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Analyses in Support of Risk-Informed Natural Gas Vehicle Maintenance Facility Codes and Standards: Phase I

Lafleur, Angela (Chris); Blaylock, Myra L.

Safety standards development for maintenance facilities of liquid and compressed gas fueled large-scale vehicles is required to ensure proper facility design and operation envelopes. Standard development organizations are utilizing risk-informed concepts to develop natural gas vehicle (NGV) codes and standards so that maintenance facilities meet acceptable risk levels. The present report summarizes Phase I work for existing NGV repair facility code requirements and highlights inconsistencies that need quantitative analysis into their effectiveness. A Hazardous and Operability study was performed to identify key scenarios of interest. Finally, scenario analyses were performed using detailed simulations and modeling to estimate the overpressure hazards from HAZOP defined scenarios. The results from Phase I will be used to identify significant risk contributors at NGV maintenance facilities, and are expected to form the basis for follow-on quantitative risk analysis work to address specific code requirements and identify effective accident prevention and mitigation strategies.

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TYPE SAND Report YEAR 2014
DOIOSTI

A Method for the Quantification of Model Form Error Associated with Physical Systems

Brake, M.R.W.

In the process of model validation, models are often declared valid when the differences between model predictions and experimental data sets are satisfactorily small. However, little consideration is given to the effectiveness of a model using parameters that deviate slightly from those that were fitted to data, such as a higher load level. Furthermore, few means exist to compare and choose between two or more models that reproduce data equally well. These issues can be addressed by analyzing model form error, which is the error associated with the differences between the physical phenomena captured by models and that of the real system. This report presents a new quantitative method for model form error analysis and applies it to data taken from experiments on tape joint bending vibrations. Two models for the tape joint system are compared, and suggestions for future improvements to the method are given. As the available data set is too small to draw any statistical conclusions, the focus of this paper is the development of a methodology that can be applied to general problems.

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TYPE SAND Report YEAR 2014
DOIOSTI

XyceTM Parallel Electronic Simulator Users’ Guide, Version 6.1

Keiter, Eric R.; Mei, Ting; Russo, Thomas V.; Schiek, Richard; 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); and 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 2014
DOIOSTI

XyceTM Parallel Electronic Simulator Reference Guide, Version 6.1

Keiter, Eric R.; Mei, Ting; Russo, Thomas V.; Schiek, Richard; 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. 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 2014
DOIOSTI

Optimality conditions for the numerical solution of optimization problems with PDE constraints: Theoretical framework and applications to parameter identification and optimal control problems

Valentin, Miguel A.; Ridzal, Denis

A theoretical framework for the numerical solution of partial differential equation (PDE) constrained optimization problems is presented in this report. This theoretical framework embodies the fundamental infrastructure required to efficiently implement and solve this class of problems. Detail derivations of the optimality conditions required to accurately solve several parameter identification and optimal control problems are also provided in this report. This will allow the reader to further understand how the theoretical abstraction presented in this report translates to the application.

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TYPE SAND Report YEAR 2014
DOIOSTI

Ignition of THKP and TKP Pyrotechnic Powders: Incorporating Reactive Chemical Processes into Predictive Models

Erikson, William W.; Wiese-Smith, Deneille; Highley, Aaron M.

We have conducted Simultaneous Thermogravimetric Modulated Beam Mass Spectrometry (STMBMS) experiments on igniter/actuator pyrotechnic powders to characterize the reactive processes controlling the ignition and combustion behavior of these materials. The experiments showed a complex, interactive reaction manifold involving over ten reaction pathways. A reduced dimensionality reaction manifold was developed from the detailed 10-step manifold and is being incorporated into existing predictive modeling codes to simulate the performance of pyrotechnic powders for NW component development. The results from development of the detailed reaction manifold and reduced manifold are presented. The reduced reaction manifold has been successfully used by SNL/NM modelers to predict thermal ignition events in small-scale testing, validating our approach and improving the capability of predictive models.

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TYPE SAND Report YEAR 2014
DOIOSTI

Information findability: An informal study to explore options for improving information findability for the systems analysis group

Stoecker, Nora K.

A Systems Analysis Group has existed at Sandia National Laboratories since at least the mid-1950s. Much of the groups work output (reports, briefing documents, and other materials) has been retained, along with large numbers of related documents. Over time the collection has grown to hundreds of thousands of unstructured documents in many formats contained in one or more of several different shared drives or SharePoint sites, with perhaps five percent of the collection still existing in print format. This presents a challenge. How can the group effectively find, manage, and build on information contained somewhere within such a large set of unstructured documents? In response, a project was initiated to identify tools that would be able to meet this challenge. This report documents the results found and recommendations made as of August 2013.

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TYPE SAND Report YEAR 2014
DOIOSTI

System Dynamics of the Competition of Municipal Solid Waste to Landfill, Electricity, and Liquid Fuel in California

Malczynski, Leonard A.; Manley, Dawn K.

A quantitative system dynamics model was created to evaluate the economic and environmental tradeoffs between biomass to electricity and to liquid fuel using MSW biomass in the state of California as a case study. From an environmental perspective, landfilling represents the worst use of MSW over time, generating more greenhouse gas (GHG) emissions compared to converting MSW to liquid fuel or to electricity. MSW to ethanol results in the greatest displacement of GHG emissions per dollar spent compared to MSW to electricity. MSW to ethanol could save the state of California approximately $60 billion in energy costs by 2050 compared to landfilling, while also reducing GHG emissions state-wide by approximately 140 million metric tons during that timeframe. MSW conversion to electricity creates a significant cost within the state's electricity sector, although some conversion technologies are cost competitive with existing renewable generation.

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TYPE SAND Report YEAR 2014
DOIOSTI
Results 53901–54000 of 99,299
Results 53901–54000 of 99,299