Publications

A robust bearing estimation process for 3-component stations has been developed and explored. The method, called SEEC for Search, Estimate, Evaluate and Correct, intelligently exploits the in- herent information in the arrival at every step of the process to achieve near-optimal results. In particular, the approach uses a consistent framework to define the optimal time-frequency windows on which to make estimates, to make the bearing estimates themselves, to construct metrics helpful in choosing the better estimates or admitting that the bearing is immeasurable, andjinally to apply bias corrections when calibration information is available to yield a single final estimate. The method was applied to a small but challenging set of events in a seismically active region. The method demonstrated remarkable utility by providing better estimates and insights than previously available. Various monitoring implications are noted fiom these findings.

Oriented bicrystals of pure C11_b MoSi₂ have been grown in a tri-arc furnace using the Czochralski technique. Two single crystal seeds were used to initiate the growth. Each seed had the orientation intended for one of the grains of the bicrystals, which resulted in a 60° twist boundary on the (110) plane. Seeds were attached to a water-cooled seed rod, which was pulled at 120 mm/h with the seed rod rotating at 45 rpm. The water- cooled copper hearth was counter-rotated at 160 rpm. Asymmetric growth ridges associated with each seed crystal were observed during growth and confirmed the existence of a bicrystal. It was also found that careful alignment of the seeds was needed to keep the grain boundary from growing out of the boule. The resulting boundary was characterized by imaging and crystallographic techniques in a scanning electron microscope. The boundary was found to be fairly sharp and the misorientation between the grains remained within 2° from the disorientation between the seeds.

This paper discusses a new technique for measuring the impedance response of thickness shear mode (TSM) resonators used as fluid monitors and chemical sensors. The technique simulates the swept frequency measurements performed by an automatic network analyzer (ANA), determining the complex reflection scattering parameter, S1l, from single port devices. Unlike oscillator circuits most often used with TSM resonators, narrowband spectral measurements are not limited by cable capacitance between resonator and oscillator allowing placement of the sensor in severe environments. Only noise produced by long cable lengths limits performance and sensor sensitivity. This new technique utilizes a simple swept frequency source operating near the crystal resonance, a unique directional coupler to provide the reference and reflected RF signals, an I & Q demodulation circuit that returns two dc voltages, and computational algorithms for determining sensor response parameters. Performance, has been evaluated by comparing TSM resonator responses using this new technique to those from a commercial ANA.

The Instrumentation and Telemetry Departments at Sandia National Laboratories have been instrumenting earth penetrators for over thirty years. Recorded acceleration data is used to quantify penetrator performance. Penetrator testing has become more difficult as desired impact velocities have increased. This results in the need for small-scale test vehicles and miniature instrumentation. A miniature recorder will allow penetrator diameters to significantly decrease, opening the window of testable parameters. Full-scale test vehicles will also benefit from miniature recorders by using a less intrusive system to instrument internal arming, fusing, and firing components. This single channel concept is the latest design in an ongoing effort to miniaturize the size and reduce the power requirement of acceleration instrumentation. A micro-controller/memory based system provides the data acquisition, signal conditioning, power regulation, and data storage. This architecture allows the recorder, including both sensor and electronics, to occupy a volume of less than 1.5 cubic inches, draw less than 200mW of power, and record 15kHz data up to 40,000 gs. This paper will describe the development and operation of this miniature acceleration recorder.

To meet challenging constraints on telemetry system weight and volume, a custom Light-Weight Instrumentation System was developed to collect vehicle environment and dynamics on a short-duration exo-atmospheric flight test vehicle. The total telemetry system, including electronics, sensors, batteries, and a 1 watt transmitter weighs about 1 kg. Over 80 channels of measurement, housekeeping, and telemetry system diagnostic data are transmitted at 128 kbps. The microcontroller-based design uses the automotive industry standard Controller Area Network to interface with and support in-flight control fimctions. Operational parameters are downloaded via a standard asynchronous serial communications intefiace. The basic design philosophy and functionality is described here.

Experimentation in transparent fractures where light transmission techniques are used to measure aperture, dye concentration, and phase distribution fields can enhance our understanding of single and multi-phase flow and transport. Here, we evaluate and improve the method for aperture field measurement in transparent analog fractures and replicas of natural fractures. The primary sources of error in the measurements are: signal noise (both temporal and spatial) from the charge-coupled-device (CCD) used to measure light intensities transmitted through the fracture; non-linearity of light absorbance of the dyed solution used to fill the fracture; and refraction of light passing through the fracture. We find that each of these error sources can be minimized to optimize precision and accuracy. Our measurements of the aperture field of a -150 x 300 mm analog test fracture at a spatial resolution of 0.159 x 0.159 mm ( 2x10⁶ points) demonstrate a root-mean- square error over the field of O.9% (0.002 mm) of the mean aperture (0.222 mm). Though the results presented here are specific to our test fracture and measurement system, the general approach can be applied to other digital imaging techniques based on energy absorbance.

This report documents the assessment of performance and design of a 250-kW prototype battery energy storage system developed by Omnion Power Engineering Company and tested by Pacific Gas and Electric Company, both in collaboration with Sandia National Laboratories. The assess- ment included system performance, operator interface, and reliability. The report also discusses how to detect failed battery strings with strategically located voltage measurements.

Two major studies, one sponsored by the U.S. Department of Energy and the other by the U.S. Nuclear Regulatory Commission, were conducted in the late 1970s and early 1980s to provide information and source terms for an optimally successful act of sabotage on spent fuel casks typical of those available for use. This report applies the results of those studies and additional analysis to derive potential source terms for certain classes of sabotage events on spent fuel casks and spent fuel typical of those which could be shipped in the early decades of the 21st century. In addition to updating the cask and spent fuel characteristics used in the analysis, two release mechanisms not included in the earlier works were identified and evaluated. As would be expected, inclusion of these additional release mechanisms resulted in a somewhat higher total release from the postulated sabotage events. Although health effects from estimated releases were addressed in the earlier study conducted for U.S. Department of Energy, they have not been addressed in this report. The results from this report maybe used to estimate health effects.

This document details the instructional design and delivery methods for a course on the NWC Technical Business Practices that are used to enact configuration management of Nuclear Weapons Product and Equipment.

Subsurface barriers are being constructed at both government and private sites to control hazardous material migration. The Department of Energy, in particular, is developing new barrier construction methods and materials for applications in saturated and unsaturated soils. These containment systems are meant to control high-risk contaminants that are too difficult to remove with current methods and/or pose a near-term, high risk to public health. Such systems are also implemented at sites where remediation techniques may have unintentionally mobilized contamination and threatened the water table. Since subsurface barriers are typically applied in high-risk circumstances, knowledge of their emplaced and long-term integrity is crucial. Current verification and monitoring practices (hydraulic testing, construction materials and methods QA) are limited in their ability to locate, discriminate, and resolve flaws in barrier construction. SEAtracem is a gaseous tracer verification and monitoring system developed to locate and estimate the size of flaws in subsurface barriers located above the water table. The system incorporates injection of a non-hazardous gaseous tracer in the barrier interior, multiple soil vapor sampling points located outside of the barrier, and an automated sampling and analysis system. SEAtraceTM is an autonomous, remotely accessible monitoring system intended for long duration, unattended operation. It not only collects and analyzes soil gas samples, but also applies real time data inversion to locate and size flaws in the barrier construction. The SEAtraceTM methodology was deployed at two test barrier installations sponsored by the Department of Energy Subsurface Contaminants Focus Area. The first was a small scale thinwall jet wouting barrier demonstration at the Groundwater Remediation Field Laboratory, Dover Air Force Base, and the second a large scale thickwall colloidal silica permeation grouted barrier at the Brookhaven National Laboratory. At the Dover site two test barriers and one buried known leak source were evaluated using the SEAtracem methodology. A prototype automated soil gas sampling and analysis system provided data that was analyzed on a desktop computer system. During these tests six non-engineered and one engineered flaw were detected in the barrier panels. These flaws indicated the presence of open areas in the barrier panels that allowed diffusion of tracer gas out into the soil surrounding the barriers. The buried leak source was located within 0.2m of its actual position. A fully integrated SEAtracem system was deployed to test a colloidal silica barrier at Brookhaven National Laboratory. This system incorporated 64 sampling locations, real-time data analysis, solar powered operation, and remote access via cellular phone communication. Eleven flaws were located by automated operation of the SEAtracem system. Other verification techniques such as geophysics, hydraulics, and peffluorocarbon gaseous tracers were used at both the Dover and Brookhaven test barriers. Results from these techniques were in good agreement when they could be compared. This report documents the design of the SEAtracem system, the numerical analysis that supports the evaluation of the inversion methodology, the design of the test installations, and the demonstrations at the Dover and Brookhaven sites.

Bond-counting arguments, supported by ab-initio calculations, predict a lower barrier for "leapfrog" diffusion of Pt addimers on Pt(llO)-lx2 than for adatom dif- fusion or addimer dissociation. This conflicts with experiment, possibly signaling contaminant influence.

We are pleased to submit our efforts in parallelizing the PRONTO application suite for con- sideration in the SuParCup 99 competition. PRONTO is a finite element transient dynamics simulator which includes a smoothed particle hydrodynamics (SPH) capability; it is similar in scope to the well-known DYNA, PamCrash, and ABAQUS codes. Our efforts over the last few years have produced a fully parallel version of the entire PRONTO code which (1) runs fast and scalably on thousands of processors, (2) has performed the largest finite-element transient dynamics simulations we are aware of, and (3) includes several new parallel algorithmic ideas that have solved some difficult problems associated with contact detection and SPH scalability. We motivate this work, describe the novel algorithmic advances, give performance numbers for PRONTO running on Sandia's Intel Teraflop machine, and highlight two prototypical large-scale computations we have performed with the parallel code. We have successfully parallelized a large-scale production transient dynamics code with a novel algorithmic approach that utilizes multiple decompositions for different key segments of the computations. To be able to simulate a more than ten million element model in a few tenths of second per timestep is unprecedented for solid dynamics simulations, especially when full global contact searches are required. The key reason is our new algorithmic ideas for efficiently parallelizing the contact detection stage. To our knowledge scalability of this computation had never before been demonstrated on more than 64 processors. This has enabled parallel PRONTO to become the only solid dynamics code we are aware of that can run effectively on 1000s of processors. More importantly, our parallel performance compares very favorably to the original serial PRONTO code which is optimized for vector supercomputers. On the container crush problem, a Teraflop node is as fast as a single processor of the Cray Jedi. This means that on the Teraflop machine we can now run simulations with tens of millions of elements thousands of times faster than we could on the Jedi! This is enabling transient dynamics simulations of unprecedented scale and fidelity. Not only can previous applications be run with vastly improved resolution and speed, but qualitatively new and different analyses have been made possible.

The objective of this work to develop the materials processing and design technologies required to reduce the die development time for metal mold processes from 12 months to 3 months, using die casting of Al and Mg as the example process. Sandia demonstrated that investment casting, using rapid prototype patterns produced from Stereo lithography or Selective laser Sintering, was a viable alternative/supplement to the current technology of machining form wrought stock. A demonstration die insert (ejector halt) was investment cast and subsequently tested in the die casting environment. The stationary half of the die insert was machined from wrought material to benchmark the cast half. The two inserts were run in a die casting machine for 3,100 shots of aluminum and at the end of the run no visible difference could be detected between the cast and machined inserts. Inspection concluded that the cast insert performed identically to the machined insert. Both inserts had no indications of heat checking or degradation.

This document highlights the DISCOM's Distance computing and communication team activities at the 1998 Supercomputing conference in Orlando, Florida. This conference is sponsored by the IEEE and ACM. Sandia National Laboratories, Lawrence Livermore National Laboratory, and Los Alamos National Laboratory have participated in this conference for ten years. For the last three years, the three laboratories have a joint booth at the conference under the DOE's ASCI, Accelerated Strategic Computing Initiatives. The DISCOM communication team uses the forum to demonstrate and focus communications and networking developments. At SC '98, DISCOM demonstrated the capabilities of Dense Wave Division Multiplexing. We exhibited an OC48 ATM encryptor. We also coordinated the other networking activities within the booth. This paper documents those accomplishments, discusses the details of their implementation, and describes how these demonstrations support overall strategies in ATM networking.

A Fourier Transform hyperspectral imager uses optical intereferometry to obtain hyperspectral data. Taking a Fourier Transform of the interferogram yields the frequency spectrum of the incident light. An optical system using a standard frame rate camera can generate such interferograms at a rate of 30 frames per second. Rather than store all of the raw interferogram data and process it afterwards, it is useful to have the ability to process the raw data in real time, generating and storing the hyperspectral data itself rather than the original interferograms. This real-time processing would result in a significant reduction in the data bandwidth and storage requirements, which are of particular interest in typical airborne environments with limited computing resources on board. This report details the digital signal processing algorithm and code developed for a processing subsystem based on the Texas Instruments TMS320C6201 fixed point processor. The function of this subsystem is to compute the magnitude Fourier Transform of the interferogram data at a rate of 30 frames per second.

This report describes the results of a six-year, $6.3 million project to reduce operation and maintenance (O&M) costs at power plants employing concentrating solar power (CSP) technology. Sandia National Laboratories teamed with KJC Operating Company to implement the O&M Improvement Program. O&M technologies developed during the course of the program were demonstrated at the 150-MW Kramer Junction solar power park located in Boron, California. Improvements were made in the following areas: (a) efficiency of solar energy collection, (b) O&M information management, (c) reliability of solar field flow loop hardware, (d) plant operating strategy, and (e) cost reduction associated with environmental issues. A 37% reduction in annual O&M costs was achieved. Based on the lessons learned, an optimum solar- field O&M plan for future CSP plants is presented. Parabolic trough solar technology is employed at Kramer Junction. However, many of the O&M improvements described in the report are also applicable to CSP plants based on solar power tower or dish/engine concepts.

This report describes the results of a study that investigated the synergy between electrochemical capacitors (ECs) and flywheels, in combination with each other and with batteries, as energy storage subsystems in photovoltaic (PV) systems. EC and flywheel technologies are described and the potential advantages and disadvantages of each in PV energy storage subsystems are discussed. Seven applications for PV energy storage subsystems are described along with the potential market for each of these applications. A spreadsheet model, which used the net present value method, was used to analyze and compare the costs over time of various system configurations based on flywheel models. It appears that a synergistic relationship exists between ECS and flywheels. Further investigation is recommended to quantify the performance and economic tradeoffs of this synergy and its effect on overall system costs.

The Environmental Measurement-While-Drilling (EMWD) system and Horizontal Directional Drilling (HDD) were successfully demonstrated at the Mock Tank Leak Simulation Site and the Drilling Technology Test Site, Hanford, Washington. The use of directional drilling offers an alternative to vertical drilling site characterization. Directional drilling can develop a borehole under a structure, such as a waste tank, from an angled entry and leveling off to horizontal at the desired depth. The EMWD system represents an innovative blend of new and existing technology that provides the capability of producing real-time environmental and drill bit data during drilling operations. The technology demonstration consisted of the development of one borehole under a mock waste tank at a depth of {approximately} {minus}8 m ({minus}27 ft.), following a predetermined drill path, tracking the drill path to within a radius of {approximately}1.5 m (5 ft.), and monitoring for zones of radiological activity using the EMWD system. The purpose of the second borehole was to demonstrate the capability of drilling to a depth of {approximately} {minus}21 m ({minus}70 ft.), the depth needed to obtain access under the Hanford waste tanks, and continue drilling horizontally. This report presents information on the HDD and EMWD technologies, demonstration design, results of the demonstrations, and lessons learned.

The elevation change data measured at the Big Hill SPR site over the last 10 years has been studied and a model utilized to project elevation changes into the future. The subsidence rate at Big Hill is low in comparison with other Strategic Petroleum Reserve sites and has decreased with time due to the maintenance of higher operating pressures and the normal decrease in creep closure rate of caverns with time. However, the subsidence at the site is projected to continue. A model was developed to project subsidence values 20 years into the future; no subsidence related issues are apparent from these projections.

During July-September, 1998, a jointly funded drilling operation deepened the Long Valley Exploratory Well from 7178 feet to 9832 feet. This was the third major drilling phase of a project that began in 1989, but had sporadic progress because of discontinuities in tiding. Support for Phase III came from the California Energy Commission (CEC), the International Continental Drilling Program (ICDP), the US Geological Survey (USGS), and DOE. Each of these agencies had a somewhat different agenda: the CEC wants to evaluate the energy potential (specifically energy extraction from magma) of Long Valley Caldera; the ICDP is studying the evolution and other characteristics of young, silicic calderas; the USGS will use this hole as an observatory in their Volcano Hazards program; and the DOE, through Sandia, has an opportunity to test new geothermal tools and techniques in a realistic field environment. This report gives a description of the equipment used in drilling and testing; a narrative of the drilling operations; compiled daily drilling reports; cost information on the project; and a brief summary of engineering results related to equipment performance and energy potential. Detailed description of the scientific results will appear in publications by the USGS and other researchers.

This report includes the details of the model building procedure and prediction of seismic field data. Principal Components Regression, a multivariate analysis technique, was used to model seismic data collected as two pieces of equipment were cycled on and off. Models built that included only the two pieces of equipment of interest had trouble predicting data containing signals not included in the model. Evidence for poor predictions came from the prediction curves as well as spectral F-ratio plots. Once the extraneous signals were included in the model, predictions improved dramatically. While Principal Components Regression performed well for the present data sets, the present data analysis suggests further work will be needed to develop more robust modeling methods as the data become more complex.

Modern wind turbines are fatigue critical machines that are typically used to produce electrical power from the wind. Operational experiences with these large rotating machines indicated that their components (primarily blades and blade joints) were failing at unexpectedly high rates, which led the wind turbine community to develop fatigue analysis capabilities for wind turbines. Our ability to analyze the fatigue behavior of wind turbine components has matured to the point that the prediction of service lifetime is becoming an essential part of the design process. In this review paper, I summarize the technology and describe the ''best practices'' for the fatigue analysis of a wind turbine component. The paper focuses on U.S. technology, but cites European references that provide important insights into the fatigue analysis of wind turbines.

Studies have indicated that an adaptive wind turbine blade design can significantly enhance the performance of the wind turbine blade on energy capture and load mitigation. In order to realize the potential benefits of aeroelastic tailoring, a bend-twist D-spar, which is the backbone of a blade, was designed and fabricated to achieve the objectives of having maximum bend-twist coupling and fulfilling desirable structural properties (031 & GJ). Two bend-twist D-spars, a hybrid of glass and carbon fibers and an all-carbon D-spar, were fabricated using a bladder process. One of the D-spars, the hybrid D-spar, was subjected to a cantilever static test and modal testing. Various parameters such as materials, laminate schedule, thickness and internal rib were examined in designing a bend-twist D-spar. The fabrication tooling, the lay-up process and the joint design for two symmetric clamshells are described in this report. Finally, comparisons between the experimental test results and numerical results are presented. The comparisons indicate that the numerical analysis (static and modal analysis) agrees well with test results.

This report describes the characteristics of photovoltaic arrays that maybe suitable for use with nanosatellite electronic systems. It includes a thorough literature search on power management and distribution systems for satellites as small as microsatellites. The major conclusion to be drawn is that it is the total system, including satellite electronic system, photovoltaic systems, peak power tracker and the power management and distribution systems which need to be optimized. An example of a peak power tracker is given, and a novel series connected boost unit is described which might allow the system voltage to be increased if enough photovoltaic panels to operate the systems in real time is impractical. Finally, it is recommended that the development effort be oriented and expanded to include a peak power tracker and other power management and distribution systems.

In April they received a DOE Defense Programs award for significant contributions to the Nuclear Weapons Program in developing and applying z-pinch x-ray sources to stockpile stewardship. DOE also recognized pulsed power for outstanding performance at a world-class level as part of the FY98 performance appraisal review. There were 13 Z shots: 3 for LANL weapon physics, 2 to prepare to measure the D{sub 2} equation of state (EOS), 4 to assess energetics of single-sided drive with the z-pinch-driven hohlraum, and 4 to study the variation in x-ray power with the mass of a copper converter foil inside a nested wire array for the dynamic hohlraum.