describe two example of each thin and thick cylinder found in engineering devices or structures.?

Question

in that question we need to explain their purpose also.

Answer 1

Pipes for transporting fluids at high pressure - thick cylinders
Pressure vessel for holding fluids at pressure - often have a thick cylindric section
Ducting for air at low pressure - often thin cylinders relative to their diameter
Tanks for storing liquids - again thin cylinders relative to diameter

Answer 2

Thick and thin relative to what? A carbon nano-tube that could be used as an X-ray or micro wave generator would have to be about the thinnest tube to be used in an engineering problem (for the moment anyway). I would thing that the steel skeleton of buildings would also count. If its a purely a tube, the fuselage of an aircraft, a submarine, or the space-station, might suffice.