No abstract

Due to the rapid advances in technology, increasing consumption rates and continuously released new products lead to shorter product life cycles, putting the sustainability issue under the spotlight. This, in turn, creates an unmanageable amount of waste that needs immediate care. Electrical and electronic equipment is one of the major contributors to this waste given that millions of metric tons of electronic waste are generated across the world each year, and only an insignificant percentage of which is recycled. The recycling of printed circuit boards, which accounts for considerable monetary value in waste electrical and electronic equipment has long been ignored due to the serious challenges in collection, dismantling, and recycling processes. In this study, the open-loop and closed-loop supply chain involving circular economy objectives is designed in order to increase the recyclability of valuable metals including gold, silver, copper, and palladium. In this regard, a mixed-integer linear programming model is developed that aims at maximizing the profit from the flow in the supply chain network. The model was tested with actual data obtained from a printed circuit board firm in Turkey that aimed optimal distribution in its supply chain. The results reveal that the product/material flows, which have an impact on the revenues, were among the most important factors affecting profitability. Considering the circular economy objectives, the revenue obtained in the hybrid open-loop and closedloop supply chain is predominantly provided by the reuse and repair activities. In addition, the boundaries of the proposed model are tested with sensitivity analyses and the results are discussed extensively with conclusions on managerial implications.

During the Covid-19 outbreak, different types of vaccines have been produced and tested in different countries. However, the produced vaccines have different features from each other, and governments are undergoing a decision process for vaccine selection. Criteria such as side effects of vaccines, supply chain processes, storage conditions, costs and perception on people play a crucial role in decision-making. In this study, vaccine selection is considered in an analytical framework. In this context, we focus on vaccine selection using the interval-valued intuitionistic fuzzy VIKOR method (VIseKriterijumska Optimize Kompromisno Resenje), one of the multi-criteria decision-making methods. In addition, interval valued intuitionistic fuzzy numbers (IVIFN) have been integrated into the VIKOR method to eliminate the uncertainty in decision processes. First, the concept, comparison, and distances of IVIFNs are briefly presented in the first section. The extension classical VIKOR approach is then developed to address vaccine selection problem with IVIFNs, and its significant aspect is that it can completely accept the finite justification of decision-makers as a real progress in decision-making. In this study, the applicability of the interval-valued intuitionistic VIKOR (IVIFV) method to evaluate the vaccines produced for the covid-19 outbreak was discussed. With the IVIFV method, the performances of the vaccines based on various criteria were evaluated and a ranking is represented among the vaccines accordingly.

Due to the rapid advances in technology, increasing consumption rates and continuously released new products lead to shorter product life cycles, putting the sustainability issue under the spotlight. This, in turn, creates an unmanageable amount of waste that needs immediate care. Electrical and electronic equipment is one of the major contributors to this waste given that millions of metric tons of electronic waste are generated across the world each year, and only an insignificant percentage of which is recycled. The recycling of printed circuit boards, which accounts for considerable monetary value in waste electrical and electronic equipment has long been ignored due to the serious challenges in collection, dismantling, and recycling processes. In this study, the open-loop and closed-loop supply chain involving circular economy objectives is designed in order to increase the recyclability of valuable metals including gold, silver, copper, and palladium. In this regard, a mixed-integer linear programming model is developed that aims at maximizing the profit from the flow in the supply chain network. The model was tested with actual data obtained from a printed circuit board firm in Turkey that aimed optimal distribution in its supply chain. The results reveal that the product/material flows, which have an impact on the revenues, were among the most important factors affecting profitability. Considering the circular economy objectives, the revenue obtained in the hybrid open-loop and closed-loop supply chain is predominantly provided by the reuse and repair activities. In addition, the boundaries of the proposed model are tested with sensitivity analyses and the results are discussed extensively with conclusions on managerial implications.

With the technological change and development in recent years, the market shares of li-on batteries, which provide energy efficiency and cost effectiveness, is getting up rapidly. Increasing demand for li-ion batteries used in energy storage, consumer electronics and electric vehicles negatively affects the raw material supply. Materials such as lithium, cobalt and graphite, which have an important place in the production of li-on batteries, are very rare in the market and the countries where these minerals are extracted are quite limited. In addition, many problems arise in the supply chain processes due to the trade policies of these countries. Besides, the environmental and social impacts that occur with the increasing demand for li-on batteries stand out as another problem. In this study, an analytical approach to recycling li-on batteries is presented with a circular economy perspective. With a recycling framework within the current li-on battery life cycle process, we focused on the challenges that arise in this process. From the circular economy perspective, challenges of the recycling process of lion batteries are prioritized by examining their technological, environmental, social and economic dimensions. AHP method is used to prioritize challenges by weighing them over different dimensions. Also, Pythagoras fuzzy numbers are integrated in-to AHP method to overcome uncertainty. In the last part of the study, the results are supported with the managerial implications for li-on battery recycling.