Abstract: The present noise reducing apparatus includes resonators which have a small and variable volume as well as a high admittance. For this purpose the resonators constitute vibrating systems having at least one volume wherein the pressure is reduced below atmospheric pressure to provide a reduced volume stiffness. The volume is confined by wall elements having a very small or a negative spring rate under reduced pressure inside said volume.

Abstract: A container, especially a flat container suitable for confining high internal pressures includes inner membranes secured to lateral side frame members. The inner membranes have inwardly facing convex surfaces and bear against outer walls through hard foam filler material located in the spaces between the inner membranes and the outer walls. The membranes and the walls are manufactured by filament winding techniques.

Abstract: An ion prime mover or engine includes an ionization chamber closed up by a plasma boundary anchor. A field winding surrounds the ionization chamber for producing a high frequency electromagnetic alternating field. Such field ionizes a gas in the ionization chamber. The ion engine further includes an anode-cathode path for producing an electrostatic field, wherein the ionized gas is accelerated out of the ionization chamber through the apertures in the plasma boundary anchor and in the cathode. The high frequency electromagnetic alternating field is arranged in such a manner that this field is substantially undisturbed in the area of the plasma boundary anchor and that the field lines extend substantially perpendicularly to the surface of the plasma boundary anchor facing the ionization chamber.

Abstract: A piezoelectric acceleration transducer has a piezoelectric element with a plane surface arranged in contact with a mass. The mass and the piezoelectric element are held in fixed relationship to each other by a support structure arranged in such a manner that inertia forces effective on said mass are directed to be effective perpendicularly on the plane surface of the piezoelectric element. A bearing point or line is provided between the mass and the support structure in such a position that the directional sensitivity of the transducer may be determined by said position.

Abstract: A constant current source is provided by a circuit of two metal oxide semiconductor field effect transistors (MOSFET) of the enhancement type having opposite conductivities. One transistor constitutes an input transistor. The other transistor is the output transistor. The drain terminals are connected to the respective polarities of an operating voltage source. The gate terminal of the input transistor is connected to a control voltage source. The source terminals are interconnected and grounded through a resistor. The constant current is available at the drain electrode of the output transistor. If it is desired to produce constant output currents of alternating directions, two such circuits may be interconnected in mirror symmetrical fashion.

Abstract: A telescopically adjustable surgical instrument for a distraction apparatus used in performing an elongation osteotomy comprises a rigid support rail having a guide chamber or guide recess and a rigid extension rail axially slidable in said recess. The extension rail has hinged bone connecting plates by means of which the extension rail may be attached to the distal part of a bone. An extension drive mechanism may be releasably connected to the two rails. The instrument is completely implantable. After the distraction, the position of the extension rail is fixed and the drive mechanism may be easily removed.

Abstract: An elastomeric damping arrangement is constructed to provide a highly efficient damping of the vibrations of a vibration prone member, such as an airfoil, especially a helicopter rotor blade. The damping arrangement is applied directly on or to the vibration prone structural member in the region of dynamic deformation, as an integral component part of the structural member. At least one damping layer is covered by a protecting layer which merges smoothly into the surface of the vibration prone member. The damping layer is made of a viscoelastic material having a high internal damping action. The protecting or cover layer is made of high strength material having a high rigidity in the direction of the occurring damping force.

Abstract: The present accelerometer uses the total light reflection of a prism for suring an acceleration force by disturbing such total reflection in accordance with the displacement or deflection of a body located close to a boundary surface of said prism, and responsive to the movement of an inertia mass which in turn responds to the acceleration force. The reflected light is measured by a photosensitive device and the resulting electrical signal is a direct measure for the size of the acceleration force. In order to make the measuring of the acceleration force independent of variations in the intensity of the light emitted by a light source used as part of the accelerometer, a reference signal may also be produced to form a quotient of the measured signal and the reference signal.

Abstract: The present apparatus controls the position of the brake flap or air brake of an aircraft. The air brake is operated by a power amplifier including a pressure cylinder and a piston. The piston is mechanically coupled to the brake flap or air brake in such a manner that the displacement of the brake flap is about proportional to the brake flap angle. The pressure in the cylinder is controlled in response to or as a function of the brake flap angle so that the flap is positioned at the angle required for the particular braking action, whereby the force caused by the dynamic or impact pressure is maintained in equilibrium with the force exerted by the pressure piston cylinder arrangement.

Abstract: An ejector for the transport container of a missile is used in a missile launcher. The missiles are launched from the container which is then ejected by an ejector mechanism from the launcher proper. The ejector comprises a pair of axially spaced pivoted levers and first spring means for imparting an ejecting movement to said levers and second spring means for returning the levers to a ready position to receive another missile in its container.