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An application of asymmetrical glass fibre-reinforced plastics for the manufacture of curved fibre reinforced concreteFunke, Henrik, Gelbrich, Sandra, Ulke-Winter, Lars, Kroll, Lothar, Petzoldt, Carolin 28 August 2015 (has links)
There was developed a novel technological and constructive approach for the low-cost production of curved freeform formworks, which allow the production of single and double-curved fibre reinforced concrete. The scheduled approach was based on a flexible, asymmetrical multi-layered formwork system, which consists of glass-fibre reinforced plastic (GFRP). By using of the unusual anisotropic structural behavior, these GFRP formwork elements permitted a specific adjustment of defined curvature. The system design of the developed GFRP formwork was examined exhaustively. There were designed, numerically computed and produced prototypical curved freeform surfaces with different curvature radii.
The fibre reinforced concrete had a compressive strength of 101.4 MPa and a 3-point bending tensile strength of 17.41 MPa. Beyond that, it was ensured that the TRC had a high durability, which has been shown by the capillary suction of de-icing solution and freeze thaw test with a total amount of scaled material of 874 g/m² and a relative dynamic E-Modulus of 100% after 28 freeze-thaw cycles.
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WALL-DIAPHRAGM OUT-OF-PLANE COUPLING INFLUENCE ON THE SEISMIC RESPONSE OF REINFORCED MASONRY BUILDINGSAshour, Ahmed January 2016 (has links)
Recent research interests in studying the performance of different seismic force resisting systems (SFRS) have been shifting from component- (individual walls) to system-level (complete building) studies. Although there is wealth of knowledge on component-level performance of reinforced masonry shear walls (RMSW) under seismic loading, a gap still exists in understanding the response of these components within a complete system. Consequently, this study’s main objective is to investigate the influence of the diaphragm’s out-of-plane stiffness on the seismic response of RMSW buildings. In addition, the study aims to synthesize how this influence can be implemented in different seismic design approaches and assessment frameworks. To meet these objectives a two-story scaled asymmetrical RMSW building was tested under quasi-static cyclic loading. The analysis of the test results showed that the floor diaphragms’ out-of-plane stiffness played an important role in flexurally coupling the RMSW aligned along the loading direction with those walls orthogonal to it. This system-level aspect affected not only the different wall strength and displacement demands but also the failure mechanism sequence and the building twist response. The results of the study also showed that neglecting diaphragm flexural coupling influence on the RMSW at the system-level may result in unconservative designs and possibly undesirable failure modes. To address these findings, an analytical model was developed that can account for the aforementioned influences, in which, simplified load-displacement relationships were developed to predict RMSW component- and system-level responses under lateral seismic loads. This model is expected to give better predictions of the system response which can be implemented, within the model limitations, in forced- and displacement-based seismic design approaches. In addition, and in order to adapt to the increasing interest in more resilient buildings, this study presents an approach to calculate the system robustness based on the experimental data. Finally, literature shows that the vast majority of the loss models available for RMSW systems were based on individual component testing and/or engineering judgment. Consequently, this study proposes system damage states in lieu of component damage states in order to enhance the prediction capabilities of such models. The current dissertation highlights the significant influence of the diaphragm out-of-plane stiffness on the system-level response that may alter the RMSW response to seismic events; an issue that need to be addressed in design codes and standards. / Dissertation / Doctor of Philosophy (PhD)
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The Rationality of Nonconformity: the United States decision to refuse ratification of Protocol I Additional to the Geneva Conventions of 1949Childers, Rex A. 08 August 2008 (has links)
No description available.
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Field Oriented Current Control with Harmonic Injection in a Six-Phase Induction MachineShan, Xinyue January 2021 (has links)
As a new type of machine, the multi-phase machine has the advantages ofhigher power rating, higher fault tolerance capability and more degrees offreedom to control compared with the traditional machine. Aiming at runninga multi-phase machine with different phase-pole configurations smoothly,a new method called harmonic plane decomposition is presented. Thisproject focuses on applying harmonic plane decomposition to the modellingand analysis of a six-phase machine. The parameters of the machine wereidentified in both the first and fifth harmonic planes. The machine modelusing harmonic plane decomposition method is built in Matlab/Simulink. Asimulation based on the indirect rotor field oriented control of the machine isthen performed. The simulation result shows that the machine could switchbetween different phase-pole configurations without causing too much speedripple. Debugging and testing a prototype control board is conducted. Thecontrol strategy of the machine is tested on the testbench. The machine couldoperate as a six-phase machine successfully. / Som en ny typ har flerfasmaskinen fördelarna, inklusive högre effekt, högrefeltolerans och fler frihetsgrader att styra jämfört med den traditionella maskinen.Med sikte på att köra en flerfasmaskin med olika faspolskonfigurationersmidigt presenteras en ny metod som kallas harmonisk plan sönderdelning.Detta projekt fokuserar på att tillämpa harmonisk plan sönderdelning på modelleringoch analys av en sexfasmaskin. Maskinens parametrar identifieradesi både det första och det femte harmoniska planet. Maskinmodellen medharmonisk plan sönderdelning är byggd i Matlab/Simulink. En simuleringbaserad på den indirekta rotorfältorienterade styrningen av maskinen utförssedan, och resultatet visar att maskinen kan växla mellan olika faspolskonfigurationerutan att orsaka oacceptabel hastighetsrippling. Felsökning ochtestning av en prototypstyrplatta utförs också, och maskinens styrstrategi testaspå testbänken. Sammantaget kan maskinen fungera som en sexfasmaskinframgångsrikt.
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Points quantiques : caractérisation et applications en sciences pharmaceutiquesMoquin, Alexandre 03 1900 (has links)
L’imagerie médicale a longtemps été limitée à cause des performances médiocres des fluorophores organiques. Récemment la recherche sur les nanocristaux semi-conducteurs a grandement contribué à l’élargissement de la gamme d’applications de la luminescence dans les domaines de l’imagerie et du diagnostic. Les points quantiques (QDs) sont des nanocristaux de taille similaire aux protéines (2-10 nm) dont la longueur d’onde d’émission dépend de leur taille et de leur composition. Le fait que leur surface peut être fonctionnalisée facilement avec des biomolécules rend leur application particulièrement attrayante dans le milieu biologique.
Des QDs de structure « coeur-coquille » ont été synthétisés selon nos besoins en longueur d’onde d’émission. Dans un premier article nous avons modifié la surface des QDs avec des petites molécules bi-fonctionnelles portant des groupes amines, carboxyles ou zwitterions. L’effet de la charge a été analysé sur le mode d’entrée des QDs dans deux types cellulaires. À l’aide d’inhibiteurs pharmacologiques spécifiques à certains modes d’internalisation, nous avons déterminé le mode d’internalisation prédominant. L’endocytose par les radeaux lipidiques représente le mode d’entrée le plus employé pour ces QDs de tailles similaires. D’autres modes participent également, mais à des degrés moindres. Des disparités dans les modes d’entrée ont été observées selon le ligand de surface.
Nous avons ensuite analysé l’effet de l’agglomération de différents QDs sur leur internalisation dans des cellules microgliales. La caractérisation des agglomérats dans le milieu de culture cellulaire a été faite par la technique de fractionnement par couplage flux-force (AF4) associé à un détecteur de diffusion de la lumière. En fonction du ligand de surface et de la présence ou non de protéines du sérum, chacun des types de QDs se sont agglomérés de façon différente. À l'aide d’inhibiteur des modes d’internalisation, nous avons corrélé les données de tailles d’agglomérats avec leur mode d’entrée cellulaire.
Les cellules microgliales sont les cellules immunitaires du système nerveux central (CNS). Elles répondent aux blessures ou à la présence d’inflammagènes en relâchant des cytokines pro-inflammatoires. Une inflammation non contrôlée du CNS peut conduire à la neurodégénérescence neuronale et est souvent observée dans les cas de maladies chroniques. Nous nous sommes intéressés au développement d’un nanosenseur pour mesurer des biomarqueurs du début de l’inflammation. Les méthodes classiques pour étudier l’inflammation consistent à mesurer le niveau de protéines ou molécules relâchées par les cellules stressées (par exemple monoxyde d’azote, IL-1β). Bien que précises, ces méthodes ne mesurent qu’indirectement l’activité de la caspase-1, responsable de la libération du l’IL-1β. De plus ces méthode ne peuvent pas être utilisées avec des cellules vivantes.
Nous avons construit un nanosenseur basé sur le FRET entre un QD et un fluorophore organique reliés entre eux par un peptide qui est spécifiquement clivé par la caspase-1. Pour induire l’inflammation, nous avons utilisé des molécules de lipopolysaccharides (LPS). La molécule de LPS est amphiphile. Dans l’eau le LPS forme des nanoparticules, avec des régions hydrophobes à l’intérieure. Nous avons incorporé des QDs dans ces régions ce qui nous a permis de suivre le cheminement du LPS dans les cellules microgliales. Les LPS-QDs sont internalisés spécifiquement par les récepteurs TLR-4 à la surface des microglies. Le nanosenseur s’est montré fonctionnel dans la détermination de l’activité de la caspase-1 dans cellules microgliales activées par le LPS. Éventuellement, le senseur permettrait d’observer en temps réel l’effet de thérapies ciblant l’inflammation, sur l’activité de la caspase-1. / Medical imaging based on fluorescence has suffered from the poor photostability and mediocre performance of organic fluorophores. The discovery and subsequent improvements in nanocrystal synthesis and functionalization has greatly benefited the applications in medical imaging and the development of nanocrystal-based sensors for diagnostics. QDs are semi-conductor nanocrystals which have similar sizes as proteins (2-10 nm). They are highly luminescent, and can be made to emit at any desired wavelength by varying their size and composition. The surface of QDs can be easily functionalized with biomolecules. Hence, it is interesting to study how QDs interact in the biological world.
Highly luminescent core-shell QDs emitting at different wavelengths were prepared according to our needs. In a first study, the surface of the QDs was modified with various small bi-functional thiolated ligands (carboxylated, aminated and zwitterionic). The modified-QDs of nearly identical sizes were administered in vitro to study the impact of surface charge and cell type on the mode and extent of cell uptake and elimination. Using specific inhibitors of cell uptake we determined which modes contributed to the internalization of the QDs. Endocytosis mediated by lipid rafts represented the predominant pathway for the internalization of QDs. However, other modes contributed to a lesser degree, depending on the surface ligand.
We then analyzed the effect of QD agglomeration in cell culture media on its cellular uptake by microglia. Thorough characterization of QD agglomerate size distribution was conducted by asymmetrical flow field-flow fractionation (AF4) with a dynamic light scattering detector. Depending on the type of surface ligand and if serum proteins were present, the agglomeration pattern of the QDs was significantly different. With inhibitors of specific modes of cell uptake, we showed that the size distribution data, obtained by AF4, correlated with the modes of cell uptake.
Microglia cells are immune cells of the central nervous system (CNS). They respond to injury or the presence of inflammagens by producing pro-inflammatory cytokine. Inflammation in the CNS may lead to loss of neurons, and can found in many chronic diseases. We were interested in building nanosensors to measure the onset of inflammation. Current methods to study inflammation consist in measuring levels of certain proteins or chemicals released by stressed cell (e.g. Western blot or ELISA assay for IL-1β). Although precise, these methods measure indirectly the activity of the enzyme responsible for releasing IL-1β, i.e. caspase-1. Moreover, these methods cannot be applied to live cells.
We designed a sensor based on FRET between a QD and a dye linked by a peptide specifically cleaved by the caspase-1. To induce inflammation, we applied lipopolysaccharides (LPS), which are endotoxins present in Gram negative bacteria responsible for sceptic shock. The LPS form nanoparticles due to their amphiphilicity. The interior hydrophobic regions were used to load hydrophobic QDs, making the LPS luminescent. The microglia internalized LPS-QD predominantly through TLR-4 membrane receptors. We describe how the LPS induce inflammation and demonstrated the functionality of the QD-based sensor. Eventually, the sensor could be used to monitor in real time the action of therapeutics against inflammation.
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Diode laser 1.5 micron de puissance et faible bruit pour l’optique hyperfréquence. / High power, low noise 1.5 micron diode lasers for microwave photonics.Faugeron, Mickael 22 October 2012 (has links)
Cette thèse porte sur la conception, la réalisation et la caractérisation de diodes lasers de puissance, faible bruit à 1.5 µm sur InP pour des applications d’optique hyperfréquence, notamment pour des liaisons optiques analogiques de grande dynamique pour les systèmes radar. La première partie du travail a consisté à modéliser et concevoir des structures laser DFB ayant de faibles pertes internes. Ces structures, appelées lasers à semelle, incorporent une couche épaisse de matériaux entre la zone active et le substrat pour agrandir et délocaliser le mode propre optique des zones dopées p. La complexité de la conception résidait dans le bon compromis à trouver entre les performances statiques et dynamiques. Nous avons réalisé des diodes-lasers DFB avec une puissance > 150 mW, un rendement de 0.4 W/A, un niveau de bruit de 160 dB/Hz et une bande passante de modulation à 3 dB de 7.5 GHz. Les composants ont ensuite été caractérisés puis évalués dans des liaisons analogiques. Nous avons démontré des performances de gain de liaison, de dynamique et de point de compression à l’état de l’art mondial. En bande L (1-2 GHz) par exemple, nous avons montré des liaisons avec 0.5 dB de gain, un point de compression de 21 dBm et une dynamique (SFDR) de 122 dB.Hz2/3.En utilisant la même méthodologie de conception, la dernière partie du travail de thèse a été consacrée à la réalisation et à la caractérisation de lasers de puissance à verrouillage de modes pour la génération de train d’impulsions ultra-courts et la génération de peignes de fréquences. Ces structures présentent de très faibles largeurs de raie RF (550 Hz) et de très fortes puissances optiques (> 18 W en puissance crête). / This work focuses on the design, realization and characterization of high power, low noise 1.5 µm diode lasers for microwave applications and more particularly for high dynamic optical analog link for radar systems. The first part of this study deals with modeling and design of low internal losses DFB laser structures. These specific structures are called slab-coupled optical waveguide lasers, and are composed of a thick layer between the active layer and the substrate. The aim of this waveguide is to enlarge the optical eigenmode and to move the optical mode away from p-doped layers. The main difficulty was to find the good trade-off between laser static performances (optical power, efficiency) and dynamic performances (RIN and modulation bandwidth). We have succeeded in developing high efficiency (0.4 W/A), low noise (RIN ≈ 160 dB/Hz) DFB lasers with more than 150 mW and a 3 dB modulation bandwidth up to 7.5 GHz. We have then characterized our components on wide band and narrow band analog links. We have demonstrated state of the art gain links, dynamic and 1 dB compression power. In the L band (1-2 GHz) for example, we have obtained an optical link with a gain of 0.5 dB, a compression power of 21 dBm and a dynamic (SFDR) of 122 dB.Hz2/3.Finally we have applied the methodology and the design of slab-coupled optical waveguide structures to develop high power mode-locked lasers for ultra-short pulses generation and for optical and electrical comb generation. We have demonstrated narrow RF linewidth (550 Hz) lasers with very high power (continuous power > 400 mW and peak power > 18 W).
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Study of the aquatic dissolved organic matter from the Seine River catchment (France) by optical spectroscopy combined to asymmetrical flow field-flow fractionation / Étude de la matière organique dissoute aquatique dans le bassin versant de la Seine (France) par spectroscopie optique combinée au fractionnement par couplage flux/force avec flux asymétriqueNguyen, Phuong Thanh 06 November 2014 (has links)
Le but principal de cette thèse était d'étudier les caractéristiques de la matière organique dissoute (MOD) dans le bassin versant de la Seine. Ce travail a été réalisé dans le cadre du programme de recherche PIREN-Seine. Les travaux présentés ici visaient plus particulièrement à identifier les sources de MOD et à suivre son évolution dans les zones d’étude. L’analyse des propriétés optiques (UV-Visible, fluorescence) de la MOD, couplée aux traitements PARAFAC et ACP, a permis de discriminer différentes sources de MOD et de mettre en évidence des variations spatio-temporelles de ses propriétés. L’axe Seine, en aval de Paris, a notamment été caractérisé par l'activité biologique la plus forte. La MOD du bassin de l’Oise a montré des caractéristiques plus "humiques", tandis que le bassin de la Marne a été caractérisé par un troisième type spécifique de MOD. Il a d’autre part été mis en évidence la présence de MODs spécifiques dans chaque zone pour les échantillons prélevés en périodes d’étiage, alors qu’une distribution homogène des composants a été obtenue pour l’ensemble des échantillons prélevés en période de crue.Le rôle environnemental des colloïdes naturels étant étroitement lié à leur taille, il a d’autre part été développé une technique analytique/séparative originale pour l’étude de ce matériel complexe, un fractionnement par couplage flux/force avec flux asymétrique (AF4). Le fractionnement par AF4 des échantillons a confirmé la variabilité spatio-temporelle en composition et en taille de la MOD d'un site de prélèvement à un autre et a permis de distinguer différentes sources de MOD colloïdale confirmant les résultats de l’étude de ses propriétés optiques. / The main goal of this thesis was to investigate the characteristics of dissolvedorganic matter (DOM) within the Seine River catchment in the Northern part of France. ThisPhD thesis was performed within the framework of the PIREN-Seine research program. Theapplication of UV/visible absorbance and EEM fluorescence spectroscopy combined toPARAFAC and PCA analyses allowed us to identify different sources of DOM andhighlighted spatial and temporal variations of DOM properties. The Seine River wascharacterized by the strongest biological activity. DOM from the Oise basin seemed to havemore "humic" characteristics, while the Marne basin was characterized by a third specifictype of DOM. For samples collected during low-water periods, the distributions of the 7components determined by PARAFAC treatment varied between the studied sub-basins,highlighting different organic materials in each zone. A homogeneous distribution of thecomponents was obtained for the samples collected in period of flood.Then, a semi-quantitative asymmetrical flow field-flow fractionation (AF4) methodology wasdeveloped to fractionate DOM. The following optimized parameters were determined: across-flow rate of 2 ml min-1 during the focus step with a focusing time of 2 min and anexponential gradient of cross-flow from 3.5 to 0.2 ml min-1 during the elution step. Thefluorescence properties of various size-based fractions of DOM were evaluated by applyingthe optimized AF4 methodology to fractionate 13 samples, selected from the three sub-basins.The fluorescence properties of these fractions were analysed, allowing us to discriminatebetween the terrestrial or autochthonous origin of DOM.
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Extremely asymmetrical scattering of waves in periodic Bragg arraysPile, David Fujio Pelleas January 2003 (has links)
This thesis fills in the gaps in the existing theory of wave phenomena in thick diffraction gratings at extreme angles of scattering, i.e. when the scattered wave propagates parallel or almost parallel to the grating boundaries. A consistent theory of a new type of Bragg scattering of bulk and guided optical modes in thick uniform and non-uniform, dissipative and non-dissipative, slanted periodic gratings has been developed. This type of scattering is
called extremely asymmetrical scattering (EAS).
One of the main distinctive features of EAS is the strong resonant increase of the scattered wave amplitude compared to the amplitude of the incident wave. Several unique combinations of strong resonances shaping a complex multi-resonant pattern of EAS in different types of gratings have been predicted and investigated theoretically and numerically. This includes the prediction of a new resonant wave effect in non-uniform gratings with varying phase – double-resonant EAS, the discovery of several sharp and strong resonances with respect to scattering angle in gratings with the scattered wave
propagating almost parallel to the grating boundaries (grazing-angle scattering (GAS)) for the case of second-order scattering, and the prediction of a new type of eigenmode in gratings with second-order scattering (especially in gratings with large amplitude). In addition, several other important practical problems that may be crucial for the experimental observation and application of EAS and GAS have been solved. These are the determination of the tolerance of EAS to small grating imperfections, e.g., fluctuations of the grating amplitude, prediction
of unusually high sensitivity of second-order EAS to small variations of mean structural parameters, determination of the effect of weak dissipation on EAS, etc. Physical reasons for the predicted resonances and effects are explained. In particular, the crucial role of the diffractional divergence for EAS and GAS has been revealed, especially for non-uniform gratings.
Methods of analysis involve the approximate and rigorous approaches. The approximate method is based on understanding the role of the diffractional divergence in the geometry of EAS and the two-wave approximation (valid for any types of waves). The rigorous approach is based on the rigorous coupled-wave analysis (RCWA) and, in particular, the known enhanced T-matrix
algorithm (by Moharam, et al.) that is numerically stable for narrow and wide gratings with arbitrary amplitude (valid only for bulk electromagnetic waves).
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中國大陸運用經濟手段應對菲、越南海爭端 / China’s Employing Economic Instruments in Dealing with the South China Sea Disputes to the Philippines and Vietnam鄭藝銘, Cheng, I Ming Unknown Date (has links)
本研究旨在探討中國大陸如何運用經濟工具與菲律賓、越南應處南海爭端。參照Keohane及Nye非對稱互賴理論(asymmetrical interdependence)提出之敏感性(sensitivity)、脆弱性(vulnerability)概念,本研究分析中國大陸自1997年採取「魅力攻勢(Charm Offensive)」策略,為其創造可供運用經濟誘因(economic attraction)及經濟脅迫(economic coercion)之戰略空間,期能使菲、越等經濟實力相對弱勢國家,在領土爭端方面知所退讓。然而,從經濟誘因之敏感性以觀,研究發現菲、越兩國例證,均無以支持經濟誘因能說服相對弱勢國家減緩聲索之論述。針此,研究者提出「信任(trust)」或可作為補強Keohane及Nye分析框架要項之一;意即中國大陸與其經濟夥伴之間若政治信任不足,則中國大陸欲藉提供經濟誘因,促其經濟夥伴在領土爭端有所退讓,勢必存在相當難度。另從經濟脅迫之脆弱性以觀,研究發現菲、越兩國例證顯示,有別於運用實質性手段(substantive measures)施壓造成之短期損失,採取象徵性手段(symbolic measures)所映射之高度風險與不確定性,對於威懾經濟實力相對弱勢國家,可能更具效力。 / This study explores how China has employed economic instruments in handling South China Sea disputes with the Philippines and Vietnam. Borrowing Keohane and Nye’s notations of sensitivity and vulnerability in asymmetrical interdependence, this study analyzes how China’s charm offensive strategy developed since 1997 has created tactical spaces for China to utilize economic attractions and economic coercions in making her weaker economic partners to concede in territorial disputes. In terms of sensitivity to economic attractions, nevertheless, findings in both cases fail to support the argument that economic incentives would persuade the weaker parties to refrain their claims. I argue that one of the missing elements in Keohane and Nye’s analytical framework is “trust”. Without sufficient political “trust” between China and her economic partners, economic attractions to induce concessions could hardly work. In terms of vulnerability to economic coercions, findings in both cases suggest that compared to the substantive measures stressing the short-term loss, the symbolic measures projecting to high degree of risks and uncertainties might be more effective to deter the weaker parties.
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Développement méthodologique du fractionnement par couplage flux / force (AF4) et spectroscopie optique pour l'étude de la matière organique dissoute aquatique : application aux estuaires de Seine et de Gironde / Methodological development of flow field-flow fractionation (AF4) and optical spectroscopy for the study of aquatic dissolved organic matter : application to the Seine and Gironde estuariesParot, Jeremie 09 December 2016 (has links)
La matière organique dissoute (MOD) est constituée d’un mélange hétérogène et complexe de molécules. Elle intervient dans de nombreux processus physiques, biologiques et chimiques dans les milieux aquatiques, et notamment dans les grands cycles biogéochimiques ou le transport et la biodisponibilité des contaminants.Ainsi un des enjeux actuels de nombreux domaines de recherche (chimie, écologie, océanographie) est de mieux comprendre et caractériser la MOD dans l’environnement. Dans ce contexte-là, l’objectif de ces travaux a été le développement d’une méthodologie analytique pour l’analyse et la séparation, en fonction de la taille, par fractionnement par couplage flux-force avec flux asymétrique (AF4) de la MOD. Le développement a principalement porté sur la phase mobile, le flux croisé, le temps de focus et l’utilisation d’étalons organiques proches de la MOD, permettant de calculer sa masse moléculaire moyenne.Cette méthode optimisée, couplée à un détecteur UV/Vis, équipée d’une membrane de 1kDa, d’un espaceur de 490μm et d’une phase mobile de 5mM en tampon phosphate a permis l’étude de la dynamique de la MOD.L’application de cette méthode couplée aux techniques de spectroscopie optique (absorbance et fluorescence) a permis l’étude de la MOD dans les estuaires de Seine et de Gironde mettant en avant les effets de la marée et des saisons sur la taille et le type de MOD.De plus, différentes approches statistiques ont été développées afin de mieux appréhender les multiples variables (analytiques ou environnementales) et notamment les modèles de régression linéaire ou les cartes auto-organisatrices de Kohonen. / Dissolved organic matter (DOM) is a heterogeneous and complex mixture of molecules. It is involved in many physical, biological and chemical processes in aquatic ecosystems, especially in the major biogeochemical cycles or transport and bioavailability of contaminants.Thus one of the current issues in many areas of research (chemistry, ecology, oceanography) is to better understand and characterize DOM in the environment. In this context, the aim of this work was the development of an analytical methodology for DOM analysis and separation, depending on its size, by asymmetrical flow field-flow fractionation (AF4). The development focused on the mobile phase, the cross-flow, the focus time and the use of organic macromolecules standards close to DOM, in order to calculate its molecular weight.This optimized method, coupled with a UV/Vis detector, equipped with a 1kDa membrane, a 490μm spacer and a mobile phase of 5 mM phosphate buffer allowed us to study the MOD dynamics in estuarine environments.The application of this method coupled to optical spectroscopy techniques (absorbance and fluorescence) permitted the study of MOD in the Seine and Gironde estuaries and to highlight the tidal and the seasonal effects on the size and type of DOM.Furthermore, different statistical approaches have been developed to better understand the multiple variables (analytical or environmental), especially linear regression models or self-organizing maps (Kohonen).
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