Estudo e optimização do acabamento de orlas em tampos de mesa escolares

Tese de mestrado integrado. Engenharia Química. Faculdade de Engenharia. Universidade do Porto. 201

The impact of the Brexit vote on financial narratives : evidence from UK

Estudamos o impacto do referendo do Brexit em empresas transacionadas na London Stock Exchange (LSE) através da análise de mudanças de certa características das suas narrativas financeiras nomeadamente, o tom, a incerteza, o forward–looking e a causalidade. Usando vários modelos de regressão linear, realizamos uma análise das características referidas a diferentes secções do relatório de gestão (Management Discussion and Analysis – MD&A –, mensagem do Chairman e mensagem do CEO). Enquanto o tom não é explicado pelo referendo, as palavras de incerteza, de forward-looking e de causalidade tornam-se mais frequentes após o voto. Os resultados mostram que as empresas reagiram ao referendo do Brexit e alteraram o seu discurso em consequência do resultado do voto.We study the impact of the Brexit referendum on firms listed on the London Stock Exchange (LSE) by analysing the changes in some characteristics of their financial narratives, namely, tone, uncertainty, forward–looking and causal language. Using a multivariate model, we analyse these features on different sections of the management report (e.g. Management Discussion and Analysis, Chairman message and CEO message). While tone is not explained by the referendum, uncertainty, forward-looking and causal words become more frequent after the vote. Our results confirm companies reacted to the Brexit referendum and change their discourse as a consequence of the vote outcome

EVALUATION OF VARIOUS WAVE ENERGY CONVERTERS IN THE BAY OF CÁDIZ

The Andalusian Agency of Energy has identified three areas of major interest for harnessing wave energy, in their plan of “Marine Energy and Energy Resources of Andalusia”. One of these areas is located on the Atlantic coast, the bay of Cádiz. Considering this initial interest, the objective of this work is to carry out an evaluation of the performance provided by various technologies of wave energy conversion in the bay of Cádiz. The data for the wave climate in the target area are obtained from the Spanish Agency Puertos del Estado. Diagrams for bivariate distributions of the sea states occurrences, defined by the significant wave height and the energy period, are shown. On this basis, the output of nine different technologies for the conversion of wave energy is assessed in the reference locations in the bay of Cádiz. According to the results obtained, it can be said that the bay of Cádiz is a suitable place for wave energy extraction

3D Simulation of Ship Motions to Support the Planning of Rescue Operations on Damaged Ships

AbstractThe paper describes a software system to simulate the ship motions in a crisis situation. The scenario consists of a damaged ship subjected to wave excitation forces generated by a random sea state. The simulation is displayed in an interactive Virtual Environment allowing the visualization of the ship motions. The numerical simulation of the sea surface and ship motions requires intensive computation to maintain the real-time or even the fast-forward simulations, which are the only ones of interest for these situations. Dedicated tools to analyse the ship behaviour in time are also described. The system can be useful to evaluate the responses of the ship to the current sea state, namely the amplitude, variations and tendencies of ship motions, and help the planning and coordination of rescue operations

OVERVIEW AND PROSPECTS FOR DEVELOPMENT OF WAVE AND OFFSHORE WIND ENERGY

An overview of the present state of development of offshore renewable wave and wind energy is presented and future prospects are discussed. The information on some of the current wave energy systems worldwide are given as indicative of the present state of affairs. The main working principles of wave energy systems are described and the differences in terms of working principle, conversion chain, location and power take-off systems are highlighted. Some of the technology challenges are identified and the prospects of utilization of the various wave energy concepts are discussed comparing the characteristics of the devices in particular their power output. The evolution of the concepts of wind turbines with time and the main types of offshore wind turbine concepts are presented, from the shallow water fixed ones to the floating ones. The development of various numerical codes for the dynamic analysis of offshore wind turbines and the studies carried out based on the codes for hydrodynamic, aerodynamic, structural and response due to control system are presented. The present status of wind energy compared to wave energy and the role of naval architects and ocean engineers for the design and analysis of wave energy device and offshore wind turbine technology are presented and discussed

Stress concentration factors in FRP-reinforced tubular DKT joints under axial loads

The stress concentration factors (SCFs) in uniplanar fibre-reinforced polymer (FRP) DKT joints are calculated under five axial loading conditions to determine the maximum SCFs. To this end, 108 finite element models of reinforced DKT joints with different FRPs and geometrical parameters are analysed. Available experimental data and formulas are used to validate the finite element models. The validated finite element models are utilized to investigate the effects of the FRP parameters along with different geometrical parameters on the stress concentration factors in uniplanar DKT joints. The simulations show a reduction of the maximum SCF by around 40% compared to unreinforced DKT joints. The reduction effect increases significantly with increasing the FRP thickness and the number of layers. Despite the notable efficacy of the FRP sheets on the drop of the SCFs in the X-connections, there is not any study or equation on the X-joints with FRP. Therefore, a precise equation is proposed for quantifying the SCFs in X-connections with FRP and is checked against the UK DoE acceptance standard

Methodology to Calculate the Costs of a Floating Offshore Renewable Energy Farm

This paper establishes a general methodology to calculate the life-cycle cost of floating offshore renewable energy devices, applying it to wave energy and wind energy devices. It is accounts for the contributions of the six main phases of their life-cycle: concept definition, design and development, manufacturing, installation, exploitation and dismantling, the costs of which have been defined. Moreover, the energy produced is also taken into account to calculate the Levelized Cost of Energy of a floating offshore renewable energy farm. The methodology proposed has been applied to two renewable energy devices: a floating offshore wave energy device and a floating offshore wind energy device. Two locations have been considered: Aguçadoura and São Pedro de Moel, both in Portugal. Results indicate that the most important cost in terms of the life-cycle of a floating offshore renewable energy farm is the exploitation cost, followed by the manufacturing and the installation cost. In addition, the best area in terms of costs is the same independently of the type of floating offshore renewable energy considered: Aguçadoura. However, the results in terms of Levelized Cost of Energy are different: Aguçadoura is better when considering wave energy technology and the São Pedro de Moel region is the best option when considering floating wind energy technology. The method proposed aims to give a direct approach to calculate the main life-cycle cost of a floating offshore renewable energy farm. It helps to assess its feasibility and evaluating the relevant characteristics that influence it the most

Lourenço Filho e a Matemática da Escola Nova

Disponível em:http://aplicacoes.ifs.edu.br/periodicos/index.php/caminhos_da_educacao_matematica/article/download/2/3.O texto analisa o papel de Lourenço Filho para a educação matemática brasileira. Percorre a trajetória desse educador desde as suas primeiras atividades docentes, na década de 1920, onde orienta a modernização do ensino de matemática nos primeiros anos escolares pelas Cartas de Parker. Depois disso, o estudo descreve o impacto da obra Testes ABC no dia-a-dia das escolas e a entrada em cena de um processo de matematização da pedagogia. Por fim, traz a análise de obra didática de Lourenço Filho para o ensino de aritmética revelando a incorporação de novos aportes da psicologia experimental de base estatística na reorganização da matemática escolar para o curso primário