MEMS micro-electro-mechanical

Microfabrication techniques used for the production of MEMS (micro electro-mechanical systems) have been successfully used to produce highly efficient micro fluidic systems. 

Without being itself a screening device, the reactor of Jensen et al. [6, 42, 43] also has to be mentioned because they opened up a completely new field in catalysis by combining MEMS (micro-electro-mechanical systems) technology with a chip-based catalytic reactor (Fig. 4.10). A mixing-tee was equipped with heaters and temperature and flow sensors, thus giving on-stream information about the reaction conditions. 

Technologies MEMS Micro Electro Mechanical Systems... 

Almost all types of sensors can be attached to such a sensor node as long as the power consumption is in relation to the purpose of the sensing system. Low-power sensors are first choice and that is the reason why micro-sensors called MEMS (micro electro-mechanical systems) are very attractive to be combined with such a system. MEMS are small integrated devices combining electrical and mechanical components that could be produced for about 50 each. Because the process elements and internal linkage movements are now small, these MEMS-based transducers consume very little power. The low cost, low power and small size of MEMS-based transducers have revolutionized the way we can measure. This includes also the combination of sensor data and the formation of networks of sensors as well as combination with low power video techniques (VSLI cameras). 

The Knudsen number (mean free path/characteristic length) observed in gas flow in micro-channels suggests that rarefied gas effects come into play - some MEMS (micro-electro-mechanical systems) devices, for example, operate in a regime normally associated with low pressure, high altitude (aerospace) devices. 

The operation of the rotary pump depends on the viscous forces and can operate in any situation where viscous forces are dominant. Therefore, they are suitable for flow of low viscosity liquids in micro ducts as well as the flow of highly viscous liquids such as heavy polymers in macro ducts. Together with its simplicity from design point of view and this viscous nature makes rotary pumps suitable for scientific and industrial applications of MEMS (Micro-Electro-Mechanical-Systems), NEMS... 

Seismic Acceierometers, Fig. 9 Principal elements of a MEMS (micro-electro-mechanical system) accelerometer with capacitive transducer. The mass is the upper mobile capacitor plate which can rotate around the torsion bars. The displacement, proportional to acceleration, is sensed... 

Chan et al. (2005), have realised micro fuel cells through an approach that combines thin film materials with MEMS (micro-electro-mechanical system) technology. The membrane electrode assembly was embedded in a polymeric substrate (PMMA) which was micromachined through laser ablation to form gas flow channels. The micro gas channels were sputtered with gold to serve as current collectors. This cell utilized the water generated by the reaction for the humidification of dry reactants (H2 and O2). The peak power density achieved was 315 mW cm (901 mA cm" at 0.35 V) for the H2-O2 system with 20 ml min" O2 supply and H2 at 10 psi in dead ended mode of operation. A Y shaped microfluidic channel is depicted in Fig. 21. 

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