Abstract: An internal combustion engine and a method of operating same, comprising a combustion chamber having main and auxiliary sections. The air-fuel mixture compressed in the combustion chamber causes turbulence and swirling of the mixture in the auxiliary section. On ignition, the initial combustion rate in the auxiliary section is limited by the centrifugal force on the flame. The jet of gases rushing out of the auxiliary section is not swirled and controls the rate of burning in the main section to reduce peak flame temperature and hence, to reduce CO, NO.sub.x and HC emissions.

Abstract: The thermal reduction process for producing metals such as aluminum in a reactor utilizes a dispersed discharge to provide the heat of reaction within the reaction zone in the presence of aluminum vapor to maintain the temperature in excess of 2000.degree. C. The aluminum oxide powder and a reductant in a gaseous medium are introduced with a tangential component into the reactor to create a vortex motion. A minimum turbulence level within the reactor in the reaction zone is maintained so as to keep the solid particles in suspension and prevent the dispersed discharge from forming electrical arcs. Aluminum oxide is reduced to aluminum vapor which is removed with the effluent stream of gases from the reaction zone. Thereafter, the effluent is rapidly passed through a condenser where the temperature is dropped to liquefy the aluminum vapor which is then discharged in a continuous stream.