Dynamic Behavior of Sand: Annual Report FY 11 (open access)

Dynamic Behavior of Sand: Annual Report FY 11

Currently, design of earth-penetrating munitions relies heavily on empirical relationships to estimate behavior, making it difficult to design novel munitions or address novel target situations without expensive and time-consuming full-scale testing with relevant system and target characteristics. Enhancing design through numerical studies and modeling could help reduce the extent and duration of full-scale testing if the models have enough fidelity to capture all of the relevant parameters. This can be separated into three distinct problems: that of the penetrator structural and component response, that of the target response, and that of the coupling between the two. This project focuses on enhancing understanding of the target response, specifically granular geomaterials, where the temporal and spatial multi-scale nature of the material controls its response. As part of the overarching goal of developing computational capabilities to predict the performance of conventional earth-penetrating weapons, this project focuses specifically on developing new models and numerical capabilities for modeling sand response in ALE3D. There is general recognition that granular materials behave in a manner that defies conventional continuum approaches which rely on response locality and which degrade in the presence of strong response nonlinearities, localization, and phase gradients. There are many numerical tools available to address …
Date: March 15, 2012
Creator: Antoun, Tarabay; Herbold, Eric & Johnson, Scott
Object Type: Report
System: The UNT Digital Library
Evaluating greenhouse gas emissions from hydropower complexes on large rivers in Eastern Washington (open access)

Evaluating greenhouse gas emissions from hydropower complexes on large rivers in Eastern Washington

Water bodies, such as freshwater lakes, are known to be net emitters of carbon dioxide (CO2), and methane (CH4). In recent years, significant greenhouse gas (GHG) emissions from tropical, boreal, and mid-latitude reservoirs have been reported. At a time when hydropower is increasing worldwide, better understanding of seasonal and regional variation in GHG emissions is needed in order to develop a predictive understanding of such fluxes within man-made impoundments. We examined power-producing dam complexes within xeric temperate locations in the northwestern United States. Sampling environments on the Snake (Lower Monumental Dam Complex) and Columbia Rivers (Priest Rapids Dam Complex) included tributary, mainstem, embayment, forebay, and tailrace areas during winter and summer 2012. At each sampling location, GHG measurement pathways included surface gas flux, degassing as water passed through dams during power generation, ebullition within littoral embayments, and direct sampling of hyporheic pore-water. Measurements were also carried out in a free-flowing reach of the Columbia River to estimate unaltered conditions. Surface flux resulted in very low emissions, with reservoirs acting as a sink for CO2 (up to –262 mg m-2 d-1, which is within the range previously reported for similarly located reservoirs). Surface flux of methane remained below 1 mg CH4 …
Date: March 15, 2013
Creator: Arntzen, Evan V.; Miller, Benjamin L.; O'Toole, Amanda C.; Niehus, Sara E. & Richmond, Marshall C.
Object Type: Report
System: The UNT Digital Library
TANK 40 FINAL SB7B CHEMICAL CHARACTERIZATION RESULTS (open access)

TANK 40 FINAL SB7B CHEMICAL CHARACTERIZATION RESULTS

A sample of Sludge Batch 7b (SB7b) was taken from Tank 40 in order to obtain radionuclide inventory analyses necessary for compliance with the Waste Acceptance Product Specifications (WAPS). The SB7b WAPS sample was also analyzed for chemical composition including noble metals and fissile constituents, and these results are reported here. These analyses along with the WAPS radionuclide analyses will help define the composition of the sludge in Tank 40 that is currently being fed to the Defense Waste Processing Facility (DWPF) as SB7b. At the Savannah River National Laboratory (SRNL) the 3-L Tank 40 SB7b sample was transferred from the shipping container into a 4-L high density polyethylene bottle and solids were allowed to settle over the weekend. Supernate was then siphoned off and circulated through the shipping container to complete the transfer of the sample. Following thorough mixing of the 3-L sample, a 558 g sub-sample was removed. This sub-sample was then utilized for all subsequent analytical samples. Eight separate aliquots of the slurry were digested, four with HNO{sub 3}/HCl (aqua regia) in sealed Teflon{reg_sign} vessels and four with NaOH/Na{sub 2}O{sub 2} (alkali or peroxide fusion) using Zr crucibles. Two Analytical Reference Glass - 1 (ARG-1) standards were …
Date: March 15, 2012
Creator: Bannochie, C.
Object Type: Report
System: The UNT Digital Library
Limit of detection of Bacillus anthracis in complex soil and air samples using next-generation sequencing (open access)

Limit of detection of Bacillus anthracis in complex soil and air samples using next-generation sequencing

None
Date: March 15, 2012
Creator: Be, Nicholas A.; Thissen, James B.; Gardner, Shea; McLoughlin, Kevin; Fofanov, Viacheslav; Koshinsky, Heather et al.
Object Type: Article
System: The UNT Digital Library
Measurement of the D_s Decay Constant f_Ds and Observation of New Charm Resonances Decaying to D^(*)\pi (open access)

Measurement of the D_s Decay Constant f_Ds and Observation of New Charm Resonances Decaying to D^(*)\pi

The absolute branching fractions for the decays D{sub s}{sup -} {yields} {ell}{sup -}{bar {nu}}{sub {ell}} ({ell} = e, {mu}, or {tau}) are measured using a data sample corresponding to an integrated luminosity of 521 fb{sup -1} collected at center of mass energies near 10.58 GeV with the BABAR detector at the PEPII e{sup +}e{sup -} collider at SLAC. The number of D{sub s}{sup -} mesons is determined by reconstructing the recoiling system DKX{gamma} in events of the type e{sup +}e{sup -} {yields} DKXD*{sub s}{sup -}, where D*{sub s}{sup -} {yields} D{sub s}{sup -} {gamma} and X represents additional pions from fragmentation. The D{sub s}{sup -} {yields} {ell}{sup -}{nu}{sub {ell}} events are detected by full or partial reconstruction of the recoiling system DKX{gamma}{ell}. The following results are obtained: {Beta}(D{sub s}{sup -} {yields} {mu}{sup -}{nu}) = (6.02 {+-} 0.38 {+-} 0.34) x 10{sup -3}, {Beta}(D{sub s}{sup -} {yields} {tau}{sup -}{nu}) = (5.00 {+-} 0.35 {+-} 0.49) x 10{sup -2}, and B(D{sub s}{sup -} {yields} e{sup -}{nu}) < 2.8 x 10{sup -4} at 90% C.L., where the first uncertainty is statistical and the second is systematic. The branching fraction measurements are combined to determine the D{sub s}{sup -} decay constant f{sub D{sub s}} …
Date: March 15, 2012
Creator: Benitez, Jose
Object Type: Thesis or Dissertation
System: The UNT Digital Library
OpenMP for Accelerators (open access)

OpenMP for Accelerators

OpenMP [13] is the dominant programming model for shared-memory parallelism in C, C++ and Fortran due to its easy-to-use directive-based style, portability and broad support by compiler vendors. Similar characteristics are needed for a programming model for devices such as GPUs and DSPs that are gaining popularity to accelerate compute-intensive application regions. This paper presents extensions to OpenMP that provide that programming model. Our results demonstrate that a high-level programming model can provide accelerated performance comparable to hand-coded implementations in CUDA.
Date: March 15, 2011
Creator: Beyer, J C; Stotzer, E J; Hart, A & de Supinski, B R
Object Type: Article
System: The UNT Digital Library
The Endangered Species Act (ESA) in the 112th Congress: Conflicting Values and Difficult Choices (open access)

The Endangered Species Act (ESA) in the 112th Congress: Conflicting Values and Difficult Choices

None
Date: March 15, 2012
Creator: Buck, Eugene H.; Corn, M. Lynne; Alexander, Kristina; Sheikh, Pervaze A. & Meltz, Robert
Object Type: Report
System: The UNT Digital Library
Fukushima Nuclear Crisis (open access)

Fukushima Nuclear Crisis

This report briefly discusses the March 11, 2001, earthquake off the east coast of Honshu, Japan's largest island. The earthquake caused an automatic shutdown of eleven of Japan's fifty-five operating nuclear power plants. The plants closes to the earthquake's epicenter, Fukushima and Onagawa, were damaged by the earthquake and resulting tsunami. This report also discusses efforts by the United States and other countries to provide assistance to Japan to deal with the nuclear crisis.
Date: March 15, 2011
Creator: Campbell, Richard J.
Object Type: Report
System: The UNT Digital Library
Final Report for DOE Project Number: DE-FG02-05ER46241 (open access)

Final Report for DOE Project Number: DE-FG02-05ER46241

Hydrogen storage is the most challenging task for the hydrogen economy. We established a multidisciplinary research program for high throughput combinatorial synthesis and characterization of novel nanoporous and metastable complex hydrides, coupled to fundamental material studies including electronic, structural and kinetic transport modeling, and pump-probe experiments. Our research is based the concept of hybrid nanostructures that store hydrogen by a combination of chemi- and physorption: atomic hydrogen is stored in metastable hydrides while molecule hydrogen is stored in the nanometer pores of the hydrides. Metastable nanostructured hydride has been achieved by introducing structural and compositional disorders through high throughput elemental substitution/doping, catalyst addition, and nonequilibrium processing. Fast screening compatible with the combinatorial synthesis was achieved by combining X-ray structural characterization with the development of a laser-based microbalance. Manufacturing of nanoporous metahydrides that are identified as promising by the combinatorial synthesis has been explored along with the materials search.
Date: March 15, 2010
Creator: Chen, Gang; Dresselhaus, Mildred S.; Grigoropoulos, Costas P.; Mao, Samuel S.; Xiang, Xiaodong & Zeng, Taofang
Object Type: Report
System: The UNT Digital Library
Surrogate-based optimization of hydraulic fracturing in pre-existing fracture networks (open access)

Surrogate-based optimization of hydraulic fracturing in pre-existing fracture networks

None
Date: March 15, 2013
Creator: Chen, M; Sun, Y; Fu, P; Carrigan, C R; Lu, Z & Tong, C H
Object Type: Article
System: The UNT Digital Library
Methods for Engineering Sulfate Reducing Bacteria of the Genus Desulfovibrio (open access)

Methods for Engineering Sulfate Reducing Bacteria of the Genus Desulfovibrio

Sulfate reducing bacteria are physiologically important given their nearly ubiquitous presence and have important applications in the areas of bioremediation and bioenergy. This chapter provides details on the steps used for homologous-recombination mediated chromosomal manipulation of Desulfovibrio vulgaris Hildenborough, a well-studied sulfate reducer. More specifically, we focus on the implementation of a 'parts' based approach for suicide vector assembly, important aspects of anaerobic culturing, choices for antibiotic selection, electroporation-based DNA transformation, as well as tools for screening and verifying genetically modified constructs. These methods, which in principle may be extended to other sulfate-reducing bacteria, are applicable for functional genomics investigations, as well as metabolic engineering manipulations.
Date: March 15, 2011
Creator: Chhabra, Swapnil R; Keller, Kimberly L. & Wall, Judy D.
Object Type: Book
System: The UNT Digital Library
Real-time manifestation of strongly coupled spin and charge order parameters in stripe-ordered nickelates via time-resolved resonant x-ray diffraction (open access)

Real-time manifestation of strongly coupled spin and charge order parameters in stripe-ordered nickelates via time-resolved resonant x-ray diffraction

None
Date: March 15, 2013
Creator: Chuang, Y. D.; Lee, W. S.; Kung, Y. F.; Sorini, A. P.; Moritz, B.; Moore, R. G. et al.
Object Type: Article
System: The UNT Digital Library
Three-dimensional induced polarization data inversion for complex resistivity (open access)

Three-dimensional induced polarization data inversion for complex resistivity

The conductive and capacitive material properties of the subsurface can be quantified through the frequency-dependent complex resistivity. However, the routine three-dimensional (3D) interpretation of voluminous induced polarization (IP) data sets still poses a challenge due to large computational demands and solution nonuniqueness. We have developed a flexible methodology for 3D (spectral) IP data inversion. Our inversion algorithm is adapted from a frequency-domain electromagnetic (EM) inversion method primarily developed for large-scale hydrocarbon and geothermal energy exploration purposes. The method has proven to be efficient by implementing the nonlinear conjugate gradient method with hierarchical parallelism and by using an optimal finite-difference forward modeling mesh design scheme. The method allows for a large range of survey scales, providing a tool for both exploration and environmental applications. We experimented with an image focusing technique to improve the poor depth resolution of surface data sets with small survey spreads. The algorithm's underlying forward modeling operator properly accounts for EM coupling effects; thus, traditionally used EM coupling correction procedures are not needed. The methodology was applied to both synthetic and field data. We tested the benefit of directly inverting EM coupling contaminated data using a synthetic large-scale exploration data set. Afterward, we further tested the monitoring …
Date: March 15, 2011
Creator: Commer, M.; Newman, G. A.; Williams, K. H. & Hubbard, S. S.
Object Type: Article
System: The UNT Digital Library
Extension of the weak-line approximation and application to correlated-k methods (open access)

Extension of the weak-line approximation and application to correlated-k methods

Global climate models require accurate and rapid computation of the radiative transfer through the atmosphere. Correlated-k methods are often used. One of the approximations used in correlated-k models is the weakline approximation. We introduce an approximation T/sub g/ which reduces to the weak-line limit when optical depths are small, and captures the deviation from the weak-line limit as the extinction deviates from the weak-line limit. This approximation is constructed to match the first two moments of the gamma distribution to the k-distribution of the transmission. We compare the errors of the weak-line approximation with T/sub g/ in the context of a water vapor spectrum. The extension T/sub g/ is more accurate and converges more rapidly than the weak-line approximation.
Date: March 15, 2011
Creator: Conley, A.J. & Collins, W.D.
Object Type: Article
System: The UNT Digital Library
Côte d'Ivoire's Post-Election Crisis (open access)

Côte d'Ivoire's Post-Election Crisis

This report discusses the contested November 28, 2010, presidential election runoff election in Côte d'Ivoire. Laurent Gbagbo and his rival, former Prime Minister Alassane Ouattara, both continue to claim to have won the runoff and to exercise exclusive national executive authority, and to attempt to consolidate their control over state institutions. An increase in armed conflicts in late February 2011, among other indicators, signals the possible outbreak of a renewed civil war. This report discusses these events, as well as U.S. and international efforts to support a peaceful transition in Côte d'Ivoire, which has remained largely divided since the civil war that began in 2002.
Date: March 15, 2011
Creator: Cook, Nicolas
Object Type: Report
System: The UNT Digital Library
Constraints on the pMSSM from LAT Observations of Dwarf Spheroidal Galaxies (open access)

Constraints on the pMSSM from LAT Observations of Dwarf Spheroidal Galaxies

We examine the ability for the Large Area Telescope (LAT) to constrain Minimal Supersymmetric Standard Model (MSSM) dark matter through a combined analysis of Milky Way dwarf spheroidal galaxies. We examine the Lightest Supersymmetric Particles (LSPs) for a set of {approx}71k experimentally valid supersymmetric models derived from the phenomenological-MSSM (pMSSM). We find that none of these models can be excluded at 95% confidence by the current analysis; nevertheless, many lie within the predicted reach of future LAT analyses. With two years of data, we find that the LAT is currently most sensitive to light LSPs (mLSP < 50 GeV) annihilating into {tau}-pairs and heavier LSPs annihilating into b{bar b}. Additionally, we find that future LAT analyses will be able to probe some LSPs that form a sub-dominant component of dark matter. We directly compare the LAT results to direct detection experiments and show the complementarity of these search methods.
Date: March 15, 2012
Creator: Cotta, R. C.; Drlica-Wagner, A.; Murgia, S.; Bloom, E. D.; Hewett, J. L. & Rizzo, T. G.
Object Type: Article
System: The UNT Digital Library
Africa: U.S. Foreign Assistance Issues (open access)

Africa: U.S. Foreign Assistance Issues

The United States provides assistance to 47 African countries, and the United States Agency for International Development (USAID) has 23 missions in Africa. In recent years, U.S. assistance to Africa saw a major increase, especially in health-related programs. This report provides an overview of U.S. aid to Africa, including the strategic objectives that shape U.S. aid to Africa, information about specific aid programs and initiatives, and the Obama Administration's FY2011 foreign aid budget request.
Date: March 15, 2011
Creator: Dagne, Ted
Object Type: Report
System: The UNT Digital Library
Uganda: Current Conditions and the Crisis in North Uganda (open access)

Uganda: Current Conditions and the Crisis in North Uganda

This report discusses the current political conditions of Uganda, which has long been ravaged by the Lord's Resistance Army (LRA), an armed rebel group backed by the government of Sudan. In particular, the report focuses on largely-unsuccessful Ugandan efforts to resolve the conflict with the LRA, as well as talks with the U.S. under the Bush Administration and the recent suicide bombings in Kampala, Uganda, in July 2010.
Date: March 15, 2011
Creator: Dagne, Ted
Object Type: Report
System: The UNT Digital Library
The Amending Process in the Senate (open access)

The Amending Process in the Senate

This report is intended to provide an overview of the fundamentals of the Senate amendment process. It summarizes many of the rules, precedents, and practices of the Senate affecting the consideration of amendments to measures on the floor.
Date: March 15, 2013
Creator: Davis, Christopher M.
Object Type: Report
System: The UNT Digital Library
Commonly Used Motions and Requests in the House of Representatives (open access)

Commonly Used Motions and Requests in the House of Representatives

This report identifies the most commonly used motions and requests available to Members during proceedings in the House of Representatives. It does not identify motions and requests used when the House is in the Committee of the Whole House on the State of the Union.
Date: March 15, 2013
Creator: Davis, Christopher M.
Object Type: Report
System: The UNT Digital Library
Secret Sessions of the House and Senate: Authority, Confidentiality, and Frequency (open access)

Secret Sessions of the House and Senate: Authority, Confidentiality, and Frequency

This report discusses secret, or closed, sessions of the House and Senate exclude the press and the public.
Date: March 15, 2013
Creator: Davis, Christopher M.
Object Type: Report
System: The UNT Digital Library
Testing the OPERA Superluminal Neutrino Anomaly at the LHC (open access)

Testing the OPERA Superluminal Neutrino Anomaly at the LHC

The OPERA collaboration has reported the observation of superluminal muon neutrinos, whose speed v{sub {nu}} exceeds that of light c, with (v{sub {nu}}-c)/c {approx_equal} 2.5 x 10{sup -5}. In a recent work, Cohen and Glashow (CG) have refuted this claim by noting that such neutrinos will lose energy, by pair-emission of particles, at unacceptable rates. Following the CG arguments, we point out that pair-emissions consistent with the OPERA anomaly can lead to detectable signals for neutrinos originating from decays of highly boosted top quarks at the LHC, allowing an independent test of the superluminal neutrino hypothesis.
Date: March 15, 2012
Creator: Davoudiasl, Hooman; /Brookhaven & Rizzo, Thomas G.
Object Type: Article
System: The UNT Digital Library
City of Denton debt summary report as of September 30, 2018 (open access)

City of Denton debt summary report as of September 30, 2018

This report describes the City two types of long-term debt: General Obligation Debt and Revenue Bond Debt. The City also differentiates between tax-supported and revenue-supported debt to provide the public with a clear understanding of what debt will be paid by property taxes versus rate revenues. However, Data provided in this report is as of the date of publication and constitutes existing long-term debt obligations only. This report does not include forward looking statements nor does it include debt that may be incurred in the future. Interested parties should refer to the City’s audited financial statements and other disclosure documents when investing.
Date: March 15, 2019
Creator: Denton. Finance Department
Object Type: Report
System: The Portal to Texas History
Japan 2011 Disaster: CRS Experts (open access)

Japan 2011 Disaster: CRS Experts

The following table provides access to names and contact information for CRS experts on policy concerns relating to the nuclear and humanitarian disaster unfolding in Japan. Specific policy areas are identified.
Date: March 15, 2011
Creator: Dolven, Ben
Object Type: Report
System: The UNT Digital Library