Two 1-in-diameter bars of stainless steel [k = 17 W/m C] are brought into end-to-end contact

Two 1-in-diameter bars of stainless steel [k = 17 W/m ∙ ºC] are brought into end-to-end contact so that only 0.1 percent of the cross-sectional area is in contact at the joint. The bars are 7.5 cm long and subjected to an axial temperature difference of 300ºC. The roughness depth in each bar (Lg/2) is estimated to be 1.3 μm. The surrounding fluid is air, whose thermal conductivity may be taken as 0.035W/m ∙ ºC for this problem. Estimate the value of the contact resistance and the axial heat flow. What would the heat flow be for a continuous 15-cm stainless-steel bar?