"In this report are presented three figures which show how the relative activities (expressed as percentages of total activity) of the individual fission elements (produced by neutron bombardment of uranyl nitrate) vary with cooling time."

The following report provides data taken from investigations on radiation and the different biologic effects on it.

The following represents a summary of calculations on the multiplication constant of homogeneous mixtures of uranium and different moderators. These calculations were made possible by Fermi's determination of the age of neutrons and by the extrapolation to higher scattering cross-sections of the resonance absorption of uranium as measured by C. Creutz. According to Fermi, the former quantity is 120 sq. cm. The latter is given in the two attached graphs. The first (Fig.1) of these goes as high as a scattering cross-section of 70 x 10-24 cm.2 per uranium atom, and its highest point is taken from a measurement of Cruetz's in which a mixture of U3O8 and graphite was used.

Technical report that information has bee obtained on the effect of beta and gamma radiation on the electrical resistance of insulating materials The results are summarized. The recovery to original resistance values has been measured. In general, the initial rate is rapid for the first few hours; the rate then decreases sharply. Certain samples show evidence of complete recovery. Effects on mechanical properties of several plastics has also been studied. Data on gas evolution from several organic materials including those suggested by the physiological shield have been extended to include both beta and deuteron bombardments. Samples of "Press-wood" are being evaluated. The effect of current on the H2O2 production in water containing I- has been studied at several I- concentrations. Water contain-dissolved CO2 shows the presence of oxidant (presumably H2O2). H2O2 has been produced by recoil protons from the scattering of fast neutrons in de-oxygenated water. Radioactive solutions do not greatly affect the applicability the glass electrode providing the electrode is thoroughly washed with distilled water before immersion in the standard buffer solution.

The importance of fast neutron fission (i.e., fission caused by neutrons before being slowed down) was recognized by Szilard, and calculations similar to the present one have already been carried out by him, Feld, Ashkin, Wheeler, Wigner and others. The purpose of the present paper is to give a general formula for the contribution of fast fission to the multiplication constant, which will include all the cases already considered and will be applicable to more complicated geometries than those considered by the previous writers.

Lecture notes from a training program. "It is the function of the section on radiation chemistry to determine the effects of all radiations and high energy particles produced under the various operating conditions on all the materials which will be exposed to them."

Report issued by the U.S. Bureau of Mines discussing studies over the research and technology of coal during 1942. As stated in the introduction, "the annual reports of the research and technologic investigations conducted by the Bureau of Mines on the occurrence, properties, mining, preparation, and uses of coal, of which the present report is the seventh, are intended to be brief summaries of progress" (p. 4). This report includes tables, illustrations, and photographs.

Report presenting an investigation of the force characteristics of single hydrofoils in order to help with preliminary hydrofoil design.

Summary: The effective change in the velocity of flow past a wing section, caused by the presence of wind-tunnel walls, is known for potential flow. This theory is extended by investigation of the two-dimensional compressible flow past a thin Rankine Oval. It is shown that for a symmetrical section at zero angle of attack the velocity increment due to the tunnel walls in the incompressible case must be multiplied by the factor 1/1-M^2 to take account of compressibility effects. The Mach number, M, corresponds to conditions in the wind-tunnel test section with the model removed (p. 1.).

Report discusses the results of two tests: "1) aerodynamic tests to determine the effect of the slipstream and thrust from the powered propellers on the lift and trimming-moment characteristics, and 2) hydrodynamic tests to determine the effect of the powered propellers on the range of stable locations of the center of gravity (from Introduction)." Large differences in the stable range between half-thrust and full-thrust conditions were observed. Three effects of power were also involved in the location of the stable range of the center of gravity.

"An analysis was made to show the relative effectiveness of streamline external fuel tanks, a fuel tank in the form of a wing mounted in a biplane position, and auxiliary wing panels attached at the wing tips to increase the span as temporary means for increasing the range of a fighter-type airplane. Figures and charts for the various devices considered show the results of calculations of range, duration of flight, and take-off distance for both land-base and carrier operation. The results indicated that the wing-tip extensions were the most promising of the devices considered" (p. 1).

Report presenting formulas for propellers for the rate of change of side-force coefficient with angle of yaw and for the rate of change of pitching-moment coefficient with angle of yaw. Charts of side-force derivatives are given for two propellers of different plan forms.

Report presenting a series of tests made in the 15-foot free-spinning tunnel to study the spin characteristics of a model of a hypothetical canard airplane, which was designed to be about the same size and have the same general aerodynamic characteristics as a Boeing B-247 airplane. The model spun normally and had excellent recovery characteristics.

Report presenting measurements made of the pressures of the tail surfaces of the Republic Aviation Corporation P-47B airplane in the full-scale tunnel. Pressures were measured over the horizontal and vertical tail surfaces for several angles of attack and angles of yaw with numerous control-surface deflections to provide a check on the design loads. Results regarding the normal-force coefficients and predictions of forces on horizontal tail surfaces are provided.

From Summary: "The heat transfer in the laminar boundary layer of a heated plate in flow at high speed can be obtained by integration of the conventional differential equations of the boundary layer, so long as the material values can be regarded as constant. This premise is fairly well satisfied at speeds up to about twice the sonic speed and at not excessive temperature rise of the heated plate. The general solution of the equation includes Pohlhausen's specific cases of heat transfer to a plate at low speeds and of the plate thermometer. The solution shows that the heat transfer coefficient at high speed must be computed with the same equation as at low speed, when it is referred to the difference of the wall temperature of the heated plate in respect to its "natural temperature." Since this fact follows from the linear structure of the differential equation describing the temperature field, it is equally applicable to the heat transfer in the turbulent boundary layer."

Report issued by the U.S. Bureau of Mines on the increase of pig-iron during steel production. The machinery, organization, and methods used in the study are presented. This report includes tables, graphs, and photographs.

Report presenting an investigation to develop an instrument for the determination of rain densities in this range in flight. The major requirements for the instrument are ease of operation, minimum weight and bulk, rapid response, and simplicity of installation.

Report presenting performance data on a Trane exhaust gas and air heat exchanger. Heat transfer rates were measured using specified exhaust gas rates and ventilating-air rates. The measured thermal outputs and static pressure drops are compared with predicted magnitudes.

Report presenting a detailed method for determining the jet-boundary corrections for reflection-plane models in rectangular wind tunnels. The principal effects of aerodynamic induction and boundary-induced curvature of the streamlines are considered. An example is included to illustrate the method.

Equations are given for the elastic behavior of initially curved sheets in which the deflections are not small in comparison with the thickness, but at the same time small enough to justify the use of simplified formulas for curvature. These equations are solved for the case of a sheet with circular cylindrical shape simply supported along two edges parallel to the axis of the generating cylinder. Numerical results are given for three values of the curvature and for three ratios of buckle length to buckle width.

"General relationships for the lead susceptibilities of paraffins, cycloparaffins, and olefins are presented. Methods are described by which the lead response may be estimated for these hydrocarbon classes, whether the lead response is indicated by octane number, critical compression ratio, or indicated mean effective pressure as limited by knock" (p. 1).

The distribution of stress in the cover sheets of thin-wall box beams is analyzed, with regard to the effect of shear deformation in the cover sheets, by the method of least work. Explicit results are obtained for a number of representative cases that show the influence of the following factors on the stress patterns. General conclusions are drawn from the results obtained. Among them the most important one appears to be the fact that the shear-lag effect depends primarily on several tow qualities.

"Tests were made of riveted double-angle columns to determine the total rivet strength that is required to make these built-up columns develop the strength predicted by the standard column formulas. Results of the tests led to the conclusion that the required rivet strength may be calculated by the beam method of design" (p. 1).

"A method is developed for calculating the performance of a dual-rotating propeller from the section characteristics of the blade elements. The method is applied to an eight-blade dual-rotating propeller and the computed results are compared with low-speed wind-tunnel tests of the same propeller in both the tractor and pusher positions. The computations are found to agree within the experimental accuracy of the measurements" (p. 1).