 be cost competitive with fans and easier to manufacture. Further energy savings could be realized by using piezoelectric actuators. One of the practical implications of this technology could be to forestall the need to use costlier heat sinks made from copper. "The industry could con- tinue to use aluminum and retain its advantages of design simplicity, lower cost, and lower weight," says Goldman. 8.6.2 VIDA In applications like high-powered military electronics, automotive compo- nents, radars, and lasers, power dissipation needs exceed 100 watts per square centimeter and may surpass 1,000 watts per square centimeter. For such higher demands, vibration-induced droplet atomization (VIDA) could be used. This sophisticated system uses atomized liquid coolants-such as water-to carry heat away from components. Also developed at Georgia Tech by Glezer's group, VIDA uses high-frequency vibration produced by piezoelectric actua- tors to create sprays of tiny cooling liquid droplets inside a closed cell attached to an electronic component in need of cooling. COOLING TECHNOLOGIES The droplets form a thin film on the heated surface, allowing thermal energy to be removed by evaporation. The heated vapor then condenses, either on the exterior walls of the cooling cell or on tubes carrying liquid coolant through the cell. The liquid is then pumped back to the vibrating diaphragm for reuse. "A system like this could work in the avionics bay of an aircraft," says Samuel Heffington, a Georgia Tech research engineer. "We have SO far been able to cool about 420 watts per square centimeter and ultimately expect to increase that to 1,000 watts per square centimeter." SynJets and VIDA have both been licensed to Atlanta-based Innovative Fluidics, which will use them to develop products that will be designed to meet a broad range of electronic device cooling needs. 8.6.3 Wiggling Fans Another promising approach to device cooling is based on tiny, quiet fans that wiggle back and forth to help cool future laptop computers, mobile phones