Use 2 for diffusion coefficient

**Notes**

One of the most important parameters required in understanding of
the diffusion phenomenon in micro fluidics is the estimation of the
diffusion coefficient or diffusion constant of the solute particles
in a solvent. The diffusion coefficient determines how fast the
solute molecules move a certain distance in the solvent. In this
respect an approximate but very useful result can be obtained from
Einstein's relation for calculation of diffusion coefficient of
Brownian type motion of a spherical body. This is used in the
estimation of diffusion coefficient. There could be an error of
upto 30%.

The plot shows the diffusion coefficient of spherical bodies ranging from 0.1Å to 50,000Å in radius in water at room temperature (27°C).

-The solution is not highly concentrated.

-The fluid has constant viscosity.

-The viscosity of water is assumed to be 1 mPa-s.

Mechanics > Fluidics > Diffusion > Diffusion coefficient