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OIT Best Practices
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Direct FuelCell/Turbine Power Plant Progress Report
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Establishment of an Industry-Driven Consortium Focused on Improving the Production Performance of Domestic Stripper Wells Quarterly Report
5
Fiscal Year 2000
4
Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems Quarterly Report
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Fiscal Year 2001
3
Habitat Evaluation Procedures Report
3
Small Wind Electric Systems Consumers' Guides
3
ARM Facilities Newsletter
2
Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipline Leak Detection Progress Report
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Theoretical study of the electronic states of Nb4, Nb5 clusters and their anions (Nb4?, Nb5?)
Geometries and energy separations of the various low-lying electronic states of Nb{sub n} and Nb{sub n}{sup -} (n = 4, 5) clusters with various structural arrangements have been investigated. The complete active space multi-configuration self-consistent field (CASMCSCF) method followed by multi-reference singles and doubles configuration interaction (MRSDCI) calculations that included up to 52 million configuration spin functions have been used to compute several electronic states of these clusters. The ground states of both Nb{sub 4} ({sup 1}A', pyramidal) and Nb{sub 4}{sup -} ({sup 2}B{sub 3g}, rhombus) are low-spin states at the MRSDCI level. The ground state of Nb{sub 5} cluster is a doublet with a distorted trigonal bipyramid (DTB) structure. The anionic cluster of Nb{sub 5} has two competitive ground states with singlet and triplet multiplicities (DTB). The low-lying electronic states of these clusters have been found to be distorted due to Jahn-Teller effect. On the basis of the energy separations of our computed electronic states of Nb{sub 4} and Nb{sub 5}, we have assigned the observed photoelectron spectrum of Nb{sub n}{sup -}(n = 4, 5) clusters. We have also compared our MRSDCI results with density functional calculations. The electron affinity, ionization potential, dissociation and atomization energies of Nb{sub 4} …
Date:
May 6, 2004
Creator:
Balasubramanian, K & Majumdar, D
Object Type:
Article
System:
The UNT Digital Library
Measurement of Low Level Explosives Reaction in Gauged Multi-Dimensional Steven Impact Tests
The Steven Test was developed to determine relative impact sensitivity of metal encased solid high explosives and also be amenable to two-dimensional modeling. Low level reaction thresholds occur at impact velocities below those required for shock initiation. To assist in understanding this test, multi-dimensional gauge techniques utilizing carbon foil and carbon resistor gauges were used to measure pressure and event times. Carbon resistor gauges indicated late time low level reactions 200-540 {micro}s after projectile impact, creating 0.39-2.00 kb peak shocks centered in PBX 9501 explosives discs and a 0.60 kb peak shock in a LX-04 disk. Steven Test modeling results, based on ignition and growth criteria, are presented for two PBX 9501 scenarios: one with projectile impact velocity just under threshold (51 m/s) and one with projectile impact velocity just over threshold (55 m/s). Modeling results are presented and compared to experimental data.
Date:
May 31, 2001
Creator:
Niles, A M; Garcia, F; Greenwood, D W; Forbes, J W; Tarver, C M; Chidester, S K et al.
Object Type:
Article
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
Building America Research is Leading the Way to Zero Energy Homes
During times of peak demand, a near zero energy home generates more power than it uses and reduces power demand on the utility provider. In a Florida study, a prototype near zero energy home outperforms a conventional model by providing most of its own power needs throughout the year.
Date:
May 1, 2005
Creator:
unknown
Object Type:
Text
System:
The UNT Digital Library
Science and Technology Review June 2005
This is the articles in this month's issue: (1) Close Collaborations Advance Progress in Genomic Research--Commentary by Elbert Branscomb; (2) Mining Genomes--Livermore computer programs help locate the stretches of DNA in gene deserts that regulate protein-making genes; (3) Shedding Light on Quantum Physics--Laboratory laser research builds from the foundation of Einstein's description of the quantization of light. (4) The Sharper Image for Surveillance--Speckle imaging-an image-processing technique used in astronomy is bringing long-distance surveillance into sharper focus. (5) Keeping Cool Close to the Sun--The specially coated gamma-ray spectrometer aboard the MESSENGER spacecraft will help scientists determine the abundance of elements in Mercury's crust.
Date:
May 3, 2005
Creator:
Aufderheide, M
Object Type:
Report
System:
The UNT Digital Library
Practical Issues Associated with Mortar Projections in Large Deformation Contact/Impact Analysis
Several recent works have considered variants of the mortar-finite element method for numerical treatment of contact phenomena. The method has shown considerable promise for the spatial discretization of contact interactions, particularly for kinematically linear applications where one or both of the contacting surfaces are flat. Desirable features already demonstrated for the method in this specialized setting include passage of patch tests, preservation of convergence rates that would be obtained with a perfectly conforming mesh, and accurate resolution of contact stresses on interfaces. This paper concerns itself with the successful extension of these methods to encompass contact of geometrically noncoincident surfaces. The issue of patch test passage over curved interfaces will be discussed. It will be shown that a generalization of the mortar projection method is required to pass patch tests in this instance. Issues relating to the exact numerical integration of the mortar projection integrals will also be outlined, and a convergence study for a mortar tying application will be presented.
Date:
May 2, 2002
Creator:
Laursen, T. A.; Puso, M. A. & Heinstein, M. W.
Object Type:
Article
System:
The UNT Digital Library
Cooperative MPC&A Enhancements at Russian Navy Sites
U.S. MPC&A cooperation with the Russian Federation (RF) Navy is based on a Joint Statement signed in 1996 to protect Highly Enriched Uranium (HEU) fresh fuel used for nuclear propulsion. The Russian Federation Navy is the largest owner in Russia of highly enriched uranium, both in the form of fresh nuclear fuel, and in the form of slightly irradiated fuel with a long cooling time after irradiation. As a result of this agreement, projects began at the Northern Fleet Fresh Fuel Storage Facility (Site 49) and Refueling Ship PM-63. Initial projects provided upgrades for RF Navy HEU fresh fuel storage facilities, beginning with a land-based facility near Murmansk and later adding other land-based and ship-based fresh fuel storage facilities. Additional protocols (December 1997, January 1999, and March 2000) significantly expanded cooperation to include all HEU fuel under RF Navy control. To date, it is estimated that tens of metric tons of HEU have been secured - enough to construct hundreds of nuclear devices. It was determined that the cooperation would be coordinated by the Russian Research Center, Kurchatov Institute. This paper describes the history of the Program development, its stages, current status, scale of the work and prospects.
Date:
May 30, 2001
Creator:
Nelson, N. N.; O'Shell, P.; Hendrickson, S.; Sukhoruchkin, V.; Antipov, S.; Melkhov, E. et al.
Object Type:
Article
System:
The UNT Digital Library
DESIGN, CONSTRUCTION, AND STATUS OF ALL NIOBIUM SUPERCONDUCTING PHOTOINJECTOR AT BNL.
We present here the design and construction of an all niobium superconducting RF injector to generate high average current, high brightness electron beam. A 1/2 cell superconducting cavity has been designed, built, and tested. A cryostat has been built to cool the cavity to {approx}2 K. The RF system can deliver up to 500 W at 1.3 GHz to the cavity. A mode-locked Nd:YVO{sub 4} laser, operating at 266 nm with 0.15 W average power, phase locked to the RF, will irradiate a laser cleaned Nb surface at the back wall of the cavity. Description of critical components and their status are presented in the paper. Based on DC measurements, QE of up to 10{sup 4} can be expected from such cavity.
Date:
May 12, 2004
Creator:
SRINIVASAN-RAO,T. BEN-ZVI,I. BURRILL,A. CITVER,G. ET AL.
Object Type:
Article
System:
The UNT Digital Library
Non-Equilibrium Zeldovich-Von Neumann-Doring Theory and Reactive Flow Modeling of Detonation
This paper discusses the Non-Equilibrium Zeldovich - von Neumann - Doring (NEZND) theory of self-sustaining detonation waves and the Ignition and Growth reactive flow model of shock initiation and detonation wave propagation in solid explosives. The NEZND theory identified the non-equilibrium excitation processes that precede and follow the exothermic decomposition of a large high explosive molecule into several small reaction product molecules. The thermal energy deposited by the leading shock wave must be distributed to the vibrational modes of the explosive molecule before chemical reactions can occur. The induction time for the onset of the initial endothermic reactions can be calculated using high pressure, high temperature transition state theory. Since the chemical energy is released well behind the leading shock front of a detonation wave, a physical mechanism is required for this chemical energy to reinforce the leading shock front and maintain its overall constant velocity. This mechanism is the amplification of pressure wavelets in the reaction zone by the process of de-excitation of the initially highly vibrationally excited reaction product molecules. This process leads to the development of the three-dimensional structure of detonation waves observed for all explosives. For practical predictions of shock initiation and detonation in hydrodynamic codes, …
Date:
May 2, 2002
Creator:
Tarver, C M; Forbes, J W & Urtiew, P A
Object Type:
Article
System:
The UNT Digital Library
Analysis of the Use of Wind Energy to Supplement the Power Needs at McMurdo Station and Amundsen-Scott South Pole Station, Antarctica
This report summarizes an analysis of the inclusion of wind-driven power generation technology into the existing diesel power plants at two U.S. Antarctic research stations, McMurdo and Amundsen-Scott South Pole Station. Staff at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) conducted the analysis. Raytheon Polar Services, which currently holds the private sector support contract for the two research stations, was a major contributor to this report. To conduct the analysis, available data were obtained on the wind resources, power plant conditions, load, and component cost. Whenever possible, we validated the information. We then used NREL's Hybrid2 power system modeling software to analyze the potential and cost of using wind turbine generators at the two aforementioned facilities. Unfortunately, the power systems and energy allocations at McMurdo and South Pole Station are being redeveloped, so it is not possible to validate future fuel use. This report is an initial assessment of the potential use of wind energy and should be followed by further, more detailed analysis if this option is to be considered further.
Date:
May 1, 2005
Creator:
Baring-Gould, I.; Robichaud, R. & McLain, K.
Object Type:
Report
System:
The UNT Digital Library
Multi-Tube Power Leads Tower for Bepcii Ir Magnets.
A power lead tower containing the multi-tube power leads is designed and under fabrication for the superconducting IR quadrupole magnets in the Beijing Electron Position Collider Upgrade (BEPCII). The lead tower consists of six pairs of gas-cooled leads for seven superconducting coils at various operating currents. The power lead is designed in a modular fashion, which can be easily applied to suit different operating current. The end copper block of the tube lead has a large cold mass that provide a large time constant in case of cooling flow interruption. A novel cryogenic electrical isolator is used for the leads.
Date:
May 11, 2004
Creator:
Jia, L. X.; Zhang, X. B.; Wang, L.; Wang, T. H. & Yao, Z. L.
Object Type:
Article
System:
The UNT Digital Library
Fitting the luminosity decay in the Tevatron
This paper explores how to fit the decay of the luminosity in the Tevatron. The standard assumptions of a fixed-lifetime exponential decay are only appropriate for very short time intervals. A ''1/time'' functional form fits well, and is supported by analytical derivations. A more complex form, assuming a time-varying lifetime-like term, also produces good results. Changes in the luminosity can be factored into two phenomena: The luminosity burn-off rate, and the burn-off rate from non-luminosity effects. This is particularly relevant for the antiprotons in the Tevatron. The luminous and the non-luminous burn rate of the antiprotons are shown for Tevatron stores.
Date:
May 1, 2005
Creator:
McCrory, E.; Shiltsev, V.; Slaughter, A. J. & Xiao, A.
Object Type:
Article
System:
The UNT Digital Library
Using star tracks to determine the absolute pointing of the Fluorescence Detector telescopes of the Pierre Auger Observatory
To accurately reconstruct a shower axis from the Fluorescence Detector data it is essential to establish with high precision the absolute pointing of the telescopes. To d that they calculate the absolute pointing of a telescope using sky background data acquired during regular data taking periods. The method is based on the knowledge of bright star's coordinates that provide a reliable and stable coordinate system. it can be used to check the absolute telescope's pointing and its long-term stability during the whole life of the project, estimated in 20 years. They have analyzed background data taken from January to October 2004 to determine the absolute pointing of the 12 telescopes installed both in Los Leones and Coihueco. The method is based on the determination of the mean-time of the variance signal left by a star traversing a PMT's photocathode which is compared with the mean-time obtained by simulating the track of that star on the same pixel.
Date:
May 1, 2005
Creator:
De Donato, Cinzia; Sanchez, Federico; /Milan U. /INFN, Milan; Santander, Marcos; Natl.Tech.U., San Rafael; Camin, Daniel et al.
Object Type:
Article
System:
The UNT Digital Library
Advances in the understanding and operations of superconducting colliders
Chromaticity drift during injection is a well-known phenomenon in superconducting colliders, such as the Tevatron, HERA and RHIC. Imperfect compensation of the drift effects can contribute to beam loss and emittance growth. It is caused by the drift of the sextupole component in the dipole magnets due to current redistribution in its superconducting coils. Recently extensive studies of chromaticity drift were conducted at the Tevatron, aiming at the improvement of the luminosity performance in the ongoing run II. These studies included not only beam experiments, but also extensive off-line magnetic measurements on spare Tevatron dipoles. Less known, until recently, is that chromaticity drift is often accompanied by tune and coupling drift. This was recently discovered in the Tevatron. We believe that these effects are the product of systematic beam offset in conjunction with the sextupole drifts (and their compensation in the chromaticity correctors). These discoveries are most relevant to the upcoming LHC, where the drift effects will have even more dramatic consequences given the high beam current. It is therefore not a surprise that CERN has been the source of major advances in the understanding of dynamic effects during the LHC superconducting magnet development. The following will briefly review the …
Date:
May 1, 2005
Creator:
Annala, G.; Bauer, P.; Bottura, L.; Martens, M. A.; Sammut, N.; Velev, G. et al.
Object Type:
Article
System:
The UNT Digital Library
The ASCI PSE Milepost: Run-Time Systems Performance Tests
The Accelerated Strategic Computing Initiative (ASCI) Problem Solving Environment (PSE) consists of the tools and libraries needed for the development of ASCI simulation codes on ASCI machines. The recently completed ASCI PSE Milepost demonstrated that this software environment is available and functional at the scale used for application mileposts on ASCI White. As part of the PSE Milepost, we performed extensive performance testing of several critical run-time based systems. In this paper, we present microbenchmark results that compare the MPI [5], Pthreads and OpenMP [7, 8] implementations on ASCI White and ASCI Blue Pacific. Our results demonstrate that these run-time systems on White have improved sufficiently to accommodate the machine's approximately four-fold increase in processing capability over Blue Pacific.
Date:
May 7, 2001
Creator:
de Supinski, B R
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
US accelerator contribution to the LHC
In 1998, the United States entered into an agreement with CERN to help build the Large Hadron Collider (LHC), with contributions to the accelerator and to the large HEP detectors. To accomplish this, the US LHC Accelerator Project was formed, encompassing expertise from Brookhaven National Laboratory (BNL), Fermi National Accelerator Laboratory (FNAL) and the Lawrence Berkeley National Laboratory (LBNL). This report is a summary of these contributions including the progress towards project completion, as well as a discussion of future plans for continued US participation in the LHC accelerator.
Date:
May 1, 2005
Creator:
Lamm, Michael J.
Object Type:
Article
System:
The UNT Digital Library
Transforming the Market for Sustainable Design: Effective Public Policies and Strategies; Preprint
The federal government strives to lead by example in energy and resource management and architectural design. This paper explores how public agencies are supporting that goal by using sustainable practices in the design and operation of their buildings. It presents some elements to consider in establishing a policy for sustainable design and a system for implementing that policy, including some of the most difficult implementation issues agencies have to face. The paper also highlights some of the strengths and weaknesses of federal, state, and local policies and practices governing the design of public buildings; two case studies provide examples. Different approaches are included to help agencies evaluate their effectiveness at various levels of government. And recommendations are made for agencies and others who are committed to sustainable design in both new construction and major renovations.
Date:
May 1, 2004
Creator:
Carlisle, N.; Glickman, J.; Brown, M.; Foster, M.; Bennett, A. K. & Sandler, K.
Object Type:
Article
System:
The UNT Digital Library
Detection of Pathogens Using a Handheld PCR Thermocycler
None
Date:
May 14, 2001
Creator:
Emanuel, P; Hadfield, T; Koopman, R; Richards, J; Benett, W; Stratton, P et al.
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
Field quality study in Nb(3)Sn accelerator magnets
Four nearly identical Nb{sub 3}Sn dipole models of the same design were built and tested at Fermilab. It provided a unique opportunity of systematic study the field quality effects in Nb{sub 3}Sn accelerator magnets. The results of these studies are reported in the paper.
Date:
May 1, 2005
Creator:
Kashikhin, V. V.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; DiMarco, J. 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
Intracavity adaptive correction of a 10 kW, solid-state, heat-capacity laser
The Solid-State, Heat-Capacity Laser (SSHCL), under development at Lawrence Livermore National Laboratory (LLNL) is a large aperture (100 cm{sup 2}), confocal, unstable resonator requiring near-diffraction-limited beam quality. There are two primary sources of the aberrations in the system: residual, static aberrations from the fabrication of the optical components and predictable, time-dependent, thermally-induced index gradients within the gain medium. A deformable mirror placed within the cavity is used to correct the aberrations that are sensed externally with a Shack-Hartmann wavefront sensor. Although the complexity of intracavity adaptive correction is greater than that of external correction, it enables control of the mode growth within the resonator, resulting in the ability to correct a more aberrated system longer. The overall system design, measurement techniques and correction algorithms are discussed. Experimental results from initial correction of the static aberrations and dynamic correction of the time-dependent aberrations are presented.
Date:
May 13, 2004
Creator:
LaFortune, K N; Hurd, R L; Brase, J M & Yamamoto, R M
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