A

Angle of Repose

At this angle pile of granular material remain stable, so this is angle between the sloping surface of a pile and the horizontal plane.

E

Elasticity 

The ability of a body to return to its original shape and size after forces are removed. The applied forces or influence tend to deform the body permanently.

N

NBR Nitrile Butadiene Rubber is a famous synthetic elastomer with excellent resistant to Oil, Chemicals.
T

Transition Distance
Distance between center of pulley to fully trough idler roller.

W

Wear Resistance

Ability of body or obeject to resist against surface damage during its usage.