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Exposure to NO2 in children’s parks during a high pollution episode based on mesoscale simulations
No full textPublisher Copyright: © 2025. The Author(s), under exclusive licence to Springer Nature Switzerland AG.Air pollution is one of the greatest environmental risk factors for Human health, especially worrying in urban areas, where children are one of the most vulnerable sectors. Continuous information of exposure to different air pollutants is therefore needed, especially in areas where children spend most of their time, such as urban parks. In this study, we use 500 m horizontal resolution mesoscale simulations to assess children’s exposure to NO2 during a high pollution episode in five urban parks across Vitoria-Gasteiz. Children living at a maximum 5-min walking time from each park are considered for exposure calculation. Results show that four parks exceed current hourly limit values, and all of them exceed the daily limits defined by the World Health Organization 2021 guideline. The use of hourly values instead of the daily mean for pollutant exposure calculation shows that the latter underestimates morning exposure and overestimates evening exposure. This result highlights the need for high time resolution to achieve better exposure assessment. The spatial resolution used in this study also shows the capacity to differentiate between parks, improving the exposure estimates with respect to the use of official air quality stations. This methodology provides continuous information to assess short-term exposure, especially important in a high pollution episode, and allows for pollution gaps filling for long-term exposure studies.Peer reviewe
Short-loop recycling of elevator motor magnets by hydrogen decrepitation and FAST sintering
Full text linkPublisher Copyright: © M. Lagos et al., Published by EDP Sciences, 2025.The increasing demand for permanent magnets based on Rare Earths (RE) in Europe, driven by the electrification of mobility and the growth of renewable energy technologies, poses significant supply risks due to the dependence on imports from China. With less than 1% of RE magnets recycled in the EU and no established remanufacturing value chain, there is a pressing need to enhance strategic autonomy in REs. The European Union’s commitment to a circular economy requires innovative solutions to address this complex challenge. This work presents a short-loop recycling process for RE magnets, where magnets are converted into powder through hydrogen decrepitation and subsequently re-converted into new magnets through FAST sintering. This innovative approach enables the recovery of high-quality RE magnets, reducing waste and the demand for primary materials. The process is demonstrated through a case study on elevator motors, a key application where RE magnets play a critical role.Peer reviewe
Enhancing FOWT performance through GA-based control parameter optimisation: A trade-off between power and fatigue
No full textPublisher Copyright: © 2025Floating offshore wind turbines (FOWTs) are crucial for the clean energy transition. To ensure cost-effective and competitive deployment, it is essential to maximise power generation while extending operational lifetime. Environmental forces such as wind, waves, and currents induce structural fatigue, reducing lifespan. Optimising control strategies is vital, as they influence turbine dynamics, mitigate environmental loads, and enhance performance. Genetic Algorithms (GAs), inspired by biological evolution, are effective tools for optimising these strategies due to their robustness in handling complex, non-linear systems, improving both performance and durability. This study presents a methodology for optimising the Reference Open-Source Controller (ROSCO) parameters for a coupled FOWT model using GAs. The primary objective is to reduce structural fatigue without compromising power output. The approach follows a bottom-up strategy—starting with a limited set of tuning parameters and load cases, then progressively increasing complexity—to develop a comprehensive and generalisable optimisation framework. The methodology includes simulation time reduction techniques to ensure computational feasibility. Results: Show that the optimised controller achieves up to a 10.04 % reduction in tower base bending moment fatigue loads while maintaining power output within 7.40 % of the baseline. The analysis also highlights the trade-offs between control parameters and performance metrics, offering insights into their relative influence. This work contributes a flexible, scalable optimisation framework applicable to various FOWT designs and sites, with potential to reduce operational costs and extend turbine lifespan in real-world offshore wind technologies.Peer reviewe
Adaptive Positive-Negative Inertia-Emulation Control for Grid-Connected and Interlinking Converters
No full textPublisher Copyright: © 2025 IEEE.The contribution of virtual inertia through grid-connected converters is essential to tackle the stability issues that arise from the substitution of traditional synchronous generators by converter-interfaced systems. In the last decade, different adaptive virtual inertia controllers have been proposed, but the contribution of negative inertia to the transient response of grids has not been addressed yet. In this paper, an adaptive positive-negative inertia (A-PNIE) control is proposed, where the inertial contribution of the converter is optimised according to grid conditions. In addition, a Dual A-PNIE control is proposed for interlinking converters (IC), which adapts the bidirectional inertia support by switching from positive to negative inertia. A key advantage of the proposed controller is that it can be used for ac and dc grids interchangeably, using a per-unit representations of the frequency and voltage. The simulation results at a single-grid and two-grid scenario, and the experimental results on the single-grid scenario emulated at a Power-HIL testbench demonstrate the effectiveness and feasibility of the proposed controller, as well as the role of the negative inertia concept in accelerating the recovery of the frequency towards its nominal value after a power perturbation.Peer reviewe
Preface to the special issues of the 15th European Wave and Tidal Energy Conference (EWTEC 2023)
Full text linkExtending the Generalized Bode Criterion to Black-Box Power Systems: A Practical Approach for Stability Evaluation
No full textPublisher Copyright: © 2025 IEEE.Impedance-based stability analysis techniques are increasingly used to assess the stability of power converter-dominated power systems. Among these techniques, the Generalized Bode Criterion (GBC) has emerged as a robust method, combining the strengths of the Nyquist Stability Criterion (NSC) with the ease of application of the Bode criterion. However, the GBC requires knowledge of the phase derivative at 0 Hz, which can be challenging to obtain when the system transfer function is analytically unknown. This paper proposes and proves a mathematical relation to eliminate the need for the phase derivative in the GBC. Consequently, all necessary information required for the GBC can be directly obtained from the system Bode plot, enabling the application of the GBC to power systems represented by black-box models with no detailed internal information. The proposed approach is validated by analyzing the stability of a DC-DC converter connected to a DC grid and comparing the results with time-domain simulations.Peer reviewe
A Study on Phosphorous-Based Flame Retardants for Transparent PET Composites: Fire, Mechanical, and Optical Performance
Full text linkPublisher Copyright: © 2025 by the authors.Flame-retardant poly (ethylene terephthalate) composites (FR PET) have been developed with the potential to be used as substrates in applications where flexibility and transparency are required. Several phosphorous-based flame retardants of a different nature were selected here for compounding by melt blending with a low-molecular-weight PET polymer. The fire reaction, transparency, and mechanical properties were analyzed. TGA and cone calorimetry were used to elucidate the gas-phase and condensed-phase actions of flame retardants and their effectivity. Cone calorimeters showed an improved performance with the addition of flame retardants, particularly a reduction in generated heat, improving the FGI (fire growth index) value. However, a V0 classification (following the UL94 standard) was achieved only with the addition of an organic phosphonate, Aflammit PCO900, to the PET matrix. This behavior was linked to the early reaction of this flame retardant in the gas phase, in addition to a plastification effect that causes the removal of the polymer from the incident flame. The presence of flame retardants reduced the transparency of composites over the neat PET, but, nevertheless, a good optical performance remained. No special effect was observed on the crystallization parameters. Therefore, the increase in opacity can be attributed to the poor miscibility of flame retardants and/or differences in the diffraction index of the polymer and FR additives.Peer reviewe
High-Pressure Die Casting (HPDC) Process Parameters Optimization for Al-Mg-Fe Aluminum Alloy Structural Parts Manufacturing
Full text linkPublisher Copyright: © 2025 by the authors.The increasing adoption of High-Pressure Die Casting (HPDC) technology in the production of automotive body structure components is driven by its potential for efficiency and performance. This technology, however, involves complex physical phenomena with numerous parameters that significantly influence casting quality. In this study, three key die casting parameters—plunger or shot speed, vacuum application, and intensification pressure (IP)—have been evaluated following a Design of Experiment (DoE) approach. The results demonstrate that IP application is instrumental in reducing porosity within the cast specimens, thereby enhancing their mechanical strength and elongation. Furthermore, the combined application of vacuum and IP yields further improvements in elongation by minimizing porosity. These findings are particularly relevant for silicon-free alloys, which eliminate the need for post-casting heat treatments to achieve the required mechanical properties. By optimizing HPDC processes, manufacturers can reduce rejection rates, lower production costs, and improve the overall efficiency of their operations, contributing to the production of high-quality and cost-effective components for the automotive industry.Peer reviewe
Similarity-based Recommendation of Existing Component Configurations in Component-based Product Lines
No full textPublisher Copyright: © 2025 Copyright held by the owner/author(s).Component-based product lines enable the systematic reuse of predefined assets to create new systems satisfying a variable set of requirements. When a new project arrives with its concrete features to satisfy, there is an economic- and quality-driven interest in identifying which of the existing component configurations from previous successful projects should be reused to reduce the needed adaptations. Given a real scenario of a component-based product line from our industrial partner, the contribution is a recommender system, mining existing assets and using similarity-based techniques, allowing domain experts to be faster and more confident in the decision-making process of component selection.Peer reviewe
FEM-Assisted Design and Characterization of a New Lithium Battery Pack-Heatsink Assembly
No full textPublisher Copyright: © 2025 IEEE.This work focuses on the design - driven by thermal simulations based on the finite element method (FEM) - and characterization of an assembly for temperature regulation of lithium battery packs. In this study we aim at developing a solution to achieve uniform temperature control over the cells of the battery pack. To this end, we included an aluminum plate featuring pins that thermally connect the battery pack to heat exchangers. To set the desired cell temperature, we considered thermal management systems with either air- or liquid-cooled heatsinks. Our findings indicate that a traditional serpentine liquid heatsink is particularly effective. Within the module, the heat transfer relies mainly on the aluminum plate and pins, which are designed to minimize the thermal resistance towards the heatsinks and to provide large thermal capacitance. This paper shows the main details of the FEM model, together with some validation results obtained using a dedicated test bench.Peer reviewe