Abstract: An interface board connector includes a plurality of individual conductive partition element seats. Each partition element seat includes four spring fingers that extend into apertures in a dielectric base plate of the interface assembly. Two adjacent spring fingers form a tweezers-like connector in one of the apertures that couples to a trace on a balun board contact post to form an impedance-matched extension of the balanced transmission line that is an integral part of the adjacent partition element seats. Each spring finger includes three distinct sections. A ramp section allows the balun board, when inserted, to push apart the two spring fingers and slide into place. The contact sections of two adjacent spring fingers form the electrical junction between the balanced transmission line traces on the balun board contact post and the section of balanced transmission line formed by the parallel spring sections of the two adjacent spring fingers.

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: The present invention provides a fixture and method for mounting a head window to a frame for use in a submarine periscope system. The fixture supports the head window during the potting of the head window to the frame. A spring-loaded clamping plate is mountable to a baseplate for relative movement therebetween. The clamping assembly has an oval recessed portion. A plurality of spaced apart feet are formed within the oval. The feet support and are bonded to the head window. Shim stock are placed between the feet to define a critical gap.

Abstract: The invention as disclosed is an underwater based electric energy production method. A cable having a piezoelectric core is attached on one end thereof to a floating buoy and on the other end thereof to an anchor. The system is deployed in the water such that the cable extends vertically through a water column. Movement of the cable due to water current generates electric power that can be harvested and stored. The floating buoy can be at or near the water's surface and the anchor can but need not rest on the sea floor.

Abstract: A digital counting circuit with multiple outputs is used to clock interlaced 16-bit data words into separate digital-to-analog converters in the correct sequence for each of eight hydrophone channels. The circuit utilizes a programmable memory to detect a synchronizing bit pattern.

Abstract: An integrated engine and generator is provided and includes a stationary non-rotating shaft. An engine block is provided that is capable of rotation about the shaft. The engine block comprises a plurality of cylinders with each cylinder including a piston translating in rectilinear motion while rotating about the shaft. A stationary generator housing and stator surrounds the block and has stator windings wound into the housing. Magnets are affixed to an outer surface of the block to rotate with the block, with the magnets separated from the housing by an air gap. The stator windings are electrically configured to match pole pairs of the magnets in order to generate electrical current upon block rotation.

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: The invention as disclosed is an autonomous magnetic measurement system for monitoring the background magnetic fields associated with power lines, electronic devices, electronic vehicles and the Earth's background magnetic field. The components of the autonomous magnetic measurement system include a series of three axis analog magnetic sensors, a fluxgate compass, and a programmable micro-controller. The micro-controller receives data from the sensor and compass and is programmed to autonomously detect magnetic signals having particular characteristics of interest.

Abstract: A slotted bifilar or quadrifilar helix antenna has a plurality of helical antenna elements. The antenna elements have an outer planar surface. A slot element is secured to an interior of the outer planar surface. The slot element extends radially inwardly to a slot element edge. At least two radially opposite slot element edges define a tapered slot. At a shorted point on the antenna, at least one radially opposite pair of slot elements are electrically shorted together. A feed point is axially offset from the shorted point along the antenna axis.

Abstract: A method for preventing accumulation of organisms on a surface exposed to a marine environment. Nano-particles are provided in a water soluble polymer. The nano-particles have a thickness of about 2 nanometers and a major surface area of about 3 microns and are treated by a quaternary ammonium salt. The treated nano-particles are mixed into the water soluble polymer material. This mixture can be applied to the exposed surface. Biofouling is prevented by the sharpness of the nano-particles, sloughing of the water soluble material, and biocidal action caused by the quaternary ammonium salt.

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: A system for three-dimensional tracking of high speed undersea projectiles may utilize a distributed field of randomly positioned passive acoustic sensors. The system measures variables related to the pressure field generated by a supercavitating projectile in flight wherein the amplitude of the pressure generated at a point in space is related to the projectile dimensions, velocity, and trajectory. The system iteratively processes data from the sensors to measure launch velocity, flight direction (trajectory), ballistic coefficient (drag), and/or maximum range.

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: An epoxy and rubber microcomposite is formed by adding a carboxy-terminated or amine-terminated rubber component having a glass transition temperature less than zero degrees centigrade to a bisphenol A based epoxy resin component; heating the mixture to 150 degrees centigrade; cooling and curing with a suitable curing agent. A phase segregation occurs between the epoxy resin component and the rubber component to form discrete, spherical rubbery domains with the epoxy compound. Because the glass transition temperature of the rubbery domains is below zero degrees centigrade; the rubbery domains act as acoustic windows within the high-modulus epoxy compound.

Abstract: An underwater data transmission system including arrays of nano-meter scaled photon emitters and sensors on an outer surface of an underwater platform. For the emitters, a laser is pulsed to correlate with data packets, providing a beam of photons at a prescribed frequency. Nano-scaled collecting lenses channel the incoming photons to photo-receptors located at a focal plane for the frequency at the base of each lens. A coating on the lenses absorbs photons at the frequency that are not aligned with the longitudinal axes of the lenses or tubes. Nano-wires connect the photo-receptors to a light intensity integrator. The integrator integrates the intensity over a surface area. The output of the integrator is fed to a signal processor to track and process the arriving digital packets.

Abstract: An apparatus and method for signal detection in which a digital sample stream is fed round robin into a plurality of buffers, which are sequentially compared with a reference signal to determine a match. A processor determines the chronological order of the samples in each bit of each buffer, and directs a bitwise comparison between the signal in each buffer with the reference to determine a match, e.g., by correlation. The apparatus and method are preferably implemented with a Field-Programmable Gate Array (FPGA). This scheme permits real time correlation of a data stream with a reference without use of shift registers, or a significant number of dedicated logic blocks.

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.