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Physics World Digest: May 2002 edition

April 25, 2002

Lasers clear "leaves on the line"
They cause delays, cancellations and untold frustration to rail passengers in the UK every autumn. It`s no wonder then that "leaves on the line" have become something of a national joke, regarded by the public as merely the latest excuse for poor railway services. Now, however, a new Hampshire-based company set up by a former Royal Navy officer has developed a laser that could make leaves on the line a thing of the past. The laser, which is attached to a moving train, sends a series of intense pulses of light onto the track, producing minute explosions that blow the crushed leaf residue off the rails. LaserThor has already carried out trials with Railtrack and plans to have its first products on the market next year. (p. 21)
Contact: Malcolm Higgins, LaserThor (tel. +44 (0)7788 582244; e-mail malcolmhiggins@laserthor.com)

Surround-sound sensation
Anyone who has tried setting up a "surround-sound" system in their living room will know just how difficult it can be. You need a large-screen television, at least five loudspeakers strategically arranged around the room, plus a wealth of unsightly cables. Now a former radio astronomer has developed a single loudspeaker panel that promises surround sound without the clutter. Dubbed the "digital sound projector", the device - developed by Tony Hooley of 1Limited - is based on the same "phased-array" technology used in radio telescopes and underwater sonar applications. It contains an array of 254 tiny transducers that vibrate to produce sound waves that are then reflected off the walls and ceilings of the room to create true surround sound. (p. 25)
Contact: Tony Hooley, President, 1Limited, St John`s Innovation Centre, Cambridge, UK (tel. +44 (0)1223 422290; mobile +44 (0)7836 591421; fax +44 (0)1223 422291; e-mail tony@1limited.com)

Bend it like Beckham
With the most famous foot in England currently encased in plaster, injured England captain David Beckham has time on his hands to contemplate the first detailed study into the aerodynamics of a football. Retired physicist John Wesson reveals how he and two friends fixed a long bar to a Land Rover and then hung a football from a string attached to the bar. By driving down the runway of a local airfield and measuring the ball`s deflection with a video camera, Wesson was able to calculate the drag force on the ball at different speeds. He believes that the drag on a football is determined by the indentations on the surface of the ball where the leather panels are stitched together. (p. 41)
Contact: John Wesson, 26 Galley Field, Abingdon, UK (tel. +44 (0)1235 523056; e-mail jo@wessonj.fsnet.co.uk)

Pioneer of the paranormal
"Physicists have an emotional response when they hear anything connected with parapsychology," says Nobel-prize winning theorist Brian Josephson in this month`s Physics World. "Their opinion of parapsychology research is not based on evaluation of the evidence, but on a dogmatic belief that all research in this field is false." Josephson, who shared the Nobel Prize for Physics in 1973 for his pioneering work on superconductivity, now spends his time thinking about how the brain works, investigating language and consciousness, and pondering the fundamental links between music and the mind. In a rare interview, he defends his research into parapsychology and accuses his critics of being misguided and narrow-minded. (p. 10)
Contact: Brian Josephson, Mind-matter Unification Project, Cavendish Laboratory, Cambridge (tel. +44 (0)1223 337260; fax +44 (0)1223 337356; e-mail bdj10@cam.ac.uk; Web www.tcm.phy.cam.ac.uk/~bdj10)

Ear we go - again
When David Kemp of University College London placed a sensitive microphone next to a human eardrum in 1979, he was surprised to find that our ears emit a faint hum. Some people`s ears even emit sounds that are loud enough to be heard by passers by. His discovery showed that the ear works like an "active receiver" - both receiving and emitting sound. Thomas Duke describes how physicists are finally beginning to understand how the ear works as an active receiver and what powers it at the cellular level. The cochlea is best thought of as a choir, containing many "voices" each of which is ready to sing along with any incoming sound that falls within its own range of pitch. (p. 29)
Contact: Thomas Duke, Cavendish Laboratory, Cambridge, UK (tel. +44 (0)1223 337256; fax +44 (0)1223 337356; e-mail td18@cam.ac.uk)

Also in this issue:
EU outlines research challenge (p. 5); Physics enters debate on ancient poetry (p. 11); What is the most beautiful experiment in physics? (p. 17); The magnetic attraction of Jupiter (p. 23); The road to new materials (p. 25); E-tongue tastes success (p. 26); The origin of neutrino mass (p. 35); The poetry of James Clerk Maxwell (p. 64)

Institute of Physics