Sensors Provide Early Diagnosis Of Microcracks In Aircraft |
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Editorial notes
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Monday, 14 May 2007 |
 Today's aircraft are in service virtually around the clock and must operate reliably and safely at all times. An active sensor system helps to detect concealed fatigue cracks in aircraft bodies, thus reducing maintenance times considerably.
If a tiny crack in the hull of an aircraft remains undetected for a long time, it can easily spread and put passengers’ lives at risk. Each component is therefore subject to international maintenance regulations: Aircraft bodies must be thoroughly inspected every 15 to 18 months, depending on the type of plane. This often requires the technicians to dismantle an aircraft’s interior lining – an expensive and time-consuming process involving several days of downtime in the hangar. Researchers at the Fraunhofer Institute for Structural Durability and System Reliability LBF in Darmstadt are developing a sensor system that allows engineers to continuously monitor the condition of their aircraft and detect any damage at an early stage.
The system is based on piezoceramic sensors that are attached to the aircraft body in a network pattern. What is special about these sensors is that they start to oscillate when a voltage is applied to them – and when they are subjected to pressure, they generate voltage. The scientists make use of both effects: While the piezo foils cause part of the hull to oscillate, the others measure the component’s response to this stimulation. “We investigated the oscillation behavior of damaged struts and rivets in an aircraft body and compared it with that of intact parts,” explains LBF project manager Dirk Mayer. “If a component is defective, it oscillates at a different frequency from one that is intact when stimulated by the piezoceramics – just as a cracked glass sounds different from an undamaged one when you tap it with your fingernail.” In this way, the researchers can accurately track down faults and monitor their development – be it fatigue cracks in the hull and wings, or rivets and other joining parts coming loose. This form of observation is also referred to as ‘structural health monitoring’ (SHM).
“With the help of this system, any damage behind the lining or in difficult-to-reach places can be identified quickly and easily, thus reducing maintenance times and inspection costs,” says Mayer. The researchers have already performed tests on a hull component in the laboratory, and are now implementing the new technology with standardized piezo and electronic components. The system will then also be suitable for use in vehicle manufacture or engine and plant construction.
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Asian Countries Up In 2007 "E-Rankings" |
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Editorial notes
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Monday, 07 May 2007 |
Curiously Denmark remains the world’s most “e-ready” country in the latest rankings from the Economist Intelligence Unit. Tied for the number two spot were the US and Sweden. Hong Kong (4th), Singapore (6th), South Korea (16th), Taiwan (17th) and Japan (18th) experienced a lift in 2007 in both scores and ranks. At the other end of the rankings, Iran was last, the 69th country on the list.
Since 2000, the Economist Intelligence Unit has published its annual e-readiness ranking of the world's largest economies, using a model developed with the IBM Institute for Business Value. A country's "e-readiness" is a measure of its e-business environment, a collection of factors that indicate how amenable a market is to Internet-based opportunities. Increasingly, it is also about how individuals and businesses consume digital goods and services.
And, the global digital divide continues to narrow. While the worldwide average score increased, the gap between "haves" and "have-nots" decreased. But the latest rankings showed, if nothing else, that dominance can be ephemeral.
"Technology leadership in the world is becoming a fast-moving target," said Robin Bew, Editorial Director of the Economist Intelligence Unit. "Those at the top of today's league table cannot be complacent -- changing technologies, and attitudes to technology usage, mean that hard-won advantages can be quickly eroded by nimble-footed rivals."
"The role of governments in laying the structural and policy groundwork for an Internet-ready economy is essential today as business and society adapt to ongoing globalisation," said George Pohle, Global Leader, IBM Institute for Business Value.
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Letters to the Editor
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Tuesday, 01 May 2007 |
Dear Editor,
I hope you can help me or at least point me in the right direction. My neighbor just put up a huge CB Radio antennea, the thing is higher that the roof of his home, the problem is, now I have interference through our television set speakers. We can hear him speaking although it is not too clear. How can I fix the problem so that we can watch t.v. without hearing this noise? Any help you can give me would be greatly appreciated.
Sincerly,
Donna R.
Dear Donna,
If your neighbor's transmissions are interfering with your TV, the best thing for you to do is complain to the Federal Communications Commission. The FCC investigates cases of interference and they will determine if your neighbor's transmissions contain out-of-band signals. You might also try talking to your neighbor. If his antenna is for amateur radio rather than Citizens Band, "ham" radio operators have a policy of supplying a free filter for your TV in such cases.
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