Vibration control of cylindrical, electro-rheological fluid (ERF) dampers were studied. Single- as well as multi-electrode cylindrical ERF dampers were designed, built and tested under a forced vibration motion. Closed-loop, on-line control systems utilizing bang-hang and linear proportional controller were implemented to control the damping capacity of the ERF dampers. In addition, the designs were modified to reduce the required activation voltage. These modifications include increasing the electrode surface area as well as the number of electrodes. The damping ability of the dampers was further enhanced by using two identical dampers in series connection.

Experiments are reported on the thermal performance of model fan-sink assemblies consisting of a small axial flow fan which impinges air on a square array of pinfns. Cylindrical, square, and diamond shape cross section pin-fins are considered. The pin-fin heat transfer coefficient is found to be maximum immediately under the fan blades and minimum below the fan hub and near the corners of the array. The overall heat sink thermal resistance, R, decreases with an increase in either applied pressure rise or fan power and fin height. At fixed applied pressure rise, R is minimized when the fin pitch-to-diameter ratio is maximum. At fixed.fan power, R is minimized when the pitch-to-diameter ratio is reduced toward unity. Finally, cylindrical pinfins give the best overall fan-sink performance.

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