The authors would like to acknowledge the Army High Performance Computing Research Center for Agility, Survivability and Informatics, Award No. W911NF-07-2-0027, High Performance Technologies Inc. and Department of the Army (Prime) for partial financial and computational support. In addition, this research has been funded in part by a King Abdullah University of Science and Technology (KAUST) research grant under the KAUST Stanford Academic Excellence Alliance program. Any opinions, findings and conclusions or recommendations expressed in this paper are those of the authors and do not necessarily reflect the views of the KAUST University. Finally, the authors acknowledge the following award for providing computing resources that have contributed to the research results reported within this paper: MRI-R2: Acquisition of a Hybrid CPU/GPU and Visualization Cluster for Multidisciplinary Studies in Transport Physics with Uncertainty Quantification (http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=0960306) This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).