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Heavy Duty Vehicle Futures Analysis

Askin, Amanda C.; Barter, Garrett E.; West, Todd H.; Manley, Dawn K.

This report describes work performed for an Early Career Research and Development project. This project developed a heavy-duty vehicle (HDV) sector model to assess the factors influencing alternative fuel and efficiency technology adoption. This model builds on a Sandia light duty vehicle sector model and provides a platform for assessing potential impacts of technological advancements developed at the Combustion Research Facility. Alternative fuel and technology adoption modeling is typically developed around a small set of scenarios. This HDV sector model segments the HDV sector and parameterizes input values, such as fuel prices, efficiencies, and vehicle costs. This parameterization enables sensitivity and trade space analyses to identify the inputs that are most associated with outputs of interest, such as diesel consumption and greenhouse gas emissions. Thus this analysis tool enables identification of the most significant HDV sector drivers that can be used to support energy security and climate change goals.

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TYPE SAND Report YEAR 2014
DOIOSTI

Evaluation of three refurbished Guralp CMG-3TB seismometers

Merchant, Bion J.

The overall objective of testing the Guralp CMG-3TB refurbished seismometers is to determine whether or not the refurbished sensors exhibit better data quality and require less maintenance when deployed than the original Guralp CMG-3TBs. SNL will test these 3 refurbished Guralps to verify performance specifications. The specifications that will be evaluated are sensitivity, bandwidth, self-noise, output impedance, clip-level, dynamic range over application passband, verify mathematical response and calibration response parameters for amplitude and phase.

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TYPE SAND Report YEAR 2014
DOIOSTI

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

Adams, Brian M.; Jakeman, John D.; Swiler, Laura P.; Stephens, John A.; Vigil, Dena; Wildey, Timothy; Bauman, Lara E.; Bohnhoff, William J.; Dalbey, Keith; Eddy, John P.; Ebeida, Mohamed; Eldred, Michael; Hough, Patricia D.; Hu, Kenneth

The Dakota (Design Analysis Kit for Optimization and Terascale Applications) toolkit provides a exible and extensible interface between simulation codes and iterative analysis methods. Dakota contains algorithms for optimization with gradient and nongradient-based methods; uncertainty quanti cation 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 exible and extensible problem-solving environment for design and performance analysis of computational models on high performance computers. This report serves as a user's manual for the Dakota software and provides capability overviews and procedures for software execution, as well as a variety of example studies.

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TYPE SAND Report YEAR 2014
DOIOSTI

Reduced Order Modeling for Prediction and Control of Large-Scale Systems

Tezaur, Irina K.; Arunajatesan, Srinivasan; Barone, Matthew F.; Van Bloemen Waanders, Bart; Fike, Jeffrey

This report describes work performed from June 2012 through May 2014 as a part of a Sandia Early Career Laboratory Directed Research and Development (LDRD) project led by the first author. The objective of the project is to investigate methods for building stable and efficient proper orthogonal decomposition (POD)/Galerkin reduced order models (ROMs): models derived from a sequence of high-fidelity simulations but having a much lower computational cost. Since they are, by construction, small and fast, ROMs can enable real-time simulations of complex systems for onthe- spot analysis, control and decision-making in the presence of uncertainty. Of particular interest to Sandia is the use of ROMs for the quantification of the compressible captive-carry environment, simulated for the design and qualification of nuclear weapons systems. It is an unfortunate reality that many ROM techniques are computationally intractable or lack an a priori stability guarantee for compressible flows. For this reason, this LDRD project focuses on the development of techniques for building provably stable projection-based ROMs. Model reduction approaches based on continuous as well as discrete projection are considered. In the first part of this report, an approach for building energy-stable Galerkin ROMs for linear hyperbolic or incompletely parabolic systems of partial differential equations (PDEs) using continuous projection is developed. The key idea is to apply a transformation induced by the Lyapunov function for the system, and to build the ROM in the transformed variables. It is shown that, for many PDE systems including the linearized compressible Euler and linearized compressible Navier-Stokes equations, the desired transformation is induced by a special inner product, termed the “symmetry inner product”. Attention is then turned to nonlinear conservation laws. A new transformation and corresponding energy-based inner product for the full nonlinear compressible Navier-Stokes equations is derived, and it is demonstrated that if a Galerkin ROM is constructed in this inner product, the ROM system energy will be bounded in a way that is consistent with the behavior of the exact solution to these PDEs, i.e., the ROM will be energy-stable. The viability of the linear as well as nonlinear continuous projection model reduction approaches developed as a part of this project is evaluated on several test cases, including the cavity configuration of interest in the targeted application area. In the second part of this report, some POD/Galerkin approaches for building stable ROMs using discrete projection are explored. It is shown that, for generic linear time-invariant (LTI) systems, a discrete counterpart of the continuous symmetry inner product is a weighted L2 inner product obtained by solving a Lyapunov equation. This inner product was first proposed by Rowley et al., and is termed herein the “Lyapunov inner product“. Comparisons between the symmetry inner product and the Lyapunov inner product are made, and the performance of ROMs constructed using these inner products is evaluated on several benchmark test cases. Also in the second part of this report, a new ROM stabilization approach, termed “ROM stabilization via optimization-based eigenvalue reassignment“, is developed for generic LTI systems. At the heart of this method is a constrained nonlinear least-squares optimization problem that is formulated and solved numerically to ensure accuracy of the stabilized ROM. Numerical studies reveal that the optimization problem is computationally inexpensive to solve, and that the new stabilization approach delivers ROMs that are stable as well as accurate. Summaries of “lessons learned“ and perspectives for future work motivated by this LDRD project are provided at the end of each of the two main chapters.

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TYPE SAND Report YEAR 2014
DOIOSTI

Advancing cyber resilience analysis with performance- based metrics from infrastructure assessments

Cyber Behavior: Concepts, Methodologies, Tools, and Applications

Vugrin, Eric; Turgeon, Jennifer

Cyber resilience is becoming increasingly recognized as a critical component of comprehensive cybersecurity practices. Current cyber resilience assessment approaches are primarily qualitative methods, making validation of their resilience analyses and enhancement recommendations difficult, if not impossible. The evolution of infrastructure resilience assessment methods has paralleled that of their cyber counterparts. However, the development of performance-based assessment methods has shown promise for overcoming the validation challenge for infrastructure systems. This article describes a hybrid infrastructure resilience assessment approach that combines both qualitative analysis techniques with performance-based metrics. The qualitative component enables identification of system features that limit resilience, and the quantitative metrics can be used to evaluate and confirm the effectiveness of proposed mitigation options. The authors propose adaptation of this methodology for cyber resilience analysis. A case study is presented to demonstrate how the approach could be applied to a hypothetical system.

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TYPE Journal Article YEAR 2014
OSTIScopus

SEGR in SiO${}_2$ –Si$_3$ N$_4$ Stacks

IEEE Transactions on Nuclear Science

Schwank, James R.; Shaneyfelt, Marty R.

This work presents experimental SEGR data for MOS-devices, where the gate dielectrics are are made of stacked SiO2–Si3N4 structures. Also a semi-empirical model for predicting the critical gate voltage in these structures under heavy-ion exposure is proposed. Then statistical interrelationship between SEGR cross-section data and simulated energy deposition probabilities in thin dielectric layers is discussed.

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TYPE Journal Article YEAR 2014
OSTIDOI

Vibrational analysis of brucite surfaces and the development of an improved force field for molecular simulation of interfaces

Journal of Physical Chemistry C

Zeitler, Todd R.; Greathouse, Jeffery A.; Gale, Julian D.; Cygan, Randall T.

We introduce a nonbonded three-body harmonic potential energy term for Mg-O-H interactions for improved edge surface stability in molecular simulations. The new potential term is compatible with the Clayff force field and is applied here to brucite, a layered magnesium hydroxide mineral. Comparisons of normal mode frequencies from classical and density functional theory calculations are used to verify a suitable spring constant (k parameter) for the Mg-O-H bending motion. Vibrational analysis of hydroxyl librations at two brucite surfaces indicates that surface Mg-O-H modes are shifted to frequencies lower than the corresponding bulk modes. A comparison of DFT and classical normal modes validates this new potential term. The methodology for parameter development can be applied to other clay mineral components (e.g., Al, Si) to improve the modeling of edge surface stability, resulting in expanded applicability to clay mineral applications. © 2014 American Chemical Society.

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TYPE Journal Article YEAR 2014
ScopusOSTI

Non-ordinary state-based peridynamic analysis of stationary crack problems

Computer Methods in Applied Mechanics and Engineering

Breitenfeld, M.S.; Geubelle, P.H.; Weckner, O.; Silling, S.A.

An implicit implementation of the non-ordinary state-based peridynamics formulation for quasi-static linearly elastic solids is presented. Emphasis is placed on assessing the accuracy of the numerical scheme in the vicinity of the crack front and other sources of stress concentration. We also present a comparative study of methods used to control the zero-energy modes inherent in the nonlocal definition of the strain tensor and reduce the spurious oscillations present particularly in regions of high strain gradients. The accuracy of the peridynamics scheme, including the impact of the lattice spacing and configuration, is assessed by performing an analysis of the near-tip stress and displacement fields (K-fields) for 2D problems. The manuscript also summarizes a verification study based on the classical 3D penny-shaped crack problem and a validation study of a 3D notched fracture specimen. © 2014 Elsevier B.V.

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TYPE Journal Article YEAR 2014
ScopusOSTI

Instant gelation synthesis of 3D porous MoS2@C nanocomposites for lithium ion batteries

Nanoscale

Fei, Ling; Xu, Yun; Wu, Xiaofei; Chen, Gen; Li, Yuling; Li, Binsong; Deng, Shuguang; Smirnov, Sergei; Fan, Hongyou; Luo, Hongmei

Three-dimensional (3D) nanoporous architectures, possessing high surface area, massive pores, and excellent structural stability, are highly desirable for many applications including catalysts and electrode materials in lithium ion batteries. However, the preparation of such materials remains a major challenge. Here, we introduce a novel method, instant gelation, for the synthesis of such materials. The as-prepared porous 3D MoS2@C nanocomposites, with layered MoS2 clusters or strips ingrained in porous and conductive 3D carbon matrix, indeed showed excellent electrochemical performance when applied as anode materials for lithium ion batteries. Its interconnected carbon network ensures good conductivity and fast electron transport; the micro-, and mesoporous nature effectively shortens the lithium ion diffusion path and provides room necessary for volume expansion. The large specific surface area is beneficial for a better contact between electrode materials and electrolyte. This journal is © the Partner Organisations 2014.

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TYPE Journal Article YEAR 2014
ScopusOSTIDOI

A Bayesian method for using simulator data to enhance human error probabilities assigned by existing HRA methods

Reliability Engineering and System Safety

Groth, Katrina M.; Swiler, Laura P.; Adams, Susan S.

In the past several years, several international agencies have begun to collect data on human performance in nuclear power plant simulators [1]. This data provides a valuable opportunity to improve human reliability analysis (HRA), but there improvements will not be realized without implementation of Bayesian methods. Bayesian methods are widely used in to incorporate sparse data into models in many parts of probabilistic risk assessment (PRA), but Bayesian methods have not been adopted by the HRA community. In this article, we provide a Bayesian methodology to formally use simulator data to refine the human error probabilities (HEPs) assigned by existing HRA methods. We demonstrate the methodology with a case study, wherein we use simulator data from the Halden Reactor Project to update the probability assignments from the SPAR-H method. The case study demonstrates the ability to use performance data, even sparse data, to improve existing HRA methods. Furthermore, this paper also serves as a demonstration of the value of Bayesian methods to improve the technical basis of HRA.

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TYPE Journal Article YEAR 2014
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Anisotropic radiation-induced segregation in 316L austenitic stainless steel with grain boundary character

Acta Materialia

Barr, Christopher M.; Vetterick, Gregory A.; Unocic, Kinga A.; Hattar, Khalid M.; Bai, Xian M.; Taheri, Mitra L.

Radiation-induced segregation (RIS) and subsequent depletion of chromium along grain boundaries has been shown to be an important factor in irradiation-assisted stress corrosion cracking in austenitic face-centered cubic (fcc)-based alloys used for nuclear energy systems. A full understanding of RIS requires examination of the effect of the grain boundary character on the segregation process. Understanding how specific grain boundary structures respond under irradiation would assist in developing or designing alloys that are more efficient at removing point defects, or reducing the overall rate of deleterious Cr segregation. This study shows that solute segregation is dependent not only on grain boundary misorientation, but also on the grain boundary plane, as highlighted by markedly different segregation behavior for the Σ3 incoherent and coherent grain boundaries. The link between RIS and atomistic modeling is also explored through molecular dynamic simulations of the interaction of vacancies at different grain boundary structures through defect energetics in a simple model system. A key insight from the coupled experimental RIS measurements and corresponding defect-grain boundary modeling is that grain boundary-vacancy formation energy may have a critical threshold value related to the major alloying elements' solute segregation. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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TYPE Journal Article YEAR 2014
ScopusOSTI

Fusion-neutron-yield, activation measurements at the Z accelerator: Design, analysis, and sensitivity

Review of Scientific Instruments

Hahn, Kelly; Ruiz, Carlos L.; Chandler, Gordon A.; Knapp, P.F.; Smelser, Ruth

We present a general methodology to determine the diagnostic sensitivity that is directly applicable to neutron-activation diagnostics fielded on a wide variety of neutron-producing experiments, which include inertial-confinement fusion (ICF), dense plasma focus, and ion beam-driven concepts. This approach includes a combination of several effects: (1) non-isotropic neutron emission; (2) the 1/r2 decrease in neutron fluence in the activation material; (3) the spatially distributed neutron scattering, attenuation, and energy losses due to the fielding environment and activation material itself; and (4) temporally varying neutron emission. As an example, we describe the copper-activation diagnostic used to measure secondary deuterium-tritium fusion-neutron yields on ICF experiments conducted on the pulsed-power Z Accelerator at Sandia National Laboratories. Using this methodology along with results from absolute calibrations and Monte Carlo simulations, we find that for the diagnostic configuration on Z, the diagnostic sensitivity is 0.037% ± 17% counts/neutron per cm2 and is ~ 40% less sensitive than it would be in an ideal geometry due to neutron attenuation, scattering, and energy-loss effects.

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TYPE Journal Article YEAR 2014
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The perfect heist :

Lafleur, Jarret M.; Purvis, Liston K.; Roesler, Alexander

Of the many facets of the criminal world, few have captured societys fascination as has that of high stakes robbery. The combination of meticulousness, cunning, and audacity required to execute a real-life Oceans Eleven may be uncommon among criminals, but fortunately it is common enough to extract a wealth of lessons for the protection of high-value assets. To assist in informing the analyses and decisions of security professionals, this paper surveys 23 sophisticated and high-value heists that have occurred or been attempted around the world, particularly over the past three decades. The results, compiled in a Heist Methods and Characteristics Database, have been analyzed qualitatively and quantitatively, with the goals of both identifying common characteristics and characterizing the range and diversity of criminal methods used. The analysis is focused in six areas: (1) Defeated Security Measures and Devices, (2) Deception Methods, (3) Timing, (4) Weapons, (5) Resources, and (6) Insiders.

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TYPE SAND Report YEAR 2014
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Cooperative measures to support the Indo-Pak Agreement Reducing Risk from Accidents Relating to Nuclear Weapons

Mishra, Sitakanta; Ahmed, Mansoor

In 2012, India and Pakistan reaffirmed the Agreement on Reducing the Risk from Accidents Relating to Nuclear Weapons. Despite a history of mutual animosity and persistent conflict between the two countries, this agreement derives strength from a few successful nuclear confidence building measures that have stood the test of time. It also rests on the hope that the region would be spared a nuclear holocaust from an accidental nuclear weapon detonation that might be misconstrued as a deliberate use of a weapon by the other side. This study brings together two emerging strategic analysts from South Asia to explore measures to support the Agreement and further develop cooperation around this critical issue. This study briefly dwells upon the strategic landscape of nuclear South Asia with the respective nuclear force management structures, doctrines, and postures of India and Pakistan. It outlines the measures in place for the physical protection and safety of nuclear warheads, nuclear materials, and command and control mechanisms in the two countries, and it goes on to identify the prominent, emerging challenges posed by the introduction of new weapon technologies and modernization of the respective strategic forces. This is followed by an analysis of the agreement itself leading up to a proposed framework for cooperative measures that might enhance the spirit and implementation of the agreement.

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TYPE SAND Report YEAR 2014
DOIOSTI

Review of Inputs Provided to Jason Associates Corporation in Support of RWEV-REP-001, the Analysis of Postclosure Groundwater Impacts Report

Bryan, C.R.; Weck, Philippe F.; Vaughn, Palmer; Arnold, Bill W.

Report RWEV-REP-001, Analysis of Postclosure Groundwater Impacts for a Geologic Repository for the Disposal of Spent Nuclear Fuel and High Level Radioactive Waste at Yucca Mountain, Nye County, Nevada was issued by the DOE in 2009 and is currently being updated. Sandia National Laboratories (SNL) provided support for the original document, performing calculations and extracting data from the Yucca Mountain Performance Assessment Model that were used as inputs to the contaminant transport and dose calculations by Jason Associates Corporation, the primary developers of the DOE report. The inputs from SNL were documented in LSA-AR-037, Inputs to Jason Associates Corporation in Support of the Postclosure Repository Supplemental Environmental Impact Statement. To support the updating of the original Groundwater Impacts document, SNL has reviewed the inputs provided in LSA-AR-037 to verify that they are current and appropriate for use. The results of that assessment are documented here.

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TYPE SAND Report YEAR 2014
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Determine Minimum Silver Flake Addition to GCM for Iodine Loaded AgZ

Garino, Terry J.; Nenoff, Tina M.; Rodriguez, Marko A.

The minimum amount of silver flake required to prevent loss of I{sub 2} during sintering in air for a SNL Glass Composite Material (GCM) Waste Form containing AgI-MOR (ORNL, 8.7 wt%) was determined to be 1.1 wt% Ag. The final GCM composition prior to sintering was 20 wt% AgI-MOR, 1.1 wt% Ag, and 80 wt% Bi-Si oxide glass. The amount of silver flake needed to suppress iodine loss was determined using thermo gravimetric analysis with mass spectroscopic off-gas analysis. These studies found that the ratio of silver to AgI-MOR required is lower in the presence of the glass than without it. Therefore an additional benefit of the GCM is that it serves to inhibit some iodine loss during processing. Alternatively, heating the AgI-MOR in inert atmosphere instead of air allowed for densified GCM formation without I{sub 2} loss, and no necessity for the addition of Ag. The cause of this behavior is found to be related to the oxidation of the metallic Ag to Ag{sup +} when heated to above ~300{degrees}C in air. Heating rate, iodine loading levels and atmosphere are the important variables that determine AgI migration and results suggest that AgI may be completely incorporated into the mordenite structure by the 550{degrees}C sintering temperature.

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TYPE Presentation YEAR 2014
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Results 53201–53400 of 99,299
Results 53201–53400 of 99,299