Abstract: A defrosting (or de-icing) system mountable on a surface of a mechanical part to be de-iced, comprising including a piezoelectric actuator, a fastening device to secure the actuator to the surface, and at least one control unit to activate the actuator to excite the part for defrosting. The actuator features a stacked structure of prestressed piezoelectric elements along its longitudinal axis. The fastening device secures the actuator parallel to the surface and includes fastening elements at each end, enabling excitation of the part in extension and bending modes.

Abstract: An electrical power production system including a plurality of generator assemblies having: at least one piezoelectric generator for generating electrical power in response to a mechanical force applied onto said first generator, an actuator for applying a mechanical force onto the generator when said actuator is biased, a rotatable cam having a cam surface, a follower means for following the cam surface, a lever connected to the follower means, said lever being mounted as a lever arm and engaging with the actuator so as to bias said actuator when the cam is rotated and the cam surface exerts a mechanical force on the follower means, a rotatable wheel rotated by a power source and coupled to the cams so that setting said rotatable wheel in rotation at a rotation speed causes the rotation of said cams at another rotation speed, which is greater than that of said rotatable wheel.

Abstract: An electrical power production system including a plurality of generator assemblies having: at least one piezoelectric generator for generating electrical power in response to a mechanical force applied onto said first generator, an actuator for applying a mechanical force onto the generator when said actuator is biased, a rotatable cam having a cam surface, a follower means for following the cam surface, a lever connected to the follower means, said lever being mounted as a lever arm and engaging with the actuator so as to bias said actuator when the cam is rotated and the cam surface exerts a mechanical force on the follower means, a rotatable wheel rotated by a power source and coupled to the cams so that setting said rotatable wheel in rotation at a rotation speed causes the rotation of said cams at another rotation speed, which is greater than that of said rotatable wheel.

Abstract: An electroacoustic transducer submersible in an immersion fluid (8) for underwater acoustic communications, includes two horns (3a, 3b), a counterweight (4), two electroacoustic motors (1a, 1b), aligned along an axis of symmetry (6), the opposite ends of the motors being respectively connected to a horn, the unit consisted by the electroacoustic motors, the counterweight and the horns being able to generate a longitudinal electroacoustic resonance mode. The transducer includes a rigid and hollow cylindrical part (5) extending around the counterweight, the cylindrical part having an axis merged with the symmetry axis of the transducer, the inside of the cylindrical part forming a fluid cavity able to be filled with the immersion fluid, the electroacoustic motors and the cylindrical part being so dimensioned that the fluid cavity forms an acoustic coupling between the longitudinal electroacoustic resonance mode and a circumferential resonance mode of the cylindrical part.

Abstract: An acoustic antenna includes an array of elementary submarine transducers, each elementary transducer including, between a counterweight and a horn, at least one ceramic. Each elementary transducer is mounted on a printed circuit so that the printed circuit is clamped between the ceramic and counterweight thereof. The printed circuit includes conductors for connection to electrodes of the respective ceramic for individual control of the elementary transducers. The weight of each element of the elementary transducer is set to minimize cross-talk between channels.

Abstract: An acoustic wave transducer includes at least one electroacoustic motor, a horn having an inner wall and an outer wall, a counterweight, and a hollow housing having an inner wall and an outer wall and at least one acoustic opening. The electroacoustic motor is connected to the horn and to the counterweight along an axis, and the electroacoustic motor is capable of exciting the horn at about at least one resonance frequency. The housing is connected to the counterweight and surrounds the motor and the horn, the outer wall of the horn being arranged opposite an acoustic opening of the housing, and the space between the inner wall of the housing and the inner wall of the horn defines a cavity that contains a fluid. The transducer includes acoustic attenuation elements connected to the outer wall of the housing in order to attenuate the emission and/or reception acoustic waves at the frequency at least in a direction transverse to the emission/reception axis.

Abstract: A Bragg grating fiber hydrophone, includes a fluid chamber and an optical fiber in which a Bragg grating is integrated, the optical fiber passing through the fluid chamber along a longitudinal axis such that the Bragg grating is positioned inside the latter. The fluid chamber is filled with a compressible fluid and is defined by a casing including two ends connected to the optical fiber. The casing includes at least one portion formed by an extensible and compressible tube extending along the longitudinal axis. The portion formed by an extensible and compressible tube includes an outer end coinciding with one of the two casing ends and can be longitudinally deformed by a difference in the pressures applied on the walls thereof, which results in a variation of the length of the optical fiber as measured by a variation in the wavelength of a luminous flux extracted from the optical fiber.

Abstract: The disclosure includes a method of acquiring high-resolution ultrasound images using an array of transducers using successive transmission matrices.

Abstract: An electroacoustic transducer submersible in an immersion fluid (8) for underwater acoustic communications, includes two horns (3a, 3b), a counterweight (4), two electroacoustic motors (1a, 1b), aligned along an axis of symmetry (6), the opposite ends of the motors being respectively connected to a horn, the unit consisted by the electroacoustic motors, the counterweight and the horns being able to generate a longitudinal electroacoustic resonance mode. The transducer includes a rigid and hollow cylindrical part (5) extending around the counterweight, the cylindrical part having an axis merged with the symmetry axis of the transducer, the inside of the cylindrical part forming a fluid cavity able to be filled with the immersion fluid, the electroacoustic motors and the cylindrical part being so dimensioned that the fluid cavity forms an acoustic coupling between the longitudinal electroacoustic resonance mode and a circumferential resonance mode of the cylindrical part.

Abstract: A Bragg grating fiber hydrophone, includes a fluid chamber and an optical fiber in which a Bragg grating is integrated, the optical fiber passing through the fluid chamber along a longitudinal axis such that the Bragg grating is positioned inside the latter. The fluid chamber is filled with a compressible fluid and is defined by a casing including two ends connected to the optical fiber. The casing includes at least one portion formed by an extensible and compressible tube extending along the longitudinal axis. The portion formed by an extensible and compressible tube includes an outer end coinciding with one of the two casing ends and can be longitudinally deformed by a difference in the pressures applied on the walls thereof, which results in a variation of the length of the optical fiber as measured by a variation in the wavelength of a luminous flux extracted from the optical fiber.

Abstract: The invention relates to an acoustic wave transducer that includes at least one electroacoustic motor (1, 21), a horn (4, 24) having an inner wall and an outer wall, a counterweight (5), and a hollow housing (8, 28) having an inner wall and an outer wall and at least one acoustic opening. The electroacoustic motor is connected to the horn (4, 24) as well as to the counterweight (5) along an axis (7), and said electroacoustic motor (1, 21) is capable of exciting the horn at about at least one resonance frequency f. The housing (8, 28) is connected to the counterweight (5) and surrounds the motor (1, 21) and the horn (4, 24), the outer wall of the horn being arranged opposite an acoustic opening of the housing, and the space between the inner wall of the housing and the inner wall of the horn defines a cavity that contains a fluid.

Abstract: An acoustic antenna requiring the fewest possible number of assembly operations, which operations can be easily automated. The acoustic antenna includes an array of elementary transducers (15), each elementary transducer including, between a counterweight (10) and a horn (9), at least one ceramic (8), all the elementary transducers being mounted on a common printed circuit (7, 16) for electrical connection between the transducers and for positioning the transducers relative to one another, and at least one connector (26, 27) fixed to this printed circuit, each of the transducers being mounted in such a way that the printed circuit is clamped between the ceramic(s) thereof and the counterweight thereof.

Abstract: Frontal sonar for observing the seafloor, characterized in that it includes: elements for insonifying a seafloor area divided into M sectors, able to perform a characteristic insonification of each sector of the area during an operation recurrence of the sonar; and receiving elements including a physical antenna consisting of an array of K transducers, the antenna being lacunar and thus ambiguous, so that it defines N image lobes, and in that each of the characteristically insonified sector is associated with a single image lobe defined by the antenna, so that the antenna ambiguity is removed.