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open access

Manufacturing diamond films using copper vapour lasers

Description: Fifty nanosecond pulses of visible light have been used to produce hard, hydrogen-free diamond-like-carbon (DLC) films at irradiances between 5 x 10{sup 8} and 5 x 10{sup 10} W/cm{sup 2} The films were characterized by a number of techniques including: Raman spectroscopy, Electron Energy Loss Spectroscopy (EELS), atomic force microscopy, and spectroscopic ellipsometry. The cost for manufacturing DLC with high average power, high-pulse repetition frequency, visible light is low enough to compete… more
Date: January 8, 1996
Creator: McLean, M., LLNL
Partner: UNT Libraries Government Documents Department
open access

Simulations of Laser Imprint for Nova Experiments and for Ignition Capsules

Description: In direct drive ICF, nonuniformities in laser illumination seed ripples at the ablation front in a process called imprint. These non nonuniformities grow during the capsule implosion and, if initially large enough, can penetrate the capsule shell, impede ignition, or degrade burn. Imprint has been simulated for recent experiments performed on the Nova laser at LLNL examining a variety of beam smoothing conditions. Most used laser intensities similar to the early part of an ignition capsule puls… more
Date: November 8, 1996
Creator: Weber, S. V.; Glendinning, S. G.; Kalantar, D. H.; Key, M. H.; Remington, B. A.; Rothenberg, J. E. et al.
Partner: UNT Libraries Government Documents Department
open access

Analysis of losses in ITER joints in varying parallel field

Description: One of the options for a design of a Central Solenoid in ITER and other tokamak machines is pancake would modules. In this configuration joints have to be placed in maximum magnetic field with high changing rate. In this condition joints should be designed to have at least the same or larger temperature margin as that for the conductor in the same field. It is argued that joints in parallel field can be designed to meet this requirement along with reasonably low DC resistance. Losses in paralle… more
Date: August 8, 1996
Creator: Martovetsky, N. N.
Partner: UNT Libraries Government Documents Department
open access

Landscape paradigms in physics and biology: Introduction and overview

Description: A brief introductory overview in general terms is given of concepts, issues and applications of the paradigm of rugged landscapes in the contexts of physics and biology.
Date: July 8, 1996
Creator: Sherrington, D.
Partner: UNT Libraries Government Documents Department
open access

Charge-density wave and magnetic phase diagram of chromium alloys

Description: The magnetic phase diagrams of all dilute Cr alloys can be explained by a simple theoretical model with coupled spin- and charge-density waves and a finite electron reservoir. If the charge-density wave and electron reservoir are sufficiently large, the paramagnetic to commensurate spin-density wave transition becomes strongly first order, as found in Cr{sub 1- x}Fe{sub x} and Cr{sub 1-x}Si{sub x} alloys. The observed discontinuity of the slope dT{sub N}/dx at the triple point and the bending o… more
Date: August 8, 1996
Creator: Fishman, R.S. & Jiang, X.W.
Partner: UNT Libraries Government Documents Department
open access

Thomson scattering in the corona of laser-produced gold plasmas

Description: Thomson scattering measurements of the electron temperature in laser- produced gold plasmas are presented. We irradiated a flat gold disk target with one laser beam of the Nova laser facility. A second laser beam probed the plasma at a distance of 500{mu}m with temporally resolved Thomson scattering. The electron temperature measurements are compared with hydrodynamic simulations using the code LASNEX for experiments applying smoothed and unsmoothed heater beams. In case of an unsmoothed heater… more
Date: May 8, 1996
Creator: Glenzer, S. H.; Back, C. A.; Estabrook, K. G. & MacGowan, B. J.
Partner: UNT Libraries Government Documents Department
open access

Molecular dynamics modeling of microstructure evolution during growth of amorphous carbon films

Description: Amorphous carbon films approximately 20 nm thick are used throughout the computer industry as protective coatings on magnetic storage disks. As storage densities increase, the role of the overcoat becomes increasingly important because of smaller spacings between the recording head and the spinning disk. Furthermore, future-generation disks call for an overcoat thickness of 5 nm or less. These small length scales and the high speed of the spinning disk (10-30 m/s) suggest that a molecular dynam… more
Date: January 8, 1996
Creator: Glosli, J.N.; Belak, J. & Philpott, M.R.
Partner: UNT Libraries Government Documents Department
open access

100 Femtosecond laser absorption in solid density targets

Description: Experimental short pulse lasers are rapidly approaching energy levels where target irradiances exceeding 10{sup 20} W/CM{sup 2} are routinely achievable. These high intensity levels will open up a new class of solid target interaction physics where relativistic effects must be included and non-traditional absorption mechanisms become significant. However much remains to be understood of the absorption physics at lower intensities where classical absorption is dominated by collisional and resona… more
Date: October 8, 1996
Creator: Price, D. F.; More, R. M.; Walling, R. S. & Stewart, R. E.
Partner: UNT Libraries Government Documents Department
open access

Conceptual design for a user-friendly adaptive optics system at Lick Observatory

Description: In this paper, we present a conceptual design for a general-purpose adaptive optics system, usable with all Cassegrain facility instruments on the 3 meter Shane telescope at the University of California`s Lick Observatory located on Mt. Hamilton near San Jose, California. The overall design goal for this system is to take the sodium-layer laser guide star adaptive optics technology out of the demonstration stage and to build a user-friendly astronomical tool. The emphasis will be on ease of cal… more
Date: March 8, 1996
Creator: Bissinger, H.D.; Olivier, S. & Max, C.
Partner: UNT Libraries Government Documents Department
open access

Information, complexity and efficiency: The automobile model

Description: The new, rapidly evolving field of industrial ecology - the objective, multidisciplinary study of industrial and economic systems and their linkages with fundamental natural systems - provides strong ground for believing that a more environmentally and economically efficient economy will be more information intensive and complex. Information and intellectual capital will be substituted for the more traditional inputs of materials and energy in producing a desirable, yet sustainable, quality of … more
Date: August 8, 1996
Creator: Allenby, B.
Partner: UNT Libraries Government Documents Department
open access

Performance of keck adaptive optics with sodium laser guide star

Description: The Keck telescope adaptive optics system is designed to optimize performance in he 1 to 3 micron region of observation wavelengths (J, H, and K astronomical bands). The system uses a 249 degree of freedom deformable mirror, so that the interactuator spacing is 56 cm as mapped onto the 10 meter aperture. 56 cm is roughly equal to r0 at 1.4 microns, which implies the wavefront fitting error is 0.52 ({lambda}/2{pi})({ital d}/{ital r}{sub 0}){sup 5/6} = 118 nm rms. This is sufficient to produce a … more
Date: March 8, 1996
Creator: Gavel, D. T.; Olivier, S. & Brase, J.
Partner: UNT Libraries Government Documents Department
open access

Nondestructive inspection of organic films on sandblasted metals using diffuse reflectance infrared spectroscopy

Description: Diffuse reflectance infrared spectroscopy is a very useful tool for the determination of surface contamination and characterization of films in manufacturing applications. Spectral data from the surfaces of a host of practical materials may be obtained with sufficient insensitivity to characterize relatively thick films, such as paint, and the potential exists to detect very thin films, such as trace oil contamination on metals. The SOC 400 Surface Inspection Machine/InfraRed (SIMIR) has been d… more
Date: July 8, 1996
Creator: Powell, G. L.; Cox, R. L.; Barber, T. E. & Neu, J. T.
Partner: UNT Libraries Government Documents Department
open access

Gist: A scientific graphics package for Python

Description: {open_quotes}Gist{close_quotes} is a scientific graphics library written by David H. Munro of Lawrence Livermore National Laboratory (LLNL). It features support for three common graphics output devices: X Windows, (Color) PostScript, and ANSI/ISO Standard Computer Graphics Metafiles (CGM). The library is small (written directly to Xlib), portable, efficient, and full-featured. It produces X versus Y plots with {open_quotes}good{close_quotes} tick marks and tick labels, 2-dimensional quadrilater… more
Date: May 8, 1996
Creator: Busby, L.E.
Partner: UNT Libraries Government Documents Department
open access

Evaluation of concrete masonry unit walls for lateral natural phenomena hazards loads

Description: Older single-story facilities (Pre-1985 vintage) are commonly constructed of structural steel framing with concrete masonry unit (CMU) walls connected to columns and roof girders of the steel framing system. The CMU walls are designed for lateral wind and seismic loads (perpendicular to the wall) and transmit shear loads from the roof diaphragm to the foundation footings. The lateral loads normally govern their design. The structural framing system and the roof diaphragm system are straight for… more
Date: March 8, 1996
Creator: Faires, W.E. Jr.
Partner: UNT Libraries Government Documents Department
open access

Introduction to chiral symmetry

Description: These lectures are an attempt to a pedagogical introduction into the elementary concepts of chiral symmetry in nuclear physics. Effective chiral models such as the linear and nonlinear sigma model will be discussed as well as the essential ideas of chiral perturbation theory. Some applications to the physics of ultrarelativistic heavy ion collisions will be presented.
Date: January 8, 1996
Creator: Koch, V.
Partner: UNT Libraries Government Documents Department
open access

Keck adaptive optics: control subsystem

Description: Adaptive optics on the Keck 10 meter telescope will provide an unprecedented level of capability in high resolution ground based astronomical imaging. The system is designed to provide near diffraction limited imaging performance with Strehl {gt} 0.3 n median Keck seeing of r0 = 25 cm, T =10 msec at 500 nm wavelength. The system will be equipped with a 20 watt sodium laser guide star to provide nearly full sky coverage. The wavefront control subsystem is responsible for wavefront sensing and th… more
Date: March 8, 1996
Creator: Brase, J.M.; An, J. & Avicola, K.
Partner: UNT Libraries Government Documents Department
open access

The heavy top quark and supersymmetry

Description: Three aspects of supersymmetric theories are discussed: electroweak symmetry breaking, the issues of flavor, and gauge unification. The heavy top quark plays an important, sometimes dominant, role in each case. Additional symmetries lead to extensions of the standard model which can provide an understanding for many of the outstanding problems of particle physics. A broken supersymmetric extension of spacetime allows electroweak symmetry breaking to follow from the dynamics of the heavy top qua… more
Date: May 8, 1996
Creator: Hall, L.J.
Partner: UNT Libraries Government Documents Department
open access

U.S./Russian lab-to-lab materials protection, control and accounting program efforts at the Institute of Inorganic Materials

Description: The All-Russian Scientific Research Institute of Inorganic Materials (VNIINM) performs research in nuclear power reactor fuel,m spent fuel reprocessing and waste management, materials science of fissionable and reactor structural materials, metallurgy, superconducting materials, and analytical sciences. VNIINM supports the Ministry of Atomic Energy of the Russian Federation (MINATOM) in technologies for fabrication and processing of nuclear fuel. As a participant in the U. S./Russian Lab-to-Lab… more
Date: July 8, 1996
Creator: Ruhter, W. D.; Kositsyn, V.; Rudenko, V.; Siskind, B.; Bieber, A.; Hoida, H. et al.
Partner: UNT Libraries Government Documents Department
open access

GAMMA IRRADIATION TESTING OF MONTAN WAX FOR USE IN WASTE MANAGEMENT SYSTEMS

Description: A field demonstration was funded by the US Department of Energy (DOE) to quantify the potential use of montan wax as a subsurface barrier material for nuclear waste management applications. As part of that demonstration, a study was completed to address some of the characteristics of the wax. Of particular interest is its resistance to chemical and structural changes that would influence its integrity as a barrier to minimize the migration of contaminants from their storage or disposal location… more
Date: September 8, 1996
Creator: Soo, P.; Heiser, J. & Hart, A.
Partner: UNT Libraries Government Documents Department
open access

Possible evidence for orbital magnetism below the superconducting transition temperature in UBe{sub 12.91}B{sub 0.09}

Description: Although the unconventional nature of the superconductivity in pure and doped UBe{sub 13} has been well established, the precise nature of the superconducting order parameter is still unknown. The authors present muon spin rotation measurements in boron-doped UBe{sub 13} showing a paramagnetic frequency shift below the superconducting transition temperature which is nearly independent of applied magnetic field (0.01--0.10 T), unlike a conventional Knight shift. No increase in linewidth is obser… more
Date: July 8, 1996
Creator: Heffner, R. H.; Le, L. P.; Nieuwenhuys, G. J.; MacLaughlin, D. E.; Amato, A.; Gygax, F. N. et al.
Partner: UNT Libraries Government Documents Department
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