SciTech

Science Briefs: Promise for magnesium-ion batteries, new LED technology can widen WiFi bandwidth, sky color affects body clock

Researcher Jordi Cabana: “We hope that this work will open a credible design path for a new class of high-voltage, high-energy batteries.”
Researcher Jordi Cabana: “We hope that this work will open a credible design path for a new class of high-voltage, high-energy batteries.” University of Illinois at Chicago

Magnesium-ion batteries may be boon to electric cars

A team at the University of Illinois at Chicago has taken a significant step toward the development of a battery that could outperform the lithium-ion technology used in electric cars such as the Chevy Volt.

The researchers showed they can replace the lithium ions, each of which carries a single positive charge, with magnesium ions, which have a plus-two charge, in battery-like chemical reactions, using an electrode with a structure like those in many of today’s devices.

“Because magnesium is an ion that carries two positive charges, every time we introduce a magnesium ion in the structure of the battery material we can move twice as many electrons,” said Jordi Cabana, UIC assistant professor of chemistry and principal investigator on the study. “We hope that this work will open a credible design path for a new class of high-voltage, high-energy batteries.” uic.edu

New LED technology can up WiFi bandwidth

Researchers at Oregon State University have invented a new technology that can increase the bandwidth of WiFi systems by 10 times, using LED lights to transmit information.

The technology could be integrated with existing WiFi systems to reduce bandwidth problems in crowded locations, such as airport terminals or coffee shops, and in homes where several people have multiple WiFi devices.

Recent advances in LED technology have made it possible to modulate LED light more rapidly, opening the possibility of using light for wireless transmission in a “free space” optical communication system.

The prototype, called WiFOcq, uses LEDs that are beyond the visual spectrum for humans and creates an invisible cone of light about one meter square in which the data can be received. To address the issue of a small area of usability, the researchers created a hybrid system that can switch between several LED transmitters installed on a ceiling, and the existing WiFi system.

The system can potentially send data at up to 100 megabits per second. Although some current WiFi systems have similar bandwidth, it has to be divided by the number of devices, so each user might be receiving just five to 10 megabits per second, whereas the hybrid system could deliver 50 to 100 megabits to each user. oregonstate.edu

Sky color affects how body clock operates

Scientists at England’s University of Manchester have found that the color of light has a major impact on how our body clock measures the time of day.

In research published in the journal PLOS Biology, they looked at the change in light around dawn and dusk to analyze whether color could be used to determine time of day. Besides the well-known changes in light intensity that occur as the sun rises and sets they found that during twilight, light is reliably bluer than during the day.

Mice were placed beneath the sky for several days and their body temperature was recorded. As expected for nocturnal creatures, the highest body temperatures occurred just after night fell when the sky turned a darker blue – indicating that their body clock was working optimally.

When only the brightness of the sky was changed, with no change in the color, the mice became more active before dusk, demonstrating that their body clock wasn't properly aligned to the day/night cycle. manchester.ac.uk

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