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Micrometer-Scale Machining of Metals and Polymers Enabled by Focused Ion Beam Sputtering

Description: This work combines focused ion beam sputtering and ultra-precision machining for microfabrication of metal alloys and polymers. Specifically, micro-end mills are made by Ga ion beam sputtering of a cylindrical tool shank. Using an ion energy of 20keV, the focused beam defines the tool cutting edges that have submicrometer radii of curvature. We demonstrate 25 {micro}m diameter micromilling tools having 2, 4 and 5 cutting edges. These tools fabricate fine channels, 26-28 microns wide, in 6061 al… more
Date: December 22, 1998
Creator: Adams, D.P.; Benavides, G.L. & Vasile, M.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Generating High-Brightness Light Ion Beams for Inertial Fusion Energy

Description: Light ion beams may be the best option for an Inertial Fusion Energy (IFE) driver from the standpoint of ei%ciency, standoff, rep-rate operation and cost. This approach uses high-energy-density pulsed power to efficiently accelerate ions in one or two stages at fields of 0.5 to 1.0 GV/m to produce a medium energy (30 MeV), high-current (1 MA) beam of light ions, such as lithium. Ion beams provide the ability for medium distance transport (4 m) of the ions to the target, and standofl of the driv… more
Date: October 22, 1998
Creator: Adams, R. G.; Bailey, J. E.; Cuneno, M. E.; Desjarlais, M. P.; Filuk, A. B.; Hanson, D. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Development, field testing of a laser instrument for the measurement of sediment reference concentration in the MARGINS Program. Final report

Description: A small grant was added to an ongoing Navy program to extend the scope of ongoing work by development of a new laser instrument. The instrument, MSCAT (Miniature Scattering and Transmissometry) uses small angle scattering to obtain the needed multi-parameter information for measurement of particle size distribution and number density. During the short course of the grant, the instrument was built and tested in a field experiment off the coast of North Carolina. Useful data were obtained, and th… more
Date: May 22, 1998
Creator: Agrawal, Yogesh C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Project W-320, 241-C-106 sluicing: Civil/structural calculations. Volume 2

Description: This supporting document has been prepared to make the FDNW calculations for Project W-320 readily retrievable. The Equipment Removal System (ERS) has been identified by WHC as not having any safety class 1 items present in the tank pits during equipment removal activities. Documentation of this finding is provided in Letter of Instruction 3/1 Analysis Requirements for Project W-320 Equipment Removal System (REF: LOI KGS-94-013). Based on this specific direction from WHC, 3/1 analysis for any c… more
Date: July 22, 1998
Creator: Bailey, J. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Visualization of scalar topology for structural enhancement

Description: Scalar fields arise in every scientific application. Existing scalar visualization techniques require that the user infer the global scalar structure from what is frequently an insufficient display of information. We present a visualization technique which numerically detects the structure at all scales, removing from the user the responsibility of extracting information implicit in the data, and presenting the structure explicitly for analysis. We further demonstrate how scalar topology detect… more
Date: September 22, 1998
Creator: Bajaj, C. L.; Pascucci, V. & Schikore, D. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Hypervolume visualization: a challenge in simplicity

Description: Hyper-volume visualization is designed to provide simple and fully explanatory images that give comprehensive insights into the global structure of scalar fields of any dimension. The basic idea is to have a dimension independent viewing system that scales nicely with the geometric dimension of the dataset and that can be combined with classical approaches like isocontouring and animation of slices of <i>n</i>.D data. We completely abandon (for core simplicity) rendering techniques,… more
Date: September 22, 1998
Creator: Bajaj, C. L.; Pascucci, V.; Rabbiolo, G. & Schikore, D. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Enhanced adhesion for LIGA microfabrication by using a buffer layer

Description: The present invention is an improvement on the LIGA microfabrication process wherein a buffer layer is applied to the upper or working surface of a substrate prior to the placement of a resist onto the surface of the substrate. The buffer layer is made from an inert low-Z material (low atomic weight), a material that absorbs secondary X-rays emissions from the substrate that are generated from the substrate upon exposure to a primary X-rays source. Suitable materials for the buffer layer includ… more
Date: May 22, 1998
Creator: Bajikar, Sateesh S.; DeCarlo, Francesco & Song, Joshua J.
Item Type: Refine your search to only Patent
Partner: UNT Libraries Government Documents Department
open access

Optimizations for parallel object oriented frameworks

Description: Application codes reliably under perform the advertised performance of existing architectures, compilers have only limited mechanisms with which to effect sophisticated transformations to arrest this trend. Compilers are forced to work within the broad semantics of the complete language specification and thus can not guarantee correctness of more sophisticated transformations. Object-oriented frameworks provide a level of tailoring of the C++ language to specific, albeit often restricted contex… more
Date: September 22, 1998
Creator: Basetti, F; Davis, K & Quinlan, D
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effects of Wet Etch Processing on Laser-Induced Damage of Fused Silica Surfaces

Description: Laser-induced damage of transparent fused silica optical components by 355 nm illumination occurs primarily at surface defects produced during the grinding and polishing processes. These defects can either be surface defects or sub-surface damage.Wet etch processing in a buffered hydrogen fluoride (HF) solution has been examined as a tool for characterizing such defects. A study was conducted to understand the effects of etch depth on the damage threshold of fused silica substrates. The study u… more
Date: December 22, 1998
Creator: Battersby, C. L.; Kozlowski, M. R. & Sheehan, L. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Automated damage test facilities for materials development and production optic quality assurance at Lawrence Livermore National Laboratory

Description: The Laser Program at LLNL has developed automated facilities for damage testing optics up to 1 meter in diameter. The systems were developed to characterize the statistical distribution of localized damage performance across large-aperture National Ignition Facility optics. Full aperture testing is a key component of the quality assurance program for several of the optical components. The primary damage testing methods used are R:1 mapping and raster scanning. Automation of these test methods w… more
Date: December 22, 1998
Creator: Battersby, C.; Dickson, R.; Jennings, R.; Kimmons, J.; Kozlowski, M. R.; Maricle, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Polymer pendant crown thioethers for removal of mercury from acidic wastes

Description: Removal and immobilization of mercury ions from industrial waste streams is a difficult and expensive problem requiring an efficient and selective extractant that is resistant to corrosive conditions. We have now developed an acid-resistant thiacrown polymer that has potential utility as a selective and cost-effective Hg<sup>2+</sup> extractant. Copolymerization of a novel C-substituted thiacrown, N,N-(4-vinylbenzylmethyl)-2-aminomethyl- ,4,&l 1,14- pentathiacycloheptadecane, with DVB (80% divi… more
Date: December 22, 1998
Creator: Baumann, T F; Fox, G A & Reynolds, J
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Coulomb clusters in RETRAP

Description: Storage rings and Penning traps are being used to study ions in their highest charge states. Both devices must have the capability for ion cooling in order to perform high precision measurements such as mass spectrometry and laser spectroscopy. This is accomplished in storage rings in a merged beam arrangement where a cold electron beam moves at the speed of the ions. In RETRAP, a Penning trap located at Lawrence Livermore National Laboratory, a sympathetic laser/ion cooling scheme has been imp… more
Date: October 22, 1998
Creator: Beck, B. R.; Church, D. A.; Gruber, L.; Holder, J. P.; Schneider, D. & Steiger, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Highly charged ion trapping and cooling

Description: In the past few years a cryogenic Penning trap (RETRAP) has been operational at the Electron Beam Ion Trap (EBIT) facility at Lawrence Livermore National Laboratory. The combination of RETRAP and EBIT provides a unique possibility of producing and re-trapping highly charged ions and cooling them to very low temperatures. Due to the high Coulomb potentials in such an ensemble of cold highly charged ions the Coulomb coupling parameter (the ratio of Coulomb potential to the thermal energy) can eas… more
Date: October 22, 1998
Creator: Beck, B. R.; Church, D. A.; Gruber, L.; Holder, J. P.; Schneider, D. & Steiger, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

First principles calculations for litiated manganese oxides

Description: First principles calculations using the local-spin-density-functional theory are presented of densities of electronic states for MnO, LiMnO{sub 2} in the monoclinic and orthorhombic structures, cubic LiMn{sub 2}O{sub 4} spinel, and {lambda}-MnO{sub 2} (delithiated spinel), all in antiferromagnetic spin configurations. The changes in energy spectra as the Mn oxidation state varies between 2+ and 4+ are illustrated. Preliminary calculations for Co-doped LiMnO{sub 2} are presented, and the destabi… more
Date: December 22, 1998
Creator: Benedek, R.; Prasad, R.; Thackeray, M. M.; Wills, J. M. & Yang, L. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Alkali Treatment of Acidic Solution from Hanford K Basin Sludge Dissolution

Description: Nitric acid solutions will be created from the dissolution of Hanford K Basin sludge. These acidic dissolver solutions must be made alkaline by treatment with NaOH solution before they are disposed to ~ the Tank Waste Remediation System on the Hanford Site. During the alkali treatments, sodium diuranate, hydroxides of iron and aluminum, and radioelements (uranium, plutonium, and americium) will precipitate from the dissolver solution. Laboratory tests, discussed here, were pefiormed to provide … more
Date: December 22, 1998
Creator: Bessonov, A. A.; Yusov, A. B.; Fedoseev, A. M.; Gelis, A. V.; Garnov, A. Y.; Delegard, C. H. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Health and safety considerations for U. S. monitors in the Russian transparency program.

Description: In 1993 the US and the Russian Federation signed an agreement allowing the US to purchase highly enriched uranium (HEU) from Russia over a 20-year period. This Highly Enriched Uranium Purchase Agreement permits the purchase of 500 metric tons of HEU from dismantled Russian nuclear weapons in the form of low-enriched uranium (LEU) for use as power reactor fuel in the US. Under the HEU Agreement, the US and Russia are cooperating in a ''Transparency Program'' to ensure that arms control and nonpr… more
Date: October 22, 1998
Creator: Boggs, C. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Adaptively Learning an Importance Function Using Transport Constrained Monte Carlo

Description: It is well known that a Monte Carlo estimate can be obtained with zero-variance if an exact importance function for the estimate is known. There are many ways that one might iteratively seek to obtain an ever more exact importance function. This paper describes a method that has obtained ever more exact importance functions that empirically produce an error that is dropping exponentially with computer time. The method described herein constrains the importance function to satisfy the (adjoint) … more
Date: June 22, 1998
Creator: Booth, T. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Numerical Models of Broad-Bandwidth Nanosecond Optical Parametric Oscillators

Description: We present three new methods for modeling broad-bandwidth, nanosecond optitcal parametric oscillators in the plane-wave approximation. Each accounts for the group-velocity differences that determine the operating linewidth of unseeded optical parametric oscillators, and each allows the signal and idler waves to develop from quantum noise. The first two methods are based on split-step integration methods in which nonlinear mixing and propagation are calculated separately on alternate steps. One … more
Date: October 22, 1998
Creator: Bowers, M. S.; Gehr, Russell J. & Smith, A. V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

New Microscopic Model of the Staebler-Wronski Effect in Hydrogenated Amorphous Silicon

Description: A new microscopic and kinetic model of light-induced metastability in hydrogenated amorphous silicon (a-Si:H) was recently proposed. Carrier recombination excites H from deep Si-H bonds into a mobile configuration, leaving a threefold-coordinated Si dangling bond (DB) defect at the site of excitation - a process long suspected to be an element of metastable DB production. Normally, mobile H are recaptured at DB defects and neither metastability nor net DB production results. However, when two m… more
Date: October 22, 1998
Creator: Branz, H. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

RF Beam Control System for the Brookhaven Relativistic Heavy ION Collider, RHIC

Description: The Relativistic Heavy Ion Collider, RHIC, is two counter-rotating rings with six interaction points. The RF Beam Control system for each ring will control two 28 MHz cavities for acceleration, and five 197 MHz cavities for preserving the 5 ns bunch length during 10 hour beam stores. Digital technology is used extensively in: Direct Digital Synthesis of rf signals and Digital Signal Processing for, the realization of state-variable feedback loops, real-time calculation of rf frequency, and bunc… more
Date: June 22, 1998
Creator: Brennan, J. M.; Campbell, A.; DeLong, J.; Hayes, T.; Onillon, E.; Rose, J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Overture: an objectoriented framework for solving partial differential equations on overlapping grids

Description: The Overture framework is an object-oriented environment for solving partial differential equations in two and three space dimensions. It is a collection of C++ libraries that enables the use of finite difference and finite volume methods at a level that hides the details of the associated data structures. Overture can be used to solve problems in complicated, moving geometries using the method of overlapping grids. It merges geometry, grid generation, difference operators, boundary conditions,… more
Date: September 22, 1998
Creator: Brown, D L; Henshaw, W D & Quinlan , D J
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

CALDERON COKEMAKING PROCESS/DEMONSTRATION PROJECT

Description: This project deals with the demonstration of a coking process using proprietary technology of Calderon, with the following objectives geared to facilitating commercialization: (1) making coke of such quality as to be suitable for use in hard-driving, large blast furnaces; (2) providing proof that such process is continuous and environmentally closed to prevent emissions; (3) demonstrating that high-coking-pressure (non-traditional) coal blends which cannot be safely charged into conventional by… more
Date: June 22, 1998
Creator: CALDERON, ALBERT
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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