You limited your search to:

  Partner: UNT Libraries Government Documents Department
 Collection: Technical Report Archive and Image Library
Parallel Solution of the Time-Dependent Ginzburg-Landau Equations and other Experiences using BlockComm-Chameleon and PCN on the IBM SP, Intel iPSC/860, and Clusters of Workstations

Parallel Solution of the Time-Dependent Ginzburg-Landau Equations and other Experiences using BlockComm-Chameleon and PCN on the IBM SP, Intel iPSC/860, and Clusters of Workstations

Date: September 1995
Creator: Coskun, Erhan & Kwong, Man Kam
Description: Time-dependent Ginzburg-Landau (TDGL) equations are considered for modeling a thin-film finite size superconductor placed under magnetic field. The problem then leads to the use of so-called natural boundary conditions. Computational domain is partitioned into subdomains and bond variables are used in obtaining the corresponding discrete system of equations. An efficient time-differencing method based on the Forward Euler method is developed. Finally, a variable strength magnetic field resulting in a vortex motion in Type II High-critical-temperature superconducting films is introduced. The authors tackled the problem using two different state-of-the-art parallel computing tools: BlockComm/Chameleon and PCN. They had access to two high-performance distributed memory supercomputers: the Intel iPSC/860 and IBM SP1. They also tested the codes using, as a parallel computing environment, a cluster of Sun Sparc workstations.
Contributing Partner: UNT Libraries Government Documents Department
The DART Dispersion Analysis Research Tool:  a Mechanistic Model for Predicting Fission-Product-Induced Swelling of Aluminum Dispersion Fuels : User's Guide for Mainframe, Workstation, and Personal Computer

The DART Dispersion Analysis Research Tool: a Mechanistic Model for Predicting Fission-Product-Induced Swelling of Aluminum Dispersion Fuels : User's Guide for Mainframe, Workstation, and Personal Computer

Date: August 1995
Creator: Rest, J.
Description: This report describes the primary physical models that form the basis of the DART mechanistic computer model for calculating fission-product-induced swelling of aluminum dispersion fuels; the calculated results are compared with test data. In addition, DART calculates irradiation-induced changes in the thermal conductivity of the dispersion fuel, as well as fuel restructuring due to aluminum fuel reaction, amorphization, and recrystallization. Input instructions for execution on mainframe, workstation, and personal computers are provided, as is a description of DART output. The theory of fission gas behavior and its effect on fuel swelling is discussed. The behavior of these fission products in both crystalline and amorphous fuel and in the presence of irradiation-induced recrystallization and crystalline-to-amorphous-phase change phenomena is presented, as are models for these irradiation-induced processes.
Contributing Partner: UNT Libraries Government Documents Department
Implementation and Validation of a Reynolds Stress Model in the COMMIX-1C/RSM and CAPS-3D/RSM Codes

Implementation and Validation of a Reynolds Stress Model in the COMMIX-1C/RSM and CAPS-3D/RSM Codes

Date: August 1995
Creator: Chang, F. C. & Bottoni, M.
Description: A Reynolds stress model (RSM) of turbulence, based on seven transport equations, has been linked to the COMMIX-1C/RSM and CAPS-3D/RSM computer codes. Six of the equations model the transport of the components of the Reynolds stress tensor and the seventh models the dissipation of turbulent kinetic energy. When a fluid is heated, four additional transport equations are used: three for the turbulent heat fluxes and one for the variance of temperature fluctuations. All of the analytical and numerical details of the implementation of the new turbulence model are documented. The model was verified by simulation of homogeneous turbulence.
Contributing Partner: UNT Libraries Government Documents Department
Minimum Additive Waste Stabilization (MAWS), Phase 1: Soil Washing Final Report

Minimum Additive Waste Stabilization (MAWS), Phase 1: Soil Washing Final Report

Date: August 1995
Creator: Argonne National Laboratory
Description: As a result of the U.S. Department of Energy's environmental restoration and technology development activities, GTS Duratek, Inc., and its subcontractors have demonstrated an integrated thermal waste treatment system at Fernald, OH, as part the Minimum Additive Waste Stabilization (MAWS) Program. Specifically, MAWS integrates soil washing, vitrification of mixed waste streams, and ion exchange to recycle and remediate process water to achieve, through a synergistic effect, a reduction in waste volume, increased waste loading, and production of a durable, leach-resistant, stable waste form suitable for disposal. This report summarizes the results of the demonstration/testing of the soil washing component of the MAWS system installed at Fernald (Plant 9). The soil washing system was designed to (1) process contaminated soil at a rate of 0.25 cubic yards per hour; (2) reduce overall waste volume and provide consistent-quality silica sand and contaminant concentrates as raw material for vitrification; and (3) release clean soil with uranium levels below 35 pCi/g. Volume reductions expected ranged from 50-80 percent; the actual volume reduction achieved during the demonstration reached 66.5 percent. The activity level of clean soil was reduced to as low as 6 pCi/g from an initial average soil activity level of 17.6 pCi/g (the ...
Contributing Partner: UNT Libraries Government Documents Department
Physics Division Annual Review: April 1, 1994-March 31, 1995

Physics Division Annual Review: April 1, 1994-March 31, 1995

Date: August 1995
Creator: Argonne National Laboratory. Physics Division.
Description: Annual report of activities of the Argonne National Laboratory Physics Division, including heavy-ion nuclear physics research, operation and development of ATLAS, medium-energy nuclear physics research, theoretical physics, atomic and molecular physics research.
Contributing Partner: UNT Libraries Government Documents Department
Validation of the Generic TRUEX Model Using Data from TRUEX Demonstrations with Actual High-Level Waste

Validation of the Generic TRUEX Model Using Data from TRUEX Demonstrations with Actual High-Level Waste

Date: August 1995
Creator: Regalbuto, M. C.; Aase, S. B. & Vandegrift, G. F.
Description: The Generic TRUEX Model (GTM) was used to simulate three different counter-current flowsheet tests performed using mixer-settlers that had been carried out prior to 1993 in the Chemical Processing Facility, Tokai-works, of the Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan. The feed for the PNC runs was the highly active raffinate from reprocessing of spent fuel from fast breeder reactors. The PNC demonstration runs were planned without using the GTM. Results predicted by the GTM and those obtained experimentally by PNC for the three demonstration runs are compared. Effects of stage efficiency, nitrate complexation, temperature, and equipment type are also included.
Contributing Partner: UNT Libraries Government Documents Department
Aqueous Biphasic Extraction of Uranium and Thorium from Contaminated Soils : Final Report

Aqueous Biphasic Extraction of Uranium and Thorium from Contaminated Soils : Final Report

Date: July 1995
Creator: Chaiko, David J.; Gartelmann, J.; Henriksen, J. L.; Krause, T. R.; Deepak; Vojta, Y. et al.
Description: The aqueous biphasic extraction (ABE) process for soil decontamination involves the selective partitioning of solutes and fine particulates between two immiscible aqueous phases. The biphase system is generated by the appropriate combination of a water-soluble polymer (e.g., polyethylene glycol) with an inorganic salt (e.g., sodium carbonate). Selective partitioning results in 99 to 99.5% of the soil being recovered in the cleaned-soil fraction, while only 0.5 to 1% is recovered in the contaminant concentrate. The ABE process is best suited to the recovery of ultrafine, refractory material from the silt and clay fractions of soils. During continuous countercurrent extraction tests with soil samples from the Fernald Environmental Management Project site (Fernald, OH), particulate thorium was extracted and concentrated between 6- and 16-fold, while the uranium concentration was reduced from about 500 mg/kg to about 77 mg/kg. Carbonate leaching alone was able to reduce the uranium concentration only to 146 mg/kg. Preliminary estimates for treatment costs are approximately $160 per ton of dry soil. A detailed flowsheet of the ABE process is provided.
Contributing Partner: UNT Libraries Government Documents Department
Extraction of Long-Lived Radionuclides from Caustic Hanford Tank Waste Supernatants

Extraction of Long-Lived Radionuclides from Caustic Hanford Tank Waste Supernatants

Date: July 1995
Creator: Chaiko, David J.; Mertz, C. J.; Vojta, Y.; Henriksen, J. L.; Neff, R. & Takeuchi, M.
Description: A series of polymer-based extraction systems, based on the use of polyethylene glycols (PEGs) or polypropylene glycols (PPGs), was demonstrated to be capable of selective extraction and recovery of long-lived radionuclides, such as Tc-99 and I-129, from Hanford SY-101 tank waste, neutralized current acid waste, and single-shell tank waste simulants. During the extraction process, anionic species like TcO₄⁻ and I⁻ are selectively transferred to the less dense PEG-rich aqueous phase. The partition coefficients for a wide range of inorganic cations and anions, such as sodium, potassium, aluminum, nitrate, nitrite, and carbonate, are all less than one. The partition coefficients for pertechnetate ranged from 12 to 50, depending on the choice of waste simulant and temperature. The partition coefficient for iodide was about 5, while that of iodate was about 0.25. Irradiation of the PEG phase with gamma-ray doses up to 20 Mrad had no detectable effect on the partition coefficients. The most selective extraction systems examined were those based on PPGs, which exhibited separation factors in excess of 3000 between TcO₄⁻ and NO₃⁻/NO₂⁻. An advantage of the PPG-based system is minimization of secondary waste production. These studies also highlighted the need for exercising great care in extrapolating the partitioning behavior ...
Contributing Partner: UNT Libraries Government Documents Department
Information Exchange within the U.S. Department of Energy Pollution Prevention Community

Information Exchange within the U.S. Department of Energy Pollution Prevention Community

Date: July 1995
Creator: Thuot, James R.
Description: Improving Pollution Prevention and Waste Minimization Program (PP/WMIN) technologies, actions, and culture could be an important cost-cutting step for the US Department of Energy (DOE). Communicating ideas, concepts, process changes, and achievements is essential for the success of this program. The need to openly communicate ideas and concepts in a cost-effective manner is essential in an organization that has such diverse components as research and development, weapons production, and power generation. This approach is in contrast to the historic DOE culture developed within the cold war period in which compartmentalization, independence, and secrecy were stressed. DOE has now recognized that for any pollution prevention program to be successful, the many diverse elements of the organization must share information. Avenues for such information exchange are examined in this report.
Contributing Partner: UNT Libraries Government Documents Department
Nonlinear Dynamics of a Stack/Cable System

Nonlinear Dynamics of a Stack/Cable System

Date: July 1995
Creator: Cai, Y. & Chen, Shoei-Sheng
Description: In this study, we developed a coupled model of wind-induced vibration of a stack, based on an unsteady-flow theory and nonlinear dynamics of the stack's heavy elastic suspended cables. Numerical analysis was performed to identify excitation mechanisms. The stack was found to be excited by vortex shedding. Once lock-in resonance occurred, the cables were excited by the transverse motion of the stack. Large-amplitude oscillations of the cables were due to parametric resonance. Appropriate techniques have been proposed to alleviate the vibration problem.
Contributing Partner: UNT Libraries Government Documents Department