Archive for July, 2011

Golf Is All About the X (and S) Factor

Published in ScienceNOW, 29 Jul 2011

Golfers can spend years honing their swings, but now it seems there are just a few key traits that separate amateurs from the pros. Researchers used eight digital cameras to record 3D videos of 10 professional and five amateur male golfers in action. Then, they measured several parameters, including the “S factor” (tilt of the shoulders) and the elusive “X factor” (rotation of hips relative to the shoulders), which is considered vital for power generation. Compared with the amateurs, the pros had S and X factors that were greater—often by as much as 10 degrees—and more consistent. [...]

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Cloak could hide ships from flowing water

Published in Physics World, 21 Jul 2011

Ships of the future may be able to move through the water without a creating a wake. That is according to a pair of physicists in the US, who have proposed a new type of material that lets water flow around an object as if it were not there at all. The design, which has yet to be built, could boost the energy efficiency of ships and submarines – and even prevent them from being detected. “The main function of [our] structure is to prevent fluid flowing around an object from ‘feeling’ that object,” says Yaroslav Urzhumov of Duke University.

The past five years have seen a flurry of research into invisibility cloaks. The first functioning cloak, which operated for electromagnetic waves in the microwave range, was demonstrated by a team led by David Smith at Duke University in 2006, and since then researchers have proposed and demonstrated cloaks that work for visible light, sound and even events in time. [...]

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Magnetic sponge can squeeze itself out

Published in Chemistry World, 19 Jul 2011

Researchers in Japan and Singapore have created a sponge that can wring itself out upon application of a magnetic field. The sponge, which is based on a network of nanomagnets, could be used as a capsule that delivers drugs to specific parts of the human body.

First developed in the late 1990s, magnetic sponges consist of nanoparticles linked up by spring-like molecules. When the sponges absorb water they expand, and their overall magnetic properties change. As a result, they have been touted for use as sensors that can sensitively detect the presence of water. [...]

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Making room for larger pores in zeolites

Published in Chemistry World, 15 Jul 2011

Chemists in Korea and the US have come up with a method to create catalysts known as zeolites with a hierarchical range of pore sizes, making way for the reaction of larger molecules than ever before. According to the researchers, the new zeolites could be used in the petrochemical industry to crack oil, or in organic synthesis.

Zeolites – crystalline materials with dense internal networks of pores – are one of the most widely used catalysts in the chemical industry today. They are used for applications as diverse as water purification, trapping nuclear waste and cracking heavy oil into shorter hydrocarbons. However, the catalytic applications of zeolites to date have been limited to smaller molecules: zeolite pore mouths tend to be smaller than 0.8 nanometres, so molecules larger than this cannot enter. [...]

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Physics student awaits espionage trial in Iran

Published in Physics World, 15 Jul 2011

A doctoral student who was detained when he tried to leave his native Iran earlier this year will go on trial tomorrow for charges related to espionage, according to sources close to him.

Omid Kokabee has been detained since late January or February this year when he was attempting to fly from Tehran airport to return to his studies at the University of Texas at Austin, US. Physics Worldunderstands that he is suspected of leaking Iranian scientific information and working with the CIA.

The trial, apparently based on charges of illegal earnings and communicating with a hostile government, is expected to be headed by Iranian justice Abolghasem Salavati. [...]

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Soft-drink cans beat the diffraction limit

Published in Nature, 8 Jul 2011

Sound, like light, can be tricky to manipulate on small scales. Try to focus it to a point much smaller than one wavelength and the waves bend uncontrollably — a phenomenon known as the diffraction limit. But now, a group of physicists in France has shown how to beat the acoustic diffraction limit — and all it needs is a bunch of soft-drink cans.

Scientists have attempted to overcome the acoustic diffraction limit before, but not using such everyday apparatus. The key to controlling and focusing sound is to look beyond normal waves to ‘evanescent’ waves, which exist very close to an object’s surface. Evanescent waves can reveal details smaller than a wavelength, but they are hard to capture because they peter out so quickly. To amplify them so that they become detectable, scientists have resorted to using advanced man-made ‘metamaterials’ that bend sound and light in exotic ways. [...]

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Liquid cement turns liquid metal

Published in Chemistry World, 1 Jul 2011

Concrete is heavy, tough and – you might think – a reliable insulator. But researchers in Japan have shown that, by doping it with free electrons, liquid cement can transform into a substance with metal-like electrical conductivity. According to the researchers, the surprising transition could lead to new types of semiconductor.

It has been known since the beginning of the nineteenth century that free electrons can be trapped in polar solvents such as water and ammonia. When an alkali metal is dissolved in ammonia, for example, the valence electrons are released into the solution, giving a deep blue colour when dilute and a bronze colour when more concentrated. These ‘solvated’ electrons are relatively stable, because each one is surrounded by an envelope of ammonia molecules. [...]

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