In this study, an entropy generation minimization procedure is employed to optimize the overall performance (thermal and hydrodynamic) of isolated fin geometries and pin-fin heat sinks. This allows the combined effects of thermal resistance and pressure drop to be assessed simultaneously as the heat sink interacts with the surrounding flow field. New general expressions for the entropy generation rate are developed using mass, energy, and entropy balances over an appropriate control volume. The formulation for the dimensionless entropy generation rate is obtained in terms of fin geometry, longitudinal and transverse pitches, pin-fin aspect ratio, thermal conductivity, arrangement of pin-fins, Reynolds and Prandtl numbers. It is shown that the entropy generation rate depends on two main performance parameters, i. e. , thermal resistance and the pressure drop, which in turn depend on the average heat transfer and friction coefficients. These coefficients can be taken from fluid flow and heat transfer models. An extensive literature survey reveals that no comprehensive analytical model for any one of them exists that can be used for a wide range of Reynolds number, Prandtl number, longitudinal and transverse pitches, and thermal conductivity. This study is one of the first attempts to develop analytical models for the fluid flow and heat transfer from single pins (circular and elliptical) with and without blockage as well as pin-fin arrays (in-line and staggered). These models can be used for the entire laminar flow range, longitudinal and transverse pitches, any material (from plastic composites to copper), and any fluid having Prandtl numbers (≥0. 71). In developing these models, it is assumed that the flow is steady, laminar, and fully developed. Furthermore, the heat sink is fully shrouded and the thermophysical properties are taken to be temperature independent. Using an energy balance over the same control volume, the average heat transfer coefficient for the heat sink is also developed, which is a function of the heat sink material, fluid properties, fin geometry, pin-fin arrangement, and longitudinal and transverse pitches. The hydrodynamic and thermal analyses of both in-line and staggered pin-fin heat sinks are performed using parametric variation of each design variable including pin diameter, pin height, approach velocity, number of pin-fins, and thermal conductivity of the material. The present analytical results for single pins (circular and elliptical) and pin-fin-arrays are in good agreement with the existing experimental/numerical data obtained by other investigators. It is shown that the present models of heat transfer and pressure drop can be applied for a wide range of Reynolds and Prandtl numbers, longitudinal and transverse pitches, aspect ratios, and thermal conductivity. Furthermore, selected numerical simulations for a single circular cylinder and in-line pin-fin heat sink are also carried out to validate the present analytical models. Results of present numerical simulations are also found to be in good agreement.

In this study, an entropy generation minimization procedure is employed to optimize the overall performance (thermal and hydrodynamic) of isolated fin geometries and pin-fin heat sinks. This allows the combined effects of thermal resistance and pressure drop to be assessed simultaneously as the heat sink interacts with the surrounding flow field. New general expressions for the entropy generation rate are developed using mass, energy, and entropy balances over an appropriate control volume. The formulation for the dimensionless entropy generation rate is obtained in terms of fin geometry, longitudinal and transverse pitches, pin-fin aspect ratio, thermal conductivity, arrangement of pin-fins, Reynolds and Prandtl numbers. It is shown that the entropy generation rate depends on two main performance parameters, i. e. , thermal resistance and the pressure drop, which in turn depend on the average heat transfer and friction coefficients. These coefficients can be taken from fluid flow and heat transfer models. An extensive literature survey reveals that no comprehensive analytical model for any one of them exists that can be used for a wide range of Reynolds number, Prandtl number, longitudinal and transverse pitches, and thermal conductivity. This study is one of the first attempts to develop analytical models for the fluid flow and heat transfer from single pins (circular and elliptical) with and without blockage as well as pin-fin arrays (in-line and staggered). These models can be used for the entire laminar flow range, longitudinal and transverse pitches, any material (from plastic composites to copper), and any fluid having Prandtl numbers (≥0. 71). In developing these models, it is assumed that the flow is steady, laminar, and fully developed. Furthermore, the heat sink is fully shrouded and the thermophysical properties are taken to be temperature independent. Using an energy balance over the same control volume, the average heat transfer coefficient for the heat sink is also developed, which is a function of the heat sink material, fluid properties, fin geometry, pin-fin arrangement, and longitudinal and transverse pitches. The hydrodynamic and thermal analyses of both in-line and staggered pin-fin heat sinks are performed using parametric variation of each design variable including pin diameter, pin height, approach velocity, number of pin-fins, and thermal conductivity of the material. The present analytical results for single pins (circular and elliptical) and pin-fin-arrays are in good agreement with the existing experimental/numerical data obtained by other investigators. It is shown that the present models of heat transfer and pressure drop can be applied for a wide range of Reynolds and Prandtl numbers, longitudinal and transverse pitches, aspect ratios, and thermal conductivity. Furthermore, selected numerical simulations for a single circular cylinder and in-line pin-fin heat sink are also carried out to validate the present analytical models. Results of present numerical simulations are also found to be in good agreement.

Made available in DSpace on 2015-05-14T12:09:07Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2105205 bytes, checksum: 3d2f503ba201bc7c9e911070cd74f7a9 (MD5) Previous issue date: 2012-04-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Given the high index of construction in the city of João Pessoa, in northeast Brazil and the frequent irregular disposal of its residues, the objective of this work was to study the generation rate of construction wastes (CW) based on constructed area of the building, so that a more effective inspection can be implemented by the proper instances. A sample of building was choose among those under construction in João Pessoa and the collection of data regarding to their CW volume generated and other characteristics of the building were performed. From the volume of CW discharged by the building companies, the generation rate was calculated based on a unit mass of 1.025 kg/m³ determined in this work. The sample was divided into two groups: (1) control group and (2) non-control group. The control group was made up by the building in which the author worked as inspector, visiting them on a daily base. Analysis of variance showed that the generation rate from control group did not differ from that from non-control group, showing that the methodology applied for data collection can be considered a valid one. Results showed that the generation rate of class A (CONAMA Resolution 307) CW in João Pessoa is 86,27 kg/m² and that there were no significant difference between that from dwellings and non-dwellings buildings. The 90% confidence interval for the arithmetic mean was calculated and the lower and upper limits were 62,31 and 136,02 kg/m², respectively. Based on these results the control on the generation and disposal of CW can be done more efficiently by municipal authorities. / Diante do crescimento acelerado da construção civil em João Pessoa e da disposição irregular dos RCC gerados, determinou-se a taxa de geração de RCC em kg/m² de área construída, visando auxiliar ações de fiscalização e acompanhamento da destinação final dos RCC. Foi escolhida uma amostra das edificações em fase de construção em João Pessoa para coleta das características de cada obra e do volume gerado de RCC. Durante a fase de construção, foi passado para cada empresa uma ficha de acompanhamento e anotação do volume de descarte dos RCC ao longo de todo o cronograma de execução da construção. A partir do volume descartado pelas construtoras, foi determinada a massa de RCC gerado em cada obra, utilizando a massa unitária de 1.025 kg/m³, obtida através da média das pesagens de RCC. Foi feita uma análise estatística dos dados utilizando dois grupos: grupos das obras controle, sendo estas as que foram acompanhadas pelo mestrando diariamente, e o grupo das demais obras de modo a validar a amostra. A amostra foi considerada válida e assim, foi determinada a taxa de geração de RCC de todas as obras concluídas. Os resultados indicaram uma taxa de geração de RCC de resíduos classe A de 86,27 kg/m², não tendo sido encontradas diferenças significativas entre tal taxa em obras particulares (residenciais) e obras públicas. Foram calculados os limites inferior e superior 90% de confiança para a média aritmética da taxa de geração, sendo estes valores de 62,31 e 136,02 kg/m², respectivamente. A partir desses valores, o controle da geração e disposição de RCC pode ser realizado pelos órgãos competentes, dando o indicativo de quais obras podem estar infringindo a Lei Municipal 11.376, bem como a resolução CONAMA 307.

Made available in DSpace on 2015-05-14T12:09:02Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1919143 bytes, checksum: faa87eecc90844612c31c660855f23e5 (MD5) Previous issue date: 2011-03-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / A long time ago garbage was not seen as a problem, since it was generated in few quantities and most of it was composed of biodegradable materials, which were easily transformed by nature. However, population has been growing, moving from rural to urban area, its habits have been changing, including the consumption of industrialised products, and so that the amount and nature of garbage have been changing. This increase in the amount of garbage have been causing a large problem to the cities, since most of them does not succeed in giving proper final destination to the wastes, mainly because of the costs involved in the service. For the waste collection service, the municipality generally tax the population by means of the TCR Taxa de Coleta de Residuos (Waste Collection Tax). This TCR is very questioned, mainly because its base of calculation, that is not the amount of wastes generated, but generally the constructed area of the house. Many people consider unfair the tax, since it may happen that a house may be charged with a high tax value because of its large constructed area, but may not necessarily generate a large amount of waste. This study aims to elaborate a mathematical model to estimate de amount of solid wastes generated in a house and so, to propose an alternative methodology for the TCR calculation. Another aim of the study is to investigate the variations on the amount of wastes generated along the days of week, so that the collection fleet can be optimized. The methodological procedures consisted in diary weighting of the solids wastes, along with the readings of water and electricity consumption in three houses in the city of João Pessoa, northeast Brazil. Results have shown that the per capita domestic solid waste generation rate was 800 g/day, which is close to the value suggested in the literature. In comparison to other similar study but performed in flats rather than in houses, the generation rates herein reported were 60% higher in relation to that reported for flats, which may be associated with the fact that gardens and backyards, that occurs only in houses (not in flats), respond for part of such generation. With regards to the variations in the waste generation along the days of week, it was found that there were not significant differences between most the cases. The only exceptions were between Monday and the other days (exceptionally Saturday), between Saturday and Tuesday, and between Sunday and the other days, exceptionally to the Tuesday. By the other side, in João Pessoa very little of collection is done on Sunday, so that the mentioned difference is not important. For the case in which the wastes generated on Sunday are collected in conjunction with those generated on Monday, the amount totalizes 1,9 times those generated along the other days (in average) and so that the collection fleet must be increased by this factor (1,9). Results have also shown that it is possible to estimate the amount of solid wastes generated in a house from its population and water consumption. Based on this model, an alternative methodology for the TCR was proposed, which consider not the constructed area but the amount of wastes estimated. / Há muito tempo, os resíduos não eram vistos como um problema, pois ele era gerado em menor quantidade e sua maior parte era constituída por materiais biodegradáveis, facilmente transformados pela natureza. No entanto, a população vem crescendo bastante, migrando da área rural para as cidades, seus hábitos vêm mudando, aumentando o consumo de produtos industrializados, e com isso passou a existir nos resíduos as embalagens longa vida, sacos plásticos, isopor, latas, dentre outros materiais, os quais demoram para ser degradados. Esse aumento na quantidade de resíduos sólidos vem causando graves transtornos para as cidades, pois grande parte delas não consegue dar uma destinação final adequada aos mesmos, devido a diversos fatores, tais como: o custo elevado para a coleta dos resíduos, a falta de locais apropriados para a construção de aterros sanitários, bem como o alto valor necessário para a manutenção desses aterros, entre outros. Para a execução dos serviços de limpeza pública, as Prefeituras costumam cobrar uma taxa, geralmente denominada TCR Taxa de Coleta de Resíduos. Acontece que a cobrança da TCR é bastante questionada, principalmente por não ter por base de cálculo a quantidade de resíduos efetivamente gerada, mas sim, geralmente, a área do domicílio. Muitos consideram que esta forma de cobrança é injusta, uma vez que, nesta forma de cálculo, pode ocorrer de uma residência pagar uma elevada TCR só por ter uma área grande, apesar de poder gerar poucos resíduos. O presente trabalho busca encontrar um modelo matemático para se estimar a quantidade de RSD gerada em residências unifamiliares, a partir de diversos parâmetros, e com isso propor uma nova metodologia a ser adotada para o cálculo da TCR. Outra contribuição importante é o estudo da variação semanal de resíduos gerados, procurando verificar se há diferenças significativas entre as quantidades de resíduos geradas nos diversos dias da semana, o que pode ser útil no dimensionamento e otimização da frota de coleta. A metodologia adotada consistiu na pesagem dos resíduos sólidos domiciliares (RSD) diariamente e, logo em seguida, na medição dos consumos de água e energia elétrica, sendo estes verificados através do hidrômetro e do medidor de energia elétrica, respectivamente, em três residências na cidade de João Pessoa-PB. Os resultados mostraram que a taxa de geração de resíduos sólidos para residências unifamiliares na cidade de João Pessoa é de aproximadamente 800 g/hab.dia, valor este próximo ao sugerido pela literatura especializada. Comparando-se os resultados deste trabalho com o de Athayde Jr. et al. (2008), desenvolvido junto a edificações multifamiliares (edifícios de apartamentos), constatou-se que a taxa de geração per capita de RSD é maior (60% maior) em residências unifamiliares (casas) do que em edificações multifamiliares (apartamentos). Este fato pode estar relacionado à existência de jardins e quintais no primeiro tipo de residência, os quais não existem em apartamentos. Com relação à variação da taxa de geração de RSD, percebeu-se que não existem diferenças significativas entre a maioria dos dias da semana. As únicas exceções foram a segunda-feira, com tal taxa significativamente maior que os demais dias da semana (exceto o sábado), a do sábado, que foi significativamente maior daquela da terça-feira, e a do domingo, que foi significativamente menor que a dos demais dias da semana, exceto a da terça-feira. Por outro lado, como é comum não haver coleta de RSD no domingo, situação em que os resíduos gerados neste dia são coletados juntamente com os gerados na segunda-feira, a soma dos RSD gerados nestes dois dias é significativamente maior que as quantidades geradas nos demais dias da semana. Neste caso, justifica-se um reforço na frota de coleta na segunda-feira de 1,9 vezes a média dos outros dias. Os resultados mostraram ser possível estimar a quantidade de RSD gerados em um domicílio a partir de seus indicadores de consumo (água e energia elétrica). Dentre os indicadores estudados, apenas o consumo de água se mostrou satisfatório para este fim. Dessa forma, foi proposto um modelo matemático para estimativa da geração de RSD que teve como variável independente o consumo de água, além da população do domicílio. Com o modelo proposto foi possível elaborar uma metodologia alternativa para o cálculo da TCR, baseando-se não mais na área construída do domicílio, mas sim na quantidade estimada de RSD.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21965号 / 工博第4620号 / 新制||工||1720(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 酒井 伸一, 教授 勝見 武, 准教授 平井 康宏 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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Healthcare waste management is very important due to its hazardous nature that can cause risk to human health and the environment. The study wished to determine the amount of healthcare waste generated in 15 public health centres and 3 hospitals and evaluate the healthcare waste management practices in Addis Ababa City Administration. The aim of the study was to develop a manual for healthcare facilities based on the findings on healthcare waste management practice, quantification and intervention. Data was obtained from questionnaires distributed to 636 randomly selected healthcare professionals, ancillary staff and managers and by means of surveying the facilities. The mean HCW generation rate was 10.64 + 5.79 kg/day, of which 37.26% (3.96 + 2.017kg/day) was general waste and 62.74% (6.68 + 4.293 kg/day) was hazardous waste from the surveyed health centres. HCW generation and quantification was not measured and documented in any of the HCFs. Quantifying HCW would help determine the type of waste as well as the HCFs that generate the highest and lowest HCW, which could have implications for resource allocation in managing HCW. Segregation of different types of wastes was not regularly done. Some HCFs had separate storage areas for HCW and separate containers for hazardous and nonhazardous waste. In some instances, however, the containers were not clearly marked. Regarding storage, some of the HCFs had interim storage sites and HCW disposal sites. Several interim storage facilities lacked security and surveillance and were not cleaned after collection. In addition, HCW remained at the interim storage facilities for more than 48 hours before final disposal. The main forms of on-site treatment of HCW before disposal were burning, crushing sharps, sterilisation and chemical disinfection. The most common treatment method used for HCW was incineration. Most HCW handlers had not received adequate training; did not wear PPE, and did not take precautionary measures, such as washing their hands and heavy duty gloves after handling HCW. The researcher developed a manual for effective HCW management and training of HCW handlers. Based on the findings, the study makes recommendations for policy, education, HCW management, including generation, segregation, storage, transportation and disposal, and further research. / Health Studies / D. Litt. et Phil. (Health Studies)