Abstract: An aircraft system which provides the pilot with a continuous cockpit reat of the weight and center of gravity of an aircraft carrying an externally lifted load together with the impact on aircraft controllability of load shifts and fuel burnoff, by transmitting input signals from load cells installed in the lifting hook system, input signals from a fuel totalizer, and input data from a system keyboard to a system computer.

Abstract: A broadband angle-beam transducer system for producing and/or receiving Reigh waves on the surface of a metal medium comprising a thickness mode piezoelectric polymer transducer element embedded within and impedance matched to a plastic wedge. The transducer element is oriented at an angle determined to be the critical angle for Rayleigh waves in the metal structure to be tested. As a transmitter, the transducer element generates discrete dilatational wave pulses, one of which propagates within the plastic wedge to the plastic face in contact with the metal structure. At this face some of the wave energy is reflected as dilatational and shear waves within the wedge and the remainder of the wave energy passes through a coupling medium into the metal structure producing a Rayleigh wave traveling along the surface of the structure.

Abstract: A termination tip for submarine buoyant cable antenna systems can quickly converted from grounding to insulating and vice versa any number of times. The nosepiece assembly fits over a pin contact of wire and is screwed onto a connector that holds the wire. An O-ring between the wire and the nosepiece assembly seals out seawater. The nosepiece assembly is either insulating or conducting depending on the desired configuration.

Abstract: Process for making densified ternary sulfide ceramics as infrared window erials using sulfide compounds MLn.sub.2 S.sub.4 belonging to the Th.sub.3 P.sub.4, CaFe.sub.2 O.sub.4 and spinel structure types. These refractory sulfides show good sinterability especially when fired in flowing hydrogen sulfide, and they can be densified by a combination of hot-pressing and hot-isostatic pressing into ceramic pieces approaching their theoretical density with closed pores and which have good transmission characteristics in the infrared region.

Abstract: The novel multi-beam multi-lens antenna of the present invention provides multi-beam coverage over a hemisphere or greater three-dimensional spatial coverage region. In its simplest configuration, the antenna comprises two microwave lenses whose design is integrated to minimize path length errors and aberrations for beams over a 360.degree. azimuth coverage range. The antenna comprises a 3-D focal ring bootlace first microwave lens that is a figure of revolution and a non-planar dome second microwave lens which provides the refractive properties necessary to obtain the hemispheric coverage while providing additional degrees of freedom necessary to reduce errors and aberrations of the lens system to within acceptable levels. Both lenses are time delay lenses to effect broadband operation and are circularly symmetric. This symmetry results in antenna performance that is invariant with azimuth beam position.

Abstract: A narrow band compensating beamformer for a receiving array that conforms some surface other than a plane and thus is, in general, three dimensional. The array comprises a number of sensing elements arranged in a non-planar pattern. Each sensing element has its output signal delayed or phase shifted as a function of the receiving angle by the beamformer in such a way as to produce an equivalent "projected planar array" in a particular direction. This arrangement has the same beam pattern in the selected direction as an equivalent planar array with its lower side lobe characteristics permitting the taking of advantage of well known, low side lobe shading techniques.

Abstract: A plurality of transducers, closely conforming to the surface of a low-drag ose, are baffle mounted in close pack configurations to eliminate grating lobes. The baffle assembly is mounted outside a pressure hull within a thin acoustically transparent fairing. A plurality of pressure compensators also attach outside the pressure hull. The cavity between pressure hull and fairing is filled with pressure compensating acoustic fluid. Larger portions of unused volume are first filled with a syntactic foam to minimize the amount of fluid required. The pressure compensators balance fluid pressure against external sea pressure to prevent fairing collapse. This array maximizes available nearby internal nose volume thus allowing beamforming electronics to be located within the pressure hull in close proximity to the array elements, connecting thereto via a plurality of short coaxial cables.

Abstract: A multimode hydrophone of small diameter and low weight providing dipole ectivity patterns over a decade range of low frequencies by utilizing a pair of orthogonal dipole signals and a nondirectional reference signal to eliminate directional ambiguity. Each multimode hydrophone is a thin wall tube divided electrically into quadrants which permits differencing or opposing halves to produce signals with dipole directivity patterns and the formation of a nondirectional reference signal by summing all four quadrants. The hydrophone tube comprises inert and piezoelectric materials, selected and combined so as to shift the resonant frequency of the tube lower while keeping the over-all tube diameter as small as possible.

Abstract: Apparatus and method for nondestructive detection of loose parts or faulty onds in sound transducers by measuring erratic second-order nonlinear difference-frequency responses of the test transducer to a pulsed high level dual-frequency sound field produced by a high power projector. Such field may be generated by combining a high frequency carrier signal at frequency f.sub.o with a low frequency tone burst signal at frequency f/2 in a double balanced modulator so as to produce the dual-frequency pulse at f.sub.o +f/2 and f.sub.o -f/2. The test transducer converts the dual-frequency pulse into a plurality of linear and nonlinear frequency components including the difference-frequency f.

Abstract: A frequency independent log periodic acoustic device is utilized for the transmission or reception of underwater sound. The acoustic device when used in conjunction with any substantially plane wave receiving or transmitting transducer produces a directional, substantially constant beamwidth diffraction pattern for radiation or reception of underwater sound signals. A key element of the device is a particularly shaped plate or diaphragm, called a filter plate, made of stainless steel or other material having suitable acoustic properties. The filter plate on being placed in front of any plane wave receiving or transmitting transducer acts automatically to make the beamwidth of the diffraction pattern of the combined device constant, regardless of frequency. This is achieved by automatically making the effective aperture diameter of the filter plate-transducer combination a constant multiple of the acoustic wavelength of the sound in the underwater medium.

Abstract: A multichannel fiber optics connector comprises two virtually identical hes, each of which is made up of an insert alignment bushing, a shell and a clamping nut. The bushing has anchor and keying pins attached. The connector is waterproof and pressure tolerant for underwater use.

Abstract: A compact subwavelength size monopole underwater sound radiator has chararistics to maximize resistive radiation impedance, minimize reactive radiation impedance, facilitate heat dissipation and minimize compensating air usage. This results in improved efficiency, bandwidth and use factor. The underwater sound radiator uses two back-to-back mounted, frustum shaped, hollow, radiating shells to achieve radiation characteristics approximating those of an equivalent sized pulsating sphere. An elliptically shaped, uniform cross-section magnetostrictive ring crossed by a linear piezoelectric spreader comprises a compact eclectic driver. Both the magnetostrictive ring and the piezoelectric stack contribute to the output through inverse phase cyclic changes in their respective lengths those changes being added and amplified by the flexural-bow type action of the elliptically shaped magnetostrictive ring.

Abstract: The disclosed molecular excimer laser discharge tube employs a transverse ectrical discharge with a UV preionization. The discharge tube is made of pure quartz with two optical quality windows fused onto the two ends. The mechanical support and electrical feedthrough for the profiled molybdenum cathodes are provided by commercially available quartz molybdenum cup seals. The anode is made of perforated molybdenum sheet and is supported by slots formed in quartz plates. The preionization for the main discharge is generated from "V" cuts provided in a molybdenum ribbon sealed in a quartz tube.

Abstract: Composites of lead zirconate titanate (PZT) and inactive polymers with 3-1 and 3-2 patterns and a method of fabrication thereof are described. Fabrication is accomplished by drilling holes in sintered PZT blocks and filling the holes with epoxy or some other inactive polymer. The influence of hole size and volume fraction PZT on the hydrostatic properties of the composite is evaluated. By decoupling the piezoelectric coefficients d.sub.33 and d.sub.31 in the composite, the hydrostatic coefficients are greatly enhanced.

Abstract: A wide-area acousto-optic hydrophone which uses signal and reference laser beams together with interferometric methods for detecting underwater acoustic signals. The signal beam is distributed across the wide sensing area of the hydrophone using beam folding techniques while being directly transmitted through a sensing chamber filled with an optically transparent bulk material, the refractive index of which varies with the incident acoustic pressure thereby modulating the signal beam. Concurrently, a reference beam of equal length and folded in an identical pattern is directly passed through an adjacent chamber filled with the same bulk material. A microhole joins the two chambers, to expose the reference beam to the same static pressure and temperature fluctuations as the signal beam thus serving as a low pass filter.

Abstract: An ellipticized singlet azimuth versus elevation optimized and aperture eemized nonspherical acoustic lens antenna of very low or even minimal F-number providing balanced astigmatism for wide angle acoustical applications in underwater sound is described. The acoustic lens has an elliptical periphery and surfaces defined by a system of nonlinear partial differential equations, the surfaces acting together to produce two perfect primary off-axis foci F and F' at a finite distance in back of the lens and two perfect conjugate off-axis foci F.sub..infin. and F'.sub..infin. in front of the acoustic lens at infinity; i.e., the lens simultaneously focuses energy from the primary foci F and F' into two off-axis parallel ray plane wave sonic beams directed towards infinity at equal but opposite angles with respect to the acoustic lens axis.

Abstract: A method for obtaining a very low resistance ohmic contact on p-type Indium hosphide (InP) by light-assisted plating of Au and Zn. The plating technique, which uses alternating positive and negative current pulses, has been used for producing patterned, small area contacts on device structures and is compatible with established n-type ohmic contacting procedures.

Abstract: A high resolution scanning beamformer for a soundhead having a circular or a cylindrical array of hydrophones uses charge coupled devices as transversal filters in a plurality of first stage quadrature sampled phase shift steered beamforming modules. In a second stage, serial-in/serial-out charge coupled devices are used to correct for fill time. The sonar focuses at all nearfield ranges of interest by controllably varying a clocking rate.

Abstract: A method and apparatus for eliminating the effects of ionizing radiation on computer system are disclosed in which two redundant storage units are alternately addressed and updated in rapid succession so that each storage unit alternately carries information unaffected by the radiation. After the radiation has ceased, this unaffected unit is located and its information read back into the computer system.

Abstract: A cycle for a heat driven heat pump using two salts CaCl.sub.2.8NH.sub.3 and ZnCl.sub.2.4NH.sub.3 which may reversibly react with ammonia with the addition or evolution of heat. These salts were chosen so that both ammoniation processes occur at the same temperature so that the heat evolved may be used for comfort heating. The heat to drive the system need only be slightly hotter than 122.degree. C. The low temperature source need only be slightly warmer than 0.degree. C.