On the basis of polonium assays by the customer, an improved equation for the prediction of the polonium content of a bismuth tube has been developed.

Report discussing the effects of Mach number on the aerodynamic characteristics of an Allison powered single-engine pursuit airplane. Information about the lift, drag, pitching-moment characteristics, stability, tail effectiveness, and elevator effectiveness with Mach number is provided.

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A measurement was made of the permanent earth movement in the neighborhood of the tower caused by the nuclear explosion at Trinity. The crater was apparently formed by a compression phenomenon and was noted to be much shallower than craters formed by ordinary high explosives. Scaling up existing information on the radius of craters, the TNT equivalence of the nuclear bomb is given as 10,000 tons to within 50 percent. Observations were made on the damage in the crater region and suggestions are given as to the nature of structure which might be expected to withstand the blast close to the gadget. It is also noted that, despite previous opinion to the contrary, it is apparently possible to reduce greatly the volume of earth blown away by the blast by suitably protecting the ground.

"An investigation was conducted to determine the knock-limited blending characteristics of leaded fuels containing selected aromatic fuel components (benzene, toluene, mixed xylenes, and cumene). Each of the aromatics was blended with an alkylate blending agent and with a virgin base stock. The blending characteristics of the resulting fuels were determined in a full-scale aircraft-engine cylinder" (p. 1).

Report discussing the results of testing to determine the operating life of a 22-inch-diameter pulse-jet engine equipped with a neoprene-coated valve grid. The valve grid was found to extend the operating life and only reduced the performance slightly.

.Technical report describing the transference experiments. The carrying of zirconium and columbium by ferric hydroxide has a very marked dependence on pH. In the experiments it was noticed that the concentration of Zr activity in various solutions changed with time This indicated that the Zr was being adsorbed on the glass. The carrier free trace is adsorbed on glass. This effect must be considered in experiments with Zr tracer in glass apparatus.

Abstract. It has been established that heating samples of graphite during exposure in a pile decreases substantially the observed changes in the elastic modulus and electrical resistance caused by the irradiation. The functional relationship between the percentage changes observed and the temperature of exposure resembles the relationship between the final percentage changes and the temperature of heat treatment after exposure (cf. report CC-1668). Anomalous results reported previously for higher temperatures in CC01669 are now shown to be attributable to a destructive influence on the graphite, probably oxidation of samples exposed in air.