BIEN 210 Lecture Notes - Lecture 12: Active Optics, Hydraulic Head, Electricity
12 Aug 2018
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Document Summary
Passive mixers = rely on diffusion & geometry of the device. Active mixers = enhance mixing by increasing the interfacial areas between the fluids. It can be achieved by piezoelectric, ultrasonic, or other mechanisms. T mixing & y mixing is possible, with spatial & temporal control of the mixing. Serpentine geometries allow more uniform & fast mixing: pumps: Fluid movement relative to a stationery charged or conducting surface through application of an electric field. The walls are negatively charged, creating a positive charge in immediate vicinity. Applying a potential is now enough to achieve movement of ions: electrophoresis. In the presence of an electric field the particle can be induced to move relative to a stationary (e. g. gel) or moving liquid: streaming potential. Occurs when an aqueous ion containing solution is forced to flow through a capillary or microchannel under an applied hydrostatic pressure in the absence of an applied electric field.
