This monthly progress report covers activities in the following areas: pile control; shielding studies; process tube assembly; pile operating equipment; power recovery; pile piping; and test laboratory. A detailed discussion is given for each topic.

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Simple expression are derived for the time dependence of slowing down of neutrons in a simple media. In Section I, a method suggested by age theory is used, while in section II, a two parameter scattering function is employed. Results are compared with exact calculations.

Report presenting a technique for obtaining a physical picture of the flow behind a wing, combination of wings, or other aircraft components is described. The technique involves photographing from far downstream the action of a large number of tufts of uniform length mounted on a screen. Results regarding the angle of attack variations at zero yaw, effect of sideslip, deflecting tip controls, and yawing oscillation tests are provided.

Report issued by the U.S. Bureau of Mines on the properties of aviation gasoline and fuel produced during October 1951. Analysis of the gasoline and fuels sampled are presented. The report includes tables and graphs.

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Note presenting graphs for rapid evaluation of air-induction systems from considerations of their aerodynamic-performance parameters in combination with power-plant characteristics. The graphs cover the range of supersonic Mach numbers up to 3.0. The illustrative examples indicate that the inlet area required for optimum performance must change with altitude at a fixed Mach number as well as with Mach number at a fixed altitude.

This quarterly progress discusses the ongoing work at the Oak Ridge National Laboratory for the quarter ending in March 10, 1952. Topics discussed include reactor theory and design, shielding research, materials research, and includes appendixes with supplemental information.

This document describes aspects of heat transfer for the Hanford production reactors. Boiling, flow rate, cooling water failures, thermocouples, and shielding are considered.

Abstract: "A quantitative method for the determination of individual rare earths in thorium down to a level of 0.05 ppm, is described. The procedure consists of a chromatographic cellulose-columns separation followed by a solution-type spectrographic determination. Values are given for the recovery of a number of rare earths using this combined procedure."

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"A modified triangular wing of aspect ratio 2.53 having an airfoil section 3.7 percent thick at the root and 5.98 percent thick at the tip was designed in an attempt to improve the lift and drag characteristics of triangular wings. Free-flight drag and stability tests were made using rocket-propelled models equipped with the modified wing. The Mach number range of the test was from 0.70 to 1.37" (p. 1).

From to the files: To date, all the mineralization seen in the Monument Valley area in the Shinarump formation has been in scour channels. The mineralized rock occurs at or near the bottom of the channel. On Hoskinnini Mesa, all the channels examined to date contain some mineralized material. Channels observed may in some cases contain copper without apparent uranium mineralization; others definitely exhibit copper-uranium mineralization.

This report presents "Results of a critical literature review on pressure drop due to isothermal turbulent flow in noncircular geometries" (introduction).

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From Abstract: "A study of the critical factors in the colorimetric determination of total iron in silicate and phosphate rocks, and in other nonmetallic materials is presented. It was desired to ascertain the wavelength of maximum absorbancy, the optimum concentration range for iron, the effect of different substances on the ferrous-o-phenanthroline system, and reproducibility of results."

Report presenting an investigation at Mach number 1.6 and a range of Reynolds number of the skin-friction drag and boundary-layer transition of a body of revolution. The body had a parabolic-arc profile, a blunt base, and a fineness ratio of 12.2 (NACA RM-10). Results regarding the effect of surface condition, drag breakdown, and results of boundary-layer surveys are provided.

"A derivation of the form of the incompressible turbulent skin-friction law for an insulated flat plate is made in such a way that it may be extended to compressible flows. The ratio of compressible to incompressible skin friction is obtained, and the results are shown to be in agreement with existing experimental results" (p. 1).

Report presenting a study and experimental investigation on the pressure rise across shock waves required to cause separation of the boundary layer on a flat plate. The interaction of shock wave and boundary layer was investigated experimentally when the boundary layer was caused to separate from the surface of a tube. Results regarding testing and correlation with other results are provided.

Abstract: The yields of U²³⁷ and a fission product were measured as a function of maximum betatron energy, The ratio of the number of fissions divided by the number of U²³⁷ atoms increases with increasing maximum betatron energy. This is consistent with the picture that the higher-energy gammas leave the U²³⁷ atoms with enough excitation energy (above photofission and photoneutron thresholds) to also decay by fission or neutron emission. This secondary process increases the number of fissions and decreases the U²³⁷ yield, this increasing the above ratio.

Note presenting a study that is part of a program of experimentation with external noise reduction on light airplanes. Two light airplanes modified by reduction gears, four-bladed propellers, and engine exhaust silencers were flown in comparison with two standard airplanes at a number of sites that may be useful as landing strips. Some conclusions regarding the number and types of complaints received are provided.

From Introduction: "The Ames Aeronautical Laboratory has in progress an experimental investigation of the aerodynamic characteristics of wings of interest in the design of high-speed fighter aircraft. This program included an investigation in the Ames 6-by 6-foot supersonic wind tunnel at both subsonic and supersonic Mach numbers of a wing-body combination having a 3-percent-thick, unswept, tapered wing with circular-arc sections and an aspect ratio of 3.1 (reference 1).

Report of equations for calculating decay of U235. The introduction states" Calculations have been made on the U235 fission product decay schemes. The results for a typical example, that of a reactor operating at 1000 kilowatts for 180 days, have been tabulated and graphed. General formulae have been used so that the results can be applied for any power level and any time of irradiation" (p. 2).

During the preliminary operaton of a volatilization apparatus it became apparent that a large stopcock in the high vacuum side of the oil diffusion pump was quite unsatisfactory. Since it was necessary to mount the stopcock in a relatively inaccessible location, the difficulty of turning the plug and the consequent necessity of regreasing the valve approximately every week were real problems. Also, it became apparent that an increased pumping speed through the valve would be required. Since a larger stopcock was out of the question, a type of valve reported by Stern was modified in design and was bulit into the apparatus.