Дисертації з теми "Confinement model"
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Hill, Maxwell D. "Confinement tuning of a 0-D plasma dynamics model." Thesis, Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/55057.
Повний текст джерелаWood, Toby. "The solar tachocline : a self-consistent model of magnetic confinement." Thesis, University of Cambridge, 2011. https://www.repository.cam.ac.uk/handle/1810/230114.
Повний текст джерелаPapastergiou, Panagiotis. "A confinement model for concrete wrapped of pretensioned with frp." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527213.
Повний текст джерелаGersberg, Paul. "Confinement and driving effects on continuous and discrete model interfaces." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0084.
Повний текст джерелаThis thesis examines the properties of the interface between two phases in phase separated systems. We are interested in how finite size effects modify the statistical properties of these interfaces, in particular how the dependence of the free energy on the system size gives rise to long range critical Casimir forces close to thecritical point. Often the interfaces in phase separated systems are described by simplified or coarsegrained models whose only degrees of freedom are the interface height. We review how the statics and dynamics of these interface models can be derived from microscopic spin models and statistical field theories. We then examine finite size effects for continuous interface models such as the Edwards Wilkinson model and discrete models such as the Solid-On-Solid model and discuss their relevance to the critical Casimir effect. In the second part of the thesis we examine models of driven interfaces which have nonequilibrium steady states. We develop a model C type model of an interface which shows a nonequlibrium steady state even with constant driving. The resulting nonequlibrium steady state shows properties seen in experiments on sheared colloidal systems, notably the suppression of height fluctuations but an increase in the fluctuations’correlation length. Finally we propose a new model for one dimensional interfaces which is a modification of the solid on-solid model and containing an extra entropic term ,whose correspondance with physical systems is yet to be found
Mackura, Mark. "Nano-confinement Effects of Crystalline Walls on the Glass Transition of a Model Polymer." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1366815752.
Повний текст джерелаVu, Xuan Dung. "Vulnérabilité des dalles en béton sous impact : caractérisation, modélisation et validation." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENI028/document.
Повний текст джерелаConcrete is a material whose behavior is complex, especially in cases of extreme loads. The objective of this thesis is to carry out an experimental characterization of the behavior of concrete under impact-generated stresses (confined compression and dynamic traction) and to develop a robust numerical tool to reliably model this behavior. In the experimental part, we have studied concrete samples from the VTT center (Technical Research Center of Finland). At first, quasi-static triaxial compressions with the confinement varies from 0 MPa (unconfined compression test) to 600 MPa were realized. The stiffness of the concrete increases with confinement pressure because of the reduction of porosity. Therefore, the maximum shear strength of the concrete is increased. The presence of water plays an important role when the degree of saturation is high and the concrete is subjected to high confinement pressure. Beyond a certain level of confinement pressure, the maximum shear strength of concrete decreases with increasing water content. The effect of water also influences the volumic behavior of concrete. When all free pores are closed as a result of compaction, the low compressibility of the water prevents the deformation of the concrete, whereby the wet concrete is less deformed than the dry concrete for the same mean stress. The second part of the experimental program concerns dynamic tensile tests at different loading velocities, and different moisture conditions of concrete. The results show that the tensile strength of concrete C50 may increase up to 5 times compared to its static strength for a strain rate of about 100 s-1. In the numerical part, we are interested in improving an existing constitutive coupled model of concrete behavior called PRM (Pontiroli-Rouquand-Mazars) to predict the concrete behavior under impact. This model is based on a coupling between a damage model which is able to describe the degradation mechanisms and cracking of the concrete at weak confinement pressure and a plasticity model which allows to reproduce the concrete behavior under strong confinement pressure. The identification of the model was done using the results of experimental tests. The improvement of this model, especially the plasticity part, focuses on three main points : taking into account the effect of the deviatoric stress in the calculation of the mean stress; better accounting for the effect of water using poromechanical law instead of mixing law, improvement of the coupling variable between the damage model and the elastoplastic model with consideration of the Lode angle. These improvements were then validated by comparing numerical results and impact tests. The improved model is capable of reproducing the behavior of concrete under different loading paths and at different levels of confinement pressure while taking into account the degree of saturation of concrete
Mejia, Franco Maria Juliana. "Evaluation of Pond/Wetland/Vegetative Filter System to Treat Beef Manure Pile and Outdoor Confinement Area Runoff." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38554.
Повний текст джерелаSocié, Adrien. "Modélisation chimio-mécanique de la fissuration de matériaux cimentaires : vieillissement et tenue des enceintes de confinement des centrales nucléaires." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS102.
Повний текст джерелаThe French "Institut de Radioprotection et de Sûreté Nucléaire" (IRSN) conducts researches on the impact of internal swellings reactions on concrete, such as Sulfate Reactions. Such reactions are characterized by the precipitation of ettringite which induces swellings and cracks by differential strain. These cracks are preferential location for ions diffusion and further ettringite precipitations.The aim of the study is to model the degradation of a mature material by ettringite pressure at the aggregate scale.A chemo-mechanical model based on a coupling between reactive transport (species diffusion and chemical reactions) and mechanics in cracked porous medium is developed and is solved with a generic staggered approach.The initial microstructure and poro-mechanical and diffusion parameters are estimated by hydration computing and analytical homogenization.The coupled chemo-mechanical model is validated and then applied to Sulfate External and Internal Attack.The impact of the concrete composition and the chemical environments on the swelling kinetics and crack path is taken into account. Furthermore, our simulations highlight the influences of inclusions and cracks on the inhomogeneous spatial distribution of precipitation areas of ettringite and associated swelling stress
Wang, Jin. "Modeling of concrete dehydration and multhiphase transfer in nuclear containment concrete wall during loss of cooling accident." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30098/document.
Повний текст джерелаNuclear power plant now takes an important part in the world's electricity generation. In human history, there have already been two tragic accidents in Chernobyl and Fukushima causing severe radioactive matter leakage. To pre- vent this kind of accident from happening again, concrete structure plays an important role as material of containment building, which is the last barrier to isolate the radioactive matter from the environment. Hence, the transfer properties of concrete under severe circumstances, especially high tempera- ture, are important for this usage. This PhD thesis aims to investigate the behavior of the concrete under high temperature up to 200°C. In the first part, a dehydration model was proposed. The model consists of different dehydration sub-models for main hydrates in the cement paste. In the second part, the dehydration model was implemented in a thermo-hygral model. The thermo- hygral model was then used to simulate a mock-up for which experimental results are available in the literature, without considering the mechanical behaviors. At last, parametric studies were performed to investigate the influ- ence of some parameters, and the model was then applied to structures under different heating rates, and structures with different thicknesses to compare the temperature and gas pressure profiles across a wall
Turgut, Can. "Prise en compte de la liaison acier béton dans le comportement d’éléments de structure en béton armé." Thesis, Paris 10, 2018. http://www.theses.fr/2018PA100170/document.
Повний текст джерелаIn numerical applications of reinforced concrete structures, the steel-concrete interface behavior has a vital importance when the cracking properties are investigated. A finite element approach for the steel-concrete interface to be used in large-scale simulations was proposed by (Torre-Casanova, 2013) and (Mang, 2016). It enables to calculate the slip between the steel and concrete in the tangential direction of the interface element representation. The aim is here to improve the initial bond-slip model to be more efficient and more representative. The document is divided into three parts: 1) The existing bond-slip model is evaluated. The bond-slip model is then improved by considering transversal and irreversible bond behaviors under alternative loads. The new bond-slip model is validated with several numerical applications. 2) Confinement effect is implemented in the bond-slip model to capture the effect of external lateral pressure. According to the performed numerical applications, it is demonstrated how the active confinement can play a role, through the steel-concrete bond, during monotonic and cyclic loading cases. 3) Dowel action is finally investigated with the new bond-slip model. Two different experimental campaigns (Push-off tests and four-point bending tests) are reproduced with different reinforcement (1D truss and beam) and interface (new bonds-slip and perfect bond) models. The results show that the proposed simulation strategy including the bond slip model enables to reproduce experimental results by predicting global (force-displacement relation) and local behaviors (crack properties) of the reinforced concrete structures under shear loading better than the perfect bond assumption which is commonly used in the industrial applications
Moharrami, Gargari Mohammadreza. "Development of Novel Computational Simulation Tools to Capture the Hysteretic Response and Failure of Reinforced Concrete Structures under Seismic Loads." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/71864.
Повний текст джерелаPh. D.
Arlt, Jan. "Experiments on Bose-Einstein condensation." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326008.
Повний текст джерелаTronko, Natalia. "Hamiltonian Perturbation Methods for Magnetically Confined Fusion Plasmas." Thesis, Aix-Marseille 2, 2010. http://www.theses.fr/2010AIX22088/document.
Повний текст джерелаThis thesis deals with dynamicla investigation of magnetically confined fusion plasmas by using Lagrangian and Hamilton formalisms. It consists of three parts. The first part is devoted to the investigation of barrier formation for the EXB drift model by means of the Hamiltonian control method. The strong magnetic field approach is relevant for magnetically confined fusion plasmas ; this is why at the first approximation one can consider the dynamics of particles driven by constant and uniform magnetic field. In this case only the electrostatic turbulence is taken into account. During this study the expressions for the control term (quadratic in perturbation amplitude) additive to the electrostatic potential, has been obtained. The effeciency of such a control for stopping turbulent diffusion has been shown analytically abd numerically. The second and the third parts of this thesis are devoted to study of self consistent phenomena in magnetized plasmas through the Maxwell-Vlasov model. In particular, the second part of this thesis treats the problem of the monumentum transport by derivation of its conservation law. the Euler-Poincare variational principle (with constrained variations) as well as Noether's theorem is apllied here. this derivation is realized in two cases : first, in electromagnetic turbulence case for the full Maxwell-Vlasov system, and then in electrostatic turbulence case for the gyrokinetic Maxwell-Vlasov system. Then the intrinsic mechanisms reponsible for the intrinsic plama rotation, that can give an important in plasma stabilization, are identified. The last part of this thesis deals with dynamicla reduction for the Maxwell-Vlaslov model. More particularly; the intrisic formulation for the guiding center model is derived. Here the term 'intrinsis" means that no fixed frame was used during its construction. Due to that not any problem related to the gyrogauge dependence of dynamics appears. The study of orbits of trapped particles is considered as one of the possible for illustration of the first step of such a dynamical reduction
Zohrevand, Pedram. "Novel Hybrid Columns Made of Ultra-High Performance Concrete and Fiber Reinforced Polymers." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/627.
Повний текст джерелаDowning, Charles Andrew. "Quantum confinement in low-dimensional Dirac materials." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/17215.
Повний текст джерелаPetrolli, Vanni. "Confinement induced transition between wave-like cellular migration modes." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAY056.
Повний текст джерелаThe ability of organisms to spontaneously generate order relies on the intricate interplay of mechanical and bio-chemical signals. If the general consensus is that chemical signaling governs the behavior of cells, an increasing amount of evidence points towards the impact of mechanical factors into differentiation, proliferation, motility and cancer progression. In this context, several studies recently highlighted the existence of long-range mechanical excitations (i.e. waves) at the supra-cellular level.Here, we investigate the origins of those velocity waves in tissues and their correlation with the presence of boundaries. Practically, we confine epithelial cell mono-layers to quasi-one dimensional geometries, to force the almost ubiquitous establishment of tissue-level waves. By tuning the length of the tissues, we uncover the existence of a phase transition between global and multi-nodal oscillations, and prove that in the latter regime, wavelength and period are independent of the confinement length. Together, these results demonstrate the intrinsic origin of tissue oscillations, which could provide cells with a mechanism to accurately measure distances at the supra-cellular level and ultimately lead to spatial patterning. Numerical simulations based on a Self-propelled Voronoi model reproduce the phase transition we measured experimentally and help in guiding our preliminary investigations on the origin of these wave-like phenomena, and their potential role for the spontaneous appearance of hair follicles in mouse skin explants
Mukherjee, Bikramjit. "Interfacial debonding from a sandwiched elastomer layer." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/71464.
Повний текст джерелаPh. D.
Smith, Arlynn W. "Light confinement and hydrodynamic modeling of semiconductor structures by volumetric methods." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/13407.
Повний текст джерелаRiederer, Kevin Allen. "Assessment of confinement models for reinforced concrete columns subjected to seismic loading." Thesis, University of British Columbia, 2006. http://hdl.handle.net/2429/31503.
Повний текст джерелаApplied Science, Faculty of
Civil Engineering, Department of
Graduate
Sayer, Min-hee Shin. "Evolution of radial force balance and radial transport over L-H transition." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45911.
Повний текст джерелаAnalytis, James. "Confinement and coherence : finite-sized models and disorder experiments on an organic superconductor." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427904.
Повний текст джерелаMazzolo, Alain. "Structure du vide dans le modele dielectrique de couleur : confinement et symetrie chirale." Paris 11, 1992. http://www.theses.fr/1992PA112208.
Повний текст джерелаVarillon, Grégoire. "Non-modal hydrodynamic stability analysis of ablation flows relative to inertial confinement fusion." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX106.
Повний текст джерелаAblation waves form when a dense medium is suddenly exposed to a strong irradiation flux. A forerunning shock front propagates inside the dense medium, followed by an ablation front which corresponds to the superposition of the foot of a heat front and the leading edge of a rarefaction wave. Ablation waves are highly sensitive to hydrodynamic instabilities due to their strong stratification and inherent accelaration.Ablation waves arise during the implosion of inertial confinement fusion (ICF) targets, for which they are critical regarding the compression of a sphericalfusion target. Achieving ICF ignition requires a sufficiently symmetrical implosion, which is possible if ablation front instabilities are controlled. However, the identification of the most dangerous initial defect regarding ablation front stability is difficult due to the multiplicity of perturbation sources.To address this issue, we carried out the first non-modal linear stability analysis of a radiation driven ablation wave. We make use of a self-similar flowmodel that renders the compressibility, unsteadiness and nonlinear heat conduction proper to ablation flows (Abéguilé et al., 2006; Clarisse et al., 2018). Initial optimal perturbations are identified for various terminal times and wavelengths and characterized according to their nature (acoustic, entropic, vorticity or boundary deformation). Two distinct optimal growth mechanisms are identified. They notably differ from the ablative Richtmyer–Meshkov instability. Initial optimal perturbations are obtained by means of direct–adjoint iterations. The adjoint problem is derived from the Lagrange multipliers technique. Particular attention is drawn to constraints on boundary conditions and free surface evolution equations while building the Lagrange functional. This work paves the way to a systematic identification of the most dangerous initial defects in the ablator of ICF targets regarding the implosion process
Frey, Marc. "Évolution quasi-linéaire d'un mode de déchirement : rôle de l'inertie, tendance à la saturation, diffusion thermique à travers l'îlot magnétique." Paris 11, 1985. http://www.theses.fr/1985PA112080.
Повний текст джерелаIn this thesis, the quasi-linear growth of resistive magnetohy-drodynamic instabilities (Tearing modes) in confined plasmas is investigated. The Tearing mode leads to the formation of magnetic islands. We study the role of inertia in the growth of the island, the possibility of non-linear saturation, and the effects of heat flow through the magnetic island
Rassem, Nadège. "Etude du guidage et du confinement de la lumière dans les guides optiques nanostructurés : application au filtrage spectral ultra-sélectif." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0015.
Повний текст джерелаA CRIGF (Cavity Resonator Integrated Grating Filter) is a nanophotonic spectral filter with a narrow bandwidth (less than a nanometer) using a relatively focused beam. This structure, introduced recently (2010), is composed of a guided mode resonance grating filter (or resonant grating, or coupler grating) inserted between two Bragg gratings. Guided mode resonance gratings are known to exhibit very narrow peaks in their reflection spectrum (or transmission), due to the excitation of one guided mode of the structure via one diffraction order. This resonance phenomenon corresponds to an anomaly of Wood. But their major limitation remains their very low angular tolerance, and the CRIGF allows to overpass this problem.In literature, the numerical modeling of CRIGF was done only by FDTD with an important calculations time. We have used RCWA to model numerically the CRIGF by bringing a possibility of research of the eigen-modes. We have mainly shown thanks to calculations the extraordinary angular behavior of the CRIGF is very different from that of infinite gratings. We have proved thanks to the coupled modes theory extended to four modes that this large angular tolerance is due to an additional coupling that did not occur in infinite gratings.With an approach based on the Fabry-Perot cavity, we confirmed that the CRIGF behaves as a lossy Fabry-Perot cavity, which allowed us to define simple design rules such as the control of the spectral width and tuning the centering wavelength
Zabiego, Maxime. "Stabilité des modes magnétiques dans les tokamaks." Aix-Marseille 1, 1994. http://www.theses.fr/1994AIX11029.
Повний текст джерелаLafleur, Gaël. "Nouvelles architectures de composants photoniques par l'ingénierie du confinement électrique et optique." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30263/document.
Повний текст джерелаOptical and electrical confinement using Al(Ga)As layer oxidation is a key milestone in the fabrication of active and passive GaAs-based photonic components. To optimize those devices, through the control of the optical and electrical confinements, a better modelling of oxidation process and a better understanding of optical properties of aluminum oxide (AlOx) is required. One part of this work is focusing on a throughout experimental study of AlGaAs oxidation kinetics, where I studied different important parameters such as wafer temperature, gallium composition, atmospheric pressure and mesa geometry. Then, I developed a new predictive model taking into account the process anisotropy, thus allowing a better temporal and spatial of AlAs oxidation front evolution. Finally, I could exploit this technological process to realize whispering gallery mode microdisks as well as slot optical waveguides, and I have characterized this latter photonic devices
Olofsson, K. Erik J. "Nonaxisymmetric experimental modal analysis and control of resistive wall MHD in RFPs : System identification and feedback control for the reversed-field pinch." Doctoral thesis, KTH, Fusionsplasmafysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-94096.
Повний текст джерелаQC 20120508
Nasr, Sabine. "Fluid and kinetic descriptions of the mutual interaction between tearing modes and thermal and energetic particles in tokamak plasmas." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0544/document.
Повний текст джерелаThe stability of collisionless tearing modes is analyzed in the presence of an inhomogeneous magnetic field in fluid and gyrokinetic theories. It is shown by means of a fluid model that small scale modes, characterized by a negative stability parameter ($\Delta^\prime<0), can be driven unstable due to a combination of the magnetic field and electron temperature gradients. The destabilization mechanism is identified as of the interchange type, similar to that for toroidal ETG modes. The resonant interaction between the mode and different classes of particles is studied in gyrokinetic theory. It is found that curvature and magnetic field inhomogeneity effectively change the mode stability through trapped particles. This is verified numerically with a gyrokinetic code (GKW) where the interchange-like destabilization is confirmed. Furthermore, the impact of a population of energetic particles is investigated. Linearly, using a gyrokinetic model, the particular case of energetic particle distribution presenting anisotropy in the temperature is taken into account. Non-linearly, the impact of the time evolution of the energetic particle density on the growth of magnetic islands is examined by means of a fluid model
Brooks-Bartlett, M. E. "Numerical investigations of classical spin models : the impact of lattice geometry, confinement and long-range interactions." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1471485/.
Повний текст джерелаMaloney, Soren E. "Acoustics and manufacture of Caribbean steelpans." Thesis, University of Cambridge, 2011. https://www.repository.cam.ac.uk/handle/1810/238665.
Повний текст джерелаDudok, de Wit Thierry Dudok de Wit Thierry Dudok de Wit Thierry Dudok de Wit Thierry. "La décomposition en modes propres : une approche nouvelle pour caractériser le confinement du plasma dans un tokamak /." [S.l.] : [s.n.], 1993. http://library.epfl.ch/theses/?nr=1050.
Повний текст джерелаSALLES, FREDERIC. "Surete de fonctionnement des logiciels executifs a base de micronoyau : analyse des modes de defaillance et confinement des erreurs." Toulouse 3, 1999. http://www.theses.fr/1999TOU30039.
Повний текст джерелаSantos, Fernanda de Oliveira. "Modelo constitutivo incremental explícito para o concreto confinado baseado na teoria da plasticidade e dano." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-10072018-114442/.
Повний текст джерелаConfinement of concrete columns through steel or composites jackets has an important function in the preservation, recovery and strengthening of structures, because it provides increased strength and ductility of these structural elements. However, most of the existing models have limitations in the prediction of the behavior of confined concrete, mainly because they are dependent on the type of confinement. This work presents a model for the description of the stress-strain behavior of the concrete submitted to any type of uniform confinement, active or passive, and confined with different confinement materials, steel or composites. The constitutive model associates plasticity and damage in order to predict with accuracy the strength, ultimate strain and reduction of elastic stiffness of the confined concrete. The model is developed by an explicit incremental implementation process allowing, therefore, its development in any type of spreadsheet. Finally, the model was validated through a representative set of experiments found in the literature.
Bazin, Maela. "Contrôle de l’émission spontanée de boîtes quantiques semiconductrices insérées dans des micro-structures à confinement optique originales." Grenoble, 2010. https://theses.hal.science/tel-00592414v1.
Повний текст джерелаThis study deals with the control of spontaneous emission, InAs quantum dot emitters, confined via original microstructures: GaAs photonic wires and micropillars with GaAs/AlAs Bragg mirrors. We present a higly efficient single-photon source based on a photonic wire. Correlation mesurements performed on a single quantum dot inserted in a photonic wire led to a pure and high broadband single-photon generation. The optimization of this geometry including an original mirror at the wire bottom and a taper at its top demonstrated a record efficiency of 70%. In addition, the systematic lifetime study of single quantum dots underlined the ability to observe a high inhibition of spontaneous emission in the leaky modes with this geometry. In the last part of this PhD Thesis, we show the laser effect in whispering gallery mode micropillars. Those modes have an almost stable behaviour in terms of wavelengh and a spectral narrowing maintained up to power corresponding to 7 times the laser threshold. This result confirms a better thermal stability of micropillars compared to microdisks, a geometry usually used to observe the whispering gallery modes
Furlan, Alexandre Penteado. "Computational study of the effects of the confinement and the interacting solutes on the properties of the water-like models." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/156634.
Повний текст джерелаAlthough the familiarity and simplicity, the water show a set of thermodynamic, dynamics and structural properties which are still subject to intense research. The increase of density as the temperature, of diffusion as the density, or even of ordering with the temperature are examples of some of its unusual behavior. In order to better understand these properties numerous approaches have been used, such as the use of confinement geometries, simplified models, or ever mixtures. Among the confinement geometries used, are those, nanopores, parallel plates and porous media. The porous media are formed by fixed obstacles that impose the additional excluded volume effects to the system. In the case of mixtures, when they occur between liquids able to form hydrogen-bonds, the unusual behavior of water give rise to a set even higher anomalous properties. The water-methanol mixture, for example, has a set of excess properties unable to be described by usual theories. Some examples are the maximum in the specific heat and minimum in excess volume and enthalpy. In this Ph.D. project, we study by numerical simulations, the confinement of water by porous media(or under quenched disorder) and the mixture of water with interacting solutes. The first study is performed using a 2D lattice model which is widely known in the literature. In a second stage, we study the influence of interacting solutes on the properties of lattice and continuous models. For the lattice model, we develop a solute model and a technique to simulate mixtures of lattice models at constant pressure. Using this technique, we study the excess properties of the mixture. For the continuous model we study the influence of a dimeric solute on the TMD of a water-like model and posteriorly we study the excess properties of this type of mixture.
Du, Fengshuang. "Investigation of Nanopore Confinement Effects on Convective and Diffusive Multicomponent Multiphase Fluid Transport in Shale using In-House Simulation Models." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/100103.
Повний текст джерелаDoctor of Philosophy
Shale reservoir is one type of unconventional reservoir and it has extremely small pore size, low porosity, and ultra-low permeability. In tight shale reservoirs, the pore size is in nanometer scale and the oil-gas capillary pressure reaches hundreds of psi. In addition, the critical properties (such as critical pressure and critical temperature) of hydrocarbon components will be altered in those nano-sized pores. In this research, two in-house reservoir simulation models, i.e., a compositionally extended black-oil model and a fully composition model are developed to examine the nano-pore confinement effects on convective and diffusive multicomponent multiphase fluid transport. The large nano-confinement effects (large gas-oil capillary pressure and critical property shifts) on oil or gas production behaviors will be investigated. Meanwhile, the nano-confinement effects and rock intrinsic properties (porosity and tortuosity factor) on predicting effective diffusion coefficient are also studied.
Merghem, Kamel. "Etude de lasers à verrouillage de modes à semiconducteur pour les réseaux de télécommunications à très haut débit." Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10092/document.
Повний текст джерелаThis PhD thesis deals with the study of passive quantum-dash-based mode locked laser in different configurations: 2-section device (one gain section and one saturable absorber section) and self pulsating laser using a single section device.We have assessed in particular phase noise and timing jitter in optical pulses. The latter is very important for low jitter applications as ail optical clock recovery and millimeter wave generation. Stabilization technique based on optical feedback has been applied to reduce the timing jitter. Moreover, we present passive mode locked operation of a self-pulsating quantum dash Fabry-Perot laser diode at arepetition rate over 300 GHz
Martinet, Quentin. "Étude des effets environnementaux sur les modes acoustiques confinés de nanoparticules par diffusion inélastique de la lumière." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1152/document.
Повний текст джерелаOver the past twenty years, inelastic light scattering by vibrational eigenmodes of nanoparticles, called Lamb modes, has proven to be an effective method for characterizing the size and mechanical properties of nano-objects. The resonant frequency of a nano-sphere, in the gigahertz range, is given, as a first approximation, by the ratio of the acoustic velocity of the bulk material and the size of confinement. The refinements of the theoretical model allow to obtain, from these eigenmodes, information on the shape and local environment of nano-objects.The objective of this thesis is to probe the domain of validity of the Lamb model, to analyze the different impacts of the environment on eigenmodes and to develop a new strategy to measure them. Several aspects of interaction with the external medium can be considered depending on the system studied. On the one hand, the delocalization of the acoustic wave in the case of core shell systems is ruled by the acoustic impedance of the core and the shell and leads to a mechanical coupling. On the other hand, the inertial mass effect induced by the presence of organic ligands on the surface of the particle modifies the resonant frequency. The validity of both approaches is discussed according to the configuration and these models are applied to real cases, such as semiconductor core shell nanoparticles and nanoplatelets, or gold colloidal clusters. The inertial mass effect is significant for small objects and it is shown the feasibility to realize ultra-sensitive nano-balance capable of probing the local environment of nano-objects. Furthermore, in the case of gold clusters, this approach makes it possible to discuss the limit of the Lamb model, based on continuum mechanics, to interpret vibrations involving only six atoms. Thanks to low frequency Raman spectroscopy, it appears that the experimental results are in good agreement with both the continuum mechanics approach, by considering the inertial mass effect, and also with density functional theory (DFT) calculations. Finally, the experimental development of an optical set-up capable of measuring low frequency Raman modes on a single nanoparticle in a liquid medium is presented. This technic requires to localize a nanoparticle in a liquid medium with plasmonic tweezers and to enhance the low frequency Raman signal by stimulating vibrational modes with electrostriction. The perspectives are to apply this method to the dynamical study of a single object such as viruses or proteins
Bazin, Maela. "Contrôle de l'émission spontanée de boîtes quantiques semiconductrices insérées dans des micro-structures à confinement optique originales." Phd thesis, Université de Grenoble, 2010. http://tel.archives-ouvertes.fr/tel-00592414.
Повний текст джерелаRegan, Cyril. "Modéles réduits pour le transport de particules rapides dans le cadre de la fusion par confinement inertiel." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14138/document.
Повний текст джерелаThe energy transport in the Fast Ignition scheme within the framework of Inertial Confinement Fusion (ICF) is done by means of energetic charged particles, relativistic electrons or fast ions. The particle transport and energy deposition process is rather complicated and its detailed description requires large scale kinetic multidimensional calculations. These codes are CPU time consuming and cannot be easily implemented in radiation hydrodynamic codes that describe the fuel assembly, resulting energy deposition and the combustion. Reduced methods are needed that account for the main features of the kinetic transport process and are sufficiently fast and efficient to be introduced directly in an hydrodynamic module. We have developed two reduced models of charged particles transport, suitable for integration in hydro-codes. The first model, called Trumpet, is a two-dimensional extension of a simplified 1D model for the average scattering angle. The second model called M1 is a simplification of the Fokker Planck equation, based one the angular closure respecting the minimum entropy principle. These two models have been integrated in the CELIA hydrodynamic code (CHIC). After considering the advantages and limitations of these models, we used them to calculate the ion energy deposition in a compressed target. We have modelled the protonic radiography of a cylindrical laser-driven impulsion, and analyse a new fast ignition scheme with fast deuterium tritium and carbon ions accelerated by laser
Mapesa, Emmanuel Urandu. "Molecular dynamics of nanometric layers of glass formers in interaction with solid substrates." Doctoral thesis, Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-155709.
Повний текст джерелаAlchaar, Mohanad. "Confinement et transfert de charges dans les systèmes îlots Au/AlN et îlots graphène/SiC." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30287.
Повний текст джерелаThe study of confinement and charge transfer within metallic nano-objects deposited on an insulating substrate is a major challenge from a scientific and technological viewpoint. Such a system could serve as a reservoir of electrons to study the transfer in a molecular wire. During this thesis, the technique used is non-contact atomic force microscopy (NC-AFM) connected under ultra-high vacuum (UHV) and coupled to the Kelvin probe (KPFM), allowing the measurement and transfer of electric charges. The insulating substrate used in this thesis is aluminum nitride AlN (0001) prepared by molecular beam epitaxy (MBE). A first growth study of four metals (Mg, In, Ag and Au) by MBE has highlighted the fundamental importance of the AIN (0001) surface on the growth modes. This study showed that only the gold deposited on the AlN (0001) (2×2)-Nad reconstructed surface gave rise to two-dimensional (2D) growth with the formation of nano-islands a thick monolayer. The analysis of NC-AFM images at atomic resolution obtained at 5K, coupled with DFT calculations, shows that the stabilization of the gold nano-islands are due to the formation of a chemical bond between the gold and the AlN surface (0001). These 2D gold nano-islands on AlN (0001) could have been positively or negatively charged during NC-AFM experiments: the characteristic signature of the charge is observed during DELTA f(V) spectroscopies, with the offset of the CPD potential linked to the injected load. Time tracking of the Kelvin potential on a charged island makes it possible to measure a decay time of several days, a sign that the AlN substrate is a very good insulator. In order to understand the charge mechanism of these metallic islands by NC-AFM, these charge experiments were reproduced on 20 nm thick gold nanocrystals deposited on an insulating layer of thermal SiO2. An analytical model coupled with numerical simulations made it possible to show that the charge injection takes place by field emission between the tip and the metallic island. These calculations show that it is possible to control with ready electron the amount of charge injected into a metallic island. The last part of this thesis is devoted to the measurement by NC-AFM / KPFM of the height of three types of graphene (ZLG, EMLG and QFMLG) and two islands of graphene. The study is carried out on two types of samples: nano-islands of graphene grown by CVD on a 6H-SiC(0001) substrate and graphene layers obtained by high temperature sublimation of 6H-SiC(0001), with a half monolayer coverage rate. Analysis of the NC-AFM images made it possible to determine the height of the buffer layer (ZLG) equal to 2.62 Å, of the epitaxial layer graphene on the buffer layer (EMLG), equal to 4.09 Å, as well as a bilayer graphene equal to 6.86 Å. The height of an island of graphene on SiC is 6.28 ± 0.52 Å and an island of graphene on ZLG is characterized by a height of 3.69 ± 0.11 Å
Storelli, Alexandre. "Étude du transport turbulent dans les plasmas du tokamak Tore Supra : observation des écoulements perpendiculaires stationnaires et du mode acoustique géodésique." Palaiseau, Ecole polytechnique, 2015. https://theses.hal.science/tel-01167913v2/document.
Повний текст джерелаTokamaks are toroidal machines designed to magnetically confine plasma and to host reactions of nuclear fusion. Their performance is limited by turbulent transport, which precise mechanisms are not fully elucidated. Turbulent fluctuations cause the onset of macroscopic mean flows, in the direction perpendicular to both magnetic field and small radius, called zonal flows. Their shear is known to decrease both fluctuation level and transport. Diagnostics of Doppler backscattering have been installed on Tore Supra (CEA Cadarache). They could measure the perpendicular velocity of turbulent fluctuations in different zones of the plasma. First, it is shown that, on average, fluctuations flow twice as fast at the low field side of the machine than at its top. The difference, significantly higher than predicted by common models, is put in perspective with the properties of magnetic equilibrium and the behaviour of fluctuations. Then, variations of the velocity, due to the zonal flow branch called geodesic acoustic mode (GAM), are examined in a series of experiments where collisionality is varied. Those observations have been quantitatively compared with a gyrokinetic simulation with the code GYSELA, using the equilibrium profiles from the experiments. GAM frequency in experiments is lower than predicted, especially at low collisionalities. In addition, the instationarity of GAM has been characterized with the Hilbert-Huang transform. Burts of GAM oscillations have similar statistics between experiments and simulation and their duration could be related with the nonlinear interaction between the GAM and turbulence and with the continuum damping which is observed in the simulation
Gacemi, Djamal Eddine. "Étude expérimentale et simulation des modes électromagnétiques se propageant sur des guides d’ondes métalliques de petites dimensions aux fréquences THz." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112413.
Повний текст джерелаFocusing optical energy into a small spot diameter much smaller than the diffraction limit has long been a very interesting topic in photonics. In Terahertz (with a wavelength of about 300 microns) this challenge is particularly important to meet the growing interest in high-resolution imaging and spectroscopy of materials whose size is smaller than the wavelength in free space. In my thesis, I studied the confinement of surface waves at THz frequencies on metal structures with sub-wavelength dimensions . I experimentally measured the confinement of the electric field and calculated the dispersion relation of the surface mode on a metal structure deposited on a low permittivity dielectric substrate. These measurements are obtained using a guided-wave time domain spectroscopy set-up, developed during my PhD. The measurement is made by a near-field freely positionable electro-optical probe. These experimental results are supplemented by numerical simulations obtained by finite element analysis software Comsol Multiphysics. The experimental results show a confinement of λ/20 of the EM surface mode on a sub-wavelength dimension rectangular metal wire
Leduc, Christian. "Modélisation de la condensation en film sur les parois d'une enceinte de réacteurs." Université Joseph Fourier (Grenoble ; 1971-2015), 1995. http://www.theses.fr/1995GRE10157.
Повний текст джерелаSallander, Eva. "Magnetohydrodynamic spectroscopy of magnetically confined plasmas." Doctoral thesis, Stockholm : Tekniska högsk, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3139.
Повний текст джерелаShrestha, Pooja. "Mechanism of substrate protein remodeling by molecular chaperones." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1378113185.
Повний текст джерелаIvan, Michaela. "Résonateurs à haute fréquence à ondes de volume en réalisatin MEMS sur tranche silicium." Phd thesis, Université de Franche-Comté, 2012. http://tel.archives-ouvertes.fr/tel-00803165.
Повний текст джерелаBrugnara, Andrea. "Contrôle cavitaire de la réactivité redox d'un ion métallique (Cu) dans un environnement biomimétique." Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05P625/document.
Повний текст джерелаThe X6TMPA molecule is composed by a tris(2-pyridylmethyl)amine (TMPA) cap covalently linked to the small rim of the calix[6]arene. This compound can coordinate and stabilize a Cu(I)/Cu(II) ion in a mononuclear environment. These compounds possess unique properties in host-guest and redox chemistry.This PhD thesis work describes some synthetic strategies employed in order to modify the scaffold of the macrocycle, either at the large or the small rim. Moreover, the studies conducted in order to evaluate the impact of each structural modification on the reactivity of the resulting system are detailed. Chapter 2 describes the “large rim tri-functionalization” strategy. It has been employed to introduce three hydrophilic moieties on the calix[6]arene unit. These groups enable the water-solubilization of the molecule, as well as the Cu(I)/Cu(II) monometallic complexes. For these systems, host-guest chemistry in aqueous media has been explored: a remarkable property is the high affinity of the cupric complex for fluoride anion. Chapter 3 describes the “large rim hexa-functionalization” strategy. The obtained compounds have been employed for novel applications, as surface functionalization or “monoclick” reaction. Chapter 4 describes the “small rim tri-functionalization” strategy. The obtained compounds are reactive in solution. A phenol-containing macrocycle, that gives a stable radical species at room temperature, and a quinone-containing macrocycle, in which the calix[6]arene moiety is a redox-active unit, are presented. Moreover, the reactivity of the monometallic complexes (Zinc, Copper) has been explored and discussed