Answer:
c) can be made with a variety of surface finishes.
Explanation:
The missing options are;
When it comes to concrete work in construction, the concrete can be cast either in-situ or in form of pre-cast concrete.
Now in-situ concrete means concrete done on the construction site being built while pre cast concrete simply means concrete cast outside in a factory or yard and brought to site to mount.
These pre cast concrete could have different surface finishes as required as this is one of it's advantages over in situ because there is a lot of space and room to have the desired concrete finish.
a) are typically manufactured on site and then hoisted into place.
b) cannot be fiber-reinforced.
c) can be made with a variety of surface finishes.
d) never include insulation.
e) often are unreinforced.
Answer:
2062 lbm/h
Explanation:
The air will lose heat and the oil will gain heat.
These heats will be equal in magnitude.
qo = -qa
They will be of different signs because one is entering iits system and the other is exiting.
The heat exchanged by oil is:
qo = Gp * Cpo * (tof - toi)
The heat exchanged by air is:
qa = Ga * Cpa * (taf - tai)
The specific heat capacity of air at constant pressure is:
Cpa = 0.24 BTU/(lbm*F)
Therefore:
Gp * Cpo * (tof - toi) = Ga * Cpa * (taf - tai)
Ga = (Gp * Cpo * (tof - toi)) / (Cpa * (taf - tai))
Ga = (2200 * 0.45 * (150 - 100)) / (0.24 * (300 - 200)) = 2062 lbm/h
