the two-input, one-output control volume
(Forall (?Self ?Time) (<=> (Active ?Time 2-1-Control-Volume ?Self) (And (2-1-Control-Volume ?Self) (Active ?Time 2-Input-Control-Volume ?Self) (Active ?Time 1-Output-Control-Volume ?Self))))
(Forall (?Self ?Time) (<=> (Active ?Time 2-1-Control-Volume ?Self) (And (2-1-Control-Volume ?Self) (Active ?Time 2-Input-Control-Volume ?Self) (Active ?Time 1-Output-Control-Volume ?Self)))) (Inherited-Facet-Value Slot-Value-Type 2-1-Open-Feedwater-Heater-System Opn-Fwt-Htr-Cv 2-1-Control-Volume) (=> (2-1-Open-Feedwater-Heater-System ?Self) (And (Value-Cardinality ?Self Opn-Fwt-Htr 1) (Value-Type ?Self Opn-Fwt-Htr 2-1-Open-Feedwater-Heater) (Value-Cardinality ?Self Opn-Fwt-Htr 1) (Value-Cardinality ?Self Opn-Fwt-Htr-Cv 1) (Value-Type ?Self Opn-Fwt-Htr-Cv 2-1-Control-Volume) (Value-Cardinality ?Self Opn-Fwt-Htr-Cv 1) (Value-Cardinality ?Self Adbtc-Mxng-Prcs 1) (Value-Type ?Self Adbtc-Mxng-Prcs Steady-Flow-Adiabatic-Mixing) (Value-Cardinality ?Self Adbtc-Mxng-Prcs 1) (Cv-Component (Opn-Fwt-Htr-Cv ?Self) (Opn-Fwt-Htr ?Self)) (Component-Cv (Opn-Fwt-Htr ?Self) (Opn-Fwt-Htr-Cv ?Self)) (Process-Cv (Adbtc-Mxng-Prcs ?Self) (Opn-Fwt-Htr-Cv ?Self)))) (=> (Opn-Fwt-Htr-Cv $X $Y) (2-1-Control-Volume $Y))