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Test definitions for the evaluation of digital waveform recorders

Hart, Darren H.; Harris, James M.

This Test Definition for the Evaluation of Digitizing Waveform Recorders (DWR) defines the process that can be performed as part of the evaluation and testing of geophysical sensors, digitizers, sensor subsystems and geophysical station/array systems. The objectives are to (1) evaluate the overall technical performance of the DWR, measure the distortions introduced by the high resolution digitizers and provide a performance check of the internal calibrator if provided and (2) evaluate the technical performance of the DWR for a specific sensor application. The results of these evaluations can be compared to the manufacturer's specifications and any relevant application requirements or specifications.

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Test definitions for the evaluation of infrasound sensors

Hart, Darren H.; Harris, James M.

Most test methodologies referenced in this Test Definition and Test Procedures were designed by Sandia specifically for geophysical instrumentation evaluation. When appropriate, test instrumentation calibration is traceable to the National Institute for Standards Technology (NIST). The objectives are to evaluate the overall technical performance of the infrasound sensor. The results of these evaluations can be compared to the manufacturer's specifications and any relevant application requirements or specifications.

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Electrically tunable extraordinary optical transmission gratings

Proposed for publication in Nature Photonics.

Shaner, Eric A.; Cederberg, Jeffrey G.

We report a semiconductor based mechanism for electrically controlling the frequency of light transmitted through extraordinary optical transmission gratings. In doing so, we demonstrate active control over the surface plasmon (SP) resonance at the metal/dielectric interface. The gratings, designed to operate in the midinfrared spectral range, are fabricated upon a doped GaAs epilayer. Tuning of over 25 cm{sup -1} is achieved, and the devices are modeled to investigate the physical origin of the tuning mechanism. Though our structures are designed for the midinfrared, the tuning mechanism demonstrated could be applied to other wavelength ranges, especially the visible and near infrared.

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Divertor and midplane materials evaluation system in DIII-D

Journal of Nuclear Materials

Wong, C.P.C.; Rudakov, D.L.; Allain, J.P.; Bastasz, Robert J.; Brooks, N.H.; Brooks, J.N.; Doerner, R.P.; Evans, T.E.; Hassanein, A.; Jacob, W.; Krieger, K.; Litnovsky, A.; McLean, A.G.; Philipps, V.; Pigarov, A.Y.; Wampler, W.R.; Watkins, J.G.; West, W.P.; Whaley, Josh A.; Wienhold, P.

The Divertor Materials Evaluation System (DiMES) at General Atomics has successfully advanced the understanding of plasma surface interaction phenomena involving ITER-relevant materials and has been utilized for advanced diagnostic designs in the lower divertor of DIII-D. This paper describes a series of recent successful experiments. These include the study of carbon deposition in gaps and metallic mirrors as a function of temperature, study of dust migration from the divertor, study of methane injection in order to benchmark chemical sputtering diagnostics, and the measurement of charge exchange neutrals with a hydrogen sensor. In concert with the modification of the lower divertor of DIII-D, the DiMES sample vertical location was modified to match the raised divertor floor. The new Mid-plane Material Exposure Sample (MiMES) design will also be presented. MiMES will allow the study and measurement of erosion and redeposition of material at the outboard mid-plane of DIII-D, including effects from convective transport. We will continue to expose relevant materials and advanced diagnostics to different plasma configurations under various operational regimes, including material erosion and redeposition experiments, and gaps and mirror exposures at elevated temperature. © 2007 Elsevier B.V. All rights reserved.

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Unit cell expansion in ErT2 films

Powder Diffraction

Rodriguez, M.A.; Browning, J.F.; Frazer, Colleen S.; Snow, Clark S.; Tissot, Ralph G.; Boespflug, Elaine P.

XRD analysis of plasma-vapor-deposited ErT2 films during aging (T decay to He3) reveals an hkl-dependent unit-cell expansion in which (200) grains expand out-of-plane as much as 0.01 Å more than (111) out-of-plane grains. Texture analysis of an aged ErT2 film reveals a bimodal (111)/(200) out-of-plane preferred orientation. Sin2 ψ analysis reveals significant in-plane macro-strain due to He3 bubble formation/growth. The mechanistic origins regarding these observations are also discussed. © 2007 International Centre for Diffraction Data.

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Stochastic spectral methods for efficient Bayesian solution of inverse problems

Journal of Computational Physics

Marzouk, Youssef M.; Najm, H.N.; Rahn, Larry A.

We present a reformulation of the Bayesian approach to inverse problems, that seeks to accelerate Bayesian inference by using polynomial chaos (PC) expansions to represent random variables. Evaluation of integrals over the unknown parameter space is recast, more efficiently, as Monte Carlo sampling of the random variables underlying the PC expansion. We evaluate the utility of this technique on a transient diffusion problem arising in contaminant source inversion. The accuracy of posterior estimates is examined with respect to the order of the PC representation, the choice of PC basis, and the decomposition of the support of the prior. The computational cost of the new scheme shows significant gains over direct sampling. © 2006 Elsevier Inc. All rights reserved.

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Pb nanoprecipitates in Al: Magic-shape effects due to elastic strain

Physical Review Letters

Hamilton, J.C.; Léonard, F.; Johnson, E.; Dahmen, U.

We present a theory for size-dependent shapes of Pb nanoprecipitates in Al, introducing the concept of "magic shapes," i.e., shapes having near-zero homogeneous elastic strains. Our quantitative atomistic calculations of edge energies show their effect on precipitate shape to be negligible, thus it appears that shapes must be due to the combined effect of strain and interface energies. By employing an algorithm for generating magic shapes, we replicate the experimental observations by selecting magic-shape precipitates with interfacial energies less than a cutoff value. © 2007 The American Physical Society.

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Measurements and Quasi-Quantum Modeling of the Steric Asymmetry and Parity Propensities in State-to-State Rotationally Inelastic Scattering of NO (2Π1/2) with D2

Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

Taatjes, Craig A.

In this paper, relative integrated cross sections are measured for spin-orbit-conserving, rotationally inelastic scattering of NO (2Π1/2), hexapole-selected in the upper Λ-doublet level of the ground rotational state (j = 0.5), in collisions with D2 at a nominal energy of 551 cm-1. The final state of the NO molecule is detected by laser-induced fluorescence (LIF). The state-selected NO molecule is oriented with either the N end or the O end toward the incoming D2 molecule by application of a static electric field E in the scattering region. This field is directed parallel or antiparallel to the relative velocity vector v. Comparison of signals taken for the different applied field directions gives the experimental steric asymmetry SA, defined by SA = (σv↑↓E - σv↑↑E)/(σv↑↓E + σv↑↑E), which is equal to within a factor of -1 to the molecular steric effect, Si→f ≡ (σD2→NO - σD2→ON)/(σD2→NO + σD2→ON). The dependence of the integral inelastic cross section on the incoming Λ-doublet component is also measured as a function of the final rotational (jfinal) and Λ-doublet (εfinal) state. The measured steric asymmetries are similar to those previously observed for NO-He scattering. Spin-orbit manifold-conserving collisions exhibit a larger propensity for parity conservation than their NO-He counterparts. The results are interpreted in the context of the recently developed quasi-quantum treatment (QQT) of rotationally inelastic scattering. The QQT predictions can be inverted to obtain a fitted hard-shell potential that reproduces the experimental steric asymmetry; this fitted potential gives an empirical estimate of the anisotropy of the repulsive interaction between NO and D2. Finally, QQT computation of the differential cross section using this simple model potential shows reasonable agreement with the measured differential cross sections.

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RADTRAN/RADCAT user guide

Weiner, Ruth F.; Mills, G.S.; O'Donnell, Brandon M.; Orcutt, David J.

RADTRAN is a program and code for calculating the risks of transporting radioactive materials. The first versions of the program, RADTRAN I and II, were developed for NUREG-0170 (USNRC, 1977), the first environmental impact statement on transportation of radioactive materials. RADTRAN and its associated software have undergone a number of improvements and advances consistent with improvements in computer technology.

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Multimegavolt laser-triggered gas switching with a green laser and beam transport through water

IEEE Transactions on Plasma Science

Zameroski, Nathan D.; Lehr, J.M.; Woodworth, Joseph R.; Blickem, Jim R.; Hodge, Keith C.; Wallace, Zachariah R.; Anaya, Victor; Corley, John P.; Lott, John A.

Ultraviolet (UV) laser-triggered gas switching using laser beams at 266 nm has greatly improved the simultaneity of many large multimodule accelerators. This UV beam however cannot be transmitted significant distances through water or oil. Since the switches in these accelerators are typically submerged in water or oil, the laser beams are often conveyed to the switches through gas-filled "laser crossover tubes."These crossover tubes are difficult to field grade properly and are subject to frequent mechanical and electrical failures in the pulse-power environment. We have demonstrated that a 4.6-MV multistage gas switch insulated with SF6 can be triggered with a jitter of less than 10 ns using 110-mJ pulses of a green (532-nm) laser beam that has been transported through 67 cm of 1-MΩcm water on its way to the switch. These results may allow elimination of the laser crossover tubes in future accelerators. © 2007 IEEE.

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Mixed convection heat transfer to and from a horizontal cylinder in cross-flow with heating from below

International Journal of Heat and Fluid Flow

Laskowski, G.M.; Kearney, S.P.; Evans, G.; Greif, R.

Heat transfer to and from a circular cylinder in a cross-flow of water at low Reynolds number was studied both experimentally and numerically. The experiments were carried out in a high aspect ratio water channel. The test section inflow temperature and velocity, channel lower surface temperature and cylinder surface temperature were controlled to yield either laminar or turbulent flow for a desired Richardson number. When the lower surface was unheated, the temperatures of the lower surface and water upstream of the cylinder were maintained approximately equal and the flow was laminar. When the lower surface was heated, turbulence intensities as high as 20% were measured several cylinder diameters upstream of the cylinder due to turbulent thermal plumes produced by heating the lower surface. Variable property, two-dimensional simulations were undertaken using a variant of the v2-f turbulence model with buoyancy production of turbulence accounted for by a simple gradient diffusion model. Predicted and measured heat flux distributions around the cylinder are compared for values of the Richardson number, Grd / Red2, from 0.3 to 9.3. For laminar flow, the predicted and measured heat flux results agreed to within the experimental uncertainty. When the lower surface was heated, and the flow was turbulent, there was qualitative agreement between predicted and measured heat flux distributions around the cylinder. However the predicted spatially averaged Nusselt number was from 37% to 53% larger than the measured spatially averaged Nusselt number. Additionally, spatially averaged Nusselt numbers are compared to correlations in the literature for mixed convection heat transfer to/from cylinders in cross-flow. The results presented here are larger than the correlation values. This is believed to be due to the effects of buoyancy-induced turbulence resulting from heating the lower surface and the proximity of the cylinder to that surface. © 2006 Elsevier Inc. All rights reserved.

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Early thermal testing of type B radioactive material packages in USA to environments beyond regulatory package thermal test standards

Packaging, Transport, Storage and Security of Radioactive Material

Three separate fire test programmes exposing casks beyond the regulatory thermal test requirements were performed by Sandia National Laboratories during the late 1970s and mid 1980s. The results of these test programmes can be used to assist in addressing the adequacy of the regulatory thermal test of fully engulfing exposure at 800°C for 30 min and how that test might relate to real accident thermal environments. The test programmes were undertaken on obsolete and new casks on behalf of the US Department of Energy (DOE), the US Department of Transportation (DOT) and the Japanese Power Reactor and Nuclear Fuel Development Corporation (PNC), currently known as the Japan Atomic Energy Agency. Two of the tests involved exposure of casks in damaged transport vehicles to fully engulfing fires for 72–125 min, and the other test involved four exposures of a cask to torch environments for 30 min. Much of the original documentation regarding these tests and their results is no longer readily available. The documents relating to these tests have been surveyed; this paper presents summaries from this survey of the tests and their results. Specifically, for the pool fire exposures, the temperatures measured in the flames of both exceeded the flame temperature required by the Transport Regulations; yet an obsolete 67 t cask endured 90 min of exposure before evidence of failure was detected, and a new cask endured the 72 min exposure while retaining its containment integrity. For the exposure of a modified obsolete cask to four different torch environments, the integrity of the cask was retained and the relative temperature increases within the cask were well within acceptable limits and well below the values that could be expected if the cask was exposed to the regulatory thermal test. In this paper, a review of these three thermal test programmes, establishes that the two older cask designs and one new cask design have the ability to survive environments that were different from (the torch environments) or more severe than the environment specified by the existing thermal test requirement in the Transport Regulations. Finally, these results can be extrapolated to apply to modern casks that generally have more robust designs as well as better quality assurance applied during the manufacturing process.

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Planar LTCC transformers for high voltage flyback converters

Roesler, Alexander R.; Schare, Joshua M.; Ewsuk, Kevin G.; Glass, Sarah J.

This paper discusses the design and use of low-temperature (850 C to 950 C) co-fired ceramic (LTCC) planar magnetic flyback transformers for applications that require conversion of a low voltage to high voltage (> 100V) with significant volumetric constraints. Measured performance and modeling results for multiple designs showed that the LTCC flyback transformer design and construction imposes serious limitations on the achievable coupling and significantly impacts the transformer performance and output voltage. This paper discusses the impact of various design factors that can provide improved performance by increasing transformer coupling and output voltage. The experiments performed on prototype units demonstrated LTCC transformer designs capable of greater than 2 kV output. Finally, the work investigated the effect of the LTCC microstructure on transformer insulation. Although this paper focuses on generating voltages in the kV range, the experimental characterization and discussion presented in this work applies to designs requiring lower voltage.

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Site environmental report for 2006 Sandia National Laboratories, California

Larsen, Barbara L.

Sandia National Laboratories, California (SNL/CA) is a government-owned/contractor-operated laboratory. Sandia Corporation, a Lockheed Martin Company, operates the laboratory for the Department of Energy's National Nuclear Security Administration (NNSA). The NNSA Sandia Site Office oversees operations at the site, using Sandia Corporation as a management and operating contractor. This Site Environmental Report for 2006 was prepared in accordance with DOE Order 231.1A (DOE 2004a). The report provides a summary of environmental monitoring information and compliance activities that occurred at SNL/CA during calendar year 2006. General site and environmental program information is also included.

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Benchmark enclosure fire suppression experiments - phase 1 test report

Figueroa Faria, Victor G.

A series of fire benchmark water suppression tests were performed that may provide guidance for dispersal systems for the protection of high value assets. The test results provide boundary and temporal data necessary for water spray suppression model development and validation. A review of fire suppression in presented for both gaseous suppression and water mist fire suppression. The experimental setup and procedure for gathering water suppression performance data are shown. Characteristics of the nozzles used in the testing are presented. Results of the experiments are discussed.

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Heliostat cost reduction study

Jones, S.A.; Donnelly, Mathew W.; Kolb, Gregory J.

Power towers are capable of producing solar-generated electricity and hydrogen on a large scale. Heliostats are the most important cost element of a solar power tower plant. Since they constitute {approx} 50% of the capital cost of the plant it is important to reduce heliostat cost as much as possible to improve the economic performance of power towers. In this study we evaluate current heliostat technology and estimate a price of $126/m{sup 2} given year-2006 materials and labor costs for a deployment of {approx}600 MW of power towers per year. This 2006 price yields electricity at $0.067/kWh and hydrogen at $3.20/kg. We propose research and development that should ultimately lead to a price as low as $90/m{sup 2}, which equates to $0.056/kWh and $2.75/kg H{sup 2}. Approximately 30 heliostat and manufacturing experts from the United States, Europe, and Australia contributed to the content of this report during two separate workshops conducted at the National Solar Thermal Test Facility.

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Wetting and free surface flow modeling for potting and encapsulation

Adolf, Douglas B.; Castaneda, Jaime N.; Kraynik, Andrew M.; Noble, David R.; Sun, Amy C.; Cote, Raymond O.; Grillet, Anne M.; Notz, Patrick N.; Brooks, Carlton F.; Givler, R.C.; Hopkins, Matthew M.; Mondy, L.A.; Rao, Rekha R.

As part of an effort to reduce costs and improve quality control in encapsulation and potting processes the Technology Initiative Project ''Defect Free Manufacturing and Assembly'' has completed a computational modeling study of flows representative of those seen in these processes. Flow solutions are obtained using a coupled, finite-element-based, numerical method based on the GOMA/ARIA suite of Sandia flow solvers. The evolution of the free surface is solved with an advanced level set algorithm. This approach incorporates novel methods for representing surface tension and wetting forces that affect the evolution of the free surface. In addition, two commercially available codes, ProCAST and MOLDFLOW, are also used on geometries representing encapsulation processes at the Kansas City Plant. Visual observations of the flow in several geometries are recorded in the laboratory and compared to the models. Wetting properties for the materials in these experiments are measured using a unique flowthrough goniometer.

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A user's guide for INPAGF_Launcher.DLL

Mattie, Patrick D.

Sandia National Laboratories (Sandia), a U.S. Department of Energy National Laboratory, has over 30 years experience in the assessment of radioactive waste disposal and at the time of this publication is providing assistance internationally in a number of areas relevant to the safety assessment of radioactive waste disposal systems. In cooperation with the Republic of Taiwan's Institute of Nuclear Engineering and Research (INER), Sandia National Laboratories (SNL) has developed software that provides an interface between a deterministic far field mass transport code and GoldSim (a commercial software used to conduct Monte Carlo analyses). The SNL developed software enables INER to perform probabilistic simulations for safety analysis and performance assessment of geologic disposal of commercial spent nuclear fuel. The following report details the software design, the steps necessary to use the software, and presents an example application of the paradigm of coupling deterministic codes to a contemporary probabilistic software application.

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A User’s Guide for INPAGN_Launcher.DLL

Mattie, Patrick D.; Kalinich, Donald A.

Sandia National Laboratories (Sandia), a U.S. Department of Energy National Laboratory, has over 30 years experience in the assessment of radioactive waste disposal, and at the time of this publication is providing assistance internationally in a number of areas relevant to the safety assessment of radioactive waste disposal systems. In cooperation with the Republic of Taiwan’s Institute of Nuclear Engineering and Research (INER), Sandia National Laboratories (SNL) has developed software that provides an interface between a deterministic mass transport code and GoldSim™ (a commercial software used to conduct Monte Carlo analyses). The SNL-developed software enables INER to perform probabilistic simulations for safety analysis and performance assessment of geologic disposal of commercial spent nuclear fuel. This report details the software design, the steps necessary to use the software, and presents an example application of the paradigm of coupling deterministic codes to a contemporary probabilistic software application.

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Pollution prevention opportunity assessment for organization 1700

Gerard, Morgan E.

This Pollution Prevention Opportunity Assessment (PPOA) was conducted for Sandia National Laboratories/New Mexico Organization 1700 in June, 2006. The primary purpose of this PPOA is to provide recommendations to assist Organization 1700 in reducing the generation of waste and improving the efficiency of their processes and procedures. This report contains a summary of the information collected, analyses performed and recommended options for implementation. The Sandia National Laboratories Pollution Prevention staff will continue to work with Organization 1700 to implement the recommendations.

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Suppression of pool fires with HRC-125 in a simulated engine nacelle

Hewson, John C.

CFD simulations are conducted to predict the distribution of fire suppressant in an engine nacelle and to predict the suppression of pool fires by the application of this suppressant. In the baseline configuration, which is based on an installed system, suppressant is injected through four nozzles at a rate fast enough to suppress all simulated pool fires. Variations that reduce the mass of the suppression system (reducing the impact of the suppression system on meeting mission needs) are considered, including a reduction in the rate of suppressant injection, a reduction in the mass of suppressant and a reduction in the number of nozzles. In general, these variations should work to reduce the effectiveness of the suppression system, but the CFD results point out certain changes that have negligible impact, at least for the range of phenomena considered here. The results are compared with measurements where available. Comparisons with suppressant measurements are reasonable. A series of twenty-three fire suppression tests were conducted to check the predictions. The pre-test predictions were generally successful in identifying the range of successful suppression tests. In two separate cases, each where one nozzle of the suppression system was capped, the simulation results did indicate a failure to suppress for a condition where the tests indicated successful suppression. When the test-suppressant discharge rate was reduced by roughly 25%, the tests were in agreement with the predictions. That is, the simulations predict a failure to suppress slightly before observed in these cases.

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A resolution analysis of two geophysical imaging methods for characterizing and monitoring hydrologic conditions in the Vadose zone

Brainard, James R.; Hammond, Gary; Alumbaugh, David L.; La Brecque, D.J.

This research project analyzed the resolution of two geophysical imaging techniques, electrical resistivity tomography (ERT) and cross-borehole ground penetrating radar (XBGPR), for monitoring subsurface flow and transport processes within the vadose zone. The study was based on petrophysical conversion of moisture contents and solute distributions obtained from unsaturated flow forward modeling. This modeling incorporated boundary conditions from a potable water and a salt tracer infiltration experiment performed at the Sandia-Tech Vadose Zone (STVZ) facility, and high-resolution spatial grids (6.25-cm spacing over a 1700-m domain) and incorporated hydraulic properties measured on samples collected from the STVZ. The analysis process involved petrophysical conversion of moisture content and solute concentration fields to geophysical property fields, forward geophysical modeling using the geophysical property fields to obtain synthetic geophysical data, and finally, inversion of this synthetic data. These geophysical property models were then compared to those derived from the conversion of the hydrologic forward modeling to provide an understanding of the resolution and limitations of the geophysical techniques.

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Installation of the first Distributed Energy Storage System (DESS) at American Electric Power (AEP)

Nourai, Ali

AEP studied the direct and indirect benefits, strengths, and weaknesses of distributed energy storage systems (DESS) and chose to transform its entire utility grid into a system that achieves optimal integration of both central and distributed energy assets. To that end, AEP installed the first NAS battery-based, energy storage system in North America. After one year of operation and testing, AEP has concluded that, although the initial costs of DESS are greater than conventional power solutions, the net benefits justify the AEP decision to create a grid of DESS with intelligent monitoring, communications, and control, in order to enable the utility grid of the future. This report details the site selection, construction, benefits and lessons learned of the first installation, at Chemical Station in North Charleston, WV.

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Results 79401–79600 of 96,771
Results 79401–79600 of 96,771