Salema, M. I. G., APB Póvoa, and A. Q. Novais. "
Design and planning of supply chains with reverse flows." In
Computer Aided Chemical Engineering, edited by Luis Puigjaner and António Espuña, 1075-1080. Vol. 20. Elsevier, 2005.
AbstractA multi-product model for the design of global supply chains with reverse flows is proposed. Two levels of decisions are considered, one strategic and one tactical. The first is modelled through a macro perspective of time where the determination of the network structure and flows is accomplished. At tactical level, a micro perspective of time is considered, where production planning and inventory management are addressed in detail. A mixed integer linear programming formulation is developed which is solved with standard Branch and Bound techniques. The model accuracy and suitability are studied using a case study.
Mota, Bruna, Ana Carvalho, Maria Isabel Gomes, and Ana Paula Barbosa-povoa. "
Design and planning of sustainable supply chains." In
Sustainability of Products, Processes and Supply Chains: Theory and Applications, edited by Fengqi You, 333-353. Amsterdam: Elsevier, 2015.
Furtado, Pedro, Maria Isabel Gomes, and Ana Paula Barbosa-povoa. "
Design of an electric and electronic equipment recovery network in Portugal – Costs vs. Sustainability." In
Computer Aided Chemical Engineering, edited by E. N. Pistikopoulos, M. C. Georgiadis and A. C. Kokossis, 1200-1204. Vol. 29., 2011.
AbstractIn the last few decades there has been a massive growth in the Waste of Electric and ElectronicEquipment (WEEE). Part of these residues was already properly treated in some countries, but the lack of environmentally friendly options forced the European Union (EU) to take action. Two EU directives were created based on reduction, reutilization and recycling of WEEE. The need to properly designrecoverynetworks for such products appears as mandatory, where not only the economic aspects should be accounted for but also the environmental ones. The present paper addresses this problem and presents a generic optimization model for the design and planning of a recovery and treatment network of WEEE, minimizing both the costs and the environmental impacts that arise from the activity performed.
The model is applied to the real case of Amb3E, the Portuguese Association for the Management of Waste of Electric and ElectronicEquipment. Since its formation, in 2006, this organization has been registering an immense growth in the volume of residue collected, and faces now the necessity of reformulating its recoverynetwork. Both the actual cost structure and the best possible cost structure for Amb3E, given by the optimization of the model, are analyzed. These two scenarios are compared in order to turn clear the differences between them and to assess how the recoverynetwork of Amb3E can be improved through optimization. A similar analysis is performed from an environmental impacts perspective.
Gomes-Salema, M. I., A. Barbosa-Povoa, and A. Q. Novais. "
An Eco-Efficiency Study for a WEEE Recovery Network: The Portuguese Case." In
10th International Symposium on Process Systems Engineering, edited by RMB Alves, C. A. O. Nascimento and E. C. Biscaia Jr., 2073-2078. Vol. 27. Elsevier, 2009.
AbstractThe rapid growth of electric and electronic equipment waste (WEEE) transformed this waste stream into a worldwide problem. The Directive 2002/96/EC on electrical and electronic waste aims at the reduction of the environmental impact of WEEE, encouraging end-of-life management, eco design, life cycle analyses and extended producer responsibility. However, this legislation may not produce the results the legislator aimed for. In this work we analyse the environmental impact of a WEEE recovery network in the Portuguese context. With this aim, a model, previously developed by the authors for the optimal design of this network using economic indicators (Salema, 2007), was now adapted to design the network subjected to the minimization of environmental performance indices. The original mathematical formulation was found to be flexible and easily adapted to the two types of indices and the major differences between the optimal network configurations obtained, were identified and discussed.
Gomes, Isabel M., Luis J. Zeballos, Ana P. Barbosa-Povoa, and Augusto Q. Novais. "
Optimization of Closed-Loop Supply Chains under Uncertain Quality of Returns." In
21st European Symposium on Computer Aided Process Engineering, edited by E. Pistikopoulos, M. C. Georgiadis and A. Kokossis, 945-949. Vol. 29., 2011.
AbstractThe efficient design and operation of supply chains with return flows represent a major optimization challenge, given the high number of factors involved and their intricate interactions. In particular, the quality level of the return products has strong economic and societal implications and depends greatly on the type of product (glass, paper, electronic, oil, etc) and on the degree of consumers’ readiness, frequently promoted by various kinds of awareness raising campaigns. A multi-product multi-period model was previously developed by the authors [1] for the closed-loop supply chain (CLSC) design and planning, where strategic and tactical decisions were comprehensively considered. This model is now being extended to handle the uncertainty related to the quality of the returned products, which at this stage is modeled by a two-stage scenario-based stochastic approach. General strategies to solve optimization problems involving uncertainty tend to exhibit poor computational performance, due to the problem NP-hard complexity, which tends to worsen with the problem size. Therefore and, in addition, a model performance solution enhancement is also being explored. To increase the efficiency of the solution approach, an alternative representation to some of the integer variables employed in the mathematical formulation was developed, which is tested by means of computational experiments being performed on illustrative real sized examples.
Zeballos, L. J., M. I. Gomes, A. P. Barbosa-Povoa, and A. Q. Novais. "
Optimum Design and Planning of Resilient and Uncertain Closed-Loop Supply Chains." In
22nd European Symposium on Computer Aided Process Engineering, edited by Ian David Lockhart Bogle and Michael Fairweather, 407-411. Vol. 30. Computer Aided Chemical Engineering 30. London: Elsevier, 2012.
AbstractThe design and planning of efficient supply chains (SC) is a major challenge that increases when the return of products has to be accounted for, the so-called closed-loop supply chains (CLSC). In the present work the effect of disruptions and modifications in the operating conditions of CLSCs are investigated on the basis of a 2-stage scenario based model previously developed by the authors. Metrics derived from graph theory are used, along with more conventional economic and operational indices. A discussion on the results obtained is presented to assess how the design and planning of the CLSC respond to these challenges and how these metrics may contribute to this objective.
Mota, Bruna, Maria Isabel Gomes, and Ana Paula Barbosa-póvoa. "
Towards supply chain sustainability: balancing costs with environmental and social impacts." In
Computer Aided Process Engineering, edited by Andrzej Kraslawski and Ilkka Turunen, 895-900. Elsevier, 2013.
AbstractThis work presents a multi-objective optimization methodology that accounts for economic, environmental and social concerns in a supply chain with reverse flows. Environmental impact assessment is considered through the use of Recipe 2008. A social benefit indicator is developed where the creation of employment in less developed regions is preferred. The multi-objective approach is used to reach a solution of compromise between the three sustainability pillars. The model is applied to a case study developed in collaboration with a Portuguese company, leader in battery production.
Baptista, Susana, Maria Isabel Gomes, and Ana Paula Barbosa-povoa. "
A Two-Stage Stochastic Model for the Design and Planning of a Multi-Product Closed Loop Supply Chains." In
22nd European Symposium on Computer Aided Process Engineering, edited by Ian David Lockhart Bogle and Michael Fairweather, 412-416. Vol. 30. Computer Aided Chemical Engineering 30. London: Elsevier, 2012.
AbstractIn this paper we address the problem of uncertainty in the design and planning of a multi-period, multi-product closed loop supply chain, where the recovered products are end-of-life products that are disassembled and recycled. Uncertainty is explicitly modelled by considering customers’ demands and returns to be stochastic. A two–stage model is developed where first stage decisions concern the facility location while second stage decisions are the production planning of the supply chain. The integer L- shaped method was adopted as the solution tool and computational tests were performed on multi-period and multi-commodity networks randomly generated based on a reference case. A comparison between the proposed solution method and the straight use of the CPLEX is performed.