Embalagens de vidro pós-consumo no sistema de coleta seletiva: o caso da cidade de Londrina

Purpose: This article presentes the results of an in-depth and contextualized study on the problems in the commercialization of glass containers sent to the selective collection system of the city of Londrina-PR, Brazil.Design: The methodological strategy was the triangulation of sources of evidence desiring to understand the situational characteristics, as well as the operational and environmental challenges faced by the local actors involved, especially the cooperatives. Quantitative and qualitative study case using primary and secondary data collection from multistakeholders.Findings: The data collected here allow us to conclude that vitreous materials have demonstrated difficult commercialization processes and are among those materials that are economically less interesting for cooperatives, intensifying the high social fragility of cooperates.Practical implications: The search for solutions to environmental and economic problems caused by the high generation of municipal solid waste in Brazil still have strong deficiencies in methodologies and technologies. Social implications: How the reverse logistics of vitreous packaging is operationalized has increased public financing with this type of material, since the sales price obtained by waste pickers does not corroborate the economic support of cooperative enterprises.Originality/value: This study allows to advance in the explanation and description of the way of structuring the reverse chain of vitreous packaging, especially in medium-sized municipalities in the inland.Keywords: post-consumption; packaging; glass; recycling; selective collection

FORMATION OF MATERIAL FLOWS IN A LOGISTIC SYSTEM WITH FEEDBACK

The study is devoted to solving the problem of forming reverse material flows with the use of circular economy processes, which will achieve maximum efficiency of the logistics system.The existing linear model of the economy is not environmentally oriented, as it constantly requires the involvement of additional primary resources, which, passing through the man-made system, produce a large amount of waste. The concept of circular economy is based on the principles and goals of the concept of sustainable development and emphasizes the need to close logistics systems, the creation of logistics systems with feedback. The tool for the implementation of the concept are closed logistics chains, which include direct and reverse material flows.Participants and the processes used in the circular economy model proposed by the Ellen McArthur Foundation were used to create a model of a feedback logistics system that includes complete closed logistics chains. According to this model, the main participants in closed chains are: resource provider, parts manufacturer, product manufacturer, service provider, consumer/user, collection center), repair center, sort center, utilization center.Within a complete closed supply chain, the direct chain starts with the natural environment and the supplier of resources and ends with the consumer/user of the product, the reverse chain begins with the consumer/user of the product and ends with the recycling center and the natural environment.Among the processes of the circular economy to highlight the processes related to reverse logistics and involved in the organization of reverse flows to create feedback in a closed logistics chain: recover, recycle, refurbish, remanufacture, repurpose, repair, reuse. These processes, which can be called circular, create logistics loops between the participants in the logistics chain, providing feedback in closed logistics chains.The article presents a graphical model of the logistics system with feedback using circular processes; created an economic-mathematical model of the logistics system with feedback.Keywords: circular process; closed logistics chain; logistics loop; reverse material flow.

The Reverse Logistics of Cross-Border e-Tailing in Europe

The purpose of this article is to develop a research agenda to analyze the potential environmental implications of the reverse logistics involved in the B2C element of cross-border clothing e-tailing. Based on a combination of literature review and primary case study data from five major clothing retailers and two logistics service providers in Sweden, a categorization of cross-border reverse chain possibilities is developed. Seven reverse chain types are identified and it is shown that all of the five retailers use multiple reverse chain types. The results are subsequently used to highlight research gaps and define a future research agenda which will enable a more complete environmental analysis of the impacts of online clothes shopping incorporating both the outward and reverse elements.

Key Issues and Challenges of a Sustainable Closed Loop Supply Chain

Being tied with sustainability and due to the emergence of various environmental threats, closed loop supply chain (CLSC) has received huge attention recently. Dealing with both forward and reverse chain simultaneously, closed loop supply chain plays the key role as an enabler for sustainability. In this paper the gradual evolution of supply chain, the concept of sustainability, sustainable supply chain, incentives and different dimensions of sustainability and closed loop supply chain, issue and challenges such as recovery options, product acquisition, uncertainty, supplier selection, etchave been discussed.

Applying Fuzzy Multiobjective Integrated Logistics Model to Green Supply Chain Problems

The aim of this paper is attempting to explore the optimal way of supply chain management within the domain of environmental responsibility and concerns. The background of this research involves the issue of green supply chain management (GSCM) and the concept of the multiobjective integrated logistics model. More specifically, in this paper, we suggest the fuzzy multiobjective integrated logistics model with the transportation cost and demand fuzziness to solve green supply chain problems in the uncertain environment which is illustrated via the detailed numerical example. Results and the sensitivity analysis of the numerical example indicate that when the governmental subsidy value increased the profits of the reverse chain also increased. The finding shows that the governmental subsidy policy could remain of significant influence for used-product reverse logistics chain.

An Operational Framework For Reverse Supply Chains

In this paper, we present a framework for reverse supply chains. We identify four managerial drivers in the reverse chain as Facilities, Handling, Ease of Access, and Information. We explore the impact of each of these drivers upon the effectiveness and performance of the overall reverse chain via a survey of supply chain managers. We present the results of the survey and conclude with managerial implications derived from the survey results. The field interviews have been supplemented with survey results. The results indicate that the firms, that have reverse supply chain as a strategic priority providing a responsive and effective transportation network and that have an easy return policy, are more likely to have the most reliable reverse supply chain. The results also indicate that reverse supply chain matters the most at the late growth stage of the product life.

Exit Frequency Matrices for Finite Markov Chains

Consider a finite irreducible Markov chain on state spaceSwith transition matrixMand stationary distribution π. LetRbe the diagonal matrix of return times,Rii= 1/πi. Given distributions σ, τ andk∈S, the exit frequencyxk(σ, τ) denotes the expected number of times a random walk exits statekbefore an optimal stopping rule from σ to τ halts the walk. For a target distribution τ, we defineXτas then×nmatrix given by (Xτ)ij=xj(i, τ), whereialso denotes the singleton distribution on statei.The dual Markov chain with transition matrix=RM⊤R−1is called thereverse chain. We prove that Markov chain duality extends to matrices of exit frequencies. Specifically, for each target distribution τ, we associate a unique dual distribution τ*. Let$\rX_{\fc{\t}}$denote the matrix of exit frequencies from singletons to τ* on the reverse chain. We show that$\rX_{\fc{\t}} = R (X_{\t}^{\top} - \vb^{\top} \one)R^{-1}$, wherebis a non-negative constant vector (depending on τ). We explore this exit frequency duality and further illuminate the relationship between stopping rules on the original chain and reverse chain.