Cool party trick: Van Arsdell's coffee cup stirling engine kit.
With the potential to achieve much higher efficiencies and run cleaner than internal combustion engines, Stirling engines—which use an external heat source to perform work—have long been a source of fascination for engineers. In fact, when Aeronautical Engineer Brent Van Arsdell first saw a friend of his running a Stirling engine on a bowlful of ice cubes, his first thought was, "I've got to build one myself." Since then, he has come up with ten different engine designs and "probably assembled a couple thousand engines by hand." And, he has made it his mission to educate the world about this unique engine design. Plus, he gets to show people the Ideal Gas Law in action! His company, American Stirling ( www.stirlingengine.com), develops Stirling engines for the educational market as well as demonstration kits. His most popular item: The MM-5 Coffee Cup Engine Kit, which includes all the components needed to build an engine that operates at 250 rpm on a Starbucks' espresso or 100 rpm on a bowl of Cherry Garcia ice cream. It's a great party trick, he says. As far as practical use, Van Arsdell says that his engines put out only a tiny amount of power—anywhere from 2 to 30 mW. The problem, says Van Arsdell: It's difficult to build a Stirling engine that puts out a high power density, and the cost would be prohibitive for many mainstream applications. In fact, if you know of a small Stirling engine that is cost-competitive with gas or diesel engines on a per kW-basis, Van Arsdell would like to hear from you at firstname.lastname@example.org.
Samsung's Galaxy line of smartphones used to fare quite well in the repairability department, but last year's flagship S5 model took a tumble, scoring a meh-inducing 5/10. Will the newly redesigned S6 lead us back into star-studded territory, or will we sink further into the depths of a repairability black hole?
In 2003, the world contained just over 500 million Internet-connected devices. By 2010, this figure had risen to 12.5 billion connected objects, almost six devices per individual with access to the Internet. Now, as we move into 2015, the number of connected 'things' is expected to reach 25 billion, ultimately edging toward 50 billion by the end of the decade.
NASA engineer Brian Trease studied abroad in Japan as a high school student and used to fold fast-food wrappers into cranes using origami techniques he learned in library books. Inspired by this, he began to imagine that origami could be applied to building spacecraft components, particularly solar panels that could one day send solar power from space to be used on earth.
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