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in subjects: "Compression"

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Acceleration of beam ions during major radius compression in TFTR

Tangentially co-injected deuterium beam ions were accelerated from 82 keV up to 150 keV during a major radius compression experiment in TFTR. The ion energy spectra and the variation in fusion yield were in good agreement with Fokker-Planck code simulations. In addition, the plasma rotation velocity was observed to rise during compression.

Date: September 1, 1985

Creator: Wong, K. L.; Bitter, M.; Hammett, G. W.; Heidbrink, W.; Hendel, H.; Kaita, R. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

The electronic structure of condensed molecular systems

We have reviewed some of the basic properties of the electronic structure of condensed molecular systems. For the rare-gas solids, we concentrated our discussion on changes in the ground- and excited-state crystal-atomic wave functions as calculated with an approximate theoretical method. Compression of these wave functions leads to a softening of the equation of state at high densities, which seems to account for much of the total many-body effects. This compression is a true many-body effect … more

Date: January 1, 1988

Creator: LeSar, R.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electrical Conductivity Measurements in Shock Compressed Liquid Nitrogen

The electrical conductivity of shock compressed liquid nitrogen was measured in the pressure range 20 to 50 GPa using a two-stage light-gas gun. The conductivities covered a range 4 x 10/sup -2/ to 1 x 10/sup 2/ ohm/sup -1/ cm/sup -1/. The data are discussed in terms of a liquid semiconductor model below the onset of the dissociative phase transition at 30 GPa. 15 refs., 1 fig.

Date: June 1, 1985

Creator: Hamilton, D. C.; Mitchell, A. C. & Nellis, W. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Shock-compression properties of ceramics

High-resolution, time-resolved shock compression measurements have been performed on high-strength monolithic ceramics to assess equation-of-state, phase transformation and flow properties. A substantial base of data has been obtained on a range of ceramics including aluminium nitride, aluminum oxide, boron carbide, silicon carbide, titanium diboride and zirconium dioxide. These data provide material response properties for nonlinear elastic compliance, pressure-induced phase transformation, sh… more

Date: January 1, 1991

Creator: Grady, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Sulfur hexafluoride transfer and storage system of the Holifield Heavy Ion Research Facility: some thermodynamic properties

The transfer of SF/sub 6/ insulating gas from the 25 MV accelerator pressure vessel (volume = 80,000 ft/sup 3/) into liquid storage tanks (volume = 6,000 ft/sup 3/) is accomplished by means of two three-stage piston compressors operating in parallel. Gas from the first and second compression stages is passed through heat exchangers prior to injection into subsequent stages while gas from the third stage is cooled and/or liquified by a third exchanger/condenser. Tabulated thermodynamic data were… more

Date: February 1, 1978

Creator: Milner, W. T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Estimates of post-acceleration longitudinal bunch compression

A simple analytic method is developed, based on physical approximations, for treating transient implosive longitudinal compression of bunches of heavy ions in an accelerator system for ignition of inertial-confinement fusion pellet targets. Parametric dependences of attainable compressions and of beam path lengths and times during compression are indicated for ramped pulsed-gap lines, rf systems in storage and accumulator rings, and composite systems, including sections of free drift. It appear… more

Date: November 25, 1977

Creator: Judd, D.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Proposal for study of vacuum adiabatic compression of relativistic electron beam generated by a foilless diode. [5 to 50 MeV]

A theoretical investigation to study the generation of an intense relativistic electron beam by a foilless diode and subsequent adiabatic compression is proposed. 2 figures, 1 table, 39 references.

Date: February 1, 1978

Creator: Thode, L.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Collector sealants and breathing. Final Report, 25 September 1978-31 December 1979

The objectives of this program were: (1) to investigate the pertinent properties of a variety of possible sealants for solar collectors and identify the most promising candidates, and (2) to study the effect of breathing in flat-plate, thermal solar collector units. The study involved two types of sealants, Class PS which includes preformed seals or gaskets and Class SC which includes sealing compounds or caulks. It was the intent of the study to obtain data regarding initial properties of cand… more

Date: February 20, 1980

Creator: Mendelsohn, M A; Luck, R M; Yeoman, F A & Navish, Jr, F W

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Pattern formation by shock processes

Shock waves in condensed media often produce and leave behind periodic patterns and textures. These patterns have been observed both in real time and in postmortem examination. In many cases the patterns can be related to analogous Pattern-forming mechanisms in classical fluid dynamics, such as the Rayleigh-Taylor and Helmholtz instabilities. In other cases, the textures arise from peculiarities in the dynamic stress state immediately behind the leading edge of the shock wave. Periodic waves in… more

Date: January 1, 1983

Creator: Shaner, J.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Strategies for understanding the deflagration-to-detonation transition

The deflagration-to-detonation (DDT) phenomenon has been studied for many years. However, no comprehensive model of the DDT process is available. It is important to understand the mechanism by which an explosive will detonate when the source of ignition is a weak shock or flame, and to able to predict this response. We have identified several key areas of the DDT problem which need to be understood before any such prediction can be made, and have established a modest program to obtain a more fu… more

Date: January 1, 1992

Creator: Asay, B.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Synthesis of Al/Al sub 3 Ti two-phase alloys by mechanical alloying

We have mechanically alloyed mixtures of elemental powders to prepare fine-grain two-phase A1/A1{sub 3}Ti powders at the compositions A1-20at% Ti and Al-10at% Ti. Hexane was used to prevent agglomeration of the powder during MA. Carbon from the decomposition of the hexane was incorporated in the powder. It reacted with Ti to form a fine dispersion of carbides in the final hot-pressed compact. We consolidated the mechanically alloyed powders by hot-pressing. Yield strength and ductility were mea… more

Date: January 1, 1991

Creator: Srinivasan, S.; Chen, S.R. & Schwarz, R.B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A high-power SLED 2 pulse compression system

The enhancement of peak power by means of RF pulse compression has found important application for driving high energy electron linacs, the SLAC linac in particular. The SLAC Energy Doubler (SLED), however, yields a pulse shape in the form of a decaying exponential which limits the applicability of the method. Two methods of improving this situation have been suggested: binary pulse compression (BPC), in which the pulse is compressed by successive factors of two, and SLED II in which the pair o… more

Date: March 1, 1992

Creator: Kroll, N. M.; Farkas, Z. D.; Lavine, T. L.; Menegat, A.; Ruth, R. D.; Wilson, P. B. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanical properties of polystyrene bead encapsulation foam

The tensile and compressive properties of polystyrene bead foam used as an encapsulant for electronic devices were determined for densities ranging from 0.3 to 0.6 g/cm/sup 3/. Data were generated for these properties at -54, 25, and 74/sup 0/C. Data previously reported for 0.2 g/cm/sup 3/ are included.

Date: March 1, 1980

Creator: Fossey, D.J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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High-pressure ion-thermal properties of metals from ab initio interatomic potentials

It has recently become possible for the first time to calculate ab initio two-ion and three-ion interatomic potentials in d-electron transition metals. The nature of these potentials for the 3d series metals is discussed. In the case of copper, where three-ion contributions may be neglected, application is made to the ion-thermal component of the equation of state and to the calculation of melting on the shock Hugoniot. 13 refs., 3 figs.

Date: June 1, 1985

Creator: Moriarty, J.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Effects of flow on density profiles in laser irradiated plasmas

When the plasma outflow velocity relative to the critical surface is supersonic, compressional density profiles can form in the critical region. These compressions involve dissipative processes like those in collisionless shocks; associated plasma instabilities and reflected ions may inhibit energy transport and enhance laser light absorption.

Date: October 18, 1977

Creator: Max, C.E. & McKee, C.F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Inertial confinement fusion (ICF). [Review of research progress]

The principal goal of the inertial confinement fusion program is the development of a practical fusion power plant in this century. Rapid progress has been made in the four major areas of ICF--targets, drivers, fusion experiments, and reactors. High gain targets have been designed. Laser, electron beam, and heavy ion accelerator drivers appear to be feasible. Record-breaking thermonuclear conditions have been experimentally achieved. Detailed diagnostics of laser implosions have confirmed predi… more

Date: October 12, 1977

Creator: Nuckolls, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Efficient access of compressed data

A compression technique is presented that allows a high degree of compression but requires only logarithmic access time. The technique is a constant suppression scheme, and is most applicable to stable databases whose distribution of constants is fairly clustered. Furthermore, the repeated use of the technique permits the suppression of a multiple number of different constants. Of particular interest is the application of the constant suppression technique to databases the composite key of whic… more

Date: June 1, 1980

Creator: Eggers, S.J. & Shoshani, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Analysis of CO2 Separation from Flue Gas, Pipeline Transportation, and Sequestration in Coal

This report was written to satisfy a milestone of the Enhanced Coal Bed Methane Recovery and CO2 Sequestration task of the Big Sky Carbon Sequestration project. The report begins to assess the costs associated with separating the CO2 from flue gas and then injecting it into an unminable coal seam. The technical challenges and costs associated with CO2 separation from flue gas and transportation of the separated CO2 from the point source to an appropriate sequestration target was analyzed. The r… more

Date: September 1, 2007

Creator: Robertson, Eric P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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A METHOD FOR STATIC-FIELD COMPRESSION IN AN ELECTRON-RING ACCELERATOR

A review of methods for static-field compression of an electron ring is shown to suggest advantages for a method in which there is no axial acceleration or deceleration of the ring. In the method proposed here the static magnetic field itself is o such a character that the electrons are neither focused nor defocused in the axial direction. The integrity and movement of the ring through the compressor is controlled by a small traveling magnetic well. The feasibility of creating such a traveling … more

Date: February 20, 1969

Creator: Laslett, L.Jackson & Sessler, Andrew M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Oxidation and combustion of the n-hexene isomers: a wide range kinetic modeling study

A detailed chemical kinetic mechanism has been developed to study the oxidation of the straight-chain isomers of hexene over a wide range of operating conditions. The main features of this detailed kinetic mechanism, which includes both high and low temperature reaction pathways, are presented and discussed with special emphasis on the main classes of reactions involved in alkene oxidation. Simulation results have been compared with experimental data over a wide range of operating conditions in… more

Date: March 12, 2008

Creator: Mehl, M; Vanhove, G; Pitz, W J & Ranzi, E

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Use beam steering dipoles to minimize aberrations associated with off-centered transit through the induction bunching module. Design an improved NDCX-I drift compression section to make best use of the new bunching module to optimize planned initial NDCX-I target experiments

This milestone has been met by: (1) calculating steering solutions and implementing them in the experiment using the three pairs of crossed magnetic dipoles installed in between the matching solenoids, S1-S4. We have demonstrated the ability to center the beam position and angle to<1 mm and<1 mrad upstream of the induction bunching module (IBM) gap, compared to uncorrected beam offsets of several millimeters and milli-radians. (2) Based on LSP and analytic study, the new IBM, which has tw… more

Date: March 28, 2008

Creator: HIFS-VNL; Seidl, Peter; Seidl, P.; Barnard, J.; Bieniosek, F.; Coleman, J. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Laboratory evaluation of frozen soil target materials with a fused interface.

To investigate the performance of artificial frozen soil materials with a fused interface, split tension (or 'Brazilian') tests and unconfined uniaxial compression tests were carried out in a low temperature environmental chamber. Intact and fused specimens were fabricated from four different soil mixtures (962: clay-rich soil with bentonite; DNA1: clay-poor soil; DNA2: clay-poor soil with vermiculite; and DNA3: clay-poor soil with perlite). Based on the 'Brazilian' test results and density mea… more

Date: October 1, 2004

Creator: Bronowski, David R. & Lee, Moo Yul

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Toward Fast Computation of Dense Image Correspondence on the GPU

Large-scale video processing systems are needed to support human analysis of massive collections of image streams. Video, from both current small-format and future large-format camera systems, constitutes the single largest data source of the near future, dwarfing the output of all other data sources combined. A critical component to further advances in the processing and analysis of such video streams is the ability to register successive video frames into a common coordinate system at the pix… more

Date: August 13, 2007

Creator: Duchaineau, M; Cohen, J & Vaidya, S

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Production of Gratings for High-Energy Petawatt-Class Lasers

At the time of this writing, we have manufactured and delivered more than 25 multilayer dielectric diffraction gratings from 470-800 mm in long aperture for pulse compression on Petawatt-class,1-micron laser systems being built at government and university facilities in the U.S and elsewhere. We present statistics of diffraction efficiency and its spatial uniformity, diffracted wavefront, and laser damage results on witness gratings. We also discuss yield, failure modes, and manufacturing impro… more

Date: June 14, 2006

Creator: Nguyen, H. T.; Carlson, T. C.; Hoaglan, C. R.; Nissen, J. D.; Aasen, M. D.; Peterson, J. E. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department