aluminum has been considered as a material for cladding fuel elements to be used in reactors cooled by high-temperature recirculating water. Aluminum is abundant, chap, has a relatively low cross section for thermal neutrons, and is readily fabricated into complex shapes. For these reasons, it appears that the use of aluminum rather than steel, Zircaloy or other candidate materials for fuel element cladding, would result in considerable savings in operating expense. The actual economics will of course depend on specific factors such as core materials and design of the reactor/. Aluminum appears particularly attractive for cladding the cores of aluminum-plutonium alloy proposed for the Plutonium Recycle Test Reactor since, in this case, the physical characteristics of the core and cladding would be practically identical.

Measurements were made of the cooling on the fronts of model cylinders in a conventional cowling for cooling in both the ground and the cruising conditions. The mechanisms of front and rear cooling are essentially different. Cooling on the rear baffled part of the cylinders continually increases with increasing fin width. For the front of the cylinder, an optimum fin width was found to exist beyond which an increase in width reduced the heat transfer. The heat transfer coefficient on the front of the cylinders was larger on the side of the cylinder facing the propeller swirl than on the opposite side. This effect became more pronounced as the fin width was increased. These results are introductory to the study of front cooling and show the general effect of several test parameters.

Memorandum presenting the effects on combustor performance of operation at the high inlet-air pressures, temperatures, and velocities representative of conditions that may be encountered in high-pressure-ratio turbojet engines or at high flight speeds studied in a single tubular combustor. Some of the performance characteristics investigated were combustor-liner temperatures, carbon deposition, smoke formation, and combustion efficiency.

As a result of unreported information, it was suspected by some people that a change in dimension was experienced by 2S Aluminum due to a sudden change in neutron flux impinging on it. This was thought to be of the order of 500 microinches per inch in magnitude. Such an effect, if present, could help explain some of the creep phenomena reported lately (i.e. change in creep rate due to cyclotron bombardment.)

A method similar to that of NACA rep. 1000 is presented for calculating the effectiveness and the reversal speed of lateral-control devices on swept and unswept wings of arbitrary stiffness. Provision is made for using either stiffness curves and root-rotation constants or structural influence coefficients in the analysis. Computing forms and an illustrative example are included to facilitate calculations by means of the method. The effectiveness of conventional aileron configurations and the margin against aileron reversal are shown to be relatively low for swept wings at all speeds and for all wing plan forms at supersonic speeds.

Report presenting an investigation to determine the effects of inlet-annulus blockage on compressor performance and its corresponding effect on the computed performance of a hypothetical engine. The hypothetical engine performance was calculated from the overall compressor performance and assumed component performance characteristics. Results regarding the compressor performance with no inlet blockage, effect of hub blockage on compressor performance and stall characteristics, effect of sector blockage on compressor performance, effect of hub blockage on computed engine performance, and design and control problems are provided.

The gust and draft velocities from records of NACA instruments installed in P-61C airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from September 10, 1947 to September 15, 1947, are presented.

Based on the assumption that the noise contribution of a semiconductor detector is due solely to the bulk properties of the semiconductor, equations are presented which indicate the theoretical limits of noise in detector-amplifier combinations. These equations show that an optimum amplifier time constant and detector bias voltage exist for which condition the minimum noise is independent of the semiconductor resistivity. The optimum performance of a detector-amplifier system is shown to depend only upon detector area, input capacity (less detector capacity), semiconductor minority carrier lifetime, and the transconductance of the amplifier input tube. A new detector structure including a guard-ring electrode as an integral part of the detector structure is described which largely eliminates noise due to surface leakage. Experimental results for detector leakage and energy resolution are presented which agree well with theory.

Report presenting testing of two two-blade propellers in the 8-foot high-speed tunnel for a range of blade angles and Mach numbers. The results show that changes in thrust loading due to compressibility effects were much smaller for the thin-blade propeller than for the thick-blade propeller.

"This report contains the results of tests made in the National Advisory Committee for Aeronautics variable density wind tunnel on three airplane models supplied by the British Aeronautical Research Committee. These models, the BE-2E with R.A.F. 19 wings, the British Fighter with R.A.F. 15 wings, and the Bristol Fighter with R.A.F. 30 wings, were tested over a wide range in Reynolds numbers in order to supply data desired by the Aeronautical Research Committee for scale effect studies. The maximum lifts obtained in these tests are in excellent agreement with the published results of British tests, both model and full scale" (p. 451).

Quarterly progress report discussing activities related to the Vallecitos Boiling Water Reactor (VBWR) and related facilities.

Abstract: "The distribution ratios and equilibrium constants for the extraction of zirconium and hafnium from 4 M perchloric acid with various combinations of fluorinated [beta]-diketones and organic solvents have been determined. The separation factors K'Zr/K'HF, found for this acidity were: Z-thenoyltrifluoroacetone in benzene, 25; Z-thenoyltrifluoroacetone in o-dichlorobenzene, 16; benzoyltrifluoroacetone in benzene, 18; isovaleroyltrifluoroacetone in benzene, 13; isovaleroyltrifluoroacetone in n-hexane, 13."

The phase shifts for proton-proton scattering as calculated from the one-pion exchange contribution (OPEC) alone are of some interest because they describe the scattering correctly in the high angular momentum states, and because in the lower angular momentum states the deviation from the OPEC phases is an indication of the strength of the two-pion and higher exchanges processes. The attached table gives the proton-proton nuclear-bar phase shifts as calculated from OPEC. Phase shifts and mixing parameters are given in degrees, as function of the T, the laboratory kinetic energy of the incoming protons in Mev. Phase shift and mixing parameters are listed in the angular momentum states.

From Introduction: "The investigation is discussed in the present report is an analysis of the turbojet engine as the power plant for bombers capable of supersonic flight speeds. A similar analysis, in which the turbojet engine is considered for the propulsion of supersonic fighter aircraft, is presented in reference 1. Two plans are considered in this report."

From Summary: "This report presents the results of wind-tunnel force tests which were conducted to determine the low-speed stability and control characteristics of a full-scale Northrop XSSM-A-3 missile. Tests were made through a range of angles of attack, sideslip, and control deflection, and at various Reynolds numbers. Characteristics of the complete missile are compared with the characteristics of the missile with the landing skids extended, with the vertical tail removed, and with the fuselage alone. No analysis of the data has been made in order to make the results available as soon as possible."

It is the purpose of this report to present a quantitative picture of the overall waste problems at the presently operating major A.E.C. sites. Presented herewith are data on the volumes and radioactive concentrations of the wastes handled and effluents discharged, available tankage and processes flow sheets from each site.

Report presenting an experimental investigation in a one-sixth sector of an annular turbojet combustor to determine a method of controlling radial exhaust-gas-temperature distribution in a gas-turbine combustion chamber. The adjustment in controlling air was made by ducting the dilution air into the combustion zone in a predetermined manner through hollow radial struts or by modifying the basket-wall open-hole area. Results regarding the temperature distribution, temperature-rise efficiency, total-pressure loss, and altitude operating limits are provided.

From abstract: The principal efforts during the fourth project quarter were the near-completion of the final design and preparation of specifications for plant components. Reactor development work included final preparations for the flexible zero-power test (PMZ-1) program and revised fuel element irradiation test program, continuation of reactor flow test, further work on heat transfer test program, and final design and fabrication of the prototype magnetic jack-type control rod actuators.

Report presenting the results of lift, drag, and pitching-moment measurements on a model of the Douglas D-558-2 airplane at a range of angles of attack and Mach numbers. The model was also tested with two different sets of chordwise fences in order to investigate their effects on force and moment characteristics at high speeds.

Report discussing the effects of suction through slots at the .5 percent chord and 2.5 percent chord stations on the longitudinal aerodynamic characteristics of a 47.5 degree sweptback wing-fuselage configuration with and without flaps. Information about the Reynolds number effects, characteristics of the plain wing, wing with split flaps, extensible leading-edge flaps, the effect of power failure, and the drag coefficients is provided.

The following report describes the charged secondary particles from all presently known decay modes of positive K mesons that have been identified, and the masses of the primaries measured by the momentum-range method.

From introduction: A trip into the Henry Mountains area occupied the days from March 6 to 9, 1951, inclusive, excepting March 7, which was used to examine Reo Hunt's deposit in Poison Spring Wash. Observations were made on stratigraphy, regional geology, and the locations of the known deposits of uranium and vanadium.

The trip into the Henry Mountains Area used to examine the Reo Hunt's deposit s of uranium and vanadium.

A report explaining map symbols for the geologic map of the Northern and Western Flanks of the Black Hills, Wyoming and Montana.