A valve comprising a housing formed with a downstream port and an upstream port, with an axially displaceable plunger biased into sealing engagement of a major flow path extending between the downstream port and the upstream port for admitting flow only in the upstream direction. The method of forming the filters includes forming at least one piezoelectric filter structure comprising a plurality of electrodes formed on a piezoelectric substrate. A method of producing a slot in a metallic workpiece having a maximum hardness value of equal to, or less than, about 65 Rc includes the step of grinding the workpiece with a bonded abrasive tool at a material removal rate in a range of between about 0. Defaulting each voltage to its least dangerous state when unprogrammed, the target interface system subsequently monitors the voltages, disabling the inputoutput connections if a problem is detected. The treated fiber contains an enhanced amount of oxygen on the surface which significantly improves the bondability of the fiber in composites. The assembly comprises an elongated outer sleeve arranged to pinch any thickness wall structure and an elongated delivery bolt arranged to be received through the outer sleeve.