What is a U-Groove welding

Amass of 1.5 kg of air at 120 kpa and 24°c is contained in a gas-tight, frictionless piston-cylinder device. the air is now compressed to a final pressure of 720 kpa. during the process, heat is transferred from the air such that the temperature inside the cylinder remains constant. calculate the boundary work input during this process.

An open feedwater heater operates at steady state with liquid entering at inlet 1 with t? = 40°c and pl = 1 .2 mpa. water vapor att2-200°c and p2 = 1.2 mpa enters at inlet 2. saturated liquid water exits with a pressure of pa 1.2 mpa. neglect heat transfer with the surroundings and all kinetic and potential energy effects, determine the mass flow rate of steam at inlet 2 if the mass flow rate of liquid water at inlet 1 is given as 2 kg/s.

The sum of the normal stresses does not change as the stress state rotates through an angle. a)-trune b)- false