Resource Type

Texas Racing Commission Annual Report: 2005 (open access)

Texas Racing Commission Annual Report: 2005

Annual report of the Texas Racing Commission describing goals, activities, and accomplishments during fiscal year 2005.
Date: March 2, 2007
Creator: Texas Racing Commission
System: The Portal to Texas History
Rapid Qualitative Risk Assessment for Contaminant Leakage From Coal Seams During Underground Coal Gasification and CO2 Injection (open access)

Rapid Qualitative Risk Assessment for Contaminant Leakage From Coal Seams During Underground Coal Gasification and CO2 Injection

One of the major risks associated with underground coal gasification is contamination of local aquifers with a variety of toxic compounds. It is likely that the rate, volume, extent, and concentrations of contaminant plumes will depend on the local permeability field near the point of gasification. This field depends heavily on the geological history of stratigraphic deposition and the specifics of stratigraphic succession. Some coals are thick and isolated, whereas others are thinner and more regionally expressed. Some coals are overlain by impermeable units, such as marine or lacustrine shales, whereas others are overlain by permeable zones associated with deltaic or fluvial successions. Rapid stratigraphic characterization of the succession provides first order information as to the general risk of contaminant escape, which provides a means of ranking coal contaminant risks by their depositional context. This risk categorization could also be used for ranking the relative risk of CO{sub 2} escape from injected coal seams. Further work is needed to verify accuracy and provide some quantification of risks.
Date: July 2, 2004
Creator: Friedmann, S J
System: The UNT Digital Library
Hanford Site Environmental Report for Calendar Year 2001 (open access)

Hanford Site Environmental Report for Calendar Year 2001

This report summarizes environmental information for the Hanford Site in Washington State for the calendar year 2001.
Date: September 2, 2002
Creator: Poston, Ted M.; Hanf, Robert W.; Dirkes, Roger L. & Morasch, Launa F.
System: The UNT Digital Library
Low-Activity Waste Glass Studies: FY2000 Summary Report (open access)

Low-Activity Waste Glass Studies: FY2000 Summary Report

Over 200 single-pass flow-through experiments were completed with LAWABP1 glass, the reference glass for the 2001 Immobilized Low-Activity Waste Performance Assessment. These data provided the kinetic rate law parameters and Na ion-exchange rate needed to conduct long-term performance analyses using the reactive chemical transport code STORM. Pressurized unsaturated flow (PUF) experiments with five prototypic LAW glasses were also performed. The PUF test provides a means to dramatically accelerate the weathering process in a simulated vadose zone environment. The performance of these five next generation LAW glasses in the PUF test (and other accelerated tests) improved dramatically from earlier glass compositions that were being developed by BNFL, Inc. No autocatalytic corrosion rate accelerations were observed in tests that were conducted for over 1 year. SPFT and PUF experiments were run with a commercial humic acid solution, 25 to 50 times more concentrated than expected in Hanford vadose zone pore water. No difference in glass dissolution rate versus the rate measured in deionized water could be detected within experimental error. Initial development and testing of a parallelized lattice-Boltzmann method for solving reactive chemical transport problems in complex geometries was completed. This method is being examined as a means to dramatically decrease the …
Date: November 2, 2000
Creator: McGrail, B. Peter; Icenhower, Jonathan P.; Martin, Paul F.; Rector, David R.; Schaef, Herbert T.; Rodriguez, Elsa A. et al.
System: The UNT Digital Library
Measurement of 150-Sm(n,2ngammai) 149-Sm cross sections between threshold and 20 MeV (open access)

Measurement of 150-Sm(n,2ngammai) 149-Sm cross sections between threshold and 20 MeV

Absolute partial {gamma}-ray cross sections for the production of discrete {gamma}-rays from the reaction {sup 150}Sm(n,2n{gamma}{sub i}){sup 149}Sm were measured using the GEANIE {gamma}-ray spectrometer coupled with the intense white neutron source at WNR/LANSCE. The measurements were made for incident neutron energies between threshold (8.04 MeV) and 20 MeV. The partial cross sections for 21 {gamma}-rays were extracted from the data. Of these, 17 were compared to calculations performed using the enhanced Hauser-Feshbach code STAPRE. The partial {gamma}-ray cross sections of the observed parallel decay paths to the ground state were summed, forming a lower bound for the (n,2n) reaction channel. A combination of theory and experiment was then used to deduce the (n,2n) reaction channel cross section.
Date: August 2, 2004
Creator: Cooper, J.; Becker, J.; Dashdorj, D.; Dietrich, F. S.; Garrett, P.; Hoffman, R. et al.
System: The UNT Digital Library
Analysis of Shock-Void Experiment (open access)

Analysis of Shock-Void Experiment

The authors compare CALE simulations with recent experimental results of a laser-induced shock traversing a spherical under-dense region (''void''). In this report the experimental results are described, as well as several numerical attempts at explaining the observed radiographs. The conclusion is that the numerical simulations at this time cannot satisfactorily explain the experiment. The simulations also indicate that the introduction of air gaps between the under-dense sphere and the surrounding foam can greatly change the behavior of the shocked sphere. Thus fabrication details may play an important role in the detailed evolution of this experiment. Regardless of the simulations, analysis of the observed time sequence indicates that reproducibility of this experiment may be a factor. To settle this issue, further experiments of this kind will be required.
Date: May 2, 2003
Creator: Woods, D T; Robey, H & Stry, P
System: The UNT Digital Library
A Compendium of Transfer Factors for Agricultural and Animal Products (open access)

A Compendium of Transfer Factors for Agricultural and Animal Products

Transfer factors are used in radiological risk assessments to estimate the amount of radioactivity that could be present in a food crop or organism based on the calculated concentration in the source medium (i.e., soil or animal feed). By calculating the concentration in the food, the total intake can be estimated and a dose calculated as a result of the annual intake. This report compiles transfer factors for radiological risk assessments, using common food products, including meats, eggs, and plants. Transfer factors used were most often selected from recommended values listed by national or international organizations for use in radiological food chain transport calculations. Several methods of estimation and extrapolation were used for radionuclides not listed in the primary information sources. Tables of transfer factors are listed by element and information source for beef, eggs, fish, fruit, grain, leafy vegetation, milk, poultry, and root vegetables.
Date: June 2, 2003
Creator: Staven, Lissa H.; Napier, Bruce A.; Rhoads, Kathleen & Strenge, Dennis L.
System: The UNT Digital Library
Beyond the dna: a prototype for functional genomics (open access)

Beyond the dna: a prototype for functional genomics

A prototype oligonucleotide ''functional chip'' has been developed to screen novel DNA repair proteins for their ability to bind or alter different forms of DNA. This chip has been developed as a functional genomics screen for analysis of protein-DNA interactions for novel proteins identified from the Human Genome Project The process of novel gene identification that has ensued as a consequence of available sequence information is remarkable. The challenge how lies in determining the function of newly identified gene products in a time-and cost-effective high-throughput manner. The functional chip is generated by the robotic application of DNA spotted in a microarray format onto a glass slide. Individual proteins are then analyzed against the different form of DNA bound to the slide. Several prototype functional chips were designed to contain various DNA fragments tethered to a glass slide for analysis of protein-DNA binding or enzymatic activity of known proteins. The technology has been developed to screen novel, putative DNA repair proteins for their ability to bind various types of DNA alone and in concert with protein partners. An additional scheme has been devised to screen putative repair enzymes for their ability to process different types of DNA molecules. Current methods to …
Date: March 2, 2000
Creator: Albala, J
System: The UNT Digital Library
Matrix Diffusion and Colloid-Facilitated Transport in Fractured Rocks: Model and Parameter Validation (open access)

Matrix Diffusion and Colloid-Facilitated Transport in Fractured Rocks: Model and Parameter Validation

In this report, we review the results of Reimus et al. (2000a; 2000b) regarding matrix diffusion and colloid-facilitated transport in fractured rock and evaluate the implications of these results on modeling fracture flow at the Nevada Test Site (NTS). In particular, we examine these data in the context of the recent Cheshire hydrologic source term (HST) model results (Pawloski et al., 2001). This report is divided into several sections. In the first, we evaluate the effective diffusion coefficient (D{sub e}) data reported in Reimus et al. (2000a) for conservative tracer species ({sup 3}H, {sup 14}C, and {sup 99}Tc) and fit a simple effective diffusion model to these data. In the second, we use the fitted effective diffusion model, in conjunction with a surface complexation model, to simulate plutonium-colloid transport and compare model results to data reported in Reimus et al. (2000b). In the third, we evaluate the implications of these data with regards to radionuclide transport through fractures at the field scale and, in particular, with regards to the Cheshire HST model (Pawloski et al., 2001). Finally, we make recommendations regarding future radionuclide transport modeling efforts at the NTS.
Date: August 2, 2002
Creator: Zavarin, M
System: The UNT Digital Library
Post-Closure Groundwater Monitoring Plan for the 1324-N Surface Impoundment and 1324-NA Percolation Pond (open access)

Post-Closure Groundwater Monitoring Plan for the 1324-N Surface Impoundment and 1324-NA Percolation Pond

The 1324-N Surface Impoundment and the 1324-NA Percolation Pond, located in the 100-N Area of the Hanford Site, are regulated under the Resource Consevation and Recovery Act (RCRA). Surface and underground features of the facilities have been removed and laboratory analyses showed that soil met the closure performance standards. These sites have been backfilled and revegetated.
Date: April 2, 2004
Creator: Hartman, Mary J.
System: The UNT Digital Library
Three-Dimensional Modeling of DNAPL in the Subsurface of the 216-Z-9 Trench at the Hanford Site (open access)

Three-Dimensional Modeling of DNAPL in the Subsurface of the 216-Z-9 Trench at the Hanford Site

This work describes numerical modeling for simulating carbon tetrachloride flow and transport as outlined in two DOE reports for the 200-PW-1 Operable Unit and the 200-PW-1, 200-PW-3, and 200-PW-6 Operable Units. Simulations using the multifluid flow model STOMP were conducted to estimate how disposed dense nonaqueous phase liquid migrates in the vadose zone.
Date: November 2, 2004
Creator: Oostrom, Mart; Rockhold, Mark L.; Thorne, Paul D.; Last, George V. & Truex, Michael J.
System: The UNT Digital Library
Magnetic properties of ultra thin epitaxial Fe films on GaAs(001) (open access)

Magnetic properties of ultra thin epitaxial Fe films on GaAs(001)

The magnetic properties of epitaxial Fe films on GaAs in the range of the first few monolayers have been the subject of a considerable number of investigations in recent years. The absence of magnetic signatures at room temperature has been attributed to the existence of a magnetic ''dead'' layer as well as superparamagnetism. By examining the temperature dependence of the magnetic linear dichroism of the Fe core level photoelectrons, we found that these ''non-ferromagnetic'' layers had in fact a Curie temperature, T{sub c}, substantially lower than room temperature, e.g., a T{sub c} of about 240K for thin films of a nominal thickness of 0.9 nm. The values of Curie temperature were sensitive to the initial GaAs substrate conditions and the thickness of the Fe over-layer with a layer of thickness of 1.25 nm showing a T{sub c} above room temperature. The data suggest that the ultrathin Fe films on GaAs(001) are ferromagnetic, although a weaker exchange interaction in the films lead to a substantial reduction in Curie temperature.
Date: October 2, 2003
Creator: Morton, S A; Tobin, J G; Spangenberg, M; Neal, J R; Shen, T H; Waddill, G D et al.
System: The UNT Digital Library
Effects of Globally Waste Disturbing Activities on Gas Generation, Retention, and Release in Hanford Waste Tanks (open access)

Effects of Globally Waste Disturbing Activities on Gas Generation, Retention, and Release in Hanford Waste Tanks

Various operations are authorized in Hanford single- and double-shell tanks that disturb all or a large fraction of the waste. These globally waste-disturbing activities have the potential to release a large fraction of the retained flammable gas and to affect future gas generation, retention, and release behavior. This report presents analyses of the expected flammable gas release mechanisms and the potential release rates and volumes resulting from these activities. The background of the flammable gas safety issue at Hanford is summarized, as is the current understanding of gas generation, retention, and release phenomena. Considerations for gas monitoring and assessment of the potential for changes in tank classification and steady-state flammability are given.
Date: August 2, 2005
Creator: Stewart, Charles W.; Fountain, Matthew S.; Huckaby, James L.; Mahoney, Lenna A.; Meyer, Perry A. & Wells, Beric E.
System: The UNT Digital Library
A Task-parallel Clustering Algorithm for Structured AMR (open access)

A Task-parallel Clustering Algorithm for Structured AMR

A new parallel algorithm, based on the Berger-Rigoutsos algorithm for clustering grid points into logically rectangular regions, is presented. The clustering operation is frequently performed in the dynamic gridding steps of structured adaptive mesh refinement (SAMR) calculations. A previous study revealed that although the cost of clustering is generally insignificant for smaller problems run on relatively few processors, the algorithm scaled inefficiently in parallel and its cost grows with problem size. Hence, it can become significant for large scale problems run on very large parallel machines, such as the new BlueGene system (which has {Omicron}(10{sup 4}) processors). We propose a new task-parallel algorithm designed to reduce communication wait times. Performance was assessed using dynamic SAMR re-gridding operations on up to 16K processors of currently available computers at Lawrence Livermore National Laboratory. The new algorithm was shown to be up to an order of magnitude faster than the baseline algorithm and had better scaling trends.
Date: November 2, 2004
Creator: Gunney, B N & Wissink, A M
System: The UNT Digital Library
Efficiency Issues in Parallel Coarsening Schemes (open access)

Efficiency Issues in Parallel Coarsening Schemes

Various options for sequential, shared memory and distributed memory implementations for the CLJP algorithm, a parallel coarsening scheme within algebraic multigrid, are discussed. The use of different data structures as well as different approaches of implementing the actual algorithm are investigated, and experimental results illustrating the results are presented.
Date: May 2, 2003
Creator: Gallivan, K A & Yang, U M
System: The UNT Digital Library
Data vs Monte Carlo Comparison of NN1 Detector (open access)

Data vs Monte Carlo Comparison of NN1 Detector

In this note, we demonstrate agreement between data and Geant4 simulations of the NN1 double-sided germanium detector using a {sup 22}Na source.
Date: August 2, 2004
Creator: Lange, D; Wright, D; Burks, M & Jordan, E
System: The UNT Digital Library
XPS Studies of Yb14MnSb11 and Yb14ZnSb11 (open access)

XPS Studies of Yb14MnSb11 and Yb14ZnSb11

Measurements of core and valence electronic states of single crystals of the rare earth transition metal Zintl phases Yb{sub 14}MnSb{sub 11} and Yb{sub 14}ZnSb{sub 11} were performed using the X-ray photoelectron spectroscopy station of Beamline 7 at the Advanced Light Source. Sample surfaces of Yb{sub 14}MnSb{sub 11} and Yb{sub 14}ZnSb{sub 11} were measured as received, after Ar{sup +} ion bombardment, and after cleaving in situ. Detailed analysis of the clean Mn and Zn analog sample surfaces reveal a significant contribution of both Yb{sup 3+} and Yb{sup 2+} 4f states in the valence band region for the Zn analog and no contribution of Yb{sup 3+} states to the valence band for the Mn analog. This result is predicted for the Zn analog by Zintl counting rules, and single crystal X-ray diffraction studies presented here also support the mixed valency of Yb for Yb{sub 14}ZnSb{sub 11}. Further detailed analysis of the core and valence band structure of both Yb{sub 14}MnSb{sub 11} and Yb{sub 14}ZnSb{sub 11} will be presented.
Date: October 2, 2003
Creator: Holm, A. P.; Ozawa, T. C.; Kauzlarich, S. M.; Morton, S. A.; Waddill, G. D.; Pickett, W. E. et al.
System: The UNT Digital Library
Data Quality Objectives Summary Report - Designing a Groundwater Monitoring and Assessment Network for the 100-BC-5 and 100-FR-3 Operable Units (open access)

Data Quality Objectives Summary Report - Designing a Groundwater Monitoring and Assessment Network for the 100-BC-5 and 100-FR-3 Operable Units

The 100-BC-5 and 100-FR-3 Operable Units are defined for groundwater beneath the 100-B/C and 100-F Areas, respectively. Each operable unit has undergone a limited field investigation and qualitative risk assessment as part of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) remedial investigation process. Although decisions have been made to perform active remediation of contaminant sources, no decision has yet been made concerning remedial actions for groundwater at either operable unit. During this interim period, groundwater monitoring has been conducted in accordance with groundwater sampling and analysis plan for the 100-BC-5 Operable Unit (Sweeney 2002a) and 100-FR-3 Operable Unit (Sweeney 2002b) under Federal Facility Agreement and Consent Order (TPA) change control agreements between the U.S. Department of Energy (DOE) and U.S. Environmental Protection Agency (EPA). This report is the culmination of the decision process that will guide future data acquisition at these two operable units. The data gathered will be used to develop future closure decisions, leading ultimately toward a record of decision for the 100-BC-5 and 100-FR-3 Operable Units. Detailed background information that includes facility description, groundwater flow directions, monitoring network and monitoring constituents, constituents of potential concern, summary of groundwater contamination levels, sources of groundwater …
Date: June 2, 2003
Creator: Sweeney, Mark D. & Chou, Charissa J.
System: The UNT Digital Library
A Manufacturing Process for Precision Gold Support Rings for Laser Targets (open access)

A Manufacturing Process for Precision Gold Support Rings for Laser Targets

A research effort performed by the Target Fabrication Group has developed a method for producing precision, meso-scale gold support rings for laser targets. Many different laser targets consist of planar components that are built upon a gold support ring, such as the HyDiv and RadG targets shown in Figure 1. Because of the sequence in which laser targets such as these must be built to achieve the required overall precision, the washer-shaped support rings must fit precisely onto fixtures that are used throughout the manufacturing process. Because the support ring is the fundamental structure onto which the target is built, any imprecision in the support ring propagates through the entire target. Thus, even if the physics performance of a laser target does not require a flat and precise support ring, the manufacturing methods used to achieve the overall level of precision demanded in the targets rely heavily on the precision of the support rings. Past efforts to purchase gold support rings from outside vendors have been either extremely costly, or the vendors were unable to deliver acceptable parts. On several occasions, difficulties in obtaining acceptable support rings in a timely manner have compromised the ability to manufacture and deliver targets …
Date: March 2, 2004
Creator: Hibbard, R L & Bono, M J
System: The UNT Digital Library
CCI1 Basic Detector Performance (open access)

CCI1 Basic Detector Performance

This document describes the basic detector performance for the CCI1 device, which consists of the Si2 and Ge2 detector components.
Date: June 2, 2005
Creator: Lange, D; Manini, H; Wright, D; Cunningham, M & Vetter, K
System: The UNT Digital Library
Experimental Results in Support of Simulating Progressive Crush in Carbon-Fiber Textile Composites (open access)

Experimental Results in Support of Simulating Progressive Crush in Carbon-Fiber Textile Composites

This report summarizes the findings of an experimental program conducted to support the modeling of the crush behavior of triaxial braid carbon fiber composites. The matrix material as well as braided panels and tubes were characterized in order to determine material properties, to assess failure modes, and to provide a test bed for new analytical and numerical tools developed specifically for braided composites. The matrix material selected by the ACC was an epoxy vinyl ester (Ashland Hetron 922). Tensile tests were used to compare two formulations-one used by the ACC and one recommended by the resin supplier. The latter was a faster reacting system and gelled in one-third the time of the ACC formulation. Both formulations had an average elongation at failure that was only half of the resin supplier's reported value. Only one specimen of each type came close to the reported elongation value and it was shown that failure invariably initiated at both surface and internal defects. Overall, the tensile properties of the two formulations were nearly identical, but those of the ACC system were more consistent. The properties of the ACC matrix formulation were measured in tension, shear, and compression and the average properties obtained in these …
Date: April 2, 2001
Creator: DeTeresa, S J; Allison, L M; Cunningham, B J; Freeman, DC; Saculla, M D; Sanchez, R J et al.
System: The UNT Digital Library
High-Performance Laser Peening for Effective Mitigation of Stress Corrosion Cracking (open access)

High-Performance Laser Peening for Effective Mitigation of Stress Corrosion Cracking

Stress corrosion cracking (SCC) in the Yucca Mountain waste package closure welds is believed to be the greatest threat to long-term containment. Use of stress mitigation to eliminate tensile stresses resulting from welding can prevent SCC. A laser technology with sufficient average power to achieve high throughput has been developed and commercially deployed with high peak power and sufficiently high average power to be an effective laser peening system. An appropriately applied version of this process could be applied to eliminate SCC in the waste package closure welds.
Date: October 2, 2002
Creator: Hackel, L.; Hao-Lin, C.; Wong, F. & Hill, M.
System: The UNT Digital Library
Isotopic Tracing of Fuel Components in Particulate Emissions from Diesel Engines using Accelerator Mass Spectrometry (AMS) (open access)

Isotopic Tracing of Fuel Components in Particulate Emissions from Diesel Engines using Accelerator Mass Spectrometry (AMS)

Accelerator mass spectrometry (AMS) is an isotope-ratio measurement technique developed in the late 1970s for tracing long-lived radioisotopes (e.g., {sup 14}C half life = 5760 y). The technique counts individual nuclei rather than waiting for their radioactive decay, allowing measurement of more than 100 low-level {sup 14}C samples per day (Vogel et al, 1995). The LLNL AMS system is shown in Fig.1. The contemporary quantity of {sup 14}C in living things ({sup 14}C/C = 1.2 x 10{sup -12} or 110 fmol {sup 14}C/ g C) is highly elevated compared to the quantity of {sup 14}C in petroleum-derived products. This isotopic elevation is sufficient to trace the fate of bio-derived fuel components in the emissions of an engine without the use of radioactive materials. If synthesis of a fuel component from biologically-derived source material is not feasible, another approach is to purchase {sup 14}C-labeled material (e.g., dibutyl maleate (DBM)) and dilute it with petroleum-derived material to yield a contemporary level of {sup 14}C. In each case, the virtual absence of {sup 14}C in petroleum based fuels gives a very low {sup 14}C background that makes this approach to tracing fuel components practical. Regulatory pressure to significantly reduce the particulate emissions from …
Date: August 2, 2001
Creator: Buchholz, Bruce A.; Mueller, Charles J. & Garbak, John
System: The UNT Digital Library
Generalized Alvarez lens for correction of laser aberrations (open access)

Generalized Alvarez lens for correction of laser aberrations

The Alvarez lens (US Patent No. 3,305,294 [1]) is a compact aberration corrector. The original design emphasized in the patent consists of a pair of adjacent optical elements that provide a variable focus. A lens system with a variable effective focal length is nothing new. Such systems are widely used in cameras, for example. It is the compactness and simplicity of operation that is the key advantage of the Alvarez lens. All of the complexity is folded into the design and fabrication of the optical elements. As mentioned in the Alvarez patent [1] and elaborated upon in Palusinski et al. [2], if one is willing to fold even more complexity into the optical elements, it is possible to correct higher-order aberrations as well. There is no theoretical limit to the number or degree of wavefront distortions that can be corrected. The only limitation is that there must be a fixed relative magnitude of the aberrations. Independent correction of each component of the higher-order aberrations can not be performed without additional elements and degrees of freedom [3]. Under some circumstances, coupling may be observed between different aberrations. This can be mitigated with the appropriate choice of design parameters. New methods are …
Date: December 2, 2004
Creator: LaFortune, K N
System: The UNT Digital Library