## What kind of equation is the diffusion equation?

From Wikipedia, the free encyclopedia The diffusion equation is a parabolic partial differential equation. In physics, it describes the macroscopic behavior of many micro-particles in Brownian motion, resulting from the random movements and collisions of the particles (see Fick’s laws of diffusion).

When to use product rule in diffusion equation?

The product rule is used to rewrite the anisotropic tensor diffusion equation, in standard discretization schemes, because direct discretization of the diffusion equation with only first order spatial central differences leads to checkerboard artifacts. The rewritten diffusion equation used in image filtering:

### Which is the best description of the process of diffusion?

Diffusion • This “jiggling about” by lots of molecules leads to diffusion • Individual molecules follow a random walk, due to collisions with surrounding molecules • Diffusion = many random walks by many molecules – Substance goes from region of high concentration to region of lower concentration

When was the self-diffusion of water discovered?

In 1827, so-called Brownian motion was found, where the self-diffusion of water is visualized by the motion of pollen micro particles. Nevertheless, Brownian motion had not been recognized as a diffusion problem until the Einstein theory of Brownian motion in 1905.

## How does the change in temperature affect the diffusion equation?

The stronger the change of the temperature gradient, the more the incoming heat flow differs from the outgoing heat flow. This results in a larger net heat flow and thus a temporally stronger increase in temperature.

When to add a negative sign to the diffusion equation?

Therefore a negative sign must be added to the upper equation: If in equation ( 4) the net heat flow Q* n is replaced by the difference of the outgoing and incoming heat flow dQ*, then the following relationship applies to the temporal change of the temperature: