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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.
11

Reciclagem de isolantes térmicos presentes em defletores de calor automotivo

Moretti, João Paulo [UNESP] 18 December 2012 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:29:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-12-18Bitstream added on 2014-06-13T18:39:08Z : No. of bitstreams: 1 moretti_jp_me_bauru.pdf: 623430 bytes, checksum: 8a8b037467da86497bd4f13030b6c3d1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os defletores de calor automotivos são constituídos de uma carcaça de aço aluminizado que envolve um isolante térmico, fisicamente bastante semelhante ao papel, entrentanto com uma composição elevada de partes inorgânicas, chegando a cerca de 80% do material seco. Esses materiais são utilizados para a proteção de vários componentes fundamentais nos veículos presentes em locais de temperaturas extremamentes elevadas, tais como o bloco do motor e o sistema de exaustão de gases. Essa proteção garantes a integridade de peças vitais sensíveis ao calor, como por exemplo, os circuitos eletro-eletrônicos. Neste trabalho, recortes do elemento defletor de calor foram reciclados em sistema manual e em escala industrial e propriedades como espessura, densidade, compreensibilidade, retorno, teor de cinzas, efetividade da deflexão de calor, além da análise por termogravimetria e microscopia eletrônica de varredura com acoplamento de sistema de energia dispersiva (EDS) foram realizados. Os produtos reciclados demonstraram resultados positivos quanto aos ensaios de deflexão de calor, teor de cinzas, ensaio termogravimétrica e visualmente dos espectros de energia dispersiva, indicando a manutenção da composição geral do material após os processos de reciclagem realizados. Os resultados dos ensaios físicos, como espessura, densidade, resistência à tração após quatro horas a sem graus Celsius, resistência à tração após 22 horas a 200 graus Celsius, compreessibilidade e retorno, compressibilidade e retorno após 22 horas a 200 graus Celsius, apontaram variações de acordo com a prensagem exercida no material, indicando a necessidade de melhorias nos processos de reciclagem utilizados / The automotive heat shields are made of an aluminized steel housing that surrounds a thermal insulator, physically quite similar to paper, though with a composition of inorganic parts high, reaching about 80% of dry material. These materials are used to protect several key components in vehicles sites present in extremely high temperatures, such as the engine block and the exhaust gas system. This protetion ensures the integrity of vital parts sensitive to heat, such as electric and electronic circuits. In this paper, clippings element baffe heat were recycled in manual in industrial scale and properties such as thickness, density, compressibility, recovery, ignition loss, effectiveness of heat deflection, and thermogravimetric analysis and scanning electron microscopy with coupling energy dispersive system (EDS) were performed. The recycled product showed positive results regarding heat deflection tests, ash content, thermogravimetric test and visually energy dispersive spectra, indicating maintaining the overall composition of the material after recycling processes performed. The results of the physical tests such as thickness, density, tensile strengh after four hours at one hundred degrees Celsius tensile strength after twenty-two hours to two hundred degrees Celsius, and recovery, compressibility, compressibility and recovery after twenty-two hours to two hundred degrees Celsius, showed variations according to the press exerted on the material, pointing to the need for improvements in recycling processes used
12

Reciclagem de isolantes térmicos presentes em defletores de calor automotivo /

Moretti, João Paulo. January 2012 (has links)
Orientador: Sandro Donnini Mancini / Banca: Jane Maria Faulstich de Paiva / Banca: Maria Lucia Pereira Antunes / Resumo: Os defletores de calor automotivos são constituídos de uma carcaça de aço aluminizado que envolve um isolante térmico, fisicamente bastante semelhante ao papel, entrentanto com uma composição elevada de partes inorgânicas, chegando a cerca de 80% do material seco. Esses materiais são utilizados para a proteção de vários componentes fundamentais nos veículos presentes em locais de temperaturas extremamentes elevadas, tais como o bloco do motor e o sistema de exaustão de gases. Essa proteção garantes a integridade de peças vitais sensíveis ao calor, como por exemplo, os circuitos eletro-eletrônicos. Neste trabalho, recortes do elemento defletor de calor foram reciclados em sistema manual e em escala industrial e propriedades como espessura, densidade, compreensibilidade, retorno, teor de cinzas, efetividade da deflexão de calor, além da análise por termogravimetria e microscopia eletrônica de varredura com acoplamento de sistema de energia dispersiva (EDS) foram realizados. Os produtos reciclados demonstraram resultados positivos quanto aos ensaios de deflexão de calor, teor de cinzas, ensaio termogravimétrica e visualmente dos espectros de energia dispersiva, indicando a manutenção da composição geral do material após os processos de reciclagem realizados. Os resultados dos ensaios físicos, como espessura, densidade, resistência à tração após quatro horas a sem graus Celsius, resistência à tração após 22 horas a 200 graus Celsius, compreessibilidade e retorno, compressibilidade e retorno após 22 horas a 200 graus Celsius, apontaram variações de acordo com a prensagem exercida no material, indicando a necessidade de melhorias nos processos de reciclagem utilizados / Abstract: The automotive heat shields are made of an aluminized steel housing that surrounds a thermal insulator, physically quite similar to paper, though with a composition of inorganic parts high, reaching about 80% of dry material. These materials are used to protect several key components in vehicles sites present in extremely high temperatures, such as the engine block and the exhaust gas system. This protetion ensures the integrity of vital parts sensitive to heat, such as electric and electronic circuits. In this paper, clippings element baffe heat were recycled in manual in industrial scale and properties such as thickness, density, compressibility, recovery, ignition loss, effectiveness of heat deflection, and thermogravimetric analysis and scanning electron microscopy with coupling energy dispersive system (EDS) were performed. The recycled product showed positive results regarding heat deflection tests, ash content, thermogravimetric test and visually energy dispersive spectra, indicating maintaining the overall composition of the material after recycling processes performed. The results of the physical tests such as thickness, density, tensile strengh after four hours at one hundred degrees Celsius tensile strength after twenty-two hours to two hundred degrees Celsius, and recovery, compressibility, compressibility and recovery after twenty-two hours to two hundred degrees Celsius, showed variations according to the press exerted on the material, pointing to the need for improvements in recycling processes used / Mestre
13

Estudos de nanocompositos de poli(tereftalato de butileno) reciclado e argila montmorilonita organicamente modificada / Studies of recycled poly(butylene terephthalate) organically modified montmorillonite clay nanocomposites

Pampa Quispe, Noe Benjamin 12 August 2018 (has links)
Orientador: Julio Roberto Bartoli / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-12T05:46:37Z (GMT). No. of bitstreams: 1 PampaQuispe_NoeBenjamin_D.pdf: 4048674 bytes, checksum: 584228b9ad826cb07274497b4df107b0 (MD5) Previous issue date: 2007 / Resumo: Nanocompósitos poliméricos são novos materiais de grande interesse devido à sua favorável relação custo/benefício com a incorporação de pequenas quantidades de carga mineral, aumentado sua resistência térmica, retardante de chama e propriedades mecânicas dos polímeros. O processamento por fusão tem sido empregado com sucesso na preparação de nanocompósitos de polímero e argila usando diversos termoplásticos (commodities e de especialidade). Neste trabalho, poli[tereftalato de butileno], PBT, de reciclagem primária foi reforçado com argilas do tipo montmorilonita organicamente modificadas (MMT). O processo de preparação a partir do fundido, em extrusora de rosca dupla, foi empregado para obter compostos de PBT reciclado e MMT, em função da velocidade de rotação e tipo de nanoargila. Análises morfológicas de Difração de Raios-X (DRX) e Microscopia Eletrônica de Transmissão (MET) sugerem uma esfoliação parcial ou inicial da argila na matriz de PBT reciclado quando se usa a Cloisite 25A, menos organofílico, mas uma intercalação usando a Cloisite 20A. Análises de DMTA (modo de flexão), TGA e reológicas também foram sensíveis em mostrar diferenças entre os tipos de MMT e o efeito da rotação da rosca da extrusora ou taxa de cisalhamento usadas. Corpos de prova moldados por injeção foram preparados para caracterização mecânica. Foi verificada uma melhoria no módulo de elasticidade sob tração dos nanocompósitos de PBT reciclado quando comparado ao composto virgem e ao reciclado sem cargas, em especial usando a argila organicamente modificada Cloisite 25A. / Abstract: Polymeric nanocomposites are novel materials of huge interest due to their favorable cost/performance ratio with low amount of nanofillers, increasing thermal resistance, flame retardancy and mechanical properties of polymers. Polymer clay nanocomposite systems were successfully prepared by melt compounding using several thermoplastics (commodities and specialties). In this work, primary recycled poly(butylenes terephtalate), PBT, is being used to be reinforced with organic modified montmorillonite clays (MMT). Melt compounding with a twin-screw extruder was used to prepare recycled PBT/MMT compounds as a function of screw speed and grade of nanoclay. Morphological analysis X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) suggested that a partial or initial exfoliation of the nanoclay in the PBT compounds was achieved when using the grade Cloisite 25A, less organophylic, but an intercalation when using Cloisite 20A. DMTA (flexural mode), TGA and rheological characterizations were also sensitive to show differences between organoclay grades and the effect of screw speed or shear rate used. Injection molded specimens were prepared for mechanical characterization. It was found that tensile modulus of the recycled PBT nanocomposites was improved when compared to the virgin and recycled net PBT, specially using the organoclay grade Cloisite 25A. / Doutorado / Ciencia e Tecnologia de Materiais / Doutor em Engenharia Química
14

Inserção brasileira na cadeia global de reciclagem de Resíduos de Equipamentos Eletroeletrônicos (REEE) / Brazilian participation in the recycling global chain of Waste Electrical and Electronic Equipment (WEEE)

Mazon, Marília Tunes, 1988- 25 August 2018 (has links)
Orientadores: Newton Muller Pereira, Marco Antonio Silveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-25T03:21:26Z (GMT). No. of bitstreams: 1 Mazon_MariliaTunes_M.pdf: 1700744 bytes, checksum: 07023c5f77405c9bddea2ce971724373 (MD5) Previous issue date: 2014 / Resumo: Os Resíduos de Equipamentos Eletroeletrônicos (REEE), apesar de conterem substâncias perigosas ao meio ambiente e à saúde humana, tais como chumbo, cádmio e mercúrio, também contêm metais nobres, como ouro, prata e platina, característica que confere a estes resíduos alto valor agregado, se reciclados. A rápida expansão do mercado de eletroeletrônicos, o aumento dos fluxos legais e ilegais de REEE e a emergência em nível internacional de regulações específicas justificam a necessidade de estudos a este respeito. Esta dissertação debate o tema a partir de duas perspectivas que se sobrepõem: os REEE como commodities (1) e os REEE inseridos em uma lógica de cadeia global (2). Entende-se que a dicotomia "lixo" e "valor" corresponde neste caso às diferenças econômicas e tecnológicas que dão forma às frentes de inserção na cadeia global de reciclagem de REEE. No setor formal, enquanto as etapas de pré-processamento estão localizadas em países em desenvolvimento, as etapas de processamento final (de maior intensidade tecnológica por envolver a recuperação de metais nobres) estão localizadas em países desenvolvidos. A partir dessa problemática, o objetivo desta dissertação é o de descrever a cadeia de reciclagem de REEE no Brasil e analisar sua inserção global. Dado que, no país, o setor conta com recicladoras nacionais voltadas à fase de separação e desmantelamento e com recicladoras multinacionais estrangeiras (EMNs), voltadas à exportação de placas de circuito impresso para suas matrizes, o presente estudo avalia as perspectivas e barreiras para o desenvolvimento deste mercado nas dimensões política, regulatória, tecnológica e de valor, e reflete sobre o papel das EMNs para o seu desenvolvimento. Para tal, o estudo contou com o levantamento e a revisão bibliográfica da literatura nacional e internacional, de relatórios de instituições governamentais e privadas e de regulações sobre o tema, além de uma pesquisa de campo com recicladoras nacionais e estrangeiras instaladas em território brasileiro. Constatou-se que, apesar de algumas recicladoras no Brasil possuírem processos semiautomáticos de separação e desmantelamento, o país ainda enfrenta limites para o tratamento de metais nobres e outros materiais complexos. No que diz respeito às vias de catching-up tecnológico, conclui-se que estas se mostram mais prováveis por meio da intervenção estatal e do fortalecimento da regulação vigente do que pela presença de EMNs / Abstract: Waste Electrical and Electronic Equipment (WEEE), while containing hazardous substances to the environment and human health, such as lead, cadmium and mercury, also contain noble metals such as gold, silver and platinum, a characteristic that gives to these waste high value-added, if recycled. The rapid expansion of the electronics market, the increase in legal and illegal flows of WEEE and the emergence of specific regulations worldwide justify the need for studies in this regard. This dissertation discusses the issue from two perspectives that overlap: WEEE as commodities (1) and WEEE as into a global chain logic (2). It is understood that the dichotomy "waste" and "value" in this case corresponds to the economic and technological differences that shape the forms of insertion in the recycling global chain of WEEE. In the formal sector, while the pre-processing steps are located in developing countries, the final processing steps (involving higher technology by engaging the recovery of noble metals) are located in developed countries. From this problematic, the aim of this dissertation is to describe the WEEE recycling chain in Brazil and to analyse its global insertion. Since, in the country, the national recycling industries are focused on separation and dismantling processes and foreign recycling multinationals (MNCs) are export-oriented on printed circuit boards, this study assesses the prospects and barriers for this market development in political, regulatory, technological and value dimensions, and reflects on the role of MNCs for their development. By these means, the study included the survey and literature review of national and international literature, reports of governmental and private institutions and regulations on the subject, besides a field research with domestic and foreign recyclers installed in Brazilian territory. It was concluded that, despite some recyclers possesses semiautomatic separation and dismantling processes, the country still faces limits for the treatment of noble metals and other complex materials. With regard to the means of technological catching-up, it concluded that these are most likely through state intervention and strengthening of the existing regulation than by the presence of MNCs / Mestrado / Politica Cientifica e Tecnologica / Mestra em Política Científica e Tecnológica
15

The role played by subsistence waste pickers in recycling

Mamphitha, David 15 July 2012 (has links)
South Africa has one of the highest unemployment rates in the world. The majority of the economically active, but unemployed people enter the informal economic sector, as a means to make ends meet. Waste recycling falls into this informal sector. On average South Africa recovers about 52 percent of all recoverable paper and 26 percent of all recoverable plastic per annum. These figures are low when compared with developed countries where up to 90 percent of recoverable paper is recovered. As recycling creates job and income generating opportunities, it thus has a vital role to play in poverty alleviation. The research examines the role of subsistence waste pickers in the recycling industry in South Africa. The research was qualitative and exploratory in nature. Data for this study was gathered through 30 semi-structured interviews with key stakeholders in the recycling industry. In total, informal waste pickers provide at least 84 percent of all recyclable materials in Johannesburg through merchants, recyclers and producers of recyclable material in Johannesburg. Informal waste pickers bring considerable socio-economic benefits to countries around the globe, providing work for the unskilled, providing a constant supply of secondary raw materials to the local manufacturing industries and significantly reducing the quantity of waste to landfill sites. However, the research will show that even in the best situations, waste pickers suffer ergonomic problems due to the physically taxing nature of their job, as well as psychological and social disadvantages stemming from their low social status. / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted
16

The fundamental limits of recycling : from minerals processing to computer aided design of automobiles and other consumer goods

Reuter, Markus Andreas 12 1900 (has links)
Thesis (PhD (Process Engineering)--Stellenbosch University, 2006. / My applied engineering research and industrial application work of the past 20 years is presented in this dissertation. It is the conjecture of my work that only if thorough first principles knowledge of the depth of process metallurgy and recycling is available, can meaningful first principles environmental models be developed. These models can then evaluate technology, provide well argued and first principles environmental information to our tax paying consumer society as well as to legislators and environmentalists. Only through this path can one estimate the limits of recycling and its technology, hence evaluate the true boundaries of sustainability. My work with students has presently culminated in the detailed modelling and simulation of recycling systems for post-consumer goods. Notably the models are finding an application in the prediction of legally required recycling rates for automobiles. The models provide first principles arguments for less stringent EU recycling legislation and the integration of the first principles models in computer aided design tools of the automotive industry as part of a large EU 6th Framework (project managed by Volkswagen and the other European car producers). Presently these models are also being converted to model the Waste Electric and Electronic Equipment (WEEE) as well as water recycling systems respectively, both for industry in The Netherlands. This unique rigorous integration of systems engineering, reactor technology and process control theory is the basis of all my work to describe recycling systems as dynamic feedback control loops. My large body of acquired industrial knowledge renders these models practical and can hence be used by the automotive and recycling industries. The origins of this work may be found in the various cited publications and reports to industry by myself (due to my close association with industry as well as industrial experience) over the past 20 years as well as the work of my students, covering topics such as: • system optimization models for flotation, mineral beneficiation and recycling systems and applying these for design for recycling and argue for better/improved first-principles based legislation, • industrial measurement, modelling and simulation of industrial extractive process pyrometallurgical reactors as well waste incinerators and recycling plants, • various activities in other areas such as hydrometallurgy, clean and new breakthrough technology, and • process control of industrial metallurgical reactors by among others the application of artificial intelligence techniques. All the ideas of the last years have been worked out with students and have been summarized in our book: “The Metrics of Material and Metal Ecology, Harmonizing the resource, technology and environmental cycles”.
17

The values of recycling, resources and risk management in Hong Kong /

Wong, Wai-han, Mimi. January 1998 (has links)
Thesis (M. Sc.)--University of Hong Kong, 1998. / Includes bibliographical references (leaf 99-102).
18

Exploration of blockchain technology in the Swedish textile recycling industry : Opportunities and challenges for traceability

Dorf, Vendela, Jonsson, Amanda, Dalal, Aadit January 2022 (has links)
Purpose: The purpose of this study is to explore the potential of technologies for traceability within the Swedish textile recycling industry. This study further aims to investigate the status of information collection and management in the textile recycling industry and the factors which are affecting the implementation of different traceability technologies, such as blockchain technology.   Design/ Methodology/ Approach: This study followed a qualitative exploratory approach as there is little prior knowledge regarding usage of traceability technologies, such as blockchain technology in the Swedish textile recycling industry. Primary data was collected by semi-structured interviews, and it was analysed through thematic analysis. Purposive sampling was used to collect relevant data. The sample included experts from the academia and industry, who have knowledge in the field of textile recycling and traceability technologies.   Findings: The findings suggest that there is no available information collection and management systems that enable efficient recycling processes. Moreover, there is a lack of infrastructure for collecting and sorting the textile waste, cost and technological challenges hampering the potential of efficient textile recycling and the possibility to create an efficient circular supply chain in Sweden. There are four factors which affect the opportunities and challenges for implementation of traceability technologies, such as blockchain technology, these are: management and decision making, integration and collaboration, rules and regulations and value creation through blockchain in the textile recycling industry.   Implications: This study may contribute to reshaping the traditional view on where traceability technologies can be implemented to create efforts to enhance the circular economy principles, as suggested by literature from the previous stages in a supply chain. This study suggests that blockchain technology may enhance information sharing in a circular supply chain within the textile recycling industry. It further shows that the textile recyclers have the potential to implement blockchain technology from their stage to minimise the information gaps which are currently existing.   Originality/ Value: The academic literature lacks practical cases and exploration regarding the usage of traceability technologies such as blockchain technology at the textile recycling stage and this study tries to explore if it would be beneficial for the textile recycling industry in Sweden.
19

The values of recycling, resources and risk management in Hong Kong

Wong, Wai-han, Mimi., 黃惠嫻. January 1998 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
20

Recycling business in Hong Kong: an economic and environmental perspective

Kwan Cheng, Lai-man, Heidi., 關鄭麗敏. January 1993 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

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