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Proceedings of the Scientific Visit on Crystalline Rock Repository Development

Mariner, Paul; Hardin, Ernest

A scientific visit on Crystalline Rock Repository Development was held in the Czech Republic on September 24-27, 2012. The visit was hosted by the Czech Radioactive Waste Repository Authority (RAWRA), co-hosted by Sandia National Laboratories (SNL), and supported by the International Atomic Energy Agency (IAEA). The purpose of the visit was to promote technical information exchange between participants from countries engaged in the investigation and exploration of crystalline rock for the eventual construction of nuclear waste repositories. The visit was designed especially for participants of countries that have recently commenced (or recommenced) national repository programmes in crystalline host rock formations. Discussion topics included repository programme development, site screening and selection, site characterization, disposal concepts in crystalline host rock, regulatory frameworks, and safety assessment methodology. Interest was surveyed in establishing a "club", the mission of which would be to identify and address the various technical challenges that confront the disposal of radioactive waste in crystalline rock environments. The idea of a second scientific visit to be held one year later in another host country received popular support. The visit concluded with a trip to the countryside south of Prague where participants were treated to a tour of the laboratory and underground facilities of the Josef Regional Underground Research Centre.

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TYPE SAND Report YEAR 2013
DOIOSTI

Detailed measurements of thread deformation and failure in thin walled aluminum alloy joints

Conference Proceedings of the Society for Experimental Mechanics Series

Antoun, Bonnie R.; Grange, Spencer; Wellman, Gerald W.; Dempsey, J.F.

This paper describes the development and implementation of the experimental design, apparatus and measurement methods for quantifying the deformation of threads during loading to failure. A linear thread geometry is used to allow direct optical and contacting measurements of key displacements along the loading axis and across the threaded engagement section. Full field optical measurements of thread pairs are collected for post-processing using digital image correlation methods. Thread geometry parameters and material pairings are studied. © The Society for Experimental Mechanics, Inc. 2013.

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TYPE Conference YEAR 2013
ScopusOSTI

Unconventional peroxy chemistry in alcohol oxidation: The water elimination pathway

Journal of Physical Chemistry Letters

Welz, Oliver W.; Klippenstein, Stephen J.; Harding, Lawrence B.; Taatjes, Craig A.; Zador, Judit

Predictive simulation for designing efficient engines requires detailed modeling of combustion chemistry, for which the possibility of unknown pathways is a continual concern. Here, we characterize a low-lying water elimination pathway from key hydroperoxyalkyl (QOOH) radicals derived from alcohols. The corresponding saddle-point structure involves the interaction of radical and zwitterionic electronic states. This interaction presents extreme difficulties for electronic structure characterizations, but we demonstrate that these properties of this saddle point can be well captured by M06-2X and CCSD(T) methods. Experimental evidence for the existence and relevance of this pathway is shown in recently reported data on the low-temperature oxidation of isopentanol and isobutanol. In these systems, water elimination is a major pathway, and is likely ubiquitous in low-temperature alcohol oxidation. These findings will substantially alter current alcohol oxidation mechanisms. Moreover, the methods described will be useful for the more general phenomenon of interacting radical and zwitterionic states. © 2013 American Chemical Society.

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TYPE Conference YEAR 2013
ScopusOSTI

A coupled level set-moment of fluid method for incompressible two-phase flows

Journal of Scientific Computing

Jemison, Matthew; Loch, Eva; Sussman, Mark; Shashkov, Mikhail; Arienti, Marco; Ohta, Mitsuhiro; Wang, Yaohong

A coupled level set and moment of fluid method (CLSMOF) is described for computing solutions to incompressible two-phase flows. The local piecewise linear interface reconstruction (the CLSMOF reconstruction) uses information from the level set function, volume of fluid function, and reference centroid, in order to produce a slope and an intercept for the local reconstruction. The level set function is coupled to the volume-of-fluid function and reference centroid by being maintained as the signed distance to the CLSMOF piecewise linear reconstructed interface. The nonlinear terms in the momentum equations are solved using the sharp interface approach recently developed by Raessi and Pitsch (Annual Research Brief, 2009). We have modified the algorithm of Raessi and Pitsch from a staggered grid method to a collocated grid method and we combine their treatment for the nonlinear terms with the variable density, collocated, pressure projection algorithm developed by Kwatra et al. (J. Comput. Phys. 228:4146-4161, 2009). A collocated grid method makes it convenient for using block structured adaptive mesh refinement (AMR) grids. Many 2D and 3D numerical simulations of bubbles, jets, drops, and waves on a block structured adaptive grid are presented in order to demonstrate the capabilities of our new method. © Springer Science+Business Media, LLC 2012.

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TYPE Journal Article YEAR 2013
ScopusOSTI

Inexact subgraph isomorphism in MapReduce

Journal of Parallel and Distributed Computing

Plantenga, Todd

Inexact subgraph matching based on type-isomorphism was introduced by Berry et al. [J. Berry, B. Hendrickson, S. Kahan, P. Konecny, Software and algorithms for graph queries on multithreaded architectures, in: Proc. IEEE International Parallel and Distributed Computing Symposium, IEEE, 2007, pp. 1-14] as a generalization of the exact subgraph matching problem. Enumerating small subgraph patterns in very large graphs is a core problem in the analysis of social networks, bioinformatics data sets, and other applications. This paper describes a MapReduce algorithm for subgraph type-isomorphism matching. The MapReduce computing framework is designed for distributed computing on massive data sets, and the new algorithm leverages MapReduce techniques to enable processing of graphs with billions of vertices. The paper also introduces a new class of walk-level constraints for narrowing the set of matches. Constraints meeting criteria defined in the paper are useful for specifying more precise patterns and for improving algorithm performance. Results are provided on a variety of graphs, with size ranging up to billions of vertices and edges, including graphs that follow a power law degree distribution. © 2012 Elsevier Inc. All rights reserved.

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TYPE Journal Article YEAR 2013
OSTIScopus
Results 59501–59600 of 99,299
Results 59501–59600 of 99,299