Person:
Sevilla Moróder, Joaquín

person.page.identifierURI

https://academica-e.unavarra.es/handle/2454/50037

Last Name

Sevilla Moróder

First Name

Joaquín

person.page.departamento

Ingeniería Eléctrica, Electrónica y de Comunicación

person.page.instituteName

ISC. Institute of Smart Cities

ORCID

0000-0002-9052-0805

person.page.upna

1624

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Now showing 1 - 10 of 11

Open Access
Shear based gap control in 2D photonic quasicrystals of dielectric cylinders
(Optica, 2021) Andueza Unanua, Ángel María; Sevilla Moróder, Joaquín; Pérez Conde, Jesús; Wang, Kang; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Zientziak; Institute of Smart Cities - ISC; Institute for Advanced Materials and Mathematics - INAMAT2; Ingeniería Eléctrica, Electrónica y de Comunicación; Ciencias
2D dielectric photonic quasicrystals can be designed to show isotropic band gaps. In this work we study a quasiperiodic lattice made of silicon dielectric cylinders (ε = 12) arranged as periodic unit cell based on a decagonal approximant of a quasiperiodic Penrose lattice. We analyze the bulk properties of the resulting lattice as well as the bright states excited in the gap, which correspond to localized resonances of the electromagnetic field in specific cylinder clusters of the lattice. Then we introduce a controlled shear deformation γ which breaks the decagonal symmetry and evaluate the width reduction of the gap together with the evolution of the resonances, for all shear values compatible with physical constraints (cylinder contact). The gap width reduction reaches 18.5% while different states change their frequency in several ways. Realistic analysis of the actual transmission of the electromagnetic radiation, often missing in the literature, has been performed for a finite 'slice' of the proposed quasicrystals structure. Two calculation procedures based on MIT Photonic Bands (MPB) and Finite Integration Technique (FIT) are used for the bulk and the finite structures showing an excellent agreement between them.
Open Access
Experimental development and testing of low-cost scalable radiative cooling materials for building applications
(Elsevier, 2021) Carlosena Remírez, Laura; Andueza Unanua, Ángel María; Torres, Luis; Irulegi, Olatz; Hernández-Minguillón, Rufino J.; Sevilla Moróder, Joaquín; Santamouris, Mattheos; Ingeniaritza; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua
Urban overheating has a serious impact on building energy consumption. Daytime radiative cooling materials are an interesting passive solution for refrigeration. However, their costs and complex manufacturing hinder their current application. In this study, a series of scalable and lowcost daytime radiative cooling (DTRC) materials were designed, fabricated, and tested in a moderate climate (Cfb-Köppen-Geiger classification) and compared to aluminum and Vikuiti. The methodology was: i) material selection and design, (ii) optimization, (iii) fabrication, (iv) characterization, and (v) testing. The materials were fabricated using different substrates, aluminum and Vikuiti, and two kinds of formulations for the emissive layers based on silica-derived polymer polymethylsilsesquioxane (PMSQ) with embedded silica nanoparticles. The resulting aluminum DTRC materials had a mean solar reflectivity of 0.7 and 0.34 emissivity in the atmospheric window, the samples with Vikuiti had 0.97 and 0.89, respectively. During the experiment, the samples were exposed to different ambient conditions without a convection barrier and were contained in an extruded polystyrene board to eliminate conduction. The samples reached 7.32 °C and 9.13 °C maximum surface temperature reduction (below ambient) during the day and night, respectively. The samples with the commercial substrate achieved a mean reduction of 3.72 °C below ambient temperature. Although the aluminum samples did not achieve subambient cooling throughout the entire day, the emissive layer reduced the sample's surface temperature by an average of 1.7 °C. The PMSQ radiative cooling materials show great potential for future building applications. Suitability under different climates and experimental settings should be done to test broad applicability.
Open Access
Strain sensing based on resonant states in 2D dielectric photonic quasicrystals
(Optica, 2021) Andueza Unanua, Ángel María; Pérez Conde, Jesús; Sevilla Moróder, Joaquín; Zientziak; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Ingeniería Eléctrica, Electrónica y de Comunicación
This paper reports the numerical and experimental study of the strain sensing effect of bidimensional quasiperiodic structures made with dielectric cylinders. Structures of around 100 cylinders arranged following a Penrose quasiperiodic disposition were simulated, built and measured, in different states of deformation. The selected quasiperiodic structure contains a symmetric decagonal ring resonator that shows two states in its photonic band gap. The frequency of these states varies linearly in opposite directions as the structure is axially deformed, becoming an interesting sensing principle that can be exploited to build optical strain gauges. As a proof of concept, centimeter-scale glass cylinder (εr=4.5) structures were fabricated and their transmission spectra were measured in the microwave range. The same structures were simulated using finite integration time domain showing a good agreement with the measurements. The sensitivity of the prototype built was 12.4 kHz/µε, very linear in a wide range. Therefore, we conclude that the states in the gap of the resonator rings of 2D quasicrystals can find an interesting application in optical strain gauge construction.
Open Access
Enhanced thermal performance of photovoltaic panels based on glass surface texturization
(Elsevier, 2021) Andueza Unanua, Ángel María; Pinto Fuste, Cristina Leyre; Navajas Hernández, David; Sevilla Moróder, Joaquín; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua
Photovoltaic module temperature is a detrimental parameter influencing the energy yield and the durability of photovoltaic systems. Among the passive strategies to reduce the operating temperature of solar cells, radiative cooling is receiving a lot of attention, as an effective mean to passively evacuate heat in systems. The existence of a wavelength window of atmospheric transparency (8–13 μm) allows sending heat to outer space. The functionalization of the glass that could help to limit or reduce the temperature of the solar cells is an interesting approach. In this paper, we explore the effect of glass surface patterns in its radiation performance, so that the radiation cooling effect could be enhanced. The study is based on numerical simulations, calculating the spectral emissivity of different geometrical configurations of structures on top of the glass. Different geometrical figures of micrometers in size have been tested to find an optimal emissivity response in the transparent atmospheric window. Periodical patterns based on cones, pyramids, or moth-eye shapes result in emissivity responses close to one along thermal wavelengths (8–25 μm) which increases the emitted power of the glass. However, when assessing the cooling power under sunlight, the evaluation wavelength band has to be expanded (0.3–25 μm). Here, we found that not all geometrical figures are effective for radiative cooling. Surfaces textured by holes and pyramids show a substantial cooling effect, providing an increase in cooling power over the flat glass ranging from 40 W/m2 to 110 W/m2 depending on the temperature of the solar devices.
Open Access
Transmission spectra changes produced by decreasing compactness of opal-like structures
(AIP Publishing, 2009) Andueza Unanua, Ángel María; Echeverría, R.; Morales Zimmermann, Paola Andrea; Sevilla Moróder, Joaquín; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Artificial opal-like structures based on spheres and colloidal particles have been fabricated in a controlled way, presenting optical band-gap properties in the optical frequency range. Nonclose packed artificial opals have also been fabricated and studied recently. In order to gain a better understanding of these phenomena, we have studied macroscopic models of nonclose packed fcc lattices using glass spheres (ε = 7) of 8 mm diameter, and measuring in the microwave region from 10 to 30 GHz. The results have shown a Bragg resonance tunable with filling factor of the opal, and a strong rejected band similar, also present in close packed samples, much less affected by compactness. The relation of this high order band with spheres single layer behavior is also discussed
Open Access
Gramática de las gráficas: pistas para mejorar las representaciones de datos
(Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, 2005) Sevilla Moróder, Joaquín; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
Periodistas, científicos, sociólogos, ingenieros, economistas... En multitud de profesiones nos encontramos con la necesidad de interpretar o de realizar gráficas. Las gráficas son elementos habituales en multitud de textos: periódicos, revistas, informes, publicaciones científicas, etc. Y no es de extrañar dado que constituyen un excelente método de comunicación de información cuantitativa. No es improbable, sin embargo, encontrar gráficas que no resultan adecuadas, que no se entienden o que transmitan impresiones equívocas. Del mismo modo que los textos están sujetos a una gramática que aprendemos desde pequeños en la escuela, las gráficas también disponen de una estructura, sólo que mucho menos formalizada y, que desde luego, no se enseña en la escuela. El objetivo de este texto es ofrecer unas guías muy simples, basadas en la analogía con la gramática del lenguaje, que ayuden a comprender y especialmente a realizar representaciones gráficas correctas. Está dirigido a todos los públicos, buscándose la máxima sencillez en las ideas, sin ninguna apoyatura matemática o lingüística. Del mismo modo, los ejemplos están tomados casi exclusivamente de periódicos, de forma que el contenido de las gráficas tampoco despiste de su forma, que es lo que se pretende analizar aquí.
Open Access
Combining radiative cooling and light trapping strategies for improved performance of PERC bifacial silicon solar cells
(Elsevier, 2023) Urdiroz Urricelqui, Unai; Itoiz Goñi, Iñigo; Sevilla Moróder, Joaquín; Andueza Unanua, Ángel María; Ingeniería; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute for Advanced Materials and Mathematics - INAMAT2; Institute of Smart Cities - ISC; Ingeniaritza; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This work investigates the impact of combining light trapping and radiative cooling on bifacial solar panels. While several techniques have been proposed to enhance the efficiency of solar panels, their combination can lead to suboptimal results. By numerically evaluating the light absorption and thermal balance of different panel configurations, we found that each side of the bifacial solar cell can be textured independently with a cross-effect of less than 4%. However, our results also indicate that improving visible light trapping can increase infrared absorption, leading to a heating effect that may offset the benefits of radiative cooling. These findings highlight the importance of balancing the factors that influence solar panel efficiency and provide quantitative insights that guide the development of more effective solar energy systems.
Open Access
Strong angular dependence of resonant states in 2D dielectric cylinder rings
(AIP Publishing, 2018) Andueza Unanua, Ángel María; Pérez Conde, Jesús; Sevilla Moróder, Joaquín; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Fisika; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Física
We investigate collective resonators made of dielectric cylinders assembled as two-dimensional regular octagons and decagons. These structures exhibit collective resonance states that change their intensity with the incident radiation angle. While most parts of the spectra present small or even null variation, one of these resonances presents high-sensitivity to the incidence angle. This strong variation is well characterized in terms of the electric field intensity distribution of a resonant state where all the cylinders show the lowest order Mie resonance and the neighbors alternate their polarities. The collective state is optimally excited when radiation impinges on a vertex of the polygonal arrangement of cylinders, while the response decreases to its minimum when the incident field hits an edge (two cylinders at the same time). The resonant state and its high dependence on the excitation incidence angle have been found in both octagonal and decagonal configurations for different dielectric permittivity values. In addition, the scalability of Maxwell equations warranties the same behavior if the whole system is downscaled to terahertz or optic frequencies. The study was performed by finite integration time domain calculations of scattering and transmission for different incidence angles. Experimental measures in the microwave range were taken from photonic molecule prototypes made of centimeter-scale glass cylinders (ϵ = 4.5). We find an overall excellent agreement between measurements and simulations. We propose that photonic molecules made of polygonal rings of dielectric cylinders are an ideal structure to build angle sensors using the strongly varying state that they present.
Open Access
Geometry influence on the transmission spectra of dielectric single layers of spheres with different compactness
(AIP Publishing, 2010) Andueza Unanua, Ángel María; Echeverría, R.; Morales Zimmermann, Paola Andrea; Sevilla Moróder, Joaquín; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
The transmission of spectra of different dielectric spheres single layer arrangements has been measured. High dielectric permittivity ε =7 spheres of several millimeters of diameter were used to build the samples whose transmission was measured in the microwave range. The behavior of lattices arranged in square and triangular geometries have been compared in a number of different compactness cases. The same patterns measured have also been calculated by finite-difference time-domain FDTD method. Spectra from different geometrical arrangements of the same compactness measured with the same filling fraction value are very similar in some cases. Based on the level of similarity we propose three compactness regions. The high compactness region, where the structure effect is important, presents spectra clearly different for the two geometries. In a medium compactness region spectra are almost identical, suggesting a dominant effect of single sphere effects. Finally, in the low compactness region, the spectra from the two geometrical configurations diverge again as the Bragg diffraction values are approached.
Open Access
Growth in the number of references in engineering journal papers during the 1972-2013 period
(Springer, 2014) Úcar Marqués, Iñaki; López Fernandino, Felipe; Rodríguez Ulibarri, Pablo; Sesma Sánchez, Laura; Urrea Micó, Verónica; Sevilla Moróder, Joaquín; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Automática y Computación; Automatika eta Konputazioa
The number of references per paper, perhaps the best single index of a journal’s scholarliness, has been studied in different disciplines and periods. In this paper we present a four decade study of eight engineering journals. A data set of over 70,000 references was generated after automatic data gathering and manual inspection for errors. Results show a significant increase in the number of references per paper, the average rises from 8 in 1972 to 25 in 2013. This growth presents an acceleration around the year 2000, consistent with a much easier access to search engines and documents produced by the generalization of the Internet.