SIEVES made of sound could one day ramp up the power of nano-manufacturing and cell therapy.
Ultrasound waves have been used before to levitate and mix small objects or droplets. A team led by of the Shenzhen Institutes of Advanced Technology in China has now used sound wave pressure to lift and sort many objects at once.
The team etched a thin brass plate and placed it in a tank of water. Ultrasound blasted from above sends acoustic waves through the water that cause the plate to resonate with the surface below. The resulting sound pressure lifts objects placed in the tank according to size and density (Physical Review Applied, ).
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The team sorted small glass beads from larger ones and glass beads from tin. Zheng says the device could be tuned to sort a range of nano-scale objects.
This article appeared in print under the headline 鈥淐hoose what floats with a sound sieve鈥�