As a result of a wide variety of studies on photosynthesis in living plants and plant fragments, together with the development of photosensitive, photovoltaic junctions in inorganic crystals and the discovery and exploration of semiconduction in organic molecular substances, a suggestion has been made that the primary quantum conversion process in photosynthetic tissues involves the creation and separation of charge to opposite sides of an asymmetrically-constructed lamina, followed by the trapping of both the electrons and the holes which then lead to their respective chemical processes, namely reduction of carbon dioxide and oxidation of the water to oxygen. This has led us to study model systems as semiconductors with a view to creating an organic photovoltaic junction.

Radiation Damage to the graphite moderator has played an important role in the history of reactor operation at Hanford. The operational problems, potential and real, which result from dimensional instability, stored energy, and gasification, as well as the solutions to these problems are discussed. The key to the graphite problems is operating temperature and its control. At present, stack expansion remains in the fringe regions of the original reactors, which coupled with the contraction of the central region gives rise to curvature problems in the top portion of the reactors. Stored energy is not a safety hazard because the release spectrum is such that a spontaneous and self sustained release cannot occur. Oxidation of the graphite moderator is controlled by maintaining operating temperature of the stack such that no significant amount of oxidation occurs.

Pyrometallurgical methods studied are liquation, self-drossing and filtration, slagging by the addition of oxide, carbide, or halide, liquid metal extraction, complete conversion to halide, followed by filtration and selective reduction of the plutonium, and electrorefininng. Experimental techniques and results are presented for each method. (auth)

The large class of amorphous insoluble hydrous oxides has interesting ion exchange properties. These materials have high capacities and suitable exchange rates and may therefore be used in packed columns in typical chromatographic (ion exchange) manner. Hydrous oxides may exhibit either cation exchange or anion exchange properties, or both. The type of adsorption depends on the element on which the oxide is based, on the acidity of the medium and, to some extent, on the ion adsorbed. Though some of the most acidic oxides are soluble (e.g., P/sub 2/O/sub 5/) or easily dispersible (e.g., MoO/sub 3/ WO/sub 3/) their intrinsic cation exchange properties may be utilized by incorporating them in excess into an insoluble matrix, i.e., by preparing certain insoluble acidic salts. Some of the materials with cation exchange properties may be used even with extremely small columns - for the separation of the alkali metals from each other - or of the alkaline earths. The specificity of these compounds for cesium in acidic solutions permits the almost unique isolation of this element from properties all others. Those oxides with anion exchange properties also have unusual selectivities compared with the organic ion exchangers. Oxides based on Bi(III) have high selectivities …

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Radiochemical studies of the fast neutron fission of U/sup 235/ and U/sup 238/ have been made in the mass region beyond mass 143 with two neutron energy distributions. These studies provide measurements of the relative fission yields of several chains in the rare earth group in fission of U/sup 235/ and U/sup 238/ caused by neutrons with an energy distribution very close to unmoderated fission neutrons and by neutrons with an energy distribution peaked at 8 Mev. The increased contribution of very asymmetric modes of fission as the energy of the compound nucleus is increased is clearly shown by the results. In the fission of U/sup 238/ the yield at mass 161 is increased 2.9 times at the higher neutron energy. No previous measurements have been published on radiochemical studies of the fission of U/sup 238/at these neutron energies beyond mass 144 except at mass 156 for the lower neutron energy. (auth)

This paper discusses research and development effort on a direct-cycle air-cooled nuclear reactor and propulsion equipment. The reactor experiment was designed, constructed, and tested during the period 1953 to 1956 to prove the feasibility of operating a turbojet engine from the heat produced by an air-cooled reactor. A description is given of the reactor, turbomachinery, shielding, control system, and associated equipment used in the first propulsion system test which was run in 1956. The system consisted of a modified J-47 turbojet engine arranged so that compressed air from the compressor was ducted through a shielded reactor and a chemical combustor in series before passing through the turbine and exhaust nozzle. The experimental reactor was based on a unique design concept in which water moderated at low temperature is contained in an aluminum core structure. The air-cooled metal fuel elements containing enriched uranium were arranged in passages running through the reactor. Thermal insulation was provided to protect the aluminum structure from the high temperature fuel elements and air, and to reduce heat losses to the moderator water. The entire reactor shield and turbojet assembly was mounted on a four-rail flat car for easy transfer by a shielded locomotive from the test …

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A brief review of fast electronics is given, leading up to the present state of the art. Cherenkov counters in high-energy physics are discussed, including an example of a velocity-selecting Cherenkov counter. An electronic device to aid in aligning external beams from high-energy accelerators is described. A scintillation-counter matrix to identify bubble chamber tracks is discussed. Some remarks on the future development of electronics in high-energy physics experiments are included.