Friday, 3 February 2017

Astronomers Discover Powerful Cosmic Double Whammy

credit NASA

Astronomers have discovered what happens when the eruption from a supermassive black hole is swept up by the collision and merger of two galaxy clusters. This composite image contains X-rays from Chandra (blue), radio emission from the GMRT (red), and optical data from Subaru (red, green, and blue) of the colliding galaxy clusters called Abell 3411 and Abell 3412. These and other telescopes were used to analyze how the combination of these two powerful phenomena can create an extraordinary cosmic particle accelerator.

Image credit: X-ray: NASA/CXC/SAO/R. van Weeren et al; Optical: NAOJ/Subaru; Radio: NCRA/TIFR/GMRT link

Wednesday, 1 February 2017

Money doesn’t grow on trees, but electricity might someday.

Iowa State University scientists have built a device that mimics the branches and leaves of a cottonwood tree and generates electricity when its artificial leaves sway in the wind.

Curtis Mosher (left), Eric Henderson (middle) and Mike Mcloskey (right) have assembled a prototype biomimetic tree that produces electricity. Such technology could appeal to a niche market in the future, according to the researchers. Photo by Christopher Gannon.

 Michael McCloskey, an associate professor of
genetics, development and cell biology who led the design of the device, said the concept won’t replace wind turbines, but the technology could spawn a niche market for small and visually unobtrusive machines that turn wind into electricity.

“The possible advantages here are aesthetics and its smaller scale, which may allow off-grid energy harvesting,” McCloskey said recently in his ISU laboratory. “We set out to answer the question of whether you can get useful amounts of electrical power out of something that looks like a plant. The answer is ‘possibly,’ but the idea will require further development.”

McCloskey said cell phone towers in some urban locations, such as Las Vegas, have been camouflaged as trees, complete with leaves that serve only to improve the tower’s aesthetic appeal. Tapping energy from those leaves would increase their functionality, he said.

In a paper published this month in the peer-reviewed academic journal PLOS ONE, the ISU research team delves into the world of biomimetics, or the use of artificial means to mimic natural processes. The concept has inspired new ways of approaching fields as varied as computer science, manufacturing and nanotechnology.

It’s unlikely that many people would mistake the prototype in McCloskey’s laboratory for a real tree. The device features a metallic trellis, from which hang a dozen plastic flaps in the shape of cottonwood leaves.

Curtis Mosher, an associate scientist at Iowa State and co-author of the paper, said it’s not that great of a leap from the prototype the researchers built to a much more convincing artificial tree with tens of thousands of leaves, each producing electricity derived from wind power.

“It’s definitely doable, but the trick is accomplishing it without compromising efficiency,” Mosher said. “More work is necessary, but there are paths available.”

Small strips of specialized plastic inside the leaf stalks release an electrical charge when bent by moving air. Such processes are known as piezoelectric effects. Cottonwood leaves were modeled because their flattened leaf stalks compel blades to oscillate in a regular pattern that optimizes energy generation by flexible piezoelectric strips.

Eric Henderson, a professor of genetics, development and cell biology who also works on the research team, envisions a future in which biomimetic trees help to power household appliances.

Such biomimetic technology could become a market for those who want the ability to generate limited amounts of wind energy without the need for tall and obstructive towers or turbines, Henderson said.

But McCloskey said making that vision reality means finding an alternative means of mechanical-to-electrical transduction, or a scheme for converting wind energy into usable electricity. The piezo method adopted for the ISU experiments didn’t achieve the efficiency the technology will need to compete in the market.

Piezoelectricity was an obvious place to start because the materials are widely available, Henderson said. But taking the next step will require a new approach.

Other transduction methods such as triboelectricity, or the generation of charge by friction between dissimilar materials, work at similar efficiency and can power autonomous sensors. However, McCloskey said it will require much greater efficiency – and further research – to produce a practical device.

Neutrino studies could improve understanding of the universe

A news report from Michigan State University

Trillions of neutrinos, or ghost particles, are passing through us every second. While scientists know this fact, they don’t know what role neutrinos play in the universe because they are devilishly hard to measure.

Credit: IceCube

New measurements of neutrino oscillations, observed at the IceCube Neutrino Observatory at the South Pole, have shed light on outstanding questions regarding fundamental properties of neutrinos. These new measurements of neutrinos as they change from one type to another while they travel were presented at the American Physical Society Meeting in Washington. They could help fill key gaps in the Standard Model, the theory that describes the behavior of fundamental particles at every energy scale scientists have been able to measure.

“While the Standard Model is an accurate theory, it leaves gaping holes, like the nature of dark matter and how a universe filled with matter, rather than anti-matter, arose from the Big Bang. We don’t know how to fill them yet,” said Tyce DeYoung, MSU associate professor of physics and astronomy. “We’re hoping that by measuring the properties of neutrinos, such as their masses and how they morph or oscillate from one into another, we may get some clues into these open questions.”
Neutrinos are weird particles. Unlike other elementary particles that make up ordinary matter, such as electrons and quarks, neutrinos have no electric charge. They’re also at least a million times lighter than any other particle known to science. In fact, their masses are so small scientists have not yet been able to measure them accurately.

With this in mind, DeYoung compares his work to a fishing trip, one in which scientists aren’t quite sure of the best bait to use. “Fishing” through the ice of Antarctica, though, is yielding promising results and narrowing the search.

“As physicists, we hoped the Higgs boson would point us to the physics that lies beyond the Standard Model; unfortunately, our measurements of the Higgs haven’t turned up many clues,” DeYoung said. “So we hope we may find something by studying neutrinos. IceCube detects neutrinos with a wider range of energies and distances than other experiments, so we cast a wide net.”

Energetic neutrinos produced by cosmic rays hitting the Earth’s atmosphere can be detected at the South Pole, using the Antarctic ice as a particle detector like no other on the planet.
The IceCube data suggest that one species of neutrino may comprise exactly equal amounts of two neutrino “flavors.”

“Neutrinos have a habit of changing, or oscillating, between three types, we call them ‘flavors,’” said Joshua Hignight, the MSU research associate who presented the new results at the meeting. “So, if one neutrino is a precisely equal mix of two flavors, it could be a surprising coincidence or there might be a deeper reason for it coming from the physics beyond the Standard Model.”

These measurements are consistent from results from other experiments using neutrinos with lower energies, but whether this flavor mixture is exactly balanced remains under debate. The IceCube physicists will continue to refine their analysis and collect more data. Future data will enable these measurements to be made more precisely, DeYoung said.

IceCube is the world’s largest neutrino detector, using a billion tons of the Antarctic ice cap beneath the U.S. Amundsen-Scott South Pole Station to observe neutrinos. It’s operated by a collaboration of 300 physicists from 48 universities and national laboratories in 12 countries. Construction was made possible by support from the National Science Foundation and other international funding agencies.

Contact(s): Layne Cameron Media Communications office: (517) 353-8819 cell: (765) 748-4827 , Tyce DeYoung Physics and Astronomy office: (517) 884-5511

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