Computational Fluid Dynamics (CFD) is a mathematical tool capable of simulating a wide range of fluid flows. Integrated CFD software has been applied to study the flows in oilfield separators. The influence of inlets, internals, and outlets has been studied with CFD simulations. Of particular value has been the ability of CFD to simulate wave induced sloshing in vessels mounted on floating plat...

We study preconditioners for the iterative solution of the linear systems arising in the implicit time integration of the compressible Navier-Stokes equations. The spatial discretization is carried out using a Discontinuous Galerkin method with fourth order polynomial interpolations on triangular elements. The time integration is based on backward difference formulas resulting in a nonlinear sy...

We study the predictability of emergent phenomena in complex systems. Using nearest-neighbor, one-dimensional cellular automata (CA) as an example, we show how to construct local coarse-grained descriptions of CA in all classes of Wolfram's classification. The resulting coarse-grained CA that we construct are capable of emulating the large-scale behavior of the original systems without accounti...

Debris flows are typically a saturated mixture of poorly sorted particles and interstitial fluid, whose density and flow properties depend strongly on the presence of suspended fine sediment. Recent research suggests that grain size distribution (GSD) influences excess pore pressures (i.e., pressure in excess of predicted hydrostatic pressure), which in turn plays a governing role in debris flo...

We consider additive Schwarz domain decomposition preconditioners for piecewise linear finite element approximations of elliptic PDEs with highly variable coefficients. In contrast to standard analyses, we do not assume that the coefficients can be resolved by a coarse mesh. This situation arises often in practice, for example in the computation of flows in heterogeneous porous media, in both t...

The rate at which CO2 is released from woody debris post-clearcut affects the long term carbon consequences of such disturbances. Changes in microclimate post-clearcut may alter the rate of woody debris decomposition from that in a mature forest. However, very few studies have explored post-disturbance rates of woody debris respiration and the possible influence of an altered microclimate, and ...

This paper proposes a micro-simulation model for urban freight movement, in which the behavior of freight agents and their relationship in supply chains are incorporated. The proposed model is a modification of the traditional four-step approach in that it considers the behavior of each freight agent individually. This paper covers three of the four steps of the traditional approach, including ...

Prior work has shown the utility of syntactic tree fragments as features in judging the grammaticality of text. To date such fragments have been extracted from derivations of Bayesianinduced Tree Substitution Grammars (TSGs). Evaluating on discriminative coarse and fine grammaticality classification tasks, we show that a simple, deterministic, count-based approach to fragment identification per...