A method of constructing fins of nearly optimum proportions has been developed by the NACA to the point where a cylinder has been manufactured and tested. Data were obtained on cylinder temperature for a wide range of inlet-manifold pressures, engine speeds, and cooling-pressure differences. The results indicate that an improvement of 40 percent in the outside-wall heat-transfer coefficient could be realized on the present NACA cylinder by providing a thermal bond equivalent to that of an integral fin-cylinder wall combination between the preformed fins and the cast cylinder wall" (p. 107).

"Theoretical investigations have shown that, because air is compressible, the pressure-drop requirements for cooling an air-cooled engine will be much greater at high altitudes and high speeds than at sea level and low speeds. Tests were conducted by the NACA to obtain some experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. The results reported in the present paper are regarded as preliminary to tests on single-cylinder and multicylinder engines. Tests were conducted over a wide range of air flows and density altitudes" (p. 1).

"Theoretical investigations have shown that, because air is compressible, the pressure-drop requirements for cooling an air-cooled engine will be much greater at high altitudes and high speeds than at sea level and low speeds. Tests were conducted by the NACA to obtain some experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. The results reported in the present paper are regarded as preliminary to tests on single-cylinder and multi-cylinder engines. Tests were conducted over a wide range of air flows and density altitudes" (p. 185).

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Technical report describing development of the Clinton alpha amplifier. The circuit for the Clinton alpha amplifier which is used with an Offner scaler is shown attached to the report. It consists of a pre-amplifier mounted in a cylindrical alpha chamber, followed by a three state amplifier and a pulse height selector in a separate cabinet. Pulses are fed from the pulse height selector in the amplifier to the input tube of the Offner scaler. Through the third stage of the amplifier, this circuit is exactly the same as the California circuit now used by the chemical section for alpha counting. A type 961 Offner scaler was used for these tests. None of the latest Offner scalers type961A, were available to us when the tests were made. Method of testing is given, results are tabulated, computations are made, and eight graphs are given. it appears that the Clinton amplifiers used with a Offner scaler will give substantially the same performance as that given by the California circuit.

Various experimenters have shown (H.H. Gersman U.S. Patent 2,335,590, Nov. 30, 1943; Aluminum Co. of America, various technical papers; also CT-482) that when a billet is extruded by proper technique into a rod (or tube by a floating mandril) that flow of material is streamline and and the extruded article is essentially a space replica of the billet, with linearly distorted coordinates. Advantage is taken of this fact in the manufacture of alclad tubing in which a billet containing an inner core of one alloy with the outer part of another alloy cast around it is extruded together into an integral tube, e.g., to combine high corrosion resistance with high strength. The following experiments were carried out because of the desirability of obtaining a control rod which can be water cooled (or immersed in P9) and which contains boron. For some pile structures it may be desirable to have the major portion of the energy released by the neutron absorption of the control rod be spend in the rod itself by the nuclear reactions [formula] rather than in the surrounding media as is the case when absorption of neutrons is by cadmium according to the reaction [formula]. In the later …