Sealing methods and materials currently used in salt and potash industries were surveyed to determine if systems analogous to the shaft seal design proposed for the Waste Isolation Pilot Plant (WIPP) exist. Emphasis was first given to concrete and then expanded to include other materials. Representative case studies could provide useful design, construction, and performance information for development of the WIPP shaft seal system design. This report contains a summary of engineering and construction details of various sealing methods used by mining industries for bulkheads and shaft liners. Industrial experience, as determined from site visits and literature reviews, provides few examples of bulkheads built in salt and potash mines for control of water. Sealing experiences representing site-specific conditions often have little engineering design to back up the methods employed and even less quantitative evaluation of seal performance. Cases examined include successes and failures, and both contribute to a database of experiences. Mass salt-saturated concrete placement under ground was accomplished under several varied conditions. Information derived from this database has been used to assess the performance of concrete as a seal material. Concrete appears to be a robust material with successes in several case studies. 42 refs.
This report presents the results of instrumentation measurements and observations made during construction of the North Ramp Starter Tunnel (NRST) of the Exploratory Studies Facility (ESF). The information in this report was developed as part of the Design Verification Study, Section 8.3.1.15.1.8 of the Yucca Mountain Site Characterization Plan (DOE 1988). The ESF is being constructed by the US Department of Energy (DOE) to evaluate the feasibility of locating a potential high-level nuclear waste repository on lands within and adjacent to the Nevada Test Site (NTS), Nye County, Nevada. The Design Verification Studies are performed to collect information during construction of the ESF that will be useful for design and construction of the potential repository. Four experiments make up the Design Verification Study: Evaluation of Mining Methods, Monitoring Drift Stability, Monitoring of Ground Support Systems, and The Air Quality and Ventilation Experiment. This report describes Sandia National Laboratories` (SNL) efforts in the first three of these experiments in the NRST.
This international directory of more than 500 photovoltaic-related manufacturers is intended to guide potential users of photovoltaics to sources for systems and their components. Two indexes help the user to locate firms and materials. A glossary describes equipment and terminology commonly used in the photovoltaic industry.
Sandia National Laboratories and Industrial Solar Technology are cost-sharing development of advanced parabolic trough technology. As part of this effort, several configurations of an IST solar collector were tested to determine the collector efficiency and thermal losses with black chrome and black nickel receiver selective coatings, combined with aluminized film and silver film reflectors, using standard Pyrex{reg_sign} and anti-reflective coated Pyrex{reg_sign} glass receiver envelopes. The development effort has been successful, producing an advanced collector with 77% optical efficiency, using silver-film reflectors, a black nickel receiver coating, and a solgel anti-reflective glass receiver envelope. For each receiver configuration, performance equations were empirically derived relating collector efficiency and thermal losses to the operating temperature. Finally, equations were derived showing collector performance as a function of input insolation value, incident angle, and operating temperature.
Solar Kinetics, Inc., has been developing a point-focus concentrating photovoltaic module and tracker system under contract to Sandia National Laboratories. The primary focus of the contract was to achieve a module design that was manufacturable and passed Sandia`s environmental testing. Nine modules of two variations were assembled, tested, and characterized in Phase 1, and results of these tests were promising, with module efficiency approaching the theoretical limit achievable with the components used. The module efficiency was 11.9% at a solar irradiance of 850 W/sq m and an extrapolated cell temperature of 25 C. Improvements in module performance are anticipated as cell efficiencies meet their expectations. A 2-kW tracker and controller accommodating 20 modules was designed, built, installed, and operated at Solar Kinetics` test site. The drive used many commercially available components in an innovative arrangement to reduce cost and increase reliability. Backlash and bearing play were controlled by use of preloaded, low slip-stick, synthetic slide bearings. The controller design used a standard industrial programmable logic controller to perform ephemeris calculations, operate the actuators, and monitor encoders.
The objective of the workshop was to promote discussions between experts and research managers on developing approaches for assessing the impact of DOE`s basic energy research upon the energy mission, applied research, technology transfer, the economy, and society. The purpose of this impact assessment is to demonstrate results and improve ER research programs in this era when basic research is expected to meet changing national economic and social goals. The questions addressed were: (1) By what criteria and metrics does Energy Research measure performance and evaluate its impact on the DOE mission and society while maintaining an environment that fosters basic research? (2) What combination of evaluation methods best applies to assessing the performance and impact of OBES basic research? The focus will be upon the following methods: Case studies, User surveys, Citation analysis, TRACES approach, Return on DOE investment (ROI)/Econometrics, and Expert panels. (3) What combination of methods and specific rules of thumb can be applied to capture impacts along the spectrum from basic research to products and societal impacts?
The specific contact resistivity of Cu with ({alpha} + {beta})-Ta, TiN, {alpha}-W, and amorphous-Ta{sub 36}Si{sub 14}N{sub 50} barrier films is measured using a novel four-point-probe approach. Geometrically, the test structures consist of colinear sets of W-plugs to act as current and voltage probes that contact the bottom of a planar Cu/barrier/Cu stack. Underlying Al interconnects link the plugs to the current source and voltmeter. The center-to-center distance of the probes ranges from 3 to 200 {micro}m. Using a relation developed by Vu et al., a contact resistivity of roughly 7 {times} 10{sup {minus}9} {Omega} cm{sup 2} is obtained for all tested barrier/Cu combinations. By reflective-mode small-angle X-ray scattering, the similarity in contact resistivity among the barrier films may be related to interfacial impurities absorbed from the deposition process.
Fine-grained and coarse-grained aluminas containing either equiaxed or elongated grain structures were fabricated from commercial-purity and high-purity alumina powders. Compared to the high-purity aluminas, the commercial-purity aluminas having a coarse grain size and elongated grain structures exhibited significantly more pronounced flaw tolerance and T-curve behavior. T-curve behavior determined from indentation strength tests suggested that only the coarse- grained, elongated-grain alumina had a T-curve sufficient to cause stable crack extension prior to failure, a requirement for any observable improvement in reliability. In the high-purity aluminas as well as the fine-grained commercial-purity aluminas, however, it is likely that little or no stable extension occurs prior failure, suggesting that strength in these materials is dependent on the critical flaw size. Strength tests on polished specimens showed the commercial-purity aluminas had a lower means strength than the high- purity aluminas and the coarse-grained aluminas exhibited a lower mean strength compared to the fine-grained aluminas. An analysis of the mean strength versus grain size revealed that the differences in critical flaw size alone could not account for the differences in mean strength. Instead, a combination of changes in flaw size as well as T-curve behavior were shown to be responsible for the differences in strength and flaw tolerance. T-curve behavior was also found to have a profound influence on the strength variability of alumina. For example, the Weibull modulus for the coarse-grained, commercial- purity alumina was almost twice that of the fine-grained, high-purity material. Tests with indented specimens conclusively demonstrated that improvements in reliability in these materials are not due solely to changes in the critical flaw size distribution but rather a combination of flaw size distribution and T-curve behavior.
The dynamic performance of a 250 Hz resonant plate shock system which simulates pyrotechnic shock environments on micro-electrical components is evaluated. A series of experiments recording strain rate histories and acceleration time histories at several plate locations were conducted. This empirical data is used to compare the analytical results obtained from a finite element based numerical simulation. The comparison revealed a good correlation between experimental and analytical results.
Simulations of soil-heated vapor extraction have been performed to evaluate the NAPL removal performance as a function of borehole vacuum. The possibility of loss of NAPL containment, or NAPL migration into the unheated soil, is also evaluated in the simulations. A practical warning sign indicating migration of NAPL into the unheated zone is discussed.
Hydrogen is readily incorporated into GaN and related alloys during wet and dry etching, chemical vapor deposition of dielectric overlayers, boiling in water and other process steps, in addition to its effects during MOCVD or MOMBE growth. The hydrogen is bound at defects or impurities and passivates their electrical activity. Reactivation occurs at 450-550{degrees}C, but evolution from the crystal requires much higher temperatures ({ge} 800{degrees}C).
We have studied the formation of Fe clusters in inverse micelles. We have characterized the clusters with respect to size with transmission electron microscopy (TEM) and with respect to chemical composition with Mossbauer spectroscopy, electron diffraction, and x-ray photoelectron spectroscopy (XPS). In addition, we have tested these iron based clusters for catalytic activity in a model hydrogenolysis reaction. The formation of ultra-small metal particles is of particular interest in the area of chemical catalysis. The clusters are high surface area, highly dispersed, unsupported materials. In addition, catalytic enhancement due to unique material properties (i.e. quantum size effects) is possible. Metal clusters prepared by a number of techniques have been studied as potential catalysts. Reactant adsorption and the reactivity in various processes depends strongly on particle size. We are studying iron clusters as potential catalysts in hydrogenation reactions, Fischer-Tropsch synthesis, and coal liquefaction.
We have refined the structures for YBa{sub 2}Cu{sub 2.94}Ni{sub 0.06}O{sub y} (2% Ni) and YBa{sub 2}Cu{sub 2.80}Ni{sub 0.20}O{sub y} (6.67% Ni) at y {approximately} 6.95 and y {approximately} 6.5 contents. Oxygen was reduced by two independent methods: quenching from 690{degrees}C and oxygen gettering at 450{degrees}C. Cu-0 bond lengths were calculated based on Rietveld structure refinements for the various samples; they indicate the likely occupancy of Ni in the plane (Cu2) site of the 123 superconductor.
Cathodoluminescent (CL) phosphors with improved low-voltage characteristics are needed for use in emissive flat panel displays. Conventional high-temperature methods for phosphor synthesis yield large polycrystalline grains that must be pulverized prior to screen deposition. Grinding has been implicated in reducing phosphor efficiency by causing surface contamination and defects. Hydrothermal synthesis has been used to improve the quality of ceramic powders by producing fine, well-formed crystallites without grinding. Two green-emitting phosphors, Y{sub 3}Al{sub 5}O{sub 12}:Tb (YAG:Tb) and NaY(WO{sub 4}){sub 2}:Tb, were used to test the effects of hydrothermal. synthesis on grain size and morphology, and on low-voltage CL properties. YAG:Th prepared hydrothermally consisted of submicron crystallites with a typical garnet habit. The CL efficiency of hydrothermally synthesized YAG:Tb (3 lm/W at 800 V) was comparable to that of equivalent YAG:Tb compositions prepared via high-temperature solid state reaction. In comparison, CL intensities of Gd{sub 3}Ga{sub 5}O{sub l2}:Tb were slightly better (3.5 lm/W at 800 V), while those of NaY(WO{sub 4}){sub 2}:Tb were approximately 1/100th that of YAG:Tb. Both CL and photoluminescence data show that the difference in the cathodoluminescence of YAG and NaY(WO{sub 4}){sub 2} can be understood in terms of differences in the mechanism of activation.
Due to their wide band gaps and high dielectric constants, the group III-nitrides have made significant impact on the compound semiconductor community as blue and ultraviolet light emitting diodes (LEDs) and for their potential use in laser structures and high temperature electronics. Processing of these materials, in particular wet and dry etching, has proven to be extremely difficult due to their inert chemical nature. We report electron cyclotron resonance (ECR) etch rates for GaN, InN, AlN, In{sub (x)}Ga{sub (1-x)}Ni and In{sub (x)}Al{sub (1-x)}N as a function of temperature, rf-power, pressure, and microwave power. Etch conditions are characterized for rate, profile, and sidewall and surface morphology. Atomic force microscopy (AFM) is used to quantify RMS roughness of the etched surfaces. We observe consistent trends for the InAlN films where the etch rates increase with increasing concentration of In. The trends are far less consistent for the InGaN with a general decrease in etch rate as the In concentration is increased.
Recent geologic and geophysical investigations within the Albuquerque Basin have shed light on the potentially seismogenic sources that might affect Sandia National Laboratories, New Mexico (SNL/NM), a multi-disciplinary research and engineering facility of the US Department of Energy (DOE). This paper presents a summary of potentially seismogenic sources for SNL/NM, emphasizing those sources within approximately 8 kilometers (km) of the site. Several significant faults of the central Rio Grande rift transect SNL/NM. Although progress has been made on understanding the geometry and interactions of these faults, little is known of the timing of most recent movement or on recurrent intervals for these faults. Therefore, whether particular faults or fault sections have been active during the Holocene or even the late Pleistocene is undocumented. Although the overall subdued surface expression of many of these faults suggests that they have low to moderate slip rates, the proximity of these faults to critical (e.g., nuclear) and non-critical (e.g., high-occupancy, multistory office/light lab) facilities at SNL/NM requires their careful examination for evaluation of potential seismic hazard.
Remote monitoring systems presently operating in facilities in a number of countries around the world are providing valuable information on the installation and operation of such systems. Results indicate they are performing reliably. While the technology for remote monitoring exists today, it may be some time before numerous constraints on implementation can be resolved. However, the constraints should not prevent the designing of systems that can be used for remote monitoring. Selection of the proper technology path for future development should include a flexible approach to front-end detection, data formats, data processing, and other areas. A brief description of two of the existing remote monitoring systems, and some general recommendations for future remote monitoring systems, will be presented.
A number of different disposition alternatives are being considered and include facilities which provide for long-ten-n and interim storage, convert and stabilize fissile materials for other disposition alternatives, immobilize fissile material in glass and/or ceramic material, fabricate fissile material into mixed oxide (MOX) fuel for reactors, use reactor based technologies to convert material into spent fuel, and dispose of fissile material using a number of geologic alternatives. Particular attention will be given to the reactor alternatives which include existing, partially completed, advanced or evolutionary LWRs and CANDU reactors. The various reactor alternatives are all very similar and include processing which converts Pu to a usable form for fuel fabrication, a MOX fuel fab facility located in either the US or in Europe, US LWRs or the CANDU reactors and ultimate disposal of spent fuel in a geologic repository. This paper focuses on how the objectives of reducing security risks and strengthening arms reduction and nonproliferation will be accomplished and the possible impacts of meeting these objectives on facility operations and design. Some of the areas in this paper include: (1) domestic and international safeguards requirements, (2) non-proliferation criteria and measures, (3) the threat, and (4) potential proliferation risks, the impacts on the facilities, and safeguards and security issues unique to the presence of Category 1 or strategic special nuclear material.
A system has been developed by Sandia National Laboratories (SNL) as part of the joint laboratory project with Los Alamos National Laboratory and Argonne National Laboratory-West (ANL-W). The objective is to provide support for Safeguards and Security and Nuclear Materials Control and Accountability within the DOE complex. Since its original design PAMTRAK has been enhanced to include material monitoring, personnel monitoring, and video surveillance. Material monitoring is provided by the WATCH (Wireless Alarm Transmission of Container Handling) subsystem by performing continuous surveillance via constantly monitored Tamper Indicating Devices of all material not directly involved in the fuel manufacturing process. Personnel tracking uses radio frequency and infrared sensors to detect unauthorized access to restricted areas and to enforce constant monitoring of containers or other objects within a ``region of interest`` in a storage vault or other restricted area. Advantages of combining these sensor subsystems include reducing personnel radiation exposure by extending the time between required physical inventory intervals as well as adding robustness to existing security measures. PAMTRAK is being demonstrated as part of the integrated materials monitoring and accounting system in the Fuels and Manufacturing Facility (FMF) located at ANL-W. This paper will describe the technologies employed for installation of the system by SNL, as well as the operational issues involved in using the system at ANL-W.
Long-term repository assessment must consider the processes of (1) gas generation, (2) room closure and expansions due to salt creep, and (3) multiphase (brine and gas) fluid flow, as well as the complex coupling between these three processes. The mechanical creep closure code SANCHO was used to simulate the closure of a single, perfectly sealed disposal room filled with water and backfill. SANCHO uses constitutive models to describe salt creep, waste consolidation, and backfill consolidation, Five different gas-generation rate histories were simulated, differentiated by a rate multiplier, f, which ranged from 0.0 (no gas generation) to 1.0 (expected gas generation under brine-dominated conditions). The results of the SANCHO f-series simulations provide a relationship between gas generation, room closure, and room pressure for a perfectly sealed room. Several methods for coupling this relationship with multiphase fluid flow into and out of a room were examined. Two of the methods are described.
Many studies employ multiple measurement instruments such as human raters, observers, judges, or mechanical gauges to record subject data. It is well known that the consistency of these instruments, commonly called rater reliability, limits the extent to which conclusions should be drawn from the observed data. However, the degree to which rater reliability limits conclusions has traditionally been assessed in only subjective manners. In this paper, a method is developed for objectively quantifying the impact of rate reliability on the statistical analysis of data from a commonly used collection scheme. This method allows the inclusion of a reliability index in statistical power calculations and is an invaluable tool in the planning of experiments.
The Laboratories Services Division of Sandia National Laboratories includes a wide variety of operations such as environmental, safety and health, safeguards and security, facilities, logistics, and sites planning and integration. In the face of declining budgets and increasing requirements, the Management Team needed some tools to assist in negotiating with customers and regulators and in consistently and cost-effectively managing all work performed and/or managed by the Division. The Integrated Services Management System (ISMS) was developed as a series of processes to provide these tools. The Laboratory Integration and Prioritization System (LIPS) was selected as the prioritization methodology for ISMS. The pilot application phase was begun in February 1994 and addressed planning of work and resources for FY95. Extensive training was provided for the Activity Data Sheet (ADS) preparers and the teams which would score each of the activities. After preparation of the ADSs, they were scored by the scoring teams. A division-wide review board reviewed all of the ADSs to ensure consistency of scoring across all of the functional areas. The lessons that were learned from the pilot application were evaluated and improvements incorporated for the FY96 planning and application. The improvements included upgrading the training, providing expert facilitation for scoring boards, modification of the scoring instructions to better represent local situations, and establishing an Validation Board with more authority and accountability to provide quality assurance. The participants in the LIPS process have agreed that no major bases were uncovered, imperfect prioritizations are better than no data, all work packages can be scored and ranked, including core activities, results were objective and quantifiable, and decisions could be made using technically defensible bases.
Customers of Asynchronous Transfer Mode (ATM) services may need a variety of data authenticity and privacy assurances. Cryptographic methods can be used to assure authenticity and privacy, but are hard to scale for implementation at high speed. The incorporation of these methods into computer networks can severely impact functionality, reliability, and performance. To study these trade-offs, a prototype encryptor/decryptor was developed. This effort demonstrated the viability of implementing certain encryption techniques in high speed networks. The research prototype processes ATM cells in a SONET OC-3 payload. This paper describes the functionality, reliability, security, and performance design trade-offs investigated with the prototype.
New developments in dry and wet etching, ohmic contacts and epitaxial growth of Ill-V nitrides are reported. These make possible devices such as microdisk laser structures and GaAs/AlGaAs heterojunction bipolar transistors with improved InN ohmic contacts.
A Multi Spectral Pushbroom Imaging Radiometer (MPIR) has been developed as are relatively inexpensive ({approximately}$IM/copy), well-calibrated,imaging radiometer for aircraft studies of cloud properties. The instrument is designed to fly on an Unmanned Aerospace Vehicle (UAV) platform at altitudes from the surface up to 20 km. MPIR is being developed to support the Unmanned Aerospace Vehicle portion of the Department of Energy`s Atmospheric Radiation Measurements program (ARM/UAV). Radiation-cloud interactions are the dominant uncertainty in the current General Circulation Models used for atmospheric climate studies. Reduction of this uncertainty is a top scientific priority of the US Global Change Research Program and the ARM program. While the DOE`s ARM program measures a num-ber of parameters from the ground-based Clouds and Radiation Testbed sites, it was recognized from the outset that other key parameters are best measured by sustained airborne data taking. These measurements are critical in our understanding of global change issues as well as for improved atmospheric and near space weather forecasting applications.
Aqueous foams are aggregates of bubbles mechanically generated by passing air or other gases through a net, screen, or other porous medium that is wetted by an aqueous solution of surface-active foaming agents (surfactants). Aqueous foams are important in modem fire-fighting technology, as well as for military uses for area denial and riot or crowd control. An aqueous foam is currently being developed and evaluated by Sandia National Laboratories (SNL) as a Less-Than-Lethal Weapon for the National Institute of Justice (NIJ). The purpose of this study is to evaluate the toxicity of the aqueous foam developed for the NIJ and to determine whether there are any significant adverse health effects associated with completely immersing individuals without protective equipment in the foam. The toxicity of the aqueous foam formulation developed for NIJ is determined by evaluating the toxicity of the individual components of the foam. The foam is made from a 2--5% solution of Steol CA-330 surfactant in water generated at expansion ratios ranging from 500:1 to 1000:1. SteoI CA-330 is a 35% ammonium laureth sulfate in water and is produced by Stepan Chemical Company and containing trace amounts (<0.1%) of 1,4-dioxane. The results of this study indicate that Steol CA-330 is a non-toxic, mildly irritating, surfactant that is used extensively in the cosmetics industry for hair care and bath products. Inhalation or dermal exposure to this material in aqueous foam is not expected to produce significant irritation or systemic toxicity to exposed individuals, even after prolonged exposure. The amount of 1,4-dioxane in the surfactant, and subsequently in the foam, is negligible and therefore, the toxicity associated with dioxane exposure is not significant. In general, immersion in similar aqueous foams has not resulted in acute, immediately life-threatening effects, or chronic, long-term, non-reversible effects following exposure.
Deep x-ray lithography based fabrication provides a means to fabricate microactuators with useful output forces. High energy x-ray exposure provides a tool for fabrication of the next generation of precision engineered components. Device characterization, materials science, an metrology continue to pose challenges at this scale.
Sandia`s High Performance Computing Environment requires a hierarchy of resources ranging from desktop, to department, to centralized, and finally to very high-end corporate resources capable of teraflop performance linked via high-capacity Asynchronous Transfer Mode (ATM) networks. The mission of the Scientific Computing Systems Department is to provide the support infrastructure for an integrated corporate scientific computing environment that will meet Sandia`s needs in high-performance and midrange computing, network storage, operational support tools, and systems management. This paper describes current efforts at SNL/NM to expand and modernize centralized computing resources in support of this mission.
High costs and low productivity of manual operations in radiation, chemical, explosive and other hazardous environments have mandated the use of remote means to accomplish many tasks. However, traditional remote operations have proven to have very low productivity when compared with unencumbered humans. To improve the performance of these systems, computer models augmented by sensors, and modular computing environments are being utilized to automate many unstructured hazardous tasks. Establishment of a common structure for developments of modules such as the Generic Intelligent System Controller (GISC), have allowed many independent groups to develop specialized components that can be rapidly integrated into purpose-built robotic systems. The drawback in using this systems is that the equipment investments for such robotic systems can be substantial. In a resource-competitive environment, the ability to readily and reliably reconfigure and reuse assets operated by other industries, universities, research labs, government entities, etc., is proving to be a crucial advantage. Timely and efficient collaboration between entities has become increasingly important as monetary resources of government programs and entire industries expand or contract in response to rapid changes in production demand, dissolution of political barriers, and adoption of stringent environmental and commercial legislation. Sandia National Laboratories (SNL) has developed the System Composer, Virtual Collaborative Environment (VCE) and A{sup primed} technologies described in this paper that demonstrate an environment for flexible and efficient integration, interaction, and information exchange between disparate entities.
High quality crystalline, monodisperse nanometer-size semiconductor clusters were successfully grown using an inverse micellar synthesis process and their optical and structural properties were studied. Among the materials studied were PbS, FeS{sub 2}, MoS{sub 2}, CdS and related compounds. The results demonstrated strong electronic quantum confinement effects and broad tailorability of the bandgaps with decreasing cluster size, features that are important for the potential use of these materials as photocatalysts for solar fuel production and solar detoxification. The highlights of the work are included in an Executive Summary.
The laser characteristics of the 2.65 {mu}m xenon laser transition are reviewed. Measured and extrapolated laser efficiency in nuclear pumped and electron beam pumped system is reported. Previous research has indicated that the reported power efficiency is between 0.1 and 2 percent.
In 1991, under a contract with Sandia for the Concentrator Initiative, the ENTECH team initiated the design and development of a fourth-generation concentrator module. In 1992, Sandia also contracted with ENTECH to develop a new control and drive system for the ENTECH array. This report documents the design and development work performed under both contracts. Manufacturing processes for the new module were developed at the same time under a complementary PVMaT contract with the National Renewable Energy Laboratory. Two 100-kW power plants were deployed in 1995 in Texas using the newly developed fourth-generation concentrator technology, one at the CSW Solar Park near Ft. Davis and one at TUE Energy Park in Dallas. Technology developed under the Sandia contracts has made a successful transition from the laboratory to the production line to the field.
The objective of agile manufacturing is to provide the ability to quickly realize high-quality, highly-customized, in-demand products at a cost commensurate with mass production. More broadly, agility in manufacturing, or any other endeavor, is defined as change-proficiency; the ability to thrive in an environment of unpredictable change. This report discusses the general direction of the agile manufacturing initiative, including research programs at the National Institute of Standards and Technology (NIST), the Department of Energy, and other government agencies, but focuses on agile manufacturing from a statistical perspective. The role of statistics can be important because agile manufacturing requires the collection and communication of process characterization and capability information, much of which will be data-based. The statistical community should initiate collaborative work in this important area.
The authors have used chemical vapor deposition to grow ternary tungsten-based diffusion barriers to determine if they exhibit properties similar to those of sputter-deposited ternaries. A range of different W-B-N compositions in a band of compositions roughly between 20 and 40% W were produced. The deposition temperature was low, 350 C, and the precursors used are well accepted by the industry. Deposition rates are high for a diffusion barrier application. Resistivities range from 200 to 20,000 {micro}{Omega}-cm, the films with the best barrier properties having {approximately}1,000 {micro}{Omega}-cm resistivities. Adhesion to oxides is sufficient to allow these films to be used as the adhesion layer in a tungsten chemical mechanical polishing plug application. The films are x-ray amorphous as-deposited and have crystallization temperatures of up to 900 C. Barrier performance against Cu has been tested using diode test structures. A composition of W{sub .23}B{sub .49}N{sub .28} was able to prevent diode failure up to a 700 C, 30 minute anneal. These materials, deposited by CVD, display properties similar to those deposited by physical deposition techniques.
Oleoresin Capsicum (OC) is an extract of the pepper plant used for centuries as a culinary spice (hot peppers). This material has been identified as a safe and effective Less-Than- Lethal weapon for use by Law enforcement and security professionals against assault. The National Institute of Justice (NIJ) is currently also evaluating its use in conjunction with other Less-Than-Lethal agents such as aqueous foam for use in corrections applications. Therefore, a comprehensive toxicological review of the literature was performed for the National Institute of Justice Less-Than-Lethal Force program to review and update the information available on the toxicity and adverse health effects associated with OC exposure. The results of this evaluation indicate that exposure to OC can result in dermatitis, as well as adverse nasal, pulmonary, and gastrointestinal effects in humans. The primary effects of OC exposure include pain and irritation of the mucous membranes of the eyes, nose, and lining of the mouth. Blistering and rash have been shown to occur after chronic or prolonged dermal exposure. Ingestion of capsicum may cause acute stinging of the lips, tongue, and oral mucosa and may lead to vomiting and diarrhea with large doses. OC vapors may also cause significant pulmonary irritation and prolonged cough. There is no evidence of long term effects associated with an acute exposure to OC, and extensive use as a culinary additive and medicinal ointment has further provided no evidence of long term adverse effects following repeated or prolonged exposure.
Sandia`s STP program is a four-part high-temperature superconductor (HTS) research and development program consisting of efforts in powder synthesis and process development, thallium-based HTS film development, wire and tape fabrication, and HTS motor design. The objective of this work is to develop high-temperature superconducting conductors (wire and tape) capable of meeting requirements for high-power electrical devices of interest to industry. The four research efforts currently underway are: (1) Process research on the material synthesis of high-temperature superconductors, (2) Investigation of the synthesis and processing of thallium-based high-temperature superconducting thick films, (3) Process development and characterization of high-temperature superconducting wire and tape, and (4) Cryogenic design of a high-temperature superconducting motor. This report outlines the research that has been performed during FY94 in each of these four areas. Major areas of research are described, although no attempt has been made to exhaustively include all work performed in each of these areas.
Double layer capacitors with porous carbon electrodes have very low frequency response limits and correspondingly low charge-discharge rates. Impedance measurements of various commercial double layer capacitors and of carbon electrodes prepared from selected precursor materials were found to yield similar, yet subtly different characteristics. Through modeling with the traditional transmission line equivalent circuit for porous electrodes, a resistive layer can be identified, which forms on carbon films during carbonization and survives the activation procedure. A method for determining the power-to-energy ratio of electrochemical capacitors has been developed. These findings help define new ways for optimizing the properties of double layer capacitors.
This document provides information concerning the Integrated Services Management System (ISMS) that was developed for the Laboratories Services Division during the period February 1994 through May 1995. ISMS was developed as a formal method for centralized management of programs within the Division. With minor modifications, this system can be adapted for management of all overhead functions at SNL or for sector level program management. Included in this document are the reasons for the creation of this system as well as the resulting benefits. The ISMS consists of six interlinked processes; Issues Management, Task/Activity Planning, Work Decision, Commitment Management, Process/Project Management, and Performance Assessment. Those processes are described in detail within this document. Additionally, lessons learned and suggestions for future improvements are indicated.
This report details the work done under Sandia`s Photovoltaic Concentrator Development contract, funded jointly by Alpha Solarco and the US Department of Energy. It discusses improvements made to the cell assembly and module design of Alpha Solarco`s point-focus, high-concentration photovoltaic module. The goals of this effort were to increase the module efficiency, reduce the manufacturing cost of the cell assembly, and increase product reliability. Redesign of the secondary optical element achieved a 4 percent increase in efficiency due to better cell fill factors and offtrack performance. New, lower cost materials were identified for the secondary optical element, the optical couple between the secondary optical element and the cell, and the cell assembly electrical insulator. Manufacturing process improvements and test equipment are also discussed.
This project involved the manufacturing of curved-faceted, injection-molded, four-element Fresnel lens parquets for concentrating photovoltaic arrays. Previous efforts showed that high-efficiency (greater than 82%) Fresnel concentrators could be injection molded. This report encompasses the mold design, molding, and physical testing of a four-lens parquet for a solar photovoltaic concentrator system.
This research has produced a variety of monodisperse, nanometer-size clusters (nanoclusters for short), characterized their size and crystal structure and developed a scientific understanding of the size dependence of their physical properties. Of specific interest were the influence of quantum electronic confinement on the optical properties, magnetic properties, and dielectric properties. These properties were chosen both for their potential practical impact on various applications identified in the National Critical Technologies list (e.g., catalysis, information storage, sensors, environmental remediation, ...) as well as for their importance to the fundamental science of clusters. An Executive Summary provides a description of the major highlights.
A ground-based electrically-powered launcher could significantly reduce the complexity and cost of space launches for moderate-weight payloads. The EM launch complex could greatly reduce the amount of fuels handling, reduce the turnaround time between launches, allow more concurrence in launch preparation, reduce the manpower requirements for launch vehicle preparation and increase the reliability of launch by using more standardized vehicle preparations. The launch requires high acceleration, so the satellite package must be hardened. This paper presents results of a study to estimate the required launcher parameters, and estimate the cost of such a launch facility. This study is based on electromagnetic gun technology which is constrained to a coaxial geometry to take advantage of the efficiency of closely-coupled coils. The launcher energy and power requirements fall in the range of 40 {minus} 260 GJ and 20 {minus} 400 GW electric. Parametric evaluations have been conducted with a launcher length of 1-2 km, exit velocity of 1-6 kn/s, and payloads to low earth orbit of 100 1000 kg.
The mission of the Robotics Technology Development Program involves the following: develop robotic systems where justified by safety, cost, and/or efficiency arguments; integrate the best talent from National Labs, industry, and universities in focused teams addressing complex-wide problems; and involve customers in the identification and development of needs driven technologies. This presentation focuses on five areas. They are: radioactive tank waste remediation (Richland); mixed waste characterization, treatment, and disposal (Idaho Falls); decontamination and decommissioning (Morgantown); landfill stabilization (Savannah River); and contaminant plumes containment and remediation (Savannah River).
We conducted hydrostatic and constant-stress-difference (CSD) experiments at room temperature on two different sintered batches of poled, niobium-doped lead-zirconate-titanate ceramic (PZT 95/5-2Nb). The objective of this test plan was to quantify the effects of nonhydrostatic stress on the electromechanical behavior of the ceramic during the ferroelectric, rhombohedral {yields} antiferroelectric, orthorhombic (FE {yields} AFE) phase transformation. We also performed a series of hydrostatic and triaxial compression experiments in which a 1000 V potential was applied to poled specimens to evaluate any effect of a sustained bias on the transformation. As we predicted from earlier tests on unpoled PZT 95/5-2Nb, increasing the stress difference up to 200 MPa (corresponding to a maximum resolved shear stress of 100 MPa) decreases the mean stress and confining pressure at which the transformation occurs by 25--33%, for both biased and unbiased conditions. This same stress difference also retards the rate of transformation at constant pressurization rate, resulting in reductions of up to an order of magnitude in the rate of charge release and peak voltage attained in our tests. This shear stress-voltage effect offers a plausible, though qualitative explanation for certain systematic failures that have occurred in neutron generator power supplies when seemingly minor design changes have been made. Transformation strains in poled ceramic are anisotropic (differing by up to 33%) in hydrostatic compression, and even more anisotropic under non-hydrostatic stress states. Application of a 1000 V bias appears to slightly increase (by {le}2%) the transformation pressure for poled ceramic, but evidence for this conclusion is weak.
Aztec is an iterative library that greatly simplifies the parallelization process when solving the linear systems of equations Ax = b where A is a user supplied n x n sparse matrix, b is a user supplied vector of length n and x is a vector of length n to be computed. Aztec is intended as a software tool for users who want to avoid cumbersome parallel programming details but who have large sparse linear systems which require an efficiently utilized parallel processing system. A collection of data transformation tools are provided that allow for easy creation of distributed sparse unstructured matrices for parallel solution. Once the distributed matrix is created, computation can be performed on any of the parallel machines running Aztec: nCUBE 2, IBM SP2 and Intel Paragon, MPI platforms as well as standard serial and vector platforms. Aztec includes a number of Krylov iterative methods such as conjugate gradient (CG), generalized minimum residual (GMRES) and stabilized biconjugate gradient (BICGSTAB) to solve systems of equations. These Krylov methods are used in conjunction with various preconditioners such as polynomial or domain decomposition methods using LU or incomplete LU factorizations within subdomains. Although the matrix A can be general, the package has been designed for matrices arising from the approximation of partial differential equations (PDEs). In particular, the Aztec package is oriented toward systems arising from PDE applications.
A readout detector integrated circuit (IC) has been developed which is capable of detecting nano-ampere photo-current signals of interest in a high (micro-ampere) background illumination or DC noise level (SNR=92dB). The readout detector sensor IC processes transient signals of interest from a separate photodiode array chip. Low noise signal conditioning, filtering, and signal thresholding implement smart sensor detection of only ``active pixels.`` This detector circuit can also be used to perform signal conditioning for other sensor applications that require detection of very small signals in a high background noise environment.
The crust and mantle of the Earth are primarily composed of silicates. The properties of these materials under compression are of interest for deducing deep-earth composition. As well, the properties of these materials under shock compression are of interest for calculating groundshock propagation. The authors have synthesized, characterized, and performed Hugoniot measurements on monolithic polycrystalline SiO{sub 2} samples which were predominantly stishovite (a high-pressure polymorph). Synthesis was accomplished in a multianvil press with pyrophyllite gaskets and carbon heaters. The samples had densities ranging from 3.80 to 4.07, corresponding to stishovite volume fractions of 0.7 to 0.87, a range confirmed by NMR analysis. Electron microprobe and X-ray fluorescence characterizations showed minor carbon contamination (< 1%), with no other significant impurities. Samples {approximately} 1 mm thick and 3 mm diameter were tested in reverse and forward-ballistics modes on a two-stage light gas gun, using velocity interferometry diagnostics. Impact velocities ranged from 4.0 to 6.5 km/sec. Hugoniot stresses for four tests ranged from 65 to 225 GPa. At higher stresses significant uncertainties arise due to impact tilt/nonplanarity issues. Results are consistent with earlier predictions of the stishovite Hugoniot based on quartz-centered Hugoniot data, static-compression (diamond-anvil cell) data and hydrostatic multianvil cell data. Release behavior appears to be frozen. These results are remarkable in view of the small size of the samples used. Results are compared with current EOS models.
The Department of Energy Order 55OO.3A requires facility-specific hazards assessments be prepared, maintained, and used for emergency planning purposes. This hazards assessment document describes the chemical and radiological hazards associated with the AML. The entire inventory was screened according to the potential airborne impact to onsite and offsite individuals. The air dispersion model, ALOHA, estimated pollutant concentrations downwind from the source of a release, taking into consideration the toxicological and physical characteristics of the release site, the atmospheric conditions, and the circumstances of the release. The greatest distance at which a postulated facility event will produce consequences exceeding the Early Severe Health Effects threshold is 23 meters. The highest emergency classification is a General Emergency. The Emergency Planning Zone is a nominal area that conforms to DOE boundaries and physical/jurisdictional boundaries such as fence lines and streets.
Finding innovative ways to reduce waste streams generated at US Department of Energy (DOE) sites by 50% by the year 2000 is a challenge for DOE`s waste minimization efforts. A team composed of members from several DOE facilities used the quality tool known as benchmarking to improve waste minimization efforts. First the team examined office waste generation and handling processes at their sites. Then team members developed telephone and written questionnaires to help identify potential ``best-in-class`` industry partners willing to share information about their best waste minimization techniques and technologies. The team identified two benchmarking partners, NIKE, Inc., in Beaverton, Oregon, and Microsoft, Inc., in Redmond, Washington. Both companies have proactive, employee-driven environmental issues programs. Both companies report strong employee involvement, management commitment, and readily available markets for recyclable materials such as white paper and nonwhite assorted paper. The availability of markets, the initiative and cooperation of employees, and management support are the main enablers for their programs. At both companies, recycling and waste reduction programs often cut across traditional corporate divisions such as procurement, janitorial services, environmental compliance, grounds maintenance, cafeteria operations, surplus sales, and shipping and receiving. These companies exhibited good cooperation between these functions to design and implement recycling and waste reduction programs.