Дисертації з теми "Thermo-rheology"
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Brown, Tracy. "Investigation of the rheology, cure kinetics, and thermo-mechanical properties of GRC-A loaded with zeolites." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 2010. http://digitalcommons.auctr.edu/dissertations/256.
Derouineau, Thibault. "Synthèse et étude de polymères thermo-associatifs pour le domaine des lubrifiants." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLET018.
Controlling the viscosity of engine lubricants is a key issue to reduce the fuel consumption of engines. A new approach based on the use of thermo-associative polymers has been developed in order to compensate the natural loss of viscosity of lubricants when the temperature increases. To this aim, complementary low molecular weight polymers (for engine targeted application) that can reversibly associate with temperature through the diol-boronic ester exchange reaction have been designed and synthesized. The low molecular weights of the polymers and the dynamic behavior of the boronic ester bond decrease the high shear sensitivity of the system and so limits the shear-thinning behavior of the lubricant. The increase of polymeric function availability as the temperature rises induces polymer association. The reversibility of the thermo-associative association of polymers in non polar oil is seen over several cycles of warming-cooling with the increase of the relative viscosity of the solutions with increasing temperature. Part of the study was also dedicated to the improvement of polymers’ thermal stability in order to maintain the good lubricant properties of the thermo-associative formulations up to 150°C. Many polymers of different natures, sizes and topologies have been synthesized. The flow behavior of these polymers in both individual state in solution or in thermo-associative formulations was studied by rheology, thus enabling to determine the impact of these levers on the solutions properties as a function of temperature
Derouineau, Thibault. "Synthèse et étude de polymères thermo-associatifs pour le domaine des lubrifiants." Electronic Thesis or Diss., Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLET018.
Controlling the viscosity of engine lubricants is a key issue to reduce the fuel consumption of engines. A new approach based on the use of thermo-associative polymers has been developed in order to compensate the natural loss of viscosity of lubricants when the temperature increases. To this aim, complementary low molecular weight polymers (for engine targeted application) that can reversibly associate with temperature through the diol-boronic ester exchange reaction have been designed and synthesized. The low molecular weights of the polymers and the dynamic behavior of the boronic ester bond decrease the high shear sensitivity of the system and so limits the shear-thinning behavior of the lubricant. The increase of polymeric function availability as the temperature rises induces polymer association. The reversibility of the thermo-associative association of polymers in non polar oil is seen over several cycles of warming-cooling with the increase of the relative viscosity of the solutions with increasing temperature. Part of the study was also dedicated to the improvement of polymers’ thermal stability in order to maintain the good lubricant properties of the thermo-associative formulations up to 150°C. Many polymers of different natures, sizes and topologies have been synthesized. The flow behavior of these polymers in both individual state in solution or in thermo-associative formulations was studied by rheology, thus enabling to determine the impact of these levers on the solutions properties as a function of temperature
Charles, Antoine Henri Etienne. "Étude thermo-rhéologique de boues digérées : application à l’écoulement en conduite dans les procédés de méthanisation." Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Lille Douai, 2023. http://www.theses.fr/2023MTLD0008.
The society’s wastewater treatment needs are met by waste water treatment plants that produce sludges. In order to anticipate the increase in this requirement in the future, the sludge treatment processes must achieve a certain level of efficiency in terms of sludge treatment and recovery. The anaerobic digestion process significantly reduces the volume of sludge generated and can the be used for agricultural and energy purposes, in the form of digestate, biogas, electricity or heat. It is nevertheless limited by ineffective control of the transport of digested sludge within it, due to a lack of knowledge of thermo-rheology, in terms of understanding and characterisation methods, and of the hydrodynamics involved in handling these very diverse sludges. This manifests itself operationally, downstream of the sizing and design phase, in inefficient pumping, matrix heterogeneity or component clogging.It is in this context of providing scientific elements, on the one hand of the therm-rheological characerisation of digested sludge and on the other hand of the demonstration of the hydrodynamics of these fluids in operation, that the research work carried out within the framework of this thesis falls within the scope of.Firstly, protocols dedicated to the specific characterisation of each non-Newtonian behaviour have been established. The application of these protocols, at the ITM Nord Europe – Energy Environment research centre and on the industrial partner’s Characterisation plateform, shows that the thermo-rheological characteristics of digested sludge are accurately modelled by a non-modified Herschel-Bulkley model. Yield stress and shear-thinning are significantly more important than the other thermo-rheological characteristics of thixotropy, viscoelasticity and thermo-dependence. The unanticipated physical phenomon of wall slip is observed in these digested sludges, leading to heterogeneous flow hydrodynamics under conditions of low inertia and loaw wall roughness.Secondly, an experimental set-up dedicated to studying the flow of such fluids in pipe is being set up, with a visualisation to determining their hydrodynamic behaviour. Using working fluids (Carbopol solutions), it was demonstrated that these fluids undergo a rheo-inertial transition (RIT) towards turbulence. This transition is characterised by the existence of a pre-transition regime, non-existent for a Newtonian fluid, within which the flow exibits an asymmetry, which is observed by direct visualisation. These visualisations, coupled with the measurement of pressure drops, also make it possible to quantify the intermittency of the RIT on the basis of the turbulent structures visualised. This makes it possible to control the movement of such fluids through knowledge of the stabilisation of their flows and the increase in the residence time of turbulent structures, due to the non-Newtonian characteristics without viscoelasticity.Thus, this thesis manuscipt summarises the scientific elements developed within the framework of this thesis to respond to the problems of the operational obstacles encountered. As these problems stem from a lack of fundamental knowledge of the thermo-rheology and hydrodynamics of the sludge that flows through it, the study focuses its research on these two areas in order to provide the fundamentals that will make it possible to improve the control of sludge transport within the anaerobic digestion process in wastewater treatment plants
Bailly, Laurence. "Etude du comportement de deux grades cyanates esters pour des applications structurales en matériaux composites en environnement tiède." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0064.
Composite materials made of cyanate ester resins and in particular phenolic triazine resins such as PT15 and PT30 are selected to replace structural metal parts in aircraft at operating temperatures between 200 and 300°C. The main advantages of these resins are their high glass transition temperature, above 300°C, and their low viscosity at 80°C make them suitable for Resin Transfert Molding (RTM) process. The main goals of this work are to understand the resins’ behavior during crosslinking and then to study their durability through thermo-oxidative aging at operating temperatures. Physico-chemical characterizations of PT15 and PT30 resins at their initial state showed a similar chemical composition and spatial configuration but a different molar mass distribution. Triazine rings have only been detected in PT30 only, indicating a “pre-cured” state. These differences have consequences on the crosslinking kinetics and promote an autocatalytic mechanism for PT30. After cure optimization, PT15 has a glass transition temperature 70°C lower than the one of PT30. Among different analysis techniques, the rheological study during crosslinking provided an understanding of the networks’ structuration dissimilarities between the two grades, highlighting the formation of an intermediate structure which relaxes at lower temperatures in PT15. This different networks’ organization is the key element to understand dissimilar thermal stabilities analyzed during thermo-oxidative aging
Hertgen, Solenn. "Comportement mécanique des roches et dynamique des lithosphères dans les zones de convergence." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1B070/document.
Convergence zones are key objects to the understanding of the lithosphere dynamics. They are the location correspond to places of intense deformation as evidenced by the concentration and magnitude of recorded earthquakes. On a larger scale of time and space, these deformations generally result in nappes stacking whose study offers access to the different structural levels involved in the mountain belt structuration. Precisely characterizing the structuring dynamics of these units as well as the parameters controlling this dynamic is a crucial step that would allow in particular a better quantification of lithospheric dynamics. The aim of this thesis is twofold: (1) clarifying the rheological behavior of rocks in the Pressure-Temperature (P-T) conditions of the eclogitic facies at the subduction interface and (2) characterizing and quantifying the influence of the overriding plate rheology, and more specifically, the role of its crustal part, on the spatio-temporal evolution of convergence zones. For this, I used a multi-disciplinary approach. First, I present a multi-scale analysis combining fieldwork and metamorphic petrology, which allowed me to study the deformation within High Pressure-Low Temperature (HP-LT) rocks at the subduction interface in the Mont-Emilius klippe (Western Alps, Italy). Then, I show the results of a quantitative study combining 3D and 2D thermo-mechanical modeling of convergence zones. The entire set of models allowed me to analyze different parameters influencing the rheological structure of the overriding plate, such as the initial geotherm, the thicknesses of the lithosphere and the crust, and the nature of the involved materials. All the performed models are constrained/compared by/with data from natural examples. The results of the study on deformed rocks within the subduction interface highlight the possible brittle behavior of rocks at pressure and temperature conditions on the order of 2.15-2.40 GPa and 500-550 °C, i.e., in the eclogitic facies. The recording of such a deformation mode is of paramount importance because it challenges the paradigm of subduction interface caracterized by ductile behavior without resistance. The results obtained with the numerical models show that the rheology of the overriding plate, as well as that of only its crustal part, has a first-order influence on the overall dynamics of the convergence zones by modifying the mode of subduction, trench kinematics, the mode of exhumation during collision, the timing for slab break-off and back-arc basin formation, the location and intensity of deformation within the overriding plate. The combination of petrology and numerical modeling methods allowed me to obtain a quantified analysis of the influence of the rheology of the lithospheres involved in convergence zones on the dynamics of these zones. This thesis presents new constraints for our understanding of the mechanical response of the lithosphere at different spatial scales as a function of its rheological structure. The new data presented here reveal the major impact of the lithosphere rheology in convergence zones. This parameter leads us to reconsider our current view of the convergence zones
Diouf-Lewis, Audrey. "Elaboration et évaluation d'additifs verts pour polymères et composites respectueux de l'environnement." Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC028/document.
This thesis work falls within the identified context of the need to develop new polymers that are more environmentally friendly. We are convinced that the development of these "green" materials requires the use of "green" additives during formulation. To develop environmentally friendly additives capable of stabilizing the polymer, with respect to the life cycle, and paying special attention to biomass valorization, three approaches have been studied. The first is an innovative way of using a mixture of polyphenols from winery by-products and tea industry. The second way is the valorisation of a molecule from the major by-product of the wheat industry. The third is a recent route of innovation, which proposes the use of layered double hydroxides nanocomposites (LDH) functionalized with bio based stabilizers. The evaluation of their stabilizing properties is carried out in polyolefins, against thermo- and photo-oxidation processes. The very promising results of the project highlight the strong potential of bio based molecules and composites to maintain polymers properties under conditions of use
Rajaonarison, Tahiry Andriantsoa. "A Geodynamic Investigation of Continental Rifting and Mantle Rheology: Madagascar and East African Rift case studies." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/102410.
Doctor of Philosophy
Continental rifting is an important geodynamic process during which the Earth's outer-most rigid shell undergoes continuous stretching resulting in continental break-up and theformation of new oceanic basins. The East African Rift System, which has two continentalsegments comprising largely of the East African Rift (EAR) to the West and the easternmostsegment Madagascar, is the largest narrow rift on Earth. However, the driving mechanismsof continental rifting remain poorly understood due to a lack of numerical infrastructure tosimulate rifting, the lack of knowledge of the underlying mantle dynamics, and poor knowl-edge of mantle rheology. Here, we use state-of-art computational modeling of the upper660 km of the Earth to: 1) provide a better understanding of mantle flow patterns and themantle rheology beneath Madagascar, 2) to elucidate the main driving forces of observedpresent-day∼E-W opening in the EAR, and 3) to investigate the role of multiple plumesor a superplume in driving surface deformation in the EAR. In chapter 1, we simulate EdgeDriven convection (EDC), constrained by a lithospheric thickness model beneath Madagas-car. The mantle flow associated with the EDC is used to calculate induced olivine aggregates'Lattice Preferred Orientation (LPO), known as seismic anisotropy. The predicted LPO isthen used to calculate synthetic seismic anisotropy, which were compared with observationsacross the island. Through a series of comparisons, we found that asthenospheric flow result-ing from undulations in lithospheric thickness variations is the dominant source of the seismicanisotropy, but fossilized structures from an ancient shear zone may play a role in southern Madagascar. Our results suggest that the rheological conditions needed for the formationof seismic anisotropy, dislocation creep, dominates the upper asthenosphere beneath Mada-gascar and likely other continental regions. In chapter 2, we use a 3D numerical model ofthe lithosphere-asthenosphere system to simulate instantaneous lithospheric deformation inthe EAR and surroundings. We test the hypothesis that the∼E-W extension of the EAR isdriven by large scale forces arising from topography and internal density gradients, known aslithospheric buoyancy forces. We calculate surface deformation solely driven by lithosphericbuoyancy forces and compare them with surface velocity observations. The lithosphericbuoyancy forces are implemented by imposing observed topography at the model surfaceand lateral density variations in the crust and mantle down to a compensation depth of 100km. Our results indicate that the large-scale∼E-W extension across East Africa is driven bylithospheric buoyancy forces, but not along-rift surface motions in deforming zones. In chap-ter 3, we test the hypothesis that the anomalous northward rift-parallel deformation observedin the deforming zones of the EAR is driven by viscous coupling between the lithosphereand deep upwelling mantle material, known as a superplume, flowing northward. We testtwo end-member plume models including a multiple plumes model simulated using high res-olution shear wave tomography-derived thermal anomaly and a superplume model (Africansuperplume) simulated by imposing a northward mantle-wind on the multiple plumes model.Our results suggest that the horizontal tractions from northward mantle flow associated withthe African Superplume is needed to explain observations of rift-parallel surface motions indeforming zones from GNSS/GPS data and northward oriented seismic anisotropy beneaththe EAR. Overall, this work yields a better understanding of the geodynamics of Africa.
Vasile, Virginia. "Experimental study of the thermal and rheological behaviour of paraffin-in-water emulsions used as a secondary refrigerants." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI056/document.
A phase change material emulsion (PCME) is a fluid consisting of an emulsion of a phase change material (PCM), such as paraffin, dispersed in a carrier fluid (contiunuous phase), often water of an aqueous solution of surfactant. PCMEs can be considered as potential high performance thermal fluids (used as secondary refrigerants or as heat transport fluids) owing to their latent heat involved in the fusion of cristalisation of the PCM. This thesis reports experimental results concerning the thermo-rheological behavior of different versions of a PCME (30%wt. paraffin concentration in various acqueous solutions of surfactant) over the temperature range [0 – 20 °C]. The thermophysical properties of the PCMEs were determined. Then, an experimental study of forced convection heat transfer during laminar flow was carried out. The convective heat transfer coefficient of the PCMEs during cooling was determined in an experimental configuration mocking up applications in plate heat exchangers. The configuration mainly consists of two 1 m long rectangular channels (80 x 6 mm2). Correlations were developped for the prediction of the (local and overall) heat transfers coefficients, based on the Nussel, Reynolds and Prandtl numbers. A specific test bench was also used to analyse the rheological behaviour of the PCMEs. Tests were carried out using a viscometer at different temperatures. The stability of the emulsion was examined under various thermo-mechanical loads. Experiments revealed a pseudoplastic behavior for all tested versions of the PCME. All these results show that PCMEs are an attractive candidate for their applications in the field of air conditioning
Diouf-Lewis, Audrey. "Elaboration et évaluation d'additifs verts pour polymères et composites respectueux de l'environnement." Electronic Thesis or Diss., Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC028.
This thesis work falls within the identified context of the need to develop new polymers that are more environmentally friendly. We are convinced that the development of these "green" materials requires the use of "green" additives during formulation. To develop environmentally friendly additives capable of stabilizing the polymer, with respect to the life cycle, and paying special attention to biomass valorization, three approaches have been studied. The first is an innovative way of using a mixture of polyphenols from winery by-products and tea industry. The second way is the valorisation of a molecule from the major by-product of the wheat industry. The third is a recent route of innovation, which proposes the use of layered double hydroxides nanocomposites (LDH) functionalized with bio based stabilizers. The evaluation of their stabilizing properties is carried out in polyolefins, against thermo- and photo-oxidation processes. The very promising results of the project highlight the strong potential of bio based molecules and composites to maintain polymers properties under conditions of use
Tajul, Islam Mollah Mohammad. "Experimental study on Temperature regulating bi-component fibres containing paraffin wax in the core." Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19749.
Program: Magisterutbildning i textilteknologi
Jaber, Ahmad. "Interfacial Viscoelastic moduli of bare, surfactant-laden and nanoparticle-laden interfaces oscillating in a weak gel." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0104.
We present a study implementing the oscillating drop method to probe the oil/water interface, modifiable by surfactants or nanoparticles, while surrounded by a continuous phase of controllable rheology. The key question posed in this work concerns the effect of the rheological properties of the continuous phase on the measurements of interfacial viscoelastic moduli extracted from the compression/expansion of an oscillating drop. With this in mind, the continuous phase consists of a thermo-reversible hydrogel K-carrageenan, selected for its interfacial inactivity but also for its hysteresis after the sol/gel transition which allows to have a gel or liquid at the same temperature according to the thermal history.In the case of a pure oil/water interface and under conditions where the KC solution is liquid, the elastic modulus of the interface remains weak. When the KC solution becomes a gel, even if it is weak to the point that the solution flows under its own weight, we witness the appearance of an elastic signature in interfacial viscoelastic measures attesting to the contribution of the rheology of the continuous phase being not negligible.The presence of a surfactant at the oil/water interface, generating an interfacial elastic modulus that increases with the concentration of surfactant in the case of a liquid surrounding medium. In the presence of a weak gel, the interfacial modulus decreases by despite that the modulus of the KC gel increases, this is attributed to a pseudo-localization of deformation at the interface. This phenomenon disappears in the case of an interface laden with solid nanoparticles (Pickering effect).All of this work reveals the importance of deconvoluting interfacial and volume contributions in an interfacial viscoelasticity test of the pendant drop
Zhao, Feng D. "The processing of thermotropic liquid crystalline polymers within a polypropylene matrix for the production of oriented thermo-reversible blends." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338073.
Болонний, В. Т. "Підвищення ефективності функціонування нафтопроводів шляхом урахування реологічних особливостей нафт Прикарпаття". Thesis, Івано-Франківський національний технічний університет нафти і газу, 2006. http://elar.nung.edu.ua/handle/123456789/4097.
В первом разделе приведен анализ существующих работ по вопросам перекачивания высоковязких нефтей и нефтепродуктов с подогревом, выявлены нерешенные вопросы и сформулированы задачи исследований. Показано, что актуальность проблемы повышения эффективности транспортирования высоковязких нефтей с подогревом по трубопроводам не исчерпана и предоставляет широкие возможности для научной деятельности. Второй раздел содержит методику проведения и анализ результатов экспериментальных исследований реологических свойств высоковязкой высокозасты-вающей долинской нефти. Исследования проводились на структурном ротационном вискозиметре «Реотест-2». На основании опытов построены графические зависимости динамического напряжения сдвига от градиента скорости для значений градиентов от 0 до 1312 1/с в диапазоне температур от 65 до 5 °С. Доказано, что долинская нефть при температурах, ниже 50 °С, проявляет свойства вязко-пластичной жидкости и ее движение может быть описано уравнением Шведова-Бингама. На основании экспериментов определены значения коэффициентов реологической модели - граничное динамическое напряжение сдвига и пластическая вязкость нефти. Получены полиномиальные зависимости этих коэффициентов от температуры. Третий раздел посвящен созданию математической модели установившегося теплогидравлического режима работы неизотермического нефтепровода при перекачивании ньютоновских и неньютоновских жидкостей. В качестве исходных выражений использована система дифференциальных уравнений в виде, предложенным М.В. Лурье. Система дополнена слагаемыми, учитывающими тепло трения потока и скрытую теплоту кристаллизации парафина. Для коэффициента гидравлического сопротивления предложена универсальная модель Лейбензона, в которой число Рейнольдса и коэффициенты режима в отличие от существующих методик являются переменными для каждого сечения трубопровода. Для определения переменных коэффициентов режима предложен адаптивный метод, основанный на использования формулы Колбрука. Четвертый раздел посвящен разработке методов и компьютерных программ для теплогидравлических расчетов неизотермических нефтепроводов при перекачивании ньютоновских жидкостей. Пятый раздел содержит результаты разработки методов и компьютерных программ для теплогидравлических расчетов неизотермических нефтепроводов при перекачивании неньютоновских жидкостей. Предложена также методика теплогидравлического расчета нефтепровода при последовательной перекачке жидкостей, существенно отличающихся реологическими свойствами. Апробация методик произведена путем выполнения технологических расчетов и сравнения полученных результатов с фактическими параметрами работы нефтепровода Долина-Дрогобыч. Максимальное отклонение результатов не превышает ± 8 %.
The thesis is devoted to the increase of oil pipeline effective operation by the development of methods to forecast thermo-hydraulic parameters of the pipelines' work taking into account the rheological peculiarities of high-viscosity oils in the Precarpathia. Serial experimental research of rheological characteristics of highly solidifying oil from Dolyna deposit has been conducted in a wide temperature span. It has been acknowledged the selection of rheological model of Dolyna oil in different temperature spans. An analytical method has been applied to determine, according to the research data, the coefficient values of the rheological model of Shwedow-Bingam. The empirical models of the dependence of boundary dynamic stress fault and rigidity on temperature have been offered as well. Besides, there has been developed a universal mathematical model for the hydraulic resistance coefficient in the anisothermic pipeline with the help of which we can receive appropriate results in all friction zones of turbulent condition and get the possibility to calculate the change of liquid flow regime coefficients in every pipeline cross-section. Moreover, the author offers a mathematical model of the fixed anisothermic liquid flow in a pipeline, which includes the influence of friction heat flow, hidden heat of paraffin crystallization, coefficients change of the liquid flow regime and oil rheological peculiarities. To make thermo-hydraulic calculations of anisothermic pipeline during the process of oil pumping there have been created a pack of methods and software which can be characterized by the Newtonian and non-Newtonian properties. It has been offered the method of thermo-hydraulic calculation of anisothermic pipeline during batching of oils with the essential difference of rheological properties. The developments have been approved by technological calculations and comparison of their results with the real operation regimes of Dolyna-Drohobych pipeline.
"Thermo-Mechanical Analysis of Temporary Bonding Systems for Flexible Microelectronics Fabrication Applications." Doctoral diss., 2011. http://hdl.handle.net/2286/R.I.9038.
Dissertation/Thesis
Ph.D. Chemical Engineering 2011