Abstract: A piezoceramic vibration control device in which stiffness is established by a capacitor in shunt with piezoceramic element of the device. The device can be formed of a stack of piezoceramic elements bonded to one another and precompressed by a spring. A control system is arranged to tune the natural frequency of the vibration control device to a disturbance frequency or s primary structural response frequency by varying the capacitance of the capacitor.

Abstract: Self sensing actuator system using a piezoelectric actuator device allows the device to perform both as an actuator and sensor. The sensor functions can be either measurements of stress or measurements of strain. The actuator can be used as a force generator or positioning device, both in open and closed loop configurations, and is useful for purposes ranging from dynamic damping to shape control (i.e., shaping or controlling deformation of a body).

Abstract: A quick-donning protective hood assembly for respiratory protection from smoke and noxious gases. The assembly consists of a clear "TEFLON" film hood (12) having a scrubber canister (20) and an exhaust valve (42) supported thereon. A neck seal (14) is connected to the lower marginal edge of the hood. A springlike hoop (16) is connected to the lower marginal edge of the hood. A bib (18) is carried by the springlike hoop and supports an oxygen generator (22) which is interconnected with the scrubber canister by an oxygen supply line (24). Waist straps (54) extend from the sides of the bib and may be adjusted to secure the bib about the wearer. The assembly can be stored in a cylindrical storage container with the hoop being collapsed. When the assembly is withdrawn from the storage container, a lanyard (62) will initiate the operation of the chemical oxygen generator.

Abstract: A closed circuit breathing apparatus such as that worn by personnel in irrespirable atmospheres. The apparatus is mounted on a backframe and housing 14 and is adapted to be interconnected with a face mask 12. The apparatus includes exhalation and inhalation passageways 18, 20, a source of breathing gas 50 which is released into the breathing apparatus at a constant volumetric flow rate, a carbon dioxide scrubber 38 and an ejector pump 40 which is driven by the source of pressurized breathing gas and which causes the pressurized breathing gas and exhaled air to be driven through the carbon dioxide scrubber at a relatively constant flow rate. The apparatus further includes a spring biased inhalation gas accumulator or counterlung 46 on the downstream side of the carbon dioxide scrubber, which counterlung is in communication with the inhalation passageway.