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How can we store more energy from the sun and the wind? Image copyright Solar Reserve It could be a scene from a science fiction movie. Deep in the Nevada desert, thousands of mirrors arrayed in concentric circles face the sky, lit up by the sun. All this reflected sunshine is directed to the top of a 640 ft (195m) tower standing in their midst. It's an innovative power plant generating electricity, but not in a way you might expect. And it can carry on doing so even after the sun goes down. How? The concentrated light heats up liquid salt pumped to the top of the tower - the temperature reaches 566C (1,050F) - and this heat is then used to make steam to power an electricity generator in another part of the plant.
"The issue with solar traditionally is it is an intermittent power source - you can only produce electricity when the sun is shining," explains Kevin Smith, whose company Solar Reserve built the Crescent Dunes plant. Growing market Image copyright Getty Images Power to the people 'Three tennis courts' Green but unclean? Image copyright Aquion. JavaScript Particle System Sandbox. Graphene shows promise for bulletproof armour. 28 November 2014Last updated at 05:44 ET By Paul Rincon Science editor, BBC News website Caught in the net: Microbullets were fired at sheets of graphene The "wonder material" graphene could be used to make bulletproof armour. US researchers carried out miniature ballistic tests by firing tiny silica spheres at sheets of graphene. In Science magazine, they report that atom-thick layers of this material can be stronger than steel when it comes to absorbing impacts.
Graphene consists of a sheet of single atoms arranged in a honeycomb structure. It is thin, strong, flexible and electrically conductive, and has the potential to transform electronics as well as other technologies. Jae-Hwang Lee from the University of Massachusetts in Amherst and colleagues used lasers to observe the silica "microbullets" as they penetrated sheets of graphene between 10 and 100 layers thick.
They compared the kinetic energy of the spheres before and after they pierced the graphene sheets. Einstein Was Wrong 1 of 4.
Astronomija un kosmoloģija. Kodoli. Kvanti. Elektromagnētisms. Iekārtas. Optika. MinutePhysics. Mehānika.