You've experienced convection cooling if you've ever extended your hand out the window of a moving vehicle or into a flowing water stream. with the surface of your hand at a temperature of 30 degree c. determine the convection heat flux for a vehicle speed of 35 km/h in air at -5 degree c with a convection coefficient of 40 w/m2 . k and a velocity of 0.2 m/s in a water stream at 10 degree c with a convection coefficient of 900 w/m2 k. which condition would feel colder? contrast these results with a heat loss of approximately 30 w/m2 under normal room conditions.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia