Abstract: A composite relatively flexible resilient flap member has a movable flap and is formed of composite reinforcing fibers such as nylon, carbon or polyester impregnated with elastomeric flexible fuel resistant material. A rigid sheet member formed of composite material comprising reinforcing fibers such as glass, carbon, polyester and nylon and epoxy stiffens the flap. The flap overlies a fuel fill opening in a support plate with a major portion of the flap member fixedly overlying the plate. The flap is offset in an opening of a mounting plate secured to the support plate. The stiffened flap member is preformed with a bend to form a resilient biased hinge when flattened, the hinge being spaced from the fuel fill opening. The flap member and rigid member have low inertia to assist in rapid closure. Other embodiments are disclosed. A fuel cell tank breather vent has a tube with a male valve slug having an elongated shank.

Abstract: The light selected by a selection circuit 3 at a light emitting side and emitted from a light emitting element 1 such as a LED is converted to a specifically modulated light by an oscillation circuit 11. The light received by a light receiving element 2 such as a phototransistor at the receiving side is amplified by an amplifier circuit 6, and a detection circuit 12 detects whether a specifically modulated light is received. The H/L detection circuit 13 determines the presence/absence of a light interruption to produce a signal of either H (high level) or L (low level). Also, the signal from the oscillator 11 of the emission side is received by the receiving side and compared with the received signal to determine whether the same signal as emitted from the emitting element has been actually received.

Abstract: A wafer of lithium niobate metallized on both major surfaces is bonded to a magnesium aluminate spinel bulk acoustic delay line. The lithium niobate layer is divided into two separate electrically and mechanically isolated transducers using ion beam milling. The bulk acoustic delay line has a surface arranged to reflect a propagating acoustic wave generated by one of the divided transducers to the other of the transducers, the one transducer serving as an input and the other as an output. The acoustic delay line is suitable for broad band operation at microwave frequencies with at least 50 db isolation between the two ports.