Abstract: A foam of very small, microscopic bubbles of surfactant, each bubble containing a small quantity of water, is mixed with a water/cement mixture having a water to cement ratio of less than 0.33. The small bubbles have a ball bearing effect on the smaller cement and sand particles, increasing plasticity or flowability and thus reducing the water requirements of the mixture. The foamed cement mixture is laid to form a desired concrete structure, and the bubbles disintegrate or transform to leave voids of similar size uniformly dispersed throughout the concrete structure.

Abstract: A foam producing apparatus has a first mixing chamber with an inner subchamber connected to a supply of gas at a first pressure and an outer subchamber connected to a supply of a foamable liquid at a second pressure higher than the first pressure. A plurality of orifices connect the outer subchamber to the inner subchamber. The foamable liquid is forced from the outer subchamber into the inner subchamber through the orifices and is atomized to form droplets carried by the gas to an outlet. A second mixing chamber is connected to the outlet of the first mixing chamber and is filled with an agitating medium so that droplets propelled through the second mixing chamber are violently agitated to produce the desired foam.

Abstract: Alloys such as U-6Nb are prepared by forming a stacked sandwich array of uraniun sheets and niobium powder disposed in layers between the sheets, heating the array in a vacuum induction melting furnace to a temperature such as to melt the uranium, holding the resulting mixture at a temperature above the melting point of uranium until the niobium dissolves in the uranium, and casting the uranium-niobium solution. Compositional uniformity in the alloy product is enabled by use of the sandwich structure of uranium sheets and niobium powder.

Abstract: An induction furnace for melting and casting highly pure metals and alloys such as uranium and uranium alloys in such a manner as to minimize contamination of the melt by carbon derived from the materials and the environment within the furnace. The subject furnace is constructed of carbon free materials and is housed within a conventional vacuum chamber. The furnace comprises a ceramic oxide crucible for holding the charge of metal or alloy. The heating of the crucible is achieved by a plasma-sprayed tungsten susceptor surrounding the crucible which, in turn, is heated by an RF induction coil separated from the susceptor by a cylinder of inorganic insulation. The furnace of the present invention is capable of being rapidly cycled from ambient temperatures to about 1650.degree. C. for effectively melting uranium and uranium alloys without the attendant carbon contamination problems previously encountered when using carbon-bearing furnace materials.

Abstract: The present invention relates to a metal-oxide ceramic composition useful in induction heating applications for treating uranium and uranium alloys. The ceramic composition is electrically conductive at room temperature and is nonreactive with molten uranium. The composition is prepared from a particulate admixture of 20 to 50 vol. % niobium and zirconium oxide which may be stabilized with an addition of a further oxide such as magnesium oxide, calcium oxide, or yttria. The composition is prepared by blending the powders, pressing or casting the blend into the desired product configuration, and then sintering the casting or compact in an inert atmosphere. In the casting operation, calcium aluminate is preferably added to the admixture in place of a like quantity of zirconia for providing a cement to help maintain the integrity of the sintered product.

Abstract: High strength graphite is manufactured from a mixture of a particulate filler prepared by treating a particulate carbon precursor at a temperature in the range of about 400.degree. to 1000.degree. C., an organic carbonizable binder, and green carbonizable fibers in a concentration of not more than 2 weight per cent of the filler. The use of the relatively small quantity of green fibers provides a substantial increase in the flexural strength of the graphite with only a relatively negligible increase in the modulus of elasticity.