Dissertations / Theses on the topic 'Interfacial Transport'
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Lu, Zhengmao. "Evaporation from nanopores : probing interfacial transport." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/118723.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 82-87).
Evaporation, a commonly found phenomenon in nature, is widely used in thermal management, water purification, and steam generation as it takes advantage of the enthalpy of vaporization. Despite being extensively studied for decades, the fundamental understanding of evaporation, which is necessary for making full use of evaporation, remains limited up to date. It is in general difficult to experimentally characterize the interfacial heat and mass transfer during evaporation. In this thesis, we designed and microfabricated an ultrathin nanoporous membrane as an experimental platform to overcome some critical challenges including: (1) realizing accurate and yet non-invasive interface temperature measurement; (2) decoupling the interfacial transport resistance from the thermofluidic resistance in the liquid phase and the diffusion resistance in the vapor phase; and (3) mitigating the blockage risk of the liquid-vapor interface due to nonevaporative contaminants. Our nano device consisted of an ultrathin free-standing membrane (~200 nm thick) containing an array of nanopores (pore diameter ~100 nm). A gold layer deposited on the membrane served as an electric heater to induce evaporation as well as a resistive temperature detector to closely monitor the interface temperature. This configuration minimizes the thermofluidic resistance in the liquid and mitigates the contamination risk. We characterized evaporation from this nano device in air as well as pure vapor. We demonstrated interfacial heat fluxes of ~~500 W/cm² for evaporation in air, where we elucidated that the Maxwell- Stefan equation governed the overall transport instead of Fick's law, especially in the high flux regime. In vapor, we achieved kinetically limited evaporation with an interfacial heat transfer coefficient up to 54 kW/cm² K. We utilized the kinetic theory with the Boltzmann transport equation to model the evaporative transport. With both experiments and modeling, we demonstrated that the kinetic limit of evaporation is determined by the pressure ratio between the vapor in the far field and that generated by the interface. The improved fundamental understanding of evaporation that we gained indicates the significant promise of utilizing an ultrathin nanoporous design to achieve high heat fluxes for evaporation in thermal management, desalination, steam generation, and beyond.
by Zhengmao Lu.
Ph. D.
Levitz, Pierre, Patrick Bonnaud, Pierre-Andre Cazade, Roland J. M. Pellenq, and Benoit Coasne. "Molecular intermittent dynamics in interfacial confinement." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-184681.
Full textLevitz, Pierre, Patrick Bonnaud, Pierre-Andre Cazade, Roland J. M. Pellenq, and Benoit Coasne. "Molecular intermittent dynamics in interfacial confinement." Diffusion fundamentals 16 (2011) 16, S. 1-2, 2011. https://ul.qucosa.de/id/qucosa%3A13745.
Full textFang, Chao. "Pore-scale Interfacial and Transport Phenomena in Hydrocarbon Reservoirs." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/89911.
Full textDoctor of Philosophy
Meeting the ever-increasing energy demand requires efficient extraction of hydrocarbons from unconventional reservoirs and enhanced recovery from conventional reservoirs, which necessitate a thorough understanding of the interfacial and transport phenomena involved in the extraction process. Abundant water is found in both conventional oil reservoirs and emerging hydrocarbon reservoirs such as shales. The interfacial behavior and transport of water and hydrocarbon in these systems can largely affect the oil and gas recovery process, but are not well understood, especially at pore scale. To fill in the knowledge gap on these important problems, this dissertation focuses on the pore-scale multiphase interfacial and transport phenomena in hydrocarbon reservoirs. In shales, water is found to imbibe into strongly hydrophilic nanopores even though the pore is filled with highly pressurized methane. Methane gas can invade into water-filled nanopores if its pressure exceeds a threshold value, and the thin residual water films on the pore walls significantly affect the threshold pressure. Oil droplet can invade pores narrower than their diameter, and the energy cost for their invasion can only be computed accurately if the surface forces in the thin film formed between the droplet and pore surface are considered. In conventional reservoirs, thin brine films between oil droplet and rock greatly affect the wettability of oil droplets on the rock surface and thus the effectiveness of low-salinity waterflooding. In brine films with sub-nanometer thickness, the ion distribution differs from that near isolated rock surfaces but the structure of water-brine/rock interfaces is similar to their unconfined counterparts. The disjoining pressure in thin brine films and its response to the salinity change follow the trend predicted by classical theories, but new features are also found. A notable slip between the brine film and the oil phase can occur, which can facilitate the recovery of oil from reservoirs.
Wang, Xia. "Simulations of Two-phase Flows Using Interfacial Area Transport Equation." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1282066341.
Full textLiu, Ying. "Nanoscale Thermal Transport at Graphene-Soft Material Interfaces." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/71715.
Full textPh. D.
Greco, Pierpaolo <1977>. "Microfluidic device and interfacial transport: application to biomolecules and nanostructures." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1663/.
Full textSharma, Prabhakar. "Effect of centrifugal and interfacial forces on colloid transport and mobilization." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Dissertations/Fall2007/P_Sharma_112907.pdf.
Full textManzanares-Papayanopoulos, Emilio. "Bulk and interfacial molecular structure near liquid-liquid critical points." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327623.
Full textAtay, N. Z. "Transport and interfacial exchange kinetics in one- and two-phase disperse systems." Thesis, University of Kent, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374831.
Full textKyndiah, Adrica <1987>. "Interfacial interactions, charge transport and growth phenomena in Organic Field Effect Transistors." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7100/.
Full textLiu, Hua. "Investigation on Transport Mechanisms and Interfacial Properties of Solar Cells By Simulation." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1365873270.
Full textInyang, Oto-Obong Andrew. "Magnetic proximity effect and interfacial spin dependent transport in ferromagnet/heavy metal thin films." Thesis, Durham University, 2018. http://etheses.dur.ac.uk/12795/.
Full textBradley, Colin. "Understanding Charge Transport and Selectivitiy in Ionically Functionalized Fullerenes for Electron-Selective Interfacial Layers." Thesis, University of Oregon, 2018. http://hdl.handle.net/1794/23171.
Full text10000-01-01
Bahukudumbi, Pradipkumar. "Energy landscape and electric field mediated interfacial colloidal assembly." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5883.
Full textGonçalves, Bruno Batista. "Detalhando a solução unidimensional do método OQA com função coeficiente de redução constante aplicado ao transporte escalar interfacial turbulento." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-01092014-091040/.
Full textThe adequate quantification of interfacial scalar transport in turbulent flows is of practical interest for industrial processes and in environmental problems. The phenomenon is mathematically complex due to the use of unclosed nonlinear statistical equations. In this study, we analyze details of the method of Random Square Waves (RSW), which provides a statistical quantification that allows closing the set of equations and getting the normalized scalar profile of the one-dimensional turbulent scalar variable, which, in an idealized case, depends on only two nondimensional parameters, k and A (in this case, k represents a transfer coefficient and A depends on the interaction between the molecular and turbulent transports). Numerical simulations were performed in order to verify the influence of the higher order of derivatives over the normalized concentration function. The sensitivity of the model to the relevant parameters and the analysis of its intrinsic parameters were also performed. An important aspect is the analysis of the boundary conditions, for which an additional condition was proposed and employed in the bulk liquid (with based on physical grounds). Because the initial studies have focused on examples of mass transfer, an extension to the case of heat transport was here considered. The results reproduce the behavior of experimental data reported in the literature.
Maya, Visuet Enrique. "Electrolyte Transport And Interfacial Initiation Mechanisms Of Zinc Rich Epoxy Nanocoating/Substrate System Under Corrosive Environment." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1430762942.
Full textRipollés, Sanchis Teresa. "Interfacial and Bulk Operation of Polymeric Solar Cells by Optoelectronics and Structural Techniques." Doctoral thesis, Universitat Jaume I, 2014. http://hdl.handle.net/10803/277095.
Full textCristian, Alina. "Systèmes moléculaires et matériaux structurés pour la conduction ionique et le transport d’eau." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS114/document.
Full textThe aim of this work is the study of ion and water transport either across bilayer membranes or polymeric membranes used for reverse osmosis. In the first part, this transport through self-assembled synthetic systems was studied; the transport selectivity is in strong relation with the supramolecular structure, formed by weak intra and intermolecular bonds. Ion transport is studied by fluorescence spectroscopy and water transport is studied by light scattering using “stopped flow” technique. The objective is to obtain systems that could imitate transport functions of biomolecules as transmembrane proteins. This functional mimicry is achieved through self-assembly of organic molecules containing imidazole cycle and urea function that can self-assembly and form selective pathways for ion transport. To create the equivalent of the cell membrane, we used unilamellar lipid vesicles. Then, we determined a structure - transport activity relationship for a series of synthesized compounds. For the second part of this work we described the fabrication and the characterization of new thin film composite membranes for water desalination that can present a good balance between permeability and salt rejection. A series of hydrazides as molecular precursors was synthesized in order to replace the metaphenylene diamine (MPD), classically used. Again, hydrogen bonds play an important role, because the rejection is due to a high cross-linking. The polymers synthesized by interfacial polymerization were characterized by infrared spectroscopy, thermogravimetric analysis, and X-Ray diffraction. The membrane films were characterized by scanning electron microscopy, atomic force microscopy and contact angle measurements. Membrane performances were then tested in cross-flow filtration of water and saline solutions
Rouhnia, Mohamad. "Vertical Transport of Sediment from Muddy Buoyant River Plumes in the Presence of Different Modes of Interfacial Instabilities." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/82506.
Full textPh. D.
Gao, Xiao. "Elucidation of Ionomer/Electrode Interfacial Phenomena in Polymer Electrolyte Fuel Cells." Kyoto University, 2020. http://hdl.handle.net/2433/254528.
Full text0048
新制・課程博士
博士(人間・環境学)
甲第22708号
人博第958号
新制||人||227(附属図書館)
2020||人博||958(吉田南総合図書館)
京都大学大学院人間・環境学研究科相関環境学専攻
(主査)教授 内本 喜晴, 教授 高木 紀明, 教授 中村 敏浩
学位規則第4条第1項該当
Crozier, Paul S. "Slab-geometry molecular dynamics simulations : development and application to calculation of activity coefficients, interfacial electrochemistry, and ion channel transport /." Diss., CLICK HERE for online access:, 2001. http://contentdm.lib.byu.edu/ETD/image/etd15.pdf.
Full textCrozier, Paul S. "Slab-Geometry Molecular Dynamics Simulations: Development and Application to Calculation of Activity Coefficients, Interfacial Electrochemistry, and Ion Channel Transport." BYU ScholarsArchive, 2002. https://scholarsarchive.byu.edu/etd/2.
Full textAL-AZMI, BADER SHABEEB. "ANALYSIS OF TRANSPORT MODELS AND COMPUTATION ALGORITHMS FOR FLOW THROUGH POROUS MEDIA." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1051059625.
Full textMBANGANGOYE, BERNARD. "Modelisation des ecoulements multiphasiques dans les lignes de transport petrolier - contribution a l'etude du frottement interfacial en regime stratifie liquide-gaz." Paris, ENSAM, 2001. http://www.theses.fr/2001ENAM0003.
Full textDelvert, Alexandre. "Étude de la formation, du transport et de la destruction par vidange de bulles interfaciales." Thesis, Rennes 1, 2020. https://ged.univ-rennes1.fr/nuxeo/site/esupversions/62340f16-03da-4a74-a405-afba30b16427.
Full textBubbles are everyday-life fluid objects that amused us when we were children. Also, they are a source of the inspiration for artists and an important educational tool to introduce several notions of physics. Not surprisingly, these objects are at the origin of many scientific studies for centuries. In this manuscript, we are interested in the formation, travel and destruction of interfacial bubbles, i.e., bubbles in contact with a solid or an air-liquid interface. First, we present an experiment about the formation of interfacial bubbles by the impact, at constant velocity, of liquid films on the free surface of a liquid bath. The air trapped between the bath and the liquid film drives the formation of an interfacial bubble and its size increases with the impact velocity. We show the existence of two distinct regimes of the air flow : one of them is governed by a visco-capillary mechanism at low impact velocity, the other, at high impact velocity, is driven by a competition between inertia and capillarity. Thereafter, we present a study about shrinking surface soap bubbles. We revisit the classical problem of the draining of a tank studying the case of a deformable tank, i.e. , an interfacial bubble sitting on a plate drilled with a circular orifice. Shrinking is studied as functions of key setting geometric and physicochemical parameters of the problem. We show the shrinking time can be understood with a model for the air flow based on Bernoulli’s principle, and a motion of a bubble during the shrinking that is driven by capillarity and is limited by the friction acting on its foot. We develop in the last chapter an educative method to measure the air viscosity with simple experimental equipment regularly used in our everyday life : a smartphone, a funnel, a pipe and soap solution. The experiment consists of studying the spontaneous motion of a thin liquid film in a funnel. We show this experiment can be used as a viscosimeter for gases (air in our experiments) with the conditions make the air flow describable by the Poiseuille’s equation and the liquid film moves quasi-statically
Doup, Benjamin. "Methodology Development of a Gas-Liquid Dynamic Flow Regime Transition Model." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1409031809.
Full textAkbar, Muhammad Khalid. "Transport Phenomena in Complex Two and Three-Phase Flow Systems." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4897.
Full textPellacani, Filippo [Verfasser], Rafael [Akademischer Betreuer] Macián-Juan, and Vicent Sergio [Akademischer Betreuer] Chiva. "Development and Validation of Bubble Breakup and Coalescence Constitutive Models for the One-Group Interfacial Area Transport Equation / Filippo Pellacani. Gutachter: Sergio Chiva Vicent ; Rafael Macián-Juan. Betreuer: Rafael Macián-Juan." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/104199480X/34.
Full textCroeser, Sophia Louw. "Interfacing Marabastad." Diss., Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-05182005-112742.
Full textKuidjo, Kuidjo Emmanuel Vianney. "Towards a predictive model to reproduce flow regime transitions in gas-liquid flows with Neptune CFD : from a dispersed to a separated regime." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0456.
Full textIn nuclear reactors, several regimes of gas-liquid flows may occur with some transitions between them. The main challenges associated with simulating these transitions in 3D CFD codes are associated with deformable interfaces of different sizes, accounting for coalescence and breakup interactions between gas structures and developing flow regime independent closure relations. This work aims at modelling and simulating the hydrodynamics of adiabatic gas-liquid flows thanks to a three-field two-fluid model in Neptune CFD. In a first step, a model with one continuous liquid field and two dispersed gas fields for small and large bubbles is used to simulate cap and churn flows with a void fraction up to 0.5 and a focus is put on the interfacial area prediction. In a second step, the second dispersed field is replaced by a hybrid continuous/dispersed field representing both large bubbles and continuous gas regions. The model is validated on several flow regimes in large diameter pipes and in confined rectangular channels
Alali, Abdullah [Verfasser], Rafael [Akademischer Betreuer] Macián-Juan, and Vicent Sergio [Akademischer Betreuer] Chiva. "Development and validation of new solver based on the interfacial area transport equation for the numerical simulation of sub-cooled boiling with OpenFOAM CFD code for nuclear safety applications / Abdullah Alali. Gutachter: Sergio Chiva Vicent ; Rafael Macián-Juan. Betreuer: Rafael Macián-Juan." München : Universitätsbibliothek der TU München, 2014. http://d-nb.info/1048677257/34.
Full textPenny, Melissa. "Mathematical modelling of dye-sensitised solar cells." Queensland University of Technology, 2006. http://eprints.qut.edu.au/16270/.
Full textRichardson, Jerry Christopher. "Transport, vaporization, and ionization in particle beam liquid chromatography/mass spectrometry interfacing." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/30974.
Full textKarcher, Viviane. "Determinação da energia interfacial de emulsões de agua em oleo pesado." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265665.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica e Instituto de Geociencias
Made available in DSpace on 2018-08-12T08:12:48Z (GMT). No. of bitstreams: 1 Karcher_Viviane_M.pdf: 1731022 bytes, checksum: 355de3e34591ff15d14ab367330328f8 (MD5) Previous issue date: 2008
Resumo: Durante a produção de petróleo, é comum o aparecimento de água sob a forma de gotas finamente dispersas no óleo. A água pode ser oriunda de métodos de recuperação avançada e/ou do próprio reservatório (água conata). O cisalhamento turbulento produzido durante o escoamento destes fluidos através de dutos ou dispositivos, como bombas, ou até mesmo no reservatório, pode causar a formação de emulsões de água em óleo (A/O). Para os óleos pesados,estas emulsões permanecem estáveis por um período longo devido à presença de agentes emulsificantes naturais no petróleo cru. Por essa razão, a separação dessas emulsões necessita de equipamentos específicos, o que contribui para o aumento do custo do processo. O objetivo deste estudo é investigar as propriedades interfaciais de emulsões A/O compostas por água e petróleo pesado brasileiro. Para tanto, um aparato experimental foi construído com o objetivo de calcular a energia interfacial dessas emulsões. As emulsões A/O foram geradas através de um aparelho homogeneizador rotativo imerso em um vaso calorimétrico. Dois métodos foram empregados: o método calorimétrico, baseado no balanço de energia da emulsificação, e o método padrão, baseado na medida do tamanho e distribuição das gotas através da técnica de microscopia óptica. As incertezas nas medidas experimentais, em ambos os métodos, foram estudadas a fim de avaliar a viabilidade de cada um. Como principais resultados deste estudo, as magnitudes relativas dos termos do balanço de energia durante a emulsificação foram obtidas. O comportamento reológico destas emulsões também foi estudado.
Abstract: In petroleum production operations, water is commonly present within the oil phase as a finely dispersed phase. This situation originates from enhanced oil recovery methods and/or the presence of connate water inside the own reservoir. The turbulent shear associated with fluid flow during of heavy crude transportation through pipelines may cause the formation of water-in-oil emulsions (W/O). These remain stable for a long time, due the presence of naturally emulsifying agents in the crude oil phase. Therefore, emulsion separation requires specific equipments which contribute to increase the processes costs. The main purpose of this study is to investigate the interfacial properties of W/O emulsions composed by water and a Brazilian heavy crude oil. For that purpose an experimental set-up was built in order to measure the interfacial energy of the emulsions. The W/O emulsions were prepared in a calorimeter vessel by using a rotating impeller. Two methods were used, namely, the calorimetric method based on the energy balance for the emulsification and the standard method of the droplet size and distribution by means of a digital microscope. The uncertainty in experimental measurements was determined for both methods, in order to evaluate their feasibility. The main result of this research is the determination of the relative magnitudes of the different terms in the energy balance during emulsification. Results for the rheological behavior of W/O emulsions are also reported.
Mestrado
Explotação
Mestre em Ciências e Engenharia de Petróleo
Castro, Pollyana Souza. "Desenvolvimento de microssensores eletroquímicos e aplicações no estudo de processos dinâmicos interfaciais utilizando microscopia eletroquímica de varredura." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-06042016-145742/.
Full textThe study reported in this thesis shows in details the fabrication and characterization of different electrochemical microsensors which have been employed as probes in SEPM. Thus, the characterization of surfaces can be performed by exploiting different interfacial phenomena that are relevant to life sciences. In this sense, the interfaces of crystalline materials such as hydroxyapatite (dental materials) and calcite were the focus of this study. Thus, different SEPM techniques were explored in order to obtain relevant information related to dental materials processes such as acid erosion and hypersensitivity. Initially, platinum microelectrodes were developed employing conventional methodology that utilizes microfibers encapsulated in glass capillaries. Amperometric SECM mode was used to obtain information regarding the topography changes of tooth enamel caused by contact with acid chemicals. In addition, SECM was used to study the transport of electroactive species in dentin samples. Investigations related to the treatment of dental hypersensitivity and dental whitening were also evaluated. SECM results were compared with SEM images obtained under the same experimental conditions. Ion-selective microelectrode (ISME) based on the ionophore membrane sensitive to calcium ions were also developed and characterized followed by application in SECM potentiometric mode. The acid dissolution of bovine enamel (dental erosion) was investigated at different pH values (2.5; 4.5; 6.8). In addition, the transport of calcium ions through synthetic porous membranes was evaluated at a tip/substrate distance of 300µm. Changes in calcium ion flux were studied in the presence and absence of magnetic fields generated by magnetite nanoparticles incorporated into the porous membrane. Calcite microcrystals easily synthesized by precipitation method were used as a model of an interfacial surface for investigations which can be correlated to the dental materials. Thus, glass nanopipette filled with supporting electrolyte was fabricated and used as SICM probe. The high resolution topographic mapping of the calcite microcrystal was obtained using hopping mode. Additionally, ISME-SICM multifunction probes were developed and characterized for simultaneous investigations related to the topographical changes and quantification of local calcium ions on the surface of a calcite microcrystal. The addition of acidic reagents in the SICM channel promoted the dissolution of the microcrystal surface and dissolution kinetic data were obtained. Investigations in neutral medium were also studied using the ISME-SICM multifunctional probe. The experimental results were also compared with those obtained by computer simulation.
Penny, Melissa. "Mathematical modelling of dye-sensitised solar cells." Thesis, Queensland University of Technology, 2006. https://eprints.qut.edu.au/16270/1/Melissa_Penny_Thesis.pdf.
Full textSeo, Youngmi. "Structure and Dynamic Properties of Interfacially Modified Block Copolymers from Molecular Dynamics Simulations." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492628195548591.
Full textJha, Neha [Verfasser], Peter [Akademischer Betreuer] Oppeneer, Markus [Gutachter] Münzenberg, and Peter [Gutachter] Oppeneer. "Interfacially Tuned Spin Transport Towards Molecular Spintronics / Neha Jha ; Gutachter: Markus Münzenberg, Peter Oppeneer ; Betreuer: Peter Oppeneer." Greifswald : Universität Greifswald, 2021. http://d-nb.info/1237413400/34.
Full textWhite, Joey. "USING DATAFLOW ARCHITECTURE TO SOLVE THE TRANSPORT LAG PROBLEM WHEN INTERFACING WITH AN ENGINEERING MODEL FLIGHT COMPUTER IN A TELEMETRY SIMULATION." International Foundation for Telemetering, 1991. http://hdl.handle.net/10150/613183.
Full textOne of the most challenging technical problems in the development of a spacecraft telemetry simulation is the interface with a flight computer running real-world flight software. The ability of the simulation to satisfy flight software requests for telemetry data, and to load, mode, and control the flight software along with the simulation, can be constrained or degraded using conventional interface solutions. Telemetry dataflow architecture systems can be utilized to solve the interface problems with less constraints. This is an especially attractive solution in a telemetry simulation where the telemetry system can also be used to format and serialize spacecraft telemetry, and receive and preprocess commands. This paper discusses the concepts developed for such a system for a training simulation of the Orbital Maneuvering Vehicle for NASA at Johnson Space Center.
Ahmad, Ahmad. "Caractérisation globale et locale de l'écoulement à surface libre et en charge de systèmes liquide-liquide : application au procédé d’injection pariétale pour le transport des pétroles bruts." Brest, 2010. http://www.theses.fr/2010BRES2013.
Full textThe present dissertation reports on investigations on open-channel flows and Poiseuille flows of liquid/liquid systems. The first part of the dissertation considers the propagation of a gravity current over a denser ambient miscible liquid. A controlled flow rate of fresh water and of polymer solutions were released upon the free surface of an ambient salty water at rest in a basin, in order to characterize with te help of a method based on image analysis and the exploitation of spatio-temporal diagrams, the effect of polymer shear-thinning property on the temporal evolution of front progress and spreading of gravity current in ambient liquid and of mixing layer depth as well. A local study consisting in the development of a large scale PIV, aiming at describe to hydrodynamic fields existing in both fluids completed the previous global study. The second part of the dissertation considers a co-current water/oil flow in a duct, in order to simulate the lubricated pipelining of heavy crude oils which were being represented by oils gifted with high viscosity and a viscoplastic rheological behaviour. The effect of bed slope and flow rates ratio on global pressure drop were characterized in order to define the conditions of process optimal efficiency. A local characterization of the interfacial instabilities completed the previous global investigation
Morel, Floriane. "Compréhension des phénomènes interfaciaux dans les composites à base de charges carbonate de calcium précipité : influence du traitement de surface et du procédé de mise en œuvre." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00733711.
Full textBai, Guiyu. "Interfacial transport driven by redox active surfactants." 2005. http://catalog.hathitrust.org/api/volumes/oclc/64280381.html.
Full text"Microscale transport phenomena and interfacial reactions in diverse applications." Tulane University, 2021.
Find full textInterfacial phenomena and reactions commonly occur in our daily life. A wide range of applications from industrial products to medical technology involve interfacial phenomena such as water-repellent fabrics, non-stick Teflon and motor oils. Motor oils contain different additives such as overbased detergents and dispersants. These additives are well suspended in oil phase by surfactants. Various reactions take place between these additives and contaminant particles, and different behaviors of particle dispersion also play an important role on affecting the reactions. To obtain deep understanding of the phenomena, a cost effective and time saving method is developed to study the behavior of microscale transport phenomena and interfacial reactions kinetics. The first part of the thesis investigates designing and developing a microdevice, heating capillary video microscopy system. The technique provides direct visual observation and quantification, and can be operated at high temperatures. The developing process involves fabrication and characterization of transparent and conductive ITO (Indium Tin Oxide) thin film. Sol-gel dip coating process was used to coat the thin film. Factors that affect film performance was discussed. Immersing time and heat treatment temperature had significant effects on film conductivity. The optimal coating conditions was determined with immersing time 30 seconds, heat treatment temperature 500℃, coating times: 3 , and dipping rate 7 cm/min. The second part of the work is one of the applications with the low-cost method, “Time-dependence of Asphaltene Dispersion by MCL Surfactants”. With combining grayscale image analysis, HFO (Heavy Fuel Oil) dispersion kinetics is quantified and discussed. Effects on HFO dispersion included those of surfactants’ type, over-basing level and temperature, while also discussing what Carbon chain lengths can be expected to perform better. For same-chain-length surfactants, samples with higher concentration of base showed lower ability of dispersing HFO. The third part of the thesis is to study Ethanol’s Effects on Acid Neutralization by Motor Oils. Sulfuric-acid neutralization kinetics by motor oils in the presence of ethanol was investigated for the first time in literatures by quantitatively visualizing the fate of acid drops in commercial motor oils via capillary video-microscopy. A very different behavior was exhibited at 100 ℃, with rate of acid neutralization being much faster in the presence of ethanol than in absence. With 1% ethanol and temperature of 100 ℃, acid droplets were neutralized in 2 minutes, whereas at room temperature droplets expanded ~35% in diameter after 60 minutes with little neutralization. This phenomenon is a valuable information for discussing the impact of ethanol blended gasoline on engines and for further, especially for low temperature environments. The last part is to study temperature and salting out effects on nicotine. Nicotine dissolution rates and diffusion coefficients in different NaCl concentration solutions are quantified and calculated with Epstein- Plesset Model. The results will be used for future research to design a continuous separation process to reach environmentally and economical goal.
1
Chia-yu Chen
Lin, Chu Loong, and 林志隆. "qelected Problems on Interfacial Transport Phenomena in Two- phase Systems." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/37038924283335861438.
Full text國立成功大學
航空太空工程學系
84
The present study constitutes an integral part of fundamentaland applied research on the mechanics and combustion of two-phase flow systems, in particular liquid-bubble anddroplet-gas flow in modern spray combustion and relatedtechnological applications. The study focuses attentionon the theoretical and numerical analysis of three selected topics, including transient group combustion of premixed clusters, the dynamic and thermochemical response of an air bubble under a sudden compression of the surrounding liquid fuel and finally, the spray combustion analysisand optimal design of the combustion efficiency of hybrid rockets
Chang, Yu-Cheng, and 張羽成. "Interfacial Charge Transport Kinetics in Dye-Sensitized and Perovskite Solar Cell." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/nzaekk.
Full text國立交通大學
應用化學系碩博士班
102
This study has investigated the electron transfer behaviour of dye sensitized solar cells (DSSC) and perovskite solar cell (PSC) using a range of time-resolved and steady state techniques. The enhanced understanding of these processes was then utilized to develop unique strategies to circumvent performance limitations associated with injection or recombination, thereby improving the power conversion efficiencies of the devices. In this study, four characterization techniques have been reported, transient photocurrent and photovoltage decay measurements, charge extraction measurement, photoinduced absorption spectroscopy and transient absorption spectroscopy. This thesis provide an account of each technique about its operating principle, experimental setup and data analysis. The transient photoelectric measurements, are obtained under short-circuit and open-circuit conditions, respectively, and the electron diffusion coefficients and electron lifetimes are extracted from fitting the decay curves accordingly. For the photoinduced absorption spectroscopy, which is useful in the characterization of long-lived (> μs) non-radiative excited states and used as the first step for transient absorption measurement. As case studies for each technique, examples are given to rationalize the observed potential shift, decay coefficients of electron transport and of charge recombination in relation to the corresponding photovoltaic performance of the device. For porphyrin dyes and organic dyes, by using the transient photoelectric measurements to understand the charge recombination process and TiO2 potential shift; for TiO2 nanostructure, we measured the charge transport kinetics with different morphology TiO2. For perovskite solar cell, we used these techniques to study the charge transport kinetics of the devices.
Li, Xueliang. "Transport phenomena in foam fractionation." Thesis, 2012. http://hdl.handle.net/1959.13/932169.
Full textThis dissertation consists of experimental and theoretical approaches towards a better understanding of some principal aspects of the foam fractionation process: (i) interfacial adsorption, (ii) foam stability, (iii) foam hydrodynamics and (iv) process intensification and device design. Studies on interfacial adsorption include a flexible and robust numerical solution to the Ward-Tordai equation that can be used with any adsorption isotherm. The scheme makes use of the trapezium rule of numerical integration, coupled with the bisection method of root-finding to guarantee local consistency. The scheme is found to be robust and efficient. However, it is made clear that Ward-Tordai equation is only applicable for the adsorption of non-ionic surfactants onto quiescent planar or convex interfaces. For the adsorption of ionic surfactants onto the surface of a rising bubble in a foam fractionation column, experiments are carried out to study the rate and extent of adsorption. It is found that adsorption equilibrium of SDS (sodium dodecyl sulphate) in both the liquid pool and the foam layer can be achieved within 0.2 m of column depth. However, the equilibrium surface excess on a rising bubble is lower than that on a quiescent interface. Studies of foam stability include direct observation of inter-bubble gas diffusion in foams with different liquid fractions and the effect of environmental humidity on foam stability. Inter-bubble gas diffusion is found to be slow and only becomes significant in long term foam stability tests. However, inter-bubble gas diffusion itself does not lead to the collapse of a foam layer. Instead, it is shown conclusively that the bursting of bubbles at the free surface of a foam and the collapse of a foam layer are affected by the humidity gradient in the freeboard of a foam column. A mechanism based on the Marangoni instability is proposed to explain the dependency of foam stability on humidity. The mechanism is supported by experimental observations of the bursting of an isolated bubble under conditions of non-uniform evaporation via high speed video recording. The behaviour of pneumatic foams flowing vertically through an expansion or a contraction is theoretically and experimentally studied. It is demonstrated that although a sudden contraction of flow area decreases the in situ liquid fraction, it does not affect the volumetric liquid over-flow rate. Conversely, a sudden expansion of flow area decreases both the liquid fraction and the volumetric liquid over-flow rate. Implications of this analysis for foam fractionation device design, optimisation and process intensification are discussed. Finally, based on the theoretical analysis, a mechanistic explanation is proposed for a process intensification device. The device consists of a plate with a tube (foam riser) mounted in the centre. The plate has the same diameter of the foam column whilst the tube is narrower. When a foam riser-plate assembly is inserted into a conventional foam column, the foam is forced through a contraction of flow area followed by an expansion. A significant reduction in liquid flux is observed, without diminishing the surface area. However, due to the adsorption isotherm of SDS, the enrichment enhancement measured in the experiments herein is modest. It is believed that if the device is applied to other systems such as proteins where the adsorption isotherm favours high enrichment, the enhancement of enrichment will be more significant. The device is not optimised for any specific system in the current study. Several major aspects of foam fractionation technology that have only been addressed separately by different researchers previously are investigated on a systematic basis here. It is hoped that the work has not only provided enhanced mechanistic understanding of the foam fractionation process, but that it will also promote industrial adoption of the technology.
Lin, Chun-Ta, and 林均達. "Miniemulsion/miniemulsion polymerization dealing with interfacial behavior, thermodynamics, transport phenomena, and polymerization." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/47130425225365904220.
Full text國立臺灣科技大學
化學工程系
103
The modified Kabal’nov equation developed by a thermodynamic approach dealing with a regular solution of monomer and conventional low molecular weight costabilizer as the two-component disperse phase adequately described the Ostwald ripening rate data in a wide range of the volume fraction of costabilizer for styrene miniemulsions stabilized by a homolog of n-alkane costabilizers (CnH2n+2; n=10, 12, 16, 18, 20, 24, 32) upon aging at 25 ℃. The results showed that the costabilizer with the shortest chain length (C10H22) is not hydrophobic enough to effectively retard the Ostwald ripening process. The effectiveness of n-alkanes as costabilizer in suppressing the Ostwald ripening process increases with increasing n-alkane molecular weight. Nevertheless, further increasing the n-alkane chain length from C24H50 to C32H66 does not lead to significant improvement in the effectiveness of n-alkane as costabilizer. Another mechanistic model that describes the Ostwald ripening behavior with a regular solution of monomer (styrene (ST) herein) and different polymeric costabilizers as the disperse phase of miniemulsion in such a colloidal system was developed. The validity of this model was verified by the Ostwald ripening rate data obtained from ST miniemulsions stabilized by living polystyrene costabilizer (PSlc) or polystyrene costabilizer (PSc) upon aging at 25 ℃. PSlc is more effective in retarding the Ostwald ripening process than PSc, though PSlc and PSc have comparable number-average molecular weights. The model can be also used to study the mutual interaction between monomer and polymeric costabilizer. Satisfactory modeling results achieved for ST miniemulsions using polymethyl methacrylate as the costabilizer (PMMAc) further verify the general validity of the present model. The values of heat of mixing and interaction parameter between ST and different polymeric costabilizers were also determined. We then investigated the effects of the molecular weight of PSc and PMMAc on the Ostwald ripening behavior at 25 ℃ of ST miniemulsions and the polymerization of these miniemulsions. The effectiveness of PSc and PMMAc in retarding the diffusional degradation of ST miniemulsions decreases with increasing the molecular weight of PSc or PMMAc. The Ostwald ripening rate data were used to determine the critical chain length of polymeric costabilizers to induce chain entanglements. The resultant critical chain length to induce chain entanglements is 363871475 and 7668521 g mol-1 for PSc and PMMAc, respectively, which are comparable to those reported in the literature. The polymerization of the ST miniemulsions stabilized by PMMAc with different molecular weights at 70 ℃ were then carried out. The polymerization rate decreases with increasing the polymeric costabilizer molecular weight. This was attributed to the reduced number of latex particles (i.e., reaction loci) with the polymeric costabilizer molecular weight. The miniemulsion polymerization kinetics is primarily controlled by the particle nucleation process (the competition between the monomer droplet nucleation and homogeneous nucleation), which is closely related to the effectiveness of these costabilizers in retarding the Ostwald ripening process. Finally, RAFT miniemulsion polymerizations of styrene with living polystyrene (PSlc) serving as both RAFT reagent and polymer costabilizer were discussed. The miniemulsion upon aging at 25 oC showed satisfactory stability against the Ostwald Ripening process. The rate of polymerization for RAFT miniemulsion polymerization initiated by oil-soluble AIBN is much slower than that for the water-soluble SPS counterpart. In addition to the predominant monomer droplet nucleation, much stronger particle nucleation taking place in the continuous aqueous phase (homogeneous nucleation) for the run with AIBN was observed. It is the different extents of homogeneous nucleation that is responsible for the quite different kinetic behaviors between the RAFT miniemulsion polymerizations initiated by different types of initiator (AIBN versus SPS). Furthermore, increasing initial molar ratio of RAFT reagent to AIBN greatly enhances the characteristics of RAFT polymerization (i.e., better control over polymer chain growth with the progress of polymerization).
Hahn, Thomas. "Interfacial electrokinetic transport phenomena and their impact on DNA electrophoresis in microfluidics." Phd thesis, 2011. http://tuprints.ulb.tu-darmstadt.de/2433/1/PhDthesis_Hahn.pdf.
Full textReeser, Dorea Irma. "Effects of Aqueous Organic Coatings on the Interfacial Transport of Atmospheric Species." Thesis, 2013. http://hdl.handle.net/1807/43714.
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