Abstract: A wide-band sigma-delta modulator is disclosed having a cascade of two moators or stages, the first stage being of third or greater order and the second being of second or greater order. Both stages utilize simple ternary quantizers to avoid linearity problems associated with the digital to analog converters in the feedback paths of the modulators and to maintain stable operation. Additional zeros are placed in the noise transfer functions of third or higher order stages by means of additional feedback loops between the output of the third integrator and the second summing junction to maximize the dynamic range. The new topology significantly enhances the dynamic range of the system while hardly affecting the circuit's sensitivity with regard to some non-idealities such as finite amplifier open-loop gains or capacitor ratio mismatches.

Abstract: A 15 mode piezoelectric sensor with mechanical amplification is provided. e sensor consists of two piezoelectric members mounted on an electronically inert, rigid substrate. The two members have an electronically inert amplification device connected between them. When acoustic energy passes through the two members, they develop an electric charge which results in the upper ends of the members moving away from each other. Since the lower ends are anchored in the substrate, this causes a shearing response in the members. The shearing is amplified by the attached amplification device, yielding a strong piezoelectric response. In detection mode, incoming acoustic waves cause a mechanical flex in the attached amplification device. The flex of the amplification device causes a shearing response in the two attached piezoelectric members. This shearing causes a generation of electric charge.

Abstract: For use in a submarine, an easily reconfigurable mast antenna system dispd within an RF transparent radome is disclosed where modularly, interchangeably designed antenna of the system are detachably attached to each other via an electronic interface connector and to a carrier backbone. RF, DC and fiber optic cables transmit signals to antennas operating in the range of 5 kHz to 18 GHz.

Abstract: A boundary layer control device for a surface which reduces turbulence by oviding forces which counteract microturbulent events occurring at the surface. The microturbulent events occur periodically with a known topography and include liftup and ejection, bursting, low-speed streak and sweep topography. The device has an array of magnet and electrode cells which are arranged to correspond with the topography arrangement of the microturbulent events. The interaction of the magnetic and electric fields within the cells generate a Lorentz force which can be directed into or out of the surface depending on the relative directions of the magnetic and electric fields. Sensors on the surface determine which cells to activate and in what direction to apply the Lorentz force to precisely counteract the microturbulent events occurring at the surface. A force directed away from the surface is used to counteract a sweep event and a force directed towards the surface counteracts a liftup event.

Abstract: A system for remotely detecting organic material in a volume, such as an layer, in situ, includes a light source, an optical receiver and a control subsystem. The light source generates a laser light beam and directs the generated laser beam at the volume. If organic material is present in the volume, the optical receiver detects fluorescent light components from the volume generated by the organic material in response to the laser light beam generated by the light source. The control subsystem controls the operations of the light source and the optical receiver.

Abstract: A valve for introducing polymer into a moving water stream prior to flowing he water stream, with the polymer therein, onto a hull surface of an underwater vehicle. The valve comprises a venturi block having therethrough a venturi passageway for flowing water therethrough, a polymer inlet tube extending through the venturi block and into the venturi passageway for introducing the polymer into the water flowing through the venturi passageway. A shut-off plunger extends through a bore in the venturi block and is axially aligned with the polymer inlet tube, the plunger being reciprocally movable in the bore between a first position in which a head portion of the plunger extends into and seals closed the polymer inlet tube, and a second position in which the head portion of the plunger is spaced from sealing engagement with said polymer inlet tube. A piston and cylinder assembly moves the plunger between the first and second positions.

Abstract: The present invention, as disclosed and taught herein, comprises apparatus nd method for an underwater turret system suitable for use on surface or underwater vessels. The turret system is housed in an underwater bay from which the turret may be deployed and operated. After operational use the turret system is retracted into the bay whereupon the bay and the system are flushed with rinse water, evacuated and dried by passing drying air through the bay. In a preferred embodiment the turret is fitted with an underwater weapon and operated to attack underwater targets.

Abstract: A large diameter load monitor sheave is provided for measuring the tension n a cable. The sheave is rotatably mounted on a cantilevered, generally vertical, fixed axle. The cantilevered axle allows the cable to be looped over the sheave without having to thread the cable between axle supports. The lower end of the axle is attached to a plate which is bolted to a mating plate on a vertical rod. Slotted holes on the axle plate allow the tilt of the sheave to be adjusted. The length of the rod can be adjusted, thus adjusting the height of the sheave. The lower end of the rod is supported by a pin connection to a base plate. A collar surrounds the upper portion of the rod just below the plate connection and the collar is affixed to an upright member projecting from a mounting support. A tensile force on the cable is translated to a tensile force between the collar and the upright member which is measured by a load cell.

Abstract: An apparatus is disclosed having a controller at each of several network es, each controller monitoring cooling fan output, ambient temperature and electrical load. Each controller includes a network interface and microcontroller for responding to requests for the values of monitored parameters. In response to such a request, the controller processes a procedure that retrieves a requested monitored parameter value and that transfers that value onto the network.

Abstract: A likelihood of detecting a reflected signal characterized by phase discontinuities and background noise is enhanced by utilizing neural networks to identify coherency intervals. The received signal is processed into a predetermined format such as a digital time series. Neural networks perform different tests over arbitrary testing intervals to determine the likelihood of a phase discontinuity occurring in any such interval. An integration time generator subsequently uses this information to define a series of contiguous coherency intervals over the duration of the received signal. These coherency intervals are then used for piece-wise processing of the received signal by parallel quadrature receivers. The outputs are combined and processed for detecting the presence of the reflected signal.

Abstract: A drag balance for measuring drag forces on a model is described which mos within a hollow region of a streamlined strut. The strut is attached to a carriage for towing the model through a medium. The drag balance has a ground frame attached inside the strut and a balance frame attached to the flat plate at the base of the strut. The ground frame and balance frame are connected by flexures which allow only a small amount of movement of the balance frame and model relative to the ground frame and strut in the towing direction. Strain gages are attached to one or more of the flexures to determine the amount of bending in the flexures and thus obtain a measure of the drag forces exerted on the model. Mounting the drag balance within the streamlined strut minimizes turbulence and allows the drag balance to be connected directly to the model at the base of the strut such that drag forces on the model are accurately determined.

Abstract: A method for controlling microturbulence in a medium flowing near a surface s disclosed. The method includes the steps of measuring the forces acting near or on the surface and using those measurements to determine the state probabilities for the microturbulent events occurring at the surface. The control method then activates selective cells in an array of cells to apply forces at the surface to counteract the microturbulent events and thus reduce turbulence. Each cell has a pair of electrodes and opposing magnetic poles such that when the control method activates a cell, the interaction of the electric field and the magnetic field at the cell creates a Lorentz force normal to the surface.

Abstract: The arrangement is directed to a roller excitation device for frictionally ngaging and turning rollers of a roller box assembly. The roller box assembly is of the type that includes a generally U-shaped housing having a partial tube which covers the open end of the housing, and a plurality of rollers captured by the housing. The rollers and partial tube define a space through which a cable is received. The arrangement being such that the rollers are adapted to roll upon engaging the cable located in the space defined by the tube and rollers. The roller excitation device includes a body portion fabricated from resilient material and sized for occupying the space defined by the tube and roller and for frictionally engaging the rollers, and means for moving the body portion over the rollers. Preferably, the body portion has an outer surface with a plurality of ribs extending outwardly along the circumference of the body portion.

Abstract: A method and apparatus are provided for suppressing flow-induced cavitation n a fluid flow. At least one acoustic transducer is coupled to the fluid flow in a region that is susceptible to the formation of cavitation bubbles. The transducer (or transducers) applies an acoustic field to the fluid flow in order to raise the cavitation threshold pressure of the fluid flow above the total local pressure including the pressure drop induced by the fluid flow and the pressure due to the acoustic field.

Abstract: A towed array handling system is provided for installation within the enled sails of future submarines. The system has a large diameter reel which provides storage for the entire array and tow cable when not deployed. The area within the enlarged sail is sufficient to allow for a dual winch and reel system for separately storing and deploying single line and/or multi line arrays. The reel applies the full tension of the streamed array as it is deployed and retrieved. When locked, the reel applies the full array streaming tension during high speed tow. The towed array is ducted from the winch to a mid ships tow point via a guide path through a ballast tank which contains only two bends. The upper sheave at the bend closest to the winch is free wheeling and the lower sheave is part of a transfer device which pulls the array from the winch during the initial phase of deployment. The guide duct is aligned with the winch to provide even spooling of the array, especially the multi line array, onto the winch.

Abstract: A target echo simulator with reverberation and ambient noise for testing an ctive sonar system. A transmit enable pulse from a sonar transmitter establishes a sequence of operations in which a target echo generator, reverberation generator and ambient noise generator produce a composite signal. The target echo generator produces a pulse modulated output pulse of a characteristic sonar frequency. The reverberation generator produces an amplitude modulating or envelope controlled output at a frequency of a carrier that is offset from the target echo carrier frequency. An ambient noise generator constantly produces ambient noise. A summing amplifier combines the generated signals to produce a composite signal for transfer to a receive connection on the active sonar system.

Abstract: An athletic garment for reducing undesirable aerodynamic drag associated h high speed sports such as bicycling or skiing includes a lightweight and skin tight garment portion for covering at least the torso portion of an athlete, and further includes a plurality of lightweight flexible ribbon fairings attached to the front, side, and aft portions of the garment. At a relatively low velocity point, the flexible ribbon fairings automatically flow rearwardly around the body and adjust to the flow of fluid with respect to the athlete to form an ideal fairing shape extending from the aft portion of the garment.

Abstract: A very low frequency augmentation system consists of a mobile target very w frequency projector (VLFP) adapted for operation as an augmentation device and installed within a torpedo shell housing. The housing is loaded within the torpedo tube of a submarine. A control and power interface is provided between the housing and the submarine to operate and monitor the augmentation device from the submarine. The housing is loaded in one of the submarine's torpedo tubes and the tube is flooded. The VLFP transmits low frequency vibrations into the surrounding seawater, acting as an augmentor.

Abstract: A method and system are provided for cooling a medium. A fluid is moved tugh the medium and bubbles are induced in the fluid as it moves through the medium. The bubble formation is induced by applying an acoustic field to the fluid as it moves through the medium. A heat sink can be thermally coupled to the fluid downstream of the medium so that heat rejected during bubble contraction and collapse is passed to the heat sink. The pressure of the fluid, i.e. the velocity of the fluid, can also controlled so that the bubbles contract and collapse in the region of the heat sink.

Abstract: A method for finding a probability density function (PDF) and its statistical moments for an arbitrary exponential function of the form g(x)=.alpha.x.sup.m e.sup.-.beta.x.spsp.n,0<x<.infin., where .alpha., .beta., n>0, m>-1 are real constants in one-dimensional distributions and g(x.sub.1,x.sub.2, . . . ,x.sub.l) in the hyperplane. Non-linear regression analyses are performed on the data distribution and a root-mean-square (RMS) is calculated and recorded for each solution set until convergence. The basis function is reconstructed from the estimates in the final solution set and a PDF is obtained. The moment generating function (MGF), which characterizes any statistical moment of the distribution, is obtained using a novel function derived by the inventors and the mean and variance are obtained in standard fashion.