Academic literature on the topic 'Gradient de porosité'
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Journal articles on the topic "Gradient de porosité":
Jancar, Josef, Klara Zarybnicka, Jan Zidek, and Frantisek Kucera. "Effect of Porosity Gradient on Mechanical Properties of Cellular Nano-Composites." Polymers 12, no. 3 (March 19, 2020): 681. http://dx.doi.org/10.3390/polym12030681.
Lei, Chuan, Jinglan Luo, Xiong Pang, Chi Li, Jiang Pang, and Yongkun Ma. "Impact of Temperature and Geothermal Gradient on Sandstone Reservoir Quality: the Baiyun Sag in the Pearl River Mouth Basin Study Case (Northern South China Sea)." Minerals 8, no. 10 (October 15, 2018): 452. http://dx.doi.org/10.3390/min8100452.
Martina, A. Della, and J. G. Hilborn. "Gradient porosity poly(dicyclopentadiene)." Journal of Materials Research 16, no. 7 (July 2001): 2045–52. http://dx.doi.org/10.1557/jmr.2001.0280.
Liu, Chong, and Nathaniel L. Rosi. "Ternary gradient metal–organic frameworks." Faraday Discussions 201 (2017): 163–74. http://dx.doi.org/10.1039/c7fd00045f.
Lynn, Heloise Bloxsom, and Bill Goodway. "Azimuthal P-P prestack amplitudes in the presence of oil-filled aligned porosity (fracture porosity)." Interpretation 8, no. 4 (October 14, 2020): SP109—SP133. http://dx.doi.org/10.1190/int-2020-0035.1.
Lootsik, M. D., N. O. Manko, R. O. Bilyy, M. M. Lutsyk (Jr.), and R. S. Stoika. "Analysis of chitosan molecular weight profile by electrophoresis in a porosity step gradient polyacrylamide gel." Ukrainian Biochemical Journal 94, no. 2 (July 11, 2022): 76–84. http://dx.doi.org/10.15407/ubj94.02.076.
Pradewa, Mohammad Resalto, Retno Gumilang Dewi, and Ucok W. R. Siagian. "Simulasi aliran fluida pada proses enhanced coalbed methane." Jurnal Teknik Kimia Indonesia 10, no. 3 (October 2, 2018): 157. http://dx.doi.org/10.5614/jtki.2011.10.3.7.
Wang, Hao, Guogang Yang, Qiuwan Shen, Shian Li, Fengmin Su, Ziheng Jiang, Jiadong Liao, Guoling Zhang, and Juncai Sun. "Effects of Compression and Porosity Gradients on Two-Phase Behavior in Gas Diffusion Layer of Proton Exchange Membrane Fuel Cells." Membranes 13, no. 3 (March 4, 2023): 303. http://dx.doi.org/10.3390/membranes13030303.
Mulsow, Sandor, Bernard P. Boudreau, and John A. Smith. "Bioturbation and porosity gradients." Limnology and Oceanography 43, no. 1 (January 1998): 1–9. http://dx.doi.org/10.4319/lo.1998.43.1.000i.
Mulsow, Sandor, Bernard P. Boudreau, and John N. Smith. "Bioturbation and porosity gradients." Limnology and Oceanography 43, no. 1 (1998): l—9. http://dx.doi.org/10.4319/lo.1998.43.1.000l.
Dissertations / Theses on the topic "Gradient de porosité":
Boulvert, Jean. "Traitements acoustiques à porosité contrôlée pour atténuation optimale." Thesis, Le Mans, 2020. http://www.theses.fr/2020LEMA1033.
This thesis exploits some of the new possibilities offered by additive manufacturing to design and optimize treatments for sound attenuation consisting in porous materials. Additive manufacturing allows to control individually each pore of a material. The porous treatment design process is turned upside down: instead of searching through a catalogue of existing materials to solve a problem, it is possible to directly design the right material by adjusting its microstructure. This research is part of a plan to reduce aircraft engine noise but extends beyond the aeronautical field, both theoretically and in terms of possible applications. A predicting method of the acoustic behaviour of porous materials produced by additive manufacturing and taking into account the impact of manufacturing defects is first introduced. Porous materials with controlled graded properties are then studied. A method for optimizing microstructural or manufacturing parameters is developed. The ability of graded porous materials to attenuate frequencies too low to be attenuated by non-graded materials is then proven and the optimal gradient for broadband attenuation is defined. The impact of the wall thickness of the pores along with the impact of transverse propagation inside porous materials is studied. Finally, a metaporous treatment allowing broadband and sub-wavelength absorption is developed. The results of this research can be applied to create porous treatments with a high noise attenuation. The analytical and numerical models used in this research are based on the hypothesis of porous materials acoustically behaving as equivalent fluids. The results are physically analyzed and experimentally validated through impedance tube testing of specimens produced by additive manufacturing
Richart, Olivier. "Les substituts osseux en hydroxyapatite : Nouveau procédé de fabrication de pièces macroporeuses à gradient de porosité." Valenciennes, 1998. https://ged.uphf.fr/nuxeo/site/esupversions/cf762061-806c-4205-b695-3f16de038391.
Sirijarukul, Suksawat. "Elaboration de membranes à traces en poly(éthylènetéréphtalate) ayant un gradient linéaire de taille de pore et une porosité constante." Montpellier 2, 2007. http://www.theses.fr/2007MON20110.
A new type of polymer track-etch membrane was produced with a gradient of pore size and another gradient of pore density along the large dimension of the membrane. Those gradients are independently very well controlled and obtained by simple procedures. In a first step, the pore density gradient is created by displacing the poly(ethyleneterephthalate) –PET- film in front of a swift heavy ions beam of varying flux. In a second step, the pore size is controlled by dipping progressively the previously ion beam exposed film into an aqueous solution of 2N NaOH at 50°C. The relationship between both gradients at any position along the membrane is predetermined before preparation: we have chosen to maintain porosity constant with a linear gradient of pore size. Scanning electron microscopy measurements allowed verification of the existence of a cylindrical pore through the whole thickness (13 µm) of the PET film after exposure to UV light centred around 312 nm. A theoretical model has been proposed which describes tangential filtration in a channel where one wall is such a membrane: the case of constant permeability leads to relatively simple analytical expressions contrary to the case of constant porosity. One cell was built up and characterized by electrical and hydraulic measurements. The membrane hydrophobic character is attenuated at high pH (10-2N NaOH) by ionization of the carboxylic groups. We showed also that varying etching time to obtain a gradient of pore size did not induce a wettability gradient provided that the material was previously exposed to UV radiation
Landron, Thomas. "effets des gradients de porosité et de contrainte sur le comportement en fatigue à grand nombre de cycles de l’alliage d’aluminium AlSi9Cu3 coulé sous pression." Electronic Thesis or Diss., Paris, HESAM, 2023. http://www.theses.fr/2023HESAE091.
This research deals with the effect of porosity and stress gradients on the high-cycle fatigue behavior (HCF) of the high-pressure die-cast (HPDC) aluminum alloy AlSi9Cu3 used by the automotive industry. The components produced by HPDC are characterized by a high level of porosity compared to other casting processes. In addition, the porosity or defect distribution within a component is highly heterogeneous and the existence of a porosity gradient between the surface and the in-bulk material is notable. Defects of different nature and size are present, including defects formed by complex three-dimensional pore networks.To study the effects of the porosity and stress gradients on the HCF behavior, a test methodology based on reducing the thickness of as-cast specimens by machining was developed. Four geometries machined from the same as-cast specimens were tested in HCF under different loading modes: plane bending and tension-compression with a load ratio R=-1. The analysis of the fatigue failure surfaces, combined with fatigue results in the form of Wöhler curves shows that fatigue behavior is controlled by the interaction between the porosity gradient and the stress gradient. The position of the crack initiation site (surface or in-bulk), the nature of the critical defects, as well as the fatigue strength are entirely determined by these two gradients.The effect of defects on the fatigue behavior was analyzed using an approach based on the Kitagawa-Takahashi diagram and the stress intensity factor threshold (Kth). This analysis shows that the fatigue strength of the material is controlled by the size of the defects in terms of the Murakami parameter (√area). The wide range of defect size and the variety of defect types makes it possible to characterize the behavior of the material in both the short crack and long crack regimes. It is observed that the position of the crack initiation site (surface or in-bulk) has only a small effect on the fatigue behavior. Thanks to a comparison between the studied alloy and other gravity-cast aluminum alloys, it is shown that both the fatigue strength and the crack propagation behavior, is partly controlled by (a) the microstructural characteristics of alloys (grain size and secondary dendrite arm spacing (SDAS)) and by (b) the monotonic and cyclic mechanical behavior of the materials.The complexity of the defect distribution (type, size and spatial distribution) complicates the characterization and modeling of the kinetics of crack propagation and their interactions with defects. To investigate this, in-situ image correlation was used to monitor crack growth during fatigue tests, with the aim of observing the crack interaction with natural defects, in bending at R=-1. The analysis of the crack growth kinetics and the fatigue failure surfaces reveals a strong interaction between fatigue cracks and defects. These interactions cause rapid crack accelerations, which drastically reduce the fatigue life. A HCF crack propagation model is proposed using an averaging approach with the Paris law. The coefficients are adjusted using the crack monitoring tests. The comparison between the simulated Wöhler curves at initial iso-defect-size and the experimental Wöhler curves shows that the propagation approach is not sufficient to account for all the stages leading to fatigue failure. It is clearly highlighted that the initiation phase must be taken into account and that the fatigue damage mechanisms, associated with defects comprised of complex three-dimensional pore networks, are extremely complex.Keywords: High cycle fatigue (HCF), microstructural heterogeneity, porosity gradient, stress gradient, aluminum alloy, high-pressure die-casting, porosity networks, fatigue life, crack – defect interaction
Verdenelli, Martine. "Elaboration par procédé sol-gel de couches minces oxydes à gradient de porosité : évaluation en tant qu'interphases dans les composites à matrice céramique SiC-SiC." Lyon 1, 2002. http://www.theses.fr/2002LYO10203.
Boulesteix, Rémy. "Densification du grenat d'yttrium et d'aluminium pur ou dopé sous forme de céramiques transparentes : relation entre microstructure et propriétés optiques : élaboration de matériaux à gradient de concentration en néodyme." Limoges, 2009. http://www.theses.fr/2009LIMO4040.
Dominguez, Nicolas. "Modélisation de la propagation ultrasonore en milieu complexe : application au contrôle non destructif et à la caractérisation de la porosité dans les matériaux composites stratifiés." Toulouse 3, 2005. http://www.theses.fr/2006TOU30235.
Vieira, Nunes Antonio Idivan. "Transport d'ions sous l'effet d'un champ électrique en milieu poreux : applications à la séparation de terres rares par électrophorèse à focalisation." Vandoeuvre-les-Nancy, INPL, 1999. http://docnum.univ-lorraine.fr/public/INPL_T_1999_VIEIRA_NUNES_A_I.pdf.
Trivalent ions of rare earth elements have very similar properties and their difficult separation each from another is usually carried out by liquid-liquid extraction or ion exchange focalisation electrophoresis represehts an alternative route to the usual techniques. The purpose of this work consisted of the fundamental investigation of ion transport phenomena in electrophoretic processes. Focalisation electrophoresis is suitable for separation of amphoteric species such as rare earth ions, using a pH gradient in the cell and upon addition of a complexed agent e. G. EDTA. This technique relies upon the difference in isoelectrical points of the considered species, being under the form of free cation near the ano'de, and in the form of anionic complexed species doser to the cathode Rare earth species are submitted to the antagonist effects of diffusion and migration, enabling their focalisation to occur at the isoelectrial point, corresponding to nil value of their effective mobility. Following a literature survey on rare earth elements and electrophoresis processes, the document describes theoretical and experimental investigations of complexation equilibria of some rare earth elements, namely lanthanum, neodymium, praseodymium and cerium, depending on pH. Values for the isoelectrical points coulb be estimated. Transport and focalisation phenomena in view of rare earth separation, are dealt in the last chapter. Investigations were first carried out without forced circulation of the electrolyte solution and the transient behavior of the system allowed operating conditions to be design and built-up of a continuos device, more suitable to separation, and provided with 42 potential and 42 temperature sensors: the results of the preliminary runs, in form of variable profiles, are presented and discussed
Os fons trivalentes de terras raras apresentam propriedades muito proximas umas das outras, o que dificulta bastante a separaçao destes elementos, sendo a extraçao por solvente e troca de ions os unicos métodos mais usados na separaçao de terras raras. No entanto, a eletroforese à focalisaçao representa uma alternativa à separaçao de terras raras como mostra este trabalho que tem como objetivo fundamental estudar os fenomenos de transportes de ions num determinado processo. Através da técnica de eletroforese à focalizaçao, é possivel separar espécies ionicas anfotéricas, como por exemplo cations de terras raras, M+3, aplicando-se um gradiente de pH na célula de separaçao e utilizando um acido como agente complexante, como por exemplo o EDTA. 0 principio deste método é baseado na diferença dos pontos isoelétricos das espécies presentes sob a forma cationica proxima ao anodo ou sob a forma do complexo ionico proximo ao catodo. Os ions de terras raras estao sempre submetidos aos efeitos da diftisao e da migraçao o que os levam a focalizarem em seus pontos isoelétricos correspondentes a mobilidade efetiva nula. Apos um èstudo bibliognifico sobre as terras raras e os processos de separaçao por eletroforese, este relatorio de tese descreve as aproximaçoes teorico e experimental de equilfbrio de complexaçao de alguns elementos de terras raras, como por exemplo: lantanio, cério, praseodimio e neodimio, em funçao do pH, hem como a estimacao do ponto isoelétrico. Os fenomenos de transporte e de focalizaçao foram abordados no ultimo capftulo, o que nos permitiu de observar as condiçoes operacionais de focalizaçao de uma espécie sem o fluxo forçado de uma soluçao. A metodologia descrita anteriormente foi utilizada para a concepçao e a realizaçao de uma célula corn circulaçao continua da soluçao num sistema dotado de 42 captores de temperaturas e 42 de potenciais. Os resultados dos primeiros testes de focalizaçao e da separaçao de dois elementos de terras raras foram apresentados e discutidos sob a forma de perfis de diferentes parametros
PLúA, Carlos. "Développement d’une stratégie d’implémentation numérique pour milieu continu poreux de 2nd gradient basée sur les éléments finis isogéométriques, application à un milieu partiellement saturé." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI019/document.
During the last decade, Isogeometric Analysis (IGA) has drawn the attention of the Finite Element community to its superior capabilities over the standard Finite Element Method (FEM). The IGA concept uses the same basis functions used in Computed Aided Design (CAD) for the approximation of the unknown fields such as displacements, pore pressure or temperature in the Finite Element solution of a (possibly coupled) thermo– hydro–mechanical problem. Among the most relevant features of IGA, its smoothness, its convergence rate and particularly its intrinsic higher–order continuity between elements represent a definite improvement over the standard FEM, which allow to obtain significant computational advantages in terms of accuracy of the solution and computa- tional efficiency.This work attempts to exploit the characteristics of IGA for the numerical solution of coupled hydro–mechanical (HM) problems in saturated and partially saturated second gradient poro–elastoplastic geomaterials. On one hand, the second gradient model belonging to the theory of continua with microstructure ensures the objectivity of the results in presence of strain localization phenomena in terms of mesh independence of the numerical solution, which cannot be achieved with classical constitutive models without an internal length scale. On the other hand, the C1–continuity achievable by means of IGA basis functions allows a straightforward implementation of such higher order constitutive models, within a HM formulation derived from the classical mixture approach. In addition, the smoothness of the IGA basis functions proved to be very efficient in the modeling of coupled processes characterized by strong hydraulic gradients – such as the simulation of the downward propagation of a saturation front in a partially saturated slope subject to rainfall infiltration. Last but not least, it is worth noting that, as compared to the existing approaches based on Lagrange multipliers, the IGA approach to the solution of coupled hydro-mechanical (HM) problems in saturated and partially saturated second gradient materials allows a dramatic reduction in the number of degrees of freedoms required to achieve the same level of accuracy. This not only results in a significant increase of the computational efficiency, but also allows to extend the complete second gradient formulation to the analysis of realistic 3D problems, the solution of which has been presented in this work for the first time.The local second gradient poro–elastoplastic formulation developed in this work is implemented in the research-oriented code GeoPDEs, a Matlab open source IGA–FEM code developed at the University of Pavia. Based on the results obtained in a large series of representative 2D and 3D initial–boundary value problems analyzed in this work, it can be concluded that the combination of IGA and the second gradient elastoplasticity represents a powerful tool for the numerical simulation of geotechnical problems characterized by strong multiphysics couplings, highly nonlinear behavior of the soil, and strongly localized displacement and pore pressure gradients
Svatík, Juraj. "Funkční pěny s gradientem hustoty." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-401848.
Book chapters on the topic "Gradient de porosité":
Andertová, Jana, Jiří Havrda, and Radek Tláskal. "Functional Gradient Alumina Ceramics with Controlled Porosity." In Key Engineering Materials, 223–26. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-424-3.223.
Wen, Cui'e, Yasuo Yamada, A. Nouri, and Peter Hodgson. "Porous Titanium with Porosity Gradients for Biomedical Applications." In THERMEC 2006, 720–25. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-428-6.720.
An, Chung Min, Jung-Hoon Song, Inyoung Kang, and Nigel Sammes. "Characterization of an Anode-Supported Planar Solid Oxide Fuel Cell with a Porosity Concentration Gradient." In Advances in Solid Oxide Fuel Cells V, 75–81. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2010. http://dx.doi.org/10.1002/9780470584316.ch6.
Castagna, S., S. Olivella, A. Lloret, and E. E. Alonso. "Experimental and Numerical Investigation of Porosity Variations in Saline Media Induced by Temperature Gradients." In Computational Methods for Flow and Transport in Porous Media, 327–38. Dordrecht: Springer Netherlands, 2000. http://dx.doi.org/10.1007/978-94-017-1114-2_22.
de Hazan, Yoram, Maciek Wozniak, Judit Heinecke, Gregor Müller, Veronika Märkl, and Thomas Graule. "Shaping Radiation Curable Colloidal Dispersions - From Polymer/Ceramic Fibers and Microspheres to Gradient Porosity Ceramic Bulk Materials." In Advanced Processing and Manufacturing Technologies for Structural and Multifunctional Materials IV, 85–95. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2010. http://dx.doi.org/10.1002/9780470944066.ch8.
Rothe, G. M. "ELECTROPHORESIS | Porosity Gradient Gels." In Encyclopedia of Separation Science, 1315–42. Elsevier, 2000. http://dx.doi.org/10.1016/b0-12-226770-2/03621-8.
Kühl, Michael, and Niels Peter Revsbech. "Biogeochemical Microsensors For Boundary Layer Studies." In The Benthic Boundary Layer, 180–210. Oxford University PressNew York, NY, 2001. http://dx.doi.org/10.1093/oso/9780195118810.003.0008.
Kralj, Polona. "Submarine Stratovolcano Peperite Syn-Formational Alteration - A Case Study of the Oligocene Smrekovec Volcanic Complex, Slovenia." In Updates in Volcanology - Transdisciplinary Nature of Volcano Science. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95480.
Cantor, Brian. "Fick’s Laws." In The Equations of Materials, 141–61. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198851875.003.0007.
Narwade, Avinash R., and Dr Siddharth K. Undirwade. "CASTING DESIGN AND SIMULATION OF BEARING BLOCK USING AUTO CAST SOFTWARE FOR DEFECT MINIMIZATION WITH EXPERIMENTAL VALIDATION." In Futuristic Trends in Mechanical Engineering Volume 3 Book 8, 206–16. Iterative International Publishers, Selfypage Developers Pvt Ltd, 2024. http://dx.doi.org/10.58532/v3bkme8p6ch5.
Conference papers on the topic "Gradient de porosité":
Fu, Pei, Jian Yang, and Qiu-Wang Wang. "EFFECTS OF GRADIENT POROSITY AND GRADIENT PARTICLE ON PERFORMANCES OF PLANAR SOFCS." In International Heat Transfer Conference 16. Connecticut: Begellhouse, 2018. http://dx.doi.org/10.1615/ihtc16.ecl.023190.
Iverson, William P. "Permeability estimation from sonic versus porosity gradients." In SEG Technical Program Expanded Abstracts 1990. Society of Exploration Geophysicists, 1990. http://dx.doi.org/10.1190/1.1889911.
Afandi, Yaman, Giacinta Parish, and Adrian Keating. "Study of Porosity Gradient in Released Porous Silicon Microstructures." In 2018 Conference on Optoelectronic and Microelectronic Materials and Devices (COMMAD). IEEE, 2018. http://dx.doi.org/10.1109/commad.2018.8715242.
Jurecka, Stanislav, Kentaro Imamura, Taketoshi Matsumoto, and Hikaru Kobayashi. "Reflectance analysis of porosity gradient in nanostructured silicon layers." In Photonics Prague 2017, edited by Petr Páta and Karel Fliegel. SPIE, 2017. http://dx.doi.org/10.1117/12.2292723.
Hajian, Rozhin, and Justin Jaworski. "The Steady Aerodynamics of Quiet Airfoils with Porosity Gradients." In 45th AIAA Fluid Dynamics Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2015. http://dx.doi.org/10.2514/6.2015-2304.
Javalagi, Mohan I., and William P. Iverson. "Permeability Estimation From Sonic-Transit-Time Versus Porosity Gradients." In SPE Annual Technical Conference and Exhibition. Society of Petroleum Engineers, 1996. http://dx.doi.org/10.2118/36658-ms.
Fu, Pei, Min Zeng, and Qiuwang Wang. "Effect of Gradient Anode on Mass Transfer Performance for Anode-Supported Planar Solid Oxide Fuel Cells." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-66095.
Hajian, Rozhin, and Justin W. Jaworski. "Steady Aerodynamics of Thick and Cambered Airfoils with Porosity Gradients." In 54th AIAA Aerospace Sciences Meeting. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2016. http://dx.doi.org/10.2514/6.2016-0855.
Roos, Frederick. "Combined effects of surface porosity and pressure gradient on turbulent boundary layers." In 37th Aerospace Sciences Meeting and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1999. http://dx.doi.org/10.2514/6.1999-1014.
Arab, Majid, and Majid Majidi. "Experimental and Numerical Study of Porosity Gradient in a Stirling Engine Regenerator." In WCX™ 17: SAE World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2017. http://dx.doi.org/10.4271/2017-01-0148.