As a result of rapid product development, the product life cycle has become shorter, and thus the amount of waste from discarded industrial products has risen dramatically. An awareness of the world???s environmental problems has stimulated researchers to explore the opportunities to reuse, recycle and remanufacture end-of-life products. Disassembly is a systematic approach to separating products into components or subassemblies in order to facilitate recovery of components or materials. However, the full disassembly of a product tends to be unproductive due to technical and cost constraints and product conditions after usage. Therefore, selective disassembly has been introduced as a more practical approach, where only a limited number of disassembly paths that lead to selected parts with recovering potential are considered. This research focuses on the development of a selective disassembly methodology by reversing an assembly sequencing approach. The methodology uses a step-by-step approach to generate a disassembly sequence diagram. This involves listing all the parts within the product, generating a liaison diagram to illustrate part relationships and then establishing precedence rules describing prerequisite actions for each liaison. This is followed by segregating disassembly paths that lead to the removal of selected parts or subassemblies. Then a winnowing process is applied to these paths to eliminate invalid disassembly states and transitions. The last step is to select the optimal disassembly path by using the time requirement as the main selection criterion. In order to shorten the time for carrying out the sequencing process, a javabased program that is capable of performing the first three steps has been created. The program requires three basic inputs in forms of precedence rules, and user-required part (s) and disassembly rules, prescribing which liaison (s) should be done subsequent to a particular liaison. The viability of the methodology and the program is proved through seven case studies conducted on a fishing reel, a single-hole punch, a kettle, an entire washing machine and three washing machine subassemblies. The application of the program allows the users to determine an optimal disassembly sequence in a very short time and with only basic product information as the input.

Zugl.: Regensburg, Universiẗat, Diss., 2007.

University of Macau / Faculty of Science and Technology / Department of Civil and Environmental Engineering

Despite the growing interest in heterogeneous polymerization catalysis, the majority of the polymerization catalysts used industrially are single-use entities that are left in the polymer product. Recoverable and recyclable polymerization catalysts have not reached the industrial utility of single-use catalysts because the catalyst and product separation have not become economical. The successful development of recyclable transition metal polymerization catalysts must take a rational design approach, hence academic and industrial researchers need to further expand the fundamental science and engineering of recyclable polymerization catalysis to gain an understanding of critical parameters that allow for the design of economically viable, recoverable solid polymerization catalysts. Unfortunately, the rapid development of Atom Transfer Radical Polymerization over the past 10 years has not resulted in its wide spread industrial practice. Numerous reports regarding the immobilization of transition metal ATRP catalysts, in attempts to increase its applicability, have extended the fundamentals of recyclable polymerization catalysis. However, for industrial viability, more research is required in the area of how the catalyst complex immobilization methodology and support structure affect the catalyst polymerization performance, regeneration, and recyclability. A comprehensive rational catalyst design approach of silica-immobilized ATRP catalyst was undertaken to answer these questions and are discussed here.

Composites are widely used in an increasing number of applications in diverse fields. However, most traditional composite materials are difficult to recycle. Because of their enhanced recyclability, thermoplastic single-polymer composites (SPCs), i.e., composites with fiber and matrix made from the same thermoplastic polymer, have attracted much attention in the recent years. High-performance polymer fibers in combination with same polymer matrices would lead to a fully recyclable single polymer composite that has major ecological advantages. However, because a single polymer is involved in the composite, thermoplastic SPCs manufacturing presents a unique set of technical problems, and different approaches from those in standard composites manufacturing are frequently needed. Two specific issues in SPCs manufacturing are how to produce distinct forms of the same polymer and how to consolidate them. So far, most investigations have been reported on a single-component hot compaction method and two-component molecular methods. However, in these methods, either the processing window is too narrow or some impure materials are introduced into the system. The key issue in thermoplastic SPCs processing is how to melt-process the matrix without significantly annealing or even melting the fiber. To overcome the above drawbacks in existing SPCs processing, particularly to widen the SPCs processing temperature window and to purify the SPCs, a novel SPCs manufacturing process utilizing the characteristics of slowly crystallizing polymers was developed and investigated. Highly oriented and highly crystalline fibers made of a slowly crystallizing polymer are mixed with the amorphous form of the same polymer and then consolidated together under heat and pressure. In this dissertation research, two slowly crystallizing polymers, poly(ethylene terephthalate) (PET) and poly(lactic acid) (PLA), were used as model systems for SPCs processing.. To study the deformation and failure mechanisms of PET and PLA SPCs, the SPCs were characterized using tensile test, tearing test, impact test, SEM, optical microscopy, and other methods. The change of crystallinity and orientation of the material forms during SPCs processing were characterized by DSC and XRD. The effects of major process conditions on the performance of the SPCs were studied. It was found that the processing temperature played a profound role in affecting the fiber-matrix bonding property. The compression molded SPCs exhibited enhanced mechanical properties. For the PET SPCs with 45% by weight fiber content the tensile strength is four folds of that of non-reinforced PET. After reinforcement, the tearing strength of the PLA SPCs is almost an order higher than that of the non-reinforced PLA. The fusion bonding behavior of two crystallizable amorphous PET sheets was also studied. Several characterization methods including SEM, TEM and polarized microscopy (either on etched or on non-etched samples) were used to observe interfacial bonding morphology of the crystallizable amorphous PET sheets. For a bonded sample, a layer of transcrystals with a thickness of 1-2 Ým was found right at the interface. A secondary but much larger zone with a distinct morphology was observed outside the transcrystal layer. With increase of the heating time, the width of the whole interfacial region decreases. The interfacial morphology was found to significantly affect the interfacial bonding quality. The testing results further indicated that high bonding temperature with an appropriate holding time promotes interfacial bonding of two crystallizable amorphous PET.

Electronic waste has become a growing concern in the world among governments, businesses, and consumers. These concerns are well founded as electronics waste presents economic, social, and environmental challenges. Economically, discarding electronic waste into landfills represents inefficient use of valuable materials and energy resources. Socially, improperly recycled electronic waste that takes place in third world countries with poor labor standards represents a moral dilemma for developed countries. Environmentally, electronic waste is a threat to all living organisms as it contains proportionally high levels of poisonous and toxic materials. To deal with these growing challenges a strong response needs to be made by all the stakeholders in the life-cycle of electronic devices. However, despite the apparent need, compared to the rapid increases in electronic technology that make it faster, more available, and more affordable, the technology to process electronic waste has not kept pace. This fact alone points to the inadequate funding, attention, and research that has been invested in the problem. Though it also points to an opportunity; the opportunity to build an efficient system to deal with the problem using what is already known about the lifecycle of electronic devices. Therefore, the goal of this work is to create a modeling tool to help stakeholders in the lifecycle of electronic devices understand the consequences of their choices as they affect the use of material and energy resources. To focus the research, LCD computer monitors are chosen as a case study. LCD computer monitors provide a level of sophistication high enough to be interesting in terms of the stakeholders involved, yet simple enough to provide a reasonable scope for this research that is still accessible to the layman As a corollary to this modeling effort, the relatively new systems modeling language SysML and ParaMagic, a program that integrates analysis modeling capability into SysML, will be evaluated. SysML was designed with Model Based Systems Engineering principles in mind thus it seems that it is a natural fit to the problem domain. Furthermore, testing SysML will provide insight into the advantages and disadvantages of the new language. The findings with respect to LCD computer monitors show that increasing the number of end of life options and the amount of monitors flowing into those options could result in substantial network wide material and energy savings. The findings with respect to SysML and ParaMagic are mixed. Although SysML provides tremendous modeling freedom, this freedom can result in increased upfront costs for developing executable models. Similarly, ParaMagic was found to be an effective tool for creating small executable models, but as the size of models increase its effectiveness tends to zero.

abstract / toc / Environmental Management / Master / Master of Science in Environmental Management

Landfills in British Columbia are reaching capacity; this has sparked renewed efforts to curb the output of household waste. Extending previous quantitative studies, I use a qualitative grounded theory approach to explore what influences the perception of waste and activates the intention to recycle and compost. Participants from Ucluelet, British Columbia, accumulated their refuse, recyclables, and compost during a four week period; simultaneously, I interviewed them about the meanings and feelings they associated with the process. My results suggest that participants' attitudes about waste are strongly influenced by what they see. Because garbage is regularly hauled away and dumped out of sight, participants were relatively unaware of how much they produce and its environmental impact. Increasing awareness appears to be a key factor in changing waste diversion intentions; incorporating small pro-environmental changes may lead to further changes. This reaffirms previous findings that adopting one environmental behaviour can empower further change.

Thesis (M.Tech.: Marketing)-Dept. of Marketing, Durban University of Technology, 2006 xii, 152 leaves / Consumer attitudes play an important role when it comes to waste management. Consumers, who purchase any number of packaged goods also dispose of or discard waste in large quantities. In the business sector the introduction of new technologies in the production cycle is imperative, and this technology involves discovering more cost effective methods of reducing and reusing solid waste as a resource. The challenge for the eThekwini Municipality is to discover ways to reduce the volume of waste disposed at the landfills. This study determines the attitudes of consumers towards curbside recycling specifically within the eThekwini municipal region. This study focuses on various theories and evaluates ways in which waste prevention and reduction initiatives can be employed to protect the depletion of natural resources.

As a result of rapid product development, the product life cycle has become shorter, and thus the amount of waste from discarded industrial products has risen dramatically. An awareness of the world???s environmental problems has stimulated researchers to explore the opportunities to reuse, recycle and remanufacture end-of-life products. Disassembly is a systematic approach to separating products into components or subassemblies in order to facilitate recovery of components or materials. However, the full disassembly of a product tends to be unproductive due to technical and cost constraints and product conditions after usage. Therefore, selective disassembly has been introduced as a more practical approach, where only a limited number of disassembly paths that lead to selected parts with recovering potential are considered. This research focuses on the development of a selective disassembly methodology by reversing an assembly sequencing approach. The methodology uses a step-by-step approach to generate a disassembly sequence diagram. This involves listing all the parts within the product, generating a liaison diagram to illustrate part relationships and then establishing precedence rules describing prerequisite actions for each liaison. This is followed by segregating disassembly paths that lead to the removal of selected parts or subassemblies. Then a winnowing process is applied to these paths to eliminate invalid disassembly states and transitions. The last step is to select the optimal disassembly path by using the time requirement as the main selection criterion. In order to shorten the time for carrying out the sequencing process, a javabased program that is capable of performing the first three steps has been created. The program requires three basic inputs in forms of precedence rules, and user-required part (s) and disassembly rules, prescribing which liaison (s) should be done subsequent to a particular liaison. The viability of the methodology and the program is proved through seven case studies conducted on a fishing reel, a single-hole punch, a kettle, an entire washing machine and three washing machine subassemblies. The application of the program allows the users to determine an optimal disassembly sequence in a very short time and with only basic product information as the input.