The total cross sections of the reactions DDp, DDn, TD at 10 kev to 10 Mev are estimated from a review of the experimental data up to January 1951. Maxwell averages for DDp and TD computed from these estimates are given, together with some fitted analytic expressions provided for machine use. A collection of the identifiable earlier estimates is also included for reference and for comparison with the new figures. For relative order of magnitude purposes, cross sections and the derived Maxwell averages are given down to 50 ev using the theoretical Gamow slopes for the extrapolation. Gamow plots for the derived cross sections above l0 kev arc also given. Much of the primary experimental data exists in the form of thick target yields and we find the most uncertain factor in converting these thick targets yields into cross sections is the magnitude of the D/sub 2/O stopping cross section. The particular D/sub 2/O stopping cross section relation used in this derivation together with some of the earlier stopping cross sections are given. Thick target yields are included for both DD and TD on D/sub 2/ targets, at 0.01 to 1 Mev, experimental values being supplemented by calculated values.

One of the problems connected with the sweptback wing is the difficulty of controlling the location of the center of pressure and hence the pitching moment. A method is presented for designing a wing to be self-trimming at a given set of flight conditions. Concurrently, the spanwise distribution of load on the wing is made to be approximately elliptical, in an effort to maintain low wing drag.

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From Introduction: "This report shows correlation between actual transient data obtained from the engine and solutions to a simulated system set up on an analog computer. Data are presented for response of engine speed to changes in set speed when the power plant was being controlled by a relay-type electronic governor that acted to maintain set speed by varying propeller pitch. Correlation obtained for sea-level conditions between actual time data and analog solutions is discussed."

From Wing Thickness: "A brief review of the effect of wing thickness and thickness distribution on the high-speed performance and stability characteristics of a representative configuration is presented."

The performance of a jet power plant consisting of a compressor and a turbine is determined by the characteristic curves of these component parts and is controllable by the characteristics of the compressor and the turbine in relation to each other. The normal. output, overload, and throttled load of the Jet power plant are obtained on the basis of assumed straight-line characteristics.

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Report discussing progress made in metallurgy by the Ames Laboratory during the the term from October 1, 1950 to March 31, 1951.

This report provides fundamental equations and maps to calculate neutron behavior in a spherical cavity.

From Introduction: "Altitude-chamber and wind-tunnel investigations of the performance of turbojet engines such as those reported in references 1 to 4 have shown that the conventional correction factors fail to generalize the engine performance variables at high altitudes. An investigation was therefore made at the NACA Lewis laboratory to determine the altitude performance of the J33-A-23 turbojet engine and to demonstrate the magnitude of departure of actual altitude performance from that predicted from sea-level performance."

Technical report covering the Homogeneous Reactor Experiment (HRE) reactor physics and engineering, out-of-pile corrosion, in-pile studies, recombination of hydrogen and oxygen, HRE chemical studies, experimental programs for the HRE, and long-range studies. [From Summary]

We investigate the possibilities of using another reagent than glue as a filtration aid in South African ore treatment.

Report presenting a partly linearized solution of plastic deformation of a rotating disk based on the deformation theory of plasticity and considering finite strains. The method can be used to investigate the general plastic behavior of a rotating disk.

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"Investigations have been made in flight and in wind tunnels to determine which components of turbojet installations are most critical in icing conditions, and to evaluate several methods of icing protection. From these studies, the requirements necessary for adequate icing protection and the consequent penalties on engine performance can be estimated. Because investigations have indicated that the compressor-inlet screen constitutes the greatest icing hazard and is difficult to protect, complete removal or retraction of the screen upon encountering an icing condition is recommended" (p. 1).

Studies were continued on processes for the separation and purification of Ac/sup 227/ from neutron-irradiated Ra and for the deposition of Ac on various metal surfaces. (For preceding period see MLM-519.) (C.W.H.)

The work presented in this volume concludes the research on methods for the recovery of purified radium from K-65 residues. The completion of a final report and an engineering study of the proposed process are underway. The preliminary treatment of the K-65 residues with 15% sodium hydroxide was checked and found to give 84% removal of lead and 40% removal of silica. The combined sodium hydroxide, sodium carbonate treatment for removing additional amounts of lead and achieving a preliminary conversion of the radium-barium silfates to carbonates has been studied at 170 deg C under pressure as well as at 100 deg C as previously used. A marked improvemont was found with the use of higher temperatures. Alternate methods were studied for removing the residual lead content in place of precipitation with hydrogen sulfide. Precipitation of insoluble hydroxides was found to remove about 90% of the lead present. The over-all recovery of radium in the residues treatment has been checked and found to be better than 98%. The work on the separation of radium from barium by fractional precipitation of the chromates has shown that in actual practices the results are in good agreement with the results calculated from the observed …