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Publication Open Access Impact of geometric and hemodynamic changes on a mechanobiological model of atherosclerosis(Elsevier, 2024) Hernández-López, Patricia; Cilla, Myriam; Martínez, Miguel Ángel; Peña, Estefanía; Malvè, Mauro; Ingeniería; IngeniaritzaBackground and objective: in this work, the analysis of the importance of hemodynamic updates on a mechanobiological model of atheroma plaque formation is proposed. Methods: for that, we use an idealized and axisymmetric model of carotid artery. In addition, the behavior of endothelial cells depending on hemodynamical changes is analyzed too. A total of three computational simulations are carried out and their results are compared: an uncoupled model and two models that consider the opposite behavior of endothelial cells caused by hemodynamic changes. The model considers transient blood flow using the Navier-Stokes equation. Plasma flow across the endothelium is determined with Darcy's law and the Kedem-Katchalsky equations, considering the three-pore model, which is also employed for the flow of substances across the endothelium. The behavior of the considered substances in the arterial wall is modeled with convection¿diffusion¿reaction equations, and the arterial wall is modeled as a hyperelastic Yeoh's material. Results: significant variations are noted in both the morphology and stenosis ratio of the plaques when comparing the uncoupled model to the two models incorporating updates for geometry and hemodynamic stimuli. Besides, the phenomenon of double-stenosis is naturally reproduced in the models that consider both geometric and hemodynamical changes due to plaque growth, whereas it cannot be predicted in the uncoupled model. Conclusions: the findings indicate that integrating the plaque growth model with geometric and hemodynamic settings is essential in determining the ultimate shape and dimensions of the carotid plaque.Publication Open Access Cátedra Mujer, Ciencia y Tecnología de la UPNA(Gobierno de Navarra, 2023) Aranguren Garacochea, Patricia; Barrenechea Tartas, Edurne; Catalán Ros, Leyre; Díaz Lucas, Silvia; Jurío Munárriz, Aránzazu; Martínez Ramírez, Alicia; Millor Muruzábal, Nora; Gómez Fernández, Marisol; San Martín Biurrun, Idoia; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Institute for Advanced Materials and Mathematics - INAMAT2La Cátedra Mujer, Ciencia y Tecnología de la Universidad Pública de Navarra (UPNA) tiene como objetivo aumentar la participación de las mujeres en campos de ciencia y tecnología. La cultura y la divulgación científicas son el eje principal de la actividad de la Cátedra. Dicha actividad engloba: la representación teatral Yo quiero ser científica, talleres experimentales y conferencias y exposiciones para todos los públicos y edades. Más de 6000 personas han visto la obra de teatro, más de 1500 estudiantes de ESO han participado en los talleres y el material audiovisual ha recibido más de 20000 visitas.Publication Open Access Experimental and computational investigation of passive heat exchangers to enhance the performance of a geothermal thermoelectric generator(Elsevier, 2024) Pascual Lezaun, Nerea; Alegría Cía, Patricia; Araiz Vega, Miguel; Martínez Echeverri, Álvaro; Astrain Ulibarrena, David; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISCThermoelectric devices hold significant promise for generating electricity from geothermal heat, enabling the powering of measuring equipment in remote locations without the need for moving parts. Nevertheless, most developed geothermal thermoelectric generators employ fans and pumps to enhance heat transfer, thereby compromising the robustness and reliability inherent to thermoelectricity. Furthermore, there is a lack of research on passive heat exchangers for geothermal thermoelectric generators, particularly in studying their operation under a wide range of meteorological conditions. Therefore, this paper conducts a comprehensive analysis of passive heat exchangers for the cold side of the generators. Phase-change-based heat exchangers differing in their length and fluid are studied experimentally, along with a fin dissipator. Additionally, the influence of wind velocity on heat transfer and mechanical requirements is further explored through a Computational Fluid Dynamics model. The most significant outcome is quantifying the impact of the design parameters and operational variables on the electrical production of the thermoelectric generator. Accordingly, this research aims to broaden the application of these generators to extreme environments, such as Deception Island in Antarctica. Under average operational conditions, generators incorporating 400 mm water heat pipes generate 0.95 W per thermoelectric module, while those incorporating heat pipes with methanol achieve an average of 0.70 W. Moreover, water and methanol-based systems produce 120% and 60% more power than generators using a fin dissipator. Nonetheless, for temperatures beyond -6.5 °C, water might freeze and the methanol-based heat exchangers become more suitable.Publication Open Access Study and optimization of the punching process of steel using the Johnson-Cook damage model(2024) Claver Alba, Adrián; Hernández Acosta, Andrea; Barba Areso, Eneko; Fuertes Bonel, Juan Pablo; Torres Salcedo, Alexia; García Lorente, José Antonio; Luri Irigoyen, Rodrigo; Salcedo Pérez, Daniel; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2Sheet metal forming processes are widely used in applications such as those in the automotive or aerospace industries. Among them, punching is of great interest due to its high productivity and low operating cost. However, it is necessary to optimize these processes and adjust their parameters, such as clearance, shear force or tool geometry, to obtain the best finishes and minimize crack generation. Thus, the main objective of this research work is to optimize the punching process to achieve parts that do not require subsequent processes, such as deburring, by controlling the properties of the starting materials and with the help of tools such as design of experiments and simulations. In the present study, tensile tests were performed on three steels with different compositions and three sample geometries. The information obtained from these tests has allowed us to determine the parameters of the Johnson-Cook damage criteria. Moreover, punching was performed on real parts and compared with simulations to analyze the percentage of burnish surface. The results obtained show that the methodology used was correct and that it can be extrapolated to other types of die-cutting processes by reducing the percentage of surface fractures and predicting the appearance of cracks. Furthermore, it was observed that clearance has a greater influence than processing speed, while the minimum percentage of the burnish area was observed for the minimum values of clearance.Publication Open Access The integration of mechanical energy absorbers into rollover protective structures to improve the safety of agricultural tractors in the event of rollover(MDPI, 2024) Alfaro López, José Ramón; Pérez Ezcurdia, Amaya; Latorre Biel, Juan Ignacio; Arana Navarro, Ignacio; Benito Amurrio, Marta; Villanueva Roldán, Pedro; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA1912The combination of safety belts and rollover protective structures (ROPSs) is key in improving the safety of agricultural tractors in the event of rollover. However, we also have the opportunity to enhance the security provided by each ROPS; one such example is the combination of this safety device with adequate mechanical energy absorbers (MEAs). Inexpensive disc-shaped MEAs can be included in the anchoring points of a ROPS onto the chassis of a tractor. Three configurations of ROPS combined with MEAs were tested during the application of loads that simulated the effects of side rollover in the vehicle. The tested configurations included a blank MEA as a reference case alongside a single MEA and a stack assembly containing both elements. The results of the tests show that both the deformation of the ROPS itself and the strain energy are larger in the case of blank MEAs; thus, there is also a risk that the clearance zone will be infringed upon and that the protective structure will collapse. We can conclude that the implementation of an appropriate MEA in ROPS reduces the deformation of the ROPS itself and its strain energy in cases of vehicle rollover; hence, the safety provided by such protection systems may be improved at a low cost.Publication Open Access Optical fiber sensor for water velocity measurement in rivers and channels(Nature Research, 2024) Rodríguez Rodríguez, Armando; Diéguez Elizondo, Pedro; Urroz Unzueta, José Carlos; Bravo Acha, Mikel; López Rodríguez, José Javier; López-Amo Sáinz, Manuel; Ingeniería; Ingeniaritza; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISCIn this work, optical fiber Bragg grating sensors were used to measure water velocity and examine how it was distributed in open channels. Several types of coatings were incorporated into the design of the sensors to examine their effects on the strain that the fibers experienced as a result of the water flow. Due to their low elastic coefficient, which reduced the hysteresis, the results indicated that the aluminum- and acrylate-coated fibers had the best performance. ANSYS-CFX V2020 R2 software was used to model the strain encountered by the fibers under various flow rates to assess the performance of the FBG sensors. The calculations and actual data exhibited good convergence, demonstrating the accuracy of the FBG sensors in determining water velocity. The study illustrated the usability of the proposal in both scenarios by contrasting its application in rivers and channels.Publication Open Access Harnessing the potential of radiative cooling for the built environment: a new comprehensive protocol for materials' characterization(Elsevier, 2024-07-26) Chiatti, Chiara; Marchini, Francesco; Fabiani, Claudia; Kousis, Ioannis; Carlosena Remírez, Laura; Pisello, Anna Laura; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISCThe pursuit of novel materials for radiative cooling (RC) holds immense promise in addressing building energy saving and urban overheating. RC capitalizes on the principle of dissipating heat energy into space, specifically through the atmospheric window between 8-13 μm, to achieve passive cooling of surfaces. However, the absence of a standardized and reliable methodology for characterizing RC materials has introduced inconsistencies in research findings, impeding collective advancements in the field. To address this issue, a dedicated experimental protocol is here introduced, as a unifying benchmark for the characterization of RC materials. This procedure aims to provide comprehensive, consistent, and precise data regarding crucial properties of RC cooling materials, including thermal stability, spectral radiative behavior, and thermal performance under both controlled and realistic boundary conditions. To demonstrate the effectiveness of our proposed methodology, we designed and implemented a comparative study involving an aluminum-based and a Vikuiti-based sample incorporating a silica-derived polymer as an emissive layer. Notably, our findings reveal that the Vikuiti prototype outperforms the aluminum counterpart, primarily attributable to its superior solar reflectance and thermal emittance characteristics. This research not only advances our understanding of RC materials but also offers a crucial step toward uniform characterization methods that can catalyze further research and scaling up of radiative cooling technologies.Publication Open Access Design and experimentation of a hydrokinetic turbine for electricity generation in closed pipes(World Scientific and Engineering Academy and Society, 2024) Armañanzas Goñi, Javier; Alcalá, Marina; Fuertes Bonel, Juan Pablo; León Iriarte, Javier; Torres Salcedo, Alexia; Gil Liberal, Miguel; Ingeniería; IngeniaritzaIn the present research work, a device for electrical energy generation to be used in water pipelines has been designed, simulated, and tested. To achieve this, a study of the most influential parameters involved in the experiment has been carried out and both, the turbine model and the geometry of the experimental test pipe, have been selected through CFD simulations. Next, the Design of Experiments (DOE) has been used to obtain the configuration with a higher energy extraction from running water. Finally, the turbine and the test pipe section have been manufactured by 3D printing and the experimental tests have been carried out with the optimal configuration to validate the results obtained in the CFD simulations. To simulate the exchange of energy between the water and the turbine, the CFD software SIMULIA XFlow has been used.Publication Open Access Validation of the use of concept maps as an evaluation tool for the teaching and learning of mechanical and industrial engineering(Springer, 2024) Veiga Suárez, Fernando; Gil del Val, Alain; Iriondo, Edurne; Eslava Adot, Urko; Ingeniería; Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaThis paper presents the experimental work developed to measure the learning process through concept map analysis. The development of a concept map is requested by the students for each chapter or theme of the subject. As a result, maps from engineering courses have been analyzed. The measurements carried out consider several parameters, such as individual and team map building, student progressive knowledge level, and map complexity. Concerning the complexity analysis, the focus is qualitative, and it is based on the data extracted from the concept maps elaborated by the students. The study, conducted during the 2018-2019 academic year, included students from various academic levels and institutions, such as the Public University of Navarra UPNA and the University of the Basque Country UPV-EHU, covering first-degree students of Bachelor's Degree in Mechanical Engineering and first-degree students of Master's Degree in Industrial Engineering at UPNA, third-degree students of Bachelor's Degree in Mechanical Engineering at UPV-EHU. The data collected from 37 individual maps in Industrial Drawing, 31 group maps in Industrial Drawing, 12 individual maps in Design of Machinery, and 12 group maps in Design of Machinery, along with a control group of 79 students who did not participate in any activity, provided valuable insights into the effectiveness of concept maps for evaluating understanding levels and learning outcomes across various engineering subjects and academic levels. The learning outcome of the students is treated to obtain the level of understanding of complex systems shown by the students through the concept maps previously drawn and the questionnaire answered by each student about the achievement of learning results through the use of concept maps. This work shows the research methodology established and the learning results achieved qualitatively: measuring the maps by means of a rubric, self-assessment based on a survey, and through the questionnaires. Also, the results obtained in the final exams have been compared. From the observed results, this methodology is presented as a suitable alternative for evaluating the correct acquisition of concepts in online teaching situations.Publication Open Access Thermoelectrics working in favour of the natural heat flow to actively control the heat dissipation(Elsevier, 2024) Alzuguren Larraza, Iñaki; Aranguren Garacochea, Patricia; Casi Satrústegui, Álvaro; Erro Iturralde, Irantzu; Rodríguez García, Antonio; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaIn sectors such as electronics, photonics and HVAC and refrigeration, heat dissipation has a major impact in their performance. However, there is generally not much control over this effect. Thus, one way of making these units more controllable would be to include thermoelectric technology in the heat dissipation systems. Therefore, in this work, a computational model based on the resistance-capacitance model to solve a thermoelectrically aided heat dissipation system is proposed, considering all the thermoelectric effects, temperature dependent thermoelectric properties and four temperature levels. Besides, an experimental prototype has been built to assess the real performance of thermoelectric modules (TEM) working under different operating conditions. Additionally, these results have been used to validate the computational model, obtaining maximum errors of ±6% in the main parameters. Moreover, the computational model has been used to simulate the effect of modifying the temperature difference between the hot and cold sources and the thermal resistances of the heatsinks located on both sides of the TEMs. The results show that the thermoelectrically aided dissipation system would be beneficial when working with low temperature differences and low thermal resistance values of the heatsinks, especially on the heatsink located on the hot side of the TEMs.Publication Open Access Low-frequency electromagnetic harvester for wind turbine vibrations(Elsevier, 2024) Castellano Aldave, Jesús Carlos; Plaza Puértolas, Aitor; Iriarte Goñi, Xabier; Carlosena García, Alfonso; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaIn this paper we describe and fully characterize a novel vibration harvester intended to harness energy from the vibration of a wind turbine (WT), to potentially supply power to sensing nodes oriented to structural health monitoring (SHM). The harvester is based on electromagnetic conversion (EM) and can work with vibrations of ultra-low frequencies in any direction of a plane. The harvester bases on a first prototype already disclosed by the authors, but in this paper, we develop an accurate model parameterized by a combination of physical parameters and others related to the geometry of the device. The model allows predicting not only the power generation capabilities, but also the kinematic behaviour of the harvester. Model parameters are estimated by an identification procedure and validated experimentally. Last, the harvester is tested in real conditions on a wind turbine.Publication Open Access Analysis of the machining process of short carbon fiber-reinforced polyamide additive manufactured parts(Elsevier, 2024) Suárez, Alfredo; Veiga Suárez, Fernando; Penalva Oscoz, Mariluz; Ramiro, Pedro; Ballesteros Egüés, Tomás; Ingeniería; IngeniaritzaIn recent years, additive manufacturing technologies have revolutionized the production of parts, particularly in the aeronautical sector. This new manufacturing paradigm has created significant challenges and opportunities for researchers in materials and manufacturing processes. One important aspect is the development of optimal strategies for finishing-oriented machining of parts produced through additive manufacturing. This article focuses on the analysis of reinforced polyamide materials and the integration of large-scale additive manufacturing using Big Area Additive Manufacturing (BAAM) technology, along with robotic systems for subtractive machining. The aim is to explore the potential of integrating additive and subtractive processes to produce high-quality, large-scale components. The study examines the production and subsequent machining of reinforced polyamide parts using BAAM technology, showcasing the advantages and promising results observed. By combining additive manufacturing with subtractive machining, this research contributes to the ongoing advancements in the field of manufacturing, particularly in relation to reinforced polyamide materials. The findings presented in this article shed light on the potential of integrating additive and subtractive processes in the manufacturing industry, paving the way for more efficient and high-quality production methods.Publication Open Access Icephobic coating based on novel SLIPS made of infused PTFE fibers for aerospace application(MDPI, 2024) Vicente Gómara, Adrián; Rivero Fuente, Pedro J.; Rehfeld, Nadine; Stake, Andreas; García, Paloma; Carreño, Francisco; Mora, Julio; Rodríguez Trías, Rafael; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA1929The development of slippery surfaces has been widely investigated due to their excellent icephobic properties. A distinct kind of an ice-repellent structure known as a slippery liquid-infused porous surface (SLIPS) has recently drawn attention due to its simplicity and efficacy as a passive ice-protection method. These surfaces are well known for exhibiting very low ice adhesion values (τice < 20 kPa). In this study, pure Polytetrafluoroethylene (PTFE) fibers were fabricated using the electrospinning process to produce superhydrophobic (SHS) porous coatings on samples of the aeronautical alloy AA6061-T6. Due to the high fluorine–carbon bond strength, PTFE shows high resistance and chemical inertness to almost all corrosive reagents as well as extreme hydrophobicity and high thermal stability. However, these unique properties make PTFE difficult to process. For this reason, to develop PTFE fibers, the electrospinning technique has been used by an PTFE nanoparticles (nP PTFE) dispersion with addition of a very small amount of polyethylene oxide (PEO) followed with a sintering process (380 °C for 10 min) to melt the nP PTFE together and form uniform fibers. Once the porous matrix of PTFE fibers is attached, lubricating oil is added into the micro/nanoscale structure in the SHS in place of air to create a SLIPS. The experimental results show a high-water contact angle (WCA) ≈ 150° and low roll-off angle (αroll-off) ≈ 22° for SHS porous coating and a decrease in the WCA ≈ 100° and a very low αroll-off ≈ 15° for SLIPS coating. On one hand, ice adhesion centrifuge tests were conducted for two types of icing conditions (glaze and rime) accreted in an ice wind tunnel (IWT), as well as static ice at different ice adhesion centrifuge test facilities in order to compare the results for SHS, SLIPs and reference materials. This is considered a preliminary step in standardization efforts where similar performance are obtained. On the other hand, the ice adhesion results show 65 kPa in the case of SHS and 4.2 kPa of SLIPS for static ice and <10 kPa for rime and glace ice. These results imply a significant improvement in this type of coatings due to the combined effect of fibers PTFE and silicon oil lubricant.Publication Open Access The use of virtual sensors for bead size measurements in wire-arc directed energy deposition(MDPI, 2024) Fernández Zabalza, Aitor; Veiga Suárez, Fernando; Suárez, Alfredo; Alfaro López, José Ramón; Ingeniería; IngeniaritzaHaving garnered significant attention in the scientific community over the past decade, wire-arc directed energy deposition (arc-DED) technology is at the heart of this investigation into additive manufacturing parameters. Singularly focused on Invar as the selected material, the primary objective revolves around devising a virtual sensor for the indirect size measurement of the bead. This innovative methodology involves the seamless integration of internal signals and sensors, enabling the derivation of crucial measurements sans the requirement for direct physical interaction or conventional measurement methodologies. The internal signals recorded, the comprising voltage, the current, the energy from the welding heat source generator, the wire feed speed from the feeding system, the traverse speed from the machine axes, and the temperature from a pyrometer located in the head were all captured through the control of the machine specially dedicated to the arc-DED process during a phase of optimizing and modeling the bead geometry. Finally, a feedforward neural network (FNN), also known as a multi-layer perceptron (MLP), is designed, with the internal signals serving as the input and the height and width of the bead constituting the output. Remarkably cost-effective, this solution circumvents the need for intricate measurements and significantly contributes to the proper layer-by-layer growth process. Furthermore, a neural network model is implemented with a test loss of 0.144 and a test accuracy of 1.0 in order to predict weld bead geometry based on process parameters, thus offering a promising approach for real-time monitoring and defect detection.Publication Open Access Hydrogen gas-grilling in meat: impact on odor profile and contents of polycyclic aromatic hydrocarbons and volatile organic compounds(MDPI, 2024) Beriain Apesteguía, María José; Gómez Bastida, Inmaculada; García Murillo, Susana; Urroz Unzueta, José Carlos; Diéguez Elizondo, Pedro; Ibáñez Moya, Francisco C.; Ingeniería; Ingeniaritza; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Ciencias; ZientziakThe effect of fuel (hydrogen vs. butane) on the formation of volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) was evaluated for grilled horse meat (very low-fat and low-fat) cooking vertically. Gas chromatography-mass spectrometry was used to analyze PAHs and VOCs. An electronic nose was used to evaluate the odor profile. Total high-molecular-weight PAHs ranged from 19.59 to 28.65 µg/kg with butane and from 1.83 to 1.61 µg/kg with hydrogen. Conversely, total low-molecular-weight PAHs went from 184.41 to 286.03 µg/kg with butane and from 36.88 to 41.63 µg/kg with hydrogen. Aldehydes and alkanes were the predominant family in a total of 59 VOCs. Hydrogen gas-grilling reduced significantly (p < 0.05) the generation of VOCs related to lipid oxidation. The odor profile was not modified significantly despite the change of PAHs and VOCs. The findings indicate that hydrogen is a viable alternative to butane for grilling horse meat. Hydrogen gas-grilling may be regarded as a safe cooking procedure of meat from a PAH contamination point and perhaps sustainable environmentally compared to a conventional technique. The present study provides the basis for the use of hydrogen gas in grilled meat.Publication Open Access Usability and user expectations of a HoloLens-based augmented reality application for learning clinical technical skills(Springer, 2024) Escalada Hernández, Paula; Soto Ruiz, María Nelia; Ballesteros Egüés, Tomás; Larráyoz Jiménez, Ana; San Martín Rodríguez, Leticia; Ciencias de la Salud; Osasun Zientziak; Institute of Smart Cities - ISC; Ingeniería; Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaThe application of augmented reality in training health science students is increasingly widespread. The aim of this work was to assess the usability and user expectations of an augmented reality application for smart glasses (Microsoft HoloLens) that can be used to train on four invasive procedures (i.e. intramuscular injection, nasogastric tube insertion, endotracheal intubation and suctioning via tracheostomy tube). A descriptive study was conducted with nursing students from three Spanish universities. Participants answered a questionnaire to assess the use of the ARSim2care application. This application offers the possibility of visualizing the internal anatomical structures during the training of the clinical technical skills for the performance of the mentioned invasive techniques. The questionnaire included demographic data, the System Usability Scale and questions about the user expectations in relation to learning with the use of augmented reality. In total, 61 participants responded to the questionnaire after using the ARSim2care application. The mean score of the System Usability Scale was 73.15 (standard deviation: 15.04) and 62.4% (n = 38) of the participants considered their experience with the application as excellent or good. In relation to user expectations, more than 90% of students indicated that the use of the application could improve their motivation and stimulation in learning, their content retention and their anatomical understanding. The developed ARSim2care application for Microsoft HoloLens showed a high level of usability and acceptance as a learning tool for training certain clinical procedures by visualizing the internal structures of the body.Publication Open Access Cognitive systems for the energy efficiency industry(MDPI, 2024) Arévalo Royo, Javier; Latorre Biel, Juan Ignacio; Flor Montalvo, Francisco Javier; Pérez-Parte, Mercedes; Blanco Fernández, Julio; Ingeniería; IngeniaritzaThis review underscores the pivotal role of Cognitive Systems (CS) in enhancing energy efficiency within the industrial sector, exploring the application of sophisticated algorithms, data analytics, and machine learning techniques to the real-time optimization of energy consumption. This methodology has the potential to reduce operational expenses and further diminish environmental repercussions; however, it also leverages data-driven insights and predictive maintenance to foresee equipment malfunctions and modulate energy utilization accordingly. The viability of integrating renewable energy sources is emphasized, supporting a transition towards sustainability. Furthermore, this research includes a bibliometric literature analysis from the past decade on the deployment of CS and Artificial Intelligence in enhancing industrial energy efficiency.Publication Open Access Development and experimental validation of a two-stage thermoelectric heat pump computational model for heating applications(Elsevier, 2024) Erro Iturralde, Irantzu; Aranguren Garacochea, Patricia; Martínez Echeverri, Álvaro; Astrain Ulibarrena, David; Ingeniería; Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra - Nafarroako Unibertsitate PublikoaThe utilisation of thermoelectric technology as a heat pump in heating applications necessitates comprehensive investigation. The scalable nature of thermoelectric technology enables its operation at elevated temperatures without the requirement of refrigerants. In this work, an accurate computational model that can simulate one- and two-stage thermoelectric heat pumps is developed. This model uses the electric-thermal analogy and the finite difference method, including the thermoelectric effects, temperature dependent properties, thermal contact resistances and all heat exchangers, even the intermediate heat exchanger in the case of a two-stage configuration. Moreover, the model has been experimentally validated by built and tested prototypes, being the first time that a two-stage thermoelectric heat pump model is experimentally validated. The discrepancy between the simulated and experimental results is below the ± 10 % for , ± 8 % for generated heat and temperature lift in the airflow, and less than the ± 6 % for consumed power. Additonally, the model simulates real tendencies under different operating conditions, proving the reliability of the developed thermoelectric heat pump model. Finally, the model is used to optimise a thermoelectric system combining one- and two-stage thermoelectric heat pumps, and hybridising them with electric resistances. An airflow of 16.5 m3/h is heated from 25 °C to 160 °C, achieving a maximum of 1.21. Lastly, the importance of considering the thermal resistances of the heat exchangers is computationally modelled and demonstrated. Not taking them into account would overestimate the performance of the TEHP system by more than the 7 %.Publication Open Access An antibacterial submicron fiber mat with in situ synthesized silver nanoparticles(Wiley, 2012) Rivero Fuente, Pedro J.; Urrutia Azcona, Aitor; Goicoechea Fernández, Javier; Rodríguez, Yoany; Corres Sanz, Jesús María; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2This work presents an alternative approachfor fabricating electrospun submicron highly hydrophilicfiber mats loaded with silver nanoparticles. These fiber matsshow a high efficient antibacterial behavior, very attractivefor applications like wound healing and skin regenerationprocesses. The fabrication method is divided in two steps.First, poly(acrylic acid) (PAA) and b-cyclodextrin (b-CD)submicron fibers were electrospun and further stabilizedusing a thermal treatment, yielding stable hydrogel-likefibers with diameters ranging from 100 nm up to severalmicrons. In the second step, silver ions were loaded into thefibers and then reduced to silver nanoparticles in-situ. Theelectrospinning parameters were adjusted to achieve thedesired properties of the fiber mat (density, size) and after-wards, the characteristics of the silver nanoparticles(amount, size, aggregation) were tuned by controlling thesilver ion loading mechanism. Highly biocide surfaces wereachieved showing more than 99.99% of killing efficiency.The two-step process improves the reproducibility and tun-ability of the fiber mats. To our knowledge, this is the firsttime that stable hydrogel fibers with a highly biocide behav-ior have been fabricated using electrospinning.Publication Open Access Electrospun nanofiber mats for evanescent optical fiber sensors(Elsevier, 2013) Urrutia Azcona, Aitor; Goicoechea Fernández, Javier; Rivero Fuente, Pedro J.; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaIn this work, a study about the optical response of electrospun nanofiber (ENF) coatings for their use in evanescent optical fiber sensors is presented. Several types of ENF mats composed of poly(acrylic acid) (PAA) were developed with different ENF diameters and densities. These ENF mats were deposited onto an optical fiber core in order to fabricate humidity evanescent optical fiber sensors. The devices were exposed to relative humidity (RH) variations from 30% RH to 95%RH. The transfer functions of the devices (transmitted optical power versus relative humidity) presented two well-differenced behaviors depending on the ENF diameter and the ENF mat density. The devices with lower ENF diameters and higher mat density showed an increase in the transmitted optical power when RH increased. On the contrary, the devices with higher ENF diameters and lower mat density showed a decrease in the transmitted optical power when RH increased. In addition to this, sensors with thinner ENF overlays, showed a higher sensitivity. In order to study the response time of these devices, the ENFs sensors were submitted to human breathing cycles and presented a response time around 340 ms (exhalation). In spite of the high RH conditions of this experiment, the devices showed a recovery time around 210 ms and a negligible hysteresis or drift with respect to the initial condition (inhalation).