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.

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.

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.

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.

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.

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."

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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.

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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.

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.

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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.

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 …

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."

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.

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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.

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on the Department of Defense's (DOD) inventory management, focusing on the: (1) extent to which orders exceeded requirements when the orders were placed; and (2) processes for cancelling orders that exceeded requirements."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the Labor-Management Reporting and Disclosure Act (LMRDA) of 1959, focusing on: (1) the Department of Labor's organizational structure and use of fiscal year (FY) 1999 resources to implement LMRDA; and (2) how the Department of Labor administers and enforces each title of the act for which it is responsible."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO provided information on the federal costs and risks of a proposed program for the Department of Veterans Affairs (VA) to guarantee small business loans to veterans, focusing on: (1) the federal credit costs and risks of the proposed program; (2) the cost impact of alternative borrower requirements in the implementation of the proposed program; and (3) the administrative issues resulting from VA's implementation of the proposed program."

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The Disposal Container Handling System receives and prepares new disposal containers (DCs) and transfers them to the Assembly Transfer System (ATS) or Canister Transfer System (CTS) for loading. The system receives the loaded DCs from ATS or CTS and welds the lids. When the welds are accepted the DCs are termed waste packages (WPs). The system may stage the WP for later transfer or transfer the WP directly to the Waste Emplacement/Retrieval System. The system can also transfer DCs/WPs to/from the Waste Package Remediation System. The Disposal Container Handling System begins with new DC preparation, which includes installing collars, tilting the DC upright, and outfitting the container for the specific fuel it is to receive. DCs and their lids are staged in the receipt area for transfer to the needed location. When called for, a DC is put on a cart and sent through an airlock into a hot cell. From this point on, all processes are done remotely. The DC transfer operation moves the DC to the ATS or CTS for loading and then receives the DC for welding. The DC welding operation receives loaded DCs directly from the waste handling lines or from interim lag storage for welding …

Testimony issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed the District of Columbia's management reform initiatives."