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In this paper, a novel array-type dynamic displacement output transmitter utilizing the tunable viscoelastic property of the electrorheological fluid as a control valve mechanism is studied. The characteristics of this ER valve are modeled theoretically and its major design parameters are identified thereafter. In addition, by applying electric field upon the concentric electrodes of the ER valve, the controllability of the output displacement due to the change in the stiffness and damping properties of the ER fluid is investigated experimentally. It is found that the cross-talk between two output units is insignificant in this design setup and therefore, two units can be operated independently. Finally, the transient responses of the output fluid chamber under the pulse-type controlled electric field with different duty time and phase are measured. It is concluded that under the sinusoidal excitation of the displacement amplitude, the output chamber can have minimal response as the controlled electric field is at its highest permissible magnitude and zero phase lag.

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Ni-P alloy has been shown to be a potential electrode material for hydrogen production from electrolysis. The enhancement of its electrocatalytic efficiency with micro patterned structures fabricated using microelectromechanical system (MEMS) process was investigated in this study. The cylindrical columns with diameter of 65�m and spacing of 105�m were fabricated in rectangular array and two different heights. From the potentiodynamic polarization curves measured in O.5M H 2 S04 solution, the current density at -O. 75V seE was increased from 181mA cm· 2 to 426 rnA cm· 2 , planar electrode to micro-structured electrode, which denoted a 2.35 times increase for hydrogen evolution reaction (HER) efficiency. It was noted that enhancement in HER efficiency was higher than the corresponding increment in apparent surface area. The electric field concentration at the edges of the columnar structure could contribute to the raise in efficiency. However, as the overplating occurred, the narrowing of the spacing between the top portions of the microcolumns could impede the electric flux into their bottom parts. Part of the surface area became less active in HER. Therefore, suitable configuration design in the micro-pattern is desired.