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Radiation Effects Science: Advancing the Frontiers of Science and Engineering

Barbour, J.C.

Recent improvements in the radiation effects science capability at Sandia have achieved the following: Record gamma-ray outputs at HERMES enable qualification for Life Extension Programs (LEPs) and evaluation of electromagnetic pulse (EMP) effects on electric grid elements; Completed blind comparison for model validation of cavity system generated EMP in advanced computer simulations; For the first time, new diagnostics provide a high resolution photon energy spectrum on Z (Grand Challenge LDRD); ACRR completed record number of operations, two years in a row, to support design and qualification; Installed the nation’s largest GHz electromagnetic test chamber for design and qualification.

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TYPE SAND Report YEAR 2016
DOIOSTI

NMSBA - Twist Resist - Rotational Exercise Module

Reece, Blake D.; Berger, Jason E.; Guido, Steven F.; Linker, Taylor

This report contains a summary of the work completed to develop a modular, rotational exercise device. In the report are images, diagrams, and explanations of the efforts contributed to the project since its inception. The purpose of this document is to provide a walk-through of the progress on this project, from the initial design concepts to the final design and work done, so that the customer (Twist Resist), or individuals/firms who work on this project in the future will have a springboard of ideas/concepts to work from.

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TYPE Other Report YEAR 2016
DOIOSTI

Convergence Study in Global Sensitivity Analysis

Harmon, Rebecca; Khalil, Mohammad; Najm, Habib N.; Safta, Cosmin

Monte Carlo (MC) sampling is a common method used to randomly sample a range of scenarios. The associated error follows a predictable rate of convergence of $1/\sqrt{N}$, such that quadrupling the sample size halves the error. This method is often employed in performing global sensitivity analysis which computes sensitivity indices, measuring fractional contributions of uncertain model inputs to the total output variance. In this study, several models are used to observe the rate of decay in the MC error in the estimation of the conditional variance, the total variance in the output, and the global sensitivity indices. The purpose is to examine the rate of convergence of the error in existing specialized, albeit MC-based, sampling methods for estimation of the sensitivity indices. It was found that the conditional variances and sensitivity indices all follow the $1/\sqrt{N}$ convergence rate. Future work will test the convergence of observables from more complex models such as ignition time in combustion.

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TYPE Other Report YEAR 2016
DOIOSTI

Simulation of Distributed PV Power Output in Oahu Hawaii

Lave, Matt

Distributed solar photovoltaic (PV) power generation in Oahu has grown rapidly since 2008. For applications such as determining the value of energy storage, it is important to have PV power output timeseries. Since these timeseries of not typically measured, here we produce simulated distributed PV power output for Oahu. Simulated power output is based on (a) satellite-derived solar irradiance, (b) PV permit data by neighborhood, and (c) population data by census block. Permit and population data was used to model locations of distributed PV, and irradiance data was then used to simulate power output. PV power output simulations are presented by sub-neighborhood polygons, neighborhoods, and for the whole island of Oahu. Summary plots of annual PV energy and a sample week timeseries of power output are shown, and a the files containing the entire timeseries are described.

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TYPE SAND Report YEAR 2016
DOIOSTI

TDAAPS 2: Acoustic Wave Propagation in Attenuative Moving Media

Preston, Leiph

This report outlines recent enhancements to the TDAAPS algorithm first described by Symons et al., 2005. One of the primary additions to the code is the ability to specify an attenuative media using standard linear fluid mechanisms to match reasonably general frequency versus loss curves, including common frequency versus loss curves for the atmosphere and seawater. Other improvements that will be described are the addition of improved numerical boundary conditions via various forms of Perfectly Matched Layers, enhanced accuracy near high contrast media interfaces, and improved physics options.

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TYPE SAND Report YEAR 2016
DOIOSTI

Implementation of Fast Emulator-based Code Calibration

Bowman, Nathaniel; Denman, Matthew R.

Calibration is the process of using experimental data to gain more precise knowledge of simulator inputs. This process commonly involves the use of Markov-chain Monte Carlo, which requires running a simulator thousands of times. If we can create a faster program, called an emulator, that mimics the outputs of the simulator for an input range of interest, then we can speed up the process enough to make it feasible for expensive simulators. To this end, we implement a Gaussian-process emulator capable of reproducing the behavior of various long-running simulators to within acceptable tolerance. This fast emulator can be used in place of a simulator to run Markov-chain Monte Carlo in order to calibrate simulation parameters to experimental data. As a demonstration, this emulator is used to calibrate the inputs of an actual simulator against two sodium-fire experiments.

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TYPE SAND Report YEAR 2016
DOIOSTI

Modeling Primary Atomization of Liquid Fuels using a Multiphase DNS/LES Approach

Arienti, Marco

As part of a Laboratory Directed Research and Development project, we are developing a modeling-and-simulation capability to study fuel direct injection in automotive engines. Predicting mixing and combustion at realistic conditions remains a challenging objective of energy science. And it is a research priority in Sandia’s mission-critical area of energy security, being also relevant to many flows in defense and climate. High-performance computing applied to this non-linear multi-scale problem is key to engine calculations with increased scientific reliability.

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TYPE Other Report YEAR 2016
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Lens and Camera Arrays for Sky Surveys and Space Surveillance

Ackermann, Mark R.; Cox, David; Mcgraw, John; Zimmer, Peter

In recent years, a number of sky survey projects have chosen to use arrays of commercia l cameras coupled with commercial photographic lenses to enable low-cost, wide-area observation. Projects such as SuperWASP, FAVOR, Raptor, Lotis, PANOPTES, and Dragonfly rely on multiple cameras with commercial lenses to image wide areas of the sky each night. The sensors are usually commercial astronomical change coupled devices (CCD) or digital single reflex (DSLR) cameras, while the lenses are large-aperture, high-end consumer items intended for general photography. While much of this equipment is very capable and relatively inexpensive, this approach comes with a number of significant limitations that reduce sensitivity and overall utility of the image data. The most frequently encountered limitations include lens vignetting, narrow spectral bandpass, and relatively large point spread function. Understanding these limits helps to assess the utility of the data, and identify areas where advanced optical designs could significantly improve survey performance.

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TYPE SAND Report YEAR 2016
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Energy Storage Financing: A Roadmap for Accelerating Market Growth

Baxter, Richard

Project financing is emerging as the linchpin for the future health, direction, and momentum of the energy storage industry. Market leaders have so far relied on self-funding or captive lending arrangements to fund projects. New lenders are proceeding hesitantly as they lack a full understanding of the technology, business, and credit risks involved in this rapidly changing market. The U.S. Department of Energy is poised to play a critical role in expanding access to capital by reducing the barriers to entry for new lenders, and providing trusted analytical benchmarks to better judge and price the risk in systematic ways.

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TYPE SAND Report YEAR 2016
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Results 42201–42400 of 100,993
Results 42201–42400 of 100,993
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