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.
The amount of plastic clogging the ocean continues to grow. Some startling, not-so-good news has come out recently about the roles plastic is playing in the ocean, as well as more heartening news about efforts to collect and reuse it.
Some of our culture's most enduring robots appeared in the 80s. The Aliens series produced another evil android, and we saw light robot fare in the form of Short Circuit. Two of the great robots of all time also showed up: The Terminator and RoboCop.
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