Abstract: A dynamic acoustic impedance matching device for an acoustic signal transmitted or received in a medium by a transducer includes a particle flow in an acoustic signal path of the transducer. The particle flow has an acoustic impedance between an acoustic impedance of the transducer and an acoustic impedance of the medium.

Abstract: A method and apparatus for non-destructively determining features in a planer specimen includes providing a heat impulse to the specimen, detecting temperatures in the specimen at a plurality of locations, and imaging the specimen from the detected temperatures. A laser can be used to provide a single or a plurality of heat impulses to the specimen. Temperatures in the specimen can be detected utilizing a contact sensor array or a remote infrared detector. These sensors are joined to a data processing device to image the specimen utilizing the detected temperatures.

Abstract: A well conductor strain monitoring system is provided which includes a plurality of fiber optic Bragg grating sensors written onto a single optical fiber. Cable strands are wound around the optical fiber to form an armored cable protecting the fiber. The armored cable is further integrated into a strength cable to provide robustness. This strength cable is then wrapped around the conductor under tension and anchored at both ends. The cable is wound at a prescribed angle so as to have multiple wraps around the conductor. Once tensioned, the cable remains stationary against the conductor and holds a position. The strain gages are spaced along the optical fiber, such that the strain gages are oriented 90 degrees apart when the cable is wrapped about the conductor. This orientation supports the estimation of bending in any direction.

Abstract: The invention is a method directed towards measuring differences in sounds, temperatures and pressures detected within a marine mammal, then analyzing the data to better understand the activities and behavior of the marine mammal. Wherein a buoyant capsule having a hydrophone, a temperature sensor, a pressure sensor, a memory chip, a radio frequency (RF) generator (or other means to enable its detection), software and a battery enclosed within a shell is disposed into a body of water. After a marine mammal ingests the capsule, the capsule is activated after which pressure data and sound data is detected, including sonar transmitted by a monitoring ship. The data is saved on the memory chip for recovery.

Abstract: A device operable as a transducer is provided for use in which the device is mountable on a tow cable which in operation extends underwater substantially throughout the length thereof. The device comprises a head mass encompassing the tow cable wherein the head mass reacts to a wave-like strumming configuration about an axis of the tow cable thereby causing the tow cable to be displaced in one direction, along the axis and then in an opposite direction such that a low frequency continuous sound wave radiates from the head mass.

Abstract: A method is taught to extract more information about the motion of an acoustic wave emitter moving relative to a line array of hydrophones that are part of a sonar system by determining the variation in Doppler shift across the entire line array of hydrophones together with the a range measurement of the emitter to calculate the emitter's velocity.

Abstract: A forward and aft open-ended, towed underwater acoustic source having a hollow with a plurality of wires disposed in parallel across one or both of the end openings. In operation, water flows around the wires and proceeds through the hollow body, exiting the aft open end of the body. The tensioned wires are situated normal to the direction of flow in order to cause production of Strouhal vibration frequencies due to the vortex shedding action of the water flow behind the wires. The source transmits broadband acoustic energy without requiring heavy transducers.

Abstract: An active sonar system for detecting objects in water includes: a transmitter capable of generating and transmitting an acoustic signal having acoustic pressure pulses; a cable extending from the transmitter into the water, the cable including a hose filled with hydraulic fluid receiving the acoustic pressure pulses from the transmitter, a water blocking layer and cable wire; and a winch assembly including a winch drum for deploying and retrieving the cable into and out of water. A flattened hydraulic chamber section of the hose is secured within the winch drum with acoustic transducers mounted on either side of the flattened chamber section, so that the acoustic transducers act as pistons to generate acoustic pressure onto the hydraulic fluid for generation along a length of the cable.

Abstract: A coaxial transducer that uses lead zirconate titanate ceramic or other suitable material as an isolator between the conductors in a coaxial cable to transmit acoustic power at useful levels. The lead zirconate titanate ceramic is diced into thin disks and placed in between spacers made of much stronger insulating material. The coaxial cable is then integrated into a conventional double-armored steel tow cable with a typical diameter of 1?. This provides substantial longitudinal strength and provides crushing resistance to the lead zirconate titanate ceramic when the cable is being deployed or retrieved over a sheave under tension.

Abstract: A coaxial transducer that uses lead zirconate titanate ceramic or other suitable material as an isolator between the conductors in a coaxial cable to transmit acoustic power at useful levels. The lead zirconate titanate ceramic is diced into thin disks and placed in between spacers made of much stronger insulating material. The coaxial cable is then integrated into a conventional double-armored steel tow cable with a typical diameter of 1?. This provides substantial longitudinal strength and provides crushing resistance to the lead zirconate titanate ceramic when the cable is being deployed or retrieved over a sheave under tension.

Abstract: A system and method for generating an underwater acoustic waveguide suitable for guiding acoustic energy between a source and a receiver to enable underwater communications. Electrolysis of water by electrically powered terminals continuously creates a bubble field having a volume fraction of less than 0.01% gas. The bubble field has a lower sound speed than the surrounding water, resulting in the bubble field acting as a waveguide to transmit sound over the length of the bubble field. By maintaining small bubble radii, the bubble field can be stable for long periods of time. By keeping the volume fraction and bubble radii small, the power requirements for the terminals are minimized.

Abstract: An acoustic source for use in a saltwater environment includes a transducer for projecting acoustic energy. The transducer is positioned within a semi-permeable membrane. The volume around the transducer within the membrane is filled with water having a lower concentration of a solute such as salt. When positioned in the saltwater environment, an osmotic pressure is created within the membrane. This osmotic pressure acts to suppress cavitation such as that which could be generated by the transducer. In further embodiments a support structure is used to support the membrane and the transducer could be an array of transducers.

Abstract: A device for deflecting acoustic waves for an object in a liquid environment includes a heating grid and a cooling grid. The heating grid is positioned about the object and increases the temperature in the liquid environment. The cooling grid is positioned about the object to cool the liquid environment outside the heating grid. Jointly, these grids establish a temperature gradient in the liquid environment that is capable of bending acoustic waves in the environment. The cooling grid and heating grid can be established through mechanical, electrical or chemical methods. Alternatively, the required temperature gradient can be established by a heating grid alone in a moving vehicle wherein the heating grid is continuously in contact with undisturbed water at the ambient temperature.

Abstract: Systems and methods are provided for determining information about particle geometry are provided. As such, an ultrasonic transducer acts as both a transmitter and a receiver. The transducer insonifies a particle and scattered waves are then received by the transducer—now acting as a receiver. A small flat target moving relative to a stationary receiver will lead to the same radiated field as waves propagating through an equivalent moving aperture. Based on the Doppler distribution of the scattered or radiated waves resulting from relative motion between the particles and a receiver, the acoustic pressure field in the plane of the equivalent two-dimensional aperture can be inferred. The equivalent aperture geometry can be obtained from the inferred field. Hence, the particle geometry can be determined.

Abstract: An acoustically-focused optical lens is provided that uses acoustic transducers arranged in diametrically-opposed pairs around an exterior surface of a cylindrical tube in order to concentrate (heavier-than-water metallic) particles suspended in water within the interior of the tube to be along a central axis of the tube. The transducers are activated in accordance with higher order (and odd order) Bessel functions to create an asymmetric mode in order to create the central axis node. Distortions in the optical lens can be further reduced by arranging two or more of the tubes in series with their central axes aligned.

Abstract: The invention as disclosed is a system for real time detection of tsunami waves. A tsunami is considered a “shallow water wave”, having a large wavelength compared to the ocean depth. A tsunami can have wavelengths ranging from 100 to 500 km, and amplitudes up to 60 cm (i.e., a pressure signal of up to 1 psi). At least one telecommunications grade optical fiber cable fitted with repeaters spanning the length of an ocean, a laser and a signal processor are used to measure pressure signals over spatial cells as small as 0.5 meters in width based on Rayleigh scattering effects and employing optical time delay reflectometry. The tsunami pressure signals are extracted from the pressure signals generated by wind-generated water waves (having much shorter wavelengths) through signal processing to distinguish between the substantial differences in wavelength, period and propagation speed.

Abstract: A system and method are provided for launching and recovering an unmanned, water-born vehicle (UWBV) from a mother ship. The UWBV mimics the behavior of dolphins and is positioned ahead of the ship in preparation for bow riding. The UWBV uses a guidance system to position and keep in the bow wave. A high-frequency (HF) sonar transceiver array aboard the ship computes and sends course corrections to maintain the UWBV within the bow wave. The frequency range of the HF array can be 100 kHz or higher due to the short distance between the ship and the UWBV. Accordingly, the HF array can have a small aperture allowing for accurate bearing resolution. Course corrections can be sent on a near-continuous basis such that changes in thrust and rudder angle can be minimized to allow for accurate control of the UWBV.

Abstract: A transducer with a closed heat pipe is provided with a hot surface and a cold surface. The hot surface is in contact with the transducer interior and the cold surface is in contact with a cooler contact area. A fluid is used in the pipe which boils at the temperature of the hot surface and condenses at the temperature of the cold surface. A wick inside the heat pipe facilities the return by capillary action of the condensed fluid to the hot end. The heat pipe can be evacuated to adjust the boiling temperature of the fluid. A variant involves drilling additional holes into ceramic rings and inserting heat pipes. Increasing the heat pipe length into the tail mass and the piston increases the cool region for the fluid to condense; thereby improving the performance of the transducer.

Abstract: Systems and methods for automatically applying fairings to a cable as the cable is deployed from a winch are provided. Each fairing has two halves, with each half having a recess, or groove, to accommodate the cable. Like halves are connected together and the two halves are stored on separate spools. Counter-rotating wheels adjacent to and on opposite sides of the cable serve to feed the fairing halves from the spools to the cable as the cable is deployed. As the fairing halves approach the cable, magnets in the fairing halves are attract each other and bring the two halves together around the cable and firmly hold the two halves together. When the cable is retrieved, guides align the fairings such that a wedge can pry the two halves apart. The halves can be picked up by the wheels and fed back onto the spools.

Abstract: A handling system with an improved fairlead is provided for protecting a tow cable wherein the cable breaking strength exceeds the system-rated tension load; the fairlead being positioned collinearly between the system bellmouth and winch. A guide slot passes through the fairlead positioning the cable higher than the winch release point and bellmouth entry point, maintaining the cable down-slope as the cable exits the fairlead. The slot has a hemispherical portion tapering inward to a groove extending downward. Near the groove bottom, at the fairlead end nearest the bellmouth, is a cutting device. Under tension, the cable rides in the hemispherical portion of the groove. If tension suddenly increases from a snag, the resulting force drives the cable down into the groove where the cable is cut by the device, separating before the force damages the system. The constrained cable end is securely held in place by the taper.