Publications

This paper describes a product realization process developed at Sandia National Laboratories by the A-PRIMED project that integrates many of the key components of ``agile manufacturing`` into a complete, step-by-step, design-to-production process. For three separate product realization efforts, each geared to a different set of requirements, A-PRIMED demonstrated product realization of a custom device in less than a month. A-PRIMED used a discriminator (a precision electro-mechanical device) as the demonstration device, but the process is readily adaptable to other electro-mechanical products. The process begins with a qualified design parameter space. From that point, the product realization process encompasses all facets of requirements development, analysis and testing, design, manufacturing, robotic assembly and quality assurance, as well as product data management and concurrent engineering. In developing the product realization process, A-PRIMED employed an iterative approach whereby after each of three builds, the process was reviewed and refinements made on the basis of lessons learned. This paper describes the integration of project functions and product realization technologies, with references to reports detailing specific facets of the overall process. The process described herein represents the outcome of an empirically-based process development effort that on repeated iterations, was proven successful.

This report outlines the estimates that were made in 1992 of the potential load requirements for Boquillas del Carmen, a small Mexican village on the northern border of the state of Coahuila, Mexico near Big Bend National Park in southern Texas. The study was made to help determine the possibility that village might be electrified by solar or wind energy. Various estimates of are given of the potential load based on estimates ranging from basic use of lights, radio, television, and small household appliances to microwave ovens, refrigerators, and direct evaporative coolers. The low-energy consumption case was estimated to be at 23.0 kWh/month per residence per month, and the high-energy consumption case (with cooling) was 140.7 kWh/month per residence. On average, the typical residence is occupied by five individuals.

Large, three-dimensional enclosure radiation beat transfer problems place a heavy demand on computing resources such as computational cycles, memory requirements, disk I/O, and disk space usage. This is primarily due to the computational and memory requirements associated with the view factor calculation and subsequent access of the view factor matrix during solution of the radiosity matrix equation. This is a fundamental problem that constrains Sandia`s current modeling capabilities. Reducing the computational and memory requirements for calculating and manipulating view factors would enable an analyst to increase the level of detail at which a body could be modeled and would have a major impact on many programs at Sandia such as weapon and transportation safety programs, component survivability programs, energy programs, and material processing programs. CHAPARRAL is a library package written to address these problems and is specifically tailored towards the efficient solution of extremely large three-dimensional enclosure radiation heat transfer problems.

Evaluation of groundwater travel time (GWTT) is required as part of the investigation of the suitability of Yucca Mountain as a potential high-level nuclear-waste repository site. The Nuclear Regulatory Commission`s GWTT regulation is considered to be a measure of the intrinsic ability of the site to contain radionuclide releases from the repository. The work reported here is the first step in a program to provide an estimate of GWTT at the Yucca Mountain site in support of the DOE`s Technical Site Suitability and as a component of a license application. Preliminary estimation of the GWTT distribution in the unsaturated zone was accomplished using a numerical model of the physical processes of groundwater flow in the fractured, porous medium of the bedrock. Based on prior investigations of groundwater flow at the site, fractures are thought to provide the fastest paths for groundwater flow; conditions that lead to flow in fractures were investigated and simulated. Uncertainty in the geologic interpretation of Yucca Mountain was incorporated through the use of geostatistical simulations, while variability of hydrogeologic parameters within each unit was accounted for by the random sampling of parameter probability density functions. The composite-porosity formulation of groundwater flow was employed to simulate flow in both the matrix and fracture domains. In this conceptualization, the occurrence of locally saturated conditions within the unsaturated zone is responsible for the initiation of fast-path flow through fractures. The results of the GWTT-94 study show that heterogeneity in the hydraulic properties of the model domain is an important factor in simulating local regions of high groundwater saturation. Capillary-pressure conditions at the surface boundary influence the extent of the local saturation simulated.

Mission-directed public-sector research facilities are experiencing increasingly severe budget environments while seeing expanding missions and responsibilities. In an effort to identify research leveraging methodologies an information search was conducted in conjunction with some efforts to find the proper links to systems engineering fundamentals. The result is an initial model for use in a preconcept/phase-1 engineering design organization, with a goal of improving the organizations performance.

Systems Engineering is an interdisciplinary process that ensures that the customers` needs are satisfied throughout a system`s entire life cycle. This process includes: understanding customer needs; stating the problem; specifying requirements; defining performance and cost measures, prescribing tests, validating requirements, conducting design reviews, exploring alternative concepts, sensitivity analyses, functional decomposition, system design, designing and managing interfaces, system integration, total system test, configuration management, risk management, reliability analysis; total quality management; project management; and documentation. Material for this paper was gathered from senior Systems Engineers at Sandia National Laboratories.

The characterization of systems engineering as a discipline, process, procedure or a set of heuristics will have an impact on the implementation strategy, the training methodology, and operational environment. The systems engineering upgrade activities in the New Mexico Weapons Development Center and a search of systems engineering related information provides evidence of a degree of ambiguity in this characterization of systems engineering. A case is made in this article for systems engineering being the engineering discipline applied to the science of complexity. Implications of this characterization and some generic issues are delineated with the goal of providing an enterprise with a starting point for developing its business environment.

Inside Sandia, published every other month, presents technological advances made at Sandia National Laboratories. The articles in IS will cover a wide range of technologies that have been developed at Sandia. Some of the areas that will receive a good deal of attention in these pages include information sciences, manufacturing and robotics, environmental science, energy research, transportation technology, and biomedical engineering. All of this work is done to further Sandia National Laboratories` missions in defense, energy, and environmental research, and technology transfer.

No abstract available.

The Department of Energy is conducting an ongoing investigation of the consequences of taking fuel burnup into account in the design of spent fuel transportation packages. A series of experiments, collectively called the Spent Fuel Safety Experiment (SFSX), has been devised to provide integral benchmarks for testing computer-generated predictions of spent fuel behavior. A set of experiments is planned in which sections of unirradiated fuel rods are interchanged with similar sections of spent PWR fuel rods in a critical assembly. By determining the critical size of the arrays, one can obtain benchmark data for comparison with criticality safety calculations. The SFSX provides a direct measurement of the reactivity effects of spent PWR fuel using a well-characterized, spent fuel sample. The SFSX also provides an experimental measurement of the end-effect, i.e., the reactivity effect of the variation of the burnup profile at the ends of PWR fuel rods. The design of the SFSX is optimized to yield accurate benchmark measurements of the effects of interest, well above experimental uncertainties.

Hypervelocity tests of spacecraft optical sensors were conducted to determine if the optical signature from an impact inside the optical sensor sunshade resembled signals that have been observed on-orbit. Impact tests were conducted in darkness and with the ejected debris illuminated. The tests were conducted at the Johnson Space Center Hypervelocity Impact Test Facility. The projectile masses and velocities that may be obtained at the facility are most representative of the hypervelocity particles thought to be responsible for a group of anomalous optical sensors responses that have been observed on-orbit. The projectiles are a few micrograms, slightly more massive than the microgram particles thought to be responsible for the signal source. The test velocities were typically 7.3 km/s, which are somewhat slower than typical space particles.

Successful robot systems must employ actions that are robust in the face of task uncertainty. Toward this end, Lozano-Perez, Mason, and Taylor developed a model of manipulation tasks that explicitly considers task uncertainty. In this paper we study the utility of this model applied to real-world tasks. We report the results of two experiments that highlight the strengths and weaknesses of the LMT approach. The first experiment showed that the LMT formalism can successfully plan solutions for a complex real-world task. The second experiment showed a task that the formalism is fundamentally incapable of solving.

Mass transport properties are important in polycrystalline materials used as protective films. Traditionally, such properties have been studied by examining model polycrystalline structures, such as a regular array of straight grain boundaries. However, these models do not account for a number of features of real grain ensembles, including the grain size distribution and the topological aspects of grain boundaries. In this study, a finite difference scheme is developed to study transient and steady-state mass transport through realistic two-dimensional polycrystalline microstructures. Effects of microstructural parameters such as average grain size and grain boundary topology are examined, as are effects due to limits of the model.

This paper presents some design considerations for small, flyback transformers used to charge energy storage capacitors to 0.1 to 5 KV from a low voltage DC source.

A numerical model for simulating the transient nonlinear behavior of 2-D viscous sloshing flows in rectangular containers subjected to arbitrary horizontal accelerations is presented. The potential-flow formulation uses Rayleigh damping to approximate the effects of viscosity, and Lagrangian node movement is used to accommodate violent sloshing motions. A boundary element approach is used to efficiently handle the time-changing fluid geometry. Additionally, a corrected equation is presented for the constraint condition relating normal and tangential derivatives of the velocity potential where the fluid free surface meets the rigid container wall. The numerical model appears to be more accurate than previous sloshing models, as determined by comparison against exact analytic solutions and results of previously published models.

The criminal justice projects at SNL include three projects for the National Institute of Justice (smart gun, restraining foam, aqueous foam, corrections perimeter), a Southwest Border study, and one involving corrections agencies. It is concluded that the national technologies developed to protect nuclear and other high value assets have enormous potential for application to crime and personal safety; the difficulty lies in simplifying the technology transfer and making the new systems affordable.

An overview of emissive display technologies is presented. Display types briefly described include: cathode ray tubes (CRTs), field emission displays (FEDs), electroluminescent displays (ELDs), and plasma display panels (PDPs). The critical role of phosphors in further development of the latter three flat panel emissive display technologies is outlined. The need for stable, efficient red, green, and blue phosphors for RGB fall color displays is emphasized.

Verification, calibration, and validation (VCV) of Computational Fluid Dynamics (CFD) codes is an essential element of the code development process. The exact manner in which code VCV activities are planned and conducted, however, is critically important. It is suggested that the way in which code validation, in particular, is often conducted--by comparison to published experimental data obtained for other purposes--is in general difficult and unsatisfactory, and that a different approach is required. This paper describes a proposed methodology for CFD code VCV that meets the technical requirements and is philosophically consistent with code development needs. The proposed methodology stresses teamwork and cooperation between code developers and experimentalists throughout the VCV process, and takes advantage of certain synergisms between CFD and experiment. A novel approach to uncertainty analysis is described which can both distinguish between and quantify various types of experimental error, and whose attributes are used to help define an appropriate experimental design for code VCV experiments. The methodology is demonstrated with an example of laminar, hypersonic, near perfect gas, 3-dimensional flow over a sliced sphere/cone of varying geometrical complexity.

The use of the NII (National Information Infrastructure) is growing rapidly in the number of users and in the areas in which it is being applied. Sandia is using, the NII to leverage the use of geographically distributed mechatronic (electromechanical) assets. This paper discusses the availability of networks, new challenges for robotics technology, and how the use of networks is helping to meet these challenges. A brief overview of the NII is provided, followed by a listing of ``needs`` within the intelligent systems community. An approach is then given for meeting, these needs and, finally, implementation, examples, and future research directions are discussed.

Recent worldwide events have shown that explosives are the weapon of choice of terrorists in a variety of situations. For this reason, the need exists to develop a walk-through explosives detector that can be used at airports, government buildings, and other sites requiring both high security and the rapid screening of large numbers of people. In this paper, we discuss on-going efforts at Sandia to develop a walk-through explosives detection portal for the Federal Aviation Administration (FAA). We present a brief overview of detectors and detection methods currently utilized in this field, and discuss the special challenges associated with the development of portal detectors. Preliminary results obtained with the portal system at Sandia indicate that the overall portal concept is viable for the detection of contraband high explosives.

The Long Range Video Observation Post (LRVOP) Project is a cooperative effort between the US and a Middle Eastern country to develop an improved version of their current video observation post. This project is part of a larger effort to cooperatively develop anti-terrorist technology. This particular equipment is required to facilitate the recording and identification of humans at a range of 1000 meters in day-light and 500 meters at night. The project objective was to take advantage of recent advances in camera technology, recorders, and image processing to provide an significant increase in performance with only a minimum increase in size, weight, and cost. The goal of the project was to convert the users general needs and desires into specific requirements that could be bid on by several companies. This paper covers the specific performance requirements, generally describe the components that might be used, and concentrate on describing the more difficult issues and technical challenges.

In the past many DOE and DoD facilities involved in handling nuclear material realized a need to enhance the safely and security for movement of sensitive materials within their facility, or ``intra-site``. There have been prior efforts to improve on-site transportation; however, there remains a requirement for enhanced on-site transportation at a number of facilities. The requirements for on-site transportation are driven by security, safety, and operational concerns. The Intra-site Secure Transport Vehicle (ISTV) was designed to address these concerns specifically for DOE site applications with a standardized vehicle design. This paper briefly reviews the ISTV design features providing significant enhancement of onsite transportation safety and security, and also describes the test and evaluation activities either complete of underway to validate the vehicle design and operation.

Thermal optimization procedures have been applied to determine the worst-case heating boundary conditions that a safety device can be credibly subjected to. There are many interesting aspects of this work in the areas of thermal transport, optimization, discrete modeling, and computing. The forward problem involves transient simulations with a nonlinear 3-D finite element model solving a coupled conduction/radiation problem. Coupling to the optimizer requires that boundary conditions in the thermal model be parameterized in terms of the optimization variables. The optimization is carried out over a diverse multi-dimensional parameter space where the forward evaluations are computationally expensive and of unknown duration a priori. The optimization problem is complicated by numerical artifacts resulting from discrete approximation and finite computer precision, as well as theoretical difficulties associated with navigating to a global minimum on a nonconvex objective function having a fold and several local minima. In this paper we report on the solution of the optimization problem, discuss implications of some of the features of this problem on selection of a suitable and efficient optimization algorithm, and share lessons learned, fixes implemented, and research issues identified along the way.

Single-walled carbon nanotube models have been constructed by insertion of 10-carbon bracelets into C{sub 70} to form C{sub 90} and C{sub 120}. Semiempirical heats of vicinal hydrogenation along the sides of the tubes are {approximately}40 kcal/mol more endothermic (less stable) than addition to the endcaps. Based on the similarity of the endcaps to C{sub 60}, hydrogenation of nanotubes is estimated to be approximately thermoneutral; therefore, only relatively high energy dienes or other species are likely to yield stable addended products.

A mechanical isolator has been developed for a piezoresistive accelerometer. The purpose of the isolator is to mitigate high frequency shocks before they reach the accelerometer because the high frequency shocks may cause the accelerometer to resonate. Since the accelerometer is undamped, it often breaks when it resonates. The mechanical isolator was developed in response to impact test requirements for a variety of structures at Sandia National Laboratories. An Extended Technical Assistance Program with the accelerometer manufacturer has resulted in a commercial isolator that will be available to the general public. This mechanical isolator has ten times the bandwidth of any other commercial isolator and has acceptable frequency domain performance from DC to 10 kHz ({plus_minus} 10%) over a temperature range of -65{degrees}F to +185{degrees}F as demonstrated in this paper.