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Submission + - Professors claim passive cooling breakthrough via plastic film (economist.com)

Submitted by charlesj68
charlesj68 writes: An article in the Economist discusses the development of a plastic film by two professors at the University of Colorado in Boulder that provides a passive cooling effect. The film contains embedded glass beads that absorb and emit infrared in a wavelength that is not blocked by the atmosphere. Combining this with half-silvering to keep the sun from being the source of infrared absorption on the part of the beads, and you have way of pumping heat at a claimed rate of 93 watts per square meter.
Actual paper in Science: http://science.sciencemag.org/...
Original research by others in Nature: http://www.nature.com/nature/j...

Submission + - Scientists Finally Turn Hydrogen Into a Metal, Ending a 80-Year Quest (arstechnica.com)

Submitted by Anonymous Coward
An anonymous reader writes: In 1935, scientists predicted that the simplest element, hydrogen, could also become metallic under pressure, and they calculated that it would take 25 GigaPascals to force this transition (each Gigapascal is about 10,000 atmospheres of pressure). That estimate, in the words of the people who have finally made metallic hydrogen, "was way off." It took until last year for us to reach pressures where the normal form of hydrogen started breaking down into individual atoms—at 380 GigaPascals. Now, a pair of Harvard researchers has upped the pressure quite a bit more, and they have finally made hydrogen into a metal. All of these high-pressure studies rely on what are called diamond anvils. This hardware places small samples between two diamonds, which are hard enough to stand up to extreme pressure. As the diamonds are forced together, the pressure keeps going up. Current calculations suggested that metallic hydrogen might require just a slight boost in pressure from the earlier work, at pressures as low as 400 GigaPascals. But the researchers behind the new work, Ranga Dias and Isaac Silvera, discovered it needed quite a bit more than that. In making that discovery, they also came to a separate realization: normal diamonds weren't up to the task. "Diamond failure," they note, "is the principal limitation for achieving the required pressures to observe SMH," where SMH means "solid metallic hydrogen" rather than "shaking my head." The team came up with some ideas about what might be causing the diamonds to fail and corrected them. One possibility was surface defects, so they etched all diamonds down by five microns to eliminate these. Another problem may be that hydrogen under pressure could be forced into the diamond itself, weakening it. So they cooled the hydrogen to slow diffusion and added material to the anvil that absorbed free hydrogen. Shining lasers through the diamond seemed to trigger failures, so they switched to other sources of light to probe the sample. After loading the sample and cranking up the pressure (literally—they turned a handcrank), they witnessed hydrogen's breakdown at high pressure, which converted it from a clear sample to a black substance, as had been described previously. But then, somewhere between 465 and 495 GigaPascals, the sample turned reflective, a key feature of metals

Comment Signing for authentication? (Score 1) 229

Beyond the encryption issue addressed in this article, the inclusion of cryptographic features in cameras could offer an authentication feature. Hash the image in its RAW format, sign the hash and store it in the meta data. Do the same thing for the "thumbnail" JPGs that some cameras offer. Now you could tie a given image to a given camera and know that it had not been modified. Of course each camera would need to have its own key pair, and the manufacturer would have to warehouse the private keys and provide the validation service that verified an image was signed by a particular camera ... And there are lots of situations that tying an image to a given camera might not be beneficial. Probably too much work ...

Comment Re:development environment? (Score 1) 74

by charlesj68 (#52506307) Attached to: Assembly Code That Took America to the Moon Now Published On GitHub

My Dad worked on the Ranging Radar for the Lunar Excursion Module, so I've heard some stories.

Data input was punched cards (duh).

Tests included sticking a unit on the front of a missile and launching across White Sands Missile Range, then comparing the telemetry data returned with a known track mapped across a digitized re-creation of the range. Along the way they discovered the errors in the digitization when the results began claiming that the missile was travelling underground.

One of his research projects was to work out how to apply a new-fangled algorithm to the problem, Fast Fourier Transforms.

Comment Great fun! (Score 2) 234

by charlesj68 (#50310725) Attached to: California Fights Drought With 96 Million "Shade Balls"
In other news, thousands of Golden Retrievers have been observed hitch-hiking to Los Angeles to participate in an event described by one traveller as, "a canine Burning Man festival". "It's like somes guy just kept throwing balls and throwing balls, but der was no dog to go get 'em," said Max, a 7-year-old neutor from Chicago.

Comment Re:And the advantage of this is? (Score 1) 630

by charlesj68 (#46708651) Attached to: Navy Debuts New Railgun That Launches Shells at Mach 7

Imagine a shell that can adjust it's flight path, even slightly, which means you can fire in the general direction you want, then fine tune the aim in flight. (I assume they don't do that now..)

They don't, and even a railgun projectile probably won't either - because the force required to effect a significant change in trajectory (especially in azimuth) is simply too great.

M712 Copperhead

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