Not so, if you use a pair of specialised ultrasonic transducer arrays to move the air instead! (Video, embedded below) Three banks of thrusters provide a 180 degree steerable net force Details are ...

[Lindsay] has a wonderful writeup about a new toy in the shop, an ultrasonic transducer. The 28kHz, 70W bolt-clamped Langevin transducer by itself is not much use, you need a power supply ...

Inventions by African Americans into the 21st century include everything from toys to physics to aerospace technology.

In this study, the research team developed an ultra-compact (1 mm²) transparent ultrasonic transducer capable of delivering high-resolution ultrasound and photoacoustic imaging simultaneously.