Technician A says that a full face shield is necessary to MIG weld. Technician B says that welding goggles are sufficient. Who correct ?

The temperature of air decreases as it is compressed by an adiabatic compressor. a)- true b)- false

An air conditioning system consist of a 5 cm diameter pipe, operating at a pressure of 200 kpa. the air initially enters the pipe at 15°c with a velocity of 20 m/s and relative humidity of 80%. if the heat supply throughout the process is 960 w, determine the relative humidity and the temperature at the outlet

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.