Abstract: The invention has been developed to find out a blemish on the surface of a disk (in particular, a stroke mark in the CSS area) without opening up a hard disk. Furthermore, the invention is intended not to cause extra labor or cost in fabrication of hard disks, and to be applicable to hard disk already in widespread use. To this end, with an acoustic inspection method of the invention, inspection of whether or not a blemish has been inflicted on the surface of a disk (in particular, a blemish in the CSS area) can be conducted without opening up the hard disk by detecting vibration occurring when a head of the hard drive comes into collision with the blemish on the disk from vibration propagating to a housing of the hard disk.

Abstract: A foundry exothermic assembly is formed by mixing hollow glass microspheres and an inorganic or organic binder with matrix forming constituents including an oxidizable metal, an oxidizing agent, a foundry refractory aggregate and, optionally, a pro-oxidant, and shaping and curing the mixture. The hollow glass microspheres are dispersed and embedded in the assembly matrix.

Abstract: A riser sleeve has a sleeve body and an evaporative pattern fit into the sleeve body to pass through a side wall thereof. The evaporative pattern is shaped to enable the casting, integrally with the riser cast by the sleeve body, of a projecting portion capable of receiving a wedge blade of an openable wedge blade type riser breaker. Even a top riser can therefore be broken off of the main casting at a neck portion by an opening force applied to the wedge blades of the riser breaker without the use of a special jig.

Abstract: A process for producing a foundry exothermic body such as an foundry exothermic riser sleeve includes the steps of preparing a raw material mixture whose components include one or more powdered/granular refractories, one or more powdered/granular exothermic materials, one or more powdered/granular oxidants and one or more powdered pro-oxidants, mixing thermosetting phenol resin with the raw material mixture to coat grain surfaces of the raw material mixture with thermosetting phenol resin and obtain a thermosetting phenol resin coated raw material mixture, and using the shell molding process to form and cure the thermosetting phenol resin coated raw material mixture into a foundry exothermic body of prescribed shape.

Abstract: A riser sleeve with a breaker core comprises a sectionally V-shaped riser sleeve having a bottom opening and a breaker core having a central opening and attached to the bottom of the riser sleeve. The inner diameter D.sub.3 of the central opening of the neck-down core is substantially the same as the inner diameter D.sub.2 of the bottom opening of the riser sleeve, and the outer diameter D.sub.5 of breaker core is substantially the same as or larger than the outer diameter D.sub.4 of the bottom of the riser sleeve. The riser sleeve with breaker core greatly reduces the amount of finishing that the cast product requires after casting.

Abstract: Metallurgical formed articles, such as a metal casting mold or hot top sleeve, which emit fragrance when heated and formed from refractory material containing powder or granular vegetable substance which emits fragrance when heated, and method of producing the same.