The basic scheme under consideration in this research on stability of closed-loop of the Mark I machine is one in which a voltage proportional to the magnitude of the rf fields in the cavity acts to control rectifier voltage output. It is recognized that such is not the only scheme for maximization of output which may be conceived, but only what seems to be a logical and direct way of attaining such an objective.

The complexing of lanthanum by various anions and weak acids was investigated by observing the light absorption of the complex formed with thenoyltrifluoracetone (TTA). This species showed the properties needed for a satisfactory specgtrophotometric method of analysis.

Technical report covering chemistry of source, fissionable, and structural elements, nuclear chemistry, radio-organic chemistry, chemistry of separations processes, chemical physics, radiation chemistry, and instrumentation at the Oak Ridge National Laboratory for the period ending September 30, 1950. [From Abstract]

Technical report investigating the distribution of rare earth elements between a liquid bismuth-uranium solution and fused KCI-LiCi mixtures. Report warrants further research on the liquid bismuth-uranium-fused salt system due to the benefit of continuous fission removal processes.

Abstract: A comprehensive study was made of various fractionation systems for the fractional separation of barium-radium mixtures. The most efficient and simplest fractionation scheme was chosen on the basis of the thermodynamics of separating the constituents of mixed crystals and of the combining fractions in a system of repeating composition. This scheme was applied to the separation of barium and radium by utilizing the countercurrent batch fractionation of the chromates. The chromate procedure was evaluated by a comparison with the classic methods which employ the fractional crystallization of the halides. The chromate method is more practical on the basis of radium enrichment per fractionation step, control of precipitating conditions, simplicity, and speed of operation.

Introduction: "A number of determination have been made of the half life of polonium-210 by calorimetry. Counting affords an entirely different method of determining half lives and requires only a small amount of activity. Therefore for comparison a half-life determination by counting was undertaken with a sample of approximately 0.5 millicurie of polonium."

From summary: "Various thermal and mechanical properties were measured for sintered tin oxide-matrix compacts which nominally were composed of 99 per cent by weight of tin oxide, SnO2, and one per cent by weight of zinc oxide ZnO...The tin oxide body might be expected to give good service under conditions of severe thermal shock and in an oxidizing atmosphere at temperatures up to 1500°F."

Report discussing progress made by the Chemistry Division (Section C-1) of the Argonne National Laboratory for the months of April, May and June, 1951. Information is divided into "Nuclear Chemistry and Radiochemistry" and "Basic Chemistry".

Abstract: "Steady states decomposition product partial pressures of water exposed to an epithermal neutron flux of about 2 x 10-11, at 235F, were 0.4 to 0.65 psi. Recombination studies were made by adding hydrogen and oxygen gases to water under irradiation at different temperature and flux levels. The data show a significant effect of temperature on the rate of pressure drop of the added hydrogen and oxygen. In operating at two flux levels, 1.2 x 10-11 and 2.0 x 10-11, no difference in the rate of pressure drop with flux could be detected with the instrumentation on the test apparatus."

Report discussing progress made in metallurgy by the Ames Laboratory during the the term from October 1, 1950 to March 31, 1951.

Report discussing the progress made on various chemistry research projects at Ames Laboratory during the period from October 1, 1950 to March 31, 1951.