Abstract: An impact-reinforced piezocomposite transducer array comprises a load supporting structure having a plurality of cells, each of said cells comprises a piezocomposite transducer element. The load supporting structure comprises a honeycomb structure having a plurality of multi-sided cells or the structure comprises a plurality of cylindrical cells. The piezocomposite element includes a plurality of piezoceramic rods encapsulated in a polymeric matrix to form a 1-3 composite body. The transducer array may be used as a hydrophone or a transmitter in a rugged environment such as on the hull of an icebreaker ship.

Abstract: A roller transducer assembly comprises at least one core section and each core section comprises a transducer. Oil is retained within the roller transducer assembly and in particular an oil kerf isolates each core section from an outer portion of the roller transducer assembly having a nylon roller tube which is surrounded by a urethane tire outer covering. The outer portion of the roller transducer assembly rotates about each stationary core section. A pair of the ultrasonic roller transducer assemblies are arranged to provide signals for generating an ultrasonic image of an article such as a board or a log passing between the pair of ultrasonic roller transducer assemblies.

Abstract: A multilayer capacitor includes a unitary, net-shape molded dielectric ceramic body having first and second cavities molded into at least one side to divide the ceramic body into a plurality of ceramic layers disposed generally parallel to the top. The first cavities alternate with the second cavities in the ceramic body. Each of the ceramic layers except an uppermost and a lowermost of the ceramic layers is joined at one edge to one ceramic layer adjacent thereto by a first ceramic bridge and at the same or a different edge to another ceramic layer adjacent thereto by a second ceramic bridge. The first and second cavities are filled with one or more materials to form first and second electrically conductive electrode layers, respectively, each electrode layer being bonded to the ceramic layers adjacent thereto.

Abstract: A piezoelectric acoustic sensor including stress-transferring arches to protect the elements at the lateral side surfaces. An array of parallel rod-like or blade-shaped elements is formed from a dense, poled, strongly piezoelectric or electrostrictive ceramic material. The array is encapsulated in a matrix, e.g., a polymeric matrix, to form a two-phase ceramic/polymer composite body exhibiting 1-3 or 2-2 connectivity. The upper and lower ends of the elements are exposed at upper and lower planar surfaces of the composite body to electrically contact upper and lower electrodes. A stiff portion, e.g., a face plate, extends across each of the upper and lower electroded surfaces, each extending to the edge surfaces of the composite body. A convex-shaped, stress-transferring arch is rigidly anchored to at least one edge of each stiff portion. Hinge portions of each arch at the edges of the stiff portions has a thickness of 0-10 mm.

Abstract: An actuator includes a ceramic body having a base and an array of tube-shaped or blade-pair-shaped piezoelectric or electrostrictive ceramic elements defining an enclosure and integral with the base. A first electrode contacts the inner surfaces of walls of the elements, while a second electrode contacts the wall outer surfaces. The actuator is driven for d.sub.31 mode or d.sub.15 mode vibration of the walls. The wall vibration is transmitted to a desired medium via a vibration transmission means, e.g., a compliant polymer filler material of Shore A30 to Shore D75 filling the enclosure and bonded to the walls. Alternatively, a stiff cover plate may be used to transmit the tube wall vibration to a desired medium. An acoustic sensor device is also described.

Abstract: A serpentine cross-section piezoelectric linear actuator includes a unitary, densified, rigid, monolithic piezoelectric or electrostrictive ceramic body, the body including a top, four sides generally normal to and interconnected with the top, a base generally normal to and interconnected with the sides, and two or more ceramic layers including a top ceramic layer providing the top, a bottom ceramic layer providing the bottom, and, optionally, one or more intermediate ceramic layers, the layers being disposed parallel to and superimposed over one another. Each ceramic layer except the top ceramic layer is joined at a first side to one of the ceramic layers adjacent thereto by a first ceramic bridge and each ceramic layer except the bottom ceramic layer is joined at a second side opposite the first side to another of the ceramic layers adjacent thereto by a second ceramic bridge.

Abstract: Methods for fabricating a conformable composite acoustic transducer panel including a conformable composite body having upper and lower planar faces and upper and lower thin, flexible electrodes bonded to the upper and lower faces, respectively. The composite body includes an array of individual piezoelectric or electrostrictive ceramic elements extending normal to the upper and lower faces and through the composite body from the upper face to the lower face to electrically contact the electrodes. Stiff integral face plates are bonded to the side surfaces of the elements at their upper and lower ends. Alternatively, a conformable, stiff, voided polymer matrix is bonded to the element sides over their entire length. Flexible circuit boards may be bonded to the electrodes to provide electrical contact thereto.

Abstract: A watercraft propulsion system is provided for maneuvering and positioning a dredge or weed harvesting craft in shallow waterways and includes a pair of booms positioned adjacent the port and starboard sides of the craft. Submersible and reversible motors are provided at the remote end of each pivotally mounted boom for independently driving wheels provided with a plurality of circumferentially spaced blades. The wheels include an enclosed buoyancy chamber to offset the weight of the wheels and the booms, and the blades are removable and may be provided in different configurations to accommodate different operating conditions. A pumping unit including a cutterhead is provided whereby the watercraft can perform dredging or aquatic weed harvesting operations.

Abstract: A conformable composite acoustic transducer panel including a conformable composite body having upper and lower planar faces and upper and lower thin, flexible electrodes bonded to the upper and lower faces, respectively. The composite body includes an array of individual piezoelectric or electrostrictive ceramic elements extending normal to the upper and lower faces and through the composite body from the upper face to the lower face to electrically contact the electrodes. Stiff integral face plates are bonded to the side surfaces of the elements at their upper and lower ends. Alternatively, a conformable, stiff, voided polymer matrix is bonded to the element sides over their entire length. Flexible circuit boards may be bonded to the electrodes to provide electrical contact thereto. Methods for fabricating the transducer panel are also disclosed.

Abstract: A flextensional cover plate for redirecting the vibrational displacement of terminal ends of at least one pair of piezoelectric or electrostrictive ceramic bender elements vibrating toward and away from each other. The flextensional cover plate includes at least one flexible pleat configured to be bondable to terminal ends of the bender elements such that the bender element vibrational displacement is converted to vibrational displacement of said cover plate in a direction normal to said element vibrational displacement. The preferred flextensional cover plate is configured such that the amplitude of the cover plate vibrational displacement is greater than that of the bender element vibrational displacement.

Abstract: A method and apparatus for cutting aquatic vegetation is provided which substantially reduces the tendency to wrap or clog conventional cutterheads. A cutterhead of the present invention includes a plurality of radially oriented rotatable cutting members which cooperate with stationary cutting teeth to tear weeds and other aquatic vegetation. The rotatable cutting members are preferably spirally mounted along a smooth rotatable drum to inhibit draping of the vegetation during cutting. Recessed cutting teeth are located at the ends of the drum to further inhibit aquatic vegetation from passing through gaps between the drum and the cutterhead shroud. The shroud directs the cut vegetation to a submersible pump so that it may be pumped to a remote site.

Abstract: A pump for handling abrasive materials includes a housing having two chambers. A shaft mounts a high pressure impeller and a high volume impeller in respective chambers of the housing, each chamber having a separate and opposite inlet. A channel is provided to divert a portion of the flow generated by the high pressure impeller to a purge ring adjacent the primary inlet corresponding to the high volume impeller. The purge ring directs a flow of relatively abrasive-free liquid toward the inlet to reduce wear on the housing and high-volume impeller. Another part of the flow from the high pressure impeller is diverted through the housing to isolate portions of the housing and the high volume impeller from the abrasive material laden intake through the primary inlet.

Abstract: Apparatus for continuously and selectively plating a stripe of metal onto a continuously moving metal strip, said apparatus comprising a hollow, rotatably mounted plating wheel having a peripheral slot extending around the circumfery thereof, said slot communicating with the interior of said wheel, and distribution means fixedly mounted within said wheel, said distribution means comprising an electrolysis chamber and a suction chamber, means for feeding an electrolyte solution to said electrolysis chamber, and means for applying negative pressure to the suction chamber, whereby when the metal strip to be plated is maintained in driving engagement with the periphery of said wheel, said strip covers said slot, said electrolysis chamber having anode means associated therewith, and said strip being connected as a cathode, whereby electrolyte passing through said electrolysis chamber is electroplated on the exposed inner surface of the strip, with excess electrolyte continuously being drawn off through said suctio