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Stevar, M. S. P. "Dissolution dynamics of liquid/liquid binary mixtures in porous media." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/349974/.
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In this project has been undertaken an experimental study aimed at understanding the dissolution dynamics of binary mixtures within porous media. The porous medium can be roughly represented as a network of capillary tubes. This allowed for the initial research to be focused on understanding the dissolution dynamics of binary mixtures (i.e. glycerol/water, soybean oil/hexane, and isobutyric acid/water) within single capillary tubes. Further, the dissolution process was investigated within a 2D micromodel built as a network of capillary tubes. In the experiments with the capillary tubes, the dissolution (i.e. the interfacial mass transfer) could be isolated from the hydrodynamic motion while using glycerol/water and soybean oil/hexane binary mixtures. Despite the fact that these are fully miscible liquids, the interface could be observed for rather long time periods. In particular, two phase boundaries were observed moving from the ends into the middle section of the capillary tube with the speeds v∼D^1/3t^-2/3d^2(D, t and d are the coefficient of diffusion, time and diameter of the capillary tube, respectively). The boundaries slowly smeared but their smearing occurred very slow in comparison to their motion. The motion of the phase boundaries cannot be explained by the dependency of the diffusion coefficient on concentration, and could possibly be explained by the effect of barodiffusion. In addition, these solute/solvent boundaries were endowed with non-zero interfacial tension. This experimental study also revealed that the solvent penetration into the micromodel is diffusion-dominated for completely miscible binary mixtures. This is however non-Fickian diffusion with the dissolution rate dV/dt∼D^1/3t^-0.4 for almost the entire duration of the experiment (V is the volume occupied by the solvent, D is the diffusion coefficient and t is time). For the IBA/water mixture the experiments performed at undercritical temperatures revealed that the diffusive mass transport was negligible despite the mixture being out of its thermodynamic equilibrium. Despite a seeming simplicity of the experiments, to the author’s best knowledge, there is no theory that could correctly describe the observed diffusional penetration of a solvent into a solute-filled capillary tube and hence, into a more complex porous volume.
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Shin, Youn-Ok. "Vapor and liquid equilibria in porous media." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0022/MQ50659.pdf.
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Shin, Youn-Ok 1971. "Vapor and liquid equilibria in porous media." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21323.
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The alteration of the vapor and liquid equilibrium (VLE) of volatile organic mixtures by using porous media at the liquid-vapor interface was studied. Kelvin, assuming ideal behavior of fluids, first introduced the vapor pressure of liquid over a meniscus as a function of its surface tension and the radius of the curvature. A thermodynamic model (SSmod model) predicting the VLE of non-ideal organic mixtures in porous media was developed as a function of pore sizes based on the pressure equations available in literature. The model was used to predict the VLE of two aqueous alcohol solutions, ethanol-water and propanol-water, and two binary alcohol solutions, methanol-isopropanol and ethanol-octane. Experiments were conducted using sintered metal and fritted glass plates as porous media and compared with the model predictions. The model predictions for the actual pore diameters tested showed good agreement with the experimental results.
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Monser, Lotfi Ibrahim. "Modified porous graphitic carbon for liquid chromatography." Thesis, University of Hull, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318379.
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Russo, Ann. "Immiscible Liquid Dissolution in Heterogeneous Porous Media." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/194522.
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Immiscible liquids, including chlorinated solvents, have proven to be a lasting source of subsurface contamination at many hazardous waste sites. Continued improvement of site characterization and determination of applicable remediation technologies can be achieved by further understanding of the transport and fate of these contaminants. The transport and fate of trichloroethene (TCE) was investigated through miscible displacement and dissolution experiments. Miscible displacement experiments were conducted using homogeneously packed columns with several porous media encompassing a range of particle size distributions. Immiscible liquid dissolution was investigated using homogeneously packed columns containing a residual saturation of trichloroethene. The same porous media were used for immiscible liquid dissolution experiments. Mathematical modeling of miscible displacement and dissolution experiments was conducted using a one-dimensional single region or multi-region model. Imaging of immiscible liquid dissolution was also conducted, using Synchrotron X-ray Microtomography imaging at Argonne National Laboratory, Argonne, IL. Dissolution experiments exhibited nonideal dissolution behavior that was apparent in observed effluent data and in collected imaging data. Nonideal behavior was manifested as secondary regions of relatively constant aqueous concentrations occurring for a number of pore volumes. This behavior was observed to increase in magnitude as particle size distribution of the porous media increased. During imaging, immiscible liquid blobs were observed to dissolve throughout the column during dissolution. This behavior is also indicative of nonideal dissolution, as it would be expected that dissolution would first occur for the blobs nearest the inlet and then proceed upward through the column as dissolution progressed. In many cases, a multi-region modeling approach was necessary to successfully represent the nonideal behavior observed. Comparisons were made between the natural porous media used for this research and a well-sorted sand. Nonideal dissolution was not observed in the well-sorted sand.
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Guo, Tianle. "Effects of buoyancy forces on miscible liquid-liquid displacements in porous media." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6825.
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The effects of gravity forces on the miscible displacement of one fluid (aqueous glycerol solution) by another fluid (pure water) in a vertical consolidated porous medium have been investigated. A set of horizontal displacement experiments was performed for comparison with two sets of vertical-upward and vertical-downward displacements. It was found that gravitational forces (i.e. buoyancy forces) can be an important factor in determining the displacement pattern where fluids having different densities and different flowrates are involved. In a given porous medium system, the principal variables which affect the displacement efficiency of oil (or any other miscible liquid) by water are the viscosity ratio, density difference, and displacement flowrate. Increasing the viscosity ratio will decrease the oil recovery; however, when the viscosity ratio is close to unity, good oil recovery will be obtained. The injection flowrate is also critical. At low injection flowrates, the effects of gravity become relatively more important. At high flowrates, gravity forces have less effect on the displacement efficiency. In vertical-upward displacements, buoyancy forces play a negative role since they tend to promote viscous fingering and consequently lower the oil recovery (when $\rm \rho\sb{oil}>\rho\sb{water}$). On the other hand, in vertical-downward displacements, buoyancy forces tend to stabilize the displacement process, and high oil recoveries can be obtained. Comparing the horizontal displacement patterns with those of the two vertical displacements, it was found that buoyancy forces can exert very significant effects on fingering phenomena.
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Zhdanov, Sergey. "Kinetics of spreading over porous substrate." Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/33884.
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The spreading of small liquid drops over thin and thick porous layers (dry or saturated with the same liquid) has been investigated in the case of both complete wetting (silicone oils of different viscosities) and partial wetting (aqueous SDS solutions of different concentrations). Consideration has been carried out from both experimental and theoretical points of view. Nitrocellulose membranes of different porosity and averaged pore size were used as a model of thin porous layers, glass and metal filters were used as a model of thick porous substrates. It has been shown, that the spreading process follows the power law in time in the case of spreading of silicon oil drops over porous substrate saturated with the same oil. The liquid flow in the spreading drop has been matched with the flow in the porous substrate. Both the exponent and the pre-exponential factor of the power law have been predicted and compared with our experimental data, which shows the good agreement. An effective lubrication coefficient has been introduced, which accounts for an effective slippage of liquids over porous substrates. This coefficient has been both theoretically predicted and experimentally verified.
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Pourmand, Payam. "NMR detection of liquid dynamics in porous matrices." Thesis, KTH, Skolan för kemivetenskap (CHE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145864.
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Porous materials or a porous media can be encountered in our everyday life, both in industrial and household systems and in the nature. Generally speaking all solid and semisolid materials are porous to some degree e.g. different dense rock types, plastics etc. Porous materials are constantly finding more and more applications, both in industry and research. Many commercially important process in the industry utilize porous media e.g. flow of fluids through porous media for separation process and porous catalyst supports. This has strongly contributed to the development of porous media with controlled properties, which can be utilized for understanding the behavior of liquids confined in the material, and the morphology of these synthetic materials. This thesis work brings some insight and understanding of porous materials i.e. Controlled Pore Glass (CPG). Report also contains a brief explanation of Nuclear Magnetic Resonance (NMR) spectroscopy, diffusion NMR and other techniques such as Mercury porosimetry. The first part of the thesis is focused on determining the required amount of liquid i.e. octanol needed to achieve full pore saturation for different CPGs with varying pore sizes. This was achieved by taking into account that the transverse relaxation time T2 is sensitive in the ms-ns of motional correlation times, and that there are physical factors in porous material which affect the T2. Second part, diffusion NMR is used to study self-diffusion of octanol confined in CPG, thus bringing some insight on mass transfer limitations within porous systems. The report present results obtained from experiments with NMR and Diffusion NMR, discusses the issues that can arise when investigating porous materials and suggest solutions
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Dias, H. "Gas and liquid chromatography on porous graphitic carbon." Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/13643.
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A new hydrophobic support material, Porous Graphitic (or Graphitised) Carbon (PGC) has been studied using both Liquid (LC) and Gas Chromatography (GC). The heat of adsorbtion (AH) of typical LC solvents determined on PGC, using GC, showed that AH increased with the molecular area (Ax) of solvents for well graphitised carbons, but that AH/Ax values were similar for all solvents studied. By definition, AH/Ax is a measure of eluotropic strength. The results reveal that a strong eluotropic series does not exist on carbon. A strong eluotropic series does exist on silica. In this case, AH/Ax values of solvents were dependent upon their eluotropic strengths (Eo), determined by LC. GC work was carried out using alcohols, ketones and aliphatic hydrocarbons on PGC, modified with different amounts of Carbowax 1500. Symmetrical peaks were obtained with coated materials. The column efficiency (N), first increased and then dropped with increasing Carbowax content on the PGC surface. The retention of ketones and hydrocarbons decreased with increasing amount of Carbowax on PGC. In the case of alcohols, the retention decreased with the initial introduction of Carbowax on to PGC. Some alcohols displayed enhanced retention at 0.10% of Carbowax. All alcohols showed increased retention at the monolayer coverage of Carbowax. In the quest for a perfect material for adsorption GC, PGC samples were hydrogen treated at elevated temperatures (230-1030°C). All hydrogen treated samples failed to display signficantly improved chromatographic properties. PGC was then treated with toluene in a stream of either hydrogen (at 630°C) or nitrogen (at 630°C or 300°C) to eliminate any active sites present on the surface. Hexane was used us an alternative to toluene at 630°C in a stream of hydrogen. Such surface treatments yielded improved materials for adsorption GC. On heating the columns (beyond 230"C), containing these materials, with carrier gas running through the columns, the Chromatography deteriorated in the cases of toluene-treated PGC whilst the Chromatography of the hexane-treatcd PGC remained unaffected. LC work on some aromatic compounds using PGC, coated with surfactants such as Tween 80 or Span 80 showed that, analyte retention decreased with increasing surfactant concentration (up to 0.03% of Tween and 0.02% of Span) in the eluent. N dropped with the introduction of Tween to the PGC. Increasing the ratio of water to mcthanol in the eluent, at a constant eluent concentration of surfactant, resulted in diminishing N, increasing eluent polarity and analyte retention values. Ion pairing was carried out on PGC using cetyltrimethylammonium-bromide (CTAB) as the ion pairing agent, at an eluent pH of 12.5. The retention of solutes, that ionise under these conditions, increased whereas the retention of analytes, that do not ionise, decreased with increasing eluent concentration of CTAB. The coated or chemically modified PGC surfaces are useful in GC whilst the dynamically coated PGC surfaces are important in LC. Such surface treatments can alter the following properties of PGC; (a) Retention characteristics, (b) the selectivity and (c) chromatographic efficiency.
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Wan, Quian-Hong. "Surface modification of porous graphite for liquid chromatography." Thesis, University of Edinburgh, 1992. http://hdl.handle.net/1842/13187.
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Surface modification of porous graphite has been studied in detail by liquid chromatography. The non-polar nature of the graphite provides the basis for adsorptive modification by which the graphite surface is either deactivated or functionized. While the elimination of geometric heterogeneity is achieved by adsorption of trace polyaromatic compounds, the specialist in selectivity is conferred to the graphite by a monolayer coating of modifiers. A number of strategies are used for different purposes. These include dynamic coating, insoluble coating and cross-linked coating. The chromatographic properties of the modified materials are evaluated in terms of efficiency, selectivity and stability. With the exception for cross-linked coating, the modified materials show performances better than those of the original graphite. Applications to adsorption, ion exchange, chiral and exclusion chromatography are demonstrated. These new packings are found particularly useful in the separation of inorganic anions, amino acid and hydroxy acid enantiomers. They give excellent peak symmetry and long term stability. The mechanisms of retention on the graphite based materials are characterised and discussed.
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Tran, Kien Nguyen. "Modelling of vapour-liquid phase equilibrium and adsorptions on non-porous and porous carbon /." St. Lucia, Qld., 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17383.pdf.
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Damronglerd, Piyasak Zhang Yuwen. "Infiltration and solid-liquid phase change in porous media." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6143.
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Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 17, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Dr. Yuwen Zhang. Vita. Includes bibliographical references.
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Al-Saffar, H. B. S. "Fluid flow through porous media : liquid distribution and mass transfer." Thesis, Swansea University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.635715.
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This work presents the results of an experimental study of liquid distribution with counter-current gas flow and without gas flow, carried out in a 0.3m diameter and 1.5m long perspex column packed randomly with 1" plastic Pall rings, 1" plastic Intalox saddles, No.25 Intalox Metal Tower Packing(IMTP) and No.1 metal Nutter rings, in separate experimental sets. The measurements were carried out using concentric annular collectors, in order to measure the distribution of liquid and to distribute the gas uniformly across the bottom of the column. The column was operated with gas flowrates varying over the range of 0 to 1 kg/m2.sec, and liquid flowrates varying over the range of 40 to 80 1/min. Packing height was increased by adding successive layers of packing, while the ratio of the flow supplied to the bulk and wall regions was varied throughout the experiments. The experimental results were analyzed and compared to a theoretical model developed by Gunn(1978) and extended in 1991. Two regions of packing of different permeabilities may be distinguished, the bulk region and an annular region of packing adjacent to the wall and of higher permeability. The wall region was confined to the order of one particle diameter while the remaining cross-section of the column was accounted as the bulk region. The separation of volumetric mass transfer coefficients in packed columns into mass transfer coefficients and specific surface area, has been attempted using the available data on mass transfer presented by various investigators. One aim of this work is to provide a generalized correlation for mass transfer coefficients and interfacial area that characterized the mass transfer performance of various packings that may be used for designing or scaling up columns or reactors.
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GLADDING, SARAH M. "POROUS INORGANIC SUPPORTED LIQUID MEMBRANES FOR USE IN ION CHANNELING." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1109343185.
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Palakurthi, Nikhil Kumar. "Direct Numerical Simulation of Liquid Transport Through Fibrous Porous Media." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406881191.
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Coleman, Nicholas Richard Boldero. "Direct liquid crystal templating of mesoporous silica and platinum." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302011.
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Törnkvist, Anna. "Aspects of porous graphitic carbon as packing material in capillary liquid chromatography /." Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3306.
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Pastore, Andrea. "Syngas production from heavy liquid fuel reforming in inert porous media." Thesis, University of Cambridge, 2010. https://www.repository.cam.ac.uk/handle/1810/237704.
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In the effort to introduce fuel cell technology in the field of decentralized and mobile power generators, a hydrocarbon reformer to syngas seems to be the way for the market uptake. In this thesis, a potential technology is developed and investigated, in order to convert commercial liquid fuel (diesel, kerosene and biodiesel) to syngas. The fundamental concept is to oxidise the fuel in a oxygen depleted environment, obtaining hydrogen and carbon monoxide as main products of the reaction. In order to extend the flammability limit of hydrocarbon/air mixtures, the rich combustion experiments have been carried out in a two-layer porous medium combustor, which stabilises a flame at the matrix interface and recirculates the enthalpy of the hot products in order to enhance the reaction rates at ultra-rich equivalence ratio. This thesis demonstrates the feasibility of the concept, by exploring characteristic parameters for a compact, reliable and cost effective device. Specifically, a range of equivalence ratios, thermal loads and porous materials have been examined. n-heptane was successfully reformed up to an equivalence ratio of 3, reaching a conversion efficiency (based on the lower heating value of H2 and CO over the fuel input) up to 75% for a packed bed of alumina beads. Thermal loads from P=2 to 12 kW at phi=2.0 demonstrated that heat losses can be reduced to 10%.Similarly, diesel, kerosene and bio-diesel were reformed to syngas in a Zirconia foam burner with conversion efficiency over 60%. The effect of different burners, thermal loads and equivalence ratios have also been assessed for these commercial fuels, leading to equivalent conclusions. A preliminary attempt to reduce the content of CO and hydrocarbons in the reformate has been also performed using commercial steam reforming and water-gas shift reaction catalysts, obtaining encouraging results. Finally, soot emission has been assessed, demonstrating particle formation for all the fuels above phi=2.0, with biodiesel showingthe lowest soot formation tendency among all the fuels tested.
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Whelan, Michael P. "Dissolution of non-aqueous phase liquid pools in saturated porous media." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/20140.
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Nikolopoulos, Panagiotis. "Mass transfer in non-aqueous phase liquid contaminated heterogeneous porous media." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611535.
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Kaur, Bulvinder. "Porous graphitic carbon : a new material for high performance liquid chromatography." Thesis, University of Edinburgh, 1986. http://hdl.handle.net/1842/12218.
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This thesis is divided into four parts. In the first part, the history of chromatography is described. Different modes of chromatography are briefly discussed and a survey of stationary phases being used in High Performance Liquid Chromatography (HPLC) is made. The need for a non-polar reversed-phase stationary phase is highlighted. A brief survey of the use of carbon by other workers in liquid chromatography is also made. The second part of the thesis deals with the production and structural study of porous graphitic carbon (PGC). the different stages of production of PGC are discussed. Pore volume and surface area studies on PGC have also been made. A detailed structural study of PGC has been presented. The third part of the thesis deals with the literature survey of the formation of surface complexes on carbon and the gas reactions of carbon, an understanding of which was necessary for the production and control of the final quality of PGC. The fourth part of the thesis deals with the use of PGC in HPLC. A packing method for PGC has been investigated. Different batches of PGC's produced have been tested with standard test solutes. A separation of a wide variety of solutes, including polymethylphenols, polymethylbenzenes, alkylbenzenes, bases, acids, polyaromatic hydrocarbons, pheynl ketones and phthalates on PGC have been achieved. Analgesics can also be separated. Solvent strengths on PGC have been investigated using different solvents and different solutes.
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Kuzmich, A. G., D. A. Andrusenko, P. A. Teselko, M. V. Isaiev, and R. M. Burbelo. "Examination of Thermally Induced Deformations of Composite System “Porous Silicon – Liquid”." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35171.
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In the paper results of analyze of the pressures that appeared in composite system “porous silicon –
liquid” under its heating is presented. The value of thermally induced pressures of liquid in the pores from
photoacoustic measurement was estimate. The temperature dependence of pressures that occurred by interaction
forces between solid matrixes and liquids was experimentally measurement. The values of these
two pressures where compared.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35171
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Oladyshkin, Sergey. "Découplage de la thermodynamique et hydrodynamique et solutions asymptotiques des problèmes d'écoulement compositionnel gaz-liquide en milieux poreux." Thesis, Vandoeuvre-les-Nancy, INPL, 2006. http://www.theses.fr/2006INPL059N/document.
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Le travail actuel traite le problème de l'écoulement gaz-liquide compositionnel pour la représentation d'un puits dans des simulations de réservoir. L'objectif est de développer les rapports analytiques qui pourraient lier la pression de puits, la saturation et les concentrations de composant à leurs valeurs moyennes dans chaque zone de l'influence de puits. Nous avons montre que des N-2 équations décrivant le transport des concentrations de phase peuvent être transformées en équations ordinaires (différentiation en ce qui concerne la pression) indépendantes du temps et de l'espace examinant le long des lignes de courant. Ces équations transformées représentent des relations thermodynamiques additionnelles réduisant le degré de liberté thermodynamique. En raison de ceci le variance thermodynamique du modèle compositionnel limite s'avère égal à 1 pour tout nombre de composants chimiques. Cette transformation assurent se découplage total du modèle compositionnel limite dans le nouveau modèle thermodynamique et le modèle hydrodynamique, qui peut être resoved inedpendently d'un un autre. Le modèle thermodynamique décompose est totalement indépendant sur l'hydrodynamique, et décrit le comportement d'équilibre d'un système gaz-liquide ouvert. Ce modèle contient les équations d'équilibre et la EOS classiques, aussi bien que les N-2 nouvelles équations appelées la "Delta-loi", qui déterminent la variation de composition d'un système ouvert dans lequel la masse de chaque composant n'est pas conservée. Le modèle hydrodynamique décompose a été utiliser pour développer les solutions asymptotiques des problèmes d'écoulement de gaz-condensat. Le problème a été montré perturbé singulièrement avec la formation d'une couche limite à voisinage du puits. Dans cette couche la propriété basique de contraste des mobilities de gaz et de liquide est perturbée. On développe une technique spéciale qui permet de construire des expansions asymptotiques sous forme de deux diverses séries: le primer est valide loin du puits (l'expansion extérieure), alors que le second dans valide à voisinage du puits (la couche limite ou l'expansion intérieure). En appliquant la méthode asymptotique suggérée, nous avons développé les solutions asymptotiques pour le problème de l'écoulement multicompositionnel de gaz-condensat àu puits dans un domaine borné à un débit variable. En plusieurs cas la solution peut être obtenue sous la forme analytique, alors qu'en cas général de l'écoulement la méthode mène à une solution de semi-analytical, présentée comme problème initial pour une équation. Cette solution, même étant présenté en forme non-analytique, est beaucoup plus simple que le modèle compositionnel original, car l'équation pour la saturation ne dépend pas de la pression locale, mais dépend de la pression de bord seulement. Dans le dernier chapitre nous avons prolongé cette approche au cas quand la pression capillaire n'est pas négligée. Nous avons supposé cependant que les forces capillaires sont inférieures à la différence de pression entre le puits et la bord de réservoir, dus à ce que nous avons appliqué la méthode de perturbation pour petit nombre capillaire inverse. On obtient les solutions asymptotiques améliorées qui tiennent compte de l'effet capillaire. Simulations numériques montrées que ces effets sont maximaux àu voisinage du puits. Le cas d'une exploitation à long terme du réservoir. Tout d'abord, la simulation traditionnelle du comportement de réservoir peut être effectuée avec l'ECLIPSE en ajoutant la méthode de Peaceman de représentation bonne, qui est une relation analytique pour la pression de puits par l'intermédiaire du débit de production. Cette relation inclut une saturation condensat qui peut être évaluée comme saturation moyenne de réservoir. Une telle simulation fournit un bon résultat pour la pression de puits (ou le débit de production), et un bon résultat pour la saturation de bord, mais des données faibles pour la saturation de puits. Cette valeur peut être calculée en utilisant les solutions asymptotiques suggérées dans le présent projet. Le cas d'un puits de production à court terme (un essai de puits). Il est suffisant de simuler le comportement de réservoir dans le domaine de l'influence de puits, en supposant que l'état de frontière demeure invariable (et connu a priori). Dans ce cas-ci les solutions asymptotiques suggérées dans le travail de presnet peuvent être directement employées pour simuler le problème (sans employer l'ECLIPSE). Le problème de l'écoulement de gaz-condensat à une fracture. Nous avons construit un champ plutôt arbitraire avec des lignes de courant orientées à la fracture, en supposant que la fracture joue le rôle d'une décharge, et les lignes de courant sont stationnaire. Pour une ligne de courant arbitraire nous avons reformulé le modèle d'écoulement de gaz-condensat dans des coordonnées cartésiennes. Pour ce problème nous avons développé les expansions asymptotiquesThe present work deals with the problem of the compositional gas-liquid flow for the well representation in reservoir simulations. The objective is to develop analytical relationships which would be able to link the wellbore pressure, saturation and component concentrations to their mean values within each zone of the well influence. It is shown that N-2 equations describing the transport of phase concentrations can be transformed into the space- and time-independent ordinary differential equations (differentiation with respect to pressure) when examined along flow streamlines. These transformed equations represent additional thermodynamic relations reducing the thermodynamic degree of freedom. Due to this the thermodynamic variance of the limit compositional model is shown to be equal to 1 for any number of chemical components. This transformation ensure a total splitting of the limit compositional model into the new thermodynamic model and a hydrodynamic model, which may be resoved inedpendently of one another. The split thermodynamic model is totally independent on the hydrodynamic one, and describes the equilibrium behaviour of an open gas-liquid system. This model contains the classic equilibrium equations and EOS, as well as N-2 new differential equations called the "delta-law" which determine the composition variation in an open system, in which the mass of each component is not conserved. The split hydrodynamic model consists of two equations for pressure and saturation. The split hydrodynamic model was used to develop asymptotic solutions of gas-condensate flow problems. The problem was shown to be singularly perturbed with formation of a boundary layer in the vicinity of the well. In this layer the basic contrast property of gas and liquid mobilities is perturbed. A special technique is developed which enables to construct asymptotic expansions in the form of two various series, one of them is valid far from the well (the exterior expansion), while the second one in valid in the vicinity of the well (the boundary-layer or interior expansion). By applying the suggested asymptotic method, we have developed the asymptotic solutions for the problem of multi-component gas-condensate flow to a well in a bounded domain at a variable flow rate. In several cases the solution may be obtained in the analytical form, while in general case of flow the method leads to a semi-analytical solution presented as an initial problem for a differential equation. This solution, even being presented in non-analytical form, is much simpler than the original compositional model, as the equation for saturation does not depend on the local pressure, but on the boundary pressure only. In the last chapter we extended this approach to the case when the capillary pressure is not neglected. We assumed however that the capillary forces are lower than the pressure difference between the wellbore and reservoir boundary, due to which we applied the perturbation method over the small inverse capillary number. The improved asymptotic solutions are obtained which take into account the capillary effect. Numerical simulations shown that these effects are maximal in the vicinity of the well. For the practice, the obtained asymptotic solutions may be used in the following way to resolve the problem of gas-condensate well representation. The case of a long-term exploitation of the reservoir}. First of all, the traditional simulation of the reservoir behaviour can be performed with ECLIPSE by adding the Peaceman method of well representation, which is an analytical relation for the wellbore pressure via the production rate. This relation includes a condensate saturation which can be evaluated as a mean reservoir saturation. Such a simulation provides a good result for the wellbore pressure (or the production rate), and a good result for the boundary saturation, but poor data for the wellbore saturation. This value can be calculated next by using the asymptotic solutions suggested in the presented project. The case of a short-term well production (a well test). It is sufficient to simulate the reservoir behaviour in the domain of the well influence, by assuming that the boundary state remains invariable (and known a priori). In this case the asymptotic solutions suggested in the presnet work can be directly used to simulate the problem (without using ECLIPSE)
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Nguyen, Khac Long. "Multiscale analysis of transport in porous media." Thesis, Aix-Marseille, 2019. http://theses.univ-amu.fr.lama.univ-amu.fr/190522_NGUYEN_156sqbpnr595zlxet195ycj854nvqyn_TH.pdf.
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La corrélation entre les propriétés structurales des matériaux et les propriétés de transport d’un fluide à travers les matériaux poreux intervient dans de nombreux procédés en physique, chimie, géologie et ingénierie. Les propriétés telles que la porosité et la distribution de taille de pore ne reflètent pas la complexité du réseau poreux qui consiste en un réseau de pores interconnectés irrégulier et de différentes sections. La complexité est décrite par un paramètre appelé la tortuosité. La tortuosité est déterminé par des mesures électriques ou par chromatographie liquide. En chromatographie liquide la tortuosité intraparticulaire est calculée à partir du coefficient de diffusion intraparticulaire de polystyrènes déterminé à partir de l’élargissement des pics obtenus en mode dynamique et en mode statique en conditions non-adsorbantes avec le solvant tétrahydrofurane (THF). En mode dynamique, dans l’équation de van Deemter, le terme constant dépend de la diffusion d’eddy et de la polydispersité des polystyrènes. La silice poreuse Si100 présente une distribution de taille des pores assez large ce qui entraîne l’élargissement des pics chromatographiques. Le transport de polystyrènes à travers les silices en conditions adsorbantes a également été étudié en modifiant le solvant. En conditions adsorbantes, avec un mélange de THF et d’heptane, pour un polymère de taille donné, plusieurs pics sont obtenus en raison de la polydispersité du polystyrène. L’adsorption augmente avec la masse molaire du polystyrène. La diffusion de surface diminue lorsque le facteur de rétention augmenteThe correlation of the structural parameters with the transfer properties of a fluid through a porous media is a significant subject in physics, chemistry, geology, and engineering. The architectural parameters such as porosity and pore size distribution do not describe the complexity of most porous organizations consisting of labyrinths of interconnected pores with random shapes and cross-sections. This complexity is described by a parameter called tortuosity. The apparent total and particle tortuosities are determined by electrical measurements or the analysis of the peak shape of chromatographic probes. In the latter case, the particle tortuosity of silica is calculated from effective intraparticle diffusion coefficient determined by modelling the chromatographic peak broadening of polystyrenes obtained either in dynamic or in static conditions under non-adsorbing conditions by using the solvent tetrahydrofuran (THF). In dynamic conditions, the constant term in the van Deemter equation is a combined contribution of eddy diffusion and polydispersity of the polystyrenes and depends on the size of the molecule. The broad pore size distribution of totally porous silica contributes also to the spreading of the peak. The transport of polystyrenes through silica columns has also been studied in adsorbing conditions by changing the solvent. With the mixture of n-Heptane and THF, one obtains many peaks for a polystyrene sample due to the polydispersity of the polystyrene. In fact, the adsorption increases with the molecular weight of the polystyrenes. The surface diffusion of polystyrene decreases with an increase in the retention factor
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Swan, Geoffrey Ian. "Structural studies of formic acid and water in porous silica by neutron diffraction." Thesis, University of Kent, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328234.
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Hemming, Ellen. "Exploring the application of porous and ionic liquids for sustainable chemistry." Thesis, The University of Sydney, 2019. https://hdl.handle.net/2123/22103.
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Porous liquids are a new class of materials, which have predominantly been investigated for their capacity to adsorb gases. However, these materials are expected to possess unusual combinations of characteristics, typically associated either with porous solids or with liquids, leading to, as yet, unexplored applications. This thesis explored the encapsulation of catalysts within porous liquids and their resulting catalytic activities. The encapsulation of metal nanoparticles within a Type I porous liquid was explored first. This involved the encapsulation of the nanoparticles within the hollow silica spheres before functionalisation with a corona-canopy to form the porous liquid. The methodology developed was successfully employed for the encapsulation of gold, platinum and palladium nanoparticles. The catalytic activity of the platinum nanoparticles encapsulated within the porous liquid was then investigated as a hydrogenation catalyst under mild conditions. The effect of each component of the porous liquid was explored in order to advance the understanding of the fundamental catalytic properties of porous liquids. Further exploring these systems, the immobilisation of a homogeneous catalyst within the cavities of the porous liquid was investigated. A palladium-based complex was covalently tethered to the silica spheres before functionalisation with the corona-canopy, immobilising this homogeneous catalyst within the porous liquid. This porous liquid system was successfully employed as a catalyst for Heck reactions. The final aspect of this thesis was to explore greener alternatives to the current methodologies for the synthesis of N,N,N-trimethyl chitosan, which has gained much interest for its prospective industrial and pharmaceutical applications. Conventional methods for the methylation of chitosan involve the use of highly toxic reagents. A method was developed for the single-step methylation using dimethyl carbonate, a green methylating agent.
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Guo, Tianle. "Experimental and theoretical studies of the effects of buoyancy forces on liquid/liquid displacement processes in porous media." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq26121.pdf.
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Törnkvist, Anna. "Aspects of Porous Graphitic Carbon as Packing Material in Capillary Liquid Chromatography." Doctoral thesis, Uppsala University, Analytical Chemistry, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3306.
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In this thesis, porous graphitic carbon (PGC) has been used as packing material in packed capillary liquid chromatography. The unique chromatographic properties of PGC has been studied in some detail and applied to different analytical challenges using both electrospray ionization-mass spectrometry (ESI-MS) and ultra violet (UV) absorbance detection.
The crucial importance of disengaging the conductive PGC chromatographic separation media from the high voltage mass spectrometric interface has been shown. In the absence of a grounded point between the column and ESI emitter, a current through the column was present, and changed retention behaviors for 3-O-methyl-DOPA and tyrosine were observed. An alteration of the chromatographic properties was also seen when PGC was chemically oxidized with permanganate, possibly due to an oxidation of the few surface groups present on the PGC material.
The dynamic adsorption of the chiral selector lasalocid onto the PGC support resulted in a useful and stable chiral stationary phase. Extraordinary enantioselectivity was observed for 1-(1-naphthyl)ethylamine, and enantioseparation was also achieved for other amines, amino acids, acids and alcohols.
Finally, a new strategy for separation of small biologically active compounds in plasma and brain tissue has been developed. With PGC as stationary phase it was possible to utilize a mobile phase of high content of organic modifier, without the addition of ion-pairing agents, and still selectively separate the analytes.
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Richardson, David Jeremy. "Enhanced mass transport in liquid-saturated porous media due to surface shear." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/27112.
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The principal aim of this work was the development of a novel conductivity probe for measuring solids concentrations in slurries. The relevance of the thesis to this probe is that it requires rapid transport of aqueous electrolyte through a porous disc to an internal conductivity cell.
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Johns, M. L. "MRI studies and modelling of two phase-liquid systems in porous media." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.605617.
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Hydrocarbon ganglia, trapped in the pore space of a ballotini packing by capillary forces, were selectively imaged using MRI. The geometric characteristics of these ganglia were monitored as they dissolved into a surrounding mobile aqueous phase. In particular the surface area of the ganglia was quantified during the course of dissolution. This was then included into a one-dimensional advection-dispersion model of the ganglia dissolution process, which contained only one free parameter, the mass transfer coefficient. The model predicted the experimental data reasonably well, but tended to over-predict dissolution after long time periods. Heterogeneity in pore-scale flow was identified as an explanation for this. The one-dimensional model was extended to systems composed of smaller packing material where imaging of the ganglia was no longer possible. The surface area of the ganglia was quantified by monitoring the diffusion of the hydrocarbon molecules inside the ganglia using pulsed field gradient nuclear magnetic resonance. An alternative three-dimensional model of the dissolution process was developed based on the used of cellular automata. Three-dimensional velocity images of the mobile aqueous phase surrounding the dissolving ganglia were acquired using MRI, and included into this modelling approach. Ganglia formation following an imbibition process, in which water displaced the hydrocarbon from the pore space of the packing, was also investigated using MRI. the results of this experimental investigation were compared with those produced by application of an invasion percolation model to a pore network representation of the pore space. Reasonable agreement between the experimental data and this modelling approach was produced. This pore network was generated using a pore thinning algorithm which segments the pore space into individual pores. An evaluation of this algorithm using different packing structures was also performed.
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Ardelean, Ioan, German Farrher, Carlos Mattea, and Rainer Kimmich. "From "fast" to "slow" liquid-vapor exchange in partially filled porous media." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-194922.
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Saito, Haruko. "Formation Process and Liquid Transport of Sol-gel Derived Monolithic Porous Silica." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/57273.
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Hippauf, Felix. "Tailoring Pore Size and Polarity for Liquid Phase Adsorption by Porous Carbons." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-223482.
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Adsorption is a versatile purification technique to selectively separate different peptide fractions from a mixture using mild operation conditions. Porous carbons are ideally suited to separate ACE-inhibiting dipeptides by combining tailored size exclusion and polarity selectivity. The desired peptide fraction is mostly hydrophobic and very small and should adsorb inside hydrophobic micropores.
The second topic of this thesis is linked to energy storage. The lithium-sulfur battery is a promising alternative to common lithium-ion batteries with theoretical capacities of up to 1672 mAh g−1 sulfur. The second aim of this thesis is to conduct an in-depth investigation of polysulfides interacting with selected carbon materials in a simplified battery electrolyte environment. The focus of this study is laid on the impact of surface polarity and pore size distribution of the carbon to develop a quantitative correlation between polysulfide retention and porosity metrics.
Both, the enrichment of ACE-inhibitors and the retention of polysulfides rely on liquid phase adsorption in porous materials, linking the above mentioned topics. This thesis not only aims to develop an enrichment process or to find a superior battery cathode but also strives to explore structure-property relationships that are universally valid. Understanding the complex interplay of pore size and polarity leading to selective interactions between pore wall and the adsorbed species is given a high priority.
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Pizzoccaro, Marie-Alix. "Confinement et greffage de liquides ioniques dans des membranes céramiques mésoporeuses pour le transport sélectif du CO2." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS007/document.
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En compétition avec les alcanolamines, les liquides ioniques (LIs) sont connus pour interagir fortement et de façon réversible avec des gaz acides. Les propriétés remarquables des LIs ont conduit à la réalisation de ‘Supported Ionic Liquid Membranes’ (SILMs) qui sont des systèmes continus attractifs pour la séparation de gaz, et notamment du CO2. Dans les SILMs, il est possible d’adapter les propriétés d'adsorption/séparation en modifiant les caractéristiques du support (e.g. composition, structure poreuse, surface spécifique, etc.) et du LI (nature des cations et anions). En dépit de leur relative instabilité dans les procédés de séparation de gaz acides, les supports nanoporeux polymériques sont classiquement utilisés pour préparer des SILMs. Récemment, les supports céramiques poreux ont été considérés pour la réalisation de SILMs en raison de leurs excellentes résistances thermique et mécanique. La plupart de ces systèmes sont préparés par imprégnation/infiltration des LIs dans les pores du support céramique. Ce protocole conduit à la formation de matériaux composites dans lesquels le LI est physiquement piégé dans le support, mais souvent avec une distribution hétérogène du LI et une stabilité limitée dans le temps. Dans ce travail de thèse, réalisé en collaboration entre l’Institut Européen des Membranes (IEM) et l’Institut Charles Gerhardt de Montpellier (ICGM), nous avons développé une nouvelle génération de SILMs, dans lesquelles le LI est confiné dans les pores d'un support en céramique mésoporeux par greffage chimique. La préparation de ces systèmes se fait en trois étapes :i) Synthèse et caractérisation de nouveaux LIs portant des fonctions de couplage pour assurer leur greffage en surface des pores de la membrane céramique et détermination de la capacité d’absorption du CO2 des différents LIs synthétisés;ii) Optimisation des paramètres de greffage de ces LIs sur des poudres modèles de γ-Al2O3 et caractérisation des matériaux hybrides obtenus avec mise en évidence du greffage;iii) Transfert du protocole de greffage optimisé sur des membranes céramiques commerciales γ-alumine (fabrication de Grafted Ionic Liquid Membranes - GILMs) et évaluation de leurs performances pour la séparation du CO2.Ce travail, basé sur une approche originale, associant de nouveaux liquides ioniques et un nouveau concept de membrane à base de liquide ionique supporté, montre, au travers de plusieurs exemples l’intérêt d’une approche multi-étapes pour le développement de systèmes membranaires de séparation du CO2In competition with amines, ionic liquids (ILs) are known to interact strongly and reversibly with acid gases, making supported IL-membrane (SILMs) versatile materials for use in CO2 membrane separation applications. It is possible to finely tune SILMs properties for CO2 adsorption/separation by tailoring the characteristics of both the support (e.g., porosity, surface area, composition, etc.) and the ionic liquid (cations and anions). Up to now, nanoporous polymer supports have been favored for preparing SILMs, in spite of their relative instability during continuous separation processes in the presence of acidic gases. Recently, porous ceramic supports have been considered due to their excellent thermal and mechanical resistance. Most of the SILMs are prepared by impregnation/infiltration of IL in the pores of ceramic support which leads to the formation of composite membrane materials with either a physisorbed or mechanically trapped IL in the support. Despite their promising performance, such SILMs exhibit inherent limitations such as facile IL disarrangement, heterogeneous distribution, and limited stability upon ageing.In this Ph.D work, carried out in collaboration between the Institut Européen des Membranes (IEM) and the Institut Charles Gerhardt de Montpellier (ICGM), a new generation of SILMs has been developed in which ILs are confined within the pores of a mesoporous ceramic support by chemical grafting. The membranes are prepared in three steps:i) Synthesis and characterization of new ILs bearing a coupling function which allow the grafting on the surface of ceramic oxide supports and determination of the CO2 absorption capacity of the new ILs developed;ii) Elaboration and/or optimization of relevant synthesis protocols for grafting ILs on/in γ-alumina powders and physico-chemical characterizations of the hybrid materials;iii) Transfer of the optimized grafting protocols on commercial porous ceramic support with γ-alumina top-layer to produce Grafted Ionic Liquid Membranes (GILMs) and evaluate their performance for CO2 separation.An original research strategy, based on new ionic liquids and innovative membrane concepts have been addressed in this work, illustrating the contribution of a multi-step approach towards the development of membranes for CO2 separation
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Gamero, Rafael. "Mass transfer during isothermal drying of a porous solid containing multicomponent liquid mixtures." Licentiate thesis, KTH, Chemical Engineering and Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1748.
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Mass transfer in a porous solid, partially saturated with asingle solvent and multicomponent liquid mixtures, has beenexperimentally and theoretically studied. A porous materialcontaining single liquids and mixtures of organic solvents wasisothermally dried. Experiments were performed using a jacketedwind tunnel, through which a humidity andtemperature-controlled air stream flowed. The wetted porousmaterial was placed in a cylindrical vessel, whose top isexposed to the air stream until the material became dried to acertain extent. Drying experiments with the single solventswater, methanol, ethanol and 2-propanol, were performed atdifferent temperatures and transient liquid content profileswere determined. In isothermal drying experiments with liquidmixtures,the transient concentration profiles of thecomponents along the cylindrical sample as well as the totalliquid content were determined. The liquid mixtures examinedwere water-methanolethanol and isopropanol-methanol-ethanol.Two different temperatures and initial compositions were usedin the experiments. Mathematical models that describe nonsteadystate isothermal drying of a solid containing single liquidsand multicomponent liquid mixtures were developed. In the solidwetted with a single liquid, capillary movement of the liquidwas the main mechanism responsible for mass transfer. In thesolid containing liquid mixtures, interactive diffusion inliquid phase was superimposed to the capillary movement of theliquid mixture. In addition, interactive diffusion of thevapours in empty pores was considered. The parameters todescribe the retention properties of the solid and thecapillary movement of the liquid were determined by comparingtheoretical and experimental liquid content profiles obtainedduring drying of the solid wetted with single liquids. Tosimulate the transport of the liquid mixtures these parameterswhere weighed according to liquid composition. A fairly goodagreement between theoretical and experimental liquidcomposition profiles was obtained if axial dispersion isincluded in the model when the moisture consists of amixture.
Keywords:Internal mass transfer, capillary flow,multicomponent, diffusion, solvent mixtures
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Harding, S. G. "NMR studies of structure-transport relationships in porous media : liquid diffusion in polymers." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603691.
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The main motivation behind this work was to explore the potential of nuclear magnetic resonance (NMR) to study small molecule diffusion in porous materials and the relationship between structure and transport processes, with particular emphasis on liquid diffusion in polymers. The diffusion of small hydrocarbons into a range of semicrystalline polyethylene (PE) samples is studied. Under the penetration conditions employed the polymer crystallinity is retained, supporting the idea that the penetrant resides only in the amorphous region. Magnetic resonance imaging (MRI) is used to monitor the bulk transport of penetrating liquids into the polymers. Pulsed Gradient Spin Echo (PGSE) NMR is used to measure the self diffusivity of the penetrant. The transport diffusivity estimated from MRI shows good agreement with the self diffusivity when the degree of crystallinity is taken into account. The data presented show the importance of the phase and chain structure of the polymer on the diffusion and mobility of the penetrating species. Deuterium NMR relaxation time and line shape analysis is used to measure the correlation time of various motional process. By comparing the correlation time for translational motion with the PGSE self diffusivity it has been possible to estimate the penetrant jump distance to be in the order of a few nanometers. Molecular Dynamics (MD) simulations of hexane diffusion in amorphous PE are shown to give reasonable agreement with PGSE results. A mesoscopic lattice model is used to include the effect of the impenetrable crystallites on the diffusion process. Preliminary results using 31P NMR spectroscopy to study the mobility and molecular scale distribution of additives show that some additives intimately mixed with the polymer while some reside in a discrete domain of around 100 nm. Diffusion weighted imaging is used to study liquid diffusion into polyethylene oxide (PEO) hydrogel. Despite the diffusion kinetics showing Fickian behaviour the concentration dependence of the diffusivity calculated from the PGSE measurements and from the concentration profiles are significantly different, highlighting the importance of the polymer chains in controlling the diffusion process. Three dimensional imaging shows that structural heterogeneities in catalyst support pellets can be characterised by a fractal parameter. The importance of slice thickness in determining the distribution of T1 times from a 2D image is highlighted. NMR cryoporometry is used to measure the pore size distribution and the results compare well in nitrogen adsorption, and T1 measurements. NMR cryoporometry is combined with MRI and the spatial variations in the pore size distribution are shown to be similar to those previously observed through NMR spin density and relaxation imaging.
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Coslovich, Daniele, Dieter Schwanzer, and Gerhard Kahl. "Diffusion-localization and liquid-glass transitions of a colloidal fluid in porous confinement." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-190390.
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Pham, Quang Nhat. "Fabrication of Copper Inverse Opals for Microscale Liquid Transport in Polycrystalline Porous Media." Thesis, University of California, Irvine, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10828027.
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The continually increasing power density of high-performance electronics is bottlenecked by the challenges faced with thermal management requirements for reliable operation. While the traditional convective air-cooling approach is limited in its effectiveness at dissipating high heat fluxes, the use of latent heat in liquid-vapor phase change is an attractive strategy for managing the most aggressive thermal loading demands. Passive two-phase cooling operates by capillary pumping fluid through void spaces within porous metals to transport energy over long distances. The performance of such liquid delivery through porous structures is governed by the pore distribution, porosity, and morphology. Analogous to energy transport in polycrystalline solids, hydraulic transport in polycrystalline porous media is also limited by structural defects and grain boundaries. This work reports on the capillary performances of both single- and polycrystalline microporous copper with varying pore diameters from 300 to 1000 nm. The hydraulic transport through the arrays of interconnected spherical pores is modeled and quantified with experimental wicking measurements, and the influence of grain boundaries on the hydraulic transport in polycrystalline microporous media contributes to the hydraulic resistance presented by the structural defects. By combining multiple pore diameters and systematically layering them, this study creates heterogeneous porous media to emulate the transport within biological systems. The gradient layering of pores enhances the liquid delivery by circumventing grain boundary defects in three dimensions. The fundamental understanding of hydraulic transport physics through porous crystals and boundaries will pave the way for the spatial design of heterogeneous porous materials for future capillary-driven technologies.
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Coslovich, Daniele, Dieter Schwanzer, and Gerhard Kahl. "Diffusion-localization and liquid-glass transitions of a colloidal fluid in porous confinement." Diffusion fundamentals 11 (2009) 58, S. 1-2, 2009. https://ul.qucosa.de/id/qucosa%3A14023.
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Carroll, Kenneth Cooper. "Characterization, Dissolution, and Enhanced Solubilization of Multicomponent Nonaqueous Phase Liquid in Porous Media." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/195399.
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Multicomponent nonaqueous phase liquids (NAPL) contaminating the subsurface can significantly inhibit remediation. One method of enhancing the rate of remediation of NAPL constituents, compared to pump-and-treat, involves source zone treatment with enhanced solubilization agents (ESAs) including cyclodextrins. Equilibrium cyclodextrin enhanced solubilization of simple 1, 2, and 3 component NAPL mixtures was examined to evaluate the applicability of Raoult's Law. The results suggest that Raoult's Law may be used to estimate equilibrium and early-time dynamic concentrations in contact with ideal NAPL mixtures, and Raoult's Law may be used to estimate cyclodextrin enhanced groundwater concentrations for ideal NAPL mixtures. Solubility enhancement of NAPL compounds was dependent on the cyclodextrin concentration and independent of NAPL composition. Column experiments and numerical modeling were used to evaluate the dissolution behavior of the NAPL mixtures in water and a cyclodextrin solution to estimate mass transfer rates. The aqueous multicomponent dissolution followed Raoult's Law, and the model-estimated lumped rate coefficients were independent of the NAPL composition. Addition of the cyclodextrin enhanced the dissolution and removal of compounds from residual NAPL due to an increase in the driving force (i.e. concentration gradient) and the mass transfer coefficient. The model results suggest that Raoult's Law is applicable for ideal NAPL mixture dissolution in water, but potential nonideality was observed and caused the model simulation to deviate from the dissolution behavior for NAPL mixture cyclodextrin experiments. The cyclodextrin dissolution experiments were less rate-limited than aqueous dissolution, and the mass transfer coefficients were quantified with the model. The results of the model suggest that NAPL mixture nonideality and intra-NAPL diffusion may also impact enhanced dissolution behavior. Additionally, the importance of NAPL mixture characterization was illustrated by evaluation of a mixture of PCE (tetrachloroethene) and diesel fuel collected from a site in Tucson, Arizona. A sample from the site was used to create mixtures with increasing PCE in the NAPL. Chemical evaluation of the complex NAPL was conducted, and physical property and phase partitioning testing was performed, which demonstrated the effect of NAPL composition on its distribution, interphase mass transfer, and potential mobilization.
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Bai, Guiyun 1964. "Biosurfactant-enhanced nonaqueous phase liquid (NAPL) removal and bacterial transport in porous media." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282451.
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The well documented ineffectiveness of traditional pump-and-treat technology on the cleanup of non aqueous phase liquid (NAPL) contaminated sites has incurred an intensive research activities in improving the efficiency of NAPL removal from subsurface. Surfactant enhanced subsurface remediation has been proposed as one such option. In this dissertation, a series laboratory experiments were conducted to investigate the potential application of a microbially produced surfactant (biosurfactant) on NAPL removal and the effect on bacteria transport. Monorhamnolipid biosurfactant, produced by Pseudomonas aeruginosa ATCC 9027, was used in all the studies. Hexadecane was used as model NAPL to represent petroleum based products which are common NAPLs detected in contaminated sites. Results showed that rhamnolipid biosurfactant is effective in removing residual hexadecane from sandy soil. In the surfactant concentration tested in this study (40 to 1500 mg/L), mobilization of hexadecane is the main mechanism of the removal. In addition to displacement of hexadecane droplets from subsurface porous matrixes, dispersion or emulsification of hexadecane into surfactant solution also played an important role in hexadecane removal. The performance of this anionic rhamnolipid surfactant is greatly affected by the addition of electrolytes and the change of pH. Addition of Na⁺ and Mg²⁺ can significantly increase the solubilization capacity of rhamnolipid and reduce the interfacial tension between hexadecane and surfactant solution, while addition of Ca²⁺ has a competing effects of enhanced solubilization and Ca²⁺ induced rhamnolipid precipitation. Control of ionic strength and pH can be used to optimize surfactant systems to enhance the NAPL removal depending on the nature of NAPL (LNAPL or DNAPL). Addition of rhamnolipid can also enhance the transport of three bacterial cells with varying hydrophobicity, P. aeruginosa ATCC 9027, 27853, and 15442, by decreasing cell adsorption. This is because the adsorption of surfactant to the porous medium surface increases the surface negative charge density, hence the adsorption of bacteria to the surface is reduced. No significant influence of rhamnolipid on the bacteria surface properties is observed. The measured bacteria breakthrough curves were simulated by an advection-dispersion transport model incorporating two domain reversible sorption (instantaneous and rate-limited) and with two first order sink terms for irreversible sorption. Model simulation suggests that rhamnolipid mainly affects the irreversible sorption of cells.
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Yien, Linen Ling-Ying. "An investigation into the electro-convective motions of liquid hydrocarbons in porous media." Thesis, University of Bristol, 1992. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333873.
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Tytarenko, A. I., D. A. Andrusenko, M. V. Isaiev, and R. M. Burbelo. "Investigation of Heat Transfer in Nanocomposite Structures “PS-liquid” Using Photoacoustic Method." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35111.
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The thermal properties of porous silicon and composite «PS-liquid» system have been investigated in
this paper. Using the photoacoustic method the values of thermal conductivity of porous silicon and composite
systems with liquid have been obtained. It is shown that the value of thermal conductivity «PS-liquid»
substantially exceeds the value determined by the model of «parallel structures». The increase of thermal
conductivity is due to the improvement of thermal contacts among the crystallites when introducing liquid
into the pores.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35111
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Afonso, Josiana Prado. "Towards cryogenic liquid –vapor energy storage units for space applications." Doctoral thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10158.
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Dissertation to obtain the Doctoral degree
in Physics EngineeringWith the development of mechanical coolers and very sensitive cryogenic sensors, it could be interesting to use Energy Storage Units (ESU) and turn off the cryocooler to operate in a free micro vibration environment. An ESU would also avoid cryogenic systems oversized to attenuate temperature fluctuations due to thermal load variations which is useful particularly for space applications. In both cases, the temperature drift must remain limited to keep good detector performances. In this thesis, ESUs based on the high latent heat associated to liquid-vapor phase change to store energy have been studied. To limit temperature drifts while keeping small size cell at low temperature, a potential solution consists in splitting the ESU in two volumes: a low temperature cell coupled to a cryocooler cold finger through a thermal heat switch and an expansion volume at room temperature to reduce the temperature increase occurring during liquid evaporation. To obtain a vanishing temperature drift, a new improvement has been tested using two-phase nitrogen: a controlled valve was inserted between the two volumes in order to control the cold cell pressure. In addition, a porous material was used inside the cell to turn the ESU gravity independent and suitable for space applications. In this case, experiments reveal not fully understood results concerning both energy storage and liquid-wall temperature difference. To capture the thermal influence of the porous media, a dedicated cell with poorly conductive lateral wall was built and operated with two-phase helium. After its characterization outside the saturation conditions (conduction, convection), experiments were performed, with and without porous media, heating at the top or the bottom of the cell with various heat fluxes and for different saturation temperatures. In parallel, a model describing the thermal response for a cell containing liquid and vapor with a porous medium heated at the top (“against gravity”) was developed. The experimental data were then used as a benchmark for this model based on a balance of three forces: capillarity force, gravity force and pressure drop induced by the liquid flow.
Fundação da Ciência e da Tecnologia - PhD scholarship(SFRH/BD/60357/2009); project “Cryogenic Temperature Stabilizers” (PTDC/EME-MFE/101448/2008)
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Ross, P. "The use of porous graphitic carbon in liquid chromatography performance and polar retention effect." Thesis, University of Edinburgh, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529492.
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This thesis is primarily concerned with the use and development of Porous Graphitic Carbon (PGC) for High Performance Liquid Chromatography (HPLC). Chromatographic studies carried out using PGC since its introduction in 1988 have shown it to posses quite unique separating properties. In particular the media has been shown to be very selective for the separation of closely related compounds such as geometric and diastereoisomers. It has also been shown to be very retentive towards compounds of increasing polarity. The magnitude of this interaction is considerable, we define it as the retention over and above that which might have been predicted if the polar functional group was replaced with a non polar group of similar size. We have called this effect, the Polar Retention Effect on Graphite (PREG). Previous attempts to correlate retention on graphite with energies associated with those molecular interactions associated with other chromatographic media have been largely unsuccessful. This has in part been due to the fact that there has been no attempt to measure in units of energy the magnitude of PREG. The main body of the thesis is then concerned with experiments, which provide information regarding the magnitude of PREG. We investigate a) the relative strength of analyte/graphite interactions to that of analyte/solvent interactions, b) the effect of coating discrete or polymeric molecules to the graphite surface on PREG and c) measure the energy associated with PREG for a range of analytes and correlate this energy with physical and calculated parameters associated with each analyte. In order to gain a measure of PREG we have developed a method which allows PREG to be measured and quantified. Based on our values of PREG we have put forward a hypothesis for the mechanism responsible for this interaction. Further work still needs to be done to strengthen this hypothesis, we therefore put forward a number of ideas and suggestions for future workers to which continue to investigate the mechanism associated with PREG.
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Haeri, Nejad Masoud. "Drying of Porous Particles containing Liquid Mixtures in a Continuous Vibrated Fluid Bed Dryer." Thesis, KTH, Skolan för kemivetenskap (CHE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-156215.
Full textAbstract:
The influence of operation parameters on the drying of spherical porous particles containing a mixture of solvents evaporating into nitrogen in a continuously worked vibrated fluid-bed dryer was studied. A simulation based on the analytical solution to heat and mass transfer equations was applied and modifications were suggested. Four different ternary liquid mixtures were selected: Acetone-Chloroform-Methanol (ACM), Ethanol- 2-propanol-Water (EIpW), Water-Ethanol-Ethyl Acetate (WEEa) and Ethanol-Methylethylketone- Toluene (EMekT). For the solid, physical properties of Pyrex was used. Comparison of composition- and temperature- profiles indicated that there is no resistance against heat transfer within the solid and that the heat transfer is much faster than mass transfer. Selectivity diagrams were drawn. The results indicated that selectivity is an important parameter in predicting the drying behavior. The retention ratio was studied as performance parameter. Its variation was studied in response to changes in operation parameters, including gas velocity and temperature, as well as solid temperature and particle size. A modification to the model was examined by assuming a liquid-content-dependent diffusion resistance factor. It was observed that implementing such an assumption yields decreased values for retention ratios. The effect of vibration on heat and mass transfer coefficients was included using a correlation suggested by Sbrodov and the resulting effect on retention ratio was examined.Inverkan av driftparameter på torkning av sfäriska porösa partiklar som innehåller lösningsmedelblandningar som avdunstar i kväve i en kontinuerligt viberande fluidbädd-tork studerades. En simuleringsmodell baserad på den analytiska lösningen till värme- och materieöverföringsekvationerna användes och ändringar föreslogs. Fyra olika tärnar vätskeblandningar valdes: aceton-kloroform-metanol(ACM), etanol-2- propanolvatten,(EIpW), vatten-etanol-etylacetat (WEEa) och etanol-metyletylketon- toluen(EMekT). För den fasta fasen användes fysikaliska egenskaper liknande Pyrex. Sammansättnings- och temperatur-profiler visade att det inte finns något motstånd mot värmeöverföring i den fasta fasen och att värmeöverföringen sker mycket snabbare än materieöverförningen. Selektivitetsdiagram ritades. Resultaten indikerar att selektivititen är en viktig parmeter för att förutsäga beteendet vid torkning. Retentionsförhållandet användes som ett prestandamått. Dess variation med avseende på förändringar av driftsparmetrar, bland annat gasen hastighet och temperatur samt den fasta fasens temperatur och partikelstorlek, studerades. En modifiering av modellen undersöktes genom att införa en vätskehalts-beroende faktor för diffusionsmotståndet. Detta minskade värdena på retentionsförhållandena. Vibrationens inverkan på värme- och materieöverföring infördes genom att använda Sbrodov samband, och den resulterande effekten på retentionsförhållandet observerades.
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Noman, Rashed. "High velocity gas flow in porous media : effects of pore structure and liquid saturation." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47205.
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Lapkin, Alexei A. "Porous membrane phase contactor for gas-liquid homogeneous catalytic reactions : direct hydration of propene." Thesis, University of Bath, 2000. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760743.
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Courtney, Daniel George. "Ionic liquid ion source emitter arrays fabricated on bulk porous substrates for spacecraft propulsion." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67173.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 305-321).
Ionic Liquid Ion Sources (ILIS) are a subset of electrospray capable of producing bipolar beams of pure ions from ionic liquids. Ionic liquids are room temperature molten salts, characterized by negligible vapor pressures, relative high conductivities and surface tensions lower than water. Compared with the colloid form of electrospray, renowned for its applications to spectroscopy, ILIS yield highly monoenergetic beams composed entirely of ions. In this respect they are similar to Liquid Metal Ions Sources, but offer the ability to emit both positive and negative ions from a benign propellant that remains in the liquid state over a wide range of temperatures. When applied to spacecraft propulsion these sources are very power efficient and yield high specific impulses. Furthermore. the low flow rates and negligible vapor pressures of ionic liquids allow for passive feeding systems which can remain exposed to the vacuum of space. This configuration would remove the need for pressurized propellant tanks or valves, both of which are difficult to miniaturize for small satellites. However; the thrust produced from each emitter is very low, less than 0.1 [mu]N. As a result, compact arrays of active ILIS have been sought since their discovery. If arrays of modest packing density (~ 5 emitters/mm²) could be achieved, ILIS as thrusters would offer a scalable form of propulsion capable of providing useful thrust levels to small satellites with performance comparable to established, but difficult to miniaturize, plasma based ion engines. This research has sought a technique for creating arrays of ILIS from bulk porous substrates as part of an overall process for microfabricating complete thrusters. The thesis includes a survey of potential fabrication methods considering both suitability for forming arrays of ILIS and the ability to integrate each technique within a thruster packaging process. Electrochemical etching is highly selective and can proceed at rates which are limited by mass transport conditions. In this thesis we show how this etching regime can be exploited to smoothly remove material from the surface of a bulk porous metal substrate without damaging the internal pore structure. Dry film photoresists have been identified as a suitable alternative to spin on techniques for porous materials and have been applied within an electrochemical etching process. A two step process for forming arrays of ILIS has been motivated using numerical simulations of the etching process to predict emitter profiles and investigate the impacts of non-uniform etching conditions. These concepts have been applied experimentally using a custom built, automated, etching station capable of repeatedly producing arrays of 480 emitters spaced 500 pm apart on a 1 x 1 cm porous nickel substrate pre-mounted, and aligned, within a silicon thruster package. The emitters are typically 165 [mu]m tall with rounded tips suitable for operation as ILIS. Pulsed voltage conditions were found to significantly enhance wafer level uniformity enabling fabrication of functional emitters within a few hundred [mu]m of the substrate boundary. The structures have been smoothed and rounded, making them suitable for use as ILIS, during a secondary etch process using electrolytes doped with nickel chloride to suppress transient effects. These doped solutions enabled a few [mu]m of material to be removed selectively from the porous surface while maintaining smooth features. These arrays have been mounted and aligned with electrostatic grids to demonstrate their emission capabilities. Propellant has been fed to the emitters by capillarity within the porous bulk and then extracted at potentials as low as 850 V. Beam currents exceeding several 100 [mu]A at both positive and negative polarities have been measured using both EMIIm and EMI-BF₄ ionic liquid propellant. Two complete devices were tested yielding large beam currents and very high transmission fractions (- 88-100 %) from both attempts. We estimate that these devices can supply 10's of [mu]N of thrust at modest operating potentials, ~ 1.5 kV. with a specific impulse of roughly 2000-3000 s. When completely packaged, the thrusters measure 1.2 x 1.2 x 0.2 cm, weigh less than 1 g and require less than 0.65 W of operating power. These characteristics would be ideal for a small satellites where volume, mass and power are all at a premium, while the thrust levels would be sufficient to enable a variety of orbit variation and attitude control maneuvers. For example, applied to a CubeSat, this type of thruster system, including PPU, would occupy roughly 10 % of the spacecraft volume and mass while enabling de-orbiting from an 800 km altitude in roughly 100 days, compared with many years when left to decay naturally.
by Daniel George Courtney.
Ph.D.
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Kordás, K. (Krisztián). "Laser-assisted chemical liquid-phase deposition of metals for micro- and optoelectronics." Doctoral thesis, University of Oulu, 2002. http://urn.fi/urn:isbn:9514266862.
Full textAbstract:
Abstract
The demands toward the development of simple and cost-effective fabrication methods of metallic structures with high lateral resolution on different substrates - applied in many fields of technology, such as in microelectronics, optoelectronics, micromechanics as well as in sensor and actuator applications - gave the idea to perform this research. Due to its simplicity, laser-assisted chemical liquid-phase deposition (LCLD) has been investigated and applied for the metallization of surfaces having practical importance (Si, GaAs, SiO2, Si3N4, etc.) since the beginning of the 80s. By the invention of novel substrates (polyimide, porous silicon), it was adequate to work out new precursors or just adopt old ones and optimise LCLD in order to fabricate metallic micro-patterns upon these materials for various purposes.
According to the motivations mentioned above, LCLD was utilized for the fabrication of palladium (Pd) micro-patterns on polyimide (PI), polyimide/copper flexible printed circuit boards (PCBs), fused silica (SiO2) and silicon (Si). The selective metallization of porous silicon (PS) has been carried out with nickel (Ni). Depending on the types of lasers, either the focusing (Ar+ laser beam) or diaphragm projection (KrF and XeCl excimer laser pulses) method was employed. In the course of the work, various precursors of the corresponding metals have been investigated and utilized.
In the beginning, the pyrolytic decomposition of palladium-amine complex ions ([Pd(NH3)4]2+) on PI by a scanned and focused Ar+ laser beam was optimised and discussed. Thick (up to several micrometers) and narrow (~ 10 μm) Pd conductor lines with electrical conductivity close to that of the bulk were obtained. In the continuation of these investigations, the precursor was developed further. [Pd(NH3)4]2+ was mixed with the solution of formaldehyde (HCOH) in order to induce the reduction of the metal complex ions. To our knowledge, we were the first - so far - who applied this solution and described the reaction. With the proper choice of the laser parameters, thin Pd films as catalyst layers for electroless copper plating were deposited utilizing Ar+ and excimer lasers as well. The chemically plated copper deposits - upon the obtained Pd film - have excellent electrical and good mechanical properties.
In the second part of the thesis, three practical applications (metallization of via holes drilled in PI/Cu flexible PCBs, end-mirror fabrication on single-mode optical fibers, and carbon nanotube growth on Pd activated Si and Si/SiO2 substrates) of Pd LCLD were realized. The previously presented [Pd(NH3)4]2+ and [Pd(NH3)4]2+/HCOH precursors were employed for creating the catalyst Pd layers for the carbon nanotube chemical vapor-phase deposition and for the autocatalytic electroless chemical copper plating, respectively.
Finally, a simple novel method was introduced for the area-selective metallization of PS. Since the surface of PS reduces spontaneously most metals from their aqueous solutions, it is difficult to realize localized metal deposition from liquid-phase precursors on it. We proposed the application of a stable Ni plating bath from which the metal deposits only when the PS is irradiated with photons having wavelength shorter than 689 nm, thus making possible an area-selective laser-assisted metal deposition.
The deposited metal structures and patterns were analysed by field emission scanning electron microscopy (FESEM) equipped with energy dispersive spectrometer (EDS), by the milling and imaging modes of a focused ion beam system (FIB), optical microscopy, profilometry, resistance, and by reflectance measurements.