There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

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

THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

Department of Materials Science, University of Patras, 26504 Rio Patras, Greece, Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, 116 35 Athens, Greece, Institut de Biologie Moleculaire et Cellulaire, UPR9021 CNRS, Immunologie et Chimie Therapeutiques, 67084 Strasbourg, France, and Dipartimento di Scienze Farmaceutiche, Universita di Trieste, Piazzale Europa 1, 34127 Trieste, Italy

Chemistry of Carbon Nanotubes

Carbon nanotube–polymer composites: Chemistry, processing, mechanical and electrical properties

Effects of temperature on the deformation of 6H–SiC during nanoscratching

Improving the Interface Bonding of Cnt/Cu Composites Using Cpd Bridges

This paper investigates the effect of statistical surface parameters on the interface temperature estimation during the contact sliding of a pin against a rotating disk. The disk and pin materials were EN26 steel and bulk metallic glass (BMG) Ti40Zr25Ni3Cu12Be20 (at. %), respectively. It was found that the estimated temperature increases with the decrease of summit density and summit radius which depend on the pre-set threshold value of summit. A microstructural analysis of the pin subsurface after the sliding tests revealed that an appropriate estimation of the interface temperature is within a very narrow range of the surface parameter selection. A finite element study demonstrated that the temperature at the real contact areas in the sliding interface, or the flash temperature, varies with the geometries of the asperities in contact. When the flash temperature exceeded the glass transition temperature of the BMG, nano-crystallisation occurs in the subsurface vicinity of such asperities. This was confirmed by the electron microscopy analysis.

Effect of statistical surface parameters on the interface temperature estimation of two solids in contact sliding

A novel auxetic unit cell for 3D metamaterials of designated negative Poisson's ratio

This paper presents a transient thermal analysis of cold strip rolling, integrating both the microscale asperity deformation and macroscale strip deformation. A statistical characterisation was carried out to obtain the contact pressure and thermal contact conductance at the roll-strip interface. To address the effects of rolling speed and temperature rise, Johnson-cook constitutive model of yielding strength was employed to incorporate the strain rate and temperature variation in the analysis. It was found that the developed model can successfully predict both the interface contact stress and temperature rise in the rolling bite.

Liangchi Zhang

Papers

Effects of temperature on the deformation of 6H–SiC during nanoscratching

Improving the Interface Bonding of Cnt/Cu Composites Using Cpd Bridges

Effect of statistical surface parameters on the interface temperature estimation of two solids in contact sliding

A novel auxetic unit cell for 3D metamaterials of designated negative Poisson's ratio

Transient Thermal Analysis of Cold Strip Rolling Considering Rough Surface Contacts