By Larry Dignan
Posting in Energy
In 1986, two IBM scientists---J. Georg Bednorz and K. Alex Muller---discovered superconductivity in an oxide material at -397 deg F. That temperature was 50 percent higher than the previous mark.
High-temperature superconductivity is turning 25 years old.
In 1986, two IBM scientists---J. Georg Bednorz and K. Alex Muller---discovered superconductivity in an oxide material at -397 deg F. That temperature was 50 percent higher than the previous mark. Superconductivity was discovered in 1911 by Heike Kamerlingh Onnes, a Dutch physicist. Onnes discovered that superconductivity occurs when metals like tin and lead are cooled to absolute zero (-459.67 deg F).
Just a year after that discovery, Bednorz and Muller were awarded the Nobel Prize for Physics. Indeed, the high-temp superconductivity discovery had applications in measurement technology, electrotechnology and microelectronics.
Applications today include:
- Magnetic-resonance imaging (MRI) scanners.
- American Superconductor is using high-temp superconductor wire for energy efficient cables (right). These lines are being used in the Tres Amigas Project, which connects three power grids to create a renewable energy market.
- Magnetic Levitating Trains, which are being tested in Asia. These trains use magnets to levitate above the steel rails.
Apr 18, 2011
I'm trying to self-teach on superconductors in my not so copious spare time. I've read about high magnetic fields from the current causing the loss of superconductivity at a certain threshold; but I'm not clear enough on how that happens to be able to explain it to others. The highest temperature superconductor I've been able to uncover is palladium hydride (PdH) that's been saturated with hydrogen. It becomes a superconductor at 260K, far above the temperature of liquid nitrogen (77K), so cooling it is simple and relatively cheap. Now I figure a disk made of palladium hydride and cooled to superductivity would work perfectly for testing the Droscher-Hauser gravito-magnetic drive model. Unfortunately, the damn stuff costs as much as gold; so getting 300Kg of the stuff to build a drive prototype is prohibitively high for a backyard tinkerer, and even for low budget colleges. Pd107 would work, and ought to be cheaper, even though it's mildly radioactive; but the nuclear industry government controllers (and the Anti-Nuclear Eco-freaks) would never go for it.
The problem isn't the current, it's the magnetic field generated by the current. In the presence of a strong magnetic field, the superconducting property breaks down.
I don't think you understand how superconductivity works... It doesn't matter how much current is carried, it doesn't affect the temperature of the conductor at all. The only problem is keeping the entire cable cool enough.
The simple truth is that high-temp superconductivity just never delivered the huge leaps in energy savings that were promised. It has a hard time maintaining its superconductivity when carrying large currents. Even the 5 GW DC superconductive lines used in the Tres Amigas Project are short haul, only a few miles in length.