Este trabalho apresenta formulações para a análise de associação de chapas, usando o conceito de sub-regiões. Também é apresentada a técnica da sub-estruturação para o método dos elementos de contorno. O aumento da rigidez no contínuo através de enrijecedores é considerada pela combinação do método dos elementos finitos e do método dos elementos de contorno. Neste procedimento o sistema de equações lineares torna-se semelhante ao encontrado na formulação do método dos elementos de contorno. Através desta formulação é também possível simular o escorregamento entre superfícies rígidas usando modelos plásticos e visco-plásticos simples do tipo coulomb. Isto representa a descontinuidade nos esforços e deslocamentos entre chapas. São, ainda, apresentados exemplos de aplicação para demonstrar a validade da formulação utilizada. / This work presents formulations for analysis of plate association, using the concept of sub-regions. It is also presented the substructure technique for the boundary elements method. The increasing in stiffiness in the continuous is considered by the combinations of the finite and boundary element methods. In this procedure the linear equation system becomes similar to the resulted by boundary element method. The formulation used also alows to simulate the slipping among rigid surfaces using plastic and simple viscous-plastic models of Coulomb type. This represents the descontinues in the forces and displacements among plates. It was also presented some numeric examples in order to validate the formulation used.

Made available in DSpace on 2016-08-10T10:44:11Z (GMT). No. of bitstreams: 1 Leonardo de Assis Italo.pdf: 2826287 bytes, checksum: f7cd22859dc671fee66ed444ed64ed6f (MD5) Previous issue date: 2009-12-11 / Studies on the biodiversity of the Cerrado has focused on vertebrate animals and plants, but there are few studies on aquatic insects in Goiás, more specifically in the basin of the Araguaia River. This study aims to compare the assemblages of insects among the sampled water courses and determine which the insect-substrate patterns are. Samples were taken in 24 sampling points distributed in 11 rivers and one tributary (stream). It was collected 11,759 insects distributed in 42 families and nine orders. The ecological descriptors used indicated significant differences among the river aquatic insects assemblages that seems related to its location in environments rich in organic matter, such as the water courses located in the Middle Araguaia floodplain, or in a local submitted to anthropogenic interferences. The larvae of the Chironomidae and Ceratopogonidae family are associated with a substrate composed by leaves and it is explained by the use of this substrate as insect food source. The Simuliidae and Coenagrionidae display preference for substrates of pebbles, which seem to be related to dietary habits and ecological aspects. / Os estudos sobre a biodiversidade do Cerrado tem se centrado em animais vertebrados e plantas, mas poucos são os estudos sobre os insetos aquáticos em Goiás, mais especificamente na bacia do rio Araguaia. Este trabalho tem como objetivo comparar as assembléias de insetos entre os cursos de águas amostrados e determinar quais são os padrões da relação inseto-substrato. As amostras foram realizadas em 24 estações de coleta distribuídos em 11 rios e um afluente (córrego). Foram coletados 11759 insetos distribuídos em 42 famílias e nove ordens. Os descritores ecológicos utilizados indicam existir diferenças entre as assembléias de insetos aquáticos dos cursos de água que parecem relacionados à sua localização, seja em ambientes ricos em matéria orgânica, como é o caso dos cursos de água localizados na planície de inundação do médio Araguaia, seja em locais com interferências antrópicas. As larvas da família Chironomidae e Ceratopogonidae estão associadas a um substrato de folhas, explicada pelo uso das mesmas como alimento por parte destes insetos. Os Simuliidae e Coenagrionidae apresentam preferência por substratos de seixos, que parecem estar relacionados com os seus hábitos alimentares e aspectos ecológicos.

Neste trabalho foram realizados experimentos de soldagem de chapas de Tântalo e Monel 400 com 100 m de espessura. Foram realizadas soldas em um laser de Nd:YAG operando em modo pulsado e em um Laser de Fibra operando em modo contínuo. Em seguida a microestrutura das amostras foram analisadas através de microscopia ótica e foram realizados ensaio de microdureza Vickers. As amostras que apresentaram melhores resultados foram submetidas a ensaios de tração e a ensaios de corrosão. Após análise dos resultados observou-se que a soldagem a laser apresenta muitos benefícios em relação a outros processos convencionais para chapas finas. A soldagem no modo pulsado apresentou maior relação de aspecto se comparado a soldagem em modo contínuo. A soldagem em modo contínuo apresentou uma velocidade de soldagem muito superior ao modo pulsado. Os resultados indicaram que a soldagem no modo pulsado apresenta maior aplicabilidade para chapas finas, devido à necessidade um controle preciso sobre a intensidade aplicada. / This work carried out welding experiments of Tantalum and Monel 400 plates with 100 mm thickness. Welds were made with an Nd: YAG laser operating in a pulsed mode and in a fiber laser operating in continuous mode. Then the microstructure of the samples were analyzed by optical microscopy and were performed Vickers microhardness test. Samples that showed better results were subjected to tensile tests and the corrosion tests. After analysis of the results showed that the laser welding offers many benefits over other conventional processes for thin sheets. The welding in pulsed mode presented in superior aspect ratio compared to welding in continuous mode. The welding in continuous mode showed a much higher welding speed to pulsed mode. The results indicated that the welding in pulsed mode shows more applicability for sheet metal, due the need of a precise control of applied intensity.

Este trabalho tem por objetivo principal a elaboração de fichas técnicas de materiais utilizados na fabricação de órteses de membro superior e inferior. Para a escolha dos materiais a serem elencados e caracterizados, selecionou-se as instituições de apoio ao deficiente da área metropolitana de Porto Alegre, RS. As selecionadas para a pesquisa foram a Associação de Assistência à Criança com Deficiência (AACD) e Associação Canoense de Deficientes Físicos (ACADEF). A metodologia abordou a listagem e seleção, e as etapas seguintes se deram a partir da organização dos materiais em grandes grupos: materiais poliméricos, materiais metálicos, materiais naturais e fibras. Assim agrupados, seguiu-se a caracterização e a análise dos materiais por meio de microscopia eletrônica de varredura (MEV), espectroscopia por energia dispersiva (EDS), espectroscopia no infravermelho por transformada de Fourier (FT-IR), espectrometria de fluorescência de raios-X e ensaio de tração e compressão. Os resultados práticos e as pesquisas em materiais bibliográficos e bancos de dados como o Granta Design permitiram a elaboração das fichas técnicas de cada material, apresentando as características gerais, propriedades físicas, mecânicas e químicas e aplicação. Essas fichas têm finalidade multidisciplinar, buscando auxiliar profissionais que trabalham no processo de fabricação destas órteses, como fisioterapeutas, terapeutas ocupacionais, técnicos de oficina, designers e projetistas, permitindo acesso direto e praticidade na fabricação destes produtos. / The main objective of this study is to develop technical sheets of materials utilized in the manufacturing of superior and inferior limb orthoses. Institutions that support disabled persons in the metropolitan area of Porto Alegre, RS, were selectioned in order to decide which materials were to be listed and characterized. The Association of Assistance for Children with Disability (AACD) and the Canoense Association of persons with Physical Disability (ACADEF) were selected for this research. Methods included listing and selection, and the following steps were conducted through the categorization of materials into large groups: polymeric materials, metal materials, natural materials and fibers. Thus grouped, the study continued with the characterization and analysis of materials through scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), X-ray fluorescence spectrometry and tension and compression testing. Practical results and research in bibliographical material and databases such as Granta Design enabled the development of technical sheets for each material, presenting general characteristics, physical, mechanical and chemical properties and application. Such sheets have multidisciplinary purposes, seeking to assist health professionals who work in the manufacturing process of these orthoses, such as physiotherapists, occupational therapists, workshop technicians, designers and drafters, allowing for direct access and convenience in the manufacturing of these products.

Aços de alta resistência e baixa liga (HSLA) tem sido amplamente empregados na indústria nos últimos anos, em especial na indústria automotiva, com a finalidade de reduzir peso dos produtos sem prejudicar características importantes como a resistência. O aço LNE 380 vem sendo aplicado na fabricação de peças mais robustas e que passam por processos de dobra. Dessa forma, esse estudo tem como objetivo principal determinar as deformações máximas causadas pelas tensões de tração em chapas do aço de alta resistência e baixa liga NBR 6656 LNE 380 submetidas ao processo de dobramento. Chapas de 6,35mm de espessura foram inicialmente analisadas por meio de ensaios de tração para verificar as propriedades mecânicas do aço. Os ensaios de tração apresentaram uma tensão de escoamento de 469±8MPa e tensão máxima de resistência de 539±3MPa. O ensaio de dobramento semiguiado foi utilizado para detectar o nível de deformação na região externa das chapas, ocasionado pelos esforços de tração durante o processo, bem como seu retorno elástico. No ensaio de dobramento utilizaram-se três raios de punçãovariando o deslocamento do mesmo para se obter diferentes raios de dobra. As máximas deformações relativa e verdadeira foram medidas na região externa da dobra, e posteriormente comparadas com resultados teóricos a fim de validar equações indicadas na bibliografia. Os valores teóricos variaram conforme o raio do punção, diferente do observado nos ensaios, onde a deformação permaneceu a mesma para todos os três raios utilizados. A maior deformação, calculada e medida, refere-se ao ensaio realizado com o menor raio de punção, assim como o maior Fator de Retorno Elástico. Verificou-se que no ensaio de dobramento, para o aço LNE 380, nas condições pré-definidas, a variação do raio do punção não interferiu de forma significativa nos resultados, uma vez que, as deformações e retorno elástico medido obteram valores próximos para diferentes raios. / High Strength Low Alloy (HSLA) steels have been widely used in the industry in the last years, especially in the automotive industry, in order to reduce weight products without impairing important characteristics such as strenght. The LNE 380 steel has been applied in the manufacture of more robust parts and that go through bending process. Therefore, this study has as main objective to determine the maximum deformation caused by the tensile stresses in sheets of High Strength Low Alloy steel NBR 6656 LNE 380 submitted to bending process. Sheets of 6,35mm thick were initially analyzed by tensile tests to verify the mechanical properties of the steel. The tensile tests showed a yield stress of 469±8 and maximum tensile strength of 539±3. The semi-guided bending test was used to detect the level of deformation in the external fibers of the sheets, caused by tensile stresses during the process, as well as their springback. Three punch radii were used in the bending test varying their displacement to achieve different bending radii. The maximum relative and true deformations were measured in the outer region of the bend, and subsequently compared with theoretical results in order to validate equations used in the bibliography. The theoretical values varied according to the punch radius that was different from those observed in the tests, where the deformation remained the same for all three radii used. The largest deformation calculated and measured refers to the test performed with the smallest punch radius, as well as the largest springback fator. It was observed that in the bending process, for the LNE 380 steel, under the pre-defined conditions, the variation of the punch radius did not interfein the results significally, since the values of deformation and springback measured were similar for different radii.

The internal structure of ice sheets reflects the history of flow and deformation experienced by the ice mass. Flow and deformation are controlled by processes occurring within the ice mass and at its boundaries, including surface accumulation or ablation, ice rheology, basal topography, basal sliding, and basal melting or freezing. The internal structure and basal environment of ice sheets is studied with ice-penetrating radar. Recently, radar observations in Greenland and Antarctica have imaged large englacial structures rising from near the bed that deform the overlying stratigraphy into anticlines, synclines, and overturned folds. The mechanisms that may produce these structures include basal freeze-on, travelling slippery patches at the ice base, and rheological contrasts within the ice column. In this thesis, I explore the setting and mechanisms that produce large basal stratigraphic structures inside ice sheets. First, I use radar data to map subglacial hydrologic networks that deliver meltwater uphill towards freeze-on structures in East Antarctica. Next, I use a thermomechanical flowline model to demonstrate that trains of alternating slippery and sticky patches can form underneath ice sheets and travel downstream over time. The disturbances to the ice flow field produced by these travelling patches produce stratigraphic folds resembling the observations. I then examine the overturned folds produced by a single travelling sticky patch using a kinematic flowline model. This model is used to interpret stratigraphic measurements in terms of the dynamic properties of basal slip. Finally, I use a simple local one-dimensional model to estimate the thickness of basal freeze-on that can be produced based on the supply of available meltwater, the thermal boundary conditions, ice sheet geometry, and the ice flow regime.

Existing reinforced concrete bridges may be deemed inadequate to carry the ever-increasing traffic loads according to the current codes and standards before they reach the end of their design life. It may therefore be required to either strengthen or replace these structures, which can be costly and causes disruptions to the infrastructure. This work investigates experimentally the possibilities to extend the useful life of existing reinforced concrete slab-on-beam structures deficient in shear by means of structural strengthening with fibre-reinforced polymers (FRP). The experimental campaign involved mechanical testing of ten full-scale T-beam specimens, representative of typical existing slab-on-beam bridges. Two sizes of test specimen were used to investigate the effect of size on the ultimate shear capacity of the beams. The investigated shear-strengthening configurations included externally bonded carbon fibre reinforced polymer (CFRP) sheets in a U-wrap configuration with and without end-anchorage and deep embedded CFRP bars. Unstrengthened control specimens were also tested to provide baseline for comparison. The results from the experimental programme revealed that while the deep embedment strengthening solution provides an increase in shear capacity of up to 50%, the strengthening with CFRP U-wraps results in reduced capacity compared with the underlying control beam. This presents a major implication in terms of safe design predictions of shear capacity of reinforced concrete T-beams strengthened with CFRP sheets as this is the most commonly used shear-strengthening scheme in practice. The study also demonstrated that greater contribution from the externally bonded CFRP U-wraps can be achieved using end-anchorage systems, which delay the debonding of the CFRP. The applicability of current codes of standards and guidelines was studied as well as appropriateness of using advanced numerical methods for assessment of existing reinforced concrete structures. It was found that while the standards used for assessment greatly under-predict the shear capacity, the guidelines for FRP-strengthened beams either under- or over-predict the shear capacity of the tested beams. More accurate predictions are possible using advanced fracture mechanics-based methods for both the unstrengthened as well as the strengthened beams.

Submitted by Aline Batista (alinehb.ufpel@gmail.com) on 2018-04-13T18:31:46Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_Aline_Silveira_Cardoso_Oliveira.pdf: 2264789 bytes, checksum: 935fe6affb42c7bd8ef6d0e2d3a89651 (MD5) / Made available in DSpace on 2018-04-13T19:59:09Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_Aline_Silveira_Cardoso_Oliveira.pdf: 2264789 bytes, checksum: 935fe6affb42c7bd8ef6d0e2d3a89651 (MD5) Previous issue date: 2006-09-12 / Sem bolsa / A prática da fitoterapia segura não se verifica apenas por meio da análise do produto final, mas também, na obtenção da espécie vegetal, desde sua identificação, cultivo, colheita, beneficiamento, armazenamento e comercialização. A ausência de qualidade, a adulteração e a utilização incorreta podem interferir na eficácia e até mesmo na segurança do uso do produto. Uma das espécies amplamente utilizada tanto na medicina popular quanto no sistema oficial de saúde é a Maytenus ilicifolia Mart ex Reissek (espinheira-santa) para o tratamento de dispepsias. O objetivo deste trabalho foi avaliar os parâmetros de qualidade das amostras secas de espinheira-santa disponíveis nos locais de comercialização formal na cidade de Pelotas. Este estudo tem delineamento classificado como descritivo experimental e analítico. Foram coletadas 11 amostras de plantas medicinais popularmente conhecidas como cancorosa e/ou espinheira-santa, vendidas no comércio formal (farmácias, drogarias e supermercados) e uma amostra padrão coletada no Instituto Federal Sul-rio-grandense, Campus Pelotas - Visconde da Graça. Foram avaliadas características organolépticas e físico-químicas, além dos rótulos dos produtos. Todas as amostras foram reprovadas em pelo menos dois parâmetros analisados, indicando que é necessário ampliar a fiscalização visando garantir a segurança ao consumidor. / The practice of safe phytotherapy does not occur only through the analysis of the final product, but also in obtaining the plant species, from its identification, growing, harvest, processing, storage, and commercialization. The lack of quality, adulteration, and the misuse may interfere with the efficacy and even in the safe use of the product. One of the widely used species is Maytenus ilicifolia Mart ex Reissek (espinheira-santa), which is a common practice both in popular medicine and official health system for treatment of dispepsy. The objective of this work was evaluate the parameters of quality of dry samples of „espinheira-santa‟ available in formal local marketing in the municipality of Pelotas. The design of this study is descriptive, experimental and analytical. Eleven samples of medicinal plants popularly known as „cancorosa‟ and/or „espinheira-santa‟ were collected from formal marketing (pharmacies, drugstores and super markets), and a standard sample was collected from Instituto Federal Sul Riograndense, Campus Pelotas – Visconde da Graça. Physico-chemical and organoleptic characteristics were evaluated, as well as the labels of the products. All samples were not approved at least in two parameters analyzed, indicating that is necessary to expand surveillance to ensure consumer safety.

Herein we consider material tensors that pertain to thin sheets or thin films, which we model as two-dimensional objects. We assume that the thin sheet in question carries a crystallographic texture characterized by an orientation distribution function defined on the rotation group SO(3), which is almost transversely-isotropic about the sheet normal so that mechanical and physical properties of the thin sheet have weak planar-anisotropy. We present a procedure by which a special orthonormal basis can be determined in each tensor subspace invariant under the action of the orthogonal group O(2). We call members of such special bases irreducible basis tensors under O(2). For the class of thin sheets in question, we derive a representation formula in which each tensor in any given tensor subspace Z is written as the sum of a transversely-isotropic term and a linear combination of orthonormal irreducible basis tensors in Z, where the coefficients are given explicitly in terms of texture coefficients and undetermined material parameters. In addition to the general representation formula, we present also the specialized form for subspaces of tensor products of second-order symmetric tensors, a type commonly found in mechanics of materials.

Subglacial water plays an important role in the regulation of an ice sheet's mass balance. It may be the dominant control on the velocities of ice streams and outlet glaciers on scales of months to millennia. Recent satellite observations of ice surface elevation changes have given researchers new insights into how subglacial water is stored and transported. Localized uplift and settling of the ice surface implies that lakes exist beneath the ice sheet that are being filled and drained on relatively short time scales. %At the base of an ice sheet water can be transported through a variety of drainage networks or stored in subglacial lakes. Here, a numerical investigation of the mechanisms of transport and storage of subglacial water and the associated time scales is presented. Experiments are carried out using a finite element model of coupled ice and water flow. The first experiment seeks to understand the relationship between the depth of a basal depression and the area over which the feature affects basal water flow. It is found that as the perturbation to a topographic depression's depth is increased, water is rerouted in response to the perturbation. Additionally it is found that the relationship between perturbation depth and the extent upstream to which its effects reach is nonlinear. The second experiment examines how the aspect ratio of bed features (prolate, oblate, or equidimensional) influences basal water flow. It is found that the systems that develop and their interactions are mediated by both the topography and the feedbacks taken into account by the coupling of the systems in the model. Features oriented parallel to ice and water flow are associated with distributed fan systems that develop branches which migrate laterally across the domain and interact with one another on monthly and yearly timescales. Laterally oriented features develop laterally extensive ponds. As the ratio of longitudinal to lateral dimension of the topography is increased, a combination of these two water distributions is seen.