Academic literature on the topic 'Surface et interfaces'
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Journal articles on the topic "Surface et interfaces"
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Zdziennicka, Anna, Katarzyna Szymczyk, and Bronisław Jańczuk. "Wettability of Quartz by Ethanol, Rhamnolipid and Triton X-165 Aqueous Solutions with Regard to Its Surface Tension." Colloids and Interfaces 7, no. 4 (December 15, 2023): 71. http://dx.doi.org/10.3390/colloids7040071.
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The wettability of quartz by different liquids and solutions plays a very important role in practical applications. Hence, the wetting behaviour of ethanol (ET), rhamnolipid (RL) and Triton X-165 (TX165) aqueous solutions with regard to the quartz surface tension was investigated. The investigations were based on the contact angle measurements of water (W), formamide (F) and diiodomethane (D) as well as ET, RL and TX165 solutions on the quartz surface. The obtained results of the contact angle for W, F and D were used for the determination of quartz surface tension as well as its components and parameters using different approaches, whereas the results obtained for the aqueous solution of ET, RL and TX165 were considered with regard to their adsorption at the quartz–air, quartz–solution and solution–air interfaces as well as the solution interactions across the quartz–solution interface. The considerations of the relations between the contact angle and adsorption of solution components at different interfaces were based on the components and parameters of the quartz surface tension. They allow us to, among other things, establish the mechanism of the adsorption of individual components of the solution at the interfaces and standard Gibbs surface free energy of this adsorption.
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Boniello, G., A. Stocco, C. Blanc, and M. Nobili. "Comment on “Brownian diffusion of a particle at an air/liquid interface: elastic (not viscous) response of the surface”." Physical Chemistry Chemical Physics 19, no. 33 (2017): 22592–93. http://dx.doi.org/10.1039/c7cp02970e.
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In a recent article Toro-Mendoza et al. considered an elastic response of an interface in order to explain the enhanced lateral drag of solid particles straddling fluid interfaces we recently measured.
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Borrel, Pascale. "Gestes de surface : Touching Reality de Thomas Hirschhorn et What Shall We Do Next? de Julien Prévieux." Interfaces, no. 40 (December 21, 2018): 55–65. http://dx.doi.org/10.4000/interfaces.601.
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Favaro, Marco. "(Invited) In Situ Photoelectron Spectroscopy Reveals the Chemical Nature of Semiconductor Surface States." ECS Meeting Abstracts MA2023-02, no. 48 (December 22, 2023): 2434. http://dx.doi.org/10.1149/ma2023-02482434mtgabs.
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The accessible photovoltage of semiconducting photoabsorbers is typically 0.5-1 V below the theoretically achievable values predicted by the Shockley-Queisser limit [1]. Although the reason for this is still not well understood, surface and interface states within the photoabsorbers energy band gap may play a crucial role as they generally induce Fermi level pinning [2]. Within the PEC community, two key elements have been identified for the maximization of the photovoltage in photoelectrodes for water splitting: (i) the passivation of surface defects which is needed to avoid Fermi level pinning, and (ii) the increase of the minority carrier concentration at the interface to improve contact selectivity and optimize carrier extraction [3,4]. To understand the role of surface defects on Fermi level pinning, detailed information on the chemical nature and electronic properties of surface states is needed. Such information is usually obtained with UHV surface science techniques such as XPS, but the photoelectrode surface under UHV conditions has little, if any, relevance to the electrified surface when immersed in the electrolyte. Moreover, recent studies have shown that semiconductor surfaces are not static, but undergo extensive structural and chemical transformations during PEC device operation [5,6]. In this talk, we will show our recent development of state-of-the-art techniques to study the structure and dynamics of semiconductor/water interfaces under practically relevant conditions [7]. The chemical nature of the electronic states for selected semiconductors prepared at the Institute for Solar Fuels has been explored using synchrotron-based resonant, ambient pressure soft and hard X-ray photoelectron spectroscopy (AP-XPS and AP-HAXPES) [6,8-11], and with in situ/operando Raman and photoluminescence spectroscopy. In particular, we will show that it is possible to study photon-induced chemical changes at solid/liquid interfaces using AP-XPS and AP-HAXPES [6,8]. We will conclude this contribution by discussing about future perspectives and technical implementations for multimodal in situ/operando investigations of photoelectrocatalytic processes. [1] M.T. Mayer. Curr. Opin. Electrochem. 2017, 2, 104. [2] A. J. Bard et al. J. Am. Chem. Soc. 1980, 102, 3671. [3] A.G. Scheuermann et al., Nat. Mater. 2016, 15, 99. [4] M. Schleuning et al., Sustainable Energy Fuels, 2022, 6, 3701. [5] F.M. Toma et al., Nat. Commun. 2016, 7, 12012. [6] M. Favaro et al., J. Phys. Chem. B 2018, 122, 801. [7] M. Favaro et al., Surf. Sci. 2021, 713, 121903. [8] M. Favaro et al., J. Phys. D: Appl. Phys. 2021, 54, 164001. [9] M. Favaro et al., J. Phys. Chem. C 2019, 123, 8347. [10] W. Wang et al., J. Am. Chem. Soc. 2022, 144, 17173. [11] P. Schnell et al., Sol. RRL 2023, 2201104.
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Zdziennicka, Anna, Edyta Rekiel, Katarzyna Szymczyk, Wojciech Zdziennicki, and Bronisław Jańczuk. "Wetting Behaviour of Water, Ethanol, Rhamnolipid, and Triton X-165 Mixture in the Polymer–Solution Drop–Air System." Molecules 28, no. 15 (August 3, 2023): 5858. http://dx.doi.org/10.3390/molecules28155858.
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Despite the fact that the wetting properties of multicomponent mixtures including the surface active compounds play a very important role in many practical applications, they are not sufficiently known. Thus, the wettability of polytetrafluoroethylene (PTFE) and poly (methyl methacrylate) (PMMA) by the water + ethanol (ET) solution of rhamnolipid (RL) with Triton X-165 (TX165) mixture was studied. The investigations involved measuring the advancing contact angles of this solution on PTFE and PMMA by varying the concentration of TX165 while maintaining a constant concentration of ET and RL. Additionally, a thermodynamic analysis was conducted to obtain the compositions and concentrations of the ET, RL, and TX165 mixtures at the different interfaces. The composition and concentration of the interface mixed layer were considered using two different approaches to the wetting process. From these considerations, it follows that, depending on the ET concentration, it is possible to form the TX165 + RL layer at the solid–water + ET mixed solvent, as well as the water + ET–air interfaces, but not at the solid–water and water–air ones. This conclusion is in accordance with the Gibbs standard free energy of adsorption of particular components of the studied mixture at the solution–air and solid–solution interfaces.
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Howe, J. M. "Quantification of order in the liquid at a solid-liquid interface by high-resolution transmission electron microscopy (HRTEM)." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 114–15. http://dx.doi.org/10.1017/s0424820100163034.
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A number of different theoretical approaches have been used to model the atomic structure and properties of solid-liquid interfaces. Most calculations indicate that ordering occurs in the first several layers of the liquid, adjacent to the crystal surface. In contrast to the numerous theoretical investigations, there have been no direct experimental observations of the atomic structure of a solid-liquid interface for comparison. Saka et al. examined solid-liquid interfaces in In and In-Sb at lattice-fringe resolution in the TEM, but their data do not reveal information about the atomic structure of the liquid phase. The purpose of this study is to determine the atomic structure of a solid-liquid interface using a highly viscous supercooled liquid, i.e., a crystal-amorphous interface.
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Vivian, Robert. "Interfaces glace-roche et érosion sous-glaciaire." Revue de géographie alpine 76, no. 2 (1988): 207–18. http://dx.doi.org/10.3406/rga.1988.2707.
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Huynh, Kenny, Michael Evan Liao, Xingxu Yan, John Tomko, Thomas Pfeifer, Viorel Dragoi, Nasser Razek, et al. "Stability of Interface Morphology and Thermal Boundary Conductance of Direct Wafer Bonded GaN|Si Heterojunction Interfaces Annealed at Growth and Annealing Temperatures." ECS Meeting Abstracts MA2023-02, no. 33 (December 22, 2023): 1605. http://dx.doi.org/10.1149/ma2023-02331605mtgabs.
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The properties of thin (~2 um) GaN templates on a silicon support substrate were studied to assess the stability of the direct wafer bonded GaN / Si interface. EVG® ComBond® equipment was used for bonding under high vacuum (~10-8 mtorr) at room temperature to remove unwanted native surface oxides [1,2]. For the bonded samples, the [1010] GaN edge was aligned parallel to the Si [110] edge. An X-ray diffraction reciprocal space map of the (004) Si and (0004) GaN revealed that there is a ~0.2° tilt between the GaN and Si layers and is simply due to the relative miscut between the two wafers. The treatment of the surfaces prior to bonding produces an amorphous region at the bonded interface that has been seen in many other bonded systems [3-5]. In the as-bonded sample, high resolution scanning transmission electron microscopy revealed a ~2 nm amorphous region on the Si side of the bonded interface, as confirmed by energy dispersive x-ray spectroscopy (EDX). Subsequent annealing was performed in an effort to recrystallize the amorphous interface. Previous work has shown that recrystallization between Si|Si wafer bonded samples occurred when annealed at 450 °C for 12 hours [3]. However, in the GaN|Si system, we found that the amorphous interface did not recrystallize when annealed under those conditions. Annealing at temperatures up to 450 °C and 120 hours showed only initial stages of interdiffusion and a stable interface. However, after annealing at 700 °C for 24 hours, high resolution EDX revealed the formation of amorphous SiN as well as the diffusion of gallium into silicon. Preliminary thermal results show that the thermal boundary conductance (TBC) of the as bonded sample is ~140 MW/(m2K). The TBC results of wafer bonded GaN|Si reported here is higher than previously reported TBC values of epitaxially grown interfaces such as GaN on Si [6], GaN on SiC [7], and GaN on diamond [8]. The TBC for the annealed interface is degraded by a factor of two compared to the as-bonded interface for the sample that was annealed at 700 °C for 24 hours. These results demonstrate that high TBC can be achieved through wafer bonding of GaN with materials such as silicon and that such interfaces are stable even up to device operation up to 300 °C. However, chemically rough interfaces formed due to high temperature annealing are detrimental to thermal transport across these interfaces. V. Dragoi, et al., ECS Trans., 86(5), 23 (2018) C. Flötgen, et al., ECS Trans., 64(5), 103 (2014) M.E. Liao, et al., ECS Trans., 86(5), 55 (2018) Y. Xu, et al., Ceramics International, 45, 6552 (2019) F. Mu, et al., Appl. Surf. Sci., 416, 1007 (2017) L. Yates, et al., ASME InterPACK (2015) J. Cho, et al., Phys. Rev. B, 89, 115301 (2014) H. Sun, et al., APL, 106(11), 111906 (2015) Figure 1
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Qu, Jianzhou, Zhou Yu, and Alexander Urban. "The Mechanism of Hydrogen Evolution Reaction at the Buried Interface of Silica-Coated Electrocatalysts." ECS Meeting Abstracts MA2023-01, no. 36 (August 28, 2023): 2104. http://dx.doi.org/10.1149/ma2023-01362104mtgabs.
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Semipermeable oxide coatings can protect electrocatalysts in harsh environments without reducing the catalytic performance (Labrador, Esposito et al. ACS Catal. 8, 2018, 1767–1778), making them attractive for direct seawater electrolysis. We recently showed that the buried SiO2/Pt interface of silica-coated platinum electrocatalysts is environment-dependent and changes with the pH value of the electrolyte and the electrode potential (Qu and Urban, ACS Appl. Mater. Interfaces 12, 2020, 52125–52135). Here, we discuss the impact of silica membrane coatings on the hydrogen evolution reaction (HER) mechanism at the interface with different transition-metal surfaces. Stable configurations of the buried SiO2/TM interface at HER conditions were determined using density-functional theory (DFT) calculations. Computed Pourbaix diagrams for different transition-metal substrates show the pH and potential dependence of reaction intermediates and the hydrogen coverage on the metal surface. Our results indicate that the HER mechanism at the buried SiO2/catalyst interfaces may involve the silica membrane. Hence, besides the protective quality of silica membranes, this also points to the possibility of designing synergistic membrane-coated electrocatalysts that surpass the bare surfaces of earth-abundant transition metals in terms of catalytic performance (stability, activity, and/or selectivity).
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Degoulange, Damien, Raj Pandya, Michael Deschamps, Dhyllan A. Skiba, Betar M. Gallant, Sylvain Gigan, Hilton B. de Aguiar, and Alexis Grimaud. "Micrometer Thick Interfaces in Aqueous Biphasic Systems for Electrochemical Devices." ECS Meeting Abstracts MA2023-01, no. 1 (August 28, 2023): 460. http://dx.doi.org/10.1149/ma2023-011460mtgabs.
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Aqueous biphasic systems (ABSs) consist of two immiscible phases composed of only one solvent (water) with the phase separation driven by solutes such as polymers, ionic liquids and salts. Such two-phase systems have proved highly relevant in recent years for applications in electrochemical devices. Indeed, highly concentrated solutions of LiTFSI, so called “Water-in-salt” battery electrolyte, were recently found to form an ABS with LiX (with X=Cl, Br, I) aqueous solutions (Dubouis et al., ACS Cent. Sci. 2019, 5, 640-643 and Dubouis et al., J. Phys. Chem. B 2021, 125, 5365-5372). These LiTFSI-LiX ABSs enable the intercalation at high potential of halides such as Cl- or Br- into graphite, in lieu of the oxidation of water or the evolution of halogenated gas, thus enabling the assembly of efficient dual-ion batteries (Yang et al., Nature 2019, 569, 245-250). Similarly, ABS have been proposed to prevent problematic crosstalk mechanisms as observed in Li-ion/sulfur batteries (Yang et al., Proc. Natl. Acad. Sci. 2017, 114, 6197-6202) or to be used to design membraneless redox flow batteries (Navalpotro et al., Adv. Sci. 2018, 5, 1800576). However for ABS to be widely implemented in electrochemical devices, the ion transfer at liquid/liquid interface is key in obtaining good (dis)charge rate and preventing self-discharge. Thus, it is crucial to first understand the structure and chemistry of these aqueous interfaces. We studied the LiTFSI-LiCl ABS first with Fourier transform infrared spectroscopy (FT-IR) and surface tension measurement to assess ion partition and surface tension respectively. Both ion partition and surface tension are found increasing as function of increasing concentration. Such trend of the surface tension is typical of a negative adsorption of ions at the liquid/liquid interface. Using high spatial resolution Raman imaging, we were able to confirm a negative adsorption of ions by assessing the ion concentration profiles at the interface between the two aqueous phases. Indeed, we found concentration profiles of water and ions to be sigmoidal which is characteristic of a negative adsorption. Strikingly, the length of the negative adsorption is ranging from 11 to 2 μm with increasing concentrations and the Raman spectra of water and TFSI anion are continuously changing along the interface from an environment with weak hydrogen bounding network and with anion aggregate to an environment similar to diluted solutions. Moreover, when changing the cation from Li+ to H+, the temperature dependence of the phase diagram is inversed, as we could show by variable temperature nuclear magnetic resonance (VT-NMR) and micro-calorimetry, but the interface is still few microns thick. Thus, we revealed a continuous change in the chemical environment between two aqueous phases at the micrometer scale, which contrast drastically with the interface between two immiscible electrolyte solutions (ITIES) such as oil-water systems where molecularly sharp, nanometer interface are found. Such difference raise question about the impact of the thickness and the chemical composition of the interface on the dynamics of ion and electron transfer at the interface, that we are studying by electrochemical measurements. Furthermore, this work paves the way to compare liquid/liquid and solid/liquid interfaces in order to understand how ion solvation affects the interfacial ion transfer and thus enable a better engineering of the electrolyte and ABSs for better electrochemical devices.
Dissertations / Theses on the topic "Surface et interfaces"
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Lenne, Quentin. "Interfaces et nano-objets fonctionnels et biomimétiques pour l'électrocatalyse." Thesis, Rennes 1, 2021. http://www.theses.fr/2021REN1S143.
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Les travaux effectués dans le cadre de cette thèse se concentrent sur la fonctionnalisation covalente de nanoparticules métalliques par une monocouche de calix[4]arènes. L’activité catalytique de ces systèmes modifiés a ensuite été étudié lors de l’activation de petites molécules ressources comme le dioxygène, le méthanol, et le dioxyde de carboneThe work presented in this manuscript is focused on the surface functionalization of metallic nanoparticles with a covalently-bound monolayers of calix[4]arenes. The catalytic activity of these modified systems was then studied for the activation of small fuel molecules such as oxygen, methanol, and carbon dioxide
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Champougny, Lorène. "Génération et rupture de films liquides minces." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS221/document.
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Source d'émerveillement et d'inspiration poétique, la beauté éphémère des films de savon recèle des questions scientifiques fondamentales, qui ont de nombreuses répercussions pour des applications allant de la formulation des shampoings à la récupération du pétrole. L'objectif de cette thèse est de comprendre comment la vie d'un film de savon, depuis sa génération jusqu'à sa rupture, dépend des propriétés physico-chimiques des tensioactifs qui le stabilisent.Dans une première partie, je m'intéresse à la génération de films savonneux verticaux, que je modélise à l'aide d'un modèle stationnaire supposant des tensioactifs insolubles. Je montre que l'épaisseur de tels films est gouvernée à la fois par la vitesse de génération et l'élasticité de surface du film. Le modèle décrit avec succès les données expérimentales pour des tensioactifs solubles, au moins dans le cas où l'adsorption est lente. Je présente également un dispositif expérimental original permettant de générer des films stabilisés par des tensioactifs insolubles, qui constituent un système modèle prometteur.Dans un second temps, j'étudie l'évolution temporelle – i.e. le drainage et la rupture – de films liquides minces en génération continue, en commençant par le cas simplifié des liquides purs. A l'aide d'une simulation non-stationnaire, je parviens à prédire le temps de vie de films d'huile silicone fonction de la vitesse de génération, qui se montre en accord quantitatif avec les expériences. Je caractérise ensuite expérimentalement le drainage des films savonneux en fonction de différents paramètres – position dans le film, vitesse de génération et humidité ambiante – et montre l'influence de la concentration en tensioactif dTAB et de l'humidité sur le temps de vie du film. Pour terminer, j'explore l'influence de la concentration en tensioactifs sur le drainage et la rupture de bulles hémisphériques flottant à la surface d'un bain savonneux, un système se rapprochant des mousses réellesThe ephemeral beauty of soap films is not only a source of wonder and poetic inspiration, but also conceals fundamental scientific questions, which are at the heart of various applications, ranging from shampoo formulation to oil recovery. This work aims at understanding how the life of a soap film, from its generation until its rupture, is affected by the physical-chemical properties of the surfactants used to stabilise it.First, I present a stationary model describing the generation of vertical soap films, under the assumption of insoluble surfactants. I show that the film thickness is controlled by both the generation velocity and the film surface elasticity. The model successfully describes experimental data for soluble surfactants, at least when adsorption is slow. I also introduce an original experimental set up for the generation of liquid films stabilised by insoluble surfactants, which are certainly a promising model system. Secondly, I study the time evolution – i.e. the drainage and rupture – of thin films pulled from a liquid bath, starting with the simplified case of pure liquids. Implementing a non-stationary simulation, I am able to predict the lifetime of silicone oil thin films as a function of the generation velocity, which I find in quantitative agreement with experimental data. I then carry out systematic experiments to characterise the drainage of soap films for various generation velocities, environmental humidities and positions in the film. I also demonstrate the influence of dTAB concentration and humidity on film lifetime. Finally, I investigate how surfactant concentration affects the drainage and break-up dynamics of hemispherical soap bubbles at the surface of a liquid pool, which is a system somewhat closer to real foams
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Bourdoucen, Hadj. "Etude des surfaces d'InP et des interfaces InP-isolant par photoluminescence." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb376033378.
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Bernardi, Sarah. "Surfaces polymères antibactériennes à base de polyionènes : synthèses et études aux interfaces en physico-chimie et biologie." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASF034.
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La contamination bactérienne des surfaces est une problématique majeure dans des domaines comme le médical ou l’agroalimentaire. Afin d’agir en amont de la formation du biofilm, nous avons choisi de réaliser des surfaces bioactives par contact pour inhiber les bactéries sans relargage d’agents actifs. L’objectif de cette thèse est de créer ces surfaces en greffant de façon covalente des polyionènes (PI) et d’en étudier les propriétés biologiques en faisant un lien avec la structure des polymères greffés.Les PI possèdent des propriétés antimicrobiennes à la fois puissantes et modulables grâce à la possibilité de modifier le ratio charge/hydrophobicité de façon contrôlée. Une gamme de PI a été synthétisée en faisant varier la longueur et la nature des segments (aliphatiques et éthers), ainsi que la masse molaire, afin d’étudier l’impact de ces trois paramètres sur l’efficacité antibactérienne et la cytotoxicité. La gamme aliphatique s’est révélée être la plus bactériostatique avec un gradient d’efficacité qui augmente avec la longueur du segment aliphatique.La gamme de PI aliphatiques a ensuite été greffée de façon covalente sur des surfaces de verre et des wafers de silicium selon une procédure séquentielle combinant un dépôt de polydopamine, une étape de polymérisation induite par des sels de diazonium et une polyaddition en surface. Les étapes de chimie ont été caractérisées en détails via diverses techniques d’analyse de surface (XPS, mesures d’énergie de surface et de potentiels zêta). Les propriétés antibactériennes des surfaces greffées ont ensuite été évaluées par des essais d’adhésion (observations des flores totales et dénombrements des flores viables cultivables). Les résultats montrent que les surfaces greffées PI présentent des propriétés antibactériennes efficaces et modulables selon la longueur du segment aliphatique, associées à un effet pro-adhésif important. Des tests de cytotoxicité ont également démontré l’absence de relargage et de toxicité des matériaux. Les chaînes greffées en surface ont aussi été étudiées par réflectivité des rayons X et des neutrons pour déterminer avec précision l’épaisseur des couches polymères et tenter d’établir un lien entre la conformation des chaînes et leur mécanisme d’action sur les bactéries.Lors de cette thèse, trois procédés ont aussi été développés afin de fonctionnaliser de façon covalente des surfaces de polyéthylène (PE), matériau principal des films alimentaires. Les PI ont d’abord été greffés sur le PE avec un procédé chimique analogue à celui du verre. Ensuite, la fonctionnalisation a été effectuée par impression après la formation d’une encre à base de PI. Enfin, dans le souci d’élaborer un procédé plus industrialisable, les PI ont été incorporés via un mélange-maître lors de l’extrusion du film de PE. Pour chacun de ces procédés, nous avons évalué la possibilité de leurs applications en caractérisant les propriétés antibactériennes et cytotoxiques des films PE modifiésBacterial contamination of surfaces is one of the most pressing concerns for the medical and the food industries. In order to act prior to the biofilm formation, we chose a preemptive strategy by creating contact-bioactive surfaces to inhibit bacteria without releasing bioactive agents. The main objective of this thesis is to prepare such surfaces by covalently grafting polyionenes (PI) and to study their biological characteristics, as well as the influence of the polymer structure on these properties.PI possess both powerful and versatile antimicrobial properties, which can be controlled by fine-tuning the charges/hydrophobic spacers ratio. A range of PI was synthesized by varying both the length and the nature of the spacers (aliphatic and ether), as well as the molecular weight, in order to evaluate the impact of these parameters on antibacterial activity and cytotoxicity. The aliphatic series was found to be more bacteriostatic, with an efficiency gradient that increases with the length of the aliphatic spacer.The aliphatic PI were then covalently grafted onto glass surfaces and silicon wafers using a sequential procedure combining polydopamine coating, diazonium salts induced polymerization and surface polyaddition. The chemical steps were characterized in detail via various surface analysis techniques (XPS, energy and zeta potential measurements). Antibacterial properties of the grafted surfaces were then evaluated by adhesion tests (total flora observations and enumerations of viable cultivable flora). PI-grafted surfaces were shown to display effective and versatile antibacterial properties, associated with a pro-adhesive effect. Cytotoxicity tests also demonstrated the absence of release and the non-toxicity of these materials. X-ray and neutron reflectivity experiments were performed on PI grafted chains to determine the thickness of polymers layers and to establish a link between the chains conformation and their mechanism of action towards bacteria.During this thesis, three procedures were developed to covalently functionalize polyethylene (PE) surfaces, the main component of food packaging. Firstly, PI were grafted onto PE with a chemical process similar to the one performed on glass. Secondly, a PI based ink was prepared to functionalize the PE film with an ink-jet printing process. Lastly, in order to develop a more industrializable process, PI were incorporated in bulk during the extrusion of PE films. For each procedure, we evaluated the possibility of their applications by characterizing their antimicrobial and cytotoxicity properties
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Taleb, Mandana. "Phénomènes aux interfaces des isolants : mesure et simulation." Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1550/.
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Les matériaux polymères sont largement utilisés en tant qu'isolants dans les domaines du génie électrique, de l'électronique de puissance et de la microélectronique. Ces diélectriques sont principalement en contact avec d'autres composants: avec des semi-conducteurs et des métaux dans les câbles haute tension, avec des substrats et d'autres diélectriques dans les systèmes multicouches. Ces interfaces sont omniprésentes, et contribuent à l'injection et l'accumulation de charges d'espace dans les diélectriques solides. D'autre part, au cours de leur vie, ils sont soumis à de nombreuses contraintes, de température, de champ. . . Ces contraintes peuvent conduire à la dégradation prématurée et à la rupture diélectrique du matériau par une distorsion du champ électrique, et conduire au dysfonctionnement du système. Des études antérieures, expérimentales et de simulations, ont montré l'importance des interfaces sur la génération de charges à l'intérieur du diélectrique, mais les approches théoriques comme la loi d'injection Schottky ne fournissent pas une description adéquate pour des courants expérimentaux. Aucune loi d'injection de charge ne permet actuellement de traduire ce qui est observé expérimentalement au niveau de la simulation. Cependant les recherches récentes montrent que les états de surface qui se forment à l'interface métal/isolant jouent un rôle important sur le comportement des diélectriques. L'injection de charges est principalement affectée par la nature du contact et des états de surface. Les états de surface sont principalement dus à des défauts chimiques, à savoir, des impuretés, des additifs et des antioxydants, ou physique comme la rugosité de surface, etc. Écouter Lire phonétiquement Dictionnaire - Afficher le dictionnaire abréviation Virginie. L'enjeu de ce travail est de comprendre les phénomènes en jeu à une interface métal/isolant, afin de les modéliser correctement. Ce travail est basé sur une approche duale modélisation et expérience. L'isolant retenu est ici est le polyéthylène basse densité (LDPE). Dans un premier temps, nous avons caractérisé expérimentalement des interfaces métal/isolant, grâce notamment aux mesures disponibles (mesures de charge d'espace, de courant de conduction, de luminescence, de profilomètrie. . . ). Dans un seconde temps, nous avons développé un modèle numérique capable de prendre en compte les états de surface. L'approche est originale, puisque l'étude porte sur l'injection et le transport de charges en tenant compte d'une distribution exponentielle des états d'énergie à l'interfaceDue to their thermal, electrical or mechanical properties, solid organic dielectrics are more and more used in electronic, electrical and microelectronic domains. However, these dielectrics are mainly used in systems where they are in contact with other components: with semi-conducting screens in High Voltage cables, with substrates and other dielectrics in multi-layer systems, with micro or nano-particles of organic or inorganic materials. Interfaces exist in such systems and contribute to the space charge accumulation in solid dielectrics. This charge build-up can lead to dielectric breakdown, meaning the failure of the system. The major problem remains the physical description of these interfaces, as it is known that injection of charges from the interfaces is determinant in the charge generation and transport. Indeed, theoretical approaches like the Schottky injection law do not provide an adequate description of experimental currents in wide band gap insulations. Recently, surface states at the metal/organic interface were suggested as the source of additional energetic disorder, localized near the interface. Localized states at the interface are known to have a large impact on charge injection and extraction so a better understanding of the interface mechanisms is then necessary in order to develop an alternative model for charge injection. The aim of this work is to better understand the impact of the nature of the metal and of the surface topology on the charge generation at a metal/ dielectric interface. This work is based on a dual approach modeling and experience. The insulation used is here is the low density polyethylene (LDPE). First, we characterized experimentally metal / insulator interfaces thanks to the available measures (measures of space charge, current conduction, luminescence, profilometry. . . ). In a second step, we developed a numerical model capable of taking into account the surface states. The approach is original, because the study focuses on charge injection and transport with an exponential distribution of energy states at the interface
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Bouali, Bachir. "Contribution à l'étude des phénomènes de mouillage pour la caractérisation des surfaces et interfaces : maîtrise de la physico-chimie et de la morphologie des surfaces pour régler les propriétés fonctionnelles des interfaces : applications industrielles." Lyon 1, 1998. http://www.theses.fr/1998LYO10132.
Full textAbstract:
La maitrise du comportement d'une surface est un element important qui intervient dans divers processus technologiques et biologiques tels que la lubrification, l'usure, l'adhesion, la glisse, la detergence, l'adsorption des proteines l'etude des phenomenes a l'interface est determinante pour l'optimisation de ces processus. Le mouillage peut etre considere comme un outil d'investigation pour etudier les proprietes d'une telle interface et notamment les proprietes d'usage caracteristiques de chaque domaine d'application. Dans le present travail, nous avons exploite differentes approches de la mouillabilite aussi bien pour la description du liquide mouillant que du solide mouille. Dans un premier temps, nous nous sommes attaches a decrire, les interactions moleculaires a l'interface liquide - solide et a evaluer la pertinence les differents modeles proposes pour estimer l'energie de surface du solide. Nous avons ensuite examine les relations entre la topographie de la surface solide et les angles de contact a l'aide d'une approche pluridisciplinaire originale faisant intervenir les aspects morphologiques et physico-chimiques de cette surface. La partie liquide de l'interface a ete prise en compte en etudiant le comportement au mouillage de differents liquides sur des surfaces solides connues et bien caracterisees. Enfin, nous avons etudie l'hysteresis de mouillage a partir du comportement dynamique de gouttes de liquide decrochant sur une surface inclinable. L'ensemble des travaux exposes constitue une contribution a la caracterisation de l'interface liquide-solide et propose une methodologie generale d'approche de cette interface.
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Prado, Gaël. "Propriétés de jets granulaires denses et mesure d'une tension de surface granulaire." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14727/document.
Full textAbstract:
Les milieux granulaires présentent une grande diversité de comportements physiques que l'on peut relier aux différents états "conventionnels" de la matière : solide, liquide ou gaz. Les travaux décrits dans ce manuscrit se concentrent sur les écoulements granulaires denses présentant de nombreuses analogies avec les liquides moléculaires. Les expériences présentées dans ce manuscrit sont réalisées en utilisant des jets granulaires s'écoulant d'un réservoir, dans l'air et sous l'effet de la gravité. Quelques propriétés de tels jets sont étudiées, notamment l'évolution du diamètre au cours de la propagation. L'évolution de cette grandeur permet une description des jets granulaires comme des fluides incompressibles dans une certaine gamme de diamètres de sortie D et de diamètres des particules d, résumés en une grandeur réduite : le rapport d'aspect D/d. Lorsque ce dernier est inférieur à une grandeur critique proche de 15, les jets granulaires cessent de se comporter comme des liquides incompressibles et sont alors décrits comme des gaz en expansion.La transition entre les deux régimes d'écoulements est expliquée par un modèle faisant intervenir l'équilibre entre la température granulaire et sa dissipation par l'inélasticité des collisions entre les billes constituant le milieu granulaire. En utilisant les mesures de la température granulaire accessibles à la paroi dans le réservoir, ce modèle permet d'obtenir les profils de température et de fraction volumique du milieu en fonction du rapport d'aspect ainsi que leurs valeurs moyennes, présentant un bon accord avec les mesures de la fraction volumique en sortie du réservoir.Dans le régime "liquide" des jets granulaires mis en évidence ici, une tension de surface effective est mesurée par l'étude d'une instabilité similaire à celle de Rayleigh-Plateau. En soumettant le jet à une oscillation verticale apparaît une modulation du diamètre du jet dont il est possible d'étudier l'évolution au cours du temps. La mesure des taux de croissance des modes instables excités permet d'établir la relation de dispersion et d'obtenir une tension de surface effective dans les jets granulaires. Il est montré que cette tension de surface effective décroit lorsque la taille des particules augmente, décroit lorsque la pression de l'air ambiant diminue et augmente avec la distance de propagation.Le mécanisme proposé pour expliquer l'origine de cette tension de surface effective est l'interaction entre le jet granulaire et l'air ambiant. Les profils de vitesse de l'air entraîné par le jet sont mesurés pour différentes diamètres de particules, différentes pression ambiantes et différentes distances de propagation. L'entraînement de l'air et les profils de vitesses sont utilisés pour définir certaines forces s'exerçant sur les billes et construire une tension de surface effective : l'ordre de grandeur de cette tension de surface est incompatible avec les mesures réalisées précédemment. Une mesure de la pression de l'air à l'intérieur du jet granulaire permet d'obtenir une force exercée par la perméation de l'air à travers les pores du jet dont l'ordre de grandeur est correctGranular media exhibit a broad range of behaviours that can be related to the common states of matter: solid, liquid and gaseous. The experiments described in this thesis focus on dense granular flows ad their analogies with molecular liquid flows.The work presented focuses on granular material flowing from a reservoir, in ambient air under the effect of gravity. Some properties of such jets are presented, among them the evolution of the diameter of the jet along propagation. This evolution allows one to describe granular jets as incompressible liquid jets for a certain range of parameters D (exit diameter) and d (beads diameter). When using a reduced variable D/d (the aspect ratio), a transition appears close to a critical value (approx. 15) below which the granular jet exhibit a gas-like behaviour.This transition is explained using a model supposing balance between the heat flux (from the granular temperature imposed at the wall of the reservoir) and its dissipation through inelastic collisions between the beads in the granular medium. This model allows one to compute the temperature and volume fraction profiles as well as their mean values which are in good agreement with the experimental measurements (volume fraction at the exit).In the "liquid" regime defined previously, an effective surface tension is measured by studying the unstable modes of a Rayleigh-Plateau like instability. This instability is obtained by imposing a vertical oscillation on the jet which induces a diametrical modulation whose evolution is measured. Measurements of the growth rates of these unstable modes leads to the dispersion relation $\omega (kr_{0})$ and to an effective granular surface tension. This surface tension shows a diminution when the beads' size increases, a diminution when the air pressure is reduced and a growth along propagation.The proposed mechanism explaining this effective surface tension is the interaction between the granular jet and the surrounding air. Air velocity profiles are measured for different beads diameters, different air pressures and different distances below the outlet. Using these velocity profiles, various forces exerted on the beads are calculated, leading to a surface tension whose order of magnitude is lower than the one measured through the Rayleigh-Plateau instability. The right order of magnitude can be obtained by considering the air permeation through the pores on the surface the jet and the force exerted along the surface of said pores
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Kempf, Didier. "Caractérisation mécanique des surfaces et interfaces aux échelles micrométrique et nanométrique : étude des processus d’oxydation et de piqûration." Dijon, 2007. http://www.theses.fr/2007DIJOS061.
Full textAbstract:
Prédire la durée de vie des alliages métalliques nécessite de comprendre les rôles des paramètres mécaniques, physiques et chimiques dans l’amorçage et la propagation des piqûres. L’objectif de ce travail est de développer de nouvelles méthodes d’analyse en mécanique aux échelles microscopiques pour cartographier les gradients de déformation et les propriétés mécaniques à la surface des alliages métalliques, en prenant en compte leur microstructure complexe. Ces méthodes seront appliquées à l’étude des processus d’oxydation et de piqûration et des critères mécano-électrochimique seront proposés. Dans un premier temps, les gradients de déformation liés à l’application d’un chargement mécanique dans le domaine plastique sont cartographiés aux échelles microscopiques à l’aide des micro-jauges métalliques. Les relations entre la microstructure, les déformations plastiques et les mécanismes de piqûration sont ensuite étudiées. Dans un deuxième temps, l’influence de la microstructure sur les mécanismes d’oxydation des aciers inoxydables duplex a été quantifiée à l’échelle microscopique. Des réseaux de plots non métalliques ont été utilisés pour cartographier les déformations à l’interface entre le substrat et le film d’oxydes sur des éprouvettes oxydées thermiquement. La technique de spectroscopie Auger locale a été utilisée pour quantifier les épaisseurs et les compositions des films d’oxydes. Afin d’identifier les lois de comportement des alliages métalliques à l’échelle des grains, des tests de nano-indentation avec plusieurs géométries d’indenteurs ont été effectués et analysés selon des modèles issus de la littérature. En couplant la nano-indentation à la diffraction des rayons X et à la simulation numérique par éléments finis du test de nano-indentation, nous avons adapté les modèles existants pour déterminer les propriétés élasto-plastiques du matériau. Un premier modèle numérique par éléments finis prédictif a alors été développéTo predict the service time of metallic alloys, a multi-disciplinary approach is essential. The roles of mechanical, physical and chemical parameters on pit initiation will be studied. The aim of this present work is to develop new mechanical methodologies at the microscopic scale to quantify the strain gradients and the mechanical properties of the alloy surfaces. These specific methodologies will be applied to the study of the influence of the microstructure and the mechanics in the oxidation and pit initiation process. First, strain gradients induced by a mechanical solicitation will be quantified at the microscopic scale using the grating method (with metallic dots of 70 nm in diameter). A study on the influence of the heterogeneous strain fields and microstructure on pit initiation is proposed. Second, the influence of microstructure and strain mapping on the oxidation process of duplex stainless steel at the microscopic scale was studied. Grating method with non-metallic dots was used to map the heterogeneous strain field at the interface between the substrate and the thermal-oxide film. Local Auger spectroscopy was used to determine the thickness and the compositions of oxide films. At last, nano-indentation tests have been done to identify the behaviour laws of the duplex stainless steel at the grain scale. Many tests have been done with different indenter geometries in order to apply the analytical models available in the literature. The elasto-plastic parameters have been determined coupling the nano-indentation test with X-ray diffraction and finite element simulation of the nano-indentation test. Then, the grain rheologies founded have been inserted in a predictive finite element model of the duplex stainless steel behavior
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Corradini, Valdis. "Auto-organisation de nanofils de Césium sur la surface (110) d'InAs et densité d'états d'un gaz d'électrons bidimensionnel à la surface de semiconducteurs." Paris 6, 2001. http://www.theses.fr/2001PA066409.
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Taleb, Mandana. "PHENOMENES AUX INTERFACES DES ISOLANTS : MESURE ET SIMULATION." Phd thesis, Université Paul Sabatier - Toulouse III, 2011. http://tel.archives-ouvertes.fr/tel-00670594.
Full textAbstract:
Les matériaux polymères sont largement utilisés en tant qu'isolants dans les domaines du génie électrique, de l'électronique de puissance et de la microélectronique. Ces diélectriques sont principalement en contact avec d'autres composants: avec des semi-conducteurs et des métaux dans les câbles haute tension, avec des substrats et d'autres diélectriques dans les systèmes multicouches. Ces interfaces sont omniprésentes, et contribuent à l'injection et l'accumulation de charges d'espace dans les diélectriques solides. D'autre part, au cours de leur vie, ils sont soumis à de nombreuses contraintes, de température, de champ... Ces contraintes peuvent conduire à la dégradation prématurée et à la rupture diélectrique du matériau par une distorsion du champ électrique, et conduire au dysfonctionnement du système. Des études antérieures, expérimentales et de simulations, ont montré l'importance des interfaces sur la génération de charges à l'intérieur du diélectrique, mais les approches théoriques comme la loi d'injection Schottky ne fournissent pas une description adéquate pour des courants expérimentaux. Cependant les recherches récentes montrent que les états de surface qui se forment à l'interface métal/isolant jouent un rôle important sur le comportement des diélectriques. L'injection de charges est principalement affectée par la nature du contact et des états de surface. L'enjeu de ce travail est de comprendre les phénomènes en jeu à une interface métal/isolant, afin de les modéliser correctement. Ce travail est basé sur une approche duale modélisation et expérience. L'isolant retenu est ici est le polyéthylène basse densité (LDPE). Dans un premier temps, nous avons caractérisé expérimentalement des interfaces métal/isolant. Dans un seconde temps, nous avons développé un modèle numérique capable de prendre en compte les états de surface. L'approche est originale, puisque l'étude porte sur l'injection et le transport de charges en tenant compte d'une distribution exponentielle des états d'énergie à l'interface.
Books on the topic "Surface et interfaces"
1
Butt, Hans-Jürgen. Surface and interfacial forces. Weinheim: Wiley-VCH, 2010.
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2
Journées de géographie tropicale (11th 2005 Schoelcher, Martinique). Les interfaces: Ruptures, transitions et mutations : XIes Journées de géographie tropicale du Comité national français de géographie ... Université des Antilles et de la Guyane, Schoelcher, 7-10 novembre 2005. Pessac: Presses universitaires de Bordeaux, 2008.
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3
F, Pagney Bénito-Espinal, ed. Les interfaces: Ruptures, transitions et mutations : XIes Journées de géographie tropicale du Comité national français de géographie ... Université des Antilles et de la Guyane, Schoelcher, 7-10 novembre 2005. Pessac: Presses universitaires de Bordeaux, 2008.
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4
Colloque de Métallurgie (45th 2002 Saclay, France). 45e Colloque de Métallurgie de l'INSTN: Surfaces, interfaces et rupture : CEA Saclay/INSTN, 25-27 juin 2002. Les Ulis, France: EDP Sciences, 2003.
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5
1935-, Baszkin Adam, and Norde Willem 1944-, eds. Physical chemistry of biological interfaces. New York: M. Dekker, 2000.
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6
G, Compton R., and Hamnett A, eds. New techniques for the study of electrodes and their reactions. Amsterdam: Elsevier, 1989.
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7
Lyklema, J. Fundamentals of Interface and Colloid Science, Volume III: Liquid-Fluid Interfaces (Fundamentals of Interface and Colloid Science). Academic Press, 2000.
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Lyklema, J. Fundamentals of Interface and Colloid Science, Volume III: Liquid-Fluid Interfaces (Fundamentals of Interface and Colloid Science). Academic Press, 2000.
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9
Butt, Hans-Jürgen, and Michael Kappl. Surface and Interfacial Forces. Wiley & Sons, Incorporated, John, 2009.
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10
Butt, Hans-Jürgen, and Michael Kappl. Surface and Interfacial Forces. Wiley & Sons, Incorporated, John, 2010.
Find full textBook chapters on the topic "Surface et interfaces"
1
Shvartsburg, A. B. "Non-linear interfaces in optical systems." In Non-Linear Pulses in Integrated and Waveguide Optics, 104–50. Oxford University PressOxford, 1993. http://dx.doi.org/10.1093/oso/9780198563587.003.0002.
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Abstract A non-linear interface is an important optical element for spatial and temporal modulation of wave beams. This element consists of the interface between two dielectric materials, one of which has an intensitydependent refractive index. The interest in non-linear surface wave phenomena is twofold: firstly, these phenomena can provide subsurface localization of powerful wave fields. On the other hand the reflection of light from the electrically-driven interface is an effective tool for tuning the parameters of reflected light waves. The latter effect results in optically controlled tuning of wave refraction also. Puting aside the numerous problems connected with generation of new harmonics at the non-linear boundary, which was the subject of classical research work at the outset of the laser era (Bloembergen et al. 1962), we shall analyse the novel possibilities of wave governing beams using power-dependent reflection effects.
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KOMABA, Shinichi, and Kei KUBOTA. "NaMO2 lamellaires à l’électrode positive." In Les batteries Na-ion, 9–59. ISTE Group, 2021. http://dx.doi.org/10.51926/iste.9013.ch1.
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Ce chapitre présente les développements réalisés sur les oxydes lamellaires de métaux de transition 3d utilisés à l’électrode positive de batteries Na-ion, en s’appuyant principalement sur les recherches menées par ses auteurs depuis 2003. Les performances électrochimiques, les transitions de phase mises en jeu au cours des cycles de charge et de décharge, la chimie de surface aux interfaces électrode-électrolyte, les facteurs clés influençant les performances des batteries et les perspectives d'avenir y sont discutées.
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Koukia, Spiridoula, Maria Rigou, and Spiros Sirmakessis. "Content Personalization for Mobile Interfaces." In Mobile Computing, 1064–68. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-054-7.ch087.
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The contribution of context information to content management is of great importance. The increase of storage capacity in mobile devices gives users the possibility to maintain large amounts of content to their phones. As a result, this amount of content is increasing at a high rate. Users are able to store a huge variety of content such as contacts, text messages, ring tones, logos, calendar events, and textual notes. Furthermore, the development of novel applications has created new types of content, which include images, videos, MMS (multi-media messaging), e-mail, music, play lists, audio clips, bookmarks, news and weather, chat, niche information services, travel and entertainment information, driving instructions, banking, and shopping (Schilit & Theimer, 1994; Schilit, Adams, & Want, 1994; Brown, 1996; Brown, Bovey, & Chen, 1997). The fact that users should be able to store the content on their mobile phone and find the content they need without much effort results in the requirement of managing the content by organizing and annotating it. The purpose of information management is to aid users by offering a safe and easy way of retrieving the relevant content automatically, to minimize their effort and maximize their benefit (Sorvari et al., 2004). The increasing amount of stored content in mobile devices and the limitations of physical mobile phone user interfaces introduce a usability challenge in content management. The physical mobile phone user interface will not change considerably. The physical display sizes will not increase since in the mobile devices the display already covers a large part of the surface area. Text input speed will not change much, as keyboard-based text input methods have been the most efficient way to reduce slowness. While information is necessary for many applications, the human brain is limited in terms of how much information it can process at one time. The problem of information management is more complex in mobile environments (Campbell & Tarasewich, 2004).
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Kelly, M. J. "III-V Semiconductor Homojunctions And Heterojunctions." In Low-Dimensional Semiconductors, 26–60. Oxford University PressOxford, 1995. http://dx.doi.org/10.1093/oso/9780198517818.003.0002.
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Abstract In the Introduction, we referred to the hundredfold reduction in the lateral feature size of transistors in integrated circuits over the period from the late 1960s to the present day. This reduction has been accompanied by a similar scaling down of vertical dimensions of the devices, i.e. in the thicknesses of the individual layers (see Dennard et al. (1974) and Chapter 21 below). Indeed, if one takes the p-n-p bipolar transistor from its earliest fabrication to the present day, new technologies that have allowed the ever sharper internal interfaces of devices to be achieved have appeared at intervals of approximately 10 years. The original transistors were made in the 1950s by alloying in the species to make a p-type layer in a host n-type material, and then overalloying to produce a new n-type layer near the surface. This technique is exceptionally crude by today’s standards. The interface between then- and p-type material is uncontrolled over thicknesses of micrometres. Furthermore, the interface follows the melt front of the alloying species.
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Koukia, Spiridoula, Maria Rigou, and Spiros Sirmakessis. "Content Personalization for Mobile Interfaces." In Human Computer Interaction, 992–96. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-87828-991-9.ch061.
Full textAbstract:
The contribution of context information to content management is of great importance. The increase of storage capacity in mobile devices gives users the possibility to maintain large amounts of content to their phones. As a result, this amount of content is increasing at a high rate. Users are able to store a huge variety of content such as contacts, text messages, ring tones, logos, calendar events, and textual notes. Furthermore, the development of novel applications has created new types of content, which include images, videos, MMS (multi-media messaging), e-mail, music, play lists, audio clips, bookmarks, news and weather, chat, niche information services, travel and entertainment information, driving instructions, banking, and shopping (Schilit & Theimer, 1994; Schilit, Adams, & Want, 1994; Brown, 1996; Brown, Bovey, & Chen, 1997). The fact that users should be able to store the content on their mobile phone and find the content they need without much effort results in the requirement of managing the content by organizing and annotating it. The purpose of information management is to aid users by offering a safe and easy way of retrieving the relevant content automatically, to minimize their effort and maximize their benefit (Sorvari et al., 2004). The increasing amount of stored content in mobile devices and the limitations of physical mobile phone user interfaces introduce a usability challenge in content management. The physical mobile phone user interface will not change considerably. The physical display sizes will not increase since in the mobile devices the display already covers a large part of the surface area. Text input speed will not change much, as keyboard-based text input methods have been the most efficient way to reduce slowness. While information is necessary for many applications, the human brain is limited in terms of how much information it can process at one time. The problem of information management is more complex in mobile environments (Campbell & Tarasewich, 2004). One way to reduce information overload and enhance content management is through the use of context metadata. Context metadata is information that describes the context in which a content item was created or received and can be used to aid users in searching, retrieving, and organizing the relevant content automatically. Context is any information that can be used to characterize the situation of an entity. An entity is a person, place, or object that is considered relevant to the interaction between a user and an application, including the user and the applications themselves (Dey, 2001). Some types of context are the physical context, such as time, location, and date; the social context, such as social group, friends, work, and home; and the mental context, which includes users’ activities and feelings (Ryan, Pascoe, & Morse, 1997; Dey, Abowd, & Wood, 1998; Lucas, 2001). By organizing and annotating the content, we develop a new way of managing it, while content management features are created to face efficiently the usability challenge. Context metadata helps the user find the content he needs by enabling single and multi-criteria searches (e.g., find photos taken in Paris last year), example-based searches (e.g., find all the video clips recorded in the same location as the selected video clip), and automatic content organization for efficient browsing (e.g., location-based content view, where the content is arranged hierarchically based on the content capture location and information about the hierarchical relationships of different locations).
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Streit, Anthony, Bruno Guillaume, Bertrand Girardin, Lucas Terrei, Anthony Collin, and Alexis Marchand. "Fire propagation from surface to canopy on ornamental species under wind in laboratory conditions." In Advances in Forest Fire Research 2022, 582–92. Imprensa da Universidade de Coimbra, 2022. http://dx.doi.org/10.14195/978-989-26-2298-9_90.
Full textAbstract:
Fires in wildland-urban interfaces (WUIs) are resulting from intertwined physical processes at different scales: landscape, settlement, parcel, building and material(Vacca et al., 2020) and are causing growing damage worldwide in context of climate change and large urban sprawl. The significant damage caused by these fires requires effective reinforcement of the resistance of structures and parcels against exposure to fire. Recent methodologies (Vacca et al., 2020; Benichou et al., 2021; Maranghides et al., 2022) have emphasised the need to look at these objectives by considering the spatial relationships between fuels, exposures and building resistance, in the perspective of a fire propagating in WUI according to so-called “fire pathwaysâ€. At parcel scale the fire pathways often involve ornamental vegetation, that highly raises the damaging potential of the wildfire, this vegetation being at short distance to the structures and having size comparable to building size. Horizontal and vertical discontinuities in this vegetation do largely impact the exposure (Cohen, 2008) and installing such discontinuities is becoming part of the protection regulation against wildfires in different countries (Maranghides et al., 2022). While the impact of embers has been extensively studied in the Insurance Institute for Business and Home Safety (IBHS) facilities (Manzello and Suzuki, 2014; Suzuki and Manzello, 2020), the effect of the fuel discontinuities on the reduction of thermal attack when approaching the building has been poorly addressed. This study aims at simulating in laboratory conditions a moving fire front pushed by wind and propagating from the surface to a canopy of ornamental vegetation, with fuel discontinuities. The experimental setup is composed of a fire lit in a surface excelsior fuelbed, propagating to a nearby vertical ornamental structure (excelsior and cypress) exposed to controlled high wind exposure (up to 10 m/s). The work is completed by a comparison of numerical modelling between the WFDS and FDS models. The first steps of this study are shown here, namely on zero-wind surface fire propagation, showing a coherent sensitivity of the rate of spread to fuelbed width and fuelbed load, and showing the ability of WFDS and FDS to reasonably reproduce this rate of spread. The ability of FDS to propagate to an isolated vertical tree with the same modelling processes is also well established.
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Ellis, Stephen R. "Origins and Elements of Virtual Environments." In Virtual Environments and Advanced Interface Design. Oxford University Press, 1995. http://dx.doi.org/10.1093/oso/9780195075557.003.0007.
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Virtual environments created through computer graphics are communications media (Licklider et al., 1978). Like other media, they have both physical and abstract components. Paper, for example, is a medium for communication. The paper is itself one possible physical embodiment of the abstraction of a two-dimensional surface onto which marks may be made. The corresponding abstraction for head-coupled, virtual image, stereoscopic displays that synthesize a coordinated sensory experience is an environment. These so-called “virtual reality” media have only recently caught the international public imagination (Pollack, 1989; D’Arcy, 1990; Stewart, 1991; Brehde, 1991), but they have arisen from continuous development in several technical and non-technical areas during the past 25 years (Brooks Jr., 1988; Ellis, 1990; Ellis, et al., 1991, 1993; Kalawsky, 1993). A well designed computer interface affords the user an efficient and effortless flow of information to and from the device with which he interacts. When users are given sufficient control over the pattern of this interaction, they themselves can evolve efficient interaction strategies that match the coding of their communications to the characteristics of their communication channel (Zipf, 1949; Mandelbrot, 1982; Ellis and Hitchcock, 1986; Grudin and Norman, 1991). But successful interface design should strive to reduce this adaptation period by analysis of the user’s task and performance limitations. This analysis requires understanding of the operative design metaphor for the interface in question. The dominant interaction metaphor for the computer interface changed in the 1980’s. Modern graphical interfaces, like those first developed at Xerox PARC (Smith et al., 1982) and used for the Apple Macintosh, have transformed the “conversational” interaction from one in which users “talked” to their computers to one in which they “acted out” their commands in a “desk-top” display. This so called desk-top metaphor provides the users with an illusion of an environment in which they enact wishes by manipulating symbols on a computer screen. Virtual environment displays represent a three-dimensional generalization of the two-dimensional “desk-top” metaphor. These synthetic environments may be experienced either from egocentric or exocentric viewpoints. That is to say, the users may appear to actually be in the environment or see themselves represented as a “You are here” symbol (Levine, 1984) which they can control.
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Bond, A. M. "Illustration of the principles of voltammetry at solid-electrode-solvent (electrolyte) interfaces when redox active microparticles are adhered to an electrode surface." In Broadening Electrochemical Horizons, 334–440. Oxford University PressOxford, 2002. http://dx.doi.org/10.1093/oso/9780198504788.003.0005.
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Abstract In Chapter 2, the basic theory describing the voltammetry associated with oxidation or reduction of an ideal thin layer was considered. Unfortunately, such ideally behaved thin films are rarely encountered in practice and cannot even be prepared for many redox active systems. Thus, concepts based on these principles have limited applicability. As an alternative to preparation of films modified electrodes, a general form of attachment of solids to electrode surfaces has arisen from the work of Scholz et al. [1–4].
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"16 Surfaces, interfaces et membranes." In Théorie statistique des champs, 539–78. EDP Sciences, 2022. http://dx.doi.org/10.1051/978-2-7598-2218-8.c008.
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"Chapitre 8 : Surfaces et interfaces." In Thermodynamique des matériaux, 299–332. EDP Sciences, 2020. http://dx.doi.org/10.1051/978-2-7598-0928-8-010.
Full textConference papers on the topic "Surface et interfaces"
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Rosenwaks, Y., B. R. Thacker, A. J. Nozik, R. J. Ellingson, K. C. Burr, and C. L. Tang. "Femtosecond Carrier Dynamics at InP/Liquid Interfaces in the Presence of Electric Fields." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1994. http://dx.doi.org/10.1364/up.1994.thd.17.
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Recently there has been considerable interest in studying photogenerated carrier dynamics in semiconductors under the influence of electric fields1. This is a process of critical importance in recombination kinetics and electron transfer processes at semiconductor interfaces. At semiconductor-liquid interfaces, very large electric fields (typically 105 to 106 volts/cm) exist in the semiconductor close to its surface because of the formation of a space charge layer (SCL)2. Externally-applied potentials will drop across the SCL to increase or decrease the space charge fields (SCFs) and the surface band bending-VB. Under bandgap illumination the SCFs are reduced because of screening by the photogenerated majority carriers, but strong residual SCFs are ubiquitous across any semiconductor liquid interface. It is expected that these SCFs may have a crucial role in electron transfer (ET) processes at semiconductor electrodes.
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Li, Shi-Ming, and Danesh K. Tafti. "A Mean-Field Free-Energy Lattice Boltzmann Model for Liquid-Vapor Interfaces." In ASME 2006 2nd Joint U.S.-European Fluids Engineering Summer Meeting Collocated With the 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/fedsm2006-98021.
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A nonlocal pressure equation is proposed for liquid-vapor interfaces based on mean-field theory. The new nonlocal pressure equation is shown to be a generalized form of the nonlocal pressure equation of the van der Waals theory or the “square-gradient theory”. The proposed nonlocal pressure is implemented in the mean-field free-energy lattice Boltzmann method (LBM) proposed by Zhang et al (2004). The modified LBM is applied to simulate equilibrium interface properties and the interface dynamics of capillary waves. Computed results are validated with Maxwell constructions of liquid-vapor coexistence densities, theoretical relationship of variation of surface tension with temperature, theoretical planar interface density profiles, and the dispersion relation between frequency and wave number describing the dynamics of capillary waves. It is shown that the modified LBM gives very good agreement with the theories. In addition, preliminary calculations of phase transition and binary droplet coalescence are also presented.
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Lin, Shih-Chun, and John Hong. "Anomalous diffraction of a grazing laser beam by a dielectric interface: experimental observation." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1988. http://dx.doi.org/10.1364/oam.1988.wi5.
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In 1977, Kolomeev et al.1 reported observation of anomalous diffusion of a laser beam when incident at a grazing angle to one surface from the 90° vertex and perpendicular to the other surface of a glass right-angle prism. They also provided a theory for the phenomenon. The diffracted light showed a distinct oscillatory distribution, followed the critical angle of total internal reflection with good directivity, and was due to the interface only. Recently we reexamined the phenomenon and thought that the diffraction effect could serve as the basis for designing optical switches, especially in conjunction with nonlaser optical interfaces. Using a CCD linear detector array, we measured the intensity patterns of the transmitted and the diffracted beams of the following light sources: (a) a single-line He–Ne laser; (a) a dual-line Ar+laser; and (c) a broadband xenon-arc lamp, at both glass–air and water–air interfaces. The optical beams, both inside and outside the prism, were visualized. The fact that the diffraction is due to the interface alone was firmly established by perturbing the interface with films of alcohol, contacting dielectric wedges and metal surfaces, and oscillating wires. All these new results are presented. Comparison to the theory is given, and application of this effect to optical switching is described.
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Gupta, Vijay, and Allen Yu. "Characterizing Adhesion of Thermal Barrier Coatings." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0691.
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Abstract A previously developed technology of laser-generated stress pulses has been adapted to measure the tensile strengths of interfaces between composite thermal barrier coatings of alumina and zirconia, and steel substrates. In the basic technique developed previously (Gupta et al., 1994), a compressive stress pulse is generated on the back side of the substrate disc by exfoliating a constrained metallic film via the impingement of a Nd:YAG laser pulse. This compressive stress pulse propagates through the substrate and reflects into a tensile wave from the free surface of the coating that is deposited on its front surface. The returning tensile pulse pries off the interface if its amplitude is sufficiently high. The interface stress is determined by recording the coating’s free-surface velocity by using a laser displacement interferometer. Because of the short rise time of the stress pulse, an interfacial region of approximately 70 to 150 micrometers is uniformly stressed. This results in the failure of the weakest link in the region which is spanned by the coating, interface and the substrate material. In addition, such a short pulse is able to invoke a rather local response from the interface such that minute structural and chemical changes are directly reflected in the measured strengths.
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Ishii, Eiji, and Taisuke Sugii. "Spreading-Droplet Simulation With Surface Tension Model Using Inter-Particle Force in Particle Method." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62542.
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Predicting the spreading behavior of droplets on a wall is important for designing micro/nano devices used for reagent dispensation in micro-electro-mechanical systems, printing processes of ink-jet printers, and condensation of droplets on a wall during spray forming in atomizers. Particle methods are useful for simulating the behavior of many droplets generated by micro/nano devices in practical computational time; the motion of each droplet is simulated using a group of particles, and no particles are assigned in the gas region if interactions between the droplets and gas are weak. Furthermore, liquid-gas interfaces obtained from the particle method remain sharp by using the Lagrangian description. However, conventional surface tension models used in the particle methods are used for predicting the static contact angle at a three-phase interface, not for predicting the dynamic contact angle. The dynamic contact angle defines the shape of a spreading droplet on a wall. We previously developed a surface tension model using inter-particle force in the particle method; the static contact angle of droplets on the wall was verified at various contact angles, and the heights of droplets agreed well with those obtained theoretically. In this study, we applied our surface tension model to the simulation of a spreading droplet on a wall. The simulated dynamic contact angles for some Weber numbers were compared with those measured by Šikalo et al, and they agreed well. Our surface tension model was useful for simulating droplet motion under static and dynamic conditions.
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Wen, Xiao, and Decheng Wan. "Numerical Simulation of Three-Layer-Liquid Sloshing by Multiphase MPS Method." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-78387.
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In the present study, three-layer-liquid sloshing in a rigid tank is simulated based on the newly developed multiphase MPS method. Firstly, the multiphase MPS method is introduced in detail, including the basic particle interaction models and the special interface treatments employed to extend single phase MPS solver to multiphase flows simulations. The new multiphase MPS method treats the multifluid system as the multi-density and multi-viscosity fluid, thus only a single set of equations needs to be solved for all phases. Besides, extra density smoothing technique, interparticle viscosity model and surface tension model are included in the present method for interface particles. The new multiphase MPS method is then applied to simulate three-layer-liquid sloshing in a rigid tank and verified through comparison with the experiment conducted by Molin et al. [1]. The predicted motion of interfaces by the present method shows a good agreement with the experimental data and other numerical results.
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Desai, Anand, James Geer, and Bahgat Sammakia. "Experimental Measurements of Temperature Distribution in Three Dimensional Stacked Package." In ASME 2007 InterPACK Conference collocated with the ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ipack2007-33045.
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This paper presents the results of an experimental study of steady state heat conduction in a three dimensional stack package. The temperatures are measured at different interfaces within the stacked package. Delphi devices are used in the experiment which enables controlled power input and surface temperature of the devices. The experiment is carried out for three different boundary conditions on the package. The power input in varied to study its effects. A numerical model is created to compare to the experimental results. The results are also compared with the analytical solution presented in Desai et al [5] and Geer et al [6]. The results indicate that the experimental, numerical and analytical solutions follow the same trend. The agreement between the experimental and numerical results improves when the lateral losses are taken into account.
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Li, Yuan, Bojun Li, Lianqi Sheng, Erdong Yao, Kun Zhang, Guolin Yu, and Fujian Zhou. "Comparative Study on Enhanced Oil Recovery Effect of Amphiphilic Nanomaterials - Experiment and Mechanism Investigation." In 56th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2022. http://dx.doi.org/10.56952/arma-2022-2045.
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ABSTRACT: Due to the transcendental property of nanoparticle, nanoparticle fluid flooding becomes one of the enhanced oil recovery (EOR) technique, which had played a significant role in tight oil exploitation in the worldwide scale recent years. In particular, the amphiphilic nanomaterials can greatly increase the oil recovery. To provide some guidance in selecting nanomaterials for flooding, 3 kinds of amphiphilic nanomaterials, including silicon dioxide (SiO2), graphene oxide (GO) and molybdenum disulfide (MoS2), are chosen to serve as object of the study. In lab, the physical properties were systematically characterized and flooding was conducted. Further, the morphology character of nanomaterials was placed extra emphasis and the mechanisms of EOR were also studied. The purpose was to find the link between the morphology of nanomaterials and EOR. Flooding experiment revealed that MoS2 were able to enhance the oil recovery by approximately 11%, which were better that of the others. From the above, it can be inferred that spherical materials have a "point-to-surface" contact at multiphase interfaces, while sheet materials can achieve a "surface-to-surface" contact with a higher interfacial activity. In addition, the film-climbing characteristics of amphiphilic nanomaterials were found in the experiment, which may be one of the potential reasons for enhanced oil recovery. 1. INTRODUCTION Most of the world’s oil fields have experienced primary and secondary oil recovery, with severe declines in well production and increases in water content. Combined with unfavourable conditions such as low reservoir permeability, about 50% or more of the crude oil cannot be successfully recovered (Alija et al, 2018). Chemical drive is a commonly used method to enhance recovery and is widely used in China, but with the gradual expansion of unconventional reservoir development, the main application of chemical drive has shifted to low-permeability and ultra-low-porosity reservoirs. Due to the small pore size and large specific surface area of low-permeability and ultra-low-permeability reservoirs, they have unfavourable factors such as high start-up pressure gradients and insufficient formation energy, and the development of these reservoirs is mainly based on water injection, resulting in problems such as "no injection, no recovery" in low-permeability and ultra-low-permeability reservoirs (LI Weicai et al, 2011; DOU Hong en et al, 2014; LI Xiangfang en et al, 2020). This has become one of the current issues of concern in terms of EOR.
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Cai, Guanglei, Hui Yang, and Qi Zhao. "Time-Lapse Measurement of P-Wave Velocities Under the Freeze-Thaw Condition in Various Rocks." In 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0441.
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ABSTRACT Global warming issues have led to pronounced cryospheric changes in mountainous areas and cold regions. Freeze-thaw weathering can alter the properties of rock masses and permafrost soils, drastically changing local environmental and geological conditions. So far, although many in-situ and laboratory tests have investigated the variation of mechanical and hydraulic properties of rock under changing temperatures, the effect of temperature variation on the rock seismic properties (e.g., elastic wave velocity, wave amplitude, wave frequency, and wave attenuation) is still insufficiently studied. In this study, we developed a laboratory setup for time-lapse measurement of ultrasonic wave propagation across rocks under freeze-thaw conditions. The P-wave velocities under changing temperature from −20 °C to 20 °C were continuously recorded for four types of rocks (i.e., granite, marble, sandstone, and gabbro) under both dry and saturated conditions. The results demonstrate that the P-wave velocity of all saturated rocks drops significantly when the temperature is above 0 °C. Particularly, saturated sandstone was observed to have the greatest drop in wave amplitude, probably owing to the relatively high water content due to its high porosity. Also, we observe a hysteresis of wave velocity related to the rocks’ temperature gradient during the freeze-thaw cycles. These findings provide new insights into rock dynamic responses related to temperature changes in the cryosphere and cold regions. INTRODUCTION Global warming has led to extensive and enduring climate anomalies worldwide, including extremely high air temperatures in summer, fierce seasonal floods, devastating rainfalls, and so forth (Goswami, 2009; Masson-Delmotte, 2022; Rovinaru et al., 2022). The temperature rise also causes the melt of the polar glaciers, permafrost, and mountainous ice in cold regions, negatively influencing the slope stability and infrastructure performance for a long term and resulting in rock-mud flow events and uneven settlement of ground surface (Krautblatter et al., 2013; Mamot et al., 2021; Pläsken et al., 2020). Since most polar grounds and alpine mountain areas are underlain by permafrost, which is thermally defined as the lithospheric material (except glaciers) that remains below or equal to 0 °C for at least two consecutive years (Tarnocai, 1989), they are considered particularly sensitive to climate change (Nogués-Bravo et al., 2007; Schiavon & Zecchin, 2007). The degrading permafrost due to increasing temperature can trigger the freeze-thaw weathering effects and therefore affect the thermal, hydraulic, and mechanical properties of the rock masses, soil bodies, and their interfaces resulting in a drastic change in local environmental and geological conditions (Gruber & Haeberli, 2007; Krautblatter et al., 2012). The changes in the cryosphere will consequently increase the occurrence and magnitude of alpine rock hazards such as rock slope landslide, abrupt rockfall activities, and rock-based infrastructure damage resulting from slow and large rock deformation (Haeberli et al., 2017; Stoffel & Huggel, 2012).
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Ghoshal, Anindya, Michael J. Walock, Muthuvel Murugan, Clara Mock, Luis Bravo, Marc Pepi, Andy Nieto, et al. "Governing Parameters Influencing CMAS Adhesion and Infiltration Into Environmental/Thermal Barrier Coatings in Gas Turbine Engines." In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-92000.
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Abstract Sand particulate ingestion into modern gas turbine engines for fixed wing and vertical lift aircraft is a significant challenge for both military and civilian missions. ARL as part of a DoD funded Laboratory University Collaborative Initiative (LUCI) and Vannevar Bush Fellowship at UCSD are investigating the governing parameters that primarily influences the CMAS adhesion kinetics and infiltration on the standard Yttria Stabilized Zirconia (YSZ) as part of metallic single crystal Nickel superalloys TBC and SiC/SiC CMC T/EBCs. Current research shows various parameters including CMAS viscosity, porosity, adhesion strength, contact angle (wettability factor), geological factors affecting sand formation, coating and structural substrate roughness and surface temperature, internal flow Reynolds number, temperature, pressure, Mach number, boundary layer and bleed air, coating process (columnar vs splat morphology), tortuosity factor et al affects the CMAS adhesion and infiltration. This paper is a summary of our current research to identify and study the governing parameters that affects the CMAS formation, adhesion and infiltration and the underlying interfaces between CMAS and T/EBC, bond coat and the structural substrate. This work is aligned with Army Modernization Priority Future Vertical Lift and PEO Aviation Advanced Turbine Engine (ATE) Program.