The purpose of this paper is to propose a framework to identify all the feasible disassembly sequences for a multi‐component product and to find an optimal disassembly…
The purpose of this paper is to propose a framework to identify all the feasible disassembly sequences for a multi‐component product and to find an optimal disassembly sequence, according to specific criteria such as cost, duration, profit, etc.
Taking into account topological and geometrical constraints of a product structure, an AND/OR disassembly graph is built. Each graph node represents a feasible subassembly. Two nodes i and j are connected by an arc (i, j), called a transition, if the subassembly j can be obtained from the subassembly i by removing one or several connectors. Constraint programming approach is used to generate the feasible subassemblies and related transitions.
If a cost zij is incurred to perform a transition (i, j), an optimal disassembly sequence can be generated for a given subassembly, using the shortest path algorithm or a linear programming model.
The proposed approach performs very well compared to other approaches published in the literature, even when applied to products requiring parallel disassembly and including a large number of parts.
This approach has been successfully applied to assess the wheelchair maintainability at the design stage and will be implemented in CAD systems. One other application, regarding the disassembly process and total revenue maximization for product recycling, is now under consideration.
Applying constraint programming to efficiently generate the set of the feasible subassemblies constitutes the main contribution in this paper. This process is the hardest step in the disassembly sequencing problem.
The Renewable Energy Directive (RED) is a specific example of life cycle assessment (LCA) applied to legislative measures that have far‐reaching implications for economic…
The Renewable Energy Directive (RED) is a specific example of life cycle assessment (LCA) applied to legislative measures that have far‐reaching implications for economic operators. This paper aims to analyze LCA limitations for biofuels based on RED from an environmental accounting perspective.
LCA limitations are identified on the basis of a literature review and illustrated in the specific context of RED. The limitations encountered within the study were classified into two categories: lack of data, and lack of standards. From this perspective, the LCA‐based problems and their implication and possible improvements in the RED context are discussed.
The study identifies that the absence of an environmental accounting that could provide periodic enterprise‐specific information is a significant cause of limitations of LCA as a decision‐supporting tool within RED. In turn, environmental accounting approaches address a number of initiatives that are not systematically linked with LCA research. The paper recommends that RED should provide rules to address enterprise‐specific data in addition to other methodological approaches to overcome problems already discussed in the extant literature. This would enable RED to provide economic incentives more effectively and promote the application of environmental accounting systems in companies with higher quality data for LCA applications.
This paper explains how LCA applications could be improved by the introduction of environmental accounting systems and how RED could be more effective by considering environmental accounting.