Добірка наукової літератури з теми "Thermo-rheology"
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Статті в журналах з теми "Thermo-rheology":
1
Ahuja, Amit, and Chaiwut Gamonpilas. "Rheology of thermo-gelling capillary suspensions." Colloid and Polymer Science 299, no. 1 (November 11, 2020): 165–76. http://dx.doi.org/10.1007/s00396-020-04772-8.
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Wang, Chong Ge, Zhao Qing Song, Wei Zhong Chen, Quan Sheng Liu, and Chien Hsin Yang. "Study of Thermo-Rheology Characters of Rock under the Uni-Axial Compression." Key Engineering Materials 261-263 (April 2004): 639–44. http://dx.doi.org/10.4028/www.scientific.net/kem.261-263.639.
Анотація:
This paper introduces temperature effect to rock model. It sets up a thermo-visco-elastic-plastic rock model. Based on the rock model which consists of spring, dashpot and plastic elements under the condition of un-axial compression, the behaviors of the thermo-visco-elastic-plastic in rock are discussed, and the equations of the constitutive, creep, unload and relaxation have been obtained. This model can reflect the rock or rock mass average thermo-rheology character. Meanwhile, this study gives a explanation of the significances of this kind of model in the practical use.
3
Brenner, Tom, Taco Nicolai, and Ragnar Johannsson. "Rheology of thermo-reversible fish protein isolate gels." Food Research International 42, no. 8 (October 2009): 915–24. http://dx.doi.org/10.1016/j.foodres.2009.04.020.
4
Niang, Pape Momar, Zhiwei Huang, Virginie Dulong, Zied Souguir, Didier Le Cerf, and Luc Picton. "Thermo-controlled rheology of electro-assembled polyanionic polysaccharide (alginate) and polycationic thermo-sensitive polymers." Carbohydrate Polymers 139 (March 2016): 67–74. http://dx.doi.org/10.1016/j.carbpol.2015.12.022.
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Li, Boyu, Joey Kim, and Julie Kornfield. "A Molecular Picture for the Thermo-Reversibility of Gels Formed by Isophthalic Acid-Ended Telechelic Polymers." MRS Proceedings 1794 (2015): 9–14. http://dx.doi.org/10.1557/opl.2015.638.
Анотація:
ABSTRACTWe demonstrate that isophthalic acid-ended telechelic poly(1,5-cyclooctadiene)s (A-PCODs) form thermo-reversible gels in non-polar solvent with a unique molecular mechanism for their thermo-reversibility. Like other associative telechelic polymers, A-PCODs form “flower-like” micelles at low concentration and form gels through bridging at higher concentration which exhibit linear viscoelasticity. However, unlike the widely studied hydrophobically end-capped PEOs, A-PCODs show clear thermo-reversibility in viscosity and dynamic modulus around 30 °C due to the hydrogen-bonding end groups. In addition, they differ from other reported thermo-reversible gelators (eg. Pluronics, PNIPAm containing block copolymers, etc.): neither the end group nor the backbone in the present system has a critical solution temperature within the measured temperature range (0 °C to 60 °C), indicating that the present system has a unique mechanism for its thermo-reversibility. To obtain a molecular picture of the mechanism, rheology and small angle neutron scattering (SANS) studies were implemented. Topological changes above the transition temperature (30 °C) were observed in both oscillatory rheology and SANS. SANS reveals that the size of clusters, which are formed by interacting micelles, depends highly on temperature (T) but independent of polymer concentration. These results cannot be explained by current theories on associative telechelic polymers which assume constant and large aggregation number of end groups at all temperatures and concentrations. We hypothesize that the temperature-sensitive sol-gel transition is due to a decrease in aggregation number for T above the critical temperature in our system, and this temperature-dependence of aggregation number is further determined by the chemical structure and hydrogen-bonding property of isophthalic acid ends.
6
Vargas Arenas, Xiomara Andrea, Natalia Afanasjeva, and Mario Álvarez Cifuentes. "Rheological model for sol-gel phase transition of thermo-aged heavy oil fractions." Ingeniería e Investigación 30, no. 1 (January 1, 2010): 28–34. http://dx.doi.org/10.15446/ing.investig.v30n1.15203.
Анотація:
A power-law rheological model is proposed in this paper: G’’(ω) ~ ωn and G’(ω) ~ ωn. It represents the increased connectivity between thermo-aged asphalt molecules in a rheo-reactor as one of the applications of systematic rheology. The results confirmed a sol-gel phase transition tendency for aged asphalt in the experimental frequency window at temperatures below 40°C. Such pattern could have been related to the structuring effect arising from the thermo-oxidative asphalt aging process during continuous agitation which has been suitably described by the micellar model of asphalt.
7
Wu, Yufeng, Dingwei Zhu, Zanru Guo, and Yujun Feng. "Rheology and phase behavior of thermo-reversible pentablock terpolymer hydrogel." Journal of Polymer Science Part B: Polymer Physics 51, no. 18 (July 10, 2013): 1335–42. http://dx.doi.org/10.1002/polb.23343.
8
Nedoma, J. "On a coupled Stefan-like problem in thermo-visco-plastic rheology." Journal of Computational and Applied Mathematics 84, no. 1 (October 1997): 45–80. http://dx.doi.org/10.1016/s0377-0427(97)00111-8.
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VARGAS, X., N. AFANASJEVA, M. ALVAREZ, P. MARCHAL, and L. CHOPLIN. "Asphalt rheology evolution through thermo-oxidation (aging) in a rheo-reactor." Fuel 87, no. 13-14 (October 2008): 3018–23. http://dx.doi.org/10.1016/j.fuel.2008.04.026.
10
Kumar, Rahul, Mohammad Sikandar Azam, Subrata Kumar Ghosh, and Hasim Khan. "Thermo-elastohydrodynamic lubrication simulation of the Rayleigh step bearing using the progressive mesh densification method." SIMULATION 95, no. 5 (August 1, 2018): 395–410. http://dx.doi.org/10.1177/0037549718788727.
Анотація:
The paper deals with the numerical simulation of thermo-elastohydrodynamic lubrication (Thermo-EHL) condition in the Rayleigh step bearing. Thermo-EHL involves rheology of the lubricant and deformation of the structure simultaneously under the influence of pressure and temperature, which makes this regime of lubrication more complicated. It is difficult to obtain a converged and accurate solution with ease under this condition. The effect of computational mesh density plays a significant role in obtaining a converged solution rapidly. In this paper, the progressive mesh densification (PMD) method has been applied to solve the Thermo-EHL condition numerically. To find out the best possible scheme of PMD for obtaining a converged solution quickly, the results of PMD and fixed mesh density (FMD) have been compared. Based on the comparison, it has been observed that Scheme 3 of PMD takes around 30% fewer iterations compared with FMD under both elastohydrodynamic lubrication (EHL) and Thermo-EHL conditions. Adopting Scheme 3 of PMD, the effect of temperature on the load capacity, coefficient of friction, no-pressure zone, and pressure distribution in the Rayleigh step bearing has been studied. Reductions in pressure, no-pressure zone, frictional coefficient, and load capacity are observed under the Thermo-EHL condition compared to the EHL condition.
Дисертації з теми "Thermo-rheology":
1
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.
Анотація:
Phenylethynyl terminated imides (PETI) are high temperature, high performance matrix resins that can be processed into composites by various methods including resin transfer molding (RTM) arid vacuum assisted resin transfer molding (VARTM). PETI resins have experienced extremely rapid development in recent years, with major emphasis placed on engineering applications that take advantage of their high cured TgS,high thermooxidative stability, high strength to weight ratio, outstanding mechanical properties, and compatibility with RTM and VARTM processing. In recent years the addition of nanoparticles to resin systems has been shown to further enhance the mechanical properties and thermooxidative stability. In this study, we incorporated nanoporous aluminosilicate materials, otherwise known as zeolites, into PETI resin GRC-A, and investigated the effect the zeolites have on the viscosity, cure kinetics, thermooxidative stability and other thermomechanical properties of GRC-A. Rheological and differential scanning calorimetry studies conducted on the GRC-Alzeolite mixtures showed that zeolite L acts like a filler and retards the curing of the phenylethynyl end-groups, while zeolite Y catalyzes the curing process. Additionally, cure kinetic studies via melt rheology and DSC confirmed that the activation energies for GRC-A/zeolite Y mixtures as lower than for neat GRC-A and GRC-A/zeolite L mixtures, further supporting zeolite L acts as a filler while zeolite Y serves as a catalyst during the cure process. While the cured Tgs, from the DMA and TMA studies showed that in spite of the catalytic properties of zeolite Y; it did not afford additional properties over GRC-A and zeolite L mixtures. However, the catalytic properties of zeolite Y allows PETI resins to be cured at a lower temperatures, which could lead to lower energy costs in the production of composite parts from PETI resins.
2
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.
Анотація:
Le contrôle de la viscosité des lubrifiants moteur est un enjeu clé dans la réduction de la consommation en carburant des moteurs thermiques. Une nouvelle approche basée sur l’utilisation de polymères thermo-associatifs a été développée pour diminuer la perte de viscosité naturelle des lubrifiants avec la température. Pour ce faire, des polymères complémentaires de faibles masses molaires (pour l’application moteur visée) qui peuvent s’associer réversiblement via la réaction d’échange diol-ester boronique lorsque la température augmente ont été conçus et synthétisés. Les faibles masses molaires des polymères et le caractère dynamique de la liaison ester boronique permettent de diminuer la sensibilité de ces systèmes aux forts cisaillements présents dans le moteur, en limitant notamment la rhéofluidification de ces lubrifiants. L’association des polymères est provoquée par l’augmentation d’accessibilité des fonctions portées par les polymères avec la température. L’association réversible des polymères thermo-associatifs a été mise en évidence dans les huiles apolaires par l’augmentation de la viscosité relative des solutions avec la température sur plusieurs cycles de chauffage-refroidissement. Une partie de l’étude a été consacrée à l’amélioration de la stabilité thermique des polymères dans le but de maintenir les bonnes propriétés lubrifiantes des formulations jusqu’à 150°C. Un grand nombre de polymères de natures, de tailles et d’architectures différentes ont été synthétisés. L’étude rhéologique en écoulement de ces polymères seuls et en formulations thermo-associatives a permis de mettre en évidence l’importance de ces différents leviers pour faire varier et contrôler les propriétés des solutions en fonction de la températureControlling 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
3
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.
Анотація:
Le contrôle de la viscosité des lubrifiants moteur est un enjeu clé dans la réduction de la consommation en carburant des moteurs thermiques. Une nouvelle approche basée sur l’utilisation de polymères thermo-associatifs a été développée pour diminuer la perte de viscosité naturelle des lubrifiants avec la température. Pour ce faire, des polymères complémentaires de faibles masses molaires (pour l’application moteur visée) qui peuvent s’associer réversiblement via la réaction d’échange diol-ester boronique lorsque la température augmente ont été conçus et synthétisés. Les faibles masses molaires des polymères et le caractère dynamique de la liaison ester boronique permettent de diminuer la sensibilité de ces systèmes aux forts cisaillements présents dans le moteur, en limitant notamment la rhéofluidification de ces lubrifiants. L’association des polymères est provoquée par l’augmentation d’accessibilité des fonctions portées par les polymères avec la température. L’association réversible des polymères thermo-associatifs a été mise en évidence dans les huiles apolaires par l’augmentation de la viscosité relative des solutions avec la température sur plusieurs cycles de chauffage-refroidissement. Une partie de l’étude a été consacrée à l’amélioration de la stabilité thermique des polymères dans le but de maintenir les bonnes propriétés lubrifiantes des formulations jusqu’à 150°C. Un grand nombre de polymères de natures, de tailles et d’architectures différentes ont été synthétisés. L’étude rhéologique en écoulement de ces polymères seuls et en formulations thermo-associatives a permis de mettre en évidence l’importance de ces différents leviers pour faire varier et contrôler les propriétés des solutions en fonction de la températureControlling 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
4
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.
Анотація:
Le besoin en traitement des eaux usées par la société est assurée en usine d’épuration par des traitements menant à la production de boues. Afin d’anticiper l’augmentation de ce besoin à l’avenir, les filières de traitement de ces boues doivent atteindre une certaine efficacité, en termes de traitement et de valorisation des boues. Parmi ces filières, le procédé de méthanisation permet de réduire significativement le volume des boues générées et permet par la suite une valorisation agronomique et énergétique, sous forme de digestat, de biogaz, d’électricité ou de chaleur. Il est néanmoins limité par un contrôle inefficace du transport des boues digérées en son sein, du fait de la méconnaissance de la thermo-rhéologie, en termes de connaissances et de méthodes de caractérisation et en termes d’hydrodynamique en conduite de ces boues très diverses. Cela se manifeste opérationnellement, en aval de la phase de dimensionnement et de conception, lors de l’opération par des pompages inefficaces, des hétérogénéités de la matrice ou des colmatages de composants.C’est dans cette optique d’apport des éléments scientifiques, de la caractérisation thermo-rhéologique des boues digérées d’une part et de la mise en évidence de l’hydrodynamique en conduite de ces fluides d’autre part, que le travail de recherche mené dans le cadre de cette thèse s’inscrit.Premièrement, des protocoles dédiés à caractériser spécifiquement chaque comportement non-newtonien sont établis pour cela. L’application de ces protocoles, au centre de recherche Energie Environnement de l’IMT Nord Europe et sur la plateforme Caractérisation du partenaire industriel, montre que les caractéristiques thermo-rhéologiques des boues digérées sont fidèlement modélisées par un modèle d’Herschel-Bulkley non modifié. En effet, la contrainte seuil et la rhéofluidification sont significativement pré-pondérantes devant les autres caractéristiques thermo-rhéologiques de thixotropie, de visco-élasticité et de thermo-dépendance. Le phénomène physique non anticipé de glissement aux parois est observé sur ces boues digérées, menant à une hydrodynamique hétérogène de l’écoulement en conduite de faible inertie et de faible rugosité des parois.Deuxièmement, un dispositif expérimental dédié à l’étude de l’écoulement en conduite de tels fluides est mis en place en vue de déterminer leurs comportements hydrodynamiques. Il permet de démontrer, à l’aide de fluides de travail (solution s de Carbopol), que ces fluides suivent une transition rhéo-inertielles (RIT) vers la turbulence. Cette transition se distingue par l’existence d’un régime de pré-transition, inexistant pour un fluide newtonien, au sein duquel l’écoulement présente une asymétrie, qui est observée par visualisation directe. Ces visualisations, couplées à la mesure des pertes de charges, permettent de quantifier l’intermittence de la RIT à partir des structures turbulents visualisées. Cela permet de contrôler le mouvement de tels fluides par la connaissance de la stabilisation de leurs écoulements et de l’augmentation du temps de séjour des structures turbulentes, du fait des caractéristiques non-newtoniennes (sans visco-élasticité).Ainsi, ce manuscrit synthétise les éléments scientifiques développés dans le cadre de cette thèse pour répondre aux problématiques opérationnelles rencontrées. Les verrous découlant du mande de connaissances fondamentales de la thermo-rhéologie et de l’hydrodynamique des boues qui y circule, l’étude axe sa recherche sur ces deux domaines pour apporter les fondamentaux qui pourront permettre l’amélioration de la maîtrise du transport des boues au sein du procédé de méthanisation en usine d’épurationThe 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
5
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.
Анотація:
Les matériaux composites constitués de résines cyanates esters et plus particulièrement les résines phénoliques triazines PT15 et PT30 ont été sélectionnés pour remplacer des pièces structurales métalliques aéronautiques sollicitées à des températures de 200 à 300°C. Ces résines présentent à la fois une température de transition vitreuse élevée supérieure à 300°C et une faible viscosité pour une température de mise en œuvre à 80°C adaptée au procédé Resin Transfert Molding (RTM). Les objectifs de cette thèse sont d’une part de comprendre le comportement de ces résines durant leur mise en œuvre et leur polymérisation et d’autre part d’étudier la durabilité de ces résines à partir d’études de vieillissement thermo-oxydatif à des températures proches des températures d’utilisation. La caractérisation physico-chimique des résines PT15 et PT30 à l’état de réception a d’abord montré que ces deux grades sont constitués d’oligomères de même composition chimique, de même configuration spatiale mais de distributions de masses molaires différentes. La présence de cycles triazines dans la résine PT30 indique un état de « pré-réticulation » qui n’est pas décelable pour la résine PT15. Ces différences vont avoir une incidence sur la cinétique de la réaction de réticulation des deux résines et vont favoriser un mécanisme autocatalytique pour le grade PT30. Après optimisation d’un cycle de cuisson, ces deux grades présentent une différence de température de transition vitreuse de 70°C. Parmi les différentes techniques d’analyse expérimentées, ce sont les études rhéologiques au cours de la réticulation qui vont permettre de comprendre les différences de structuration des réseaux et de mettre en avant la formation d’un réseau intermédiaire qui relaxe à plus basse température pour la PT15. Cette différence d’organisation est l’élément clé qui permet de comprendre les différences de stabilités thermiques évaluées lors de vieillissement thermo-oxydatifComposite 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
6
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.
Анотація:
Les zones de convergence sont des objets clés à la compréhension de la dynamique de la lithosphère. Elles sont le siège de déformations majeures comme en témoignent la concentration et l’intensité des séismes qui leur sont associées. A plus grande échelle de temps et d'espace, ces déformations résultent généralement en un empilement d’unités dont l’étude offre l'accès aux différents niveaux structuraux mis en jeu dans l'organisation de la chaîne de montagnes. Caractériser précisément la dynamique de structuration de ces unités ainsi que les paramètres contrôlant cette dynamique constitue une étape cruciale permettant d’aller plus loin, notamment quantitativement, dans notre connaissance de la dynamique lithosphérique. Cette thèse a comme double objectif (1) de préciser le comportement rhéologique des roches aux conditions Pressions-Température P-T du faciès éclogitique au sein de l' interface de subduction et (2) de caractériser et quantifier l' influence de la rhéologie de la plaque supérieure, et plus spécifiquement, le rôle de sa partie crustale, sur l'évolution spatio-temporelle des zones de convergence. Pour cela, une approche multi-disciplinaire a été utilisée. Dans un premier temps, je présente une analyse multi-échelle couplant travail de terrain et de pétrologie métamorphique qui a permis d'étudier la déformation au sein de roches HP-BT à l' interface de subduction au niveau de la klippe du Mont-Emilius (Alpes occidentales, Italie). Je détaille ensuite une étude quantitative alliant modélisation numérique thermo-mécanique 3D et 2D de zones de convergence. L'ensemble des modèles a permis d'analyser de nombreux paramètres influençant la structure rhéologique de la plaque supérieure tels que le géotherme initial, l'épaisseur de la lithosphère et de la croûte et la nature des matériaux impliqués. L'ensemble des modèles réalisés sont contraints/confrontés par/aux des données issues d'exemples naturels. Les résultats de l'étude sur des roches déformées au sein de l’interface de subduction mettent en évidence le possible comportement cassant des roches à des conditions de pression et température de l'ordre de 2.15-2.40 GPa, 500-550 °C, i.e., dans le faciès éclogitique. L’enregistrement d’un tel mode de déformation est d'une importance capitale car il remet en question le paradigme d’un comportement ductile sans résistance au niveau de l’ interface de subduction. Les résultats obtenus via les modèles numériques montrent par ailleurs que la rhéologie de la plaque supérieure, ainsi que celle de sa seule partie crustale, a une influence de premier ordre sur la dynamique globale des zones de convergence en modifiant notamment le mode de subduction, la cinématique de la fosse, le mode d'exhumation lors d'une collision, le timing de la déchirure du slab et de la formation de bassins d'arrière-arc, la répartition et l'intensité de la déformation au sein de la plaque supérieure. La combinaison des méthodes de pétrologie et de modélisation numérique a permis d'obtenir une analyse quantifiée de l' influence de la rhéologie des lithosphères impliquées dans les zones de convergence sur la dynamique de ces zones. Cette thèse présente ainsi de nouvelles contraintes à notre compréhension de la réponse mécanique de la lithosphère, en fonction de sa structuration rhéologique et de sa place au sein des zones de convergence à petite et grande échelle. Les nouvelles données présentées révèlent l' impact majeur de la rhéologie de la lithosphère dans les zones de convergence. Ce paramètre amène ainsi à reconsidérer notre vision actuelle des zones de convergenceConvergence 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
7
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.
Анотація:
Ce travail de thèse s’inscrit dans le contexte identifié de la nécessité de développer de nouveaux polymères plus respectueux de l’environnement. Nous sommes convaincus que l’essor de ces matériaux « verts » exige d’utiliser des additifs « verts » lors de la formulation. Dans le but d’élaborer des additifs respectueux de l’environnement capables d’assurer la stabilisation du polymère au regard du cycle de vie, et en attachant une attention particulière à la valorisation de la biomasse, trois approches ont été étudiées. La première est une voie innovante qui consiste à utiliser un mélange de polyphénols issus des sous-produits de l’industrie vinicole, et de l’industrie du thé. La seconde voie est la valorisation d’une molécule issue du sous-produit majeur de l’industrie du blé. La troisième est une voie d’innovation récente, qui propose l’utilisation de nanocomposites hydroxydes doubles lamellaires (HDL) fonctionnalisés avec des stabilisants biosourcés. L’évaluation de leurs propriétés stabilisantes, est réalisée au regard des processus de thermo- et photo-oxydation, dans les polyoléfines. Les résultats très prometteurs de ce projet mettent en évidence le fort potentiel des molécules et composites d’origine biosourcée à maintenir les propriétés des polymères en conditions d’usagesThis 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
8
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.
Анотація:
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.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.
9
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.
Анотація:
Une émulsion à changement de phase (PCME: phase-change material emulsion) est un fluide consistant en une émulsion d'un matériau à changement de phase (PCM, phase change material), comme de la paraffine, dispersé dans un fluide porteur (phase continue), souvent de l'eau ou une solution acqueuse de surfactant. Les PCME peuvent être envisagés comme fluides à haute performance thermique (frigoporteurs ou caloporteurs) en raison de leur potentiel de transport de chaleur latente (cristallisation ou fusion du PCM). Cette thèse présente des résultats expérimentaux concernant le comportement thermo-rheologique des differentes versions de PCME (émulsions de paraffine dans différentes solutions acqueuses de surfactant, avec une concentration massique en paraffine égale à 30 %) sur une plage de température de 0 - 20 °C. Les propriétés thermophysiques des émulsions ont été déterminées. Ensuite, une étude expérimentale du transfert de chaleur par convection forcée laminaire a été effectuée. Le coefficient de transfert de chaleur convectif de l'émulsion pendant le refroidissement a été déterminé dans une configuration expérimentale proche de celle pouvant être rencontrée dans des échangeurs thermiques à plaques. La configuration se compose principalement de deux canaux rectangulaires (80 x 6 mm²) de longueurs égale à 1 m. Des corrélations utiles pour évaluer les coefficients d'échange thermique (locaux ou globaux) ont été établies entre les nombres de Nusselt, de Reynolds et de Prandtl. Un banc d'essais spécifique a également été utilisé pour analyser le comportement rhéologique des PCME. Des essais ont été effectués à l'aide d'un viscosimètre à différentes températures. La stabilité des émulsions a été examinée sous diverses charges thermomécaniques. Les expériences ont révélé un comportement rheofluidisant. L'ensemble de ces résultats montre que les PCME sont des candidats prometteurs pour les applications à la climatisationA 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
10
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.
Анотація:
Ce travail de thèse s’inscrit dans le contexte identifié de la nécessité de développer de nouveaux polymères plus respectueux de l’environnement. Nous sommes convaincus que l’essor de ces matériaux « verts » exige d’utiliser des additifs « verts » lors de la formulation. Dans le but d’élaborer des additifs respectueux de l’environnement capables d’assurer la stabilisation du polymère au regard du cycle de vie, et en attachant une attention particulière à la valorisation de la biomasse, trois approches ont été étudiées. La première est une voie innovante qui consiste à utiliser un mélange de polyphénols issus des sous-produits de l’industrie vinicole, et de l’industrie du thé. La seconde voie est la valorisation d’une molécule issue du sous-produit majeur de l’industrie du blé. La troisième est une voie d’innovation récente, qui propose l’utilisation de nanocomposites hydroxydes doubles lamellaires (HDL) fonctionnalisés avec des stabilisants biosourcés. L’évaluation de leurs propriétés stabilisantes, est réalisée au regard des processus de thermo- et photo-oxydation, dans les polyoléfines. Les résultats très prometteurs de ce projet mettent en évidence le fort potentiel des molécules et composites d’origine biosourcée à maintenir les propriétés des polymères en conditions d’usagesThis 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
Книги з теми "Thermo-rheology":
1
Ren, Shan. Thermo-hygro rheological behavior of materials used in the manufacture of wood-based composites. 1991.
2
Ren, Shan. Thermo-hygro rheological behavior of materials used in the manufacture of wood-based composites. 1991.
Частини книг з теми "Thermo-rheology":
1
Nedoma, Jiří. "On a Coupled Thermo-Hydro-Mechanical Problem Based on the Thermo-Visco-Plastic Rheology." In Computational Science and Its Applications — ICCSA 2003, 977–86. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/3-540-44839-x_103.
2
ŠTOK, B., and N. MOLE. "ON THE CALCULATION OF CYCLIC THERMO-PLASTIC STRESS PROBLEMS." In Theoretical and Applied Rheology, 830. Elsevier, 1992. http://dx.doi.org/10.1016/b978-0-444-89007-8.50375-0.
3
"7. Thermo-Mechanical Models of Convergent Orogenesis: Thermal and Rheologic Dependence of Crustal Deformation." In Rheology and Deformation of the Lithosphere at Continental Margins, 179–222. Columbia University Press, 2004. http://dx.doi.org/10.7312/karn12738-008.
Тези доповідей конференцій з теми "Thermo-rheology":
1
Aversa, C. "PET foaming: development of a new class of rheological additives for improved processability." In Italian Manufacturing Association Conference. Materials Research Forum LLC, 2023. http://dx.doi.org/10.21741/9781644902714-45.
Анотація:
Abstract. Polymer foaming is a process broadly used for manufacturing light weight packaging solutions. Polystyrene (PS) is the most widespread material for this application, as it combines easy processability, low cost and high performance of the resulting items. However, foamed PS is difficult to recycle and highly polluting for the oceans and aquatic environment. Polyethylene terephthalate (PET) is, instead, commonly recycled and R-PET is broadly used for several industrial applications. Yet, PET quickly loses viscosity during the foaming process, due to thermo-hydrolytic and oxidative degradation thus causing poor foaming. In this paper, an innovative combination of chain extenders, anti-oxidants and nucleating agents to modify PET rheology is studied. The additives were experimented both in off-line and in-line apparatus. The experimental results show PET rheology can be customized by appropriately modulating the content of the different additives, thus making PET suitable for foaming process of high-quality items.
2
Amin, Samiul. "Design of Smart Sustainable Emulsions for Cosmetic Applications." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/mgyn7615.
Анотація:
Development and design of sustainable cosmetic products is a key R&D priority across all the cosmetic and personal care companies. This is primarily due to the focus on addressing the strong consumer driver for cosmetic products that do not have a negative environmental footprint. This has led to the rapid development of new formulations where traditional ingredients such as synthetic surfactants, polymers, silicone oils etc are being replaced by more sustainable alternatives such as biosurfactants, biobased surfactants, biopolymers, natural oils. This replacement of traditional ingredients by more sustainable alternatives however is not trivial as re-building the performance of traditional ingredients is highly challenging. This is specifically true of oil-in-water and water-in-oil based emulsion systems which constitute a large majority of cosmetic products. The stability, texture/rheology/sensory has to be re-engineered in these sustainable formulations. This re-engineering of the formulations however does additionally present opportunities to build in new performance attributes and to additionally engineeer in smart or stimuli responsive behavior.This study will report on the formulation design of several novel sustainable emulsion systems-a thermo-responsive whey protein/chitosan oil-in-water emulsion system, a glycolipid/silica particle water-in-oil emulsion system, a thermo-responsive methylcellulose/chitosan hydrogel system incorporating an EGF (epidermal growth factor). The ability to tune the rheology and rheological response to external stimuli to deliver performance benefits will be illustrated.
3
Hammad, Khaled J. "The Heat Transfer Behavior of a Suddenly Expanding Viscoplastic Flow Field." In ASME 2016 Heat Transfer Summer Conference collocated with the ASME 2016 Fluids Engineering Division Summer Meeting and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ht2016-7365.
Анотація:
A parametric study is implemented to study the impact of inflow conditions, rheology, and thermo-physical properties on the flow and heat transfer behavior of suddenly expanding, recirculating, and non-recirculating, viscoplastic non-Newtonian flows. The governing mass and fully-elliptic partial differential equations of motion and energy along with the Bingham constitutive equations are numerically solved to provide accurate predictions of the velocity and temperature fields. The expansion ratio was fixed at 2. Inflow conditions, yield stress presence, and transitioning from a non-recirculating to a recirculating viscoplastic flow regime are found to have a strong influence on the overall heat transfer characteristics downstream the expansion plane.
4
CLOËZ, Liam. "Machinability of PLA obtained by injection molding under a dry milling process." In Material Forming. Materials Research Forum LLC, 2024. http://dx.doi.org/10.21741/9781644903131-208.
Анотація:
Abstract. This paper is part of a study focusing on the elaboration of accurate component with complex geometries using bio-sourced as an alternative to petrochemical polymer. The bio-sourced and biodegradable in this study is composed of a Poly Lactic Acid (PLA) matrix and hemp fibers. The final component is obtained by injection followed by a machining operation. the final component is obtained by injection followed by a machining finishing operation. Injection molding will be carried out to be compared with 3D printing on economic, environmental, production and workpiece quality criteria. This paper focuses only on the combination of two processes, injection molding followed by machining on poly (L-lactic acid) or PLLA which is biobased and biodegradable. After injecting the workpiece, thermo-physical characterization tests are realized on PLLA polymer. Rheology, thermal and mechanical tests are carried out in order to study thermomechanical behavior and to understand material flow phenomena at different temperatures and shear rates. The objective of this paper is to overcome the technical challenges of milling this material without any lubricant. In an upcoming project, various machining operations will be carried out such as turning to study continuous cutting, or milling to study discontinuous cutting on workpieces reinforced with bio-sourced fibers as hemp.
5
Punase, Abhishek, Antonio Pedro Oliveira, and Jonathan Wylde. "Green and Sustainable Asphaltene Dispersant with Cardanol Derivatives for Medium and Heavy Asphaltenic Oil Application." In SPE Eastern Regional Meeting. SPE, 2022. http://dx.doi.org/10.2118/211872-ms.
Анотація:
Abstract Phenolic resins are major class of polymeric compounds used for treating asphaltene instability related challenges. Such compounds often act like as artificial resins naturally present in crudes to prevent the aggregation of asphaltene molecules and therefore their tendency to deposit on solid surfaces. However, these phenolic resins are known to have toxicity and biodegradability issues. Aim of this work is to elucidate and compare cardanol ethoxylates derivatives as asphaltene dispersants in comparison with commonly used phenolic resins chemistries. To characterize the effects of cardanol chemistries, a series of laboratory tests were conducted. The thermo-electric properties of the crude oils were studied both with and without chemical treatments to establish state of asphaltenes and their disaggregation. Optical dispersion testing confirmed whether cardanol formulations affected the sedimentation rate and particle size distribution of flocculated asphaltenes within the oil matrix. An Asphaltene Dynamic Deposition Loop (ADDL) test verified the effectiveness of the cardanol ethoxylates on the overall asphaltene deposition rate under flow conditions. Finally, the rheology and viscoelastic properties of the treated oil were examined at various temperatures and shear rates with specific focus on steady state and low shear environments. Results were compared against commercially available resin-based products. In a thermodynamically stable crude oil medium, the asphaltene molecules exist in an equilibrium state and contributes least towards the overall thermo-electric reading of the test sample. Addition of an effective asphaltene inhibitor disrupts this equilibrium and disperses the polar asphaltene molecules within the crude matrix, leading to higher thermo-electric values. For the crude samples tested, it was observed that the addition of cardanol derivatives increased the thermo-electric response thus improving the asphaltene dispersion. Further validation of this improvement was confirmed with the optical dispersion test results. Relative to the blank or untreated sample, adding formulations with cardanol ethoxylates resulted in lower sedimentation rate and settling velocity of the heavy asphaltene fraction. Furthermore, effectiveness of cardanol as a surface-active agent that can avert the preferential sticking of the polar asphaltene fraction onto the metal surface of production and transportation flowlines was also assessed using the ADDL test. Lastly, the low-shear rheological analyses of the treated and untreated crude samples also corroborate synergistic efficiency of cardanol containing formulations to decrease the bulk sample viscosity. Cardanol ethoxylates belong to a class of surfactants derived from renewable and sustainable raw materials that can be considered as a viable option for upstream oilfield applications. Results from this study are quite encouraging and could set the stage for development of new asphaltene inhibitors and improve our capability to control asphaltene flocculation in more complex fluids and production systems including high asphaltenic crudes.
6
Rolón-Garrido, Víctor H., Jinji Luo, Manfred H. Wagner, and Martin Zatloukal. "Increase of Long-chain Branching by Thermo-oxidative Treatment of LDPE." In NOVEL TRENDS IN RHEOLOGY IV. AIP, 2011. http://dx.doi.org/10.1063/1.3604477.
7
Rolón-Garrido, Víctor Hugo, and Manfred Hermann Wagner. "Rheological characterization of thermal, thermo-oxidative and photo-oxidative degradation of LDPE." In NOVEL TRENDS IN RHEOLOGY VI. AIP Publishing LLC, 2015. http://dx.doi.org/10.1063/1.4918882.
8
Ling, Gerald H., Montgomery T. Shaw, Albert Co, Gary L. Leal, Ralph H. Colby, and A. Jeffrey Giacomin. "Thermo-Gelation of Surface-Modified Polyethylene Microgels from Fragmentation and Immiscible Blends." In THE XV INTERNATIONAL CONGRESS ON RHEOLOGY: The Society of Rheology 80th Annual Meeting. AIP, 2008. http://dx.doi.org/10.1063/1.2964884.
9
Ahmed, M. Elmuzafar, Abdullah Sultan, Abdulkareem AlSofi, and Hasan Al-Hashim. "Designing an Optimum Recipe for SP Flooding in Harsh Carbonate Reservoir Conditions High Temperature High Salinity." In SPE Conference at Oman Petroleum & Energy Show. SPE, 2022. http://dx.doi.org/10.2118/200246-ms.
Анотація:
Abstract Chemical-Enhanced-Oil-Recovery (CEOR) processes have been used for increasing oil recoveries from oil reservoirs following the primary recovery phase. At harsh reservoir conditions (high salinity and high temperature), many CEOR methods fail to achieve their objectives. This raises the challenge to design optimum recipes that tolerate these harsh conditions and hence attain maximum hydrocarbon recovery at the minimum possible cost. This paper evaluates the effectiveness of a Thermo-Viscosifying Polymer (TVP) and an Acrylamido Tertiary Butyl Sulfonate (ATBS)/acrylamide (AM) copolymer in mobilizing residual oil from carbonate. The surfactants are carboxybetaine based amphoteric surfactants SS-880 and SS-885. These candidates were selected based on an intensive evaluation process carried out in previous works at KFUPM, which includes fluid rheology, long-term thermal stability, interfacial tension (IFT), adsorption and microfluidic studies. Furthermore, contact angles were measured at high pressure and high temperature using a captive drop analyzer. Slug size and injection sequence optimization were also investigated through core-flooding experiments. Different injection scenarios including SW-SP-SW, SW-P-S-SW, SW-S-SW-P-SW and SW-P-SW-S-SW were also investigated to identify the best injection scenario. The coreflooding experiments were conducted at 90°C. The seawater (SW) used in this study is Arabian Gulf seawater having salinity of 57,000 ppm. The results showed that surfactant-polymer combination and SW-SP-SW injection scenario were the best in terms of oil recovery. The optimum chemical combination was found to be carboxybetaine (0.05% wt.) and ATBS/AM (0.25% wt.). It was also observed that the recoveries were increasing proportionally to the slug-size. This indicates that the chemical injection sequence and slug-size have a significant impact on ultimate oil recovery. This is believed to be due to the advantageous synergies between the chemicals. The core-flooding experiments confirmed the importance of optimizing the design of CEOR processes taking into consideration the type of chemicals, concentrations, slug sizes, and flooding sequence of the different combination of seawater (SW), surfactant (5) and polymer (P).
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Boluk, Yaman, Xiaoyi Lan, and Adetola Adesida. "Additive Manufacturing by Gel-in-Gel Printing." In The Nordic Rheology Conference. University of Stavanger, 2024. http://dx.doi.org/10.31265/atnrs.778.
Анотація:
Additive manufacturing by the 3D-printing processes enables solid free-form fabrication of three-dimensional objects directly from the digital images by melt prepolymers and gels following the post-curing of deposited polymers. Those processes have limitations due to long printing times, low-quality materials, and costs. The gel in gel printing by printing low viscosity materials in a support gel environment addresses those limitations. This process deposits a relatively low viscosity but curable liquids or gels into a medium of support gel. The support gel prevents the collapse or deformity of the printed object under its weight. Once the printing is completed, the object is cured, removed from the support bath, and rinsed off. The support gel can be reused. This sacrificial supporting gel has to be removed easily after 3D printing. There exists a very limited amount of materials suitable for printing and supporting the printed objects in a bath. Some of the support baths studied by different research groups are crosslinked polyacrylic copolymer microgels, granular gels, silica nanoparticle suspensions, and clay suspensions. The design of an appropriate supporting hydrogel bath poses several challenges. The supporting gel has to behave like Bingham plastic, not yielding until a threshold shear force is reached. In the meantime, its yield stress has to be low enough to accommodate nozzle movement. Besides supporting the deposited printing gel, the support bath must exhibit a high plateau shear elastic modulus, G ′. In addition, those viscoelastic properties have been thermo-reversible. Here, we discussed the role of yield stress of printing and support gels on gelling, shape integrity, and interlayer fusion.