Abstract: A lightweight direct methanol fuel cell unit (20) comprising a fuel cell stack (24) enclosed within a housing (22). In one embodiment the fuel cell stack includes a plurality of polymer electrolyte membrane electrode assemblies (52) stacked alternatingly with a plurality of bipolar plates (48). Each bipolar plate includes a cathode flow field (78) defined by a porous cathode flow field structure (56) and an anode flow field (62) defined by an upper plate (58) and a lower plate (60) separated from one another by a plurality of spacers (64). The anode flow fields are manifolded with one another via manifold embossments (118, 120) that are hermetically sealed with one another with a gasket (126). The fuel cell stack and housing are shaped so as to form four manifold regions (36) in the spaces between the fuel cell stack and housing.

Abstract: A radial piezoelectric motor comprises a housing, a motor shaft rotatably mounted in the housing and a plurality of piezoelectric actuators inside the housing radially disposed about the axis of the motor shaft. The motor also includes circuitry for applying a voltage to the piezoelectric actuators to expand the actuators repeatedly and in succession and apparatus responsive to the repeated and successive expanding of the actuators for rotating the motor shaft.

Abstract: A piezoelectric fan is comprised of two counter-oscillating flexible blades that are driven at resonance by a bimorph comprised of two piezoceramic bending elements. The fan is provided within the flow duct of a circulating gas laser. The operation of the piezoelectric fan serves to create a flow of a laser gas medium in a desired direction through the flow duct, thereby replenishing the gas medium between a pair of laser electrodes. The fan has no wearing elements, such as bearings, and requires no bearing lubricant resulting in the elimination of lubricant hydrocarbon and bearing particulate contamination of the laser gas medium.