Tey+Yi+Shen+s+doubt

Tey Yi Shen s doubt

1. What is "relaxation time"? is there any easy example? I can't understand from the internet explanation.

Deborah number, De is defined as the ratio between a characteristic time of the material (tR) and a characteristic time of the deformation process (tE), which is taken as the experimental time-scale. Thus, De = tR/tE The characteristic time (tE) of the material is stress relaxation time, i.e. time taken for stress within the material to become dissipated. By definition, the De is zero for Newtonian liquids and infinite for Hookean bodies. It follows that high De corresponds to solid-like behaviour and low De to liquid-like behaviour. A material therefore appear solid-like either because it has a very long characteristic time (tR) or because the deformation process (tE) we are using to study it is very fast*. In the intermediate region falling between the two classical extremes (Newtonian viscous behaviour and Hookean elastic response), materials may display a combination of both properties,and their behaviour is called viscoelastic.

I Think you can understand after repeating reading this many many times﻿. Copy and paste from portal.[Shen]

2. How does the production of low fat magerine be considered as shear thinning behavior?

3. Difference between ringing and creaming. Ringing for oil/ beverage?

4."Even a large-diameter, slow moving centrifugal pump introduces a relatively high amount of shear." Is it because in this large diameter pipe, more force need to be applied to flow the fluid. Thus the resulting quite high shear in the process. (not desirable especially for very-sensitive-shear fluid.