Abstract: A propulsion system for a spacecraft includes at least one electrical propulsion engine comprising at least one neutraliser; and a pressurant gas system comprising a pressurant gas which is fed directly into the at least one neutraliser.

Abstract: A propulsion system for a spacecraft includes at least one chemical propulsion engine, at least one electrical propulsion engine, and a propellant feed system that includes a propellant supply system including at least one tank to store a common propellant. The propellant supply system is configured to deliver a controlled flow of the common propellant to both the chemical propulsion engine and the electrical propulsion engine. Also disclosed is the use of a common propellant in a spacecraft and a method of providing a common propellant to an electrical and a chemical propulsion engine.

Abstract: Miniaturized hearing aid intended for a deep insertion into the auditory meatus of people who suffer from hearing problems, or "peritympanum" hearing aid, comprising a hollow body, a closure plate therefore provided with a cavity for housing the battery and with a small closing cover for said cavity operating as a movable battery holder shifting between a closed position supplying the contacts and an open position cutting the power supply of the battery, wherein the necessary thong for removing the hearing aids from the auditory meatus controls the movement of the battery holder from the closed position to the open position.

Abstract: A hearing aid having a closure plate which is removably joined through the use of screws. A battery cover is pivotable into a position where it can be easily gripped by a user's fingers so that it can aid in positioning the aid in the user's ear.

Abstract: An electroacoustic transducer is disclosed which is small in size so as to allow its use in hearing aids or like structure, but which maintains the performance characteristics of larger transducers. The transducer minimizes its cross-sectional dimensions by aligning the permanent magnet with the soft iron core instead of placing it outside the core. Adjustment of the magnetic flux is provided by a screw trimmer adjustable from the exterior of the transducer.