4 resultados para Biometano,upgrading,biogas

em Digital Commons at Florida International University


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The purpose of this study is about to survey the effectiveness of English teaching in universities/colleges in Taiwan and provide suggestions to the educational authorities for upgrading or improving the English language teaching techniques or methods currently in use. On the one hand, the suggestions of English teachers in universities/colleges are the main concerns in this study. On the other hand, equal attention is given to the opinions and learning attitudes of the students, including the interaction between the teachers and the students.^ A social investigation methodology, consisting of questionnaire and data analysis, is devoted to this evaluation and analysis of teaching effectiveness. Among the significant findings reported in this study is the fact that both students and teachers consider evaluation of teaching effectiveness as a very important aspect of English Language programs at the university/college level. Another significant finding is that students are less concerned about the grades earned or awarded in English Language courses and more concerned about how much they learned in these classes.^ The analysis and suggestions based on the results for English teaching evaluation of universities/colleges in this dissertation can help teachers modify their teaching techniques and methods, the students to adjust their learning attitudes, and the authorities to schematize the English teaching plan that can facilitate the teaching goals to be realized. ^

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Low-income settlements have high incidences of social and environmental problems due to lack of government intervention; low-income settlements usually rely on community organizations or non-governmental entities to survive. In order to improve the quality of life in these communities, urban upgrading plans must be designed to achieve adequate living conditions. ^ This thesis proposes an urban intervention plan for a low-income settlement called Vila da Barca. This thesis contains three document parts. The first part defines the country, city, and settlement background, including housing and urban issues. The second part contains information gathered from case studies and theories on how similar urban cities around the world have solved their urban development problems. Lastly, the third part proposes a residential development plan that enhances the citizen's needs, such as shelter and safety. The proposed set of criteria applicable to Vila da Barca will serve as an example for other urban intervention projects. ^

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Siloxanes are widely used in personal care and industrial products due to their low surface tension, thermal stability, antimicrobial and hydrophobic properties, among other characteristics. Volatile methyl siloxanes (VMS) have been detected both in landfill gas and biogas from anaerobic digesters at wastewater treatment plants. As a result, they are released to gas phase during waste decomposition and wastewater treatment. During transformation processes of digester or landfill gas to energy, siloxanes are converted to silicon oxides, leaving abrasive deposits on engine components. These deposits cause increased maintenance costs and in some cases complete engine overhauls become necessary. The objectives of this study were to compare the VMS types and levels present in biogas generated in the anaerobic digesters and landfills and evaluate the energetics of siloxane transformations under anaerobic conditions. Siloxane emissions, resulting from disposal of silicone-based materials, are expected to increase by 29% within the next 10 years. Estimated concentrations and the risk factors of exposure to siloxanes were evaluated based on the initial concentrations, partitioning characteristics and persistence. It was determined that D4 has the highest risk factor associated to bioaccumulation in liquid and solid phase, whereas D5 was highest in gas phase. Additionally, as siloxanes are combusted, the particle size range causes them to be potentially hazardous to human health. When inhaled, they may affix onto the alveoli of the lungs and may lead to development of silicosis. Siloxane-based COD-loading was evaluated and determined to be an insignificant factor concerning COD limits in wastewater. Removal of siloxane compounds is recommended prior to land application of biosolids or combustion of biogas. A comparison of estimated costs was made between maintenance practices for removal of siloxane deposits and installation/operation of fixed-bed carbon absorption systems. In the majority of cases, the installation of fixed-bed adsorption systems would not be a feasible option for the sole purpose of siloxane removal. However they may be utilized to remove additional compounds simultaneously.

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Siloxanes are widely used in personal care and industrial products due to their low surface tension, thermal stability, antimicrobial and hydrophobic properties, among other characteristics. Volatile methyl siloxanes (VMS) have been detected both in landfill gas and biogas from anaerobic digesters at wastewater treatment plants. As a result, they are released to gas phase during waste decomposition and wastewater treatment. During transformation processes of digester or landfill gas to energy, siloxanes are converted to silicon oxides, leaving abrasive deposits on engine components. These deposits cause increased maintenance costs and in some cases complete engine overhauls become necessary. ^ The objectives of this study were to compare the VMS types and levels present in biogas generated in the anaerobic digesters and landfills and evaluate the energetics of siloxane transformations under anaerobic conditions. Siloxane emissions, resulting from disposal of silicone-based materials, are expected to increase by 29% within the next 10 years. Estimated concentrations and the risk factors of exposure to siloxanes were evaluated based on the initial concentrations, partitioning characteristics and persistence. It was determined that D4 has the highest risk factor associated to bioaccumulation in liquid and solid phase, whereas D5 was highest in gas phase. Additionally, as siloxanes are combusted, the particle size range causes them to be potentially hazardous to human health. When inhaled, they may affix onto the alveoli of the lungs and may lead to development of silicosis. Siloxane-based COD-loading was evaluated and determined to be an insignificant factor concerning COD limits in wastewater. ^ Removal of siloxane compounds is recommended prior to land application of biosolids or combustion of biogas. A comparison of estimated costs was made between maintenance practices for removal of siloxane deposits and installation/operation of fixed-bed carbon absorption systems. In the majority of cases, the installation of fixed-bed adsorption systems would not be a feasible option for the sole purpose of siloxane removal. However they may be utilized to remove additional compounds simultaneously.^