Ice-proof coating for big structures relies on a ‘beautiful demonstration of mechanics’

Phys.org  April 25, 2019 The problem with the strategy to lower adhesion strength strategy is that the larger the sheet of ice, the more force is required. Researchers at the University of Michigan developed new coating which lowers the interfacial toughness (LIT). Surfaces with low LIT encourage cracks to form between ice and the surface. And unlike breaking an ice sheet’s surface adhesion, which requires tearing the entire sheet free, a crack only breaks the surface free along its leading edge. Once that crack starts, it can quickly spread across the entire iced surface, regardless of its size. Mathematically they […]

Researchers develop ‘acoustic metamaterial’ that cancels sound

Phys.org  March 7, 2019 Based on the premise that metamaterial needs to be shaped in such a way that it sends incoming sounds back to where they came from, researchers at Boston University calculated the dimensions and specifications that the metamaterial would need to have in order to interfere with the transmitted sound waves. Using the calculation they created a structure made of plastic that could silence sound from a loudspeaker. In tests they found that 94 percent of the sound emanating from the loudspeaker was imperceptible to the human ear. The shape of acoustic-silencing metamaterials is also completely customizable. […]