Table 6.

Variables

$x_f$	If factory f is open, equals 1; otherwise 0.
$x_i$	If CDC i is open, equals 1; otherwise 0.
$x_b$	If RLC b is open, equals 1; otherwise 0.
$Y_{\mathit{sf}}^{\mathit{ts}}$	Quantity of units of raw material sent from supplier s to factory f with shipping alternative ts,
$Y_{\mathit{fi}}^{\mathit{tf}}$	Quantity of units of product sent from factory f to CDC i with shipping alternative tf,
$Y_{\mathit{ic}}^{\mathit{ti}}$	Quantity of units of product sent from CDC i to customer c with shipping alternative ti,
$Y_{\mathit{ci}}^{\mathit{tc}}$	Quantity of units of returned product collected from customer c to CDC i with shipping alternative tc,
$Y_{\mathit{if}}^{\mathit{ti}}$	Quantity of units of returned product available for remanufacturing and refurbishing sent from CDC i to factory f with shipping alternative ti,
$Y_{\mathit{ib}}^{\mathit{ti}}$	Quantity of units of returned product unsuitable for remanufacturing and refurbishing sent from CDC i to RLC b with shipping option ti,
$Y_{\mathit{bs}}^{\mathit{tb}}$	Quantity of units of recycled product sent from RLC b to supplier s with shipping option tb,