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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

An Analysis of Self-similarity, Momentum Conservation and Energy Transport for an Axisymmetric Turbulent Jet through a Staggered Array of Rigid Emergent Vegetation

Allen, Jon Scott 16 December 2013 (has links)
Marsh vegetation is widely considered to offer protection against coastal storm damage, and vegetated flow has thus become a key area of hydrodynamic research. This study investigates the utility of simulated Spartina alterniora marsh vegetation as storm protection using an ADV measurement technique, and is the first to apply jet self-similarity analysis to characterize the overall mean and turbulent flow properties of a three-dimensional axisymmetric jet through a vegetated array. The mean axial flow of a horizontal axisymmetric turbulent jet is obstructed by three configurations of staggered arrays of vertical rigid plant stems. The entire experiment is repeated over five sufficiently high jet Reynolds number conditions to ensure normalization and subsequent collapse of data by nozzle velocity so that experimental error is obtained. All self-similarity parameters for the unobstructed free jet correspond to typical published values: the axial decay coefficient B is 5:8 +/- 0:2, the Gaussian spreading coefficient c is 85 +/- 5, and the halfwidth spreading rate eta_(1/2) is 0:093 +/- 0:003. Upon the introduction of vegetation, from partially obstructed to fully obstructed, B falls from 5:1+/- 0:2 to 4:2 +/- 0:2 and finally 3:7 +/-0:1 for the fully obstructed case, indicating that vegetation reduces axial jet velocity. Cross-sectionally averaged momentum for the unobstructed free jet is M=M0 = 1:05 +/- 0:07, confirming conservation of momentum. Failure of conservation of momentum is most pronounced in the fully obstructed scenario – M=M0 = 0:54 +/- 0:05. The introduction of vegetation increases spreading of the impinging jet. The entrainment coefficient alpha for the free jet case is 0.0575; in the fully obstructed case, alpha = 0:0631. Mean advection of mean and turbulent kinetic energy demonstrates an expected reduction in turbulence intensity within the vegetated array. In general, turbulent production decreases as axial depth of vegetation increases, though retains the bimodal profile of the free jet case; the fully vegetated case, however, exhibits clear peaks behind plant stems. Turbulent transport was shown to be unaffected by vegetation and appears to be primarily a function of axial distance from the jet nozzle. An analysis of rate of dissipation revealed that not only does the cumulative effect of upstream wakes overall depress the magnitude of spectral energy density across all wavenumbers but also that plant stems dissipate large anisotropic eddies in centerline streamwise jet flow. This study, thus, indicates that sparse emergent vegetation both reduces axial flow velocity and has a dissipative effect on jet flow. Typically, however, storm surge does not exhibit the lateral spreading demonstrated by an axisymmetric jet; therefore, the results of this study cannot conclusively support the claim that coastal vegetation reduces storm surge axial velocity.
12

The Distribution of Coral, Reefs and Coastal Habitats in North Central Cuba

Brady, Aisling 24 February 2009 (has links)
Coral communities have begun to form under small inlet-style bridges along the causeway connecting Cayo Coco to Cayo Guillermo. To understand how these bridge-reefs formed and characterize their attributes relative to surrounding communities, a combination of ecological observations and 13C isotopes were analyzed from the bridges and surrounding reefs, mangrove channels and seagrass patches. Hierarchical Cluster Analysis, Detrended Correspondence Analysis and Canonical Correspondence Analysis were carried out to group which physical attributes contributed to the coral communities in the bridge-reefs and also which habitats they were most similar to, with respect to coral and benthic composition. Bridge reef coral assemblages resembled shallow patch reefs and mangrove channels, while benthic coverage was similar to mangrove channels. Organic matter was from combined seagrass and mangrove sources, with mangrove dominating in some regions more than others. This work demonstrates that habitats within the seascape are inter-related through varying mechanisms and development is multi-dimensional.
13

Crescimento urbano e as alterações ambientais no município de Tramandaí - litoral norte do estado do Rio Grande do Sul : análise geográfica com ênfase nas diferenciações espaciais

Farion, Sônia Rejane Lemos January 2007 (has links)
O presente trabalho refere-se a uma análise das alterações ambientais do município de Tramandaí, localizado no Litoral Norte do Estado do Rio Grande do Sul. A pesquisa procura analisar o município em sua totalidade, de forma integrada, a partir das relações natureza e sociedade, tendo como objetivo principal analisar as alterações ambientais geradas por processos de uso e ocupação do solo decorrente do crescimento urbano no município de Tramandaí, com ênfase no período entre 1991 e 2000. Para tanto, foi necessário um levantamento bibliográfico referente ao meio físico e ao processo de urbanização; análise de dados dos Censos demográficos (1960-2000) e setores censitários de Tramandaí (1991-2000) detalhando os bairros Centro e Agual; análise de fotografias áreas de 1974, e imagem de satélite de 2006, do município de Tramandaí, bem como observações de campo e entrevistas. Verificou-se que o município de Tramandaí se enquadra junto aos municípios urbanos com população permanente, e um significativo número de domicílios ocupados o ano inteiro. Foi constatada que mesmo com as emancipações, esse município apresenta incremento populacional decorrente de sua função polarizadora na região. As principais alterações ambientais identificadas no município de Tramandaí foram: retirada de areia das dunas; construção de prédios em substituição as dunas; aterramento de planície inundável e banhado e ocupação urbana desta área; desmatamento; cultivo de eucalipto; entre outras. Após análise dos setores censitários dos bairros Centro e Agual constatou-se que tanto no próprio bairro, como em comparação com o outro existem diferenciações como: no bairro Centro a baixa ocupação demonstra que a maioria dos domicílios é para 2ª residência, a escolaridade média do chefe de domicílio é ensino médio com a média de 10 salários mínimos, quanto a infra estrutura básica neste bairro predomina o abastecimento de água via rede geral, esgotamento sanitário via rede geral e lixo coletado, e na última década os terrenos com moradias unifamiliares estão sendo vendidos para as construtoras de engenharia civil, sendo substituídas por prédios de luxo, mantendo-se a função de 2ª. residência; enquanto que o bairro Agual passou de 2ª residência para uso permanente entre 1991 e 2000 com maior número de moradores em cada domicílio que no bairro Centro, a escolaridade média do chefe de domicílio é ensino fundamental incompleto, e a média de salários, é quase três salários mínimos, em 2000, em parte deste bairro predomina o abastecimento de água via poço e esgotamento sanitário via fossa rudimentar, tendo alguns domicílios com rede geral e fossa séptica; no restante do bairro a metade recebe o abastecimento de água via rede geral, e cresce o n°. de moradias precárias e o n°. de habitantes no bairro Agual. Constatou-se que em Tramandaí ocorre um crescimento diferenciado, tanto em intensidade quanto no perfil da população com necessidades diferenciadas. / The present work refers to an analysis of the environmental alterations of the municipality of Tramandaí, located in the North Coast of the State of Rio Grande do Sul. The research search to analyze the municipality in her totality, in an integrated way, starting from the relationships nature and society, tends as main objective to analyze the environmental alterations generated by use processes and occupation of the soil due to the urban growth in the municipality of Tramandaí, with emphasis in the period between 1991 and 2000. For so much, it was necessary a bibliographical rising regarding the physical middle and to the urbanization process; analysis of data of the demographic Censuses (1960-2000) and sections censuses of Tramandaí (1991-2000) detailing the neighborhoods Center and Agual; air photograph interpretations the 1974, and satellite of image the 2006, as well as field observations and interviews. It was verified that the municipality of Tramandaí is framed the urban municipality close to with permanent population, and a significant number of occupied homes the whole year. It was verified that even with the emancipations, that municipality presents population increment due to her function to center in the area. The main identified environmental alterations in the municipality of Tramandaí were: retreat of sand of the dunes; construction of buildings in substitution the dunes; landfill of plain flood and swamp and urban occupation of this area; deforestation; eucalyptus cultivation; among others. After analysis of the sections censuses of the neighborhoods Center and Agual it was verified that so much in the own neighborhood, as in comparison with the another differentiations exist as: in the neighborhood Center the low occupation demonstrates that most of the homes is for 2nd residence, the home boss's medium education is medium teaching with the average of 10 minimum wages, as the infra structures basic in this neighborhood the water supply prevails through general net, sanitary exhaustion through general net and collected garbage, and in the last decade the lands with homes are being sold for the builders of civil engineering, being substituted by luxury buildings, staying the function of 2nd. residence; while the neighborhood Agual passed of 2nd residence for permanent use between 1991 and 2000 with larger number of residents in each home that in the neighborhood Center, the home boss's medium education is incomplete fundamental teaching, and the average of wages, it is almost three minimum wages, in 2000, partly of this neighborhood the water supply prevails through well and sanitary exhaustion through rudimentary sewage, tends some homes with general net and septic tank; in the remaining of the neighborhood the half receives the water supply through general net, and it increases the n°. of precarious homes and the n°. of inhabitants in the neighborhood Agual. It was verified that happens a differentiated growth in Tramandaí, in intensity and in the profile of the population with differentiated needs.
14

Crescimento urbano e as alterações ambientais no município de Tramandaí - litoral norte do estado do Rio Grande do Sul : análise geográfica com ênfase nas diferenciações espaciais

Farion, Sônia Rejane Lemos January 2007 (has links)
O presente trabalho refere-se a uma análise das alterações ambientais do município de Tramandaí, localizado no Litoral Norte do Estado do Rio Grande do Sul. A pesquisa procura analisar o município em sua totalidade, de forma integrada, a partir das relações natureza e sociedade, tendo como objetivo principal analisar as alterações ambientais geradas por processos de uso e ocupação do solo decorrente do crescimento urbano no município de Tramandaí, com ênfase no período entre 1991 e 2000. Para tanto, foi necessário um levantamento bibliográfico referente ao meio físico e ao processo de urbanização; análise de dados dos Censos demográficos (1960-2000) e setores censitários de Tramandaí (1991-2000) detalhando os bairros Centro e Agual; análise de fotografias áreas de 1974, e imagem de satélite de 2006, do município de Tramandaí, bem como observações de campo e entrevistas. Verificou-se que o município de Tramandaí se enquadra junto aos municípios urbanos com população permanente, e um significativo número de domicílios ocupados o ano inteiro. Foi constatada que mesmo com as emancipações, esse município apresenta incremento populacional decorrente de sua função polarizadora na região. As principais alterações ambientais identificadas no município de Tramandaí foram: retirada de areia das dunas; construção de prédios em substituição as dunas; aterramento de planície inundável e banhado e ocupação urbana desta área; desmatamento; cultivo de eucalipto; entre outras. Após análise dos setores censitários dos bairros Centro e Agual constatou-se que tanto no próprio bairro, como em comparação com o outro existem diferenciações como: no bairro Centro a baixa ocupação demonstra que a maioria dos domicílios é para 2ª residência, a escolaridade média do chefe de domicílio é ensino médio com a média de 10 salários mínimos, quanto a infra estrutura básica neste bairro predomina o abastecimento de água via rede geral, esgotamento sanitário via rede geral e lixo coletado, e na última década os terrenos com moradias unifamiliares estão sendo vendidos para as construtoras de engenharia civil, sendo substituídas por prédios de luxo, mantendo-se a função de 2ª. residência; enquanto que o bairro Agual passou de 2ª residência para uso permanente entre 1991 e 2000 com maior número de moradores em cada domicílio que no bairro Centro, a escolaridade média do chefe de domicílio é ensino fundamental incompleto, e a média de salários, é quase três salários mínimos, em 2000, em parte deste bairro predomina o abastecimento de água via poço e esgotamento sanitário via fossa rudimentar, tendo alguns domicílios com rede geral e fossa séptica; no restante do bairro a metade recebe o abastecimento de água via rede geral, e cresce o n°. de moradias precárias e o n°. de habitantes no bairro Agual. Constatou-se que em Tramandaí ocorre um crescimento diferenciado, tanto em intensidade quanto no perfil da população com necessidades diferenciadas. / The present work refers to an analysis of the environmental alterations of the municipality of Tramandaí, located in the North Coast of the State of Rio Grande do Sul. The research search to analyze the municipality in her totality, in an integrated way, starting from the relationships nature and society, tends as main objective to analyze the environmental alterations generated by use processes and occupation of the soil due to the urban growth in the municipality of Tramandaí, with emphasis in the period between 1991 and 2000. For so much, it was necessary a bibliographical rising regarding the physical middle and to the urbanization process; analysis of data of the demographic Censuses (1960-2000) and sections censuses of Tramandaí (1991-2000) detailing the neighborhoods Center and Agual; air photograph interpretations the 1974, and satellite of image the 2006, as well as field observations and interviews. It was verified that the municipality of Tramandaí is framed the urban municipality close to with permanent population, and a significant number of occupied homes the whole year. It was verified that even with the emancipations, that municipality presents population increment due to her function to center in the area. The main identified environmental alterations in the municipality of Tramandaí were: retreat of sand of the dunes; construction of buildings in substitution the dunes; landfill of plain flood and swamp and urban occupation of this area; deforestation; eucalyptus cultivation; among others. After analysis of the sections censuses of the neighborhoods Center and Agual it was verified that so much in the own neighborhood, as in comparison with the another differentiations exist as: in the neighborhood Center the low occupation demonstrates that most of the homes is for 2nd residence, the home boss's medium education is medium teaching with the average of 10 minimum wages, as the infra structures basic in this neighborhood the water supply prevails through general net, sanitary exhaustion through general net and collected garbage, and in the last decade the lands with homes are being sold for the builders of civil engineering, being substituted by luxury buildings, staying the function of 2nd. residence; while the neighborhood Agual passed of 2nd residence for permanent use between 1991 and 2000 with larger number of residents in each home that in the neighborhood Center, the home boss's medium education is incomplete fundamental teaching, and the average of wages, it is almost three minimum wages, in 2000, partly of this neighborhood the water supply prevails through well and sanitary exhaustion through rudimentary sewage, tends some homes with general net and septic tank; in the remaining of the neighborhood the half receives the water supply through general net, and it increases the n°. of precarious homes and the n°. of inhabitants in the neighborhood Agual. It was verified that happens a differentiated growth in Tramandaí, in intensity and in the profile of the population with differentiated needs.
15

Crescimento urbano e as alterações ambientais no município de Tramandaí - litoral norte do estado do Rio Grande do Sul : análise geográfica com ênfase nas diferenciações espaciais

Farion, Sônia Rejane Lemos January 2007 (has links)
O presente trabalho refere-se a uma análise das alterações ambientais do município de Tramandaí, localizado no Litoral Norte do Estado do Rio Grande do Sul. A pesquisa procura analisar o município em sua totalidade, de forma integrada, a partir das relações natureza e sociedade, tendo como objetivo principal analisar as alterações ambientais geradas por processos de uso e ocupação do solo decorrente do crescimento urbano no município de Tramandaí, com ênfase no período entre 1991 e 2000. Para tanto, foi necessário um levantamento bibliográfico referente ao meio físico e ao processo de urbanização; análise de dados dos Censos demográficos (1960-2000) e setores censitários de Tramandaí (1991-2000) detalhando os bairros Centro e Agual; análise de fotografias áreas de 1974, e imagem de satélite de 2006, do município de Tramandaí, bem como observações de campo e entrevistas. Verificou-se que o município de Tramandaí se enquadra junto aos municípios urbanos com população permanente, e um significativo número de domicílios ocupados o ano inteiro. Foi constatada que mesmo com as emancipações, esse município apresenta incremento populacional decorrente de sua função polarizadora na região. As principais alterações ambientais identificadas no município de Tramandaí foram: retirada de areia das dunas; construção de prédios em substituição as dunas; aterramento de planície inundável e banhado e ocupação urbana desta área; desmatamento; cultivo de eucalipto; entre outras. Após análise dos setores censitários dos bairros Centro e Agual constatou-se que tanto no próprio bairro, como em comparação com o outro existem diferenciações como: no bairro Centro a baixa ocupação demonstra que a maioria dos domicílios é para 2ª residência, a escolaridade média do chefe de domicílio é ensino médio com a média de 10 salários mínimos, quanto a infra estrutura básica neste bairro predomina o abastecimento de água via rede geral, esgotamento sanitário via rede geral e lixo coletado, e na última década os terrenos com moradias unifamiliares estão sendo vendidos para as construtoras de engenharia civil, sendo substituídas por prédios de luxo, mantendo-se a função de 2ª. residência; enquanto que o bairro Agual passou de 2ª residência para uso permanente entre 1991 e 2000 com maior número de moradores em cada domicílio que no bairro Centro, a escolaridade média do chefe de domicílio é ensino fundamental incompleto, e a média de salários, é quase três salários mínimos, em 2000, em parte deste bairro predomina o abastecimento de água via poço e esgotamento sanitário via fossa rudimentar, tendo alguns domicílios com rede geral e fossa séptica; no restante do bairro a metade recebe o abastecimento de água via rede geral, e cresce o n°. de moradias precárias e o n°. de habitantes no bairro Agual. Constatou-se que em Tramandaí ocorre um crescimento diferenciado, tanto em intensidade quanto no perfil da população com necessidades diferenciadas. / The present work refers to an analysis of the environmental alterations of the municipality of Tramandaí, located in the North Coast of the State of Rio Grande do Sul. The research search to analyze the municipality in her totality, in an integrated way, starting from the relationships nature and society, tends as main objective to analyze the environmental alterations generated by use processes and occupation of the soil due to the urban growth in the municipality of Tramandaí, with emphasis in the period between 1991 and 2000. For so much, it was necessary a bibliographical rising regarding the physical middle and to the urbanization process; analysis of data of the demographic Censuses (1960-2000) and sections censuses of Tramandaí (1991-2000) detailing the neighborhoods Center and Agual; air photograph interpretations the 1974, and satellite of image the 2006, as well as field observations and interviews. It was verified that the municipality of Tramandaí is framed the urban municipality close to with permanent population, and a significant number of occupied homes the whole year. It was verified that even with the emancipations, that municipality presents population increment due to her function to center in the area. The main identified environmental alterations in the municipality of Tramandaí were: retreat of sand of the dunes; construction of buildings in substitution the dunes; landfill of plain flood and swamp and urban occupation of this area; deforestation; eucalyptus cultivation; among others. After analysis of the sections censuses of the neighborhoods Center and Agual it was verified that so much in the own neighborhood, as in comparison with the another differentiations exist as: in the neighborhood Center the low occupation demonstrates that most of the homes is for 2nd residence, the home boss's medium education is medium teaching with the average of 10 minimum wages, as the infra structures basic in this neighborhood the water supply prevails through general net, sanitary exhaustion through general net and collected garbage, and in the last decade the lands with homes are being sold for the builders of civil engineering, being substituted by luxury buildings, staying the function of 2nd. residence; while the neighborhood Agual passed of 2nd residence for permanent use between 1991 and 2000 with larger number of residents in each home that in the neighborhood Center, the home boss's medium education is incomplete fundamental teaching, and the average of wages, it is almost three minimum wages, in 2000, partly of this neighborhood the water supply prevails through well and sanitary exhaustion through rudimentary sewage, tends some homes with general net and septic tank; in the remaining of the neighborhood the half receives the water supply through general net, and it increases the n°. of precarious homes and the n°. of inhabitants in the neighborhood Agual. It was verified that happens a differentiated growth in Tramandaí, in intensity and in the profile of the population with differentiated needs.
16

Floristický průzkum povodí Pozdeňského a Bílichovského potoka na Slánsku / Floristic research in the basin of Pozdeňský and Bilíchovský creeks of Slánsko

BERANOVÁ, Hana January 2008 (has links)
ANNOTATION Hana Beranová University of south Bohemia in České Budějovice {--} Faculty of education {--} department of biology Course: M7504 Teacher for grammar schools Fields of study: Teaching of biology, Teaching of chemistry Floristic research of catchment area of Pozdeň stream and Bílichov stream round Slaný Diploma thesis 2008 The study deals with a description of vegetation of catchment area of Bakov stream and Zlonice stream. In title of study are used the names Pozdeň stream and Bílichov stream, but it{\crq}s only local description. The search had been realised during the vegetation seasons of the years 2006 and 2007. There are characterised geological-petrographical, soil, climatic, hydrographic ratios and basic phytogeographical characteristics of this area in the form of a search. Selected genera of the observed plants are characterised and their incidence is figured in the schematic map of the area. There were found out 299 genera of plants, from which there are 48 stated in the Červený a černý seznam cévnatých rostlin České republiky (stav v roce 2000) (Procházka F. (ed.), 2001). There are described locations of important genera of plants. In discussion of the thesis are described factors, which influence the incidence of some genera of plants. In the annex there are attached schematic maps with places of occurence of the plant genera and photographic documentation. Head of the diploma thesis: Mgr. Rostislav Černý, CSc.
17

Risk assessment for linear alkylbenzene sulfonates in Mediterranean coastal forest exposed to marine aerosols: a physiological perspective

Jalba, Adriana 09 February 2011 (has links)
The aim of this study was to understand the contribution of Linear Alkylbenzene Sulfonates (LAS) to the decline of Mediterranean coastal forest exposed to marine aerosols. LAS are a group of synthetic anionic surfactants widely used in the composition of household or industrial detergents and agrochemicals. This study was part of a large project (RISICO) aiming the assessment of the environmental impact of the LAS at multiple levels: biodegradation in the coastal waters, sorption – desorption processes in the sediments, toxicity to the aquatic life and toxicity to the coastal forest (by aerosolisation of the sea water). <p>Previous studies pointed out this group of surfactants as the main cause of the coastal forest decline. However, the quantification of this surfactant in the environmental samples (mainly sea water and foliar deposition) was done using non-specific analytical methods as methylene blue active substances (MBAS), leading to overestimation of the environmental concentrations of LAS. <p>The work hypothesis was that at actual environmental concentrations, the LAS does not play a key role in the foliar uptake of the sea salt deposited on the coastal vegetation by the marine aerosols, therefore the LAS may not be the main cause of the coastal forest decline. <p>The research involved both greenhouse experiments and field measurements. The experimental work was conducted on young Mediterranean trees (Laurus nobilis L. Quercus ilex L. and Pinus halepensis P. Mill.) and investigated the synergistic toxic effects of exposure to simulated marine aerosol contaminated with surfactants. An array of endpoints was used including photosynthetic activity, relative water content, foliar deposition and uptake of salt and LAS, and pigments analysis. The results of those experiments revealed that LAS itself did not have phytotoxic effects. Nevertheless, the surfactant was shown to enhance the foliar uptake of the salt in the tested species, especially in Pinus halepensis, confirming the conclusions of previous studies regarding the sensitivity of this species to polluted marine aerosols. <p>The field work was conducted in San Rossore National Park (Italy) and Porquerolles Island (France) and was focused on evaluating the health status of the Mediterranean forest (Quercus ilex L. Pinus halepensis Mill. and Pinus pinaster Aiton.) and also on quantification of LAS in coastal aerosols using highly specific analytical methods, like the mass spectrometry (MS). The frequencies and extent of injuries in the coastal trees were found to be correlated to the salt but not with the LAS content of the leaves. The concentrations of LAS in the Pinus and Quercus leaves were comparable in the two studied sites but the concentrations of salt were extremely high in San Rossore, suggesting that other factors may determine the excessive salt foliar uptake. The parallel MS and MBAS carried out in the same set of aerosol samples revealed that MBAS measurements were not relevant for LAS concentrations in the marine aerosols. Projecting the experimental results to the real LAS and salt exposure of the coastal forest, we concluded that LAS may play a marginal role in coastal vegetation decline. <p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

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