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10. international mouse genome conference (open access)

10. international mouse genome conference

Ten years after hosting the First International Mammalian Genome Conference in Paris in 1986, Dr. Jean-Louis Guenet presided over the Tenth Conference at the Pasteur Institute, October 7--10, 1996. The 1986 conference was a satellite to the Human Gene Mapping Workshop and had approximately 50 attendees. The 1996 meeting was attended by 300 scientists from around the world. In the interim, the number of mapped loci in the mouse increased from 1,000 to over 20,000. This report contains a listing of the program and its participants, and two articles that review the meeting and the role of the laboratory mouse in the Human Genome project. More than 200 papers were presented at the conference covering the following topics: International mouse chromosome committee meetings; Mutant generation and identification; Physical and genetic maps; New technology and resources; Chromatin structure and gene regulation; Rate and hamster genetic maps; Informatics and databases; and Quantitative trait analysis.
Date: December 31, 1996
Creator: Meisler, M. H.
System: The UNT Digital Library
The 1996 meeting of the national technical workgroup on mixed waste thermal treatment (open access)

The 1996 meeting of the national technical workgroup on mixed waste thermal treatment

The National Technical Workgroup on Mixed Waste Thermal Treatment held its annual meeting in Atlanta Georgia on March 12-14, 1996. The National Technical Workgroup (NTW) and this meeting were sponsored under an interagency agreement between EPA and DOE. The 1996 Annual Meeting was hosted by US DOE Oak Ridge Operations in conjunction with Lockheed Martin Energy Systems - Center for Waste Management. A new feature of the annual meeting was the Permit Writer Panel Session which provided an opportunity for the state and federal permit writers to discuss issues and potential solutions to permitting mixed waste treatment systems. In addition, there was substantial discussion on the impacts of the Waste Combustion Performance Standards on mixed waste thermal treatment which are expected to proposed very soon. The 1996 meeting also focussed on two draft technical resource documents produced by NTW on Waste Analysis Plans and Compliance Test Procedures. Issues discussed included public involvement, waste characterization, and emission issues.
Date: December 31, 1996
Creator: unknown
System: The UNT Digital Library
3D simulation studies of tokamak plasmas using MHD and extended-MHD models (open access)

3D simulation studies of tokamak plasmas using MHD and extended-MHD models

The M3D (Multi-level 3D) tokamak simulation project aims at the simulation of tokamak plasmas using a multi-level tokamak code package. Several current applications using MHD and Extended-MHD models are presented; high-{beta} disruption studies in reversed shear plasmas using the MHD level MH3D code, {omega}{sub *i} stabilization and nonlinear island saturation of TAE mode using the hybrid particle/MHD level MH3D-K code, and unstructured mesh MH3D{sup ++} code studies. In particular, three internal mode disruption mechanisms are identified from simulation results which agree which agree well with experimental data.
Date: December 31, 1996
Creator: Park, W.; Chang, Z.; Fredrickson, E. & Fu, G. Y.
System: The UNT Digital Library
The ABB LEBS system design (open access)

The ABB LEBS system design

The objectives of the U.S. Department of Energy (DOE) {open_quotes}Engineering Development of Advanced Coal-Fired Low-Emission Boiler Systems{close_quotes} (LEBS) project are to dramatically improve environmental performance of future pulverized coal-fired power plants, to increase their efficiency and to reduce their cost of electricity using near-term technologies, i.e., advanced technologies that are partially developed. The overall objective is to expedite commercialization of the technologies that are developed. The paper describes the work by the ABB team on the LEBS project which is part of the DOE`s Combustion 2000 Program. A major deliverable of the Project is the design of a 400 MWe commercial generating unit (CGU). The design being developed by the ABB team is projected to meet all the project objectives and to reduce emissions of NO{sub x}, SO{sub 2} and particulates to one-third to one-sixth NSPS limits while increasing net station efficiency significantly and reducing the cost of electricity. Development activities supporting the design work are described in the paper.
Date: December 31, 1996
Creator: Regan, John W.; Davidson, Michael J.; vonHein, Robert J. & Wesnor, James D.
System: The UNT Digital Library
An abstract-device interface for implementing portable parallel-I/O interfaces (open access)

An abstract-device interface for implementing portable parallel-I/O interfaces

Portable parallel programming has been hampered by the lack of a single, standard, portable application-programmer`s interface (API) for parallel I/O. Instead, the programmer must choose from several different APIs, many of which are not portable. To alleviate this problem, the authors have developed an abstract-device interface for parallel I/O, called ADIO. ADIO is not intended as a new API; rather, it is a strategy for implementing other APIs in a simple, portable, and efficient manner. ADIO facilitates the implementation of any existing or new API on any existing or new file system. ADIO thus enables users to experiment with different APIs, a feature that, they think, would help in the definition of a standard API. It also makes existing applications portable across a wide range of platforms. In this paper, they introduce the concept of ADIO. They describe the design of ADIO and its use in implementing APIs. They have currently implemented subsets of the Intel PFS, IBM PIOFS, and MPI-IO APIs on both the PFS and PIOFS file systems. As a result, they are able to run IBM PIOFS applications on the Intel Paragon, Intel PFS applications on the IBM SP, and MPI-IO applications on both systems. They report …
Date: December 31, 1996
Creator: Thakur, R.; Gropp, W. & Lusk, E.
System: The UNT Digital Library
Accelerator break-out group summary (open access)

Accelerator break-out group summary

Interesting developments in accelerators have shown that they can be used as {open_quote}factory{close_quote}-type systems with the choice of technology dependent on the specific requirements of the application. The status and future possibilities for cyclotrons and linear accelerators are compared briefly, based on discussions at a break-out session on accelerators. Only high power systems with beam powers in excess of a MW average power were considered.
Date: December 31, 1996
Creator: Schriber, S.O. & Mandrillon, P.
System: The UNT Digital Library
Acoustically enhanced remediation, Phase 2: Technology scaling (open access)

Acoustically enhanced remediation, Phase 2: Technology scaling

Weiss Associates is conducting the following three phase program investigating the in-situ application of acoustically enhanced remediation (AER) of contaminated unconsolidated soil and ground water under both saturated and unsaturated conditions: Phase I-- laboratory scale parametric investigation; Phase II--technology Scaling; and Phase III--large scale field tests. AER addresses the need for NAPL (either lighter or denser than water: LNAPL or DNAPL, respectively) in high and low permeability sediments, and the remediation of other types of subsurface contaminants (e.g., metals, radionuclides) in low permeability soils. This program has been placed in the U.S. Department of Energy`s (DOE`s) DNAPL product. Phase I indicated that AER could be used to effectively remediate NAPL in high permeability soil, and that removal of NAPL from low permeability soil could be increased since the water flux through these soils was significantly increased. Phase II, Technology Scaling, the subject of this paper, focused on (1) evaluating the characteristics of an AER field deployment system, (2) developing DNAPL flow and transport performance data under acoustic excitation, (3) predicting the effect of acoustic remediation in three-dimensional unconsolidated hydrogeologic conditions, (4) conducting an engineering analysis of acoustical sources, and (5) identifying candidate field site(s) for large-scale field testing of the …
Date: December 31, 1996
Creator: Iovenitti, J. L.; Hill, D. G.; Rynne, T. M.; Spadaro, J. F.; Hutchinson, W. & Illangasakere, T.
System: The UNT Digital Library
An acousto-optic tunable filter enhanced CO₂ lidar atmospheric monitor (open access)

An acousto-optic tunable filter enhanced CO₂ lidar atmospheric monitor

The atmospheric monitor conceptual design is based on a pulsed CO{sub 2} laser. The narrow laser lines provide high spectral selectivity in the 9-11 {mu}m region, within the 8-14 {mu}m ``fingerprint`` region where most large molecules have unique spectral absorption signatures. Laser power has been chosen so that topological objects, e.g., trees or buildings, as far as 4 km can be used as backreflectors, but the laser intensity is sufficiently low that the laser beam is eye-safe. Time-of-flight measurements give the distance to the topological reflector. The lidar system is augmented with an acousto-optic tunable filter (AOTF) which measures the thermal emission spectra from 3 to 14 {mu}m with a 3 cm{sup -1} passband. Sensitivity to narrow emission lines is enhanced by derivative spectroscopy in which the passband of the AOTF is dithered via the rf drive. Path-averaged concentrations are determined from the emission intensity and laser- determined range.
Date: December 31, 1996
Creator: Taylor, L. H.; Suhre, D. R. & Mani, S. S.
System: The UNT Digital Library
Advanced Hot-Gas Desulfurization Sorbents (open access)

Advanced Hot-Gas Desulfurization Sorbents

The objective of this project is to develop advanced hot-gas desulfurization sorbents for relatively low temperature application that show stable and high sulfidation reactivity at 343 to 538 {degrees}C. A number of zinc-based formulations will be prepared and screened for testing in a fixed-bed reactor at high pressure (1 to 20 atm) and high temperatures using simulated coal-derived fuel gases. One of the superior formulations will be tested for long- term durability and chemical reactivity in the reactor. To prevent sulfation, catalyst additives will be investigated, which would promote a lower regeneration temperature.
Date: December 31, 1996
Creator: Jothimurugesan, K.; Adeyiga, A. & Gangwal, S.K.
System: The UNT Digital Library
Advanced Low-Temperature Fluid Bed Sorbents (open access)

Advanced Low-Temperature Fluid Bed Sorbents

This paper discusses the results obtained in an ongoing study geared towards developing advanced mixed-metal oxide sorbents for desulfurization of coal-derived fuel gases in the temperature range of 350 to 550{degrees}C. The paper focuses on the study related to the development of durable sorbents suitable for fluidized-bed application and addresses thermodynamic considerations, sulfidation kinetics, regenerability, and the physical and chemical characteristics of a number of novel sorbents.
Date: December 31, 1996
Creator: Abbasian, J.; Slimane, R. B. & Wangerow, J. R.
System: The UNT Digital Library
Advanced materials for solid oxide fuel cells (open access)

Advanced materials for solid oxide fuel cells

Purpose of the research is to improve the properties of current state- of-the-art materials used for SOFCs. The project includes interconnect development, high-performance cathode, electrochemical testing, and accelerated testing. This document reports results of mechanical tests (bend strength, elastic modulus, fracture strength) of acceptor-substituted lanthanum chromite (interconnect material).
Date: December 31, 1996
Creator: Armstrong, T.R.; Stevenson, J. & Paulik, S.
System: The UNT Digital Library
An advanced open path atmospheric pollution monitor for large areas (open access)

An advanced open path atmospheric pollution monitor for large areas

Over 100 million gallons of radioactive and toxic waste materials generated in weapon materials production are stored in 322 tanks buried within large areas at DOE sites. Toxic vapors occur in the tank headspace due to the solvents used and chemical reactions within the tanks. To prevent flammable or explosive concentration of volatile vapors, the headspace are vented, either manually or automatically, to the atmosphere when the headspace pressure exceeds preset values. Furthermore, 67 of the 177 tanks at the DOE Hanford Site are suspected or are known to be leaking into the ground. These underground storage tanks are grouped into tank farms which contain closely spaced tanks in areas as large as 1 km{sup 2}. The objective of this program is to protect DOE personnel and the public by monitoring the air above these tank farms for toxic air pollutants without the monitor entering the tanks farms, which can be radioactive. A secondary objective is to protect personnel by monitoring the air above buried 50 gallon drums containing moderately low radioactive materials but which could also emit toxic air pollutants.
Date: December 31, 1996
Creator: Taylor, L.; Suhre, D. & Mani, S.
System: The UNT Digital Library
Advanced PFBC transient analysis (open access)

Advanced PFBC transient analysis

Transient modeling and analysis of Advanced Pressurized Fluidized Bed Combustion (PFBC) systems is a research area that is currently under investigative study by the United States Department of Energy`s Morgantown Energy Technology Center (METC). The object of the effort is to identify key operating parameters affecting plant performance and then quantify the basic response of major sub-systems to changes in operating conditions. PC-TRAX, a commercially available dynamic software program, was chosen and applied in this modeling and analysis effort. This paper summarizes and describes the development of a series of TRAX-based transient models of Advanced PFBC power plants. These power plants generate a high temperature flue gas by burning coal or other suitable fuel in a PFBC. The high temperature flue gas supports low-Btu fuel gas or natural gas combustion in a gas turbine topping combustor. When utilized, low-Btu fuel gas is produced in a bubbling bed carbonizer. High temperature, high pressure combustion products exiting the topping combustor are expanded in a modified gas turbine to generate electrical power. Waste heat from the system is used to generate and superheat steam for a reheat steam turbine bottoming cycle that generates additional electrical power. Basic control/instrumentation models were developed and modeled …
Date: December 31, 1996
Creator: White, J.S.; Bonk, D.L. & Rogers, L.
System: The UNT Digital Library
Advanced technologies for decontamination and conversion of scrap metal (open access)

Advanced technologies for decontamination and conversion of scrap metal

In October 1993, Manufacturing Sciences Corporation was awarded DOE contract DE-AC21-93MC30170 to develop and test recycling of radioactive scrap metal (RSM) to high value and intermediate and final product forms. This work was conducted to help solve the problems associated with decontamination and reuse of the diffusion plant barrier nickel and other radioactively contaminated scrap metals present in the diffusion plants. Options available for disposition of the nickel include decontamination and subsequent release or recycled product manufacture for restricted end use. Both of these options are evaluated during the course of this research effort. work during phase I of this project successfully demonstrated the ability to make stainless steel from barrier nickel feed. This paved the way for restricted end use products made from stainless steel. Also, after repeated trials and studies, the inducto-slag nickel decontamination process was eliminated as a suitable alternative. Electro-refining appeared to be a promising technology for decontamination of the diffusion plant barrier material. Goals for phase II included conducting experiments to facilitate the development of an electro-refining process to separate technetium from nickel. In parallel with those activities, phase II efforts were to include the development of the necessary processes to make useful products from …
Date: December 31, 1996
Creator: MacNair, V.; Muth, T.; Shasteen, K.; Liby, A.; Hradil, G. & Mishra, B.
System: The UNT Digital Library
Advancements in low NOx tangential firing systems (open access)

Advancements in low NOx tangential firing systems

The most cost effective method of reducing nitrogen oxide emissions when burning fossil fuels, such as coal, is through in-furnace NOx reduction processes. ABB Combustion Engineering, Inc. (ABB CE), through its ABB Power Plant Laboratories has been involved in the development of such low NOx pulverized coal firing systems for many years. This development effort is most recently demonstrated through ABB CE`s involvement with the U.S. Department of Energy`s (DOE) {open_quotes}Engineering Development of Advanced Coal Fired Low-Emission Boiler Systems{close_quotes} (LEBS) project. The goal of the DOE LEBS project is to use {open_quotes}near term{close_quotes} technologies to produce a commercially viable, low emissions boiler. This paper addresses one of the key technologies within this project, the NOx control subsystem. The foundation for the work undertaken at ABB CE is the TFS 2000{trademark} firing system, which is currently offered on a commercial basis. This system encompasses sub-stoichiometric combustion in the main firing zone for reduced NOx formation. Potential enhancements to this firing system focus on optimizing the introduction of the air and fuel within the primary windbox to provide additional horizontal and vertical staging. As is the case with all in-furnace NOx control processes, it is necessary to operate the system in a …
Date: December 31, 1996
Creator: Hein, R. von; Maney, C. & Borio, R.
System: The UNT Digital Library
Advances in nuclear instrumentation for safeguards (open access)

Advances in nuclear instrumentation for safeguards

This paper describes detectors, instrumentation, and analytical methods under development to address the above issues. The authors will describe work underway on room-temperature semiconductors including attempts to model the response of these detectors to improve spectrum analysis procedures and detector design. Computerized tomography is used in many medical and industrial applications; they are developing both gamma-ray and neutron tomography for improved measurements of waste and direct-use materials. Modern electronics and scintillation detectors should permit the development of fast neutron coincidence detectors with dramatically improved signal-to-noise ratios. For active measurements, they are studying several improved neutron sources, including a high-fluence, plasma-based, d-t generator. New analysis tools from information theory may permit one to better combine data from different measurement systems. This paper attempts to briefly describe a range of new sensors, electronics, and data analysis methods under study at Los Alamos and other laboratories to promote discussion of promising technology that they may bring to bear on these important global issues.
Date: December 31, 1996
Creator: Prettyman, T. H.; Reilly, T. D.; Miller, M. C.; Hollas, C. L.; Pickrell, M. M.; Prommel, J. M. et al.
System: The UNT Digital Library
AFBC - operation of small scale demonstration for greenhouse heating (open access)

AFBC - operation of small scale demonstration for greenhouse heating

A 2.2 million Btu/hr unit prototype AFBC system was installed in 1995 at Cedar Lane Farms, a commercial nursery in Ohio. The AFBC is in operation and is heating hot water for greenhouse temperature control. A team consisting of the Energy and Environmental Research Corporation, the Ohio Agricultural Research and Development Center of Ohio State University and the Will-Burt Company developed this technology with funding support from the Ohio Coal Development Office and the U.S. Department of Energy. The system is fully automated with little operator attention being required. Operating experience at Cedar Lane Farms has shown that only 2 hours per day of operation attention is required for the system. The system includes flyash/sorbent reinjection and underbed coal/limestone feed. These features provide for good limestone utilization; a Ca/S (in coal) ratio of 2.5 will maintain an SO{sub 2} emissions level of 1.2 lb/10{sup 6} Btu when burning high sulfur (3.2%) Ohio coal. A baghouse is used to control particulate emissions. Based on the success of the prototype unit, a design has been recently completed for a commercial size 10 x 10{sup 6} Btu/hr capacity range. Multiple AFBC units can be used to provide larger heat outputs. Potential coal-fired AFBC …
Date: December 31, 1996
Creator: Ashworth, Robert A.; Plessinger, Duane A.; Webner, Rodney L. & Machamer, Thomas
System: The UNT Digital Library
Alpha-emitters for medical therapy workshop (open access)

Alpha-emitters for medical therapy workshop

A workshop on ``Alpha-Emitters for Medical Therapy`` was held May 30-31, 1996 in Denver Colorado to identify research goals and potential clinical needs for applying alpha-particle emitters and to provide DOE with sufficient information for future planning. The workshop was attended by 36 participants representing radiooncology, nuclear medicine, immunotherapy, radiobiology, molecular biology, biochemistry, radiopharmaceutical chemistry, dosimetry, and physics. This report provides a summary of the key points and recommendations arrived at during the conference.
Date: December 31, 1996
Creator: Feinendegen, L.E. & McClure, J.J.
System: The UNT Digital Library
American National Standard ANSI/ANS-8.15-1983: Nuclear criticality control of special actinide elements (open access)

American National Standard ANSI/ANS-8.15-1983: Nuclear criticality control of special actinide elements

The American National Standard, `Nuclear Criticality Safety in Operations with Fissionable Materials Outside Reactors` ANSI/ANS-8.1- 1983 provides guidance for the nuclides [sup 233]U, [sup 235]U, and [sup 239]Pu These three nuclides are of primary interest in out-of-reactor criticality safety since they are the most commonly encountered in the vast majority of operations. However, some operations can involve nuclides other than `U, `U, and `Pu in sufficient quantities that their effect on criticality safety could be of concern. The American National Standard, `Nuclear Criticality Control of Special Actinide Elements` ANSI/ANS-8.`15-1983 (Ref 2), provides guidance for fifteen such nuclides.
Date: December 31, 1996
Creator: Brewer, R. W.; Pruvost, N. L. & Rombough, C. T.
System: The UNT Digital Library
Americium/curium extraction from a lanthanide borosilciate glass (open access)

Americium/curium extraction from a lanthanide borosilciate glass

A solution containing kilogram quantities of highly radioactive isotopes of americium and curium (Am/Cm) and lanthanide fission products is currently stored in a process tank at the Department of Energy`s Savannah River Site (SRS). This tank and its vital support systems are old, subject to deterioration, and prone to possible leakage. For this reason, a program has been initiated to immobilize this material as a lanthanide borosilicate glass for safe long-term storage. The Am/Cm has commercial value and is desired for use by the heavy isotope programs at the Oak Ridge National Laboratory (ORNL). Therefore, a flowsheet was demonstrated using a curium-containing glass to extract these elements from the glass matrix. The method involved grinding the glass to less than 200 mesh and dissolving in concentrated nitric acid at 110{degrees}C. Under these conditions, the dissolution was essentially 100% after 2 hours except for silicon which remained mostly insoluble. Since the actual process conditions at ORNL could not be exactly simulated, the dissolution rate of a surrogate glass was measured using static and agitated conditions to bracket the expected rate. The measured rates, 0.040 to 0.0082 grams/hour-centimeter, were constant which allowed development of a predictive model for the time required to …
Date: December 31, 1996
Creator: Rudisill, T. S.; Pareizs, J. M. & Ramsey, W. G.
System: The UNT Digital Library
Anaerobic and aerobic transformation of TNT (open access)

Anaerobic and aerobic transformation of TNT

Most studies on the microbial metabolism of nitroaromatic compounds have used pure cultures of aerobic microorganisms. In many cases, attempts to degrade nitroaromatics under aerobic conditions by pure cultures result in no mineralization and only superficial modifications of the structure. However, mixed culture systems properly operated result in the transformation of 2,4,6-trinitrotoluene (TNT) and in some cases mineralization of TNT occurs. In this paper, the mixed culture system is described with emphasis on intermediates and the characteristics of the aerobic microbial process including the necessity for a co-substrate. The possibility of removing TNT under aerobic/anoxic conditions is described in detail. Another option for the biodegradation of TNT and nitroaromatics is under anaerobic, sulfate reducing conditions. In this instance, the nitroaromatic compounds undergo a series of reductions with the formation of amino compounds. TNT under sulfate reducing conditions is reduced to triaminotoluene presumably by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of nitro groups from TNT is achieved by a series of reductive reactions with the formation of ammonia and toluene by Desulfovibrio sp. (B strain). These metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. The …
Date: December 31, 1996
Creator: Kulpa, C.F.; Boopathy, R. & Manning, J.
System: The UNT Digital Library
Analyses of containment structures with corrosion damage (open access)

Analyses of containment structures with corrosion damage

Corrosion damage to a nuclear power plant containment structure can degrade the pressure capacity of the vessel. For the low-carbon, low- strength steels used in containments, the effect of corrosion on material properties is discussed. Strain-to-failure tests, in uniaxial tension, have been performed on corroded material samples. Results were used to select strain-based failure criteria for corroded steel. Using the ABAQUS finite element analysis code, the capacity of a typical PWR Ice Condenser containment with corrosion damage has been studied. Multiple analyses were performed with the locations of the corrosion the containment, and the amount of corrosion varied in each analysis.
Date: December 31, 1996
Creator: Cherry, J.L.
System: The UNT Digital Library
Analysis and design methodology for the development of optimized, direct-detection CO{sub 2} DIAL receivers (open access)

Analysis and design methodology for the development of optimized, direct-detection CO{sub 2} DIAL receivers

The analysis methodology and corresponding analytical tools for the design of optimized, low-noise, hard target return CO{sub 2} Differential Absorption Lidar (DIAL) receiver systems implementing both single element detectors and multi-pixel imaging arrays for passive/active, remote-sensing applications are presented. System parameters and components composing the receiver include: aperture, focal length, field of view, cold shield requirements, image plane dimensions, pixel dimensions, pixel pitch and fill factor, detection quantum efficiency, optical filter requirements, amplifier and temporal sampling parameters. The performance analysis is accomplished by calculating the system`s CO{sub 2} laser range response, total noise, optical geometric form factor and optical resolution. The noise components include speckle, photon noise due to signal, scene and atmospheric background, cold shield, and electronic noise. System resolution is simulated through cascaded optical transfer functions and includes effects due to atmosphere, optics, image sampling, and system motion. Experimental results of a developmental single-element detector receiver designed to detect 100 ns wide laser pulses (10 - 100 kHz pulse repetition rates) backscattered from hard-targets at nominal ranges of 10 km are presented. The receiver sensitivity is near-background noise limited, given an 8.5-11.5 {mu}m radiant optical bandwidth, with the total noise floor spectrally white for maximum pulse averaging efficiency.
Date: December 31, 1996
Creator: Cooke, B.J.; Laubscher, B.E. & Cafferty, M.
System: The UNT Digital Library
Analysis and performance of adjacent-cell preconditioners for accelerating multidimensional transport calculations (open access)

Analysis and performance of adjacent-cell preconditioners for accelerating multidimensional transport calculations

The formal development of the Adjacent-cell Preconditioner (AP) and its implementation in the TORT code are briefly reviewed. Based on earlier experience with diffusion type acceleration, and excellent results in slab geometry the reciprocal averaging formula is used to mix the preconditioner elements across material and mesh discontinuities. Numerical testing of the method employing the Burre Suite of Test Problems (BSTeP), a collection of 144 cases covering a wide range in parameter space, using AP, Partial Current Rebalance (PCR), and TWODANT`s Diffusion Synthetic Acceleration (DSA) is presented. While AP outperforms the other two methods for the majority of the cases included in BSTeP it consumes many more iterations than can be explained by spectral analysis of the homogeneous model problem in cases with sharp material discontinuity. In order to verify this undesirable behavior and explore potential remedies a model problem, the Periodic Horizontal Interface (PHI), is developed that permits discontinuity of nuclear properties and cell height across the interface. Fourier mode decomposition is applied to AP with the reciprocal averaging mixing formula for the PHI configuration and shown to possess a spectral radius that approaches unity as the material discontinuity gets larger. The question of whether an unconditionally stable AP …
Date: December 31, 1996
Creator: Azmy, Y.Y.
System: The UNT Digital Library