• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 104
  • 31
  • 9
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 196
  • 196
  • 51
  • 37
  • 32
  • 29
  • 25
  • 24
  • 24
  • 21
  • 20
  • 19
  • 19
  • 18
  • 16
  • 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.
141

Estrógenos em águas estuarinas: estudo analítico e ambiental para o estuário Santos-São Vicente / Estrogens in estuarine waters: analytical and environmental study for Santos-São Vicente estuary

Gonçalves, Renato Miani [UNESP] 22 July 2016 (has links)
Submitted by Renato Miani Goncalves null (renatomiani@gmail.com) on 2016-08-05T18:39:41Z No. of bitstreams: 1 Tese - Renato Goncalves.pdf: 4535061 bytes, checksum: ea8e64f761cc44656f8a8018ef7c2d85 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-08-10T16:44:41Z (GMT) No. of bitstreams: 1 goncalves_rm_dr_araiq.pdf: 4535061 bytes, checksum: ea8e64f761cc44656f8a8018ef7c2d85 (MD5) / Made available in DSpace on 2016-08-10T16:44:41Z (GMT). No. of bitstreams: 1 goncalves_rm_dr_araiq.pdf: 4535061 bytes, checksum: ea8e64f761cc44656f8a8018ef7c2d85 (MD5) Previous issue date: 2016-07-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O sudeste brasileiro é a região mais populosa do país, estando nele o estuário de Santos-São Vicente, com aproximadamente 1,5 milhões de habitantes. Localizado nesse complexo estuarino, está o Porto marítimo mais movimentado da América Latina e um dos mais importantes pólos petroquímicos do país. Nessa região o tratamento de esgoto sanitário é praticamente inexistente (cobrindo aproximadamente 20% de toda população), não havendo estudos sobre a ocorrência ambiental e a dinâmica de estrógenos ou outros alteradores endócrinos no local. Por outro lado, frequentemente os estudos ambientais existentes sobre a ocorrência de contaminantes, negligenciam a confiabilidade analítica. Frente à esse cenário, o presente estudo apresenta a determinação de estrógenos (17α–etinilestradiol (EE2), 17β-estradiol (E2) e estriol (E3)) em água do mar com alta confiabilidade, utilizando método baseado em extração em fase sólida (SPE) e análise por HPLC-FLD, com o uso de ferramentas estatísticas para a modelagem da curva analítica, avaliação do efeito matriz e estudo de conservação dos cartuchos SPE após a eluição da amostra. O processo de validação analítica mostrou valores adequados de recuperação (76-94%, para diferentes concentrações de EE2, E2 e E3), precisão (coeficiente de variação menor que 20%) e seletividade. Os limites de deteção do método para o EE2, E2 e E3 foram respectivamente de 9,7, 2,3 e 4,3 ng L-1. Cinco curvas analíticas para cada composto foram utilizadas para avaliar o efeito matriz, sendo as soluções padrões preparadas em solvente (acetonitrila), água marinha artificial (S=30) e agua marinha, sendo para essas últimas, os padrões adicionados hora antes da extração, hora após a eluição da amostra no cartucho. Para o preparo de cada curva analítica foram utilizados seis concentrações diferentes dos padrões, sendo as curvas analíticas refeitas para cada amostragem realizada. O modelo teve por base a regressão linear, utilizando ajuste por mínimos quadrados, sendo o mesmo avaliado por análise de variância (ANOVA). Os resultados mostraram efeito matriz para todos os analitos. A conservação dos analitos nos cartuchos SPE foram avaliados para 6; 22; 29; 55 e 80 dias, e os resultados evidenciaram que não houve diferença significativa entre eles. Foram realizadas três amostragens no estuário de Santos-São Vicente, em março de 2014 (12 pontos amostrais de superfície), e fevereiro e junho de 2015 (com 15 pontos amostrais de superfície e 6 pontos amostrais de águas de fundo, na baía de Santos). Os valores de concentração para o estriol (mais frequentemente encontrado) variaram entre ND-354 ng L-1, para o 17β-estradiol de nd-18 ng L-1 enquanto o 17α–etinilestradiol não foi quantificado em nenhuma das amostras. Não foram observadas diferenças entre as amostragens nas diferentes estações do ano, sendo as maiores variações de concentrações observadas no âmbito de diferentes comportamentos de maré (sizígia e quadratura). No geral, os valores de concentrações encontrados para o estriol e estradiol podem acarretar riscos aos organismos aquáticos quando os mesmos são expostos à esses alteradores por longos períodos. / Southeast is the Brazilian most populated region. Santos-São Vicente estuary, located there, includes c.a. 1.5 million inhabitants, one of the most important Brazilian petrochemical sites and the bigger harbor from Latin America. In this region, the sewage treatment is almost inexistent (covers c.a. 20% of all population), nevertheless there are not studies about the occurrence and environmental dynamics of estrogens or others endocrine disruptors there. On the other hand, the analytical reliability in environmental studies have been frequently neglected. Thus, this work presents a reliability evaluation for estrogens (EE2, E2 and E3) determination in marine water, using a method based in solid phase extraction (SPE) and HPLC-FLD analysis, statistical tools were used to accomplish the calibration curve, storage time of SPE cartridges after sample elution and matrix effects. The analytical validation process showed adequate selectivity, recovery (76-94%, for different concentrations of EE2, E2 and E3) and precision (RSD below 20%). The method detection limit for EE2, E2 and E3 was 10, 2 and 4 ng L-1, respectively. Five analytical curves for each compound were used to evaluate the matrix effect wherein the standard solutions were prepared in solvent (acetonitrile, or on the SPE extract from artificial seawater (S=30) or in natural seawater). Additionally, for artificial and natural seawater, the standards were spiked to matrix before the SPE. All standard solution contained all the studied estrogens, at the same concentration, for each curve it was used six standards concentrations. Model fitting was done by linear regression models, using ANOVA to evaluate the fittings. The results showed matrix effects for all analytes, thus matrix-matched (natural seawater) analytical curves were used at the following method validation steps. SPE cartridges storage time (after sample loading) was studied for 6, 22, 29, 55 and 80 storage days, data demonstrated no significant differences for these storage times. Three sampling was made at Santos estuary, in march 2014, february 2015 and june 2015, with 15 samples collected each. Estriol (E3) concentrations ranging ND-354 ng L-1, estradiol (E2) ND-18 ng L-1 while 17α–ethynylestradiol (EE2) were not detectable in any samples (below method LOQ). Overall, estriol concentration are above no-observed-effect concentrations from long-term exposition, which can lead to risk for aquatic organisms.
142

Análise das condições ambientais e da dispersão de plumas de efluentes na região costeira centro-sul do Estado de São Paulo com uso da modelagem numérica / Analysis of environmental conditions and the dispersion of effluent plumes in the south-central coastal region of São Paulo State using numerical modeling

Samuel Hora Yang 30 September 2016 (has links)
A região de estudo está localizada no litoral centro do Estado de São Paulo, engloba a área de proteção ambiental do Parque Estadual Marinho da Laje de Santos, e sofre a influência de três emissários submarinos e de lançamentos de esgotos pelo Rio Itanhaém. O objetivo deste trabalho foi o de analisar as condições ambientais e a dispersão das plumas de efluentes emitidas pelos emissários submarinos de Praia Grande e do Rio Itanhaém, quanto à concentração de potenciais poluentes, por meio de modelagem numérica. Objetivos secundários compreendem o interesse no conhecimento das variabilidades espaço-temporais da hidrodinâmica costeira e dos processos de dispersão das plumas de efluentes, através de simulações numéricas, incluindo a avaliação dos resultados de concentrações de indicadores de qualidade da água diante dos níveis máximos estabelecidos pelas Resoluções N.º 274/2000 e N.º 357/2005 do Conselho Nacional do Meio Ambiente. Para tanto, foram utilizados os módulos hidrodinâmico e de qualidade da água do modelo Delft3D, bem como o modelo Visual Plumes. Os resultados das simulações hidrodinâmicas foram concordantes com as feições hidrodinâmicas estabelecidas na literatura e foram validados com alto grau de confiabilidade. A modelagem de campo próximo mostrou a influência das correntes de maré e das correntes geradas pelo vento no transporte e na diluição inicial das plumas de efluentes dos emissários submarinos, onde o transporte por correntes geradas pelo vento permitiu uma diluição mais eficiente. Os resultados da modelagem de campo distante das plumas dos emissários submarinos e do Rio Itanhaém indicaram que estas plumas não afetam a qualidade da água do Parque Estadual Marinho da Laje de Santos; e que a concentração dos indicadores de qualidade da água selecionados (Escherichia coli, amônio, nitrato e fosfato) não ultrapassa os limites máximos estabelecidos pelo Conselho Nacional do Meio Ambiente ao atingir o litoral. Uma vez que a literatura aponta que as praias locais são frequentemente classificadas com balneabilidade imprópria e com má qualidade da água, os córregos que despejam esgoto bruto e não tratado diretamente nas praias podem ser apontados como os responsáveis pela contaminação ambiental do litoral da região de estudo. O modelo de qualidade da água foi validado, apesar de algumas diferenças nas comparações entre seus resultados e amostragens in situ. Foi observado que a região de estudo necessita de mais investimentos em saneamento básico e maior conscientização da população para combater a poluição ambiental local, especialmente o despejo de esgotos em córregos e praias. / The study region is located in the central coast of São Paulo, encompasses the area of environmental protection of Laje de Santos Marine State Park, and is influenced by three outfalls and sewage releases by Itanhaém River. The objective of this study was to analyze the environmental conditions and the dispersion of effluent plumes emitted by Praia Grandes submarine outfalls and Itanhaém River, concerning the concentration of potential pollutants, through numerical modeling. Secondary objectives are related to interest in the knowledge of the spatial-temporal variability of coastal hydrodynamics and processes of effluent plumes dispersion, through numerical simulations, including the evaluation of water quality indicators concentrations results as compared to the maximum levels established by the National Environmental Council Resolutions N.º 274/2000 and N.º 357/2005. For that, Delft3D models hydrodynamic and water quality modules were used, as well as the Visual Plumes model. Results of hydrodynamic simulations were consistent with the hydrodynamics features established in the literature and have been validated with a high degree of reliability. The near-field modeling showed the influence of tidal currents and wind-driven currents in the transport and initial dilution of effluent plumes from the submarine outfalls, where transport by wind-driven currents allowed a more efficient dilution. The far-field modeling results of the plumes from the submarine outfalls and Itanhaém River showed that those plumes dont affect the water quality of Laje de Santos Marine State Park; and the selected water quality indicators concentrations (Escherichia coli, ammonium, nitrate and phosphate) do not exceed the maximum levels established by the National Environmental Council when reaching the shore. Once the literature indicates that the local beaches are often classified as inappropriate for bathing and with bad water quality, streams that dump raw and untreated sewage directly on the beaches can be identified as the responsible for the environmental contamination of the study areas shore. The water quality model was validated, despite some differences in the comparisons between its results and in situ sampling. It was observed that the study area needs more investments in basic sanitation and greater awareness of the population to tackle local environmental pollution, especially the dumping of sewage into streams and beaches.
143

Some aspects of mercury accumulation by the purple shore crab Hemigrapsus nudus Dana (Crustacea: decapoda)

Swanson, Ralph Gene 01 January 1973 (has links)
The present study has attempted to investigate some of the more basic questions concerning the toxicity and accumulation of mercury in the purple shore crab, Hemigrapsus nudus. This rocky intertidal denizen is found in abundance along the entire Pacific coast of the United States from Sitka, Alaska, to the Gulf of California where it dominates the mid-tide pool region. Local specimens were collected just north of the Pacific Marine Stations, Dillon Beach, Marin County, California. The animal is hearty and can be kept in a state of good health for long periods of time in the laboratory with minimum care and negligible mortality. Most importantly, as a middle intertidal inhabitant, H. nudus would be among the first groups of organisms to feel the stress of environmental contamination from an industrial source located on the open coast. This, coupled with its wide distribution, indicates its possible use as an environmental monitor.
144

Anthropogenic influence on the sedimentary regime of an urban estuary - Boston Harbor

Fitzgerald, Michael Gerard January 1980 (has links)
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1980. / Microfiche copy available in Archives and Science. / Vita. / Bibliography: leaves 234-241. / by Michael G. Fitzgerald. / Ph.D.
145

Advancing the theory and applications of Lagrangian Coherent Structures methods for oceanic surface flows / Advancing the theory and applications of LCS methods for oceanic surface flows

Filippi, Margaux(Martin-Filippi) January 2019 (has links)
Thesis: Sc. D., Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2019 / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 207-218). / Ocean surface transport is at the core of many environmental disasters, including the spread of marine plastic pollution, the Deepwater Horizon oil spill and the Fukushima nuclear contamination. Understanding and predicting flow transport, however, remains a scientific challenge, because it operates on multiple length- and time-scales that are set by the underlying dynamics. Building on the recent emergence of Lagrangian methods, this thesis investigates the present-day abilities to describe and understand the organization of flow transport at the ocean surface, including the abilities to detect the underlying key structures, the regions of stirring and regions of coherence within the flow. Over the past four years, the field of dynamical system theory has adapted several algorithms from unsupervised machine learning for the detection of Lagrangian Coherent Structures (LCS). The robustness and applicability of these tools is yet to be proven, especially for geophysical flows. / An updated, parameter-free spectral clustering approach is developed and a noise-based cluster coherence metric is proposed to evaluate the resulting clusters. The method is tested against benchmarks flows of dynamical system theory: the quasi-periodic Bickley jet, the Duffing oscillator and a modified, asymmetric Duffing oscillator. The applicability of this newly developed spectral clustering method, along with several common LCS approaches, such as the Finite-Time Lyapunov Exponent, is tested in several field studies. The focus is on the ability to predict these LCS in submesoscale ocean surface flows, given all the uncertainties of the modeled and observed velocity fields, as well as the sparsity of Lagrangian data. This includes the design and execution of field experiments targeting LCS from predictive models and their subsequent Lagrangian analysis. / These experiments took place in Scott Reef, an atoll system in Western Australia, and off the coast of Martha's Vineyard, Massachusetts, two case studies with tidally-driven channel flows. The FTLE and spectral clustering analyses were particularly helpful in describing key transient flow features and how they were impacted by tidal forcing and vertical velocities. This could not have been identified from the Eulerian perspective, showing the utility of the Lagrangian approach in understanding the organization of transport. / by Margaux Filippi. / Sc. D. / Sc.D. Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution)
146

Analysis and prediction of beach water quality in Hong Kong: with special reference to Big Wave BayBeach

Wong, Ho-chuen., 黃浩川. January 2009 (has links)
published_or_final_version / Civil Engineering / Master / Master of Philosophy
147

A comparative study of liability arising from the carriage of dangerous goods between Chinese and English Law

Lu, Chang January 2009 (has links)
This thesis is about the rights and liabilities arising under English and Chinese law in respect of the carriage of dangerous cargo. It is noted that the danger in dangerous cargoes was not necessarily something in the goods themselves, but might well lie in the way they were packaged, looked after or transported. Accordingly, the responsibilities and liabilities of the various parties with regards to the carriage of dangerous cargoes are usually intertwined and complex. The purpose of this thesis is to analyse and evaluate the dangerous cargoes liabilities in English and Chinese law, by providing suggestions for existing problems in each country based on three sources: contract, tort and statute. Moreover, the chain of causation and concept of remoteness has particular importance in order to establish liability and decide which type and what amount of damage is recoverable. This thesis compares both countries’ liability regimes and how to secure compensation for its victims, and the restoration of the environment, with reference to the EU Environmental Liability Directive and relevant international conventions. The author draws her final conclusions from four important issues: (1) the meaning of dangerous cargo, the packing and handling; (2) the scheme of liability; (3) the channelling of liability; and (4) the type of recoverable damage.
148

TRANSPORT MARITIME DE PRODUITS CHIMIQUES LIQUIDES ET FLOTTANTS : ETUDE EXPERIMENTALE DU REJET ACCIDENTEL SOUS-MARIN SUITE A UN NAUFRAGE / MARITIME TRANSPORT OF LIQUID AND FLOATING CHEMICALS : EXPERIMENTAL STUDY OF THE SUBMARINE ACCIDENTAL RELEASE FOLLOWING A SHIPWRECK

Fuhrer, Mélanie 18 December 2012 (has links)
Le transport par voie maritime s’est développé très rapidement durant la dernière décennie. Il constitue la solution idéale pour déplacer à faibles coûts d’importantes quantités de marchandises sur de longues distances. L’accroissement de ces échanges entraine inévitablement une augmentation de la fréquentation des routes maritimes, de la densité du trafic et donc du risque d’accident et de naufrage.Les quantités impliquées lors d’un accident étant importantes, un rejet sous-marin de produit chimique issu d’une épave peut provoquer de graves conséquences environnementales et humaines. Or, les mécanismes physico-chimiques apparaissant lors du transfert du produit à la surface sont encore mal compris. Ces mécanismes dépendent de nombreux paramètres dont les propriétés physico-chimiques intrinsèques au produit et celles propres à l’environnement de l’accident.Ce travail de recherche, réalisé en collaboration entre l’Ecole des Mines d’Alès et le Cedre, s’inscrit dans l’amélioration de la compréhension du comportement d’un rejet de produit chimique liquide, flottant et soluble issu d’une épave. Cette étude expérimentale a été réalisée selon 3 points :- La phénoménologie du rejet à la brèche dont l’objectif est de quantifier le débit et les modes de rejet,- Le comportement hydrodynamique du produit libéré et son évolution lors de la remontée dans la colonne d’eau,- Le transfert de matière du produit lors de sa solubilisation dans la colonne d’eau.Pour chaque point, les résultats obtenus sont comparés à ceux prédits par les corrélations disponibles dans la littérature afin de proposer une modélisation globale des conséquences adaptée à la gestion des pollutions marines. / Maritime transport quickly increases during the last decade. It is the cheapest way to transport large quantities of goods over long distances. The growth of this trade necessarily leads to an increase in the traffic density and therefore the risk of accident and sinking increases as well.The large amount of chemicals involved in an accident may threaten the environment and human health in case of shipwreck with underwater chemical release. Unfortunately the physicochemical mechanisms occurring during the transfer of a chemical to the sea surface are still poorly understood. Those mechanisms depend on various parameters such as the physicochemical properties of the chemicals and the specific properties of the accident surroundings. This research was conducted in collaboration with the Ecole des Mines d'Alès and Cedre in a global approach to understand the behaviour of liquid, floating and soluble chemicals released after a shipwreck. This experimental study has been carried out according to 3 main points:- The phenomenology of a release at the breach. The objectives are to quantify the flow rate and the release pattern,- The hydrodynamic behaviour of the released chemicals and their fate in the water column,- The mass transfer of the chemical during its solubilization in the water column.For each point, the results are compared to those predicted by correlations in the literature in order to propose a global model of consequences that is adapted to the marine pollution management.
149

Análise de política pública sobre lixo marinho em diferentes níveis governamentais / Marine Debris Public Policies Analysis on Diferents Governamental Levels

Oliveira, Andréa de Lima 19 April 2013 (has links)
Os resíduos sólidos são um dos principais poluentes do ambiente marinho, responsáveis por prejuízos ecológicos, econômicos e na saúde pública, requerendo ações e políticas públicas para seu controle. Em âmbito internacional, muitas convenções abordaram o tema, incentivando os governos a adotarem medidas para conter suas fontes. O Brasil possui um conjunto de instrumentos com diretrizes para a gestão dos resíduos sólidos, mas será que esses instrumentos - leis, programas, planos, investimentos e indicadores - são adequados para reduzir o lixo marinho? Utilizando o Brasil, o estado de São Paulo, o litoral norte paulista e seus municípios como estudos de caso, foram analisadas as políticas públicas relacionadas ao tema, por meio do levantamento da legislação e a análise dos programas governamentais (planos plurianuais) e seus indicadores. A hipótese proposta era de que os instrumentos existentes são inadequados para reduzir o lixo marinho em todos os níveis governamentais. No entanto, as conclusões indicaram que os instrumentos disponíveis são parcialmente adequados, pois embora não haja um enfoque específico no problema do lixo marinho, o combate a ele pode ser identificado indiretamente nas políticas existentes. O principal problema, entretanto, está na implementação das políticas com baixo investimento, pontuais no tempo e geograficamente, e com indicadores inadequados. / Solid wastes are one of the main marine environment pollutants, responsible for ecological, economic and public health damages. Thus, requiring specific actions and public policies to control their entrance in the environment. On the international level, many conventions deal with this issue, encouraging the governments to adopt measures to reduce its sources. Brazil has a set of legal instruments with the guidelines to solid waste management. Nevertheless, are these instruments - laws, programs, plans, investments and indicators - suitable to reducing marine debris? Using Brazil, São Paulo State, North Coast of São Paulo and their municipalities as case studies, the policies related to the issue were analyzed, through a survey of existing laws, as well as analyzing the government programs (multiannual plans) and their indicators. The initial hypothesis was that the existing instruments were inadequate to reduce marine debris in every governmental level. However, the conclusions suggested that the available instruments were partially suitable, for though there is not a specific focus on marine debris issue, the struggle against it can be identified indirectly on the existing policies. The main problem, however, relates to policies implementation with low funds, punctual in time and geographically, and with inappropriate indicators.
150

The Ascidian Styela plicata As a Potential Bioremediator of the Brown Tide Pelagophytes Aureoumbra lagunensis and Aureococcus anophagefferens

Unknown Date (has links)
A brown tide bloom of the pelagophyte Aureoumbra lagunensis caused significant impacts to north Indian River Lagoon (IRL) in 2012-2013, including seagrass die-offs, fish kills, and reduced growth and grazing of ecologically important bivalves. There is potential for another pelagophyte, Aureococcus anophagefferens, to expand into this system. Filtration rates (FR) of the pleated tunicate Styela plicata exposed to Aureoumbra lagunensis and Aureococcus anophagefferens were measured against exposure to a control alga (Tisochrysis lutea) in order to determine its potential use as a bioremediator against these harmful algal blooms (HABs). In addition, whether S. plicata might serve as a vector of HABs was studied by culturing fecal deposits. Short-term exposure to HABs significantly reduced FR, whereas long-term exposure indicates comparable cell removal compared to the control. Vector potential of S. plicata was inconclusive. Results warrant further research to determine whether S. plicata can acclimate or respond to HAB conditions over time. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

Page generated in 0.0762 seconds