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Developing solid state experiments on the Nova laser (open access)

Developing solid state experiments on the Nova laser

An x-ray drive has been developed to shock compress metal foils in the solid state using an internally shielded hohlraum with a high contrast shaped pulse from the Nova laser. The drive has been characterized and hydrodynamics experiments designed to study growth of the Rayleigh-Taylor (RT) instability in Cu foils at 3 Mbar peak pressures in the plastic flow regime have been started. Pre-imposed modulations with an initial wavelength of 20-50 {micro}m, and amplitudes of 1.0-2.5 {micro}m show growth consistent with simulations. In the Nova experiments, the fluid and solid states are expected to behave similarly for Cu. An analytic stability analysis is used to motivate an experimental design with an Al foil where the effects of material strength on the RT growth are significantly enhanced. The conditions reached in the metal foils at peak compression are similar to those predicted at the core of the earth.
Date: August 6, 1999
Creator: Chandler, E. A.; Colvin, J. D.; Failor, B. H.; Gold, D. M.; Hauer, A.; Kalantar, D. H. et al.
System: The UNT Digital Library
Grain boundaries and mechanical properties of nanocrystalline diamond films. (open access)

Grain boundaries and mechanical properties of nanocrystalline diamond films.

Phase-pure nanocrystalline diamond thin films grown from plasmas of a hydrogen-poor carbon argon gas mixture have been analyzed regarding their hardness and elastic moduli by means of a microindentor and a scanning acoustic microscope.The films are superhard and the moduli rival single crystal diamond. In addition, Raman spectroscopy with an excitation wavelength of 1064 nm shows a peak at 1438 l/cm and no peak above 1500 l/cm, and X-ray photoelectron spectroscopy a shake-up loss at 4.2 eV. This gives strong evidence for the existence of solitary double bonds in the films. The hardness and elasticity of the films then are explained by the assumption, that the solitary double bonds interconnect the nanocrystals in the films, leading to an intergrain boundary adhesion of similar strength as the intragrain diamond cohesion. The results are in good agreement with recent simulations of high-energy grain boundaries.
Date: August 6, 1999
Creator: Busmann, H.-G.; Pageler, A. & Gruen, D. M.
System: The UNT Digital Library
Low-Level Radioactive Waste Management at the Nevada Test Site - Year 2000 Current Status (open access)

Low-Level Radioactive Waste Management at the Nevada Test Site - Year 2000 Current Status

The performance objectives of the Department of Energy's Low-level radioactive waste disposal facilities at the Nevada Test Site transcend those of any other radioactive waste disposal site in the United States. The expanded paper will describe the technical attributes of the facilities, the present and the future disposal capacities and capabilities, and includes a description of the process from waste approval to final disposition. The paper also summarizes the current status of the waste disposal operations.
Date: August 6, 1999
Creator: Bruce D. Becker, Bechtel Nevada; Bruce M. Crowe, Los Alamos National Laboratory; Carl P. Gertz, DOE Nevada & Wendy A. Clayton, DOE Nevada
System: The UNT Digital Library
The National Facility physics and diagnostics (open access)

The National Facility physics and diagnostics

This paper presents a description of the National Ignition Facility, some of the physics experiments that will be performed on it and a description of some of the diagnostics needed to complete these experiments. Experiments are presented under the headings of: ignition physics, weapons physics or high-energy-density experimental science, weapons effects, and basic science and inertial fusion energy. The diagnostics discussed are primarily those that will be provided for early operation.
Date: August 6, 1999
Creator: Wooton, A
System: The UNT Digital Library
The national facility physics and diagnostics (open access)

The national facility physics and diagnostics

This paper presents a description of the National Ignition Facility, some of the physics experiments that will be performed on it and a description of some of the diagnostics needed to complete these experiments. Experiments are presented under the headings of: ignition physics, weapons physics or high-energy-density experimental science, weapons effects, and basic science and inertial fusion energy. The diagnostics discussed are primarily those that will be provided for early operation.
Date: August 6, 1999
Creator: Wootton, A
System: The UNT Digital Library
The National Facility physics and diagnostics (open access)

The National Facility physics and diagnostics

This paper presents a description of the National Ignition Facility, some of the physics experiments that will be performed on it, and a description of some of the diagnostics needed to complete these experiments. Experiments are presented under the headings of: ignition physics, weapons physics or high-energy-density experimental science, weapons effects, and basic science and inertial fusion energy. The diagnostics discussed are primarily those that will be provided for early operation.
Date: August 6, 1999
Creator: Wootton, A.
System: The UNT Digital Library
The national wildfire prediction program: a key piece of the wildfire solution (open access)

The national wildfire prediction program: a key piece of the wildfire solution

Lawrence Livermore National Laboratory and Los Alamos National Laboratory have developed an initiative for a National Wildfire Prediction Program. The program provides guidance for fire managers throughout the country, assisting them to efficiently use limited fire-fighting resources. To achieve maximum cost leveraging, the program builds upon existing physics-based atmospheric and wildfire modeling efforts, a proven emergency response infrastructure, state-of-the-art computer science, and the world's most advanced supercomputers to create a comprehensive wildfire prediction system.
Date: August 6, 1999
Creator: Bossert, J E; Bradley, M M; Hanson, H P; Schomer, C L & Sumikawa, D A
System: The UNT Digital Library
PROSPECT: A Computer System for Globally-Optimal Threading (open access)

PROSPECT: A Computer System for Globally-Optimal Threading

This paper presents a new computer system, PROSPECT, for protein threading. PROSPECT employs an energy function that consists of three additive terms: (1) a singleton fitness term, (2) a distance-dependent pairwise-interaction preference term, and (3) alignment gap penalty; and currently uses FSSP as its threading template database. PROSPECT uses a divide-and-conquer algorithm to find an alignment between a query protein sequence and a protein fold template, which is guaranteed to be globally optimal for its energy function. The threading algorithm presented here significantly improves the computational efficiency of our previously-published algorithm, which makes PROSPECT a practical tool even for large protein threading problems. Mathematically, PROSPECT finds a globally-optimal threading between a query sequence of n residues and a fold template of m residues and M core secondary structures in O(nm + MnN{sup 1.5C{minus}1}) time and O(nm + nN{sup C{minus}1}) space, where C, the topological complexity of the template fold as we term, is a value which characterizes the overall structure of the considered pairwise interactions in the fold; and N represents the maximum number of possible alignments between an individual core of the fold and the query sequence when its neighboring cores are already aligned. PROSPECT allows a user to …
Date: August 6, 1999
Creator: Xu, D. & Xu, Y.
System: The UNT Digital Library
Slim Holes for Small Power Plants (open access)

Slim Holes for Small Power Plants

Geothermal research study at Sandia National Laboratories has conducted a program in slimhole drilling research since 1992. Although our original interest focused on slim holes as an exploration method, it has also become apparent that they have substantial potential for driving small-scale, off-grid power plants. This paper summarizes Sandia's slim-hole research program, describes technology used in a ''typical'' slimhole drilling project, presents an evaluation of using slim holes for small power plants, and lists some of the research topics that deserve further investigation.
Date: August 6, 1999
Creator: Finger, John T.
System: The UNT Digital Library
Structural and magnetic properties of UCo{sub 1/3}T{sub 2/3}Al solid solutions (T = Ru, Pt, Rh). (open access)

Structural and magnetic properties of UCo{sub 1/3}T{sub 2/3}Al solid solutions (T = Ru, Pt, Rh).

We report on neutron diffraction studies of UCo{sub 1/3}T{sub 2/3}Al (T = Ru, Pt, Rh). All three solid solutions form in the hexagonal ZrNiAl structure. The Ru-containing compound is found to be chemically ordered, while the Pt-containing compound is nearly disordered and the Rh-containing compound is purely disordered. All three compounds exhibit long-range magnetic order with rather small U moments.
Date: August 6, 1999
Creator: Andreev, A. V.; Bordallo, H. N.; Chang, S.; Nakotte, H.; Schultz, A. J.; Sechovsky, V. et al.
System: The UNT Digital Library