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Auswahl der wissenschaftlichen Literatur zum Thema „Surface et interfaces“
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Zeitschriftenartikel zum Thema "Surface et interfaces"
1
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 (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.
2
Cronin, Stephen B. "(Invited) In Situ spectroscopy of Electrocatalytic and Photocatalytic Interfaces." ECS Meeting Abstracts MA2024-01, no. 35 (2024): 1980. http://dx.doi.org/10.1149/ma2024-01351980mtgabs.
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We explore various aspects of electrochemistry and photoelectrochemistry using in situ spectroscopy of electrode (metal) and photoelectrode (semiconductor) interfaces in situ under electrochemical working conditions. These spectroscopies include sum frequency generation (SFG), transient reflectance/absorption spectroscopy (TAS/TRS), and surface enhanced Raman spectroscopy (SERS). Using surface enhanced Raman scattering (SERS) spectroscopy, we monitor local electric fields using Stark-shifts of nitrile-functionalized silicon photoelectrodes.6 We also report several spectroscopic methods for monitoring local electric fields (within the double layer), local pH,1 photo-induced surface potential and charge transfer2 at electrode surfaces using surface reporter molecules. The Figure below illustrates two surface reporter molecules for determining the local pH, local surface potential, and charge transfer at electrode and photoelectrode surfaces. We also measured the stacking dependence and Resonant interlayer excitation of monolayer WSe2/MoSe2 heterostructures for photocatalytic energy conversion.3 Using sum frequency generation (SFG) spectroscopy, we measure the voltage dependence of the orientation of D2O molecules at a graphene electrode surface, which is related back to the “stiffness of the ensemble”.4 Using transient absorption spectroscopy (TAS), we measure the lifetime of hot electrons photoexcited in plasmon resonant nanostructures.5 Using transient reflectance spectroscopy (TRS), we measure the photoexcited carrier dynamics in a GaP/TiO2 photoelectrode, as well as the electrostatic field dynamics at this semiconductor-liquid interfaces in situ under various electrochemical potentials.6 Here, the electrostatic fields at the surface of the semiconductor are measured via Franz−Keldysh oscillations (FKO). These spectra reveal that the nanoscale TiO2 protection layer enhances the built-in field and charge separation performance of GaP photoelectrodes.7 1 Wang, Y.Y., et al., Measuring Local pKa and pH Using Surface Enhanced Raman Spectroscopy of 4‐Mercaptobenzoic Acid. Langmuir, DOI:10.1021/acs.langmuir.3c02073 (2023). 2 Li, R., et al., SERS Detection of Charge Transfer at Electrochemical Interfaces Using Surface-Bound Ferrocene. The Journal of Physical Chemistry C, 127, 14263 (2023). 3 Chen, J., et al., Stacking Independence and Resonant Interlayer Excitation of Monolayer WSe2/MoSe2 Heterostructures for Photocatalytic Energy Conversion. ACS Applied Nano Materials, DOI:10.1021/acsanm.9b01898 (2020). 4 Montenegro, A., et al., Field-Dependent Orientation and Free Energy of D2O at an Electrode Surface Observed via SFG Spectroscopy. Journal of Physical Chemistry C, 126, 20831 (2022). 5 Wang, Y., et al., In Situ Investigation of Ultrafast Dynamics of Hot Electron-Driven Photocatalysis in Plasmon-Resonant Grating Structures. Journal of the American Chemical Society, 144, 3517 (2022). 6 Xu, Z.H., et al., Direct In Situ Measurement of Quantum Efficiencies of Charge Separation and Proton Reduction at TiO2-Protected GaP Photocathodes. Journal of the American Chemical Society, 2860-2869 (2023). 7 Wang, Y. and S.B. Cronin, Performance Enhancement of TiO2-encapsulated Photoelectrodes Based on III–V Compound Semiconductors, in Ultrathin Oxide Layers for Solar and Electrocatalytic Systems. 2022, Royal Society of Chemistry. p. 103-134. Figure 1
3
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.
4
Strmcnik, Dusan, Dzevad K. Kozlica, Milena Martins, et al. "(Invited) Electrocatalysis at Modified Electrochemical Interfaces." ECS Meeting Abstracts MA2024-02, no. 61 (2024): 4116. https://doi.org/10.1149/ma2024-02614116mtgabs.
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Electrochemical energy storage and conversion technologies, which include fuel cells, electrolyzers, batteries, photoelectrochemical devices are at the forefront of the transition to a sustainable future. Although they have all been in use for more than half a century, they are far from reaching their full potential as defined by the laws of thermodynamics. Their performance rests almost entirely on the electrochemical interface - the boundary between the electronic conductor (electrode) and the ionic conductor (electrolyte). The desire of both phases to reduce the surface energy as well as the appearance of electrochemical potential across the interface can manifest itself as the formation of unique (near)surface atom arrangements (e.g. surface relaxation or reconstruction), as significant differences in electrode composition close to the surface (e.g. segregation profile), via substrate-adsorbate covalent and non-covalent interactions, via formation of a passive film as well as ordering of solvent and/or electrolyte molecules several nm away from the surface. This extremely complex and sensitive "interfacial bridge", is a consequence of inherent incompatibility of two materials, brought into contact, and is very hard to control. However, to control it means to control the energy efficiency, power density, durability and safety – the most important metrics of any energy conversion and storage device. In this presentation we will discuss, how the chemical nature of non-covalently and covalently [1,2] adsorbed species as well as thicker passive films and their morphology at the electrochemical interface affect the individual terms of the common rate equation [1], including the free energy of adsorbed intermediates and adsorbed spectators, mass transport, availability of active sites and electronic and ionic resistivity for common electrocatalytic reactions in acid and alkaline aqueous as well as in non-aqueous media on a plethora of metal electrodes (Pt, Ir, Au, Ni, Cu) as well as carbon. We will draw parallels between HER, OER, HOR and ORR in electrolyzers [1], fuel cells [2] and Li-ion batteries [3,4]. The interphase properties will be discussed through the lens of deviations of modified electrode properties from its intrinsic properties. Examples of artificially modified interfaces [5,6] will be given to demonstrate our ability to tailor their activity, stability and selectivity to our liking. [1] Strmcnik, D. Lopes, P.P., Genorio, B., et al. Design principles for hydrogen evolution reaction catalyst materials, Nano Energy, 29, 29-36 (2016) [2] Strmcnik, D., Uchimura, M., Wang, C. et al. Improving the hydrogen oxidation reaction rate by promotion of hydroxyl adsorption. Nature Chem 5, 300–306 (2013) [3] Strmcnik, D., Castelli, I.E., Connell, J.G. et al. Electrocatalytic transformation of HF impurity to H2 and LiF in lithium-ion batteries. Nat Catal 1, 255–262 (2018) [4] Martins, M., Haering, D., Connell, J.G., et al. Role of Catalytic Conversions of Ethylene Carbonate, Water, and HF in Forming the Solid-Electrolyte Interphase of Li-Ion BatteriesACS Catalysis 13, 9289-9301 (2023) [5] Zorko, M. Martins, P.F.B.D., Connell, J.G. et al. Improved Rate for the Oxygen Reduction Reaction in a Sulfuric Acid Electrolyte using a Pt(111) Surface Modified with Melamine, ACS Applied Materials & Interfaces 13, 3369-3376 (2021) [6] Strmcnik, D., Escudero-Escribano, M., Kodama, K. et al. Enhanced electrocatalysis of the oxygen reduction reaction based on patterning of platinum surfaces with cyanide. Nature Chem 2, 880–885 (2010)
5
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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6
Favaro, Marco. "(Invited) In Situ Photoelectron Spectroscopy Reveals the Chemical Nature of Semiconductor Surface States." ECS Meeting Abstracts MA2024-01, no. 35 (2024): 1981. http://dx.doi.org/10.1149/ma2024-01351981mtgabs.
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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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Favaro, Marco. "(Invited) In Situ Photoelectron Spectroscopy Reveals the Chemical Nature of Semiconductor Surface States." ECS Meeting Abstracts MA2023-02, no. 48 (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.
8
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 (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.
9
Fraysse, Kilian, Lixu Huang, Hua Li, et al. "On the Parasitic Surface Adsorption of Pyrrolidinium and Phosphonium-Based Ionic Liquid Preventing Accurate Differential Capacitance Measurements." ECS Meeting Abstracts MA2024-02, no. 57 (2024): 3870. https://doi.org/10.1149/ma2024-02573870mtgabs.
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Ionic Liquids (ILs) have received a substantial interest from the scientific community over the past few decades1, in particular, because of their possible use as electrolytes for battery technology. This wide excitement stems from their known thermal stability and non-volatile nature2 (as opposed to more traditional organic carbonate-based electrolytes) which has led the study of IL to fall under the category of green chemistry3. In a similar fashion to aqueous-based electrolytes, whose bulk properties are fundamentally different from their properties near charged interfaces (giving rise to an Electrical Double Layer, EDL), ILs and IL-based electrolytes also exhibit a distinct interfacial structuring near charged surfaces consisting of alternating layers of cations and anions4 extending into the liquid over several nanometers5. This interfacial structuring (i.e., EDL) initially formed at the electrode/electrolyte interface defines the charge transfer mechanism6. It is also believed to play a critical role in the formation of the Solid Electrolyte Interphase (SEI)7,8. The latter, via its morphological, mechanical and chemical properties directly governs the performance of the battery9. Electrochemical Impedance Spectroscopy (EIS) is an attractive technique for the indirect study of the EDL at charged interfaces, via the so-called differential capacitance measurement. The latter giving an indication of the ionic density near the interface10. Differential capacitance measurements are, however, difficult to interpret and compare, because there is no real consensus as to how the measurement needs to be performed. To add to the difficulty, some ionic liquids are known to display a hysteresis process, inducing measurement variabilities. In this study, we propose to investigate the structure of the EDL of pure IL (trimethyl isobutyl phosphonium bis(fluorosulfonyl)imide, P111i4FSI and N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)imide, C3mpyrFSI) as well as IL-based electrolytes composed of 42mol% of NaFSI in C3mpyrFSI and/or P111i4FSI using both a differential capacitance and AFM approach. Using a well-established method for the measurement of the differential capacitance in IL and IL-based electrolytes, we show that all the studied systems display important hysteresis properties (in particular, the pyrrolidinium-based ones). Via a series of differential capacitance as well as AFM experiments, we further demonstrate that the hysteresis is a result of adsorption processes on the surface of the electrode. This parasitic adsorption leads inaccuracies in traditional differential capacitance measurements. We therefore propose an alternative method for the measurement of the differential capacitance which allows to minimize the impact of adsorption. This new understanding of differential capacitance measurements has important methodological implications. By providing guidelines for accurately probing the differential capacitance of ILs and IL-based electrolytes, in particular, pyrrolidinium and phosphonium-based ones via a single, reliable method, this report may well help pave the way to easier comparisons and interpretations. J.P. Hallett et al., Chem. Rev. 2011, 111, 3508-3576. S. Zhang et al., ACS Appl. Mater. Interfaces 2021, 13, 53904-53914. K. Paduszynski et al., J. Chem. Inf. Model. 2014, 54, 1311-1324. J.M. Black et al., ACS Appl. Mater. Interfaces 2017, 9, 40949-40958. R. Hayes et al., Chem. Rev. 2015, 115, 6357-6426. D. Rakov et al., Chem. Mater. 2021, 34, 165-177. Q. Wu et al., J. Am. Chem. Soc. 2023, 145, 2473-2484. D.S. Silvester et al., J. Phys. Chem. C 2021, 125, 13707-13720. Y. Zhou et al., Nat. Nanotechnol. 2020, 15, 224-230. J.M. Klein et al., Phys. Chem. Chem. Phys. 2019, 21, 3712-3720. Figure 1
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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.
Dissertationen zum Thema "Surface et interfaces"
1
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 carbone<br>The 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
2
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 réelles<br>The 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 modifiés<br>Bacterial 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'interface<br>Due 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.
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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.
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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 correct<br>Granular 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.
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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 développé<br>To 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.
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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. 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.
Bücher zum Thema "Surface et interfaces"
1
Butt, Hans-Jürgen. Surface and interfacial forces. 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. Presses universitaires de Bordeaux, 2008.
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3
G, Compton R., and Hamnett A, eds. New techniques for the study of electrodes and their reactions. Elsevier, 1989.
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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. EDP Sciences, 2003.
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5
1935-, Baszkin Adam, and Norde Willem 1944-, eds. Physical chemistry of biological interfaces. M. Dekker, 2000.
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6
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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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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8
Butt, Hans-Jürgen, and Michael Kappl. Surface and Interfacial Forces. Wiley & Sons, Incorporated, John, 2009.
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9
Butt, Hans-Jürgen, and Michael Kappl. Surface and Interfacial Forces. Wiley & Sons, Incorporated, John, 2010.
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10
Butt, Hans-Jürgen, and Michael Kappl. Surface and Interfacial Forces. Wiley & Sons, Incorporated, John, 2018.
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1
Wu, Jianjun, Jian Li, Yuanzheng Zhao, and Yu Zhang. "Numerical Simulation of the Laser Ablation Process of PTFE Propellant." In Numerical Simulation of Pulsed Plasma Thruster. Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-7958-1_3.
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AbstractTo avoid the ablation lag problem of pulsed plasma thrusters (PPTs), researchers have used laser ablation as a replacement for spark plug ignition and proposed a new laser-sustained PPT (LS-PPT) (Arai in AIAA J 17:634–640, 1979; Zhang in Theoretical, experimental, and simulation study of laser-sustained pulsed plasma thrusters. Graduate School of National University of Defense Technology, Changsha, 2014) Arai et al. (ISAS Rept 544, 1976; AIAA J 15(11):1656–1657, 1977), Arai and Karashimat (Aiaa J 2(2):572–579, 1979) studied the transient ablation problem of the PTFE ablative thermal protection layer on a blunt-body spacecraft during reentry under intense radiative and convective environments. They also elucidated the surface recession of the PTFE layer and the internal temperature and time evolution pattern of the molten layer. Finally, they constructed a phase change ablation model of a one-dimensional (1D) bilayer PTFE (Clark in J Heat Trans T ASME 94: 347–354, 1972), considering the transmittance of the crystalline and molten layers as well as the bulk absorption of radiant energy by the bilayer structure. Stechmann (Numerical analysis of transient Teflon ablation in pulsed plasma thrusters. Worcester Polytechnic Insitute, p 354, 2007) slightly modified the ablation model proposed by Arai et al. and used a volume fraction method to capture the phase change interface between the crystalline and molten layers and obtained the ablation pattern along the surface of the PTFE propellant in the PPT.
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Shvartsburg, A. B. "Non-linear interfaces in optical systems." In Non-Linear Pulses in Integrated and Waveguide Optics. 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. 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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Hebeler G.L. and Frost J.D. "Interface based in situ soil classification." In Characterization and Behavior of Interfaces. IOS Press, 2010. https://doi.org/10.3233/978-1-60750-491-7-91.
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A main objective in all geotechnical site investigations is to determine the type, extent, and properties of the geologic materials in as much detail as possible within the constraints of the given site conditions and project budget. Cone penetrometers (CPTs), specifically piezocones (CPTUs), offer a site investigation tool that can effectively identify the behavioral type and extent of tested stratigraphy, and provide unparalleled profiling ability, with CPTU response times typically sufficiently fast to identify very thin layers (&lt; 5 mm) (Lunne et al., 1997). Accurate geostratification and classification are paramount to successful geotechnical engineering practice, as the soil layering and classification often serve as the basis for all subsequent analyses and calculations. The values of CPT data are functions of a number of fundamental soil characteristics, and as such, the variations in measured response can be used to identify both the layering and properties of tested soils. The interface behavior of soils is known to vary as both a function of soil type and the contacting interface properties. Most notably soil &ndash; continuum interface response is known to be primarily affected by the angle of internal friction of the soil and the surface roughness of the counterface material. The multi friction attachment devices recently developed at Georgia Tech have the ability to provide in situ measurements of interface behavior across the full range of typical surface roughness properties encountered in geotechnical engineering and for all soil conditions amenable to penetrometer investigations. This paper analyzes the friction data obtained for the various geologic conditions tested to date, to investigate whether the use of the multi friction attachment (MFA) and multi piezo friction attachment (MPFA) can provide data allowing for improved in situ soil classification through the use of fundamental soil-interface behavior concepts.
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Koukia, Spiridoula, Maria Rigou, and Spiros Sirmakessis. "Content Personalization for Mobile Interfaces." In Mobile Computing. 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. 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. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-87828-991-9.ch061.
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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). 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. Imprensa da Universidade de Coimbra, 2022. http://dx.doi.org/10.14195/978-989-26-2298-9_90.
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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. 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].
Konferenzberichte zum Thema "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. 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. 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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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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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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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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Weng, X. "Analysis of Shear Slip Ahead of Hydraulic Fracture Along a Frictional Interface Not Aligned with Principal Stresses and Conditions for Secondary Branching." In 58th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2024. http://dx.doi.org/10.56952/arma-2024-0256.
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ABSTRACT: Stress field at the trailing edge of the shear-slip zone ahead of a hydraulic fracture (HF) traveling along a natural fracture (NF) not aligned with maximum horizontal stress is studied in the context of its potential for inducing secondary fracture branching from the NF. The size and amount of shear-slip and the stress parallel to the NF wall are computed. Localized tensile stress occurs at the trailing edge of the shear-slip zone, with a logarithmic singularity which is similar to the elastic solution for a half-space subjected to a surface shear traction. The induced tensile stress may lead to a small surface crack being nucleated and HF branching away from NF. From the stress solution, maximum stress intensity factor K1max at the tip of a prospective crack and its corresponding length are estimated. If K1max is greater than fracture toughness, a crack can be nucleated. Example cases show that crack initiation strongly depends on HF length, NF angle, coefficient of friction and stress anisotropy. Crack initiation occurs only when HF reaches a sufficient length since the shear-slip zone length is proportional to HF length, which in turn affects K1 at the crack tip. 1. INTRODUCTION Interaction of a hydraulic fracture (HF) and a weak interface, which can be an open or poorly cemented natural fracture (NF) or a bedding plane and is hereafter referred to as a NF in general, plays an important role in fracture stimulation of unconventional formations. When a HF intersects a NF, the interaction may result in HF crossing NF directly or with an offset (also referred to as a step-over), or being arrested by the NF. In the latter case, HF can dilate and propagate along the NF if fluid pressure exceeds the normal stress on the NF. The crossing/arrest behavior at the moment of fracture intersection has been extensively studied. Various empirical/theoretical criteria had been investigated and proposed (Warpinski and Teufel (1987), Blanton (1982, 1986), Renshaw and Pollard (1995), Gu and Weng (2010), Gu et al. (2011), Chuprakov et al. (2013)) and been incorporated in complex fracture network models (Weng et al. (2011), Weng et al. (2016)). The understanding of a HF crossing a weak interface with an offset is somewhat limited. Cooke and Underwood (2001) studied numerically the stress parallel to the interface on the opposite wall ahead of the tip of a vertical HF approaching a weak bedding plane. They attributed the initiation of offsetting fracture to tensile peaks in the stress on both sides of the intersection point due to local interfacial opening and slippage near the intersection point for "moderate-strength" interfaces. These peaks move closer together and their magnitude increases as the distance between the fracture tip and the interface becomes small, and they occur in the shear-slip region ahead of the opening segment. Fracture offset has also been studied numerically by Thiercelin and Makkhyu (2007), and Chuprakov et al. (2010).
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Li, Yuan, Bojun Li, Lianqi Sheng, et al. "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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Zhang, N., Z. Li, Y. Zhao, J. Wu, S. Wang, and X. Wang. "Advancements in CT Three-Dimensional Reconstruction of Rock Samples." In International Geomechanics Conference. ARMA, 2024. https://doi.org/10.56952/igs-2024-0295.
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ABSTRACT: Understanding the internal discontinuities, joints, and fissures within rock samples is crucial across multiple engineering fields, including geotechnical engineering and energy exploration. Computed tomography (CT) technology, with its non-destructive and high-resolution capabilities, has become indispensable for studying rock internal structures, overcoming the limitations of traditional methods such as mercury intrusion porosimetry, scanning electron microscopy, and nuclear magnetic resonance. This paper reviews the recent progress in the application of CT for three-dimensional (3D) reconstruction in rock mechanics. The CT technology's operational principles, encompassing X-ray penetration, signal conversion by detectors, and computer-aided reconstruction, are outlined. The discussion focuses on critical steps like image preprocessing, threshold segmentation, and 3D reconstruction, underscoring the selection of appropriate segmentation thresholds for precision. The integration of CT with laboratory investigations of rock permeability and numerical simulations is also explored. Despite advancements, challenges persist in aligning sample size with scanning resolution, threshold determination, and the development of 3D reconstruction algorithms. Future research should consider applying CT in geological CO2 utilization and storage and merging CT with other analytical techniques to broaden its scope and enhance geological research methods. 1. INTRODUCTION The mechanical properties, damages and seepage characteristics of rocks are critical research areas in fields such as oil and gas extraction, geology, geotechnical engineering and coal mining. Currently, most studies on these characteristics are based on basic assumptions that the spatial distribution of rock structures and physical-mechanical properties is homogeneous, layer-wise homogeneous or artificially given as statistically non-homogeneous distributions(Yue, 2022; Wang et al.,2021). However, rocks are composed of different mineral particles bonded or embedded together, and the prolonged sedimentation and geological processes lead to numerous discontinuous and irregular joints, fractures, and sedimentary interfaces within the rocks. Research into the heterogeneous and discontinuous characteristics of rock mechanics must first obtain the heterogeneous and discontinuous structure inside the rocks. With the advancement and development of testing equipment, as well as the requirements for the precision and imaging methods of pore and fracture observations, techniques such as mercury intrusion porosimetry (MIP) (Turturro et al.,2022), scanning electron microscopy (SEM) (Ma et al.,2022), nuclear magnetic resonance (NMR) (Cai et al.,2018), and X-ray diffraction (XRD) (Zhang et al.,2023) have gradually been applied to pore characterization studies, as detailed in Table 1. MIP is a destructive experiment and tends to underestimate the content of large pores due to its limitation on the maximum pore radius it can measure (Tang et al.,2021; Chu et al.,2022; Zhu et al.,2016). The pressure measured reflects the diameter of the pore entrance rather than the pore itself. SEM can observe the mineral occurrence form, crystal form, surface morphology, and composition, but it requires pre-treatments like gold coating and sectioning, and the observation range is very small, limiting the structural analysis to a small sample area, making it difficult to provide detailed information on the porosity and connectivity of large mineral bodies (Dehestani et al.,2020;Zhang et al.,2014;Du et al.2019). NMR, as a non-destructive testing method, is widely used to characterize pore structures with high measurement accuracy, but it is challenging to reconstruct the 3D pore structure and to obtain further information on other minerals in coal-rock bodies (Luo et al.,2022;Zhao et al.,2019).