Tesi sul tema "Caractérisation thermique et thermocinétique"
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Hany, Cindy. "Développement de méthodes thermiques pour la caractérisation de réactions chimiques en microfluidique". Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13936/document.
This work deals with the development of new measurement methods in order to characterize high exothermic chemical reactions in safe conditions. Thus, we combine thermal analysis with microfluidic technology. The use of microfluidics allows to manipulate a very small amount of product safely. First, we have developed a microcalorimeter to measure the global heat flux produced in co-flow or droplet-flow configurations. Several parameters can be determined: reaction and mixing enthalpy, concentrations by calorimetric titration and kinetics. The second method uses an InfraRed camera to measure the temperature field of the isoperibolic millireactor. Then, the local evolution of the reaction is estimated by thermal processing. From such inverse methods, the thermokinetic parameters can be determined
Coumes, Isabelle. "Caractérisation thermocinétique d'une installation d'analyse thermique différentielle automatisée". Grenoble INPG, 1986. http://www.theses.fr/1986INPG0095.
Djanna, Koffi Francis Lénine. "Convection naturelle turbulente en cavité différentiellement chauffée à grands nombres de Rayleigh : caractérisation expérimentale des écoulements et des transferts thermiques, étude numérique du couplage convection-rayonnement". Phd thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2011. http://tel.archives-ouvertes.fr/tel-00595352.
Flity, Hassan. "Modélisation de la dégradation et combustion du bois de construction". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0250.
The use of wood in construction offers numerous advantages, but also poses fire safety risks. Several studies available in the literature, whether experimental or numerical, have investigated the fire behavior of wood. However, the diverse and varied results do not allow the identification of the intrinsic behavior of wood, and regulatory frameworks have to rely on numerous simplifying assumptions. The objective of this thesis is to study the thermal degradation of wood at the cone calorimeter scale. The uniqueness of the study lies in the adoption of an increasingly complex approach, the use of meticulous metrology, and the most comprehensive characterization of the properties of the wood samples under investigation. Degradation involves numerous interacting processes such as drying, pyrolysis, and combustion with or without flames, resulting in heat and mass transfer. Given the complexity of studying all these phenomena simultaneously, the strategy adopted was to separate the different phenomena as much as possible through models and specific experiments. In order to overcome the problem of drying and hydric transfer, all the work was carried out on dry wood. First, specific characterization methods were used to determine the thermal properties of wood and charcoal. These experiments helped to establish behavioral laws for some of these properties, facilitating their integration into a model. Subsequently, an experimental campaign was conducted at the material scale of wood using techniques such as thermogravimetric analysis and differential scanning calorimetry under an inert atmosphere. At this scale, wood is thermally thin, which allowed the development of a kinetic model capable of predicting mass loss, mass loss rate, and heat absorbed or generated by wood during pyrolysis as a function of temperature. Next, an experimental campaign was carried out on wood samples at the scale of the cone calorimeter in an inert atmosphere to validate the 3D pyrolysis model developed to predict wood pyrolysis in the absence of combustion, driven primarily by heat transfer within the material. Finally, tests in an air environment were conducted for a comprehensive modeling of dry wood combustion, which requires a precise characterization of char combustion, the associated heat generated, and the heat flux supplied by the flame
Duquesne, Loys. "Caractérisation thermique de structures composites SiCf/SiC tubulaires pour applications nucléaires". Thesis, Paris, ENSAM, 2015. http://www.theses.fr/2015ENAM0052/document.
Researches on the development on SiCf/SiC refractory composites for generation IV nuclear fuel cladding led the CEA to focus on the thermal behavior of these materials. In particular, knowingthe thermal properties is essential for their components design. Regarding the development of the sandwich" concept, whose complexity and geometry differ from the conventionally used at tubes,usual measurement methods are unsuitable.This PhD reports on the characterization and modeling of the thermal behavior of these structures. The first part concerns the identification of the global thermal parameters of the diferent layers of a"sandwich" sheath. To do so, a ash method is used and an experimental bench suitable for tubular geometries was developed. A new estimation method based on the combination of both collectedsignals in front and rear faces allows the identification of the thermal diffusivity of tubular composites using infrared thermography. The second part focuses on a virtual material approach, established todescribe the thermal behavior of a "sandwich" cladding, starting from the properties of the elementary components (bers and matrix). These properties, obtained using two different estimation methods,allows exploiting the measurements of two separate experiments based on infrared thermography.They are then used as data for the heat transfer modeling in these ducts. Confrontations betweenexperimental measurements and numerical results finally allow gaining insight into the in uence ofthe different key parameters governing the heat transfer
Monette, Simon-Pierre. "Caractérisation hydraulique et thermique d'une assistance ventriculaire". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ65589.pdf.
Brigui, Jamal. "Synthèse, caractérisation et comportement thermique de polystyrènes bifonctionnels". Saint-Etienne, 1992. http://www.theses.fr/1992STET4008.
Latournerie, Jérôme. "Céramiques nanocomposites SiCO : Synthèse, caractérisation et stabiblité thermique". Limoges, 2002. http://www.theses.fr/2002LIMO0046.
This work concerns the synthesis and the thermal evolution of polysiloxanes gels obtained by the sol-gel method. The aim of this study is to better understand the effect of the substituting groups bonded to silicon atoms on the cross-linking, ceramic yield and the thermal behaviour at high temperature. Two different types of precursors have been studied : trifonctional compounds RSi(OEt)3 ( where R=CH3, C2H3 and C6H5) and precursors that contained Si-H bonds obtained after polymerization of a mixture of methyldiethoxysilane and triethoxysilane in a variable amount (DhTh 1/1, 1/2 and 1/9). The first chapter concerns the study of hydrolysis and condensation reactions of different precursors by Raman spectroscopy. By following the kinetics of the disappearance of vSiO, we could access the intrinsic reactivity of hydrolysis reaction for of each precursor. These phenomena have been explained by steric, mesomer and inductive effects. In the second chapter, we studied the mechanisms of thermal conversion of polymeric gels into silicon oxycarbide. Thus the chronology of the main processes of mineralization in relation to the nature of the substituting group has been evaluated. The third chapter deals with the structural evolution of Si/C/O systems. We clearly established the importance and the domain of temperature of each reaction, which occurs above 1000°C, in relation to the composition of the materials. Carbothermal reaction has been studied and it shows SiO gas to be an intermediate product
Droval, Guillaume. "Élaboration et caractérisation de composites polymères conducteurs électrique et thermique". Lorient, 2006. http://www.theses.fr/2006LORIS068.
Focusing on further application in the field of ohmic heating, the aim of this work is to improve the thermal conductivity of heating systems (based on biphasic conductive polymer composites (CPC) – immiscible blend) without significantly altering electrical properties to ensure that the temperature gradient within the material decreases since that could, in a long run, damage the system. The applied approach allowed to study and control in an independent way the thermo-physical properties of each phase: an electrically conductive phase (high density polyethylene (HDPE) matrix with carbon black (CB) fillers) and a thermally conductive phase (syndiotactic polystyrene (sPS) matrix filled with various thermal micro particles such as aluminium oxide (Al2O3), aluminium nitride (AlN), talc or even boron nitride (BN) among others). The novel feature obtained from this study is the synergy of the electrical and thermal properties of the two phases. These new formulas maintain a self regulating capability (increase of the electrical resistivity as the temperature rises (Positive Temperature Coefficient – PTC effect) and double the heat dissipation. Finally, the thermo-electrical behaviour of optimized CPC in working process has been studied through experimental data and simulation models on benchmarks of pilot tests. These results are fully satisfying in the purpose of developing and designing these materials as self regulating heating elements
Mazhoud, Brahim. "Elaboration et caractérisation mécanique, hygrique et thermique de composites bio-sourcés". Thesis, Rennes, INSA, 2017. http://www.theses.fr/2017ISAR0024/document.
In response to environmental concerns, the use of hemp concrete has been developed in recent years and has shown its efficiency from a hygrothermal point of view. Its life cycle analysis underlines the environmental interest of hemp and shows that the most impacting component is the binder, usually lime-based. The aim of this thesis is to develop hemp-based composites by substituting lime with a less impacting mineral matrix. Several formulations are made with different binder matrices and different hemp content. On the one hand, the ThermO® commercial binder is used to produce "classic" hemp concrete, which are used as a comparative reference. On the other hand, binder matrices are developed based on washing mud fines. Claytec® commercial earth is also considered. After presenting the different raw materials selected for this study, the ThermO® binder is characterized with several water ton binder ratios. The washing mud fine stabilisation is investigated regarding mechanical resistance objectives. A stabilization with 5% of portland cement coupled with 5% of ThermO® is selected for the following development. This formulation does not significantly affect the thermal conductivity of the binder matrix, while allowing to achieve the fixed mechanical objectives. The composites made with the various selected binders have hemp I binder ratios ranging between 0.4 and 0.75, conventional ratio for roof, wall and floor applications. They are implemented by compact ion, which leads to densities ranging from 370 to 61 5 kg/m3 and porosities ranging from 70 to 81%. The mechanical. Thermal and hygric behaviors of the composites are investigated. The measured mechanical performances meet the requirements of the professional rules Construire en Chanvre, even for composites made with unstabilized fines. The sorption isotherms obtained are class II or III sigmoid, with higher water contents for composites made with ThermO®. The MBV values obtained show that the composites made with fines and with Caytec® earth are better hygric regulators than the composites made with ThermO® binder, respectively classified as excellent and as very good hygric regulators. The thermal performances of the composites allow a use in distributed insulation. At the dry point, the thermal conductivity mainly depends on the density, without impact of the type of binder. As ambient relative humidity increases, the thermal conductivity of ThermO®, binder-based composites is more impacted than that of other composites in connection with sorption isotherms. This study thus shows the relevance of the development of composites formulated with washing mud fine as a substitute tor lime
Okhrimenko, Larysa Mikolaivna. "Stockage d'énergie thermique par un composite zéolite/MgSO4-H2O : étude thermocinétique du système MgSO4 – H2O et étude expérimentale des composites". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEM001/document.
Exhaustion of fossil fuels and increase of energy demand, lead to growing interest in the development of renewable energies and energy efficient systems. Nevertheless, the gap between the supply and the demand of energy by renewable energies makes necessary the using a storage system. Among various thermals energy storage technologies, the composites formed by a porous matrix and a hygroscopic salt, allow to benefit advantage of both the adsorption/desorption capacities of the matrix and the chemical reactions of salt. The main difficulty to develop of such a system is the incomplete understanding of the involved physicochemical phenomena.The first objective of this thesis is to study the hydration and dehydration reactions of MgSO4 salt in presence of water vapor. Firstly, the physicochemical characterization of solids and isothermal and isobaric thermogravimetry experiments were carried out. It has been shown that the system is divariant and that the hydrates obtained are non-stoichiometric with localized water molecules. A thermodynamic model was developed and applied to the experimental data. In a second step, the kinetic studies of both the dehydration and hydration reactions were carried out. The rate limiting steps were defined, two kinetic models have been written and applied to the experimental results. Finally, various zeolite/MgSO4 composite materials have been synthesized. These materials have been characterized and their sorption capacity has been measured. The results show an increased sorption capacity, but only for water vapor pressures different from those used for thermal energy storage
Lalisse, Adrien. "Optimisation thermique de nanostructures plasmoniques : conception, modélisation et caractérisation". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066081/document.
Focusing light on the nanoscale in order to create intense optical or thermal nanosources is probably the main challenge facing the nano-optics community, in order to power up future devices. Metallic nanoparticles and their surface plasmon resonance are ideal optical or thermal nanosources.In this context, this thesis aims at providing a possible solution to the issues of thermal optimization at the nanoscale and nanothermometry.By carrying out numerical simulations, we were able to highlight the heat generation properties of titanium and zirconium nitrides, exceeding those of gold, which make them ideally suited in order to conceive and fabricate heat nanosources in the visible. We also managed to obtain a particle morphology inducing a maximum heating at a given wavelength : a three-branchs nanostar.We fabricated gold nanostructures by e-beam lithography in order to characterize them with photothermal holography. By exploiting the two kind of informations available with this far-field optical technique, the amplitude and the optical phase, we strove to quantify the temperature variations of gold nanorods. The photothermal holography setup based on amplitude delivered semi-quantitative temperature measurements, and the phase based-technique, still at a preliminary stage of developpement, proves to be a new and promising tool for the study of optical and thermal properties of plasmonic nanostructures
Émond, Josée. "Suivi et caractérisation de glaces fluviales par imagerie thermique". Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28213/28213.pdf.
Surface ice observations on the St. Lawrence River are needed to provide a safe and effective waterway, as weil as to study climate changes. Usually made locally, ice characterization is made on a reach of 250 km between Montreal arid Quebec City, from airbome thermal imaging. lee surface temperatures are acquired, and a heat transfer equation modeled through a finite-element model links these temperatures to ice thicknesses. lee characteristics, such as concentration, size and shape, are also obtained. Operationallirnits in the form of rain, snow and fog, are encountered, as weil as maximum detectable thicknesses due to the physics of heat transfer and to the model used. Overall, infrared imaging is a well-suited technology for drift ice observations on the St. Lawrence River, but it has its lirnits, just as any other technology.
Mourtada, Adel. "Caractérisation thermique des parois opaques et transparentes du bâtiment". Lyon 1, 1988. http://www.theses.fr/1988LYO19003.
Guedia, Guemo Gilles Romuald. "Modélisation et caractérisation thermique de machines électriques synchrones à aimants permanents". Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0023/document.
Permanent magnet synchronous machines are likely to break down due to poorly controlled heating. The goal of this study was to develop a generic and predictive thermal model to calculate the temperature of machines during the design phase simulating temperatures at various states. These states include: steady state, transient state, fault mode, axial circulating of a cooling fluid in the air-gap and high speed. The lumped parameter method was used to develop this generic thermal model. Meanwhile, a test bench and a prototype instrumented with thermocouples were manufactured to validate the model at the same time. Sensitivity studies of the results of the model to some parameters demonstrated that some convective coefficients, contact conductances and the thermal conductivity of the winding in the radial direction influenced the model. However, these parameters are poorly known, because empirical formulas or abacus are used to calculate them. Using, the prototype and the developed model, these parameters were identified. Three methods of identification were tested in order to find a strategy for the identification: the genetic algorithms method, the Gauss-Newton method and the Levenberg-Marquardt method. Many tests were done on the prototype. The measure of the temperatures on the specific place allows to identify these parameters and to validate the model
Rodrigues, Anthony. "Caractérisation des interactions entre un plasma non-thermique et des matériaux". Thesis, Poitiers, 2013. http://www.theses.fr/2013POIT2288.
The interactions between the active species generated by a non thermal plasma and various material surfaces have been studied in this work. In a first part, biopolymers coming from biomass have been the subject of our investigations as they offer a great reservoir for a platform molecule, glucose, from which valuable chemicals can be generated. More specifically, the effects of a dielectric barrier discharge plasma on the structure and depolymerization of inulin, cellulose and starch were evaluated. For that purpose, the electrical and chemical characteristics of the plasma discharge were varied and their effects on the biopolymers evaluated in order to understand the reaction mechanisms. Our results showed that a plasma pre-treatment increased considerably the final monomer yield (in glucose and fructose) compared to the untreated starting material (84 and 54 % yield in glucose from plasma treated starch and cellulose, instead of 65 and 1 % for the same untreated samples). This effect could be partly explained by the depolymerization of the amorphous areas of the polymers by and acid attack within the plasma discharge.In a second part, the study focused on the removal of VOCs by coupling non-thermal plasma and inorganic materials. For this purpose, we designed and implemented an innovative apparatus. It consists of a plasma-catalyst reactor with controlled atmosphere that allows the analysis of the catalyst surface by IR spectroscopy (DRIFT). The decomposition of four VOCs (isopropanol, acetone, ethanol and toluene) adsorbed on different metallic oxides (y-Al2O3, CeO2 and TiO2) placed within the discharge area have been studied in situ using this method. The first results have enlightened the decomposition pathways of the different VOCs
Gusarov, Boris. "PVDF polymères piézoélectriques : caractérisation et application pour la récupération d’énergie thermique". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT091/document.
This work deals with the characterization of piezoelectric polymers PVDF and its composites with shape memory alloys, for thermal energy harvesting applications. First, we discuss current advancements on energy harvesting technologies as well as their economical interests. Typical values of energy that can be generated are given together with energies typically needed for applications.Particular attention is given to the functioning principles of pyroelectric and piezoelectric materials. PVDF and shape memory alloy NiTiCu are also introduced.Custom characterization techniques are introduced to characterize PVDF piezoelectric properties relevant to generator applications and to evaluate its suitability for thermal energy harvesting. Since PVDF is a very flexible material, four-point bending, tube bending and a tensile machine experiments are used to study its piezoelectric response in quasi-static mode, as well as changes in piezoelectric properties with increased strain. Self-discharge measurements under various applied electric fields, temperatures and strains are performed to study the stability of material.A concept of composite energy harvesting, utilizing two materials of different families, is introduced. Here, we propose the coupling of piezo-/pyroelectric material and shape memory alloy. The pure pyroelectric voltage is combined with generated piezoelectric voltage, induced by shape memory alloy transformation, to increase the total energy generated by the system during heating. The proof of concept is shown first for ceramic PZT-based semi-flexible material and then for fully flexible PVDF.Finally, a power management circuit was designed and integrated with the PVDF energy harvester. High generated voltage peaks at heating are lowered by a two-step buck converter to a useful stable output voltage. Output energy are used to power a wireless emission card. Thus, a complete power generation chain from temperature variations to data emission is presented.The results of this work concern a wide range of applications, especially modern autonomous wireless sensors and Internet of Things objects, with low profile, high mechanical flexibility and low maintenance costs
Yuan, Shifeng. "Caractérisation des surfaces découpées par laser et modélisation thermique du processus". Lyon, INSA, 1989. http://www.theses.fr/1989ISAL0008.
Tankpinou, Kiki Yvette sedjro. "Caractérisation minéralogique, thermique et microscopique des sols fins en technique routière". Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0227/document.
To help reduce the problems caused by phenomena due to the shrink-swell soil in the depression of the Lama in southern Benin, we have undertaken research in order to control the behavior of these soils. Six soil samples, including four clay from this area were taken. Different types of tests were performed: a macroscopic characterization concerning mainly mechanical and geotechnical properties and microscopic tests taking into account the chemical, thermal, microstructural and mineralogical analysis. The soils studied consist of different clay minerals. The fibrous structure is at the origin of a particular macroscopic behavior detected by the free swell test. The tests confirmed the potential for swelling and shrinking of some soils that are causing heavy damage.Three soils treated with different contents at Binder Hydraulic Road, were subjected to several tests. The results show that these soils are distinguished by the acquired mechanical performance and may be used at different levels of the floor according to binder content.Also, the different methods revealed specific facets of fine soil treatment study. Mainly, we noted that the information provided by the observations scanning electron microscope, thermal analysis and the analysis of diffraction X-Ray are very important and helped complete the analysis of geotechnical results for soil treatment. In sum, geotechnical characterization methods used to get a general idea of the swelling potential, but for large-scale studies, conducting microscopic studies is paramount
Pradere, Christophe. "Caractérisation thermique et thermomécanique de fibres de carbone et céramique à très haute température". Phd thesis, Bordeaux, ENSAM, 2004. http://pastel.archives-ouvertes.fr/pastel-00001547.
Belhassein, Betty. "Caractérisation et modélisation de la thermique d'un moteur Diesel et de sa ligne d'échappement". Ecole centrale de Nantes, 2014. https://hal.archives-ouvertes.fr/tel-01207627.
This Ph. D. Thesis deals with the characterization and modeling of heat transfers in the exhaust line of a turbocharged Diesel engine when working in steadystate and transient conditions. To deal with this issue, a methodology is developed based on specific experimental testing and the use of system simulation. Concerning transient operation, a temperature reconstruction method is tested. For using this method, thermocouples of different diameter are put in two experimental test benches : a pulse generator and an engine test bench. The dynamic error can be characterized by the pulse generator. Experimental testing is done on the engine test bench to characterize the heat exchange in the exhaust line, especially in the turbine and in the aftertreatment systems. To characterize the influence of the latter, two exhaust lines are studied. The turbocharger and the exhaust lines are modeled with a 0D approach taking into account the heat transfers and validated with the experimental data. The turbocharger modeling is compared to a reference approach in order to estimate the contribution of the proposed approach in terms of representativeness of the heat transfers
Jorez, Sébastien. "Développement d'instrumentation et de méthodologies pour la caractérisation thermique et thermomécanique de composants électroniques". Bordeaux 1, 2001. http://www.theses.fr/2001BOR12425.
Gavérina, Ludovic. "Caractérisation thermique de milieux hétérogènes par excitation laser mobile et thermographie infrarouge". Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0012/document.
Nowadays, composite materials are widely used in the aeronautic and aerospace industries because of their high mechanical resistance. However, they have a large heterogeneity due to the fiber and matrix they are made of. In this way, for many years, the TIC team «Thermal Imaging Fields and Characterization » from TREFLE department of I2M laboratory develops methods to measure thermal in-plane properties of heterogeneous materials such as inverses (integral transforms, double singular value decomposition…) or experimental (Flash, laser diode…) methods. The recent progress made in optical control, lasers and infrared (IR) cameras enables the development of a new scanning system (based on galvanometer-mirror) which allows the easy control of a laser hot spot spatial and temporal displacements over a plane surface. The low cost of laser diodes and optical control (galvanometric mirror) systems allows to develop a laser scanning system fixed on a test bench. We can revisit the different types of thermal excitation and realize infinite spatio-temporal combinations of thermal excitations by laser method. This is one of this thesis aims. New inverse methods based on the thermal response to an instantaneous point source heating, and temperature fields separability, have been proposed. These methods allow to estimate the thermal diffusivity tensor along the main axes of anisotropy, but also out of those axes, where it is possible to estimate the anisotropy axes orientation when the heat transfer takes place out of the image axes. These methods have produced interesting results in view of their simplicity. Moreover, they made it possible to obtain in-plane thermal diffusivities maps because, compared to the other methods, they allow to obtain, locally, thermal diffusivity tensor estimations by getting a surface heat flux map using the laser optical scanner
Bui, Anh Tuan. "Caractérisation et modélisation du comportement des matériaux magnétiques doux sous contrainte thermique". Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00857546.
Cong, Weimin. "Préparation, caractérisation et stabilité thermique de différentes phases de l’hydrure d’aluminium (alane)". Poitiers, 2011. http://www.theses.fr/2011POIT2275.
Aluminum hydride or alane AlH3 is a very important material as energetic additives in rocket propellants. There are at least eight AlH3 phases found in the literature. But in fact only the most stable α-AlH3 (Hf° = -11. 4 kJ mol-1) can be a candidate for the potential utilization. The safe, reliable, low toxic and low cost synthesis methods of pure α-AlH3 attracted numerous studies. The alane samples are synthesized using an organometallic synthesis method in two steps : (i) preparation of a soluble alane complex solvated by ether; and (ii) removal of ether to get the non-sovated alane. 1) 3 LiAlH4 (in ether) + AlCl3 (in ether) (+ LiBH4) 4 AlH3·Et2O (solvated) + 3 LiCl(s) 2) AlH3·Et2O (solvated) (heat treatment / crystallization in solvent solution) AlH3(s). With changing heat treatment conditions and crystallization condition, kinds of alane samples are prepared. These samples are characterized with powder X-ray diffraction, Scanning electron spectroscopy, Raman scattering microprobe and NMR (27Al and 1H, for the study of alane solvated solution in ether). The decomposition performances of the samples are investigated by TGA-DTA and In-situ X-ray diffraction. Among these samples, pure γ-phase alane and pure α-phase alane are obtained successfully. The heat treatment temperature and the crystallization conditions in solvent solution play very important roles in the pure γ and α phase alane preparation respectively. After the stabilization treatment, α-phase alane are well stabilized. The samples are very stable until the main decomposition. The pure α-phase alane sample is prepared with larger scale (from 2 g to 6 g) and is repeatedly synthesized successfully. It has proved this preparation method is reliable and reproducible
Verdy, Christophe. "Structures multicouches mises en forme par projection thermique : élaboration, caractérisation et applications". Besançon, 1998. http://www.theses.fr/1998BESA2077.
The aim of this work was to develop an experience about the building of high mechanical characteristics multi-layered structures by thermal spraying. The first part of the study consisted in studying the characteristics of several vacuum thermal spray metallic materials : Nickel based, superalloys Astroloy and Inconel 625, Titanium based TA6V4 and Copper based CuAgZr alloys, materials which were then considered for the multi-layered structures. Thick deposits, with high mechanical characteristics, i. E. Close to forged or HIPed materials, were obtained. The concept of multi-layered structures was then tackled within the framework of two practical situations : the structure of a combustion chamber wall submitted to a very high heat flux and the structure of a blade containment system for turboengines with the capability to withstand the perforation of high kinetic projectiles. The building of such structures imposes strong constraints about the choice of materials because thermal spray durations are likely to exceed one hour at high temperatures and also because further thermal treatments increase the importance of interdiffusion phenomena. It was shown that interdiffusion between deposits can be either profitable with the creation of a functionally graded material, or detrimental with the creation of fragile intermetallicd phases
Ji, Gang. "Elaboration et caractérisation de revêtements nanocristallins Fe-40AI préparés par projection thermique". Besançon, 2003. http://www.theses.fr/2003BESA2034.
Nanostructured Fe-40Al coatings were prepared by High Velocity Oxy-Fuel (HVOF) spraying from milled powder. The as-sprayed coatings as well as the milled powder were examined by X-Ray Diffraction, Scanning Electron Microscopy, Transmission Electron Microscopy, Differential Scanning Calorimetry and Mössbauer Spectroscopy to improve the understanding of structure formation in such coatings; in particular, to clarify the origin of the nanostructures. The relationships among the process parameters, the microstructure and the coating properties (hardness and corrosion) were also investigated by the variation of the size of the feedstock powder. The resultants indicate that the coatings show a bimodal structure where 3D nanograins, resulted from a partial crystallization of the starting powder, can be essentially conserved in non melted particles. Alternatively, because of the rapid solidification, the 2D nanograins can be formed in fully melted particles. Finally, the hardness/corrosion balance can be optimized by a good selection of powder size feedstock
Monin, Valéry. "Elaboration et caractérisation de segments automobiles hautes performances élaborés par projection thermique". Besançon, 2000. http://www.theses.fr/2000BESA2071.
The drastic working conditions of diesiel engines imply piston ring manufacturers to elaborate wear resistant coatings for top position piston ring. The results presented in this study concern the elaboration and characterization of atmospheric plasma sprayed deposits for piston ring. This study received a financial support from Perfect Circle Europe. Firstly, the piston ring-cylinder environment is presented. The consideration of the engine working conditions and the piston ring-cylinder wear mechanisms leads to the definition of a new plasma sprayed piston ring coating : a Mo matrix with a hard TiN reinforcement. The second part is dedicated to the optimization of the elaboration of the previous coating (Mo-NiCrBFeSi) and its tribological and physico-chemical characterization. Wear mechanisms analysis shows the importance of the interlamellar cohesion for tribological applications. The third part concerns the elaboration of a Mo-TiN based plasma sprayed coating from agglomerated and blended powders. Tribological results show the efficiency of the hard phases TiN associated with a NiCrBFeSi binder. Finally, an electrochemical approach is used to estimate the chemical resistance of the coatings in a corrosive environment
Meyruey, Gwenaëlle. "Caractérisation et modélisation du vieillissement thermique d’un composite à base d’alliage d’Aluminium". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI092.
Precipitation-strengthened alloys as Al-Mg-Si alloys reinforced with ceramic particles are an appropriate alternative for industrial applications. The precipitation sequence in Al-Mg-Si alloys is particularly complex when Silicon is in excess with respect to the Mg2Si composition and it is expected to be modified by the presence of the ceramic reinforcement. This is why, for industrial applications, under certain use conditions, it is fundamental to be able to predict the evolution of the microstructure in the alloy and the consequences on mechanical properties. The present work is devoted to the study of an age-hardenable Al-Mg-Si aluminium alloy which, can be facing temperatures between 100°C and 350°C in use conditions. This material is characterized by a complex precipitation sequence due to Silicon-excess and ceramic particles. The main objectives of the work are the following: 1) To describe how the microstructure evolves in the Al-Mg-Si alloy with silicon excess studied, with or without reinforcement, during a long storage period at a temperature between 100°C and 350°C. Then, it appeared necessary to describe the evolution of the mechanical properties in the same conditions but starting from a T6 state (corresponding to peak aged conditions). 2) To predict these evolutions (microstructure and strength) using an appropriate model. It was highlighted that the high silicon excess in the studied alloy leads to a simultaneous precipitation of several semi-coherent phases. Their precipitation has been predicted thanks to a KWN-type model based on classical nucleation-growth theories, validated by the experiments, and implemented considering: 1) the competitive precipitation between coherent et semi-coherent phases, 2) the rod-shape morphology of precipitates with a variable aspect ratio. This model has been used for the prediction of the Time-Temperature-Transformation diagram of the alloys and its composite considering the acceleration of the precipitation kinetics observed and attributed to the high dislocation density resulting from the presence of ceramic particles. Finally, 2 methods for the mechanical properties prediction have been compared: 1) a JMAK-type empirical approach 2) a physically based approach. The JMAK approach allowed us a quicker and easier prediction of the loss of hardness from the T6 state, for alloy and composite, during isothermal and non-isothermal treatment. Despite a prediction close to the experimental results, this approach cannot give us information about the physical mechanisms responsible for the observed mechanical variations. Then, a physically based approach taking into account the predictions of the precipitation model was used for the yield stress estimation during aging with a micromechanical model. This approach gave encouraging results and could be a powerful tool for the prediction of the strength during industrial use conditions
Boussatour, Ghizlane. "Caractérisation diélectrique et thermique de films biopolymères pour l’électronique flexible haute fréquence". Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I015/document.
Biopolymer materials attract significant attention in many fields where they tend to replace petrosourced polymers. Thanks to their properties, such as biocompatibility, biodegradability, flexibility and lightness, biopolmyers are also increasingly used in many electronic applications. Nevertheless, their possible integration into high-frequency electronics requires the study of important properties such as thermal conductivity and dielectric complex permittivity. In this work we are interested in two biopolymers in particular, poly lactic acid (PLA) and cellulose palmitate (CP). The extraction of the properties of these materials is carried out through the implementation of two methods. The means selected are the 3ω method for the thermal conductivity and the two-line method for the dielectric complex permittivity. This latter is measured in the frequency band 0.5 - 67 GHz. These two characterization techniques require the realization of metal lines on the surface of the biopolymer films. Since biopolymers are not compatible with classical photolithography method, an alternative processes have been developed to meet this technological challenge. This experimental work is accompanied by modeling studies on both aspects, estimates of the thermal conductivity and the complex dielectric permittivity of the investigated materials. The comparison of the proposed analytical and numerical models with the experimental data shows a good understanding of the problem of characterization of these biopolymers
Ahose, Komla Dela Mawulawoe. "Caractérisation et modélisation du vieillissement thermique d'élastomères chargés par une approche multiphysique". Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0726/document.
This study mainly concerns the thermal aging phenomenon in amorphous synthetic rubbers, initially vulcanized and filled with carbon blacks. On the basis of one material formulation, we study: the impact of the process (vulcanization condition), the influence of the chemo-physical evolution of the cross-linked network on the mechanical behavior and the influence of a permanent mechanical load during aging. Mechanical characterizations (cyclic, relaxation and hydrostatic tests) and chemo-physical ones (variation of mass and volume, swelling in solvent) are realized in order to quantify the impact of ageing. The main phenomena observed is an increase of the crosslink density (maturation of polysulfides to monosulfide or disulfide crosslinks). From a general point of view, we can formulate many hypothesis from the experimental characterizations (isotropy, non-dependence of some physical properties on ageing, etc.). For the modeling, we have adopted a themo-chemo-mechanical approach that is based on the thermodynamics of irreversible processes and the introduction of internal variables in order to phenomelogically describe on one hand the nonlinear mechanical behavior at finite strain (nonlinear viscoelasticty, Payne effect, etc.) and on the other hand the chemo-physical evolution of the macromolecular network (which depends on temperature and mechanical state). This approach has permitted to introduce a reciprocal coupling between chemo-physical and mechanical states
Soanen, Nastasia. "Caractérisation et modélisation de la culture de la microalgue Chlamydomonas reinhardtii et mise en place d'un photobioréacteur miniaturisé pour l'étude quantitative de la croissance de micro-organismes photosynthétiques". Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAS023.
Funded by two separate research projects (AlgoH2 (ANR) and MELiSSA (ESA)), this work, conducted within the GePEB axis, is focused on the application of knowledge models of energetics of living cells for cultures of photosynthetic microorganisms. The first study was conducted on the microalga Chlamydomonas reinhardtii, in order to optimize the bio- production of dihydrogen. The work has been to gather the whole metabolic reactions existing in the cell in order to carry out a stoichiometric and thermokinetic study of the cellular functioning of growth and hydrogen production phases, the objective being to understand, control and optimize the production of hydrogen in photobioreactor. A contribution of this work is also to assemble a consistent database, bringing together the properties of formation of compounds involved in the cellular functioning, in order to apply the rules of calculations of thermochemical equilibria to compounds of cellular metabolism. As a second part of the study, a mini-photobioreactor developed in the lab in 2003 has been optimized and modernized. This mini-PBR allows realizing fast analyzes on the functioning of the photosynthesis. The design in two compartments separated by a membrane presents the interest extrapolating the behavior of the cyanobacterium Arthrospira platensis in conditions of microgravity. A model of knowledge of the photosynthesis, grouping the radiative transfer and the kinetics of growth on nitrate source had previously been developed. Comparing the preliminary tests carried out in Roux flasks on different nutrient nitrogen sources with model allowed better understanding of the cellular metabolism and further improvements of the mini-PBR
Collet-Foucault, Florence. "Caractérisation hydrique et thermique de matériaux de génie civil à faibles impacts environnementaux". Rennes, INSA, 2004. http://www.theses.fr/2004ISAR0016.
This work deals with hydric and thermal characterization of cob, hemp and lime coating, hemp mortar and hemp wool. The first part deals with environmental quality of building materials and presents the ones studied. Their structural physical characteristics are given. The wet fixing and transfer are then studied by sorption and permeability measurement. The results obtained are compared with the porous structure and are coupled in order to calculate the isothermal hydric diffusivity coefficient. Lastly, the thermal characteristics of the materials are measured for three wet contents. The results are compared with those obtained for other materials. Simulations enable to compare the heating needs of a building with walls made of different materials (insulated concrete blocks, cob, hemp mortar). The results show that the heating needs for the studied materials are similar for lower environmental impacts all the building life cycle long
Gauthier, Sébastian. "Caractérisation thermique de la matière par la méthode 3ω". Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2012. http://tel.archives-ouvertes.fr/tel-00826953.
Blanchard, Florent. "Nouveaux peroxydes et peroxo-oxalates à base d’uranium, précurseurs d’oxydes : synthèse et caractérisation". Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL10108.
One of the current researches on future nuclear cycle is spent nuclear fuel treatment and recycling, where actinides mixed solids are prepared as raw materials for nuclear fuel refabrication. After separating-purification cycle during spent nuclear fuel treatment, the conversion step of actinides from solution to mixed oxide is one of the key stages. Currently, plutonium is recovered by oxalic precipitation and numerous studies on its precipitation and oxalate decomposition have been done. Meanwhile, in the case of uranium, a uranyl peroxide is precipitated. Therefore, a route to investigate is the use of peroxides or peroxo-oxalates as oxides precursors. The main goal of this study is to study the feasibility of such method. In a first step, examination of NH4+/UO22+O22-/C2O42- system has highlighted the evidence of many peroxides or peroxo-oxalates formed as polyanions or nanoclusters. These entities lead to uranium oxides after calcination. In a second step, using uranyl nanoclusters, mixed uranium - lanthanide or uranium - thorium compounds were prepared and characterised by single crystal and powder X-ray diffraction, ICP-AES analysis, electron microscopy, UV-Vis and IR spectroscopy. Their decomposition in mixed oxides has been studied under different atmospheres
Briant, Tristan. "Caractérisation du couplage optomécanique entre la lumière et un miroir : bruit thermique et effets quantiques". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2003. http://tel.archives-ouvertes.fr/tel-00004972.
Nous avons mesuré le bruit thermique du miroir et suivi son évolution temporelle dans l'espace des phases. Nous avons refroidi le miroir en exerçant une force de friction froide et obtenu une compression du bruit thermique dans l'espace des phases.
Une étude spatiale des modes acoustiques internes a été réalisée pour différentes géométries du miroir, en balayant une force de pression de radiation sur la surface du miroir. Les résultats valident les modèles théoriques utilisés pour les interféromètres gravitationnels et permet de définir une géométrie favorable à la démonstration des effets quantiques du couplage optomécanique.
Nous présentons également une étude théorique des bruits thermiques et quantiques dans un nouveau type d'antenne gravitationnelle, constituée de deux sphères imbriquées.
Bensaid, Samir. "Contribution à la caractérisation et à la modélisation électromagnétique et thermique des matériaux composites anisotropes". Nantes, 2006. http://www.theses.fr/2006NANT2107.
The carbon fibre composite materials cover a lot of manufacturing industries. To assemble parts of these composites several techniques are used. The technique using electromagnetic induction is very interesting; for his advantages such as the fast, without contact and localised transmission of energy to the assemblage interface. The goal of this thesis is to model in 3D, the induction heating of composite materials by taking into account of the anisotropy. Owing to the problem of the scale factor, these materials are replaced by homogeneous equivalent materials; so their electromagnetic and thermal properties are obtained either by using the homogenisation or experimental methods. In this work, to identifying the electric conductivity, one proposed an experimental method based on the impedance measurement. In addition, in our case, these materials are in the form of plate with very small thickness compared to the other dimensions. The shell elements associated to the nodal finite elements are then used. Two models have been developed, a monolayer anisotropic shell elements model applied to composites of unknown structures and a multi-layer model dedicated to the laminated composites with oriented structures. A confrontation between the simulation and experimental results (in induction heating) gave an acceptable difference. These models are applied to improve an industrial application of an induction assembly of composite materials
Lecœur, Edwige. "Étude de nouveaux retardateurs de flamme pour étoffes cellulosiques : formulations, procédés, caractérisation et durabilité". Lille 1, 2002. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2002/50376-2002-259.pdf.
Di, Martino Françoise. "Synthèse et caractérisation de carboxylates métalliques produits de traitement de conversion de surface". Nancy 1, 2002. http://www.theses.fr/2002NAN10278.
This work is about synthesis and characterisation of metallic carboxylates, products of surface conversion treatment. These compounds are studied for the protection of metals against atmospheric or aqueous corrosion. Their crystallographic and thermal properties are studied here. The structures of zinc carboxylates with 7, 8, 9, and 10 carbon atoms have been resolved as those of magnesium, gadolinium and lead heptanoates. Thermal analysis has allowed to identify numerous transformations occurring before melting : they are structural transitions common in zinc carboxylates and crystal - liquid crystal found in lead carboxylates. Otherwise, other compounds stemming from the study of carboxylates coatings are also studied, some mixed compounds associating two different anions : the zinc hepta-decanoate and the zinc hydroxy-heptanoate
Barbier, Benjamin. "Bilan thermique et caractérisation géochimique de l'activité hydrothermale du volcan Rinjani, Lombok, Indonésie". Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210140.
Les sources thermales situées autour du Gunung Baru (cône volcanique situé dans la caldera) ont une composition chimique en éléments majeurs et une composition isotopique proche de celles du lac volcanique indiquant qu’elles sont essentiellement le résultat du recyclage du lac par le système hydrothermal. Les variations de compositions entre les différentes sources ont permis de montrer que leurs compositions est le résultat du mélange entre un fluide hydrothermal profond de composition neutre chlorure, dont la température a été estimée à 270°C, et d’un fluide plus superficiel riche en magnésium et en sulfate.
Le flux de dioxyde de carbone à la surface du lac a été estimé à l’aide de la méthode de la chambre d’accumulation et par calcul à environ 2300 t/j, ce qui représente un apport significatif de gaz. Cependant, comme le lac présente une structure polymictique, le risque d’accumulation de dioxyde de carbone en profondeur et donc d’éruption limnique peut être exclus.
Pour la première fois dans cette thèse, le modèle d’estimation des flux thermiques émis par les lacs volcaniques mis au point par Stevenson (1992) a été contraint par des mesures des paramètres météorologiques mesurés en continu, ce qui a permis de valider le modèle. De plus, nous avons pu montrer que l’essentiel des variations de températures des lacs volcaniques est dû à des variations météorologiques. En utilisant le flux thermique plutôt que la température, il est dès lors possible d’avoir accès à des variations de l’activité volcanique.
Le flux thermique estimé pour le lac du Rinjani est de 1700 MW, ce qui représente le flux le plus élevé jamais mesuré sur un lac volcanique aérien. Ce flux thermique est aussi plus élevé que le flux thermique mesuré sur des lacs de lave à 800°C. Ce paradoxe apparent s’explique par la plus grande dimension des lacs volcaniques, la capacité calorifique de l’eau quatre fois plus importante que celle du magma et la viscosité de l’eau 1 million de fois inférieure, ce qui fait de l’eau un excellent fluide caloporteur pour transporter les calories vers la surface.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Salim, Shirazy Mahmood Reza. "Caractérisation du transport fluidique et thermique dans les mousses métalliques capillaires en cuivre". Thèse, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6141.
Testu, Amélie. "Dispersion thermique dans des milieux granulaires : caractérisation à coeur et en proche paroi". Vandoeuvre-les-Nancy, INPL, 2005. http://docnum.univ-lorraine.fr/public/INPL/2005_TESTU_A.pdf.
Heat transfer in a granular media through which a fluid is flowing is called thermal dispersion. It results from a combination of diffusive and convective heat transfer. The control of thermal dispersion is a critical point each time strongly endo- or exothermic chemical reaction in heterogeneous catalysis occurs. In this type of situation the control of the chemical conversion and/or of the lifespan of the catalyst is of prime importance. This work relates to the experimental characterization of thermal dispersion in granular media first in the core region and then in the near-wall region. In the first part of this work, a bed made up of granular medium (glass spheres or catalyst support) has been constructed. An air flow produced by a downstream fan goes through this bed. The bed is heated by Joule effect (time step) thanks to a metal wire perpendicular to the flow. The transient temperature responses are measured by several thermocouples. A specific inversion technique makes the estimation of the two thermal dispersion coefficients possible. Experimental correlations explaining the variation of the lateral and longitudinal dispersion coefficients with fluid velocity have been constructed on dimensional analysis considerations. They derive from the measurements on the glass beads/air and support of catalyst/nitrogen systems (use of dry nitrogen allows to get rid of the hygrophilic character of the micro-porous grains). The last part of this work relates to study of the thermal effects in the near wall region (effects caused by the hydrodynamic channelling phenomena). A new experimental set-up, with heating by a plane foil resistance on the wall and thermocouples inserted in the granular medium, has been built. Temperature measurements highlights the wall-effects. A new analytical model, that will make simulations of a two layers porous medium (core and near-wall regions) has been developed
Lefort, Eric. "Caractérisation des bifurcations et de la dynamique d'une lentille thermique par analyse spectrale". Rouen, 1987. http://www.theses.fr/1987ROUES019.
Bagui, Farid. "Caractérisation de la dynamique d'un échangeur thermique à contre-courant et synthèse d'observateurs". Rouen, 1998. http://www.theses.fr/1998ROUES004.
Ghorbel-Feki, Halima. "Elaboration et caractérisation de revêtements composites (Apatite-Alumine) sur métal par projection thermique". Thesis, Belfort-Montbéliard, 2016. http://www.theses.fr/2016BELF0304/document.
A considerable amount of research already focused on ceramic biomaterials given their chemical stabilityand high mechanical strength. On the one hand, Fluorapatite (Fa) has recently attracted some attention as analternative to pure hydroxyapatite (Hap) as coating on metallic implants, given its chemical composition which issimilar to the bone mineral and therefore its excellent biocompatibility. On the other hand, alumina is known for itsexcellent bioinertia and is also one of the most widely investigated bioceramics. In this frame, the aim of our workwas to investigate Al2O3-Fap and Hap-Fap composite coatings deposited on stainless steel substrates usingSpraying processes (APS and SHVOF). The mechanical, micro-structural, tribological and biological (in Vitro and inVivo tests) properties of these composite coatings are determined and analysed in order to determine their possibleuse as surigical implant materials
Lemeunier, Franck. "Caractérisation et modélisation des transferts de chaleur lors de l’impression en transfert thermique". Nantes, 2015. https://archive.bu.univ-nantes.fr/pollux/show/show?id=d447cae0-5949-4bb1-9847-c77358f8890f.
Thermal printing process is a commonly used in manufacturing for the printing of labels and bar codes. Heating generated by micro-heaters is transferred to the inked ribbon. The ink melts which involves its transfer to the paper or either format. A higher printing quality is necessary. To success in the numerical information (bar codes) reading. The variety of inks and formats, the wide range of the operating speed and the diversity of printing heads and thermal printers make delicate the control of process. The analysis and modelling of thermal transfers involved in printing process are central in this study. In this way, the whole of elements of printing system (printing head, ribbons and formats) are characterized. An industrial printer has been instrumented with mechanical and thermal sensors. Many experiments are performed with several printing conditions. The experimental data base obtained has been used to feed and validate the model of the overall system. The model takes into account the multilayers structure constitutive of this multi-scale system. It has the required numerical precision to reproduce the speed of phenomena evolution. The definition of a printing criterion exclusively based on thermal consideration was associated to the model to develop a virtual printer
Zribi, Aymen. "Fluxmètre thermique : conception, modélisation, réalisation et caractérisation. Mesures de températures et de densités de flux thermiques". Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2085/document.
For future applications in the field of low-temperature energy have sting in microsystems, knowledge of wall heat transfer is of great importance. These measurements are carried out using specific sensors which makes possible to know the total heat flux exchanged between walls and the surrounding environment. This study concerns the development of a gradient heat flux sensor compliant with their requirements associated with thermal machines such as micrometric Stirling engines. Six types of heat flux sensor with resistance temperature detector have been developed from different materials, with various geometries and shapes of sensing elements. An electro thermal study, taking into account the self-heating effect, was carried out and experimentally validated. The fabrication and characterization techniques, mainly carried out in clean rooms, allowed to produce numerous thin-film sensors. Specific housings for these sensors have been developed. These heat flux sensors, whose resistances have been calibrated with a highly accurate reference probe, also allow measuring the temperature. To measure the heat flux density, two methods were tested. The first method is indirect : it consists in measuring the temperature gradient using two platinum resistance probes. The second method is direct : it is based on heat flux calibration. The calibration and measurement benches have been modeled. Then, the experimental and numerical results have been compared. Finally, the influence of the sensor intrusion on the thermal fluxes distribution in the investigated sample, with or without a specific housing, has been studied
Bouache, Toufik. "Comportement thermique et caractérisation des échanges interfaciaux d’un frein à disque par approches théorique et expérimentale". Paris 10, 2006. http://www.theses.fr/2006PA100122.
The work developed in this thesis contributes to the knowledge of the thermal behaviour of a disc–brake system. The problem is studied from three different approaches: analytical, numerical and experimental. An analytical solution has been developed to determine the 3D steady temperature distribution in the disc. Three-dimensional numerical simulations of the transient state have also been performed. The results enable us to analyze the evolution of temperatures and to deduce from them the thermal gradients. These gradients are fundamental for the study of the thermomechanical behaviour of the system (constraints, deformations, effectiveness and wear). Two inverse models are developed to determine the temperatures and the contact parameters at disc-brake pad interface (local heat partition coefficient and thermal contact resistance). Measurements by thermocouples were taken using an experimental device mounted on a lathe. The experimental results are then used for the procedure of contact parameters estimation
Demilecamps, Arnaud. "Synthèse et caractérisation d’aérogels composites à base de polysaccharides et de silice pour la superisolation thermique". Thesis, Paris, ENMP, 2015. http://www.theses.fr/2015ENMP0029/document.
Improving the thermal insulation of materials is a key challenge to lower global energy consumption and greenhouse effect gas emissions in the coming decades. This thesis focuses on the preparation and characterization of nanostructured composite materials combining the good mechanical properties of bio-aerogels with the excellent thermal insulation properties of silica aerogels. Two polysaccharides were used to make bio-aerogels: cellulose and pectin. Two strategies aiming to elaborate composite materials were investigated: “one-pot” process and impregnation of a porous “wet” polysaccharide matrix by polyethoxydisiloxane. Drying with supercritical CO2 yields the composite aerogels. While the one-pot method gave micron-sized silica particles embedded in a porous cellulose network, impregnation process allowed obtaining a nanostructured interpenetrated network of cellulose and silica. The specific surface area was 700-800 cm².g-1, the mechanical properties improved as compared to neat silica aerogels and thermal conductivity lower than that of cellulose aerogels. Using a chemically hydrophobized cellulose, tritylcellulose, as the impregnation matrix, hydrophobic composites were obtained showing a contact angle with water of 133° and thermal conductivities of 0.021 W.m-1.K-1. Aerogels from cross-linked pectin and their composites with silica show extremely low densities (around 0.05 g/cm3 for the neat pectin aerogels) and thermal conductivities in the 0.013-0.022 W.m-1.K-1 range
Keruzoré, Nicolas. "Caractérisation thermique de l'équipement roue et frein aéronautique hautes performances par voies théorique numérique et expérimentale". Thesis, Paris 10, 2018. http://www.theses.fr/2018PA100127.
For the equipment manufacturer who develops aircraft wheels and brakes, the thermal behavior of the equipment refers to a major reference design point. This discipline is today at the center of concerns, because the designer is challenged on the system mass improvements. As a result, the temperature limits are more frequently reached, which must now be anticipated as early as possible.The pre-design phase should now also allow avoiding design iterations. However, the conditions under which the system operates and its thermal behavior, are poorly understood and poorly controlled. The predictive nature of the numerical simulations used to design the structure, depends directly on the model’s accuracy and on the in service boundary conditions imposed to the system.Today, Safran does not have any enough reliable tool or means to predict the thermal behavior of the Wheels & Brake assembly right from the pre-design phase. It is known that the design of the brake and the wheel have a reciprocal influence on the thermal kinetics of the system. Knowing how to predict the thermal behavior of the product, in response to stresses requested by the aircraft manufacturer, allows upstream technological choices whose impact on the thermal kinetics will be known. Thus, the design is disregarded of possible design iterations that could delay the aircraft certification by several years.The purpose of this thesis is to propose solutions to qualitatively reproduce the thermal behavior of an aircraft braking system, taking into account physical parameters associated with technological solutions. We also illustrate that these tools are also a way of knowing the conditions under which the system operates, when one knows in advance its temperature response by taking the problem in the opposite way