The Experts below are selected from a list of 69477 Experts worldwide ranked by ideXlab platform
Hsiao-fan Wang - One of the best experts on this subject based on the ideXlab platform.
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a closed loop logistic model with a spanning tree based genetic algorithm
Computers & Operations Research, 2010Co-Authors: Hsiao-fan WangAbstract:Due to the problem of global warming, the green supply chain management, in particular, closed-loop logistics, has drawn the attention of researchers. Although there were logistics models that were examined in the literatures, most of them were case based and not in a closed-loop. Therefore, they lacked generality and could not serve the purposes of recycling, reuse and recovery required in a green supply chain. In this study, the integration of forward and reverse logistics was investigated, and a generalized closed-loop model for the logistics planning was proposed by formulating a cyclic logistics network problem into an integer linear programming model. Moreover, the decisions for selecting the places of manufactories, distribution centers, and Dismantlers with the respective operation units were supported with the minimum cost. A revised spanning-tree based genetic algorithm was also developed by using determinant encoding representation for solving this NP model. Numerical experiments were presented, and the results showed that the proposed model and algorithms were able to support the logistic decisions in a closed-loop supply chain efficiently and accurately. Statement of scope and purposes: This study concerns with operations of 3R in the green supply chain logistics and the location selection optimization. Based on 'cradle to cradle' principle of a green product, a ''closed-loop'' structure of a network was proposed in order to integrate the environmental issues into a traditional logistic system. Due to NP-hard nature of the model, a Genetic Algorithm, which is based on spanning tree structure was developed. Test problems from the small size for accuracy to the large scale for efficiency have been demonstrated with comparison. The promising results have shown the applicability of the proposed model with the solution procedure.
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A closed-loop logistic model with a spanning-tree based genetic algorithm
Elsevier, 2010Co-Authors: Hsiao-fan WangAbstract:[[abstract]]\ Due to the problem of global warming, the green supply chain management, in particular, closed-loop logistics, has drawn the attention of researchers. Although there were logistics models that were examined in the literatures, most of them were case based and not in a closed-loop. Therefore, they lacked generality and could not serve the purposes of recycling, reuse and recovery required in a green supply chain. In this study, the integration of forward and reverse logistics was investigated, and a generalized closed-loop model for the logistics planning was proposed by formulating a cyclic logistics network problem into an integer linear programming model. Moreover, the decisions for selecting the places of manufactories, distribution centers, and Dismantlers with the respective operation units were supported with the minimum cost. A revised spanning-tree based genetic algorithm was also developed by using determinant encoding representation for solving this NP model. Numerical experiments were presented, and the results showed that the proposed model and algorithms were able to support the logistic decisions in a closed-loop supply chain efficiently and accurately.[[fileno]]2020402010050[[department]]工工
Jinho Park - One of the best experts on this subject based on the ideXlab platform.
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management status of end of life vehicles and characteristics of automobile shredder residues in korea
Waste Management, 2004Co-Authors: Kiheon Kim, Hyuntae Joung, Hoon Jae Nam, Yongchil Seo, John Hee Hong, Taewook Yoo, Bongsoo Lim, Jinho ParkAbstract:An end-of-life vehicle (ELV) is dismantled to recover and recycle any re-usable parts, then shipped to the shredding facility for further recovery of iron with any remaining Automobile Shredder Residue (ASR) to be considered as wastes and to be disposed of by either thermal treatment or landfill. Overall ELVs management status in Korea, including recycling resulting from the dismantling processes, was surveyed using some questionnaires given to Dismantlers and other available information to provide some feasible means for future treatment. The averaged recycle rate in the dismantling stage showed a value of 44% and the rest of an ELV was then compressed and transported to shredding companies to recover mainly the iron content which averaged 38.7% of the mass of a new vehicle. The non-ferrous metals such as copper, antimony, zinc and aluminum accounted for only 1.5%. The Shredder dusts (SDs) were found to be composed of light and heavy fluffs and soil/dust and amounted to 15.8% based on the mass of a new vehicle. Dumping of fluff and inorganic residues into a landfill site, however, will be restricted when new regulations are implemented to reduce the disposal amount to less than 5% of a new car as done in European countries and Japan. The detailed characteristics of SDs were investigated to provide an idea of how to treat them in order to meet a future expected enforcement.
Simon J Boulton - One of the best experts on this subject based on the ideXlab platform.
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rtel1 dismantles t loops and counteracts telomeric g4 dna to maintain telomere integrity
Cell, 2012Co-Authors: Jeanbaptiste Vannier, Visnja Pavicickaltenbrunner, Mark I R Petalcorin, Hao Ding, Simon J BoultonAbstract:Summary T loops and telomeric G-quadruplex (G4) DNA structures pose a potential threat to genome stability and must be dismantled to permit efficient telomere replication. Here we implicate the helicase RTEL1 in the removal of telomeric DNA secondary structures, which is essential for preventing telomere fragility and loss. In the absence of RTEL1, T loops are inappropriately resolved by the SLX4 nuclease complex, resulting in loss of the telomere as a circle. Depleting SLX4 or blocking DNA replication abolished telomere circles (TCs) and rescued telomere loss in RTEL1 −/− cells but failed to suppress telomere fragility. Conversely, stabilization of telomeric G4-DNA or loss of BLM dramatically enhanced telomere fragility in RTEL1-deficient cells but had no impact on TC formation or telomere loss. We propose that RTEL1 performs two distinct functions at telomeres: it disassembles T loops and also counteracts telomeric G4-DNA structures, which together ensure the dynamics and stability of the telomere.
Aweewan Mangmeechai - One of the best experts on this subject based on the ideXlab platform.
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Life-cycle greenhouse gas and value chain of end-of-life vehicle management in Thailand
Clean Technologies and Environmental Policy, 2020Co-Authors: Aweewan MangmeechaiAbstract:The management of many products during their end-of-life stage has not been addressed fully in Thailand. Today, the owners of dismantling facilities and car repair shops are managing end-of-life vehicles (ELVs) increasingly. This ELV market system involves recovering ELVs’ valuable materials and components. At present, information on ELVs’ current status is limited, and this lack of information will lead eventually to managing ELVs improperly. This paper presents an overview of the current status of ELV management in Thailand and proposes an appropriate way to improve it. The objectives of this study are to: (1) estimate the number and distribution of passenger cars (four wheels, but less than seven seats); (2) understand ELV stakeholders’ geographic locations to show the scarcity of ELV hotspots, Dismantlers, and recycling industry facilities;(3) study the life cycle of greenhouse gas emissions (LCA GHGs) and the value chain in ELV management; and (4) provide recommendations for an ELV management policy. Field data were collected from key stakeholders in the supply chain. The results showed that a significant number of ELVs are discarded annually, and very few ELVs were sent to recycling facilities. ELVs’ LCA GHGs were estimated to be 540.9–1344 kg CO_2e/car. In addition, the value added in ELV management could be in the range of 58–92 million THB million a year (USD 1.7–2.8 million) if these ELV parts are recycled, and recycling ELVs could reduce CO_2e emissions by 92,767–159,952 tons. Graphic abstract
Victoria H Arrandale - One of the best experts on this subject based on the ideXlab platform.
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exposure of canadian electronic waste Dismantlers to flame retardants
Environment International, 2019Co-Authors: Linh V Nguyen, M Diamond, Marta Venier, William A Stubbings, Kevin Romanak, Lola Bajard, Lisa Melymuk, Liisa M Jantunen, Victoria H ArrandaleAbstract:Abstract Exposure of e-waste workers to eight halogenated and five organophosphate ester flame retardant chemicals (FRs) was studied at a Canadian e-waste dismantling facility. FR concentrations were measured in air and dust samples collected at a central location and at four work benches over five-24 hour periods spanning two weeks. The highest concentrations in air from workbenches were of BDE-209 (median 156 ng m−3), followed by Tris(2-chloroethyl) phosphate (TCEP, median 59 ng m−3). Dust concentrations at the workbenches were higher than those measured at the central location, consistent with the release of contaminated dust during dismantling. Dust concentrations from the workbenches were also dominated by BDE-209 (median 96,300 ng g−1), followed by Triphenyl phosphate (TPhP, median 47,000 ng g−1). Most FRs were in coarse particles 5.6–18 μm diameter and ~30% were in respirable particles (
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occupational exposure to flame retardants among canadian e waste Dismantlers
ISEE Conference Abstracts, 2018Co-Authors: Victoria H Arrandale, Linh V Nguyen, Marta Venier, William A Stubbings, Kevin Romanak, Lisa Melymuk, Liisa M Jantunen, Jiehong Guo, M DiamondAbstract:Background: The mass of e-waste produced globally is growing dramatically. Workers dismantling and recycling e-waste are exposed to many hazards, including flame retardants (FRs), that are added to...