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Figures of merit for production HPC

Allan, Benjamin A.

This report summarizes a set of figures of merit of interest in monitoring the hardware and hardware usage in a Sandia high performance computing (HPC) center. These figures are computable from high frequency monitoring data and other non-metric data and may aid administrators and customer support personnel in their decision processes. The figures are derived from interviews of the HPC center staff. The figures are in many cases simplistic data reductions, but they are our initial targets in creating dashboards that turn voluminous monitoring data into actionable information. Because simplistic reductions may obscure as well as reveal the situation under study, we also document the necessary 'drill-down' and %60exploration' views needed to make the data better understood quickly. These figures of merit may be compared to dashboarding tools documented by other HPC centers.

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TYPE SAND Report YEAR 2019
DOIOSTI

Development of eXternal Nuclear Reaction Analysis (XNRA) Detection Technique for Quantifying Light Isotope Concentrations

Doyle, B.L.

The National Nuclear Security Administration’s Tritium Sustainment Program is responsible for the design, development, demonstration, testing, analysis, and characterization of tritium-producing burnable absorber rods (TPBARs) and their components used to produce tritium for the nation’s strategic stockpile. The FY19 call for proposals included the specific basic science research topic, “Demonstration and evaluation of advanced characterization methods, particularly for quantifying the concentration of light isotopes (1H, 3H, 3He, and 4He, 6Li and 7Li) in metal or ceramic matrices”. Last year the same language appeared in the call for proposals, and a project IWO-389859 was awarded to the Ion Beam Lab (IBL) at Sandia-NM which was successful using Elastic Recoil Detection, but in the future could have resulted in tritium contamination that jeopardized other equally important NNSA projects. An alternative approach using deuterium nuclear reaction analysis was proposed and funded in FY2019 which was also successful and eliminated any possibility of contaminating the Ion Beam Laboratory with tritium, and will be described in this report.

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TYPE SAND Report YEAR 2019
DOIOSTI

Cas9 Protein Post-translational Modifications (PTMs): A Potential Biomarker of Gene-editing

Podlevsky, Joshua

The clustered regularly interspaced short palindromic repeats (CRISPR) arrays and the CRISPR associated (Cas) proteins comprise a prevalent prokaryotic and archaeal adaptive immune system. The CRISPR/Cas9 system has been coopted for and become the ubiquitous gene-editing system due to the simplicity of requiring minimally the CRISPR RNA components and Cas9 protein for specific DNA sequence alteration. CRISPR/Cas9 has been extensively used for gene-editing a wide range of species with human patient trails currently underway. However, unsanctioned genome editing is a national security and public health threat that can cause serious permanent illness and death as well as having the potential for very long-lasting effects over generations due to genetic inheritance of the gene-edit. While the Cas9 protein would appear as a highly specific indicator of exposure to gene-editing reagents, the bacterial origins of CRISPR/Cas9 creates a daunting problem for detection. Bacterial Cas9 would then generate false-positives for detecting gene-editing by conventional molecular biology techniques. Antibody-based assays for Cas9 would be unable to distinguish between Cas9 expressed in human cells for gene-editing and highly common unrelated Cas9 from bacterial infections. Posttranslational modifications of proteins are highly cell specific and hold the potential for discerning the cellular origins of a Cas9 protein and the differentiating between bacterial and gene-editing CRISPR/Cas9. The work described herein is in progress towards the identification of Cas9 post-translational modifications from bacterial and human cell expressed Cas9.

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TYPE Other Report YEAR 2019
DOIOSTI

Xyce Parallel Electronic Simulator Users' Guide (V.6.12)

Keiter, Eric R.; Aadithya, Karthik V.; Mei, Ting; Russo, Thomas V.; Schiek, Richard L.; Sholander, Peter E.; Thornquist, Heidi K.; Verley, Jason C.

This manual describes the use of the Xyce Parallel Electronic Simulator. Xyce has been designed as a SPICE-compatible, high-performance analog circuit simulator, and has been written to support the simulation needs of the Sandia National Laboratories electrical designers. This development has focused on improving capability over the current state-of-the-art in the following areas: Capability to solve extremely large circuit problems by supporting large-scale parallel computing platforms (up to thousands of processors). This includes support for most popular parallel and serial computers. A differential-algebraic-equation (DAE) formulation, which better isolates the device model package from solver algorithms. This allows one to develop new types of analysis without requiring the implementation of analysis-specific device models. Device models that are specifically tailored to meet Sandia's needs, including some radiation-aware devices (for Sandia users only). Object-oriented code design and implementation using modern coding practices. Xyce is a parallel code in the most general sense of the phrase -- a message passing parallel implementation -- which allows it to run efficiently a wide range of computing platforms. These include serial, shared-memory and distributed-memory parallel platforms. Attention has been paid to the specific nature of circuit-simulation problems to ensure that optimal parallel efficiency is achieved as the number of processors grows.

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TYPE SAND Report YEAR 2019
DOIOSTI

Xyce Parallel Electronic Simulator Reference Guide (V.6.12)

Keiter, Eric R.; Aadithya, Karthik V.; Mei, Ting; Russo, Thomas V.; Schiek, Richard L.; Sholander, Peter E.; Thornquist, Heidi K.; Verley, Jason C.

This document is a reference guide to the Xyce Parallel Electronic Simulator, and is a companion document to the Xyce Users' Guide [1]. The focus of this document is (to the extent possible) exhaustively list device parameters, solver options, parser options, and other usage details of Xyce. This document is not intended to be a tutorial. Users who are new to circuit simulation are better served by the Xyce Users' Guide.

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TYPE SAND Report YEAR 2019
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Finite-element modeling for an explosively loaded ferroelectric generator

Niederhaus, John H.J.; Yang, Pin; Diantonio, Christopher; Vunni, George

A preliminary finite-element model has been developed using the ALEGRA-FE code for explosive driven depoling of a PZT 95/5 ferroelectric generator. The ferroelectric material is characterized using hysteresis-loop and hydrostatic depoling tests. These characteristics are incorporated into ALEGRA-FE simulations that model the explosive drive mechanism and shock environment in the material leading to depoling, as well as the ferroelectric response and the behavior of a coupled circuit. The ferroelectric-to-antiferroelectric phase transition is captured, producing an output voltage pulse that matches experimental data to within 10% in rise time, and to within about 15% for the final voltage. Both experimental and modeled pulse magnitudes are less than the theoretical maximum output of the material. Observations from materials characterization suggest that unmodeled effects such as trapped charge in the stored FEG material may have influenced the experimentally observed output.

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TYPE SAND Report YEAR 2019
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Microwave Doppler Charge Velocimetry for Narrow and Wide Bandgap Semiconductors

Shaner, Eric A.; Klem, John F.; Stephenson, Chad A.; Kadlec, Clark N.; Goldflam, Michael; Wasserman, Daniel

Characterization of vertical transport in semiconductor heterostructures is extremely difficult and often impractical. Measurements that are relatively straight forward in lateral transport using Hall methods, such as quantifying carrier density or mobility, have no analog in conventional vertical devices. Doppler charge velocimetry may provide an alternative approach to obtaining transport information. We hypothesize that we can drive vertical currents in structures like heterojunction bipolar transistors or nBn detectors, illuminate them with microwaves, and directly measure the carrier velocities through Doppler shifts imparted on the reflected microwave signal. Some challenges involve providing optical injection and working in the vertical geometry required to extract the desired information. While progress was made to this end, experiments have not yet proved successful. Implications for infrared material characterization are summarized at the end of this document.

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TYPE SAND Report YEAR 2019
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ParaChoice Model

Proctor, Camron; Wiryadinata, Steven; Fruetel, Julia A.

Sandia National Laboratories' (SNL's) Parametric Choice Model (ParaChoice) supports the U.S. Department of Energy Vehicle Technologies Office (VTO) mission. Using early-stage research as input, ParaChoice supports the informed development of technology that will improve affordability of transportation, while encouraging innovation and reducing dependence on petroleum. Analysis with ParaChoice enables exploration of key factors that influence consumer choice, as well as projecting the effects of technology, fuel, and infrastructure development for the vehicle fleet mix. Because of the distinct differences between requirements, needs, and use patterns for light duty vehicles (LDVs) relative to heavy duty vehicles (HDVs), this project separately models the dynamics of each of these segments to accurately characterize the factors that influence technology adoption.

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TYPE Other Report YEAR 2019
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Results 20401–20500 of 99,299
Results 20401–20500 of 99,299