Publications

The status of nuclear materials in both the U.S. and Former Soviet Union is changing based upon the execution of agreements relative to weapons materials production and weapon dismantlement. The result of these activities is that a considerably different emphasis is being placed on how nuclear materials are viewed and utilized. Even though much effort is being expended on the final disposition of these materials, the interim need for storage and security of the material is increasing. Both safety and security requirements exist to govern activities when these materials are placed in storage. These requirements are intended to provide confidence that the material is not being misused and that the storage operations are conducted safely. Both of these goals can be significantly enhanced if technological monitoring of the material is performed. This paper will briefly discuss the traditional manual methods of U.S. and international material monitoring and then present approaches and technology that are available to achieve the same goals under the evolving environment.

Prioritizing waste generators is necessary to determine which are the best candidates for Pollution Prevention Opportunity Assessments (PPOAs). This paper describes the Sandia National Laboratories/New Mexico (SNL/NM) PPOA Ranking System. The system uses a multimedia approach that considers hazardous and radioactive waste disposal data, and hazardous chemical usage data (from which air emissions are extrapolated). Pollution prevention information is included, from the SNL Pollution Prevention Opportunities database that identifies waste streams that have readily apparent pollution prevention opportunities. The system also considers the relative costs of waste management and the chargeback fees paid for waste generation. From these data, organizations are ranked with an algorithm developed in Microsoft Access{trademark} on a personal computer. The concept could readily be transferred to other facilities needing to decide where to perform PPOAs.

Cost and schedule overruns are often caused by poor requirements that are produced by people who do not understand the requirements process. This report provides a high-level overview of the system requirements process, explaining types, sources, and characteristics of good requirements. System requirements, however, are seldom stated by the customer. Therefore, this report shows ways to help you work with your customer to discover the system requirements. It also explains terminology commonly used in the requirements development field, such as verification, validation, technical performance measures, and the various design reviews.

Parameter estimation for modern viscoplastic constitutive models often requires data from many tests. Sensitivity coefficients can be used to design an efficient test matrix and reduce testing requirements. The present study derives sensitivity coefficients for each model parameter in the Munson-Dawson constitutive model and evaluates them for several load histories.

Knowledge of the charge efficiency of lead-acid batteries near top-of-charge is important to the design of small photovoltaic systems. In order to know how much energy is required from the photovoltaic array in order to accomplish the task of meeting load, including periodic full battery charge, a detailed knowledge of the battery charging efficiency as a function of state of charge is required, particularly in the high state-of-charge regime, as photovoltaic systems are typically designed to operate in the upper 20 to 30% of battery state-of-charge. This paper presents the results of a process for determining battery charging efficiency near top-of-charge and discusses the impact of these findings on the design of small PV systems.

As the successor to SUNMOS [8], the Puma operating system provides a flexible, lightweight, high performance message passing environment for massively parallel computers. Message passing in Puma is accomplished through the use of a new mechanism known as a portal. Puma is currently running on the Intel Paragon and is being developed for the Intel TeraFLOPS machine. In this paper we discuss issues regarding the development of the Argonne National Laboratory/Mississippi State University implementation of the Message Passing Interface standard on top of portals. Included is a description of the design and implementation for both MPI point-to- point and collective communications, and MPI-2 one-sided communications.

The Nuclear Weapons Guidance Team is an interagency committee led by Earl Whiteman, DOE that chartered the generation of EP40100, Concurrent Qualification and its successor EP401099, Concurrent Engineering and Qualification. As this new philosophy of concurrent operations has evolved and as implementation has been initiated, conflicts and insufficiencies in the remaining Engineering Procedures (EPs) have become more apparent. At the Guidance Team meeting in November 1995, this issue was explored and several approaches were considered. It was concluded at this meeting, that a smaller set of interagency EPs described in a hierarchical system could provide the necessary interagency direction to support complex-wide implementation. This set consolidates many existing EP processes where consistency and commonality are critical to success of the extended enterprise. The Guidance Team subsequently chartered an interagency team to initiate development activity associated with the envisioned new EP set. This team had participation from seven Nuclear Weapons Complex (NWC) sites as well as DOE/AL and DP-14 (team members are acknowledged later in this report). Per the Guidance Team, this team, referred to as the Architecture Subcommittee, was to map out and define an EP Architecture for the interagency EPs, make recommendations regarding a more agile process for EP approval and suggest an aggressive timeline to develop the combined EPs. The Architecture Subcommittee was asked to brief their output at the February Guidance Team meeting. This SAND report documents the results of the Architecture Subcommittee`s recommendations.

Moessbauer spectroscopy has been used to determine the iron-bearing phases in the coal, catalysts, and IOM products used and generated in the Direct Coal Liquefaction (DCL) catalyst testing program at Sandia National Laboratories, New Mexico. DCL experiments were conducted with a Blind Canyon, Utah, coal both thermally and with three different iron-based catalysts: (1) a sulfated hematite catalyst (Fe{sub 2}O{sub 3}/SO{sub 4}{sup 2{minus}}), (2) a 6-line ferrihydrite catalyst, and (3) iron-oxide impregnated directly into coal. The catalysts were added to the coal at both a 0.5 and a 1.0 wt% level and sufficient sulfur was added to ensure complete sulfidation of the iron. The Moessbauer spectrum of the Blind Canyon coal revealed that the major iron-bearing mineral present was ankerite, Ca(Fe,Mg)(CO{sub 3}){sub 2}, which converts firs to {gamma}-Fe (austenitic iron) before undergoing partial sulfidation to pyrrhotite in the thermal runs. The percentages of pyrrhotite formed in the catalytic runs were higher than those in the thermal runs indicating that sulfidation of the added iron occurs more rapidly than with the ankerite. Moessbauer data on the amount of pyrrhotite present does not correlate well with THF and heptane conversion percentages, indicating that other parameters like catalyst dispersion must also be considered.

In this report the authors describe the methods they have developed for producing stable periodic mesoporous silica gels, thin films of mesoporous silica for sensor applications, a route to nonaqueous synthesis, and the use of various additives in controlling the pore size and structure of these materials. Mesoporous silica is formed by templating silica precursors around micelles of cationic quaternary ammonium surfactants. During the synthesis these micelles undergo a phase transition to a hexagonal, lamellar or cubic liquid crystalline state, thus imposing periodic order on the amorphous silica which occupies the interface of the hydrophilic cationic headgroups of the surfactants. The product of the bulk wet synthesis is a gel composed of micron size silica/surfactant particles, each of which consists of one or more crystalline domains of silica condensed around the surfactant template. The wet gel can then be washed and pyrolyzed to remove the surfactant template, yielding the periodic mesoporous silica product.

In an effort to establish joint activities in the disposition of fissile materials from nuclear materials, the US and Russia agreed to conduct joint work to develop consistent comparisons of various alternatives for the disposition of weapons-grade plutonium. Joint working groups were established for the analysis of alternatives for plutonium management for water reactors, fast reactors, storage, geological formations, immobilization and stabilization of solutions and other forms. In addition cross-cutting working groups were established for economic analysis and nonproliferation (NP). This paper reviews the activities of the NP working group in support of these studies. The NP working group provided integrated support in the area of nuclear NP to the other US/Russian Study teams. It involved both domestic safeguards and security and international safeguards. The analysis of NP involved consideration of the resistance to theft or diversion and resistance to retrieval, extraction or reuse.

Polymer-based routes to ceramic oxides take advantage of precursor chemistry and structure to produce materials with a range of pore sizes. Polymer precursor routes to non-oxide ceramics offer products with superior thermal and chemical stability in many cases. Polymethylsilane (PMS), a versatile cross linked SiC precursor, [(MeHSi){sub x}(MeSi){sub y}], was synthesized using published procedures to yield fluid precursors with a low (20--40%) degree of cross linking. Unique, highly cross linked (60--70%), solid polymers were produced under reaction conditions which carefully conserve the volatile monomer. These two polymers were converted to SiC to determine the relative importance of the various contributions to porosity, and to assess the role of precursor structure on porosity development in non-oxides. Initial results indicate that precursor structure has little effect on porosity. The development of the porosity appears to be dominated by high temperature thermochemistry and/or microstructural changes.

Zeolite films are sought as components of molecular sieve membranes. Different routes used to prepare zeolite composite membranes include growing zeolite layers from gels on porous supports, depositing oriented zeolites on supports, and dispersing zeolites in polymeric membranes. In most cases, it is very difficult to control and avoid the formation of cracks and/or pinholes. The approach to membrane synthesis is based on hydrothermally converting films of layered aluminosilicates into zeolite films. The authors have demonstrated this concept by preparing zeolite A membranes on alumina supports from kaolin films. The authors have optimized the process parameters not only for desired bulk properties, but also for preparing thin (ca. 5 {micro}m), continuous zeolite A films. Scanning electron microscopy shows highly intergrown zeolite A crystals over most of the surface area of the membrane, but gas permeation experiments indicate existence of mesoporous defects and/or intercrystalline gaps. It has been demonstrated that the thickness of the final zeolite A membrane can be controlled by limiting the amount of precursor kaolin present in the membrane.

This project focuses on the modification of silica and alumina surfaces by titania and hydrous titanium oxide ion-exchange films, and the use of these modified materials as supports for MoS{sub 2} catalysts. FTIR studies of molybdena interaction with {gamma}-Al{sub 2}O{sub 3} demonstrate that at low loadings Mo interacts with the most basic hydroxyl groups, and that these hydroxyls are associated with tetrahedrally coordinated Al. Furthermore, hydrodesulfurization (HDS) activity as a function of Mo loading shows a maximum in specific activity with loading. The Mo species bound to tetrahedrally coordinated Al sites are therefore believed to be inactive for the HDS reaction. Only after the tetrahedral Al sites have completely consumed does molybdena adsorb on the alumina in a manner that leads to an active catalyst. According to this scheme, the activity of alumina supported MoS{sub 2} catalysts could be greatly improved by either titrating the tetrahedral Al sites with a modifier, or by using {alpha}-Al{sub 2}O{sub 3} which contains no tetrahedrally coordinated Al. HDS tests over MoS{sub 2} supported on both {alpha}-Al{sub 2}O{sub 3} and {gamma}-Al{sub 2}O{sub 3} modified by a titania film confirm this hypothesis. Neither support material gives rise to a maximum in activity with Mo loading, but rather exhibits a smooth decrease in activity with loading. Furthermore, for equivalent Mo loadings the activity of both of these support materials exceeds that of unmodified {gamma}-Al{sub 2}O{sub 3} due to the fact that no Mo is tied up in the inactive form. FTIR, XPS, and TEM are currently being used to determine whether the model can indeed account for the observed activity trends. Although the surface area of {alpha}-Al{sub 2}O{sub 3} is too low for use as a commercial catalyst, the titania coated {gamma}-Al{sub 2}O{sub 3} represents an important, practical improvement in support materials for hydrotreating catalysts.

The DOE/DOD Environmental Data Bank was established in 1959 as a central location for storing weapons and equipment environments information from a variety of DOE, DOD, and industrial sources and continues to be maintained by Sandia National Laboratories. The Environmental Data Bank contains approximately 2,900 documents regarding normal and abnormal environments that describe the handling, storage, transportation, use, and general phases, which occur during the life of a weapon system. The Environmental Data Bank contains a vast assortment of resources that document crash, fire, and chemical environments resulting from aircraft, rail, ship, and truck accidents, as well as crash and thermal tests conducted on shipping containers. Also included are studies on the hazards of exposure to liquid natural gas fireballs, chemical fireballs, and hydrogen fireballs. This paper describes the DOE/DOD Environmental Data Bank system, its structure, data sources, and usage, with particular emphasis on its use for safety assessments at Sandia National Laboratories.

In this paper the authors identify factors which influence the safety philosophy used in the US commercial/industrial sector and compare them against those factors which influence nuclear weapons safety. Commercial/industrial safety is guided by private and public safety standards. Generally, private safety standards tend to emphasize product reliability issues while public (i.e., government) safety standards tend to emphasize human factors issues. Safety in the nuclear weapons arena is driven by federal requirements and memoranda of understanding (MOUs) between the Departments of Defense and Energy. Safety is achieved through passive design features integrated into the nuclear weapon. Though the common strand between commercial/industrial and nuclear weapons safety is the minimization of risk posed to the general population (i.e., public safety), the authors found that each sector tends to employ a different safety approach to view and resolve high-consequence safety issues.

Over forty safety and security related research and development projects have been initiated between Sandia National Laboratories and the Russian nuclear weapons laboratories VNIIEF and VNIITF. About half of these projects have been completed. All relate to either safety or security methodology development, processes, accident environment analysis and testing, accident databases, assessments or product design of devices. All projects have a potential benefit to various safety or security programs and some may directly have commercial applications. In general, these projects could benefit risk assessments associated with systems that could result in accidents or incidents having high public consequences. These systems typically have already been engineered to have very low assessed probabilities of occurrence of such accidents or incidents. This paper gives an overview of the Sandia surety program with a focus on the potential for future collaboration between Sandia, three Russian Institutes; VNIIEF, VNIITF and VNIIA, and other industry and government organizations. The intent is to serve as an introduction to a roundtable session on Russian Safety Collaboration at the 14th International System Safety Conference. The current Sandia collaboration program scope and rationale is presented along with the evolved program focus. An overview of the projects is given and a few specific projects are briefly highlighted with tangible results to date.

Much work has been devoted to high consequence events with low frequency of occurrence. Characteristic of these events are bridge failure (such as that of the Tacoma Narrows), building failure (such as the collapse of a walkway at a Kansas City hotel), or compromise of a major chemical containment system (such as at Bhopal, India). Such events, although rare, have an extreme personal, societal, and financial impact. An interesting variation is demonstrated by financial losses due to fraud and abuse in the money management system. The impact can be huge, entailing very high aggregate costs, but these are a result of the contribution of many small attacks and not the result of a single (or few) massive events. Public awareness is raised through publicized events such as the junk bond fraud perpetrated by Milikin or gross mismanagement in the failure of the Barings Bank through unsupervised trading activities by Leeson in Singapore. These event,s although seemingly large (financial losses may be on the order of several billion dollars), are but small contributors to the estimated $114 billion loss to all types of financial fraud in 1993. This paper explores the magnitude of financial system losses and identifies new areas for analysis of high consequence events including the potential effect of malevolent intent.

One of the benefits resulting from the collapse of the Soviet Union is the increased dialogue currently taking place between American and Russian nuclear weapons scientists in various technical arenas. One of these arenas currently being investigated involves collaborative studies which illustrate how risk assessment is perceived and utilized in the Former Soviet Union (FSU). The collaborative studies indicate that, while similarities exist with respect to some methodologies, the assumptions and approaches in performing risk assessments were, and still are, somewhat different in the FSU as opposed to that in the US. The purpose of this paper is to highlight the present knowledge of risk assessment methodologies and philosophies within the two largest nuclear weapons laboratories of the Former Soviet Union, Arzamas-16 and Chelyabinsk-70. Furthermore, This paper will address the relative progress of new risk assessment methodologies, such as Fuzzy Logic, within the framework of current risk assessment methods at these two institutes.

Over the past several years, the authors have performed experimental studies focused on understanding small-scale flow processes within discrete fractures and individual matrix blocks; much of the understanding gained in that time differs from that underlying the basic assumptions used in effective media representations. Here they synthesize the process level understanding gained from their laboratory studies to explore how such small-scale processes may influence the behavior of fluid flow in fracture networks and ensembles of matrix blocks at levels sufficient to impact the formulation of intermediate-scale effective media properties. They also explore, by means of a thought experiment, how these same small-scale processes could couple to produce a large-scale system response inconsistent with current conceptual models based on continuum representations of flow through unsaturated, fractured rock. Based on their findings, a number of modifications to existing dual permeability models are suggested that should allow them improved applicability; however, even with these modifications, it is likely that continuum representations of flow through unsaturated fractured rock will have limited validity and must therefore be applied with caution.

The goal of this work is to extend the use of existing path expression theory and methodologies to ensure that critical software event sequences are maintained even in the face of malevolent attacks and harsh or unstable operating environments. This will be accomplished by providing dynamic fault management measures directly to the software developer and to their varied development environments. This paper discusses the perceived problems, a brief overview of path expressions, and the author`s proposed extension areas. The authors discuss how the traditional path expression usage and implementation differs from the intended usage and implementation.

Garnet phosphors have potential for use in field emission displays (FEDs). Green-emitting Gd{sub 3}Ga{sub 5}O{sub 12}:Tb (GGG:Tb) and Y{sub 3}Al{sub 5}O{sub 12}:Tb (YAG:Tb) are possible alternatives to ZnO:Zn, because of their excellent resistance to burn, low-voltage efficiency, (3.5 lm/W from GGG:Tb at 800 V), and saturation resistance at high power densities. Hydrothermal and combustion synthesis techniques were employed to improve the low-voltage efficiency of YAG:Tb, and Y{sub 3}Ga{sub 5}O{sub 12}:Tb (YGG:Tb). Synthetic technique did not affect low-voltage (100--1,000 V) efficiency, but affected the particle size, morphology, and burn resistance. The small particle size phosphors obtained via hydrothermal (<1 {micro}m) and combustion reactions (<1 {micro}m) would benefit projection TV, high-definition TV (HDTV), and heads-up displays (HUDs), where smaller pixel sizes are required for high resolution.

Inductively Coupled Plasma (ICP) sources are extremely promising for large-area, high-ion density etching or deposition processes. In this review the authors compare results for GaAs and GaN etching with both ICP and Electron Cyclotron Resonance (ECR) sources on the same single-wafer platform. The ICP is shown to be capable of very high rates with excellent anisotropy for fabrication of GaAs vias or deep mesas in GaAs or GaN waveguide structures.

Vulnerability analyses for information systems are complicated because the systems are often geographically distributed. Sandia National Laboratories has assembled an interdisciplinary team to explore the applicability of probabilistic logic modeling (PLM) techniques (including vulnerability and vital area analysis) to examine the risks associated with networked information systems. The authors have found that the reliability and failure modes of many network technologies can be effectively assessed using fault trees and other PLM methods. The results of these models are compatible with an expanded set of vital area analysis techniques that can model both physical locations and virtual (logical) locations to identify both categories of vital areas simultaneously. These results can also be used with optimization techniques to direct the analyst toward the most cost-effective security solution.

The in-scattering processes, which reduce the decay of the active medium polarization, should be included in a consistent treatment of semiconductor laser gain. The in-scattering processes affect the laser gain by decreasing the influence of the high k-states, which contribute absorption to the spectrum. A theory, based on the semiconductor-Bloch equations with the effects of carrier-carrier scattering treated at the level of the quantum kinetic equations in the Markov limit, predicts gain spectra that do not exhibit absorption below the renormalized band gap, in agreement with experiment. When compared to gain calculations where the in-scattering contribution is neglected, the theory predicts markedly different properties for intrinsic laser parameters, such as peak gain, gain bandwidth, differential gain and carrier density at transparency, especially at low carrier densities.

Critical software must be safe, secure, and dependable. Traditionally, these have been pursued as separate disciplines. This presentation looks at the traditional approaches and highlights commonalities and differences among them. Each can learn from the history of the others. More importantly, it is imperative to seek a systems approach which blends all three.

Test data on canonical weapon-like fixtures are used to validate previously developed analytical bounding results. The test fixtures were constructed to simulate (but be slightly worse than) weapon ports of entry but have known geometries (and electrical points of contact). The exterior of the test fixtures exhibited exterior resonant enhancement of the incident fields at the ports of entry with magnitudes equal to those of weapon geometries. The interior consisted of loaded transmission lines adjusted to maximize received energy or voltage but incorporating practical weapon geometrical constraints. New analytical results are also presented for bounding the energies associated with multiple bolt joints and for bounding the exterior resonant enhancement of the exciting fields.

Prosperity Games{trademark} are an outgrowth and adaptation of move/countermove and seminar War Games. Prosperity Games{trademark} are simulations that explore complex issues in a variety of areas including economics, politics, sociology, environment, education and research. These issues can be examined from a variety of perspectives ranging from a global, macroeconomic and geopolitical viewpoint down to the details of customer/supplier/market interactions in specific industries. All Prosperity Games{trademark} are unique in that both the game format and the player contributions vary from game to game. This report documents the Biomedical Technology Prosperity Game{trademark} conducted under the sponsorship of Sandia National Laboratories, the Defense Advanced Research Projects Agency, and the Koop Foundation, Inc. Players were drawn from all stakeholders involved in biomedical technologies including patients, hospitals, doctors, insurance companies, legislators, suppliers/manufacturers, regulators, funding organizations, universities/laboratories, and the legal profession. The primary objectives of this game were to: (1) Identify advanced/critical technology issues that affect the cost and quality of health care. (2) Explore the development, patenting, manufacturing and licensing of needed technologies that would decrease costs while maintaining or improving quality. (3) Identify policy and regulatory changes that would reduce costs and improve quality and timeliness of health care delivery. (4) Identify and apply existing resources and facilities to develop and implement improved technologies and policies. (5) Begin to develop Biomedical Technology Roadmaps for industry and government cooperation. The deliberations and recommendations of these players provided valuable insights as to the views of this diverse group of decision makers concerning biomedical issues. Significant progress was made in the roadmapping of key areas in the biomedical technology field.

The behavior of chemical species adsorbed on solid surfaces and exchanged into clay interlayers plays a significant role in controlling many natural and technologically important processes, including rheological behavior, catalysis, plant growth, transport in natural pore fluids and those near anthropogenic hazardous waste sites, and water-mineral interaction. Adsorption and exchange reactions have been the focus of intense study for many decades. Only more recently, however, have there been extensive spectroscopic studies of surface species. Among the spectroscopic methods useful for studying surface and exchanged species (e.g., infrared, X-ray photoelectron spectroscopy [XPS] and X-ray absorption spectroscopy [XAS]), nuclear magnetic resonance spectroscopy (NMR) has the considerable advantage of providing not only structural information via the chemical shift and quadrupole coupling constant but dynamical information in the Hz-mHz range via lineshape analysis and relaxation rate measurements. It is also possible to obtain data in the presence of a separate fluid phase, which is essential for many applications. This paper illustrates the range of applications of NMR methods to surface and exchanged species through review of recent work from our laboratory on Cs in clay interlayers and Cs, Na and phosphate adsorbed on oxide surfaces. The substrate materials used for these experiments and our long-term objectives are related to problems of geochemical interest, but the principals and techniques are of fundamental interest and applicable to a wide range of technological problems.

The software construction process consists of a mixture of informal and formal steps. By their very nature, informal steps cannot be formally verified. Empirical evidence suggests that a majority of software errors originate in the informal steps of the software development process. For this reason, when constructing high assurance software, it is essential that a significant effort be made to increase one`s confidence (i.e., to validate) that the informal steps have been made correctly. Visualization and animation can be used to provide an `intuitive proof` that the informal steps in the software construction process are correct. In addition, the formal portion of software construction often permits/demands artistic (informal) decisions to be made (e.g., design decisions). Such decisions often have unexpected/unforeseen consequences that are only discovered later in the development process. Visualization and animation techniques can be brought to bear on this aspect of the software construction process by providing a better intuitive understanding of the impact of the informal decisions that are made in program development. This increases the likelihood that undesirable decisions can be avoided or at least detected earlier in the development process.

US DOE national laboratories and Russian institutes are becoming increasingly cooperative in support of nonproliferation of nuclear materials. This paper describes completed projects, current work, and areas of possible future cooperation between US laboratories and a Russian Ministry of Atomic Energy (MINATOM) entity, Special Scientific and Production State Enterprise (SNPO). The Kurchatov Institute, SNPO, and the US national laboratories jointly completed a physical protection system (PPS) for a facility housing two reactors at Kurchatov Institute within a very short time frame in 1994. Spin- off projects from this work resulted in a US-witnessed acceptance test of the new system adhering to a procedure adopted in Russia, and visits by DOE laboratories` personnel to SNPO`s sensor development and test facilities at Dubna and Penza. SNPO was one of the MINATOM sites at which Lawrence Livermore National Laboratory and Sandia National Laboratories (SNL) conducted a vulnerability assessment training course. Current cooperative projects include additional physical protection upgrades at Kurchatov where SNPO is involved as an installer and supplier of sensors, alarm display, video, and fiber optic equipment. Two additional contracts between SNL and SNPO result in information on Russian sensor performance and cost and an exchange of US and Russian sensors. Russian sensors will be tested in the United States,a nd US sensors will be tested in Russia. Pacific Northwest Laboratory administers a contract to document the process of certifying physical protection equipment for use at MINATOM facilities. Recent interest in transportation security has opened a new area of cooperation between the national laboratories and SNPO. Future projects are expected to include SNPO participation in physical protection upgrades at other locations in Russia, pedestrian and vehicle portal development, positive personnel identifier testing, and the exchange and testing of additional equipment.

Soil vapor surveys were performed to characterize the approximate location of soil contaminants at a hazardous waste site. The samplers were from two separate companies and a comparison was made between the results of the two techniques. These results will be used to design further investigations at the site.

Material which is not in direct contact with detonating explosives may still be driven by the explosion through impact by driven material or by attachment to driven material. In such circumstances the assumption of inelastic collision permits estimation of the final velocity of an assemblage. Examples of the utility of this assumption are demonstrated through use of Gurney equations. The inelastic collision calculation may also be used for metal parts which are driven by explosives partially covering the metal. We offer a new discounting angle to account for side energy losses from laterally unconfined explosive charges in cases where the detonation wave travels parallel to the surface which is driven.

This report summarizes the results of the Precision Guided Parachute LDRD, a two year program at Sandia National Laboratories which developed a Global Positioning System (GPS) guided parachute capable of autonomous flight and landings. A detailed computer model of a gliding parachute was developed for software only simulations. A hardware in-the-loop simulator was developed and used for flight package system integration and design validation. Initial parachute drop tests were conducted at Sandia`s Coyote Canyon Cable Facility, followed by a series of airdrops using Ross Aircraft`s Twin Otter at the Burris Ranch Drop Zone. Final flights demonstrated in-flight wind estimation and the capability to fly a commanded heading. In the past, the cost and logistical complexity of an initial navigation system ruled out actively guiding a parachute. The advent of the low-cost, light-weight Global Positioning System (GPS) has eliminated this barrier. By using GPS position and velocity measurements, a guided parachute can autonomously steer itself to a targeted point on the ground through the use of control drums attached to the control lanyards of the parachute. By actively correcting for drop point errors and wind drift, the guidance accuracy of this system should be on the order of GPS position errors. This would be a significant improvement over unguided airdrops which may have errors of a mile or more.

This LDRD (Laboratory Directed Research and Development) project was funded for two years beginning in October 1992 (FY93) and was designed as a multidisciplinary approach to determining the structural and physical properties of C{sub 60} intercalated with various gases. The purpose of the study was to evaluate the relative permeation and diffusion of various gases with an ultimate goal of finding an effective filter for gas separations. A variety of probes including NMR, X-ray and neutron diffraction; IR spectroscopy, thermogravimetric analysis and mass spectroscopy were employed on C{sub 60} impregnated with a number of gases including O{sub 2}, N{sub 2}, Ar, Ne, H{sub 2}, NO and CH{sub 4}. In order to increase the absorption and decrease the effective time constraints for bulk samples, these gases were intercalated into the C{sub 60} using pressures to several kbar. The results of these measurements which were quite encouraging for separation of O{sub 2} and N{sub 2} and for H{sub 2} from N{sub 2} led to 17 manuscripts which have been published in peer reviewed journals. The abstracts of these manuscripts are shown below along with a complete citation to the full text.

Simplified formulae are developed for estimating the aerosol decontamination that can be achieved by natural processes in the containments of pressurized water reactors and in the drywells of boiling water reactors under severe accident conditions. These simplified formulae were derived by correlation of results of Monte Carlo uncertainty analyses of detailed models of aerosol behavior under accident conditions. Monte Carlo uncertainty analyses of decontamination by natural aerosol processes are reported for 1,000, 2,000, 3,000, and 4,000 MW(th) pressurized water reactors and for 1,500, 2,500, and 3,500 MW(th) boiling water reactors. Uncertainty distributions for the decontamination factors and decontamination coefficients as functions of time were developed in the Monte Carlo analyses by considering uncertainties in aerosol processes, material properties, reactor geometry and severe accident progression. Phenomenological uncertainties examined in this work included uncertainties in aerosol coagulation by gravitational collision, Brownian diffusion, turbulent diffusion and turbulent inertia. Uncertainties in aerosol deposition by gravitational settling, thermophoresis, diffusiophoresis, and turbulent diffusion were examined. Electrostatic charging of aerosol particles in severe accidents is discussed. Such charging could affect both the coagulation and deposition of aerosol particles. Electrostatic effects are not considered in most available models of aerosol behavior during severe accidents and cause uncertainties in predicted natural decontamination processes that could not be taken in to account in this work. Median (50%), 90 and 10% values of the uncertainty distributions for effective decontamination coefficients were correlated with time and reactor thermal power. These correlations constitute a simplified model that can be used to estimate the decontamination by natural aerosol processes at 3 levels of conservatism. Applications of the model are described.

We report results in three areas of research relevant to the fabrication of monolithic multi-junction photovoltaic devices. (1) The use of compliant intervening layers grown between highly mismatched materials, GaAs and GaP (same lattice constant as Si), is shown to increase the structural quality of the GaAs overgrowth. (2) The use of digital alloys applied to the MBE growth of GaAs{sub x}Sb{sub l-x} (a candidate material for a two junction solar cell) provides increased control of the alloy composition without degrading the optical properties. (3) A nitrogen plasma discharge is shown to be an excellent p-type doping source for CdTe and ZnTe, both of which are candidate materials for a two junction solar cell.

Stirling-cycle engines have been identified as a promising technology for the conversion of concentrated solar energy into usable electrical power. A 25kW electric system takes advantage of existing Stirling-cycle engines and existing parabolic concentrator designs. In previous work, the concentrated sunlight impinged directly on the heater head tubes of the Stirling Thermal Motors (STM) 4-120 engine. A Sandia-designed felt-metal-wick heat pipe receiver was fitted to the STM 4-120 engine for on-sun testing on Sandia`s Test Bed Solar Concentrator. The heat pipe uses sodium metal as an intermediate two-phase heat transfer fluid. The receiver replaces the directly-illuminated heater head previously tested. The heat pipe receiver provides heat isothermally to the engine, and the heater head tube length is reduced, both resulting in improved engine performance. The receiver also has less thermal losses than the tube receiver. The heat pipe receiver design is based on Sandia`s second-generation felt-wick heat pipe receiver. This paper presents the interface design, and compares the heat pipe/engine test results to those of the directly-illuminated receiver/engine package.

Sol-gel polymerication of {alpha}, {omega}-bis(triethoxysilyl)alkanes normally leads to alkylene-bridged polysilsesquioxanes in the form of insoluble, highly crosslinked polymeric gels. Hydrolysis of the six ethoxide groups on each monomer gives silanols that then condense to form a network of siloxane bonds. Unlike most Sol-gel precursors, these flexible hydrocarbon-bridged monomers can participate not only in intermolecular condensation reactions that lead to polymeric networks, but in intramolecular condensation reactions leading to cyclic disilsesquioxanes as well. Partitioning between these two reaction manifolds should be an important determinant of the manner in which the network polymer is assembled and, be an important determinant of the manner in which the network polymer is assembled and, ultimately, the final morphologies of the crosslinked gels. The relative importance of the two pathways should be dependent on a variety of factors, including the reaction mechanism (acid or base catalysis), the concentration of {alpha}, {omega}(triethoxysilyl)alkane and, most importantly for this study, the length of the alkylene bridging group.

The purpose of this research is to characterize existing 2 MeV, 4 MeV and 6 MeV buildup caps, and to determine if a buildup cap can be made for the 0.6 cm{sup 3} thimble ionization chamber that will accurately measure exposures in a high-energy photon radiation field. Two different radiation transport codes were used to computationally characterize existing 2 MeV, 4 MeV, and 6 MeV buildup caps for a 0.6 cm{sup 3} active volume thimble ionization chamber: ITS, The Integrated TIGER Series of Coupled Electron-Photon Monte Carlo Transport Codes; and CEPXS/ONEDANT, A One-Dimensional Coupled Electron-Photon Discrete Ordinates Code Package. These codes were also used to determine the design characteristics of a buildup cap for use in the 18 MeV photon beam produced by the 14 TW pulsed power HERMES-III electron accelerator. The maximum range of the secondary electron, the depth at which maximum dose occurs, and the point where dose and collision kerma are equal have been determined to establish the validity of electronic equilibrium. The ionization chamber with the appropriate buildup cap was then subjected to a 4 MeV and a 6 MeV bremmstrahlung radiation spectrum to determine the detector response.

When software is used in safety-critical, security-critical, or mission-critical situations, it is imperative to understand and manage the risks involved. A risk assessment methodology and toolset have been developed which are specific to software systems and address a broad range of risks including security, safety, and correct operation. A unique aspect of this methodology is the use of a modeling technique that captures interactions and tradeoffs among risk mitigators. This paper describes the concepts and components of the methodology and presents its application to example systems.

A particular out-of-specification mechanical dimension on Type-N(f) [Type-N(female)] microwave connectors sometimes disqualifies otherwise perfectly acceptable microwave devices from being used in calibration systems. The Miniature Machining Group at Sandia National Laboratories applied a technique called Electrical Discharge Machining (EDM) to quickly and economically machine these devices without disassembly. In so doing, they facilitated the use of existing components without the need to purchase new devices. The technique also improves an uncertainty of calibration known as Mismatch Uncertainty by optimizing the reflection coefficient of the calibration test port. This effects a reduction in overall calibration uncertainties.

This report provides a baseline update to provide the background information necessary for personnel to prepare clear and consise NEPA documentation. The environment of the Sandia National Laboratories is described in this document, including the ecology, meteorology, climatology, seismology, emissions, cultural resources and land use, visual resources, noise pollution, transportation, and socioeconomics.

The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface- based and underground testing. Analyses have been performed to support the design of an Exploratory Studies Facility (ESF) and the design of the tests performed as part of the characterization process, in order to ascertain that they have minimal impact on the natural ability of the site to isolate waste. The information in this report pertains to sensitivity studies evaluating previous hydrological performance assessment analyses to variation in the material properties, conceptual models, and ventilation models, and the implications of this sensitivity on previous recommendations supporting ESF design. This document contains information that has been used in preparing recommendations for Appendix I of the Exploratory Studies Facility Design Requirements document.

A team has developed an improved resolution ultrasound system for low cost diagnostics. This paper describes the development of an ultrasound based imaging system capable of generating 3D images showing surface and subsurface tissue and bone structures. We include results of a comparative study between images obtained from X-Ray Computed Tomography (CT) and ultrasound. We found that the quality of ultrasound images compares favorably with those from CT. Volumetric and surface data extracted from these images were within 7% of the range between ultrasound and CT scans. We also include images of porcine abdominal scans from two different sets of animal trials.

Sandia National Laboratories (SNL) and Underwriters Laboratories, Inc., (UL) have jointly established the Security Equipment and Systems Certification Program (SESCP). The goal of this program is to enhance industrial and national security by providing a nationally recognized method for making informed selection and use decisions when buying security equipment and systems. The SESCP will provide a coordinated structure for private and governmental security standardization review. Members will participate in meetings to identify security problems, develop ad-hoc subcommittees (as needed) to address these identified problems, and to maintain a communications network that encourages a meaningful exchange of ideas. This program will enhance national security by providing improved security equipment and security systems based on consistent, reliable standards and certification programs.

After 5 y storage at Allied Signal, a subassembly with SA1388-1 diodes failed testing and the cause was an unacceptable current leak rate in one of the diodes. This was traced to a CuS deposit in a single production lot of diodes; however only about 0.3% failed the specification. A study was performed to determine the cause and potential long-term significance of this problem. Probable cause was determined to be the P-bearing braze material not being compatible with the Ag immersion plating solution (cyanide-based) and to the storage environment containing sulfur.

Solid free form fabrication is a fast growing automated manufacturing technology that has reduced the time between initial concept and fabrication. Starting with CAD renditions of new components, techniques such as stereolithography and selective laser sintering are being used to fabricate highly accurate complex 3-D objects using polymers. Together with investment casting, sacrificial polymeric objects are used to minimize cost and time to fabricate tooling used to make complex metal casting. This paper describes recent developments in LENS{trademark} (Laser Engineered Net Shaping) to fabricate the metal components {ital directly} from CAD solid models and thus further reduce the lead time. Like stereolithography or selective sintering, LENS builds metal parts line by line and layer by layer. Metal particles are injected into a laser beam where they are melted and deposited onto a substrate as a miniature weld pool. The trace of the laser beam on the substrate is driven by the definition of CAD models until the desired net-shaped densified metal component is produced.

Three years ago, production requirements for a T73-tempered aluminium 7075 (Al 7075-T73) component were curtailed and the ``in-process`` parts were stored. During recent attempts to complete processing, visible defects were discovered in this component. Defects at such an early stage in the 20+ year lifetime of the component pose reliability concerns. Chemical and microstructural analysis, mechanical testing, and corrosion evaluation were performed to determine the impact of the defects on material properties.

Sandia is developing PBFA-Z, a 20-MA driver for z-pinch experiments by replacing the water lines, insulator stack, and MITLs on PBFA II with new hardware. The design of the vacuum insulator stack was dictated by the drive voltage, the electric field stress and grading requirements, the water line and MITL interface requirements, and the machine operations and maintenance requirements. The insulator stack will consist of four separate modules, each of a different design because of different voltage drive and hardware interface requirements. The shape of the components in each module, i.e., grading rings, insulator rings, flux excluders, anode and cathode conductors, and the design of the water line and MITL interfaces, were optimized by using the electrostatic analysis codes, ELECTRO and JASON. The time dependent performance of the insulator stack was evaluated using IVORY, a 2-D PIC code. This paper will describe the insulator stack design and present the results of the ELECTRO and IVORY analyses.

The group III-nitrides continue to generate interest due to their wide band gaps and high dielectric constants. These materials have made significant impact on the compound semiconductor community as blue and ultraviolet light emitting diodes (LEDs). Realization of more advanced devices; including lasers and high temperature electronics, requires dry etch processes which are well controlled, smooth, highly anisotropic and have etch rates exceeding 0.5 {mu}m/min. In this paper, we compare electron cyclotron resonance (ECR), inductively coupled plasma (ICP), and reactive ion etch (RIE) etch results for GaN. These are the first ICP etch results reported for GaN. We also report ECR etch rates for GaN as a function of growth technique.

We have been investigating the applicability of fuzzy mathematics in safety assessments (PSAs). It is a very efficient approach, both in terms of methodology development time and program execution time. Most importantly, it processes subjective information subjectively, not as if it were based on measured data. One of the most useful results of this work is that we have shown the potential for significant differences (especially in perceived margin relative to a decision threshold) between fuzzy mathematics analysis and conventional PSA analysis. This difference is due to subtle factors inherent in the choice of probability distributions for modeling uncertainty. Since subjective uncertainty, stochastic variability, and dependence are all parts of most practical situations, a technique has been developed for combining the three effects. The methodology is based on hybrid numbers and on Frechet inequality dependency bounds analysis. Some new results have also been obtained in the areas of efficient disjoint set representations and constrained uncertainty and variability analysis.

We have found that nanosecond optical parametric oscillators pumped well above threshold by single longitudinal mode pulse produce signal and idler light that is nearly purely phase modulated, even for unseeded operation.

There is a need for an automated system for protecting and monitoring sensitive or classified parts and material. Sandia has developed a real-time personnel and material tracking system (PAMTRAK) that has been installed at selected DOE facilities. It safeguards sensitive parts and material by tracking tags worn by personnel and by monitoring sensors attached to the parts or material. It includes remote control and alarm display capabilities and a complementary program in Keyhole to display measured material attributes remotely. This paper describes the design goals, the system components, current installations, and the benefits a site can expect when using PAMTRAK.

Expert system implementation can take numerous forms ranging form traditional declarative rule-based systems with if-then syntax to imperative programming languages that capture expertise in procedural code. The artificial intelligence community generally thinks of expert systems as rules or rule-bases and an inference engine to process the knowledge. The welding advisor developed at Sandia National Laboratories and described in this paper deviates from this by codifying expertise using object representation and methods. Objects allow computer scientists to model the world as humans perceive it giving us a very natural way to encode expert knowledge. The design of the welding advisor, which generates and evaluates solutions, will be compared and contrasted to a traditional rule- based system.

Traditional definitions of risk partition concern into the probability of occurrence and the consequence of the event. Most safety analyses focus on probabilistic assessment of an occurrence and the amount of some measurable result of the event, but the real meaning of the ``consequence`` partition is usually afforded less attention. In particular, acceptable social consequence (consequence accepted by the public) frequently differs significantly from the metrics commonly proposed by risk analysts. This paper addresses some of the important system development issues associated with consequences, focusing on ``high consequence operations safety.``

Field ion microscopy show a strong correlation between mobility and shape of small clusters on fcc(100) metal surfaces. For self-diffusion on Rh(100) this correlation lead to an oscillatory behavior in the activation energy of surface diffusion as a function of cluster size. Comparison of measured activation energies to theory indicate that the mechanism of cluster diffusion involves individual displacements of edge atoms (ie, perimeter diffusion). Rate-determining step in migration of clusters is partial detachment of one of the perimeter atoms. Relative ease of adatom motion along straight edges of stationary clusters also permits measurements of diffusion barriers at steps, which can be useful in interpretation of fractal vs compact island growth on fcc metal surfaces.

GaAs-based Metal Semiconductor Field Effect transistors (MESFETs) and High Electron Mobility Transistors (HEMTs) have been the focus of research for high-temperature operation due to the 1.42 eV band gap of GaAs that reduces thermal carrier generation as compared to 1.1 eV silicon-based electronics. Although schemes have been proposed to minimize substrate currents at elevated temperatures, high-temperature operation of these devices is ultimately limited by the gate leakage current of the Schottky gate contact. Since a Junction Field Effect Transistor (JFET) has a higher gate barrier to current flow than a Schottky barrier MESFET as a result of the p/n junction gate, JFETs should have superior performance at elevated temperatures. This paper compares the high-temperature performance of a self-aligned GaAs MESFET and JFET. Both devices suffer from substrate leakage at high temperature; however, the JFET has superior gate characteristics and maintains a larger fraction of its room temperature transconductance at 300 C.

We have studied the chemical selectivity and sensitivity of surface acoustic wave (SAW) sensors covered by (COO{sup {minus}}){sub 2}/Cu{sup 2+}-terminated interfaces by examining the response of self-assembled monolayer (SAM) films formed from the solution phase for 36, 84, and 180 h adsorption times. These organomercaptan SAMs were prepared on thin-film Au surfaces having variable, controlled grain size. The SAW response from the carboxylate coordinated Cu{sup 2+}-terminated SAM is compared to that from methyl-terminated SAM, as these films interact with a vapor-phase organophosphonate analyte and the vapors of common organic solvents. Results have implications for designing and reliably fabricating chemical sensors that respond to specific organic analytes.

Ion implantation doping and isolation has played a critical role in realizing high performance photonic and electronic devices in all mature semiconductor materials; this is also expected for binary III-Nitride materials (InN, GaN, AlN) and their alloys as epitaxy improves and more advanced device structures fabricated. This paper reports on recent progress in ion implantation doping of III-Nitride materials that has led to the first demonstration of a GaN JFET (junction field effect transistor). The JFET was fabricated with all ion implantation doping; in particular, p-type doping of GaN with Ca has been demonstrated with an estimated acceptor ionization energy of 169 meV. O-implantation has also been studied and shown to yield n-type conduction with an ionization energy of {similar_to}29 meV. Neither Ca or O display measurable redistribution during a 1125 C, 15 s activation anneal which sets an upper limit on their diffusivity at this temperature of 2.7{times}10{sup {minus}13}cm{sup 2}/s.

Asynchronous Transfer Mode (ATM) is a new data communications technology that promises to integrate voice, video, and data traffic into a common network infrastructure. In order to fully utilize ATM`s ability to transfer real-time data at high rates, applications will start to access the ATM layer directly. As a result of this trend, security mechanisms at the ATM layer will be required. A number of research programs are currently in progress which seek to better understand the unique issues associated with ATM security. This paper describes some of these issues, and the approaches taken by various organizations in the design of ATM layer security mechanisms. Efforts within the ATM Forum to address the user communities need for ATM security are also described.

We present a manipulator placement algorithm for minimizing the length of the manipulator motion performing a visit-point task such as spot welding. Given a set of points for the tool of a manipulator to visit, our algorithm finds the shortest robot motion required to visit the points from each possible base configuration. The base configurations resulting in the shortest motion is selected as the optimal robot placement. The shortest robot motion required for visiting multiple points from a given base configuration is computed using a variant of the traveling salesman algorithm in the robot joint space and a point-to-point path planner that plans collision free robot paths between two configurations. Our robot placement algorithm is expected to reduce the robot cycle time during visit- point tasks, as well as speeding up the robot set-up process when building a manufacturing line.

In recent years, much of the progress in Computer-Aided Manufacturing has emphasized the use of simulation, finite-element analysis, and other science-based techniques to plan and evaluate manufacturing processes. These approaches are all based on the idea that we can build sufficiently faithful models of complex manufacturing processes such as machining, welding, and casting. Although there has been considerable progress in this area, it continues to suffer from difficulties: the first of these is that the kind of highly accurate models that this approach requires may take many person months to construct, and the second is the large amount of computing resources needed to run these simulations. Two design advisors, Near Net-Shape Advisor and Design for Machinability Advisor, are being developed to explore the role of heuristic, knowledge-based systems for manufacturing processes, both as an alternative to more analytical techniques, and also in support of these techniques. Currently the advisors are both in the prototype stage. All indications lead to the conclusion that the advisors will be successful and lay the groundwork for additional systems such as these in the future.

Lithium wall conditioning has been used in a recent campaign evaluating high performance negative central shear (NCS) discharges. During this campaign, the highest values of stored energy (4.4 MJ), neutron rate (2.4 x 10{sup 16}/s), and nT{sub i}{tau} (7 x 10{sup 20} m{sup -3}-keV-s) achieved to date in DIII-D were obtained. High performance NCS discharges were achieved prior to beginning lithium conditioning, but it is clear that shot reproducibility and performance were improved by lithium conditioning. Central and edge oxygen concentrations were reduced after lithium conditioning, Lithium conditioning, consisting of up to four pellets injected at the end of the preceding discharge, allowed the duration of the usual inter-shot helium glow discharge to be reduced and reproducible high auxiliary power discharges, P{sub NBI} {<=} 22 MW, were obtained with plasma currents up to 2.4 MA.

From the beginnings of the U.S. nuclear weapons program, military and civilian dual- agency judgment has been fundamental to achieving nuclear weapon and weapon system safety. This interaction was initiated by the Atomic Energy Act of 1946, which created the Atomic Energy Commission (AEC). The principle of using dual-agency judgment has been perpetuated in the design and assessment of the weapon and weapon system acceptance process since that time. This fundamental approach is still used today in all phases of the weapon life. In this paper, an overview of the history and philosophy of the approach is described.

We have synthesized monolithic particulate gels of periodic mesoporous silica by adding tetramethoxysilane to a homogeneous alkaline micellar precursor solution. The gels exhibit 5 characteristic length scales over 4 orders of magnitude: fractal domains larger than the particle size (>500 nm), particles that are {approximately}150 to 500 nm in diameter, interparticle pores that are on the order of the particle size, a feature in the gas adsorption measurements that indicates pores {approximately}10-50 nm, and periodic hexagonal arrays of {approximately}3 nm channels within each particle. The wet gel monoliths exhibit calculated densities as low as {approximately}0.02 g/cc; the dried and calcined gels have bulk densities that range from {approximately}0.3-0.5 g/cc. The materials possess large interparticle ({approximately}1.0-2.3 cc/g) and intraparticle ({approximately}0.6 cc/g) porosities.

This paper reviews several coupled theoretical and experimental investigations of the effect of microstructure on momentum transport in concentrated suspensions. An expression to predict the apparent suspension viscosity of mixtures of rods and spheres is developed and verified with falling-ball viscometry experiments. The effects of suspension-scale slip (relative to the bulk continuum) are studied with a sensitive spinning-ball rheometer, and the results are explained with a novel theoretical method. The first noninvasive, nuclear magnetic resonance imaging measurements of the evolution of velocity and concentration profiles in pressure-driven entrance flows of initially well mixed suspensions in a circular conduit are described, as well as more complex two-dimensional flows with recirculation, e.g. flow in a journal bearing. These data in nonhomogeneous flows and complementary three-dimensional video imaging of individual tracer particles in homogeneous flows are providing much needed information on the effects of flow on particle interactions and effective theological properties at the macroscale.

Four of the better developed resist schemes that are outgrowths of DUV (248 and 193 nm) resist development are considered as candidates for EUV. They are as follows: trilayer, a thin imaging layer on top of a refractor masking/pattern transfer layer on top of a planarizing and processing layer (PPL); solution developed, organometallic bilayer where the imaging and masking layer have been combined into one material on top of a PPL; and finally silylated resists. They are examined in a very general form without regard to the specifics of chemistry of the variations within each group, but rather to what is common to each group and how that affects their effectiveness as candidates for a near term EUV resist. In particular they are examined with respect to sensitivity, potential resolution, optical density, etching selectivity during pattern transfer, and any issues associated with pattern fidelity such as swelling.

We have deposited ZrO{sub 2}, TiO{sub 2}, and SnO{sub 2} films on ST-cut quartz surface acoustic wave (SAW) devices via sol-gel techniques. The films range from 100 to 300 nm thick and have porosities after calcination at 300{degrees}C that range from 82-88 % for ZrO{sub 2}, 77-81% for TiO{sub 2}, and 57-66% for SnO{sub 2}. In all cases, we have varied the synthesis and processing parameters over a wide range to optimize film properties: metal ion concentration (0.05-1.0 M), the H{sub 2}O:metal ratio (0.3-5.3), the acid concentration in the sol (0.02-0.7 M), the modifier ligand:metal ratio (r = 0.0-1.0), the processing conditions (100-900{degrees}C). The modifier ligand, triethanolamine (TEA), is added to each solution to allow multilayer films to be made crack free. The multilayer films are studied by optical microscopy, ellipsometry, X-ray diffraction, and N{sub 2} sorption. Preliminary high temperature frequency response measurements to target gases, such as, H{sub 2}, NO, NO{sub 2}, and propylene indicate limited sensitivity for the configurations tested.

The hydrolysis and self- and cross-condensation kinetics of the hybrid sol tetraethoxysilane and ethyltriethoxysilane were investigated by high resolution {sup 29}Si NMR spectroscopy. A kinetic model in which hydrolysis is reversible and condensation is irreversible was developed. The authors found excellent agreement between the product distributions measured by {sup 29}Si NMR spectroscopy and calculated by the model. The cross-condensation rates for each of the sols were intermediate to the condensation rates of the individual components. Calculations show that for these sols, the concentration of cross-condensed species is a weak function of the relative rates of self-condensation.

The Sr-Bi-Ta-O system is of interest for thin-film non-volatile ferroelectric memories. A better understanding of the process by which the perovskite phase forms can provide insight for improved processing of this ferroelectric compound. The authors have prepared thin-films by a chemical method using Sr-acetate, Bi-acetate and Ta-ethoxide; cation ratios were {approximately} 1:2:2 for Sr, Bi, and Ta, respectively. Results of in-situ crystallization studies using High-Temperature Grazing-Incidence X-ray Diffraction (HTGIXRD) have demonstrated that a fluorite structure, forming in the {approximately}600--700 C range, acts as an intermediate phase prior to the crystallization of the perovskite. Additional samples with cation ratios of {approximately} 1:0.8:2 were also investigated. Results for samples prepared with the 0.8 Bi content indicated that a pyrochlor phase forms which contains a substantial deficiency in Bi compared to the composition of the perovskite phase. The structures of the pyrochlore and fluorite phases and their relation to the formation of the perovskite ferroelectric are discussed.

Silicon nitride powders with an average size as low as 7 nm are synthesized in a pulsed radio frequency glow discharge. The as-synthesized silicon nitride powder from a silane/ammonia plasma has a high hydrogen content and is sensitive to oxidation in air. Post-plasma heating of the powder in a vacuum results in nitrogen loss, giving silicon-rich powder. In contrast, heat treatment at 800 C for 20 minutes in an ammonia atmosphere (200 Torr pressure) yields a hydrogen-free powder which is stable with respect to atmospheric oxidation. Several approaches to synthesizing silicon carbide nano-size powders are presented. Experiments using silane/hydrocarbon plasmas produce particles with a high hydrogen content as demonstrated by Fourier transform infrared analysis. The hydrogen is present as both CH and SiH functionality. These powders are extremely air-sensitive. A second approach uses a gas mixture of methyltrichlorosilane and hydrogen. The particles have a low hydrogen content and resist oxidation. Particle morphology of the silicon carbide is more spherical and there is less agglomeration than is observed in the silicon nitride powder.

Development of capillary stress in porous xerogels, although ubiquitous, has not been systematically studied. The authors have used the beam bending technique to measure stress isotherms of microporous thin films prepared by a sol-gel route. The thin films were prepared on deformable silicon substrates which were then placed in a vacuum system. The automated measurement was carried out by monitoring the deflection of a laser reflected off the substrate while changing the overlying relative pressure of various solvents. The magnitude of the macroscopic bending stress was found to reach a value of 180 MPa at a relative pressure of methanol, P/Po = 0.001. The observed stress is determined by the pore size distribution and is an order of magnitude smaller in mesoporous thin films. Density Functional Theory (DFT) indicates that for the microporous materials, the stress at saturation is compressive and drops as the relative pressure is reduced.

Using infrared light scattering microscopy, the authors have directly observed the inhibition of photon propagation in a 2-dimensional photonic lattice fabricated as a hexagonal array of AlGaAs posts. The lattice was formed by reactive ion etching of {approximately}400 nm diameter posts defined by electron beam lithography. The lattice design parameters correspond to a photonic bandgap near 1.5 {micro}m as calculated by Meade et al. This hexagonal array of posts is an improvement over early honeycomb lattices because it is easier to fabricate. The photonic lattice of 1.4 {micro}m high posts was incorporated into waveguide designed for single mode at 1.5 {micro}m. Several waveguide/lattice combinations were fabricated, including M-bar and K-bar lattice orientations aligned parallel to the waveguide and different numbers of lattice periods. The waveguide/lattice structures were fabricated on GaAs substrates that were subsequently thinned and cleaved to couple light into the waveguide facets. Using a specially designed triple infrared microscope system, they simultaneously imaged the input and output facets and the top surface of the waveguide as laser light was focused onto the input facet. Because of internal scattering in the waveguide, light is scattered upward outward and can be imaged with an infrared camera. Images for reflected input, waveguide scattered light, and transmitted output light for the waveguide with (left images) and without the photonic lattice (right images) are shown. The lefthand image shows how the lattice interrupts the transport of light through the waveguide.

The purpose of this contribution is to propose an ``Authentication Information Element`` that can be used to carry authentication information within the ATM signaling protocols. This information may be used by either signaling entity to validate the claimed identity of the other, and to verify the integrity of a portion of a message`s contents. By specifying a generic authentication IE, authentication information can be generated by any signature algorithm, and can be appended to any ATM signaling message. Procedures for the use of this information element are also provided.

Software process improvement has become a popular pastime, for a variety of reasons. The Software Engineering Institute`s summary of experimental data, which resulted in the Capability Maturity Model, has now had considerable corroboration. There are nearly as many software processes as there are combinations of developers, users, and products. Similarly, there are probably as many software process improvement approaches. However, the meta-process for performing process improvement is quite straightforward. Processes can be represented by a small number of abstractions, with variety supplied through implementation details. The scheme for improvement is almost self-evident: figure out where you are now, use a software process maturity guide to identify shortcomings, plot a change in a direction to eliminate a shortcoming, and go for it. This paper won`t dwell on the meta process and its enactment; the authors simply assume one is in place. Rather, they consider some ways to improve the testing aspects of your software process. These may be changes in what you do for testing as well as in how you do it.

GaN is an attractive material for use in high-temperature or high-power electronic devices due to its high bandgap (3.39 eV), high breakdown field ({approximately}5 {times} 10{sup 6} V/cm), high saturation drift velocity (2.7 {times} 10{sup 7} cm/s), and chemical inertness. To this end, Metal Semiconductor FETs (MESFETs), High Electron Mobility Transistors (HEMTs), Heterostructure FETs (HFETs), and Metal Insulator Semiconductor FETs (MISFETs) have all been reported based on epitaxial AlN/GaN structures (Khan 1993a,b; Binari 1994 and 1995). GaN Junction Field Effect Transistors (JFETs), however, had not been reported until recently (Zolper 1996b). JFETs are attractive for high-temperature operation due to the inherently higher thermal stability of the p/n junction gate of a JFET as compared to the Schottky barrier gate of a MESFET or HFET. In this paper the authors present the first results for elevated temperature performance of a GaN JFET. Although the forward gate properties are well behaved at higher temperatures, the reverse characteristics show increased leakage at elevated temperature. However, the increased date leakage alone does not explain the observed increase in drain current with temperature. Therefore, they believe this first device is limited by temperature activated substrate conduction.

Structure and properties of a series of modified polydimethylsiloxane (PDMS) elastomers reinforced by {ital in situ} generated silic particles were investigated. The PDMS elastomer was modified by systematically varying the molecular weight between reactive groups incorporated into the backbone. Tetraethoxysilane (TEOS) and partial hydrolyzate of TEOS were used to generate silic particles. Chemistry and phase structure of the materials were investigated by {sup 29}Si magic angle spinning nuclear magnetic resonance spectroscopy and swelling experiments.

Conventional III-V metallizations chemes such as Au/Ge/Ni, Ti/Pt/Au, and Au/Be were found to display poor thermal stability on both GaN and InGaN, with extensive reaction and contact degradation at {le}500 C. By contrast, W was found to produce low contact resistance ({rho}{sub c}{similar_to}8x10{sup -5}{Omega}cm{sup 2}) to n-GaN. Ga outdiffusion to the surface of thin (500 A) W films was found after annealing at 1,100 C, but not at 1000 C. Interfacial abruptness increased by 300A after 1,100 C annealing. In the case of WSi{sub X} (X=0.45), Ga outdiffusion was absent even at 1,100 C, but again there was interfacial broadening and some phase changes in the WSi{sub X}. On In{sub 0.5}Ga{sub 0.5}N, a minimum specific contact resistivity of 1.5 x10{sup -5}{Omega}cm{sup 2} was obtained for WSi{sub X} annealed at 700 C. These contacts retained a smooth morphology and abrupt interfaces to 800 C. Graded In{sub X}Ga{sub 1-X}N layers have been employed on GaAs/AlGaAs HBTs (heterojunction bipolar transistors), replacing conventional In{sub X}Ga{sub 1-X}As layers. R{sub C} values of 5x10{sup -7}{Omega}cm{sup 2} were obtained for nonalloyed Ti/Pt/Au on the InGaN, and the morphologies were superior to those of InGaAs contact layers. This proves to have significant advantages for fabrication of sub-micron HBTs. Devices with emitter dimensions of 2x5{mu}m{sup 2} displayed gains of 35 for a base doping level of 7x10{sup 19}cm{sup -3} and stable long-term behavior.

Microtags are microscopic computer-generated holograms with 130-nm features and are mass-producible with EUVL. This fabrication method renders microtags difficult to counterfeit. Applications includ tagging and tracking of microprocessors, memory chips, currencey, and credit cards.

In the present study we are developing an experimental fracture material property test method specific to dynamic fragmentation. Spherical test samples of the metals of interest are subjected to controlled impulsive stress loads by acceleration to high velocities with a light-gas launcher facility and subsequent normal impact on thin plates. Motion, deformation and fragmentation of the test samples are diagnosed with multiple flash radiography methods. The impact plate materials are selected to be transparent to the x-ray method so that only test metal material is imaged. Through a systematic series of such tests, both strain-to-failure and fragmentation resistance properties are determined through this experimental method. Fragmentation property data for several steels, copper, aluminum, tantalum and titanium have been obtained to date. Aspects of the dynamic data have been analyzed with computational methods to achieve a better understanding of the processes leading to failure and fragmentation, and to test an existing computational fragmentation model.

Neutron powder diffraction at pressures to 6 kbar in gaseous Ne has been used to study the pressure-induced phase transition and compressibilities of Na{sub 2}CsC{sub 60}. The pressure-induced phase can be achieved by compression to about 5 kbar at room temperature. If cooled, this phase can be retained below 200 K upon release of the pressure. The structure is orthorhombic as previously reported (but may differ in its detailed crystal structure) with lattice constants near 80 K and ambient pressure of a=9.385 A, b=10.06 A, and c=14.36 A. Corresponding linear compressibilities are 0.0004, 0014, and 0.0017 kbar{sup -1}, respectively. Identical pressure temperature cycling results in a superconductor with an unexpectedly low pressure dependence for {Tc} while in this phase. Models for the superconducting behavior of this compound are discussed.

In order to support advanced manufacturing, Sandia has acquired the capability to produce plastic prototypes using stereolithography. Currently, these prototypes are used mainly to verify part geometry and ``fit and form`` checks. This project investigates methods for rapidly testing these plastic prototypes, and inferring from prototype test data actual metal part performance and behavior. Performances examined include static load/stress response, and structural dynamic (modal) and vibration behavior. The integration of advanced non-contacting measurement techniques including scanning laser velocimetry, laser holography, and thermoelasticity into testing of these prototypes is described. Photoelastic properties of the epoxy prototypes to reveal full field stress/strain fields are also explored.

W, WSi{sub 0.44} and Ti/Al contacts were examined on n{sup +} In{sub 0.65}Ga{sub 0.35}N, InN and In{sub 0.75}Al{sub 0.25}N. W was found to produce low specific contact resistance ({rho}{sub c} {approximately} 10{sup {minus}7} {Omega} {center_dot}cm{sup 2}) ohmic contacts to InGaN, with significant reaction between metal and semiconductor at 900 {degrees}C mainly due to out diffusion of In and N. WSi{sub x} showed an as-deposited {rho}{sub c} of 4{times}10{sup {minus}7} {Omega} {center_dot}cm{sup 2} but this degraded significantly with subsequent annealing. Ti/Al contacts were stable to {approximately} 600 {degrees}C ({rho}{sub c} {approximately} 4{times}10{sup {minus}7} {Omega} {center_dot}cm{sup 2} at {le}600 {degrees}C). The surfaces of these contacts remain smooth to 800 {degrees}C for W and WSi{sub x} and 650 {degrees}C for Ti/Al. InN contacted with W and Ti/Al produced ohmic contacts with {rho}{sub c} {approximately} 10{sup {minus}7} {Omega} {center_dot}cm{sup 2} and for WSi{sub x} {rho}{sub c} {approximately} 10{sup {minus}6} {Omega} {center_dot}cm{sup 2}. All remained smooth to {approximately} 600 {degrees}C, but exhibited significant interdiffusion of In, N, W and Ti respectively at higher temperatures. The contact resistances for all three metalization schemes were {ge} 10{sup {minus}4} {Omega} {center_dot}cm{sup 2} on InAlN, and degrades with subsequent annealing. The Ti/Al was found to react with the InAlN above 400 {degrees}C, causing the contact resistance to increase rapidly. W and WSi{sub x} proved to be more stable with {rho}{sub c} {approximately} 10{sup {minus}2} and 10{sup {minus}3} {Omega} {center_dot}cm{sup 2} up to 650 {degrees}C and 700 {degrees}C respectively.

As photovoltaic (PV) electrical power systems gain increasing acceptance for both off-grid and utility-interactive applications, the safety, durability, and performance of these systems gains in importance. Local and state jurisdictions in many areas of the country require that all electrical power systems be installed in compliance with the requirements of the National Electrical Code{reg_sign} (NEC{reg_sign}). Utilities and governmental agencies are now requiring that PV installations and components also meet a number of Institute of Electrical and Electronic Engineers (IEEE) standards. PV installers are working more closely with licensed electricians and electrical contractors who are familiar with existing local codes and installation practices. PV manufacturers, utilities, balance of systems manufacturers, and standards representatives have come together to address safety and code related issues for future PV installations. This paper addresses why compliance with the accepted codes and standards is needed and how it is being achieved.

Phase II work for this Laboratory Directed Research and Development project is presented. Historically, high velocity, solid, electrically conducting armatures or projectiles have been utilized to generate or magnify existing electric fields in magnetohydrodynamic (MHD) devices. Useful power can be extracted from high velocity ionized, electrically conductive plasma jets. The MHD device current output can be switched to power other devices. The purpose of this project is to investigate the use of an Explosively-Driven Ionized Plasma Jet Generator (EDMG) to more efficiently obtain velocities much higher than can be achieved with solid armatures or projectiles. The armature velocity is one of the more important parameters in the electric field magnification process. The ionized plasma jet is generated by explosively collapsing a gas (neon, argon, xenon, hydrogen) filled cavity and directing the jet through a shocktube or core of an MHD device. Data are presented for two different size and configuration explosive drivers, one explosive (COMP-C4), one gas (argon), different driver pressures (90-200 psia), different shocktube or test section pressures (0.01-11.7 psia), and for two different shocktube inside dimensions. Measured time-of-arrival, current, voltage, resistance, power and energy data are presented for tests conducted. Measured time-of-arrival and plasma flow velocity data are compared to the predicted CTH hydrocode data. CTH code calculations are also presented to compare EDMG performance of various test gases and various explosive liner materials.

The International Security Program Initiative at Sandia National Laboratories (SNL) is dedicated to achieving a global nuclear security structure that reduces the danger of nuclear and other weapons of mass destruction. SNL is the principle Department of Energy (DOE) laboratory, jointly funded by the DOE and the Department of Defense (DoD), and is responsible for developing technology, concepts, and hardware to protect nuclear weapons and materials at facilities, and during transportation. SNL is working cooperatively with scientists and engineers in various institutes, laboratories, and other organizations within the countries of the Former Soviet Union (FSU) to reduce the risk of nuclear weapons proliferation. One major step toward achieving worldwide protection and control of nuclear materials and weapons proliferation is being accomplished by the DOE National Laboratories on work with the FSU in the area of Material Protection, Control, and Accountability (MPC&A). This report focuses on the accomplishments and status of work under the MPC&A program at Sandia. In addition, brief summaries of other areas of FSU cooperation are included such as Industrial Partnering Program (IPP); Lab-to-Lab; Safe and Secure Dismantlement (SSD); Safety and Security Technology; and Energy and Environment.

This report discusses a novel fabrication process to produce nearly perfect optics. The process utilizes vacuum deposition techniques to optimally modify polished optical substrate surfaces. The surface figure, i.e. contour of a polished optical element, is improved by differentially filling in the low spots on the surface using flux from a physical vapor deposition source through an appropriate mask. The process is expected to enable the manufacture of diffraction-limited optical systems for the UV, extreme UV, and soft X-ray spectral regions, which would have great impact on photolithography and astronomy. This same technique may also reduce the fabrication cost of visible region optics with aspheric surfaces.

Hydrous Metal Oxides (HMOs) are chemically synthesized materials which contain a homogeneous distribution of ion exchangeable alkali cations that provide charge compensation to the metal-oxygen framework. In terms of the major types of inorganic ion exchangers defined by Clearfield, these amorphous HMO materials are similar to both hydrous oxides and layered oxide ion exchangers (e.g., alkali metal titanates). For catalyst applications, the HMO material serves as an ion exchangeable support which facilitates the uniform incorporation of catalyst precursor species. Following catalyst precursor incorporation, an activation step is required to convert the catalyst precursor to the desired active phase. Considerable process development activities at Sandia National Laboratories related to HMO materials have resulted in bulk hydrous titanium oxide (HTO)- and silica-doped hydrous titanium oxide (HTO:Si)-supported NiMo catalysts that are more active in model reactions which simulate direct coal liquefaction (e.g., pyrene hydrogenation) than commercial {gamma}-Al{sub 2}O{sub 3}-supported NiMo catalysts. However, a fundamental explanation does not exist for the enhanced activity of these novel catalyst materials; possible reasons include fundamental differences in support chemistry relative to commercial oxides, high surface area, or catalyst preparation effects (ion exchange vs. incipient wetness impregnation techniques). The goals of this paper are to identify the key factors which control sulfided NiMo catalyst activity, including those characteristics of HTO- and HTO:Si-supported NiMo catalysts which uniquely set them apart from conventional oxide supports.

During April-May, 1995, Sandia National Laboratories, in cooperation with Trans-Pacific Geothermal Corporation, drilled a 5825{prime} exploratory slimhole (3.85 in. diameter) in the Vale Known Geothermal Resource Area (KGRA) near Vale, Oregon. This well was part of Sandia`s program to evaluate slimholes as a geothermal exploration tool. During drilling we performed several temperature logs, and after drilling was complete we performed injection tests, bailing from a zone isolated by a packer, and repeated temperature logs. In addition to these measurements, the well`s data set includes: 2714{prime} of continuous core (with detailed log); daily drilling reports from Sandia and from drilling contractor personnel; daily drilling fluid records; numerous temperature logs; pressure shut-in data from injection tests; and comparative data from other wells drilled in the Vale KGRA. This report contains: (1) a narrative account of the drilling and testing, (2) a description of equipment used, (3) a brief geologic description of the formation drilled, (4) a summary and preliminary interpretation of the data, and (5) recommendations for future work.

New pour-in-place, low density, rigid polyurethane foam kits have been developed to mechanically stabilize damaged explosive ordnance. Although earlier foam systems used chlorofluorocarbons as blowing agents, the current versions rely on carbon dioxide generated by the reaction of isocynates with water. In addition, these kits were developed to manually generate small quantifies of rigid foam in the field with minimal or no protective equipment. The purpose of this study was to evaluate and summarize available hazard information for the components of these rigid foam kits and to provide recommendations for personal protective equipment to be used while performing the manual combination of the components. As with most rigid foam systems, these kits consist of two parts, one a mixture of isocyanates; the other, a combination of polyols, surfactants, and amine catalysts. Once completely deployed, the rigid foam is non-toxic. The components, however, have some important health effects which must be considered when establishing handling procedures.

In this continued study, the microstructural evolution and peel strength as a function of thermal aging were evaluated for four Sn-Ag solders deposited on double layered Ag-Pt metallization. Additionally, activation energies for intermetallic growth over the temperature range of 134 to 190{degrees}C were obtained through thickness measurements of the Ag-Sn intermetallic that formed at the solder-metallization interface. It was found that Bi-containing solders yielded higher activation energies for the intermetallic growth, leading to thicker intermetallic layers at 175 and 190{degrees}C for times of 542 and 20.5 hrs, respectively, than the solders free of Bi. Complete reaction of the solder with the metallization occurred and lower peel strengths were measured on the Bi-containing solders. In all solder systems, a Ag-Sn intermetallic thickness of greater than {approximately}7 {mu}m contributed to lower peel strength values. The Ag-Sn binary eutectic composition and the Ag-Sn-Cu ternary eutectic composition solders yielded lower activation energies for intermetallic formation, less microstructural change with time, and higher peel strengths; these solder systems were resilient to the effects of temperatures up to 175{degrees}C. Accelerated isothermal aging studies provide useful criteria for recommendation of materials systems. The Sn-Ag and Sn-Ag-Cu eutectic compositions should be considered for future service life and reliability studies based upon their performance in this study.

Experimental results and a mathematical model are presented to describe differential evaporation rates in electron beam melting of titanium alloys containing aluminum and vanadium. Experiments characterized the evaporation rate of commercially pure titanium, and vapor composition over titanium with up to 6% Al and 4.5% V content as a function of beam power, scan frequency and background pressure. The model is made up of a steady-state heat and mass transport model of a melting hearth and a model of transient thermal and flow behavior near the surface. Activity coefficients for aluminum and vanadium in titanium are roughly estimated by fitting model parameters to experimental results. Based on the ability to vary evaporation rate by 10-15% using scan frequency alone, we discuss the possibility of on-line composition control by means of intelligent manipulation of the electron beam.

Thermal, electrochemical and transition metal mediated reactions of phosphaacetylene monomers were conducted in attempts to form novel polyphosphaacetylenes as a new class of potentially electrically conducting polymers. Molecular modeling was used to simulate the molecular conformations of optimized, isolated oligomers to identify the proper monomeric repeat units for highly conjugated molecules. Electrodeposition of suitable monomers led to low molecular weight oligomers. Thermal polymerization of phosphaacetylene monomers bearing aromatic substituents ed to the formation of polyhedral cage oligomers. Under metathesis polymerization conditions the phosphaacetylene monomers form unique complexes via an unprecedented sequence of intermediates which suggest that metathesis to linear oligomers is achievable. Conductivity measurements on electrodeposited oligomers indicate modest electrical conductivity.

This study examines, from a systems engineering design perspective, the potential of kinetic energy weapons being used in the role of a conventional strategic weapon. Within the Department of Energy (DOE) complex, strategic weapon experience falls predominantly in the nuclear weapons arena. The techniques developed over the years may not be the most suitable methodologies for use in a new design/development arena. For this reason a more fundamental approach was pursued with the objective of developing an information base from which design decisions might be made concerning the conventional strategic weapon system concepts. The study examined (1) a number of generic missions, (2) the effects of a number of damage mechanisms from a physics perspective, (3) measures of effectiveness (MOE`s), and (4) a design envelope for kinetic energy weapon concepts. With the base of information a cut at developing a set of high-level system requirements was made, and a number of concepts were assessed against these requirements.

We describe measurements, modeling, and mitigation experiments on the effects of anode and cathode plasmas in applied-B ion diodes. We have performed experiments with electrode conditioning and cleaning techniques including RF discharges, anode heating, cryogenic cathode cooling and anode surface coatings that have been successful in mitigating some of the effects of electrode contamination on ion diode performance on both the SABRE and PBFA accelerators. We are developing sophisticated spectroscopic diagnostic techniques that allow us to measure the electric and magnetic fields in the A-K gap, we compare these measured fields with those predicted by our 3-D particle-in-cell (PIC) simulations of ion diodes, and we measure anode and cathode plasma densities and expansion velocities. We are continuing to develop E-M simulation codes with fluid-PIC hybrid models for dense plasmas, in order to understand the role of electrode plasmas in ion diode performance. Our strategy for improving high power ion diode performance is to employ and expand our capabilities in measuring and modeling A-K gap plasmas and leverage our increased knowledge into an increase in total ion beam brightness to High Yield Facility (HYF) levels.

The high peak power, single-pulse technology developed for government programs during the mid-60`s through the mid-80`s is being adapted for use in continuously operating, high average power commercial materials processing applications. A new thermal surface treatment technology, called ion beam surface treatment (BEST), uses repetitive high energy (kJ`s per pulse), pulsed ({le}500 ns) ion beams to directly deposit energy in the top 1-20 micrometers of the surface of any material. A high average power IBEST processing system is made up of a magnetic pulse compressor (MPC) a magnetically confined anode plasma (MAP) ion beam source, an ion beam transport system, a materials handling system and various cooling and reset systems. System issues such as cost, reliability, size, maintainability, and design-for-manufacturability that were of secondary importance behind specific performance requirements for the earlier government applications are now the primary issues in proposed industrial systems. Research systems are now obtaining lifetime, reliability, and design-rules information for high average power short-pulse components. Beam sources are being developed that are suitable for industrial systems operating at 5-100 kW, 0.1-2.0 MeV, and {le}500 ns pulse widths. Capitol equipment costs, operating and financing costs, and sizing issues are being weighed against specific economic benefits obtained in short-pulse ion beam treatment of selected products. Dependable equipment designers and suppliers, facility integrator, and servicing organizations are being combined with development teams from end-user companies for final technology integration into major manufacturing facilities. An BEST prototype commercial system is being designed and fabricated by QM Technologies for initial operation in mid-1997.

The Molina Member of the Wasatch Formation has been cored in order to assess the presence/absence and character of microbial communities in the deep subsurface. Geological study of the Molina Member was undertaken in support of the microbiological tasks of this project, for the purposes of characterizing the host strata and of assessing the potential for post-depositional introduction of microbes into the strata. The Molina Member comprises a sandy fluvial unit within a formation dominated by mudstones. Sandy to conglomeratic deposits of braided and meandering fluvial systems are present on the western and eastern margins of the basin respectively, although the physical and temporal equivalence of these systems cannot be proven. Distal braided facies of planar-horizontal bedded sandstones are recognized on the western margin of the basin. Natural fractures are present in all Molina sandstones, commonly as apparent shear pairs. Core from the 1-M-18 well contains natural fractures similar to those found in outcrops, and has sedimentological affinities to the meandering systems of the eastern margin of the basin. The hydrologic framework of the Molina, and thus any potential post-depositional introduction of microbes into the formation, should have been controlled by approximately east-west flow through the natural fracture system, the geometries and extent of the sandstones in which the fractures occur, and hydraulic gradient. Migration to the well site, from outcropping recharge areas at the edge of the basin, could have started as early as 40 million years ago if the cored strata are connected to the eastern sedimentary system.

This study analyzes findings from a national survey of 2,490 randomly selected members of the US public conducted between September 30 and November 14, 1995. It provides an over time comparison of public perceptions about nuclear weapons risks and benefits and key nuclear policy issues between 1993 and 1995. Other areas of investigation include policy preferences regarding nuclear proliferation, terrorism, US/Russian nuclear cooperation, and personal security. Public perceptions of post-cold war security were found to be evolving in unexpected ways. The perceived threat of nuclear conflict involving the US had not declined, and the threat of nuclear conflict between other countries and fears of nuclear proliferation and terrorism had increased. Perceived risks associated with managing the US nuclear arsenal were also higher. Perceptions of external and domestic benefits from US nuclear weapons were not declining. Support was found for increasing funding for nuclear weapons safety, training, and maintenance, but most respondents favored decreasing funding for developing and testing new nuclear weapons. Strong support was evident for programs and funding to prevent nuclear proliferation and terrorism. Though skeptical that nuclear weapons can be eliminated, most respondents supported reducing the US nuclear arsenal, banning nuclear test explosions, and ending production of fissile materials to make nuclear weapons. Statistically significant relationships were found between perceptions of nuclear weapons risks and benefits and policy and spending preferences. Demographic variables and basic social and political beliefs were systematically related both to risk and benefit perceptions and policy and spending options.

This document provides an overview of the processes used to access the performance of the Waste Isolation Pilot Plant (WIPP). The quantitative metrics used in the performance-assessment (PA) process are those put forward in the Environmental Protection Agency`s Environmental Standards for the Management and Disposal of Spent Nuclear Fuel, HIgh-LEvel and transuranic radioactive Wastes (40 CFR 191).

A bench-scale experiment was designed and constructed to determine the effective thermal diffusivity of crushed tuff. Crushed tuff particles ranging from 12.5 mm to 37.5 mm (0.5 in. to 1.5 in.) were used to fill a cylindrical volume of 1.58 m{sup 3} at an effective porosity of 0.48. Two iterations of the experiment were completed; the first spanning approximately 502 hours and the second 237 hours. Temperatures near the axial heater reached 700 degrees C, with a significant volume of the test bed exceeding 100 degrees C. Three post-test analysis techniques were used to estimate the thermal diffusivity of the crushed tuff. The first approach used nonlinear parameter estimation linked to a one dimensional radial conduction model to estimate thermal diffusivity from the first 6 hours of test data. The second method used the multiphase TOUGH2 code in conjunction with the first 20 hours of test data not only to estimate the crushed tuffs thermal diffusivity, but also to explore convective behavior within the test bed. Finally, the nonlinear conduction code COYOTE-II was used to determine thermal properties based on 111 hours of cool-down data. The post-test thermal diffusivity estimates of 5.0 x 10-7 m{sup 2}/s to 6.6 x 10-7 m{sup 2}/s were converted to effective thermal conductivities and compared to estimates obtained from published porosity-based relationships. No obvious match between the experimental data and published relationships was found to exist; however, additional data for other particle sizes and porosities are needed.

The `Red Forest` radioactive waste burials created during emergency clean-up activities at Chernobyl Nuclear Power Plant represent a serious source of radioactive contamination of the local ground water system with 9OSr concentration in ground water exceeding the drinking water standard by 3-4 orders of magnitude. In this paper we present results of our hydrogeological and radiological `Red Forest` site characterization studies, which allow us to estimate 9OSr subsurface migration parameters. We use then these parameters to assess long terrain radionuclide transport to groundwater and surface water, and to analyze associated health risks. Our analyses indicate that 9OSr transport via ground water pathway from `Red Forest` burials to the adjacent Pripyat River is relatively insignificant due to slow release of 9OSr from the waste burials (less than 1% of inventory per year) and due to long enough ground water residence time in the subsurface, which allows substantial decay of the radioactive contaminant. Tins result and our previous analyses indicate, that though conditions of radioactive waste storage in burials do not satisfy Ukrainian regulation on radiation protection, health risks caused by radionuclide migration to ground water from `Red Forest` burials do not justify application of expensive countermeasures.

Sandia now has the capability to evaluate stresses during cure of epoxies with finite element codes. Numerous material parameters are needed as input to these codes. I present a relatively quick set of tests which enable evaluation of the required thermophysical properties. Ease and accuracy of the tests improve as the reaction rate of the thermoset slows. Material parameters for common encapsulants at Sandia are presented in tables.

No abstract available.

Six boreholes were drilled during the geologic characterization and diagnostics of the Weeks Island sinkhole that is over the two-tiered salt mine which was converted for oil storage by the U.S. Strategic Petroleum Reserve. These holes were drilled to provide for geologic characterization of the Weeks Island Salt Dome and its overburden in the immediate vicinity of the sinkhole (mainly through logs and core); to establish a crosswell configuration for seismic tomography; to establish locations for hydrocarbon detection and tracer injection; and to provide direct observations of sinkhole geometry and material properties. Specific objectives of the logging program were to: (1) identify the top of and the physical state of the salt dome; (2) identify the water table; (3) obtain a relative salinity profile in the aquifer within the alluvium, which ranges from the water table directly to the top of the Weeks Island salt dome; and (4) identify a reflecting horizon seen on seismic profiles over this salt dome. Natural gamma, neutron, density, sonic, resistivity and caliper logs were run.

An analytical and experimental study is conducted to investigate the effect of isolator locations on the effectiveness of vibration isolation systems. The study uses isolators with fixed properties and evaluates potential improvements to the isolation system that can be achieved by optimizing isolator locations. Because the available locations for the isolators are discrete in this application, a Genetic Algorithm (GA) is used as the optimization method. The system is modeled in MATLAB{trademark} and coupled with the GA available in the DAKOTA optimization toolkit under development at Sandia National Laboratories. Design constraints dictated by hardware and experimental limitations are implemented through penalty function techniques. A series of GA runs reveal difficulties in the search on this heavily constrained, multimodal, discrete problem. However, the GA runs provide a variety of optimized designs with predicted performance from 30 to 70 times better than a baseline configuration. An alternate approach is also tested on this problem: it uses continuous optimization, followed by rounding of the solution to neighboring discrete configurations. Results show that this approach leads to either infeasible or poor designs. Finally, a number of optimized designs obtained from the GA searches are tested in the laboratory and compared to the baseline design. These experimental results show a 7 to 46 times improvement in vibration isolation from the baseline configuration.

This work addresses specification and design of reliable safety-critical systems, such as nuclear reactor control systems. Reliability concerns are addressed in complimentary fashion by different fields. Reliability engineers build software reliability models, etc. Safety engineers focus on prevention of potential harmful effects of systems on environment. Software/hardware correctness engineers focus on production of reliable systems on the basis of mathematical proofs. The authors think that correctness may be a crucial guiding issue in the development of reliable safety-critical systems. However, purely formal approaches are not adequate for the task, because they neglect the connection with the informal customer requirements. They alleviate that as follows. First, on the basis of the requirements, they build a model of the system interactions with the environment, where the system is viewed as a black box. They will provide foundations for automated tools which will (a) demonstrate to the customer that all of the scenarios of system behavior are presented in the model, (b) uncover scenarios not present in the requirements, and (c) uncover inconsistent scenarios. The developers will work with the customer until the black box model will not possess scenarios (b) and (c) above. Second, the authors will build a chain of several increasingly detailed models, where the first model is the black box model and the last model serves to automatically generated proved executable code. The behavior of each model will be proved to conform to the behavior of the previous one. They build each model as a cluster of interactive concurrent objects, thus they allow both top-down and bottom-up development.

Effectiveness and efficiency of software development can be greatly increased by writing modularized code using informal (styles) and formal (standards) work approaches. Software development is about connecting pieces into a coherent whole. Thus consistent work approaches provide a structure that allows individuals and teams to minimize the time and thought put into making these connections. These investments in structure return even more benefits in the maintenance phase when old code has to be examined by new programmers, or after time has passed. We present some examples of coding style for Avenue: a simplified form of Hungarian notation (notationHungarian, stringCustomerName, etc.), script naming prefixes and suffixes, and options in script headers. We demonstrate several modular, object-like utility scripts that can be used alone or combined into other utilities. These include developer tools such as a System.Echo substitute for Windows, a Window inspector, and a script for detecting and dealing with multiple display resolutions.

We present an in situ technique for monitoring metal-organic vapor phase epitaxy growth by normal-incidence reflectance. This technique is used to calibrate the growth rate periodically and to monitor the growth process routinely. It is not only a precise tool to measure the growth rate, but also very useful in identifying unusal problems during a growth run, such as depletion of source material, deterioration of surface morphology, and problems associated with an improper growht procedure. We will also present an excellent reproducibility ({+-}0.3% over a course of more than 100 runs) of the cavity wavelength of vertical-cavity surface emitting laser structures with periodic calibration by this in situ technique.

Electronic and electrical system protection design can be used to eliminate deleterious effects from lightning, electromagnetic interference, and electrostatic discharges. Evaluation of conventional lightning protection systems using advanced computational modeling in conjunction with rocket-triggered lightning tests suggests that currently used lightning protection system design rules are inadequate and that significant improvements in best practices used for electronic and electrical system protection designs are possible. A case study of lightning induced upset and failure of a railway signal and control system is sketched.

How can the public play a role in decisions involving complicated scientific arguments? This paper describes a public participation exercise in which stakeholders used multiattribute utility analysis to select a site for a hazardous waste facility. Key to success was the ability to separate and address the two types of judgements inherent in environmental decisions: technical judgements on the likely consequences of alternative choices and value judgements on the importance or seriousness of those consequences. This enabled technical specialists to communicate the essential technical considerations and allowed stakeholders to establish the value judgements for the decision. Although rarely used in public participation, the multiattribute utility approach appears to provide a useful framework for the collaborative resolution of many complex environmental decision problems.

Two polyurethane systems, EN-7 and L-100, have a long history as encapsulants and coatings in Sandia programs. These materials contain significant amounts of toluene diisocyanate (TDI), a suspect human carcinogen. As part of efforts to reduce the use of hazardous materials in the workplace, PET-90A, a polyurethane with less than 0.1% free TDI, was identified as a candidate for new applications and as a replacement for the more hazardous polyurethanes in selected programs. This report documents the results of a two-year accelerated aging study of PET-90A, EN-7, and L-100 polyurethane elastomers to characterize the effect of 135{degrees}F isothermal aging on selected physical, electrical, mechanical and thermal properties. In general, there was very little change in properties over the two year period for the three elastomers. The largest changes occurred in EN-7, which is the polyurethane with the longest service history in Sandia applications.

Vector network analyzers provide a convenient way to measure scattering parameters of a variety of microwave devices. However, these instruments, unlike oscilloscopes, require a high degree of user knowledge and expertise. Measurement calibration or error correction must be done prior to use. There are many ways to make poor measurement or measurement. Check standards have been used to verify that the network analyzer is operating properly. A computer program was developed to automatically measure a check standard and compare the new measurements with an historical database of measurements of the check standard device. The program can acquire new measurement data from selected check standards, plot the new data against the mean and standard deviation of prior data for the check standard, and update the database files for the check standard. This paper describes the function of the software including a discussion of its capabilities. The way in which the software is used in our lab is also described. Finally, examples are given of how the software can detect potential measurement problems.

Fe/KClO{sub 4} pyrotechnic mixtures are used in thermal batteries to provide the heat necessary to bring the battery stack to operating temperatures of 550 to 600 C. This heat source is normally used as discs pressed from bulk powder. To evaluate the consequences associated with unexpected ignition of large amounts of heat powder, combustion of 84% Fe/16% KClO{sub 4} heat powders was conducted for various scenarios under controlled conditions and the response documented. Increasing amounts of heat powder--up to 8 lbs--were ignited in both unconfined and confined (sealed) containers in a remote area. The containers were thermocoupled and the resulting burning filmed with a standard video camera, high-speed (1,000 frames/s) film and video cameras, and an infrared video camera. A 20- minute video of the burning under the various conditions is presented.

Sandia`s Risk Management and NEPA Department recognized the need for hazard and environmental data analysis and management to support the line managers` need to know, understand, manage and document the hazards inherent in their facilities and activities. ISEEMS (Integrated Safety, Environmental, & Emergency Management System) was developed in response to this need. ISEEMS takes advantage of the fact that there is some information needed for the NEPA process that is also needed for the safety documentation process. The ISEEMS process enables Sandia to identify and manage hazards and environmental concerns at a level of effort commensurate with the hazards themselves by adopting a necessary and sufficient (graded) approach to compliance. The Preliminary Hazard Screening module of ISEEMS determines the facility or project activity hazard classification and facility designation. ISEEMS` geo-referenced icon allows immediate, visual integration of hazard information across geographic boundaries resulting in significant information compression. At Sandia, ISEEMS runs on the Sandia Internal Restricted Network, in an MS-Windows environment on standard PC hardware. The possibility of transporting ISEEMS to a ``WEB-like`` environment is being explored.

This paper presents a paradigm for integrating the many facets of ES&H management based on the necessary and sufficient control of hazards and the resulting risks through a systems approach. The paradigm answers the question ``What is the best approach to managing ES&H to increase value, reduce risk, and improve satisfaction?`` Hazard identification is the foundation of integrated ES&H management. Knowledge of risk is essential to the necessary and sufficient management of risk. A systems approach to identifying and managing risks is essential in achieving integrated ES&H management. Feedback is discussed. The objectives can be applied to the function of risk management using the ``Know, Understand, Manage and Document`` paradigm. The organizational structure is crucial to the success of integrated ES&H management.

The thermal response under geothermal-borehole conditions of a conventional thermal battery was evaluated for various designs by numerical simulations using a finite-element thermal model. This technology, which is based on molten salts, may be suitable as a power source for geothermal borehole applications for data logging. Several promising candidate electrolytes were identified for further study.

Three constitutive models are recommended as candidates for describing the deformation of crushed salt. These models are generalized to three-dimensional states of stress to include the effects of mean and deviatoric stress and modified to include effects of temperature, grain size, and moisture content. A database including hydrostatic consolidation and shear consolidation tests conducted on Waste Isolation Pilot Plant (WIPP) and southeastern New Mexico salt is used to determine material parameters for the models. To evaluate the capability of the models, parameter values obtained from fitting the complete database are used to predict the individual tests. Finite element calculations of a WIPP shaft with emplaced crushed salt demonstrate the model predictions.

A post-processing, selective micro-chemical vapor deposition (``micro-CVD``) technology for the deposition of catalytic films on surface-micromachined, nitride-passivated polysilicon filaments has been investigated. Atmospheric pressure deposition of Pt on microfilaments was accomplished by thermal decomposition of Pt acetylacetonate; deposition occurs selectively only on those filaments which are electrically heated. Catalyst morphology, characterized by SEM, can be controlled by altering deposition time, filament temperature, and through the use of pulsed heating of the filament during deposition. Morphology plays an important role in determining the sensitivity of these devices when used as combustible gas sensors.

Semiconductor bridges (SCB) igniters were evaluated as possible replacements for conventional hot-wire igniters for use in thermal batteries. The all-fire and no-fire characteristics were determined using an up-down scheme; the Neyer/SENSIT program was used to analyze the data. The SCB igniters functioned with a higher no-fire level, relative to a hot-wire igniter, for a given all-fire level. This makes the SCB igniter safer and more reliable than its hot-wire counterpart. The SCB is very resistant to electrostatic discharge and does not require a sensitization mixture for ignition of the primary pyrotechnic charge. These factors, along with its amenability to large-scale production, make the SCB igniter ideally suited for use in thermal batteries.

Chemical-Mechanical Polishing (CMP) has emerged as an enabling technology for manufacturing multi-level metal interconnects used in high-density Integrated Circuits (IC). In this work we present extension of CMP from sub-micron IC manufacturing to fabrication of complex surface-micromachined Micro-ElectroMechanical Systems (MEMS). This planarization technique alleviates processing problems associated with fabrication of multi-level polysilicon structures, eliminates design constraints linked with non-planar topography, and provides an avenue for integrating different process technologies. We discuss the CMP process and present examples of the use of CMP in fabricating MEMS devices such as microengines, pressures sensors, and proof masses for accelerometers along with its use for monolithically integrating MEMS devices with microelectronics.

3-D quasistatic finite element codes are being used at Sandia to simulate large room and pillar mines in rock salt. The two examples presented in this paper are of mines supported by US DOE, under the auspices of the Strategic Petroleum Reserve program. One of the mines is presently used as an oil storage facility. These simulations, validated by field measurements and observations, have provided valuable insight into the failure mechanisms of room and pillar mines in rock salt. The calculations provided the basis for further investigation and the ultimate decision to decommission the DOE oil storage facility.

A large-scale dynamic compaction demonstration of natural salt was successfully completed. About 40 m{sup 3} of salt were compacted in three, 2-m lifts by dropping a 9,000-kg weight from a height of 15 m in a systematic pattern to achieve desired compaction energy. To enhance compaction, 1 wt% water was added to the relatively dry mine-run salt. The average compacted mass fractional density was 0.90 of natural intact salt, and in situ nitrogen permeabilities averaged 9X10{sup -14}m{sup 2}. This established viability of dynamic compacting for placing salt shaft seal components. The demonstration also provided compacted salt parameters needed for shaft seal system design and performance assessments of the Waste Isolation Pilot Plant.

An issue of paramount interest to US industry is the supply and quality of human resources available for this country`s scientific and technological activities. The changing composition of the workforce and the responsibility that an organization has to assure equal opportunity, give rise to various issues. This paper discusses some of the issues associated with the scientific and technical workforce. Specifically, it explores some of the questions pertaining to workforce composition and measures of workforce composition. This paper should be useful to those responsible for personnel policies.

All valid constitutive equations must satisfy two general invariance principles as well several other principles. In this paper the MDCF (Multimechanism Deformation Coupled Fracture) model for rock salt is shown to be thermodynamically consistent, coordinate invariant, frame indifferent, and physically admissible. Additionally, the stress rates used in the formulation are shown to be kinematically consistent with the Cauchy stress rates.

Over 100 candidates were examined, including commercial materials and many that were synthesized in house. The mixed oxides were based on Ti, V, Nb, Cr, Mo, W, Mn, Fe, Co, Ni, and Cu doped with other transition metals. A number of individual (single-metal) oxides were included for comparison. The candidates were tested in single cells with Li(Si) anodes and separators based on LiCl-KCl eutectic. Screening was done under constant-current conditions at current densities of 125 me/cm{sup 2} and, to a lesser extent, 50 me/cm{sup 2} at 500 C. Relative performance and limitations of the oxide cathodes are discussed.

The performance of PAN-based composite absorbers was evaluated in dynamic experiments at flow rates ranging from 25--100 bed volumes (BV) per hour. Composite absorbers with active components of ammonium molybdophosphate (AMP) PAN and K-Co ferrocyanide (KCoFC) PAN were used for separating Cs from a 1 M HNO{sub 3} + 1 M NaNO{sub 3} + 2 {times} 10{sup {minus}5} M CsCl acidic simulant solution. KCoFC-PAN and two other FC-based composite absorbers were tested for separating Cs from alkaline simulant solutions containing 0.01 M to 1 M NaOH and 1 M NaNO{sub 3} + x {times} 10{sup {minus}4} M CsCl. The efficiency of the Cs sorption on the AMP-PAN absorber from acidic simulant solutions was negatively influenced by the dissolution of the AMP active component. At flow rates of 50 BV/hr, the decontamination factor of about 10{sup 3} could be maintained for treatment of 380 BV of the feed. With the KCoFC-PAN absorber, the decontamination factor of about 10{sup 3} could be maintained for a feed volume as great as 1,800 BV. In alkaline simulant solutions, significant decomposition of the active components was observed, and the best performance was exhibited by the KCoFC-PAN absorber. Introductory experiments confirmed that Cs may be washed out of the composite absorbers. Regeneration of both absorbers for repetitive use was also found to be possible. The main result of the study is that PAN was proven to be a versatile polymer capable of forming porous composite absorbers with a large number of primary absorbers. The composite absorbers proved to be capable of withstanding the harsh acidic and alkaline conditions and significant radiation doses that may be expected in the treatment of US DOE wastes. A field demonstration is proposed as a follow-on activity.

Increased complexity of the computing environment is probably the most universal observation of developers going into Client/Server computing. The Lessons Learned document Provides some condensed bits of expertise gained by the Document Production System Redevelopment team. The intent is to distribute in a simplified format the knowledge the authors have gained, and to promote discussion of certain areas having unresolved or less-than-perfect resolution. Included are first, a description of the hardware and software used. The lists of hardware and software are a good basic guide for the components of a robust data server and provide a framework for subsequent discussion of technical points learned during the development. The second part of the document is a discussion of fine points about Novell, Sybase and Visual Basic as applied to the DPS/R development. Areas covered include the hardware of the database server, Novell operating system, Sybase database tools and Visual Basic.

The influence of minority carrier injection on the reactivation of hydrogen passivated Mg in GaN at 175 C has been investigated in p-n junction diodes. The dissociation of the neutral MgH complexes is greatly enhanced in the presence of minority carrier and the reactivation process follows second order kinetics. Conventional annealing under zero-bias conditions does not produce Mg-H dissociation until temperatures {ge} 450 C. These results provide an explanation for the e-beam induced reactivation of Mg acceptors in hydrogenated GaN. Exposure to a hydrogen plasma at 250 C of p-type GaN (Ca) prepared by either Ca{sup +} or Ca{sup +} plus P{sup +} coimplantation leads to a reduction in sheet carrier density of approximately an order of magnitude (1.6 {times} 10{sup 12} cm{sup {minus}2} to 1.8 {times} 10{sup 11} cm{sup {minus}2}), and an accompanying increase in hole mobility (6 cm{sup 2}/Vs to 18 cm{sup 2}/Vs). The passivation process can be reversed by post-hydrogenation annealing at 400--500 C under a N{sub 2} ambient. This reactivation of the acceptors is characteristic of the formation of neutral (Ca-H) complexes in the GaN. The thermal stability of the passivation is similar to that of Mg-H complexes in material prepared in the same manner (implantation) with similar initial doping levels. Hydrogen passivation of acceptor dopants in GaN appears to be a ubiquitous phenomenon, as it is in other p-type semiconductors.

Advanced electronic devices based on compound semiconductors often make use of selective area ion implantation doping or isolation. The implantation processing becomes more complex as the device dimensions are reduced and more complex material systems are employed. The authors review several applications of ion implantation to high performance junction field effect transistors (JFETs) and heterostructure field effect transistors (HFETs) that are based on compound semiconductors, including: GaAs, AlGaAs, InGaP, and AlGaSb.

This project studied hydrothermal synthesis as a route to producing green-emitting cathodoluminescent phosphorus isostructural with yttrium aluminum garnet (Y{sub 3}Al{sub 5}O{sub 12}, or YAG). Aqueous precipitation of Y, Gd, Al, Ga, and Tb salts produced amorphous gels, which were heated with water at 600 C and 3,200 bar to produce crystalline YAG:Tb, Y{sub 3}Ga{sub 5}O{sub 12}:Tb, Y{sub 3}Al{sub 3}Ga{sub 2}O{sub 12}:Tb, and Gd{sub 3}Ga{sub 5}O{sub 12}:Tb powders. Process parameters were identified that yielded submicron YAG:Tb and Y{sub 3}Ga{sub 5}O{sub 12}:Tb powders without grinding. Cathodoluminescent efficiencies were measured as functions of power density at 600 V, using both the hydrothermal garnets and identical phosphor compositions synthesized at high temperatures. Saturation behavior was independent of synthetic technique, however, the hydrothermal phosphorus were less susceptible to damage (irreversible efficiency loss) at very high power densities (up to 0.1 W/cm{sup 2}). The fine grain sizes available with hydrothermal synthesis make it an attractive method for preparing garnet phosphorus for field emission, projection, and head-up displays.

Sandia National Laboratories is presently developing an additive component processing technology called Laser Engineered Net Shaping, (LENS{trademark}). This process allows complex 3-dimensional solid metallic objects to be directly fabricated from a CAD solid model. Currently, this process functions similar to the Stereo Lithography process in which a faceted file is generated from the CAD solid model and then sliced into a sequence of layers. The sliced file is then input into another interpreter program which converts the sliced file into a series of tool path patterns required to build the entire layer. The component is fabricated by first generating an outline of the key component features and then filled using a rastering technique. This file is then used to drive the laser system to produce the desired component one layer at a time. This process differs from present rapid prototyping (RP) processes in that a fully dense, metallic component can be produced using this process.

AlSb and AlAs{sub x}Sb{sub 1{minus}x} epitaxial films grown by metal-organic chemical vapor deposition were successfully doped p- or n-type using diethylzinc or tetraethyltin, respectively. AlSb films were grown at 500 C and 76 torr using trimethylamine or ethyldimethylamine alane and triethylantimony. The authors examined the growth of AlAsSb using temperature of 500 to 600 C, pressures of 65 to 630 torr, V/III ratios of 1--17, and growth rates of 0.3 to 2.7 {micro}m/hour in a horizontal quartz reactor. SIMS showed C and O levels below 2 {times} 10{sup 18} cm{sup {minus}3} and 6 {times} 10{sup 18} cm{sup {minus}3} respectively for undoped AlSb. Similar levels of O were found in AlAs{sub 0.16}Sb{sub 0.84} films but C levels were an order of magnitude less in undoped and Sn-doped AlAs{sub 0.16}Sb{sub 0.84} films. Hall measurements of AlAs{sub 0.16}Sb{sub 0.84} showed hole concentrations between 1 {times} 10{sup 17} cm{sup {minus}3} to 5 {times} 10{sup 18} cm{sup {minus}3} for Zn-doped material and electron concentrations in the low to mid 10{sup 18} cm{sup {minus}3} for Sn-doped material. They have grown pseudomorphic InAs/InAsSb quantum well active regions on AlAsSb cladding layers. Photoluminescence of these layers has been observed up to 300 K.

Chlorinated solvents as dense non-aqueous phase liquid (DNAPL) are present at a large number of hazardous waste sites across the U.S. and world. DNAPL is difficult to detect in the subsurface, much less characterize to any degree of accuracy. Without proper site characterization, remedial decisions are often difficult to make and technically effective, cost-efficient remediations are even more difficult to obtain. A new non-aqueous phase liquid (NAPL) characterization technology that is superior to conventional technologies has been developed and applied at full-scale. This technology, referred to as the Partitioning Interwell Tracer Test (PITT), has been adopted from oil-field practices and tailored to environmental application in the vadose and saturated zones. A PITT has been applied for the first time at full-scale to characterize DNAPL in the vadose zone. The PITT was applied in December 1995 beneath two side-by-side organic disposal pits at Sandia National Laboratories/New Mexico (SNL/NM) RCRA Interim Status Chemical Waste Landfill (CWL), located in Albuquerque, New Mexico. DNAPL, consisting of a mixture of chlorinated solvents, aromatic hydrocarbons, and PCE oils, is known to exist in at least one of the two buried pits. The vadose zone PITT was conducted by injecting a slug of non-partitioning and NAPL-partitioning tracers into and through a zone of interest under a controlled forced gradient. The forced gradient was created by a balanced extraction of soil gas at a location 55 feet from the injector. The extracted gas stream was sampled over time to define tracer break-through curves. Soil gas sampling ports from multilevel monitoring installations were sampled to define break-through curves at specific locations and depths. Analytical instrumentation such as gas chromatographs and a photoacoustical analyzers operated autonomously, were used for tracer detection.

The Accelerator Production of Tritium (APT) project has proposed a strategy to develop the APT authorization basis and safety case based on DOE orders and fundamental requirements for safe operation. The strategy is viable regardless of whether the APT is regulated by DOE or by an external regulatory body. Currently the operation of Department of Energy (DOE) facilities is authorized by DOE and regulated by DOE orders and regulations while meeting the environmental protection requirements of the Environmental Protection Agency (EPA) and the states. In the spring of 1994, Congress proposed legislation and held hearings related to requiring all DOE operations to be subject to external regulation. On January 25, 1995, DOE, with the support of the White House Council on Environmental Quality, created the Advisory Committee on External Regulation of Department of Energy Nuclear Safety. This committee divided its recommendations into three areas: (1) facility safety, (2) worker safety, and (3) environmental protection. In the area of facility safety the committee recommended external regulation of DOE nuclear facilities by either the Nuclear Regulatory Commission (NRC) or a restructured Defense Nuclear Facilities Safety Board (DNFSB). In the area of worker safety, the committee recommended that the Occupational Safety and Health Administration (OSHA) regulate DOE nuclear facilities. In the environmental protection area, the committee did not recommend a change in the regulation by the EPA and the states of DOE nuclear facilities. If these recommendations are accepted, all DOE nuclear facilities will be impacted to some extent.

When United States space missions involve launching vehicles carrying significant quantities of nuclear material, US law requires that prior to launch the mission be approved by the Office of the President. This approval is to be based on an evaluation of the nuclear safety risks associated with the mission and the projected benefits. To assist in the technical evaluation of risks for each mission, an Interagency Nuclear Safety Review Panel (INSRP) is instituted to provide an independent assessment of the mission risks. INSRP`s assessment begins with a review of the safety analysis for the mission completed by the organization proposing the mission and documented in a Safety Analysis Report (SAR). In addition, INSRP may execute other analyses it deems necessary. Results are documented and passed to the decision maker in a Safety Evaluation Report (SER). The INSRP review and evaluation process has been described in some detail in a number of papers.

A Multi-spectral Pushbroom Imaging Radiometer (MPIR) has been developed as a well-calibrated, imaging radiometer for studies of cloud properties from an unmanned aerospace vehicle platform. The instrument is designed to fly at altitudes up to 20 km and produce data from nine spectral detector modules. Each module has its own telescope optics, linear detector array, spectral filter, and necessary electronics. Cryogenic cooling for the long-wavelength infrared modules, as well as temperature regulation of the short- wavelength modules, is provided by a liquid nitrogen system designed to operate for multi-day missions. Pre- and post-flight calibration, combined with an on-board calibration chopper, provide an instrument with state-of-the-art radiometric measurement accuracies. Each module has a {+-}40{degree} across-track field-of-view and images a curved footprint onto its linear detector array. The long-wavelength array types have 256 detector elements while the short-wavelength arrays can have 512 elements. A modular design allows individual spectral bands to be changed to match the requirements for a particular mission.

Carbons derived from polymethylacrylonitrile (PMAN) have been studied for use as intercalation anodes in Li-ion cells. The effect of Si doping upon the electrochemical performance of PMAN carbons was studied using tetravinylsilane (TVS) and tetramethysilane (TMS) as sources of Si during the formation of the PMAN precursors. The carbons were characterized by galvanostatic cycling, cyclic voltammetry, and complex impedance. The presence of 9 to 11 w/o Si in the PMAN lattice greatly increased the irreversible capacity of these materials.

In lithium/thionyl chloride (Li/TC) cells, a lithium limited design was thought to be safer than a cathode limited design because the amount of lithium left in discharged cells would be minimal. However, lithium corrosion reduces the capacity faster than does cathode degradation during storage. The optimization of the ratio of lithium to carbon was studied, considering storage time and temperature. The efficiency of converting chemical energy into electrical energy has been studied for the case of D cells with surface area from 45 to 345 cm{sup 2}, under constant and various pulsed loads. Microcalorimetric monitoring of the heat output during discharge allowed the direct measurement of faradaic efficiency, and showed that self discharge is far more pervasive that previously acknowledged. Typical faradaic efficiencies for constant load varied from 30% at low current density to 90% at moderate and 75 % at high current density. Pulsed current further depresses these efficiencies, except at very low average current density.

The theoretical and numerical background for the finite element computer program, TORO II, is presented in detail. TORO II is designed for the multi-dimensional analysis of nonlinear, electromagnetic field problems described by the quasi-static form of Maxwell`s equations. A general description of the boundary value problems treated by the program is presented. The finite element formulation and the associated numerical methods used in TORO II are also outlined. Instructions for the use of the code are documented in SAND96-0903; examples of problems analyzed with the code are also provided in the user`s manual. 24 refs., 8 figs.

User instructions are given for the finite element, electromagnetics program, TORO II. The theoretical background and numerical methods used in the program are documented in SAND95-2472. The present document also describes a number of example problems that have been analyzed with the code and provides sample input files for typical simulations. 20 refs., 34 figs., 3 tabs.

The theoretical background for the finite element computer program, MPSalsa, is presented in detail. MPSalsa is designed to solve laminar, low Mach number, two- or three-dimensional incompressible and variable density reacting fluid flows on massively parallel computers, using a Petrov-Galerkin finite element formulation. The code has the capability to solve coupled fluid flow, heat transport, multicomponent species transport, and finite-rate chemical reactions, and to solver coupled multiple Poisson or advection-diffusion- reaction equations. The program employs the CHEMKIN library to provide a rigorous treatment of multicomponent ideal gas kinetics and transport. Chemical reactions occurring in the gas phase and on surfaces are treated by calls to CHEMKIN and SURFACE CHEMKIN, respectively. The code employs unstructured meshes, using the EXODUS II finite element data base suite of programs for its input and output files. MPSalsa solves both transient and steady flows by using fully implicit time integration, an inexact Newton method and iterative solvers based on preconditioned Krylov methods as implemented in the Aztec solver library.

The separator pellet in a thermal battery consists of electrolyte immobilized by a binder (typically, MgO powder). The melting point of the electrolyte determines the effective operating window for its use in a thermal battery. The development of a two-hour thermal battery required the use of a molten salt that had a lower melting point and larger liquidus range than the LiCl-KCl eutectic which melts at 352 C. Several candidate eutectic electrolyte systems were evaluated for their suitability for this application. One was the LiCl-LiBr-KBr eutectic used at Argonne National Laboratories for high-temperature rechargeable batteries for electric-vehicle applications. Using a custom-designed high-temperature conductivity cell, the authors were able to readily determine the liquidus region for the various compositions studied around the original eutectic for the LiBr-KBr-LiF system. The actual eutectic composition was found to be 60.0 m/o LiBr-37.5 m/o KBr-2.5 m/o LiF with a melting point of 324 {+-} 0.5 C.

In this paper the authors present the results of a coupled nonlinear finite element geomechanics model for reservoir compaction and well-to-well interactions for the high-porosity, low strength diatomite reservoirs of the Belridge field near Bakersfield, California. They show that well damage and failures can occur under the action of two distinct mechanisms: shear deformations induced by pore compaction, and subsidence, and shear deformations due to well-to-well interactions during production or water injection. They show such casting damage or failure can be localized to weak layers that slide or slip under shear due to subsidence. The magnitude of shear displacements and surface subsidence agree with field observations.

The oxidation and performance of the solid film lubricant used in a majority of the surety devices in the enduring stockpile have been investigated. Oxidation of this lubricant in air at 150 C produces a significant increase in the molybdenum oxide to sulfide ratio, indicative of degradation of the primary lubricating constituent of the composite lubricant. Oxidation is more extensive on samples that were burnished such that the substrate is exposed over a fraction of the surface, relative to those which were only lightly burnished. Friction results indicate that oxidation in air did not increase the initial or steady-state friction coefficient for lightly burnished surfaces. However, surfaces burnished to expose substrate material experienced a significant increase in both initial and steady-state friction. Oxidation of lubricated parts retrieved from aged stronglinks has also been demonstrated.

There are two main issues regarding thin film debonding. The first is the nucleation of interfacial cracks, while the second is the propagation of cracks. From a mechanical testing point of view, scratch testing primarily serves to address the former issue, while indentation testing is a method of addressing the latter. A new probing technique has been developed to test thin film mechanical properties. In the Microwedge Scratch Test (MWST), a wedge shaped diamond indenter tip is drawn along a fine line, while simultaneously being driven into the line. The authors compare microwedge scratching of Zone 1 and Zone T thin film specimens of sputtered W on SiO{sub 2}. Symptomatic of its poor mechanical properties, the Zone 1 film displays three separate crack systems. Because of its superior grain boundary strength, the Zone T film displayed only one of these--an interfacial crack system. Using bimaterial linear elastic fracture mechanics, governing equations are developed for propagating interfacial cracks, including expressions for strain energy release rate, bending strain, and mode mixity. Grain boundary fracture strength information may be deduced from the Zone 1 films, while adhesion may be inferred from the Zone T films.

Two models for gas-phase diffusion and advection in porous media, the Advective-Dispersive Model (ADM) and the Dusty-Gas Model (DGM), are reviewed. The ADM, which is more widely used, is based on a linear addition of advection calculated by Darcy`s Law and ordinary diffusion using Fick`s Law. Knudsen diffusion is often included through the use of a Klinkenberg factor for advection, while the effect of a porous medium on the diffusion process is through a porosity-tortuosity-gas saturation multiplier. Another, more comprehensive approach for gas-phase transport in porous media has been formulated by Evans and Mason, and is referred to as the Dusty- Gas Model (DGM). This model applies the kinetic theory of gases to the gaseous components and the porous media (or ``dust``) to develop an approach for combined transport due to ordinary and Knudsen diffusion and advection including porous medium effects. While these two models both consider advection and diffusion, the formulations are considerably different, especially for ordinary diffusion. The various components of flow (advection and diffusion) are compared for both models. Results from these two models are compared to isothermal experimental data for He-Ar gas diffusion in a low-permeability graphite. Air-water vapor comparisons have also been performed, although data are not available, for the low-permeability graphite system used for the helium-argon data. Radial and linear air-water heat pipes involving heat, advection, capillary transport, and diffusion under nonisothermal conditions have also been considered.

A review of mechanisms, models, and data relevant to the postulated phenomenon of enhanced vapor-phase diffusion in porous media is presented. Information is obtained from literature spanning two different disciplines (soil science and engineering) to gain a diverse perspective on this topic. Findings indicate that while enhanced vapor diffusion tends to correct the discrepancies observed between past theory and experiments, no direct evidence exists to support the postulated processes causing enhanced vapor diffusion. Numerical modeling analyses of experiments representative of the two disciplines are presented in this paper to assess the sensitivity of different systems to enhanced vapor diffusion. Pore-scale modeling is also performed to evaluate the relative significance of enhanced vapor diffusion mechanisms when compared to Fickian diffusion. The results demonstrate the need for additional experiments so that more discerning analyses can be performed.

This report is a basic data report for field operations associated with the drilling, logging, completion, and development of South Fence Road Wells SFR-4P and SFR-4T. These test/monitoring wells were installed as part of Sandia National Laboratories, New Mexico, Environmental Restoration Project.

This report is a basic data report fro field operations associated with the drilling, logging, completion, and development of South Fence Road Wells SFR-3P and SFR-3T. These test/monitoring wells were installed as part of Sandia National Laboratories, New Mexico, Environmental Restoration Project.

This report summarizes the work performed to establish calibration traceability for the instrumentation used by Sandia National Laboratories at the Waste Isolation Pilot Plant (WIPP) during testing from 1980-1985. Identifying the calibration traceability is an important part of establishing a pedigree for the data and is part of the qualification of existing data. In general, the requirement states that the calibration of Measuring and Test equipment must have a valid relationship to nationally recognized standards or the basis for the calibration must be documented. Sandia recognized that just establishing calibration traceability would not necessarily mean that all QA requirements were met during the certification of test instrumentation. To address this concern, the assessment was expanded to include various activities.

Sandia National Laboratories' design and development of an optimized Plane Shock Generator Explosive Lens (PSGEL) is detailed in this report. 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 confinement or tamper housing. The purpose of the PSGEL component is to generate a plane shock wave input to a stainless 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 ferro-electric 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. Shock wave planarity data, using an electronic streak camera, are presented for the brass and steel wave separator free surfaces.

The administration of telecommunications is critical to proper maintenance and operation. The intent is to be able to properly support telecommunications for the distribution of all information within a building/campus. This standard will provide a uniform administration scheme that is independent of applications, and will establish guidelines for owners, installers, designers and contractors. This standard will accommodate existing building wiring, new building wiring and outside plant wiring. Existing buildings may not readily adapt to all applications of this standard, but the requirement for telecommunications administration is applicable to all buildings. Administration of the telecommunications infrastructure includes documentation (labels, records, drawings, reports, and work orders) of cables, termination hardware, patching and cross-connect facilities, telecommunications rooms, and other telecommunications spaces (conduits, grounding, and cable pathways are documented by Facilities Engineering). The investment in properly documenting telecommunications is a worthwhile effort. It is necessary to adhere to these standards to ensure quality and efficiency for the operation and maintenance of the telecommunications infrastructure for Sandia National Laboratories.

The important issue of data integrity in the CTBT International Monitoring System (IMS) is discussed and a brief tutorial on data authentication techniques is offered. The utilization of data authentication as a solution to the data integrity problem is evaluated. Public key data authentication is recommended for multilateral monitoring regimes such as the CTBT. The ramifications and system considerations of applying data authentication at various locations in the IMS, or not at all, are reviewed in a data surety context. The paper concludes with a recommendation of authenticating data at all critical monitoring stations.

A nuclear weapons accident is an extremely unlikely event due to the extensive care taken in operations. However, under some hypothetical accident conditions, plutonium might be dispersed to the environment. This would result in costs being incurred by the government to remediate the site and compensate for losses. This study is a multi-disciplinary evaluation of the potential scope of the post-accident response that includes technical factors, current and proposed legal requirements and constraints, as well as social/political factors that could influence decision making. The study provides parameters that can be used to assess economic costs for accidents postulated to occur in urban areas, Midwest farmland, Western rangeland, and forest. Per-area remediation costs have been estimated, using industry-standard methods, for both expedited and extended remediation. Expedited remediation costs have been evaluated for highways, airports, and urban areas. Extended remediation costs have been evaluated for all land uses except highways and airports. The inclusion of cost estimates in risk assessments, together with the conventional estimation of doses and health effects, allows a fuller understanding of the post-accident environment. The insights obtained can be used to minimize economic risks by evaluation of operational and design alternatives, and through development of improved capabilities for accident response.

This report covers the development of fiber optic hydrogen and temperature sensors for monitoring dissolved hydrogen gas in transformer oil. The concentration of hydrogen gas is a measure of the corona and spark discharge within the transformer and reflects the state of health of the transformer. Key features of the instrument include use of palladium alloys to enhance hydrogen sensitivity, a microprocessor controlled instrument with RS-232, liquid crystal readout, and 4-20 ma. current loop interfaces. Calibration data for both sensors can be down loaded to the instrument through the RS-232 interface. This project was supported by the Technology Transfer Initiative in collaboration with J. W. Harley, Inc. through the mechanism of a cooperative research and development agreement (CRADA).

This paper describes an experimental investigation of workpiece surface waviness that stems from poor single point diamond wheel dressing procedures in cylindrical grinding. If done improperly, single point dressing can produce a thread on the grinding wheel surface that is then imposed on the workpiece during machining. The circumferential waviness exhibited by the threaded workpiece is similar to that resulting from one per rev vibrations of the grinding wheel. In order to differentiate between these two sources of waviness, a geometrical approach to predicting the circumferential and axial waves produced during grinding is presented. The concepts presented are illustrated through a series of plunge grinding tests incorporating dressing procedures of varying quality. Test results verify that dressing induced circumferential waviness is similar to waviness resulting from one per rev type vibrations of the grinding wheel. The two sources can be distinguished, however, through examination of the workpiece waviness in the axial direction.

This report summarizes the purchasing and transportation activities of the Procurement Organization for Fiscal Year 1995. Activities for both the New Mexico and California locations are included.

The Risk Management and NEPA (National Environmental Policy Act) Department of Sandia National Laboratories/New Mexico (SNL/NM) recognized the need for hazard and environmental data analysis and management to support the line managers` need to know, understand, manage and document the hazards in their facilities and activities. The Integrated Safety, Environmental, and Emergency Management System (ISEEMS) was developed in response to this need. SNL needed a process that would quickly and easily determine if a facility or project activity contained only standard industrial hazards and therefore require minimal safety documentation, or if non-standard industrial hazards existed which would require more extensive analysis and documentation. Many facilities and project activities at SNL would benefit from the quick screening process used in ISEEMS. In addition, a process was needed that would expedite the NEPA process. ISEEMS takes advantage of the fact that there is some information needed for the NEPA process that is also needed for the safety documentation process. The ISEEMS process enables SNL line organizations to identify and manage hazards and environmental concerns at a level of effort commensurate with the hazards themselves by adopting a necessary and sufficient (graded) approach to compliance. All hazard-related information contained within ISEEMS is location based and can be displayed using on-line maps and building floor plans. This visual representation provides for quick assimilation and analysis.

Mathematical models are presented to predict the bubble pressure for 481 cavern oil samples withdrawn from the Bryan Mound, West Hackberry, Big Hill, and Bayou Choctaw Strategic Petroleum Reserve sites. The predicted bubble point pressure is compared to experimentally measured bubble point pressure to resolve potential sources of error introduced to the experimental analysis. In order to gain a higher level of confidence in the measurement of the bubble point pressure, a stochastic analysis of the data is recommended in the future.

This paper describes a new method for determining, improving, and controlling the measurement process errors (or measurement uncertainty) of a measurement system used to monitor product as it is manufactured. The method is called the Process Measurement Assurance Program (PMAP). It integrates metrology early into the product realization process and is a step beyond statistical process control (SPC), which monitors only the product. In this method, a control standard is used to continuously monitor the status of the measurement system. Analysis of the control standard data allow the determination of the measurement error inherent in the product data and allow one to separate the variability in the manufacturing process from variability in the measurement process. These errors can be then associated with either the measurement equipment, variability of the measurement process, operator bias, or local environmental effects. Another goal of PMAP is to determine appropriate re-calibration intervals for the measurement system, which may be significantly longer or shorter than the interval typically assigned by the calibration organization.

A non-conventional type of heating system is being tested at Sandia National Laboratories for solar thermal power tower applications. In this system, called impedance heating, electric current flows directly through the pipe to maintain the desired temperature. The pipe becomes the resistor where the heat is generated. Impedance heating has many advantages over previously used mineral insulated (MI) heat trace. An impedance heating system should be much more reliable than heat trace cable since delicate junctions and cabling are not used and the main component, a transformer, is inherently reliable. A big advantage of impedance heating is the system can be sized to rapidly heat up the piping to provide rapid response times necessary in cyclic power plants such as solar power towers. In this paper, experimental results from testing an impedance heating system are compared to MI cable heat trace. We found impedance heating was able to heat piping rapidly and effectively. There were not significant stray currents and impedance heating did not affect instrumentation.

Solar Two will be the world`s largest operating solar central receiver power plant. It is expected to begin operating in April 1996; it is currently undergoing start-up and checkout. The plant will use sunlight reflected from 1926 sun-tracking mirrors to heat molten nitrate salt flowing in a heat exchanger (receiver) that sits atop a 200 foot tower. The heated salt will be stored in a tank for use, when needed, to generate superheated steam for producing electricity with a conventional Rankine-cycle turbine/generator. The purpose of the project is to validate molten-salt solar central receiver technology and to reduce the perceived risks associated with the first full-scale commercial plants. Already, much has been learned during the project including the effects of trace contaminants in the salt and the large effect of wind on the receiver. There is also much that remains to be learned. This report describes the technical status of the Solar Two project including a summary of lessons learned to date.

Wind turbines subjected to highly irregular loadings due to wind, gravity, and gyroscopic effects are especially vulnerable to fatigue damage. The objective of this study is to develop and illustrate methods for the probabilistic analysis and design of fatigue-sensitive wind turbine components. A computer program (CYCLES) that estimates fatigue reliability of structural and mechanical components has been developed. A FORM/SORM analysis is used to compute failure probabilities and importance factors of the random variables. The limit state equation includes uncertainty in environmental loading, gross structural response, and local fatigue properties. Several techniques are shown to better study fatigue loads data. Common one-parameter models, such as the Rayleigh and exponential models are shown to produce dramatically different estimates of load distributions and fatigue damage. Improved fits may be achieved with the two-parameter Weibull model. High b values require better modeling of relatively large stress ranges; this is effectively done by matching at least two moments (Weibull) and better by matching still higher moments. For this purpose, a new, four-moment {open_quotes}generalized Weibull{close_quotes} model is introduced. Load and resistance factor design (LRFD) methodology for design against fatigue is proposed and demonstrated using data from two horizontal-axis wind turbines. To estimate fatigue damage, wind turbine blade loads have been represented by their first three statistical moments across a range of wind conditions. Based on the moments {mu}{sub 1}{hor_ellipsis}{mu}{sub 3}, new {open_quotes}quadratic Weibull{close_quotes} load distribution models are introduced. The fatigue reliability is found to be notably affected by the choice of load distribution model.

The objective of this project was to provide an assessment of several methods by which the temperature of a commercial nuclear power plant reactor pressure vessel (RPV) could be measured during an annealing process. This project was a coordinated effort between DOE`s Office of Nuclear Energy, Science and Technology; DOE`s Light Water Reactor Technology Center at Sandia National Laboratories; and the Electric Power Research Institute`s Non- Destructive Evaluation Center. Ball- thermocouple probes similar to those described in NUREG/CR-5760, spring-loaded, metal- sheathed thermocouple probes, and 1778 air- suspended thermocouples were investigated in experiments that heated a section of an RPV wall to simulate a thermal annealing treatment. A parametric study of ball material, emissivity, thermal conductivity, and thermocouple function locations was conducted. Also investigated was a sheathed thermocouple failure mode known as shunting (electrical breakdown of insulation separating the thermocouple wires). Large errors were found between the temperature as measured by the probes and the true RPV wall temperature during heat-up and cool-down. At the annealing soak temperature, in this case 454{degrees}C [850`F], all sensors measured the same temperature within about {plus_minus}5% (23.6{degrees}C [42.5{degrees}F]). Because of these errors, actual RPV wall heating and cooling rates differed from those prescribed (by up to 29%). Shunting does not appear to be a problem under these conditions. The large temperature measurement errors led to the development of a thermal model that predicts the RPV wall temperature from the temperature of a ball- probe. Comparisons between the model and the experimental data for ball-probes indicate that the model could be a useful tool in predicting the actual RPV temperature based on the indicated ball- probe temperature. The model does not predict the temperature as well for the spring-loaded and air suspended probes.

General master equations are used to study steady-state hopping transport in a disordered solid. We express a site`s occupancy in terms of its quasi-electrochemical potential (QECP); currents flow between sites whose QECP`s differ. Coupled nonlinear circuit equations for the QECP`s result from the steady-state condition and the boundary condition that the total QECP drop is the applied emf. When the site-to-site QECP differences are much smaller than the thermal energy, K{sub B}t, the effect of current flow on site occupancies is ignorable. These equations then reduce to those of a resistance network. However, the resistor-network model fails: (a) at low temperatures, (b) with increasing disorder, and (c) with increasing emf. We therefore study hopping conduction beyond this approximation. Exact examples show the importance of current-induced charge redistribution in non-ohmic steady-state flow.

The goal of the Smart Gun Technology project is to eliminate the capability of an unauthorized user form firing a law officer`s firearm by implementing user-recognizing-and-authorizing (or {open_quotes}smart{close_quotes}) surety technologies. This project was funded by the National Institute of Justice. This report lists the findings and results of the project`s three primary objectives. First, to find and document the requirements for a smart firearm technology that law enforcement officers will value. Second, to investigate, evaluate, and prioritize technologies that meet the requirements for a law enforcement officer`s smart firearm. Third, to demonstrate and document the most promising technology`s usefulness in models of a smart firearm.

Evaluation of the long-term performance of the WIPP includes estimation of the cumulative releases of radionuclide elements to the accessible environment. Nonradioactive lead is added because of the large quantity expected in WIPP wastes. To estimate the solubilities of these elements in WIPP brines, the Panel used the following approach. Existing thermodynamic data were used to identify the most likely aqueous species in solution through the construction of aqueous speciation diagrams. Existing thermodynamic data and expert judgment were used to identify potential solubility-limiting solid phases. Thermodynamic data were used to calculate the activities of the radionuclide aqueous species in equilibrium with each solid. Activity coefficients of the radionuclide-bearing aqueous species were estimated using Pitzer`s equations. These activity coefficients were then used to calculate the concentration of each radionuclide at the 0.1 and 0.9 fractiles. The 0.5 fractile was chosen to represent experimental data with activity coefficient corrections as described above. Expert judgment was used to develop the 0.0, 0.25, 0.75, and 1.0 fractiles by considering the sensitivity of solubility to the potential variability in the composition of brine and gas, and the extent of waste contaminants, and extending the probability distributions accordingly. The results were used in the 1991 and 1992 performance assessment calculations. 68 refs.

The construction of a high-assurance system requires some evidence, ideally a proof, that the system as implemented will behave as required. Direct proofs of implementations do not scale up well as systems become more complex and therefore are of limited value. In recent years, refinement-based approaches have been investigated as a means to manage the complexity inherent in the verification process. In a refinement-based approach, a high-level specification is converted into an implementation through a number of refinement steps. The hope is that the proofs of the individual refinement steps will be easier than a direct proof of the implementation. However, if stepwise refinement is performed manually, the number of steps is severely limited, implying that the size of each step is large. If refinement steps are large, then proofs of their correctness will not be much easier than a direct proof of the implementation. The authors describe an approach to refinement-based software development that is based on automatic application of refinements, expressed as program transformations. This automation has the desirable effect that the refinement steps can be extremely small and, thus, easy to prove correct. They give an overview of the TAMPR transformation system that the use for automated refinement. They then focus on some aspects of the semantic framework that they have been developing to enable proofs that TAMPR transformations are correctness preserving. With this framework, proofs of correctness for transformations can be obtained with the assistance of an automated reasoning system.

Shipping containers used for transporting radioactive material must be certified using federal regulations. These regulations require the container be tested or evaluated in severe mechanical and thermal environments which represent hypothetical accident scenarios. The containers are certified if the inner container remains leaktight. This paper presents results from finite element simulations of the accidents which include subjecting the AT-400A (for Pu from dismantled nuclear weapons) to a 30-foot (9 m) drop onto an unyielding target and crushing the container with an 1100 lb (500 kg) steel plate dropped from 30 feet. The nonlinear PRONTO3D finite element results were validated using test results. The simulations of the various impacts and crushes identified trends and worst-case orientations. They also showed that there is a significant margin of safety based on the failure of the containment vessel.

A close-coupled barrier is produced by first installing a conventional cement grout curtain followed by a thin inner lining of a polymer grout. The resultant barrier is a cement polymer composite that has economic benefits derived from the cement and performance benefits from the durable and resistant polymer layer. Close-coupled barrier technology is applicable for final, interim, or emergency containment of subsurface waste forms. Consequently, when considering the diversity of technology application, the construction emplacement and material technology maturity, general site operational requirements, and regulatory compliance incentives, the close-coupled barrier system provides an alternative for any hazardous or mixed waste remediation plan. This paper discusses the installation of a close-coupled barrier and the subsequent integrity verification. The demonstration was installed at a benign site at the Hanford Geotechnical Test Facility, 400 Area, Hanford, Washington. The composite barrier was emplaced beneath a 7,500 liter tank. The tank was chosen to simulate a typical DOE Complex waste form. The stresses induced on the waste form were evaluated during barrier construction. The barrier was constructed using conventional jet grouting techniques. Drilling was completed at a 45{degree} angle to the ground, forming a conical shaped barrier with the waste form inside the cone. Two overlapping rows of cylindrical cement columns were grouted in a honeycomb fashion to form the secondary backdrop barrier layer. The primary barrier, a high molecular weight polymer manufactured by 3M Company, was then installed providing a relatively thin inner liner for the secondary barrier. The primary barrier was emplaced by panel jet grouting with a dual wall drill stem, two phase jet grouting system.

No abstract available.

Diamond switches are well suited for use in high temperature electronics. Laboratory feasibility of diamond switching at 1 kV and 18 A was demonstrated. DC blocking voltages up to 1 kV were demonstrated. A 50 {Omega} load line was switched using a diamond switch, with switch on-state resistivity {approx}7 {Omega}-cm. An electron beam, {approx}150 keV energy, {approx}2 {mu}s full width at half maximum was used to control the 5 mm x 5 mm x 100 {mu}m thick diamond switch. The conduction current temporal history mimics that of the electron beam. These data were taken at room temperature.

The use of native oxides (selective oxidation) in vertical cavity surface emitting lasers has produced dramatic improvements in these laser diodes but has also been suspected of causing poor reliability because of incidental reports of short lifetimes and physical considerations. Here we discuss the results of thousands of hours life-tests for oxide confined and implant confined devices at current densities from 1 to 12 kA/cmr. There was a single infant mortality failure from a sample of 14 oxide confined lasers with the remainder showing relatively stable operation. The failed device is analyzed in terms of light current characteristics and near-field electroluminescence images, and potential screening criteria are proposed.

As part of the Environmentally Conscious Manufacturing (ECM) technology, and in support of various mechanical assembly applications, several aqueous alkaline cleaners were studied as potential candidates for cleaning mechanical piece parts. Historically, ozone depleting and hazardous chlorinated cleaners have been used to degrease mechanical assemblies. In an effort to replace these chemicals, several cleaning processes, including aqueous alkaline cleaners, were screened as potential candidates using a variety of criteria, including aqueous alkaline cleaners, were screened as potential candidates using a variety of criteria, including: cleaning efficiency, materials compatibility, etch rate, corrosion, immersion tests, temperature/humidity exposure, and an exposure to a simulated indoor industrial environment. Cleaning efficiency was determined using visual examination, Auger electron spectroscopy, X-ray photoelectron spectroscopy, MESERAN, and goniometer/contact angle measurements. Several cleaners were identified as potential alternatives based solely on the cleaning results. Some of the cleaners, however, left undesirable residues. This paper will focus on materials compatibility issues of these aqueous cleaners after immersion tests, an etch rate study, and exposures to temperature/humidity and a standard industrial environment.

The purpose of hazardous and radioactive materials packaging is to enable these materials to be transported without posing a threat to the health or property of the general public. To achieve this aim, regulations in the US have been written establishing general design requirements for such packagings. While no regulations have been written specifically for mixed waste packaging, regulations for the constituents of mixed wastes, i.e., hazardous and radioactive substances, have been codified by the US Department of Transportation (US DOT, 49 CFR 173) and the US Nuclear Regulatory Commission (NRC, 10 CFR 71). Based on these national requirements, a Chemical Compatibility Testing Program was developed in the Transportation Systems Department at Sandia National Laboratories (SNL). The program provides a basis to assure any regulatory body that the issue of packaging material compatibility towards hazardous and radioactive materials has been addressed. In this paper, the authors present the results of the second phase of this testing program. The first phase screened five liner materials and six seal materials towards four simulant mixed wastes. This phase involved the comprehensive testing of five candidate liner materials to an aqueous Hanford Tank simulant mixed waste. The comprehensive testing protocol involved exposing the respective materials a matrix of four gamma radiation doses ({approximately} 1, 3, 6, and 40 kGy), three temperatures (18, 50, and 60 C), and four exposure times (7, 14, 28, and 180 days). Following their exposure to these combinations of conditions, the materials were evaluated by measuring five material properties. These properties were specific gravity, dimensional changes, hardness, stress cracking, and mechanical properties.

Sandia National Laboratories is nearing the completion of the initial development of a unique type of range imaging sensor. This innovative imaging optical radar is based on an active flood-light scene illuminator and an image intensified CCD camera receiver. It is an all solid-state device (no moving parts) and offers significant size, performance, reliability, simplicity, and affordability advantages over other types of 3-D sensor technologies, including: scanned laser radar, stereo vision, and structured lighting. The sensor is based on low cost, commercially available hardware, and is very well suited for affordable application to a wide variety of military and commercial uses, including: munition guidance, target recognition, robotic vision, automated inspection, driver enhanced vision, collision avoidance, site security and monitoring, terrain mapping, and facility surveying. This paper reviews the sensor technology and its development for the advanced conventional munition guidance application, and discusses a few of the many other emerging applications for this new innovative sensor technology.

The electrical properties of the light ion impurities H, O and C in GaN have been examined in both as-grown and implanted material. H is found to efficiently passivate acceptors such as Mg, Ca and C. Reactivation occurs at {ge} 450 C and is enhanced by minority carrier injection. The hydrogen does not leave the GaN crystal until > 800 C, and its diffusivity is relatively high ({approximately} 10{sup {minus}11} cm{sup 2}/s) even at low temperatures (< 200 C) during injection by wet etching, boiling in water or plasma exposure. Oxygen shows a low donor activation efficiency when implanted into GaN, with an ionization level of 30--40 meV. It is essentially immobile up to 1,100 C. Carbon can produce low p-type levels (3 {times} 10{sup 17} cm{sup {minus}3}) in GaN during MOMBE, although there is some evidence it may also create n-type conduction in other nitrides.

Etch rates up to 7,000 {angstrom}/min. for GaN are obtained in Cl{sub 2}/H{sub 2}/Ar or BCl{sub 3}/Ar ECR discharges at 1--3mTorr and moderate dc biases. Typical rates with HI/H{sub 2} are about a factor of three lower under the same conditions, while CH{sub 4}/H{sub 2} produces maximum rates of only {approximately}2,000 {angstrom}/min. The role of additives such as SF{sub 6}, N{sub 2}, H{sub 2} or Ar to the basic chlorine, bromine, iodine or methane-hydrogen plasma chemistries are discussed. Their effect can be either chemical (in forming volatile products with N) or physical (in breaking bonds or enhancing desorption of the etch products). The nitrides differ from conventional III-V`s in that bond-breaking to allow formation of the etch products is a critical factor. Threshold ion energies for the onset of etching of GaN, InGaN and InAlN are {ge} 75 eV.

The NCMS PWB Surface Finishes Consortium is just about at the end of the five year program. Dozens of projects related to surface finishes and PWB solder-ability were performed by the team throughout the program, and many of them are listed in this paper. They are listed with a cross reference to where and when a technical paper was presented describing the results of the research. However, due to time and space constraints, this paper can summarize the details of only three of the major research projects accomplished by the team. The first project described is an ``Evaluation of PWB Surface Finishes.`` It describes the solderability, reliability, and wire bondability of numerous surface finishes. The second project outlined is an ``Evaluation of PWB Solderability Test Methods.`` The third project outlined is the ``Development and Evaluation of Organic Solderability Preservatives.``

The Advanced Networking Integration Department at Sandia National Laboratories has used the annual Supercomputing conference sponsored by the IEEE and ACM for the past three years as a forum to demonstrate and focus communication and networking developments. For Supercomputing `95, Sandia elected: to demonstrate the functionality and capability of an AT&T Globeview 20Gbps Asynchronous Transfer Mode (ATM) switch, which represents the core of Sandia`s corporate network, to build and utilize a three node 622 megabit per second Paragon network, and to extend the DOD`s ACTS ATM Internet from Sandia, New Mexico to the conference`s show floor in San Diego, California, for video demonstrations. This paper documents those accomplishments, discusses the details of their implementation, and describes how these demonstrations supports Sandia`s overall strategies in ATM networking.

The development of on-line engineering textbooks presents new challenges to authors to effectively integrate text and tools in an electronic environment. By incorporating human factors principles of interface design and cognitive psychology early in the design process, a team at Sandia National Laboratories was able to make the end product more usable and shorten the prototyping and editing phases. A critical issue was simultaneous development of paper and on-line versions of the textbook. In addition, interface consistency presented difficulties with distinct goals and limitations for each media. Many of these problems were resolved swiftly with human factors input using templates, style guides and iterative usability testing of both paper and on-line versions. Writing style continuity was also problematic with numerous authors contributing to the text.

The ability to use an interactive world model, whether it is for robotics simulation or most other virtual graphical environments, relies on the users ability to create an accurate world model. Typically this is a tedious process, requiring many hours to create 3-D CAD models of the surfaces within a workspace. The goal of this ongoing project is to develop usable methods to rapidly build world models of real world workspaces. This brings structure to an unstructured environment and allows graphical based robotics control to be accomplished in a reasonable time frame when traditional CAD modelling is not enough. To accomplish this, 3D range sensors are deployed to capture surface data within the workspace. This data is then transformed into surface maps, or models. A 3D world model of the workspace is built quickly and accurately, without ever having to put people in the environment.

The efficiency of converting chemical energy into electrical energy has been studied for the case of D-size, low and medium rate lithium-thionyl chloride (Li/TC) cells, under DC and various pulsed loads. Microcalorimetric monitoring of the heat output during discharge allowed the direct measurement of the faradaic efficiency, and showed that self-discharge is far more pervasive than previously acknowledged by researchers and battery manufacturers. Evaluations of the cell dynamics prove that current load and temperature fluctuations combine to disrupt the lithium passivation and to greatly enhance self-discharge. Typical faradaic efficiencies for DC range from abut 30% at low current density to 90% at moderate and 75% at high current density. Pulsed current further depresses these efficiency levels, except at very low average current densities. The decreased faradaic efficiency of Li/TC batteries in certain pulse situations needs to be studied further to define the range of applications for which it can be successfully used.

Short communication.

TAMPR is a fully automatic transformation system based on syntactic rewrites. Our approach in a correctness proof is to map the transformation into an axiomatized mathematical domain where formal (and automated) reasoning can be performed. This mapping is accomplished via an extended denotational semantic paradigm. In this approach, the abstract notion of a program state is distributed between an environment function and a store function. Such a distribution introduces properties that go beyond the abstract state that is being modeled. The reasoning framework needs to be aware of these properties in order to successfully complete a correctness proof. This paper discusses some of our experiences in proving the correctness of TAMPR transformations.

The use of modular systems to distribute power using batteries to store off-peak energy and a state of the art power inverter is envisioned to offer important national benefits. A 4-year, cost- shared contract was performed to design and develop a modular, 300kVA/300-kWh system for utility and customer applications. Called Nas-P{sub AC}, this system uses advanced sodium/sulfur batteries and requires only about 20% of the space of a lead-acid-based system with a smaller energy content. Ten, 300-VDC, 40-kWh sodium/sulfur battery packs are accommodated behind a power conversion system envelope with integrated digital control. The resulting design facilities transportation, site selection, and deployment because the system is quiet and non-polluting, and can be located in proximity to the load. This report contains a detailed description of the design and supporting hardware development performed under this contract.

The environmentally safe destruction of pinkwater is a significant problem that requires a multidisciplinary approach to solve. We have investigated the application of advanced oxidation processes, including the use of both UV light source and laser technologies. The reactions were run under both oxidizing and reducing atmospheres. Aerobic and anaerobic biotreatments were examined as both pre- and post-treatments to the oxidation processes. The toxicity of the wastewater at various stages of treatment was determined. Membrane preconcentration schemes were examined to determine their effectiveness as part of the total pinkwater treatment scheme.

The proposed action for this EA for Sandia National Laboratories/New Mexico Technical Area IV, includes continuing existing operations, modification of an existing accelerator (Particle Beam Fusion Accelerator II) to support defnese-related Z-pinch experiments, and construction of two transformer oil storage tanks to support the expansion of the Advanced Pulsed Power Research Module, a single pulse accelerator. Based on the analyses in the EA, DOE believes that the proposed action is not a major federal action significantly affecting the quality of the human environment within the meaning of NEPA and CEQ NEPA implementing regulations in 40 CFR 1508.18 and 1508.27. Therefore, an environmental impact statement is not required, and a Finding of No Significant Impact is issued.

This report discusses an evaluation of intrusion sensors and video assessment in areas of restricted passage. The discussion focuses on applications of sensors and video assessment in suspended ceilings and air ducts. It also includes current and proposed requirements for intrusion detection and assessment. Detection and nuisance alarm characteristics of selected sensors as well as assessment capabilities of low-cost board cameras were included in the evaluation.

One thing that all access control applications have in common is the need to identify those individuals authorized to gain access to an area. Traditionally, the identification is based on something that person possesses, such as a key or badge, or something they know, such as a PIN or password. Biometric identifiers make their decisions based on the physiological or behavioral characteristics of individuals. The potential of biometrics devices to positively identify individuals has made them attractive for use in access control and computer security applications. However, no systems perform perfectly, so it is important to understand what a biometric device`s performance is under real world conditions before deciding to implement one in an access control system. This paper will describe the evaluation of a prototype biometric identifier provided by IriScan Incorporated. This identifier was developed to recognize individual human beings based on the distinctive visual characteristics of the irises of their eyes. The main goal of the evaluation was to determine whether the system has potential as an access control device within the Department of Energy (DOE). The primary interest was an estimate of the accuracy of the system in terms of false accept and false reject rates. Data was also collected to estimate throughput time and user acceptability. The performance of the system during the test will be discussed. Lessons learned during the test which may aid in further testing and simplify implementation of a production system will also be discussed.

Multi-kilowatt Nd:YAG lasers provide an appealing solution for aluminum laser welding applications due to increased bulk absorption and ease of beam delivery as compared to high power CO{sub 2} laser systems. However, high numerical aperture optics are required to overcome the relatively poor beam quality associated with these lasers and to achieve a high irradiance. Several lens designs have been developed and evaluated to achieve the high irradiance values required to provide good coupling into aluminum alloys. The results of these tests demonstrate that near diffraction limited performance can be achieved for high numerical aperture elements. Additionally, an inverse-telephoto lens design has been developed and characterized to further demonstrate the feasibility of producing a high irradiance with a functional working distance from the weld surface.

Scientific computing centers are acquiring large, distributed memory machines. With memory systems of .25 to 2.5 terabytes, these machines will deliver 1-10 teraflop computing capabilities. The need to move 10`s or 100`s of gigabytes, and the need to provide petabyte storage systems are issues that must be addressed before the year 2000. Work currently underway at Sandia addresses these issues. The High Performance Storage System (HPSS) is in limited production and the mass storage environment to support Sandia`s teraflop computer system is being constructed. 26 refs., 5 figs.

The Waste Isolation Pilot Plant (WIPP) is located 660 m underground in the Salado Formation which consists of thick, horizontally bedded pure and impure salt and thin, laterally continuous clay and anhydrite interbeds. The Salado Two-Phase Flow Laboratory Program was established to provide site-specific-two-phase flow and other related rock properties to support performance assessment modeling of the WIPP repository. Owing to their potentially significant role in the hydrologic response of the repository, the program initially focused on the anhydrite interbeds, and in particular, on Marker Bed 139 (MB 139), which lies approximately 1 m below the planned waste storage rooms. This report synthesizes petrographic and X-ray powder diffraction studies performed to support the Salado Two-Phase Flow Laboratory Program. Experimental scoping activities in this area were performed in FY 1993 by three independent laboratories in order to: (1) quantify the mineral composition to support laboratory studies of hydrologic properties and facilitate correlation of transport properties with composition; (2) describe textures, including grain size; and (3) describe observed porosity. Samples from various depths were prepared from six 6-inch diameter cores which were obtained by drilling into the marker bed from the floor of two separate rooms. The petrographic analyses are augmented here with additional study of the original thin sections, and the pore structure observations are also examined in relation to an independent observational study of microcracks in Marker Bed 139 core samples performed in FY 1994 by the Geomechanics Department at Sandia National Laboratories.

Stratigraphic units of the Salado Formation at the Waste Isolation Pilot Plant (WIPP) disposal room horizon includes various layers of halite, polyhalitic halite, argillaceous halite, clay, and anhydrite. Current models, including those used in the WIPP Performance Assessment calculations, employ a ``composite stratigraphy`` approach in modeling. This study was initiated to evaluate the impact that an explicit representation of detailed stratigraphy around the repository may have on fluid flow compared to the simplified ``composite stratigraphy`` models currently employed. Sensitivity of model results to intrinsic permeability anisotropy, interbed fracturing, two-phase characteristic curves, and gas-generation rates were studied. The results of this study indicate that explicit representation of the stratigraphy maintains higher pressures and does not allow as much fluid to leave the disposal room as compared to the ``composite stratigraphy`` approach. However, the differences are relatively small. Gas migration distances are also different between the two approaches. However, for the two cases in which explicit layering results were considerably different than the composite model (anisotropic and vapor-limited), the gas-migration distances for both models were negligible. For the cases in which gas migration distances were considerable, van Genuchten/Parker and interbed fracture, the differences between the two models were fairly insignificant. Overall, this study suggests that explicit representation of the stratigraphy in the WIPP PA models is not required for the parameter variations modeled if ``global quantities`` (e.g., disposal room pressures, net brine and gas flux into and out of disposal rooms) are the only concern.

Within the DOE complex there exists a tremendous quantity of radioactive scrap metal. As an example, it is estimated that within the gaseous diffusion plants there exists in excess of 700,000 tons of contaminated stainless steel. At present, valuable material is being disposed of when it could be converted into a high quality product. Liquid metal processing represents a true recycling opportunity for this material. By applying the primary production processes towards the material`s decontamination and re-use, the value of the strategic resource is maintained while drastically reducing the volume of material in need of burial. Potential processes for the liquid metal decontamination of radioactively contaminated metal are discussed and contrasted. Opportunities and technology development issues are identified and discussed. The processes compared are: surface decontamination; size reduction, packaging and burial; melting technologies; electric arc melting; plasma arc centrifugal treatment; air induction melting; vacuum induction melting; and vacuum induction melting and electroslag remelting.

A systems prioritization methodology (SPM) is under development to provide guidance to the US DOE on experimental programs and design modifications to be supported in the development of a successful licensing application for the Waste Isolation Pilot Plant (WIPP) for the geologic disposal of transuranic (TRU) waste. The purpose of the SPM is to determine the probabilities that the implementation of different combinations of experimental programs and design modifications, referred to as activity sets, will lead to compliance. Appropriate tradeoffs between compliance probability, implementation cost and implementation time can then be made in the selection of the activity set to be supported in the development of a licensing application. Descriptions are given for the conceptual structure of the SPM and the manner in which this structure determines the computational implementation of an example SPM application. Due to the sophisticated structure of the SPM and the computational demands of many of its components, the overall computational structure must be organized carefully to provide the compliance probabilities for the large number of activity sets under consideration at an acceptable computational cost. Conceptually, the determination of each compliance probability is equivalent to a large numerical integration problem. 96 refs., 31 figs., 36 tabs.

This paper presents data from an instantaneous profile test conducted near the Sandia National Laboratories/New Mexico Mixed Waste Landfill in Technical Area 3. The test was performed from December 1993 through 1995 as part of the environmental Restoration Project`s Phase 2 RCRA Facility Investigation of the Mixed Waste Landfill. The purpose of the test was to measure the unsaturated hydraulic properties of soils near the Mixed Waste Landfill. The instantaneous profile test and instrumentation are described, and the pressure and moisture content data from the test are presented. These data may be useful for understanding the unsaturated hydraulic properties of soils in Technical Area 3 and for model validation, verification, and calibration.

Adaptive sampling programs provide real opportunities to save considerable time and money when characterizing hazardous waste sites. This Strategic Environmental Research and Development Program (SERDP) project demonstrated two decision-support technologies, SitePlanner{trademark} and Plume{trademark}, that can facilitate the design and deployment of an adaptive sampling program. A demonstration took place at Joliet Army Ammunition Plant (JAAP), and was unique in that it was tightly coupled with ongoing Army characterization work at the facility, with close scrutiny by both state and federal regulators. The demonstration was conducted in partnership with the Army Environmental Center`s (AEC) Installation Restoration Program and AEC`s Technology Development Program. AEC supported researchers from Tufts University who demonstrated innovative field analytical techniques for the analysis of TNT and DNT. SitePlanner{trademark} is an object-oriented database specifically designed for site characterization that provides an effective way to compile, integrate, manage and display site characterization data as it is being generated. Plume{trademark} uses a combination of Bayesian analysis and geostatistics to provide technical staff with the ability to quantitatively merge soft and hard information for an estimate of the extent of contamination. Plume{trademark} provides an estimate of contamination extent, measures the uncertainty associated with the estimate, determines the value of additional sampling, and locates additional samples so that their value is maximized.

The Uranium Mill Tailings Remediation Action (UMTRA) Project is responsible for the assessment and remedial action at the 24 former uranium mill tailings sites located in the US. The surface restoration phase, which includes containment and stabilization of the abandoned uranium mill tailings piles, has a specific termination date and is nearing completion. Therefore, attention has now turned to the groundwater restoration phase, which began in 1991. Regulated constituents in groundwater whose concentrations or activities exceed maximum contaminant levels (MCLs) or background levels at one or more sites include, but are not limited to, uranium, selenium, arsenic, molybdenum, nitrate, gross alpha, radium-226 and radium-228. The purpose of this report is to recommend computer codes that can be used to assist the UMTRA groundwater restoration effort. The report includes a survey of applicable codes in each of the following areas: (1) groundwater flow and contaminant transport modeling codes, (2) hydrogeochemical modeling codes, (3) pump and treat optimization codes, and (4) decision support tools. Following the survey of the applicable codes, specific codes that can best meet the needs of the UMTRA groundwater restoration program in each of the four areas are recommended.

A new family of microminiature sensors and clocks is being developed with widespread application potential for missile and weapons applications, as biomedical sensors, as vehicle status monitors, and as high-volume animal identification and health sensors. To satisfy fundamental technology development needs, a micromachined clock and an accelerometer have initially been undertaken as development projects. A thickness-mode quartz resonator housed in a micromachined silicon package is used as the frequency-modulated basic component of the sensor family. Resonator design philosophy follows trapped energy principles and temperature compensation methodology through crystal orientation control, with operation in the 20--100 MHz range, corresponding to quartz wafer thicknesses in the 75--15 micron range. High-volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Chemical etching of quartz, as well as micromachining of silicon, achieves the surface and volume mechanical features necessary to fashion the resonating element and the mating package. Integration of the associated oscillator and signal analysis circuitry into the silicon package is inherent to the realization of a size reduction requirement. A low temperature In and In/Sn bonding technology allows assembly of the dissimilar quartz and silicon materials, an otherwise challenging task. Unique design features include robust vibration and shock performance, capacitance sensing with micromachined diaphragms, circuit integration, capacitance-to-frequency transduction, and extremely small dimensioning. Accelerometer sensitivities were measured in the 1--3 ppm/g range for the milligram proof-mass structures employed in the prototypes evaluated to date.