If a steel cylindrical specimen is stressed nominally to 65 MPa, what stress level exists at the tip of an elliptical surface flaw, whose length is 6.3 microns and radius of curvature is 1,066 nanometers ? Answer Format: X (no decimal) Unit: MPa Aside: You should be asking yourself if this magnified stress is a big deal or not ... Note that the yield strength of a typical low-carbon ductile steel is around 250 MPa.

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.