62 Matching Results

Results open in a new window/tab.

Applying Current Human Factors Engineering Guidance to Control Room Design (open access)

Applying Current Human Factors Engineering Guidance to Control Room Design

The Westinghouse Savannah River Company, a contractor to the Department of Energy, has compared Revisions 1 and 2 of NUREG-0700-Human System Interface Design Review Guideline, from the United States Nuclear Regulatory Commission Nuclear Regulatory Guide. The comparison has been made with respect to which guidelines remained the same, the guidelines that were reformatted or reworded, additional guidelines, and deleted guidelines. This comparison was made in preparation of revising the previously developed Human Factors Engineering Analysis Tool for automating the review, analysis, and evaluation of human system interface designs. This tool has been described at previous conferences on human factors and the merits and benefits of the tool described. The tool has been successfully applied to over eight facilities at WSRC. This paper describes the methodology and results of the comparison and the plans to enhance the already successful automation tool. The number of criteria in NUREG-0700 increased from approximately 1650 in Revision 1 to almost 2200 in Revision 2. Approximately 1600 criteria remained the same, though they were significantly reorganized; while about 100 were reworded or reformatted to clarify or expand the guidance provided. Around 600 guidelines were added and approximately 70 deleted. The majority of the changes and additions …
Date: January 31, 2005
Creator: Leo, Geary
System: The UNT Digital Library
Co-continuous Metal-Ceramic Nanocomposites (open access)

Co-continuous Metal-Ceramic Nanocomposites

A room temperature technique was developed to produce continuous metal nanowires embedded in random nanoporous ceramic skeletons. The synthesis involves preparation of uniform, nanoporous ceramic preforms, and subsequent electrochemical metal infiltration at room temperature, so to avoid materials incompatibilities frequently encountered in traditional high temperature liquid metal infiltration. Structure and preliminary evaluations of mechanical and electronic properties of copper/alumina nanocomposites are reported.
Date: January 31, 2005
Creator: Zhang, Xiao Feng; Harley, Gabriel & De Jonghe, Lutgard C.
System: The UNT Digital Library
Experimental Mathemataics: Examples, Methods andImplications (open access)

Experimental Mathemataics: Examples, Methods andImplications

Recent years have seen the flowering of ''experimental'' mathematics, namely the utilization of modern computer technology as an active tool in mathematical research. This development is not limited to a handful of researchers, nor to a handful of universities, nor is it limited to one particular field of mathematics. Instead, it involves hundreds of individuals, at many different institutions, who have turned to the remarkable new computational tools now available to assist in their research, whether it be in number theory, algebra, analysis, geometry or even topology. These tools are being used to work out specific examples, generate plots, perform various algebraic and calculus manipulations, test conjectures, and explore routes to formal proof. Using computer tools to test conjectures is by itself a major time saver for mathematicians, as it permits them to quickly rule out false notions.
Date: January 31, 2005
Creator: Bailey, David H. & Borwein, Jonathan M.
System: The UNT Digital Library
The low cost of geological assessment for underground CO2 storage: Policy and economic implications (open access)

The low cost of geological assessment for underground CO2 storage: Policy and economic implications

The costs for carbon dioxide (CO{sub 2}) capture and storage (CCS) in geologic formations is estimated to be $6-75/t CO{sub 2}. In the absence of a mandate to reduce greenhouse gas emissions or some other significant incentive for CCS deployment, this cost effectively limits CCS technology deployment to small niche markets and stymies the potential for further technological development through learning-by-doing until these disincentives for the free venting of CO{sub 2} are in place. By far, the largest current fraction of these costs is capture (including compression and dehydration), commonly estimated at $25-60/t CO{sub 2} for power plant applications followed by CO{sub 2} transport and storage, estimated at $0-15/t CO{sub 2}. Of the storage costs, only a small fraction of the cost will go to accurate geological characterization. These one-time costs are probably on the order of $0.1/t CO{sub 2} or less as these costs are spread out over the many millions of tons likely to be injected into a field over many decades. Geologic assessments include information central to capacity prediction, risk estimation for the target intervals, and development facilities engineering. Since assessment costs are roughly 2 orders of magnitude smaller than capture costs, and assessment products carry other …
Date: January 31, 2005
Creator: Friedmann, S J; Dooley, J; Held, H & Edenhofer, O
System: The UNT Digital Library
Modeling and simulation of DNA flow in a microfluidic-based pathogen detection system (open access)

Modeling and simulation of DNA flow in a microfluidic-based pathogen detection system

We present simulation results from a new computational model of DNA flow in microfluidic devices. This work is important because computational models are needed to design miniaturized biomedical devices that are becoming the state-of-the-art in many significant applications including pathogen detection as well as continuous monitoring and drug delivery. Currently advanced algorithms in design tools are non-existent but necessary to understand the complex fluid and polymer dynamics involved in biological flow at small scales. Our model is based on a fully coupled fluid-particle numerical algorithm with both stochastic and deterministic components in a bead-rod polymer representation. We have applied this work to DNA extraction configurations in a microfluidic PCR chamber used in a pathogen detection system. We demonstrate our method on the test problem of flow of a single DNA molecule in a 2D packed array microchannel. We are also investigating mechanisms for molecular ''sticking'' using short range forces.
Date: January 31, 2005
Creator: Trebotich, D & Miller, G H
System: The UNT Digital Library
Platinum nitride with fluorite structure (open access)

Platinum nitride with fluorite structure

The mechanical stability of platinum nitride has been studied using first-principles calculations. By calculating the single-crystal elastic constants, we show that platinum nitride can be stabilized in the fluorite structure, in which the nitrogen atoms occupy all the tetrahedral interstitial sites of the metal lattice. The stability is attributed to the pseudogap effect from analysis of the electronic structure.
Date: January 31, 2005
Creator: Yu, Rong & Zhang, Xiao-Feng
System: The UNT Digital Library
Space-time thermodynamics of the glass transition (open access)

Space-time thermodynamics of the glass transition

We consider the probability distribution for the fluctuations in the dynamical action of glass forming materials. We argue that the so-called glass transition is a manifestation of low action tails in these distributions where the entropy of trajectory space is sub-extensive in time. These low action tails are a consequence of dynamic heterogeneity and an indication of phase coexistence in trajectory space. The glass transition, where the system falls out of equilibrium, is then an order-disorder phenomenon in space-time occurring at a temperature T{sub g} which is a weak function of measurement time. We illustrate our perspective ideas with facilitated lattice models, and note how these ideas apply more generally.
Date: January 31, 2005
Creator: Merolle, Mauro; Garrahan, Juan P. & Chandler, David
System: The UNT Digital Library
Steady-State Diffusion of Water through Soft-Contact LensMaterials (open access)

Steady-State Diffusion of Water through Soft-Contact LensMaterials

Water transport through soft contact lenses (SCL) is important for acceptable performance on the human eye. Chemical-potential gradient-driven diffusion rates of water through soft-contact-lens materials are measured with an evaporation-cell technique. Water is evaporated from the bottom surface of a lens membrane by impinging air at controlled flow rate and humidity. The resulting weight loss of a water reservoir covering the top surface of the contact-lens material is recorded as a function of time. New results are reported for a conventional hydrogel material (SofLens{trademark} One Day, hilafilcon A, water content at saturation W{sub 10} = 70 weight %) and a silicone hydrogel material (PureVision{trademark}, balafilcon A, W{sub 10} = 36 %), with and without surface oxygen plasma treatment. Also, previously reported data for a conventional HEMA-SCL (W{sub 10} = 38 %) hydrogel are reexamined and compared with those for SofLens{trademark} One Day and PureVision{trademark} hydrogels. Measured steady-state water fluxes are largest for SofLens{trademark} One Day, followed by PureVision{trademark} and HEMA. In some cases, the measured steady-state water fluxes increase with rising relative air humidity. This increase, due to an apparent mass-transfer resistance at the surface (trapping skinning), is associated with formation of a glassy skin at the air/membrane interface when …
Date: January 31, 2005
Creator: Fornasiero, Francesco; Krull, Florian; Radke, Clayton J. & Prausnitz, JohnM.
System: The UNT Digital Library
Conference Paper/Proceedings White Paper Conference Results of March 3, 2005 Workshop in Irvine, CA (open access)

Conference Paper/Proceedings White Paper Conference Results of March 3, 2005 Workshop in Irvine, CA

A one-day workshop sponsored by UC Irvine's Center for Urban Infrastructure, bringing together 20 state departments of transportation and environmental quality to discuss national coordination on alternative fuels.
Date: March 31, 2005
Creator: Redman, Deborah Hart & Catz, Sarah L.
System: The UNT Digital Library
Electrons and gas versus high brightness ion beams (open access)

Electrons and gas versus high brightness ion beams

None
Date: March 31, 2005
Creator: Molvik, A. W.; Cohen, R. H.; Bieniosek, F.; Friedman, A.; Kireeff Covo, M.; Lund, S. M. et al.
System: The UNT Digital Library
Evolving Dark Energy with w =/ -1 (open access)

Evolving Dark Energy with w =/ -1

Theories of evolving quintessence are constructed that generically lead to deviations from the w = -1 prediction of non-evolving dark energy. The small mass scale that governs evolution, m_\phi \approx 10^-33 eV, is radiatively stable, and the"Why Now?'' problem is solved. These results rest crucially on seesaw cosmology: in broad outline, fundamental physics and cosmology can be understood from only two mass scales, the weak scale, v, and the Planck scale, M. Requiring a scale of dark energy \rho_DE^1/4 governed by v^2/M, and a radiatively stable evolution rate m_\phi given by v^4/M^3, leads to a distinctive form for the equation of state w(z) that follows from a cosine quintessence potential. An explicit hidden axion model is constructed. Dark energy resides in the potential of the axion field which is generated by a new QCD-like force that gets strong at the scale \Lambda \approx v^2/M \approx \rho_DE^1/4. The evolution rate is given by a second seesaw that leads to the axion mass, m_\phi \approx \Lambda^2/f, with f \approx M.
Date: March 31, 2005
Creator: Hall, Lawrence J.; Nomura, Yasunori & Oliver, Steven J.
System: The UNT Digital Library
The Impact of Glucuronidation on the Bioactivation and DNA Adduction of the Cooked-Food Carcinogen 2-Amino-1-methyl-6-phenylimidazo[4,5-b] pyridine in vivo (open access)

The Impact of Glucuronidation on the Bioactivation and DNA Adduction of the Cooked-Food Carcinogen 2-Amino-1-methyl-6-phenylimidazo[4,5-b] pyridine in vivo

UDP-glucuronosyltransferases (UGTs) catalyze the glucuronidation of many different chemicals. Glucuronidation is especially important for detoxifying reactive intermediates from metabolic reactions, which otherwise can be biotransformed into highly reactive cytotoxic or carcinogenic species. Detoxification of certain food-borne carcinogenic heterocyclic amines (HAs) is highly dependent on UGT1A-mediated glucuronidation. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), the most mass abundant carcinogenic HA found in well-done cooked meat, is extensively glucuronidated by UGT1A proteins. In humans, CYP1A2 catalyzed N-hydroxylation and subsequent UGT1A-mediated glucuronidation is a dominant pathway in the metabolism of PhIP. Therefore, changes in glucuronidation rates could significantly alter PhIP metabolism. To determine the importance of UGT1A-mediated glucuronidation in the biotransformation of PhIP, UGT1A proficient Wistar and UGT1A deficient Gunn rats were exposed to a single 100 {micro}g/kg oral dose of [{sup 14}C]-PhIP. Urine was collected over 24 h and the PhIP urinary metabolite profiles were compared between the two strains. After the 24 h exposure, livers and colon were removed and analyzed for DNA adduct formation by accelerator mass spectrometry. Wistar rats produced several PhIP and N-hydroxy-PhIP glucuronides that accounted for {approx}25% of the total amount of recovered urinary metabolites. In the Gunn rats, PhIP and N-hydroxy-PhIP glucuronides were reduced by 68-92%, compared to the Wistar rats, …
Date: March 31, 2005
Creator: Malfatti, M A; Ubick, E A & Felton, J S
System: The UNT Digital Library
Magnetic Properties of Radiation Damage in Pu and Pu Alloys (open access)

Magnetic Properties of Radiation Damage in Pu and Pu Alloys

Among the many exceptional properties of Pu is its apparent lack of either local moments or cooperative magnetism. Lashley et al., have recently noted that little experimental evidence for the existence of local moments or collective magnetism has been found in over 50 years. Nevertheless the search for local moments in Pu and Pu-alloys continues, why? Plutonium's physical properties: resistance, magnetic susceptibility, and heat capacity, all support a system with an enhanced electron density of states. Pu sits on the edge of both magnetism and superconductivity and possesses one of the highest elemental Pauli susceptibilities, consistent with a highly correlated electron system. The low-density {delta}-Pu has eluded full first principles description and is both a challenge and an area of active investigation for theorists. The complex changes associated with the transition between the light and heavy actinides happen within the phase diagram of Pu, thus making Pu an intriguing and challenging solid-state system for continuing experimental and theoretical investigation. Recently, Griveau et al., observed the variations in the resistance and superconducting properties of Am metal as a function of pressure to 27GPa and T>0.4K. They postulate that the interesting features in the superconducting critical temperature, T{sub c}, vs. pressure, indicate …
Date: March 31, 2005
Creator: McCall, S.; Fluss, M. J.; Chung, B.; Chapline, G.; McElfresh, M.; Jackson, D. et al.
System: The UNT Digital Library
Next Generation - Monitored Natural Attenuation And Enhanced Attenuation - Chlorinated Solvents (open access)

Next Generation - Monitored Natural Attenuation And Enhanced Attenuation - Chlorinated Solvents

Monitored Natural Attenuation (MNA) is a necessary part of the remedial action at most chlorinated solvent sites. As a result, site owners, stakeholders, and regulators are identifying and responding to MNAs technical challenges. For example, many contaminated plumes are not in anaerobic settings, making it unlikely the predominant mechanism embodied in existing protocols and guidance documents, reductive dechlorination, will be viable. This is the case for many of the chlorinated solvent sites at Department of Energy (DOE) facilities. The DOE is conducting a project to explore the possibility of other mechanisms contributing to the attenuation of chlorination solvents in the environment. The project is exploring three key areas: mass balance as a way to evaluate the significance of the different processes occurring at a site, sustainable enhancements as a way to increase the attenuation capacity of a site so that it is sustained allowing remediation goals to be met, and characterization and performance monitoring methods that will support the first two areas in a manner that will support transition to legacy management.
Date: March 31, 2005
Creator: KAREN, VANGELAS
System: The UNT Digital Library
Proposal for a High Energy Nuclear Database (open access)

Proposal for a High Energy Nuclear Database

We propose to develop a high-energy heavy-ion experimental database and make it accessible to the scientific community through an on-line interface. This database will be searchable and cross-indexed with relevant publications, including published detector descriptions. Since this database will be a community resource, it requires the high-energy nuclear physics community's financial and manpower support. This database should eventually contain all published data from Bevalac and AGS to RHIC to CERN-LHC energies, proton-proton to nucleus-nucleus collisions as well as other relevant systems, and all measured observables. Such a database would have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models to a broad range of old and new experiments. Furthermore, there is a growing need for compilations of high-energy nuclear data for applications including stockpile stewardship, technology development for inertial confinement fusion and target and source development for upcoming facilities such as the Next Linear Collider. To enhance the utility of this database, we propose periodically performing evaluations of the data and summarizing the results in topical reviews.
Date: March 31, 2005
Creator: Brown, David A. & Vogt, Ramona
System: The UNT Digital Library
Proposal for a High Energy Nuclear Database (open access)

Proposal for a High Energy Nuclear Database

The authors propose to develop a high-energy heavy-ion experimental database and make it accessible to the scientific community through an on-line interface. This database will be searchable and cross-indexed with relevant publications, including published detector descriptions. Since this database will be a community resource, it requires the high-energy nuclear physics community's financial and manpower support. This database should eventually contain all published data from Bevalac, AGS and SPS to RHIC and CERN-LHC energies, proton-proton to nucleus-nucleus collisions as well as other relevant systems, and all measured observables. Such a database would have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models to a broad range of old and new experiments. Furthermore, there is a growing need for compilations of high-energy nuclear data for applications including stockpile stewardship, technology development for inertial confinement fusion and target and source development for upcoming facilities such as the Next Linear Collider. To enhance the utility of this database, they propose periodically performing evaluations of the data and summarizing the results in topical reviews.
Date: March 31, 2005
Creator: Brown, D. A. & Vogt, R.
System: The UNT Digital Library
Surface Structures of Cubo-octahedral Pt-Mo Catalyst Nanoparticles from Monte Carlo Simulations (open access)

Surface Structures of Cubo-octahedral Pt-Mo Catalyst Nanoparticles from Monte Carlo Simulations

The surface structures of cubo-octahedral Pt-Mo nanoparticles have been investigated using the Monte Carlo method and modified embedded atom method potentials that we developed for Pt-Mo alloys. The cubo-octahedral Pt-Mo nanoparticles are constructed with disordered fcc configurations, with sizes from 2.5 to 5.0 nm, and with Pt concentrations from 60 to 90 at. percent. The equilibrium Pt-Mo nanoparticle configurations were generated through Monte Carlo simulations allowing both atomic displacements and element exchanges at 600 K. We predict that the Pt atoms weakly segregate to the surfaces of such nanoparticles. The Pt concentrations in the surface are calculated to be 5 to 14 at. percent higher than the Pt concentrations of the nanoparticles. Moreover, the Pt atoms preferentially segregate to the facet sites of the surface, while the Pt and Mo atoms tend to alternate along the edges and vertices of these nanoparticles. We found that decreasing the size or increasing the Pt concentration leads to higher Pt concentrations but fewer Pt-Mo pairs in the Pt-Mo nanoparticle surfaces.
Date: March 31, 2005
Creator: Wang, Guofeng; Van Hove, M.A.; Ross, P.N. & Baskes, M.I.
System: The UNT Digital Library
Trends in Environmental Analysis (open access)

Trends in Environmental Analysis

This article discusses developments in environmental analytical chemistry that occurred in the years of 2003 and 2004. References were found by searching the ''Science Citation Index and Current Contents''. As in our review of two years ago (A1), techniques are highlighted that represent current trends and state-of-the-art technologies in the sampling, extraction, separation, and detection of trace concentrations, low-part-per-billion and less, of organic, inorganic, and organometallic contaminants in environmental samples. New analytes of interest are also reviewed, the detections of which are made possible by recently developed analytical instruments and methods.
Date: March 31, 2005
Creator: Koester, C. J. & Moulik, A.
System: The UNT Digital Library
Accounting Procedures for Foreign-owned Nuclear Material Located Temporarily in the Russian Federation (open access)

Accounting Procedures for Foreign-owned Nuclear Material Located Temporarily in the Russian Federation

None
Date: May 31, 2005
Creator: Pitel, V. A.; Kasumova, L. A. & Babcock, R. A.
System: The UNT Digital Library
Bank Upgrade for Sspx at Llnl (open access)

Bank Upgrade for Sspx at Llnl

A new 5kV, 1.5MJ modular capacitor bank has been designed for the Sustained Spheromak Physics Experiment (SSPX) at LLNL. The new bank consists of thirty 4mF capacitors that are independently controlled by light-triggered thyristors. By closing all switches simultaneously, the bank will provide a mega-ampere discharge. The new bank will also allow additional capabilities to SSPX, including higher peak gun current, longer current pulses, and multi-pulse plasma buildup. Experiment results for a single stage prototype will be presented, deliver a single large current spike, or, switches can be triggered in sequence to deliver a longer lower current pulse. Multiple pulses can be created by triggering sections of the modular bank in intervals.
Date: May 31, 2005
Creator: Marchiano, M. M.; Cook, E. G.; Geer, R. W.; Kemptner, R. O.; McLean, H. S.; Martovetsky, N. N. et al.
System: The UNT Digital Library
Class B0631+519: Last of the Class Lenses (open access)

Class B0631+519: Last of the Class Lenses

We report the discovery of the new gravitational lens system CLASS B0631+519. Imaging with the VLA, MERLIN and the VLBA reveals a doubly-imaged flat-spectrum radio core, a doubly-imaged steep-spectrum radio lobe and possible quadruply-imaged emission from a second lobe. The maximum separation between the lensed images is 1.16 arcsec. High resolution mapping with the VLBA at 5 GHz resolves the most magnified image of the radio core into a number of sub-components spread across approximately 20 mas. No emission from the lensing galaxy or an odd image is detected down to 0.31 mJy (5{sigma}) at 8.4 GHz. Optical and near-infrared imaging with the ACS and NICMOS cameras on the HST show that there are two galaxies along the line of sight to the lensed source, as previously discovered by optical spectroscopy. We find that the foreground galaxy at z=0.0896 is a small irregular, and that the other, at z=0.6196 is a massive elliptical which appears to contribute the majority of the lensing effect. The host galaxy of the lensed source is detected in the HST near-infrared imaging as a set of arcs, which form a nearly complete Einstein ring. Mass modeling using non-parametric techniques can reproduce the near-infrared observations and …
Date: May 31, 2005
Creator: York, Tom; Jackson, N.; Browne, I. W. A.; Koopmans, L. V. E.; McKean, J. P.; Norbury, M. A. et al.
System: The UNT Digital Library
The Last of the Finite Loop Amplitudes in QCD (open access)

The Last of the Finite Loop Amplitudes in QCD

We use on-shell recursion relations to determine the one-loop QCD scattering amplitudes with a massless external quark pair and an arbitrary number (n - 2) of positive-helicity gluons. These amplitudes are the last of the unknown infrared- and ultraviolet-finite loop amplitudes of QCD. The recursion relations are similar to ones applied at tree level, but contain new non-trivial features corresponding to poles present for complex momentum arguments but absent for real momenta. We present the relations and the compact solutions to them, valid for all n. We also present compact forms for the previously-computed one-loop n-gluon amplitudes with a single negative helicity and the rest positive helicity.
Date: May 31, 2005
Creator: Bern, Zvi; Dixon, Lance J. & Kosower, David A.
System: The UNT Digital Library
Many-body effects in the 4f x-ray photoelectron spectroscopy of the U5+ and U4+ free ions (open access)

Many-body effects in the 4f x-ray photoelectron spectroscopy of the U5+ and U4+ free ions

This article discusses many-body effects in the 4f x-ray photoelectron spectroscopy of the U5+ and U4+ free ions.
Date: May 31, 2005
Creator: Ilton, Eugene S. & Bagus, Paul S.
System: The UNT Digital Library
Optimum model-E-GAMS for Distributed Energy System by Using GAMSMethod (open access)

Optimum model-E-GAMS for Distributed Energy System by Using GAMSMethod

DER-CAM Developed by the Lawrence Berkeley National Laboratory (LBNL), is an optimization tool for DER technology selection. However it can not be simply applied to the Japanese case because of the different climate and the utility tariff. This research aims to develop an optimization tool for distributed energy for Japanese buildings using GAMS, a high-level modeling system for mathematical programming and optimization. This paper describes how we apply and demonstrate the tool to the energy center at Kitakyushu Research city, where has installed a fuel cell and a gas engine. An analysis has also been conducted to see how the utility tarriff and the equipment efficiency can affect the operation of the DER system.
Date: May 31, 2005
Creator: Yang, Yongwen; Gao, Weijun; Ruan, Yingjun; Zhou, Nan; Xuan, Ji & Marnay, Chris
System: The UNT Digital Library