Publications

This report describes a capacity planning project for Engineering Information Management (EIM) systems at Sandia National Laboratories. The purpose was to develop a method for predicting the ability of current hardware computer systems to meet future demands and to address the magnitude of required upgrades. Specific activities included the generation and analysis of alternatives, the selection of analytic modeling as the appropriate vehicle, construction and validation of the model, and the development of recommendations.

Ion diode research on Sandia National Laboratories' Particle Beam Fusion Accelerator (PBFA) II has progressed significantly during the past two years as we have operated in the shot-a-day model with well-diagnosed proton and lithium ion diode loads. During this period, we have succeeded in demonstrating efficient proton beam generation and in focusing the beam to a full width at half maximum (FWHM) spot size of 5.2 mm. Power and energy densities equivalent to 5.4 (+0.9, /minus/0.8) TW/cm/sup 2/ and 73 kJ/cm/sup 2/, respectively, on a 6 mm diameter sphere from the full diode were obtained. Tests of ion diode operation with a simple Plasma Opening Switch (POS), opening at a current of 1-2 MA, indicate efficient energy coupling and a rapid turn on of iron when the POS opens. A model of diode operation has been developed which successfully describes the operating impedance of applied-B ion diodes on PBFA II, PBFA I, Proto II, and Proto I. In addition, we have developed the capability to perform particle simulations which have helped to determine optimized insulating magnetic field profiles and anode shapes for efficient ion beam generation and focusing. Lithium ion source experiments on PBFA II have succeeded in delivering 26 kJ of lithium ions to the axis using a field-enhanced LiF ion source. Several active lithium ion sources, which should allow improved lithium began generation and focusing, are now being prepared for testing on PBFA II. 11 refs., 10 figs., 2 tabs.

Personnel at Sandia National Laboratories, the Naval Research Laboratory, Cornell University, and Los Alamos National Laboratory are developing cost effective beams of lithium ions to bridge the energy gap between lasers and underground nuclear explosions in the national Inertial Fusion Program. We plan to probe the threshold for igniting thermonuclear fuel in the laboratory on the Particle Beam Fusion Accelerator II (PBFA II). We have met our April 1, 1989, milestone of 5 trillion watts per square centimeter power density on PBFA II. We wish to adapt the existing Hermes III accelerator at Sandia into a pre-prototype module of the DOE Laboratory Microfusion Facility for military applications in support of the DOE decision in the mid 90s on the best particle beam or laser for the facility. A German-American study concludes that our lithium ion approach offers the lowest cost option for fusion energy. 7 figs.

Superconducting polycrystalline thin films in the Tl-Ca-Bu-Cu-O system have been prepared by electron beam evaporation followed by appropriate sintering and annealing. Transition temperatures to 110 K and critical current densities to 600,000 A/cm/sup 2/ have been attained in oxygen annealed films. However, with only 16 minutes of air sintering and no oxygen anneal, oriented films have been obtained with T/sub c/'s to 107 K and J/sub c/'s to 450,000 A/cm/sup 2/. Single film devices utilizing a parallel array of weak links and a coplanar control line have been fabricated from the films. Oscillators as well as AM and FM modulators operating between 3 and 6 GHz have been demonstrated using this device concept. 24 refs., 4 figs.

A Personnel and Material Tracking System (PMTS) demonstrated at Argonne National Laboratories-West (ANL-W) in 1987 has resulted in the further development of this system. The results of the demonstration indicated immediate potential for the Material Monitoring/Tracking (MM) portion of the system. The MM system provides the separate functions of (1) observing all container movements, (2) authorized access approval,and (3) initiation and receipt of material transfers. All three functions are coordinated through a single computer which is known as the Computer Augmented Material Access (CAMA) computer. The Wireless Alarm Transmission of Container handling (WATCH) system provides Function 1, and the Mobile Accountability Verification Inventory Station (MAVIS) system provides Functions 2 and 3. Faster communications and the expanded and refined software package developed to provide Functions 2 and 3 stands out as the major accomplishment of this project. Increased functionality with enhanced protection against the insider threat in a more friendly operator interface is provided by this software. 3 refs., 2 figs.

In our instrumentation development efforts we find it necessary to be able to evaluate the performance of waveform digitizing systems with sampling rates from a few kilohertz to more than a gigahertz. Our goal has been to develop an integrated system which can provide quantitative results on the performance of systems and subsystems. Here we describe a system which is controlled by a Microvax II with instrumentation control through the IEEE-488 buss. The evaluation procedure is delineated in reference to a Trial Waveform Digitizer Standard generated by the Waveform Measurements and Analysis committee appointed by the Instrumentation and Measurement Society of IEEE. The standard has been recently accepted by the IEEE and will become a published standard. In this work, special focus is given to the accurate measurement of effective-bit performance and differential nonlinearity of waveform digitizers. 3 refs., 8 figs.

This paper presents some simple concepts for fixtures that can be used in two and three-axis vibration testing. Two, two-axis fixtures were built and tested in the laboratory. Test results are shown, and serve to confirm the validity of the concept. Simple methods for extending the concepts for three-axis testing are discussed. 6 refs., 9 figs.

This paper presents a combined analytical and experimental method for establishing a set of equations to evaluate the equivalent forces acting on a structure. The method requires that a finite element model of the structure be established. It further requires that the accelerator responses to the external forces be measured at a number of points on the structure. The equivalent forces established in the analysis are a representation of the actual forces. The equivalent forces concentrate the effects of the external forces at the degrees of freedom where the acceleration responses are measured. 6 refs., 4 figs., 1 tab.

Second harmonic generation was measured for a thin corona-poled film of a dicyanovinyl azo dye incorporated in the side-chain methacrylate polymer. Measurements were performed at a wavelength of 1.58 ..mu..m as a function of incident angle for both p- and s-polarized incident light. From these measurements the form and magnitude of the second harmonic coefficient tensor were determined. The molecular distribution implied by the data is consistent with a thermodynamic potential containing only the dipolar orienting energy acting during poling. We have also demonstrated anomalous-dispersion phase-matched second harmonic generation for the first time using electric field induced second harmonic generation (EFISH) in a liquid solution of Foron Brilliant Blue S-R (FBB). Results are described. 10 refs., 4 figs., 2 tabs.

We report on the first ferroelectric measurements of chemically prepared KNbO/sub 3/ thin films. Polycrystalline KNbO/sub 3/ thin films were fabricated by dip coating substrates with methanolic solutions of potassium hydroxide and niobium ethoxide. Perovskite KNbO/sub 3/ was obtained for both bulk gels and films by using 800/degree/C firing treatments. For films, the intermediate temperature processing schedule was critical for the complete conversion of low temperature phases to perovskite KNbO/sub 3/. Raman spectroscopy and x-ray diffraction analysis confirmed that properly processed films possessed the orthorhombic distortion of the perovskite structure at room temperature. In response to a 1 kHz, sinusoidal field of 300 kV/cm amplitude, we measured the following ferroelectric properties: (1) a remanent polarization of 4.5 ..mu..C/cm/sup 2/, (2) a spontaneous polarization of 8.3 ..mu..C/cm/sup 2/, and (3) a coercive field of 55 kV/cm.

Sandia National Laboratories, in cooperation with industry and other national laboratories, has been benchmarking computer codes (''Structural Code Benchmarking for the Analysis of Impact Response of Nuclear Material Shipping Cask,'' R.E. Glass, Sandia National Laboratories, 1985; ''Sample Problem Manual for Benchmarking of Cask Analysis Codes,'' R.E. Glass, Sandia National Laboratories, 1988; ''Standard Thermal Problem Set for the Evaluation of Heat Transfer Codes Used in the Assessment of Transportation Packages, R.E. Glass, et al., Sandia National Laboratories, 1988) used to predict the structural, thermal, criticality, and shielding behavior of radioactive materials packages. The first step in the benchmarking of the codes was to develop standard problem sets and to compare the results from several codes and users. This step for structural analysis codes has been completed as described in ''Structural Code Benchmarking for the Analysis of Impact Response of Nuclear Material Shipping Casks,'' R.E. Glass, Sandia National Laboratories, 1985. The problem set is shown in Fig. 1. This problem set exercised the ability of the codes to predict the response to end (axisymmetric) and side (plane strain) impacts with both elastic and elastic/plastic materials. The results from these problems showed that there is good agreement in predicting elastic response. Significant differences occurred in predicting strains for the elastic/plastic models. An example of the variation in predicting plastic behavior is given, which shows the hoop strain as a function of time at the impacting end of Model B. These differences in predicting plastic strains demonstrated a need for benchmark data for a cask-like problem. 6 refs., 5 figs.

Obtaining robust phase estimates from phase differences is a problem common to several areas of importance to the optics and signal processing community. Specific areas of application include speckle imaging and interferometry, adaptive optics, compensated imaging, and coherent imaging such as synthetic-aperture radar. The purpose of this paper is to relate the equations describing the phase estimation problem to the general form of elliptic partial differential equations, and illustrate results of reconstructions on large M by N grids using existing, published, and readily available Fortran subroutines. 15 refs., 2 figs.

Vacuum arc remelting (VAR) is the principal secondary melting process used to produce ingots for almost all wrought Alloy 718 applications. We will attempt, with this paper, to summarize our previous work along with other unpublished work as it applies to VAR of Alloy 718. Successful application for a particular alloy/ingot diameter combination is believed to be dependent on achieving quasisteady thermal/solutal conditions at the solidification interfaces. Local thermal environment is strongly influenced by fluid flows which in turn are driven by global temperature gradients (convection) and magnetohydrodynamic (MHD) forces created by the arc's current distribution. Quasisteady conditions are enhanced when the metal vapor arc is stabilized in the diffuse mode where it provides optimal melting efficiency, macrouniform heating, and axisymmetrical fluid flows in the molten pool atop the ingot. Furnace conditions of low ambient gas pressures (<0.01 torr) and short electrode gaps (<10 mm) stabilize the diffuse mode. A transition from convective to magnetically dominant fluid flow occurs in the pool atop the ingot between 6.6 and 7.6 kA for production size ingots. Constricted arcs are stabilized at elevated ambient gas pressures and electrode gaps. Under these arc conditions fluid flows become unsymmetrical with respect to the ingot axis, ''shelf'' forms on portions of the ingot periphery, and melting efficiency is decreased. 19 refs., 13 figs.

Metalloporphyrins have appropriate properties for photosensitizing and catalysts solar energy storage reactions. Fundamental spectroscopic studies of metalloporphyrins and related enzymes that carry out C/sub 1/ chemistry can identify the factors controlling reactivity of the metal complexes. Research has concentrated on mimicking biological methanogenesis through investigation of the enzyme methylreductase, which carries out the final step in the reduction of Co/sub 2/ to methane. Transient and difference Raman spectroscopies were used to investigate the structural features of methylreductase, its nickel-hydrocorphin Cofactor F/sub 430/, and hydrocorphin and porphrin analogs of the active nickel complex. in particular, axial ligation at the nickel site was evaluated under a variety of conditions with the goal of elucidating the mechanism of methane synthesis. Studies of the tin-and antimony-porphyrin photoredox cycles were also carried out as possible solar-driven sources of reductant for biomimetic methane generation. 1 ref., 1 fig.

Packagings for transporting radioactive materials are required to survive exposure to environments. Package designers investigate design and analysis problems through structural and thermal testing of various components or models, using instrumentation to measure physical responses. The acquisition of high quality data from instrumentation is an essential part of the testing activity. To provide this quality of data, we are developing a mobile instrumentation data acquisition system dedicated for use in cask testing. This system is designed to acquire and analyze structural and thermal test data, and to provide leakage measurement capabilities. The mobile instrumentation system is housed in a 13.4m (44-ft) trailer transporter, which is self-contained with air conditioning, heating, and halon fire protection systems. External power from a commercial or motor generator source is line conditioned prior to distribution to the data acquisition equipment inside the trailer, and lightning protection is provided at the point where the measurement devices interface to the data acquisition equipment. This system is capable of performing data analyses and display of the acquired information within thirty minutes after an experiment.

Abstract not provided.

Beginning in April 1985, a working group on heat transfer met under the auspices of the Organization for Economic Cooperation and Development's Committee on Reactor Safety to define a standard problem set which could be used to benchmark codes used to predict cask thermal response. The problem definitions and solutions which resulted from these meetings as described in ''Standard Thermal Problem Set for the Evaluation of Heat Transfer Codes Used in the Assessment of Transportation Packages,'' R.E. Glass, et al., Sandia National Laboratories, 1988 are summarized in this paper. The problems that were defined address each of the major heat transfer mechanisms (conduction, convection, and radiation) that occur in a cask both during normal transport and as a result of the all- engulfing fire scenario. The problems were kept geometrically simple to minimize the resources required to obtain a solution while still addressing actual phenomena. This has resulted in a set of one- and two-dimensional problems. The solutions to this problem set include closed form analytical solutions, experimental data, and consensus of numerical solutions. For each problem the range of numerical solutions are presented. 1 ref., 4 figs., 2 tabs.

Wood is often used as the energy absorbing material in impact limiters, because it begins to crush at low strains, then maintains a near constant crush stress up to nearly 60 percent volume reduction, and there ''locks up.'' Hill has performed tests that show how wood is one of the best absorbers of energy per pound. However, wood's orthotropic behavior for large crush is difficult to model. In the past, analysts have used isotropic foam-like material models for modeling wood. A new finite element technique is presented in this paper that gives a better model of wood crush than the model currently in use. The orthotropic technique is based on locally isotropic, but globally orthotropic (LIGO) assumptions in which alternating layers of hard and soft crushable material are used. Each layer is isotropic; however, by alternating hard and soft thin layer, the resulting global behavior is orthotropic. In the remainder of this paper, the new technique for modeling orthotropic wood crush will be presented. The model is used to predict the crush behavior for different grain orientations of a 5 /times/ 5 inch sample of balsa wood. As an example problem, an impact limiter containing balsa wood as the crushable material is analyzed using both an isotropic model and the alternating layer model. 9 refs., 7 figs.

There has been considerable work over the past few years to study shock-induced solid state chemistry. In the present report, issues raised in the area are reviewed and critical concepts are discussed. The distinctive nature of solid state chemistry compared to liquid and gas phase chemistry is emphasized and material probes suitable for the study of solids are described. In order for solids to react in times less than one microsecond, unusual processes must be initiated in shock compression. Chief among the unique shock processes is the mixing of reactants by the large kinetic energy of shock-compression pulses. Mixing and fluid-like flow can lead to sufficiently intimate contact between reactants to permit complete chemical reaction in the solid state on the time scale of the experiment. Shock-induced solid state chemistry may be described as an unusually intense mechanochemical process. 24 refs., 2 figs.

Solar One is the world's largest central receiver power plant. During the last 4 years the plant availability was 80%, 83%, and 96%, respectively, during hours of sunshine. This reliability is considered to be excellent considering the plant is a first-of-a-kind facility and because it has been subjected to daily cyclic service. In this paper we present the frequencies and causes of the plant outages that occurred. The ten most important causes comprised 72% of the total outage time. Qualitative insights related to the cause and mitigation of these ten are provided. The information presented in this paper will be useful to studies aimed at improving the reliability of future solar central receiver power plants. It is also useful to members of the utility industry who are considering investing in this technology or are considering cyclic operation of conventional power plants. 4 refs., 3 figs.

Several issues have been identified as pertinent to sealing of radioactive waste repositories in bedded salt formations. These issues include: overall seal system functions and strategy for waste isolation; performance requirements for the seal system; need for redundancy; locations of long-term seals in excavations and boreholes; requirements for sealing interbeds and the disturbed rock zone (DRZ) seal stability for the required lifetime; and need for short-term seals in addition to long-term seals. These issues are defined in general terms, and some principles that may be useful in addressing them are presented. Although this presentation derives from experience with bedded salt, it has applicability to domal salt as well.

The following research is proposed: (1) Perform four to six new time-resolved lethality experiments on cadmium at projectile velocities 7 km/s, greater than that of our previous work at 5.2 km/s. The increased velocity will substantially increase the mass percentage of vaporization. Through simulation of these experiments, computer codes can be validated for hypervelocity impact when vaporization occurs. (2) Perform an additional four to six 1-D lethality experiments on zinc. This material undergoes substantial vaporization under the experimental conditions, and would expand our knowledge about the sensitivity of KEW lethality to shock-induced vaporization. (3) Perform two to four ballistic impact experiments with the ballistics gun at Sandia to provide a full validation of computational capabilities used in simulating the 1-D experiments. These experiments would probe phenomenology that is similar to the 1-D experiments, but with multi-dimensional debris propagation. This will extend the confidence in computer modeling to conditions analagous to KEW lethality applications.

A method which is capable of calculating the unsteady flow field around circular-arc bluff bodies of zero thickness is presented. This method utilizes linear vortex panels to model the body surface and a portion of the wake surfaces. Discrete vortices are used to model the remainder of the wake surfaces. Separation is assumed to occur at the sharp edges of the bodies. Numerical results for circular-arc bodies with included angles of less than 180/degree/ are compared with experimental data and found to be in good agreement. 31 refs., 15 figs.

A new recovery parachute system has been designed for the F111 crew escape module (CEM). The system includes a cluster of three 49-ft-dia ringslot-solid parachutes, a Kevlar deployment bag, and an explosively fired drogue gun to deploy the pilot parachute. Tests have been conducted that indicate the parachute system will meet the rate of descent requirement of 25 ft/sec at 5000 ft pressure altitude. To control the drag load developed by the parachutes, a new central reefing/disreefing system has been developed. Since the recovery parachute system is normally deployed crosswind from the CEM, line sail of the suspension lines during early tests was a problem but has been minimized by a dual pilot parachute system. 6 refs., 7 figs.

The possibility of capturing cosmic dust at hypervelocity has been demonstrated in the laboratory and in the unintended Solar Max spacecraft. This technology will enable a comet coma sample return mission and be important for the earth orbital cosmic dust collection mission, i.e., the Space Station Cosmic Dust Collection Facility. Since the only controllable factor in an intact capture of cosmic dust is the capturing medium, characterizing the effectiveness and properties of available capture media would be very important in the development of the technique for capturing hypervelocity cosmic dust intact. We have evaluated various capture underdense media for the relative effectiveness for intact capture. 2 refs., 2 figs.

A vibration test method has been proposed where control is accomplished using extremal control of the force and acceleration at the input to a test item. This proposal is examined with several examples. The method does limit the acceleration input at frequencies where the test item responses tend to be unrealistically large. However, the method's application is not straightforward and care must be taken in the application of the method. 9 refs., 16 figs.

The microstructure, mechanical properties and fracture characteristics of a pulsed Nd:YAG laser weld in a rapid solidification/powder metallurgy (RS/PM) Al-8 wt % Fe-2.3 wt % Mo alloy have been investigated. Results showed the high power density but low total energy input associated with pulsed Nd:YAG laser welding to promote extremely rapid fusion zone (FZ) cooling rates in the vicinity of 10/sup 5//degree/C/s. The weld FZ microstructure consisted primarily of submicron-sized spherical dispersoids in a matrix of fine dendritic-alpha aluminum. A dispersoid-coarsened heat-affected zone (HAZ) was also observed in the boundary between successive, overlapping melt zones. Transverse-weld tensile testing found fracture to occur in the unaffected base metal indicating 100% weld joint efficiency. Longitudinal-weld bend ductility testing revealed fracture initiation and propagation to be associated with the HAZ between successive melt zones at a bend ductility level only marginally below that of the base metal. 12 refs., 7 figs.

A good many words have been spoken and written (some by the present authors) about factoring very large numbers. Therefore, the thrust of this paper is a discussion of how the quadratic sieve algorithm has been adapted to work on a 1024-processor hypercube at Sandia National Laboratories. A brief description of the hypercube, an NCUBE/ten, its idiosyncrasies and its power, as well as some comparisons of timings between numbers factored on the CRAY and on the hypercube, are included. 6 refs., 1 tab.

PBFA II is the first pulsed power accelerator designed and built specifically to produce light ions for driving targets in Sandia National Laboratories inertial confinement fusion program. Recent progress in ion beam generation and focusing has been excellent. Record ion beam intensities have been obtained. Development of an extensive array of diagnostics and advances in the theory of ion diodes have had a major impact on this progress. A summary of recent progress and the present status of the PBFA-II light ion beam fusion program is given. 40 refs., 4 figs.

Amorphous metal foil-wound inductors have been tested as ferromagnetic saturable inductive elements for pulsed-power (multi-terawatt) switching modules in the inertial confinement fusion program at Sandia National Laboratories. In simulated capacitor testing premature dielectric breakdown of thin polyethylene terephthalate film insulation in the inductor windings occurs at considerably below 2500 V. This appears to be due to inadvertant dielectric damage from micro-spikes on the amorphous foil surface. Electron micrographs and dielectric breakdown data illustrate that electrophoretically-applied dielectric coatings, deposited from organic aqueous colloid dispersions, can be used to provide insulating coatings on the foil which provide a 240% improvement (6000 V) in the breakdown strength of wound amorphous foil inductors. The theory and operation of a dedicated electrophoretic continuous coating system is described. The machine was constructed and successfully applied for dielectric coating of amorphous metal foil. Additional possible applications exist for practical dielectric coating of metallic films or foils used in various commercial wound-type capacitor structures. 7 refs., 9 figs.

The influence of coal structure on primary conversions and oil yields in thermolytic extraction with different H-donor and non-H-donor solvents and in dry catalytic hydrogenation has been investigated. Pre-soaking of coal/H-donor solvent slurries at 250/degree/C increased conversions and the level of hydrogen transfer at short contact times (SCT, less than or equal to 10 min), demonstrating studies, prior removal of THF-extractable material (mobile phase) from one bituminous coal actually gave rise to higher conversions to pyridine-solubles for non-donor polynuclear aromatic compounds (PAC), such as naphthalene, phenanthrene and pyrene. These findings highlight the difficulties in relating primary conversions to coal characteristics. In contrast, oil yields have been found to increase broadly with decreasing rank in both H-donor solvent extraction with a process solvent and dry catalytic hydrogenation. However, in SCT tetralin extraction where poor physical contact between coal and solvent exists, neither total conversion nor oil yield correlates with rank. 23 refs., 1 fig., 3 tabs.

We first discuss the progress in linear optics, in particular, the formulation and application of geometrical-optics approximation and its generalization. We then discuss the progress in non-linear optics, in particular, the enhancement of a first-order Freedericksz transition and intrinsic optical bistability in homeotropic and parallel oriented nematic liquid crystal cells. Finally, we discuss the liquid crystal alignment and surface effects on field-induced Freedericksz transition. 50 refs.

Thin silicon nitride (Si/sub 3/N/sub 4/) films are widely used as a dielectric in metal-nitride-oxide-silicon (MNOS) structures for radiation hard non-volatile memories. The retention of charge in these devices depends, among other things, on the chemistry of the films. It has been reported that charge transport in MNOS structures can be reduced by replacing the Si/sub 3/N/sub 4/ film by a silicon oxynitride (SiO/sub x/N/sub y/) film. In order to understand the relationship between chemistry and retention of charge, it is necessary to have a technique that can determine the chemistry of the films as a function of depth. This can be accomplished with Auger electron spectroscopy by using fingerprint spectra for each of the elements and compounds present in the sample. By using classical least-squares techniques, a unique combination of the standard spectra can be found that best fits the unknown spectrum. When this method is repeated for each spectrum in a depth profile, a chemical state depth profile is obtained. The use of this technique to profile oxynitride films where the SiO/sub 2/ content varies between 0 and 12 atomic percent is presented. 6 refs., 7 figs.

The dramatic improvement in silicon concentrator cell efficiency recently demonstrated in university laboratories has had a significant influence on concentrator technology development. This paper briefly describes concentrator field experience, economics, current technology paths, and concludes with a detailed summary of concentrator cell performance. 29 refs., 2 figs., 3 tabs.

When a technology such as solar energy enters the everyday world, the documentation about it must also become part of the technology transfer. The challenge in creating publications about technical subjects for semi-technical people or for popular use is to be both accurate and interesting. The process of creating this documentation should begin by carefully defining the audience and aiming the publication at it. To a large extent, the audience determines both the content and the language that will be used. 2 refs.

In this work, compaction-induced combustion in packed beds of nitrocellulose-based ball propellants is modeled using a multiphase mixture description. This model is applied to conditions simulating low-velocity impact experiments of Sandusky, et. al. (NSWC). A two- stage combustion model is used whereby compressive reaction begins at the compaction front. Subsequent energy release is delayed following an induction rate law based on time-to-reaction experimental data. Given conditions of sufficient energy release and heat transfer, grain burning is initiated when granular surface temperatures exceed decomposition conditions. Numerical solutions of the one-dimensional multiphase conservation equations are obtained using an adaptive finite element method and calculations are compared to experiments investigating various impact loading conditions on the ball propellants TS3659 and WC140. 11 refs., 12 figs., 1 tab.

A study was performed to evaluate the performance of equivalent drag area single parachute systems and cluster parachute systems during the early inflation and initial deceleration phase. Analytical work showed that the cluster system could exhibit better performance during this unsteady aerodynamic phase due to a significant decrease in the apparent mass of air influenced by the parachutes. Two test programs have been performed in support of these assumptions. The first compared systems with parachute drag areas of approximately 750 ft/sup 2/ and a payload of 2400 lbs. The cluster system exhibited increased performance and less susceptibility to parachute collapse due to wake recontact. The second series compared systems with parachute drag areas of approximately 260 ft/sup 2/ with a payload of 800 lbs. The advantages of the cluster system were less apparent but performance was moderately improved. 4 refs., 7 figs.

Time stepping algorithms are often used to solve parabolic and hyperbolic differential equations numerically. These algorithms are generally regarded as sequential in time; that is, the solution on a time level must be known before the computation of the solution at subsequent time levels can start. While this remains true in principle, we demonstrate that it is possible for processors to perform useful work on many time levels simultaneously. Specifically, it is possible for a processor assigned to a ''later'' time level to compute a very good initial guess for the solution based on approximations to the solutions on ''previous'' time levels, thus reducing the time required for solution. The reduction in the solution time can be measured as parallel speedup. We demonstrate two parallel time stepping algorithms that can be used for both linear and nonlinear problems. We compare the two algorithms and discuss their performance in terms of parameters associated with classical time stepping algorithms. 4 refs., 5 tabs.

A general representation approach is described which employs a hierarchy of holes and notches. A matching procedure is also described which allows non-ideal image hierarchies to be matched to class representations. The representation and matching methods are demonstrated on a set of handgun photographs. Examples of handguns which are different in detail are shown to exhibit the same class characteristics, while other similarly shaped objects are correctly distinguished from the handgun class. 6 refs., 8 figs.

The activities involved in establishing an integrated CIM database at Sandia National Laboratories (SNL) are centered around the development of information engineering techniques. Several information engineering techniques were investigated including: top-down/bottom-up, data flow, entity-attribute and binary models. Most of the techniques were rejected because they did not capture all of the required information or they captured information that was not needed in the development of the CIM database. All current modeling activity is required for database development. This paper describes the modeling methodology utilized, the information engineering practices being developed, and a distributed database implementation at SNL. 10 refs., 12 figs.

This paper describes the migration path a company goes through as it moves up the data management learning curve. This migration path is based on four distinct roles for data management in CIM. The first two sections review the justification for CIM and data management. The first section describes the changing competitive environment manufacturers face and how CIM addresses the problems this situation creates. The second section identifies the two key characteristics of a database management system and the benefits provided. The third section identifies and discusses the four roles for data management in CIM. These four roles and their variations provide snapshots of where a company is on the data management learning curve. The fourth section describes the migration path a company goes through as it moves up the learning curve. Although there are similarities, there are some significant differences between this learning curve and the one experienced by MIS as it adopted data management technology. 3 refs.

The fire risk scoping study was sponsored by the US Nuclear Regulatory Commission and performed at Sandia National Laboratories. The study was initiated as a result of previous USNRC-sponsored fire research efforts that had identified certain fire risk issues that had not been addressed in previously completed commercial nuclear power plant fire risk analyses. The specific objectives of this study were: (1) to review and requantify fire risk scenarios from four fire probabilistic risk assessments in light of updated data bases made available as a result of USNRC-sponsored Fire Protection Research Program and updated computer fire modeling capabilities, (2) to identify potentially significant fire risk issues that have not been previously addressed in a fire risk context and to quantify the potential impact of those identified fire risk issues where possible, and (3) to review current fire regulations and plant implementation practices for relevance to the identified unaddressed fire risk issues. 9 refs., 3 tabs.

We are currently investigating a solar-driven photocatalytic process that promises to destroy low concentrations of hazardous organic molecules in large volumes of contaminated groundwater or industrial waste streams. Preliminary results of laboratory-scale screening tests using a model compound, salicylic acid, and titanium dioxide catalyst have shown that no measurable reaction occurs without both uv light and catalyst; no measurable volatilization of the salicylic acid occurs at room temperature; salicylic acid destruction rates depend on catalyst supplier and concentration and on uv light intensity; and some intermediates are being formed and subsequently destroyed. Observed reaction rates are consistent with those observed in an initial pilot-scale solar test of a falling-film reactor, although further testing will be required to quantify the comparison. 10 refs., 5 figs.

The Simplified Analytical Model of Penetration with Lateral Loading (SAMPLL) computer code developed at Sandia National Laboratories has been modified to allow additional penetration capabilities. The new capabilities include the ability to model penetration by other than cylindrical penetrators (flares, tapers, and boattails) and the ability to calculate penetration/perforation of multiple layers of different materials. Additionally, updated soil and rock empirical equations have been added to the model. A broader range of problems can now be modeled more accurately with the modified SAMPLL. 7 refs., 6 figs.

Article VII, paragraphs 8 and 14, of the inspection protocol of the INF Treaty between the US and the USSR provides for the use of radiation detection devices as a verification tool. That is, the Treaty allows the parties to measure the radiation from the radioactive components of nuclear weapons in order to verify that the inspected party is complying with the Treaty. This is the only verification provision in the Treaty that addresses the nuclear components of the relevant weapon systems. Acceptance of and confidence in such measurements is a significant development and similar measurements may be needed for verification of future treaties.

A novel technique is presented for segmenting seismic waveforms. The method produces waveform segments which closely correspond to explosion and earthquake signal onsets as well as additional structure of interest. Noise spikes or glitches are also successfully isolated. The approach uses threshold parameters obtained from human segmentation judgment tests and requires only simple, time domain calculations. 6 refs., 3 figs.

Semiconductor detectors for high energy physics applications offer the potential to obtain accurate particle spacial resolution and on-line data reduction. A significant disadvantage of semiconductor detectors and their associated circuitry however, is their sensitivity to radiation. Fortunately, a sufficient understanding of radiation effects on semiconductor devices exists that some classes of radiation tolerant semiconductor detectors are possible. 11 refs., 11 figs.

The Design Assistance Center (DAC) has developed a database of design, performance, and operating experience for remote photovoltaic (PV) systems. The DAC uses this database to assist potential users in evaluating PV for their specific applications and to accelerate the acceptance of PV as a viable power option for remote applications. 12 refs., 1 fig., 1 tab.

Strong coupling models for the electronic structure of La{sub 2}CuO{sub 4} are derived in two successive stages of renormalization. First, a three-band Hubbard model is derived using a constrained density functional approach. Second, exact diagonalization studies of finite clusters within the three band Hubbard model are used to select and map the low energy spectra onto effective one-band Hamiltonians. At each stage, some observables are calculated and found to be in quantitative agreement with experiment. The final results suggest the following models to be adequate descriptions of the low energy scale dynamics: (1) a spin 1/2 Heisenberg model for the insulating case with nearest neighbor J{approx}130 meV; (2) a t -- t' -- J'' model with nearly identical parameters for the electron and hole doped cases. 14 refs., 2 figs., 1 tab.

A high intensity acoustic test facility has been designed and is under construction at Sandia National Laboratories in Albuquerque, NM. The chamber is designed to provide an acoustic environment of 154dB (re 20 {mu}Pa) overall sound pressure level over the bandwidth of 50 Hz to 10,000 Hz. The chamber has a volume of 16,000 cubic feet with interior dimensions of 21.6 ft {times} 24.6 ft {times} 30 ft. The construction of the chamber should be complete by the summer of 1990. This paper discusses the design goals and constraints of the facility. The construction characteristics are discussed in detail, as are the acoustic performance design characteristics. The authors hope that this work will help others in designing acoustic chambers. 12 refs., 6 figs.