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Defect reaction network in Si-doped InP : numerical predictions

Schultz, Peter A.

This Report characterizes the defects in the defect reaction network in silicon-doped, n-type InP deduced from first principles density functional theory. The reaction network is deduced by following exothermic defect reactions starting with the initially mobile interstitial defects reacting with common displacement damage defects in Si-doped InP until culminating in immobile reaction products. The defect reactions and reaction energies are tabulated, along with the properties of all the silicon-related defects in the reaction network. This Report serves to extend the results for intrinsic defects in SAND 2012-3313: %E2%80%9CSimple intrinsic defects in InP: Numerical predictions%E2%80%9D to include Si-containing simple defects likely to be present in a radiation-induced defect reaction sequence.

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TYPE SAND Report YEAR 2013
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Effect of DC voltage pulses on memristor behavior

Evans, Brian R.

Current knowledge of memristor behavior is limited to a few physical models of which little comprehensive data collection has taken place. The purpose of this research is to collect data in search of exploitable memristor behavior by designing and implementing tests on a HP Labs Rev2 Memristor Test Board. The results are then graphed in their optimal format for conceptualizing behavioral patterns. This series of experiments has concluded the existence of an additional memristor state affecting the behavior of memristors when pulsed with positively polarized DC voltages. This effect has been observed across multiple memristors and data sets. The following pages outline the process that led to the hypothetical existence and eventual proof of this additional state of memristor behavior.

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TYPE SAND Report YEAR 2013
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Analysis of Alternatives for Risk Assessment Methodologies and Tools

Nachtigal, Noel M.; Fruetel, Julia A.; Gleason, Nathaniel J.; Helms, Jovana; Imbro, Dennis R.; Sumner, Matthew

The purpose of this document is to provide a basic overview and understanding of risk assessment methodologies and tools from the literature and to assess the suitability of these methodologies and tools for cyber risk assessment. Sandia National Laboratories (SNL) performed this review in support of risk modeling activities performed for the Stakeholder Engagement and Cyber Infrastructure Resilience (SECIR) division of the Department of Homeland Security (DHS) Office of Cybersecurity and Communications (CS&C). The set of methodologies and tools covered in this document is not intended to be exhaustive; instead, it focuses on those that are commonly used in the risk assessment community. The classification of methodologies and tools was performed by a group of analysts with experience in risk analysis and cybersecurity, and the resulting analysis of alternatives has been tailored to address the needs of a cyber risk assessment.

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TYPE SAND Report YEAR 2013
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Towards understanding of Nipah virus attachment protein assembly and the role of protein affinity and crowding for membrane curvature events

Hayden, Carl C.; Negrete, Oscar N.; Davis, Ryan W.

Pathogenic viruses are a primary threat to our national security and to the health and economy of our world. Effective defense strategies to combat viral infection and spread require the development of understanding of the mechanisms that these pathogens use to invade the host cell. We present in this report results of our research into viral particle recognition and fusion to cell membranes and the role that protein affinity and confinement in lipid domains plays in membrane curvature in cellular fusion and fission events. Herein, we describe 1) the assembly of the G attachment protein of Nipah virus using point mutation studies to define its role in viral particle fusion to the cell membrane, 2) how lateral pressure of membrane bound proteins induce curvature in model membrane systems, and 3) the role of membrane curvature in the selective partitioning of molecular receptors and specific affinity of associated proteins.

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TYPE SAND Report YEAR 2013
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Test report : Raytheon / KTech RK30 Energy Storage System

Rosewater, David

The Department of Energy Office of Electricity (DOE/OE), Sandia National Laboratories (SNL) and the Base Camp Integration Lab (BCIL) partnered together to incorporate an energy storage system into a microgrid configured Forward Operating Base to reduce the fossil fuel consumption and to ultimately save lives. Energy storage vendors will be sending their systems to SNL Energy Storage Test Pad (ESTP) for functional testing and then to the BCIL for performance evaluation. The technologies that will be tested are electro-chemical energy storage systems comprising of lead acid, lithium-ion or zinc-bromide. Raytheon/KTech has developed an energy storage system that utilizes zinc-bromide flow batteries to save fuel on a military microgrid. This report contains the testing results and some limited analysis of performance of the Raytheon/KTech Zinc-Bromide Energy Storage System.

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TYPE SAND Report YEAR 2013
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Potential use of battery packs from NCAP tested vehicles

Lamb, Joshua; Orendorff, Christopher

Several large electric vehicle batteries available to the National Highway Traffic Safety Administration are candidates for use in future safety testing programs. The batteries, from vehicles subjected to NCAP crashworthiness testing, are considered potentially damaged due to the nature of testing their associated vehicles have been subjected to. Criteria for safe shipping to Sandia is discussed, as well as condition the batteries must be in to perform testing work. Also discussed are potential tests that could be performed under a variety of conditions. The ultimate value of potential testing performed on these cells will rest on the level of access available to the battery pack, i.e. external access only, access to the on board monitoring system/CAN port or internal electrical access to the battery. Greater access to the battery than external visual and temperature monitoring would likely require input from the battery manufacturer.

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Simulation information regarding Sandia National Laboratories trinity capability improvement metric

Agelastos, Anthony M.; Lin, Paul T.

Sandia National Laboratories, Los Alamos National Laboratory, and Lawrence Livermore National Laboratory each selected a representative simulation code to be used as a performance benchmark for the Trinity Capability Improvement Metric. Sandia selected SIERRA Low Mach Module: Nalu, which is a uid dynamics code that solves many variable-density, acoustically incompressible problems of interest spanning from laminar to turbulent ow regimes, since it is fairly representative of implicit codes that have been developed under ASC. The simulations for this metric were performed on the Cielo Cray XE6 platform during dedicated application time and the chosen case utilized 131,072 Cielo cores to perform a canonical turbulent open jet simulation within an approximately 9-billion-elementunstructured- hexahedral computational mesh. This report will document some of the results from these simulations as well as provide instructions to perform these simulations for comparison.

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HPCG Benchmark Technical Specification

Heroux, Michael A.

The High Performance Conjugate Gradient (HPCG) benchmark [cite SNL, UTK reports] is a tool for ranking computer systems based on a simple additive Schwarz, symmetric Gauss-Seidel preconditioned conjugate gradient solver. HPCG is similar to the High Performance Linpack (HPL), or Top 500, benchmark [1] in its purpose, but HPCG is intended to better represent how today’s applications perform. In this paper we describe the technical details of HPCG: how it is designed and implemented, what code transformations are permitted and how to interpret and report results.

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Contingency contractor optimization

Gearhart, Jared L.; Adair, Kristin L.; Jones, Katherine; Bandlow, Alisa; Detry, Richard J.; Durfee, Justin D.; Jones, Dean A.; Martin, Nathaniel; Nanco, Alan

The goal of Phase 3 the OSD ATL Contingency Contractor Optimization (CCO) project is to create an engineering prototype of a tool for the contingency contractor element of total force planning during the Support for Strategic Analysis (SSA). An optimization model was developed to determine the optimal mix of military, Department of Defense (DoD) civilians, and contractors that accomplishes a set of user defined mission requirements at the lowest possible cost while honoring resource limitations and manpower use rules. An additional feature allows the model to understand the variability of the Total Force Mix when there is uncertainty in mission requirements.

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Development of ab initio techniques critical for future science-based explosives R&D

Wixom, Ryan R.; Wills, Ann E.

Density Functional Theory (DFT) has emerged as an indispensable tool in materials research, since it can accurately predict properties of a wide variety of materials at both equilibrium and extreme conditions. However, for organic molecular crystal explosives, successful application of DFT has largely failed due to the inability of current exchange-correlation functionals to correctly describe intermolecular van der Waals (vdWs) forces. Despite this, we have discovered that even with no treatment of vdWs bonding, the AM05 functional and DFT based molecular dynamics (MD) could be used to study the properties of molecular crystals under compression. We have used DFT-MD to predict the unreacted Hugoniots for PETN and HNS and validated the results by comparison with crystalline and porous experimental data. Since we are also interested in applying DFT methods to study the equilibrium volume properties of explosives, we studied the nature of the vdWs bonding in pursuit of creating a new DFT functional capable of accurately describing equilibrium bonding of molecular crystals. In this report we discuss our results for computing shock Hugoniots of molecular crystals and also what was learned about the nature of bonding in these materials.

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Brine-in-crude-oil emulsions at the Strategic Petroleum Reserve

Nemer, Martin; Lord, David; Macdonald, Terry L.

Metastable water-in-crude-oil emulsion formation could occur in a Strategic Petroleum Reserve (SPR) cavern if water were to flow into the crude-oil layer at a sufficient rate. Such a situation could arise during a drawdown from a cavern with a broken-hanging brine string. A high asphaltene content (> 1.5 wt %) of the crude oil provides the strongest predictor of whether a metastable water-in-crude-oil emulsion will form. However there are many crude oils with an asphaltene content > 1.5 wt % that don't form stable emulsions, but few with a low asphaltene content that do form stable emulsions. Most of the oils that form stable emulsions are "sour" by SPR standards indicating they contain total sulfur > 0.50 wt %.

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Comparison of open-source linear programming solvers

Gearhart, Jared L.; Adair, Kristin L.; Detry, Richard J.; Durfee, Justin D.; Jones, Katherine; Martin, Nathaniel

When developing linear programming models, issues such as budget limitations, customer requirements, or licensing may preclude the use of commercial linear programming solvers. In such cases, one option is to use an open-source linear programming solver. A survey of linear programming tools was conducted to identify potential open-source solvers. From this survey, four open-source solvers were tested using a collection of linear programming test problems and the results were compared to IBM ILOG CPLEX Optimizer (CPLEX) [1], an industry standard. The solvers considered were: COIN-OR Linear Programming (CLP) [2], [3], GNU Linear Programming Kit (GLPK) [4], lp_solve [5] and Modular In-core Nonlinear Optimization System (MINOS) [6]. As no open-source solver outperforms CPLEX, this study demonstrates the power of commercial linear programming software. CLP was found to be the top performing open-source solver considered in terms of capability and speed. GLPK also performed well but cannot match the speed of CLP or CPLEX. lp_solve and MINOS were considerably slower and encountered issues when solving several test problems.

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Test Report : GS Battery, EPC power HES RESCU

Rosewater, David; Schenkman, Benjamin L.; Borneo, Daniel R.

The Department of Energy Office of Electricity (DOE/OE), Sandia National Laboratories (SNL) and the Base Camp Integration Lab (BCIL) partnered together to incorporate an energy storage system into a microgrid configured Forward Operating Base to reduce the fossil fuel consumption and to ultimately save lives. Energy storage vendors will be sending their systems to SNL Energy Storage Test Pad (ESTP) for functional testing and then to the BCIL for performance evaluation. The technologies that will be tested are electro-chemical energy storage systems comprising of lead acid, lithium-ion or zinc-bromide. GS Battery and EPC Power have developed an energy storage system that utilizes zinc-bromide flow batteries to save fuel on a military microgrid. This report contains the testing results and some limited analysis of performance of the GS Battery, EPC Power HES RESCU.

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Generic solar photovoltaic system dynamic simulation model specification

Ellis, Abraham; Elliott, Ryan T.

This document is intended to serve as a specification for generic solar photovoltaic (PV) system positive-sequence dynamic models to be implemented by software developers and approved by the WECC MVWG for use in bulk system dynamic simulations in accordance with NERC MOD standards. Two specific dynamic models are included in the scope of this document. The first, a Central Station PV System model, is intended to capture the most important dynamic characteristics of large scale (> 10 MW) PV systems with a central Point of Interconnection (POI) at the transmission level. The second, a Distributed PV System model, is intended to represent an aggregation of smaller, distribution-connected systems that comprise a portion of a composite load that might be modeled at a transmission load bus.

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Polymers for hydrogen infrastructure and vehicle fuel systems :

Barth, Rachel R.; San Marchi, Chris

This document addresses polymer materials for use in hydrogen service. Section 1 summarizes the applications of polymers in hydrogen infrastructure and vehicle fuel systems and identifies polymers used in these applications. Section 2 reviews the properties of polymer materials exposed to hydrogen and/or high-pressure environments, using information obtained from published, peer-reviewed literature. The effect of high pressure on physical and mechanical properties of polymers is emphasized in this section along with a summary of hydrogen transport through polymers. Section 3 identifies areas in which fuller characterization is needed in order to assess material suitability for hydrogen service.

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Pathogenicity island mobility and gene content

Williams, Kelly P.

Key goals towards national biosecurity include methods for analyzing pathogens, predicting their emergence, and developing countermeasures. These goals are served by studying bacterial genes that promote pathogenicity and the pathogenicity islands that mobilize them. Cyberinfrastructure promoting an island database advances this field and enables deeper bioinformatic analysis that may identify novel pathogenicity genes. New automated methods and rich visualizations were developed for identifying pathogenicity islands, based on the principle that islands occur sporadically among closely related strains. The chromosomally-ordered pan-genome organizes all genes from a clade of strains; gaps in this visualization indicate islands, and decorations of the gene matrix facilitate exploration of island gene functions. A %E2%80%9Clearned phyloblocks%E2%80%9D method was developed for automated island identification, that trains on the phylogenetic patterns of islands identified by other methods. Learned phyloblocks better defined termini of previously identified islands in multidrug-resistant Klebsiella pneumoniae ATCC BAA-2146, and found its only antibiotic resistance island.

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Sculpt test problem analysis

Sweetser, John D.

This report details Sculpt's implementation from a user's perspective. Sculpt is an automatic hexahedral mesh generation tool developed at Sandia National Labs by Steve Owen. 54 predetermined test cases are studied while varying the input parameters (Laplace iterations, optimization iterations, optimization threshold, number of processors) and measuring the quality of the resultant mesh. This information is used to determine the optimal input parameters to use for an unknown input geometry. The overall characteristics are covered in Chapter 1. The speci c details of every case are then given in Appendix A. Finally, example Sculpt inputs are given in B.1 and B.2.

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Karst characterization in a semi-arid region using gravity, seismic, and resistivity geophysical techniques

Barnhart, Kevin S.

We proposed to customize emerging in situ geophysical monitoring technology to generate time-series data during sporadic rain events in a semi-arid region. Electrodes were to be connected to wireless \nodes" which can be left in the eld for many months. Embedded software would then increase sampling frequency during periods of rainfall. We hypothesized that this contrast between no-volume ow in karst passageways dur- ing dry periods and partial- or saturated-volume ow during a rain event is detectable by these Wireless Sensor Network (WSN) geophysical nodes, we call this a Wireless Resistivity Network (WRN). The development of new methodologies to characterize semi-arid karst hydrology is intended to augment Sandia National Laboratorys mission to lead e orts in energy technologies, waste disposal and climate security by helping to identify safe and secure regions and those that are at risk. Development and initial eld testing identi ed technological barriers to using WRNs for identifying semi-arid karst, exposing R&D which can be targeted in the future. Gravity, seismic, and resis- tivity surveys elucidated how each technique might e ectively be used to characterize semi-arid karst. This research brings to light the importance and challenges with char- acterizing semi-arid karst through a multi-method geophysical study. As there have been very few studies with this emphasis, this study has expanded the body of practical experience needed to protect the nations water and energy security interests.

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Effect of pressure vents on the fast cookoff of energetic materials

Cooper, Marcia; Oliver, Michael S.; Erikson, William W.

The effect of vents on the fast cookoff of energetic materials is studied through experimental modifications to the confinement vessel of the Radiant Heat Fast Cookoff Apparatus. Two venting schemes were investigated: 1) machined grooves at the EM-cover plate interface; 2) radial distribution of holes in PEEK confiner. EM materials of PBXN-109 and PBX 9502 were tested. Challenges with the experimental apparatus and EM materials were identified such that studying the effect of vents as an independent parameter was not realized. The experimental methods, data and post-test observations are presented and discussed.

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Results 55601–55800 of 99,299
Results 55601–55800 of 99,299