Abstract: Studies were made of the air-borne contamination present during the operation of reducing plutonium tetrafluoride powder to the metal. Equipment design changes were made and operation technique changes were made until the amount of contamination present during operations was well below tolerance levels.

Abstract. Experimental work was carried out to improve material conversion efficiency and to reduce handling costs inherent in the present process for production of high purity calcium. Charges up to 54 pounds were handled successfully in the equipment available. Material losses were reduced and more complete removal of alkali and alkaline earth metals was effected by controlled pressures of inert gas and by melting under positive pressure of Argon.

A good determination of the resonance absorption of uranium when admixed with various substances is necessary so that calculations can be made on the efficiency of homogeneous piles. The original experiments along these lines were undertaken by Creutz, Jupnik, and Snyder (C-116) and consisted of experiments on the resonance capture in pure U, UO2, U3O8, and one experiment on capture in a mixture of U3O8 and graphite. These experiments were done at the cyclotron in Princeton and consisted of determining the ratio of the twenty-three minute activity of uranium to an iodine monitor placed in some position with respect to the sample. By using spheres of different radii both the volume and the surface absorptions were measured. It was considered very desirable to extend these measurements to mixtures containing large amounts of graphite to uranium and also to investigate other substances containing hydrogen and deuterium. In addition it was decided to use both iodine and gallium monitors in the experiments. While the experiments were in progress, an absorption curve for uranium metal was made by Marshall using iodine and gallium detectors, which showed that there was a certain amount of overlapping of resonance levels of uranium and iodine.

It was desired to determine a method of evaporating boron to form a rather pure uniform tenacious coat of specified thickness. These coats are needed as monitoring films for neutron intensities, particularly in steel ionization cylinders. The most satisfactory method of evaporating boron employed a graphite filament. A mixture of amorphous boron and Carbenoid A was painted onto the filament which was then heated by electrical resistance method to 2300 degree C at which temperature the boron evaporated. Opaque films with purities up to 98% boron or better could be deposited by this method. Much heat was liberated by the filament, and it was found necessary to cool the steel cylinders during evaporation to prevent alloying of boron with the steel. Cathodic deposition also proved satisfactory for producing high purity films; this method has the advantage that little or no heat is produced during the process, but requires much time. Other less efficacious methods of depositing lighter films of born were developed; these are included in the following discussion.

Report discussing experiments investigating the effects of radiation and metal toxicity on the function of the liver, kidneys, adrenals, and bone marrow of experimental animals.

This report for December, 1947 describes progress in ore dressing and pyrometallurgical studies, chemical work on phosphates, and analytical work.

This report for March, 1947 describes progress regarding chemical and spectrographic analysis, chemical work, physical methods of analysis, and ore dressing and pyrometallurgical studies,

This report for January, 1947 discusses progress regarding ore dressing studies, pyrometallurgical work, chemical work, chemical and spectrographic analysis, and physical methods of analysis.

A method of calibrating the static-pressure source of a pitot static airspeed installation on an airplane in level flight, dives, and other maneuvers at high altitude and at transonic and supersonic speeds is described. The method principally involves the use of radar-phototheodolite tracking equipment. The various sources of error in the method are discussed and sample calibrations are included.

Memorandum presenting high-speed wind-tunnel tests of four thin NACA 63-series airfoil sections with a design lift coefficient of 0.2 with the uniform-load type of mean camber line to determine the effectiveness of forward movement of the minimum-pressure position in improving the high-speed lift characteristics of low-drag airfoils. Results regarding the tunnel-wall effects, lift coefficient, drag coefficient, and moment coefficient are provided.

Report presenting supersonic-tunnel tests of two models of similar supersonic airplane configurations at Mach numbers of 1.55, 1.90, and 2.32 to determine values of the drag, lift, pitching moment, yawing moment, and side force. The models were similar except for the vertical wing location relative to the body axis and horizontal tail; one had a high wing and one had a low wing. Results regarding the precision of data, Reynolds numbers of tests, results at the different Mach numbers, and Schileren photographs are provided.

Report presenting the tumbling characteristics of dynamic models of 14 airplane designs in the free-spinning tunnel for various loadings and configurations. Conventional airplanes were not found to tumble, but tailless and tail-first airplanes might depending on the amount of static longitudinal stability. Results regarding the effect of dimensional and mass characteristics, effect of controls, use of parachutes as a tumble-recovery device, accelerations, and possibility of pilot escape are provided.

Report presenting the transonic drag characteristics of a series of wing-body combinations and their component parts using the free-fall method. The configurations examined had wings of various sweeps and thickness ratios mounted on identical bodies of fineness ratio 12.

Report presenting a flight investigation of rocket-powered models at high-subsonic, transonic, and supersonic speeds to determine the zero-lift drag of fin-stabilized bodies of revolution differing in maximum diameter. All bodies had 6.04 fineness ratio and cut-off sterns with equal base area. The most favorable location out of the 20-percent, 40-percent, and 60-percent positions were evaluated for different speeds.

The aerodynamic characteristics of 34 miscellaneous airfoils tested in the Langley two-dimensional low-turbulence tunnels are presented. The data include lift, drag, and in some cases, pitching-moment characteristics, for Reynolds numbers between 3.0 x 10 (exp 6) and 9.0 x 10 (exp 6).

"An investigation was conducted to determine the cause of failures in the seventh- and tenth-stage blades of an axial-flow compressor. The natural frequencies of all rotor blades were measured and critical-speed diagrams were plotted. These data show that the failures were possibly caused by resonance of a first bending-mode vibration excited by a fourth order of the rotor speed in the seventh stage and a sixth order in the tenth stage" (p. 1).

Report presenting data from 95 subsonic flutter tests conducted in the flutter research tunnel on untapered cantilever wings with sweepback angles of 0, 45, and 60 degrees and carrying a single concentrated weight. The primary purpose of the investigation was to present experimental information to be used to evaluate analytical procedures for determining the flutter speed of weighted sweptback wings. The dynamic pressure, flutter velocity, Mach number, natural and flutter frequencies, and phase-angle relationships of the stresses for the natural and flutter frequencies are presented.

A method has been developed for interpreting v-g records taken during the course of commercial transport operation. This method involves the utilization of fairly simple statistical procedures to obtain "flight envelopes," which predict that, on the average, in a stated number of flight hours, one value of airspeed will exceed the envelope, and one positive and one negative acceleration increment will exceed the envelope with equal probability of being experienced at any airspeed. Comparison with the actual data obtained from various airplanes and from various airlines indicates that these envelopes predict the occurrences of large values of acceleration and airspeed with a high degree of accuracy.

"Data obtained from an extensive investigation of the cooling characteristics of four multicylinder, liquid-cooled engines have been analyzed and a correlation of both the cylinder-head temperatures and the coolant heat rejections with the primary engine and coolant variables was obtained. The method of correlation was previously developed by the NACA from an analysis of the cooling processes involved in a liquid-cooled-engine cylinder and is based on the theory of nonboiling, forced-convection heat transfer. The data correlated included engine power outputs from 275 to 1860 brake horsepower; coolant flows from 50 to 320 gallons per minute; coolants varying in composition from 100 percent water to 97 percent ethylene glycol and 3 percent water; and ranges of engine speed, manifold pressure, carburetor-air temperature, fuel-air ratio, exhaust-gas pressure, ignition timing, and coolant temperature" (p. 207).

From Summary: "The development and the use of a chart for estimating the pressure losses in jet-engine combustion chambers are described. By means of the chart, the pressure losses due to fluid friction and to momentum changes in the air flow accompanying combustion can be separately evaluated. The over-all pressure losses computed from the pressure-loss chart are within 7 percent of the experimental values for the three types of combustion chambers considered herein."

"An experimental investigation, using microscopic observation and color motion photomicrographs of the action, was conducted to determine the cause of fretting. Glass and other noncorrosive materials, as well as metals, were used as specimens. A very simple apparatus vibrated convex surfaces in contact with stationary flat surfaces at frequencies of 120 cycles or less than l cycle per second, an amplitude of 0.0001 inch, and load of 0.2 pound" (p. 135).

This report for May, 1947 describes progress regarding analytical work, chemical work, beta-counting methods of analysis, ore-dressing and pyrometallurgical studies, and pyrometallurgical work.

Summary: "Water containing 1.8% D2O was distributed between the two liquid phases formed with triethylamine at 20 and 35 C. The triethylamine was removed from each phase by aseotropic distillation with benzene before analyzing the water by determining its density with a quartz float. The ratios of the concentrations of the D2O in the water layer to that in the amino layer were 1.007 and 1.004 at 20 and 35, respectfully. The differences from unity are about the same as the errors of analysis."

The emf of galvanic cells at high temperatures was measured using uranium metal in equilibrium with its chloride as one half of the cell, the other half of the cell being some reference electrode such as silver - silver chloride. Several designs of cells tried are described. A value of 2.83 volts/eq. at 1170[degree]K and also at 990[degree]K is considered as the most probably value for the potential of the uranium halide couple.