By the 1970s, the company split its work evenly between underwater applications ( oceanography, military scanning sonars and anti-submarine warfare developments ) and electro-acoustic systems, including ultrasonic transducers for in-air applications, intrusion alarms, motion detectors, remote-control proximity indicators, and even the first automatic scoring system for bowling.
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Another function of the ultrasonic horn is to efficiently transfer the acoustic energy from the ultrasonic transducer into the treated media, which may be solid ( for example, in ultrasonic welding, ultrasonic cutting or ultrasonic soldering ) or liquid ( for example, in ultrasonic spraying or cell disruption ).
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Typically, external excitation is performed with optical devices such as photographic flashes ( for heat pulsed stimulation ) or halogen lamps ( for periodic heating ), whereas internal excitation can be achieved by means of mechanical oscillations, with a sonic or ultrasonic transducer for both burst and amplitude modulated stimulation.
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Using ultrasonic transducers, the flow meter can measure the average velocity along the path of an emitted beam of ultrasound, by averaging the difference in measured transit time between the pulses of ultrasound propagating into and against the direction of the flow or by measuring the frequency shift from the Doppler effect.
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An "'ultrasonic horn "'( also known as "'acoustic horn "', "'sonotrode "', "'acoustic waveguide "', "'ultrasonic probe "') is a tapering metal bar commonly used for augmenting the oscillation displacement amplitude provided by an ultrasonic transducer operating at the low end of the ultrasonic frequency spectrum ( commonly between 15 and 100 kHz ).
