The following report investigates cross sections for the absorption of slow neutrons of heavy isotopes. The purpose of these measurements was to determine the cross section of an isotope of element 94 for the process of fission by the absorption of a slow neutron, relative to the cross section of U235 for the same process, that is, to measure R.

Abstract: "Samples of dust are collected from the atmosphere with a Mine Safety Appliance Co. electrostatic precipitator and analyzed for uranium by means of a dropping mercury electrode apparatus. Two to three micrograms of uranium can be detected in a cell solution volume of 1 ml. Iron, nickel and chromium present in shop dusts do not interfere. Copper may interfere if present in excess but may be removed by a sulfide precipitation. Directions for preparation of cell solution and operation of the Polarograph are given. The polarographic method described may be used for determination of uranium in samples other than atmospheric dusts."

The following report studies the reactions of vapor phase hydrolysis of the trichlorides of lanthanum, praseodymium, samarium, and americium with gas mixtures of HCl and H2O passing over the solid materials mounted on a cantilever-type quartz fiber microbalance. This report calculates the values of the heats and entropies of the reactions, as well as the heat formation of LaCl3, 1254.9 kcal mol-(-1) that was obtained by determining the heat of the solution of La metal in 1.5M HCl.

The following report discusses measurements for slow and fast neutrons from cadmium coated ionization chambers.

The following report provides data taken from investigations on radiation and the different biologic effects on it.

From abstract: "This report contains the theoretical analysis of a plant to concentrate deuterium from 2 atoms% to 90 atoms% by the NH3-H2 exchange reaction."

The following report discusses the toxicity of fluorine as described in literature on fluorine intoxication and case studies of Roholm's experimental observations.

Abstract: "An accurate calculation is given for the quantity which corresponds to the diffusion length in the theory of the pile. The procedure is to establish a relationship between the diffusion length and the change in thermal utilization from a pile with infinite sides to one with sides of a finite length. The calculation of this change in the thermal utilization is then carried through. Approximation to the answer and numerically exact calculations are given in the report. The results show that for radif very near the optimum values the exact diffusion length is slightly larger than the one obtained from the usual formula...However, over most of the range of radii the exact diffusion length is smaller than the approximate one."

Abstract: "This paper gives an arithmetic method of computing the number of sections required in a catalytic tower to produce a given enrichment. It also tells how to calculate the enrichment of a tower with a given number of sections. The problem of the most economical design of catalytic towers is solved. Methods are given for determining the temperature, the efficiencies of catalyst beds and strippers, the relative production rate, and the water vapor-hydrogen gas ratio which give the optimum combination of operating pressure, cross sectional area, number of sections, and volume of catalyst in the tower. Simple directions as to how to make the calculations are included."

The following memorandum discusses experiments and methods to recover uranium from Colorado-Utah sandstone and leaving the vanadium in the tails, improving filterability.

The following report supplements a previous report by E.R. Saunders and M. C. Carosella and a report by A. J. Gailey and E. O. Brimm based around the same subject. This report describes a number of tests in which leaching temperatures of 115 and 125 C were tried for the extractions of uranium from western ores.

Purpose: "The purpose of the following experiments was to obtain data on the selective extraction of uranium over vanadiur from samples of vanadium ores by leaching with sodium carbonate or sodium bicarbonate solutions, with the object of establishing the time, temperature, and concentration conditions necessary for satisfactory extractions."

Abstract: "The leakage of neutrons from a heterogenous pile with finite aides is calculated developing the method used in CP-992. The change in the fraction of neutrons absorbed by the moderator is obtained using the results of the calculation of the leakage."

The following report was written to replace previous directions submitted in the February 6, 1943 report on the preparation of the solution X(OC₂H₅)₅.

This report was written to replace the directions submitted on April 12, 1943 with improved directions for the preparation of chemical solution X(OC₂H₅)₅.

This report follows research done at the Purdue Research Foundation and Department of Chemistry on fluorocarbons done by the Office of Scientific Research and Development.

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."

Technical report that information has bee obtained on the effect of beta and gamma radiation on the electrical resistance of insulating materials The results are summarized. The recovery to original resistance values has been measured. In general, the initial rate is rapid for the first few hours; the rate then decreases sharply. Certain samples show evidence of complete recovery. Effects on mechanical properties of several plastics has also been studied. Data on gas evolution from several organic materials including those suggested by the physiological shield have been extended to include both beta and deuteron bombardments. Samples of "Press-wood" are being evaluated. The effect of current on the H2O2 production in water containing I- has been studied at several I- concentrations. Water contain-dissolved CO2 shows the presence of oxidant (presumably H2O2). H2O2 has been produced by recoil protons from the scattering of fast neutrons in de-oxygenated water. Radioactive solutions do not greatly affect the applicability the glass electrode providing the electrode is thoroughly washed with distilled water before immersion in the standard buffer solution.

Abstract. The precipitation of Pa233 with MnO2 from a solution of thorium nitrate has been studied in some detail and seems quite satisfactory up to 36 gm Th(HO3)4 4H2O per 100 cc solution. The concentration of Pa233 with respect to the manganese dioxide carrier and the thorium precipitated with the carrier appears to be accomplished quite well by either a series of MnO2 cycles or thorium iodate cycles. Volatility methods for both the separation of Pa233 from the original thorium and for its separation from MnO2 are now under investigation. It has been decided that thorium carbonate will the the thorium compound used in the pile at Site X.

Technical report listing the errata for pages 2, 4, 5, 6, 7, and 8 for report CC-918.

Abstract. Chemical analytical studies of graphite raw materials have revealed new sources of petroleum cokes and pitches of greater purity than those previously used in the manufacture of project graphite. The use of these raw materials of exceptional purity has resulted in an improvement in k of the order of one per cent as compared with the AGOT-AGNT graphite typical of the previous production. A study of the graphitizing process has shown that no dangerous impurities are introduced in the graphite in manufacture; rather, the process actually purifies. furthermore, impurities are distributed homogeneously within the furnace charge; thus the AGOT-AGNT distinction is no longer necessary. A comparison of the methods of graphite testing has demonstrated excellent correlations between chemical analytical data, the results of the function test at Argonne, and the sigma pile experiments. It may therefore be inferred that chemical testing should be an adequate control of the graphite purity. Methods are described for the analysis of ash, B, V, TI, FE, and Ca in petroleum coke, pitch, and graphite.

Technical report: The apparatus for the low pressure combustion method of determining carbon in iron and steel has be redesigned to increase the speed of manipulation. It has been tested by running several thousand determinations and found to yield results in good agreement with Wooten's form of the apparatus. A detailed description of the equipment and its manipulation is given together with an account of experimental studies on the method. Results are also shown for the carbon content of copper.

The critical mass of 94-239 and the corresponding critical dimensions of homogeneous mixtures of 94-239 with various moderating media been calculated as a function of the concentration of 94. A simple transformation makes the figures applicated to92-235. the results are in essential agreement with the preliminary estimated made independently by Oppenheimer and Serber. The problem of the stability of a chain reaction in solution and questions of protection are discussed.

The multiplication factor and minimum pile size for a multiplying pile using UO2 powder of density 1 have been computed. It appears that a k of 1.0177 is possible for a volume ration of V/V001=3.33.