A 3D Invisibility Cloak Masks Sound Waves

Durham, NC -- Contrary to earlier predictions, Duke University engineers have found that a three-dimensional sound cloak is possible, at least in theory.

Such an acoustic veil would do for sound what the "invisibility cloak" previously demonstrated by the research team does for microwaves--allowing sound waves to travel seamlessly around it and emerge on the other side without distortion.

"We've devised a recipe for an acoustic material that would essentially open up a hole in space and make something inside that hole disappear from sound waves," said Steven Cummer, Jeffrey N. Vinik Associate Professor of Electrical and Computer Engineering at Duke's Pratt School of Engineering. Such a cloak might hide submarines in the ocean from detection by sonar, he said, or improve the acoustics of a concert hall by effectively flattening a structural beam.

As in the case of the microwave cloak, the properties required for a sound cloak are not found among materials in nature and would require the development of artificial, composite metamaterials.

The engineering of acoustic metamaterials lags behind those that interact with electromagnetic waves (i.e. microwaves or light), but "the same ideas should apply," Cummer said.

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Source: Kendall Morgan - Duke University

http://news.duke.edu/2008/01/3dsoundcloak1.html

Self-Healing Rubber Invented by French Researchers

A material that is able to self-repair even when it is sliced in two has been invented by French researchers.

The as-yet-unnamed material - a form of artificial rubber - is made from vegetable oil and a component of urine.

The substance, described in the journal Nature, produces surfaces when cut that retain a strong chemical attraction to each other.

Pieces of the material join together again as if never parted without the need for glue or a special treatment.

This remarkable property comes from careful engineering of the molecules in the material.

The French researchers are already making kilogramme quantities in their Paris laboratories and say the process is almost completely green, and could be completely so with a few adjustments.

The secret of the substance lies in how the molecules are held together.

A piece of normal rubber, says Dr Ludwik Leibler, who headed the research, is actually a single molecule with billion upon billions of smaller units chemically welded together to form a giant tangled network.

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Source: Roland Pease
BBC Radio Science Unit

The YouTube Killer - Hulu Video Site Launched

Associated Press - Los Angeles - Oct. 29, 2007

NBC and Fox are set to launch an advertising-supported online video site that hosts programming from varied entertainment companies in a bid to seize viewers from Google Inc.'s YouTube, the broadcasters said.

A test version of the site, Hulu.com, goes online Monday, with plans to premiere a final version in a few months, company officials said.

The site, developed by News Corp. and NBC Universal, a unit of General Electric Co., offers free viewing of full-length films and TV episodes, supported by advertising.

It will host programming from the two networks, as well as TV shows and films from Sony Corp. and Metro-Goldwyn-Mayer Inc.

"Consumers identify with shows and films," rather than networks, Hulu chief executive Jason Kilar said. "When you aggregate great content together, it makes things easier for the user."

Hulu's debut comes amid tensions between entertainment companies and popular online video sites, such as YouTube, where unauthorized clips from shows often appear.

Viacom Inc., which owns Comedy Central, MTV, VH1 and many other cable channels, is suing YouTube for $1 billion, claiming massive copyright infringement of clips from popular shows, including "The Daily Show with Jon Stewart."

YouTube has said it follows copyright laws by removing protected video upon request.

Hulu will legally offer hundreds of episodes of current shows such as NBC's "30 Rock" and Fox's "The Simpsons," as well as older shows such as "Lou Grant" and "Lost in Space."

Its movie offerings will consist of films that have already been edited for television broadcast, which will contain short ads online in the places where they would appear on TV.

The shows will be available at Hulu.com, as well as on distribution partner Web sites such as AOL, MSN, MySpace, Yahoo and Comcast.

It will also provide viewers with tools that let them embed full episodes on their own blogs, Web sites or personal profile pages.

Users would also be able to select short clips from shows, such as Jay Leno's monologue on "The Tonight Show," and e-mail a link to the content to friends.

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Source: FOXNews.com