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Fiscal Year 2003
15
OIT Best Practices
15
Fiscal Year 2002
14
Distributed Energy & Electric Reliability Fact Sheets
7
Field Demonstration of a Membrane Process to Separate Nitrogen From Natural Gas Progress Report
7
Clean Cities alternative fuel information series
6
Small Wind Electric Systems Consumers' Guides
6
ARM Facilities Newsletter
5
Alternative Fuel News
5
Analysis of Devonian Black Shales in Kentucky for Potential Carbon Dioxide Sequestration and Enhanced Natural Gas Production Quarterly Report
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Materials Science at the Extremes of Pressure and Strain Rate
Solid state experiments at very high pressures and strain rates are possible on high power laser facilities, albeit over brief intervals of time and spatial small scales. A new shockless drive has been developed on the Omega laser. VISAR measurements establish the high strain rates, 10{sup 7}-10{sup 8} s{sup -1}. Solid-state strength is inferred using the Rayleigh-Taylor instability as a ''diagnostic''. Temperature and compression in polycrystalline samples can be deduced from EXAFS measurements. Lattice response can be inferred from time-resolved x-ray diffraction. Deformation mechanisms can be identified by examining recovered samples. We will briefly review this new area of laser-based materials science research, then present a path forward for carrying these solid-state experiments to much higher pressures, P >> 1 Mbar, on the NIF laser facility.
Date:
August 20, 2003
Creator:
Remington, B. A.; Cavallo, R. M.; Edwards, M. J.; Lasinski, B. F.; Lorenz, K. T.; Lorenzana, H. E. et al.
Object Type:
Article
System:
The UNT Digital Library
Multi-fluid code simulations including anomalous non-diffusive transport of plasma and impurities in the tokamak SOL
Fast intermittent transport has been observed in the scrape-off layer (SOL) of major tokamaks including Alcator C-Mod, DIII-D, and NSTX. This kind of transport is not diffusive but rather convective. It strongly increases plasma flux to the chamber walls and enhances the recycling of neutral particles in the main chamber. We discuss anomalous cross-field convection (ACFC) model for impurity and main plasma ions and its relation to intermittent transport events, i.e. plasma density blobs and holes in the SOL. Along with plasma diffusivity coefficients, our transport model introduces time-independent anomalous cross-field convective velocity. In the discharge modelling, diffusivity coefficients and ACFC velocity profiles are adjusted to match a set of representative experimental data. We use this model in the edge plasma physics code UEDGE to simulate the multi-fluid two-dimensional transport for these three tokamaks. We present simulation results suggesting the dominance of anomalous convection in the far SOL transport. These results are consistent with the hypothesis that the chamber wall is an important source of impurities and that different impurity charge states have different directions of anomalous convective velocity.
Date:
November 25, 2003
Creator:
Pigarov, A. Yu; West, W. P.; Soukhanovskii, V.; Rognlien, T. D.; Maingi, R.; Lipschultz, B. et al.
Object Type:
Article
System:
The UNT Digital Library
Influence of Clastic Dikes on Vertical Migration of Contaminants in the Vadose Zone at Hanford
The purpose of this study was to examine the hypothesis that clastic dikes could form a preferential flow path through the vadose zone to the water table at the Hanford Site. Clastic dikes are subvertical structures that form within sedimentary sequences after deposition, and cut across the original sedimentary layers. They are common throughout the Hanford Site, often occurring in organized polygonal networks. In the initial phase of the project, we analyzed the large-scale geometry of the clastic dikes and developed an algorithm for simulating their spatial distribution. This result will be useful in providing maps of the potential distribution of clastic dikes in areas where they are not exposed at the surface (e.g., where covered by windblown sand or by construction of facilities like tank farms at the surface). In addition to the study of the large scale distribution of the dikes, a major focus of the project was on field, laboratory, and modeling studies of the hydrogeologic al properties of the clastic dikes and the effect that they have on transport of water through the vadose zone. These studies were performed at two field locations at the Hanford Site. We performed an extensive series of field and laboratory …
Date:
March 14, 2003
Creator:
Murray, Christopher J.; Ward, Anderson L. & Wilson, John L.
Object Type:
Report
System:
The UNT Digital Library
Reconnaissance of Field Sites for the Study of Chemical Weathering on the Guayana Shield, South America
Despite the fact that chemical weathering of silicate rocks plays an important role in the draw-down of CO{sub 2} over geologic time scales (Berner and Berner, 1996), the overall controls on the rate of chemical weathering are still not completely understood. Lacking a mechanistic understanding of these controls, it remains difficult to evaluate a hypothesis such as that presented by Raymo and Ruddiman (1992), who suggested that enhanced weathering and CO{sub 2} draw-down resulting from the uplift of the Himalayas contributed to global cooling during the Cenozoic. At an even more fundamental level, the three to four order of magnitude discrepancy between laboratory and field weathering rates is still unresolved (White et al., 1996). There is as yet no comprehensive, mechanistic model for silicate chemical weathering that considers the coupled effects of precipitation, vadose zone flow, and chemical reactions. The absence of robust process models for silicate weathering and the failure to resolve some of these important questions may in fact be related-the controls on the overall rates of weathering cannot be understood without considering the weathering environment as one in which multiple, time-dependent chemical and physical processes are coupled (Malmstrom, 2000). Once chemical weathering is understood at a mechanistic …
Date:
February 1, 2003
Creator:
Steefell, C. I.; Viani, B. E.; Ramirez, A. & Lee, K.
Object Type:
Report
System:
The UNT Digital Library
Laser Peening--Strengthening Metals to Improve Fatigue Lifetime and Retard Stress-Induced Corrosion Cracking in Gears, Bolts and Cutter
Laser peening is an emerging modern process that impresses a compressive stress into the surfaces of metals. Treatment can reduce the rate of fatigue cracking and stress-corrosion-cracking in metals (such as gears, bolts and cutters) needed for tunnel boring and other construction & mining applications. Laser peening could also be used to form metals or alloys into a precise shape without yielding and leaving both sulfates in a crack resistant compressive state.
Date:
August 20, 2003
Creator:
Hackel, L. A. & Chen, H. L.
Object Type:
Report
System:
The UNT Digital Library
Linear Model for Non Isosceles Absorbers.
Previous analyses have assumed that wedge absorbers are triangularly shaped with equal angles for the two faces. In this case, to linear order, the energy loss depends only on the position in the direction of the face tilt, and is independent of the incoming angle. One can instead construct an absorber with entrance and exit faces facing rather general directions. In this case, the energy loss can depend on both the position and the angle of the particle in question. This paper demonstrates that and computes the effect to linear order.
Date:
May 12, 2003
Creator:
Berg, J. S.
Object Type:
Article
System:
The UNT Digital Library
Effect of Ethanol and Methyl-tert-Butyl Ether on Monoaromatic Hydrocarbon Biodegradation: Response Variability for Different Aquifer Materials Under Various Electron-Accepting Conditions
Aquifer microcosms were used to determine how ethanol and methyl-tert-butyl ether (MtBE) affect monoaromatic hydrocarbon degradation under different electron-accepting conditions commonly found in contaminated sites experiencing natural attenuation. Response variability was investigated by using aquifer material from four sites with different exposure history. The lag phase prior to BTEX (benzene, toluene, ethylbenzene, and xylenes) and ethanol degradation was typically shorter in microcosms with previously contaminated aquifer material, although previous exposure did not always result in high degradation activity. Toluene was degraded in all aquifer materials and generally under a broader range of electron-accepting conditions compared to benzene, which was degraded only under aerobic conditions. MtBE was not degraded within 100 days under any condition, and it did not affect BTEX or ethanol degradation patterns. Ethanol was often degraded before BTEX compounds, and had a variable effect on BTEX degradation as a function of electron-accepting conditions and aquifer material source. An occasional enhancement of toluene degradation by ethanol occurred in denitrifying microcosms with unlimited nitrate; this may be attributable to the fortuitous growth of toluene-degrading bacteria during ethanol degradation. Nevertheless, experiments with flow-through aquifer columns showed that this beneficial effect could be eclipsed by an ethanol-driven depletion of electron acceptors, which …
Date:
October 6, 2003
Creator:
Ruiz-Aguilar, G L; Fernandez-Sanchez, J M; Kane, S R; Kim, D & Alvarez, P J
Object Type:
Article
System:
The UNT Digital Library
Geophysical Models for Nuclear Explosion Monitoring
Geophysical models are increasingly recognized as an important component of regional calibrations for seismic monitoring. The models can be used to predict geophysical measurements, such as body wave travel times, and can be derived from direct regional studies or even by geophysical analogy. While empirical measurements of these geophysical parameters might be preferred, in aseismic regions or regions without seismic stations, this data might not exist. In these cases, models represent a 'best guess' of the seismic properties in a region, which improves on global models such as the PREM (Preliminary Reference Earth Model) or the IASPEI (International Association of Seismology and Physics of the Earth's Interior) models. The model-based predictions can also serve as a useful background for the empirical measurements by removing trends in the data. To this end, Lawrence Livermore National Laboratory (LLNL) has developed the WENA model for Western Eurasia and North Africa. This model is constructed using a regionalization of several dozen lithospheric (crust and uppermost mantle) models, combined with the Laske sediment model and 3SMAC upper mantle. We have evaluated this model using a number of data sets, including travel times, surface waves, receiver functions, and waveform analysis. Similarly, Los Alamos National Laboratory (LANL) …
Date:
July 16, 2003
Creator:
Pasyanos, M E; Walter, W R & Flanagan, M
Object Type:
Article
System:
The UNT Digital Library
$1.6 Million in Savings Identified in Anchor Assessment: Plant-Wide Assessment Summary--Glass (Fact Sheet)
Summary of Anchor Glass' plant-wide assessment to identify energy and cost saving opportunities at the corporation's facilities in Warner Robins, GA and Jacksonville, FL.
Date:
August 1, 2003
Creator:
unknown
Object Type:
Text
System:
The UNT Digital Library
Feasibility Study of Passive Aerosol Sampler for Bio-Agent Detection
We propose to establish the feasibility of a passive aerosol sampler for bio-agent collection through laboratory experiments and theoretical analysis. The passive sampler, unlike the typical active sampler, does not require pumps and complex fixtures, and thereby allows for large-scale field monitoring not possible with current active samplers. We plan to conduct experiments using model (both biological and non-biological) aerosols generated in an instrumented test chamber and compare the particles collected on various passive samplers to conventional filter samplers, commercial aerosol measuring instruments and to conventional surface swipes. Theoretical analysis will be used to design prototype passive samplers and to compare experimental results with theory. A successful feasibility study will be used to seek outside funding for applications that will greatly enhance current LLNL programs such as NARAC's atmospheric dispersal modeling, NAI's programs in bioagent monitoring in public locations and fixed sampling stations, and EPD's environmental monitoring and decontamination research. In addition, the feasibility study will position us favorably for responding to new calls for proposals by NIH and EPA for large scale environmental studies.
Date:
March 5, 2003
Creator:
Keating, G. & Bergman, W.
Object Type:
Report
System:
The UNT Digital Library
Analytic ICF Hohlraum Energetics
We apply recent analytic solutions to the radiation diffusion equation to problems of interest for ICF hohlraums. The solutions provide quantitative values for absorbed energy which are of use for generating a desired radiation temperature vs. time within the hohlraum. Comparison of supersonic and subsonic solutions (heat front velocity faster or slower, respectively, than the speed of sound in the x-ray heated material) suggests that there may be some advantage in using high Z metallic foams as hohlraum wall material to reduce hydrodynamic losses, and hence, net absorbed energy by the walls. Analytic and numerical calculations suggest that the loss per unit area might be reduced {approx} 20% through use of foam hohlraum walls. Reduced hydrodynamic motion of the wall material may also reduce symmetry swings, as found for heavy ion targets.
Date:
August 27, 2003
Creator:
Rosen, M D & Hammer, J
Object Type:
Article
System:
The UNT Digital Library
A Source-to-Source Architecture for User-Defined Optimizations
The performance of object-oriented applications often suffers from the inefficient use of high-level abstractions provided by underlying libraries. Since these library abstractions are user-defined and not part of the programming language itself only limited information on their high-level semantics can be leveraged through program analysis by the compiler and thus most often no appropriate high-level optimizations are performed. In this paper we outline an approach based on source-to-source transformation to allow users to define optimizations which are not performed by the compiler they use. These techniques are intended to be as easy and intuitive as possible for potential users; i.e. for designers of object-oriented libraries, people most often only with basic compiler expertise.
Date:
February 6, 2003
Creator:
Schordan, M & Quinlan, D
Object Type:
Article
System:
The UNT Digital Library
Shock-Dispersed-Fuel Charges: Combustion in Chambers and Tunnels
None
Date:
April 23, 2003
Creator:
Neuwald, P; Reichenbach, H & Kuhl, A L
Object Type:
Article
System:
The UNT Digital Library
Astronomy Applications of Adaptive Optics at Lawrence Livermore National Laboratory
Astronomical applications of adaptive optics at Lawrence Livermore National Laboratory (LLNL) has a history that extends from 1984. The program started with the Lick Observatory Adaptive Optics system and has progressed through the years to lever-larger telescopes: Keck, and now the proposed CELT (California Extremely Large Telescope) 30m telescope. LLNL AO continues to be at the forefront of AO development and science.
Date:
April 23, 2003
Creator:
Bauman, B J & Gavel, D T
Object Type:
Article
System:
The UNT Digital Library
Physical evidence for dark energy
The authors present measurements of the angular cross-correlation between luminous red galaxies from the Sloan Digital Sky Survey and the cosmic microwave background temperature maps from the Wilkinson Microwave Anisotropy Probe. They find a statistically significant achromatic positive correlation between these two data sets, which is consistent with the expected signal from the late Integrated Sachs-Wolfe (ISW) effect. they do not detect any anti-correlation on small angular scales as would be produced from a large Sunyaev-Zel'dovich (SZ) effect, although they do see evidence for some SZ effect for their highest redshift samples. Assuming a flat universe, their preliminary detection of the ISW effect provides independent physical evidence for the existence of dark energy.
Date:
July 1, 2003
Creator:
Scranton, Ryan; Connolly, Andrew J.; Nichol, Robert C.; Stebbins, Albert; Szapudi, Istvan; Eisenstein, Daniel J. et al.
Object Type:
Article
System:
The UNT Digital Library
ACTION AND PHASE ANALYSIS TO DETERMINE SEXTUPOLE ERRORS IN RHIC AND THE SPS.
Success in the application of the action and phase analysis to find linear errors at RHIC Interaction Regions [1] has encouraged the creation of a technique based on the action and phase analysis to find non linear errors. In this paper we show the first attempt to measure the sextupole components at RHIC interaction regions using the action and phase method. Experiments done by intentionally activating sextupoles in RHIC and in SPS [2] will also be analyzed with this method. First results have given values for the sextupole errors that at least have the same order of magnitude as the values found by an alternate technique during the RHIC 2001 run [3].
Date:
May 12, 2003
Creator:
Cardona, J.; Peggs, S.; Satogata, T. & Tomas, R.
Object Type:
Article
System:
The UNT Digital Library
Thermo-Gas-Dynamic Model of Afterburning in Explosions
A theoretical model of afterburning in explosions created by turbulent mixing of the detonation products from fuel-rich charges with air is described. It contains three key elements: (i) a thermodynamic-equilibrium description of the fluids (fuel, air, and products), (ii) a multi-component gas-dynamic treatment of the flow field, and (iii) a sub-grid model of molecular processes of mixing, combustion and equilibration.
Date:
July 27, 2003
Creator:
Kuhl, A L; Ferguson, R E & Bell, J B
Object Type:
Article
System:
The UNT Digital Library
Entangled States, Holography and Quantum Surfaces
Starting with an elementary discussion of quantum holography, we show that entangled quantum states of qubits provide a ''local'' representation of the global geometry and topology of quantum Riemann surfaces. This representation may play an important role in both mathematics and physics. Indeed, the simplest way to represent the fundamental objects in a ''theory of everything'' may be as muti-qubit entangled states.
Date:
August 13, 2003
Creator:
Chapline, G F
Object Type:
Report
System:
The UNT Digital Library
Tilted Thick-Disk Accretion onto a Kerr Black Hole
We present the first results from fully general relativistic numerical studies of thick-disk accretion onto a rapidly-rotating (Kerr) black hole with a spin axis that is tilted (not aligned) with the angular momentum vector of the disk. We initialize the problem with the solution for an aligned, constant angular momentum, accreting thick disk around a black hole with spin a/M = J/M{sup 2} = +0.9 (prograde disk). The black hole is then instantaneously tilted, through a change in the metric, by an angle {beta}{sub 0}. In this Letter we report results with {beta}{sub 0} = 0, 15, and 30{sup o}. The disk is allowed to respond to the Lense-Thirring precession of the tilted black hole. We find that the disk settles into a quasi-static, twisted, warped configuration with Lense-Thirring precession dominating out to a radius analogous to the Bardeen-Petterson transition in tilted Keplerian disks.
Date:
December 12, 2003
Creator:
Fragile, P C & Anninos, P
Object Type:
Article
System:
The UNT Digital Library
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
Delamination Failure Investigation for Out-Of-Plane Loading in Laminates
In contrast to failure approaches at the lamina level or the micromechanics level the present work concerns failure characterization at the laminate level. Specifically, attention is given to the ultimate failure characterization for quasi-isotropic laminates. This is in further contrast to the commonly used approaches for initial damage or progressive damage. It is shown that the analytical failure forms decompose into two modes, one for out of plane, delamination type failure and one for in plane, fiber controlled type failure. The work here is mainly given over to the delamination mode of failure. Experimental results are presented for laminates in this mode of failure. These results are then integrated with the analytical forms to give a simple criterion for delamination failure.
Date:
March 26, 2003
Creator:
Christensen, R M & DeTeresa, S J
Object Type:
Article
System:
The UNT Digital Library
Microstructure of Surface Layers in Cu(In,Ga)Se2 Thin Films
In most Cu(In,Ga)Se2 thin films used for solar cells, there usually exist interfaces lying about 0.1 to 0.2 m below the surfaces. We report on a convergent-beam electron diffraction and energy-dispersive X-ray spectroscopy study of the microstructure and chemical composition of the surface region in Cu(In,Ga)Se2 thin films. We find that the surface region and the bulk are structurally similar, with no ordered defect chalcopyrite structure observed. However, their composition is slightly different, indicating that they can have different point-defect physics. Our results suggest that the subinterfaces and the bulk absorber may form homojunctions.
Date:
May 1, 2003
Creator:
Yan, Y.; Jones, K. M.; AbuShama, J.; Young, M.; Asher, S.; Al-Jassim, M. M. et al.
Object Type:
Article
System:
The UNT Digital Library
ELECTRON CLOUD AND PRESSURE RISE SIMULATIONS FOR RHIC.
Beam induced electron multipacting may be among the main reasons for the vacuum pressure rise when circulating high intensity ion and proton beams in RHIC. Latest simulation results are benchmarked with recent experimental observations for RHIC, and compared to other general computer codes. The influence of the electron multipacting to the vacuum properties is also discussed.
Date:
May 12, 2003
Creator:
IRISO-ARIZ,U. BLASKIEWICZ,M. DREES,A. FISCHER,W. PEGGS,S. TRBOJEVIC,D.
Object Type:
Article
System:
The UNT Digital Library
ADVANCEMENT OF THE RHIC BEAM ABORT KICKER SYSTEM.
As one of the most critical system for RHIC operation, the beam abort kicker system has to be highly available, reliable, and stable for the entire operating range. Along with the RHIC commission and operation, consistent efforts have been spend to cope with immediate issues as well as inherited design issues. Major design changes have been implemented to achieve the higher operating voltage, longer high voltage hold-off time, fast retriggering and redundant triggering, and improved system protection, etc. Recent system test has demonstrated for the first time that both blue ring and yellow ring beam abort systems have achieved more than 24 hours hold off time at desired operating voltage. In this paper, we report break down, thyratron reverse arcing, and to build a fast re-trigger system to reduce beam spreading in event of premature discharge.
Date:
May 12, 2003
Creator:
ZHANG,W. AHRENS,L. MI,J. OERTER,B. SANDBERG,J. WARBURTON,D.
Object Type:
Article
System:
The UNT Digital Library