Abstract: A bonding composition comprising a metal oxide melt comprising (a) CaO, (b) SiO.sub.2 and/or Al.sub.2 O.sub.3, and (c) a metal oxide selected from TiO.sub.2, ZrO.sub.2, Cr.sub.2 O.sub.3, HfO.sub.2, Nb.sub.2 O.sub.3 and Ta.sub.2 O.sub.5 is melt-bonded on the surface of a ceramic material, and the ceramic material is bonded to an adherent, if necessary through at least one layer selected from a plating layer, a solder layer, and a buffer layer. In this manner, a strong bonding can be very easily obtained.

Abstract: A porous ceramic material composed of a sintered porous body of a calcium phosphate compound is described. A multiplicity of capillary void paths having a diameter of 1 to 30 .mu.m and a multiplicity of pores having a diameter of 1 to 600 .mu.m are formed in the sintered porous body. At least part of the pores are connected to the exterior space of the sintered porous body through at least a part of the capillary voids. The porous ceramic material is valuable as a medical material, e.g., a substitute or prosthesis for bone or dental root, and also an electronic material and a genetic engineering material.When the porous ceramic material is embedded in a bone defect of human or animals, osteolytic cells, osteoblasts, erythrocytes and body fluid are selectively allowed to intrude through the porous ceramic material while almost no intrusion of osteoclasts and collagen fibers is allowed.

Abstract: A bonding composition comprising a metal oxide melt comprising (a) CaO, (b) SiO.sub.2 and/or Al.sub.2 O.sub.3, and (c) a metal oxide selected from TiO.sub.2, ZrO.sub.2, Cr.sub.2 O.sub.3, HfO.sub.2, Nb.sub.2 O.sub.3 and Ta.sub.2 O.sub.5 is melt-bonded on the surface of a ceramic material, and the ceramic material is bonded to an adherend, if necessary through at least one layer selected from a plating layer, a solder layer, and a buffer layer. In this manner, a strong bonding can be very easily obtained.

Abstract: An inorganic hydraulic material composition containing reinforcing short fibers is sprayed without breakage thereof, by fluidizing reinforcing short fibers in a blast of compressed air, by blending the flow of the reinforced short fibers fluidized in the blast of compressed air with a dry mixture of an inorganic hydraulic material such as cement with an aggregate such as sand in a dry blending region, by introducing the resultant dry blend into a water-mixing region, by mixing the dry blend with water, and by spraying the resultant wet composition through a spray nozzle.

Abstract: A durable hard structure is demolished by a method in which one or more holes are formed in a durable hard structure, filling the holes with an aqueous slurry containing a demolition-facilitating clinker composition consisting essentially of (1) 55% by weight or more of a clinker consisting essentially of 2 to 40% by weight of a calcium-alumino-ferrite solid solution, 60 to 98% by weight of both free lime and free magnesia in the ratio in weight of from 60:40 to 98.3:1.7 and not more than 6% by weight of an inevitable impurity free from (CaO).sub.3 Al.sub.2 O.sub.3 determined in accordance with Japanese Industrial Standard (JIS) R 5202, said clinker being produced at a sintering temperature of from 1200.degree. to 1800.degree. C.

Abstract: A porous ceramic material composed of a sintered porous body of a calcium phosphate compound is described. A multiplicity of capillary void paths having a diameter of 1 to 30 .mu.m and a multiplicity of pores having a diameter of 1 to 600 .mu.m are formed in the sintered porous body. At least part of the pores are connected to the exterior space of the sintered porous body through at least a part of the capillary voids. The porous ceramic material is valuable as a medical material, e.g., a substitute or prosthesis for bone or dental root, and also an electronic material and a genetic engineering material.When the porous ceramic material is embedded in a bone defect of human or animals, osteolytic cells, osteoblasts, erythrocytes and body fluid are selectively allowed to intrude through the porous ceramic material while almost no intrusion of osteoclasts and collagen fibers is allowed.

Abstract: In order to produce a chrysoberyl single crystal displaying a luminous band effect, a mixture of a principal component consisting of beryllium oxide and aluminum oxide in nearly equal molar amounts with small amounts of titanium oxide and coloring metal oxide is sintered or melted and solidified in a non-oxidizing gas atmosphere to provide a raw material bar; the raw material bar is heated in a non-oxidizing gas atmosphere by means of a light condense-heating type floating zone method to grow a chrysoberyl single crystal; and the single crystal is heated so as to allow needle crystals of titanium oxide to be deposited in one orientation in the chrysoberyl single crystal.

Abstract: There is disclosed a method of forming a cast-in-place concrete pile. A demolition-facilitating substance is mounted in an open top confined space above a predetermined level. The demolition-facilitating substance is expansible upon lapse of a predetermined period of time. Concrete is poured into the confined space to cover the demolition-facilitating substance to cast a concrete pile, so that the demolition-facilitating substance is expanded to produce cracks in the concrete pile above the predetermined level.

Abstract: A hardened cement material having enhanced flexural strength, heat resistance, and water resistance prepared from a cement composition comprising 100 parts by weight of a hydraulic cement material containing .gamma.-dicalcium silicate (.gamma.-C.sub.2 S) preferably in an amount of 1% by weight or more and 1 to 20 parts by weight of a water-dispersible polymeric material, and mixed with 5 to 25 parts by weight of water, by a molding procedure and by a heat-hardening procedure at a temperature of from 40.degree. C. to 180.degree. C. while controlling the relative humidity to 20% to 70% and/or applying a pressure of 5 to 15 atmospheres.

Abstract: A cement clinker is produced by utilizing a combustible waste material as a fuel for preheating or calcining a cement material, by using an apparatus comprising a cement material feeder, a preheater or calcinator, a rotary kiln, cooler and means for flowing an exhaust gas from the rotary kiln to the preheater or calcinator, which apparatus is characterized by a heat-decomposer which is located between the preheater or calcinator and the rotary kiln and in which a combustible material is heat decomposed with an exhaust gas from the rotary kiln and resultant combustible gas is burnt in the preheater or calcinator.

Abstract: A method for heating powder material comprising the steps of allowing hot gas from a plurality of hot gas sources separate from each other to flow separately through a plurality of hot gas passages which include a plurality of dust collectors and ducts for connection between said dust collectors, separately charging raw material to be heated through the each duct leading to the dust collector located in the uppermost part of said respective hot gas passages, then uniting the charged powder material, then alternately wandering the united powder material from one hot gas passage to the other hot gas passage, thereby the united powder material is heated by heat exchanging with the respective hot gas streams, and finally discharging the heated powder material through the duct located below the lowermost dust collector.