Abstract: An engine system using refrigerant fluid is capable of utilizing the heat produced by an external high-efficiency hydrocarbon fuel combustion process. The heat from that process is utilized to transform the refrigerant fluid from a liquid state to a gaseous state in a cycle which includes extracting work from the fluid in the gaseous state in a high-compression-ratio piston engine. The cycle further includes transforming the fluid in the gaseous state back to the liquid state in a condenser, and then feeding that fluid under pressure to a heating chamber where the combustion process heat again returns it to the gaseous state at high pressure and temperature. The engine system has a higher efficiency than hydrocarbon fuel combustion engines, and has particular application to use in automobiles. One preferred refrigerant fluid for this engine system is 2,2,Dichloro-1,1,1,Trifluoro-Ethane.

Abstract: A hydrophone (16) having a short-baseline array of transducers (12A, 12B, and 12C) as well as a long-baseline array of transducers (14A, 14B, and 14C) includes switches 30A, 30B, and 30C) for selectively connecting the outputs of the arrays to a cable (18) that carries the signals to processing circuitry (20) aboard an ocean-going vessel (24). The switches (30A, 30B and 30C) change state in accordance with the output of a narrow-band filter (42), which indicates whether the received signal is of a predetermined frequency and thus is likely to have been produced by an intended source. Due to the delay inherent in the narrow-band filter 42, the processing circuitry (20) thus processes the response of the long-baseline array to the first part of a beacon pulse and the response of the short-baseline array to the second part of the beacon pulse.