Axial buckling load of partially encased columns under fire

Partially encased columns have significant fire resistant. However, it is not possible to assess the fire resistance of such members simply by considering the temperature of the steel. The presence of concrete increases the mass and thermal inertia of the member and the variation of temperature within the cross section, in both the steel and concrete components. The annex G of EN1994-1-2 allows to calculate the load carrying capacity of partially encased columns, for a specific fire rating time, considering the balanced summation method. New formulas will be used to calculate the plastic resistance to axial compression and the effective flexural stiffness. These two parameters are used to calculate the buckling resistance. The finite element method is used to compare the results of the elastic critical load for different fire ratings of 30 and 60 minutes. The buckling resistance is also calculated by the finite element method, using an incremental and iterative procedure. This buckling resistance is also compared with the simple calculation method, evaluating the design buckling curve that best fits the results.

Presença de isquemia na cintigrafia de perfusão miocárdica na ausência de estenose coronária relevante

Problemática em estudo: A frequente ocorrência da ausência de estenose coronária relevante no procedimento de Hemodinâmica/Tomografia Axial Computorizada (TAC) coronária, em pacientes nos quais fora detectada a presença de isquemia na Cintigrafia de Perfusão Miocárdica (CPM). Objectivos: Particularizar o papel das técnicas nucleares convencionais, nomeadamente a Tomografia Computorizada por Emissão de Fotão Único (SPECT), no estudo da viabilidade do tecido miocárdico. Avaliar pacientes nos quais foi identificada a presença de isquemia no exame de SPECT cardíaco mas procedimento de Hemodinâmica/TAC coronária normal ou sem estenose relevante, para pesquisa de possíveis falsos-positivos da CPM. Elaborar um estudo populacional, que permita demonstrar a relação entre a incidência de falsos positivos e factores como o género, a idade, factores de risco (hipertensão arterial, diabetes, hipercolesterolemia e tabagismo) e as alterações mais relevantes nos exames complementares de diagnóstico aos quais foram sujeitos. Definir o prognóstico para estes doentes, comparando-os com pacientes com CPM normal. Metodologia: Contextualização bibliográfica do tema, seguida do levantamento de todas as CPM realizadas no 1º semestre de 2012, em doentes seguidos no Centro Hospitalar Cova da Beira (CHCB), e a identificação daquelas com resultados positivos para a presença de isquemia; comparação com os exames de Hemodinâmica e TAC coronária para a pesquisa de falsos-positivos. Recolha de informação relativa à idade, género, factores de risco, eventos cardíacos que tenham tido lugar até um ano após a realização da CPM, e outros exames efectuados por estes pacientes, tais como o Electrocardiograma (ECG) e o Ecocardiograma. Análise estatística descritiva e inferencial dos resultados obtidos de forma a estabelecer/descartar a existência de relações entre as variáveis em estudo. Comparação dos resultados obtidos em relação a um grupo de controlo, integrado por pacientes com CPM normal realizada no mesmo período, com a elaboração de uma proposta de prognóstico para os casos falsos-positivos. Material: A recolha de dados foi baseada na Tabela de Recolha de Dados, enviada em Anexo. Os processos consultados eram processos de natureza electrónica, acessíveis por computador, através do programa Sclínico, no Gabinete de Biblioteca e Documentação do CHCB. A análise estatística dos resultados obtidos foi realizada com recurso ao programa IBM SPSS Statistics 21. Para a caracterização da amostra recorreu-se à estatística descritiva, sendo analisadas as medidas de tendência central e de dispersão (média e desvio padrão), bem como a distribuição de frequências, quer absolutas, quer relativas. Seguiu-se a inferência estatística, com o intuito de verificar possíveis relações existentes entre as variáveis. Para isso foram utilizados testes paramétricos ou não paramétricos, adequados à amostra e hipóteses em estudo, nomeadamente o teste t de Student, com recurso ainda ao teste Kolmogorov-Smirnov com correcção de significância de Lilliefors e do teste de Levene. Foi ainda utilizado o teste Qui-Quadrado e, na ausência dos pressupostos para sua aplicação, recorreu-se ao teste exacto de Fisher. Resultados/Discussão: Foi estudada uma amostra total de 144 casos de pacientes submetidos a CPM. Desta amostra foram particularizados 2 grupos; um grupo de controlo (n=81) e um grupo de falsos positivos (n=13) e analisadas as principais diferenças entre estes 2 grupos, tendo em conta as variáveis anteriormente descritas. As principais diferenças, identificadas do ponto de vista da estatística descritiva, verificaram-se ao nível do tipo de stress (farmacológico; falsos positivos - 63.64%, grupo de controlo – 40.74%), factores de risco (hipercolesterolemia; falsos positivos - 53.85%, grupo de controlo – 29.63%), ECG (fibrose; falsos positivos - 16.67%, grupo de controlo – 0%), Ecocardiograma (alteração da contractilidade segmentar; falsos positivos - 33.33%, grupo de controlo – 14.86%) e em relação aos eventos cardíacos posteriores (falsos positivos - 7.69%; grupo de controlo - 4.94%). A estatística inferencial permitiu apenas estabelecer uma relação estatisticamente significativa entre a existência de fibrose no ECG e a ocorrência de falsos positivos. Conclusão: Este estudo permitiu concluir que, de uma forma puramente descritiva, os casos falsos positivos se verificam mais predominantemente numa faixa etária média de 73.69 anos, no género feminino, com a localização das lesões na CPM a ser mais frequente no apex e mais rara no septo interventricular. O stress descritivamente mais associado a estes casos foi o stress farmacológico, com uma fracção de ejecção igual ou superior a 50%, com dois factores de risco associados, sendo os mais prevalentes a hipertensão arterial (HTA) e a hipercolesterolemia, sendo no entanto, este último, o factor de risco mais diferenciador em relação aos restantes casos. A maioria dos casos, em termos descritivos, não apresenta alterações no ECG, mas a existirem, a que mais se verifica é a fibrose. Relativamente ao ecocardiograma, existe uma maior prevalência de casos nos quais se verificam alterações neste exame complementar de diagnóstico, sendo a hipertrofia das paredes e a alteração da contractilidade segmentar do VE as alterações mais importantes, sendo, no entanto, este último, o factor mais diferenciador/característico. A prevalência descritiva de eventos cardíacos, num período de tempo após um ano da realização da CPM, é reduzida nos casos falsos positivos, mas ainda assim, superior à verificada nos restantes casos, o que em termos comparativos pressupõe uma deterioração em termos de prognóstico para estes pacientes. A análise estatística inferencial dos resultados obtidos permitiu apenas uma correlação entre a existência de fibrose no ECG e a ocorrência de falsos positivos. A análise de uma população geral de maiores dimensões, que permitisse a identificação de um número de falsos positivos igual ou superior a 30, possibilitaria, muito provavelmente, uma maior relação entre as diferentes amostragens e, consequentemente, uma base estatística que permitisse a obtenção de conclusões mais sólidas, estabelecendo/descartando as relações entre as várias variáveis em estudo, sendo esta, uma importante premissa a ter em conta para estudos futuros.

Relações de cooperação em consórcios públicos de regiões metropolitanas: análises do CONDIAM/PB e consórcio grande Recife

With the disorganized decentralization occurred in Brazil after the 1988 Constitution, municipalities have risen to the level of federal entities. This phenomenon became known as "municipalism" also brought some negative effects such as low capacity financial, economic and political of these entities. In the face of this reality , the municipalities sought in models of collaborative features to address public policy issues ultrarregionais, one of these models are the Public Consortia. Characterized as the organization of all federal entities that aim to solve public policy implementation alone that they could not, or spend great resources for such. This reality of the municipalities have an aggravating factor when looking at the situation in Metropolitan Regions (MRs). This is because the RMs has a historical process of formation that does not encourage cooperation, since that were created top-down during the military regime. Furthermore, the metropolitan municipalities have significant power asymmetries, localist vision, rigidity earmarked revenues, different scenarios conurbation, difficulty standardization of concepts and others that contribute to the vision of low cooperation of these metropolitan areas. Thus, the problem of this work is in the presence of collaborative arrangements, such as the Public Consortia in metropolitan areas, which are seen as areas of low cooperation. To elucidate this research was used for analysis the cases of CONDIAM/PB and Consórcio Grande Recife/PE, because they are apparently antagonistic, but with some points of similarity. The cases has as foundation the Theory of Common Resources, which provides the possibility of collective action through the initiative of individuals. This theory has as its methodology for analyzing the picture IAD Framework, which proposes its analysis based on three axes: external variables, the arena of action and results. The nature of the method of this research was classified as exploratory and descriptive. For the stage of date analysis, was used the method of document analysis and content, Further than of separation of the cases according to theur especificities. At the end of the study, noted that the CONDIAM/PB was a strategy of municipal government of Joao Pessoa to attract funds from the Federal Government for the purpose of to build a landfill, and over the years the ideology of cooperation was left aside, the prevailing view localist municipalities. In the case of Consórcio Grande Recife/PE, members act with some degree of cooperation, especially the collaborative aspect of the region, however, still prevails with greater strength the power of the state of Pernambuco in the decisions and paths of the consortium. Thus, was conclude that the Public Consortia analyzed are an experience of collaborative arrangement, from the initiative of members, as the theory of common resources says, but has not actually signed as a practice of collective action to overcome the dilemmas faced by metropolitan areas

Análise experimental do comportamento à flexão e ligação entre painéis de lajes tipo bubbledeck

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2016.

Desenvolvimento de tubulação em compósito polimérico revestida externamente com poliuretano de alta densidade

Pipelines for the transport of crude oil from the production wells to the collecting stations are named production lines . These pipes are subjected to chemical and electrochemical corrosion according to the environment and the type of petroleum transported. Some of these lines, depending upon the composition of the fluid produced, may leak within less than one year of operation due to internal corrosion. This work aims at the development of composite pipes with an external protecting layer of high density polyurethane for use in production lines of onshore oil wells, meeting operational requirements. The pipes were manufactured using glass fibers, epoxy resin, polyester resin, quartz sand and high density polyurethane. The pipes were produced by filament winding with the deposition of high density polyurethane on the external surface and threaded ends (API 15 HR/PM-VII). Three types of pipes were manufactured: glass/epoxy, glass/epoxy with an external polyurethane layer and glass/epoxy with an intermediate layer of glass fiber, polyester, sand and with an external polyurethane layer. The three samples were characterized by Scanning Electronic Microscopy (SEM) and for the determination of constituent content. In addition, the following tests were conducted: hydrostatic test, instant rupture, shorttime failure pressure, Gardner impact, transverse stiffness and axial tension. Field tests were conducted in Mossoró RN (BRAZIL), where 1,677 meters of piping were used. The tests results of the three types of pipes were compared in two events: after two months from manufacturing of the samples and after nine months of field application. The results indicate that the glass/epoxy pipes with an intermediate layer of fiber glass composite, polyester e sand and with an external layer of high density polyurethane showed superior properties as compared to the other two and met the requirements of pressure class, axial tensile strength, transverse stiffness, impact and environmental conditions, for onshore applications as production lines

Otimização e análise mecânica de pastas geopoliméricas para uso em poços sujeitos à injeção cíclica de vapor

Oil wells subjected to cyclic steam injection present important challenges for the development of well cementing systems, mainly due to tensile stresses caused by thermal gradients during its useful life. Cement sheath failures in wells using conventional high compressive strength systems lead to the use of cement systems that are more flexible and/or ductile, with emphasis on Portland cement systems with latex addition. Recent research efforts have presented geopolymeric systems as alternatives. These cementing systems are based on alkaline activation of amorphous aluminosilicates such as metakaolin or fly ash and display advantageous properties such as high compressive strength, fast setting and thermal stability. Basic geopolymeric formulations can be found in the literature, which meet basic oil industry specifications such as rheology, compressive strength and thickening time. In this work, new geopolymeric formulations were developed, based on metakaolin, potassium silicate, potassium hydroxide, silica fume and mineral fiber, using the state of the art in chemical composition, mixture modeling and additivation to optimize the most relevant properties for oil well cementing. Starting from molar ratios considered ideal in the literature (SiO2/Al2O3 = 3.8 e K2O/Al2O3 = 1.0), a study of dry mixtures was performed,based on the compressive packing model, resulting in an optimal volume of 6% for the added solid material. This material (silica fume and mineral fiber) works both as an additional silica source (in the case of silica fume) and as mechanical reinforcement, especially in the case of mineral fiber, which incremented the tensile strength. The first triaxial mechanical study of this class of materials was performed. For comparison, a mechanical study of conventional latex-based cementing systems was also carried out. Regardless of differences in the failure mode (brittle for geopolymers, ductile for latex-based systems), the superior uniaxial compressive strength (37 MPa for the geopolymeric slurry P5 versus 18 MPa for the conventional slurry P2), similar triaxial behavior (friction angle 21° for P5 and P2) and lower stifness (in the elastic region 5.1 GPa for P5 versus 6.8 GPa for P2) of the geopolymeric systems allowed them to withstand a similar amount of mechanical energy (155 kJ/m3 for P5 versus 208 kJ/m3 for P2), noting that geopolymers work in the elastic regime, without the microcracking present in the case of latex-based systems. Therefore, the geopolymers studied on this work must be designed for application in the elastic region to avoid brittle failure. Finally, the tensile strength of geopolymers is originally poor (1.3 MPa for the geopolymeric slurry P3) due to its brittle structure. However, after additivation with mineral fiber, the tensile strength became equivalent to that of latex-based systems (2.3 MPa for P5 and 2.1 MPa for P2). The technical viability of conventional and proposed formulations was evaluated for the whole well life, including stresses due to cyclic steam injection. This analysis was performed using finite element-based simulation software. It was verified that conventional slurries are viable up to 204ºF (400ºC) and geopolymeric slurries are viable above 500ºF (260ºC)

Currículo universitário: da geometria cartesiana à relatividade einsteiniana

A dimensão das questões curriculares, no ensino superior universitário, transcende, cada vez mais, os tradicionais, mas de crescente complexidade, campos do ensino e da aprendizagem. Na Universidade, para além de se ensinar e aprender, também se vive. Vive-se um dos períodos mais marcantes das vidas de cada um: a época em que se é jovem adulto. A uma organização curricular, institucionalmente ortodoxa, baseada na rigidez dos planos de estudo, dos horários e locais de trabalho e dos conhecimentos a adquirir, contrapõe-se, cada vez mais, uma procura personalizada de produtos educativos personalizados, flexíveis e adaptáveis às características, necessidades e contextos de quem os procura. O design curricular, no âmbito universitário, deverá caminhar no sentido da decrescente rigidez organizacional e da crescente flexibilidade (conferindo maior possibilidade de escolha do que se quer aprender) nunca abdicando das necessárias condições uniformizadas de certificação, que se constituem uma condição indispensável para o reconhecimento académico, profissional e social da formação recebida e/ou construída na Universidade. A presente comunicação pretende dar um contributo para a necessária reflexão que urge fazer sobre a missão da Universidade dos nossos dias.

Obtenção de uma porcelana dielétrica a partir de matérias-primas do Rio Grande do Norte

The dielectric porcelain is usually obtained by mixing various raw materials proportions and is used in the production of electronic equipment for various applications, from capacitors of high and low Power to insulators for low, medium, high and extra high voltage, which are used in distribution lines and transmission of electricity.This work was directed to the s tudy of technological properties of technic porcelain, made from raw materials extracted from pegmatites found in the regions of Seridó and the Alto Oeste of Rio Grande do Norte, which are made of kaolin, quartz and feldspar, abundant and high quality in these regions. The technic ceramics were obtained by mixing in appropriate levels, kaolin, feldspar, quartz and clay, the last item from a pottery in the city of Sao Gonçalo do Amarante, Rio Grande do Norte. During the development the following characterizations correlated to raw materials were made: laser particle sizing, x-ray diffraction, DTA and TG. The compositions studied were formed by uniaxial pressing at a pressure of 50 MPa and sintered at temperatures ranging from 1150 to 1350ºC and levels (times) of sintering between 30, 60, 90 and 120 minutes. The characterization of the samples were taken from the analysis of weight loss, linear shrinkage, porosity, stoneware curve, bulk density, flexural strength of three points, SEM and X-ray diffraction, TMA, Dielectric and cross Resistivity. The studied materials can be employed in producing the objects used in electrical engineering such as: insulators for low, medium and high-voltage electrical systems, command devices, bushing insulation for transformers, power capacitors, spark plugs, receptacles for fluorescent and incandescent light bulbs and others

Fabricación y caracterización físico-mecánica de biocomposites reforzados con fibras naturales. Aplicaciones en el sector náutico.

156 p.

A doença de Parkinson e as suas implicações na saúde oral

Dissertação para obtenção do grau de Mestre no Instituto Superior de Ciências da Saúde Egas Moniz

Simulador radiográfico antropomórfico de mama humana

Mammography is a diagnostic imaging method in which interpretation depends on knowledge of radiological aspects as well as the clinical exam and pathophysiology of breast diseases. In this work a mammography phantom was developed to be used for training in the operation of mammographic x-ray equipment, image quality evaluation, self-examination and clinical examination of palpation. Polyurethane was used for the production of the phantoms for its physical and chemical properties and because it is one of the components normally used in prostheses. According to the range of flexibility of the polyurethane, it was possible to simulate breasts with higher or lower amount of adipose tissue. Pathologies such as areolar necrosis and tissue rejection due to surgery reconstruction after partial mastectomy were also simulated. Calcifications and nodules were simulated using the following materials: polyethylene, poly (methyl methacrylate), polyamide, polyurethane and poly (dimethyl silicone). Among these, polyethylene was able to simulate characteristics of calcification as well as breast nodules. The results from mammographic techniques used in this paper for the evaluation of the phantoms are in agreement with data found in the literature. The image analyses of four phantoms indicated significant similarities with the human skin texture and the female breast parenchyma. It was possible to detect in the radiographic images produced regions of high and low radiographic optical density, which are characteristic of breasts with regions of different amount of adipose tissue. The stiffnesses of breast phantoms were adjusted according to the formulation of the polyurethane which enabled the production of phantoms with distinct radiographic features and texture similar to human female breast parenchyma. Clinical palpation exam of the phantoms developed in this work indicated characteristics similar to human breast in skin texture, areolar region and parenchyma

Design gráfico alternativo

Dissertação de Mestrado para obtenção do grau de Mestre em Design de Comunicação, apresentada na Universidade de Lisboa - Faculdade de Arquitectura

The use of subclinical vascular markers of atherosclerosis in youth

The foundations for cardiovascular disease (CVD) in adults are laid in childhood and accelerated by the presence of comorbid conditions. Early detection of manifestations of cardiovascular pathology is an important clinical objective to identify those at risk for subsequent cardiovascular morbidity and events, and to initiate behavioral and medical interventions to reduce risk. Children were once considered to be at low risk, but with the growing health concerns related to lifestyle, cardiovascular screening may be needed earlier. Several noninvasive procedures are available to assess the cumulative effect of these exposures. These include carotid ultrasound, flow-mediated dilation, pulse wave velocity and measures left ventricular mass. This dissertation analyzes the comorbid conditions that increase cardiovascular risk in youth, namely obesity and low physical fitness, using carotid intima-media thickness to objectively detect early manifestations of cardiovascular pathology. Until recently researchers have not used surrogate markers of subclinical atherosclerosis to examine the role of a single bout of exercise. Utilizing the acute exercise model can be advantageous as it allows for an efficient manipulation of exercise variables and permits greater experimental control of confounding variables. It is possible that the effects of a bout of exercise can predict the effects of chronic exercise. We analyze the physiological factors pertinent to arterial stiffness using arterial distensibility and pulse wave velocity in the context of acute exercise in children and adults. In some instances, those who amend their trajectory by not maintaining risk factors into adulthood experience reductions in subclinical markers to levels associated with never having had the risk factor. Though avoidance of risk factors in youth is ideal, there is still a window for intervention where long-lasting cardiovascular effects might be avoided. In this dissertation we present preliminary findings linking modifiable youth risk factors to subclinical markers of CVD in adulthood.

Novos sentidos da leitura: a contribuição do cinema para a leitura do texto narrativo

Mestrado em Literatura Comparada, Faculdade de Ciências Humanas e Sociais, Departamento de Letras Clássicas e Modernas, Univ. do Algarve, 2004

Fachada flexível para casa padronizada em condomínios

The employment of flexibility in the design of façades makes them adaptable to adverse weather conditions, resulting in both minimization of environmental discomfort and improvement of energy efficiency. The present study highlights the potential of flexible façades as a resource to reduce rigidity and form repetition, which are usually employed in condominiums of standardized houses; as such, the work presented herein contributes to field of study of architectural projects strategies for adapting and integrating buildings within the local climate context. Two façade options were designed using as reference the bionics and the kinetics, as well as their applications to architectural constructions. This resulted in two lightweight and dynamic structures, which cater to constraints of comfort through combinations of movements, which control the impact of solar radiation and of cooling in the environment. The efficacy and technical functionality of the façades were tested with comfort analysis and graphic computation software, as well as with physical models. Thus, the current research contributes to the improvement of architectural solutions aimed at using passive energy strategies in order to offer both better quality for the users and for the sustainability of the planet