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
System: The UNT Digital Library
On the occasion of the inauguration of Balenciaga and His Legacy: Haute Couture from the Texas Fashion Collection (open access)

On the occasion of the inauguration of Balenciaga and His Legacy: Haute Couture from the Texas Fashion Collection

Article and gallery of photographs from the gala premiere for the "Balenciaga and His Legacy: Haute Couture from the Texas Fashion Collection" exhibit held at the Meadows Museum in Dallas.
Date: March 24, 2007
Creator: Adams, Sharon
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.
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.
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
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.
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.
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
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.
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.
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

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Date: March 24, 2003
Creator: Chamberlin, D.R.; Brundermann, E. & Haller, E.E.
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
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
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.
System: The UNT Digital Library
Harnessing microbial subsurface metal reduction activities to synthesise nanoscale cobalt ferrite with enhanced magnetic properties (open access)

Harnessing microbial subsurface metal reduction activities to synthesise nanoscale cobalt ferrite with enhanced magnetic properties

Nanoscale ferrimagnetic particles have a diverse range of uses from directed cancer therapy and drug delivery systems to magnetic recording media and transducers. Such applications require the production of monodisperse nanoparticles with well-controlled size, composition, and magnetic properties. To fabricate these materials purely using synthetic methods is costly in both environmental and economical terms. However, metal-reducing microorganisms offer an untapped resource to produce these materials. Here, the Fe(III)-reducing bacterium Geobacter sulfurreducens is used to synthesize magnetic iron oxide nanoparticles. A combination of electron microscopy, soft X-ray spectroscopy, and magnetometry techniques was employed to show that this method of biosynthesis results in high yields of crystalline nanoparticles with a narrow size distribution and magnetic properties equal to the best chemically synthesized materials. In particular, it is demonstrated here that cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles with low temperature coercivity approaching 8 kOe and an effective anisotropy constant of {approx} 10{sup 6} erg cm{sup -3} can be manufactured through this biotechnological route. The dramatic enhancement in the magnetic properties of the nanoparticles by the introduction of high quantities of Co into the spinel structure represents a significant advance over previous biomineralization studies in this area using magnetotactic bacteria. The successful production of …
Date: March 24, 2009
Creator: Coker, Victoria S.; Telling, Neil D.; van der Laan, Gerrit; Pattrick, Richard A.D.; Pearce, Carolyn I.; Arenholz, Elke et al.
System: The UNT Digital Library
Hyperon static properties (open access)

Hyperon static properties

The static properties of the hyperons include masses, lifetimes, magnetic moments and CPT test from the asymmetries of these quantities for hyperon and anti-hyperon. The author reviews the present status of these measurements with an eye toward identifying places where new or improved measurements can have a significant physics impact. Most of these measurements are from the PDG where there have been only two new measurements quoted since 1995. He also reports two new measurements not yet published.
Date: March 24, 2000
Creator: Cooper, P.S.
System: The UNT Digital Library
Cpl6: The New Extensible, High-Performance Parallel Coupler forthe Community Climate System Model (open access)

Cpl6: The New Extensible, High-Performance Parallel Coupler forthe Community Climate System Model

Coupled climate models are large, multiphysics applications designed to simulate the Earth's climate and predict the response of the climate to any changes in the forcing or boundary conditions. The Community Climate System Model (CCSM) is a widely used state-of-art climate model that has released several versions to the climate community over the past ten years. Like many climate models, CCSM employs a coupler, a functional unit that coordinates the exchange of data between parts of climate system such as the atmosphere and ocean. This paper describes the new coupler, cpl6, contained in the latest version of CCSM,CCSM3. Cpl6 introduces distributed-memory parallelism to the coupler, a class library for important coupler functions, and a standardized interface for component models. Cpl6 is implemented entirely in Fortran90 and uses Model Coupling Toolkit as the base for most of its classes. Cpl6 gives improved performance over previous versions and scales well on multiple platforms.
Date: March 24, 2005
Creator: Craig, Anthony P.; Jacob, Robert L.; Kauffman, Brain; Bettge,Tom; Larson, Jay; Ong, Everest et al.
System: The UNT Digital Library
CZT Virtual Frisch-grid Detector: Principles and Applications (open access)

CZT Virtual Frisch-grid Detector: Principles and Applications

Cadmium Zinc Telluride (CdZnTe or CZT) is a very attractive material for using as room-temperature semiconductor detectors, because it has a wide bandgap and a high atomic number. However, due to the material's poor hole mobility, several special techniques were developed to ensure its suitability for radiation detection. Among them, the virtual Frisch-grid CZT detector is an attractive option, having a simple configuration, yet delivering an outstanding spectral performance. The goal of our group in Brookhaven National Laboratory (BNL) is to improve the performance of Frisch-ring CZT detectors; most recently, that effort focused on the non-contacting Frisch-ring detector, allowing us to build an inexpensive, large-volume detector array with high energy-resolution and a large effective area. In this paper, the principles of virtual Frisch-grid detectors are described, especially BNL's innovative improvements. The potential applications of virtual Frisch-grid detectors are discussed, and as an example, a hand-held gamma-ray spectrometer using a CZT virtual Frischgrid detector array is introduced, which is a self-contained device with a radiation detector, readout circuit, communication circuit, and high-voltage supply. It has good energy resolution of 1.4% (FWHM of 662-keV peak) with a total detection volume of {approx}20 cm{sup 3}. Such a portable inexpensive device can be used …
Date: March 24, 2009
Creator: Cui,Y.; Bolotnikov, A.; Camarda, G.; Hossain, A. & James, R. B.
System: The UNT Digital Library
RAPID MEASUREMENTS OF NEPTUNIUM OXIDATION STATES USING CHROMATOGRAPHIC RESINS (open access)

RAPID MEASUREMENTS OF NEPTUNIUM OXIDATION STATES USING CHROMATOGRAPHIC RESINS

The Savannah River Site's (SRS) H-Canyon facility uses ceric ammonium nitrate (CAN) to separate impure neptunium (Np) from a high sulfate feed stream. The material is processed using a two-pass solvent extraction purification which relies on CAN to oxidize neptunium to Np(VI) during the first pass prior to extraction. Spectrophotometric oxidation-state analyses normally used to validate successful oxidation to Np(VI) prior to extraction were compromised by this feed stream matrix. Therefore, a rapid chromatographic method to validate successful Np oxidation was developed using Eichrom Industries TRU and TEVA{reg_sign} resins. The method was validated and subsequently transferred to existing operations in the process analytical laboratories.
Date: March 24, 2009
Creator: Diprete, D; C Diprete, C; Mira Malek, M & Eddie Kyser, E
System: The UNT Digital Library
Solubility of Phenanthrene in Binary Mixtures of C1 - C4 Alcohols + 2-Propanol and Ethanol + Methanol at 298.2 K (open access)

Solubility of Phenanthrene in Binary Mixtures of C1 - C4 Alcohols + 2-Propanol and Ethanol + Methanol at 298.2 K

Article discussing the solubility of phenanthrene in binary mixtures of C1 - C4 alcohols + 2-propanol and ethanol + methanol at 298.2 K.
Date: March 24, 2009
Creator: Fakhree, Mohammad Amin Abolghassemi; Shayanfar, Ali; Acree, William E. (William Eugene) & Jouyban, Abolghasem
System: The UNT Digital Library
Naturalness re-examined: Implications for supersymmetry searches (open access)

Naturalness re-examined: Implications for supersymmetry searches

The authors discuss the origin of focus points in the scalar mass RGEs of the MSSM and their implications for collider searches. The authors present a new exact analytic solution to the homogeneous system of scalar mass TGEs in the MSSM for general tan {beta}. This is then used to prove that the focus point for m{sup 2}{sub H{sub u}} depends only on the value of the top Yukawa coupling at the weak scale (not its value at the GUT scale) and is independent of the bottom Yukawa coupling.
Date: March 24, 2000
Creator: Feng, J.L.; Matchev, K.T. & Moroi, Takeo
System: The UNT Digital Library
Analyses of Oxyanion Materials by Prompt Gamma Activation Analysis (open access)

Analyses of Oxyanion Materials by Prompt Gamma Activation Analysis

Prompt gamma activation analysis (PGAA) has been used to analyze metal ion oxyanion materials that have multiple applications, including medicine, materials, catalysts, and electronics. The significance for the need for accurate, highly sensitive analyses for the materials is discussed in the context of quality control of end products containing the parent element in each material. Applications of the analytical data for input to models and theoretical calculations related to the electronic and other properties of the materials are discussed.
Date: March 24, 2008
Creator: Firestone, Richard B.; Perry, D. L.; English, G. A.; Firestone, R. B.; Leung, K. N.; Garabedian, G. et al.
System: The UNT Digital Library
CLHEP -- New developments and directions (open access)

CLHEP -- New developments and directions

CLHEP is a broadly based collaboration, including developers at CERN, Cornell, FNAL, SLAC and elsewhere, to provide core C++ class libraries for the use of the HENP community. Recently, the collaboration aspect of CLHEP has been rejuvenated and expanded. To provide structure for the expanded collaboration, the developers have agreed to a consensus based organization centered around an editors list. An overview of the new structure, including the mechanism for ensuring CLHEP remains responsive to the needs of HENP users and other developers, will be presented. To guide directions of development, the nature of CLHEP has been clarified: The core CLHEP is structured as a set of packages which must have freely available sources and must be independent of external packages. These must work on at least a large fraction of the platforms in general use. The selection of these packages is driven by those needs and timetables of the High Energy and Nuclear Physics community which would not likely be met by code emerging from the general computing community. Coordination of CLHEP with other packages developed in HENP will be discussed, and recent and planned extensions to CLHEP will be presented.
Date: March 24, 2000
Creator: Fischler, M.S. & Pfeiffer, A.
System: The UNT Digital Library
Current status of MiniBooNE experiment (open access)

Current status of MiniBooNE experiment

This paper reviews the current status of the Fermilab mini-Booster neutrino experiment (MiniBooNE). The experiment began taking beam data in late August 2002. We describe the experiment, status of the beamline and detector, and show the first neutrino candidate events.
Date: March 24, 2003
Creator: Garcia, Fernanda G.
System: The UNT Digital Library