A gas turbine engine includes an airfoil and a deicing system. The airfoil radially extends from a hub towards a case disposed about a central longitudinal axis of the gas turbine engine. The deicing system includes an acoustic driver assembly arranged to apply acoustic energy to the airfoil to excite a predetermined vibratory mode of the airfoil.

An improved pinpoint alarm system for sound localization comprising a voltage regulator logic controller, and sounder comprising a piezoelectric plate mounted in a Helmholtz generator, the logic controller configured and programmed to generate repetitively a pseudorandom frequency within a predetermined range of frequencies based on the peak or resonant frequencies of the sounder to directly or indirectly drive the sounder. The pinpoint alarm system can be used in a variety of applications, including vehicles and tracking devices.

A method and circuit for controlling a multi-use horn by a bus are disclosed. The circuit comprises a bus signal receiving and transmitting unit used for receiving and transmitting a horn control instruction from a vehicle-mounted computer controller by the bus, a control unit used for generating a horn sounding signal adapting to a current scene according to the horn control instruction, and a horn sounding unit used for making sounds according to the horn sounding signal. By adoption of the method and circuit, the horn is connected to the vehicle-mounted computer controller by the bus and is controlled by the vehicle-mounted computer controller to make sounds, and thus, sound requirements for various horns for different uses on vehicles and engineering machines are met.

An ultrasonic transmitter. The ultrasonic transmitter includes a first enclosure, a second enclosure, a piezoelectric transducer, a first piston, and a second piston. The first enclosure has an opening for directing an output of the ultrasonic transmitter in a first direction and a wall opposite the opening. The second enclosure has a first opening aligned in the first direction and a second opening opposite the first opening. The second enclosure is positioned in the first enclosure with the second opening directed toward the wall. The piezoelectric transducer is positioned in the second enclosure and movable relative to the first enclosure. When an ultrasonic electric signal is applied to the piezoelectric transducer, the piezoelectric transducer expands and contracts pulsing the first and second pistons to produce ultrasonic sound waves from the first and second openings which combine and our output by the ultrasonic transmitter.

An ultrasonic transmitter. The ultrasonic transmitter includes a first enclosure, a second enclosure, a piezoelectric transducer, a first piston, and a second piston. The first enclosure has an opening for directing an output of the ultrasonic transmitter in a first direction and a wall opposite the opening. The second enclosure has a first opening aligned in the first direction and a second opening opposite the first opening. The second enclosure is positioned in the first enclosure with the second opening directed toward the wall. The piezoelectric transducer is positioned in the second enclosure and movable relative to the first enclosure. When an ultrasonic electric signal is applied to the piezoelectric transducer, the piezoelectric transducer expands and contracts pulsing the first and second pistons to produce ultrasonic sound waves from the first and second openings which combine and our output by the ultrasonic transmitter.

An acoustically resonating medium has one or more nodes and anti-nodes. Insulating a first side of a resonating medium at a node from ambient air and exposing the opposite second side of the resonating medium at the node to ambient air results in thrust in the direction of the first side. Insulating the second side of a resonating medium at an anti-node from ambient air and exposing the first side of the medium at the anti-node to ambient air also results in thrust in the direction of the first side.

An acoustically resonating medium has one or more nodes and anti-nodes. Insulating a first side of a resonating medium at a node from ambient air and exposing the opposite second side of the resonating medium at the node to ambient air results in thrust in the direction of the first side. Insulating the second side of a resonating medium at an anti-node from ambient air and exposing the first side of the medium at the anti-node to ambient air also results in thrust in the direction of the first side.

A device for detecting contact with and/or an approach toward a motor vehicle. The device includes a vibration generator, including a first electromechanical transducer configured to be mounted on an external element of the motor vehicle, and an electrical signal generator that delivers, to the first electromechanical transducer, an electrical signal oscillating at an excitation frequency; a rechargeable energy storage device, for supplying power to the electrical signal generator; and a vibration sensor, consisting of a second electromechanical transducer configured to be mounted on the external element of the motor vehicle. An output of the vibration sensor is connected to the rechargeable energy storage device, such that at least part of the electrical response signal recharges the rechargeable energy storage device.

The present invention relates to an ultrasonic generator for repelling harmful animals. The invention comprises a columnar ultrasonic wave generating body 18 which has a piezoelectric element 16 and a connecting body 22 and a smaller-diameter connecting body 24 each having a reduced diameter, a diaphragm 28 which is in the form of a speaker horn, and a connecting rod 26 which extends from the ultrasonic wave generating body 18 and connects and fixes the diaphragm 28 to an end thereof. The thickness of the diaphragm 28 gradually decreases from the base 34 connected to the connecting rod 26 toward an outer edge of the diaphragm 28 and one or more undulated portions 36 are formed concentrically on the front face of the diaphragm.

The present invention relates to an ultrasonic generator for repelling harmful animals. The invention comprises a columnar ultrasonic wave generating body 18 which has a piezoelectric element 16 and a connecting body 22 and a smaller-diameter connecting body 24 each having a reduced diameter, a diaphragm 28 which is in the form of a speaker horn, and a connecting rod 26 which extends from the ultrasonic wave generating body 18 and connects and fixes the diaphragm 28 to an end thereof. The thickness of the diaphragm 28 gradually decreases from the base 34 connected to the connecting rod 26 toward an outer edge of the diaphragm 28 and one or more undulated portions 36 are formed concentrically on the front face of the diaphragm.