École numérique

Material World Wind turbines, electric vehicles, light-emitting diodes, flat-screen displays, and solar panels all rely on elements that are mined and refined in just a few countries and traded in small quantities. Demand for many of these elements is expected to grow rapidly as these technologies become more commonly used, and impending supply constraints could hold back their growth. As the wind-power industry expands, for example, demand for the rare-earth element neodymium, a crucial ingredient in the high-strength magnets used in wind turbines, is projected to outstrip supply by 16 percent in 2014. (China controls 97 percent of global production of rare-earth elements.) About Want to let people share and use your photographs, but not allow companies to sell them?Looking for access to course materials from the world’s top universities?Want to encourage readers to re-publish your blog posts, as long as they give you credit?

Four Questions with Seth Priebatsch, Creator of LevelUp If you’ve grabbed a meal downtown or off a food truck and didn’t pay with cash or a card, there’s a good chance Seth Priebatsch had a hand in that purchase. Seth’s invention, LevelUp, has changed the way we pay for things. I asked him how it all works and the future of paying for stuff with our phones.