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Texas Historically Underutilized Business Semi-Annual Report: 2000
Semi-annual report documenting statistics and analysis of contracts awarded to historically underutilized business (HUBs) by Texas state agencies, including procurement goals and performances,1999-2000 semi-annual total expenditure charts.
Date:
April 17, 2000
Creator:
Texas. General Services Commission.
Object Type:
Report
System:
The Portal to Texas History
Texas Racing Commission Annual Report: 2002
Annual report of the Texas Racing Commission describing goals, activities, and accomplishments during fiscal year 2002
Date:
June 17, 2002
Creator:
Texas Racing Commission
Object Type:
Report
System:
The Portal to Texas History
Texas Racing Commission Annual Report: 2001
Annual report of the Texas Racing Commission describing goals, activities, and accomplishments during fiscal year 2001
Date:
July 17, 2002
Creator:
Texas Racing Commission
Object Type:
Report
System:
The Portal to Texas History
Renewable Energy and Your Electric Utility
Bulletin describing Texans' desire to move towards renewable energy and the possibilities that energy offers.
Date:
June 17, 2003
Creator:
Texas. State Energy Conservation Office.
Object Type:
Pamphlet
System:
The Portal to Texas History
Metallization of Hydrogen and Other Small Molecules at 100 GPa Pressures
Fluid hydrogen, oxygen, and nitrogen become metallic at 100 GPa (1 Mbar) pressures. Disorder is the primary reason for observing a metal at lower pressures in the fluid than expected for the ordered solid. This metallic transition is similar to those observed in fluid Cs and Rb by Hensel et al. All five undergo a Mott transition from a semiconducting to metallic fluid with the same electrical conductivities. In contrast, water is a proton conductor at pressures up to 200 GPa. Extreme conditions were achieved for {approx}100 ns with a reverberating shock wave generated with a two-stage light-gas gun.
Date:
August 17, 2001
Creator:
Nellis, W J
Object Type:
Article
System:
The UNT Digital Library
Wet-Etch Figuring: Optical Surfacing by Controlled Application of Etchant Solution Using the marangoni Effect
Wet-etch figuring (WEF), a computer-controlled method for generating arbitrarily shaped optical surfaces using wet chemical etching, has been developed. This method uses applicator geometry and surface tension gradients (the Marangoni Effect) to define and confine the footprint of a wetted etchant zone on the surface. Capillary forces attach the flowing etchant solution to the underside of the optic being figured. No mechanical or thermal stresses or residues are applied to the optic by this process. This enables interferometric measurement of the glass thickness while surfacing, which then controls the placement and dwell time of the wetted zone. The result is a truly deterministic, closed-loop figuring process with a high degree of optical precision. This process can figure sub-millimeter thickness, large-aperture plates or sheets that are very difficult to finish by conventional methods. Automated linear and circular spot etching tools were used to demonstrate surfacing on 380 micron-thick glass sheets, to Strehl better than 0.8, as specified by data array or Zernike polynomials.
Date:
May 17, 2001
Creator:
Rushford, M. C.; Britten, J. A.; Hoaglan, C. R.; Thomas, I. M.; Summers, L. J. & Dixit, S. D.
Object Type:
Article
System:
The UNT Digital Library
PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP (VOLUME 55) COLLECTIVE FLOW AND QGP PROPERTIES.
The first three years of RHIC physics, with Au/Au collisions induced at 65, 130 and 200 GeV per nucleon pair, produced dramatic results, particularly with respect to collective observables such as transverse flow and anisotropies in transverse momentum spectra. It has become clear that the data show very strong rescattering at very early times of the reaction, strong enough in fact to be described by the hydrodynamic limit. Therefore, with today's experiments, we are able to investigate the equation of state of hot quark gluon matter, discuss its thermodynamic properties and relate them to experimental observables. At this workshop we came together to discuss our latest efforts both in the theoretical description of heavy ion collisions as well as most recent experimental results that ultimately allow us to extract information on the properties of RHIC matter. About 50 participants registered for the workshop, but many more dropped in from the offices at BNL. The workshop lasted for three days, of which each day was assigned a special topic on which the talks focused. On the first day we dealt with the more general question what the strong collective phenomena observed in RHIC collisions tell us about the properties and the …
Date:
November 17, 2003
Creator:
BASS,S. ESUMI,S. HEINZ,U. KOLB,P. SHURYAK,E. XU,N.
Object Type:
Report
System:
The UNT Digital Library
Structured Extended Finite Element Methods of Solids Defined by Implicit Surfaces
A paradigm is developed for generating structured finite element models from solid models by means of implicit surface definitions. The implicit surfaces are defined by radial basis functions. Internal features, such as material interfaces, sliding interfaces and cracks are treated by enrichment techniques developed in the extended finite element method (X-FEM). Methods for integrating the weak form for such models are proposed. These methods simplify the generation of finite element models. Results presented for several examples show that the accuracy of this method is comparable to standard unstructured finite element methods.
Date:
November 17, 2002
Creator:
Belytschko, T; Mish, K; Moes, N & Parimi, C
Object Type:
Report
System:
The UNT Digital Library
A Non-Electrostatic Surface Complexation Approach to Modeling Radionuclide Migration at the Nevada Test Site: I. Iron Oxides and Calcite
Reliable quantitative prediction of contaminant transport in subsurface environments is critical to evaluating the risks associated with radionuclide migration. As part of the Underground Test Area (UGTA) project, radionuclide transport away from various underground nuclear tests conducted in the saturated zone at the Nevada Test Site (NTS) is being examined. In the near-field environment, reactive transport simulations must account for changes in water chemistry and mineralogy as a function of time and their effect on radionuclide migration. Unlike the K{sub d} approach, surface complexation (SC) reactions, in conjunction with ion exchange and precipitation, can be used to describe radionuclide reactive transport as a function of changing environmental conditions. They provide a more robust basis for describing radionuclide retardation in geochemically dynamic environments. The interaction between several radionuclides considered relevant to the UGTA project and iron oxides and calcite are examined in this report. The interaction between these same radionuclides and aluminosilicate minerals is examined in a companion report (Zavarin and Bruton, 2004). Selection criteria for radionuclides were based on abundance, half-life, toxicity to human and environmental health, and potential mobility at NTS (Tompson et al., 1999). Both iron oxide and calcite minerals are known to be present at NTS in …
Date:
December 17, 2004
Creator:
Zavarin, M & Bruton, C J
Object Type:
Report
System:
The UNT Digital Library
A neutron sensor based on synthetic single crystal diamond
We report the first neutron data for a single crystal Chemical Vapor Deposition (CVD) diamond sensor. Results are presented for 2.5, 14.1, and 14.9 MeV incident neutrons. We show that the energy resolution for 14.1 MeV neutrons is at least 2.9% (as limited by the energy spread of the incident neutrons), and perhaps as good as 0.4% (as extrapolated from high resolution {alpha} particle data). This result could be relevant to fusion neutron spectroscopy at machines like the International Thermonuclear Experimental Reactor (ITER). We also show that our sensor has a high neutron linear attenuation coefficient, due to the high atomic density of diamond, and this could lead to applications in fission neutron detection.
Date:
October 17, 2003
Creator:
Schmid, G. J.; Koch, J. A.; Lerche, R. A. & Moran, M. J.
Object Type:
Article
System:
The UNT Digital Library
Detection of Topological Patterns in Protein Networks.
Complex networks appear in biology on many different levels: (1) All biochemical reactions taking place in a single cell constitute its metabolic network, where nodes are individual metabolites, and edges are metabolic reactions converting them to each other. (2) Virtually every one of these reactions is catalyzed by an enzyme and the specificity of this catalytic function is ensured by the key and lock principle of its physical interaction with the substrate. Often the functional enzyme is formed by several mutually interacting proteins. Thus the structure of the metabolic network is shaped by the network of physical interactions of cell's proteins with their substrates and each other. (3) The abundance and the level of activity of each of the proteins in the physical interaction network in turn is controlled by the regulatory network of the cell. Such regulatory network includes all of the multiple mechanisms in which proteins in the cell control each other including transcriptional and translational regulation, regulation of mRNA editing and its transport out of the nucleus, specific targeting of individual proteins for degradation, modification of their activity e.g. by phosphorylation/dephosphorylation or allosteric regulation, etc. To get some idea about the complexity and interconnectedness of protein-protein regulations …
Date:
November 17, 2003
Creator:
Maslov, S. & Sneppen, K.
Object Type:
Book
System:
The UNT Digital Library
Comment on ''Sensitivity Analysis and Determination of Streambed Leakance and Aquifer Hydraulic Properties'' by Xunhong Chen and Xi Chen, Journal of Hydrology, 2003, v.284, 270-284
Recently, studies of the Platte River watershed have gained significant attention from federal and Nebraska, USA, state agencies due to the importance of groundwater/surface-water interactions under drought conditions. Using archive data from a 1983 pumping test, Chen and Chen (2003) interpret the hydraulic properties of the alluvium and a streambed of the Platte River near Kearney, Nebraska, and compare their data with results of other studies performed over the past several years. Three important inconsistencies of this article will be highlighted here: (1) misuse of the analytical model of Hunt (1999), (2) departure of their results from previously published data, and (3) unsatisfactory explanation of these anomalous results.
Date:
May 17, 2004
Creator:
Kollet, S
Object Type:
Article
System:
The UNT Digital Library
Molecular Dynamics Simulations of Coulomb Explosion
A swift ion creates a track of electronic excitations in the target material. A net repulsion inside the track can cause a ''Coulomb Explosion'', which can lead to damage and sputtering of the material. Here we report results from molecular-dynamics (MD) simulations of Coulomb explosion for a cylindrical track as a function of charge density and neutralization/quenching time, {tau}. Screening by the free electrons is accounted for using a screened Coulomb potential for the interaction among charges. The yield exhibits a prompt component from the track core and a component, which dominates at higher excitation density, from the heated region produced. For the cases studied, the number of atoms ejected per incident ion, i.e. the sputtering yield Y, is quadratic with charge density along the track as suggested by simple models. Y({tau} = 0.2 Debye periods) is nearly 20% of the yield when there is no neutralization ({tau} {yields} {infinity}). The connections between ''Coulomb explosions'', thermal spikes and measurements of electronic sputtering are discussed.
Date:
May 17, 2002
Creator:
Bringa, E M
Object Type:
Article
System:
The UNT Digital Library
Correlated Nitrogen and Carbon Anomalies in an Anhydrous Interplanetary Dust Particle - Implications for Extraterrestrial Organic Matter Accreted by the Prebiotic Earth
Given the ubiquitous presence of H and N isotopic anomalies in interplanetary dust particles (IDPs) and their probable association with carbonaceous material, the lack of similar isotopic anomalies in C has been a major conundrum. We report here the first observation of correlated N and C isotopic anomalies in organic matter within an anhydrous IDP. The {sup 15}N composition of the anomalous region is the highest seen to date in an IDP and is accompanied by a moderate depletion in {sup 13}C. Our observations establish the presence of hetero-atomic organic compounds of presolar origin among the constant flux of carbonaceous material accreting to the terrestrial planets within IDPs. Theoretical models suggest that low temperature formation of organic compounds in cold interstellar molecular clouds does produce C and N fractionations, but it remains to be seen if these models can reproduce the specific effects we observe here.
Date:
December 17, 2003
Creator:
Floss, C; Stadermann, F J; Bradley, J P; Dai, Z; Bajt, S & Graham, G
Object Type:
Article
System:
The UNT Digital Library
Electromagnetic Imaging of CO2 Sequestration at an Enhanced-Oil-Recovery Site
None
Date:
February 17, 2004
Creator:
Kirkendall, B. & Roberts, J.
Object Type:
Report
System:
The UNT Digital Library
Tool Gear: Infrastructure for Parallel Tools
Tool Gear is a software infrastructure for developing performance analysis and other tools. Unlike existing integrated toolkits, which focus on providing a suite of capabilities, Tool Gear is designed to help tool developers create new tools quickly. It combines dynamic instrumentation capabilities with an efficient database and a sophisticated and extensible graphical user interface. This paper describes the design of Tool Gear and presents examples of tools that have been built with it.
Date:
April 17, 2003
Creator:
May, J & Gyllenhaal, J
Object Type:
Article
System:
The UNT Digital Library
Theoretical Progress for the Associated Production of a Higgs Boson With Heavy Quarks at Hadron Colliders.
The production of a Higgs boson in association with a pair of t{bar t} or b{bar b} quarks plays a very important role at both the Tevatron and the Large Hadron Collider. The theoretical prediction of the corresponding cross sections has been improved by including the complete next-to-leading order QCD corrections. After a brief introduction, we review the results obtained for both the Tevatron and the Large Hadron Collider.
Date:
July 17, 2003
Creator:
Dawson, S.; Jackson, C. B.; Orr, L. H.; Reina, L. & Wackeroth, D.
Object Type:
Article
System:
The UNT Digital Library
NADS - Nuclear And Atomic Data System
We have developed NADS (Nuclear and Atomic Data System), a web-based graphical interface for viewing pointwise and grouped cross-sections and distributions. Our implementation is a client / server model. The client is a Java applet that displays the graphical interface, which has interactive 2-D, 3-D, and 4-D plots and tables. The server, which can serve and perform computations the data, has been implemented in Python using the FUDGE package developed by Bret Beck at LLNL. Computational capabilities include algebraic manipulation of nuclear evaluated data in databases such as LLNL's ENDL-99, ENDF/B-V and ENDF/B-VI as well as user data. Processed data used in LLNL's transport codes are accessible as well. NADS is available from http://nuclear.llnl.gov/
Date:
September 17, 2004
Creator:
McKinley, M S; Beck, B & McNabb, D
Object Type:
Article
System:
The UNT Digital Library
Moment Magnitude Calibration for the Eastern Mediterranean Region from Broadband Regional Coda Envelopes
The following is an overview of results from ROA01-32 that focuses on an empirical method of calibrating stable seismic source moment-rate spectra derived from regional coda envelopes using broadband stations. The main goal was to develop a regional magnitude methodology that had the following properties: (1) it is tied to an absolute scale and is thus unbiased and transportable; (2) it can be tied seamlessly to the well-established teleseismic and regional catalogs; (3) it is applicable to small events using a sparse network of regional stations; (4) it is flexible enough to utilize S{sub n}-coda, L{sub g}-coda, or P-coda, whichever phase has the best signal-to-noise ratio. The results of this calibration yield source spectra and derived magnitudes that were more stable than any other direct-phase measure to date. Our empirical procedure accounted for all propagation, site, and S-to-coda transfer function effects. The resultant coda-derived moment-rate spectra were used to provide traditional band-limited magnitude (e.g., M{sub L}, m{sub b} etc.) as well as an unbiased, unsaturated magnitude (moment magnitude, M{sub w}) that is tied to a physical measure of earthquake size (i.e., seismic moment). We validated our results by comparing our coda-derived moment estimates with those obtained from long-period waveform modeling. …
Date:
July 17, 2003
Creator:
Mayeda, K; Eken, T; Hofstetter, A; Turkelli, N; O'Boyle, J; Orgulu, G et al.
Object Type:
Article
System:
The UNT Digital Library
Flame Inhibition by Phosphorus-Containing Compounds over a Range of Equivalence Ratios
There is much interest in the combustion mechanism of organophosphorus compounds (OPCs) due to their role as potential halon replacements in fire suppression. A continuing investigation of the inhibition activity of organophosphorus compounds under a range of equivalence ratios was performed experimentally and computationally, as measured by the burning velocity. Updates to a previous mechanism were made by the addition and modification of reactions in the mechanism for a more complete description of the recombination reactions. In this work, the laminar flame speed is measured experimentally and calculated numerically for a premixed propane/air flame, under a range of equivalence ratios, undoped and doped with dimethyl methylphosphonate (DMMP). A detailed investigation of the catalytic cycles involved in the recombination of key flame radicals is made for two equivalence ratios, lean and rich. From this, the importance of different catalytic cycles involved in the lean versus rich case is discussed. Although the importance of certain cycles is different under different stoichiometries, the OPCs are similarly effective across the range, demonstrating the robustness of OPCs as flame suppressants. In addition, it is shown that the phosphorus compounds are most active in the high temperature region of the flame. This may, in part, explain …
Date:
March 17, 2004
Creator:
Jayaweera, T M; Melius, C F; Pitz, W J; Westbrook, C K; Korobeinichev, O P; Shvartsberg, V M et al.
Object Type:
Article
System:
The UNT Digital Library
Nonradiological Environmental Report Maamora Site, Morocco
Under the Sister Laboratory Arrangement between Lawrence Livermore National Laboratory (LLNL) and the Moroccan National Center for Nuclear Energy Sciences and Techniques (CNESTEN), environmental sampling and analysis were performed to assess the background concentrations of nonradiological constituents in various environmental media at the Maamora Forest CNESTEN Laboratory Site. Samples were collected from surface soil, surface water and groundwater wells, short-lived vegetation (mainly native grass), and long-lived vegetation (cork oak). Samples were collected inside the property fence line, in the buffer zone surrounding the site, and off site at water locations. The soil and vegetation samples were analyzed for metals and pesticides and screened for polychlorinated biphenyls (PCBs); the water samples were analyzed for metals, general minerals, and pesticides and screened for PCBs.
Date:
July 17, 2003
Creator:
Althouse, P E; Blake, R G; Bandong, B B; Belghit, H & Dehbi, N
Object Type:
Report
System:
The UNT Digital Library
Supersensitive in Situ Hybridization by Tyramide Signal Amplification and Nanogold Silver Staining: The Contribution of Autometallography and Catalyzed Reporter Deposition to the Rejuvenation of In Situ Hybridization
It is peculiar that in situ hybridization (ISH), a technique with many similarities to immunohistochemistry (IHC), has not enjoyed the phenomenal growth in both basic research and clinical applications as has its sister technique IHC. Since the late 1970s, when immunoperoxidase techniques began to be applied to routine diagnostic material and to numerous research applications, there has been a natural evolution of the IHC procedure. Namely, only a few primary antibodies were available commercially at the onset, and only one indirect and the peroxidase-antiperoxidase (PAP) technique detection systems were in place. With the advent of avidin-biotin detection systems and monoclonal antibodies, and a viable commercial market, extraordinary growth of the procedure's applications in clinical research and diagnostic pathology occurred during the subsequent two decades. Today, IHC is automated and widely used for research purposes and, to a large extent, has become a routine diagnostic ''special stain'' in most clinical laboratories. During the same period, ISH enjoyed very little growth in both research and diagnostic applications. What has accounted for this lack of maturation of the technique? The success of IHC is part of the reason measuring a gene's encoded protein routinely and inexpensively, particularly as automation evolved, rendered IHC a …
Date:
April 17, 2002
Creator:
Tubbs, Raymond R.; Pettay, James; Grogan, Thomas; Powell, R. D.; Cheung, Annie L. M.; Hainfeld, James et al.
Object Type:
Book
System:
The UNT Digital Library
Adaptive Optics Applications in Vision Science
Adaptive optics can be used to correct the aberrations in the human eye caused by imperfections in the cornea and the lens and thereby, improve image quality both looking into and out of the eye. Under the auspices of the NSF Center for Adaptive Optics and the DOE Biomedical Engineering Program, Lawrence Livermore National Laboratory has joined together with leading vision science researchers around the country to develop and test new ophthalmic imaging systems using novel wavefront corrector technologies. Results of preliminary comparative evaluations of these technologies in initial system tests show promise for future clinical utility.
Date:
March 17, 2003
Creator:
Olivier, S. S.
Object Type:
Article
System:
The UNT Digital Library
REGIONAL-SCALE WIND FIELD CLASSIFICATION EMPLOYING CLUSTER ANALYSIS
The classification of time-varying multivariate regional-scale wind fields at a specific location can assist event planning as well as consequence and risk analysis. Further, wind field classification involves data transformation and inference techniques that effectively characterize stochastic wind field variation. Such a classification scheme is potentially useful for addressing overall atmospheric transport uncertainty and meteorological parameter sensitivity issues. Different methods to classify wind fields over a location include the principal component analysis of wind data (e.g., Hardy and Walton, 1978) and the use of cluster analysis for wind data (e.g., Green et al., 1992; Kaufmann and Weber, 1996). The goal of this study is to use a clustering method to classify the winds of a gridded data set, i.e, from meteorological simulations generated by a forecast model.
Date:
June 17, 2004
Creator:
Glascoe, L G; Glaser, R E; Chin, H S & Loosmore, G A
Object Type:
Article
System:
The UNT Digital Library