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  • 1
    Electronic Resource
    Electronic Resource
    Observation of reduced beam deflection using smoothed beams in gas-filled hohlraum symmetry experiments at Nova (2000)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 7 (2000), S. 1609-1613 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Execution and modeling of drive symmetry experiments in gas-filled hohlraums have been pursued to provide both a better understanding of radiation symmetry in such hohlraums and to verify the accuracy of the design tools which are used to predict target performance for the National Ignition Facility (NIF) [J. Lindl, Phys. Plasmas 2, 3933 (1995)]. In this paper, the results of a series of drive symmetry experiments using gas-filled hohlraums at the Nova laser facility [C. Bibeau et al., Appl. Opt. 31, 5799 (1992)] at Lawrence Livermore National Laboratory are presented. A very important element of these experiments was the use of kineform phase plates (KPP) to smooth the Nova beams. The effect of smoothing the ten Nova beams with KPP phase plates is to remove most of the beam bending which had been observed previously, leaving a residual bending of only 1.5°, equivalent to a 35 μm pointing offset at the hohlraum wall. The results show that the symmetry variation with pointing of implosions in gas-filled hohlraums is consistent with time integrated modeling. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.873982
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  • 2
    Electronic Resource
    Electronic Resource
    Indirect drive experiments utilizing multiple beam cones in cylindrical hohlraums on OMEGA : The 39th annual meeting of division of plasma physics of APS (1998)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 5 (1998), S. 1960-1965 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Current plans for time-dependent control of flux asymmetry in the National Ignition Facility [J. A. Paisner, J. D. Boyes, S. A. Kumpan, and M. Sorem, "The National Ignition Facility Project," ICF Quart. 5, 110 (1995)] hohlraums rely on multiple beam cones with different laser power temporal profiles in each cone. Experiments with multiple beam cones have begun on the Omega laser facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] at the University of Rochester. In addition to allowing symmetry experiments similar to those performed on Nova [A. Hauer et al., Rev. Sci. Instrum. 66, 672 (1995)], the Omega facility allows multiple beam cones to be moved independently to confirm our ability to model the resulting implosion image shapes. Results indicate that hohlraum symmetry behaves similarly with multiple rings of beams as with a single ring, but with the weighted beam spot position used to parametrize the beam pointing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.872866
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  • 3
    Electronic Resource
    Electronic Resource
    Symmetry experiments in gas-filled hohlraums at NOVA (1996)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 3 (1996), S. 2022-2028 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Understanding drive symmetry in gas-filled hohlraums is currently of interest because the baseline design of the indirect drive ignition target for the planned National Ignition Facility uses a gas-filled hohlraum. This paper reports on the results of a series of experiments performed at the Nova laser [C. Bibeau et al. Appl. Opt. 31, 5799 (1992)] facility at Lawrence Livermore National Laboratory with the goal of understanding time-dependent drive symmetry in gas filled hohlraums. Time-dependent symmetry data from capsule implosions and reemission targets in gas-filled hohlraums are discussed. Results of symmetry measurements using thin wall gas-filled hohlraums are also discussed. The results show that the gas is effective in impeding the motion of the wall blowoff material, and that the resulting implosion performance of the capsule is not significantly degraded from vacuum results. The implosion symmetry in gas differs from vacuum results with similar laser pointing indicating a shift in beam position on the hohlraum wall and hotter drive at the capsule's poles than at the equator. A theory has been proposed to explain the observed shift as a plasma physics effect: beam steering due to filamentation and transverse plasma flows. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.871999
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  • 4
    Electronic Resource
    Electronic Resource
    Insecticide Evaluation, Determination of Allethrin Residues in Milk and Meats (1958)
    s.l. : American Chemical Society
    Journal of agricultural and food chemistry 6 (1958), S. 463-465 
    Details
    ISSN: 1520-5118
    Source: ACS Legacy Archives
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jf60088a007
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  • 5
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    The Alaskan Boundary (1899)
    Boston, Mass., etc. : Periodicals Archive Online (PAO)
    The North American Review. 169 (1899:July/Dec.) 501 
    Details
    ISSN: 0029-2397
    Topics: English, American Studies , History
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:3197-1899-169-00-000047
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  • 6
    Electronic Resource
    Electronic Resource
    Concealment of neonatal cerebral infarction on MRI by normal brain water (1987)
    Springer
    Pediatric radiology 17 (1987), S. 314-315 
    Details
    ISSN: 1432-1998
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Magnetic resonance imaging (MRI) is highly sensitive in detecting cerebral infarction in adults, both in the acute and chronic stages. Cytotoxic and vasogenic edema produce an increase in the water content of acutely ischemic brain, resulting in good tissue contrast from adjacent normal brain on spin density, T1 and T2 weighted MR images. Gliosis and other chronic brain changes are well seen in later stages. We recently encountered a case of remote cerebral infarction in an infant, however, which was not evident on the initial MR examination at 7 weeks of age but which was clearly seen on a follow-up scan at 9½ months. Our contention is that the infarct was masked by the known increased water content of the neonatal brain, which results in lengthened spin density and relaxation times; edema and gliosis may thus be obscured. This age-related concealment of ischemic brain changes on MR has not to our knowledge been reported, and we present this case as a caveat in the detection of cerebral infarction in neonates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02388245
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  • 7
    Electronic Resource
    Electronic Resource
    A Dynamical Systems Analysis of Semidefinite Programming with Application to Quadratic Optimization with Pure Quadratic Equality Constraints (1999)
    Springer
    Applied mathematics & optimization 40 (1999), S. 191-210 
    Details
    ISSN: 1432-0606
    Keywords: Key words. Dynamical systems, Semidefinite programming, Quadratic optimization, Quadratic equality constraints. AMS Classification. 90C26, 90C30, 58F40.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract. This paper considers the problem of minimizing a quadratic cost subject to purely quadratic equality constraints. This problem is tackled by first relating it to a standard semidefinite programming problem. The approach taken leads to a dynamical systems analysis of semidefinite programming and the formulation of a gradient descent flow which can be used to solve semidefinite programming problems. Though the reformulation of the initial problem as a semidefinite pro- gramming problem does not in general lead directly to a solution of the original problem, the initial problem is solved by using a modified flow incorporating a penalty function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002459900122
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  • 8
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    Bigger Thomas: Free at Last? (1993)
    State College, Miss. : Periodicals Archive Online (PAO)
    Mississippi Quarterly. 47:1 (1993/1994:Winter) 151 
    Details
    ISSN: 0026-637X
    Topics: English, American Studies
    Notes: ESSAY-REVIEWS
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:5220-1993-047-01-000014
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  • 9
    Electronic Resource
    Electronic Resource
    Toward time-varying balanced realization via Riccati equations (1992)
    Springer
    Mathematics of control, signals, and systems 5 (1992), S. 313-326 
    Details
    ISSN: 1435-568X
    Keywords: Balanced realization ; Time-varying systems ; Riccati equation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics , Technology
    Notes: Abstract This paper presents a new approach for solving balanced realization problems with emphasis on the time-varying case. Instead of calculating the exact solutions for balancing at each time instant, we estimate with arbitrary accuracy the balancing solutions by means of Riccati equations associated with the balancing problems Under uniform boundedness conditions on the controllability and observability grammians and their inverses, the solutions of the Riccati equations exist and converge exponentially as their initial time goes to — ∞ to give what we term μ-balancing solutions. The parameter μ has the interpretation of the gain of a differential equation. It determines the accuracy of the balancing transformation tracking and the exponential rate of convergence. Their exponentially convergent behavior ensures numerical robustness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01211564
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  • 10
    Electronic Resource
    Electronic Resource
    Influence of soil hydric parameters on the winter cold hardiness of a burrowing beetle, Leptinotarsa decemlineata (Say) (1997)
    Springer
    Journal of comparative physiology 167 (1997), S. 169-176 
    Details
    ISSN: 1432-136X
    Keywords: Key words  Cold hardiness  ;  Inoculative freezing  ;   Insect overwintering  ;  Microenvironment  ; Moisture relations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This investigation examined the influence of soil moisture and associated parameters on the cold hardiness of the Colorado potato beetle (Leptinotarsa decemlineata Say), a temperate-zone species that overwinters in terrestrial burrows. The body mass and water content of adult beetles kept in sand at 4 °C varied over a 16-week period of diapause according to the substratum's moisture content. Changes in body water content, in turn, influenced the crystallization temperature (range −3.3 to −18.4 °C; n = 417), indicating that environmental moisture indirectly determined supercooling capacity, a measure of physiological cold hardiness. Beetles held in dry sand readily tolerated a 24-h exposure to temperatures ranging from 0° to −5 °C, but those chilled in sand containing as little as 1.7% water (dry mass) had elevated mortality. Thus, burrowing in dry soils not only promotes supercooling via its effect on water balance, but may also inhibit inoculative freezing. Mortality of beetles exposed to −5 °C for 24 h was lower in substrates composed of sand, clay and/or peat (36–52%) than in pure silica sand (78%) having an identical water content (17.0% dry mass). In addition to moisture, the texture, structure, water potential, and other physico-chemical attributes of soil may strongly influence the cold hardiness and overwintering survival of burrowing insects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003600050061
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