Strangely shaped drops playing the “game of life“
In 1831 Michael Faraday discovered that a liquid bath can present waves on its surface when it is subjected to vertical oscillation. Until now this has been performed in liquids confined in containers of different fixed shapes. We have performed the Faraday experience in an alcohol drop floating on an oil bath. The interplay of the waves with the border of the drop generates two behaviors. In the first one, the drop shape co-evolves with the waves to reach an equilibrium and
becomes elliptical or square , recalling the self-tuning of oscillators as in optical laser cavities and micro-cavities. In the second the drop is extended by the waves, it buckles and breaks in fragments with archetypical shapes: snakes, croissants, horseshoes or rings. These fragments self-propagate, rotate, collide, destroy each other, reorganize etc…Their interplay on the liquid bath recalls the famous Conway's mathematical “game of life“. These behaviors show how a beautiful complex collective behavior can emerge in a very simple experiment.
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LU12992
Microfluidic Assembly Lines
Microflouidic technology has revolutionized the control of flows at small scales giving rise to new possibilities for assembling complex structures on the microscale. We analyze different possible algorithms for assembling arbitrary structures, and demonstrate that a sequential assembly algorithm can manufacture arbitrary 3D structures from identical constituents. We illustrate the algorithm by showing that a modifed Hele-Shaw cell with 7 controlled flowrates can be designed to construct the entire English alphabet from particles that irreversibly stick to each other.
