Consider refrigerant R -134a flowing in a smooth, horizontal, l0-mm-inner-diameter tube of wall thickness 2 mm. The refrigerant is at a saturation temperature of 15°C (for which Pv,sat = 23.75 kg/m³) and flows at a rate of 0.01 kg/s. Determine the maximum wall temperature associated with a heat flux of 10 s W/m² at the inner wall at a location 0.4 m downstream from the onset of boiling for tubes fabricated of

(a) Pure copper and

(b) AISI 316 stainless steel.