Artículos de revista DING - INGS Aldizkari artikuluak

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Open Access
AI-driven predictive modeling of homogeneous bead geometry for WAAM processes
(Springer, 2025-07-15) Fernández Zabalza, Aitor; Rodríguez Díaz, Álvaro; Veiga Suárez, Fernando; Suárez, Alfredo; Uralde Jiménez, Virginia; Ballesteros Egüés, Tomás; Alfaro López, José Ramón; Ingeniería; Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
With the increasing number of applications employing additive manufacturing solutions, these deposition processes must become more autonomous, which can be helped by the application of machine learning monitoring. This study presents a fully online, low-cost framework for real-time quality control in Invar wire-arc additive manufacturing (WAAM). Synchronized current and voltage signals are transformed into spatial heatmaps and temporal Markov transition images, which are processed by an optimized ResNet-18 to classify the quality of each layer on-the-fly. Validation using cross-validation on an internal Invar dataset yields an accuracy of up to 94% under clean conditions, with inference times below 20 ms per layer, enabling deployment during natural cooling between layers. These results demonstrate the feasibility of non-intrusive signal-based anomaly detection, enabling rapid identification of weld spalls and useful for scalable and automated WAAM monitoring in industrial environments.
Open Access
Fresh, mechanical, and microstructural properties of sustainable mortars made of two recycled sands from construction and demolition wastes
(American Society of Civil Engineers, 2025-04-28) Seco Meneses, Andrés; Martín Antunes, Miguel Ángel; Espuelas Zuazu, Sandra; Marcelino Sádaba, Sara; Prieto Cobo, Eduardo; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Gobierno de Navarra / Nafarroako Gobernua
This paper analyses the ability of two recycled sands (RSs) from concrete (CON) and masonry (MAS) wastes for the manufacture of mortars for the construction industry. Manufactured sand (MS) was substituted by both RSs at the rates of 25%, 50%, 75%, and 100%. CON combinations did not demonstrate any correlation between workability and the MS replacement ratio, whereas MAS combinations exhibited a direct relationship between these factors. A decrease in the starting and final setting times was observed for both RS combinations and, in general, longer total setting times. CON combinations showed mechanical strength increases for substitution rates between 25% and 50%, whereas MAS reached improved mechanical strength at 25%. Scanning electron microscopy-energy dispersive X-ray (SEM-EDX)-demonstrated tests allowed for mortar microstructure differences and hydration product formation. Thermogravimetric analysis/derivative thermogravimetry (TG/DTG) tests showed hydrated cementitious compounds' formation differences and the consumption of Portlandite between combinations and their evolution during curing.
Open Access
Intergenotypic prediction of reducing sugars in intact potatoes using near-infrared spectroscopy and multivariate analysis
(Elsevier, 2025-12-01) Peraza Alemán, Carlos Miguel; Arazuri Garín, Silvia; Jarén Ceballos, Carmen; Ruiz de Galarreta, José Ignacio; Barandalla, Leire; López Maestresalas, Ainara; Ingeniería; Ingeniaritza; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Potatoes (Solanum tuberosum L.) are among the most widely consumed foods worldwide and are used in various culinary preparations. As a result, their production has increased in recent decades, prompting the potato industry to place greater emphasis on quality control measures for this food. In this context, reducing sugars stand out as being directly linked to the formation of acrylamide, a recognized carcinogen. Although Near Infrared Spectroscopy (NIRS) has been successfully used to predict reducing sugar content in this crop, the applicability of models across different potato cultivars remains limited due to genotypic variability. This study aimed to assess the potential of NIRS (1200¿2200 nm) to predict reducing sugar content across a diverse set of potato genotypes (n = 114). Excellent outcomes were obtained for both full spectrum and selected wavelength models. The results demonstrated high predictive accuracy with an R2 of 0.89 and an RMSE of 0.061 % for calibration, while external predictions in new genotypes yielded an R2 of 0.91 and RMSE of 0.065 % for SVMR model. These findings highlight the feasibility of using NIRS for rapid, real-time and non-destructive assessment of reducing sugars in untested potato genotypes, offering a valuable tool for industry applications.
Open Access
Cost-effective multispectral imaging system for detecting nitrogen over-fertilization under different temperatures in greenhouse sweet pepper plants
(Elsevier, 2025-12-01) Piñero Zapata, María Carmen; Gómez-Candón, David; López Maestresalas, Ainara; Collado-González, Jacinta; Otálora, Ginés; Amor, Francisco Moisés del; Ingeniería; Ingeniaritza; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD
This study investigates the effects of nitrogen (N) excess under two temperature conditions on greenhouse-grown pepper plants (Capsicum annuum L.), using a low-cost cablecam system for proximal remote sensing. Commonly used vegetation indices were analyzed to assess plant responses under varying N treatments (Control, 2 N, and 3 N) and temperature conditions (Control and Control+5 °C). The results showed that vegetation indices exhibited a lower variability in spectral reflectance under high temperature, and moderate correlations with plant traits such as %N and chlorophyll content, particularly under control temperature. However, high temperatures constrained the sensitivity of vegetation indices in detecting variations in N status, suggesting that thermal stress limits the plant¿s ability to effectively utilize and respond to available nitrogen. Additionally, while short-term excess nitrogen application enhanced vegetation indices values in the control temperature setting, prolonged exposure led to oxidative stress, as confirmed by the increase in lipid peroxidation and the reduction in total phenolic content. The low-cost cablecam system provides a practical, versatile, and easily deployable solution for greenhouse environments. Despite only allowing for the control of scrolling speed, the cablecam system, integrated with a GPS-enabled multispectral camera, enabled precise and individual plant monitoring. This approach presents an adaptable alternative to unmanned aerial vehicles in greenhouse settings, demonstrating its potential for accurate monitoring and contributing to improved stress and nutrient management strategies. This study highlights the potential of vegetation indices as practical tools for assessing plant N status in greenhouse environments, although temperature-induced physiological changes should be accounted for in their interpretation.
Open Access
Parameters optimization of short carbon fiber-reinforced polyamide 6 printed using Big Area Additive Manufacturing (BAAM)
(Springer, 2025-05-29) Ramiro, Pedro; Penalva Oscoz, Mariluz; Suárez, Alfredo; Bengoa, Pablo; Goenaga, Borja; Gkournelos, Christos; Veiga Suárez, Fernando; Gómez, Gaizka; Ingeniería; Ingeniaritza
Big Area Additive Manufacturing (BAAM) of thermoplastic polymers is increasingly adopted for components, tooling and, especially, moulds across various industries and sectors as aerospace, automotive, energy, marine or construction due to its high productivity and low investment costs. However, geometric accuracy, layer adhesion and anisotropic properties of 3D printed parts are the main detrimental aspects for the successful implementation of this technology in the industry. As 3D printed parts need to withstand similar loads and stresses as those manufactured by traditional methods to be viable in industrial and engineering applications, enhancing mechanical properties ensures that parts do not break or deform under normal use. In this study, the effects of the main process parameters in the geometry distortion, inner defects and interfacial adhesion of 20% carbon fiber-reinforced polyamide 6 printed by pellet extrusion BAAM were determined, and the optimal process window was identified in terms of substrate deposition temperature, layer height and extruder motor rotation. With optimal parameters, the voids formed inbetween deposited beads were removed and the mechanical performance at room temperature in the z-direction compared to the bead direction was highly improved to 42% and 35% for tensile strength and modulus, respectively. It means a significant enhancement compared to the results reported by the state of the art, which show average values below 25%, and a highly notable improvement of the mechanical properties in the z-direction.
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 Publikoa
Additive 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.
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 Publikoa
Obtaining 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.
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-UPNA12514
Surface 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).
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 Gobernua
Red 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.
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 Gobernua
Consumers' 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.
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 - ISC
The 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.
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 Lana
En 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.
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 - ISC
The 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.
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 - INAMAT2
The 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.
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 - ISC
Additive 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.
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 Gobernua
The 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.
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 Publikoa
In 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.
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 Publikoa
Fastening 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.
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 - ISC
This 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.
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 Publikoa
In 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.