Scientists at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) demonstrated how particles, floating on top of a glycerin-water solution, synchronize in response to acoustic waves blasted from a computer speaker.
The study, published today (Monday, June 19) in the journal Nature Materials, could help address fundamental questions about energy dissipation and how it allows living and nonliving systems to adapt to their environment when they are out of thermodynamic equilibrium.
[...] "We show that individually 'dumb' particles can self-organize far from equilibrium by dissipating energy and emerge with a collective trait that is dynamically adaptive to and reflective of their environment," said study co-lead author Chad Ropp, a postdoctoral researcher in Zhang's group. "In this case, the particles followed the 'beat' of a sound wave generated from a computer speaker."
Notably, after the researchers intentionally broke up the particle party, the pieces would reassemble, showing a capacity to self-heal.
Ropp noted that this work could eventually lead to a wide variety of "smart" applications, such as adaptive camouflage that responds to sound and light waves, or blank-slate materials whose properties are written on demand by externally controlled drives.
[...] As the sound waves traveled at a frequency of 4 kilohertz, the scattering particles moved along at about 1 centimeter per minute. Within 10 minutes, the collective pattern of the particles emerged, where the distance between the particles was surprisingly non-uniform. The researchers found that the self-assembled particles exhibited a phononic bandgap -- a frequency range in which acoustic waves cannot pass -- whose edge was inextricably linked, or "enslaved," to the 4 kHz input.
Journal Reference:
Nicolas Bachelard, Chad Ropp, Marc Dubois, Rongkuo Zhao, Yuan Wang, Xiang Zhang. Emergence of an enslaved phononic bandgap in a non-equilibrium pseudo-crystal. Nature Materials, 2017; DOI: 10.1038/nmat4920
(Score: 0) by Anonymous Coward on Wednesday June 21 2017, @11:45PM
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