Report issued by the U.S. Bureau of Mines on the exploration of the Mount Hope mine. Analysis of samples obtained from core-drilling are listed. This report includes tables, maps, and illustrations.

Report presenting knock testing of a sensitive fuel and a relatively insensitive fuel in a full-scale air-cooled cylinder. Six engine variables were investigated: fuel-air ratio, compression ratio, inlet-air temperature, spark advance, exhaust pressure, and cylinder temperature.

Note presenting three internally cooled exhaust valves with the same external dimensions but different throat designs were investigated to determine a method of obtaining increased coolant-flow area with increasing stresses. The valves were statistically loaded to simulate stresses in the throat region caused by valve closure.

Tests made prior to beginning operation of the 100 Areas showed that the cooling water had a tendency to deposit a film upon the slug and tubs surfaces. This film would manifest itself as an increase in the pressure drop through the tubes and its most serious affect would be the resultant decrease in the slug to water host transfer coefficient which would increase the slug surface temperature, causing greatly accelerated corrosion rates. It was thus proposed to study film formation an a production test. This report discusses this test.

This technical progress report details 100 Area activities for the time period of August 13 through August 19, 1946.

It was agreed during a meeting on July 10, 1945, investigation should be made to determine how fast and in what fashion the temperature of the effluent water from the 100 Areas is dissipated in the Columbia River. A preliminary report on these investigation was issued March 1, 1946: it discussed the testing techniques developed and the results of a survey made at the 100-B Area. Following a review of the data and tentative conclusions resented therein, it was agreed to extend the survey using similar technique: to the D and F Areas, and to determine if the tentative conclusions were substantiated.

The weekly progress for D and F piles is given. Status of the test to determine the cause of white deposits on the horizontal control rods of the F pile is given. Also discussed are studies of process water control and pressure drop, corrosion, and graphite expansion. Test results indicate that graphite expansion has not seriously limited discharge of process tubes.

This report details 100 Area reactor operation for the time period of August 6 through August 12, 1946.

None

Abstract. A satisfactory method has been found for dissolving thorium metal and thorium oxide in heat-treated 25-12 stainless steel vessels without excessive corrosion of the vessels. The dissolution medium consists of strong HNO3 containing a small amount of fluoride or fluo-silicate. the fluoride required has no harmful effects on a subsequent solvent-extraction step for a separation of uranium isotopes from the dissolved thorium.

None

None

A theorem is derived which is useful in the analysis of neutron problems in which all neutrons have the same velocity. It is applied to determine extrapolated end-points, the asymptotic amplitude from a point source, and the neutron density at the surface of a medium. Formulas for the effect of finite tampers are derived by its aid, and their accuracy is discussed.

Methods are developed for estimating the effect on a critical assembly of fabricating it as a lattice rather than in the more simply interpreted homogeneous manner. An idealized case is discussed supposing an infinite medium in which fission, elastic scattering and absorption can occur, neutrons of only one velocity present, and the neutron m.f.p. independent of position and equal to unity with the unit of length use. (auth)

Abstract: "Several chemical and physical characteristics of over seven hundred charges are computing with their performance in the process units. No correlation is attainable."

Data are presented of the flow conditions in the vicinity of an NACA D sub S -type cowling. Tests were made of a 1/2 scale-nacelle model at inlet-velocity ratios ranging from 0.23 to 1.02 and angles of attack from 6 deg to 10 deg. The velocity and direction of flow in the vertical plane of symmetry of the cowling were determined from orifices and tufts installed on a board aligned with the flow. Diagrams showing velocity ratio contours and lines of constant flow angles are given.

Report presenting an investigation to determine the effect of the location of the diffuser vanes with respect to the supercharger outlets and the effect of flow conditions at the impeller inlet on the air-flow distribution in the outlets of the engine-stage supercharger of an 18-cylinder double-row radial aircraft engine. The effect of flow conditions at the impeller inlet was investigated by distorting the flow at the inlet and noting the effect in the supercharger outlets. Results regarding the diffuser effect and inlet effect are provided.

"The theory of small disturbances is applied to the calculation of the pressure distribution and drag of a closed body of revolution traveling at supersonic speeds. It is shown that toward the rear of the body the shape of the pressure distribution is similar to that for subsonic flow. For fineness ratios between 10 and 15 the theoretical wave drag is of the same order as probable values of the frictional drag" (p. 1).

Report presenting the load capacities of four aluminum-alloy radial-engine crank-pin bearings determined in a centrifugal bearing test machine. Chemical analysis made after the bearings had been tested to failure showed that the actual composition of each aluminum alloy was different from the chemical specifications.

From Summary: "A method of increasing the compressive strength of 24S-T aluminum-alloy sheet by flexure rolling was investigated. In this method, the sheet was alternately bent and then straightened by rolling a four-step procedure. The results showed that the greatest increase was in compressive yield stress in the with-grain direction regardless of the direction of rolling; the increase was greater as the radius of flexure rolling became smaller and as the number of steps was increased. The tensile properties, however, were little affected."

Report presenting an investigation of the cooling of an 18-cylinder, twin-row, radial, air-cooled engine in a high-performance pursuit airplane for variable engine and flight conditions at a range of altitudes to provide a basis for predicting high-altitude cooling performance from sea-level or low-altitude test results.

Report presenting experiments to determine the shearing rigidity of curved panels under compression, particularly in that region of loading where the panels are in a buckled state. For the preliminary tests four, and for the final test series eight, circular cylinders were built of aluminum alloy sheet. Results regarding the uniformity of compressive strain, buckling of the panels, distribution of shear strain, calculation of the effective shear modulus, shear rigidity versus compressive strain curves, nondimensional shear rigidity curves, and failure of the cylinders are provided.

Report presenting testing regarding the effectiveness of ducted head baffles in reducing temperatures of rear-row exhaust-valve seats using a two-row radial engine. Two types of ducted head baffle were investigated on a test stand and the better of the two was tested in flight. Results regarding the preliminary test stand investigation with two baffles and a flight investigation on five rear-row cylinders are provided.

Note presenting the Izod-impact strengths and flexural properties of several types of plastic laminates, which are either in use or have potential application in aircraft structures and parts, and were determined at different temperatures. The materials investigated were unsaturated-polyester laminates reinforced with glass fabric and phenolic laminates reinforced with asbestos fabric, high-strength paper, rayon fabric, and cotton fabric.