Archive for October 2009
You are browsing the archives of 2009 October.
You are browsing the archives of 2009 October.
Physicists at Brookhaven National Laboratory have identified a single layer responsible for one such material’s ability to become superconducting. The technique, described in the Oct. 30, 2009, issue of Science, could be used to engineer ultrathin films with “tunable” superconductivity for higher-efficiency electronic devices.
The thinner the material (and the higher its transition temperature to a superconductor), the greater its potential for applications where the superconductivity can be controlled by an external electric field. “This type of control is difficult to achieve with thicker films, because an electric field does not penetrate into metals more than a nanometer or so,” explains Brookhaven physicist and the group leader Ivan Bozovic.
To explore the limits of thinness, Bozovic’s group synthesized a series of films based on the high-temperature superconducting cuprates — materials that carry current with no energy loss when cooled below a certain transition temperature. Since zinc is known to suppress the superconductivity in these materials, the scientists systematically substituted a small amount of zinc into each of the copper-oxide layers. Any layer where the zinc’s presence had a suppressing effect would be clearly identified as essential to superconductivity in the film.
This discovery opens a path toward the fabrication of electronic devices with modulated, or tunable, superconducting properties which can be controlled by electric or magnetic fields.
On the heels of last week’s post about Nissan’s new plug-in hybrid, The Wall Street Journal reported that Nissan is the only car manufacturer out of Japan’s Big Three (Toyota, Honda, Nissan) that appears to be staking its future on full electric cars.
Unlike hybrids, full on electric cars will only travel as far as their battery packs allow. Honda and Toyota expressed skepticism over the technology, while Nissan is fully embracing it.
Critics of all-electric cars cite the high cost of batteries and the likely need for sizable government subsidies and incentives to make all-electric battery cars affordable. The lack of a wide network of battery-charging stations also could be an impediment.
Both Toyota and Honda say a full-electric car may work for certain consumers if they are willing to treat it as a town car with limited driving range. They also say the ultimate green car over the long run will be hydrogen fuel-cell vehicles, which they believe will be more efficient than full-electric battery cars. Fuel-cell cars would create their own electricity through a reaction between hydrogen and oxygen.
Carlos Ghosn, Nissan’s CEO, acknowledged his company was late to jump onto the hybrid bandwagon, and now plans to concentrate on battery-only cars. “We have had a period where we have had to catch up, but now we will exercise our technological power,” he said. “We are aiming for leadership in [electric vehicles].”
Nissan believes it has found a way to make electric cars, such as the Leaf, nearly as affordable as a gasoline-fueled compact cars. By selling it without its on-board battery pack, Nissan may lease the battery pack to the customer for an affordable month fee, among other means, its executives said.
But Nissan executives also stressed that government support is necessary to launch the Leaf, which it aims to sell world-wide in 2012.
“We are asking governments to cover [the investment] up to the point when we can reach volume momentum—this will take several years,” said Carlos Tavares, who heads Nissan’s Americas operations. Mr. Ghosn estimated that this would take three to four years.
According to The Idaho Statesman, Nuclear experts like the Idaho National Laboratory’s Dave Hill are confident as many as 10 reactors will be built in the next two decades.
“I think it’s pretty clear there will be a nuclear renaissance,” said Hill, the deputy INL director.
Right now it looks like none of the new reactors will go up at the lab or even in Idaho. But the future of the facility eastern Idahoans refer to simply as “The Site” isn’t about the next few years.
It’s about the bonanza it can expect in coming decades, given its 60-year role as the leader in nuclear research and the growing interest in nuclear energy as an alternative to generating electricity without producing greenhouse gases.
The lab is uniquely poised for the role.
Half of the Department of Energy’s $800 million nuclear energy research now goes through the INL (which spends half of its own budget on nuclear research).
The French firm Areva plans to build a $2 billion uranium enrichment plant near Idaho Falls by 2012.
And the Idaho lab is high on the radar screen for Congress.
The government just added $33 million to INL’s nuclear facilities budget for 2010. And the lab received half of all of Idaho’s federal stimulus money - the $468 million for nuclear cleanup made Idaho the fifth-highest state in per capita stimulus spending.
As climate change has challenged many long-held environmental tenets, it has placed a renewed call on something most environmentalists have stood against for years: nuclear power, which is relatively carbon-free.
The debate is at the heart of climate-change legislation that has passed the House and is now in the Senate. If Congress pushes nuclear power in the bill, it could more than double the number of reactors built by 2030.