Liquid Mirror Telescopes Set For Magnetic Upgrade
Author: timothy
KentuckyFC writes "Liquid mirror telescopes start life as a puddle of mercury in a bowl. Set the bowl spinning and the mercury spreads out in a thin film giving the surface an almost perfect mirror finish. But these telescopes have two important limitations. First, they can only point straight up since tilting the mirror spills the mercury. And second, they cannot be made adaptive to correct for any blurring introduced by the Earth's atmosphere. But liquid mirror telescopes look set for an upgrade thanks to the work of a group of Canadian researchers. Their technique is to change the shape of the liquid mirror using powerful electromagnets. They use a ferromagnetic fluid of iron nanoparticles in oil instead of mercury which is too dense to be easily manipulated in this way. The work is just proof of principle at this stage but the idea is to use magnets to correct for the usual range of optical aberrations that telescopes have to deal with (abstract). And also to allow a liquid telescope to be tilted by using oil that is much more viscous than mercury and correcting any periodic deformation in the fluid that tilting might cause."

Read more of this story at Slashdot.

Subwoofer makes cornstarch dance
Author: Juan Aguilar

Filed under: misc hacks

People tend not to think about the non-Newtonian properties of foodstuffs, but we're glad at least one person did. When it comes to cornstarch, it's indeterminate viscosity when mixed with water made it the perfect solution for a pretty neat trick: making a liquid move in reaction to a subwoofer. The unique motion can be attributed to the physical properties of the solution: when enough force is applied quickly, it acts as a solid. Otherwise, it flows like a liquid. The erratic bouncing of the sound waves combined with a little tactile manipulation create varying degrees and speeds of applied pressure, which in turn create a mass of flowing shapes that almost appear to be alive. We've covered weird fluids before, but this is perhaps most similar to SnOil, a game that uses ferrofluids to achieve a similar result. SnOil, however, does not depend of vibrations to create shapes in the fluid, it uses small electromagnets and magnetically charges liquid instead. We love the ordered appearance of the SnOil unit, but the chaotic motion of the cornstarch and it's non-Newtonian properties make it appear almost otherworldly. We wonder how ferrofluids would react in a situation similar to the cornstarch above, since it would respond to both the vibration and the voice coil's magnetic field.[via Neatorama]Read | Permalink | Email this | Linking Blogs | Comments
Published: 2008-07-11 14:50:00

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Recycle old PCB components

Instructable to get you started on how to recycle old PCB components.

More: 'Crush and zap' recycles circuit boards more cleanly.

Motherboard PCB bracelet.

Procuring Electronic Components.

Procuring lowtech sensors and actuators.

Read more | Permalink | Comments | Read more articles in DIY Projects | Digg this!
Published: 2008-07-11 03:00:22

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Save up to 65% on Capacitors and Resistors
Author: mdubinko

Nope, not spam. You can now order electronic components from Amazon, advertised right on the front page for me. What can’t you get on Amazon? -m

Published: 2008-07-09 00:30:14

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Curly-Winged UAV Will Leech From Power Lines, Fly Forever [UAVs]
Author: John Herrman

The next version of the DevilRay unmanned aerial vehicle will feature the ability to dock to and recharge from power lines. Made by Defense Research Associates, the UAV uses down-curled wingtips to make such a low-speed maneuver possible. The four-foot wide, propeller-driven flying wing will use "inverse capped helix winglets" to take advantage of the wingtip wind vortexes that form during flight, providing stabilization in lieu of a tail.

To recharge, the DevilRay uses a combination of GPS and a magnometer to home in on power lines, and after it latches on it pulls electricity with electromagnetic induction. I guess if you've already got surveillance UAVs buzzing around the sky in a foreign country, you're probably not overly worried about stealing some power. It remains to be seen if this function will even work in practice, but if it does it would effectively provide infinite range. Testing of the power line piggybacking is scheduled for later this month. [Ares]

Published: 2008-07-07 20:20:00

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