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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.

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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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This paper will describe a telemetry system which has a bandwidth of 250 mgacples, the uses to which it has been put and possible future uses.

Present-day knowledge concerning the molecular structure of supercritical fluids is briefly reviewed. It is shown that liquid-like and gas-like phases may coexist at supercritical pressures, although they may not be in equllibrium with each other. it is postulated that on the basis of the coexistence of these two phases a "boiling-like" phenomenon may provide the mechanism of heat transfer to supercritical fluids at high heat fluxes and certain other conditions. An unusual mode of heat transfer was actually observed at supercritical pressures during tests which produced the high heat fluxes and other conditions under which such "boiling" would be expected. The tests and the various conditions are briefly described. An emission of high-frequeney, high-intensity sounds usually accompanied these tests. It is shown that similar screaming sounds were heard during boiling at subcritical pressures, giving further support to the hypothesis that "boiling" may occur at supercritical pressures. A seeond possible explanation for the unusual mode of heat transfer is based on boundarylayer stability considerations. At high heat fluxes large density differences exist between the bulk of the fluid and the fluid in the boundary layer near the wall. A breakdown of the boundary layer may be caused by the build-up of …

Procedures are described for both a titrimetric and a gravimetric determination of hafnium in aluminum -hafnium alloys. The gravimetric procedure is used if the hafnium is to be recovered; otherwise, the titrimetric procedure is preferred. The sample is dissolved in aqua regia. Any undissolved hafnium is taken into solution via pyrosulfate fusion. The hafnium is separated from the aluminum and contaminants in the aluminum by precipitation as the mandelate. In the gravimetric procedure the hafnium mandelate is heated to the oxide, then weighed. In the titrimetric procedure the mandelate is destroyed with nitric, sulfuric, and perchloric acids. The hafuium then is determined by adding a measured excess of EDTA and back titrating the excess EDTA with a standard bismuth solution to a xylenol orange end point. (auth)

This paper presents, in two parts, a general discussion of fused-salt heat transfer. The first part is a report on current experimental results with three new salts - an alkali metal-base fluoride, a zirconium-base fluoride, and an alkali metal nitrate-nitrite mixture known as 'HTS'. In the second part fused salts are compared with liquid metals on the basis of their heat transfer effectiveness as reactor coolants. An analysis is presented for a general solid fuel-element reactor which transfers its heat to a fluid boiling on the outside of the heat exchanger tubes. The results show that fused salts can be as good heat transfer media as liquid metals. (auth)