Tesi: "Micro-interaction"

1

Greville-Harris, G. "Child-infant interaction : A micro-analysis". Thesis, Open University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371040.

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2

Choudhary, Dhruv. "Micro-scheduling and its interaction with cache partitioning". Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41167.

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The thesis explores the sources of energy inefficiency in asymmetric multi- core architectures where energy efficiency is measured by the energy-delay squared product. The insights gathered from this study drive the development of optimized thread scheduling and coordinated cache management strategies in an important class of asymmetric shared memory architectures. The proposed techniques are founded on well known mathematical optimization techniques yet are lightweight enough to be implemented in practical systems.

3

Phelipot, Annabelle. "Interaction sol-structure lors d'opérations de micro-tunnelage". Lyon, INSA, 2000. http://theses.insa-lyon.fr/publication/2000ISAL0087/these.pdf.

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Ce travail s'inscrit dans le cadre du Projet National de Recherche français "Microtunnels". Le rnicrotunnelage est une technique de pose de canalisations sans tranchée. Elle consiste à foncer la canalisation à l'arrière d'un microtunnelier ayant les fonctions d'excavation, de marinage et de guidage. Cette méthode récente, permettant de réduire les nuisances liées à la pose des réseaux en tranchée, se développe principalement dans le cadre du génie civil urbain. Cette étude essentiellement expérimentale concerne principalement les problèmes liés au frottement à l'interface sol-canalisation, à la stabilité du front de taille, et enfin aux mouvements induits au sein du massif de sol traversé. Une première phase d'observations de terrain, basée sur le sui vi complet de chantiers de rnicrotunnelage dans des conditions de sol diverses, comportait la caractérisation des terrains traversés ainsi que l'enregistrement des principaux paramètres de fonçage et de pilotage. L'interprétation de ces données a permis de mettre en évidence l'incidence de la nature des terrains, de la surcoupe, de la lubrification et des problèmes de guidage sur les frottements mobilisent, sans permettre toutefois de toujours faire la part de chacun de ces paramètres. Les problèmes de stabilité du front et leur incidence sur les mouvements du sol ont pu également être observés et analysés. A partir de ces résultats, une étude complémentaire, dans des conditions bien contrôlées, a été entreprise dans une chambre de calibration adaptée à la modélisation du fonçage de canalisations. Les essais réalisés ont permis de cerner plus précisément l'incidence de la surcoupe et de l'injection de lubrifiant sur les frottements mobilisés et sur les mouvements engendrés dans le massif. L'incidence de la surcoupe a été modélisée à l'aide de simulations numériques bidimensionnelles en vue de l'extension aux conditions institue
This work comes within the scope of the « Microtunnels » French National Project. The micro-tunneling technique is a trenchless process for installing small diameter pipes. It consists in jacking pipe elements behind the boring machine performing excavation, spoil removal and steering operations. The main advantage of this recent method is a reduction in disturbances compared to traditional open-trench techniques. Therefore, it is especially useful and adapted in urban areas. This experimental study principally focuses on the main aspects of the technique:. / soil/pipe interface friction,. / face stability. / ground movements induced by microtunneling technique. In the first part, the complete monitoring at several microtunneling sites is reported. In particular, encountered soils are characterized (through in-situ and laboratory tests) and the main jacking and steering data are monitored. The in depth analysis of these data shows the great influence of ground nature, overcut, lubrication and pipe misalignments on mobilized friction. However, the respective contribution of each of the aforementioned parameters is not clearly identified. Face stability and ground \. 10vements are also observed and analyzed. Based on these in-situ results, a complementary experimentation has been designed and set up. Pipe jacking has been reproduced in a calibration chamber with a detailed and precise procedure and a full monitoring of ground displacements in the vicinity of the pipe and the pipe’s displacements and stresses. The influence of overcut, lubricant injection on the mobilized friction and the associated ground movements is precisely evaluated. In addition. The overcut effect has been simulated by numerical 2D calculations in order to use them to in-situ conditions

4

Rabaud, David. "Manipulation et interaction de micro-bulles sous champ acoustique". Phd thesis, Grenoble, 2010. http://tel.archives-ouvertes.fr/tel-00536932.

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Cette thèse traite de l'action des ondes acoustiques sur des bulles micrométriques excitées à leur fréquence de résonance. En effet, les bulles peuvent être considérées comme des oscillateurs mécaniques et les forces acoustiques à leur résonance, appelées forces de Bjerknes, ont des propriétés non triviales. De plus, les bulles interagissent entre elles par l'émission d'un champ secondaire, menant à leur auto-organisation sur un motif périodique. Ici, les bulles sont confinées dans des microcanaux, elles ne sont pas sphériques et frottent fortement sur les parois. L'étude expérimentale des forces acoustiques (primaire et secondaire) est alors précédée par la modélisation de l'écoulement des bulles, liant la friction sur les parois aux forces externes appliquées. Plusieurs applications aux laboratoires sur puce sont développées, dont le tri en taille, la division asymétrique contrôlée, l'aiguillage automatique à une bifurcation, et la manipulation de goutte.

5

Anselmucci, Floriana. "Interaction sol-racines : effets sur la micro-structure du sol". Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALI064.

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Cette thèse de doctorat présente une recherche expérimentale innovante sur la réponse mécanique du sable à la croissance des racines des plantes. L'interaction entre les racines et le sol est étudiée pour deux systèmes racinaires différents -- correspondant au maïs et au pois chiche -- et deux granulométries différentes du sable d’Hostun, dans deux états de porosité initiale.Un protocole est mis au point afin de créer des échantillons présentant une bonne répétabilité de leurs propriétés initiales, et représentatifs des interactions naturelles entre racines et sol. Deux campagnes expérimentales ont été conduites sur la base de séries d’échantillons comportant différentes plantes et différents états initiaux de sable. Une analyse 4D (3D + temps) de l'interaction est effectuée grâce à la tomographie à rayons X.Chaque échantillon est scanné en moyenne 7 fois, depuis le jour du semis jusqu'au 7e jour de développement du système racinaire. Un traitement d’image spécifique a été développé et appliqué aux images 3D reconstruites à partir des radiographies à rayons x. Ce traitement d’image permet entre autres d’identifier le système racinaire ainsi que les grains de sable, mais aussi de déterminer la teneur en eau locale du sol. Ainsi, un volume comportant quatre phases, représentatif du système sol-racines, est défini pour chaque état auquel un échantillon est imagé. Par ailleurs, en s’appuyant sur les images 3D en niveaux de gris, la cinématique du système est mesurée par application de corrélations d’images dites locales et discrètes.Les mesures de porosité locale (déduites des volumes à 4 phases) et les champs de déformation du sable (déduits des corrélations d’images) sont détaillés pour chaque configuration initiale du système sable-plante.Concernant l’impact de l’état initial du sable sur le développement des systèmes racinaires : la comparaison des différentes configurations montre, entre autres, que la densité du sable joue un rôle clef sur l’expansion du système racinaire, ceci pour les deux plantes considérées.Concernant la réponse du sable à la croissance des racines : le tenseur des déformations montre un cisaillement du sol lors de la croissance d’une racine. La zone cisaillée autour de la racine est plus large pour une plus faible densité initiale du sable. La détermination de la réponse volumique du sable à la croissance d’une racine, et sa dépendance à la densité du sol a aussi fait l’objet d’une attention particulière. Ainsi, dans la zone cisaillée, la sable présente une réponse purement dilatante pour les états initiaux les plus denses, alors que les états les plus lâches montrent un comportement contractant, particulièrement à distance de la racine. De telles réponses sont observées à la fois pour le maïs et le pois chiche. De plus, le comportement contractant, induit par le cisaillement à distance de la racine, est aussi confirmé pour les deux granulométries du sable pris dans l’état le plus lâche
This PhD thesis presents an innovative experimental investigation on the mechanical response of sand to plant root growth.Root-soil interaction is investigated for two different root systems -- Maize and Chickpea -- and two different gradings of Hostun sand with two initial porosities.An original protocol is developed aiming to create samples with repetitive initial nominal properties and representative of the natural interaction.Two experimental campaigns were run on a series of samples with different sands and plants.A 4D (3D+time) analysis of the interaction is carried out by using x-ray Computed Tomography.For each sample, an average of 7 x-rays scans is performed, from the day of the seed sowing up to 7-days-old root system.An image processing technique has been developed and it is applied to the 3D images resulting from the reconstruction of the x-ray scans. Through this image processing, the root system is identified, together with the sand grains and the water present in the system. Finally, a four-phased volume representative of the soil-root system can be defined for each state of the observed samples.Besides, from the 3D greyscale images of the samples, measurements of the kinematics of the system are obtained through local and discrete approaches of image correlation.Local sand porosity and deformations resulting from the four-phased volumes and the image correlations are detailed for one sample of each root-sand configuration.Regarding the impact of the initial sand state on the root system development, the comparison of the different configurations shows, among other things, that the sand density plays a key role on the expansion of the root system, for both plant species.Concerning the sand response to the root growth, the strain tensor computed with image correlation shows that a root shears the soil while growing and the sheared zone is wider when the initial bulk density is lower.This work focuses also on the determination of the sand volumetric response to root growth in the sheared zone and its dependency on the soil density.Sand response is purely dilatant for denser initial states, while the looser sand exhibits a contractant behaviour far from the root surface. Such a response is obtained in the case of both maize and chickpea. Moreover, the contractant behaviour induced by the shearing away from the root is confirmed also for both sand granulometries in a looser state

6

Naemat, Abida. "Biomolecular imaging of host-pathogen interaction by Raman micro-spectroscopy". Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/39476/.

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Abstract (sommario):

The ability of pathogens and their surrogate host cells to exchange molecules is at the core of all host-pathogen interaction processes. Small chemical molecule signals provide a rich vocabulary for cellular communication, and pathogens have evolved the capacity to modulate, mimic or hijack these signals in a defensive, exponentially increasing the scope and complexity of this chemical language between host cells and pathogens. The objective of this work is to use Raman microscopy (RMS) to analyze molecular changes during infection of human cells by intra- (Toxoplasma gondii) and extra-cellular (Acanthamoeba castellanii) protozoan parasites. The work is divided into two parts. Firstly, we studied host-pathogen biomolecular interaction by using RMS. Secondly, we employed stable isotopes substitution technique to induce spectral changes that are specific to the labelled molecules. In this approach mammalian cells are selectively grown in culture medium in which only certain molecules are substituted with stable-isotope counterparts, and the exchange of these molecules are monitored between individual mammalian cells and parasites in real-time. Our results show that Raman spectroscopy can be a great tool to understand the molecular processes that mediate the interaction between the pathogens and host cell by providing quantitative spatially- and temporally-resolved information regarding molecular trafficking and exchanges. A better understanding of these complex interactions will advance our understanding of microbial pathogenesis and potentially identify new therapeutic targets.

7

Molinelli, Chiara. "Interaction optomécanique à trois modes et refroidissement d'un micro-résonateur mécanique". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2011. http://tel.archives-ouvertes.fr/tel-00635999.

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Dans ce manuscrit nous présentons une expérience de mesure optique ultrasensible des vibrations mécaniques d'un micro-miroir dans une cavité Fabry-Perot de grande finesse. Le micro-miroir est constitué d'un résonateur de taille micrométrique en silicium, de fréquence de résonance de l'ordre du mégahertz, sur lequel est déposé un traitement optique de haute réflectivité. La sensibilité très élevée des mesures interférométriques est en principe suffisante pour observer les fluctuations quantiques de point zéro du résonateur. Pour atteindre le régime où l'énergie d'agitation thermique du micro-résonateur devient négligeable devant celle de l'état quantique fondamental, sa température doit être inférieure à 30 microKelvin. Afin d'approcher cette température, nous avons utilisé à la fois des méthodes cryogéniques traditionnelles et une technique de refroidissement laser basée sur les effets dynamiques de la pression de radiation dans une cavité désaccordée. Nous avons ainsi étudié la possibilité de combiner mesures optiques de haute sensibilité et cryogénie en plaçant le micro-résonateur et la cavité dans un cryostat à circulation d'hélium liquide. Nous avons mesuré le spectre de bruit thermique à température cryogénique et réalisé un refroidissement par pression de radiation du micro-résonateur. Nous avons également étudié un nouveau mécanisme de couplage optomécanique à trois modes, à bandes latérales résolues, plus efficace pour refroidir un micro-résonateur. Nous avons mis en évidence à la fois un effet de réduction et d'augmentation de la température effective du micro-miroir selon le couplage des modes optiques. Cette technique permet également d'étudier le phénomène des instabilités paramétriques pouvant apparaître dans les interféromètres gravitationnels de seconde génération.

8

Gallagher, Timothy. "Towards multi-scale reacting fluid-structure interaction: micro-scale structural modeling". Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53483.

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The fluid-structure interaction of reacting materials requires computational models capable of resolving the wide range of scales present in both the condensed phase energetic materials and the turbulent reacting gas phase. This effort is focused on the development of a micro-scale structural model designed to simulate heterogeneous energetic materials used for solid propellants and explosives. These two applications require a model that can track moving surfaces as the material burns, handle spontaneous formation of discontinuities such as cracks, model viscoelastic and viscoplastic materials, include finite-rate kinetics, and resolve both micro-scale features and macro-scale trends. Although a large set of computational models is applied to energetic materials, none meet all of these criteria. The Micro-Scale Dynamical Model serves as the basis for this work. The model is extended to add the capabilities required for energetic materials. Heterogeneous solid propellant burning simulations match experimental burn rate data and descriptions of material surface. Simulations of realistic heterogeneous plastic-bound explosives undergoing impact predict the formation of regions of localized heating called hotspots which may lead to detonation in the material. The location and intensity of these hotspots is found to vary with the material properties of the energetic crystal and binder and with the impact velocity. A statistical model of the hotspot peak temperatures for two frequently used energetic crystals indicates a linear relationship between the hotspot intensity and the impact velocity. This statistical model may be used to generate hotspot fields in macro-scale simulations incapable of resolving the micro-scale heating that occurs in heterogeneous explosives.

9

Foot, T. "The influence of peer interaction in micro-computer based problem-solving". Thesis, University of Southampton, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374863.

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10

Zhou, Lianqun. "Study of the membrane-fluid interaction in micro lamb wave sensor". Besançon, 2010. http://www.theses.fr/2010BESA2041.

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Micro lamb wave sensor is one of useful tools to study the membrane-fluid interaction, especially in interdisciplinary and not yet explored areas, such as gas sensing, aerodynamics, the multi-parameter decoupling and so on. This is because micro Lamb wave sensor holds high sensitivity, low losses and multi-modes. This thesis deals with the membrane-fluid interaction with micro lamb wave sensor is investigated, and the potential function method is used to analyze the dispersion curves, the displacements, the stress curves, etc. A model is built to analyze the modes distribution in micro Lamb wave sensor. The gase effects on lamb wave propagations are investigated. The applications of Lamb wave in aerodynamics and multi-parameters decoupling are discussed. The details are described as follows. In theory, combinations of the potential function method and the boundary conditions at all interfaces are used to analyze the membrane-fluid interaction. Compared with traditional plate shell theory, the particle movements in the membrane and fluid are taken into account in this method. Several aspects of the problem can be addressed, including the displacement, the stress, velocity dispersion curve, pointing vector, group velocity, energy velocity and so on. All of these are available to investigate the interaction at the membrane-fluid interface. In the case of micro Lamb wave sensor, the resonant modes can be excited and work simultaneously with the travelling modes, as the membrane is width limited and not large enough comparing with the wavelength of Lamb waves. The established model car reveal the mode distributions in micro Lamb wave device clearly and accurately. These works provide insight into the understandings of the modes in micro Lamb wave device, which is useful for further experiments. In literatures, little attention has been paid on the Lamb wavesۥ propagation near the membrane-gas interface, as both the density and sound velocity of gas are low. We aim to provide more studies of gases effects on the evanescent wave the leaky wave near the membrane-gas interface. It is shown that the relative frequency shifts in the low frequency range of the A0 mode (evanescent wave, EW) is rather important and the shape of the curve looks like ۥUۥ shape; in the high frequency range of this mode (leaky Lamb wave, LLW), the quality factor decreases rapidly when the Lamb wave phase velocity approaches the gas sound velocity. The Sº mode shows immune to gas loading, which is a good choice for a reference mode. This provides theoretical and experimental work for related fields in gas sensing. The application of membrane-gas interaction in aerodynamics in investigated theoretically and experimentally. The interaction between the gas flow boundary layer and the acoustic sound field (EW and LLW) at the membrane-gas interface can give out the parameter in the gas flow. The parameters in gas flow can be obtained from the measuring the interaction, which happens between the gas flow boundary layer and the acoustic sound field (EW and LLW) at the membrane gas interface. In the EW case, the thicknesss of the gas flow boundary layer and the penetration depth of the evanescent wave combined determine this interaction. When the Lamb wave phase velocity approaches the gas sound velocity, this effect is clearly observed. In the LLW case, it is shown experimentally that the gas flow has not evident effects on Lamb wave’s propagations. It suggests that Lamb wave is promising for applications in wind tunnel experiments, micro channels characterization, and can lead to multi-parameters measurements. The effects of the different physical parameters (density, sound velocity, viscosity, etc) on the modesۥ propagations at he membrane-liquid interface are studied. Combination of the relative frequency shifts of the A01 mode (he fundamental mode of low frequency A0 mode) and the A03 mode (the third harmonic wave of the A01 mode), the density and the sound velocity of liquid, but is amplitude changes with the viscosity. This work makes Lamb wave have promising applications in the investigation of the molecular thermodynamics, molecular labels free detection,etc
Cette thèse traite, théoriquement et expérimentalement, de l’interaction fluide-membrane dans un capteur a onde de Lamb. Un modèle est utilisé pour calculer les courbes de dispersion, le déplacement, les contraintes. Un autre modèle est utilisé pour analyser la distribution des modes. L’effet des gaz est étudié théoriquement et expérimentalement. Les applications des ondes de Lamb à l’aérodynamique et aux mesures multiparamétriques sont présentées. Voici quelques détails. Le premier modèle utilise les fonctions potentielles et recherche les fonctions solution des équations de propagation qui remplissent les conditions aux limites avec ou sans la présence d’un liquide. Ce modèle permet d’obtenir de nombreux paramètres, le déplacement des particules, les contraintes, le vecteur de Poynting, les vitesses de groupe et d’énergie etc. La membrane étant limitée dans le sens latéral il y a coexistence dans la membrane de modes stationnaires et d’ondes progressives. Un modèle donne la position et l’intensité relatives des modes. Le but est d’apporter des connaissances complémentaires sur l’action des gaz sur la propagation des ondes de Lamb. On montre que pour les basses fréquences de A0 (ondes évanescentes dans le gaz) l’action est principalement un changement de fréquence , tandis aux plus hautes fréquences de A0 (Ondes «fuyantes» l’action est principalement une atténuation. Le S0 mode étant très peu modifié par la présence de gaz. L’application de l’interaction gaz-membrane en aérodynamique est étudiée théoriquement et expérimentalement. Le principal effet ce produit quand la vitesse de phase de l’onde de Lamb est proche de la vitesse du son dans le gaz. Les résultats suggèrent que les applications dans ce domaine seront très prometteuses. Les effets sur l’onde de Lamb de différents paramètres (densité, vitesse du son viscosité) d’une solution liquide sont étudiés. On montre que l’utilisation conjointe de A01 mode (fondamental du A0 mode) et du A03 mode (harmonique 3 DU A0 mode) permet de mesurer la densité et la vitesse du son. La densité étant connue, le S0 mode permet d’obtenir la viscosité

11

Byrd, Alex W. "Fluid-Structure Interaction Simulations of a Flapping Wing Micro Air Vehicle". Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1401559891.

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12

Kovalick, Walter W. "Improving federal interagency coordination: a model based on micro-level interaction". Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/53559.

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Public institutions are becoming ever more dependent upon one another due to their complexity and specialized programs. There is a growing potential for duplication and/or overlap. It is in the context of an increasing need for coordinated action—especially among Federal agencies—that this dissertation is written. This dissertation posits a model for Federal interagency cooperation that moves beyond traditional interorganizational coordination literature and its exchange-based concept of cooperation. Drawing from the principles of authentic management founded in humanistic psychology and the negotiation literature, it suggests that such interorganizational cooperation is developed and nurtured at the micro level. Only through contactful engagement of the principals can the interests of the parties be revealed and dealt with to completion. In addition, this dissertation recognizes the unique character of such engagement when it takes place in pursuit of the public interest, as opposed to more traditional private settings. This dissertation examines this model in the context of a unique interagency organization—the Interagency Regulatory Liaison Group (IRLG). This IRLG was formed by the chief executives of the five Federal health and safety regulatory agencies in 1977. It operated for four years with their personal involvement and enthusiasm until its charter expired in 1981. Involving hundreds of employees from the five agencies, it stands as a unique organizational experiment in cooperative activities. This dissertation applies the IRLG experience, as seen through in-depth interviews with the agency heads and staff, to the micro-level model. The IRLG experience illustrated the model concepts of contactful engagement and integrative bargaining at the Federal interagency level. It showed the importance of the agential perspective on the part of the chief executives as they worked together on joint projects. It also illustrated the essentiality of building a lingua franca—a common language—for discussion and resolution of interorganizational differences. Finally, the emphasis in the model on maintaining both the substantive and process aspects on on-going interagency coordination is shown in the IRLG.
Ph. D.

13

Ozcelik, Hayriye. "Interaction Between Micro And Nano Patterned Polymeric Surfaces And Different Cell Types". Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614798/index.pdf.

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ABSTRACT INTERACTION BETWEEN MICRO AND NANO PATTERNED POLYMERIC SURFACES AND DIFFERENT CELL TYPES Ö
zç
elik, Hayriye Ph.D., Department of Biology Supervisor: Prof. Dr. Vasif Hasirci Co-Supervisor: Dr. Celestino Padeste August 2012, 139 pages Micro and nanopatterned surfaces are powerful experimental platforms for investigating the mechanisms of cell adhesion, cell orientation, differentiation and they enable significant contributions to the fields of basic cell and stem cell biology, and tissue engineering. In this study, interaction between micro and nanopatterned polymeric surfaces and different cell types was investigated. Three types of micropillars were produced by photolithography (Type 1-3), while nanometer sized pillars were produced in the form of an array by electron beam lithography (EBL). Replica of silicon masters were made of polydimethylsiloxane (PDMS). Polymeric [P(L-D,L)LA and a P(L-D,L)LA:PLGA blend] replica were prepared by solvent casting of these on the PDMS template and used in in vitro studies. The final substrates were characterized by various microscopic methods such as light microscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM). In order to investigate deformation of the nucleus in response to the physical restrictions imposed by micropillars, Type 1 and Type 2 pillars were used. These substrates were covered with pillars with different interpillar distances. While Type 1 is covered with symmetrically (in X-Y directions) distributed pillars, Type 2 pillars were distributed asymmetrically and the inter-pillar distances were increased. Nuclei deformation of five cell v types, two cancer cell lines (MCF7 and Saos-2), one healthy bone cell (hFOB1.19), one stem cell (bone marrow origined mesemchymal stem cells, BMSCs) and one standard biomaterial test cell type, (L929) fibroblasts was examined by using fluorescence microscopy and SEM. The nuclei of Saos-2 and MCF7 cells were found to be deformed most drastically. Nucleus deformation and intactness of nuclear membrane was examined by Anti- Lamin A staining. The interaction of the cells with micropillars was visualized by labelling focal adhesion complexes (FAC). Wettabilities of patterned and smooth surfaces were determined. As the patterns become denser (closer micropillars, Type 1) the hydrophobicity increased. Similar to water droplets, the cells were mostly spread at the top of the Type 1 pillars. The number of cells spread on the substrate surface was much higher on Type 2 patterned films. In order to support these qualitative findings, nucleus deformation was quantified by image analysis. Frequency of nucleus deformation was determined as the ratio of deformed to the total number of nuclei (%). In order to quantify the intensity of nuclei deformation, their circularity was evaluated. In addition to nucleus deformation, alterations in the ratio of cell area-to-nucleus area in response to micropillars were determined by image analysis. The results indicated that cancerous cells were more deformable. The qualitative microscopic evaluation and the data obtained by quantification of the nucleus and cellular deformation were in good agreement. In addition, the findings were consistent with expectations which suggest that cancerous cells are &ldquo
softer&rdquo
. In the second part of the research the force applied by the cells on arrays of micropillars with high aspect ratios (Type 3 substrates) during tugging at the pillars was investigated. Micropillars were produced using P(L-D,L)LA as well as a 60:40 blend of P(L-D,L)LA with PLGA. The blend is a material with lower stiffness than P(L-D,L)LA. The mechanical properties of the two materials were determined by tensile testing of solvent cast films. Deformation of Type 3 micropillars by the cellular tugging force of Saos-2 and L929 was studied by fluorescence and SEM microscopy, both on stiff and softer substrates. Displacements of the centers nodes of the pillars were evaluated from SEM micrographs. On the stiff surface, the two cell types bent the pillars to the same extent. On the other softer substrate (blends), however, the maximum displacements observed with Saos-2 cells were higher than the ones caused on the stiffer substrate or the ones caused by L929 cells. It is reported that stiffness of the substrate can determine stem cell lineage commitment. In order to examine the effects of change of substrate stiffness on osteogenic differentiation of BMSCs, osteopontin (OPN) expression was determined microscopically. It was found that osteogenic differentiation is enhanced when BMSCs are cultured on P(L-D,L)LA Type 3 pillars. vi In the last part of research, arrays of nanopillars whose interpillar distances systematically varied to form different fields were examined in terms of adhesion and alignment in order to determine the differential adhesion of BMSCs and Saos-2 cells. The difference in their adhesion preference on nanopillar arrays was quantified by image analysis. It was observed that BMSCs and Saos-2 cells behaved in an opposite manner with respect to each other on the fields with the highest density of nanopillars. The BMSCs avoided the most densely nanopillar covered fields and occupied the pattern free regions. The Saos-2, on the other hand, occupied the most densely nanopillar covered fields and left the pattern free regions almost unpopulated. It was also found that both BMSCs and Saos-2 cells aligned in the direction of the shorter distance between the pillars. Both BMSCs and Saos-2 cells started to align on the pillars if the distance in any direction was >
1.5 &mu
m. To better understand the effects of chemical and physical cues, protein coating and material stiffness were tested as two additional parameters. After fibronectin coating, the surfaces of P(L-D,L)LA films with the highly dense pillar covered fields, which were avoided when uncoated, were highly populated by the BMSC. Similarly, decreasing the stiffness of a surface which was normally avoided by the BMSCs made it more acceptable for the cells to attach.

14

Hupp, Sara J. (Sara Jean) 1979. "A tribological study of the interaction between surface micro texturing and viscoelastic lubricants". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30298.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.
Includes bibliographical references (p. 116-117).
An experimental study is performed on micro textured surfaces using both elastic and Newtonian fluids in order to understand the effect of surface texturing and fluid rheology on sliding friction under lubricated conditions. Nickel micro textured surfaces containing 50 to 125 micron diameter pores and 1 to 20 percent area densities of pores are fabricated using novel techniques inspired by MEMS fabrication methods in order to obtain a metal surface that is corrosion and wear resistant. These surfaces are then friction tested using a torsional rheometer with a parallel plate configuration, and the resulting data is normalized to obtain a Stribeck diagram that spans the lubrication regimes from boundary lubrication to hydrodynamic lubrication. Each lubricant/surface pair results in a unique curve that is subsequently compared to other lubricant/surface pairs in order to study the effect of different surface texturing parameters as well as the effect of the particular lubricant rheology. Experimental results from studying the effect of different surface texturing parameters indicate that particular micro textured patterns can reduce friction by as much as seventy-five percent after a controlled break-in period. Data from the tribo-rheometer also indicates that along with a reduction in friction, micro texturing can result in shifting the entire Stribeck curve so that the transition points between lubrication regimes are delayed or induced by as much as an order of magnitude of the Gumbel number, depending on the lubricant and running conditions. Focusing next on the effect of lubricant rheology on sliding friction over micro textured surfaces, this research reveals that the Stribeck curve will experience a shift according to the lubricant elasticity. A new dimensionless number formed by dividing the Gumbel number by the elasticity factor of the fluid can accurately account for the Stribeck curve shift as a result of fluid elasticity.
by Sara J. Hupp.
S.M.

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Colas, Laurent. "Etude experimentale de la turbulence sur tore supra par interaction plasma micro-ondes". Paris 11, 1996. http://www.theses.fr/1996PA112358.

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La turbulence magnetique a petite echelle est un candidat serieux pour expliquer le transport anormal de la chaleur dans les tokamaks. Dans ce travail on met en uvre un nouveau diagnostic pour mesurer des fluctuations magnetiques sur tore supra: la diffusion depolarisante. Cet outil experimental original est fonde sur la conversion de mode d'un faisceau de sondage micro-ondes polarise, par diffusion sur les fluctuations magnetiques au voisinage d'une couche de coupure. Le diagnostic est d'abord qualifie pour verifier qu'il est sensible aux fluctuations magnetiques, et que ses mesures sont localisees spatialement pres de la coupure. Le comportement du niveau de fluctuations est ensuite analyse sur un large domaine de courants plasma, densites et puissances additionnelles, et interprete a l'aide d'un modele 1d de diffusion depolarisante. Un balayage en densite ou en champ magnetique est utilise pour deplacer la zone d'origine des mesures. Un profil radial des fluctuations magnetiques est ainsi estime de deux manieres differentes. Dans les decharges avec chauffage additionnel, on etudie la relation entre les fluctuations magnetiques, la forme des profils de temperature et le transport local de la chaleur. A l'aide de toutes les mesures on peut chercher un parametre local correle avec la turbulence sur un large domaine de conditions plasma. Un coefficient local de transport de la chaleur induit par les fluctuations mesurees est estime par la formule quasi-lineaire non-collisionnelle. Les diffusivites calculees ont des valeurs absolues et variations parametriques proches de celles de diffusivites de la chaleur electronique determinees par une analyse du transport. Le dispositif de mesure est egalement sensible a la diffusion thomson du faisceau de sondage par les fluctuations de densite. Les mesures sont interpretees comme les fluctuations de l'amplitude et de la phase d'un interferometre, a l'aide d'un modele simple du mouvement poloidal des elements de plasma

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Bourgeois, Jacky. "Interactive demand-shifting in the context of domestic micro-generation". Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S141/document.

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La combinaison de l'internet des objets et des nouvelles technologies liées à l'énergie transforme le paysage de l'énergie dans la maison. Les installations de micro générateurs, dominées par les panneaux solaires photovoltaïques, sont en constante progression. C'est une opportunité pour la création et l'altération des comportements énergétiques. Cependant, ces transformations créent également un nouveau challenge que l'on appelle le « différentiel énergétique » à l'échelle de la maison : la consommation et la génération d'électricité des ménages sont désynchronisées. En effet, la génération locale est majoritairement incontrôlable et dépendante des conditions météorologiques alors que la consommation des ménages à tendance à se concentrer en soirée. Cette thèse vise à comprendre et supporter les pratiques de déplacement des consommations émergentes dans les ménages équipés de panneaux solaires photovoltaïques. En particulier, nous observons « Comment les outils numériques peuvent-ils tirer parti des pratiques de déplacement des consommations dans le contexte de micro génération domestique ? ». Pour adresser cette question nous avons combiné des approches empiriques et d'ingénierie, se renforçant et s'informant mutuellement les unes et les autres pour fournir une solution générale. Cela inclut la collection de données qualitatives et quantitatives, des analyses en collaboration avec les participants, des études longitudinales, des interviews, du co-design, des simulations et des tests en condition réelles. Tout au long de cette thèse, nous avons utilisé une méthodologie centrée sur l'utilisateur à chaque étape pour informer et valider la recherche en collaboration avec 38 ménages. A travers une investigation approfondi des routines telles que faire la lessive et se déplacer en voiture électrique, nous soulignons l'engagement naturel des ménages pour le déplacement des consommations. Cependant, cette activité se révèle complexe et fastidieuse. Nous révélons cette complexité à l'aide d'une analyse de donnée participative, une méthode élaborée afin d'analyser les données en collaboration avec les participants. Nous construisons une compréhension détaillée de la relation entre la génération d'électricité domestique et les routines du quotidien. Enfin, nous soulignons le besoin d'un support contextuel à travers le déploiement d'interventions sur le terrain. En perspective de la littérature, nous proposons un modèle conceptuel pour le support interactif de déplacement des consommations
The combination of ubiquitous computing and emerging energy technologies is radically changing the home energy landscape. Domestic micro-generation, dominated by solar photovoltaic, is increasing at a rapid pace. This represents an opportunity for creating and altering energy behaviours. However, these transformations generate new challenges that we call the domestic energy gap: domestic electricity consumption and micro-generation are out of sync. Micro-generation is mainly uncontrollable production relying on weather while domestic energy consumption tends to happen mostly during the evening. This thesis focuses on understanding and supporting new domestic practices in the context of domestic solar electricity generation, looking at ‘Demand-Shifting’. Specifically, we look at how can digital tools leverage Demand-Shifting practices in the context of domestic micro-generation? Relying on a mixed-method approach, we provide a qualitative and quantitative answer with the collaboration of 38 participating households in several field studies including two spanning more than eight months. Through a deep investigation of laundry and electric mobility routines in the context of domestic micro-generation, we emphasised a natural engagement into Demand-Shifting which appeared as a complex and time-consuming task for participants which was not visible when we analysed their quantitative data. We revealed this complexity through Participatory Data Analyses, a method we designed to analyse the data in collaboration with the participating householders. This provided us with a comprehensive view of the relationship between domestic micro-generation and daily routines. Finally, we highlight the need for timely and contextual support through the deployment of interventions in-the-wild. Building on discussions of our findings in perspective of the literature, we propose a conceptual framework to support domestic interactive Demand-Shifting (iDS)

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Arrabito, Giuseppe Domenico. "Micro and Nano patterns for Biosensing: from enzymatic assays to single cells interaction arrays". Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10761/975.

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In this thesis work, solution dispensing techniques have been employed for the realization of complex biological arrays. Inkjet printing techniques were employed for the generation of drug screening platforms. This approach was initially proved with a model enzyme system like Glucose Oxidase substrate covalently linked to a functionalized silicon oxide support. On this support an enzymatic substrate (D-glucose)/inhibitor (D-glucal) couple was accurately dispensed. A simple optical detection method was used to prove the screening capability of the microarray with the possibility to assay with high reproducibility at the single spot level. Afterwards, this methodology has been extended to CYP450 enzymes like CYP3A4, one of the main targets for the phase I drug metabolism via a droplet microreactors arrays containing CYP3A4 enzyme mixed with model inhibitors (erythromycin) and enzymatic chemiluminescent substrates (Luciferin-Isopropylacetate). The enzymatic activity was detected by using easy and low cost optical measurements of spot brightness. As a second main objective, high-throughput and multiplexed Dip Pen Nanopatterning methodologies in liquid format were combined with Proteic Ligand DNA-Directed Immobilization for the creation of complex protein biochips on modified glass surfaces displaying spots of cell-specific ligands with lateral dimensions minor than one single cell. In a first application the epidermal growth factor (EFG) protein arrays were realized to display specific single cell adhesion activity. As a second application, immobilized proteic ligands were used to recruit designed cellular receptors which presented intracellular protein domain whose interaction with a cytosolic binding partner was monitored and perturbated.

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Arrabito, Giuseppe Domenico. "Micro and Nano patterns for Biosensing: from enzymatic assays to single cells interaction arrays". Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10447/130487.

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In this thesis work, solution dispensing techniques have been employed for the realization of complex biological arrays. Inkjet printing techniques were employed for the generation of drug screening platforms. This approach was initially proved with a model enzyme system like Glucose Oxidase substrate covalently linked to a functionalized silicon oxide support. On this support an enzymatic substrate (D-glucose)/inhibitor (D-glucal) couple was accurately dispensed. A simple optical detection method was used to prove the screening capability of the microarray with the possibility to assay with high reproducibility at the single spot level. Afterwards, this methodology has been extended to CYP450 enzymes like CYP3A4, one of the main targets for the phase I drug metabolism via a droplet microreactors arrays containing CYP3A4 enzyme mixed with model inhibitors (erythromycin) and enzymatic chemiluminescent substrates (Luciferin-Isopropylacetate). The enzymatic activity was detected by using easy and low cost optical measurements of spot brightness. As a second main objective, high-throughput and multiplexed Dip Pen Nanopatterning methodologies in liquid format were combined with Proteic Ligand DNA-Directed Immobilization for the creation of complex protein biochips on modified glass surfaces displaying spots of cell-specific ligands with lateral dimensions minor than one single cell. In a first application the epidermal growth factor (EFG) protein arrays were realized to display specific single cell adhesion activity. As a second application, immobilized proteic ligands were used to recruit designed cellular receptors which presented intracellular protein domain whose interaction with a cytosolic binding partner was monitored and perturbated.

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Mallavajjala, Rahul. "Micro-Interactions on Smartphones : An email notification redesign". Thesis, Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-16659.

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Context. The mental effort offered by a user to identify an important email from the email message is considered significant or impossible. A user must enter the e-mail application to determine what type of e-mail they have received. To let the user identify the type of email via smartphone notification, micro-interactions are utilized. De augmentatie in UX of de e-mail notificaties is dan getest met de modificaties gemaakt aan de micro-interacties. Objectives. This study explores the microinteractions in an email notification of a smartphone that requires the modification of micro-interactions. These modifications have been implemented based on the design principles and usability heuristics of the existing literature. With this implementation, the augmentation in user experience of the modified design is determined. Methods. On conducting a systematic literature review, the experimental design of micro-interactions is prototyped. These prototypes are subjected to user interaction by conducting interviews that include performing certain tasks on the prototype and obtaining the user's perspectives regarding usability with an SUS scale. The data collected has been analyzed to obtain data on user experience increase. Since this data is tested for statistical significance to prove the theory and the evidence reinforce each other. Results. User interviews resulted in 100% of the users being able to perform the tasks successfully during the interaction with the prototypes. The modified design or email notifications achieve job performance time that is much less than the time used by the user for the existing design. Meanwhile, The SUS score for the modified design of micro-interactions with the existing design achieved the best imaginable score which reflects the rise in user experience of the e-mail notifications on a smartphone. On analysis, these achieved scores showed their statistical significance of the claim of increase in UX.Conclusions. This study concludes the reduction in cognitive load in a smartphone's email notifications by effective application or design principles in microinteractions. Regardless of the increased number of email arrivals on a device, a smartphone user can now identify the important e-mails on a smartphone directly from the email notifications. Following the Google's Material Design Principles resulted in increased user experience of e-mail notifications on a smartphone. However,

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Macente, Alice. "4-dimensional studies of fluid-rock interaction". Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/23473.

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Successful management of hydrocarbon reservoirs, geothermal energy extraction sites, radioactive waste and CO2 storage sites depends on a detailed knowledge of fluid transport properties, porosity and permeability. Amongst deformation processes, fluid-rock interaction plays an important role in controlling the petrophysical properties of a rock. The presence of fluids in the rocks induce chemical and physical changes in compositions and texture, affecting porosity and permeability, hence influencing dynamic transport properties and fluid flow. Fluid-rock interaction processes have been deeply investigated in nature and in numerous experimental and numerical modelling studies. However, these studies lack a spatio-temporal characterization of the dynamic evolution of porosity and reaction microfabrics. There is no clear understanding of the spatio-temporal evolution of these properties in three dimensions, and how this evolution affects fluid percolation in the rock. Computed X-ray micro-Tomography (μCT) was applied to investigate these processes in three dimensions and observe their evolution in time (4DμCT). The combination of μCT with 2D analytical techniques (e.g. scanning electron microscope, SEM, electron microcrobe, EMPA, electron backscatter diffraction, EBSD) furthermore enables the extrapolation of the information gained from 2D analyses to the 3rd an 4th dimension (4D μCT). The thesis investigates two different categories of fluid-rock interaction processes, by using 4DμCT to monitor the evolution of mineral reactions (in the first case) and porosity (second case) in relation to strain and time. In the first case study, natural rock samples were analysed. The samples show a compositional change along a strain gradient from olivinic metagabbros to omphacite-garnet bearing eclogites in a ductile shear zone. Synchroton-based x-ray microtomography (sμCT) was applied to document the 3D evolution of garnets along the strain gradient (which represent the 4th dimension). The 3D spatial arrangement of garnet microfabrics can help determine the deformation history and the extent of fluid-rock interaction active during deformation. Results from the sμCT show that in the low strain domain, garnets form a large and well interconnected cluster that develops throughout the entire sample and garnet coronas never completely encapsulate olivine grains. In the most highly deformed eclogites, the oblate shapes of garnets reflect a deformational origin of the microfabrics. EBSD analyses reveal that garnets do not show evidence for crystal plasticity, but rather they highlight evidence for minor fracturing, neo-nucleation and overgrowth, which points to a mechanical disintegration of the garnet coronas during strain localisation. In the second case study, pressure-solution processes were investigated using NaCl as rock-analogue, to monitor the evolution of porosity and pore connectivity in four dimensions, providing a time-resolved characterization of the processes. NaCl samples were uniaxially compacted and μCT scans were taken at regular interval times to characterize the evolution of grain morphologies, pore space and macro-connectivity of the samples. Different uniaxial loads, as well as different bulk sample compositions (phyllosilicates and/or glass beads) were used to investigate their effect on the process. Greater uniaxial loads, and the presence of phyllosilicates within the deforming NaCl columns were found to enhance pressure-solution processes. The pore space becomes highly disconnected in the presence of phyllosilicates, with important implications for fluid percolation and dynamic transport properties. Mean strain rates, calculated from volumetric Digital Image Correlation (3D-DIC) analyses, were found to be higher where phyllosilicates were located. The combination of μCT with volumetric DIC and SEM imaging proved to be an efficient analytical method for investigating the dynamic behaviour of porosity and permeability during ongoing pressure-solution processes. The results showed that fluid-rock interaction critically modifies the rocks at the pore/grain scale, with important consequences on dynamic fluid transport properties. The combination of μCT with classical 2D techniques provided a better understanding on the dynamic evolution of transport properties and fluid percolation during fluid-rock interaction processes, allowing the characterization in three dimensions of reaction microfabrics and porosity.

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Wagner, Frank. "Interaction laser matière à forts flux : Micro-usinage et endommagement laser dans le domaine nanoseconde". Habilitation à diriger des recherches, Aix-Marseille Université, 2012. http://tel.archives-ouvertes.fr/tel-00769459.

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Ce document décrit mon cheminement professionnel, en détaillant principalement mes activités de recherche successives qui, par delà les changements de pays et de thématiques précises, ont gardé le dénominateur commun " d'interaction lumière-matière ". Ce document débute par un curriculum vitae (section 1) qui résume les différentes étapes de mon cheminement professionnel (" Diplomarbeit " au Laser-Laboratorium Göttingen, Doctorat à l'Ecole Polytechnique Fédérale de Lausanne, Recherche dans une PME à Lausanne, Maître de Conférence à l'Université d'Aix-Marseille / Institut Fresnel) en précisant les responsabilités que j'ai assumées. Suit la liste de mes travaux (section 2), puis la liste des personnes dont j'ai encadré le travail (section 3). La section suivante résume mes activités d'enseignement (section 4). Le mémoire se termine ensuite avec le résumé de mes activités de recherche dans les deux dernières positions que j'ai occupées (section 5) et se conclut par une esquisse de mon projet scientifique (section 6) tel que je le perçois aujourd'hui. En annexe, j'ai finalement attaché les copies de quelques publications significatives sur différents aspects de mon travail.

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Yu, Xiaoming. "Laser micro/nano machining based on spatial, temporal and spectral control of light-matter interaction". Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32928.

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Doctor of Philosophy
Department of Industrial & Manufacturing Systems Engineering
Shuting Lei
Lasers have been widely used as a manufacturing tool for material processing, such as drilling, cutting, welding and surface texturing. Compared to traditional manufacturing methods, laser-based material processing is high precision, can treat a wide range of materials, and has no tool wear. However, demanding manufacturing processes emerging from the needs of nano and 3D fabrication require the development of laser processing strategies that can address critical issues such as machining resolution, processing speed and product quality. This dissertation concerns the development of novel laser processing strategies based on spatial, temporal and spectral control of light-matter interaction. In the spatial domain, beam shaping is employed in ultrafast laser micro-processing. Zero-order Bessel beam, generated by an axicon, is used for selective removal of the back contact layer of thin film solar cells. Bessel beam’s propagation-invariance property gives rise to an extension of focal range by orders of magnitude compared to Gaussian beam, greatly increasing process tolerance to surface unevenness and positioning error. Together with the axicon, a spatial light modulator is subsequently used to modify the phase of laser beam and generate superpositions of high-order Bessel beam with high energy efficiency. With the superposed beam, processing speed can be increased significantly, and collateral damage resulting from the ring structures in the zero-order Bessel beam can be greatly suppressed. In the temporal domain, it is demonstrated that ionization in dielectric materials can be controlled with a pair of ultraviolet and infrared pulses. With the assistance of the long-wavelength infrared pulse, nano-scale features are achieved using only a small fraction of threshold energy for the short-wavelength pulse. Computer simulation based on the rate equation model is conducted and found to be in good agreement with experimental results. This study paves the way for future adoption of short-wavelength laser sources, for example in the extreme ultraviolet range, for direct laser nano-fabrication with below-threshold pulse energy. In the spectral domain, a short-wavelength infrared laser is used to generate modification in the bulk of silicon wafers, in an attempt to develop 3D fabrication capabilities in semiconductors. Issues such as spherical aberration correction and examination procedure are addressed. Permanent modification is generated inside silicon by tightly focusing and continuously scanning the laser beam inside the samples, without introducing surface damage. The effect of laser pulse energy and polarization is also investigated. These results demonstrate the potential of controlling laser processing in multiple dimensions for manufacturing purposes, and point to a future when laser can be used as naturally and efficiently as mechanical tools used today, but is targeted at more challenging problems.

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Ai, Shiwen. "SENSING AND CONTROL OF TIP-SAMPLE INTERACTION FORCE OF A THREE-AXIS COMPLIANT MICRO-MANIPULATOR". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322626198.

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Das, Pritam. "Membrane micro-structurée utilisable comme support au développement de cellule humaine : développement, caractérisation et interaction cellule-matrice". Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30282/document.

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Les matériaux à structure tridimensionnelle laissent entrevoir de nombreuses applications prometteuses dans le domaine de l'ingénierie tissulaire et de la médecine régénérative en fournissant un micro-environnement approprié pour l'incorporation de cellules ou de facteurs de croissance afin de régénérer des tissus ou organes endommagés. Dans ce contexte, une membrane a été élaborée à partir d'un mélange de poly (ε-caprolactone) PCL / chitosan CHT à partir d'une technique d'inversion de phase permettant un apport localisé de non solvent. La technique permet d'obtenir une double morphologie poreuse : (i) des macrovides en surface (gros pores) facilement accessibles pour l'invasion et la viabilité des cellules; (ii) un réseau macroporeux interconnecté (petits pores) pour transférer les nutriments, l'oxygène, le facteur de croissance à travers le matériau. Les propriétés physico-chimiques (taille des pores, chimie de surface et biodégradabilité) des matériaux ont été caractérisées. Il est montré comment il est possible d'ajuster les propriétés de la membrane en modifiant le rapport PCL / CHT. Des cultures de cellules souches mésenchymateuses humaines (CSMh) ont été réalisées sur la membrane. La viabilité et la prolifération cellulaires ont été étudiées par des essais de test au MTT et de taux d'absorption d'oxygène. Les expériences démontrent que la membrane est biocompatible et peut être colonisée par les cellules. La microscopie confocale montre que les cellules sont capables de pénétrer à l'intérieur des macrovides de la membrane. La prolifération cellulaire de CSM dans ce matériau pourrait être utile pour augmenter la longévité d'autres cellules primaires en modifiant les CSM pour produire des facteurs de croissance. Pour tester le comportement dynamique des cellules sur la membrane, un dispositif d'organe sur puce a été développé avec des cellules endothéliales ombilicales humaines ensemencées sur la membrane. Les résistances hydrauliques de la barrière cellulaire sur la membrane ont été quantifiées en temps réel pour une pression trans-endothéliale (PTE), 20 cm H2O à 37 ° C et avec des cellules vivantes après 1 jour et 3 jours après l'ensemencement. Les résultats suggèrent que ce type d'échafaudages polymères peut être utile à l'avenir comme patch in vivo pour réparer des vaisseaux endommagés
Over the last decades, three-dimensional (3D) scaffolds are unfolding many promising applications in tissue engineering and regenerative medicine field by providing suitable microenvironment for the incorporation of cells or growth factors to regenerate damaged tissues or organs. The three-dimensional polymeric porous scaffolds with higher porosities having homogeneous interconnected pore network are highly useful for tissue engineering. In this context, a poly (ε- caprolactone) PCL/chitosan CHT blend membrane with a double porous morphology was developed by modified liquid induced phase inversion technique. The membrane shows: (i) surface macrovoids (big pores) which could be easily accessible for cells invasion and viability; (ii) interconnected microporous (small pores) network to transfer essential nutrients, oxygen, growth factors between the macrovoids and throughout the scaffolds. The physico-chemical properties (pore size, surface chemistry and biodegradability) of the materials have been characterized. This study shows how it is possible to tune the membrane properties by changing the PCL/CHT ratio. Human mesenchymal stem cell (hMSCs) culture was performed on the membranes and the cell viability and proliferation was investigated by MTT assay and oxygen uptake rate experiments. The experiments demonstrate that the membranes are biocompatible and can be colonized by the cells at micron scale. Confocal microscopy images show that the cells are able to adhere and penetrate inside the macrovoids of the membranes. Both cell proliferation and oxygen uptake increase with time especially on membranes with lower chitosan concentration. The presence of chitosan in the blend produces an increase of porosity that affect the entrapment of the cells inside the porous bulk of the membranes. Successful cellular proliferation of hMSCs could be useful to enhance longevity of other primary cells by production of corresponding growth factors. To test the dynamic behavior of cells on the membranes, an organ-on-chip (OOC) device has been developed with human umbilical endothelial cells (HUVECs) seeded on the membrane. The hydraulic resistance of the cellular barrier on the membrane has been quantified for real time trans-endothelial pressure (TEP) 20 cmH2O at 37 degree C and with living cells after 1 day and 3 day of post seeding. Results suggests this kind of polymeric scaffolds can be useful in future as an in vivo patch to repair disrupted vessels

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Folstad, Kristin. "Optimal operating strategies of the micro-CHP for improved interaction between the electrical and thermal demand and supply". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elkraftteknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26082.

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The research center of Zero Emissions Buildings (ZEB) has a goal of eliminating the greenhouse gas emissions associated with all phases of building development and use. This is achieved through more sustainable building construction and more efficient energy use. The Norwegian government has a similar goal of achieving zero energy buildings as a standard by 2020. This has led to proper investigation in technological solutions that can help to achieve these goals. In a net-ZEB perspective, combined heat and power (CHP) is considered as a potential energy supply solution for buildings. CHP is seen as an emerging technology which has the potential to reduce primary energy consumption and the associated greenhouse gas emissions. This is achieved through concurrent production of electricity and heat using the same fuel. However, since the thermal output of CHP is substantially larger than the electrical output, the potential offered by CHP systems depend on their suitable integration with the thermal demand of the building. In this thesis, a simulation model is used to investigate the performance of a CHP system compared to a conventional gas boiler system in a multi-family building that complies with the Norwegian building norm, TEK10. Different operational strategies are applied to the CHP model to investigate its optimal integration in domestic dwellings. Analyzing the simulation results indicates that the CHP system gives primary energy savings in all operational strategies, but operating the system in follow thermal mode represents the greatest savings. Applying load management resulted in further savings, and the fuel efficiency did increase, achieving a value of 75.1% on a higher heating value (HHV) basis. The CHP device is more capable of covering the electricity demand as peaks are shaved. This implies that CHP is better suited for buildings with stable electricity and heat demand. Electric demand following operation did however result in poorer primary energy savings and the corresponding CHP efficiency did decrease due to poorer heat recovery efficiency and frequent part load operation. Using renewable upgraded biogas as fuel in thermal following mode did result in the highest primary energy savings. Primary energy consumption was reduced by 34.3%, and the corresponding system efficiency based on primary energy was 70.7% on a HHV basis. From an environmental perspective, it has been found that the CHP system is more favorable when the CO2-emission factor for electricity is high. This is due to the reduction in electricity imports from the grid, and the part substituted electricity covered by the electricity exports from the CHP system. The greatest reduction in grid imports was seen when the CHP-device was set to follow the electrical demand of the building without restriction in thermal surplus. The CHP was able to cover 88.27% of the electricity demand, but the system efficiency decreased as significant amounts of heat was wasted due to overproduction. The highest amount of exports was seen when load management was implemented in thermal demand following mode, and represented 76.61% of the produced electricity. Using the current CO2-emission factor for the UCPTE electricity mix, a reduction in CO2 emissions was seen for all CHP configurations. The use of renewable fuel resulted in the greatest savings, and emissions were reduced by 71.91% compared to the gas boiler, representing a tremendous reduction. The use of natural gas as fuel resulted in significantly lower savings. The best case achieved a 26.58% reduction compared to the reference system. When using the net-ZEB definition, only CHP fuelled on renewable fuel did achieve CO2-savings. This questions the environmental viability of today’s CHP systems as the CO2-emission factor for electricity is expected to decrease over the coming years due to an expected increase in use of renewable fuels. Further research should therefore be done in order to enable an efficient CHP technology based on renewable fuels. This will decrease the emissions significantly, making CHP more competitive.

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Verit, Isabel. "Micro-Usinage par laser femtoseconde : Fabrication d'une microfibre glomérulaire perfusée". Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0159.

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Le nombre de patients en attente sur la liste de transplantation d'organe est croissant dû notamment à une augmentation de la durée de vie. L'ingénierie tissulaire, dans une optique de remplacement d'organes pourrait être une alternative à ce problème de pénurie d'organes. Cependant, la création d'un organe entier par ingénierie tissulaire est limitée par la complexité de son organisation et la vascularisation des tissus créés. La vascularisation permet en effet d’apporter l'oxygène et les nutriments nécessaires aux cellules et d'éliminer les déchets qu'elles génèrent. Sans vascularisation, les cellules ne peuvent survivre et nécrosent.Ce projet de thèse est un partenariat entre le laboratoire français BioTis - INSERM U1026 et le centre technologique d'optique et laser ALPhANOV autour de la bio-ingénierie tissulaire. L'objectif est de développer un procédé de fabrication et d'usinage pour créer un modèle de microfibres glomérulaires perfusables. Des microfibres cellulaires ont été réalisées au sein du laboratoire BioTis. Elles sont composées d’un cœur d’hydrogel de collagène et d’une paroi externe bicellulaire modélisant la barrière de filtration rénale. L’originalité de ce travail repose ensuite sur la création d’une lumière interne, à l’aide d’un faisceau laser à impulsions ultracourtes. Inspiré des procédés industriels d’usinages intravolumiques de matériaux transparents, les impulsions ultracourtes sont ici fortement focalisées dans le cœur de collagène pour créer un canal intravolumique via un phénomène de cavitation à l’intérieur des fibres sans impacter la couche externe de cellules
The demand for organ transplantation has rapidly increased during the past decades due to the increased incidence of vital organ failure and the greater improvement in post-transplant outcome. However, the unavailability of adequate organs for transplantation to meet the existing demand has resulted in major organ shortage crisis. Today, the emergence of regenerative medicine and more particularly, tissue engineering, appears as the best opportunity to effectively regenerate functional tissues and organs. However, these approaches face the 3D architectural complexity of a real organ’s system. More particularly, one of the most challenging issues when engineering tissues is the lack of an efficient method to produce blood vessel systems — the vascularization. Without nutrients and oxygen supply, cells die, and engineered tissues show cell necrosis.This project is a collaboration between the French laboratory of tissue engineering BioTis – INSERM U1026 and the technological centre in optics and lasers ALPhANOV. The aim of this project is to develop a model of perfusable glomerular microcapillary that would mimic glomerular filtration. Microfibres was crafted in the BioTis lab with a core made of collagen hydrogel and a peripheric cell bilayer. This thesis focuses on the creation of a channel within the collagen core using femtosecond laser processing. Following the principle of industrialized intra-volume laser microprocessing of transparent materials, ultra-short laser pulses were strongly focused inside collagen hydrogel to induce the formation of a channel through cavitation phenomena without affecting the cell bilayer

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Werme, Jonas. "SECURITY AWARENESS THROUGH MICRO-TRAINING : An initial evaluation of a context based micro-training framework". Thesis, Högskolan i Skövde, Institutionen för informationsteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-10749.

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Phishing is a growing problem. Most current research about mitigating damages from or preventing such attacks is aimed at either preventing users from receiving and clicking links to fraudulent sites, or using indicators to show the user whether a visited site can be trusted. This thesis focuses on education of the user for situations where a link has already been clicked, raising awareness of available security indicators. This is done using an implementation of a framework developed by Dr. Marcus Nohlberg to provide micro-training within and about the context of e-commerce. An experiment using two groups of students, and four webshops created for the experiment, show positive results for the group receiving micro-training from the framework implementation

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Ku, Mui Sing Alice. "Workplace learning and interaction between individual identity, social relations and organizational environment : a comparative study between micro and small companies". Thesis, University of Leicester, 2012. http://hdl.handle.net/2381/11031.

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This study aims to investigate how individual identities, social relations and organizational strategies interact in the workplace learning of SMEs. The practices within the micro and small financial consulting companies in Hong Kong are compared. The influence of the owner-manager, learning culture, power and emotion on learning will also be investigated. A qualitative approach was adopted and semi-structured interviews accompanied with observation and document analysis were used. A total of thirty respondents from 2 small and 3 micro companies were involved in this study. All companies were subsidiary of two mother companies. Data from interviews, observation and documents was analyzed. An inclination towards formal learning at organization level was found. However, both formal and informal learning were seen as central to professional development. Multi- dimensional Identity evolved as career and life span change and this impacted on the learning behavior of respondents. Learning helped to build a better professional image. Learning also occurred when respondents participated within a community. The influence of the owner on learning within the firm changes with the formation process and company size. Small firms, with greater formalization and specialization use formal training more frequently than the micro firms. In particular, externally-provided formal training is used to supplement in-house training. Power distribution is affected by size and formation process. Also emotion affects learning from individual to company levels. Ultimately, the findings support the conclusion that the factors influencing the small firm's approach to learning are highly complex. Specifically, social relations at group level in combination with subjective individual dispositions and the structural organizational environment are implicated in orientating the small firm towards particular types of learning. Workplace learning cannot be properly understood without an appreciation of these multi-level influences and the interaction between them. Furthermore, the findings indicate that preferred modes of learning in some types of small firm may be of a more formal kind than the literature on learning in small firms has sometimes assumed.

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Burgess, Michael. "The 'whole of the wall' : a micro-analytic study of informal, computer-mediated interaction between children from a marginalised community". Thesis, University of Newcastle upon Tyne, 2016. http://hdl.handle.net/10443/3318.

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As a prominent symbol of the free-market, liberationist approach to International Development (ID), the Self-Organised Learning Environment (Mitra, 2006) has been presented as a bona-fide revolution in primary education provision, a means by which the global poor can finally gain a legitimate foothold in modernity with nothing more than a computer and an internet connection (Tooley, 2006). Naturally, the notion of a credible, teacher-less environment characterised by a spontaneous and coherent pedagogy of enquiry is a remarkable yet, highly emotive hypothesis with potential consequences far beyond the domain of ID. Indeed, a review of the associated literature attributes a raft of learning claims to the SOLE, not to mention supplementary social and psychological benefits (Mitra 2012). On the other hand, an overtly foundational approach to SOLE research is neither supported by an empirical study of participant interaction nor a coherent definition of learning, presenting the participants as nothing more than `ghosts with a machine`. On the understanding that self-organisation can only truly exist as an emergent practice, where talk-in-interaction is presumed to reside at the heart of social order (Boden & Zimmerman, 1991), this thesis represents a detailed micro-analysis of SOLE participation among children from a marginalised community resident in Boyacá, Colombia. In direct contrast to a large-scale, etic approach to educational research founded on a priori concepts, testing, statistics and generalisation (Mitra, 2006), the learning space is reconceived as a distinctly intimate, Community of Practice (Wenger, 2000). In which case, computer-mediated activity is characterised relative to an interactional paradigm (Hutchby, 2001) and Page 3 the canonical features of mundane conversation, including; turn-taking, repair and topic management (ten Have, 1999). To begin with, it is argued that SOLE interaction can be arranged in terms of the following series of interrelated routines: Entry; Challenge; Search; Tutorial; Evaluation; Outage; Fly-Solo. As Sacks anticipated (Silverman 1998), micro-analysis reveals that participation and computer-mediated multi-activity is broadly consistent with the exigencies of context. Self-organisation then is shaped by the social realities of identity and the seemingly paradoxical features of group belonging (sharing) and individual autonomy (control) manifest in practices of opposition, assessment and insult (Goodwin & Kyratzis, 2009; Corsaro, 2005). Secondly, the SOLE organisational and learning structure is distinctly intra-personal and autocratic in nature. Thereafter, peer-to-peers relations are subject to situated distributions of epistemic authority coupled with unilateral demonstrations of the deontic equivalent. Moreover, Mitra’s idealised representation of a learning environment free from institutional/ideological interference i.e. outdoctrination, is challenged by a conspicuous, politicisation of the SOLE by the participants themselves. Thirdly, the dyad is the principle mode of operation where participants orient towards the computer as a limited resource/object rather than an active participant or product of social construction. Forthly, interaction is broadly consistent with the principal features of canonical talk where accountability is sustained through a combination of linguistic and para-linguistic activity (Atkinson & Heritage, 1984). To this effect, participant intersubjectivity is produced and sustained through mutually supportive acts of mediated coherence relative to a recognisable series of emergent procedures, namely: dispute; action-listing; effectuated repair; reciprocal exchanges; place-saving. Finally, the Page 4 detailed linguistic features of interaction point to an object-oriented, `mobilising` speech-exchange system operating directly at the interface between talk and social action. Whilst the precise flow of interaction is virtual-activity dependent, the system is consistently characterised by abbreviated forms of talk, most conspicuously; deictic reference, directives and response cries supplemented throughout by embodied gesture/metanarrative. Irrespective of these linguistic shortcuts, not to mention limitations of computer affordance i.e. ambivalence, overload and diversions, the general absence of breakdown suggests a degree of communicative competence between the participants. In which case, notions of situated learning and knowledge are not so much cognitive and mechanical in nature but distinctly social and interactional (Hutchby & Moran-Ellis, 2001) with the principal aim of CoP assimilation: learning is not so much related to the acquisition of arbitrary, content-centric knowledge, as it is about play, identity and situated competency as part of an emergent social practice within an unfamiliar mediated context In conclusion, it is argued that a liberationalist approach to ID research and education is definitively and inexorably deterministic in nature. In the absence of interactional data, Mitra is seemingly obliged to co-opt the principle symbols of an alternative, social-cultural paradigm i.e. collaboration, agency, democracy, equality, criticality, in order to add intellectual ballast to the otherwise empty claims of self-organisation i.e. a `Trojan Mouse` approach to social and educational change (Selwyn, 2011). In broader terms of development policy, the issue of authentic representation is viewed as a priority. Thereafter, the study Page 5 recommends a context-sensitive paradigm of ID research as a meaningful supplement to the prevailing logo-centric orthodoxy. Consistent with the rhetoric of post-colonialism, emphasis is shifted to a post-structural sociology (Heritage, 1984) and educational curriculum (Slattery, 2006) supported by a counter-balancing emic approach to research i.e. micro-ethnography, one that seeks to give authentic voice not only to SOLE participants but to the multitude living extreme poverty as a relentless, day-to-day reality.

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Annovazzi, Alicia. "Contribution à l'étude - interaction laser-matière à différentes pressions résiduelles : Application au procédé micro-fusion laser sur lit de poudre". Thesis, Bourgogne Franche-Comté, 2020. http://www.theses.fr/2020UBFCA024.

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Le procédé de micro-fusion sur lit de poudre par faisceau laser (LBM) et par faisceau d’électrons (EBM) sont deux procédés de fabrication additive permettant la réalisation de pièces métalliques. L’intense densité d’énergie fournie par ces deux sources permet la fusion locale de la matière formant ainsi un bain liquide, qui se solidifie après refroidissement. Ce changement d’état, qui se déroule sur des temps très courts, induit de complexes phénomènes thermodynamiques. Chacun de ces procédés offre des avantages qu’il serait intéressant de combiner. De ce fait, une combinaison des deux technologies a été investiguée. Le procédé EBM nécessitant un vide poussé dans l’enceinte de travail, l’enjeu de cette thèse repose donc sur l’étude de la fusion laser à faible pression environnante. Outre la combinaison recherchée, la fusion laser sous vide peut s’avérer intéressante dans l’amélioration de la santé matière des pièces, en particulier pour des matériaux sensibles à l’oxygène. Cependant, une nette diminution du rendement du procédé est observée. Ce travail de thèse s’articule en deux parties : a) En premier lieu, une étude expérimentale de la fabricabilité d’échantillons à différentes pressions a été réalisée. Pourdes paramètres de fabrication identiques, il en ressort qu’une diminution significative de la densification des échantillons est obtenue lors de la fabrication à faibles pressions. Les paramètres densité d’énergie volumique et vitesse de déplacement du laser ont dû être alors adaptés en fonction de la pression environnante utilisée. b) La seconde partie a été consacrée à l’explication des mouvements du bain liquide qui ont évolué en fonction de la pression résiduelle. A cet effet, une caméra rapide a permis de montrer les importantes instabilités présentes dans le lit de poudre par la zone de dénudation, et le bain liquide par sa morphologie, pour certains paramètres laser. Ces phénomènes ont été d’autant plus observés pour des pressions résiduelles inférieures à 30 mbar. Enfin, le pré-frittage du lit de poudredans le but d’effectuer un recuit "in-situ" des matériaux étudiés, a montré un effet bénéfique lors de l’interaction laser-matière sous vide. Une amélioration de la qualité de fusion et une augmentation du rendement de fabrication ont été alors démontrées
The laser beam melting (LBM) and electron beam melting (EBM) processes are two additive manufacturing technologies allowing the production of metallic parts. The intense energy density provided by the power supply is sufficient in order to melt the material creating a molten pool, and will solidify after cooling. This change of phase which takes place in a very short time, induced complexthermodynamics phenomena. Each of the processes offer advantages that could be interesting to be combined. Hence, a combination of the two technologies has been investigated. The EBM process requiring a rough vacuum in the work chamber, the issue of this work is based on the study of the laser melting at low pressure. Besides the intended combination, the selective laser melting under vacuum pressure can be attractive with the aim of improving the material integrity, in particular on the oxygen-sensitive materials. However, a clear decrease of the process efficiency has been observed. This work includes two parts: a) Firstly, an experimental study of samples fabricability at different pressures conditions is observed. For the same manufacturing parameters, a significant decrease of samples densification is observed in rough vacuum. The parameters volumetric energy density and the laser displacement speed have to beadapted in function of the chamber pressure. b) The second part is an attempt to explain the molten pool motion which change depending on the pressure. This can be achieved with a fast cam allowing the observations of strong instabilities in the powder bed with the denudation zone, and the molten pool with the morphology, for specific laser parameters. These phenomena are more important for residual pressures under 30 mbar. Then, a powder bed pre-sintering for the purpose of ”in-situ” annealing of the materials studied, has shown the beneficial effect during the interaction laser-powder under vacuum. Improvement melt quality and increased manufacturing efficiency have beenachieved

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Lundin, Maria, e Lena Kanstrup. "Method for detection of sleepiness : - measurement of interaction between driver and vehicle". Thesis, Linköping University, Department of Mechanical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7714.

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As more and more people conduct vigilance-based activities at times other than the traditional daytime work hours, the time utilization will continue to escalate in the next century and will further increase the risks of sleepiness-related accidents.

This project, which is commissioned by Scania CV AB, is to nvestigate the potential of a method for sleepiness detection belonging to esium AB. Our objective is to examine whether Scania CV AB should continue with the investigation of the patent method, and in that case, which patent parameters, that indicate sleepiness, should be more closely inquired. The purpose with the method of patent is to discover a sleepy driving behaviour. This method is based on the interaction that appears between the driver and the vehicle. The interaction consists of small spontaneous corrections with the steering wheel that in this report is called micro communication. How well the interaction is functioning can be measured in degree of interaction, which shows how well the driver and the truck interact with each other. The interaction between the driver and the vehicle is in this report looked upon as answers and questions with a certain reaction time, which appears with a certain answered question frequency. The differences in the signal’s amplitudes are measured in variation in amplitudes.

Experiments to collect relevant signals have to be conducted in order to investigate the potential with the method of the patent. It is eligible to collect data from a person falling asleep, which implies experiments conducted in a simulator. The experiments are executed in

a simulator, one test when they are alert and one when they are sleep deprived. Tests are also executed in a Scania truck. The purpose with these experiments is to collect data of the subject’s normal driving pattern in a truck and to investigate if it is possible to obtain

acceptable data in a truck.

The sleepiness experiments have indicated that the micro communication takes place in a frequency range of 0.25 to 6.0 Hz. The variables that have been found to detect sleepiness with high reliability are the reaction time and the degree of interaction presented in spectra.

The validation experiments have shown it is possible to collect exact and accurate data from the lateral acceleration and the steering wheel torque. But, there is more noise in the signals from truck then there is in the signals from the simulator.

This method for sleepiness detection has, according to the authors, a great potential. However, more experiments have to be conducted. The authors suggest further sleepiness experiments only conducted during night time. The subjects are sufficiently alert in the beginning of the test to receive data from normal driving behaviour. Physiological measurement could be interesting to have by the side of the subjective assessments as an additional base for comparison.

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Benmeziane, Karim. "Etude d'une source ECR d'ions H- pour accélérateurs de forte puissance". Paris 11, 2004. http://www.theses.fr/2004PA112041.

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Après une revue des différentes sources d'ions H-ainsi que des méthodes permettant l'amélioration de leur production, la première parti de cette thèse est consacrée à l'étude et la caractérisation de la source ECR. Nous tentons d'expliquer les raisons du faible courant d'ions H-produit par cette source (5 [mu]A). La principale raison est le fort couplage entre les électrons et l'onde HF conduisant à un chauffage donc à une énergie électronique trop importante. A l'issue de ce diagnostic, il a été décidé d'utiliser la source ECR comme source primaire d'électrons destinés à être injectés dans une seconde enceinte. Deux études théorique (PIC-MCC 2D-fluide) et expérimentale sont alors effectuées sur le développement de cette source " hybride ". Le code de calcul aide à la compréhension des phénomènes physiques se produisant dans la source. Une énergie d'injection optimale à 40 eV ainsi qu'une distance d'interaction efficace des électrons avec le plasma d'environ 3 cm ont notamment été mises en évidence. Sachant qu'il est très difficile de transporter un faisceau intense d'électrons de faible énergie, nous avons choisi de séparer la chambre plasma par une grille polarisable. Une vérification expérimentale d'une distance efficace comprise entre 2 et 3 cm a été faite ainsi qu'une nette amélioration du courant extrait. Certaines des méthodes supposées accroître les performances de la source ont été essayées avec plus ou moins de succès, d'autres ont volontairement été mises de coté. Au bout du compte, le courant d'ions H- a gagné un facteur 300 depuis la mesure des premiers ions négatifs; il est passé de 5 [mu]A à 1,4 mA. La source offre ainsi un fort potentiel d'évolution
After a review on the H- ion source and methods allowing the enhancement of their production, the first part of this thesis is dedicated to the ECR ion source diagnostic. We explain the reason why the H- current is so low with such sources (5[mu]A). It is manly due high energy electrons created by a very efficient coupling between the microwave and the electrons. So, it has been decided to use the ECR ion source not as an H- ion source but as an electron provider to inject into a separated chamber. Theoretical and experimental investigations have been done. Then, a hybrid PIC 2D MCC 3D fluid code has been developed. Its aim is to study the effect of an electron injection into a cylindrical gas chamber. Many results have been brought as well as the best injected energy and the electron penetration length efficiency. Thus, an injection of 40 eV electron beam in a length of 3 cm seems to be the most efficiency. This last point has been observed in the experiment which consists in the installation of a polarized grid in the plasma chamber to obtain the two separated chamber. Some methods supposed to increase the source performance have been tried and some have been blown out. Finally an enhancement of a factor 300 has been observed since all modifications. The H- ion current is now higher than 1,4 mA and a high potential of improvement is expected in the future for this new type of source

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Renaud, Guillaume. "Mesure de non-linéarités élastiques et dissipatives par interaction d'ondes acoustiques : Application à la quantification du micro-endommagement de l'os trabéculaire". Phd thesis, Université François Rabelais - Tours, 2008. http://tel.archives-ouvertes.fr/tel-00360281.

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Des micro-fissures sont générées dans le tissu osseux et résorbées par le remodelage
osseux. Une densité de fissures importante pourrait détériorer la résistance mécanique
osseuse (RMO). Cependant les causes et les conséquences sur la RMO d'une accumulation
du micro-endommagement osseux sont mal connues. De plus, aucune méthode non invasive
de quantification du niveau d'endommagement osseux existe aujourd'hui.
Dans ce contexte, une méthode de mesure acoustique, localisée et sans contact, basée
sur l'interaction non linéaire (NL) entre une onde acoustique basse-fréquence (BF) et des
impulsions ultrasonores (US) a été développée. Les impulsions US sont émises à une cadence
de tir environ 10 fois supérieure à la fréquence de l'onde BF. Le milieu est alors sondé à
différents états de contrainte tri-axiale, en compression et traction. Les variations du temps
de vol et de l'amplitude (ou de l'énergie) US rendent compte des effets NL acoustiques
respectivement élastiques et dissipatifs. Les effets NL acoustiques élastiques et dissipatifs
augmente généralement avec le niveau d'endommagement.
Après une validation dans l'eau et des solides non endommagés, des mesures dans des
matériaux fissurés et granulaires ont montré la sensibilité de la technique à la présence de
fissures et de contacts entre grains. Enfin son application à l'os trabéculaire du calcanéum a
montré que la zone de faible porosité pouvait produire de fortes non-linéarités acoustiques.
Pour des échantillons endommagés in vitro par fatigue en compression et par compression
quasi-statique, l'amplitude des non-linéarités acoustiques a montré une bonne corrélation
avec l'observation histologique du niveau d'endommagement.

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Beldjoudi, Nadir. "Interaction ondes electromagnetiques-polymeres : comportement des resines epoxydes sous rayonnement micro-onde continu ou pulse, application aux composites epoxyde/poudre d'argent". Toulouse 3, 1988. http://www.theses.fr/1988TOU30006.

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Nominé, Alexandre. "Micro-décharges en milieu électrolytique aqueux et leur interaction avec les matériaux : le cas du procédé d'oxydation par plasma électrolytique (PEO)". Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0154/document.

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L’Oxydation par Plasma Electrolytique (PEO) est un procédé de traitement de surface des alliages métalliques légers (Al, Mg, Ti) qui permet de faire croître des couches protectrices d’oxydes épaisses et dures sur ces matériaux. Pour dépasser les limites de l’anodisation, le procédé PEO repose sur la génération de micro-Décharges anodiques résultant du claquage de la couche diélectrique dans un électrolytique aqueux sous l’effet d’une densité de courant ou d’une différence de potentiel élevées (typ. 20 A/dm2 ; 700 V). Les objectifs de ce travail sont d’une part d’étudier les caractéristiques des micro-Décharges (composition chimique, densité et température électronique) et leur comportement macroscopique (conditions d’amorçage, densité surfacique, taille, durée de vie), et d’autre part de corréler ces études aux mécanismes de croissance des couches d’oxydes dans différentes conditions électriques (forme du courant bipolaire pulsé) et de composition d’électrolytes alcalins. Ces études couplées ont permis notamment de mettre en évidence que le passage en régime d’autorégulation (précédemment identifié) s’accompagne de la croissance d’une couche spongieuse, vraisemblablement amorphe, autour et dans les fissures de structures composées d’alumine cristallisée et résultant des claquages diélectriques. De même, la caractérisation de couches traitées PVD + PEO a conduit à améliorer la compréhension de certains mécanismes de claquage intervenant dans le procédé PEO, et en particulier les processus à l’interface couche d’oxydes - substrat. Enfin, une étude spécifique des micro-Décharges cathodiques (inhabituellement observées en PEO) a conduit à proposer des mécanismes de claquage de la couche diélectrique durant cette demi-Période cathodique du courant. Il a en outre été montré que, bien que l’alternance négative du courant soit nécessaire pour améliorer la croissance des couches d’oxydes, les micro-Décharges cathodiques ont un effet néfaste sur celle-Ci. Il est ainsi nécessaire de contrôler la forme d’onde du courant appliqué afin d’éviter la génération de telles décharges
Plasma Electrolytic Oxidation (PEO) is a surface treatment of light metallic alloys (e.g Al, Mg, Ti) that makes possible to grow thick and hard oxide protective coating on those materials. To overcome the limitations of anodizing the PEO process takes benefit of anodic micro-Discharges resulting from the dielectric breakdown in an aqueous electrolyte under a high applied current density or voltage (typ. 20 A/dm2; 700 V). Therefore this work aims first at studying both the macroscopic parameters (breakdown conditions, surface density, lifetime, size) of such micro-Discharges and their behavior, and second to correlate these studies to the growth mechanisms of the oxide coatings within various electrical (applied current waveform) conditions and alkaline electrolyte composition. These coupled studies allowed us to evidence that the transition from arc regime to soft regime (previously determined) corresponds to the growth of a loose spongy silicon-Rich phase which is likely amorphous, inside and around cracks of the pancake structures issued from the dielectric breakdown and composed of crystalline alumina. Meanwhile, analyses of combined PVD + PEO coatings lead us to improve our understanding of some breakdown mechanisms occurring during the PEO process, with a particular attention to the phenomena at the coating-Substrate interface. Finally, a particular study of cathodic micro-Discharges (unusually observed in PEO) allowed us to propose breakdown mechanisms of the dielectric layer during that negative half-Period of the current. Besides it has been shown that those cathodic micro-Discharges are detrimental to the layer growth though the cathodic half-Period of the current is mandatory to improve the coating growth. It is therefore necessary to manage the current waveform to avoid creating such detrimental discharges

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Beldjoudi, Nadir. "Interaction ondes électromagnétiques-polymères, comportement des résines époxydes sous rayonnement micro-onde continu ou pulsé application aux composites époxyde/poudre d'argent /". Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37611696b.

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Renaud, Guillaume. "Mesure de non-linéarités élastiques et dissipatives par interaction d'ondes acoustiques : application à la quatification du micro-endommagement de l'os trabéculaire". Thesis, Tours, 2008. http://www.theses.fr/2008TOUR4012/document.

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Des micro-?ssures sont générées normalement dans le tissu osseux et résorbées par le remodelage osseux permanent. Une densité de ?ssures trop importante pourrait détériorer la résistance mécanique osseuse (RMO). Cependant les causes et les conséquences sur la RMO d’une accumulation du micro-endommagement osseux sont mal connues. De plus, aucune méthode non invasive de quanti?cation du niveau d’endommagement osseux existe aujourd’hui. Dans ce contexte, une méthode de mesure acoustique, localisée et sans contact, basée sur l’interaction non linéaire (NL) entre une onde acoustique basse-fréquence (BF) et des impulsions ultrasonores (US) a été développée. Les impulsions US sont émises à une cadence de tir environ 10 fois supérieure à la fréquence de l’onde BF. Le milieu est alors sondé à di?érents états de contrainte tri-axiale, en compression et traction. Les variations du temps de vol et de l’amplitude (ou de l’énergie) US rendent compte des e?ets NL acoustiques respectivement élastiques et dissipatifs. Les e?ets NL acoustiques élastiques et dissipatifs augmente généralement avec le niveau d’endommagement. Après une validation dans l’eau et des solides non endommagés, des mesures dans des matériaux ?ssurés et granulaires ont montré la sensibilité de la technique à la présence de ?ssures et de contact entre grains. En?n son application à l’os trabéculaire du calcanéum a montré que la zone de faible porosité pouvait produire de fortes non-linéarités acoustiques. Pour des échantillons endommagés in vitro par fatigue en compression et par compression quasi-statique, l’amplitude des non-linéarités acoustiques a montré une bonne corrélation avec l’observation histologique du niveau d’endommagement
Micro-cracks are normally generated in bone tissue and resorpted by permanent bone remodeling. A high crack density could a?ect bone strength. But the causes and consequences on bone strength of a microdamage accumulation are badly understood. Moreover no technique is available for noninvasive assessment of the level of bone damage in vivo. In that context, an acoustical method was developed for localized and non-contact measurement of elastic and dissipative nonlinearities, based on the interaction between a low-frequency acoustic pump wave and ultrasound probing pulses. The ultrasound pulses are emitted with a repetition frequency 10 times higher than the low frequency of the pump wave. The medium is thus probed in di?erent states of triaxial stress, successively in tension and in compression. The ultrasound time of ?ight and amplitude (or energy) modulations give access to nonlinear elasticity and dissipation, respectively. The amplitude of acoustic nonlinearities generally increases with the level of damage in materials. After validation in water and undamaged solids, measurements were conducted in cracked and granular media and showed a good sensitivity of the method to the presence of cracks and contacts between grains. Finally its application to calcaneus trabecular bone showed that the low-porosity region can exhibit high acoustic nonlinearities. Furthermore, for mechanically damaged samples, either in compressive fatigue or in quasi-static compression, the amplitude of acoustic nonlinearities were well correlated with the level of damage observed by histology

38

Lin, Yuan. "Modeling of dielectrophoresis in micro and nano systems". Doctoral thesis, Stockholm : Mekanik, Mechanics, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4784.

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Taylor, Roberta E. "Being clouds, pulling teeth and using their breadloaves : a multimodal micro-analysis of instantiations of child-to-child interaction in classroom contexts". Thesis, University of Sheffield, 2011. http://etheses.whiterose.ac.uk/14655/.

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This study examines the ways in which children communicate and collaborate with one another whilst working on curriculum tasks in an educational setting. It uses an approach to methodology founded on Linguistic Anthropology and Linguistic Ethnography and informed by a social-semiotic theory of communication, drawing upon field notes and video-recorded data from a class of nine and ten year olds at a Sheffield primary school. A framework informed by sociolinguistic theory and multimodal analyses of communication has been devised to analyse the data in such a way that the many and varied modes of meaning-making employed by the children are considered. The purpose of the study is to gain a deeper understanding of the ways in which children creatively employ semiotic resources in their face-to-face spontaneous interactions. The main findings of the study are that modes of meaning-making are integral to the communicative activity and work in coordination with each other. Features which have been noted in linguistic studies of interaction can be seen in this multimodal study and could be classed as features of multimodal communication rather than linguistic features. In addition, child-to-child classroom meaning-making is intersubjective and collaborative. Knowledge can be presented through any chosen mode and can be developed collaboratively through multiple modes. The study has implications for pedagogy in that educationalists need to be aware of the multimodal nature of children's interactions, recognise the value of the semiotic work of pupils and ensure opportunities for meaning-making using multiple modes are planned for. The implications for future research are that methodological approaches need to take account of the use of all modes in interactions in order to gain a thicker description of what is taking place than could be achieved with a language-dominant approach.

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Chahat, Nacer. "Antenne, propagation et interaction avec le corps pour les applications de type réseaux corporels sans fil en micro-ondes et en millimétrique". Rennes 1, 2012. http://www.theses.fr/2012REN1S079.

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Grâce aux progrès récents effectués dans la conception de réseaux intelligents et dans les techniques de miniaturisation des objets communicants, les réseaux sans fil à proximité ou centrés sur la personne concentrent aujourd'hui toutes les attentions grâce à leur large éventail d'applications (sportives, médicales, militaires, etc. ). Cet intérêt croissant pour les applications BAN (Body Area Networks) et PAN (Personal Area Networks) se traduit aujourd'hui par l'apparition de capteurs sur textiles facilitant l'intégration de ces dispositifs sur le corps et limitant ainsi l'encombrement sur ce dernier, mais aussi par la nécessité de développer des solutions capables d'assurer un débit de transmissions sans fils très élevé (vidéos HD). Ces travaux de thèse ont deux objectifs principaux. Le premier consiste à développer des antennes sur textiles pour lesquelles une attention particulière est accordée sur l'interaction avec le corps de l'utilisateur. L'influence du corps humain est primordiale dans l'évaluation de l'efficacité des capteurs et des performances globales du système. Le second consiste à développer un réseau corporels en bande millimétrique (57-64 GHz) permettant de réduire significativement la taille des capteurs, d'augmenter les niveaux d'interférence et de sécurité, et enfin, d'atteindre des débits de transmission sans précédent en comparaison avec les réseaux existant en plus basse fréquence
Recent progress in miniaturization of communicating devices and design of smart networks has triggered increased interest to body area networks (BAN) having a very strong potential for near future applications including military, personal healthcare, sport, space, entertainment, smart home, etc. This increasing attention to BAN and PAN (Personal Area Networks) applications has led to the development of textile sensors that can be easily integrated into clothes and to the buildup of high-data-rate wireless devices. The PhD thesis project has two main objectives. First, several microwave textile antennas have been optimized and fabricated to evaluate the interaction with the human body. The impact of the human body on the antenna performance is of great importance since it can directly impact the efficiency of on-body devices and global performances of the system. The power absorption in the body was also studied using realistic body models with different morphologies. Second, the unlicensed 57-64 GHz band have been studied in the wireless BAN context since it provides several advantages compared to microwave BAN. In particular, very high data rates can be reached (up to 5 Gb/s) whilst providing high level of security and low interference with adjacent networks. Besides, the on-body devices are much smaller at millimeter waves compared to those operating at microwaves

41

Damiani, David. "Interaction laser-materiaux : applications au dépôt de couches minces supra-conductrices à haute température critique et au micro-usinage de divers materiaux". Limoges, 1991. http://www.theses.fr/1991LIMO0125.

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Ce travail concerne l'etude de l'interaction entre le rayonnement d'un laser uv et un materiau et comporte trois parties: la premiere est relative a la description simple par un modele des mecanismes regissant l'interaction entre le rayonnement d'un laser de forte puissance (>10#8 w/cm#2) et une cible metallique ou ceramique. Ce modele permet de calculer les caracteristiques de l'ecoulement dans la phase gazeuse et de comparer les vitesses calculees avec celles mesurees par spectroscopie optique resolue en temps. La deuxieme partie est consacree au diagnostic du panache plasma cree lors de la pulverisation par un laser excimeres a krf emettant a 248 nm d'une cible supraconductrice massive type ybacuo ou bisrcacuo par spectroscopie optique et spectrometrie de masse. Nous exposons les resultats obtenus sur la composition du plasma, la vitesse d'ejection des particules, leur cinetique de creation disparition et leur distribution spatiale en fonction de l'atmosphere ambiante et la fluence laser. La troisieme partie concerne l'obtention de couches minces supraconductrices a haute temperature critique par pulverisation laser uv. L'influence de divers parametres (pression d'oxygene, fluence laser, temperature du substrat, epaisseur du film, recuit) sur la qualite des couches obtenues est mise en evidence. Enfin, nous exposons quelques resultats sur le micro-usinage par laser uv de divers materiaux (metaux, polymeres, ceramiques) montrant l'interet de cette technique par rapport aux techniques classiques ou meme a l'usinage par laser yag a 1. 06 microns

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Just, Xavier. "Interaction entre arc et matière granulaire lors d’une coupure ultra-rapide dans un fusible". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAI080/document.

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Ce travail s’inscrit dans le projet Fusible Ecologiquement et Economiquement Efficace destiné à la protection des onduleurs à commutation en tension (FE2E) porté par la société Mersen. Les fusibles étudiés sont constitués de lames d’argent noyées dans du sable de silice aggloméré. Lors d’un court-circuit, un arc électrique apparaît au niveau de rétrécissements dans les lames d’argent (« sections réduites »). Les coupures ultrarapides (moins de 100 microsecondes) ont été très peu étudiées. La structure formée après coupure (fulgurite) est constituée d’un canal d’arc entouré de silice fondue. C’est sur ces structures que cette étude a été réalisée.Après une étude bibliographique, un travail expérimental a été mené pour comprendre comment l’énergie de l’arc est absorbée par la matière. Des observations de coupures par radiographie in situ réalisées à l’ESRF ont permis d’établir des liens entre les phénomènes de création de fulgurite et les mesures électriques. Des observations et des mesures ont été réalisées. Elles ont conduit à établir des corrélations entre le volume, la nature et la structure de la masse isolante générée lors de la coupure et les caractéristiques électriques de l’arc. Les mesures ont en particulier permis d’obtenir des dimensions et des formes caractéristiques des zones affectées thermiquement lors des coupures aux grands di/dt.Grâce à ces informations, des modèles numériques ont été développés, avec pour objectifs de décrire la formation du canal d’arc et d’estimer l’effet du confinement de l’arc par le sable de silice. Des géométries 1D axisymétriques puis 2D ont été utilisées. L’arc électrique était considéré comme une densité de puissance et le sable comme un milieu continu équivalent. Deux cas extrêmes ont été testés, l’un dans lequel la matière vaporisée est confinée dans un canal d’arc fermé, l’autre dans lequel elle s’échappe instantanément. Cela a permis d’identifier les conséquences du confinement sur les phénomènes lors de la coupure.La corrélation entre modélisation et expérience a conduit à un modèle simple dont les résultats sont conformes aux mesures expérimentales et qui permettent de donner des éléments pour le dimensionnement des nouveaux fusibles. Les phénomènes à prendre en compte dans le futur ont été identifiés, comme la propagation de la silice liquide et l’écoulement du gaz dans le milieu granulaire et la formation de l’arc
This work is part of a project called Environmentally and Economically Effective Fuses (FE2E) driven by the Mersen company. The studied fuses are silver blades embedded in agglomerated silica sand. In case of short circuit, an electric arc appears in shrinked parts (“notches”) of silver blades. The structure formed after the cut (fulgurite) consists in an arc channel surrounded by amorphous silica. Extremely fast cuts (less than 100 microseconds) have been poorly studied.After a bibliographical review, an experimental work was performed to understand how the arc power is absorbed by the surrounding material. Power cuts observations using in situ radiography performed at the ESRF allowed to establish links between fulgurite formation phenomena and electric measurements. Observations and measurements led to correlations between volume, nature and structure of the insulating mass generated during the power cut and electrical characteristics of the arc. In particular, these measurements provided characteristic sizes and shapes for heat affected zones during power cuts at high di/dtNumerical models were developed on this basis for describing the arc channel formation and determining the role of silica sand containment. 1D then 2D axisymmetric geometries were used. The electric arc was considered as a power source and the sand as an equivalent continuous medium. Two extreme cases were tested: when the vaporized material was confined to a closed arc channel and when it escapeed immediately from the arc channel. The results helped identify the consequences of gas containment in the arc channel during power cut.Modeling vs experience correlations led to a simple model which gives information for optimizing new fuses. Some phenomena to be taken into account in future works have been identified, such as the liquid silica penetration and gas flow in the granular packing and the early stages of arc formation

43

Santos, Fabiana Borges Teixeira dos. "Corporate governance in economic development : a micro-macro interaction perspective for a new approach to the theory of the firm in developing countries". Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612437.

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Jia, Rongfang. "Dynamic Mother-Infant and Father-Infant Interaction: Contribution of Parents’ and Infants’ Facial Affect and Prediction from Depression, Empathy and Temperament". The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397809199.

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Nilsson, Rebecka. "Designing an Interactive Micro-Learning Application : A New Way to Learn Thermography". Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-451072.

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Micro-learning is a concept of small units of focused and condensed learning activities that can be performed on various devices. Micro-learning has turned out to be an effective approach to strengthen the long-term memory. This master’s thesis project explores the concept of micro-learning, how thermography can be taught using micro-learning, and how a micro-learning application can be designed to encourage learning of thermography. This project was done in collaboration with FLIR Systems AB that wants to develop their current training offer and investigate micro-learning as an alternative. The goal of this master’s thesis project was to design and test an interactive prototype of a micro-learning application to learn thermography. Semi-structured interviews were conducted in order to define the target group for the application, and the prototype was tested and evaluated by test participants from the target group. The user testing and evaluation showed that all test participants would use a micro-learning application for learning thermography if it was available on the market. Three out of four test participants would feel more motivated to learn thermography using a micro-learning application compared with other ways of learning.
Mikroinlärning är ett koncept bestående av små delar av fokuserade och komprimerade lärandeaktiviteter som kan utföras på olika enheter. Mikroinlärning har visats sig vara ett effektivt sätt för att stärka långtidsminnet. Detta examensarbete utforskar mikroinlärning som koncept, hur termografi kan läras ut med hjälp av mikroinlärning samt hur en mikroinlärningsapplikation kan designas för att främja lärandet av termografi. Detta projekt genomfördes i samarbete med FLIR Systems AB som vill utveckla deras nuvarande utbildningserbjudande och undersöka mikroinlärning som ett alternativ. Målet med detta examensarbete var att designa och testa en interaktiv prototyp av en mikroinlärningsapplikation för att lära sig termografi. Semistrukturerade intervjuer gjordes för att definiera målgruppen för applikationen och prototypen testades och utvärderades av testpersoner från målgruppen. Användartestet och utvärderingen visade att alla testdeltagare skulle använda en mikroinlärningsapplikation för att lära sig termografi om det fanns tillgängligt på marknaden. Tre av fyra testdeltagare skulle känna sig mer motiverade att lära sig termografi med hjälp av en mikroinlärningsapplikation jämfört med andra sätt att lära sig.

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Grébert, Arnaud. "Simulation numérique aux grandes échelles du contrôle de l'interaction onde de choc/couche limite au moyen de micro-générateurs de vortex". Thesis, Toulouse, ISAE, 2018. http://www.theses.fr/2018ESAE0046.

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L’interaction entre une onde de choc oblique et une couche limite turbulente (IOCCL) est unesituation fréquemment rencontrée dans le domaine des écoulements compressibles d’intérêtapplicatif. L’IOCCL est le siège d’instationnarités à basse fréquence qui engendrent d’importantesfluctuations de pression pariétale et cette thèse s’intéresse à l’étude de dispositifs de contrôle passifde type micro-générateur de vortex (mVG) pour réduire, voire supprimer, ces effets indésirablesde l’IOCCL. Des simulations numériques aux grandes échelles (LES) ont été réalisées en sebasant sur une configuration expérimentale deWang et al. (2012) relative au contrôle de l’IOCCLpar des micro-rampes, avec un nombre de Mach de M = 2.7 et un nombre de Reynolds deRe× = 3600. L’utilisation de ces dispositifs de contrôle se traduit par une réorganisation de lazone de recirculation en brisant l’homogénéité dans la direction transverse de l’écoulement, eten induisant un changement au niveau du mouvement du pied de choc réfléchi qui présenteune zone d’excursion fortement impactée par le sillage des micro-rampes. Des simulationscomplémentaires portant sur trois nouvelles configurations de micro-rampes possédant descaractéristiques géométriques différentes de celle du cas de référence ont permis de dresser unbilan de l’efficacité de ces dispositifs sur le contrôle de l’IOCCL en confrontant l’effet de mVGsde taille réduite à celui de mVGs de taille plus conventionnelle
Because it is ubiquitous in high Mach number internal and external flow of interest in aeronauticalapplications, shock wave/turbulent boundary layer interaction (SBLI) is characterised by alow-frequency unsteadiness which generates large wall-pressure fluctuations that can occur at theresonant frequency of the structures. This work is devoted to the study of passive flow controldevices such as microramp vortex generators (mVGs) to alleviate these detrimental effects of SBLI.Large-eddy simulations (LES) have been performed based on an experimental configurationby Wang et al. (2012) of a SBLI under the influence of microramps at a Mach number ofM = 2.7 and a Reynolds number of Re× = 3600. The use of microramps has been shown toenable a reorganisation of the recirculation zone by breaking the spanwise homogeneity of theinteraction, yielding to a change of the reflected shock foot back and forth motion along the span.Additional simulations on three new configurations allowed to assess the effectiveness of microrampsin controlling the SBLI by comparing reduced size mVGs with more conventional ones

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El, Alaoui-Faris Yacine. "Modélisation et contrôle optimal de micro-nageurs magnétiques". Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4094.

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Les micro-nageurs robotiques permettent d'effectuer des opérations à petite échelle telles que l'administration ciblée de médicaments et la chirurgie peu invasive. En raison de la difficulté de miniaturiser des sources d'énergie internes, les méthodes d'actionnement externes sont préférables aux sources intégrées, une stratégie populaire étant l'aimantation du nageur ou d'une de ses parties et son actionnement avec des champs magnétiques externes. L'étude qui suit se concentre sur les micro-nageurs magnétiques flexibles qui imitent les cellules flagellées commeles spermatozoïdes dans leur conception et leur mode de locomotion. Le but decette thèse est d'appliquer des outils numériques de modélisation et de contrôle optimal aux nageurs expérimentaux de l'Institut des Systèmes Intelligents et de Robotique (ISIR) afin d’améliorer leur contrôle et de fournir une méthode numérique pour la conception de commandes pour les micro-nageurs flexibles. La première étape de cette thèse a été le développement d'un modèle dynamique simplifié d'un nageur magnétique flexible en trois dimensions, basé sur une approximation des forces hydrodynamiques et sur la discrétisation de la courbure et de l'élasticité du flagelle. Une identification des paramètres hydrodynamiques et élastiques du modèle permet d'avoir un nageur simulé qui présente les mêmes caractéristiques de propulsion (notamment la réponse fréquentielle du nageur) que celles mesurées expérimentalement. La seconde étape a été d'utiliser le modèle développé pour la résolution numérique du problème de contrôle optimal consistant à de trouver le champ magnétique qui maximise la vitesse de propulsion du nageur sous des contraintes sur la commande reflétant les contraintes physiquement imposées au champ magnétique. La dernière étape a été l'implémentation des champ magnétiques calculés dans le dispositif expérimental de l'ISIR et l'étude de leur performances expérimentales ainsi que de la capacité du modèle à prédire la trajectoire du nageur
Robotic micro-swimmers are able to perform small-scale operations such astargeted drug delivery, and minimally invasive medical diagnosis and surgery.However, efficient actuation of these robots becomes more challenging as their size decreases. Hence, wireless actuation is preferable over built-in actuation sources, one of the most popular strategies is the magnetization of parts of the swimmer and its actuation with an external magnetic field. In this thesis, we focus on flexible magnetic micro-swimmers that are similar to spermatozoa in their design and flagellar propulsion. Our goal is to use numerical modeling and optimal control tools to improve the performance of existing swimmers made at the ISIR laboratory (Institut des Systèmes Intelligents et de Robotique) and to propose a numerical control design method for experimental flexible micro-swimmers.Firstly, a simplified 3D dynamic model of a flexible swimmer has been developed, based on the approximation of hydrodynamic forces and the discretization of the curvature and elasticity of the tail of the swimmer. By fitting the hydrodynamic and elastic parameters of our model accordingly, we are able to obtain propulsion characteristics (mainly the frequency response of the swimmer) close to those experimentally measured. Secondly, we numerically solve the optimal control problem of finding the actuating magnetic fields that maximize the propulsion speed of the experimental swimmer under constraints on the control that reflect the constraints physically imposed on the magnetic field. The optimal magnetic fields found via numerical optimization are then implemented in the ISIR experimental setup in order to benchmark the experimental performance of the computed controls and the ability of the model to predict the trajectories of the experimental swimmer

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Deganello, Juliana. "Avaliação da contribuição dos hormônios vegetais na interação Moniliophthora perniciosa x Solanum lycopersicum". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/64/64133/tde-20092013-095938/.

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A vassoura-de-bruxa consiste numa importante enfermidade do cacaueiro (Theobroma cacao), causada pelo basidiomiceto Moniliophthora perniciosa e caracterizada pelos sintomas de inchamento e indução de brotações laterais nos ramos infectados. O mecanismo de resistência do cacaueiro a M. perniciosa ainda é desconhecido e o longo ciclo de vida da espécie dificulta o seu estudo. Isolados do biótipo-S do patógeno infectam o tomateiro (Solanum lycopersicum), cuja cultivar miniatura \'Micro-Tom\' (MT) consiste num potencial modelo genético para o estudo da interação. A avaliação desse modelo foi iniciada com a caracterização sintomatológica de MT à inoculações com isolados de M. perniciosa do biótipo-S. Os sintomas avaliados nas plantas infectadas foram engrossamento do caule e desenvolvimento de \'vassouras laterais\'. Na caracterização histopatológica da interação MT e M. perniciosa por microscopia eletrônica de varredura foi observada a germinação preferencial de basidiósporos na base dos tricomas com pontos de penetração através de ferimentos e diretamente pela epiderme. Foi observado por microscopia óptica, aumento no volume celular de plantas infectadas e, a microscopia eletrônica de transmissão detectou a colonização da região intercelular pelo fungo com formação de matriz extracelular envolvendo a hifa. A contribuição dos hormônios vegetais na patogênese foi avaliada por meio de mutantes e plantas transgênicas no background \'Micro-Tom\' com alterações nas vias de biossíntese ou percepção hormonal. As classes hormonais e genótipos avaliados foram brassinosteróide (curl3), auxina (diagiotropica), etileno (epinastic e Never ripe), ácido abscísico (notabilis) giberelina (procera), ácido jasmônico (jasmonic acid insensitive 1e prosistemina), citocinina (CKX2) e ácido salicílico (NahG). Os genótipos que se mostraram mais susceptíveis a infecção por M. perniciosa avaliado por taxa de infecção de plantas, quando comparados ao MT foram epinastic, notabilis, procera e jasmonic acid insensitive 1, sendo que os restantes foram menos susceptíveis, sugerindo que possivelmente a redução da susceptibilidade à M. perniciosa relaciona-se ao aumento nos níveis de jasmonato (JA), em contraponto com o ácido salicílico (AS), que quando em níveis elevados parece aumentar o número de plantas sintomáticas. A infecção cruzada por isolados do biótipo-C foi caracterizada em MT, mutantes hormonais e transgênicos, contudo não foi possível observar sintomas em nenhum genótipo. A interação entre M. perniciosa do biótipo-S e -C e MT foi avaliada por expressão de genes envolvidos na resposta de defesa da planta por RT-qPCR. Após a inoculação com o biótipo-S, o maior número desses genes apresentou acúmulo de transcritos 48 h após a inoculação, seguido do momento a 120 h. Em contrapartida, nas inoculações com o biótipo-C, a indução dos genes deu-se no período de 48 h, porém a resposta atingiu os maiores níveis de expressão 72 h após a inoculação. Mutantes hormonais (jasmonic acid insensitive 1 e curl3) e plantas transgênicas (prosistemina e NahG) também foram avaliados para expressão de genes ligados a resposta de defesa das plantas por RT-qPCR. Os dois genótipos transgênicos que se mostraram menos susceptíveis, demonstraram a expressão de um inibidor de proteinase sinalizado pela via de JA, corroborando a hipótese que a redução no número de plantas com infecção por M. perniciosa esteja ligada a ativação da via do ácido jasmônico
Witches\' broom disease is a major disease of cacao (Theobroma cacao), caused by the basidiomycete Moniliophthora perniciosa, characterized by symptoms, such as tissue swelling and induction of lateral buds in infected branches. Cacao resistance mechanisms against M. perniciosa remain unknown, and the long lifecycle of such species impairs the study of the interaction. Moniliophthora perniciosa S-biotype- isolates infect tomato (Solanum lycopersicum), and the miniature cultivar \'Micro-Tom\' (MT) is a potential genetic model for the study of plant and pathogen interaction. Evaluation of this model started with the characterization of symptoms in MT plants inoculated with S-biotype isolates. Symptoms evaluated were stem swelling and the development of lateral broom. Through histological characterization of the interaction by scanning electron microscopy, it was possible to observe the preferential germination of basidiospores in the base of trichomes, with penetration points through wounds or directly through the epidermis. Increase in cellular volume in infected tissues was observed by light microscopy, and the colonization of the intercellular region by the fungus was detected through transmission electron microscopy, with the formation of an extracellular matrix involving the hypha. The contribution of plant hormones during pathogenesis was evaluated through the use of mutants and transgenic plants on the \'Micro-Tom\' background with alterations in hormonal biosynthetic pathways or perception/signaling. The hormonal classes and genotypes evaluated were for brassinosteroids (curl3), auxin (diageotropica), ethylene (epinastic and Never ripe), abiscisic acid (notabilis); gibberellin (procera); jasmonic acid (jasmonic acid insensitive 1e prosistemina); cytokinins (CKX2) and silicic acid (NahG). The genotypes epinastic, notabilis, procera e jasmonic acid insensitive 1 behaved as being more susceptible to M. perniciosa infection when compared to MT, while the remaining mutants were less susceptible, suggesting that the reduction in susceptibility to M. perniciosa might be related to the increase in jasmonate levels (JA), in the opposite to the levels of salicylate, which seems to increase together with the increase of symptomatic plants. Cross infection with biotype-C isolates was characterized in MT, hormonal mutants and transgenic plants, however typical symptoms of the disease were not observed in any of the genotypes inoculated. Genes involved in plant response and defense were evaluated for expression levels by RT-qPCR in the interaction between M. perniciosa S-and C-biotype with MT . After inoculation with S-biotype, the largest number of genes were up-regulated 48 h after inoculation, followed by a peak at the 120 h sampling. On the other hand, for C-biotype inoculation, gene induction started 48 h after inoculation, but the largest number of transcripts was detected after 72 hours. Hormonal mutants (jasmonic acid insensitive 1 and curl3) and transgenic plants (prosistemina and NahG) were also assessed for expression levels of genes related to plant response and defense. Both transgenic genotypes which behaved less susceptible to the disease showed up-regulation of a proteinase inhibitor typically signaled by JA pathway, corroborating the hypothesis that the reduction of the number of plants infected by M. perniciosa may be related to the jasmonic acid pathway

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Liu, Zhen. "Reconstruction and Control of Tip Position and Dynamic Sensing of Interaction Force for Micro-Cantilever to Enable High Speed and High Resolution Dynamic Atomic Force Microscopy". The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483629656167247.

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50

Wei, Linkai. "Development of a new steam explosion model for the MC3D software". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0097.

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Abstract (sommario):

L'explosion de vapeur est l'un des phénomènes les plus critiques et complexes qui peuvent se produire lors d'un accident grave dans une centrale nucléaire. Le code MC3D est reconnu comme une référence pour l'évaluation de ce phénomène. Ce phénomène explosif est analogue à une détonation. L'explosion est due à la fragmentation du combustible fondu, au passage de l'onde de choc et à la libération très rapide de l'énergie associée. Cependant, les mécanismes précis du processus de pressurisation sont très incertains et ont fait l'objet de travaux réalisés dans le cadre du programme RSNR-ICE (2014-2023), qui ont permis de mieux comprendre la phénoménologie générale et de valider le principe général de MC3D, basé sur un principe d'ébullition directe autour de la surface des fragments de corium via un mécanisme d'ébullition en film. Or, il apparaît que les processus de fragmentation semblent, dans certaines conditions, se réaliser sans une dispersion significative des fragments dans l'eau, ce qui est contraire à ce que présuppose le modèle MC3D actuel. L'objectif de la thèse est de proposer une modélisation améliorée de l'explosion pour MC3D, combinant le principe actuel d'ébullition directe et d'interaction combustible-refroidissement localisée dans un petit volume autour des gouttes de corium et des fragments. Après une bibliographie extensive du phénomène d'explosion de vapeur, une analyse détaillée du comportement du modèle MC3D actuel est effectuée, en utilisant un cas-test simple et idéal. Malgré la simplicité de l'ensemble de données, l'analyse peut être directement appliquée aux expériences à géométrie unidimensionnelle telles que KROTOS. Le rôle crucial du vide initial et du vide créé est mis en évidence ; il suggère également les premiers contours d'un nouveau modèle. Le logiciel Basilisk a ensuite été utilisé pour effectuer des simulations DNS afin d'obtenir des détails sur les transferts thermiques de fragmentation et d'association. Une analyse complète des régimes de fragmentation, des statistiques incluant le diamètre moyen de Sauter et la fonction de densité de probabilité de la masse et de la surface des fragments, du nombre de Nusselt transitoire et du coefficient de traînée a été menée. Dans le même temps, les résultats du même cas d'essai utilisant MC3D sont comparés à ceux de Basilisk, ce qui met en évidence la nécessité de modifier le modèle MC3D. Enfin, les grandes lignes d'un nouveau modèle proposé sont présentées et discutées. Celles qui ont pu être validées directement à partir des résultats du DNS ont été implémentées dans la version actuelle de MC3D. Il s'agit en particulier de l'introduction d'une Micro-Interaction de Non-Equilibre (NEMI), Les autres propositions concernant le comportement du vide pourront être implémentées dans la future version (V4) du code
The steam explosion is one of the most critical and complex phenomena that may occur during severe accident in a Nuclear Power Plant. The MC3D computer code is recognized as reference for the evaluation of this phenomenon. This explosive phenomenon is analogous to a detonation. The explosion is due to the fragmentation of the molten fuel, the passage of the shock wave and the very fast release of the associated energy. However, the precise mechanisms of the process of pressurization are very uncertain and have been the subject of works carried out under the program RSNR-ICE (2014-2023), which led to an increased understanding of general phenomenology and validated the general principle of MC3D, based on a principle of direct boiling around the surface of the corium fragments via a film boiling mechanism. However, it appears that the fragmentation processes seem, under certain conditions, to be achieved without a significant dispersion of the fragments in the water, which is contrary to what presupposes the current MC3D model. The aim of the thesis is to propose an improved modeling of the explosion for MC3D, combining the current principle of direct boiling and fuel-coolant interaction localized in a small volume around the corium drops and fragments. Following an extensive bibliography of the steam explosion phenomenon, a detailed analysis of the behavior of the current MC3D model is performed, using a simple and ideal test-case. Despite the simplicity of the data set, the analysis can be directly applied to experiments with one-dimensional geometry such as KROTOS. The crucial role of initial and created void is highlighted; It also suggests the first outlines of a new model. The Basilisk software was then used to perform DNS simulations to get details of fragmentation and association heat transfers. Comprehensive analysis about fragmentation regimes, statistics including Sauter Mean Diameter and Probability Density Function of fragment mass/area, the transient Nusselt number and drag coefficient were conducted. At the same time, results for the same test-case using MC3D are compared with that of Basilisk, highlighting the need of modification of MC3D model. Finally, the main lines of a proposed new model are presented and discussed. Those that could be directly validated from the DNS results were implemented in the current MC3D version. This concerns in particular the introduction of a Non-Equilibrium Micro-Interaction (NEMI), The other proposals concerning the behavior of the void may be implemented in the future version (V4) of the code

Tesi sul tema "Micro-interaction"

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