Dissertations / Theses on the topic 'Liquid film model'

Liquid film flow is an important flow type in many applications of process engineering. For supporting experiments, theoretical and numerical investigations are required. The present state of the art is to model the liquid film flow with Navier--Stokes-based methods, whereas the lattice Boltzmann method is employed here. The final model has been developed within this treatise by means of a two-phase flow and a heat transfer model, and boundary and initial conditions. All these sub-models have been applied to simple test cases. It could be found that the two-phase model is capable of solving flow phenomena with a large density ratio which has been shown impressively in conjunction with wall boundary conditions. The heat transfer model was tested against spectral method results with a transient non-uniform flow field. It was possible to find optimal parameters for computation. The final model has been applied to steady-state film flow, and showed very good agreement to OpenFOAM simulations. Tests with transient film flow demonstrated that the model is also able to predict these flow phenomena
Flüssigkeitsfilmströmungen kommen in vielen verfahrenstechnischen Prozessen zum Einsatz. Zur Unterstützung von Experimenten sind theoretische und numerische Untersuchungen nötig. Stand der Technik ist es, Navier--Stokes-basierte Modelle zu verwenden, wohingegen hier die Lattice-Boltzmann-Methode verwendet wird. Das finale Modell wurde unter Verwendung eines Zweiphasen- und eines Wärmeübertragungsmodell entwickelt und geeignete Rand- und Anfangsbedingungen formuliert. Alle Untermodelle wurden anhand einfacher Testfälle überprüft. Es konnte herausgefunden werden, dass das Zweiphasenmodell Strömungen großer Dichteunterschiede rechnen kann, was eindrucksvoll im Zusammenhang mit Wandrandbedingungen gezeigt wurde. Das Wärmeübertragungsmodell wurde gegen eine Spektrallösung anhand eines transienten und nichtuniformen Strömungsproblemes getestet. Stationäre Filmströmungen zeigten sehr gute Übereinstimmungen mit OpenFOAM-Lösungen und instationäre Berechungen bewiesen, dass das Model auch solche Strömungen abbilden kann

Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Abdel-Khalik, Said; Committee Member: Ammar, Mostafa H.; Committee Member: Ghiaasiaan, S. Mostafa; Committee Member: Hertel, Nolan E.; Committee Member: Liu, Yingjie.

Le contact entre le jet d'eau et l'acier inoxydable fondu observe dans l'installation experimentale seizies provoque une pressurisation et une liberation de l'energie mecanique. On propose dans ce memoire une analyse et une interpretation de cette interaction a l'aide d'un modele thermodynamique et d'un modele parametrique. Les objectifs de ce travail sont: l'evaluation du terme source de l'interaction, a savoir l'energie reellement transmise dans l'interaction et celle transformee en travail mecanique et l'amelioration des connaissances sur l'interaction thermique metal fondu et notamment dans le cas d'une injection de l'eau sur le metal fondu. Les resultats importants sont: le travail mesure experimentalement est representatif du travail maximum liberable dans seizies, la masse d'acier participant a ete determine et certains mecanismes physiques ont ete valides

Model-H is used to describe structures found in the phase separation in films of binary liquid mixture that have a surface that is free to deform and also may energetically prefer one of the components. The film rests on a solid smooth substrate that has no preference for any component. On the one hand the study focuses on static aspects by investigating steady states that are characterised by their concentration and film height profiles. A large variety of such states are systematically analysed by numerically constructing bifurcation diagrams in dependence of a number of control parameters. The numerical method used is based on minimising the free energy functional at given constraints within a finite element method for a variable domain shape. The structure of the bifurcation diagrams is related to the symmetry properties of the individual solutions on the various branches. On the other hand the full time dependent model-H is linearised about selected steady states, in particular, the laterally invariant, i.e.\ layered states. The resulting dispersion relations are discussed and related to the corresponding bifurcation points of the steady states. In general, the results do well agree and confirm each other. The described analysis is performed for a number of important cases whose comparison allows us to gain an advanced understanding of the system behaviour: We distinguish the critical and off-critical case that correspond to zero and non-zero mean concentration, respectively. In the critical case the investigation focuses on (i) flat films without surface bias, (ii) flat films with surface bias, (iii) height-modulated films without surface bias, and (iv) height-modulated films with surface bias. Each case is analysed for several mean film heights and (if applicable) energetic bias at the free surface using the lateral domain size as main control parameter. Linear stability analyses of layered films and symmetry considerations are used to understand the structures of the determined bifurcation diagrams. For off-critical mixtures our study is more restricted. There we consider height-modulated films without and with surface bias for several mean film heights and (if applicable) energetic bias employing the mean concentration as main control parameter.

Die vorliegende Arbeit beschaeftigt sich mit der Herleitung, Analyse und Numerik von reduzierten Systemen gewoehnlicher Differenzialgleichungen (bezeichnet als reduzierte Modelle), die einer Familie von eindimensionalen Schmierfilmgleichungen (lubrication equations) entsprechen. Diese Familie wurde von Muench et al. 06'' hergeleitet und beschreibt den Entnetzungsprozess von nanoskopischen duennen Fluessigkeitsfilmen auf hydrophoben Polymersubstraten als Folge von anziehenden van der Waals und abstossenden Born Intermolekularkraeften. Dabei wurden verschiedene Regime von Schlupf-Laengen auf der Grenzflaeche zwischen Fluessigkeit und Polymersubstrat betrachtet. Die letzte Phase des Entnetzungsprozesses ist durch eine sehr langsame Vergroeberungsdynamik der verbleibenden Tropfen charakterisiert. Reduzierte Modelle, hergeleitet aus den zugrunde liegenden Schmierfilmgleichungen, ermoeglichen die effiziente analytische und numerische Untersuchung des Vergroeberungsprozesses. Im ersten Teil dieser Studie leiten wir unter Verwendung von asymptotischen Methoden reduzierte Modelle fuer verschiedene Schmierfilmgleichungen ab. Der zweite Teil dieser Studie widmet sich einer neuen Methode fuer die Herleitung und die Begruendung solcher reduzierter Modelle. Diese Methode basiert auf der Idee der Reduktion auf eine Zentrumsmannigfaltigkeit. Zuerst beschreiben wir eine formale Reduktion auf eine sogenannte "approximative invariante" Mannigfaltigkeit. Danach betrachten wir die Linearisierung der Schmierfilmgleichung um den stationaeren Tropfen. Hier geben wir eine rigorose Herleitung fuer das asymptotische Verhalten des Spektrums bezuglich des kleinen Parameters epsilon. Fuer das entsprechende Eigenwertproblem belegen wir die Existenz von einer von epsilon abhaengigen Luecke im Spektrum, die eine wichtige Eigenschaft fuer die strenge Begruendung unserer formalen Reduktion auf die "approximative invariante" Mannigfaltigkeit ist.
In this dissertation the topic of reduced ODE models corresponding to a family of one-dimensional lubrication equations derived by Muench et al. 06'' is addressed. This family describes the dewetting process of nanoscopic thin liquid films on hydrophobic polymer substrates due to the presence of several intermolecular forces and takes account of different ranges of slip-lengths at the polymer substrate interface. Reduced ODE models derived from underlying lubrication equations allow for an efficient analytical and numerical investigation of the latest stage of the dewetting process: coarsening dynamics of the remaining droplets. We first give an asymptotical derivation of these models and use them to investigate the influence of slip-length on the coarsening dynamics. In the second part of the talk we present a new geometric approach which can be used for an alternative derivation and justification of above reduced ODE models and is based on a center-manifold reduction recently applied by Mielke and Zelik 08'' to a certain class of semilinear parabolic equations. One of the main problems for a rigorous justification of this approach is investigation of the spectrum of a lubrication equation linearized at the stationary solution, which describes physically a single droplet. The corresponding eigenvalue problem turns out to be a singularly perturbed one with respect to a small parameter epsilon tending to zero. For this problem we show existence of an epsilon-dependent spectral gap between a unique exponentially small eigenvalue and the rest of the spectrum.

Dans ce manuscrit, un modèle complet pour la simulation de l'écoulement d'un fluide thermor éactif à travers un milieu poreux fortement compressible est présenté. Ce modèle est utilisé pour l'étude des procédés d'élaboration des matériaux composites par infusion à travers leur épaisseur (Liquid Resin Infusion-LRI et Resin Film Infusion-RFI ). Dans ces procédés, le mélange entre les renforts et la résine liquide est réalisé dans la direction transverse aux plans des préformes pendant la phase de mise en forme. Les coˆuts sont ainsi réduits et les problèmes de remplissage éliminés. Ces procédés sont néanmoins peu maîtrisés et les caractéristiques de la pièce finale difficilement prévisibles (principalement les épaisseurs et les porosités). La mise au point d'un modèle numérique constituerait un bon outil pour développer et finaliser de nouvelles solutions composites. D'un point de vue physique, l'infusion de la résine à travers l'épaisseur des préformes est une conséquence de la pression appliquée sur l'empilement résine/préforme. Dans cette analyse multi-physique deux types de problèmes sont rencontrés. Tout d'abord, on connait mal les conditions de couplage entre les zones liquides, gouvernées par les équations de Stokes, et les préformes imprégnées assimilées à des milieux poreux, gouvernées par une loi de Darcy et une loi de comportement mécanique non-linéaire. Par ailleurs, les interactions entre l'écoulement de la résine et la compression des préformes ne sont pas bien maîtrisées. Le modèle développé inclut donc une condition de Beaver-Joseph- Schaffman modifiée pour le couplage entre les zones de Darcy et de Stokes. Une formulation ALE pour l'écoulement de la résine dans un milieu poreux déformable subissant de fortes déformations est utilisée et couplée à une formulation Lagrangienne Réactualisée pour la partie solide. Ces deux mécanismes physiques sont couplés à des modèles thermo-chimiques pour traiter la réticulation de la résine sous l'action du cycle de température. Dans ce travail, un certain nombre d'outils numériques et de nouvelles formulations ont été développés en vue de simuler les procédés LRI et RFI. Chaque outil est étudié et validé analytiquement ou numériquement avant d'être intégré dans les modèles LRI /RFI. Des simulations numériques d'infusion sont ensuite présentées et commentées, puis une première comparaison avec des essais expérimentaux est proposée.

The explosive development of the telecom industry and in particular wireless and mobile communications in recent years has lead to a rapid development of new component and fabrication technologies to continually satisfy the mutually exclusive requirements for better performance and miniaturization on the one hand and low cost on the other. A fundamental element in radio communications is time and frequency control, which in turn is achieved by high performance electro-acoustic components made on piezoelectric single crystalline substrates. The latter, however, reach their practical limits in terms of performance and cost as the frequency of operation reaches the microwave range. Thus, the thin film electro-acoustic technology, which uses thin piezoelectric films instead, has been recently developed to alleviate these deficiencies. This thesis explores and addresses a number of issues related to thin film synthesis on the one hand as well as component design and fabrication on other. Specifically, the growth of highly c-axis textured AlN thin films has been studied and optimized for achieving high device performance. Perhaps, one of the biggest achievements of the work is the development of a unique process for the deposition of AlN films with a mean c-axis tilt, which is of vital importance for the fabrication of resonators operating in contact with liquids, i.e. biochemical sensors. This opens the way for the development of a whole range of sensors and bio-analytical tools. Further, high frequency Lamb wave resonators have been designed, fabricated and evaluated. Performance enhancement of FBAR devices is also addressed, e.g. spurious mode suppression, temperature compensation, etc. It has been demonstrated, that even without temperature compensation, shear mode resonators operating in a liquid still exhibit an excellent performance in terms of Q (200) and coupling (~1.8%) at 1.2 GHz, resulting in a mass resolution better than 2 ng cm-2 in water, which excels that of today’s quartz sensors.

This thesis describes the unstable dynamics of a gas jet impinging on a falling liquid film. This flow configuration is encountered in the jet wiping process, used in continuous coating applications such as the hot-dip galvanizing to control the thickness of a liquid coat on a moving substrate. The interaction between these flows generates a non-uniform coating layer, of great concern for the quality of industrial products, and results from a complex coupling between the interface instabilities of the liquid film and the confinement-driven instabilities of the impinging jet.Combining experimental and numerical methods, this thesis studied the dynamics of these flows on three simplified flow configurations, designed to isolate the key features of their respective instabilities and to provide complementary information on their mutual interaction. These configurations include the gas jet impingement on a falling liquid film perturbed with controlled flow rate pulsation, the gas jet impingement on a solid interface reproducing stable and unstable liquid film interfaces and a laboratory scaled model of the jet wiping process. Each of these configurations was reproduced on dedicated experimental set-up, instrumented for non-intrusive measurement techniques such as High-Speed Flow Visualization (HSFV) and Time-resolved Particle Image Velocimetry (TR-PIV) for the gas jet flow analysis, Laser Induced Fluorescence (LIF) tracking of the liquid interface, and 3D Light Absorption (LAbs) measurement of the liquid film thickness. To optimize the performances of these measurement techniques, several advanced data processing routines were developed, including a novel image pre-processing method for background removal in PIV and a dynamic feature tracking for the automatic detection of the jet flow and the liquid film interface from HSFV, LIF, and PIV videos.To identify the flow structures driving the unstable response of the jet flow, a novel data-driven modal decomposition was developed. This decomposition, referred to as Multiscale Proper Orthogonal Decomposition (mPOD), was validated on synthetic, numerical and experimental test cases and allowed for better feature extraction than classical alternatives such as Proper Orthogonal Decomposition (POD) or Dynamic Mode Decomposition (DMD).The experimental work on these laboratory models was complemented with the analysis of several numerical simulations, including a classical 2D Unsteady Reynolds Averaged Navier Stokes (URANS) modeling of the gas jet impingement on a fixed interface, a 2D Variational Multiscale Simulation (VMS) with anisotropic mesh refinement of the gas jet impingement on a pulsing interface, and a 3D simulation of the jet wiping process combining Large Eddy Simulation (LES) on the gas side with Volume of Fluid (VOF) treatment of the liquid film flow. The experimental modal analysis on the dynamic response of the gas jet and the characterization of the pressure-velocity coupling in the numerical investigation allowed for a complete picture of the mechanism driving the jet oscillation and its possible impact on the liquid film.In parallel, several flow control strategies to prevent the jet oscillation were developed, tested numerically and experimentally in simplified conditions, and later implemented on the design of a new nozzle for the jet wiping process. This new nozzle was finally tested on a laboratory scale of the wiping process and its performances compared to single jet and multiple jet wiping configurations. In these three cases, the experimental work presents the modal analysis of the gas field using TR-PIV and mPOD, the liquid interface tracking via LIF, and the final coating thickness characterization via LAbs.The large spatiotemporally resolved experimental database allowed to give a detailed description of the jet wiping instability and to provide new insights on this fascinating fundamental and applied problem of fluid dynamics.
Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished

With the rise of nanotechnology in the last decade, nanofluidics has been established as a research field and gained increased interest in science and industry. Natural aqueous nanofluidic systems are very complex, there is often a predominance of liquid interfaces or the fluid contains charged or differently shaped colloids. The effects, promoted by these additives, are far from being completely understood and interesting questions arise with regards to the confinement of such complex fluidic systems. A systematic study of nanofluidic processes requires designing suitable experimental model nano – channels with required characteristics. The present work employed thin liquid films (TLFs) as experimental models. They have proven to be useful experimental tools because of their simple geometry, reproducible preparation, and controllable liquid interfaces. The thickness of the channels can be adjusted easily by the concentration of electrolyte in the film forming solution. This way, channel dimensions from 5 – 100 nm are possible, a high flexibility for an experimental system. TLFs have liquid IFs of different charge and properties and they offer the possibility to confine differently shaped ions and molecules to very small spaces, or to subject them to controlled forces. This makes the foam films a unique “device” available to obtain information about fluidic systems in nanometer dimensions. The main goal of this thesis was to study nanofluidic processes using TLFs as models, or tools, and to subtract information about natural systems plus deepen the understanding on physical chemical conditions. The presented work showed that foam films can be used as experimental models to understand the behavior of liquids in nano – sized confinement. In the first part of the thesis, we studied the process of thinning of thin liquid films stabilized with the non – ionic surfactant n – dodecyl – β – maltoside (β – C₁₂G₂) with primary interest in interfacial diffusion processes during the thinning process dependent on surfactant concentration 64. The surfactant concentration in the film forming solutions was varied at constant electrolyte (NaCl) concentration. The velocity of thinning was analyzed combining previously developed theoretical approaches. Qualitative information about the mobility of the surfactant molecules at the film surfaces was obtained. We found that above a certain limiting surfactant concentration the film surfaces were completely immobile and they behaved as non – deformable, which decelerated the thinning process. This follows the predictions for Reynolds flow of liquid between two non – deformable disks. In the second part of the thesis, we designed a TLF nanofluidic system containing rod – like multivalent ions and compared this system to films containing monovalent ions. We presented first results which recognized for the first time the existence of an additional attractive force in the foam films based on the electrostatic interaction between rod – like ions and oppositely charged surfaces. We may speculate that this is an ion bridging component of the disjoining pressure. The results show that for films prepared in presence of spermidine the transformation of the thicker CF to the thinnest NBF is more probable as films prepared with NaCl at similar conditions of electrostatic interaction. This effect is not a result of specific adsorption of any of the ions at the fluid surfaces and it does not lead to any changes in the equilibrium properties of the CF and NBF. Our hypothesis was proven using the trivalent ion Y3+ which does not show ion bridging. The experimental results are compared to theoretical predictions and a quantitative agreement on the system’s energy gain for the change from CF to NBF could be obtained. In the third part of the work, the behavior of nanoparticles in confinement was investigated with respect to their impact on the fluid flow velocity. The particles altered the flow velocity by an unexpected high amount, so that the resulting changes in the dynamic viscosity could not be explained by a realistic change of the fluid viscosity. Only aggregation, flocculation and plug formation can explain the experimental results. The particle systems in the presented thesis had a great impact on the film interfaces due to the stabilizer molecules present in the bulk solution. Finally, the location of the particles with respect to their lateral and vertical arrangement in the film was studied with advanced reflectivity and scattering methods. Neutron Reflectometry studies were performed to investigate the location of nanoparticles in the TLF perpendicular to the IF. For the first time, we study TLFs using grazing incidence small angle X – ray scattering (GISAXS), which is a technique sensitive to the lateral arrangement of particles in confined volumes. This work provides preliminary data on a lateral ordering of particles in the film.
Mit dem Heranwachsen der Nanotechnologie in den vergangenen zehn Jahren hat sich die Nanofluidik als Forschungsbereich etabliert und erfährt wachsende Aufmerksamkeit in der Wissenschaft, sowie auch in der Industrie. Im biomedizinischen Bereich, wo intrazelluläre Prozesse häufig komplexer, nanofluidischer Natur sind, wird sich vermehrt für ein detailliertes Verständnis von nanofluidischen Prozessen interessiert, z.B. für den Einfluss von Kolloiden verschiedenster Form oder elektrischer Ladung auf die Kanäle und auf das Fließverhalten oder die Auswirkungen der Einengung von Flüssigkeiten und Kolloiden in Nanometer Geometrien. In der vorliegenden Arbeit werden dünne flüssige Filme, hinsichtlich ihrer Funktion als nanofluidische Modelle untersucht. Im ersten Teil der Arbeit wurde die Fließgeschwindigkeit des Fluids aus dem dünnen Film, abhängig von der Konzentration der filmstabilisierenden Tensidmoleküle n – Dodecyl β – D – Maltoside ( β – C₁₂G₂) bei einer konstanten Elektrolytkonzentration von 0.2 mM NaCl untersucht. Mit einem theoretischen Modell konnte das Dünnungsverhalten nachgezeichnet werden. Es wurde eine kritische Tensidkonzentration gefunden, unter der die Oberflächen lateral mobil sind und über der sie sich wie fest verhalten. Dadurch konnten wir Aufschluss darüber erlangen, wie die Oberfläche des Films unter verschiedenen Bedingungen geschaffen ist, und das in Bezug zur Verteilungsdichte der Moleküle an den Oberflächen setzen. Im weiteren wurden komplexere, nanofluidische Systeme untersucht, wobei zum einen ~ 1 nm lange, stäbchenförmige, multivalent geladene Spermidin - Moleküle die punktförmigen Elektrolyte ersetzten. Es konnte eine deutliche Veränderung der Stabilität zwischen Filmen mit und ohne Stäbchen festgestellt werden. Die Filme, mit NaCl, blieben länger in dem metastabilen „Common Film“ (CF) Zustand als die Filme, die eine vergleichbare Konzentration von Spermidin Stäbchen beinhalteten. Die Ergebnisse deuteten auf eine zusätzliche Anziehungskraft durch Brückenbildung zwischen zwei geladenen Oberflächen durch gegensätzlich geladene Stäbchenförmige Moleküle hin. Es konnte gezeigt werden, dass dieser Effekt weder ein Ergebnis von spezifischer Ionenadsorption an die Filmoberfläche war, noch ein Unterschied in den Gleichgewichtszuständen von den Dicken der CFs und der Newton Black Films (NBFs) hervorrief, was auf die korrekte Annahme der Ionenstärke in der Lösung schließen ließ. Auch in Versuchen mit ebenfalls trivalenten Ionen YCl3 wurde festgestellt, dass kein vergleichbarer Überbrückungseffekt auftritt. Die Ergebnisse wurden mit theoretischen Simulationen verglichen und es wurde eine quantitative Übereinstimmung gefunden bezüglich der Größe des Systeminternen Energiegewinns durch den Überbrückungseffekt. Desweiteren wurde das Fließverhalten von Fluiden mit Kolloiden eingeengt in Nanometer Geometrien untersucht. Für zwei verschiedene Arten von Nanopartikeln (Fe3O4 stabilisiert mit Oleinsäure und polymerstabilisierte Goldpartikel) wurde eine Verlangsamung der Fließgeschwindigkeit festgestellt. Mit einem theoretischen Modell konnte das Fließverhalten nur für enorm erhöhte Viskositätswerte des Fluids erklärt werden. Die Viskositätserhöhung wurde mit Partikelaggregaten, die den Ausfluss behindern, erklärt und diskutiert, unter der Annahme eines nicht - Newtonischen Fließverhaltens der Dispersionen. Gleichermaßen wurde die strukturelle Anordnung der Partikel in den Filmen hinsichtlich ihrer vertikalen und lateralen Verteilung untersucht. In dieser Arbeit werden vorläufige Ergebnisse präsentiert, die noch weiteren Studien bedürfen. Mit Neutronenreflexion sollte die Anordnung der Partikel orthogonal zur Oberfläche im Film analysiert werden. Eine qualitative Analyse lässt schließen, dass bei einer höheren Konzentration von Partikeln in Lösung, sich auch eine erhöhte Konzentration von Partikeln im dünnen Film befindet. Leider konnten die Daten nicht hinsichtlich der Lage der Partikel analysiert werden. Zum ersten Mal wurden dünne flüssige Filme mit Kleinwinkelröntgenstreuung unter streifendem Einfall (GISAXS) analysiert. Mit Hilfe dieser Methode sollte eine laterale Anordnung der Partikel im Film untersucht werden. Es konnten erfolgreiche Messungen durchgeführt werden und mit Hilfe der rechnergestützten Analyse konnte eine Aussage gemacht werden, dass ~ 6 nm große Teilchen in ~ 43 nm Abstand sich im Film befinden. Die Aussage bezüglich der kleinen Teilchen könnte sich auf einzelne, kleinere Partikel beziehen, allerdings könnten auch die 43 nm eine relevante Strukturgröße darstellen, da es in der Dispersion gehäuft Aggregate mit dem Durchmesser in dem Größenbereich vorliegen. Zusammenfassend können sich mit dieser Arbeit die dünnen flüssigen Filme als eine wichtige Kernmethode der Untersuchung von nanofluidischen Prozessen, wie sie häufig in der Natur vorkommen, behaupten.

Дисертаційна робота присвячена дослідженню закономірностей процесу концентрування водних розчинів малолетких рідин у стікаючій плівці випаровуванням в перехресний потік нейтрального газу і використанню результатів цих досліджень для створення нової конструкції концентратора та методики його розрахунку. Такий концентратор дозволяє проводити безвакуумне концентрування розчинів при температурі нижче температури їх кипіння, що, зважаючи на високі температури кипіння мололетких рідин, дає можливість знизити енерговитрати й відмовитися від дефіцитних видів палива, що використовується для нагрівання розчину. Відповідно до мети та поставлених задач, дослідження мали характер комплексних, оскільки були використані як теоретичні так експериментальні методи, які знайшли своє застосування у концентруванні водних розчинів. Теоретичні дослідження проводили використовуючи метод математичного моделювання, який полягав у формулюванні спрощених фізичних уявлень про процеси, що вивчаються, і опис їх системою диференційних та інтегральних рівнянь. Розрахунки, пов'язані з моделюванням і обробкою експериментальних даних проводили за допомогою програмного забезпечення Microsoft Excel, Mathcad. У дисертації наведені результати моделювання гідродинаміки і тепломасоперенесення стікаючої плівки індивідуальної (однокомпонентної) рідини, що випаровується в перехресний потік нейтрального газу з використанням розробленої математичної моделі. Ці результати показали закономірності зміни товщини, швидкості стікання і температури плівки за її довжиною, а також температури газу над плівкою. Встановлено, що інтенсивність випаровування рідини з плівки при її перехресному напрямку руху щодо газового потоку більше, ніж при прямоточному напрямку і може перевищувати інтенсивність випаровування при протиточному напрямку. Температура плівки рідини, що випаровується в перехресний потік нейтрального газу, при віддаленні від її початкового перерізу досягає усталеного значення, а при подальшому збільшенні відстані від цього перерізу рідина повністю випаровується. Розроблено алгоритм розрахунку відстаней, на яких відбуваються ці явища. Температура газу над плівкою за довжиною плівки змінюється несуттєво, але за своїм характером ця зміна відповідає зміні температурі плівки, і також досягає усталеного значення. В ході експериментальних досліджень використовували методи фізичного моделювання із застосуванням теорії подібності, статистичної обробки експериментальних даних. Вхідні та вихідні параметри досліджуваних процесів на експериментальній установці визначали манометричним, термометричним і об'ємним методами вимірювання. А концентрацію водних розчинів гліцерину, який використовувався в якості модельної рідини, вимірювали ареометричним і рефрактометричним методами. На підставі експериментального дослідження тепломасоперенесення в стікаючій плівці води, що випаровується в перехресний потік повітря, встановлені значення коефіцієнта тепловіддачі від поверхні до стікаючої з неї плівки, а також коефіцієнтів тепло – і масовіддачі від плівки до повітряного потоку. Показано, що залежності коефіцієнтів тепло – і масовіддачі від початкового потоку рідини проходять через мінімум, відповідний 𝑅𝑒ж≈500, що свідчить про перехід від ламінарного режиму течії плівки до турбулентного в умовах, що розглядаються. Встановлено залежність цих коефіцієнтів від параметрів процесу тепломасоперенесення для обох режимів. На підставі математичної обробки експериментальних даних були отримані емпіричні рівняння для їх розрахунку. Отримані результати математичного моделювання та експериментального дослідження випаровування індивідуальної рідини зі стікаючої її плівки стали основою для розробки математичної моделі і дослідження процесу концентрування водних розчинів малолетких рідин в стікаючій плівці випаровуванням в перехресний потік нейтрального газу. За допомогою цієї моделі встановлено закономірності зміни складу розчину за довжиною плівки та інтенсивності процесу концентрування. Показано, що концентрація розчину на початку плівки змінюється лінійно, потім відбувається її різкий підйом, що триває до повного випаровування води. Такий характер зміни концентрації розчину за довжиною плівки пов'язаний з розподілом температури плівки. Різкий підйом концентрації відповідає усталеному значенню температури. Встановлено, що інтенсивність процесів концентрування зростає зі зменшенням початкового потоку розчину і його початкової концентрації, а також зі збільшенням початкової температури розчину, температури поверхні стінки, на якій стікає плівка й початкової температури повітря, що надходить в простір над плівкою. Зі збільшенням швидкості повітря інтенсивність концентрування падає. Проведено експериментальне дослідження процесу концентрування водних розчинів гліцерину в їх стікаючій плівці в умовах випаровування в потік повітря, в результаті якого визначені коефіцієнти тепло – і масовіддачі, що являються параметрами розробленої математичної моделі. Встановлено, що в дослідженому діапазоні зміни параметрів процесу для низько концентрованих розчинів гліцерину, як і для води, характерний перехід від ламінарного режиму стікання плівки до турбулентного, для розчинів з підвищеною концентрацією гліцерину такий перехід відсутній і плівка стікає тільки в ламінарному режимі. У дисертації на основі експериментальних досліджень показано прояв капілярних ефектів за умов стіканні плівки рідини, що випаровується в перехресний газовий потік, який виражається зменшенням ширини плівки. Також встановлені закономірності цього зменшення для плівок води й водних розчинів гліцерину залежно від параметрів процесу стікання. Для води і водних розчинів гліцерину така зміна ширини плівки може досягати 50-80%. Найбільший вплив на зменшення ширини плівки за таких умов дають початковий потік рідини та температура поверхні стікання. Для коригування поверхні випаровування плівки, визначеної на основі технологічного розрахунку, була введена величина ширини середньої поверхні випаровування плівки. Результатами експериментального дослідження впливу параметрів процесу стікання плівки води й водних розчинів гліцерину на ширину середньої поверхні випаровування стали узагальнені емпіричні закономірності, що пов'язують коригувальний коефіцієнт з основними параметрами процесу стікання. На основі проведених в дисертаційній роботі теоретичних і експериментальних досліджень закономірностей стікання і тепломасоперенесення в плівці рідини, а також моделювання процесу концентрування водних розчинів малолетких рідин в стікаючій плівці розроблена нова конструкція і методика розрахунку плівкового концентратора таких розчинів. Конструкція заснована на використанні плоско–паралельної (пластинчастої) насадки, що дозволяє забезпечити перехресну взаємодію стікаючої плівки рідини з газовим потоком. Елементи насадки (пластини) мають внутрішні порожнини, де проходить теплоносій, що нагріває плівку розчину, яка стікає з її зовнішньої поверхні. Методика розрахунку випробувана на конкретному прикладі розрахунку концентратора водного розчину гліцерину. Її апробація показала, що для підвищення концентрації цього розчину від 6 до 30% (мас.) з продуктивністю в 2,0 т/год необхідна робоча висота плоско – паралельної насадки рівна 1,62 м. Розроблену методику розрахунку такого апарату та ескізний проект на концентратор прийнятий Державним науково – дослідним інститутом хімічних продуктів у розробку директивного технологічного процесу та проектування фази регенерації відпрацьованої кислотної суміші виробництва нітратів целюлози. Результати дисертаційних досліджень впроваджені в учбовий процес при викладанні дисциплін "Процеси і апарати хімічних виробництв" та "Технологія виробництва спеціальних високомолекулярних сполук" на кафедрі хімічної технології високомолекулярних сполук Шосткинського інституту СумДУ.
The thesis is devoted to the study of the regularities of the process of concentration of aqueous solutions of some low–volatile liquids in a flowing diaper by evaporation into a cross flow of neutral gas and the use of the results to create a new kind of the concentrator. Such kind of a concentrator makes possible vacuum–free concentration of solutions at temperatures below their boiling point, which, due to the high boiling points of volatile liquids, helps to reduce energy consumption and to avoid the scarce types of fuel used while heating the solution. The thesis presents the results of modeling the hydrodynamics and heat and mass transferring of a flowing film of an individual (of one component) liquid evaporating into a cross flow of a neutral gas using the created mathematical model. The results demonstrate the regularities of changes in the thickness, flow rate and temperature of the film along its length, as well as the temperature of the gas above the film. It was found that the intensity of evaporation of liquid from the film during its cross–interaction with the gas flow is higher than during direct–flow interaction and can exceed the rate of evaporation during counter current interaction. The temperature of a liquid film evaporating into a cross flow of a neutral gas, with distance from its initial cross section, reaches an equilibrium value, and with a further increasing the distance from this section, the liquid evaporates completely. There has been developed an algorithm for calculating the distances at which these phenomena appear. The temperature of the gas above the film along the length of the film changes insignificantly, but by its natural characteristics this change is associated with the temperature of the film and reaches an equilibrium value, in addition. On the basis of an experimental study of heat and mass transfer in a flowing film of water evaporating into a cross flow of air, the values of the heat transfer coefficient from the surface to the film flowing along it, as well as the coefficients of heat and mass transfer from the film to the air flow, have been established. The dependence of these coefficients on the parameters of the heat and mass transfer process showed the presence of a transition from the laminar mode of film flow to the turbulent one at the value of the number 𝑅𝑒ж≈500. Mathematical processing of the experimental data made it possible to obtain empirical equations for calculating the heat and mass transfer coefficients. The obtained results of mathematical modeling and experimental study of the evaporation of an individual liquid from its flowing down film became the basis for the development of a mathematical model and study of the process of concentration of aqueous solutions of some low–volatile liquids in a flowing film by evaporation into a cross flow of neutral gas. Using this model, the regularities of changes in the composition of the solution along the length of the film and the intensity of the concentration process were established. It is shown that the concentration of the solution at the beginning of the film changes linearly, then there is a abrupt rise, continuing until the complete evaporation of water. This kind of a change in the concentration of the solution along the length of the film is associated with the temperature distribution of the film. The abrupt rise of concentration corresponds to the state temperature value. An experimental study of the process of concentration of aqueous solutions of glycerin in their flowing film in the conditions of evaporation into an air stream was carried out, as a result of which the heat and mass transfer coefficients were determined, which are the parameters of the developed mathematical model. It was found that, in the investigated range of variation of the process parameters, for low–concentration solutions of glycerol, as well as for water, it is common to observe the transition from a laminar mode of film flow to a turbulent one, for solutions with an increased concentration of glycerol, such a transition is absent and the film flows down only in a laminar mode. The thesis presents experimental data on a decrease in the width of a liquid film flowing down a heated flat surface, associated with capillary effects. For water and aqueous solutions of glycerin, such a change in the width of the film can reach 50-80%. The natural characteristic of the change in the width of the film along its length and the obtained empirical dependences for its assessment are established. On the basis of the results obtained in the thesis, the study of the process of concentrating aqueous solutions of some low–volatile liquids, a new design and method for calculating a film concentrator have been developed. The design is based on the use of a plane–parallel (lamellar) packing, which makes possible a cross–flow interaction. The elements (plates) of the packing have internal cavities through which the coolant passes, heating the solution film flowing down their outer surface. The calculation technique was tested on specific parameters of the concentration process.

Even though titanium dioxide photocatalysis has been promoted as a leading green technology for water purification, many issues have hindered its application on a large commercial scale. For the materials scientist the main issues have centred the synthesis of more efficient materials and the investigation of degradation mechanisms; whereas for the engineers the main issues have been the development of appropriate models and the evaluation of intrinsic kinetics parameters that allow the scale up or re-design of efficient large-scale photocatalytic reactors. In order to obtain intrinsic kinetics parameters the reaction must be analysed and modelled considering the influence of the radiation field, pollutant concentrations and fluid dynamics. In this way, the obtained kinetic parameters are independent of the reactor size and configuration and can be subsequently used for scale-up purposes or for the development of entirely new reactor designs. This work investigates the intrinsic kinetics of phenol degradation over titania film due to the practicality of a fixed film configuration over a slurry. A flat plate reactor was designed in order to be able to control reaction parameters that include the UV irradiance, flow rates, pollutant concentration and temperature. Particular attention was paid to the investigation of the radiation field over the reactive surface and to the issue of mass transfer limited reactions. The ability of different emission models to describe the radiation field was investigated and compared to actinometric measurements. The RAD-LSI model was found to give the best predictions over the conditions tested. Mass transfer issues often limit fixed film reactors. The influence of this phenomenon was investigated with specifically planned sets of benzoic acid experiments and with the adoption of the stagnant film model. The phenol mass transfer coefficient in the system was calculated to be km,phenol=8.5815x10-7Re0.65(ms-1). The data obtained from a wide range of experimental conditions, together with an appropriate model of the system, has enabled determination of intrinsic kinetic parameters. The experiments were performed in four different irradiation levels (70.7, 57.9, 37.1 and 20.4 W m-2) and combined with three different initial phenol concentrations (20, 40 and 80 ppm) to give a wide range of final pollutant conversions (from 22% to 85%). The simple model adopted was able to fit the wide range of conditions with only four kinetic parameters; two reaction rate constants (one for phenol and one for the family of intermediates) and their corresponding adsorption constants. The intrinsic kinetic parameters values were defined as kph = 0.5226 mmol m-1 s-1 W-1, kI = 0.120 mmol m-1 s-1 W-1, Kph = 8.5 x 10-4 m3 mmol-1 and KI = 2.2 x 10-3 m3 mmol-1. The flat plate reactor allowed the investigation of the reaction under two different light configurations; liquid and substrate side illumination. The latter of particular interest for real world applications where light absorption due to turbidity and pollutants contained in the water stream to be treated could represent a significant issue. The two light configurations allowed the investigation of the effects of film thickness and the determination of the catalyst optimal thickness. The experimental investigation confirmed the predictions of a porous medium model developed to investigate the influence of diffusion, advection and photocatalytic phenomena inside the porous titania film, with the optimal thickness value individuated at 5 ìm. The model used the intrinsic kinetic parameters obtained from the flat plate reactor to predict the influence of thickness and transport phenomena on the final observed phenol conversion without using any correction factor; the excellent match between predictions and experimental results provided further proof of the quality of the parameters obtained with the proposed method.

Mestrado em Biotecnologia Molecular
This work proposes the study of the interactions, at a molecular level, between diverse ionic liquids (ILs) and the membrane cells, by applying membrane cell models, namely Langmuir-Blodgett technique. We intend to establish a better understanding about the role of the interactions of ILs with membrane cells, in specific, the imidazolium and choliniumcholinium families. Hence, we propose the evaluation of the effect of the concentration as well as of the alkyl chain lengths of imidazolium ILs, on the lipid monolayers organization and stability and compare it with the behaviour of choliniumcholinium ILs. Summing up, this work is expected to provide an insight into the molecular mechanism contributing to the IL toxic activity that should help in the design of less toxic ILs.
Este trabalho propõe o estudo das interações, ao nível molecular, entre diversos líquidos iónicos (ILs) e membranas celulares mediante a aplicação de modelos de membrana celular segundo a técnica de Langmuir Blodgett. Pretendemos estabelecer uma melhor compreensão sobre o papel fundamental das interações de ILs com as membranas celulares, em particular os ILs da família imidazólio e colina. Assim, propõe-se a avaliação do efeito da concentração, bem como dos comprimentos da cadeia alquílica de ILs da família imidazólio, na organização e estabilidade de monocamadas lipídicas e a comparação com o comportamento de líquidos iónicos da família das Colinas. Em suma, este trabalho pretende fornecer uma visão sobre os factores moleculares que contribuem para a toxicidade dos ILs, que possam ajudar no desenvolvimento de ILs menos tóxicos.

In der vorliegenden Arbeit wurde das Verhalten dünner Flüssigkeitsfilme an gekrümmten Substratoberflächen durch experimentelle Beschichtungsversuche basierend auf der non-invasiven laserinduzierten Fluoreszenzmesstechnik und durch numerische Filmsimulationen mit Hilfe des Volume-of-Fluid Mehrphasenmodells untersucht. Besonderes Interesse galt dabei dem Finden optimaler Einflussgrößenkombinationen zur Reduzierung des Fettkanten-Effekts. In der hierfür durchgeführten Parameterstudie wurden sowohl Applikationsparameter wie der Kantenrundungsradius und die Applikationsschichtdicke als auch Stoffparameter der untersuchten Flüssigkeit wie die Viskosität und die Oberflächenspannung variiert. Neben qualitativen Beschreibungen der entstandenen Fettkantengestalten sind als Resultate auch Größen zur Quantifizierung der Fettkanten festgelegt worden und systematisch dargestellt. Es konnte nachgewiesen werden, dass ungünstige und geeignete Parameterkonfigurationen existieren, welche prägnante bzw. kaum auffällige Fettkanten erzeugen, insbesondere im Experiment. Über die dabei eingreifenden Mechanismen der zugrundeliegenden Strömungen wurden konkrete Hypothesen aufgestellt, auch um die resultierenden Proportionalitäten der Fettkantengrößen bezüglich der Einflussgrößen zu plausibilisieren. Weiterhin konnte eine Aussage über die Signifikanz der untersuchten Einflussgrößen getroffen werden. Abschließend wurde eine geeignete dimensionslose Kenngröße generiert, um den Fettkanten-Effekt parameterübergreifend beschreiben zu können, wodurch mittels der Ähnlichkeitstheorie auch eine gewisse Abschätzung des Fettkanten-Effekts ermöglicht wird
In this study the behaviour of a thin liquid layer at a curved solid edge was examined by experimental coating investigations based on the laser-induced fluorescence technique and by numerical film simulations based on the Volume-of-Fluid multiphase flow model, respectively. The main motivation was to find optimal combinations of influencing quantities to reduce the fat-edge effect. Therefore a study of these quantities was performed, in which application parameters like edge radii of curvature and application layer thicknesses as well as determining liquid properties like viscosity and surface tension have been varied. Results are described qualitatively at corresponding fat-edge shapes and quantified by suitable fat-edge parameters, which had to be identified and selected. It could be shown that adverse and appropriate influencing parameter combinations exist, which generate conspicuous and less distinctive fat-edges, respectively - especially in laboratory experiments. The experimental findings and proportionalities regarding fat-edge shapes and dimensions are found to be physically plausible. Furthermore an order of significance of the influencing quantities established. Eventually, a dimensionless quantity was derived by dimensional analysis, which describes the fat-edge effect. Thus, the fat-edge effect has also been described by the application of similarity theory and the corresponding dimenionless number, respectively

When a high-temperature superconductor transitions in the presence of a magnetic field, the resistance does not immediately go to zero. Instead, the transition is smoothed by the resistive effects of moving vortices so that perfect conductivity isn't reached until several K below Tc, where the vortices have frozen into a glass state. The properties of this glass depend mainly on the amount and correlation between impurities in the superconductor. This report describes a study of the glass transition in an YBCO thin film rich in uncorrelated impurities. The aim was to use sensitive resistive measurements to determine which of two models of this transition, the vortex glass model and the vortex molasses model, is more accurate. After evaluation, both models are found lacking and a third model is put forth. This model, which resembles the normal distribution, excellently describes the YBCO thin film case. When the new model is tested against data from similar measurements, an YBCO single crystal and a TlBaCaCuO thin film, the results are mixed. Further study is suggested to determine the model's range of validity.

Room-Temperature Ionic Liquids (ILs) have attracted considerable interest in recent years. This interest is motivated by the physico-chemical properties of these systems, tunable modifying the chemical structure of ions. Generally, ILs show chemical and thermal stability, i.e. they do not easily decompose or react. Furthermore, these compounds remain liquid over an extended range of temperatures, in which they show also a remarkably low volatility. The low vapor pressure of ILs, promote them as good solvents for the growing field of the ”Green Chemistry”, in substitution of the volatile organic compounds. The fact that ILs are composed solely by ions, and can have a quite wide electrochemical window, make them very interesting as electrolytes. For these purposes, this PhD thesis is devoted to the investigation of ILs in contact with solid interfaces, primary targets of interaction. To deepen the analysis of electric properties at the solid interface, thin layers of ILs deposited on conductive substrates were investigated by means of AFM. The ”Green” character of these compounds was investigated studying their interaction with biomembrane models and external membranes of living cells, by means of AFM and electrochemical methods. Because of their ionic nature, ILs can be used as electrolytes in several devices aimed at conversion and storage of energy, such as electrochemical supercapacitors, Graetzel solar cells and batteries. In these devices a key role is played by the interface between the surface of the electrodes and the electrolyte; in particular, structural-morphological and electrical properties of the first few nanometers of IL interacting with the solid electrode surface are expected to have the strongest impact on device performance. AFM morphological analysis of small quantity of [C 4 MIM] [NTf 2 ] IL, deposited on various insulating surfaces revealed a population of nanodroplets and new structures. Remarkably, the solid surfaces induce the organization of the ionic liquid into regular, lamellar solid-like nanostructures presenting a high degree of vertical structural order and high mechanical resistance to normal compressive stresses. Nanomechanical investigation reveals that the structures resist to normal compressive loads up to 1.5 MPa; beyond that limit, indentation, in discrete steps, occurs. Furthermore, lamellar [C 4 MIM] [NTf 2 ] islands are not affected when scanned by a biased AFM tip under the influence of an electric field as intense as 10 8 V/m, while the liquid nano-and micro-droplets are easily swept away. These results confirm the solid-like character of the ordered lamellar nanostructures observed when thin films of [C 4 MIM] [NTf 2 ] are deposited on solid surfaces, and suggest that these films may possess an insulating, dielectric behavior, at odd with the case of the bulk ionic liquids. Nanoscale impedance measurements (capacitance vs. distance) and electrostatic force spectroscopy (electric force vs. distance) between a conductive AFM tip and the IL structures confirmed that values of the dielectric constant (ε r = 3-5) are significantly smaller than those measured in the bulk liquid (ε r = 9-15). These results support the picture of solid-like ordered domains where the ion mobility is significantly inhibited with respect to the bulk liquid phase. These findings also highlight the potentialities of scanning probe techniques for the quantitative investigation of the interfacial electrical properties of thin ionic liquid films, suggesting that ILs at electrified solid surfaces may possess unexpected electrical and structural properties, thus influencing the behavior of photo-electrochemical devices. The ”green” character of ionic liquids (ILs) is dependent on their negligible vapor pressure but in contrast to their environmental behavior their intrinsic toxicity is not at present completely understood. Accordingly, although ILs will not evaporate which alleviates air pollution problems, a potential hazard of Ils to living organisms via aqueous media cannot be ruled out. A rigorous investigation on the interaction of ILs with biomaterials is required to provide information about their intrinsic toxicity. In order to test the biocompatible character of ILs, as a first objective, the interaction of various ILs with biological membrane (biomembrane) models was studied using electrochemical methods. A series of imidazolium based ILs were investigated whose interactions highlighted the role of anion and lateral side chain of cation during the interaction with dioleoyl phosphatidylcholine (DOPC) monolayer. It was shown that the hydrophobic and lipophilic character of the IL cations is a primary factor responsible for this interaction. The modifications of the Hg supported monolayer caused by ILs were simultaneously monitored electrochemically in a well controlled manner using rapid cyclic voltammetry (RCV), alternating current voltammetry (ACV), and electrochemical impedance spectroscopy (EIS). Hg supported monolayers provide an accurate analysis of the behavior of ILs at the interface of a biomembrane leading to a comprehensive understanding of the interaction mechanisms involved. At the same time, these experiments show that the Hg-phospholipid model is an effective toxicity sensing technique as shown by the correlation between literature in vivo toxicity data and the data from this study. Cell membrane is the main target of ILs interaction, depending on the lipophilicity of hydrophobic lateral chain of cation. In order to test the biocompatible character of ILs, the interaction of various imidazolium-based ILs with supported DOPC phospholipid bilayers (as models of the cell membrane) and living MDA-MB-231 cells (@37 ◦C) was investigated. Atomic Force Microscopy (AFM) was used to carry on a combined topographic and mechanical analysis of supported DOPC bilayers as well as of living cells. During the analysis of DOPC bilayers we have observed modifications in breakthrough force and membrane elasticity related to the ingress of lateral chains of cations in the bilayer, demonstrating agreement with electrochemical results. The parallel nanomechanical analysis performed on living cells interacting with ILs at various concentrations showed modifications of elasticity (effective Young’s modulus) and morphology of cells after exposure to ILs dispersed in their culture medium. The measurements confirmed the primary action of ILs on membrane and actin cytoskeleton, highlighting a subtoxic/toxic effect dependent on ILs concentration and chemical nature of cation. Our results may be helpful for filling existing gaps of knowledge about ionic liquids toxicity and their impact on living organisms. From these evidences, interaction of ILs with micro-organisms and single cells is an important step to assess the environmental sustainability of this novel and promising class of solvents and to attribute a ”green” label to it. Studying the interaction of ionic liquids, it has been recognized that the interface is a vital component. When the bulk symmetry of IL is broken by surfaces, the electrical properties are greatly affected, leading from a ion conductor to an insulator behavior. Also the interaction with biological entity is driven, in first instance, by surface interaction. Biomembrane models and cell membranes are affected by ILs that accumulate/penetrate the surface interface, leading to structural reorganization/damage of external membrane.

Ce travail porte sur l’étude expérimentale et numérique de l’écoulement des mousses humides dans un canal horizontal droit de section carrée avec ou sans singularités. Il est consacré tout particulièrement à déterminer les paramètres pertinents de l’écoulement dont la chute de pression longitudinale, les champs de vitesse de l’écoulement de mousse en proche parois, les épaisseurs de films liquides minces et épais en paroi et l’évolution de la contrainte pariétale pour une mousse humide dont la fraction gazeuse varie de 55 à 85% et la vitesse débitante de la mousse est 2, 4 puis 6 cm/s. Une fois ces paramètres déterminés en conduite horizontale droite, nous avons ensuite effectué des mesures sur différentes géométries représentant un élargissement brusque, une chicane verticale et écoulement de mousse autour d’un cylindre, dont le but est d’étudier la réorganisation de l’écoulement en vue de déterminer le comportement rhéologique des mousses en écoulement à l’aval et à l’amont des singularités. Finalement, une étude de simulation numérique (CFD) en utilisant les lois de comportement de type Bingham, pour fluides non newtoniens, a été effectuée afin de tester sa capacité de représenter des écoulements type mousse humide dans une conduite horizontale avec ou sans singularités. Nous avons vérifié tout d’abord l’évolution longitudinale de la pression statique qui est linéaire à l’amont comme à l’aval loin des zones influencées par les singularités. La chute de pression singulière reste à peu près constante pour une vitesse débitante donnée de la mousse. À partir de la technique de Vélocimétrie par Image de Particule (PIV), nous avons déterminé les composantes de vitesse au voisinage immédiat des singularités. Ces mesures nous ont permis de mettre en évidence l’existence de différents régimes d’écoulement, et de déterminer la réorganisation et le comportement rhéologique de l’écoulement de mousse autour des géométries étudiées. L’analyse des mesures d’épaisseur de films liquides, obtenues par la méthode conductimétrique, indique que la paroi reste mouillée par un film liquide suffisamment épais pour qu’on puisse appliquer la méthode électrochimique. Les signaux polarographiques obtenus avec la mousse présentent alors de fortes fluctuations. La comparaison de celles-ci avec les contraintes pariétales déduites à partir des mesures de la chute de pression montre bien une bonne concordance. L’étude numérique (CFD), effectuée pour une fraction volumique de gaz égale à 70% et qui s’écoule avec une vitesse débitante de 2 cm/s, montre que le modèle rhéologique de Bingham pourrait être bien adapté à ce genre de mousse humide évoluant en écoulement en bloc
This work is an experimental and numerical study of aqueous foam flow inside a horizontal square duct, with and without flow disruption devices (fdd). It is especially devoted to determine the pertinent parameters of the flow: longitudinal pressure losses, velocity fields of foam flow near the walls, liquid film thickness (thick and thin), and the wall shear stress evolution, for an aqueous foam with a void fraction range between 55 and 85%, for a mean foam flow velocity of 2, 4 and 6 cm/s. Once they were determined, inside the horizontal channel, we carried out measurements over different geometries: half-sudden expansion, vertical fence and foam flow around a cylinder. The goal was to study the foam flow reorganization to well understand the rheological behavior of aqueous foam flow in the vicinities of different fdd. Finally, a numerical simulation (CFD), using the Bingham behavior model of non-Newtonian fluid, was undertaken to test its capacity to represent the aqueous foam flow inside the horizontal duct with flow disruption devices. First of all, we verified the static longitudinal pressure evolution, which varies linearly upstream and downstream far from the fdd. The singular pressure loss remains constant for a given mean foam velocity and a foam quality (void fraction). From the Particle Imaging Velocimetry (PIV) technique (2D), we determined the two velocity components in the immediate vicinities of the disruption devices. They allowed us to put into evidence the different foam flow regimes and to observe the foam flow reorganization and rheological behavior through the studied fdd. The slip-layer thickness analysis, obtained using the conductimetry method, shows that the wall presents a liquid film thick enough to apply an electrochemical technique (polarography). Thus, the polarographic signals, obtained for the foam flow, present important fluctuations. They were compared to the wall shear stress deducted from the measurement of pressure losses, showing a good similarity between them. The numerical study (CFD), carried out for aqueous foam flow with a void fraction of 70% and a mean foam flow velocity of 2 cm/s, shows that the Bingham rheological model can be adapted to this kind of aqueous foam flow which is flowing like a block

L'echange multiple decrit de maniere effective les proprietes magnetiques d'un systeme de fermions quasiment localises. Nous considerons ce modele pour des spins 1/2 sur le reseau triangulaire avec des processus a 2, 3, 4, 5 et 6 particules. Cet hamiltonien est aujourd'hui reconnu comme etant un bon candidat pour decrire le magnetisme nucleaire des films d'3he solide adsorbes sur du graphite. Nous l'etudions par diagonalisations exactes sur des echantillons jusqu'a 36 sites. Dans un large domaine de parametres, l'analyse des effets de taille finie sur les energies propres, la structure des spectres et les fonctions de correlation amenent a conclure que les fluctuations quantiques detruisent l'ordre magnetique a temperature nulle. L'etat fondamental est caracterise par une longueur de correlation finie, c'est un liquide de spins ou les excitations magnetiques possedent un gap. Nous calculons la chaleur specifique et trouvons une entropie importante a basse temperature, en accord avec les mesures experimentales. La reponse a un champ exterieur revele un plateau d'aimantation a m / m s a t = 1/2. Nous discutons les conditions d'apparition d'un tel plateau et les comparons avec les situations, mieux comprises, de la dimension un ainsi que celle de spins classiques. Pour le plus grand systeme etudie (36 sites), le fondamental possede une quasi-degenerescence quatre. Cette degenerescence ne s'explique pas par une brisure spontanee de symetrie mais elle conduit a une interpretation topologique. Nous suggerons une image de resonating valence-bond (rvb) a courte portee pour la fonction d'onde du fondamental et discutons du lien eventuel avec la phase de haldane et les etats de type valence-bond solid. Le modele d'echange multiple sur le reseau triangulaire semble un des tous premiers exemples d'hamiltonien bidimensionnel de spins 1/2 dont le fondamental ne brise aucune de symetrie a temperature nulle.

Grâce à leurs propriétés spécifiques (homogénéité de l'épaisseur, de la densité bidimensionnelle et de la tension), les films de cristaux liquides smectiques forment des membranes bidimensionnelles idéales obéissant à l'équation d'onde de Helmholtz, avec les conditions de Dirichlet au bord. Dans cette thèse, une nouvelle expérience a été mise au point, qui permet, pour un film tendu sur un contour donné, de mesurer non seulement son spectre de fréquences propres, mais aussi la forme géométrique des modes. Le rôle de la forme de la membrane a ainsi pu être analysé. On a commencé par étudier une forme "préfractale", constituée par une courbe de Koch quadratique, dont la construction a été arrêtée à un ordre d'itération fini. L'accord entre les résultats expérimentaux et des résultats numériques obtenus par d'autres auteurs, tant sur le spectre que sur l'allure des modes propres, est excellent. Deux mécanismes de localisation des fonctions d'onde, d'origines physiques différentes, ont été mis en évidence. L'autre question étudiée est un problème mathématique que l'on peut résumer par : "Peut-on entendre la forme d'un tambour?" La réponse prévue par les mathématiciens est "non", c'est-à-dire qu'il existe des formes géométriques différentes, conduisant à des spectres de fréquences propres identiques ; ces formes sont appelées "isospectrales". On a ainsi vérifié expérimentalement l'isospectralité de deux contours avec une bonne précision. On a également montré en détail que seules les symétries de construction de ces deux contours, basées sur la théorie des groupes, importaient.

Actuellement, de nombreuses equipes de recherche travaillent sur les sources laser bleues qui pourraient avoir un grand nombre d'applications. Le developpement de guides d'onde monocristallins apparait etre une approche interessante. En effet ce type de structure permet d'associer les proprietes des cristaux, a savoir des sections efficaces d'emission elevees, avec des effets de guidage et de confinement permettant de diminuer le seuil laser. Dans l'objectif d'obtenir des lasers guides d'onde fonctionnant par des mecanismes d'up-conversion, nous avons realise des couches minces monocristallines de liyf#4 dope terres rares (nd#3#+ ou tm#2#+) par epitaxie en phase liquide, sur des substrats monocristallins de liyf#4 non dope. La premiere partie de ce manuscrit decrit donc la croissance et la caracterisation physico-chimique des couches ainsi obtenues. Le probleme essentiel rencontre lors de la croissance de ces materiaux est leur tres grande reactivite vis a vis de l'oxygene et donc la formation d'une phase parasite genante pour les applications recherchees. La croissance de ces couches necessite donc des conditions de croissance tres severes (appareillage specifique, tres grande purete des matieres premieres, atmosphere controlee). Cette technique de croissance a permis d'obtenir des couches fortement concentrees en neodyme (jusqu'a 8% at. ). Le codopage des couches par du gadolinium a permis d'augmenter la difference d'indices entre la couche et le substrat et donc d'ameliorer le guidage. La deuxieme partie du manuscrit est consacree aux caracterisations optiques de ces couches : absorption, emission, dynamique de fluorescence. Nous avons egalement mis en evidence l'avalanche de photons, mecanisme d'up-conversion base sur une absorption a partir d'un etat excite. Ce mecanisme presente l'avantage de ne necessiter qu'un seul faisceau de pompe de lumiere rouge ou infrarouge pour obtenir une emission dans le visible (violet ou bleu dans le cas du neodyme ou du thulium). Nous avons donc etudie la dynamique de la fluorescence emise a 413 nm pour l'ion neodyme et a 450 ou 480 nm pour l'ion thulium. Un effet laser a ete obtenu a 1,05 m pour les couches dopees au neodyme. Les tests laser realises dans le bleu n'ont permis pour l'instant que d'obtenir une intense fluorescence bleue en mode guide.

The liquid fuel preparation has a strong impact on the combustion process and consequently on pollutant emissions. However, currently there are no validated and computational affordable methods available to predict the spray breakup process and to reliably compute the spray distribution generated after primary breakup. This research activity, carried out within the framework of the European project FIRST (Fuel Injector Research for Sustainable Transport), is aimed at developing reliable tools to be used in the industrial design process able to describe the processes involved in liquid fuel preparation in advanced injection systems based on prefilming airblast concept. A multi-coupled solver for prefilming airblast injectors which includes liquid film evolution and primary breakup was developed in the framework of OpenFOAM. The solver is aimed at improving the description of the complex physical phenomena characterizing liquid fuel preparation and spray evolution in advanced airblast injection systems within the context of typical RANS (U-RANS) industrial calculations. In this kind of injectors, gas-phase, droplet and liquid film interact with each other, thus, in order to properly predict spray evolution and fuel distribution inside the combustor, proper tools able to catch the most important interactions among the different phases are necessary. A steady-state Eulerian-Lagrangian approach was introduced in the code together with up-to-date evaporation and secondary breakup models. Particular attention was devoted to the liquid film primary breakup and to the interactions between gas-phase and liquid film. A new primary breakup model for liquid films, basically a phenomenological model which exploits liquid film and gas-phase solutions for the computation of spray characteristics after breakup, was developed and implemented in the code. Different formulations for the computation of droplet diameter after breakup were evaluated and revised on the basis of recent experimental findings. The multi-coupled solver was validated against literature test cases with detailed experimental measurements and eventually applied to the simulation of an advanced prefilming airblast injector based on the PERM concept in a tubular combustor configuration. The proposed approach allows us to better describe the fuel evolution in the injector region leading to a more comprehensive and physically consistent description of the phenomena regulating liquid fuel preparation compared to standard approaches which neglect the presence of liquid film and its interaction with both droplets and gas-phase.

碩士
國立中山大學
物理研究所
81
We investigate the Smectic-A → Hexatic-B phase transition on free－standing liquid crystal films of two-molecular layers theoretically in this study. The Bruinsma and Aeppli model in two dimension is studied with two coupled ＸＹ models which are corresponding to bond orientation order and herring－bone order, respectively. Through thouroughly Monte Carlo simula- tions, we find that the system can simultaneously establish the order of two parameters in a continuous transition and the heat－capacity anomaly is a sharp peak with critical exponent α, which is 0.39 approxi- mately. This result is close to that of the Smectic-A→ Hexatic-B phase transition experiment of two －mole- cular－layer free－standing liquid crystal films con- ducted by C. C. Huang et al.．Experimently, they find that the Smectic-A → Hexatic-B phase transition of two-layer nmOBC liquid crystal films is chracterized by a novel heat－capacity peak with critical exponent α＝ 0.30±0.05．

JEL Classification: M31
Channel governance is an important research topic in marketing. Both channel governance and control mechanisms will directly influence the behavior of channel members, and thus will affect the outcomes of channel governance. With the transformation of Chinese economy, people's ideology also will change. The effectiveness of traditional unilateral incentives, monitoring and enforcement mechanisms from one channel members against another is also being challenged, while the bilateral incentives, monitoring and enforcement mechanisms based on both parties have been paid more and more attention by channel members. In addition, as the impact of interdependence between channel members on the outcomes of channel governance is slowly perceived by scholars and validated with the resulting data, channel members are more inclined to reduce dependence on counterparties. Recently, Chinese liquor manufacturers represented by Luzhou Laojiao have embarked on innovative channel mode to resolve the conflict between channel members, and thus improve coordination between channel members. All these phenomena indicate that the mechanisms and instruments of channel governance are constantly extended in the channel governance practice. However, the effectiveness of these mechanisms and instruments on the governance outcomes has not been fully investigated, and the impact of the channel mode, the degree of interdependence between the manufacturers and distributors and other such factors on the relationship between channel governance mechanisms and governance outcomes also needs further clarification. This thesis takes Luzhou Laojiao and its distributors system for the studying the following three issues. First, we simultaneously include unilateral and bilateral channel governance mechanisms in the framework of channel governance to study the impact of the six channel governance mechanisms (unilateral and bilateral incentive, monitoring and enforcement) on the outcomes of channel governance. Second, based on the findings of existing literature, the relative dependence between manufacturers and distributors will also affect the outcomes of channel governance and will also moderate the relationship between specific channel governance mechanisms and the corresponding governance outcomes. Therefore, this thesis also studies the impact of such relative dependence between manufacturers and distributors on the outcomes of channel governance in Luzhou Laojiao and the moderating role of such interdependence on the relationship between channel governance mechanisms and outcomes investigated. Third, there are two typical channel modes in Luzhou Laojiao. One is traditional channel model and the other is innovative mode - QIQUAN model. The QIQUAN channel mode is significantly different from the traditional channel model in management, administration, operations and profits sharing, and in turn will have an impact on the outcomes of channel governance. Therefore, this thesis also studies the impact of channel model on the outcomes of channel governance in Luzhou Laojiao and the moderating role of the channel mode on the relationship between channel governance mechanism and outcomes investigated. The results show that: 1) whether the unilateral or bilateral governance mechanisms, they all have a significant impact on the coordination among channel members. Among them, the unilateral incentive has a significant negative correlation with the coordination among channel members; while the bilateral incentive and enforcement mechanisms have a significant positive correlation with the coordination among channel members. In addition, the bilateral enforcement mechanism has a significant negative correlation with the conflict among channel members. 2) The channel mode has a significant positive correlation with the coordination among channel members, which shows that the QIQUAN channel mode facilitates coordination among channel members. However, the relationship between the channel mode and the conflict among channel members is not significant. In addition, the QIQUAN channel mode also enhances positive correlation between the bilateral monitoring mechanism and the coordination among channel members and weakens the negative correlation between the unilateral enforcement and the conflict among channel members. 3) Neither dependence of manufacturers on distributors nor the dependence of distributors on the manufacturer is conducive to coordination among channel members, which will also increase the conflict among channel members. Moreover, such a relative dependence will also moderate the relationship between the channel governance mechanism and the corresponding outcomes. Through this study, it can complement the deficiency in study of a single or unilateral channel governance mechanism of the governance outcomes and broaden the depth and width in the study. Second, while examining the impact of the channel governance mechanism on the channel governance outcomes, we also study in an innovative manner the impact of the channel mode on the channel governance outcomes and explore the moderating role of the channel mode on the relationship between the governance mechanism and governance outcomes, which makes our results more realistic and our findings have more applications.
A governança dos canais de distribuição é um tópico importante na pesquisa em Gestão de Empresas. Quer a governança dos canais de distribuição quer os mecanismos de controlo irão influenciar o comportamento dos membros envolvidos, e deste modo irão afetar os resultados da governança do canal. A transformação da economia chinesa provoca mudanças na ideologia do povo chinês. A eficácia dos incentivos unilaterais tradicionais, os mecanismos de monitorização e “enforcement” por parte de um membro sobre outro membro estão a ser questionados, enquanto os incentivos bilaterais e os mecanismos de monitorização e “enforcement” discutidos pelas partes envolvidas têm recebido cada vez mais atenção. Por outro lado, como o impacto da interdependência entre os membros do canal e os resultados da governança são lentamente percebidos pelos académicos e necessitam de validação empíricas, os membros do canal estão mais inclinados para reduzir a dependência de contrapartes. Recentemente, os produtores chineses de licor representados pela Luzhou Laojiao iniciaram um modelo de canal de distribuição inovador para resolver os conflitos entre os membros, e deste modo melhorar a coordenação entre os diferentes membros participantes. Todos estes fenómenos indicam que os mecanismos e instrumentos de governança dos canais estão constantemente a ser postos em prova e melhorados na prática diária da governança dos canais. Contudo a eficácia destes mecanismos e instrumentos nos resultados da governança não foram totalmente investigados, e o impacto deste novo modelo de canal de distribuição, o grau de interdependência entre os produtores e os distribuidores e outros fatores que influenciam a relação entre os mecanismos de governança do canal e os resultados da governança também necessitam de maior clarificação. Esta tese toma a Luzhou Laojiao e o seu sistema de distribuição como base para investigar as seguintes três questões. Primeiro, incluímos em simultâneo mecanismos unilaterais e bilaterais de governança de canais no quadro da governança para estudarmos o impacto de seis mecanismos de governança (incentivos bilaterais e unilaterais, monitorização e “enforcement”) nos resultados da governança do canal. Segundo, tomando como base a literatura existente, a dependência relativa entre os produtores e os distribuidores afeta os resultados da governança do canal e irá moderar a relação entre mecanismos específicos da governança do canal e os resultados correspondentes da governança. Deste modo, esta tese estuda também o impacto dessa dependência relativa entre produtores e distribuidores nos resultados da governança do canal de distribuição da Luzhou Laojiao e o papel moderador dessa interdependência na relação entre a governança do canal e os resultados investigados. Terceiro, existem dois modelos típicos de canais na Luzhou Laojiao. Um é o modelo tradicional e o outro é modelo inovador – o modelo QIQUAN. Este modelo é significativamente diferente do modelo tradicional em termos de gestão, administração, partilha de operações e de lucro, e por isso vai ter um impacto nos resultados da governança do canal. Deste modo esta tese também estuda o impacto do modelo de canal nos resultados da governança na Luzhou Laojiao e o papel moderador do modelo de canal na relação entre os mecanismos de governança do canal e os resultados investigados. Os resultados mostram que: 1) os mecanismos unilaterais e bilaterais de governança têm um impacto muito importante na coordenação entre os membros do canal. Entre eles, o incentivo unilateral tem uma forte correlação negativa com a coordenação entre membros do canal; enquanto os incentivos bilaterais e os mecanismos de “enforcement” têm uma forte correlação positiva com a coordenação entre os membros do canal. Além disso, o mecanismo de “enforcement” bilateral tem uma forte correlação negativa com o conflito entre membros do canal. 2) O modelo de canal tem uma forte correlação positiva com a coordenação entre os membros do canal, o que mostra que o modelo de canal QIQUAN facilita a coordenação entre os membros. Contudo, a relação entre o modelo de canal e o conflito entre os seus membros não é muito significante. Por outro lado, o modelo de canal QIQUAN melhora também a correlação positiva entre os mecanismos bilaterais de monitorização e a coordenação entre os membros do canal e enfraquece a correlação negativa entre o “enforcement” unilateral e o conflito entre os membros. 3) Nem a dependência dos produtores nos distribuidores nem a dependência dos distribuidores nos produtores conduz à coordenação entre os membros do canal, o que aumenta o conflito entre os membros do canal. Além disso, esta dependência relativa irá moderar a relação entre os mecanismos de governança do canal e os resultados correspondentes. Este estudo, ao incluir simultaneamente mecanismos unilaterais e bilaterais de governança aprofunda e alarga os estudos existentes. Por outro lado, ao estudamos o impacto dos mecanismos de governança do canal nos resultados da governança, estamos a estudar de uma maneira inovadora o impacto do modelo de canal nos resultados da governança e a explorar o papel moderador do modelo de canal na relação entre os mecanismos de governança e os resultados da governança, o que faz com que os nosso resultados estejam relacionados coma realidade e sejam úteis ao mundo empresarial.

This thesis investigates the determinants of UK corporate cash holdings between 1980 and 2012. The global and long term phenomenon of corporate cash pilling has drawn significant attention from researchers. Similarly, this study aims at shedding light on the empirical relationship between cash holding and specific firm characteristics. Our preliminary research incorporates a comprehensive literature review. Towards this end, the relevant financial theory is presented and the previous empirical studies are highlighted. Afterwards, the expected results of our research are synthesized into a set of distinct hypotheses and tested with regression analysis. The empirical findings suggest that cash holdings are positively related to investment opportunity, as R&D and market to book ratio. Cash ratio is also positively related to industry cash flow volatility and negatively affected by cash flow, net working capital, capital expenditures, leverage, tax expenses, age and size. Regarding the development of the determinants of cash holdings, the study indicates that three major variables influenced cash holdings over the years of analysis. In particular, leverage, tax regime and capital expenditures significantly affect the corporate liquidity in UK market. Furthermore, the results suggest that cash holdings are mostly defined by trade off theory. Indeed, our findings offer stimulating insights on the factors that determine the firms’ cash holdings during the past three decades. These findings may be beneficial for financial managers, investors and consultants.
Στην παρούσα διατριβή εξετάζονται οι προσδιοριστικοί παράγοντες του δείκτη μετρητών σε επιχειρήσεις του Ηνωμένου Βασιλείου μεταξύ των ετών 1980 και 2012. Η διακράτηση μετρητών αποτελεί παγκόσμιο φαινόμενο και λαμβάνει της ανάλογης προσοχής από πληθώρα ερευνητών. Σε αυτή τη βάση, η μελέτη αυτή έχει ως στόχο να ρίξει φως σχετικά με την εμπειρική σχέση μεταξύ του δείκτη μετρητών και τα συγκεκριμένα χαρακτηριστικά που επηρεάζουν την ρευστότητα στις επιχειρήσεις διαχρονικά. Αρχικά η έρευνα ενσωματώνει μια βιβλιογραφική ανασκόπηση. Προς το σκοπό αυτό, οι σχετικές οικονομικές θεωρίες και οι προηγούμενες εμπειρικές μελέτες παρουσιάζονται. Στη συνέχεια, τα αναμενόμενα αποτελέσματα της έρευνας συντίθενται σε ένα σύνολο διακριτών υποθέσεων και δοκιμάζονται με ανάλυση παλινδρόμησης. Τα εμπειρικά ευρήματα υποδηλώνουν ότι ο δείκτης μετρητών σχετίζεται θετικά με τις επενδυτικές ευκαιρίες, τις δαπάνες Ε&Α και τον λόγο της αγοραίας προς τη λογιστική αξία των βιβλίων της επιχείρησης. Ο δείκτης μετρητών επίσης, σχετίζεται θετικά με την μεταβλητότητα των ταμειακών ροών του κλάδου και επηρεάζεται αρνητικά από τις ταμειακές ροές, το καθαρό κεφάλαιο κίνησης, τις κεφαλαιακές δαπάνες, την μόχλευση, τα φορολογικά έξοδα, την ηλικία και το μέγεθος των επιχειρήσεων. Όσον αφορά την εξέλιξη των προσδιοριστικών παραγόντων των ταμειακών ρευστών διαθεσίμων, η μελέτη δείχνει ότι τρεις είναι οι κύριες μεταβλητές που επηρεάζουν τη διακράτηση μετρητών κατά τη διάρκεια των χρόνων της ανάλυσης. Ειδικότερα, η μόχλευση, το φορολογικό καθεστώς και τις κεφαλαιακές δαπάνες επηρεάΖουν σημαντικά την απόφαση για εταιρική ρευστότητα στην αγορά του Ηνωμένου Βασιλείου. Επιπλέον, τα αποτελέσματα δείχνουν ότι η διακράτηση μετρητών ακολουθεί κυρίως την trade off θεωρία. Πράγματι, τα ευρήματά προσφέρουν χρήσιμες γνώσεις σχετικά με τους παράγοντες που καθορίζουν τη διακράτηση μετρητών των επιχειρήσεων κατά τη διάρκεια των τριών τελευταίων δεκαετιών. Τα ευρήματα αυτά μπορεί να είναι επωφελή για οικονομολόγους, επενδυτές και συμβούλους.

Packaging is an important element responsible for brand growth and one of the main rea-sons for producers to gain competitive advantages through technological innovation. In this re-gard, the aim of this work is to design a fully autonomous electronic system for a smart bottle packaging, being integrated in a European project named ROLL-OUT. The desired application for the smart bottle is to act as a fill-level sensor system in order to determine the liquid content level that exists inside an opaque bottle, so the consumer can exactly know the remaining quantity of the product inside. An in-house amorphous indium–gallium–zinc oxide thin-film transistor (a-IGZO TFT) model, previously developed, was used for circuit designing purposes. This model was based in an artificial neural network (ANN) equivalent circuit approach. Taking into account that only n-type oxide TFTs were used, plenty of electronic building-blocks have been designed: clock generator, non-overlapping phase generator, a capacitance-to-voltage converter and a comparator. As it was demonstrated by electrical simulations, it has been achieved good functionality for each block, having a final system with a power dissipation of 2.3 mW (VDD=10 V) not considering the clock generator. Four printed circuit boards (PCBs) have been also designed in order to help in the testing phase. Mask layouts were already designed and are currently in fabrication, foreseeing a suc-cessful circuit fabrication, and a major step towards the design and integration of complex trans-ducer systems using oxide TFTs technology.