Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

Fast parallel algorithms for short-range molecular dynamics

介绍了Kirk—Othmer Encyclopedia of Chemical Technology（化工技术百科全书）（第五版）电子图书网络版数据库，并对该数据库使用方法和检索途径作出了说明，且结合实例简单地介绍了该数据库的检索方法。

Kirk-Othmer Encyclopedia of Chemical Technology数据库介绍及实例

An immersed boundary method with direct forcing for the simulation of particulate flows

The Maxwell-Stefan approach to mass transfer

Discrete particle simulation of particulate systems: A review of major applications and findings

Studies in char gasification-II. The Davidson-Harrison two phase model of fluidization

Coarse-grained (a.k.a. filtered) models for gas-particle flows strive to resolve coarse flow structures, while capturing the consequences of smaller scale processes through filter-size dependent closures. Through a combination of Euler-Euler and Euler-Lagrange simulations, we find that at small length scales the principal competition is between gravitational and particle phase stress, while at larger length scales it is between gravitational and particle inertia.

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Coarse-Grained Models for Momentum, Energy and Species Transport in Gas-Particle Flows

Three-way catalysts used for treatment of automobile exhaust gas or gas emissions from stationary combustion sources, which typically have consisted of platinum and rhodium and sometimes palladium and rhodium dispersed on an γ-alumina support, can have the activities of the active metals in the catalysts appreciably enhanced by using an oxygen-ion conducting material such as yttria-stabilized-zirconia (YSZ) as the support material. Support material surface area is 20-300 m2 /gm, and useful concentrations of yttria on zirconia support are 1.0-50 wt. %. Useful concentrations of platinum or palladium on the support material is 0.01-2 wt. %, and the weight ratio of rhodium/platinum or rhodium/palladium is 0.01-0.1. YSZ-supported catalysts can achieve a substantially higher level of pollutants (CO, NOX, H2 and hydrocarbons) removal, without requiring increased loading of expensive precious active metals on the support material.

Precious metal catalysts with oxygen-ion conducting support

The response characteristics of dense assemblies of cohesive granular materials to unsteady simple shear in the quasi-static regime are investigated through discrete element method (DEM) simulations of monodisperse spherical and frictional particles in periodic domains at constant volume. The dynamics of the volume-averaged normal and shear stresses in materials, undergoing stop-and-go shearing and oscillatory shear, are studied in detail. Furthermore, the evolution of microstructure anisotropy has been quantified through a fabric tensor. The stresses and the microstructure anisotropy depend on the strain extent but not on the shear rate. They both undergo a transition following reversal of shear direction, which requires a shear strain of order unity to fully adapt. The results reveal a correlation between the stress evolution and the microstructure anisotropy development.

Sankaran Sundaresan

Papers

Studies in char gasification-II. The Davidson-Harrison two phase model of fluidization

Coarse-Grained Models for Momentum, Energy and Species Transport in Gas-Particle Flows

Precious metal catalysts with oxygen-ion conducting support

Unsteady Shear of Dense Assemblies of Cohesive Granular Materials under Constant Volume Conditions

Time dependent hydrodynamics in multiphase reactors