988 resultados para welding procedure test


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The development of novel strengthening techniques to address the seismic vulnerability of masonry elements is gradually leading to simpler, faster and more effective strengthening strategies. In particular, the use of fabric reinforced cementitious matrix systems is considered of great potential, given the increase of ductility achieved with simple and economic strengthening procedures. To assess the effectiveness of these strengthening systems, and considering that the seismic action is involved, one important component of the structural behaviour is the in-plane cyclic response. In this work is discussed the applicability of the diagonal tensile test for the assessment of the cyclic response of strengthened masonry. The results obtained allowed to assess the contribution of the strengthening system to the increase of the load carrying capacity of masonry elements, as well as to evaluate the damage evolution and the stiffness degradation mechanisms developing under cyclic loading.

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Within the civil engineering field, the use of the Finite Element Method has acquired a significant importance, since numerical simulations have been employed in a broad field, which encloses the design, analysis and prediction of the structural behaviour of constructions and infrastructures. Nevertheless, these mathematical simulations can only be useful if all the mechanical properties of the materials, boundary conditions and damages are properly modelled. Therefore, it is required not only experimental data (static and/or dynamic tests) to provide references parameters, but also robust calibration methods able to model damage or other special structural conditions. The present paper addresses the model calibration of a footbridge bridge tested with static loads and ambient vibrations. Damage assessment was also carried out based on a hybrid numerical procedure, which combines discrete damage functions with sets of piecewise linear damage functions. Results from the model calibration shows that the model reproduces with good accuracy the experimental behaviour of the bridge.

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Despite the extensive research that has been conducted on the debonding behaviour of FRP strengthening systems, no standard methodology has been yet established on its experimental characterization. In this context, to assess the performance and reliability of small scale testing on NSM (near surface mounted) FRP strengthening systems, an experimental program was carried out on a series of nine NSM FRP strengthening systems, in the framework of an international Round Robin Testing (RRT). Eleven laboratories and seven manufacturers and suppliers participated in this extensive international exercise, which regarded both NSM and EBR FRP strengthening systems. Test results obtained for the NSM systems by the participating laboratories are discussed and compared in this paper to investigate the feasibility of the adopted single/double pulling shear test method, to investigate the mechanism of bond between NSM FRP reinforcement and concrete, and to investigate the level of variability obtained between the participating laboratories testing the same material batches. It is concluded that the tested variants in the adopted single/double shear pulling test have a significant influence, stressing the importance of the level of detail of standardized test protocols for bond verification. On overall, given the variants included in this study, the obtained variation in bond stress-slip behaviour between the laboratories remained fairly limited.

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Polymer binder modification with inorganic nanomaterials (NM) could be a potential and efficient solution to control matrix flammability of polymer concrete (PC) materials without sacrificing other important properties. Occupational exposures can occur all along the life cycle of a NM and “nanoproducts” from research through scale-up, product development, manufacturing, and end of life. The main objective of the present study is to analyse and compare different qualitative risk assessment methods during the production of polymer mortars (PM) with NM. The laboratory scale production process was divided in 3 main phases (pre-production, production and post-production), which allow testing the assessment methods in different situations. The risk assessment involved in the manufacturing process of PM was made by using the qualitative analyses based on: French Agency for Food, Environmental and Occupational Health & Safety method (ANSES); Control Banding Nanotool (CB Nanotool); Ecole Polytechnique Fédérale de Lausanne method (EPFL); Guidance working safely with nanomaterials and nanoproducts (GWSNN); Istituto Superiore per la Prevenzione e la Sicurezza del Lavoro, Italy method (ISPESL); Precautionary Matrix for Synthetic Nanomaterials (PMSN); and Stoffenmanager Nano. It was verified that the different methods applied also produce different final results. In phases 1 and 3 the risk assessment tends to be classified as medium-high risk, while for phase 2 the more common result is medium level. It is necessary to improve the use of qualitative methods by defining narrow criteria for the methods selection for each assessed situation, bearing in mind that the uncertainties are also a relevant factor when dealing with the risk related to nanotechnologies field.

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IP networks are currently the major communication infrastructure used by an increasing number of applications and heterogeneous services, including voice services. In this context, the Session Initiation Protocol (SIP) is a signaling protocol widely used for controlling multimedia communication sessions such as voice or video calls over IP networks, thus performing vital functions in an extensive set of public and enter- prise solutions. However, the SIP protocol dissemination also entails some challenges, such as the complexity associated with the testing/validation processes of IMS/SIP networks. As a consequence, manual IMS/SIP testing solutions are inherently costly and time consuming tasks, being crucial to develop automated approaches in this specific area. In this perspective, this article presents an experimental approach for automated testing/validation of SIP scenarios in IMS networks. For that purpose, an automation framework is proposed allowing to replicate the configuration of SIP equipment from the pro- duction network and submit such equipment to a battery of tests in the testing network. The proposed solution allows to drastically reduce the test and validation times when compared with traditional manual approaches, also allowing to enhance testing reliability and coverage. The automation framework comprises of some freely available tools which are conveniently integrated with other specific modules implemented within the context of this work. In order to illustrate the advantages of the proposed automated framework, a real case study taken from a PT Inovação customer is presented comparing the time required to perform a manual SIP testing approach with the one time required when using the proposed auto- mated framework. The presented results clearly corroborate the advantages of using the presented framework.

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Relatório de atividade profissional de mestrado em Direito Judiciário

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Construction of hydroelectric dams in tropical regions has been contributing significantly to forest fragmentation. Alterations at edges of forest fragments impact plant communities that suffer increases in tree damage and dead, and decreases in seedling recruitment. This study aimed to test the core-area model in a fragmented landscape caused by construction of a hydroelectric power plant in the Brazilian Amazon. We studied variations in forest structure between the margin and interiors of 17 islands of 8-100 hectares in the Tucuruí dam reservoir, in two plots (30 and >100m from the margin) per island. Mean tree density, basal area, seedling density and forest cover did not significantly differ between marginal and interior island plots. Also, no significant differences were found in liana density, dead tree or damage for margin and interior plots. The peculiar topographic conditions associated with the matrix habitat and shapes of the island seem to extend edge effects to the islands' centers independently of the island size, giving the interior similar physical microclimatic conditions as at the edges. We propose a protocol for assessing the ecological impacts of edge effects in fragments of natural habitat surrounded by induced (artificial) edges. The protocol involves three steps: (1) identification of focal taxa of particular conservation or management interest, (2) measurement of an "edge function" that describes the response of these taxa to induced edges, and (3) use of a "Core-Area Model" to extrapolate edge function parameters to existing or novel situations.

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Dissertação de mestrado integrado em Mechanical Engineering

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Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Engenharia Clínica)

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The research aimed to establish tyre-road noise models by using a Data Mining approach that allowed to build a predictive model and assess the importance of the tested input variables. The data modelling took into account three learning algorithms and three metrics to define the best predictive model. The variables tested included basic properties of pavement surfaces, macrotexture, megatexture, and uneven- ness and, for the first time, damping. Also, the importance of those variables was measured by using a sensitivity analysis procedure. Two types of models were set: one with basic variables and another with complex variables, such as megatexture and damping, all as a function of vehicles speed. More detailed models were additionally set by the speed level. As a result, several models with very good tyre-road noise predictive capacity were achieved. The most relevant variables were Speed, Temperature, Aggregate size, Mean Profile Depth, and Damping, which had the highest importance, even though influenced by speed. Megatexture and IRI had the lowest importance. The applicability of the models developed in this work is relevant for trucks tyre-noise prediction, represented by the AVON V4 test tyre, at the early stage of road pavements use. Therefore, the obtained models are highly useful for the design of pavements and for noise prediction by road authorities and contractors.

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Nowadays, considering the high variety of construction products, adequate material selection, based on their properties and function, becomes increasingly important. In this research, a ranking procedure developed by Czarnecki and Lukowski is applied in mortars with incorporation of phase change materials (PCM). The ranking procedure transforms experimental results of properties into one numerical value. The products can be classified according to their individual properties or even an optimized combination of different properties. The main purpose of this study was the ranking of mortars with incorporation of different contents of PCM based in different binders. Aerial lime, hydraulic lime, gypsum and cement were the binders studied. For each binder, three different mortars were developed. Reference mortars, mortars with incorporation of 40% of PCM and mortars with incorporation of 40% of PCM and 1% of fibers, were tested. Results show that the incorporation of PCM in mortars changes their global performance.

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Tese de Doutoramento em Psicologia (Especialidade de Psicologia Experimental e Ciências Cognitivas)

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OBJETIVO: O presente estudo teve como objetivo conhecer evidências de validade e precisão do Alcohol Use Disorder Identification Test (AUDIT). MÉTODOS: Contou-se com uma amostra de conveniência (não probabilística) de 547 estudantes universitários de Fortaleza (CE), com idade média de 21,6 anos (dp = 4,86; amplitude de 18 a 53), a maioria do sexo masculino (51,5%), solteira (91,4%) e católica (62,5%). Os participantes responderam ao AUDIT e a perguntas demográficas. Procurando conhecer a estrutura fatorial, além de estatísticas descritivas, realizou-se uma Análise de Componentes Principais. Adicionalmente, a fim de avaliar a precisão do instrumento, efetuaram-se cálculos de alfa de Cronbach (consistência interna), correlações de r de Pearson e coeficiente de correlação intraclasse - ICC (precisão teste-reteste). RESULTADOS: De acordo com a análise de componentes principais com rotação oblimin, a estrutura bifatorial do AUDIT mostrou-se coerente, com todos os itens apresentando saturações satisfatórias, superior a |0,40|, tendo o Fator 1 explicado 47,5% da variância total com alfa de 0,84 e o Fator 2 explicado 11,6% da variância total com alfa de 0,69. Os resultados do teste-reteste indicaram correlação forte entre os dados obtidos na primeira (t1) e segunda (t2) aplicação (r tt = 0,94, p < 0,01), sem diferença significativa de médias nos dois tempos (m t1 = 0,37, dp = 0,49; m t2 = 0,34, dp2= 0,47; p > 0,05), com ICC satisfatório (0,96). CONCLUSÕES: Os achados apoiaram a adequação psicométrica do AUDIT, com as análises fatoriais exploratórias apontando como mais satisfatória a estrutura com dois fatores, bem como atestaram sua boa estabilidade temporal.