Abstract: Cubelets are made from a piezoelectrically active ceramic material having holes therein which may be cross-cored. The holes are selectively filled with a liquid curable resin, such as an epoxy. The cubelets may also be formed from bonded or sintered "half-shapes" containing half cores, wherein a face bisects one hole or an array of holes or cross-cored holes to form one or an array of semicircular grooves or crossed semicircular grooves. The cubelets, whether filled with resin or having unfilled internal volume, are arranged in a precision array within the snug-fitting cavities of a lattice, whereby the holes are sealed off, to form a cubelet/lattice assembly which is then electroded and poled in an electric field and encapsulated in polymer to form a part of a hydrophone assembly, for example.

Abstract: The instant invention involves a process for use in preparing tapes or rovings, which are formed from a thermoplastic material used to impregnate longitudinally extended bundles of carbon fibers. The process involves the steps of (a) gas spreading a tow of carbon fibers; (b) feeding the spread tow into a crosshead die; (c) impregnating the tow in the die with a thermoplastic polymer; (d) withdrawing the impregnated tow from the die; and (e) gas cooling the impregnated tow with a jet of air.The crosshead die useful in the instant invention includes a horizontally extended, carbon fiber bundle inlet channel, means for providing melted polymer under pressure to the die, means for dividing the polymeric material flowing into the die into an upper flow channel and a lower flow channel disposed above and below the moving carbon fiber bundle, means for applying the thermoplastic material from both the upper and lower channels to the fiber bundle, and means for withdrawing the resulting tape from the die.