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 …

Nearly all industrial facilities have been responsible for introducing synthetic chemicals into the environment. The Savannah River Site is no exception. Several areas at the site have been contaminated by chlorinated volatile organic chemicals. Because of the persistence and refractory nature of these contaminants, a complete clean up of the site will take many years. A major focus of the mission of the Environmental Sciences Section of the Savannah River Technology Center is to develop better, faster, and less expensive methods for characterizing, monitoring, and remediating the subsurface. These new methods can then be applied directly at the Savannah River Site and at other contaminated areas in the United States and throughout the world. The Environmental Sciences Section has hosted field testing of many different monitoring technologies over the past two years primarily as a result of the Integrated Demonstration Program sponsored by the Department of Energy`s Office of Technology Development. This paper provides an overview of some of the technologies that have been demonstrated at the site and briefly discusses the applicability of these techniques.

These lecture notes review the LDA-KKR-CPA method for treating the electronic structure and energetics of random alloys and the MF-CF and GPM theories of ordering and phase stability built on the LDA- KKR-CPA description of the disordered phase. Section 2 lays out the basic LDA-KKR-CPA theory of random alloys and some applications. Section 3 reviews the progress made in understanding specific ordering phenomena in binary solid solutions base on the MF-CF and GPM theories of ordering and phase stability. Examples are Fermi surface nesting, band filling, off diagonal randomness, charge transfer, size difference or local strain fluctuations, magnetic effects; in each case, an attempt is made to link the ordering and the underlying electronic structure of the disordered phase. Section 4 reviews calculations of electronic structure of {beta}-phase Ni{sub c}Al{sub 1-c} alloys using a version of the LDA-KKR-CPA codes generalized to complex lattices.

I review the current determinations of {alpha}{sub s}. Attention is given to the theoretical uncertainties inherent in most determinations. all current determinations are consistent with an average of {alpha}{sub s}(M{sub Z}) = 0.119{plus_minus}0.005. Prospects for reduction of the errors in the future are discussed.

A two-dimensional fluid code called UEDGE is used to simulate the edge plasma in tokamak divertors and to evaluate methods for reducing the heat load on divertor plates by radiating some of the power before it reaches the plates. UEDGE is a fully-implicit code being developed jointly by us, D. A. Knoll and R. B. Campbell. For these studies, UEDGE uses a banded matrix solver and a fixed-fraction impurity model. Work is presently underway with Knoll and Campbell to include a memory-efficient iterative solver and a model of impurity transport. Simulations of the proposed TPX device show that a few percent nitrogen concentration in the scrape-off layer can radiate up to 80% of the divertor power, thus reducing the peak heat flux and electron temperature at the divertor plate to acceptable values. A comparison of the neutral gas distribution from UEDGE with results from the DEGAS Monte Carlo neutrals code confirms the validity of our fluid neutrals model.

After a number of refinements, the stability and ease of tuning of the LBL AECR ion source are greatly improved. Several nuclear science experiments have now used cyclotron ion beams injected by the AECR ion source and have taken advantage of its good short and long term-stability and high performance. Refinements include installation of a dc filament power supply for the electron gun, improved gas flow control.and temperature stabilization of parts of the microwave transmission network. Measurements of the mean plasma potential and plasma potential difference were made on the AECR and the LBL ECR sources. The absolute. mean potentials of plasmas of oxygen, argon, and argon mixed with oxygen in the AECR have been determined. These plasma potentials are positive with respect to the plasma wall and are on the order of a few tens of volts for microwave power up to 600 W and normal operating gas flow. Electrons injected by an electron gun into the AECR plasma reduce the plasma potentials. Beam energy spreads of oxygen, argon and argon mixed with oxygen have also been measured. Measurement of the plasma potential difference between the first and the second stage of the LBL ECR ion source shows that …

At Lawrence Livermore National Laboratory (LLNL) we have recently developed several techniques for volume visualization of scalar and vector fields, all of which use back-to-front compositing. The first renders volume density clouds by compositing polyhedral volume cells or their faces. The second is a ``splatting`` scheme which composites textures used to reconstruct the scalar or vector fields. One version calculates the necessary texture values in software, and another takes advantage of hardware texture mapping. The next technique renders contour surface polygons using semi-transparent textures, which adjust appropriately when the surfaces deform in a flow, or change topology. The final one renders the ``flow volume`` of smoke or dye tracer swept out by a fluid flowing through a small generating polygon. All of these techniques are applied to a climate model data set, to visualize cloud density and wind velocity.

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.

A vapor-phase, reagent-based, fiber optic trichloroethylene (TCE) sensor developed by Lawrence Livermore National Laboratory (LLNL) was demonstrated at the Savannah River Site (SRS) in two configurations. The first incorporated the sensor into a down-well instrument bounded by two inflatable packers capable of sealing an area for discrete depth analysis. The second involved an integration of the sensor into the probe tip of the Army Corps of Engineers Waterways Experiment Station (WES) cone penetrometry system. Discrete depth measurements of vapor-phase concentrations of TCE in the vadose zone were successfully made using both configurations. These measurements demonstrate the first successful in situ sensing (as opposed to sampling) of TCE at a field site.

Hazardous debris includes objects contaminated with hazardous waste. Examples of debris include tree stumps, timbers, boulders, tanks, piping, crushed drums, personal protective clothing, etc. Most of the hazardous debris encountered comes from Superfund sites and other facility remediation, although generators and treaters of hazardous waste also generate hazardous debris. Major problems associated with disposal of debris includes: Inappropriateness of many waste treatments to debris; Difficulties in obtaining representative samples; Costs associated with applying waste specific treatments to debris; Subtitle C landfill space was being used for many low hazard debris types. These factors brought about the need for debris treatment technologies and regulations that addressed these issues. The goal of such regulation was to provide treatment to destroy or remove the contamination if possible and, if this is achieved, to dispose of the cleaned debris as a nonhazardous waste. EPA has accomplished this goal through promulgation of the Hazardous Debris Rule, August 18, 1992.

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.

With statistical analysis of global data from one, two and four stellarators, it is possible to draw limited conclusions whether Gyro- Bohm or Bohm scaling prevails. Either scaling may be favored, depending on whether corrections are included for possible {Beta} and v{sub *} corrections and whether all data are taken, or selected cases with low collisionality, or low net toroidal current, or with ECH heating applied, and so on. Monte Carlo-like simulations are used to test reliability of inferences about power-law scaling exponents made from data having substantial statistical variance and collinearity of control parameters. These show that for reliable conclusions, statistical studies should be augmented; more directed experimental studies are needed, with well controlled discharges and radially resolved data - such as those already begun on ATF and W7-AS.