Brazil-U.S. Relations (open access)

Brazil-U.S. Relations

This report analyzes Brazil's political, economic, and social conditions, and how those conditions affect its role in the region and its relationship with the United States.
Date: August 18, 2009
Creator: Meyer, Peter J. & Seelke, Clare Ribando
Object Type: Report
System: The UNT Digital Library
Effects of non-equilibrium particle distributions in deuterium-tritium burning (open access)

Effects of non-equilibrium particle distributions in deuterium-tritium burning

We investigate the effects of non-equilibrium particle distributions resulting from rapid deuterium-tritium burning in plasmas using a Fokker-Planck code that incorporates small-angle Coulomb scattering, Brehmsstrahlung, Compton scattering, and thermal-nuclear burning. We find that in inertial confinement fusion environments, deviations away from Maxwellian distributions for either deuterium or tritium ions are small and result in 1% changes in the energy production rates. The deuterium and tritium effective temperatures are not equal, but differ by only about 2.5% near the time of peak burn rate. Simulations with high Z (Xe) dopants show that the dopant temperature closely tracks that of the fuel. On the other hand, fusion product ion distributions are highly non-Maxwellian, and careful treatments of energy-exchange between these ions and other particles is important for determining burn rates.
Date: August 18, 2009
Creator: Michta, D; Graziani, F; Pruet, J & Luu, T
Object Type: Article
System: The UNT Digital Library
FLUOR HANFORDS APPROACH TO INTEGRATED SAFETY MANAGEMENT WORKER ENGAGEMENT 1996 - 2009 (open access)

FLUOR HANFORDS APPROACH TO INTEGRATED SAFETY MANAGEMENT WORKER ENGAGEMENT 1996 - 2009

None
Date: August 18, 2009
Creator: LD, ARNOLD
Object Type: Article
System: The UNT Digital Library
HANFORD DOUBLE-SHELL TANK THERMAL AND SEISMIC PROJECT DYTRAN ANALYSIS OF SEISMICALLY INDUCED FLUID-STRUCTURE INTERACTION IN A HANFORD DST PRIMARY TANK (open access)

HANFORD DOUBLE-SHELL TANK THERMAL AND SEISMIC PROJECT DYTRAN ANALYSIS OF SEISMICALLY INDUCED FLUID-STRUCTURE INTERACTION IN A HANFORD DST PRIMARY TANK

This report (Rev 1) incorporates corrections and clarifications regarding the interpretation of solutions in BNL (1995) per reviewer comments from a June 7-8, 2007 review meeting. The review comments affect Appendixes C and D of this report - the body of the report is unchanged.
Date: August 18, 2009
Creator: Mackey, T. C.; Abatt, F. G. & Rinker, M. W.
Object Type: Report
System: The UNT Digital Library
HANFORD DOUBLE-SHELL TANK THERMAL AND SEISMIC PROJECT DYTRAN BENCHMARK ANALYSIS OF SEISMICALLY INDUCED FLUID-STRUCTURE INTERACTION IN FLAT-TOP TANKS (open access)

HANFORD DOUBLE-SHELL TANK THERMAL AND SEISMIC PROJECT DYTRAN BENCHMARK ANALYSIS OF SEISMICALLY INDUCED FLUID-STRUCTURE INTERACTION IN FLAT-TOP TANKS

Rev 1 of this report provides corrections and clarifications in response to reviewer comments arising during a project review meeting held June 7-8, 2007.
Date: August 18, 2009
Creator: Mackey, T. C.; Abatt, F. G. & Rinker, M. W,
Object Type: Report
System: The UNT Digital Library
Improved Synthesis of [Si6Cl14]2-Salts as Precursors for Si6H12and other Novel Silanes (open access)

Improved Synthesis of [Si6Cl14]2-Salts as Precursors for Si6H12and other Novel Silanes

The reaction of excess HSiCl{sub 3} with the aforementioned triamines led to the formation of [Si{sub 6}Cl{sub 14}]{sup 2-} containing salts in all instances. The isolated complex salts were characterized using FT-IR and elemental analysis. IR spectra of these compounds showed characteristic Si-H stretching modes around 2100cm{sup -1} due to the hexacoordinate silane cation and Si-Cl active modes near 528cm{sup -1} as a result of the cyclic dianion. Reaction yields and elemental analysis (CHN) of the salts are summarized in a table. The reaction of peralkylated triamines with HSiCl{sub 3} in dry CH{sub 2}Cl{sub 2} gives ionic compounds based upon the tetradecachlorocyclohexasilane dianion. Several substituted triamines(R{sub 2}NC{sub 2}H{sub 4}NR{prime}C{sub 2}H{sub 4}NR{sub 2}where R = R{prime} = Et, {sup n}Pr; R = Et, R{prime}= {sup n}Bu, {sup n}Hexyl, Benzyl) were examined for this reaction and N,N,N{prime},N{prime}-tetraethyl-N{sup {double_prime}}-benzyl-diethylenetriamine produced the best yields of [Si{sub 6}Cl{sub 14}]{sup 2-} salt at 23% based on the amine reagent. This improvement in yield could be attributed to the decreased nucleophilicity of the central amine through increased steric hindrance of the alkyl substituents. The overall consequence of this substituent variation study has revealed new reagents for the synthesis of [Si{sub 6}Cl{sub 14}]{sup 2-} salts and further demonstrated …
Date: August 18, 2009
Creator: Anderson, Kenneth; Dai, Xuliang; Nelson, Kendric; Schulz, Doug & Boudjouk, Philip
Object Type: Article
System: The UNT Digital Library
Iran Sanctions (open access)

Iran Sanctions

This report focuses on the United States' relationship with Iran and how the Obama Administration is handling prior administrations' economic sanctions against Iran. The Obama Administration's policy approach toward Iran has contrasted with the Bush Administration's by attempting to couple the imposition of sanctions to an active and direct U.S. effort to negotiate with Iran on the nuclear issue.
Date: August 18, 2009
Creator: Katzman, Kenneth
Object Type: Report
System: The UNT Digital Library
"Research to Improve the Efficacy of Captive Broodstock Programs and Advance Hatchery Reform Throughout the Columbia River Basin." [from the Abstract], 2008-2009 Progress Report. (open access)

"Research to Improve the Efficacy of Captive Broodstock Programs and Advance Hatchery Reform Throughout the Columbia River Basin." [from the Abstract], 2008-2009 Progress Report.

This project was developed to conduct research to improve the efficacy of captive broodstock programs and advance hatchery reform throughout the Columbia River Basin. The project has three objectives: (1) maintain adaptive life history characteristics in Chinook salmon, (2) improve imprinting in juvenile sockeye salmon, and (3) match wild phenotypes in Chinook and sockeye salmon reared in hatcheries. A summary of the results are as follows: Objective 1: The ratio of jack to adult male Chinook salmon were varied in experimental breeding populations to test the hypothesis that reproductive success of the two male phenotypes would vary with their relative frequency in the population. Adult Chinook salmon males nearly always obtained primary access to nesting females and were first to enter the nest at the time of spawning. Jack male spawning occurred primarily by establishing satellite positions downstream of the courting pair, and 'sneaking' into the nest at the time of spawning. Male dominance hierarchies were fairly stable and strongly correlated with the order of nest entry at the time of spawning. Observed participation in spawning events and adult-to-fry reproductive success of jack and adult males was consistent with a negative frequency-dependent selection model. Overall, jack males sired an average …
Date: August 18, 2009
Creator: Berejikian, Barry A.
Object Type: Report
System: The UNT Digital Library
Single crystalline mesoporous silicon nanowires (open access)

Single crystalline mesoporous silicon nanowires

Herein we demonstrate a novel electroless etching synthesis of monolithic, single-crystalline, mesoporous silicon nanowire arrays with a high surface area and luminescent properties consistent with conventional porous silicon materials. The photoluminescence of these nanowires suggest they are composed of crystalline silicon with small enough dimensions such that these arrays may be useful as photocatalytic substrates or active components of nanoscale optoelectronic devices. A better understanding of this electroless route to mesoporous silicon could lead to facile and general syntheses of different narrow bandgap semiconductor nanostructures for various applications.
Date: August 18, 2009
Creator: Hochbaum, Allon; Dargas, Daniel; Hwang, Yun Jeong & Yang, Peidong
Object Type: Article
System: The UNT Digital Library
The Strategic Petroleum Reserve: History, Perspectives, and Issues (open access)

The Strategic Petroleum Reserve: History, Perspectives, and Issues

This reports discusses the history and establishment of Strategic Petroleum Reserve (SPR), acquisition of crude oil for the SPR. It talks about the debate over the years regarding when should the SPR be used.
Date: August 18, 2009
Creator: Bamberger, Robert
Object Type: Report
System: The UNT Digital Library
The Americans with Disabilities Act (ADA): Allocation of Scarce Medical Resources During a Pandemic (open access)

The Americans with Disabilities Act (ADA): Allocation of Scarce Medical Resources During a Pandemic

This report examines selected proposed priorities in light of the nondiscrimination provisions of the Americans with Disabilities Act (ADA) and Section 504 of the Rehabilitation Act of 1973.
Date: August 18, 2008
Creator: Jones, Nancy Lee
Object Type: Report
System: The UNT Digital Library
Determination of NAD+ and NADH level in a Single Cell Under H2O2 Stress by Capillary Electrophoresis (open access)

Determination of NAD+ and NADH level in a Single Cell Under H2O2 Stress by Capillary Electrophoresis

A capillary electrophoresis (CE) method is developed to determine both NAD{sup +} and NADH levels in a single cell, based on an enzymatic cycling reaction. The detection limit can reach down to 0.2 amol NAD{sup +} and 1 amol NADH on a home-made CE-LIF setup. The method showed good reproducibility and specificity. After an intact cell was injected into the inlet of a capillary and lysed using a Tesla coil, intracellular NAD{sup +} and NADH were separated, incubated with the cycling buffer, and quantified by the amount of fluorescent product generated. NADH and NAD{sup +} levels of single cells of three cell lines and primary astrocyte culture were determined using this method. Comparing cellular NAD{sup +} and NADH levels with and without exposure to oxidative stress induced by H{sub 2}O{sub 2}, it was found that H9c2 cells respond to the stress by reducing both cellular NAD{sup +} and NADH levels, while astrocytes respond by increasing cellular NADH/NAD{sup +} ratio.
Date: August 18, 2008
Creator: Xi, Wenjun
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Effects of Substrate and Co-Culture on Neural Progenitor Cell Differentiation (open access)

Effects of Substrate and Co-Culture on Neural Progenitor Cell Differentiation

In recent years the study of stem and progenitor cells has moved to the forefront of research. Since the isolation of human hematopoietic stem cells in 1988 and the subsequent discovery of a self renewing population of multipotent cells in many tissues, many researchers have envisioned a better understanding of development and potential clinical usage in intractable diseases. Both these goals, however, depend on a solid understanding of the intracellular and extracellular forces that cause stem cells to differentiate to a specific cell fate. Many diseases of large scale cell loss have been suggested as candidates for stem cell based treatments. It is proposed that replacing the function of the damaged or defective cells by specific differentiation of stem or progenitor cells could treat the disease. Before cells can be directed to specific lineages, the mechanisms of differentiation must be better understood. Differentiation in vivo is an intensively complex system that is difficult to study. The goal of this research is to develop further understanding of the effects of soluble and extracellular matrix (ECM) cues on the differentiation of neural progenitor cells with the use of a simplified in vitro culture system. Specific research objectives are to study the differentiation …
Date: August 18, 2008
Creator: Jones, Erin Boote
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Evidence of half-metallic interface magnetism via local moment formation in Co based Heusler alloys (open access)

Evidence of half-metallic interface magnetism via local moment formation in Co based Heusler alloys

In this work we use a combination of x-ray magnetic circular and linear dichroism (XMCD and XMLD) techniques to examine the formation of local moments in Heusler alloys of the composition Co{sub 2}MnX (where X=Si or Al). The existence of local moments in a half-metallic system is reliant upon the band gap in the minority-spin states. By utilizing the element-specific nature of x-ray techniques we are able to explore the origin of the minority-spin band gap in the partial density of states (PDOS), via the degree of localization of moments on Co and Mn atoms. We observe a crucial difference in the localization of the Co moment when comparing Co{sub 2}MnSi (CMS) and Co{sub 2}MnAl (CMA) films that is consistent with the predicted larger minority-spin gap in the Co PDOS for CMS. These results provide important evidence for the dominant role of the Co minority-spin states in realizing half-metallic ferromagnetism (HMF) in these Heusler alloys. They also demonstrate a direct method for measuring the degree of interfacial HMF in the raw materials without the need for fabricating spin-transport devices.
Date: August 18, 2008
Creator: Telling, N. D.; Keatley, P. S.; van der Laan, G.; Hicken, R. J.; Arenholz, E.; Sakuraba, Y. et al.
Object Type: Article
System: The UNT Digital Library
Evolution, Interaction, and Intrinsic Properties of Dislocations in Intermetallics: Anisotropic 3D Dislocation Dynamics Approach (open access)

Evolution, Interaction, and Intrinsic Properties of Dislocations in Intermetallics: Anisotropic 3D Dislocation Dynamics Approach

The generation, motion, and interaction of dislocations play key roles during the plastic deformation process of crystalline solids. 3D Dislocation Dynamics has been employed as a mesoscale simulation algorithm to investigate the collective and cooperative behavior of dislocations. Most current research on 3D Dislocation Dynamics is based on the solutions available in the framework of classical isotropic elasticity. However, due to some degree of elastic anisotropy in almost all crystalline solids, it is very necessary to extend 3D Dislocation Dynamics into anisotropic elasticity. In this study, first, the details of efficient and accurate incorporation of the fully anisotropic elasticity into 3D discrete Dislocation Dynamics by numerically evaluating the derivatives of Green's functions are described. Then the intrinsic properties of perfect dislocations, including their stability, their core properties and disassociation characteristics, in newly discovered rare earth-based intermetallics and in conventional intermetallics are investigated, within the framework of fully anisotropic elasticity supplemented with the atomistic information obtained from the ab initio calculations. Moreover, the evolution and interaction of dislocations in these intermetallics as well as the role of solute segregation are presented by utilizing fully anisotropic 3D dislocation dynamics. The results from this work clearly indicate the role and the importance of …
Date: August 18, 2008
Creator: Chen, Qian
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Final Report: DOE/ID/14215 (open access)

Final Report: DOE/ID/14215

The proposed straw separation system developed in the research project harvests the large internode sections of the straw which has the greater potential as a feedstock for lignocellulosic ethanol production while leaving the chaff and nodes in the field. This strategy ensures sustainable agriculture by preventing the depletion of soil minerals, and it restores organic matter to the soil in amounts and particle sizes that accommodate farmers’ needs to keep tillage and fertilizer costs low. A ton of these nutrient-rich plant tissues contains as much as $10.55 worth of fertilizer (economic and energy benefits), in terms of nitrogen, phosphorus, potassium, and other nutrients provided to the soil when incorporated by tillage instead of being burned. Biomass conversion to fermentable sugars for the purpose of producing fuels, chemicals, and other industrial products is well understood. Most bioenergy strategies rely on low-cost fermentable sugars for sustainability and economic viability in the marketplace. Exploitation of the “whole crop”—specifically, wheat straw or other plant material currently regarded as residue or waste—is a practical approach for obtaining a reliable and low-cost source of sugars. However, industrial-scale production of sugars from wheat straw, while technically feasible, is plagued by obstacles related to capital costs, energy consumption, …
Date: August 18, 2008
Creator: Bryden, Kenneth; Hess, J. Richard; Ulrich, Thomas & Zemetra, Robert
Object Type: Report
System: The UNT Digital Library
Indian Tribal Civil Jurisdiction’s Reach Over Non-Indians: Plains Commerce Bank v. Long Family Land and Cattle Co., Inc. (open access)

Indian Tribal Civil Jurisdiction’s Reach Over Non-Indians: Plains Commerce Bank v. Long Family Land and Cattle Co., Inc.

None
Date: August 18, 2008
Creator: Kim, Yule
Object Type: Report
System: The UNT Digital Library
Inductively Coupled Plasma: Fundamental Particle Investigations with Laser Ablation and Applications in Magnetic Sector Mass Spectrometry (open access)

Inductively Coupled Plasma: Fundamental Particle Investigations with Laser Ablation and Applications in Magnetic Sector Mass Spectrometry

Particle size effects and elemental fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are investigated with nanosecond and femtosecond laser ablation, differential mobility analysis, and magnetic sector ICP-MS. Laser pulse width was found to have a significant influence on the LA particle size distribution and the elemental composition of the aerosol and thus fractionation. Emission from individual particles from solution nebulization, glass, and a pressed powder pellet are observed with high speed digital photography. The presence of intact particles in an ICP is shown to be a likely source of fractionation. A technique for the online detection of stimulated elemental release from neural tissue using magnetic sector ICP-MS is described. Detection limits of 1 {micro}g L{sup -1} or better were found for P, Mn, Fe, Cu, and Zn in a 60 {micro}L injection in a physiological saline matrix.
Date: August 18, 2008
Creator: Saetveit, Nathan Joe
Object Type: Thesis or Dissertation
System: The UNT Digital Library
An Investigation Into Bayesian Networks for Modeling National Ignition Facility Capsule Implosions (open access)

An Investigation Into Bayesian Networks for Modeling National Ignition Facility Capsule Implosions

Bayesian networks (BN) are an excellent tool for modeling uncertainties in systems with several interdependent variables. A BN is a directed acyclic graph, and consists of a structure, or the set of directional links between variables that depend on other variables, and conditional probabilities (CP) for each variable. In this project, we apply BN's to understand uncertainties in NIF ignition experiments. One can represent various physical properties of National Ignition Facility (NIF) capsule implosions as variables in a BN. A dataset containing simulations of NIF capsule implosions was provided. The dataset was generated from a radiation hydrodynamics code, and it contained 120 simulations of 16 variables. Relevant knowledge about the physics of NIF capsule implosions and greedy search algorithms were used to search for hypothetical structures for a BN. Our preliminary results found 6 links between variables in the dataset. However, we thought there should have been more links between the dataset variables based on the physics of NIF capsule implosions. Important reasons for the paucity of links are the relatively small size of the dataset, and the sampling of the values for dataset variables. Another factor that might have caused the paucity of links is the fact that in …
Date: August 18, 2008
Creator: Mitrani, J.
Object Type: Report
System: The UNT Digital Library
Investigations of the R5(SixGe1-x)4 Intermetallic Compounds by X-Ray Resonant Magnetic Scattering (open access)

Investigations of the R5(SixGe1-x)4 Intermetallic Compounds by X-Ray Resonant Magnetic Scattering

The XRMS experiment on the Gd{sub 5}Ge{sub 4} system has shown that, below the Neel temperature, T{sub N} = 127 K, the magnetic unit cells is the same as the chemical unit cell. From azimuth scans and the Q dependence of the magnetic scattering, all three Gd sites in the structure were determined to be in the same magnetic space group Pnma. The magnetic moments are aligned along the c-axis and the c-components of the magnetic moments at the three different sites are equal. The ferromagnetic slabs are stacked antiferromagnetically along the b-direction. They found an unusual order parameter curve in Gd{sub 5}Ge{sub 4}. A spin-reorientation transition is a possibility in Gd{sub 5}Ge{sub 4}, which is similar to the Tb{sub 5}Ge{sub 4} case. Tb{sub 5}Ge{sub 4} possesses the same Sm{sub 5}Ge{sub 4}-type crystallographic structure and the same magnetic space group as Gd{sub 5}Ge{sub 4} does. The difference in magnetic structure is that Tb{sub 5}Ge{sub 4} has a canted one but Gd{sub 5}Ge{sub 4} has nearly a collinear one in the low temperature antiferromagnetic phase. The competition between the magneto-crystalline anisotropy and the nearest-neighbor magnetic exchange interactions may allow a 3-dimensional canted antiferromagnetic structure in Tb{sub 5}Ge{sub 4}. The spin-reorientation transition …
Date: August 18, 2008
Creator: Tan, Lizhi
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Investment and Upgrade in Distributed Generation under Uncertainty (open access)

Investment and Upgrade in Distributed Generation under Uncertainty

The ongoing deregulation of electricity industries worldwide is providing incentives for microgrids to use small-scale distributed generation (DG) and combined heat and power (CHP) applications via heat exchangers (HXs) to meet local energy loads. Although the electric-only efficiency of DG is lower than that of central-station production, relatively high tariff rates and the potential for CHP applications increase the attraction of on-site generation. Nevertheless, a microgrid contemplatingthe installation of gas-fired DG has to be aware of the uncertainty in the natural gas price. Treatment of uncertainty via real options increases the value of the investment opportunity, which then delays the adoption decision as the opportunity cost of exercising the investment option increases as well. In this paper, we take the perspective of a microgrid that can proceed in a sequential manner with DG capacity and HX investment in order to reduce its exposure to risk from natural gas price volatility. In particular, with the availability of the HX, the microgrid faces a tradeoff between reducing its exposure to the natural gas price and maximising its cost savings. By varying the volatility parameter, we find that the microgrid prefers a direct investment strategy for low levels of volatility and a sequential …
Date: August 18, 2008
Creator: Siddiqui, Afzal & Maribu, Karl
Object Type: Article
System: The UNT Digital Library
Measurement of Branching Fractions of Radiative Charm Decays (open access)

Measurement of Branching Fractions of Radiative Charm Decays

We present a measurement of the branching fractions for the Cabibbo-favored radiative decay, D{sup 0} {yields} {bar K}*{sup 0}{gamma}, and the Cabibbo-suppressed radiative decay, D{sup 0} {yields} {phi}{gamma}. These measurements are based on a data sample corresponding to an integrated luminosity of 387.1 fb{sup -1}, recorded with the BABAR detector at the PEP-II e{sup +}e{sup -} asymmetric-energy collider operating at center-of-mass energies 10.58 and 10.54 GeV. We measure the branching fractions relative to the well-studied decay D{sup 0} {yields} K{sup -}{pi}{sup +} and find {Beta}(D{sup 0} {yields} {bar K}*{sup 0}{gamma})/{Beta}(D{sup 0} {yields} K{sup -}{pi}{sup +}) = (8.43 {+-} 0.51 {+-} 0.70) x 10{sup -3} and {Beta}(D{sup 0} {yields} {phi}{gamma})/{Beta}(D{sup 0} {yields} K{sup -}{pi}{sup +}) = (7.15 {+-} 0.78 {+-} 0.69) x 10{sup -4}, where the first error is statistical and the second is systematic. This is the first measurement of {Beta}(D{sup 0} {yields} {bar K}*{sup 0} {gamma}).
Date: August 18, 2008
Creator: Aubert, B.
Object Type: Article
System: The UNT Digital Library
Midwest Floods of 2008: Potential Impact on Agriculture (open access)

Midwest Floods of 2008: Potential Impact on Agriculture

This report discusses the potential impact on agriculture of June flooding across much of the Corn Belt. As much as 5 million acres of crop production were initially thought to be either lost entirely or subject to significant yield reductions.
Date: August 18, 2008
Creator: Schnepf, Randy
Object Type: Report
System: The UNT Digital Library
Novel Bioplastics and biocomposites from Vegetable Oils (open access)

Novel Bioplastics and biocomposites from Vegetable Oils

Polymeric materials have been prevalent in our everyday lives for quite a long time. Most of today's polymeric materials are derived from nonrenewable petroleum-based feedstocks. Instabilities in the regions where petroleum is drilled, along with an increased demand in petroleum, have driven the price of crude oil to record high prices. This, in effect, increases the price of petroleum-based polymeric materials, which has caused a heightened awareness of renewable alternatives for polymeric feedstocks. Cellulose, starch, proteins and natural oils have all been examined as possible polymeric feedstocks. Natural oils are commercially available on a large scale and are relatively cheap. It is projected that the U.S. alone will produce 21 billion pounds of soybean oil in the period 2008/2009. Natural oils also have the advantages of inherent biodegradability, low toxicity, high purity and ready availability. Most natural oils possess a triglyceride structure as shown in Figure 1. Most natural oils have a unique distribution of fatty acid side chains, along with varying degrees of unsaturation per triglyceride. Common fatty acid side chains in naturally occurring oils are palmitic acid (C16:0), a 16 carbon fatty acid with no unsaturation; stearic acid (C18:0), an 18 carbon fatty acid with no unsaturation; oleic …
Date: August 18, 2008
Creator: Henna, Phillip H.
Object Type: Thesis or Dissertation
System: The UNT Digital Library