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Journal articles on the topic "Heterogeneous membranes"

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Strzelewicz, Anna, Monika Krasowska, and Michał Cieśla. "Lévy Flights Diffusion with Drift in Heterogeneous Membranes." Membranes 13, no. 4 (April 7, 2023): 417. http://dx.doi.org/10.3390/membranes13040417.

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The modelling of diffusion in membranes is essential to understanding transport processes through membranes, especially when it comes to improving process efficiency. The purpose of this study is to understand the relationship between membrane structures, external forces, and the characteristic features of diffusive transport. We investigate Cauchy flight diffusion with drift in heterogeneous membrane-like structures. The study focuses on numerical simulation of particle movement across different membrane structures with differently spaced obstacles. Four studied structures are similar to real polymeric membranes filled with inorganic powder, while the next three structures are designed to show which distribution of obstacles can cause changes in transport. The movement of particles driven by Cauchy flights is compared to a Gaussian random walk both with and without additional drift action. We show that effective diffusion in membranes with an external drift depends on the type of the internal mechanism that causes the movement of particles as well as on the properties of the environment. In general, when movement steps are provided by the long-tailed Cauchy distribution and the drift is sufficiently strong, superdiffusion is observed. On the other hand, strong drift can effectively stop Gaussian diffusion.
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Magnone, Edoardo, Jae Yeon Hwang, Min Chang Shin, Xuelong Zhuang, Jeong In Lee, and Jung Hoon Park. "Al2O3-Based Hollow Fiber Membranes Functionalized by Nitrogen-Doped Titanium Dioxide for Photocatalytic Degradation of Ammonia Gas." Membranes 12, no. 7 (July 6, 2022): 693. http://dx.doi.org/10.3390/membranes12070693.

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In recent years, reactive ammonia (NH3) has emerged as a major source of indoor air pollution. In this study, Al2O3-based hollow fiber membranes functionalized with nitrogen-doped titanium dioxide were produced and successfully applied for efficient heterogeneous photocatalytic NH3 gas degradation. Al2O3 hollow fiber membranes were prepared using the phase inversion process. A dip-coating technique was used to deposit titanium dioxide (TiO2) and nitrogen-doped titanium dioxide (N-TiO2) thin films on well-cleaned Al2O3-based hollow fiber membranes. All heterogeneous photocatalytic degradation tests of NH3 gas were performed with both UV and visible light irradiation at room temperature. The nitrogen doping effects on the NH3 heterogeneous photocatalytic degradation capacity of TiO2 were investigated, and the effect of the number of membranes (30, 36, 42, and 48 membranes) of the prototype lab-scale photocatalytic membrane reactor, with a modular design, on the performances in different light conditions was also elucidated. Moreover, under ultraviolet and visible light, the initial concentration of gaseous NH3 was reduced to zero after only fifteen minutes in a prototype lab-scale stage with a photocatalytic membrane reactor based on an N-TiO2 photocatalyst. The number of Al2O3-based hollow fiber membranes functionalized with N-TiO2 photocatalysts increases the capacity for NH3 heterogeneous photocatalytic degradation.
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Septiawan, Muhammad Ridwan, Dian Permana, Sitti Hadijah Sabarwati, La Ode Ahmad, and La Ode Ahmad Nur Ramadhan. "Functionalization of Chitosan with Maleic Anhydride for Proton Exchange Membrane." Indonesian Journal of Chemistry 18, no. 2 (May 30, 2018): 313. http://dx.doi.org/10.22146/ijc.33141.

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Chitosan was modified by maleic anhydride, and it was then functionalized using heterogeneous and blending method to obtain the membrane. The results of the reaction between chitosan with maleic anhydride were signed by the new peak appears around 1475 cm-1 which attributed to C=C bending of alkene. The new peak also appears at 1590 cm-1 which attributed to N-H bending of amide. Chitosan-maleic anhydride membranes show microstructure of chitosan membrane with high porous density and rigidity while chitosan-maleic anhydride membranes have clusters. In addition, the thermal tenacity of membranes reached 500 °C. Modified membrane by heterogeneous and blending method have higher water uptake, ion exchange capacity, and proton conductivity than chitosan membrane. Moreover, the blending method is much more effective than the heterogeneous method that can be exhibited from ion exchange capacity and proton conductivity values of 1.08–6.38 meq g-1 and 1x10-3–1x10-2 S cm-1, 0.92–2.27 meq g-1 and 1.53x10-4–3.04x10-3 S cm-1, respectively. The results imply that modification of chitosan membrane with the addition of maleic anhydride using heterogeneous and blending method can be applied to proton exchange membrane.
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Hosseini, S. M., Z. Ahmadi, M. Nemati, F. Parvizian, and S. S. Madaeni. "Electrodialysis heterogeneous ion exchange membranes modified by SiO2 nanoparticles: fabrication and electrochemical characterization." Water Science and Technology 73, no. 9 (February 2, 2016): 2074–84. http://dx.doi.org/10.2166/wst.2016.030.

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In the current study mixed matrix heterogeneous cation exchange membranes were prepared by solution casting technique. The effect of SiO2 nanoparticles in the polymeric solution on the physicochemical properties of prepared membranes was studied. Scanning optical microscope images showed uniform particle distribution and relatively uniform surfaces for the prepared membranes. The membrane water content was reduced by silica nanoparticles in the membranes' matrix. The membrane ion exchange capacity, membrane potential, transport number and selectivity were improved initially by an increase of SiO2 nanoparticles concentration up to 1%wt in prepared membranes and then showed a decreasing trend with a further increase in additive ratio from 1 to 4%wt. The ionic permeability and flux were also decreased initially by an increase of silica nanoparticles concentration up to 0.5%wt in the membrane matrix and then increased again with a further increase in nanoparticles concentration from 0.5 to 4%wt. Moreover, the results exhibited that using silica nanoparticles in the membrane matrix caused an obvious decrease in areal electrical resistance. The opposite trend was found for membrane mechanical strength using SiO2 nanoparticles.
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Reigada, Ramon. "Electroporation of heterogeneous lipid membranes." Biochimica et Biophysica Acta (BBA) - Biomembranes 1838, no. 3 (March 2014): 814–21. http://dx.doi.org/10.1016/j.bbamem.2013.10.008.

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Zárybnická, Lucie, Eliška Stránská, Kristýna Janegová, and Barbora Vydrová. "The effect of 3D printing parameters on electrochemical properties of heterogeneous cation exchange membrane." Rapid Prototyping Journal 27, no. 8 (August 2, 2021): 1538–47. http://dx.doi.org/10.1108/rpj-08-2020-0207.

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Purpose The study aims to focus on the preparation of a heterogeneous cation exchange membrane by a three-dimensional (3D) method – fused filament fabrication using a series of nozzles of various diameters (0.4–1.0 mm). Polypropylene random copolymer (PPR) as a polymeric binder was mixed with 50 Wt.% of the selected conventional cation exchange resin, and a filament was prepared using a single screw mini extruder. Then filament was processed by FFF into the membranes with a defined 3D structure. Design/methodology/approach Electrochemical properties, morphology, mechanical properties and water absorption properties were tested. Findings Dependence of the tested properties on the used nozzle diameter was found. Both areal and specific resistances increased with increasing nozzle diameter. The same trend was also found for permselectivity. The optimal membrane with permselectivity above 90%, areal resistance of 8 O.cm2 and specific resistance of 124 O.cm2 was created using a nozzle diameter of 0.4 mm. Originality/value Using new materials for 3D print of cation exchange membrane with production without waste. The possibility of producing 3D membranes with a precisely defined structure and using a cheap 3D printing method. New direction of membrane structure formation. 3D-printed heterogeneous cation exchange membranes were prepared, which can compete with commercial membranes produced by conventional technologies. 3D-printed heterogeneous cation exchange membranes were prepared, which can compete with commercial membranes produced by conventional technologies.
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Polak, Daniel, and Maciej Szwast. "Material and Process Tests of Heterogeneous Membranes Containing ZIF-8, SiO2 and POSS-Ph." Materials 15, no. 18 (September 17, 2022): 6455. http://dx.doi.org/10.3390/ma15186455.

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Heterogeneous membranes made of a polymer matrix and containing nano-metric fillers in their structure may present improved physicochemical and process properties compared to homogeneous membranes made only of polymer materials. Membranes made of a PEBAX®2533 block copolymer were tested with fillers such as ZIF-8, SiO2 and POSS-Ph being dosed to them. The material analysis and process tests indicate that these nanomaterials can be used as fillers for heterogeneous membranes. Chemometric analyses determined the influence of individual fillers on selected physicochemical properties of the materials which were used to produce the membranes. For specific concentrations of these fillers, improvement in the permeability and selectivity of the membranes, or at least in one of these parameters, was achieved. The greatest increase in permeability against the homogeneous membrane was obtained for membranes containing 10 wt% ZIF-8 (for CO2, an increase of 2.07 times; for CH4, 2.36 times; for N2, 3.08 times). In turn, the greatest increase in selectivity was obtained for the CO2/CH4 mixture for the membrane containing 5 wt% SiO2 (1.15 times), and for the CO2/N2 mixture for the membrane containing 2 wt% POSS-Ph (1.21 times).
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Bejanidze, Irina, Oleksandr Petrov, Volodymyr Pohrebennyk, Tina Kharebava, Nunu Nakashidze, Nato Didmanidze, Nazi Davitadze, and Anton Petrov. "Sorption of Organic Electrolytes and Surfactants from Natural Waters by Heterogeneous Membranes." Applied Sciences 10, no. 20 (October 21, 2020): 7383. http://dx.doi.org/10.3390/app10207383.

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The widespread use of surfactants increasingly requires the development and application of reliable methods for the demineralization of wastewaters, preventing environmental pollution. One of the most reliable and effective methods of demineralization of wastewaters is the electrodialysis method. Studying the behavior of large organic ions in the membrane is important for modeling cell membranes and purification of medicinal and biological preparations. The sorption characteristics of the MA-40 and MK-40 ion-exchange membranes in solutions of simple and organic electrolytes, and in a solution of the surfactant were investigated. It was found that the sorption of organic ions by membranes is mainly of an ion-exchange nature. The moisture content and elasticity of the membranes decreases in solutions of organic electrolytes, during the sorption of which the membrane becomes brittle. A study showed that in the solutions of organic electrolytes, the MA-40 membrane retains high electrochemical activity, while the MK-40 in a solution of the surfactant completely loses it. From the data obtained in this work, it is shown that organic ions do not present a hazard when water is desalted by electrodialysis, whereas sorption of surfactant ions leads to membrane poisoning.
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Stenina, Irina A., and Andrey B. Yaroslavtsev. "Ionic Mobility in Ion-Exchange Membranes." Membranes 11, no. 3 (March 11, 2021): 198. http://dx.doi.org/10.3390/membranes11030198.

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Membrane technologies are widely demanded in a number of modern industries. Ion-exchange membranes are one of the most widespread and demanded types of membranes. Their main task is the selective transfer of certain ions and prevention of transfer of other ions or molecules, and the most important characteristics are ionic conductivity and selectivity of transfer processes. Both parameters are determined by ionic and molecular mobility in membranes. To study this mobility, the main techniques used are nuclear magnetic resonance and impedance spectroscopy. In this comprehensive review, mechanisms of transfer processes in various ion-exchange membranes, including homogeneous, heterogeneous, and hybrid ones, are discussed. Correlations of structures of ion-exchange membranes and their hydration with ion transport mechanisms are also reviewed. The features of proton transfer, which plays a decisive role in the membrane used in fuel cells and electrolyzers, are highlighted. These devices largely determine development of hydrogen energy in the modern world. The features of ion transfer in heterogeneous and hybrid membranes with inorganic nanoparticles are also discussed.
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Sarapulova, Veronika, Ekaterina Nevakshenova, Kseniia Tsygurina, Valentina Ruleva, Anna Kirichenko, and Ksenia Kirichenko. "Short-Term Stability of Electrochemical Properties of Layer-by-Layer Coated Heterogeneous Ion Exchange Membranes." Membranes 13, no. 1 (December 29, 2022): 45. http://dx.doi.org/10.3390/membranes13010045.

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Layer-by-layer adsorption allows the creation of versatile functional coatings for ion exchange membranes, but the stability of the coating and resulting properties of modified membranes in their operation is a frequently asked question. This paper examines the changes in voltammetric curves of layer-by-layer coated cation exchange membranes and pH-metry of desalination chamber with a studied membrane and an auxiliary anion exchange membrane after short-term tests, including over-limiting current modes. The practical operation of the membranes did not affect the voltammetric curves, but enhanced the generation of H+ and OH− ions in a system with polyethylenimine modified membrane in Ca2+ containing solution. It is shown that a distinction between the voltammetric curves of the membranes modified and the different polyamines persists during the operation and that, in the case of polyethylenimine, there is an additional zone of growth of potential drop in voltammetric curves and stronger generation of H+ and OH− ions as indicated by pH-metry.
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Dissertations / Theses on the topic "Heterogeneous membranes"

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Turner, Josephine. "Heterogeneous polyelectrolyte gel membranes, effect of morphology on stimulus-responsive permeation control." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq63593.pdf.

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Johns, Brian Douglas. "Experimental verification of pointwise identification method for capturing heterogeneous properties in membranes." Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/824.

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Faaland, Sonia. "Heterogeneous ceramic interfaces in solid oxide fuel cells and dense oxygen permeable membranes." Doctoral thesis, Norwegian University of Science and Technology, Department of Chemistry, 2000. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-53.

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Solid oxide fuel cells and oxygen permeable membranes have received considerable attention during the last decade due to the increasing demand for electrical energy and easily transportable fuels combined with the requirement of low emission of CO2. This work concentrates on the stability of ceramic interfaces in general, and more specifically to heterophase solid state interfaces related to solid oxide fuel cells and oxygen permeable membranes. Reaction mechanisms are discussed and requirements and properties of suitable materials are determined. This thesis consists of three parts: 1) Structure of Ca-substituted lanthanum manganite (Paper I), 2) Reactions between cathode and electrolyte for SOFC applications (Papers II-IV) and 3) Chemical and mechanical aspects of sealing dense oxygen permeable membranes (Papers V and VI).

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Tichy, Robin Sarah. "Mechanisms and stability of oxide-ion transport in homogenous and heterogeneous ceramic membranes /." Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3008457.

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Zhao, Xuefeng. "Pointwise identification of elastic properties in nonlinear heterogeneous membranes, and application to soft tissues." Diss., University of Iowa, 2009. https://ir.uiowa.edu/etd/222.

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Identifying the elastic properties of heterogeneous materials has long been a very challenging problem both theoretically and experimentally. When it comes to biological tissues, this task is even more difficult since biological tissues generally exhibit substantial anisotropic behavior. Moreover, identification is often required to be performed in the service condition of living human tissues and organs, i.e., in vivo. Presently, a method capable of performing such tasks is lacking. The primary goal of this study is to fill this gap by developing a novel experimental method, termed as pointwise identification method (PWIM), for delineating the elastic properties in nonlinear heterogeneous membranes. Fundamentally, the method hinges on a unique feature of membrane equilibrium problems, that is, wall stress can be determined from equilibrium consideration alone (static determinacy). Thanks to the static determinacy, membrane wall stress can be computed numerically by using finite element inverse elastostatics method (FEIEM), and depends minimally on the constitutive model. In PWIM, an inflation test is conducted for the target membrane with a series of tracking markers, and a series of deformed configurations are recorded by using appropriate motion tracking techniques. Subsequently, the pointwise stress distribution in each deformed configuration can be acquired independently by applying FEIEM, whereas the corresponding strain distribution can be determined from the deformation relative to the reference configuration which contains implicitly the elastic properties of the material. Consequently, the elastic properties at every material point can be extracted by fitting an appropriate constitutive model to the pointwise stress-strain data pairs. In this work, we have validated the method for nonlinear isotropic and anisotropic materials through numerical simulations on a patient-specific cerebral aneurysm model, developed an experimental system and validated the method experimentally by conducting an inflation test on a rubber balloon, and conducted a test on a rabbit urinary bladder. The situation of the global stress-free configuration being unknown was considered numerically by employing a concept of local stress-free configuration. In this regard, the method holds the promise of identifying in vivo the elastic properties of membrane-like living organs, e.g., cerebral aneurysms, using medical images upon the availability of powerful image registration techniques.
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Pandžić, Elvis. "Measurement of protein transport and confinement in heterogeneous membranes by k-space image correlation spectroscopy." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116842.

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This thesis presents the application of k-space Image Correlation Spec- troscopy (kICS) to the analysis of fluorescence microscopy image time series for the measurement of particle diffusion in heterogeneous membranes, composed of micro- domains. The extension, testing and application of kICS for such measurements is developed both in silico with simulation and with in vivo cellular experiments.Connections between kICS analysis and other existing fluorescent microscopy techniques used in the study of heterogeneous membranes, such as single particle tracking (SPT) and spot vary Fluorescence Correlation Spectroscopy (FCS) are introduced. This is followed by the development of kICS theory of fluorescent particle diffusion within a heterogeneous two dimensional (2D) environment. Two possible membrane heterogeneities, isolated lipid micro-domains and actin proximal meshwork, are considered separately. The emergent models suggest that the kICS correlation function (CF) can be fit by a sum of two Gaussians in the case of particle diffusion in the presence of isolated micro-domains. These two fit components, called 'fast' and 'slow', with the fast associated with the rapid decay of the kICS CF at small spatial frequencies due to particle motion on large spatial scales outside domains while the slow component refers to the confined particle motion on large spatial frequencies or small spatial scales in domains. On the other hand, the meshwork confinement is well fit with a single Gaussian model for the analysis of kICS CF. These models suggest that the exponents and amplitudes of the fits embed the characteristic system parameters such as diffusion coefficients outside and inside domains, the partitioning rates, micro-domains radii and mesh pore size.Furthermore, systematic simulations to study different confinement scenarios were conducted and the calculated kICS correlation functions were fit and the output interpreted for recovery of self system parameters. The characterization of the simulated data suggests that kICS CFs exhibit various confinement dependent features, such as decays due to effective slow and fast dynamics populations and effective domain sizes. The in silico characterization of different confinement scenarios, suggests a connection between the apparent measured confinement properties, and the set system defining parameters. We explore the range and limits where confinement effects can be detected and accurately measured by kICS analysis. Possible systematic errors in the values of the fit extracted parameters due to background noise is discussed with possible alternative solutions.Finally, we apply this extension of kICS to the heterogeneous membrane en- vironment to explore the confinement dynamics of GPI-GFP anchored proteins in the basal plasma membrane of COS-7 cells. We employ a novel labelling approach of GPI-GFP using anti-GFP-Alexa594 and image the protein in COS-7 cell mem- branes with TIRF microscopy. Cells were exposed to enzymatic treatments, using the Cholesterol Oxidase (COase) and Sphingomyelinase (SMase), in order to dis- rupt membrane domains and change GPI-GFP confinement dynamics. We observe that GPI-GFP mobility and the effective domain size measured correlates with the enzymatic exposure time. We attribute it to the conversion of the membrane domain constituents, cholesterol and sphingomyelin, upon the enzymatic reactions, leading to membrane domain that are effectively larger and leakier. Finally, we conclude with possible improvements and future directions.
La thèse qui suit est a propos de l'adaptation de la technique de la spectroscopie par la corrélation des images dans l'espace de Fourier, appelle kICS. La nouveauté consiste en utilisation de kICS pour analyser les séries temporelles d'images fluorescentes afin de caractériser la diffusion des particules en présence des membranes hétérogénes, composées de micro-domaines.Tout d'abord, une parallèle est exposée entre l'analyse fondée sur kICS pro- posé ci-dessus et d'autres techniques de microscopie à fluorescence existantes et utilisées dans l'étude des membranes hétérogénes. Ensuite, on expose le développement de la théorie de kICS dans les cas de la diffusion des particules fluorescentes dans un espace hétérogène bidimensionnel (2D). Les deux hétérogénéités membranaires possibles, micro-domaines lipidiques isolés et le réseau de l'actine proximale, sont considérés séparément. Les modèles émergents suggèrent que la fonction de corrélation de kICS doit être caractérisé par une somme de deux Gaussiennes dans le cas de la dynamique des particules en présence de micro-domaines isolés. Ces deux éléments, appelés 'rapide' et 'lent', représentent les composantes dynamiques a deux échelles d'espace différentes. La rapide est associé à la décroissance rapide de la fonction de corrélation de kICS à petites fréquences spatiales dues au mouvement des particules sur de grandes échelles spatiales. La composante lente réfère au mouvement des particules confinées à des petites échelles spatiales, observées sur de grandes fréquences spatiales de kICS. D'autre part, la fonction de corrélation de kICS due au confinement par le réseau du cytosquelette peut être caractérise par unique décroissance Gaussienne. Ces modèles suggèrent que les exposants et les amplitudes obtenus par la caractérisation de la fonction kICS dépend des paramètres caractéristiques du système tels que les coefficients de diffusion à l'extérieur et à l'intérieur de domaines, les taux de migration de particules vers intérieur ou extérieur de micro-domaines ou des tailles de porosités du réseaux du cytosquelette.Les études systématiques par les simulations des scénarios différents de confinement et leurs effets sur la fonction de corrélation de kICS ont été explorés. La caractérisation des données simulées suggèrent que les fonctions de corrélation ont des caractéristiques qui dépendent de confinement et les propriétés spécifiques, tels que la dynamique des populations lents et rapides et la tailles effective de micro-domaines. La caractérisation des scénarios de confinement différents, représente les liens entre les propriétés apparentes mesurées de confinement, et un ensemble de paramètres définissant hétérogénéité. Nous explorons les limites pour lesquelles des effets de confinement ne sont pas observées dans la fonction de corrélation kICS. Les éventuelles erreurs systématiques dans les valeurs des paramètres extraits à cause du bruit de fond est discuté avec des possibles solutions. Finalement, nous utilisons l'analyse afin d'explorer la dynamique de confinement de la protéine ancrée à GPI-GFP dans la membrane plasmique basale des cellules COS-7. Nous explorons une approche nouvelle de la conjugaison entre le GPI-GFP et les anti-GFP-Alexa594 et imagé par la microscopie TIRF. Les cellules ont été exposées à des traitements enzymatiques, par Coase et SMase, afin de perturber domaines membranaires et changer la dynamique de confinement de GPI-GFP. Les réactions enzymatiques augmentent la mobilité et la taille effective des domaines de GPI-GFP. Nous attribuons cela à la conversion des constituants des domaines, le cholestérol et la sphingomyéline, par les réactions enzymatiques, ce qui conduit aux plus grandes et moins étanches domaines membranaires.
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Pampel, André. "Pulsed field gradient NMR in combination with magic angle spinning - new possibilities for studying diffusion in lipid membranes and heterogeneous materials." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-197016.

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Pampel, André. "Pulsed field gradient NMR in combination with magic angle spinning - new possibilities for studying diffusion in lipid membranes and heterogeneous materials." Diffusion fundamentals 2 (2005) 128, S. 1-2, 2005. https://ul.qucosa.de/id/qucosa%3A14470.

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Abdalla, B. K. "Heterogeneous modelling of fixed bed and fluidized bed reactors without and with selected membranes for the catalytic dehydrogenation of ethylbenzene to styrene." Thesis, University of Salford, 1993. http://usir.salford.ac.uk/2029/.

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Besson, Arthur. "Etude de polymères pour l'utilisation en membranes de piles à combustible." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENI070/document.

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Les piles à combustible sont une technologie en pleine expansion dans le domaine du transport automobile.Les membranes polymères les plus utilisées actuellement dans ces systèmes sont celles à base de Nafion.Leur principal point faible se trouve dans leurs performances limitées au-delà de 80°C, où la membranedevient défaillante et l'eau ne peut plus assurer la conduction protonique. Le projet EUBECELL se proposede résoudre ce problème en mettant au point un système de pile à combustible fonctionnant à l'éthanol et àplus de 120°C. Cette thèse s'inscrit dans ce projet et se concentre sur l'élaboration de nouvelles membranespolymères conductrices de protons. Deux voies sont envisagées : l'amélioration des propriétés du Nafion àhaute température et le remplacement du Nafion par un polymère haute performance auquel on donne uneconductivité.L'amélioration du Nafion se fait par l'ajout de conducteurs liquides ioniques protiques (CLIPs), produitsayant donc une conductivité protonique venant s'ajouter à celle du Nafion. Un premier CLIP est synthétisé,caractérisé puis ajouté au Nafion et les performances des membranes obtenues mesurées. Les résultatsencourageants obtenus incitent à synthétiser d'autres CLIPs à partir de la même amine et en variant le contreion.D'autres mélanges Nafion-CLIPs sont ainsi synthétisés et caractérisés.Les polymères hautes performances étudiés ici pour remplacer le Nafion sont dans un premier temps despolysulfones sulfonées. Les polysulfones étant des polymères qui résistent aux températures élevées et lasulfonation leur donnant une conductivité. Pour conserver de meilleures propriétés après sulfonation, nousprocédons à une extrusion du film polymère suivi d'une sulfonation. Nous mettons donc au point unprotocole de sulfonation hétérogène. Les membranes obtenues sont ensuite caractérisées et leursperformances mesurées. Dans un deuxième temps nous travaillons sur des membranes macroporeuses, àforte tenue mécanique, que nous remplissons avec les CLIPs utilisés auparavant. Les membranes sont alorsaussi caractérisées et leurs performances mesurées
Fuel cells are an ever-expanding technology in the field of automotive transport. The polymer membranesthat are currently the most widely used are Nafion-based membranes. Their weakest point is their drastic lossof performances beyond the threshold of 80°C, where the membranes fails and water cannot ensure protonconduction anymore. The EUBECELLproject sets to achieve making a fuel cell system functioning above120°C and using ethanol as a fuel. This thesis is part of the project and focus on elaborating new protonconductingpolymer membranes. Two main ways are explored: improving the performances of Nafion athigh temperature and replacing Nafion with conductivity-added high-performance polymers.Improving Nafion's performances is achieved by adding proton conducting ionic liquids (PCILs), productsthat have a proton conductivity that adds to Nafion's own. A first PCIL is synthesized, characterized and thenadded to Nafion, the resulting membranes' performances then measured. The encouraging results that weobtain makes us synthesize more PCILs, from the same amine than the first, varying the counter-ion. OtherNafion-PCIL mixes are made and then characterized.The high-performance polymer investigated for replacing Nafion are, first, sulfonated polysulfones.Polysulfones are high-temperature resistant polymers and sulfonation gives them conductivity. To keep betterproperties after the sulfonation, we proceed to extrude the films before sulfonating them. We elaborate anheterogeneous sulfonation protocol for them. The resulting membranes are then characterized and theirperformances measured. Second, we work on macroporous membranes, with high mechanical strength,which we fill with the PCILs that we previously used. The membranes are then also characterized and theirperformances measured
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Books on the topic "Heterogeneous membranes"

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Turner, Josephine. Heterogeneous polyelectrolyte gel membranes: Effect of morphology on stimuli-responsive permeation control. 2001.

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Doraiswamy, L. K. Organic Synthesis Engineering. Oxford University Press, 2001. http://dx.doi.org/10.1093/oso/9780195096897.001.0001.

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This book will formally launch "organic synthesis engineering" as a distinctive field in the armory of the reaction engineer. Its main theme revolves around two developments: catalysis and the role of process intensification in enhancing overall productivity. Each of these two subjects are becoming increasingly useful in organic synthesis engineering, especially in the production of medium and small volume chemicals and enhancing reaction rates by extending laboratory techniques, such as ultrasound, phase transfer catalysts, membrane reactor, and microwaves, to industrial scale production. This volume describes the applications of catalysis in organic synthesis and outlines different techniques of reaction rate and/or selectivity enhancement against a background of reaction engineering principles for both homogeneous and heterogeneous systems.
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Book chapters on the topic "Heterogeneous membranes"

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Anderson, M. A., F. Tiscareño-Lechuga, Q. Xu, and C. G. Hill. "Catalytic Ceramic Membranes and Membrane Reactors." In Novel Materials in Heterogeneous Catalysis, 198–215. Washington, DC: American Chemical Society, 1990. http://dx.doi.org/10.1021/bk-1990-0437.ch019.

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Higa, Mitsuru. "Heterogeneous Ion-Exchange Membranes." In Encyclopedia of Membranes, 915–16. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-44324-8_278.

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Higa, Mitsuru. "Heterogeneous Ion-Exchange Membranes." In Encyclopedia of Membranes, 1–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-40872-4_278-1.

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Marguet, Didier, and Laurence Salomé. "Lateral Diffusion in Heterogeneous Cell Membranes." In Physics of Biological Membranes, 169–89. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-00630-3_7.

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Leysen, R., W. Doyen, R. Proost, Ph Vermeiren, W. Adriansens, and R. Deknock. "THE USE OF HETEROGENEOUS MEMBRANES IN ELECTROCHEMICAL SYSTEMS." In Synthetic Polymeric Membranes, edited by Blahoslav Sedláček and Jaroslav Kahovec, 89–100. Berlin, Boston: De Gruyter, 1987. http://dx.doi.org/10.1515/9783110867374-011.

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Ślęzak, A., B. Turczyriski, and Z. Nawrat. "IRREVERSIBLE THERMODYNAMICS MODEL EQUATIONS OF THE TRANSPORT ACROSS VERTICAL-MOUNTED MEMBRANE IN MULTICOMFONENT, NON-IONIC AND HETEROGENEOUS SOLUTIONS." In Synthetic Polymeric Membranes, edited by Blahoslav Sedláček and Jaroslav Kahovec, 445–52. Berlin, Boston: De Gruyter, 1987. http://dx.doi.org/10.1515/9783110867374-044.

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Levine, Zachary A. "Effects of Heterogeneous Membranes and Electrolytes on Electropore Formation." In Handbook of Electroporation, 1–22. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-26779-1_87-1.

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Schwille, Petra, Nicoletta Kahya, and Kirsten Bacia. "Protein and Lipid Partitioning in Locally Heterogeneous Model Membranes." In Protein-Lipid Interactions, 337–65. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/3527606769.ch14.

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Levine, Zachary A. "Effects of Heterogeneous Membranes and Electrolytes on Electropore Formation." In Handbook of Electroporation, 133–53. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-32886-7_87.

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Šachl, Radek, and Lennart B. Å. Johansson. "Heterogeneous Lipid Distributions in Membranes as Revealed by Electronic Energy Transfer." In Reviews in Fluorescence 2015, 171–87. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-24609-3_7.

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Conference papers on the topic "Heterogeneous membranes"

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Ghaffar, Mehmood, Niklas Biere, Daniel Jäger, Karsten Klein, Falk Schreiber, Olaf Kruse, and Björn Sommer. "3D Modelling and Visualisation of Heterogeneous Cell Membranes in Blender." In VINCI '18: The 11th International Symposium on Visual Information Communication and Interaction. New York, NY, USA: ACM, 2018. http://dx.doi.org/10.1145/3231622.3231639.

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Tabouillot, Tristan, Hari S. Muddana, and Peter J. Butler. "Shear Stress Induces Time- and Domain-Dependent Changes in Lipid Dynamics of Endothelial Cell Membranes." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206882.

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Endothelial cells (ECs) form the inner lining of the blood vasculature and are exposed to shear stress (τ), the tangential component of hemodynamic forces. ECs transduce τ into biochemical signals possibly via EC-membrane perturbations. We have previously used confocal-FRAP on the DiI-stained plasma membranes of confluent cultured bovine aortic ECs (BAECs) to show that τ induces a rapid, spatially heterogeneous, and time-dependent increase in the lateral diffusion of the fluorescent lipoid probe in the BAEC membrane [1]. We now present evidence at the single molecule level that shear stress differentially perturbs membrane domains that are defined by their selective staining by lipoid dyes (DiI) of differing alkyl chain lengths. This study is the first to directly measure perturbation by shear stress of endothelial cell membrane microdomains.
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Dehghannasiri, Razi, Reza Pourabolghasem, Ali Asghar Eftekhar, and Ali Adibi. "GHz Heterogeneous Phononic Crystal Slab Resonators." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-52765.

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In this paper, we present a new design for waveguide-based phononic crystal (PnC) resonators in pillar-based piezoelectric membranes at the GHz frequency range based on mode-gap waveguide termination. The mode confinement in these resonators is achieved by a smooth transition from a phononic waveguide to another phononic waveguide that does not support (and therefore reflects) the guided modes of the first waveguide over a certain frequency range. These resonators can be utilized for applications including wireless communications and sensing [1, 2] where high-Q and high-frequency resonators are highly desirable.
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Ahn, Geun Ho, Alexander D. White, Kevin Crust, Chris Andersson, Jakob Grzesik, Kasper Van Gasse, Giovanni Scuri, Harold Y. Hwang, and Jelena Vučković. "Silicon nitride electro-optic modulators enabled by heterogeneous integration of barium titanate films." In CLEO: Science and Innovations. Washington, D.C.: Optica Publishing Group, 2023. http://dx.doi.org/10.1364/cleo_si.2023.sf1p.7.

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De Groote, A., P. Cardile, A. Z. Subramanian, M. Tassaert, D. Delbeke, R. Baets, and G. Roelkens. "A waveguide coupled LED on SOI by heterogeneous integration of InP-based membranes." In 2015 IEEE 12th International Conference on Group IV Photonics (GFP). IEEE, 2015. http://dx.doi.org/10.1109/group4.2015.7305939.

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Kim, Jeehwan. "Advanced Heterogeneous Integration Enabled by 3D Freestanding Membranes—From Material Growths to Applications." In MRS Fall Meeting 2022. US DOE, 2022. http://dx.doi.org/10.2172/1961416.

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Kim, Jeehwan. "Advanced Heterogeneous Integration Enabled by 3D Freestanding Membranes—From Material Growths to Applications." In Materials Research Society, Boston, Nov 2022. US DOE, 2022. http://dx.doi.org/10.2172/1923272.

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Martins, N. C., L. B. Rodrigues, F. T. do Nascimento, G. M. da Silveira, J. F. Corte, M. V. Flach, M. A. S. Rodrigues, F. Celso, V. D. Jahno, and R. M. de Martins. "Evaluation of the influence of method preparation in properties of heterogeneous ion exchange membranes." In WASTE MANAGEMENT 2016. Southampton UK: WIT Press, 2016. http://dx.doi.org/10.2495/wm160351.

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Shadmani, Atefeh, Rodrigo Thomas, Zhe Liu, Nicolas Volet, Martijn J. R. Heck, Sven Scholz, Andreas D. Wieck, Arne Ludwig, Peter Lodahl, and Leonardo Midolo. "Integration of GaAs waveguides with quantum dots on Silicon substrates for quantum photonic circuits." In CLEO: QELS_Fundamental Science. Washington, D.C.: Optica Publishing Group, 2022. http://dx.doi.org/10.1364/cleo_qels.2022.ff4j.6.

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We present the heterogeneous integration of GaAs membranes with embedded quantum dots on a Silicon substrate, based on die-to-die bonding method. We demonstrate light transmission in GaAs nanobeam waveguides and emission from individual quantum emitters.
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Elturki, Mukhtar, and Abdulmohsin Imqam. "An Experimental Study Investigating the Impact of Miscible and Immiscible Nitrogen Injection on Asphaltene Instability in Nano Shale Pore Structure." In SPE International Conference on Oilfield Chemistry. SPE, 2021. http://dx.doi.org/10.2118/204294-ms.

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Abstract Miscible gas injection has become the most used enhanced oil recovery (EOR) method in the oil and gas industry. The deposition and precipitation of aspahltene during the gas injection process is one of the problems during the oil production process. The asphaltene can deposit and plug the pores, which reduces the permeability in a reservoir; thus, decreasing the oil recovery and increasing the production costs. This research investigates the nitrogen (N2) miscible and immiscible pressure injections on asphaltene instability in shale pore structures. First, a slim-tube was used to determine the minimum miscibility pressure (MMP) of N2 to ensure that the effect of both miscible and immiscible gas injection was achievable. Second, filtration experiments were conducted using a specially designed filtration apparatus to investigate the effect of nano pore sizes on asphaltene deposition. Heterogeneous distribution of the filter paper membranes was used in all experiments. The factors studied include miscible/immiscible N2 injection and pore size distribution. Visualization tests were conducted to highlight the asphaltene precipitation process over time. The results showed that increasing the pressure increased the asphaltene weight percentage. The miscible N2 injection pressure had a significant effect on asphaltene instability. However, the immiscible N2 injection pressure had a lower effect on the asphaltene deposition, which resulted in less asphaltene weight percentage. For both miscible/immiscible N2 injection pressures, the asphaltene weight percentage increased as the pore size of the filter membranes decreased. Visualization tests showed that after one hour the asphaltene clusters were clearly noticed and suspended in the solvent of heptane, and the asphaltene was fully deposited after 12 hours. Microscopy imaging of filter membranes indicated significant pore plugging from asphaltene, especially for smaller pore sizes.
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Reports on the topic "Heterogeneous membranes"

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Kearney, M., V. Kochergin, R. Hess, T. Foust, R. Herbst, and N. Mann. Industrial Membrane Filtration and Short-bed Fractal Separation Systems for Separating Monomers from Heterogeneous Plant Material. Office of Scientific and Technical Information (OSTI), March 2005. http://dx.doi.org/10.2172/838864.

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