NUCLEAR WASTE GLASSES CONTINUOUS MELTING AND BULK VITRIFICAITON (open access)

NUCLEAR WASTE GLASSES CONTINUOUS MELTING AND BULK VITRIFICAITON

This contribution addresses various aspects of nuclear waste vitrification. Nuclear wastes have a variety of components and composition ranges. For each waste composition, the glass must be formulated to possess acceptable processing and product behavior defined in terms of physical and chemical properties that guarantee the glass can be easily made and resist environmental degradation. Glass formulation is facilitated by developing property-composition models, and the strategy of model development and application is reviewed. However, the large variability of waste compositions presents numerous additional challenges: insoluble solids and molten salts may segregate; foam may hinder heat transfer and slow down the process; molten salts may accumulate in container refractory walls; the glass on cooling may precipitate crystalline phases. These problems need targeted exploratory research. Examples of specific problems and their possible solutions are discussed.
Date: March 24, 2008
Creator: AA, KRUGER & PR, HRMA
Object Type: Article
System: The UNT Digital Library
Top quark physics (open access)

Top quark physics

The top quark, when it was finally discovered at Fermilab in 1995 completed the three-generation structure of the Standard Model (SM) and opened up the new field of top quark physics. Viewed as just another SM quark, the top quark appears to be a rather uninteresting species. Produced predominantly, in hadron-hadron collisions, through strong interactions, it decays rapidly without forming hadrons, and almost exclusively through the single mode t {r_arrow} Wb. The relevant CKM coupling V{sub tb} is already determined by the (three-generation) unitarity of the CKM matrix. Rare decays and CP violation are unmeasurable small in the SM. Yet the top quark is distinguished by its large mass, about 35 times larger than the mass of the next heavy quark, and intriguingly close to the scale of electroweak (EW) symmetry breaking. This unique property raises a number of interesting questions. Is the top quark mass generated by the Higgs mechanism as the SM predicts and is its mass related to the top-Higgs-Yukawa coupling? Or does it play an even more fundamental role in the EW symmetry breaking mechanism? If there are new particles lighter than the top quark, does the top quark decay into them? Could non-SM physics first …
Date: March 24, 2000
Creator: Ahmadov, A.; Azuelos, G.; Bauer, U.; Belyaev, A.; Berger, E. L.; Sullivan, Z. et al.
Object Type: Article
System: The UNT Digital Library
Fluorescence Rise Time Measurements for High Temperature Fluorescence-Based Thermometry (open access)

Fluorescence Rise Time Measurements for High Temperature Fluorescence-Based Thermometry

Certain ceramic-like phosphor materials exhibit bright fluorescence with a pronounced temperature dependence over a range which spans the cryogenic to 1700 C, depending on the specific phosphor. To measure temperature, a surface, for instance a turbine blade, is coated with the material. An optical system, sometimes including optical fibers, conveys stimulating light and collects the emission for analysis. Either emission intensity or decay time may indicate temperature. Previously fielded tests have involved surfaces such as blades, vanes, pistons, in-take valves, sheets of galvanneal steel, etc. The fluorescent coatings may be applied to small parts via sputtering methods or to large areas by mixture with inorganic binders. Presented here are results characterizing fluorescence rise times as a means of determining temperature from ambient to 700 C for Y{sub 2}O{sub 3}:Eu.
Date: March 24, 2005
Creator: Allison, S.W.
Object Type: Report
System: The UNT Digital Library
Design and Status of the Visa II Experiment. (open access)

Design and Status of the Visa II Experiment.

VISA II is the follow-up project to the successful Visible to Infrared SASE Amplifier (VISA) experiment at the Accelerator Test Facility (ATF) in Brookhaven National Lab (BNL). This paper will report the motivation for and status of the two main experiments associated with the VISA II program. One goal of VISA II is to perform an experimental study of the physics of a chirped beam SASE FEL at the upgraded facilities of the ATF. This requires a linearization of the transport line to preserve energy chirping of the electron beam at injection. The other planned project is a strong bunch compression experiment, where the electron bunch is compressed in the chicane, and the dispersive beamline transport, allowing studies of deep saturation.
Date: March 24, 2004
Creator: Andonian, G.
Object Type: Article
System: The UNT Digital Library

Colorado New Energy Summit

Presentation by Dr. Dan Arvizu of NREL given at the Colorado New Energy Summit held March 24, 2007 in Denver, Colorado.
Date: March 24, 2007
Creator: Arvizu, D. E.
Object Type: Presentation
System: The UNT Digital Library
Nonlinear self-duality in even dimensions (open access)

Nonlinear self-duality in even dimensions

We show that the Born-Infeld theory with n complex abelian gauge fields written in an auxiliary field formulation has a U(n, n) duality group. We conjecture the form of the Lagrangian obtained by eliminating the auxiliary fields and then introduce a new reality structure leading to a Born-Infeld theory with n real gauge fields and an Sp(2n, IR) duality symmetry. The real and complex constructions are extended to arbitrary even dimensions. The maximal noncompact duality group is U(n, n) for complex fields. For real fields the duality group is Sp(2n, IR) if half of the dimension of space-time is even and O(n, n) if it is odd. We also discuss duality under the maximal compact subgroup, which is the self-duality group of the theory obtained by fixing the expectation value of a scalar field. Supersymmetric versions of self-dual theories in four dimensions are also discussed.
Date: March 24, 2000
Creator: Aschieri, Paolo; Brace, Daniel; Morariu, Bogdan & Zumino, Bruno
Object Type: Article
System: The UNT Digital Library
Atmospheric Radiation Measurement Program Facilities Newsletter, February 2000 (open access)

Atmospheric Radiation Measurement Program Facilities Newsletter, February 2000

Monthly newsletter discussing news and activities related to the Atmospheric Radiation Measurement Program, articles about weather and atmospheric phenomena, and other related topics.
Date: March 24, 2000
Creator: Atmospheric Radiation Measurement Program (U.S.)
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
Measurement of the tau- to eta pi-pi+pi-nu tau Branching Fraction and a Search for a Second-Class Current in the tau- to eta'(958)pi-nu tau Decay (open access)

Measurement of the tau- to eta pi-pi+pi-nu tau Branching Fraction and a Search for a Second-Class Current in the tau- to eta'(958)pi-nu tau Decay

The {tau}{sup -} {yields} {eta}{pi}{sup -}{pi}{sup +}{pi}{sup -}{nu}{sub {tau}} decay with the {eta} {yields} {gamma}{gamma} mode is studied using 384 fb{sup -1} of data collected by the BABAR detector. The branching fraction is measured to be (1.60 {+-} 0.05 {+-} 0.11) x 10{sup -4}. It is found that {tau}{sup -} {yields} f{sub 1}(1285){pi}{sup -} {nu}{sub {tau}} {yields} {eta}{pi}{sup -}{pi}{sup +}{pi}{sup -}{nu}{sub {tau}} is the dominant decay mode with a branching fraction of (1.11 {+-} 0.06 {+-} 0.05) x 10{sup -4}. The first error on the branching fractions is statistical and the second systematic. In addition, a 90% confidence level upper limit on the branching fraction of the {tau}{sup -} {yields} {eta}{prime}(958){pi}{sup -}{nu}{sub {tau}} decay is measured to be 7.2 x 10{sup -6}. This last decay proceeds through a second-class current and is expected to be forbidden in the limit of isospin symmetry.
Date: March 24, 2008
Creator: Aubert, B.; Bona, M.; Boutigny, D.; Karyotakis, Y.; Lees, J. P.; Poireau, V. et al.
Object Type: Article
System: The UNT Digital Library
Requirements Analysis Study for Master Pump Shutdown System Project Development Specification [SEC 1 and 2] (open access)

Requirements Analysis Study for Master Pump Shutdown System Project Development Specification [SEC 1 and 2]

This document has been updated during the definitive design portion of the first phase of the W-314 Project to capture additional software requirements and is planned to be updated during the second phase of the W-314 Project to cover the second phase of the Project's scope. The objective is to provide requirement traceability by recording the analysis/basis for the functional descriptions of the master pump shutdown system. This document identifies the sources of the requirements and/or how these were derived. Each requirement is validated either by quoting the source or an analysis process involving the required functionality, performance characteristics, operations input or engineering judgment.
Date: March 24, 2000
Creator: BEVINS, R.R.
Object Type: Report
System: The UNT Digital Library
Actinic inspection of multilayer defects on EUV masks (open access)

Actinic inspection of multilayer defects on EUV masks

The production of defect-free mask blanks, and the development of techniques for inspecting and qualifying EUV mask blanks, remains a key challenge for EUV lithography. In order to ensure a reliable supply of defect-free mask blanks, it is necessary to develop techniques to reliably and accurately detect defects on un-patterned mask blanks. These inspection tools must be able to accurately detect all critical defects whilst simultaneously having the minimum possible false-positive detection rate. There continues to be improvement in high-speed non-actinic mask blank inspection tools, and it is anticipated that these tools can and will be used by industry to qualify EUV mask blanks. However, the outstanding question remains one of validating that non-actinic inspection techniques are capable of detecting all printable EUV defects. To qualify the performance of non-actinic inspection tools, a unique dual-mode EUV mask inspection system has been installed at the Advanced Light Source (ALS) synchrotron at Lawrence Berkeley National Laboratory. In high-speed inspection mode, whole mask blanks are scanned for defects using 13.5-nm wavelength light to identify and map all locations on the mask that scatter a significant amount of EUV light. In imaging, or defect review mode, a zone plate is placed in the reflected …
Date: March 24, 2005
Creator: Barty, A.; Liu, Y.; Gullikson, E.; Taylor, J. S. & Wood, O.
Object Type: Article
System: The UNT Digital Library
Mad Cow Disease: Agricultural Issues for Congress (open access)

Mad Cow Disease: Agricultural Issues for Congress

This report provides information on how most of the countries banned United States beef after the first report of Bovine Spongiform Encephalopathy (BSE) in a Canadian-born cow after the December 2003 U.S. report. This explains all the steps USDA has taken to reduce the positive cases of BSE by starting special programs. Updated March 24, 2005.
Date: March 24, 2005
Creator: Becker, Geoffrey S.
Object Type: Report
System: The UNT Digital Library
Fuel Transformer Solid Oxide Fuel Cell Progress Report (open access)

Fuel Transformer Solid Oxide Fuel Cell Progress Report

The following report documents the technical approach and conclusions made by Acumentrics Corporation during latest budget period toward the development of a low cost 10kW tubular SOFC power system. The present program, guided under direction from the National Energy Technology Laboratory of the US DOE, is a nine-year cost shared Cooperative Agreement totaling close to $74M funded both by the US DOE as well as Acumentrics Corporation and its partners. The latest budget period ran from July of 2004 through January 2004. Work was focused on cell technology enhancements as well as BOP and power electronics improvements and overall system design. Significant progress was made in increasing cell power enhancements as well as decreasing material cost in a drive to meet the SECA cost targets. The following report documents these accomplishments in detail as well as the lay out plans for further progress in next budget period.
Date: March 24, 2005
Creator: Bessette, Norman; Schmidt, Douglas S.; Rawson, Jolyon; Allfather, Lars & Litka, Anthony
Object Type: Report
System: The UNT Digital Library
Soil Stabilization and Revegetation at the INEEL Recommendations for Improvement (open access)

Soil Stabilization and Revegetation at the INEEL Recommendations for Improvement

Soil stabilization for the INEEL Stormwater Pollution Prevention Plan (SWPPP) has mostly been by revegetation, but has experienced only limited success. The purpose of this report is to discuss issues associated with revegetation failures and to explore possible remedies.
Date: March 24, 2003
Creator: Blew, R. D.; Jackson, M. R. & Forman, A. D.
Object Type: Report
System: The UNT Digital Library
An Overview of the Administration's Strengthening America's Communities Initiative (open access)

An Overview of the Administration's Strengthening America's Communities Initiative

This report discusses administration’s proposed base program called strengthening America’s communities initiative intended to award funds in support of job creation and economic development.
Date: March 24, 2005
Creator: Boyd, Eugene; Mulock, Bruce K.; Smale, Pauline; Cowan, Tadlock; Laney, Garrine P. & Foote, Bruce E.
Object Type: Report
System: The UNT Digital Library
The development of a ductility-based aging model for low temperature aged U-6Nb alloy (open access)

The development of a ductility-based aging model for low temperature aged U-6Nb alloy

This study focuses on the ductility evaluation of low-temperature (100 and 200 C) aged U-6Nb alloy. The objective is to develop a ductility-based aging model to improve lifetime prediction for weapon components in the stockpile environment. Literature review shows that the work hardening n-value and the strain-rate hardening mvalue are the two most important metallurgical factors for the uniform and the post-uniform (necking) ductility control, respectively. Unfortunately, both n and m values of the U-6Nb alloy are lacking. The study shows that the total ductility of U-6Nb is dominated by the uniform ductility, which deteriorates in both 100 C and 200 C aging. Further analysis shows that the uniform ductility correlates well with the work hardening n-value of the later stage deformation in which dislocation-slip is the mechanism. The kinetics of the loss of uniform ductility and the associated reduction in work-hardening n-value in low temperature aging will be used for the development of a ductility-based aging model. The necking ductility appears to be a minor but significant factor in the total ductility of U-6Nb. It does not show a clear trend due to large data scatter. The uncertain nature of necking failure may always hinder a reliable measurement of …
Date: March 24, 2005
Creator: Bridges, B
Object Type: Article
System: The UNT Digital Library
Uncertainty Quantification Approaches for Advanced Reactor Analyses. (open access)

Uncertainty Quantification Approaches for Advanced Reactor Analyses.

The original approach to nuclear reactor design or safety analyses was to make very conservative modeling assumptions so as to ensure meeting the required safety margins. Traditional regulation, as established by the U. S. Nuclear Regulatory Commission required conservatisms which have subsequently been shown to be excessive. The commission has therefore moved away from excessively conservative evaluations and has determined best-estimate calculations to be an acceptable alternative to conservative models, provided the best-estimate results are accompanied by an uncertainty evaluation which can demonstrate that, when a set of analysis cases which statistically account for uncertainties of all types are generated, there is a 95% probability that at least 95% of the cases meet the safety margins. To date, nearly all published work addressing uncertainty evaluations of nuclear power plant calculations has focused on light water reactors and on large-break loss-of-coolant accident (LBLOCA) analyses. However, there is nothing in the uncertainty evaluation methodologies that is limited to a specific type of reactor or to specific types of plant scenarios. These same methodologies can be equally well applied to analyses for high-temperature gas-cooled reactors and to liquid metal reactors, and they can be applied to steady-state calculations, operational transients, or severe accident …
Date: March 24, 2009
Creator: Briggs, L. L.
Object Type: Report
System: The UNT Digital Library
Final Report for Department of Energy Grant DE-FG02-97ER45666 ?Interface Diffusion and Deep Level Formation of SiC and Other Wide Gap Materials? (open access)

Final Report for Department of Energy Grant DE-FG02-97ER45666 ?Interface Diffusion and Deep Level Formation of SiC and Other Wide Gap Materials?

This final report describes the research effort focusing on the nature of charge transfer and localized electronic structure at semiconductor interfaces, one of the most fundamental issues in the solid state. The basic charge exchange between two materials in general is directly connected with the systematic atomic bonding changes and redistribution that occurs at the nanoscale interface. Our programhas extended our understanding of the atomic-scale nature of electrostatic barrier formation, heterojunction band offsets, and the optical and electronic features of impurity confinement in a set of model materials systems, including nanometer-scale wide band gap semiconductor and insulator structures. This fundamentally new class of materials investigation utilizes a powerful and unique combination of techniques that are revealing the atomic-scale movement, chemical bonding, and resultant charge transfer across well-defined model interfaces.
Date: March 24, 2006
Creator: Brillson, Leonard J.
Object Type: Report
System: The UNT Digital Library
QA Objectives for Nondestructive Assay at the Waste Receiving and Processing (WRAP) Facility (open access)

QA Objectives for Nondestructive Assay at the Waste Receiving and Processing (WRAP) Facility

The Waste Receiving and Processing (WRAP) facility, located on the Hanford Site in southeast Washington, is a key link in the certification of transuranic (TRU) waste for shipment to the Waste Isolation Pilot Plant (WIPP). Waste characterization is one of the vital functions performed at WRAP, and nondestructive assay (NDA) measurements of TRU waste containers is one of two required methods used for waste characterization. The Waste Acceptance Criteria for the Waste Isolation Pilot Plant, DOEMPP-069 (WIPP-WAC) delineates the quality assurance objectives which have been established for NDA measurement systems. Sites must demonstrate that the quality assurance objectives can be achieved for each radioassay system over the applicable ranges of measurement. This report summarizes the validation of the WRAP NDA systems against the radioassay quality assurance objectives or QAOs. A brief description of the each test and significant conclusions are included. Variables that may have affected test outcomes and system response are also addressed.
Date: March 24, 2000
Creator: CANTALOUB, M.G. & WILLS, C.E.
Object Type: Report
System: The UNT Digital Library
A coupled Newton-Krylov solver for improved CHAD cache utilization and performance. (open access)

A coupled Newton-Krylov solver for improved CHAD cache utilization and performance.

CHAD (Computational Hydrodynamics for Advanced Design) is a computer program that has been developed to analyze flows in automotive and defense applications. Extensive performance analysis of the CHAD computer program indicated a need to address cache memory use to increase computational performance. Several strategies have been adopted to achieve this goal: simultaneous solution of the coupled Navier-Stokes equations, data clustering, and data ordering. A coupled Newton-Krylov solver has been incorporated into a version of the CHAD program, resulting in consistent improvement in run times that varies from 50% to 200%. Further work will be required to tune the solver for optimal performance. In addition, experiments with data cluster and reordering indicate a potential for performance improvement.
Date: March 24, 2000
Creator: Canfield, T.R.; Chien, T. H.; Domanus, H. M.; Tentner, A. M.; Tzanos, C. P.; Valentin, R. A. et al.
Object Type: Article
System: The UNT Digital Library
How far from stability can we go using Gammasphere and the ANL fragment mass analyzer? (open access)

How far from stability can we go using Gammasphere and the ANL fragment mass analyzer?

Gammasphere is the pre-eminent detector for gamma-ray spectroscopy studies in the United States. The device consists of up to 110 Compton-Suppressed Ge detectors, and offers excellent energy resolution (2.3 keV at 1 MeV) and an order of magnitude increase in photopeak efficiency over previous Ge-arrays (10% at 1 MeV). Since early January 1998, Gammasphere has begun a cycle of experiments at the ATLAS accelerator at Argonne National Laboratory. As of this writing, 100 experiments have been carried out. A subset of these experiments have utilized Gammasphere coupled to the Fragment Mass Analyzer (FMA), a high resolution mass spectrometer which transports reaction products produced at the target position and disperses them by their mass/charge ratio at the focal plane. This presentation will highlight some of the physics issues being addressed by the utilization of these two devices in tandem. More specifically, experiments directed at studying; (1) N-Z nuclei at the edges of stability, (2) the properties of excited states in proton emitters, and (3) the stability and shapes of very heavy nuclei will be presented.
Date: March 24, 2000
Creator: Carpenter, M. P.
Object Type: Article
System: The UNT Digital Library
Narrow linewidth intervalence-band emission from germanium THz lasers (open access)

Narrow linewidth intervalence-band emission from germanium THz lasers

None
Date: March 24, 2003
Creator: Chamberlin, D.R.; Brundermann, E. & Haller, E.E.
Object Type: Article
System: The UNT Digital Library
HB-Line Special Nuclear Material Campaigns: Model-Based Project Management (open access)

HB-Line Special Nuclear Material Campaigns: Model-Based Project Management

This study is to show how a model was used to enable management to better estimate production capabilities to ensure contract milestones/commitments are met, to cope with fast changing project baselines and project missions, to ensure the project will meet the negotiated throughput, and to eliminate unnecessary but costly design changes.
Date: March 24, 2004
Creator: Chang, Robert
Object Type: Article
System: The UNT Digital Library
A Graph Search Heuristic for Shortest Distance Paths (open access)

A Graph Search Heuristic for Shortest Distance Paths

This paper presents a heuristic for guiding A* search for finding the shortest distance path between two vertices in a connected, undirected, and explicitly stored graph. The heuristic requires a small amount of data to be stored at each vertex. The heuristic has application to quickly detecting relationships between two vertices in a large information or knowledge network. We compare the performance of this heuristic with breadth-first search on graphs with various topological properties. The results show that one or more orders of magnitude improvement in the number of vertices expanded is possible for large graphs, including Poisson random graphs.
Date: March 24, 2005
Creator: Chow, E
Object Type: Article
System: The UNT Digital Library
Formulation and Performance of Novel Energetic Nanocomposites and Gas Generators Prepared by Sol-Gel Methods (open access)

Formulation and Performance of Novel Energetic Nanocomposites and Gas Generators Prepared by Sol-Gel Methods

In the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing nanostructured metal oxide materials. By introducing a fuel metal, such as aluminum, into the nanostructured metal oxide matrix, energetic materials based on thermite reactions can be fabricated. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. Due to the versatility of the preparation method, binary oxidizing phases can also be prepared, thus enabling a potential means of controlling the energetic properties of the subsequent nanocomposites. Furthermore, organic additives can also be easily introduced into the nanocomposites for the production of nanostructured gas generators. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its micro-scale counterparts due to the expected increase of mass transport …
Date: March 24, 2005
Creator: Clapsaddle, B. J.; Zhao, L.; Prentice, D.; Pantoya, M. L.; Gash, A. E.; Satcher J. H. Jr. et al.
Object Type: Article
System: The UNT Digital Library