Abstract: A process of repairing a refractory body, including the steps of a. introducing combustible particles into a first gas stream containing no more than 18% oxygen by volume; b. causing an oxygen-rich gas stream to flow through a particle entrainment zone into a reaction zone adjacent a refractory body to be repaired so as to produce an aspirating effect within the particle entrainment zone effective to induce a flow of the first gas stream containing the combustible particles into the particle entrainment zone and through to the reaction zone; and c. projecting the combustible particles entrained in the oxygen-rich gas stream against the refractory body to cause oxidation of the combustible particles in the reaction zone adjacent the refractory body and generate sufficient heat for one of dressing the refractory body or forming a refractory weld mass thereon.

Abstract: A centrifugal molding method which can smooth the inner surface of the resin concrete layer of a resin concrete pipe or of a composite pipe having a resin concrete layer even without using any special sand conditioning mechanism and which is high in productivity includes producing a composite pipe having a resin concrete layer or producing a resin concrete pipe by moving an arm member of a pipe material feeding device forward and backward axially through a pipe forming outer mold rotating about an axis thereof and by feeding pipe materials from a discharge port formed in a front end of the arm member. The resin concrete layer is formed by feeding resin and aggregate to a mixing portion provided at the front end of the arm member through separate feed routes, mixing the two in the mixing portion and discharging the resulting mixed resin concrete material from the discharge port.

Abstract: A prestressing arrangement and technique for the manufacture of prestressed bodies or structures includes shape memory material members. According to one aspect of the invention, the prestressing arrangement includes a tensile member in series with a shape memory material member. The formable material is shaped around the members and fixed in form. The shape memory material is then shrunk by heating it above its characteristic threshold temperature, placing the members in tension and the fixed material in compression. According to another aspect, the shape memory material member is secured in a tube. Prestressing is achieved in the tubular prestressing arrangement by lengthwise expansion of the shape memory material member prior to fixing the material of the body being formed, and then after fixation, releasing the stress on the shape memory material member, leaving the tube in tension to exert compressive forces on the fixed material.