Littérature scientifique sur le sujet « Laws of wetting »
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Articles de revues sur le sujet "Laws of wetting"
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Voinov, O. V. « Asymptotic laws of wetting hydrodynamics ». Doklady Physics 50, no 7 (juillet 2005) : 380–84. http://dx.doi.org/10.1134/1.2005365.
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Fondecave, R., et F. Brochard Wyart. « Wetting laws for polymer solutions ». Europhysics Letters (EPL) 37, no 2 (10 janvier 1997) : 115–20. http://dx.doi.org/10.1209/epl/i1997-00120-y.
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Fan, Qianwen, Liangjun Fei, Penghui Zhao, Fangyuan Shen et Yalin Gao. « Study on Soil Water and Nitrogen Transport Characteristics of Unidirectional Intersection Infiltration with Muddy Water Fertilization Film Hole Irrigation ». Agriculture 14, no 12 (17 décembre 2024) : 2314. https://doi.org/10.3390/agriculture14122314.
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This study investigated the effects of film hole diameter and soil bulk density on the unidirectional intersection infiltration laws of muddy water fertilization film hole irrigation. Indoor soil box infiltration experiments were conducted. The thickness of the sediment layer, cumulative infiltration amount per unit area, vertical wetting front transport distance, moisture distribution in the wetting body, and nitrate and ammonium nitrogen transport laws were observed and analyzed. The results indicated that both the thickness of the sediment layer and the cumulative infiltration per unit area are inversely correlated with film hole diameter and soil bulk density. Conversely, the vertical wetting front transport distance and nitrogen content are positively correlated with film hole diameter, while exhibiting a negative correlation with soil bulk density. Notably, the initial point of intersection for the moist body was located below the soil surface, with the peak vertical soil moisture content at the intersection approximately 1.5 cm beneath the surface. The distribution pattern of soil nitrate nitrogen at the conclusion of infiltration mirrored that of water content, characterized by a sharp decline near the wetting front. In contrast, soil ammonium nitrogen content decreased significantly in the shallow soil layer as soil depth increased, without a corresponding abrupt decrease near the wetting front. These findings may provide a theoretical foundation for future research on the intersection infiltration laws of muddy water fertilization through film hole irrigation.
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Wang, Boxin, Ruichang Fang, Xu Chai et Qing Wang. « Transportation Laws for Carbonate and Sulfate Ions in Concrete Based on Compartment Model ». Advances in Civil Engineering 2020 (23 juillet 2020) : 1–10. http://dx.doi.org/10.1155/2020/1769186.
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Transportation of carbonate and sulfate ions in concrete under the drying-wetting cycle environment is similar to the ingression and elimination of medicine in human body. Given this similarity, such a process is described dynamically using the classic compartment model in pharmacokinetics. The compartment model was applied to predict the content of carbonate and sulfate ions in different regions of concrete. Factors such as water-cement ratio, salt category, carbonate-ion and sulfate-ion attack depth, and drying-wetting cycle were synthetically considered in the compartment model. In conjunction with the prediction value of the compartment model, the experiment data uniformly distributed two sides of the model curve, and the difference is within the accepted range, thus verifying the reliability of the model prediction consequence. The compartment model in this article provides references for predicting the drying-wetting varied cycles and ions attack depth of concrete under carbonate and sulfate ions attack.
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Parmigiani, A., C. Huber, O. Bachmann et B. Chopard. « Pore-scale mass and reactant transport in multiphase porous media flows ». Journal of Fluid Mechanics 686 (30 septembre 2011) : 40–76. http://dx.doi.org/10.1017/jfm.2011.268.
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AbstractReactive processes associated with multiphase flows play a significant role in mass transport in unsaturated porous media. For example, the effect of reactions on the solid matrix can affect the formation and stability of fingering instabilities associated with the invasion of a buoyant non-wetting fluid. In this study, we focus on the formation and stability of capillary channels of a buoyant non-wetting fluid (developed because of capillary instabilities) and their impact on the transport and distribution of a reactant in the porous medium. We use a combination of pore-scale numerical calculations based on a multiphase reactive lattice Boltzmann model (LBM) and scaling laws to quantify (i) the effect of dissolution on the preservation of capillary instabilities, (ii) the penetration depth of reaction beyond the dissolution/melting front, and (iii) the temporal and spatial distribution of dissolution/melting under different conditions (concentration of reactant in the non-wetting fluid, injection rate). Our results show that, even for tortuous non-wetting fluid channels, simple scaling laws assuming an axisymmetrical annular flow can explain (i) the exponential decay of reactant along capillary channels, (ii) the dependence of the penetration depth of reactant on a local Péclet number (using the non-wetting fluid velocity in the channel) and more qualitatively (iii) the importance of the melting/reaction efficiency on the stability of non-wetting fluid channels. Our numerical method allows us to study the feedbacks between the immiscible multiphase fluid flow and a dynamically evolving porous matrix (dissolution or melting) which is an essential component of reactive transport in porous media.
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Andreotti, Bruno, et Jacco H. Snoeijer. « Statics and Dynamics of Soft Wetting ». Annual Review of Fluid Mechanics 52, no 1 (5 janvier 2020) : 285–308. http://dx.doi.org/10.1146/annurev-fluid-010719-060147.
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The laws of wetting are well known for drops on rigid surfaces but change dramatically when the substrate is soft and deformable. The combination of wetting and the intricacies of soft polymeric interfaces have provided many rich examples of fluid–structure interactions, both in terms of phenomenology and from a fundamental perspective. In this review we discuss experimental and theoretical progress on the statics and dynamics of soft wetting. In this context we critically revisit the foundations of capillarity, such as the nature of solid surface tension, the microscopic mechanics near the contact line, and the dissipative mechanisms that lead to unexpected spreading dynamics.
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Wallmeyer, Bernhard, Sarah Trinschek, Sargon Yigit, Uwe Thiele et Timo Betz. « Collective Cell Migration in Embryogenesis Follows the Laws of Wetting ». Biophysical Journal 114, no 1 (janvier 2018) : 213–22. http://dx.doi.org/10.1016/j.bpj.2017.11.011.
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Henkel, Christopher, Jacco H. Snoeijer et Uwe Thiele. « Gradient-dynamics model for liquid drops on elastic substrates ». Soft Matter 17, no 45 (2021) : 10359–75. http://dx.doi.org/10.1039/d1sm01032h.
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The presented simple long-wave gradient-dynamics model for soft wetting recovers the double transition for static drops and spreading laws on elastic substrates. It allows one to consider the influence of substrate softness on coarsening.
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Erofeev, Daniil A., et Leonid N. Mashlyakovsky. « FABRICATION AND APPLICATION OF HYDROPHOBIC SILICON CONTAINING POLYURETHANE COATINGS. PART TWO. (REVIEW) ». Bulletin of the Saint Petersburg State Institute of Technology (Technical University) 64 (2023) : 40–51. http://dx.doi.org/10.36807/1998-9849-2023-64-90-40-51.
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It is well known, that water drops tend to easily flow down from lotus leaves because of low wetting degree. In the first part of the review, we discussed the basic concept of wetting theory and different limits of existing models. The unsolved questions in the theory of wetting did not slow the development of methods of hydrophobic coatings fabrication. At present, coatings with low wetting degree are implemented in different industry fields. However, fabrication of coatings with stable hydrophobic properties is still difficult. That problem is especially serious for highly- and superhydrophobic coatings. The second part of the review describes the methods of fabrication of hydrophobic, highly- and superhydrophobic polyurethane coatings. We briefly mention the chemical reactions, which lead to polyurethanes obtaining, methods of hydrophobic coatings fabrication, and their application fields. Special attention is focused on the analysis of the surface parameters in order to establish general laws for producing hydrophobic, highly-hydrophobic and super-hydrophobic polyurethane silicon coatings
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Leibler, Ludwik, et Ahmed Mourran. « Wetting on Grafted Polymer Films ». MRS Bulletin 22, no 1 (janvier 1997) : 33–37. http://dx.doi.org/10.1557/s0883769400032310.
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Studying the properties of endanchored polymer layers has been a fashionable occupation for numerous physicists, chemists, and material scientists for more than 10 years. Theoreticians have realized that grafted macromolecules are nice statistical objects wriggling around under thermal motion, which give rise to nontrivial long-range entropic effects. These can be described by elegant scaling laws and analogies with quantum or classical mechanics. For experimenters the area turned out to be a marvelous playground in which both very simple and sophisticated techniques such as x-ray or neutron scattering and reflectivity, nuclear magnetic resonance (NMR), Rutherford backscattering, and optical and atomic force microscopy (AFM) have been used to discover interesting and subtle phenomena. All this effort was also motivated by the importance of grafted layers in applications such as paints, adhesives, lubricants, colloidal stabilizers, and composite materials. By anchoring a thin, soft polymer layer to a solid surface, one can tune the surface properties. In this short article, we will discuss how the wetting and spreading of liquids and polymer melts can be profoundly altered by the presence of such protective layers.
Thèses sur le sujet "Laws of wetting"
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Bami, Chatenet Yann. « Modélisation analytique du mouillage sur des topographies multi-échelles complexes pour le design biomimétique de surfaces superhydrophobes ». Electronic Thesis or Diss., Ecully, Ecole centrale de Lyon, 2024. http://www.theses.fr/2024ECDL0053.
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Une goutte d’eau roule sur une feuille de lotus sacré mais elle adhère à un pétale de rose. Ces deux surfaces présentent, aux échelles micrométrique et nanométrique, une morphologie complexe. Quel est alors le lien entre leur mouillabilité et leur morphologie multi-échelles ? L’objectif de cette thèse est de mener une approche biomimétique pour la conception de surfaces superhydrophobes tout en comprenant les stratégies mises en œuvre par le vivant. Dans une première partie, nous caractérisons des surfaces végétales dont le régime de mouillage est observé directement par microscopie confocale à balayage laser. Nous démontrons que le lotus sacré produit un mouillage en régime mixte métastable caractérisable par une profondeur d’ancrage non nulle des lignes triples à l’équilibre. De plus, nous observons un régime hiérarchique de Wenzel-Wenzel sur le pétale de rose, à rebours des hypothèses de la littérature. De ces observations, nous tirons des questionnements clés que nous confrontons aux modèles actuels de la littérature. Dans une seconde partie, nous adaptons deux approches des phénomènes capillaires à l’étude du piégeage d’air sur une topographie multi-échelles et introduisons la paramétrisation nécessaire à l’étude des régimes de mouillage mixte et de leur robustesse. Nous prédisons la profondeur d’ancrage à l’équilibre sur le lotus sacré en mettant en lumière le rôle de sa topographie nanométrique. Enfin, nous décrivons les mécanismes gouvernant les mouvements à l’avancée et à la reculée et leurs propagations par récurrence à travers les échelles topographiques constituant une surface en introduisant la notion de mouvement précurseur. Nous démontrons l’effet de la profondeur d’ancrage à l’équilibre sur l’hystérèse d’angle de contact et le rôle des sous-échelles topographiques sur la robustesse du régime de piégeage d’air. À travers l’étude expérimentale de surfaces fabriquées par photolithographie, nous confrontons ce modèle à la réalité. Enfin, dans une troisième partie, nous transposons les conclusions issues de ce modèle en un cahier des charges pour la conception de surfaces superhydrophobes robustes, déclinons la stratégie mise en œuvre par la feuille du lotus sacré et proposons deux voies de fabrication de surfaces déperlantes, par recristallisation de cire naturelle et polymérisation deux-photonsA drop of water rolls on the sacred lotus leaf but stay fiercely anchored onto a rose petal. Both surfaces display a complex morphology at the micrometric and nanometric scales. Therefore, one could ask: how are their wettability and their morphology related? The purpose of this dissertation is to carry out a biomimetic approach in order to conceive superhydrophobic surfaces and to better understand nature’s strategies. In a first part, vegetal surfaces have been characterized by directly observing the wetting state they produce with the help of confocal microscopy. We demonstrate the fact that the sacred lotus produces a metastable mixed-state wetting that is characterized by a finite equilibrium anchorage depth of triple lines. On the other hand, a Wenzel-Wenzel hierarchical wetting state is observed on the rose petal, in spite of what literature suggests. From these experiments, key questions have been highlighted and confronted to the current models available within the literature. In a second part, two approaches to capillary phenomena have been adapted to the study of a composite wetting state produced by a multiscale topography. We introduce a complete parameterization allowing us to tackle the problem of the mixed-state wetting and its stability, to predict the value of the equilibrium anchorage depth on the sacred lotus leaf and to identify the contribution of its nanoscale topography to its wetting. Then, we thoroughly describe the mechanisms underlying the advancing and receding motions of triple lines and their recursive propagation across every topographical scale constituting a surface by introducing the notion of precursor motion. We highlight the effect of the equilibrium anchorage depth on the contact angle hysteresis and the role played by topographical subscales on the robustness of the composite wetting state. Through the experimental study of model surfaces manufactured by photolithography, we compare our predictions to reality. Eventually, in a third part, the conclusions drawn from our model are transposed into technical specifications for the conception of robust superhydrophobic surfaces, the strategy of the sacred lotus leaf is thoroughly described and two promising manufacturing processes are proposed through the recrystallization of natural wax and two-photon polymerization
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Vybornova, Olga [Verfasser], et Lars [Akademischer Betreuer] Kutzbach. « Effect of re-wetting on greenhouse gas emissions from different microtopes in a cut-over bog in Northern Germany / Olga Vybornova ; Betreuer : Lars Kutzbach ». Hamburg : Staats- und Universitätsbibliothek Hamburg, 2017. http://d-nb.info/1137624906/34.
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Géraud, Baudouin. « Mouillage et dynamique confinée de fluides complexes ». Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10170.
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Les fluides complexes tels que les gels, les pâtes ou les émulsions présentent une large gamme d'applications, tant dans la vie quotidienne que dans l'industrie. Parmi ces fluides, les fluides dits ”à seuil” se comportent soit comme des solides élastiques, soit comme des fluides nonnewtoniens selon la contrainte qu'on leur applique. Ces propriétés sont décrites par des lois phénoménologiques (telle que la loi d'Herschel Bulkley), bien que leurs origines soient encore mal comprises. Dans cette thèse, nous nous intéressons à la question des petites échelles, où la structure et les phénomènes interfaciaux jouent des rôles prépondérants dans les écoulements. Ce travail expérimental a été essentiellement mené sur du carbopol, un microgel de polymères et un fluide à seuil modèle. L'étude se concentre essentiellement sur trois points : – La caractérisation rhéologique et structurale des échantillons. L'accent est porté sur l'influence du protocole de préparation sur les propriétés des gels.– Le cas des écoulements confinés de fluides complexes. Ce travail met en évidence l'existence d'effets non-locaux aux échelles micrométriques, faisant intervenir une taille caractéristique interprétée dans le cadre du modèle de fluidité. – Les ascensions capillaires de fluides complexes, aux échelles millimétriques. En revisitant l'expérience classique des ascensions capillaires dans le cas des fluides complexes, cette étude propose une extension de la loi de Jurin au cas des fluides à seuil. Il est montré que cette expérience simple permet de mesurer la tension de surface et quelques paramètres rhéologiques de fluides complexes tels que le seuil et l'exposant d'Herschel-BulkleyComplex fluids such as gels, pastes or emulsions have a wide range of applications, both in everyday life and in the industry. Among them, Yield Stress Fluids (YSF) behave either as solids or as non-Newtonian fluids depending on the shear stress applied. These features are modeled by phenomenological laws ( such as the Herschel-Bulkley one ) although their origins are still poorly understood. In this thesis, we focus on the issue of small lengthscales where the structure and interfacial phenomena play predominant roles in the flows. This experimental work was essentially carried out on carbopol, a polymer microgel and a model YSF. The study mainly focuses on three points : – The rheological and structural characterization of the samples. The emphasis is put on the influence of the preparation protocol on the microgel properties. – The case of confined flows of complex fluids. This work highlights the existence of nonlocal effects at the micrometer scales, involving a characteristic length, interpreted in the frame of the fluidity model. – Capillary ascents of complex fluids, involving millimeter scales. This work suggests an extension of Jurin’s law to the case of YSFs. It is shown that this simple experiment allows to measure the surface tension and some rheological parameters of complex fluids such as the yield stress and the Herschel-Bulkley exponent
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Perkins, Richard Mark. « PIV Measurements of Turbulent Flow in a Rectangular Channel over Superhydrophobic Surfaces with Riblets ». BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5547.
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In this thesis I investigate characteristics of turbulent flow in a channel where one of the walls has riblets, superhydrophobic microribs, or a hybrid surface with traditional riblets built on a superhydrophobic microrib surface. PIV measurements are used to find the velocity profile, the turbulent statistics, and shear stress profile in the rectangular channel with one wall having a structured test surface. Both riblets and superhydrophobic surfaces can each provide a reduction in the wall shear stress in a turbulent channel flow. Characterizing the features of the flow using particle image velocimetry (PIV) is the focus of this research. Superhydrophobicity results from the combination of a hydrophobic coating applied to a surface with microrib structures, resulting in a very low surface energy, such that the fluid does not penetrate in between the structures. The micro-rib structures are aligned in the streamwise flow direction. The riblets are larger than the micro-rib structure by an order of magnitude and protrude into the flow. All the test surfaces were produced on silicon wafers using photolithographic techniques. Pressure in the channel is maintained below the Laplace pressure for all testing, creating sustainable air pockets between the microribs. Velocity profiles, turbulent statistics, shear stress profiles, and friction factors are presented. Measurements were acquired for Reynolds numbers ranging from 4.5x10^3 to 2.0x10^4. Modest drag reductions were observed for the riblet surfaces. Substantial drag increase occurred over the superhydrophobic surfaces. The hybrid surfaces showed the greatest drag reduction. Turbulence production was strongly reduced during riblet and hybrid tests.
Livres sur le sujet "Laws of wetting"
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Kessler, M. Subjectieve bestanddelen in bijzondere wetten. Deventer : Gouda Quint, 2001.
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Institute, Pennsylvania Bar. Wettick on discovery. [Mechanicsburg, Pa.] : Pennsylvania Bar Institute, 2000.
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Stanton, Wettick R., et Pennsylvania Bar Institute, dir. Wettick on discovery. Harrisburg, Pa : Pennsylvania Bar Institute, 1994.
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Belgium. Aanvullende wetten Burgerlijk wetboek : Bijgewerkt tot 21 juni 1993. Antwerpen : MAKLU, 1993.
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Floris, O. A. M. Grondrechtenbescherming door algemene wetten. Zwolle : W.E.J. Tjeenk Willink, in samenwerking met het Nederlands Instituut voor Sociaal en Economisch Recht, 1994.
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Netherlands. Stelselherziening sociale zekerheid : Wetten. Den Haag : Staatsuitgeverij, 1986.
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Katharina, Boele-Woelki, dir. Tekstuitgave IPR : Verdragen en wetten internationaal privaatrecht en aanverwante rechtsgebieden. Deventer : Kluwer, 1991.
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Netherlands. Verzekeringsrechtelijke regelingen, wetten, uitvoeringsbesluiten en verdragen. Deventer : Kluwer, 1999.
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Belgium. Strafwetboek : Wetboek van Strafvordering : Bijzondere wetten. 2e éd. Antwerpen : Maklu, 2006.
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(Gert), Vermeulen G., et De Bondt Wendy, dir. Strafwetboek : Wetboek van Strafvordering : bijzondere wetten. 2e éd. Antwerpen : Maklu, 2008.
Trouver le texte intégralChapitres de livres sur le sujet "Laws of wetting"
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Yuan, Leqi, Kun Cheng, Haozhi Bian, Yaping Liao et Chenxi Jiang. « Numerical Simulation of Flow Boiling Heat Transfer in Helical Tubes Under Marine Conditions ». Dans Springer Proceedings in Physics, 1015–30. Singapore : Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1023-6_86.
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AbstractLead-based cooled reactors in most countries and some small reactors at sea use helical tube steam generators. Compared with U-tubes, the convection heat transfer coefficient in the spiral tube is higher, the structure is more compact, and the secondary flow is generated under the action of centrifugal force and gravity, which can achieve the effect of wetting the inner wall of the tube. However, due to the importance of the steam generator in the reactor and the complexity of the flow and boiling in the helical tube, the aggregation behavior of bubbles, the distribution of the two-phase interface and the secondary flow in the tube will significantly affect the heat transfer characteristics, so the gas-liquid phase in the tube is studied. Distribution, changes in heat transfer coefficients, and fluid flow characteristics are very important.In order to study the boiling heat transfer characteristics of helical once-through steam generators under static and marine conditions to provide safe and reliable energy supply for offshore facilities such as marine floating, this study uses STAR-CCM+ software, VOF method and Rohsenow boiling model to study the heat transfer capacity and flow characteristics of flow boiling in a helical tube under swaying and tilting conditions. The gas-liquid phase distribution characteristics, secondary flow variation characteristics and convective heat transfer coefficient of the fluid under different swing functions and inclined positions are obtained by numerical calculation, and the law of physical parameters changing with the cycle is found. The research results show that the secondary flow and heat transfer capacity in the tube change with the cycle, and the change is most obvious at the tube length of 0.8m. 5% of the normal condition; when the inclination angle is 45°, the maximum increase of the convection heat transfer coefficient is 16.8%, and the maximum decrease is 6.6%.
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Tabeling, Patrick. « Hydrodynamics of microfluidics 2 : droplets ». Dans Introduction to Microfluidics, 162–244. 2e éd. Oxford University PressOxford, 2023. http://dx.doi.org/10.1093/oso/9780192845306.003.0004.
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Abstract This concerns the hydrodynamics of microfluidics, in the presence of free interfaces. In particular bubbles an droplets in microchannels. Basics of interfaces are shown, including discussions on capillarity, surface tension Laplace law, wetting. Surfactants, which play a major role in microfluidics, are presented. Various laws are discussed: Washburn law, Landau Levich, Breteherton, Rayleigh Plateau. These notions are used to discuss the behaviour of droplets in microfluidic systems: breakup, coalescence, bubble pressure drop, droplet production.
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Tsybulskyi, Vitalii. « IMPROVEMENT OF CALCULATION METHOD OF ROAD PAVEMENT EMBANKMENT ON THE APPROACHES TO ROAD BRIDGES ». Dans Integration of traditional and innovation processes of development of modern science. Publishing House “Baltija Publishing”, 2020. http://dx.doi.org/10.30525/978-9934-26-021-6-41.
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The laws of unsaturated and capillary movement of water in soils are analyzed, which are complex and insufficiently studied, but significantly affect the condition of the ground. Experience in the design and construction of the subsoil has shown that during the excavation works can significantly change the conditions of soils and their water-thermal regime. Therefore, the characteristics of soils used in stability calculations should be determined taking into account the subsequent condition of the soil in the conditions of occurrence, as well as the possible change of these conditions during construction and maintenance. One of the urgent tasks is to improve the methods of regulating the water-thermal regime of roads. By changing the conditions of its course or the type of water-thermal regime itself, significant successes can be achieved in improving the maintenance of roads, engineering and transport facilities. Dangerous effect of these factors on the embankment of the ground is manifested in the formation of wetting, wetting of the soil and layers of pavement, resulting in reduced density, strength of soils, subsidence, swelling and loss of continuity due to cracking. As a result, the strength of the road structure, the flatness of the carriageway, the durability of the pavement and the adhesion of the wheels to the roadway are reduced. The most dangerous for roads are moisture accumulation, freezing, thawing of the ground, intensive heating and intensive cooling of the layers of pavement. The analysis of regularities of formation of a water-thermal regime of a ground and its regulation at the expense of the device of optimum capillary-interrupting layers is carried out. The laws of soil moisture when raising capillary water showed that when the layer of the embankment with a high coefficient of impregnation is dehydrated over the layer with a lower coefficient, the speed of moving capillary water into the upper soil layers drops sharply. This fall occurs as a result of changes in the relationship between the driving forces of the menisci and the forces of resistance of capillary water in the soil. The process of unsaturated movement of water in the soil is determined by the combination of many factors that characterize the capillary system of the soil. The calculation uses complex indicators of soil water movement conditions, which are established experimentally for each variety and soil density at optimal humidity, as well as water filtration coefficients in the soil. To establish the relationship between these experimental data and the required values that determine the capillary system of the soil, the filtration of water in the soil was considered. Determining the optimal capillary system of the soil and establishing the unstable distribution of own capillary water in the structures of high embankments will ensure the strength of approaches to road bridges. The method of calculating the determination of the optimal composition of the road layers taking into account the processes of water-thermal regime and capillary movement of water has been improved. The algorithm of calculation in the program Microsoft Excel for selection of optimum structure of a ground cloth of a high embankment on approaches to automobile bridges is offered.
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Liu C. et Muraleetharan K.K. « Coupled hydraulic and mechanical behavior of unsaturated soils : theory and validation ». Dans Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering. IOS Press, 2009. https://doi.org/10.3233/978-1-60750-031-5-452.
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Unsaturated soils are three-phase porous media consisting of a solid skeleton, pore water, and pore air. It is well known that the behavior of unsaturated soils is influenced heavily by matric suction. Soil water characteristic curves (SWCCs) are necessary to describe the hydraulic behavior (flow of water and air) in an unsaturated soil. SWCCs describe the relationship between the matric suction and the water content in unsaturated soils. SWCCs show hysteretic behavior depending on wetting/drying history of a soil. Recently geotechnical engineers have begun to realize that SWCCs also depend on the stress-strain history (mechanical behavior) of a soil. The hydraulic behavior of unsaturated soils, on the other hand, influences the mechanical behavior through matric suction. In order to predict the behavior of unsaturated soils, a comprehensive constitutive model for unsaturated soils is developed. The hysteresis in SWCCs is modeled using concepts that parallel the elastoplastic theory used to model stress-strain behavior of soils. Matric suction is used as the stress variable and volumetric water content is used as the strain variable in modeling the SWCCs. The model also captures the influence of stress-strain history on the SWCCs and the influence of SWCCs on the stress-strain behavior of soils through the use of an intergranular stress tensor and coupled elastoplastic hardening laws. The constitutive model is calibrated and validated using complex triaxial tests on Toyoura sand under both monotonic and cyclic loadings.
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A. Ali, Mohamed, Joël De Coninck et Hary L. Razafindralambo. « Wettability of Probiotic Powders : Fundamentals, Methodologies, and Applications ». Dans Wetting and Wettability - Fundamental and Applied Aspects [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.106403.
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Wettability is a macroscopic consequence of microscopic phenomena occurring at the fluid-solid interfaces. This functional property is crucial for the formulation of wettable powders in food and non-food sectors. Basically, powder wettability is mostly assessed through the contact angle measurements of solid particles reacting with dispersing media, by either the sessile drop method or the capillary rise technique. Among the most popular bioactive agents nowadays are probiotics and their metabolites, which are receiving a growing interest for their beneficial effects on our ecosystem health. As live functional ingredients, probiotics are mainly available in a powder form that is sensitive to the environmental stress factors during processing and storage steps. It is therefore crucial to understand and control their wettability, regarding their performance, dispersibility, and stability when probiotic particles come into contact with dispersing media and body fluids. The proposal chapter aims to review: (1) the theoretical aspects of powder wettability by considering compact and porous materials; (2) the analytical tools and methodologies of measurement, including sessile drop and capillary rise methods using models Lucas-Washburn equation and Darcy’s law; and (3) the applications to probiotic powders as functional ingredients in food and agricultural sectors.
Actes de conférences sur le sujet "Laws of wetting"
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de Boer, Maarten P., et P. C. T. de Boer. « Thermodynamics of Capillary Adhesion in MEMS ». Dans ASME/STLE 2004 International Joint Tribology Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/trib2004-64361.
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In this extended abstract, we briefly describe a thermodynamic model to treat capillary adhesion energies in MEMS. We first determine the constitutive laws of a capillary pendular ring bridging an asperity to a substrate. We find that the work of adhesion, W, depends on the surface separation rate. For the constant volume case (rapid surface separation), W = 2γ (where γ is the surface energy per unit area of the liquid-air interface), but if thermodynamic equilibrium is maintained (slow surface separation), W = γ. Thermodynamic analysis indicates that heat from the system walls can lower the work of adhesion at slow separation rates. We extend these constitutive laws to a simple multi-asperity surface in which the asperities are all of constant height. At low vapor partial pressures (p/psat), adhesion can be several orders of magnitude below γ because of incomplete wetting. As vapor partial pressure increases, condensing liquid fills in the geometric irregularities of the surface. As this filling takes place, W approaches 2γ for both the slow and rapid separation rates.
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Fukuta, Masato, et Yasushi Yamamoto. « Development of Boiling Heat Transfer Analysis Method ». Dans ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21679.
Texte intégralRésumé :
In this study, a numerical analysis method applicable to estimation of the boiling heat transfer has been developed. Currently, the experimental correlations or the empirical laws have been applied to evaluate the boiling heat transfer. Therefore, it is difficult to predict the effects of the change of the heated surface geometry, thermal-hydraulic conditions, the surface activation or modification, because out of the application range of these correlations. The purpose of this work is to construct the boiling two-phase analysis method for thermo-fluid phenomena, and to realize “Design-by-Analysis” independent on the experiments and empirical laws. For this purpose, it is important to predict steam-water interface structure characteristics of the two-phase flow directly. Until now, for evaluating the boiling phenomena, Diffusive Interface Model for the bubble interface tracking was applied. In this model, the steam-water interface is diffuse with a finite width, and values of the thermodynamic properties change between water and steam smoothly within the interface region. For evaluating the wettability of heated surface, the surface energy is estimated by using the phase-field model. The wetting phenomena during boiling are able to be analyzed directly with this model. We present the numerical results of nucleate pool boiling phenomenon by using the developed analysis method. We succeeded in simulating the boiling process, vapor bubbles nucleation, growth, and departure behavior on a heated surface. By present analysis method, it was confirmed that the boiling heat transfer coefficient could be evaluated quantitatively without the experimental correlations.
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Xiuping Tao et Hongwei Xin. « Optimization of Surface Wetting to Cool Broiler Chickens ». Dans 2003, Las Vegas, NV July 27-30, 2003. St. Joseph, MI : American Society of Agricultural and Biological Engineers, 2003. http://dx.doi.org/10.13031/2013.14101.
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Winter, Ian, et Michael Chandross. « Adhesion and Wetting of Liquid/Metal Interfaces ». Dans APS March Meeting - Las Vegas, Nevada, United States of America - March - 2023. US DOE, 2023. http://dx.doi.org/10.2172/2431785.
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Herescu, Alexandru, et Jeffrey S. Allen. « Film Deposition in Non-Wetting Tubes : An Experimental Film Thickness Law ». Dans ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-50217.
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Deposition of a liquid film on non-wetting tubular surfaces gives rise to the unexpected behavior of simultaneously coexisting thick and thin films. Experiments show that a discontinuity in the film thickness, a jump between the thick and thin films being laid from the meniscus towards the bounding moving contact line, occurs after a considerably thicker than the expected Bretherton film is deposited. Bretherton assumed the film to be uniform and, unlike the case of a non-wetting surface, the visco-capillary deposition process was not affected by the presence of a contact line. In reality this phenomenon lies at the confluence between a dewetting process and the deposition itself, being the result of the influence claimed by the dynamics of the zone adjacent to the moving contact line. The film thickness is calculated directly from the experimental data and a correlation is obtained by matching the measured and the theoretical shock velocities associated with the hydraulic jump. The non-wetting film is significantly thicker than Bretherton’s prediction and follows in turn a different law which is determined experimentally. The non-wetting film thickness is found to vary as hR4/3, hR being the Ca-dependent non-dimensional Bretherton film thickness.
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Petrovic, Milan M., Vladimir Stevanovic, Milica Ilic et Sanja Milivojevic. « Numerical Simulation of Pool Boiling With Two-Fluid Model and Grid-Resolved Heat Transfer Mechanisms ». Dans 2024 31st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/icone31-136496.
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Abstract Most nucleate boiling simulations are based on the Eulerian modelling of bulk liquid-vapour two-phase flow and subgrid presence of all mechanistically partitioned heat transfer modes in fluid control volumes in contact with the heated wall. Such mechanistic partitioning heat transfer approach predicts the total heat flux from the heated wall towards the boiling two-phase mixture as the sum of (i) the single-phase convection heat transfer from the heated wetted wall not covered with the rising bubbles, (ii) the transient conduction caused by the rewetting of the heated wall hot spot after the bubble detachment, known as quenching heat flux and (iii) the evaporation heat flux. Here presented research introduces a new approach to the numerical modelling of pool boiling based on the grid resolved mechanisms of boiling heat transfer. The spots of bubble growth and the wetted areas are distinguished and two grid resolved modes of heat transfer are considered: the conjugate heat transfer from the heated wall to the rising bubble at the bubble footprint until the bubble departure and the conjugate heat transfer from the heated wall to the wetting liquid. The constituents of the heat transfer model at the footprint of the bubble growth are the bubble residence time and the bubble departure diameter. The presented model is validated by experimental data from the literature. It was shown that the model can predict the wall temperature transient at bubble footprint location as well as the mean wall superheating. Appropriate modelling of vapour generation at the discrete locations of the bubble growth enables good prediction of two-phase mixture pattern in the boiling pool, the void fraction distribution along pool height and swell level position. Further analysis includes the application of both subgrid and grid resolved modelling approaches to the simulation of pool boiling under high heat fluxes. It is shown that the subgrid wall boiling model does not predict adequately the wall temperature transient behaviour and the void fraction distribution in the boiling pool under high heat fluxes, while the grid resolved model provides plausible results. Presented simulations are obtained with the in-house computer code based on the modified Semi-Implicit Method for Pressure Linked Equations (SIMPLE) for the solving of mass, momentum and energy balance equation for each phase and appropriate closure laws for the prediction of vapour-liquid interface transport phenomena.
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Ashraf, Shabina, et Jyoti Phirani. « Capillary Impregnation of Viscous Fluids in a Multi-Layered Porous Medium ». Dans ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-5168.
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Abstract Capillary impregnation of viscous fluids in porous media is useful in diagnostics, design of lab-on-chip devices and enhanced oil recovery. The impregnation of a wetting fluid in a homogeneous porous medium follows Washburn’s diffusive law. The diffusive dynamics predicts that, with the increase in permeability, the rate of spontaneous imbibition of a wetting fluid also increases. As most of the naturally occurring porous media are composed of hydrodynamically interacting layers having different properties, the impregnation in a heterogeneous porous medium is significantly different from a homogeneous porous medium. A Washburn like model has been developed in the past to predict the imbibition behavior in the layers for a hydrodynamically interacting three layered porous medium filled with a non-viscous resident phase. It was observed that the relative placement of the layers impacts the imbibition phenomena significantly. In this work, we develop a quasi one-dimensional lubrication approximation to predict the imbibition dynamics in a hydrodynamically interacting multi-layered porous medium. The generalized model shows that the arrangement of layers strongly affects the saturation of wetting phase in the porous medium, which is crucial for oil recovery and in microfluidic applications.
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Wang, Tao, Xuegong Hu, Chaohong Guo et Dawei Tang. « The Visualization Study of Contact Line Characteristics in Triangle Wetting Region of Rectangle Microgroove ». Dans ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels collocated with 3rd Joint US-European Fluids Engineering Summer Meeting. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30649.
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The paper acquires the images of triple phase contact line along the axial direction in microgroove triangle wetting region by the direct visualization means. The contact line images are processed by computer software, and the change law for triple phase contact line is obtained. The contact line angle between contact line and axial direction along microgroove is obtained by analyzing contact line. Results indicate that the length of contact line and the thickness of liquid film on side wall of microgroove reduce along with heat flux addition; but increase as the tilt angle increases. The contact line angle increases with the increase of tilt angle and the decrease of heat flux. In addition, changes of the length of contact line, the thickness of liquid film and the contact line angle for ethanol case is more significant than that for distilled water.
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Kawano, Riki, Kimiharu Yamazaki, Shinichi Kuramoto, Koichi Kato et Kazuyoshi Fushinobu. « Wetting Behavior of Droplet on Inclined Surface : From Inkjet Printing on Non-Paper Media ». Dans ASME 2023 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/ipack2023-111666.
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Abstract Inkjet printers are being developed to enable printing on surfaces other than paper, such as building walls, the ground, and clothes. The challenge for printers that print on surfaces other than paper is the formation of a liquid film after the ink has landed on the surface. On uneven surfaces other than paper, the droplets are affected by gravity and their shape is distorted, resulting in a reduction in image quality. To improve these problems, it is necessary to understand how high viscosity ink used in printing spread on the substrate. In this paper, it is examined whether the droplet motion model based on Newton’s second law of motion can explain the motion of highly viscous droplets. The results show that it is necessary to consider models that take into account changes in droplet shape and velocity over time and dynamic changes when the Reynolds number is large, and to establish a method for estimating Boc when the receding contact angle does not move.
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Chen, Sen, Zhen Wang, Jiangtao Zhang, Dahua Cai et Jiyun Zhou. « Life Prediction Model for Nuclear Power Plant Intake Structure Exposed to Chloride Environment Based on Similarity Principle ». Dans 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16002.
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Abstract Three environmental simulation experiments for accelerating the chloride ingress were designed based on the similarity principle and the actual Nuclear Power Plant (NPP) intake structure service environment parameters including alternate drying-wetting condition, immersion condition and salt spray condition. Different experiment conditions were designed for each three-simulation experiment condition based on the similarity principle. The temperature, chloride ion concentration and dry-wet cycle time ratio were selected parameters for alternation wetting-drying experiments. The temperature and chloride ion concentration were selected parameters for the salt spray experiment and immersion experiment. The distribution of chloride ion concentration along the depth of the concrete samples were measured every 30 days. The testing results showed that chloride ion diffusion depth is maximum under the dry-wet cycle test, chloride ion diffusion depth is minimum under salt spray test. The curves of the chloride ion concentration along depth increased firstly and then decreased, which is consistent with the two-dimension diffusion law. Finally, a life prediction model that can be used to predict the concrete structure of the existing coastal nuclear power plant was developed based on the test results and field test results.