Many important products and technologies were developed in federal laboratories and were driven initially by national needs and for federal applications. For example, the clean room technology that enhanced the growth of the semiconductor industry was developed at Sandia National Laboratories (SNL) decades ago. Similarly, advances in micro-electro-mechanical-systems (MEMS)--an important set of process technologies vital for product miniaturization--are occurring at SNL. Each of the more than 500 federal laboratories in the US, are sources of R and D that contributes to America's economic vitality, productivity growth and, technological innovation. However, only a fraction of the science and technology available at the federal laboratories is being utilized by industry. Also, federal laboratories have not been applying all the business development processes necessary to work effectively with industry in technology commercialization. This paper addresses important factors that federal laboratories, federal agencies, and industry must address to translate these under utilized technologies into profitable products in the industrial sector.
This paper reports on a recent comparison made between the Air Force Research Laboratory (AFRL) gallium arsenide, optically-triggered switch test configuration and the Sandia National Laboratories (SNL) gallium arsenide, optically-triggered switch test configuration. The purpose of these measurements was to compare the temporal switch jitter times. It is found that the optical trigger laser characteristics are dominant in determining the PCSS jitter.
This contribution provides Sandia's strawballot comments for the Security Version l.l specification, STR-SEC-02.01. Two major comments are addressed here that pertain to potential problems with the use of the Security Association Section digital signature, and potential inconsistencies with the allocation of relative identifiers in the initiating security agent.
The authors have developed a model for the probabilistic behavior of a rechargeable battery acting as the energy storage component in a photovoltaic power supply system. Stochastic and deterministic models are created to simulate the behavior of the system components. The components are the solar resource, the photovoltaic power supply system, the rechargeable battery, and a load. One focus of this research is to model battery state of charge and battery capacity as a function of time. The capacity damage effect that occurs during deep discharge is introduced via a non-positive function of duration and depth of deep discharge events. Because the form of this function is unknown and varies with battery type, the authors model it with an artificial neural network (ANN) whose parameters are to be trained with experimental data. The battery capacity loss model will be described and a numerical example will be presented showing the predicted battery life under different PV system use scenarios.
Over the years that radioactive material (RAM) transportation risk estimates have been calculated using the RADTRAN code, demand for improved geographic resolution of route characteristics, especially density of population neighboring route segments, has led to code improvements that provide more specific route definition. With the advent of geographic information systems (GISs), the achievable resolution of route characteristics is theoretically very high. The authors have compiled population-density data in 1-kilometer increments for routes extending over hundreds of kilometers without impractical expenditures of time. Achievable resolution of analysis is limited, however, by the resolution of available data. U.S. Census data typically have 1-km or better resolution within densely-populated portions of metropolitan areas but census blocks are much larger in rural areas. Geographic resolution of accident-rate data, especially for heavy/combination trucks, are typically tabulated on a statewide basis. These practical realities cause one to ask what level(s) of resolution may be necessary for meaningful risk analysis of transportation actions on a state or interstate scale.
Microfabrication technology has been applied to the development of a miniature, multi-channel gas phase chemical laboratory that provides fast response, small size, and enhanced versatility and chemical discrimination. Each analysis channel includes a sample preconcentrator followed by a gas chromatographic separator and a chemically selective surface acoustic wave detector array to achieve high sensitivity and selectivity. The performance of the components, individually and collectively, is described.
Electrical surges on ac and dc inverter power wiring and diagnostic cables have the potential to shorten the lifetime of power electronics. These surges may be caused by either nearby lightning or capacitor switching transients. This paper contains a description of ongoing surge evaluations of PV power electronics and surge mitigation hardware at Sandia.
This paper discusses the characteristics and needed improvements/enhancements required for the expansion of the grid-tied residential power systems market. The purpose of the paper is to help establish a common understanding, between the technical community and the customers of the technology, of value and costs and what is required in the longer term for reaching the full potential of this application.
This study of adhesional strength and surface analysis of encapsulant and silicon cell samples from a Natural Bridges National Monument (NBNM) Spectrolab module is an attempt to understand from its success. The module was fabricated using polyvinyl butyral (PVB) as an encapsulant. The average adhesional shear strength of the encapsulant at the cell/encapsulant interface in this module was 4.51 MPa or {approximately} 18% lower than that in currently manufactured modules. Typical encapsulant surface composition was as follows: C 75.0 at.% O 23.2 at.%, and Si 1.6 at.%, with Ag {approximately}0.2 at.% and Pb {approximately} 0.5 at.% with some tin respectively over the grid lines and solder bond. Representative silicon cell surface composition was: K 1.4 at.%, C 20.8 at.%, Sn 0.94 at.%, O 15.1 at.%, Na 2.7 at.% and Si 59.0 at.%. The presence of tin detected on the silicon cell surface may be attributed to corrosion of solder bond. The module differs from typical contemporary modules in the use of PVB, metallic mesh type interconnection, and silicon oxide AR coating.
The authors define what they mean by a 30-year module life and the testing protocol that they believe is involved in achieving such a prediction. However, they do not believe that a universal test (or series of tests) will allow for such a prediction to be made. They can test for a lot of things, but they believe it is impossible to provide a 30-year certification for any PV module submitted for test. They explain their belief in this paper.
High photovoltaic (PV) system costs hinder market growth. An approach to studying these costs has been developed using a database containing system, component and maintenance information. This data, which is both technical and non-technical in nature, is to be used to identify trends related to costs. A pilot database exists at this time and work is continuing. The results of this work may be used by the data owners to improve their operations with the goal of sharing non-attributable information with the public and industry at large. The published objectives of the DOE PV program are to accelerate the development of PV as a national and global energy option, as well as ensure US technology and global market leadership. The approach to supporting these objectives is to understand what drives costs in PV applications. This paper and poster session describe work-in-progress in the form of a database that will help identify costs in PV systems. In an effort to address DOE's Five-Year PV Milestones, a program was established in the summer of 1999 to study system costs in three PV applications--solar home lighting, water pumping, and grid-tied systems. This work began with a RFQ requesting data from these types of systems. Creating a partnership with industry and other system organizations such as Non-Government Organizations (NGOs) was the approach chosen to maintain a close time to the systems in the field. Nine participants were selected as partners, who provided data on their systems. Two activities are emphasized in this work. For the first, an iterative approach of developing baseline reliability and costs information with the participants was taken. This effort led to identifying typical components in these systems as well as the specific data (metrics) that would be needed in any analysis used to understand total systems costs.
The newly revised standard, IEEE Std 929-2000, has significant positive implications for those designing inverters for utility-interconnected PV systems and for designers and installers of such systems. A working group of roughly 20 people, including PV systems designers/installers, PV inverter manufacturers and utility engineers spent close to 3 years developing a standard that would be useful and beneficial to all.
This paper describes an approach that was developed to produce structured models that graphically reflect the requirements contained within a text document. The document used in this research is a draft policy document governing business in a research and development environment. In this paper, the authors present a basic understanding of why this approach is needed, the techniques developed, lessons learned during modeling and analysis, and recommendations for future investigation. The modeling method applied on the policy document was developed as an extension to entity relationship (ER) diagrams, which built in some structural information typically associated with object-oriented techniques. This approach afforded some structure as an analysis tool, while remaining flexible enough to be used with the text document. It provided a visual representation that allowed further analysis and layering of the model to be done.
Engineers have learned to design and build big projects, which certainly describes the WIPP project, but also includes defense projects, highway networks, space exploration, the Internet, etc., through what has been called a messily complex embracing of contradictions. When something massive and complicated has to be built these days, it leads to a protracted political process in which every special interest makes a stand, lobbyists exert what influence they can, lawmakers bicker, contractors change things, Congress struggles with costs, environmentalists hold things up--and this is good. It may seem amazing that anything gets done, but when it does, everyone has had their say. It's an intensely democratic, even if expensive and time-consuming, process. The corporate historian of Sandia National Laboratories presents a unique background of the WIPP project and Sandia's part in it.
As computational needs for structural finite element analysis increase, a robust implicit structural dynamics code is needed which can handle millions of degrees of freedom in the model and produce results with quick turn around time. A parallel code is needed to avoid limitations of serial platforms. Salinas is an implicit structural dynamics code specifically designed for massively parallel platforms. It computes the structural response of very large complex structures and provides solutions faster than any existing serial machine. This paper gives a current status of Salinas and uses demonstration problems to show Salinas' performance.
A completely foundry compatible chip-scale package for surface micromachines has been successfully demonstrated. A pyrex (Corning 7740) glass cover is placed over the released surface micromachined die and anodically bonded to a planarized polysilicon bonding ring. Electrical feedthroughs for the surface micromachine pass underneath the polysilicon sealing ring. The package has been found to be hermetic with a leak rate of less than 5 x 10{sup {minus}8} atm cm{sup {minus}3}/s. This technology has applications in the areas of hermetic encapsulation and wafer level release and die separation.
Resonance Tunneling Diodes (RTDs) are devices that can demonstrate very high-speed operation. Typically they have been fabricated using epitaxial techniques and materials not consistent with standard commercial integrated circuits. The authors report here the first demonstration of SiO{sub 2}-Si-SiO{sub 2} RTDs. These new structures were fabricated using novel combinations of silicon integrated circuit processes.
The authors have investigated the formation of 2-D and 3-D superlattices of Au nanoclusters synthesized in nonionic inverse micelles, and capped with alkyl thiol ligands, with alkane chains ranging from C{sub 6} to C1{sub 18}. The thiols are found to play a significant role in the ripening of these nanoclusters, and in the formation of superlattices. Image processing techniques were developed to reliably extract from transmission electron micrographs (TEMs) the particle size distribution, and information about the superlattice domains and their boundaries. The latter permits one to compute the intradomain vector pair correlation function, from which one can accurately determine the lattice spacing and the coherent domain size. From these data the gap between the particles in the coherent domains can be determined as a function of the thiol chain length. It is found that as the thiol chain length increases, the nanoclusters become more polydisperse and larger, and the gaps between particles within superlattice domains increases. Annealing studies at elevated temperatures confirm nanocluster ripening. Finally, the effect of the particle gaps on physical properties is illustrated by computing the effective dielectric constant, and it is shown that the gap size now accessible in superlattices is rather large for dielectric applications.
In PKM Machines, the Cartesian position and orientation of the tool point carried on the platform is obtained from a kinematic model of the particular machine. Accurate positioning of these machines relies on the accurate knowledge of the parameters of the kinematic model unique to the particular machine. The parameters in the kinematic model include the spatial locations of the joint centers on the machine base and moving platform, the initial strut lengths, and the strut displacements. The strut displacements are readily obtained from sensors on the machine. However, the remaining kinematic parameters (joint center locations, and initial strut lengths) are difficult to determine when these machines are in their fully assembled state. The size and complexity of these machines generally makes it difficult and somewhat undesirable to determine the remaining kinematic parameters by direct inspection such as in a coordinate measuring machine. In order for PKMs to be useful for precision positioning applications, techniques must be developed to quickly calibrate the machine by determining the kinematic parameters without disassembly of the machine. A number of authors have reported techniques for calibration of PKMs (Soons, Masory, Zhuang et. al., Ropponen). In two other papers, the authors have reported on work recently completed by the University of Florida and Sandia National Laboratories on calibration of PKMs, which describes a new technique to sequentially determine the kinematic parameters of an assembled parallel kinematic device. The technique described is intended to be used with a spatial coordinate measuring device such as a portable articulated CMM measuring arm (Romer, Faro, etc.), a Laser Ball Bar (LBB), or a laser tracker (SMX< API, etc.). The material to be presented is as follows: (1) methods to identify the kinematic parameters of 6--6 variant Stewart platform manipulators including joint center locations relative to the workable and spindle nose, and initial strut lengths, (2) and example of the application of the method, and (3) results from the application of the technique.
A new sample preparation procedure has been developed for digestion of soil samples for uranium analysis. The technique employs a microwave oven digestion system to digest the sample and to prepare it for separation chemistry and analysis. The method significantly reduces the volume of acids used, eliminates a large fraction of acid vapor emissions, and speeds up the analysis time. The samples are analyzed by four separate techniques: Gamma Spectrometry, Alpha Spectroscopy using the open digestion method, Kinetic Phosphorescence Analysis (KPA) using open digestion, and KPA by Microwave digestion technique. The results for various analytical methods are compared and used to confirm the validity of the new procedure. The details of the preparation technique along with its benefits are discussed.
Disilaoxacyclopentanes have proven to be excellent precursors to sol-gel type materials. These materials have shown promise as precursors for encapsulation and microelectronics applications. The polymers are highly crosslinked and are structurally similar to traditional sol-gels, but unlike typical sol-gels they are prepared without the use of solvents and water, they have low VOC's and show little shrinkage during processing.
A lattice-Monte Carlo approach was developed to simulate ferroelectric domain behavior. The model utilizes a Hamiltonian for the total energy that includes electrostatic terms (involving dipole-dipole interactions, local polarization gradients, and applied electric field), and elastic strain energy. The contributions of these energy components to the domain structure and to the overall applied field response of the system were examined. In general, the model exhibited domain structure characteristics consistent with those observed in a tetragonally distorted ferroelectric. Good qualitative agreement between the appearance of simulated electrical hysteresis loops and those characteristic of real ferroelectric materials was found.
In a previous study of tangent site chains near a surface, the inhomogeneous density profiles were found through Density Functional theory. In the current study, the surface tensions of these systems are found from the results of the previous study through a thermodynamic integration. The calculated surface tensions are then compared to those found directly through computer simulation. Both the surface tension and surface excess for polymeric systems are shown to qualitatively differ from those of atomic systems, although certain similarities are seen at high densities.
This paper characterizes the homotopy properties and the global topology of the space of positions of vehicles which are constrained to travel without intersecting on a network of paths. The space is determined by the number of vehicles and the network. Paths in the space correspond to simultaneous non-intersecting motions of all vehicles. The authors therefore focus on computing the homotopy type of the space, and show how to do so in the general case. Understanding the homotopy type of the space is the central issue in controlling the vehicles, as it gives a complete description of the distinct ways that vehicles may move safely on the network. The authors exhibit graphs, products of graphs, and amalgamations of products of graphs that are homotopy equivalent to the full configuration space, and are far simpler than might be expected. The results indicate how a control system for such a network of vehicles (such as a fleet of automatically guided vehicles guided by wires buried in a factory floor) may be implemented.