Monday, August 31, 2009

Cloak that Redirects Seismic Waves from Buildings

According to scientists from the University of Liverpool they carried out a research that showed it is quite possible to create an invisibility cloak that would protect different constructions from earthquakes.
It is worth mentioning that seismic waves generated by earthquakes include body and surface waves, the former traveling through the earth and the latter traveling across it. Researcher's latest invention is able to manage the surface waves that lead to great destructions as a result of earthquakes.
The technology was elaborated by Sebastien Guenneau, from the University's Department of Mathematics along with Stefan Enoch and Mohamed Farhat from the Fresnel Institute (CNRS) in Marseilles, France.
The researchers were able to 'tune' their latest invention to the conflicting frequencies of incoming seismic waves, being able to redirect waves of different frequencies. The new technology makes use of concentric rings of plastic that are fixed to the Earth's surface to redirect surface waves.
"For each small frequency range, there is a pair of rings which does most of the work and these move about a lot - bending up and down - when they are hit by a wave at their frequency. The waves are then directed outside the cloak where they return to their previous size," explain scientists. They say that the waves are not reflected, but carry on traveling behind the cloak without lowering the level of their intensity. Thus researcher's latest invention transfers the risk from one area to another, but it does not fully eliminate it.
"The challenge now is to turn our theories into real applications that can save lives - small scale experiments are underway," researchers say. link....

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