Publications

Time-domain simulations of the loads on wind energy conversion systems have been hampered in the past by the relatively long computational times for nonlinear structural analysis codes. However, recent advances in both the level of sophistication and computational efficiency of available computer hardware and the codes themselves now permit long-term simulations to be conducted in reasonable times. Thus, these codes provide a unique capability to evaluate the spectral content of the fatigue loads on a turbine. To demonstrate these capabilities, a Micon 65/13 turbine is analyzed using the YawDyn and the ADAMS dynamic analysis codes. The SNLWIND-3D simulator and measured boundary conditions are used to simulate the inflow environment that can be expected during a single, 24-hour period by a turbine residing in Row 41 of a wind farm located in San Gorgonio Pass, California. Also, long-term simulations (up to 8 hours of simulated time) with constant average inflow velocities are used to better define the characteristics of the fatigue load on the turbine. Damage calculations, using the LIFE2 fatigue analysis code and the MSU/DOE fatigue data base for composite materials, are then used to determine minimum simulation times for consistent estimates of service lifetimes.

In an effort to devise a cost efficient technology for remediation of uranium contaminated groundwater, the Department of Energy`s Uranium Mill Tailings Remedial Action (DOE-UMTRA) Program through Sandia National Laboratories (SNL) fabricated a pilot scale research project utilizing reactive subsurface barriers at an UMTRA site in Durango, Colorado. A reactive subsurface barrier is produced by placing a reactant material (in this experiment, metallic iron) in the flow path of the contaminated groundwater. The reactive media then removes and/or transforms the contaminant(s) to regulatory acceptable levels. Experimental design and results are discussed with regard to other potential applications of reactive barrier remediation strategies at other sites with contaminated groundwater problems.

Ceramic samples of (La{sub 1-x}Gd{sub x}){sub 2/3}Ca{sub 1/3}MnO{sub 3} were prepared and used as targets to grow films onto LaAlO{sub 3} substrates by pulsed laser deposition. Electrical resistance and thermopower, measured vs temperature and applied magnetic fields indicate transport dominated by positive small polarons in the high temperature paramagnetic state. The Hall effect was measured in 0.5 {mu}m thick films of composition x=0 and x=0.25. No evidence for extraordinary hall effect was found in the paramagnetic regime. Instead, the magnitude of the Hall coefficient decreases exponentially with temperature. This behavior and its anomalous negative sign are interpreted to result from face-diagonal hopping of small polarons in the Mn sublattice.

Prosperity Games{trademark} are an outgrowth and adaptation of move/countermove and seminar War Games, Prosperity Games{trademark} are simulations that explore complex issues in a variety of areas including economics, politics, sociology, environment, education, and research. These issues can be examined from a variety of perspectives ranging from global, macroeconomic and geopolitical viewpoint down to the details of customer/supplier/market interactions specific industries. All Prosperity Games{trademark} are unique in that both the game format and the player contributions vary from game to game. This report documents the Future{at}Labs.Prosperity Game{trademark} conducted under the sponsorship of the Industry Advisory Boards of the national labs, the national labs, Lockheed Martin Corporation, and the University of California. Players were drawn from all stakeholders involved including government, industry, labs, and academia. The primary objectives of this game were to: (1) explore ways to optimize the role of the multidisciplinary labs in serving national missions and needs; (2) explore ways to increase collaboration and partnerships among government, laboratories, universities, and industry; and (3) create a network of partnership champions to promote findings and policy options. The deliberations and recommendations of these players provided valuable insights as to the views of this diverse group of decision makers concerning the future of the labs.

No abstract available.

A procedure is presented for developing the route characterization used to assess the risk for the highway transport of nuclear materials. The types of data needed for a risk assessment and the sources used to provide that data are discussed. An outline of the methods used to get from data source to the route characterization used for risk analysis is presented. The models and methodologies developed for this study were programmed into the ADROIT computer code, which ha become one of Sandia`s principal analysis tools for doing risk assessments for the highway transportation risk for nuclear materials.

Sandia National Laboratories operates two reactors which fall under US Environmental Protection Agency regulations for emission of radionuclides to the ambient air. These reactors are: (1) the Annular Core Research Reactor, a pool-type reactor and (2) the Sandia Pulsed Reactor III, a Godiva-type reactor. The annual radioactive air emissions from these two reactors had been estimated based on engineering calculations and used in the facility Safety Analysis Report. The calculated release rates had never been confirmed through measurements. The purpose of this work was to obtain confirmatory radioactive gas and aerosol concentration measurements for radionuclides in exhaust stacks of these reactors during normal operation; however, the measured production rate of argon-41 was significantly different from the engineering calculations for both reactors. The resolution of this difference is discussed.

SC-1 (NH{sub 4}OH/H{sub 2}O{sub 2}/H{sub 2}O) and piranha (H{sub 2}SO{sub 4}/H{sub 2}O{sub 2}) cleans have been used for many years to remove particulate and organic contamination. Although the SC-1 clean, often used with applied megasonic power, is known to be highly effective for particle removal, the removal mechanism remains unclear. For the removal of heavy organic contamination, the piranha cleaning chemistry is an effective process; however, post-piranha residue adheres tenaciously to the wafer surface, causing a particle growth phenomenon. A series of experiments have been performed to help understand the interaction of these processes with silicon surfaces.

As device critical dimensions decrease in size it becomes increasingly important to remove particles from the wafer surface so they do not impact device yield. A typical method to evaluate various cleaning techniques is to deposit silicon nitride (Si{sub 3}N{sub 4}) particles on the wafer surface and then process the wafers through the desired cleaning processes. The National Technology Roadmap for Semiconductors specifies the standard challenge for percent particle removal from silicon wafers to be based on > 1,000 nitride particles added to the wafers. However, it does not specify the deposition technique to be used for the Si{sub 3}N{sub 4} particles. Two common methods used to deposit Si{sub 3}N{sub 4} on silicon test wafers are the aerosol deposition technique or the wet dip deposition technique. A comparison between these two Si{sub 3}N{sub 4} deposition methods to determine if these methods create an equivalent particle removal challenge has not been reported in the literature to date. In this paper the authors compare these two deposition techniques. They found advantages and disadvantages for both deposition methods. The preferred method for particle deposition is dependent on the specific application.

The suitability of various metallic printed wiring board surface finishes was assessed for new technology applications that incorporate assembly with Lead-free solders. The manufacture of a lead-free product necessitates elimination of lead (Pb) from the solder, the circuit board as well as the component lead termination. It is critical however for the selected interconnect Pb-free solder and the corresponding printed wiring board (PWB) and component lead finishes to be mutually compatible. Baseline compatibility of select Pb-free solders with Pb containing PWB surface finish and components was assessed. This was followed by examining the compatibility of the commercially available CASTIN{trademark} (SnAgCuSb) Pb-free solder with a series of PWB metallic finishes: Ni/Au, Ni/Pd, and Pd/Cu. The compatibility was assessed with respect to assembly performance, solder joint integrity and long term attachment reliability. Solder joint integrity and mechanical behavior of representative 50 mil pitch 20I/O SOICs was determined before and after thermal stress. Mechanical pull test studies demonstrated that the strength of SnAgCuSb solder interconnections is notably greater than that of SnPb interconnections.

Pulsed high-energy ion beams have been used to thermally treat Ti and Ti alloy surfaces to alter the electrochemical response. Two regimes have been explored: rapid melt and resolidification, and ion beam mixing. In this report, results from initial studies are presented exploring effect of these two regimes on the electrochemical behavior of Ti and Ti alloys.

Recently, a great deal of interest has developed in manufacturing processes that allow the monolithic integration of MicroElectroMechanical Systems (MEMS) with driving, controlling, and signal processing electronics. This integration promises to improve the performance of micromechanical devices as well as lower the cost of manufacturing, packaging, and instrumenting these devices by combining the micromechanical devices with a electronic devices in the same manufacturing and packaging process. In order to maintain modularity and overcome some of the manufacturing challenges of the CMOS-first approach to integration, we have developed a MEMS-first process. This process places the micromechanical devices in a shallow trench, planarizes the wafer, and seals the micromechanical devices in the trench. Then, a high-temperature anneal is performed after the devices are embedded in the trench prior to microelectronics processing. This anneal stress-relieves the micromechanical polysilicon and ensures that the subsequent thermal processing associated with fabrication of the microelectronic processing does not adversely affect the mechanical properties of the polysilicon structures. These wafers with the completed, planarized micromechanical devices are then used as starting material for conventional CMOS processes. The circuit yield for the process has exceeded 98%. A description of the integration technology, the refinements to the technology, and wafer-scale parametric measurements of device characteristics is presented. Additionally, the performance of integrated sensing devices built using this technology is presented.

New, previously unpublished shock wave data on soda-lime glass are presented. These data are examined in light of recent experimental evidence for failure wave behavior in brittle solids. An underlying physical basis for failure waves is explored in terms of inelastic deformation kinetics processes.

An ultrasonic inspection method was developed at FAA`s Airworthiness Assurance NDI Validation Center (AANC) to easily and rapidly detect hidden fatigue cracks in the copilot vertical windshield post on USCG (Coast Guard) HU-25 `Guardian` aircraft. The inspection procedure locates hidden cracks as small as 3.2 mm emanating from internal fastener holes and determines their length. A test procedure was developed and a baseline assessment of the USCG fleet conducted. Inspection results on 41 aircraft revealed good correlation with results made during subsequent structural disassembly and visual inspection of selected aircraft.

The US-Russian Government-to-Government Program of Cooperation on Nuclear Material Protection, Control, and Accounting (MPC&A) evolved from the Nunn-Lugar Cooperative Threat Reduction Program. In 1995, the US Department of Energy (DOE) assumed responsibility as the executive agent for implementation of the Government-to-Government MPC&A Program, followed by the programmatic responsibility for funding. The Russian Program initially emphasized limited exchanges, demonstrations, and upgrades at low-enriched uranium (LEU) fuel fabrication facility at Elektrostal in 1994. The program has expanded to include upgrades at nuclear facilities across Russia, development of the Russian Methodological Training Center (RMTC) in Obninsk; and cooperation with Gosatomnadzor, the Russian Federal Nuclear Radiation and Safety Authority. This paper describes the overall program including program objectives, approach, and US-Russian participation, with an emphasis on DOE-GAN cooperation.

The rapid advancement of interconnect technology has resulted in a more engineered approach to designing and fabricating printed wiring board (PWB) surface features. Recent research at Sandia National Laboratories has demonstrated the importance of surface roughness on solder flow. This paper describes how chemical etching was used to enhance the solderability of surfaces that were normally difficult to wet. The effects of circuit geometry, etch concentration, and etching time on solder flow are discussed. Surface roughness and solder flow data are presented. The results clearly demonstrate the importance of surface roughness on the solderability of fine PWB surface mount features.

Material removal in chemical mechanical polishing (CMP) occurs by a pressure accentuated chemical attack of the surface. The polishing slurry typically consists of abrasive particles and reactive chemicals that may or may not include an oxidant. Post-CMP cleaning processes must remove both the ionic contaminants and any remaining polishing slurry particles. Central to the effectiveness of a clean is the use of conditions that will minimize the binding force between the residual particles and the wafer surface. The morphology and composition of the particle, the surface from which it must be removed, and the environment surrounding the wafer will determine the magnitude of forces that hold a particle to the wafer surface. At the Sandia/SEMATECH Center for Contamination Free Manufacturing, two techniques--atomic force microscopy (AFM) and electrokinetic deposition--are being used to explore these interactions for CMP of both oxide and tungsten surfaces. A basic understanding of particle-surface interaction forces and how they are affected by the chemical/physical environment of the particle and surface is the objective of this task. Modification of the binding forces between particles and wafer surfaces may be used to maximize post-CMP cleaning effectiveness.

A new test simulation tool is being developed to support vibration test design and to evaluate the overall testability of a component or system. This environment, the Vibration Virtual Environment for Test Optimization (VETO), is utilized to optimally place vibration control and response transducers and to investigate the selection of test parameters needed in the design and performance of a vibration experiment. The engineer can investigate the effects of different control parameters prior to performing an actual vibration test. Additionally, new and existing fixture designs can be evaluated through the development of analytical or experimental models that can be integrated into the simulation environment. This test design environment also provides the engineer with the ability to combine analytically or experimentally derived models of the vibration test hardware, instrumentation and equipment into a simulation model that represents the vibration testing capability. Hardware-in-the-loop simulations can be conducted using this model to examine multiple facets of the test design. This paper presents a new tool that will assist test engineers in maximizing the value of vibration tests through the use of hardware-in-the-loop simulations.

Experiments were performed to assess the aging degradation and loss-of-coolant accident (LOCA) behavior of electrical cables subjected to long-term aging exposures. Four different cable types were tested in both the U.S. and France: (1) U.S. 2 conductor with ethylene propylene rubber (EPR) insulation and a Hypalon jacket. (2) U.S. 3 conductor with cross-linked polyethylene (XLPE) insulation and a Hypalon jacket. (3) French 3 conductor with EPR insulation and a Hypalon jacket. (4) French coaxial with polyethylene (PE) insulation and a PE jacket. The data represent up to 5 years of simultaneous aging where the cables were exposed to identical aging radiation doses at either 40{degrees}C or 70{degrees}C; however, the dose rate used for the aging irradiation was varied over a wide range (2-100 Gy/hr). Aging was followed by exposure to simulated French LOCA conditions. Several mechanical, electrical, and physical-chemical condition monitoring techniques were used to investigate the degradation behavior of the cables. All the cables, except for the French PE cable, performed acceptably during the aging and LOCA simulations. In general, cable degradation at a given dose was highest for the lowest dose rate, and the amount of degradation decreased as the dose rate was increased.

The Korean peninsula is the site of a tense military confrontation. Relations between North and South Korea improved during the early 1990`s but the process is now frozen. Confidence building measures, particularly military ones, that address the security needs of both countries would decrease the danger of conflict and help create an environment for direct negotiations. The Korean Institute for Defense Analysis (KIDA) analyzed current security conditions and options. Their scenario includes a conceptual agreement to establish Limited Force Deployment Zones (LDZ) along the current demilitarized zone (DMZ) to increase mutual security. The Cooperative Monitoring Center (CMC) of Sandia National Laboratories, in collaboration with KIDA, developed a strategy, with examples, for cooperatively monitoring the agreement. A cooperative monitoring regime requires consideration of the agreement`s terms, the geographic, logistic, military, and political factors of the Korean environment, and the capability of technology to monitor the terms. This paper assesses the applicability of cooperative monitoring to Korea, describes the monitoring strategy for the Korean enhanced DMZ scenario, and describes the applicable technologies and procedures.

We present growth and characterization of visible and near-infrared vertical-cavity surface emitting lasers (VCSELs) grown by metalorganic vapor phase epitaxy. Discussions on the growth issue of VCSEL materials include growth rate and composition control using an {ital in}{ital situ} normal-incidence reflectometer, comprehensive p- and n-type doping study in AlGaAs by CCl{sub 4} and Si{sub 2}H{sub 6} over the entire composition range, and optimization of ultra-high material uniformity. We also demonstrate our recent achievements of all-AlGaAs VCSELs which include the first room-temperature continuous- wave demonstration of 700-nm red VCSELs and high-efficiency and low- threshold voltage 850-nm VCSELs.

The DOE/DOD Environmental Data Bank was established in 1959 as a central location for storing weapons and equipment environments information from a variety of DOE, DoD, and industrial sources and continues to be maintained by Sandia National Laboratories. The Data Bank contains approximately 3,000 documents regarding normal and abnormal environments that describe handling, storage, transportation, use, and general phases, which occur during the life of a system. This paper describes the DOE/DOD Environmental Data Bank system, its structure, data sources, usage, and progress in converting it from a microfilm database to an electronic database.

It is common practice in applied mechanics to develop mathematical models for mechanical system behavior. Frequently, the actual physical system being modeled is also available for testing, and sometimes the test data are used to help identify the parameters of the mathematical model. However, no general-purpose technique exists for formally, statistically judging the quality of a model. This paper suggests a formal statistical procedure for the validation of mathematical models of physical systems when data taken during operation of the physical system are available. The statistical validation procedure is based on the bootstrap, and it seeks to build a framework where a statistical test of hypothesis can be run to determine whether or not a mathematical model is an acceptable model of a physical system with regard to user-specified measures of system behavior. The approach to model validation developed in this study uses experimental data to estimate the marginal and joint confidence intervals of statistics of interest of the physical system. These same measures of behavior are estimated for the mathematical model. The statistics of interest from the mathematical model are located relative to the confidence intervals for the statistics obtained from the experimental data. These relative locations are used to judge the accuracy of the mathematical model. A numerical example is presented to demonstrate the application of the technique.

A comparison is provided of the results of various methods for evaluating structure during a ship-to-ship collision. The baseline vessel utilized in the analyses is a 67.4 meter in length displacement hull struck by an identical vessel traveling at speeds ranging from 10 to 30 knots. The structural response of the struck vessel and motion of both the struck and striking vessels are assessed by finite element analysis. These same results are then compared to predictions utilizing the {open_quotes}Tanker Structural Analysis for Minor Collisions{close_quotes} (TSAMC) Method, the Minorsky Method, the Haywood Collision Process, and comparison to full-scale tests. Consideration is given to the nature of structural deformation, absorbed energy, penetration, rigid body motion, and virtual mass affecting the hydrodynamic response. Insights are provided with regard to the calibration of the finite element model which was achievable through utilizing the more empirical analyses and the extent to which the finite element analysis is able to simulate the entire collision event. 7 refs., 8 figs., 4 tabs.

The objective of this project was to determine the savings in utility operating costs that could be obtained by installing a Battery Energy Storage System (BESS). The target utility was Kansas City Power and Light (KCPL), a typical Midwestern utility with a mix of generating plants and many interconnections. The following applications of battery energy storage were modeled using an Electric Power Research Institute (EPRI) developed and supported program called DYNASTORE: (1) Spinning Reserve Only (2) Load Leveling with Spinning Reserve (3) Load Leveling Only (4) Frequency Control DYNASTORE commits energy storage units along with generating units and calculates operating costs with and without energy storage, so that savings can be estimated. Typical weeks of hourly load data are used to make up a yearly load profile. For this study, the BESS power ranged from ``small`` to 300 MW (greater than the spinning reserve requirement). BESS storage time ranged from 1 to 8 hours duration (to cover the time-width of most peaks). Savings in operating costs were calculated for each of many sizes of MW capacity and duration. Graphs were plotted to enable the reader to readily see what size of BESS affords the greatest savings in operating costs.