Acoustics researchers at the Georgia Institute of Technology (www.me.gatech.edu) have developed a piezoceramic actuator to eliminate brake squeals that occur when a vehicle slows down and the brake pads contact the rotor, setting up a vibration that manifests itself as a high-pitched noise. Mounted inside the brake piston, the actuator can suppress the vibration by applying bursts of a 20-kHz dithering frequency—above the human hearing range—to the backing plate of the inside brake pad. An open-loop control system that is connected to the brake-light switch, the actuator does not need any detector or logic system to determine the proper control frequency.
Sales of semiconductors, interconnects, and other electronic components in North America were flat through the second quarter of 2015, reflecting a pattern that’s been repeating itself for several years.
An in-depth survey of 700 current and future users of 3D printing holds few surprises, but results emphasize some major trends already in progress. Two standouts are the big growth in end-use parts and metal additive manufacturing (AM) most respondents expect.
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