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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.
461

Avaliação da qualidade das águas subterrâneas e do solo em áreas de disposição final de resíduos sólidos urbanos em municípios de pequeno porte: aterro sanitário em valas / Assessment of the quality of groundwater and soil in areas of final disposal of municipal solid waste in small cities: landfills in ditches

Cristiano Kenji Iwai 27 March 2012 (has links)
O gerenciamento adequado dos resíduos sólidos contribui de forma inequívoca com a sustentabilidade urbana e com a saúde ambiental e humana. São conhecidas as dificuldades na destinação final adequada dos resíduos sólidos urbanos em todo o Brasil, principalmente em municípios de pequeno porte, nos quais estão 98% dos 2.906 lixões existentes no país (MMA, 2011). Assim, alguns Estados vêm adotando soluções simplificadas e economicamente viáveis à realidade destes municípios. Destaca-se, no Estado de São Paulo, um programa de governo, que, desde 1999, fomentou a implantação dos denominados Aterros em Valas. Ressalta-se, porém, que estes sistemas simplificados não dispõem de todos os dispositivos de proteção ambiental utilizados em aterros sanitários convencionais, como impermeabilização e sistemas de drenagem de gases e lixiviados. Os principais critérios à utilização destes aterros estão relacionados à escolha de áreas adequadas em relação ao meio físico. Esta simplificação é questionada no meio técnico, principalmente quanto à eventual contaminação ambiental. Assim, esta pesquisa objetivou efetuar a avaliação de aterros sanitários de pequeno porte em valas, quanto ao potencial de alteração da qualidade das águas subterrâneas e do solo. Para tanto, foram selecionados três aterros em valas do Estado de São Paulo, situados nos municípios de Angatuba, Jaci e Luiz Antônio, os quais são considerados adequados, segundo o Inventário Estadual de Resíduos Sólidos (CETESB, 2011). Os resultados indicam que, para as taxas de aplicação de resíduos nessas áreas, variando de 8.000 a 15.000 t/ha, os solos locais têm sido capazes de promover a atenuação natural dos contaminantes. Não foram verificadas alterações significativas na qualidade do solo e das águas subterrâneas, corroborando, até o momento, a adequação da concepção proposta para os aterros sanitários de pequeno porte em valas. Esta tecnologia mostra-se viável como alternativa transitória, considerando-se um processo de melhoria contínua, que visa inicialmente à erradicação dos lixões. Assim, podem ser consideradas boas as perspectivas de se alcançar o objetivo da disposição final ambientalmente adequada dos resíduos sólidos gerados nos municípios de pequeno porte, por meio da utilização desses sistemas / The proper management of solid waste contributes in an unequivocal form with urban sustainability as well as with environmental and human health and well being. The adequate final disposal of solid waste throughout Brazil is recognized as being a problem, especially in the smaller municipalities, which account for 98% of the 2,906 existing waste dumps in the country (MMA, 2011). Therefore, some states are adopting simplified and economically viable solutions for those municipalities. In the State of São Paulo, stands out a government program that has been implemented since 1999, supporting the implantation of so-called landfills in ditches. However, must be pointed out that these simplified systems do not provide all the devices used for environmental protection, as in the conventional landfills, such as adequate liners and drainage systems of gas and leachate. The main criteria for employment of these landfills are related to the appropriate characteristics of the site, mainly with respect to soil type and depth of the groundwater. This simplification is questionable on technical merits, especially regarding possible environmental pollution. Therefore, this study seeks to make an assessment on landfill in ditches, with respect to their potential for altering the quality of both soil and underground water. For this, it was selected three landfill in ditches in the State of São Paulo, located in the municipalities of Angatuba, Jaci and Luiz Antônio, which are considered \"suitable\", according to the State Inventory for Solid Wastes (CETESB, 2011). The results indicate that for the applied loading rates of 8,000 to 15,000 tons per hectare of waste in these areas, the local soil was capable of providing natural attenuation for contaminants. Until now, no significant changes were observed in the soil and groundwater quality, sustaining the proposed concept to small landfills in ditches. The technology shows itself to be viable as a transitional alternative and can be considered as the first step of the continuous improvement processes of waste management and disposal, aimed in short terms the eradication of dumps. Therefore, it was conclude that can be considered good the prospects of achieving the goal of an environmentally acceptable waste disposal, without burdening the small municipalities, within the principles of a required sustainability
462

Estudo da atenuação dos contaminantes de líquidos percolados no solo / Study the pollutants attenuation of the leachate in the soil

Tania Leme de Almeida 23 March 2005 (has links)
A maioria dos municípios brasileiros dispõe os resíduos sólidos domiciliares em locais a céu aberto, sem controle e critério, contribuindo para a poluição das águas superficiais e do lençol freático. Estudos da contaminação de solos e seus mecanismos são cada vez mais explorados devido à necessidade de segurança, a longo prazo, exigida para sistemas de contenção de resíduos. A movimentação de chorume dos aterros para os solos, águas superficiais e subterrâneas coloca em risco a saúde pública pela contaminação. Estudos recentes constataram a existência de processos que permitem a atenuação natural dos contaminantes presentes nestes percolados. O adequado entendimento destes processos pode dar origem a uma série de benefícios possíveis de serem aplicados em aterros antigos, novos ou naqueles que ainda serão concebidos. O presente trabalho avaliou a atenuação de contaminantes, presentes no chorume, pelo solo por meio de experimento desenvolvido em colunas de percolação. O chorume e o solo utilizados neste experimento são provenientes do aterro sanitário de São Carlos - SP. O solo utilizado foi caracterizado quanto à composição físico-química para verificar o transporte do percolado nas colunas e a interação solo-contaminante. As curvas características do transporte de contaminantes traçadas apresentaram baixas concentrações de Pb (Chumbo), Cd (Cádmio), Fe (Ferro), Zn (Zinco) e Mn (Manganês) nas amostras efluentes. Já o Na (Sódio), K (Potássio), Cl (Cloro), Ni (Níquel) e Cu (Cobre) foram preferencialmente lixiviados com o chorume percolante, evidenciando a variação da faixa de concentração de cada elemento no percolado. Os perfis de concentração dos metais pesados mostraram que existe uma frente de contaminação, apresentando uma relação entre a concentração do metal sorvido no solo e sua concentração no percolado. As curvas de retenção de metais no solo mostraram que o Cd, Pb, Cr, Cu e Mn foram preferencialmente sorvidos no solo em relação ao Fe, Zn e Ni. O solo em questão apresentou bom potencial para retenção dos contaminantes presentes no chorume, apesar de ser classificado como arenoso e de suas características químicas não se enquadrarem nos parâmetros adequados para sua utilização em áreas de disposição de resíduos sólidos urbanos. Seu uso em base de aterros sanitários de pequeno porte pode ser considerado, desde que suas características sejam melhoradas por meio da mistura com geossintéticos. Este procedimento acarreta certa economia na construção de camadas impermeabilizantes, pois dispensa o uso de argilas e evita seu transporte de locais distantes do aterro. / The most of brazilian municipal cities disposes solid waste in places at opened sky, without control and criterion, contributing to the pollution of the surface and groundwater. Studies concerning soil contamination and their mechanisms have been explored more and more due to the long term security requirements demanded for residue containment systems. The movement of leachate from the landfill to the soils, surface and groundwaters put on risk the public health because of the contamination. Recent studies verify the existence of processes that allow the attenuation in natural way of the present pollutants in these leachates. The appropriate understanding of these processes propitiates a series of possible benefits of they be applied in old landfill, new or in those that will be implanted. The present work evaluated the attenuation of pollutants, presents in the leachate by the soil through experiment developed in percolation columns. The leachate and soil used in this experiment have came from the sanitary landfill of São Carlos - SP. The collected soil was characterized as to composition physical-chemical to verify the transport of the leachate in the columns and the interaction soil-pollutant. The breakthrough curves traced have been observed that Pb (Lead), Cd (Cadmium), Fe (Iron), Zn (Zinc) and Mn (Manganese) came in low concentration in the effluents leachate. Already the Na (Sodium), K (Potassium), Cl (Chlorine), Ni (Nickel) and Cu (Copper) have been preferably leached with the leachate, showing occurrence of a wide range of concentrations of each species at leachate. Concentration profiles of the heavy metals indicated the existence of a contamination plume, showing relationship between concentration of the metal absorved in the soil and in the leachate. The curves of material´s retention for the soil showed that the Cd, Pb, Cr, Cu and Mn were preferably absorved by the soil in relation to the Fe, Zn and Ni. The soil in subject has presented good potential of retention for the present pollutants in the leachate in spite of being classified as sandy and they chemical characteristics don\'t frame in the appropriate parameters for use in areas of solid waste disposal. Your use in base of sanitary landfill of small load can be considered, since your characteristics have been improved through the mixture of this soil with geo synthetics, involving certain economy at construction of waterproof layers, exempting the clay use and avoid the transport of this material for distant places of the landfill.
463

Infiltração da água em amostras de solo indeformadas e remodeladas em colunas utilizando modelos determinísticos / Infiltration of water in undisturbed and remodeling soil samples in columns using deterministic models

Oliveira, Verena Benício de 11 October 2018 (has links)
Define-se infiltração da água no solo como a entrada da água através da superfície do solo. O processo de infiltração separa, assim, quanto da precipitação pluvial, por exemplo, flui sobre a superfície do solo e quanto flui abaixo da superfície do solo, esta última tanto vertical como horizontalmente. Diversos fatores interferem neste processo, podendo-se destacar aqueles relacionados ao tipo de solo e declividade do terreno e às características do solo e da cobertura vegetal, bem como aquelas relacionadas à precipitação. São conhecidas diversas equações de infiltração, propostas para expressar a lei da infiltração da água em solos, que é o gráfico da taxa de infiltração da água com o tempo. São equações desenvolvidas empiricamente ou a partir de considerações físicas e aplicam-se somente a solos homogêneos e que permanecem homogêneos durante o processo. Dados da literatura têm mostrado que para nossos solos o avanço da frente de molhamento no processo de infiltração vertical também é proporcional à raiz quadrada do tempo, como a solução da equação de Richards obtida por Philip para a infiltração horizontal, porém com uma velocidade maior. Dado este fato, levanta-se a hipótese de utilizar a equação proposta por Philip para a infiltração na direção horizontal também para a direção vertical, em colunas com amostra de solo indeformada e com amostra de solo homogeneamente remodelada. Este trabalho trata do processo da infiltração de água no solo, especificamente a vertical descendente. Pretendeu-se avaliar as equações clássicas da lei da infiltração em amostras homogêneas de três solos estruturalmente distintos com estrutura deformada e indeformada. O experimento foi conduzido em latoratório, em nove colunas com amostras de três solos com características distintas, sendo um Cambissolo Háplico, um Latossolo Vermelho Amarelo distrófico e um Nitossolo Vermelho eutroférrico. As curvas da taxa de infiltração foram determinadas em laboratório e o conteúdo de água foi determinado pela técnica da atenuação gama. A equação proposta por Kostiakov para a lei da infiltração ajustou-se muito bem (máximo R2 para todos os solos, com exceção da coluna indeformada do Nitossolo) por praticamente coincidir com a equação de ajuste estatistico dos dados. Já o mesmo não ocorreu com a equação proposta por Horton para a qual os coeficientes de determinação variaram de 0,528 a 0,898 (sem considerer a amostra do Nitossolo indeformada). Com relação ao modelo de Green & Ampt que, ao contrário das equações de Kostiakov e Horton que são modelos empíricos, pode-se dizer tratar-se de um modelo semi-analítico, os ajustes dos dados também não foram muito bons (R2 variando de 0,802 a 0,898, sem considerer a amostra do Nitossolo indeformada). O modelo quase todo analítico de Philip, baseado na solução da equação de Richards para a direção horizontal, ajustou-se muito bem aos dados desta pesquisa que foi desenvolvida para a direção vertical descendente, visto que o gráfico da posição de frente de molhamento em relação a fonte de água em função da raiz quadrada do tempo de infiltração resultou numa linha reta com alto coeficiente de determinação para todas as amostras (R2 maior que 0,99 para as deformadas e R2 maior que 0,95 para as deformadas). Todos os modelos apresentaram um ajuste ruim (R2 menor que 0,1) para a coluna indeformada do solo 3 (Nitossolo). Provavelmente devido à presença de bioporo no interior da coluna, com fluxo preferencial da água ou também ao processo de amostragem que é muito dificuldato devido a forte estruturação deste solo. / Soil water infiltration is defined as the entry of water through the soil surface. The infiltration process thus separates how much of the rainfall, for example, flows over the soil surface and how much it flows below the surface of the soil, the latter both vertically and horizontally. Several factors interfere in this process, being possible to highlight those related to the type of soil and slope of the terrain and to the characteristics of the soil and vegetation cover, as well as those related to precipitation. Several infiltration equations are known, proposed to express the law of water infiltration in soils, which is the graph of the infiltration rate of water as a function of time. They are equations developed empirically or from physical considerations and apply only to homogeneous soils that remain homogeneous during the process. Literature data have shown that for our soils the advance of the wetting front in the vertical infiltration process is also proportional to the square root of the time, as the solution of the Richards equation obtained by Philip for horizontal infiltration, but with a higher velocity. Given this fact, the hypothesis is proposed to use the equation proposed by Philip for the infiltration in the horizontal direction also for the vertical direction, in columns with undisturbed soil sample and with homogeneously remodeled soil sample. This work deals especifically with the process of vertical descending soil water infiltration. It was intended to evaluate the classical equations of the infiltration law in homogeneous samples of three structurally distinct soils with disturbed and undisturbed structure. The experiment was carried out in a laboratory, in nine columns with three soils distinct characteristics, being a Haplic Cambisol, a Dystrophic Yellow Red Latosol and an eutrophic Red Nitosol. The infiltration rate curves were determined in the laboratory and the water content was determined by the gamma ray attenuation technique. The equation proposed by Kostiakov for the infiltration law adjusted very well (maximum R2 for all soils, except for the undisturbed Nitosol column) since it practically coincide with the equation of statistical fit of the data. The same did not occur with the equation proposed by Horton for which the coefficients of determination ranged from 0,528 to 0.898 (not considering the undisturbed column of Nitosol. In relation to the Green & Ampt model, unlike the Kostiakov and Horton equations that are empirical models, it can be said that it is a semi-analytical model, the data adjustments were also not good changing from 0,802 to 0,848 also not considering the undisturbed Nitosol. Philip\'s almost all-analytical model, based on the solution of the Richards equation for the horizontal direction, fitted very well the data from this work that were conducted in the downward vertical direction, since the graph of the wet facing front position the water source as a function of the square root of the infiltration time resulted in a straight line with a high coefficient of determination for all samples (R2 greater than 0.99 for the deformed and R2 greater than 0.95 for the deformed ones). All models presented a poor fit (R2 less than 0.01) for the undisturbed soil 3 column (Nitosol). Probably due to the presence of biopore inside the column, with preferential flow of water or to the sampling process that is very difficult due to the strong structure of this soil.
464

Metodologia de caracterização da propagação acústica em tubulações de transporte de fluidos bifásicos gás-líquido / Methodology of characterization of acoustic propagation in pipelines for transporting two-phase gas-liquid fluids

Martins, Jaqueline Costa 04 February 2011 (has links)
Este trabalho tem como objetivo global contribuir para o desenvolvimento do estudo da propagação de ondas em dutos de transporte de fluidos, especialmente oleodutos e gasodutos, através da análise da atenuação acústica e da velocidade de propagação da onda. Para isso, foram feitos ensaios experimentais, tanto em escoamento mono quanto bifásico, variando-se a vazão do escoamento em uma linha de testes de 1500 metros e 50 mm de diâmetro, para aquisição de sinais gerados a partir do fechamento de válvulas de simulação de vazamentos em pontos ao longo da tubulação. Para análise da atenuação acústica foi proposta uma metodologia baseada na medição do coeficiente de amortecimento temporal das ondas de pressão como subsídio para o cálculo do coeficiente de atenuação, através da utilização de um único sensor de pressão. Esta metodologia foi validada pela medição direta do coeficiente de atenuação e os resultados mostram uma excelente concordância em escoamentos monofásicos. Para os testes em escoamento bifásico não foi possível aplicar esta metodologia devido ao forte amortecimento das ondas de pressão, sendo feitas apenas medições diretas da atenuação com resultados fenomenologicamente coerentes. A velocidade de propagação acústica para escoamento monofásico foi influenciada pela presença de gás dissolvido e bolhas de cavitação, apresentando valores próximos aos da literatura para baixas vazões de escoamento. Para altas vazões, as velocidades foram compatíveis com o escoamento bifásico a bolhas finamente dispersas. Para o escoamento bifásico o regime de escoamento variou de bolhas a pistonado. As velocidades de propagação obtidas são compatíveis com aquelas obtidas por modelos teóricos. / This work aims to contribute to the development of the study of wave propagation in fluid transport pipelines, through the analysis of acoustic attenuation and propagation speed. For this reason, experimental tests were made in single and two-phase flow, varying the flow rate in a test line of 1500 meters and 50 mm in diameter, for the acquisition of signals generated from the closing of leak simulation valves at known points along the pipeline. To analyze the acoustic attenuation it was proposed a methodology based on measurement of temporal damping coefficient of pressure waves as input for calculating the attenuation coefficient, by using a single pressure sensor. This methodology was validated by direct measurement of attenuation coefficient and the results show an excellent agreement in single-phase flow. For the tests in two-phase flow it was not possible to apply this methodology due to the strong damping of pressure waves, which only made direct measurements of attenuation results phenomenologically consistent. Acoustic propagation velocity for single phase flow was influenced by the presence of dissolved gas and cavitation bubbles, having values close to the literature for low flow rates. For high flows rates, the velocities were consistent with a two-phase flow at finely dispersed bubbles. For the two-phase flow the regime varied from slug to bubbles. The propagation velocities obtained are consistent with those obtained by theoretical models.
465

Nouveaux modèles d'estimation monophone de distance et d'analyse parcimonieuse : Applications sur signaux transitoires et stationnaires bioacoustiques à l’échelle / New models for distance estimation monophone data and sparse analysis : Application to transient signals and stationary signals on large scale bioacoustic data

Doh, Yann 17 December 2014 (has links)
Les ondes acoustiques subissent peu de dispersion dans le milieu marin, comparé au milieu aérien. Certaines espèces de cétacés communiquent ainsi à grande distance, d'autres utilisent leurs émissions sonores pour s'orienter. La bioacoustique consiste à étudier ces espèces à partir de l'analyse de leurs sons, c'est-à-dire à les détecter, classer, localiser. Cela peut se faire via un réseau d'hydrophones au déploiement fastidieux. Afin de contribuer au passage à l'échelle de la bioacoustique, cette thèse propose des modèles originaux mono-hydrophone pour l'analyse de ces signaux stationnaires ou transitoires. Premièrement, nous dérivons un nouveau modèle d'estimation de la distance entre une source impulsive (ex. biosonar) et un hydrophone. Notre modèle théorique, l'Intra Spectral ATténuation(ISAT), dérive des lois acoustiques de déformation spectrale du signal transitoire induite par l'atténuation durant sa propagation. Ce modèle relie les rapports énergétiques des bandes de fréquences pondérés par un modèle de perte par atténuation fréquentielle (Thorp ou Leroy) à la distance de propagation. Nous approximons aussi ISAT par un modèle neuromimétique. Ces deux modèles sont validés sur le sonar du cachalot (Physeter macrocephalus) enregistré avec notre bouée acoustique autonome BOMBYX et notre système d'acquisition DECAV en collaboration avec le Parc National de Port-Cros et le sanctuaire Pelagos pour la protection des mammifères marins en Méditerranée. Les mesures d'erreur (RMSE) d'environ 500 mètres sur nos références du centre d'essai OTAN aux Bahamas présentent un intérêt opérationnel. Deuxièmement, nous proposons une analyse originale de l'évolution des voisements de cétacé par codage parcimonieux. Notre encodage des cepstres par apprentissage non supervisé d'un dictionnaire met en évidence l'évolution temporelle des bigrammes des chants que les baleines à bosse mâles émettent durant la période de reproduction. Nous validons ce modèle sur nos enregistrements du canal de Sainte-Marie à Madagascar entre 2008 et 2014, via notre réseau d'hydrophones BAOBAB qui constitue une première dans l'Océan Indien. Nos modèles s'inscrivent dans le projet Scaled Bioacoustics (SABIOD, MI CNRS) et ouvrent de nouvelles perspectives pour les passages à l'échelle temporelle et spatiale de la bioacoustique. / Acoustic waves show low dispersion due to the underwater propagation, compared to the propagation in the air. Some species of cetaceans communicate at long distance, others use their sound production for orientation. The goal of the scientic area called bioacoustics is to study animal species based on the analysis of their emitted sound. Their sounds can be used to detect, to classify and to locate the cetaceans. Recordings can be done with an passive acoustic array of multiple hydrophones, but this method is expensive and difficult to deploy. Thus, in order to scale this approach, we propose in this Phd thesis several original single hydrophone models to analyze these stationary or transient signals.Firstly, we provide a new theoretical model to estimate the distance between the impulsive source (ex. biosonar of the cetacean) and the hydrophone. Our model, the Intra Spectral ATtenuation (ISAT), is based on the spectral signal alteration due to the underwater acoustic propagation, especially the differences in different frequency bands. We also approximated ISAT by an artificial neural network. Both models are validated on clicks emitted by sperm whales (Physeter macrocephalus) recorded by our sonobuoy BOMBYX and our data-acquisition system DECAV developed incollaboration with the National Park of Port-Cros (France) and the Pelagos sanctuary for the protection of marine mammals in the Mediterranean sea (France). The error (RMSE) measures on the recordings of the NATO test center in the Bahamas are about500 meters, promising further real applications. Secondly, we worked on the variations of the cetacean vocalizations using the sparse coding method. The encoding of thecepstrums by unsupervised learning of a dictionary shows bigrammic time changes of the songs of humpback whales (Megaptera novaeangliae). We validate this model on signals recorded in the Ste Marie Channel (Madagascar) between 2008 and 2014, through our network of hydrophones BAOBAB which is the first passive acoustic array deployed in the Indian Ocean.Our models are part of the Saled Bioacoustics project (SABIOD, MI CNRS) and open perspectives for temporal and spatial scaling of bioacoustics.
466

Avaliação da qualidade das águas subterrâneas e do solo em áreas de disposição final de resíduos sólidos urbanos em municípios de pequeno porte: aterro sanitário em valas / Assessment of the quality of groundwater and soil in areas of final disposal of municipal solid waste in small cities: landfills in ditches

Iwai, Cristiano Kenji 27 March 2012 (has links)
O gerenciamento adequado dos resíduos sólidos contribui de forma inequívoca com a sustentabilidade urbana e com a saúde ambiental e humana. São conhecidas as dificuldades na destinação final adequada dos resíduos sólidos urbanos em todo o Brasil, principalmente em municípios de pequeno porte, nos quais estão 98% dos 2.906 lixões existentes no país (MMA, 2011). Assim, alguns Estados vêm adotando soluções simplificadas e economicamente viáveis à realidade destes municípios. Destaca-se, no Estado de São Paulo, um programa de governo, que, desde 1999, fomentou a implantação dos denominados Aterros em Valas. Ressalta-se, porém, que estes sistemas simplificados não dispõem de todos os dispositivos de proteção ambiental utilizados em aterros sanitários convencionais, como impermeabilização e sistemas de drenagem de gases e lixiviados. Os principais critérios à utilização destes aterros estão relacionados à escolha de áreas adequadas em relação ao meio físico. Esta simplificação é questionada no meio técnico, principalmente quanto à eventual contaminação ambiental. Assim, esta pesquisa objetivou efetuar a avaliação de aterros sanitários de pequeno porte em valas, quanto ao potencial de alteração da qualidade das águas subterrâneas e do solo. Para tanto, foram selecionados três aterros em valas do Estado de São Paulo, situados nos municípios de Angatuba, Jaci e Luiz Antônio, os quais são considerados adequados, segundo o Inventário Estadual de Resíduos Sólidos (CETESB, 2011). Os resultados indicam que, para as taxas de aplicação de resíduos nessas áreas, variando de 8.000 a 15.000 t/ha, os solos locais têm sido capazes de promover a atenuação natural dos contaminantes. Não foram verificadas alterações significativas na qualidade do solo e das águas subterrâneas, corroborando, até o momento, a adequação da concepção proposta para os aterros sanitários de pequeno porte em valas. Esta tecnologia mostra-se viável como alternativa transitória, considerando-se um processo de melhoria contínua, que visa inicialmente à erradicação dos lixões. Assim, podem ser consideradas boas as perspectivas de se alcançar o objetivo da disposição final ambientalmente adequada dos resíduos sólidos gerados nos municípios de pequeno porte, por meio da utilização desses sistemas / The proper management of solid waste contributes in an unequivocal form with urban sustainability as well as with environmental and human health and well being. The adequate final disposal of solid waste throughout Brazil is recognized as being a problem, especially in the smaller municipalities, which account for 98% of the 2,906 existing waste dumps in the country (MMA, 2011). Therefore, some states are adopting simplified and economically viable solutions for those municipalities. In the State of São Paulo, stands out a government program that has been implemented since 1999, supporting the implantation of so-called landfills in ditches. However, must be pointed out that these simplified systems do not provide all the devices used for environmental protection, as in the conventional landfills, such as adequate liners and drainage systems of gas and leachate. The main criteria for employment of these landfills are related to the appropriate characteristics of the site, mainly with respect to soil type and depth of the groundwater. This simplification is questionable on technical merits, especially regarding possible environmental pollution. Therefore, this study seeks to make an assessment on landfill in ditches, with respect to their potential for altering the quality of both soil and underground water. For this, it was selected three landfill in ditches in the State of São Paulo, located in the municipalities of Angatuba, Jaci and Luiz Antônio, which are considered \"suitable\", according to the State Inventory for Solid Wastes (CETESB, 2011). The results indicate that for the applied loading rates of 8,000 to 15,000 tons per hectare of waste in these areas, the local soil was capable of providing natural attenuation for contaminants. Until now, no significant changes were observed in the soil and groundwater quality, sustaining the proposed concept to small landfills in ditches. The technology shows itself to be viable as a transitional alternative and can be considered as the first step of the continuous improvement processes of waste management and disposal, aimed in short terms the eradication of dumps. Therefore, it was conclude that can be considered good the prospects of achieving the goal of an environmentally acceptable waste disposal, without burdening the small municipalities, within the principles of a required sustainability
467

Experimental Analysis of Protective Headgear Used in Defensive Softball Play

Strickland, John Scott 01 January 2019 (has links)
Every year in the United States, an estimated 1.6 to 3.8 million people sustain sports-related traumatic brain injuries (TBIs), with an appreciable number of these injuries coming from the sport of softball. Several studies have analyzed the impact performance of catcher’s masks within the context of baseball; however, virtually no studies have been performed on fielder’s masks within the context of softball. Thus, the main objective of the present work was to evaluate the protective capabilities of softball fielder’s masks. To better understand the injury mechanisms and frequency associated with softball head/facial injuries, epidemiological data from a national database was reviewed first. Results displayed “struck-by-ball” as the most frequent injury mechanism (74.3%) for all head/facial injuries with a large majority occurring to defensive players (83.7%). With further motivation, the present work focused on testing the impact attenuation and facial protection capabilities of fielder’s masks from softball impacts. Testing with an instrumented Hybrid III headform was conducted at two speeds and four impact locations for several protective conditions: six fielder’s masks, one catcher’s mask, and unprotected (no mask). The results showed that most fielder’s masks reduced head accelerations, but not to the standard of catcher’s masks. On average, they reduced peak linear and angular acceleration from 40-mph impacts by 36-49% and 14-45%, respectively, while for 60-mph impacts they were reduced by 25-42% and 13-46%, respectively. Plastic-frame fielder’s masks were observed to allow facial contact when struck at the nose region at high speed. Observed differences in impact attenuation across fielder’s mask designs further suggested influence from specific design features such as foam padding and frame properties. Overall, the results clearly demonstrate that head/facial injuries may be mitigated through the broader use of masks, while further optimization of impact attenuation for fielder’s masks is pursued.
468

Vibration Analysis and Control of Smart Structures

Halim, Dunant January 2003 (has links)
This thesis represents the work that has been done by the author in the area of vibration analysis and control of smart structures during his PhD candidature. The research was concentrated on flexible structures, using piezoelectric materials as actuators and sensors. The thesis consists of four major parts. The first part (Chapter 2) is the modelling of piezoelectric laminate structures using modal analysis and finite element methods. The second part (Chapter 4) involves the model correction of pointwise and spatial models of resonant systems. The model correction solution compensates for the errors associated with the truncation of high frequency modes. The third part (Chapter 5) is the optimal placement methodology for general actuators and sensors. In particular, optimal placement of piezoelectric actuators and sensors over a thin plate are considered and implemented in the laboratory. The last part (Chapters 6 to 8) deals with vibration control of smart structures. Several different approaches for vibration control are considered. Vibration control using resonant, spatial H-2 and H-infinity control is proposed and implemented on real systems experimentally. It is possible, for certain modes, to obtain the very satisfactory result of up to 30 dB vibration reduction. / PhD Doctorate
469

Novel computational methods for image analysis and quantification using position sensitive radiation detectors

Sanchez Crespo, Alejandro January 2005 (has links)
<p>The major advantage of position sensitive radiation detector systems lies in their ability to non invasively map the regional distribution of the emitted radiation in real-time. Three of such detector systems were studied in this thesis, gamma-cameras, positron cameras and CMOS image sensors. A number of physical factors associated to these detectors degrade the qualitative and quantitative properties of the obtained images. These blurring factors could be divided into two groups. The first group consists of the general degrading factors inherent to the physical interaction processes of radiation with matter, such as scatter and attenuation processes which are common to all three detectors The second group consists of specific factors inherent to the particular radiation detection properties of the used detector which have to be separately studied for each detector system. Therefore, the aim of this thesis was devoted to the development of computational methods to enable quantitative molecular imaging in PET, SPET and in vivo patient dosimetry with CMOS image sensors.</p><p>The first task was to develop a novel quantitative dual isotope method for simultaneous assessments of regional lung ventilation and perfusion using a SPET technique. This method included correction routines for photon scattering, non uniform attenuation at two different photon energies (140 and 392 keV) and organ outline. This quantitative method was validated both with phantom experiments and physiological studies on healthy subjects.</p><p>The second task was to develop and clinically apply a quantitative method for tumour to background activity uptake measurements using planar mammo-scintigraphy, with partial volume compensation.</p><p>The third stage was to produce several computational models to assess the spatial resolution limitations in PET from the positron range, the annihilation photon non-collineairy and the photon depth of interaction.</p><p>Finally, a quantitative image processing method for a CMOS image sensor for applications in ion beam therapy dosimetry was developed.</p><p>From the obtained phantom and physiological results it was concluded that the methodologies developed for the simultaneous measurement of the lung ventilation and perfusion and for the quantification of the tumour malignancy grade in breast carcinoma were both accurate. Further, the obtained models for the influence that the positron range in various human tissues, and the photon emission non-collinearity and depth of interaction have on PET image spatial resolution, could be used both to optimise future PET camera designs and spatial resolution recovery algorithms. Finally, it was shown that the proton fluence rate in a proton therapy beam could be monitored and visualised by using a simple and inexpensive CMOS image sensor.</p>
470

Studies on Circulator-Tree Wave Digital Filters

Kumar, Bhunesh, Ahmad, Naeem January 2009 (has links)
<p>A wave digital filter is derived from an analog filter, which is realized as classical doubly resistively terminated reactancefilters. Perfectly designed wave digital filters express good dynamic signal range, low roundoff noise and excellent stabilitycharacteristics with respect to nonlinearity which are produced due to finite wordlength effects. Wave digital filters inheritthe sensitivity properties from analog filters, therefore, coefficients values can be selected to favorable values.Wave digital filters, derived from ladder filters, have low coefficient sensitivity in the passband and stopband. These WDFsare very complicated and are non-modular. The lattice wave digital filters are modular and are not complex. However, theyhave very high sensitivity in the stopband and thus require large coefficient wordlengths. The number of coefficients equalsthe filter order which have to be odd.This thesis discusses the wave digital filter structures that are modular because they are designed by cascading the first-orderand second-order sections. These WDFs can be pipelined. They also exhibit all the above mentioned favorable properties.Similar to lattice WDFs, these structures are restricted to symmetrical and antisymmetrical transfer functions. The synthesisof these structures is based on the factorization of the scattering matrix of lossless two-ports.In this thesis work, lowpass wave digital filters based on circulator-tree structure are designed with different orders startingfrom 3 and going upto 13. In parallel to these circulator-tree wave digital filters, the simple digital filters are also designedwith the same specification. The results of the two filters are compared with each other. It is observed that impulse responseand attenuation response of the two kind of filters perfectly match. Therefore, it is can be concluded that circulator-tree WDFupto Nth order can be synthesized. The implementation examples of two filter with order 3 and order 7 is presented in thisdocumentation for ready reference. It has also been shown that the order of sections does not affect the transfer function ofthe filter. Noise has been introduced and adaptor sections are penetrated. From the results it is concluded that the order of theadaptor sections does not matter and also that the noise does not affect the other adaptors sections, it only propagates throughother adaptors sections.</p>

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