Simulation of a D-T Neutron Source for Neutron ScatteringExperiments (open access)

Simulation of a D-T Neutron Source for Neutron ScatteringExperiments

None
Date: September 29, 2003
Creator: Lou, T. P.; Ludewigt, B. A.; Vujic, J. L. & Leung, K. N.
Object Type: Article
System: The UNT Digital Library
Innovative Concepts Phase I: Inorganic Membranes for CO2/N2 Separation (open access)

Innovative Concepts Phase I: Inorganic Membranes for CO2/N2 Separation

Silica membranes were prepared using a novel technique of catalyzed-atomic layer deposition of silica within a mesoporous matrix. Pyridine was used to catalyze the silicon chloride attachment to the hydroxylated silica surface at room temperature. This half-reaction was followed by the hydration of the surface with water regenerating surface hydroxyls and completing one reaction cycle. The technique resulted in the self-limited pore size reduction of the mesoporous matrix to pore sizes near 1 nm. The self-limited reaction was presumed to be the exclusion of the large catalyst molecule from the pore entrance. In addition to pore size reduction, viscous flow defects were repaired without significantly reducing overall porosity of the membrane. In addition, we investigated the ability of amine-functionalization to enhance the CO{sub 2} transport in silica membranes. Specifically, we examined three synthesis techniques for functionalizing silica membranes with amino groups that resulted in different surface chemistries of the silica membranes. These differences were correlated with changes in the CO{sub 2} facilitation characteristics. It was found that high loadings of amino groups where interaction with the silica surface was minimized promoted the highest CO{sub 2} transport.
Date: September 23, 2003
Creator: Desisto, William
Object Type: Report
System: The UNT Digital Library
Hydration water dynamics and instigation of protein structuralrelaxation (open access)

Hydration water dynamics and instigation of protein structuralrelaxation

Until a critical hydration level is reached, proteins do not function. This critical level of hydration is analogous to a similar lack of protein function observed for temperatures below a dynamical temperature range of 180-220K that also is connected to the dynamics of protein surface water. Restoration of some enzymatic activity is observed in partially hydrated protein powders, sometimes corresponding to less than a single hydration layer on the protein surface, which indicates that the dynamical and structural properties of the surface water is intimately connected to protein stability and function. Many elegant studies using both experiment and simulation have contributed important information about protein hydration structure and timescales. The molecular mechanism of the solvent motion that is required to instigate the protein structural relaxation above a critical hydration level or transition temperature has yet to be determined. In this work we use experimental quasi-elastic neutron scattering (QENS) and molecular dynamics simulation to investigate hydration water dynamics near a greatly simplified protein system. We consider the hydration water dynamics near the completely deuterated N-acetyl-leucine-methylamide (NALMA) solute, a hydrophobic amino acid side chain attached to a polar blocked polypeptide backbone, as a function of concentration between 0.5M-2.0M under ambient conditions. We …
Date: September 1, 2003
Creator: Russo, Daniela; Hura, Greg & Head-Gordon, Teresa
Object Type: Report
System: The UNT Digital Library
Probing Interactions at the Nanoscale: Sensing Protein Molecules (open access)

Probing Interactions at the Nanoscale: Sensing Protein Molecules

Introduction We have developed a high-frequency electronic biosensor of parallel-plate geometry that is embedded within a microfluidic device. This novel biosensor allows us to perform dielectric spectroscopy on a variety of biological samples—from cells to molecules—in solution. Because it is purely electronic, the sensor allows for rapid characterization with no sample preparation or chemical alteration. In addition, it is capable of probing length scales from millimeters to microns over a frequency range 50 MHz to 40 GHz, and sample volumes as small as picoliters [1,2]. Our high-frequency biosensor has evolved from previous device designs based on a coplanar waveguide (CPW) geometry [2]. For our current device, we employ microfluidic tectonics (µFT) [3] to embed two microstrip conductors within a microfluidic channel. The electronic coupling between the two conductors is greater than in our previous CPW design and more importantly, leads to an enhanced sensitivity. Our utilization of µFT allows us to incorporate easily this high-frequency electronic biosensor with a variety of lab-on-a-chip architectures. Device Description Figure 1 is a schematic of our high-frequency electronic biosensor. We fabricate this sensor by first depositing a 500 Å seed layer of gold onto two glass microscope slides. We then use photolithography to pattern …
Date: September 15, 2003
Creator: Sohn, Lydia; Weiss, Ron & Tavazoie, Saeed
Object Type: Report
System: The UNT Digital Library
Rampressor Turbine Design (open access)

Rampressor Turbine Design

The design of a unique gas turbine engine is presented. The first Rampressor Turbine engine rig will be a configuration where the Rampressor rotor is integrated into an existing industrial gas turbine engine. The Rampressor rotor compresses air which is burned in a traditional stationary combustion system in order to increase the enthalpy of the compressed air. The combustion products are then expanded through a conventional gas turbine which provides both compressor and electrical power. This in turn produces shaft torque, which drives a generator to provide electricity. The design and the associated design process of such an engine are discussed in this report.
Date: September 30, 2003
Creator: Systems, Ramgen Power
Object Type: Report
System: The UNT Digital Library
Oak Ridge National Lebroatory Liquid&Gaseous Waste Treatment System Strategic Plan (open access)

Oak Ridge National Lebroatory Liquid&Gaseous Waste Treatment System Strategic Plan

Excellence in Laboratory operations is one of the three key goals of the Oak Ridge National Laboratory (ORNL) Agenda. That goal will be met through comprehensive upgrades of facilities and operational approaches over the next few years. Many of ORNL's physical facilities, including the liquid and gaseous waste collection and treatment systems, are quite old, and are reaching the end of their safe operating life. The condition of research facilities and supporting infrastructure, including the waste handling facilities, is a key environmental, safety and health (ES&H) concern. The existing infrastructure will add considerably to the overhead costs of research due to increased maintenance and operating costs as these facilities continue to age. The Liquid Gaseous Waste Treatment System (LGWTS) Reengineering Project is a UT-Battelle, LLC (UT-B) Operations Improvement Program (OIP) project that was undertaken to develop a plan for upgrading the ORNL liquid and gaseous waste systems to support ORNL's research mission.
Date: September 9, 2003
Creator: Van Hoesen, S. D.
Object Type: Report
System: The UNT Digital Library
CONCEPTUAL DESIGN AND ECONOMICS OF A NOMINAL 500 MWe SECOND-GENERATION PFB COMBUSTION PLANT (open access)

CONCEPTUAL DESIGN AND ECONOMICS OF A NOMINAL 500 MWe SECOND-GENERATION PFB COMBUSTION PLANT

Research has been conducted under United States Department of Energy Contract DE-AC21-86MC21023 to develop a new type of coal-fired plant for electric power generation. This new type of plant, called a Second Generation Pressurized Fluidized Bed Combustion Plant (2nd Gen PFB), offers the promise of efficiencies greater than 48 percent, with both emissions and a cost of electricity that are significantly lower than those of conventional pulverized coal-fired (PC) plants with wet flue gas desulfurization. The 2nd Gen PFB plant incorporates the partial gasification of coal in a carbonizer, the combustion of carbonizer char in a pressurized circulating fluidized bed boiler, and the combustion of carbonizer syngas in a gas turbine combustor to achieve gas turbine inlet temperatures of 2300 F and higher. A conceptual design and an economic analysis was previously prepared for this plant. When operating with a Siemens Westinghouse W501F gas turbine, a 2400psig/1000 F/1000 F/2-1/2 in. Hg. steam turbine, and projected carbonizer, PCFB, and topping combustor performance data, the plant generated 496 MWe of power with an efficiency of 44.9 percent (coal higher heating value basis) and a cost of electricity 22 percent less than a comparable PC plant. The key components of this new type …
Date: September 1, 2003
Creator: Robertson, A.; Goldstein, H.; Horazak, D. & Newby, R.
Object Type: Report
System: The UNT Digital Library
Steel Processing Properties and Their Effect on Impact Deformation of Lightweight Structures (open access)

Steel Processing Properties and Their Effect on Impact Deformation of Lightweight Structures

The objective of the research was to perform a comprehensive computational analysis of the effects of material and process modeling approaches on performance of UltraLight Steel Auto Body (ULSAB) vehicle models. The research addressed numerous material related effects, impact conditions as well as analyzed the performance of the ULSAB vehicles in crashes against designs representing the current US vehicle fleet. This report is organized into three main sections. The first section describes the results of the computational analysis of ULSAB crash simulations that were performed using advanced material modeling techniques. The effects of strain-rate sensitivity on a high strength steel (HSS) intensive vehicle were analyzed. Frontal and frontal offset crash scenarios were used in a finite element parametric study of the ULSAB body structure. Comparisons are made between the crash results using the piece-wise-linear isotropic plasticity strain-rate dependent material model, and the isotropic plasticity material model based on quasi-static properties. The simulation results show the importance of advanced material modeling techniques for vehicle crash simulations due to strain-rate sensitivity and rapid hardening characteristics of advanced high strength steels. Material substitution was investigated for the main frontal crush structure using the material of similar yield stress a significantly different strain-rate and …
Date: September 23, 2003
Creator: Simunovic, S
Object Type: Report
System: The UNT Digital Library
Feed Composition for Sodium-Bearing Waste Treatment Process, Rev. 3 (open access)

Feed Composition for Sodium-Bearing Waste Treatment Process, Rev. 3

Treatment of sodium-bearing waste (SBW) at the Idaho Nuclear Technology and Engineering Center (INTEC) within the Idaho National Engineering and Environmental Laboratory is mandated by a Settlement Agreement between the Department of Energy and the State of Idaho. One of the requirements of the Settlement Agreement is to complete treatment of SBW by December 31, 2012. To support both design and development studies for the SBW treatment process, detailed feed compositions are needed. This report contains the expected compositions of these feed streams and the sources and methods used in obtaining these compositions.
Date: September 1, 2003
Creator: Barnes, Charles Marshall
Object Type: Report
System: The UNT Digital Library
Potential applications of nanostructured materials in nuclear waste management. (open access)

Potential applications of nanostructured materials in nuclear waste management.

This report summarizes the results obtained from a Laboratory Directed Research & Development (LDRD) project entitled 'Investigation of Potential Applications of Self-Assembled Nanostructured Materials in Nuclear Waste Management'. The objectives of this project are to (1) provide a mechanistic understanding of the control of nanometer-scale structures on the ion sorption capability of materials and (2) develop appropriate engineering approaches to improving material properties based on such an understanding.
Date: September 1, 2003
Creator: Braterman, Paul S. (The University of North Texas, Denton, TX); Phol, Phillip Isabio; Xu, Zhi-Ping (The University of North Texas, Denton, TX); Brinker, C. Jeffrey; Yang, Yi (University of New Mexico, Albuquerque, NM); Bryan, Charles R. et al.
Object Type: Report
System: The UNT Digital Library
Solidification of Simulated Liquid Effluents Originating From Sodium-Bearing Waste at the Idaho Nuclear Technology and Engineering Center, FY-03 Report (open access)

Solidification of Simulated Liquid Effluents Originating From Sodium-Bearing Waste at the Idaho Nuclear Technology and Engineering Center, FY-03 Report

In this report, the mechanism and methods of fixation of acidic waste effluents in grout form are explored. From the variations in the pH as a function of total solids addition to acidic waste effluent solutions, the stages of gellation, liquefaction, slurry formation and grout development are quantitatively revealed. Experimental results indicate the completion of these reaction steps to be significant for elimination of bleed liquid and for setting of the grout to a dimensionally stable and hardened solid within a reasonable period of about twenty eight days that is often observed in the cement and concrete industry. The reactions also suggest increases in the waste loading in the direction of decreasing acid molarity. Consequently, 1.0 molar SBW-180 waste is contained in higher quantity than the 2.8 molar SBW-189, given the same grout formulation for both effluents. The variations in the formulations involving components of slag, cement, waste and neutralizing agent are represented in the form of a ternary formulation map. The map in turn graphically reveals the relations among the various formulations and grout properties, and is useful in predicting the potential directions of waste loading in grouts with suitable properties such as slurry viscosity, Vicat hardness, and mechanical …
Date: September 1, 2003
Creator: Raman, S. V.; Herbst, A. K.; Scholes, B. A.; Hinckley, S. H. & Colby, R. D.
Object Type: Report
System: The UNT Digital Library
Delaware Basin Monitoring Annual Report (open access)

Delaware Basin Monitoring Annual Report

The Delaware Basin Drilling Surveillance Program (DBDSP) is designed to monitor drilling activities in the vicinity of the Waste Isolation Pilot Plant (WIPP). This program is based on Environmental Protection Agency (EPA) requirements. The EPA environmental standards for the management and disposal of transuranic (TRU) radioactive waste are codified in 40 CFR Part 191 (EPA 1993). Subparts B and C of the standard address the disposal of radioactive waste. The standard requires the Department of Energy (DOE) to demonstrate the expected performance of the disposal system using a probabilistic risk assessment or performance assessment (PA). This PA must show that the expected repository performance will not release radioactive material above limits set by the EPA's standard. This assessment must include the consideration of inadvertent drilling into the repository at some future time.
Date: September 30, 2003
Creator: Washington Regulatory and Environmental Services
Object Type: Report
System: The UNT Digital Library
Dosimetric Significance of the ICRP's Updated Guidance and Models, 1989-2003, and Implications for U.S. Federal Guidance (open access)

Dosimetric Significance of the ICRP's Updated Guidance and Models, 1989-2003, and Implications for U.S. Federal Guidance

Over the past two decades the U.S. Environmental Protection Agency (EPA) has issued a series of Federal guidance documents for the purpose of providing the Federal and State agencies with technical information to assist their implementation of radiation protection programs. Currently recommended dose conversion factors, annual limits on intake, and derived air concentrations for intake of radionuclides are tabulated in Federal Guidance Report No. 11 (FGR 11), published in 1988. The tabulations in FGR 11 were based on dosimetric quantities and biokinetic and dosimetric models of the International Commission on Radiological Protection (ICRP) developed for application to occupational exposures. Since the publication of FGR 11 the ICRP has revised some of its dosimetric quantities and its models for workers and has also developed age-specific models and dose conversion factors for intake of radionuclides by members of the public. This report examines the extent of the changes in the inhalation and ingestion dose coefficients of FGR 11 implied by the updated recommendations of the ICRP, both for workers and members of the public.
Date: September 10, 2003
Creator: Leggett, R.W.
Object Type: Report
System: The UNT Digital Library
Report on three Genomes to Life Workshops: Data Infrastructure, Modeling and Simulation, and Protein Structure Prediction (open access)

Report on three Genomes to Life Workshops: Data Infrastructure, Modeling and Simulation, and Protein Structure Prediction

On July 22, 23, 24, 2003, three one day workshops were held in Gaithersburg, Maryland. Each was attended by about 30 computational biologists, mathematicians, and computer scientists who were experts in the respective workshop areas The first workshop discussed the data infrastructure needs for the Genomes to Life (GTL) program with the objective to identify gaps in the present GTL data infrastructure and define the GTL data infrastructure required for the success of the proposed GTL facilities. The second workshop discussed the modeling and simulation needs for the next phase of the GTL program and defined how these relate to the experimental data generated by genomics, proteomics, and metabolomics. The third workshop identified emerging technical challenges in computational protein structure prediction for DOE missions and outlining specific goals for the next phase of GTL. The workshops were attended by representatives from both OBER and OASCR. The invited experts at each of the workshops made short presentations on what they perceived as the key needs in the GTL data infrastructure, modeling and simulation, and structure prediction respectively. Each presentation was followed by a lively discussion by all the workshop attendees. The following findings and recommendations were derived from the three workshops. …
Date: September 16, 2003
Creator: Geist, GA
Object Type: Report
System: The UNT Digital Library
Federal Geothermal Research Program Update Fiscal Year 2002 (open access)

Federal Geothermal Research Program Update Fiscal Year 2002

The Department of Energy (DOE) and its predecessors have conducted research and development (R&D) in geothermal energy since 1971. To develop the technology needed to harness the Nation's vast geothermal resources, DOE's Office of Geothermal Technologies oversees a network of national laboratories, industrial contractors, universities, and their subcontractors. The goals are: (1) Double the number of States with geothermal electric power facilities to eight by 2006; (2) Reduce the levelized cost of generating geothermal power to 3-5 cents per kWh by 2007; and (3) Supply the electrical power or heat energy needs of 7 million homes and businesses in the United States by 2010. This Federal Geothermal Program Research Update reviews the specific objectives, status, and accomplishments of DOE's Geothermal Program for Federal Fiscal Year (FY) 2002. The information contained in this Research Update illustrates how the mission and goals of the Office of Geothermal Technologies are reflected in each R&D activity. The Geothermal Program, from its guiding principles to the most detailed research activities, is focused on expanding the use of geothermal energy. balanced strategy for the Geothermal Program.
Date: September 1, 2003
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Interannual Variability in Global Soil Respiration on a 0.5 Degree Grid Cell Basis (1980-1994) (open access)

Interannual Variability in Global Soil Respiration on a 0.5 Degree Grid Cell Basis (1980-1994)

We used a climate-driven regression model to develop spatially resolved estimates of soil-CO{sub 2} emissions from the terrestrial land surface for each month from January 1980 to December 1994, to evaluate the effects of interannual variations in climate on global soil-to-atmosphere CO{sub 2} fluxes. The mean annual global soil-CO{sub 2} flux over this 15-y period was estimated to be 80.4 (range 79.3-81.8) Pg C. Monthly variations in global soil-CO{sub 2} emissions followed closely the mean temperature cycle of the Northern Hemisphere. Globally, soil-CO{sub 2} emissions reached their minima in February and peaked in July and August. Tropical and subtropical evergreen broad-leaved forests contributed more soil-derived CO{sub 2} to the atmosphere than did any other vegetation type ({approx}30% of the total) and exhibited a biannual cycle in their emissions. Soil-CO{sub 2} emissions in other biomes exhibited a single annual cycle that paralleled the seasonal temperature cycle. Interannual variability in estimated global soil-CO{sub 2} production is substantially less than is variability in net carbon uptake by plants (i.e., net primary productivity). Thus, soils appear to buffer atmospheric CO{sub 2} concentrations against far more dramatic seasonal and interannual differences in plant growth. Within seasonally dry biomes (savannas, bushlands, and deserts), interannual variability in …
Date: September 15, 2003
Creator: Raich, J.W.
Object Type: Report
System: The UNT Digital Library
Wood Pulp Digetster Wall Corrosion Investigation (open access)

Wood Pulp Digetster Wall Corrosion Investigation

The modeling of the flow in a wood pulp digester is but one component of the investigation of the corrosion of digesters. This report describes the development of a Near-Wall-Model (NWM) that is intended to couple with a CFD model that determines the flow, heat, and chemical species transport and reaction within the bulk flow of a digester. Lubrication theory approximations were chosen from which to develop a model that could determine the flow conditions within a thin layer near the vessel wall using information from the interior conditions provided by a CFD calculation of the complete digester. The other conditions will be determined by coupled solutions of the wood chip, heat, and chemical species transport and chemical reactions. The NWM was to couple with a digester performance code in an iterative fashion to provide more detailed information about the conditions within the NW region. Process Simulations, Ltd (PSL) is developing the digester performance code. This more detailed (and perhaps more accurate) information from the NWM was to provide an estimate of the conditions that could aggravate the corrosion at the wall. It is intended that this combined tool (NWM-PSL) could be used to understand conditions at/near the wall in …
Date: September 18, 2003
Creator: Giles, GE
Object Type: Report
System: The UNT Digital Library
Alpha Radiolysis of Sorbed Water on Uranium Oxides and Uranium Oxyfluorides (open access)

Alpha Radiolysis of Sorbed Water on Uranium Oxides and Uranium Oxyfluorides

The radiolysis of sorbed water and other impurities contained in actinide oxides has been the focus of a number of studies related to the establishment of criteria for the safe storage and transport of these materials. Gamma radiolysis studies have previously been performed on uranium oxides and oxyfluorides (UO{sub 3}, U{sub 3}O{sub 8}, and UO{sub 2}F{sub 2}) to evaluate the long-term storage characteristics of {sup 233}U. This report describes a similar study for alpha radiolysis. Uranium oxides and oxyfluorides (with {sup 238}U as the surrogate for {sup 233}U) were subjected to relatively high alpha radiation doses (235 to 634 MGy) by doping with {sup 244}Cm. The typical irradiation time for these samples was about 1.5 years, which would be equivalent to more than 50 years irradiation by a {sup 233}U sample. Both dry and wet (up to 10 wt % water) samples were examined in an effort to identify the gas pressure and composition changes that occurred as a result of radiolysis. This study shows that several competing reactions occur during radiolysis, with the net effect that only very low pressures of hydrogen, nitrogen, and carbon dioxide are generated from the water, nitrate, and carbon impurities, respectively, associated with the …
Date: September 10, 2003
Creator: Icenhour, A.S.
Object Type: Report
System: The UNT Digital Library
MOLECULAR DYNAMICS SIMULATIONS OF DISPLACEMENT CASCADES IN MOLYBDENUM (open access)

MOLECULAR DYNAMICS SIMULATIONS OF DISPLACEMENT CASCADES IN MOLYBDENUM

Molecular dynamics calculations have been employed to simulate displacement cascades in neutron irradiated Mo. A total of 90 simulations were conducted for PKA energies between 1 and 40 keV and temperatures from 298 to 923K. The results suggest very little effect of temperature on final defect count and configuration, but do display a temperature effect on peak defect generation prior to cascade collapse. Cascade efficiency, relative to the NRT model, is computed to lie between 1/4 and 1/3 in agreement with simulations performed on previous systems. There is a tendency for both interstitials and vacancies to cluster together following cascade collapse producing vacancy rich regions surrounded by interstitials. Although coming to rest in close proximity, the point defects comprising the clusters generally do not lie within the nearest neighbor positions of one another, except for the formation of dumbbell di-interstitials. Cascades produced at higher PKA energies (20 or 40 keV) exhibit the formation of subcascades.
Date: September 8, 2003
Creator: Smith, Richard Whiting
Object Type: Report
System: The UNT Digital Library
THE EFFECT OF INTERSTITIAL N ON GRAIN BOUNDARY COHESIVE STRENGTH IN Fe (open access)

THE EFFECT OF INTERSTITIAL N ON GRAIN BOUNDARY COHESIVE STRENGTH IN Fe

Increased nitrogen levels have been correlated with decreased ductility and elevated ductile-to-brittle transition temperature in pressure vessel steels [1]. However, the exact role played by nitrogen in the embrittlement of steels remains unclear. Miller and Burke have reported atom probe ion microscopy findings from neutron-irradiated low-alloy pressure vessel steel showing the presence of a 1 to 2 ruonolayer thick film of Mo, N, and C at prior austenitic grain boundaries (GB's) [2], suggesting a role for nitrogen as an intergranular embrittler. It is of interest for the development of mitigation strategies whether nitrogen must combine with other impurities to form nitride precipitates in order to exert an embrittling effect. Briant et al [1] have associated the embrittling effect of N in steels exclusively with intergranular nitride formation. This association suggests that high nitrogen levels may be acceptable if nitride precipitation at grain boundaries is suppressed. To address whether precipitate formation is indeed essential to the N embrittlement process in pressure vessel steel, a computational study was undertaken to ascertain whether the presence of interstitial nitrogen alone could embrittle an Fe GB. If so, nitrogen in any form must be kept completely away from the grain boundaries, if not out of …
Date: September 22, 2003
Creator: Miyoung, Kim; Gellar, Clint B. & Freeman, A. F.
Object Type: Report
System: The UNT Digital Library
PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP: THEORY STUDIES FOR POLARIZED PP SCATTERING (VOLUME 53) (open access)

PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP: THEORY STUDIES FOR POLARIZED PP SCATTERING (VOLUME 53)

In the past two runs of RHIC, the first measurements with polarized proton beams have been performed. For many years to come, the RHIC spin program will offer exciting physics, exploring QCD and the nucleon in new ways. The aim of this small workshop was to attract several spin theorists to the center for about two weeks, in order to collaborate with both experimentalists and theorists at RBRC, and to initiate and/or complete studies of relevance to RHIC spin. A major focus of polarized-pp measurements at RHIC is on measuring the spin-dependent gluon density, {Delta}g. A channel for accessing {Delta}g is high-p{sub T} pion production. The unpolarized cross section for this reaction has been measured by PHENIX and was found in good agreement with a perturbative-QCD based (NLO) calculation. It was a remarkable and exciting coincidence that PHENIX presented also the first results for the spin asymmetry for {rvec p}{rvec p} {yields} {pi}{sup 0}X during this workshop. This sparked a lot of additional activity and discussion. First steps toward the interpretation of the data were taken. Marco Stratmann and Barbara Jager (Regensburg University) presented recent work on the NLO calculation of the polarized cross section and the spin asymmetry, setting …
Date: September 15, 2003
Creator: KRETZER,S. VOGELSANG,W.
Object Type: Report
System: The UNT Digital Library
Reduced Pressure Electron Beam Welding Evaluation Activities on a Ni-Cr-Mo Alloy for Nuclear Waste Packages (open access)

Reduced Pressure Electron Beam Welding Evaluation Activities on a Ni-Cr-Mo Alloy for Nuclear Waste Packages

The current waste package design for the proposed repository at Yucca Mountain Nevada, USA, employs gas tungsten arc welding (GTAW) in fabricating the waste packages. While GTAW is widely used in industry for many applications, it requires multiple weld passes. By comparison, single-pass welding methods inherently use lower heat input than multi-pass welding methods which results in lower levels of weld distortion and also narrower regions of residual stresses at the weld TWI Ltd. has developed a Reduced Pressure Electron Beam (RPEB) welding process which allows EB welding in a reduced pressure environment ({le} 1 mbar). As it is a single-pass welding technique, use of RPEB welding could (1) achieve a comparable or better materials performance and (2) lead to potential cost savings in the waste package manufacturing as compared to GTAW. Results will be presented on the initial evaluation of the RPEB welding on a Ni-Cr-Mo alloy (a candidate alloy for the Yucca Mountain waste packages) in the areas of (a) design and manufacturing simplifications, (b) material performance and (c) weld reliability.
Date: September 11, 2003
Creator: Wong, F.; Punshon, C.; Dorsch, T.; Fielding, P.; Richard, D.; Yang, N. et al.
Object Type: Article
System: The UNT Digital Library
BROOKHAVEN NATIONAL LABORATORY DRAFT INSTITUTIONAL PLAN, FY2004 -- FY2008. (open access)

BROOKHAVEN NATIONAL LABORATORY DRAFT INSTITUTIONAL PLAN, FY2004 -- FY2008.

None
Date: September 23, 2003
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Space Debris-de-Orbiting by Vaporization Impulse using Short Pulse Laser (open access)

Space Debris-de-Orbiting by Vaporization Impulse using Short Pulse Laser

Space debris constitutes a significant hazard to low earth orbit satellites and particularly to manned spacecraft. A quite small velocity decrease from vaporization impulses is enough to lower the perigee of the debris sufficiently for atmospheric drag to de-orbit the debris. A short pulse (picosecond) laser version of the Orion concept can accomplish this task in several years of operation. The ''Mercury'' short pulse Yb:S-FAP laser being developed at LLNL for laser fusion is appropriate for this task.
Date: September 16, 2003
Creator: Early, J; Bibeau, C & Claude, P
Object Type: Article
System: The UNT Digital Library