Resource Type

150 Matching Results

Results open in a new window/tab.

Military and Security Developments Involving the Democratic People's Republic of Korea (open access)

Military and Security Developments Involving the Democratic People's Republic of Korea

A report that discusses the security threat of North Korea with particular focus on nuclear weapons and technology.
Date: February 15, 2013
Creator: United States. Office of the Secretary of Defense.
System: The UNT Digital Library
High Efficiency Integrated Package (open access)

High Efficiency Integrated Package

Solid-state lighting based on LEDs has emerged as a superior alternative to inefficient conventional lighting, particularly incandescent. LED lighting can lead to 80 percent energy savings; can last 50,000 hours – 2-50 times longer than most bulbs; and contains no toxic lead or mercury. However, to enable mass adoption, particularly at the consumer level, the cost of LED luminaires must be reduced by an order of magnitude while achieving superior efficiency, light quality and lifetime. To become viable, energy-efficient replacement solutions must deliver system efficacies of ≥ 100 lumens per watt (LPW) with excellent color rendering (CRI > 85) at a cost that enables payback cycles of two years or less for commercial applications. This development will enable significant site energy savings as it targets commercial and retail lighting applications that are most sensitive to the lifetime operating costs with their extended operating hours per day. If costs are reduced substantially, dramatic energy savings can be realized by replacing incandescent lighting in the residential market as well. In light of these challenges, Cree proposed to develop a multi-chip integrated LED package with an output of > 1000 lumens of warm white light operating at an efficacy of at least 128 …
Date: September 15, 2013
Creator: Ibbetson, James
System: The UNT Digital Library
Final Report: Large-Scale Optimization for Bayesian Inference in Complex Systems (open access)

Final Report: Large-Scale Optimization for Bayesian Inference in Complex Systems

The SAGUARO (Scalable Algorithms for Groundwater Uncertainty Analysis and Robust Optimiza- tion) Project focuses on the development of scalable numerical algorithms for large-scale Bayesian inversion in complex systems that capitalize on advances in large-scale simulation-based optimiza- tion and inversion methods. Our research is directed in three complementary areas: efficient approximations of the Hessian operator, reductions in complexity of forward simulations via stochastic spectral approximations and model reduction, and employing large-scale optimization concepts to accelerate sampling. Our efforts are integrated in the context of a challenging testbed problem that considers subsurface reacting flow and transport. The MIT component of the SAGUARO Project addresses the intractability of conventional sampling methods for large-scale statistical inverse problems by devising reduced-order models that are faithful to the full-order model over a wide range of parameter values; sampling then employs the reduced model rather than the full model, resulting in very large computational savings. Results indicate little effect on the computed posterior distribution. On the other hand, in the Texas-Georgia Tech component of the project, we retain the full-order model, but exploit inverse problem structure (adjoint-based gradients and partial Hessian information of the parameter-to- observation map) to implicitly extract lower dimensional information on the posterior distribution; …
Date: October 15, 2013
Creator: Ghattas, Omar
System: The UNT Digital Library
Future Automotive Aftertreatment Solutions: The 150°C Challenge Workshop Report (open access)

Future Automotive Aftertreatment Solutions: The 150°C Challenge Workshop Report

With future fuel economy standards enacted, the U.S. automotive manufacturers (OEMs) are committed to pursuing a variety of high risk/highly efficient stoichiometric and lean combustion strategies to achieve superior performance. In recognition of this need, the U.S. Department of Energy (DOE) has partnered with domestic automotive manufacturers through U.S. DRIVE to develop these advanced technologies. However, before these advancements can be introduced into the U.S. market, they must also be able to meet increasingly stringent emissions requirements. A significant roadblock to this implementation is the inability of current catalyst and aftertreatment technologies to provide the required activity at the much lower exhaust temperatures that will accompany highly efficient combustion processes and powertrain strategies. Therefore, the goal of this workshop and report is to create a U.S. DRIVE emission control roadmap that will identify new materials and aftertreatment approaches that offer the potential for 90% conversion of emissions at low temperature (150°C) and are consistent with highly efficient combustion technologies currently under investigation within U.S. DRIVE Advanced Combustion and Emission Control (ACEC) programs.
Date: October 15, 2013
Creator: Zammit, Michael; DiMaggio, Craig L.; Kim, Chang H.; Lambert, Christine; Muntean, George G.; Peden, Charles HF et al.
System: The UNT Digital Library
THERMAL PERFORMANCE SENSITIVITY STUDIES IN SUPPORT OF MATERIAL MODELING FOR EXTENDED STORAGE OF USED NUCLEAR FUEL (open access)

THERMAL PERFORMANCE SENSITIVITY STUDIES IN SUPPORT OF MATERIAL MODELING FOR EXTENDED STORAGE OF USED NUCLEAR FUEL

The work reported here is an investigation of the sensitivity of component temperatures of a storage system, including fuel cladding temperatures, in response to age-related changes that could degrade the design-basis thermal behavior of the system. Three specific areas of interest were identified for this study. • degradation of the canister backfill gas from pure helium to a mixture of air and helium, resulting from postulated leakage due to stress corrosion cracking (SCC) of canister welds • changes in surface emissivity of system components, resulting from corrosion or other aging mechanisms, which could cause potentially significant changes in temperatures and temperature distributions, due to the effect on thermal radiation exchange between components • changes in fuel and basket temperatures due to changes in fuel assembly position within the basket cells in the canister The purpose of these sensitivity studies is to provide a realistic example of how changes in the physical properties or configuration of the storage system components can affect temperatures and temperature distributions. The magnitudes of these sensitivities can provide guidance for identifying appropriate modeling assumptions for thermal evaluations extending long term storage out beyond 50, 100, 200, and 300 years.
Date: August 15, 2013
Creator: Cuta, Judith M.; Suffield, Sarah R.; Fort, James A. & Adkins, Harold E.
System: The UNT Digital Library
The RHIC polarized source upgrade (open access)

The RHIC polarized source upgrade

N/A
Date: October 15, 2013
Creator: A., Zelenski; Atoian, G.; Ritter, J.; Steski, D.; Davydenko, V.; Ivanov, A. et al.
System: The UNT Digital Library
UV Excited Photoacoustic Raman (open access)

UV Excited Photoacoustic Raman

None
Date: November 15, 2013
Creator: Carter, J; Chambers, D; Steele, P; Haugen, P & Heller, D
System: The UNT Digital Library
WET-NZ Multi-Mode Wave Energy Converter Advancement Project (open access)

WET-NZ Multi-Mode Wave Energy Converter Advancement Project

The overall objective of the project was to verify the ocean wavelength functionality of the WET-NZ through targeted hydrodynamic testing at wave tank scale and controlled open sea deployment of a 1/2 scale (1:2) experimental device. This objective was accomplished through a series of tasks designed to achieve four specific goals: Wave Tank Testing to Characterize Hydrodynamic Characteristics;  Open-Sea Testing of a New 1:2 Scale Experimental Model;  Synthesis and Analysis to Demonstrate and Confirm TRL5/6 Status;  Market Impact & Competitor Analysis, Business Plan and Commercialization Strategy.
Date: October 15, 2013
Creator: Kopf, Steven
System: The UNT Digital Library
ADVANCE System Requirements (open access)

ADVANCE System Requirements

N/A
Date: July 15, 2013
Creator: Brown, D. A.; Arcilla, R. & Herman, M.
System: The UNT Digital Library
Polarimetry at RHIC: RHIC polarized beam in Run 2011 (open access)

Polarimetry at RHIC: RHIC polarized beam in Run 2011

N/A
Date: October 15, 2013
Creator: Zelenski, A.
System: The UNT Digital Library
Investigation of WO{sub 3}-Based H{sub 2}S Sensor Materials for Coal Gasification Systems (open access)

Investigation of WO{sub 3}-Based H{sub 2}S Sensor Materials for Coal Gasification Systems

The aim of this project was to engineer the materials studied to enhance the so-called 3S criteria: Sensitivity, Selectivity, and Stability, by using the advantage of controlling structure and properties at nanometer dimensions. It targeted sensor materials that are able to detect poisonous gases resulting from coal-gasification processes, especially sulfur containing emissions. Research findings based on this award demonstrate that doping tungsten oxide (WO{sub 3}) with a small amount of Ti (e.g. 5% in our work) results in a new material that has a higher structural symmetry (e.g. tetragonal morphology) as well as narrower crystalline particle size distribution. As high quality materials with excellent ordered structure and narrower particle-size distributions (which can also withstand high-temperature technological environments such as those encountered in furnaces and coal gasification systems without their structure being affected by phase transformations) are needed for developing new, more sensitive sensor materials, W-Ti-O thin films grown by RF sputtering are valuable candidates for such roles. It is well known that pure WO{sub 3} will change its structure at elevated temperatures. Our work indicates that, Ti doping not only increases the stability of the resultant material by promoting structural phase modifications, but also increases its sensitivity by increasing the …
Date: December 15, 2013
Creator: Manciu, Felicia & Ramana, Chintalapalle
System: The UNT Digital Library
Alternatives to the Maroni Process for Tritium Recovery in Fusion Reactors: Avoiding Volatile Hydrogen Fluoride and High-Temperature High-Speed Rotating Machinery (open access)

Alternatives to the Maroni Process for Tritium Recovery in Fusion Reactors: Avoiding Volatile Hydrogen Fluoride and High-Temperature High-Speed Rotating Machinery

None
Date: October 15, 2013
Creator: Farmer, J.; El-Dasher, B.; Bandhauer, T.; Rubenchik, A.; Reyes, S.; Dunne, M. et al.
System: The UNT Digital Library
Radionuclide Retention in Concrete Wasteforms - FY13 (open access)

Radionuclide Retention in Concrete Wasteforms - FY13

Assessing long-term performance of Category 3 waste cement grouts for radionuclide encasement requires knowledge of the radionuclide-cement interactions and mechanisms of retention (i.e., sorption or precipitation); the mechanism of contaminant release; the significance of contaminant release pathways; how wasteform performance is affected by the full range of environmental conditions within the disposal facility; the process of wasteform aging under conditions that are representative of processes occurring in response to changing environmental conditions within the disposal facility; the effect of wasteform aging on chemical, physical, and radiological properties; and the associated impact on contaminant release. This knowledge will enable accurate prediction of radionuclide fate when the wasteforms come in contact with groundwater. Data collected throughout the course of this work will be used to quantify the efficacy of concrete wasteforms, similar to those used in the disposal of low-level waste and mixed low-level waste, for the immobilization of key radionuclides (i.e., uranium, technetium, and iodine). Data collected will also be used to quantify the physical and chemical properties of the concrete affecting radionuclide retention.
Date: October 15, 2013
Creator: Snyder, Michelle MV; Golovich, Elizabeth C.; Wellman, Dawn M.; Crum, Jarrod V.; Lapierre, Robert; Dage, Denomy C. et al.
System: The UNT Digital Library
Final report for DOE Grant No. DE-SC0006609 - Persistence of Microbially Facilitated Calcite Precipitation as an in situ Treatment for Strontium-90 (open access)

Final report for DOE Grant No. DE-SC0006609 - Persistence of Microbially Facilitated Calcite Precipitation as an in situ Treatment for Strontium-90

Subsurface radionuclide and metal contaminants throughout the U.S. Department of Energy (DOE) complex pose one of DOE?s greatest challenges for long-term stewardship. One promising stabilization mechanism for divalent ions, such as the short-lived radionuclide Sr-90, is co-precipitation in calcite. We have previously found that nutrient addition can stimulate microbial ureolytic activity, that this activity accelerates calcite precipitation and co-precipitation of Sr, and that higher calcite precipitation rates can result in increased Sr partitioning. We have conducted integrated field, laboratory, and computational research to evaluate the relationships between ureolysis and calcite precipitation rates and trace metal partitioning under environmentally relevant conditions, and investigated the coupling between flow/flux manipulations and precipitate distribution. A field experimental campaign conducted at the Integrated Field Research Challenge (IFRC) site located at Rifle, CO was based on a continuous recirculation design; water extracted from a down-gradient well was amended with urea and molasses (a carbon and electron donor) and re-injected into an up-gradient well. The goal of the recirculation design and simultaneous injection of urea and molasses was to uniformly accelerate the hydrolysis of urea and calcite precipitation over the entire inter-wellbore zone. The urea-molasses recirculation phase lasted, with brief interruptions for geophysical surveys, for 12 days …
Date: November 15, 2013
Creator: Smith, Robert W. & Fujita, Yoshiko
System: The UNT Digital Library
Trajectory studies for SPEAR3 LTB (open access)

Trajectory studies for SPEAR3 LTB

None
Date: April 15, 2013
Creator: Sun, Yipeng; Safranek, James & Tian, Kai
System: The UNT Digital Library
Innovative Water Management Technology to Reduce Environment Impacts of Produced Water (open access)

Innovative Water Management Technology to Reduce Environment Impacts of Produced Water

Clemson University with Chevron as an industry partner developed and applied treatment technology using constructed wetland systems to decrease targeted constituents in simulated and actual produced waters to achieve reuse criteria and discharge limits. Pilot-scale and demonstration constructed wetland treatment system (CWTS) experiments led to design strategies for treating a variety of constituents of concern (COCs) in produced waters including divalent metals, metalloids, oil and grease, and ammonia. Targeted biogeochemical pathways for treatment of COCs in pilot-scale CWTS experiments included divalent metal sulfide precipitation through dissimilatory sulfate reduction, metal precipitation through oxidation, reduction of selenite to insoluble elemental selenium, aerobic biodegradation of oil, nitrification of ammonia to nitrate, denitrification of nitrate to nitrogen gas, separation of oil using an oilwater separator, and sorption of ammonia to zeolite. Treatment performance results indicated that CWTSs can be designed and built to promote specific environmental and geochemical conditions in order for targeted biogeochemical pathways to operate. The demonstration system successfully achieved consistent removal extents even while inflow concentrations of COCs in the produced water differed by orders of magnitude. Design strategies used in the pilot-scale and demonstration CWTSs to promote specific conditions that can be applied to designing full-scale CWTSs include plant and …
Date: May 15, 2013
Creator: Castle, James; Rodgers, John; Alley, Bethany; Coffey, Ruthanne; Jurinko, Kristen; Pardue, Michael et al.
System: The UNT Digital Library
241-AZ Farm Annulus Extent of Condition Baseline Inspection (open access)

241-AZ Farm Annulus Extent of Condition Baseline Inspection

This report provides the results of the comprehensive annulus visual inspection for tanks 241- AZ-101 and 241-AZ-102 performed in fiscal year 2013. The inspection established a baseline covering about 95 percent of the annulus floor for comparison with future inspections. Any changes in the condition are also included in this document.
Date: May 15, 2013
Creator: Engeman, Jason K.; Girardot, Crystal L. & Vazquez, Brandon J.
System: The UNT Digital Library
Scientific Data Management Center for Enabling Technologies (open access)

Scientific Data Management Center for Enabling Technologies

Managing scientific data has been identified by the scientific community as one of the most important emerging needs because of the sheer volume and increasing complexity of data being collected. Effectively generating, managing, and analyzing this information requires a comprehensive, end-to-end approach to data management that encompasses all of the stages from the initial data acquisition to the final analysis of the data. Fortunately, the data management problems encountered by most scientific domains are common enough to be addressed through shared technology solutions. Based on community input, we have identified three significant requirements. First, more efficient access to storage systems is needed. In particular, parallel file system and I/O system improvements are needed to write and read large volumes of data without slowing a simulation, analysis, or visualization engine. These processes are complicated by the fact that scientific data are structured differently for specific application domains, and are stored in specialized file formats. Second, scientists require technologies to facilitate better understanding of their data, in particular the ability to effectively perform complex data analysis and searches over extremely large data sets. Specialized feature discovery and statistical analysis techniques are needed before the data can be understood or visualized. Furthermore, interactive …
Date: January 15, 2013
Creator: Vouk, Mladen A.
System: The UNT Digital Library
COMPARISON OF RESULTS FOR QUARTER 4 SURFACE WATER SPLIT SAMPLES COLLECTED AT THE NUCLEAR FUELS SERVICES SITE, ERWIN, TN (open access)

COMPARISON OF RESULTS FOR QUARTER 4 SURFACE WATER SPLIT SAMPLES COLLECTED AT THE NUCLEAR FUELS SERVICES SITE, ERWIN, TN

Oak Ridge Associated Universities (ORAU), under the Oak Ridge Institute for Science and Education (ORISE) contract, collected split surface water samples with Nuclear Fuel Services (NFS) representatives on June 12, 2013. Representatives from the U.S. Nuclear Regulatory Commission (NRC) and the Tennessee Department of Environment and Conservation were also in attendance. Samples were collected at four surface water stations, as required in the approved Request for Technical Assistance number 11-018. These stations included Nolichucky River upstream (NRU), Nolichucky River downstream (NRD), Martin Creek upstream (MCU), and Martin Creek downstream (MCD). Both ORAU and NFS performed gross alpha and gross beta analyses, and Table 1 presents the comparison of results using the duplicate error ratio (DER), also known as the normalized absolute difference. A DER ≤ 3 indicates at a 99% confidence interval that split sample results do not differ significantly when compared to their respective one standard deviation (sigma) uncertainty (ANSI N42.22). The NFS split sample report specifies 95% confidence level of reported uncertainties (NFS 2013). Therefore, standard two sigma reporting values were divided by 1.96. In conclusion, most DER values were less than 3 and results are consistent with low (e.g., background) concentrations. The gross beta result for sample …
Date: August 15, 2013
Creator: unknown
System: The UNT Digital Library
Here be Dragons: The Unexplored Continents of the CMSSM (open access)

Here be Dragons: The Unexplored Continents of the CMSSM

None
Date: May 15, 2013
Creator: Cohen, Timothy & Wacker, Jay G.
System: The UNT Digital Library
Innovative Water Management Technology to Reduce Environment Impacts of Produced Water (open access)

Innovative Water Management Technology to Reduce Environment Impacts of Produced Water

Clemson University with Chevron as an industry partner developed and applied treatment technology using constructed wetland systems to decrease targeted constituents in simulated and actual produced waters to achieve reuse criteria and discharge limits. Pilot-scale and demonstration constructed wetland treatment system (CWTS) experiments led to design strategies for treating a variety of constituents of concern (COCs) in produced waters including divalent metals, metalloids, oil and grease, and ammonia. Targeted biogeochemical pathways for treatment of COCs in pilot-scale CWTS experiments included divalent metal sulfide precipitation through dissimilatory sulfate reduction, metal precipitation through oxidation, reduction of selenite to insoluble elemental selenium, aerobic biodegradation of oil, nitrification of ammonia to nitrate, denitrification of nitrate to nitrogen gas, separation of oil using an oilwater separator, and sorption of ammonia to zeolite. Treatment performance results indicated that CWTSs can be designed and built to promote specific environmental and geochemical conditions in order for targeted biogeochemical pathways to operate. The demonstration system successfully achieved consistent removal extents even while inflow concentrations of COCs in the produced water differed by orders of magnitude. Design strategies used in the pilot-scale and demonstration CWTSs to promote specific conditions that can be applied to designing full-scale CWTSs include plant and …
Date: May 15, 2013
Creator: Castle, James; Rodgers, John; Alley, Bethany; Coffey, Ruthanne; Jurinko, Kristen; Pardue, Michael et al.
System: The UNT Digital Library
Western Kentucky University Research Foundation Biodiesel Project (open access)

Western Kentucky University Research Foundation Biodiesel Project

Petroleum-based liquid hydrocarbons is exclusively major energy source in the transportation sector. Thus, it is the major CO{sub 2} source which is the associated with greenhouse effect. In the United States alone, petroleum consumption in the transportation sector approaches 13.8 million barrels per day (Mbbl/d). It is corresponding to a release of 0.53 gigatons of carbon per year (GtC/yr), which accounts for approximate 7.6 % of the current global release of CO{sub 2} from all of the fossil fuel usage (7 GtC/yr). For the long term, the conventional petroleum production is predicted to peak in as little as the next 10 years to as high as the next 50 years. Negative environmental consequences, the frequently roaring petroleum prices, increasing petroleum utilization and concerns about competitive supplies of petroleum have driven dramatic interest in producing alternative transportation fuels, such as electricity-based, hydrogen-based and bio-based transportation alternative fuels. Use of either of electricity-based or hydrogen-based alternative energy in the transportation sector is currently laden with technical and economical challenges. The current energy density of commercial batteries is 175 Wh/kg of battery. At a storage pressure of 680 atm, the lower heating value (LHV) of H{sub 2} is 1.32 kWh/liter. In contrast, the …
Date: March 15, 2013
Creator: Pan, Wei-Ping & Cao, Yan
System: The UNT Digital Library
Collaborative Proposal: Transforming How Climate System Models are Used: A Global, Multi-Resolution Approach (open access)

Collaborative Proposal: Transforming How Climate System Models are Used: A Global, Multi-Resolution Approach

Despite the great interest in regional modeling for both weather and climate applications, regional modeling is not yet at the stage that it can be used routinely and effectively for climate modeling of the ocean. The overarching goal of this project is to transform how climate models are used by developing and implementing a robust, efficient, and accurate global approach to regional ocean modeling. To achieve this goal, we will use theoretical and computational means to resolve several basic modeling and algorithmic issues. The first task is to develop techniques for transitioning between parameterized and high-fidelity regional ocean models as the discretization grid transitions from coarse to fine regions. The second task is to develop estimates for the error in scientifically relevant quantities of interest that provide a systematic way to automatically determine where refinement is needed in order to obtain accurate simulations of dynamic and tracer transport in regional ocean models. The third task is to develop efficient, accurate, and robust time-stepping schemes for variable spatial resolution discretizations used in regional ocean models of dynamics and tracer transport. The fourth task is to develop frequency-dependent eddy viscosity finite element and discontinuous Galerkin methods and study their performance and effectiveness …
Date: April 15, 2013
Creator: Estep, Donald
System: The UNT Digital Library
Integrated Genome-Based Studies of Shewanella Ecophysiology (open access)

Integrated Genome-Based Studies of Shewanella Ecophysiology

This project had as its goals the understanding of the ecophysiology of the genus Shewanella using various genomics approaches. As opposed to other programs involving Shewanella, this one branched out into the various areas in which Shewanella cells are active, and included both basic and applied studies. All of the work was, to some extent, related to the ability of the bacteria to accomplish electron exchange between the cell and solid state electron acceptors and/or electron donors, a process we call Extracellular Electron Transport, or EET. The major accomplishments related to several different areas: Basic Science Studies: 1. Genetics and genomics of nitrate reduction, resulting in elucidation of atypical nitrate reduction systems in Shewanella oneidensis (MR-1)[2]. 2. Influence of bacterial strain and growth conditions on iron reduction, showing that rates of reduction, extents of reduction, and the formation of secondary minerals were different for different strains of Shewanella [3,4,9]. 3. Comparative genomics as a tool for comparing metabolic capacities of different Shewanella strains, and for predicting growth and metabolism [6,10,15]. In these studies, collaboration with ORNL, PNNL, and 4. Basic studies of electron transport in strain MR-1, both to poised electrodes, and via conductive nanowires [12,13]. This included the first …
Date: October 15, 2013
Creator: Nealson, Kenneth H.
System: The UNT Digital Library