Monthly Archives: December 2013

Phase Change Comes from Within

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Engineer Designs Mug to Keep Coffee Temperature Just Right

A material (possibly paraffin) that melts/solidifies at the right temperature, so the liquid stays warm for an extended period of time. Reminiscent of Coffee Joulies. Which don’t seem to work as well as advertised, especially in an open ceramic mug. A test with lids in place shows better performance. This mug has a vacuum insulation layer and a lid, but caveat emptor. Though the physics behind the concept is sound.

The concept of a “phase-change” coffee mug to keep beverages warm was patented in the 1960s, but never made it to the marketplace due to manufacturing difficulties. But Maxwell happened to meet an engineer named Dean Verhoeven who had already solved the manufacturing problem. Dean and Maxwell teamed up and Joeveo was born

Their kickstarter closes on Jan 1, with delivery slated for next summer, so not a last-minute gift idea for this year, but perhaps an early shopping idea for next, even if delivery gets delayed a little.

You Usually Don't Get Condensation When it's This Warm

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Bose-Einstein Condensate Made at Room Temperature for First Time

[R]esearchers at IBM’s Binnig and Rohrer Nano Center have been able to achieve the BEC at room temperature using a specially developed polymer, a laser, and some mirrors.

Sounds vaguely McGuyver-ish. I’m sure duct tape was involved somewhere. Duct tape is always involved.

Anyway, I’m not sure how this is useful yet, given that the BEC only lasts for a few picoseconds. Atom laser and optical switch sound like boiler-plate responses. (Similar to how other atomic physics efforts are hyped to be great for making new types of atomic clocks, but that rarely ends up happening) I would be interested in knowing how they determined that they had a BEC in the first place.

A Hot Mess

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Chernobyl’s Hot Mess, “the Elephant’s Foot,” Is Still Lethal

By the fall of 1986, the emergency crews fighting to contain the nuclear disaster at Chernobyl made it into a steam corridor beneath failed reactor Number 4. Inside this chamber they found black lava that had oozed straight from the core. The most famous formation was a solid flow that their radiation sensors firmly told them not to approach. With cameras pushed in from around a corner, the workers dubbed the dimly lit mass “the Elephant’s Foot.” According to readings taken at the time, the still hot portion of molten core put out enough radiation to give a lethal dose in 300 seconds.

The Elephant’s Foot could be the most dangerous piece of waste in the world.

via fine structure

183

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The US Naval Observatory was established on Dec 6, 1830, as the Depot of Charts and Instruments under the command of LT Louis Goldsborough. Its function was to maintain, repair and rate navigational instruments and had an annual budget of $330. Its mission expanded in 1842 to include its function as the national observatory, and moved to its current location in 1893. (Back then, it was out in the boondocks and away from the lights of the city.)

Navigational instruments include chronometers, necessary for determining longitude, which is why the Observatory maintains time for the military.

Happy 183rd birthday.

Lead, Rather than a Duck.

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Since we are not asking “What else floats in water?”

Use of ancient lead in modern physics experiments ignites debate

Unfortunately the story really doesn’t lay out the case for why ancient lead ballast falls into the category of “cultural heritage artifact” or why more than a small fraction of it would need to be preserved for study. Newly mined lead is contaminated with Pb-210, which has a half-life of about 22 years and is present because it’s in the decay chain of U-238. So Pb that’s been around for several hundred years (especially under water where it would better shielded against any kind of activation reaction) has been separated from the source of the unstable isotope that produces it (ultimately U-238, but realistically Ra-226, which is the “most recent” previous step along the decay chain with a half-life longer than a year) is more useful for shielding detectors, as it has essentially no sources of radiation that might cause spurious readings.