Modelling a cable structure for a new wind energy production device

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Mecânica Especialização em Concepção e ProduçãoThe following thesis subject is based on the identification and dimensioning of the main mechanical components of the ground station of Boreas prototype, as well as a three-dimensional finite element analysis of structural cable that connects the ground station to the module's air system. The module powered by a lift force pulls a cable that drives a mechanical system which in turn drives a generator during the productive phase of the energy cycle. In the other phase, the system inverts the turn and energy is consumed. The production of energy should be greater than the energy consume. The dimensioning of main mechanical components of ground station includes: flywheel, cable, capstan drum and winder drum. Structural analysis of the cable is performed with an algorithm based on a three-dimensional finite element analysis, which allows the control of cable tension on the end of capstan, prevent the rupture of cable, avoid high forces on bearings and the shock between the rope and the ground. The results of programme developed with the algorithm, are compared with the results obtained by an analytical approach and with commercial software of finite elements. This thesis contributes to the realization of mechanical components included in the prototype

Análise dos factores preditores de sucesso na natação absoluta, em Portugal

Dissertação de mestrado em Treino Desportivo de Crianças e Jovens, apresentada à Faculdade de Ciências do Desporto e Educação Física da Universidade de CoimbraO estudo teve como base os dados recolhidos entre 1999 e 2005 em atletas portugueses filiados na Federação Portuguesa de Natação com o objectivo de identificar nesse período de avaliação dos factores determinantes para alcançar o topo nacional nos dois ciclos olímpicos seguintes. A amostra é constituída por 35 indivíduos do sexo masculino e 178 do sexo feminino com idades entre os 11 e os 16 anos (Rapazes - média 14,95±0,88; Raparigas – média 13,05±0,76) e analisaram-se aspectos como: idade, idade óssea, rácio idade óssea / idade cronológica, volume de treino por unidade, pontos LEN, Massa, Estatura, Altura Sentado, Índice Morfo – Dinâmico, Comprimento do Membro Inferior, Comprimento do Membro Superior, Somatório de Pregas, Flexão do Ombro, Flexão do Tronco, Preensão Máxima, Força Máxima da Adução do Ombro e Força Máxima da Rotação Interna do Ombro Máxima, Flutuabilidade Horizontal e Vertical, Deslize, Deslize Após Salto, Velocidade Máxima a Livres e a Bruços, Velocidade Média no T30, Frequência Gestual Média do T30 e Índice de Nado no T30; associados ao critério deentrada ou não no TOP 10 nacional entre as épocas de 2003/2004 e 2011/2012. Verificou-se a existência de diferenças em ambos os sexos entre os grupos que atingiram e não atingiram o TOP 10 nacional nos seguintes aspectos: idade, pontos LEN, Velocidade Máxima a Livres e a Bruços, Velocidade Média no T30, Frequência Gestual Média do T30 e Flutuabilidade Horizontal. Este estudo permite indiciar que , os programas de acompanhamento de talentos poderão adotar um número reduzido de protocolos de avaliação ganhando em economia e operacionalidade. É possível ainda concluir que a possibilidade de predição para atingir o alto rendimento em NPD nestas idades parece estar associada sobretudo a variáveis estreitamente relacionadas com o processo de treino This study was based on data collected between 1999 and 2005 in Portuguese athletes participating in training champs. The goal was to identify the physical traits and factors that allow athletes to get to high levels off performance. The sample was composed by 35 boys and 178 girls aged between 11 and 16 years old (boys 14,95±0,88; girls 13,05±0,76) and aspects such as: age, skeletal maturation, skeletal maturation/chronologic age ratio, training volume per unit, LEN points, body mass, stature, seated height, morfo-dinamic index, leg length, arm length, skinfolds, shoulder flexion, torso flexion, maximal handgrip strength, vertical and horizontal buoyancy , 30-minute continuum swim test average velocity and average stroke rate, maximal glide distance, maximal velocity in freestyle and breaststroke, and achievement or not of the TOP10 national ranking in seasons from 2003/2004 to 2011/2012, were analysed. Differences were verified, in both genders, between the groups that get to the TOP10 and those who didn’t in several aspects as: age, LEN points, maximal velocity in freestyle and breaststroke, 30-minute swim test average velocity and average stroke rate and horizontal floating. Above all it seems that, probably, talent identification programs at these ages, should employ less protocols and be less expensive, because few variables can be used to predict success and most of them are related to de training process

Analysis of electrical drive speed control limitations of a power take-off system for wave energy converters

The active control of wave energy converters with oil-hydraulic power take-off systems presents important demands on the electrical drives attached to their pumps, in particular on the required drive accelerations and rotational speeds. This work analyzes these demands on the drives and designs reliable control approaches for such drives by simulating a wave-to-wire model in a hardware in-the-loop simulation test rig. The model is based on a point absorber wave energy converter, being the wave, hydrodynamic and oil-hydraulic part simulated in a computer that sends and receives signals from the real embedded components, such as the drive generator, controller and back-to-back converter. Three different control strategies are developed and tested in this test rig and the results revealed that despite the drive limitations to acceleration levels, well above 1 × 104 rpm/s, these do not significantly affect the power take-off efficiency, because the required acceleration peaks rarely achieve these values. Moreover this drive is much more economical than an oil-hydraulic and equivalent one that is able to operate at those peaks of acceleration.This work was performed within the Strategic Research Plan of the Center for Marine Technology and Ocean Engineering, which is financed by Portuguese Foundation for Science and Technology (Fundacao para a Ciencia e Tecnologia-FCT) and the project "Generic hydraulic power take-off system for wave energy converters" funded by the Portuguese Foundation for Science and Technology (FCT) under contract PTDC/EMS-SIS-1145/2014. The testing has received support from MARINET, a European Community - Research Infrastructure Action under the FP7 "Capacities" Specific Programme, grant agreement nr. 262552. The research leading to these results is also part of the OceaNET project, which has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement nr. 607656

Projeto de animação e intervenção : cinema de rua

Trabalho de Projeto apresentado à Escola Superior de Educação do Instituto Politécnico de Castelo Branco para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Animação Artística.O presente trabalho pretende configurar-se como um trabalho de intervenção aplicada ao desenho, construção e aplicação de um projeto de animação no âmbito do desenvolvimento local, cultural, comunitário. Partindo de uma análise diagnóstica com o intuito principal de fazer um levantamento das carências e das potencialidades culturais existentes na Freguesia de Aldeia de João Pires, concelho de Penamacor, o projeto, define, de seguida, quais as atividades que podem melhor adequar-se a esse contexto territorial enquanto promotoras de um desenvolvimento comunitário assente na promoção de valores culturais locais. O projeto pretendeu criar sessões de Cinema de Rua na Aldeia de João Pires e teve como objetivo principal o desenvolvimento cultural e local desta comunidade beirã demograficamente envelhecida, bem como o de proporcionar dias diferentes, criando uma relação de proximidade entre as associações locais com a comunidade, ajudando desta forma no combate ao isolamento social.The present work intends to set yourself up as an intervention work applied to the design, construction and implementation of an animation project in the context of local cultural, community, development. Starting from a diagnostic analysis with the main aim to make an assessment of needs and of existing cultural potential in the Aldeia de João Pires, Penamacor, design, sets, then, what are the activities that can best suit this territorial context while promoting a community development based on the promotion of local and cultural values. The project intended to create cinema in street, in the Aldeia de João Pires and had as main objective the cultural and local development of this community built demographically aging, as well as to provide different days, creating a close relationship between the local associations with the community, helping in this way in combating social isolation

Experimental analysis of wave energy converters concentrically attached on a floating offshore platform

This paper presents an initial experimental study of wave energy converters concentrically arranged and attached on a floating offshore platform model. The 1:27 scale model, has been designed, built and tested, in two main situations, without and with twelve cone shape wave energy converters. To simulate the power take-off system in each wave energy converter, rotational friction dampers have been installed on the joints of the floaters arms to the platform deck. The experimental results show that the interaction between buoys and platform have a positive effect on the platform heave and pitch motions. However, the reduction in heave and pitch motions of the platform, after installing the wave energy converter array, depends on the damping of the equivalent power take-off system. Thus, the effect of dampers in the motion of buoys is presented to allow an initial understanding of the required damping range of the power take-off system and related control strategies.info:eu-repo/semantics/publishedVersio

Numerical and experimental analysis of a hybrid wind-wave offshore floating platform’s hull

This paper presents a study regarding a novel hybrid concept for both wind and wave energy offshore. The concept resembles a semi-submersible wind platform with a larger number of columns. Wave Energy Devices such as point absorbers are to be displayed around the unit, capturing wave energy while heaving and also enhancing the stability of the platform. In this paper, a first numerical study of the platform’s hull, without Wave Energy Converters, is carried out. Experiments in wave basin regarding the same unit have been conducted and the results are presented and compared to the numerical ones. Both stability and seakeeping performances are assessed and compared.info:eu-repo/semantics/publishedVersio

On the experimental study of a concentric wave energy array adapted to an offshore floating platform

Experimental results of the dynamics of a small scale concentric wave energy converter array adapted to a floating offshore platform are presented. A small scale prototype is tested without and with twelve conical heaving point absorbers. The free decay and regular wave tests are carried out in an ocean basin to understand the hydrodynamic interactions between various elements of the floating offshore platform and wave energy converter array. Meanwhile, the heave motions of the buoys are observed in regular waves with and without dampers for the initial estimation of power take-off damping as a pitch control module. The results show the improvements in heave, pitch, and roll performance of the platform due to the interaction between the buoys and platform.info:eu-repo/semantics/publishedVersio