The Experts below are selected from a list of 304452 Experts worldwide ranked by ideXlab platform
Luis Arroja - One of the best experts on this subject based on the ideXlab platform.
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cork stoppers supply chain potential scenarios for environmental impact reduction
Journal of Cleaner Production, 2016Co-Authors: Martha Demertzi, Rui Pedro Silva, Ana Claudia Dias, Belmira Neto, Luis ArrojaAbstract:Abstract The purpose of the present study is to evaluate the environmental impacts deriving from the Production of natural cork stoppers in Portugal, in order to identify the most significant Stages and processes (hotspots) and to suggest improvement actions and alternative scenarios. Life Cycle Assessment (LCA) methodology is used by applying a cradle-to-bottling approach. This approach includes the Stages of forest management (not considered in related LCA studies), cork preparation, natural cork stoppers Production, finishing and distribution to the bottling locations. The results show that the forest management Stage has the largest contribution to the environmental impact of natural cork stoppers in the majority of the impact categories. More specifically, the greatest influence derives from the operations of pruning and spontaneous vegetation cleaning. Additionally, the preparation Stage and the Production Stage influence two impact categories each, while the finishing Stage is the hotspot in one impact category. These contributions are mainly caused by the energy requirements of these Stages. The total environmental impacts may be decreased by 3%–65% if maintenance pruning operations are not performed and simultaneously cleaning operations are undertaken by rotary mowers instead of disc harrows in the forest management Stage. Changes in the Production Stage, such as decreasing the transport distance between the preparation and the Production factory or the use of a combination of manual and mechanical punching, do not show great influence in the total environmental impact.
Martha Demertzi - One of the best experts on this subject based on the ideXlab platform.
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cork stoppers supply chain potential scenarios for environmental impact reduction
Journal of Cleaner Production, 2016Co-Authors: Martha Demertzi, Rui Pedro Silva, Ana Claudia Dias, Belmira Neto, Luis ArrojaAbstract:Abstract The purpose of the present study is to evaluate the environmental impacts deriving from the Production of natural cork stoppers in Portugal, in order to identify the most significant Stages and processes (hotspots) and to suggest improvement actions and alternative scenarios. Life Cycle Assessment (LCA) methodology is used by applying a cradle-to-bottling approach. This approach includes the Stages of forest management (not considered in related LCA studies), cork preparation, natural cork stoppers Production, finishing and distribution to the bottling locations. The results show that the forest management Stage has the largest contribution to the environmental impact of natural cork stoppers in the majority of the impact categories. More specifically, the greatest influence derives from the operations of pruning and spontaneous vegetation cleaning. Additionally, the preparation Stage and the Production Stage influence two impact categories each, while the finishing Stage is the hotspot in one impact category. These contributions are mainly caused by the energy requirements of these Stages. The total environmental impacts may be decreased by 3%–65% if maintenance pruning operations are not performed and simultaneously cleaning operations are undertaken by rotary mowers instead of disc harrows in the forest management Stage. Changes in the Production Stage, such as decreasing the transport distance between the preparation and the Production factory or the use of a combination of manual and mechanical punching, do not show great influence in the total environmental impact.
William B Hetzel - One of the best experts on this subject based on the ideXlab platform.
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a dynamic model for requirements planning with application to supply chain optimization
Operations Research, 1998Co-Authors: Stephen C Graves, David B Kletter, William B HetzelAbstract:This paper develops a new model for studying requirements planning in multiStage Production-inventory systems. We first characterize how most industrial planning systems work, and we then develop a mathematical model to capture some of the key dynamics in the planning process. Our approach is to use a model for a single Production Stage as a building block for modeling a network of Stages. We show how to analyze the single-Stage model to determine the Production smoothness and stability for a Production Stage and the inventory requirements. We also show how to optimize the tradeoff between Production capacity and inventory for a single Stage. We then can model the multiStage supply chain using the single Stage as a building block. We illustrate the multiStage model with an industrial application, and we conclude with some thoughts on a research agenda.
Tarik Aouam - One of the best experts on this subject based on the ideXlab platform.
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extending the strategic safety stock placement model to consider tactical Production smoothing
European Journal of Operational Research, 2019Co-Authors: Kunal Kumar, Tarik AouamAbstract:This paper extends strategic safety stock placement models under the guaranteed service approach (GSA) to incorporate tactical Production smoothing. We propose a model to jointly optimize Production capacity, Production smoothing, and service times between all Stages in the supply chain. Analysis of the model leads to several interesting findings. First, for certain service times, Production smoothing is desirable to reduce both capacity and inventory costs. Second, inventory cost at a Production Stage is non-monotonous in its net service time and consequently quoting a large service time may increase costs at both the Production Stage and its customers. Third, safety stocks can be pooled at downstream Stages only when Production is not smoothed, while Production smoothing necessitates holding safety stocks. The formulated problem is solved using a dynamic program and numerical experiments are conducted based on a real-world instance from the literature. Through these experiments, we show that integrating Production smoothing in GSA models results in considerable savings, especially when capacity costs are neither too high nor too low relative to holding costs.
Yingdong Lu - One of the best experts on this subject based on the ideXlab platform.
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a Production inventory model for a push pull manufacturing system with capacity and service level constraints
Production and Operations Management, 2012Co-Authors: Feng Cheng, Markus Ettl, Yingdong LuAbstract:We study a hybrid push–pull Production system with a two-Stage manufacturing process, which builds and stocks tested components for just-in-time configuration of the final product when a specific customer order is received. The first Production Stage (fabrication) is a push process where parts are replenished, tested, and assembled into components according to product-level build plans. The component inventory is kept in stock ready for the final assembly of the end products. The second Production Stage (fulfillment) is a pull-based assemble-to-order process where the final assembly process is initiated when a customer order is received and no finished goods inventory is kept for end products. One important planning issue is to find the right trade-off between capacity utilization and inventory cost reduction that strives to meet the quarter-end peak demand. We present a nonlinear optimization model to minimize the total inventory cost subject to the service level constraints and the Production capacity constraints. This results in a convex program with linear constraints. An efficient algorithm using decomposition is developed for solving the nonlinear optimization problem. Numerical results are presented to show the performance improvements achieved by the optimized solutions along with managerial insights provided.
