Applying fatigue failure criteria in 3D, determine the final relation (equation) for the following cases: - Considering only the internal pressure fluctuating from Pmax to Pmin Numerical Application: Pmax=1.0P and Pmin=0.2P σu= 690 MPa σe= 345 MPa Kf=1 ; Define P ? - Considering completely reversed internal pressure (P) and completely reversed bending moment (M) Write just the final equation (no numerical application)

Two flowing streams of argon gas are adiabatically mixed to form a single flow/stream. one stream is 1.5 kg/s at 400 kpa and 200 c while the second stream is 2kg/s at 500 kpa and 100 ? . it is stated that the exit state of the mixed single flow of argon gas is 150 c and 300 kpa. assuming there is no work output or input during the mixing process, does this process violate either the first or the second law or both? explain and state all your assumptions.

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.