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

Statistics for Spatial Data.

THE author of this book ranks as the foremost American worker on insect morphology. His contributions on the subject are notable for their clarity and originality of thought, and the appearance of a volume, embodying his ideas in comprehensive form, is sure of a hearty welcome. In its preparation, Mr. Snodgrass has incorporated the results of much first-hand study with those of many recent investigators in the same field. He has produced an outstanding book wherein knowledge of facts is combined with that of function and, at the same time, theoretical conceptions of the origins and relationships of organs and parts are not overlooked. Principles of Insect Morphology
 By R. E. Snodgrass. (McGraw-Hill Publications in the Zoological Sciences.) Pp. ix + 667. (New York and London: McGraw-Hill Book Co., Inc., 1935.) 36s. net.

Principles of Insect Morphology

We have induced large elastic strains in ropes of single-wall carbon nanotubes, using an atomic force microscope in lateral force mode. Freely suspended ropes were observed to deform as elastic strings with tension proportional to elongation. Ropes were elastically deformed over >10 cycles without showing signs of plastic deformation. The maximum strain observed, 5.8±0.9%, gives a lower bound of 45±7 GPa for the tensile strength (specifically, yield stress) of single-wall nanotube ropes.

Elastic strain of freely suspended single-wall carbon nanotube ropes

Morphological and microstructural changes of the oral apparatus in two Anuran tadpoles, in regard to pH

This paper presents a comparative assessment of surrogate models in probabilistic analysis of finite plain journal bearing. Traditional Monte Carlo simulation (MCS) is employed dealing with a large number of data for validating the constructed surrogate model dealing with a limited number of data. In the case of a complex engineering system like journal bearing with finite length wherein no analytical solution exists and the system needs to be solved based on expensive numerical techniques such as finite difference and finite element method due to unavailability of a large number of experimental data. Hence, surrogate models show their computational efficiency complying with the accuracy of the models. Thus, the present study aims to investigate the applicability of five surrogate models such as moving least square, support vector machine, radial basis function, polynomial neural network and multivariate adaptive regression splines in terms of their efficiency and accuracy. A probabilistic analysis approach combining the finite difference method, surrogate models and MCS is presented in this work. The validation and parametric results corresponding to the comparison of the constructed surrogate models are presented. Substantial intuitive new results are conferred in the probabilistic surrogate schemes.

Comparative evaluation on probabilistic performance of journal bearing: a surrogate-based approach

This paper presents a finite element method to compare the effects of delamination on free vibration of graphite-epoxy bending stiff and torsion stiff composite pretwisted shallow conical shells. The generalized dynamic equilibrium equation is derived from Lagrange’s equation of motion neglecting the Coriolis effect for moderate rotational speeds. An eight noded isoparametric plate bending element is employed incorporating rotary inertia and effects of transverse shear deformation based on Mindlin’s theory. The multipoint constraint algorithm is utilized to ensure the compatibility of deformation and equilibrium of resultant forces and moments at the delamination crack front. The standard eigen value problem is solved by applying the QR iteration algorithm. Mode shapes for typical configurations are also depicted. Numerical results obtained are the first known non-dimensional frequencies which could serve as reference solutions for the future investigators.

A comparative study on free vibration analysis of delaminated torsion stiff and bending stiff composite shells

The larval mouth part sensilla trichodea in Antheraea assamensis revealed differential distribution pattern of pores and lumen in different parts of the same sensilla. Pores were sparse in the tip as compared to the middle portion. Similarly lumen was well developed near the base but it was not observed in the tip. Sensilla cheatica, on the other hand were represented by porous as well as aporous types. Two types of sensilla basiconica (uniporous and multiporous), an aporous sensilla digitiform and placoid sensilla were detected. Most of the sensilla were found to be innervated by the dendrites of one or more sensory neurons. The fine structural details and distribution of dendrites, thickness of walls of sensilla, porosity of sensilla, presence ,absence and the nature of lumen of different sensilla have been studied, and their significance in sensory physiology are discussed in the light of available literature.

http://journals.dbuniversity.ac.in/ojs/index.php/JFAS/article/download/205/214

Fine structural studies on major larval mouth part sensilla of antheraea assamensis, an endemic silk moth species of north east india in regard to sensory physiology

This paper presents a finite element method to investigate the effects of delamination on free vibration characteristics of graphite-epoxy pretwisted shallow angle-ply composite conical shells The generalized dynamic equilibrium equation is derived from Lagrange's equation of motion neglecting Coriolis effect for moderate rotational speeds The theoretical formulation is exercised by using an eight noded isoparametric plate bending element based on Mindlin's theory Multi-point constraint algorithm is utilized to ensure the compatibility of deformation and equilibrium of resultant forces and moments at the delamination crack front The standard eigen value problem is solved by applying the QR iteration algorithm Finite element codes are developed to obtain numerical results concerning the effect of twist angle, location of delamination and rotational speed on natural frequencies of delaminated angle-ply composite conical shells The mode shapes are also depicted for a typical laminate configuration Parametric studies of symmetric and anti-symmetric angle-ply laminates provide the non-dimensional natural frequencies which are the first known results for the type of analyses carried out here

Sudip Dey

Papers

Morphological and microstructural changes of the oral apparatus in two Anuran tadpoles, in regard to pH

Comparative evaluation on probabilistic performance of journal bearing: a surrogate-based approach

A comparative study on free vibration analysis of delaminated torsion stiff and bending stiff composite shells

Fine structural studies on major larval mouth part sensilla of antheraea assamensis, an endemic silk moth species of north east india in regard to sensory physiology

Free Vibration of Delaminated Composite Shallow Conical Shells