The 34-meter Test Bed is a research-oriented, variable-speed vertical-axis wind turbine located at the USDA Agricultural Research Station in Bushland, Texas. Sandia National Laboratories designed and built this machine to perform research in structural dynamics, aerodynamics, and fatigue. Testing to determine its performance in various wind conditions and rotation rates has been ongoing for over three years. This report documents a broad range of test data and includes comparisons to analytical results.
Mechanical properties of the tuffaceous rocks within Yucca Mountain are needed for near and far-field modeling of the potential nuclear waste repository. If the mechanical properties are significantly anisotropic (i.e., direction-dependent), a more complex model is required. Relevant data from tuffs tested in earlier studies indicate that elastic and strength properties are anisotropic. This scoping study confirms the elastic anisotropy and concludes some tuffs are transversely isotropic. An approach for sampling and testing the rock to determine the magnitude of the anisotropy is proposed.
This report describes an assessment of the long-term performance of a repository system that contains deeply buried highly radioactive waste; the system is assumed to be located at the potential site at Yucca Mountain, Nevada. The study includes an identification of features, events, and processes that might affect the potential repository, a construction of scenarios based on this identification, a selection of models describing these scenarios (including abstraction of appropriate models from detailed models), a selection of probability distributions for the parameters in the models, a stochastic calculation of radionuclide releases for the scenarios, and a derivation of complementary cumulative distribution functions (CCDFs) for the releases. Releases and CCDFs are calculated for four categories of scenarios: aqueous flow (modeling primarily the existing conditions at the site, with allowances for climate change), gaseous flow, basaltic igneous activity, and human intrusion. The study shows that models of complex processes can be abstracted into more simplified representations that preserve the understanding of the processes and produce results consistent with those of more complex models.
This report discusses methods for making synthetic fuels from various kinds of wastes. Basic chemistry of synthesis gas creation and conversion is covered. Potentially productive wastes discussed are landfill natural gas, agricultural wastes, municipal wastes, industrial wastes, biomass, and tires. (VC)
Accurate alignment and focus of mirror facets are critical for the integration of concentrators and receivers in many of the low-cost stretched-membrane concentrators currently under development. In this report, the theoretical development of computer software that traces light rays from a source to a facet of a point-focusing solar concentrator and then to a target is given. Examples of approaches for the alignment of faceted point-focusing solar concentrators, which make use of targets generated by this computer program, are also presented.
This review of ongoing research at Sandia National Laboratory in the areas of nuclear weapons development and testing, arms control. As a multiprogram laboratory, their core competencies make special contributions in other areas of national importance. Work on US DOE programs is presented on the following subjects: robots; computers: arms control; nuclear weapons reliability; fusion research; solar energy; semiconductor detectors; radioactive waste management; nuclear explosion detection; and others. The laboratories strategic plan and other management methods are outlined. (GHH)
The efficient operation of a Stirling engine requires the application of a high heat flux to the relatively small area occupied by the heater head tubes. Previous attempts to couple solar energy to Stirling engines generally involved directly illuminating the heater head tubes with concentrated sunlight. In this study, operation of a 75-kW{sub t} sodium reflux pool-boiler solar receiver has been demonstrated and its performance characterized on Sandia's nominal 75-kW{sub t} parabolic-dish concentrator, using a cold-water gas-gap calorimeter to simulate Stirling engine operation. The pool boiler (and more generally liquid-metal reflux receivers) supplies heat to the engine in the form of latent heat released from condensation of the metal vapor on the heater head tubes. The advantages of the pool boiler include uniform tube temperature, leading to longer life and higher temperature available to the engine, and decoupling of the design of the solar absorber from the engine heater head. The two-phase system allows high input thermal flux, reducing the receiver size and losses, therefore improving system efficiency. The receiver thermal efficiency was about 90% when operated at full power and 800{degree}C. Stable sodium boiling was promoted by the addition of 35 equally spaced artificial cavities in the wetted absorber surface. High incipient boiling superheats following cloud transients were suppressed passively by the addition of small amounts of xenon gas to the receiver volume. Stable boiling without excessive incipient boiling superheats was observed under all operating conditions. The receiver developed a leak during performance evaluation, terminating the testing after accumulating about 50 hours on sun. The receiver design is reported here along with test results including transient operations, steady-state performance evaluation, operation at various temperatures, infrared thermography, x-ray studies of the boiling behavior, and a postmortem analysis.
This report describes a hardware implementation of a fast fourier transform (FFT) based real time data compression system. The system is currently configured to compress and analyze airborne vehicle vibration data but it can be utilized for compressing any one- dimensional data stream. The algorithm uses a two-stage process to compress successive stationary time periods of input data. The first stage compresses data by transforming continuous blocks of 2048 points to the frequency domain using Welch's method. The second stage provides further compression by logarithmically averaging adjacent frequency bins of the transformed signal. These compression techniques result in a bandwidth savings from 8:1 to 64:1 per channel compared to strictly analog or digital transmission techniques. The complete technique as well as the hardware used to implement it is described in detail in this report.
We have developed a controlled environment system in which to perform wetting experiments to analyze the effects of various atmospheres, both inert and reducing, on solder processing. This system consists of a custom designed vacuum chamber, an apparatus for heating specimens and a video system for data acquisition. The system design allows for rapid changes to various processing atmospheres. Specimens can be heated to soldering temperature from room temperature rapidly. The temperature is regulated by a controller which gives a maximum heating rate of 23{degrees}C/second while minimizing the amount of overshoot, thereby quickly a stabilized temperature. A video system is used to acquire the data in the form of both numerical data and real-time video images. The video system allows multiple views of the wetting process to be captured and simultaneously records time and temperature information. The recorded information is suitable for digital analysis. The controlled atmosphere soldering system has been used to perform experiments that examine the effect of inert and acid vapor atmospheres on solder wetting behavior.
As a multiprogram engineering laboratory, Sandia National Laboratories (SNL) has major research and development responsibilities for nuclear weapons, arms control, energy, environment, and other areas of strategic importance to national security. To accomplish this diversified mission, analysts within the Engineering Sciences Directorate support the entire laboratory using finite element and finite difference solution schemes to solve problems in fluid dynamics (steady state and transient, compressible and incompressible), thermodynamics (heat transfer), hydrodynamics (impact physics, penetration mechanics), solid mechanics (structural/thermal analysis, fracture mechanics, ground subsidence, impact modeling) and structural dynamics. To assist these analysts in performing these analyses most efficiently, the Applied Visualization Group was formed and tasked to develop a ``production scientific visualization environment.`` In this paper, we characterize a visualization environment that has been designed and prototyped for a large community of scientists and engineers. The proposed environment makes use of a visualization server concept to provide effective, interactive visualization to the user`s desktop. Benefits of using the visualization server approach are discussed. Some thoughts regarding desirable features for visualization server hardware architectures are also addressed. A brief discussion of the software environment is included. The paper concludes by summarizing certain observations which we have made regarding the implementation of such visualization environments.
Aryl-, ethynyl- and alkyl-bridged polysilsesquioxanes were prepared by the hydrolysis and condensation of the respective bridged triethoxysilanes under both acidic and basic conditions. Gelation of the resulting sols can take place at concentrations as low as 0.02 M in tetrahydrofuran. The gels can be air dried to afford xerogels or extracted with supercritical carbon dioxide to give high surface area aerogels. The materials were characterized by solid state {sup 13}C and {sup 29}Si CP MAS NMR spectroscopies, gas sorption porosimetry, and thermal gravimetric analysis. The bridged polysilsesquioxanes offer the opportunity to prepare hybrid organic-inorganic materials with properties unique from other siloxane network materials and silica gels.
This paper describes current research and development on miniaturized sensing systems for use during in situ characterization of nuclear waste storage tanks, buried waste sites, and decommissioned production facilities. Each miniaturized sensor system will consist of a suite of chemical, radiological, and physical properties sensors integrated into a compact package which will be mounted on the end of a robotic arm and/or vehicle. While the specific size of this remote sensor head and the types of sensors included will depend on site needs, the supporting generic computing system may be used for other waste characterization applications. This computing system will contain all necessary hardware and software to acquire, combine, interpret, display, and archive a wide range of sensor data. This paper describes the present status of the project, the lessons learned from the first prototype, and planned future designs of the next generation system. 7 refs.
One of the principal objectives of the International Technology Exchange Program (ITEP) is the exchange of waste management and environmental restoration (WM/ER) technologies between the US and other nations. The current emphasis of ITEP is the transfer of technologies to the US that could provide better, faster, cheaper, or safer solutions to the needs of the DOE complex. The 10 candidate technologies that have been identified thus far by ITEP are discussed. The highlights of preliminary evaluations of these technologies through a systems approach are also described. The technologies have been evaluated by a screening process to determine their applicability to the leading WM/ER needs of the DOE complex. The technologies have been qualitatively compared with the known or anticipated capabilities of domestic, base case technologies.
During inspections of the Waste Isolation Pilot Plant Waste Shaft in May 1990, patchy areas of apparently degraded concrete were observed on the inner surface of the shaft liner between approximately 810 feet and 900 feet below the surface. The apparent cause of this degradation is chemical reaction of the concrete with magnesium-bearing brine in the annulus between the concrete liner and the host rock. The greater thickness of the degraded layer below the joint may be related to the different chemical compositions that were determined by analyses of the paste portions of concrete samples from above and below the joint. The analytical results support a complex mechanistic explanation of concrete degradation observed behind the liner and in the joint: chemical weakening of the concrete paste; cracking by precipitation of solids in pores; and increased permeability due to calcium chloroaluminate formation. Additional sampling, analyses, and regular monitoring are worth considering to bound the vertical extent of Waste Shaft liner degradation, detect concrete liner degradation in other shafts, and measure any ongoing degradation that may be occurring.
This paper presents recent progress in using finite-difference analysis codes to simulate the responses of complex structures due to direct lightning. Significant advances have been made in interfacing a finite-difference code with commercial computer aided design tools, in suppressing a pervasive instability associated with the thin-wire algorithm for modeling conductors much smaller than a cell size, and in visualizing the results with color movies. Preliminary comparisons between the results of the finite-difference code and the results obtained during a recent rocket-triggered lightning test are also presented. 3 refs.
Computer modeling of the blasting process can aid in gaining an understanding of the physics controlling the process. The sequence of events in a blast occur so rapidly and in such a violent environment that measurements are still difficult to obtain. Computer modeling using a program such as DMC [Taylor and Preece, 1989a, 1989b] can provide insights into the physics of the rapid and violent events associated with a blast. DMC has been used to simulate crater blasting [Preece, 1990c] and the blasting of Oil Shale for modified in-situ retorting [Preece, 1990a, 1990b]. This paper will address the influence that damping has on the velocity distribution in the rock mass during the rock motion phase of a blast. Since velocity distribution is a controlling factor of muck pile shape, damping also contributes to muck pile shape.
The most recent RADLAC experiments studied propagation and hose stability of a high current beam propagating in the atmosphere, and confirmed the convective nature of the hose instability. The unique combination of high beam current and extremely small initial perturbation, allowed saturation of the hose instability to be observed for the first time. Data on high current propagation was needed because the current scaling is more complex than energy scaling. It was important to collect data at atmospheric pressure to insure that subtle air chemistry effects such as avalanche did not distort the experiment. With this philosophy, the results should be directly scaleable to applications at higher energy.
The possibility of long-term smoke emissions (from 1 to 3 years) from burning Kuwaiti oil wells has increased concerns regarding personnel exposure and acute and chronic health effects. This document, which is the result of work done in the spring of 1991, addresses those concerns. Part 1 of this document describes follow-on efforts to the pre-war modeling studies of the toxicological hazards to exposed Kuwaiti populations. Part 2 describes a pollutant monitoring program that could be carried out in the summer of 1991 to measure real-time exposure levels and to obtain more detailed information about the pollutant source terms and meteorological conditions that are necessary inputs to model computations.
This project was a collaboration between Sandia National Laboratories and the Harvey E. Yates Company (Heyco), Roswell, NM, conducted under the auspices of Department of Energy`s Oil Recovery Technology Partnership. The project applied Sandia perspectives on the effects of natural fractures, stress, and sedimentology for the stimulation and production of low permeability gas reservoirs to low permeability oil reservoirs, such as those typified by the Bone Spring sandstones of the Delaware Basin, southeast New Mexico. This report details the results and analyses obtained in 1990 from core, logs, stress, and other data taken from three additional development wells. An overall summary gives results from all five wells studied in this project in 1989--1990. Most of the results presented are believed to be new information for the Bone Spring sandstones.
Waveguide-to-microstrip transitions are extremely important components of mm-wave communication systems because it is the interface between the signal processing circuitry and the transmitted/received signal. This report describes the design procedure, construction detail, and measurement of both 3 and 4 step stepped ridge waveguide (RWG) transitions. Both transitions had > 10 dB return loss over the frequency band of interest (57--63 GHz) while insertion loss was less than 1 dB. Also, the transition lengths were at least half as long as traditional finline transitions while having superior performance. These shorter lengths were achieved by violating the ``small-step`` assumption usually used in RWG transition design. 7 refs.
The most costly problem routinely encountered in geothermal drilling is lost circulation, which occurs when drilling fluid is lost to the formation rather than circulating back to the surface. The successful and economical treatment of lost circulation requires the accurate measurement of drilling fluid flow rate both into and out of the well. This report documents the development of a meter for measuring drilling fluid outflow rates in the return line of a drilling rig. The meter employs a rolling counterbalanced float that rides on the surface of the fluid in the return line. The angle of the float pivot arm is sensed with a pendulum potentiometer, and the height of the float is calculated from this measurement. The float height is closely related to the fluid height and, therefore, the flow rate in the line. The prototype rolling float meter was extensively tested under laboratory conditions in the Wellbore Hydraulics Flow Facility; results from these tests were used in the design of the field prototype rolling float meter. The field prototype meter was tested under actual drilling conditions in August and September 1991 at the Long Valley Exploratory Well near Mammoth Lakes, Ca. In addition, the performance of several other commercially available inflow and outflow meters was evaluated in the field. The tested inflow meters included conventional pump stroke counters, rotary pump speed counters, magnetic flowmeters, and an ultrasonic Doppler flowmeter. On the return flow line, a standard paddlemeter, an acoustic level meter, and the prototype rolling float meter were evaluated for measuring drilling fluid outflow rates.
This paper discusses the imaging radar technology requirements for the Open Skies regime including the unresolved issues to be discussed at future Open Skies Consultative Commission (OSCC) meetings. Compliance with international rules on shared technology is addressed and some of the practical considerations for operational deployment of the radar imaging equipment in an Open Skies aircraft are presented. The Open Skies Treaty requirements and validation methodologies for imaging radars that have been agreed on and those that will require future OSCC review are discussed.
Supercritical fluid technology has been used in industry for the extraction and separation of materials in a number of applications such as food preparation and petroleum processing. Gel-derived microcellular polymer foam technology, developed at Sandia, requires the extraction of organic solvents from thermally-induced phase separated gels to yield microcellular foams. We have applied supercritical fluid extraction technology to these specialized materials by using supercritical carbon dioxide to extract a variety of organic solvents from gels to produce foams. Our supercritical extraction process will be described, as well as high pressure equipment that is used to perform the extractions. The results of gel extraction trails and qualitative supercritical carbon dioxide/solvent miscibility experiments will also be presented. We plan to pursue other related areas in this field, including supercritical fluid cleaning, quantitative solubility studies, and supercritical fluid chromatography.
This document contains five appendices documenting how Sandia implemented the DOE Conduct of Operations (5480.19) and DOE Quality Assurance (5700.6C) orders. It provides a mapping of the Sandia integrated requirements to the specific requirements of each Order and a mapping to Sandia`s approved program for implementing the Conduct of Operations Order.
Many problems in computer applications can in theory be solved by searching through a directed-acyclic graph (DAG). In practice, however, this approach has been hampered by our analytical inability to predict the search cost accurately without actually implementing and executing the program. To overcome this inability, a simple and quick heuristic procedure based on a stratified sampling approach is presented. In generalizes a tree sampling technique already shown to be useful in predicting the performance of tree-searching programs. With the addition of this DAG sampling procedure, we should be able to forecast the complexity and feasibility of alternative tree or DAG searching algorithms so that we may utilize our computational resources more effectively.