Abstract: A rotary tool for cutting, drilling, grinding, or polishing metallic or non-metallic materials is made of a compact material, which consists of an inorganic fiber reinforced plastic containing 50 to 81 volume % of inorganic long fibers selected from the following group: alumina fibers, boron fibers, silicon carbide fibers, and silicon nitride fibers, the remaining portion of the compact material consisting of a thermosetting resin matrix.

Abstract: An externally threaded fiber-reinforced plastic member comprising a shank and an integral thread on the exterior surface on the shank, in which a plurality of first strands are arranged substantially in parallel and extending longitudinally of the axis of said shank and a plurality of second strands are arranged substantially in parallel and substantially in perpendicular relation to said first strands has a unique interior structure in which most of the resin-impregnated fiber-filaments existing within the thread extending substantially in a plane including a cross-section of the threaded member are those extending continuously from and laterally of the shank into the thread. Such an externally threaded member having satisfactory mechanical strengths, and can be produced with high productivity and at low cost, utilizing the pultrusion technique, although the production method is not limited thereto.

Abstract: An internally threaded fiber-reinforced plastic member comprising a hollow body which has a body portion and a central bore, in which at least one crossing pair of unified groups of resin-impregnated strands are arranged substantially in perpendicular relation to the axis of the member, has been found to be extremely excellent in mechanical strength. Such an internally threaded member can be produced with high productivity and at low cost, utilizing filament winding technique, although the production method is not limited thereto.

Abstract: An artificial reef assembly construction is disclosed which comprises, in combination, an artificial reef assembly comprising a plurality of reef units each comprising a hollow structure and a predetermined number of floaters, each floater comprising a body casing having an inner chamber partitioned so as to be fluid tight by means of at least one partition wall to have a plurality of air chambers, the floaters being releasably secured into the hollow structures of reef units, at least one of the plurality of air chambers having at least one openable portion. The artificial reef assembly construction with its floaters filled with air can be floated on the surface of the sea and easily towed to a desired location, where by only opening at least one openable portion of of at least one of the air chambers the artificial reef assembly can be easily submerged while causing the floaters to be automatically released from the artificial reef assembly.

Abstract: A novel artificial reef unit comprising a hollow structure with its peripheral framework having oblique lattice pattern windows arranged in specific relationships with fiber-reinforced plastic bands in the framework is found to be durable in the marine environment and extremely effective for gathering fish, shellfish and the like. Representative of the specific relationships include requirements that the peripheral framework of the hollow structure has a total band surface area of 15 to 50% based on the imaginary entire surface area of framework and that the windows in the framework each have an open area of 0.1 to 0.8 m.sup.2.

Abstract: Fire retardant unsaturated polyester resin compositions are prepared by intimate mixing of unsaturated polyester resins and 100-900 parts by weight of hydrated magnesium carbonate per 100 parts by weight of polyester resin. Such compositions when reinforced with glass are suitable for use in building fire retardant interiors.