Desenvolvimento de um sistema ativo de gestão de baterias para aplicações de mobilidade elétrica

Dissertação de mestrado em Engenharia Eletrónica e de ComputadoresA mobilidade elétrica tem-se demonstrado uma área em grande crescimento e destaque, muito por causa dos problemas ambientais e energéticos. Atualmente há uma grande aposta no desenvolvimento da indústria de veículos elétricos, que usam como principal fonte de armazenamento de energia bancos de baterias ligadas em série. Como não existem baterias exatamente iguais, com o tempo, esse agrupamento de baterias apresenta desequilíbrios de tensão entre as mesmas. Por consequência, esses desequilíbrios causam um impacto negativo na capacidade de carga do banco de baterias e no tempo de vida útil de cada bateria. Atualmente torna-se indispensável a utilização de um sistema de gestão de baterias, conhecido na literatura como Battery Management System (BMS). Este tipo de sistema visa melhorar o desempenho das baterias, i.e., fazer a monitorização de parâmetros, a proteção da bateria contra abusos de utilização, o controlo da carga e descarga, e principalmente, fazer o equilibro da carga entre as baterias do mesmo sistema. Em suma, um BMS tem como objetivo preservar a vida útil de cada bateria. Inicialmente, nesta Dissertação de Mestrado, é apresentado o estado da arte relativo aos sistemas de gestão de baterias, onde são apresentados alguns exemplos de BMS existentes no mercado, bem como algumas topologias de equalização (passivas e ativas). Seguidamente são realizadas várias simulações computacionais, com recurso à ferramenta PSIM, para validar o princípio de funcionamento de algumas topologias ativas que utilizam condensadores como o elemento de transferência de energia. Posteriormente, é apresentado todo o desenvolvimento de hardware e software para a implementação da topologia ativa switch matrix with capacitor. Por fim, são apresentados os resultados experimentais da topologia implementada, juntamente com as conclusões do trabalho.In the recent years, electric mobility has become a prominent issue with plenty of developments, mainly due to environmental and energy concerns. Nowadays, the electric vehicle industry is experiencing significant research and development using supply batteries banks connected in series as the main energy storage system. Since there are no exactly equal batteries, along the time this group of batteries will present voltage imbalances between them. These imbalances have a very negative impact on the battery pack capacity and individual battery lifetime. In most battery applications it has become essential to use a battery management system (BMS). This type of system aim to improve battery performance, i.e., to monitor parameters, battery system protection against damages, control of charge and discharge processes and mainly ensure the balance between the batteries’ capacity. Briefly, a BMS aims to preserve the lifetime of each battery. Initially, this master dissertation presents the state of the art regarding battery management systems, where some examples of existing BMS on the market are presented, as well as some equalization passive and active topologies. Furtherly, various computer simulations are carried out using the PSIM tool to validate the operating principle of some active topologies that use capacitors as energy transfer element. Subsequently, the development of hardware and software for implementing the active topology switch matrix with capacitor is presented. Lastly, the experimental results of the implemented topology are presented together with the conclusions of the work

Dermal extracellular matrix extracts for wound healing: a pleiotropic trigger

Apresentação efetuada no "Tissue Engineering and Regenerative Medicine International Society (TERMIS) European Chapter Meeting" , em Manchester, Reino Unido, 2023INTRODUCTION: Extracellular matrix (ECM) role is defined by direct cell‐ECM interactions and biomechanics and also by its capacity to store biochemical cues that are vital in tissue's repair. With this in mind, an in‐house method was devised to obtain extracts comprised of structural ECM components (strECM) and enriched in soluble ECM‐derived factors (sECM). Herein we hypothesised that each ECM fraction may trigger different biological functions in multiple cell types, objectively confering them therapeutic and biomimetic potential. METHODS: To prove the concept, we used human dermal fibroblasts (hdFBs) to obtain the ECM extracts, prepared by fractioning cultured cells' own ECM. Extracts were analysed by mass spectrometry to obtain a proteomic profile and then regarding their in vitro functionality. Human dermal endothelial cells (hDMECs), keratinocytes (hKCs) and dFBs, were used to confirm the features identified by the proteomic profiling. The effect of the extracts over cell adhesion (focal adhesion formation) was analysed. A Matrigel assay was used to evaluate a potential angiogenic effect of the extracts. Moreover, hKCs migration and ability to differentiate and form a stratified epidermis was assessed. Finally, matrix (Collagen, elastin, GAGs) deposition by hdFBs and metalloproteinases (MMP 1, 2, 9)secretion and activity were measured. RESULTS: Proteomic analysis revealed that strECM and sECM complement each other, preserving the native ECM protein profile. The GO accessions linked to each fraction allowed pinpointing the specific cues provided by either of them. strECM was mainly comprised of components that were able to promote cell adhesion and spatial organization. On the other hand sECM proteomic profile revealed factors that play a role in wound healing such as angiogenesis, ECM remodeling and re‐epithelialization. A dose‐dependent response was observed regarding the formation of tubular structures in the angiogenic assay. The presence of sECM leads to a significant increase in the migration and proliferative ability (Ki67) of hKCs while maintaining their phenotype. Finally, sECM led to enhanced collagen, elastin and GAGs deposition by hDFbs while increasing the expression of MMPs. DISCUSSION & CONCLUSIONS: Our results validate the hypothesis that each ECM fraction effectively triggers different biological functions in multiple cell types. Overall the presence of sECM boosted the major cellular mechanisms that lead to successful wound healing, while strECM provides cues for cellular adhesion and organization. This study supports the use of ECM extracts as a wound healing enhancer, which might aid in the development of future therapies or improve the biomimicry of ECM‐based 3D tissue models

Burnout and dropout intention in medical students: the protective role of academic engagement

Introduction: The infuence of burnout, academic engagement, and their interaction in dropout intention among medical students should be further studied. Current research shows its consequences are relevant, however, there is little understanding on burnout and academic engagement moderation in dropout intention. The current study tested a model that relates the efects of coping strategies, social support satisfaction, general distress on academic engagement, burnout, and dropout intention, on medical students. Methods: Through an online survey a non-probabilistic sample of one Medical Faculty’s 1st- and 2nd-year students was recruited. Cross-sectional data were collected using psychometric instruments (Maslach Burnout Inventory – Student Survey, Social Support Satisfaction Scale for College Students, Brief COPE Scale for College Students, University Student Engagement Inventory, and Depression, Anxiety and Stress Scale), sociodemographic and academic variables, and analyzed using structural equation modeling. Results: 532 students (76% response rate) enrolled in the study. Latent variables structural model presented a satisfactory ft to the data and confrmed the expected negative path between burnout and dropout intention (βDI<-SB=0.430; p<.001) and the latent moderation burnout x engagement (βDI<-SB*SE=-0.218; p<.001). Conclusion: Academic engagement attenuates the impact of burnout on dropout intention, working as a protective factor. Social support satisfaction and adaptive coping are associated with increased levels of academic engagement, and general distress and maladaptive coping are associated with burnout. Medical Schools should develop interventions to prevent dropout intention, tackle students’ stress and academic challenges, and develop their academic engagement levels.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio

A novel modular voltage balancing topology for active battery management system

This paper proposes a novel modular voltage balancing topology for an active battery management system (BMS). The proposed topology consists of two power stages. The first stage is composed by a switch network, which is responsible for selecting the battery that will provide energy and the battery that will receive energy. In the switch network, for each battery, are used two cells, which allow the operation with bidirectional current flow and bipolar voltage. The second stage is composed by a capacitor used as energy storage element, which consists in the component used to link both batteries. The switch network control and its interaction with the energy storage element is performed by a digital controller. The paper presents the main computer simulations, as well as the main experimental results obtained to validate the proposed voltage balancing topology for an active BMS.This work has been supported by FCT - Fundação para a Ciência e Tecnologia in the scope of the project: PEst-UID/CEC/00319/2013. Mr. Vítor Monteiro was supported by the doctoral scholarship SFRH/BD/80155/2011 granted by the FCT agency

Structural and paragenetic analysis of swarms of bubble like pegmatites in a miarolitic granite from Assunção South – Viseu – Central Portugal

Publicado em "PEG 2013 : Contributions to The 6th International Symposium on Granitic Pegmatites

Retinoic Acid-Mediated Control of Energy Metabolism Is Essential for Lung Branching Morphogenesis

Funding Information: This work has been funded by National funds, through the Foundation for Science and Technology (FCT)\u2013project UIDB/50026/2020 (DOI 10.54499/UIDB/50026/2020), UIDP/50026/2020 (DOI 10.54499/UIDP/50026/2020) and LA/P/0050/2020 (DOI 10.54499/LA/P/0050/2020); by ICVS Scientific Microscopy Platform, member of the national infrastructure PPBI\u2013Portuguese Platform of Bioimaging (PPBI-POCI-01-0145-FEDER-022122); and by the projects NORTE-01-0145-FEDER-000013 and NORTE-01-0145-FEDER-000023, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This work was also supported by the European Research Council (ERC) under the European Union\u2019s Horizon 2020 research and innovation programme (H2020-ERC-2017-STG-GA 759853-StemCellHabitat). Hugo Fernandes-Silva was supported by a doctoral fellowship (PD/BD/137655/2018) from FCT as part of the Inter-University Doctoral Programme in Ageing and Chronic Disease (PhDOC). Publisher Copyright: © 2024 by the authors.Lung branching morphogenesis relies on intricate epithelial–mesenchymal interactions and signaling networks. Still, the interplay between signaling and energy metabolism in shaping embryonic lung development remains unexplored. Retinoic acid (RA) signaling influences lung proximal–distal patterning and branching morphogenesis, but its role as a metabolic modulator is unknown. Hence, this study investigates how RA signaling affects the metabolic profile of lung branching. We performed ex vivo lung explant culture of embryonic chicken lungs treated with DMSO, 1 µM RA, or 10 µM BMS493. Extracellular metabolite consumption/production was evaluated by using 1H-NMR spectroscopy. Mitochondrial respiration and biogenesis were also analyzed. Proliferation was assessed using an EdU-based assay. The expression of crucial metabolic/signaling components was examined through Western blot, qPCR, and in situ hybridization. RA signaling stimulation redirects glucose towards pyruvate and succinate production rather than to alanine or lactate. Inhibition of RA signaling reduces lung branching, resulting in a cystic-like phenotype while promoting mitochondrial function. Here, RA signaling emerges as a regulator of tissue proliferation and lactate dehydrogenase expression. Furthermore, RA governs fatty acid metabolism through an AMPK-dependent mechanism. These findings underscore RA’s pivotal role in shaping lung metabolism during branching morphogenesis, contributing to our understanding of lung development and cystic-related lung disorders.publishersversionpublishe

EAIR 41st Annual Forum in Leiden, The Netherlands 25 till 28 August 2019

Trabalho apresentado em EAIR 41st Annual Forum, 25-28 agosto 2019, Leiden, Países Baixos.Polytechnic Institutes in Portugal: research on the impact of twelve institutes on the local economy Higher Education Institutions are recognized as important actors in regional development. The Portuguese higher education system comprises both Universities and Polytechnic Institutes, which face an increasing pressure to demonstrate that their presence has an impact on the surrounding communities contributing to their economic development. This paper presents the estimation of the economic impact of twelve Polytechnic Institutes, located in quite diverse regions, based on a shared model so that comparisons have a collective framework of analysis. The main results obtained show that the economic impact ranged from 1.8% to 10.6% of the local GDP and that these Institutes are major local employers.info:eu-repo/semantics/publishedVersio

Plasma in textile waste water treatment

[Excerpt] Water is an essential resource for all life forms on this planet. It is also a critical source of anthropogenic social and economic development [1]. Nevertheless, freshwater scarcity is a real issue that is felt worldwide. It is estimated that by the year 2050 around 6 billion people will suffer from potable water scarcity [2]. The depletion of freshwater is a consequence of rapid population growth, climate change, industrial and farming activities, poorly planned urbanization, and economy [3,4]

The socio-economic impact of a Polytechnic Institution in a local economy : some insights of field research

Higher Education Institutions (HEI) are considered important mechanisms of regional development. However, due to the current economic recession and budget constraints, HEIs need to demonstrate the impact that their activities have on the surrounding community that contributes for its economic development. Hence, the aim of this paper is to present the results of a model to estimate the economic impact of different HEIs that are located in regions with different socio-economic development. Moreover, the common framework of analysis, whilst considering the different socio-economic realities, allows the comparisons of the results for the different HEIS

EAIR 35th Annual Forum in Rotterdam, the Netherlands 28-31 August 2013

Higher Education Institutions (HEI) are considered important mechanisms of regional development. However, due to the current economic recession and budget constraints, HEIs need to demonstrate the impact that their activities have on the surrounding community that contributes for its economic development. Hence, the aim of this paper is to present the results of a model to estimate the economic impact of different HEIs that are located in regions with different socio-economic development. Moreover, the common framework of analysis, whilst considering the different socio-economic realities, allows the comparisons of the results for the different HEIS.info:eu-repo/semantics/publishedVersio