Word: trained
(lookup in dictionary)
(lookup stats)
Dates: during 1980-1989
Sort By: most recent first
(reverse)
...point it liquefies. But the process is expensive and requires considerable energy. Furthermore, unless the liquid helium is tightly sealed in a heavily insulated container, it quickly warms and vaporizes away. Thus the practical use of superconductors has been limited to a few devices -- an experimental Japanese magnetically levitated train, a few giant particle accelerators and medicine's magnetic-resonance imaging machines -- that operate with intense magnetic fields...
That was in 1961, near the beginning of what those who know all the verses to Freight Train now call, with the rueful irony of survivors, the "great folk-music scare of the '60s." For the rest of the decade and part of the '70s too, Rush spent most of his time on the road, as he recalls now, playing concerts and club gigs, getting a lavender tan from stage lights, finding his moments of repose watching the mysterious turning, turning of airport carrousels, living a life that made more money than sense. A song he wrote in those cockerel...
...long ago as 1979 an unmanned Japan Railways Group prototype fitted with low-temperature superconducting electromagnets hit 321 m.p.h. on a test track; a version carrying three passengers made it to 249 m.p.h. earlier this year. That beats any conventional rival, including Japan's celebrated bullet train, which goes as fast as 149 m.p.h., and the French TGV, which provides the world's fastest regularly scheduled rail service, at speeds of up to 186 m.p.h...
...principle behind the maglev is simple: opposite magnetic poles attract each other; like poles repel. In Japan's version, eight superconducting electromagnets are built into the sides of each train car, and thousands of metal coils are set into the floor of the guideway. When the train is in motion, the electromagnets on the train induce electric currents in the guideway coils, which then themselves become electromagnets. As power is increased, the opposing sets of magnets repel each other and lift the train into the air. Two other rows of electromagnets, one on each wall of the U- shaped guideway...
...planning the train, Japanese engineers chose superconducting magnets ( because for a given input of electricity they generate more intense magnetic fields -- and thus greater lifting and propulsion power -- than conventional electromagnets. The drawback: the liquid-helium coolant needed for the superconducting magnets is expensive, and a heavy compressor is required in each coach to reliquefy the evaporating helium. That is why maglev engineers are excited by the idea of the new high-temperature superconductors, which would use considerably less expensive liquid nitrogen as a coolant and require far smaller compressors. The developments of the past few months, says Research Chief...