ICI - AeroG-LAETA | Documentos por Auto-Depósito
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- Flapping Airfoil Aerodynamics using Recurrent Neural NetworkPublication . Pereira, João A.; Camacho, Emanuel A. R.; Marques, Flávio D.; Silva, AndréThe recent increase in interest in artificial intelligence and neural networks has stirred up various industries. Inevitably, its application will trickle down to the most fundamental studies, for instance, unsteady aerodynamics. The present paper serves the purpose of exploring the ability of a recurrent neural network to predict flapping airfoil aerodynamics, in particular the lift coefficient of a plunging NACA0012 airfoil. Thus, a neural network is designed and trained using motion parameters, such as motion frequency and effective angle of attack, to output the instantaneous lift coefficient over a plunging period. Training data is generated using a panel code (HSPM) for fast generation and early testing. Results show that the neural network can adequately predict the lift coefficient for various conditions, including plunging kinematics that are far from the training domain. Future work will build on this framework and extend it to other aerodynamic coefficients using CFD results and experiments, which should enhance the value of the estimates.
- Dynamic Stall Mitigation Using a Deflectable Leading Edge: The IK30 MechanismPublication . Camacho, Emanuel A. R.; Silva, A. R. R.; Marques, Flávio D.One major problem affecting rotor blade aerodynamics is dynamic stall, characterized by a series of events where transient vortex shedding negatively affects drag and lift, leading to abrupt changes in the wing’s pitching moment. The present work focuses on the mitigation of such effects by using a modified NACA0012 airfoil—the NACA0012-IK30 airfoil—previously used for thrust enhancement in flapping propulsion. An experimental rig is designed to study the advantages of a deflectable leading edge on a plunging and pitching wing, more specifically its influence on the aerodynamic coefficients over time. In the first stage, results indicate that the proposed IK30 mechanism does mitigate the stall effects under static conditions, with stall visualization data corroborating it. Regarding time-varying conditions, the data presents the adequacy of the proposed geometry under different plunging and pitching conditions, which, when correctly used, can mitigate or even eradicate the adverse effects of dynamic stall experienced, leading to significant drag reductions and modest lift enhancements. In the absence of a dynamic stall, the movable leading edge can also provide operational advantages, where it does not negatively affect drag or lift but can reduce the pitching moment intensity by indirectly shifting the pressure center. This study contributes to the long-standing discussion on how to mitigate the adverse effects of dynamic stall by providing an innovative yet simple solution.
- Influence of aluminum nanoparticles in alternative fuel: Single droplet combustion experiments and modelingPublication . Ferrão, Inês; Mendes, Tomás; Mendes, Miguel; Moita, A. S.; Silva, A. R. R.In this work, the effect of adding aluminum nanoparticles on hydrotreated vegetable oil was investigated experimentally and numerically in terms of nanofuel stability and single droplet combustion. The purpose is to understand the phenomena related to isolated droplet combustion when metallic particles are added to a liquid biofuel. Falling droplet combustion experiments were conducted in a drop tube furnace at two different furnace temperatures (800 C and 1000 C) using a high-speed camera coupled with a high magnification lens to investigate the droplet size evolution as disruptive burning phenomena. In numerical terms, a simplified macroscopic model was developed to predict the burning behavior of isolated nanofuel droplets, considering hexadecane as a surrogate fuel for the biofuel. The results reveal that adding nanoparticles resulted in a departure from the -law. Moreover, an increase in the overall droplet burning rate was observed, and according to the numerical results, nanoparticle radiation absorption is the responsible mechanism. Micro-explosions occurred for all nanofuels, and this disruptive burning behavior substantially influenced the droplet lifetime.
- Housekeeping System for Suborbital Vehicles: VIRIATO Mock-Up Vehicle Integration and TestingPublication . Rodrigues, Geraldo; Arribas, Beltran; Melício, Rui; Gordo, Paulo; Valério, Duarte; Casaleiro, J.; Silva, AndréThe work presented in this paper regards the improvement of a housekeeping system for data acquisition of a suborbital vehicle (VIRIATO rocket or launcher). The specifications regarding the vehicle are presented and hardware is chosen accordingly, considering commercial off-the-shelf components. Mechanical and thermal simulations are performed regarding the designed system and a physical prototype is manufactured, assembled and programmed. Functional and field test results resorting to unmanned aerial vehicles, as well as the system’s integration within VIRIATO project’s mock-up vehicle, are presented. These tests demonstrate the viability of this system as an independent data acquisition system, and simulation results show that commercial off-the-shelf components have the capability of surviving expected launch environments.
- Microstructural properties of Asian hornet nest paper-like materials: Preliminary step towards biomimicry materials for civil engineering applicationsPublication . Sedira, Naim; Pinto, Jorge; Gomes, Ana; Nepomuceno, Miguel; Pereira, SandraThis paper presents a comprehensive examination of the microstructure and mineralogy of the paper-like material found in Asian hornet nests (referred to as AHN P-LM) and the nearby tree leaves, utilising scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD). The analysis conducted through SEM-EDS demonstrates that AHN P-LM is primarily composed of plant fragments, with slight traces of inorganic substances (such as CaOx). The thread-like morphologies observed in the SEM analysis, which are linked to the secretion of hornets, warrant attention due to their significance in understanding the microstructure of AHN P-LM. The presence of nitrogen (N) in the EDS analysis of AHN P-LM, in contrast to its absence in analysed leaves, strongly implies that the nitrogen originates from hornet saliva. Additionally, SEM-EDS analysis revealed the impact of chemical composition variations on colour differences within AHN P-LM. Furthermore, X-ray diffraction analysis on ash samples from AHN P-LM confirmed the presence of minerals such as quartz, lime, phlogopite, and microcline. These findings about mineral composition align closely with results obtained from SEM-EDS analyses, presenting various aspects related to understanding the structure and compositional makeup of AHN P-LM. Biomimicry principles can be applied to draw inspiration from the AHN P-LM for replication in the civil engineering field, facilitating innovative solutions. Understanding hornet behaviour and nest material composition is essential. Future outlook includes utilising these materials in wood construction, 3D printing for structural components, shelters, infrastructure repair, green building, and architectural innovation.
- Development of dual-crosslinked Pluronic F127/Chitosan injectable hydrogels incorporating graphene nanosystems for breast cancer photothermal therapy and antibacterial applicationsPublication . Pouso, Manuel António do Rosário; Melo, Bruna L.; Gonçalves, Joaquim; Mendonça, António; Correia, I.J.; Diogo, Duarte de MeloNanomaterials with responsiveness to near-infrared light can mediate the photoablation of cancer cells with an exceptional spatio-temporal resolution. However, the therapeutic outcome of this modality is limited by the nanostructures’ poor tumor uptake. To address this bottleneck, it is appealing to develop injectable in situ forming hydrogels due to their capacity to perform a tumor-confined delivery of the nanomaterials with minimal off-target leakage. In particular, injectable in situ forming hydrogels based on Pluronic F127 have been emerging due to their FDA-approval status, biocompatibility, and thermosensitive sol–gel transition. Nevertheless, the application of Pluronic F127 hydrogels has been limited due to their fast dissociation in aqueous media. Such limitation may be addressed by combining the thermoresponsive sol–gel transition of Pluronic F127 with other polymers with crosslinking capabilities. In this work, a novel dual-crosslinked injectable in situ forming hydrogel based on Pluronic F127 (thermosensitive gelation) and Chitosan (ionotropic gelation in the presence of NaHCO3), loaded with Dopamine-reduced graphene oxide (DOPA-rGO; photothermal nanoagent), was developed for application in breast cancer photothermal therapy. The dual-crosslinked hydrogel incorporating DOPA-rGO showed a good injectability (through 21 G needles), in situ gelation capacity and cytocompatibility (viability > 73 %). As importantly, the dual-crosslinking improved the hydrogel’s porosity and prevented its premature degradation. After irradiation with near-infrared light, the dual-crosslinked hydrogel incorporating DOPA-rGO produced a photothermal heating (ΔT ≈ 22 °C) that reduced the breast cancer cells’ viability to just 32 %. In addition, this formulation also demonstrated a good antibacterial activity by reducing the viability of S. aureus and E. coli to 24 and 33 %, respectively. Overall, the dual-crosslinked hydrogel incorporating DOPA-rGO is a promising macroscale technology for breast cancer photothermal therapy and antimicrobial applications.
- Material de Construção do Ninho da Vespa Asiática - Um contributoPublication . Sedira, Naim; Gomes, Ana; Nepomuceno, Miguel; Paiva, Anabela; Bentes, I.; Pinto, Jorge Tiago Queirós da Silva; Pereira, SandraMuitos trabalhos de investigação têm vindo a ser desenvolvidos no sentido de encontrar novas soluções para os diversos contextos da ciência através da bio-inspiração. Este trabalho está centrado no estudo do ninho da vespa asiática e, em particular, no estudo do seu material de construção. Esta construção natural é complexa em todas a vertentes. A sua complexidade arquitetónica, estrutural, material, funcional, entre outros aspetos técnicos, são fatores que despertam a curiosidade, esta construção pode ainda apresentar dimensões relativamente grandes. Ela é construída e usada aproximadamente meio ano e não volta a ser reutilizada. Este é outro aspeto técnico que motiva um estudo tendo em conta a escassez de habitação a nível mundial. O material de construção também é interessante e inovador. Neste ponto, tentou-se compreender a constituição deste material através da realização de ensaios MEV-EDS de amostras do material do ninho retiradas em diferentes zonas. Amostras de folhas de árvore foram analisadas para serem usadas como referência. As imagens de MEV mostram que o ninho da vespa asiática é feito de fibras vegetais e pedaços de madeira mastigadas, com sulcos e poros para manipulação, troca de gases e regulação de temperatura e humidade. A análise EDS do material do ninho de vespas asiáticas indica origem vegetal, com elementos como carbono (C) e oxigénio (O) formando 82,31%, e magnésio (Mg), potássio (K), cálcio (Ca) e ferro (Fe) constituindo 9,43%. Alumínio (Al) e silício (Si) representam 7,41%. A saliva das vespas é crucial para a construção. Importa acrescentar que este material é utilizado na construção da fachada do ninho, a qual, apesar de estar diretamente exposta às intempéries, proporciona uma durabilidade adequada. O interior do ninho da vespa asiática também garante o conforto necessário para a reprodução destes insetos. Este trabalho tem como principal objetivo partilhar com a comunidade cientifica alguns dos resultados alcançados por esta equipa de investigação neste contexto.
- List of Departures from LIS Airport from March 7, 2023 until March 13, 2023Publication . Fernandes, Ricardo; Magalhães, Leandro; Ferreira, Ana FilipaThis document contains statistical data from one week, including the real number of departures for each type of aircraft (engine) at Lisbon airport (LIS). The analysis was conducted from March 7, 2023 until March 13, 2023. The chosen period was based on the application of the randomness criterion and availability to obtain this information. The traffic sample for the referred period is obtained from an online database (Flight Radar 2024) which keeps data relatively to all the arrivals and departure from LIS airport. The data acquired by the database is from different sources, the main one being Automatic Dependent Surveillance-Broadcast (ADS-B). According to the analyzed data available at ANAC, the period under analysis, regarding the monthly traffic variation at the airport, represents approximately an average month (only around 4.6% below the average monthly movements for the year 2023), which seems appropriate for this analysis given that the aim is to achieve an annual average of movements and emissions. This fact has been observed for the current year, a fact that is in line with previous years. It was also observed that February corresponds to the month with the lowest air traffic, and the month of August represents the peak of operations at the airport under analysis.
- List of Arrivals from LIS Airport from March 7, 2023 until March 13, 2023Publication . Fernandes, Ricardo; Magalhães, Leandro; Ferreira, Ana FilipaThis document contains statistical data from one week, including the real number of arrivals for each type of aircraft (engine) at Lisbon airport (LIS). The analysis was conducted from March 7, 2023 until March 13, 2023. The chosen period was based on the application of the randomness criterion and availability to obtain this information. The traffic sample for the referred period is obtained from an online database (Flight Radar 2024) which keeps data relatively to all the arrivals and departure from LIS airport. The data acquired by the database is from different sources, the main one being Automatic Dependent Surveillance-Broadcast (ADS-B). According to the analyzed data available at ANAC, the period under analysis, regarding the monthly traffic variation at the airport, represents approximately an average month (only around 4.6% below the average monthly movements for the year 2023), which seems appropriate for this analysis given that the aim is to achieve an annual average of movements and emissions. This fact has been observed for the current year, fact that is in line with previous years. It was also observed that February corresponds to the month with the lowest air traffic, and the month of August represents the peak of operations at the airport under analysis.
- Red blood cell membrane-camouflaged gold-core silica shell nanorods for cancer drug delivery and photothermal therapyPublication . Rodrigues, Ana Carolina F.; Correia, I.J.; Moreira, André F.Gold core mesoporous silica shell (AuMSS) nanorods are multifunctional nanomedicines that can act simultaneously as photothermal, drug delivery, and bioimaging agents. Nevertheless, it is reported that once administrated, nanoparticles can be coated with blood proteins, forming a protein corona, that directly impacts on nanomedicines’ circulation time, biodistribution, and therapeutic performance. Therefore, it become crucial to develop novel alternatives to improve nanoparticles’ half-life in the bloodstream. In this work, Polyethylenimine (PEI) and Red blood cells (RBC)-derived membranes were combined for the first time to functionalize AuMSS nanorods and simultaneously load acridine orange (AO). The obtained results revealed that the RBC 41 derived membranes promoted the neutralization of the AuMSS’ surface charge and consequently improved the colloidal stability and biocompatibility of the nanocarriers. Indeed, the in vitro data revealed that PEI/RBC-derived membranes’ functionalization also improved the nanoparticles’ cellular internalization and was capable of mitigating the hemolytic effects of AuMSS and AuMSS/PEI nanorods. In turn, the combinatorial chemo-photothermal therapy mediated by AuMSS/PEI/RBC_AO nanorods was able to completely eliminate HeLa cells, contrasting with the less efficient standalone therapies. Such data reinforce the potential of AuMSS nanomaterials to act simultaneously as photothermal and chemotherapeutic agents.