The research object of this thesis are reuse CLSC. In Chapter 2 and Section 3.2, it was argued that: 1) RL and CLSC are subjects of study in the Operations Management area that still need important amounts of exploration and conceptualization; 2) Within this general exploration context, reuse aspects have been under-researched in the newly emerging …eld of closed-loop supply chains, especially when compared to other types of CLSC (remanufacturing, commercial returns). Given the novelty of reuse CLSC topic, conceptualization of the reuse phenomena from real data coming from the …eld appear to be necessary. The reserch process started with …eld studies intending to acquire deeper insights into the reuse processes.The results from the conceptualization process are presented in Chapters 4 and 5 of this dissertation. The conceptual model that is put forward there is generated through an inductive process (bottom- up approach) based on several case studies that have been carried out in real industrial settings, in close contact with several partner companies or organizations (Figure 3-4) Case Study 1 (Industrial and Medical Gases, IMG) and Case Study 2 (Liqui…ed Petroleum Gases, LPG) had an exploratory nature and enabled to identify the main managerial issues that are are related with reuse CLSC. The concepts and ideas generated in Cases 1 and 2 were afterwards con…rmed and re…ned with cases 3, 4, 5 and 6 (and also with evidence coming from literature). The four con…rmatory case studies enabled to ratify the emerging theory stemming from the two …rst case studies, to rede…ne the scope of this theory (that encompasses three di¤erent categories of reusable articles (such as reusable products, RP)) and to sharpen the concepts and ideas included in the conceptual model. The model was …nally validated by managers involved in
some of the companies that had been analyzed during the case studies.
The …rst case study (Case Study 1: Medgas) is partially based on the past professional experience of the PhD candidate as logistics manager in the medical branch of Air Liquide Spain. In addition, some interaction was also established with the main competitor of Air Liquide Spain (Carburos Metálicos) in the industrial and medical gases market. This second interaction for case study 1 came to con…rm that the problems associated with cylinder reuse observed in Air Liquide were not company-speci…c, but common to other companies operating in the same sector.
The second case study was the result of a one-year research project conducted in Repsol GLP, the liquie…ed petroleum gases (LPG) branch of Repsol group in Spain. The managerial issues observed in Case Study 1 were also observed in the Repsol case. The complexities arising in both cases were not linked to the product but to the reuse of product containers (cylinders). Cases 3, 4, 5 and 6 were carried out during a research visit in the Netherlands (Erasmus University Rotterdam) and enabled to extend the emerging managerial model to di¤erent types of reusable articles, which resulted in the typology which is presented in Chapter 4.
After the conceptualization phase, the main managerial issues arising in reuse CLSC had been identi…ed. The solutions proposal stage was then addressed. Part of the solutions proposed are based in purely quantitative modelling methods, as shown in Chapter 6.
Therefore, in the research trajectory described in this dissertation, most phases of whole process for generating scienti…c knowledge (Fig. 3-3) have been accomplised. More precisely, throughout the PhD trajectory the conceptualization, modelling and solving phases have been undergone. The validation phase has only been partially adressed through model validation by industrial practitioners. It is interesting to remark that di¤erent stages in the process of scienti…c knowledge generation have been adressed with this thesis. Each stage required its own methods, as explained in section 3.3: at …rst, case study research was used, as deeper insights on the research problem were required . Once the real problem had been modellized and structured, it was possible to formulate and solve the MILP models that will be presented in Section 6 (quantitative modelling). A complementary research technique used throughout all the PhD trajectory is systematic literature review.
Chapter 4
Reusable articles: a typology
grounded on case studies
4.1
Introduction
In section 3.1 the scope of this thesis was de…ned and the research problem at hand was positioned among the related work. The research problem sharpening process showed up that, in spite of the contribution of reuse practices to the environmental and economical sustainability of production and distribution systems, reuse closed-loop supply chains (CLSC) have not been widely researched for the moment. From this chapter onwards, we start to bridge this gap by proposing the di¤erent puzzle pieces that make up the management model for reusable articles presented as the overall research goal of this thesis.
In this chapter, the core cornerstone of the management model is adressed. More speci…cally, the reusable articles term is de…ned, the characteristics of reusable articles are identi…ed and a typology integrating di¤erent categories of articles (transport items, packaging materials, tools) is proposed. This results are grounded in set of case studies carried out in real industrial settings, which are also presented within this chapter.
Chapter 5 builds on the emerging theory stemming from chapter 4 and presents additional building blocks that are added up to the management model (common problems found in reuse CLSC, basic information (metrics), management issues, solutions proposal). The results of chapter 5 are also partially based on the case studies presented here.
Chapter 4 and chapter 5, considered as a whole, constitute the above-mentioned general and comprehensive conceptual model for the management of CLSC of reusable articles. Later on, in chapter 6, the focus will be narrowed to a particular type of solutions in the general model in order to quantitatively analyze its e¤ects on cost performance of the closed-loop system.
In Chapter 4, the speci…c objectives are:
To de…ne the reusable articles term and to propose a standard terminology in the reusable articles …eld.
To build a typology for reusable articles that integrates under the same term three di¤erent articles categories. Combining several classes under the same concept enables us to extend results obtained for one type of reusable articles to the other categories.
To identify and characterize the common features that distinguish reuse CLSC from other types of CLSC
To identify the di¤erences existing between the di¤erent categories. The di¤erences enable to establish the boundaries for results generalization among categories.
To characterize di¤erent types of reusable articles networks.
To provide the empirical evidence stemming from the case studies that grounds the results presented in this chapter.
To describe the case studies used for generating the emerging theory provided in this chapter.
The contribution we present in this chapter seeks to develop new theory useful for the oper- ations management academic community and for industrial practitioners. Our methodological choice for building new theory is basically inductive: our results are grounded (Glaser and Strauss 1967; Strauss and Corbin 1990; Glaser 1992) in conceptualization on the di¤erent case studies (Eisenhardt 1989) we have carried out in real industrial settings, the knowledge we have acquired through these di¤erent research projects and the contrast with existing literature. For validating the emerging theory we used a deductive approach, using empirical evidence also coming from our case studies, validation by managers we interacted with during our …eld work
and contrasting again with existing literature. Hence, the contribution of chapters 4 and 5 is conceptual and empirically supported by case studies.
The remainder of the chapter is organized as follows. In section 2, we justify the need for deepening in our knowledge on reusable articles, through an analysis of the academic literature related with the topic. In section 3, the emerging theory proposed in this chapter is presented: we sharpen our de…nition of RA and we present our typology for RA: three di¤erent types of RA are identi…ed and we make clear which are the similarities and di¤erences among them. In addition, two di¤erent types of reusable articles networks (depending on how the physical ‡ows in the system are organised) are introduced. Next, in section 4, we condense the empirical evidence (stemming from the case studies) that supports the statements put forward in chapters 4 and 5. Section 5 provide an structured detailed description of the case studies that were carried out throughout this thesis. Finally, in section 6 the conclusions of this chapter are presented.