In the thermal domain, all the ports are fluid ports.
Unlike 'terminal' in DME, a port is independent of a component.
It is a combination of a 'joint' and a 'terminal'.
the area of the cross section of the port
the elevation of the port with respect to some reference point
(Forall (?Self ?Time) (<=> (Active ?Time Port ?Self) (And (Port ?Self) (Active ?Time Thermal-Component ?Self)))) (=> (Port ?Self) (And (Quantity.Dimension (Port-Area ?Self) Area-Dimension) (Quantity.Dimension (Port-Elevation ?Self) Length-Dimension)))