Abstract: Process for the production of concrete tiles by cutting a block of concrete mixture, characterized in that the block of mixture is subjected to a preliminary curing at room temperature for a duration of at least 24 hours or to a low-pressure steam treatment at a temperature <100.degree. C. until the compression strength reaches a value of at least 20 MPa, and to a second treatment with steam in an autoclave. The cement tiles thus obtained may be bonded to the floor using a normal setting layer of cement mortar, without giving rise to any problems of detachment.

Abstract: A fuel management system for reducing pollution when an internal combustion engine is at idle includes a flow control valve located between the fuel tank and the float bowl of the carburetor to reduce the amount of fuel entering the carburetor. A pump is also provided between the fuel tank and the float bowl for removing the existing fuel from the float bowl and conveying it back to the fuel tank when the engine is at idle. The flow control valve in its reduced flow state and the pump are inactivated until the engine reaches a predetermined pressure at which time the existing fuel would be removed by the pump from the float bowl and the flow control valve would permit only a reduced flow of fuel to be conveyed to the float bowl sufficient to keep the engine running.

Abstract: A system for delivering warm humidified air to a patient. Pressurized air is heated to a predetermined temperature and a portion of the heated air is humidifed to substantially 100% relative humidity. The warm humidified air is delivered to a patient through an inner one of a pair of coaxial hoses. The remaining heated air is passed through an annular passage between the two hoses to maintain the temperature and vapor content of the warm humidified air delivered to the patient.