A diffuse radiation surface has

An object has the shape of cubical box of side $$10cm,$$ with no top cover. The box is placed inside a room whose dimensions are much larger than those of the box. All the five surfaces of box are at a temp of $${500^ \circ }C$$ and have an emissivity of $$0.6.$$ The walls of the room are at $${25^ \circ }C$$ and have an emissivity of $$0.4.$$ All these surfaces can be assumed to be diffuse-gray. Find the net radiative heat loss from the inner surface of the box to the walls of the room.
Stephen Boltzmann constant $$5.67 \times {10^{ - 8}}\,\,W/{m^2}{K^4}$$. View factor between two parallel square plates placed directly opposite to each other is $$0.2$$

In shell and tube heat exchanger, baffles are mainly used to

A one shell pass, one tube-pass heat exchanger, has counter flow configuration between the shell side and tube side fluids. The total number of tubes within the heat exchanger is $$10$$ and the tube dimensions are $$ID=10$$ $$mm,$$ $$OD=12$$ $$mm$$ and length $$=1m.$$ saturated dry steam enters the shell side at a flow rate of $$2$$ $$kg/s$$ and the temp of $${100^ \circ }C.$$ In the tube side, cold water enters at a flow rate of $$10$$ $$kg/s$$ with an inlet temp of $${25^ \circ }C.$$ The $$OHTC$$ based on the outer surface area of the tubes is $$50$$ $$W/{m^2}K.$$ The specific heat of water is $$4.18$$ $$kJ/kg$$-$$K$$ and the latent heat of steam is $$2500$$ $$kJ/kg.$$ What is the condition of the steam at the exit.