Abstract: A breast imaging system is described which includes compression plates for retaining a breast during an examination. One of compression plates is formed by a polymeric membrane stretched under tension to provide a rigid but compliant retention surface which is substantially acoustically transparent for the conduct of a sonographic examination. The polymeric membrane may also be substantially radiographically transparent for the conduct of a mammographic examination. The thickness of the membrane is chosen to be a function of one-half of the wavelength of the ultrasonic frequency used for the sonographic examination so as to be substantially transparent to ultrasonic energy at that frequency.

Abstract: A breast imaging system is described which includes compression plates for retaining a breast during an examination. One of compression plates is formed by a polymeric membrane stretched under tension to provide a rigid but compliant retention surface which is substantially acoustically transparent for the conduct of a sonographic examination. The polymeric membrane may also be substantially radiographically transparent for the conduct of a mammographic examination. The thickness of the membrane is chosen to be a function of one-half of the wavelength of the ultrasonic frequency used for the sonographic examination so as to be substantially transparent to ultrasonic energy at that frequency.

Abstract: An accessory is disclosed herein for use during exercise including a layer of towel material having opposite tufted surfaces. One surface is employed for carrying a pocket having a closable end for insertably receiving personal items such as keys, money, etc. A magnetic anchor is carried on the edge marginal region of the towel midway between its opposite ends for releasably attachment to ferro-magnetic material intended to support the towel, such as an exercise stand, platform support or the like.

Abstract: A sensor is disclosed herein employing a high-sensitivity, high-resolution piezoelectric device for converting physical forces into an electrical signal. An electrical feedback circuit is utilized to cancel the capacitance of piezoelectric crystals so as to provide voltage gain with little increase in noise level. The circuit includes a unity gain amplifier outputting only pure signal gain resulting in an increase in resolution as well as in signal output.

Abstract: An elongated platform is disclosed herein for supporting a person in a chair or recliner which is adapted to rotate about a central pivot support and having wheels arranged in an arc adjacent to the opposite ends of the platform. The exposed upper surface is provided with a pair of spaced apart grooves or recesses for insertably receiving the standard rungs of the chair or recliner. Snap-lock latches releasably retain the rungs in position so that the chair or recliner and the platform constitute a unitary structure.

Abstract: An impulse hammer of a variable sensitivity type permitting the user to instantly select from at least three different full scale operational ranges which includes an elongated handle having a plastic grip at one end and a head carried at its other end normal thereto. A head extender is detachable carried on one end of the head while a force sensor terminating in an impact tip is fixedly carried on the opposite end. An electrical circuit couples to a transducer in the force sensor and communicates through the head and handle with a coaxial connector located at the end of the handle. An impedance converter is included in the circuit transforming the high impedance signal from the transducer to a low impedance output voltage. A manual selector switch changes the voltage gain of the sensor to avoid amplification of noise level.

Abstract: A calibration arrangement in combination with ammunition testing apparatus comprising an elongated test barrel and a piezoelectric transducer mounted in the barrel and having a contoured end surface in operative contact with the outer wall surface of a cartridge to be tested. The transducer converts pressure changes into electrical signals which are translated through an amplifier to a voltmeter for readout. The calibration arrangement includes a pressure tube element adapted to fit in the test barrel with one end in pressure-tight relation with the interior of an empty cartridge casing held in the test barrel and with the other end of the tube adjacent the opposite end of the test barrel. The tube is held by a retaining assembly against lengthwise movement in the test barrel. A conduit connects a source of known hydraulic pressure to the tube for introducing known calibration pressure to the interior of the cartridge casing.

Abstract: A transducer for converting pressure changes into electrical signals wherein the pressure changes act on one surface of a relatively thin wall, such as pressure changes within a tube. A piston means on one end of a transducer housing and integral therewith has a contoured end surface conforming to the other surface of the wall opposite the surface on which pressure changes act. When the pressure changes are within a tube, for example within a cartridge casing in ammunition testing, the contoured end surface is concave. Piezoelectric crystal elements rigidly positioned within the transducer are deformed when pressure is applied through the wall to the contoured end surface of the piston means, and an output electrical signal is produced proportional to the applied pressure. Installation of the transducer in a test body is facilitated by a captive retaining nut rotatably connected on the transducer housing and having external threads for connecting in the test body.