From American Chemical Society 145th National Meeting, New York, Sept. 1963. The pyrolysis of diborane was examined using a chemical shock tube as a reactor. Additional evidence for the existence of hexaborane-12 and heptaborane- 11 and -13 was obtained. The presence of a large net normal isotope effect in the formation of tetraborane and hexaborane and a net inverse isotope effect in the formation of pentaborane-9 are observed. A mechanism, consisting of a series of competitive reactions and eqailibria, in which tetraboraue is the precursor of pentaborane-11 and hexaborane but not of pentaborane-9 is shown to be compatible with the observed isotope effect. Data obtained by examining the pyrolysis of various mixtures of boron hydrides are also consistent with the mechanism. (auth)

The probability of accidents to tractor semitrailers is developed through analysis of accident frequency data in relation to season; geographical factors; road type, traffic and populatlon density; and type of carrier business. Maximum likelihood rates are developed for the potential carriers of radioactivity. Impact characteristics of accidents are studied through the analysis of mass, speed, and energy relations and the effect of these on vehicle and cargo damages is explored. (auth)

Nineteen papers presented at the Conference on the Transport of Radionuclides in Fresh Water Systems are given. Separate abstracts were prepared for 18 papers; one was previously abstracted for NSA. (M.C.G.)