Sci/tech

Spiders spin unique phononic material
July 25, 2016 01:50 PM - Rice University via EurekAlert!

New discoveries about spider silk could inspire novel materials to manipulate sound and heat in the same way semiconducting circuits manipulate electrons, according to scientists at Rice University, in Europe and in Singapore.

A paper in Nature Materials today looks at the microscopic structure of spider silk and reveals unique characteristics in the way it transmits phonons, quasiparticles of sound.

The research shows for the first time that spider silk has a phonon band gap. That means it can block phonon waves in certain frequencies in the same way an electronic band gap - the basic property of semiconducting materials - allows some electrons to pass and stops others.

The researchers wrote that their observation is the first discovery of a "hypersonic phononic band gap in a biological material."

Spiders spin unique phononic material
July 25, 2016 01:50 PM - Rice University via EurekAlert!

New discoveries about spider silk could inspire novel materials to manipulate sound and heat in the same way semiconducting circuits manipulate electrons, according to scientists at Rice University, in Europe and in Singapore.

A paper in Nature Materials today looks at the microscopic structure of spider silk and reveals unique characteristics in the way it transmits phonons, quasiparticles of sound.

The research shows for the first time that spider silk has a phonon band gap. That means it can block phonon waves in certain frequencies in the same way an electronic band gap - the basic property of semiconducting materials - allows some electrons to pass and stops others.

The researchers wrote that their observation is the first discovery of a "hypersonic phononic band gap in a biological material."

Unlocking the secret to cheaper solar power
July 25, 2016 01:23 PM - American Institute of Physics (AIP) via ScienceDaily

As climate change garners more attention around the world, scientists at the University of Virginia and Cornell University have made critical advances in understanding the physical properties of an emerging class of solar cells that have the potential to dramatically lower the cost of solar energy.

Solar cells remain a focal point of scientific investigation because the sun offers the most abundant source of energy on earth. The concern, however, with conventional solar cells made from silicon is their cost. Even with recent improvements, they still require a significant amount of electricity and industrial processing to be manufactured.

In 2009, energy researchers turned their attention to a class of materials called "metal halide perovskites," or MHPs. They are sprayed on like paint onto solid objects, says Joshua Choi, an assistant professor of chemical engineering at the University of Virginia. As the solution dries, the MHPs crystallize into a thin film that can be used to capture energy in a solar cell.

New lithium-oxygen battery greatly improves energy efficiency, longevity
July 25, 2016 12:31 PM - Massachusetts Institute of Technology via EurekAlert!

Lithium-air batteries are considered highly promising technologies for electric cars and portable electronic devices because of their potential for delivering a high energy output in proportion to their weight. But such batteries have some pretty serious drawbacks: They waste much of the injected energy as heat and degrade relatively quickly. They also require expensive extra components to pump oxygen gas in and out, in an open-cell configuration that is very different from conventional sealed batteries.

But a new variation of the battery chemistry, which could be used in a conventional, fully sealed battery, promises similar theoretical performance as lithium-air batteries, while overcoming all of these drawbacks.

The new battery concept, called a nanolithia cathode battery, is described in the journalNature Energy in a paper by Ju Li, the Battelle Energy Alliance Professor of Nuclear Science and Engineering at MIT; postdoc Zhi Zhu; and five others at MIT, Argonne National Laboratory, and Peking University in China.

Soon solar will be the cheapest power everywhere
July 22, 2016 10:04 AM - Chris Goodall, The Ecologist

Solar is already the cheapest available power across large swathes of the tropics, writes Chris Goodall - its cost down 99.7% since the early 70s. Soon it will be the cheapest electricity everywhere, providing clean, secure, affordable energy for all.

Towards the end of last year, Shell CEO Ben van Beurden made a little-noticed remark. He said that solar would become the "dominant backbone" of the world's energy system.

He didn't give a date for his prediction, or indeed define what 'dominant' means, but he accepted that the sun will eventually provide the cheapest energy source across almost all of the world.

Mars rover's laser can now target rocks all by itself
July 21, 2016 05:07 PM - DOE/LOS Alamos National Laboratory via EurekAlert!

New software is enabling ChemCam, the laser spectrometer on NASA's Curiosity Mars rover, to select rock targets autonomously -- the first time autonomous target selection is available for an instrument of this kind on any robotic planetary mission. Developed jointly at Los Alamos National Laboratory and the Research Institute in Astrophysics and Planetology in Toulouse, France, the ChemCam (chemistry and camera) instrument aboard Curiosity "zaps" rocks on Mars and analyzes their chemical make-up. While most ChemCam targets are still selected by scientists, the rover itself now chooses multiple targets per week.

"This new capability will give us a chance to analyze even more rock and soil samples on Mars," said Roger Wiens, principal investigator for ChemCam at Los Alamos. "The science team is not always available to pick samples for analysis. Having a smarter rover that can pick its own samples is completely in line with self-driving cars and other smart technologies being implemented on Earth."

Offshore wind powers ahead as prices drop 30% below nuclear
July 19, 2016 09:30 AM - Kieran Cooke, The Ecologist

The cost of offshore wind power in the North Sea is 30% lower than that of new nuclear, writes Kieran Cooke - helped along by low oil and steel prices, reduced maintenance and mass production. By 2030 the sector is expected to supply 7% of Europe's electricity. Output from the Dogger Bank project will be 1.2 GW (gigawatts) - enough to power more than a million homes. Next year, a 150-turbine wind farm off the coast of the Netherlands is due to start operating, and other schemes along the Dutch coast are in the works. Denmark, Sweden and Portugal are major investors in offshore wind, and China has ambitious plans for the sector. Wind farms - both onshore and offshore - are a key ingredient in renewable energy policy, and an important element in the battle against climate change. WindEurope, an offshore wind industry group, says that at the present rate of installations it's likely Europe will be producing about 7% of its electricity from offshore wind by 2030.

Offshore wind developers benefit from falling costs

By some calculations, all this building work would seem to make little economic sense. Fossil fuel prices are low on the world market, and constructing offshore wind farms several kilometres out at sea, in often treacherous conditions, has traditionally been an expensive business.

Hummingbird vision wired to avoid high-speed collisions
July 18, 2016 04:10 PM - University of British Columbia via EurekAlert!

Hummingbirds are among nature's most agile fliers. They can travel faster than 50 kilometres per hour and stop on a dime to navigate through dense vegetation.

Now researchers have discovered that the tiny birds process visual information differently from other animals, perhaps to handle the demands of their extreme aerial acrobatics.

"Birds fly faster than insects and it's more dangerous if they collide with things," said Roslyn Dakin, a postdoctoral fellow in the UBC's department of zoology who led the study. "We wanted to know how they avoid collisions and we found that hummingbirds use their environment differently than insects to steer a precise course."

Note: Watch a video of the experiments here: https://youtu.be/6Z45BaswaOs

Scientists at UBC placed hummingbirds in a specially-designed tunnel and projected patterns on the walls to figure out how the birds steer a course to avoid collisions when they are in flight. They set up eight cameras to track the movement of hummingbirds as they flew through a 5.5-metre long tunnel.

Trees rely on a range of strategies to hunt for nutrient hot spots
July 18, 2016 03:59 PM - Penn State via EurekAlert!

On the surface, trees may look stationary, but underground their roots -- aided by their fungal allies -- are constantly on the hunt and using a surprising number of strategies to find food, according to an international team of researchers.

The precision of the nutrient-seeking strategies that help trees grow in temperate forests may be related to the thickness of the trees' roots and the type of fungi they use, according to David Eissenstat, professor of woody plant physiology, Penn State. The tree must use a variety of strategies because nutrients often collect in pockets -- or hot spots -- in the soil, he added.

"What we found is that different species get nutrients in different ways and that depends both on that species' type of root -- whether it's thin or thick -- and that species' type of mycorrhizal fungi, which is a symbiotic fungus," said Eissenstat. "What we show is that you really can't understand this process without thinking about the roots and the mycorrhizal fungi together."

Tree species with thicker roots -- for example, the tulip poplar and pine - avoid actively seeking nutrient hot spots and instead send out more permanent, longer-lasting roots. On the other hand, some trees with thinner roots search for nutrients by selectively growing roots that are more temporary, or by using their fungal allies to find hot spots.

A battery inspired by vitamins
July 18, 2016 03:12 PM - John A. Paulson School of Engineering and Applied Sciences via EurekAlert!

Harvard researchers have identified a whole new class of high-performing organic molecules, inspired by vitamin B2, that can safely store electricity from intermittent energy sources like solar and wind power in large batteries.

The development builds on previous work in which the team developed a high-capacity flow battery that stored energy in organic molecules called quinones and a food additive called ferrocyanide. That advance was a game-changer, delivering the first high-performance, non-flammable, non-toxic, non-corrosive, and low-cost chemicals that could enable large-scale, inexpensive electricity storage.

While the versatile quinones show great promise for flow batteries, Harvard researchers continued to explore other organic molecules in pursuit of even better performance. But finding that same versatility in other organic systems has been challenging.

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