Publications

A technique to integrate a dense, locally non-uniform mesh into finite-difference time-domain (FDTD) codes is presented. The method is designed for the full-wave analysis of multi-material layers that are physically thin, but perhaps electrically thick. Such layers are often used for the purpose of suppressing electromagnetic reflections from conducting surfaces. Throughout the non-uniform local mesh, average values for the conductivity and permittivity are used, where as variations in permeability are accommodated by splitting H-field line integrals and enforcing continuity of the normal B field. A unique interpolation scheme provides accuracy and late-time stability for mesh discontinuities as large as 1000 to 1. Application is made to resistive sheets, the absorbing Salisbury screen, crosstalk on printed circuit boards, and apertures that are narrow both in width and depth with regard to a uniform cell. Where appropriate, comparisons are made with the MoM code CARLOS and transmission-line theory. The hybrid mesh formulation has been highly optimized for both vector and parallel-processing on Cray YMP architectures.

Aerodynamic force and moment measurements and flow visualization results are presented for a hypersonic vehicle configuration at Mach 8. The basic vehicle configuration is a spherically blunted 10{degree} half-angle cone with a slice parallel with the axis of the vehicle. On the slice portion of the vehicle, a flap could be attached so that deflection angles of 10{degree}, 20{degree} and 30{degree} could be obtained. All of the experimental results were obtained in the Sandia Mach 8 hypersonic wind tunnel for laminar boundary layer conditions. Flow visualization results include shear stress sensitive liquid crystal photographs, surface streak flow photographs (using liquid crystals), and spark schlieren photographs and video. The liquid crystals were used as an aid in verifying that a laminar boundary layer existed over the entire body. The surface flow photo-graphs show attached and separated flow on both the leeside of the vehicle and near the flap. A detailed uncertainty analysis was conducted to estimate the contributors to body force and moment measurement uncertainty. Comparisons are made with computational results to evaluate both the experimental and numerical results. This extensive set of high-quality experimental force and moment measurements is recommended for use in the calibration and validation of relevant computational aerodynamics codes.

Contact resistances of greater than 40 milliohms have been associated with hermetic connectors and lightning arrestor connectors (LAC) during routine testing. Empirical analysis demonstrated that the platings could be damaged within several mating cycles. The oxides that formed upon the exposed copper alloy had no significant impact upon contact resistance when the mated contacts were stationary, but effectively disrupted continuity when the mating interfaces were translated. The stiffness of the pin contact was determined to be about five times greater than the socket contact. As the pin contact engages the socket, therefore, the socket spring member deflects and the pin does not deflect. Hence, the pin contact could easily remain centered within the socket cavity in a mated condition, contacting the hemispherical spring at a localized point. Thus the only avenue for electrical conduction is between two contacting curved surfaces-the pin surface and the socket contact dimple surface. This scenario, coupled with the presence of corrosion products at the contacting interface, presents the opportunity for high contact resistances.

The author reports experimental measurements for the argon and oxygen permeability coefficients for the new EPDM material (SR793B-80) used for the environmental o-ring seals of the W88. The results allow the author to refine the argon gas analysis modeling predictions for W88 surveillance units. By comparing early surveillance results (up to four years in the field) with the modeling, the author shows that (1) up to this point in time, leakage past the seals is insignificant and (2) the argon approach should be able to inexpensively and easily monitor both integrated lifetime water leakage and the onset of any aging problems. Finally, the author provides a number of pieces of evidence indicating that aging of the SR793B-80 material will not be significant during the expected lifetime of the W88.

The image blur in a photograph is produced by the exposure of a moving object. Knowing the amount of image blur is important for recording useful data. If there is too much blur, it becomes hard to make quantitative measurements. This report discusses image blur, the parameters used to control it, and how to calculate it.

This report summarizes the purchasing and transportation activities of the Purchasing and Materials Management Organization for Fiscal Year 1992. Activities for both the New Mexico and California locations are included. Topics covered in this report include highlights for fiscal year 1992, personnel, procurements (small business procurements, disadvantaged business procurements, woman-owned business procurements, New Mexico commercial business procurements, Bay area commercial business procurements), commitments by states and foreign countries, and transportation activities. Also listed are the twenty-five commercial contractors receiving the largest dollar commitments, commercial contractors receiving commitments of $1,000 or more, integrated contractor and federal agency commitments of $1,000 or more from Sandia National Laboratories/New Mexico and California, and transportation commitments of $1,000 or more from Sandia National Laboratories/New Mexico and California.

This document is the Operations Manual for the Beneficial Uses Shipping System (BUSS) cask. These operating instructions address requirements; for loading, shipping, and unloading, supplementing general operational information found in the BUSS Safety Analysis Report for Packaging (SARP), SAND 83-0698. Use of the BUSS cask is authorized by Department of Energy (DOE) and Nuclear Regulatory Commission (NRC) for the shipment of special form cesium chloride or strontium flouride capsules.

Two separate Tiger Team assessments were conducted at Sandia National Laboratories (SNL). The first was conducted at the California site in Livermore between April 30, 1990, and May 18, 1990. A second Tiger Team assessment was conducted at the New Mexico site in Albuquerque between April 15 and May 24, 1991. This report is volume two, change one. One purpose of this Action Plan is to provide a formal written response to each of the findings and/or concerns cited in the SNL Tiger Team assessment reports. A second purpose is to present actions planned to be conducted to eliminate deficiencies identified by the Tiger Teams. A third purpose is to consolidate (group) related findings and to identify priorities assigned to the planned actions for improved efficiency and enhanced management of the tasks. A fourth and final purpose is to merge the two original SNL Action Plans for the New Mexico [Ref. a] and California [Ref. b] sites into a single Action Plan as a major step toward managing all SNL ES&H activities more similarly. Included in this combined SNL Action Plan are descriptions of the actions to be taken by SNL to liminate all problems identified in the Tiger Teams` findings/concerns, as well as estimated costs and schedules for planned actions.

Environmental monitoring, earth-resource mapping, and military systems require broad-area imaging at high resolutions. Many times the imagery must be acquired in inclement weather or during night as well as day. Synthetic aperture radar (SAR) provides such a capability. SAR systems take advantage of the long-range propagation characteristics of radar signals and the complex information processing capability of modern digital electronics to provide high resolution imagery. SAR complements photographic and other optical imaging capabilities because of the minimum constrains on time-of-day and atmospheric conditions and because of the unique responses of terrain and cultural targets to radar frequencies. Interferometry is a method for generating a three-dimensional image of terrain. The height projection is obtained by acquiring two SAR images from two slightly differing locations. It is different from the common method of stereoscopic imaging for topography. The latter relies on differing geometric projections for triangulation to define the surface geometry whereas interferometry relies on differences in radar propagation times between the two SAR locations. This paper presents the capabilities of SAR, explains how SAR works, describes a few SAR applications, provides an overview of SAR development at Sandia, and briefly describes the motion compensation subsystem.

Given a planar straight-line graph, we find a covering triangulation whose maximum angle is as small as possible. A covering triangulation is a triangulation whose vertex set contains the input vertex set and whose edge set contains the input edge set. Such a triangulation differs from the usual Steiner triangulation in that we may not add a Steiner vertex on any input edge. Covering triangulations provide a convenient method for triangulating multiple regions sharing a common boundary, as each region can be triangulated independently. As it is possible that no finite covering triangulation is optimal in terms of its maximum angle, we propose an approximation algorithm. Our algorithm produces a covering triangulation whose maximum angle {gamma} is probably close to {gamma}{sub opt}, a lower bound on the maximum angle in any covering triangulation of the input graph. Note that we must have {gamma} {le} 3{gamma}{sub opt}, since we always have {gamma}{sub opt} {ge} {pi}/3 and no triangulation can contain an angle of size greater than {pi}. We prove something significantly stronger. We show that {pi} {minus} {gamma} {ge} ({pi} {minus} {gamma}{sub opt})/6, i.e., our {gamma} is not much closer to {pi} than is {gamma}{sub opt}. This result represents the first nontrivial bound on a covering triangulation`s maximum angle. We require a subroutine for the following problem: Given a polygon with holes, find a Steiner triangulation whose maximum angle is bounded away from {pi}. No angle larger than 8{pi}/9 is sufficient for the bound on {gamma} claimed above. The number of Steiner vertices added by our algorithm and its running time are highly dependent on the corresponding bounds for the subroutine. Given an n-vertex planar straight-line graph, we require O(n + S(n)) Steiner vertices and O(n log n + T(n)) time, where S(n) is the number of Steiner vertices added by the subroutine and T(n) is its running time for an O(n)-vertex polygon with holes.

We have previously shown that charge carriers are generated by exciton-exciton annihilation in solid films of poly(di-n-hexylsilane). Using this phenomenon we show that the exciton-exciton annihilation rate constant γ at ambient temperature is not a function of the photon energy used to create the excitons even at energies well out into the long wavelength tail of the exciton absorption band. We also show that the excitons remain highly mobile throughout their 600 ps lifetime and that they diffuse distance comparable to the crystallite size in the film. The value of γ obtained in these studies is in excellent agreement with that obtained previously in fluorescence intensity studies. © 1993.

One proven method of evading the detection of a nuclear test is to decouple the explosion with a large air-filled cavity. Past tests have shown it is possible to substantially reduce the seismic energy emanating from a nuclear explosion by as much as two, orders of magnitude. The problem is not whether it can be done; the problem is the expense involved in mining a large cavity to fully decouple any reasonable size test. It has been suggested that partial decoupling may exist so some fraction of decoupling may be attained between factors of 1 to 100. MISTY ECHO and MINERAL QUARRY are two nuclear tests which were instrumented to look at this concept. MISTY ECHO was a nuclear explosion conducted in an 11 m hemispherical cavity such that the walls were over driven and reacted in a non-linear manner. MINERAL QUARRY was a nearby tamped event that is used as a reference to compare with MISTY ECHO. The scaled cavity radius of MISTY ECHO was greater than 2m/kt[sup l/3]. Both of these tests had free-field accelerometers located within 400 m of their respective sources. Analysis of surface ground motion is inconclusive on the question of partial decoupling. This is due to the difference in medium properties that the ray paths take to the surface. The free-field configuration alleviates this concern. The analysis consists of cube-root signal MINERAL QUARRYs signal to MISTY ECHO's yield and calculating the ratio of the Fourier amplitudes of both the acceleration and the reduced displacement potentials. The results do not indicate the presence of partial decoupling. In fact, there is a coupling enhancement factor of 2.

Hazardous operations which involve the dextrous manipulation of dangerous materials in the field have, in the past, been completed by technicians. Use of humans in such hazardous operations is under increased scrutiny due to high costs and low productivity associated with providing protective clothing and environments. Remote systems are needed to accomplish many tasks such as the clean up of waste sites in which the exposure of personnel to radiation, chemical, explosive, and other hazardous constituents is unacceptable. Traditional remote manual field operations have, unfortunately, proven to have very low productivity when compared with unencumbered human operators. Recent advances in the integration of wars and computing into the control of remotely operated equipment have shown great promise for reducing the cost of remote systems while providing faster and safer remote systems. This paper discusses applications of such advances to remote field operations.

Multiple tracer techniques were used to estimate recharge rates through unsaturated alluvium beneath the Greater Confinement Disposal site, a waste disposal site located in Frenchman Flat, on the Nevada Test Site. Three tracers of soil water movement -- meteoric chloride, stable isotopes of water, and cosmogenic chlorine-36 -- yielded consistent results indicating that recharge rates were negligible for the purpose of performance assessment at the site.

This report describes work performed for the development of a fiber-optic shock position sensor used to measure the location of a shock front in the neighborhood of a nuclear explosion. Such a measurement would provide a hydrodynamic determination of nuclear yield. The original proposal was prompted by the Defense Nuclear Agency`s interest in replacing as many electrical sensors as possible with their optical counterparts for the verification of a treaty limiting the yield of a nuclear device used in underground testing. Immunity to electromagnetic pulse is the reason for the agency`s interest; unlike electrical sensors and their associated cabling, fiber-optic systems do not transmit to the outside world noise pulses from the device containing secret information.

This paper describes the connection between mechanical degradation of common cable materials in radiation and elevated temperature environments and density increases caused by the oxidation which leads to this degradation. Two techniques based on density changes are suggested as potential non-destructive evaluation (NDE) procedures which may be applicable to monitoring the mechanical condition of cable materials in power plant environments. The first technique is direct measurement of density changes, via a density gradient column, using small shavings removed from the surface of cable jackets at selected locations. The second technique is computed X-ray tomography, utilizing a portable scanning device.

We technologists generally only address risk magnitudes in our analyses, although other studies have found nineteen additional dimensions for the way the public perceives risk. These include controllability, voluntariness, catastrophic potential, and trust in the institution putting forth the risk. We and the geneml public use two different languages, and to understand what their concerns are, we need to realize that the culture surrounding nuclear weapons is completely alien to the general public. Ultimately, the acceptability of a risk is a values question, not a technical question. For most of the risk dimensions, the public would perceive no significant difference between using oralloy and plutonium. This does not mean that the suggested design change should not be proposed, only that the case for, or against, it be made comprehensively using the best information available today. The world has changed: the ending of the cold war has decreased the benefit of nuclear weapons in the minds of the public and the specter of Chernobyl has increased the perceived risks of processes that use radioactive materials. Our analyses need to incorporate the lessons pertinent to this newer world.

This is the final report for a study performed for the 1992 LDRD spaceborne SAR (Synthetic Aperture Radar) study. This report presents an overview of some of the issues that must be considered for design and implementation of a SAR on a spaceborne platform. The issues addressed in this report include: a survey of past, present, and future spaceborne SARs; pulse-repetition frequency (PRF); general image processing issues; transmitter power requirements; the ionosphere; antennas; two case studies; and an appendix with a simplified presentation on geometry and orbits.

Damage induced during electron-beam metallization results in a three-order-of-magnitude increase in the generation rate of bulk GaAs. The damage appears to be radiation induced, with low-energy electrons being the most likely from p{sup +}-i-n-i-p{sup +}-GaAs layers damaging mechanism.

This report describes the design, development, manufacturing processes, acceptance equipment, test results, and conclusions for the SA3581/MC4196 LAC program. Four development groups (Identified as Groups 1 through 3 and a Proof of Development Build) provided the evaluation criteria for the PPI/TMS production units.

An ever increasing demand for highly rugged, miniature AT strip resonators prompted the development of a resonator package for use in high-g shock applications. This package, designed and developed by Statek Corporation, is based on the package configuration currently being used by Statek for commercial devices. This report describes the design intent, component characteristics, and evaluation test results for this device.

A temperature between 400 and 500 and a pressure between 40 MPa and 160 MPa were indicated by a two-factor, three-level factorial experiment for diffusion bonding of molybdenum sheet substrates. These substrates were sputter ion plated with palladium (0.5 {mu}m) and silver (10 {mu}m) films on the mating surfaces, with the silver used as a bonding interlayer. The palladium acted as an adhesive layer between the silver film and molybdenum substrate. The silver diffusion bonds that resulted were qualitatively characterized at the interfacial regions, and bonds with no visible interface were obtained at 750OX magnification. Correlations were obtained for voids found optically at the silver/silver bonding interface and colored image maps, illustrating bond quality, produced by nondestructive ultrasonic imaging. Above 160 MPa, the bonding process produces samples with a nonuniform load distribution. These samples contained regions with gaps and well-bonded regions at the silver/silver interface, and all had macroscopic deformation of the silver films.

Salford Electrical Instruments, Ltd., and the General Electric Company`s Hirst Research Centre, under contract to the United Kingdom`s (UK) Ministry of Defence, developed a radiation-hard, leadless chip-carrier-packaged oscillator/divider. Two preproduction clocks brought to Sandia National Laboratories (SNL) by a potential SNL customer underwent mechanical and thermal environmental evaluation. Because of the subsequent failure of one device and the deteriorating condition of another device, the devices were not subjected to radiation tests. This report describes the specifics of the environmental evaluation performed on these two clocks and the postmortem analysis of one unit, which ultimately failed. Clock startup time versus temperature studies were also performed and compared to an SNL-designed clock having the same fundamental frequency.

High speed flash radiography has been used to record phenomena that occur during rapid dynamic events. The events are difficult, if not impossible, to record by other means due to the speed of the event or the obscuration associated with it. To eliminate the motion blur of objects moving at high speeds it is necessary to have extremely short exposure times. This short exposure time requires the use of high speed intensifying screens and high speed x-ray film to record the radiographic image. Technicians who use flash x-rays have to depend on recommendations from present and former flash x-ray users for film and screen selection. The film and screen industry has made many changes in the last few years. It is not uncommon to find that the particular film or screen used in the past is no longer manufactured. This paper will describe some of the films and screens that are currently used for testing. It will also describe the optimum experimental setup used to obtain the best images.

The Modal Group at Sandia National Laboratories performs a variety of tests on structures ranging from weapons systems to wind turbines. The desired number of data channels for these tests has increased significantly over the past several years. Tests requiring large numbers of data channels makes roving, accelerometers impractical and inefficient. The Modal Lab has implemented a method in which the test unit is fully instrumented before any data measurements are taken. This method uses a 16 channel data acquisition system and a mechanical switching setup to access each bank of accelerometers. A data base containing all transducer sensitivities, location numbers, and coordinate information is resident on the system enabling quick updates for each data set as it is patched into the system. Ibis method has reduced test time considerably and is easily customized to accommodate data acquisition systems with larger channel capabilities.

A new class of inorganic ion exchange materials that can separate low parts per million level concentrations of Cs{sup +} from molar concentrations of Na{sup +} has recently been developed as a result of a collaborative effort between Sandia National Laboratories and Texas A&M University. The materials, called crystalline silicotitanates, show significant potential for application to the treatment of aqueous nuclear waste solutions, especially neutralized defense wastes that contain molar concentrations of Na{sup +} in highly alkaline solutions. In experiments with alkaline solutions that simulate defense waste compositions, the crystalline silicotitanates exhibit distribution coefficients for Cs{sup +} of greater than 2,000 ml/g, and distribution coefficients greater than 10,000 for solutions adjusted to a pH between 1 and 10. Additionally, the crystalline silicotitanates were found to exhibit distribution coefficients for Pu and Sr{sup 2+} of greater than 2,000 and 100,000 respectively. Development of these materials for use in processes to treat defense waste streams is currently being pursued.

The effects of the midgap-level interface trap density and net oxide charge on the total-dose gain degradation of a bipolar transistor are separately identified. The superlinear dose dependence of the excess base current is explained.

MOS total-dose response is shown to depend strongly on transistor gate length. Simple scaling models cannot predict short-channel device response from long-channel results. Hardness assurance implications are discussed for weapon and space environments.

We have studied intrinsic free-carrier recombination in a variety of GaAs structures, including: OMVPE- and MBE-prepared GaAs/Al{sub x}Ga{sub 1-x}As double heterostructures, Na{sub 2}S passivated GaAs structures and bare GaAs structures. We find OMVPE prepared structures are superior to all of these other structures with 300 K lifetimes of {approximately} 2.5 {mu}s and negligible nonradiative interface and bulkrecombination, and thus are truly surface-free (S < 40 cm/s). Moreover, we observe systematic trends in optical properties versus growth conditions. Lastly, we find that the presence of free-exciton recombination in the low-temperature photoluminescence spectra is a necessary but not sufficient condition for optimal optical properties (i.e. long minority-carrier lifetimes).

Sandia National Laboratories (SNL) is conducting several research programs to help develop validated methods for the prediction of the ultimate pressure capacity, at elevated temperatures, of light water reactor (LWR) containment structures. To help understand the ultimate pressure of the entire containment pressure boundary, each component must be evaluated. The containment pressure boundary consists of the containment shell and many access, piping, and electrical penetrations. The focus of the current research program is to study the ultimate behavior of flexible metal bellows that are used at piping penetrations. Bellows are commonly used at piping penetrations in steel containments; however, they have very few applications in concrete (reinforced or prestressed) containments. The purpose of piping bellows is to provide a soft connection between the containment shell and the pipe are attached while maintaining the containment pressure boundary. In this way, piping loads caused by differential movement between the piping and the containment shell are minimized. SNL is conducting a test program to determine the leaktight capacity of containment bellows when subjected to postulated severe accident conditions. If the test results indicate that containment bellows could be a possible failure mode of the containment pressure boundary, then methods will be developed to predict the deformation, pressure, and temperature conditions that would likely cause a bellows failure. Results from the test program would be used to validate the prediction methods. This paper provides a description of the use and design of bellows in containment piping penetrations, the types of possible bellows loadings during a severe accident, and an overview of the test program, including available test results at the time of writing.

The Department of Energy`s Nevada Field Office has disposed of a small quantity of high activity and special case wastes using Greater Confinement Disposal facilities in Area 5 of the Nevada Test Site. Because some of these wastes are transuranic radioactive wastes, the Environmental Protection Agency standards for their disposal under 40 CFR Part 191 which requires a compliance assessment. In conducting the 40 CFR Part 191 compliance assessment, review of the Greater Confinement Disposal inventory revealed potentially land disposal restricted hazardous wastes. The regulatory options for disposing of land disposal restricted wastes consist of (1) treatment and monitoring, or (2) developing a no-migration petition. Given that the waste is already buried without treatment, a no-migration petition becomes the primary option. Based on a desire to minimize costs associated with site characterization and performance assessment, a single approach has been developed for assessing compliance with 40 CFR Part 191, DOE Order 5820.2A (which regulates low-level radioactive wastes contained in Greater Confinement Disposal facilities) and developing a no-migration petition. The approach consists of common points of compliance, common time frame for analysis, and common treatment of uncertainty. The procedure calls for conservative bias of modeling assumptions, including model input parameter distributions and adverse processes and events that can occur over the regulatory time frame, coupled with a quantitative treatment of data and parameter uncertainty. This approach provides a basis for a defensible regulatory decision. In addition, the process is iterative between modeling and site characterization activities, where the need for site characterization activities is based on a quantitative definition of the most important and uncertain parameters or assumptions.

The first portion of this paper proposes a method of fabricating a material whose modulus can be changed substantially through the application of a specified stimulus. The particular implementation presented here indirectly exploits the large deformation associated with shape memory alloys to achieve the desired modulation of stiffness. The next portion of this paper discusses a class of vibration problems for which such materials have a serious potential for vibration suppression. These are problems, such as the spinning up of rotating machinery, in which the excitation at any time lies within a narrow frequency band, and that band moves through the frequency spectrum in a predictable manner. Finally, an example problem is examined and the utility of this approach is discussed.

An element based finite control volume procedure is applied to the solution of ablation problems for 2-D axisymmetric geometries. A mesh consisting of four node quadrilateral elements was used. The nodes are allowed to move in response to the surface recession rate. The computational domain is divided into a region with a structured mesh with moving nodes and a region with an unstructured mesh with stationary nodes. The mesh is costrained to move along spines associated with the original mesh. Example problems are presented for the ablation of a realistic nose tip geometry exposed to aerodynamic heating from a uniform free stream environment.

The paper gives some of the highlights of a panel discussion on surface diffusion held Monday, November 30, 1992 at the Fall MRS Meeting in Boston, Massachusetts. Four invited speakers discussed computer modeling techniques and scanning tunneling microscopy experiments that have been used to provide new understanding of the atomistic processes that occur at surfaces. We present a summary of each of the invited talks, indicate other presentations on surface diffusion in this proceedings, and provide a transcript of the two discussion sessions.

During the past few years, methods have been developed for quantifying and analyzing common cause failures (CCFs). These methods have outpaced current data collection activities. This document discusses the collection and documentation of failure events at nuclear power plants with respect to these new CCFs methods. The report concentrates on the information necessary to improve the parameter estimates for both independent and dependent events in probabilistic risk assessments (PRAS) and alludes to the fact that the same information can be used to enhance other nuclear power plant activities. Several existing data bases are reviewed as to their adequacy for these new CCF methods, and areas where information is lacking, either because certain information is simply not required to be reported or because required information was simply not reported, are identified. Finally, data needs identified from recent PRAs are discussed.

Lighting protection systems (LPSs) for explosives handling and storage facilities have long been designed similarly to those will for more conventional facilities, but their overall effectiveness in controlling interior electromagnetic (EM) environments has still not been rigorously assessed. Frequent lightning-caused failures of a security system installed in earth-covered explosives storage structures prompted the U.& Army and Sandia National Laboratories to conduct a program to determine quantitatively the EM environments inside an explosives storage structure that is struck by lightning. These environments were measured directly during rocket-triggered lightning (RTL) tests in the summer of 1991 and were computed using linear finite-difference, time-domain (FDTD) EM solvers. The experimental and computational results were first compared in order to validate the code and were also used to construct bounds for interior environments corresponding to seven incident lightning flashes. The code insults were also used to develop simple circuit models for the EM field behavior-a process that insulted in a very simple and somewhat surprising physical interpretation of the structure`s response that has significant practical and economic implications for design, construction, and maintenance of such facilities.

A panel discussion on interface roughness was held at the Fall 1992 Materials Research Society meeting. We present a of results presented by the invited speakers on the application and interpretation of X-ray reflectivity, atomic force microscopy (AFM), scanning tunneling microscopy (STM), photoluminescence and transmission electron microscopy.

A safety system has been designed and constructed to mitigate the asphyxiation and low temperature hazards presented by the distribution and usage of cryogenic liquids in work spaces at Sandia National Laboratories. After identifying common accident scenarios, the CRYOFACS (Cryogenic Fail-Safe Control System) unit was designed, employing microprocessor technology and software that can be easily modified to accommodate varying laboratory requirements. Sensors have been incorporated in the unit for the early detection of accidental releases or overflows of cryogenic liquids. The CRYOFACS design includes control (and shutdown) of the cryogen source upon error detection, and interfaces with existing oxygen monitors, in common use at Sandia Labs, to provide comprehensive protection for both personnel and property.

The Greater Confinement Disposal (GCD) facility was established by the Nevada office of the Department of Energy (DOE) in Area 5 at the Nevada Test Site for containment of waste inappropriate for shallow land burial. Some transuranic (TRU) waste has been disposed of at the GCD facility, and compliance of this disposal system with Environmental Protection Agency (EPA) regulations 40 CFR 191 must be evaluated by performance assessment calculations. We have adopted an iterative approach where performance assessment results guide site data collection which in turn influences the parameters and models used in performance assessment. The first iteration was based upon readily available data. The first iteration indicated that the GCD facility would likely comply with 40 CFR 191 and that the downward recharge rate had a major influence on the results. As a result, a site characterization project was initiated to study recharge in Area 5 by use of three environmental tracers. This study resulted in the conclusion that recharge was extremely small, if not negligible. Thus, downward advection to the water table is no longer considered a viable release pathway, leaving upward liquid diffusion as the sole release pathway. This second performance assessment iteration refined the upward pathway models and parameters. The results of the performance assessment using these models still indicate that the GCD site is likely to comply with all sections of 40 CFR 191.

We have developed a method for generating chromate-free corrosion resistant coatings on aluminum alloys using a process procedurally similar to standard chromate conversion. These coatings provide good corrosion resistance on 6061-T6 and 1100 A1 under salt spray testing conditions. The resistance of the new coating is comparable to that of chromate conversion coatings in four point probe tests, but higher when a mercury probe technique is used. Initial tests of paint adhesion, and under paint corrosion resistance are promising. Primary advantage of this new process is that no hazardous chemicals are used or produced during the coating operation.

A method is described to characterize shocks (transient time histories) in terms of the Fourier energy spectrum and the temporal moments of the shock passed through a contiguous set of bandpass filters. This method is compared for two transient time histories with the more conventional methods of shock response spectra (SRS) and a nonstationary random characteristic.

Qualitatively different trends in postirradiation electrical response are observed in MOS devices after very long (up to 2.75-year) switched-bias bakes. A revised defect nomenclature is introduced, and implications for MOS defect models are discussed.

La{sub 2-x}Sr{sub x}CuO{sub 4+{delta}} with x = 0.01, 0.025, 0.050, 0.10 and 0.16 and excess oxygen {delta} incorporated by high-pressure O{sub 2} anneals. These compounds were examined using time-of-flight neutron diffraction data. Various models were fit by Rietveld least-squares refinement, with the maximum amount of {delta} being only of the order of 10 standard deviations. {delta} is largest for x near 0, is zero for x = 0.10 and is intermediate for x = 0.16. Only the sample with x = 0.01 is found to phase separate distinctly into a nearly stoichiometric phase with {delta} {approx} 0 and an oxygen-rich superconducting phase as the temperature is lowered. Coincidence of phase separation and Neel temperature strongly suggests that the phase separation is driven by free energy provided by long-range antiferromagnetic ordering in the nearly stoichiometric, weakly Sr-doped La{sub 2-x}Sr{sub x}CuO{sub 4}. The excess oxygen stoichiometry shows that at low values of x, hole doping is provided primarily by the excess oxygen, and is enhanced substantially by phase separation. At larger values of x, excess oxygen is no longer incorporated, and hole doping is provided by the substitution of Sr{sup +2} for La{sup +3}.

The US Nuclear Regulatory Commission (NRC) is investigating the performance of containments subject to severe accidents. This work is being performed by Sandia National Laboratories (SNL). In 1987, a 1:6-scale Reinforced Concrete Containment (RCC) model was tested to failure. The failure mode was a liner tear. As a result, a separate effects test program has been conducted to investigate liner tearing. This paper discusses the design of test specimens and the results of the testing. The post-test examination of the 1:6-scale RCC model revealed that the large tear was not an isolated event. Other small tears in similar locations were also discovered. All tears occurred near the insert-to-liner transition which is also the region of closest stud spacing. Also, all tears propagated vertically, in response to the hoop strain. Finally, all tears were adjacent to a row of studs. The tears point to a mechanism which could involve the liner/insert transition, the liner anchorage, and the material properties. The separate effects tests investigated these effects. The program included the design of three types of specimens with each simulating some features of the 1:6-scale RCC model. The specimens were instrumented using strain gages and photoelastic materials.

The problem of constructing trees given a matrix of interleaf distances is motivated by applications in computational evolutionary biology and linguistics. The general problem is to find an edge-weighted tree which most closely approximates the distance matrix. Although the construction problem is easy when the tree exactly fits the distance matrix, optimization problems under all popular criteria are either known or conjectured to be NP-complete. In this paper we consider the related problem where we are given a partial order on the pairwise distances, and wish to construct (if possible) an edge-weighted tree realizing the partial order. In particular we are interested in partial orders which arise from experiments on triples of species, which determine either a linear ordering of the three pairwise distances (called Total Order Model or TOM experiments) or only the pair(s) of minimum distance apart (called Partial Order Model or POM experiments). The POM and TOM experimental model is inspired by the model proposed by Kannan, Lawler, and Warnow for constructing trees from experiments which determine the rooted topology for any triple of species. We examine issues of construction of trees and consistency of TOM and POM experiments, where the trees may either be weighted or unweighted. Using these experiments to construct unweighted trees without nodes of degree two is motivated by a similar problem studied by Winkler, called the Discrete Metric Realization problem, which he showed to be strongly NP-hard. We have the following results: Determining consistency of a set of TOM or POM experiments is NP-Complete whether the tree is weighted or constrained to be unweighted and without degree two nodes. We can construct unweighted trees without degree two nodes from TOM experiments in optimal O(n{sup 3}) time and from POM experiments in O(n{sup 4}) time.

Semiconductor ring lasers are being developed for use as direct-waveguide-coupled sources for photonic integrated circuits. This report describes the results of our research and development of this new class of diode lasers. We have fabricated and characterized semiconductor ring lasers which operate continuous-wave at room temperature with a single-frequency output of several milliwatts. Our work has led to an increased understanding of the operating behavior of these lasers and to the development of two new types of advanced devices. The interferometric ring diode laser uses a coupled-cavity structure to improve the level of single-frequency performance. And, the unidirectional ring diode laser uses an active crossover waveguide to promote lasing in a single ring direction with up to 96% of the output emitted in the preferred lasing direction.

Results from fundamental investigations of low-temperature plasma systems were used to improve chamber-to-chamber reproducibility and reliability in commercial plasma-etching equipment. The fundamental studies were performed with a GEC RF Reference Cell, a laboratory research system designed to facilitate experimental and theoretical studies of plasma systems. Results and diagnostics from the Reference Cell studies were then applied to analysis and rectification of chamber-to-chamber variability on a commercial, multichamber, plasma reactor. Pertinent results were transferred to industry.

Compression seals are commonly used in electronic components. Because glass has such a low fracture toughness, tensile residual stresses must be kept low to avoid crackS. N. Burchett analyzed a variety of compression pin seals to identify mechanically optimal configurations when work hardened Alloy 52 conductor pins are sealed in a 304 stainless steel housing with a Kimble TM-9 glass insulator. Mechanical property tests on Alloy 52, have shown that the heat treatments encountered in a typical glass sealing cycle are capable of annealing the Alloy 52 pins, increasing ductility and lowering the yield strength. Since most seal analyses are routinely based on unannealed Alloy 52 properties, a limited study has been performed to determine the design impact of lowering the yield strength of the pins in a typical compression seal. Thermal residual stresses were computed in coaxial compression seals with annealed pins and the results then were used to reconstruct design guidelines following the procedures employed by Miller and Burchett. Annealing was found to significantly narrow the optimal design range (as defined by a dimensionless geometric parameter). The Miller-Burchett analyses which were based on very coarse finite element meshes and a 50 ksi yield strength fortuitously predicted an overly conservative design range that is a subset of the narrow design window prevalent when the yield strength is assumed to be 34 ksi. This may not remain true for lower yield strengths. The presence of pin wetting was shown to exacerbate the glass stress state. The time is right to develop a modern and enhanced set of design guidelines which could address new material systems, three dimensional geometries, and viscoelastic effects.

With ever increasing processor and memory speeds, new methods to overcome the ``I/O bottleneck`` need to be found. This is especially true for massively parallel computers that need to store and retrieve large amounts of data fast and reliably, to fully utilize the available processing power. We have designed and implemented a parallel file system, that distributes the work of transferring data to and from mass storage, across several I/O nodes and communication channels. The prototype parallel file system makes use of the existing single threaded file system of the Sandia/University of New Mexico Operating System (SUNMOS). SUNMOS is a joint project between Sandia National Laboratory and the University of New Mexico to create a small and efficient OS for Massively Parallel (MP) Multiple Instruction, Multiple Data (MIMD) machines. We chose file striping to interleave files across sixteen disks. By using source-routing of messages we were able to increase throughput beyond the maximum single channel bandwidth the default routing algorithm of the nCUBE 2 hypercube allows. We describe our implementation, the results of our experiments, and the influence this work has had on the design of the Performance-oriented, User-managed, Messaging Architecture (PUMA) operating system, the successor to SUNMOS.

An automatic phase identification system that employs a neural network approach to classifying seismic event phases is described. Extraction of feature vectors used to distinguish the different classes is explained, and the design and training of the neural networks in the system are detailed. Criteria used to evaluate the performance of the neural network approach are provided.

Satellite electronics may be subjected to a large fluence of protons from the Van Allen belt and from solar flares. To determine if unhardened electronics will survive a radiation environment, the total ionizing dose and displacement damage to the electronics must be determined. Several computer codes are available for modeling proton transport, ranging in complexity for a very-efficient straight-line approximation to general-geometry time-dependent Monte Carlo transport, with corresponding increase in computer run time. For most satellite applications, neutrons can be neglected in the analysis. However, neutrons may be important for modeling heavily shielded compartments for personnel and electronics.

This report describes the activities and results of an LDRD entitled Sensor Based Process Control. This research examined the needs of the plating industry for monitor and control capabilities with particular emphasis on water effluent from rinse baths. A personal computer-based monitor and control development system was used as a test bed.

A large-scale brine inflow test was conducted 655 m below ground surface in a cylindrical test room at the Waste Isolation Pilot Plant (WIPP). This test was the first large-scale WIPP test that allowed periodic access to a sealed, monitored excavation. The test was designed to characterize the environment within the sealed test room (Room Q) and to examine the surrounding host rock to quantify such characteristics as near-surface resistivity and permeability in the formation surrounding the room. Testing began with room boring in July 1989. Data in this report were collected from the time of test start-up through November 25, 1991. Relative humidity, barometric pressure, and temperature were measured in the sealed environment of the test room. Formation closure rates and electrical resistance of the formation close to the room surface were measured to determine the response of the host rock around Room Q. Brine was collected periodically to quantify the amount of inflow from large-scale openings. Results of the measurements are presented in a series of graphs. This report also describes the features of the test

Pore-pressure and fluid-flow tests were performed in 15 boreholes drilled into the bedded evaporites of the Salado Formation from within the Waste Isolation Pilot Plant (WIPP). The tests measured fluid flow and pore pressure within the Salado. The boreholes were drilled into the previously undisturbed host rock around a proposed cylindrical test room, Room Q, located on the west side of the facility about 655 m below ground surface. The boreholes were about 23 m deep and ranged over 27.5 m of stratigraphy. They were completed and instrumented before excavation of Room Q. Tests were conducted in isolated zones at the end of each borehole. Three groups of 5 isolated zones extend above, below, and to the north of Room Q at increasing distances from the room axis. Measurements recorded before, during, and after the mining of the circular test room provided data about borehole closure, pressure, temperature, and brine seepage into the isolated zones. The effects of the circular excavation were recorded. This data report presents the data collected from the borehole test zones between April 25, 1989 and November 25, 1991. The report also describes test development, test equipment, and borehole drilling operations.

The multiplication of a vector by a matrix is the kernel computation of many algorithms in scientific computation. A fast parallel algorithm for this calculation is therefore necessary if one is to make full use of the new generation of parallel supercomputers. This paper presents a high performance, parallel matrix-vector multiplication algorithm that is particularly well suited to hypercube multiprocessors. For an n x n matrix on p processors, the communication cost of this algorithm is O(n/{radical}p + log(p)), independent of the matrix sparsity pattern. The performance of the algorithm is demonstrated by employing it as the kernel in the well-known NAS conjugate gradient benchmark, where a run time of 6.09 seconds was observed. This is the best published performance on this benchmark achieved to date using a massively parallel supercomputer.

Radioactive spent fuel assemblies are a source of hazardous waste that will have to be dealt with in the near future. It is anticipated that the spent fuel assemblies will be transported to disposal sites in spent fuel transportation casks. In order to design a reliable and safe transportation cask, the maximum cladding temperature of the spent fuel rod arrays must be calculated. A comparison between numerical calculations using commercial thermal analysis software packages and experimental data simulating a horizontally oriented spent fuel rod array was performed. Twelve cases were analyzed using air and helium for the fill gas, with three different heat dissipation levels. The numerically predicted temperatures are higher than the experimental data for all levels of heat dissipation with air as the fill gas. The temperature differences are 4{degree}C and 23{degree}C for the low heat dissipation and high heat dissipation, respectively. The temperature predictions using helium as a fill gas are lower for the low and medium heat dissipation levels, but higher at the high heat dissipation. The temperature differences are 1{degree}C and 6{degree}C for the low and medium heat dissipation, respectively. For the high heat dissipation level, the temperature predictions are 16{degree}C higher than the experimental data. Differences between the predicted and experimental temperatures can be attributed to several factors. These factors include experimental uncertainty in the temperature and heat dissipation measurements, actual convection effects not included in the model, and axial heat flow in the experimental data. This work demonstrates that horizontally oriented spent fuel rod surface temperature predictions can be made using existing commercial software packages. This work also shows that end effects will be increasingly important as the amount of dissipated heat increases.

This bulletin discusses the following: decontamination of polluted water by using a photocatalyst to convert ultraviolet energy into electrochemical energy capable of destroying organic waste and removing toxic metals; monitoring oil spills with SAR by collecting data in digital form, processing the data, and creating digital images that are recorded for post-mission viewing and processing; revitalization of a solar industrial process heat system which uses parabolic troughs to heat water for foil production of integrated circuits; and an electronic information system, EnviroTRADE (Environmental Technologies for Remedial Actions Data Exchange) for worldwide exchange of environmental restoration and waste management information.

Sandia is a DOE multiprogram engineering and science laboratory with major facilities at Albuquerque, New Mexico, and Livermore, California, and a test range near Tonapah, Nevada. We have major research and development responsibilities for nuclear weapons, arms control, energy, the environment, economic competitiveness, and other areas of importance to the needs of the nation. Our principal mission is to support national defense policies by ensuring that the nuclear weapon stockpile meets the highest standards of safety, reliability, security, use control, and military performance. Selected unclassified technical activities and accomplishments are reported here. Topics include advanced manufacturing technologies, intelligent machines, computational simulation, sensors and instrumentation, information management, energy and environment, and weapons technology.

Increasing complexity of experiments coupled with limitations of the previously used computers required improvements in both hardware and software in the Rock Mechanics Laboratories. Increasing numbers of input channels and the need for better graphics could no longer be supplied by DATAVG, an existing software package for data acquisition and display written by D. J. Holcomb in 1983. After researching the market and trying several alternatives, no commercial program was found which met our needs. The previous version of DATAVG had the basic features needed but was tied to obsolete hardware. Memory limitations on the previously used PDP-11 made it impractical to upgrade the software further. With the advances in IBM compatible computers it is now desirable to use them as data recording platforms. With this information in mind, it was decided to write a new version of DATAVG which would take advantage of newer hardware. The new version had to support multiple graphic display windows and increased channel counts. It also had to be easier to use.

A quartz digital accelerometer has been developed which uses double ended tuning forks as the active sensing elements. The authors have demonstrated the ability of this accelerometer to be capable of acceleration measurements between {+-}150G with {+-}0.5G accuracy. They have further refined the original design and assembly processes to produce accelerometers with < 1mG stability in inertial measurement applications. This report covers the development, design, processing, assembly, and testing of these devices.

The thermomechanical effect on the exploratory ramps, drifts, and shafts as a result of high-level nuclear waste disposal is examined using a three-dimensional thermo-elastic model. The repository layout modeled is based on the use of mechanical mining of all excavations with equivalent waste emplacement areal power densities of 57 and 80 kW/acre. Predicted temperatures and stress changes for the north and south access drifts, east main drift, east-west exploratory drift, the north and south Calico Hills access ramps, the Calico Hills north-south exploratory drift, and the optional exploratory studies facility and man and materials shafts are presented for times 10, 35, 50, 100, 300, 500, 1000, 2000, 5000, and 10,000 years after the start of waste emplacement. The study indicates that the east-west exploratory drift at the repository horizon is subject to the highest thermomechanical impact because it is located closest the buried waste canisters. For most exploratory openings, the thermally induced temperatures and stresses tend to reach the maximum magnitudes at approximately 1000 years after waste emplacement.

One of the most widely recognized inadequacies of C is its low-level treatment of arrays. Arrays are not first-class objects in C; an array name in an expression almost always decays into a pointer to the underlying type. This is unfortunate, especially since an increasing number of high-performance computers are optimized for calculations involving arrays of numbers. On such machines, double[] may be regarded as an intrinsic data type comparable to double or int and quite distinct from double. This weakness of C is acknowledged in the ARM, where it is suggested that the inadequacies of the C array can be overcome in C++ by wrapping it in a class that supplies dynamic memory management bounds checking, operator syntax, and other useful features. Such ``smart arrays`` can in fact supply the same functionality as the first-class arrays found in other high-level, general-purpose programming languages. Unfortunately, they are typically expensive in both time and memory and make poor use of advanced floating-point architectures. The reasons for these difficulties are discussed in X3JI6/92-0076//WG21/N0153, ``Optimization of Expressions Involving Array Classes.`` Is there a better solution? The most obvious solution is to make arrays first-class objects and add the functionality mentioned in the previous paragraph. However, this would destroy C compatibility and significantly alter the C++ language. Major conflicts with existing practice would seem inevitable. I propose instead that a numerical array class be adopted as part of the C++ standard library. This class will have the functionality appropriate for the intrinsic arrays found on most high-performance computers, and the compilers written for these computers will be free to implement it as a built-in class. On other platforms, this class may be defined normally, and will provide users with basic array functionality without imposing an excessive burden on the implementor.

Sandia National Laboratories Occupational Medicine Center has primary responsibility for industrial medicine services, applied epidemiology, workers` compensation and sickness absence benefit management, Human Studies Board, employee assistance and health promotion. Each discipline has unique needs for data management, standard and ad hoc reporting and data analysis. The Medical Organization has established a local area network as the preferred computing environment to meet these diverse needs. Numerous applications have been implemented on the LAN supporting some 80 users.

The PANDA code is used to build a multiphase equation of state (EOS) table for iron. Separate EOS tables were first constructed for each of the individual phases. The phase diagram and multiphase EOS were then determined from the Helmholtz free energies. The model includes four solid phases ([alpha],[gamma], [delta], and [var epsilon]) and a fluid phase (including the liquid, vapor, and supercritical regions). The model gives good agreement with experimental thermophysical data, static compression data, phase boundaries, and shock-wave measurements. Contributions from thermal electronic excitation, computed from a quantum-statistical-mechanical model, were found to be very important. This EOS covers a wide range of densities (0--1000 g/cm[sup 3]) and temperatures (0--1.2[times]10[sup 7] K). It is also applicable to RHA steel. The new EOS is used in hydrocode simulations of plate impact experiments, a nylon ball impact on steel, and the shaped charge perforation of an RHA plate. The new EOS table can be accessed through the SNL-SESAME library as material number 2150.

To allow more reliable estimates to be made of the amount of water that permeates through weapon environmental seals, we have generated extensive water permeability coefficient data for numerous o-ring materials, including, weapon-specific formulations of EPDM, butyl, fluorosilicone and silicone. For each material, data were obtained at several temperatures, ranging typically from 21[degrees]C to 80[degrees]C; for selected materials, the effect of relative humidity was monitored. Two different experimental techniques were used for most of the measurements, a permeability cup method and a weight gain/loss approach using, a sensitive microbalance. Good agreement was found between the results from the two methods, adding confidence to the reliability of the measurements. Since neither of the above methods was sufficiently sensitive to measure the water permeability of the butyl material at low temperatures, a third method, based on the use of a commercial instrument which employs a water-sensitive infrared sensor, was applied under these conditions.

ETPRE is a preprocessor for the Event Progression Analysis Code EVNTRE. It reads an input file of event definitions and writes the lengthy EVNTRE code input files. ETPRE's advantage is that it eliminates the error-prone task of manually creating or revising these files since their formats are quite elaborate. The user-friendly format of ETPRE differs from the EVNTRE code format in that questions, branch references, and other event tree components are defined symbolically instead of numerically. When ETPRE is executed, these symbols are converted to their numeric equivalents and written to the output files using format defined in the EVNTRE Reference Manual. Revisions to event tree models are simplified by allowing the user to edit the symbolic format and rerun the preprocessor, since questions, branch references, and other symbols are automatically resequenced to their new values with each execution.

The FALCON Remote Laser Alignment System is used in a high radiation environment to adjust an optical assembly. The purpose of this report is to provide a description of the hardware used and to present the system configuration. Use of the system has increased the reliability and reproducibility of data as well as significantly reducing personnel radiation exposure. Based upon measured radiation dose, radiation exposure was reduced by at least a factor of two after implementing the remote alignment system.

A statistical analysis of test results on 1000 transportation and storage casks revealed the main parameters that determine the properties of DI (ductile iron, a special form of cost iron). These data were used to established a test program in which the mechanical properties (particularly fracture toughness) of 24 DI alloys were determined as a function of their microstructure. Furthermore, the analysis emphasized the effect of test specimen size and different test data evaluation methods. Results of the test program show the prominent effect of pearlite content and graphite nodule structure in the mechanical and fracture toughness characteristics of DI. As the first-order parameter, the pearlite content is responsible for the transition from linear-elastic to elastic-plastic material behavior. The structure of the graphite nodules has a strong effect on the magnitude of the material property values. On the lower shelf, materials with small, homogeneously distributed graphite nodules show higher K{sub IC}-values (matrix-oriented fracture). On the upper shelf, materials with larger graphite nodules show higher fracture toughness (graphite-oriented fracture). With smaller specimens, conservative values were calculated on the upper shelf. This is important for transportation and storage containers of radioactive materials.

The Westinghouse AP600 plant is one of a number of new reactor plant concepts being proposed by industry. One of the unique design features of the AP600 plant is the method by which the containment is cooled during a reactor accident. Through the passive containment cooling system (PCCS), the containment steel shell is passively cooled by natural convection of air and by water film evaporation from the shell exterior surface. In this study an analysis of the AP600 plant was conducted for postulated design basis accident (DBA) and severe accident scenarios using the NRC containment code CONTAIN2 with new code enhancements to model water film transport and evaporation on the exterior of the containment shell.

A 1:6-scale model of a nuclear reactor containment model was built and tested at Sandia National Laboratories as part of research program sponsored by the Nuclear Regulatory Commission to investigate containment overpressure test was terminated due to leakage from a large tear in the steel liner. A limited destructive examination of the liner and anchorage system was conducted to gain information about the failure mechanism and is described. Sections of liner were removed in areas where liner distress was evident or where large strains were indicated by instrumentation during the test. The condition of the liner, anchorage system, and concrete for each of the regions that were investigated are described. The probable cause of the observed posttest condition of the liner is discussed.

This report discusses the testing and evaluation of five commercially available interior video emotion detection (VMD) systems. Three digital VMDs and two analog VMDs were tested. The report focuses on nuisance alarm data and on intrusion detection results. Tests were conducted in a high-bay (warehouse) location and in an office.

An efficient electron-photon Monte Carlo model, taking advantage of approximate periodicity in repetitive satellite structures, is employed to benchmark a more approximate code and to study the shielding effect of a honeycomb-like structure.

This paper represents a review copy for text that is to be included in the Shock and Vibration Recommended Practice Document. This section on pyroshock is written an a general introduction to and description of the topic loading to presentation of an extensive bibliography on the subject. Pyroshock is an evolving science that needs continued focus on both achieving improvements in testing and measurement techniques and advancing instrumentation capabilities. When desired in the near future, recommended practices can be presented. Pyroshock phenomena are associated with separation systems of missiles. spacecraft, and in some cases airplanes. During launch, a rocket driven vehicle may be exposed to 19 to 30 g`s of acceleration with predominant frequencies less than 200 Hz. After launch or takeoffs sections or parts of vehicles may be separated rapidly using explosive driven release mechanisms. Separations can involve stage disconnections for spacecraft sections or payload ejections from missiles and airplanes. At separation, localized pyrotechnic induced accelerations may range from 1000 to over 100,000 g`s at frequencies much higher than 1000 Hz. These pyroshocks are characterized by high intensity, high frequency transients that decay rapidly. Pyroshock impulses have insignificant velocity changes.

A robotic precursor mission to the Lunar surface is proposed. The objective of the mission is to place six to ten 15kg micro-rovers on the planet to investigate equipment left behind during the Apollo missions and to perform other science and exploration duties. The micro-rovers are teleoperated from Earth. An equipment on the rovers is existing technology from NASA, DOE, SDIO, DoD, and industry. The mission is designed to involve several NASA centers, the National Laboratories, multiple universities and the private sector. A major long-term goal which is addressed is the educational outreach aspect of space exploration.

The development of a high mobility platform integrated with high strength manipulation is under development at Sandia National Laboratories. The mobility platform used is a High Mobility Multipurpose Wheeled Vehicle (HMMWV). Manipulation is provided by two Titan 7F Schilling manipulators integrated onboard the HMMWV. The current state of development is described and future plans are discussed.

Controlled impact experiments have been performed on concrete to determine dynamic material properties. The properties assessed include the high-strain-rate yield strength (Hugoniot elastic limit), and details of the inelastic dynamic stress versus strain response of the concrete. The latter features entail the initial void-collapse modulus, the high-stress limiting void-collapse strain, and the stress amplitude dependence of the deformational wave which loads the concrete from the elastic limit to the maximum dynamics stress state. Dynamic stress-versus-strain data are reported over the stress range of the data, from the Hugoniot elastic limit to in excess of 2 GPa. 6 figs, 4 refs, 4 tabs.

Rutherford backscattering spectrometry (RBS), elastic recoil detection (ERD), proton induced x-ray emission (PIXE) and nuclear reaction analysis (NRA) are among the most commonly used, or traditional, ion beam analysis (IBA) techniques. In this review, several adaptations of these IBA techniques are described where either the approach used in the analysis or the application area is clearly non-traditional or unusual. These analyses and/or applications are summarized in this paper.

MOSFETs historically have exhibited large 1/f noise magnitudes because of carrier-defect interactions that cause the number of channel carriers and their mobility to fluctuate. Uncertainty in the type and location of defects that lead to the observed noise have made it difficult to optimize MOSFET processing to reduce the level of 1/f noise. This has limited one`s options when designing devices or circuits (high-precision analog electronics, preamplifiers, etc.) for low-noise applications at frequencies below {approximately}10--100 kHz. We have performed detailed comparisons of the low-frequency 1/f noise of MOSFETs manufactured with radiation-hardened and non-radiation-hardened processing. We find that the same techniques which reduce the amount of MOSFET radiation-induced oxide-trap charge can also proportionally reduce the magnitude of the low-frequency 1/f noise of both unirradiated and irradiated devices. MOSFETs built in radiation-hardened device technologies show noise levels up to a factor of 10 or more lower than standard commercial MOSFETs of comparable dimensions, and our quietest MOSFETs show noise magnitudes that approach the low noise levels of JFETS.

Three dimensional (3D) seismic technology is regarded as one of the most significant improvements in oil exploration technology to come along in recent years. This report provides an assessment of the likely long-term effect on the world oil price and some possible implications for the firms and countries that participate in the oil market. The potential reduction in average finding costs expected from the use of 3D seismic methods and the potential effects these methods may have on the world oil price were estimated. Three dimensional seismic technology is likely to have a more important effect on the stability rather than on the level of oil prices. The competitive position of US oil production will not be affected by 3D seismic technology.

A programming tool has been developed to allow detailed analysis of Fortran programs for massively parallel architectures. The tool obtains counts for various arithmetic, logical, and input/output operations by data types as desired by the user. The tool operates on complete programs and recognizes user-defined and intrinsic language functions as operations that may be counted. The subset of functions recognized by the tool, STOPCNTR, can be extended by altering the input data sets. This feature facilitates analysis of programs targeted for different architectures. The basic usage and operation of the tool is described along with the more important data structures and more interesting algorithmic aspects before identifying future directions in continued development of the tool and discussing STOPCNTR`s inherent advantages and disadvantages.

Tensile properties were measured for nineteen different formulations of epoxy encapsulating materials. Formulations were of different combinations of two neat resins (Epon 828 and Epon 826, with and without CTBN modification), three fillers (ALOX, GNM and mica) and four hardeners (Z, DEA, DETDA-SA and ANH-2). Five of the formulations were tested at -55, -20, 20 and 60C, one formulation at -55, 20 and 71C; and the remaining formulations at 20C. Complete stress-strain curves are presented along with tables of tensile strength, initial modulus and Poisson`s ratio. The stress-strain responses are nonlinear and are temperature dependent. The reported data provide information for comparing the mechanical properties of encapsulants containing the suspected carcinogen Shell Z with the properties of encapsulants containing noncarcinogenic hardeners. Also, calculated shear moduli, based on measured tensile moduli and Poisson`s ratio, are in very good agreement with reported shear moduli from experimental torsional pendulum tests.

Sandia National Laboratories is currently involved in the optimization of a Plane Shock Generator Explosive Lens (PSGEL). This PSGEL component is designed to generate a planar shock wave transmitted to perform a function through a steel bulkhead without rupturing or destroying the integrity of the bulkhead. The PSGEL component consists of a detonator, explosive, brass cone and tamper housing. The purpose of the PSGEL component is to generate a plane shock wave input to 4340 steel bulkhead (wave separator) with a ferro-electric (PZT) ceramic disk attached to the steel on the surface opposite the PSGEL. The planar shock wave depolarizes the PZT 65/35 ferroelectric ceramic to produce an electrical output. Elastic, plastic I and plastic II waves with different velocities are generated in the steel bulkhead. The depolarization of the PZT ceramic is produced by the elastic wave of specific amplitude (10--20 Kilobars) and this process must be completed before (about 0. 15 microseconds) the first plastic wave arrives at the PZT ceramic. Measured particle velocity versus time profiles, using a Velocity Interferometer System for Any Reflector (VISAR) are presented for the brass and steel output free surfaces. Peak pressures are calculated from the particle velocities for the elastic, plastic I and plastic 11 waves in the steel. The work presented here investigates replacing the current 4340 steel with PH 13-8 Mo stainless steel in order to have a more corrosion resistant, weldable and more compatible material for the multi-year life of the component. Therefore, the particle velocity versus time profile data are presented comparing the 4340 steel and PH 13-8 Mo stainless steel. Additionally, in order to reduce the amount of explosive, data are presented to show that LX-13 can replace PBX-9501 explosive to produce more desirable results.

Previous studies in this laboratory have demonstrated that DMBA alters biochemical events associated with lymphocyte activation including formation of the second messenger IP{sub 3} and the release of intracellular Ca{sup 2+}. The purpose of the present studies was to evaluate the mechanisms by which DMBA induces IP{sub 3} formation and Ca{sup 2+} release by examining phosphorylation of membrane associated proteins and activation of protein tyrosine kinases lck and fyn. These studies demonstrated that exposure of HPB-ALL cells to 10{mu}M DMBA resulted in a time- and dose-dependent increase in tyrosine phosphorylation of PLC-{gamma}1 that correlated with our earlier findings of IP{sub 3} formation and Ca{sup 2+} release. These results indicate that the effects of DMBA on the PI-PLC signaling pathway are in part, the result of DMBA-induced tyrosine phosphorylation of the PLC-{gamma}1 enzyme. The mechanism of DMBA- induced tyrosine phosphorylation of PLC-{gamma}1 may be due to activation of fyn or lck kinase activity, since it was found that DMBA increased the activity of these PTKs by more than 2-fold. Therefore, these studies demonstrate that DMBA may disrupt T cell activation by stimulating PTK activation with concomitant tyrosine phosphorylation of PLC-{gamma}1, release of IP{sub 3}, and mobilization of intracellular Ca{sup 2+}.

The Natural Excitation Technique (NExT) is a method of modal testing that allows structures to be tested in their ambient environments. This report is a compilation of developments and results since 1990, and contains a new theoretical derivation of NExT, as well as a verification using analytically generated data. In addition, we compare results from NExT with conventional modal testing for a parked, vertical-axis wind turbine, and, for a rotating turbine, NExT is used to calculate the model parameters as functions of the rotation speed, since substantial damping is derived from the aeroelastic interactions during operation. Finally, we compare experimental results calculated using NExT with analytical predictions of damping using aeroelastic theory.

Characteristics of a long pulse, low-pump rate, atomic xenon (XeI) laser are described. Energy loading up to 170 mJ/cc at pulse widths between 5 and 55 ms is achieved with an electron beam in transverse geometry. The small-signal gain coefficient, loss coefficient, and saturation intensity are inferred from a modified Rigrod analysis. For pump rates between 12 and 42 W/cc the small-signal gain coefficient varies between 0.64 and 0.91%/cm, the loss coefficient varies between 0.027 and 0.088%/cm, and the saturation intensity varies between 61 and 381 W/cm{sup 2}. Laser energy as a function of pulse width and the effects of air and CO{sub 2} impurities are described. The intrinsic laser energy efficiency has a maximum at a pulse width of 10 ms corresponding to a pump rate of 1.6 W/cc. No maximum is observed in the intrinsic power efficiency, A drastic reduction of laser output power is observed for impurity concentrations of greater than {approx}0.01%. An investigation of the dominant laser wavelength in a high Q cavity indicates that the 2.6-{mu}m radiation dominates. A comparison of dominant wavelength with reactor pumped results indicates good agreement when the same cavity optics are used.

This Executive Summary presents the methodology for determining containment requirements for spent-fuel transport casks under normal and hypothetical accident conditions. Three sources of radioactive material are considered: (1) the spent fuel itself, (2) radioactive material, referred to as CRUD, attached to the outside surfaces of fuel rod cladding, and (3) residual contamination adhering to interior surfaces of the cask cavity. The methodologies for determining the concentrations of freely suspended radioactive materials within a spent-fuel transport cask for these sources are discussed in much greater detail in three companion reports: ``A Method for Determining the Spent-Fuel Contribution to Transport Cask Containment Requirements,`` ``Estimate of CRUD Contribution to Shipping Cask Containment Requirements,`` and ``A Methodology for Estimating the Residual Contamination Contribution to the Source Term in a Spent-Fuel Transport Cask.`` Examples of cask containment requirements that combine the individually determined containment requirements for the three sources are provided, and conclusions from the three companion reports to this Executive Summary are presented.

This report discusses recent efforts to characterize the flow and density nonuniformities downstream of heated screens placed in a uniform flow. The Heated Screen Test Facility (HSTF) at Sandia National Laboratories and the Lockheed Palo Alto Flow Channel (LPAFC) were used to perform experiments over wide ranges of upstream velocities and heating rates. Screens of various mesh configurations were examined, including multiple screens sequentially positioned in the flow direction. Diagnostics in these experiments included pressure manometry, hot-wire anemometry, interferometry, Hartmann wavefront slope sensing, and photorefractive schlieren photography. A model was developed to describe the downstream evolution of the flow and density nonuniformities. Equations for the spatial variation of the mean flow quantities and the fluctuation magnitudes were derived by incorporating empirical correlations into the equations of motion. Numerical solutions of these equations are in fair agreement with previous and current experimental results.

Two heliostats representing the state-of-the-art in glass-metal designs for central receiver (and photovoltaic tracking) applications were tested and evaluated at the National Solar Thermal Test Facility in Albuquerque, New Mexico from 1986 to 1992. These heliostats have collection areas of 148 and 200 m{sup 2} and represent low-cost designs for heliostats that employ glass-metal mirrors. The evaluation encompassed the performance and operational characteristics of the heliostats, and examined heliostat beam quality, the effect of elevated winds on beam quality, heliostat drives and controls, mirror module reflectance and durability, and the overall operational and maintenance characteristics of the two heliostats. A comprehensive presentation of the results of these and other tests is presented. The results are prefaced by a review of the development (in the United States) of heliostat technology.

Shipping containers for radioactive materials must be qualified to meet a thermal accident environment specified in regulations, such at Title 10, Code of Federal Regulations, Part 71. Aimed primarily at the shipping container design, this report discusses the thermal testing options available for meeting the regulatory requirements, and states the advantages and disadvantages of each approach. The principal options considered are testing with radiant heat, furnaces, and open pool fires. The report also identifies some of the facilities available and current contacts. Finally, the report makes some recommendations on the appropriate use of these different testing methods.

Within the Yucca Mountain Site Characterization Project, the design of drifts and ramps and evaluation of the impacts of thermomechanical loading of the host rock requires definition of the rock mass mechanical properties. Ramps and exploratory drifts will intersect both welded and nonwelded tuffs with varying abundance of fractures. The rock mass mechanical properties are dependent on the intact rock properties and the fracture joint characteristics. An understanding of the effects of fractures on the mechanical properties of the rock mass begins with a detailed description of the fracture spatial location and abundance, and includes a description of their physical characteristics. This report presents a description of the abundance, orientation, and physical characteristics of fractures and the Rock Quality Designation in the thermomechanical stratigraphic units at the Yucca Mountain site. Data was reviewed from existing sources and used to develop descriptions for each unit. The product of this report is a data set of the best available information on the fracture characteristics.

In this paper we consider the problem of interprocessor communication on a Completely Connected Optical Communication Parallel Computer (OCPC). The particular problem we study is that of realizing an h-relation. In this problem, each processor has at most h messages to send and at most h messages to receive. It is clear that any 1-relation can be realized in one communication step on an OCPC. However, the best known p-processor OCPC algorithm for realizing an arbitrary h-relation for h > 1 requires {Theta}(h + log p) expected communication steps. (This algorithm is due to Valiant and is based on earlier work of Anderson and Miller.) Valiant`s algorithm is optimal only for h = {Omega}(log p) and it is an open question of Gereb-Graus and Tsantilas whether there is a faster algorithm for h = o(log p). In this paper we answer this question in the affirmative by presenting a {Theta} (h + log log p) communication step algorithm that realizes an arbitrary h-relation on a p-processor OCPC. We show that if h {le} log p then the failure probability can be made as small as p{sup -{alpha}} for any positive constant {alpha}.

This report discusses the relationship between the New and Malloc operators used in programming C++.

The numerical stability and truncation error of a family of differencing schemes for viscoplastic constitutive relations in wavecodes is investigated. A von Neumann stability analysis is performed for a one-dimensional model problem. This analysis identifies two differencing methods that have no restriction on the time step size beyond the usual Courant-Friedrichs-Lewy condition. One of these methods is first-order accurate, and the other is second-order accurate. Implementation of one of these methods in the three-dimensional wavecode CTH is discussed. © 1993 Academic Press. All rights reserved.

Strained-layer semiconductors have revolutionized modern heterostructure devices by exploiting the modification of semiconductor band structure associated with the coherent strain of lattice-mismatched heteroepitaxy. The modified band structure improves transport of holes in heterostructures and enhances the operation of semiconductor lasers. Strained-layer epitaxy also can create materials whose band gaps match wavelengths (e.g. 1.06 μm and 1.32 μm) not attainable in ternary epitaxial systems lattice matched to binary substrates. Other benefits arise from metallurgical effects of modulated strain fields on dislocations. Lattice mismatched epitaxial layers that exceed the limits of equilibrium thermodynamics will degrade under sufficient thermal processing by converting the as-grown coherent epitaxy into a network of strain-relieving dislocations. After presenting the effects of strain on band structure, we describe the stability criterion for rapid-thermal processing of strained-layer structures and the effects of exceeding the thermodynamic limits. Finally, device results are reviewed for structures that benefit from high temperature processing of strained-layer superlattices.

When an object is subjected to the flow of combustion gas at a different temperature, the thermal responses of the object and the surrounding gas become coupled. The ability to model this interaction is of primary interest in the design of components which must withstand fire environments. One approach has been to decouple the problem and treat the incident flux on the surface of the object as being emitted from a blackbody at an approximate gas temperature. By neglecting the presence of the participating media, this technique overpredicts the heat fluxes initially acting on the object surface. The main goal of this work is to quantify the differences inherent in treating the combustion media as a blackbody as opposed to a gray gas. This objective is accomplished by solving the coupled participating media radiation and conduction heat transfer problem. A transient conduction analysis of a vertical flat plate was performed using a gray gas model to provide a radiation boundary condition. A 1-D finite difference algorithm was used to solve the conduction problem at locations along the plate. The results are presented in terms of nondimensional parameters and include both average and local heat fluxes as a function of time. Early in the transient, a reduction in net heat fluxes of up to 65% was observed for the gray gas results as compared to the blackbody cases. This reduction in the initial net heat flux results in lower surface temperatures for the gray gas case. Due to the initially reduced surface temperatures, the gray gas net heat flux exceeds the net blackbody heat flux with increasing time. For radiation Biot numbers greater than 5, or values of the radiation parameter less than 10-2, the differences inherent in treating the media as a gray gas are negligible and the blackbody assumption is valid. Overall, the results clearly indicate the importance of participating media treatment in the modeling of the thermal response of objects in fires and large combustion systems.

This paper gives an estimate of the cost to produce electricity from hot-dry rock (HDR). Employment of the energy in HDR for the production of electricity requires drilling multiple wells from the surface to the hot rock, connecting the wells through hydraulic fracturing, and then circulating water through the fracture system to extract heat from the rock. The basic HDR system modeled in this paper consists of an injection well, two production wells, the fracture system (or HDR reservoir), and a binary power plant. Water is pumped into the reservoir through the injection well where it is heated and then recovered through the production wells. Upon recovery, the hot water is pumped through a heat exchanger transferring heat to the binary, or working, fluid in the power plant. The power plant is a net 5.1-MW[sub e] binary plant employing dry cooling. Make-up water is supplied by a local well. In this paper, the cost of producing electricity with the basic system is estimated as the sum of the costs of the individual parts. The effects on cost of variations to certain assumptions, as well as the sensitivity of costs to different aspects of the basic system, are also investigated.

We report our progress on the physical optics modelling of Sandia/AT&T SXPL experiments. The code is benchmarked and the 10X Schwarzchild system is being studied.

For a number of communications and other applications, switched filter banks (some channelizers) and switched delay lines (phase shifters) are extremely useful. Since YBaCuO and TICaBaCuO filters and delay lines have shown significant performance enhancements over their conventional counterparts, a purely superconducting version of the switched assemblies could result in additional improvements. A thermal switch has been developed that provides good isolation and insertion loss with adequate switching times to allow a monolithic approach to the switched lines and filter banks. Filter banks in the 8-11 GHz range have been demonstrated with insertion losses < 1 dB and out-of-band rejection greater than a package-limited 50 dB. Switched delay lines have been fabricated with insertion losses less than 0.3 dB/bit and peak phase deviations from linearity of less than 5 degrees over 30 GHz bandwidths. © 1993 IEEE

Parallel computers are becoming more powerful and more complex in response to the demand for computing power by scientists and engineers. Inevitably, new and more complex I/O systems will be developed for these systems. In particular we believe that the I/O system must provide the programmer with the ability to explicitly manage storage (despite the trend toward complex parallel file systems and caching schemes). One method of doing so is to have a partitioned secondary storage in which each processor owns a logical disk. Along with operating system enhancements which allow overheads such as buffer copying to be avoided and libraries to support optimal remapping of data, this sort of I/O system meets the needs of high performance computing.

The design-basis, defense-related, transuranic waste to be emplaced in the Waste Isolation Pilot Plant may, if sufficient H2O, nutrients, and viable microorganisms are present, generate significant quantities of gas in the repository after filling and sealing. We summarize recent results of laboratory studies of anoxic corrosion and microbial activity, the most potentially significant processes. We also discuss possible implications for the repository gas budget.

A series of experiments has been performed to evaluate the effectiveness of a Whipple bumper shield to orbital space debris at impact velocities of ∼ 10 km/s. Upon impact by a 19 mm (0.87 mm thick, L/D ∼0.5) flier plate, the thin aluminum bumper shield disintegrates into a debris cloud. The debris cloud front propagates axially at velocities of ∼14 km/s and expands radially at a velocity of ∼7 km/s. Subsequent loading by the debris on a 3.2 mm thick aluminum substructure placed 114 mm from the bumper penetrates the substructure completely. However, when the diameter of the flier plate is reduced to 12.7 mm, the substructure, although damaged is not perforated. Numerical simulations performed using the multi-dimensional hydrodynamics code CTH also predict complete perforation of the substructure by the subsequent debris cloud for the larger flier plate. The numerical simulation for a 12.7 mm flier plate, however, shows a strong dependence on assumed impact geometry, i. e., a spherical projectile impact geometry does not result in perforation of the substructure by the debris cloud, while the flat plate impact geometry results in perforation. © 1993.

Sub-optimal design practices can reduce the radiation hardness of a circuit even though it is fabricated in a radiation hardened process. This is especially true for a nonvolatile memory, as compared to a standard digital circuit, where high voltages and unusual bias conditions are required. This paper will discuss the design techniques used in the development of a 64K EEPROM (Electrically Erasable Programmable Read Only Memory) to maximize radiation hardness. The circuit radiation test results will be reviewed in order to provide validation of the techniques. © 1993 IEEE

The U.S. Department of Energy (DOE) is developing the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico as a facility for the long-term disposal of defense-related transuranic (TRU) wastes. Use of the WIPP for waste disposal is contingent on demonstrations of compliance with applicable regulations of the U.S. Environmental Protection Agency (EPA). This paper addresses issues related to modeling gas and brine migration at the WIPP for compliance with both EPA 40 CFR 191 (the Standard) and 40 CFR 268.6 (the RCRA). At the request of the WIPP Project Integration Office (WPIO) of the DOE, the WIPP Performance Assessment (PA) Department of Sandia National Laboratories (SNL) has completed preliminary uncertainty and sensitivity analyses of gas and brine migration away from the undisturbed repository. This paper contains descriptions of the numerical model and simulations, including model geometries and parameter values, and a summary of major conclusions from sensitivity analyses. Because significant transport of contaminants can only occur in a fluid (gas or brine) medium, two-phase flow modeling can provide an estimate of the distance to which contaminants can migrate. Migration of gas or brine beyond the RCRA 'disposal-unit boundary' or the Standard's accessible environment constitutes a potential, but not certain, violation and may require additional evaluations of contaminant concentrations.

This paper presents an infinite impulse response (IIR) filtering technique for reducing structural vibration in remotely operated robotic systems. The technique uses a discrete filter between the operator's joy stick and the robot controller to alter the inputs of the system so that residual vibration and swing are reduced. A linearized plant model of the system is analyzed in the discrete time domain, and the filter is designed using pole-zero placement in the z-plane. This technique has been successfully applied to a two link flexible arm and a gantry crane with a suspended payload.

Before disposing of transuranic radioactive waste at the Waste Isolation Pilot Plant (WIPP), the United States Department of Energy (DOE) must evaluate compliance with long-term regulations of the United States Environmental Protection Agency (EPA). Sandia National Laboratories (SNL) is conducting iterative performance assessments (PAs) of the WIPP for the DOE to provide interim guidance while preparing for final compliance evaluations. This paper describes the 1992 preliminary comparison with Subpart B of the Environmental Standards for the Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes (40 CFR 191), which regulates long-term releases of radioactive waste. Results of the 1992 PA are preliminary, and cannot be used to determine compliance or noncompliance with EPA regulations because portions of the modeling system and data base are incomplete. Results are consistent, however, with those of previous iterations of PA, and the SNL WIPP PA Department has high confidence that compliance with 40 CFR 191B can be demonstrated. Comparison of predicted radiation doses from the disposal system also gives high confidence that the disposal system is safe for long-term isolation.

Before disposing of transuranic radioactive waste at the Waste Isolation Pilot Plant (WIPP), the United States Department of Energy (DOE) must evaluate compliance with long-term regulations of the United States Environmental Protection Agency (EPA), specifically the Environmental Standards for the Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes (40 CFR 191), and the Land Disposal Restrictions (40 CFR 268) of the Hazardous and Solid Waste Amendments to the Resource Conservation and Recovery Act (RCRA). Sandia National Laboratories (SNL) is conducting iterative performance assessments (PAs) of the WIPP for the DOE to provide interim guidance while preparing for final compliance evaluations. This paper provides background information on the regulations, describes the SNL WIPP PA Department's approach to developing a defensible technical basis for consistent compliance evaluations, and summarizes the major observations and conclusions drawn from the 1991 and 1992 PAs.

Two space applications are considered for (electrically) contactless coilguns: launch of small satellites into low-earth orbit, and launch of lunar liquid oxygen (LLOX) from the moon to the stationary Lagrangian point L2. For the earth-to-orbit (ETO) application, the baseline conceptual design consists of a 960-m long gun sited in a tunnel at 25° inclination. The gun launches an 1820-kg package that includes a 100-kg satellite and a 650-kg boost rocket for orbital insertion. For the lunar application, the launcher is 200 m long. A 100-kg load of LLOX is packaged in a 10-kg fiber-wrapped tank, accelerated at 2 kgees in an aluminum bucket (armature), and launched at 2.33 km/s at 30-minute intervals. The canisters arrive at L2 2.97 days later and are captured by robotic tugs that deliver them to a fuel depot. The total mass of LLOX delivered per year is 867 Mg (metric tons). © 1993 IEEE

We postulate that there is a required velocity of magnetic flux into a plasma-armature railgun to keep the armature from expanding toward the breech and thereby changing the nature of the forward-going force. Testing this idea with data from several guns we find confirmation, provided the required flux velocity increases with the square of the linear current density. This leads to the conclusion that these guns have a momentum limit while they are operating as true electromagnetic launchers. That limit is derived. High-performance railguns reach this limit during current rise, and most of their momentum comes from a hybrid phase. The hybrid phase has a pressure limitation at high velocity similar to electrothermal, light-gas, and powder guns. The 6 km/s “velocity limit” is explained by this pressure limitation. © 1993 IEEE

Different hardness-assurance tests are often required for advanced bipolar devices than for CMOS devices. In this work, the dose-rate dependence of bipolar current-gain degradation is mapped over a wide range of dose rates for the first time, and it is very different from analogous MOSFET curves. Annealing experiments following irradiation show negligible change in base current at room temperature, but significant recovery at temperatures of 100°C and above. In contrast to what is observed in MOSFET’s, irradiation and annealing tests cannot be used to predict the low-dose-rate response of bipolar devices. A comparison of x-ray-induced and 60Co gamma-ray-induced gain degradation is reported for the first time for bipolar transistors. The role of the emitter bias during irradiation is also examined. Implications for hardening and hardness assurance are discussed. © 1993 IEEE

Vadose-zone moisture transport near an impermeable barrier has been under study at a field site near Albuquerque, NM since 1990. Moisture content and temperature have been monitored in the subsurface on a regular basis; both undergo a seasonal variation about average values. Even though the slab introduces two-dimensional effects on the scale of the slab, moisture and heat transport is predominantly vertical. Numerical simulations, based on the models developed by Philip and de Vries (1957) and de Vries (1958), indicate that the heat flow is conduction-dominated while the moisture movement is dominated by diffusive vapor distillation. Model predictions of the magnitude and extent of changes in moisture content underneath the slab are in reasonable agreement with observation.

A Sandia National Laboratories/AT&T Bell Laboratories Team is developing a soft x-ray projection lithography tool that uses a compact laser plasma as a source of 14 nm x-rays. Optimization of the 14 nm x-rays source brightness is a key issue in this research. This paper describes our understanding of the source as it has been obtained through the use of computer simulations utilizing the LASNEX radiation-hydrodynamics code.

Ion-beam-induced charge-collection imaging (IBICC) has been used to study the SEU mechanisms of the Sandia TA670 16K-bit SRAM. Quantitative charge-collection spectra from known regions of the memory cell have been derived with this technique. For 2.4-MeV He ions at normal incidence, charge collection depth for a reverse-biased p+ drain strike is estimated to be 4.8±0.4 μm. Heavy-ion strikes to the reverse-biased p-well result in nearly complete collection of deposited charge to a depth of 5.5±0.5 μm. A charge amplification effect in the n-on drain is identified and is due to either bipolar amplification or a shunt effect in the parasitic vertical npn bipolar transistor associated with the n+/n substrate, p-well, and n+ drain. This effect is present only when the n+ drain is at 0V bias. When coupled with previous SEU-imaging, these results strongly suggest that the dominant SEU mechanism in this SRAM is a heavy-ion strike to the n-on transistor drain. © 1993 IEEE

The Vapnik-Chervonenkis (V-C) dimension is an important combinatorial tool in the analysis of learning problems in the PAC framework. For polynomial learnability, we seek upper bounds on the V-C dimension that are polynomial in the syntactic complexity of concepts. Such upper bounds are automatic for discrete concept classes, but hitherto little has been known about what general conditions guarantee polynomial bounds on V-C dimension for classes in which concepts and examples are represented by tuples of real numbers. In this paper, we show that for two general kinds of concept class the V-C dimension is polynomially bounded as a function of the syntactic complexity of concepts. One is classes where the criterion for membership of an instance in a concept can be expressed as a formula (in the first-order theory of the reals) with fixed quantification depth and exponentially-bounded length, whose atomic predicates are polynomial inequalities of exponentially-bounded degree. The other is classes where containment of an instance in a concept is testable in polynomial time, assuming we may compute standard arithmetic operations on reals exactly in constant time. Our results show that in the continuous case, as in the discrete, the real barrier to efficient learning in the Occam sense is complexity-theoretic and not information-theoretic. We present examples to show how these results apply to concept classes defined by geometrical figures and neural nets, and derive polynomial bounds on the V-C dimension for these classes.

During hydrocarbon reservoir stimulations, such as hydraulic fracturing, the cracking and slippage of the formation results in the emission of seismic energy. The objective of this study was to determine the properties of these induced micro-seisms. A hydraulic fracture experiment was performed in the Piceance Basin of Western Colorado to induce and record micro-seismic events. The formation was subjected to four processes; breakdown/ballout, step-rate test, KCL mini-fracture, and linear-gel mini-fracture. Micro-seisms were acquired with an advanced three-component wall-locked seismic accelerometer package, placed in an observation well 211 ft offset from the fracture well. During the two hours of formation treatment, more than 1200 micro-seisms with signal-to-noise ratios in excess of 20 dB were observed. The observed micro- seisms had a nominally flat frequency spectrum from 100 Hz to 1500 Hz and lack the spurious tool-resonance effects evident in previous attempts to measure micro-seisms. Both p-wave and s-wave arrivals are clearly evident in the data set, and hodogram analysis yielded coherent estimates of the event locations. This paper describes the characteristics of the observed micro- seismic events (event occurrence, signal-to-noise ratios, and bandwidth) and illustrates that the new acquisition approach results in enhanced detectability and event location resolution.

Many designs use EPLDs (Erasable Programmable Logic Devices) to implement control logic and state machines. If the design is slow, timing through the EPLD is not crucial so designers often treat the device as a black box. In high speed designs, timing through the EPLD is critical. In these cases a thorough understanding of the device architecture is necessary. Lessons learned in the implementation of a high-speed design using the Altera EPM5130 are discussed.

A new Assembly Test Chip, ATC04, designed to measure mechanical stresses at the die surface has been built and tested. This CMOS chip 0.25 in. on a side, has an array of 25 piezoresistive stress sensing cells, four resistive heaters and two ring oscillators. The ATCO4 chip facilitates making stress measurements with relatively simple test equipment and data analysis. The design, use, and accuracy of the chip are discussed and initial results are presented from three types of stress measurement experiments: four-point bending calibration, single point bending of a substrate with an ATC04 attached by epoxy, and stress produced by a liquid epoxy encapsulant.

The feasibility of utilizing a groundbased laser without an orbital mirror for space debris removal is examined. Technical issues include atmospheric transmission losses, adaptive-optics corrections of wavefront distortions, laser field-of-view limitations, and laser-induced impulse generation. The physical constraints require a laser with megawatt output, long run-time capability, and wavelength with good atmospheric transmission characteristics. It is found that a 5-MW reactor-pumped laser can deorbit debris having masses of the order of one kilogram from orbital altitudes to be used by Space Station Freedom. Debris under one kilogram can be deorbited after one pass over the laser site, while larger debris can be deorbited or transferred to alternate orbits after multiple passes over the site.

Flux-flow based devices such as the superconducting flux flow transistor and magnetically controlled long junctions have been made from thin films of TICaBaCuO and YBaCuO. The devices are based on the magnetic control of flux flow in their respective structures: a long junction or an array of weak links. The equivalent circuits of the two devices are similar: a low impedance input control line, an output impedance of 3-20 Q and an active current-controlled element. The long junctions have tended to be slower, have lower gain and be somewhat less noisy than their counterparts. The performance of circuits such as narrowband and distributed amplifiers (SO GHz bandwidths, noise figures < 3 dB), phase shifters (continuous with < 2 dB loss 4-40 GHz), logic gates (2-3 ps gate delays) and memories made using these devices will be compared and analyzed. © 1993 IEEE

Automatic motion planning of a spray cleaning robot with collision avoidance is presented in this paper. In manufacturing environments, electronic and mechanical components are traditionally cleaned by spraying or dipping them using chlorofluorocarbon (CFC) solvents. As new scientific data show that such solvents are major causes for stratospheric ozone depletion, an alternate cleaning method is needed. Part cleaning with aqueous solvents is environmentally safe, but can require precision spraying at high pressures for extended time periods. Operator fatigue during manual spraying can decrease the quality of the cleaning process. By spraying with a robotic manipulator, the necessary spray accuracy and consistency to manufacture high-reliability components can be obtained. Our motion planner was developed to automatically generate motions for spraying robots based on the part geometry and cleaning process parameters. For spraying paint and other coatings a geometric description of the parts and robot may be sufficient for motion planning, since coatings are usually done over the visible surfaces. For spray cleaning, the requirement to reach hidden surfaces necessitates the addition of a rule-based method to the geometric motion planning.

The geochemical properties of a porous sand and several tracers (Ni, Br, and Li) have been characterized for use in a caisson experiment designed to validate sorption models used in models of reactive transport. The surfaces of the sand grains have been examined by a combination of techniques including potentiometric titration, acid leaching, optical microscopy, and scanning electron microscopy with energy-dispersive spectroscopy. The surface studies indicate the presence of small amounts of carbonate, kaolinite and iron-oxyhydroxides. Adsorption of nickel, lithium and bromide by the sand was measured using batch techniques. Bromide was not sorbed by the sand. A linear (Kd) or an isotherm sorption model may adequately describe transport of Li; however, a model describing the changes of pH and the concentrations of other solution species as a function of time and position within the caisson and the concomitant effects on Ni sorption may be required for accurate predictions of nickel transport.

For problems where media properties are measured at one scale and applied at another, scaling laws or models must be used in order to define effective properties at the scale of interest. The accuracy of such models will play a critical role in predicting flow and transport through the Yucca Mountain Test Site given the sensitivity of these calculations to the input property fields. Therefore, a research program has been established to gain a fundamental understanding of how properties scale with the aim of developing and testing models that describe scaling behavior in a quantitative manner. Scaling of constitutive rock properties is investigated through physical experimentation involving the collection of suites of gas permeability data measured over a range of discrete scales. Also, various physical characteristics of property heterogeneity and the means by which the heterogeneity is measured and described and systematically investigated to evaluate their influence on scaling behavior. This paper summarizes the approach that is being taken toward this goal and presents the results of a scoping study that was conducted to evaluate the feasibility of the proposed research.

Experimental results exploring gravity-driven wetting front instability in a pre-wetted, rough-walled analog fracture are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport.

In an attempt to achieve completeness and consistency, the performance-assessment analyses developed by the Yucca Mountain Project are tied to scenarios described in event trees. Development of scenarios requires describing the constituent features, events, and processes in detail. Several features and processes occurring at the waste packages and the rock immediately surrounding the packages (i.e., the near field) have been identified: the effects of radiation on fluids in the near-field rock, the path-dependency of rock-water interactions, and the partitioning of contaminant transport between colloids and solutes. This paper discusses some questions regarding these processes that the near-field performance-assessment modelers will need to have answered to specify those portions of scenarios dealing with the near field.

Experiments investigating the behavior of individual, gravity-driven fingers in an initially dry, rough-walled analog fracture are presented. Fingers were initiated from constant flow to a point source. Finger structure is described in detail; specific phenomena observed include: desaturation behind the finger-tip, variation in finger path, intermittent flow structures, finger-tip bifurcation, and formation of dendritic sub-fingers. Measurements were made of finger-tip velocity, finger width, and finger-tip length. Non-dimensional forms of the measured variables are analyzed relative to the independent parameters, flow rate and gravitational gradient.

The potential repository system is intended to isolate high-level radioactive waste at Yucca Mountain according to the performance objective - 10 CFR 60.112. One subsystem that may contribute to achieving this objective is the sealing subsystem. This subsystem is comprised of sealing components in the shafts, ramps, underground network of drifts, and the exploratory boreholes. Sealing components can be rigid, as in the case of a shaft seal, or can be more compressible, as in the case of drift fill comprised of mined rockfill. This paper presents the preliminary seismic response of discrete sealing components in welded and nonwelded tuff. Special consideration is given to evaluating the stress in the seal, and the behavior of the interface between the seal and the rock. The seismic responses are computed using both static and dynamic analyses. Also presented is an evaluation of the maximum seismic response encountered by a drift seal with respect to the angle of incidence of the seismic wave. Mitigation strategies and seismic design considerations are proposed which can potentially enhance the overall response of the sealing component and subsequently, the performance of the overall repository system.

This analytical study examines the effect of initial thermodynamic conditions on the loads generated by the combustion of homogeneous hydrogen-air-steam mixtures. The effect of initial temperature, pressure, hydrogen concentration, and steam concentration is evaluated for two cases, (1) constant volume and (2) constant initial pressure. For each case, the Adiabatic, Isochoric, Complete Combustion (AICC), Chapman-Jouguet (CJ), and normally reflected CJ pressures are calculated for a range of hydrogen and steam concentrations representative of the entire flammable regime. For detonation loads, pressure profiles and time-histories are also evaluated in one-dimensional Cartesian geometry. The results show that to a first approximation, the AICC and CJ pressures are directly proportional to the initial density. Increasing the hydrogen concentration up to stoichiometric concentrations significantly increases the AICC, CJ, and reflected CJ pressures. For the constant volume case, the AICC, CJ, and reflected CJ pressures increase with increasing hydrogen concentration on the rich side of stoichiometric concentrations. For the constant initial pressure case, the AICC, CJ, and reflected CJ pressures decrease with increasing hydrogen concentration on the rich side of stoichiometric values. The addition of steam decreases the AICC, CJ, and reflected CJ pressures for the constant initial pressure case, but increases them for the constant volume case. For detonations, the pressure time-histories can be normalized with the AICC pressure and the reverberation time for Cartesian geometry. © 1993.

We present a new methodology for predicting the fatigue life of solder joints for electronics applications. This approach involves the integration of experimental and computational techniques. The first stage involves correlating the manufacturing and processing parameters with the starting microstructure of the solder joint. The second stage involves a series of experiments that characterize the evolution of the microstructure during thermal cycling. The third stage consists of a computer modeling and simulation effort that utilizes the starting microstructure and experimental data to produce a reliability prediction of the solder joint. This approach is an improvement over current methodologies because it incorporates the microstructure and properties of the solder directly into the model and allows these properties to evolve as the microstructure changes during fatigue.

The results of experiments on the energy losses in switches are presented. All experiments were circuit code modeled after the development of a new switch loss version based on Braginskii's spark channel theory for gasses. The circuit code predicts switch energy loss and peak currents as a function of time. Slight constant offsets between the theory and data that depended on the switching dielectric were observed. Plasma conductivity for each tested dielectric was modified to lessen this offset. An excellent agreement between the theory and experiment was also observed. The new model successfully predicted the series resistance of Marx generators.

Yucca Mountain, Nevada is a potential site for a high-level radioactive-waste repository. Uncertainty and sensitivity analyses were performed to estimate critical factors in the performance of the site with respect to a criterion in terms of pre-waste-emplacement ground-water travel time. The degree of failure in the analytical model to meet the criterion is sensitive to the estimate of fracture porosity in the upper welded unit of the problem domain. Fracture porosity is derived from a number of more fundamental measurements including fracture frequency, fracture orientation, and the moisture-retention characteristic inferred for the fracture domain.

This report contains an outline of the Solar Thermal Design Assistance Center's (STDAC) major activities and accomplishments in Fiscal Year 1992 (FY92). The report describes the resources allocated to fund STDAC and the personnel needed to carry out STDAC activities and accomplishments. It also contains a comprehensive list of persons that called STDAC for consultation in FY92.

Images taken with a synthetic aperture radar (SAR) on an airplane were distorted with phase errors generated by a computer program that simulates the propagation of radar waves through the disturbed ionosphere. The simulation is for an orbiting SAR imaging a scene on the ground. Both the spatially-invariant (decorrelation length projected onto the ground much larger than the scene size) and spatially-variant (decorrelation length much smaller than the scene size) cases are described. The spatially-invariant phase errors can be removed using several different algorithms. Problems and strategies in restoring SAR images distorted with spatially-variant phase errors are discussed.

Future challenges facing the nonproliferation community will undoubtedly change the normal way of doing business'' in international safeguards. New technology will emerge in support of compliance concepts such as transparency and openness, regional security assurance, bilateral cooperation, and special. or non-routine inspections. Technologies address in remote unattended monitoring, integrated on-site monitoring, environmental monitoring, satellite and aerial over-flight systems, equipment for special inspectios, and sharable data information fusion and management, are just a few examples of potential technologics for new nonproliferation monitoring regimes.

We describe an algorithm for the static load balancing of scientific computations that generalizes and improves upon spectral bisection. Through a novel use of multiple eigenvectors, our new spectral algorithm can divide a computation into 4 or 8 pieces at once. This leads to balanced partitions that have lower communication overhead and are less expensive to compute than those of spectral bisection. In addition, our approach automatically works to minimize message contention on a hypercube or mesh architecture.

This paper describes a collaborative effort between Sandia National Laboratories and the Rocketdyne Division of Rockwell International Corporation to develop an automated braze paste dispensing system for rocket engine nozzle manufacturing. The motivation for automating this manufacturing process is to reduce the amount of labor and excess material required. A critical requirement for this system is the automatic location of key nozzle features using non-contact sensors. Sandia has demonstrated that the low-cost Multi-Axis Seam Tracking (MAST) capacitive sensor can be used to accurately locate the nozzle surface and tube gaps.

This paper examines some of the metrics that are commonly used to design correlation filter's for optical pattern recognition, including: the Fisher ratio, the signal-to-noise ratio, the equal correlation peak (ECP) constraint, and normalized correlation. Attention is given to the underlying assumptions that are required to move from Bayesian decision theory to a particular metric or design principle. Since a Bayes classifier is statistically optimum, this provides a means for assessing the merit of a particular approach. Although the authors only examine a few metrics in this paper, the approach is general and should be useful for assessing the merit and applicability of any of the numerous filter designs that have been proposed in the optical pattern recognition community.

This report discusses electronic isolators which are used to maintain electrical separation between safety and non-safety systems in nuclear power plants. The concern is that these devices may fail allowing unwanted signals or energy to act upon safety systems, or preventing desired signals from performing their intended function. While operational history shows many isolation device problems requiring adjustments and maintenance, we could not find incidents where there was a safety implication. Even hypothesizing multiple simultaneous failures did not lead to significant contributions to core damage frequency. Although the analyses performed in this study were not extensive or detailed, there seems to be no evidence to suspect that isolation device failure is an issue which should be studied further.

This report documents the fiscal year 1992 activities of the, Utility Battery Storage Systems Program (UBS) of the US Department of Energy (DOE), Office of Energy Management (OEM). The UBS program is conducted by Sandia National Laboratories (SNL). UBS is responsible for the engineering development of integrated battery systems for use in utility-energy-storage (UES) and other stationary applications. Development is accomplished primarily through cost-shared contracts with industrial organizations. An important part of the development process is the identification, analysis, and characterization of attractive UES applications. UBS is organized into five projects: Utility Battery Systems Analyses; Battery Systems Engineering; Zinc/Bromine; Sodium/Sulfur; Supplemental Evaluations and Field Tests. The results of the Utility Systems Analyses are used to identify several utility-based applications for which battery storage can effectively solve existing problems. The results will also specify the engineering requirements for widespread applications and motivate and define needed field evaluations of full-size battery systems.

The sixth experiment of the Integral Effects Test (IET-6) series was conducted to investigate the effects of high pressure melt ejection on direct containment heating. Scale models of the Zion reactor pressure vessel (RPV), cavity, instrument tunnel, and subcompartment structures were constructed in the Surtsey Test Facility at Sandia National Laboratories. The RPV was modeled with a melt generator that consisted of a steel pressure barrier, a cast MgO crucible, and a thin steel inner liner. The melt generator/crucible had a hemispherical bottom head containing a graphite limitor plate with a 4-cm exit hole to simulate the ablated hole in the RPV bottom head that would be formed by ejection of an instrument guide tube in a severe nuclear power plant accident. The cavity contained 3.48 kg of water, which corresponds to condensate levels in the Zion plant, and the containment basement floor was dry. A 43-kg initial charge of iron oxide/aluminum/chromium thermite was used to simulate corium debris on the bottom head of the RPV. Molten thermite was ejected by steam at an initial pressure of 6.3 MPa into the reactor cavity. The Surtsey vessel atmosphere contained pre-existing hydrogen to represent partial oxidation of the zirconium in the Zion core. The initial composition of the vessel atmosphere was 87.1 mol.% N[sub 2], 9.79 mol.% O[sub 2], and 2.59 mol.% H[sub 2], and the initial absolute pressure was 198 kPa. A partial hydrogen burn occurred in the Surtsey vessel. The peak vessel pressure increase was 279 kPa in IET-6, compared to 246 kPa in the IET-3 test. The total debris mass ejected into the Surtsey vessel in IET-6 was 42.5 kg. The gas grab sample analysis indicated that there were 180 g[center dot] moles of pre-existing hydrogen, and that 308[center dot]moles of hydrogen were produced by steam/metal reactions. About 335 g[center dot]moles of hydrogen burned, and 153 g[center dot]moles remained unreacted.

The Sandia National Laboratories (SNL) Engineering Analysis Code Access System (SEACAS) is a collection of structural and thermal codes and utilities used by analysts at SNL. The system includes pre- and post-processing codes, analysis codes, database translation codes, support libraries, UNIX{trademark} shell scripts, and an installation system. SEACAS is used at SNL on a daily basis as a production, research, and development system for the engineering analysts and code developers. Over the past year, approximately 180 days of Cray Y-MP{trademark} CPU time have been used at SNL by SEACAS codes. The job mix includes jobs using only a few seconds of CPU time, up to jobs using two and one-half days of CPU time. SEACAS is running on several different systems at SNL including Cray Unicos, Hewlett Packard HP-UX{trademark}, Digital Equipment Ultrix{trademark}, and Sun SunOS{trademark}. This document is a short description of the codes the SEACAS system.

This bulletin from Sandia Laboratories presents current research on testing technology. Fiber optics systems at the Nevada Test Site is replacing coaxial cables. The hypervelocity launcher is being used to test orbital debris impacts with space station shielding. A digital recorder makes testing of high-speed water entries possible. Automobile engine design is aided by an instrumented head gasket that detects the combustion zone. And composite-to-metal strength and fatigue tests provide new data on joint failures in wind turbine joint tests.

The CONTAIN computer code is a best-estimate, integrated analysis tool for predicting the physical, chemical, and radiological conditions inside a nuclear reactor containment building following the release of core material from the primary system. CONTAIN is supported primarily by the U. S. Nuclear Regulatory Commission (USNRC), and the official code versions produced with this support are intended primarily for the analysis of light water reactors (LWR). The present manual describes CONTAIN LMR/1B-Mod. 1, a code version designed for the analysis of reactors with liquid metal coolant. It is a variant of the official CONTAIN 1.11 LWR code version. Some of the features of CONTAIN-LMR for treating the behavior of liquid metal coolant are in fact present in the LWR code versions but are discussed here rather than in the User`s Manual for the LWR versions. These features include models for sodium pool and spray fires. In addition to these models, new or substantially improved models have been installed in CONTAIN-LMR. The latter include models for treating two condensables (sodium and water) simultaneously, sodium atmosphere and pool chemistry, sodium condensation on aerosols, heat transfer from core-debris beds and to sodium pools, and sodium-concrete interactions. A detailed description of each of the above models is given, along with the code input requirements.

Inelastic material constitutive relations for elastoplasticity coupled with continuum damage mechanics are investigated. For elastoplasticity, continuum damage mechanics, and the coupled formulations, rigorous thermodynamic frameworks are derived. The elastoplasticity framework is shown to be sufficiently general to encompass J{sub 2} plasticity theories including general isotropic and kinematic hardening relations. The concepts of an intermediate undamaged configuration and a fictitious deformation gradient are used to develop a damage representation theory. An empirically-based, damage evolution theory is proposed to overcome some observed deficiencies. Damage deactivation, which is the negation of the effects of damage under certain loading conditions, is investigated. An improved deactivation algorithm is developed for both damaged elasticity and coupled elastoplasticity formulations. The applicability of coupled formulations is validated by comparing theoretical predictions to experimental data for a spectrum of materials and loads paths. The pressure-dependent brittle-to-ductile transitional behavior of concrete is replicated. The deactivation algorithm is validated using tensile and compression data for concrete. For a ductile material, the behavior of an aluminum alloy is simulated including the temperature-dependent ductile-to-brittle behavior features. The direct application of a coupled model to fatigue is introduced. In addition, the deactivation algorithm in conjunction with an assumed initial damage and strain is introduced as a novel method of simulating the densification phenomenon in cellular solids.

Target recognition requires the ability to distinguish targets from non-targets, a capability called one-class generalization. Many neural network pattern classifiers fail as one-class classifiers because they use open decision boundaries. To function as one-class classifier, a neural network must have three types of generalization: within-class, between-class, and out-of-class. We discuss these three types of generalization and identify neural network architectures that meet these requirements. We have applied our one-class classifier ideas to the problem of automatic target recognition in synthetic aperture radar. We have compared three neural network algorithms: Carpenter and Grossberg`s algorithmic version of the Adaptive Resonance Theory (ART-2A), Kohonen`s Learning Vector Quantization (LVQ), and Reilly and Cooper`s Restricted Coulomb Energy network (RCE). The ART 2-A neural network gives the best results, with 100% within-class, between-class, and out-of-class generalization. Experiments show that the network`s performance is sensitive to vigilance and number of training set presentations.

This report discusses the seventh experiment of the Integral Effects Test (IET-7) series. The experiment was conducted to investigate the effects of preexisting hydrogen in the Surtsey vessel on direct containment heating. Scale models of the Zion reactor pressure vessel (RPV), cavity, instrument tunnel, and subcompartment structures were constructed in the Surtsey Test Facility at Sandia National Laboratories. The RPV was modeled with a melt generator that consisted of a steel pressure barrier, a cast MgO crucible, and a thin steel inner liner. The melt generator/crucible had a hemispherical bottom head containing a graphite limitor plate with a 4-cm exit hole to simulate the ablated hole in the RPV bottom head that would be formed by ejection of an instrument guide tube in a severe nuclear power plant accident. The cavity contained 3.48 kg of water, and the containment basement floor inside the cranewall contained 71 kg of water, which corresponds to scaled condensate levels in the Zion plant. A 43-kg initial charge of iron oxide/aluminum/chromium thermite was used to simulate corium debris on the bottom head of the RPV. Molten thermite was ejected by steam at an initial pressure of 5.9 MPa into the reactor cavity.

Charpy V-notch specimens (ASTM Type A) and 5.74-mm diameter tension test specimens of the Shippingport Reactor Neutron Shield Tank (NST) (outer wall material) were irradiated together with Charpy V-notch specimens of the Oak Ridge National Laboratory (ORNI), High,, Flux Isotope Reactor (HFIR) vessel (shell material), to 5.07 {times} 10{sup 17} n/cm{sup 2}, E > 1 MeV. The irradiation was performed in the Ford Nuclear Reactor (FNR), a test reactor, at a controlled temperature of 54{degrees}C (130{degrees}F) selected to approximate the prior service temperatures of the cited reactor structures. Radiation-induced elevations in the Charpy 41-J transition temperature and the ambient temperature yield strength were small and independent of specimen test orientation (ASTM LT vs. TL). The observations are consistent with prior findings for the two materials (A 212-B plate) and other like materials irradiated at low temperature (< 200{degrees}C) to low fluence. The high radiation embrittlement sensitivity observed in HFIR vessel surveillance program tests was not found in the present accelerated irradiation test. Response to 288{degrees}C-168 h postirradiation annealing was explored for the NST material. Notch ductility recovery was found independent of specimen test orientation but dependent on the temperature within the transition region at which the specimens were tested.

A method is presented for determining the nonlinear stability of undamped flexible structures spinning about a principal axis of inertia. Equations of motion are developed for structures that are free of applied forces and moments. The development makes use of a floating reference frame which follows the overall rigid body motion. Within this frame, elastic deformations are assumed to be given functions of n generalized coordinates. A transformation of variables is devised which shows the equivalence of the equations of motion to a Hamiltonian system with n + 1 degrees of freedom. Using this equivalence, stability criteria are developed based upon the normal form of the Hamiltonian. It is shown that a motion which is spin stable in the linear approximation may be unstable when nonlinear terms are included. A stability analysis of a simple flexible structure is provided to demonstrate the application of the stability criteria. Results from numerical integration of the equations of motion are shown to be consistent with the predictions of the stability analysis. A new method for modeling the dynamics of rotating flexible structures is developed and investigated. The method is similar to conventional assumed displacement (modal) approaches with the addition that quadratic terms are retained in the kinematics of deformation. Retention of these terms is shown to account for the geometric stiffening effects which occur in rotating structures. Computational techniques are developed for the practical implementation of the method. The techniques make use of finite element analysis results, and thus are applicable to a wide variety of structures. Motion studies of specific problems are provided to demonstrate the validity of the method. Excellent agreement is found both with simulations presented in the literature for different approaches and with results from a commercial finite element analysis code. The computational advantages of the method are demonstrated.

We describe an algorithm for the static load balancing of scientific computations that generalizes and improves upon spectral bisection. Through a novel use of multiple eigenvectors, our new spectral algorithm can divide a computation into 4 or 8 pieces at once. These multidimensional spectral partitioning algorithms generate balanced partitions that have lower communication overhead and are less expensive to compute than those produced by spectral bisection. In addition, they automatically work to minimize message contention on a hypercube or mesh architecture. These spectral partitions are further improved by a multidimensional generalization of the Kernighan-Lin graph partitioning algorithm. Results on several computational grids are given and compared with other popular methods.

A robotic rover vehicle designed for use in the exploration of the Lunar surface is described. The Robotic All-Terrain Lunar Exploration Rover (R-A.T.L.E.R-) is a four wheeled all-wheel-drive dual-body vehicle. A uniquely simple method of chassis articulation is employed which allows all four wheels to remain in contact with the ground, even while climbing over step-like obstacles as large as [approximately]1.3 wheel diameters. Skid steering and modular construction are used to produce a simple, rugged, highly agile mobility chassis with fewer parts required compared to other designs being considered for planetary exploration missions. The design configuration, mobility parameters, and performance of several existing R.A.T.L.E.R prototypes are discussed, with emphasis on an analysis of the configuration parameters which directly affect the designs mobility performance.

This report describes preliminary experiments to investigate the feasibility of using electron beam (e-beam) radiolysis to destroy the organic compounds in simulated Hanford tank waste. For these experiments a simulated Hanford Tank 101-SY waste mixture was radiolyzed in a {sup 60}Co facility to simulate radiolysis in the waste tank. This slurry was then exposed without dilution to dose levels up to 1600 Mrad at instantaneous dose rates of 2.5 {times} 10{sup 8} and 2. 7 {times} 10{sup 11} rad/s. The inferred dose to destroy all the organic material in the simulated waste, assuming destruction is linear with dose, is 1000 Mrads for the higher dose rate. The cost for organic destruction of Hanford waste at a treatment rate of 20 gpm is roughly estimated to be $10. 60 per gallon. Such a system would treat all the waste in a 1 million gallon Hanford tank in about 40 days. Estimates of capital costs are given in the body of this report. While ferrocyanide destruction was not experimentally investigated in this work, previous experiments by others suggest that ferrocyanide would also be destroyed in such a system.

This report describes the Training and Qualification Program at the Saturn Facility. The main energy source at Saturn is the Saturn accelerator which is used to test military hardware for vulnerability to X-rays, as well as to perform various types of plasma radiation source experiments. The facility is operated and maintained by a staff of twenty scientists and technicians. This program is designed to ensure these personnel are adequately trained and qualified to perform their jobs in a safe and efficient manner. Copies of actual documents used in the program are included as appendices. This program meets all the requirements for training and qualification in the DOE Orders on Conduct of Operations and Quality Assurance, and may be useful to other organizations desiring to come into compliance with these orders.

Experiments were run to determine if oxidized Kovar could be chemically cleaned so that copper would wet the Kovar in a wet hydrogen atmosphere at 1100{degrees}C. We found that a multi-stepped acid etch process cleaned the Kovar so that copper would wet it. We also found that the degree of copper cracking after melting and cool-down correlated well with the degree of wetting.

The relatively thin web of salt that separates Bayou Choctaw Caverns 15 and 17 was evaluated using the finite-element method. The stability calculations provided insight as to whether or not any operationrestrictions or recommendations are necessary. Because of the uncertainty in the exact dimensions of the salt web, various web thicknesses were examined under different operating scenarios that included individual cavern workovers and drawdowns. Cavern workovers were defined by a sudden drop in the oil side pressure at the wellhead to atmospheric. Workovers represent periods of low cavern pressure. Cavern drawdowns were simulated by enlargening the cavern diameters, thus decreasing the thickness of the web. The calculations predict that Cavern 15 dominates the behavior of the web because of its larger diameter. Thus, giventhe choice of caverns, Cavern 17 should be used for oil withdrawal in order to minimize the adverse impacts on web resulting from pressure drops or cavern enlargement. From a stability point of view, maintaining normal pressures in Cavern 15 was found to be more important than operating the caverns as a gallery where both caverns are maintained at the same pressure. However, during a workover, it may be prudent to operate the caverns under similar pressures to avoid the possibility of a sudden pressure surge at the wellhead should the web fail.

A feasibility study for developing an improved tool and improved models for performing event assessments is described. The study indicates that the IRRAS code should become the base tool for performing event assessments, but that modifications would be needed to make it more suitable for routine use. Alternative system modeling approaches are explored and an approach is recommended that is based on improved train-level models. These models are demonstrated for Grand Gulf and Sequoyah. The insights that can be gained from importance measures are also demonstrated. The feasibility of using Individual Plant Examination (IPE) submittals as the basis for train-level models for precursor studies was also examined. The level of reported detail was found to vary widely, but in general, the submittals did not provide sufficient information to fully define the model. The feasibility of developing an industry risk profile from precursor results and of trending precursor results for individual plants were considered. The data sparsity would need to be considered when using the results from these types of evaluations, and because of the extremely sparse data for individual plants we found that trending evaluations for groups of plants would be more meaningful than trending evaluations for individual plants.

The discrete Fourier transform (DFT) is used frequently used in the computation of the signal-to-noise ratio (SNR) and harmonic distortion. To estimate the SNR or harmonic distortion, a sine wave is applied to the digitizing system under test. When the data record contains an integer number of cycles of the sine wave, energy from the sine wave and its harmonics does not leak into adjacent DFT frequency bins. Each harmonic occupies one an only one DFT frequency bin. To find the root-mean-square (RMS) value of a harmonic from its DFT, one computes the magnitude of the DFT value at the single frequency of the harmonic. When the DFTs of the fundamental and its harmonics are single lines, the SNR and harmonic distortion are easy to compute. When the data record contains a non-integer number of cycles of the sine wave, energy leaks from the sine wave and its harmonics to adjacent frequencies. The literature contains several approaches to problem of determining which DFT components correspond to a sine wave harmonic. This paper describes how to estimate the RMS value of a sine wave from its DFT with special attention to the selection of the DFT window. The set of DFT frequencies which comprise a harmonic depends on the DFT window, the length of the DFT, and the number of bits of the digitizer. Criteria are developed for choosing the DFT frequencies that correspond to a sine wave. These criteria lead to better choices of DFT windows for SNR and harmonic distortion calculations.

Sandia has developed an advanced operational control system approach, caged Graphical Programming, to design and operate robotic waste cleanup and other hazardous duty robotic systems. The Graphical Programming approach produces robot systems that are faster to develop and use, safer in operation, and cheaper overall than altemative teleoperation or autonomous robot control systems. The Graphical Programming approach uses 3-D visualization and simulation software with intuitive operator interfaces for the programming and control of complex robotic systems. Graphical Programming Supervisor software modules allow an operator to command and simulate complex tasks in a graphic preview mode and, when acceptable, command the actual robots and monitor their motions with the graphic system. Graphical Progranuning Supervisors maintain registration with the real world and allow the robot to perform tasks that cannot be accurately represented with models alone by using a combination of model and sensor-based control. This paper describes the Graphical Programming approach, several example control systems that use Graphical Programming, and key features necessary for implementing successful Graphical Programming systems.

Hazardous operations which in the past have been completed by technicians are under increased scrutiny due to high costs and low productivity associated with providing protective clothing and environments. As a result, remote systems are needed to accomplish many hazardous materials handling tasks such as the clean up of waste sites in which the exposure of personnel to radiation, chemical, explosive, and other hazardous constituents is unacceptable. Traditional remote manual operations have proven to have very low productivity when compared with unencumbered humans. Computer models augmented by sensing and structured, modular computing environments are proving to be effective in automating many unstructured hazardous tasks.

Testing and analysis of shock wave characteristics such as produced by detonators and ground shock propagation frequently require a method of measuring velocity and displacement of the surface of interest. One method of measurement is doppler interferometry. The VISAR (Velocity Interferometer System for Any Reflector) uses doppler interferometry and has pined wide acceptance as the preferred tool for shock measurement. An important asset of VISAR is that it measures velocity and displacement non intrusively. The conventional VISAR is not well suited for portability because of its sensitive components, large power and cooling requirements, and hazardous laser beam. A new VISAR using the latest technology in solid state lasers and detectors has been developed and tested. To further enhance this system's versatility, the unit is fiber optic coupled which allows remote testing, permitting the VISAR to be placed over a kilometer away from the target being measured. Because the laser light is contained in the fiber optic, operation of the system around personnel is far less hazardous. A software package for data reduction has also been developed for use with a personal computer. These new advances have produced a very versatile system with full portability which can be totally powered by batteries or a small generator. This paper describes the solid state VISAR and its peripheral components, fiber optic coupling methods and the fiber optic coupled sensors used for sending and receiving laser radiation.

Thick film Au metallizations are commonly used as conductors in hybrid microelectronics that operate at high frequencies. Discrete components are attached to these conductors with 5OPb/5OIn solder. Intermetallic compounds form and grow in the solid state with time; AuIn[sub 2] is the primary compound formed in the Au-5OPb/50In system. A hybrid failed after being artificially aged to consume all of the Au and then subjected to normal thermal cycle and vibration testing. Postmortem analysis revealed that three capacitors had debonded. The failed parts were studied to determine the failure mechanism(s) and define a parametric study to characterize the mechanisms that bond the Au thick film to the ceramic substrate.

This is a peer review report of the Environmental and Molecule Sciences Laboratory. Although the Pretreatment, Treatment, and Waste Forms comments are focused specifically on pretreatment treatment, and waste forms, the group recognizes that the life cycle designation is a somewhat arbitrary breakdown of a series of activities that form a continuum in the environmental restoration and waste management program. Consequently, some of the comments made here are relevant in a broader context or even for EM as a whole. particular, characterization activities pervade all life cycles in environmental restoration/waste management. As we use the term in this section, characterization'' refers to the process monitoring and control that are required during pretreatment and treatment. Most of the technology presentations during the review identified links to support this area and delineated to varying degrees the specific ties to the Hanford Site cleanup requirements. Overall, the EMSL especially its planned facilities, are most impressive, and DOE and PNL are urged to proceed with all due haste toward its completion. Specific issues or concerns identified during the review are included in the following section.

Scientific visualization is playing an increasingly important role in the analysis and interpretation of massively parallel CFD simulations due to the enormous volume of data that can be generated on these machines. In this paper we will describe the development of a visualization technique based on a parallel analogue to the Marching Cubes algorithm. The algorithm has been developed for Multiple-Instruction, Multiple-Data (MIMD) massively parallel computers and is designed to take advantage of the heterogeneous programming capabilities of the MIMD architecture. We examine several different configurations and conclude that for producing animations the best one, in terms of both frame generation time and disk usage, is to run the two applications heterogeneously and send the resulting geometry description directly to a workstation for rendering, thereby totally eliminating the use of files from the animation process.

Sandia National Laboratories is prototyping a service for providing a distributed visualization capability between its Albuquerque, New Mexico and Livermore, California sites. The service will allow TCP/EP LAN users to process computationally intensive codes on the Cray Y-MP 8/864 and use the Application Visualization System, (AVS) running on a visualization server to display the results to desktops in Livermore (or Albuquerque). The long-haul environment presents several technical challenges such as high delays (up to 42 milliseconds), potential error rates, and security concerns which can affect the quality of the services. The network design requires low latency switch gear and high speed LAN connections (FDDI) to make the visualization/computational services useful to the customer. This paper will describe tie network design used and will report performance characteristics of the applications utilizing this service.

AC impedance and x-ray diffraction measurements versus temperature and pressure ternary intercalation compounds are reported. Results support our previously established empirical correlation between superconducting onset temperature and 300K fcc lattice constant. Compounds which do not follow this correlation either phase separate or are otherwise unstable at low T and/or high P.

We have demonstrated removal of H from a H-passivated Si(100) surface by low energy ([approximately]50 eV) He ion bombardment. The extent of the removal of H from the surface can be controlled by varying the duration of He bombardment and plasma parameters. This, in turn, means that the growth rate by this method can also be controlled. Si[sub 2]H[sub 6] was shown to adsorb in a self-limiting manner on the Si(100) surface.

The earth`s ionosphere consists of an ionized plasma which will interact with any electromagnetic wave propagating through it. The interaction is particularly strong at vhf and uhf frequencies but decreases for higher microwave frequencies. These interaction effects and their relationship to the operation of a wide-bandwidth, synthetic-aperture, space-based radar are examined. Emphasis is placed on the dispersion effects and the polarimetric effects. Results show that high-resolution (wide-bandwidth) and high-quality coherent polarimetrics will be very difficult to achieve below 1 GHz.

SAFSIM (System Analysis Flow SIMulator) is a FORTRAN computer program that provides engineering simulations of user-specified flow networks at the system level. It includes fluid mechanics, heat transfer, and reactor dynamics capabilities. SAFSIM provides sufficient versatility to allow the simulation of almost any flow system, from a backyard sprinkler system to a clustered nuclear reactor propulsion system. In addition to versatility, speed and robustness are primary goals of SAFSIM development. The current capabilities of SAFSIM are summarized and some sample applications are presented. It is applied here to a nuclear thermal propulsion system and nuclear rocket engine test facility.

Photovoltaic (PV) systems offer a cost-effective solution to provide electrical power for a wide variety of applications, with battery performance playing a major role in their success. This paper presents some of the results of an industry meeting regarding battery specifications and ratings that photovoltaic system designers require, but do not typically have available to them. Communications between the PV industry and the battery industry regarding appropriate specifications have been uncoordinated and poor in the past. This paper also discusses the effort under way involving the PV industry and battery manufacturers, and provides a working draft of specifications to develop and outline the information sorely needed on batteries. The development of this information is referred to as ``Application Notes for Batteries in Photovoltaic Systems.`` The content of these ``notes`` has been compiled from various sources, including the input from the results of a survey on battery use in the photovoltaic industry. Only lead-acid batteries are discussed

In one design of molten-salt central receivers, the molten salt flows in a serpentine path, down one panel of tubes then up the next and down again continuing in this fashion through the receiver. There have been concerns about this design because in the down flow sections, the heat flux incident on the tubes can cause flow instability since the flow is in direct opposition to the buoyant forces. In extreme cases the buoyant forces can cause flow stagnation or reversal. An analysis of flow stability within individual tubes and down flow sections of receiver panels is presented. When the partial derivative of the pressure drop with respect to mass flow rate is negative ({partial_derivative}{Delta}P/{partial_derivative}{sup {lg_bullet}} < 0), the flow is unstable and could cause serious damage to the receiver. Stability maps are developed that show safe operating regimes where inertial forces dominate over buoyant forces. The data is then normalized using the Grashof and Reynolds numbers.

United States Department of Energy has established its first Advanced Research Objective in the Solids Transport Program. The scientific, engineering, and management goals are discussed in some detail. Scientific progress to date is summarized. Comments are made on the technical direction of further Advanced Research Objectives.

We have developed a Li/SOCl{sub 2} ``D`` cell for applications requiring 10 to 15 years life at very low drain rates, typically less than 150 {mu}A. Maximizing cell safety and reliability, while delivering very good energy density, have been the goals of our study. We have achieved these goals by designing the cell to be application specific. The low-rate cell has been optimized to deliver up to 16 Ah at drain rates of less than 70 mA. By virtue of its low surface area, 145 cm{sub 2}, the cell has demonstrated excellent safety behavior. Safety testing has been performed on individual cells as well as on two-cell and four-cell batteries. Single cells did not vent when short-circuited. We were able to produce benign venting in a two cell string, but only when the string was partially discharged before shorting. The vent mechanism is a 300 psi rupture pressure burst disc manufactured by BS&B Safety Systems. We define benign venting as full opening of the 3/8 in. dia vent hole without deformation of the case. Material is expelled from the cell without flame, and the cell stack remains largely intact. We have not produced venting of the Sandia-designed low rate cell under any other abuse test conditions. The vent functions as an ultimate safety mechanism in the case of severe abuse, but resistance to venting under normal use and mild abuse conditions is key to the achievement of high reliability.

A new class of ion-exchange materials that can selectively separate low parts per million level concentrations of Cs{sup +} from 3--6 molar concentrations of Na{sup +} over a wide pH range has recently been developed as a result of a collaborative effort between Sandia National Laboratories and Texas A&M University. The materials, called crystalline silicotitanates, show potential for application in the treatment of aqueous nuclear waste solutions.

In order to develop a procedure for measuring cation diffusion coefficients below 1000{degrees}C, we have examined the suitability of several diffusion couple configurations involving single crystals of garnet. Initial experiments using an enriched {sup 25}MgCl{sup 2} proved ineffective in providing a uniform and coherent surface for analysis by ion microprobe. A technique was developed using thin film deposition. Thin films ({approximately} 1000 {Angstrom}) of MgO{sub x} (x < 1) can be applied to polished mineral surfaces by evaporating MgO powder under high vacuum with a thermal-resistance strip heater. Thermal resistance evaporation is efficient. Samples of single crystal grossular and pyrope garnets with thin films of MgO, as created by these techniques, were annealed for various times at 800, 900, and 1000{degrees}C, at several log fO{sub 2} values, and 1 atm. Optical, SEM, and ion microprobe analyses reveal no disruption of the interface. Profiles of elemental counts vs depth exhibit expected patterns going through the thin film into the garnet substrate. Our experimental matrix of garnet diffusion runs includes over 60 cut and polished crystals of pyrope composition that are being run at various oxygen fugacity conditions from 600 to 1000{degrees}C.

The Los Alamos National Laboratory (LANL) Mechanical Engineering and Electronics Division, in partnership with Sandia National Laboratories and Programmed Composites, is advancing the development of thin-walled, high modulus short-fiber compression-molded composite materials fabrication. In this paper, we investigate component uniformity, structural integrity, thermal conductivity, and radiation resistance; discuss the scanning-electron microscopic inspection of the graphite fiber distribution and orientation, and describe the process used in selecting the reinforcement fiber length and modulus and for choosing the hydrophobic, cyanate-ester resin.

During the last two decades there has been considerable interest in developing alternatives to conventional chemical propulsion for space missions. Laser propulsion has been identified as a serious contender for the task of inexpensively delivering small payloads to low-earth orbit. Recent advances in the development of lasers powered directly by nuclear reaction products offer the potential for new propulsion methods, namely, reactor-laser propulsion. Such systems would allow ``nuclear propulsion`` without placing nuclear systems in space.

Alternate organometallic Sb sources are being investigated to improve the characteristics of InSb grown by MOCVD. InSb grown using trimethylindium (TMIn) and trimethylantimony (TMSb) or triethylantimony (TESb) yielded similar quality materials under similar growth conditions. InSb grown using triethylindium (TEIn) and TESB under similar growth conditions yielded very poor quality n-type material. Three new organometallic Sb sources, triisopropyl-antimony (TIPSb), tris(dimethylamino)antimony (TDMASb), and tertiarybutyldimethylantimony (TBDMSb) are being investigated. Growth of InSb using TIPSb, TDMASb, or TBDMSb and TMIn was investigated over 350 to 475{degrees}C. InSb grown from TDMASb had similar properties to InSb grown from TMIn and TMSb when using a similar temperature and V/III ratio range. Growth rates of InSb using TMIn and either TIPSb or TBDMSb at temperatures {le} 425{degrees}C were proportional to both TMIn flow rate and temperature. Surface morphology of InSb grown using either TIPSb or TBDMSb was rough for growth temperatures {le} 425{degrees}C; this may be due to complex decomposition and methyl groups on surface. The InSb with the highest mobility was grown at 400{degrees}C and a V/III ratio of 3 using TIPSb. It was n-type with a carrier concentration of 2.5 {times} 10{sup 15} cm{sup {minus}3} and a mobility of 78,160 cm{sup 2}/Vs at 77 K. Both n- and p-type InSb were grown using TBDMSb with mobilities up to 67,530 and 7773 cm{sup 2}/Vs, respectively at 77 K. Mobility for InSb using either TIPSb or TBDMSb was optimized by going to lower temperatures, pressures, V/III ratios; however, surface morphology improved with higher temperature, pressure, V/III ratio. High mobility InSb with smooth surfaces at T {le} 425{degrees}C was not obtained with TIPSb or TBDMSb and TMIn.

We present the use of an STM to make quantitative observations of time-dependent mass flow associated with the decay of two-dimensional clusters on the Au(lll) surface. When formed and observed in air, layered islands with well-defined edges located on larger terraces are generally found to decay in such a way that their areas decrease linearly in time over periods ranging from minutes to several hours depending on the island size. This is in contrast to the behavior of similar features formed and observed under ultra high vacuum conditions, which do not appear to decay over experimental periods of several days. The linear decay is consistent with models that have been used previously to describe growth of 2-dimensional clusters on surfaces. We discuss possible decay mechanisms`, and the role that adsorbates may play in influencing the decay.

In support of the UST, WeDID, VOC/Non-Arid, and VOC/Arid, and VOC/Arid Integrated Demonstrations, organic contaminants and nitrates in Hanford Underground Storage Tank (UST) wastes, polymeric organics in weapon components, and chlorocarbon soil contaminants have been destroyed by exposure to high-temperature steam during bench tests with a quartz reactor and full-scale tests that used the Synthetica Detoxifier, a commercial one-ton-per-day steam reforming waste destruction system. Reactivation of Granular Activated Carbon (GAC) in the Detoxifier and Thermal Gravimetric Analyses (TGA) of the decomposition of sodium nitrate have also been performed.

We have successfully grown ZnMnTe alloys by molecular beam epitaxy using GaAs as a substrate. Bulk MnTe has the wurtzite crystal structure but the structural phase of the material was confirmed to be zinc-blende by standard {theta}-2{theta} x-ray diffraction techniques. The composition was also determined using x-ray diffraction techniques. Manganese concentration was also estimated from magnetization measurements taken as a function of temperature. Magnetoluminescence studies were performed at 1.4K on the acceptor-bound exciton in the semimagnetic semiconductor ZnMnTe alloys. As expected, the photoluminescence peak energy decreased with increasing magnetic field.

At some landfills, hazardous wastes were placed into disposal pits with other waste oils. Volatile organic wastes, such as cleaning solvents, when combined with oil are much more difficult to remove from the soils because the oil makes the volatile organic chemical evaporate much slower. The typical vacuum extraction remediation method could become a lengthy campaign. Since all chemicals evaporate faster when they are heated, if the contaminated soil could be heated, the chemicals would be easier to remove from the soil. By using heating techniques developed by the Oil and Gas Industry to enhance the removal of oil and gas resources from the soil, the problem of removing contamination from the soils could be solved. The Thermal Enhanced Vapor Extraction System (TEVES) demonstration will combine vacuum vapor extraction technology with powerline frequency soil heating and radiofrequency soil heating to accelerate the soil decontamination process. The premise that soil heating technology can actually reduce the costs of soil decontamination is complicated by the high capital costs of the soil heating equipment and the cost of electrode installation. By performing this field demonstration, Sandia will be able to collect the information needed to see if this new technology will improve the decontamination of soils.

Sandia National Laboratories is a large multiprogram Research and Development laboratory which is operated by a contractor for the US Department of Energy. In the Laboratories, lasers are both the subject of research and the tools that are used in other research, development, and testing activities. Since 1979, laser safety training has been the primary focus of the Laboratories` laser safety program. Approximately 1 100 personnel have been trained in formal courses during that time period. The formal course, presented on site by a contractor, consists of two full days of instruction. The course contents include the following topics: Laser technology and safety overview; Federal and ANSI laser standards summaries; Biological effects of laser radiation; Classification of lasers; Laser hazard analysis; Review of ANSI Z136.1 control measures; Laser eye protection. Recent emphasis on regulatory requirements, conduct of operations, and quality management has revealed a need to change the laser safety training curriculum. A new course for users of low power lasers (Class 2 and 3a) is being developed. A refresher course, a management awareness (self-study) course, and major changes in the current course are planned.

Short communication.

A solar photocatalytic process has been under development at both Sandia National Laboratories and the National Renewable Energy Laboratory (formerly the Solar Energy Research Institute). This process uses solar ultraviolet light to activate a titanium dioxide catalyst which oxidizes organic contaminants in water. In the summer of 1991, a solar photocatalytic detoxification of water system was installed and tested at a California Superfund Site located at Lawrence Livermore National Laboratory. The site was designated a Superfund Site because of widespread groundwater contamination which resulted from the release of chlorinated solvents, principally trichloroethylene, when the site was a Naval Air Station in the early 1940s. The objectives of these experiments were to measure the effects of process variables and the process efficiency in an actual remediation setting, to collect experimental data and operating experience in photocatalytic oxidation of organic contaminants, to develop accurate models of the system operation and to develop control strategies.

The Materials Interface Interaction Tests (MIIT) program involves the comparative performance-evaluation testing of multiple US and foreign nuclear waste glasses (nonradioactive), potential canister and overpack metals, brine, and geologic materials in the rock salt repository environment at the Waste Isolation Pilot Plant (WIPP) facility. We emplaced about 2000 materials specimens onto fiftn, separate test assemblies and exposed them to a heated, salt-brine environment at the WIPP for multi-year periods. We successfully terminated the in situ conduct of the MIIT in July 1991, after five years of testing, and retrieved all samples for posttest laboratory analyses. These 5-year glass and metal samples, along with samples previously retrieved after 0.5, 1, and 2 years, are being analyzed in multiple international laboratories, in a cooperative testing effort. Individual test participants will present available laboratory results, and interpretations, on MIIT specimens in this workshop. Our focus in this paper is to summarize technical details and repository-relevant observations on the in situ conduct, sampling, and termination operations of the MIIT experimental program. Such information should be useful for the interpretation of the laboratory-based analyses. This information also will be relevant and instructive for other organizations contemplating, planning, or conducting additional materials-related, in situ tests.

A comparison between numerical calculations with use of commercial thermal analysis software packages and experimental data simulating a horizontally oriented spent fuel rod array was performed. Twelve cases were analyzed using air and helium for the fill gas, with three different heat dissipation levels. The numerically predicted temperatures are higher than the experimental data for all levels of heat dissipation with air as the fill gas. The temperature differences are 4{degree}C and 23{degree}C for the low heat dissipation and high heat dissipation, respectively. The temperature predictions using helium as a fill gas are lower than the experimental data for the low and medium heat dissipation levels. The temperature predictions are 1{degree}C and 6{degree}C lower than the experimental data for the low and medium heat dissipation, respectively. For the high heat dissipation level, the temperature predictions are 16{degree}C higher than the experimental data. Differences between the predicted and experimental temperatures can be attributed to several factors. These factors include experimental uncertainty in the temperature and heat dissipation measurements, actual convection effects not included in the model, and axial heat flow in the experimental data. This work demonstrates that horizontally oriented spent fuel rod surface temperature predictions can be made using existing commercial software packages. This work also shows that end effects, such as axial heat transfer through the spent fuel rods, will be increasingly important as the amount of dissipated heat increases.

Magnetic force microscopy (MFM) has been applied to image currents in internal IC conductors. We present a model for the MFM imaging of IC currents, describe MFM signal generation, and demonstrate the ability to analyze current direction and magnitude with a sensitivity of {approximately} 1 mA dc and {approximately} 1 {mu}A ac. Our experimental results are a significant improvement on the 100 mA ac resolution previously reported using an electron beam to detect IC currents [1].

The Waste Isolation Pilot Plant: (WIPP) in southeastern New Mexico is being developed by the US Department of Energy as a disposal facility for transuranic waste. In support of this project, Sandia National Laboratories is conducting an ongoing performance assessment (PA) for the WIPP. The ordered triple- representation for risk proposed by Kaplan and Garrick is used to provide a clear conceptual structure for this PA. This presentation describes how the preceding representation provides a basis in the WIPP PA for (1) the definition of scenarios and the calculation of scenario probabilities and consequences, (2) the separation of subjective and stochastic uncertainties, (3) the construction of the complementary cumulative distribution functions required in comparisons with the US Environmental Protection Agency`s standard for the geologic disposal of radioactive waste (i.e., 40 CFR Part 191, Subpart B), and (4) the performance of uncertainty and sensitivity studies. Results obtained in a preliminary PA for the WIPP completed in December of 1991 are used for illustration.

Short communication.

As applications for hybrid circuits and multichip modules create demand for higher density circuits and higher power components, new substrate materials are required to deal with the heat generated on the circuit. Sandia National Laboratories is developing diamond substrate technology to meet the requirements of high thermal conductivity. Thin film processes were developed and characterized to delineate conductor-resistor networks on free standing diamond substrates having fine line gold conductors and low and high sheet resistivity resistors. Thin film hybrid circuit technology was developed on CVD-processed, polycrystalline diamond substrates having as-deposited surface finishes as well as those with polished surfaces. Conductors were defined by pattern plating gold and resistors were processed from sputtered tantalum nitride films which were deposited to sheet resistivities of 5 and/or 100 ohms per square. Resistor films on diamond substrates were evaluated for Temperature Coefficient of Resistance (TCR), stability with time and temperature, and trimmability using YAG laser processing. Plated gold conductors were patterned on diamond to feature sizes of 25 microns and successfully tested for adhesion and bondability. Advanced YAG laser trimming techniques were developed to allow resistor trims on both low and high value resistors to within 1% of desip value while maintaining required resistor stability, new trim techniques were needed to offset the carbonization of diamond in the laser trim area. Reliability studies were carried out on the diamond thin film networks which showed them to compare favorably with the same thin film technology on alumina substrates.

Photocreation mechanisms and properties of nitrogen dangling bonds in amorphous hydrogenated silicon nitride (a-SiN{sub x}:H) thin films are investigated. We find that the creation kinetics are strongly dependent on the post-deposition anneal; this thermal process can be described by a simple exponential function which yields an activation energy of 0.8 eV. The compositional dependence of the nitrogen dangling bond center suggests that its energy level lies close to the valence band edge, in agreement with theoretical calculations. This energy level position can explain why a-SiN{sub x}:H films often become conducting following a high post-deposition anneal.

Path planning needs to be fast to facilitate real-time robot programming. Unfortunately, current planning techniques are still too slow to be effective, as they often require several minutes, if not hours of computation. To overcome this difficulty, we present an adaptive algorithm that uses previous experience to speed up future performance. It is a learning algorithm suitable for incrementally-changing environments such as those encountered in manufacturing of evolving products and waste-site remediation. The algorithm extends our previous work for stationary environments in two directions: For minor environmental change, an object-attached experience abstraction scheme is introduced to increase the flexibility of the learned experience; for major environmental change, an on-demand experience repair scheme is also introduced to retain those experiences that remain valid and useful. In addition to presenting this algorithm, we identify three other variants with different repair strategies. To analyze the respective performance of these algorithms, we develop an analytic model that quantifies and relates training effort, experience value and utility, and environmental change through intuitive terms of energy and work. It is a general and simple model that should be very useful in characterizing other types of learning processes as well. Using this model, we formalize the concept of incremental change, and prove the optimality of our proposedalgorithm under such change. Empirically, we also characterize the performance curve of each variant, confirm our theoretical optimality results, and demonstrate the practicality of our algorithm.

A method of solving the two-phase fluid flow equations using a genetic algorithm on a NCUBE multiprocessor computer is presented. The topics discussed are the two-phase flow equations, the genetic representation of the unknowns, the fitness function, the genetic operators, and the implementation of the algorithm on the NCUBE computer. The efficiency of the implementation is investigated using a pipe blowdown problem. Effects of varying the genetic parameters and the number of processors are presented.

A method is described for parallelizing molecular dynamics (MD) simulations by block-decomposing the matrix of bonded and non-bonded force computations. It is particularly useful for organic simulations (polymers, proteins) because unlike spatial-decomposition methods, it requires no geometric information about the simulation domain. Because its communication cost scales as N/{radical}P. rather than N as in the all-to-all broadcast or ring-exchange techniques commonly used in this type of MD simulation, larger numbers of processors can be used effectively, yielding greater parallel speed-ups.

Two major initiatives are underway in the US that are creating a significant financial impact on both the US taxpayer and on users of electric power. First, the US Department of Energy (DOE) has been tasked with cleaning-up the defense complex. This task is managed under the direction of the Office of Environmental Restoration and Waste Management (EM) of the DOE. The waste that EM must address includes radioactive, hazardous, and mixed that consists of both radioactive and hazardous constituents. Second, the DOE is required by the Nuclear Waste Policy Act (NWPA) to take title to commercial nuclear spent fuel assemblies starting in 1998. The DOE Office of Civilian Radioactive Waste Management (OCRWM) was established to carry out this charter. Since a final repository is not scheduled for opening until 2010 at the earliest, the DOE is planning on providing a Monitored Retrievable Storage (MRS) facility for centralized storage to bridge the time gap between 1998 and 2010. The NWPA requires that nuclear utilities pay a fee into a specific fund that Congress uses to pay the DOE for the development of the MRS, the transportation system, and the repository. This fund, along with the EM budget, constitutes a multi-billion dollar effort to manage DOE nuclear waste and to store and dispose of commercial spent nuclear fuel. These two seemingly unrelated problems have aspects of commonality that can be considered for the benefit of both programs, the US taxpayer, and the utility rate payer. Both programs are the responsibility of the DOE, and both will require engineered packages for storage, transportation, and disposal of the EM waste and commercial spent fuel. Rather than using specialized systems for each step (storage, transport, and disposal), a concept for a Universal Container System has been developed that could potentially simplify the overall waste management system, reduce expensive handling operations, and reduce total system cost.

Inadvertent alloying of Cu braze metal can compromise metal/ceramic seals. Electron microprobe analyses have quantified alloying of Cu brazes in metal/ceramic feedthroughs. Pin material and processing parameters above 1084C both affect alloying levels. Using either Kovar or Ni-plated 316L stainless steel pins limits alloying compared to Palco pins. Minimizing the time during which the braze is molten also avoids excessive alloying. The original thickness of the Ni plating on the Mo-Mn metallization of the ceramic also influences the alloying content of these brazes. Metal/ceramic brazes made with long brazing cycles, Mo-Mn metallization, and Kovar components grow a layer of Mo{sub 6}(Fe{sub 3.5}CO{sub 3.5}){sub 7} on the metallization. Layer thicknesses observed do not appear to compromise joint integrity. Ni additions of approximately 10 and 20 wt.% to Cu apparently increases the stress required for stress relaxation during cooldown. to maintain creep rates required for stress relaxation during cooldown. Relative to unalloyed Cu, this strengthening effect tends to increase as temperature is decreased.

In this paper we investigate the applicability of the feature extraction mechanisms found in the neurophysiology of mammals to the problem of object recognition in synthetic aperture radar imagery. Our approach is to present multiple views of objects to be recognized to a two-stage self-organizing neural network architecture. The first stage, a two-layer Neocognitron, performs feature extraction in each layer The resulting feature vectors are presented to the second stage, an ART-2A classifier self-organizing neural network which clusters the features into multiple object categories. The feature extraction operators resulting from the self-organization process are compared to the feature extraction mechanisms found in the neurophysiology of vision. In a previous paper, the Neocognitron was trained on raw SAR imagery. The architecture was able to recognize a simulated vehicle at arbitrary azimuthal orientations at a single depression angle while rejecting clutter as well as other vehicles. Feature extraction on raw imagery yielded features that were robust but very difficult to interpret. In this paper we report the results of some new experiments in which the self-organization process is applied separately to shadow and bright returns from objects to be recognized. Feature extraction on shadow returns yield oriented contrast edge operators suggestive of bipartite simple cells observed in the striate cortex of mammals. Feature extraction on the specularity patterns in bright returns yield a collection of operators resembling a twodimensional Haar basis set. We compare the performance of the earlier two-stage neural network trained on raw imagery with a modified network using the new feature set.

The Mixed Waste Landfill Integrated Demonstration (MWLID) is testing noninvasive site characterization methods at several locations, including the Chemical Waste Landfill (CWL) at Sandia National Laboratories. The CWL comprises shallow, unlined pits that were used for the disposal of acids, oils, solvents, and inorganic compounds from 1962 until the CWL was closed in 1985. The soils of the landfills are alluvial, predominantly sand, gravels and cobbles with small quantities of silts and clays. The focus of this study is an unlined chromic acid pit (UCAP). The UCAP pit is rectangular (approximately 4 {times} 10 m), which reportedly received unknown volumes of chromium in the form of chromic acid (liquid) and other hazardous materials. At this location, we have demonstrated a continuous waveform (CW) system for site characterization. During this year, we will also utilize a crossborehole pulsed radar system. Both methods are sensitive to variations in either electrical conductivity or dielectric constant in the soils or host rock at a waste site. These earth properties are some of the most responsive geophysical indicators of metallic, acidic and water-based subsurface contaminants.

Using Saturn as a driver, we are pursuing both photoresonantly pumped and photoionization/recombination lasers. Our lasing targets are gas cells with thin windows that are pumped by a z pinch 2 cm away radiating 10 TW. In both schemes the lasant and gas fill is neon. To increase our chances of measuring the resonantly photopumped lasing transition we have introduced potassium into a sodium z pinch and have eliminated oxygen from the gas cell windows. We have measured the spatial dependence of ionization balance across the gas cell, and this measurement is consistent with propagation of a shock front across the gas cell target. We have measured blue-shifted satellites to several Li-like neon transitions that may indicate return-current driven jetting a high 1.5e8 cm/sec velocity. Using a gold z-pinch we have shown that key radiation is necessary to excite the He-like lines of neon. An attempt at a single shot gain measurement also indicates that radiation is not the only source of gas cell heating.

This paper presents a full-field dye concentration measurement technique that extends our experimental capabilities to the measurement of transient dye concentration fields within steady state flow fields under unsaturated or saturated conditions. Simple light absorption theory provides a basis for translating images into high resolution dye concentration fields. A series of dye pulse experiments that demonstrate the combined use of the full-field saturation and dye concentration techniques was conducted at four different degrees of saturation. Each of these experimental sequences was evaluated with respect to mass balance, the results being within 5% of the known dye mass input. An image windowing technique allowed us to see increased dispersion due to decreasing moisture content, tailing of concentration at the rear of the dye pulse and slight velocity changes of the dispersive front due to changes in moisture content. The exceptional resolution of dye concentration in space and time provided by this laboratory technique allows systematic experimentation for examining basic processes affecting solute transport within saturated/unsaturated porous media. Future challenges for this work will be to use these techniques to analyze more complex systems involving heterogeneities, scaling laws, and detailed investigations of the relationship between transverse and longitudinal dispersion in unsaturated media.

The Beam Characterization System is being employed at the Sandia`s National Solar Thermal Test Facility to characterize the optical performance of heliostats, point-focus solar collectors, and their optical sub-elements as part of the on-going task to develop solar thermal technologies. With this measurement system, images of concentrated solar flux are acquired using digital imaging and processed to obtain such measures of the collector`s optical performance as beam power, flux distribution, and beam diameter. Key system elements are a diffusely reflective target for imaging collector beams, meteorological instrumentation including a flux gauge to measure flux at one point in the beam, and a calibration technique to establish a pixel-intensity-to-flux-density conversion factor for the image. The system is employed in a variety of collector tests such as beam quality, tracking error, and wind effects. The paper describes the Beam Characterization System and its components and presents, for illustration, sample test results. An analysis of the Beam Characterization System`s sources of measurement error is presented. Lastly, measurement techniques that employ the BCS to align heliostats and to measure or estimate collector surface slope errors are described.

We have measured the laser emission spectra of several vertical cavity surface emitting lasers following pulsed laser excitation, with a time resolution of < 1 ps. Correlations between the observed pulse widths and cavity lifetimes were observed.

A series of constant strain rate, unconfined compression experiments was performed on saturated welded tuff specimens collected from Busted Butte near Yucca Mountain, Nevada. Twenty specimens were loaded to failure at strain rates ranging from 10{sup {minus}9}s{sup {minus}1} to 10{sup {minus}3}s{sup {minus}1}, under ambient pressure and temperature conditions. The strength of the specimens showed a continuous decrease with decreasing strain rate between 10{sup {minus}9} s{sup {minus}1} and 10{sup {minus}5} s{sup {minus}1}. At the highest strain rate, 10{sup {minus}3} s{sup {minus}1}, strengths were less than those observed at 10{sup {minus}5} s{sup {minus}1}, likely due to hydrofracturing within the specimen at rapid loading rates. Reduction in strength, corresponding to the decrease in strain rate, is explained in terms of stress corrosion cracking. A detailed examination of six specimens tested at a strain rate of 10{sup {minus}9} s{sup {minus}1}, using acoustic wave velocities and CT scans, shows a correlation between the nature of the microstructure of the specimens and the observed strengths and elastic moduli.