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Spiders spin unique phononic material

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."

Global Economy Has Reduced Its Energy Intensity by One-Third Since 1990

Climate Change News - ENN - July 25, 2016 - 2:41pm
The global economy is becoming less energy intensive, using fewer fossil fuels to power productivity and economic growth, according to new data from the U.S. Department of Energy. Global energy intensity — a measure of energy consumption per unit of gross domestic product (GDP) — has decreased nearly one-third since 1990, the agency said. The U.S., for example, burned 5,900 British thermal units per dollar of GDP in 2015, compared to 6,600 BTUs in 2010.

Unlocking the secret to cheaper solar power

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.

Unlocking the secret to cheaper solar power

Climate Change News - ENN - July 25, 2016 - 2:23pm
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

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.

Bird ranges vary more than thought

Climate Change News - ENN - July 24, 2016 - 2:32pm
A new study of population trends among 46 ecologically diverse bird species in North America overturns a long-held assumption that the climate conditions occupied by a species do not change over time. Instead, birds that have increased in abundance over the last 30 years now occupy a wider range of climate conditions than they did 30 years ago, and declining species occupying a smaller range.A new study of population trends among 46 ecologically diverse bird species in North America conducted by avian ecologist Joel Ralston and colleagues at the University of Massachusetts Amherst overturns a long-held assumption that the climate conditions occupied by a species do not change over time.

Soon solar will be the cheapest power everywhere

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.

Soon solar will be the cheapest power everywhere

Climate Change News - ENN - July 22, 2016 - 11:04am
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.

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