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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
801

A papaína no tratamento da periodontite crônica / Papain in the treatment of chronic periodontitis

Luiz Eduardo Monteiro Dias da Rocha 31 March 2010 (has links)
A raspagem subgengival e o alisamento radicular constituem o "padrão ouro" e o tratamento de eleição para a periodontite; porém, é um procedimento difícil de ser executado, que requer um intenso treinamento e que pode expor a dentina, causando hipersensibilidade dentinária pela remoção excessiva de cemento, ou produzir defeitos, como sulcos e ranhuras, além de deixar cálculo residual e não conseguir atingir toda as superfície radicular. Recentemente, um gel a base de papaína e cloramina foi introduzido no mercado (Papacárie), utilizado no tratamento da remoção de dentina cariada. Este gel poderia auxiliar na remoção do cálculo subgengival com menor desgaste do cemento. O objetivo deste trabalho foi comparar a eficácia e analisar a superfície radicular na utilização de um gel à base de papaína e cloramina, associado ao alisamento radicular, na região subgengival. Após receberem instruções de higiene oral, raspagem supragengival e polimento coronário, 18 pacientes com periodontite crônica, 6 mulheres e 12 homens, com idade média de 51 anos (8) foram tratados num modelo de boca dividida. O tratamento-teste foi constituído pela aplicação do gel na área subgengival por 1 min., seguida pelo alisamento radicular; o tratamento-controle foi constituído pela raspagem subgengival e alisamento radiculares. A terapia foi executada por 3 operadoras e os exames inicial, de 28 dias e 3 meses, foram realizados por um único examinador. Quatro dentes nunca tratados de dois outros pacientes (2 incisivos centrais inferiores e 2 premolares), com indicação para extração, foram submetidos ao tratamento teste e controle e, após a exodontia, analisados em microscopia eletrônica de varredura (MEV). Ao longo dos 3 meses, os resultados demonstraram significativa melhora nos parâmetros clínicos: sangramento à sondagem, profundidade de bolsa e ganho de inserção, tanto no lado-teste, como no lado-controle, principalmente aos 28 dias; mas não foi observada significância estatística quando ambas as formas de terapia foram comparadas. O índice de placa médio permaneceu alto ao longo do estudo. A análise do MEV demonstrou que o tratamento-teste deixou uma maior quantidade de cálculo residual sobre a superfície radicular; porém, áreas livres de cálculo também foram observadas. No tratamento-controle, verificaram-se regiões mais profundas não atingidas pelas curetas, áreas livres de cálculo e um sulco produzido pela cureta. Concluiu-se que tanto o tratamento-teste, como o controle, foram eficazes no tratamento da periodontite crônica nos 3 meses observados. / Although subgingival scaling and root planing are the gold standard for elective treatment of periodontitis, they are difficult procedures to perform. As well as requiring intensive training, they can expose the dentin, causing dentin hypersensitivity by excessive removal of cement, or produce defects such as ridges and grooves, leaving residual calculus, whilst the whole root surface cannot be reached. A papain- and chloramine-based gel (Papacárie) has recently been introduced to remove carious dentin. This gel may help in the removal of subgingival calculus with reduced consumption of cement. The objective of this study was to compare the effectiveness of a papain- and chloramine-based gel and analyze the root surface in the region associated with subgingival root planing. After receiving oral hygiene instructions, supragingival scaling and coronary polishing, 18 chronic periodontitis patients (6 women and 12 men with a mean age of 51 years 8) were treated using a split-mouth model. The test treatment was established by applying the gel to the subgingival area for 1 minute, followed by root planing; whilst the control treatment was established by subgingival scaling and root planing. The therapy was performed by 3 operators, examinations initially and after 28 days and 3 months being performed by a single examiner. Four previously untreated teeth (2 lower central incisors and 2 premolars) with indication for extraction in two other patients were treated as test and control and analyzed by scanning electron microscopy (SEM) following extraction. Although over the 3 months the results showed marked improvement in clinical parameters: bleeding on probing, pocket depth and attachment gain on both test and control sides, especially after 28 days; the difference between the two forms of therapy was not found to be statistically significant. The mean plaque index remained high throughout the study. The SEM analysis showed that the test treatment left a larger amount of residual calculus on the root surface, but areas free of calculus were also observed. In the control treatment, deeper areas unaffected by the scaling and root planing, areas free of calculus and a groove produced by the curette were found. It was concluded that both test and control treatments were effective in the treatment of chronic periodontitis observed over 3 months.
802

Lattice structures with pivoted beams : Homogenization and nonlinear elasticity results / Structures en treillis avec poutres pivotantes : homogénéisation et résultats d'élasticité non-linéaire

Della Corte, Alessandro 15 December 2017 (has links)
Cette thèse est consacrée à la modélisation des structures fibreuses avec des milieuxcontinus généralisés. Dans l’Introduction, l'état de l'art concernant les milieuxcontinus généralisée et applications aux structures fibreuses sont décrits et lesproblèmes ouverts pertinents sont mis en évidence. Dans le Chapitre 1 et 2, uneprocédure d'homogénéisation rigoureuse basée sur des arguments de Gammaconvergenceest appliquée à une structure en treillis et à un model de poutrediscrétisé. Dans le Chapitre 3, un traitement variationnel est utilisé pour formuler unapproche favorable du point de vue numérique. Dans le Chapitre 4 sont discutées lesrésultats expérimentaux concernant le comportement de la structure dans différentstypes de déformation. Cela à motivé les études effectuées dans le Chapitre 5, ou lesMéthodes directes de calcul des variations sont appliquées à poutres d’Euler engrandes déformations. / This thesis focuses on the mathematical modeling of fibrous structures having somepeculiar properties (high strength-to-weight ratio and very good toughness infracture), whose mechanical behavior escapes from standard Cauchy elasticity. Inparticular, it addresses cases in which the presence of a microstructure, consisting ofregularly spaced pivoted beams, entails effects that are well described by generalizedcontinuum models, i.e. models in which the deformation energy density depends notonly on the gradient of the placement but also on the second (and possibly higher)gradients of it. In the Introduction, the state of the art concerning generalizedcontinua and their applications for the description of fibrous structures is describedand some relevant open problems are highlighted. In Chapter 1 and 2 a rigoroushomogenization procedure based on Gamma-convergence arguments is performedfor a lattice (truss-like) structure and for a discrete 1D system (Hencky-type beammodel). In Chapter 3, a variational treatment is employed to formulate acomputationally convenient approach. In Chapter 4 some experimental resultsconcerning the behavior of the structure in various kinds of deformation arediscussed. This motivated the investigation performed in Chapter 5, in which DirectMethods of Calculus of Variations are applied to Euler beams in large deformationsunder distributed load.
803

Réalisabilité classique : nouveaux outils et applications / Classical realizability : new tools and applications

Geoffroy, Guillaume 29 March 2019 (has links)
La réalisabilité classique de Jean-Louis Krivine associe à chaque modèle de calcul et chaque modèle de la théorie des ensembles un nouveau modèle de la théorie des ensembles, appelé modèle de réalisabilité, d'une façon similaire au forcing. Chaque modèle de réalisabilité est muni d’une algèbre de Boole caractéristique $\gimel 2$ (gimel 2), dont la structure donne des informations sur les propriétés du modèle de réalisabilité. En particulier, les modèles de forcing correspondent au cas où $\gimel 2$ est l'algèbre de Boole à deux éléments.Ce travail présente de nouveaux outils pour manipuler les modèles de réalisabilité et donne de nouveaux résultats obtenus en les exploitant. L'un d'entre eux est qu'au premier ordre, la théorie des algèbres de Boole à au moins deux éléments est complète pour $\gimel 2$, au sens où $\gimel 2$ eut être rendue élémentairement équivalente à n'importe quelle algèbre de Boole. Deux autres résultats montrent que $\gimel 2$ peut être utilisée pour étudier les modèles dénotationnels de langage de programmation (chacun part d'un modèle dénotationnel et classifie ses degrés de parallélisme à l'aide de $\gimel 2$). Un autre résultat montre que la technique de Jean-Louis Krivine pour réaliser l'axiome des choix dépendants à partir de l'instruction quote peut se généraliser à des formes plus fortes de choix. Enfin, un dernier résultat, obtenu en collaboration avec Laura Fontanella, accompagne le précédent en adaptant la condition d'antichaîne dénombrable du forcing au cadre de la réalisabilité, ce qui semble semble ouvrir une piste prometteuse pour réaliser l'axiome du choix. / Jean-Louis Krivine's classical realizability defines, from any given model of computation and any given model of set theory, a new model of set theory called the realizability model, in a similar way to forcing. Each realizability model is equipped with a characteristic Boolean algebra $\gimel 2$ (gimel 2), whose structure encodes important information about the properties of the realizability model. For instance, forcing models are precisely the realizability models in which $\gimel 2$ is the Boolean algebra with to elements.This document defines new tools for studying realizability models and exploits them to derive new results. One such result is that, as far as first-order logic is concerned, the theory of Boolean algebras with at least two elements is complete for $\gimel 2$, meaning that for each Boolean algebra B (with at least two elements), there exists a realizability model in which $\gimel 2$ is elementarily equivalent to B. Next, two results show that $\gimel 2$ can be used as a tool to study denotational models of programming languages (each one of them takes a particular denotational model and classifies its degrees of parallelism using $\gimel 2$). Moving to set theory, another results generalizes Jean-Louis Krivine's technique of realizing the axiom of dependant choices using the instruction quote to higher forms of choice. Finally, a last result, which is joint work with Laura Fontanella, complements the previous one by adapting the countable antichain condition from forcing to classical realizability, which seems to open a new, promising approach to the problem of realizing the full axiom of choice.
804

Fractional Order Modeling and Control: Development of Analog Strategies for Plasma Position Control of the Stor-1M Tokamak

Mukhopadhyay, Shayok 01 May 2009 (has links)
This work revolves around the use of fractional order calculus in control science. Techniques such as fractional order universal adaptive stabilization (FO-UAS), and the fascinating results of their application to real-world systems, are presented initially. A major portion of this work deals with fractional order modeling and control of real-life systems like heat flow, fan and plate, and coupled tank systems. The fractional order models and controllers are not only simulated, they are also emulated using analog hardware. The main aim of all the above experimentation is to develop a fractional order controller for plasma position control of the Saskatchewan torus-1, modified (STOR-1M) tokamak at the Utah State University (USU) campus. A new method for plasma position estimation has been formulated. The results of hardware emulation of plasma position and its control are also presented. This work performs a small scale test measuring controller performance, so that it serves as a platform for future research efforts leading to real-life implementation of a plasma position controller for the tokamak.
805

Primitive Direcursion and Difunctorial Semantics of Typed Object Calculus

Glimming, Johan January 2007 (has links)
<p>In the first part of this thesis, we contribute to the semantics of typed object calculus by giving (a) a category-theoretic denotational semantics using partial maps making use of an algebraic compactness assumption, (b) a notion of "wrappers'' by which algebraic datatypes can be represented as object types, and (c) proofs of computational soundness and adequacy of typed object calculus via Plotkin's FPC (with lazy operational semantics), thus making models of FPC suitable also for first-order typed object calculus (with recursive objects supporting method update, but not subtyping). It follows that a valid equation in the model induces operationally congruent terms in the language, so that program algebras can be studied. For (c), we also develop an extended first-order typed object calculus, and prove subject reduction. The second part of the thesis concerns recursion principles on datatypes including the untyped lambda calculus as a special case. Freyd showed that in certain domain theoretic categories, locally continuous functors have minimal invariants, which possess a structure that he termed dialgebra. This gives rise to a category of dialgebras and homomorphisms, where the minimal invariants are initial, inducing a powerful recursion scheme (direcursion) on a complete partial order. We identify a problem that appears when we translate (co)iterative functions to direcursion, and as a solution to this problem we develop a recursion scheme (primitive direcursion). This immediately gives a number of examples of direcursive functions, improving on the situation in the literature where only a few examples have appeared. By means of a case study, this line of work is connected to object calculus models.</p> / Delarbete II är även publicerad som Teknisk rapport, 2007, Oct, No2.
806

Sur le comportement effective, l'évolution de microstructure et la stabilité macroscopique des composite élastomères.

Lopez-Pamies, Oscar 20 October 2006 (has links) (PDF)
Les composites élastomères sont actuellement utilisés dans de nombreuses applications commerciales et ont montré de grandes promesses pour l'utilisation dans les nouvelles technologies. Cela soulève la pratique, ainsi que théorique nécessaire pour comprendre le lien entre la microstructure sous-jacente de composites en élastomère et de leurs propriétés mécaniques et physiques, et comment celui-ci peut être améliorée avec des changements dans l'ancienne. Dans ce contexte, l'objectif principal de cette thèse est le développement d'une analyse, le cadre homogénéisation non linéaire pour déterminer la réponse globale des composites élastomères soumis à des déformations finies. Les comptes-cadre pour l'évolution de la microstructure sous-jacente, ce qui entraîne des changements dans la géométrie finie induite par la charge appliquée. Ce point est essentiel que l'évolution de la microstructure peut avoir un assouplissement significatif géométrique (ou raidissage) effet sur la réponse globale du matériau, qui, à son tour, peut conduire à l'élaboration éventuelle d'instabilités macroscopiques. Le concept principal derrière la méthode d'homogénéisation non linéaire proposé est la construction de principes variationnels appropriés en utilisant l'idée d'un "portail composite linéaire», qui a finalement permettre la conversion des estimations disponibles homogénéisation linéaire dans les estimations analytiques pour la grande déformation de réponse global de l' non linéaire des composites en élastomère. Cette thèse comprend des applications de la théorie proposée pour les différentes classes des élastomères renforcés et poreux aléatoire et des microstructures périodiques. Une analyse complète du comportement efficace, l'évolution de la microstructure et le développement d'instabilités macroscopiques est prévu pour toutes ces applications.
807

The relationship of a problem-based calculus course and students' views of mathematical thinking

Liu, Po-Hung 26 August 2002 (has links)
It has been held that heuristic training alone is not enough for developing one's mathematical thinking. One missing component is a mathematical point of view. Many educational researchers have proposed problem-based curricula to improve students' views of mathematical thinking. The present study reports findings regarding effects of a problem-based calculus course, using historical problems, to foster Taiwanese college students' views of mathematical thinking. The present study consisted of three stages. During the initial phase, 44 engineering majors' views on mathematical thinking were tabulated by a six-item, open-ended questionnaire and nine randomly selected students were invited to participate in follow-up interviews. Students then received an 18-week problem-based calculus course in which mathematical concepts were problematized in order to challenge their personally expressed empirical beliefs in doing mathematics. Several tasks and instructional approaches served to reach the goal. Near the end of the semester, all participants answered the same questionnaire and the same students were interviewed to pinpoint their shift in views on mathematical thinking. It was found that participants were more likely to value logical sense, creativity, and imagination in doing mathematics. Further, students leaned toward a conservative attitude in the certainty of mathematical knowledge. Participants focus seemingly shifted from mathematics as a product to mathematics as a process. / Graduation date: 2003
808

Analyzing the Roles of Descriptions and Actions in Open Systems

Hewitt, Carl, Jong, Peter de 01 April 1983 (has links)
This paper analyzes relationships between the roles of descriptions and actions in large scale, open ended, geographically distributed, concurrent systems. Rather than attempt to deal with the complexities and ambiguities of currently implemented descriptive languages, we concentrate our analysis on what can be expressed in the underlying frameworks such as the lambda calculus and first order logic. By this means we conclude that descriptions and actions complement one another: neither being sufficient unto itself. This paper provides a basis to begin the analysis of the very subtle relationships that hold between descriptions and actions in Open Systems.
809

Primitive Direcursion and Difunctorial Semantics of Typed Object Calculus

Glimming, Johan January 2007 (has links)
In the first part of this thesis, we contribute to the semantics of typed object calculus by giving (a) a category-theoretic denotational semantics using partial maps making use of an algebraic compactness assumption, (b) a notion of "wrappers'' by which algebraic datatypes can be represented as object types, and (c) proofs of computational soundness and adequacy of typed object calculus via Plotkin's FPC (with lazy operational semantics), thus making models of FPC suitable also for first-order typed object calculus (with recursive objects supporting method update, but not subtyping). It follows that a valid equation in the model induces operationally congruent terms in the language, so that program algebras can be studied. For (c), we also develop an extended first-order typed object calculus, and prove subject reduction. The second part of the thesis concerns recursion principles on datatypes including the untyped lambda calculus as a special case. Freyd showed that in certain domain theoretic categories, locally continuous functors have minimal invariants, which possess a structure that he termed dialgebra. This gives rise to a category of dialgebras and homomorphisms, where the minimal invariants are initial, inducing a powerful recursion scheme (direcursion) on a complete partial order. We identify a problem that appears when we translate (co)iterative functions to direcursion, and as a solution to this problem we develop a recursion scheme (primitive direcursion). This immediately gives a number of examples of direcursive functions, improving on the situation in the literature where only a few examples have appeared. By means of a case study, this line of work is connected to object calculus models. / Delarbete II är även publicerad som Teknisk rapport, 2007, Oct, No2.
810

Minimizing Travel Time Through Multiple Media With Various Borders

Miick, Tonja 01 May 2013 (has links)
This thesis consists of two main chapters along with an introduction andconclusion. In the introduction, we address the inspiration for the thesis, whichoriginates in a common calculus problem wherein travel time is minimized across two media separated by a single, straight boundary line. We then discuss the correlation of this problem with physics via Snells Law. The first core chapter takes this idea and develops it to include the concept of two media with a circular border. To make the problem easier to discuss, we talk about it in terms of running and swimming speeds. We first address the case where the starting and ending points for the passage are both on the boundary. We find the possible optimal paths, and also determine the conditions under which we travel along each path. Next we move the starting point to a location outside the boundary. While we are not able to determine the exact optimal path, we do arrive at some conclusions about what does not constitute the optimal path. In the second chapter, we alter this problem to address a rectangular enclosed boundary, which we refer to as a swimming pool. The variations in this scenario prove complex enough that we focus on the case where both starting and ending points are on the boundary. We start by considering starting and ending points on adjacent sides of the rectangle. We identify three possibilities for the fastest path, and are able to identify the conditions that will make each path optimal. We then address the case where the points are on opposite sides of the pool. We identify the possible paths for a minimum time and once again ascertain the conditions that make each path optimal. We conclude by briefly designating some other scenarios that we began to investigate, but were not able to explore in depth. They promise insightful results, and we hope to be able to address them in the future.

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