Abstract: An underwater location system (16) is disclosed having a plurality of locator modules (18), each capable of finding the relative range and bearing of other modules. The modules may be diver mounted, placed on movable objects such as a boat (14) or on fixed positions such as the sea floor (12). Range and bearing to each module of the system is displayed, upon request, on a console (20) which may be hand held or mounted in a diver's instrument console. Each module can interrogate other modules with an acoustic pulse which is answered, after a unique time delay stored in each module, by an acoustic response pulse. Response pulse sources are identified by their arrival in a time detection window set by their unique time delay. Range to each identified transponder source is calculated from a receipt time within each detection window.

Abstract: Apparatus is provided for use with a conventional shell reloading machine of the type represented by the well-known "Hornady 366 Auto Reloader" commercial machine, such apparatus comprising a carrier holding a plurality of storage tubes filled with respective columns of replacement primers, the carrier being adapted for mounting on the superstructure of the machine in upstanding position so that each tube can be positioned, in turn, relative to that operating station of the machine that is normally occupied by a single such tube for discharging its replacement primers into receiving shells carried therebelow by a turntable of the machine. Removable hitchpins or the like at the bottoms of the respective storage tubes in the carrier prevent the descent by gravity of the respective columns of replacement primers. The hitchpin is removed from the bottom of each storage tube that is placed into primer-discharging position.

Abstract: A continuous wave driven ultrasonic transducer for determining doppler frequency shift in reflected ultrasonic pressure waves in which the transmitter and receiver sections are constructed of a composite core having a plurality of segments of piezoelectric material separated by acoustic suppression material. Also disclosed is a method of reducing acoustic and mechanical cross coupling between piezoelectric transmitter and receiver sections of an ultrasonic transducer by arranging segments of piezoelectric material in a lateral array, and separating the piezoelectric segments with ultrasonic acoustic suppression material to produce a composite transducer core of reduced acoustic and mechanical cross coupling.

Abstract: The present invention relates to methods of seismic exploration utilizing vibrationally generated, elliptically polarized shear waves in an earth medium for subsequent detection of one or more dimensions of orthogonal particle motion. The invention relies upon a shear wave source of a type which couples a continually rotating longitudinal force into an earth medium thereby to propagate an elliptically polarized shear wave for refraction, reflection or subsurface detection, various forms of exploration being well within the capabilities.

Abstract: A portable device for accurately measuring acoustic velocities in solids. This portable hand-held device (100) uses dual receiving transducer tips (110, 112) to allow differential measurement of acoustic velocity in a solid. A body having a handle uses a transmitting transducer tip (108) to transmit acoustic energy to a solid. The first receiving transducer tip (110) is used in conjunction with a second receiving transducer tip (112) mounted on the body a fixed distance from the first (110). The device (100) uses the differences in the time of arrival of the wavefront at the first and second transducers to calculate the acoustic velocity in a given solid. This differential measurement method reduces acoustic velocity measurement inaccuracies.

Abstract: In seismic surveys at sea, with seismic devices, especially sources of seismic energy being towed behind a vessel and kept at a mutual configuration relative to each other, and with the devices being suspended from a buoyancy member (1) mechanical structure of the equipment permits undesirable forces which influence the sources of seismic energy (3), especially during firing, to be absorbed. Mutually arranged flexible, resilient members (4) are provided between the suspension line of the seismic devices (3) and the seismic devices (3) and/or between the seismic devices. Seismic devices are supported on two or more rigid fastening members (5) and flexible resilient members (4) extend between the fastening members and the suspension line. The flexible resilient members (4) preferably extend in a curved path between the fastening members (5) and the members together form an integrated unit.

Abstract: In accordance with the present invention, several methods are presented for the detection of gas into an offshore marine riser (e.g., riser gas). In a first embodiment of this invention, an acoustic transmitter is positioned on or nearby the subsea blowout preventor stack and imparts continuous low frequency waves into the annular fluid in the marine riser. These imparted waves define pressure perturbations which are received by a pressure transducer positioned on the riser at a location above the acoustic transmitter. Gas detection in the riser is then indicated by determining the rate of change of certain characteristics of the output. The output characteristics are preferably the moduli and phase angles of the acoustic fundamentals and their harmonics.

Abstract: Novel means for deploying airplane wing flaps feature a bent shaft which is translatable fore and aft in the fairing cavity. The shaft has an adjacent follower member which travels in a concentric curved flap track to rotate shaft as it extends. The bent shaft has a support ball fitting and end roller which provide flap deflection with respect to the fixed wing as the shaft is extended aft and rotated. The subject flap deployment means are mechanically elegant resulting in lower manufacturing and installation cost and high reliability.

Abstract: A capacitive transducer including a back plate and a tensioned dielectric diaphragm with a conductive layer is operated as a sonic energy emitter and receiver. The polarity of the dc bias applied to the transducer is periodically reversed to prevent charging and polarization of the dielectric diaphragm due to the applied electrostatic field. The bias voltage polarity is controlled in timed sequence with the application of a fluctuating voltage to generate sonic energy with optimum efficiency. Electrical signals resulting from received sonic energy are selectively inverted and provided with compensation for differences resulting from differences in bias polarities.

Abstract: A damped flexible seal assembly for a torpedo isolates the tailcone thereof rom vibrational energy present in the drive shaft assembly. A pair of outside flanges, each of which include an inwardly facing groove and an O-ring constrained therein, provide a watertight seal against the outer non-rotating surface of the drive shaft assembly. An inside flange includes an outwardly-facing groove and an O-ring constrained therein, and provides a watertight seal against the inner surface of the tail cone. Two cast-in-place elastomeric seals provide a watertight seal between the flanges and further provide a damping barrier between the outside flanges and the inside flanges for damping vibrational energy present in the drive shaft assembly before the energy can reach the tailcone through the seal assembly.

Abstract: A seismic logging system for VSP or cross well data capture set forth. It is comprised of M duplicate recording stations connected serially below a main structure suspended on a logging cable. Each of the recording stations preferably includes orthogonally arranged displacement transducers, and they are in turn connected with suitable amplifiers, filters and converters to form digital words, and the digital words are recorded in organized fashion in a memory. A telemetry unit is connected to that memory for transfer of data. This data transfer takes place over a short distance into the main unit, and the main unit includes a much larger memory for storing and holding data from M recording stations deployed along and there below in the well borehole, and further including telemetry means for transfer of data along the logging cable.

Abstract: A compact, marine acoustical source is disclosed. More specifically, the present invention relates to a marine acoustical source capable of producing a strong primary pulse while substantially suppressing or eliminating undesired secondary pulses derivative from said primary pulse.

Abstract: A seismometer system which provides readouts of the time integral (Cumulative Absolute Velocity or CAV) of the acceleration time history of an earthquake. CAV is found to be a measure of the structural damage potential of an earthquake. Three triaxial low frequency acceleration sensors are connected into a digital computer system. Each sensor has a capacitive pickoff, whose capacitances determines the length of an electrical pulse; the pulse gates high-frequency clock cycles into a counter. The counts are summed to give the time integral. A microprocessor provides for periodic re-zeroing and other calibration functions, and for the actuation of alarms, relays and electrical pulses for utility shutoff and the like at predetermined levels of CAV. The acceleration time history of the earthquake is stored in the memory for later retrieval if desired. The whole system is contained in a small inexpensive package.

Abstract: A low-frequency hydrophone for a sonar array comprises at least a lacunary ceramics element with open porosity saturated by a viscous fluid, on which metal electrodes have been deposited. This hydrophone forms a high-pass filter whose cutoff frequency is adjusted by modulating the area of the electrodes. The present invention may find particular application in towed linear arrays and passive sonars.

Abstract: A sleeve for a seismic air gun exhaust chamber is disclosed. The sleeve prevents water from accumulating in the air gun exhaust chamber when the air gun is vertically positioned and provides a convenient method for regulating the volume of the air gun exhaust chamber, and thus the frequency of acoustic energy emitted by the gun. The sleeve is characterized by a false bottom which is connected to the main chamber by an orifice and passages.

Abstract: A non-destructive method of measuring physical characteristics of sediments to obtain a cross-sectional distribution of porosity and permeability values and variations, and of shear modulus and shear strength. A pair of boreholes have borehole entries spaced apart from each other at a predetermined distance, and a plurality of hydrophones are spaced at predetermined known positions. A source of seismic energy is placed into another borehole and activated to transmit seismic wave energy from the source to the hydrophones. Seismic wave characteristics are measured in a multiplicity of paths extending from the source to the hydrophones, using cross-bore hole tomography.

Abstract: A piezoelectric transducer having electrodes formed on both surfaces has a piezoelectric base molded as a curved plate which can converge sound fields of acoustic waves at an arbitrary point and which can reduce noise or reverberation in a lateral direction which otherwise occur due to unnecessary vibration. At least one of the electrodes is divided concentrically. A material having a small electromechanical coupling factor K.sub.p in the lateral direction is used for the piezoelectric material, preferably porous PZT.

Abstract: Disclosed is a sonar for avoiding sub-surface underwater objects, for a surface vessel, having its directivity in elevation optimized to observe the surface and its surface reverberation reduced to the minimum. It consists in using an acoustic antenna having two columns of n transducers, the first column insonifying, at transmission, an elevation sector corresponding to the collision-risk zone and forming channels at reception, in the insonified elevation sector, the width of the channels being all the finer as the desired precision of the measurement of the position in elevation is high. The second column is necessary for the localization in relative bearing. The disclosure can be applied to the precise localization in elevation of objects located in the path of a vessel.

Abstract: A seismic receiver array device for shallow water and near-shore operations which is comprised of an elongated low-profile, flexible casing having a plurality of geophones and hydrophones spaced along its length, and the geophones and hydrophones are electrically connected to a transmitter for transmitting the seismic impulses into a master receiver. Spikes are extended downwardly at spaced intervals along the length of the casing and a setting tool is provided to releasably anchor the spikes into the earth below a body of water.

Abstract: A tool and corresponding method for removing folds and buckles in the matal of a propellant containment bag, in a round of ammunition, prior to the addition of explosive propellant. The tool includes a plurality of flexible fingers that are inserted into the propellant containment bag through the primer cap aperture. Once inside, the flexible fingers are expanded, pressing the propellant containment bag against the inside of the cartridge case. The tool is advanced to the far end of the propellant containment bag, thereby pulling taut the entire bag. The flexible fingers extend around the tail end of the projectile of the ammunition round, removing folds in the propellant containment bag that may interfere with the dispersion of propellant around the stabilizer fins or other features of the projectile's tail end, when propellant is subsequently added.