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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.
1

Viabilidade da produção de carvão ativado a partir de resíduos alternativos

Lúcia Paula Martins Prado de Macêdo 10 December 2012 (has links)
As fibras-de-coco (Cocos nucifera) quando destinadas em aterros sob condições anaeróbias, provocam a emissão de metano, um dos mais importantes gases de efeito estufa. Neste trabalho, são propostos usos das fibras-de-coco misturadas em diferentes relações com resíduos alternativos, com o objetivo de mitigar os impactos provocados pelos resíduos, possibilitando a produção de carvão ativado. Como alternativa, fez-se a proposição de se utilizar a relação coco/resíduo igual a 100/0, 75/25, 50/50, 25/75 e 0/100, coletando-se os resíduos de laranja, banana, caju e acerola (bagaço e cascas) nos locais apropriados. Para análise imediata foram determinados os teores de cinzas (a 600 C) e umidade (a 105 C) segundo a norma ASTM D-1762/64, os teores de material volátil (a cinza em mufla a 950 C) e de carbono fixo, segundo a norma ASTM D-1762/64, e o poder calorífico, segundo a norma ABNT-NBR 8633/84, dos diversos tratamentos. Os dados obtidos foram submetidos à análise estatística onde foi possível elaborar gráficos que demonstrassem a relação entre as determinações realizadas, indicando a mistura da fibra-de-coco com acerola e com banana a mais promissora. / The coconut fibers (Cocos nucifera) when intended in landfills under anaerobic conditions, cause the emission of methane, one of the most important greenhouse gas. In this work, is proposed the use of coconut fiber mixed in different ratios with alternative waste in order to mitigate the impacts caused by waste, enabling the production of new products. As an alternative, it was proposed to do the relationship coconut / residue equal to 100/0, 75/25 50/50 25/75 and 0/100 by collecting the waste orange, banana, and cashew acerola (pulp and peel) in the appropriate places. For immediate analysis were determined the ash content (600 C) and humidity (105 C)ASTM D-1762/64, the levels of volatile material (ash in a muffle furnace at 950 C) and fixed carbon, ASTM D-1762/64, and calorific power, according to ABNT-NBR 8633/84, the various treatments. The data were submitted to statistical analyzes where it was possible to draw graphs that demonstrate the relationship among the measurements performed, indicating the mixture of coconut fiber with cherry and banana the most promising.
2

Viabilidade da produção de carvão ativado a partir de resíduos alternativos

Macêdo, Lúcia Paula Martins Prado de 10 December 2012 (has links)
Made available in DSpace on 2017-06-01T18:20:38Z (GMT). No. of bitstreams: 1 dissertacao_paula_macedo.pdf: 713310 bytes, checksum: 941c18a8ca32e16587bf1e5a6169267d (MD5) Previous issue date: 2012-12-10 / The coconut fibers (Cocos nucifera) when intended in landfills under anaerobic conditions, cause the emission of methane, one of the most important greenhouse gas. In this work, is proposed the use of coconut fiber mixed in different ratios with alternative waste in order to mitigate the impacts caused by waste, enabling the production of new products. As an alternative, it was proposed to do the relationship coconut / residue equal to 100/0, 75/25 50/50 25/75 and 0/100 by collecting the waste orange, banana, and cashew acerola (pulp and peel) in the appropriate places. For immediate analysis were determined the ash content (600 ° C) and humidity (105 ° C)ASTM D-1762/64, the levels of volatile material (ash in a muffle furnace at 950 ° C) and fixed carbon, ASTM D-1762/64, and calorific power, according to ABNT-NBR 8633/84, the various treatments. The data were submitted to statistical analyzes where it was possible to draw graphs that demonstrate the relationship among the measurements performed, indicating the mixture of coconut fiber with cherry and banana the most promising. / As fibras-de-coco (Cocos nucifera) quando destinadas em aterros sob condições anaeróbias, provocam a emissão de metano, um dos mais importantes gases de efeito estufa. Neste trabalho, são propostos usos das fibras-de-coco misturadas em diferentes relações com resíduos alternativos, com o objetivo de mitigar os impactos provocados pelos resíduos, possibilitando a produção de carvão ativado. Como alternativa, fez-se a proposição de se utilizar a relação coco/resíduo igual a 100/0, 75/25, 50/50, 25/75 e 0/100, coletando-se os resíduos de laranja, banana, caju e acerola (bagaço e cascas) nos locais apropriados. Para análise imediata foram determinados os teores de cinzas (a 600 ºC) e umidade (a 105 ºC) segundo a norma ASTM D-1762/64, os teores de material volátil (a cinza em mufla a 950 ºC) e de carbono fixo, segundo a norma ASTM D-1762/64, e o poder calorífico, segundo a norma ABNT-NBR 8633/84, dos diversos tratamentos. Os dados obtidos foram submetidos à análise estatística onde foi possível elaborar gráficos que demonstrassem a relação entre as determinações realizadas, indicando a mistura da fibra-de-coco com acerola e com banana a mais promissora.
3

Modélisation des flux de biomasse et de nutriments dans les territoires agricoles : simulation et évaluation de scénarios appliqués à un cas d’étude en France / Modelling biomass and nutrient flows in agro-food systems at the local scale : scenario simulation and assessment in a French case-study

Fernandez mena, Hugo 19 December 2017 (has links)
Nourrir une population mondiale croissante dans un contexte de changements globaux pose de nouveaux défis à l’agriculture en termes d’efficience de production et d’impacts environnementaux. Rendre les systèmes agro-alimentaires plus soutenables nécessite de mieux recycler la biomasse et les nutriments, c’est-à-dire de tendre vers des flux de fertilisants, de produits végétaux, d’aliments du bétail, de coproduits et de déchets plus circulaires. À ce titre, il est nécessaire de développer de nouveaux outils pour mieux explorer et évaluer les échanges de matières entre les fermes et leurs partenaires économiques amont et aval dans les territoires. Dans le travail présent, l’état de l’art concernant les méthodes d’analyse, de modélisation et d’évaluation environnementale des flux de biomasse et d’éléments minéraux à différentes échelles est réalisé. Le modèle multi-agents FAN (« Flows in Agricultural Network») qui simule les flux des matières entre les fermes et leurs partenaires économiques dans les territoires agricoles a été développé. Les processus de FAN sont expliqués en détail et une analyse de sensibilité des variables clefs est présentée. Par ailleurs, le modèle FAN a été appliqué à un cas d’études en France pour évaluer la performance des scénarios contrastés visant à améliorer l’efficience d’utilisation des éléments minéraux, développer le recyclage de la matière, favoriser la production du biogaz ou reconcevoir les systèmes de production. Les sorties de simulations des scénarios sont analysées en termes de production alimentaire et énergétique, de flux de matières et de logistique, de cycle des nutriments et d’émissions de gaz à effet de serre. Ce travail montre l’utilité des outils de prospective et modèles multi-agents pour améliorer la durabilité des systèmes agricoles et des chaines alimentaires, pour créer et évaluer des solutions collectives tendant vers l’économie circulaire et pour prendre en charge les interactions entre acteurs économiques au sein des chaines et filières alimentaires complexes. / Feeding the growing global population in a context of global change raises new challenges for agriculture regarding its production efficiency and impacts on natural resources. Solutions for towards farming sustainability require to improve nutrient and biomass recycling in agro-food systems, i.e. to move from linear to more circular flows of fertilizers, crop products, feedstuff, by-products and organic wastes. Innovative tools exploring material exchanges between farms and their upstream and downstream partners in agro-food systems at the local scale are needed. In the present work, the state of the art about analysis methods, models and environmental tools addressing nutrient and biomass flows at different scales is reviewed. The FAN (“Flows in Agricultural Network”) model, an agent-based model that simulates a range of material flows among farms and their partners within agricultural districts is developed. FAN processes are explained in details and a sensitivity analysis to some key variables is performed. In addition, the FAN model is applied to a French case-study to assess the performances of contrasted scenarios aiming to enhance nutrient use efficiency, recycling strategies, biogas production and system redesign. The outcomes from the scenario simulation are analyzed are assessed in terms of food provisioning, nutrient cycling and greenhouse gas emissions. This work shows the usefulness of prospective, agent-based tools for greater farming and food-chain sustainability, to design and evaluate collective solutions for circular economy and to account for interactions among economic actors within complex agro-food systems.
4

Resíduos de coco, acerola e caju para produção de carvão ativado

Ricardo Vandré Trótski Oliveira Silva 25 February 2015 (has links)
Com o crescimento das atividades industriais e da população, aumentam também a quantidade de resíduos gerados que ocasiona problemas ambientais. No Brasil, produtor de bens na agroindústria, os problemas causados pelo acúmulo e destinação inadequada dos resíduos sólidos é de grande porte. A partir dessa problemática são criados mecanismos que incentivam a reutilização e reciclagem dos resíduos. É buscando desenvolver tecnologia inédita de matérias-primas alternativas que se produziu carvão ativado a partir de resíduos de coco, acerola e caju. Primeiramente coletou-se a fibra-de-coco seco e bagaços/cascas de acerola e do caju para posterior preparação desse material através da impregnação com ZnCl2, da ativação química e da realização de um teste de avaliação da eficiência do carvão. Foi produzido carvão ativado com todas as amostras, onde a aplicação na amostra de água coletada no rio Capibaribe (perto do túnel Chico Science), Recife, Pernambuco, apresentou redução da turbidez em 97,3 % usando o tratamento com 25 % de fibra-de-coco + 75 % de caju. / With the growth of industrial activities and population, also increases the amount of generated waste which causes environmental problems. In Brazil, a major producer of goods in the agricultural industry, the problems caused by the accumulation and improper disposal of solid waste are large. From this problematic, mechanisms that encourage the reuse and recycling of waste are created. It is seeking to develop new technology of alternative raw materials that are produced activated carbon from coconut waste, barbados cherry and cashew. Primarily, the collection of fiber-to-dry coconut and cake/shells from barbados cherry and cashew for later preparation of this material by impregnation with ZnCl2, chemical activation and conducting an evaluation test coal efficiency. The result, within all samples, was an activated carbon where the application in the water sample collected from the Capibaribe River (near Chico Science tunnel), Recife, presented a decrease in turbidity in 97.3% using treatment with 25% fiber- coconut + 75% cashew.
5

Resíduos de coco, acerola e caju para produção de carvão ativado

Silva, Ricardo Vandré Trótski Oliveira 25 February 2015 (has links)
Made available in DSpace on 2017-06-01T18:20:45Z (GMT). No. of bitstreams: 1 ricardo_vandre_trotski_oliveira_silva.pdf: 610833 bytes, checksum: 744d83d7588313cd4ff2b78eb59399bf (MD5) Previous issue date: 2015-02-25 / With the growth of industrial activities and population, also increases the amount of generated waste which causes environmental problems. In Brazil, a major producer of goods in the agricultural industry, the problems caused by the accumulation and improper disposal of solid waste are large. From this problematic, mechanisms that encourage the reuse and recycling of waste are created. It is seeking to develop new technology of alternative raw materials that are produced activated carbon from coconut waste, barbados cherry and cashew. Primarily, the collection of fiber-to-dry coconut and cake/shells from barbados cherry and cashew for later preparation of this material by impregnation with ZnCl2, chemical activation and conducting an evaluation test coal efficiency. The result, within all samples, was an activated carbon where the application in the water sample collected from the Capibaribe River (near Chico Science tunnel), Recife, presented a decrease in turbidity in 97.3% using treatment with 25% fiber- coconut + 75% cashew. / Com o crescimento das atividades industriais e da população, aumentam também a quantidade de resíduos gerados que ocasiona problemas ambientais. No Brasil, produtor de bens na agroindústria, os problemas causados pelo acúmulo e destinação inadequada dos resíduos sólidos é de grande porte. A partir dessa problemática são criados mecanismos que incentivam a reutilização e reciclagem dos resíduos. É buscando desenvolver tecnologia inédita de matérias-primas alternativas que se produziu carvão ativado a partir de resíduos de coco, acerola e caju. Primeiramente coletou-se a fibra-de-coco seco e bagaços/cascas de acerola e do caju para posterior preparação desse material através da impregnação com ZnCl2, da ativação química e da realização de um teste de avaliação da eficiência do carvão. Foi produzido carvão ativado com todas as amostras, onde a aplicação na amostra de água coletada no rio Capibaribe (perto do túnel Chico Science), Recife, Pernambuco, apresentou redução da turbidez em 97,3 % usando o tratamento com 25 % de fibra-de-coco + 75 % de caju.

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