<p>A computer model based on minimization of the free energy, capable to predict contact angles and spreading transitions between Wenzel and Cassie mode for drops placed on surfaces with different topography were implemented in matlab. Simulations were compared with experiments documented in the literature. These showed that reported transitions between Cassie and Wenzel mode can be explained by minimization of the free energy. In this report, a study on the possibility of constructing water repellent paper surfaces with a combination of treatment with octadecyltrichlorosilane and topography changes, is included.</p>

A computer model based on minimization of the free energy, capable to predict contact angles and spreading transitions between Wenzel and Cassie mode for drops placed on surfaces with different topography were implemented in matlab. Simulations were compared with experiments documented in the literature. These showed that reported transitions between Cassie and Wenzel mode can be explained by minimization of the free energy. In this report, a study on the possibility of constructing water repellent paper surfaces with a combination of treatment with octadecyltrichlorosilane and topography changes, is included.

An introduction is given to the background theory and scientific literature of the major subject areas of interest in this thesis, namely the chemistry of free radical and anionic polymerisation, molecular weight control in each type of polymerisation, polymerisation reactors, computer simulation of polymerisation processes and polymer characterisation by gel permeation chromatography. A novel computer model has been devised, based on the analysis of the polymerisation process in terms of the reaction extent of each reactant and the use of generation functions to describe the concentration of living and dead polymeric species, for the free radical, solution polymerisation of methylmethacrylate in a CSTR. Both heat and mass balance expressions have been described. Conversion, Mn and Mw were monitored. To test the model a reactor was designed and constructed. A detailed description of the reactor and the experimental conditions used for the validation of the model are given. The results of these studies are presented and excellent agreement is shown between model predictions and experiments up to 30% conversion for Mn w and % conversion. A similar study is described for the anionic polymerisation of styrene in tetrahydrofuran as solvent, in a CSTR. In this work the computer model becomes 'stiff' when realistic rate constants are introduced in the kinetic expressions. Experimental difficulties were encountered in obtaining reproducible results in the anionic work. A new approach of using 'scavengers' as protecting agents for the living chains is described. A scavenger was successfully employed in the preparation of block copolymers using a tubular reactor. Block copolymerisation, in addition to providing a means of checking the number of the 'living' chains inside the reactor, is of interest in its own right. All the experimental findings are discussed in relation to the currently accepted views found in the scientific literature.

This research work is focused on understanding the effects of inhomogeneity on traffic flow by theoretical analysis and computer simulations. Traffic has been observed at almost all levels of natural and manmade systems (e.g., from microscopic protein motors to macroscopic objects like cars). For these various traffic, basic and emer- gent phenomena, modelling methods, theoretical analysis and physical meanings are normally concerned. Inhomogeneity like bottlenecks may cause traffic congestions or motor protein crowding. The crowded protein motors may lead to some human diseases. The congested traffic patterns have not been understood well so far. The modelling method in this research is based on totally asymmetric simple exclusion process (TASEP). The following TASEP models are developed: TASEP with single inhomogeneity, TASEP with zoned inhomogeneity, TASEP with junction, TASEP with site sharing and different boundary conditions. These models are motivated by vehicular traffic, pedestrian trafficc, ant traffic, protein motor traffic and/or Internet traffic. Theoretical solutions for the proposed models are obtained and verified by Monte Carlo simulations. These theoretical results can be used as a base for further developments. The emergent properties such as phase transitions, phase separations and spontaneous symmetry breaking are observed and discussed. This study has contributed to a deeper understanding of generic traffic dynamics, particularly, in the presence of inhomogeneity, and has important implications for explanation or guidance of future traffic studies.

The thesis deals with a computer modelling by means of the commercial software COMSOL Multiphysics. The thesis is structured into three topical sections. The first part is dedicated to the programme characteristics and its development. In the second part the brief characteristics of working with the programme COMSOL Multiphysics is presented which should make the user´s first steps in working with software easier. The last part of thesis shows the specific demonstration of the created multiple physics task taken from the field of plasma physics. This task is solved by means of continuous simulation of a computer modelling based on the drift-diffusion approximation of low temperature plasma. The proposal of the paper for the proceedings of the conference ,,Technical Computing Prague 2012" is also a part of this thesis.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Foi implementado, na linguagem Visual Basic 6, um programa computacional para a anÃlise do Golpe de ArÃete em adutoras, utilizando-se do MÃtodo das CaracterÃsticas e das equaÃÃes caracterÃsticas de equipamentos normalmente encontrados nos sistemas hidrÃulicos. Procurou-se desenvolver um aplicativo que possibilite ao usuÃrio visualizar o comportamento das ondas de sobrepressÃo e subpressÃo decorrentes do fenÃmeno transitÃrio, alÃm de verificar a influÃncia da chaminà de equilÃbrio e do tanque de alimentaÃÃo unidirecional (TAU) como dispositivos de alÃvio do golpe de arÃete. Aplicou-se o modelo computacional na anÃlise dos transientes hidrÃulicos gerados pelo desligamento do conjunto moto-bomba, e na avaliaÃÃo da eficiÃncia da chaminà de equilÃbrio e do tanque de alimentaÃÃo unidirecional como mecanismos de atenuaÃÃo dos picos de pressÃo. A validaÃÃo do modelo se deu atravÃs da comparaÃÃo dos resultados das simulaÃÃes com os dados obtidos nos testes realizados utilizando-se o CTran, software desenvolvido pela FundaÃÃo Centro TecnolÃgico de HidrÃulica da Escola PolitÃcnica da Universidade de SÃo Paulo. De acordo com a anÃlise estatÃstica, o programa desenvolvido apresentou resultados bastante satisfatÃrios na anÃlise do golpe de arÃete, possuindo uma interface de fÃcil utilizaÃÃo e visualizaÃÃo dos resultados, fato de fundamental importÃncia para que projetistas e estudantes compreendam o comportamento do fenÃmeno. / The main goal of this research is the development of the computer code designed to model the water hammer problem which occurs in water pipes. It was used the method of characteristics to numerically solve the differential equations which control the problem. The software developed allows the user to visualize the behavior oh the over and under pressure waves resulting from the occurrence of the transient problem. Other features of the developed software includes the possibility of analyzing the introduction of mechanisms to decrease the effects of the water hammer problem such as orifice tanks, one-way tanks, closed tanks and relief valves. The developed model was applied and validated to water conducts which was previously been analyzed by the software CTran, developed by the âEscola PolitÃcnica de Universidade de SÃo Pauloâ. The results were very satisfactory

La reconnaissance de la langue des signes française (LSF) comme une langue à part entière en 2005 a créé un besoin important de développement d’outils informatiques pour rendre l’information accessible au public sourd. Dans cette perspective, cette thèse a pour cadre la modélisation linguistique pour un système de génération de la LSF. Nous présentons dans un premier temps les différentes approches linguistiques ayant pour but la description linguistique des langues des signes (LS). Nous présentons ensuite les travaux effectués en informatique pour les modéliser.Dans un deuxième temps, nous proposons une approche permettant de prendre en compte les caractéristiques linguistiques propres au LS tout en respectant les contraintes d’un processus de formalisation. En étudiant des liens entre des fonctions sémantiques et leurs formes observées dans les corpus LSF, nous avons identifié plusieurs règles de production. Nous présentons finalement le fonctionnement des règles comme étant un système susceptible de modéliser un énoncé entier en LSF. / The recognition of French Sign Language (LSF) as a natural language in 2005 has created an important need for the development of tools to make information accessible to the deaf public. With this prospect, this thesis aims at linguistic modeling for a system of generation of LSF. We first present the different linguistic approaches aimed at describing the sign language (SL). We then present the models proposed in computer science. In a second step, we propose an approach allowing to take into account the linguistic properties of the SL while respecting the constraints of a formalisation process.By studying the links between semantic functions and their observed forms in LSF Corpora, we have identified several production rules. We finally present the rule functioning as a system capable of modeling an entire utterance in LSF.

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