A multilevel programming for shale gaswater supply chains accounting for tradeoffs between economic and environmental concerns Abstract   This study develops a multilevel programming model for the planning shale gaswater supply chains. A set of leaderfollowerinteractive objectives with emphases of water consumption, economic performance, and pollutant discharge are integrated into a sequential decisionmaking process. Satisfactory degree is introduced to tackle the computationally challenging problem based on an interactive fuzzy approach. Operational decisions regarding water resources allocation, transportation mode selection, and pollutant discharge control would be achieved. Results reveal that the environmentally or economicallyaggressive strategies would be generated when a single goal for optimizing economic benefits or pollutant discharge. The multiobjective decisions are limited by the selected weights. However, the multilevel model would provide more comprehensive schemes due to its sequential consideration of the economicenvironmental concerns. Findings from the multilevel model can facilitate (a) balancing the conflicts among different decision makers, (b) timing and siting for shale gas production, and (c) managing water resources for pollutant discharge control.

Optimal Production and Maintenance Scheduling for a Multiproduct Batch Plant Considering Degradation Abstract   Performance decay due to asset degradation is an important constraint in industrial production and therefore needs to be actively considered. This paper focuses on shortterm scheduling for multiproduct batch processes with sequencedependent degradation and is motivated by a case study in which the sequence of multiplegrade batch runs impacts evolution of fouling. A continuoustime scheduling formulation is proposed to incorporate realistic features of the case study processes. The precedence scheduling concept for the sequential process is employed to model sequences of multiproduct orders and maintenance and is implemented using the general disjunctive programming method. The scheduling formulation is applied to the case study and further analyzed through comprehensive computational tests, which illustrates the efficacy of the proposed formulation.