A receiving apparatus which suppresses threshold-voltage changes. The method includes bonding a polymer layer to a diaphragm layer having a plurality of openings, bonding piezoelectric transducers to the diaphragm layer, filling areas between the piezoelectric transducers on the diaphragm layer with thermoset polymer, and removing the thermoset polymer from the piezoelectric transducers with a laser to expose a metal electrode on each piezoelectric transducer. At least one support bow spans the space to support the material. The overall effect is such that the abrasive distribution transversely across the jet is much more even than in a conventional blasting nozzle. The threads need not be constrained to execute on the same respective processing units during the lives of those threads\u2014though, in some embodiments, they can be so constrained.