Abstract: An inert gas bubble-actuated molten metal pump is located in a metal-melting furnace to effect circulation of molten metal throughout the furnace. The inert gas employed to actuate the molten metal pump is captured beneath a heat-resistant and flame-resistant cover located above the exit port of the pump and over a substantial portion of the molten metal, thereby to prevent splashing, spattering, and disruption of a thin protective layer or skin of oxidized metal at the surface of the molten metal as well as to provide a non-oxidizing atmosphere at the surface of the molten metal beneath said cover. In this manner and by this combination, the inert gas is employed most efficiently and economically.

Abstract: A composition of methacrilic resin which constitutes a resin possessing an outstandingly easy release from the mold of injection molding machine without defilement of the stamper and the peripheral ring of stamper holder, and therefore proves suitable material for replica of raser disk is provided. This methacrylic resin composition is characterized by having incorporated in a methyl methacrylate copolymer the three lubricant components, i.e. a higher alcohol (x), a monoglyceride of a higher fatty acid (y), and a paraffin (z), in such amounts that the individual contents of (x), (y), and (z) are in the respective ranges of 0.05 to 0.2% by weight, 0.05 to 0.2% by weight, and 0.02 to 0.15% by weight and the total content of (x), (y), and (z) is in the range of 0.2 to 0.35% by weight.