Food Labeling: Allergy Information (open access)

Food Labeling: Allergy Information

This report provides background information on food allergies and review efforts to provide improved labeling information for food allergy sufferers.
Date: March 19, 2007
Creator: Porter, Donna V.
Object Type: Report
System: The UNT Digital Library
A Detailed Modeling Study of Propane Oxidation (open access)

A Detailed Modeling Study of Propane Oxidation

A detailed chemical kinetic mechanism has been used to simulate ignition delay times recorded by a number of experimental shock tube studies over the temperature range 900 {le} T {le} 1800 K, in the pressure range 0.75-40 atm and in the equivalence ratio range 0.5 {le} {phi} {le} 2.0. Flame speed measurements at 1 atm in the equivalence ratio range 0.4 {le} {phi} {le} 1.8 have also been simulated. Both of these data sets, particularly those recorded at high pressure, are of particular importance in validating a kinetic mechanism, as internal combustion engines operate at elevated pressures and temperatures and rates of fuel oxidation are critical to efficient system operation. Experiments in which reactant, intermediate and product species were quantitatively recorded, versus temperature in a jet-stirred reactor (JSR) and versus time in a flow reactor are also simulated. This data provide a stringent test of the kinetic mechanism as it must reproduce accurate quantitative profiles for all reactant, intermediate and product species. The JSR experiments were performed in the temperature range 1000-1110 K, in the equivalence ratio range 0.5 {le} {phi} {le} 4.0, at a pressure of 5 atm. These experiments are complemented by those carried out in a flow …
Date: March 19, 2004
Creator: Westbrook, C. K.; Jayaweera, T. M.; Pitz, W. J. & Curran, H. J.
Object Type: Article
System: The UNT Digital Library
The Corporation for National and Community Service: Overview of Programs and FY2009 Funding (open access)

The Corporation for National and Community Service: Overview of Programs and FY2009 Funding

This report provides an overview of each National and Community Service Act(NCSA) and Domestic Volunteer Service Act(DVSA) program and compares Corporation for National and Community Service(CNCS) funding from the FY2007 Appropriation, the FY2008 Appropriation, and the FY2009 budget request.
Date: March 19, 2008
Creator: Lordeman, Ann & Rudman, Abigail B.
Object Type: Report
System: The UNT Digital Library
Internet Domain Names: Background and Policy Issues (open access)

Internet Domain Names: Background and Policy Issues

None
Date: March 19, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
A crust and upper mantle model of Eurasia and North Africa for Pn travel time calculation (open access)

A crust and upper mantle model of Eurasia and North Africa for Pn travel time calculation

We develop a Regional Seismic Travel Time (RSTT) model and methods to account for the first-order effect of the three-dimensional crust and upper mantle on travel times. The model parameterization is a global tessellation of nodes with a velocity profile at each node. Interpolation of the velocity profiles generates a 3-dimensional crust and laterally variable upper mantle velocity. The upper mantle velocity profile at each node is represented as a linear velocity gradient, which enables travel time computation in approximately 1 millisecond. This computational speed allows the model to be used in routine analyses in operational monitoring systems. We refine the model using a tomographic formulation that adjusts the average crustal velocity, mantle velocity at the Moho, and the mantle velocity gradient at each node. While the RSTT model is inherently global and our ultimate goal is to produce a model that provides accurate travel time predictions over the globe, our first RSTT tomography effort covers Eurasia and North Africa, where we have compiled a data set of approximately 600,000 Pn arrivals that provide path coverage over this vast area. Ten percent of the tomography data are randomly selected and set aside for testing purposes. Travel time residual variance for …
Date: March 19, 2009
Creator: Myers, S; Begnaud, M; Ballard, S; Pasyanos, M; Phillips, W S; Ramirez, A et al.
Object Type: Article
System: The UNT Digital Library
Post-Closure Inspection Report for the Tonopah Test Range, Nevada, For Calendar Year 2008 (open access)

Post-Closure Inspection Report for the Tonopah Test Range, Nevada, For Calendar Year 2008

This report provides the results of the annual post-closure inspections conducted at the closed Corrective Action Unit (CAU) sites located on the Tonopah Test Range (TTR), Nevada. This report covers calendar year 2008 and includes inspection and repair activities completed at the following ten CAUs: #2; CAU 400: Bomblet Pit and Five Points Landfill (TTR) #2; CAU 404: Roller Coaster Lagoons and Trench (TTR) #2; CAU 407: Roller Coaster RadSafe Area (TTR) #2; CAU 423: Area 3 Underground Discharge Point, Building 0360 (TTR) #2; CAU 424: Area 3 Landfill Complexes (TTR) #2; CAU 426: Cactus Spring Waste Trenches (TTR) #2; CAU 427: Area 3 Septic Waste Systems 2, 6 (TTR) #2; CAU 453: Area 9 UXO Landfill (TTR) #2; CAU 484: Surface Debris, Waste Sites, and Burn Area (TTR) #2; CAU 487: Thunderwell Site (TTR)
Date: March 19, 2009
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Annealing as grown large volume CZT single crystals increased spectral resolution (open access)

Annealing as grown large volume CZT single crystals increased spectral resolution

The spectroscopic performance of current large-volume Cadmium 10% Zinc Telluride, Cd{sub 0.9}Zn{sub 0.1}Te, (CZT) detectors is impaired by cumulative effect of tellurium precipitates (secondary phases) presented in CZT single-crystal grown by low-pressure Bridgman techniques(1). This statistical effect may limit the energy resolution of large-volume CZT detectors (typically 2-5% at 662 keV for 12-mm thick devices). The stochastic nature of the interaction prevents the use of any electronic or digital charge correction techniques without a significant reduction in the detector efficiency. This volume constraint hampers the utility of CZT since the detectors are inefficient at detecting photons >1MeV and/or in low fluency situations. During the project, seven runs CZT ingots have been grown, in these ingots the indium dopant concentrations have been changed in the range between 0.5ppm to 6ppm. The I-R mapping imaging method has been employed to study the Te-precipitates. The Teprecipitates in as-grown CZT wafers, and after annealing wafers have been systematically studied by using I-R mapping system (home installed, resolution of 1.5 {micro}m). We employed our I-R standard annealing CZT (Zn=4%) procedure or two-steps annealing into radiation CZT (Zn=10%), we achieved the 'non'-Te precipitates (size < 1 {micro}m) CZT n+-type with resistivity > 10{sup 9-10} {Omega}-cm. We …
Date: March 19, 2008
Creator: Li, Dr. Longxia
Object Type: Report
System: The UNT Digital Library
Structural characterization of terrestrial microbial Mn oxides from Pinal Creek, AZ (open access)

Structural characterization of terrestrial microbial Mn oxides from Pinal Creek, AZ

The microbial catalysis of Mn(II) oxidation is believed to be a dominant source of abundant sorption- and redox-active Mn oxides in marine, freshwater, and subsurface aquatic environments. In spite of their importance, environmental oxides of known biogenic origin have generally not been characterized in detail from a structural perspective. Hyporheic zone Mn oxide grain coatings at Pinal Creek, Arizona, a metals-contaminated stream, have been identified as being dominantly microbial in origin and are well studied from bulk chemistry and contaminant hydrology perspectives. This site thus presents an excellent opportunity to study the structures of terrestrial microbial Mn oxides in detail. XRD and EXAFS measurements performed in this study indicate that the hydrated Pinal Creek Mn oxide grain coatings are layer-type Mn oxides with dominantly hexagonal or pseudo-hexagonal layer symmetry. XRD and TEM measurements suggest the oxides to be nanoparticulate plates with average dimensions on the order of 11 nm thick x 35 nm diameter, but with individual particles exhibiting thickness as small as a single layer and sheets as wide as 500 nm. The hydrated oxides exhibit a 10-A basal-plane spacing and turbostratic disorder. EXAFS analyses suggest the oxides contain layer Mn(IV) site vacancy defects, and layer Mn(III) is inferred …
Date: March 19, 2008
Creator: Bargar, John; Fuller, Christopher; Marcus, Matthew A.; Brearley, Adrian J.; Perez De la Rosa, M.; Webb, Samuel M. et al.
Object Type: Article
System: The UNT Digital Library
The Davis-Bacon Act: Issues and Legislation During the 108th Congress (open access)

The Davis-Bacon Act: Issues and Legislation During the 108th Congress

This report discusses the debate surrounding the Davis-Bacon Act (1931, as amended), which requires, among other things, that not less than the locally-prevailing wage be paid to workers employed in federal contract construction. Through recent decades, the Act has become a continuing source of contention, particularly regarding its impacts, whether it should be modified, strengthened, or repealed, and if it is being administered effectively.
Date: March 19, 2004
Creator: Whittaker, William G.
Object Type: Report
System: The UNT Digital Library
The Hierarchical Build-Up of Massive Galaxies And the Intracluster Light Since z=1 (open access)

The Hierarchical Build-Up of Massive Galaxies And the Intracluster Light Since z=1

We use a set of simulation-based models for the dissipationless evolution of galaxies since z = 1 to constrain the fate of accreted satellites embedded in dark matter subhalos. These models assign stellar mass to dark matter halos at z = 1 by relating the observed galaxy stellar mass function (GSMF) to the halo+subhalo mass function monotonically. The evolution of the stellar mass content is then followed using halo merger trees extracted from N-body simulations. Our models are differentiated only in the fate assigned to satellite galaxies once subhalos, within which satellites are embedded, disrupt. These models are confronted with the observed evolution in the massive end of the GSMF, the z {approx} 0 brightest cluster galaxy (BCG)-cluster mass relation, and the combined BCG and intracluster light (ICL) luminosity distribution--all observables expected to evolve approximately dissipationlessly since z = 1. The combined observational constraints favor a model in which the vast majority ({approx}> 80%) of satellite stars from disrupted subhalos go into the ICL (operationally defined here as light below a surface brightness cut of {mu}{sub i} {approx} 23mag arcsec{sup -2}). Conversely, models that leave behind a significant population of satellite galaxies once the subhalo has disrupted are strongly disfavored, …
Date: March 19, 2007
Creator: Conroy, Charlie; Wechsler, Risa H. & Kravtsov, Andrey V.
Object Type: Article
System: The UNT Digital Library
Development of a Simple Radioactive marker System to Reduce Positioning Errors in Radiation Treatment (open access)

Development of a Simple Radioactive marker System to Reduce Positioning Errors in Radiation Treatment

The objective of this research is to implement an inexpensive, quick and simple monitor that provides an accurate indication of proper patient position during the treatment of cancer by external beam X-ray radiation and also checks for any significant changes in patient anatomy. It is believed that this system will significantly reduce the treatment margin, provide an additional, independent quality assurance check of positioning accuracy prior to all treatments and reduce the probability of misadministration of therapeutic dose.
Date: March 19, 2007
Creator: Miller, William H. & Palta, Dr. Jatinder
Object Type: Report
System: The UNT Digital Library
Early Computing and Its Impact on Lawrence Livermore National Laboratory (open access)

Early Computing and Its Impact on Lawrence Livermore National Laboratory

None
Date: March 19, 2007
Creator: Lokke, W.
Object Type: Report
System: The UNT Digital Library
A Symposium in Honor of William A. Lester, Jr. on His 70thBirthday (open access)

A Symposium in Honor of William A. Lester, Jr. on His 70thBirthday

None
Date: March 19, 2007
Creator: Lester, William A., Jr.
Object Type: Article
System: The UNT Digital Library
Applications of Cfd Method to Gas Mixing Analysis in a Large-Scaled Tank (open access)

Applications of Cfd Method to Gas Mixing Analysis in a Large-Scaled Tank

The computational fluid dynamics (CFD) modeling technique was applied to the estimation of maximum benzene concentration for the vapor space inside a large-scaled and high-level radioactive waste tank at Savannah River site (SRS). The objective of the work was to perform the calculations for the benzene mixing behavior in the vapor space of Tank 48 and its impact on the local concentration of benzene. The calculations were used to evaluate the degree to which purge air mixes with benzene evolving from the liquid surface and its ability to prevent an unacceptable concentration of benzene from forming. The analysis was focused on changing the tank operating conditions to establish internal recirculation and changing the benzene evolution rate from the liquid surface. The model used a three-dimensional momentum coupled with multi-species transport. The calculations included potential operating conditions for air inlet and exhaust flows, recirculation flow rate, and benzene evolution rate with prototypic tank geometry. The flow conditions are assumed to be fully turbulent since Reynolds numbers for typical operating conditions are in the range of 20,000 to 70,000 based on the inlet conditions of the air purge system. A standard two-equation turbulence model was used. The modeling results for the typical …
Date: March 19, 2007
Creator: Lee, S. & Richard Dimenna, R.
Object Type: Article
System: The UNT Digital Library
The Molecular Basis for Metabolic and Energetic Diversity (open access)

The Molecular Basis for Metabolic and Energetic Diversity

We have used experimental and computational analysis of R. sphaeroides photosynthesis and other gene expression networks (Kaplan, Gomelsky, Donohue) (3-9, 12, 13, 15-18, 20). We have identified many new candidate photosynthesis genes with expression patterns that varied as a function of light intensity. Results from these experiments suggest there are many more light-regulated aspects of the photosynthetic lifestyle of this bacterium than previously appreciated. Ongoing genetic analysis confirms that mutations in some of these newly-identified photosynthesis block the ability of cells to use solar energy in the laboratory. We also carried out transcriptome and computational analysis of individual R. sphaeroides regulons. This identified additional genes that are directly regulated by individual transcription factors and refined the consensus sequence for master regulators of photosystem development. We also showed that PpsR indirectly regulates genes that do not contain the PpsR-binding sites, e.g. puf and puhA operons. This suggests that PpsR plays a more global role as a regulator of photosystem development than what was assumed before. A similar computational and microarray analysis of PrrA target genes has identified many new candidate promoters that are controlled by this master regulator of photosynthesis. We have begun bioinformatic, genetic and biochemical experiments aimed at elucidating …
Date: March 19, 2007
Creator: Timothy Donohue, PI
Object Type: Report
System: The UNT Digital Library
CHEMICAL STORAGE: MYTHS VERSUS REALITY (open access)

CHEMICAL STORAGE: MYTHS VERSUS REALITY

A large number of resources explaining proper chemical storage are available. These resources include books, databases/tables, and articles that explain various aspects of chemical storage including compatible chemical storage, signage, and regulatory requirements. Another source is the chemical manufacturer or distributor who provides storage information in the form of icons or color coding schemes on container labels. Despite the availability of these resources, chemical accidents stemming from improper storage, according to recent reports (1) (2), make up almost 25% of all chemical accidents. This relatively high percentage of chemical storage accidents suggests that these publications and color coding schemes although helpful, still provide incomplete information that may not completely mitigate storage risks. This manuscript will explore some ways published storage information may be incomplete, examine the associated risks, and suggest methods to help further eliminate chemical storage risks.
Date: March 19, 2007
Creator: Simmons, F
Object Type: Article
System: The UNT Digital Library
Friction Factor Measurements in an Equally Spaced Triangular Tube Array (open access)

Friction Factor Measurements in an Equally Spaced Triangular Tube Array

Friction factor data for adiabatic cross-flow of water in a staggered tube array was obtained over a Reynolds number range (based on hydraulic diameter and gap velocity) of about 10,000 to 250,000. The tubes were 12.7mm (0.5 inch) outer diameter, in a uniformly spaced triangular arrangement with a pitch-to-diameter ratio of 1.5. The friction factor was compared to several literature correlations, and was found to be best matched by the Idelchik correlation. Other correlations were found to vary significantly from the test data. Based on the test data, a new correlation is proposed for this tube bundle geometry which covers the entire Reynolds number range tested.
Date: March 19, 2007
Creator: Vassallo P, Symolon P
Object Type: Report
System: The UNT Digital Library
Studies of Hydrogen Getter Material Self-decomposition and Reaction Capacity (open access)

Studies of Hydrogen Getter Material Self-decomposition and Reaction Capacity

Diacetylene based hydrogen getters are examined in order to gauge their self decomposition products, as well as to determine possible origins for observed losses in origins getter capacity. Simple long term (several months) thermal aging tests were conducted, with periodic solid solid-phase micro micro-extraction (SPME) sampling followed by GC/MS analysis. The results suggest that bis(diphenylethynyl) benzene tends to decompose to give phenyl contaminants more readily than diphenylbutadiyne. Transmission electron microscopy (TEM) and electron diffraction studies of the palladium catalyst following varying extents of reaction with hydrogen show that there is no change to the catalyst particles, indicating that any change in capacity originates from other causes. These causes are suggested by Sievert's-type experiments on the reaction of the getter with a low pressure (about 10 Torr) hydrogen atmosphere. The reaction data indicate that the getter capacity depends on the pressure of hydrogen to which the material is exposed, and also its thermal history.
Date: March 19, 2007
Creator: Saab, A P & Dinh, L N
Object Type: Report
System: The UNT Digital Library
Tandem Filter Development for Thermophotovoltaic Energy Conversion from January 2003 to February 2006 (open access)

Tandem Filter Development for Thermophotovoltaic Energy Conversion from January 2003 to February 2006

The intent of this report is to summarize the tandem filter development for spectral control of thermophotovoltaic energy conversion from January 2003 to the termination of the program in February 2006 and to closeout tandem filter development in order to capture the knowledge gained from the development effort. Over the last three years, the goals of the tandem filter development have been the following: (1) Study the limits of the design of the interference optical coatings component of a tandem filter in order to develop higher performance designs; (2) Enhance the fabrication process of the optical interference coatings to increase the fidelity with the intended design and allow more complex, higher performing designs; (3) Support TPV module testing by providing tandem filters and assembly assistance; (4) Identify and develop materials for optical interference coatings that are stable at higher temperatures than current materials; and (5) Improve the understanding of the directional and spectral reflectance and transmittance characterization of the completed tandem filters to insure the veracity of the characterization data and to provide useful feedback to the tandem filter development process. This development effort has been a collaboration between KAPL and its contracted development partner, Rugate Technologies Inc.
Date: March 19, 2007
Creator: PM, Fourspring
Object Type: Report
System: The UNT Digital Library
Interim Letter Report - Verification Survey of Partial Grids H19, J21, J22, X20, and X21 at the David Witherspoon, Inc. 1630 Site, Knoxville Tennessee (open access)

Interim Letter Report - Verification Survey of Partial Grids H19, J21, J22, X20, and X21 at the David Witherspoon, Inc. 1630 Site, Knoxville Tennessee

Conduct verification surveys of available grids at the David Witherspoon Incorporated 1630 Site (DWI 1630) in Knoxville, Tennessee. The IVT conducted verification activities of partial grids H19, J21, J22, X20, and X21.
Date: March 19, 2008
Creator: Weaver, P. C.
Object Type: Report
System: The UNT Digital Library
Suppression of Type-I ELMs Using a Single Toroidal Row of Magnetic Field Perturbation Coils in DIII-D (open access)

Suppression of Type-I ELMs Using a Single Toroidal Row of Magnetic Field Perturbation Coils in DIII-D

None
Date: March 19, 2008
Creator: Fenstermacher, M. E.; Evans, T. E.; Osborne, T. H.; Schaffer, M. J.; deGrassie, J. S.; Gohil, P. et al.
Object Type: Article
System: The UNT Digital Library
Computational Models of X-Ray Burst Quenching Times and 12C Nucleosynthesis Following a Superburst (open access)

Computational Models of X-Ray Burst Quenching Times and 12C Nucleosynthesis Following a Superburst

Superbursts are energetic events on neutron stars that are a thousand times more powerful than ordinary type I X-ray bursts. They are believed to be powered by a thermonuclear explosion of accumulated {sup 12}C. However, the source of this {sup 12}C remains elusive to theoretical calculations and its concentration and ignition depth are both unknown. Here we present the first computational simulations of the nucleosynthesis during the thermal decay of a superbust, where X-ray bursts are quenched. Our calculations of the quenching time verify previous analytical calculations and shed new light on the physics of stable burning at low accretion rates. We show that concentrated (X{sub {sup 12}C} {approx}> 0.40), although insufficient, amounts of {sup 12}C are generated during the several weeks following the superburst where the decaying thermal flux of the superburst stabilizes the burning of the accreted material.
Date: March 19, 2009
Creator: Fisker, J L
Object Type: Report
System: The UNT Digital Library
High resolution fossil fuel combustion CO2 emission fluxes for the United States (open access)

High resolution fossil fuel combustion CO2 emission fluxes for the United States

Quantification of fossil fuel CO{sub 2} emissions at fine space and time resolution is emerging as a critical need in carbon cycle and climate change research. As atmospheric CO{sub 2} measurements expand with the advent of a dedicated remote sensing platform and denser in situ measurements, the ability to close the carbon budget at spatial scales of {approx}100 km{sup 2} and daily time scales requires fossil fuel CO{sub 2} inventories at commensurate resolution. Additionally, the growing interest in U.S. climate change policy measures are best served by emissions that are tied to the driving processes in space and time. Here we introduce a high resolution data product (the 'Vulcan' inventory: www.purdue.edu/eas/carbon/vulcan/) that has quantified fossil fuel CO{sub 2} emissions for the contiguous U.S. at spatial scales less than 100 km{sup 2} and temporal scales as small as hours. This data product, completed for the year 2002, includes detail on combustion technology and 48 fuel types through all sectors of the U.S. economy. The Vulcan inventory is built from the decades of local/regional air pollution monitoring and complements these data with census, traffic, and digital road data sets. The Vulcan inventory shows excellent agreement with national-level Department of Energy inventories, despite …
Date: March 19, 2009
Creator: Gurney, Kevin R.; Mendoza, Daniel L.; Zhou, Yuyu; Fischer, Marc L.; Miller, Chris C.; Geethakumar, Sarath et al.
Object Type: Article
System: The UNT Digital Library
Electron avalanches in liquid argon mixtures (open access)

Electron avalanches in liquid argon mixtures

We have observed stable avalanche gain in liquid argon when mixed with small amounts of xenon in the high electric field (>7 MV/cm) near the point of a chemically etched needle in a point-plane geometry. We identify two gain mechanisms, one pressure dependent, and the other independent of the applied pressure. We conclude that the pressure dependent signals are from avalanche gain in gas bubbles at the tip of the needle, while the pressure independent pulses are from avalanche gain in liquid. We measure the decay time spectra of photons from both types of avalanches. The decay times from the pressure dependent pulses decrease (increase) with the applied pressure (high voltage), while the decay times from the pressure independent pulses are approximately independent of pressure or high voltage. For our operating conditions, the collected charge distribution from avalanches is similar for 60 keV or 122 keV photon sources. With krypton additives, instead of Xe, we measure behavior consistent with only the pressure dependent pulses. Neon and TMS were also investigated as additives, and designs for practical detectors were tested.
Date: March 19, 2004
Creator: Kim, J. G.; Dardin, S. M.; Kadel, R. W.; Kadyk, J. A.; Wenzel, W. B. & Peskov, V.
Object Type: Article
System: The UNT Digital Library