Abstract: A method for making a piezoelectric composite transducer is disclosed. A block of piezoelectric material having a common base and a plurality of uniform-length rods is utilized. An electric conductor is positioned to extend through a side region of the block. Spaces between the rods are filled up to a first surface region with a viscoelastic material. The common base of the block is removed forming a second surface region. Electrodes are deposited at the first surface region to be in contact with the rods and in electrical contact with the electric conductors. A ground electrode is deposited at the second surface region to be in contact with the rods. The resulting piezoelectric composite transducer can be heated and shaped to conform to complex curves.

Abstract: A method and system is provided that improves the maneuverability of a marine vehicle having a lateral tunnel thruster. When the marine vehicle moves at a forward speed through water, a water flow having a fluid velocity moves through the thruster. The thruster's propeller is turned at a substantially constant rate of rotation and the fluid velocity in the tunnel is measured. The pitch angle of the propeller is adjusted based on the measured fluid velocity.

Abstract: A method for characterizing ocean bottom properties in real-time by explong the multipath structure of reverberation to extract values for bottom loss and the bottom scattering coefficient. The bottom parameters are extracted from a measured reverberation energy envelope generated from the reverberation returns of one or more pings from a sonar system. The measured reverberation envelope is compared to a reference reverberation model to identify a period of time in which the measured reverberation energy envelope exhibits properties that allow the extraction of bottom parameters. The bottom parameters are then extracted by direct comparison of the measured reverberation to the reference reverberation model within the time period or by iteratively changing the value of bottom loss or bottom scatter coefficient and recalculating the reference reverberation for the identified time period until the reference reverberation matches the representative reverberation.