Experimental analysis of the cyclic response of traditional timber joints and their influence on the seismic capacity of timber frame structures

Timber connections represent the crucial part of a timber structure and a great variability exists in terms of types of connections and mechanisms. Taking as case study the widespread traditional timber frame structures, in particular the Portuguese Pombalino buildings, one of the most common timber connection is the half-lap joint. Connections play a major role in the overall behaviour of a structure, particularly when assessing their seismic response, since damage is concentrated at the connections. For this reason, an experimental campaign was designed and distinct types of tests were carried out on traditional half-lap joints to assess their in-plane response. In particular, pull-out and in-plane cyclic tests were carried out on real scale unreinforced connections. Subsequently, the connections were retrofitted, using strengthening techniques such as self-tapping screws, steel plates and GFRP sheets. The tests chosen were meant to capture the hysteretic behaviour and dissipative capacity of the connections and characterise their response and, therefore, their influence on the seismic response of timber frame walls, particularly concerning their uplifting and rotation capacity, that could lead to rocking in the walls. In this paper, the results of the experimental campaign are presented in terms of hysteretic curves, dissipated energy and equivalent viscous damping ratio. Moreover, recommendations are provided on the most appropriate retrofitting solutions.

Companies' OHS internal structures: Types and theoretical foundations

An organization manages to regulate, standardize and optimize its operations in a way that places health and safety first by considering Health, Safety, Environment and Ergonomics (HSEE). In order to provide a theoretical foundation for Companies’ Occupational Health and Safety Internal Structures (COHSIS) allowing the focus on safety, COHSIS and its fundamentals were reviewed and described based on a brief literature review, which have included both papers published in journals, as well as works made available by selected organizations with mature safety culture. Three COHSIS were defined for description of its fundamentals, enabling improve the usability of its terminologies and provide the mentioned theoretical foundation.

Fractional pennes' bioheat equation: theoretical and numerical studies

In this work we provide a new mathematical model for the Pennes’ bioheat equation, assuming a fractional time derivative of single order. Alternative versions of the bioheat equation are studied and discussed, to take into account the temperature-dependent variability in the tissue perfusion, and both finite and infinite speed of heat propagation. The proposed bioheat model is solved numerically using an implicit finite difference scheme that we prove to be convergent and stable. The numerical method proposed can be applied to general reaction diffusion equations, with a variable diffusion coefficient. The results obtained with the single order fractional model, are compared with the original models that use classical derivatives.

Adult learning and education policies in Germany, Portugal and Sweden: An analysis of national reports to CONFINTEA VI

The chapter presents a theoretical proposal of three analytical models of Adult Learning and Education (ALE) policies. Some analytical categories and the corresponding dimensions are organised according to the ALE rationale which is typical of each social policy model. Historical, cultural and educational features are mentioned in connexion with the different policy models and its interpretative capacity to making sense of policies and practices implemented in Germany, Portugal and Sweden. !e analysis includes the states of the art and the official representations of ALE produced by the respective national authorities through national reports which were presented to CONFINTEA VI (2009).

Modeling separator membranes physical characteristics for optimized lithium ion battery performance

The effect of varying separator membrane physical parameters such as degree of porosity, tortuosity and thickness, on battery delivered capacity was studied in order to optimize performance of lithium-ion batteries. This was achieved by a theoretical mathematical model relating the Bruggeman coefficient with the degree of porosity and tortuosity. The inclusion of the separator membrane in the simulation model of the battery system does not affect the delivered capacity of the battery. The ionic conductivity of the separator and consequently the delivered capacity values obtained at different discharge rates depends on the value of the Bruggeman coefficient, which is related with the degree of porosity and tortuosity of the membrane. Independently of scan rate, the optimal value of the degree of porosity is above 50% and the separator thickness should range between 1 μm at 32 μm for improved battery performance.

Lithium ion rechargeable batteries: State of the art and future needs of microscopic theoretical models and simulations

This review deals with the recent developments and present status of the theoretical models for the simulation of the performance of lithium ion batteries. Preceded by a description of the main materials used for each of the components of a battery -anode, cathode and separator- and how material characteristics affect battery performance, a description of the main theoretical models describing the operation and performance of a battery are presented. The influence of the most relevant parameters of the models, such as boundary conditions, geometry and material characteristics are discussed. Finally, suggestions for future work are proposed.

Modelo de conhecimento para intermediários de inovação com Crowdsourcing

Tese de Doutoramento em Tecnologias e Sistemas de Informação.

Implementação de um novo processo produtivo adequado à introdução faseada de múltiplos produtos

Dissertação de mestrado integrado em Engenharia e Gestão Industrial

Sustainability assessment of envelope wall solutions using MAXergy methodology

Projeto de investigação integrado de International Master in Sustainable Built Environment

High performance screen printable lithium-ion battery cathode ink based on C-LiFePO4

Lithium-ion battery cathodes have been fabricated by screen-printing through the development of CLiFePO4 inks. It is shown that shear thinning polymer solutions in N-methyl-2-pyrrolidone (NMP) with Newtonian viscosity above 0.4 Pa s are the best binders for formulating a cathode paste with satisfactory film forming properties. The paste shows an elasticity of the order of 500 Pa and, after shear yielding, shows an apparent viscosity of the order of 3 Pa s for shear rates corresponding to those used during screen-printing. The screen-printed cathode produced with a thickness of 26 mm shows a homogeneous distribution of the active material, conductive additive and polymer binder. The total resistance and diffusion coefficient of the cathode are 450 V and 2.5 10 16cm2 s 1, respectively. The developed cathodes show an initial discharge capacity of 48.2 mAh g 1 at 5C and a discharge value of 39.8 mAh g 1 after 50 cycles. The capacity retention of 83% represents 23% of the theoretical value (charge and/or discharge process in twenty minutes), demonstrating the good performance of the battery. Thus, the developed C-LiFePO4 based inks allow to fabricate screen-printed cathodes suitable for printed lithium-ion batteries

Webfólio de aprendizagem: contributos para a promoção da autonomia e reflexividade em estudantes do 12º ano de escolaridade

Relatório de estágio de mestrado em Ensino de Informática

Velhas e novas drogas: impactos da toxicodependência: estudo de caso na cidade de Braga

Dissertação de mestrado em Sociologia (área de especialização em Organizações e Trabalho)

Trabalho cooperativo como finalidade e estratégia de aprendizagem. Um estudo de caso em biologia humana

A aprendizagem cooperativa é concebida como uma estratégia pedagógica que privilegia uma aprendizagem personalizada e que potencia o sucesso educativo não só individual mas também coletivo. É conseguida através da cooperação de todos os membros do grupo, em que o desempenho de cada um influencia e é influenciado pelo desempenho do Outro. O grupo é concebido como uma organização social cuja eficiência implica a capacidade de construção e manutenção do grupo como um todo e de promoção do sucesso educativo de todos os elementos. É este quadro teórico que enforma a conceção, implementação e avaliação de uma intervenção pedagógica em Biologia Humana do 10º ano do Curso Tecnológico de Desporto. A estratégia pedagógica carateriza-se pela operacionalização articulada de estruturas e papéis de cooperação na abordagem da unidade didática - Transformação e Utilização de Energia - com a finalidade de promover a aprendizagem integrada de competências de cooperação e de conhecimento substantivo da área da Biologia. A avaliação da intervenção pedagógica incidiu nos objetivos de investigação - 1) Identificar o impacto da estratégia de intervenção pedagógica no desenvolvimento de competências de cooperação e 2) Identificar o impacto da estratégia de intervenção pedagógica no desenvolvimento de competências disciplinares –, efetuada a partir da análise de tarefas de aprendizagem e de um questionário de avaliação final global aplicado aos alunos. A estratégia de intervenção pedagógica é percecionada pelos alunos como tendo contribuído para a promoção do desenvolvimento não só de competências de cooperação mas também do conhecimento substantivo e do pensamento crítico.