Light microscopy, bare-film radiography, secondary ion mass spectroscopy, electron microprobe and physical testing were used to examine beryllium specimens exhibiting a stratified, pitted, pattern after chemical milling. The objective was to find the cause of this pattern. Specimens were found to have voids in excess of density specification allowances. These voids are attributed, at least in part, to the sublimation of beryllium fluoride during the vacuum hot pressing operation. The origin of the pattern is attributed to these voids and etching out of fines and associated impurities. Hot isostatic pressing with a subsequent heat treatment close residual porosity and dispersed impurities enough to correct the problem.

This paper surveys recent advances in the application of implicit integration schemes to particle simulation of plasmas. The use of implicit integration schemes is motivated by the goal of efficiently studying low-frequency plasma phenomena using a large timestep, while retaining accuracy and kinetics. Implicit schemes achieve numerical stability and provide selective damping of unwanted high-frequency waves. This paper reviews the implicit moment and direct implicit methods. Lastly, the merging of implicit methods with orbit averaging can result in additional computational savings.

One scheme is considered, acceleration of a ring between coaxial electrodes by a B/sub theta/ field as in a coaxial rail-gun. If the electrodes are conical, a ring accelerated towards the apex of the cone undergoes self-similar compression (focussing) during acceleration. Because the allowable acceleration force F/sub a/ = kappa U/sub m//R (kappa < 1) increases as R/sup -2/, the accelerating distance for conical electrodes is considerably shortened over that required for coaxial electrodes. In either case however, since the accelerating flux can expand as the ring moves, most of the accelerating field energy can be converted into kinetic energy of the ring leading to high efficiency.

Much of the tritium found in soil and leaf litter near a chemical separations facility is incorporated into soil organic matter in a stable non-exchangeable form. Formation of this ''bound'' tritium seems to result from the uptake of molecular tritium (HT) by living pine needles. Soil and litter microbes convert HT to HTO more rapidly, but no measurable organic tritium is formed. This report discusses this study.