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

Overview of membrane science and technology membrane transport theory membrane and modules concentration polarization reverse osmosis ultrafiltration microfiltration gas separation pervaporation ion exchange membrane processes - electrodialysis carrier facilitated transport medical applications of membranes other membranes processed.

Membrane Technology and Applications

From the Publisher: 
The accessible presentation of this book gives both a general view of the entire computer vision enterprise and also offers sufficient detail to be able to build useful applications. Users learn techniques that have proven to be useful by first-hand experience and a wide range of mathematical methods. A CD-ROM with every copy of the text contains source code for programming practice, color images, and illustrative movies. Comprehensive and up-to-date, this book includes essential topics that either reflect practical significance or are of theoretical importance. Topics are discussed in substantial and increasing depth. Application surveys describe numerous important application areas such as image based rendering and digital libraries. Many important algorithms broken down and illustrated in pseudo code. Appropriate for use by engineers as a comprehensive reference to the computer vision enterprise.

Computer vision : a modern approach = 计算机视觉 : 一种现代的方法

Arsenic removal from water/wastewater using adsorbents—A critical review

Beyond Oil and Gas: The Methanol Economy

Statistical and continuum models of fluid-solid reactions in porous media

A study by in situ techniques of the thermal evolution of the structure of a Mg–Al–CO3 layered double hydroxide

Electrochemical Reaction Dynamics - A Review

A diffusion process from steam reforming of a hydrocarbon to produce H 2 , Co and CO 2 , that includes: providing a generally tubular, porous, ceramic membrane, and providing a heated reaction zone in a container into which the membrane is received; the membrane carrying a catalytically active metallic substance; passing a hydrocarbon and steam containing first fluid stream into the zone and into contact with one side of the membrane, to produce CO, CO 2 and H 2 ; and passing a second fluid stream adjacent the opposite side of the membrane in such manner as to promote hydrogen diffusion through the membrane from said one side to said opposite side thereof; and removing hydrogen from the opposite side of the membrane. Such a process may be combined with operation of a heat engine or gas turbine, producing heat transferred to the referenced reaction zone.

Catalytic ceramic membrane steam-hydrocarbon reformer

The adsorption of As and Se from dilute aqueous solutions, representing model power-plant effluent streams, by calcined and uncalcined layered double hydroxide (LDH) adsorbents has been investigated. The results indicate that As(V) has a greater adsorption capacity than Se(IV) for both calcined and uncalcined LDHs. An mth-order kinetic rate equation describes the adsorption kinetics of As and Se on these adsorbents. The adsorption isotherms obey the Freundlich model. The adsorption capacities of As(V) and Se(IV) on the calcined LDH are higher than those on the uncalcined LDH. The starting solution pH does not significantly influence adsorption of As and Se on calcined LDH, as long as it is higher than 4; As and Se adsorption on uncalcined LDH is, however, more sensitive to variations in the initial pH. Studies of the effect of the metal oxidation state on adsorption reveal that As(III) is more difficult to remove than As(V) by both the calcined and uncalcined LDHs. However, the adsorption of Se(IV) and Se(VI) is relatively similar on both calcined and uncalcined LDHs. Competing ions have a greater effect on Se(IV) uptake than on As(V) uptake. Desorption of As(V) and Se(IV) from the LDH depends on the type of ion species and their concentration in the desorbing solutions.

Theodore T. Tsotsis

Papers

Statistical and continuum models of fluid-solid reactions in porous media

A study by in situ techniques of the thermal evolution of the structure of a Mg–Al–CO3 layered double hydroxide

Electrochemical Reaction Dynamics - A Review

Catalytic ceramic membrane steam-hydrocarbon reformer

Removal of Trace Levels of Arsenic and Selenium from Aqueous Solutions by Calcined and Uncalcined Layered Double Hydroxides (LDH)