The dynamic mechanical properties of polymeric materials can be measured either in uniaxial compression or in flexure as a function of frequency over a wide frequency as well as temperature range, by using a piezoelectric driver to apply a displacement to a sample and a piezoelectric pickup to pick up the forces transmitted through the sample together with electrical circuitry whereby the amplitude ratio and phase angle between drive and pickup signals may be read.

A muffler of simplified construction which compensates for variations in exhaust gas pressure and flow rate in order to eliminate back pressure from the muffler has a chamber in the form of a closed loop path having a given cross-sectional area. An inlet to the chamber and an outlet from the chamber are provided for the exhaust gas. A plurality of objects, such as hollow metal balls, dimensioned to substantially encompass the cross-sectional area of the closed loop path are movable around the pa...

A dynamic loudspeaker including a dome-type diaphragm having at least one convex surface and another concave surface, contiguous with the convex surface. Specifically, the concave surface is an annular portion surrounding the convex surface.

A sealing device having an annular body, at least one annular sealing lip and an annular biasing section bonded to the lip, the biasing section being comprised of a material harder than the material of the sealing lip and serving to control deformation of the lip.

A dynamic-braking apparatus adapted to halt film movement in a microfilm viewer such that individual film frames may be easily selected. Particularly useful at high-film speeds, this braking apparatus comprises a pulley to receive braking torque and a weight which is connected to the pulley by a torsion spring. The braking force on the pulley is opposed by the inertial force of the weight, causing end displacement of the spring, resulting in its contraction and its transmission of braking torque...

A control rod drive system comprising basically a neutron absorbing control rod means defining a free floating piston, actuated by liquid sodium or other reactor coolant, a dynamic seal means and fluid valve means for moving said control rod. Said dynamic seal means constructed to prevent bypass of liquid metal, such as sodium, around the piston, and including a plurality of serially disposed skirts circumferentially arranged about the piston an sleeve and having lips directed toward the high-pr...

Tuned mass adapted to be connected to vehicle body to dampen body vibrations.

A memory stable against variation of an external supply voltage is disclosed. The memory comprises a plurality of memory cells, each of memory cells including an insulated-gate field-effect transistor having a gate coupled to a word line, a source and a drain, one of the source and drain being coupled to a digit line, and an information storage capacitor having a first electrode coupled to the other of the source and drain of the transistor and a second electrode, and means for biasing the secon...

Improvements are disclosed in a loudspeaker of the type having a speaker cone assembly which is reciprocated by a current-carrying voice coil suspended in a constant magnetic field. The constant magnetic field is generated in an annular flux gap formed by a magnetic assembly which includes a cylindrical center pole and an outer pole defining the annular flux gap therebetween. An antifriction bearing which adjoins the voice coil and slidably moves on the cylindrical center pole provides an essent...

A dynamic stop for an operator-less, remotely controlled unit carrier system consisting of a pair of stopping bars positioned between the tracks of the carrier system and mounted so that they do not interfere with the passage of the cars of the unit carrier system when not in use, but may be extended into an outward position so that they will contact stopping brackets on the underside of a car which it is desired to stop. The dynamic stop may be mounted on a reciprocating device to absorb the en...