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Nuclear Waste: DOE Lacks Critical Information Needed to Assess Its Tank Management Strategy at Hanford (open access)

Nuclear Waste: DOE Lacks Critical Information Needed to Assess Its Tank Management Strategy at Hanford

A letter report issued by the Government Accountability Office with an abstract that begins "The Department of Energy (DOE) manages more than 56 million gallons of radioactive and hazardous waste stored in 149 single-shell and 28 double-shell underground tanks at its Hanford Site in Washington State. Many of these aging tanks have already leaked waste into the soil. Meanwhile, DOE's planned process for emptying the tanks and treating the waste--mixing it with molten glass and solidifying it in canisters for storage--has experienced delays, lengthening the time the tanks will store waste and intensifying concerns about the tanks' viability during a long cleanup process. This report addresses (1) the condition, contents, and long-term viability of Hanford's underground tanks; (2) DOE's strategy for managing the tanks; and (3) the extent to which DOE has weighed the risks and benefits of its tank management strategy against the growing costs of that strategy. GAO analyzed numerous studies and reports on the tanks and interviewed DOE officials and other experts on relevant issues."
Date: June 30, 2008
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
Veterans Affairs: Health Information System Modernization Far from Complete; Improved Project Planning and Oversight Needed (open access)

Veterans Affairs: Health Information System Modernization Far from Complete; Improved Project Planning and Oversight Needed

A letter report issued by the Government Accountability Office with an abstract that begins "The Department of Veterans Affairs (VA), through its Veterans Health Administration (VHA), provides health care for more than 5 million veterans each year. In 2001, VHA began an initiative, HealtheVet, to modernize its current medical information system. GAO's objectives were to determine the status of the modernization, VA's overall plan for completing it, and how VA is providing oversight to ensure the success of the initiative. To conduct this review, GAO analyzed project documentation and interviewed officials responsible for the development and implementation of the new system."
Date: June 30, 2008
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
Nuclear Safety: NRC's Oversight of Fire Protection at U.S. Commercial Nuclear Reactor Units Could Be Strengthened (open access)

Nuclear Safety: NRC's Oversight of Fire Protection at U.S. Commercial Nuclear Reactor Units Could Be Strengthened

A letter report issued by the Government Accountability Office with an abstract that begins "After a 1975 fire at the Browns Ferry nuclear plant in Alabama threatened the unit's ability to shut down safely, the Nuclear Regulatory Commission (NRC) issued prescriptive fire safety rules for commercial nuclear units. However, nuclear units with different designs and different ages have had difficulty meeting these rules and have sought exemptions to them. In 2004, NRC began to encourage the nation's 104 nuclear units to transition to a less prescriptive, risk-informed approach that will analyze the fire risks of individual nuclear units. GAO was asked to examine (1) the number and causes of fire incidents at nuclear units since 1995, (2) compliance with NRC fire safety regulations, and (3) the transition to the new approach. GAO visited 10 of the 65 nuclear sites nationwide, reviewed NRC reports and related documentation about fire events at nuclear units, and interviewed NRC and industry officials to examine compliance with existing fire protection rules and the transition to the new approach."
Date: June 30, 2008
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
Long-Term Care Insurance: Oversight of Rate Setting and Claims Settlement Practices (open access)

Long-Term Care Insurance: Oversight of Rate Setting and Claims Settlement Practices

A letter report issued by the Government Accountability Office with an abstract that begins "As the baby boom generation ages, the demand for long-term care services, which include nursing home care, is likely to grow and could strain state and federal resources. The increased use of long-term care insurance (LTCI) may be a way of reducing the share of long-term care paid by state and federal governments. Oversight of LTCI is primarily the responsibility of states, but over the past 12 years, there have been federal efforts to increase the use of LTCI while also ensuring that consumers purchasing LTCI are adequately protected. Despite this oversight, concerns have been raised about both premium increases and denials of claims that may leave consumers without LTCI coverage when they begin needing care. GAO was asked to review the consumer protection standards governing LTCI policies and how those standards are being enforced. Specifically, GAO examined oversight of the LTCI industry's (1) rate setting practices and (2) claims settlement practices. GAO reviewed information from the National Association of Insurance Commissioners (NAIC) on all states' rate setting standards. GAO also completed 10 state case studies on oversight of rate setting and claims settlement practices, which …
Date: June 30, 2008
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
Commercial Drivers: Certification Process for Drivers with Serious Medical Conditions (open access)

Commercial Drivers: Certification Process for Drivers with Serious Medical Conditions

A letter report issued by the Government Accountability Office with an abstract that begins "Millions of drivers hold commercial driver licenses (CDL), allowing them to operate commercial vehicles. The Department of Transportation (DOT) established regulations requiring medical examiners to certify that these drivers are medically fit to operate their vehicles and provides oversight of their implementation. Little is known on the extent to which individuals with serious medical conditions hold CDLs. GAO was asked to (1) examine the extent to which individuals holding a current CDL have serious medical conditions and (2) provide examples of commercial drivers with medical conditions that should disqualify them from receiving a CDL. To examine the extent to which individuals holding CDLs have serious medical conditions, GAO identified those who were in both DOT's CDL database and selected federal disability databases of the Social Security Administration, Office of Personnel Management, and Departments of Veterans Affairs and Labor and have been identified as 100 percent disabled according to the program's criteria. Because DOT's data also include inactive licenses, GAO obtained current CDL data from 12 selected states based primarily on the size of CDL population. To provide case study examples, GAO focused on four states--Florida, Maryland, …
Date: June 30, 2008
Creator: United States. Government Accountability Office.
System: The UNT Digital Library
Atmospheric Properties from the 2006 Niamey Deployment and Climate Simulation with a Geodesic Grid Coupled Climate Model Third Quarter 2008 (open access)

Atmospheric Properties from the 2006 Niamey Deployment and Climate Simulation with a Geodesic Grid Coupled Climate Model Third Quarter 2008

In 2008, the Atmospheric Radiation Measurement (ARM) Program and the Climate Change Prediction Program (CCPP) have been asked to produce joint science metrics. For CCPP, the metrics will deal with a decade-long control simulation using geodesic grid-coupled climate model. For ARM, the metrics will deal with observations associated with the 2006 deployment of the ARM Mobile Facility (AMF) to Niamey, Niger. Specifically, ARM has been asked to deliver data products for Niamey that describe cloud, aerosol, and dust properties. This report describes the aerosol optical depth (AOD) product.
Date: June 30, 2008
Creator: Mather, JH; Randall, DA & Flynn, CJ
System: The UNT Digital Library
Commercial Off-the-Shelf (COTS) Components and Enterprise Component Information System (eCIS) (open access)

Commercial Off-the-Shelf (COTS) Components and Enterprise Component Information System (eCIS)

The purpose of the project was to develop the processes for using commercial off-the-shelf (COTS) parts for WR production and to put in place a system for implementing the data management tools required to disseminate, store, track procurement, and qualify vendors. Much of the effort was devoted to determining if the use of COTS parts was possible. A basic question: How does the Nuclear Weapons Complex (NWC) begin to use COTS in the weapon Stockpile Life Extension Programs with high reliability, affordability, while managing risk at acceptable levels? In FY00, it was determined that a certain weapon refurbishment program could not be accomplished without the use of COTS components. The elements driving the use of COTS components included decreased cost, greater availability, and shorter delivery time. Key factors that required implementation included identifying the best suppliers and components, defining life cycles and predictions of obsolescence, testing the feasibility of using COTS components with a test contractor to ensure capability, as well as quality and reliability, and implementing the data management tools required to disseminate, store, track procurement, and qualify vendors. The primary effort of this project then was to concentrate on the risks involved in the use of COTS and …
Date: June 30, 2008
Creator: Minihan, John; Schmidt, Ed; Enserro, Greg & Thompson, Melissa
System: The UNT Digital Library
A Bio-Based Fuel Cell for Distributed Energy Generation (open access)

A Bio-Based Fuel Cell for Distributed Energy Generation

The technology we propose consists primarily of an improved design for increasing the energy density of a certain class of bio-fuel cell (BFC). The BFCs we consider are those which harvest electrons produced by microorganisms during their metabolism of organic substrates (e.g. glucose, acetate). We estimate that our technology will significantly enhance power production (per unit volume) of these BFCs, to the point where they could be employed as stand-alone systems for distributed energy generation.
Date: June 30, 2008
Creator: Terrinoni, Anthony & Gifford, Sean
System: The UNT Digital Library
Wide-Area Energy Storage and Management system to Balance Intermittent Resources in the Bonneville Power Administration and California ISO Control Areas (open access)

Wide-Area Energy Storage and Management system to Balance Intermittent Resources in the Bonneville Power Administration and California ISO Control Areas

The entire project addresses the issue of mitigating additional intermittency and fast ramps that occur at higher penetration of intermittent resources, including wind genera-tion, in the Bonneville Power Administration (BPA) and the California Independent Sys-tem Operator (California ISO) control areas. The proposed Wide Area Energy Storage and Management System (WAEMS) will address the additional regulation requirement through the energy exchange between the participating control areas and through the use of energy storage and other generation resources. For the BPA and California ISO control centers, the new regulation service will look no different comparing with the traditional regulation resources. The proposed project will benefit the regulation service in these service areas, regardless of the actual degree of penetration of the intermittent resources in the regions. The project develops principles, algorithms, market integration rules, functional de-sign and technical specifications for the WAEMS system. The project is sponsored by BPA and supported in kind by California ISO, Beacon Power Corporation, and the Cali-fornia Energy Commission (CEC).
Date: June 30, 2008
Creator: Makarov, Yuri V.; Yang, Bo; DeSteese, John G.; Lu, Shuai; Miller, Carl H.; Nyeng, Preben et al.
System: The UNT Digital Library
Hierarchical Adaptive Solution of Radiation Transport Problems on Unstructured Grids (open access)

Hierarchical Adaptive Solution of Radiation Transport Problems on Unstructured Grids

Computational radiation transport has steadily gained acceptance in the last decade as a viable modeling tool due to the rapid advancements in computer software and hardware technologies. It can be applied for the analysis of a wide range of problems which arise in nuclear reactor physics, medical physics, atmospheric physics, astrophysics and other areas of engineering physics. However, radiation transport is an extremely chanllenging computational problem since the governing equation is seven-deimensional (3 in space, 2 in direction, 1 in energy, and 1 in time) with a high degree of coupleing betwen these variables. If not careful, this relatively large number of independent variables when discretized can potentially lead to sets of linear equations of intractable size. Though parallel computing has allowed the solution of very large problems, avaliable computational resources will always be finite due to the fact that every more sophisticated multiphysics models are being demanded by industry. There is thus the pressing requirement to optimize the discretizations so as to minimize the effort and maximize the accuracy.
Date: June 30, 2008
Creator: Oliveira, Dr. Cassiano R. E de
System: The UNT Digital Library
Reduction of Water Use in Wet FGD Systems (open access)

Reduction of Water Use in Wet FGD Systems

Cooperative Agreement DE-FC26-06NT42726 was established in January 2006, and is current through Amendment 2, April 2006. The current reporting period, April 1, 2008 through June 30, 2008, is the eighth progress-reporting period for the project. However, this report will be the final report (instead of a quarterly report) because this project is being terminated. Efforts to bring this project to a close over the past several months focused on internal project discussions, and subsequent communications with NETL, regarding the inherent difficulty with completing this project as originally scoped, and the option of performing an engineering study to accomplish some of the chief project objectives. However, NETL decided that the engineering study did indeed constitute a significant scope deviation from the original concepts, and that pursuit of this option was not recommended. These discussions are summarized in the Results and Discussion, and the Conclusion sections. The objective of this project by a team lead by URS Group was to demonstrate the use of regenerative heat exchange to reduce flue gas temperature and minimize evaporative water consumption in wet flue gas desulphurization (FGD) systems on coal-fired boilers. Furthermore, the project intended to demonstrate that regenerative heat exchange to cool flue gas upstream …
Date: June 30, 2008
Creator: Rencher, David
System: The UNT Digital Library
Imaging Reservoir Quality: Seismic Signatures of Geologic Processes (open access)

Imaging Reservoir Quality: Seismic Signatures of Geologic Processes

Lithofacies successions from diverse depositional environments show distinctive patterns in various rock-physics planes (velocity-porosity, velocity-density and porosity-clay). Four clear examples of decameter-scale lithofacies sequences are documented in this study: (1) Micocene fluvial deposits show an inverted-V pattern indicative of dispersed fabric, (2) a fining-upward sequence of mud-rich deep deposits shows a linear trend associated with laminated sand-clay mixtures, (3) sand-rich deposits show a pattern resulting from the scarcity of mixed lithofacies, and (4) a coarsening-upward sequence shows evidence of both dispersed and horizontally laminated mixed lithofacies, with predominating dispersed mixtures generated by bioturbation. It was observed that carbonate-cemented sandstones are extremely heterogeneous in the project deep-water study area. Those from the base of incisions are usually associated with lower shaliness, lower porosity and higher P-impedance, while from the top of flooding surfaces exhibit higher shaliness, higher porosity and lower P-impedance. One rock physics model that captures the observed impedance-porosity trend is the 'stiff-sand model'. For this model, the high-porosity end-member is unconsolidated sand whose initial porosity is a function of sorting and shaliness, while the low-porosity end-member is solid mineral. These two end points are joined with a Hashin-Shtrikman equation. A systematic variation of quartz:clay ratio from proximal to distal …
Date: June 30, 2008
Creator: Stanford University. Department of Geophysics.
System: The UNT Digital Library
Fundamental Studies of Ignition Process in Large Natural Gas Engines Using Laser Spark Ignition (open access)

Fundamental Studies of Ignition Process in Large Natural Gas Engines Using Laser Spark Ignition

Past research has shown that laser ignition provides a potential means to reduce emissions and improve engine efficiency of gas-fired engines to meet longer-term DOE ARES (Advanced Reciprocating Engine Systems) targets. Despite the potential advantages of laser ignition, the technology is not seeing practical or commercial use. A major impediment in this regard has been the 'open-path' beam delivery used in much of the past research. This mode of delivery is not considered industrially practical owing to safety factors, as well as susceptibility to vibrations, thermal effects etc. The overall goal of our project has been to develop technologies and approaches for practical laser ignition systems. To this end, we are pursuing fiber optically coupled laser ignition system and multiplexing methods for multiple cylinder engine operation. This report summarizes our progress in this regard. A partial summary of our progress includes: development of a figure of merit to guide fiber selection, identification of hollow-core fibers as a potential means of fiber delivery, demonstration of bench-top sparking through hollow-core fibers, single-cylinder engine operation with fiber delivered laser ignition, demonstration of bench-top multiplexing, dual-cylinder engine operation via multiplexed fiber delivered laser ignition, and sparking with fiber lasers. To the best of our …
Date: June 30, 2008
Creator: Yalin, Azer & Willson, Bryan
System: The UNT Digital Library
Technology demonstration for reducing mercury emissions from small-scale gold refining facilities. (open access)

Technology demonstration for reducing mercury emissions from small-scale gold refining facilities.

Gold that is brought from artisanal and small-scale gold mining areas to gold shops for processing and sale typically contains 5-40% mercury. The uncontrolled removal of the residual mercury in gold shops by using high-temperature evaporation can be a significant source of mercury emissions in urban areas where the shops are located. Emissions from gold shop hoods during a burn can exceed 1,000 mg/m{sup 3}. Because the saturation concentration of mercury vapor at operating temperatures at the hood exhaust is less than 100 mg/m{sup 3}, the dominant component of the exhaust is in the form of aerosol or liquid particles. The U.S. Environmental Protection Agency (EPA), with technical support from Argonne National Laboratory (Argonne), has completed a project to design and test a technology to remove the dominant aerosol component in the emissions from gold shops. The objective was to demonstrate a technology that could be manufactured at low cost and by using locally available materials and manufacturing capabilities. Six prototypes designed by Argonne were locally manufactured, installed, and tested in gold shops in Itaituba and Creporizao, Brazil. The initial prototype design incorporated a pebble bed as the media for collecting the mercury aerosols, and a mercury collection efficiency of …
Date: June 30, 2008
Creator: Habegger, L. J.; Fernandez, L. E.; Engle, M.; Bailey, J. L.; Peterson, D. P.; MacDonell, M. M. et al.
System: The UNT Digital Library
FTR GO14246 (open access)

FTR GO14246

The Maine Forest Bioproducts Research and Development project originally focused on the State’s interest in the development of an integrated forest products refinery (IFPR). The original intent was that Research and Development (R&D) funded by this award will allow Maine to refine its strategy and pursue development of an integrated biorefinery. Activities were to be divided into three major R&D projects: (a) Establish the potential for a forest products biorefinery in Maine, by determining the technical and economic feasibility and resource availability. (b) Investigate and develop conversion processes for forest bioproducts to utilize the sugars available from hemicellulose. Research projects will determine how to best utilize refinery waste streams to recover heat value and recycle remaining components. (c) Cost share very early stage R&D efforts to engage the private sector and stimulate innovative efforts that will build upon the research efforts in (b) above, utilize the information gleaned from (a), and lead to commercialization of new products or services and development of the forest bioproducts industrial sector in Maine.
Date: June 30, 2008
Creator: Bentley, Martha
System: The UNT Digital Library
Microhole Coiled Tubing Bottom Hole Assemblies (open access)

Microhole Coiled Tubing Bottom Hole Assemblies

The original objective of the project, to deliver an integrated 3 1/8-inch diameter Measurement While Drilling (MWD) and Logging While Drilling (LWD) system for drilling small boreholes using coiled tubing drilling, has been achieved. Two prototype systems have been assembled and tested in the lab. One of the systems has been successfully tested downhole in a conventional rotary drilling environment. Development of the 3 1/8-inch system has also lead to development and commercialization of a slightly larger 3.5-inch diameter system. We are presently filling customer orders for the 3.5-inch system while continuing with commercialization of the 3 1/8-inch system. The equipment developed by this project will be offered for sale to multiple service providers around the world, enabling the more rapid expansion of both coiled tubing drilling and conventional small diameter drilling. The project was based on the reuse of existing technology whenever possible in order to minimize development costs, time, and risks. The project was begun initially by Ultima Labs, at the time a small company ({approx}12 employees) which had successfully developed a number of products for larger oil well service companies. In September, 2006, approximately 20 months after inception of the project, Ultima Labs was acquired by Sondex …
Date: June 30, 2008
Creator: Macune, Don
System: The UNT Digital Library
Final Report: Operational Retrieval of Cloud Microphysical Properties Using Combined Measurements by Diverse Instruments (open access)

Final Report: Operational Retrieval of Cloud Microphysical Properties Using Combined Measurements by Diverse Instruments

The report on the final phase of the project describes improvements in the ice and liquid cloud retrieval algorithms due to the use of three-parameter particle size distributions in which all three parameters may vary with height, testing of the improved retrievals by comparisons of measured and calculated fluxes, and further improvement in liquid retrievals obtained by adding liquid water path information from the microwave radiometer to radar and visible optical depth information.
Date: June 30, 2008
Creator: Austin, Richard T.
System: The UNT Digital Library
Nuclear Reactor Power Monitoring Using Silicon Carbide Semiconductor Radiation Detectors (open access)

Nuclear Reactor Power Monitoring Using Silicon Carbide Semiconductor Radiation Detectors

Define Generation IV Reactor Power Monitoring Requirements.
Date: June 30, 2008
Creator: Blue, Thomas & Miller, Don
System: The UNT Digital Library
Evaluation of Sorbent Injection for Mercury Control: Final Report (open access)

Evaluation of Sorbent Injection for Mercury Control: Final Report

ADA-ES, Inc., with support from DOE/NETL, EPRI, and industry partners, studied mercury control options at six coal-fired power plants. The overall objective of the this test program was to evaluate the capabilities of activated carbon injection at six plants: Sunflower Electric's Holcomb Station Unit 1, AmerenUE's Meramec Station Unit 2, Missouri Basin Power Project's Laramie River Station Unit 3, Detroit Edison's Monroe Power Plant Unit 4, American Electric Power's Conesville Station Unit 6, and Labadie Power Plant Unit 2. These plants have configurations that together represent 78% of the existing coal-fired generation plants. The financial goals for the program established by DOE/NETL were to reduce the uncontrolled mercury emissions by 50 to 70% at a cost 25 to 50% lower than the target established by DOE of $60,000 per pound of mercury removed. Results from testing at Holcomb, Laramie, Meramec, Labadie, and Monroe indicate the DOE goal was successfully achieved. However, further improvements for plants with conditions similar to Conesville are recommended that would improve both mercury removal performance and economics.
Date: June 30, 2008
Creator: Sjostrom, Sharon
System: The UNT Digital Library
Base Program on Energy Related Research (open access)

Base Program on Energy Related Research

The main objective of the Base Research Program was to conduct both fundamental and applied research that will assist industry in developing, deploying, and commercializing efficient, nonpolluting fossil energy technologies that can compete effectively in meeting the energy requirements of the Nation. In that regard, tasks proposed under the WRI research areas were aligned with DOE objectives of secure and reliable energy; clean power generation; development of hydrogen resources; energy efficiency and development of innovative fuels from low and no-cost sources. The goal of the Base Research Program was to develop innovative technology solutions that will: (1) Increase the production of United States energy resources--coal, natural gas, oil, and renewable energy resources; (2) Enhance the competitiveness of United States energy technologies in international markets and assist in technology transfer; (3) Reduce the nation's dependence on foreign energy supplies and strengthen both the United States and regional economies; and (4) Minimize environmental impacts of energy production and utilization. This report summarizes the accomplishments of the overall Base Program. This document represents a stand-alone Final Report for the entire Program. It should be noted that an interim report describing the Program achievements was prepared in 2003 covering the progress made under various …
Date: June 30, 2008
Creator: Institute, Western Research
System: The UNT Digital Library
Investigation of Pressurized Entrained-Flow Kraft Black Liquor Gasification in an Industrially Relevant Environment (open access)

Investigation of Pressurized Entrained-Flow Kraft Black Liquor Gasification in an Industrially Relevant Environment

The University of Utah's project 'Investigation of Pressurized Entrained-Flow Kraft Black Liquor Gasification in an Industrially Relevant Environment' (U.S. DOE Cooperative Agreement DE-FC26-04NT42261) was a response to U.S. DOE/NETL solicitation DE-PS36-04GO94002, 'Biomass Research and Development Initiative' Topical Area 4-Kraft Black Liquor Gasification. The project began September 30, 2004. The objective of the project was to improve the understanding of black liquor conversion in high pressure, high temperature reactors that gasify liquor through partial oxidation with either air or oxygen. The physical and chemical characteristics of both the gas and condensed phase were to be studied over the entire range of liquor conversion, and the rates and mechanisms of processes responsible for converting the liquor to its final smelt and syngas products were to be investigated. This would be accomplished by combining fundamental, lab-scale experiments with measurements taken using a new semi-pilot scale pressurized entrained-flow gasifier. As a result of insufficient availability of funds and changes in priority within the Office of Biomass Programs of the U.S. Department of Energy, the research program was terminated in its second year. In total, only half of the budgeted funding was made available for the program, and most of this was used during the …
Date: June 30, 2008
Creator: Whitty, Kevin
System: The UNT Digital Library
Intermediate Temperature Solid Oxide Fuel Cell Development (open access)

Intermediate Temperature Solid Oxide Fuel Cell Development

Solid oxide fuel cells (SOFCs) are high efficiency energy conversion devices. Present materials set, using yttria stabilized zirconia (YSZ) electrolyte, limit the cell operating temperatures to 800 C or higher. It has become increasingly evident however that lowering the operating temperature would provide a more expeditious route to commercialization. The advantages of intermediate temperature (600 to 800 C) operation are related to both economic and materials issues. Lower operating temperature allows the use of low cost materials for the balance of plant and limits degradation arising from materials interactions. When the SOFC operating temperature is in the range of 600 to 700 C, it is also possible to partially reform hydrocarbon fuels within the stack providing additional system cost savings by reducing the air preheat heat-exchanger and blower size. The promise of Sr and Mg doped lanthanum gallate (LSGM) electrolyte materials, based on their high ionic conductivity and oxygen transference number at the intermediate temperature is well recognized. The focus of the present project was two-fold: (a) Identify a cell fabrication technique to achieve the benefits of lanthanum gallate material, and (b) Investigate alternative cathode materials that demonstrate low cathode polarization losses at the intermediate temperature. A porous matrix supported, …
Date: June 30, 2008
Creator: Elangovan, S.; Barnett, Scott & Haile, Sossina
System: The UNT Digital Library
ADVANCED INTEGRATION OF MULTI-SCALE MECHANICS AND WELDING PROCESS SIMULATION IN WELD INTEGRITY ASSESSMENT (open access)

ADVANCED INTEGRATION OF MULTI-SCALE MECHANICS AND WELDING PROCESS SIMULATION IN WELD INTEGRITY ASSESSMENT

The potential to save trillions of BTU’s in energy usage and billions of dollars in cost on an annual basis based on use of higher strength steel in major oil and gas transmission pipeline construction is a compelling opportunity recognized by both the US Department of Energy (DOE). The use of high-strength steels (X100) is expected to result in energy savings across the spectrum, from manufacturing the pipe to transportation and fabrication, including welding of line pipe. Elementary examples of energy savings include more the 25 trillion BTUs saved annually based on lower energy costs to produce the thinner-walled high-strength steel pipe, with the potential for the US part of the Alaskan pipeline alone saving more than 7 trillion BTU in production and much more in transportation and assembling. Annual production, maintenance and installation of just US domestic transmission pipeline is likely to save 5 to 10 times this amount based on current planned and anticipated expansions of oil and gas lines in North America. Among the most important conclusions from these studies were: • While computational weld models to predict residual stress and distortions are well-established and accurate, related microstructure models need improvement. • Fracture Initiation Transition Temperature (FITT) …
Date: June 30, 2008
Creator: Wilkowski, Gery M.; Rudland, David L.; Shim, Do-Jun; Brust, Frederick W. & Babu, Sundarsanam
System: The UNT Digital Library
NEXT GENERATION NEUTRON SCINTILLATORS BASED ON SEMICONDUCTOR NANOSTRUCTURES (open access)

NEXT GENERATION NEUTRON SCINTILLATORS BASED ON SEMICONDUCTOR NANOSTRUCTURES

The results reported here successfully demonstrate the technical feasibility of ZnS QDs/{sup 6}LiF/polymer composites as thermal neutron scintillators. PartTec has obtained stable ZnS QDs with a quantum yield of 17% induced by UV light, and light pulse decay lifetimes of 10-30 ns induced by both UV and neutrons. These lifetime values are much shorter than those of commercial ZnS microparticle and {sup 6}Li-glass scintillators. Clear pulse height peaks induced by neutron irradiation were seen for PartTec's ZnS nanocomposites. By adjusting the concentrations, particle size and degree of dispersion of ZnS QD/{sup 6}LiF in a PVA matrix, the light absorption and light yield of films at 420-440 nm can be optimized. PartTec's novel scintillators will replace traditional {sup 6}Li-glass and ZnS/{sup 6}LiF:Ag scintillators if the PL quantum yield can be improved above 30%, and/or increase the transparency of present nanoscintillators. Time and resources inhibited PartTec's total success in Phase I. For example, bulk doping preparations of ZnS QDs with Ag{sup +}, Eu{sup 3+} or Ce{sup 3+} QDs was impractical given those constraints, nor did they permit PartTec to measure systematically the change of PL decay lifetimes in different samples. PartTec will pursue these studies in the current proposal, as well as …
Date: June 30, 2008
Creator: Wang, Cai-Lin
System: The UNT Digital Library