Publications

Low Energy Charge-Induced Voltage Alteration (LECIVA) is a new scanning electron microscopy technique developed to localize open conductors in passivated ICs. LECIVA takes advantage of recent experimental work showing that the dielectric surface equilibrium voltage has an electron flux density dependence at low electron beam energies ({le}1.0 keV). The equilibrium voltage changes from positive to negative as the electron flux density is increased. Like Charge-Induced Voltage Alteration (CIVA), LECIVA images are produced from the voltage fluctuations of a constant current power supply as an electron beam is scanned over the IC surface. LECIVA image contrast is generated only by the electrically open part of a conductor, yielding, the same high selectivity demonstrated by CIVA. Because LECIVA is performed at low beam energies, radiation damage by the primary electrons and x-rays to MOS structures is far less than that caused by CIVA. LECIVA may also be performed on commercial electron beam test systems that do not have high primary electron beam energy capabilities. The physics of LECIVA signal generation are described. LECIVA imaging examples illustrate its utility on both a standard scanning electron microscope (SEM) and a commercial electron beam test system.

The arc energy distribution in the electrode gap plays a central role in the vacuum arc remelting (VAR) process. However, very little has been done to investigate the response of this important process variable to changes in process parameters. Emission spectroscopy was used to investigate variations in arc energy in the annulus of a VAR furnace during melting of 0.43 m diameter Alloy 718 electrode into 0.51 in diameter ingot. Time averaged (1 second) intensity data from various chromium atom and ion (Cr{sup +}) emission lines were simultaneously collected and selected intensity ratios were subsequently used as air energy indicators. These studies were carried out as a function of melting current, electrode gap, and CO partial pressure. The data were modeled and the ion electronic energy was found to be a function of electrode gap, the energy content of the ionic vapor decreasing with increasing gap length; the ion ratios were not found to be sensitive to pressure. On the other hand, the chromium atom electronic energy was difficult to model in the factor space investigated, but was determined to be sensitive, to pressure. The difference in character of the chromium ion and atom energy fluctuations in the furnace annulus are attributed to the difference in the origins of these arc species and the non-equilibrium nature of the metal vapor arc. Most of the ion population is emitted directly from cathode spots, whereas much of the atomic vapor arises due to vaporization from the electrode and pool surfaces. Also, the positively charged ionic species interact more strongly with the electron gas than the neutral atomic species, the two distributions never equilibrating due to the low pressure.

The NAVSTAR satellites have two missions: navigation and nuclear detonation detection. The main objective of this paper is to describe one of the key elements of the Nuclear Detonation Detection System (NDS), the Burst Detector W-Sensor (BDW) that was developed for the Air Force Space and Missle Systems Center, its mission on GPS Block IIR, and how it utilizes GPS timing signals to precisely locate nuclear detonations (NUDET). The paper will also cover the interface to the Burst Detector Processor (BDP) which links the BDW to the ground station where the BDW is controlled and where data from multiple satellites are processed to determine the location of the NUDET. The Block IIR BDW is the culmination of a development program that has produced a state-of-the-art, space qualified digital receiver/processor that dissipates only 30 Watts, weighs 57 pounds, and has a 12in. {times} l4.2in. {times} 7.16in. footprint. The paper will highlight several of the key multilayer printed circuit cards without which the required power, weight, size, and radiation requirements could not have been met. In addition, key functions of the system software will be covered. The paper will be concluded with a discussion of the high speed digital signal processing and algorithm used to determine the time-of-arrival (TOA) of the electromagnetic pulse (EMP) from the NUDET.

We are using VUV spectroscopy to study the ion source region on the SABRE applied-B extraction ion diode. The VUV diagnostic views the anode-cathode gap perpendicular to the ion acceleration direction, and images a region 0--1 mm from the anode onto the entrance slit of a I m normal-incidence spectrometer. Time resolution is obtained by gating multiple striplines of a CuI- or MgF{sub 2} -coated micro-channel plate intensifier. We report on results with a passive proton/carbon ion source. Lines of carbon and oxygen are observed over 900--1600 {angstrom}. The optical depths of most of the lines are less than or of order 1. Unfolding the Doppler broadening of the ion lines in the source plasma, we calculate the contribution of the source to the accelerated C IV ion micro-divergence as 4 mrad at peak power. Collisional-radiative modeling of oxygen line intensities provides the source plasma average electron density of 7{times}10{sup 16} cm{sup {minus}3} and temperature of 10 eV Measurements are planned with a lithium ion source and with VUV absorption spectroscopy.

Practical and theoretical limits on the bandwidth of distributed optical phase modulators and traveling-wave photodetectors are given. For the case of perfect velocity matching, RF transmission losses are the main performance-limiting factor. However, some high-performance modulators require highly-capacitive transmission lines making proper slow-wave operation difficult to achieve.

This report documents the results of a study regarding the conservatisms in ASME Code Section 3, Class 1 component fatigue evaluations and the effects of Light Water Reactor (LWR) water environments on fatigue margins. After review of numerous Class 1 stress reports, it is apparent that there is a substantial amount of conservatism present in many existing component fatigue evaluations. With little effort, existing evaluations could be modified to reduce the overall predicted fatigue usage. Areas of conservatism include design transients considerably more severe than those experienced during service, conservative grouping of transients, conservatisms that have been removed in later editions of Section 3, bounding heat transfer and stress analysis, and use of the ``elastic-plastic penalty factor`` (K{sub 3}). Environmental effects were evaluated for two typical components that experience severe transient thermal cycling during service, based on both design transients and actual plant data. For all reasonable values of actual operating parameters, environmental effects reduced predicted margins, but fatigue usage was still bounded by the ASME Section 3 fatigue design curves. It was concluded that the potential increase in predicted fatigue usage due to environmental effects should be more than offset by decreases in predicted fatigue usage if re-analysis were conducted to reduce the conservatisms that are present in existing component fatigue evaluations.

Abstract not provided.

Austin chalk core has been tested to determine the effective law for deformation of the matrix material and the stress-sensitive conductivity of the natural fractures. For deformation behavior, two samples provided data on the variations of the poroelastic parameter, {alpha}, for Austin chalk, giving values around 0.4. The effective-stress-law behavior of a Saratoga limestone sample was also measured for the purpose of obtaining a comparison with a somewhat more porous carbonate rock. {alpha} for this rock was found to be near 0.9. The low {alpha} for the Austin chalk suggests that stresses in the reservoir, or around the wellbore, will not change much with changes in pore pressure, as the contribution of the fluid pressure is small. Three natural fractures from the Austin chalk were tested, but two of the fractures were very tight and probably do not contribute much to production. The third sample was highly conductive and showed some stress sensitivity with a factor of three reduction in conductivity over a net stress increase of 3000 psi. Natural fractures also showed a propensity for permanent damage when net stressed exceeded about 3000 psi. This damage was irreversible and significantly affected conductivity. {alpha} was difficult to determine and most tests were inconclusive, although the results from one sample suggested that {alpha} was near unity.

The electronic components business within the Nuclear Weapons Complex spans organizational and Department of Energy contractor boundaries. An assessment of the current processes indicates a need for fundamentally changing the way electronic components are developed, procured, and manufactured. A model is provided based on a virtual enterprise that recognizes distinctive competencies within the Nuclear Weapons Complex and at the vendors. The model incorporates changes that reduce component delivery cycle time and improve cost effectiveness while delivering components of the appropriate quality.

MELTER is an analysis of cargo responses inside a fire-threatened Safe-Secure Trailer (SST) developed for the Defense Program Transportation Risk Assessment (DPTRA). Many simplifying assumptions are required to make the subject problem tractable. MELTER incorporates modeling which balances the competing requirements of execution speed, generality, completeness of essential physics, and robustness. Input parameters affecting the analysis include those defining the fire scenario, those defining the cargo loaded in the SST, and those defining properties of the SST. For a specified fire, SST, and cargo geometry MELTER predicts the critical fire duration that will lead to a failure. The principal features of the analysis include: (a) Geometric considerations to interpret fire-scenario descriptors in terms of a thermal radiation boundary condition, (b) a simple model of the SST`s wall combining the diffusion model for radiation through optically-thick media with an endothermic reaction front to describe the charring of dimensional, rigid foam in the SST wall, (c) a transient radiation enclosure model, (d) a one-dimensional, spherical idealization of the shipped cargos providing modularity so that cargos of interest can be inserted into the model, and (e) associated numerical methods to integrate coupled, differential equations and find roots.

Fission-fragment pumped 1.73 {mu}m atomic xenon laser output was measured without changing the laser gas mixture before each reactor pulse. For a Ar/Xe gas mixture at 260 Torr and 0.3 percent xenon, no degradation in laser output was noted for five reactor pulses.

One mechanism for the penetration of lightning energy into the interior of a weapon is by current diffusion through the exterior metal case. Tests were conducted in which simulated lightning currents were driven over the exteriors of similar aluminum and ferrous steel cylinders of 0.125-in wall thickness. Under conditions in which the test currents were driven asymmetrically over the exteriors of the cylinders, voltages were measured between various test points in the interior as functions of the amplitude and duration of the applied current. The maximum recorded open-circuit voltage, which occurred in the steel cylinder, was 1.7 V. On separate shots, currents flowing on a low impedance shorting conductor between the same set of test points were also measured, yielding a maximum current of 630 A, again occurring across the interior of the steel cylinder. Under symmetrical exterior drive current conditions, a maximum end-to-end internal voltage of 4.1 V was obtained, also in the steel cylinder, with a corresponding current of 480 A measured on a coaxial conductor connected between the two end plates of the cylinder. Data were acquired over a range of input current amplitudes between about 40 and 100 kA. These data provide the experimental basis for validating models that can subsequently be applied to real weapons and other objects of interest.

Apparent malfunctions of two Trajectory Sensing Signal Generators (TSSGs) were observed during B61-3/4/10 trajectory arming tests at the Pantex Weapons Evaluation Test Laboratory (WETL). On two subsequent occasions, the TSSG used in the B83 bomb developed single-channel failures during tests at WETL. It was concluded that the failures were related to the electrostatic discharge (ESD) hazard associated with the use of a Thermotron{reg_sign} liquid carbon dioxide (CO{sub 2}) refrigeration system. It was demonstrated that during temperature conditioning, the case of the TSSG can acquire a substantial electrostatic charge as a result of triboelectric processes. A series of tests was performed to identify the charging mechanisms associated with liquid CO{sub 2} refrigeration systems and a quantitative assessment of the ESD hazard was made. The conclusions and recommendations derived in these tests were summarized in a Significant Finding Investigations Closeout. The purpose of this report is to provide formal documentation for, and elaboration on, issues addressed in the Findings.

The electrical effects of lightning penetration of the outer case of a weapon on internal structures, such as a firing set housing, and on samples of a flat, flexline detonator cable have been investigated experimentally. Maximum open-circuit voltages measured on either simulated structures (126 V) or the cable (46 V) located directly behind the point of penetration were well below any level that is foreseen to create a threat to nuclear safety. On the other hand, it was found that once full burnthrough of the barrier occurred, significant fractions of the incident continuing currents coupled to both the simulated internal structure (up to 300 A) or to the cable sample (69 A) when each was electrically connected internally to case ground. No occurrence was observed of the injection of large amplitude currents from return strokes occurring after barrier penetration. Under circumstances in which small volumes of trapped gases exist behind penetration sites, rapid heating of the gas by return strokes occurring after burnthrough has been shown to produced large mechanical impulses to the adjacent surfaces.

The Department of Energy (DOE) has tasked Sandia with conducting a market survey to identify and evaluate pertinent solid state recorders. This report identifies the chosen recorders and explains why they were selected. It details test procedures and provides the results of the evaluation. Our main focus in this evaluation was to determine whether the frame grabber altered signal quality. To determine the effect on the signal, we evaluated specific parameters: sensitivity, resolution, signal-to-noise ratio, and intrascene dynamic range. These factors were evaluated at the input and output of the frame grabber.

A suite of In Situ Permeable Flow Sensors was deployed at the site of the Savannah River Integrated Demonstration to monitor the interaction between the groundwater flow regime and air injected into the saturated subsurface through a horizontal well. One of the goals of the experiment was to determine if a groundwater circulation system was induced by the air injection process. The data suggest that no such circulation system was established, perhaps due to the heterogeneous nature of the sediments through which the injected gas has to travel. The steady state and transient groundwater flow patterns observed suggest that the injected air followed high permeability pathways from the injection well to the water table. The preferential pathways through the essentially horizontal impermeable layers appear to have been created by drilling activities at the site.

As part of Sandia`s Corporate Diversity Program, a Diversity Action Team was assembled to study the impact of diversity on teamwork. We reviewed the available literature on successful teaming, both with homogeneous (more alike than different) and heterogeneous teams. Although many principles and guidelines for successful homogeneous teams also apply to diverse teams, we believe that a document concentrating on diverse teams will be useful both for Sandians and for the outside world.

Abstract not provided.

Sandia National Laboratories, New Mexico (Sandia/NM) has successfully developed and implemented a chargeback system to fund the implementation of Pollution Prevention activities. In the process of establishing this system, many valuable lessons have been learned. This paper describes how the chargeback system currently functions, the benefits and drawbacks of implementing such a system, and recommendations for implementing a chargeback system at other facilities. The initial goals in establishing a chargeback system were to create (1) funding for pollution prevention implementation, including specific pollution prevention projects; and (2) awareness on the part of the line organizations of the quantities and types of waste that they generate, thus providing them with a direct incentive to reduce that waste. The chargeback system inputs waste generation data and then filters and sorts the data to serve two purposes: (1) the operation of the chargeback system; and (2) the detailed waste generation reporting used for assessing processes and identifying pollution prevention opportunities.

The Technology Development and Scoping (TDS) test series was conducted to test and develop instrumentation and procedures for performing steam-driven, high-pressure melt ejection (HPME) experiments at the Surtsey Test Facility to investigate direct containment heating (DCH). Seven experiments, designated TDS-1 through TDS-7, were performed in this test series. These experiments were conducted using similar initial conditions; the primary variable was the initial pressure in the Surtsey vessel. All experiments in this test series were performed with a steam driving gas pressure of {approx_equal} 4 MPa, 80 kg of lumina/iron/chromium thermite melt simulant, an initial hole diameter of 4.8 cm (which ablated to a final hole diameter of {approx_equal} 6 cm), and a 1/10th linear scale model of the Surry reactor cavity. The Surtsey vessel was purged with argon (<0.25 mol% O{sub 2}) to limit the recombination of hydrogen and oxygen, and gas grab samples were taken to measure the amount of hydrogen produced.

There is an instability in certain S.P.H. (Smoothed Particle Hydrodynamics method) material dynamics computations. Evidence from analyses and experiments suggests that the instabilities in S.P.H. are not removable with artificial viscosities. However, the analysis shows that a type of conservative smoothing does remove the instability. Also, numerical experiments, on certain test problems, show that SPHCS, and S.P.H. code with conservative smoothing, compares well in accuracy with computations based on the von Neumann-Richtmyer method.

This report is a summary of the history, design and development, procurement, fabrication, installation and operation of the closures used as containment devices on underground nuclear tests at the Nevada Test Site. It also addresses the closure program mothball and start-up procedures. The Closure Program Document Index and equipment inventories, included as appendices, serve as location directories for future document reference and equipment use.

This report summarizes the progress on the pulsed power approach to inertial confinement fusion. In 1989, the authors achieved a proton focal intensity of 5 TW/cm{sup 2} on PBFA-II in a 15-cm-radius applied magnetic-field (applied-B) ion diode. This is an improvement by a factor of 4 compared to previous PBFA-II experiments. They completed development of the three-dimensional (3-D), electromagnetic, particle-in-cell code QUICKSILVER and obtained the first 3-D simulations of an applied-B ion diode. The simulations, together with analytic theory, suggest that control of electromagnetic instabilities could reduce ion divergence. In experiments using a lithium fluoride source, they delivered 26 kJ of lithium energy to the diode axis. Rutherford-scattered ion diagnostics have been developed and tested using a conical foil located inside the diode. They can now obtain energy density profiles by using range filters and recording ion images on nuclear track recording film. Timing uncertainties in power flow experiments on PBFA-II have been reduced by a factor of 5. They are investigating three plasma opening switches that use magnetic fields to control and confine the injected plasma. These new switches provide better power flow than the standard plasma erosion switch. Advanced pulsed-power fusion drivers will require extraction-geometry applied-B ion diodes. During this reporting period, progress was made in evaluating the generation, transport, and focus of multiple ion beams in an extraction geometry and in assessing the probable damage to a target chamber first wall.

This report was stimulated by some recent investigations of S.P.H. (Smoothed Particle Hydrodynamics method). Solid dynamics computations with S.P.H. show symptoms of instabilities which are not eliminated by artificial viscosities. Both analysis and experiment indicate that conservative smoothing eliminates the instabilities in S.P.H. computations which artificial viscosities cannot. Questions were raised as to whether conservative smoothing might smear solutions more than artificial viscosity. Conservative smoothing, properly used, can produce more accurate solutions than the von Neumann-Richtmyer-Landshoff artificial viscosity which has been the standard for many years. The authors illustrate this using the vNR scheme on a test problem with known exact solution involving a shock collision in an ideal gas. They show that the norms of the errors with conservative smoothing are significantly smaller than the norms of the errors with artificial viscosity.

Prosperity Games are an outgrowth and adaptation of move/countermove and seminar War Games. Prosperity Games are simulations that explore complex issues in a variety of areas including economics, politics, sociology, environment, education and research. These issues can be examined from a variety of perspectives ranging from a global, macroeconomic and geopolitical viewpoint down to the details of customer/supplier/market interactions in specific industries. All Prosperity Games are unique in that both the game format and the player contributions vary from game to game. This report documents the Prosperity Game conducted under the sponsorship of the American Electronics Association in conjunction with the Electronics Subcommittee of the Civilian Industrial Technology Committee of the National Science and Technology Council. Players were drawn from government, national laboratories, and universities, as well as from the electronics industry. The game explored policy changes that could enhance US competitiveness in the manufacturing of consumer electronics. Two teams simulated a presidentially appointed commission comprised of high-level representatives from government, industry, universities and national laboratories. A single team represented the foreign equivalent of this commission, formed to develop counter strategies for any changes in US policies. The deliberations and recommendations of these teams provide valuable insights as to the views of this diverse group of decision makers concerning policy changes, foreign competition, and the development, delivery and commercialization of new technologies.

Inside this issue is a farewell to Testing Technology message from technical advisor, Ruth David. Also included are articles on: Testing the I-40 bridge over the Rio Grande, simulated reactor meltdown studies, an inexpensive monitor for testing integrated circuits, testing of antihelicoptor mines, and quality assurance on aircraft inspection.

This report describes the HP370 component of the Enhanced Graphics System (EGS) used at Tonopah Test Range (TTR). Selected Radar data is fed into the computer systems and the resulting tracking symbols are displayed on high-resolution video monitors in real time. These tracking symbols overlay background maps and are used for monitoring/controlling various flight vehicles. This report discusses both the operational aspects and the internal configuration of the HP370 Workstation portion of the EGS system.

An extensive set of direct-strike lightning tests has been carried out on a set of facsimile assembly joints of the kinds employed in the design of nuclear weapon cases. Taken as a whole, the test hardware included all the conceptual design elements that are embodied, either singly or in combination, in any specific assembly joint incorporated into any stockpiled weapon. During the present testing, the effects of all key design parameters on the voltages developed across the interior of the joints were investigated under a range of lightning stroke current parameter values. Design parameter variations included the types and number of joint fasteners, mechanical preload, surface finish tolerance and coatings, and the material from which the joint assembly was fabricated. Variations of the simulated lightning stroke current included amplitude (30-, 100-, and 200-kA peak), rise time, and decay time. The maximum voltage observed on any of the test joints that incorporated proper metal-to-metal surface contact was 65 V. Typical response values were more on the order of 20 V. In order to assess the effect of the presence of a dielectric coating (either intentional or as a result of corrosion) between the mating surfaces of a joint, a special configuration was tested in which the mating parts of the test assembly were coated with a 1-mil-thick dielectric anodizing layer. First strokes to these test assemblies resulted in very narrow voltage spikes of amplitudes up to 900 V. The durations of these spikes were less than 0.1 {mu}s. However, beyond these initial spikes, the voltages typically had amplitudes of up to 400 V for durations of 3 to 5 {mu}s.

A limited pilot production run on PESC silicon solar cells for use at high concentrations (200 to 400 suns) is summarized. The front contact design of the cells was modified for operation without prismatic covers. The original objective of the contract was to systematically complete a process consolidation phase, in which all the, process improvements developed during the contract would be combined in a pilot production run. This pilot run was going to provide, a basis for estimating cell costs when produced at high throughput. Because of DOE funding limitations, the Photovoltaic Concentrator Initiative is on hold, and Applied Solar`s contract was operated at a low level of effort for most of 1993. The results obtained from the reduced scope pilot run showed the effects of discontinuous process optimization and characterization. However, the run provided valuable insight into the technical areas that can be optimized to achieve the original goals of the contract.

The use of glasses is widespread in making hermetic, insulating seals for many electronic components. Flat panel displays and fiber optic connectors are other products utilizing glass as a structural element. When glass is cooled from sealing temperatures, residual stresses are generated due to mismatches in thermal shrinkage created by the dissimilar material properties of the adjoining materials. Because glass is such a brittle material at room temperature, tensile residual stresses must be kept small to ensure durability and avoid cracking. Although production designs and the required manufacturing process development can be deduced empirically, this is an expensive and time consuming process that does not necessarily lead to an optimal design. Agile manufacturing demands that analyses be used to reduce development costs and schedules by providing insight and guiding the design process through the development cycle. To make these gains, however, viscoelastic models of glass must be available along with the right tool to use them. A viscoelastic model of glass can be used to simulate the stress and volume relaxation that occurs at elevated temperatures as the molecular structure of the glass seeks to equilibrate to the state of the supercooled liquid. The substance of the numerical treatment needed to support the implementation of the model in a 3-D finite element program is presented herein. An accurate second-order, central difference integrator is proposed for the constitutive equations, and numerical solutions are compared to those obtained with other integrators. Inherent convergence problems are reviewed and fixes are described. The resulting algorithms are generally applicable to the broad class of viscoelastic material models. First-order error estimates are used as a basis for developing a scheme for automatic time step controls, and several demonstration problems are presented to illustrate the performance of the methodology.

The necessity to evaluate our participant Quality Assurance (QA) Program for the Yucca Mountain Site Characterization Project (YMP) against the Office of Civilian Radioactive Waste Management (OCRWM) Quality Assurance Requirements and Description (QARD) issued December 1992, presented an opportunity to improve the QA Program. For some time, the SNL YMP technical staff had complained that the QA requirements imposed on their work were cumbersome and inhibited their ability to perform investigations using scientific methods. There was some truth to this, since SNL had over the years developed some procedures with many detailed controls that were far beyond what was required by project QA requirements. This had occurred either as a result of responding to numerous audit findings with a ``make the auditor happy`` attitude or with an attempt to cover every contingency. Procedures affecting scientific work were authored by the technical staff in an effort to provide them with ownership of the process; unfortunately, there were problems. Procedures were inconsistent because of the varied writing styles and differing perceptions of the degree of QA controls required to implement the program. It was extremely difficult to get all of the technical staff to accept the QA program as it was intended. These issues were endemic to the program and resulted in the QARD, the actual requirements, being written by a team of QA professionals. Once new QARD requirements were issued, an opportunity to evaluate the QA Program and to revise it not only to meet the QARD, but also to make it more plausible and meaningful to the technical staff, was presented. The discussion that follows will describe how the program was changed, will present both the positive and negative experiences observed by SNL personnel during the QARD transition, and will provide some recommendations.

One source of uncertainty in calculating radionuclide releases from a potential radioactive-waste at Yucca Mountain, Nevada, is uncertainty in the unsaturated-zone stratigraphy. Uncertainty stratigraphy results from sparse drillhole data; possible variations in stratigraphy are modeled using the geostatistical method of indicator simulation. One-dimensional stratigraphic columns are generated and used for calculations of groundwater flow and radionuclide transport. There are indications of a dependence of release on hydrogeologic-unit thicknesses, but the resulting variation in release is smaller than variations produced by other sources of uncertainty.

The evaluation of the stability of the openings for the Exploratory Studies Facility and a potential repository for high-level nuclear waste at Yucca Mountain, Nevada will require computer codes capable of predicting slip on rock joints resulting from changes in thermal stresses. The geometrical method of analysis of moire fringe analysis was used to evaluate the magnitude and extent of frictional sliding in a layered polycarbonate rock mass model containing a circular hole. Slips were observed in confined zones around the hole and micron resolutions were obtained. Unpredicted and uncontrolled uniform slip of several interfaces in the model were observed giving considerable uncertainty in the boundary conditions of the model, perhaps making detailed comparison with numerical models impossible.

Prediction of the deformation behavior of large engineering structures in jointed rock under a specified loading history requires the extensive use of numerical simulation. For example, the evaluation of the stability of the openings for the Exploratory Studies Facility and a potential repository for high-level nuclear waste at Yucca Mountain, Nevada will require computer codes capable of predicting slip on rock joints resulting from changes in thermal stresses. The testing and ultimate validation of these complex finite element computer codes is an important step in their development before their use as a design tool for an engineering structure or for the study of some other practical problem. While field tests may be ultimately necessary, the authors propose a different and more thorough approach where early tests are done on a bench scale with easily characterized materials and geometries. For these bench-scale tests, the basic approach is to construct a laboratory specimen with a known geometry from an easily characterized material. Digital video imaging combined with the geometric moire fringe method of strain analysis is used to measure and derive the displacements on the sample under load. Here the authors present the method of acquiring and analyzing the moire data and give an analysis of its problems and benefits.

To build a bridge with customers, we balance the linear modeling process with the dynamics of the individuals we serve, who may feel unfamiliar, even confused, with that process. While it is recognized that human factors engineers improve the physical aspect of the workplace, they also work to integrate customers` cognitive styles, feelings, and concerns into the workplace tools. We take customers` feelings into consideration and integrate their expressed needs and concerns into the modeling sessions. After establishing an agreeable, professional relationship, we use a simple, portable CASE tool to reveal the effectiveness of NIAM. This tool, Modeler`s Assistant, is friendly enough to use directly with people who know nothing of NIAM, yet it captures all the information necessary to create complete models. The Modeler`s Assistant succeeds because it organizes the detailed information in an enhanced text format for customer validation. Customer cooperation results from our modeling sessions as they grow comfortable and become enthused about providing information.

Verification measurements may be used to help ensure nuclear criticality safety when burnup credit is applied to spent fuel transport and storage systems. The FORK system measures the passive neutron and gamma-ray emission from spent fuel assemblies while in the storage pool. It was designed at Los Alamos National Laboratory for the International Atomic Energy Agency safeguards program and is well suited to verify burnup and cooling time records at commercial Pressurized Water Reactor (PWR) sites. This report deals with the application of the FORK system to burnup credit operations.

We present two algorithms that use membership and equivalence queries to exactly identify the concepts given by the union of s discretized axis-parallel boxes in d-dimensional discretized Euclidean space where there are n discrete values that each coordinate can have. The first algorithm receives at most sd counterexamples and uses time and membership queries polynomial in s and log n for d any constant. Further, all equivalence queries made can be formulated as the union of O(sd logs) axis-parallel boxes. Next, we introduce a new complexity measure that better captures the complexity of a union of boxes than simply the number of boxes and dimensions. Our new measure, u, is the number of segments in the target polyhedron where a segment is a maximum portion of one of the sides of the polyhedron that lies entirely inside or entirely outside each of the other halfspaces defining the polyhedron. We then present an improvement of our first algorithm that uses time and queries polynomial in u and log n. The hypothesis class used here is decision trees of height at most 2sd, Further we can show that the time and queries used by this algorithm are polynomial in d and log n for s any constant thus generalizing the exact learnability of DNF formulas with a constant number of terms. In fact, this single algorithm is efficient for either s or d constant.

This presentation (consisting of vugraphs) first provides the background motivation for Sandia`s effort for the development of improved crystalline silicon solar cells. It then discusses specific results and progress, and concludes with a brief discussion of options for next year.

This report describes the equipment required for initial assembly/maintenance and inspection/resetting of the Fifth Wheel system. It also gives a step-by-step procedure for initial assembly/maintenance inspection and procedures for resetting the system and Eager-Pac installation. The Fifth Wheel system is associated with a tractor-type vehicle used for materials handling.

High Consequence System Surety is an ongoing project at Sandia National Laboratories. This project pulls together a multi- disciplinary team to integrate the elements of surety into an encompassing process. The surety process will be augmented and validated by applying it to an automated system handling a critical nuclear weapon component at the Mason & Hanger Pantex Plant. This paper presents the development to date of an integrated, high consequence surety process.

Heavy Ion Backscattering Spectrometry (HIBS) is a new ion beam analysis tool using heavy, low-energy ions in backscattering mode which can detect very low levels of surface contamination. By taking advantage of the greatly increased scattering cross-section for such ion beams and eliminating unwanted substrate scattering with a thin carbon foil, our research system has achieved a sensitivity ranging from {approximately}5{times}10{sup 10} atoms/cm{sup 2} for Fe to {approximately}1{times}10{sup 9} atoms/cm{sup 2} for Au on Si, without preconcentration. A stand-alone HIBS prototype now under construction in collaboration with SEMATECH is expected to achieve detection limits of {approximately}5{times}10{sup 9} atoms/cm{sup 2} for Fe and {approximately}1{times}10{sup 8} atoms/cm{sup 2} for Au on Si, again without preconcentration. Since HIBS is standardless and has no matrix effects, it will be useful not only as a standalone tool, but also for benchmarking standards for other tools. This conference is testimony to the importance of controlling contamination in microelectronics manufacturing. By the turn of the century, very large scale integrated circuit processing is expected to require contamination levels well below 1{times}10{sup 9} atoms/cm{sup 2} in both starting materials and introduced by processing. One of the most sensitive of existing general-purpose tools is Total reflection X-Ray Fluorescence (TXRF), which can detect {approximately}1{times}10{sup 10} atoms/cm{sup 2} levels of some elements such as Fe and Cu, but for many elements it is limited to 1{times}10{sup 12} atoms/cm{sup 2} or worse. TXRF can achieve a sensitivity of 10{sup 8} atoms/cm{sup 2} through the use of synchrotron radiation or via pre-concentration using Vapor Phase Decomposition. HIBS provides an ion beam analysis capability with the potential for providing similar sensitivity at medium Z and higher sensitivity at larger Z, all without pre-concentration or matrix effects.

We report the results of to separate long-term tests of batteries and charge controllers in small stand-alone PV systems. In these experiments, seven complete systems were tested for two years at each of two locations: Sandia National Laboratories in Albuquerque and the Florida Solar Energy Center in Cape Canaveral, Florida. Each system contained a PV array, flooded-lead-acid battery, a charge controller and a resistive load. Performance of the systems was strongly influenced by the difference in solar irradiance at the two sites, with some batteries at Sandia exceeding manufacturer`s predictions for cycle life. System performance was strongly correlated with regulation reconnect voltage (R{sup 2} correlation coefficient = 0.95) but only weakly correlated with regulation voltage. We will also discuss details of system performance, battery lifetime and battery water consumption.

A model is presented which describes the formation of surface damage ``gouging`` on the rails that guide rocket sleds. An unbalanced sled can randomly cause a very shallow-angle, oblique impact between the sled shoe and the rail. This damage phenomenon has also been observed in high-velocity guns where the projectile is analogous to the moving sled shoe and the gun barrel is analogous to the stationary rail. At sufficiently high velocity, the oblique impact will produce a thin hot layer of soft material on the contact surfaces. Under the action of a normal moving load, the soft layer lends itself to an anti-symmetric deformation and the formation of a ``hump`` in front of the moving load. A gouge is formed when this hump is overrun by the sled shoe. The phenomenon is simulated numerically using the CTH strong shock physics code, and the results are in good agreement with experimental observation.

The objective of this paper is to provide a general overview of hydrologic conditions at the Waste Isolation Pilot Plant (WIPP) by describing several key hydrologic studies that have been carried out as part of the site characterization program over the last 20 years. The paper is composed of three parts: background information about general objectives of the WIPP project; information about the geologic and hydrologic setting of the facility; and information about three aspects of the hydrologic system that are important to understanding the long-term performance of the WIPP facility. For additional detailed information, the reader is referred to the references cited in the text.

Cast blasting can be designed to utilize explosive energy effectively and economically for coal mining operations to remove overburden material. The more overburden removed by explosives, the less blasted material there is left to be transported with mechanical equipment, such as draglines and trucks. In order to optimize the percentage of rock that is cast, a higher powder factor than normal is required plus an initiation technique designed to produce a much greater degree of horizontal muck movement. This paper compares two blast models known as DMC (Distinct Motion Code) and SABREX (Scientific Approach to Breaking Rock with Explosives). DMC, applies discrete spherical elements interacted with the flow of explosive gases and the explicit time integration to track particle motion resulting from a blast. The input to this model includes multi-layer rock properties, and both loading geometry and explosives equation-of-state parameters. It enables the user to have a wide range of control over drill pattern and explosive loading design parameters. SABREX assumes that heave process is controlled by the explosive gases which determines the velocity and time of initial movement of blocks within the burden, and then tracks the motion of the blocks until they come to a rest. In order to reduce computing time, the in-flight collisions of blocks are not considered and the motion of the first row is made to limit the motion of subsequent rows. Although modelling a blast is a complex task, the DMC can perform a blast simulation in 0.5 hours on the SUN SPARCstation 10--41 while the new SABREX 3.5 produces results of a cast blast in ten seconds on a 486-PC computer. Predicted percentage of cast and face velocities from both computer codes compare well with the measured results from a full scale cast blast.

The Mixed Waste Landfill Integrated Demonstration (MWLID) focuses on ``in-situ`` characterization, monitoring, remediation, and containment of landfills in and environments that contain hazardous and mixed waste. The MWLID mission is to assess, demonstrate, and transfer technologies and systems that lead to faster, better, cheaper, and safer cleanup. Most important, the demonstrated technologies will be evaluated against the baseline of conventional technologies. Key goals of the MWLID are routine use of these technologies by Environmental Restoration Groups throughout the DOE complex and commercialization of these technologies to the private sector. The MWLID is demonstrating technologies at hazardous waste landfills located at Sandia National Laboratories and on Kirtland Air Force Base. These landfills have been selected because they are representative of many sites throughout the Southwest and in other and climates.

This paper addresses the issues surrounding the use of NIAM to capture time dependencies in a domain of discourse. The NIAM concepts that support capturing time dependencies are in the event and process portions of the NIAM metamodel, which are the portions most poorly supported by a well-established methodology. This lack of methodological support is a potentially serious handicap in any attempt to apply NIAM to a domain of discourse in which time dependencies are a central issue. However, the capability that NIAM provides for validating and verifying the elementary facts in the domain may reduce the magnitude of the event/process-specification task to a level at which it could be effectively handled even without strong methodological support.

A statistical design of experiments approach has been employed to evaluate the particle removal efficacy of the SC-1/megasonic clean for sub-0.15 {mu}m inorganic particles. The effects of megasonic input power, solution chemistry, bath temperature, and immersion time have been investigated. Immersion time was not observed to be a statistically significant factor. The NH{sub 4}OH/H{sub 2}O{sub 2} ratio was significant, but varying the molar H{sub 2}O{sub 2} concentration had no effect on inorganic particle removal. Substantially diluted chemistries, performed with high megasonic input power and moderate-to-elevated temperatures, was shown to be very effective for small particle removal. Bath composition data show extended lifetimes can be obtained when high purity chemicals are used at moderate (eg., 45{degrees}C) temperature. Transition metal surface concentrations and surface roughness have been measured after dilute SC-1 processing and compared to metallic contamination following traditional SC-1.

I{sub DDQ} testing is mandatory to ensure that low power CMOS ICs meet their design intent. I{sub DDQ} testing is both a design verifier for low quiescent current and a sensitive production test for defects. Quiescent power reduction is particularly important for products such as cardiac pacemakers, laptop computers, and cellular telephones.

Transformers of two different designs; and unencapsulated pot core and an encapsulated toroidal core have been modeled for circuit analysis with circuit simulation tools. We selected MicroSim`s PSPICE and Anology`s SABER as the simulation tools and used experimental BH Loop and network analyzer measurements to generate the needed input data. The models are compared for accuracy and convergence using the circuit simulators. Results are presented which demonstrate the effects on circuit performance from magnetic core losses, eddy currents, and mechanical stress on the magnetic cores.