ESTCB - Artigos em revistas com arbitragem científica
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Browsing ESTCB - Artigos em revistas com arbitragem científica by Field of Science and Technology (FOS) "Engenharia e Tecnologia"
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- Determination of dynamic elastic properties of 3D-printed nylon 12CF using impulse excitation of vibrationPublication . Garcia, Pedro F.; Ramalho, Armando; Vasco, Joel; Rubén, Rui; Capela, Carlos; MDPIMaterial Extrusion (MEX) process is increasingly used to fabricate components for structural applications, driven by the availability of advanced materials and greater industrial adoption. In these contexts, understanding the mechanical performance of printed parts is crucial. However, conventional methods for assessing anisotropic elastic behavior often rely on expensive equipment and time-consuming procedures. The aim of this study is to evaluate the applicability of the impulse excitation of vibration (IEV) in characterizing the dynamic mechanical properties of a 3D-printed composite material. Tensile tests were also performed to compare quasi-static properties with the dynamic ones obtained through IEV. The tested material, Nylon 12CF, contains 35% short carbon fibers by weight and is commercially available from Stratasys. It is used in the fused deposition modeling (FDM) process, a Material Extrusion technology, and exhibits anisotropic mechanical properties. This is further reinforced by the filament deposition process, which affects the mechanical response of printed parts. Young’s modulus obtained in the direction perpendicular to the deposition plane (E33), obtained via IEV, was 14.77% higher than the value in the technical datasheet. Comparing methods, the Young’s modulus obtained in the deposition plane, in an inclined direction of 45 degrees in relation to the deposition direction (E45), showed a 22.95% difference between IEV and tensile tests, while Poisson’s ratio in the deposition plane (v12) differed by 6.78%. This data is critical for designing parts subject to demanding service conditions, and the results obtained (orthotropic elastic properties) can be used in finite element simulation software. Ultimately, this work reinforces the potential of the IEV method as an accessible and consistent alternative for characterizing the anisotropic properties of components produced through additive manufacturing (AM).
- Dynamic elastic properties of E-Glass randomly oriented fiber reinforced SR GreenPoxy composite - Experimental and numerical analysisPublication . Ramalho, Armando; Gaspar, Marcelo; Correia, Mário; Vasco, Joel; Capela, Carlos; Rubén, RuiIn this article, the in-plane dynamic elastic properties of an E-glass randomly oriented fiber-reinforced SR GreenPoxy 56 composite were obtained based on the procedure specified in the ASTM E1876-21 standard. The experimental frequencies and the ones predicted by the simulation of the experimental procedure using a finite element analysis developed in the Patran/Nastran 2021 package were used in an iterative algorithm using sensitivity analysis to improve the first approaches of the dynamic elastic properties obtained by the impulse excitation technique. These experimental results are compared with the ones obtained by the 2D Short Fiber Composite model of the E-glass randomly oriented fiber-reinforced SR GreenPoxy 56 composite, developed in the Patran/Nastran 2021 software.
- Empirical evidence of AI-enabled accessibility in digital gastronomy: Development and evaluation of the Receitas +Power PlatformPublication . Serra, Paulo; Oliveira, Ângela; Fidalgo, Filipe; Serra, Bruno; Infante, Tiago; Baião, LuísThis study explores how artificial intelligence can promote accessibility and inclusiveness in digital culinary environments. Centred on the Receitas +Power platform, the research adopts an exploratory, multidimensional case study design integrating qualitative and quantitative analyses. The investigation addresses three research questions concerning (i) user empowerment beyond recommendation systems, (ii) accessibility best practices across disability types, and (iii) the effectiveness of AI-enabled inclusive solutions. The system was developed following user-centred design principles and WCAG 2.2 standards, combining generative AI modules for recipe creation with accessibility features such as voice interaction and adaptive navigation. The evaluation, conducted with 87 participants, employed the System Usability Scale complemented by thematic qualitative feedback. Results indicate excellent usability (M = 80.6), high reliability (Cronbach’s α = 0.798–0.849), and moderate positive correlations between usability and accessibility dimensions (r = 0.45–0.55). Participants highlighted the platform’s personalisation, clarity, and inclusivity, confirming that accessibility enhances rather than restricts user experience. The findings provide empirical evidence that AI-driven adaptability, when grounded in universal design principles, offers an effective and ethically sound pathway toward digital inclusion. Receitas +Power thus advances the field of inclusive digital gastronomy and presents a replicable framework for human–AI co-creation in accessible web technologies.
- Evacuation of Lisbon’s Baixa-Chiado subway station in case of firePublication . Borralho, Tiago; Rodrigues, João Paulo; Calmeiro dos Santos, CristinaIt is essential to ensure that any building has conditions for a safe evacuation of its occupants. This aspect is essential in subway stations, where evacuation has to be carried out in an upward way, and usually correspond to large structures constituting a single fire compartment. Baixa-Chiado subway station, in Lisbon, Portugal, was selected for studying the evacuation in case of fire, due to its depth, high number of passengers that frequent the station and the existing of two intersecting train lines. A calculation of evacuation time was calculated and the way of evacuation studied, in different fire scenarios, number and location of occupants. The numerical simulations used Fire Dynamics Simulator and Pathfinder softwares, the first for fire spreading and the second for evacuation analysis. The importance of smoke control system, and its rapid activation in case of fire, was highlighted by the results obtained. In situations where this did not occur, there was a significant worsening in the evacuation of the occupants. It was estimated the incapacitation of a significant number of occupants, considering the levels registered for the fractional effective dose. The station’s architectural constraints proved to be a crucial factor in the results of the study. This article highlights important results applicable to subway stations around the world.
- Gamification and emotional intelligence: Development of a digital application for childrenPublication . Nunes, Maria; Oliveira, Ângela; Fidalgo, FilipeIt is important to work on educating children’s emotional intelligence, namely the re-awareness and control of emotions, both their own and those around them so that they feel empathy for others, establish and maintain positive relationships and make conscious decisions. This document describes a proposal for a gamified solution, based on the development of a multimedia product, which aims to help children, parents and teachers in the education of emotional intelligence in children. The solution makes it possible to present everyday scenarios to children, allowing adults to find out how they feel and, based on this information, to work on feelings and social behaviour. The solution was based on research into studies available in scientific databases on children’s emotional intelligence, as well as research into exercises that can help work on this same issue. Once implemented, the solution was tested with children from a primary school, where it was possible to collect feedback from them and their teachers and make improvements. This study presentsthe design, development and evaluation of a gamified application for children focused on emotional intelligence. The methodology used is based on a systematic literature review following the PRISMA protocol and the development of an iterative multimediaproduct. The study sample included around 200 elementary school children, where it was possible to collect qualitative feedback to evaluate the effectiveness of the application. The results obtained made it possible to make improvements to the design of the application and to obtain feedback from the teachers, which was very positive, but transmitted by direct interview.
- Internet of robotic things evolution, standards and data interoperability best practices for the next generation of artificial intelligence‐powered systemsPublication . Gyrard, Amelie; Freitas, Edison Pignaton de; Serrano, Martin; Li, Howard; Gonçalves, Paulo; Quintas, João; Vermesan, Ovidiu; Olivares‐Alarcos, Alberto; Kung, Antonio; Cavallo, FilippoThe Internet of Robotic Things (IoRT) represents the rise of a new paradigm enabling robots to serve not only as autonomous units but also as intelligent interconnected entities that can interact, collaborate, and share information through the edge, cloud and other data networks. IoRT is a technological progress and the fusion of Robotics with the Internet of Things (IoT), artificial intelligence (AI), and edge‐Computing, IoRT can benefit from the next‐generation spatial web, Web 4.0 (the intelligent immersive knowledge Web), by enhancing data processing, situational awareness, and integration with immersive technologies, software‐defined automation (SDA), and spatial computing technologies. Semantic Web and Web 4.0 technologies are becoming common in robotics projects for exchanging data and enabling data set interoperability. The main challenge is to upgrade how robotic things interact with each other and their environment in a more situation‐aware fashion, enabling IoRT situation‐aware capabilities. This paper reviews the definition of IoRT considering the latest developments in sensor technology and data management systems and uses a novel survey methodology to find, classify, and reuse robotic expertise and present it to the community and engineering experts. The survey is shared through the LOV4IoT‐Robotics ontology catalog, which is available online. This catalog demonstrates how best practices for data sharing and data set interoperability are also used to extract robotic knowledge semi‐automatically. A set of relevant semantic‐enabled projects designed by domain experts that focused on extracting robotic knowledge was included.
- Ontological framework for high-level task replanning for autonomous robotic systemsPublication . Bernardo, Rodrigo; Sousa, João M.C.; Gonçalves, PauloSeveral frameworks for robot control platforms have been developed in recent years. However, strategies that incorporate automatic replanning have to be explored, which is a requirement for Autonomous Robotic Systems (ARS) to be widely adopted. Ontologies can play an essential role by providing a structured representation of knowledge. This paper proposes a new framework capable of replanning high-level tasks in failure situations for ARSs. The framework utilizes an ontology-based reasoning engine to overcome constraints and execute tasks through Behavior Trees (BTs). The proposed framework was implemented and validated in a real experimental environment using an Autonomous Mobile Robot (AMR) sharing a plan with a human operator. The proposed framework uses semantic reasoning in the planning system, offering a promising solution to improve the adaptability and efficiency of ARSs.
- Using drones to estimate and reduce the risk of wildfire propagation in wildland–urban interfacesPublication . Santos, Osvaldo; Santos, NatérciaForest fires have become one of the most destructive natural disasters worldwide, causing catastrophic losses, sometimes with the loss of lives. Therefore, some countries have created legislation to enforce mandatory fuel management within buffer zones in the vicinity of buildings and roads. The purpose of this study is to investigate whether inexpensive off-the-shelf drones equipped with standard RGB cameras could be used to detect the excess of trees and vegetation within those buffer zones. The methodology used in this study was the development and evaluation of a complete system, which uses AI to detect the contours of buildings and the services provided by the CHAMELEON bundles to detect trees and vegetation within buffer zones. The developed AI model is effective at detecting the building contours, with a mAP50 of 0.888. The article analyses the results obtained from two use cases: a road surrounded by dense forest and an isolated building with dense vegetation nearby. The main conclusion of this study is that off-the-shelf drones equipped with standard RGB cameras can be effective at detecting non-compliant vegetation and trees within buffer zones. This can be used to manage biomass within buffer zones, thus helping to reduce the risk of wildfire propagation in wildland–urban interfaces.
- Work faster, work in parallel, or work overtime? An assessment of short-termPublication . Fernandes, Nuno O.; Thürer, Matthias; Costa, FedericaMany firms use short-term capacity adjustments to deal with demand changes over time, and a broad literature assesses when and where to adjust capacity. This study highlights that this may be dependent on the type of capacity flexibility used to actually realize the adjustment. By comparing for the first-time capacity adjustments by speeding up processing rates, working in parallel, or using overtime, significant differences in the operational performance are identified, with the latter resulting in the best percentage tardy performance. This provides important insights for the interpretation of the existing literature, guides the future literature, and helps managers to make better decisions.