This month in Scientific American

There is a bunch of stuff on the Scientific American website that should interest materials folks. The following links are free for now, but they may go behind a paywall later; so grab them now.

  1. Thw World’s Smallest Radio, made of one single carbon nanotube:

    [Carbon] nanotubes had some surprising properties. They came in a large variety of sizes and shapes: they were single-walled, double-walled and multiwalled. Some were straight, some were bent and some even looped back on themselves in toroidal configurations. Common to them all was their exceptional tensile strength, the resistance to being pulled apart along their length without breaking. The reason for this unusual property, Zettl says, is that “the force that holds the carbon atoms together in the carbon nanotube is the strongest bond in nature.” Nanotubes are also excellent conductors of electricity, far better than copper, silver or even superconductors. “It’s because the electrons don’t hit anything,” he explains. “The tube is such a perfect structure.”

    Zettl got the idea for a nanoradio when he decided he wanted to create tiny sensing devices that could communicate with one another and broadcast their observations wirelessly. “They were to do monitoring of environmental conditions,” he says. They would be distributed in the field near some factory or refinery and would radio their results back to some collecting point. Anyone could then go to Google “and click on the air quality of a city and see it in real time.” During the course of some experiments aimed at producing a nanotube mass sensor, one of Zettl’s graduate students, Kenneth Jensen, found that if one end of a carbon nanotube was planted on a surface, creating a cantilever, the beam would vibrate when a molecule landed on its free end. Molecules of different masses would make the beam vibrate at different frequencies. When Zettl noticed that some of these frequencies included those in the commercial radio band, the idea of using the cantilevered nanotube to make a radio became virtually irresistible.

  2. A nifty slide-show (and the pics explain the physics behind the technology) on how renewable energy and storage solutions stack up.

  3. Here’s a great story at the interface of cosmic events, geology, climate science and materials science! Did a comet hit the earth 12000 years ago?:

    Roughly 12,900 years ago, massive global cooling kicked in abruptly, along with the end of the line for some 35 different mammal species, including the mammoth, as well as the so-called Clovis culture of prehistoric North Americans. Various theories have been proposed for the die-off, ranging from abrupt climate change to overhunting once humans were let loose on the wilds of North America. But now nanodiamonds found in the sediments from this time period point to an alternative: a massive explosion or explosions by a fragmentary comet, similar to but even larger than the Tunguska event of 1908 in Siberia.

    Sediments from six sites across North America—Murray Springs, Ariz.; Bull Creek, Okla.; Gainey, Mich.; Topper, S.C.; Lake Hind, Manitoba; and Chobot, Alberta—yielded such teensy diamonds, which only occur in sediment exposed to extreme temperatures and pressures, such as those from an explosion or impact, according to new research published today in Science.

  4. Finally, there’s also an article on recent developments in making graphene sheets in large quantities.

    Silicon has transformed the digital world, but researchers are still eager to find substances that will make integrated circuits smaller, faster and cheaper. High on the list is graphene—planar sheets of honeycomb carbon rings just one atom thick. This nanomaterial sports a range of properties—including ultrastrength, transparency (because of its thinness) and blisteringly fast electron conductivity—that make it promising for flexible displays and superspeedy electronics. Isolated only four years ago, graphene already appears in prototype transistors, memories and other devices.

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About Abi

My name is T. A. Abinandanan, and I am a professor of Materials Engineering at the Indian Institute of Science, Bangalore.
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