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An efficient algorithm to compute row and column counts for sparse Cholesky factorization

Description: Let an undirected graph G be given, along with a specified depth- first spanning tree T. We give almost-linear-time algorithms to solve the following two problems: First, for every vertex v, compute the number of descendants w of v for which some descendant of w is adjacent (in G) to v. Second, for every vertx v, compute the number of ancestors of v that are adjacent (in G) to at least one descendant of v. These problems arise in Cholesky and QR factorizations of sparse matrices. Our algorithms can be used to determine the number of nonzero entries in each row and column of the triangular factor of a matrix from the zero/nonzero structure of the matrix. Such a prediction makes storage allocation for sparse matrix factorizations more efficient. Our algorithms run in time linear in the size of the input times a slowly-growing inverse of Ackermann's function. The best previously known algorithms for these problems ran in time linear in the sum of the nonzero counts, which is usually much larger. We give experimental results demonstrating the practical efficiency of the new algorithms.
Date: September 1, 1992
Creator: Gilbert, J. R. (Xerox Palo Alto Research Center, CA (United States)); Ng, E. G. & Peyton, B. W. (Oak Ridge National Lab., TN (United States))

epsilon. prime /. epsilon. and heavy top

Description: The article reviews the new theoretical developments for the CP-parameter {epsilon}{prime}/{epsilon} and its intimate connection with the mass of a heavy top quark. 22 refs., 8 figs., 1 tab.
Date: March 1, 1990
Creator: Paschos, E. A. (Fermi National Accelerator Lab., Batavia, IL (USA)); Schneider, T. (Dortmund Univ. (Germany, F. R.). Inst. fuer Physik) & Wu, Y. L. (Mainz Univ. (Germany, F. R.). Inst. fuer Physik)

Development of a new plasma diagnostic of the critical surface and studies of the ion acoustic decay instability using collective Thomson scattering

Description: We have developed 5-channel collective Thomson scattering system to measure the ion acoustic wave excited by the ion acoustic wave decay instabilities. The multichannel collective Thomson scattering technique was established with 4{omega} probe laser beam using GDL laser system at LLE, Univ. of Rochester. We have obtained the ionic charge state Z by measuring the second harmonic emission from the ion acoustic decay instability. The LASNEX computer simulation calculations have been carried out. The experimental results agree very well with the LASNEX computer simulation results with the flux number f=0.l. In high power laser regime, the spectrum become broad, and the {Delta}{gamma} decreases indicating that the turbulent like spectrum is observed. In order to understand the experimental results, we have developed a theory to study absorption of laser and heat transport. This new theory includes the temporal evolution of the heat conduction region. The results agree with flux-limited hydrodynamic simulations.
Date: January 1, 1992
Creator: Mizuno, K.; DeGroot, J. S. (California Univ., Davis, CA (United States)); Seka, W. (Rochester Univ., NY (United States). Lab. of Laser Energetics) & Drake, R. P. (Lawrence Livermore National Lab., CA (United States))

Physics models and user's guide for the neutral beam module of the SUPERCODE

Description: This report contains a description of the neutral beam heating and current drive module Beams, that was developed at Georgia Tech for the SUPERCODE, the new systems and operations code for the ITER EDA. The NB module calculates profiles of the neutral beam deposition, fast ion pressure, beam heating power, and neutral beam driven current density. It also computes global parameters such as current drive efficiencies, beam shinethrough, fast beam ion beta, and the fusion power and neutron production due to beam-plasma interactions. The most important consideration during the development of this module was to make it compute normally fast without compromising physical accuracy. We believe that through careful selection of physical models and optimized coding, these conflicting requirements have been largely met. As a result, the SUPERCODE has now the ability to perform self-consistent calculations involving NB heating and current drive. This capability is very important for the study of sub-ignited, hybrid, or steady-state ITER and post-TFIR reactor operating scenarios. It is also the first time that a systems code has had such capabilities, usually found only in 1-1/2D plasma transport codes.
Date: August 1, 1992
Creator: Mandrekas, J.

South Fork Clearwater River Habitat Enhancement, Nez Perce National Forest.

Description: In 1984, the Nez Perce National forest and the Bonneville Power Administration entered into a contractual agreement which provided for improvement of spring chinook salmon and summer steelhead trout habitat in south Fork Clearwater River tributaries. Project work was completed in seven main locations: Crooked River, Red River, Meadow Creek Haysfork Gloryhole, Cal-Idaho Gloryhole, Fisher Placer and Leggett Placer. This report describes restoration activities at each of these sites.
Date: April 1, 1992
Creator: Siddall, Phoebe

Analytical prediction of thermal performance of hypervapotron and its application to ITER

Description: A hypervapotron (HV) is a water cooled device made of high thermal conductivity material such as copper. A surface heat flux of up to 30 MW/m{sup 2} has been achieved in copper hypervapotrans cooled by water at a velocity of 10 m/s and at a pressure of six bar. Hypervapotrons have been used in the past as beam dumps at the Joint European Torus (JET). It is planned to use them for diverter cooling during Mark II upgrade of the JET. Although a large amount of experimental data has been collected on these devices, an analytical performance prediction has not been done before due to the complexity of the heat transfer mechanisms. A method to analytically predict the thermal performance of the hypervapotron is described. The method uses a combination of a number of thermal hydraulic correlations and a finite element analysis. The analytical prediction shows an excellent agreement with experimental results over a wide range of velocities, pressures, subcooling, and geometries. The method was used to predict the performance of hypervapotron made of beryllium. Merits for the use of hypervapotrons for International Thermonuclear Experimental Reactor (ITER) and Tokamak Physics Experiment (TPX) are discussed.
Date: September 1, 1992
Creator: Baxi, C. B. (General Atomics, San Diego, CA (United States)) & Falter, H. (JET Joint Undertaking, Abingdon (United Kingdom))

Accessibility for lower hybrid waves in PBX-M

Description: Understanding the wave damping mechanism in the presence of a spectral gap' is an important issue for the current profile control using Lower Hybrid Current Drive (LHCD). The authors examine a traditional explanation based upon upshifting of the wave parallel refractive index (n[sub [parallel]]) and find that there can be an upper bound in the n[sub [parallel]] upshift. The amount of upshift is not sufficient to bridge the spectral gap completely under some PBX-M LHCD conditions. There is experimental evidence, however, that current was driven even under such conditions. Another mechanism is also considered, based upon the 2-D velocity space dynamics coupled with a compound wave spectrum, here consisting of forward- and backward-running waves. The runaway critical speed relative to the phase speeds of these waves plays an important role in this model.
Date: July 1, 1993
Creator: Takahashi, H.; Bell, R.; Bernabei, S.; Chance, M.; Chu, T. K.; Gettelfinger, G. et al.

Production of mild gasification coproducts

Description: The LFC process upgrades young coals and lignites to a solid fuel which resembles higher rank coals and coproduces a liquid that resembles fuel oil. During the natural metamorphic process of pressure and heat, younger lower rank coals are converted to older higher rank coals over a period of greater than 100 million years. SGI's LFC process accomplishes this transformation in less than an hour, producing solid Process Derived Fuel (PDF) and liquid Coal Derived Liquid (CDL) coproducts. The coproduct samples will be produced from 4 different coals gathered from 3 major coal resource regions of the United States. Samples of the LFC process coproducts will be delivered to Government laboratories for test and characterization. Twenty kilograins of PDF will be delivered to each of 3 laboratories and 2 laters of CDL will be delivered to each of 4 laboratories. The characterization information will be returned to SGI and then will be incorporated into the final report.
Date: January 1, 1992
Creator: Horne, D. A. & Watson, P. A.

Chemistry of coal-related microparticles

Description: This research project involves the study of coal macerals and sorbent microparticles used to remove S0{sub 2} and/or H{sub 2}S from process streams. To measure reaction rates a charged single microparticle will be held electrodynamically in one or more laser beams by superposed ac and dc electrical fields. The use of the electrodynamic balance for microparticle studies was pioneered by one of the principal investigators. One of the laser beams is used for light-scattering measurements to determine the particle size and to provide the excitation source for obtaining Raman spectra to chemically characterize the particle. The other beam, an infrared beam, is used to heat the particle electromagnetically. The first year of the research was devoted to preliminary experimental work and design studies. Although components and techniques must still be developed, experimental measurements on single macerals are now being done.
Date: May 26, 1992
Creator: Davis, J. E. & Krieger-Brockett, B.

Criticality safety and shielding design issues in the development of a high-capacity cask for truck transport

Description: General Atomics (GA) will be submitting an application for certification to the US Nuclear Regulatory Commission (NRC) for the GA-4 and GA-9 Casks In 1992. The GA-4 and GA-9 Casks are high-capacity legal weight truck casks designed to transport light water reactor spent fuel assemblies. To maintain a capacity of four pressurized-water-reactor (PWR) spent fuel assemblies, the GA-4 Cask uses burnup credit as part of the criticality control for initial enrichments over 3.0 wt% U-235. Using the US Department of Energy (DOE) Burnup Credit Program as a basis, GA has performed burnup credit analysis which is included in the Safety Analysis Report for Packaging (SARP). The GA-9 Cask can meet the criticality safety requirements using the fresh fuel'' assumption. Our approach to shielding design is to optimize the GA-4 and GA-9 Cask shielding configurations for minimum weights and maximum payloads. This optimization involves the use of the most effective shielding material, square cross-section geometry with rounded corners and tapered neutron shielding sections in the non-fuel regions.
Date: January 1, 1992
Creator: Boshoven, J. K.

Committee on Radiation Epidemiological Research Programs

Description: The Committee on DoE Radiation Epidemiological Research Programs was originally established in response to the needs of the Office of Health and Envirorunental Research, Office of Energy Research in the Department of Energy (DoE). Following a reorganization of DoE health related programs in 1990, the committee now advises the Office of Epidemiology and Health Surveillance which is under the Assistant Secretary for Environment, Safety and Health. These administrative changes have not altered the committee concerns but have served to focus the committee's attention on helping DoE plan for an effective system of worker health surveillance as well as an epidemiologic research program.
Date: June 1, 1992
Creator: Mahlum, D. D.

Single-station integral measures of atmospheric stagnation, ventilation, and recirculation

Description: In air pollution work, terms such as stagnation, ventilation, and recirculation have come to be used to indicate special types of flow conditions that produce important effects on the dispersion of air pollutants. Stagnations are events where atmospheric flows decrease in speed, or stop altogether, allowing pollutants to build up in stagnant air in the vicinity of the pollutant sources. Ventilations, on the other hand, are events in which a confined polluted air mass is driven away and replaced by fresh air. Finally, a recirculation is an event in which polluted air is initially carried away from the source region but later returns to produce a high pollution episode. The three terms, when used in air pollution work, are often used in a general sense, but rarely are defined mathematically to allow a numerical evaluation of the flow character. In the present work we develop mathematical definitions of these terms by focusing directly on the relevant atmospheric transport conditions, irrespective of pollution levels. The mathematical definitions of several single- station integral quantities representative of stagnation, ventilation, and recirculation are described, and the approach is applied to a wind data et from a radar profiler at Page, Arizona.
Date: September 1, 1992
Creator: Allwine, K. J. & Whiteman, C. D.

Six dimensional tracking simulator for H[sup [minus]] injection in AGS Booster

Description: The effect of Coulomb multipole scattering on the beam emittance is studied with the 6 dimensional injection program ARCHSIM by A. Thiessen. Since the energy loss due to Bhabha scattering is small, the six dimensional simulation can be approximated into transverse 4 dimensional and longitudinal 2 dimensional tracking. The emittance growth agrees well with the multiple scattering theory. The beam loss occurs mainly in the adiabatic capture process in the longitudinal phase space.
Date: April 27, 1993
Creator: Lee, S. Y. & Tepikian, S.

Spray nozzle pattern test for the DWPF HEME Task QA Plan. [Defense Waste Processing Facility (DWPF), High Efficiency Mist Eliminator (HEME)]

Description: The DWPF melter off-gas systems have two High Efficiency Mist Eliminators (HEME) upstream of the High-Efficiency Particulates Air filters (HEPA) to remove fine mists and particulates from the off-gas. To have an acceptable filter life and an efficient operation, an air atomized water is spray on the HEME. The water spray keeps the HEME wet and dissolves the soluble particulates and enhances and HEME efficiency. DWPF Technical asked SRL to determine the conditions which will give satisfactory atomization and distribution of water so that the HEME will operate efficiently. The purpose of this document is to identify, QA controls to be applied in the pursuit of this task (WSRC-RP-91-1151).
Date: November 25, 1991
Creator: Lee, L.

Simulation of vortex-line pinning by defects in the Y-Ba-Cu-O system

Description: The temperature properties of a two-dimensional flux lattice are studied by Monte Carlo simulation, with particular attention to the effects of twin-boundaries. The parameters selected are appropriate for the YBa{sub 2}CU{sub 3}0{sub 7} high-temperature superconducting system. The intrinsic properties of the vortex state are investigated by monitoring system evolution at fixed temperature and applied magnetic field. By varying the temperature, the loss of type-II superconductivity via fluxoid lattice melting is also examined. The introduction of model defects induces the creation of metastable and glassy states which reduce overall hexane order but are found to enhance system resistance to flux-lattice melting.
Date: March 1, 1992
Creator: Jamison, R.; Burmester, C. P.; Gronsky, R. (Lawrence Berkeley Lab., CA (United States)) & Wille, L. T. (Florida Atlantic Univ., Boca Raton, FL (United States). Dept. of Physics)

Single parameter analysis of hysteretic magnetic flux trapping in high T[sub c] superconductor ribbon

Description: This paper described the application of an AC surface probe, similar to presently used eddy current probes, to the measurement of DC transport critical currents and critical state dissipation in high [Tc] superconductors. It has been shown that the probe can provide quantitative measurement of the full field penetration in superconducting samples by measuring the response of AC induced screening currents for superconducting materials in the form of tapes with overlayers of silver. In this manner, the AC probe can be used to replace the contact DC probe for determining critical currents in a noncontacting and local manner suitable for scanning over or along the sample.
Date: January 1, 1992
Creator: Telschow, K. L.

Extraction, separation and analysis of high sulfur coal

Description: As mentioned in the previous report, an alternate plan of attack was to try to oxidize the sulfur in coal in a nonaqueous solvent, such as DMF. Copper oxidation reactions are known to have much greater reaction rates in apolar solvents such as DMF. In this experiment the reaction solvent was 50 % v/v H{sub 2}0-DMF with 14% CuCl{sub 2} dissolved in it. The coal sample used was Illinois {number sign}6. The reaction temperature used was 95{degrees}C and the reaction time was 17 hrs. The remaining coal solid was then sent to Blackrock Test Labs, Morgantown, WV for analysis of sulfur in the extracted coal sample. The original sample of Illinois {number sign}6 has 4.83% total sulfur content, of which, 2.81% was pyrite, 0.01% was sulfate and 2.01% was organosulfur species with 14.25% ash. The results obtained from Blackrock show that total sulfur content after reaction was 1.75% of which 0.54% was pyrite, 0.20% was sulfate and 1.01% was organic sulfur with an ash content of 25%. This reaction shows considerable promise in that approximately 50% of the organosulfur type compounds were eliminated along with similar proportions of pyrite. The resulting ash content is still too high. The major contribution to the ash content is not destroyed coal but inorganic copper salts. We have yet to determine the specific nature of these salts but for this to be a viable technique these inorganic species must stay in solution rather than precipitating out onto the coal. The required stoichiometry of the oxidation reaction also has not been determined yet. The quantity of copper salt in solution was kept high to force the reaction to completion.
Date: January 1, 1991
Creator: Olesik, S. (comp.)

Factors affecting mutational specificity induced by ionizing radiation and oxidizing radicals

Description: We propose to analyze the factors affecting the specificity of mutational change as induced by ionizing radiation and oxidizing radicals. We want to understand not only the rules the affect base substitution but also the mechanisms(s) by which additions and deletions are produced, since deletions are a common consequence of radiation. We wish to carry out this analysis in an in vitro mutation system that permits us to analyze the role of base sequence, of polymerase and of mutagenic agent. Our system is designed to screen out most direct breaks as a cause of mutation and should indicate the changes resulting from base damage to the DNA. Questions addressed include: 1. What types of base substitution mutations are induced by ionizing radiation and oxidizing radicals 2. Are deletions and/or additions produced 3. Is there a difference in type of mutation produced dependent on the polymerase used Do mammalian polymerase plus their accessory factors result in different patterns of mutation. 4. What is the mechanism by which base damage is converted to mutation. Our proposal was based on utilization of an in vitro system in which mutations generated by the in vitro copying of a reporter gene sequence could be readily scored.
Date: January 1, 1992
Creator: Strauss, B.

Plasma flow switch and foil implosion experiments on Pegasus II

Description: Pegasus II is the upgraded version of Pegasus, a pulsed power machine used in the Los Alamos AGEX (Above Ground EXperiments) program. A goal of the program is to produce an intense (> 100 TW) source of soft x-rays from the thermalization of the kinetic energy of a 1 to 10 MJ plasma implosion. The radiation pulse should have a maximum duration of several 10's of nanoseconds and will be used in the study of fusion conditions and material properties. The radiating plasma source will be generated by the thermalization of the kinetic energy of an imploding cylindrical, thin, metallic foil. This paper addresses experiments done on a capacitor bank to develop a switch (plasma flow switch) to switch the bank current into the load at peak current. This allows efficient coupling of bank energy into foil kinetic energy.
Date: January 1, 1993
Creator: Cochrane, J. C.; Bartsch, R. R.; Benage, J. R.; Forman, P. R.; Gribble, R. F.; Ladish, J. S. et al.

A neutron dose detector with REM response to 1 GeV

Description: The limitation of current remmeters, which do not measure neutron dose equivalents above about 15 MeV, is a serious problem at high-energy accelerator facilities, where a much wider range of neutron energies exist. The purpose of this work was to measure the response of a modified Anderson-Braun (A-B) remmeter to neutron energies up to 1 GeV. The modifications to the standard A-B remmeter were based on the experimental results of Pb(n,xn) reactions.
Date: July 1, 1992
Creator: Sun, R. K.; Krebs, G. F.; Smith, A. R. (Lawrence Berkeley Lab., CA (United States)) & Hsu, H. H. (Los Alamos National Lab., NM (United States))

A new measurement of CP violation parameter. var epsilon. prime /. var epsilon

Description: The E731 experiment at Fermilab has measured the CP violation parameter Re({var epsilon}{prime}/{var epsilon}) in K{sub L,S}{yields}{pi}{pi} decay. Four decay modes were collected simultaneously to reduce systematic errors. The result is Re({var epsilon}{prime}/{var epsilon})={minus}0.0005 {plus minus} 0.0014 (stat.) {plus minus} 0.0006 (syst.), and gives no evidence for direct CP violation. 7 refs., 3 figs., 1 tab.
Date: January 1, 1990
Creator: Yamanaka, Taku.