The trick is to tune the crystal, by modifying the details of pattern, so that as much of the emittedenergy as possible is at the frequency most efficiently captured by indium gallium arsenide.
Several days ago the Federal Communications Commission announced that it would undertake a re-examination of the standards limiting how much radiofrequency (RF) energy can be emitted by cellular telephones.
Major fashion brands also have an obligation to dramatically reduce the amount of water and energy used and waste emitted in making and selling their clothes, as well as to offer consumers more stylish products that are made out of recycled and eco-friendly materials.
"Desalination requires a lot of power ... we estimate that about four tonnes of carbon are emitted per million gallons of freshwater produced here, " he says, with reference to the energy-intensive process of removing salt from seawater (see factbox).
The group measured the vibrations emitted in the chests of pigs and sheep during surgeries, and then used those calculations to estimate how much electrical energy would be generated by the harvester.