Publications

Over the last fifteen years, Sandia National Laboratories Security Systems and Technology Center, Department 5800, has been involved in several laboratory tests of various biometric identification devices. These laboratory tests were conducted to verify the manufacturer`s performance claims, to determine strengths and weaknesses of particular devices, and to evaluate which devices meet the US Department of Energy`s unique needs for high-security devices. However, during a recent field installation of one of these devices, significantly different performance was observed than had been predicted by these laboratory tests. This report documents the data analysis performed in the search for an explanation of these differences.

The monolithic integration of micromechanical devices with their controlling electronics offers potential increases in performance as well as decreased cost for these devices. Analog Devices has demonstrated the commercial viability of this integration by interleaving micromechanical fabrication steps with microelectronic fabrication steps to produce a single-axis accelerometer on a chip. A next-generation integrated technology developed at Sandia National Laboratories eliminates many of the constraints associated with Analog`s process. This new technology enables the manufacture of complex micromachined sensor systems on a chip. An overview of Sandia`s micromachined system-on-a-chip technology along with application of the technology to inertial sensor systems designed by researchers at U.C. Berkeley will be given.

The fundamental goal of this research has been to improve computational efficiency of the Visually Empirical Region of Influence (VERI) based clustering and pattern recognition (PR) algorithms we developed in previous work. The original clustering algorithm, when applied to data sets with N points, ran in time proportional to N{sup 3} (denoted with the notation O (N{sup 3})), which limited the size of data sets it could find solutions for. Results generated from our original clustering algorithm were superior to commercial clustering packages. These results warranted our efforts to improve the runtimes of our algorithms. This report describes the new algorithms, advances and obstacles met in their development. The report gives qualitative and quantitative analysis of the improved algorithms performances. With the information in this report, an interested user can determine which algorithm is best for a given problem in clustering (2-D) or PR (K-D), and can estimate how long it will run using the runtime plots of the algorithms before using any software.

Cooperative monitoring systems can play an important part in promoting the implementation of regional cooperative security agreements. These agreements advance the national security interests of the United States in a post Cold War environment. Regional issues as widely varying as nuclear nonproliferation, trade and environmental pollution can be the source of tensions which may escalate to armed conflict which could have global implications. The Office of National Security Policy Analysis at the US Department of Energy (DOE) has an interest in seeking ways to promote regional cooperation that can reduce the threats posed by regional conflict. DOE technologies and technical expertise can contribute to developing solutions to a wide variety of these international problems. Much of this DOE expertise has been developed in support of the US nuclear weapons and arms control missions. It is now being made available to other agencies and foreign governments in their search for regional security and cooperation. This report presents two examples of interest to DOE in which monitoring technologies could be employed to promote cooperation through experimentation. The two scenarios include nuclear transparency in Northeast Asia and environmental restoration in the Black Sea. Both offer the potential for the use of technology to promote regional cooperation. The issues associated with both of these monitoring applications are presented along with examples of appropriate monitoring technologies, potential experiments and potential DOE contributions to the scenarios.

Interferometric Synthetic Aperture Radar (IFSAR) is a very promising technology for remote mapping of 3-Dimensional objects. In particular, 3-D maps of urban areas are extremely important to a wide variety of users, both civilian and military. However, 3-D maps produced by traditional optical stereo (stereogrammetry) techniques can be quite expensive to obtain, and accurate urban maps can only be obtained with a large amount of human-intensive interpretation work. IFSAR has evolved over the last decade as a mapping technology that promises to eliminate much of the human-intensive work in producing elevation maps. However, IFSAR systems have only been robustly demonstrated in non-urban areas, and have not traditionally been able to produce data with enough detail to be of general use in urban areas. Sandia Laboratories Twin Otter IFSAR was the first mapping radar system with the proper parameter set to provide sufficiently detailed information in a large number of urban areas. The goal of this LDRD was to fuse previously unused information derived from IFSAR data in urban areas that can be used to extract accurate digital elevation models (DEMs) over wide areas without intensive human interaction.

This report contains the results of a Sandia National Laboratories Directed Research and Development (LDRD) program to investigate the integration of Global Positioning System (GPS) and inertial navigation system (INS) technologies toward the goal of optimizing the navigational accuracy of the combined GPSANS system. The approach undertaken is to integrate the data from an INS, which has long term drifts, but excellent short term accuracy, with GPS carrier phase signal information, which is accurate to the sub-centimeter level, but requires continuous tracking of the GPS signals. The goal is to maintain a sub-meter accurate navigation solution while the vehicle is in motion by using the GPS measurements to estimate the INS navigation errors and then using the refined INS data to aid the GPS carrier phase cycle slip detection and correction and bridge dropouts in the GPS data. The work was expanded to look at GPS-based attitude determination, using multiple GPS receivers and antennas on a single platform, as a possible navigation aid. Efforts included not only the development of data processing algorithms and software, but also the collection and analysis of GPS and INS flight data aboard a Twin Otter aircraft. Finally, the application of improved navigation system accuracy to synthetic aperture radar (SAR) target location is examined.

Gas generation from the microbial degradation of the organic constituents of transuranic waste under conditions expected at the Waste Isolation Pilot Plant (WIPP) repository was investigated at Brookhaven National Laboratory. The biodegradation of mixed cellulosics (various types of paper) and electron-beam irradiated plastic and rubber materials (polyethylene, polyvinylchloride, neoprene, hypalon, and leaded hypalon) was examined. The rate of gas production from cellulose biodegradation in inundated samples incubated for 1,228 days at 30 C was biphasic, with an initial rapid rate up to approximately 600 days incubation, followed by a slower rate. The rate of total gas production in anaerobic samples containing mixed inoculum was as follows: 0.002 mL/g cellulose/day without nutrients; 0.004 mL/g cellulose/day with nutrients; and 0.01 mL/g cellulose/day in the presence of excess nitrate. Carbon dioxide production proceeded at a rate of 0.009 {micro}mol/g cellulose/day in anaerobic samples without nutrients, 0.05 {micro}mol/g cellulose/day in the presence of nutrients, and 0.2 {micro}mol/g cellulose/day with excess nitrate. Adding nutrients and excess nitrate stimulated denitrification, as evidenced by the accumulation of N{sub 2}O in the headspace (200 {micro}mol/g cellulose). The addition of the potential backfill bentonite increased the rate of CO{sub 2} production to 0.3 {micro}mol/g cellulose/day in anaerobic samples with excess nitrate. Analysis of the solution showed that lactic, acetic, propionic, butyric, and valeric acids were produced due to cellulose degradation. Samples incubated under anaerobic humid conditions for 415 days produced CO{sub 2} at a rate of 0.2 {micro}mol/g cellulose/day in the absence of nutrients, and 1 {micro}mol/g cellulose/day in the presence of bentonite and nutrients. There was no evidence of biodegradation of electron-beam irradiated plastic and rubber.

This report describes a Strategic Environmental Research and Development Program (SERDP) project to field a dish/Stirling system at a southwestern US military facility. This project entitled ``Dish/Stirling for DoD Applications`` was started in August 1993 and was completed in September 1996. The project`s objective was to assist military facilities to field and evaluate emerging environmentally sound and potentially economical dish/Stirling technology. Dish/Stirling technology has the potential to produce electricity at competitive costs while at the same time providing a secure and environmentally benign source of power. In accordance with the SERDP charter, this project leveraged a US Department of Energy (DOE) cost-shared project between Sandia National Laboratories and Cummins Power Generation, Inc. (CPG). CPG is a wholly owned subsidiary of Cummins Engine Company, a leading manufacturer of diesel engines. To accomplish this objective, the project called for the installation of a dish/Stirling system at a military facility to establish first-hand experience in the operation of a dish/Stirling system. To scope the potential DoD market for dish/Stirling technology and to identify the site for the demonstration, a survey of southwestern US military facilities was also conducted. This report describes the project history, the Cummins dish/Stirling system, results from the military market survey, and the field test results.

Nuclear weapons have been produced in the US since the early 1950s by a network of contractor-operated Department of Energy (DOE) facilities collectively known as the Nuclear Weapon Complex (NWC). Recognizing that the failure of an essential process might stop weapon production for a substantial period of time, the DOE Albuquerque Operations office initiated the Production Risk Evaluation Program (PREP) at Sandia National Laboratories (SNL) to assess quantitatively the potential for serious disruptions in the NWC weapon production process. PREP was conducted from 1984-89. This document is an unclassified summary of the effort.

This report summarizes tests on five different foams. Two are manufactured at Allied Signal, two at North Carolina Foam Industries, and one at General Plastics. The tests conducted are: thermal conductivity at various temperatures, specific heat at 60{degrees}C, compressive strength at ambient and 60{degrees}C, thermogravimetric analysis to 800{degrees}C, intumescence, and char formation properties. A CHN analysis was also performed. Funding for the testing of rigid polyurethane foams originated from the AT-400A container program at Sandia National Laboratories. This testing supported the development of the AT-400A container. The AT-400A is a storage and transportation container that will be used initially at the Pantex Plant for storage of plutonium from dismantled nuclear weapons.

This paper describes results from efforts to develop VOC sensing systems based on two complementary techniques. The first technique used a gated channeltron detector for resonant laser-induced multiphoton photoionization detection of trace organic vapors in a supersonic molecular beam. The channeltron was gated using a relatively simple circuit to generate a negative gate pulse with a width of 400 ns (FWHM), a 50 ns turn-on (rise) time, a 1.5 {mu}s turn-off (decay) time, a pulse amplitude of {minus}1000 Volts, and a DC offset adjustable from zero to {minus}1500 Volts. The gated channeltron allows rejection of spurious responses to UV laser light scattered directly into the channeltron and time-delayed ionization signals induced by photoionization of residual gas in the vacuum chamber. Detection limits in the part-per-trillion range have been demonstrated with the gated detector. The second technique used arrays of surface acoustic wave (SAW) devices coated with various chemically selective materials (e.g., polymers, self assembled monolayers) to provide unique response patterns to various chemical analytes. This work focused on polymers, formed by spin casting from solution or by plasma polymerization, as well as on self assembled monolayers. Response from coated SAWs to various concentrations of water, volatile organics, and organophosphonates (chemical warfare agent simulants) were used to provide calibration data. A novel visual empirical region of influence (VIERI) pattern recognition technique was used to evaluate the ability to use these response patterns to correctly identify chemical species. This investigation shows how the VERI technique can be used to determine the best set of coatings for an array, to predict the performance of the array even if sensor responses change due to aging of the coating materials, and to identify unknown analytes based on previous calibration data.

Paving is an automated mesh generation algorithm which produces all-quadrilateral elements. It can additionally generate these elements in varying sizes such that the resulting mesh adapts to a function distribution, such as an error function. While powerful, conventional paving is a very serial algorithm in its operation. Parallel paving is the extension of serial paving into parallel environments to perform the same meshing functions as conventional paving only on distributed, discretized models. This extension allows large, adaptive, parallel finite element simulations to take advantage of paving`s meshing capabilities for h-remap remeshing. A significantly modified version of the CUBIT mesh generation code has been developed to host the parallel paving algorithm and demonstrate its capabilities on both two dimensional and three dimensional surface geometries and compare the resulting parallel produced meshes to conventionally paved meshes for mesh quality and algorithm performance. Sandia`s {open_quotes}tiling{close_quotes} dynamic load balancing code has also been extended to work with the paving algorithm to retain parallel efficiency as subdomains undergo iterative mesh refinement.

Advanced reactor systems are likely to use protection systems with digital electronics that ideally should be resistant to environmental hazards, including smoke from possible cable fires. Previous smoke tests have shown that digital safety systems can fail even at relatively low levels of smoke density and that short-term failures are likely to be caused by circuit bridging. Experiments were performed to examine these failures, with a focus on component packaging and protection schemes. Circuit bridging, which causes increased leakage currents and arcs, was gauged by measuring leakage currents among the leads of component packages. The resistance among circuit leads typically varies over a wide range, depending on the nature of the circuitry between the pins, bias conditions, circuit board material, etc. Resistance between leads can be as low as 20 k{Omega} and still be good, depending on the component. For these tests, the authors chose a printed circuit board and components that normally have an interlead resistance above 10{sup 12} {Omega}, but if the circuit is exposed to smoke, circuit bridging causes the resistance to fall below 10{sup 3} {Omega}. Plated-through-hole (PTH) and surface-mounted (SMT) packages were exposed to a series of different smoke environments using a mixture of environmentally qualified cables for fuel. Conformal coatings and enclosures were tested as circuit protection methods. High fuel levels, high humidity, and high flaming burns were the conditions most likely to cause circuit bridging. The inexpensive conformal coating that was tested - an acrylic spray - reduced leakage currents, but enclosure in a chassis with a fan did not. PTH packages were more resistant to smoke-induced circuit bridging than SMT packages. Active components failed most often in tests where the leakage currents were high, but failure did not always accompany high leakage currents.

The thermo-hydrologic behavior of the potential repository at Yucca Mountain, Nevada, has been simulated to investigate the effects of infiltration. Transient temperatures, liquid saturations, and liquid mass flow rates through the fractures and matrix were simulated using several different steady infiltration rates ranging from 0.3 to 30 min./year. The lower infiltration rates resulted in higher temperatures near the repository element, but the overall transient temperature profiles were similar. The hydrologic response near the repository (liquid saturations and fluxes) was found to be very sensitive to the infiltration rate. Increased infiltration rates reduced the time to re-wet the simulated repository during cooling, and an infiltration rate of 10 mm/year was sufficient to completely eliminate the dry-out zone around the repository.

In March 1994, the US Department of Energy Carlsbad Area Office (DOE/CAO) implemented a performance based decision-aiding method to assist in programmatic prioritization within the Waste Isolation Pilot Plant (WIPP) project. The prioritization was with respect to 40 CFR Part 191.13(a) and 40 CFR part 268.6. U.S. Environmental Protection Agency (EPA) requirements for long-term isolation of radioactive and hazardous wastes. The Systems Prioritization Method (SPM), was designed by Sandia National Laboratories to: (1) identify programmatic options (activities), their costs and durations; (2) analyze combinations of activities in terms of their predicted contribution to long-term performance of the WIPP disposal system; and (3) analyze cost, duration, and performance tradeoffs. SPM results were the basis for activities recommended to DOE/CAO in May 1995. SPM identified eight activities (less than 15% of the 58 proposed for consideration) predicted to be essential in addressing key regulatory issues. The SPM method proved useful for risk or performance-based prioritization in which options are interdependent and system behavior is nonlinear. 10 refs., 2 figs., 1 tab.

A series of eight fire tests with simulated radioactive material shipping containers aboard the test ship Mayo Lykes, a break-bulk freighter, is described. The tests simulate three basic types of fires: engine room fires, cargo fires and open pool fires. Detailed results from the tests include temperatures, heat fluxes and air flows measured during the fires. The first examination of the results indicates that shipboard fires are not significantly different from fires encountered in land transport. 13 refs., 15 figs., 11 tabs.

An extension to classical covariance control methods, introduced by Skelton and co-workers, is proposed specifically for application to the control of civil engineering structures subjected to random dynamic excitations. The covariance structure of the system is developed directly from specification of its reliability via the assumption of independent (Poisson) outcrossings of its stationary response process from a polyhedral safe region. This leads to a set of state covariance controllers, each of which guarantees that the closed-loop system will possess the specified level of reliability. An example civil engineering structure is considered.

The effect of dose rate on radiation-induced gain degradation is compared for verticle npn and lateral pnp bipolar transistors. High dose rate irradiations at elevated temperatures are more effective at simulating low dose rate degradation in the lateral pnp transistors.

Effects of irradiation and annealing temperature on radiation-induced charge densities are explored for MOS transistors. Both interface- and border-trap density increase with increasing radiation temperature, while the net oxide-trap charge density decreases.

The ionizing radiation response of several semiconductor process technologies has been shown to be enhanced by plastic packaging and/or pre-conditioning (burn-in). Potential mechanisms for this effect are discussed and data on bipolar linear circuits are presented.

For FY97, the LDRD National Grand Challenges Investment Area initiated three new projects with the goal of developing an integrated approach to chemical microsystems. Collectively, these projects promise to deliver a distributed system of fully integrated, autonomous chemical sensor microsystems (e.g., a handheld or smaller device to detect explosives in airports or chemical warfare agents in the battle field) and the microscience foundation to extend this concept to a wide range of applications. Reaching this goal will require research, development and integration over a wide range of technologies; some that have already been demonstrated and others that do not yet existence. This report documents the completion of the first project task: an assessment of the science and technology base needed to achieve the overall goals. The report is comprised of ten separate assessments, each focused on specific technology areas that were identified as having critical impact on the development of integrated chemical microsystems. Technical staff throughout SNL contributed to these assessments. Each section addresses the state of current technological developments in that technical area and forecasts the future science and technology needed to drive toward higher levels of miniaturization and integration in these systems. This report provides an important guide to the technical investments needed to achieve the National Grand Challenge goals in addition to clearly identifying valuable partnering opportunities with industry, university and other national laboratories. The ten areas of evaluation are: sampling, preconcentration, and separation; pumps, valves, plumbing; optical detection; acoustic detection; other detection approaches; power sources; data analysis; packaging and assembly; analog/digital microelectronics; and mobile platforms.

No abstract available.

Windows NT desktop and server systems are becoming increasingly important to Sandia. These systems are capable of network performance considerably in excess of the 10 Mbps Ethernet data rate. As alternatives to conventional Ethernet, 155 Mbps Asynchronous Transfer Mode, ATM, and 100 Mbps Ethernet network interface cards were tested and compared to conventional 10 Mbps Ethernet cards in a typical Windows NT system. The results of the tests were analyzed and compared to show the advantages of the alternative technologies. Both 155 Mbps ATM and 100 Mbps Ethernet offer significant performance improvements over conventional 10 Mbps shared media Ethernet.

Measurements of the deuterium particle flux and energy to the divertor of the DIII-D tokamak during a series of plasmas that terminated in disruptions have been made using a silicon collector probe installed on the DiMES (divertor materials exposure system) mechanism. During the steady state portion of each discharge, the probe was located in the private flux region, but immediately before disrupting the plasma, by injecting either Ar or D2 gas, the strike point of the outer divertor leg was positioned over the probe. Comparison of the amount of retained D in the probe for the two types of disruptions indicates that much of the trapped D could have resulted from exposure in the private flux zone prior to the disruption. Measurements of the depth distribution of the trapped D in the Si imply that the incident ion energy was approximately 100 eV at normal incidence and decreased slightly at oblique angles. The measurements give an upper bound to the energy of deuterons striking the divertor floor in the vicinity of the strikepoint during disruptions.

Thin metal films (∼ 100 nm thick) of Be, W, V and Mo, were deposited on a Si depth-marked graphite sample and exposed to the steady-state outer strike point on DIII-D in order to measure their respective erosion rates. Gross erosion rates and redeposition lengths are found to decrease with the atomic number of the metallic species, as expected. The maximum net erosion rate for carbon, which occurs near the separatrix, increased from 4 to 16 nm/s when the incident heat flux was increased from 0.7 to 2 MW/m2. Comparisons of the measured carbon erosion with REDEP code calculations show good agreement for both the absolute net erosion rate and its spatial variation. Visible spectroscopic measurements of singly ionized Be (BeII 4674 Å) have determined that the erosion process reaches steady-state during the exposure.

The ability to image complex geologies such as salt domes in the Gulf of Mexico and thrusts in mountainous regions is a key to reducing the risk and cost associated with oil and gas exploration. Imaging these structures, however, is computationally expensive. Datasets can be terabytes in size, and the processing time required for the multiple iterations needed to produce a velocity model can take months, even with the massively parallel computers available today. Some algorithms, such as 3D, finite-difference, prestack, depth migration remain beyond the capacity of production seismic processing. Massively parallel processors (MPPs) and algorithms research are the tools that will enable this project to provide new seismic processing capabilities to the oil and gas industry. The goals of this work are to (1) develop finite-difference algorithms for 3D, prestack, depth migration; (2) develop efficient computational approaches for seismic imaging and for processing terabyte datasets on massively parallel computers; and (3) develop a modular, portable, seismic imaging code.

This document specifies signaling procedures required to support security services in the Phase I ATM Security Specification. These signaling procedures are in addition to those described in UNI 4.0 Signaling. When establishing point-to-point and point-to-multipoint calls, the call control procedures described in the ATM Forum UNI 4.0 Signaling apply. This document describes the additional information elements and procedures necessary to support security services. This description is in an incremental form with differences from the point-to-point and point-to-multipoint calls with respect to messages, information elements, and signaling procedures.

The optical performance of refractive index structures induced in photosensitive (PS) glasses ultimately depends on the index modulation depth attainable. In germanosilicate materials, the photosensitive response is linked to the presence of oxygen-deficient germanium point defect centers. Prior efforts to increase PS in these materials, e.g., hydrogen loading, rely on a chemical reduction of the glass structure to enhance the population of oxygen deficient centers and thus increase the saturated refractive index change. We have previously reported the development of highly photosensitive, as-deposited germanosilicate glass films through reactive atmosphere (O{sub 2}/Ar) sputtering from a Ge/Si alloy target. The present work details our investigation of the effect of substrate temperature during deposition on the material structure and propensity for photosensitivity. Using optical absorption/bleaching, Raman, electron paramagnetic resonance (EPR) and selective charge injection techniques we show that the predominate defect states responsible for the PS response can be varied through substrate temperature control. We find that two regimes of photosensitive behavior can be accessed which exhibit dramatically different uv-bleaching characteristics. Thus, the corresponding dispersion of the refractive index change as well as its magnitude can be controlled using our synthesis technique. Tentative defect models for the photosensitive process in materials deposited at both ambient temperature and at elevated substrate temperatures will be presented.

If photonic data and power transfer links are constructed in a modular fashion, they can be easily adapted into various forms to meet a wide range of needs for aerospace and military applications. The performance specifications associated with these needs can vary widely according to application. Alignment tolerance needs also tend to vary greatly, as can requirements on power consumption. An example of a modular photonic data and/or power transfer link that can be applied to military and aerospace needs is presented. In this approach, a link is designed for low (<10 kb/s) data rates, ultra-low electrical power consumption, large alignment tolerance, and power transfer to provide complete electrical shielding in a remote module that might be found in a military or aerospace application.

The effects of heterogeneities on the performance of capillary barriers is investigated by simulating three systems comprised of a fine soil layer overlying a coarse gravel layer with homogeneous, layered heterogeneous, and random heterogeneous property fields. The amount of lateral diversion above the coarse layer under steady-state infiltration conditions is compared between the simulations. Results indicate that the performance of capillary barriers may be significantly influenced by the spatial variability of the properties. The layered heterogeneous system performed best as a result of horizontal features within the fine layer that acted as additional local capillary barriers that delayed breakthrough into the coarse layer. The random heterogeneous system performed worst because of channeled flow that produced localized regions of water breakthrough into the coarse layer. These results indicate that engineered capillary barriers may be improved through emplacement and packing methods that induce a layered system similar to the layered heterogeneous field simulated in this study.

While a number of technologies or methods of subsurface imaging and monitoring exist, most require some adaptation to meet the site-specific objectives of a particular in-situ waste containment/stabilization verification and monitoring program. The selection of methods and their site-specific adaptation must be based on sound, scientific principles. Given this, specific information about the site and the objectives of the containment or remediation are required to design and implement an appropriate and effective verification and monitoring program. Site and technology information that must be considered and how it affects the selection and adaptation of monitoring technologies is presented. In general, this information includes the objectives of the containment or remediation, the verification and monitoring systems, and the physical properties of the site and the waste containment/stabilization system. The objectives of the containment or remediation and the verification and monitoring system must be defined to provide a goal for the technology developer`s design. The physical properties of the site and the waste containment/stabilization system are required to ensure the proper technology is selected. A conceptual framework and examples are given to demonstrate the impacts of these aspects on technology selection.

Mean arc voltage is a process parameter commonly used in vacuum arc remelting (VAR) control schemes. The response of this parameter to changes in melting current (I) and electrode gap (g{sub e}) at constant pressure may be accurately described by an equation of the form V = V{sub 0} + c{sub 1}g{sub e}I + c{sub 2}g{sub e}{sup 2} + c{sub 3}I{sup 2}, where c{sub 1}, c{sub 2} and c{sub 3} are constants, and where the non-linear terms generally constitute a relatively small correction. If the non-linear terms are ignored, the equation has the form of Ohm`s law with a constant offset (V{sub 0}), c{sub 1}g{sub e} playing the role of resistance. This implies that the arc column may be treated approximately as a simple resistor during constant current VAR, the resistance changing linearly with g{sub e}. The VAR furnace arc is known to originate from multiple cathode spot clusters situated randomly on the electrode tip surface. Each cluster marks a point of exist for conduction electrons leaving the cathode surface and entering the electrode gap. Because the spot clusters re highly localized on the cathode surface, each gives rise to an arc column that may be considered to operate independently of other local arc columns. This approximation is used to develop a model that accounts for the observed arc voltage dependence on electrode gap at constant current. Local arc column resistivity is estimated from elementary plasma physics and used to test the model for consistency by using it to predict local column heavy particle density. Furthermore, it is shown that the local arc column resistance increases as particle density increases. This is used to account for the common observation that the arc stiffens with increasing current, i.e. the arc voltage becomes more sensitive to changes in electrode gap as the melting current is increased. This explains why arc voltage is an accurate electrode gap indicator for high current VAR processes but not low current VAR processes.

The collapse of the Soviet Union has left many of its scientific institutes and technical universities without their traditional backbone of financial support. In an effort to stem the export of science to nations advocating nuclear proliferation, and to acquire potentially useful technology, several US government-sponsored programs have arise to mine the best of former USSR scientific advances. In the field of metallurgy, the earliest institutes to be investigated by Sandia National Laboratories are located in Ukraine. In particular, scientists at the State Metallurgical Academy have developed unique porous metals, resembling what could be described as gas-solid ``eutectic``. While porous metals are available in the US and other western countries, none have the remarkable structure and properties of these materials. Sandia began a collaborative program with the Ukrainian scientists to bring this technology to the US, verify the claims regarding these materials, and begin production of the so-called Gasars. This paper will describe the casting process technology and metallurgy associated with the production of Gasars, and will review the progress of the collaborative project.

The authors have performed electron spin resonance and electrical measurements on SiO{sub 2}/Si structures subjected to anneals in 5% H{sub 2}/N{sub 2} or 5% D{sub 2}/N{sub 2} gases and subsequently injected with electrons using corona ions and ultra-violet radiation. Threshold voltage and transconductance measurements have also been made on 0.25 {micro}m metal-oxide-semiconductor transistors subjected to 400 C anneals in the same gases and subsequently aged by hot electron injection. The electrical data on SiO{sub 2}/Si structures indicates that the density of interface states increases as a result of electron injection but that there are only minor differences between H and D passivated interfaces. The data on P{sub b}, trivalent Si dangling bond, centers at the same interfaces observed by electron spin resonance is insufficiently accurate to enable them to observe any significant differences. The hot electron injection experiments on transistors, consistent with other authors, indicate that, for the limited number of measurements they have made, the transistor aging resulting from the generation of interface states is significantly reduced for devices annealed in the D containing gas as compared to those annealed in the H containing gas. The origins of some potential differences in annealing behavior between the SiO{sub 2}/Si structures and the 0.25 {micro}m transistors are suggested.

The electronics radiation hardness-testing community uses the ASTM E722-93 Standard Practice to define the energy dependence of the nonionizing neutron damage to silicon semiconductors. This neutron displacement damage response function is defined to be equal to the silicon displacement kerma as calculated from the ORNL Si cross-section evaluation. Experimental work has shown that observed damage ratios at various test facilities agree with the defined response function to within 5%. Here, a covariance matrix for the silicon 1-MeV neutron displacement damage function is developed. This uncertainty data will support the electronic radiation hardness-testing community and will permit silicon displacement damage sensors to be used in least squares spectrum adjustment codes.

Typical industrial ESR melting practice includes operation at a constant current. This constant current operation is achieved through the use of a power supply whose output provides this constant current characteristic. Analysis of this melting mode indicates that the ESR process under conditions of constant current is inherently unstable. Analysis also indicates that ESR melting under the condition of a constant applied voltage yields a process which is inherently stable. This paper reviews the process stability arguments for both constant current and constant voltage operation. Explanations are given as to why there is a difference between the two modes of operation. Finally, constant voltage process considerations such as melt rate control, response to electrode anomalies and impact on solidification will be discussed.

Approximate probabilities of inclusion survival through an electron beam melting hearth are computed from nitride dissolution rates, flotation velocities, and residence times. Dissolution rates were determined by measuring shrinkage rates of pure TiN and nitrided sponge in small pools of molten titanium in an electron beam melting hearth. Flotation velocities were calculated using correlations for fluid flow around spheres, and show that particles sink or float unless their densities are extremely close to that of molten titanium. Flow field characteristics which lead to effective inclusion removal are discussed in terms of heat flux pattern required to produce them, based on the electron beam`s unique ability to impart a nearly arbitrary heat flux pattern to the melt surface.

New dosimetry cross-section evaluations have been made available to the reactor community. Most dosimetry-quality evaluations include a section (File 33) that defines the uncertainty and covariance matrix for the dosimetry reaction cross section. This paper compares the latest computed cross-section activities for benchmark neutron fields with experimental data. Uncertainty data is usually reported with experimental measurements. This work also presents uncertainty data for the calculated activities. The calculated uncertainty values include a full uncertainty propagation using the cross-section evaluation, energy-dependent covariance data as well as the uncertainty attributed to the knowledge of the neutron spectrum.

Deterioration of monuments, buildings, and works of art constructed of carbonate-based stone potentially can be arrested by applying a combination of chemical passivants and consolidants that prevent hydrolytic attack and mechanical weakening. The authors used molecular modeling and laboratory synthesis to develop an improved passivating agent for the calcite mineral surface based on binding strength and molecular packing density. The effectiveness of the passivating agent with and without a linked outer layer of consolidant against chemical weathering was determined through leaching tests conducted with a pH-stat apparatus at pH 5 and 25 C. For the range of molecules considered, modeling results indicate that the strongest-binding passivant is the trimethoxy dianionic form of silylalkylaminocarboxylate (SAAC). The same form of silylalkylphosphonate (SAP) is the second strongest binder and the trisilanol neutral form of aminoethylaminopropylsilane (AEAPS) is ranked third. Short-term leaching tests on calcite powders coated with the trisilanol derivative of SAAC, the triethoxy neutral form of SAP, and the trimethoxy neutral form of AEAPS show that the passivant alone does not significantly slow the dissolution rate. However, all passivants when linked to the sol consolidant result in decreased rates. Combined AEAPS plus consolidant results in a coating that performs better than the commercial product Conservare{reg_sign} OH and at least as well as Conservare{reg_sign} H. The modeling results indicate that there may be a threshold binding energy for the passivant above which the dissolution rate of calcite is actually enhanced. More strongly-binding passivants may aid in the dissolution mechanism or dissociate in aqueous solution exposing the calcite surface to water.

An optoelectronic integrated circuit for generating mm-wave frequencies is demonstrated and design issues detailed. A monolithically integrated ring laser, optical amplifier, and photodiode generate electrical signals up to 85.2 GHz.

The use of commercial off-the-shelf (COTS) microelectronics for nuclear weapon applications will soon be reality rather than hearsay. The use of COTS for new technologies for uniquely military applications is being driven by the so-called Perry Initiative that requires the U.S. Department of Defense (DoD) to accept and utilize commercial standards for procurement of military systems. Based on this philosophy, coupled with several practical considerations, new weapons systems as well as future upgrades will contain plastic encapsulated microelectronics. However, a conservative Department of Energy (DOE) approach requires lifetime predictive models. Thus, the focus of the current project is on accelerated testing to advance current aging models as well as on the development of the methodology to be used during WR qualification of plastic encapsulated microelectronics. An additional focal point involves achieving awareness of commercial capabilities, materials, and processes. One of the major outcomes of the project has been the definition of proper techniques for handling and evaluation of modern surface mount parts which might be used in future systems. This program is also raising the familiarity level of plastic within the weapons complex, allowing subsystem design rules accommodating COTS to evolve. A two year program plan is presented along with test results and commercial interactions during this first year.

Studies by academia, industry, and government indicate that applying a sound systems engineering process to development programs is an important tool for preventing cost and schedule overruns and performance deficiencies. There is an enormous body of systems engineering knowledge. Where does one start? How can the principles of systems engineering be applied in the Sandia environment? This road map is intended to be an aid to answering these questions.

The traditional geometry for surface mount devices is the peripheral array where the leads are on the edges of the device. As the technology drives towards high input/output (I/O) count (increasing number of leads) and smaller packages with finer pitch (less distance between peripheral leads), limitations on peripheral surface mount devices arise. The leads on these fine pitch devices are fragile and can be easily bent. It becomes increasingly difficult to deliver solder past to leads spaced as little as 0.012 inch apart. Too much solder mass can result in bridging between leads while too little solder can contribute to the loss of mechanical and electrical continuity. A solution is to shift the leads from the periphery of the device to the area under the device. This scheme is called areal array packaging and is exemplified by the ball grid array (BGA) package. A system has been designed and constructed to deposit an entire array of several hundred uniform solder droplets onto a printed circuit board in a fraction of a second. The solder droplets wet to the interconnect lands on a pc board and forms a basis for later application of a BGA device. The system consists of a piezoelectric solder pulse unit, heater controls, an inert gas chamber and an analog power supply/pulse unit.

On-Machine Acceptance (OMA) is an agile manufacturing concept being developed for machine tools at SNL. The concept behind OMA is the integration of product design, fabrication, and qualification processes by using the machining center as a fabrication and inspection tool. This report documents the final results of a Laboratory Directed Research and Development effort to qualify OMA.

Molecular Beam Epitaxy (MBE) of semiconductor heterostructures for advanced electronic and opto-electronic devices requires precise control of the surface composition and strain. The development of advanced in situ diagnostics for real-time monitoring and process control of strain and composition would enhance the yield, reliability and process flexibility of material grown by MBE and benefit leading-edge programs in microelectronics and photonics. The authors have developed a real-time laser-based technique to measure the evolution of stress in epitaxial films during growth by monitoring the change in the wafer curvature. Research has focused on the evolution of stress during the epitaxial growth of Si{sub x}Ge{sub 1{minus}x} alloys on Si(001) substrates. Initial studies have observed the onset and kinetics of strain relaxation during the growth of heteroepitaxial layers. The technique has also been used to measure the segregation of Ge to the surface during alloy growth with monolayer sensitivity, an order of magnitude better resolution than post-growth characterization. In addition, creation of a 2-dimensional array of parallel beams allows rapid surface profiling of the film stress that can be used to monitor process uniformity.

This work is comprised of two major sections. In the first section the authors develop multivariate image classification techniques to distinguish and identify surface electronic species directly from multiple-bias scanning tunneling microscope (STM) images. Multiple measurements at each site are used to distinguish and categorize inequivalent electronic or atomic species on the surface via a computerized classification algorithm. Then, comparison with theory or other suitably chosen experimental data enables the identification of each class. They demonstrate the technique by analyzing dual-polarity constant-current topographs of the Ge(111) surface. Just two measurements, negative- and positive-bias topography height, permit pixels to be separated into seven different classes. Labeling four of the classes as adatoms, first-layer atoms, and two inequivalent rest-atom sites, they find excellent agreement with the c(2 x 8) structure. The remaining classes are associated with structural defects and contaminants. This work represents a first step toward developing a general electronic/chemical classification and identification tool for multivariate scanning probe microscopy imagery. In the second section they report measurements of the diffusion of Si dimers on the Si(001) surface at temperatures between room temperature and 128 C using a novel atom-tracking technique that can resolve every diffusion event. The atom tracker employs lateral-positioning feedback to lock the STM probe tip into position above selected atoms with sub-Angstrom precision. Once locked the STM tracks the position of the atoms as they migrate over the crystal surface. By tracking individual atoms directly, the ability of the instrument to measure dynamic events is increased by a factor of {approximately} 1,000 over conventional STM imaging techniques.

Graph partitioning is an important abstraction used in solving many scientific computing problems. Unfortunately, the standard partitioning model does not incorporate considerations that are important in many settings. We address this by describing a generalized partitioning model which incorporates the notion of partition skew and is applicable to a variety of problems. We then develop enhancements to several important partitioning algorithms necessary to solve the generalized partitioning problem. Finally we demonstrate the benefit of employing several of these generalized methods to static decomposition of parallel computing problems.

A popular method for updating finite element models with modal test data utilizes optimization of the model based on design sensitivities. The attractive feature of this technique is that it allows some estimate and update of the physical parameters affecting the hardware dynamics. Two difficulties are knowing which physical parameters are important and which of those important parameters are in error. If this is known, the updating process is simply running through the mechanics of the optimization. Most models of real systems have a myriad of parameters. This paper discusses an implementation of a tool which uses the model and test data together to discover which parameters are most important and most in error. Some insight about the validity of the model form may also be obtained. Experience gained from applications to complex models will be shared.

The disposition of the large back-log of plutonium residues at the Rocky Flats Environmental Technology Site (Rocky Flats) will require interim storage and subsequent shipment to a waste repository. Current plans call for disposal at the Waste Isolation Pilot Plant (WIPP) and the transportation to WIPP in the TRUPACT-II. The transportation phase will require the residues to be packaged in a container that is more robust than a standard 55-gallon waste drum. Rocky Flats has designed the Pipe Overpack Container to meet this need. It is desirable to use this same waste packaging for interim on-site storage in non-hardened buildings. To meet the safety concerns for this storage the Pipe Overpack Container has been subjected to a series of tests at Sandia National Laboratories in Albuquerque, New Mexico. In addition to the tests required to qualify the Pipe Overpack Container as a waste container for shipment in the TRUPACT-II several tests were performed solely for the purpose of qualifying the container for interim storage. This report will describe these tests and the packages response to the tests. 12 figs., 3 tabs.

There is a void of public specifications for pulse discharge capacitor applications. Sandia National Laboratories has developed, over the past 25 years, specifications and test procedures for evaluating capacitor designs for this specialized use. There are three primary destructive tests that are used to assess the reliability potential of a given design at a required rated voltage. These are ultimate short time breakdown strength, life at voltage, and pulse discharge life. The strategy of the method is to accelerate the test conditions so that failures are observable and then extrapolate to the desired use conditions where the failure rates are low. This paper will present the statistical methodologies employed to analyze experimental data and to provide a point estimate of reliability with a lower confidence bound as a function of rated voltage. In addition, methods for establishing lot-acceptance-criteria specifications will be discussed. The techniques will be illustrated with actual data on a commercially available, low-inductance, pulse-discharge capacitor. The capacitor is an impregnated dual dielectric (mica-paper/polymer film), extended-foil type.

The scanning force microscopies (notably the Atomic Force Microscope--AFM), because of their applicability to nearly all materials, are presently the most widely used of the scanning-probe techniques. However, the AFM uses a deflection sensor to measure sample/probe forces which suffers from an inherent mechanical instability that occurs when the rate of change of the force with respect to the interfacial separation becomes equal to the spring constant of the deflecting member. This instability dramatically limits the breadth of applicability of AFM-type techniques to materials problems. In the course of implementing a DOE sponsored basic research program in interfacial adhesion, a self-balancing force sensor concept has been developed and incorporated into an Interfacial Force Microscopy (IFM) system by Sandia scientists. This sensor eliminates the instability problem and greatly enhances the applicability of the scanning force-probe technique to a broader range of materials and materials parameters. The impact of this Sandia development was recognized in 1993 by a Department of Energy award for potential impact on DOE programs and by an R and D 100 award for one of the most important new products of 1994. However, in its present stage of development, the IFM is strictly a research-level tool and a CRADA was initiated in order to bring this sensor technology into wide-spread availability by making it accessible in the form of a commercial instrument. The present report described the goals, approach and results of this CRADA effort.

In this presentation, the authors will investigate the use of hybrid meshes for modeling RCS and antenna problems in three dimensions. They will consider two classes of hybrid basis functions. These include combinations of quadrilateral and triangular meshes for arbitrary 3D geometries, and combinations of axisymmetric body-of-revolution (BOR) basis functions and triangular facets. In particular, they will focus on the problem of enforcing current continuity between two surfaces which are represented by different types of surface discretizations and unknown basis function representations. They will illustrate the use of an operator-based code architecture for the implementation of these formulations, and how it facilitates the incorporation of the various types of boundary conditions in the code. Both serial and parallel code implementation issues for the formulations will be discussed. Results will be presented for both scattering and antenna problems. The emphasis will be on accuracy, and robustness of the techniques. Comparisons of accuracy between triangular meshed and quadrilateral meshed geometries will be shown. The use of hybrid meshes for modeling BORs with attached appendages will also be presented.

The Surtsey Test Facility is used to perform scaled experiments simulating High Pressure Melt Ejection accidents in a nuclear power plant (NPP). The experiments investigate the effects of direct containment heating (DCH) on the containment load. The results from Zion and Surry experiments can be extrapolated to other Westinghouse plants, but predicted containment loads cannot be generalized to all Combustion Engineering (CE) plants. Five CE plants have melt dispersal flow paths which circumvent the main mitigation of containment compartmentalization in most Westinghouse PWRs. Calvert Cliff-like plant geometries and the impact of codispersed water were addressed as part of the DCH issue resolution. Integral effects tests were performed with a scale model of the Calvert Cliffs NPP inside the Surtsey test vessel. The experiments investigated the effects of codispersal of water, steam, and molten core stimulant materials on DCH loads under prototypic accident conditions and plant configurations. The results indicated that large amounts of coejected water reduced the DCH load by a small amount. Large amounts of debris were dispersed from the cavity to the upper dome (via the annular gap). 22 refs., 84 figs., 30 tabs.

This report presents automatic motion planning algorithms for robotic manipulators performing a variety of tasks. Given a task and a robot manipulator equipped with a tool in its hand, the motion planners compute robot motions to complete the task while respecting manipulator kinematic constraints and avoiding collisions with objects in the robot`s work space. To handle the high complexity of the motion planning problem, a sophisticated search strategy called SANDROS is developed and used to solve many variations of the motion planning problem. To facilitate systematic development of motion planning algorithms, robotic tasks are classified into three categories according to the dimension of the manifold the robot tool has to travel: visit-point (0 dimensional), trace-curve (1 dimensional) and cover-surface (2 dimensional) tasks. The motion planner for a particular dimension is used as a sub-module by the motion planner for the next-higher dimension. This hierarchy of motion planners has led to a set of compact and systematic algorithms that can plan robot motions for many types of robotic operations. In addition, an algorithm is developed that determines the optimal robot-base configuration for minimum cycle time. The SANDROS search paradigm is complete in that it finds a solution path if one exists, up to a user specified resolution. Although its worst-case time complexity is exponential in the degrees of freedom of the manipulator, its average performance is commensurate with the complexity of the solution path. Since solution paths for most of motion planning problems consist of a few monotone segments, the motion planners based on SANDROS search strategy show approximately two-orders of magnitude improvements over existing complete algorithms.

Under the sponsorship of the Department of Energy, Office of Utility Technologies, the Energy Storage System Analysis and Development Department at Sandia National Laboratories (SNL) conducted a cost analysis of energy storage systems for electric utility applications. The scope of the study included the analysis of costs for existing and planned battery, SMES, and flywheel energy storage systems. The analysis also identified the potential for cost reduction of key components.

A robot`s configuration space (c-space) is the space of its kinematic degrees of freedom, e.g., the joint-space of an arm. Sets in c-space can be defined that characterize a variety of spatial relationships, such as contact between the robot and its environment. C-space techniques have been fundamental to research progress in areas such as motion planning and physically-based reasoning. However, practical progress has been slowed by the difficulty of implementing the c-space abstraction inside each application. For this reason, we proposed a Configuration Space Toolkit of high-performance algorithms and data structures meeting these needs. Our intent was to develop this robotics software to provide enabling technology to emerging applications that apply the c-space abstraction, such as advanced motion planning, teleoperation supervision, mechanism functional analysis, and design tools. This final report presents the research results and technical achievements of this LDRD project. Key results and achievements included (1) a hybrid Common LISP/C prototype that implements the basic C-Space abstraction, (2) a new, generic, algorithm for constructing hierarchical geometric representations, and (3) a C++ implementation of an algorithm for fast distance computation, interference detection, and c-space point-classification. Since the project conclusion, motion planning researchers in Sandia`s Intelligent Systems and Robotics Center have been using the CSTk libcstk.so C++ library. The code continues to be used, supported, and improved by projects in the ISRC.

Under the sponsorship of the Department of Energy, Office of Utility Technologies, the Energy Storage System Analysis and Development Department at Sandia National Laboratories (SNL) conducted a cost analysis of energy storage systems for electric utility applications. The scope of the study included the analysis of costs for existing and planned battery, SMES, and flywheel energy storage systems. The analysis also identified the potential for cost reduction of key components.

Sandia`s Superconductivity Technology Program is a thallium-based high-temperature superconductor (HTS) research and development program consisting of efforts in powder synthesis and process development, open-system thick film conductor development, wire and tape fabrication, and HTS motor design. The objective of this work is to develop high-temperature superconducting conductors (wire and tape) capable of meeting requirements for high-power electrical devices of interest to industry. The research efforts currently underway are: (1) Process development and characterization of thallium-based high-temperature superconducting closed system wire and tape, (2) Investigation of the synthesis and processing of thallium-based thick films using two-zone processing, and (3) Cryogenic design of a 30K superconducting motor. This report outlines the research that has been performed during FY96 in each of these areas.

A pulsed rf plasma technique is capable of generating ceramic particles of 10 manometer dimension. Experiments using silane/ammonia and trimethylchlorosilane/hydrogen gas mixtures show that both silicon nitride and silicon carbide powders can be synthesized with control of the average particle diameter from 7 to 200 nm. Large size dispersion and much agglomeration appear characteristic of the method, in contrast to results reported by another research group. The as produced powders have a high hydrogen content and are air and moisture sensitive. Post-plasma treatment in a controlled atmosphere at elevated temperature (800{degrees}C) eliminates the hydrogen and stabilizes the powder with respect to oxidation or hydrolysis.

The Waste Isolation Pilot Plant (WIPP), a facility located in a bedded salt formation in Carlsbad, New Mexico, is being used by the U.S. Department of Energy to demonstrate the technology for safe handling and disposal of transuranic wastes produced by defense activities in the United States. In support of that demonstration, mechanical tests on salt were conducted in the laboratory to characterize material behavior at the stresses and temperatures expected for a nuclear waste repository. Many of those laboratory test programs have been carried out in the RE/SPEC Inc. rock mechanics laboratory in Rapid City, South Dakota; the first program being authorized in 1975 followed by additional testing programs that continue to the present. All of the WIPP laboratory data generated on salt at RE/SPEC Inc. over the last 20 years is presented in this data report. A variety of test procedures were used in performance of the work including quasi-static triaxial compression tests, constant stress (creep) tests, damage recovery tests, and multiaxial creep tests. The detailed data is presented in individual plots for each specimen tested. Typically, the controlled test conditions applied to each specimen are presented in a plot followed by additional plots of the measured specimen response. Extensive tables are included to summarize the tests that were performed. Both the tables and the plots contain cross-references to the technical reports where the data were originally reported. Also included are general descriptions of laboratory facilities, equipment, and procedures used to perform the work.

A nonnalized X-ray induced gain coefficient, 1.48 x 10{sup -3} cm{sup -1}/krad, has been determined for Cr,Nd:GSGG. Hermes III, a 20 ns, 2 MeV X-ray source, is used to irradiate the sample. Doping levels of 1 x 10{sup 20} and 2 x 10{sup 20} /cm{sup 3} respectively, for Cr and Nd are used. A proposed heuristic model in which excited Gd transfers its excitation to Cr which then transfers its excitation to Nd is described.

A study is underway to identify a rapid, easy method for determining cleanliness levels during the manufacture of neutron tubes. Due to high reliability concerns associated with neutron tubes, cleanliness levels of metal and ceramic piece parts are critical. Sandia has traditionally used quantitative surface analytical methods, such as Auger Electron Spectroscopy and X-ray Photoelectron Spectroscopy for determining cleanliness levels. A critical disadvantage of these techniques is the time required to perform them. More rapid, reliable methods are needed for in-line testing of neutron tube assemblies. Several methods including contact angle, MESERAN, Fourier Transform Infrared Spectroscopy, and Optically Stimulated Electron Emission measurements are being evaluated as potential candidates. Cleanliness levels for each of these methods have been compared to Auger Electron Spectroscopy results, after processing samples through similar test conditions. An attempt was made to correlate the results from the alternative methods to those of Auger Electron Spectroscopy. Test results are presented.

Modular fixturing kits are sets of components used for flexible, rapid construction of fixtures. A modular vise is a parallel-jaw vise, each jaw of which is a modular fixture plate with a regular grid of precisely positioned holes. To fixture a part, one places pins in some of the holes so that when the vise is closed, the part is reliably located and completely constrained. The modular vise concept can be adapted easily to the design of modular parallel-jaw grippers for robots. By attaching a grid-plate to each jaw of a parallel-jaw gripper, one gains the ability to easily construct high-quality grasps for a wide variety of parts from a standard set of hardware. Wallack and Canny developed an algorithm for planning planar grasp configurations for the modular vise. In this paper, the authors expand this work to produce a 3-d fixture/gripper design tool. They describe several analyses they have added to the planar algorithm, including a 3-d grasp quality metric based on force information, 3-d geometric loading analysis, and inter-gripper interference analysis. Finally, the authors describe two applications of their code. One of these is an internal application at Sandia, while the other shows a potential use of the code for designing part of an agile assembly line.

With a goal of producing faster, safer, and cheaper technologies for nuclear waste cleanup, Sandia is actively developing and extending intelligent systems technologies. Graphical Programming is a key technology for robotic waste cleanup that Sandia is developing for this goal. This paper describes Sancho, Sandia most advanced Graphical Programming supervisory software. Sancho, now operational on several robot systems, incorporates all of Sandia`s recent advances in supervisory control. Sancho, developed to rapidly apply Graphical Programming on a diverse set of robot systems, uses a general set of tools to implement task and operational behavior. Sancho can be rapidly reconfigured for new tasks and operations without modifying the supervisory code. Other innovations include task-based interfaces, event-based sequencing, and sophisticated GUI design. These innovations have resulted in robot control programs and approaches that are easier and safer to use than teleoperation, off-line programming, or full automation.

In an effort to develop cost-efficient techniques for remediating uranium contaminated groundwater at DOE Uranium Mill Tailing Remedial Action (UMTRA) sites nationwide, Sandia National Laboratories (SNL) deployed a pilot scale research project at an UMTRA site in Durango, CO. Implementation included design, construction, and subsequent monitoring of an in situ passive reactive barrier to remove Uranium from the tailings pile effluent. A reactive subsurface barrier is produced by emplacing a reactant material (in this experiment various forms of metallic iron) in the flow path of the contaminated groundwater. Conceptually the iron media reduces and/or adsorbs uranium in situ to acceptable regulatory levels. In addition, other metals such as Se, Mo, and As have been removed by the reductive/adsorptive process. The primary objective of the experiment was to eliminate the need for surface treatment of tailing pile effluent. Experimental design, and laboratory and field results are discussed with regard to other potential contaminated groundwater treatment applications.

An overview of the operations of Sandia`s Microelectronics Development Lab (MDL) is to develop radiation hardened IC, but techniques used for IC processing have been applied to a variety of related technologies such as micromechanics, smart sensors, and packaging.

A new diode laser using a Tapered-Rib Adiabatic-Following Fiber Coupler to achieve 2D mode expansion and narrow, symmetric far-field emission without epitaxial regrowth or sharply-defined tips on tapered waveguides is presented.

This report presents the results of a development effort to design, test and begin production of a new class of small photovoltaic (PV) charge controllers. Sandia National Laboratories provided technical support, test data and financial support through a Balance-of-System Development contract. One of the objectives of the development was to increase user confidence in small PV systems by improving the reliability and operating life of the system controllers. Another equally important objective was to improve the economics of small PV systems by extending the battery lifetimes. Using new technology and advanced manufacturing techniques, these objectives were accomplished. Because small stand-alone PV systems account for over one third of all PV modules shipped, the positive impact of improving the reliability and economics of PV systems in this market segment will be felt throughout the industry. The results of verification testing of the new product are also included in this report. The initial design goals and specifications were very aggressive, but the extensive testing demonstrates that all the goals were achieved. Production of the product started in May at a rate of 2,000 units per month. Over 40 Morningstar distributors (5 US and 35 overseas) have taken delivery in the first 2 months of shipments. Initial customer reactions to the new controller have been very favorable.

Three characteristic regimes were identified during wet thermal oxidation of AlxGa(1-x)As (x=1 to 0.90) on GaAs: oxidation of Al and Ga in the alloy to form to an amorphous oxide layer, formation and elimination of elemental As and of amorphous As2O3, and crystallization of the oxide film. Residual As can produce up to a 100fold increase in leakage current and a 30% increase in bulk dielectric constant. Very low As levels produce partial Fermi-level pinning at the oxidized AlxGa(1-x)As/GaAs interface. Local Schottky- barrier pinning of the Fermi level at As precipitates at the oxide/GaAs interface may be the source of the apparent high interface state density. The presence of thermodynamically favored interfacial As may impose a fundamental limit on the application of AlGaAs wet oxidation for achieving MIS devices without post-oxidation processing to remove the residual As from the interface.

The primary objective of this project was to further develop close-coupled barrier technology for the containment of subsurface waste or contaminant migration. 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 chemically resistant polymer layer. The technology has matured from a regulatory investigation of issues concerning barriers and barrier materials to a pilot-scale, multiple individual column injections at Sandia National Labs (SNL) to full scale demonstration. The feasibility of this barrier concept was successfully proven in a full scale ``cold site`` demonstration at Hanford, WA. Consequently, a full scale deployment of the technology was conducted at an actual environmental restoration site at Brookhaven National Lab (BNL), Long Island, NY. This paper discusses the installation and performance of a technology deployment implemented at OU-1 an Environmental Restoration Site located at BNL.

The objective of this project is the development of a new class of supramolecular assemblies for applications in biosensors and biodevices. The supramolecular assemblies are based on membranes and Langmuir-Blodgett (LB) films composed of naturally-occurring or synthetic lipids, which contain electrically and/or photochemically active components. The LB films are deposited onto electrically-active materials (metal, semiconductors). The active components film components (lipo-porphyrins) at the surface function as molecular recognition sites for sensing proteins and other biomolecules, and the porphyrins and other components (e.g., fullerenes) incorporated into the films serve as photocatalysts and vectorial electron-transport agents. Computer-aided molecular design (CAMD) methods are used to tailor the structure of these film components to optimize function. Molecular modeling is also used to predict the location, orientation, and motion of these molecular components within the films. The result is a variety of extended, self-assembled molecular structures that serve as devices for sensing proteins and biochemicals or as other bioelectronic devices.

This report summarizes the three-year LDRD program directed at developing catalysts based on metalloporphyrins to reduce carbon dioxide. Ultimately it was envisioned that such catalysts could be made part of a solar-driven photoredox cycle by coupling metalloporphyrins with semiconductor systems. Such a system would provide the energy required for CO{sub 2} reduction to methanol, which is an uphill 6-electron reduction. Molecular modeling and design capabilities were used to engineer metalloporphyrin catalysts for converting CO{sub 2} to CO and higher carbon reduction products like formaldehyde, formate, and methanol. Gas-diffusion electrochemical cells were developed to carry out these reactions. A tin-porphyrin/alumina photocatalyst system was partially developed to couple solar energy to this reduction process.

Plasma discharges involving mixtures of chlorine and boron trichloride are widely used to etch metals in the production of very-large-scale-integrated circuits. Energetic ions play a critical role in this process, influencing the etch rates, etch profiles, and selectivity to different materials. The authors are using a gridded energy analyzer to measure positive ion energy distributions and fluxes at the grounded electrode of high-density inductively-coupled rf discharges. In this paper, they present details of ion energies and fluxes in discharges containing mixtures of chlorine and boron trichloride.

Implementation of optical imagery in a diffuse inhomogeneous medium such as biological tissue requires an understanding of photon migration and multiple scattering processes which act to randomize pathlength and degrade image quality. The nature of transmitted light from soft tissue ranges from the quasi-coherent properties of the minimally scattered component to the random incoherent light of the diffuse component. Recent experimental approaches have emphasized dynamic path-sensitive imaging measurements with either ultrashort laser pulses (ballistic photons) or amplitude modulated laser light launched into tissue (photon density waves) to increase image resolution and transmissive penetration depth. Ballistic imaging seeks to compensate for these {open_quotes}fog-like{close_quotes} effects by temporally isolating the weak early-arriving image-bearing component from the diffusely scattered background using a subpicosecond optical gate superimposed on the transmitted photon time-of-flight distribution. The authors have developed a broadly wavelength tunable (470 nm -2.4 {mu}m), ultrashort amplifying optical gate for transillumination spectral imaging based on optical parametric amplification in a nonlinear crystal. The time-gated image amplification process exhibits low noise and high sensitivity, with gains greater than 104 achievable for low light levels. We report preliminary benchmark experiments in which this system was used to reconstruct, spectrally upcovert, and enhance near-infrared two-dimensional images with feature sizes of 65 {mu}m/mm{sup 2} in background optical attenuations exceeding 10{sup 12}. Phase images of test objects exhibiting both absorptive contrast and diffuse scatter were acquired using a self-referencing Shack-Hartmann wavefront sensor in combination with short-pulse quasi-ballistic gating. The sensor employed a lenslet array based on binary optics technology and was sensitive to optical path distortions approaching {lambda}/100.

A physical model is developed to quantify the contribution of oxide-trapped charge to enhanced low-dose-rate gain degradation in BJTs. Simulations show that space charge limited transport is partially responsible for the low-dose-rate enhancement.

An experimental program was performed that examined the physical and mechanical properties of several candidate, lead (Pb)-free solder alloys. The project was separated into three tasks designated as follows: (1) Alloy Development, (2) Intermetallic Compound (IMC) Growth, and (3) Mechanical Testing. Task 1, Alloy Development, examined the impact that small Pb additions had on the physical and mechanical properties of several Pb-free solders. Task 2, Intermetallic Compound (IMC) Growth investigated the development of the IMC layer between several Pb-free solder alloys and Cu. Quantitative analyses established the kinetics of layer growth in the solid state as a result of elevated temperature aging treatments, and as a function of the composition of the solder. Liquid state IMC layer growth as well as dissolution rates of Cu substrates by molten solders were quantitatively documented. Task 3, Mechanical Properties, performed a series of experiments that provided fracture toughness measurement, thermomechanical fatigue evaluations, and creep deformation data on a number of the Pb-free solders as well as on Pb-free alloys that had been contaminated with controlled quantities of Pb additions. The data obtained from these tests results relative performance information as well as valuable input data for computer models. Several ancillary tests were also performed to support partner company efforts.

Experimental work conducted by D. B. Adolf has shown that a separable K-BKZ constitutive equation works reasonable well in predicting the stress relaxation observed in single step strain experiments for carbon black filled rubber. However, the memory requirements and numerical efficiency of the K-BKZ equation do not make it well suited for use in a production, three-dimensional finite element code. As an alternative, D. J. Segalman, K. Zuo, and D. Parsons have developed a "damage-like" constitutive equation which is computationally attractive. This formalism has been installed in the JAS3D finite element code. The requisite code inputs and numerical details of the constitutive integration are discussed, and solutions to selected problems are presented. Comparisons are made to data collected from both single and double step strain experiments.

DIAMOND FORTUNE was a nuclear explosion detonated inside an 11 m hemispherical cavity in tuff at the Nevada Test Site. Previous cavity explosions such as STERLING and MILL YARD have shown a substantial decrease in the expected ground motion. These types of cavity tests present a serious problem for a Comprehensive Test Ban (CTB). Not only is detection a problem, but presently there is no seismic method to discriminate between a tamped and cavity explosion. DIAMOND FORTUNE allowed us to examine several aspects of a cavity explosion in the context of a CTB. On this test, there were two groups of accelerometers fielded. One group was located in the free-field at sites above and below the cavity within 30 m of the source. The second group consisted of a line of gauges placed in the invert of P-tunnel extending from 44 m to 224 m from the source. The purpose of this arrangement was to measure ground motion in an effort to detect a non-symmetric radiation pattern due to the hemisphere, examine the high frequency propagation of the free-field signals as a possible discriminate, and calculate the decoupling factor. The radiation pattern experiment was conducted in an effort to determine if the asymmetry of a hemispherical cavity could provide a preferred direction of transmission. The analysis indicated a definite radiation pattern with larger amplitudes transmitted through the spherical surface than the plane surface. The possibility of using high frequency signals as a discriminant of tamped versus cavity explosions is implied by the MILL YARD data. MILL YARD was also a nuclear explosion in an 11 m hemispherical cavity. The free-field ground motion signals from this test (<25 m) contained very large high frequency amplitudes ([approx]1000 Hz) in their spectra. DIAMOND FORTUNE also exhibited high frequency signals with comer frequencies twice that of the scaled tamped DISTANT ZENITH event.

The Waste Isolation Pilot Plant (WIPP), located in a salt bed in southern New Mexico, is designed by US Department of Energy to demonstrate the safe and permanent disposal of design-basis transuranic waste. WIPP performance assessment requires consideration of radionuclide release in brines in the event of inadvertent human intrusion. The mobility of radionuclides depends on chemical factors such as brine pmH (-log molality of H{sup +}) and CO{sub 2} fugacity. According to current waste inventory estimates, a large quantity ({approximately} 10{sup 9} moles C) of organic materials will be emplaced in the WIPP. Those organic material will potentially be degraded by halophilic or halotolerant microorganisms in the presence of liquid water in the repository, especially if a large volume of brine is introduced into the repository by human intrusions. Organic material biodegradation will produce a large amount of CO{sub 2}, which will acidify the WIPP brine and thus significantly increase the mobility of actinides. This communication addresses (1) the rate of organic material biodegradation and the quantity of CO{sub 2} to be possibly generated, (2) the effect of microbial CO{sub 2} production on overall WIPP performance, and (3) the mechanism of using MgO to mitigate this effect.

The authors have demonstrated room-temperature CW operation of type-II quantum cascade (QC) light emitting diodes at 4.2 {micro}m using InAs/InGaSb/InAlSb type-II quantum wells. The type-II QC configuration utilizes sequential multiple photon emissions in a staircase of coupled type-II quantum wells. The device was grown by molecular beam epitaxy on a p-type GaSb substrate and was compared of 20 periods of active regions separated by digitally graded quantum well injection regions. The maximum average output power is about 250 {micro}W at 80 K, and 140 {micro}W at 300 K at a repetition rate of 1 kHz with a duty cycle of 50%.

A method is described for generating electron cross sections that are compatible with standard discrete ordinates codes without modification. There are many advantages to using an established discrete ordinates solver, e.g., immediately available adjoint capability. Coupled electron-photon transport capability is needed for many applications, including the modeling of the response of electronics components to space and synthetic radiation environments. The cross sections have been successfully used in the DORT, TWODANT, and TORT discrete ordinates codes. The cross sections are shown to provide accurate and efficient solutions to certain multidimensional electron-photon transport problems. The key to the method is a simultaneous solution of the continuous-slowing-down and elastic-scattering portions of the scattering source by the Goudsmit-Saunderson theory. The resulting multigroup-Legendre cross sections are much smaller than the true scattering cross sections that they represent. Under certain conditions, the cross sections are guaranteed positive and converge with a low-order Legendre expansion.

The electrochemical properties of LiMn2O4 and LiAlxMn2-xO4 (where x = 0.125, 0.25, 0.375) were studied for variations in lithium-ion diffusion. The largest diffusion coefficient was shown for the undoped material, DLi+=2.7×10-11 cm2/s. As the level of dopant was increased a concurrent decrease in diffusion coefficient is shown. This effect was attributed to a decrease in the lattice parameter caused by dopant addition. © 1997 Published by Elsevier Science S.A.

Solid and annular silicon aerogel and agar foams were imploded on the SATURN accelerator to study plasma initiation, acceleration, and stagnation. SATURN delivers 7 MA with a 50 ns rise time to these foam loads. We fielded several spectroscopic diagnostics to measure plasma parameters throughout the z-pinch discharge. A spatially resolved single frame time-gated extreme ultraviolet spectrometer measured the extent of plasma ablation off the surface of the foam. A time integrated crystal spectrometer showed that characteristic K shell radiation of silicon in the aerogel and of sulfur and sodium impurities in the agar were attenuated when the foam loads were coated with a conductive layer of gold. A time-resolved pinhole camera showed that in general the quality of the pinch implosions was poor but improved with increasing efforts to improve current continuity such as prepulse and conductive coatings. © 1997 American Institute of Physics.

A pulsed Na atomic beam source developed for spectroscopic diagnosis of a high-power ion diode is described. The goal is to produce a ∼1012-cm-3-density Na atomic beam that can be injected into the diode acceleration gap to measure electric and magnetic fields from the Stark and Zeeman effects through laser-induced fluorescence or absorption spectroscopy. A ∼10 ns full width at half-maximum (FWHM), 1.06 μm, 0.6 J/cm2 laser incident through a glass slide heats a Na-bearing thin film, creating a plasma that generates a sodium vapor plume. A ∼1 μs FWHM dye laser beam tuned to 5890 Å is used for absorption measurement of the Na I resonant doublet by viewing parallel to the film surface. The dye laser light is coupled through a fiber to a spectrograph with a time-integrated charge-coupled-device camera. A two-dimensional mapping of the Na vapor density is obtained through absorption measurements at different spatial locations. Time-of-flight and Doppler broadening of the absorption with ∼0.1 Å spectral resolution indicate that the Na neutral vapor temperature is about 0.5-2 eV. Laser-induced fluorescence from ∼1×1012 cm-3 Na I 3s-3p lines observed with a streaked spectrograph provides a signal level sufficient for ∼±0.06 Å wavelength shift measurements in a mock-up of an ion diode experiment. © 1997 American Institute of Physics.

We find that significant polarization fatigue (> 90%) can be induced in SrBi2Ta2O9 (SET) thin films using (a) broad-band optical illumination combined with a bias near the switching threshold and (b) electric field cycling under broadband optical illumination. In the latter case, the extent of polarization fatigue increases with decreasing cycling voltage. In either case, the optically fatigued SET capacitors can be fully rejuvenated by applying a saturating dc bias with light or by electric field cycling without light, which suggests a field-assisted recovery mechanism. A similar behavior was observed in Pb(Zr,Ti)O3 (PZT) films with LSCO electrodes. Based on these results, we suggest that polarization fatigue in ferroelectrics is essentially a dynamic competition between domain wall pinning due to electronic charge trapping, and field-assisted unpinning of the domain walls. Thus, domain wall pinning is not necessarily absent in nominally fatigue-free systems. Instead, these systems are ones in which domain wall unpinning occurs at least as rapidly as any pinning. Factors which may affect the pinning and unpinning rates will be discussed.

We describe the application of the techniques of high pressure liquid chromatography (HPLC) to analyze and characterize various types of inorganic nanoclusters. Both metal and semiconductor nanoclusters were grown in inverse micelles and we demonstrate how the nanoclusters can be separated from the surfactants and other byproducts of the reaction by using a variety of HPLC columns. We also discuss passivation of the cluster surface to prevent aggregation. The HPLC columns separate the clusters based upon a combination of size exclusion and chemical affinity mechanisms and the optical properties of the purified clusters are determined on-line using a variety of detectors. These include a photodiode array for collecting absorbance spectra, a fluorescence detector to monitor luminesence, and a conductivity detector to monitor surface charge on the nanoclusters. We illustrate the analysis of nanoclusters using HPLC by showing data from semiconductor Si, MoS2 nanoclusters and Au nanoclusters. An extremely novel luminesence was observed from very small metal nanoclusters. © 1997 Acta Metallurgica Inc.

We have grown AlSb and AlAsxSb1 - x epitaxial layers by metal-organic chemical vapor deposition (MOCVD) using trimethylamine alane or ethyldimethylamine alane, triethylantimony, and arsine. These layers were successfully doped p-or n-type using diethylzinc or tetraethyltin, respectively. We examined the growth of AlAsxSb1 - x using temperatures of 500-600°C, pressures of 65-630 Torr, V/III ratios of 1-17, and growth rates of 0.3-2.7 μm/h in a horizontal quartz reactor. We have also fabricated gain-guided, injection lasers using AlAsxSb1 - x for optical confinement and a strained InAsSb/InAs multi-quantum well active region grown using MOCVD. In pulsed mode, the laser operated up to 210 K with an emission wavelength of 3.8-3.9 μm.

Micro-Electrical Mechanical Systems (MEMS) is an emerging technology with demonstrated potential for a wide range of applications including sensors and actuators for medical, industrial, consumer, military, automotive and instrumentation products. Failure analysis (FA) of MEMS is critically needed for the successful design, fabrication, performance analysis and reliability assurance of this new technology. Many devices have been examined using techniques developed for integrated circuit analysis, including optical inspection, scanning laser microscopy (SLM), scanning electron microscopy (SEM), focused ion beam (FIB) techniques, atomic force microscopy (AFM), infrared (lR) microscopy, light emission (LE) microscopy, acoustic microscopy and acoustic emission analysis. For example, the FIB was used to microsection microengines that developed poor performance characteristics. Subsequent SEM analysis clearly demonstrated the absence of wear on gear, hub, and pin joint bearing surfaces, contrary to expectations. Another example involved the use of infrared microscopy for thermal analysis of operating microengines. Hot spots were located, which did not involve the gear or hub, but indicated contact between comb structures which drive microengines. Voltage contrast imaging proved useful on static and operating MEMS in both the SEM and the FIB and identified electrostatic clamping as a potentially significant contributor to failure mechanisms in microengines. This work describes MEMS devices, FA techniques, failure modes, and examples of FA of MEMS.

We studied whether plasma-etching techniques can use standard screen-printed gridlines as etch masks to form self-aligned, patterned-emitter profiles on multicrystalline-silicon (mc-Si) cells from Solarex. We conducted an investigation of plasma deposition and etching processes on full-size mc-Si cells processed in commercial production lines, so that any improvements obtained would be immediately relevant to the PV industry. This investigation determined that reactive ion etching (RIE) is compatible with using standard, commercial, screen-printed gridlines as etch masks to form self-aligned, selectively doped emitter profiles. This process results in reduced gridline contact resistance when followed by plasma-enhanced chemical vapor deposition (PECVD) treatments, an undamaged emitter surface easily passivated by plasma-nitride, and a less heavily doped emitter between gridlines for reduced emitter recombination. This allows for heavier doping beneath the gridlines for even lower contact resistance, reduced contact recombination, and better bulk defect gettering. Our initial results found a statistically significant improvement of about half an absolute percentage point in cell efficiency when the self-aligned emitter etchback was combined with a PECVD-nitride surface passivation treatment. Some additional improvement in bulk diffusion length was observed when a hydrogen passivation treatment was used in the process. We attempted to gain additional benefits from using an extra-heavy phosphorus emitter diffusion before the gridlines were deposited. However, this required a higher plasma-etch power to etch back the deeper diffusion and keep the etch time reasonably short. The higher power etch may have damaged the surface and the gridlines so that improvement due to surface passivation and reduced gridline contact resistance was inhibited.

This paper is concerned with describing a damage mechanics formulation which provides for non-isotropic effects using a scalar damage variable. An investigation has been in progress for establishing the constitutive behavior of rock salt at long times and low to moderate confining pressures in relation to the possible use of excavated rooms in rock salt formations as repositories for nuclear waste. An important consideration is the effect of damage manifested principally by the formation of shear induced wing cracks which have a stress dependent orientation. The analytical formulation utilizes a scalar damage parameter, but is capable of indicating the non-isotropic dependence of inelastic straining on the stress state and the confining pressure. Also, the equations indicate the possibility of volumetric expansions leading to the onset of tertiary creep and eventually rupture if the damage variable reaches a critical value.

The interactions of CP-Ti and Ti-6Al-4V with investment molds containing alumina/silica and yttria/silica face coat systems were studied. "Containerless" melting in argon was employed and small test samples were made by drop casting into the molds. The effects of the face coat material and mold preheat temperatures on the thickness of the alpha case in the drop castings were evaluated with microhardness and microprobe measurements. It was found that the thickness of the alpha case was the same, whether a yttria/silica or alumina/silica face coat was used, indicating that the silica binder can reduce the apparent inertness of a more stable refractory, such as yttria. It was also found that the alloyed titanium castings had a thinner alpha case than those produced from CP-Ti, which suggests that the thickness of the alpha case depends on the crystal structure of the alloy during cooling from high temperatures. Furthermore, the small drop castings made in small yttria crucibles used as molds exhibited little or no alpha case.

The nuclear microprobe has proven to be a useful tool in radiation testing of integrated circuits. This paper reviews single event upset and ion beam induced charge collection imaging techniques, with special attention to damage-dependent effects. Comparisons of charge collection measurements with three-dimensional charge transport simulations of charge collection are then presented for isolated p-channel field effect transistors under conducting and non-conducting bias conditions.

This article attempts to review the progress achieved in the understanding of scaling and size effect in the failure of structures. Particular emphasis is placed on quasibrittle materials for which the size effect is important and complicated. After reflections on the long history of size effect studies, attention is focused on three main types of size effects, namely the statistical size effect due to randomness of strength, the energy release size effect, and the possible size effect due to fractality of fracture or microcracks. Definitive conclusions on the applicability of these theories are drawn. Subsequently, the article discusses the application of the known size effect law for the measurement of material fracture properties, and the modeling of the size effect by the cohesive crack model, nonlocal finite element models and discrete element models. Extensions to compression failure and to the rate-dependent material behavior are also outlined. The damage constitutive law needed for describing a microcracked material in the fracture process zone is discussed. Various applications to quasibrittle materials, including concrete, sea ice, fiber composites, rocks and ceramics are presented. There are 377 references included in this article. © 1997 American Society of Mechanical Engineers.

Two methods were examined for the fabrication of dielectric mirror masks. In the first method, a commercial laser mirror was patterned with photoresist and the dielectric film etched with ammonium bifluoride. The ammonium bifluoride etch showed strong kinetic anisotropy with the fastest etch rate in the vertical direction. However, horizontal etching still resulted in significant undercutting of the photomask. In the second method, a photoresist coated laser mirror was etched with an argon plasma. The argon plasma caused significant damage to the photoresist and underlying dielectric layer without adequate removal of the dielectric film in the open areas of the mask. Neither of the two methods examined were able to produce usable dielectric masks. During the course of this project, it was discovered that a foreign company, Balzers AG of Liechtenstein, had recently developed successful fabrication procedures for dielectric mirror masks. A mask purchased from Balzers for testing showed distinguishable pattern features down to 2 {mu}m in size. This mask was used in ablative projection etching experiments to form microstructures in Mylar polymer films. A thin film resistor pattern with 7.0 {mu}m wide lines was etched 5.4 {mu}m deep into a Mylar substrate. The etch pattern showed uniform linewidths but exhibited some thinning of the lines in areas where U-turns occurred. The ablative projection etching technique shows promise as a method for the rapid fabrication of contact masks in microstructuring applications.

A fatigue test of a wind turbine blade was conducted at the National Renewable Energy Laboratory. Acoustic emission monitoring of the test was performed, starting with the second loading level. The acoustic emission data showed that this load exceeded the strength of the blade. An oil can type of deformation was seen in two areas of the upper skin of the blade from the beginning of the second loading. One was near the blade root and the other was at about 35% of the span. The acoustic emission data indicated that no damage was taking place near the root, but in the deforming area at 35% span, damage occurred from the first cycles of the second load. The test was stopped after approximately one day, although no gross damage had occurred. Several weeks later the test was resumed. Gross damage occurred in approximately one half hour. The emission data showed evidence of a possible second damage site. © 1997, American Institute of Aeronautics and Astronautics, Inc.

Quartz crystal microbalances (QCMs) are piezoelectric thickness-shear-mode resonators where the resonant frequency has long been known to vary linearly with the mass of rigid layers on the surface when the device is in contact with air. This reports summarizes the results from a Laboratory Directed Research and Development effort to use an array of QCMs to measure and identify volatile organic compounds (VOCs) in water solutions. A total of nine polymer-coated QCMs were tested with varying concentrations of twelve VOCs while frequency and damping voltage were measured. Results from these experiments were analyzed using a Sandia-developed pattern recognition technique called visually empirical region of influence (VERI) developed at Sandia. The VERI analyses of data with up to 16% and 50% sensitivity drifts were carried out on an array with six signals obtained from five sensors. The results indicate that better than 98% and 88% correct chemical recognition is maintained for the 16% and 50% drifts, respectively. These results indicate a good degree of robustness for these sensor films.

Mid-infrared lasers grown by MOCVD with AlAsSb claddings and strained InAsSb active regions are reported. A 3.8-3.9 μm injection laser with a pseudomorphic InAsSb multiple quantum well active region lased at 210 K under pulsed operation. A semi-metal layer acts as an internal electron source for the injection laser. An optically pumped laser with an InAsSb/InAsP strained-layer superlattice active region was demonstrated at 3.7 μm, 240 K.

Ion implantation doping and isolation is expected to play an enabling role for the realization of advanced III-Nitride based devices. In fact, implantation has already been used to demonstrate n- and p-type doping of GaN with Si and Mg or Ca, respectively, as well as to fabricate the first GaN junction field effect transistor. Although these initial implantation studies demonstrated the feasibility of this technique for the III-Nitride materials, further work is needed to realize its full potential. After reviewing some of the initial studies in this field, we present new results for improved annealing sequences and defect studies in GaN. First, sputtered AlN is shown by electrical characterization of Schottky and Ohmic contacts to be an effective encapsulant of GaN during the 1100°C implant activation anneal. The AlN suppresses N-loss from the GaN surface and the formation of a degenerate n+-surface region that would prohibit Schottky barrier formation after the implant activation anneal. Second, we examine the nature of the defect generation and annealing sequence following implantation using both Rutherford Backscattering (RBS) and Hall characterization. We show that for a Si-dose of 1 × 1016 cm-2 50% electrical donor activation is achieved despite a significant amount of residual implantation-induced damage in the material.

The wide band gap group-III nitride materials continue to generate interest in the semiconductor community with the fabrication of green, blue, and ultraviolet light emitting diodes (LEDs), blue lasers, and high temperature transistors. Realization of more advanced devices requires pattern transfer processes which are well controlled, smooth, highly anisotropic and have etch rates exceeding 0.5 μm/min. The utilization of high-density chlorine-based plasmas including electron cyclotron resonance (ECR) and inductively coupled plasma (ICP) systems has resulted in improved etch quality of the group-III nitrides over more conventional reactive ion etch (RIE) systems.

Many applications of high temperature superconductors, HTS, require the presence of lattice defects in the material structure to suppress the motion of magnetic vortices and enhance the critical current density, Jc. The microstructure of Tl2Ba2CaCu2O8-δ (Tl-2212) thin films which have extended defects induced by high energy Au and Cu ion irradiation is studied using high resolution transmission electron microscopy, HRTEM, with slow scan digital imaging. In order to optimize the HTS properties and better analyze the consequent microstructural modification, the fluence is varied. At moderate fluences, resulting in approximately 4% reduction of the superconducting transition, large enhancements of Jc and vortex pinning potential are observed. The density and microstructure of isolated defects and surrounding structure will be discussed and compared to damage profiles calculated using the TRIM code. Correlation will be made between the HRTEM results and the changes in HTS properties.

Optically targeted, ion microbeams provide a useful means of exposing individual structures within an integrated circuit to ionizing radiation. With this tool, calibrated, low damage, charge collection spectra can be measured from specific circuit structures without preceding ion damage to the structure or surrounding circuitry. This paper presents comparisons of calibrated, low damage, ion microbeam-based charge collection measurements and three-dimensional, charge transport simulations of charge collection for isolated n-and p-channel field effect transistors under conducting and non-conducting bias conditions.

Understanding the mechanisms that impact the performance of Microelectromechanical Systems (MEMS) is essential to the development of optimized designs and fabrication processes, as well as the qualification of devices for commercial applications. Silicon micromachines include engines that consist of orthogonally oriented linear comb drive actuators mechanically connected to a rotating gear. These gears are as small as 50 {mu}m in diameter and can be driven at rotation rates exceeding 300,000 rpm. Optical techniques offer the potential for measuring long term statistical performance data and transient responses needed to optimize designs and manufacturing techniques. We describe the development of Micromachine Optical Probe (MOP) technology for the evaluation of micromachine performance. The MOP approach is based on the detection of optical signals scattered by the gear teeth or other physical structures. We present experimental results obtained with a prototype optical probe and micromachines developed at Sandia National Laboratories.

We frequently develop mathematical models of system behavior and sometimes use test data to help identify the parameters of the mathematical model. However, no general-purpose technique exists for formally, statistically judging the quality of a model. This paper suggests a formal statistical procedure for the validation of mathematical models of systems when data taken during operation of the system are available. The statistical validation procedure is based on the bootstrap, and it seeks to build a framework where a statistical test of hypothesis can be run to determine whether or not a mathematical model is an acceptable model of a system with regard to user-specified measures of system behavior. A numerical example is presented to demonstrate the application of the technique.

Vector network analyzers provide a convenient way to measure scattering parameters of a variety of microwave devices. However, these instruments, unlike oscilloscopes for example, require a relatively high degree of user knowledge and expertise. Due to the complexity of the instrument and of the calibration process, there are many ways in which an incorrect measurement may be produced. We routinely use check standards to verify that the network analyzer is operating properly. In the past, these measurements were recorded manually and, sometimes, interpretation of the results was problematic. To aid our measurement assurance, a software program was developed to automatically measure a check standard and compare the new measurements with an historical database of measurements of the same device. The program acquires new measurement data from selected check standards, plots the new data against the mean and standard deviation of prior data for the check standard, and updates the database files for the check standard. The program is entirely menu-driven requiring little additional work by the user. This paper describes the function of the software, including a discussion of its capabilities, and the way in which the software is used in our lab. Finally, some examples are given showing how the software can detect potential measurement problems.

A method for more efficiently utilizing the frequency bandwidth allocated for data transmission is presented. Current space and range communication systems use modulation and coding schemes that transmit 0.5 to 1.0 bits per second per Hertz of radio frequency bandwidth. The goal in this LDRD project is to increase the bandwidth utilization by employing advanced digital communications techniques. This is done with little or no increase in the transmit power which is usually very limited on airborne systems. Teaming with New Mexico State University, an implementation of trellis coded modulation (TCM), a coding and modulation scheme pioneered by Ungerboeck, was developed for this application and simulated on a computer. TCM provides a means for reliably transmitting data while simultaneously increasing bandwidth efficiency. The penalty is increased receiver complexity. In particular, the trellis decoder requires high-speed, application-specific digital signal processing (DSP) chips. A system solution based on the QualComm Viterbi decoder and the Graychip DSP receiver chips is presented.

Electrokinetic remediation of uranium-contaminated soil was studied in a series of laboratory-scale experiments in test cells with identical geometry using quartz sand at approximately 10 percent moisture content. Uranium, when present in the soil system as an anionic complex, could be migrated through unsaturated soil using electrokinetics. The distance that the uranium migrated in the test cell was dependent upon the initial molar ratio of citrate to uranium used. Over 50 percent of the uranium was recovered from the test cells using the citrate and carbonate complexing agents over of period of 15 days. Soil analyses showed that the uranium remaining in the test cells had been mobilized and ultimately would have been extracted. Uranium extraction exceeded 90 percent in an experiment that was operated for 37 days. Over 70 percent of the uranium was removed from a Hanford waste sample over a 55 day operating period. Citrate and carbonate ligand utilization ratios required for removing 50 percent of the uranium from the uranium-contaminated sand systems were approximately 230 moles ligand per mole uranium and 1320 moles ligand per mole uranium for the waste. Modifying the operating conditions to increasing the residence time of the complexants is expected to improved the utilization efficiency of the complexing agent.

Tera Computer and Sandia National Laboratories have completed a CRADA, which examined the Tera Multi-Threaded Architecture (MTA) for use with large codes of importance to industry and DOE. The MTA is an innovative architecture that uses parallelism to mask latency between memories and processors. The physical implementation is a parallel computer with high cross-section bandwidth and GaAs processors designed by Tera, which support many small computation threads and fast, lightweight context switches between them. When any thread blocks while waiting for memory accesses to complete, another thread immediately begins execution so that high CPU utilization is maintained. The Tera MTA parallel computer has a single, global address space, which is appealing when porting existing applications to a parallel computer. This ease of porting is further enabled by compiler technology that helps break computations into parallel threads. DOE and Sandia National Laboratories were interested in working with Tera to further develop this computing concept. While Tera Computer would continue the hardware development and compiler research, Sandia National Laboratories would work with Tera to ensure that their compilers worked well with important Sandia codes, most particularly CTH, a shock physics code used for weapon safety computations. In addition to that important code, Sandia National Laboratories would complete research on a robotic path planning code, SANDROS, which is important in manufacturing applications, and would evaluate the MTA performance on this code. Finally, Sandia would work directly with Tera to develop 3D visualization codes, which would be appropriate for use with the MTA. Each of these tasks has been completed to the extent possible, given that Tera has just completed the MTA hardware. All of the CRADA work had to be done on simulators.

Multichip modules (MCMs) containing power components need a substrate with excellent heat spreading capability to both avoid hot spots and to move dissipation heat toward the system heat sinks. Polycrystalline diamond is an excellent MCM heat spreading substrate but remains several orders of magnitude too expensive and somewhat more difficult to process than conventional mother-board materials. Today`s power MCMs concentrate on moderately priced silicon wafers and aluminum nitride ceramic with their improved thermal conductivity and good thermal expansion match to power semiconductor components in comparison to traditional alumina and printed wiring board materials. However, even silicon and AlN substrates are thermally challenged by designers needs. The authors report on the integral fabrication of micro-heat pipes embedded in silicon MCM substrates (5 x 5 cm) by the use of micromachined capillary wick structures and hermetic micro-cavities. This passive microstructure results in more than a 5 times improvement in heat spreading capability of the silicon MCM substrate over a large range of power densities and operating temperatures. Thus diamond-like cooling is possible at silicon prices.

Detecting object boundaries in the presence of cast shadows is a difficult task for machine vision systems. A new edge detector is presented which responds to shadow penumbras and abrupt object edges with distinguishable signals. The detector requires the use of spatially extended light sources and sufficient video resolution to resolve the shadow penumbras of interest. Detection of high frequency noise is suppressed without requiring image-dependent adjustment of signal thresholds. The ability of the edge operator to distinguish shadow penumbras from abrupt object boundaries while suppressing responses to high frequency noise and texture is illustrated with idealized shadow and object edge intensity profiles. Selective detection of object boundaries in a video scene with a cast shadow has also been demonstrated with this operator.

Modular fixturing kits are precisely machined sets of components used for flexible, short-turnaround construction of fixtures for a variety of manufacturing purposes. A modular vise is a parallel-jaw vise, where each jaw is a modular fixture plate with a regular grid of precisely positioned holes. A modular vise can be used to locate and hold parts for machining, assembly, and inspection tasks. To fixture a part, one places pins in some of the holes so that when the vise is closed, the part is reliably located and completely constrained. The modular vise concept can be adapted easily to the design of modular parallel-jaw grippers for robots. By attaching a grid plate to each jaw of a parallel-jaw gripper, the authors gain the ability to easily construct high-quality grasps for a wide variety of parts from a standard set of hardware. Wallack and Canny developed a previous algorithm for planning planar grasp configurations for the modular vise. In this paper, the authors expand this work to produce a 3-d fixture/gripper design tool. They describe several analyses added to the planar algorithm to improve its utility, including a three-dimensional grasp quality metric based on geometric and force information, three-dimensional geometric loading analysis, and inter-gripper interference analysis to determine the compatibility of multiple grasps for handing the part from one gripper to another. Finally, the authors describe two applications which combine the utility of modular vise-style grasping with inter-gripper interference: The first is the design of a flexible part-handling subsystem for a part cleaning workcell under development at Sandia National Laboratories; the second is the automatic design of grippers that support the assembly of multiple products on a single assembly line.

The goal of the Modular Weapon Control Unit (MWCU) program was to design and develop a reconfigurable weapon controller (programmer/sequencer) that can be adapted to different weapon systems based on the particular requirements for that system. Programmers from previous systems are conceptually the same and perform similar tasks. Because of this commonality and the amount of re-engineering necessary with the advent of every new design, the idea of a modular, adaptable system has emerged. Also, the controller can be used in more than one application for a specific weapon system. Functionality has been divided into a Processor Module (PM) and an Input/Output Module (IOM). The PM will handle all operations that require calculations, memory, and timing. The IOM will handle interfaces to the rest of the system, input level shifting, output drive capability, and detection of interrupt conditions. Configuration flexibility is achieved in two ways. First, the operation of the PM is determined by a surface mount Read-Only Memory (ROM). Other surface-mount components can be added or neglected as necessary for functionality. Second, IOMs consist of configurable input buffers, configurable output drivers, and configurable interrupt generation. Further, these modules can be added singly or in groups to a Processor Module to achieve the required I/O configuration. The culmination of this LDRD was the building of both Processor Module and Input/Output Module. The MWCU was chosen as a test system to evaluate Low-Temperature Co-fired Ceramic (LTCC) technology, desirable for high component density and good thermal characteristics.

A series of three 18.9 m diameter JP-4 pool fire experiments with a large (2.1 m X 4.6 m), flat plate calorimeter adjacent to the fuel pool were recently performed. The objectives of these experiments were to: (1) gain a better understanding of fire phenomenology, (2) provide empirical input parameter estimates for simplified, deterministic Risk Assessment Compatible Fire Models (RACFMs), (3) assist in continuing fire field model code validation and development, and (4) enhance the data base of fire temperature and heat flux to object distributions. Due to different wind conditions during each experiment, data were obtained for conditions where the plate was not engulfed, fully-engulfed and partially engulfed by the continuous flame zone. Results include the heat flux distribution to the plate and flame thermocouple temperatures in the vicinity of the plate and at two cross sections within the lower region of the continuous flame zone. The results emphasize the importance of radiative coupling (i.e. the cooling of the flames by a thermally massive object) and convective coupling (including object-induced turbulence and object/wind/flame interactions) in determining the heat flux from a fire to an object. The formation of a secondary flame zone on an object adjacent to a fire via convective coupling (which increases the heat flux by a factor of two) is shown to be possible when the object is located within a distance equal to the object width from the fire.

This study involved the evaluation and documentation of cases in which petroleum wellbores were enlarged beyond the nominal hole diameter as a consequence of erosion during exploratory drilling, particularly as a function of gas flow into the wellbore during blowout conditions. A primary objective was to identify analogs to potential wellbore enlargement at the Waste Isolation Pilot Plant (WIPP) during inadvertent human intrusion. Secondary objectives were to identify drilling scenarios associated with enlargement, determine the physical extent of enlargement, and establish the physical properties of the formation in which the enlargement occurred. No analogs of sufficient quality to establish quantitative limits on wellbore enlargement at the WIPP disposal system were identified. However, some information was obtained regarding the frequency of petroleum well blowouts and the likelihood that such blowouts would bridge downhole, self-limiting the surface release of disposal-system material. Further work would be necessary, however, to determine the conditions under which bridging could occur and the extent to which the bridging might be applicable to WIPP. In addition, data on casing sizes of petroleum boreholes in the WIPP vicinity support the use of a 12-{1/4} inch borehole size in WIPP performance assessment calculations. Finally, although data are limited, there was no evidence of significant wellbore enlargement in any of three blowouts that occur-red in wellbores in the Delaware Basin (South Culebra Bluff Unit No. 1, Energy Research and Development Administration (ERDA) 6, and WIPP 12).

This report contains a condensed listing of Waste Isolation Pilot Plant (WIPP) project surface boreholes drilled for the purpose of site selection and characterization through 31 December 1995. The US Department of Energy (DOE) sponsored the drilling activities, which were conducted primarily by Sandia National Laboratories. The listing provides physical attributes such as location (township, range, section, and state-plane coordinates), elevation, and total borehole depth, as well as the purpose for the borehole, drilling dates, and information about extracted cores. The report also presents the hole status (plugged, testing, monitoring, etc.) and includes salient findings and references. Maps with borehole locations and times-of-drilling charts are included.

Energetic materials, such as high explosives, propellants and ballotechnics, are widely used as energy sources in the design of numerous devices, components and processes. Although most energetic materials are selected for safe operation, their high energy densities have the potential for inadvertent initiation and subsequent powerful energy transformations. This potential for damage or injury places a heavy burden on careful analysis of safety issues as part of the design process. As a result, considerable effort has been devoted to empirical testing of initiation conditions, and development of scientific models of initiation processes that have been incorporated into computer models for numerical simulation of initiation of reaction. Nevertheless, in many cases, there is still only rudimentary understanding of the processes of initiation. Mechanochemical processes are perhaps the least understood of the various excitation mechanisms. In these energy transformation processes mechanical stimuli lead directly to initiation and substantial reaction under conditions not thought to be capable of reaction. There are no established scientific models of the initiation of mechanochemical reactions in energetic materials. Mechanochemical reactions can be initiated by enhanced solid state chemical reactivity, changes in reactant configuration, and localization of initiation energy. Such solid state reactions are difficult to understand, either empirically or scientifically, as they are inherently nonequilibrium processes; scientific models currently used assume equilibrium thermochemical conditions and materials behaviors. The present work was undertaken as a first step in developing a scientific basis for prediction of the initiation of mechanochemical processes in high energy density solids.

Networks at major computational organizations are becoming increasingly complex. The introduction of large massively parallel computers and supercomputers with gigabyte memories are requiring greater and greater bandwidth for network data transfers to widely dispersed clients. For networks to provide adequate data transfer services to high performance computers and remote users connected to them, the networking components must be optimized from a combination of internal and external performance criteria. This paper describes research done at Sandia National Laboratories to model network data services and to visualize the flow of data from source to sink when using the data services.

The Hierarchical High-Performance Storage System (HPSS) Testbed project at Sandia National Laboratories was part of a research collaboration between industry, national research centers, and national laboratories to develop mass storage system software that would scale to meet the capacity and performance required by supercomputer and massively parallel computational environments. This report describes the software that was developed within this collaboration as a result of a cooperative research and development agreement between Sandia National Laboratories and International Business Machines (IBM) Corporation, Government Systems.

We report results in three areas of research relevant to the fabrication of a wide range of optoelectronic devices: The development of a new x-ray diffraction technique that can be used to rapidly determine the optimal period of a strained layer superlattice to maximize the dislocation filtering; The optimal MBE growth parameters for the growth of CdTe on GaAs(211); The determination of the relative efficiency of dislocation filtering in the (211) and (100) orientations; and The surface quality of InSb grown by MOCVD on InSb substrates is affected by the misorientation of the substrate.

This report describes the information model that was jointly developed as part of two FY93 LDRDs: (1) Information Integration for Data Fusion, and (2) Interactive On-Site Inspection System: An Information System to Support Arms Control Inspections. This report describes the purpose and scope of the two LDRD projects and reviews the prototype development approach, including the use of a GIS. Section 2 describes the information modeling methodology. Section 3 provides a conceptual data dictionary for the OSIS (On-Site Information System) model, which can be used in conjunction with the detailed information model provided in the Appendix. Section 4 discussions the lessons learned from the modeling and the prototype. Section 5 identifies the next steps--two alternate paths for future development. The long-term purpose of the On-Site Inspection LDRD was to show the benefits of an information system to support a wide range of on-site inspection activities for both offensive and defensive inspections. The database structure and the information system would support inspection activities under nuclear, chemical, biological, and conventional arms control treaties. This would allow a common database to be shared for all types of inspections, providing much greater cross-treaty synergy.

An improved capability for subsurface structure detection is needed to support military and nonproliferation requirements for inspection and for surveillance of activities of threatening nations. As part of the DOE/NN-20 program to apply geophysical methods to detect and characterize underground facilities, Sandia National Laboratories (SNL) initiated an electromagnetic induction (EMI) project to evaluate low frequency electromagnetic (EM) techniques for subsurface structure detection. Low frequency, in this case, extended from kilohertz to hundreds of kilohertz. An EMI survey procedure had already been developed for borehole imaging of coal seams and had successfully been applied in a surface mode to detect a drug smuggling tunnel. The SNL project has focused on building upon the success of that procedure and applying it to surface and low altitude airborne platforms. Part of SNL`s work has focused on improving that technology through improved hardware and data processing. The improved hardware development has been performed utilizing Laboratory Directed Research and Development (LDRD) funding. In addition, SNL`s effort focused on: (1) improvements in modeling of the basic geophysics of the illuminating electromagnetic field and its coupling to the underground target (partially funded using LDRD funds) and (2) development of techniques for phase-based and multi-frequency processing and spatial processing to support subsurface target detection and characterization. The products of this project are: (1) an evaluation of an improved EM gradiometer, (2) an improved gradiometer concept for possible future development, (3) an improved modeling capability, (4) demonstration of an EM wave migration method for target recognition, and a demonstration that the technology is capable of detecting targets to depths exceeding 25 meters.

Data fusion has been identified by the Department of Defense as a critical technology for the U.S. defense industry. Data fusion requires combining expertise in two areas - sensors and information integration. Although data fusion is a rapidly growing area, there is little synergy and use of common, reusable, and/or tailorable objects and models, especially across different disciplines. The Laboratory-Directed Research and Development project had two purposes: to see if a natural language-based information modeling methodology could be used for data fusion problems, and if so, to determine whether this methodology would help identify commonalities across areas and achieve greater synergy. The project confirmed both of the initial hypotheses: that the natural language-based information modeling methodology could be used effectively in data fusion areas and that commonalities could be found that would allow synergy across various data fusion areas. The project found five common objects that are the basis for all of the data fusion areas examined: targets, behaviors, environments, signatures, and sensors. Many of the objects and the specific facts related to these objects were common across several areas and could easily be reused. In some cases, even the terminology remained the same. In other cases, different areas had their own terminology, but the concepts were the same. This commonality is important with the growing use of multisensor data fusion. Data fusion is much more difficult if each type of sensor uses its own objects and models rather than building on a common set. This report introduces data fusion, discusses how the synergy generated by this LDRD would have benefited an earlier successful project and contains a summary information model from that project, describes a preliminary management information model, and explains how information integration can facilitate cross-treaty synergy for various arms control treaties.

Rock cores from drillholes UE25-NRG-4, USW-NRG-6, USW-NRG-7, and USW-SD-9 containing natural fractures were obtained from the Sample Management Facility at Yucca Mountain, Nevada. All recoverable fractures were sheared at constant normal stresses from 2.5 to 15 MPa, in the as-received condition (air-dry). Detailed profilometer data were collected from each fracture surface before testing. The tests yielded the normal closure as a function of normal stress, and the shear stress and dilation as functions of shear offset. The constitutive properties obtained from these stress-displacement relations were: normal stiffness, shear stiffness, shear strength, and dilation angle at peak shear stress. Shear strength plotted against normal stress for four thermomechanical units shows that friction angle varies from 370 to 460 and cohesion varies from 0.02 to 1.71 MPa.

This report provides an overview of the work completed for a portion of the User Interface Testbed for Technology Packaging (UseIT) project. The authors present software methods for programming systems to record and view interactions with a graphical user interface. A brief description of the human factors design process is presented. The software methods exploit features available in the X Window System and the operating system for Windows{trademark} 95 and Windows{trademark} NT{reg_sign}.

Work on thermionic nuclear power systems has been performed in Russia within the framework of the TOPAZ reactor program since the early 1960s. In the TOPAZ in-core thermionic convertor reactor design, the fuel element`s cladding is also the thermionic convertor`s emitter. Deformation of the emitter can lead to short-circuiting and is the primary cause of premature TRC failure. Such deformation can be the result of fuel swelling, thermocycling, or increased unilateral pressure on the emitter due to the release of gaseous fission products. Much of the work on TRCs has concentrated on preventing or mitigating emitter deformation by improving the following materials and structures: nuclear fuel; emitter materials; electrical insulators; moderator and reflector materials; and gas-exhaust device. In addition, considerable effort has been directed toward the development of experimental techniques that accurately mimic operational conditions and toward the creation of analytical and numerical models that allow operational conditions and behavior to be predicted without the expense and time demands of in-pile tests. New and modified materials and structures for the cores of thermionic NPSs and new fabrication processes for the materials have ensured the possibility of creating thermionic NPSs for a wide range of powers, from tens to several hundreds of kilowatts, with life spans of 5 to 10 years.

This report summarizes the work performed under the Sandia Laboratory Directed Research and Development (LDRD) project ``Optical Diagnostics for Turbulent and Multiphase Flows.`` Advanced optical diagnostics have been investigated and developed for flow field measurements, including capabilities for measurement in turbulent, multiphase, and heated flows. Particle Image Velocimetry (PIV) includes several techniques for measurement of instantaneous flow field velocities and associated turbulence quantities. Nonlinear photorefractive optical materials have been investigated for the possibility of measuring turbulence quantities (turbulent spectrum) more directly. The two-dimensional PIV techniques developed under this LDRD were shown to work well, and were compared with more traditional laser Doppler velocimetry (LDV). Three-dimensional PIV techniques were developed and tested, but due to several experimental difficulties were not as successful. The photorefractive techniques were tested, and both potential capabilities and possible problem areas were elucidated.

This Phase 1 report documents the results of one of the subtasks that was initiated under the joint Department of Energy (DOE)/Department of Defense (DoD) Memorandum of Understanding (MOU) for Countermine Warfare. The development of a foam that can neutralize mines and barriers and allow the safe passage of amphibious landing craft and vehicles was the objective of this subtask of the Sea Mine Countermeasures Technology program. This phase of the program concentrated on laboratory characterization of foam properties and field experiments with prefabricated foam blocks to determine the capability of RPF to adequately carry military traffic. It also established the flammability characteristics of the material under simulated operational conditions, extended the understanding of explosive cavity formation in RPF to include surface explosions, established the tolerance to typical military fluids, and the response to bullet impact. Many of the basic analyses required to establish the operational concept are reported. The initial field experiments were conducted at the Energetic Materials Research and Testing Center (EMRTC) of the New Mexico Institute of Mining and Technology, Socorro, NM in November 1995 through February 1996.

The development and initial evaluation of a prototype boring bar feature active vibration control for increased chatter immunity is described. The significance of active damping both normal and tangential to the workpiece surface is evaluated, indicating the need for two axis control to ensure adequate performance over expected variations in tool mounting procedures. The prototype tool features a commercially available boring bar modified to accommodate four PZT stack actuators for two axis bending control. Measured closed-loop dynamics are combined with a computer model of the boring process to simulate increased metal removal rate and improved workpiece surface finish through application of feedback control.

VRaptor, a VR system for situational training that uses trainer-defined scenarios is described. The trainee is represented by an avatar; the rest of the virtual world is populated by virtual actors, which are under the control of trainer-defined scripts. The scripts allow reactive behaviors, but the trainer can control the overall scenario. This type of training system may be very useful in supplementing physical training.

The design of complex systems is difficult at best, but as a design becomes intensively dependent on the computer processing of external and internal information, the design process quickly borders chaos. This situation is exacerbated with the requirement that these systems operate with a minimal quantity of information, generally corrupted by noise, regarding the current state of the system. Establishing performance requirements for such systems is particularly difficult. This paper briefly sketches a general systems design approach with emphasis on the design of computer based decision processing systems subject to parameter and environmental variation. The approach will be demonstrated with application to an on-board diagnostic (OBD) system for automotive emissions systems now mandated by the state of California and the Federal Clean Air Act. The emphasis is on developing approach for establishing probabilistically based performance requirements for computer based systems.

The goal is to provide a high level of confidence that critical software driven event sequences are maintained in the face of hardware failures and harsh or unstable operating environments. The technical approach includes in-situ (embedded in the software) dynamic (run-time) fault management for ensuring critical event sequences in high consequence software. Our method is based on deriving a mathematical description of the critical software controlled event sequence, embedding check points and update points around the critical events into the target code, and adding a module that implements the functionality of the underlying mathematical model. This methodology is inspired by previous work in path expressions. This paper discusses the perceived problems, a brief overview of path expressions, the proposed methods, and a discussion of the differences between the proposed methods and traditional path expression usage and implementation.

Fast Z-pinch implosions can efficiently convert the stored electrical energy in a pulsed-power accelerator into x rays. These x rays are produced when an imploding cylindrical plasma, driven by the magnetic field pressure associated with very large axial currents, stagnates upon the cylindrical axis of symmetry. On the Saturn pulsed-power accelerator [R. B. Spielman et al., in Proceedings of the 2nd International Conference on Dense Z Pinches, Laguna Beach, CA, 1989, edited by N. R. Pereira, J. Davis, and N. Rostoker (American Institute of Physics, New York, 1989), p. 3] at Sandia National Laboratories, for example, currents of 6–8 MA with a rise time of less than 50 ns are driven through cylindrically symmetric loads, producing implosion velocities as high as [formula omitted] and x-ray energies exceeding 400 kJ. Hydromagnetic Rayleigh–Taylor instabilities and cylindrical load symmetry are critical, limiting factors in determining the assembled plasma densities and temperatures, and thus in the x-ray energies and pulse widths that can be produced on these accelerators. In recent experiments on the Saturn accelerator, these implosion nonuniformities have been minimized by using wire arrays with as many as 192 wires. Increasing the wire number produced significant improvements in the pinched plasma quality, reproducibility, and x-ray output power. X-ray pulse widths of less than 5 ns and peak powers of [formula omitted] have been achieved with arrays of 120 tungsten wires. Similar loads have recently been fielded on the Particle Beam Fusion Accelerator (PBFA II), producing x-ray energies in excess of 1.8 MJ at powers in excess of 160 TW. These intense x-ray sources offer the potential for performing many new basic physics and fusion-relevant experiments. © 1997, American Institute of Physics. All rights reserved.

The Downhole Dynamometer Database is a compilation of test data collected with a set of five downhole tools built by Albert Engineering under contract to Sandia National Laboratories. The downhole dynamometer tools are memory tools deployed in the sucker rod string with sensors to measure pressure, temperature, load, and acceleration. The acceleration data is processed to yield position, so that a load vs. position dynagraph can be generated using data collected downhole. With five tools in the hole at one time, all measured data and computed dynagraphs from five different positions in the rod string are available. The purpose of the Database is to provide industry with a complete and high quality measurement of downhole sucker rod pumping dynamics. To facilitate use of the database, Sandia has developed a Microsoft Windows-based interface that functions as a visualizer and browser to the more than 40 MBytes of data. The interface also includes a data export feature to allow users to extract data from the database for use in their own programs. This paper includes a description of the downhole dynamometer tools, data collection program, database content, and a few illustrations of the data contained in the downhole dynamometer database.

Constraints on assembly plans vary depending on product, assembly facility, assembly volume, and many other factors. This paper describes the principles and implementation of a framework that supports a wide variety of user-specified constraints for interactive assembly planning. Constraints from many sources can be expressed on a sequencing level, specifying orders and conditions on part mating operations in a number of ways. All constraints are implemented as filters that either accept or reject assembly operations proposed by the planner. For efficiency, some constraints are supplemented with special-purpose modifications to the planner's algorithms. Fast replanning enables a natural plan-view-constrain-replan cycle that aids in constraint discovery and documentation. We describe an implementation of the framework in a computer-aided assembly planning system and experiments applying the system to several complex assemblies.

A system for automatic tool path generation was developed at Sandia National Laboratories for finish machining operations. The system consists of a commercially available 5-axis milling machine controlled by Sandia developed software. This system was used to remove overspray on cast turbine blades. A laser-based, structured-light sensor, mounted on a tool holder, is used to collect 3D data points around the surface of the turbine blade. Using the digitized model of the blade, a tool path is generated which will drive a 0.375″ CBN grinding pin around the tip of the blade. A fuzzified digital filter was developed to properly eliminate false sensor readings caused by burrs, holes and overspray. The digital filter was found to successfully generate the correct tool path for a blade with intentionally scanned holes and defects. The fuzzified filter improved the computation efficiency by a factor of 25. For application to general parts, an adaptive scanning algorithm was developed and presented with simulation results. A right pyramid and an ellipsoid were scanned successfully with the adaptive algorithm.

A tool using a continuous electromagnetic wave from a transverse magnetic-dipole source with a coaxial electric-dipole receiver is outlined for the detection of external sidewall cracks in boiler tubes. A numerical study of the distribution of the fields shows that the direct transmission from the source to the receiver is reduced from that in free space. Further, if the diameter of the receiver dipole is made sufficiently small, it should be possible to detect cracks with a scattering loss of up to 40dB in thin-walled boiler tubes.

We discuss the integration of the SANDROS path planner into a general robot simulation and control package with the inclusion of a fast geometry engine for distance calculations. This creates a single system that allows the path to be computed, simulated, and then executed on the physical robot. The architecture and usage procedures are presented. Also, we present examples of its usage in typical environments found in our organization. The resulting system is as easy to use as the general simulation system (which is in common use here) and is fast enough (example problems are solved in seconds) to be used interactively on an everyday basis.

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 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.

A compact optoelectronic integrated circuit (OEIC) for generation of millimeter-wave frequencies was demonstrated. It integrates a passively modelocked semiconductor ring laser, optical amplifier and high-speed photodiode for generation, amplification and detection of an optical pulse train with 30 to 90 GHz pulse-repetition frequency. This OEIC concept can be used in a wide variety of applications that require a very compact, light weight millimeter-wave source.

Microfluidic chips have the potential to be useful in bioanalytical tools for DNA, protein, and cellular studies. To realize this potential, means for introducing fluids, separating their components, and detection must be integrated in onto the chip. Semiconductor laser microcavity spectroscopy is investigated as a means for ultrasensitive detection of various fluids, cells, and particulates. Two methods for implementing this laser device, the spectra for four different types of cells, and how the transverse mode spacings can be used to caliper the cell dimensions are discussed. The current investigations of different methods for pumping fluids through the microactivity space using mechanical or electromotive forces are also discussed.

Sandia National Laboratories has developed a chip scale packaging technology called mini Ball Grid Array (mBGA). The mBGA is a flip chip die, obtained by redistributing peripheral pads in existing dies to an area array of pads 10 mils or larger in diameter with a minimum pitch of 20 mils. The peripheral pads are redistributed to area array pads using two polyimide dielectric and two metal conductor layers. mBGA can be closely tiled together on a substrate to yield a very high circuit density. In an earlier report, we presented the results on the reliability and thermal performance of mBGA on silicon and ceramic substrates. In this report, we present an mBGA cost analysis, improvement in the mBGA bump adhesion, and reliability and thermal performance of mBGA assemblies on FR-4 boards.

VRaptor, a VR system for situational training that uses trainer-defined scenarios is described. The trainee is represented by an avatar; the rest of the virtual world is populated by virtual actors, which are under the control of trainer-defined scripts. The scripts allow reactive behaviors, but the trainer can control the overall scenario. This type of training system may be very useful in supplementing physical training.

Gamma-densitometry tomography (GDT) and electrical-impedance tomography (EIT) have both been applied to a liquid-solid flow for comparison purposes. The experiment consisted of a cylinder (19 cm diameter) filled with water, in which 80 μm glass spheres were suspended by a mixer to achieve solid volume fractions of 0.01, 0.02, and 0.03. Both GDT and EIT revealed a relatively uniform distribution of solids in the measurement plane, and the average solid volume fractions from both techniques were in good agreement.

Wireline core drilling, increasingly used for geothermal exploration, employs a core-tube to capture a rock core sample during drilling. Three types of core-tube data loggers (CTDL) have been built and tested to date by Sandia national Laboratories. They are: (1) temperature-only logger, (2) temperature/inclinometer logger and (3) heat-shielded temperature/inclinometer logger. All were tested during core drilling operations using standard wireline diamond core drilling equipment. While these tools are designed for core-tube deployment, the tool lends itself to be adapted to other drilling modes and equipment. Topics covered in this paper include: (1) description on how the CTDLs are implemented, (2) the components of the system, (3) the type of data one can expect from this type of tool, (4) lessons learned, (5) comparison to its counterpart and (6) future work.

Hot electron induced degradation in 0.25 μm n-channel MOSFETs annealed in H2 or D2 containing atmospheres is reported. Threshold voltage and channel transconductance variations correlate with the growth of the interface state density evidenced by charge pumping measurements. The transistor lifetime (for a given transconductance variation) is ∼ 10-40 times shorter for H2 as opposed to D2 annealed devices.

The author presents a final report on a Laboratory-Directed Research and Development (LDRD) project, Innovative Computing for Diagnoses from Medical, Magnetic-Resonance Imaging, performed during fiscal years 1992 and 1993. The project defined a role for high-performance computing in surgery: the supercomputer can automatically summarize the three-dimensional extents of lesions and other clinically-relevant structures, and can deliver these summaries to workstation-based, augmented-reality environments at the clinical site. The author developed methods and software to make these summaries from the digital data already acquired using clinical, magnetic-resonance machines. In joint work with Albuquerque`s Department of Veterans Affairs Hospital, the author applied this work, and obtained a basis for planning, for rehearsal, and for guidance during surgery.

It is shown analytically and experimentally that, when significant densities of positive and/or negative charge are trapped in the bulk of the oxide, standard thermally stimulated current (TSC) measurements at negative gate bias may not provide accurate estimates of MOS oxide-trap charge densities. Combining TSC measurements at negative bias with capacitance-voltage (C-V) measurements allows useful, self-consistent estimates of trapped electron densities in the oxide to be obtained. However, unless one can determine whether most of the trapped electrons lie in the bulk of the oxide or in border traps, unambiguous estimates of trapped positive charge densities cannot be obtained with negative or positive bias TSC, with or without C-V measurements. Implications are discussed for charge trapping in radiation-hardened thermal oxides, SIMOX buried oxides, and bipolar base oxides. © 1997 IEEE.

The dependence of single event gate rupture (SEGR) critical field on oxide thickness is examined for gate oxides from 6 to 18 nm. Capacitor data are compared to SEGR data from full integrated circuits. A I/ECR dependence is found for critical field to rupture as a function of ion linear energy transfer (LET), consistent with earlier work for power MOSFETS with oxide thicknesses from 30 to 150 nm. More importantly, critical field to rupture increases with decreasing oxide thickness, consistent with increasing oxide breakdown field prior to heavy-ion exposure. This suggests that SEGR need not be a limiting factor as future technologies scale into the deep submicron region. However, there is a great deal of uncertainty in how voltage may scale with decreasing oxide thickness, and SEGR may continue to be a concern for devices that operate at electric fields significantly higher than 5 MV/cm. © 1997 IEEE.

Radiation-induced gain degradation is compared in two types of lateral PNP bipolar devices that are identical except for the emitter doping. The devices with heavily-doped emitters (1×1020 cm-3) degrade less than the devices with lightly-doped emitters (1×1018 cm-3). Both device types are sensitive to interface-trap formation in the oxide above the emitter-base junction and the neutral base region. In addition, the devices with lightly-doped emitters experience spreading of the depletion region into the emitter, increasing their sensitivity to total-dose irradiation. The gain degradation in both device types is due to a combination of increased base current and decreased collector current. The radiation-induced decrease in collector current is more significant for devices from this technology than for other devices studied previously. Increased gain degradation is observed in heavily-doped devices irradiated at low dose rates, but the enhanced degradation appears to be due to time-dependent effects rather than true dose-rate effects. The lightly-doped devices do not exhibit a clear dose-rate trend and the gain of these devices improves during post-irradiation annealing. © 1997 IEEE.

In large scale 3D EM inverse problems it may not be possible to directly invert a full least-squares system matrix involving model sensitivity elements. Thus iterative methods must be employed. For the inverse problem, we favor either a linear or non-linear (NL) CG scheme, depending on the application. In a NL CG scheme, the gradient of the objective function is required at each relaxation step along with a univariate line search needed to determine the optimum model update. Solution examples based on both approaches will be presented.

The method of finite differences has been employed to solve a variety of 3D electromagnetic (EM) forward problems arising in geophysical applications. Specific sources considered include dipolar and magnetotelluric (MT) field excitation in the frequency domain. In the forward problem, the EM fields are simulated using a vector Helmholtz equation for the electric field, which are approximated using finite differences on a staggered grid. To obtain the fields, a complex-symmetric matrix system of equations is assembled and iteratively solved using the quasi-minimum method (QMR) method. Perfectly matched layer (PML) absorbing boundary conditions are included in the solution and are necessary to accurately simulate fields in propagation regime (frequencies>10 MHz). For frequencies approaching the static limit (<10 KHz), the solution also includes a static-divergence correction, which is necessary to accurately simulate MT source fields and can be used to accelerate convergence for the dipolar source problem.

Light induced electron transfer (ET) from nanosize semiconductors of MoS2 to organic electron acceptors such as 2,2′-bipyridine (bpy) and methyl substituted 4,4′,5,5′-tetramethyl-2,2′-bipyridine (tmb) was studied by static and time resolved photoluminescence spectroscopy. The kinetics of ET were varied by changing the nanocluster size (the band gap), the electron acceptor, and the polarity of the solvent. MoS2 is an especially interesting semiconductor material as it is an indirect semiconductor in bulk form, and has a layered covalent bonding arrangement which is highly resistant to photocorrosion.

A miniature solid-propellant rocket motor has been developed to impart a specific motion to an object deployed in space. This rocket motor effectively eliminated the need for a cold-gas thruster system or mechanical spin-up system. A low-energy igniter, an XMC4397, employing a semiconductor bridge was used to ignite the rocket motor. The rocket motor was ground-tested in a vacuum tank to verify predicted space performance and successfully flown in a Sandia National Laboratories flight vehicle program.

As part of the Advanced Technologies for International and Intermodal Ports of Entry (ATIPE) Project, a diverse group of stakeholders was engaged to help identify problems experienced at inland international border crossings, particularly those at the US-Mexican border. The fundamental issue at international ports of entry is reducing transit time through the required documentation and inspection processes. Examples of other issues or problems, typically manifested as time delays at border crossings, repeatedly mentioned by stakeholders include: (1) lack of document standardization; (2) failure to standardize inspection processes; (3) inadequate information and communications systems; (4) manual fee and tariff collection; (5) inconsistency of processes and procedures; and (6) suboptimal cooperation among governmental agencies. Most of these issues can be addressed to some extent by the development of advanced technologies with the objective of allowing ports of entry to become more efficient while being more effective. Three categories of technologies were unambiguously of high priority to port of entry stakeholders: (1) automated documentation; (2) systems integration; and (3) vehicle and cargo tracking. Together, these technologies represent many of the technical components necessary for pre-clearance of freight approaching international ports of entry. Integration of vehicle and cargo tracking systems with port of entry information and communications systems, as well as existing industry legacy systems, should further enable border crossings to be accomplished consistently with optimal processing times.

The thermal stability of fluorinated SiO2 films (SiOF) was found to be dependent on F content and the type of substrate upon which the film was deposited. SiOF films with a range of F concentrations were deposited using an electron cyclotron resonance (ECR) plasma upon Si, Al/Si, TiN/Al/Si, and Al/SiO2/Si substrates. Following deposition, the films were deliberately hydrated and/or annealed and their stability assessed. Hydration was found to only affect the high F content films. Capacitance changes with annealing in the high F content films were found to occur beginning at 200 °C. These changes, which were independent of substrate type, likely occurred due to desorption of H2O in the films. After annealing of the high F content films up to 400 °C, a reduction in F content was found for SiOF films on some substrates. Significant reductions were found for SiOF films on Al/Si substrates, while little or no change was found for films on TiN/Al/Si, Al/SiO2/Si, or Si substrates. Local chemical analysis of those films which showed F reduction indicated that the F profile was approximately uniform throughout the layer and did not pile-up at the interface. The substrate-dependent thermal instability exhibited by these films suggests the chemical nature or qualities of the substrate may play a role in the F reduction reaction.

An acousto-optic (AO) deflector composed of PbMoO4 was exposed to 4 MeV protons while operating under Bragg angle conditions. An ion beam in air of 1 mm width was directed normal to the crystal face and laser beam. Between exposures, the approximately 13 mm × 8.5 mm AO deflector was mechanically translated in two dimensions in front of the fixed ion beam. The AO diffraction efficiency was mapped and was observed to change as a function of ion beam location and dose rate. These effects are attributed to the induced change in the temperature distribution of the crystal, which changed the sonic velocity and refractive index. Similar effects were observed when the ion beam was directed at the acoustic transducer.

Charge collection and SEU from angled ion strikes are studied using three-dimensional simulation. The physics of charge collection in unloaded diodes and transistors is explored, as is the angular dependence of upset threshold in CMOS SRAMs. The simulation results are compared to analytical models for charge collection. Modeling fundamental transport in SRAMs, the true effective LET relationship is computed and used to analyze experimental heavy-ion data. Impacts on SEU test methodology are discussed. © 1997, IEEE. All rights reserved.

A room Co-60 source was characterized using thermoluminescent dosimeters (TLDs) and pMOS RADFETs. Measurements were made over a range of dose rates between 0.8 and 100 mrad(Si)/s. Dose enhancement (DE) was measured using RADFETs with and without gold-flashed kovar lids. DE factors ranged from 1.05 to 2.35. A method was developed to predict dose enhancement as a function of position and test configuration. This method involves separation of direct and scattered gamma dose rate contributions. ©1997 IEEE.

The simultaneous formation of a filler phase and a polymer matrix via in situ sol-gel techniques provides silica-siloxane nanocomposite materials of high strength. This study concentrates on investigating the effects of temperature and relative humidity (RH) on a trimodal polymer system in an attempt to accelerate the reaction as well as evaluate subtle process-structure-property relationships. It was found that successful process acceleration is only viable for high humidity systems when using the tin(IV) catalyst dibutyltin dilaurate (DBTDL). Processes involving low humidity were found to be very temperature and time dependent. Bimodal systems were investigated and demonstrated that the presence of a short-chain component led to enhanced material strength. This part of the study also revealed a link between the particle size and population density and the optimization of material properties.

During July-November, 1995, Sandia National Laboratories, in cooperation with CE Exploration, drilled a 5,360 foot exploratory slimhole (3.85 inches diameter) in the Newberry Known Geothermal Resource Area (KGRA) near Bend, Oregon. This well was part of Sandia`s program to evaluate slimholes as a geothermal exploration tool. During and after drilling the authors performed numerous temperature logs, and at the completion of drilling attempted to perform injection tests. In addition to these measurements, the well`s data set includes: over 4,000 feet of continuous core (with detailed log); daily drilling reports from Sandia and from drilling contractor personnel; daily drilling fluid record; and comparative data from other wells drilled in the Newberry KGRA.

A high temperature spectral gamma tool has been designed and built for use in small-diameter geothermal exploration wells. Several engineering judgments are discussed regarding operating parameters, well model selection, and signal processing. An actual well log at elevated temperatures is given with spectral gamma reading showing repeatability.

Finite-difference, prestack depth migrations offers significant improvements over Kirchhoff methods in imaging near or under salt structures. We have implemented a finite-difference prestack depth migration algorithm for use on massively parallel computers which is discussed. The image quality of the finite-difference scheme has been investigated and suggested improvements are discussed.

A key to reducing the risks and costs of associated with oil and gas exploration is the fast, accurate imaging of complex geologies, such as salt domes in the Gulf of Mexico and overthrust regions in U.S. onshore regions. Pre-stack depth migration generally yields the most accurate images, and one approach to this is to solve the scalar-wave equation using finite differences. Current industry computational capabilities are insufficient for the application of finite-difference, 3-D, prestack, depth-migration algorithms. High performance computers and state-of-the-art algorithms and software are required to meet this need. As part of an ongoing ACT1 project funded by the U.S. Department of Energy, we have developed a finite-difference, 3-D prestack, depth-migration code for massively parallel computer systems. The goal of this work is to demonstrate that massively parallel computers (thousands of processors) can be used efficiently for seismic imaging, and that sufficient computing power exists (or soon will exist) to make finite-difference, prestack, depth migration practical for oil and gas exploration.

A new downhole sampling tool has been built for use in steam wells at The Geysers geothermal reservoir. The tool condenses specimens into an initially evacuated vessel that is opened down hole at the direction of an on-board computer. The tool makes a temperature log of the well as it is deployed, and the pressure and temperature of collected specimens are monitored for diagnostic purposes. Initial tests were encouraging, and the Department of Energy has funded an expanded effort that includes data gathering needed to develop a three-dimensional model of The Geysers geochemical environment. Collected data will be useful for understanding the origins of hydrogen chloride and non-condensable gases in the steam, as well as tracking the effect of injection on the composition of produced steam. Interested parties are invited to observe the work and to join the program.

We describe the metal-organic chemical vapor deposition of InAsSb/InAsP strained-layer superlattice (SLS) active regions for use in mid-infrared emitters. These SLSs were grown at 500°C, and 200 torr in a horizontal quartz reactor using trimethylindium, triethylantimony, AsH3, and PH3. By changing the layer thickness and composition we have prepared structures with low temperature (les/20 K) photoluminescence wavelengths ranging from 3.2 to 5.0 μm. Excellent performance was observed for an SLS light emitting diode (LED) and both optically pumped and electrically injected SLS lasers. An InAsSb/InAsP SLS injection laser emitted at 3.3 μm at 80 K with peak power of 100 mW.

We present a numerical method for nonisothermal, multiphase subsurface transport in heterogeneous porous media. The mathematical model considers nonisothermal two-phase (liquid/gas) flow, including capillary pressure effects, binary diffusion in the gas phase, conductive, latent, and sensible heat transport. The Galerkin finite element method is used for spatial discretization, and temporal integration is accomplished via a predictor/corrector scheme. Message-passing and domain decomposition techniques are used for implementing a scalable algorithm for distributed memory parallel computers. An illustrative application is shown to demonstrate capabilities and performance.

The second silicon revolution will be based on intelligent, integrated microsystems where multiple technologies (such as analog, digital, memory, sensor, micro-electro-mechanical, and communication devices) are integrated onto a single chip or within a multichip module. A necessary element for such systems is cost-effective, high-performance packaging. This paper examines many of the issues associated with the packaging of integrated microsystems, with an emphasis on the areas of packaging design, manufacturability, and reliability. © 1997 Published by Elsevier Science Ltd.

The Authenticated Tracking and Monitoring System (ATMS) answers the need for global monitoring of the status and location of sensitive items on a worldwide basis, 24 hours a day. The ATMS concept uses wireless sensor packs to monitor the status of the items and environmental conditions, to collect a variety of sensor event data, and to transmit the data through the INMARSAT satellite communication system, which then sends the data to appropriate ground stations for tracking and monitoring. Authentication and encryption algorithms are used throughout the system to secure the data during communication activities. A typical ATMS application would be to track and monitor the safety and security of a number of items in transit along a scheduled shipping route. The resulting tracking, timing, and status information could then be processed to ensure compliance with various agreements. Following discussions between the Australian Safeguards Office (ASO), the U.S. Department of Energy (DOE), and Sandia National Laboratories (SNL) in early 1995, the parties mutually decided to conduct and evaluate a field trial prototype ATMS to track and monitor shipments of uranium ore concentrate (UOC) from a currently operating uranium mine in Australia to a final destination in Europe. This trial is in the process of being conducted on a worldwide basis with tracking and monitoring stations located at sites in both Australia and the U.S. This paper describes the trial.

We have investigated two types of extended defects commonly found in AlN, GaN and InN films using density-functional techniques. First, basal-plane stacking faults have been studied for all three compounds. Stacking-fault energies were found to be largest in AlN and smallest in GaN consistent with density-functional results for their wurtzite/zinc-blende energy differences. In addition, the 4H and 6H structures were found to have lower energies than zinc blende for all three compounds. Second, we have investigated the electronic structure and formation energy for an edge dislocation in AlN. The full-core dislocation structure was found to have a filled electronic level approximately 0.55 eV above the valence-band edge and an empty level 1.4 eV below the conduction-band edge. An open-core structure was found to have filled and empty electronic levels closer to the middle of the energy gap. Formation energies for these two geometries suggest that the full-core structure would be expected to form in p-type material whereas both are expected in n-type material.

Amorphous carbon is an elemental form of carbon with low hydrogen content, which may be deposited in thin films by the impact of high energy carbon atoms or ions. It is structurally distinct from the more well-known elemental forms of carbon, diamond and graphite. It is distinct in physical and chemical properties from the material known as diamond-like carbon, a form which is also amorphous but which has a higher hydrogen content, typically near 40 atomic percent. Amorphous carbon also has distinctive Raman spectra, whose patterns depend, through resonance enhancement effects, not only on deposition conditions but also on the wavelength selected for Raman excitation. This paper provides an overview of the Raman spectroscopy of amorphous carbon and describes how Raman spectral patterns correlate to film deposition conditions, physical properties and molecular level structure.

High-density plasma etching has been an effective patterning technique for the group-III nitrides due to ion fluxes which are 2 to 4 orders of magnitude higher than more conventional reactive ion etch (RIE) systems. GaN etch rates exceeding 0.68 μm/min have been reported in Cl2/H2/Ar inductively coupled plasmas (ICP) at -280 V dc-bias. Under these conditions, the etch mechanism is dominated by ion bombardment energies which can induce damage and minimize etch selectivity. High selectivity etch processes are often necessary for heterostructure devices which are becoming more prominent as growth techniques improve. In this study, we will report high-density ICP etch rates and selectivities for GaN, AlN, and InN as a function of cathode power, ICP-source power, and chamber pressure. GaN:AlN selectivities >8:1 were observed in a Cl2/Ar plasma at 10 m Torr pressure, 500 W ICP-source power, and 130 W cathode rf-power, while the GaN:InN selectivity was optimized at approximately 6.5:1 at 5 m Torr, 500 W ICP-source power, and 130 W cathode rf-power.

This is a general overview of what Sandia National Laboratories` Renewable Energy Office is

Structural dynamic testing is concerned with the estimation of system properties, including frequency response functions and modal characteristics. These properties are derived from tests on the structure of interest, during which excitations and responses are measured and Fourier techniques are used to reduce the data. The inputs used in a test are frequently random, and they excite random responses in the structure of interest When these random inputs and responses are analyzed they yield estimates of system properties that are random variable and random process realizations. Of course, such estimates of system properties vary randomly from one test to another, but even when deterministic inputs are used to excite a structure, the estimated properties vary from test to test. When test excitations and responses are normally distributed, classical techniques permit us to statistically analyze inputs, responses, and some system parameters. However, when the input excitations are non-normal, the system is nonlinear, and/or the property of interest is anything but the simplest, the classical analyses break down. The bootstrap is a technique for the statistical analysis of data that are not necessarily normally distributed. It can be used to statistically analyze any measure of input excitation or response, or any system property, when data are available to make an estimate. It is designed to estimate the standard error, bias, and confidence intervals of parameter estimates. This paper shows how the bootstrap can be applied to the statistical analysis of modal parameters.

A high-frequency multibounce radar scattering code was used as a simulation platform for demonstrating an algorithm to compute the ARC of specific radar targets. To illustrate this simulation process, several targets models were used. Simulation results for a sphere model were used to determine the errors of approximation associated with the simulation; verifying the process. The severity of glint induced tracking errors was also illustrated using a model of an F-15 aircraft. It was shown, in a deterministic manner, that the ARC of a target can fall well outside its physical extent. Finally, the apparent radar centroid simulation based on a ray casting procedure is well suited for use on most massively parallel computing platforms and could lead to the development of a near real-time radar tracking simulation for applications such as endgame fuzing, survivability, and vulnerability analyses using specific radar targets and fuze algorithms.

An acousto-ultrasonic inspection technique was developed to evaluate the structural integrity of the epoxy bond interface between a metal insert and the fiber glass epoxy composite of a wind turbine blade. Data was generated manually as well as with a PC based data acquisition and display system. C-scan imaging using a portable ultrasonic scanning system provided an area mapping of the delamination or disbond due to fatigue testing and normal field operation conditions of the turbine blade. Comparison of the inspection data with a destructive visual examination of the bond interface to determine the extent of the disbond showed good agreement between the acousto-ultrasonic inspection data and the visual data.

Sandia National Laboratories is developing a technology called Laser Engineered Net Shaping{trademark} (LENS{trademark}). This process allows complex 3-dimensional solid metallic objects to be directly fabricated for a CAD solid model. Experiments performed demonstrate that complex alloys such as Inconel{trademark} 625 and ANSI stainless steel alloy 316 can be used in the LENS{trademark} process to produce solid metallic-shapes. In fact, the fabricated structures exhibit grain growth across the deposition layer boundaries. Mechanical testing data of deposited 316 stainless steel material indicates that the deposited material strength and elongation are greater than that reported for annealed 316 stainless steel. Electron microprobe analysis of the deposited Inconel{trademark} 625 material shows no compositional degradation of the 625 alloy and that 100% dense structures can be obtained using this technique. High speed imaging used to acquire process data during experimentation shows that the powder particle size range can significantly affect the stability, and subsequently, the performance of the powder deposition process. Finally, dimensional studies suggest that dimensional accuracy to {+-} 0.002 inches (in the horizontal direction) can be maintained.

Inverse protein folding concerns the identification of an amino acid sequence that folds to a given structure. Sequence design problems attempt to avoid the apparent difficulty of inverse protein folding by defining an energy that can be minimized to find protein-like sequences. The authors evaluate the practical relevance of two sequence design problems by analyzing their computation complexity. They show that the canonical method of sequence design is intractable, and describe approximation algorithms for this problem. The authors also describe an efficient algorithm that exactly solves the grand canonical method. The analysis shows how sequence design problems can fail to reduce the difficulty of the inverse protein folding problem, and highlights the need to analyze these problems to evaluate their practical relevance.

Stress in thin films plays a critical role in many technologically important areas. The role is a beneficial one in strained layer superlattices where semiconductor electrical and optical properties can be tailored with film stress. On the negative side, residual stress in thin-film interconnects in microelectronics can lead to cracking and delamination. In spite of their importance, however, surface and thin-film stresses are difficult to measure and control, especially on a local level. In recent studies, we used the Interfacial Force Microscope (IFM) in a nanoindenter mode to survey the nanomechanical properties of Au films grown on various substrates. Quantitative tabulations of the indentation modulus and the maximum shear stress at the plastic threshold showed consistent values over individual samples but a wide variation from substrate to substrate. These values were compared with film properties such as surface roughness, average grain size and interfacial adhesion and no correlation was found. However, in a subsequent analysis of the results, we found consistencies which support the integrity of the data and point to the fact that the results are sensitive to some property of the various film/substrate combinations. In recent measurements on two of the original substrate materials we found a direct correlation between the nanomechanical values and the residual stress in the films, as measured globally by a wafer warping technique. In the present paper, we review these earlier results and show recent measurements dealing with stresses externally applied to the films which supports our earlier conclusion concerning the role of stress on our measurements. In addition, we present very recent results concerning morphological effects on nanomechanical properties which add additional support to the suggestion that near-threshold indentation holds promise of being able to measure stress on a very local level.

In this work we show that annealing of silicon/silicon-dioxide/silicon structures in forming gas (N{sub 2}:H{sub 2}; 95:5) above 500{degrees}C leads to spontaneous incorporation of mobile H{sup +} ions in the buried SiO{sub 2} layer. We demonstrate that, unlike the alkali ions feared as killer contaminants in the early days, the space charge distribution of these mobile protons within the buried oxide layer can be very well controlled and easily rearranged with relatively high speed at room temperature. The hysteresis in the flat band voltage shift provides a unique vehicle to study proton kinetics in silicon dioxide thin films. It is further shown how this effect can be used as the basis for a reliable nonvolatile FET memory device that has potential to be competitive with state-of-the-art Si-based memory technologies. The power of this novel device is its simplicity; it requires few processing steps, all of which are standard in Si integrated-circuit fabrication.

Three important oxidation regimes have been identified in the temporal evolution of the wet thermal oxidation of Al{sub x}Ga{sub 1-x}As (1 {ge} x {ge} 0.90) on GaAs: (1) oxidation of Al and Ga in the Al{sub x}Ga{sub 1-x}As alloy to form an amorphous oxide layer, (2) oxidative formation and elimination of elemental As (both crystalline and amorphous) and of amorphous As{sub 2}O{sub 3}, and (3) crystallization of the oxide film. Residual As can result in up to a 100-fold increase in leakage current and a 30% increase in the dielectric constant and produce strong Fermi-level pinning and high leakage currents at the oxidized Al{sub x}Ga{sub 1-x}As/GaAs interface. The presence of thermodynamically-favored interfacial As may impose a fundamental limitation on the application of AlGaAs wet oxidation for achieving MIS devices in the GaAs material system.

Ab initio Hartree-Fock and second-order Moeller-Plesset theory calculations have been performed to investigate the stability of triply-coordinated O{sup +} centers in the Si-O-Si network of amorphous SiO{sub 2}. The calculations reveal that the H{sup +} ion binds with a bridging O center to form a very stable (D{sub e} > 6 eV) trivalent O complex. Capture of an electron by the positively charged protonated complex, however, is predicted to immediately lead to the dissociation of the O-H bond. A relatively weaker, but stable bond is also formed between the bridging O atom and a {sup +}SiH{sub 3} ion.

Fission foils are commonly used as dosimetry sensors. They play a very important role in neutron spectrum determinations. This paper provides a combination of experimental measurements and calculations to quantify the importance and synergy of several factors that affect the fission response of a dosimeter. Only when these effects are properly treated can fission dosimeters be used with sufficient fidelity.

The Waste Isolation Pilot Plant (WIPP) is a repository for transuranic wastes constructed in bedded Permian-age halite in the Delaware Basin, a sedimentary basin in southeastern New Mexico, USA. A drilling scenario has been identified during performance assessment (PA) that could lead to the release of radionuclides to the Culebra Dolomite Member of the Rustler Formation, the most transmissive water-saturated unit above the repository horizon. Were this to occur, the radionuclides would need to be largely contained within the Culebra (or neighboring strata) within the WIPP-site boundary through the period lasting for 10,000 years after repository closure for WIPP to remain in compliance with applicable regulations on allowable releases. Thus, processes affecting transport of radionuclides within the Culebra are of importance to PA.

A discrete element computer program named DMC{_}BLAST (Distinct Motion Code) has been under development since 1987 for modeling rock blasting. This program employs explicit time integration and uses spherical or cylindrical elements that are represented as circles in 2-D. DMC{_}BLAST calculations compare favorably with data from actual bench blasts. The blast modeling capabilities of DMC{_}BLAST have been expanded to include independently dipping geologic layers, top surface, bottom surface and pit floor. The pit can also now be defined using coordinates based on the toe of the bench. A method for modeling decked explosives has been developed which allows accurate treatment of the inert materials (stemming) in the explosive column and approximate treatment of different explosives in the same blasthole. A DMC{_}BLAST user can specify decking through a specific geologic layer with either inert material or a different explosive. Another new feature of DMC{_}BLAST is specification of an uplift angle which is the angle between the normal to the blasthole and a vector defining the direction of explosive loading on particles adjacent to the blasthole. A buffer (choke) blast capability has been added for situations where previously blasted material is adjacent to the free face of the bench preventing any significant lateral motion during the blast.

Vertical-axis wind turbine technology is not well understood, even though the earliest wind machines rotated about a vertical axis. The operating environment of a vertical-axis wind turbine is quite complex, but detailed analysis capabilities have been developed and verified over the last 30 years. Although vertical-axis technology has not been widely commercialized, it exhibits both advantages and disadvantages compared to horizontal-axis technology, and in some applications, it appears to offer significant advantages.

This study presents a combined analytical and experimental effort to characterize and improve the ride quality of the Department of Energy tractor/trailer combination. The focus is to augment the experimental test results with the use of a high quality computer model. The discussion includes an overview of the finite element model of the vehicle and experimental modal test results. System identification techniques are employed to update the mathematical model. The validated model is then used to illustrate the benefits of incorporating two major design changes, namely the switch from a separate cab/sleeper configuration to an integrated cab, and the use of a cab suspension system.

Crime prevention is on the minds of most people today. The concern for public safety and the theft of valuable assets are being discussed at all levels of government and throughout the public sector. There is a growing demand for security systems that can adequately safeguard people and valuable assets against the sophistication of those criminals or adversaries who pose a threat. The crime in this country has been estimated at $70 billion in direct costs and up to $300 billion in indirect costs. Health insurance fraud alone is estimated to cost American businesses $100 billion. Theft, warranty fraud, and counterfeiting of computer hardware totaled $3 billion in 1994. A threat analysis is a prerequisite to any security system design to assess the vulnerabilities with respect to the anticipated threat. Having established a comprehensive definition of the threat, crime prevention, detection, and threat assessment technologies can be used to address these criminal activities. This talk will outline the process used to design a security system regardless of the level of security. This methodology has been applied to many applications including: government high security facilities; residential and commercial intrusion detection and assessment; anti-counterfeiting/fraud detection technologies (counterfeit currency, cellular phone billing, credit card fraud, health care fraud, passport, green cards, and questionable documents); industrial espionage detection and prevention (intellectual property, computer chips, etc.); and security barrier technology (creation of delay such as gates, vaults, etc.).

There are many technologies emerging from this decade that can be used to help the law enforcement community protect the public as well as public and private facilities against ever increasing threats to this country and its resources. These technologies include sensors, closed circuit television (CCTV), access control, contraband detection, communications, control and display, barriers, and various component and system modeling techniques. This paper will introduce some of the various technologies that have been examined for the Department of Energy that could be applied to various law enforcement applications. They include: (1) scannerless laser radar; (2) next generation security systems; (3) response force video information helmet system; (4) access delay technologies; (5) rapidly deployable intrusion detection systems; and (6) cost risk benefit analysis.

It is common practice in structural dynamics to develop mathematical models for system behavior, and the authors are now capable of developing stochastic models, i.e., models whose parameters are random variables. Such models have random characteristics that are meant to simulate the randomness in characteristics of experimentally observed systems. This paper suggests a formal statistical procedure for the validation of mathematical models of stochastic systems when data taken during operation of the stochastic system are available. The statistical characteristics of the experimental system are obtained using the bootstrap, a technique for the statistical analysis of non-Gaussian data. The authors propose a procedure to determine whether or not a mathematical model is an acceptable model of a stochastic system with regard to user-specified measures of system behavior. A numerical example is presented to demonstrate the application of the technique.

This paper presents several applications of virtual reality relevant to the areas of nuclear safeguards and non-proliferation. Each of these applications was developed to the prototype stage at Sandia National Laboratories` Virtual Reality and Intelligent Simulation laboratory. These applications include the use of virtual reality for facility visualization, training of inspection personnel, and security and monitoring of nuclear facilities.

Mathematical models of physical systems are used, among other purposes, to improve our understanding of the behavior of physical systems, predict physical system response, and control the responses of systems. Phenomenological models are frequently used to simulate system behavior, but an alternative is available - the artificial neural network (ANN). The ANN is an inductive, or data-based model for the simulation of input/output mappings. The ANN can be used in numerous frameworks to simulate physical system behavior. ANNs require training data to learn patterns of input/output behavior, and once trained, they can be used to simulate system behavior within the space where they were trained.They do this by interpolating specified inputs among the training inputs to yield outputs that are interpolations of =Ming outputs. The reason for using ANNs for the simulation of system response is that they provide accurate approximations of system behavior and are typically much more efficient than phenomenological models. This efficiency is very important in situations where multiple response computations are required, as in, for example, Monte Carlo analysis of probabilistic system response. This paper describes two frameworks in which we have used ANNs to good advantage in the approximate simulation of the behavior of physical system response. These frameworks are the non-recurrent and recurrent frameworks. It is assumed in these applications that physical experiments have been performed to obtain data characterizing the behavior of a system, or that an accurate finite element model has been run to establish system response. The paper provides brief discussions on the operation of ANNs, the operation of two different types of mechanical systems, and approaches to the solution of some special problems that occur in connection with ANN simulation of physical system response. Numerical examples are presented to demonstrate system simulation with ANNs.

This paper summarizes a virtual reality universe application in which a user can travel between four virtual worlds through the use of haptic buttons. Each of the worlds demonstrates different aspects of haptic rendering which together create a wide base for force feedback effects. Specifics of the rendering algorithms will be discussed along with possible uses and modifications for other real-life applications.

This paper summarizes the U.S. Department of Energy R&D program in crystalline-silicon photovoltaic technology, which is jointly managed by Sandia National Laboratories and National Renewable Energy Laboratory. This program features a balance of basic an d applied R&D, and of university, industry, and national laboratory R&D. The goal of the crystalline-silicon R&D program is to accelerate the commercial growth of crystalline-silicon photovoltaic technology, and four strategic objectives were identified to address this program goal. Technical progress towards meeting these objectives is reviewed.

The automatic evaluation of graphical user interfaces can help reduce development costs in the creation of new designs or modification of existing designs. Several standards for the X Window System have been proposed or implemented that could greatly reduce the time spent evaluating GUIs. We implemented a User Interface Testbed (UseIT) based on the proposed Remote Access Protocol (RAP) standard. UseIT was created to automatically record an end user`s interaction with a Motif GUI application without modification or re-linking of existing code. The recorded interaction could then be replayed or displayed visually for interpretation by a human factors specialist. The end goal was to recreate the GUI and automatically recommend design changes based upon the interactions.

This paper provides new test methods and analytical procedures for characterizing the electrical performance of photovoltaic modules and arrays. The methods use outdoor measurements to provide performance parameters both at standard reporting conditions and for all operating conditions encountered by typical photovoltaic systems. Improvements over previously used test methods are identified, and examples of the successful application of the methodology are provided for crystalline- and amorphous-silicon modules and arrays. This work provides an improved understanding of module and array performance characteristics, and perhaps most importantly, a straight- forward yet rigorous model for predicting array performance at all operating conditions. For the first time, the influences of solar irradiance, operating temperature, solar spectrum, solar angle-of- incidence, and temperature coefficients are all addressed in a practical way that will benefit both designers and users of photovoltaics.

There has been little systematic study of the cause of dead (inactive) layers in II-VI phosphors used in thin film electroluminescent devices. This paper discusses preparation and characterization of rf sputter deposited Eu-doped Sr sulfide (SrS:Eu) thin films for use in a study to determine the cause of the dead layer. (The dead layer`s behavior is likely influenced by thin film composition, crystallinity, and microstructure.) We have deposited SrS:Eu thin films in a repeatable, consistent manner and have characterized properties such as composition, crystallinity, and microstructure as well as photoluminescent (PL) and electroluminescent behavior. The composition was determined using Rutherford backscattering spectrometry and electron microprobe analysis. XRD was used to assess crystalline orientation and grain size, SEM to image thin film microstructure. Measuring the PL decay after subnanosecond laser excitation in the lowest absorption band of the dopant allowed direct measurement of the dopant luminescence efficiency.

To ensure high levels of deterrent capability in the 21st century, new stockpile stewardship principles are being embraced at Sandia National Laboratories. The Department of Energy Accelerated Strategic Computing Initiative (ASCI) program is providing the computational capacity and capability as well as funding the system and simulation software infrastructure necessary to provide accurate, precise and predictive modeling of important components and devices. An important class of components require modeling of piezoelectric and ferroceramic materials. The capability to run highly resolved simulations of these types of components on the ASCI parallel computers is being developed at Sandia in the ElectroMechanical Modeling in Alegra (EMMA) code. This a simulation capability being developed at Sandia National Laboratories for high-fidelity modeling of electromechanical devices. these devices can produce electrical current arising from material changes due to shock impact or explosive detonation.

This paper discusses Sandia National Laboratories` development of new technologies for use in the Vietnam War - specifically the seismic sensors deployed to detect troop and vehicle movement - first along the Ho Chi Minh Trail and later in perimeter defense for American military encampments in South Vietnam. Although the sensor story is a small one, it is interesting because it dovetails nicely with our understanding of the war in Vietnam and its frustrations; of the creation of new technologies for war and American enthusiasm for that technology; and of a technological military and the organizational research and a m am development structure created to support it. Within the defense establishment, the sensors were proposed within the context of a larger concept - that of a barrier to prevent the infiltration of troops and supplies from North Vietnam to the South. All of the discussion of the best way to fight in Vietnam is couched in the perception that this was a different kind of war than America was used to fighting. The emphasis was on countering the problems posed by guerrilla/revolutionary warfare and eventually by the apparent constraints of being involved in a military action, not an outright war. The American response was to find the right technology to do the job - to control the war by applying a technological tincture to its wounds and to make the war familiar and fightable on American terms. And, when doubts were raised about the effectiveness of applying existing technologies (namely, the bombing of North Vietnam and Laos), the doubters turned to new technologies. The sensors that were developed for use in Vietnam were a direct product of this sort of thinking - on the part of the engineers at Sandia who created the sensors, the civilian scientific advisors who recommended them, and, ultimately, the soldiers in the field who had to use them.

For the past few years, the Minnesota Department of Corrections, assisted by Sandia National Laboratories, has developed a set of standards for perimeter security at medium, close, and maximum custody correctional facilities in the state. During this process, the threat to perimeter security was examined and concepts about correctional perimeter security were developed. This presentation and paper will review the outcomes of this effort, some of the lessons learned, and the concepts developed during this process and in the course of working with architects, engineers and construction firms as the state upgraded perimeter security at some facilities and planned new construction at other facilities.

This paper documents the history of photovoltaic use within the Department of Defense leading up to the installation of 2.1 MW of photovoltaics underway today. This history describes the evolution of the Department of Defense`s Tri-Service Photovoltaic Review Committee and the committee`s strategic plan to realize photovoltaic`s fall potential through outreach, conditioning of the federal procurement system, and specific project development. The Photovoltaic Review Committee estimates photovoltaic`s potential at nearly 4,000 MW, of which about 700 MW are considered to be cost-effective at today`s prices. The paper describes photovoltaic`s potential within the Department of Defense, the status and features of the 2.1 MW worth of photovoltaic systems under installation, and how these systems are selected and implemented. The paper also documents support provided to the Department of Defense by the Department of Energy dating back to the late 70s.

High heat flux testing for the United States fusion power program is the primary mission of the Plasma Materials Test Facility (PMTF) located at Sandia National Laboratories in Albuquerque, New Mexico. This facility, an official Department of Energy User Facility, has been in operation for over 15 years and has provided much of the high heat flux data used in the design and evaluation of plasma facing components for many of the world`s magnetic fusion tokamak experiments. In addition to domestic tokamaks such as Tokamak Fusion Test Reactor (TFTR) at Princeton, the DIII-D tokamak pt General Atomics, and Alcator C-Mod at MIT, components for international experiments like TEXTOR, Tore-Supra, and JET also have been tested at the PMTF. High heat flux testing spans a wide spectrum including thermal shock tests on passively cooled materials, thermal response and thermal fatigue tests on actively cooled components, critical heat flux burnout tests, braze reliability tests, and safety related tests. The program`s main focus now is on testing of beryllium and tungsten armor tiles bonded to divertor, limiter, and first wall components for the International Thermonuclear Experimental Reactor (ITER). The ITER project is a collaboration among the US, EU, RF, and Japanese fusion programs. This article provides a brief overview of the high heat flux testing capabilities at the PMTF, and describes some recent test results.