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Hur fjärilar överlever påverkan av regndroppar

Källa: John Munson / Cornell University.

En intressant kort video. Insektsvingar (och andra naturliga objekt som fågelfjädrar och växtblad) är superhydrofoba.

In analyzing the film, they found that when a drop hits the surface, it ripples and spreads. A nanoscale wax layer repels the water, while larger microscale bumps on the surface creates holes in the spreading raindrop.
    “Consider the micro-bumps as needles,” Jung said. If one dropped a balloon onto these needles, he said, “then this balloon would break into smaller pieces. So the same thing happens as the raindrop hits and spreads.”
    This shattering action reduces the amount of time the drop is in contact with the surface, which limits momentum and lowers the impact force on a delicate wing or leaf. It also reduces heat transfer from a cold drop. This is important because the muscles of an insect wing, for example, need to be warm enough to fly.

Forskning av Sunghwan “Sunny” Jung tittar på hur vattendroppar studsar av “superhydrofoba” ytor som insektsvingar, fågelfjädrar och växtblad.
    PNAS: How a raindrop gets shattered on biological surfaces.
    Wikipedia: Hydrofob interaktion.


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