Abstract: A portable apparatus and a method for inserting digitized previously recorded or fabricated radio frequency (RF) pulse descriptor word (PDW) data files into an electronic surveillance (ES) system to realistically simulate a complex RF environment. The apparatus includes a personal computer and an electronics unit configured for easy integration into an ES system between the receiver and pulse processor. PDW data files are created on the personal computer and transmitted to the electronics unit as supplied PDW data. In the primary embodiment, real RF pulse data from the receiver is halted in the electronics unit and supplied PDW data and data from the receiver unrelated to PDW data, is passed in a continuous stream to the pulse processor. In a secondary embodiment, an upgrade in the electronics unit multiplexes both real RF pulse data and supplied PDW data for transmission to the pulse processor.

Abstract: A muzzle break for a gun comprising a baffle, a series of slots in the housing of the muzzle break in which the slots exhaust gas of a pressure wave deflected by the baffle during firing of the gun. A membrane seals the slots for underwater use and is separable by the deflected exhaust gas. Another membrane seals a sabot separation chamber of the muzzle break adjacent to the baffle and in a projectile path from the baffle. The membrane for the separation chamber is detachable by a projectile fired from the gun.

Abstract: An igniter's housing is bored continuously there through to define, in succession, several bore regions. A firing pin, slidingly fit in the first bore region, terminates in a tip that protrudes into a primer-filled second bore region when the firing pin is fully seated in the first bore region. An air-filled third bore region follows the second bore region. An open-ended cup is fitted substantially in and sealed to the fourth bore region with the cup's closed end being structurally weakened at a portion thereof. A bored out slug of pyrotechnic material is fitted in the cup.

Abstract: An apparatus for attachment to a commercially available cleaning wand for maneuvering the wand inside a storage tank. Two arms each have an end pivotally connected to a handle and another end pivotally connected to the wand to form a four bar linkage. A gimbal arrangement is supported above a base, which is placed over an opening in the tank, and one of the arms is coupled to the gimbal arrangement to allow movement about three mutually perpendicular axes for directing the wand to various orientations within the tank.

Abstract: The present invention is directed to a system and a method for analyzing and identifying an unknown sample using ion mobility spectrometry. The method pulses an ion gate using a temporally spaced pattern of ion admitting periods and ion repelling periods to achieve an admission duty cycle of about 50% of the total scan time. Ions passing through the drift tube strike an ion detector, generating a time dependent mobility spectrum. A combination of wavelet decomposition and statistical evaluators are used on the mobility spectrum to produce a distinct signature associated with the sample. Signatures are also generated for a number of known agents, and the known agent signatures are used to program a neural network. The sample signature is then compared to the signatures for the known agents using a fuzzy decision maker.

Abstract: A method for measuring the complex frequency-dependent dilatational and shear wavespeeds of a slab of material subjected to insonification. Transfer functions that are obtained by insonifying the material at different angles. Once this is accomplished, the transfer functions are manipulated with an inverse method to yield closed form values of dilatational and shear wavespeeds at any test frequency. The wavespeeds can be combined to determine complex Lamé constants, complex Young's modulus, complex shear modulus, and complex Poisson's ratio.

Abstract: A steering system is provided for a hydrodynamically shaped vehicle having a nose end, a tail end, and forward propulsion. The steering system includes an internal supply of drag-reducing medium, at least one ejector ring positioned adjacent a nose end of the vehicle, and a plurality of ejector sections formed in the at least one ejector ring. Each ejector section includes an opening arrangement for ejecting drag-reducing medium to an external surface of the vehicle. A control unit selectively supplies drag-reducing medium to at least one of the plurality of ejector sections. The drag-reducing medium ejected from selected ejector sections causes a reduced-drag surface on said vehicle body and an increased speed thereof relative to a remainder of the vehicle body and thereby imparting a directional motion to the vehicle in the form of pitch and/or yaw.

Abstract: A dual channel downconverter that includes a two-channel heterodyne receiver architecture for downconverting two frequency-agile, pulsed RF signals to identical fixed IF signals without the use of a tunable local oscillator. This accomplishes downconversion while preserving, in the IF output signals, any amplitude modulations present in the RF signals. The device also preserves phase difference changes present in the RF signals while rejecting the phase modulations common to those input signals. The present device facilitates complex response measurements of pulsed two-port RF devices while operating in a target system such as a radar transmitter, including insertion gain, insertion phase, residual phase noise, error vector magnitude, AM noise, and group delay, all with increased accuracy, good repeatability, good dynamic range, and decreased measurement time.

Abstract: A triaxial testing system of material properties having top and bottom joint assemblies that rotate about and move along a longitudinal axis in response to forces imparted by a testing machine. The joint assemblies are connected together by horizontal and vertical linkage assemblies. The horizontal and vertical linkage assemblies are connected to horizontal and vertical loading and clamping assemblies to thereby transfer in-plane and multi-axial loads from the testing machine and the joint assemblies to a material test specimen. The test specimen is rigidly clamped to the horizontal and vertical clamping assemblies. The bases and ends of the test specimen are shaped for clamping and axial loading. Rigid plates may be disposed over ends of composite test specimens for spatially stabilizing such specimens during testing. The test specimens may include devices to measure and record the axial and shear loads, displacement and strains imparted to the specimens during testing.

Abstract: A method is presented for determining inner and outer boundary layer length scales from a succession of drag measurements of a cylindrical body in order to estimate flow noise and for computational modeling of the dynamics of towed arrays in a fluid medium. A succession of measurements of the total drag on a cylinder under tow at uniform known conditions (flow speed, fluid density, fluid viscosity, cylindrical body geometry) is taken. After each measurement, the cylinder is truncated by a fixed amount, and the process is repeated for the length of the cylinder. The measurements provide a spatially and temporally averaged measure of the mean wall shear stress and momentum thickness, from which the inner and outer length scales can be determined. The inner and outer boundary layer length scales may then be used for estimation of flow noise on towed cylindrical bodies and arrays.

Abstract: An amphibious antenna for providing Near Vertical Incidence Skywave (NVIS) communication when grounded to a conductive fluid. The amphibious antenna has a support member for supporting a helix. The helix includes a first helical arm that is not insulated and grounded, when in use, through a conductive fluid into which the antenna is placed, and a second helical arm that is insulated from the conductive fluid.

Abstract: A calibration method for radiometric imaging systems that relies on an absolute measurement of scene radiance (thereby requiring a baseline measurement of zero radiance), and a shutter assembly for taking the baseline measurement of zero radiance which is operable under cryogenic temperatures as low as 80.5K (?192.65° C.) in vacuums measuring <10?6 torr (mm Hg). The shutter assembly generally includes an actuator and a shutter mechanism. The actuator is preferably a miniature solenoid assembly capable of operation in extreme environments (e.g. vacuums of <10?6 torr, temperatures below 90K). The shutter mechanism preferably includes a single shutter blade and is also capable of operation when subjected to extreme environments. The method of using the shutter assembly provides a zero radiance reference measurement for an infrared imaging system, thereby providing a basis upon which absolute scene radiance may be determined.

Abstract: A tow cable in which the temperature of the cable is measurable by the use of multiplexing capability intrinsic to optical fibers in which the optical fibers are positioned at the center of the tow cable and wound as part of two layers of surrounding strength wires. The optical fibers of the two layers intersect a vector extending radially from the optical fiber at the center to an outer surface of the tow cable. Light signals emitted from a multiplexer to positions along the optical fibers, in which the positions intersect the vector, return light signals from the positions to provide measurements that in conjunction with a data processor further provide temperature measurement of the outer boundary of the tow cable.

Abstract: An apparatus including a gimbal and an antenna with a hollowed frustum having a closed end and an open end. The antenna includes a feed stem at the closed end extending as an internal rod into the hollowed frustum. The opposite end of the rod connects to a receiver section extending from an edge of the open end beyond a longitudinal axis of the antenna. The antenna is supported by the gimbal attachable to a container suitable for towing. A pivot at the open end in relation to the center-of-gravity of the frustum allows a swinging arc in relation to the attached gimbal in that the frustum moves by gravity toward the axes of the gimbal such that the receiver section maintains a facing position to the force of gravity.

Abstract: A marine surface vessel having a main hull and at least two lateral hulls disposed respectively on opposite sides of the main hull. The vessel includes an engine disposed in the main hull producing exhaust gas and cooling air, microbubble injectors disposed in subsurface areas of each of the lateral hulls, and conduits in fluid communication with the microbubble injectors. Upon operation of the engine, the exhaust and/or cooling air produced by the engine is directed by the conduits to the injectors to effect generation of microbubbles on the subsurface areas of the lateral hulls to occasion microbubble drag reduction on the lateral hulls.

Abstract: An oscillating appendage includes a vessel housing a supply of pressurized fluid with reinforced tubes selectively receiving the pressurized fluid from the vessel, an oscillating valve for controlling the supply of pressurized fluid from the vessel to the reinforced tubes, and a flexible skin encompassing the vessel, the reinforced tubes, and the valve. The flexible skin defines an outer shape of the oscillating appendage with a tail member affixed at a terminal end of the appendage to further propel the appendage by an oscillating motion of the appendage.

Abstract: A system for launching bodies from a submarine includes a pump for transferring seawater to an elastomeric ejection tank, and a check valve that permits transfer of the seawater to the tank, and closes upon filling of the tank. The valve includes a head and a seat, a stem having fixed thereon the head and a disk having a circular protrusion extending toward the seat, a cup mounted around the stem and having a circular depression in a surface thereof, and radially extending holes disposed in the cup. During valve closure, the disk protrusion enters the cup depression forcing water in the depression to exit the cup through a primary restrictive path of an annular gap between the protrusion and depression and a secondary restrictive path of the radially extending holes, to slow the valve head in movement during engagement with the valve seat.

Abstract: A method for encrypting and decrypting two-dimensional data is provided using a selected fractal a square fractal key matrix size and associated fractal computation initialization values. The fractal key matrix is computed iteratively, changing fractal parameters as necessary, to obtain a full rank fractal key matrix. Data to be encrypted is buffered in a two-dimensional matrix to allow matrix multiplication between the buffered data matrix and the fractal key matrix. The encrypted data, the encrypted data matrix dimensions, and the fractal parameters necessary to regenerate the fractal key are transmitted to a receiver that recreates the fractal key from the fractal parameters. The receiver additionally generates the fractal key matrix inverse. The data is decrypted by a matrix multiplication of the encrypted data and the fractal key matrix inverse.

Abstract: A encapsulation method of an acoustic sensor module and a resultant lightweight watertight acoustic sensor module for use in towed array retrieval systems. In the method, a composite is cast to encapsulate the support between end plates of the module, an exterior of a passage tube in which the array is retrieved, transducers positioned on the tube exterior and supporting telemetry lines for the transducers. The components, listed previously, are cast into a block of the cured composite such that the arrangement of the components is fixed. Residual composite emitting from an aperture of an end plate allows a conductor for the telemetry lines to be potted into the composite with an end of the conductor free from the composite thereby allowing connection to an external controller or generator.

Abstract: An elastomeric disk for use in an elastomeric ejection system in which a thickened curvature protrudes from both sides of a central plane of the disk. Integral to each curvature is an annulet which dovetails from the curvatures to a periphery of the disk. The thickness of the annulet in regard to the central plane is greater on the fluid pressure side of the disk thereby shifting material strain to the center of the disk during expanding deformation. The annulet shape is attachable to the elastomeric ejection system by a clamp of the system.