(Press-News.org) CAMBRIDGE, Mass. -- In recent years, many airplane manufacturers have started building their planes from advanced composite materials, which consist of high-strength fibers, such as carbon or glass, embedded in a plastic or metal matrix. Such materials are stronger and more lightweight than aluminum, but they are also more difficult to inspect for damage, because their surfaces usually don't reveal underlying problems.
"With aluminum, if you hit it, there's a dent there. With a composite, oftentimes if you hit it, there's no surface damage, even though there may be internal damage," says Brian L. Wardle, associate professor of aeronautics and astronautics.
Wardle and his colleagues have devised a new way to detect that internal damage, using a simple handheld device and heat-sensitive camera. Their approach also requires engineering the composite materials to include carbon nanotubes, which generate the heat necessary for the test.
Their approach, described in the March 22 online edition of the journal Nanotechnology, could allow airlines to inspect their planes much more quickly, Wardle says. This project is part of a multiyear, aerospace-industry-funded effort to improve the mechanical properties of existing advanced aerospace-grade composites. The U.S. Air Force and Navy are also interested in the technology, and Wardle is working with them to develop it for use in their aircraft and vesselsAdvanced composite materials are commonly found not only in aircraft, but also cars, bridges and wind-turbine blades, Wardle says.
One method that inspectors now use to reveal damage in advanced composite materials is infrared thermography, which detects infrared radiation emitted when the surface is heated. In an advanced composite material, any cracks or delamination (separation of the layers that form the composite material) will redirect the flow of heat. That abnormal flow pattern can be seen with a heat-sensitive (thermographic) camera.
This is effective but cumbersome because it requires large heaters to be placed next to the surface, Wardle says. With his new approach, carbon nanotubes are incorporated into the composite material. When a small electric current is applied to the surface, the nanotubes heat up, which eliminates the need for any external heat source. The inspector can see the damage with a thermographic camera or goggles.
The new carbon nanotube hybrid materials that Wardle is developing have so far shown better mechanical properties, such as strength and toughness, than existing advanced composites.
### END
MIT engineers devise new way to inspect materials used in airplanes
2011-03-26
ELSE PRESS RELEASES FROM THIS DATE:
'Can you hear me now?' Researchers detail how neurons decide how to transmit information
2011-03-26
PITTSBURGH—There are billions of neurons in the brain and at any given time tens of thousands of these neurons might be trying to send signals to one another. Much like a person trying to be heard by his friend across a crowded room, neurons must figure out the best way to get their message heard above the din.
Researchers from the Center for the Neural Basis of Cognition, a joint program between Carnegie Mellon University and the University of Pittsburgh, have found two ways that neurons accomplish this, establishing a fundamental mechanism by which neurons communicate. ...
Slip and Falls: A Problem That Doesn't Slip Away
2011-03-26
Someone slips and falls in a store or a restaurant. They are injured. The injured sues and the business loses the case or settles. One would think the first thing the business would do would be to fix the problem that caused the injury to avoid another injury, and in turn, another personal injury lawsuit.
But one would be wrong. A story in the Minneapolis Star Tribune tells the story of a woman injured in a slippery parking lot of a Denny's. The downspouts on the restaurant run under a sidewalk and into the parking lot. During the winter, the drain ices over. It was ...
Basics of Benefits for Disabled Children
2011-03-26
Children who are born with disabilities, or who become disabled during their childhood years, may be eligible to receive payments through the government's Supplemental Security Income (SSI) benefits. The requirements for children to receive SSI are strict and are based on the nature of the disability and the family's total income. However, if eligible, the payments can be a helpful supplement to other household income and contribute to the care and well-being of disabled children, which can be medically intensive and costly.
Income Requirements
One goal of SSI payments ...
Surprise! Biodiversity and resource use may co-exist in tropical forests
2011-03-26
Contrary to popular belief, the biodiversity of a tropical forest may be conserved while its resources are used to support local household livelihoods, according to a new study published in the March 25 issue of Science. But biodiversity and resource use are most likely to successfully co-exist in forests that are managed under systems that receive inputs from local forest users or local communities.
These study results imply that one important way for governments to simultaneously promote biodiversity and forest-based livelihoods is to formalize the rights of local people ...
Texas Legislature Considers New Sexting Bill
2011-03-26
Child pornography laws are aimed at protecting children; by criminalizing the possession and distribution of child pornography, lawmakers aim to eliminate the harm to children when such materials are created. The penalties are steep--under Texas laws, possessing images of those under the age of 18 engaging in sexual conduct is a felony. Federal convictions result in long sentences. A child pornography conviction in any court will result in lifetime sex offender registration.
However, the phenomenon of teen 'sexting' has put legislators in a difficult position. The practice ...
Baylor, Texas A&M researchers find earliest people to inhabit the Americas
2011-03-26
Baylor University geology researchers, along with scientists from Texas A&M University and around the country, have found the oldest archaeological evidence of human occupation in the Americas at a Central Texas archaeological site located about 40 miles northwest of Austin.
"This find really rewrites history, so to speak, and changes our collective thought on the early colonization of North, Central and South America," said Dr. Lee Nordt, professor of geology at Baylor and dean of the College of Arts and Sciences, who is an author on the study. "What sets this study ...
Stranglers of the tropics -- and beyond
2011-03-26
Kudzu, the plant scourge of the U.S. Southeast. The long tendrils of this woody vine, or liana, are on the move north with a warming climate.
But kudzu may be no match for the lianas of the tropics, scientists have found. Data from sites in eight studies show that lianas are overgrowing trees in every instance.
If the trend continues, these "stranglers-of-the-tropics" may suffocate equatorial forest ecosystems.
Tropical forests contain more than half of Earth's terrestrial species, and contribute more than a third of global terrestrial carbon and a third of terrestrial ...
When Pit Bulls Attack, California Dog Owners Can Be Held Liable
2011-03-26
A recent news story in the Modesto Bee highlights the horror of dog bite attacks. A woman was attacked at a party by a pit bull that had never exhibited any signs of aggressiveness. As the story relates, "It lunged at [the woman's] face, biting down so hard that nearly half of her nose was ripped away."
The dog had been acting playfully moments before, so she had no warning of the attack and apparently had done nothing to provoke the pit bull. After two reconstructive surgeries, and the prospect of an unknown number of additional surgeries, the victim of the attack described ...
Debenhams Announces Mismatched Crockery Threatens Formal Dining
2011-03-26
Debenhams, the high street store, has announced that deliberately mismatched crockery, where no two plates or cups are the same, is the latest craze to hit the UK.
A fad which started in trendy restaurants has spread to homes all over Britain, latest sales show.
It's a rebellion against the rigid, formal, starched table cloth rules which have governed dinner parties in Britain for the last century.
Debenhams' spokesman Ed Watson said: "It's a Mad Hatter's approach to formal dining:
"Young people are turning their backs on one of the last surviving forms of ...
Large-scale assessment of the Arctic Ocean
2011-03-26
Large-scale assessment of the Arctic Ocean: significant increase in freshwater content since 1990s
The freshwater content of the upper Arctic Ocean has increased by about 20 percent since the 1990s. This corresponds to a rise of approx. 8,400 cubic kilometres and has the same magnitude as the volume of freshwater annually exported on average from this marine region in liquid or frozen form. This result is published by researchers of the Alfred Wegener Institute in the journal Deep-Sea Research. The freshwater content in the layer of the Arctic Ocean near the surface ...