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Sensors Provide Early Diagnosis Of Microcracks In Aircraft |
 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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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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ElectronicDesignNet News
A How To Tutorial On Logic Analyzer Basics For Digital Design |
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Test & Measurement / Data Acquisition - Tuesday
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Monday, 07 May 2007 |
This tutorial provides an overview of logic analyzer basics; most logic analyzers are really two analyzers in one: a timing analyzer and a state analyzer. Let's assume that you need to simultaneously look at the inputs and outputs of a 16-bit counter to determine a timing error, but you have only a 2-channel scope – how do you look all of the required signals? Or let's suppose that you've just developed timing diagrams for a board full of digital circuitry. How do you verify them? What do you use to capture and analyze the signals on the board? Without the appropriate tool, solving these kinds of problems can be very time consuming. For the above problems, a logic analyzer is the best solution. This article provides a quick overview of logic analyzer basics and offers ideas as to what can be achieved using a logic analyzer....more  (0) Comments |
Understanding Ethernet-Based Industrial Communication Protocols |
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Product Design - Wednesday
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Monday, 07 May 2007 |
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By exchanging information across the Web with open application protocols such as HTTP, SMTP, and FTP, people across the world can share and collaborate. These protocols rely on the physical layer of Ethernet. Engineers and managers in industrial automation are also using protocols based on Ethernet, of which one example is Modbus TCP/IP. New protocols including Ethernet/IP and PROFINET highlight a clear trend where industrial protocols are in transition to the Ethernet physical layer....more (0) Comments |
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Last Updated ( Monday, 07 May 2007 )
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Consumers Demand Greener Products, And Tech Companies Are Responding |
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Business News - Monday
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Monday, 07 May 2007 |
More US consumers are familiar with the concept of green products and how their actions affect the environment than they were last year, according to a new survey.
As electronic and computer companies increasingly move toward greener products and recycling procedures, a 2007 ImagePowera Green Brands Survey shows a shift in U.S. consumer attitudes. "Green is no longer an issue marginalized to fanatical environmentalists," pollsters with WWP's Landor Associates, Penn, Schoen & Berland Associates and Cohn & Wolfe, said in a prepared statement. "Nearly all Americans display green attitudes and behaviors versus a year ago."...more (0) Comments |
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