Category Archives: IEEE Spectrum

Machine Vision Sees Into Chickens’ Futures

A jump to the left and a step to the right are signs of healthy activity, as chicken farmers who stroll among their flocks already know. Now a team led by robotics engineer Stephen Roberts at the University of Oxford has found that patterns in the collective motion of a flock of chickens can help farmers predict disease weeks before onset. Call it a chicken time warp.

Roberts and animal-welfare researchers at Oxford first tested their pattern-detection system by asking it to warn farmers before a flock got “peckish.” That’s not a euphemism for “hungry.” Well-fed hens, it turns out, sometimes take out their worm-hunting instincts on one another. The system, which consisted of cameras recording a flock, followed by computer analysis of the footage, beat human experts at flagging the at-risk flocks before the madness took its toll [“Computer System Counters Hen Horrors,” September 2010].

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Lithium-Air Batteries Get a Recharge

Lithium, the lightest metal, when paired with oxygen from the atmosphere, makes for a tantalizing partnership in a lightweight battery. In theory, this “lithium-air battery” offers several times the energy per kilogram of today’s lithium-ion batteries. But so far, in laboratory tests the lithium gets distracted by dead-end chemical reactions that prevent the batteries from recharging. A one-shot battery is fine for a wristwatch, but not for a next-generation electric vehicle.

Last month, researchers in Rome and Seoul, South Korea, reported designing a lithium-air battery that did not have the recharging problem, achieving approximately 100 charge and discharge cycles with little capacity loss. And this week, a research team led by chemist Peter Bruce of the University of St. Andrews, in Scotland, reports in the journal Science a differently designed lithium-air battery that reached 100 cycles, losing only 5 percent of its capacity in the process. Bruce says that these recent results show that lithium-air batteries can sustain “a truly reversible reaction.” The group measured the mix of chemicals involved, showing that the lithium was really being recycled through a reversible substance, lithium peroxide (Li2O2), during each charge and discharge. Continue reading Lithium-Air Batteries Get a Recharge

Snails in a Race for Biological Energy Harvesting

Bioengineers are getting better at replacing and enhancing body parts, but so far they’ve struggled to power implantable bionics without resorting to clunky batteries. But because blood carries energy in the form of electron-rich molecules like glucose and delivers it to all parts of the body, it is a tempting target for researchers. Chemist Evgeny Katz of Clarkson University, in Potsdam, N.Y., and his colleagues recently tested a new kind of electrode, which, when implanted in Neohelix albolabris snails and immersed in the snails’ blue, bloodlike hemolymph, produced a small, steady supply of electricity over a period of months. The researchers reported the work in March in the Journal of the American Chemical Society. Continue reading Snails in a Race for Biological Energy Harvesting

Optical Fiber Watches Wounds

Monitoring a wound as it heals should get easier thanks to a new kind of optical fiber that could become a part of everyday bandages. The fiber’s coating alters in color in response to changes in acidity, a key health indicator in wounds. The core of the fiber carries light to and from an attached device, which caregivers could use to monitor a wound in real time, says Bastien Schyrr, a Ph.D. student in biomedical engineering at the University of Fribourg, in Switzerland, who last month presented results of a laboratory trial in which the enhanced bandage detected acidity changes in a solution containing human serum. Continue reading Optical Fiber Watches Wounds