Abstract: The disclosure is directed to a circuit for producing electrical discharges in response to trigger signals, and a form of the disclosure is directed to an apparatus, which includes such a circuit, for determining the transit time of acoustic energy travel between a transmitter location and a receiver location.

Abstract: The sonar transducer includes a metal core about which is situated a cylindrical piezoelectric ceramic ring element with paper interposed therebetween. In order to improve resistance to fracture resulting from mechanical shock, in one embodiment, the core is reduced in diameter, such that a potting compound can be situated between the paper and the ring. In a second embodiment, the ring element is divided into two individual, axially aligned cylindrical ring subelements with a gasket interposed therebetween.

Abstract: A method and apparatus for compensating sensitivity fluctuations in signals received from respective groups of hydrophones for the purpose of subsequent signal processing, the groups being arranged in a predetermined sequence (0, 1, 2, . . . i) to form a transducer arrangement, wherein the received signals are influenced by the sensitivity of the hydrophones and/or the gain of preamplifiers connected to the outputs of the hydrophones. The energy value (W.sub.i) for the received signals of each group of hydrophones is determined and a median energy curve (W.sub.m (.theta.)) is derived from the energy values (W.sub.i) as a function of the sequence of the groups of hydrophones. A correction value is formed for the signals received from each group of hydrophones from a comparison of the respective energy value (W.sub.i) with the energy curve (W.sub.m (.theta.)) and the received signals are corrected with the correction value.

Abstract: A method and apparatus for nuclear logging, and in particular, neutron porosity logging is presented. In accordance with the present invention, a novel programmable gain amplifier circuit and a novel peak detector circuit are used in conjunction with other electronic circuitry to provide borehole formation logs in a nuclear logging tool.

Abstract: A piezoelectrically-driven, resonant-pipe projector has formed therein vents to broaden the response of certain cavities resonances and to increase the response between these resonances. The projector exhibits a relatively high electroacoustical efficiency, is capable of medium to high power output over the operating band, and is not depth dependent or depth limited.

Abstract: An aircraft windshield system which employs a relatively thin outer windshield member in combination with a thicker ballistic protection inner windshield member and a plurality of electively disposable specific threat protecting panel members is disclosed. The specific threat protecting panel members are arranged for storage during normal peacetime use of the aircraft, and for rapid and selective deployment into protecting positions when elected by the aircrew or as determined by a mission knowledgeable computer apparatus or other means. The results of studies indicating the desirability of multiple-panel windshield structures from both cost and performance viewpoints are also disclosed. The disclosed windshield system is especially applicable to future military aircraft such as the Advanced Tactical Fighter (ATF) and Advanced Tactical Bomber, and may also be retrofitted to existing aircraft for upgrading purposes.