A search for cosmological supernovae has discovered a number of a type la supernovae. In particular, one at z = 0.458 is the most distant supernova yet observed. There is strong evidence from measurements of nearby type Ia supernovae that they can be considered as 'standard candles'. We plan to use these supernovae to measure the deceleration in the general expansion of the universe. The aim of our experiment is to try and observe and measure about 30 such distant supernovae in order to obtain a measurement of the deceleration parameter q{sub 0} which is related to {Omega}. Here {Omega} is the ratio of the density of the universe to the critical density, and we expect a measurement with an accuracy of about 30%.

This paper presents work to develop benchmarked theoretical models of scrape-off-layer (SOL) characteristics in diverted tokamaks by comparing shot simulations using the UEDGE plasma fluid and DEGAS neutral transport codes to measurements of the DIII-D SOL plasma. The experimental data include the radial profiles of n{sub e} T{sub e}, and T{sub i}, the divertor exhaust power, the intensity of H{sub {alpha}} emission, and profiles of the radiated power. A very simple model of the anomalous perpendicular transport rates produces consistency between the calculated and measured radial profiles of the divertor power, and of the midplane densities and temperatures. Experimentally, the measured exhaust power is now 80--90% of the input power. The simulated peak power on the outer leg of the divertor floor is now within 20% of the measured power. Various sensitivities of these comparisons to model assumptions are described. Finally, these benchmarked models have been used to examine the effects of various baffle configurations for the Radiative Divertor Upgrade in DIII-D.

Enclosed are proceedings of the workshop on Internal Dosimetry held on Atlanta, Georgia in April 1992. The recommendations from the Workshop were considered by the CIRRPC Subpanel on Occupational Radiation Protection Research in identifying those areas to be undertaken by individual Federal Agencies or in cooperative efforts. This document presents summaries of the following sessions: A.1 Applications and limitations of ICRP and other metabolic models, A.2 Applications and implementation of proposed ICRP lung model, A.3 Estimates of intake from repetitive bioassay data, A.4 Chelation models for plutonium urinalysis data, B.1 Transuranium/uranium registry data, B.2 Autopsy tissue analysis, B.3 Bioassay / Whole body counting, B.4 Data base formatting and availability, C.1 An overview of calculational techniques in use today, C.2 The perfect code, C.3 Dose calculations based on individuals instead of averages, C.4 From macro dosimetry to micro dosimetry.

We give an algorithm for triangulating n-vertex polygonal regions (with holes) so that no angle in the final triangulation measures more than {pi}/2. The number of triangles in the triangulation is only 0(n), improving a previous bound of 0(n{sup 2}), and the worst-case running time is 0(n log{sup 2} n). The basic technique used in the algorithm, recursive subdivision by disks, is new and may have wider application in mesh generation. We also report on an implementation of our algorithm.

A Multipurpose Canister (MPC) is analyzed for critical stresses that occur during normal handling conditions and accidental scenarios. Linear and Non-linear Finite Element Analysis is performed and the stresses at various critical locations in the MPC and its weldments are studied extensively. Progressive failure analysis of the MPC`s groove and fillet welds, is presented. The structural response of the MPC to dynamic lifting loads, to loads resulting from an accidental slippage of a crane cable carrying the MPC, and from the impact between two canisters, is evaluated. Nonlinear structural analysis is used in the evaluation of the local buckling and the ultimate failure phenomena in the shell when the steel is in the strain hardening state during impact. Results make a case for increasing the thickness of the shell and all the welds.

In particle methods, each particle represents a finite region over which there is a distribution of the field quantity of interest. The field value at any point is calculated by summing the distribution functions for all the particles. This summation procedure does not require the use of any connectivities to generate continuous fields. Various AVS modules and networks have been developed that enable us to visualize the results from particle methods. This will be demonstrated by visualizing a numerical simulation of a rising, chaotic bubble. In this fluid dynamics simulation, each particle represents a region with a specified vorticity distribution.

When a weak magnetic field is applied to a superconducting strip or disk of thickness d (of the order of the penetration depth {lambda}) much less than its width or radius, induced super-currents flow so as to prevent magnetic flux from penetrating the superconductor (except within {lambda} of the edge). A stronger field causes vortices to enter, and the profiles of the macroscopic flux density B are determined by critical-state equations describing bulk pinning. Near the sample edge, where the vortices are, the magnitude of the current density J is J{sub c}. In vortex-free regions of the sample, the magnitude of J is less than J{sub c} but is not zero. The profiles of B can be calculated analytically by assuming that J, averaged over the film thickness, is given by the difference between the values of the tangential component of B at the top and bottom surfaces of the film. This paper examines the basis for this assumption, which is equivalent to assuming that the current density is determined solely by the curvature of H, rather than by the gradient of its magnitude. It is shown that this is a good approximation for thin-film strips and disks.

Procedures exist for waste characterization, but waste minimization and pollution prevention have not usually played a role in development of these procedures. The US Department of Energy (DOE) expects to require several million characterizations over a 30-year period to accomplish the Department`s goals in environmental restoration and waste management. The waste generated by the analytical procedures used for characterizations is a significant source of new DOE waste. We have begun investigating ways to reduce these secondary wastes, focusing on three areas: microanalysis using flow injection; reduction of solvent volume required for dissolution of waste samples for radiochemical analysis; and alternative samples preparation for analysis of organic constituents in waste samples. Preliminary results are reported.

Alkali metal catalyzed reactions between CO{sub 2}-containing brines and portland cement-based well cements can result in rapid strength reductions, increased permeability and casing corrosion, reduced well life, increased costs, and environmental concerns. Materials formed by acid-base reactions between calcium aluminate compounds and phosphate-containing solutions yield high strength, low permeability and CO{sub 2}-resistant cements when cured in hydrothermal environments. The cementing formulations are pumpable for several hours at temperatures up to 150C, thereby making their use for well completions technically feasible. When this cementing matrix was exposed in an autoclave containing Na{sub 2}CO{sub 3}-saturated brine for 120 days, < 0.4 wt% CaCO{sub 3} was produced. A conventional portland cement-based well completion material will form {approx} 10 wt% CaCO{sub 3} after only 7 days exposure. Addition of hollow aluminosilicate microspheres to the uncured matrix constituents yields slurries with densities as low as {approx} 1.2 g/cc which cure to produce materials with properties meeting the criteria for well cementing. Laboratory characterization is nearing completion, engineering scale-up is underway, and plans for field testing in a variety of geothermal fluids are being made.

Local measurements of n{sub e} and T{sub e} in the divertor region are necessary for a more complete understanding of divertor physics. We have designed an extension to the existing multipulse Thomson scattering system to measure n{sub e} in the range 5 {times} 10{sup 18} to 5 {times} 10{sup 20} m{sup {minus}3} and T{sub e} 5--500 eV, with 1 cm resolution from 1--21 cm above the floor of the DIII-D vessel, in the region of the X-point for lower single-null diverted plasmas. One of the existing 8, 20 Hz, ND:YAG lasers will be redirected to a separate vertical port, and viewed radially with a specially designed, f/6.8 lens. Fiber optics carry the light to additional polychromators whose interference filters have been optimized for low T{sub e} measurements. Other aspect of the system, including the beam path to the vessel, polychromator design, real time data acquisition, laser control, calibration facility, and DIII-D timing and data acquisition interface will be shared with the existing multipulse Thomson system. An in-situ laser alignment monitor will provide alignment information for each laser pulse.

For central p+A and Si+A collisions, the average projectile baryon stopping has been determined. The average rapidity loss of the projectile baryons is 0.85{+-}0.1, 1.35{+-}0.1, 1.50{+-}0.28, 1.66{+-}0.21, 1.88{+-}0.17 and 2.11{+-}0.13 for Si+Al, Si+Au, p+Be, p+Al, p+Cu and p+Au, respectively. For central Si+Au collisions, significant deviations from exponential M{sub {perpendicular}} dependence of the differential cross-sections are found. Protons are suppressed at low P{sub {perpendicular}} and pions are enhanced relative to a simple exponential in M{sub {perpendicular}}. This is ascribed to Fermi/Bose effects, and for pions the full (Y,pt) distributions can be well fit by a single source thermal distribution. Within errors both the temperature and chemical potential are equal to the pion mass. Pion densities of approximately 0.1 fm{sup {minus}3} for each species, or {approximately}0.3 fm{sup {minus}3} overall, are found if thermalization of the pions is assumed. This density corresponds to a hard sphere radius of 4.0 to 4.5 fm, in good agreement with pion and proton interferometry measurements.

In this presentation, we present modeling of DDT in porous energetic materials and experimental studies of a time-resolved, shock compression of highly porous inert and reactive materials. This combined theoretical and experimental studies explore the nature of the microscale processes of consolidation, deformation and reaction which are key features of the shock response of porous or damaged energetic materials. The theoretical modeling is based on the theory of mixtures in which multiphase mixtures are treated in complete nonequilibrium allowing for internal boundary effects associated mass/momentum and energy exchange between phases, relative flow, rate-dependent compaction behavior, multistage chemistry and interphase boundary effects. Numerous studies of low-velocity impacts using a high resolution adaptive finite element method are presented which replicate experimental observations. The incorporation of this model into multi-material hydrocode analysis will be discussed to address the effects of confinement and its influence on accelerated combustion behavior. The experimental studies will focus on the use of PVDF piezoelectric polymer stress-rate gauge to precisely measure the input and propagating shock stress response of porous materials. In addition to single constituent porous materials, such as granular HMX, we have resolved shock waves in porous composite intermetallic powders that confirm a dispersive wave nature which …

This report contains abstracts from the fourth international colloquium on x-ray lasers.

Today`s highly competitive global economy is being driven by increasingly rapid technological development. This paper explores the problems of math and science illiteracy in the United States and the potential impact on our economic survival in this environment during the next century. Established educational methods that reward task performance, emphasize passive lecture, and fail to demonstrate relevance to real life are partly to blame. Social norms, stereotypes, and race and gender bias also have an impact. To address this crisis, we need to question the philosophy of an educational system that values task over concept. Many schools have already initiated programs at all grade levels to make math and science learning more relevant, stimulating, and fun. Teaching methods that integrate math and science learning with teamwork, social context, and other academic subjects promote the development of higher-order thinking skills and help students see math and science as necessary skills.

Numerical simulation of dynamic fracture and failure processes in solid continua using Lagrangian finite element techniques is the subject of discussion in this investigation. The specific configurations in this study include penetration of steel projectiles into aluminum blocks and concrete slabs. The failure mode in the aluminum block is excessive deformation while the concrete slab fails by hole growth, spallation, and scabbing. The transient dynamic finite element code LS-DYNA2D was used for the numerical analysis. The erosion capability in LS-DYNA2D was exercised to carry out the fracture and failure simulations. Calculated results were compared to the experimental data. Good correlations were obtained.

Los Alamos National Laboratory uses a variety of continuous improvement methods, one of which is known as a Continuous Quality Improvement (CQI) Team. The CQI Teams and their results are proving to be effective in improving work processes at Los Alamos National Laboratory. The work reported in this paper is centered around the application of information systems to improve a LANL risk management process. The continuous improvement technique as well as its result should have applicability across DOE M&O Contractor operations.

With diminishing requirements for plutonium, a substantial quantity of this material requires special handling and ultimately, long-term storage. To meet this objective, we at Los Alamos, have been involved in the design of a storage facility with the goal of providing storage capabilities for this and other nuclear materials. This paper presents preliminary basic design data, not for the structure and physical plant, but for the container and arrays which might be configured within the facility, with strong emphasis on criticality safety features.

The Rocky Flats Plant is developing, with active stakeholder a comprehensive planning strategy that will support transition of the Rocky Flats Plant from a nuclear weapons production facility to site cleanup and final disposition. Final disposition of the Rocky Flats Plant materials and contaminants requires consideration of the interrelated nature of sitewide problems, such as material movement and disposition, facility and land use endstates, costs relative risks to workers and the public, and waste disposition. Comparative Risk Analysis employs both incremental risk and cumulative risk evaluations to compare risks from postulated options or endstates. These postulated options or endstates can be various remedial alternatives, or future endstate uses of federal agency land. Currently, there does not exist any approved methodology that aggregates various incremental risk estimates. Comparative Risk Analysis has been developed to aggregate various incremental risk estimates to develop a site cumulative risk estimate. This paper discusses development of the Comparative Risk Analysis methodology, stakeholder participation and lessons learned from these challenges.

A series of experiments with an internal tensor polarized deuterium target in the 2 GeV VEPP-3 electron storage ring in Novosibirsk is being performed. This paper describes the first results for a measurement of the tensor asymmetry in the quasi-elastic (e, e{prime}p) reaction. The found results are compared to a non- relativistic calculation by Arenhoevel and Leidemann, including meson-exchange currents, isobar admixtures and final-state interactions.

The TIARA code has been developed to predict tritium inventory in Li{sub 2}O breeder ceramic and to predict purge exit flow rate and composition under steady-state operating conditions. Inventory predictions are based on models for bulk diffusion, surface desorption, solubility and precipitation. Parameters for these models are determined from the results of laboratory annealing studies on unirradiated and irradiated Li{sub 2}O and from a limited number (2) of inventory data measured after in-reactor purge-flow testing. The remaining inventory data points (18) are used for code validation. In the validation exercise, models and model parameters are fixed to assess how well TIARA predictions agree with data. On the average, the TIARA predictions are in excellent agreement with the inventory data from the following in-reactor tests: EXOTIC-2, SIBELIUS, VOM-15H, CRITIC-1, BEATRIX-II (Phase 1) thin ring, and BEATRIX-II (Phase 1) thick pellet. Thus, TIARA can be used with a reasonable degree of confidence for design analysis over a broad range of fabrication variables and steady-state operating conditions.

The NJOY Nudear Data Processing System has been used to process the Evaluated Nuclear Data File ENDF/B-VI, including all changes through Release 2, into multigroup cross-section libraries that can be used with many different neutron/photon transport codes and into ACE format for use with the MCNP continuous-energy Monte Carlo code. The ENDF-6 format contains a number of new features of interest to reactor physics, and many of the new evaluations take advantage of these features to provided improved data. The changes to the NJOY system required to process these new evaluations are described. The new cross-section libraries have been used to test the performance of ENDF/B-VI for a number of familiar benchmarks. The results are compared to ENDF/B-V results to give an idea of how the new libraries will perform for reactor physics calculations.

The use of laser ignited explosive components has been recognized as a safety enhancement over existing electrical explosive devices (EEDs). Sandia has been pursuing the development of optical ordnance for many years with recent emphasis on developing optical deflagration-to-detonation (DDT) detonators and pyrotechnic actuators. These low energy optical ordnance devices can be ignited with either a semiconductor diode laser, laser diode arrays or a solid state rod laser. By using a semiconductor laser diode, the safety improvement can be made without sacrificing performance since the input energy required for the laser diode and the explosive output are similar to existing electrical systems. The use of higher powered laser diode arrays or rod lasers may have advantages in fast DDT applications or lossy optical environments such as long fiber applications and applications with numerous optical connectors. Recent results from our continued study of optical ignition of explosive and pyrotechnic materials are presented. These areas of investigation can be separated into three different margin categories: (1) the margin relative to intended inputs ( i.e. powder performance as a function of laser input variation), (2) the margin relative to anticipated environments (i.e. powder performance as a function of thermal environment variation), and (3) …

A BKW equation of state in a 1-dimensional hydrodynamic simulation of the cylinder test can be used to estimate the performance of explosives. Using this approach, the novel explosive 1,4-diamino-2,3,5,6-tetrazine-2,5-dioxide (TZX) was analyzed. Despite a high detonation velocity and a predicted CJ pressure comparable to that of RDX, TZX performs relatively poorly in the cylinder test. Theoretical and computational analysis shows this to be the result of a low heat of detonation. A conceptual strategy is proposed to remedy this problem. In order to predict the required heats of formation, new ab initio group equivalents were developed. Crystal structure calculations are also described that show hydrogen-bonding is important in determining the density of TZX and related compounds.

The authors present a model for investigating filamentary structures observed in laser-triggered photoswitches. The model simulates electrons and holes in two-dimensional cylindrical (r-z) geometry, with realistic electron and hole mobilities and field dependent impact ionization. Because of the large range of spatial and temporal scales to be resolved, they are using an explicit approach with fast, direct solution of the field equation. A flux limiting scheme is employed to avoid the time-step constraint due to the short time for resistive relaxation in the high density filament. Self-consistent filament propagation with speeds greater than the carrier drift velocity are observed in agreement with experiments.