Report issued by the U.S. Bureau of Mines on the investigations conducted on the mica deposits found in Latah County, Idaho. Characteristics and properties of the mica deposits are listed. This report includes tables, and maps.

Report issued by the U.S. Bureau of Mines on the motor fuels sold during the winter of 1945-46. The characteristics of the fuels sold, and the regions they were sold in are listed. This report includes tables, and maps.

This technical progress report details 100 Area activities for the time period of July 16 through July 22, 1946.

At the shutdown of the B Pile, 269 active tubes were discharged and ten poison columns were charged. As a result, the pile was let considerably below critical. The present test described in this report was set up to develop methods of detecting possible changes in reactivity by periodic measurements of neutron flux in the shutdown pile. The irradiation of indium foils in an empty process tube was found to provide a satisfactory method of monitoring the shutdown pile, and was sensitive than the proportional counter with was also tried. The accuracy with which the subcritical condition can be determined is roughly 20%. The uncertainty is due mostly to the irregular arrangement of metal and poison in the unit and the resulting difficulty in representing the neutron flux mathematically.

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The physics of the shutdown of the D pile on July 2 is emphasized in the operation report. The F pile shutdown and operating specifics are also discussed. Water, corrosion, and engineering are reported for the B, D, and F areas.

The present system of classifying slugs intended for canning provides for individual measurement of dimensions on first-run MZ material, but not for their individual weighing. While the total and average weights of this type of material are determined on batches of twenty, this operation is for purposes of accounting only, and no concern is normally attached to the functional aspects of varying weights. It is thought desirable to obtain information relative to this problem. Collection of such information constitutes one of the purposes of the present test. Other purposes include collection of information which will aid in: Evaluating the improvement in overall yield brought about by adoption of the MZ diameter slugs; establishment of more suitable minimum diameter limits for recovered slugs if the present ones prove unsatisfactory; and setting up inspection procedures, if indicated, to cover measurement of dimensions as well as of weights of recovered slugs. This report provides results of this test.

This paper contains a description of the apparatus and theories of the methods successfully used for determining the fast decay periods of near-critical assemblies. The methods described are: (1) the modulation method and (2) the delayed coincidence or Rossi method

Abstract: "Preliminary studies are reported on the use of the ion exchange resins for the adsorptions of purines, uracil, nucleotides, kynurenic acid, and coproporphyrin. Adenine and guanine are adsorbed on IR-100 resin from neutral solution and eluted by HCl. Kynurenic acid and coproporphyrin are adsorbed from neutral solution on IR-4 resin and eluted by HCl. Coproporphyrin is strongly adsorbed on IR-100 resin from either acid, alkaline, or neutral solution. Kynurenic acid is poorly adsorbed on IR-100 resin from neutral aqueous solution. The preliminary application of these procedures to the spectro-photometric study of urine is described."

The following report records the study of albino rats subjected to beta rays and analyzes the skin reactions and metabolic patterns.

Note presenting tests under combined axial load and normal pressure on 29 24S-T aluminum alloy sheet-stringer panels. Empirical formulas were derived for predicting the effect of normal pressure on the strain for buckling of sheet between stringers. Results of buckling, sheet load, strains, buckling, and failure are provided.

Report presenting an investigation of the influences of shank form and pitch distribution on the characteristics of constant-speed propellers as determine from the wakes of eight model propellers. The experiments show that an improvement in efficiency occurs from the substitution of faired shanks for round ones, which is caused by disproportionate local augmentations of thrust and torque. Results regarding a comparison with force tests, method of comparing performance characteristics, effects of shank form, effects of pitch distribution, independence of blade elements, and section lift characteristics are provided.

Report presenting general tank tests of a scale model of the hull of the Boeing XPBB-1 flying boat in tank no. 1. Testing occurred on the forebody alone, the forebody with the afterbody, and the forebody with the afterbody and tail extension, which represented the complete hull. Results regarding the resistance, trimming moment, and length of the planing bottom wetted by the water are provided.

"In order to determine the crystal structure of some currently used heat-resisting alloys, a preliminary investigation of eight leading forged alloys - S816, S590, Gamma Columbium, Hastelloy B, 16-25-6, 19-9 DL, Nimonic 80, and N155 (low carbon) - was conducted by X-ray diffraction methods. The predominant phase in each alloy was found to be a solid solution of the chief alloying elements. The crystal structure of the solid solution was the face-centered cubic type" (p. 1).

Note presenting an investigation of the effects of tip dihedral on lateral stability and control characteristics by flight tests of models in the free-flight tunnel. The results indicate that at high lift coefficients, tip dihedral may cause a lightly damped lateral oscillation, which does not occur with full-span dihedral at similar values of effective dihedral and directional stability.

From Introduction: "Because of the importance of spray height, it is the purpose of the work considered in this report to attempt to determine a correlation for the main spray height in relatively smooth water."

Note presenting a determination of the effects of large variations of the directional-stability derivative and the rotary-damping-in-yaw derivative on the lateral stability and control characteristics of a free-flying model via flight tests. The effects of each parameter were investigated for three values of the lateral-force derivative.

Report presenting flight tests to determine the cooling characteristics of a two-row radial engine at altitude in a twin-engine airplane and to investigate the accuracy with which low-altitude cooling-correlation equations can be used for making cooling predictions at higher altitudes. Satisfactory correlation of the cooling variables was obtained at both altitudes by the NACA-cooling method.

Report presenting the effects of wide variations of dihedral, vertical-tail area, and lift coefficient on lateral stability and control and on general flying characteristics as determined by flight tests in the free-flight tunnel. The geometric dihedral angle and vertical-tail angle were varied in order to vary the effective dihedral angle and directional stability of the model. Results regarding spiral stability, oscillatory stability, lateral control, and general flight behavior are provided.

From Summary: "Bending-stress and bending-moment coefficients are presented for application to design of circular shell-supported fuselage frames of variable cross section for applied radial load, applied moment, and applied tangential load. A ring which is properly reinforced in the region of maximum bending moment is shown to have a structural efficiency higher than that of a similar ring of uniform cross section. The structural efficiency is given in terms of the relative weights of the reinforced and nonreinforced rings."

Report presenting a two-dimensional wind-tunnel investigation made of two interchangeable sealed 0.22-airfoil-chord internally balanced ailerons on an NACA 65(sub 112)-213 airfoil. One aileron tested was of true airfoil contour and the other was modified by partly eliminating the cusp near the trialing edge. Results regarding aileron effectiveness, aileron hinge moments, lift, drag, and airfoil pressure distribution and critical Mach number are provided.

Note presenting performance parameters for jet-propulsion engines developed from the concepts of flow similarity, inertia forces, elastic forces, viscous forces, and thermal expansions of the working fluid. The analysis relates performance to the geometry of the boundaries, Mach number, Reynolds number, and total-temperature ratio.

Note presenting an application of the theory of Lagrangian multipliers to the problem of finding both upper and lower limits to the true compressive buckling stress of a clamped rectangular plate.

Report presenting aerodynamic testing of 12.208-foot-diameter two-blade hollow steel propellers before and after alteration for thermal de-icing in the 16-foot high-speed tunnel to determine the effect of the alterations on propeller efficiency. The propeller had Clark Y blade sections tested on a 2000-horsepower dynamometer at a range of blade angles and airspeeds. Results regarding accuracy, the effect of the alteration, effect of internal air flow, effect of compressibility, and coefficient of mass flow of de-icing air are provided.