This thesis aims at contributing to the characterization of the dynamics of bubbles in microfluidics through modeling and experiments. Two flow regimes encountered in microfluidics are studied, namely, the bubbly flow regime and the Taylor flow regime (or slug flow).In particular, the first part of this thesis focuses on the dynamics of a bubbly flow inside a horizontal, cylindrical microchannel in the presence of surfactants using numerical simulations. A numerical method allowing to simulate the transport of surfactants along a moving and deforming interface and the Marangoni stresses created by an in-homogeneous distribution of these surfactants on this interface is implemented in the Level set module of the research code. The simulations performed with this code regarding the dynamics of a bubbly flow give insights into the complexity of the coupling of the different phenomena controlling the dynamics of the studied system. Fo example it shows that the confinement imposed by the microchannel walls results in a significantly different distribution of surfactants on the bubble surface, when compared to a bubble rising in a liquid of infinite extent. Indeed, surfactants accumulate on specific locations on the bubble surface, and create local Marangoni stresses, that drastically influence the dynamics of the bubble. In some cases, the presence of surfactants can even cause the bubble to burst, a mechanism that is rationalized through a normal stress balance at the back of the bubble. The numerical method implemented in this thesis is also used for a practical problem, regarding the artisanal production of Mezcal, an alcoholic beverage from Mexico.The second part of the thesis deals with the dynamics of a Taylor flow regime, through experiments and analytical modeling. An experimental technique that allows to measure the thickness of the lubrication film forming between a pancake-like bubble and the microchannel wall is developed. The method requires only a single instantaneous bright-field image of a pancake-like bubble translating inside a microchannel. In addition to measuring the thickness of the lubrication film, the method also allows to measure the depth of a microchannel. Using the proposed method together with the measurment of the bubble velocity allows to infer the surface tension of the interface between the liquid and the gaz. In the last chapter of this thesis, the effect of buoyancy on the dynamics of a Taylor flow is quantified. Though often neglected in microfluidics, it is shown that buoyancy effects can have a significant impact on the thickness of the lubrication film and consequently on the dynamics of the Taylor flow. These effects are quantified using experiments and analytical modeling. This work was performed at Princeton University with Professor Howard A. Stone during an eight month stay. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

Orientador: Arlene Cristina Aguilar / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Física, 2012

The main concern of this thesis is to propose a new inverse identification procedure applied to metal forming and machining situations, which can provide an appropriate parameters set for any elastoplastic constitutive law following J_{2} plasticity and isotropic hardening, by evaluating the correlation between the experimental and numerical responses. Firstly the identification program has been developed, which combines the Levenberg-Marquardt algorithm and the Data processing methods to optimize the constitutive parameters. In terms of experimentation, dynamic compression and tensile tests have been conducted. The final deformed shape of specimens, which relies on a post-mortem analysis, has been selected as the observation quantity. As for the numerical simulation, the numerical models of the same experimental procedure have been built with the finite element software Abaqus/Explicit in order to provide numerical responses. A numerical algorithm has been proposed for the implementation of user defined elastoplastic constitutive laws in Abaqus/Explicit.

No description available.

Despite considerable research on the monetary policy rules, little is known about internal relation between policy rules targets. Research approach frequently consists in estimating parameters or identifying variables to make the rule operate accurately. The overall image that emerges from the literature is that there is no contradiction in attaining the targets once set properly. Dissertation switches attention to mutual feasibility of incorporated targets. To contribute to this strikingly overlooked fact hypothesis is tested. Analyzed are variances of inflation and output representing policy rule targets. Time regression processed throughout OLS technique, gap analysis and calculation of variances are applied as principal analytical tools. Examined are data for 14 countries. Countries are divided into two groups according to size of their economy: small economies (Austria, Belgium, Czech Republic, Hungary, Ireland, The Nederlands and Slovak Republic); large economies (Euro zone, France, Germany, Italy, Spain, Sweden and USA). Results of the analysis show that once monetary authority follows policy rule with multiple targets it faces restriction. Rather than achieving both targets at one time it must respect trade off between them. According to data for selected countries hypothesis is accepted. Variances of output consistently proved to be higher than variances of inflation. Whence it follows that authority need to solve constrained optimization problem. It needs to pick out combination of differently large variances contrary to wining with all reaching low levels.

The Taylor rule and its variants played a prominent role in the monetary policy discussion among theoreticians and practitioners for more almost two decades. The purpose of this thesis is to assess on the applicability of the simple instrument rules such as a classic Taylor's rule to the Czech economic environment which can be described as a small open economy with banking market specifically skewed by excess liquidity. The applicability is evaluated based on the variants of the Taylor rule and their effectiveness in describing the monetary policy of the central bank. The results of the models presented in this thesis are ambiguous. Traditional specification of the Taylor's rule is clearly unsuccessful in describing the behaviour of the Czech National Bank. However, if the models are altered to their historical variants containing only the information accessible at the time of decision making, their robustness and explanatory value increase significantly. Taking interest rate smoothing and exchange rate into consideration further improves the models. The policy behaviour of the Czech National Bank can be best described by the historical model with the one-year-ahead inflation prognosis, output gap, exchange rate and lagged target interest rate as explanatory variables. One of interesting results of this model is that the output gap does not play important role in the Czech National Bank decision making which is consistent with the opinions presented in the Czech National Bank Board Minutes.

Orientador: Denis Dalmazi / Coorientador: Álvaro de Souza Dutra / Banca: Julio Marny Hoff da Silva / Banca: Rafael Augusto Couceiro Corrêa / Resumo: Certos sistemas físicos podem ser descritos por uma classe de equações não-lineares. Essas equações descrevem pacotes de onda chamado de sólitons que tem aplicações em diversas áreas, por exemplo, Óptica, Cosmologia, Matéria Condensada e Física de Partículas. Alguns métodos foram desenvolvidos ao longo dos anos para encontrar as soluções dessas equações. Buscaremos essas soluções usando o que chamamos de Método Iterativo de Taylor (MIT), que fornece uma solução aproximada em polinômio de Taylor de forma distinta do que se tem na literatura. Usaremos o MIT para calcular soluções por aproximantes de Padé que são razões entre dois polinômios e fornecem soluções melhores que o polinômio de Taylor que o gerou. Inicialmente resolveremos a equação de um modelo de um campo denominado λφ4 . Em seguida resolveremos um modelo com dois campos escalares acoplados e encontraremos uma solução analítica aproximada em casos onde não existe solução analítica, explorando a diversidade das soluções do modelo. Usando essa abordagem por aproximantes de Padé veremos que há algumas vantagens em relação a outros métodos / Abstract: Certain physical systems can be described by a class of non-linear differential equations. Those equations describe wave packets called solitons which have applications in several areas, for example, Optics, Cosmology, Condensed Matter, and Particle Physics. Some methods have been developed over the years to find solutions to these equations. We will look for those solutions using what we call the Taylor Iterative Method (TIM), which provides an approximate solution in terms of a Taylor's polynomial in a unusual way, regarding the present literature. We will use TIM to calculate solutions by Padé approximants, which are ratios between two polynomials and provide better solutions than the Taylor polynomial itself. We first solve the field equation of a model called λφ4 . Then we will solve a model with two coupled scalar fields and find an approximate analytic solution in cases where there is no known analytical solution, exploring the diversity of the solutions of the model. We will see that there are some advantages in using the Padè approximants as compared to other methods / Mestre

This master thesis is focused on interpreting theological motives in the social theory of P. L. Berger and Ch. Taylor, particularly in relation to their interpretation of the concepts of secularization and secularity. The first objective of the thesis is to demonstrate whether these partial sociological concepts can be read as theologically conditioned. Consequently, to elucidate how the dependence of these concepts on their theological origins influences the explanation of the pertinence of Christianity in the contemporary world. The second aim of this thesis is to testify the inner connection between the ideas of both authors; in order to explain how and for what reason the concepts of secularization and secularity acquire the same or different expressions. This thesis is organized into four sections, the first section defines the framework of the secularization debate in which the topic of this work operates. The second and third sections provide an analysis of Berger and Taylor's sociological approach. The last section compares the concepts that prove to be essential for the interpretation of secularization and secularity in Berger and Taylor.

Background: Measures of central tendency are one of the foundational concepts of statistics, with the most commonly used measures being mean, median, and mode. While these are all very simple to calculate when data conform to a unimodal symmetric distribution, either discrete or continuous, measures of central tendency are more challenging to calculate for data distributed asymmetrically. There is a gap in the current statistical literature on computing median and mode for most skewed unimodal continuous distributions. For example, for a standardized normal distribution, mean, median, and mode are all equal to 0. The mean, median, and mode are all equal to each other. For a more general normal distribution, the mode and median are still equal to the mean. Unfortunately, the mean is highly affected by extreme values. If the distribution is skewed either positively or negatively, the mean is pulled in the direction of the skew; however, the median and mode are more robust statistics and are not pulled as far as the mean. The traditional response is to provide an estimate of the median and mode as current methodological approaches are limited in determining their exact value once the mean is pulled away. Methods: The purpose of this study is to test a new statistical method, utilizing the first order and second order partial derivatives in Taylor series expansion, for approximating the median and mode of skewed unimodal continuous distributions. Specifically, to compute the approximated mode, the first order derivatives of the sum of the first three terms in the Taylor series expansion is set to zero and then the equation is solved to find the unknown. To compute the approximated median, the integration from negative infinity to the median is set to be one half and then the equation is solved for the median. Finally, to evaluate the accuracy of our derived formulae for computing the mode and median of the skewed unimodal continuous distributions, simulation study will be conducted with respect to skew normal distributions, skew t-distributions, skew exponential distributions, and others, with various parameters. Conclusions: The potential of this study may have a great impact on the advancement of current central tendency measurement, the gold standard used in public health and social science research. The study may answer an important question concerning the precision of median and mode estimates for skewed unimodal continuous distributions of data. If this method proves to be an accurate approximation of the median and mode, then it should become the method of choice when measures of central tendency are required.

Mary Szybist's 2013 collection, Incarnadine, uses the Annunciation as a foundational narrative through which to examine the implications of faith and having a relationship with God. Transforming this pivotal Biblical event through metaphor, intertextuality, and different points of view, Szybist showcases what Charles Taylor terms "fragilization" of faith, or the contestable and dubious position of believing among plurality of belief and nonbelief. By repeatedly shifting the framing of the Annunciation, Szybist creates several different visions of who God is. Rather than reinterpreting the Annunciation with a new dictum on exactly who God is and what it means to believe in Him, she plays with her own definition of God, allowing readers to do the same, and thus work through "fragilization" and find a faith that fits them.