Browsing by Issue Date, starting with "2024-12-20"
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- Development of optimized methods to Quality Control GNSS ObservationsPublication . Ventura, Diogo Miguel Rodrigues; Crocker, Paul Andrew; Fernandes, RuiThis report describes the internship carried out at MIRASpaco, focusing on the development of quality control procedures for RINEX files distributed through the MIRAnet software. This software, developed by MIRASpaco, distributes RINEX files to its users. The internship’s primary objective was to implement functionalities enabling GNSS station monitoring through these files. The report begins with an introduction to the company and a detailed description of the internship objectives. It then covers fundamental concepts of the GNSS system, essential for understanding MIRAnet and the work to be done. The document also includes a study on the state of the art in quality control applications for RINEX files, with an analysis of the G-Nut/Anubis software, which was selected for use in this project. Additionally, the report presents a chapter dedicated to software engineering, where system requirements, software architecture, and the database schema necessary for the project’s development are specified. The technologies used are discussed to provide context for the project’s development, which is detailed in the penultimate chapter. Finally, the report concludes that all the objectives set for the internship were successfully achieved, resulting in the implementation of an effective quality control procedure for RINEX files in MIRAnet.
- Uma proposta de treinamento online de Português Língua Não Materna (PLNM)Publication . Lopes, Thiago Cavalcante; Carrilho, Ana Rita de Sousa AguiarEste projeto apresenta o desenvolvimento e a implementação de um treinamento online para o ensino de português como língua não materna (PLNM), com o objetivo de promover a disseminação da língua portuguesa e das culturas brasileira e de outros países lusófonos no contexto global. A proposta utilizou metodologias como a intercompreensão e a abordagem comunicativa, além de combinar atividades síncronas e assíncronas para otimizar o aprendizado. Ferramentas tecnológicas, como a plataforma Hotmart, Google Meet, Telegram e Duocards, foram aplicadas para facilitar a organização dos materiais, a prática e a autonomia dos aprendentes. O projeto-piloto permitiu analisar tanto os benefícios quanto os desafios da implementação, incluindo problemas técnicos e dificuldades de engajamento dos alunos, propondo soluções para superá-los. Os resultados sugerem que o modelo de treinamento pode ser expandido para incluir uma maior diversidade cultural dos países lusófonos e que ele está preparado para evoluir constantemente para responder às evoluções tecnológicas e às demandas de um público global e conectado. Conclui-se que o ensino de PLNM, com a combinação de métodos pedagógicos inovadores e recursos tecnológicos, tem o potencial de promover uma experiência de aprendizado enriquecedora e acessível.
- Computational Evaluation of Heat Exchangers in Hydrogen-Fueled Gas TurbinesPublication . Diogo, Luís Martinho de Figueiredo Moura; Brojo, Francisco Miguel Ribeiro ProençaThis Dissertation presents the computational evaluation of heat exchangers used in hydrogenfueled gas turbines, addressing the growing need for efficient and sustainable propulsion systems. A computational tool was developed to model and predict key performance metrics of heat exchangers, including heat transfer rates, pressure drops, NTU, and effectiveness, across a wide range of operating conditions. The study applies both single-node and multinode approaches. The validation and parametric studies, however, are performed exclusively using the single-node method. These studies thoroughly analyze the impact of critical parameters, including combustor stagnation temperature, mass flow rate, throat area, and cooling channel configurations, on the overall performance of heat exchangers. The validation showed highly accurate predictions at aircraft Mach numbers 1.5 and 2, with minimal deviations. However, as aircraft Mach numbers increased to 3 and beyond, the accuracy decreased due to the inherent limitations of the single-node method, which oversimplifies the flow and temperature gradients within the combustor and cooling channels. Parametric studies revealed that increasing mass flow rates and optimizing throat areas resulted in significant improvements in both heat transfer rates and cooling efficiency. Notably, counterflow configurations consistently outperformed parallel flow designs, yielding up to 12% greater effectiveness, particularly at elevated stagnation temperatures. These findings underscore the importance of carefully optimizing heat exchanger design to enhance the efficiency of hydrogen-fueled gas turbines, especially in high-performance aerospace applications. Future work will focus on validating the multi-node approach to enhance the model’s accuracy in predicting spatial variations in temperature, pressure, and flow characteristics. Additionally, incorporating wall interaction effects and thermal resistance will further refine heat transfer predictions, optimizing the design of heat exchangers for hydrogen-fueled propulsion systems.