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Sensitivity analysis using parallel ODE solvers and automatic differentiation in C: sensPVODE and ADIC

Description: PVODE is a high-performance ordinary differential equation solver for the types of initial value problems (IVPs) that arise in large-scale computational simulations. often, one wants to compute sensitivities with respect to certain parameters in the IVP. They discuss the use of automatic differentiation (AD) to compute these sensitivities in the context of PVODE. Results on a simple test problem indicate that the use of AD-generated derivative code can reduce the time to solution over finite di… more
Date: September 15, 2000
Creator: Lee, S L & Hovland, P D
Partner: UNT Libraries Government Documents Department
open access

Strong field atomic physics in the mid-infrared

Description: We examine strong field atomic physics in a wavelength region (3-4 microns) where very little work has previously been done. The soft photon energy allows the exploration of one-electron atoms with low binding energies (alkali metals). We find that photoionization spectra differ from rare gas studies at shorter wavelengths due to more complex ion core potentials. Harmonic generation is studied, and we find that harmonic bandwidths are consistent with theory and the possibility of compression to… more
Date: March 15, 2000
Creator: Sheehy, B.; Martin, J. D. D.; Clatterbuck, T. O.; Kim, D. W.; DiMauro, L. F.; Agostini, P. et al.
Partner: UNT Libraries Government Documents Department
open access

Optical and EUV light curves of dwarf nova outbursts

Description: We combine AAVSO and VSS/RASNZ optical and Extreme Ultraviolet Explorer EUV light curves of dwarf novae in outburst to place constraints on the nature of dwarf nova outbursts. From the observed optical-EUV time delays of {approx} 0.75-1.5 days, we show that the propagation velocity of the dwarf nova instability heating wave is {approx} 3 km s{sup -1}.
Date: November 15, 2000
Creator: Mauche, C W; Mattei, J A & Bateson, F M
Partner: UNT Libraries Government Documents Department
open access

Analysis of Bulk DKDP Damage Distribution, Obscuration and Pulse Length Dependence

Description: Recent LLNL experiments reported elsewhere at this conference explored the pulselength dependence of 351 nm bulk damage incidence in DKDP. The results found are consistent, in part, with a model in which a distribution of small bulk initiators is assumed to exist in the crystal and the damage threshold is determined by reaching a critical temperature. The observed pulse length dependence can be explained as being set by the most probable defect capable of causing damage at a given pulselength. … more
Date: December 15, 2000
Creator: Feit, M D; Rubenchik, A M & Runkel, M
Partner: UNT Libraries Government Documents Department
open access

Design of a proof of principle high current transport experiment

Description: Preliminary designs of an intense heavy-ion beam transport experiment to test issues for Heavy Ion Fusion (HIF) are presented. This transport channel will represent a single high current density beam at full driver scale and will evaluate practical issues such as aperture filling factors, electrons, halo, imperfect vacuum, etc., that cannot be fully tested using scaled experiments. Various machine configurations are evaluated in the context of the range of physics and technology issues that can… more
Date: January 15, 2000
Creator: Lund, S. M.; Bangerter, R. O.; Barnard, J. J.; Celata, C. M.; Faltens, A.; Friedman, A. et al.
Partner: UNT Libraries Government Documents Department
open access

Particle Simulations of a Long Pulse Electron Beam in a Bend

Description: Advanced x-ray radiography machines require that multiple electron beam pulses be delivered to x-ray converter targets over several lines of sight. This can be accomplished using a single accelerator by using a fast kicker to deliver the electron beam pulses to several beamlines. This type of radiography machine requires transport lines with several large achromatic bends in the individual transport lines. To maintain a small spot size and a large dose for an x-ray pulse created at the converte… more
Date: August 15, 2000
Creator: Poole, B. R. & Chen, Y. J.
Partner: UNT Libraries Government Documents Department
open access

Effective File I/O Bandwidth Benchmark

Description: The effective I/O bandwidth benchmark (b{_}eff{_}io) covers two goals: (1) to achieve a characteristic average number for the I/O bandwidth achievable with parallel MPI-I/O applications, and (2) to get detailed information about several access patterns and buffer lengths. The benchmark examines ''first write'', ''rewrite'' and ''read'' access, strided (individual and shared pointers) and segmented collective patterns on one file per application and non-collective access to one file per process.… more
Date: February 15, 2000
Creator: Rabenseifner, R. & Koniges, A. E.
Partner: UNT Libraries Government Documents Department
open access

ALS superbend magnet system

Description: The Lawrence Berkeley National Laboratory is preparing to upgrade the Advanced Light Source (ALS) with three superconducting dipoles (Superbends). In this paper we present the final magnet system design which incorporates R&D test results and addresses the ALS operational concerns of alignment, availability, and economy. The design incorporates conduction-cooled Nb-Ti windings and HTS current leads, epoxy-glass suspension straps, and a Gifford-McMahon cryocooler to supply steady state refri… more
Date: September 15, 2000
Creator: Zbasnik, J.; Wang, S. T.; Chen, J. Y.; DeVries, G. J.; DeMarco, R.; Fahmie, M. et al.
Partner: UNT Libraries Government Documents Department
open access

Calibration Facilities for NIF

Description: The calibration facilities will be dynamic and will change to meet the needs of experiments. Small sources, such as the Manson Source should be available to everyone at any time. Carrying out experiments at Omega is providing ample opportunity for practice in pre-shot preparation. Hopefully, the needs that are demonstrated in these experiments will assure the development of (or keep in service) facilities at each of the laboratories that will be essential for in-house preparation for experiment… more
Date: June 15, 2000
Creator: Perry, T. S.
Partner: UNT Libraries Government Documents Department
open access

Influence of Thermal Aging on the Mechanical and Corrosion Properties of C-22 Alloy Welds

Description: The phase stability of C-22 alloy (UNS No. N06022) gas tungsten arc welds was studied by aging samples at 427, 482, 538, 593, 649, 704, and 760 C for times up to 40,000 hours. The tensile properties and the Charpy impact toughness of these samples were measured in the as-welded condition as well as after aging. The corrosion resistance was measured using standard immersion tests in acidic ferric sulfate (ASTM G 28 A) and 2.5% hydrochloric acid solutions at the boiling point. The microstructures… more
Date: June 15, 2000
Creator: Edgecumbe Summers, T. S.; Rebak, R. B. & Seeley, R. R.
Partner: UNT Libraries Government Documents Department
open access

Bottom production

Description: In the context of the LHC experiments, the physics of bottom flavoured hadrons enters in different contexts. It can be used for QCD tests, it affects the possibilities of B decays studies, and it is an important source of background for several processes of interest. The physics of b production at hadron colliders has a rather long story, dating back to its first observation in the UA1 experiment. Subsequently, b production has been studied at the Tevatron. Besides the transverse momentum spect… more
Date: March 15, 2000
Creator: Baines, J.; Baranov, S. P.; Bartalini, P.; Bay, A.; Bouhova, E.; Cacciari, M. et al.
Partner: UNT Libraries Government Documents Department
open access

National energy use of consumer electronics in 1999

Description: The major consumer electronics in U.S. homes accounted for nearly 7 percent of U.S. residential electricity consumption in 1999. We attribute more than half of this figure (3.6 percent) to televisions, videocassette recorders, and DVD players, and nearly one-third (1.8 percent) to audio products. Set-top boxes currently account for a relatively small fraction of residential electricity use (0.7 percent), but we expect this end-use to grow quickly with the proliferation of digital set-top boxes,… more
Date: February 15, 2000
Creator: Rosen, Karen; Meier, Alan & Zandelin, Stefan
Partner: UNT Libraries Government Documents Department
open access

A Moment-Based Condensed History Algorithm

Description: ''Condensed History'' algorithms are Monte Carlo models for electron transport problems, They describe the aggregate effect of multiple collisions that occur when an electron travels a path length s{sub 0}. This path length is the distance each Monte Carlo electron travels between Condensed History steps. Conventional Condensed History schemes employ a splitting routine over the range 0 {le} s {le} s{sub 0}. For example, the Random Hinge method splits each path length step into two substeps; on… more
Date: June 15, 2000
Creator: Tolar, D.R. & Larsen, E.W.
Partner: UNT Libraries Government Documents Department
open access

Studying the Role of Nuclear Structure Effects in Neutron-Induced Reactions Using GEANIE at LANSCE

Description: Efforts to model and measure absolute neutron-induced reaction cross sections have for the most part been limited by experimental techniques to neutron energies found in reactors and light-ion fusion reactions (i.e., t(d,n){alpha} etc.). This can in large part be attributed to the difficulty involved in making high-flux mono-energetic neutron beams with E{sub n} > 14 MeV. The result has been a lack of guidance for (n,xnypz{alpha}) reaction modeling for E{sub n} > 1-2 MeV. These limitation… more
Date: September 15, 2000
Creator: Bernstein, L. A.; Archer, D. E.; Becker, J. A.; Garrett, P. E.; Hauschild, K.; McGrath, C. A. et al.
Partner: UNT Libraries Government Documents Department
open access

Attomole quantitation of protein separations with accelerator mass spectrometry

Description: Quantification of specific proteins depends on separation by chromatography or electrophoresis followed by chemical detection schemes such as staining and fluorophore adhesion. Chemical exchange of short-lived isotopes, particularly sulfur, is also prevalent despite the inconveniences of counting radioactivity. Physical methods based on isotopic and elemental analyses offer highly sensitive protein quantitation that has linear response over wide dynamic ranges and is independent of protein conf… more
Date: December 15, 2000
Creator: Vogel, J. S.; Grant, P. G.; Buccholz, B. A.; Dingley, K. & Turteltaub, K. W.
Partner: UNT Libraries Government Documents Department
open access

Dislocation Dynamics using Anisotropic Elasticity: Methodology and Analysis

Description: A numerical methodology to incorporate anisotropic elasticity into three-dimensional dislocation dynamics codes has been developed, employing theorems derived by Lothe (1967), Brown (1967), Indenbom and Orlov (1968) and Asaro and Barnett (1976). The formalism is based on the stress field solution for a straight dislocation segment of arbitrqq orientation in 3-dimensional space. The general solution is given in a complicated closed integral form. To reduce the computation complexity, look-up tab… more
Date: June 15, 2000
Creator: Rhee, M; Stolken, J S; Bulatov, V V; Diaz de la Rubia, T; Zbib, H M & Hirth, J P
Partner: UNT Libraries Government Documents Department
open access

Proceedings of the 22nd Annual DoD/DOE Seismic Research Symposium: Planning for Verification of and Compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT)

Description: These proceedings contain papers prepared for the 22nd Annual DoD/DOE Seismic Research Symposium: Planning for Verification of and Compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT), held 13-15 September 2000 in New Orleans, Louisiana. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Defense Threat Reduction Agency (DTRA), Air Force Technical Applications Center (AFTAC),… more
Date: September 15, 2000
Creator: Nichols, James W., LTC
Partner: UNT Libraries Government Documents Department
open access

Astrometry with the MACHO Data Archive

Description: We present the preliminary results of our astrometric study of stellar motions along the lines of sight of the Magellanic Clouds and the Galactic bulge. We find that we are able to select stars with proper motions as small as 0.03 inch/yr from five years of PSF photometry due to the characteristic nature of the shapes the light curves of HFM stars. This shape arises from the proper motion of the object relative to the initial fixed centroid location where all photometry of the object is perform… more
Date: October 15, 2000
Creator: Drake, A. J.; Alcock, C.; Allsman, R.; Alves, D. R.; Axelrod, T. S.; Becker, A. C. et al.
Partner: UNT Libraries Government Documents Department
open access

RF photoinjector development for a short-pulse, hard x-ray Thomson scattering source

Description: An important motivation in the development of the next generation x-ray light sources is to achieve picosecond and sub-ps pulses of hard x-rays for dynamic studies of a variety of physical, chemical and biological processes. Present hard x-ray sources are either pulse-width or intensity limited, which allows ps-scale temporal resolution only for signal averaging of highly repetitive processes. A much faster and brighter hard x-ray source is being developed at LLNL, based on Thomson scattering o… more
Date: August 15, 2000
Creator: Le Sage, G P; Anderson, S G; Cowan, T E; Crane, J K; Ditmire, T & Rosenzweig, J B
Partner: UNT Libraries Government Documents Department
open access

Nanostructured energetic materials derived from sol-gel chemistry

Description: Initiation and detonation properties are dramatically affected by an energetic material's microstructural properties. Sol-gel chemistry allows intimacy of mixing to be controlled and dramatically improved over existing methodologies. One material goal is to create very high power energetic materials which also have high energy densities. Using sol-gel chemistry we have made a nanostructured composite energetic material. Here a solid skeleton of fuel, based on resorcinol-formaldehyde, has nanocr… more
Date: March 15, 2000
Creator: Simpson, R. L.; Tillotson, T. M.; Hrubesh, L. W. & Gash, A. E.
Partner: UNT Libraries Government Documents Department
open access

Borehole Effects in Triaxial Induction Logging

Description: Traditional induction tools use source arrays in which both receiving and transmitting magnetic dipoles are oriented along the borehole axis. This orientation has been preferred for traditional isotropic formation evaluation in vertical boreholes because borehole effects are minimized by the source-receiver-borehole symmetry. However, this source-receiver geometry tends to minimize the response of potentially interesting geological features? such as bed resistivity anisotropy and fracturing whi… more
Date: September 15, 2000
Creator: Bertete-Aguirre, H; Cherkaev, E & Tripp, A
Partner: UNT Libraries Government Documents Department
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