Dissertations / Theses on the topic 'Capillary condensation'
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Pozzato, Alessandro. "Capillary condensation in nanostructured surfaces." Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3426628.
Full textIl tema di questa tesi è lo studio dello studio dei fenomeni di condensazione capillare in superfici nano strutturate. La motivazione principale a sostegno di questo lavoro è la verifica di recenti teorie che descrivono il riempimento di capillari chiusi ad una estremità. Le isoterme di assorbimento dell’argon sono state misurate a temperature leggermente superiori al suo punto triplo con l’uso di una micro bilancia torsionale. Un elemento chiave per questo tipo di esperimenti è la disponibilità di superfici strutturate con una distribuzione periodica di elementi regolari (ad esempio canali rettangolari o cavità cilindriche). Per costruire substrati di questo genere, è stato necessario sviluppare una metodologia fabbricativa innovativa, basata su tecniche di litografia avanzata. La metodologia ottimizzata si basa sulla cosiddetta nanoimprint lithography (NIL), su etching in ambiente liquido (uso di soluzioni BOE per l’etching di ossido di silicio) ed etching con uso di plasma gassosi in macchine di tipo ICP (Inductively Coupled Plasma). Con il nostro processo siamo in grado di strutturare superfici con area di estensione fino a 1 cm2 con distribuzione regolare di canali a sezione rettangolare o cavità di forma emisferica, entrambi con dimensioni caratteristiche nel range dei nanometri. In particolare abbiamo realizzato canali di due differenti larghezze (90 e 200 nm) e profondità caratteristica variabile tra 0:5 e 2 µm. Isoterme di adsorbimento misurate con questo tipo di campioni mostrano transizioni nette e reversibili correlabili con la condensazione capillare di argon liquido. La posizione di queste transizioni varia col variare della larghezza dei canali: canali più larghi evidenziano una transizione più vicina alla condensazione liquido-vapore in fase bulk. L’analisi quantitativa di questi risultati, in termini della classica equazione di Kelvin, mostra previsioni in buon accordo con la caratterizzazione diretta dei campioni tramite immagini al SEM. La definizione precisa del profilo della parete del canale è ancora sotto analisi per la conferma delle previsioni teoriche. La fabbricazione dei campioni è stata condotta presso il laboratorio nazionale TASC-INFM in Trieste sotto la supervisione del Dr. Massimo Tormen, mentre la misurazione delle isoterme di adsorbimento è stata condotta nel laboratorio del Prof. Giampaolo Mistura all’Università di Padova
Hiratsuka, Tatsumasa. "Kinetic Nature of Capillary Condensation in Nanopores." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225638.
Full textZAMORA, ROBERT RONALD MAGUINA. "INFLUENCE OF CAPILLARY CONDENSATION IN NANOSCALE FRICTION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2005. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=6648@1.
Full textNesta tese, apresentamos um procedimento utilizado para a calibração do fotodetector e dos cantileveres utilizados em nosso AFM para a medida de força lateral. Desenvolvemos um código em Matlab para o controle do microscópio que permitiu a realização do estudo da influência da força normal na fricção. Também foi desenvolvido um segundo código em Matlab para a medida automatizada da adesão. Apresentamos e discutimos a influência da energia livre superficial na fricção e adesão de várias superfícies. Neste trabalho um estudo da influência da condensação capilar na forca lateral foi estudado para superfícies hidrofílicas, e hidrofóbicas. Encontramos que as nano asperezas podem realizar contatos singulares descritos pelo modelo de Hertz ou múltiplos contatos de acordo com o modelo de Greenwood. O tipo de contato entre as nano asperezas pode ser controlado através da hidrofobicidade e da umidade relativa no ambiente de medida. É verificado que os meniscos formados entre ponta e superfície influenciam a força lateral, através do aumento da força normal e também através da energia gasta pela ponta para arrastar ou deformar o capilar durante seu deslocamento sobre a superfície. O efeito da cinética de condensação capilar da água sobre a fricção foi também estudado. É mostrado que a molhabilidade é determinante para a definição dos mecanismos da dissipação de energia entre as nanoasperezas. Apresentamos também a influência da hidrofobicidade superficial no coeficiente de atrito. A correlação observada entre o ângulo de contato e o coeficiente de atrito reforça a importância da cinética da condensação capilar nos processos de fricção que ocorre na escala de nanômetros.
In this work, the procedures developed to the calibration of the AFM photodetector and cantilevers for lateral force measurements in our AFM is presented. A Matlab code that controls the microscope allows the study of the influence of the normal force on the lateral one. A second Matlab code was developed in order to study the adhesion forces in an automated way. We present and discuss the influence of the surface free energy on the friction and adhesion forces. In this work, the lateral forces were measured at hydrophilic and hydrophobic surfaces. It was observed that the nano asperities may form single asperity contacts described by the Hertz model as well as multi-asperity type of contacts described by the Greenwood model. The nanoasperity contact may be controlled by the wettability and ambient relative humidity. It is seen that the capillar formed between the tip and the surface influences the tip-surface normal force and the friction forces due to the dissipation of energy caused by the drag or brake of the capillar meniscous. The effect of capillary condensation kinetics was studied as well. It is shown that the surface wettability is determinant to the energy dissipation mechanism in nanoscale. The influence of the surface wettability on the friction coefficient is presented. The observed correlation between the friction coefficient and contact angle enhances the influence of the surface wettability and its kinetics in the friction forces at nanoscale.
Darbellay, Georges Alexis. "Wetting and capillary condensation transitions in novel geometries." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303592.
Full textSoylemez, Emrecan. "Capillary Kinetics Between Multi Asperity Surfaces." Research Showcase @ CMU, 2014. http://repository.cmu.edu/dissertations/505.
Full textGemici, Zekeriyya. "Effects and applications of capillary condensation in ultrathin nanoparticle assemblies." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59875.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (p. 176-182).
The electrostatic layer-by-layer (LbL) assembly technique can be used to make uniform, conformal multi-stack nanoparticle thin films from aqueous solution, with precise thickness and roughness control over each stack. Much of the effort in this area has focused on the assembly and characterization of novel nanostructures. However, there is a scarcity of studies addressing critical barriers to commercialization of LbL technology, such as the lack of mechanical durability and the difficulty of incorporating a diverse set of functional organic molecules into aqueous solution-based nanoparticle assemblies. The versatility of existing chemical functionalization methods are limited by requirements for particular substrate surface chemistries, compatible solvents, and concerns over uncontrolled nanoparticle deposition. Here we describe the advantageous use of capillary condensation, a well-known natural phenomenon in nanoporous materials, as a more universal functionalization strategy. Capillary condensation of solvent molecules into nanoporous LbL films was shown to bridge neighboring nanoparticles via a dissolution-redeposition mechanism to impart mechanical durability to otherwise delicate films. In situ crosslinking ability of photosensitive capillary-condensates was demonstrated. Particle size-dependence of the capillary condensation process was studied theoretically and utilized experimentally to modulate refractive index over coating thickness to achieve broadband antireflection (AR) functionality. Multi-stack AR coatings with alternating high- and low-index stacks were also made, and the influence of inter-stack and surface roughness on film transparency were studied quantitatively. The equivalent-stack approximation was utilized and presented as an enabling design tool for fabricating sophisticated solution-based optical coatings. Surface wettability could also be modified using capillary condensation - either by condensation of adventitious vapors during an aging process leading to a loss of optimized film properties, or by advantageous condensation of carefully chosen hydrophobic or hydrophilic molecules to tune wettability. Finally, preliminary Young's moduli measurements of all-nanoparticle and polymer-nanoparticle composite films were made using strain induced elastic buckling instabilities for mechanical measurements (SIEBIMM).
by Gemici Zekeriyya.
Ph.D.
Sundararajan, Mayur. "X-ray Scattering Study Of Capillary Condensation In Mesoporous Silica." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1355943408.
Full textNasrallah, Hussein. "Capillary adhesion and friction : an approach with the AFM Circular Mode." Phd thesis, Université du Maine, 2011. http://tel.archives-ouvertes.fr/tel-00651818.
Full textHung, Francisco Rodolfo. "Capillary Condensation and Freezing of Simple Fluids Confined in Cylindrical Nanopores." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-08092005-232433/.
Full textKim, Seonmin. "Surface modification of metal oxide nanoparticles by capillary condensation and its application." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3852.
Full textThesis research directed by: Chemical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Pallares, Gaël. "Analyse multi-échelle des mécanismes de propagation de fissure dans les verres d'oxydes." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20072.
Full textThe aim of this thesis is to study the physical mechanisms which govern crack propagation in oxide glasses and to investigate in particular the existence of dissipative mechanisms at small scales. The subcritical crack propagation is controlled by a loading cell on Double Cleavage Drilled Compression samples under controlled atmosphere. Postmortem and in-situ analysis are performed on more than six decades of length scales (from nm to mm) by optical techniques and atomic force microscopy (AFM). An 2D/3D analysis of this sample is realized according to linear elastic fracture mechanics in order to discuss the experimental results and to ensure the mechanical test control at all scales. The mechanical effect of capillary condensation observed by AFM at the crack tip is modelled according to a cohesive zone model. This allows evaluating the negative Laplace pressure in the liquid and explaining the crack closure mechanism in glass. A digital image correlation technique is used on series of consecutive AFM in-situ images. We show that the elastic solution for the surface displacement field is valid up to a distance of 10 nm from the crack tip. A promising experimental study of fractoemission allowed us to access the nanometric process zone size in glasses during dynamic fracture. The height correlation functions along the AFM images of fracture surfaces were analyzed. We show that the cutoff length, found close to few ten nm and preiously interpreted as the process zone size, is most probably due to the finite size of the AFM scanning probe and in agreement with the DIC, no process zone larger than 20 nm is observable
Lysek, Mark Joseph Goodstein David L. Goodstein David L. "A thermodynamic study of layering and capillary condensation of methane adsorbed on graphite foam /." Diss., Pasadena, Calif. : California Institute of Technology, 1992. http://resolver.caltech.edu/CaltechETD:etd-08142007-090035.
Full textChau, Alexandre. "Theoretical and experimental study of capillary condensation and of its possible application in micro-assembly." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210619.
Full textThe first part of this work details a review of literature of different fields involved in capillary condensation. A simulation tool is then implemented and theoretically validated in the second part of the work. Finally, a test bed is presented; this bed is then used to experimentally validate the simulation results.
Experiments and simulation results are shown to concord. Therefore, the simulation tool can be used to model the force due to capillary condensation.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Huang, Xixi. "Influence des particules fines sur la stabilité d'un milieu granulaire." Phd thesis, Ecole Centrale de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00963654.
Full textLi, Xihao. "Characterization of Perphenazine and Scopolamine Aerosols Generated Using the Capillary Aerosol Generator." VCU Scholars Compass, 2006. http://scholarscompass.vcu.edu/etd/901.
Full textMaeda, Nobuo, and nobuo@engineering ucsb edu. "Phase Transitions of Long-Chain N-Alkanes at Interfaces." The Australian National University. Research School of Physical Sciences and Engineering, 2001. http://thesis.anu.edu.au./public/adt-ANU20011203.151921.
Full textGaroff, Niklas. "The Friction between Paper Surfaces." Doctoral thesis, Stockholm, 2002. http://www.diva-portal.org/kth/theses/abstract.xsql?dbid=3415.
Full textMoodley, Shawn. "Gas separation of steam and hydrogen mixtures using an α-alumina-Alumina supported NaA membrane / by S. Moodley." Thesis, North-West University, 2007. http://hdl.handle.net/10394/1890.
Full textWang, Haisheng. "Modélisation Morphologique et Propriétés de Transport d'Alumines Mésoporeuses." Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEM045/document.
Full textIn a work made at Centre de Morphologie Mathématique and IFPEN, we study the microstructure and physical properties of mesoporous alumina. This is a catalyst carrier used in the petroleum refining industry. Highly porous, it contains disordered ''platelets'' at the nanoscale. The mass transport properties of the catalyst carrier are strongly influenced by the morphology of the porous microstructure. We focus on the modeling of the microstructure and of transport properties of mesoporous alumina, using numerical and theoretical tools derived from image analysis and random sets models. On the one hand, methods are developed to characterize and model the microstructure, by extracting and combining information from transmission electron microscope (TEM) images and nitrogen porosimetry curves, among others. On the other hand, the numerical homogenization relies on full-field Fourier transform computations (FFT).The material is first characterized experimentally by nitrogen porosimetry and pulse-field gradient nuclear magnetic resonance (PFG-NMR). TEM images, obtained on samples of various thicknesses are filtered and measured in terms of correlation function. The high-frequency noise caused by carbon membrane support is identified and integrated in the TEM image model. Based on the 2D TEM images, a two-scale random set model of 3D microstructure is developed. It takes into account the platelet shape, platelet size, local alignments and aggregations effects which are numerically identified. The procedure is validated by comparing the model and experimental images in terms of correlation function and specific surface area estimated by nitrogen porosimetry.Next, a procedure is proposed to simulate porosimetry isotherms in general porous media, including random microstructures. Based on simple morphological operations, it extends an earlier approach of mercury porosimetry. Multilayer adsorption at low pressure is simulated by a dilation operation whereas the menisci of the vapor-liquid interface occurring during adsorption are simulated by closing the solid phase with spherical structuring elements. To simulate desorption, a combination of closing and hole-filling operations is used. The desorption threshold is obtained from a percolation analysis of the gaseous phase. The method, validated first on simple geometries, is compared to previous results of the literature, allowing us to predict the hysteresis and pore size distribution associated to porosimetry. It is applied on 3D microstructures of mesoporous alumina. To account for the pressure threshold during desorption, we propose a refined three-scale model for mesoporous alumina, that reproduces the correlation function and the desorption branch of porosimetry isotherms.Finally, Fick diffusion, Darcy permeability, and elastic moduli are numerically predicted using the FFT method and the two-scale and three-scale models of mesoporous alumina. The hindering effects in diffusion are estimated by the Renkin's equation. The effective diffusion coefficients and the tortuosity factors are estimated from the flux field, taking into account hindering effects. The effects of platelet shape, alignment and aggregation on the diffusion property are studied. The numerical estimation is validated from experimental PFG-NMR results
PUKHOVA, VALENTINA. "DYNAMIC ATOMIC FORCE MICROSCOPY RESOLVED BY WAVELET TRANSFORM." Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/259234.
Full textDevečka, Viktor. "Náhrada expanzního ventilu kapilární trubicí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254385.
Full textRestagno, Frédéric. "Interactions entre contacts solides et cinétique de la condensation capillaire. Aspects macroscopiques et aspects microscopiques." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2000. http://tel.archives-ouvertes.fr/tel-00001627.
Full textforces de cohésion. Nous nous sommes intéressés dans un premier temps à l'étude de l'évolution lente,
ou «vieillissement», de l'angle d'avalanche avec l'âge du tas. Nous avons montré que l'augmentation logarithmique
du coefficient de friction effectif entre les billes dépend de l'humidité de l'atmosphère, ce
qui peut être expliqué quantitativement par une augmentation progressive de la force d'adhésion due à
la condensation de liquide entre les grains. Nous avons également mis en évidence d'autres paramètres
influençant le vieillissement : usure, position du tas au repos ; et observé des effets de vieillissement en
présence d'éthanol. Nous avons étudié en détail la métastabilité et les effets de nucléation de la condensation
capillaire. Nous avons calculé l'énergie d'activation pour condenser un pont liquide entre deux surfaces
parallèles parfaitement lisses. Cette énergie d'activation diverge quand la taille du confinement s'approche
de la distance critique de nucléation. Ainsi, l'énergie d?activation est très souvent très supérieure à l'énergie
d'agitation thermique. Nous avons ensuite montré qu'il est possible de faire un modèle de condensation
capillaire thermiquement activé entre les rugosités des billes qui rend compte de la dépendance temporelle
du vieillissement observé avec les billes de verre. Enfin, nous avons construit un appareil à forces de surface
qui permet d'étudier les interactions statiques et dynamiques entre les surfaces à l'échelle du rayon de Kelvin,
c'est à dire à l'échelle du nanomètre. Après avoir décrit le principe et les performances de cet appareil,
nous exposons des premiers résultats concernant la nanorhéologie de fluides simples en milieu confiné ainsi
que des mesures de la dépendance de la force d'adhésion entre des surfaces de verre par rapport à la force
normale et au temps de contact.
Restagno, Frédéric. "Interactions entre contacts solides et cinetique de la condensation capillaire. Aspects macroscopiques et aspects microscopiques." Lyon, École normale supérieure (sciences), 2000. http://www.theses.fr/2000ENSL0173.
Full textDetcheverry, François. "Condensation capillaire et transitions hors d'équilibre dans les milieux poreux désordonnés : l'exemple des aérogels de silice." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2005. http://tel.archives-ouvertes.fr/tel-00011232.
Full textNotre modélisation prend pleinement en compte le caractère désordonné et hors d'équilibre du système fluide-aérogel. Le fluide est représenté par un gaz sur réseau et l'aérogel est décrit de manière réaliste à l'aide d'un algorithme d'agrégation de "clusters" limitée par diffusion (DLCA). Le caractère "coarse-grained" de notre description permet d'étudier les phénomènes collectifs se produisant à une échelle supérieure à celle des cavités de l'aérogel. Le modèle est traité dans le cadre d'une théorie de champ moyen local, qui définit un paysage de grand potentiel. On peut négliger les processus activés, comme le suggèrent les expériences, et le système-modèle évolue dès lors dans ce paysage selon une dynamique de température nulle, ne changeant de configuration que lorsqu'un paramètre extérieur (potentiel chimique) est modifié.
Cette modélisation nous permet d'élucider la nature des phénomènes d'adsorption. Le désordre imposé par l'aérogel induit, pour une température assez basse, un paysage de grand potentiel complexe, caractérisé par un grand nombre d'états métastables. Le système y évolue par une succession d'avalanches, qui sont des événements irréversibles de condensation (ou d'évaporation) en général microscopiques. Cette dynamique d'avalanche dans un paysage complexe est à l'origine de l'hystérésis. La forme des boucles d'hystérésis dépend du mécanisme à l'oeuvre, mécanismes qui diffèrent à l'adsorption et à la désorption, et changent avec la porosité et la température. On observe en particulier des transitions de phase hors d'équilibre identiques à celles qui existent dans le RFIM à température nulle. A l'adsorption, l'isotherme est soit discontinue soit continue selon qu'il existe une avalanche de taille macroscopique ou des avalanches seulement microscopiques ; ces deux régimes sont séparées par une ligne critique correspondant à la transition d'avalanche. A la désorption, trois mécanismes distincts sont mis en évidence : le premier est la cavitation, les deux autres sont des transitions qui mettent en jeu l'interface entre le fluide adsorbé et le réservoir de gaz : transition de percolation d'invasion et transition de dépiégeage. Nous montrons que de manière générale, il est difficile d'établir un lien direct entre la structure de l'aérogel et les caractéristiques des isothermes.
Dans la dernière partie de ce travail, nous étudions le rapport entre métastabilité et hystérésis en considérant le cas du RFIM sur réseau de Bethe à température nulle. Par des calculs analytiques, nous établissons un lien entre la boucle d'hystérésis et la répartition des états métastables dans le plan champ magnétique-aimantation.
Grimaldi, Antoine. "Etude par AFM de la condensation capillaire à la pointe de fissure dans un verre de silice." Montpellier 2, 2009. http://www.theses.fr/2009MON20246.
Full textThe phenomenon of stress corrosion is responsible for the slow crack propagation in glasses below their breaking point. In applications where glass components such as windows, fiber optic cables or glass containers are subjected to stresses, failure always occurs by the extension of a crack originated near the surface of the glass. The stress corrosion mechanisms acting et the nanoscale are still debated. The experimental set-up allows us to track the propagation of the crack tip in pure mode I (opening mode) by means of optical and atomic force microscopes (AFM) in real time (in-situ) condition and in a carefully controlled atmosphere. This work focuses specially on the capillary condensation that occurs at the crack tip in silica glass. In a first part, we have shown by using AFM phase imaging the existence of a liquid phase at the crack tip. We have focused in identifying all the bias induced by the external parameters in our measurement. In a second part, we have studied the equilibrium properties of this liquid/vapour system, and shown the existence of a critical distance of condensation between the two lips of the crack that increases with the humidity. At last, we have studied the impact of the internal forces du to the capillary condensation on the crack opening profile. By studying the crack closure we have been able to correct our estimation on the critical distance and extract the value of the Laplace pressure of the liquid. This allowed us to quantify the aging if the condensed phase through the evolution of its wetting properties
Detcheverry, François. "Condensation capillaire et transitions hors d' équilibre dans les milieux poreux désordonnées : l' exemple des aérogels de silice." Paris 6, 2005. https://tel.archives-ouvertes.fr/tel-00011232.
Full textEl, Mghari Hicham. "Étude expérimentale et numérique de la condensation capillaire d’une vapeur dans un micro-canal : Impact de la géométrie." Caen, 2014. http://www.theses.fr/2014CAEN2023.
Full textThis work presents experimental and numerical studies of condensation heat transfer in microcapillary tube. The experimental section is consituted by a transparent circular or non-circular microtube cooled by a constnt heat flux and alimented by a vapor mass flux. Experimental set up is elaborated to characterize the two-phase flow (liquid-vapor) inside the microchannel as a function of cooling conditions (power, mass flux and temperature), velocity and hydraulic diameter. A particular attention is focussed to the flow structure determined by images processing. Experimental results concerning pressure and temperature of condensing flow combined to image processing data are used to characterize the flow. Numerical modeling of annular condensing flow in micro-channel is conducted. Effect of tube geometry on the physical characterictics is investigated. At the end of this work, a preliminary study of condensation of nanofluids in a square microcapillary tube is conducted
Joncourt, Laurent. "Réactivité des matériaux carbones vis-à-vis du sodium." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0200.
Full textThis work is related to the interaction of sodium with carbon materials in particular with three graphitizable pitch coke and seven different anthracites. Indeed, these carbons are widely used as cathodic materials in the aluminum electrolysis cells, and there is a general agreement that the penetration of sodium atoms is responsible of the swelling and subsequent destruction of the electrode. At first, we tried to describe the evolution of the microtexture of these materials during heat treatment. Our results (X ray diffraction, Raman spectroscopy and pycnometry) show that the anthracites are highly porous, heterogeneous compounds. They are found to evolue at about 2000-2400°C to become partially graphitizable carbons. Concerning the interaction of sodium with these materials, three phenomena are observed : intercalation, adsorption and capillary condensation. The sodium intercalation is found to be very sensitive to the previous heat treatment temperature : the uptake of intercalated sodium is all the more important the heat treatment temperature is lower. The non-intercalated sodium uptake is correlated to the porous texture of these materials
Knorst-Fouran, Auriane. "Contribution à l’étude de propriétés interfaciales d’alcanes confinés par simulation moléculaire de type Monte Carlo." Pau, 2010. http://www.theses.fr/2010PAUU3027.
Full textThis work concerns the modelling of interfacial properties of linear alkanes confined in slit pores, such as adsorbed quantities or interfacial tension by the Monte Carlo molecular simulation. The simulations were performed at various thermodynamic conditions ranging from very low pressures and temperatures to higher values typical of reservoirs. We have studied the influence of three classical interaction potentials, the effect of confinement and thermodynamic conditions on confined methane, the isosteric heat of adsorption and the phenomenon of capillary condensation. Adsorption isotherms obtained with Monte Carlo simulation were successfully compared with experimental results. This study has also underlined the impact of the porous media characterization on the estimation of adsorption. The behavior of alkanes with longer chains was also determined
Dourdain, Sandrine. "Caractérisation structurale, poreuse et mécanique de films minces de silice mésoporeuse.Influence de la fonctionnalisation." Phd thesis, Université du Maine, 2006. http://tel.archives-ouvertes.fr/tel-00201895.
Full textLes paramètres pertinents influençant la structuration des films minces ont été appréhendés. En particulier, des études in situ par réflectivité des rayons X et par Diffusion en incidence rasante des rayons X (Grazing Incidence Small Angle X-ray Scattering, GISAXS), ont permis de mettre en évidence le rôle prédominant de l'humidité relative. Des protocoles d'extraction par rinçage à l'éthanol ont été établis pour dégager efficacement les structures mésoporeuses sans les écraser.
Une méthode d'analyse de la porosité des films minces a ensuite été développée. Cette méthode est basée sur l'analyse quantitative des courbes de réflectivité par la méthode matricielle. Complémentée par l'analyse des clichés GISAXS, elle nous a permis de déterminer sur couche mince non seulement la porosité, la taille des pores et des murs mais aussi la surface spécifique et la distorsion des pores.
Les pores de ces films mésoporeux ont une dimension idéale pour y parfaire l'étude de la condensation capillaire de l'eau. Quand l'eau pénètre dans les pores, le contraste de densité électronique décroît fortement. Ainsi, les techniques de diffusion des rayons X (réflectivité et GISAXS) permettent de suivre les isothermes de condensation et de désorption de l'eau dans les pores. La distribution de taille des pores peut alors être obtenue. Les isothermes d'adsorption d'eau ont permis également d'estimer la porosité, mais aussi d'appréhender par le biais de l'équation de Laplace, les propriétés mécaniques des films en accédant à leur module d'Young.
Finalement nous avons conclu cette thèse par l'étude de la fonctionnalisation des films par divers groupements fonctionnels localisés à la surface des mésopores, dans l'optique de modifier leur hydrophilicité ou leur réactivité chimique.
Baudequin, Maud. "Identification des mécanismes physiques mis en jeu lors de la reprise d'épaisseur de la laine de verre." Paris 6, 2002. http://www.theses.fr/2002PA066556.
Full textGirardot, Marie. "Aptamères et électrophorèse capillaire : caractérisation physico-chimique d'aptamères libres en solution ou greffés sur des nanoparticules, et étude de leur affinité avec une cible protéique en vue de leur emploi pour des méthodes sensibles de diagnostic." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://pastel.archives-ouvertes.fr/pastel-00553765.
Full textKohonen, Mika M. "Experiments on capillary condensation." Phd thesis, 2001. http://hdl.handle.net/1885/147616.
Full textQiao, Ying. "On adsorption, wetting and capillary condensation." Phd thesis, 2001. http://hdl.handle.net/1885/148082.
Full textWanless, Erica Joy. "Adsorption at interfaces : electrodeposition & capillary condensation." Phd thesis, 1994. http://hdl.handle.net/1885/139971.
Full textLilly, Michael Patrick. "Hysteretic capillary condensation and avalanche phenomena of He(4) in Nuclepore." 1997. https://scholarworks.umass.edu/dissertations/AAI9721469.
Full textTing-Rong, Lu, and 呂定蓉. "Measurement of DNA Counterion Condensation Due To Charge and Conformation Changes by Capillary Electrophoresis." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/70317825389247982237.
Full text淡江大學
化學學系
89
DNA, a biopolymer bearing high negative charge, would be neutralized by electrostatic reaction with cationic counterions. In this study we measured DNA charge and conformation changes induced by the competing binding reactions of monovalent and multivalent counterions with DNA by using capillary electrophoresis techniques. The measured DNA mobility reduction after charge neutralization reaction could be used for the calculations of charge neutralization fraction and end-to-end distance change. The effects of cationic charge and concentration, ionic strength, DNA fragment size, and electroosmotic flow on the reductions of DNA electrophoretic mobilities were investigated. Three electrophoretic migration modes were observed for DNA fragments in the size range of 72 bp to 23.13kbp in this study. The measured charge neutralization fractions increased with increasing DNA fragment sizes and reached a plateau value (e.g., 0.873 for [Mg2+]=1000μΜ,0.25×TB, which was close to the DNA collapse point.) when the corresponding DNA fragments adopted the reptation with stretching model as the electrophoretic migration mechanism. We observed an increase in DNA charge neutralization fraction and a decrease in its end-to-end distance when increasing multivalent cation concentration or decreasing the ionic strength of the buffer. This observation was in agreement with the prediction of Manning’s counterion condensation theory. Under equivalent ionic strength, the charge neutralization abilities of various multivalent cations studied had the order of Spermine4+ > Co(NH3)63+ > Spermidine3+ > Mg2+ > Co2+ > Zn2+ > Cu2+. This order was the same as the result obtained for the calculation of end-to end distance change.
Lysek, Mark Joseph. "A thermodynamic study of layering and capillary condensation of methane adsorbed on graphite foam." Thesis, 1992. https://thesis.library.caltech.edu/3119/1/Lysek_mj_1992.pdf.
Full textIvanova, Nina. "Improved Synthetic Methods for Patchy Particles." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10211.
Full textMaeda, Nobuo. "Phase Transitions of Long-Chain N-Alkanes at Interfaces." Phd thesis, 2001. http://hdl.handle.net/1885/47795.
Full textBeisel, Nadine. "Patterns of post-translational histone modifications, chromatin condensation and DNA fragmentation during apoptosis." Doctoral thesis, 2005. http://hdl.handle.net/11858/00-1735-0000-0006-ABBA-9.
Full textDaian, Jean-Francois. "Processus de condensation et de transfert d'eau dans un matériau meso et macroporeux : étude expérimentale du mortier de ciment." Phd thesis, 1986. http://tel.archives-ouvertes.fr/tel-00686400.
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