Four-layer flow network for one chemical

Correspondingly, a quantity of the chemical is transferred from the tanks (first sub-layer) to the mobile stock (second sub-layer). In period 3 the loaded RTCs depart by train from site 1 carrying the chemical to site 2 where they arrive in period 4 (second and third sub-layer). In this period the RTCs are unloaded such that the local chemical stocks are replenished and, simultaneously, the RTCs are emptied. In this sequence two shipments are performed, i.e. (at least) two trains are chartered. 

To formalize the sketched network flow model, the remaining notation is introduced as follows A shipment flow of chemical s from site i to site j in period t is denoted by Xijts (second sub-layer). Shipment flows of loaded and empty RTCs are denoted by and respectively (third and forth sub-layer). Unloadiug flows and loading flows of 

The local chemical stock in tanks is denoted by sus (first sub-layer) whereas the mobile stock in RTCs is denoted by (second sub-layer). The number of loaded and empty RTCs at hand are described by srjj and sr . Table 3.13 summarizes aU notation introduced above (and some more). 

Sits stock level of chemical s 5 in period f s X at site i 6 X 

Using the aforementioned notation, the total operational costs for balancing the chemical production network by rail transports is expressed in (3.33) which constitutes the MC-RTF s objective function to be minimized. 

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Figure 3.9 Four-layer flow network for one chemical...

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