Surface contamination with beryllium becomes a hazard to health only when the potential exists for resuspension in air in enough quantity and for enough time to exceed the prescribed standards for airborne exposures. There are several factors governing the rate and nature of resuspension phenomena. These factors include: the quantity and properties of the particular beryllium compound causing the contamination, the nature of the surface, activities in the vicinity, ventilation in the area which might affect the dilution of resuspended particles, and the presence of other control measures such as respiratory protection and use of wet methods. Generally, it has been found that the problem is minimal and can be easily controlled by exercising good judgement based upon consideration of pertinent factors governing resuspension, and a knowledge of the nature of beryllium toxicity.

In the Plowshare Program many calculations of the effects of underground explosions are made. Usually these are done on high-speed digital computers. The effects are calculated for ranges up to hundreds of meters from the explosion; at these ranges pressures become less than one kilobar. In order to make these calculations, information about the properties of the materials involved is required. Benedick [13] has developed a low-pressure, plane-wave lens using nitroguanidine. It was decided to use a similar lens in the Plowshare Program. A number of lenses were built using Benedick's technique. This report is of a study of simultaneity and pressure uniformity of these lenses, with some attempts at development of a reflection pressure vs particle velocity curve for them.

Over the past 13 years a considerable body of data on explosive cratering has been developed for application to nuclear excavation projects. These data were obtained from some ten cratering programs using chemical explosives (TNT or nitromethane) and seven nuclear cratering detonations. The types of media studied have ranged from marine muck to hard, dry basalt, although most effort has been devoted to craters in NTS desert alluvium and basalt. Considerable effort has also been devoted to the study with chemical explosives of the use of linear explosives and rows of point charges. This paper is intended to be a summary of these data and a statement of the understanding which has been developed from them.

The present study was motivated by an attempt to understand low energy [formula] scattering within the framework of the bootstrap principle and the un-Reggeized version of the strip approximation. This work attempts to generate low energy [formula] scattering in the p(1,1) and p(3,3) states assuming the potential operating in these states is generated by the exchange of low mass meson states in the crossed t-channel and low mass baryon states in the crossed u channel. In particular, the p-meson is kept in channel t; the p mass and the coupling of [formula] and [formula] appear as parameters. The parameters of the nucleon and (3,3) poles are taken as the elements to be determined by self-consistency.

LRL has the responsibility of demonstrating the feasibility of a reactor for use as a power plant for a low-altitude, high-Mach-number missile. This reactor is literally a very high power air heater which must work at temperatures in excess of 2000' F. The reactor is exposed to high loads so one of the primary problems is providing high temperature structure. Considerable effort has been devoted to developing ceramic structural elements. One of the materials considered for this purpose is silicon nitride. In ceramic structural elements operating over large temperature ranges, a major problem is coping with thermal stress. In this respect there is a similarity with the radome problem. The work on silicon nitride at LRL consisted of limited fabrication studies (principally for familiarization), measurement of properties of interest to the application, and funding of fabrication scale-up efforts.