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Afin de caractériser la physico-chimie des matières en suspension de la Moselle et de ses affluents, ce travail s’est appuyé sur une approche géochimique et minéralogique. Notre étude s’est concentrée sur l’analyse des polluants dans les compartiments dissous et particulaire. Ces études ont notamment permis de déterminer (i) la composition des constituants inorganiques dans les particules et colloïdes du milieu aquatique de la Moselle et d’un de ses affluents : la Fensch, (ii) l’évolution des contributions inorganiques le long de la Moselle et de la Fensch ainsi que leur transfert à la confluence Fensch-Moselle, tout en déterminant les sources principales de contamination, (iii) les associations organo-minérales et l’organisation des agrégats présents et (iv) d’étudier la spéciation de certains éléments par des microanalyses. Ce travail a ainsi permis de mettre en évidence l’importance des matières en suspension, souvent négligées par rapport aux autres compartiments Eau et Sédiments / This work uses geochemical and mineralogical approaches to characterize physical and chemical properties of suspended solids in the Moselle and its tributaries. The study focused on analyzing the pollutants in dissolved and particulate compartments. This allowed (i) the identification of inorganic components composition in particles and colloids in the aquatic environment of the Moselle and one of its tributaries: the Fensch, (ii) the determination of the evolution of inorganic contributions along Moselle and the Fensch and their transfer to the confluence Fensch-Moselle in addition to the determination of main contamination sources, (iii) the identification of organo-mineral associations and the determination of the organization of aggregates, (iv) the analysis of the speciation of some elements by microanalysis. This work highlighted the importance of studying suspended solids that are often neglected compared to water and sediments compartments

Three suspended solids types containing a range of physicochemical characteristics were used to determine the effect of suspended solids on the bioavailability of acenaphthene, 1,2,4,5-tetrachlorobenzene, zinc, and chlordane to Daphnia magna and Pimephales promelas. Generally, the bioavailability of zinc and chlordane decreased due to interactions with all suspended solids types while bioavailability of acenaphthene and 1,2,4,5-tetrachlorobenzene were not clearly reduced. Partition coefficients and slope of dose-response curves related chemical characteristics and organism sensitivity, respectively, to experimentally determined results. It is believed that the biologically available form of these chemicals to Daphnia magna and Pimephales promelas resides in the aqueous phase.

Investigating linkages between the compositions of suspended (seston) and benthic particulate matter is important to the understanding of organic matter (OM) cycling and nutrient retention in aquatic systems. We compared the quantity and quality of the truly suspended (TS) and settleable (SB) fractions of seston as well as benthic particulate matter in the tidal freshwater James River, Virginia. The mass of seston and OM was consistently higher in the TS fraction compared to the SB fraction. OM was preferentially retained in the TS fraction relative to seston. The proportional contribution of OM constituents (chlorophyll a, particulate organic carbon and nitrogen) to the two fractions was consistent across observed concentrations whereas increases in seston concentration resulted in decreased proportions in the TS fraction. Benthic constituent reservoirs were large relative to the SB fraction but the higher proportion of OM in the SB fraction suggests that the settleable material was more labile.

Os geotêxteis não-tecidos desempenham, dentre outras funções, papel relevante na filtração e drenagem de solos. Nesta função, necessitam ter vazios suficientemente grandes para permitir a livre passagem de água e, ao mesmo tempo, vazios suficientemente pequenos para impedir o arraste de partículas, de sorte a evitar a erosão interna do solo. Critérios de dimensionamento para atender a ambos os requisitos estão disponíveis na literatura e são utilizados com sucesso há vários anos. Uma situação menos estudada e compreendida refere-se ao desempenho desses geotêxteis na filtração de água com sólidos em suspensão. Trata-se de uma situação tida como crítica, pela possibilidade de colmatação do geotêxtil por essas partículas, de acordo com diferentes mecanismos. Neste trabalho, verifica-se o desempenho, em laboratório, de geotêxteis não-tecidos frente à filtração de suspensões de solo em água, tal qual poderia ocorrer por ocasião de enxurradas. Nessa perspectiva, tenta-se verificar qual poderia ser o desempenho desses geotêxteis quando utilizados para compor sistemas de proteção da entrada de estruturas de captação de água, como bocas de lobo e bueiros. O trabalho utiliza um geotêxtil não tecido de fibras curtas, fabricado a partir de poliéster e suspensões contendo bentonita e uma areia fina argilosa, solo típico da região de São Carlos, em diferentes concentrações. Estabelecem-se correlações entre diferentes características e propriedades dos geotêxteis estudados e estuda-se o mecanismo de colmatação, que em geral ocorreu para todos os geotêxteis, em intervalos de tempo associados às características do geotêxtil e à concentração de solo na suspensão. As severas condições de colmatação observadas e o comprometimento da permeabilidade dos geotêxteis sugerem que para as concentrações de solo utilizadas, os geotêxteis não seriam capazes de cumprir com a proteção da entrada de estruturas de drenagem. / Nonwoven geotextiles play an important role in filtration and drainage of soils, among other functions. In these functions, they need to have large enough internal voids to allow free passage of water and at the same time these voids should be small enough to prevent the passing of particles and preventing piping formation or erosion of soil. Design criteria to satisfy both requirements are available in the literature and have been used successfully for many years. A topic that has not been deeply addressed refers to the performance of geotextiles on filtration of water with suspended solids since the possibility of geotextile clogging is real, impairing its behavior. In this work, the performance of nonwoven geotextiles in laboratory tests designed to observe the filtration of water containing solid particles in suspension is addressed. The tests were devised trying to understand what could be the performance of these geotextiles when used to compose inlet protection systems for drainage structures, such as culverts. The study used nonwoven short-fibers geotextile, made of polyester and suspensions containing bentonite and clayey fine sand, a typical soil of São Carlos area, Brazil, in different concentrations. The laboratory test results show that there exist correlations among different characteristics and properties of geotextiles studied and allowed to evaluate the mechanism of clogging, which generally occurred for all geotextiles, in time intervals associated to some characteristics of the geotextile and to the soil concentration in suspension. The severe clogging observed and the reduction of permeability of geotextile suggest that, for the solids concentration used, the geotextiles could not protect the entrance of drainage structures.

A pesquisa teve como objetivo principal estimar o aporte sedimentar em suspensão na baía da Babitonga a partir de um setor de sua área de contribuição hidrográfica, com base em uma análise geomorfológica da relação entre precipitação, relevo e uso da terra. Adotou-se como referências teórico-metodológicas principais os trabalhos de Ab?Saber, sobre os níveis de tratamento para pesquisas em geomorfologia, e de Tricart, que propõe a classificação dos ambientes segundo seu funcionamento ecodinâmico. Efetuou-se em campo monitoramento mensal das vazões dos dez rios que compõem a área da pesquisa e coletas de amostras de água para quantificação de sedimentos em suspensão em laboratório. Os resultados obtidos indicaram um nítido diferencial no comportamento hidrológico e hidrossedimentológico entre as bacias hidrográficas, que se reflete em distintas parcelas de contribuição de cada bacia no aporte sedimentar em suspensão na baía. Estimou-se que são lançadas na Baía da Babitonga, a partir da área da pesquisa, cerca de 7.624 toneladas/ano de sedimentos em suspensão, estando 77,8% deste volume concentrado na foz do Rio Cubatão. / The research had as main goal to estimate the suspended sediment yield into the Babitonga Bay from a sector of its hydrographic contribution area and was based on a geomorphological approach of the relationship among precipitation, relief and land use. The theorical methodological references were the works from Ab?Saber, about treatment levels for geomorphological research, and from Tricart, which proposes environmental classification based on its ecodynamic behavior. Field monitoring of discharge values was accomplished once a month for all ten rivers of the research área, as well as water sample collecting for laboratory suspended sediment quantification. Results indicate a clear distinct hydrological and hydrossedimentological behavior of the watersheds, which reflect the distinguished suspended sediment yield of each individual watershed into the bay. It was estimated that ca. 7,624 year/tons of suspended sediment are introduced into the Babitonga Bay, with 77.8% of that volume concentrated at the Cubatão river estuary.

Durante as últimas décadas, têm sido realizados vários estudos sobre a aplicação de veículos suspensos como em teleféricos, bondinhos, linhas de transporte e/ou montagem em indústrias, e robôs para finalidades diversas. Como veículos suspensos possuem comportamento de pêndulo, estão suscetíveis as ações de forças externas que geram oscilações e balanços indesejados no veículo que podem comprometer sua função e segurança. Um levantamento bibliográfico mostrou a deficiência de estudos de sistemas que mantenham a estabilidade física de veículos suspensos. Usando conceitos de conservação de energia e quantidade de movimento foi concebida a ideia de desmembrar o corpo do veículo suspenso em duas partes, uma massa fixa e uma massa móvel de atuação e estabilização da estrutura do veículo; dessa forma fazendo uso apenas de componentes internos ao veículo, uma vez que em sistemas suspensos é grande a dificuldade de aplicação de forças externas para correção de posicionamento. Neste trabalho foi desenvolvido um sistema ativo de autoestabilização para veículos suspensos capaz de amenizar os efeitos de forças externas que possam comprometer a atividade desempenhada pelo veículo. Para a autoestabilização foi montado um sistema de controle em malha fechada com sensor de detecção de inclinação (posição) e atuador com motor de corrente contínua para deslocar uma massa móvel dentro do robô suspenso, acionados por um microcontrolador embarcado. A eficiência do sistema foi comprovada com a montagem de um protótipo, onde uma programação baseada em controle proporcional e derivativo foi suficiente para garantir uma eficiente e rápida estabilização no robô quando sujeito a forças externas como atuação de ventos, por exemplo. / During the last decades, many researches and studies have been done about suspended vehicles such as chair lifts, cable cars, carrying and assemblies of parts in the industry, etc. Suspended vehicles behave like a pendulum and they are susceptible to the action of external forces which cause oscillations and unwanted swing at the vehicle that may affect function and security of the vehicle. For several applications it is important to keep the physical stability of suspended vehicles (or part of them), such as in autonomous robots for inspection. In suspended systems it is very difficult to apply external forces to correct its position due the swing; so, it is proposed a new stabilizing system for suspended vehicles based on the conservation of energy and quantity of motion. Using only internal components of the suspended vehicle, the mass of the system was separated in two parts: an active mobile part that stabilizes a fixed part such as the structure of the vehicle. In this work, it is described an active system for swing control on suspended vehicles, able to soften the effects of external forces that can dangerously damage the performance of the vehicle. An autonomous off-board microcontroller with feed-back program was assembled to stabilize the structure of the vehicle by using an inclination sensor attached to it. A DC motor is used to move the mobile part of the suspended vehicle to correct the equilibrium of the vehicles structure. The microcontroller program based on proportional-derivative control system was implemented and tests were performed on a prototype vehicle. A good performance of the system was obtained with an efficient and fast stabilization of the prototype structure under the action of external forces, such as wind forces.

The hydrodynamic behaviour of fine suspended aqueous sediments, and stability of the bedforms they create once settled, are governed by the physical properties (e.g., size, shape, porosity and density) of the flocculated particles in suspension (flocs). Consequently, accurate prediction of the transport and fate of sediments and of the nutrients and pollutants they carry depends on our ability to characterise aqueous flocs. Current research primarily focuses on characterising flocs based on their external gross-scale (>1 μm) properties (e.g., gross morphology, size and settling velocity) using in situ techniques such as photography and videography. Whilst these techniques provide valuable information regarding the outward behaviour of flocculated sediment (i.e. transport and settling), difficulties associated with extracting 3D geometries from 2D projections raises concerns regarding their accuracy and key parameters such as density can only be estimated. In addition, they neglect to inform on the internal micro- and nano-scale structure of flocs, responsible for much of their behaviour and development. Transmission electron microscope (TEM) and environmental electron microscope may be used to obtain nano-scale information in, essentially, 2D but there is a large scale gap between this information and the macro-scale of optical techniques. To address this issue this study uses 3D tomographic imaging over a range of spatial scales. Whilst commonly used in materials science and the life sciences, correlative tomography has yet to be applied in the environmental sciences. Threading together 3D Xray micro-computed tomography (X-ray μCT) and focused ion beam nano-tomography (FIBnt) with 2D TEM makes material characterisation from the centimetre to nanometre-scale possible. Here, this correlative imaging strategy is combined with a non-destructive stabilisation procedure and applied to the investigation of flocculated estuarine sediment, enabling the multi length-scale properties of flocs to be accurately described for the first time. This work has demonstrated that delicate aqueous flocs can be successfully stabilised via a resin embedding process and contrasted for both electron microscopy and X-ray tomography imaging. The 3D information obtained can be correlated across all length-scales from nm to mm revealing new information about the structure and morphology of flocs. A new system of characterising floc structure can be defined based on the association of particles and their stability in the structure rather than simply their size. This new model refutes the postulate that floc structures are fractal in nature.

Vários métodos de amostragem e análise de partículas em suspensão na atmosfera foram discutidos. Os métodos mais utilizados, gravimétrico e refletância foram testados comparativamente e quanto à correlação entre seus resultados em dois locais distintos. Os fatores intervenientes nos resultados obtidos foram estudados quanto à sua influência. Os métodos gravimétrico e reflectância foram analisados quanto a exatidão dos resultados fornecidos e quanto ao seu significado higiênico em função da correlação existente entre concentração de partículas na atmosfera e danos à saúde. A presente investigação levou o autor a concluir por uma significante diferença entre os resultados fornecidos pelos métodos em estudo, por uma correlação estratificada e variável de local para local entre eles, e por inadequacidade dos valores fornecidos por cada um dos métodos em estudo quanto ao fato de não fornecerem os valores de concentração de partículas na atmosfera mais correlacionados com danos à saúde. O autor sugere o uso ou o desenvolvimento de um método que pelo menos separe as partículas nas frações respirável e não respirável e que permita uma análise posterior de cada uma das frações. Sugere ainda que concomitantemente sejam efetuados estudos epidemiológicos de correlação entre os valores obtidos e danos à saúde para determinação de novos padrões de qualidade do ar para partículas em suspensão na atmosfera. / Various methods to evaluate concentrations of suspended particulate matter were discussed. The two most commonly ueed methods, gravimetric high volume sampler and DECD reflectance method were tested to compare and correlate their results in two different places. The interfering factors were studied to deter mine their influence on the results. The hivol and reflectance methods were analysed according to the accuracy of the results and according to the hygienic significance as they correlate with health effects. This investigation brought the author to the conclusion that there is a significant statistical difference between the results of the two methods. There are correlations between the methods, which are stratified and vary from one place to the other. Finally, however the results are not the best estimate of the concentratios of suspended particulate matter that correlates with health effects. The author suggests the use or the development of a new method that at least can separate the particles sampled into two fractions, one respirable and another non-respirable. Both fractions must be collected in such a way and in such quantities that allow for adequate analysis afterwards. It is suggested also, that epidemiological studies to correlate the results with health effects must be carried on et the same time in arder to set new air quality standards for suspended particute matter.

A travers cette thèse, nous avons cherché à développer de nouvelles méthodes de mesure, basées sur la rétrodiffusion acoustique, pour estimer la concentration massique des sédiments en suspension dans les rivières. Souvent, ces sédiments présentent une distribution granulométrique bimodale, i.e. constituée d’un mélange de sédiments fins et de sable. Le principal avantage des méthodes hydroacoustiques est leur capacité à fournir des mesures avec une résolution spatiale et temporelle bien meilleure que les techniques classiques type prélèvement. L’objectif est in fine d’améliorer l’estimation du flux sédimentaire dans les cours d’eau. Des mesures acoustiques multifréquences, associées à des prélèvements physiques, ont été réalisées sur le terrain et dans une cuve expérimentale au laboratoire. Des méthodes d’inversion du signal acoustique ont été testées et développées au laboratoire sur une suspension homogène de sédiments fins. Une nouvelle méthode en particulier, combinant analyse de la rétrodiffusion et de l’atténuation acoustique, a permis de retrouver la concentration massique des sédiments avec une précision de l’ordre de ± 20 %. En rivière, une méthode mixte alliant données de calibration et inversion du signal acoustique à deux fréquences a été développée, permettant, dans certaines conditions, d’estimer la concentration des sédiments fins et du sable sur l’ensemble de la section en travers d’un cours d’eau. Ce résultat confirme la capacité de la technologie hydroacoustique à fournir une information spatiale sur la suspension. Des écarts parfois importants ont été observés entre la réponse acoustique théorique, calculée à partir des données de concentration et de granulométrie, et les mesures acoustiques sur le terrain. Il semble que ces écarts soient dus à la présence d’autres corps diffusants dans les rivières, probablement des flocs et/ou des micro-bulles d’air. Ces travaux appellent au développement d’un cadre théorique plus performant et adapté aux suspensions rencontrées en rivière. / With this PhD, we have tried to develop new measurement methods, based on acoustic backscattering, to estimate the mass concentration of suspended sediments in rivers. These sediments often show a bimodal grain-size distribution, i.e. composed of a mixture of fine and sand particles. The main advantage of hydroacoustic methods is their ability to provide measurements with a much better spatial and temporal resolution than conventional sampling techniques. The ultimate goal is to improve the sediment load estimation in rivers. Multifrequency acoustic measurements, combined with physical sampling, were carried out in the field and in an experimental laboratory tank. Acoustic inversion methods were tested and developed on a homogeneous suspension of fine sediments in the laboratory. A new method was implemented, combining the analysis of acoustic backscatter and attenuation, and led to retrieve the sediment mass concentration with a precision in the order of ± 20%. In rivers, a semi-empirical method combining calibration data and acoustic inversion at two frequencies has been developed, allowing, under certain conditions, to estimate the concentration of fine and sand sediments throughout the entire river cross-section. This result confirms the ability of hydroacoustic technology to provide spatial information on the suspension. Significant differences were frequently observed between the theoretical acoustic response, computed from concentration and particle size data, and the acoustic measurements in rivers. It seems that these differences could be due to the presence of other scatterers in rivers, probably flocs and/or air micro-bubbles. This work calls for the development of a more efficient theoretical framework suitable for river suspensions.