Properties of exact hard-disk free volumes are determined by a combination of analytical and numerical technIques. Both the high-density fluid phase and the lower-density fluid phase are treated. These one particle free volumes are used to verify known thermodynamic information for hard disks and to calculate the shear ~odulus for the hard-disk solid phase. The free volumes are also compared to approximate free volume eslimates made from the known hard-disk entropy. The statistical distributions of free volume and free surface (perimeter of the free volume) are studied. The percolation transition, at which the free volume changes from extensive to intensive, is found to occur at about one-third pf the freezing density.

The geometric properties of polygranular microstructures of the Johnson-Mehl and cellular types have been studied through computer simulation. These prototypic microstructures arise naturally from the classical model of a phase transformation in a one-component solid through growth from a random distribution of nucleation sites. The

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Using techniques drawn from the statistical theory of branching processes, we approximate the critical resolved shear stress for the athermal planar glide of a dislocation, idealized as a flexible line of constant tension, through a random mixture of immobile point obstacles

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We consider a dislocation in glide through a random array of point obstacles. Several important phenomena, including the critical resolved shear stress at zero temperature and the velocity of thermally activated glide at low temperature or at stress near the critical resolved shear stress, are known to be strongly influenced by the properties of the most stable obstacle configuration encountered by the dislocatton during glide. We devise a limiting technique to estimate the mechanical strength, the distribution of forces, and the mean dislocation segment length in this configuration. The estimates are in good agreement with results

The Microprocessor Standards Committee of the IEEE Computer Society sponsors two groups drafting proposed standard for floating-point arithmetic. The first, Task P754, reported Draft 10.0 of a Proposed Standard for Binary Floating-point Arithmetic out of committee in December. 1982. That document is now a de facto standard and is progressing slowly through the approval process within the IEEE Computer Society.

In this paper we report the behavior of the plastic deformation of an idealized crystal made by stacking parallel slip planes. Each slip plane is assumed to contain active sources of dislocations leading to a constant density of non-interacting dislocations in the plane which glide through randomly distributed localized point obstacles, representing small precipitates. The dislocation is assumed to have a constant line tension and the dislocation-obstacle interaction is taken to have a simple step form. Using results of computer simulation of thermally activated glide through random arrays of point obstacles we modeled deformation as a function of temperature and applied stress, determining the strain rate and the morphological characteristics of slip.