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Jump to search filtersThe lustering of TBC-2
Diver, R.B.; Jones, S.; Robb, S.; Mahoney, A.R.
Two test bed concentrators (TBCs) were designed to provide high-performance test beds for advanced solar receivers and converters. However, the second-surface silvered-glass mirror facets on the TBCs, which were originally manufactured by the Jet Propulsion Laboratory, have experienced severe silver corrosion. To restore reflectance, TBC-2 was refurbished with a lustering technique developed at Sandia National Laboratories. In the lustering technique, second-surface silvered thin-glass mirrors were applied over the corroded facets, thereby increasing the dish reflectivity and raising the available power of TBC-2 from approximately 70 to 78 kW{sub t}. Degradation of the original optical accuracy of the TBC facets was determined to be minimal. Lustering was chosen over facet replacement because of the lower cost, the anticipated improvement in corrosion resistance, and the shorter project duration. This report includes background information, details of the lustering process, and test results from TBC-2 characterization, both before and after lustering.
Synthesis of silicon nitride powders in pulsed RF plasmas
Nanometer size silicon nitride particles are synthesized using a pulsed radio frequency plasma technique. The plasma is modulated with a square-wave on/off cycle of varying period to control size and morphology and to deduce the growth kinetics. In situ laser light scattering and ex situ particle analysis are used to study the nucleation and growth. For SiH{sub 4}/Ar plasmas which nucleate silicon particles, an initial extremely rapid growth phase is followed by a slower growth rate, approaching the rate of thin film deposition on adjacent flat surfaces. In SiH{sub 4}/NH{sub 3} plasmas, silicon nitride particle size can be tightly controlled by adjusting the plasma-on time. The size dispersion of the particles is large and is consistent with a process of continual nucleation during the plasma-on period. The observed polydispersity differs dramatically from that reported from other laboratories.
Capacitive sensor for high resolution weld seam tracking
A non-contact capacitive sensing system has been developed for guiding automated welding equipment along typical v-groove geometries. The Multi-Axis Seam Tracking (MAST) sensor has been designed to produce four electric fields for locating and measuring the v-groove geometry. In this system, the MAST sensor is coupled with a set of signal conditioning electronics making it possible to output four varying voltages proportional to the electric field perturbations. This output is used for motion control purposes by the automated welding platform to guide the weld torch directly over the center of the v-groove. This report discusses the development of this capacitive sensing system. A functional description of the system and MAST sensor response characteristics for typical weld v-groove geometries are provided. The effects of the harsh thermal and electrical noise environments of plasma arc welding on sensor performance are discussed. A comparison of MAST sensor fabrication from glass-epoxy and thick-film ceramic substrates is provided. Finally, results of v-groove tracking experiments on a robotic welding platform are described.
Self-consistent temperature compensation for resonant sensors with application to quartz bulk acoustic wave chemical sensors
Smith, J.H.; Senturia, S.D.
Since resonant sensors have a temperature sensitivity which is often greater than their sensitivity to the phenomena they are being used to detect, it is imperative to include either temperature control or temperature compensation in any resonant sensor system. The authors have developed a temperature-compensation scheme for resonant sensors which is amenable to integration into a resonator-driver integrated circuit. An integrated circuit incorporating this scheme has been designed, built, and tested.
Enhancement of surface processes with low energy ions
Chason, E.
Continuing trends in device fabrication towards smaller feature sizes, lower thermal budgets and advanced device structures put greater emphasis on controlling the surface structure and reactivity during processing. Since the evolution of the semiconductor surface during processing is determined by the interaction of multiple surface processes, understanding how to control and modify these processes on the atomic level would enable us to exert greater control over the resulting morphology and composition. Low energy ions represent one method for bringing controlled amounts of energy to the surface to modify surface structure and kinetics. The kinetic energy deposited by the ions can break bonds and displace atoms, creating defect populations significantly in excess of the equilibrium concentration. Consequences of these non-equilibrium conditions include the enhancement of surface kinetic processes, increased surface reactivity and formation of metastable structures and compositions. These effects can be beneficial (ion enhanced mass transport can lead to surface smoothing) or they can be detrimental (residual defects can degrade electrical properties or lead to amorphization). The net results depend on a complex balance that depends on many parameters including ion mass, energy, flux and temperature. In the following section, we review progress both in our fundamental understanding of the production of low-energy ion-induced defects and in the use of low energy ions to enhance surface morphology, stimulate low temperature growth and obtain non-equilibrium structures and compositions.
Kauai Test Facility hazards assessment document
Banda Jr., Zeferino
The Department of Energy Order 55003A requires facility-specific hazards assessment be prepared, maintained, and used for emergency planning purposes. This hazards assessment document describes the chemical and radiological hazards associated with the Kauai Test Facility, Barking Sands, Kauai, Hawaii. The Kauai Test Facility`s chemical and radiological inventories were screened according to 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 to the Early Severe Health Effects threshold is 4.2 kilometers. The highest emergency classification is a General Emergency at the {open_quotes}Main Complex{close_quotes} and a Site Area Emergency at the Kokole Point Launch Site. The Emergency Planning Zone for the {open_quotes}Main Complex{close_quotes} is 5 kilometers. The Emergency Planning Zone for the Kokole Point Launch Site is the Pacific Missile Range Facility`s site boundary.
Determination of kinetic coefficients for the simultaneous reduction of sulfate and uranium by Desulfovibrio desulfuricans bacteria
Uranium contamination of groundwaters and surface waters near abandoned mill tailings piles is a serious concern in many areas of the western United States. Uranium usually exists in either the U(IV) or the U(VI) oxidation state. U(VI) is soluble in water and, as a result, is very mobile in the environment. U(IV), however, is generally insoluble in water and, therefore, is not subject to aqueous transport. In recent years, researchers have discovered that certain anaerobic microorganisms, such as the sulfate-reducing bacteria Desulfovibrio desulfuricans, can mediate the reduction of U(VI) to U(IV). Although the ability of this microorganism to reduce U(VI) has been studied in some detail by previous researchers, the kinetics of the reactions have not been characterized. The purpose of this research was to perform kinetic studies on Desulfovibrio desulficans bacteria during simultaneous reduction of sulfate and uranium and to determine the phase in which uranium exists after it has been reduced and precipitated from solution. The studies were conducted in a laboratory-scale chemostat under substrate-limited growth conditions with pyruvate as the substrate. Kinetic coefficients for substrate utilization and cell growth were calculated using the Monod equation. The maximum rate of substrate utilization (k) was determined to be 4.70 days{sup {minus}1} while the half-velocity constant (K{sub s}) was 140 mg/l COD. The yield coefficient (Y) was determined to be 0.17 mg cells/mg COD while the endogenous decay coefficient (k{sub d}) was calculated as 0.072 days{sup {minus}1}. After reduction, U(IV) Precipitated from solution in the uraninite (UO{sub 2}) phase. Uranium removal efficiency as high as 90% was achieved in the chemostat.
Design and analysis of a high-performance shipping container for large payloads
The packaging, designated the H1636A is a high-performing packageing for large payloads. The H1636A is 50 in. in diameter and 113 in. in length and weighs approximately 4600 lb when empty. The design objective was to meet 1996 proposed IAEA Type C criteria for air transport of large quantities of radioactive material (RAM). That is, the package should survive the standard Type B tests and more severe tests such as an impact onto an unyielding target at 280 ft/s and a one-hour jet fuel fire. The packaging consists of a large double-walled stainless steel outer drum filled with uniform density polyurethane foam. A stainless steel containment vessel (CV) with an inside diameter of 23 in. and a length of 78 in. carries the RAM. The CV has a nominal thickness of 0.375 in. and seals with two elastomeric 0-rings. The lid of the CV is joined to the body with a unique closure called a tape joint. The tape joint utilizes interlocking features preloaded with wedges and can withstand significant deformation.
High average power, high current pulsed accelerator technology
Which current pulsed accelerator technology was developed during the late 60`s through the late 80`s to satisfy the needs of various military related applications such as effects simulators, particle beam devices, free electron lasers, and as drivers for Inertial Confinement Fusion devices. The emphasis in these devices is to achieve very high peak power levels, with pulse lengths on the order of a few 10`s of nanoseconds, peak currents of up to 10`s of MA, and accelerating potentials of up to 10`s of MV. New which average power systems, incorporating thermal management techniques, are enabling the potential use of high peak power technology in a number of diverse industrial application areas such as materials processing, food processing, stack gas cleanup, and the destruction of organic contaminants. These systems employ semiconductor and saturable magnetic switches to achieve short pulse durations that can then be added to efficiently give MV accelerating, potentials while delivering average power levels of a few 100`s of kilowatts to perhaps many megawatts. The Repetitive High Energy Puled Power project is developing short-pulse, high current accelerator technology capable of generating beams with kJ`s of energy per pulse delivered to areas of 1000 cm{sup 2} or more using ions, electrons, or x-rays. Modular technology is employed to meet the needs of a variety of applications requiring from 100`s of kV to MV`s and from 10`s to 100`s of kA. Modest repetition rates, up to a few 100`s of pulses per second (PPS), allow these machines to deliver average currents on the order of a few 100`s of mA. The design and operation of the second generation 300 kW RHEPP-II machine, now being brought on-line to operate at 2.5 MV, 25 kA, and 100 PPS will be described in detail as one example of the new high average power, high current pulsed accelerator technology.
Qualification of environmentally friendly cleaners
De Marquis, G.; Lopez, E.P.
Sandia National Laboratories (SNL) has traditionally used chlorinated and fluorinated organic solvents for general degreasing applications. Many of these solvents have been labeled by the Federal Government as ozone depleting chemicals and as toxic and/or suspected carcinogens. As a result, these solvents will no longer be recommended for use within the DOE weapons complex. There are three major classes of materials that are of concern for cleaning: organics, metals and ceramics. Each of these materials has its own special cleaning problems. Solvents that were used in the past, such as 1,1,1-trichloroethane (TCA) and trichloroethylene (TCE), were extremely efficient at removing everything from oils and greases to salts without leaving corrosive residues or permanently absorbing into the materials. These traditional degreasing solvents were essentially ``all-inone`` cleaners: quick, reliable, and easy to use. Unfortunately, a ``drop-in`` cleaner for such a wide variety of materials and contaminants will probably never be identified. So far, it has been difficult to identify environmentally conscious cleaners that clean as well as TCE and TCA. Most alternative cleaners require more volume to do the job, and also require longer exposure to get the job done. With these things in mind, we are hoping to identify and qualify new cleaners that will take care of general classes of materials.
An overview of weapons technologies used to improve US healthcare
Fahrenholtz, J.
At Sandia National Laboratories the Biomedical Engineering Program uses existing weapons-related technology in medical applications in order to reduce health care costs, improve diagnoses, and promote efficient health care delivery. This paper describes several projects which use Sandia technologies to solve biomedical problems. Specific technical capabilities that are important to this program include sensor data interpretation, robotics, lasers and optics, microelectronics, image processing and materials.
The state-of-the-art port of entry workshop
Godfrey, B.
The increased demand for freight movements through international ports of entry and the signing of the North American Free Trade Agreement (NAFTA) have increased freight traffic at border ports of entry. The State-of-the-Art Port of Entry Workshop initiated a dialogue among technologists and stakeholders to explore the potential uses of technology at border crossings and to set development priorities. International ports of entry are both information and labor intensive, and there are many promising technologies that could be used to provide timely information and optimize inspection resources. Participants universally held that integration of technologies and operations is critical to improving port services. A series of Next Steps was developed to address stakeholder issues and national priorities, such as the National Transportation Policy and National Drug Policy. This report documents the views of the various stakeholders and technologists present at the workshop and outlines future directions of study.
Damage evolution in metal matrix composites subjected to thermomechanical fatigue
Allen, D.H.; Hurtado, L.D.; Helms, K.L.E.
A thermomechanical analysis of unidirectional continuous fiber metal matrix composites is presented. The analysis includes the effects of processing induced residual thermal stresses, interface cracking, and inelastic matrix behavior on damage evolution. Due to the complexity of the nonlinear effects, the analysis is performed computationally using the finite element method. The interface fracture is modeled by a nonlinear constitutive model. The problem formulation is summarized and results are presented for a four-ply unidirectional SCS-6/{beta}21S titanium composite under high temperature isothermal mechanical fatigue.
Fullerene-based materials research and development. LDRD final report
Cahill, P.A.; Henderson, C.C.; Rohlfing, C.M.; Loy, D.A.; Assink, R.A.; Gillen, K.T.; Jacobs, S.J.; Dugger, M.T.
The chemistry and physical properties of fullerenes, the third, molecular allotrope of carbon, have been studied using both experimental and computational techniques. Early computational work investigated the stability of fullerene isomers and oxides, which was followed by extensive work on hydrogenated fullerenes. Our work led to the first synthesis of a polymer containing C{sub 60} and the synthesis of the simplest hydrocarbon derivatives of C{sub 60} and C{sub 70}. The excellent agreement between theory and experiment ({plus_minus} 0.1 kcal/mol in the relative stability of isomers) has provided insight into the chemical nature of fullerenes and has yielded a sound basis for prediction of the structure of derivatized fullerenes. Such derivatives are the key to the preparation of fullerene-based materials.
Measures of effectiveness for BMD mid-course tracking on MIMD massively parallel computers
The TRC code, a mid-course tracking code for ballistic missiles, has previously been implemented on a 1024-processor MIMD (Multiple Instruction -- Multiple Data) massively parallel computer. Measures of Effectiveness (MOE) for this algorithm have been developed for this computing environment. The MOE code is run in parallel with the TRC code. Particularly useful MOEs include the number of missed objects (real objects for which the TRC algorithm did not construct a track); of ghost tracks (tracks not corresponding to a real object); of redundant tracks (multiple tracks corresponding to a single real object); and of unresolved objects (multiple objects corresponding to a single track). All of these are expressed as a function of time, and tend to maximize during the time in which real objects are spawned (multiple reentry vehicles per post-boost vehicle). As well, it is possible to measure the track-truth separation as a function of time. A set of calculations is presented illustrating these MOEs as a function of time for a case with 99 post-boost vehicles, each of which spawns 9 reentry vehicles.
Hanford coring bit temperature monitor development testing results report
Instrumentation which directly monitors the temperature of a coring bit used to retrieve core samples of high level nuclear waste stored in tanks at Hanford was developed at Sandia National Laboratories. Monitoring the temperature of the coring bit is desired to enhance the safety of the coring operations. A unique application of mature technologies was used to accomplish the measurement. This report documents the results of development testing performed at Sandia to assure the instrumentation will withstand the severe environments present in the waste tanks.
A one piece wall box for space electronics
In extraterrestrial applications, satellite payloads have printed circuit modules that are housed in boxes or chassis. The box may be a one piece wall or a segmented wall. These two wall options are compared for function and cost.
Deformation study of separator pellets for thermal batteries
The deformation characteristics of pellets of electrolyte-binder (EB) mixes based on MgO were measured under simulated, thermal-battery conditions. Measurements (using a statistically designed experimental strategy) were made as a function of applied pressure, temperature, and percentage of theoretical density for four molten-salt electrolytes at two levels of MgO. The EB mixes are used as separators in Li-alloy thermal batteries. The electrolytes included LiCl-KCI eutectic, LiCl-LiBr-KBr eutectic, LiBr-KBr-LiF eutectic, and a LiCl-LiBr-LiF electrolyte with a minimum-melting composition. The melting points ranged from 313 C to 436 C. The experimental data were used to develop statistical models that approximate the deformation behavior of pellets of the various EB mixes over the range of experimental conditions we examined. This report, discusses the importance of the deformation response surfaces to thermal-battery design.
Passive soil venting at the Chemical Waste Landfill Site at Sandia National Laboratories, Albuquerque, New Mexico
Passive Soil Vapor Extraction was tested at the Chemical Waste Landfill (CWL) site at Sandia National Laboratories, New Mexico (SNLIW). Data collected included ambient pressures, differential pressures between soil gas and ambient air, gas flow rates into and out of the soil and concentrations of volatile organic compounds (VOCS) in vented soil gas. From the differential pressure and flow rate data, estimates of permeability were arrived at and compared with estimates from other studies. Flow, differential pressure, and ambient pressure data were collected for nearly 30 days. VOC data were collected for two six-hour periods during this time. Total VOC emissions were calculated and found to be under the limit set by the Resource Conservation and Recovery Act (RCRA). Although a complete process evaluation is not possible with the data gathered, some of the necessary information for designing a passive venting process was determined and the important parameters for designing the process were indicated. More study is required to evaluate long-term VOC removal using passive venting and to establish total remediation costs when passive venting is used as a polishing process following active soil vapor extraction.
Sandia National Laboratories (SNL) and Oak Ridge National Laboratories (ORNL) joint development of SNL`s sample tracking, analysis and reporting (STAR) information system
A comprehensive environmental sample management program allocates much of its resources to collecting, managing, and manipulating information. A computerized system that collects information at the field sampling point, tracks the sample to analytical labs and loads electronic data deliverables from these labs, while maintaining chain of custody and data integrity, is efficient and cost effective for providing consistent and accurate, legally defensible sample data. In June 1993, a team was formed to gather Sample Management Office requirements and begin development of a sample tracking system. This paper is an overview of experiences encountered when Sandia transferred and implemented sample software from the Waste Area Group (WAG6) at ORNL.
ITEP: A survey of innovative environmental restoration technologies in the Netherlands and France
Roberds, W.J.; Voss, C.F.; Hitchcock, S.A.
The International Technology Exchange Program (ITEP) of the Department of Energy`s (DOE`s) Office of Environmental Management (EM) is responsible for promoting the import of innovative technologies to better address EM`s needs and the export of US services into foreign markets to enhance US competitiveness. Under this program, potentially innovative environmental restoration technologies, either commercially available or under development in the Netherlands and France, were identified, described, and evaluated. It was found that 12 innovative environmental restoration technologies, which are either commercially available or under development in the Netherlands and France, may have some benefit for the DOE EM program and should be considered for transfer to the United States.
The vital issues process: Strategic planning for a changing world
The Vital Issues process (VIp) is a strategic planning tool initially developed by Sandia National Laboratories (SNL) for the Office of Foreign Intelligence (OFI)* of the US Department of Energy (DOE). It was further developed and refined through its application to a variety of strategic purposes for a range of public and semipublic organizations. The VIp provides a structured mechanism for assisting organizations in accomplishing specified objectives by identifying and prioritizing a portfolio of strategic issues, programmatic areas, or responses to a specified problem. It employs day-long panel meetings in a specified format to elicit a broad range of perspectives on a particular issue in a nonconfrontational manner and to facilitate the interaction and synthesis of diverse viewpoints on a specific topic. The VIp is unique in its incorporation of two primary approaches in each panel session: a qualitative or transactional segment, which entails the synthesis of the alternatives through negotiations or discussion, and a quantitative or net benefit maximization segment, an analytical approach, which involves prioritization of the alternatives using pairwise comparisons. This combination of facilitated group discussion and quantitative ranking provides input to strategic management decisions in the form of stakeholder-defined and -prioritized items as well as information on potential barriers to the implementation of policies and programs. This is the final volume in the series Identifying Vital Issues: New Intelligence Strategies for a New World, a three-volume set that gives an accounting of the VIp as implemented for OFI. This volume provides an in-depth description of the methodology used in the VIp.
A survey of environmental needs and innovative technologies in Germany
Voss, C.F.; Roberds, W.J.
The International Technology Program (IT?), formerly the international Technology Exchange Program (ITEP), of the Department of Energy`s (DOE`s) Office of Environmental Restoration and Waste Management (EM) is responsible for promoting: (1) the import of innovative technologies to better address EM`s needs; and (2) the export of US services into foreign markets to enhance US competitiveness. Under this program: (1) the environmental restoration market in Germany was evaluated, including the description of the general types of environmental problems, the environmental regulations, and specific selected contaminated sites; and (2) potentially innovative environmental restoration technologies, either commercially available or under development in Germany, were identified, described and evaluated. It was found that: (1) the environmental restoration market in Germany is very large, on the order of several billion US dollars per year, with a significant portion possibly available to US businesses; and (2) a large number (54) of innovative environmental restoration technologies, which are either commercially available or under development in Germany, may have some benefit to the DOE EM program and should be considered for transfer to the US.
Design, fabrication, and testing of a sodium evaporator for the STM4-120 kinematic Stirling engine
Rawlinson, K.S.; Adkins, D.R.
This report describes the development and testing of a compact heat-pipe heat exchanger kW(e) designed to transfer thermal energy from hot combustion gases to the heater tubes of a 25-kW(e) Stirling engine. In this system, sodium evaporates from a surface that is heated by a stream of hot gases. The liquid metal then condenses on the heater tubes of a Stirling engine, where energy is transferred to the engine`s helium working fluid. Tests on a prototype unit illustrated that a compact (8 cm {times} 13 cm {times} 16 cm) sodium evaporator can routinely transfer 15 kW(t) of energy at an operating vapor temperature of 760 C. Four of these prototype units were eventually used to power a 25-kW(e) Stirling engine system. Design details and test results from the prototype unit are presented in this report.