Slashdot Mirror
Scientists Accidentally Blow Up Their Lab With Strongest Indoor Magnetic Field Ever (vice.com)
An anonymous reader quotes a report from Motherboard: Earlier this year, researchers at the University of Tokyo accidentally created the strongest controllable magnetic field in history and blew the doors of their lab in the process. As detailed in a paper recently published in the Review of Scientific Instruments, the researchers produced the magnetic field to test the material properties of a new generator system. They were expecting to reach peak magnetic field intensities of around 700 Teslas, but the machine instead produced a peak of 1,200 Teslas. (For the sake of comparison, a refrigerator magnet has about 0.01 Tesla)
In both the Japanese and Russian experiments, the magnetic fields were generated using a technique called electromagnetic flux-compression. This technique causes a brief spike in the strength of the magnetic field by rapidly "squeezing" it to a smaller size. [...] Instead of using TNT to generate their magnetic field, the Japanese researchers dumped a massive amount of energy -- 3.2 megajoules -- into the generator to cause a weak magnetic field produced by a small coil to rapidly compress at a speed of about 20,000 miles per hour. This involves feeding 4 million amps of current through the generator, which is several thousand times more than a lightning bolt. When this coil is compressed as small as it will go, it bounces back. This produces a powerful shockwave that destroyed the coil and much of the generator. To protect themselves from the shockwave, the Japanese researchers built an iron cage for the generator. However they only built it to withstand about 700 Teslas, so the shockwave from the 1,200 Teslas ended up blowing out the door to the enclosure. While this is the strongest magnetic filed ever generated in a controlled, indoor environment, the strongest magnetic field produced in history belongs to some Russian researchers who created a 2,800 Tesla magnetic field in 2001.
In both the Japanese and Russian experiments, the magnetic fields were generated using a technique called electromagnetic flux-compression. This technique causes a brief spike in the strength of the magnetic field by rapidly "squeezing" it to a smaller size. [...] Instead of using TNT to generate their magnetic field, the Japanese researchers dumped a massive amount of energy -- 3.2 megajoules -- into the generator to cause a weak magnetic field produced by a small coil to rapidly compress at a speed of about 20,000 miles per hour. This involves feeding 4 million amps of current through the generator, which is several thousand times more than a lightning bolt. When this coil is compressed as small as it will go, it bounces back. This produces a powerful shockwave that destroyed the coil and much of the generator. To protect themselves from the shockwave, the Japanese researchers built an iron cage for the generator. However they only built it to withstand about 700 Teslas, so the shockwave from the 1,200 Teslas ended up blowing out the door to the enclosure. While this is the strongest magnetic filed ever generated in a controlled, indoor environment, the strongest magnetic field produced in history belongs to some Russian researchers who created a 2,800 Tesla magnetic field in 2001.
From the Headline to the Article:
Headline: "Blew up their lab"
Summary: "Blew the doors off of their lab"
Article: "Blew the door off of the generator enclosure"
Video: "There was a small fire in the fixture that lasted a few seconds, but otherwise nothing happened"
Then the Japanese brought us thoughtfully engineered vehicles which were lighter, safer, more reliable and less expensive.
Nice myth. Did you know that a 2018 Toyota Camry weighs pretty much the same as a 1951 Chevy Malibu?
It's not a myth. When you recycle steel, it gets harder. You can put carbon back into it to make it softer, but that costs money. American cars of the 1950s were made out of mild steel. That steel eventually got recycled and shipped to Japan. Then the Japanese didn't add more carbon to it — instead, they designed vehicles around the materials. More straight lines, more sharp edges. And in a monocoque design (aka "unit body", aka "unibody")* the additional stiffness was a boon instead of a bane. It meant that you could get just as much strength with a lighter (but harder) grade of steel. It wasn't until Lee Iacocca's Chrysler K-Cars that Americans built cars like the Japanese did, and those lightweight and thus fuel-efficient vehicles absolutely did affect the American automakers in the early 1970s.
This wasn't just restricted to the Americans, though. The rest of the non-Asian world was still building cars out of mostly mild steel. But, fast forward to 1978. Mercedes designs the W126, their first automobile made out of 100% high strength steel, which goes into production for the 1981 model year. This vehicle shaves hundreds of pounds off as compared to the predecessor, the W116. It also introduces the eurostyle we know today, with unit headlights which take capsules (though not in the USA, where we had misguidedly mandated sealed beams for safety) and with an integrated, flush-mount bumper cover for aerodynamics (but not in the USA, where we had perhaps more reasonably mandated 5-mph bumpers — in the US, the bumper sticks out considerably.) And automotive design was never the same. Everyone and their mom has since emulated the W126 to some degree, and in some models. For example, the original Lexus LS was a fairly shameless W126 copy.
The other notable thing that happened in 1978 was Mercedes-Benz's introduction of a four channel ABS system, designed and built by Bosch. While the W126 was to reduce unit body mass, ABS began the trend of increasing it with safety features. Mercedes made air bags and pyrotechnic pretensioners standard on the W126 in about 1986; they were available as options from the introduction in 1981. Today, ABS is actually standard equipment; in the EU it has been mandatory on passenger cars since 2004, and in the USA it was made mandatory as part of ESC in 2013.
Finally, the USA has been a leader in pushing crash safety standards. Both the NHTSA and the IIHS have their own crash safety tests that have been forcing automakers to add metal for the last couple of decades. Notably, rollover protection, side impact protection, and small offset crash protection have all substantially increased vehicle weight in the last number of years. As well, American cars are less American than ever. GM's most popular models have been designed in Australia, Chrysler's full-size sedan is just a cheap copy of a Mercedes E-Class, Ford has gone fully multinational and has abandoned all but their smallest and lightest vehicles...
TL;DR: Your comparison of a modern Japanese car to an American one of over sixty years ago is completely meaningless.
* Why are neither monocoque nor unibody in the Moz dict? Fail, fail.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
No, the 4M Amps is going to destroy the generator just fine without any explosives, the containment cage was to keep the explosion of the generator inside the room. When the cage failed under the 60% higher than expected field strength the explosion was no longer contained to the experiment and thus blew the doors off the lab.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.