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Updating the Nrc Guidance for Human Factors Engineering Reviews. (open access)

Updating the Nrc Guidance for Human Factors Engineering Reviews.

None
Date: September 15, 2002
Creator: O Hara, J. M.; Brown, W. S.; Higgins, J. C.; Persensky, J. J.; Lewis, P. M. & Bongarra, J.
System: The UNT Digital Library
Advances in Low-Defect Multilayers for EUVL Mask Blanks (open access)

Advances in Low-Defect Multilayers for EUVL Mask Blanks

Low-defect multilayer coatings are required to fabricate mask blanks for Extreme Ultraviolet Lithography (EUVL). The mask blanks consist of high reflectance E W multilayers on low thermal expansion substrates. A defect density of 0.0025 printable defects/cm{sup 2} for both the mask substrate and the multilayer is required to provide a mask blank yield of 60%. Current low defect multilayer coating technology allows repeated coating-added defect levels of 0.05/cm{sup 2} for defects greater than 90 nm polystyrene latex sphere (PSL) equivalent size for lots of 20 substrates. Extended clean operation of the coating system at levels below 0.08/cm{sup 2} for 3 months of operation has also been achieved. Two substrates with zero added defects in the quality area have been fabricated, providing an existence proof that ultra low defect coatings are possible. Increasing the ion source-to-target distance from 410 to 560 mm to reduce undesired coating of the ion source caused the defect density to increase to 0.2/cm{sup 2}. Deposition and etching diagnostic witness substrates and deposition pinhole cameras showed a much higher level of ion beam spillover (ions missing the sputter target) than expected. Future work will quantify beam spillover, and test designs to reduce spillover, if it is confirmed …
Date: April 15, 2002
Creator: Folta, J. A.; Davidson, J. C.; Larson, C. C.; Walton, C. C. & Kearney, P. A.
System: The UNT Digital Library
The Computational Complexity of the Minimum Degree Algorithm (open access)

The Computational Complexity of the Minimum Degree Algorithm

The Minimum Degree algorithm, one of the classical algorithms of sparse matrix computations, is widely used to order graphs to reduce the work and storage needed to solve sparse systems of linear equations. There has been extensive research involving practical implementations of this algorithm over the past two decades. However, little has been done to establish theoretical bounds on the computational complexity of these implementations. We study the Minimum Degree algorithm, and prove time complexity bounds for its widely used variants.
Date: May 15, 2002
Creator: Heggernes, P; Eisenstat, S C; Kumfert, G & Pothen, A
System: The UNT Digital Library
Supersymmetry and the Cosmic Ray Positron Excess (open access)

Supersymmetry and the Cosmic Ray Positron Excess

We explore several supersymmetric alternatives to explain predictions for the cosmic ray positron excess. Light sneutrino or neutralino LSP's, and a fine-tuned model designed to provide a delta-function input, can give adequate statistical descriptions of the reported HEAT data if non-thermal production of the relic cold dark matter density dominates and/or if"boost factors" (that could originate in uncertainties from propagation or local density fluctuations) to increase the size of the signal are included. All the descriptions can be tested at the Tevatron or LHC, and some in other WIMP detecting experiments.
Date: February 15, 2002
Creator: Kane, Gordon L.; Wang, Lian-Tao & Wang, Ting T.
System: The UNT Digital Library
Linkage and association of haplotypes at the APOA1/C3/A4/A5 genecluster to familial combined hyperlipidemia (open access)

Linkage and association of haplotypes at the APOA1/C3/A4/A5 genecluster to familial combined hyperlipidemia

Combined hyperlipidemia (CHL) is a common disorder of lipidmetabolism that leads to an increased risk of cardiovascular disease. Thelipid profile of CHL is characterised by high levels of atherogeniclipoproteins and low levels of high-density-lipoprotein-cholesterol.Apolipoprotein (APO) A5 is a newly discovered gene involved in lipidmetabolism located within 30kbp of the APOA1/C3/A4 gene cluster. Previousstudies have indicated that sequence variants in this cluster areassociated with increased plasma lipid levels. To establish whethervariation at the APOA5 gene contributes to the transmission of CHL, weperformed linkage and linkage disequilibrium (LD) tests on a large cohortof families (n=128) with familial CHL (FCHL). The linkage data producedevidence for linkage of the APOA1/C3/A4/A5 genomic interval to FCHL (NPL= 1.7, P = 0.042). The LD studies substantiated these data. Twoindependent rare alleles, APOA5c.56G and APOC3c.386G of this gene clusterwere over-transmitted in FCHL (P = 0.004 and 0.007, respectively), andthis was associated with a reduced transmission of the most commonAPOA1/C3/A4/A5 haplotype (frequency 0.4425) to affected subjects (P =0.013). The APOA5c.56G allele was associated with increased plasmatriglyceride levels in FCHL probands, whereas the second, andindependent, APOC3c.386G allele was associated with increased plasmatriglyceride levels in FCHL pedigree founders. Thus, this allele (or anallele in LD) may mark a quantitative trait associated …
Date: September 15, 2002
Creator: Eichenbaum-Voline, Sophie; Olivier, Michael; Jones, Emma L.; Naoumova, Rossitza P.; Jones, Bethan; Gau, Brian et al.
System: The UNT Digital Library
Transuranic interfacial reaction studies on manganese oxidemineral surfaces (open access)

Transuranic interfacial reaction studies on manganese oxidemineral surfaces

Several DOE sites have been contaminated by transuranicradionuclide (TRU) discharges including neptunium and plutonium. Theirinteraction with the surrounding geological media can affect thetransport and remediation of these radionuclides in the environment.Manganese based minerals, present as minor phases in the vadose zone, canpreferentially sequester TRU over other minerals present in largerquantities. The objective of this project is to understand theinteractions between plutonium and neptunium and manganese oxyhydroxideminerals to predict potential hazards they represent to the environment,as well as to provide important scientific information for the design ofeffective remediation strategies for contaminated DOE sites.
Date: May 15, 2002
Creator: Shaughnessy, Dawn A.; Nitsche, Heino; Serne, R. Jeffrey; Shuh,David K.; Waychunas, Glenn A.; Booth, Corwin H. et al.
System: The UNT Digital Library
Apolipoprotein A5: A newly identified gene impacting plasmatriglyceride levels in humans and mice (open access)

Apolipoprotein A5: A newly identified gene impacting plasmatriglyceride levels in humans and mice

Apolipoprotein A5 (APOA5) is a newly described member of theapolipoprotein gene family whose initial discovery arose from comparativesequence analysis of the mammalian APOA1/C3/A4 gene cluster. Functionalstudies in mice indicated that alteration in the level of APOA5significantly impacted plasma triglyceride concentrations. Miceover-expressing human APOA5 displayed significantly reducedtriglycerides, while mice lacking apoA5 had a large increase in thislipid parameter. Studies in humans have also suggested an important rolefor APOA5 in determining plasma triglyceride concentrations. In theseexperiments, polymorphisms in the human gene were found to define severalcommon haplotypes that were associated with significant changes intriglyceride concentrations in multiple populations. Several separateclinical studies have provided consistent and strong support for theeffect with 24 percent of Caucasians, 35 percent of African-Americans and53 percent of Hispanics carrying APOA5 haplotypes associated withincreased plasma triglyceride levels. In summary, APOA5 represents anewly discovered gene involved in triglyceride metabolism in both humansand mice whose mechanism of action remains to be deciphered.
Date: September 15, 2002
Creator: Pennacchio, Len A. & Rubin, Edward M.
System: The UNT Digital Library
Field-scale estimation of volumetric water content using GPR groundwave techniques (open access)

Field-scale estimation of volumetric water content using GPR groundwave techniques

None
Date: May 15, 2002
Creator: Grote, K.; Hubbard, S. & Rubin, Y.
System: The UNT Digital Library
Comparison of AlxGa1-xN films grown on sapphire by MBE underN-rich and Ga-rich conditions (open access)

Comparison of AlxGa1-xN films grown on sapphire by MBE underN-rich and Ga-rich conditions

Al{sub x}Ga{sub 1-x}N layers grown under N-rich and Ga-rich conditions were investigated using transmission electron microscopy (TEM) and photoluminescence (PL). Despite a high density of threading dislocations ({approx}10{sup 10} cm{sup -2}) these layers had high PL quantum efficiencies. Both, TEM and PL studies showed significant differences between layers grown under N- and Ga-rich conditions. The results indicate that edge dislocations do contribute to nonradiative recombination in Al{sub x}Ga{sub 1-x}N layers.
Date: October 15, 2002
Creator: Jasinski, J.; Liliental-Weber, Z.; He, L.; Reshchikov, M.A. & Morkoc, H.
System: The UNT Digital Library
Anomalous creep in Sn-rich solder joints (open access)

Anomalous creep in Sn-rich solder joints

This paper discusses the creep behavior of example Sn-rich solders that have become candidates for use in Pb-free solder joints. The specific solders discussed are Sn-3.5Ag, Sn-3Ag-0.5Cu, Sn-0.7Cu and Sn-10In-3.1Ag, used in thin joints between Cu and Ni-Au metallized pads.
Date: March 15, 2002
Creator: Song, Ho Geon; Morris, John W., Jr. & Hua, Fay
System: The UNT Digital Library
A numerical study of the impacts of volatile component blending on diesel spray evaporation and combustion. (open access)

A numerical study of the impacts of volatile component blending on diesel spray evaporation and combustion.

A multiphase computational fluid dynamics (CFD) code is used to simulate the evaporation and combustion processes of a diesel spray blended with a highly volatile component. The CFD code uses an Eulerian approach to model the liquid phase of diesel fuel with components of different boiling temperatures. The approach divides the droplets into size groups and assigns different boiling temperatures for each group. The CFD code accounts for liquid droplet flow, turbulent mixing, interfacial drag and heat transfer, droplet evaporation and combustion, radiation heat transfer, and pollutant kinetics. Using the code, a parametric study was conducted to investigate the impacts of a volatile component on the spray evaporation and combustion characteristics. The results indicate that the blending of a highly volatile component can have an impact on droplet evaporation rate and that thermal radiation is significant in spray combustion due to the formation of soot.
Date: March 15, 2002
Creator: Lee, H.L.; Chang, S.L. & Petrick, M.
System: The UNT Digital Library
The Snowmass points and slopes : benchmarks for SUSY searches. (open access)

The Snowmass points and slopes : benchmarks for SUSY searches.

The ''Snowmass Points and Slopes'' (SPS) are a set of benchmark points and parameter lines in the MSSM parameter space corresponding to different scenarios in the search for Supersymmetry at present and future experiments. This set of benchmarks was agreed upon at the 2001 ''Snowmass Workshop on the Future of Particle Physics'' as a consensus based on different existing proposals.
Date: April 15, 2002
Creator: Allanach, B. C.; Battaglia, M.; Blair, G. A.; Carena, M.; De Roeck, A. & Wagner, C. E. M.
System: The UNT Digital Library
GDH pipe break transient analysis of the RBMK - 1500. (open access)

GDH pipe break transient analysis of the RBMK - 1500.

Presented in this paper is the transient analysis of a Group Distribution Header (GDH) following a guillotine break at the end of the header. The GDH is the most important component of reactor safety in case of accidents. Emergency Core Cooling System (ECCS) piping is connected to the GDH piping such that, during an accident, coolant passes from the GDH into the ECCS. The GDH that is propelled into motion after a guillotine break can impact neighboring GDH pipes or the nearest wall of the compartment. The cases of GDH impact on an adjacent GDH and its attached piping are investigated in this paper. A whipping RBMK-1500 GDH along with neighboring concrete walls and pipelines is modeled using finite elements. The finite element code NEPTUNE used in this study enables a dynamic pipe whip structural analysis that accommodates large displacements and nonlinear material characteristics. The results of the study indicate that a whipping GDH pipe would not significantly damage adjacent walls or piping and would not result in a propagation of pipe failures.
Date: May 15, 2002
Creator: Kulak , R.; Marcherta, A. & Dundulis, G.
System: The UNT Digital Library
Progress in the study of mesh refinement for particle-in-cell plasma simulations and its application to heavy ion fusion (open access)

Progress in the study of mesh refinement for particle-in-cell plasma simulations and its application to heavy ion fusion

The numerical simulation of the driving beams in a heavy ion fusion power plant is a challenging task, and, despite rapid progress in computer power, one must consider the use of the most advanced numerical techniques. One of the difficulties of these simulations resides in the disparity of scales in time and in space which must be resolved. When these disparities are in distinctive zones of the simulation region, a method which has proven to be effective in other areas (e.g. fluid dynamics simulations) is the Adaptive-Mesh-Refinement (AMR) technique. We follow in this article the progress accomplished in the last few months in the merging of the AMR technique with Particle-In-Cell (PIC) method. This includes a detailed modeling of the Lampel-Tiefenback solution for the one-dimensional diode using novel techniques to suppress undesirable numerical oscillations and an AMR patch to follow the head of the particle distribution. We also report new results concerning the modeling of ion sources using the axisymmetric WARPRZ-AMR prototype showing the utility of an AMR patch resolving the emitter vicinity and the beam edge.
Date: September 15, 2002
Creator: Vay, J. L.; Friedman, A. & Grote, D. P.
System: The UNT Digital Library
Near-Surface Engineered Environmental Barrier Integrity (open access)

Near-Surface Engineered Environmental Barrier Integrity

The INEEL Environmental Systems Research and Analysis (ESRA) program has launched a new R and D project on Near-Surface Engineered Environmental Barrier Integrity to increase knowledge and capabilities for using engineering and ecological components to improve the integrity of near-surface barriers used to confine contaminants from the public and the environment. The knowledge gained and the capabilities built will help verify the adequacy of past remedial decisions and enable improved solutions for future cleanup decisions. The research is planned to (a) improve the knowledge of degradation mechanisms (weathering, biological, geological, chemical, radiological, and catastrophic) in times shorter than service life, (b) improve modeling of barrier degradation dynamics, (c) develop sensor systems to identify degradation prior to failure, and (d) provide a better basis for developing and testing of new barrier systems to increase reliability and reduce the risk of failure. Our project combine s selected exploratory studies (benchtop and field scale), coupled effects accelerated aging testing and the meso-scale, testing of new monitoring concepts, and modeling of dynamic systems. The performance of evapo-transpiration, capillary, and grout-based barriers will be examined.
Date: May 15, 2002
Creator: Piet, S. J. & Breckenridge, R. P.
System: The UNT Digital Library
Overview of the NARSTO-NE-OPS Program. (open access)

Overview of the NARSTO-NE-OPS Program.

The NARSTO-NE-OPS (NorthEast Oxidant and Particle Study) is an investigation of the coupling of the meteorological and chemical processes that control the evolution of air pollution events. The project includes three major field programs carried out at a field site in northeast Philadelphia during the summers of 1998, 1999 and 2001. The activity brings together the research groups from 13 universities, 5 government laboratories and representatives of the electric power industry to apply the most advanced measurement techniques to understanding the physical and chemical processes contributing to air quality issues. Results have been obtained from three ground sites, two instrumented aircraft, many different instrumented balloon platforms, and several remote sensing techniques including satellites. In addition, the database used includes the ground-based measurements conducted at several surrounding state and city operated sites in Pennsylvania, New Jersey, Delaware, New York and Maryland. The results have shown the importance of developing the 3-dimensional regional scale picture of the atmosphere to understand and properly model air pollution events. It has been shown that only from such a perspective, which includes the vertical distribution and a regional context, can one hope to properly model and predict ozone and particulate pollution. A combination of photochemical and …
Date: March 15, 2002
Creator: Philbrick, C. R.; Ryan, W. F.; Clark, R. D.; Doddridge, B. G; Dickerson, R. R.; Gaffney, J. et al.
System: The UNT Digital Library
Generic aging management programs for license renewal of BWR reactor coolant systems components. (open access)

Generic aging management programs for license renewal of BWR reactor coolant systems components.

The paper reviews the existing generic aging management programs (AMPs) for the reactor coolant system (RCS) components in boiling water reactors (BWRs), including the reactor pressure vessel and internals, the reactor recirculation system, and the connected piping. These programs have been evaluated in the U.S. Nuclear Regulatory Commission (NRC) report, Generic Aging Lessons Learned (GALL), NUREG-1801, for their use in the license renewal process to manage several aging effects, including loss of material, crack initiation and growth, loss of fracture toughness, loss of preload, wall thinning, and cumulative fatigue damage. The program evaluation includes a review of ten attributes (scope of program, preventive actions, parameters monitored/inspected, detection of aging effects, monitoring and trending, acceptance criteria, corrective actions, confirmative process, administrative control, and operating experience) for their effectiveness in managing a specific aging effect in a given component(s). The generic programs are based on the ASME Section XI inservice inspection requirements; industry guidelines for inspection and evaluation of aging effects in BWR reactor vessel, internals, and recirculation piping; monitoring and control of BWR water chemistry; and operating experience as reported in the USNRC generic communications and industry reports. The review concludes that all generic AMPs are acceptable for managing aging effects …
Date: February 15, 2002
Creator: Shah, V. N. & Liu, Y. Y.
System: The UNT Digital Library
Development of Neutron Probes for Characterization of Hazardous Materials in the Sub-surface Medium (open access)

Development of Neutron Probes for Characterization of Hazardous Materials in the Sub-surface Medium

Neutron probes are being developed at the Idaho National Engineering and Environmental Laboratory (INEEL) for the detection, identification and quantification of hazardous materials in the ground. Such materials include plutonium, uranium, americium, chlorine and fluorine. Both a Neutron Gamma (NG) probe and a Prompt Fission Neutron (PFN) probe are being developed. The NG probe is used primarily for nuclide identification and quantification measurements. The PFN is used mostly for the detection and measurement of fissile material, but also for the determination of thermal neutron macroscopic absorption cross sections of the various elements comprising the ground matrix. Calibration of these probes will be carried out at the INEEL using an indoor facility that has been designed for this activity.
Date: May 15, 2002
Creator: Keegan, R.P.; McGrath, C.A. & Lopez, J.C.
System: The UNT Digital Library
Advanced intraundulator electron beam diagnostics using COTR techniques. (open access)

Advanced intraundulator electron beam diagnostics using COTR techniques.

None
Date: May 15, 2002
Creator: Lumpkin, A. H. L.; Berg, W. J. B.; Biedron, S. B.; Borland, M. B.; Chae, Y. C. C.; Dejus, R. D. et al.
System: The UNT Digital Library
Suggestions for benchmark scenarios for MSSM Higgs Boson searches at hadron colliders. (open access)

Suggestions for benchmark scenarios for MSSM Higgs Boson searches at hadron colliders.

The Higgs boson search has shifted from LEP2 to the Tevatron and will subsequently move to the LHC. Due to the different initial states, the Higgs production and decay channels relevant for Higgs boson searches were different at LEP2 to what they are at hadron colliders. They suggest new benchmark scenarios for the MSSM Higgs boson search at hadron colliders that exemplify the phenomenology of different parts of the MSSM parameter space. Besides the m{sub h}{sup max} scenario and the no-mixing scenario used in the LEP2 Higgs boson searches, they propose two new scenarios. In one the main production channel at the LHC, gg {yields} h, is suppressed. In the other, important Higgs decay channels at the Tevatron and at the LCH, h {yields} b{bar b} and h {yields} {tau}{sup +}{tau}{sup -}, are suppressed. All scenarios evade the LEP2 constraints for nearly the whole M{sub A}-tan {beta}-plane.
Date: April 15, 2002
Creator: Carena, M.; Heinemeyer, S.; Wagner, C.E.M. & Weiglein, G.
System: The UNT Digital Library
The effect of penetration factor, deposition, and environmental factors on the indoor concentration of PM2.5 sulfate, nitrate, and carbon (open access)

The effect of penetration factor, deposition, and environmental factors on the indoor concentration of PM2.5 sulfate, nitrate, and carbon

Indoor exposure to particles of outdoor origin constitutes an important exposure pathway. We conducted an intensive set of indoor particle measurements in an unoccupied house under differing operating conditions. Real-time measurements were conducted both indoors and outdoors, including PM2.5 nitrate, sulfate, and carbon. Because the time-scale of the fluctuations in outdoor particle concentrations and meteorological conditions are often similar to the time constant for building air exchange, a steady state concentration may never be reached. The time-series experimental data were used to determine the effect of changes in air exchange rate and indoor/outdoor temperature and relative humidity differences on indoor particle concentrations. A multivariate regression was performed to investigate the difference between measured indoor concentrations and results from a simple time-dependent physical model. Environmental conditions had a significant effect on indoor concentrations of all three PM2.5 species, but did not explain all of the model variation.
Date: April 15, 2002
Creator: Thatcher, T. L.; Lunden, M. M.; Sextro, R. G.; Hering, S. & Brown, N. J.
System: The UNT Digital Library
How the Grid will affect the architecture of future visualization systems (open access)

How the Grid will affect the architecture of future visualization systems

None
Date: November 15, 2002
Creator: Shalf, John & Bethel, E. Wes
System: The UNT Digital Library
Pipe whip transient analysis of the ignalina NPP. (open access)

Pipe whip transient analysis of the ignalina NPP.

None
Date: May 15, 2002
Creator: Kulak, R.; Marchertas, A.; Petri, M.; Dundulis, G. & Uspuras, E.
System: The UNT Digital Library
Designing a flexible grid enabled scientific modeling interface. (open access)

Designing a flexible grid enabled scientific modeling interface.

The Espresso Scientific Modeling Interface (Espresso) is a scientific modeling productivity tool developed from climate modelers. Espresso was designed to be an extensible interface to both scientific models and Grid resources. It also aims to be a contemporary piece of software that relies on Globus.org's Java CoG Kit for a Grid toolkit, Sun's Java 2 API and is configured using XML. This article covers the design implementation of Espresso's Grid functionality and how it interacts with existing scientific models. The authors give specific examples of how they have designed Espresso to perform climate simulations using the PSU/NCAR MM5 atmospheric model. Plans to incorporate the CCSM and FOAM climate models are also discussed.
Date: August 15, 2002
Creator: Dvorak, M.; Taylor, J. & Mickelson, S.
System: The UNT Digital Library