156 Matching Results

Results open in a new window/tab.

Advanced Model for SBS of a Randomized Laser Beam and Application to Polarization Smoothing Experiments with Preformed Underdense Plasmas (open access)

Advanced Model for SBS of a Randomized Laser Beam and Application to Polarization Smoothing Experiments with Preformed Underdense Plasmas

An advanced statistical model is presented, which describes the SBS of a randomized laser beam interacting with an underdense, expanding plasma. The model accounts for the self-focusing of speckles and for its influence on the speckles SBS reflectivity in the regime where the effect of plasma heating is important. Plasma heating has an important effect on speckle self-focusing and it decreases the SBS threshold and also decreases the SBS reflectivity. The model exhibit a good agreement with the measured SBS levels at the LULI multi-beam facility for a broad range of the laser and plasma parameters and both types of beam smoothing--RPP and PS. Both the model and the experiments confirm that the PS technique allows to control the SBS level more efficiently than RPP.
Date: June 30, 2000
Creator: Labaune, C.; Depierreux, S.; Baldis, H. A.; Huller, S; Myatt, J. & Pesme, D.
Object Type: Article
System: The UNT Digital Library
An Alternative Form of Laser Beam Characterization (open access)

An Alternative Form of Laser Beam Characterization

Careful characterization of laser beams used in materials processing such as welding and drilling is necessary to obtain robust, reproducible processes and products. Recently, equipment and techniques have become available which make it possible to rapidly and conveniently characterize the size, shape, mode structure, beam quality (Mz), and intensity of a laser beam (incident power/unit area) as a function of distance along the beam path. This facilitates obtaining a desired focused spot size and also locating its position. However, for a given position along the beam axis, these devices typically measure where the beam intensity level has been reduced to I/ez of maximum intensity at that position to determine the beam size. While giving an intuitive indication of the beam shape since the maximum intensity of the beam varies greatly, the contour so determined is not an iso-contour of any parameter related to the beam intensity or power. In this work we shall discuss an alternative beam shape formulation where the same measured information is plotted as contour intervals of intensity.
Date: June 30, 2000
Creator: KNOROVSKY,GERALD A. & MACCALLUM,DANNY O.
Object Type: Article
System: The UNT Digital Library
Alternative Fuels and Chemicals From Synthesis Gas Technical Progress Report: Number 23 (open access)

Alternative Fuels and Chemicals From Synthesis Gas Technical Progress Report: Number 23

The overall objectives of this program are to investigate potential technologies for the conversion of synthesis gas to oxygenated and hydrocarbon fuels and industrial chemicals, and to demonstrate the most promising technologies at DOE's LaPorte, Texas, Slurry Phase Alternative Fuels Development Unit (AFDU). The program will involve a continuation of the work performed under the Alternative Fuels from Coal-Derived Synthesis Gas Program and will draw upon information and technologies generated in parallel current and future DOE-funded contracts.
Date: June 30, 2000
Creator: Tijrn, Peter J.
Object Type: Report
System: The UNT Digital Library
Altus Times (Altus, Okla.), Vol. 101, No. 93, Ed. 1 Friday, June 30, 2000 (open access)

Altus Times (Altus, Okla.), Vol. 101, No. 93, Ed. 1 Friday, June 30, 2000

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date: June 30, 2000
Creator: Bush, Michael
Object Type: Newspaper
System: The Gateway to Oklahoma History
Analysis, tuning and comparison of two general sparse solvers for distributed memory computers (open access)

Analysis, tuning and comparison of two general sparse solvers for distributed memory computers

We describe the work performed in the context of a Franco-Berkeley funded project between NERSC-LBNL located in Berkeley (USA) and CERFACS-ENSEEIHT located in Toulouse (France). We discuss both the tuning and performance analysis of two distributed memory sparse solvers (superlu from Berkeley and mumps from Toulouse) on the 512 processor Cray T3E from NERSC (Lawrence Berkeley National Laboratory). This project gave us the opportunity to improve the algorithms and add new features to the codes. We then quite extensively analyze and compare the two approaches on a set of large problems from real applications. We further explain the main differences in the behavior of the approaches on artificial regular grid problems. As a conclusion to this activity report, we mention a set of parallel sparse solvers on which this type of study should be extended.
Date: June 30, 2000
Creator: Amestoy, P. R.; Duff, I. S.; L'Excellent, J. Y. & Li, X. S.
Object Type: Report
System: The UNT Digital Library
Assessment of Thermal Shock Attenuation in the Particle Bed of the Spallation Neutron Source Collimator (open access)

Assessment of Thermal Shock Attenuation in the Particle Bed of the Spallation Neutron Source Collimator

A thermal shock analysis in a particle bed that surrounds the Spallation Neutron Source (SNS) beam tube in the various collimation locations is performed using a detailed thermal/stress wave propagation formulation. The goal of this effort is to assess the response of the particle bed when subjected to the full proton beam under off-normal operating conditions and its ability to attenuate the induced stress shock. Conclusions are drawn on the basis of comparison between the responses of (a) the individual particle bed elements, (b) an arrangement of elements comprising the particle bed and (c) an equivalent porous-less material with the density of the particle bed.
Date: June 30, 2000
Creator: Simos, N.; Ludewig, H.; Walker, J.; Catalan-Lasheras, N.; Wei, J. & Todosow, M.
Object Type: Article
System: The UNT Digital Library
Aviation Safety: Safer Skies Initiative Has Taken Initial Steps to Reduce Accident Rates by 2007 (open access)

Aviation Safety: Safer Skies Initiative Has Taken Initial Steps to Reduce Accident Rates by 2007

A chapter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the Federal Aviation Administration's (FAA) Safer Skies Initiative, focusing on: (1) to what extent addressing the safety problems to be addressed by the initiative will help reduce the fatal accident rate; (2) what progress the initiative has made in identifying and implementing interventions to address each of these safety problems; (3) what progress has been made in assessing the effectiveness of those interventions; and (4) how FAA is coordinating the Safer Skies initiative with other safety activities conducted throughout the agency, in partnership with the aviation industry, and by other federal agencies."
Date: June 30, 2000
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
The Baytown Sun (Baytown, Tex.), Vol. 78, No. 217, Ed. 1 Friday, June 30, 2000 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 78, No. 217, Ed. 1 Friday, June 30, 2000

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: June 30, 2000
Creator: Cash, Wanda Garner
Object Type: Newspaper
System: The Portal to Texas History
Beam Dynamics Analysis and Correction of Magnet Field Imperfections in the SNS Accumulator Ring (open access)

Beam Dynamics Analysis and Correction of Magnet Field Imperfections in the SNS Accumulator Ring

None
Date: June 30, 2000
Creator: Papaphilippou, Y. & Abell, D. T.
Object Type: Article
System: The UNT Digital Library
Beam Extraction From the Sns Ring and Design of Extraction Kickers. (open access)

Beam Extraction From the Sns Ring and Design of Extraction Kickers.

The accumulator ring of the Spallation Neutron Source (SNS) [1] will accumulate a proton beam, injected from a LINAC, into a single bunch containing {approximately} 2.1 x 10{sup 14} protons at a maximum energy of 1.3 GeV. The single bunch with length {approximately}650 nsec and a gap of {approximately}290 nsec will circulate into the accumulator ring for {approximately}1.0 msec before it is extracted into the RTBT transfer line. The accumulation, extraction frequency is set at 60 Hz. This paper discusses the extraction process and the requirements of the fast beam extraction system.
Date: June 30, 2000
Creator: Tsoupas, N.; Blaskiewicz, M.; Lee, Y. Y.; Mi, J. L.; Soukas, A.; Wang, J. G. et al.
Object Type: Article
System: The UNT Digital Library
Beam properties in the SNS accumulator ring due to transverse phase space painting (open access)

Beam properties in the SNS accumulator ring due to transverse phase space painting

None
Date: June 30, 2000
Creator: Beebe-Wang, J.; Lee, Y. Y.; Raparia, D.; Wei, J.; Prior, C. R. & Machida, S.
Object Type: Article
System: The UNT Digital Library
Biodiversity analysis of vegetation on the Nevada Test Site (open access)

Biodiversity analysis of vegetation on the Nevada Test Site

The Nevada Test Site (NTS), located in south-central Nevada, encompasses approximately 3,500 square kilometers and straddles two major North American deserts, Mojave and Great Basin. Transitional areas between the two desert types have been created by gradients in elevation, precipitation, temperature, and soils. From 1996 to 1998, more than 1,500 ecological landform units were sampled at the NTS for numerous biotic and abiotic parameters. The data provide a basis for spatial evaluations of biodiversity over landscape scales at the NTS. Biodiversity maps (species richness vs. species abundance) have been produced. Differences in biodiversity among ecoregions and vegetation alliances are presented. Spatial distribution maps of species' presence and abundance provide evidence of where transition zones occur and the resulting impact on biodiversity. The influences of abiotic factors, such as elevation, soil, and precipitation, on biodiversity are assessed.
Date: June 30, 2000
Creator: Ostler, W. K. & Hansen, D. J.
Object Type: Article
System: The UNT Digital Library
The Boerne Star (Boerne, Tex.), Vol. 95, No. 52, Ed. 1 Friday, June 30, 2000 (open access)

The Boerne Star (Boerne, Tex.), Vol. 95, No. 52, Ed. 1 Friday, June 30, 2000

Semiweekly newspaper from Boerne, Texas that includes local, state, and national news along with advertising.
Date: June 30, 2000
Creator: Keasling, Edna & Fierro, Jennifer
Object Type: Newspaper
System: The Portal to Texas History
Brady Standard-Herald and Heart O' Texas News (Brady, Tex.), Ed. 1 Friday, June 30, 2000 (open access)

Brady Standard-Herald and Heart O' Texas News (Brady, Tex.), Ed. 1 Friday, June 30, 2000

Semiweekly newspaper from Brady, Texas that includes local, state, and national news along with advertising.
Date: June 30, 2000
Creator: Stewart, James E.
Object Type: Newspaper
System: The Portal to Texas History
The Case for a 500 GEV E+E - Linear Collider (open access)

The Case for a 500 GEV E+E - Linear Collider

There are now several proposals that have been put forward from around the world for an e{sup +}e{sup {minus}} linear collider with an initial center of mass energy of 500 GeV. In this paper, the authors discuss why a project of this type deserves priority as the next, major initiative in high energy physics.
Date: June 30, 2000
Creator: Bagger, J.; Baltay, C.; AL, ET; Marciano, W.; Paige, F.; Turcot, A. S. et al.
Object Type: Report
System: The UNT Digital Library
Ceramic Membrane Enabling Technology for Improved IGCC Efficiency, Quarterly Technical Progress Report: April - June 2000 (open access)

Ceramic Membrane Enabling Technology for Improved IGCC Efficiency, Quarterly Technical Progress Report: April - June 2000

None
Date: June 30, 2000
Creator: Prasad, Ravi
Object Type: Report
System: The UNT Digital Library
Chromatic Correction and Optical Compensation in the Sns Accumulator Ring Using Sextupoles. (open access)

Chromatic Correction and Optical Compensation in the Sns Accumulator Ring Using Sextupoles.

The accumulator ring of the Spallation Neutron Source (SNS) will accumulate a high-intensity beam of 2.1 x 10{sup 14} protons in a single bunch with large transverse emittance of 160{pi} mm mrad at 95% beam intensity and energies of 1 to 1.3 GeV. In order to keep low beam losses ({approx} 10{sup {minus}4}) in the ring, it is necessary to control the chromaticity and to minimize the dependence of the optical properties on the momentum spread. In this paper, we describe the procedure to accomplish this by using chromaticity sextupoles. We finally discuss the impact of these sextupoles in non-linear dynamics.
Date: June 30, 2000
Creator: Tsoupas, N.; Gardener, C. J.; Lee, Y. Y.; Papaphilippou, Y. & Wei, J.
Object Type: Article
System: The UNT Digital Library
The Clifton Record (Clifton, Tex.), Vol. 105, No. 52, Ed. 1 Friday, June 30, 2000 (open access)

The Clifton Record (Clifton, Tex.), Vol. 105, No. 52, Ed. 1 Friday, June 30, 2000

Semi-weekly newspaper from Clifton, Texas that includes local, state, and national news along with advertising.
Date: June 30, 2000
Creator: Smith, W. Leon
Object Type: Newspaper
System: The Portal to Texas History
Combustion 2000 (open access)

Combustion 2000

This report presents work carried out under contract DE-AC22-95PC95144 ''Combustion 2000 - Phase II.'' The goals of the program are to develop a coal-fired high performance power generation system (HIPPS) that is capable of: {lg_bullet} thermal efficiency (HHV) {ge} 47% {lg_bullet} NOx, SOx, and particulates {le} 10% NSPS (New Source Performance Standard) {lg_bullet} coal providing {ge} 65% of heat input {lg_bullet} all solid wastes benign {lg_bullet} cost of electricity {le} 90% of present plants Phase I, which began in 1992, focused on the analysis of various configurations of indirectly fired cycles and on technical assessments of alternative plant subsystems and components, including performance requirements, developmental status, design options, complexity and reliability, and capital and operating costs. Phase I also included preliminary R&D and the preparation of designs for HIPPS commercial plants approximately 300 MWe in size. Phase II, had as its initial objective the development of a complete design base for the construction and operation of a HIPPS prototype plant to be constructed in Phase III. As part of a descoping initiative, the Phase III program has been eliminated and work related to the commercial plant design has been ended. The rescoped program retained a program of engineering research and …
Date: June 30, 2000
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Contingent Workers: Incomes and Benefits Lag Behind Those of Rest of Workforce (open access)

Contingent Workers: Incomes and Benefits Lag Behind Those of Rest of Workforce

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on the status of contingent workers, focusing on the: (1) nature and size of the contingent workforce; (2) extent to which contingent workers have access to health insurance and pensions; (3) protections afforded these workers under laws regarding family and medical leave, retirement income, hourly wages, labor relations, civil rights, and health and safety; and (4) options available for providing contingent workers increased access to employee benefits and increased coverage under laws designed to protect workers."
Date: June 30, 2000
Creator: United States. General Accounting Office.
Object Type: Report
System: The UNT Digital Library
Coordination Between the HEU Transparency Program and the Material Protection, Control and Accountability Program (open access)

Coordination Between the HEU Transparency Program and the Material Protection, Control and Accountability Program

DOE sponsored programs such as Material Protection Control and Accountability (MPC&A) and implementation of the Highly-Enriched Uranium (HEU) Transparency Program send US personnel into Russian nuclear facilities and receive Russian representatives from these programs. While there is overlap in the Russian nuclear facilities visited by these two programs, there had not been any formal mechanism to share information between them. Recently, an MPC&A/HEU Working Group was developed to facilitate the sharing of appropriate information and to address concerns expressed by Minatom and Russian facility personnel such as US visit scheduling conflicts. This paper discusses the goals of the Working Group and ways it has helped to allow the programs to work more efficiently with the Russian facilities.
Date: June 30, 2000
Creator: Glaser, J.; Hernandez, J.; Dougherty, D.; Bieniawski, A.; Cahalane, P. & Mastal, E.
Object Type: Article
System: The UNT Digital Library
Correction schemes for the normal octupole and decapole errors in the LHC dipoles (open access)

Correction schemes for the normal octupole and decapole errors in the LHC dipoles

None
Date: June 30, 2000
Creator: Papaphilippou, Y.
Object Type: Article
System: The UNT Digital Library
Dallas Voice (Dallas, Tex.), Vol. 17, No. 9, Ed. 1 Friday, June 30, 2000 (open access)

Dallas Voice (Dallas, Tex.), Vol. 17, No. 9, Ed. 1 Friday, June 30, 2000

Weekly newspaper from Dallas, Texas that includes local, state, and national news and advertising of interest to the Lesbian, Gay, Bisexual, and Transgender (LGBT) community.
Date: June 30, 2000
Creator: Vercher, Dennis
Object Type: Newspaper
System: The UNT Digital Library
DART's (Dallas Area Rapid Transit) LNG Bus Fleet Start-Up Experience (Alternative Fuel Transit Buses Brochure) (open access)

DART's (Dallas Area Rapid Transit) LNG Bus Fleet Start-Up Experience (Alternative Fuel Transit Buses Brochure)

This report, based on interviews and site visits conducted in October 1999, describes the start-up activities of the DART liquefied natural gas program, identifying problem areas, highlighting successes, and capturing the lessons learned in DART's ongoing efforts to remain at the forefront of the transit industry.
Date: June 30, 2000
Creator: Battelle
Object Type: Book
System: The UNT Digital Library