Name three different types of machine guarding

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

Water at 70°f and streams enter the mixing chamber at the same mass flow rate, determine the temperature and the quality of the exiting stream. 0 psia is heated in a chamber by mixing it with saturated water vapor at 20 psia. if both streams enters the mixing chamber at the same mass flow rate, determine the temperature and the quality of the existing system.

What is the heat treatment of metals? what is the benefit of it? why and how it's useful? answer in details, do not write by hand.