Abstract: A process for the manufacture of ethanol or a like volatile organic compound by fermenting a carbohydrate with a micro-organism which will convert the carbohydrate into ethanol or a like volatile organic compound, continuously transferring a portion of the fermentation medium to a separator where ethanol or the like volatile organic compound is evaporated from the fermentation medium at a temperature which is not deleterious to the micro-organism by subjecting the fermentation medium to a reduced pressure and recycling part or all of the remaining fermentation medium to the fermenter, the rate of the circulation of fermentation medium from the fermenter to the separator and back being such that the amount of ethanol or like volatile organic compound in the fermentation medium in the fermenter is kept sufficiently low so as not to detrimentally affect the rate of fermentation, compressing the vapor issuing from the separator thereby raising its temperature, and recondensing the compressed vapor in a heat trans

Abstract: A fuel control system for a gas turbine engine for an aircraft comprising two modes of operation, a first mode in which the net thrust of the engine increases with an increase in the forward speed of the aircraft and a second mode in which the net thrust of the engine is caused to decrease with an increase in the forward speed of the aircraft, a selectively operable control device such as a valve or a valve with a least wins device being provided for selecting one of the modes of operation at a time.

Abstract: A heat input device for a heat engine comprises a combustion device which is adapted to support surface burning of a fuel and oxidant mixture and a heat exchanger which is adapted to transfer the heat from the hot surface against which the surface burning takes place to the working fluid of the engine.