Abstract: The method and apparatus for providing elliptical polarized shear waves in a marine environment in which a shear wave source penetrates the surface sediment of a water bottom includes dual actuator/reaction mass system mounted inside a structural ring of a conical housing section. A cross shaped structure at the top of the apparatus serves as a passive reaction mass and as a moment arm support for reversibly motor driven propellers enclosed in shrouds at the outer ends of the cross shaped structure. A thruster system provides dynamic positioning. The cross shaped structure and housing section are connected by a structurally stiff member, such as a vertical tube. Pistons provide actuation of two reaction masses located within the housing structure, and the motions of the reaction masses generate shear waves which propagate in the subsurface formations.

Abstract: An ultrasound apparatus has a first group of transmission and reception channels that are respectively allocated to elementary transducer in the active aperture of a connectable transducer array. The central transmission location generated by a transmission channel and the reception location sampled by a reception channel coincide and lie on the allocated elementary transducer. In addition, a second group of transmission and/or reception channels is present, each being respectively simultaneously connectable to a plurality of elementary transducers via transmission and/or reception transfer stages for generating a virtual transmission and/or reception location that lies between the elementary transducers.

Abstract: An underwater acoustic projector including a Class IV flextension shell, preferably in the form of an ellipsoid, is connected to and driven by two substantially identical electromagnets having mutually opposing pole faces and having a common spatially uniform air gap which is centered between the pole faces. The coils of the two electromagnets are connected in series and when excited by a controlled current, generate a mutually attractive variable reluctance force which causes the pole faces to be attracted toward one another. The shell secured to the electromagnets elastically flexes along one of two mutually perpendicular axes resulting in a volumetric displacement of the outer surface of the shell.

Abstract: A metallic down hole seismic sensor cable for operating at temperatures up to about 400.degree. F. and pressures up to about 5000 psig is provided. The seismic sensor cable includes a flexible metallic conduit sized for receiving a seismic sensor, and means for transmitting output generated by the seismic sensor. The cable is preferably constructed of stainless steel. An inert curable heat resistant material substantially fills the unoccupied spaces of the assembled seismic sensor cable.

Abstract: An outer jacket (14), an inner jacket (15) and an explosive charge (16) are ach independently manufactured on one of three parallel production lines (1, 2, 3) and assembled on a contiguous assembly line (4). The jackets (14 and 15) are designed to have a sufficient shape stability to be handled as separate components, and obtain the required firing strength due to their assembly. By changing the inner jacket (15), the ammunition body manufactured in this way can be prepared with different active bodies as suited for the application intended.

Abstract: The invention relates to a frequency controlled motor driven low frequency sound generator. The low frequency sound generator consists of an open resonator (2) arranged as a sound emitter for generating standing gas-borne sound waves which produce a varying gas pressure inside the resonator, and a feeder unit (1) for a modulated supply of air pulses to the resonator. The feeder unit (1) comprises a motor driven piston (8) with an approximately sinusoidal volume velocity. The piston is mounted on a piston rod (7) which is connected to a flywheel (6). The flywheel, in its turn, is mounted on a shaft (5) which is driven by a motor (3). The motor speed and thereby the frequency of the piston is regulated by a special electronic control unit.

Abstract: A sonar transducer assembly is provided which is adapted to be mounted on the transom of a boat. The assembly includes a shaped transducer device comprising a housing having a base portion of substantially elliptical cross section and a nose of a flattened ellipsoidal shape. A connector stem having a faired leading edge connects the transducer housing to a mounting bracket assembly. The mounting bracket assembly includes a base member adapted to be connected to the transom and a pivotable member which supports the transducer device. A releasable connection between the members includes a pair of laterally spaced, outwardly extending projections on one member which engage ears formed on the other member. An elastomeric insert disposed between the arms controls the force necessary to cause release of the connection to provide "kick-up" when the transducer device strikes an object in the water.

Abstract: The disclosure is directed to a circuit for producing electrical discharges in response to trigger signals, and a form of the disclosure is directed to an apparatus, which includes such a circuit, for determining the transit time of acoustic energy travel between a transmitter location and a receiver location.

Abstract: The sonar transducer includes a metal core about which is situated a cylindrical piezoelectric ceramic ring element with paper interposed therebetween. In order to improve resistance to fracture resulting from mechanical shock, in one embodiment, the core is reduced in diameter, such that a potting compound can be situated between the paper and the ring. In a second embodiment, the ring element is divided into two individual, axially aligned cylindrical ring subelements with a gasket interposed therebetween.

Abstract: A method and apparatus for compensating sensitivity fluctuations in signals received from respective groups of hydrophones for the purpose of subsequent signal processing, the groups being arranged in a predetermined sequence (0, 1, 2, . . . i) to form a transducer arrangement, wherein the received signals are influenced by the sensitivity of the hydrophones and/or the gain of preamplifiers connected to the outputs of the hydrophones. The energy value (W.sub.i) for the received signals of each group of hydrophones is determined and a median energy curve (W.sub.m (.theta.)) is derived from the energy values (W.sub.i) as a function of the sequence of the groups of hydrophones. A correction value is formed for the signals received from each group of hydrophones from a comparison of the respective energy value (W.sub.i) with the energy curve (W.sub.m (.theta.)) and the received signals are corrected with the correction value.

Abstract: A method and apparatus for nuclear logging, and in particular, neutron porosity logging is presented. In accordance with the present invention, a novel programmable gain amplifier circuit and a novel peak detector circuit are used in conjunction with other electronic circuitry to provide borehole formation logs in a nuclear logging tool.

Abstract: Motor-control device for an image forming apparatus includes a motor, an encoder, a microcomputer, and a driving circuit. The encoder generates a pulse signal in response to rotation of the motor. The microcomputer includes a CPU, a RAM and a ROM. The CPU detects actual rotational speed of the motor based upon the pulse signal generated by the encoder. The CPU cyclically provides a driving signal by comparing the actual rotational speed with a predetermined target rotational speed of the motor. An operating cycle is proportional to a cycle of the pulse signal generated by the encoder. The driving circuit drives the motor based upon the driving signal provided by the CPU. The CPU determines the operating cycle based upon the predetermined target rotational speed. The CPU also determines whether the motor condition is normal or abnormal by comparing the driving signal with a predetermined reference driving signal.

Abstract: The cleaning device comprises a dummy disc having at least a hole covering an area in which a control signal is to be recorded, a flexible disc member coaxially arranged on the dummy disc and secured thereto at an inner periphery thereof and a cleaning member attached on one surface of the flexible disc facing to the dummy disc and protruding downwardly through the hole of the dummy disc. The cleaning device is set on a turn table integrally attached to a rotary shaft of the disc player and made in light-pressure contact with an optical pick-up raised so that a lens surface of the pick-up is wiped away thereby during its horizontal movement. In a case where the lens collides with the cleaning member, the cleaning member is pushed up by the lens through the hole of the dummy disc due to the flexibility of the flexible disc, so that a mechanical damage of the lens surface is prevented.

Abstract: A driving current control circuit capable of controlling the logarithmic base current of two transistors in a current driver to control a drive current for a motor. This control circuit controls the current of the current regulator depending on a control signal, thereby controlling the driving current for the transistors in the current driver. The control circuit includes an output current mirror composed of two output-side transistors and a single input-side transistor. The two output-side transistors control the inflow and outflow of the driving current for the current driver. A single phase compensating condenser is connected to the input-side transistor. This arrangement makes the entire circuit simple and compact and causes an improved controlling characteristic.

Abstract: A controlling apparatus for an induction motor for controlling the induction motor in high efficiency having a converter for supplying an electric power to the induction motor, a rotational speed detector of the induction motor, a controlling means of the converter for holding a torque of the induction motor constant while the rotational speed of the induction motor is lower than a base rotational speed and to decrease a secondary magnetic flux of the induction motor according to the rotational speed while the rotational speed of the induction motor is over the base rotational speed, and a means for varying the secondary magnetic flux according to a terminal voltage of the induction motor so as to hold the terminal voltage a predetermined constant voltage while the rotational speed of the induction motor is higher than the predetermined speed.

Abstract: In a plural phase electric motor, a control method senses regeneration current from a non-energized phase and commutates to the next state. In the next state, the unenergized phase of the present state is energized in a polarity opposing the regeneration current of the present state, such that during the next state, energization current is directed in the last noted phase in a direction opposite to the regeneration current of the present state. In the state prior to the present state, the unenergized phase of the present state is energized in a polarity aiding the regeneration current of the present state, such that during the prior state, energization current is directed in the last noted phase in the same direction as the regeneration current of the present state. In the preferred embodiment, all of the commutation switches are periodically simultaneously turned off for a given blanking interval, and the regeneration current is sensed on a common DC bus during such interval.

Abstract: A polyphase induction motor is driven from an inverter having a set of switches activated in prescribed on-off patterns to provide forward and reverse voltage vectors and a zero vector for controllably energizing the motor. Memories are provided on which there are written forward voltage vector data for forwardly energizing the motor, reverse voltage vector data for reversely energizing the motor, and zero vector data for de-energizing the motor. The voltage vector data and zero vector data are selectively read out from the memories in order to cause the inverter to generate in real time the corresponding voltage vectors and zero vectors needed for the motor to be quickly revolved to, and set out of rotation exactly in, a desired angular position. For such optimum motor speed control an ideal control curve is predefined which represents the ideal relationship between the motor speed and the difference between the actual and the desired angular position of the motor.

Abstract: A piezoelectrically-driven, resonant-pipe projector has formed therein vents to broaden the response of certain cavities resonances and to increase the response between these resonances. The projector exhibits a relatively high electroacoustical efficiency, is capable of medium to high power output over the operating band, and is not depth dependent or depth limited.

Abstract: A fluid strainer and flow corrector for use with a fluid flow measurement device, such as a turbine-type flow meter, consists of a generally conical grid of ribs attached to an annular base flange. The base flange of the strainer/flow corrector fits into a groove formed on the inlet side of the housing of the flow meter and is held in place by means of a flexible snap-ring. The strainer/flow corrector is arranged with its apex upstream of the flange portion with respect to the direction of fluid flow through the inlet of the flow meter. The spacing between the ribs is chosen as to block the flow of debris which might be present in the fluid flowing through the flow meter. The spacing between the ribs is also chosen to provide a desired velocity profile to the fluid. The strainer/flow corrector may be easily removed or replaced without disconnecting the flow meter from its associated pipework.

Abstract: An aircraft windshield system which employs a relatively thin outer windshield member in combination with a thicker ballistic protection inner windshield member and a plurality of electively disposable specific threat protecting panel members is disclosed. The specific threat protecting panel members are arranged for storage during normal peacetime use of the aircraft, and for rapid and selective deployment into protecting positions when elected by the aircrew or as determined by a mission knowledgeable computer apparatus or other means. The results of studies indicating the desirability of multiple-panel windshield structures from both cost and performance viewpoints are also disclosed. The disclosed windshield system is especially applicable to future military aircraft such as the Advanced Tactical Fighter (ATF) and Advanced Tactical Bomber, and may also be retrofitted to existing aircraft for upgrading purposes.