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Design and performance of the Beamlet laser third harmonic frequency converter

Description: The Beamlet laser is a full-scale, single-aperture scientific prototype of the frequency-tripled Nd:glass laser for the proposed National Ignition Facility. At aperture sizes of 30 cm x 30 cm and 34 cm x 34 cm using potassium dihydrogen phosphate crystals of 32 cm x 32 cm and 37 cm x 37 cm, respectively, the authors have obtained up to 8.3 kJ of third harmonic energy at 70%--80% whole beam conversion efficiency.
Date: September 12, 1995
Creator: Barker, C. E.; van Wonterghem, B. M.; Auerbach, J. M.; Foley, R. J.; Murray, J. R.; Campbell, J. H. et al.
Partner: UNT Libraries Government Documents Department
open access

T{bar t} kinematics in W+ {ge} 3 Jet events

Description: The objective of this talk is to compare the CDF W+ {ge} 3 Jets data with Monte Carlo predictions using the standard model with the top quark. The data is seen to be consistent with these predictions using the t{bar t} production rate indicated by the SVX b-tagging and the previously reported top mass.
Date: July 12, 1995
Creator: Binkley, M.
Partner: UNT Libraries Government Documents Department
open access

Sodium carbonate salt transport system

Description: A sodium carbonate salt transport system is required to support the Molten Salt Oxidation system being constructed at Lawrence Livermore National Laboratory. We are embarking on a project to create a national test bed for evaluating mixed waste destruction technologies. This project is called the Mixed Waste Management Facility. It is currently in the second phase of design and will be operational in 1998. One of the first technologies demonstrated in this facility is Molten Salt Oxidation. Mol… more
Date: September 12, 1995
Creator: Brummond, W.
Partner: UNT Libraries Government Documents Department
open access

Porous networks derived from synthetic polymer-clay complexes

Description: Synthetic hectorites were hydrothermally crystallized with direct incorporation of a cationic polymer poly(dimethyl diallyl ammonium chloride) (PDDA), and two neutral cellulosic polymers hydroxypropyl methylcellulose (HPMC) and hydroxyethyl cellulose (HEC). Synthetic PDDA-hectorite displays the lowest d-spacing at 15.8 {Angstrom} along with less polymer incorporation (7.8 wt % organic) than the neutral polymers (18--22 wt % organic). Thermal analysis and small angle neutron scattering were used… more
Date: May 12, 1995
Creator: Carrado, K. A.; Thiyagarajan, P. & Elder, D. L.
Partner: UNT Libraries Government Documents Department
open access

Laser plasma diagnostics of dense plasmas

Description: The authors describe several experiments on Nova that use laser-produced plasmas to generate x-rays capable of backlighting dense, cold plasmas (p {approximately} 1--3 gm/cm{sup 3}, kT {approximately} 5--10 eV, and areal density {rho}{ell}{approximately} 0.01--0.05 g/cm{sup 2}). The x-rays used vary over a wide range of h{nu}, from 80 eV (X-ray laser) to 9 keV. This allows probing of plasmas relevant to many hydrodynamic experiments. Typical diagnostics are 100 ps pinhole framing cameras for a … more
Date: July 12, 1995
Creator: Glendinning, S. G.; Amendt, P.; Budil, K. S.; Hammel, B. A.; Kalantar, D. H.; Key, M. H. et al.
Partner: UNT Libraries Government Documents Department
open access

Shock Wave Measurements

Description: Much of our knowledge of the properties of matter at high pressures, from the static ruby pressure scale to shock compression at Gbar pressures, rests ultimately on the use of shock waves. Simple conservation relations define the initial and final states, leading to absolute measurements. I will describe some methods for measuring the equation of state of materials under shock loading for a variety of methods of shock production, and also describe the basis for other optical methods used widely… more
Date: September 12, 1995
Creator: Holmes, Neil C.
Partner: UNT Libraries Government Documents Department
open access

Mesoscale Modeling of the Inland Nocturnal Sea Breeze

Description: The mesoscale sea breeze has important consequences for many densely populated coastal environments, including convection initiation, aviation safety, and air quality. The sea breeze characteristics before and after sunset are markedly different (Sha et al 1993). A gravity current will form during the early afternoon due to the relatively large density difference between the land and sea air. During the afternoon, as the lighter land air is forced upward by the cooler dense sea air, Kelvin-Helm… more
Date: September 12, 1995
Creator: Kurzeja, R. J. & Buckley, R. L.
Partner: UNT Libraries Government Documents Department
open access

ICF burn-history measurments using 17-MeV fusion gamma rays

Description: Fusion reaction rate for inertial-confinement fusion (ICF) experiments at the Nova Laser Facility is measured with 30-ps resolution using a high-speed neutron detector. We are investigating a measurement technique based on the 16.7-MeV gamma rays that are released in deuterium-tritium fusion. Our concept is to convert gamma-ray energy into a fast burst of Cerenkov light that can be recorded with a high-speed optical detector. We have detected fusion gamma rays in preliminary experiments conduct… more
Date: April 12, 1995
Creator: Lerche, R. A.; Cable, M. D. & Dendooven, P. G.
Partner: UNT Libraries Government Documents Department
open access

Modeling the dynamic crush of impact mitigating materials

Description: Crushable materials are commonly utilized in the design of structural components to absorb energy and mitigate shock during the dynamic impact of a complex structure, such as an automobile chassis or drum-type shipping container. The development and application of several finite-element material models which have been developed at various times at LLNL for DYNA3D will be discussed. Between the models, they are able to account for several of the predominant mechanisms which typically influence t… more
Date: May 12, 1995
Creator: Logan, R.W. & McMichael, L.D.
Partner: UNT Libraries Government Documents Department
open access

Electromagnetic and thermal analysis of distributed cooled high power millimeter wave windows

Description: The sectional high-frequency internally-cooled window, as proposed by General Atomics, has unique potential for allowing microwave sources to reach multi-megawatt CW levels with application to ECRH. Designs are being investigated using computational electromagnetic (EM), thermal, and mechanical codes at 110 GHz and 170 GHz to examine the design tradeoffs between RF performance and thermal mechanical safety margins. The EM analyses are for the window, under vacuum at one MW and includes variatio… more
Date: May 12, 1995
Creator: Nelson, S. D.; Reitter, T. & Caplan, M.
Partner: UNT Libraries Government Documents Department
open access

Simulation of multicomponent losses in electron beam melting and refining at varying scan frequencies

Description: A two-stage model is presented to describe alloy element evaporation rates from molten metal due to transient local heating by an electron beam. The first stage is a simulation of transient phenomena near the melt surface due to periodic heating by a scanning beam, the output of which is the relationship between operating parameters, surface temperature, and evaporation rate. At high scan rates, this can be done using a simple one-dimensional heat transfer model of the surface layer; at lower s… more
Date: October 12, 1995
Creator: Powell, A.; Szekely, J.; Van Den Avyle, J. & Damkroger, B.
Partner: UNT Libraries Government Documents Department
open access

2D and 3D ablation front hydrodynamic instability experiments on Nova

Description: Single-mode experiments have been conducted on the Nova laser to examine the effect of perturbation shape on ablation front Rayleigh-Taylor growth. The perturbations investigated had the same magnitude wave vector k=(k{sub x}{sup 2}+k{sub y}{sup 2}){sup 1/2} and the same initial amplitude. The shapes corresponded to 2D {lambda}=50 {mu}m, 3D square k{sub x}=k{sub y}, and stretched k{sub x}=3k{sub y} perturbations. We observed that the 3D perturbations grew more than the 2D perturbation. Numerica… more
Date: April 12, 1995
Creator: Remington, B. A.; Marinak, M. M. & Weber, S. V.
Partner: UNT Libraries Government Documents Department
open access

Workshop in computational molecular biology, April 15, 1991--April 14, 1994

Description: Funds from this award were used to the Workshop in Computational Molecular Biology, `91 Symposium entitled Interface: Computing Science and Statistics, Seattle, Washington, April 21, 1991; the Workshop in Statistical Issues in Molecular Biology held at Stanford, California, August 8, 1993; and the Session on Population Genetics a part of the 56th Annual Meeting, Institute of Mathematical Statistics, San Francisco, California, August 9, 1993.
Date: April 12, 1995
Creator: Tavare, S.
Partner: UNT Libraries Government Documents Department
open access

CONTAIN code analyses of direct containment heating (DCH) experiments: Model assessment and phenomenological interpretation

Description: Models for direct containment heating (DCH) in the CONTAIN code for severe accident analysis have been reviewed and a standard input prescription for their use has been defined. The code has been exercised against a large subset of the available DCH data base. Generally good agreement with the experimental results for containment pressurization ({Delta}P) and hydrogen generation has been obtained. Extensive sensitivity studies have been performed which permit assessment of many of the strengths… more
Date: May 12, 1995
Creator: Williams, D. C.; Griffith, R. O.; Tadios, E. L. & Washington, K. E.
Partner: UNT Libraries Government Documents Department
open access

A database of wavefront measurements for laser system modeling, optical component development and fabrication process qualification

Description: In the second half of the 1990`s, LLNL and others anticipate designing and beginning construction of the National Ignition Facility (NIF). The NIF will be capable of producing the worlds first laboratory scale fusion ignition and bum reaction by imploding a small target. The NIF will utilize approximately 192 simultaneous laser beams for this purpose. The laser will be capable of producing a shaped energy pulse of at least 1.8 million joules (MJ) with peak power of at least 500 trillion watts (… more
Date: April 12, 1995
Creator: Wolfe, C. R.; Lawson, J. K.; Aikens, D. M. & English, R. E.
Partner: UNT Libraries Government Documents Department
open access

Measurement of wavefront structure from large aperture optical components by phase shifting interferometry

Description: This paper discusses the results of high spatial resolution measurement of the transmitted or reflected wavefront of optical components using phase shifting interferometry with a wavelength of 6328 {angstrom}. The optical components studied range in size from approximately 50 mm {times} 100 mm to 400 mm {times} 750 mm. Wavefront data, in the form of 3-D phase maps, have been obtained for three regimes of scale length: ``micro roughness``, ``mid-spatial scale``, and ``optical figure/curvature.``… more
Date: May 12, 1995
Creator: Wolfe, C. R.; Lawson, J. K.; Kellam, M.; Maney, R. T. & Demiris, A.
Partner: UNT Libraries Government Documents Department
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