A bare wire suspended in air generates Joule heating at the rate q' = 1 W/m (Watts per m length of wire). The wire is a bare cylinder of radius r i= 0.5 mm, which is suspended in air at 25 degree C, and its thermal conductivity is 80 W/m K. If the heat transfer coefficient between the air and wire is h = 15 W/m2 K, determine the surface and center temperatures of the wire. It is proposed to cover this wire with a plastic sleeve of electrical insulation, the outer radius of which will be r 0 = 1.5 mm. The thermal conductivity of the plastic material is k = 0.30 W/m middot K. Will the plastic sleeve improve the wire-ambient thermal contact, or will it provide a thermal insulation effect? By adding the insulation, the convective heat transfer coefficient decreases to h = 11 W/m2 K. Determine the new surface and center temperatures of the wire. Are these temperatures reduced?