Brownian motion aging phenomena

Some liquid colloid systems show a double refraction when they are set in laminar flow. The classical example is the V2O5 sol which (at least after ageing) consists of needle-shaped particles with a crystalline character the sol itself with its particles randomly oriented by Brownian motion is isotropic if now one makes it flow through a tube or between two coaxial cylinders, one of which is rotating, it becomes double refracting The same is the case with many macromolecular sols This phenomenon, streaming double refraction of sols, is also reckoned as accidental double refraction, because it only occurs through a constraint exerted on the system ... 

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