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- Development of a Simulation Tool for Electromagnetism EducationPublication . Auwarter, Bianca; Brandão, Diego; Ferreira, Ângela P.The widespread adoption in the educational system of information and communications technologies allows the use of interactive simulations, able to support a meaningful insight into the fundamental laws and concepts of electromagnetic theory, which, in a classical approach, would require a vector calculus background and three-dimensional geometrical resourcefulness, typically not maturated by the students in undergraduate engineering programmes. The use of simulation tools based on finite element analysis can facilitate the learning process by allowing users to create and/or exploit visual and more accurate models. ONELAB (Open Numerical Engineering LABoratory) is a simulation platform that integrates severalmodelling tools, including Gmsh, a three-dimensionalmesh modelling software. This simulation tool is able to provide interaction, accuracy, and visual interpretations of classical problems using the fundamental laws of electromagnetism. The application with the basic laws of electromagnetism has been developed to run on mobile devices, besides desktops, to improve its ease of access and dissemination.
- A linear regression pattern for electricity price forecasting in the Iberian electricity marketPublication . Ferreira, Ângela P.; Jenice, Ramos; Fernandes, Paula OdeteThe Iberian Market for Electricity resulted from a cooperation process developed by the Portuguese and Spanish administrations, aiming to promote the integration of the electrical systems of both countries. This common market consists of organised markets or power exchanges, and non-organised markets where bilateral over-the-counter trading takes place with or without brokers. Within this scenario, electricity price forecasts have become fundamental to the process of decision-making and strategy development by market participants. The unique characteristics of electricity prices such as non-stationarity, non-linearity and high volatility make this task very difficult. For this reason, instead of a simple time forecast, market participants are more interested in a causal forecast that is essential to estimate the uncertainty involved in the price. This work focuses on modelling the impact of various explanatory variables on the electricity price through a multiple linear regression analysis. The quality of the estimated models obtained validates the use of statistical or causal methods, such as the Multiple Linear Regression Model, as a plausible strategy to achieve causal forecasts of electricity prices in medium and long-term electricity price forecasting. From the evaluation of the electricity price forecasting for Portugal and Spain, in the year of 2017, the mean absolute percentage errors (MAPE) were 9.02% and 12.02%, respectively. In 2018, the MAPE, evaluated for 9 months, for Portugal and Spain equals 7.12% and 6.45%, respectively.
- Sistemas de transmissão baseados em ímãs permanentesPublication . Sousa, Maria Sabrina; Ferreira, Ângela P.; Júnior, Amilton F.Engrenagens são elementos de máquinas utilizadas na transmissão de movimentos rotativos entre eixos. As engrenagens magnéticas, assim como as mecânicas, podem ser aplicadas a qualquer sistema que inclua uma máquina rotativa e uma carga. As engrenagens magnéticas possuem muitas vantagens quando comparadas com as engrenagens convencionais (mecânicas), como, por exemplo, a não necessidade de lubrificação, manutenção reduzida, transmissão de torque sem contato mecânico, não geração de ruídos, além de possuírem uma maior durabilidade e confiabilidade. Todas essas características das engrenagens magnéticas estão associadas ao seu diferencial, que é a utilização de ímãs permanentes em seus rotores e peças de ferro no anel estacionário. As peças de ferro são responsáveis por fazer a modulação do fluxo magnético nos entreferros interno e externo. Esse trabalho é um estudo das propriedades magnéticas de maneira geral, caracterização dos ímãs permanentes (componentes fundamentais das engrenagens magnéticas) e estabelecimento inicial de um projeto analítico de uma engrenagem magnética coaxial com ímãs permanentes de terras raras (NdFeB) recorrendo a uma rede de relutâncias. O projeto analítico envolve o cálculo das relutâncias, das forças magnetomotrizes e fluxo magnético através de uma análise de um passo polar de uma engrenagem magnética coaxial em esquema planar e com um modelo simplificado do seu circuito magnético.
- Measuring technical efficiency of European Countries using data envelopment analysisPublication . Vaz, Clara B.; Ferreira, Ângela P.This study proposes a Data Envelopment Analysis (DEA) framework to assess the technical efficiency of 26 European countries in the last five years, under the ongoing 2020 energy policy. DEA is used to estimate efficiency which is complemented by bootstrapping to obtain statistical inferences. Further, we explore the relationship between the targets regarding energy efficiency, renewable energy share and the greenhouse gas emissions and, in addition, the electricity prices derived from the energy system on the efficiency levels of European countries through a panel data truncated regression with bootstrapping. It is observed that the bias-corrected efficiency of the economies increased approximately 13%, on average, since 2009. The results achieved bring into view that the efforts regarding the energy policies developed in each country to follow 20-20-20 targets, have not threatened the improvement of their efficiency.
- CIEEMAT 2022 - VII Ibero-American Congress on Entrepreneurship, Energy, Environment and Technology: book of abstractsPublication . Ferreira, Ângela P. (Ed.); Fernandes, Carla S. (Ed.); Fernandes, Florbela P. (Ed.); Pais, Luís S. (Ed.)The VII Ibero-American Congress on Entrepreneurship, Energy, Environment and Technology (VII CIEEMAT), coordinated by the Federal Centre of Technological Education from Rio de Janeiro (CEFET/RJ), was held for the third time in Portugal, and for the second time in the city of Bragança, under the organization of the Polytechnic Institute of Bragança (IPB), the Research Centre in Digitalization and Intelligent Robotics (CeDRI), the Mountain Research Centre (CIMO) and the Associated Laboratory for Sustainability and Technology in Inland Regions (SusTEC). The event aims to consolidate the Luso- Brazilian and Ibero-American cooperation in those areas, gathering the multinational contribution and enhancing collaboration in academic and scientific fields. The VII CIEEMAT took place on July 6-8, 2022 and had the Energy Transition as its specific theme. The current energy context and the transition of energy generation and consumption typologies are unavoidable in defining the profiles of national and international societies and energy policies. The dynamism to which the energy sector is currently subjected is imposed by environmental and safety concerns, the fluctuation of the fossil fuels price and shifting technologies, which translates into challenges and opportunities across various sectors as research and innovation, education, policy and environmental governance. The opportunities and challenges of the energy transition are outlined, for instance, in the exploitation of natural assets, the decarbonisation of the economy and the transport sector and the flexibility of energy infrastructure through smart grids. The VII CIEEMAT followed a program addressing various perspectives of action of higher education institutions and R&D units and their cooperation with society: i) the academic perspective (why, what and how to teach the challenges of energy transition); ii) the perspective of international cooperation, defining new cooperation programs between Portugal and Brazil in the energy field, with emphasis on the Brazilian EnergIF program and its potential for international cooperation with Portugal; iii) and the research and innovation perspective, with the contribution of academic experts and the business sector regarding the challenges that the necessary and emerging energy transition poses. At the same time, the VII CIEEMAT provided also a forum to disseminate and share ongoing research in various academic and scientific institutions, through oral communications in the areas of sustainable urban mobility, energy generation and self-consumption, environmental challenges, decarbonisation and climate change.
- I Jornadas Afrociências: livro de resumosPublication . Fernandes, Paula Odete (Ed.); Ferreira, Ângela P. (Ed.); Semedo, Arlinda Suzete Monteiro (Ed.); Dabó, Braima Suncar (Ed.); Scalabrini, E.C.B. (Ed.); Ferreira, Jessica (Ed.); Garcia, Pascoal da Pena Virgílio (Ed.)As I Jornadas AFROCIÊNCIAS, subordinadas ao tema “De onde Viemos, Onde Estamos e para Onde Vamos”, é um evento científico inovador que tem como um dos seus objetivos a disseminação de conhecimento técnico-científico, com ênfase no continente africano, e o intercâmbio de ideias que enriqueçam os participantes e as suas instituições, que resulte no desenvolvimento de projetos conjuntos, gerando impacto científico e contribuição para o crescimento de jovens investigadores. A ideia da realização das I Jornadas AFROCIÊNCIAS nasceu da iniciativa de um grupo de estudantes da Escola Superior de Tecnologia e Gestão (ESTiG) do Instituto Politécnico de Bragança (IPB), nomeadamente, Arlinda Semedo, Braima Dabó e Pascoal Garcia, e foi apadrinhada e acolhida pelo Professor Doutor Orlando Rodrigues (Presidente do IPB), Professor Doutor Nuno Ribeiro (Diretor da ESTiG) e pela Professora Doutora Paula Odete Fernandes (Coordenadora Científica da UNIAG). Diante deste cenário, a Associação dos Estudantes Africanos em Bragança, o Instituto Politécnico de Bragança, a Escola Superior de Tecnologia e Gestão e a Unidade de Investigação Aplicada em Gestão (UNIAG) tiveram a honra de anunciar as I Jornadas AFROCIÊNCIAS que decorreram no período de 23 a 24 de maio de 2024.
- Framework for performance assessment of wind farmsPublication . Vaz, Clara B.; Ferreira, Ângela P.This study develops a framework to provide insights regarding the performance of the farms of an energy player in the Portuguese wind sector. Firstly, the Data Envelopment Analysis is used to measure the efficiency of wind farms in producing electrical energy from the resources available and exogenous variables, during operating stage. This analysis enables the identification of the best practices of the efficient farms which can be emulated by inefficient ones. Secondly, Malmquist index is used to evaluate the changes in wind farms productivity. Bootstrap procedures are applied to obtain statistical inference on the efficiency estimates.
- A panel data analysis of the electric mobility deployment in the Eropean UnionPublication . Gruetzmacher, Sarah; Vaz, Clara B.; Ferreira, Ângela P.This study aims to find and develop an appropriate optimization approach to reduce the time and labor employed throughout a given chemical process and could be decisive for quality management. In this context, this work presents a comparative study of two optimization approaches using real experimental data from the chemical engineering area, reported in a previous study [4].The first approach is based on the traditional response surface method and the second approach combines the response surface method with genetic algorithm and data mining. The main objective is to optimize the surface function based on three variables using hybrid genetic algorithms combined with cluster analysis to reduce the number of experiments and to find the closest value to the optimum within the established restrictions. The proposed strategy has proven to be promising since the optimal value was achieved without going through derivability unlike conventional methods, and fewer experiments were required to find the optimal solution in comparison to the previous work using the traditional response surface method.
- Probabilistic clustering of wind energy conversion systems using classification modelsPublication . Fernandes, Paula Odete; Ferreira, Ângela P.This research intends to give insights on the pattern aggregation of wind energy conversion systems technologies through identification of homogeneous groups within a set of wind farms installed in Portugal. Pattern aggregation is performed using Hierarchical Cluster Analysis followed by Discriminant Analysis, in order to validate the results produced by the first one. The clustering support matrix uses three independent variables: installed capacity, net production and capacity factor, in a per year basis. Cluster labelling allows the identification of two homogenous groups of wind farms, whose main attributes are based on the technological conversion system trend: (1) asynchronous generator based technology and (2) direct driven synchronous generator based technology, with higher capacity factors.
- Projecto de uma máquina de ímanes permanentes de fluxo axial orientado para os sistemas de conversão de energia eólicaPublication . Ferreira, Ângela P.A elevada eficiência volumétrica dos materiais magnéticos permanentes de terras raras, disponíveis, actualmente, a custos acessíveis, possibilita a exploração de novas configurações de máquinas eléctricas e a concretização de factores de escala impraticáveis nos sistemas de excitação, classicamente obtidos através de densidades de correntes, favorecendo a redução das dimensões e, ainda, o rendimento daquelas. No contexto tecnológico actual de produtos eléctricos integrados, as máquinas de ímanes permanentes de fluxo axial apresentam um potencial considerável nas aplicações de baixas velocidades, atendendo às geometrias praticáveis e à superior densidade de binário que as caracteriza. Da análise comparativa da configuração axial com a sua homóloga radial, demonstra-se que a máquina de ímanes permanentes de fluxo axial apresenta uma densidade de binário superior em projectos que utilizem mais de quatro pares de pólos. A geometria particular da configuração da máquina de ímanes permanentes de fluxo axial introduz variáveis que impõem modificações nos processos clássicos de projecto e construção das máquinas eléctricas. Neste trabalho, desenvolve-se uma rotina de projecto da máquina de ímanes permanentes de fluxo axial, com ênfase na configuração de duplo entreferro, rotor interno. A rotina desenvolvida incorpora as interacções electromagnéticas e térmicas, sendo baseada em ferramentas analíticas e de simulação com recurso ao Método dos Elementos Finitos. Foi ainda projectado e construído um protótipo, cujas decisões de projecto foram orientadas para os micro e mini sistemas de conversão de energia eólica. A implementação prática e a sua experimentação laboratorial permitiram validar a exequibilidade do processo construtivo e corroborar as variáveis iniciais definidas no anteprojecto.