Adaptive Mesh Refinement in CTH (open access)

Adaptive Mesh Refinement in CTH

This paper reports progress on implementing a new capability of adaptive mesh refinement into the Eulerian multimaterial shock- physics code CTH. The adaptivity is block-based with refinement and unrefinement occurring in an isotropic 2:1 manner. The code is designed to run on serial, multiprocessor and massive parallel platforms. An approximate factor of three in memory and performance improvements over comparable resolution non-adaptive calculations has-been demonstrated for a number of problems.
Date: May 4, 1999
Creator: Crawford, David
Object Type: Article
System: The UNT Digital Library
Beam motions near separatrix (open access)

Beam motions near separatrix

Experimental data on particle motion near the separatrix of the one dimensional (1-D) fourth-integer islands are an-alyzed. When the beam bunch is initially kicked to the separatrix orbit, we observed a strong decoherence in the coherent betatron motion. We find that, through intensive particle tracking simulation analysis, the decoherence has resulted from the beam being split into beamlets in the beta-tron phase space. However, we also observe an unexpected recoherence of coherence signal, which may result form a modulated closed orbit or the homoclinic structure near the separatrix.
Date: May 4, 1999
Creator: al., M. Ball et
Object Type: Article
System: The UNT Digital Library
Beam test of a superconducting cavity for the Fermilab high-brightness electron photo-injector (open access)

Beam test of a superconducting cavity for the Fermilab high-brightness electron photo-injector

An electron photo-injector facility has been constructed at Fermilab for the purpose of providing a 14�18 MeV elec-tron beam with high charge per bunch (8 nC), short bunch length (1 mm RMS), and small transverse emittance [1]. The facility was used to commission a second-generation photo-cathode RF gun for the TeSLA Test Facility (TTF) Linac at DESY [2, 3]; in the future, the Fermilab electron beam will be used for R & D in bunch length compres-sion, beam diagnostics, and new acceleration techniques. Acceleration beyond 4 MeV is provided by a 9-cell super-conducting cavity (see Figure 1). The cavity also provides a longitudinal position-momentum correlation for subse-quent bunch length compression. We report on the RF tests and a first beam test of this cavity.
Date: May 4, 1999
Creator: W. Hartung, J.P. Carneiro, M. Champion, H. Edwards, J. Fuest, K. Koepke and M. Kuchnir
Object Type: Article
System: The UNT Digital Library
Capacitor mismatch caused by oxide thickness variations in submicron I. C. processes (open access)

Capacitor mismatch caused by oxide thickness variations in submicron I. C. processes

Chip design in submicron processes will present new challenges and problems which were not present in designs with larger dimension processes. One effect in the newer processes is the field oxide thickness variation due to interconnect density variations. This effect becomes much more extreme for the smaller dimension processes. Large density discontinuities can cause lower yield and will also result in capacitor value mismatch over substantial distances from the edges of a large array when using poly/metal capacitors. If good matching in this type of large area capacitor array is required, the only way to achieve this is to guarantee nearly constant metal/ poly density for at least 1500 microns (this distance will likely depend on the process) around the edges of the array. If the array boundary is close to the chip edge, then dummy capacitors should be placed up to the chip edge, and another layout with similar density must be placed as close as possible to the relevant edges of the chip in the reticle. When using a standard MOSIS reticle size, this may entail placing dummy chip layouts around the chips of interest in order to guarantee that identical density exists for the required distance outside …
Date: May 4, 1999
Creator: Zimmerman, Tom
Object Type: Report
System: The UNT Digital Library
Degradation Reactions in SONY-Type Li-Ion Batteries (open access)

Degradation Reactions in SONY-Type Li-Ion Batteries

Thermal instabilities were identified in SONY-type lithium-ion cells and correlated with interactions of cell constituents and reaction products. Three temperature regions of interaction were identified and associated with the state of charge (degree of Li intercalation) of the cell. Anodes were shown to undergo exothermic reactions as low as 100&deg;C involving the solid electrolyte interface (SEI) layer and the LiPF<sub>6</sub> salt in the electrolyte (EC: PC: DEC/LiPF<sub>6</sub>). These reactions could account for the thermal runaway observed in these cells beginning at 100&deg;C. Exothermic reactions were also observed in the 200&deg;C-300&deg;C region between the intercalated lithium anodes, the LiPF<sub>6</sub> salt and the PVDF. These reactions were followed by a high- temperature reaction region, 300&deg;C-400&deg;C, also involving the PVDF binder and the intercalated lithium anodes. The solvent was not directly involved in these reactions but served as a moderator and transport medhun. Cathode exotherrnic reactions with the PVDF binder were observed above 200oC and increased with the state of charge (decreasing Li content). This offers an explanation for the observed lower thermal runaway temperatures for charged cells.
Date: May 4, 1999
Creator: Nagasubramanian, G. & Roth, E. Peter
Object Type: Article
System: The UNT Digital Library
Department of Defense: Status of Financial Management Weaknesses and Actions Needed to Correct Continuing Challenges (open access)

Department of Defense: Status of Financial Management Weaknesses and Actions Needed to Correct Continuing Challenges

Testimony issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed the status of financial management at the Department of Defense (DOD), focusing on: (1) DOD's most serious financial management weaknesses; (2) the resulting impact on DOD's ability to effectively carry out its programs and operations; and (3) DOD's efforts to address these deficiencies."
Date: May 4, 1999
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Department of Health and Human Services, Administration for Children and Families: Temporary Assistance for Needy Families Program (open access)

Department of Health and Human Services, Administration for Children and Families: Temporary Assistance for Needy Families Program

Other written product issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO reviewed the Administration for Children and Families' (ACF) new rule on the Temporary Assistance for Needy Families (TANF) program. GAO noted that: (1) the rule contains key provisions of the new welfare block grant program enacted in 1996 by the Personal Responsibility and Work Opportunity Reconciliation Act of 1996 and the TANF program; (2) this program replaces the Aid to Families with Dependent Children program and the related programs known as the Job Opportunities and Basic Skills Training Program and the Emergency Assistance program; and (3) ACF complied with the applicable requirements in promulgating the rule."
Date: May 4, 1999
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Enzymology of the Pathway for Acetate Conversion to Methane in Methanosarcina thermophilia (open access)

Enzymology of the Pathway for Acetate Conversion to Methane in Methanosarcina thermophilia

These topics are covered: Regulation of enzyme synthesis; Activation of acetate to acetyl-CoA; Biochemistry of acetyl-CoA cleavage; Electron transport; Other enzymes implicated in the pathway of acetate conversion to methane; and publications resulting from this work.
Date: May 4, 1999
Creator: Ferry, James G.
Object Type: Report
System: The UNT Digital Library
Equal Employment Opportunity: Data Shortcomings Hinder Assessment of Conflicts in the Federal Workplace (open access)

Equal Employment Opportunity: Data Shortcomings Hinder Assessment of Conflicts in the Federal Workplace

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on the nature and extent of workplace conflicts that underlie the rising number of discrimination cases, focusing on: (1) the statutory bases (e.g., race, sex, or disability discrimination) under which employees filed complaints; (2) the kinds of issues (e.g., nonselection for promotion, harassment) that were cited in these complaints; and (3) why the data collected and reported by the Equal Employment Opportunity Commission (EEOC) were not helpful in answering the questions raised."
Date: May 4, 1999
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Evaluation of Aerogel Materials for High-Temperature Batteries (open access)

Evaluation of Aerogel Materials for High-Temperature Batteries

Siiica aerogels have 1/3 the thermal conductivity of the best commercial composite insulations, or ~13 mW/m-K at 25&deg;C. However, aerogels are transparent in the near IR region of 4-7 &micro;m, which is where the radiation peak from a thermal-battery stack occurs. Titania and carbon- black powders were examined as thermal opacifiers, to reduce radiation at temperatures between 300&deg;C and 600&deg;C, which spans the range of operating temperature for most thermal batteries. The effectiveness of the various opacifiers depended on the loading, with the best overall results being obtained using aerogels filled with carbon black. Fabrication and strength issues still remain, however.
Date: May 4, 1999
Creator: Ashley, Carol S.; Guidotti, Ronald A.; Reed, Scott T. & Reinhardt, Frederick W.
Object Type: Article
System: The UNT Digital Library
Evaluation of Human Performance Issues for Fire Risk (open access)

Evaluation of Human Performance Issues for Fire Risk

This paper summarizes the current status of the treatment of human reliability in fire risk analyses for nuclear power plants and identifies areas that need to be addressed. A new approach is suggested to improve the modeling.
Date: May 4, 1999
Creator: Bley, Dennis C.; Cooper, Susan E.; Forester, John A.; Kolaczkowski, Alan M.; Ramey-Smith, Ann; Thompson, Catherine M. et al.
Object Type: Article
System: The UNT Digital Library
Final report to the Department of Energy on DE-FG05-91ER40620: Electromagnetic studies of mesons, nucleons, and nuclei (open access)

Final report to the Department of Energy on DE-FG05-91ER40620: Electromagnetic studies of mesons, nucleons, and nuclei

None
Date: May 4, 1999
Creator: Baker, O. K.
Object Type: Report
System: The UNT Digital Library
High flux ceramic membrane for hydrogen separation. Final technical progress report (open access)

High flux ceramic membrane for hydrogen separation. Final technical progress report

Fuel cells that convert hydrogen to electricity will play an increasingly important role in the generation of future electric power for stationary and transportation sector applications. However, more economic methods to produce hydrogen from fossil fuels are needed. This project addresses the need to develop low cost ceramic membranes for hydrogen separation from reformed fuels.
Date: May 4, 1999
Creator: Durai-Swamy, K.
Object Type: Report
System: The UNT Digital Library
International petroleum statistics report, April 1999 (open access)

International petroleum statistics report, April 1999

The International Petroleum Statistics Report presents data on international oil production, demand, imports, and stocks. The report has four sections. Section 1 contains time series data on world oil production, and on oil demand and stocks in the Organization for Economic Cooperation and Development (OECD). This section contains annual data beginning in 1985, and monthly data for the most recent two years. Section 2 presents an oil supply/demand balance fore the world. This balance is presented in quarterly intervals for the most recent two years. Section 3 presents data on oil imports by OECD countries. This section contains annual data for the most recent year, quarterly data for the most recent two quarters, and monthly data for the most recent twelve months. Section 4 presents annual time series data on world oil production and oil stocks, demand, and trade in OECD countries. World oil production and OECD demand data are for the years 1970 through 1997; OECD stocks from 1973 through 1997; and OECD trade from 1987 through 1997. 4 figs., 48 tabs.
Date: May 4, 1999
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Isotopic investigation of recharge to a regional groundwater flow system, Great Basin, NV (open access)

Isotopic investigation of recharge to a regional groundwater flow system, Great Basin, NV

Groundwater recharge processes were investigated in central Nevada by examining the relationships between the stable isotope ({delta}D and {delta}{sup 18}O) compositions of snowfall, snowmelt, alpine spring waters, and regional groundwaters. Snowmelt infiltration is inferred to he the dominant source of groundwater recharge in this region. Bulk snow cores collected throughout central Nevada near the time of maximum accumulation have {delta}D and {delta}{sup 18}O pairs that plot subparallel to the global meteoric water line (GMWL), but have negative d-values, implying kinetic isotope enrichments. Heavy isotope enrichments occur at the base of snowpacks due to fractionation during snow metamorphism, sometimes resulting in remarkably systematic isotopic variations. Ice crystals in the soil immediately beneath the snowpack can be strongly depleted in heavy isotopes relative to the overlying snow, implying fractionation or exchange with the snowpack. Late season ablation processes tend to homogenize isotopic variations between snowpack layers, and cause the bulk isotopic composition of the snowpack to become enriched in {sup 18}O by 2-3{per_thousand} relative to the composition during peak accumulation. The dynamic evolution of the snowpack and snowmelt isotopic compositions over time makes it difficult to directly ascertain groundwater recharge compositions without careful mass balance measurements. Preliminary evidence suggests that small local …
Date: May 4, 1999
Creator: Criss, R E; Davisson, M L; Rose, T & Smith, D K
Object Type: Article
System: The UNT Digital Library
Medicare Subvention Demonstration: DOD Experience and Lessons for Possible VA Demonstration (open access)

Medicare Subvention Demonstration: DOD Experience and Lessons for Possible VA Demonstration

Testimony issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed the Department of Defense's (DOD) Medicare subvention demonstration program, focusing on: (1) the early phases of implementing the DOD demonstration; (2) issues raised by that experience for DOD subvention; and (3) lessons from the DOD demonstration for a possible Department of Veterans Affairs (VA) demonstration."
Date: May 4, 1999
Creator: United States. General Accounting Office.
Object Type: Text
System: The UNT Digital Library
Notice of construction for tank waste remediation system vadose zone characterization (open access)

Notice of construction for tank waste remediation system vadose zone characterization

The following description and any attachments and references are provided to the Washington State Department of Health (WDOH), Division of Radiation Protection, Air Emissions & Defense Waste Section as a notice of constriction (NOC) in accordance with Washington Administrative Code (WAC) 246-247, Radiation Protection - Air Emissions. The WAC 246-247-060, ''Applications, registration, and licensing'', states ''This section describes the information requirements for approval to construct, modify, and operate an emission unit. Any NOC requires the submittal of information listed in Appendix A.'' Appendix A (WAC 246-247-1 10) lists the requirements that must be addressed. Additionally, the following description, attachments and references are provided to the U.S. Environmental Protection Agency (EPA) as an NOC, in accordance with Title 40 Code of Federal Regulations (CFR), Part 61, ''National Emission Standards for Hazardous Air Pollutants.'' The information required for submittal to the EPA is specified in 40 CFR 61.07. The potential emissions from this activity are estimated to provide less than 0.1 millirem/year total effective dose equivalent (TEDE) to the hypothetical offsite maximally exposed individual (MEI), and commencement is needed within a short time frame. Therefore, this application is also intended to provide notification of the anticipated date of initial startup in accordance …
Date: May 4, 1999
Creator: HILL, J.S.
Object Type: Report
System: The UNT Digital Library
Nuclear Storage Facility Inventory and Information Management using the GraFIC Software. (open access)

Nuclear Storage Facility Inventory and Information Management using the GraFIC Software.

Oak Ridge has developed an intelligent facility and information management system to provide near real time, verifiable status of safeguarded materials in a nuclear storage facility. The Graphical Facility Information System (GraFIC{trademark}) is a versatile software package designed to operate in a distributed computing environment. GraFIC{trademark} is integrated with a suite of rugged, low-cost sensors that remotely monitor the physical and/or assigned attributes associated with stored nuclear materials and reports item and facility activity to an unlimited number of authorized clients. The software also contains facility management tools to assist with space planning, record management, item location, and a variety of other facilities needs.
Date: May 4, 1999
Creator: Hickerson, T.W.
Object Type: Article
System: The UNT Digital Library
Photocharge Transport and Recombination Measurements in Amorphous Silicon Films and Solar Cells by Photoconductive Frequency Mixing: Final Subcontract Report: 13 May 1994 - 15 January 1998 (open access)

Photocharge Transport and Recombination Measurements in Amorphous Silicon Films and Solar Cells by Photoconductive Frequency Mixing: Final Subcontract Report: 13 May 1994 - 15 January 1998

This report describes work performed during this subcontract by the University of California. The photoconductivity, lifetime, and drift mobility of intrinsic hydrogenated amorphous silicon (a-Si:H), hydrogenated amorphous silicon carbide (a-SiC:H), and hydrogenated amorphous silicon germanium (a-SiGe:H) were determined using a photomixing technique in the as prepared and light-soaked states. In addition to the decay of the photoconductivity and electron lifetime, continuous decay of the electron drift mobility was found during the light-soaking process (Staebler-Wronski effect). Experimental data were fitted to a stretched exponential law. Different stretched-exponential parameters for photoconductivity, lifetime, and drift mobility were obtained, which indicates the production of defects with different generation kinetics upon light soaking. The transport properties of intrinsic a-Si:H samples (which were produced by the hot-wire technique at NREL at different substrate temperatures such that the hydrogen content ranged from &gt;10% to &lt;1%), were systematically studied. It was found that with increasing substrate temperature, the lifetime, the drift mobility, and the photoconductivity decreased, but the Urbach energy ({approx} 0.1 eV below the conduction band) increased. These results indicate that for the a-Si:H films with increasing deposition temperature, the density of positively charged, negatively charged, and neutral defects all show a tendency to increase, in agreement …
Date: May 4, 1999
Creator: Braunstein, R.; Tang, Y.; Dong, S.; Liebe, J.; Sun, G. & Kattwinkel, A. (University of California: Los Angeles, California)
Object Type: Report
System: The UNT Digital Library
The practical implementation of integrated safety management for nuclear safety analysis and fire hazards analysis documentation (open access)

The practical implementation of integrated safety management for nuclear safety analysis and fire hazards analysis documentation

In 1995 Mr. Joseph DiNunno of the Defense Nuclear Facilities Safety Board issued an approach to describe the concept of an integrated safety management program which incorporates hazard and safety analysis to address a multitude of hazards affecting the public, worker, property, and the environment. Since then the U S . Department of Energy (DOE) has adopted a policy to systematically integrate safety into management and work practices at all levels so that missions can be completed while protecting the public, worker, and the environment. While the DOE and its contractors possessed a variety of processes for analyzing fire hazards at a facility, activity, and job; the outcome and assumptions of these processes have not always been consistent for similar types of hazards within the safety analysis and the fire hazard analysis. Although the safety analysis and the fire hazard analysis are driven by different DOE Orders and requirements, these analyses should not be entirely independent and their preparation should be integrated to ensure consistency of assumptions, consequences, design considerations, and other controls. Under the DOE policy to implement an integrated safety management system, identification of hazards must be evaluated and agreed upon to ensure that the public. the workers. …
Date: May 4, 1999
Creator: COLLOPY, M.T.
Object Type: Article
System: The UNT Digital Library
Research on the Use of Robotics in Hazardous Environments at Sandia National Laboratories (open access)

Research on the Use of Robotics in Hazardous Environments at Sandia National Laboratories

Many hazardous material handling needs exist in remote unstructured environments. Currently these operations are accomplished using personnel in direct contact with the hazards. A safe and cost effective alternative to this approach is the use of intelligent robotic systems for safe handling, packaging, transport, and even excavation of hazardous materials. The Intelligent Systems and Robotics Center of Sandia National Laboratories has developed and deployed robotic technologies for use in hazardous environments, three of which have been deployed in DOE production facilities for handling of special nuclear materials. Other systems are currently under development for packaging special nuclear materials. This paper presents an overview of the research activities, including five delivered systems, at %ndia National Laboratories on the use of robotics in hazardous environments.
Date: May 4, 1999
Creator: Kwok, Kwan S.
Object Type: Article
System: The UNT Digital Library
Spectroscopic Confirmation of Uranium (VI)-Carbonato Adsorption Complexes on Hematite (open access)

Spectroscopic Confirmation of Uranium (VI)-Carbonato Adsorption Complexes on Hematite

Evaluating societal risks posed by uranium contamination from waste management facilities, mining sites, and heavy industry requires knowledge about uranium transport in groundwater, often the most significant pathway of exposure to humans. It has been proposed that uranium mobility in aquifers may be controlled by adsorption of U(VI)-carbonato complexes on oxide minerals. The existence of such complexes has not been demonstrated, and little is known about their compositions and reaction stoichiometries. We have used Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) and Extended X-ray Absorption Fine Structure (EXAFS) spectroscopies to probe the existence, structures, and compositions of FeO{sub surface}-U(VI)-carbonato complexes on hematite throughout the pH range of uranyl uptake under conditions relevant to aquifers. U(VI)-carbonato complexes were found to be the predominant adsorbed U(VI) species at all pH values examined, a much wider pH range than previously postulated based on analogy to aqueous U(VI)-carbonato complexes, which are trace constituents at pH &lt; 6. This result indicates the inadequacy of the common modeling assumption that the compositions and predominance of adsorbed species can be inferred from aqueous species. By extension, adsorbed carbonato complexes may be of major importance to the groundwater transport of similar actinide contaminants such as neptunium and plutonium.
Date: May 4, 1999
Creator: Bargar, John R
Object Type: Report
System: The UNT Digital Library
Sub-Picosecond Injection of Electrons from Excited [Ru (2,2'-bipy-4,4'-dicarboxy)2(SCN)2] into TiO2 Using Transient Mid-Infrared Spectroscopy (open access)

Sub-Picosecond Injection of Electrons from Excited [Ru (2,2'-bipy-4,4'-dicarboxy)2(SCN)2] into TiO2 Using Transient Mid-Infrared Spectroscopy

We have used femtosecond pump-probe spectroscopy to time resolve the injection of electrons into nanocrystalline TiO2 film electrodes under ambient conditions following photoexcitation of the adsorbed dye, [Ru(4,4'-dicarboxy-2,2'-bipyridine)2(NCS)2] (N3). Pumping at one of the metal-to-ligand charge transfer adsorption peaks and probing the absorption of electrons injected into the TiO2 conduction band at 1.52 {micro}m and in the range of 4.1 to 7.0 {micro}m, we have directly observed the arrival of the injected electrons. Our measurements indicate an instrument-limited {approx}50-fs upper limit on the electron injection time under ambient conditions in air. We have compared the infrared transient absorption for noninjecting (blank) systems consisting of N3 in ethanol and N3 adsorbed to films of nanocrystalline Al2O3 and ZrO2, and found no indication of electron injection at probe wavelengths in the mid-IR (4.1 to 7.0 {micro}m). At 1.52 {micro}m interferences exist in the observed transient adsorption signal for the blanks.
Date: May 4, 1999
Creator: Ellingson, R. J.; Asbury, J. B.; Ferrere, S.; Ghosh, H. N.; Sprague, J. R.; Lian, T. et al.
Object Type: Article
System: The UNT Digital Library
Tank Farm Contractor Operation and Utilization Plan [SEC 1 Thru 3] (open access)

Tank Farm Contractor Operation and Utilization Plan [SEC 1 Thru 3]

The Tank Waste Remediation System Operation and Utilization Plan updates the operating scenario and plans for the delivery of feed to BNFL Inc., retrieval of waste from single-shell tanks, and the overall process flowsheets for Phases I and II of the privatization of the Tank Waste Remediation System. The plans and flowsheets are updated with the most recent tank-by-tank inventory and sludge washing data. Sensitivity cases were run to evaluate the impact or benefits of proposed changes to the BNFL Inc. contract and to evaluate a risk-based SST retrieval strategy.
Date: May 4, 1999
Creator: KIRKBRIDE, R.A.
Object Type: Report
System: The UNT Digital Library