Publications

Cooperative monitoring holds the promise of utilizing many technologies from conflicts of the past to implement agreements of peace in the future. Important approaches to accomplish this are to develop the framework for assessing monitoring opportunities and to provide education and training on the technologies and experience available for sharing with others. The Cooperative Monitoring Center (CMC) at Sandia National Laboratories is working closely with agencies throughout the federal government, academics at home and abroad, and regional organizations to provide the technical tools needed to assess, design, analyze, and implement these cooperative agreements. In doing so, the goals of building regional confidence and increasing trust and communication can be furthered.

Several techniques to predict pad failure during tungsten CMP were investigated for a specific consumable set. These techniques include blanket polish rate measurements and metrics derived from two endpoint detection schemes. Blanket polish rate decreased significantly near pad failure. Metrics from the thermal endpoint technique included change in peak temperature, change in the time to reach peak temperature, and the change in the slope of the temperature trace just prior to peak temperature all as a function of pad life. Average carrier motor current before endpoint was also investigated. Changes in these metrics were observed however these changes, excluding time to peak process temperature, were either not consistent between pads or too noisy to be reliable predictors of pad failure.

This paper details the analysis of vibration monitoring for end-point control in oxide CMP processes. Two piezoelectric accelerometers were integrated onto the backside of a stainless steel polishing head of an IPEC 472 polisher. One sensor was placed perpendicular to the carrier plate (vertical) and the other parallel to the plate (horizontal). Wafers patterned with metal and coated with oxide material were polished at different speeds and pressures. Our results show that it is possible to sense a change in the vibration signal over time during planarization of oxide material on patterned wafers. The horizontal accelerometer showed more sensitivity to change in vibration amplitude compared to the vertical accelerometer for a given polish condition. At low carrier and platen rotation rates, the change in vibration signal over time at fixed frequencies decreased approximately ½ - 1 order of magnitude (over the 2 to 10 psi polish pressure ranges). At high rotation speeds, the vibration signal remained essentially constant indicating that other factors dominated the vibration signaL These results show that while it is possible to sense changes in acceleration during polishing, more robust hardware and signal processing algorithms are required to ensure its use over a wide range of process conditions.

Abstract not provided.

Casing deformation in wells is a common problem in many geothermal fields. Casing remediation is necessary to keep wells in production and occasionally, to even enter the well for an approved plug and abandonment procedure. The costly alternative to casing remediation is to incur the expense of drilling a new well to maintain production or drilling a well to intersect a badly damaged well below the deformation for abandonment purposes. The U.S. Department of Energy and the Geothermal Drilling Organization sponsor research and development work at Sandia National Laboratories in an effort to reduce these remediation expenditures. Sandia, in cooperation with Halliburton Energy Services, has developed a low cost, commercially available, bridge-plug-type packer for use in geothermal well environments. This report documents the development and testing of this tool for use in casing remediation work.

Silicon micromachine designs include engines that consist of orthog- onally oriented linear comb drive actuators mechanically connected to a rotating gear. These gears are as small as 50 {micro}m in diameter and can be driven at rotation rates exceeding 300,000 rpm. Generally, these en- gines will run with non-uniform rotation rates if the drive signals are not properly designed and maintained over a range of system parameters. We present a method for producing constant rotation rates in a micro-engine driven by an orthogonal linkage system. We show that provided the val- ues of certain masses, springs, damping factors, and lever arms are in the right proportions, the system behaves as though it were symmetrical. We will refer to systems built in this way as being quasi-symmetrical. We show that if a system is built quasi-symmetrically , then it is possible to achieve constant rotation rates even if one does not know the form of the friction function, or the value of the friction. We analyze this case in some detail.

In this paper we present an approach that facilitates the validation of high consequence system requirements. This approach consists of automatically generating a graphical representation from an informal document. Our choice of a graphical notation is statecharts. We proceed in two steps: we first extract a hierarchical decomposition tree from a textual description, then we draw a graph that models the statechart in a hierarchical fashion. The resulting drawing is an effective requirements assessment tool that allows the end user to easily pinpoint inconsistencies and incompleteness.

We investigate the apparent charge transfer between adatoms in the GeXPb[l.XjGe(lll) interface both experimentally and theoretically. Scanning tunneling microscopy and surface core level measurements suggest significant charge transfer from the Ge adatoms to the Pb adatoms. However, first-principles calculations unambiguously find that the total electronic displacement is negligibly small, and that the results of published experiments can be explained as a result of bond rearrangement.

Friction force microscopy measurements of a polydiacetylene monolayer film reveal a 300% friction anisotropy that is correlated with the film structure. The film consists of a monolayer of the red form of N-(2-ethanol)- 10,12 pentacosadiynamide, prepared on a Langmuir trough and deposited on a mica substrate. As confirmed by atomic force microscopy and fluorescence microscopy, the monolayer consists of domains of linearly oriented conjugated backbones with pendant hydrocarbon side chains above and below the backbones. Maximum friction occurs when the sliding direction is perpendicular to the backbone. We propose that the backbones impose anisotropic packing of the hydrocarbon side chains which leads to the observed friction anisotropy. Friction anisotropy is therefore a sensitive, optically-independent indicator of polymer backbone direction and monolayer structural properties.

Abstract not provided.

We have synthesized the Z and E isomers of 1,4-bis(triethoxysilyl)-2- butene and polymerized them under acid and base catalyzed sol-gel conditions. As expected the E system formed crosslinked, insoluble gels. The Z isomer, by nature of its geometry, formed high molecular weight, soluble polymeric products under acidic conditions. We were able to prepare and isolate both the cyclic disilsesquioxane monomer, and its dimer. Comparison of their spectral characterization with that of the soluble polymers suggests that the cyclics are present within the polymers. lle synthesis of a dimer likely present at some early stage of the polymerization suggests that we may be able to control the reaction and form rigid polymers with controllable tacticity. In addition, most of the gels were found to be non-porous indicating that the gels were, in fact, more compliant than ethenylene-bridged polysilsesquioxanes leading to collapse of pores during drying.

The detection of mines, both during and after hostilities, is a growing international problem. It limits military operations during wartime and unrecovered mines create tragic consequences for civilians. From a purely humanitarian standpoint an estimated 100 million or more unrecovered mines are located in over 60 countries worldwide. This paper presents an overview of some of the technologies currently being investigated by Sandia National Laboratories for the detection and monitoring of minefields in land and water environments. The three technical areas described in this paper are: 1) the development of new mathematical techniques for combining or fusing the data from multiple sources for enhanced decision-making; 2) an environmental fate and transport (EF&T) analysis approach that is central to improving trace chemical sensing technique; and 3) the investigation of an underwater range imaging device to aid in locating and characterizing mines and other obstacles in coastal waters.

In the scanning electron microscope (SEM), using electron backscattered diffraction (EBSD), it is possible to measure the spacing of the layers in the reciprocal lattice. These values are of great use in confirming the identification of phases. The technique derives the layer spacing from the HOLZ rings which appear in patterns from many materials. The method adapts results from convergent-beam electron diffraction (CBED) in the transmission electron microscope (TEM). For many materials the measured layer spacing compares well with the calculated layer spacing. A noted exception is for higher atomic number materials. In these cases an extrapolation procedure is described that requires layer spacing measurements at a range of accelerating voltages. This procedure is shown to improves the accuracy of the technique significantly. The application of layer spacing measurements in EBSD is shown to be of use for the analysis of two polytypes of SiC.

Our vision of the future of information systems is one that includes engineered collectives of software agents which are situated in an environment over years and which increasingly improve the performance of the overall system of which they are a part. At a minimum, the movement of agent and multi-agent technology into National Security applications, including their use in information assurance, is apparent today. The use of deliberative, autonomous agents in high-consequence/high-security applications will require a commensurate level of protection and confidence in the predictability of system-level behavior. At Sandia National Laboratories, we have defined and are addressing a research agenda that integrates the surety (safety, security, and reliability) into agent-based systems at a deep level. Surety is addressed at multiple levels: The integrity of individual agents must be protected by addressing potential failure modes and vulnerabilities to malevolent threats. Providing for the surety of the collective requires attention to communications surety issues and mechanisms for identifying and working with trusted collaborators. At the highest level, using agent-based collectives within a large-scale distributed system requires the development of principled design methods to deliver the desired emergent performance or surety characteristics. This position paper will outline the research directions underway at Sandia, will discuss relevant work being performed elsewhere, and will report progress to date toward assurance in agent-based systems.

The solution-mediated syntheses and single crystal structures of (CH₃NH₃)₃·Zn₄0(AsO₄)₃ and (CH₃NH₃)₃·Zn₄O(P0₄)₃ are reported. These compounds are built up from vertex-sharing three-dimensional Zn0₄ + AsO₄/P0₄ tetrahedral frameworks encapsulating methylammonium cations in three-dimensional channel systems. These phases are closely related to the zeolite- like M₃Zn₄O(XO₄)₃·nH₂O family of phases. Crystal data for (CH₃NH₃)₃·Zn₄0(AsO₄)₃, M, = 790.47, monoclinic, space group P2₁ (No. 4), a = 7.814 (3)Å, b = 15.498 (6)Å, c = 7.815 (3) Å, {beta} = 92.91 (2)0, V = 945.1 (9) ų, Z = 2, R(F) = 3.01%, R_W(F) = 3.98% (2301 reflections, 236 parameters). Crystal data for (CH₃NH₃)₃·Zn₄0(P0₄)₃: M, = 658.63, monoclinic, space group P2₁ (No. 4), a = 7.6569 (5) Å, b = 15.241 (1)Å, c= 7.6589 (5) Å, {beta} = 92.740 (1)0, V= 892.7 (5) ų, Z = 2, R(F)= 8.07%, R_W(F)= 9.60% (2694 reflections, 106 parameters).

Zeolite W has been synthesized using organometallic silicon and aluminum precursors in two hydrothermal systems: organocation containing and organocation-free. The reaction using the organocation yielded a fully crystalline, relatively uniform crystal size product, with no organic molecules occluded in the pores. In contrast, the product obtained from an identical reaction, except for the absence of the organocation, contained amorphous as well as crystalline material and the crystalline phase showed a large diversity of both crystal size and morphology. The use of organometallic precursors, either with or without an organocation, allows for the crystallization of the MER framework at much lower 0H/Si02 and (K+ Na - Al)/Si ratios than is typical of inorganic systems. The reaction products were characterized by XRD, SEM, EDS, and thermal analyses.

The solution-mediated syntheses and single crystal structures of (N₂C₆H₁₄)·Zn(HPO₄)₂·H₂O (I), H₃N(CH₂)₃NH₃·Zn₂(HPO₄)₃ (II), and (N₂C₆H₁₄)·Zn₃(HPO₄)₄ (III) are described. These phases contain vertex-sharing Zn0₄ and HP0₄ tetrahedra, accompanied by doubly- protonated organic cations. Despite their formal chemical relationship, as members of the series of t·Zn_n(HP0₄)_n+1 (t= template, n = 1-3), these phases adopt fimdamentally different crystal structures, as one-dimensional, two-dimensional, and three-dimensional Zn0₄/HP0₄ networks, for I, II, and III respectively. Similarities and differences to some other zinc phosphates are briefly discussed. Crystal data: (N₂C₆H₁₄)·Zn(HP0₄)₂·H₂0, M_r = 389.54, monoclinic, space group P2₁/n (No. 14), a = 9.864 (4) Å, b = 8.679 (4) Å, c = 15.780 (3) Å, β = 106.86 (2)°, V= 1294.2 (8) ų, Z = 4, R(F) = 4.58%, R_W(F) = 5.28% [1055 reflections with I >3σ(I)]. H₃N(CH₂)₃NH₃·Zn₂(HP0₄)₃, M_r = 494.84, monoclinic, space group P2₁/c (No. 14), a= 8.593 (2)Å, b= 9.602 (2)Å, c= 17.001 (3)Å, β= 93.571 (8)°, V = 1400.0 (5) ų, Z = 4, R(F) = 4.09%, R_W(F) = 4.81% [2794 reflections with I > 3σ (I)]. (N₂C₆H₁₄)·Zn₃(HP0₄)₄, M_r= 694.25, monoclinic, space group P2₁/n (No. 14), a = 9.535 (2) Å, b = 23.246 (4)Å, c= 9.587 (2)Å, β= 117.74 (2)°, V= 1880.8 (8) ų, Z = 4, R(F) = 3.23%, R_W(F) = 3.89% [4255 reflections with 1> 3σ(I)].

Due to the vast diversity of chemical media in which metal separations are executed, a wide range of ion separation materials are employed. This results in an ongoing effort to discover new phases with novel ion exchange properties. We present here the synthesis of a novel class of thermally and chemically stable microporous, niobate-based materials. Ion exchange studies show these new phases are highly selective for Sr²⁺ and other bivalent metals.

Silica nanoparticles exhibiting hexagonal, cubic, and vesicular mesostructures have been prepared using aerosol assisted, self-assembled process. This process begins with homogennous aerosol droplets containing silica source, water, ethanol, and surfactant, in which surfactant concentration is far below the critical micelle concentration (cmc). Solvent evaporation enriches silica and surfactant inducing interfacial self-assembly confined to a spherical aerosol droplet and results in formation of completely solid, ordered spherical particles with stable hexagonal, cubic, or vesicular mesostructures.

Understanding of single and multi-phase flow and transport in fractures can be greatly enhanced through experimentation in transparent systems (analogs or replicas) where light transmission techniques yield quantitative measurements of aperture, solute concentration, and phase saturation fields. Here we quanti@ aperture field measurement error and demonstrate the influence of this error on the results of flow and transport simulations (hypothesized experimental results) through saturated and partially saturated fractures. find that precision and accuracy can be balanced to greatly improve the technique and We present a measurement protocol to obtain a minimum error field. Simulation results show an increased sensitivity to error as we move from flow to transport and from saturated to partially saturated conditions. Significant sensitivity under partially saturated conditions results in differences in channeling and multiple-peaked breakthrough curves. These results emphasize the critical importance of defining and minimizing error for studies of flow and transpoti in single fractures.

An investigation of the synthesis of novel dodecaarylporphyrins using the Suzuki coupling reaction of arylboronic acids with octabromotetraarylporphyrins is reported. Studies of the dynamic properties of these new porphyrins using variable temperature (VT) ¹H NMR spectroscopy and molecular mechanics provide interesting insights into their dynamic properties, including the first determination of {beta} aryl rotation in a porphyrin system.

The time evolution of the amplitude of periodic nanoscale ripple patterns formed on Ar+ sputtered Si(OOl ) surfaces was examined using a recently developed in situ spectroscopic technique. At sufficiently long times, we find that the amplitude does not continue to grow exponentially as predicted by the standard Bradley-Harper sputter rippling model. In accounting for this discrepancy, we rule out effects related to the concentration of mobile species, high surface curvature, surface energy anisotropy, and ion-surface interactions. We observe that for all wavelengths the amplitude ceases to grow when the width of the topmost terrace of the ripples is reduced to approximately 25 nm. This observation suggests that a short circuit relaxation mechanism limits amplitude . growth. A strategy for influencing the ultimate ripple amplitude is discussed.

Optimal selection of array sensors for a chemical sensing application is a nontrivial task. It is commonly believed that "more is better" when choosing the number of sensors required to achieve good chemical selectivity. However, cost and system complexity issues point towards the choice of small arrays. A quantitative array optimization is carried out to explore the selectivity of arrays of partially-selective chemical sensors as a function of array size. It is shown that modest numbers (dozens) of target analytes are completely distinguished with a range of arrays sizes. However, the array selectivity and the robustness against sensor sensitivity variability are significantly degraded if the array size is increased above a certain number of sensors, so that relatively small arrays provide the best performance. The results also suggest that data analyses for very large arrays of partially-selective sensors will be optimized by separately anal yzing small sensor subsets.

Controlled impact experiments have been performed to determine the spall strength of four different concrete compositions. The four concrete compositions are identified as, `SAC-5, CSPC', ("3/4") large, and ("3/8") small, Aggregate. They differ primarily in aggregate size but with average densities varying by less than five percent. Wave profiles from sixteen experiments, with shock amplitudes of 0.07 to 0.55 GPa, concentrate primarily within the elastic regime. Free-surface particle velocity measurements indicate consistent pullback signals in the release profiles, denoting average span strength of approximately 40 MPa. It is the purpose of this paper to present spall measurements under uniaxial strain loading. Notwithstanding considerable wave structure that is a unique characteristic to the heterogeneous nature of the scaled concrete, the spall amplitudes appear reproducible and consistent over the pressure range reported in this study.

This paper summarizes the current status of the treatment of human reliability in fire risk analyses for nuclear power plants and identifies areas that need to be addressed. A new approach is suggested to improve the modeling.

Many hazardous material handling needs exist in remote unstructured environments. Currently these operations are accomplished using personnel in direct contact with the hazards. A safe and cost effective alternative to this approach is the use of intelligent robotic systems for safe handling, packaging, transport, and even excavation of hazardous materials. The Intelligent Systems and Robotics Center of Sandia National Laboratories has developed and deployed robotic technologies for use in hazardous environments, three of which have been deployed in DOE production facilities for handling of special nuclear materials. Other systems are currently under development for packaging special nuclear materials. This paper presents an overview of the research activities, including five delivered systems, at %ndia National Laboratories on the use of robotics in hazardous environments.

Thermal instabilities were identified in SONY-type lithium-ion cells and correlated with interactions of cell constituents and reaction products. Three temperature regions of interaction were identified and associated with the state of charge (degree of Li intercalation) of the cell. Anodes were shown to undergo exothermic reactions as low as 100°C involving the solid electrolyte interface (SEI) layer and the LiPF₆ salt in the electrolyte (EC: PC: DEC/LiPF₆). These reactions could account for the thermal runaway observed in these cells beginning at 100°C. Exothermic reactions were also observed in the 200°C-300°C region between the intercalated lithium anodes, the LiPF₆ salt and the PVDF. These reactions were followed by a high- temperature reaction region, 300°C-400°C, also involving the PVDF binder and the intercalated lithium anodes. The solvent was not directly involved in these reactions but served as a moderator and transport medhun. Cathode exotherrnic reactions with the PVDF binder were observed above 200oC and increased with the state of charge (decreasing Li content). This offers an explanation for the observed lower thermal runaway temperatures for charged cells.

This paper reports progress on implementing a new capability of adaptive mesh refinement into the Eulerian multimaterial shock- physics code CTH. The adaptivity is block-based with refinement and unrefinement occurring in an isotropic 2:1 manner. The code is designed to run on serial, multiprocessor and massive parallel platforms. An approximate factor of three in memory and performance improvements over comparable resolution non-adaptive calculations has-been demonstrated for a number of problems.

The nucleation of GaN thin films on GaAs is investigated for growth at 620 "C. An rf plasma cell is used to generate chemically active nitrogen from N₂. An arsenic flux is used in the first eight monolayer of nitride growth to enhance nucleation of the cubic phase. Subsequent growth does not require an As flux to preserve the cubic phase. The nucleation of smooth interfaces and GaN films with low stacking fault densities is dependent upon relative concentrations of active nitrogen species in the plasma and on the nitrogen to gallium flux ratio.

A management system approach for evaluating environment, safety, health, and quality is in use at Sandia National Laboratories (SNL). Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000. As a multi-program national laboratory, SNL has many diverse operations including research, engineering development and applications, production, and central services supporting all activities and operations. Basic research examples include fusion power generation, nuclear reactor experiments, and investigation of combustion processes. Engineering development examples are design, testing, and prototype developments of micro-mechanical systems for safe'~arding computer systems, air bags for automobiles, satellite systems, design of transportation systems for nuclear materials, and systems for use in medical applications such as diagnostics and surgery. Production operations include manufacture of instrumented detection devices, radioisotopes, and replacement parts for previously produced engineered systems. Support services include facilities engineering, construction, and site management, site security, packaging and transportation of hazardous materials wastes, ES&H functional programs to establish requirements and guidance to comply with federal, state, local, and contractual requirements and work safety. In this diverse environment, unlike more traditional single function business units, an integrated consistent management system is not typical. Instead, each type of diverse activity has its own management system designed and distributed around the operations, personnel, customers, and facilities (e.g., hazards involved, security, regulatory requirements, and locations). Laboratory managers are not likely to have experience in the more traditional hierarchical or command and control structures and thus do not share oversight expectations found in centralized management systems. The resulting corporate management system gives the appearance of an assembly of multiple, nearly independent operating units. The executive management system maintains these separate units, encouraging autonomy and creativity by establishing a minimum of requirements and procedures. In any organization, senior management has a responsibility to ensure that all operating units are meeting requirements. Part of this responsibility is fulfilled by conducting oversight or assurance activities, to determine the effectiveness of established systems in meeting requirements and performance expectations. Internal independent assessment is one of these assurance activities. Independent appraisals are combined with external audits and appraisals, self-assessments, peer reviews, project reviews, and other internal and external audits (e.g., financial, contractual) for a more complete assurance view. At SNL, internal independent appraisals are performed by the Audit Center, which reports directly to the Executive Vice President. ES&H independent appraisals are the responsibility of the ES&H and Quality Assessments Department, with a staff complement of eight. With our organization's charter to perform internal, independent appraisals, we set out to develop an approach and associated tools, which would be useful in the overall SNL environment and within our resource limitations.

Solid Polymer Electrolytes (SPE) are widely used in batteries and fuel cells because of the high ionic conductivity that can be achieved at room temperature. The ions are usually Li or protons, although other ions can be shown to conduct in these polymer films. There has been very little work on using these films as chemical sensors. We have found that thin films of polymers like polyethyleneoxide (PEO) are very sensitive to low concentrations of volatile organic compounds (VOCS) like common solvents. We will present impedance spectroscopy of PEO films in the frequency range 0.01 Hz to 1 MHz for different concentrations of VOCS. We find that the measurement frequency is important for distinguishing ionic conductivity from the double layer capacitance and parasitic capacitances.

A procedure has been developed to represent the loading on a penetrator and its motion during oblique penetration into geologic media. The penetrator is modeled with the explicit dynamics, finite element computer program PRONTO 3D and the coupled pressure on the penetrator is given in a new loading option based on a separate cavity expansion (CE) solution that accounts for the pressure-reduction from a nearby target free surface. The free-surface influ- ence distance is selected in a predictive manner by considering the pressure to expand a spherical cavity in a finite radius sphere of the target material. The CE/PRONTO 3D procedure allows a detailed description of the penetrator for predicting shock environments or structural failure dur- ing the entire penetration event and is sufficiently rapid to be used in design optimization. It has been evaluated by comparing its results with data from two field tests of a full-scale penetrator into frozen soil at an impact angles of 49.6 and 52.5 degrees from the horizontal. The measured penetrator rotations were 24 and 22 degrees, respectively. In the simulation, the rotation was21 degrees and predominately resulted from the pressure reduction of the free surface. Good agree- ment was also found for the penetration depth and axial and lateral acceleration at two locations in the penetrator.

Chemical Equilibrium calculations are presented that are relevant to the purification of molten silicon by gas-blowing. The equilibrium distributions of silicon, boron, phosphorus carbon and iron among the solid, liquid and gas phases are reported for a variety of added chemicals, temperatures and total pressures. The identities of the dominant chemical species for each element in each phase are also provided for these conditions. The added gases examined are O(2), air, water, wet air, HCl, Cl(2), Cl(2)/O(2), SiCl(4), NH(3), NH(4)OH, and NH(4)Cl. These calculations suggest possible purification schemes, although kinetic or transport limitations may prove to be significant

Results from a Fire Test with a three-by-three stack of standard 6 m long International Standards Organization shipping containers containing combustible fuels and empty radioactive materials packages are reported and discussed. The stack is intended to simulate fire conditions that could occur during on-deck stowage on container cargo ships. The fire is initated by locating the container stack adjacent to a 9.8 x 6 m pool fire. Temperatures of both cargoes (empty and simulated radioactive materials packages) and containers are recorded and reported. Observations on the duration, intensity and spread of the fire are discussed. Based on the results, models for simulation of fire exposure of radioactive materials packages in such fires are suggested.

As a way to bootstrap the DISCOM(2) Distance Computing Program the SP2 Pilot Project was launched in March 1998. The Pilot was directed towards creating an environment to allow Sandia users to run their applications on the Accelerated Strategic Computing Initiative's (ASCI) Blue Pacific computation platform, the unclassified IBM SP2 platform at Lawrence Livermore National Laboratory (LLNL). The DISCOM(2) Pilot leverages the ASCI PSE (Problem solving Environment) efforts in networking and services to baseline the performance of the current system. Efforts in the following areas of the pilot are documented: applications, services, networking, visualization, and the system model. It details not only the running of two Sandia codes CTH and COYOTE on the Blue Pacific platform, but also the buildong of the Sandia National Laboratories (SNL) proxy environment of the RS6000 platforms to support the Sandia users.

Eigenanalysis is a critical component of structural dynamics which is essential for determinating the vibrational response of systems. This effort addresses the development of numerical algorithms associated with scalable eigensolver techniques suitable for use on massively parallel, distributed memory computers that are capable of solving large scale structural dynamics problems. An iterative Lanczos method was determined to be the best choice for the application. Scalability of the eigenproblem depends on scalability of the underlying linear solver. A multi-level solver (FETI) was selected as most promising for this component. Issues relating to heterogeneous materials, mechanisms and multipoint constraints have been examined, and the linear solver algorithm has been developed to incorporate features that result in a scalable, robust algorithm for practical structural dynamics applications. The resulting tools have been demonstrated on large problems representative of a weapon's system.

Thermal instabilities were identified in SONY-type lithium-ion cells and correlated with interactions of cell constituents and reaction products. Three temperature regions of interaction were identified and associated with the state of charge (degree of Li intercalation) of the cell. Anodes were shown to undergo exothermic reactions as low as 100 degree C involving the solid electrolyte interface (SEI) layer and the LiPF(6) salt in the electrolyte (EC-PC:DEC/IM LiPF(6)). These reactions could account for the thermal runaway observed in these cells beginning at 100 degree C. Exothermic reactions were also observed in the 200 degree C to 300 degree C region between the intercalated lithium anodes, the LiPF(6) salt, and the PVDF. These reactions were followed by a high-temperature reaction region, 300 degree C to 400 degree C, also involving the PVDF binder and the intercalated lithium anodes. The solvent was not directly involved in these reactions but served as a moderator and transport medium. Cathode exothermic reactions with the PVDF binder were observed above 200 degree C and increased with the state of charge (decreasing Li content). The stability of the PVDF binder as a function of electrochemical cycling was studied using FTIR. The infrared spectra from the extracts of both electrodes indicate that PVDF is chemically modified by exposure to the lithium cell electrolyte (as well as electrochemical cycling) in conjunction with NMP extraction. Preconditioning of PVDF to dehydrohalogenation, which may be occurring by reaction with LiPf(6), makes the PVDF susceptible to attack by a range of nucleophiles.

The steady state and transient thermal behavior of an electromigration test structure was analyzed. The test structure was a Sandia SHIELD (Self-stressing HIgh fregquency rELiability Device) electromigration test device manufactured by an outside vendor. This device has a high frequency oscillator circuit, a buffer circuit to isolate and drive the metal line to the tested (DUT), the DUT to be electromigrated itself, a metal resistance thermometry monitor, and a heater elment to temperature accelerate the electromigration effect.

A furnace has been built for the purpose of producing anisotropic porous metals through solid-gas eutectic solidification. This process allows control of continuously formed anisotropic pores in metals and was discovered at the State Metallurgical Academic' University in Dnepropetrovsk Ukraine. The process incorporates hydrogen gas within the metal as it solidifies from the molten state. Metals which do not form hydrides, including iron, nickel, aluminum, copper and others can be formed in this manner. The furnace is housed within a ~.64 meter³ (30 ft³) ASME code stamped cylindrical stainless steel vacuum/pressure vessel. The vessel is a water chilled vertical cylinder with removable covers at the top and bottom. It can be evacuated to 20 mTorr or pressurized to 5.5 MPa (800 psi). A charge of 2700 cc (167 in³) of molten metal can be melted in a crucible in the upper portion within a watercooled 30 cm (12 in.) ID induction coil. A 175 kW Inductotherm power source energizes the coil. Vertical actuation of a ceramic stopper rod allows the molten metal to be tapped into a solidification mold beneath the melting crucible. The cylindrical mold rests on a water cooled copper base inducing directional solidification from the bottom. Mixtures of hydrogen and argon gases are introduced during the process. The system is remotely controlled and located in a structure with frangible walls specially designed for possible ambient pressure excursions as a result of equipment failure. This paper includes a general description of the furnace and operating procedure and a detailed description of the control, monitoring and interlock systems.

We have developed a new multilayer a-tC material that is thick stress-free, adherent, low friction, and with hardness and stiffness near that of diamond. The new a-tC material is deposited by J pulsed-laser deposition (PLD) at room temperature, and fully stress-relieved by a short thermal anneal at 600°C. A thick multilayer is built up by repeated deposition and annealing steps. We measured 88 GPa hardness, 1100 GPa Young's modulus, and 0.1 friction coefficient (under high load). Significantly, these results are all well within the range reported for crystalline diamond. In fact, this material, if considered separate from crystalline diamond, is the 2nd hardest material known to man. Stress-free a-tC also has important advantages over thin film diamond; namely, it is smooth, processed at lower temperature, and can be grown on a much broader range of substrates. This breakthrough will enable a host of applications that we are actively pursuing in MEMs, sensors, LIGA, etc.

The Integrated Fuel-Coolant Interaction Code (IFCI) is a best-estimate computer program for analysis of phenomena related to mixing of molten nuclear reactor core material with reactor coolant (water). The stand-alone version of the code, IFCI 7.0, has been designed for analysis of small- and intermediate-scale experiments in order to gain insight into the physics (including scaling effects) of molten fuel-coolant interactions. The code's methods, models, and correlations are being assessed. This report describes the flow regime, friction factor, and heat-transfer models used in the current version of IFCI (IFCI 7.0).

Object-oriented analysis methods have been used in the computer science arena for a number of years to model the behavior of computer-based systems. This report documents how such methods can be applied to surety analysis. By embodying the causality and behavior of a system in a common object-oriented analysis model, surety analysts can make the assumptions that underlie their models explicit and thus better communicate with system designers. Furthermore, given minor extensions to traditional object-oriented analysis methods, it is possible to automatically derive a wide variety of traditional risk and reliability analysis methods from a single common object model. Automatic model extraction helps ensure consistency among analyses and enables the surety analyst to examine a system from a wider variety of viewpoints in a shorter period of time. Thus it provides a deeper understanding of a system's behaviors and surety requirements. This report documents the underlying philosophy behind the common object model representation, the methods by which such common object models can be constructed, and the rules required to interrogate the common object model for derivation of traditional risk and reliability analysis models. The methodology is demonstrated in an extensive example problem.

The integrated fuel-coolant interaction (IFCI) computer code is being developed at Sandia National Laboratories to investigate the fuel-coolant interaction (FCI) problem at large scale using a two-dimensional, three-field hydrodynamic framework and physically based models. IFCI will be capable of treating all major FCI processes in an integrated manner. This document is a description of IFCI 7.0. The user's manual describes the hydrodynamic method and physical models used in IFCI 7.0. Appendix A is an input manual provided for the creation of working decks.

We have developed a wafer fusion technology to achieve integration of semiconductor materials and heterostructures with widely disparate lattice parameters, electronic properties, and/or optical properties for novel devices not now possible on any one substrate. Using our simple fusion process which uses low temperature (400-600 C) anneals in inert N{sub 2} gas, we have extended the scope of this technology to examine hybrid integration of dissimilar device technologies. As a specific example, we demonstrate wafer bonding vertical cavity surface emitting lasers (VCSELs) to transparent AlGaAs and GaP substrates to fabricate bottom-emitting short wavelength VCSELs. As a baseline fabrication technology applicable to many semiconductor systems, wafer fusion will revolutionize the way we think about possible semiconductor devices, and enable novel device configurations not possible by epitaxial growth.

In this combination background and position paper, the authors argue that careful work is needed to develop accurate methods for relating the results of fine-scale numerical simulations of material processes to meaningful values of macroscopic properties for use in constitutive models suitable for finite element solid mechanics simulations. To provide a definite context for this discussion, the problem is couched in terms of the lack of general objective criteria for identifying the size of the representative volume (RV) of a material. The objective of this report is to lay out at least the beginnings of an approach for applying results and methods from statistical physics to develop concepts and tools necessary for determining the RV size, as well as alternatives to RV volume-averaging for situations in which the RV is unmanageably large. The background necessary to understand the pertinent issues and statistical physics concepts is presented.

This report is a cradle-to-grave fabrication and postmortem analysis of a sodium-filled heat pipe solar receiver. The Stirling Thermal Motors Gen. H engine was tested with the Thermacore, Inc. heat pipe receiver on Sandia's Test Bed Concentrator II in the fall of 1996. Although engine performance was significantly increased relative to a direct insolation version of the receiver, hot spots did develop on the heat pipe receiver dome. Over the course of a couple of weeks, after tests were completed, the sodium was distilled out of this receiver, and the front dome was removed. Several failure spots and/or cracks (dubbed volcanoes ) were present on the surface of the wick. Postmortem analysis indicates that the cracks in the wick of the heat pipe are not a product of corrosive oxide action. Voids formed within the wick (created either by mechanical or thermal means) serve to concentrate phosphorous from the electroless plating into the liquid sodium. The presence of phosphorous has an apparently harmful effect on the wick. Examination of a virgin piece of the nickel wick material treated in the same manner as the bulk, prior to the introduction of sodium, would be the best baseline sample for comparison. This sample could be analyzed for phosphorous migration into the wick and determine if there is any initial crack formation from the sintering process. Utiortunately a sample of this material was not available during the preparation of this report. Continued work to determine the mechanism of crack formation could significantly increase the hours of available lifetime testing for future solar thermal heat pipe receivers

A tutorial is presented discussing the basic issues associated with propagation of uncertainty analysis and statistical validation of engineering and scientific models. The propagation of uncertainty tutorial illustrates the use of the sensitivity method and the Monte Carlo method to evaluate the uncertainty in predictions for linear and nonlinear models. Four example applications are presented; a linear model, a model for the behavior of a damped spring-mass system, a transient thermal conduction model, and a nonlinear transient convective-diffusive model based on Burger's equation. Correlated and uncorrelated model input parameters are considered. The model validation tutorial builds on the material presented in the propagation of uncertainty tutoriaI and uses the damp spring-mass system as the example application. The validation tutorial illustrates several concepts associated with the application of statistical inference to test model predictions against experimental observations. Several validation methods are presented including error band based, multivariate, sum of squares of residuals, and optimization methods. After completion of the tutorial, a survey of statistical model validation literature is presented and recommendations for future work are made.

In this paper, we report details of our computational study of two shock wave physics experiments performed on the Sandia Z machine in 1998. The novelty of these particular experiments is that they represent the first successful appli- cation of VISAR interferometry to diagnose shock waves generated in experi- mental payloads by the primary X-ray pulse of the machine. We use the Sandia shock-wave physics code ALEGRA to perform the simulations reported in this study. Our simulations are found to be in fair agreement with the time-resolved VISAR experimental data. However, there are also interesting and important discrepancies. We speculate as to future use of time-resolved shock wave data to diagnose details of the Z machine X-ray pulse in the future.

Optical Micro Electro Mechanical Systems (Optical MEMS) Technology holds the promise of one-day producing highly integrated optical systems on a common, monolithic substrate. The choice of fabrication technology used to manufacture Optical MEMS will play a pivotal role in the size, functionality and ultimately the cost of optical Microsystems. By leveraging the technology base developed for silicon integrated circuits, large batches of routers, emitters, detectors and amplifiers will soon be fabricated for literally pennies per part. In this article we review the current status of technologies used for Optical MEMS, as well as fabrication technologies of the future, emphasizing manufacturable surface micromachining approaches to producing reliable, low-cost devices for optical communications applications.

The Sandia National Laboratories (SNL) Data Encryption Standard (DES) Application Specific Integrated Circuit (ASIC) is the fastest known implementation of the DES algorithm as defined in the Federal Information Processing Standards (FIPS) Publication 46-2. DES is used for protecting data by cryptographic means. The SNL DES ASIC, over 10 times faster than other currently available DES chips, is a high-speed, filly pipelined implementation offering encryption, decryption, unique key input, or algorithm bypassing on each clock cycle. Operating beyond 105 MHz on 64 bit words, this device is capable of data throughputs greater than 6.7 Billion bits per second (tester limited). Simulations predict proper operation up to 9.28 Billion bits per second. In low frequency, low data rate applications, the ASIC consumes less that one milliwatt of power. The device has features for passing control signals synchronized to throughput data. Three SNL DES ASICS may be easily cascaded to provide the much greater security of triple-key, triple-DES.

We have observed low threshold operation of a broadly tunable (2.18-3.4 µm) pump-resonant cw periodically poled lithium niobate (PPLN) optical parametric oscillator (OPO). When pumped at 806 nm with 410 mW from a custom-built diode laser the OPO generated 20 mW of idler output at 3.3 µm.

Anisotropic, smooth etching of the group-III nitrides has been reported at relatively high rates in high-density plasma etch systems. However, such etch results are often obtained under high de-bias andlor high plasma flux conditions where plasma induced damage can be significant. Despite the fact that the group-III nitrides have higher bonding energies than more conventional III-V compounds, plasma-induced etch damage is still a concern. Attempts to minimize such damage by reducing the ion energy or increasing the chemical activity in the plasma often result in a loss of etch rate or anisotropy which significantly limits critical dimensions and reduces the utility of the process for device applications requiring vertical etch profiles. It is therefore necessary to develop plasma etch processes which couple anisotropy for critical dimension and sidewall profile control and high etch rates with low-damage for optimum device performance. In this study we report changes in sheet resistance and contact resistance for n- and p-type GaN samples exposed to an Ar inductively coupled plasma (ICP). In general, plasma-induced damage was more sensitive to ion bombardment energies as compared to plasma flux. In addition, p-GaN was typically more sensitive to plasma-induced damage as compared to n-GaN.

We are developing a method for the real-time analysis of airborne microparticles based on laser ablation mass spectroscopy. Airborne particles enter an ion trap mass spectrometer through a differentially-pumped inlet, are detected by light scattered from two CW laser beams, and sampled by a 10 ns excimer laser pulse at 308 nm as they pass through the center of the ion trap electrodes. After the laser pulse, the stored ions are separated by conventional ion trap methods. In this work thousands of positive and negative ion spectra were collected for eighteen different species: six bacteria, six pollen, and six particulate samples. The data were then averaged and analyzed using the Multivariate Patch Algorithm (MPA), a variant of traditional multivariate anal ysis. The MPA correctly identified all of the positive ion spectra and 17 of the 18 negative ion spectra. In addition, when the average positive and negative spectra were combined the MPA correctly identified all 18 species. Finally, the MPA is also able to identify the components of computer synthesized mixtures of the samples studied

We study the low-temperature in-plane magnetoresistance of tunnel-coupled quasi-one-dimensional quantum wires. The wires are defined by two pairs of mutually aligned split gates on opposite sides of a < 1 micron thick AlGaAs/GaAs double quantum well heterostructure, allowing independent control of their widths. In the ballistic regime, when both wires are defined and the field is perpendicular to the current, a large resistance peak at ~6 Tesla is observed with a strong gate voltage dependence. The data is consistent with a counting model whereby the number of subbands crossing the Fermi level changes with field due to the formation of an anticrossing in each pair of 1D subbands.

On November 23, 1998, an 18,000-foot-deep wild-cat natural gas well being drilled near Bakersfield, CA blew out and caught fire. All attempts to kill this well failed, and the well continues to flow under limited control, producing large volumes of natural gas, salt water, and some oil. The oil and some of the water is being separated and trucked off site, and the remaining gas and water is being burned at the well head. A relief well is being drilled approximately one-quarter mile away in an attempt to intercept the first well. If the relief well is successful, it will be used to cement in and kill the first well. Epoch Wellsite Services, Inc., the mud-logging company for the initial well and the relief well, requested Sandia's rolling float meter (RFM) for these critical drilling operations. The RFM is being used to measure the mud outflow rate and detect kicks while drilling the relief well, which will undoubtedly encounter reservoir conditions similar to those responsible for the blow out. Based on its prior experience with the RFM, Epoch believes that it is the only instrument capable of providing the level of accuracy and response to mudflow needed to quickly detect kicks and minimize the risk of a blowout on this second critical well. In response to the urgent request from industry, Sandia and Epoch technicians installed the RFM on the relief well return line, and completed its initial calibration. The data from the RFM is displayed in real-time for the driller, the companyman, and the toolpusher via Epochs RIGWATCH Drilling Instmmentation System. The RFM has already detected several small kicks while drilling toward the annulus of the blown out well. A conventional paddle meter is located downstream of the RFM to provide redundancy and the opportunity to compare the two meters in an actual drilling operation, The relief well is nearing 14,000 feet deep, targeting an intercept of the first well near 17,600 feet. The relief well is expected to be completed in about 30 days. Several other Sandia instruments being developed for geothermal drilling are also being evaluated during this operation, Successful performance of these instruments on this important drilling job will reinforce our efforts to commercialize this technology for the geothermal and oil and gas drilling industries. Sandia's Rolling Float Meter was developed through the Lost Circulation Technology Program sponsored by the U. S. Department of Energy, Office of Geothermal Technologies. It monitors drilling fluid returns to rapidly detect loss of circulation during geothermal drilling. Lost circulation is particularly prevalent in geothermal wells, and can add as much as 10% to the total cost of drilling the well. Consequently, rapid detection and treatment of lost circulation is necessary for cost- effective geothermal drilling. Sandia has been evaluating and demonstrating the capabilities of the RFM to the geothermal industry for several years. In addition to lost circulation, the RFM is also useful for accurately detecting well kicks. Contacts have been made with mud logging companies that are involved with both geothermal and oil and gas drilling operations.

Microstructure in the reaction interface between molten Al and dense mullite have been studied by transmission electron microscopy to provide insight into mechanisms for forming ceramic-metal composites by reactive metal penetration. The reactions, which have the overall stoichiometry, 3Al#iz01~ + (8+ x)A1 + 13 AlzO~ + xA1 + 6Si, were carried out at temperatures of 900, 1100, and 1200oC for 5 minutes and 60 minutes, and 1400oC for 15 minutes. Observed phases generally were those given in the above reaction, although their proportions and interracial rnicrostructures differed strongly with reaction temperature. After reaction at 900oC, a thin Al layer separated unreacted mullite from the cx-AlzO~ and Al reaction products. No Si phase was found near the reaction front. After 5 minutes at 1100"C, the nxtction front contained Si, ct-A120~, and an aluminum oxide phase with a high concentration of Si. After 60 minutes at 11O(YC many of the cx-A120g particles were needle-shaped with a preferred orientation. After reaction at 1200oC, the reaction front contained a high density of Si particles that formed a continuous layer over many of the mullite grains. The sample reacted at 140VC for 15 minutes had a dense ct-A120J reaction layer less than 2~m thick. Some isolated Si particles were present between the a-AlzO~ layer and the unreacted mullite. Using previously measured reaction kinetics data, the observed temperature dependence of the interracial microstructure have been modeled as three sequential steps, each one of which is rate-limiting in a different temperature range.

Arbitrary Lagrangian Eulerian (ALE) computational techniques allow treatment of gases, liq- uids, and solids in the same simulation. ALE methods include the ability to treat shockwaves in gases, liquids, and solids and the interaction of shockwaves with each other and with media from one of the other categories. ALE codes can also treat explosive detonation and the expansion of the explosive gases and their interaction with air and solids. ALEGRA is a 3-DALE code that has been developed at Sandia National Laboratories over the past few years. ALEGRA has been applied to a 2-D simulation of presplitting using decoupled explosives in rock blasting with very interesting results. The detonation of the explosive at the bottom of the hole sends a shock wave up the borehole driven by the explosive gas expanding into air. The explosive gas compresses the air against the stemming column where it rebounds and recompresses at the bottom of the borehole. This type of ringing takes several cycles to damp out. The explosively induced expansion of the borehole is also treated by ALEGRA as well as the shock wave imparted to the rock. The presentation of this paper will include sev- eral computer animations to aid in understanding this complex phenomenon.

This criticality safety analysis is performed to determine the effective multiplication factor (k_eff) for a storage cabinet filled with unirradiated Cintichem-type targets. These targets will be used to produce ⁹⁹Mo at Sandia National Laboratories and will be stored on-site prior to irradiation in the Annular Core Research Reactor. The analysis consisted of using the Monte Carlo code MCNP (Version 4A) to model and predict the k_eff for the proposed dry storage configuration under credible loss of geometry and moderator control. Effects of target pitch, non-uniform loading, and target internal/external flooding are evaluated. Further studies were done with deterministic methods to verify the results obtained from MCNP and to obtain a clearer understanding of the parameters affecting system criticality. The diffusion accelerated neutral particle transport code ONEDANT was used to model the target in a one-dimensional, infinite half-slab geometry and determine the critical slab thickness. Hand calculations were also completed to determine the critical slab thickness with modified one-group, and one-group, two region approximations. Results obtained from ONEDANT and the hand calculations were compared to applicable cases in a commonly used criticality safety analysis handbook. Overall, the critical slab thicknesses obtained in the deterministic analysis were much larger than the dimensions of the cabinet and further support the predictions by MCNP that a critical system cannot be attained for the base case or in conditions where loss of geometry and moderation control occur.

Localization of light to less than a cubic wavelength, {lambda}{sup 3}, has important quantum consequences. The creation of single mode cavities and the modification of spontaneous emission are two important examples. A defect formed inside a three-dimensional (3D) photonic crystal provides an unique optical environment for light localization. Single mode defect cavities were built, for the first time, from an infrared 3D photonic crystal. A cavity state with modal volume of less than one {lambda}{sup 3} was observed.

Two main assumptions which underlie the Stoney formula relating substrate curvature to mis-match strain in a bonded thin film are that the film is very thin compared to the substrate, and the deformations are infinitesimally small. Expressions for the curvature-strain relastionship are derived for cases in which thses assumptions are relaxed, thereby providing a biasis for interpretation of experimental observations for a broader class of film-substrate configurations.

The formation of quantum wires has much interest due to their novel electronic properties which may lead to enhanced optoelectronic device performance and greater photovoltaic efficiencies. One method of forming these structures is through spontaneous lateral modulation found during the epitaxial growth of III/V alloys. In this paper, we report and summarize our investigations on the formation of lateral moduation in the MBE grown InAlAs/InP(001) system. This system was grown as a short-period superlattice where n-monolayers of InAs are deposited followed by m-Monolayers of AlAs (with n and m~2) and this sequence is repeated to grown a low strain InAlAs ternary alloy on InP(001) that exhibits lateral modulation. Films were grown under a variety of condition (growth temperature, effective alloy composition, superlattice period, and growth rate). These films have been extensively analyzed using X-ray diffraction, atomic force microscopy, and transmission electron microscopy (TEM) and microcharacterization, in addition to photon-based spectroscopes. Here we present results of several microstructural characterizations using a wide range of TEM-based techniques, and compare them to results from the other methods to obtain a unified understanding of composition modulation. Two strong points consistently emerge: 1) The lateral modulation wavelength is insensitive to growth temperature and effective alloy composition, but the strength of the lateral modulation is greatest near an effective alloy composition of In(0.46)Al(0.54)As, which corresponds to a slightly tensile global strain with respect to InP. 2) The composition variation for the strongly modulated films is as much as 0.38 InAs mole fraction. In addition, for these strongly modulated films, the modulation wave is asymmetric showing strongly peaked, narrower InAs-rich regions separated by flat AlAs-rich regions. We discuss these results and their possible implications in addition to detailing the techniques used to obtain them.

Pattern formation on surfaces undergoing low-energy ion bombardment is a common phenomenon. Here, a recently developed in situ spectroscopic light scattering technique was used to monitor periodic ripple evolution on Si(001) during Ar(+) sputtering. Analysis of the rippling kinetics indicated that under high flux sputtering at low temperatures the concentration of mobile species on the surface is saturated, and, surprisingly, is both temperature and ion flux independent. This is due to an effect of ion collision cascades on the concentration of mobile species. This new understanding of surface dynamics during sputtering allowed us to measure straighforwardly the activation energy for atomic migration on the surface to be 1.2+0.1 eV. The technique is generalizable to any material, including high temperature and insulating materials for which surface migration energies are notoriously difficult to measure.

The suitability of the wavelength range provided by silicon photodiode detector arrays for monitoring the spectral reflectance during epitaxial growth of GaSb, AlGaAsSb, and GaInAsSb, which have cutoff wavelengths at 25 degree C of 1.7, 1.2, and 2.3 um, respectively, is demonstrated. These alloys were grown lattice matched to GaSb in a vertical rotating-disk reactor, which was modified to accommodate near normal reflectance without affecting epilayer uniformity, By using a virtual interface model, the growth rate and complex refractive index at the growth temperature are extracted for these alloys over the 600 to 1000 nm spectral range. Excellent agreement is obtained between the extracted growth rate and that determined by ex-situ measurement.

The porosities of three mesoporous silica materials were characterized with {sup 129}Xe NMR spectroscopy. The materials were synthesized by a sol-gel process with r = 0, 25, and 70% methanol by weight in an aqueous cetyltrimethylammonium bromide solution. Temperature dependent chemical shifts and spin lattice relaxation times reveal that xenon does not penetrate the pores of the largely disordered (r= 70%) silica. For both r = 0 and 25%, temperature dependent resonances corresponding to physisorbed xenon were observed. An additional resonance for the r = 25% sample was attributed to xenon between the disordered cylindrical pores. 2D NMR exchange experiments corroborate the spin lattice relaxation data which show that xenon is in rapid exchange between the adsorbed and the gas phase.

The authors present a compact, robust, solid-state blue light (490 nm) source capable of greater than 5 mW of output in a TEM{sub 00} mode. This device is an optically pumped, vertical external-cavity surface-emitting laser (VECSEL) with an intracavity frequency doubling crystal.

Deposition parameters were found to have a marked effect on piezoelectric response of reactive radio frequency (RF) sputtered AlN thin films. The authors observed peizoelectric response values ranging from {minus}3.5 to +4.2 pm/V for 1 {micro}m thick AlN films deposited onto Ti/Ru electrode stacks. An investigation of the effects of deposition parameters, in particular the nature of the Ru/AlN interface, was conducted. The lag time between deposition of adjacent thin film layers appeared to have the greatest affect on the value of the piezoelectric response. This suggests that chemical reaction occurring on the Ru thin film surface is responsible for changing an important thin film property such as dipole orientation within the overlying AlN thin film.

In this paper, we introduce a new approach for altering the properties of bridged polysilsesquioxane xerogels using post-processing modification of the polymeric network. The bridging organic group contains latent functionalities that can be liberated thermally, photochemically, or by chemical means after the gel has been processed to a xerogel. These modifications can produce changes in density, volubility, porosity, and or chemical properties of the material. Since every monomer possesses two latent functional groups, the technique allows for the introduction of high levels of functionality in hybrid organic-inorganic materials. Dialkylenecarbonate-bridged polysilsesquioxane gels were prepared by the sol-gel polymerization of bis(triethoxysilylpropyl)carbonate (1) and bis(triethoxysilylisobutyl)-carbonate (2). Thermal treatment of the resulting non-porous xerogels and aerogels at 300-350 C resulted in quantitative decarboxylation of the dialkylenecarbonate bridging groups to give new hydroxyalkyl and olefinic substituted polysilsesquioxane monolithic xerogels and aerogels that can not be directly prepared through direct sol-gel polymerization of organotrialkoxysilanes.

JavaScript allows the definition and use of large, complex objects. Unlike some other object-oriented languages, it also allows run-time modifications not only of the values of object components, but also of the very structure of the object itself. This feature is powerful and sometimes very convenient, but it can be difficult to keep track of the object's structure and values throughout program execution. What's needed is a simple way to view the current state of an object at any point during execution. There is a debug function that is included in the Netscape server-side JavaScript environment. The function outputs the value(s) of the expression given as the argument to the function in the JavaScript Application Manager's debug window [SSJS].

Traditional safety and reliability analysis methods are applicable to many standard problems, including those examples illustrated in most formal courses. However, there are many real-world situations for which non-traditional methods appear to be more appropriate, mainly because most practical problems involve substantial subjectivity about the inputs and models used. This paper surveys some of the most applicable approaches found in a recent research study. Each approach is developed individually and is illuminated by selecting example situations of apparent applicability. Then, the combinational blending of the approaches with each other and with traditional methodology is discussed.

Work of adhesion (Wa) measurements are being studied for several types of polymer/metal combinations in order to obtain a better understanding of the adhesive failure mechanisms for systems containing encapsulated and bonded components. A primary concern is whether studies of model systems can be extended to systems of technological interest. One study performed in our laboratory involved the determination of Wa between silicone (PDMS) and Al surfaces in order to establish potential adhesive failure mechanisms. Our initial work with PDMS was based on Dow Corning 170 Sylgard. PDMS hemispheres were synthesized following the procedure outlined by Chaudhury and Whitesides where the filler was stripped from the commercial silicone by centrifuging. Wa between PDMS surfaces was determined using the JKR method. Our results for the Wa of PDMS were in agreement with those reported by Chaudhury and Whitesides. However, further JKR studies using these PDMS hemispheres on flat Al surfaces were fraught with difficulty. We could not discriminate hydrogen-bonding effects between Al{sub 2}O{sub 3} and hydroxyl groups in the PDMS and other possible bonding mechanisms. It was suggested that commercial systems contain inhibitors and additives that interfere with understanding the PMDS/Al interface. Therefore, the current study uses pure PDMS networks synthesized in our lab. Also, two contact mechanics methods were deployed to measure the Wa--JKR method using two hemispheres and a LEFM method using a cylinder containing a circumferential crack. This paper contains a description of the synthesis of the PDMS used for these studies and the determination of Wa between PDMS surfaces using the JKR method, contact angle measurements, and a LEFM method that consists of a cylinder containing a circumferential crack.

This editorial paper presents a vision for intelligent health care in the home of the future, focusing on technologies with the highest potential payoff given targeted government funding over the next ten years. A secure, plug-and-play information framework provides the starting point for identifying technologies that must be developed before home-based devices can know their context and assimilate information to support care decisions.

We propose an object-oriented information architecture for telemedicine systems that promotes secure `plug-and-play' interaction between system components through standardized interfaces, communication protocols, messaging formats, and data definitions. In this architecture, each component functions as a black box, and components plug together in a ''lego-like'' fashion to achieve the desired device or system functionality. Introduction Telemedicine systems today rely increasingly on distributed, collaborative information technology during the care delivery process. While these leading-edge systems are bellwethers for highly advanced telemedicine, most are custom-designed and do not interoperate with other commercial offerings. Users are limited to a set of functionality that a single vendor provides and must often pay high prices to obtain this functionality, since vendors in this marketplace must deliver en- tire systems in order to compete. Besides increasing corporate research and development costs, this inhibits the ability of the user to make intelligent purchasing decisions regarding best-of-breed technologies. This paper proposes a reference architecture for plug-and-play telemedicine systems that addresses these issues.

Global Nuclear Materials Management (GNMM) anticipates and supports a growing international recognition of the importance of uniform, effective management of civilian, excess defense, and nuclear weapons materials. We expect thereto be a continuing increase in both the number of international agreements and conventions on safety, security, and transparency of nuclear materials, and the number of U.S.-Russian agreements for the safety, protection, and transparency of weapons and excess defense materials. This inventory of agreements and conventions may soon expand into broad, mandatory, international programs that will include provisions for inspection, verification, and transparency, To meet such demand the community must build on the resources we have, including State agencies, the IAEA and regional organizations. By these measures we will meet the future expectations for monitoring and inspection of materials, maintenance of safety and security, and implementation of transparency measures.

Sandia has implemented a formal process to verify that new or modified facilities and operations are ready to safely operate. The readiness review process focuses on the status of management systems, personnel, and systems, structures, and components to do work safely. The scope and depth of the review are tailored to match the potential consequences and the likelihood that the consequences could occur. The precepts and methodology of the process are applicable to verifying the readiness of enterprise systems, and should comprise the final element in developing and implementing an enterprise system. This paper describes the readiness review process, the key elements for success, lessons learned from Sandia's readiness assessment process, and outlines how the process can be applied to enterprise systems. Specific topics addressed include selecting the criteria, approach, and lines of inquiry to be used for the review; selecting members for the review team; team leader responsibilities; reporting and closing deficiencies; and, responsibilities of the facility/project owner and management.

Irradiation of red meat and poultry has been approved by the U.S. FDA, and the U.S. Department of Agriculture's rule for processing red meat is out for comment. Looking beyond the current issues of packaging materials, labeling, and consumer acceptance, this paper reviews the next step of implementation and how to remove, or at least reduce, the barriers to utilization. Polls of the user community identified their requirements for electron beam or x-ray processing of meat or poultry and their concerns about implementation for on-line processing. These needs and issues are compared to the capabilities of the accelerator industry. The critical issues of beam utilization and dose uniformity, factors affecting floor space requirements, and treatment costs are examined.

Boolean logic expressions are often derived in safety and reliability analysis. Since the values of the operands are rarely exact, accounting for uncertainty with the tightest justifiable bounds is important. Accurate determination of result bounds is difficult when the inputs have constraints. One example of a constraint is that an uncertain variable that appears multiple times in a Boolean expression must always have the same value, although the value cannot be exactly specified. A solution for this repeated variable problem is demonstrated for two Boolean classes. The classes, termed functions with unate variables (including, but not limited to unate functions), and exclusive-or functions, frequently appear in Boolean equations for uncertain outcomes portrayed by logic trees (event trees and fault trees).

This paper presents results from a series of preliminary tests to evaluate a scannerless range-imaging device as a potential sensory enhancement tool for divers and as a potential identification sensor for deployment on small unmanned underwater vehicles. The device, developed by Sandia National Laboratories, forms an image on the basis of point-to-point range to the target rather than an intensity map. The range image is constructed through a classical continuous wave phase detection technique in which the light source is amplitude modulated at radio frequencies. The receiver incorporates a gain-modulated image intensifier, and range information is calculated on the basis of the phase difference between the transmitted and reflected signal. The initial feasibility test at the Coastal Systems Station showed the device to be effective at imaging low-contrast underwater targets such as concertina wire. It also demonstrated success at imaging a 21-inch sphere at a depth of 10 feet in the water column through a wavy air-water interface.

In 1991, the Federal Aviation Administration (FAA) established an Airworthiness Assurance NDI Validation Center (AANC) at Sandia National Laboratories. Its primary mission is to support technology development, validation, and transfer to industry in order to enhance the airworthiness and improve the aircraft maintenance practices of the U.S. commercial aviation industry. The Center conducts projects in a myriad of engineering disciplines. The results are placed in the public domain so that the industry at-large can reap the benefits of FAA-funded Research and Development efforts. To support the Center's goals, the FAA/AANC has set up a hangar facility at the Albuquerque International Airport which contains a collection of transport and commuter aircraft as well as other test specimens. The facility replicates a working maintenance environment by incorporating both the physical inspection difficulties as well as the environmental factors which influence maintenance reliability.

Over a period of 15 months, five sets of adhesively-bonded butt joints were fabricated and tested. This previously unreported data is used to assess the variability of measured interface corner toughness values, K{sub ac}, as well as the dependence of K{sub ac} on surface preparation. A correlation between K{sub ac} and the size of the adhesive failure zone is also noted.

The authors consider a chain of elastic (Hertzian) grains that repel upon contact according to the potential V = a{delta}{sup u}, u > 2, where {delta} is the overlap between the grains. They present numerical and analytical results to show that an impulse initiated at an end of a chain of Hertzian grains in contact eventually propagates as a soliton for all n > 2 and that no solitons are possible for n {le} 2. Unlike continuous, they find that colliding solitons in discrete media initiative multiple weak solitons at the point of crossing.

Abstract not provided.

This paper outlines general physical and computational issues associated with performing numerical simulation of fire suppression. Fire suppression encompasses a broad range of chemistry and physics over a large range of time and length scales. The authors discuss the dominant physical/chemical processes important to fire suppression that must be captured by a fire suppression model to be of engineering usefulness. First-principles solutions are not possible due to computational limitations, even with the new generation of tera-flop computers. A basic strategy combining computational fluid dynamics (CFD) simulation techniques with sub-grid model approximations for processes that have length scales unresolvable by gridding is presented.

As we enter the new millennium, let us recognize that the losses resulting from natural or malevolent events that cause major property damage, severe injuries, and unnecessary death are not always due to forces beyond our control. We can prevent these losses by changing the way we think and act about design and construction projects. New tools, technologies, and techniques can improve structural safety, security, and reliability and protect owners, occupants, and users against loss and casualties. Hurricane Mitch, the African embassy bombings, the ice storms in Canada and the northeastern US last winter, the Oklahoma City bombing, flooding and earthquakes in California, tornadoes and flooding in Florida, and wildfires in the Southwest are threats to the safety and security of the public and the reliability of our constructed environment. Today's engineering design community must recognize these threats and address them in our standards, building codes, and designs. We know that disasters will continue to strike and we must reduce their impact on the public. We must demand and create innovative solutions that assure a higher level of structural performance when disasters strike.

Z-pinches created using the Z accelerator generate {approximately}220 TW, 1.7 MJ radiation pulses that heat large ({approximately}10 cm{sup 3}) hohlraums to 100-150 eV temperatures for times of order 10 nsec. We are performing experiments exploiting this intense radiation to drive shock waves for equation of state studies. The shock pressures are typically 1-10 Mbar with 10 nsec duration in 6-mm-diameter samples. In this paper we demonstrate the ability to perform optical spectroscopy measurements on shocked samples located in close proximity to the z-pinch. These experiments are particularly well suited to optical spectroscopy measurements because of the relatively large sample size and long duration. The optical emission is collected using fiber optics and recorded with a streaked spectrograph. Other diagnostics include VISAR and active shock breakout measurements of the shocked sample and a suite of diagnostics that characterize the radiation drive. Our near term goal is to use the spectral emission to obtain the temperature of the shocked material. Longer term objectives include the examination of deviations of the spectrum from blackbody, line emission from lower density regions, determination of kinetic processes in molecular systems, evaluation of phase transitions such as the onset of metalization in transparent materials, and characterization of the plasma formed when the shock exits the rear surface. An initial set of data illustrating both the potential and the challenge of these measurements is described.

Sandia Laboratories' computational scientists are addressing a very important question: How do we get insight from the human combined with the computer-generated information? The answer inevitably leads to using scientific visualization. Going one technology leap further is teraflop visualization, where the computing model and interactive graphics are an integral whole to provide computing for insight. In order to implement our teraflop visualization architecture, all hardware installed or software coded will be based on open modules and dynamic extensibility principles. We will illustrate these concepts with examples in our three main research areas: (1) authoring content (the computer), (2) enhancing precision and resolution (the human), and (3) adding behaviors (the physics).

Over the past two years, New Mexico has been engaged in a significant new approach to implement large purchases of solar power. This effort followed a regulatory process that treated solar power generation similar to conventional generation obtained by an investor-owned utility under the regulation of a public utility commission. In 1997, Public Service Company of New Mexico (PNM) gained approval to purchase power from a 100-MW combustion turbine facility that would be owned and operated by a wholesale generator. At the same time it issued the approval, and following discussions with the utility, the New Mexico Public Utility Commission (NMPUC) also required PNM to issue a request for proposal for a 5-MW central station solar facility, a major step for solar technologies in the state, in what would be the world's largest of its technology type. In cooperation with the staff of the NMPUC, PNM reviewed the proposals received, and Applied Power Corporation was selected for the photovoltaic portion of the proposed plan; retaining ownership of the plant, assuming the risks connected with the technology, and operating the plant in exchange for a power purchase agreement in a first-of-its-kind contract for photovoltaics. During the NMPUC hearings, various parties raised significant opposition to the cost-recovery mechanism that was proposed and voiced issues about the type of solar plant, its size, cost and the tiding approaches to building it. Because of these issues, alternative proposals were put forth that reduced the size and costs of the plant and had implied changes in ownership and risks. The order issued by the NMPUC on October 21, 1998, requires PNM to impose a charge of 0.5% on its retail electric customers' monthly bills to be used to acquire the solar facilities, but also to obtain other renewable electric power resources, both on a pay-as-you-go basis. This paper identifies the issues and their resolution that similar projects are expected to encounter.

We conducted three sets of depth-of-penetration experiments with limestone targets and 3.0 caliber-radius-head (CRH), ogive-nose steel rod projectiles. The limestone targets had a nominal unconfined compressive strength of 60 MPa, a density of 2.31 kg/m{sup 3}, a porosity of 15%, and a water content less than 0.4%. The ogive-nose rod projectiles with length-to-diameter ratios often were machined from 4340 R{sub c} 45 and Aer Met 100 R{sub c} 53 steel, round stock and had diameters and masses of 7.1 mm, 0.020 kg; 12.7 mm, 0.117 kg; and 25.4 mm, 0.931 kg. Powder guns or a two-stage, light-gas gun launched the projectiles at normal impacts to striking velocities between 0.4 and 1.9 km/s. For the 4340 R{sub c} 45 and Aer Met 100 R{sub c} 53 steel projectiles, penetration depth increased as striking velocity increased to a striking velocity of 1.5 and 1.7 km/s, respectively. For larger striking velocities, the projectiles deformed during penetration without nose erosion, deviated from the shot line, and exited the sides of the target. We also developed an analytical penetration equation that described the target resistance by its density and a strength parameter determined from depth of penetration versus striking velocity data.

The delivery of the first one tera-operations/sec computer has significantly impacted production data visualization, affecting data transfer, post processing, and rendering. Terascale computing has motivated a need to consider the entire data visualization system; improving a single algorithm is not sufficient. This paper presents a systems approach to decrease by a factor of four the time required to prepare large data sets for visualization.For daily production use, all stages in the processing pipeline from physics simulation code to pixels on a screen, must be balanced to yield good overall performance. Also, to complete the data path from screen to the analyst's eye, user display systems for individuals and teams are examined. Performance of the initial visualization system is compared with recent improvements. Lessons learned from the coordinated deployment of improved algorithms are also discussed, including the need for 64 bit addressing and a fully parallel data visualization pipeline.

An evaluation of biotic and abiotic attenuation processes potentially important to chlorinated and non-chlorinated volatile organic compound (VOC) fate and transport in the 148 meter thick vadose zone beneath the Chemical Waste Landfill (CWL) was conducted. A unique feature of this evaluation is the comparison of two estimates of VOC mass present in the soil gas, pore-water, and solid phases (but not including mass as non-aqueous phase liquid [NAPL]) of the vadose zone in 1993. One estimate, 1,800 kg, was obtained from vadose zone transport modeling that incorporated molecular diffusion and volatilization to the atmosphere, but not biotic or chemical processes. The other estimate, 2,120 kg, was obtained from the sum of VOC mass physically removed during soil vapor extraction and an estimate of VOC mass remaining in the vadose zone in 1998, both adjusted to exclude NAPL mass. This comparison indicates that biogeochemical processes were at best slightly important to historical VOC plume development. Some evidence of aerobic degradation of non-chlorinated VOCs and abiotic transformation of 1,1,1-Trichloroethane was identified. Despite potentially amenable site conditions, no evidence was found of cometabolic and anaerobic transformation pathways. Relying principally on soil-gas analytical results, an upper-bound estimate of 21% mass reduction due to natural biogeochemical processes was developed. Although available information for the CWL indicates that natural attenuation processes other than volatilization to the atmosphere did not effective y enhance groundwater protection, these processes could be important in significantly reducing groundwater contamination and exposure risks at other sites. More laboratory and field research is required to improve our collective ability to characterize and exploit natural VOC attenuation processes, especially with respect to the combination of relatively thick and dry vadose zones and chlorinated VOCs.

Abstract not provided.

Telemedicine technology is rapidly evolving. Whereas early telemedicine consultations relied primarily on video conferencing, consultations today may utilize video conferencing, medical peripherals, store-and-forward capabilities, electronic patient record management software, and/or a host of other emerging technologies. These remote care systems rely increasingly on distributed, collaborative information technology during the care delivery process, in its many forms. While these leading-edge systems are bellwethers for highly advanced telemedicine, the remote care market today is still immature. Most telemedicine systems are custom-designed and do not interoperate with other commercial offerings. Users are limited to a set of functionality that a single vendor provides and must often pay high prices to obtain this functionality, since vendors in this marketplace must deliver entire systems in order to compete. Besides increasing corporate research and development costs, this inhibits the ability of the user to make intelligent purchasing decisions regarding best-of-breed technologies. We propose a secure, object-oriented information architecture for telemedicine systems that promotes plug-and-play interaction between system components through standardized interfaces, communication protocols, messaging formats, and data definitions. In this architecture, each component functions as a black box, and components plug together in a lego-like fashion to achieve the desired device or system functionality. The architecture will support various ongoing standards work in the medical device arena.

The US health care industry is experiencing a substantial paradigm shift with regard to home care due to the convergence of several technology areas. Increasingly-capable telehealth systems and the internet are not only moving the point of care closer to the patient, but the patient can now assume a more active role in his or her own care. These technologies, coupled with (1) the migration of the health care industry to electronic patient records and (2) the emergence of a growing number of enabling health care technologies (e.g., novel biosensors, wearable devices, and intelligent software agents), demonstrate unprecedented potential for delivering highly automated, intelligent health care in the home. This editorial paper presents a vision for the implementation of intelligent health care technology in the home of the future, focusing on areas of research that have the highest potential payoff given targeted government funding over the next ten years. Here, intelligent health care technology means smart devices and systems that are aware of their context and can therefore assimilate information to support care decisions. A systems perspective is used to describe a framework under which devices can interact with one another in a plug-and-play manner. Within this infrastructure, traditionally passive sensors and devices will have read/write access to appropriate portions of an individual's electronic medical record. Through intelligent software agents, plug-and-play mechanisms, messaging standards, and user authentication tools, these smart home-based medical devices will be aware of their own capabilities, their relationship to the other devices in the home system, and the identity of the individual(s) from whom they acquire data. Information surety technology will be essential to maintain the confidentiality of patient-identifiable medical information and to protect the integrity of geographically dispersed electronic medical records with which each home-based system will interact.

A model is developed herein for predicting the mechanical response of inelastic crystalline solids. Particular emphasis is given to the development of microstructural damage along grain boundaries, and the interaction of this damage with intragranular inelasticity caused by dislocation dissipation mechanisms. The model is developed within the concepts of continuum mechanics, with special emphasis on the development of internal boundaries in the continuum by utilizing a cohesive zone model based on fracture mechanics. In addition, the crystalline grains are assumed to be characterized by nonlinear viscoplastic mechanical material behavior in order to account for dislocation generation and migration. Due to the nonlinearities introduced by the crack growth and viscoplastic constitution, a numerical algorithm is utilized to solve representative problems. Implementation of the model to a finite element computational algorithm is therefore briefly described. Finally, sample calculations are presented for a polycrystalline titanium alloy with particular focus on effects of scale on the predicted response.

Application of Executive Order 12898 to risk assessment of highway or rail transport of hazardous materials has proven difficult; the location and conditions affecting the propagation of a plume of hazardous material released in a potential accident are unknown, in general. Therefore, analyses have only been possible in geographically broad or approximate manner. The advent of geographic information systems and development of software enhancements at Sandia National Laboratories have made kilometer-by-kilometer analysis of populations tallied by U.S. Census Blocks along entire routes practicable. Tabulations of total, or racially/ethnically distinct, populations close to a route, its alternatives, or the broader surrounding area, can then be compared and differences evaluated statistically. This paper presents methods of comparing populations and their racial/ethnic compositions using simple tabulations, histograms and Chi Squared tests for statistical significance of differences found. Two examples of these methods are presented: comparison of two routes and comparison of a route with its surroundings.

Epitaxial thin films of the Tl cuprate superconductors Tl{sub 2}Ba{sub 2}CaCu{sub 2}O{sub 8}, Tl{sub 2}Ba{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10}, and TL{sub 0.78}Bi{sub 0.22}Ba{sub 0.4}Sr{sub 1.6}Ca{sub 2}Cu{sub 3}O{sub 9{minus}{delta}} are studied with x-ray photoemission spectroscopy. These data, together with previous measurements in this lab of Tl{sub 2}Ba{sub 2}CuO{sub 6+{delta}} and TlBa{sub 2}CaCu{sub 2}O{sub 7{minus}{delta}}, comprise a comprehensive data set for a comparative study of Tl cuprates with a range of chemical and electronic properties. In the Cu 2p spectra, a larger energy separation between the satellite and main peaks (E{sub s}-E{sub m}) and a lower intensity ratio (I{sub s}/I{sub m}) are found to correlate with higher values of T{sub c}. Analysis of these spectra within a simple configuration interaction model suggests that higher values of T{sub c} are related to low values of the O 2p {r_arrow} Cu 3d charge transfer energy. In the O 1s region, a smaller bond length between Ba and Cu-O planar oxygen is found to correlate with a lower binding energy for the signal associated with Cu-O bonding, most likely resulting from the increased polarization screening by Ba{sup 2+} ions. For samples near optimum doping, maximum T{sub c} is observed to occur when the Tl 4f{sub 7/2} binding energy is near 117.9 eV, which is near the middle of the range of values observed for Tl cuprates. Higher Tl 4f{sub 7/2} binding energies, corresponding to formal oxidation states nearer Tl{sup 1+}, are also found to correlate with longer bond lengths between Ba and Tl-O planar oxygen, and with higher binding energies of the O 1s signal associated with Tl-O bonding.

First-principles total energies of periodic vicinals are used to estimate barriers for Pt-adatom diffusion along straight and kinked steps on Pt(111), and around a corner where straight steps intersect. In all cases studied, hopping diffusion has a lower barrier than concerted substitution. In conflict with simulations of dendritic Pt island formation on Pt(111), hopping from a corner site to a step whose riser is a (111)-micro facet is predicted to be more facile than to one whose riser is a (100).

Scenario development has two primary purposes in the design and documentation of post-closure performance assessments in a regulatory setting. First, scenario development ensures a sufficiently comprehensive consideration of the possible future states of the system. Second, scenario development identifies the important scenarios that must be considered in quantitative analyses of the total system performance assessment (TSPA). Section 2.0 of this report describes the scenario development process. Steps in the process are described in Section 2.1, and terms introduced in this section are defined in Section 2.2. The electronic database used to document the process is described in Section 3, and Section 4 provides a summary of the current status of the YMP scenario development work. Section 5 contains acknowledgments, and Section 6 contains a list of the references cited.

We have discussed two aspects of creating high integrity software that greatly benefit from the availability of transformation technology, which in this case is manifest by the requirement for a sophisticated backtracking parser. First, because of the potential for correctly manipulating programs via small changes, an automated non-procedural transformation system can be a valuable tool for constructing high assurance software. Second, modeling the processing of translating data into information as a, perhaps, context-dependent grammar leads to an efficient, compact implementation. From a practical perspective, the transformation process should begin in the domain language in which a problem is initially expressed. Thus in order for a transformation system to be practical it must be flexible with respect to domain-specific languages. We have argued that transformation applied to specification results in a highly reliable system. We also attempted to briefly demonstrate that transformation technology applied to the runtime environment will result in a safe and secure system. We thus believe that the sophisticated multi-lookahead backtracking parsing technology is central to the task of being in a position to demonstrate the existence of HIS.

We have designed a new class of cyclic siloxane compounds that behave as sol-gel systems when ring open polymerized using a hydroxide base. These monomers polymerize through chain growth polymerization. unlike conventional alkoxysilane sol-gel precursors, to form sol-gel polymers. They do not require solvent or water for polymerization, show no visible shrinkage or cracking during polymerization and are thermally stable. We have successfully utilized these materials in encapsulation of microelectronics. Current efforts are focused toward expanding this family of ROP monomers and optimization of their mechanical properties.

Mission critical applications of MEMS devices require knowledge of the distribution in their material properties and long-term reliability of the small-scale structures. This project reports on a new testing program at Sandia to quantify the strength distribution using samples that reflect the dimensions of critical MEMS components. The strength of polysilicon fabricated with Sandia's SUMMiT 4-layer process was successfully measured using samples with gage sections 2.5 {micro}m thick by 1.7 {micro}m wide and lengths of 15 and 25 {micro}m. These tensile specimens have a freely moving pivot on one end that anchors the sample to the silicon die and prevents off axis loading during testing. Each sample is loaded in uniaxial tension by pulling laterally with a flat tipped diamond in a computer-controlled Nanoindenter. The stress-strain curve is calculated using the specimen cross section and gage length dimensions verified by measuring against a standard in the SEM. The first 48 samples had a means strength of 2.24 {+-} 0.35 GPa. Fracture strength measurements grouped into three strength levels, which matched three failure modes observed in post mortem examinations. The seven samples in the highest strength group failed in the gage section (strength of 2.77 {+-} 0.04 GPa), the moderate strength group failed at the gage section fillet and the lowest strength group failed at a dimple in the hub. With this technique, multiple tests can be programmed at one time and performed without operator assistance at a rate of 20-30 per day allowing the collection of significant populations of data. Since the new test geometry has been proven, the project is moving to test the distributions seen from real geometric features typical to MEMS such as the effect of gage length, fracture toughness, bonding between layers, etch holes, dimples and shear of gear teeth.