Hydrogen fuel balls
The name's Bond, Atomic Bond. And when it comes to carbon, atomic bonds linking carbon atoms are some of the strongest. That trait may allow tiny carbon spheres known as buckyballs to become mini fuel tanks for a future generation of fuel cells, say scientists at Rice University in Houston. They've calculated that these soccer ball-like structures – ranging from 60 to 2,000 atoms in size – can hold hydrogen under such intense pressure that the hydrogen nearly turns into a metal.
The research stems from efforts to find ways to cram more hydrogen into tighter spaces so that fuel cells can be small and strong enough to be practical for powering cars and trucks. Experiments had established that buckyballs could hold tiny amounts of hydrogen. The Rice team, led by Boris Yakobson, figured out a way to calculate how much hydrogen a buckyball of a given size could hold and at what point adding more hydrogen would burst the ball to release the gas.
The team acknowledges that ways still must be found to produce the tiny fuel tanks and fill them in a practical and cost-effective way. But if a way can be found, it likely would lead to buckyball-hydrogen crystals or a fine powder of hydrogen-packing buckyballs in your tank. The research appears in the current issue of the journal Nano Letters.
What's driving the decline and extinction of amphibians, particularly in the tropics? It turns out to be more complicated than some recent studies have suggested.
Two years ago, a study looked at the decline of Monteverde harlequin frogs in Costa Rica and amphibians elsewhere. It noted that the creatures had succumbed to a fungus, and attributed an increase in fungal outbreaks to global warming. (The Monitor reported on this in "The rainforest's vanishing species," in the June 21, 2007, issue.) Now, another team suggests that the fungus's spread is due more to typical modes by which infectious diseases are said to spread. The group says it finds no evidence that global warming plays a role in the spread of this particular fungus, according to the team, led by Karen Lips of Southern Illinois University.
The team looked at the problem in South and Central America, where the fungus in question itself is a relatively recent "invasive species." Using maps and statistical models, the team found that the fungus moved down the Central American isthmus and north along the Andes Mountains in "wave" patterns typical of spreading pathogens.
Because this lends predictability to where and when a pathogen might arrive, it should help wildlife managers develop strategies for blocking the fungus's spread. The study appears in the current issue of the PLoS Biology.
In computers, the need for speed seems insatiable. Now, researchers have shown that a sheet of graphite one single atom thick conducts electrons with far less resistance at room temperature than any material known. As a conductor of electricity, the material, dubbed graphene, beats out its nearest competitor, copper, by 35 percent.
The team, led by Michael Fuhrer, with the University of Maryland's Center for Nanophysics and Advanced Materials, also found that when used as a semiconductor – the basis for transistors and computer chips – graphene allows electrons far higher mobility, another key trait, than the previous record-holder, indium antimonide. Mobility determines how quickly a transistor made of the material can be switched on or off.
The team says graphene could lead to a new generation of smaller, faster computers. But first the right material on which to lay the graphene must be found. Electrical properties in these "substrates" can undercut graphene's advantages. The research appears in the latest issue of the journal Nature Nanotechnology.