Passive mixing

Fig. 1.71 How alloying with a noble metal produces a passive mixed potential and a marked reduction in corrosion rate (after Stern and Wissenberg )...

For experimental characterization, flow visualization by colored or fluorescent streams is the most facile method. Dilution-type experiments contact dyed and pure water streams (passive mixing) or standing volume portions (active mixing) in a type of photometric experiment. This is usually monitored with the aid of microscopic, photo, video or high-speed camera techniques (see e.g. [20]). 

Gap between electrodes (passive mixing) 800 pm Hydrophobic layer thickness 50 nm... 

Flow and mixing visualization were achieved by means of fluorescence dilution imaging [97]. A fluorescent droplet (1 mM fluorescein, 0.125 M KC1,0.125 M sodium hydroxide) was merged with a non-fluorescent droplet (0.125 M KC1, 0.125 M sodium hydroxide). The volume of the droplet in passive mixing was 1.75 pi, while 1.32 pi droplets were applied for active mixing. The actuation voltage was 30 V. The fluidic properties of the filler and droplet fluids were closely matched. The interfacial tension between the two liquids was 36 and 37 dyn cm4 for the non-fluorescent and the fluorescent droplets, respectively. 

Passive mixing of droplets with different fluidic properties... 

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