A natural gas pipeline is being built for service in low temperature conditions. At the expected temperature, 8 OD inch nominal pipe of ASTM A334 Grade 8 alloy steel material is to be used. The material has Sy ~ LN [75.4, 3.0] ksi. It will be subjected to an internal pressure load of P ~ LN [2.5, 0.6] ksi. Assume you can use the thin-wall pressure vessel equation to calculate the hoop stress. a. What is the value of z that corresponds to a reliability of 0.999995 against yielding

Steam in a heating system flows through tubes whose outer radius is 2.5 cm and whose walls are maintained at a temperature of 180 °c . circular aluminum alloy 2024-t6 fins ( k= 186 wm. k) of outer radius 3 cm and constant thickness 1 mm are attached to the tube. the space between the fins is 3 mm and thus there are 250 fins per meter of tube length. heat is transferred to the surrounding air at too-25 °c, with a heat transfer coefficient of 40 w/m2. k. manufacturer a claims that this system is rated at 3.5 kw per meter of tube length. if the fins are an integral part of the steam tube, find the heat transfer rate in kw for a 1-m length of tube. is manufacturer a's claim valid? compare the heat transfer rate from 1 meter of tube length if there are no fins.