Exposure to high concentration of gaseous ammonia can cause lung damage. to prevent gaseous ammonia from leaking out, ammonia is transported in its liquid state through a pipe (k = 25 w/m∙k, di = 0.038 m, to = 0.04 m, and l = 10 m). since liquid ammonia has a normal boiling point of −33.3°c, the pipe needs to be properly insulated to prevent the surrounding heat from causing the ammonia to boil. the pipe is situated in a laboratory, where the average ambient air temperature is 20°c. the convection heat transfer coefficients of the liquid ammonia and the ambient air are 100 w/m2∙k and 20 w/m2∙k, respectively. determine the insulation thickness for the pipe using a material with k = 0.75 w/m∙k to keep the liquid ammonia flowing at an average temperature of −35°c, while maintaining the insulated pipe outer surface temperature at 10°c.