A new method has been proposed to design and fabricate a metallic microelectromechanical capacitive accelerometer, in this paper. The conventional MEMS fabrication methods, as well as the micro wire electrical discharge machining (µWEDM) method, have been employed to fabricate the proposed accelerometer. The µWEDM offers several advantages including its capability for attaining a proof mass of higher thickness, as well as using dense metals, in the accelerometers, thus providing better control over noise reduction and damping. This sensor has the proof mass of 6.8 mg which leads to the low Brownian noise of 1.2 µg/ √ Hz. The proof mass-beam structure of the accelerometer has been made of steel, which has higher yield strength and fracture toughness than silicon, enabling the accelerometer to withstand high-amplitude accelerations. Conducted tests showed that this sensor operates in the range of 100 g. Thanks to its low noise (due to the larger proof mass) and capability to measure high-amplitude accelerations (due to the high yield strength of steel), the dynamic range of the proposed accelerometer is improved considerably in comparison with the conventional MEMS accelerometers. The presented accelerometer is also operable in the air which facilitates its packaging

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Study of the behavior of fluids inside micro and nanochannels has become particularly important with the extensive advances in micro- and nanofluidic systems. Capillary filling is a phenomenon that occurs in microchannels when the fluid is in contact with the channel walls. This phenomenon can be controlled by introducing certain characteristics in the channel walls and these channels are used in specific applications such as micro-reactors and pressure-sensitive switches. In this paper new insights about some effective parameters in the capillary are provided by which it is possible to increase or decrease the fluid’s velocity or even stop its motion at a specific point in the microchannel. The influence of different regimes governed the capillary action on the fluid’s velocity is studied. Furthermore, the effect of introducing certain obstacles on the microchannel wall on the capillary action and its relation with the contact angle of fluid is investigated. 2D FEM capillary simulation for three different fluids at contact angles of 30, 50 and 60° showed that at 30° and 50° fluid passes the obstacle and at 60° remains pinned at the obstacle. Finally, certain grooves on the channel walls are used to increase fluid’s velocity. Results showed that the grooves increase fluid velocity by 15%.