New Steel-Cable Corrosion Test Method Could Replace Manual Checks:

Details: Researchers at the University of Buffalo measure the corrosion level of a steel-cable strand using a non-invasive monitoring technique, aimed to replace structurally invasive manual checking processes for concrete-embedded steel cables on bridges. “Checking post-tension structures for corrosion is a challenging problem,” says Alireza Farhidzadeh, a University of Buffalo PhD candidate in structural engineering. He says projecting the accurate evolution of corrosion to a cable is nearly impossible because of a variables such as the salting of roads during the winter and the rain and snow levels during the year. Structurally invasive corrosion monitoring techniques are required, such as drilling into the concrete to check structural cables manually, he says.

To create a non-invasive technique, Farhidzadeh and his team outfitted a seven-wire cable strand with eight piezoelectric transducers and sent guided ultrasonic waves (GUWs) to monitor any changes in frequency as the corrosion level evolves.

“Measuring velocity and the time of flight of the frequencies sent out, you can localize where the corrosion or micro cracks occur in the cable,” says Farhidzadeh The permanently attached transducers allow the team to perform real-time passive structural monitoring and routine inspections, without seeing the cable.

The research consists of three phases, two of which are complete. The first was to evaluate the seven-wire strand cable under load to create a baseline for the following tests. The second phase was submerging the cable in a saltwater tank with 2-volts DC current running through, creating accelerated electrochemical corrosion.

New tech may replace windscreen wipers in cars

Detail -- The humble windshield wiper may soon become a thing of the past - thanks to a new system that creates vibrations to shake off water or any debris from the car windscreen. The McLaren Group, Britain's most advanced automobile company and a leading designer of Formula 1 supercars, is planning to dispose of the windscreen wiper with new technology adapted from fighter jets.

The new system will use high-frequency sound waves similar to those used by dentists for removing plaque from teeth and by doctors for scanning unborn babies. By in effect creating a force field, water, insects, mud and other debris will be repelled from the screen. As well as improving visibility, McLaren said that removing wipers could improve cars' fuel economy by eliminating the weight of wiper motors and streamlining the windscreen, 'The Times' reported. It would also prevent the problem in cold weather of wiper blades freezing to the glass. The system is expected to be introduced in McLaren's range of cars, which cost between about 170,000 pounds and 870,000 pounds, but is unlikely to be ready before 2015. While McLaren is reluctant to release details about its wiper-free windscreen, experts suggest that it may make use of ultrasound, waves outside the human hearing range, to create tiny vibrations on the windscreen. These would in effect shake off any object that landed on the screen. It could cost as little as 10 pounds to mass-manufacture.

"The obvious way of doing it is to have an ultrasonic transducer in the corner of the windscreen that would excite waves at around 30kHz to bounce across the windscreen," said Paul Wilcox, professor of ultrasonics at Bristol University's faculty of engineering. "You would not be able to see anything moving because the amplitude of vibration would be at the nanometre level," Wilcox said. It is not the first time that such a design has been suggested. In 1986, Japan's Motoda Electronics Company patented an ultrasonic windscreen wiper system, which used ultrasonic waves to push rain off a windscreen. Motoda's patent is not thought to have gone into production