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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Environmental issues with the remanufacturing industry

Lindahl, Mattias, Sundin, Erik, Östlin, Johan January 2006 (has links)
Researchers often regard remanufacturing as an environmentally beneficial end-of-life option. There have been, however, few environmental measurements performed in the area. The aim of this paper is to identify general environmental pros and cons with remanufacturing. This is done through the analysis of practical examples in remanufacturing industries. Life Cycle Assessment methodology has been used for the environmental validations. The first conclusion, based on the industrial cases and the literature review, is that remanufacturing is preferable from a material resource perspective when compared with manufacturing of new products. The second conclusion is that remanufacturing is preferable from a more overarching perspective for some of the investigated cases, but it is not possible to draw any general conclusions since the companies studied are few and benefits from remanufacturing are highly context-related.
32

Centralization And Advance Quality Information In Remanufacturing

Unal, Muruvvet 01 September 2009 (has links) (PDF)
In this study, value of quality information and the eects of centralization are investigated for a reverse supply chain consisting of a remanufacturer and a collector. Used products are collected and inspected to classify them into quality groups, then they are remanufactured to meet the demand of remanufactured products. The supply of collected products and demand of remanufactured products are both price-sensitive. The uncertain quality of the collected products is revealed by an inspection process. Two quality classes are considered, and the cost of remanufacturing depends on the quality class. The main decisions are on acquisition fee for the returns, the selling price for remanufactured products, and the transfer prices of inspected products between the collector and the remanufacturer. For this environment, centralized and decentralized settings are considered and dierent models that dier in availability of quality information when the pricing decisions are made are built. We explore the value of advance quality information and eects of centralization on the optimal prices and profits via a computational study.
33

Product strategies in supply chains

Singh, Narendra 21 September 2015 (has links)
This doctoral dissertation titled "Product Strategies in Supply Chains" consists of three essays. In this dissertation, I study firms' strategic decisions regarding design of products and product lines in different supply chain contexts. I focus on firms' strategic interactions with supply chain members, including consumers and suppliers, in dynamic environments. The first essay (Chapter 2) studies how the cost structure of and information asymmetry about an OEM's in-house option affect her choice of product design quality in a decentralized supply chain where the supplier specifies contract terms. The second essay (Chapter 3) examines the effect of product returns and their potential refurbishing on intertemporal product strategy and profit of a firm facing strategic consumers. We also examine the effect of product returns on the time inconsistency problem faced by the firm. The third essay (Chapter 4) investigates the impact of competition from a third-party remanufacturer on product strategy and profit of an OEM in the presence of strategic consumers. Motivated by general perception among practitioners and the extant literature showing the competition from third-party remanufacturers as undesirable for the OEM, we specifically examine whether competition from a third-party remanufacturer is always undesirable for the OEM.
34

CAD methods to support automated De- and remanufacture assessments

Harper, Brian Davidson 12 1900 (has links)
No description available.
35

Refuse or reuse : managing the quality of returns in product recovery systems

Marshall, Sarah Elizabeth January 2012 (has links)
Increasing legislative and societal pressures are forcing manufacturers to become environmentally-conscious and take responsibility for the fate of their goods after they have been used by consumers. As a result, some manufacturers operate hybrid systems which produce new goods and recover used goods. Product recovery describes the process by which used products are returned to their manufacturers or sent to a specialised facility for recovery, before being sold on the original or a secondary market. The quality of the returned goods is a significant issue in product recovery systems as it can affect both the type of recovery and costs associated with it. Quality in product recovery systems has not been adequately studied, with many authors either ignoring the possibility of receiving lower quality returns, or assuming they are disposed of rather than recovered. However, such assumptions ignore the possibility that the firm might be able to salvage value from lower quality returns by using them for parts or materials. This thesis presents four models that investigate the importance of considering the quality of returns in the management of inventory in a product recovery system, by examining the cost-effectiveness of recovering both high quality and low quality returns. The first model is a deterministic lot-sizing model of a product recovery system. It was found that performing both high and low quality recovery reduced the sensitivity of the optimal cost to operational restrictions on the choice of decision variables. The second model is a discrete-time, periodic-review model formulated as a Markov decision process (MDP) and introduces uncertainty in demand, returns, and the quality of the returns. It was found that performing both types of recovery can lead to cost savings and better customer service for firms through an increased fill rate. The third model addresses those industries where produced and recovered goods cannot be sold on the same market due to customers’ perceptions and environmental legalisation. Using an MDP formulation, the model examines a product recovery system in which produced and recovered goods are sold on separate markets. The profitability of offering two-way substitution between these markets was investigated. It was found that offering substitution can allow firms to increase both their profits and fill rates. The fourth model examines the issue of separate markets and substitution in the continuous time domain using a semi-Markov decision process. The continuous nature of the model allows more detailed examination of the substitution decision. It was found that offering substitution can allow firms to increase their profit and in some cases also increase their fill rate. In some cases, production is performed less frequently when downward substitution can be offered, and recovery is performed less often when upward substitution can be offered. The findings of this thesis could be used to help a firm that is currently recovering high quality returns assess the cost-effectiveness of also recovering lower quality returns. Recovering low-quality items, rather than disposing of them, may allow a firm to increase the amount it recycles. The findings highlight the importance of considering the quality of returns when managing a product recovery system as they show that economic gains can be achieved by reusing rather than refusing low quality returns.
36

Profit Oriented Disassembly Line Balancing

Altekin, Fatma Tevhide 01 January 2005 (has links) (PDF)
In this study, we deal with the profit oriented partial disassembly line balancing problem which seeks a feasible assignment of selected disassembly tasks to stations such that the precedence relations among the tasks are satisfied and the profit is maximized. We consider two versions of this problem. In the profit maximization per cycle problem (PC), we maximize the profit for a single disassembly cycle given the task times and costs, part revenues and demands and station costs. We propose a heuristic solution approach for PC based on the liner programming relaxation of our mixed integer programming formulation. In the profit maximization over the planning horizon problem (PH), the planning horizon is divided into time zones each of which may have a different disassembly rate and a different line balance. We also incorporate other issues such as finite supply of discarded product, subassembly and released part inventories availability, and smoothing of the number of stations across the zones. PH is decomposed into a number of successive per cycle problems, which are solved by a similar heuristic approach. Computational analysis is conducted for both problems and results are reported.
37

Value of information in a closed loop supply chain in presence of unreliable suppliers for new product /

Vasavada, Amit. January 2009 (has links)
Thesis (M.S.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Systems Science and Industrial Engineering, 2009. / Includes bibliographical references.
38

A Simulation-Based Decision Support Tool for Circularity : Remanufacturing of an Electric Machine Case Study

Pérez Tay, Mayari January 2023 (has links)
Over the last years, environmental concerns have grown regarding the pressure manufacturing activities exerts on natural resources. Many materials have been classified by the EU as scarce, rare earth elements found in magnets are amongst critical materials with high supply risk. Furthermore, this has led to increasing material costs and disruptions in the supply chain. Efforts towards increased electrification are reliant on these and other critical materials. Electric machines that power a battery electric vehicle (BEV), are vulnerable to this price variations as magnets represent high material costs. Circular business strategies present the opportunity to decouple value generation from resource use, providing a cost effective way to support net zero targets. Legislation is toughening up, increasing original equipment manufacturer (OEM) extended responsibility, which might lead to mandatory product returns that require end of life (EOL) treatment. Therefore, OEMs need a systematic way to explore EOL design strategy combinations, that can quantify the impact of a circular business model, which considers product returns and remanufacturing activities. Thus preparing to meet greener demands from customers, government and society in general. This thesis work focuses on quantifying economic and environmental factors, of circular design strategies, through simulations tools to support EOL decisions at component level. Scania’s electric machine (EM) has been used as a case study for the simulation, collecting expert input from 6 different groups. Anylogic Professional software (8.8.1 version) has been used to set up a model that represents a closed loop supply chain. An optimization experiment has been conducted, to find the cost minimum design strategies for the EM’s parts. It shows redesigning part 1 and one entire module for easy reuse minimizes overall costs. This generates economic and environmental benefits in the form of savings compared to business as usual (linear) scenario; cost savings amount to 17.7%, CO2 equivalent emissions savings to 38.7% (cradle-to-gate), and virgin material saved (from extraction) to 14.7%. The results of this work are intended to provide data supporting circular initiatives, for Scania and potentially other OEMs, for better decision making.
39

Analysis of decision-making in closed-loop supply chains

Lee, Chanjoo 08 July 2011 (has links)
Closed-loop supply chains (CLSCs) that integrate the activities for reclaiming residual values in postconsumer products with the traditional forward supply chain activities are important from financial and environmental perspectives. This thesis develops models and analyses on three topics novel to the field of CLSC research with a goal of advancing knowledge about effective decision-makings in CLSCs. In the first part of the thesis, we study joint control of stochastic forward and stochastic reverse material flows in CLSCs. With an application to a CLSC where postconsumer products are collected for warranty service purposes, we demonstrate that the benefit of coordinating two production activities could be significant. We develop a model that can be used to obtain an effective inventory control policy for coordinating forward and reverse material flows. Through Monte Carlo simulation and global sensitivity analysis, we identify major influential factors that affect system's warranty cost savings performance. The results indicate that joint control of forward and reverse material flows greatly improves warranty cost savings performance as well as system's robustness to uncertainties. The second part of the thesis develops a differential game model for characterizing decentralized time-varying competitive decision-making in a CLSC. The differential game model is particularly useful for studying time-varying interactive decision-making in CLSCs that involve many stakeholders who pursue different objectives in forward and reverse production activities. We identify optimal prices and production strategies that evolve over time under fluctuating market demand. Also, the model provides a quantitative scheme that can be used to obtain an efficient apportionment of product recovery processes. The third part of the thesis describes the relationship among consumers' risk-aversion, product cannibalization of new products by remanufactured products, and growth of CLSCs through price optimization models. Whereas price is one of the most effective variables for managing market demand, previous CLSC research has mainly focused on operational problems without paying much attention on the interface between CLSCs and markets. We develop models that jointly determine optimal prices in forward and reverse channels considering consumers' willingness-to-pay (WTP) for remanufactured products, consumers' willingness-to-accept (WTA) for a buyback price, and consumers' risk aversion to uncertain quality perceptions. The results show that consumers' active participation in CLSC is an important factor for the viability and growth of a CLSC. Also, we show that companies can benefit from product remanufacturing although it may be accompanied by production cannibalization.
40

Determining the environmnetal impact of disposal, recycling and remanufacturing strategies

Govetto, Sophie 06 December 2007 (has links)
In the past few decades, globalization has led to a world economy with unbounded consumption. In addition to the consequential impoverishment of natural resources, this large consumption produces copious amounts of waste and requires high energy use. Proper end-of-life strategies can help to reduce the global impact of these inefficiencies. The objective of this thesis is to demonstrate, through life-cycles analyses of an automotive transfer case and a gear, the positive environmental impact of remanufacturing strategies compared to recycling and disposal end-of-life strategies. In this study, the energy consumption, the air emissions and the wastes resulting from the entire supply chain s engineering processes will be quantitatively evaluated through calculations and also industrial or governmental data. In disposal end-of-life strategies, the analysis will begin with the ore mining phase, will go through material refining and processing; and eventually end with the final parts machining. In recycling scenarios and remanufacturing scenarios, the analysis will begin with the used material collection, will go through material s reprocessing or refurbishing and will finally end with the new or renewed parts machining. This study will show the significant impact of high energy consumption processes such as electrolysis of aluminum and metal melting. It will also show how shipping and collection phases can dramatically change or annihilate the advantage of sustainable reuse scenarios depending on the sorting strategies adopted in the supply chain. To conclude, the goal of this research is to demonstrate how remanufacturing strategies can reduce the energy consumption, air emissions and waste. This thesis will also show how inappropriate supply chain management can negate the impact of these savings.

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