNT Digital Library
Development of a One-Equation Transition/Turbulence Model (open access)

Development of a One-Equation Transition/Turbulence Model

This paper reports on the development of a unified one-equation model for the prediction of transitional and turbulent flows. An eddy viscosity - transport equation for non-turbulent fluctuation growth based on that proposed by Warren and Hassan (Journal of Aircraft, Vol. 35, No. 5) is combined with the Spalart-Allmaras one-equation model for turbulent fluctuation growth. Blending of the two equations is accomplished through a multidimensional intermittence function based on the work of Dhawan and Narasimha (Journal of Fluid Mechanics, Vol. 3, No. 4). The model predicts both the onset and extent of transition. Low-speed test cases include transitional flow over a flat plate, a single element airfoil, and a multi-element airfoil in landing configuration. High-speed test cases include transitional Mach 3.5 flow over a 5{degree} cone and Mach 6 flow over a flared-cone configuration. Results are compared with experimental data, and the spatial accuracy of selected predictions is analyzed.
Date: September 26, 2000
Creator: EDWARDS,JACK R.; ROY,CHRISTOPHER J.; BLOTTNER,FREDERICK G. & HASSAN,HASSAN A.
Object Type: Article
System: The UNT Digital Library
VOC Control in Kraft Mills (open access)

VOC Control in Kraft Mills

The formation of volatile organic compounds (VOCs), such as methanol, in kraft mills has been an environmental concern. Methanol is soluble in water and can increase the biochemical oxygen demand. Furthermore, it can also be released into atmosphere at the process temperatures of kraft mill-streams. The Cluster Rule of the EPA now requires the control of the release of methanol in pulp and paper mills. This research program was conducted to develop a computer simulation tool for mills to predict VOC air emissions. To achieve the objective of the research program, much effort was made in the development of analytical techniques for the analysis of VOC and determination of vapor liquid partitioning coefficient of VOCs in kraft mill-streams using headspace gas chromatography. With the developed analytical tool, methanol formation in alkaline pulping was studied in laboratory to provide benchmark data of the amount of methanol formation in pulping in kraft mills and for the validation of VOC formation and vapor-liquid equilibrium submodels. Several millwide air and liquid samplings were conducted using the analytical tools developed to validate the simulation tool. The VOC predictive simulation model was developed based on the basic chemical engineering concepts, i.e., reaction kinetics, vapor liquid equilibrium, …
Date: September 26, 2001
Creator: Zhu, J.Y.; Chai, X.-S.; Edwards, L.L.; Gu, Y.; Teja, A.S.; Kirkman, A.G. et al.
Object Type: Report
System: The UNT Digital Library
Examination of the Mesoscopic Scale Response of Shock Compressed Heterogeneous Materials Using a Line-Imaging Velocity Interferometer (open access)

Examination of the Mesoscopic Scale Response of Shock Compressed Heterogeneous Materials Using a Line-Imaging Velocity Interferometer

None
Date: September 26, 2000
Creator: Trott, Wayne M.; Castañeda, Jaime N.; O'Hare, John J.; Knudson, Marcus D.; Chhabildas, Lalit C.; Baer, M. R. et al.
Object Type: Article
System: The UNT Digital Library
Innovative Approaches to Resolving Orphan Materials Problems in the DOE Complex (open access)

Innovative Approaches to Resolving Orphan Materials Problems in the DOE Complex

None
Date: September 26, 2000
Creator: Polansky, Gary F. & Parks, David L.
Object Type: Article
System: The UNT Digital Library