Tesi: "Surfaces actives"

1

Berthet, Guillaume. "Revêtements diamant pour surfaces actives sur capteurs du domaine pétrolier". Electronic Thesis or Diss., Paris 6, 2017. http://www.theses.fr/2017PA066660.

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Dans le domaine pétrolier les alliages de nickel tels que l’Inconel sont majoritairement utilisés au cours des forages pour leur bonne résistance mécanique et chimique face à H2S, CO2 ou des acides carboxyliques. Cependant, en dépit de leurs excellentes propriétés, les parties sensibles des capteurs réalisés à partir de ces matériaux voient leurs performances altérées par les environnements hostiles de forages (conditions hautes pressions et hautes températures), la corrosion et l’abrasion. De plus, ces capteurs peuvent être exposés à divers fluides, durant un même forage, contenant des particules solides ou de très grosses molécules organiques telles que les asphaltènes, paraffines ou résines qui ont tendance à s’agglomérer sur les surfaces hydrophiles métalliques. Le diamant a été identifié comme un excellent candidat pour la fabrication de revêtements de protection pour des capteurs embarqués lors de forages pétroliers. En effet, le diamant offre une excellente résilience mécanique, une grande inertie chimique, un module d’Young élevé et une résistance à l’encrassement qui font de lui un matériau parfaitement adapté pour une utilisation en conditions hostiles. Cependant la réalisation d’un dépôt de diamant sur Inconel ne peut pas être réalisée via les solutions usuelles de MP-CVD. Les résultats de cette étude présentent trois différents procédés permettant d’obtenir un revêtement diamant adhérent sur des pièces 3D d’Inconel718. Ces procédés se différencient par leur rugosité et leur complexité de mise en œuvre. Leurs bénéfices sur des capteurs de densité-viscosité ont été évalués face à divers fluides pétroliers particulièrement encrassants. Pour lutter contre ces encrassements, deux approches ont été identifiées comme étant prometteuses : (i) développer des surfaces exploitant l’effet Lotus en réalisant une microstructure superhydrophobe, et (ii) optimiser un traitement électrochimique permettant de nettoyer des surfaces in-situ sans intervention humaine. Cette étude a permis de comprendre les mécanismes réactionnels en mettant en avant le rôle de la dégradation de l’eau lors du traitement électrochimique. Grace à cela, ces travaux indiquent les conditions d’utilisations et les limites du procédé. De plus le potentiel de cette technique face à des fluides de forage et du pétrole brut a été démontré avec succès
In the field of oil and gas industry, Inconel alloys are largely used for their high strength and good corrosion resilience to H2S, CO2 and carboxylic acids. However, those of despite their excellent properties compare to other alloys, some specific oil and gas parts such as the sensitive areas of some sensors may require a special attention as high pressure high temperature (HPHT) environment, corrosion and abrasion may affect their performances in the long term. Additionally, oil and gas sensors may often be exposed, during the same drilling work, to various drilling fluids containing hydrophilic solid particles or heavy molecules such as asphaltenes, resins or heavy alkanes which tend to aggregate on hydrophilic alloy surfaces. Diamond coatings have thus been identified as attractive candidates to protect sensor used during drilling operations. Indeed, diamond materials due to their excellent hardness and wear, low friction coefficient, corrosion resilience and chemical inertness further to high natural resilience to fouling are especially suitable to be used in harsh environments. However, diamond coating on Ni-alloy such as Inconel could not be done by MP-CVD common processes. The current study has proposed solutions, and namely the development of three different processes aiming at a strong and adherent diamond coating on Inconel718. These three processes differ by their roughness and their difficulties of implementation. Their advantages for density-viscosity sensors have been assessed in various drilling fluids, and two specific approaches have been identified as particularly promising to mitigate fouling, namely (i) to create a diamond superhydrophobic surface through micro-structuration to get the antifouling Lotus properties, and (ii) the optimization of an electrochemical treatment aiming at cleaning in situ the diamond surfaces downhole. This study has led to propose reaction mechanisms and demonstrated the role of degraded water on the electrochemical treatment. The thesis has demonstrated the potentialities and identified the limits of those approaches. Efficiency of the electrochemical process applied to drilling fluids and crude oils fouling have been successively demonstrated

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2

Breton, Sylvain. "Dynamique des surfaces planétaires actives : quantification des paysages, modélisation et inversion". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1280.

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Les cratères d'impact sont indispensables dans l'étude des surfaces planétaires. D'une part, les statistiques de leur nombre permet de dater les surfaces planétaires, d'autre part, leur forme révèle les processus de surface qu'ils ont connu. Cette thèse propose de coupler les études statistiques et morphologiques afin d'étudier la temporalité et l'importance des processus sédimentaires et/ou volcaniques des surfaces planétaires. L'utilisation de la profondeur des cratères permet de rajouter une dimension aux distributions avec l'introduction des distributions en fréquence de taille et de profondeur (SDFD), offrant ainsi un aperçu des modifications morphologiques des cratères. Nous avons développé en conséquence des modèles permettant de modéliser l'évolution d'une population de cratères en prenant en compte les phénomènes d'oblitération. La surface Mars est largement cratérisée, mais ils ont pour la plupart été fortement modifiés par des processus volcaniques et/ou sédimentaires. A partir des SDFDs, nous avons estimé les taux d'oblitération martiens à une échelle globale. Ces taux sont, au Noachien, de plusieurs milliers de m/Ga, mais décroissent rapidement dès l'Hespérien inférieur et sont proches de 0 à l'Amazonien. L'oblitération sur la province de Tharsis a décru beaucoup moins rapidement suggérant une persistance du volcanisme à l'Amazonien inférieur. Les plaines du nord à l'Amazonien sont marqué par des taux d'oblitération un ordre de grandeur au-dessus du reste de la planète, qui pourraient indiquer la mise en place continue de la Vastitas Borealis Formation au cours de l'Amazonien moyen. En complément de notre approche à l'échelle globale, nous avons déterminé des taux d'oblitération actuels à partir de cartographies de cratères réalisées à haute résolution spatiale sur des sites d'atterrissage de rovers actuels et futurs. Les sites de Mawrth Vallis et d'Oxia Planum présentent les taux d'oblitération actuels les plus importants en particulier au niveau de leurs unités geologiques riches en minéraux hydratés
Impact crater are often used in the study of planetary surfaces. On the one hand, statistics on crater number provide the age of the surface, on the other hand, their shapes reflect the surface processes they witnessed. This study combines the statistic and morphology approaches in order to investigate the timing and intensity of sedimentary and volcanic processes of planetary surfaces. The use of crater depth measurements add a dimension to frequency distributions with the introduction of size and depth frequency distribution (SDFD). SDFSs can be interpreted in term of crater obliteration rates thanks to crater chronology models. We also developed models of crater population taking into account obliteration. Mars surface is highly cratered with many craters displaying signs of modifications by volcanic process, sedimentation and erosion. We interpreted SDFDs using a classic crater chronology system, to produce global maps of obliteration at different epochs of Mars. During Noachian, obliteration rates reach several thousands m/Gy, but rapidly decrease during early Hesperian and are close to 0 during Amazonian. Obliteration on the province of Tharsis decreased slower, suggesting a persistence of volcanic activity until early Amazonian. Northern lowlands witness Amazonian obliteration rates one order of magnitude higher than the rest of the planet, which may indicate the continuous formation of Vastitas Borealis during middle Amazonian. In addition to our global approach, we computed recent obliteration rates from mapping of high resolution images on landing sites of rover missions. Mawrth Vallis and Oxia Planum present significant obliteration rates, especially on units containing hydrated minerals

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3

Gouaillard, Alexandre. "Contexte générique bi-multirésolution basé ondelettes pour l'optimisation d'algorithmes de surfaces actives". Lyon, INSA, 2005. http://theses.insa-lyon.fr/publication/2005ISAL0073/these.pdf.

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Segmentation is a crucial stage of anatomical data analyzis. Some applications among which screening of transgenic mice, require a robust and quick segmentation step to catch the high trhoughput rates. Robustness in segmentation is achived by means of a priori models represented as discrete surfaces and deformed by active contour algorithms. This segmentation technics, already exisiting (Kess et al. , 1988 - Cohen, 1991) is efficient and has been intensively used. Nowadays discrete model tend to increase in size (104 to 106 nodes) and so is the computational cost. Multi levels and/or multi resolution approaches on images have been used, succesfully, to yet improve the robustness and the speed. However, up to now, no multiresolution scheme has been applied on the model. The main goal of the work is to improve the speed and the robustness of active contour algorithms thanks to multiresolution approaches on both model and data. The result of this work is a bi-multiresolution framework within which any given active surface algorithm could be plugged. A mathematical study of the computational cost of the resultng algorithm shows that we can hope to speed up the algorithm by a factor 3. In real cases, gains of a factor 100 have been reached
Dans le cadre de l'analyse de données anatomiques, la segmentation est une étape indispensable. Certaines applications (criblage par imagerie de souris transgénique, par exemple) nécessitent impérativement de réaliser cette opération de manière rapide et robuste pour respecter les contraintes de débits d'acquisition et d'automatisation de l'analyse. La robustesse dans la segmentation des organes anatomiques est obtenue en s'appuyant sur des modèles maillés déformés par des techniques de type contours actifs. Cette stratégie de segmentation, déjà ancienne (Kass et al. , 1988 – Cohen, 1991) est pertinente et a fait ses preuves. Compte tenu de la taille des modèles utilisés (104 à 106 sommets), le temps de calcul pour la segmentation est très élevé. Des approches multi échelles et/ou multirésolution sur images ont déjà été utilisées avec succès pour améliorer la robustesse et la vitesse de convergence. Mais jusqu'ici, ce type d'approches n'avait pas été appliqué au modèle. L'objectif principal de la thèse est d'accélérer les méthodes de contours actifs / surfaces actives grâce à une décomposition multirésolution sur bases d'ondelettes des données et du modèle comme illustré par l'image précédente. Le résultat de la thèse est un environnement d'optimisation générique dans lequel n'importe quel algorithme de surface active discrète peut être plongé. Une modélisation mathématique de l'algorithme ainsi construit démontre un gain en complexité d'un facteur 3 dans le domaine d'utilisation envisagé. De plus, la convergence est encore accélérée par l'approche multirésolution, ce qui permet d'atteindre dans les cas réels des gains en vitesse de l'ordre de 100

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4

Kurylo, Ievgen. "Surfaces actives pour l'activation contrôlable de la programmation moléculaire basée sur l'ADN en microfluidique". Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1I073/document.

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Les organismes vivants prennent des décisions en permanence à l’aide de réseau de réactions chimiques couplées (CRN) les unes aux autres. Cette capacité a inspirée de nombreux scientifiques qui cherchent aujourd’hui à construire des versions synthétiques de ces réseaux pour créer des systèmes dynamiques complexes. Les molécules d’ADN constituent une solution idéale pour construire de tels CRNs. Le travail de recherche présenté dans ce manuscrit vise à développer des surfaces actives qui permettent d’interagir avec la PEN toolbox en environnement microfluidique afin de pouvoir utiliser pleinement le potentiel de tels systèmes moléculaires. Nous avons étudié l’utilisation de la PEN toolbox en microfluidique en explorant différents paramètres. Nous discuterons ensuite de la réalisation de surfaces actives et de leur caractérisation. Celles-ci sont concues pour permettre l’immobilisation de brins d’ADN via une liaison thiol et leur largage en solution en rompant électro-chimiquement cette liaison. Nous discuterons également d’aspect technique permettant l’intégration aisée d’une telle stratégie dans des dispositifs microfluidiques. Par la suite, nous montrerons qu’il est possible de contrôler spatio-temporellement le largage d’instructions à base d’ADN. Pour ce faire, nous nous appuierons sur une version plus évoluée de l’auto-catalyseur présenté précédemment. Nous mettrons en évidence qu’il est possible d’initier de façon contrôlée des phénomènes de réaction-diffusion dans des canaux microfluidiques.Pour finir, nous ouvrirons des perspectives pour la conception de surface actives permettant un niveau de contrôle encore plus grand des systèmes moléculaires
Living organisms perform complex information processing tasks with a help of intertwined chemical reaction networks (CRNs) and diffusion processes. These biological phenomena inspired scientists to design from the bottom-up dynamical systems with complex spatiotemporal behaviour. DNA provides a perfect solution for building these synthetic CRNs. Our research work focused on designing active surfaces with the aim to provide a convenient way to interact in microfluidics with the PEN toolbox (as an example of DNA-based CRNs) and explore the full potential of these novel biochemistry tools. We will study the step by step assembly and optimisation of the PEN toolbox parameters. Next, we will discuss the construction and characterisation of active surfaces, which provide loading and controllable release of DNA input, based on formation and electrochemical cleavage of gold-thiol bond. We will also provide a technological solution to integrate these surfaces and the PEN toolbox in microfluidics. We will show controllable triggering of basic activation and autocatalysis PEN toolbox modules. We will further apply our method for spatiotemporal control of autocatalytic CRNs, which have higher stability then simple autocatalytic module while still providing an exponential signal amplification contrary to the activation module. This approach allows us to investigate and optimise the parameters of our technology. Finally, we will discuss the construction of active surfaces with irreversibly bound DNA, which provides a higher level of the PEN toolbox spatiotemporal behaviour, based on electrical polarisation and tuning the shape of surface-attached DNA patterns

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5

Gouaillard, Alexandre Odet Christophe. "Contexte générique bi-multirésolution basé ondelettes pour l'optimisation d'algorithmes de surfaces actives avelet-based bi-multiresolution framework for active contour models /". Villeurbanne : Doc'INSA, 2006. http://docinsa.insa-lyon.fr/these/pont.php?id=gouaillard.

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6

Hurtrez, Guy. "Etude des copolymères poly(styrène-b-oxyde d'éthylène) : synthèses, propriétés colloïdales et tensio-actives". Mulhouse, 1992. http://www.theses.fr/1992MULH0257.

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Des copolymères séquencés polystyrène-poly(oxyde d'éthylène) à caractéristiques variées ont été préparés par voie anionique et caractérisés. Leur fonctionnalisation par des groupes sulfonates et carboxylates a été réalisée avec un rendement de 90%. Une étude viscosimétrique a montré leur comportement particulier en milieu tétrahydrofuranne et toluène. La fonctionnalisation de polymères par des composés du type triazine a été utilisée pour tenter de préparer par désactivation des copolymères de structure particulière. Des molécules chromophores type anthracène et phénanthrène ont été incorporées à la jonction des séquences hydrophiles et hydrophobes avec un rendement de 100%. La micellisation en milieu aqueux des copolymères a abouti à une méthode de préparation des solutions qui permet d'étendre considérablement la gamme des copolymères micellisables en évitant la formation d'agrégats. L'analyse de ces solutions par diffusion de la lumière a montré qu'il existe une relation entre le rayon de la micelle et les caractéristiques moléculaires du copolymère. L'influence de la fonctionnalisation et du marquage fluorescent sur la taille des micelles a également été étudiée. Le transfert d'énergie non radiatif entre les molécules chromophores incorporées dans les copolymères a permis de mettre en évidence la micellisation en milieu aqueux. La formation de la micelle en milieu solvant/solvant sélectif et la concentration micellaire critique ont ainsi pu être détectées et mesurées

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7

Sefti, Rania. "Méthodes d'approximation de contours et de surfaces actifs pour la segmentation d'images médicales". Electronic Thesis or Diss., Orléans, 2024. http://www.theses.fr/2024ORLE1037.

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L'extraction automatique d'informations et la détection d'objets à partir d'images médicales ont connu un essor considérable ces dernières années. Ces avancées offrent aux cliniciens de nouvelles possibilités d'exploration et d'aide au diagnostic. Cependant, le processus de segmentation demeure complexe et présente de nombreux défis.Ce travail de thèse vise à développer des méthodes de segmentation d'images médicales basées sur les B-Snakes. En exploitant les propriétés des fonctions splines, nous avons amélioré la précision et la performance des contours actifs paramétriques (ou surfaces actives) pour la segmentation d’images médicales. Tout d'abord, nous avons introduit une nouvelle fonction d'approximation spline d'Hermite généralisée avec un support optimal et une erreur d'interpolation contrôlée. Ensuite, en utilisant un modèle d'apprentissage profond,nous avons développé un nouveau terme d'énergie qui met en avant l'importance de l'analyse des variations d'intensité et des textures. Puis nous avons introduit une étape d'équilibrage, fondée sur la géométrie de l'objet et de ses propriétés de courbe/surface. Ceci permet d’aligner la surface équilibrée du Snake avec les parties complexes de l'objet. Enfin, nous avons introduit un nouvel algorithme de déformation du Snake appelé méthode de déformation itérative progressive (PID). Celui-ci adapte itérativement les points de contrôle pour construire une série de courbes d'ajustement jusqu'à ce que la limite de l'objet soit détectée, sans qu'il ne soit nécessaire de résoudre les problèmes de minimisation de l'énergie. Les techniques proposées ont été rigoureusement évaluées, démontrant ainsi leur efficacité et leur robustesse dans diverses conditions d'application incluant un large éventail de données et différentes modalités d'imagerie
Automatic information extraction and object detection from medical images has advanced significantly in recent years. These advances offer clinicians new opportunities for exploration and diagnostic support. However, the segmentation process remains complex and presents many challenges. The aim of this thesis is to develop medical image segmentation methods based on B-Snakes. By exploiting the properties of spline functions, we have improved the accuracy and performance of parametric active contours (or active surfaces) for medical image segmentation. First, we introduced a new generalised Hermite spline approximation function with optimal support and controlled interpolation error. Then, using a deep learning model, we developed a new energy term that emphasises the importance of intensity variation and texture analysis. We then introduced a balancing step based on the geometry of the object and its curve/surface properties. This aligns the balanced Snake surface with the complex parts of theobject. Finally, we introduced a new snake deformation algorithm called Progressive Iterative Deformation (PID).This iteratively adjusts the control points to construct a series of fitting curves until the boundary of the object isdetected, without the need to solve energy minimisation problems. The proposed techniques have been rigorously evaluated, demonstrating their effectiveness and robustness under a variety of application conditions, including a wide range of data and different imaging modalities

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8

Moura, Tulio-Flavio. "Relations interfaciales, entre molécules actives végétales et substances auxiliaires, induites par la nébulisation : application aux extraits de Ruscus aculeatus L. et Malpighia glabra L". Montpellier 1, 1994. http://www.theses.fr/1994MON13520.

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9

Nguyen, Hoang Truc Phuong. "Formulation de nanosystèmes et évaluation de leur potentiel pour la délivrance cutanée de molécules actives". Thesis, Tours, 2015. http://www.theses.fr/2015TOUR3806/document.

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Ces travaux visent à déterminer l‘intérêt de deux types de nanosystèmes (NS) coeur-couronne dans des applications dermatologiques ou cosmétiques. Les nanocapsules lipidiques (LNC) sont obtenues par une méthode déjà décrite dans la littérature. Leur formule est modifiée pour incorporer un actif cosmétique d‘intérêt. Les nanocapsules d‘alginate (ANC) sont développées au moyen de plans d‘expériences. Elles sont composées d‘un coeur huileux et d‘une coque d‘alginate de calcium gélifiée obtenue par gélification ionique de surface d‘une nanoémulsion. Des méthodes basées sur le phénomène de fluorescence nous permettent de mettre en évidence l‘endocytose des ANC par les kératinocytes. Leur contenu est rapidement libéré dans le cytoplasme. Une étude sur différents modèles ex vivo montre que les deux nanosystèmes permettent aux molécules encapsulées d‘atteindre les couches vivantes de l‘épiderme. ANC et LNC sont stables plusieurs mois dispersées dans des formes galéniques semi-solides. Ces deux NS sont donc adaptés à la délivrance de molécules actives dans la peau
Two types of core-shell nanosystems have been evaluated for dermatological and cosmetic applications. Lipid nanocapsules (LNC) are obtained by a method that has already been described in the literature. Their composition is adapted for incorporation of a specific cosmetic ingredient. Alginate nanocapsules (ANC) are developed with the aid of experimental design. They consist of a triglyceride core with a rigid calcium alginate shell obtained by ionic gelation of the surface of a nanoemulsion. By incorporating fluorophores into these nanosystems, they can be studied by advanced spectral fluorescence imaging methods. We were thus able to show that ANC are first internalized into keratinocytes by endocytosis, and once inside the cells, their contents are rapidly released into the cytoplasm. A study of different ex vivo skin model systems has shown that both nanosystems enable active substances to reach the living epidermis. When incorporated into gels similar to those used as galenic forms for topical administration, LNC and ANC remain stable for months. They can thus be used as vectors for delivering active substances to the skin

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10

Khan, Suleman Manawar. "Surface active lanthanide complexes for sensing applications on silica and gold surfaces". Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/5726/.

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The work presented in this thesis investigates the use of new luminescent lanthanide bis-amide DTPA complexes, both in solution and bound to gold and silica surfaces. The bis-amide arms have been modified with surface attachment groups consisting of disulphides, thioacetates and silyl ethers. Both sensitising and non-sensitising bisamides arms were attached to DTPA in order to develop the best lanthanide based sensor. When these visible and NIR emitting lanthanide complexes are bound to the surface they can be used to detect various small analytesm including benzoic acid, phthalic acid, isophthalic acid, picolinic acid, dipicolinic acid, quinaldic acid, dibenzoyl methane and curcumin. The detection of analytes was performed on surfaces and in solution allowing for comparisons between the two techniques to be made. Lanthanide complexes were attached to silica microparticles and they were used for detection of analytes under flow conditions; these studies were compared to surface and solution analyte detection. The lanthanide-based silica microparticles were developed further to show the advantages of bimodal luminescent silica microparticles. The development of self-assembled monolayers of the lanthanide complexes on gold were studied using surface plasmon resonance and ellipsometry.

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11

BIGNARDI, Samuel. "Complete Waveform Inversion Approach To Seismic Surface Waves And Adjoint Active Surfaces". Doctoral thesis, Università degli studi di Ferrara, 2011. http://hdl.handle.net/11392/2388824.

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The idea to exploit the dispersive mechanism of surface waves as a probing tool for investigating subsurface structure was introduced about 30 years ago, and afterwards a very intense research field has developed. Currently many methods known generally as Surface Wave Methods exist, and are well established, most of them assuming layered or depth dependent ground models. In most cases the parallel layer assumption is correct because the soil structure is expected to negligibly depart from a layered structure at a typical surface testing scale for engineering and geotechnical purposes however to exploit the amount of information achievable, it is necessary to extend the research, relaxing at least one of the underlying model assumptions. Indeed in classical SWM’s, surface waves are assumed to be Rayleigh waves, this means that a parallel layered model has been implicitly assumed. As a consequence search for a soil model geometry other than the assumed one can only result in slight perturbations. The only possible deduction is that overcoming limitations of layered models requires to exploit P and S waves which are indeed general solutions of the elastodynamic problem. Geometry can then be retrived by a complete waveform inversion based on a forward model capable of successfully reproducing all of the features of the displacement field in presence of complex scattering phenomena. In this research effort an inversion approach has been introduced which exploits the Boundary Element Method as forward model. Such approach is appealing from a theoretical point of view and is computationally efficient. Although in the present work a monochromatic signal traveling in a system constituted by a layer over an half space was investigated, this method is suitable for any number of layers, and multi-frequency environments. The boundary element approach can be easily generalized to three-dimensional modeling; moreover viscoelasticity can be introduced by the elasticviscoelastic principle of correspondence. Finally BEM can be easily implemented for parallel computing architecture. Synthetic cases of high and low impedance Jump were investigated for typical SWM setups and a first example of application on real data was performed. Finally an elegant analytic form of the minimization flow named Adjoint Active Surfaces was obtained combining Computer Vision technique of Active surfaces and the Adjoint Field method.

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12

Parker, Emily M. "Surface active polymers as anti-infective and anti-biofouling materials". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:54e462df-b64c-499c-94ce-55d624be9a69.

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This thesis is concerned with the chemical modification of polymers in the preparation of a library of materials which exhibit altered surface properties as a result of the surface chemical functionality, with particular emphasis on the development of materials that control biofouling and are antibacterial. Chemical modification of crosslinked polystyrene, in film and microsphere form, was carried out by carbene insertion followed by diazonium coupling. This provided access to a collection of materials with varying surface chemistry, whilst the bulk properties of the polystyrene substrates were maintained. Synthesis of the diaryldiazo and the diazonium salts used to perform the surface modifications is described, as well as the preparation and characterisation of the materials. Analysis of the ability of the materials to adsorb and bind the protein bovine serum albumin (BSA) is presented with data obtained from two methods of observation. Quartz Crystal Microbalance with Dissipation (QCM-D) and a protein assay based on the change in optical density of a BSA/PBS solution are used to demonstrate how the specific surface chemistry of the materials influences the ability to adsorb and bind protein. The behaviour of the materials was time dependent and was rationalised with respect to the surface water contact angle and the calculated parameters polar surface area and % polar surface area of the functional groups added to the surfaces. Finally, penicillin loaded materials were prepared and their antibacterial activity was tested against E. coli and S. aureus, demonstrating that the antibiotic is still active from within the polystyrene scaffold.

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13

Chang, Teck Keng. "Active frequency selective surfaces". Thesis, University of Kent, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281659.

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14

Khalil, Karim S. (Karim Samir). "Active lubricant-impregnated surfaces". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92136.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 47-50).
This thesis presents the design and testing of actively controlled lubricant-impregnated surfaces for enhanced droplet mobility and manipulation. Droplet manipulation and mobility on non-wetting surfaces is of practical importance for diverse applications ranging from micro-fluidic devices, anti-icing, drop-wise condensation and biomedical devices, however most of the time droplets are moved passively. The use of active external fields has been explored via electric, acoustic and vibrational fields, yet moving highly conductive and viscous fluids remains a challenge. Magnetic fields have been used for droplet manipulation, however the fluid is usually functionalized to be magnetic, and requires enormous fields of superconducting magnets when transitioning to diamagnetic materials such as water. This thesis presents a new class of active surfaces by impregnating active fluids such as ferrofluids into a textured surface. Droplets on such ferrofluid-impregnated surfaces have extremely low hysteresis and high mobility such that they can be propelled by applying relatively low magnetic fields. Our surface is able to manipulate a variety of materials including diamagnetic, conductive and highly viscous fluids, and additionally solid particles. The surface's droplet propulsion mechanism is described, and is demonstrated to operate independently of the fluid or solid's physical properties that normally inhibit motion (such as conductivity, viscosity, magnetization). In addition, several previous methods for droplet manipulation require pre-fabricated channels that govern the path of the fluid, however we are able to achieve precise control of droplets on a free surface along complex paths, which allows for the use of a single surface for any number of lab-on-a-chip applications and designs.
by Karim S. Khalil.
S.M.

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15

Saini, Seema. "Modification de la surface de la nanocellulose pour conférer des propriétés actives pour emballage". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI113.

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Le projet de thèse a permis de proposer des stratégies "verte" pour la modification chimique de nanofibrilles de cellulose (CNF) afin de leur conférer des propriétés antimicrobiennes. Sept différentes CNF fonctionnalisées ont été produites en tenant compte des principes de développement durable et de la faisabilité industrielle dans le domaine des emballages de nouvelles générations. Dans un premier temps, les CNF ont été fonctionnalisées avec de la cyclodextrine pour contrôler le relargage de molécules actives. Dans d'autres stratégies, des surfaces antimicrobiennes par contact ont été préparées en greffant des molécules naturelles ou en suivant les principes de biomimétisme. Les résultats sont très prometteurs et permettent l'obtention de surface clairement antimicrobienne sans relargage de molécules. Des caractérisations de grandes qualités ont confirmé ces greffages (par exemple, XPS, RMN, QCM-D) ainsi que les propriétés antimicrobiennes (par rapport à la S.aureus ou E.Coli). Une des meilleurs stratégies utilisant des CNF greffées avec des antibiotiques, a été produites à l'échelle laboratoire mais aussi implémentée à l'échelle semi-industrielle, avec pour objectif final la production d'emballages médicaux limitant les maladies nosocomiales
The present investigation has developed efficient green strategies for the chemical modification of cellulose nanofibers (CNF), in order to impart antimicrobial activities. Seven different functionalized CNF was produced in this context keeping in mind sustainability and industrial feasibility within new generation packaging field. First, CNF was designed with cyclodextrin to control the release of natural active molecules. In other strategies, non-leaching contact active antimicrobial surfaces were prepared using natural active molecules or following biomimetic approaches. Results are very promising and allow obtaining efficient antimicrobial surface without any release. High level characterizations confirm surface grafting (e.g. XPS, QCM-D, NMR) and anti-microbial efficiency (S.aureus, E.Coli). One of the best strategies using antibiotic grafted CNF was produced at lab scale but also implemented at semi industrial scale. The final idea was to produce medical packages limiting the cross contamination in hospitals

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16

Charles-Blin, Youn. "Technologie de protection active des électrodes par fluoration de surface". Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS068.

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Un changement de cap vers les technologies vertes est impulsé par les instances dirigeantes Européennes, désormais d’importants efforts sont engagés pour réduire notre empreinte carbone d’au moins 40% d’ici à 2030. Le développement de batteries sûres, présentant de meilleures densités d’énergie s’inscrit dans cette démarche. Ces technologies sont incontournables pour la croissance du secteur des transports électriques et des réseaux électriques intelligents. Pour répondre à la demande, de nouveaux matériaux doivent être développés et les matériaux existants doivent être améliorés pour atteindre de meilleures capacités de stockage et de plus hauts potentiels de travail. La recherche prospecte de nouveaux matériaux d’électrodes, de nouveaux électrolytes, mais aussi de nouvelles stratégies pour protéger les interfaces électrodes/électrolyte au cœur des batteries. En effet, dans les batteries secondaires, les interfaces électrodes/électrolyte jouent un rôle déterminant dans les performances électrochimiques et les durées de vie. Les électrolytes liquides organiques subissent des dégradations dans les fenêtres de potentiels appliqués conduisant à la formation d’une couche à la surface des électrodes négatives appelée « Solid Electrolyte Interphase » (SEI). La formation de cette interface amène une problématique à double tranchant : la SEI diminue l’efficacité coulombique et provoque des pertes de capacité irréversibles, mais elle permet également la passivation de l’électrode et prévient les mécanismes de vieillissements. Sachant cela, toute modification de la SEI se révèle délicate puisque l’équilibre entre les aspects positifs et négatifs peut être perdu. Par la chimisorption d’une fine couche fluorée à la surface des matériaux d’anode, nous sommes parvenus à améliorer le pouvoir passivant de la SEI à la surface de matériaux TiO2 et Li4Ti5O12 (LTO), conduisant à l’amélioration des comportements électrochimiques. Nous avons déterminé que de faibles quantités de fluor à la surface des matériaux actifs peuvent suffire à apporter de nombreuses améliorations. De plus, nous avons démontré que la fluoration est également bénéfique pour les matériaux d’électrodes positives tels que LiNi0.8Co0.15Al0.05O2 (NCA). En effet, le matériau NCA souffre d’instabilités structurales en surface qui entrainent des dégradations des capacités. Des comportements électrochimiques améliorés ont été observés pour des électrodes NCA fluorées, la fluoration permettant une stabilisation de la structure de surface du NCA.Nous avons prospecté l’influence de la fluoration de surface des matériaux actifs aux interfaces avec l’électrolyte, au moyen d’une approche multiéchelle. La nature chimique de la couche fluorée en surface des matériaux d’électrodes positives et négatives a été décrite par XPS, tout comme la distribution spatiale 2D du fluor par les techniques AES et SAM. Les propriétés du cœur et de la sous-surface des LTO-F ont été caractérisées par le couplage de la DRX, du Raman et de la RMN 19F du solide, aucune modification structurelle induite par la fluoration n’a été observée. L’influence de la fluoration de surface sur les performances électrochimiques a été évaluée par le couplage de cyclages galvanostatiques et d’analyses XPS et AES effectuées sur des électrodes ayant cyclées. Les LTO-F montrent une nouvelle réactivité vis-à-vis de l’électrolyte, conduisant à la formation d’une SEI plus fine et plus stable. Enfin, la génération des gaz par les électrodes LTO fluorés a été caractérisée par la GC-MS. Nous avons démontré que la formation de CO2 est réduite par la fluoration de surface. Dans l’ensemble, la stratégie déployée dans cette étude, allant de la synthèse à une caractérisation multiéchelle rigoureuse, propose de nouvelles solutions pour améliorer à la fois la stabilité de la SEI en surface d’électrodes négatives et la stabilité structurale de surface de matériaux d’électrodes positives, pour des batteries Li-ion de plus haute performance
A shift toward greener technologies has been impulsed by the European authorities and tremendous efforts are now engaged to drastically reduce our carbon footprint, by at least for 40 percent by 2030. The development of safe batteries with higher energy density is part of this shift, since this technology is critical for the commercialization and for the rise of electrical mobility and smart energy grid deployment. To do so, new materials need to be developed or existing materials need to be improved to reach higher specific capacities and working electrochemical potentials. The research prospects new electrode materials, new electrolytes and new ways to protect the electrode/electrolyte interphase within the batteries. Indeed, in secondary batteries, the anode/electrolyte interphase plays a key role in the electrochemical performances and life span. Since the classically used liquid organic electrolytes are not stable in the totality of the working potential window of Li-ion batteries, they undergo degradation on cycling of the battery, hence a Solid Electrolyte Interphase (SEI) is formed. This interphase passivates the negative electrodes from the electrolyte and prevents further aging processes, however as this passivation continues in cycling, it also lowers the coulombic efficiency and causes irreversible capacity loss. Knowing this, any modification of the SEI should be performed with parsimony as it could break the balance between the positive and negative aspect for the SEI. By synthetizing a chemisorbed thin fluorinated layer upon anode material, we managed to improve the passivating power of the SEI on TiO2 and Li4Ti5O12 (LTO) anodes, leading to enhanced electrochemical performance. We also determine that very low quantities of fluorine on the active electrode material surface leads to several beneficial effects. We demonstrated that the fluorination brings as well enhancement for positive electrode materials, such as LiNi0.8Co0.15Al0.05O2 (NCA). Indeed, NCA and NMC suffer structural surface instability, leading to self-heating and loss of performance. Improved cyclability is observed for fluorinated NCA electrodes as the fluorination stabilizes the surface structure.Surface fluorination was carried by a process using XeF2, for the first time applied to electrode materials. We aimed to prospect the influence of the surface fluorination on different aspect of a Li-ion battery, from the active material to the electrolyte interphase, thanks to a multi-scale probing approach. The chemical nature of the surface layer on negative and positive electrode materials was described by the mean of the XPS, as well as the fluorine distribution on the surface with both AES and SAM. The bulk and sub-surface properties of fluorinated LTO (LTO-F) were also investigated by coupling XRD, Raman Spectroscopy and NMR 19F, showing no modifications of the crystallographic structure. The influence of the surface fluorination on the electrochemical performance was investigated by galvanostatic cycling and by coupling XPS and SAM on cycled electrodes. We paid a specific attention to the impact of the fluorination on the SEI thickness and stability in charge and discharge. Indeed, LTO-F exhibits a new reactivity toward the electrolyte, leading to a thinner and stabilized SEI. Finally, the gas generation of the LTO-F electrodes has been investigated by Gas Chromatography – Mass Spectrometry (GC-MS), as gassing is known to be a roadblock to the commercialization of LTO. We demonstrated that the CO2 outgassing is reduced by the surface fluorination. Overall, the strategy implemented in this work, from synthesis to thorough characterization, offer new solutions to improve both SEI formed on negative electrode material as well as surface structural stability of positive electrode material, leading to improved Li-ion batteries

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17

Moses, Alvira. "Synthesis of surface active alkanes for cellulose modification". Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/4874.

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119 leaves single sided printed, preliminary pages and numbered pages 1-101. Includes bibliography and a list of tables, figures, schemes and abbreviations. Digitized at 300 dpi (OCR), used Bizhub 250.
Thesis (MSc (Polymer Science))--University of Stellenbosch, 2006.
ENGLISH ABSTRACT: The properties and interactions of cellulose surfaces are of a great technical interest during papermaking and recycling. Sizing, the modification of fiber surfaces, e.g. with the purpose to reduce water penetration into the paper structure, plays an important role in obtaining paper with good printability and water resistance. Water resistance is the key end-property of paper being investigated in this study. Firstly a comparison was made between the degree of surface modification of cellulose by means of anionic, nonionic and reactive surfactants. The amount of surfactant adsorbed by the paperboard was determined and the paper surface evaluated via scanning electron microscopy (SEM). The sizing efficiency of the three industrial surfactants was evaluated in order to establish the surfactant structure best suited for sizing recycled paperboard. This was done via the Cobb test, an industrial method to measure water uptake by paper, and contact angle measurements. The reactive surfactant was found to have the best sizing efficiency and focus shifted to synthesizing selected copolymer surfactants via free radical copolymerization. Two copolymers were synthesized, with maleic anhydride as the polar part in both. Butyl methacrylate and lauryl methacrylate were selected as the hydrophobic parts in the respective copolymer systems. The unavailability of reactivity ratios for the respective copolymer systems led to the use of in situ proton nuclear magnetic resonance spectroscopy CH NMR) for the determination of the co-monomer incorporation in both copolymer systems. Quantitative 13C NMR spectroscopy was also employed in order to establish the co-monomer content of the isolated copolymers obtained during bench-scale (laboratory) experiments. Lastly, a comparison of the degree of surface modification of cellulose was made between that which was achieved with the industrial reactive surfactant and that with the two synthesized polymeric reactive surfactants. The two synthesized polymeric surfactants were found to have a better sizing efficiency than the industrial reactive surfactant, and the maleic anhydride-lauryl methacrylate copolymer system gave the best results.
AFRIKAANSE OPSOMMING: Die eienskappe en interaksies van sellulose-oppervlaktes is van groot tegniese belang gedurende die vervaardiging en hergebruik van papier. Oppervlakte behandeling, die modifikasie van vesel-oppervlaktes bv. met die doel om water indringing in die papierstruktuur te verminder, speel 'n belangrike rol in die daarstel van papier met goeie drukkwaliteit en waterweerstand. Waterweerstand is die sleuteleienskap van papier wat in hierdie werkstuk ondersoek word. Eerstens is daar 'n vergelyking getref tussen die verandering van sellulose-oppervlaktes deur middel van anioniese, nie-ioniese en reaktiewe sepe. Die hoeveelheid seep geabsorbeer deur die papierbord is bepaal en die papier-oppervlak ondersoek deur middel van skandeer-elektronmikroskopie (SEM). Die behandelingsdoeltreffendheid van die drie industriele sepe is ondersoek om vas te stel watter seep die beste struktuur het om hergebruikte papierbord effektief te behandel. Dit is gedoen deur middel van die Cobbtoets, 'n industriele metode om wateropname van papier te meet, asook kontakhoekmetings. Daar is gevind dat die reaktiewe seep die beste behandelingsdoeltreffendheid het en daar is vervolgens gekonsentreer op die bereiding van geselekteerde reaktiewe kopolimeersepe deur middel van vryeradikaalkopolimerisasie. Twee kopolimere is berei, met maleienanhidried as die polere gedeeite van albei. Butielmetakrilaat en laurielmetakrilaat is gekies vir die nie-polere gedeeltes van die onderskeie kopolimeersisteme. Die onbeskikbaarheid van reaktiwiteitsverhoudings vir die onderskeie kopolimeersisteme het gelei tot die gebruik van in situ proton kern magnetiese resonansie spektroskopie eH KMR) vir die bepaling van die ko-monomeer insluiting in beide kopolimeersisteme. Kwantitatiewe koolstofdertienkemmagnetieseresonansie spektroskopie (13C KMR) is ook gebruik om die ko-monomeerinhoud van die geisoleerde kopolimere, verkry tydens laboratoriumeksperimente, te bepaal. Laastens is 'n vergelyking getref tussen die graad van modifikasie van selluloseoppervlaktes deur middel van die industriele reaktiewe seep in vergelyking met die twee bereide polimeriese reaktiewe sepe. Daar is gevind dat die twee gesintetiseerde polimeriese sepe beter behandelingsdoeltreffendheid as die industriele reaktiewe seep het, met die maleienanhidried-laurielmetakrilaat-kopolimeersisteem wat die beste resultaat lewer.

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18

Kepets, Mark Alexander 1978. "Actively conformable aerodynamic surfaces". Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/82226.

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19

Melyukov, Dmitry. "Etude et développement d'une méthode de caractérisation in-situ et à distance de dépôts en couches minces par pyrométrie active laser". Ecole nationale d'ingénieurs (Saint-Etienne), 2011. http://www.theses.fr/2011ENISE004.

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Les matériaux revêtus sont utilisés partout dans l’industrie actuelle. L’objectif principal pour assurer la qualité pendant la fabrication comme pendant l’exploitation est un contrôle des propriétés de ces couches essentiellement son épaisseur mais aussi son homogénéité et son adhésion au substrat. Idéalement, la technique permettant ce contrôle ne doit pas changer l’état de notre couche, c'est-à-dire être non-destructive. Il existe plusieurs méthodes du contrôle non-destructif (CND) comme les ultrasons, les courants Foucault, la radiographie… Dans le cadre de cette thèse on a concentré nos efforts sur la méthode de thermographie active (TA) qui présente, par rapport aux autres technique de CND l’avantage de pouvoir être effectuée à distance, sans contact, rapidement et avec une haute résolution spatiale. On a étudié le cas du chauffage de la surface par un faisceau laser couplé avec les mesures du rayonnement thermique par détecteur infrarouge au centre de la tache laser. Tout d’abord nous avons accompli l’analyse théorique pour mieux comprendre quelles propriétés des couches pouvaient être déterminée par la méthode de TA et sous quelles conditions. Le résultat de cette étude théorique est le développement de méthodes de caractérisation complète de notre couche et particulièrement une méthode de mesure de l’épaisseur indépendamment de toutes autres propriétés (optique, thermique). La partie expérimentale de ce travail a montré le bon fonctionnement de la méthode de mesure de l’épaisseur d’une feuille des matériaux différents (INOX, titane, tungstène et al. ). On a ainsi vérifié la faisabilité de la méthode de mesure de l’épaisseur sans contact (et à distance) et sans calibration (et sans connaître les propriétés du matériau)
Layered materials are used throughout the industry today. The main objective to ensure quality during manufacturing as well as during operation is the control of the properties of these layers mainly its thickness but also its homogeneity and adhesion to the substrate. The most desirable technique is a technique that does not change the state of our film, i. E. Non-destructive. There are several methods of non-destructive testing (NDT) such as ultrasound, eddy current, radiography etc. As part of this thesis we focused our efforts on the active thermography method (TA) which has some advantages over other NDT techniques such as the possibility to put some distance between the test piece and the device, the absence of contact, the speed of the measurements and the high spatial resolution. We studied the case of heating of the surface by a laser beam coupled with measurements of thermal radiation by infrared detectors in the center of the laser spot. First of all we have done theoretical analysis to understand what properties of the layers can be determined by the method of TA under what conditions. As the result of this theoretical study we developed a number of methods for complete characterization of the layer and especially the methods for measuring the thickness independently of all other properties (optical, thermal). The experimental part of this work has shown the proper functioning of the method for measuring the thickness of a sheet of different materials (stainless steel, titanium, tungsten et al. ). By this way it was verified the feasibility of the method for measuring the layer thickness without contact (and at a distance) and without calibration (and without knowing the material)

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20

Myers, Travis R. (Travis Ray). "Active hyperspectral imaging of chemicals on surfaces". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/112385.

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Thesis: S.M. in Materials Science, Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2014.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 90-92).
Active hyperspectral imaging (HSI) is a promising technique for the detection of chemicals at standoff distances. In active HSI, a target is illuminated by a laser source at many different wavelengths and a camera obtains an image of the illuminated scene at each wavelength. In this research, the feasibility of hyperspectral imaging for the detection of particles on surfaces was demonstrated using potassium chlorate particles on car panels at distances of 5 m, 10 m, and 20 m. Using the Adaptive Cosine Estimation (ACE) algorithm which compares the observed reflectance spectra to a reference spectrum, potassium chlorate fingerprints are easily visible at many different sample angles. However, in general, there is a large amount of variation in the shape and magnitude of spectra in a hyperspectral image that depend on factors such as particle size, viewing geometry, and surface reflectivity. Thus, Mie Theory calculations are performed on simulated materials and combined with information from sources such as Hapke [4], [20] to give qualitative insight into the expected shape and magnitude of reflectance spectra from sparse particles on a surface. The shape of the spectra depends on whether the particles are strongly absorbing or weakly absorbing. Strongly absorbing particles tend to have reflectance maxima near the resonant frequency, whereas weakly absorbing particles tend to have reflectance minima. For highly reflective substrates, the reflectance decreases sharply as the sample angle increases and becomes dominated by backward scattering from the particle which has a flatter spectrum around the Christiansen frequency, the frequency at which the refractive index of the particle is closest to one. The double interaction model, which uses Mie Theory to calculate the contributions to the reflectance along two different light paths, is used to accurately account for how the shape and magnitude of the reflectance spectra of sodium chlorate particles on gold and silica surfaces changes as a function of sample angle and laser angle. A method for approximating the mean particle size based on the location of the peak near the Christiansen frequency is derived. This method, when applied to the sodium chlorate sample, yields a result for the mean particle diameter that is approximately half of the value determined using a microscope. The Hapke Isotropic Multiple Scattering Approximation (IMSA), combined with Mie Theory, is used to give qualitative insight into the expected shape and magnitude of reflectance spectra from bulk powders. Compared with the reflectance spectra from sparse particles, the spectra from bulk powders are much simpler and less dependent on the viewing geometry. The Hapke IMSA model is able to accurately account for the observed changes in the reflectance from bulk sodium chlorate powder at multiple sample angles and laser angles. A final scenario of interest is thin films on rough or porous surfaces. Using a model that takes into account diffusely reflected and specularly reflected light, the observed reflectance spectra from diethyl phthalate (DEP) on a brick is fitted to a high degree of accuracy. This suggests a promising method for using hyperspectral imaging to determine the thickness of liquids on porous surfaces. Finally, the issue of speckle in hyperspectral imaging was examined using simulations based on Fourier optics and information from sources such as Goodman [6], [17]. Speckle is a limiting factor in hyperspectral imaging because it is noise that scales with the signal, and thus cannot be eliminated by increasing the signal strength. Equations from various sources are presented that describe the reduction in speckle contrast for spatial, spectral, polarization, temporal, and angular averaging. Original equations for the reduction in contrast for spectral and angular averaging are derived.
by Travis R. Myers.
S.M. in Materials Science

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21

Pawar, Amita A. "Smart Material Actuators For Active Tactile Surfaces". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1338400866.

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22

Chmiel, Malgorzata. "Traitement de données géophysiques en réseaux denses en configuration sismique passive et active". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAU009/document.

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En géophysique, les réseaux denses améliorent la caractérisation spatiale et fréquentielle des différents types d’ondes dans le milieu. Bien entendu, l’acquisition en surface est sujette aux ondes de surface qui sont très fortes. Les ondes de surface ont un fort impact sur les données géophysiques acquises au niveau du sol. Elles peuvent être considérées comme du bruit et être sujettes à la suppression puisqu’elles cachent l’information de sous-surface. Cependant, elles peuvent être utiles pour l’imagerie de proche surface si elles sont convenablement récupérées.Dans tous les cas, leur caractérisation est cruciale en géophysique d’exploration active et passive. Dans la surveillance microsismique passive, le bruit de surface ambiant est composé d’ondes de surface. L’objectif principal de la surveillance passive est de minimiser l’impact des ondes de surface sur les données microsismiques. Le fort bruit de surface diminue la sensibilité etl’efficacité des méthodes de détection et de localisation. De plus, les méthodes actuelles de localisation et de détection nécessitent généralement la connaissance d’informations telles qu’un un modèle de vitesse ou un modèle d’événement. Dans la sismique active, de fortes ondes de surface sont générés par des sources actives. Les stratégies actuelles de traitement sont généralement basées sur une sélection manuelle des ondes de surface afin de choisir lesquelles garder. Il s’agit là d’une tâche complexe, coûteuse et sujette à interprétation. Cependant, cette tâche est nécessaire pour l’imagerie de proche-surface et de sous-surface. Les ondes de surface peuvent être particulièrement difficiles à récupérer dans des acquisitions clairsemées.Nous proposons d’appliquer les techniques d’interférométrie et de formation de voies (telles que le Matched Field Processing) dans le contexte des réseaux denses. Une densité de traces importante ouvre de nouvelles possibilités dans les traitements géophysiques, qu’ils soient actifs ou passifs. Nous montrons que le bruit ambiant peut être utilisé dans le traitement microsismique pour extraire des informations importantes sur les propriétés du milieu. De plus, nous développons une approche de débruitage qui permet de supprimer les sources de bruit à la surface et détecter les événements microsismiques. Nous proposons également une méthode automatique de détection et de localisation qui se base sur une quantité minimale d’information préalable qui permet de récupérer la distribution des hétérogénéités du réservoir, dans le voisinage du puits. En ce qui concerne la sismique active, nous proposons une approche interférométrique et automatique de caractérisation des ondes de surface. Nous récupérons les noyaux de sensibilité de phase des ondes de surface entre deux points quelconques de l’acquisition. Ces noyaux de sensibilité sont par conséquent utilisés pour obtenir les courbes de dispersion multimodales. Ces courbes de dispersion permettent la séparation des différents modes des ondes de surface, et fournissent l’information de proche surface suite à une simple inversion.Le réseau dense permet l’amélioration des méthodes présentées ci-dessus: elle permet des applications alternatives et innovantes dans le traitement du signal géophysique
In geophysics, spatially dense arrays enhance the spatial and frequential characterization of the various waves propagating in the medium. Of course, surface array is subject to strong surface waves. Surface waves highly impact the processing of geophysical data acquired at ground level. They can be considered as noise and subject to suppression as they mask sub-surface information.However, they can be useful for near-surface imaging if they are well retrieved. In any case, their characterization is crucial in active and passive exploration geophysics. In passive microseismic monitoring, ambient surface noise consists of surface waves. The main goal of passive monitoring is to minimize the impact of surface waves on the actual microseismic data. The strong ambient surface noise lowers the sensitivity and the efficiency ofdetection and location methods. Moreover, current location and detection methods usually require strong a priori information (e.g., a velocity model or a template).Active sources generate strong surface waves. In active seismic, current processing strategies often consist in manually picking surface wave arrivals in order to use or remove them. This is often a complex, time consuming, and an ambiguous task. However, it is needed for near- and sub-surface imaging. Surface waves can be particularly difficult to retrieve in sparse arrays. We propose to apply the techniques of interferometry and beamforming (Matched Field Processing in particular) in the context of dense arrays. High trace density opens new possibilities in geophysical processing in both passive and active surveys. We show that the ambient noise can be explored in the case of microseismic monitoring to extract important information about the medium properties. Moreover, we develop a denoising approach to remove the noise sources at the surface and detect the microseismic event. Furthermore, we propose an automatic detection and location method with a minimum a priori information to retrieve the distribution of heterogeneities in the reservoir, in the well vicinity.In active survey, we propose an interferometric, automatic approach to characterize the surface waves. We retrieve phase-sensitivity kernels of surface waves between any two points of the acquisition. These kernels are consequently used to obtain multi-mode dispersion curves. These dispersion curves make it possible to separate different modes of surface waves and provide near-surface information if inverted.The above presented methodologies benefit from spatially dense arrays.Dense arrays of sources or receivers enable alternative, innovative applications in geophysical processing

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Gordon, Alexander David. "In Situ Studies of Promoted Catalytic Surfaces and Redox Active Mineral Surfaces". Diss., Temple University Libraries, 2011. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/209132.

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Chemistry
Ph.D.
In this dissertation the in situ technique, attenuated total reflection-Fourier transform infrared spectroscopy, will be utilized to probe reaction chemistry on two sets of surfaces; the first, a silicon-copper alloy surface where copper acts as a catalyst in the synthesis of methylchlorosilanes, and the second, a redox active iron-sulfur surface. Spectroscopic information obtained in situ will be combined with kinetic batch reaction results to elucidate details of the reaction mechanism that gives information regarding product formation in real time under real experimental conditions, without the need for modifying the experimental conditions to fit the analysis as is the case in traditional surface science techniques.
Temple University--Theses

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24

Barthes, Julien. "Revêtements surfaciques à base de polymères et de composants naturels : applications à la mise au point de surfaces mécano-sensibles et de substrats cellulaires nourriciers". Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAE018/document.

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Cette thèse s’est articulée autour de l’élaboration de revêtements surfaciques à base de polymères et de composants naturels. Dans un premier projet, des surfaces mécano-sensibles pour des applications de libération de molécules bioactives ont été élaborées. Des films de multicouches polyélectrolytes constitués d'une strate « réservoir » permettant le chargement d’une molécule bioactive, le paclitaxel, et d'une strate « barrière » mécano-sensible recouvrant ce réservoir et confinant le paclitaxel ont été élaborés. Lors de la mise sous étirement du film, la barrière est rendue perméable vis-à-vis d'une enzyme présente dans le surnageant. Cette enzyme induit ensuite la dégradation enzymatique du « réservoir » et la libération du paclitaxel. Dans un second projet, des substrats cellulaires nourriciers ont été réalisés à partir de films minces de gélatine réticulés mimant la matrice extracellulaire. Ces films peuvent être chargés: 1) en facteurs de croissance, ce qui permet de s'affranchir ensuite de l'ajout de ces molécules dans le milieu de culture; 2) en nanoparticules afin de moduler les propriétés mécaniques des films; 3) en agents antimicrobiens pour assurer une stérilité de la culture cellulaire. Ainsi, ces substrats aux propriétés biochimiques et biophysiques modulables permettent un contrôle précis du microenvironnement cellulaire
This PhD work is about designing surface coatings with polymers and natural compounds. In the first project, mechanosensitive surfaces have been developed for drug release applications. Polyelectrolyte multilayer films have been designed with i) one reservoir strata for the loading of a bioactive molecule, paclitaxel, and ii) one mechanosensitive barrier strata on top of the reservoir to confine the molecule. When a mechanical stretch is applied on the structure, the barrier becomes permeable and enables the diffusion of an enzyme within the film.This enzyme degrades the reservoir strata and triggers the release of paclitaxel. In a second project, ECM-mimicking feeder substrate has been developed with crosslinked gelatin thin films. These films can be loaded with: i) growth factors to prevent any further addition of these compounds in the culture medium; ii) nanoparticles to modulate mechanical properties of the substrate; iii) antimicrobial agents to ensure sterility during cell culture experiments. Finally, these substrates have some biochemical and biophysical tunable properties that enable the precise control of cell microenvironment

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25

Kacem, Imen. "Textiles à activité biologique via le greffage par plasma et l’immobilisation de molécules bioactives". Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10020/document.

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L’intérêt des implants médicaux ne cesse de grandir et leur utilisation tend à s’étendre aux différents domaines de la chirurgie, en partie grâce à l’émergence de nouvelles techniques de modification de surface. Ainsi il est possible d’améliorer les propriétés des biomatériaux en vue d’une meilleure intégration dans les tissus vivants et prévenir les diverses complications liées à leur utilisation. Ceci permet à la fois de répondre aux attentes des chirurgiens, d’améliorer les conditions de guérison des patients suite à l’intervention, voire même d’apporter une activité thérapeutique à long terme au biomatériau en évitant la rechute, la thrombose, la restenose ou l’infection. C’est dans ce contexte que nous avons cherché à fonctionnaliser la surface de textiles en polyester (polyéthylène téréphtalate), matière très largement utilisée dans le domaine médical, par des molécules bioactives connues par leurs propriétés antibactérienne ou anti-thrombotique: le lysozyme, la gentamicine et l’héparine. L’idée développée dans ce travail de thèse fut de fixer dans un premier temps des fonctions acide carboxylique (-COOH) jouant le rôle d’«ancre» pour la fixation ultérieure des trois principes actifs. La première étape a donc consisté à greffer l’acide polyacrylique (PAA) par copolymérisation greffante assistée par traitement plasma froid, suivie dans un second temps, de la fixation des trois principes actifs, par liaisons physiques (ioniques) et/ou covalentes. L’étude a d’abord porté sur l’optimisation des paramètres de ces deux étapes du traitement via une investigation systématique et un plan d’expériences. Des techniques de caractérisations telles que la spectrophotométrie UV, l’analyse infrarouge IRTF, l’analyse thermique ATG, l’analyse par spectrométrie photoélectronique XPS, la goniométrie, la microscopie électronique à balayage MEB et des essais mécaniques ont montré l’évolution de la composition de la surface et de propriétés mécaniques des textiles au fil des différentes étapes. Des études biologiques par des tests de vitalité cellulaire, d’adhésion plaquettaire et de coagulation ainsi que différentes études microbiologiques ont pu montrer selon les différentes voies de modification choisies l’obtention de supports fonctionnalisés biocompatibles à efficacité intéressante pour des applications biomédicales
The interest in medical implants increases and their use spreads to different surgical domains partially thanks to the new techniques of surface modification. Therefore it is possible to improve the biomaterials properties in order to solve the problems liked with their integration in the living tissues and thereby to prevent the various complications related to their use. This approach allows to respond to the surgeons expectations, to improve the curing process of the patients and even to involve long term therapeutic activities to the biomaterial, thus preventing the release of the disease (such as thrombosis, restenosis, infection). In this context, we have attempted the functionalization of the surface of a polyester fabric (polyethylene terephtalate), widely used in medical field, by three bioactive molecules: lysozyme, gentamicin and heparin known for their antimicrobial or anti thrombotic properties. The concept was to graft polyacrylic acid (PAA) by graft polymerization induced by cold plasma technique, followed by the immobilization of the above mentioned molecules through physical and covalent links. We studied all the experimental parameters involved in the different processes and followed the properties of the obtained materials through the appropriate characterizations techniques, such as spectrophotometry UV, Infrared analysis IRTF, Thermogravimetric analysis (TGA), X-ray Photoelectron Spectroscopy (XPS), goniometry, scanning electron microscope (SEM), and mechanical tests. Finally, biological studies such as cell vitality tests, platelets adhesion test and coagulation test in addition with various microbiological essays showed the evolution of the biological properties of the materials, depending on the path of their modification resulted in the development of a novel, biocompatible functionalized supports family with very interesting and attractive efficacy for biomedical applications

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26

Belliart, Michel. "Actions de groupes de Lie sur les variétés compactes". Valenciennes, 1995. https://ged.uphf.fr/nuxeo/site/esupversions/9806b24c-e64d-4e28-b75a-6d3de2b5eb3a.

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Cette thèse est en deux parties. Dans la première partie, on énonce, justifie et montre partiellement la conjecture suivante : L'action localement libre de codimension 1, au moins deux fois continument différentiable et préservant le volume d'un groupe de Lie non-unimodulaire sur une variété compacte est conjuguée dans sa classe de différentiabilité à une action homogène. On fournit également des exemples de groupes auxquels ce résultat s'applique. Dans la seconde partie, on répond complètement au problème suivant, posé par J. F. Plante en 1986 : A quelles conditions un groupe de Lie connexe donné peut-il agir continument et sans point fixe global sur une surface compacte donnée ? On en déduit une réponse à trois questions posées par Plante dans le même domaine. Ces deux résultats constituent la partie originale de la thèse. Ils sont précédés de deux survols, l'un de la théorie de Lie, l'autre de celle des surfaces, et la seconde partie est suivie d'une copie du dernier chapitre de la thèse de Mostow, ce qui en facilite la lecture.

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27

Wahlgren, Marie. "Adsorption of proteins and interactions with surfactants at the solid/liquid interface". [Lund : Dept. of Food Technology, Lund University], 1992. http://books.google.com/books?id=zfxqAAAAMAAJ.

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28

Katuri, Jaideep. "Guiding active particles through surface interactions". Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/663989.

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Living organisms and systems are continually converting energy, either internally stored or transduced from their surroundings, into motion. This activity and the resulting self-propulsion constantly push these biological systems out of thermal equilibrium. A number of exotic phenomenon result from the intrinsic non-equilibrium nature of these living systems, that are not accessible in a system at thermal equilibrium. In recent years, these ubiquitous non-equilibrium systems have come to be classified as active matter. Active matter, by definition, refers to systems composed of active units, each capable of converting ambient or stored energy into systematic movement. Examples range from the sub-micrometer scale, with microtubules associated with motor proteins in the cytoplasm, to the micrometer length scales of swimming bacteria, and the meter-length scales of greater familiarity, such as that of fish and birds. There are two common themes that run through all these active matter systems. The first is the emergence of correlated collective phenomenon through particle-particle interactions as exemplified in flocking of birds, swarming of bacteria and crystallization of self-propelled particles. And the second is the ability of the active units to interact with their surroundings through self-propulsion. Common examples of this include chemotaxis and rheotaxis, observed in many biological systems. In this thesis, I have focussed on studying the ability of artificial active matter systems to respond to their local environment. As a model active matter system, we use colloidal active particles, that propel due to self-diffusiophoresis. These particles coated with two different materials on each half are referred to as Janus particles. In a solution of H2O2, one of the sides has catalytic properties (Pt), while the other half remains inert (SiO2). This creates a concentration gradient of the reaction product along the surface of the particle and induces a phoretic slip, which propels the particle. We study the dynamics of these self-phoretic particles close to solid surfaces. The particles interact with their surroundings via hydrodynamic and phoretic effects and we observe that when confined closed to a surface, a strong alignment interaction comes into play. This effect can be used to guide micron sized active particles along predetermined pathways. We then exploit this alignment interaction to design micropatterned ratchets capable of generating a strong directional flow of active particles. A different geometry of the same system can also be used to accumulate active particles in confined areas. Finally, we study the influence of an applied external shear flow on the dynamics of active particles near surfaces. We find that a strong directional response emerges for the active particles in the direction perpendicular to the flow direction leading to the cross-stream migration of active particles. This response is dependent on the applied shear flow and the propulsion velocity of the particle, potentially opening up a possibility to sort particles of different activities based on their response to shear flows. Overall, our results indicate that active particles can have a strong directional response in certain environments allowing us to engineer ways of guiding them.
Los organismos y sistemas vivos convierten energía almacenada internamente o derivada de sus alrededores en movimiento de forma continua. Esta actividad puede causar una constante auto-propulsión que lleva a estos sistemas a un estado fuera de equilibrio térmico. Gracias a esto, aparecen un gran número de fenómenos exóticos que no son accesibles para un sistema que se encuentra en equilibrio térmico. En los últimos años se ha clasificado a estos sistemas de no equilibro como “material activa”. La materia activa, por definición, incluye los sistemas compuestos de unidades activas, cada una de ellas capaz de convertir la energía almacenada o del entorno en movimiento sistemático. Existen varios ejemplos que van desde la escala sub-micrométrica, donde podemos encontrar a los microtúbulos asociados a proteínas motoras en el citoplasma, a las grandes escalas, donde se encuentran sistemas más familiares como peces o pájaros, pasando por la escala micrométrica, donde nadan las bacterias. Podemos diferenciar dos temas principales que se manifiestan en todos estos sistemas de materia activa. El primero es la aparición de fenómenos colectivos correlacionados a través de interacciones partícula-partícula, como ocurre en bandadas de pájaros, enjambres bacterianos y la cristalización de partículas auto-propulsadas. El segundo es la capacidad de estas unidades activas de interaccionar con sus alrededores a través del fenómeno de la auto-propulsión, por ejemplo, a través de quimiotaxia o reotaxia, como se puede observar en muchos sistemas biológicos y que ya han sido reportados en varios estudios. En esta tesis, me he enfocado en el estudio de este último tema principal: la interacción de partículas activas con su entorno local. Como modelo de sistema de materia activa, usamos partículas activas coloidales que se propulsan gracias al fenómeno de auto-difusioforesis. Estas partículas están recubiertas por dos materiales diferentes en cada una de sus caras, y son comúnmente llamadas “partículas Janus”. Una de sus caras está recubierta con Pt, material que cataliza la descomposición de H2O2, mientras que la otra cara está recubierta de un material inerte (SiO2). En una solución de H2O2, la reacción que ocurre en la parte catalítica produce un gradiente de concentración de producto a lo largo de la superficie de la partícula e induce un deslizamiento forético que la propulsa. En esta tesis se ha estudiado la dinámica de estas partículas "autoforéticas" cerca de superficies sólidas. De manera natural, las partículas interaccionan con su alrededor debido a los efectos foréticos e hidrodinámicos. Cuando estas partículas se hayan confinadas cerca de una superficie, observamos que se origina en ellas una fuerte interacción de alineamiento. A partir de ello, consideramos interesante diseñar ratchets micro estampados capaces de generar un flujo direccional de partículas activas. Por otra parte, estudiamos la influencia de aplicar un flujo de cizalla externo en la dinámica de las partículas activas cerca de superficies. A consecuencia del flujo externo, encontramos que en el sistema emerge una respuesta fuertemente direccional para las partículas activas en la dirección perpendicular al flujo provocando una migración "cross-stream" de partículas activas.

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29

Mitran, Marcel. "Active surface reconstruction from optical flow". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33980.

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This thesis describes the design and implementation of an active surface reconstruction algorithm for two-frame image sequences. The objective is to build a system that uses a passive sensor and an active viewer to accumulate information for disambiguating the depth sampling process involved in surface reconstruction. The viewer is considered to be restricted to a short baseline. Several ideas from the fields of optical flow, stereovision, and shape from motion will be drawn from and modified in the context of an active vision system.
The thesis begins by examining the optical flow estimation problem. Several algorithms are compared under the novel heading of maximal estimation theory. Each algorithm is decomposed into three parts: pixel-estimation, sub-pixel estimation and confidence measurement. The components are compared separately. A flow algorithm is then obtained by combining different components.
A Bayesian framework is adopted to provide a simple approach for propagating information in a bottom-up fashion in the system. This will also be used for combining information both temporally and spatially in the context of a Kalman filtering scheme.
The last part of this thesis examines how an active component can be integrated into the system to provide quicker convergence to the depth estimate. This approach is based on statistical grouping of image gradient features.
Synthetic and real experimental results are generated in each section. These results support ideas presented in the thesis, and suggest a basis for further research.

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30

Cipolla, Roberto. "Active visual inference of surface shape". Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293392.

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31

Ye, Jian. "Elastic interaction models for active contours and surfaces /". View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?MATH%202005%20YE.

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32

Alvino, Christopher Vincent. "Multiscale Active Contour Methods in Computer Vision with Applications in Tomography". Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6896.

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Most applications in computer vision suffer from two major difficulties. The first is they are notoriously ridden with sub-optimal local minima. The second is that they typically require high computational cost to be solved robustly. The reason for these two drawbacks is that most problems in computer vision, even when well-defined, typically require finding a solution in a very large high-dimensional space. It is for these two reasons that multiscale methods are particularly well-suited to problems in computer vision. Multiscale methods, by way of looking at the coarse scale nature of a problem before considering the fine scale nature, often have the ability to avoid sub-optimal local minima and obtain a more globally optimal solution. In addition, multiscale methods typically enjoy reduced computational cost. This thesis applies novel multiscale active contour methods to several problems in computer vision, especially in simultaneous segmentation and reconstruction of tomography images. In addition, novel multiscale methods are applied to contour registration using minimal surfaces and to the computation of non-linear rotationally invariant optical flow. Finally, a methodology for fast robust image segmentation is presented that relies on a lower dimensional image basis derived from an image scale space. The specific advantages of using multiscale methods in each of these problems is highlighted in the various simulations throughout the thesis, particularly their ability to avoid sub-optimal local minima and their ability to solve the problems at a lower overall computational cost.

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33

Potter, Rory. "Derived categories of surfaces and group actions". Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/19643/.

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This thesis focuses on two distinct projects on the bounded derived category of coherent sheaves of surfaces and group actions from different directions. The first project studies bielliptic surfaces, which arise as quotients of products of elliptic curves by a finite group acting freely. We prove a structure theorem describing the group of exact autoequivalences of the bounded derived category of coherent sheaves on a bielliptic surface over C. We also list the generators of the group in some cases. The second project studies semi-orthogonal decompositions of the bounded equivariant derived category of a surface S with an effective action of a finite abelian group G. These semi-orthogonal decompositions are constructed by studying the geometry of the quotient stack [S / G]. We produce new examples of semi-orthogonal decompositions of the equivariant derived category of surfaces with a finite abelian group action. We give a new proof of the Derived McKay correspondence in dimension 2. Using this, we construct semi-orthogonal decompositions of the equivariant derived category of C^2 with an effective action of the Dihedral group D_2n. Moreover, we show that these semi-orthogonal decompositions satisfy a conjecture of Polishchuk and Van den Bergh.

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34

Kabal, David. "Packaging of surface active optoelectronic device arrays". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ44015.pdf.

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35

Kabal, David. "Packaging of surface active optoelectronic device arrays". Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20503.

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Requirements of electronic systems are increasing, as the applications for these systems become more complex and require more bandwidth. Optical interconnection can help satisfy these system requirements. In order for an optical interconnect to be successful, system design must satisfy new demands on the packaging of the optically interconnected devices, different from those encountered in packaging electronic interconnects.
This thesis addresses the issues faced in designing the packaging for a two-dimensional array of surface active optoelectronic devices, within the framework of a free-space optically interconnected backplane. Two demonstrator systems' packaging are presented, as well as a general discussion of the issues and constraints involved in the design, assembly and testing of this packaging. These issues include connectivity, bandwidth, thermal management, optomechanical interfacing and space constraints.
The particular optoelectronic devices examined are Quantum Confined Stark Effect (QCSE) modulators and detectors. The impact of temperature sensitivity on these particular devices is examined, and a technique for optimizing their performance at a specific temperature is presented. As a thermal diagnostic aid, as well as a thermal management tool, the design and characterization of an array of temperature sensors integrated into an optoelectronic device array is presented.

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36

Bolin, Maria. "Conjugated Polymer Surface Switches for Active Control". Doctoral thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-71361.

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Conjugated polymers have been found useful in a wide range of applications such as sensors, electrochemical transistors, solar cells, and printed electronics due to their mechanical, optical and electronic properties. An amazing research field has grown during the last three decades since the discovery of conducting polymers in 1976. Since the materials can be made from solutions, different processing methods such as spin coating and vapor phase polymerization can be used to coat a huge variety of substrates. The choice of method depends mainly on monomer solubility and kind of substrate to be coated. During the synthesis the polymers can be chemically modified to tailor their functionalities. Due to this variability in materials and the processability, electronics can be achieved on unconventional substrates such as flexible plastic foils and cell culturing dishes. As a contrast to inorganic, usually metallic materials, conducting polymers are built up from organic compounds in a molecular structure with soft mechanical properties that have shown to be a benefit in combination with biology, ranging from interactions with cells to interactions with advanced biological species such as tissues. This combination of research fields and the possible applications are merged within the field of organic bioelectronics. The primary purpose of this thesis is to give a background to organic electronics in general and how electrochemical devices can be processed and developed for biological applications in particular. An organic electronic surface switch is introduced to control cell adhesion and proliferation as well as an electrochemical transistor to spatially tune the cell adhesion along an electrochemical gradient. To mimic a more natural cell environment a three dimensional fiber substrate was used to design an electronically active matrix to promote nerve cell adhesion and communication. By combining standard microfabrication techniques and conjugated polymers desired patterns of electroactive polymer were created to enable active regulation of cell populations and their extracellular environment at high spatial resolution. Finally, a brief look into future challenges will also be presented.

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37

Kirby, Laura Rebecca. "Surface Water Impacts from Active Underground Mining". Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23290.

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High extraction mining techniques have produced the need to mitigate and understand ground movements associated with this technology. Tools such as the Surface Deformation Prediction System (SDPS) facilitate sound scientific decision making in the industry and has continually improved since its inception in 1987. The capabilities of SDPS have expanded on an as-needed basis. Currently, the regulatory climate has emphasized the need to understand the impact of underground mining on surface waters, physically and chemically.

The SDPS program is used to conduct an analysis of ground movements to assess optimal barrier pillar size for stream protection. Typical analytical and empirical methods used in mine planning were compared against SDPS methods to ensure the validity and advantage to the use of SDPS for this purpose.

Finally, underground mining effects on stream chemistry and health were explored by studying the heavily mined and industrialized watershed of Dumps Creek located in Russell County, Virginia. This watershed has been identified as being impaired since the Virginia 303(d) List of Impaired Waters was created in 1994. Currently, there are two pumps staged in the headwaters region of Dumps Creek that help to maintain water levels in an inactive underground mine. The pumping is necessary to control methane levels that rising water could force into an active underground mine that lies stratigraphically above the inactive mine. Water is pumped on an as-needed basis and discharges directly into Dumps Creek. Historic measurements of stream conductivity and benthic health scores were compared to assess whether a correlation exists between the two measurements. These measurements were compared based on regulatory decisions that emphasized that conductivity is a direct indicator of stream health in all watersheds.

Scientific contributions associated with this research include: Further developments in the use of SDPS programming in order to account for stream protection on a case by case basis for both mine panel and surface water protection by optimizing barrier pillar size in relation to a nearby stream; the analysis of available and currently obtained water chemistry data in a mining impacted watershed in attempt to further research to appropriately characterize and mitigate specific problems in order to improve stream health; and, assessment of the complexity of water chemistry impacts from underground mining as related to stream health indicators in different chemically dominated watersheds.

Master of Science

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38

Mobbs, Tamara Leah. "Effects of four soil surfactants on four soil-water properties in sand and silt loam". Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Thesis/Spring2010/t_mobbs_050110.pdf.

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Thesis (M.S. in biological and agricultural engineering)--Washington State University, May 2010.
Title from PDF title page (viewed on June 23, 2010). "Department of Biological Systems Engineering." Includes bibliographical references (p. 16-22).

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39

Mendoza, Alvaro. "The synthesis and characterization of novel surfactants". Laramie, Wyo. : University of Wyoming, 2006. http://proquest.umi.com/pqdweb?did=1296090131&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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40

Jose, Robin. "Synthesis and characterization of novel amphiphiles". Laramie, Wyo. : University of Wyoming, 2006. http://proquest.umi.com/pqdweb?did=1296090121&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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41

Topp, Kathryn A. "Cationic oligomeric surfactants novel synthesis and characterization /". Connect to full text, 2006. http://hdl.handle.net/2123/1728.

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Thesis (Ph. D.)--School of Chemistry, Faculty of Science, University of Sydney, 2006.
Title from title screen (viewed 13 January 2009). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Chemistry, Faculty of Science. Includes bibliographical references. Also available in print form.

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42

Stellner, Kevin Lance. "Precipitation of surfactants and surfactant mixtures in aqueous solutions /". Full-text version available from OU Domain via ProQuest Digital Dissertations, 1987.

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43

Cahill, B. M. "Substrate integrated ferrite phase shifters and active frequency selective surfaces". Thesis, University of Kent, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250325.

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44

Lazarus, Kenneth B. "Multivariable high-authority control of plate-like active lifting surfaces". Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/13171.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1992.
Title as it appears in the M.I.T. Graduate List, June 1992: High-authority multivariable control of strain actuated plate-like active lifting surfaces.
Includes bibliographical references (leaves 162-169).
by Kenneth Brett Lazarus.
Ph.D.

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45

Guisser, Latifa. "Systeme de vision active tridimensionnelle a parametrisation directe des surfaces". Toulouse 3, 1987. http://www.theses.fr/1987TOU30092.

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Le systeme de vision 3d propose utilise la projection d'une grille sur la surface des objets. Cette grille est extraite comme un reseau de courbes par un algorithme de suivi. La grille image est alors reconstituee et la partition en composantes connexes liees aux discontinuites presentes dans la scene est directement obtenue. L'etude de la correspondance entre la grille image et la grille origine a conduit a la definition des criteres severes prenant en compte la relation de voisinage entre les noeuds. L'algorithme propose assure une correspondance sans ambigueite. Les courbes de la grille 3d sont alors obtenues par triangulation. L'aspect geometrique au voisinage des noeuds est deduit du calcul des courbures principales. Le systeme propose permet d'obtenir les donnees 3d d'un objet volumique et de calculer simplement les parametres des formes tridimensionnelles

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46

Hurth, Cédric M. "Scanning probe microscopy studies of active enzymes at solid surfaces". Bordeaux 1, 2005. http://www.theses.fr/2005BOR13106.

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Plusieurs enzymes sont étudiées différentes techniques de microscopies à champ proche afin d'extraire des propriétés mécaniques, électrochimiques et électriques locales. Tout d'abord, la 3-phosphoglycérate kinase de levure (PGK) est étudiée en Microscopie à Force Atomique (MFA) de à la fois ex situ et in situ en mode dynamique par comparaison au mode statique (Contact). Conjointement, l'activité enzymatique de l'enzyme immobilisé est mesurée par spectrophotométrie UV visible et comparée aux constantes connues en solution. Ensuite, la glucose oxydase est étudié par Microscopie Electrochimique à Balayage (SECM) de façon à extraire les constantes catalytiques hétérogènes pour divers supports solides et à caractériser l'éventuelle dépendance de l'activité enzymatique avec un champ électrique continu externe. Une étude critique de la stratégie choisie est présentée avant de se concentrer sur la décomposition catalytique du peroxyde d'hydrogène par la catalase et des nanoparticules de platine liées à une surface solide isolante. Cette étude permet d'introduire une stratégie alternative plus appropriée à l'étude de la dépendance avec le champ électrique continu externe. Enfin, une nouvelle technique, la Microscopie Electrochimique de Potentiel à Balayage (SECPM), est étudiée d'un point de vue essentiellement d'instrumentation car elle se propose prochainement de cartographier le potentiel de surface d'un enzyme alors qu'il réalise son acte catalytique. Plusieurs modifications visant à réduire l'influence perturbatrice des procédés faradiques dus à la présence d'oxygène dissous et de protons en solutions aqueuses non tamponnées sont introduites.

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47

Guisser, Latifa. "Système de vision active tridimensionnelle à paramétrisation directe des surfaces". Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376056785.

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48

Qu, Zheng. "Biologically active assemblies that attenuate thrombosis on blood-contacting surfaces". Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/50119.

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All artificial organ systems and medical devices that operate in direct contact with blood elicit activation of coagulation and platelets, and their long-term use often necessitates antithrombotic therapies that carry significant cost and bleeding risk. Thrombomodulin (TM) is a major endogenous inhibitor of blood coagulation localized on the endothelial cell surface. The overall objective of this research is to develop clinically durable synthetic materials by incorporating TM as a solid-supported film to actively and sustainably attenuate thrombus formation at the blood-contacting interface. During the course of this research, we developed site-specific approaches to covalently attach TM on the luminal surface of commercial vascular grafts using bioorthogonal chemistry that was compatible with ethylene oxide sterilization. Notably, we demonstrated the superior efficacy of TM to reduce platelet deposition compared with commercial heparin modified grafts using a non-human primate model of acute graft thrombosis. Finally, we optimized a novel reversible chemistry to rapidly and repeatedly regenerate immobilized TM, with the potential to significantly extend the lifetime of biologically active films.

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49

Randhawa, Sukanya. "Active control of surface plasmons in hybrid nanostructures". Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/124095.

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Plasmonics nanostructures are becoming remarkably important as tools towards manipulating photons at the nanoscale. They are poised to revolutionize a wide range of applications ranging from integrated optical circuits, photovoltaics, and biosensing. They enable miniaturization of optical components beyond the "diffraction limit'' as they convert optical radiation into highly confined electromagnetic near-fields in the vicinity of subwavelength metallic structures due to excitation of surface plasmons (SPs). These strong electromagnetic fields generated at the plasmonic "hot spots'' raise exciting prospects in terms of driving nonlinear effects in active media. The area of active plasmonics aims at the modulation of SPs supported at the interface of a metal and a nonlinear material by an external control signal. The nonlinear material changes its refractive index under an applied control signal, thereby resulting in an overall altered plasmonic response. Such hybrid nanostructures also allow for the creation of new kinds of hybrid states. This not only provides tools for designing active plasmonic devices, but is also a means of re-examining existing conventional rules of light-matter interactions. Therefore, the need for studying such hybrid plasmonic nanostructures both theoretically and experimentally cannot be understated. The present work seeks to advance and study the control of SPs excited in hybrid systems combining active materials and nanometallics, by an external optical signal or an applied voltage. Different types of plasmonic geometries have been explored via modeling tools such as frequency domain methods, and further investigated experimentally using both near-field and far field techniques such as scanning near field optical microscopy and leakage radiation microscopy respectively. First, passive SP elements were studied, such as the dielectric plasmonic mirrors that demonstrate the ability of gratings made of dielectric ridges placed on top of flat metal layers to open gaps in the dispersion relation of surface plasmon polaritons (SPPs). The results show very good reflecting properties of these mirrors for a propagating SPP whose wavelength is inside the gap. Another passive configuration employed was a plasmonic resonator consisting of dielectric-loaded surface plasmon polariton waveguide ring resonator (WRR). Also, a more robust variant has been proposed by replacing the ring in the WRR with a disk (WDR). The performance in terms of wavelength selectivity and efficiency of the WDRs was evaluated and was shown to be in good agreement with numerical results. Control of SPP signal was demonstrated in the WRR configuration both electro-optically and all-optically. In the case of electro-optical control, the dielectric host matrix was doped with an electro-optical material and combined with an appropriate set of planar electrodes. A 16% relative change of transmission upon application of a controlled electric field was measured. For all-optical control, nonlinearity based on trans-cis isomerization in a polymer material is utilized. More than a 3-fold change between high and low transmission states of the device at milliwatt control powers ( ~100 W/cm^2 intensity) was observed. Beyond the active control of propagating surface plasmons, further advancement can be achieved by means of nanoscale plasmonic structures supporting localized surface plasmons (LSP). Interactions of molecular excitations in a pi-conjugated polymer with plasmonic polarizations are investigated in hybrid plasmonic cavities. Insights into the fundamentals of enhanced light-matter interactions in hybrid subwavelength structures with extreme light concentration are drawn, using ultrafast pump-probe spectroscopy. This thesis also gives an overview of the challenges and opportunities that hybrid plasmonic functionalities provide in the field of plasmon nano optics.
Las nanoestructuras plasmónicas han adquirido una importante relevancia como herramientas capaces de manipular los fotones en la nanoescala, y pueden llegar a revolucionar un amplio abanico de aplicaciones tales como los circuitos ópticos integrados, la fotovoltaica o los dispositivos biosensores. Dichas estructuras hacen posible la miniaturización de los componentes ópticos más allá del “límite de difracción” de la luz, ya que convierten la radiación óptica en campos electromagnéticos fuertemente confinados en la proximidad de estructuras metálicas de tamaño inferior a la longitud de onda mediante la excitación de plasmones de superficie (SPs). Estos campos electromagnéticos tan intensos generados en los llamados “puntos calientes” plasmónicos brindan perspectivas muy interesantes para la generación de efectos no lineales en medios activos. El área de investigación denominado plasmónica activa busca la modulación de los SPs sostenidos por la intercara entre un metal y un material no lineal mediante una señal de control externa. El índice de refracción del material no lineal cambia bajo la aplicación de la señal de control, lo cual da lugar a la modificación de la respuesta plasmónica. Estas nanoestructuras híbridas también hacen posible la aparición de nuevos tipos de estados híbridos, lo cual proporciona tanto herramientas para diseñar dispositivos plasmónicos activos como mecanismos que permiten re-examinar las reglas convencionales de la interacción luz materia. Por lo tanto, es necesario el estudio de dichas nanoestructuras plasmónicas híbridas de manera teórica y experimental. En este trabajo de tesis se analiza el control de los SPs excitados en sistemas híbridos que combinan materiales activos y nanoestructuras metálicas mediante una señal óptica externa o un voltaje aplicado. Se han investigado distintos tipos de geometrías plasmónicas utilizando herramientas de simulación basadas en métodos en el dominio de la frecuencia, y posteriormente se han caracterizado experimentalmente dichas geometrías mediante técnicas de campo cercano y de campo lejano tales como la microscopía óptica de campo cercano y la microscopía basada en pérdidas radiativas, respectivamente. En primer lugar se estudiaron elementos plasmónicos pasivos, en particular espejos plasmónicos dieléctricos que demuestran la capacidad que tienen las redes periódicas de caballones de material dieléctrico colocados sobre una superficie metálica plana para abrir intervalos prohibidos en la relación de dispersión de los plasmones de superficie propagantes o plasmones-polaritones de superficie (SPPs). Los resultados muestran que dichos espejos poseen muy buenas propiedades reflectantes para SPPs cuya energía está en el intervalo prohibido. Otra configuración pasiva analizada fueron los resonadores plasmónicos basados en anillos de guía de onda plasmónica fabricada a partir de estructuras dieléctricas sobre metal (WRR, del inglés waveguide ring resonator ). Asimismo, se propone una versión más robusta de resonador plasmónico, basada en la sustitución del anillo del WRR por un disco (WDR, del inglés waveguide disk resonator). Se ha evaluado el funcionamiento de los WDRs en términos de selectividad en longitud de onda y de eficiencia, y los resultados obtenidos presentan un buen acuerdo con las predicciones numéricas. Pasando a las configuraciones activas, se demuestra el control de la señal plasmónica en configuración WRR por medios tanto electro-ópticos como completamente ópticos. En el caso del control electro-óptico, el material dieléctrico que compone el WRR estaba dopado con un componente electro-óptico y a la estructura pasiva se le añadió un conjunto de electrodos planos. Bajo la aplicación de un campo eléctrico externo, se midió un cambio relativo en la transmisión a través de la guía plasmónica del 16%. En cuanto al control puramente óptico, se utilizó la no linealidad de un material polimérico con origen en una isomerización trans-cis. En este caso se detectó un factor 3 entre los estados de alta y baja transmisión del dispositivo con potencias de control del orden de milivatios (intensidad del haz óptico de control de unos 100W/cm2 aproximadamente). Además del control activo de los plasmones de superficie propagantes, la utilización de nanoestructuras plasmónicas que poseen resonancias plasmónicas localizadas puede dar lugar a nuevos fenómenos. En esta tesis también se han estudiado las interacciones entre las excitaciones moleculares en un polímero pi-congujado con las polarizaciones plasmónicas en nanocavidades plasmónicas híbridas. Utilizando espectroscopia de tipo bombeo-sonda con pulsos ultrarrápidos, se han analizado diversos aspectos del aumento en la interacción luz-materia para estructuras híbridas de dimensiones inferiores a la longitud de onda sometidas a concentraciones de luz muy altas. Por último, esta tesis también proporciona una visión general de los desafíos y posibilidades que las funcionalidades plasmónicas híbridas ofrecen en el campo de la nano-óptica basada en plasmones de superfície.

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50

Frigerio, Federico Ph D. Massachusetts Institute of Technology. "3-dimensional surface imaging using Active Wavefront Sampling". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/38258.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.
Includes bibliographical references (p. 129-130).
A novel 3D surface imaging technique using Active Wavefront Sampling (AWS) is presented. In this technique, the optical wavefront traversing a lens is sampled at two or more off-axis locations and the resulting motion of each target feature is measured. This target feature image motion can be used to calculate the feature's distance to the camera. One advantage of this approach over traditional stereo techniques is that only one optical train and one sensor can be used to obtain depth information, thereby reducing the bulk and the potential cost of the equipment. AWS based systems are also flexible operationally in that the number of sampling positions can be increased or decreased to respectively raise the accuracy or to raise the processing speed of the system. Potential applications include general machine vision tasks, 3D endoscopy, and microscopy. The fundamental depth sensitivity of an AWS based system will be discussed, and practical implementations of the approach will be described. Algorithms developed to track target features in the images captured at different aperture sampling positions will be discussed, and a method for calibrating an AWS based method will also be described.
by Federico Frigerio.
Ph.D.

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