Ce travail décrit le développement d’un outil de simulation du transport réactif, nommé SpeCTr (Spéciation Cinétique Transport), intégrant le fractionnement isotopique. Ce modèle est obtenu à travers le couplage d’un module décrivant le transport et d’un module décrivant les principales réactions chimiques (approche de séparation d’opérateur). Une grande partie du travail est dédiée à l’amélioration des algorithmes du module décrivant les réactions chimiques pour la résolution des équations de l’équilibre thermodynamique (méthode de Newton Raphson modifiée à travers les techniques du scaling et des Fractions Continues Positives) et du mélange de réactions cinétiques et à l’équilibre (étude sur la formulation et résolution des systèmes d’équations différentielles et différentielles-algébriques). L’outil est validé à travers la résolution de plusieurs tests (batch et transport réactif) et appliqué pour la simulation d’expériences de laboratoire en 1D, 2D et 3D portant sur la dissolution des cristaux de calcite dans une colonne de milieu poreux / The work describes the development of a reactive transport code named SpeCTr (Spéciation Cinétique Transport in French). The code, able to describe isotopic fractionation, is obtained through the coupling of a transport module and a reaction module that describes the main chemical reactions (operator splitting approach). A consistent portion of the work is dedicated to the improvement of the numerical methods employed in the reaction module for solving thermodynamic equilibrium (Newton Raphson method modified with scaling and Positive Continuous Fractions) and mixed equilibrium and kinetic reactions (formulation and solution of systems of differential and differential-algebraic equations). The code was verified through the solution of different benchmarks (batch and reactive transport simulations) and applied to perform 1D, 2D and 3D simulations of laboratory experiments dedicated to calcite crystals dissolution in a column of porous medium.

Orientador: Salatiér Buzetti / Banca: Marco Eustáquio de Sá / Banca: Orivaldo Arf / Banca: Rita de Cássia Félix Alvarez / Banca: Rogério Peres Soratto / Resumo: A cultura do milho encontra-se entre as de maior potencial de produtividade de grãos, embora no Brasil alguns fatores não permitam que seja expressa a capacidade máxima de produtividade da cultura, que está muito aquém da produtividade média. Para a obtenção de altas produtividades economicamente viáveis, a nutrição mineral adequada é um dos fatores essenciais e o nitrogênio é o nutriente que, via de regra, proporciona os maiores efeitos. O objetivo do trabalho foi comparar os efeitos de diferentes fontes nitrogenadas: sulfonitrato de amônio (SNA), sulfato de amônio (S.A.) e uréia (U), na semeadura e em cobertura, nas características agronômicas do milho, conduzido em solo da região de Selvíria/MS, sob irrigação por aspersão. O trabalho foi desenvolvido na fazenda experimental da Faculdade de Engenharia de Ilha Solteira, UNESP, Selvíria-MS, em um Latossolo Vermelho distrófico, no ano agrícola 2004/05. O delineamento experimental utilizado foi blocos casualizados com quatro repetições, dispostos em esquema fatorial 3x5, sendo: três fontes de nitrogênio (SNA, S.A. e U) aplicadas na semeadura e em cobertura, no estádio de 8 folhas completamente desdobradas, em 5 modos de aplicação (0 + 120; 30 + 90; 60 + 60; 90 + 30 e 120 + 0 kg de N ha-1). A aplicação da fonte nitrogenada sulfonitrato de amônio e o modo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The corn crop has high productivity potential, although in Brazil it is below of expectation. The mineral nutrition, mainly to concern to nitrogen, is essential to obtain high productivity and feasible economically. The work was conducted at Experimental Station of Universidade Estadual Paulista - UNESP - Ilha Solteira Campus, UNESP/FEIS, located in Selvíria-MS, in a Red dystrophic Latosol (Oxisol), in the agricultural year 2004/05. The objective of this study was to evaluate sources and times of nitrogen application. A randomized blocks design with four repetitions, in a factorial scheme 3x5, was used. Three sources of nitrogen (Sulphonitrate of ammonium, Ammonium sulfate and Urea) applied at sowing and/or covering at stadium of 8 leaves completely unfolded, in 5 combinations (0 + 120; 30 + 90; 60 + 60; 90 + 30 and 120 + 0 kg of N ha-1) constituted the treatments. The nitrogen sources as Sulphonitrate of ammonium and the combination of 60 kg ha-1 at sowing and at 8 leaf stadium provided the larger N leaf content. The grain yield was higher in the treatment that received 30 kg of N ha-1 at sowing + 90 kg of N ha-1 at 8 leaf stadium, and that treatment where N was only supplied at 8 leaf stadium (0 + 120 kg of N ha-1), it provided grain yield of 7,745 kg ha-1 and 7,667 kg ha- 1, respectively... (Complete abstract, click electronic access below) / Doutor

Argumentation and reasoning have been an area of research in such disciplines as philosophy, logic and artificial intelligence for quite some time now. In the area of AI, knowledge needed for reasoning can be represented using various kinds of representation systems. The natural problem posed by this fact is that of possible incompatibility between heterogeneous systems as far as communication between them is concerned. This imposes a limitation on the possibility of extending smaller knowledge bases to larger ones. In order to facilitate a common platform for exchange across the systems unified formalisms for the different approaches to knowledge representation are required. This was the motivation for Dung [11] to propose in his 1995 paper an approach that later came to be known as an abstract argumentation framework. Roughly speaking, Dung's arguments are abstract entities which are related to each other by the means of conflicts between them. An intuitive graphical representation of Dung style framework is a graph whose nodes stand for arguments and whose edges stand for conflicts. A framework postulated this way is on one hand too general to be used on its own, but on the other hand it is general enough as to allow for varied extensions increasing its expressiveness, which indeed have been proposed. They include value-based argumentation frameworks by Bench-Capon et al. [6], preference-based argumentation frameworks by Amgoud and Cayrol [1] and bipolar argumentation frameworks by Brewka and Woltran [7], to name a few. The present thesis is concerned with yet another variation of Dung's framework: the concept of splitting. It was developed by Baumann [4] with one of the underlying purposes being that the computation time in frameworks which have been split into two parts and then computed separately may show some improvement in comparison to their variant without splitting. It was one of the main tasks of my work to develop an efficient algorithm for the splitting operation based on the theoretical framework given in [4]. On the other hand I hoped to confirm the expectation that splitting can indeed make a computation perform better.

The dissertation consists of two parts. In the first part approximate methods for multidimensional weakly singular integral operators with operator-valued kernels are investigated. Convergence results and error estimates are given. There is considered an application of these methods to solving radiation transfer problems. Numerical results are presented, too. In the second part we consider a polynomial collocation method for the numerical solution of a singular integral equation over the interval. More precisely, the operator of our integral equation is supposed to be of the form \ $aI + b \mu^{-1} S \mu I $\ with \ $S$\ the Cauchy singular integral operator, with piecewise continuous coefficients \ $a$\ and \ $b,$\ and with a Jacobi weight \ $\mu.$\ To the equation we apply a collocation method, where the collocation points are the Chebyshev nodes of the first kind and where the trial space is the space of polynomials multiplied by another Jacobi weight. For the stability and convergence of this collocation method in weighted \ $L^2$\ spaces, we derive necessary and sufficient conditions. Moreover, the extension of these results to an algebra generated by the sequences of the collocation method applied to the mentioned singular integral operators is discussed and the behaviour of the singular values of the discretized operators is investigated. / Die Dissertation beschäftigt sich insgesamt mit der numerischen Analysis singulärer Integralgleichungen, besteht aber aus zwei voneinander unabhängigen Teilen. Der este Teil behandelt Diskretisierungsverfahren für mehrdimensionale schwach singuläre Integralgleichungen mit operatorwertigen Kernen. Darüber hinaus wird hier die Anwendung dieser allgemeinen Resultate auf ein Strahlungstransportproblem diskutiert, und numerische Ergebnisse werden präsentiert. Im zweiten Teil betrachten wir ein Kollokationsverfahren zur numerischen Lösung Cauchyscher singulärer Integralgleichungen auf Intervallen. Der Operator der Integralgleichung hat die Form \ $aI + b \mu^{-1} S \mu I $\ mit dem Cauchyschen singulären Integraloperator \ $S,$\ mit stückweise stetigen Koeffizienten \ $a$\ und \ $b,$\ und mit einem klassischen Jacobigewicht \ $\mu.$\ Als Kollokationspunkte dienen die Nullstellen des n-ten Tschebyscheff-Polynoms erster Art und Ansatzfunktionen sind ein in einem geeigneten Hilbertraum orthonormales System gewichteter Tschebyscheff-Polynome zweiter Art. Wir erhalten notwendige und hinreichende Bedingungen für die Stabilität und Konvergenz dieses Kollokationsverfahrens. Außerdem wird das Stabilitätskriterium auf alle Folgen aus der durch die Folgen des Kollokationsverfahrens erzeugten Algebra erweitert. Diese Resultate liefern uns Aussagen über das asymptotische Verhalten der Singulärwerte der Folge der diskreten Operatoren.

The electrocatalytic water decomposition has been investigated in this thesis by means of its two half standard reactions: the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). These reactions occur in different locations in a typical electrochemical cell: the anode and the cathode, respectively. Motivated by the lack of understanding about the reaction mechanisms occurring at the anodes and cathodes, we have proposed first: novel representations of typical TiO2 surfaces, based on small cluster systems, which can be used for a quick and more detailed assessment of the OER activities at modified TiO2 surfaces, and secondly we investigated the HER in two sets of model surfaces which represent recently synthesized materials, based on Mo2C and graphene with promising activities toward the HER. We have employed Density Functional Theory (DFT) based methods within both localized and extended basis sets, as implemented in GAMESS and VASP packages, respectively, to examine the structural, electronic and vibrational properties of the proposed models. We propose new reaction mechanisms for the OER on a number of molecular representations of TiO2 electrodes. For each reaction pathway, the free energy profile is computed, at different biases, from the DFT energies, the entropic and the zero-point energy contributions. The mechanisms explored in this thesis are found to be energetically more feasible than alternative reaction pathways considered in previous theoretical works based on molecular representations of the TiO2 surfaces. The representation of the surface of specific, commonly occurring, titanium dioxide crystals (e.g., rutile and anatase) within the small cluster approximation is able to reproduce qualitatively the rutile (110) outperforming of the anatase (001) surface. We subsequently investigate the influence of doping TiO2 surfaces with transition metals (TMs) on the performance of TiO2 -based electrodes for the water splitting electrochemical reaction. Two cluster models of the TM-doped active sites which resemble both the TiO2 anatase (001) and rutile (110) surfaces, respectively, are considered for the evaluation of the water decomposition reaction when a Ti is replaced by a TM atom. A set of TMs spanning from Vanadium to Nickel is considered. The late TMs explored here: Fe, Co and Ni are found to reproduce the observed experimental trends for the overpotentials in TiO2-doped electrodes. In the case of Cr and Mn, the present study predicts an enhancement of the OER activity for the anatase-like clusters while a reduction of this activity is found for the rutile-like ones. The vanadium-doped structures do not show relevant influence in the OER activity compared to pure TiO2-based cluster models. The last part of this work is devoted to the theoretical study of the HER on recently found materials based on the synergistic combination of molybdenum carbide and graphene layers. We propose two major structural models to describe the HER mechanism within the framework of DFT: Mo2C-based clusters adsorbed on carbon nanosheets and the Mo2C (001) surface covered by pure and nitrogen-doped graphene layers. The former system evaluates the influence of Mo2C nanoparticles adsorbed on carbon nanosheets towards the HER. The second one is employed to gain insight about the high HER activity observed in molybdenum carbide anchored on nitrogen-doped porous carbon nanosheets (Mo2C@2D-NPC), recently synthesized. The H-adsorption free energy has been used as a principal descriptor to asses the HER activity at the proposed model active sites. It resembles the value for the best state of the art catalyst for the HER (i.e., platinum at carbon substrate Pt@C) in some of the proposed structural models. Furthermore, a pH-correction is added within a simplified model, to the H-adsorption free energy barrier in every proposed structure. The pH dependence of the H-adsorption free energy barriers allows the assessment of the HER at acidic and alkaline conditions simultaneously. An overall agreement with experimental results is found and further predictions, promoting the development of better HER catalysts, have been done.

To achieve sustainable production of H2 fuel through water splitting, low-cost electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are required to replace Pt and IrO2 catalysts. Here, for the first time, we present the interface engineering of novel MoS2/Ni3S2 heterostructures, in which abundant interfaces are formed. For OER, such MoS2/Ni3S2 heterostructures show an extremely low overpotential of ~218 mV at 10 mA cm-2, which is superior to that of the state-of-the-art OER electrocatalysts. Using MoS2/Ni3S2 heterostructures as bifunctional electrocatalysts, an alkali electrolyser delivers a current density of 10 mA cm-2 at a very low cell voltage of ~1.56 V. In combination with density function theory (DFT) calculations, this study demonstrates that the constructed interfaces synergistically favor the chemisorption of hydrogen and oxygencontaining intermediates, thus accelerating the overall electrochemical water splitting.

In this thesis electromagnetic wave propagation is investigated in an indoor environment. The indoor environment is a furnished office building with corridors, corners and rooms. Particularly, there is an atrium through the building in the center. For the study there were measurements available from real building in the 2.1 GHz frequency band. One objective is to design a propagation model that should be simple but reflect the trend of the propagation measurements. Furthermore, a system performance evaluation is carried out based on the implemented model. The proposed 3D model is a combination of the Free Space Path Loss model, the Keenan-Motley model and the recursive diffraction model. The channel predictions from the 2D Keenan-Motley algorithm are quite different from the measurements. Therefore, the 3D Keenan-Motley algorithm is designed to depict the atrium effect and speed up the simulation at the same time. Besides a buttery radiation diagram is created to mimic Kathrein 80010709 antenna installed in the building. Finally, a diffracted path is added to improve the received signal strength for the users around the atrium areas. With all the above procedures, the final results from the model are in good quantitative agreement with the measurement data. With the implemented propagation model, a further analysis of the system performance on the Distributed Antenna System (DAS) is performed. A comparison for the system capacity between the closed building and the atrium building is conducted, showing that the former one benefits more when the number of the cells increases. The reason is the atrium cells suffer severe interference from neighbor cells during high traffic demand scenarios. Then some further cell configurations show that the number of the cells, the geometry performance and the balance of the user fraction should be considered to improve the system capacity.

[pt] Esta tese consiste num percurso de estudo sobre a obra de Sándor Ferenczi, tendo como ferramenta de leitura a concepção de jogo de linguagem formulada por Wittgenstein, e a dimensão ética apresenta-se como elemento norteador para as questões propostas. Os jogos de linguagem que permeiam as formulações ferenczianas, tanto no campo teórico quanto no clínico, nos permitem captar as transformações ocorridas ao longo do tempo. Percebemos como o foco inicial de Ferenczi foi contribuir para a técnica clássica e, paulatinamente, modificou-se e abriu espaço para um aspecto mais experimental, acarretando na criação de um vocabulário próprio e singular ao viabilizar percepções inovadoras acerca da subjetividade. / [en] This thesis is a course of study on the work of Sándor Ferenczi, having as reading tool the conception of language game formulated by Wittgenstein, and the ethical dimension presents itself as guiding element for the proposed questions. The language games that permeate Ferenczian formulations, both in the theoretical and clinical fields, allow us to capture the transformations occurred over time. We perceive how Ferenczi s primordial focus on contributing to the classical technique gradually changed and opened space for a more experimental aspect, resulting in the creation of a particular and unique vocabulary by enabling innovative perceptions on subjectivity.

<p>In this work, we study a class of Markovian information theoretic optimization problems motivated by the recent interests in incorporating mutual information as performance metrics which gives evident success in representation learning, feature extraction and clustering problems. In particular, we focus on the information bottleneck (IB) and privacy funnel (PF) methods and their recent multi-view, multi-source generalizations that gain attention because the performance significantly improved with multi-view, multi-source data. Nonetheless, the generalized problems challenge existing IB and PF solves in terms of the complexity and their abilities to tackle large-scale data. </p> <p>To address this, we study both the IB and PF under a unified framework and propose solving it through splitting methods, including renowned algorithms such as alternating directional method of multiplier (ADMM), Peaceman-Rachford splitting (PRS) and Douglas-Rachford splitting (DRS) as special cases. Our convergence analysis and the locally linear rate of convergence results give rise to new splitting method based IB and PF solvers that can be easily generalized to multi-view IB, multi-source PF. We implement the proposed methods with gradient descent and empirically evaluate the new solvers in both synthetic and real-world datasets. Our numerical results demonstrate improved performance over the state-of-the-art approach with significant reduction in complexity. Furthermore, we consider the practical scenario where there is distribution mismatch between training and testing data generating processes under a known bounded divergence constraint. In analyzing the generalization error, we develop new techniques inspired by the input-output mutual information approach and tighten the existing generalization error bounds.</p>

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