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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.
31

Sustentabilidade na arquitetura e o estudo dos compostos orgânicos voláteis emitidos por componentes vinílicos em habitações / Sustainability in architecture and the study of volatile organic compounds emitted by vinyl components in housings

André Luiz de Oliveira Chaves 02 June 2016 (has links)
Nas últimas décadas, o policloreto de vinila (PVC) tem sido cada vez mais utilizado na Construção Civil, em razão de suas propriedades que o condiciona a substituir outros materiais na execução das obras. Neste caso, tais propriedades são conferidas pela ação de aditivos incorporados na formulação deste polímero, que o torna capaz de ser utilizado em diferentes aplicações, sendo uma delas os revestimentos vinílicos para o recobrimento de superfícies no interior dos edifícios. Entretanto, em pesquisas internacionais, ocorridas a partir dos anos 1990, ficou comprovado que havia a presença de substâncias químicas, denominadas compostos orgânicos voláteis (COV), nestes revestimentos. Diante destes fatores, na presente pesquisa, propôs-se a identificação e quantificação destas substâncias químicas em revestimentos vinílicos para aplicação em pisos e paredes, e nos adesivos de contato (colas), por meio de técnicas analíticas: micro-extração de fase sólida e cromatografia gasosa acoplada a espectrômetro de massas e termogravimetria acoplada ao espectroscópio de infravermelho. Os resultados das análises qualitativas indicaram a presença de compostos pertencentes às classes químicas dos ésteres, éter glicólicos, alcanos, álcoois, cetonas, antioxidantes, ésteres de acetato, terpenos, tióis, organoclorados, solventes hidrocarbonetos e ácido cloreto, encontrados em sua maior parte nas amostras de linhas de piso vinílico e de adesivo de contato, pertencentes à uma das empresas líderes de mercado. Enquanto que as amostras de revestimentos vinílicos de parede não indicaram a presença de COV. Os resultados mais significativos nas análises quantitativas foram obtidos com as amostras de revestimentos, aplicados com adesivo de contato (cola), que indicaram concentrações de 216,41 mg/m³ e de 403,33 mg/m³ do composto 2-etil-1-hexanol, cujos valores estavam acima do limite máximo de 110 mg/m³ estipulado pela norma internacional MAK. Este e outros COVs identificados nesta pesquisa foram analisados quanto aos efeitos que podem causar na saúde humana, se ultrapassarem os limites máximos estabelecidos pelas normas internacionais, que vão desde os efeitos agudos, como irritações de pele, membranas mucosas dos olhos, nariz, garganta e trato respiratório, aos efeitos graves, como doenças neurológicas, distúrbios no ritmo cardíaco, depressão do sistema nervoso, asfixia e câncer. Além de ser verificado se os compostos orgânicos identificados podem contribuir para a redução da qualidade do ar interno das habitações. / In recent decades, the polyvinyl chloride has been increasingly used in civil construction, because of its properties that giving them conditions to replace other materials in the works of buildings. In this case, these properties are conferred by the incorporated additives in the formulation of the polymer, which makes it able to be used in different applications, being part of them the vinyl coverings, inside buildings. However, in international research that took place from the 1990s, it was proved that existed chemicals called volatile organic compounds (VOCs) in these coatings. Given these factors, in the present study aimed to identify and quantify these chemicals in vinyl coatings for use on floors and walls, and contact adhesives (glues), by means of analytical techniques: phase micro-extraction and solid gas chromatography coupled to mass spectrometry and thermogravimetry coupled with infrared spectroscopy. In this case, the additives are incorporated into the formulation of this polymer gives it properties which make it able to be used in different applications, as is the case of vinyl floorings and the vinyl wallpapers, which feature flexible and semi-flexible behavior, due to presence of plasticizers (phthalates) in their formulations. The results of the qualitative analysis showed the presence of compounds belonging to the chemical classes of esters, glycol ether, alkanes, alcohols, ketones, antioxidants, acetate esters, terpenes, thiols, chlorinated, hydrocarbon solvents and acid chloride, found mostly in samples of floor lines and vinyl contact adhesive, both sold in Brazil. While samples of vinyl wall coverings do not indicate the presence of VOC. The most significant results was obtained in quantitative analysis with samples of coatings applied with contact adhesive (glue), which indicated concentrations of 216.41 mg / m³ and 403.33 mg / m³ of the 2-ethyl-1-hexanol compound, whose values were above the upper limit of 110 mg / m³ stipulated by international standard MAK. This and other VOCs identified in this study were analyzed about the effects that can cause human health, if they exceed the limits set by international standards, ranging from the acute effects such as skin irritation, mucous membranes of the eyes, nose, throat and respiratory tract, to the chronic effects such as neurological disorders, heart rhythm disorders, nervous system depression, asphyxia and cancer. In addition to it is verified if the identified organic compounds may contribute to the reduction of the indoor air quality of the houses.
32

Straw-Bale as a Viable, Cost Effective, and Sustainable Building Material for Use in Southeast Ohio

Marks, Leanne R. 20 October 2005 (has links)
No description available.
33

Escopo de projeto para produção de vedações verticais e revestimentos de fachada. / Design for production of partition walls and facade coverings.

Manneschi, Karen 17 November 2011 (has links)
No Brasil, a inserção do projeto para produção de vedações verticais e revestimentos de fachada nas empresas de construção civil gerou métodos de trabalho com melhorias significativas no desenvolvimento e na racionalização dos processos de construção civil. Essas melhorias influenciaram tanto o desempenho quanto as vantagens competitivas para as empresas contratantes. Os projetos para produção, além de oferecer excelentes informações para a tomada de decisões táticas e estratégicas para gerentes e coordenadores de projeto, geram também dados importantes para a equipe de produção, tornando-se uma ferramenta essencial para assegurar a compatibilidade e racionalização construtivas. Alguns pesquisadores têm demonstrado a importância dos projetos para a produção na indústria da construção civil ao propor diretrizes de projeto ou diretrizes técnicas para que esses projetos sejam desenvolvidos. No entanto, nenhum trabalho abordou o escopo essencial que esses projetos devam possuir, nem tampouco em que fase de desenvolvimento cada atividade deve ser elaborada. Esta pesquisa tem por objetivo elaborar uma proposição de escopos de projetos para produção de vedações verticais e revestimentos de fachada e analisar criticamente as mudanças introduzidas nas práticas do planejamento do processo do projeto de cada empresa participante da pesquisa, de maneira a proporcionar referências e documentações que norteiem tanto a que tecnologia construtiva quanto processo de projeto e o planejamento do mesmo na construção civil brasileira. / In Brazil, the incorporation of design for the production of partition walls and facade coverings into construction companies has generated working methods with significant improvements in the construction development and rationalization processes. These improvements affected both the performance and the competitive advantages for companies contractor. The design for production, besides offering excellent information support to enable the design managers to make strategic decisions, also generates important data for the production team, becoming an essential tool for achieving compatibility and rationalization in construction. Some researchers have demonstrated the relevance of production design in the construction industry; however, the content of those designs did not received sufficient attention from academics and professionals. This research aims to describe the elaboration scopes process of the production of partition walls and facade coverings and analyzing the changes made in the practices of the design process of each participating company, from manuals scopes of projects developed in attempt to provide references and documentation that directs the construction technology, the design process and also the planning of it in the Brazilian civil construction.
34

Discrete Geometry in Normed Spaces

Spirova, Margarita 09 December 2010 (has links) (PDF)
This work refers to ball-intersections bodies as well as covering, packing, and kissing problems related to balls and spheres in normed spaces. A quick introduction to these topics and an overview of our results is given in Section 1.1 of Chapter 1. The needed background knowledge is collected in Section 1.2, also in Chapter 1. In Chapter 2 we define ball-intersection bodies and investigate special classes of them: ball-hulls, ball-intersections, equilateral ball-polyhedra, complete bodies and bodies of constant width. Thus, relations between the ball-hull and the ball-intersection of a set are given. We extend a minimal property of a special class of equilateral ball-polyhedra, known as Theorem of Chakerian, to all normed planes. In order to investigate bodies of constant width, we develop a concept of affine orthogonality, which is new even for the Euclidean subcase. In Chapter 2 we solve kissing, covering, and packing problems. For a given family of circles and lines we find at least one, but for some families even all circles kissing all the members of this family. For that reason we prove that a strictly convex, smooth normed plane is a topological Möbius plane. We give an exact geometric description of the maximal radius of all homothets of the unit disc that can be covered by 3 or 4 translates of it. Also we investigate configurations related to such coverings, namely a regular 4-covering and a Miquelian configuration of circles. We find the concealment number for a packing of translates of the unit ball.
35

Algorithmic Construction of Fundamental Polygons for Certain Fuchsian Groups

Larsson, David January 2015 (has links)
The work of mathematical giants, such as Lobachevsky, Gauss, Riemann, Klein and Poincaré, to name a few, lies at the foundation of the study of the highly structured Riemann surfaces, which allow definition of holomorphic maps, corresponding to analytic maps in the theory of complex analysis. A topological result of Poincaré states that every path-connected Riemann surface can be realised by a construction of identifying congruent points in the complex plane, the Riemann sphere or the hyperbolic plane; just three simply connected surfaces that cover the underlying Riemann surface. This requires the discontinuous action of a discrete subgroup of the automorphisms of the corresponding space. In the hyperbolic plane, which is the richest source for Riemann surfaces, these groups are called Fuchsian, and there are several ways to study the action of such groups geometrically by computing fundamental domains. What is accomplished in this thesis is a combination of the methods found by Reidemeister & Schreier, Singerman and Voight, and thus provides a unified way of finding Dirichlet domains for subgroups of cofinite groups with a given index. Several examples are considered in-depth.
36

Escopo de projeto para produção de vedações verticais e revestimentos de fachada. / Design for production of partition walls and facade coverings.

Karen Manneschi 17 November 2011 (has links)
No Brasil, a inserção do projeto para produção de vedações verticais e revestimentos de fachada nas empresas de construção civil gerou métodos de trabalho com melhorias significativas no desenvolvimento e na racionalização dos processos de construção civil. Essas melhorias influenciaram tanto o desempenho quanto as vantagens competitivas para as empresas contratantes. Os projetos para produção, além de oferecer excelentes informações para a tomada de decisões táticas e estratégicas para gerentes e coordenadores de projeto, geram também dados importantes para a equipe de produção, tornando-se uma ferramenta essencial para assegurar a compatibilidade e racionalização construtivas. Alguns pesquisadores têm demonstrado a importância dos projetos para a produção na indústria da construção civil ao propor diretrizes de projeto ou diretrizes técnicas para que esses projetos sejam desenvolvidos. No entanto, nenhum trabalho abordou o escopo essencial que esses projetos devam possuir, nem tampouco em que fase de desenvolvimento cada atividade deve ser elaborada. Esta pesquisa tem por objetivo elaborar uma proposição de escopos de projetos para produção de vedações verticais e revestimentos de fachada e analisar criticamente as mudanças introduzidas nas práticas do planejamento do processo do projeto de cada empresa participante da pesquisa, de maneira a proporcionar referências e documentações que norteiem tanto a que tecnologia construtiva quanto processo de projeto e o planejamento do mesmo na construção civil brasileira. / In Brazil, the incorporation of design for the production of partition walls and facade coverings into construction companies has generated working methods with significant improvements in the construction development and rationalization processes. These improvements affected both the performance and the competitive advantages for companies contractor. The design for production, besides offering excellent information support to enable the design managers to make strategic decisions, also generates important data for the production team, becoming an essential tool for achieving compatibility and rationalization in construction. Some researchers have demonstrated the relevance of production design in the construction industry; however, the content of those designs did not received sufficient attention from academics and professionals. This research aims to describe the elaboration scopes process of the production of partition walls and facade coverings and analyzing the changes made in the practices of the design process of each participating company, from manuals scopes of projects developed in attempt to provide references and documentation that directs the construction technology, the design process and also the planning of it in the Brazilian civil construction.
37

Semigrupos fracamente de Arf e pesos de semigrupos / Near-Arf semigroups and weights of semigroups

Villanueva Zevallos, Juan Elmer 12 August 2018 (has links)
Orientador: Fernando Eduardo Torres Orihuela / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-12T08:34:02Z (GMT). No. of bitstreams: 1 VillanuevaZevallos_JuanElmer_D.pdf: 1127069 bytes, checksum: 8ac303abd191b4c264038dcd1ce40be1 (MD5) Previous issue date: 2008 / Resumo: Os principais tópicos aqui considerados são do tipo aritmético. Introduzimos e estudamos semigrupos que generalizam os chamados semigrupos de Arf. Além de seu interesse particular, eles podem ser usados para esclarecer a estrutura de anéis de semigrupos no sentido de Lipman. Também calculamos os valores exatos dos pesos de semigrupos usando o número de lacunas pares. Isto está relacionado ao recobrimento duplo de curvas e tem interesse no estudo de moduli e constelação de curvas. / Abstract: The main topics considered here are of arithmetical type. We introduce and study semigroups that generalize the so-called Arf semigroups. Apart from being interesting by their own, they may be used to clarify the structure of semigroup rings in the sense of Lipman. We also compute the true value of the weights of semigroups by using the number of even gaps. This is related to double covering of curves and is useful to the study of moduli and constellation of curves. / Doutorado / Geometria Algebrica / Doutor em Matemática
38

Normal and Δ-Normal Configurations in Toric Algebra

Solus, Liam 17 June 2011 (has links)
No description available.
39

Construction of algebraic curves with many rational points over finite fields / Construction of algebraic curves with many rational points over finite fields

Ducet, Virgile 23 September 2013 (has links)
L'étude du nombre de points rationnels d'une courbe définie sur un corps fini se divise naturellement en deux cas : lorsque le genre est petit (typiquement g<=50), et lorsqu'il tend vers l'infini. Nous consacrons une partie de cette thèse à chacun de ces cas. Dans la première partie de notre étude nous expliquons comment calculer l'équation de n'importe quel revêtement abélien d'une courbe définie sur un corps fini. Nous utilisons pour cela la théorie explicite du corps de classe fournie par les extensions de Kummer et d'Artin-Schreier-Witt. Nous détaillons également un algorithme pour la recherche de bonnes courbes, dont l'implémentation fournit de nouveaux records de nombre de points sur les corps finis d'ordres 2 et 3. Nous étudions dans la seconde partie une formule de trace d'opérateurs de Hecke sur des formes modulaires quaternioniques, et montrons que les courbes de Shimura associées forment naturellement des suites récursives de courbes asymptotiquement optimales sur une extension quadratique du corps de base. Nous prouvons également qu'alors la contribution essentielle en points rationnels est fournie par les points supersinguliers. / The study of the number of rational points of a curve defined over a finite field naturally falls into two cases: when the genus is small (typically g<=50), and when it tends to infinity. We devote one part of this thesis to each of these cases. In the first part of our study, we explain how to compute the equation of any abelian covering of a curve defined over a finite field. For this we use explicit class field theory provided by Kummer and Artin-Schreier-Witt extensions. We also detail an algorithm for the search of good curves, whose implementation provides new records of number of points over the finite fields of order 2 and 3. In the second part, we study a trace formula of Hecke operators on quaternionic modular forms, and we show that the associated Shimura curves of the form naturally form recursive sequences of asymptotically optimal curves over a quadratic extension of the base field. Moreover, we then prove that the essential contribution to the rational points is provided by supersingular points.
40

Arakelov inequalities and semistable families of curves uniformized by the unit ball / Inégalités d'Arakelov et familles semistable de courbes uniformisées par la boule

Damjanovic, Nikola 14 June 2018 (has links)
L'objet principal de cette thèse est de démontrer une inégalité d'Arakelov qui consiste à borner le degré d'un sous-faisceau inversible de l'image directe d'un faisceau relatif pluricanonique d'une famille semi-stable de courbes. Un problème naturel qui apparaît est la caractérisation des familles pour lesquelles sont satisfaites le cas d'égalité dans l'inégalité d'Arakelov, i.e. le cas d'égalité d'Arakelov. Peu d'exemples de telles familles sont connus. Dans cette thèse nous en proposons plusieurs en prouvant que le faisceau relatif bicanonique d'une famille semi-stable de courbes uniformisée par la boule unité et dont toutes les fibres singulières sont totalement géodésiques contient un sous-faisceau inversible qui satisfait l'égalité d'Arakelov. / The main object of study in this thesis is an Arakelov inequality which bounds the degree of an invertible subsheaf of the direct image of the pluricanonical relative sheaf of a semistable family of curves. A natural problem that arises is the characterization of those families for which the equality is satisfied in that Arakelov inequality, i.e. the case of Arakelov equality. Few examples of such families are known. In this thesis we provide some examples by proving that the direct image of the bicanonical relative sheaf of a semistable family of curves uniformized by the unit ball, all whose singular fibers are totally geodesic, contains an invertible subsheaf which satisfies Arakelov equality.

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