Characterization of Plutonium-Bearing Wastes by Chemical Analysis and Analytical Electron Microscopy (open access)

Characterization of Plutonium-Bearing Wastes by Chemical Analysis and Analytical Electron Microscopy

This report summarizes the results of characterization studies of plutonium-bearing wastes produced at the US Department of Energy weapons production facilities. Several different solid wastes were characterized, including incinerator ash and ash heels from Rocky Flats Plant and Los Alamos National Laboratory; sand, stag, and crucible waste from Hanford; and LECO crucibles from the Savannah River Site. These materials were characterized by chemical analysis and analytical electron microscopy. The results showed the presence of discrete PuO2, PuO₂x, and Pu4O7 phases, of about 1micrometer or less in size, in all of the samples examined. In addition, a number of amorphous phases were present that contained plutonium. In all the ash and ash heel samples examined, plutonium phases were found that were completely surrounded by silicate matrices. Consequently, to achieve optimum plutonium recovery in any chemical extraction process, extraction would have to be coupled with ultrafine grinding to average particle sizes of less than 1 micrometer to liberate the plutonium from the surrounding inert matrix.
Date: September 1995
Creator: Behrens, R. G.; Buck, E. C.; Dietz, N. L.; Bates, J. K.; Van Deventer, E. & Chaiko, David J.
System: The UNT Digital Library
Automotive Vehicle Sensors (open access)

Automotive Vehicle Sensors

This report is an introduction to the field of automotive vehicle sensors. It contains a prototype data base for companies working in automotive vehicle sensors, as well as a prototype data base for automotive vehicle sensors. A market analysis is also included.
Date: September 1995
Creator: Sheen, S. H.; Raptis, A. C. & Moscynski, M. J.
System: The UNT Digital 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 (open access)

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

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.
Date: September 1995
Creator: Coskun, Erhan & Kwong, Man Kam
System: The UNT Digital Library