108 Matching Results

Results open in a new window/tab.

Yemen: Background and U.S. Relations (open access)

Yemen: Background and U.S. Relations

With limited natural resources, a crippling illiteracy rate, and high population growth, Yemen faces an array of daunting development challenges that some observers believe make it at risk for becoming a failed state in the next few decades. As the country's population rapidly rises, resources dwindle, and terrorist groups take root in the outlying provinces, the Obama Administration and the 111th Congress are left to grapple with the consequences of Yemeni instability. As President Obama and the 111th Congress reassess U.S. policy toward the Arab world, the opportunity for improved U.S.-Yemeni ties is strong, though recurring tensions over counterterrorism cooperation and lack of U.S. interest in Yemen within the broader foreign policy community persist.
Date: November 1, 2010
Creator: Sharp, Jeremy M.
System: The UNT Digital Library
Dominican Republic: Background and U.S. Relations (open access)

Dominican Republic: Background and U.S. Relations

This report provides background information on current political and economic conditions in the Dominican Republic, as well as an overview of some of the key issues in U.S.-Dominican relations.
Date: November 1, 2010
Creator: Seelke, Clare Ribando
System: The UNT Digital Library
Veterans Affairs: Benefits for Service-Connected Disabilities (open access)

Veterans Affairs: Benefits for Service-Connected Disabilities

This report describes disability compensation, which is a benefit Congress provides to American veterans and their dependents through the United States Department of Veterans Affairs (VA). Disability compensation is a monthly cash benefit program for veterans currently impaired from past service-connected activities.
Date: November 1, 2010
Creator: Weimer, Douglas Reid
System: The UNT Digital Library
The Trans-Pacific Partnership Agreement (open access)

The Trans-Pacific Partnership Agreement

This report discusses the Trans-Pacific Partnership Agreement (TPP), a free trade agreement that includes nations on both sides of the Pacific. Original members of the TPP were Brunei, Chile, New Zealand, and Singapore. The United States, Australia, Peru, and Vietnam have committed themselves to joining and expanding this group. This report discusses similar trade partnerships, the importance of Asia to U.S. trade and security interests, and U.S. participation in the TPP.
Date: November 1, 2010
Creator: Fergusson, Ian F. & Vaughn, Bruce
System: The UNT Digital Library
Microstructural Studies of Uranium-7wt%Molybdenum/Aluminum-2wt%Silicon Dispersion Fuel (open access)

Microstructural Studies of Uranium-7wt%Molybdenum/Aluminum-2wt%Silicon Dispersion Fuel

Document is a thesis.
Date: November 1, 2010
Creator: Miller, Brandon D.
System: The UNT Digital Library
Some Specific CASL Requirements for Advanced Multiphase Flow Simulation of Light Water Reactors (open access)

Some Specific CASL Requirements for Advanced Multiphase Flow Simulation of Light Water Reactors

Because of the diversity of physical phenomena occuring in boiling, flashing, and bubble collapse, and of the length and time scales of LWR systems, it is imperative that the models have the following features: • Both vapor and liquid phases (and noncondensible phases, if present) must be treated as compressible. • Models must be mathematically and numerically well-posed. • The models methodology must be multi-scale. A fundamental derivation of the multiphase governing equation system, that should be used as a basis for advanced multiphase modeling in LWR coolant systems, is given in the Appendix using the ensemble averaging method. The remainder of this work focuses specifically on the compressible, well-posed, and multi-scale requirements of advanced simulation methods for these LWR coolant systems, because without these are the most fundamental aspects, without which widespread advancement cannot be claimed. Because of the expense of developing multiple special-purpose codes and the inherent inability to couple information from the multiple, separate length- and time-scales, efforts within CASL should be focused toward development of a multi-scale approaches to solve those multiphase flow problems relevant to LWR design and safety analysis. Efforts should be aimed at developing well-designed unified physical/mathematical and high-resolution numerical models for compressible, …
Date: November 1, 2010
Creator: Berry, R. A.
System: The UNT Digital Library
International perspectives on mitigating laboratory biorisks. (open access)

International perspectives on mitigating laboratory biorisks.

The International Perspectives on Mitigating Laboratory Biorisks workshop, held at the Renaissance Polat Istanbul Hotel in Istanbul, Republic of Turkey, from October 25 to 27, 2010, sought to promote discussion between experts and stakeholders from around the world on issues related to the management of biological risk in laboratories. The event was organized by Sandia National Laboratories International Biological Threat Reduction program, on behalf of the US Department of State Biosecurity Engagement Program and the US Department of Defense Cooperative Biological Engagement Program. The workshop came about as a response to US Under Secretary of State Ellen O. Tauscher's statements in Geneva on December 9, 2009, during the Annual Meeting of the States Parties to the Biological Weapons Convention (BWC). Pursuant to those remarks, the workshop was intended to provide a forum for interested countries to share information on biorisk management training, standards, and needs. Over the course of the meeting's three days, participants discussed diverse topics such as the role of risk assessment in laboratory biorisk management, strategies for mitigating risk, measurement of performance and upkeep, international standards, training and building workforce competence, and the important role of government and regulation. The meeting concluded with affirmations of the utility …
Date: November 1, 2010
Creator: Pinard, William J. & Salazar, Carlos A.
System: The UNT Digital Library
Experimental Evaluation of Installed Cooking Exhaust Fan Performance (open access)

Experimental Evaluation of Installed Cooking Exhaust Fan Performance

The installed performance of cooking exhaust fans was evaluated through residential field experiments conducted on a sample of 15 devices varying in design and other characteristics. The sample included two rear downdraft systems, two under-cabinet microwave over range (MOR) units, three different installations of an under-cabinet model with grease screens across the bottom and no capture hood, two devices with grease screens covering the bottom of a large capture hood (one under-cabinet, one wall-mount chimney), four under-cabinet open hoods, and two open hoods with chimney mounts over islands. Performance assessment included measurement of airflow and sound levels across fan settings and experiments to quantify the contemporaneous capture efficiency for the exhaust generated by natural gas cooking burners.Capture efficiency is defined as the fraction of generated pollutants that are removed through the exhaust and thus not available for inhalation of household occupants. Capture efficiency (CE) was assessed for various configurations of burner use (e.g., single front, single back, combination of one front and one back, oven) and fan speed setting. Measured airflow rates were substantially lower than the levels noted in product literature for many of the units. This shortfall was observed for several units costing in excess of $1000. Capture …
Date: November 1, 2010
Creator: Singer, Brett C.; Delp, William W. & Apte, Michael G.
System: The UNT Digital Library
Modeling Single Well Injection-Withdrawal (SWIW) Tests for Characterization of Complex Fracture-Matrix Systems (open access)

Modeling Single Well Injection-Withdrawal (SWIW) Tests for Characterization of Complex Fracture-Matrix Systems

The ability to reliably predict flow and transport in fractured porous rock is an essential condition for performance evaluation of geologic (underground) nuclear waste repositories. In this report, a suite of programs (TRIPOLY code) for calculating and analyzing flow and transport in two-dimensional fracture-matrix systems is used to model single-well injection-withdrawal (SWIW) tracer tests. The SWIW test, a tracer test using one well, is proposed as a useful means of collecting data for site characterization, as well as estimating parameters relevant to tracer diffusion and sorption. After some specific code adaptations, we numerically generated a complex fracture-matrix system for computation of steady-state flow and tracer advection and dispersion in the fracture network, along with solute exchange processes between the fractures and the porous matrix. We then conducted simulations for a hypothetical but workable SWIW test design and completed parameter sensitivity studies on three physical parameters of the rock matrix - namely porosity, diffusion coefficient, and retardation coefficient - in order to investigate their impact on the fracture-matrix solute exchange process. Hydraulic fracturing, or hydrofracking, is also modeled in this study, in two different ways: (1) by increasing the hydraulic aperture for flow in existing fractures and (2) by adding a …
Date: November 1, 2010
Creator: Cotte, F.P.; Doughty, C. & Birkholzer, J.
System: The UNT Digital Library
Network discovery, characterization, and prediction : a grand challenge LDRD final report. (open access)

Network discovery, characterization, and prediction : a grand challenge LDRD final report.

This report is the final summation of Sandia's Grand Challenge LDRD project No.119351, 'Network Discovery, Characterization and Prediction' (the 'NGC') which ran from FY08 to FY10. The aim of the NGC, in a nutshell, was to research, develop, and evaluate relevant analysis capabilities that address adversarial networks. Unlike some Grand Challenge efforts, that ambition created cultural subgoals, as well as technical and programmatic ones, as the insistence on 'relevancy' required that the Sandia informatics research communities and the analyst user communities come to appreciate each others needs and capabilities in a very deep and concrete way. The NGC generated a number of technical, programmatic, and cultural advances, detailed in this report. There were new algorithmic insights and research that resulted in fifty-three refereed publications and presentations; this report concludes with an abstract-annotated bibliography pointing to them all. The NGC generated three substantial prototypes that not only achieved their intended goals of testing our algorithmic integration, but which also served as vehicles for customer education and program development. The NGC, as intended, has catalyzed future work in this domain; by the end it had already brought in, in new funding, as much funding as had been invested in it. Finally, the …
Date: November 1, 2010
Creator: Kegelmeyer, W. Philip, Jr.
System: The UNT Digital Library
Ultrathin coatings of nanoporous materials as property enhancements for advanced functional materials. (open access)

Ultrathin coatings of nanoporous materials as property enhancements for advanced functional materials.

This report summarizes the findings of a five-month LDRD project funded through Sandia's NTM Investment Area. The project was aimed at providing the foundation for the development of advanced functional materials through the application of ultrathin coatings of microporous or mesoporous materials onto the surface of substrates such as silicon wafers. Prior art teaches that layers of microporous materials such as zeolites may be applied as, e.g., sensor platforms or gas separation membranes. These layers, however, are typically several microns to several hundred microns thick. For many potential applications, vast improvements in the response of a device could be realized if the thickness of the porous layer were reduced to tens of nanometers. However, a basic understanding of how to synthesize or fabricate such ultra-thin layers is lacking. This report describes traditional and novel approaches to the growth of layers of microporous materials on silicon wafers. The novel approaches include reduction of the quantity of nutrients available to grow the zeolite layer through minimization of solution volume, and reaction of organic base (template) with thermally-oxidized silicon wafers under a steam atmosphere to generate ultra-thin layers of zeolite MFI.
Date: November 1, 2010
Creator: Coker, Eric Nicholas
System: The UNT Digital Library
Boron Nitride Capacitors for Advanced Power Electronic Devices (open access)

Boron Nitride Capacitors for Advanced Power Electronic Devices

This project fabricates long-life boron nitride/boron oxynitride thin film -based capacitors for advanced SiC power electronics with a broad operating temperature range using a physical vapor deposition (PVD) technique. The use of vapor deposition provides for precise control and quality material formation.
Date: November 1, 2010
Creator: Badi, N.; Starikov, D.; Boney, C.; Bensaoula, A. & Johnstone, D.
System: The UNT Digital Library
Assessing Potential Impacts Associated With Contamination Events in Water Distribution Systems : A Sensitivity Analysis. (open access)

Assessing Potential Impacts Associated With Contamination Events in Water Distribution Systems : A Sensitivity Analysis.

An understanding of the nature of the adverse effects that could be associated with contamination events in water distribution systems is necessary for carrying out vulnerability analyses and designing contamination warning systems. This study examines the adverse effects of contamination events using models for 12 actual water systems that serve populations ranging from about 104 to over 106 persons. The measure of adverse effects that we use is the number of people who are exposed to a contaminant above some dose level due to ingestion of contaminated tap water. For this study the number of such people defines the impact associated with an event. We consider a wide range of dose levels in order to accommodate a wide range of potential contaminants. For a particular contaminant, dose level can be related to a health effects level. For example, a dose level could correspond to the median lethal dose, i.e., the dose that would be fatal to 50% of the exposed population. Highly toxic contaminants may be associated with a particular response at a very low dose level, whereas contaminants with low toxicity may only be associated with the same response at a much higher dose level. This report focuses on …
Date: November 1, 2010
Creator: Davis, M. J.; Janke, R. & Taxon, T. N.
System: The UNT Digital Library
NREL's Black Silicon Increases Solar Cell Efficiency by Reducing Reflected Sunlight (Fact Sheet) (open access)

NREL's Black Silicon Increases Solar Cell Efficiency by Reducing Reflected Sunlight (Fact Sheet)

A fact sheet detailing the R&D 100 Award-winning Black Silicon Nanocatalytic Wet-Chemical Etch technology.
Date: November 1, 2010
Creator: unknown
System: The UNT Digital Library
Surface rheology and interface stability. (open access)

Surface rheology and interface stability.

We have developed a mature laboratory at Sandia to measure interfacial rheology, using a combination of home-built, commercially available, and customized commercial tools. An Interfacial Shear Rheometer (KSV ISR-400) was modified and the software improved to increase sensitivity and reliability. Another shear rheometer, a TA Instruments AR-G2, was equipped with a du Nouey ring, bicone geometry, and a double wall ring. These interfacial attachments were compared to each other and to the ISR. The best results with the AR-G2 were obtained with the du Nouey ring. A Micro-Interfacial Rheometer (MIR) was developed in house to obtain the much higher sensitivity given by a smaller probe. However, it was found to be difficult to apply this technique for highly elastic surfaces. Interfaces also exhibit dilatational rheology when the interface changes area, such as occurs when bubbles grow or shrink. To measure this rheological response we developed a Surface Dilatational Rheometer (SDR), in which changes in surface tension with surface area are measured during the oscillation of the volume of a pendant drop or bubble. All instruments were tested with various surfactant solutions to determine the limitations of each. In addition, foaming capability and foam stability were tested and compared with the …
Date: November 1, 2010
Creator: Yaklin, Melissa A.; Cote, Raymond O.; Moffat, Harry K.; Grillet, Anne Mary; Walker, Lynn; Koehler, Timothy P. et al.
System: The UNT Digital Library
Coupled thermomechanical modeling using dissimilar geometries in arpeggio. (open access)

Coupled thermomechanical modeling using dissimilar geometries in arpeggio.

Performing coupled thermomechanical simulations is becoming an increasingly important aspect of nuclear weapon (NW) safety assessments in abnormal thermal environments. While such capabilities exist in SIERRA, they have thus far been used only in a limited sense to investigate NW safety themes. An important limiting factor is the difficulty associated with developing geometries and meshes appropriate for both thermal and mechanical finite element models, which has limited thermomechanical analysis to simplified configurations. This work addresses the issue of how to perform coupled analyses on models where the underlying geometries and associated meshes are different and tailored to their relevant physics. Such an approach will reduce the model building effort and enable previously developed single-physics models to be leveraged in future coupled simulations. A combined-environment approach is presented in this report using SIERRA tools, with quantitative comparisons made between different options in SIERRA. This report summarizes efforts on running a coupled thermomechanical analysis using the SIERRA Arpeggio code.
Date: November 1, 2010
Creator: Kostka, Timothy D. & Templeton, Jeremy Alan
System: The UNT Digital Library
ATR National Scientific User Facility 2009 Annual Report (open access)

ATR National Scientific User Facility 2009 Annual Report

This report describes activities of the ATR NSUF from FY-2008 through FY-2009 and includes information on partner facilities, calls for proposals, users week and education programs. The report also contains project information on university research projects that were awarded by ATR NSUF in the fiscal years 2008 & 2009. This research is university-proposed researcher under a user facility agreement. All intellectual property from these experiments belongs to the university per the user agreement.
Date: November 1, 2010
Creator: Allen, Todd R.; Meyer, Mitchell K.; Marshall, Frances; Thelen, Mary Catherine & Benson, Jeff
System: The UNT Digital Library
FIFTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE (open access)

FIFTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

A series of experiments to monitor the aging performance of Viton{sup reg.} GLT O-rings used in the Model 9975 package has been ongoing for six years at the Savannah River National Laboratory. Sixty-seven mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 F. They were leak-tested initially and have been tested at nominal six month intervals to determine if they meet the criterion of leaktightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 F. High temperature aging continues for 36 GLT O-ring fixtures at 200--350 F. Room temperature leak test failures have been experienced in 5 of the GLT O-ring fixtures aging at 300 and 350 F, and in all 3 of the GLT O-ring fixtures aging at higher temperatures. No failures have yet been observed in GLT O-ring fixtures aging at 200 F for 30--48 months, which is still bounding to O-ring temperatures during storage in KAMS. High temperature aging continues for 6 GLT-S O-ring fixtures at 200--300 F. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures …
Date: November 1, 2010
Creator: Daugherty, W. & Hoffman, E.
System: The UNT Digital Library
Building America Best Practices Series Volume 8: Builders Challenge Quality Criteria Support Document (open access)

Building America Best Practices Series Volume 8: Builders Challenge Quality Criteria Support Document

The U.S. Department of Energy (DOE) has posed a challenge to the homebuilding industry—to build 220,000 high-performance homes by 2012. Through the Builders Challenge, participating homebuilders will have an easy way to differentiate their best energy-performing homes from other products in the marketplace, and to make the benefits clear to buyers. This document was prepared by Pacific Northwest National Laboratory for DOE to provide guidance to U.S. home builders who want to accept the challenge. To qualify for the Builders Challenge, a home must score 70 or less on the EnergySmart Home Scale (E-Scale). The E-scale is based on the well-established Home Energy Rating System (HERS) index, developed by the Residential Energy Services Network (RESNET). The E-scale allows homebuyers to understand – at a glance – how the energy performance of a particular home compares with the performance of others. To learn more about the index and HERS Raters, visit www.natresnet.org. Homes also must meet the Builders Challenge criteria described in this document. To help builders meet the Challenge, guidance is provided in this report for each of the 29 criteria. Included with guidance for each criteria are resources for more information and references for relevant codes and standards. The …
Date: November 1, 2010
Creator: Baechler, Michael C.; Bartlett, Rosemarie & Gilbride, Theresa L.
System: The UNT Digital Library
Filling Knowledge Gaps with Five Fuel Cycle Studies (open access)

Filling Knowledge Gaps with Five Fuel Cycle Studies

During FY 2010, five studies were conducted of technology families’ applicability to various fuel cycle strategies to fill in knowledge gaps in option space and to better understand trends and patterns. Here, a “technology family” is considered to be defined by a type of reactor and by selection of which actinides provide fuel. This report summarizes the higher-level findings; the detailed analyses and results are documented in five individual reports, as follows: • Advanced once through with uranium fuel in fast reactors (SFR), • Advanced once through (uranium fuel) or single recycle (TRU fuel) in high temperature gas cooled reactors (HTGR), • Sustained recycle with Th/U-233 in light water reactors (LWRs), • Sustained recycle with Th/U-233 in molten salt reactors (MSR), and • Several fuel cycle missions with Fusion-Fission Hybrid (FFH). Each study examined how the designated technology family could serve one or more designated fuel cycle missions, filling in gaps in overall option space. Each study contains one or more illustrative cases that show how the technology family could be used to meet a fuel cycle mission, as well as broader information on the technology family such as other potential fuel cycle missions for which insufficient information was available …
Date: November 1, 2010
Creator: Piet, Steven J.; Gehin, Jess; Halsey, William & Taiwo, Temitope
System: The UNT Digital Library
2009 Fuel Cell Market Report, November 2010 (open access)

2009 Fuel Cell Market Report, November 2010

Fuel cells are electrochemical devices that combine hydrogen and oxygen to produce electricity, water, and heat. Unlike batteries, fuel cells continuously generate electricity, as long as a source of fuel is supplied. Moreover, fuel cells do not burn fuel, making the process quiet, pollution-free and two to three times more efficient than combustion. Fuel cell systems can be a truly zero-emission source of electricity, if the hydrogen is produced from non-polluting sources. Global concerns about climate change, energy security, and air pollution are driving demand for fuel cell technology. More than 630 companies and laboratories in the United States are investing $1 billion a year in fuel cells or fuel cell component technologies. This report provides an overview of trends in the fuel cell industry and markets, including product shipments, market development, and corporate performance. It also provides snapshots of select fuel cell companies, including general.
Date: November 1, 2010
Creator: unknown
System: The UNT Digital Library
Systems analysis of decontamination options for civilian vehicles. (open access)

Systems analysis of decontamination options for civilian vehicles.

The objective of this project, which was supported by the Department of Homeland Security (DHS) Science and Technology Directorate (S&T) Chemical and Biological Division (CBD), was to investigate options for the decontamination of the exteriors and interiors of vehicles in the civilian setting in order to restore those vehicles to normal use following the release of a highly toxic chemical. The decontamination of vehicles is especially challenging because they often contain sensitive electronic equipment, multiple materials some of which strongly adsorb chemical agents, and in the case of aircraft, have very rigid material compatibility requirements (i.e., they cannot be exposed to reagents that may cause even minor corrosion). A systems analysis approach was taken examine existing and future civilian vehicle decontamination capabilities.
Date: November 1, 2010
Creator: Foltz, Greg W. & Hoette, Trisha Marie
System: The UNT Digital Library
Evaluation of Shear Strength Threshold of Concern for Retrieval of Interim-Stored K-Basin Sludge in the Hanford Site (open access)

Evaluation of Shear Strength Threshold of Concern for Retrieval of Interim-Stored K-Basin Sludge in the Hanford Site

K-Basin sludge will be recovered into the Sludge Transport and Storage Containers (STSCs) and will be stored in the T Plant for interim storage (at least 10 years). Long-term sludge storage tests conducted by Pacific Northwest National Laboratory show that high uranium content K Basin sludge can self-cement and form a strong sludge with a bulk shear strength of up to 65 kPa. Some of this sludge has "paste" and "chunks" with shear strengths of approximately 3~5 kPa and 380 ~ 770 kPa, respectively. High uranium content sludge samples subjected to hydrothermal testing (e.g., 185°C, 10 h) have been observed to form agglomerates with a shear strength up to 170 kPa. After interim storage at T Plant, the sludge in the STSCs will be mobilized by water jets impinging the sludge. The objective of the evaluation was to determine the range of sludge shear strength for which there is high confidence that a water-jet retrieval system can mobilize stored K-Basin sludge from STSCs. The shear strength at which the sludge can be retrieved is defined as the "shear strength threshold of concern." If the sludge shear strength is greater than the value of the shear strength threshold of concern, a …
Date: November 1, 2010
Creator: Onishi, Yasuo; Yokuda, Satoru T. & Schmidt, Andrew J.
System: The UNT Digital Library