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.

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.

This report discusses the poisoning effectiveness and uniformity of the first production batch of 33 myrnalloy slugs which was tested in the 305 Test Pile on February 26, 1946, prior to charging into the D Pile in accordance with Production Test No. 105-49-P, supplement A.

Abstract: The geometrical structure of the uranium halides has been studied from a theoretical viewpoint. This theoretical consideration tends to indicate that the pentavalent uranium halides are geometrically but not energetically capable of existence except as double halide compounds of hexavalent and tetravalent uranium.

From introduction: "This paper presents data on the effect of x rays on tissue metabolism."

An investigation of the performance of several propellers on the YP-47M airplane at high blade loadings has been conducted in the Cleveland altitude wind tunnel at the request of the Air Materiel Command, Army Air Forces. As part of the program, a study was made of a Curtiss 836-14C2-18R1 four-blade propeller. The investigation was made for a range of power coefficients from 0.10 to 1.00 at free-stream Mach numbers of 0.30, 0.40, and 0.50 for density altitudes from 10,000 to 45,000 feet, engine powers from 150 to 2500 brake horsepower, and for engine speeds from 1000 to 2900 rpm.

At the request of the Bureau of Aeronautics, Navy Department, investigations of the static-pressure losses and total-head distributions of the Westinghouse X24-C-2 inlet screen were made in the induction aerodynamics laboratory at Langley. The screen was investigated in two configurations, both before and after rounding the leading edges of the vanes. Investigations were conducted through air flows up to about pounds per second.