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Publication Open Access Corrosion behavior of additively manufactured steels: a comprehensive review(Wiley, 2025-03-21) Villabona Gorri, Eneko; Veiga Suárez, Fernando; Rivero Fuente, Pedro J.; Uralde Jiménez, Virginia; Suárez, Alfredo; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaAdditive manufacturing (AM) is transforming the production of steel components, offering unique advantages such as design freedom and the ability to create complex geometries. This review examines the corrosion behavior of various steel types, including austenitic stainless steels (SS), martensitic SS, duplex SS, low-alloy steels, and maraging steels, produced through AM technologies. In addition, the topic of material hybridization through AM is addressed, which allows for the optimization of the properties of the base materials. While AM often generates finer grain structures, particularly in SS, which enhances corrosion resistance, it can also lead to undesirable phases, precipitates, or defects like porosity that degrade performance. Controlling AM process parameters is crucial to achieving the desired microstructure and optimizing corrosion resistance. The review highlights current knowledge, identifies challenges, and underscores the importance of standardized testing methodologies to enable better cross-study comparisons and guide future advancements in corrosion-resistant AM steels.Publication Open Access Hybrid modelling and identification of mechanical systems using Physics-Enhanced Machine Learning(Elsevier, 2025-11-15) Merino Olagüe, Mikel; Iriarte Goñi, Xabier; Castellano Aldave, Jesús Carlos; Plaza Puértolas, Aitor; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaObtaining mathematical models for mechanical systems is a key subject in engineering. These models are essential for calculation, simulation and design tasks, and they are usually obtained from physical principles or by fitting a black-box parametric input-output model to experimental data. However, both methodologies have some limitations: physics based models may not take some phenomena into account and black-box models are complicated to interpretate. In this work, we develop a novel methodology based on discrepancy modelling, which combines physical principles with neural networks to model mechanical systems with partially unknown or unmodelled physics. Two different mechanical systems with partially unknown dynamics are successfully modelled and the values of their physical parameters are obtained. Furthermore, the obtained models enable numerical integration for future state prediction, linearization and the possibility of varying the values of the physical parameters. The results show how a hybrid methodology provides accurate and interpretable models for mechanical systems when some physical information is missing. In essence, the presented methodology is a tool to obtain better mathematical models, which could be used for analysis, simulation and design tasks.Publication Open Access Study of spacing surface roughness parameters and proposal of a wear behaviour criterion in die-sinking EDM of cobalt-bonded tungsten carbide(Springer, 2025-07-16) Puertas Arbizu, Ignacio; Salvide-González, Unai; Luis Pérez, Carmelo Javier; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PRO-UPNA12514Surface roughness analysis is crucial for assessing machining quality, with most studies emphasizing amplitude parameters due to their industrial relevance. However, spacing roughness parameters, such as Sm (mean spacing of profile irregularities) and Pc (peak count), provide complementary insights into the horizontal distribution of surface features, which are often overlooked. This study investigates the effect of current intensity (I) and pulse time (ti) on Sm and Pc during the die-sinking EDM of cobalt-bonded tungsten carbide (94WC-6Co), a material widely used in wear-intensive applications due to its exceptional hardness. A multilevel design of experiments (DOE) was performed, varying I from 2 to 6 A and ti from 10 to 100 µs. Results demonstrated a strong relationship between machining conditions and both parameters, with higher current intensities increasing feature spacing (Sm) and reducing peak number (Pc). The optimal surface quality, defined by Sm = 30 µm and Pc = 337 cm⁻1, was achieved at I = 2 A and ti = 10 µs. Polynomial regression models provided predictive insights for process optimization. Scanning Electron Microscopy (SEM) analysis validated these results, revealing distinct surface morphology variations associated with the machining parameters. Finally, an attempt to define a criterion for predicting wear behaviour under the experimental conditions considered in this study will be made, where this will be based on Pc and two additional surface roughness parameters such as Rsk (skewness) and Rku (kurtosis).Publication Open Access Valorisation of red mud: disclosing the potential of an abundant residue(MDPI, 2025-02-21) Vielma, Carlos A.; Svobodova-Sedlackova, Adela; Chimenos, Josep Maria; Fernández, A. Inés; Berlanga Labari, Carlos; Rodríguez Trías, Rafael; Barreneche, Camila; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Gobierno de Navarra / Nafarroako GobernuaRed mud (RM), the primary waste product of the aluminium industry, is notable for its high concentrations of metals and rare earth elements (REE). Efforts have been made to develop extraction methods for REE recovery from RM, aiming to enhance its valorisation and reduce the European reliance on external REE sources—particularly crucial for technological advancements and the transition to renewable energy. However, these methods have only been limited to low technology readiness levels (TRLs), with no economically or technically viable processing routes yet defined to enable large-scale industrialisation within a circular economy model. This study characterised RM samples from the Seydişehir region in Türkiye using different techniques and explored the experimental process for recovering metals and REE. Moreover, the study assessed the global prospective potential of RM based on technical and economic data, as well as the sustainability of the implemented process through the life cycle assessment (LCA) tool. Results showed a total REE concentration of up to 1600 ppm, with Ce, being the most abundant (426 ± 27 ppm), followed by La, Nd, and Sc. Concentration efficiencies for La and Nd ranged between 240–300%. Sc, Y, Ce, La, and Nd have significant usage in European markets and represent prime RM targets for further prospecting. The LCA revealed that the highest global warming potential of the sequential extraction process was attributed to hydroxylamine hydrochloride and hydrogen peroxide. The findings highlight the need to explore alternative, more eco-friendly reagents to improve RM valorisation.Publication Open Access Non-destructive spectroscopy-based technologies for meat and meat product discrimination: a review(Elsevier, 2025-10-01) León Ecay, Sara; Insausti Barrenetxea, Kizkitza; López Maestresalas, Ainara; Prieto, Nuria; Ingeniería; Ingeniaritza; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa; Gobierno de Navarra / Nafarroako GobernuaConsumers' confidence in products of animal origin is highly subjected to the quality guarantees offered by the manufacturing and retail industries. Traditionally, meat quality evaluation has been conducted through destructive, time-consuming and chemical-dependent protocols. Smart methodologies based on the non-destructiveness and/or non-contact with the samples, such as spectroscopy-based technologies, arise as an alternative promising tool. This comprehensive overview includes literature published in the last decade applying spectroscopy-based techniques in the Visible (Vis) and near-infrared (NIR) regions of the spectrum (Vis-NIR), either individually or combined with imaging (hyperspectral imaging, HSI), to classify meat and meat products based on ante- or postmortem factors. First, a brief introduction to the fundamentals of Vis-NIRS and HSI is included. Secondly, the main applications of Vis-NIRS and HSI technologies for meat qualitative purposes only are discussed. The Vis-NIRS and HSI have been successfully used in lab scale studies (> 90 % overall accuracy) to discriminate meat and meat products according to antemortem (feeding system, species, origin and breed) and postmortem (freshness, meat quality, label claims) factors. Recently, spectral data collected with handheld Vis-NIR equipment have become more frequent, although the use of portable HSI has not been widely explored. From the studies reviewed, the main concern regarding spectral data is to shorten modelling handling times, including strategies to both extract optimal wavelengths from NIR and compress spectral data from HSI. Despite the efforts made to overcome instrumentation and data processing challenges, a gap remains to be covered up to a real-time implementation in industrial line quality control.Publication Open Access Cladding influence on the milling of low-stiffness aluminum alloy parts with local clamping(Publicaciones DYNA, 2025-03-01) Casuso, Mikel; Rubio Mateos, Antonio; Silveira-Fernández, Elena; Veiga Suárez, Fernando; Lamikiz, Aitzol; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISCThe milling of aeronautical skins on flexible and reconfigurable fixtures is a major industrial challenge due both to the low rigidity of the skins and to the configuration of these fixtures, which, although they provide a great versatility of use and are an efficient alternative to pollutant chemical milling, vibrations can easily occur in them that may impair the surface quality, increase the error of the final thickness and cause excessive cutting forces. Aiming to foster the use of flexible fixtures, a study of the natural frequencies and cutting forces obtained when milling thin parts has been carried out, with special emphasis on analyzing the influence of the cladding of aluminum alloy parts.Publication Open Access The project book: a toolkit for stakeholder management in international development projects(Universidad de Zaragoza, 2024-10-24) Romero de Miguel, Aida; Pérez Ezcurdia, Amaya; Gimena Ramos, Faustino; Ingeniería; Ingeniaritza; Sociología y Trabajo Social; Soziologia eta Gizarte LanaEn este artículo, se presenta una metodología de gestión de proyectos de cooperación internacional al desarrollo diseñada para agentes deslocalizados que, sobre una base tradicional de gestión de proyectos (fases y procesos), añade un sistema documental abierto (libro del proyecto) y la aplicación de técnicas de investigación-acción participativa. El libro del proyecto mejora la transparencia y, por tanto, la confianza y el compromiso. Con las técnicas de investigación-acción participativa, se apoya la gestión intercultural de los agentes de los proyectos. La metodología ha sido probada en tres sectores -«salud», «producción» y «educación»-, ejecutados en Colombia. La calidad y el éxito del proyecto tras su aplicación se caracteriza por una aceptación del 80 % de los agentes.Publication Open Access Experimental investigation of a R290 domestic heat pump equipped with a thermoelectric-aided sub-cooler(Elservier, 2025-06-01) Pendzialek, M.; Özyildiz, Tufan; Fingas, Rafal; Sánchez, Daniel; Aranguren Garacochea, Patricia; Smolka, Jacek; Haida, Michal; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISCThe energy efficiency of heat pumps is an important factor for the sustainability and electrification of domestic heating, especially for the most common air-to-water heat pumps, which are a competitive solution to conventional heating methods. However, novel solutions for cold and moderate climate zones must be developed considering environmentally friendly natural refrigerants such as hydrocarbons. One idea is to introduce a thermoelectric-aided sub-cooler into an air-to-water heat pump to improve the coefficient of performance. Therefore, this work aims to experimentally investigate a novel propane heat pump system with a prototype thermoelectric-aided sub-cooler for domestic heating. Energy analysis was performed to evaluate the energy impact of the sub-cooler in terms of ambient conditions from -10.0 ºC to 5.0 ºC, different water temperatures for heating applications in existing buildings from 45.0 ºC to 55.0 ºC and varying operating conditions of thermoelectric modules in the sub-cooler. The performance of the sub-cooler was evaluated. The results confirm that introducing a thermoelectric-aided sub-cooler can improve the heat pump performance by up to 6.0% and the heating capacity improvement by up to 17.0% for the low ambient temperature of -10.0 ºC. Furthermore, an optimal direct current voltage below 3.0 V was found for every investigated operating condition to ensure the best system coefficient of performance.Publication Open Access Structural and functional analysis of polyethylene glycol-coated zein nanoparticles(Elsevier, 2025-08-20) Calvopiña, Jonathan; Rivero Fuente, Pedro J.; Martínez-Ohárriz, María Cristina; Palacio, José F.; Álvarez Galindo, José Ignacio; Espuelas, Socorro; Irache, Juan M. ; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2The development of nanoparticles for drug delivery purposes is faced to a number of challenges, including the complexity of an adequate physico-chemical characterization, especially when nanoparticles are functionalized. The aim of this work was to evaluate and characterize the structure and properties of zein nanoparticles (approximately 200 nm) functionalized with polyethylene glycol (PEG 35,000) at different PEG-to-zein ratios. The interaction between PEG and zein, attributed to hydrogen bonding between the amide groups of zein and the hydroxyl groups of PEG, was evidenced by FTIR and further confirmed by 2D-COS spectroscopy. DSC and TGA thermograms demonstrated the role of PEG in improving nanoparticle thermal stability, with PEG-coated nanoparticles exhibiting higher decomposition temperatures and increased PEG content with higher PEG-to-zein ratios. SEM and AFM imaging of nanoparticle thin films confirmed that PEG decoration enhanced wettability and reduced the hydrophobicity of bare zein nanoparticles, consistent with Rose Bengal test results. Additionally, AFM analysis of nanoparticle distribution in a mucin thin film demonstrated that PEG coating improved nanoparticle dispersibility within the mucin matrix, in line with previous studies describing the increased diffusivity and mucus-permeation properties of nanoparticles coated with hydrophilic polymers. In summary, this study highlights the importance of an in-depth analysis of the physicochemical characteristics of nanoparticles, providing valuable structural insights that facilitate optimization and the selection of the most suitable compositions for preclinical development.Publication Open Access Multivariable QFT control of the direction flip problem in wire arc additive manufacturing(Wiley, 2025-04-25) Masenlle, Manuel; Elso Torralba, Jorge; Ostolaza, J. Xabier; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISCAdditive metal manufacturing (AM), particularly Wire Arc Additive Manufacturing (WAAM), offers a compelling alternative to traditional machining methods. While AM presents advantages such as reduced material waste and lower production costs, challenges remain in effectively controlling the process to prevent defects and optimise material deposition. This article proposes a multivariable control system for WAAM utilising Quantitative Feedback Theory (QFT) to maintain the shape of the heat-affected zone (HAZ) during transitions in direction flips during layer deposition. By modelling these direction flips as predictable disturbances, the full potential of QFT to integrate feedback and feedforward actions is exploited. The resulting multivariable control laws seek to minimise temperature variation in two critical points around the welding pool by adequately manipulating the power and speed of the heat source. A benchmark system is established to evaluate the effectiveness of the proposed control system. The results demonstrate significant improvement in temperature control, leading to enhanced layer construction quality and reduced need for height corrections or cooling pauses.Publication Open Access Duplex treatments prepared by HiPIMS and sol-gel on biodegradable ZK60 magnesium alloy for biomedical applications(Elsevier, 2025-09-01) Claver Alba, Adrián; Quintana, Iban; Fernández, Iván; Santiago, José A.; Díaz-Rodríguez, Pablo; Panizo-Laiz, Miguel; Zalakain Iriazabal, Iñaki; Urroz Unzueta, José Carlos; García Lorente, José Antonio; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Gobierno de Navarra / Nafarroako GobernuaThe utilization of magnesium-based biomaterials in biomedical applications has grown considerably in recent years due to their favourable biocompatibility, biodegradability, and mechanical properties that closely resemble those of bones. However, the use of Mg-based alloys in aggressive environments, such as human bodily fluids, is hindered by their susceptibility to rapid corrosion, which compromises their mechanical properties. This can lead to infections in the body due to uncontrolled corrosion. In this study, a novel approach was employed to enhance the corrosion resistance of biodegradable ZK60 magnesium alloy and achieve optimal surface properties that can potentially enhance its antibacterial performance, hardness, and toughness. This approach involved the application of duplex treatments consisting of TiN doped with Cu coatings deposited via high power impulse magnetron sputtering (HiPIMS) followed by a Sol-gel top layer. The study systematically investigated the surface properties (wettability, roughness, and morphology), hardness, toughness and adhesion of the coatings to the substrate. To assess the corrosion resistance, mass change and hydrogen evolution of the samples, they were immersed in Hanks Balanced Salts Solution. Electrochemical tests were conducted to estimate the corrosion behavior of the samples. The in-vitro corrosion tests results demonstrated that the duplex treatments enhanced the corrosion resistance of the uncoated magnesium alloy samples. The duplex treatments exhibited suitable properties, including high corrosion resistance, hardness, toughness and adequate values of wettability and porosity-roughness. Therefore, they can be considered a promising option for use in biodegradable magnesium implants.Publication Open Access Recycling bovine ear tags for phase change material encapsulation via electrospinning(Elsevier, 2025-10-01) Alfonso de Miguel, Iker; Calvo-Correas, Tamara; Eceiza, Arantxa; Claver Alba, Adrián; Torresi, Stefano; García Lorente, José Antonio; Zalakain Iriazabal, Iñaki; Ingeniería; Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaIn this study, thermoplastic polyurethane (TPU) from waste bovine ear tags has been processed and recycled as shell material to encapsulate phase change materials (PCMs), enabling the fabrication of thermoregulating core-shell nanofibers via coaxial electrospinning. Notably, this process was achieved in few steps and without the need for heating equipment to melt the injected materials, enhancing its simplicity. Two PCMs were selected based on their melting points; octadecane (OCTA) near room temperature and eicosane (EICO) near body temperature. Composite fibers were prepared at different core solution concentrations (10, 20, 40 and 80 % w/v), with the highest encapsulation efficiency and thermal properties obtained for samples with 80 % (w/v). TPU/PCM electrospun nanofibers were observed by scanning electron microscopy (SEM) with average diameters between 400 and 700 nm. The Fourier transform infrared spectroscopy (FTIR) suggested no further chemical reactions during the fabrication process. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) demonstrated good thermal stability, with latent heats of 62.9 2 J/g and 81.4 J/g for TPU/OCTA80 and TPU/EICO80 membranes, respectively. Thermal cycling tests were conducted for 150 cycles, showing a 5 % enthalpy reduction in TPU/OCTA80 due to crystalline phase degradation, while TPU/EICO80 exhibited a 2 % increase, likely due to PCM restructuring; however, long-term trends suggest a potential decline. This simple, cost-effective and environmentally friendly fabrication process highlights the potential of upcycling TPU waste and offers a scalable approach for developing TPU/PCM membranes with promising applications in textile thermal management systems.Publication Open Access Monitoring of blind rivets installations: contributions from the manufacturing chain and time-series imaging(Elsevier, 2025-10-01) Penalva Oscoz, Mariluz; Gil del Val, Alain; Martín, Ander; Villanueva Roldán, Pedro; Uralde Jiménez, Virginia; Veiga Suárez, Fernando; Ingeniería; Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaFastening is a crucial operation in the aircraft manufacturing cycle, and the demand for automated solutions has grown in recent years. Blind rivets are particularly suitable for automation due to their ease of use. However, fastening with blind rivets requires indirect evaluation of the formed head for in-line quality monitoring. This study presents two approaches to address this problem. Firstly, an analysis of the drilling-riveting chain assesses the impact of the previous operation on riveting outcomes. Secondly, time-dependent signals from the riveting process are coded into images and analysed using deep learning techniques. Despite some limitations, both methods for monitoring blind riveting have demonstrated high precision and accuracy values above 0.9, with 1 indicating perfect precision or accuracy, suggesting that they can reliably predict the quality of rivet installations.Publication Open Access AI algorithms in the agrifood industry: application potential in the Spanish agrifood context(MDPI, 2025-02-17) Arévalo Royo, Javier; Flor Montalvo, Francisco Javier; Latorre Biel, Juan Ignacio; Tino Ramos, Rubén; Martínez Cámara, Eduardo; Blanco Fernández, Julio; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISCThis research explores the prospective implementations of artificial intelligence (AI) algorithms within the agrifood sector, focusing on the Spanish context. AI methodologies, encompassing machine learning, deep learning, and neural networks, are increasingly integrated into various agrifood sectors, including precision farming, crop yield forecasting, disease diagnosis, and resource management. Utilizing a comprehensive bibliometric analysis of scientific literature from 2020 to 2024, this research outlines the increasing incorporation of AI in Spain and identifies the prevailing trends and obstacles associated with it in the agrifood industry. The findings underscore the extensive application of AI in remote sensing, water management, and environmental sustainability. These areas are particularly pertinent to Spain¿s diverse agricultural landscapes. Additionally, the study conducts a comparative analysis between Spain and global research outputs, highlighting its distinctive contributions and the unique challenges encountered within its agricultural sector. Despite the considerable opportunities presented by these technologies, the research identifies key limitations, including the need for enhanced digital infrastructure, improved data integration, and increased accessibility for smaller agricultural enterprises. The paper also outlines future research pathways aimed at facilitating the integration of AI in Spain's agriculture. It addresses cost-effective solutions, data-sharing frameworks, and the ethical and societal implications inherent to AI deployment.Publication Open Access Evaluation of the potential of natural mining by-products as constituents of stabilized rammed earth building materials(MDPI, 2025-05-06) Martín Antunes, Miguel Ángel; Perlot, Céline; Villanueva Roldán, Pedro; Abdallah, Rafik; Seco Meneses, Andrés; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaIn this investigation, different natural by-products were used to modify the Particle Size Distribution (PSD) of a soil to evaluate their potential in Stabilized Rammed Earth (SRE) building. Three different mixes were manufactured: (i) a mix composed entirely of a clayey soil, (ii) a mix consisting of mining by-products and clayey soil and (iii) a mix entirely based on mining by-products. Unstabilized and stabilized samples of the mixes were manufactured using two cement dosages (2.5% and 5%), and the samples were tested for Unconfined Compressive Strength (UCS), soaked UCS, and wetting and drying tests. Mining by-products demonstrated significant potential in SRE building, as their addition to the clayey soil resulted in higher UCS values compared to the UCS obtained from clayey soil alone. Unstabilized samples lost their integrity during exposure to water. The inclusion of mining by-products also showed potential as, although the mixes did not fully meet the requirements for soaked UCS and the wetting and drying tests, the mix containing both mining by-products and clayey soil retained its integrity in water, unlike the samples composed solely of clayey soil. M3C5 successfully met the requirements for soaked UCS and the wetting and drying tests, further highlighting the great potential of mining by-products in SRE building.Publication Open Access Enhancement of sol-gel coatings for photoprotection of rosé wines(MDPI, 2025-02-15) Moriones, Jennifer; Osés Martínez de Zúñiga, Javier; Amézqueta, Pablo; Palacio, José F.; Fernández de Ara, Jonathan; Almandoz Sánchez, Eluxka; Ciencias; Zientziak; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2Exposure to short-wavelength light, including UV-A and blue light, can degrade high-value products like rosé wine, which are usually packaged in colourless bottles. This study investigates the optimisation of sol¿gel coatings enhanced with UV-absorbing additives (Tinuvin 479 and semaSORB 20109) to provide photoprotection for rosé wines. Coatings with varying additive concentrations (0.5%, 0.75%, 1%, and 1.5%) were applied to glass substrates via spin coating and cured with UV light. Then, optical and mechanical characterisation was performed. The 1.5% concentration semaSORB 20109 bilayer coating demonstrated improved photoprotective properties without compromising colour properties, leading to successful application on glass bottles by spray coating. Accelerated degradation tests confirmed that the optimised coating effectively protected against photodegradation, as indicated by the stability of polyphenol levels and colour parameters in rosé wines. The results suggest that these coatings could be a suitable option for commercial-scale applications, enhancing the light resistance of colourless-bottled products.Publication Open Access Multiobjective QFT control as enabler for wind turbines with soft-soft towers(Wiley, 2025-03-06) Arellano Aguado, Jesús; Elso Torralba, Jorge; Ingeniería; IngeniaritzaWind energy tendency towards larger rotors and higher hub heights reach a limit when wind turbine pitch controller bandwidth is constrained by the first tower fore-aft bending moment. While most manufacturers try to find a workaround with alternative nonstandard tower designs, this paper presents a control solution based on quantitative feedback theory (QFT) that provides effective disturbance rejection while maintaining cost-effective conventional tower design for very high hub heights. Frequency domain specifications on measured and nonmeasured variables provide the control designer the insight to make the best use of the available feedback. The new control design procedure is applied to a realistic wind turbine example of 180-m hub height, showing the technical viability of the solution and a profitable business case.Publication Open Access Polycarbonate nanofiber filters with enhanced efficiency and antibacterial performance(MDPI, 2025-02-08) Blanco, Miren; Monteserín, Cristina; Gómez, Estíbaliz; Aranzabe, Estíbaliz; Vilas Vilela, José Luis; Pérez-Márquez, Ana; Maudes, Jon; Vaquero, Celina; Murillo, Nieves; Zalakain Iriazabal, Iñaki; Ruiz Rubio, Leire; Ingeniería; IngeniaritzaThe need for clean and safe air quality is a global priority that extends to diverse environments, including households, industrial spaces, and areas requiring respiratory personal protection. In this study, polycarbonate (PC) nanofiber filters coated with a coating containing a silver salt were prepared by the electrospinning process and a subsequent dipping–extraction method. These nanofiber filters presented the enhancement of air filtration efficiency and reinforcement of antibacterial properties. The research includes diverse PC filter structures, assessing beaded and non-beaded structures and varying areal weights. The study evaluated filtration efficiency across NaCl particle sizes (50–400 nm) and pressure drop outcomes. In addition, the antibacterial activity of the coated filters against E. coli and other coliforms was investigated by the filtration membrane method. Repetitive testing consistently yields high efficiencies, reaching 100% in thicker filters, and minimal air resistance in beaded filters, presenting an advantage over the current systems. Furthermore, the new properties of the filters will enhance environmental safety, and their time of use will be increased since they prevented the growth of bacteria, and no significant colonies were seen. Considering all these factors, these filters presented promising application in environments with harmful microorganisms, for the development of advanced industrial filtering systems or even hygienic masks.Publication Open Access Effect of annealing on the mechanical properties of composites of PLA mixed with Mg and with HA(MDPI, 2025-04-28) Sánchez González, Carmen; Pérez Jiménez, Aurora Fernanda; Malvè, Mauro; Díaz Jiménez, Cristina; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2Polylactic acid (PLA) is a bioresorbable and biocompatible material and is a promising alternative to the current materials used for permanent implants as it has osteosynthesis properties. However, this material has some drawbacks due to its low mechanical and thermal resistance after 3D printing. Extensive research has been conducted to improve the properties of this material, for example, with the addition of other compounds, such as magnesium (Mg) or Hydroxyapatite (HA). These reinforced materials have been shown to reduce the internal stress of the matrix of PLA, improving the thermal, optical and structural properties of the material, even though the performance achieved is lower than needed to be implanted. In addition, although it is known that the addition of Mg or HA affects the mechanical performance of the material, mechanical properties have not been studied in the literature. Thus, the aim of this study is to research the effect of thermal post-processing based on annealing of composites made of PLA with Mg and PLA with HA, manufactured by fused filament fabrication, with the goal of finding an improvement in the mechanical properties of these materials. As a result, different designs of annealing processes have been studied with different reinforced materials and their mechanical properties have been compared, studying axial traction and compression, radial compression as well as flexibility, among others. The comparative results achieved show the relevance of the design of the annealing process for the improvement of the mechanical properties of these materials.Publication Open Access Maximum attenuation variability of isotropic magnetosensitive elastomers(Elsevier, 2016-07-14) Agirre Olabide, Iker; Elejabarrieta, María Jesús; Ingeniería; IngeniaritzaMagnetosensitive elastomers (MSE) are innovative high-tech materials that exhibit changed dynamic properties when an external magnetic field is applied. In this work, the influence of particle content, frequency, temperature and magnetic field on the maximum attenuation of isotropic MSEs was studied. Six particle content types were synthesised using carbonyl iron powder particles embedded in a room-temperature vulcanizing silicone rubber matrix. The characterization of the MSE samples was performed with a Physica MCR 501 rheometer from the Anton Paar Company that is equipped with a magnetorheological cell. All samples were characterized using frequency sweep tests within the lineal viscoelastic region. In addition, a four-parameter fractional derivative model was used and extended over a wide frequency range. The influence of temperature was modelled using the Arrhenius model, coupled with the fractional derivative model. The maximum attenuation is increased with frequency and magnetic field and is independent of temperature.