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Scientific Report (2002-2004) (open access)

Scientific Report (2002-2004)

OAK-B135 An overview of our work as well as two recent publications are contained in this scientific report. The work reported here revolves around the discovery of new coherent nonlinear kinetic waves in laser produced plasmas, we call KEEN waves (kinetic, electrostatic electron nonlinear waves), and optical mixing experiments on the Imega laser system at LLE with blue-green light for the exploration of ways to suppress parametric instabilities in long scale length, long pulsewidth laser-plasmas such as those which will be found on NIF or LMJ.
Date: May 11, 2004
Creator: Afeyan, Bedros
Object Type: Report
System: The UNT Digital Library
Electron Line Broadening in Plasmas: Resolution of the Quantum vs. Semiclassical Calculations Puzzle (open access)

Electron Line Broadening in Plasmas: Resolution of the Quantum vs. Semiclassical Calculations Puzzle

Puzzling discrepancies between on the one hand quantum mechanical (QM) electron impact calculations of isolated ion lines and on the other hand experimental data and nonperturbative semiclassical (SC) calculations are reviewed. The origin of these discrepancies was a standard line-broadening literature estimate of the wavefunction extent. The nonperturbative semiclassical calculations are further improved by dropping the long-range approximation and allowing penetrating collisions. This results in excellent agreement with fully quantal calculations for the case of the BIII 2s-2p line. On the other hand the standard perturbative semiclassical method is inadequate even in this particular example, where perturbation theory is valid. Further, the assumption of neglecting the back-reaction in semiclassical calculations is examined.
Date: May 11, 2004
Creator: Alexiou, S & Lee, R
Object Type: Article
System: The UNT Digital Library
Asymmetric injection of cathodic arc plasma into a macroparticlefilter (open access)

Asymmetric injection of cathodic arc plasma into a macroparticlefilter

The cathodic arc plasmas produced by cathode spots usuallyinclude macroparticles, which is undesirable for many applications. Acommon way of removing macroparticles is to use curved solenoid filterswhich guide the plasma from the source to the substrate. In this work, anarc source with relatively small cathode is used, limiting the possiblelocations of plasma production. The relative position of cathodic arcsource and macroparticle filtered was systematically varied and thefiltered plasma current was recorded. It was found that axis-symmetricplasma injection leads to maximum throughput only if an anode aperturewas used, which limited the plasma to near-axis flow by scraping offplasma at larger angles to the axis. When the anode aperture was removed,more plasma could enter the filter. In this case, maximum filtered ioncurrent was achieved when the plasma was injected off-axis, namely offsetin the direction where the filter is curved. Such behavior wasanticipated because the plasma column in the filter is known to beshifted by ExB and centrifugal drift as well as by non-axis-symmetriccomponents of the magnetic field in the filter entrance and exit plane.The data have implications for plasma transport variations caused bydifferent spot locations on cathodes that are not small compared to thefilter cross section.
Date: February 11, 2004
Creator: Anders, Andre & MacGill, Robert A.
Object Type: Article
System: The UNT Digital Library
Development of a Robust Tri-Carbide Fueled Reactor for Multimegawatt Space Power and Propulsion Applications (open access)

Development of a Robust Tri-Carbide Fueled Reactor for Multimegawatt Space Power and Propulsion Applications

An innovative reactor core design based on advanced, mixed carbide fuels was analyzed for nuclear space power applications. Solid solution, mixed carbide fuels such as (U,Zr,Nb)c and (U,Zr, Ta)C offer great promise as an advanced high temperature fuel for space power reactors.
Date: August 11, 2004
Creator: Anghaie, Samim; Knight, Travis W.; Plancher, Johann & Gouw, Reza
Object Type: Report
System: The UNT Digital Library
Effects of Radiative Recombination and Photon Recycling on Minority Carrier Lifetime in Epitaxial GaINAsSb Lattice-matched to GaSb (open access)

Effects of Radiative Recombination and Photon Recycling on Minority Carrier Lifetime in Epitaxial GaINAsSb Lattice-matched to GaSb

None
Date: May 11, 2004
Creator: Anikeev, S.; Donetsky, D.; Belenky, G.; Luryl, S.; Wang, C. A.; Shiau, D. A. et al.
Object Type: Report
System: The UNT Digital Library
Incident Analysis Report: B696 MOVER Event, August 19, 2004 (open access)

Incident Analysis Report: B696 MOVER Event, August 19, 2004

On August 19, 2004, three operators [employees of Washington TRU Solutions Central Characterization Project (CCP)] and one Health and Safety Technician [(H&ST), an employee of the University of California (UC)] were working in the mobile characterization unit, known as the Mobile Visual Examination and Repackaging Unit (MOVER). The unit, which was located in the Decontamination and Waste Treatment Facility (DWTF) Yard, uses a glovebox to repackage Transuranic (TRU) drums. Work was in progress on the last set of drums to be repackaged. Work had been completed on a TRU drum that was on its way out of the unit. Work had begun on a 0.6-plutonium-equivalent curie (PE Ci) TRU container. During the bag-in process for the 0.6-PE Ci container, operators encountered contamination measuring 6,000 counts per minute (cpm), or approximately 12,000 disintegrations per minute (dpm) on the exposed area of the drum port. The operators decontaminated the exposed, contaminated area of the drum port, and this exposed area was swiped again. The area was declared clean. During bag-out of the previous drum, operators noticed that the retaining band was not tightened optimally; therefore, the retaining band was replaced with a new one on this drum. The three operators and LLNL …
Date: November 11, 2004
Creator: Beach, D. R.; Carr, S.; Anderson, B.; Lewis, J.; Merrigan, J.; Richards, J. et al.
Object Type: Report
System: The UNT Digital Library
The Magnesium Branch of the Tetrapyrrole Biosynthetic Pathway (open access)

The Magnesium Branch of the Tetrapyrrole Biosynthetic Pathway

It should be noted that the focus of the research changed somewhat during the course of the current award. The initial focus is indicated by the title of the current grant, ''The Magnesium Branch of the Chlorophyll Biosynthetic Pathway''. During the current grant period, Dr. Robert Willows, a postdoctoral associate, joined the faculty of McQuarie University in Australia. When he left my lab, we decided that he should independently pursue research on structure/function relationships in Mg chelatase and that our laboratories would collaborate on regulatory studies of this enzyme. Also, during the current award period, I began collaborating with Dr. Ariane Atteia and Mr. Robert van Lis, who were at the time located at the Autonomous University of Mexico. Dr. Atteia has since joined my laboratory and Mr. van Lis will also do so when he obtains his Ph.D. in the near future. These individuals bring to the laboratory their interests and expertise in the respiratory components of Chlamydomonas and their desire to become experts in tetrapyrrole metabolism. Recently, in a collaboration with Dr. David Bollivar, a former postdoctoral associate who is now at Illinois Wesleyan University, and Dr. Caroline Walker, who was at Clemson University but has since left …
Date: May 11, 2004
Creator: Beale, S. I.
Object Type: Report
System: The UNT Digital Library
Modeling and characterization of recompressed damaged materials (open access)

Modeling and characterization of recompressed damaged materials

Experiments have been performed to explore conditions under which spall damage is recompressed with the ultimate goal of developing a predictive model. Spall is introduced through traditional gas gun techniques or with laser ablation. Recompression techniques producing a uniaxial stress state, such as a Hopkinson bar, do not create sufficient confinement to close the porosity. Higher stress triaxialities achieved through a gas gun or laser recompression can close the spall. Characterization of the recompressed samples by optical metallography and electron microscopy reveal a narrow, highly deformed process zone. At the higher pressures achieved in the gas gun, little evidence of spall remains other than differentially etched features in the optical micrographs. With the very high strain rates achieved with laser techniques there is jetting from voids and other signs of turbulent metal flow. Simulations of spall and recompression on micromechanical models containing a single void suggest that it might be possible to represent the recompression using models similar to those employed for void growth. Calculations using multiple, randomly distributed voids are needed to determine if such models will yield the proper behavior for more realistic microstructures.
Date: February 11, 2004
Creator: Becker, R.; Cazamias, J. U.; Kalantar, D. H.; LeBlanc, M. M. & Springer, H. K.
Object Type: Report
System: The UNT Digital Library
Protocols for Thermoluninescence and Optically Stimulated Luminescence Research at DOSAR (open access)

Protocols for Thermoluninescence and Optically Stimulated Luminescence Research at DOSAR

The Life Sciences Division (LSD) of Oak Ridge National Laboratory (ORNL) has a long record of radiation dosimetry research at the Dosimetry Applications Research (DOSAR) facility complex. These facilities have been used by a broad segment of the research community to perform a variety of experiments in areas including, but not limited to, radiobiology, radiation dosimeter and instrumentation development and calibration, and materials testing in a variety of radiation environments. Collaborations with the University of Tennessee-Knoxville (UTK) have also led to important contributions in the area of archaeometry, particularly as it relates to the use of radiation dosimetry to date archaeological artifacts. This manual is to serve as the primary instruction and operation manual for dosimetric and archaeometric research at DOSAR involving thermoluminescence (TL) and optically stimulated luminescence (OSL). Its purpose is to (1) provide protocols for common practices associated with the research, (2) outline the relevant organizational structure, (3) identify the Quality Assurance plan, and (4) describe all the procedures, operations, and responsibilities for safe and proper operation of associated equipment. Each person who performs research at DOSAR using TL/OSL equipment is required to read the latest revision of this manual and be familiar with its contents, and to …
Date: October 11, 2004
Creator: Bernal, S. M. & Bogard, J. S.
Object Type: Report
System: The UNT Digital Library

Comparison of up-scaling methods in poroelasticity and its generalizations

None
Date: June 11, 2004
Creator: Berryman, James G.
Object Type: Presentation
System: The UNT Digital Library
Diagnostics for intense heavy ion beams in the HIF-VNL (open access)

Diagnostics for intense heavy ion beams in the HIF-VNL

Modern diagnostic techniques provide detailed information on beam conditions in injector, transport, and final focus experiments in the HIF-VNL. Parameters of interest include beam current, beam energy, transverse and longitudinal distributions, emittance, and space charge neutralization. Imaging techniques, based on kapton films and optical scintillators, complement and in some cases, may replace conventional techniques based on slit scans. Time-resolved optical diagnostics that provide 4-D transverse information on the experimental beams are in operation on the existing experiments. Current work includes a compact optical diagnostic suitable for insertion in transport lines, improved algorithms for optical data analysis and interpretation, a high-resolution electrostatic energy analyzer, and an electron beam probe. A longitudinal diagnostic kicker generates longitudinal space-charge waves that travel on the beam. Time of flight of the space charge waves and an electrostatic energy analyzer provide an absolute measure of the beam energy. Special diagnostics to detect secondary electrons and gases desorbed from the wall have been developed.
Date: June 11, 2004
Creator: Bieniosek, F. M.; Eylon, S.; Faltens, A.; Friedman, A.; Kwan, J. W.; Leitner, M. A. et al.
Object Type: Article
System: The UNT Digital Library
Methods for Calibrating Basin-Wide Hydroacoustic Propagation in the Indian Ocean (open access)

Methods for Calibrating Basin-Wide Hydroacoustic Propagation in the Indian Ocean

This collaborative project was designed to test and compare methods for achieving full ocean basin propagation of hydroacoustic signals in the 5-100 Hz frequency band. Plans for a systematic calibration of the International Monitoring System (IMS) for nuclear testing were under consideration in 2000/2001. The results from this project provide information to guide such planning for future ocean basin calibration work. Several acoustic source types were tested during two sea-going experiments and most were successful at generating signals that propagated hundreds to thousands of km to be recorded at the Indian Ocean IMS hydrophone stations. Development and numerical modeling of imploding glass sphere sources was one component of this testing. The intent was to design a relatively simple-to-use source that is not subject to restrictions that can limit use of explosive charges, but whose signal is large enough to propagate 100-1000's km range. Analysis of IMS hydrophone data recording during the experiments was used to illustrate the extent of energy loss during signal propagation and to assess the accuracy with which the small acoustic sources could be located using methods typically employed for nuclear monitoring.
Date: October 11, 2004
Creator: Blackman, D; de Groot-Hedlin, C; Orcutt, J A; Harben, P H; Clarke, D B & Ramirez, A L
Object Type: Report
System: The UNT Digital Library
Type Ia supernova rate at a redshift of ~;0.1 (open access)

Type Ia supernova rate at a redshift of ~;0.1

We present the type Ia rate measurement based on two EROS supernova search campaigns (in 1999 and 2000). Sixteen supernovae identified as type Ia were discovered. The measurement of the detection efficiency, using a Monte Carlo simulation, provides the type Ia supernova explosion rate at a redshift {approx} 0.13. The result is 0.125{sub -0.034-0.028}{sup +0.044+0.028} h{sub 70}{sup 2} SNu where 1 SNu = 1 SN/10{sup 10} L{sub {circle_dot}}{sup B}/century. This value is compatible with the previous EROS measurement (Hardin et al. 2000), done with a much smaller sample, at a similar redshift. Comparison with other values at different redshifts suggests an evolution of the type Ia supernova rate.
Date: May 11, 2004
Creator: Blanc, G.; Afonso, C.; Alard, C.; Albert, J. N.; Aldering, G.; Amadon, A. et al.
Object Type: Article
System: The UNT Digital Library
A comparative analysis of business structures suitable forfarmer-owned wind power projects in the United States (open access)

A comparative analysis of business structures suitable forfarmer-owned wind power projects in the United States

For years, farmers in the United States have looked with envy on their European counterparts' ability to profitably farm the wind through ownership of distributed, utility-scale wind projects. Only within the past few years, however, has farmer- or community-owned wind power development become a reality in the United States. The primary hurdle to this type of development in the United States has been devising and implementing suitable business and legal structures that enable such projects to take advantage of tax-based federal incentives for wind power. This article discusses the limitations of such incentives in supporting farmer- or community-owned wind projects, describes four ownership structures that potentially overcome such limitations, and finally conducts comparative financial analysis on those four structures, using as an example a hypothetical 1.5 MW farmer-owned project located in the state of Oregon. We find that material differences in the competitiveness of each structure do exist, but that choosing the best structure for a given project will largely depend on the conditions at hand; e.g., the ability of the farmer(s) to utilize tax credits, preference for individual versus ''cooperative'' ownership, and the state and utility service territory in which the project will be located.
Date: November 11, 2004
Creator: Bolinger, Mark & Wiser, Ryan
Object Type: Report
System: The UNT Digital Library
Potential Military Use of Airships and Aerostats (open access)

Potential Military Use of Airships and Aerostats

None
Date: November 11, 2004
Creator: Bolkcom, Christopher
Object Type: Report
System: The UNT Digital Library
Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance (open access)

Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

This project involves the design and synthesis of receptors for oxoanions of environmental importance, including emphasis on high level and low activity waste. Target anions have included primarily oxoanions and a study of the basic concepts behind selective binding of target anions. A primary target has been sulfate because of its deleterious influence on the vitrification of tank wastes
Date: December 11, 2004
Creator: Bowman-James, K.; Wilson, G. & Moyer, B. A.
Object Type: Report
System: The UNT Digital Library
Parallel Algebraic Multigrids for Structural mechanics (open access)

Parallel Algebraic Multigrids for Structural mechanics

This paper presents the results of a comparison of three parallel algebraic multigrid (AMG) preconditioners for structural mechanics applications. In particular, they are interested in investigating both the scalability and robustness of the preconditioners. Numerical results are given for a range of structural mechanics problems with various degrees of difficulty.
Date: May 11, 2004
Creator: Brezina, M; Tong, C & Becker, R
Object Type: Article
System: The UNT Digital Library
Army Transformation and Modernization: Overview and Issues for Congress (open access)

Army Transformation and Modernization: Overview and Issues for Congress

This report briefly describes the modernization program for the U.S. military forces and discusses issues of feasibility, viability, and affordability of potential interest to Congress.
Date: March 11, 2004
Creator: Bruner, Edward F.
Object Type: Report
System: The UNT Digital Library
Analysis of design tradeoffs for diplay case evaporators (open access)

Analysis of design tradeoffs for diplay case evaporators

A model for simulating a display case evaporator under frosting conditions has been developed, using a quasi-steady and finite-volume approach and a Newton-Raphson based solution algorithm. It is capable of simulating evaporators with multiple modules having different geometries, e.g. tube and fin thicknesses and pitch. The model was validated against data taken at two-minute intervals from a well-instrumented medium-temperature vertical display case, for two evaporators having very different configurations. The data from these experiments provided both the input data for the model and also the data to compare the modeling results. The validated model has been used to generate some general guidelines for coil design. Effects of various geometrical parameters were quantified, and compressor performance data were used to express the results in terms of total power consumption. Using these general guidelines, a new prototype evaporator was designed for the subject display case, keeping in mind the current packaging restrictions, tube and fin availabilities. It is an optimum coil for the given external load conditions. Subsequently, the validated model was used in a more extensive analysis to design prototype coils with some of the current tube and fin spacing restrictions removed. A new microchannel based suction line heat exchanger was …
Date: August 11, 2004
Creator: Bullard, CLARK
Object Type: Report
System: The UNT Digital Library
Welfare Reform: An Issue Overview (open access)

Welfare Reform: An Issue Overview

None
Date: March 11, 2004
Creator: Burke, Vee
Object Type: Report
System: The UNT Digital Library
Insights into the evolution of Yersinia pestis through whole genome comparison with Yersinia pseudotuberculosis (open access)

Insights into the evolution of Yersinia pestis through whole genome comparison with Yersinia pseudotuberculosis

None
Date: August 11, 2004
Creator: Chain, P.; Carniel, E.; Larimer, F.; Lamerdin, J.; Stoutland, P.; Regala, W. et al.
Object Type: Article
System: The UNT Digital Library
Proteomic Characterization of Host Response to Yersinia pestis (open access)

Proteomic Characterization of Host Response to Yersinia pestis

Host-pathogen interactions result in protein expression changes within both the host and the pathogen. Here, results from proteomic characterization of host response following exposure to Yersinia pestis, the causative agent of plague, and to two near neighbors, Y. pseudotuberculosis and Y. enterocolitica, are reported. Human monocyte-like cells were chosen as a model for macrophage immune response to pathogen exposure. Two-dimensional electrophoresis followed by mass spectrometry was used to identify host proteins with differential expression following exposure to these three closely related Yersinia species. This comparative proteomic characterization of host response clearly shows that host protein expression patterns are distinct for the different pathogen exposures, and contributes to further understanding of Y. pestis virulence and host defense mechanisms. This work also lays the foundation for future studies aimed at defining biomarkers for presymptomatic detection of plague.
Date: May 11, 2004
Creator: Chromy, B.; Perkins, J.; Heidbrink, J.; Gonzales, A.; Murhpy, G.; Fitch, J. P. et al.
Object Type: Article
System: The UNT Digital Library
Evaluation of the DWPF Cold Chem Dissolution Method with Tank 7 and Tank 51 Radioactive Sludge (open access)

Evaluation of the DWPF Cold Chem Dissolution Method with Tank 7 and Tank 51 Radioactive Sludge

Dissolution experiments were conducted on radioactive sludge from Tank 7, before transfer of the contents of Tank 7 to Tank 51, and the subsequent sludge in Tank 51 to evaluate the effectiveness of the DWPF Cold Chem Method. The DWPF Cold Chem Method is a room temperature dissolution method (DWPF Cold Chem Method) used in the DWPF on the Slurry Receipt and Adjustment Tank (SRAT) samples in preparation for instrumental analysis. Four types of dissolutions experiments were carried out, the DWPF Cold Chem Method, hot aqua regia, sodium peroxide fusion and hot HF-HNO3. The hot HF-HNO3 digestion is modified version of the DWPF method that incorporates a heating step. The hot aqua regia and sodium peroxide fusion digestions were included as reference digestions. The resulting solutions from all the sludge digestions were analyzed by ICP-ES (Inductively Coupled Plasma Emission Spectroscopy). Visual observations and ICP-ES results were used to evaluate the effectiveness of the DWPF Cold Chem by comparison to the hot aqua regia, sodium peroxide fusion and the hot HF-HNO3 digestions. The data and experimental observations support the following conclusions: The DWPF Cold Chem Method seemed to be effective at dissolving initial species of radioactive sludge, but concurrent precipitation of …
Date: March 11, 2004
Creator: Click, D.R.
Object Type: Report
System: The UNT Digital Library
Comparison of Electron Cloud Simulation and Experiments in the High-Current Experiment (open access)

Comparison of Electron Cloud Simulation and Experiments in the High-Current Experiment

Contaminating clouds of electrons are a common concern for accelerators of positive-charged particles, but there are some unique aspects of heavy-ion accelerators for fusion and high-energy density physics which make modeling such clouds especially challenging. In particular, self-consistent electron and ion simulation is required, including a particle advance scheme which can follow electrons in regions where electrons are strongly, weakly, and un-magnetized. We describe our approach to such self-consistency, and in particular a scheme for interpolating between full-orbit (Boris) and drift-kinetic particle pushes that enables electron time steps long compared to the typical gyro period in the magnets. We present tests and applications: simulation of electron clouds produced by three different kinds of sources indicates the sensitivity of the cloud shape to the nature of the source; first-of-a-kind self-consistent simulation of electron-cloud experiments on the High-Current Experiment (HCX) at LBNL, in which the machine can be flooded with electrons released by impact of the ion beam on an end plate, demonstrate the ability to reproduce key features of the ion-beam phase space; and simulation of a two-stream instability of thin beams in a magnetic field demonstrate the ability of the large-timestep mover to accurately calculate the instability.
Date: November 11, 2004
Creator: Cohen, R H; Friedman, A; Covo, M K; Lund, S M; Molvik, A W; Bieniosek, F M et al.
Object Type: Article
System: The UNT Digital Library