Thesis (doctoral)--Technische Universiteit Delft, 1997. / Includes bibliographical references (p. [159]-163).

Thesis (Ph. D.)--Florida State University, 2004. / Advisor: Dr. Ching-Jen Chen, Florida State University, College of Engineering, Dept. of Mechanical Engineering. Title and description from dissertation home page (viewed Sept. 22, 2004). Includes bibliographical references.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 80-83). Also available on the Internet.

Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Tummala, Rao; Committee Member: Pucha, Raghuram V.; Committee Member: Wong, C.P. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 80-83). Also available on the Internet.

M.Tech. (Mechanical Engineering) / This dissertation focuses on understanding the relation between aerodynamic drag and aerodynamic lift in modern passenger cars and explores what effect these forces have on a vehicle. Modern cars are capable of exceptionally high speed and are subjected to large destabilizing lift forces at these speeds. To counteract the effects of positive lift, various aerodynamic devices and body design details are included in the typical car design. These devices often increase the vehicles aerodynamic drag, reducing energy efficiency as speed increases. The problem that this project aims to address is that at typical commuting speeds where lift forces are low these counter lift devices are not required, however because these devices are fixed the losses associated with their increased drag is still incurred. The devices can however not be excluded from the design as they are required on occasions that the vehicle is driven at abnormally high speed and lift forces become large. The losses associated with the increased drag of such devices are incurred over the vehicles full range of speeds even though the devices are only required at higher speed. The objective of this project is to develop an aerodynamic system that allows the vehicle to continuously and autonomously adjust its drag vs. lift properties to an optimal compromise that suits the vehicles instantaneous aerodynamic requirements. The system offers improvements in both handling and breaking performance as well as increased energy efficiency. The feasibility and effectiveness of the developed system is compared against the performance of a standard test vehicle and against the same test vehicle equipped with various traditional fixed aerodynamic devices. The methods used to develop, analyse and compare the various test models include both practical testing of a physical vehicle and computer based simulation using a digitized model of the same vehicle. Practical testing was conducted at Gerotek test facilities in Pretoria, South Africa and includes measuring the flow rate through the engine cooling system to determine the drag contribution of the cooling system to total vehicle drag. Coast-down testing is used to characterise the test vehicles rolling resistance and skid-pan or circuit tests are used to characterise the vehicles handling properties. Acceleration and breaking tests are also performed. Data from these tests are recorded through various on-board data logging units with pitot tube, GPS and accelerometer devices as inputs. A 3D model of the test vehicle is compiled using photogrammetry software to capture the profile and dimensions of the test vehicle into digital form. A 3D CAD model is developed from the vehicle scan and is used for CFD simulations to solve for the vehicles aerodynamic properties and to assist in the design and incorporation of the various adjustable aerodynamic devices required for the project. The data accumulated through computer simulation and practical testing is combined to form a statistical computer model of the standard vehicle. Research is conducted on existing aerodynamic devices common to passenger cars and suitable devices are adapted to three additional computer models: One with an adaptive aerodynamic system and two with fixed aerodynamic configurations of different intensities. The performance and energy efficiency of the four models are analytically simulated and the results are compared directly. The study shows that in terms of sporting performance around a theoretical road circuit, the adaptive model outperforms both the standard vehicle and fixed configuration models by a small degree, +-2.3%. The standard vehicle is found to have a lift coefficient CL=0.43 with a drag coefficient of Cd=0.31. The dynamic model is able to realize combinations of low drag or low lift between the limits of Cd=0.3, CL=0.34 and Cd=0.32, CL=0.03. The variable aerodynamic properties allow for a 5.5% increase in maximum cornering speed and a 20% improvement in acceleration time from standstill to terminal speed. The percentage improved lap time would be greater if the effects of breaking from the higher terminal speed achieved by the dynamic model were ignored for the simulation...

Reconhecido como um problema mundial, o crescente volume de resíduos eletrônicos tem representado uma preocupação quanto às práticas de descarte destes equipamentos por utilizar na fabricação produtos e metais tóxicos com possíveis danos à saúde dos seres humanos e ao ambiente. Os resíduos de equipamentos eletroeletrônicos também possuem em sua composição metais preciosos como ouro e a prata, além de teores significativos de cobre, representando fonte de interesse comercial na recuperação destes materiais, reduzindo a necessidade de exploração destes recursos na natureza. Estes fatores associados à rápida obsolescência e posterior descarte impulsionou uma complexa cadeia produtiva formada por empresas que coletam, separam, fracionam, recuperam, armazenam e reciclam estes materiais. Neste fluxo ocorrem várias interações entre as empresas e a sociedade com consequentes impactos sociais, econômicos e ambientais. Esta pesquisa realizou um diagnóstico de uma parte desta cadeia, compreendida pelos “processadores de resíduos”, entendido como as empresas que realizam a coleta, armazenagem, segregação e descaracterização dos equipamentos. Seus processos são em sua maioria manuais e, em alguns casos, algumas etapas de processamento mecânico. Operam na etapa de pré-processamento como fornecedores de insumos para o restante da cadeia. Estas empresas não realizam os procedimentos mais complexos da reciclagem, como a pirometalurgia, hidrometalurgia e eletrometalurgia. Para atingir o objetivo proposto foi utilizado um questionário semiestruturado direcionado a empresas previamente selecionadas e de abrangência nacional. Os dados coletados foram tabulados e analisados em seus contextos qualitativos e quantitativos, com o cruzamento de informações. Os resultados da pesquisa forneceram um conjunto de informações a respeito do sistema produtivo, dos volumes processados e de aspectos econômicos e de gestão do setor. Foi possível identificar os vários níveis de amadurecimento e gestão, onde algumas empresas operam com consistente estrutura administrativa, conhecimento, cumprimento da legislação e consciência ambiental, e outras, com sistemas de gestão deficientes e quase informalidade. Possuem capacidade média de processamento de resíduos de 100 toneladas/mês, e utilização de 50% desta capacidade. A parcela reciclável dos resíduos é em média 80% do total do material coletado. Os setores da sociedade que mais contribuem com resíduos são a indústria com 41,25% seguido do comércio e doméstico. No contexto econômico, 70% do faturamento tem origem no processamento de placas de circuito integrado. Quanto à comercialização dos produtos 75,39% tem como destino outros recicladores no Brasil ou exterior. Os dados coletados sobre os custos de processamento não foram satisfatórios pelo reduzido número de respostas, demonstrando que a questão poderia ter sido mais bem formulada ou a técnica de coleta melhor estudada. As principais contribuições resultantes deste trabalho são fornecer uma visão do fluxo e do volume de resíduos processados, possibilitar uma compreensão das interações econômicas entre os diversos interessados e das dificuldades que o setor enfrenta para alcançar um sistema de gestão sustentável para os resíduos eletroeletrônicos. / Recognized as a world problem, the increasing volume of electronic waste gives rise to as much concern as the practice of discarding this equipment because, in its fabrication, toxic metals are used, which causes possible health risks for human beings and for the environment. Electronic equipment waste also has precious metals within its composition, such as gold and silver, besides significant levels of copper, which represents a source of commercial interest in terms of the recuperation of these materials and a subsequent reduction in the necessity of exploration of these natural resources. These factors, together with the rapid transformation into obsolescence and later disposal of the equipment, has stimulated a complex production chain made up of companies who collect, separate, break up, recuperate, store and recycle these materials. In this interchange, various interactions occur between the companies and the society with a consequent social, economic and environmental impact. The present research has made a diagnosis of one part of this chain, as in the “waste processors”, that means the companies which carry out the collection, storage, separation and transformation of the equipment. The majority of the processes are manual with a few cases of mechanical processes in some stages. They operate at the pre-processing stage as input suppliers for the rest of the chain. These companies do not carry out the more complex procedures of recycling, such as pyrometallurgy, hydrometallurgy or electrometallurgy. To achieve the proposed objective, a semi-structured questionnaire was used, directed towards previously selected companies on a national scale. The collected data were tabled and analyzed within their qualitative and quantitative context with a cross-check information. The results of the research produced information in relation to the productive system, the volume which is processed, the economic aspects and the sector management. It was possible to identify the various levels of maturation and management, where some companies operate with a consistent administrative structure, knowledge, compliance with the law and environmental consciousness but where others operate with deficient management and a lack of formality. They have an average capacity of waste processing of residues of 100 tons per month with 50% utilization of this capacity. The recycled part of the waste represents an average of 80% of the total amount of collected material. The sectors that more generate this kind of waste are the industrial sector, with 41.25%, followed by the commercial and domestic sectors. Within an economic context, 70% of the income originates from Printed Circuit Boards (PCBs). Regarding the commercialization of the products, 75.39% are destined for other recycling plants in both Brazil and abroad. The collected data were not satisfactory in relation to the processing costs because of the low number of replies, demonstrating that the questions in relation to this could have been better formulated or the information collecting method should be improved. The main contributions resulting from this study are: create a vision of the volume flux of processed waste and allow for comprehension of the economical interactions between the various interested parties and the difficulties which the sector faces to achieve a sustainable management system for electronic waste.

Reconhecido como um problema mundial, o crescente volume de resíduos eletrônicos tem representado uma preocupação quanto às práticas de descarte destes equipamentos por utilizar na fabricação produtos e metais tóxicos com possíveis danos à saúde dos seres humanos e ao ambiente. Os resíduos de equipamentos eletroeletrônicos também possuem em sua composição metais preciosos como ouro e a prata, além de teores significativos de cobre, representando fonte de interesse comercial na recuperação destes materiais, reduzindo a necessidade de exploração destes recursos na natureza. Estes fatores associados à rápida obsolescência e posterior descarte impulsionou uma complexa cadeia produtiva formada por empresas que coletam, separam, fracionam, recuperam, armazenam e reciclam estes materiais. Neste fluxo ocorrem várias interações entre as empresas e a sociedade com consequentes impactos sociais, econômicos e ambientais. Esta pesquisa realizou um diagnóstico de uma parte desta cadeia, compreendida pelos “processadores de resíduos”, entendido como as empresas que realizam a coleta, armazenagem, segregação e descaracterização dos equipamentos. Seus processos são em sua maioria manuais e, em alguns casos, algumas etapas de processamento mecânico. Operam na etapa de pré-processamento como fornecedores de insumos para o restante da cadeia. Estas empresas não realizam os procedimentos mais complexos da reciclagem, como a pirometalurgia, hidrometalurgia e eletrometalurgia. Para atingir o objetivo proposto foi utilizado um questionário semiestruturado direcionado a empresas previamente selecionadas e de abrangência nacional. Os dados coletados foram tabulados e analisados em seus contextos qualitativos e quantitativos, com o cruzamento de informações. Os resultados da pesquisa forneceram um conjunto de informações a respeito do sistema produtivo, dos volumes processados e de aspectos econômicos e de gestão do setor. Foi possível identificar os vários níveis de amadurecimento e gestão, onde algumas empresas operam com consistente estrutura administrativa, conhecimento, cumprimento da legislação e consciência ambiental, e outras, com sistemas de gestão deficientes e quase informalidade. Possuem capacidade média de processamento de resíduos de 100 toneladas/mês, e utilização de 50% desta capacidade. A parcela reciclável dos resíduos é em média 80% do total do material coletado. Os setores da sociedade que mais contribuem com resíduos são a indústria com 41,25% seguido do comércio e doméstico. No contexto econômico, 70% do faturamento tem origem no processamento de placas de circuito integrado. Quanto à comercialização dos produtos 75,39% tem como destino outros recicladores no Brasil ou exterior. Os dados coletados sobre os custos de processamento não foram satisfatórios pelo reduzido número de respostas, demonstrando que a questão poderia ter sido mais bem formulada ou a técnica de coleta melhor estudada. As principais contribuições resultantes deste trabalho são fornecer uma visão do fluxo e do volume de resíduos processados, possibilitar uma compreensão das interações econômicas entre os diversos interessados e das dificuldades que o setor enfrenta para alcançar um sistema de gestão sustentável para os resíduos eletroeletrônicos. / Recognized as a world problem, the increasing volume of electronic waste gives rise to as much concern as the practice of discarding this equipment because, in its fabrication, toxic metals are used, which causes possible health risks for human beings and for the environment. Electronic equipment waste also has precious metals within its composition, such as gold and silver, besides significant levels of copper, which represents a source of commercial interest in terms of the recuperation of these materials and a subsequent reduction in the necessity of exploration of these natural resources. These factors, together with the rapid transformation into obsolescence and later disposal of the equipment, has stimulated a complex production chain made up of companies who collect, separate, break up, recuperate, store and recycle these materials. In this interchange, various interactions occur between the companies and the society with a consequent social, economic and environmental impact. The present research has made a diagnosis of one part of this chain, as in the “waste processors”, that means the companies which carry out the collection, storage, separation and transformation of the equipment. The majority of the processes are manual with a few cases of mechanical processes in some stages. They operate at the pre-processing stage as input suppliers for the rest of the chain. These companies do not carry out the more complex procedures of recycling, such as pyrometallurgy, hydrometallurgy or electrometallurgy. To achieve the proposed objective, a semi-structured questionnaire was used, directed towards previously selected companies on a national scale. The collected data were tabled and analyzed within their qualitative and quantitative context with a cross-check information. The results of the research produced information in relation to the productive system, the volume which is processed, the economic aspects and the sector management. It was possible to identify the various levels of maturation and management, where some companies operate with a consistent administrative structure, knowledge, compliance with the law and environmental consciousness but where others operate with deficient management and a lack of formality. They have an average capacity of waste processing of residues of 100 tons per month with 50% utilization of this capacity. The recycled part of the waste represents an average of 80% of the total amount of collected material. The sectors that more generate this kind of waste are the industrial sector, with 41.25%, followed by the commercial and domestic sectors. Within an economic context, 70% of the income originates from Printed Circuit Boards (PCBs). Regarding the commercialization of the products, 75.39% are destined for other recycling plants in both Brazil and abroad. The collected data were not satisfactory in relation to the processing costs because of the low number of replies, demonstrating that the questions in relation to this could have been better formulated or the information collecting method should be improved. The main contributions resulting from this study are: create a vision of the volume flux of processed waste and allow for comprehension of the economical interactions between the various interested parties and the difficulties which the sector faces to achieve a sustainable management system for electronic waste.

Reconhecido como um problema mundial, o crescente volume de resíduos eletrônicos tem representado uma preocupação quanto às práticas de descarte destes equipamentos por utilizar na fabricação produtos e metais tóxicos com possíveis danos à saúde dos seres humanos e ao ambiente. Os resíduos de equipamentos eletroeletrônicos também possuem em sua composição metais preciosos como ouro e a prata, além de teores significativos de cobre, representando fonte de interesse comercial na recuperação destes materiais, reduzindo a necessidade de exploração destes recursos na natureza. Estes fatores associados à rápida obsolescência e posterior descarte impulsionou uma complexa cadeia produtiva formada por empresas que coletam, separam, fracionam, recuperam, armazenam e reciclam estes materiais. Neste fluxo ocorrem várias interações entre as empresas e a sociedade com consequentes impactos sociais, econômicos e ambientais. Esta pesquisa realizou um diagnóstico de uma parte desta cadeia, compreendida pelos “processadores de resíduos”, entendido como as empresas que realizam a coleta, armazenagem, segregação e descaracterização dos equipamentos. Seus processos são em sua maioria manuais e, em alguns casos, algumas etapas de processamento mecânico. Operam na etapa de pré-processamento como fornecedores de insumos para o restante da cadeia. Estas empresas não realizam os procedimentos mais complexos da reciclagem, como a pirometalurgia, hidrometalurgia e eletrometalurgia. Para atingir o objetivo proposto foi utilizado um questionário semiestruturado direcionado a empresas previamente selecionadas e de abrangência nacional. Os dados coletados foram tabulados e analisados em seus contextos qualitativos e quantitativos, com o cruzamento de informações. Os resultados da pesquisa forneceram um conjunto de informações a respeito do sistema produtivo, dos volumes processados e de aspectos econômicos e de gestão do setor. Foi possível identificar os vários níveis de amadurecimento e gestão, onde algumas empresas operam com consistente estrutura administrativa, conhecimento, cumprimento da legislação e consciência ambiental, e outras, com sistemas de gestão deficientes e quase informalidade. Possuem capacidade média de processamento de resíduos de 100 toneladas/mês, e utilização de 50% desta capacidade. A parcela reciclável dos resíduos é em média 80% do total do material coletado. Os setores da sociedade que mais contribuem com resíduos são a indústria com 41,25% seguido do comércio e doméstico. No contexto econômico, 70% do faturamento tem origem no processamento de placas de circuito integrado. Quanto à comercialização dos produtos 75,39% tem como destino outros recicladores no Brasil ou exterior. Os dados coletados sobre os custos de processamento não foram satisfatórios pelo reduzido número de respostas, demonstrando que a questão poderia ter sido mais bem formulada ou a técnica de coleta melhor estudada. As principais contribuições resultantes deste trabalho são fornecer uma visão do fluxo e do volume de resíduos processados, possibilitar uma compreensão das interações econômicas entre os diversos interessados e das dificuldades que o setor enfrenta para alcançar um sistema de gestão sustentável para os resíduos eletroeletrônicos. / Recognized as a world problem, the increasing volume of electronic waste gives rise to as much concern as the practice of discarding this equipment because, in its fabrication, toxic metals are used, which causes possible health risks for human beings and for the environment. Electronic equipment waste also has precious metals within its composition, such as gold and silver, besides significant levels of copper, which represents a source of commercial interest in terms of the recuperation of these materials and a subsequent reduction in the necessity of exploration of these natural resources. These factors, together with the rapid transformation into obsolescence and later disposal of the equipment, has stimulated a complex production chain made up of companies who collect, separate, break up, recuperate, store and recycle these materials. In this interchange, various interactions occur between the companies and the society with a consequent social, economic and environmental impact. The present research has made a diagnosis of one part of this chain, as in the “waste processors”, that means the companies which carry out the collection, storage, separation and transformation of the equipment. The majority of the processes are manual with a few cases of mechanical processes in some stages. They operate at the pre-processing stage as input suppliers for the rest of the chain. These companies do not carry out the more complex procedures of recycling, such as pyrometallurgy, hydrometallurgy or electrometallurgy. To achieve the proposed objective, a semi-structured questionnaire was used, directed towards previously selected companies on a national scale. The collected data were tabled and analyzed within their qualitative and quantitative context with a cross-check information. The results of the research produced information in relation to the productive system, the volume which is processed, the economic aspects and the sector management. It was possible to identify the various levels of maturation and management, where some companies operate with a consistent administrative structure, knowledge, compliance with the law and environmental consciousness but where others operate with deficient management and a lack of formality. They have an average capacity of waste processing of residues of 100 tons per month with 50% utilization of this capacity. The recycled part of the waste represents an average of 80% of the total amount of collected material. The sectors that more generate this kind of waste are the industrial sector, with 41.25%, followed by the commercial and domestic sectors. Within an economic context, 70% of the income originates from Printed Circuit Boards (PCBs). Regarding the commercialization of the products, 75.39% are destined for other recycling plants in both Brazil and abroad. The collected data were not satisfactory in relation to the processing costs because of the low number of replies, demonstrating that the questions in relation to this could have been better formulated or the information collecting method should be improved. The main contributions resulting from this study are: create a vision of the volume flux of processed waste and allow for comprehension of the economical interactions between the various interested parties and the difficulties which the sector faces to achieve a sustainable management system for electronic waste.

Thesis submitted in compliance with the requirements for the Master's Degree in Technology: Electrical Engineering - Light Current, Durban University of Technology, Department of Electronic Engineering, 2008. / Linear control systems can be easily tuned using classical tuning techniques such as the Ziegler-Nichols and Cohen-Coon tuning formulae. Empirical studies have found that these conventional tuning methods result in an unsatisfactory control performance when they are used for processes experiencing the negative destabilizing effects of strong nonlinearities. It is for this reason that control practitioners often prefer to tune most nonlinear systems using trial and error tuning, or intuitive tuning. A need therefore exists for the development of a suitable tuning technique that is applicable for a wide range of control loops that do not respond satisfactorily to conventional tuning. Emerging technologies such as Swarm Intelligence (SI) have been utilized to solve many non-linear engineering problems. Particle Swarm Optimization (PSO), developed by Eberhart and Kennedy (1995), is a sub-field of SI and was inspired by swarming patterns occurring in nature such as flocking birds. It was observed that each individual exchanges previous experience, hence knowledge of the “best position” attained by an individual becomes globally known. In the study, the problem of identifying the PID controller parameters is considered as an optimization problem. An attempt has been made to determine the PID parameters employing the PSO technique. A wide range of typical process models commonly encountered in industry is used to assess the efficacy of the PSO methodology. Comparisons are made between the PSO technique and other conventional methods using simulations and real-time control. / National Research Foundation