The left-right cross section asymmetry for Z boson production in e{sup +} e{sup {minus}} annihilation (A{sub LR}) is being measured at E{sub cm} 91.5 GeV with the SLD detector at the SLAC Linear Collider (SLC) using a longitudinally polarized electron beam. The electron polarization is continually monitored with a Compton scattering polarimeter, and is typically 22%. At the current time, we have accumulated a sample of 4779 Z events. We find that A{sub LR} = 0.02 {double_bond} 0.07 {doteq} 0.001 where the first error is statistical and the second is systematic. Using this very preliminary measurement, we determine the weak mixing angle defined at the Z boson pole to be sin{sup 2}{sub W}{sup olept} = 0.247 {plus_minus} 0.009.

This work provides a brief overview of past and ongoing efforts at Lawrence Livermore National Laboratory (LLNL) in the area of finite-element modeling of crash and impact problems. The process has been one of evolution in several respects. One aspect of the evolution has been the continual upgrading and refinement of the DYNA, NIKE, and TOPAZ family of finite-element codes. The major missions of these codes involve problems where the dominant factors are high-rate dynamics, quasi-statics, and heat transfer, respectively. However, analysis of a total event, whether it be a shipping container drop or an automobile/barrier collision, may require use or coupling or two or more of these codes. Along with refinements in speed, contact capability, and element technology, material model complexity continues to evolve as more detail is demanded from the analyses. A more recent evolution has involved the mix of problems addressed at LLNL and the direction of the technology thrusts. A pronounced increase in collaborative efforts with the civilian and private sector has resulted in a mix of complex problems involving synergism between weapons applications (shipping container, earth penetrator, missile carrier, ship hull damage) and a more broad base of problems such as vehicle impacts as discussed …

The minimum possible rotational period of pulsars, which are interpreted as rotating neutron stars, is determined by applying a representative collection of realistic nuclear equations of state. It is found that none of the selected equations of state allows for neutron star rotation at periods below 0.8--0.9 ms. Thus, this work strongly supports the suggestion that if pulsars with shorter rotational periods were found, these are likely to be strange-quark-matter stars. The conclusion that the confined hadronic phase of nucleons and nuclei is only metastable would then be almost inescapable, and the plausible ground-state in that event is the deconfined phase of (3-flavor) strange-quark-matter.

This document describes the Westinghouse Savannah River Company's (WSRC) Quality Assurance Program for Defense Waste Processing at the Savannah River Site (SRS). It identifies and describes the planned activities that constitute the required Quality Assurance Program. The work to which the Quality Assurance Program applies includes both the qualification and production of high-level waste forms. The end result of the program is to provide confidence that these high-level waste forms may be safely and acceptably used to dispose of the radioactive waste that results from activities at SRS in support of national defense.

Energy-dependent photoelectron diffraction (EDPD) has been used to determine the surface structure of a surface alloy. Direct imaging has been achieved by Fourier transformation of experimental energy-dependent photoelectron diffraction data. This holographic method, based upon the intersection of contour arcs associated with each measurement direction, can provide vectorial atomic positions with atomic resolution. Experimental analysis is supported by Fourier transformation of simulations from multiple scattering calculations. The surface geometry of c(2x2) Au/Cu(001) has been imaged in an elementally-specific manner, with clear, non-model-dependent discrimination of the surface alloy over the overlayer structure.

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The purpose of this panel is to present different perspectives and opinions regarding the issues surrounding why software should or shouldn't be entrusted with critical (high consequence) functionality.

High gain photoconductive semiconductor switches (PCSS) are being used to produce high power electromagnetic pulses foc (1) compact, repetitive accelerators, (2) ultra-wide band impulse sources, (3) precision gas switch triggers, (4) optically-activated firesets, and (5) high power optical pulse generation and control. High power, sub-nanosecond optical pulses are used for active optical sensors such as compact optical radars and range-gated hallistic imaging systems. Following a brief introduction to high gain PCSS and its general applications, this paper will focus on PCSS for optical pulse generation and control. PCSS technology can be employed in three distinct approaches to optical pulse generation and control: (1) short pulse carrier injection to induce gain-switching in semiconductor lasers, (2) electro-optical Q-switching, and (3) optically activated Q-switching. The most significant PCSS issues for these applications are switch rise time, jitter, and longevity. This paper will describe both the requirements of these applications and the most recent results from PCSS technology. Experiments to understand and expand the limitations of high gain PCSS will also be described.

The Waste Isolation Pilot Plant (WIPP) is the first nuclear waste repository certified by the United States Environmental Protection Agency. Success in regulatory compliance resulted from an excellent natural setting for such a repository, a facility with multiple, redundant safety systems, and from a rigorous, transparent scientific and technical evaluation. The WIPP story, which has evolved over the past 25 years, has generated a library of publications and analyses. Details of the multifaceted program are contained in the cited references. Selected geotechnical highlights prove the eminent suitability of the WIPP to serve its congressionally mandated purpose.

Measurements of dielectric breakdown during high-field electrical stress are typically performed at or near room temperature via constant voltage or current stress methods. In this summary they explore whether useful information might also be obtained by performing current measurements during a temperature ramp at high electric field.

We report on a search for supersymmetry using the DO detector. The 1994-96 data sample of {radical}s = 1:8 TeV {bar p}p collisions was analyzed for events containing two leptons (e or {mu}), two or more jets, and missing transverse energy. Assuming minimal supergravity, with free parameters m{sub 0}, m{sub 1/2} and tan {beta}, various thresholds were employed to optimize the search. No excess of events was observed. We present exclusion contours in the (m{sub 0}, m{sub 1/2}) plane for tan {beta} = 2-6.

Understanding turbulence and mix in compressible flows is of fundamental importance to real-world applications such as chemical combustion and supernova evolution. The ability to run in three dimensions and at very high resolution is required for the simulation to accurately represent the interaction of the various length scales, and consequently, the reactivity of the intermixing species. Toward this end, we have carried out a very high resolution (over 8 billion zones) 3-D simulation of the Richtmyer-Meshkov instability and turbulent mixing on the IBM Sustained Stewardship TeraOp (SST) system, developed under the auspices of the Department of Energy (DOE) Accelerated Strategic Computing Initiative (ASCI) and located at Lawrence Livermore National Laboratory. We have also undertaken an even higher resolution proof-of-principle calculation (over 24 billion zones) on 5832 processors of the IBM, which executed for over an hour at a sustained rate of 1.05 Tflop/s, as well as a short calculation with a modified algorithm that achieved a sustained rate of 1.18 Tflop/s. The full production scientific simulation, using a further modified algorithm, ran for 27,000 timesteps in slightly over a week of n-all time using 3840 processors of the IBM system, clocking a sustained throughput of roughly 0.6 teraflop per second. …

It is estimated that two billion people live without electricity and its services worldwide. In addition, there is a sizeable number of rural villages that have limited electrical service, with either part-day operation by diesel generator or partial electrification. For many villages connected to the grid, power is often sporadically available and of poor quality. The US National Renewable Energy Laboratory (NREL) in Golden, Colorado, has initiated a program that involves hybrid systems, to address these potential electricity opportunities in rural villages through the application of renewable energy technologies.1 The objective of this program is to develop and implement applications that demonstrate the technical performance, economic competitiveness, operational viability, and environmental benefits of renewable rural electric solutions, compared to the conventional options of line extension and isolated diesel mini-grids. Hybrid systems are multi-disciplinary, multi-technology, multi-application programs composed of six activities, including village applications development, computer model development, systems analysis, pilot project development, technical assistance, and Internet-based village power project data base. While the current program emphasizes wind, photovoltaics (PV), and their hybrids with diesel generator, micro-hydro and micro-biomass technologies may be integrated in the future. Thirteen countries are actively engaged in hybrid systems for rural and remote applications and another …

By the end of June 1999, about 250 megawatts of wind generation will have been dedicated in the state of Iowa. This represents the beginning of what is likely to be significant wind capacity development during the next 20 years in the state, as a result of possible public and governmental mandates and consumers' desire for sustainable sources of energy. As the utility industry in the United States moves towards a new structure, renewable energy sources continue to be an important part of new resource development. In this paper, we consider the predicted trends in load growth in Iowa. After accounting for the retirement of nuclear and older fossil fuel facilities over the next 15 years, we estimate Iowa's potential renewable generating capacity through the year 2015 and anticipate the contribution of wind energy to Iowa's portfolio. The Iowa Wind Energy Institute (IWEI) has been monitoring the wind resource in Iowa since June 1994 to obtain wind speed averages at 10, 33 and 50 meters above ground at fourteen geographically dispersed potential wind farm sites. Winds in the Midwest are primarily generated by fronts moving through the region. The Northwest Buffalo Ridge area of Iowa typically has wind speed averages …

The left-right cross section asymmetry for Z boson production in e[sup +] e[sup [minus]] annihilation (A[sub LR]) is being measured at E[sub cm] 91.5 GeV with the SLD detector at the SLAC Linear Collider (SLC) using a longitudinally polarized electron beam. The electron polarization is continually monitored with a Compton scattering polarimeter, and is typically 22%. At the current time, we have accumulated a sample of 4779 Z events. We find that A[sub LR] = 0.02 [double bond] 0.07 [doteq] 0.001 where the first error is statistical and the second is systematic. Using this very preliminary measurement, we determine the weak mixing angle defined at the Z boson pole to be sin[sup 2][sub W][sup olept] = 0.247 [plus minus] 0.009.

The generalized perturbation method, commonly used in connection with the band energy contribution to the energy of a solid to approximate the total energy of an ordered configuration of an alloy, is reformulated with respect to total energy. The connection of the results derived here to those obtained based on the band energy is pointed out, and possible applications of the method is discussed.

This document describes the Westinghouse Savannah River Company`s (WSRC) Quality Assurance Program for Defense Waste Processing at the Savannah River Site (SRS). It identifies and describes the planned activities that constitute the required Quality Assurance Program. The work to which the Quality Assurance Program applies includes both the qualification and production of high-level waste forms. The end result of the program is to provide confidence that these high-level waste forms may be safely and acceptably used to dispose of the radioactive waste that results from activities at SRS in support of national defense.

The minimum possible rotational period of pulsars, which are interpreted as rotating neutron stars, is determined by applying a representative collection of realistic nuclear equations of state. It is found that none of the selected equations of state allows for neutron star rotation at periods below 0.8--0.9 ms. Thus, this work strongly supports the suggestion that if pulsars with shorter rotational periods were found, these are likely to be strange-quark-matter stars. The conclusion that the confined hadronic phase of nucleons and nuclei is only metastable would then be almost inescapable, and the plausible ground-state in that event is the deconfined phase of (3-flavor) strange-quark-matter.

Organically modified alkoxy silanes play an important role in tailoring different properties of silica produced by the sol-gel method. Changes in the size and functionality of the organic group allows control of both physical and chemical properties of the resulting gel, with the kinetics of the polymerization process playing an important role in the design of new siloxane materials. High resolution {sup 29}Si NMR has proven to be valuable tool for monitoring the polymerization reaction, and has been used to investigate a variety of organically modified alkoxy silane systems.

We gain-switch flared waveguide lasers to obtain 14.5 W peak powers and 0.5 nJ pulse energies with laser structures compatible with the generation of diffraction-limited beams. The results are in excellent agreement with a microscopic laser model.

Low temperature electrical performance characteristics of A and T, Moli, and Panasonic 18650 Li-ion cells are described. Ragone plots of energy and power data of the cells for different temperatures from 25 C to {minus}40 C are compared. Although the electrical performance of these cells at and around room temperature is respectable, at temperatures below 0 C the performance is poor. For example, the delivered power and energy densities of the Panasonic cells at 25 C are {approximately}800 W/l and {approximately}100 Wh/l respectively and those at {minus}40 C are <10 W/l and {approximately}5 Wh/l. In order to identify the source for this poor performance at subambient temperatures, both 2- and 3-electrode impedance studies were made on these cells. The 2-electrode impedance data suggests that the cell ohmic resistance remains nearly constant from 25 C to {minus}20 C but increases modestly at {minus}40 C while the overall cell impedance increases by an order of magnitude over the same temperature range. The 3-electrode impedance data of the A and T cells show that the increase in cell resistance comes mostly from the cathode electrolyte interface and very little either from the anode electrolyte interface or from the ohmic resistance of the cell. …

The longevity of high gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 50 million pulses. This was achieved by improving the ohmic contacts through the incorporation of a doped layer beneath the PCSS contacts which is very effective in the suppression of filament formation and alleviating current crowding to improve the longevity of PCSS. Virtually indefinite, damage-free operation is now possible at much higher current levels than before. The inherent damage-free current capacity of the switch depends on the thickness of the doped layers and is at least 100A for a dopant diffusion depth of 4pm. The contact metal has a different damage mechanism and the threshold for damage ({approximately}40A) is not further improved beyond a dopant diffusion depth of about 2{micro}m. In a diffusion-doped contact switch, the switching performance is not degraded when contact metal erosion occurs. This paper will compare thermal diffusion and epitaxial growth as approaches to doping the contacts. These techniques will be contrasted in terms of the fabrication issues and device characteristics.

Plasmas generated by irradiating targets with {approx}20 kJ of laser energy are routinely created in inertial confinement fusion research. X-ray spectroscopy provides one of the few methods for diagnosing the electron temperature and electron density. For example, electron densities approaching 10{sup 24} cm{sup -3} have been diagnosed by spectral linewidths. However, the accuracy of the spectroscopic diagnostics depends on the population kinetics, the radiative transfer, and the line shape calculations. Analysis for the complex line transitions has recently been improved and accelerated by the use of a database where detailed calculations can be accessed rapidly and interactively. Examples of data from Xe and Ar doped targets demonstrate the current analytic methods. First we will illustrate complications that arise from the presence of a multitude of underlying spectral lines. Then, we will consider the Ar He-like 1s{sup 2}({sup 1}S{sub 0}) - 1s3p({sup 1}P{sub 0}) transition where ion dynamic effects may affect the profile. Here, the plasma conditions are such that the static ion microfield approximation is no longer valid; therefore in addition to the width, the details of the line shape can be used to provide additional information. We will compare the data to simulations and discuss the possible pitfalls involved …

Results of using GLO (Global Local Optimizer), a general purpose nonlinear optimization software package for investigating multi-parameter problems in science and engineering is discussed. The package consists of the modular optimization control system (GLO), a graphical user interface (GLO-GUI), a pre-processor (GLO-PUT), a post-processor (GLO-GET), and nonlinear optimization software modules, GLOBAL & LOCAL. GLO is designed for controlling and easy coupling to any scientific software application. GLO runs the optimization module and scientific software application in an iterative loop. At each iteration, the optimization module defines new values for the set of parameters being optimized. GLO-PUT inserts the new parameter values into the input file of the scientific application. GLO runs the application with the new parameter values. GLO-GET determines the value of the objective function by extracting the results of the analysis and comparing to the desired result. GLO continues to run the scientific application over and over until it finds the ``best`` set of parameters by minimizing (or maximizing) the objective function. An example problem showing the optimization of material model is presented (Taylor cylinder impact test).