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Temporally shaped current pulses on a two-cavity linear transformer driver system

Digest of Technical Papers-IEEE International Pulsed Power Conference

Savage, Mark E.; Mazarakis, Michael G.; LeChien, K.R.; Stoltzfus, Brian; Stygar, William A.; Fowler, William E.; Madrid, E.A.; Miller, C.L.; Rose, D.V.

An important application for low impedance pulsed power drivers is creating high pressures for shock compression of solids. These experiments are useful for studying material properties under kilobar to megabar pressures. The Z driver at Sandia National Laboratories has been used for such studies on a variety of materials, including heavy water, diamond, and tantalum, to name a few. In such experiments, it is important to prevent shock formation in the material samples. Shocks can form as the sound speed increases with loading; at some depth in the sample a pressure significantly higher than the surface pressure can result. The optimum pressure pulse shape to prevent such shocks depends on the test material and the sample thickness, and is generally not a simple sinusoidal-shaped current as a function of time. A system that can create a variety of pulse shapes would be desirable for testing various materials and sample thicknesses. A large number of relatively fast pulses, combined, could create the widest variety of pulse shapes. Linear transformer driver systems, whose cavities consist of many parallel capacitor-switch circuits, could have considerable agility in pulse shape. © 2011 IEEE.

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Best-effort authentication for opportunistic networks

Conference Proceedings of the IEEE International Performance, Computing, and Communications Conference

Solis, John H.; Ginzboorg, Philip; Asokan, N.; Ott, Jörg

A "best-effort" authentication method, which is easier to attack than generic authentication methods (but requires fewer computations for benign nodes), may be sufficient for certain networking scenarios. We illustrate this point by examining the case of fragment authentication by intermediaries in an opportunistic network. We describe mechanisms for implementing best-effort authentication, with the caveat that an authentication strength sufficient in one scenario may be unfit for another. © 2011 IEEE.

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LNG Cascading Damage Study Volume I: Fracture Testing Report

Kalan, Robert J.; Petti, Jason P.

As part of the liquefied natural gas (LNG) Cascading Damage Study, a series of structural tests were conducted to investigate the thermal induced fracture of steel plate structures. The thermal stresses were achieved by applying liquid nitrogen (LN2) onto sections of each steel plate. In addition to inducing large thermal stresses, the lowering of the steel temperature simultaneously reduced the fracture toughness. Liquid nitrogen was used as a surrogate for LNG due to safety concerns and since the temperature of LN2 is similar (-190°C) to LNG (-161°C). The use of LN2 ensured that the tests could achieve cryogenic temperatures in the range an actual vessel would encounter during a LNG spill. There were four phases to this test series. Phase I was the initial exploratory stage, which was used to develop the testing process. In the Phase II series of tests, larger plates were used and tested until fracture. The plate sizes ranged from 4 ft square pieces to 6 ft square sections with thicknesses from ¼ inches to ¾ inches. This phase investigated the cooling rates on larger plates and the effect of different notch geometries (stress concentrations used to initiate brittle fracture). Phase II was divided into two sections, Phase II-A and Phase II-B. Phase II-A used standard A36 steel, while Phase II-B used marine grade steels. In Phase III, the test structures were significantly larger, in the range of 12 ft by 12 ft by 3 ft high. These structures were designed with more complex geometries to include features similar to those on LNG vessels. The final test phase, Phase IV, investigated differences in the heat transfer (cooling rates) between LNG and LN2. All of the tests conducted in this study are used in subsequent parts of the LNG Cascading Damage Study, specifically the computational analyses.

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Including shielding effects in application of the TPCA method for detection of embedded radiation sources

Shokair, Isaac R.; Johnson, William C.

Conventional full spectrum gamma spectroscopic analysis has the objective of quantitative identification of all the radionuclides present in a measurement. For low-energy resolution detectors such as NaI, when photopeaks alone are not sufficient for complete isotopic identification, such analysis requires template spectra for all the radionuclides present in the measurement. When many radionuclides are present it is difficult to make the correct identification and this process often requires many attempts to obtain a statistically valid solution by highly skilled spectroscopists. A previous report investigated using the targeted principal component analysis method (TPCA) for detection of embedded sources for RPM applications. This method uses spatial/temporal information from multiple spectral measurements to test the hypothesis of the presence of a target spectrum of interest in these measurements without the need to identify all the other radionuclides present. The previous analysis showed that the TPCA method has significant potential for automated detection of target radionuclides of interest, but did not include the effects of shielding. This report complements the previous analysis by including the effects of spectral distortion due to shielding effects for the same problem of detection of embedded sources. Two examples, one with one target radionuclide and the other with two, show that the TPCA method can successfully detect shielded targets in the presence of many other radionuclides. The shielding parameters are determined as part of the optimization process using interpolation of library spectra that are defined on a 2D grid of atomic numbers and areal densities.

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Moore’s Law And The Impact On Trusted And Radiation-Hardened Microelectronics

Ma, Kwok-Kee

In 1965 Gordon Moore wrote an article claiming that integrated circuit density would scale exponentially. His prediction has remained valid for more than four decades. Integrated circuits have changed all aspects of everyday life. They are also the 'heart and soul' of modern systems for defense, national infrastructure, and intelligence applications. The United States government needs an assured and trusted microelectronics supply for military systems. However, migration of microelectronics design and manufacturing from the United States to other countries in recent years has placed the supply of trusted microelectronics in jeopardy. Prevailing wisdom dictates that it is necessary to use microelectronics fabricated in a state-of-the-art technology for highest performance and military system superiority. Close examination of silicon microelectronics technology evolution and Moore's Law reveals that this prevailing wisdom is not necessarily true. This presents the US government the possibility of a totally new approach to acquire trusted microelectronics.

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Pollution prevention opportunity assessment for MicroFab and SiFab facilities at Sandia National Laboratories

Gerard, Morgan E.

This Pollution Prevention Opportunity Assessment (PPOA) was conducted for the MicroFab and SiFab facilities at Sandia National Laboratories/New Mexico in Fiscal Year 2011. The primary purpose of this PPOA is to provide recommendations to assist organizations in reducing the generation of waste and improving the efficiency of their processes and procedures. This report contains a summary of the information collected, the analyses performed, and recommended options for implementation. The Sandia National Laboratories Environmental Management System (EMS) and Pollution Prevention (P2) staff will continue to work with the organizations to implement the recommendations.

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Dynamic reactor modeling with applications to SPR and ZEDNA

Suo-Anttila, Ahti J.

A dynamic reactor model has been developed for pulse-type reactor applications. The model predicts reactor power, axial and radial fuel expansion, prompt and delayed neutron population, and prompt and delayed gamma population. All model predictions are made as a function of time. The model includes the reactivity effect of fuel expansion on a dynamic timescale as a feedback mechanism for reactor power. All inputs to the model are calculated from first principles, either directly by solving systems of equations, or indirectly from Monte Carlo N-Particle Transport Code (MCNP) derived results. The model does not include any empirical parameters that can be adjusted to match experimental data. Comparisons of model predictions to actual Sandia Pulse Reactor SPR-III pulses show very good agreement for a full range of pulse magnitudes. The model is also applied to Z-pinch externally driven neutron assembly (ZEDNA) type reactor designs to model both normal and off-normal ZEDNA operations.

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Science-based Solutions to Achieve High-performance Deep-UV Laser Diodes (Final LDRD Report)

Crawford, Mary H.; Allerman, A.A.; Armstrong, Andrew A.; Miller, Mary A.; Smith, Michael L.; Cross, Karen C.; Lee, Stephen R.; Henry, Tania A.; Alessi, Leonard J.

We present the results of a three year LDRD project that has focused on overcoming major materials roadblocks to achieving AlGaN-based deep-UV laser diodes. We describe our growth approach to achieving AlGaN templates with greater than ten times reduction of threading dislocations which resulted in greater than seven times enhancement of AlGaN quantum well photoluminescence and 15 times increase in electroluminescence from LED test structures. We describe the application of deep-level optical spectroscopy to AlGaN epilayers to quantify deep level energies and densities and further correlate defect properties with AlGaN luminescence efficiency. We further review our development of p-type short period superlattice structures as an approach to mitigate the high acceptor activation energies in AlGaN alloys. Finally, we describe our laser diode fabrication process, highlighting the development of highly vertical and smooth etched laser facets, as well as characterization of resulting laser heterostructures.

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Structural Considerations for Solar Installers: An approach for small, simplified solar installations or retrofits

Dwyer, Stephen F.; Bosiljevac, Thomas B.; Richards, Elizabeth H.

Structural Considerations for Solar Installers provides a comprehensive outline of structural considerations associated with simplified solar installations and recommends a set of best practices installers can follow when assessing such considerations. Information in the manual comes from engineering and solar experts as well as case studies. The objectives of the manual are to ensure safety and structural durability for rooftop solar installations and to potentially accelerate the permitting process by identifying and remedying structural issues prior to installation. The purpose of this document is to provide tools and guidelines for installers to help ensure that residential photovoltaic (PV) power systems are properly specified and installed with respect to the continuing structural integrity of the building.

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Microkinetic Modeling of Lean NOx Trap Storage and Regeneration

Larson, Richard S.

A microkinetic chemical reaction mechanism capable of describing both the storage and regeneration processes in a fully formulated lean NOx trap (LNT) is presented. The mechanism includes steps occurring on the precious metal, barium oxide (NOx storage), and cerium oxide (oxygen storage) sites of the catalyst. The complete reaction set is used in conjunction with a transient plug flow reactor code (including boundary layer mass transfer) to simulate not only a set of long storage/regeneration cycles with a CO/H2 reductant, but also a series of steady flow temperature sweep experiments that were previously analyzed with just a precious metal mechanism and a steady state code neglecting mass transfer. The results show that, while mass transfer effects are generally minor, NOx storage is not negligible during some of the temperature ramps, necessitating a re-evaluation of the precious metal kinetic parameters. The parameters for the entire mechanism are inferred by finding the best overall fit to the complete set of experiments. Rigorous thermodynamic consistency is enforced for parallel reaction pathways and with respect to known data for all of the gas phase species involved. It is found that, with a few minor exceptions, all of the basic experimental observations can be reproduced with the transient simulations. In addition to accounting for normal cycling behavior, the final mechanism should provide a starting point for the description of further LNT phenomena such as desulfation and the role of alternative reductants.

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Analysis of sheltering and evacuation strategies for a national capital region nuclear detonation scenario

Brandt, Larry D.; Yoshimura, Ann S.

Development of an effective strategy for shelter and evacuation is among the most important planning tasks in preparation for response to a low yield, nuclear detonation in an urban area. Extensive studies have been performed and guidance published that highlight the key principles for saving lives following such an event. However, region-specific data are important in the planning process as well. This study examines some of the unique regional factors that impact planning for a 10 kT detonation in the National Capital Region. The work utilizes a single scenario to examine regional impacts as well as the shelter-evacuate decision alternatives at one exemplary point. For most Washington, DC neighborhoods, the excellent assessed shelter quality available make shelter-in-place or selective transit to a nearby shelter a compelling post-detonation strategy.

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DAKOTA : a multilevel parallel object-oriented framework for design optimization, parameter estimation, uncertainty quantification, and sensitivity analysis

Adams, Brian M.; Bohnhoff, William J.; Dalbey, Keith; Eddy, John P.; Eldred, Michael; Hough, Patricia D.; Lefantzi, Sophia; Swiler, Laura P.; Vigil, Dena

The DAKOTA (Design Analysis Kit for Optimization and Terascale Applications) toolkit provides a flexible and extensible interface between simulation codes and iterative analysis methods. DAKOTA contains algorithms for optimization with gradient and nongradient-based methods; uncertainty quantification with sampling, reliability, and stochastic expansion methods; parameter estimation with nonlinear least squares methods; and sensitivity/variance analysis with design of experiments and parameter study methods. These capabilities may be used on their own or as components within advanced strategies such as surrogate-based optimization, mixed integer nonlinear programming, or optimization under uncertainty. By employing object-oriented design to implement abstractions of the key components required for iterative systems analyses, the DAKOTA toolkit provides a flexible and extensible problem-solving environment for design and performance analysis of computational models on high performance computers. This report serves as a theoretical manual for selected algorithms implemented within the DAKOTA software. It is not intended as a comprehensive theoretical treatment, since a number of existing texts cover general optimization theory, statistical analysis, and other introductory topics. Rather, this manual is intended to summarize a set of DAKOTA-related research publications in the areas of surrogate-based optimization, uncertainty quantification, and optimization under uncertainty that provide the foundation for many of DAKOTA's iterative analysis capabilities.

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Verification of the Coupled Fluid/Solid Transfer in a CASL Grid-to-Rod-Fretting Simulation: A Technical Brief on the Analysis of Convergence Behavior and Demonstration of Software Tools for Verification

Copps, Kevin D.

For a CASL grid-to-rod fretting problem, Sandia's Percept software was used in conjunction with the Sierra Mechanics suite to analyze the convergence behavior of the data transfer from a fluid simulation to a solid mechanics simulation. An analytic function, with properties relatively close to numerically computed fluid approximations, was chosen to represent the pressure solution in the fluid domain. The analytic pressure was interpolated on a sequence of grids on the fluid domain, and transferred onto a separate sequence of grids in the solid domain. The error in the resulting pressure in the solid domain was measured with respect to the analytic pressure. The error in pressure approached zero as both the fluid and solids meshes were refined. The convergence of the transfer algorithm was limited by whether the source grid resolution was the same or finer than the target grid resolution. In addition, using a feature coverage analysis, we found gaps in the solid mechanics code verification test suite directly relevant to the prototype CASL GTRF simulations.

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Biomolecular Interactions and Responses of Human Epithelial and Macrophage Cells to Engineered Nanomaterials

Bachand, George D.; Brozik, Susan M.; Bachand, Marlene; Aaron, Jesse S.; Timlin, Jerilyn A.; Achyuthan, Komandoor; Kotula, Paul G.

Engineered nanomaterials (ENMs) are increasingly being used in commercial products, particularly in the biomedical, cosmetic, and clothing industries. For example, pants and shirts are routinely manufactured with silver nanoparticles to render them 'wrinkle-free.' Despite the growing applications, the associated environmental health and safety (EHS) impacts are completely unknown. The significance of this problem became pervasive within the general public when Prince Charles authored an article in 2004 warning of the potential social, ethical, health, and environmental issues connected to nanotechnology. The EHS concerns, however, continued to receive relatively little consideration from federal agencies as compared with large investments in basic nanoscience R&D. The mounting literature regarding the toxicology of ENMs (e.g., the ability of inhaled nanoparticles to cross the blood-brain barrier; Kwon et al., 2008, J. Occup. Health 50, 1) has spurred a recent realization within the NNI and other federal agencies that the EHS impacts related to nanotechnology must be addressed now. In our study we proposed to address critical aspects of this problem by developing primary correlations between nanoparticle properties and their effects on cell health and toxicity. A critical challenge embodied within this problem arises from the ability to synthesize nanoparticles with a wide array of physical properties (e.g., size, shape, composition, surface chemistry, etc.), which in turn creates an immense, multidimensional problem in assessing toxicological effects. In this work we first investigated varying sizes of quantum dots (Qdots) and their ability to cross cell membranes based on their aspect ratio utilizing hyperspectral confocal fluorescence microscopy. We then studied toxicity of epithelial cell lines that were exposed to different sized gold and silver nanoparticles using advanced imaging techniques, biochemical analyses, and optical and mass spectrometry methods. Finally we evaluated a new assay to measure transglutaminase (TG) activity; a potential marker for cell toxicity.

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Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC): Subcontinuum-scale Verification and Validation Strategy

Schultz, Peter A.

The objective of the U.S. Department of Energy Office of Nuclear Energy Advanced Modeling and Simulation Waste Integrated Performance and Safety Codes (NEAMS Waste IPSC) is to provide an integrated suite of computational modeling and simulation (M&S) capabilities to quantitatively assess the long-term performance of waste forms in the engineered and geologic environments of a radioactive-waste storage facility or disposal repository. Achieving the objective of modeling the performance of a disposal scenario requires describing processes involved in waste form degradation and radionuclide release at the subcontinuum scale, beginning with mechanistic descriptions of chemical reactions and chemical kinetics at the atomic scale, and upscaling into effective, validated constitutive models for input to high-fidelity continuum scale codes for coupled multiphysics simulations of release and transport. Verification and validation (V&V) is required throughout the system to establish evidence-based metrics for the level of confidence in M&S codes and capabilities, including at the subcontiunuum scale and the constitutive models they inform or generate. This Report outlines the nature of the V&V challenge at the subcontinuum scale, an approach to incorporate V&V concepts into subcontinuum scale modeling and simulation (M&S), and a plan to incrementally incorporate effective V&V into subcontinuum scale M&S destined for use in the NEAMS Waste IPSC work flow to meet requirements of quantitative confidence in the constitutive models informed by subcontinuum scale phenomena.

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Technical Cooperation on Nuclear Security between the United States and China: Review of the Past and Opportunities for the Future

Pregenzer, Arian L.

The United States and China are committed to cooperation to address the challenges of the next century. Technical cooperation, building on a long tradition of technical exchange between the two countries, can play an important role. This paper focuses on technical cooperation between the United States and China in the areas of nonproliferation, arms control and other nuclear security topics. It reviews cooperation during the 1990s on nonproliferation and arms control under the U.S.-China Arms Control Exchange, discusses examples of ongoing activities under the Peaceful Uses of Technology Agreement to enhance security of nuclear and radiological material, and suggests opportunities for expanding technical cooperation between the defense nuclear laboratories of both countries to address a broader range of nuclear security topics.

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Reference Model MHK Turbine Array Optimization Study within a Generic River System

Johnson, Erick; Barco Mugg, Janet; James, Scott; Roberts, Jesse D.

Increasing interest in marine hydrokinetic (MHK) energy has spurred to significant research on optimal placement of emerging technologies to maximize energy conversion and minimize potential effects on the environment. However, these devices will be deployed as an array in order to reduce the cost of energy and little work has been done to understand the impact these arrays will have on the flow dynamics, sediment-bed transport and benthic habitats and how best to optimize these arrays for both performance and environmental considerations. An "MHK-friendly" routine has been developed and implemented by Sandia National Laboratories (SNL) into the flow, sediment dynamics and water-quality code, SNL-EFDC. This routine has been verified and validated against three separate sets of experimental data. With SNL-EFDC, water quality and array optimization studies can be carried out to optimize an MHK array in a resource and study its effects on the environment. The present study examines the effect streamwise and spanwise spacing has on the array performance. Various hypothetical MHK array configurations are simulated within a trapezoidal river channel. Results show a non-linear increase in array-power efficiency as turbine spacing is increased in each direction, which matches the trends seen experimentally. While the sediment transport routines were not used in these simulations, the flow acceleration seen around the MHK arrays has the potential to significantly affect the sediment transport characteristics and benthic habitat of a resource. Evaluation Only. Created with Aspose.Pdf.Kit. Copyright 2002-2011 Aspose Pty Ltd Evaluation Only. Created with Aspose.Pdf.Kit. Copyright 2002-2011 Aspose Pty Ltd

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Reference Model 2: "Rev 0" Rotor Design

Barone, Matthew F.; Berg, Jonathan C.; Griffith, Daniel

The preliminary design for a three-bladed cross-flow rotor for a reference marine hydrokinetic turbine is presented. A rotor performance design code is described, along with modifications to the code to allow prediction of blade support strut drag as well as interference between two counter-rotating rotors. The rotor is designed to operate in a reference site corresponding to a riverine environment. Basic rotor performance and rigid-body loads calculations are performed to size the rotor elements and select the operating speed range. The preliminary design is verified with a simple finite element model that provides estimates of bending stresses during operation. A concept for joining the blades and support struts is developed and analyzed with a separate finite element analysis. Rotor mass, production costs, and annual energy capture are estimated in order to allow calculations of system cost-of-energy. Evaluation Only. Created with Aspose.Pdf.Kit. Copyright 2002-2011 Aspose Pty Ltd Evaluation Only. Created with Aspose.Pdf.Kit. Copyright 2002-2011 Aspose Pty Ltd

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An Economic Analysis of Mobile Pyrolysis for Northern New Mexico Forests

Brown, Alexander L.; Mowry, Curtis D.; Borek, Theodore T.

In the interest of providing an economically sensible use for the copious small-diameter wood in Northern New Mexico, an economic study is performed focused on mobile pyrolysis. Mobile pyrolysis was selected for the study because transportation costs limit the viability of a dedicated pyrolysis plant, and the relative simplicity of pyrolysis compared to other technology solutions lends itself to mobile reactor design. A bench-scale pyrolysis system was used to study the wood pyrolysis process and to obtain performance data that was otherwise unavailable under conditions theorized to be optimal given the regional problem. Pyrolysis can convert wood to three main products: fixed gases, liquid pyrolysis oil and char. The fixed gases are useful as low-quality fuel, and may have sufficient chemical energy to power a mobile system, eliminating the need for an external power source. The majority of the energy content of the pyrolysis gas is associated with carbon monoxide, followed by light hydrocarbons. The liquids are well characterized in the historical literature, and have slightly lower heating values comparable to the feedstock. They consist of water and a mix of hundreds of hydrocarbons, and are acidic. They are also unstable, increasing in viscosity with time stored. Up to 60% of the biomass in bench-scale testing was converted to liquids. Lower (~550°C) furnace temperatures are preferred because of the decreased propensity for deposits and the high liquid yields. A mobile pyrolysis system would be designed with low maintenance requirements, should be able to access wilderness areas, and should not require more than one or two people to operate the system. The techno-economic analysis assesses fixed and variable costs. It suggests that the economy of scale is an important factor, as higher throughput directly leads to improved system economic viability. Labor and capital equipment are the driving factors in the viability of the system. The break-even selling price for the baseline assumption is about $\$$11/GJ, however it may be possible to reduce this value by 20-30% depending on other factors evaluated in the non-baseline scenarios. Assuming a value for the char co-product improves the analysis. Significantly lower break-even costs are possible in an international setting, as labor is the dominant production cost.

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An Evaluation of Possible Next-Generation High Temperature Molten-Salt Power Towers

Kolb, Gregory J.

Since completion of the Solar Two molten-salt power tower demonstration in 1999, the solar industry has been developing initial commercial-scale projects that are 3 to 14 times larger. Like Solar Two, these initial plants will power subcritical steam-Rankine cycles using molten salt with a temperature of 565 °C. The main question explored in this study is whether there is significant economic benefit to develop future molten-salt plants that operate at a higher receiver outlet temperature. Higher temperatures would allow the use of supercritical steam cycles that achieve an improved efficiency relative to today's subcritical cycle (~50% versus ~42%). The levelized cost of electricity (LCOE) of a 565 °C subcritical baseline plant was compared with possible future-generation plants that operate at 600 or 650 °C. The analysis suggests that ~8% reduction in LCOE can be expected by raising salt temperature to 650 °C. However, most of that benefit can be achieved by raising the temperature to only 600 °C. Several other important insights regarding possible next-generation power towers were also drawn: (1) the evaluation of receiver-tube materials that are capable of higher fluxes and temperatures, (2) suggested plant reliability improvements based on a detailed evaluation of the Solar Two experience, and (3) a thorough evaluation of analysis uncertainties.

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Numerical study of a matrix-free trust-region SQP method for equality constrained optimization

Ridzal, Denis; Valentin, Miguel A.

This is a companion publication to the paper 'A Matrix-Free Trust-Region SQP Algorithm for Equality Constrained Optimization' in which we develop and analyze a trust-region sequential quadratic programming (SQP) method that supports the matrix-free (iterative, in-exact) solution of linear systems. In this report, we document the numerical behavior of the algorithm applied to a variety of equality constrained optimization problems, with constraints given by partial differential equations (PDEs).

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Recommendations on the Prediction of Thermal Hazard Distances from Large Liquefied Natural Gas Pool Fires on Water for Solid Flame Models

Luketa, Anay

The objective of this work is to provide recommendations on predicting thermal hazard distances resulting from large liquefied natural gas (LNG) pool fires on water. The recommendations pertain to an integral model approach and its pertinent parameters such as burn rate, flame height, surface emissive power (SEP), and transmissivity. These recommendations are based upon knowledge gained from conducting experiments of LNG pool fires on water at Sandia National Laboratories in New Mexico in 2009 in addition to earlier, smaller scale tests. The 83 diameter meter test resulted in a 56 m diameter pool fire which is the largest LNG pool fire test performed on water or land to date.

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Optimization of CPAPR for x64 multicore

Allan, Benjamin A.

I report the progress to date of my work on scaling the CPAPR algorithm and necessary supporting code to enable processing large (gigabyte to 100 gigabyte) data sets and benchmarking the same. Where possible, I also report background information possibly of relevance in future modifications of the code. The results include: minor repairs and additions to the TTB library for portability, algorithmic improvements relevant to both serial and multithreaded implementations, algorithmic improvements taking advantage of multithreading hardware, support library additions (binary IO routines) needed for efficiently and reproducibly benchmarking the algorithms. For this optimization work, no large scale data sets are available. Therefore, scalability of data synthesis algorithms is addressed as well.

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CASL L1 Milestone Report: CASL.P4.01, Sensitivity and Uncertainty Analysis for CIPS with VIPRE-W and BOA

Adams, Brian M.

The CASL Level 1 Milestone CASL.P4.01, successfully completed in December 2011, aimed to 'conduct, using methodologies integrated into VERA, a detailed sensitivity analysis and uncertainty quantification of a crud-relevant problem with baseline VERA capabilities (ANC/VIPRE-W/BOA).' The VUQ focus area led this effort, in partnership with AMA, and with support from VRI. DAKOTA was coupled to existing VIPRE-W thermal-hydraulics and BOA crud/boron deposit simulations representing a pressurized water reactor (PWR) that previously experienced crud-induced power shift (CIPS). This work supports understanding of CIPS by exploring the sensitivity and uncertainty in BOA outputs with respect to uncertain operating and model parameters. This report summarizes work coupling the software tools, characterizing uncertainties, and analyzing the results of iterative sensitivity and uncertainty studies. These studies focused on sensitivity and uncertainty of CIPS indicators calculated by the current version of the BOA code used in the industry. Challenges with this kind of analysis are identified to inform follow-on research goals and VERA development targeting crud-related challenge problems.

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Systems Resilience: A New Analytical Framework for Nuclear Nonproliferation

Pregenzer, Arian L.

This paper introduces the concept of systems resilience as a new framework for thinking about the future of nonproliferation. Resilience refers to the ability of a system to maintain its vital functions in the face of continuous and unpredictable change. The nonproliferation regime can be viewed as a complex system, and key themes from the literature on systems resilience can be applied to the nonproliferation system. Most existing nonproliferation strategies are aimed at stability rather than resilience, and the current nonproliferation system may be over-constrained by the cumulative evolution of strategies, increasing its vulnerability to collapse. The resilience of the nonproliferation system can be enhanced by diversifying nonproliferation strategies to include general international capabilities to respond to proliferation and focusing more attention on reducing the motivation to acquire nuclear weapons in the first place. Ideas for future research, include understanding unintended consequences and feedbacks among nonproliferation strategies, developing methodologies for measuring the resilience of the nonproliferation system, and accounting for interactions of the nonproliferation system with other systems on larger and smaller scales.

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Demand Response Pilot Event Conducted August 25, 2011 (Summary Report)

Evans, Christopher A.

Energy management in a commercial facility can be segregated into two areas: energy efficiency and demand response (DR). Energy efficiency focuses on steady-state load minimization. Demand response reduces load for event driven periods during the peak load. Demand-response-driven changes in electricity use are designed to be short-term in nature, centered on critical hours during the day when demand is high or when the electricity supplier's reserve margins are low. Due to the recent Federal Energy Regulatory Commission (FERC) Order 745, Demand Response Compensation in Organized Wholesale Energy Markets the potential annual compensation to Sandia National Laboratories (SNL) from performing DR ranges from $\$$300K to $\$$2,400K. While the current energy supply contract does not offer any compensation for participating in DR, there is benefit in understanding the issues and potential value in performing a DR event. This Report will be helpful in upcoming energy supply contract negotiations to quantify the energy savings and power reduction potential from DR at SNL. On August 25, 2011 the Facilities Management and Operations Center (FMOC) performed the first DR pilot event at SNL/NM. This report describes the details and results of this DR event.

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Empirical battery model characterizing a utility-scale carbon-enhanced VRLA battery

IEEE Energy Conversion Congress and Exposition: Energy Conversion Innovation for a Clean Energy Future, ECCE 2011, Proceedings

Fregosi, Daniel; Bhattacharya, Subhashish; Atcitty, Stanley

In this paper, the electrical characteristics of a carbon enhanced valve-regulated lead-acid (VRLA) battery from East Penn Manufacturing are investigated and a dynamic model is developed for use in electrical simulations. The electrochemical processes that cause specific dynamic behaviors have been investigated. These processes are explained and a non-linear electric model, which captures the results of some of these electrochemical dynamics, is presented. The method to determine model parameters using experimental data is shown. To verify the battery model, both a pulsed current profile and an arbitrary current profile were applied to the battery and to the battery model and the voltage responses of the two were compared. © 2011 IEEE.

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Branching fractions of the CN + C 3H 6 reaction using synchrotron photoionization mass spectrometry: Evidence for the 3-cyanopropene product

Journal of Physical Chemistry A

Trevitt, Adam J.; Soorkia, Satchin; Savee, John D.; Selby, Talitha S.; Osborn, David L.; Taatjes, Craig A.; Leone, Stephen R.

The gas-phase CN + propene reaction is investigated using synchrotron photoionization mass spectrometry (SPIMS) over the 9.8 - 11.5 eV photon energy range. Experiments are conducted at room temperature in 4 Torr of He buffer gas. The CN + propene addition reaction produces two distinct product mass channels, C 3H 3N and C 4H 5N, corresponding to CH 3 and H elimination, respectively. The CH 3 and H elimination channels are measured to have branching fractions of 0.59 ± 0.15 and 0.41 ± 0.10, respectively. The absolute photoionization cross sections between 9.8 and 11.5 eV are measured for the three considered H-elimination coproducts: 1-, 2-, and 3-cyanopropene. Based on fits using the experimentally measured photoionization spectra for the C 4H 5N mass channel and contrary to the previous study (Int. J. Mass. Spectrom.2009, 280, 113 - 118), where it was concluded that 3-cyanopropene was not a significant product, the new data suggests 3-cyanopropene is produced in significant quantity along with 1-cyanopropene, with isomer branching fractions from this mass channel of 0.50 ± 0.12 and 0.50 ± 0.24, respectively. However, similarities between the 1-, 2-, and 3-cyanopropene photoionization spectra make an unequivocal assignment difficult based solely on photoionization spectra. The CN + CH 2CHCD 3 reaction is studied and shows, in addition to the H-elimination product signal, a D-elimination product channel (m/z 69, consistent with CH 2CHCD 2CN), providing further evidence for the formation of the 3-cyanopropene reaction product. © 2011 American Chemical Society.

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Thermal infrared plasmonics

2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011

Kekatpure, Rohan D.; Peters, David; Shaner, Eric A.

We examine a new class of infrared (IR) plasmonic devices that convert thermal radiation into bound surface plasmon polaritons (SPP's). The coupling of these SPP's into nanometer scale metal insulator metal (MIM) channels is investigated both theoretically and experimentally. A new mechanism for detection of the IR radiation is examined that is based on direct rectification of a traveling MIM surface plasmon mode. © 2011 IEEE.

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CHALLENGES IN PARALLEL GRAPH PROCESSING

Parallel Processing Letters

Hendrickson, Bruce A.; Berry, Jonathan

Graph algorithms are becoming increasingly important for solving many problems in scientific computing, data mining and other domains. As these problems grow in scale, parallel computing resources are required to meet their computational and memory requirements. Unfortunately, the algorithms, software, and hardware that have worked well for developing mainstream parallel scientific applications are not necessarily effective for large-scale graph problems. In this paper we present the inter-relationships between graph problems, software, and parallel hardware in the current state of the art and discuss how those issues present inherent challenges in solving large-scale graph problems. The range of these challenges suggests a research agenda for the development of scalable high-performance software for graph problems.

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Thermodynamic analysis of solid-liquid phase equilibria of nitrate salts

Industrial and Engineering Chemistry Research

Davison, Scott M.; Sun, Amy C.

In this work, we analyze solid-liquid phase equilibria of molten nitrate salt mixtures. Molten salts are used as heat transfer fluids within concentrated solar power systems. Further understanding of the thermophysical properties of the salt solutions is integral to designing the newest generation of solar power systems. We make use of classical thermodynamics to quickly model the phase equilibrium of mixtures of nitrate salts. This modeling work can serve as a complement to existing experimental efforts in identifying appropriate multicomponent salt mixtures for solar power applications. We present phase calculations of ternary and quaternary mixtures of LiNO3, NaNO 3, KNO3, and CsNO3 modeled using the Wilson equation for liquid phase activity coefficients and binary solid-liquid equilibrium data. © 2011 American Chemical Society.

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EDO: Improving read performance for scientific applications through elastic data organization

Proceedings - IEEE International Conference on Cluster Computing, ICCC

Tian, Yuan; Klasky, Scott; Abbasi, Hasan; Lofstead, Jay; Grout, Ray; Podhorszki, Norbert; Liu, Qing; Wang, Yandong; Yu, Weikuan

Large scale scientific applications are often bottlenecked due to the writing of checkpoint-restart data. Much work has been focused on improving their write performance. With the mounting needs of scientific discovery from these datasets, it is also important to provide good read performance for many common access patterns, which requires effective data organization. To address this issue, we introduce Elastic Data Organization (EDO), which can transparently enable different data organization strategies for scientific applications. Through its flexible data ordering algorithms, EDO harmonizes different access patterns with the underlying file system. Two levels of data ordering are introduced in EDO. One works at the level of data groups (a.k.a process groups). It uses Hilbert Space Filling Curves (SFC) to balance the distribution of data groups across storage targets. Another governs the ordering of data elements within a data group. It divides a data group into sub chunks and strikes a good balance between the size of sub chunks and the number of seek operations. Our experimental results demonstrate that EDO is able to achieve balanced data distribution across all dimensions and improve the read performance of multidimensional datasets in scientific applications. © 2011 IEEE.

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Why oil sticks to limestone

Brady, Patrick V.

A coordination chemistry analysis of oil-calcite adhesion allows waterflood chemistry controls over enhanced oil recovery from limestones to be understood. The model relies on temperature-dependent surface complexation models of calcite and oil. The primary electrostatic bridges holding oil to calcite are calculated to be [-COO-][>CaOH2+], [-COO-][>COOCa+], [>CaSO4-][-COOCa+] and [-COOCa+][>COO-] (“>” denotes calcite surface groups; “-” denotes polar oil surface groups; Mg2+ can substitute for Ca+2). The [-COO-][>CaOH2+] bridge between oil carboxylate and protonated calcite calcium sites is most sensitive to changes in waterflood chemistry. Model calculations predict that increased levels of Ca+2, Mg+2, and SO4-2, alone or in combination, will increase oil recovery from limestones by decreasing the number of [-COO-][>CaOH2+] bridges. Divalent cations decrease the local interfacial potential by decreasing the net negative charge on oil carboxylate groups; SO4-2 coordinates to protonated calcite calcium sites to decrease charge and electrostatic attraction. Increases in ionic strength should increase adhesion by increasing the net charge on each surface, though the effect will be less on calcite. The model presented here requires no fitting parameters yet accurately reproduces observed oil mobilization trends suggesting the model to be a potentially valuable tool for designing chemistries of waterfloods employed in limestones.

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Enabling flexible collective communication offload with triggered operations

Proceedings - Symposium on the High Performance Interconnects, Hot Interconnects

Underwood, Keith D.; Coffman, Jerrie; Larsen, Roy; Hemmert, Karl S.; Barrett, Brian W.; Brightwell, Ronald B.; Levenhagen, Michael

Low latency collective communications are key to application scalability. As systems grow larger, minimizing collective communication time becomes increasingly challenging. Offload is an effective technique for accelerating collective operations; however, algorithms for collective communication constantly evolve such that flexible implementations are critical. This paper presents triggered operations-a semantic building block that allows the key components of collective communications to be offloaded while allowing the host side software to define the algorithm. Simulations are used to demonstrate the performance improvements achievable through the offload of MPI-Allreduce using these building blocks. © 2011 IEEE.

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On source code transformations for steganographic applications

Proceedings - 2011 IEEE/WIC/ACM International Joint Conferences on Web Intelligence and Intelligent Agent Technology - Workshops, WI-IAT 2011

Hulette, Geoffrey C.; Solis, John H.

The amount of publicly available source code on the Internet makes it attractive as a potential message carrier for steganographic applications. Unfortunately, it is often overlooked since embedding information in an undetectable way is challenging. We investigate term rewriting as a method for embedding messages into programs via transformations on source code. We elaborate on several possible transformation strategies and discuss how they might be applied in a steganographic setting. We continue with a discussion on (a) the implications and trade-offs of preserving semantic properties, (b) the relationship between messages and transformations, and (c) how to incorporate existing natural language processing techniques. The goal of this work is to elicit constructive feedback and present ideas that stimulate future work.

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Transient stability and performance based on nonlinear power flow control design of renewable energy systems

Proceedings of the IEEE International Conference on Control Applications

Wilson, David G.; Robinett, Rush D.

In this paper, the swing equations for renewable generators are formulated as a natural Hamiltonian system with externally applied non-conservative forces. A two-step process referred to as Hamiltonian Surface Shaping and Power Flow Control (HSSPFC) is used to analyze and design feedback controllers for the renewable generator system. The results of this research include the determination of the required performance of a proposed Flexible AC Transmission System (FACTS)/storage device, such as a Unified Power Flow Controller (UPFC), to enable the maximum power output of a wind turbine while meeting the power system constraints on frequency and phase. The UPFC is required to operate as both a generator and load (energy storage) on the power system in this design. Necessary and sufficient conditions for stability of renewable generator systems are determined based on the concepts of Hamiltonian systems, power flow, exergy (the maximum work that can be extracted from an energy flow) rate, and entropy rate. An illustrative example demonstrates this HSSPFC methodology. It includes a 600 kW wind turbine, variable speed variable pitch configuration. The wind turbine is operated with a turbulent wind profile for below-rated wind power conditions. The wind turbine is connected in series through a UPFC to the infinite bus. Numerical simulation cases are reviewed that best demonstrate the stability and performance of HSSPFC as applied to a renewable energy system. © 2011 IEEE.

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Adaptive rule-based malware detection employing learning classifier systems: A proof of concept

Proceedings - International Computer Software and Applications Conference

Blount, Jonathan J.; Tauritz, Daniel R.; Mulder, Samuel A.

Efficient and accurate malware detection is increasingly becoming a necessity for society to operate. Existing malware detection systems have excellent performance in identifying known malware for which signatures are available, but poor performance in anomaly detection for zero day exploits for which signatures have not yet been made available or targeted attacks against a specific entity. The primary goal of this paper is to provide evidence for the potential of learning classifier systems to improve the accuracy of malware detection. A proof of concept is presented for adaptive rule-based malware detection employing learning classifier systems, which combines a rule-based expert system with evolutionary algorithm based reinforcement learning, thus creating a self-training adaptive malware detection system which dynamically evolves detection rules. Experimental results are presented which demonstrate the system's ability to learn effective rules from repeated presentations of a tagged training set and show the degree of generalization achieved on an independent test set. © 2011 IEEE.

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Multilayer infrared metamaterial fabrication using membrane projection lithography

Journal of Vacuum Science and Technology. B, Nanotechnology and Microelectronics

Wendt, Joel R.; Brener, Igal; Sinclair, Michael B.

Membrane projection lithography is extended from a single layer fabrication technique to a multilayer process, adding polymeric backfill and planarization after each layer is completed. Unaligned contact lithography is used as a rapid prototyping tool to aid in process development, patterning resist membranes in seconds without requiring long e-beam write times. The fabricated multilayer structures show good resistance to solvent attack from subsequent process steps and demonstrate in-plane and out of plane multilayer metallic inclusions in a dielectric host, which is a critical step in the path to develop bulklike metamaterials at optical frequencies.

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Raman thermometry of microdevices: Comparing methods to minimize error

Spectroscopy (Santa Monica)

Beechem, Thomas E.; Serrano, Justin R.

A study was conducted to demonstrate that the Raman response had the potential to be implemented in several different manners to deduce temperature. Each approach was derived from a different physical mechanism and offered particular advantages and disadvantages. It was demonstrated that temperature was deduced through the analysis of the inelastic energy transfer between the incident laser source and the quantized lattice vibrations in Raman thermometry. The peak position of the Raman signal was derived from the energy of the zone-center optical phonons that were probed during the Raman experiment. The linewidth of a Raman spectrum evolved as a result of the finite lifetime of the zone-center phonons that were being investigated. It was observed that the Raman signal originated as a consequence of the Heisenberg uncertainty principle, which stipulated that the energy of the phonon was measured only to within a certain specificity when the mode being investigated was available for only a finite amount of time.

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Energy and water in the Great Lakes

Tidwell, Vincent C.

The nexus between thermoelectric power production and water use is not uniform across the U.S., but rather differs according to regional physiography, demography, power plant fleet composition, and the transmission network. That is, in some regions water demand for thermoelectric production is relatively small while in other regions it represents the dominate use. The later is the case for the Great Lakes region, which has important implications for the water resources and aquatic ecology of the Great Lakes watershed. This is today, but what about the future? Projected demographic trends, shifting lifestyles, and economic growth coupled with the threat of global climate change and mounting pressure for greater U.S. energy security could have profound effects on the region's energy future. Planning for such an uncertain future is further complicated by the fact that energy and environmental planning and regulatory decisionmaking is largely bifurcated in the region, with environmental and water resource concerns generally taken into account after new energy facilities and technologies have been proposed, or practices are already in place. Based on these confounding needs, the objective of this effort is to develop Great Lakes-specific methods and tools to integrate energy and water resource planning and thereby support the dual goals of smarter energy planning and development, and protection of Great Lakes water resources. Guiding policies for this planning are the Great Lakes and St. Lawrence River Basin Water Resources Compact and the Great Lakes Water Quality Agreement. The desired outcome of integrated energy-water-aquatic resource planning is a more sustainable regional energy mix for the Great Lakes basin ecosystem.

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TYPE SAND Report YEAR 2011
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Energy-water analysis of the 10-year WECC transmission planning study cases

Tidwell, Vincent C.; Passell, Howard

In 2011 the Department of Energy's Office of Electricity embarked on a comprehensive program to assist our Nation's three primary electric interconnections with long term transmission planning. Given the growing concern over water resources in the western U.S. the Western Electricity Coordinating Council (WECC) requested assistance with integrating water resource considerations into their broader electric transmission planning. The result is a project with three overarching objectives: (1) Develop an integrated Energy-Water Decision Support System (DSS) that will enable planners in the Western Interconnection to analyze the potential implications of water stress for transmission and resource planning. (2) Pursue the formulation and development of the Energy-Water DSS through a strongly collaborative process between the Western Electricity Coordinating Council (WECC), Western Governors Association (WGA), the Western States Water Council (WSWC) and their associated stakeholder teams. (3) Exercise the Energy-Water DSS to investigate water stress implications of the transmission planning scenarios put forward by WECC, WGA, and WSWC. The foundation for the Energy-Water DSS is Sandia National Laboratories Energy-Power-Water Simulation (EPWSim) model (Tidwell et al. 2009). The modeling framework targets the shared needs of energy and water producers, resource managers, regulators, and decision makers at the federal, state and local levels. This framework provides an interactive environment to explore trade-offs, and 'best' alternatives among a broad list of energy/water options and objectives. The decision support framework is formulated in a modular architecture, facilitating tailored analyses over different geographical regions and scales (e.g., state, county, watershed, interconnection). An interactive interface allows direct control of the model and access to real-time results displayed as charts, graphs and maps. The framework currently supports modules for calculating water withdrawal and consumption for current and planned electric power generation; projected water demand from competing use sectors; and, surface and groundwater availability. WECC's long range planning is organized according to two target planning horizons, a 10-year and a 20-year. This study supports WECC in the 10-year planning endeavor. In this case the water implications associated with four of WECC's alternative future study cases (described below) are calculated and reported. In future phases of planning we will work with WECC to craft study cases that aim to reduce the thermoelectric footprint of the interconnection and/or limit production in the most water stressed regions of the West.

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Elements of a pragmatic approach for dealing with bias and uncertainty in experiments through predictions : experiment design and data conditioning; %22real space%22 model validation and conditioning; hierarchical modeling and extrapolative prediction

Romero, Vicente J.

This report explores some important considerations in devising a practical and consistent framework and methodology for utilizing experiments and experimental data to support modeling and prediction. A pragmatic and versatile 'Real Space' approach is outlined for confronting experimental and modeling bias and uncertainty to mitigate risk in modeling and prediction. The elements of experiment design and data analysis, data conditioning, model conditioning, model validation, hierarchical modeling, and extrapolative prediction under uncertainty are examined. An appreciation can be gained for the constraints and difficulties at play in devising a viable end-to-end methodology. Rationale is given for the various choices underlying the Real Space end-to-end approach. The approach adopts and refines some elements and constructs from the literature and adds pivotal new elements and constructs. Crucially, the approach reflects a pragmatism and versatility derived from working many industrial-scale problems involving complex physics and constitutive models, steady-state and time-varying nonlinear behavior and boundary conditions, and various types of uncertainty in experiments and models. The framework benefits from a broad exposure to integrated experimental and modeling activities in the areas of heat transfer, solid and structural mechanics, irradiated electronics, and combustion in fluids and solids.

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Linear diffusion into a Faraday cage

Chen, Kenneth C.; Lin, Yau T.; Warne, Larry K.; Merewether, Kimball O.

Linear lightning diffusion into a Faraday cage is studied. An early-time integral valid for large ratios of enclosure size to enclosure thickness and small relative permeability ({mu}/{mu}{sub 0} {le} 10) is used for this study. Existing solutions for nearby lightning impulse responses of electrically thick-wall enclosures are refined and extended to calculate the nearby lightning magnetic field (H) and time-derivative magnetic field (HDOT) inside enclosures of varying thickness caused by a decaying exponential excitation. For a direct strike scenario, the early-time integral for a worst-case line source outside the enclosure caused by an impulse is simplified and numerically integrated to give the interior H and HDOT at the location closest to the source as well as a function of distance from the source. H and HDOT enclosure response functions for decaying exponentials are considered for an enclosure wall of any thickness. Simple formulas are derived to provide a description of enclosure interior H and HDOT as well. Direct strike voltage and current bounds for a single-turn optimally-coupled loop for all three waveforms are also given.

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Sandia National Laboratories performance assessment methodology for long-term environmental programs : the history of nuclear waste management

Bonano, Evaristo J.

Sandia National Laboratories (SNL) is the world leader in the development of the detailed science underpinning the application of a probabilistic risk assessment methodology, referred to in this report as performance assessment (PA), for (1) understanding and forecasting the long-term behavior of a radioactive waste disposal system, (2) estimating the ability of the disposal system and its various components to isolate the waste, (3) developing regulations, (4) implementing programs to estimate the safety that the system can afford to individuals and to the environment, and (5) demonstrating compliance with the attendant regulatory requirements. This report documents the evolution of the SNL PA methodology from inception in the mid-1970s, summarizing major SNL PA applications including: the Subseabed Disposal Project PAs for high-level radioactive waste; the Waste Isolation Pilot Plant PAs for disposal of defense transuranic waste; the Yucca Mountain Project total system PAs for deep geologic disposal of spent nuclear fuel and high-level radioactive waste; PAs for the Greater Confinement Borehole Disposal boreholes at the Nevada National Security Site; and PA evaluations for disposal of high-level wastes and Department of Energy spent nuclear fuels stored at Idaho National Laboratory. In addition, the report summarizes smaller PA programs for long-term cover systems implemented for the Monticello, Utah, mill-tailings repository; a PA for the SNL Mixed Waste Landfill in support of environmental restoration; PA support for radioactive waste management efforts in Egypt, Iraq, and Taiwan; and, most recently, PAs for analysis of alternative high-level radioactive waste disposal strategies including repositories deep borehole disposal and geologic repositories in shale and granite. Finally, this report summarizes the extension of the PA methodology for radioactive waste disposal toward development of an enhanced PA system for carbon sequestration and storage systems. These efforts have produced a generic PA methodology for the evaluation of waste management systems that has gained wide acceptance within the international community. This report documents how this methodology has been used as an effective management tool to evaluate different disposal designs and sites; inform development of regulatory requirements; identify, prioritize, and guide research aimed at reducing uncertainties for objective estimations of risk; and support safety assessments.

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Salinas : theory manual

Reese, Garth M.; Walsh, Timothy W.; Bhardwaj, Manoj K.

Salinas provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of structural systems. This manual describes the theory behind many of the constructs in Salinas. For a more detailed description of how to use Salinas, we refer the reader to Salinas, User's Notes. Many of the constructs in Salinas are pulled directly from published material. Where possible, these materials are referenced herein. However, certain functions in Salinas are specific to our implementation. We try to be far more complete in those areas. The theory manual was developed from several sources including general notes, a programmer notes manual, the user's notes and of course the material in the open literature.

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Results 66001–66200 of 99,299
Results 66001–66200 of 99,299