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Solar concentrator systems represent an important challenge in our society for outstanding photovoltaic (PV) applications. Fresnel lenses or parabolic mirrors concentrate sunlight in a small solar cell surface. On the one hand, Fresnel lenses have an exceedingly small acceptance angle and require expensive tracking systems to follow the path of the Sun. On the other hand, conventional parabolic mirrors need periodic maintenance of the surface reflectivity. Holographic optical elements (HOEs) represent a suitable alternative to Fresnel lenses and solar reflectors, they are cheaper and more versatile. Particularly, multiplexed holographic solar concentrators (HSCs) give an insight into promising possibilities for Building-Integrated Concentrating PV (BICPV). A good trade-off between wide acceptance angle and high diffraction efficiency represents an important milestone in the area. Our research group obtained the higher acceptance angle in a multiplexed HSC design (Morales et. al. Opt. Express 30, 25366 (2022)). This design was composed of seven holographic multiplexed lenses in Biophotopol material with thick thickness, 197 μm. In the present work, more efficient holographic solar concentrators than previous works are shown. As far as we know, it has been obtained the best trade-off between high efficiency and wide acceptance angle HSC-PV solar cell systems. Generalitat Valenciana (CIDEXG/2022/60, IDIFEDER/2021/0.14, PROMETEO/2021/006); Ministerio de Ciencia e Innovación (PID2019-106601RB-I00; PID2021-123124OB-I00); Universidad de Alicante (UAFPU20-23).

Nowadays, the study and optimization of volume holographic lenses (HLs) stored in low-toxicity photopolymers have a great interest. HLs are now a component of optical imaging systems that are mostly used in head-mounted displays for virtual and augmented reality or as non-image systems in light deflectors and concentrators. One of the most important parameters used when working with imaging systems is the resolution of the optical system. In this work, the similarity between the object and image of negative asymmetrical HLs stored in a low-toxicity photopolymer named Biophotopol has been evaluated theoretically and experimentally. For this purpose, the resolution of the HLs was calculated using the Convolution Theorem. A USAF 1951 test was used as an object and the impulse responses of the HLs were obtained with two different sensors: CCD and Hartmann-Shack (HS) wavefront sensor. In addition, the resolution of the HLs has been obtained by two different methods: one using the Convolution Theorem, using both the CCD and the HS wavefront sensor, and the other by forming the USAF test image on the CCD sensor. Finally, a theoretical study of object-image similarity was carried out using the MSE (mean squared error) metric to evaluate the quantitative experimental results. This research was funded by Universidad de Alicante (UAFPU20-23); Generalitat Valenciana (CIDEXG/2022/60, IDIFEDER/2021/014, PROMETEO/2021/006); Ministerio de Ciencia e Innovación (PID2019-106601RB-I00, PID2021-123124OB-I00).

In the last few years, the interest in storing volume holograms in photopolymers has increased enormously due to their applications in industry, the medical field, security, or renewal energy among others. The production of environmentally compatible photopolymers is one of the main focuses of Holography research. In this work, we have studied how to increase the diffraction efficiency of reflection holograms stored in a low-toxicity PVA-based photopolymer called Biophotopol. The holographic material has been doped with different types of nanoparticles (NPs) to achieve an increase in the refractive index modulation during the recording stage. Metallic NPs, obtained by physical and electrochemical methods have been used. The results obtained with all of them have been compared as a function of the concentration used, the size of the NPs, and the stabilization method used for their synthesis. A considerable increase in diffraction efficiency has been achieved by using NPs in the low-toxicity material. By using high refractive index NPs, the average refractive index of the holographic material increases and consequently the diffraction efficiency. This research was funded by Generalitat Valenciana, Spain, under projects PROMETEO/2021/006, IDIFEDER/2021/014 (co-funded by European Union through the FEDER Program) and CIDEXG/2022/60; Universidad de Alicante, Spain, under project UAFPU20-23 and Ministerio de Ciencia e Innovación, Spain, under projects PID2019-106601RB-I00 and PID2021-123124OB-I00.

Photopolymers are designed and engineered with versatile applications including optics and photonics. Holography is one of the classical porpoises that use photopolymers as holographic recording materials. The success of these materials can be seen in the market with the photopolymer fabricated by Covestro. Some of these holographic applications require a long-time life of the holograms recorded in photopolymers. Nevertheless, initial tests of Covestro holograms show significant degradation after less than one year of exposure even after sealing and degradation occurs under solar light exposition. In this sense, it is important to perform deeper studies of the different possibilities for hologram conservation. Usually, the first step after recording is the material cure, with UV or visible light, to eliminate the residual dye and monomer. With this process high efficiency holograms can also be obtained. Afterwards, an index matching technique can be used to cover the material with a glass or it is possible the application of aerosol sealant. In this paper we analyze the introduction of holograms between two glasses linked by pressure, using Bayfol HX 200 from Covestro as the recording material. In order to characterize the process, four different spatial frequencies were tested, which were stored either by transmission or reflection schemes. The data of the reconstruction step has been measured before and after the encapsulation. In addition, multiple holograms have been superposed in the same glass, where we have found that shrinkage is more significant. The work was supported by the “Generalitat Valenciana” (Spain) project PROMETEO/2021/006 and by the ‘‘Universidad de Alicante’’ (UATALENTO18-10; ACIE-20-10). Generalitat Valenciana (Spain) (IDIFEDER/2021/014, cofunded by European Union through the FEDER Programme and “Ministerio de Ciencia e Innovación” of Spain (project PID2021-123124OB-I00).

[ES] Los humedales son uno de los ecosistemas más importantes del planeta. En los distintos hábitats que albergan convive un gran número de especies, siendo un reservorio de biodiversidad. Además, al ser sumideros de carbono (CO2, ) son un aliado natural en la lucha contra el cambio climático. Los humedales resultan imprescindibles para el cumplimiento de los objetivos de sostenibilidad de la Agenda 2030. Desgraciadamente, la desaparición de estos espacios naturales es alarmante, especialmente acelerada durante el siglo XX y lo que llevamos de siglo XXI. Uno de los motivos más importantes que causa su pérdida y degradación es la falta de recursos hídricos. En general, en situaciones de estrés hídrico, es necesario aportar agua procedente de fuentes externas. La elección de las fuentes de recursos hídricos supone un complejo problema de decisión. La calidad del agua debe ser la adecuada para garantizar la sostenibilidad del humedal. En esta tesis se elabora una metodología para resolver ese problema. Se ha aplicado al caso de las Tablas de Daimiel, pero puede ser utilizada en cualquier otro humedal. A partir de los valores de referencia del humedal se han elaborado unas funciones de rating que permiten asignar puntuación a los distintos valores de los parámetros fisicoquímicos. Hay una función de rating para cada uno de los parámetros. Las funciones son específicas del humedal cuya regeneración hídrica se pretende. Se ha asignado un peso a los distintos parámetros fisicoquímicos para considerar la diferente repercusión de cada uno de ellos en la calidad del agua. Para ello se ha llevado a cabo un análisis mediante el Analytical Hierarchical Process (AHP). Agregando las funciones de rating con los pesos obtenidos se ha diseñado un índice de sostenibilidad (WRSM). Las fuentes de agua más adecuadas toman valores más altos del índice, en contraposición con las menos aconsejables.Todo el proceso descrito se ha aplicado a las Tablas de Daimiel, comprobándose su utilidad y eficacia para evaluar diferentes tipos de aguas procedentes de muy diversas fuentes. La metodología desarrollada es novedosa, completamente reproducible y además es aplicable a cualquier otro humedal, por lo que puede constituir una nueva herramienta para abordar la importante y compleja tarea que supone la restauración hídrica de humedales., [CA] Els aiguamolls són un dels ecosistemes més importants del planeta. En els diferents hàbitats que alberguen conviu un gran nombre d'espècies, sent un *reservorio de biodiversitat. A més, en ser embornals de carboni (CO¿, ) són un aliat natural en la lluita contra el canvi climàtic. Els aiguamolls resulten imprescindibles per al compliment dels objectius de sostenibilitat de l'Agenda 2030. Desgraciadament, la desaparició d'aquests espais naturals és alarmant, especialment accelerada durant el segle XX i el que portem de segle XXI. Un dels motius més importants que causa la seua pèrdua i degradació és la falta de recursos hídrics. En general, en situacions d'estrés hídric, és necessari aportar aigua procedent de fonts externes. L'elecció de les fonts de recursos hídrics suposa un complex problema de decisió. La qualitat de l'aigua ha de ser l'adequada per a garantir la sostenibilitat de l'aiguamoll. En aquesta tesi s'elabora una metodologia per a resoldre aqueix problema. S'ha aplicat al cas de les Taules de Daimiel, però pot ser utilitzada en qualsevol altre aiguamoll. A partir dels valors de referència de l'aiguamoll s'han elaborat unes funcions de ràting que permeten assignar puntuació als diferents valors dels paràmetres fisicoquímics. Hi ha una funció de ràting per a cadascun dels paràmetres . Les funcions són específiques de l'aiguamoll la regeneració hídrica del qual es pretén. S'ha assignat un pes als diferents paràmetres fisicoquímics per a considerar la diferent repercussió de cadascun d'ells en la qualitat de l'aigua. Per a això s'ha dut a terme una anàlisi mitjançant el Analytical *Hierarchical *Process (*AHP). Agregant les funcions de ràting amb els pesos obtinguts s'ha dissenyat un índex de sostenibilitat (*WRSM). Les fonts d'aigua més adequades prenen els valors més alts de l'índex, en contraposició amb les menys aconsellables. Tot el procés descrit s'ha aplicat a les Taules de Daimiel, comprovant-se la seua utilitat i eficàcia per a avaluar diferents tipus d'aigües procedents de molt diverses fonts. La metodologia desenvolupada és nova, completament reproduïble i a més és aplicable a qualsevol altre aiguamoll, per la qual cosa pot constituir una nova eina per a abordar la important i complexa tasca que suposa la restauració hídrica d'aiguamolls., [EN] Wetlands are one of the most important ecosystems on the planet. A large number of species coexist in the different habitats that are home to wetlands. They are a reservoir of biodiversity. Furthermore, being carbon sinks (CO2, ), wetlands are a natural ally in the fight against climate change. Wetlands are essential to meet the sustainability goals of the 2030 Agenda. Unfortunately, the disappearance of these natural spaces is alarming, especially accelerated during the 20th century and so far in the 21st century. One of the most important reasons that causes its loss and degradation is the lack of water resources. In general, in situations of water stress, it is necessary to obtain water from external sources. The choice of sources of water resources is a complex decision problem. The quality of the water must be adequate to guarantee the sustainability of the wetland. This thesis develops a methodology to solve this problem. It has been applied to the case of the Tablas de Daimiel wetland, but it can be used in any other wetland. Based on the reference values of the wetland, qualification functions have been developed. These functions evaluate the physicochemical parameters. There is a rating function for each of the parameters. The functions are specific to the wetland whose water regeneration is intended. A weight has been assigned to the different physicochemical parameters to consider the different impact of each of them on water quality. For this, an analysis has been carried out using the Analytical Hierarchy Process (AHP). Adding the rating functions with the weights obtained, a sustainability index (WRSM) has been designed. The most suitable water sources take the highest values of the index, compared to the least recommended. The entire process described has been applied to the Tablas de Daimiel wetland, demonstrating its usefulness and effectiveness for evaluating different types of water from very diverse sources. The methodology developed is novel, completely reproducible and also applicable to any other wetland, so it can be a new tool to address the important and complex task of hydrological restoration in wetlands.

[EN] Acoustic holograms can encode complex wavefronts to compensate the aberrations of a therapeutical ultrasound beam propagating through heterogeneous tissues such as the skull, and simultaneously, they can generate diffraction-limited acoustic images, that is, arbitrary shaped focal spots. In this work, we numerically study the performance of acoustic holograms focusing at the thalamic nuclei when the source is located at the temporal bone window. The temporal window is the thinnest area of the lateral skull and it is mainly hairless, so it is a desirable area through which to transmit ultrasonic waves to the deep brain. However, in targeting from this area the bilateral thalamic nuclei are not aligned with the elongated focal spots of conventional focused transducers, and in addition, skull aberrations can distort the focal spot. We found that by using patient-specific holographic lenses coupled to a single-element 650-kHz-frequency 65-mm-aperture source, the focal spot can be sharply adapted to the thalamic nuclei in a bilateral way while skull aberrations are mitigated. Furthermore, the performance of these holograms was studied under misalignment errors between the source and the skull, concluding that for misalignments up to 5°, acoustic images are correctly restored. This work paves the way to designing clinical applications of transcranial ultrasound such as blood¿brain barrier opening for drug delivery or deep-brain neuromodulation using this low-cost and personalized technology, presenting desirable aspects for long-term treatments because the patient's head does not need to be shaved completely and skull heating is low., This research has been supported by the Spanish Ministry of Science, Innovation and Universities (MICINN) through Grants IJC2018-037897-I, FPU19/00601 and PID2019-111436RB-C22 and by the Agencia Valenciana de la Innovacion through Grant INNCON/2021/8. Action was co-financed by the European Union through the Programa Operativo del Fondo Europeo de Desarrollo Regional (FEDER) of the Comunitat Valenciana 2014-2020 (ID-IFEDER/2018/022 and IDIFEDER/2021/004)

[EN] The structurally simple complex {Fe-II[tren(6F-py)(3)]}(BF4)(2) [tren(6F-py)(3) = tris(3-aza-4-(6-fluoro-2-pyridyl)-3-butenyl)amine] undergoes an abrupt spin transition (ST) with the critical temperature T down arrow(1/2) = 243 K on cooling and T up arrow(1/2) = 281 K on heating, with a 38 K wide hysteresis, while the ClO4- congener shows ST spanning the room temperature region at T down arrow(1/2) = 267 K and T up arrow(1/2) = 295 K with a 28 K wide hysteresis. Calorimetric data confirm the occurrence of a highly energetic ST process, while multi-temperature single crystal X-ray structural studies identify a concerted symmetry-breaking P2(1)/n P2(1)/c as the origin of the rare strong cooperativity and the large hysteresis loop. The analysis of the experimental data discloses two distinct interdependent events, namely, the combination of a gradual ST and an induced crystallographic phase transition, which endows the material with strong bistability and makes it an excellent platform for investigating new generations of ST based electronic and spintronic devices., This work was supported by grant PID2019-106147GB-I00 funded by MCIN/AEI/10.13039/501100011033, Unidad de Excelencia Maria de Maeztu (CEX2019-000919-M); the Generalitat Valenciana through PROMETEO/2016/147 and EU Framework FET-OPEN project COSMICS (grant agreement 766726), by the grant of the Ministry of Education and Science of Ukraine for perspective development of a scientific direction "Mathematical sciences and natural sciences" at Taras Shevchenko National University of Kyiv. We thank Prof. Dr Eric Collet for invaluable comments and suggestions.

[ES] Los sesquicalcogenuros con estequiometria B2X3, con A = Al, Ga e In y X = S, Se y Te, han recibido gran atención a lo largo de los últimos años, en particular en como modificarlos para obtener nuevas estructuras con propiedades inéditas, permitiendo su uso en una amplia variedad de aplicaciones. Si bien vías como el uso de altas/bajas temperaturas o modificar la composición química han sido bastante explotadas para modificar y obtener nuevas estructuras, las altas presiones están ganando auge como una tercera vía para obtener nuevos materiales. El uso de altas presiones implica emplear celdas de yunques de diamantes, preparadas para alcanzar altas presiones, además de altas temperaturas. A estos dispositivos se acoplan multitud de técnicas experimentales, como espectroscópicas (Raman e IR), difracción y absorción de rayos X, medidas de absorción óptica, de resistividad, etc., con el fin de estudiar como la materia evoluciona en dichas condiciones extremas. Adicionalmente, los cálculos teóricos son empleados como apoyo a los resultados experimentales. Dentro de los trabajos existentes a altas presiones de esta familia de compuestos, estos han llegado a conclusiones incluso contradictorias, arrojando más dudas acerca su comportamiento bajo presión. De todos los integrantes de estos sesquicalcogenuros, Ga2S3, In2S3 y In2Se3, han sido los más estudiados bajo presión. En esta tesis se han evaluado los efectos de la alta presión en estos tres sesquicalcogenuros, haciendo uso de espectroscopia Raman y difracción de rayos X, siempre con el soporte de los cálculos teóricos, con el fin de aclarar los resultados publicados anteriormente. Fruto de estos trabajos, la presente tesis recoge los cuatro artículos publicados en revistas indexadas. Dichos artículos han dado luz al comportamiento bajo presión de estos compuestos, como caracterización de propiedades vibracionales y estructurales bajo presión, mecanismos de transición, transiciones de fase inducidas bajo presión, así como caracterizar dichas fases de alta presión. Con todo ello, estos trabajos pretenden no solo conocer fehacientemente el comportamiento bajo presión de estos tres sesquicalcogenuros, sino impulsar futuros trabajos en el resto de los compuestos de esta familia y en otros similares, como en compuestos ternario AB2X4 con estructura tipo espinela y vacantes ordenadas., [CA] Els sesquicalcogenurs amb estequiometria B2X3, amb B = Al, Ga, i In i X = S, Se, i Te, han rebut una gran atenció al llarg dels darrers anys, en particular sobre com modificar-los per tal d'obtindre noves estructures amb propietats inédites, permetent el seu ús en una àmplia varietat d'aplicacions. Si bé l'ùs d'altes/baixes temperatures o modificar la composició química han segut prou explotades per a modificar i obtindre noves estructures, les altes pressions estan guanyant importància com una tercera via per a obtindrer nous materials. L'ús d'altes presions implica emprar cel·les d'encluses de diamants, preparades per a assolir altes presions, a més a més d'altes temperatures. A aquestos dispositius s'acoblen multitud de tècniques experimentals, com ara espectroscòpiques (Raman i IR), difracció i absorció de raigs X, mesures òptiques, de resistivitat, etc, amb la finalitat d'estudiar com la matèria evoluciona en aquestes condicions extremes. Adicionalment, els càlculs teòrics son emprats com a recolçament dels resultats experimentals. Dins dels treballs existents a altes presions a aquesta familia de compostos s'ha arribat a determinades conclusions algunes de les quals son contradictòries, el que ha sembrat moltes dubtes al voltant del seu comportament sota pressió. De tots els integrants d'aquestos sesquicalcogenurs, Ga2S3, In2S3 i In2Se3 han sigut els més estudiats sota pressió. En aquesta tesi doctoral s'han evaluat els efectes de les altes pressions a aquestos tres sesquicalcogenurs, fent ús de l'espectroscopia Raman i la difracció de raigs X, sempre amb el suport dels càlculs teòrics, amb el fi d'aclarir els resultats previament publicats. Fruit d'aquestos treballs, la present tesi doctoral recull els quatre articles publicats a revistes indexades. Aquestos articles han vessat llum sobre el comportament sota pressió d'aquestos compostos, com ara la caracterització de les seues propietats vibracionals i estructurals sota pressió, les transicions de fase induides sota pressió i els mecanismes d'eixes transicions, així com la caracterització de les seues fases d'alta pressió. Amb tot, aquestos treballs pretenen no només conèixer el comportament sota pressió d'aquestos tres sesquicalcogenurs, sino també impulsar futurs treballs a la resta de compostos d'aquesta familia i altres compostos rel·lacionats, com ara els compostos ternaris AB2X4 de tipus espinela i de vacants ordenades., [EN] B2X3 sesquichalcogenides (A = Al, Ga and In, X = S, Se y Te) have received special attention along last years, with great emphasis in tailor them to attain new structures to novel properties, driving them in a huge number of applications. Although high/low temperature or varying chemical composition have been extensively used to modify and obtain new structures, high pressure is gaining relevance as an alternative way to synthetised new materials. To reach such pressures and additionally high/low temperatures, diamond anvil cells are used. Many experimental techniques can be coupled to these tools to study matter under extreme conditions (Raman and IR spectroscopy, X-ray diffraction and absorption, optical absorption, and resistivity measurements, among others). Additionally, computational simulations are used to give further support to the experimental results. Despite the several existing works devoted to the behaviour under pressure of this family, controversial results have been reported. The most studied of these sesquichalcogenides have been Ga2S3, In2S3 and In2Se3. The aim of this thesis is to revisit the pressure effects by means of Raman spectroscopy and X-ray diffraction, with the help of computational simulations, for the purpose of clarify the results published earlier. The current thesis contains the four articles published in indexed journals, resulting from the study of these three sesquichalcogenides. Such articles shed light to the pressure behavior of these compounds, their vibrational and structural properties under pressure, pressure-induced phase transitions and the mechanisms behind them and characterize such high-pressure phases. With these works, we pursue not only a depth understanding of the pressure behavior of these sesquichalcogenides, but boost future high-pressure works on the rest of the family and other similar compounds, as AB2X4 with spinel structure and ordered vacancies., The authors thank the financial support from Spanish Research Agency (AEI) under projects MALTA Consolider Team network (RED2018-102612-T) and projects MAT2015- 710, MAT2016-75586-C4-2/3-P, FIS2017-83295-P, PID2019-106383GB-41/42/43, and PGC2018-097520-A-100, as well as from Generalitat Valenciana under Project PROMETEO/2018/123 (EFIMAT).

[ES] Las perovskitas orgánico-inorgánicas de halogenuros son una familia de materiales estudiados en profundidad por su potencial para construir células solares de alta eficiencia y de bajo coste. Han experimentado un crecimiento exponencial de la eficiencia, pasando del 3% del PCE en 2009 a más del 25% en 2021. Pero todavía quedan retos por superar, como la estabilidad. El objetivo del trabajo es estudiar diferentes tipos de HOIP para aplicaciones fotovoltaicas, incluyendo la optimización del proceso de fabricación y la caracterización completa mediante el análisis de difracción de rayos X, microscopía electrónica de escaneo de emisión de campo, microscopio de fuerza atómica, fotoluminiscencia, UV-absorción visible, cálculo de band-gap, microscopía electrónica de transmitancia, simulación teórica y estudio de degradación de las películas. El objetivo del análisis es obtener la cristalinidad, morfología, topografía, propiedades ópticas, PCE y estabilidad de las capas. Se utilizaron varias estrategias para cumplir el objetivo del trabajo, incluyendo el dopaje con distintos compuestos, la ingeniería de extinción antisolvente y el cambio del catión "B" en la fórmula de las perovskitas; ABX3. La presente disertación se centra en el yoduro de plomo de metilamonio III (CH3NH3I3), que es conocido por presentar una absorción directa de bandgap desde la parte superior de la banda de valencia hasta la parte inferior de la banda de conducción. El bandgap puede modificarse fácilmente variante A, B y X y modularse mediante la selección adecuada de cationes mixtos. Entre las combinaciones posibles, el catión MA y el metal Pb2+ han mostrado excelentes propiedades optoelectrónicas, capas procesables en disolución a baja temperatura y potencial para una estabilidad adecuada, debido a la movilidad del portador de carga muy alta, la gran longitud de difusión de electrones y agujeros, grandes coeficientes de absorción, y bajas tasas de recombinación no radiativa. Concretamente, este doctorado se compone de cuatro artículos: - Stability Improvement of Methylammonium Lead Iodide Perovskite Thin Films by Bismuth Doping - Tetrabutylammonium (TBA)-Doped Methylammonium Lead Iodide: High Quality and Stable Perovskite Thin Films - Manufacture of High-Efficiency and Stable Lead-Free Solar Cells through Antisolvent Quenching Engineering - Investigation on the Stability and Efficiency of MAPbI3 and MASnI3 Thin Films for Solar Cells En resumen, el dopaje de bismuto mejoró la estructura cristalina de la capa absorbente de MAPbI3, mejorando las propiedades optoelectrónicas, la morfología de la superficie de las capas y la estabilidad de los dispositivos. Se estudió el dopaje con bismuto introduciendo cantidades variables de bismuto entre el 1 y el 8% en la solución inicial. Los mejores resultados se obtuvieron con un 2% de bismuto. También se analizó el dopaje con TBA introduciendo diferentes proporciones en la mezcla inicial para la síntesis de capas de MAPbI3. Observamos que un 5% de TBA reduce la densidad de agujeros en las capas y mejora la cristalinidad, mejorando la estabilidad de las capas MAPbI3. Con la proporción óptima de TBA, aumenta el tamaño del grano y la intensidad de la fotoluminiscencia, debido a la disminución de los centros de recombinación. Dado que el plomo es un elemento contaminante, sustituimos a Pb por Sn para obtener capas de MASnI3, lo que provocó un aumento del tamaño del grano y una mejora del coeficiente de absorción de la luz. Sin embargo, el MASnI3 es más inestable que el MAPbI3. Por eso, se utilizaron diferentes antisolventes en la síntesis de MASnI3. Conocida como ingeniería antisolvente, esta técnica estudia varios antisolventes. En este trabajo, el tolueno ha logrado mejorar la estabilidad de las capas de MASnI3. Utilizando un enfoque numérico mediante SCAPS-1D, se calculó que la eficiencia de los dispositivos fotovoltaicos de MASnI3 aumenta un 9,5% en comparación con los dispositivos de MAPbI3., [CAT] Les perovskites orgàniques-inorgàniques d'halogenurs són una família de materials estudiats en profunditat pel seu potencial per construir cèl·lules solars d'alta eficiència i de baix cost. Han experimentat un creixement exponencial de l'eficiència, passant del 3% del PCE el 2009 a més del 25% el 2021. Però encara queden reptes per superar, com l'estabilitat. L'objectiu d'aquest treball és estudiar diferents tipus de HOIP per a aplicacions de cèl·lules solars, incloent l'optimització del procés de fabricació i la caracterització completa mitjançant l'anàlisi de difracció de raigs X, microscòpia electrònica d'escaneig d'emissió de camp, microscopi de força atòmica, fotoluminescència, UV- absorció visible, càlcul de band-gap, microscòpia electrònica de transmitància, simulació teòrica amb SCAPS-1D i estudi de degradació de les pel·lícules. L'objectiu de l'anàlisi és obtenir la cristalinitat, morfologia, topografia, propietats òptiques, PCE i estabilitat de les capes. Es van utilitzar diferents estratègies per complir l'objectiu del treball, incloent el dopatge amb diferents compostos, l'enginyeria d'extinció antisolvent i el canvi del catió "B" en la fórmula general de les perovskites; ABX3. La present dissertació se centra en el iodur de plom de metilamoni III (CH3NH3I3), que és conegut per presentar una absorció directa de bandgap des de la part superior de la banda de valència fins a la part inferior de la banda de conducció. El bandgap es pot modificar fàcilment variant A, B i X i modular-se mitjançant la selecció adequada de cations mixts. Entre les combinacions possibles, el catió MA i el metall Pb2+ han mostrat excel·lents propietats optoelectròniques, capes processables en dissolució a baixa temperatura i potencial per a una estabilitat adequada, a causa de la mobilitat del portador de càrrega molt alta, la gran longitud de difusió d'electrons i forats, grans coeficients d'absorció, i baixes taxes de recombinació no radiativa. Concretament, aquest doctorat es compon de quatre articles: -Stability Improvement of Methylammonium Lead Iodide Perovskite Thin Films by Bismuth Doping -Tetrabutylammonium (TBA)-Doped Methylammonium Lead Iodide: High Quality and Stable Perovskite Thin Films -Manufacture of High-Efficiency and Stable Lead-Free Solar Cells through Antisolvent Quenching Engineering -Investigation on the Stability and Efficiency of MAPbI3 and MASnI3 Thin Films for Solar Cells En resum, el dopatge de bismut ha millorat l'estructura cristal·lina de la capa absorbent de MAPbI3, millorant les propietats optoelectròniques, la morfologia de la superfície de les capes i l'estabilitat dels dispositius. Es va estudiar el dopatge amb bismut introduint quantitats variables de bismut entre l'1 i el 8% en la solució inicial. Els millors resultats es van obtenir amb un 2% de bismut. També es va analitzar el dopatge amb tetrabutilamoni introduint diferents proporcions de TBA a la mescla inicial per a la síntesi de capes de MAPbI3. Observem que afegir un 5% de TBA a la mescla inicial redueix la densitat de forats a les capes i millora la cristal·linitat, millorant en l'estabilitat de les capes MAPbI3. Amb la proporció òptima de TBA, augmenta la mida del gra i la intensitat de la fotoluminescència, a causa de la disminució dels centres de recombinació. Com que el plom és un element contaminant, vam substituir Pb per Sn per obtenir capes de MASnI3, cosa que va provocar un augment de la mida del gra i una millora del coeficient d'absorció de la llum. Tanmateix, el MASnI3 és més inestable que el MAPbI3. Per això, es van utilitzar diferents antisolvents en la síntesi de MASnI3. Coneguda com a enginyeria antisolvent, aquesta tècnica estudia diversos antisolvents. En este treball, el toluè ha aconseguit millorar l'estabilitat de les capes de MASnI3. Utilitzant un enfocament numèric mitjançant SCAPS-1D, hem calculat que l'eficiència dels dispositius fotovoltaics basats en MASnI3 augmenta un 9,5% en comparació amb els dispositius de MAPbI3., [EN] Halide Organic-Inorganic Perovskites are a family of materials that have been studied in depth due to their potential for building high-efficiency and low-cost solar cells. In recent years, they have experienced exponential growth in efficiency, going from 3% of PCE in 2009 to over 25% in 2021. But still, there are numerous challenges to overcome, such as stability. The purpose of this work is to study different kinds of HOIPs for solar cell applications, including the optimization of the manufacturing process and the complete characterization by the analysis of Xray-diffraction, Field Emission Scanning Electron Microscopy, Atomic Force Microscope, photoluminescence, UV-visible absorption, band-gap calculation, Transmittance electron microscopy, theoretical simulation with SCAPS-1D, and degradation study of the films. The objective of the analysis is to obtain crystallinity, morphology, topography, optical properties, PCE, and stability of the layers. Different strategies were used to fulfil the goal of the work, including doping with different compounds, antisolvent quenching engineering, and changing the cation "B" in the general formula of perovskites; ABX3. The present dissertation is focused in methylammonium lead iodide III (CH3NH3I3), which is known for exhibiting direct bandgap absorption from the top of the valence band to the bottom of the conduction band. The bandgap can be easily modified by varying A, B, and X and modulated by the suitable selection of mixed cations. Among the possible combinations, MA cation and metal Pb2+ have exhibited excellent optoelectronic properties, low-temperature solution-processable films, and potential for appropriate stability, due to very high charge-carrier mobility, large electron and hole diffusion length, large absorption coefficients, and low nonradiative recombination rates. Specifically, this PhD is composed of four papers: - Stability Improvement of Methylammonium Lead Iodide Perovskite Thin Films by Bismuth Doping - Tetrabutylammonium (TBA)-Doped Methylammonium Lead Iodide: High Quality and Stable Perovskite Thin Films - Manufacture of High-Efficiency and Stable Lead-Free Solar Cells through Antisolvent Quenching Engineering - Investigation on the Stability and Efficiency of MAPbI3 and MASnI3 Thin Films for Solar Cells To sum up, bismuth doping has improved the crystalline structure of the absorbent layer of MAPbI3, which leads to a significant improvement in the optoelectronic properties, the morphology of the surface of the layers, and even improves the stability of the devices. Bismuth doping was studied introducing variable amounts of bismuth between 1 and 8% in the initial solution. Best results were obtained with 2% bismuth. Doping with tetrabutylammonium (TBA) was also analysed by introducing different proportions of TBA in the initial mixture for the synthesis of MAPbI3 layers. We observed that adding 5% TBA to the initial solution reduces the density of pinholes in the layers and improves crystallinity, which leads to a considerable improvement in the stability of the MAPbI3 layers. With the optimal proportion of TBA, it is possible to increase the grain size and the intensity of the photoluminescence, due to the decrease in recombination centres. Since lead is a polluting element, we substituted Pb for Sn to obtain MASnI3 layers, which led to increasing grain size and enhancing light absorption coefficient. However, MASnI3 shells are more unstable than MAPbI3 shells. To overcome this, different anti-solvents were used in the synthesis of MASnI3 shells. Known as antisolvent engineering, this technique studies several antisolvents. In our work, toluene has managed to improve the stability of the MASnI3 layers. Using a numerical approach using SCAPS-1D, we have calculated that the efficiency of photovoltaic devices (PCE) based on MASnI3 increases by 9.5% when compared to devices based on MAPbI3.

[ES] En la última década, las crecientes necesidades de protección del medio ambiente han estimulado la investigación en el campo de la fotocatálisis. La contaminación del agua por productos químicos orgánicos, tintes textiles y productos farmacéuticos constituye un peligro cada vez más dañino para el medio ambiente, la salud humana y la vida acuática. Para solucionar este problema y luchar contra la contaminación del agua, varios grupos de investigación han demostrado la utilidad del uso de dióxido de titanio TiO2 como un prometedor fotocatalizador no tóxico y de bajo coste para la fotodegradación de contaminantes. Obviamente, como cualquier otro material, el TiO2 tiene limitaciones en varias áreas de aplicación debido a su ancho de banda prohibida, que limita su rango de absorción a los rayos UV. Esto nos incita a asociarlo a semiconductores de banda prohibida baja como PbS. En este trabajo se asociaron nanopartículas de PbS a nanotubos de TiO2 (NTs) para mejorar su actividad fotocatalítica en el visible. Comenzamos nuestro trabajo optimizando la deposición de micro/nanoestructuras de PbS mediante el método hidrotermal mientras estudiamos la influencia de los parámetros de deposición en las propiedades morfológicas y estructurales de las micro/nanoestructuras de PbS de diferentes formas. Inicialmente, la atención se centró en optimizar los parámetros para sintetizar nanopartículas de PbS a partir de microestructuras mediante un simple cambio del precursor aniónico (fuente de S2-). Posteriormente, se realizó un estudio sobre el efecto de la concentración del precursor en la calidad de las nanopartículas de PbS. A continuación, se estudió la influencia de la decoración de las NP de PbS en las propiedades físicas, ópticas y estructurales de las NT de TiO2. Demostramos la efectividad de la técnica SILAR para la realización de heteroestructuras {NPs PbS}n - NTs TiO2, que son adecuadas para la integración en dispositivos fotocatalíticos. Hemos demostrado que la calidad de la estructura cristalina, el tamaño de los cristales y las propiedades ópticas de los sistemas fabricados dependen del número de ciclos SILAR "n" y de la distribución y tamaño de las NP de PbS depositadas por SILAR. Finalmente, se presentó el estudio cinético de la actividad fotocatalítica de NTs de TiO2 puras y decoradas con NPs de PbS para la fotodegradación de antibióticos (tetraciclina) bajo irradiación UV. Primero, encontramos que el sistema PbS NPs/TiO2 NTs es efectivo para la fotodegradación de tetraciclina (TC), con una degradación óptima para un número de ciclo SILAR de deposición de PbS igual a 5. Segundo, estudiamos la actividad fotocatalítica de TiO2 NTs puros en una solución acuosa de TC bajo luz ultravioleta. Después de optimizar las condiciones experimentales, logramos una fotodegradación de aproximadamente el 99% de la tetraciclina después de 5 horas de irradiación. Además, hemos demostrado que el fotocatalizador es estable y podría usarse con éxito durante al menos cinco ciclos sucesivos sin una pérdida significativa de rendimiento. Estos resultados sugieren que el fotocatalizador PbS NPs/TiO2 NTs es un sistema efectivo y prometedor para la purificación de agua. Además, con base en los resultados de las pruebas de atrapamiento, propusimos un mecanismo de fotodegradación que muestra que la capacidad de las NT de TiO2 para oxidar el antibiótico se debe principalmente a los agujeros fotogenerados, así como a los radicales hidroxilo (OH), que se consideran como agentes oxidantes primarios que actúan no solo en la superficie sino también en solución., [CA] A la darrera dècada, les creixents necessitats de protecció del medi ambient han estimulat la recerca en el camp de la fotocatàlisi. La contaminació de l'aigua per productes químics orgànics, tints tèxtils i productes farmacèutics constitueix un perill cada cop més nociu per al medi ambient, la salut humana i la vida aquàtica. Per solucionar aquest problema i lluitar contra la contaminació de l'aigua, diversos grups de recerca han demostrat la utilitat de l'ús de diòxid de titani TiO2 com un prometedor fotocatalitzador no tòxic i de baix cost per a la fotodegradació de contaminants. Òbviament, com qualsevol altre material, el TiO2 té limitacions en diverses àrees d'aplicació a causa de la seva amplada de banda prohibida, que limita el seu rang d'absorció als raigs UV. Això ens incita a associar-ho a semiconductors de banda prohibida baixa com a PbS. En aquest treball es van associar nanopartícules de PbS a nanotubs de TiO2 (NTs) per millorar la seva activitat fotocatalítica en l'espectre visible. Comencem el nostre treball optimitzant la deposició de micro/nanoestructures de PbS mitjançant el mètode hidrotermal mentre estudiem la influència dels paràmetres de deposició en les propietats morfològiques i estructurals de les micro/nanoestructures de PbS de diferents formes. Inicialment, l'atenció es va centrar a optimitzar els paràmetres per sintetitzar nanopartícules de PbS a partir de microestructures mitjançant un simple canvi del precursor aniònic (font de S2-). Posteriorment, es va fer un estudi sobre l'efecte de la concentració del precursor en la qualitat de les nanopartícules de PbS. A continuació, es va estudiar la influència de la decoració de les NP de PbS a les propietats físiques, òptiques i estructurals de les NT de TiO2. Hem demostrat l'efectivitat de la tècnica SILAR per a la realització d'heteroestructures {NPs PbS}n - NTs TiO2, que són adequades per a la integració en dispositius fotocatalítics. Hem demostrat que la qualitat de l'estructura cristal´lina, la mida dels cristals i les propietats òptiques dels sistemes aconseguits depenen del nombre de cicle SILAR "n" i la distribució de mida de les NP de PbS dipositades per SILAR. Finalment, es presenta un estudi cinètic de l'activitat fotocatalítica de NTs de TiO2 pures i decorades amb NPs de PbS per a la fotodegradació d'antibiòtics (tetraciclina) sota irradiació UV. Primer, trobem que el sistema PbS NPs/TiO2 NTs és efectiu per a la fotodegradació de tetraciclina (TC), amb una degradació òptima per a un nombre de cicle SILAR de deposició de PbS igual a 5. Segon, estudiem l'activitat fotocatalítica de TiO2 NTs purs en una solució aquosa de TC sota llum ultraviolada. Després d'optimitzar les condicions experimentals, aconseguim una fotodegradació d'aproximadament el 99% de la tetraciclina després de 5 hores d'irradiació. A més, hem demostrat que el fotocatalitzador és estable i es podria fer servir amb èxit durant almenys cinc cicles successius sense una pèrdua significativa de rendiment. Aquests resultats suggereixen que el fotocatalitzador PbS NPs/TiO2 NT és un sistema efectiu i prometedor per a la purificació d'aigua. A més, amb base en els resultats de les proves de captura, vam proposar un mecanisme de fotodegradació que mostra que la capacitat de les NT de TiO2 per oxidar l'antibiòtic es deu principalment als forats fotogenerats, així com als radicals hidroxil (OH), que es consideren .com a agents oxidants primaris que actuen no només a la superfície sinó també en solució., [EN] The increasing needs for environmental protection have strongly stimulated research in the field of photocatalysis in recent years. Contamination of water by organic chemicals, textile dyes and pharmaceuticals constitute an increasingly harmful hazard to the environment, human health, and aquatic life. To solve this problem and fight water pollution, several research groups have demonstrated the usefulness of using titanium dioxide TiO2 as a promising low-cost non-toxic photocatalyst for the photodegradation of contaminants. Obviously, like any other material, TiO2 has limitations in several areas of application because of its wide band gap, which limits its absorption range to UV. This incites us to associate it to low band gap semicondors such as PbS. In this work, PbS nanoparticles were associated to TiO2 nanotubes (NTs) to improve their photocatalytic activity in the visible. We started our work by optimizing the deposition of PbS micro-nanostructures by the hydrothermal method while studying the influence of deposition parameters on the morphological and structural properties of the different shaped PbS micro-nanostructures. Initially, the focus was on optimizing parameters to synthesize PbS nanoparticles from microstructures by a simple change of the anionic precursor (source of S2-). Subsequently, a study was conducted on the effect of the precursor concentration on the quality of PbS nanoparticles. Next, we also studied the influence of PbS NPs decoration on the physical, optical and structural properties of TiO2 NTs. We demonstrated the effectiveness of the SILAR technique for the realization of {NPs PbS}n - NTs TiO2 heterostructures, which are suitable for integration into photocatalytic devices. We have shown that the quality, crystal structure, crystallite size and optical properties of the achieved systems depend on the SILAR cycle number ''n'' and the size distribution of the SILAR-deposited PbS NPs. Finally, the kinetic study of the photocatalytic activity of pure TiO2 NTs and decorated with PbS NPs for the photodegradation of antibiotics (tetracycline) under UV irradiation was presented. First, we found that the PbS NPs/TiO2 NTs system is effective for the photodegradation of tetracycline (TC), with an optimum degradation for a SILAR cycle number of PbS deposition equal to 5. Second, we studied the photocatalytic activity of pure TiO2 NTs in an aqueous TC solution under UV light. After optimizing the experimental conditions, we achieved a photodegradation of approximately 99% of tetracycline after 5 hours of irradiation. In addition, we have shown that the photocatalyst is stable and could be used successfully for at least five successive cycles without any significant loss of performance. These results suggest that the PbS NPs/TiO2 NTs photocatalyst is an effective and promising system for water purification. In addition, based on the results of the trapping tests, we proposed a photodegradation mechanism that shows that the ability of the TiO2 NTs to oxidize the antibiotic is mainly due to the photogenerated holes as well as the hydroxyl (OH) radicals, which are considered as primary oxidizing agents acting not only on the surface but also in solution.

[ES] La utilización de sistemas de microondas para aplicaciones de calentamiento está muy extendida, principalmente por su uso en el calentamiento doméstico. El volumen de ventas del horno de microondas doméstico refleja un dato curioso: es el electrodoméstico más vendido en el mundo cada año. Por ello, el coste de producción del elemento principal, el magnetrón, presenta unos márgenes de beneficio imbatibles. Sin embargo, los avances en la fabricación de generadores de RF de alta potencia de estado sólido han puesto de manifiesto no solo las limitaciones de los sistemas basados en magnetrón sino también las grandes ventajas de la tecnología de transistores. Actualmente, los amplificadores de potencia de estado sólido han alcanzado una madurez suficiente como para competir en eficiencia, coste y calidad de la onda generada con el magnetrón. Las principales ventajas de los transistores son un reducido tamaño, tensiones de alimentación bajas, un espectro puro en frecuencia, un mayor tiempo de vida y el control digital directo. Los sistemas de microondas con esta tecnología están siendo introducidos en el mercado desde hace diez años, aunque las aplicaciones reales que los utilizan son escasas. La principal razón es la falta de diseños de aplicadores específicos para sacar el máximo provecho a las fuentes de estado sólido. , por tanto, es éste el objetivo de la tesis doctoral. Los sistemas S2MH (Solid-State Microwave Heating) se presentan en esta disertación doctoral como una alternativa que ofrece un calentamiento mejorado. La posibilidad de seleccionar la frecuencia exacta, ajustar la potencia de salida y realizar barridos de fase de forma coherente con múltiples iluminadores proporcionan al sistema un control preciso del proceso de calentamiento. El resultado directo de éste es un calentamiento homogéneo y el uso de la tecnología de microondas en procesos de alto valor añadido y fuerte dependencia con la temperatura. Esta tesis doctoral presenta el trabajo realizado en el diseño y fabricación de dos sistemas S2MH: el primero es un horno estático versátil para diferentes procesos químicos, y el segundo un horno de transporte para el secado de almendras. Estos dos sistemas están formados por el SSMGS (Solid-State Microwave Generator System), que incluye cuatro amplificadores de estado sólido (SSPA) con una generación de la onda coherente, y el aplicador. Para el diseño del SSMGS se han tenido en cuenta los requisitos de potencia y frecuencia de cada aplicación. Se ha utilizado un SSMGS con cuatro PA de 250 W a 2,450 MHz para el horno de aplicaciones químicas, mientras que el secado de almendras necesita cuatro PA de 500 W a 915 MHz. Los dos sistemas de generación de microondas permiten un control individual o combinado de los parámetros de los cuatro módulos amplificadores, i.e., potencia, frecuencia y fase. Todo el proceso de diseño ha sido llevado a cabo mediante modelado multi-físico, poniendo un especial cuidado en las propiedades termofísicas y dieléctricas de los alimentos y soluciones acuosas que tienen una importante dependencia con la temperatura. El comportamiento completo del sistema aplicador se ha estudiado con estas herramientas. Tras la fabricación de los dos prototipos o pruebas de concepto (PoC), los resultados obtenidos presentan un comportamiento similar al modelo y muestran, además, prometedoras mejoras frente a los sistemas actuales. El sistema de aplicaciones químicas presenta mejoras en la distribución de campo, independientemente de la aplicación y la carga. Y el sistema de secado de almendras proporciona un mayor control sobre el proceso evitando la pérdida de material por sobrecalentamiento., [CA] La utilització de sistemes de microones en aplicacions d'escalfament està molt estesa, principalment pel seu us en escalfament domèstic. El volum de ventes del forn de microones domèstic reflexa una informació curiosa: es l'electrodomèstic més venut anualment al món. Per això, el cost de producció del seu element principal, el magnetró, presenta uns marges de benefici imbatibles. No obstant això, els avanços en la fabricació de generadors de RF d'alta potencia d'estat sòlid han posat de manifest tant les limitacions dels sistemes basats en magnetró, com els grans avantatges de la tecnologia de transistors. Actualment, els amplificadors de potència d'estat sòlid son el suficientment madurs com per competir en eficiència, cost i qualitat de l'ona generada amb el magnetró. Els principals avantatges dels transistors son les dimensions reduïdes, tensions d'alimentació baixes, un espectre pur en freqüència, major temps de vida i el control digital directe. Els sistemes de microones amb aquesta tecnologia estan sent introduïts al mercat des de fa deu anys, malgrat les aplicacions reals son escasses. El principal motiu és la falta de dissenys de aplicadors específics per obtindré el màxim profit de les fonts d'estat sòlid. , por tanto, es éste el objetivo de la tesis doctoral. Els sistemes S2MH es presenten en esta dissertació doctoral com una alternativa que ofereix un escalfament millorat. La possibilitat de seleccionar la freqüència exacta, ajustar la potència d'eixida i realitzar un rastreig de fase de forma coherent amb molts il·luminadors proporcionen al sistema un control precís del procés d'escalfament. El resultat directe d'aquest es un escalfament homogeni i el us de la tecnologia de microones en processos d'alt valor afegit i alta sensibilitat a la temperatura. Aquesta dissertació doctoral presenta el treball realitzat en el disseny i fabricació de dos sistemes S2MH: el primer és un forn estàtic i versàtil per a diferent processos químics, i el segon es tracta d'un forn de transport per l'assecatge d'ametles. Tots dos sistemes estan formats pel SSMGS, que inclou quatre amplificadors d'estat sòlid (SSPA) amb generació coherent de l'ona, i l'aplicador. Per al disseny del SSMGS s'han tingut en compte els requisits de potència i freqüència de cada aplicació. S'ha utilitzat un SSMGS amb quatre PA de 250 W a 2,450 MHz per al forn d'aplicacions químiques, mentre que per al d'assecat d'ametla es necessita quatre PA de 500 W a 915 MHz. Ambdós sistemes de generació de microones permeten un control individual o combinat dels paràmetres dels quatre mòduls amplificadors, i.e., potència, freqüència i fase. Tot el procés de disseny ha sigut realitzat amb l'ajuda del modelat multi-físic, prestant una especial atenció a les propietats termofísiques i dielèctriques dels aliments i solucions aquoses, que tenen una important dependència de la temperatura. El comportament complet del sistema aplicador ha sigut estudiat amb estes ferramentes digitals. Després de la fabricació dels dos prototips o proves de concepte (PoC), els resultats obtinguts presenten un comportament similar al model i, a més a més, mostren millores prometedores front als sistemes actuals. El sistema d'aplicacions químiques presenta millores en la distribució de camp, independentment de l'aplicació i la càrrega. I el sistema d'assecatge d'ametlles proporciona un major control sobre el procés, evitant la pèrdua de material per sobreescalfament., [EN] Microwave systems are widely used for heating applications, mainly domestic food heating. The microwave oven sales figures place it as the first domestic appliance, giving its core element, the magnetron, an unbeatable production cost margin. However, recent improvements in RF high-power generator manufacturing have pointed out not only the limitations of these systems based on the magnetron but also the main benefits of the transistors technology. Nowadays, solid-state power amplifiers are mature enough to compete in efficiency, cost and quality with the magnetron. Transistors' main benefits are their reduced size, low operation voltages, pure frequency spectrum, lifetime, and straightforward digital control. Microwave systems based on solid-state power amplifiers have been recently introduced, although the real applications making use of them are rare. The main issue is the lack of applicator designs for specific solid-state sources that fully exploit the mentioned advantages; therefore, this is the main objective of the present PhD thesis. Solid-State Microwave Heating (S2MH) systems are presented in this PhD dissertation as an alternative that offers enhanced heating. Fine frequency selection, adjustable output power and coherent phase sweep in multiple outputs provide the system with accurate control over the heating process. The direct outcome of this control is the production of homogeneous heating and the application of microwave technology into high-added-value temperature-sensitive processes. The complete design and manufacture of two S2MH systems have been carried out and presented in this PhD thesis. The two designed systems are a multi-process chemical lab batch oven and an almond drying conveyorized oven. These two systems are composed of the Solid-State Microwave Generator System (SSMGS), consisting of four Solid-State Power Amplifiers (SSPA) with coherent wave generation, and the applicator. The design of the SSMGS has been carried out according to the power and frequency requirements of the application. A 4 x 250 W SSPA at 2,450 MHz SSMGS has been used for the chemical processes oven, while the almond drying application needs 4 x 500 W SSPA at 915 MHz. Both SSMGS allow the individual or combined digital control of the parameters of the four amplifying modules, i.e., power, frequency and phase. Multiphysics modelling has been thoroughly studied with special attention to the temperature-dependent thermophysical and dielectric properties of food and liquid solutions. The overall applicators' behaviour has been analysed with this tool. After completing the two PoC (Proof of Concept), the results show good agreement with the models. Both PoCs have shown promising improvements to the current state-of-the-art systems. The chemical applications PoC shows electromagnetic field distribution improvements, independent of the application or load. On the other hand, the almonds drying system provides increased control over the process avoiding material losses through overheating.

[EN] We report a method to locally assess the complex shear modulus of a viscoelastic medium. The proposed approach is based on the application of a magnetic force to a millimeter-sized steel sphere embedded in the medium and the subsequent monitoring of its dynamical response. A coil is used to create a magnetic field inducing the displacement of the sphere located inside a gelatin phantom. Then, a phased-array system using 3 MHz ultrasound probe operating in pulse-echo mode is used to track the displacement of the sphere. Experiments were conducted on several samples and repeated as a function of phantom temperature. The dynamic response of the sphere measured experimentally is in good agreement with Kelvin¿Voigt theory. Since the magnetic force is not affected by weak diamagnetic media, our proposal results in an accurate estimation of the force acting on the inclusion. Consequently, the estimated viscoelastic parameters show excellent robustness and the elastic modulus agrees with the measurements using a quasi-static indentation method, obtaining errors below 10% in the whole temperature range. The use of the macroscopic inclusion limits the direct application of this method in a biomedical context, but it provides a robust estimation of the elastic modulus that can be used for material characterization in industrial applications., This work was supported in part by the Spanish Ministry of Science, Innovation and Universities through the "Juan de la Cierva - Incorporacion" under Grant IJC2018-037897-I, in part by the Program "Proyectos I+D+i 2019" under Grant PID2019-111436RB-C22, in part by the Agencia Valenciana de la Innovacio under Grant INNCON/2021/8, in part by Generalitat Valenciana under Grant AICO/2020/268, and in part by the European Union through the Programa Operativo del Fondo Europeo de Desarrollo Regional (FEDER) of the Comunitat Valenciana 20142020 under Grant IDIFEDER/2018/022. The work of Alejandro Cebrecos was supported by the Universitat Politecnica de Valencia under Program PAID-10-19.

[ES] Los Cuidados Paliativos (PC) son cuidados médicos especializados cuyo objetivo esmejorar la calidad de vida de los pacientes con enfermedades graves. Históricamente,se han aplicado a los pacientes en fase terminal, especialmente a los que tienen undiagnóstico oncológico. Sin embargo, los resultados de las investigaciones actualessugieren que la PC afecta positivamente a la calidad de vida de los pacientes condiferentes enfermedades. La tendencia actual sobre la PC es incluir a pacientes nooncológicos con afecciones como la EPOC, la insuficiencia de funciones orgánicas ola demencia. Sin embargo, la identificación de los pacientes con esas necesidades escompleja, por lo que se requieren herramientas alternativas basadas en datos clínicos. La creciente demanda de PC puede beneficiarse de una herramienta de cribadopara identificar a los pacientes con necesidades de PC durante el ingreso hospitalario.Se han propuesto varias herramientas, como la Pregunta Sorpresa (SQ) o la creaciónde diferentes índices y puntuaciones, con distintos grados de éxito. Recientemente,el uso de algoritmos de inteligencia artificial, en concreto de Machine Learning (ML), ha surgido como una solución potencial dada su capacidad de aprendizaje a partirde las Historias Clínicas Electrónicas (EHR) y con la expectativa de proporcionarpredicciones precisas para el ingreso en programas de PC. Esta tesis se centra en la creación de herramientas digitales basadas en ML para la identificación de pacientes con necesidades de cuidados paliativos en el momento del ingreso hospitalario. Hemos utilizado la mortalidad y la fragilidad como los dos criterios clínicos para la toma de decisiones, siendo la corta supervivencia y el aumento de la fragilidad, nuestros objetivos para hacer predicciones. También nos hemos centrado en la implementación de estas herramientas en entornos clínicos y en el estudio de su usabilidad y aceptación en los flujos de trabajo clínicos. Para lograr estos objetivos, en primer lugar, estudiamos y comparamos algoritmos de ML para la supervivencia a un año en pacientes adultos durante el ingreso hospitalario. Para ello, definimos una variable binaria a predecir, equivalente a la SQ y definimos el conjunto de variables predictivas basadas en la literatura. Comparamos modelos basados en Support Vector Machine (SVM), k-Nearest Neighbours (kNN), Random Forest (RF), Gradient Boosting Machine (GBM) y Multilayer Perceptron (MLP), atendiendo a su rendimiento, especialmente al Área bajo la curva ROC (AUC ROC). Además, obtuvimos información sobre la importancia de las variables para los modelos basados en árboles utilizando el criterio GINI. En segundo lugar, estudiamos la medición de la fragilidad de la calidad de vida(QoL) en los candidatos a la intervención en PC. Para este segundo estudio, redujimosla franja de edad de la población a pacientes ancianos (≥ 65 años) como grupo objetivo. A continuación, creamos tres modelos diferentes: 1) la adaptación del modelo demortalidad a un año para pacientes ancianos, 2) un modelo de regresión para estimarel número de días desde el ingreso hasta la muerte para complementar los resultadosdel primer modelo, y finalmente, 3) un modelo predictivo del estado de fragilidad aun año. Estos modelos se compartieron con la comunidad académica a través de unaaplicación web b que permite la entrada de datos y muestra la predicción de los tresmodelos y unos gráficos con la importancia de las variables. En tercer lugar, propusimos una versión del modelo de mortalidad a un año enforma de calculadora online. Esta versión se diseñó para maximizar el acceso de losprofesionales minimizando los requisitos de datos y haciendo que el software respondiera a las plataformas tecnológicas actuales. Así pues, se eliminaron las variablesadministrativas específicas de la fuente de datos y se trabajó en un proceso para minimizar las variables de entrada requeridas, manteniendo al mismo tiempo un ROCAUC elevado del modelo. Como resultado, e, [CA] Les Cures Pal·liatives (PC) són cures mèdiques especialitzades l'objectiu de les qualsés millorar la qualitat de vida dels pacients amb malalties greus. Històricament, s'hanaplicat als pacients en fase terminal, especialment als quals tenen un diagnòstic oncològic. No obstant això, els resultats de les investigacions actuals suggereixen que lesPC afecten positivament a la qualitat de vida dels pacients amb diferents malalties. Latendència actual sobre les PC és incloure a pacients no oncològics amb afeccions comla malaltia pulmonar obstructiva crònica, la insuficiència de funcions orgàniques o lademència. No obstant això, la identificació dels pacients amb aqueixes necessitats éscomplexa, per la qual cosa es requereixen eines alternatives basades en dades clíniques. La creixent demanda de PC pot beneficiar-se d'una eina de garbellat per a identificar als pacients amb necessitats de PC durant l'ingrés hospitalari. S'han proposatdiverses eines, com la Pregunta Sorpresa (SQ) o la creació de diferents índexs i puntuacions, amb diferents graus d'èxit. Recentment, l'ús d'algorismes d'intel·ligènciaartificial, en concret de Machine Learning (ML), ha sorgit com una potencial soluciódonada la seua capacitat d'aprenentatge a partir de les Històries Clíniques Electròniques (EHR) i amb l'expectativa de proporcionar prediccions precises per a l'ingrés enprogrames de PC. Aquesta tesi se centra en la creació d'eines digitals basades en MLper a la identificació de pacients amb necessitats de cures pal·liatives durant l'ingréshospitalari. Hem utilitzat mortalitat i fragilitat com els dos criteris clínics per a lapresa de decisions, sent la curta supervivència i la major fragilitat els nostres objectiusa predir. Després, ens hem centrat en la seua implementació en entorns clínics i hemestudiat la seua usabilitat i acceptació en els fluxos de treball clínics.Aquesta tesi se centra en la creació d'eines digitals basades en ML per a la identificació de pacients amb necessitats de cures pal·liatives en el moment de l'ingrés hospitalari. Hem utilitzat la mortalitat i la fragilitat com els dos criteris clínics per ala presa de decisions, sent la curta supervivència i l'augment de la fragilitat, els nostresobjectius per a fer prediccions. També ens hem centrat en la implementació d'aquesteseines en entorns clínics i en l'estudi de la seua usabilitat i acceptació en els fluxos detreball clínics. Per a aconseguir aquests objectius, en primer lloc, estudiem i comparem algorismesde ML per a la supervivència a un any en pacients adults durant l'ingrés hospitalari.Per a això, definim una variable binària a predir, equivalent a la SQ i definim el conjuntde variables predictives basades en la literatura. Comparem models basats en Support Vector Machine (SVM), k-Nearest Neighbours (kNN), Random Forest (RF), Gradient Boosting Machine (GBM) i Multilayer Perceptron (MLP), atenent el seu rendiment,especialment a l'Àrea sota la corba ROC (AUC ROC). A més, vam obtindre informaciósobre la importància de les variables per als models basats en arbres utilitzant el criteri GINI. En segon lloc, estudiem el mesurament de la fragilitat de la qualitat de vida (QoL)en els candidats a la intervenció en PC. Per a aquest segon estudi, vam reduir lafranja d'edat de la població a pacients ancians (≥ 65 anys) com a grup objectiu. Acontinuació, creem tres models diferents: 1) l'adaptació del model de mortalitat a unany per a pacients ancians, 2) un model de regressió per a estimar el nombre de dies desde l'ingrés fins a la mort per a complementar els resultats del primer model, i finalment,3) un model predictiu de l'estat de fragilitat a un any. Aquests models es van compartiramb la comunitat acadèmica a través d'una aplicació web c que permet l'entrada dedades i mostra la predicció dels tres models i uns gràfics amb la importància de lesvariables. En tercer lloc, vam proposar una versió del model de mortalitat a un any en formade calculadora en línia. Aquesta versió es va di, [EN] Palliative Care (PC) is specialized medical care that aims to improve patients' quality of life with serious illnesses. Historically, it has been applied to terminally ill patients, especially those with oncologic diagnoses. However, current research results suggest that PC positively affects the quality of life of patients with different conditions. The current trend on PC is to include non-oncological patients with conditions such as Chronic Obstructive Pulmonary Disease (COPD), organ function failure or dementia. However, the identification of patients with those needs is complex, and therefore alternative tools based on clinical data are required. The growing demand for PC may benefit from a screening tool to identify patients with PC needs during hospital admission. Several tools, such as the Surprise Question (SQ) or the creation of different indexes and scores, have been proposed with varying degrees of success. Recently, the use of artificial intelligence algorithms, specifically Machine Learning (ML), has arisen as a potential solution given their capacity to learn from the Electronic Health Records (EHRs) and with the expectation to provide accurate predictions for admission to PC programs. This thesis focuses on creating ML-based digital tools for identifying patients with palliative care needs at hospital admission. We have used mortality and frailty as the two clinical criteria for decision-making, being short survival and increased frailty, as our targets to make predictions. We also have focused on implementing these tools in clinical settings and studying their usability and acceptance in clinical workflows. To accomplish these objectives, first, we studied and compared ML algorithms for one-year survival in adult patients during hospital admission. To do so, we defined a binary variable to predict, equivalent to the SQ and defined the set of predictive variables based on literature. We compared models based on Support Vector Machine (SVM), k-Nearest Neighbours (kNN), Random Forest (RF), Gradient Boosting Machine (GBM) and Multilayer Perceptron (MLP), attending to their performance, especially to the Area under the ROC curve (AUC ROC). Additionally, we obtained information on the importance of variables for tree-based models using the GINI criterion. Second, we studied frailty measurement of Quality of Life (QoL) in candidates for PC intervention. For this second study, we narrowed the age of the population to elderly patients (≥ 65 years) as the target group. Then we created three different models: 1) for the adaptation of the one-year mortality model for elderly patients, 2) a regression model to estimate the number of days from admission to death to complement the results of the first model, and finally, 3) a predictive model for frailty status at one year. These models were shared with the academic community through a web application a that allows data input and shows the prediction from the three models and some graphs with the importance of the variables. Third, we proposed a version of the 1-year mortality model in the form of an online calculator. This version was designed to maximize access from professionals by minimizing data requirements and making the software responsive to the current technological platforms. So we eliminated the administrative variables specific to the dataset source and worked on a process to minimize the required input variables while maintaining high the model's AUC ROC. As a result, this model retained most of the predictive power and required only seven bed-side inputs. Finally, we evaluated the Clinical Decision Support System (CDSS) web tool on PC with an actual set of users. This evaluation comprised three domains: evaluation of participant's predictions against the ML baseline, the usability of the graphical interface, and user experience measurement. A first evaluation was performed, followed by a period of implementation of improvements and corrections to the pla

[EN] Due to a continuous abandonment of marginal agricultural land, Mediterranean pine forests are growing both in biomass stock and area but remain mainly unmanaged. Pinus halepensis is one of the main pioneer species with strong expansion throughout the Mediterranean basin. In mature forests and pole stands, selective thinnings aimed to eliminate dominated and dead trees are necessary to improve the resilience and persistence of these forest ecosystems. Bioenergy market provides an opportunity to mobilise this woody material, helping to prevent and reduce wildfires in a context of climate change and energy transition. Despite the existing expertise on wood harvesting, there is a lack of practical knowledge about cost-effective methods for bioenergy use of selective thinnings in such forests. The objective of this study was to compare thinning harvesting methods in representative 63-year-old Pinus halepensis afforestation in pole stage for bioenergy uses, following the silvicultural treatments defined in the Spanish forest management plan. Time studies were performed over six representative plots in Navalon (Spain). Treatments included three plots with the traditional stem wood method combined with the logging of forest residues (integrated system), and three plots with the whole tree chipping (whole tree system). Time, productivity and fuel consumption were recorded for both systems. A woodchip quality assessment of each assortment was performed in the laboratory according to European standards. The results obtained demonstrated that time consumption and productivity were similar between the integrated harvesting system and the whole tree system. Regarding the total energy balance, it should be noted that both systems produce woodchips that contain over ten times more energy than that required to mobilise and process the obtained biomass. Fuel consumption, costs and degree of damage were slightly higher in the whole tree system due to the more intensive forwarding operation. The two assortments of woodchips in the integrated system had a higher (chipped log material) and lower quality (chipped crown material) than whole tree woodchips. In conclusion, integrated harvesting is a better option to diminish fuel consumption, cost and environmental impact, and also to obtain better quality woodchips for the production of added value biofuels (pellets)., VLA and JVOV conceived the study and draft the manuscript; VLA carried out the field measurements; VLA and GSO carried out the biomass tests in the laboratory; VLA, JVOV and JFUS performed the statistical analysis. This work was partially funded by the Government of Valencia (IVACE, Spain) in the framework of the BIOPELLET project. The authors want to acknowledge the support of the forest company Moixent Forestal, the Municipality of Enguera and the AIDIMME Technology Institute and very especially the support of Dr. Raffaele Spinelli for providing methodological support inthe frame of COST Action FP0902. Finally, a special thank to the reviewers who improved and enriched the publication with their valuable contributions.

[ES] Los tumores cerebrales son una de las enfermedades más devastadoras en la actualidad por el importante deterioro cognitivo que sufren los pacientes, la elevada tasa de mortalidad y el mal pronóstico. Los astrocitomas de grado 4 conllevan una supervivencia de cinco años en aproximadamente el 5% de los pacientes diagnosticados, siendo los tumores más agresivos y letales del Sistema Nervioso Central (SNC). Los astrocitomas de grado 4 siguen siendo un problema médico complejo aún sin resolver. A pesar de representar más del 60% de los tumores cerebrales malignos en adultos, estos tumores tienen una baja prevalencia relativa y se consideran una enfermedad huérfana, lo que dificulta el desarrollo de nuevos fármacos o tratamientos que puedan beneficiar a los pacientes. La agresividad de estos tumores se debe a diferentes características, como la fuerte angiogénesis, la necrosis, la microproliferación vascular, la capacidad de invasión e infiltración de las células tumorales y un microambiente inmunológico particular. Además, debido a la rápida progresión de los astrocitomas de grado 4, en la zona de la lesión coexisten diferentes regiones específicas que cambian con el tiempo. Esta naturaleza compleja, junto con la marcada heterogeneidad interpaciente, intratumoral y longitudinal, complica el éxito de un único tratamiento eficaz para todos los pacientes. La imagen de resonancia magnética (MRI) supone una técnica útil para caracterizar la morfología y la vascularidad del tumor. El uso de métodos avanzados y robustos para analizar las imágenes de MR recogidas en las fases iniciales del tratamiento de los pacientes permite la delimitación de las diferentes regiones de los astrocitomas de grado 4, convirtiéndose en herramientas útiles para investigadores, radiólogos y neurocirujanos. Además, el cálculo de biomarcadores vasculares de imagen, como los propuestos en esta tesis, facilitaría la caracterización del tumor, la estimación del pronóstico y los enfoques de tratamiento más personalizados. Esta tesis propone cuatro pilares fundamentales para avanzar en el manejo de los astrocitomas de grado 4. Estos incluyen I) la caracterización multinivel del tumor para mejorar las clasificaciones de los gliomas de alto grado del SNC; II) la búsqueda y desarrollo de biomarcadores robustos para estimar el pronóstico de los pacientes desde el momento prequirúrgico; III) así como para evaluar la respuesta a los tratamientos y la selección de los pacientes que pueden beneficiarse de terapias específicas; y IV) el diseño e implementación de estudios clínicos y protocolos para la recogida de datos a largo plazo de cohortes de pacientes notables a nivel internacional. Para abordar estos cuatro pilares, se ha utilizado un enfoque interdisciplinario que combina el análisis de imágenes médicas, técnicas avanzadas de inteligencia artificial y variables moleculares, histopatológicas y clínicas. En conclusión, hemos abordado la influencia de la heterogeneidad interpaciente e intratumoral del astrocitoma de grado 4 para la caracterización y clasificación del tumor, la estimación del pronóstico del paciente y la predicción de las respuestas al tratamiento. Además, se han diseñado e implementado diferentes estudios clínicos que permiten la recogida de datos multinivel de cohortes internacionales de pacientes con astrocitoma de grado 4., [CA] Els tumors cerebrals són una de les malalties més devastadores en l'actualitat per la important deterioració cognitiva que pateixen els pacients, l'elevada taxa de mortalitat i el mal pronòstic. Els astrocitomes de grau 4 comporten una supervivència de cinc anys en aproximadament el 5% dels pacients diagnosticats, sent els tumors més agressius i letals del Sistema Nerviós Central (SNC). Els astrocitomes de grau 4 continuen sent un problema mèdic complex encara sense resoldre. Malgrat representar més del 60% dels tumors cerebrals malignes en adults, aquests tumors tenen una baixa prevalença relativa i es consideren una malaltia òrfena, la qual cosa dificulta el desenvolupament de nous fàrmacs o tractaments que puguen beneficiar als pacients. L'agressivitat d'aquests tumors es deu a diferents característiques, com la forta angiogènesis, la necrosi, la microproliferació vascular, la capacitat d'invasió i infiltració de les cèl·lules tumorals i un microambient immunològic particular. A més, a causa de la ràpida progressió dels astrocitomes de grau 4, en la zona de la lesió coexisteixen diferents regions específiques que canvien amb el temps. Aquesta naturalesa complexa, juntament amb la marcada heterogeneïtat interpacient, intratumoral i longitudinal fa que es complique l'èxit d'un únic tractament eficaç per a tots els pacients. L'imatge de ressonància magnètica (MRI) suposa una tècnica útil per a caracteritzar la morfologia i la vascularitat del tumor. L'ús de mètodes avançats i robustos per a analitzar les imatges de MR recollides en les fases inicials del tractament dels pacients permet la delimitació de les diferents regions dels astrocitomes de grau 4, convertint-se en eines útils per a investigadors, radiòlegs i neurocirugians. A més, el càlcul de biomarcadors vasculars d'imatge, com els proposats en aquesta tesi, facilitaria la caracterització del tumor, l'estimació del pronòstic i els enfocaments de tractament més personalitzats. Aquesta tesi proposa quatre pilars fonamentals per a avançar en el maneig dels astrocitomes de grau 4. Aquests inclouen I) la caracterització multinivell del tumor per a millorar les classificacions dels gliomes d'alt grau del SNC; II) la cerca i desenvolupament de biomarcadors robustos per a estimar el pronòstic dels pacients des del moment prequirúrgic; III) així com per a avaluar la resposta als tractaments i la selecció dels pacients que poden beneficiar-se de teràpies específiques; i IV) el disseny i implementació d'estudis clínics i protocols per a la recollida de dades a llarg termini de cohorts de pacients notables a nivell internacional. Per a abordar aquests quatre pilars, s'ha utilitzat un enfocament interdisciplinari que combina l'anàlisi d'imatges mèdiques, tècniques avançades d'intel·ligència artificial i variables moleculars, histopatològiques i clíniques. En conclusió, hem abordat la influència de l'heterogeneïtat interpacient i intratumoral del astrocitoma de grau 4 per a la caracterització i classificació del tumor, l'estimació del pronòstic del pacient i la predicció de les respostes al tractament. A més, s'han dissenyat i implementat diferents estudis clínics que permeten la recollida de dades multinivell de cohorts internacionals de pacients amb astrocitoma de grau 4., [EN] Brain tumors are one of the most devastating diseases today because of the significant cognitive impairment suffered by patients, high mortality rates, and poor prognosis. Astrocytomas grade 4 bring five-year survival in approximately 5% of diagnosed patients, being the most aggressive and lethal tumors of the Central Nervous System (CNS). Astrocytomas grade 4 continue to be an unresolved complex medical problem. Despite accounting for more than 60% of malignant brain tumors in adults, these tumors have a low relative prevalence and are considered an orphan disease, making difficult developing new drugs or treatments that might benefit patients. The aggressiveness of these tumors is due to different characteristics, such as strong angiogenesis, necrosis, vascular microproliferation, the capacity of the tumor cells to invade and infiltrate, and a particular immune microenvironment. In addition, due to the rapid progression of astrocytomas grade 4, different specific regions coexist in the lesion area which change over time. This complex nature, along with the marked interpatient, intratumor, and longitudinal heterogeneity, makes complicate the success of a single efficient treatment for all patients. Magnetic Resonance Imaging (MRI) represents a useful technique to characterize tumor morphology and vascularity. Using advanced and robust methods to analyze MR images collected from initial stages of patient management allows the delineation of different regions of astrocytomas grade 4, becoming useful tools for researchers, radiologists and neurosurgeons. In addition, the calculation of imaging vascular biomarkers, such as those proposed in this thesis, would facilitate tumor characterization, prognosis estimation and more personalized treatment approaches. This thesis proposes four fundamental pillars to advance the management of astrocytomas grade 4. These include I) the multilevel characterization of the tumor to improve classifications of high-grade CNS gliomas; II) the search and development of robust biomarkers for estimating patient prognosis from the presurgical moment; III) as well as for evaluating the response to treatments and the selection of patients who may benefit from specific therapies; and IV) the design and implementation of clinical studies and protocols for long-term collecting data from internationally remarkable cohorts of patients. To address these four pillars, an interdisciplinary approach has been used that combines medical imaging analysis, advanced artificial intelligence techniques, and molecular, histopathological, and clinical variables. Concluding, we have addressed the influence of both interpatient and intratumor heterogeneity of astrocytoma grade 4 for tumor characterization and classification, patient prognosis estimation and predicting treatment responses. In addition, different clinical studies have been designed and implemented allowing the collection of multilevel data from international cohorts of patients with astrocytoma grade 4.

[EN] Information theory and Thermodynamics have developed closer in the last years, with a growing application palette in which the formal equivalence between the Shannon and Gibbs entropies is exploited. The main barrier to connect both disciplines is the fact that information does not imply a dynamics, whereas thermodynamic systems unfold with time, often away from equilibrium. Here, we analyze chain-like systems comprising linear sequences of physical objects carrying symbolic meaning. We show that, after defining a reading direction, both reversible and irreversible informations emerge naturally from the principle of microscopic reversibility in the evolution of the chains driven by a protocol. We find fluctuation equalities that relate entropy, the relevant concept in communication, and energy, the thermodynamically significant quantity, examined along sequences whose content evolves under writing and revision protocols. Our results are applicable to nanoscale chains, where information transfer is subject to thermal noise, and extendable to virtually any communication system., This work was supported by Ministerio de Ciencia e Innovacion, Grant Number PID2019-107391RB-I00.

A low-toxicity photopolymer was employed to prepare holographic solar concentrators (HSCs). The main aim of this study is to obtain a versatile holographic element to concentrate the sunlight from different relative positions of the Sun during the day, avoiding the need of expensive tracking systems. Multiplexed holographic elements that combine symmetric and asymmetric holographic lenses of low frequency (545 l/mm) have been recorded in the same plate to concentrate the sunlight from sunrise to sunset. The holographic behavior of HSCs has been studied by measuring the angular diffraction efficiency at 633 nm (close to the maximum response of silicon cells). The efficiency of the complete system “HSC-solar cell” has been evaluated by measuring the short-circuit current (Isc) under solar illumination at different incident angles. This study overcomes the trade-off between good efficiency and high incident acceptance angle, showing an important breakthrough to obtain wide acceptance angle systems. Universidad de Alicante (UAFPU20-23); Generalitat Valenciana (CDEIGENT/2018/024, IDIFEDER/2021/014, PROMETEO/2021/006); Ministerio de Ciencia e Innovación (PID2019-106601RB-I00).

[EN] High-pressure synchrotron X-ray diffraction studies of cobalt iodate, Co(IO3)(2), reveal a counterintuitive pressure-induced expansion along certain crystallographic directions. High-pressure Raman and infrared spectroscopy, combined with density-functional theory calculations, reveal that with increasing pressure, it becomes energetically favorable for certain I-O bonds to increase in length over the full range of pressure studied up to 28 GPa. This phenomenon is driven by the high-pressure behavior of iodate ion lone electron pairs. Two pressure-induced isosymmetric monoclinic-monoclinic phase transitions are observed at around 3.0 and 9.0 GPa, which are characterized by increasing oxygen coordination of the iodine atoms and the probable formation of pressure-induced metavalent bonds. Pressure-volume equations of state are presented, as well as a detailed discussion of the pressure dependences of the observed Raman- and infrared-active modes, which clarifies previous inconsistencies in the literature., This work was supported by the Generalitat Valenciana under Project PROMETEO 2018/123-EFIMAT and by the Spanish Ministerio de Ciencia, Universidades, e Investigacion under Projects PID2019-106383GB-41/42/43, as well as through MALTA Consolider Team research network (RED2018102612-T). A.M. and P.R.-H. acknowledge computing time provided by Red Espan~ola de Supercomputacion (RES) and the MALTA Consolider Team cluster. D.E. acknowledges the resources and technical assistance provided by the Informatics Service of Universitat de Valencia through the Tirant III cluster. A.L. and D.E. would like to thank the Generalitat Valenciana for the Ph.D. Fellowship no. GRISOLIAP/2019/025. R.T. acknowledges funding from the Spanish Ministerio de Economia y Competitividad (MINECO) via the Juan de la Cierva Formacion fellowship (FJC2018-036185-I). C.P. is thankful for the financial support of the Spanish Mineco Project no. FIS2017-83295-P. E.B would like to thank the University of Valencia for his "Attraccio de Talent" postdoctoral contract (UV-INV_POSTDOC19-1026935). The authors thank Sandrine Beauquis from Symme, Universite Savoie Mont Blanc (France), for her technical assistance concerning the SEM and ADX analyses. PXRD experiments were performed at the MSPD beamline of ALBA Synchrotron (experiment no. 2019083663). IR experiments were performed at the MIRAS beamline of ALBA Synchrotron (experiment no. 2020024118).

[EN] The electroactive characteristics of poly(vinylidene fluoride) (PVDF) are widely and increasingly being used in technological applications, where controlling the crystallization of the PVDF is of utmost importance. The nucleation and growth of crystals in the beta or. electroactive phases, or in the nonelectroactive a phase, depends on a number of factors that, despite the studies carried out, are still to be properly understood, in particular, when blended with specific active fillers. In this context, the crystallization of PVDF blended with the ionic liquid (IL) 1-ethyl-3-methylimidazolium hexafluorophosphate ([Emim][PF6]) has been analyzed. Both components are capable of crystallizing from the melt. The growth of the crystalline phases of PVDF during isothermal crystallization at different temperatures has been monitored using Fourier transform infrared (FTIR) spectroscopy. The isothermal crystallization kinetics of PVDF and the melting temperatures of both PVDF and IL were characterized by differential scanning calorimetry, and the microstructures of the blends were analyzed by optical and electron microscopy. It is observed for [Emim][PF6]/PVDF blends that the isothermal crystallization from the melt between 120 and 162 degrees C produces PVDF crystallites in the beta and. electroactive phases, while the formation of a-phase crystals is nearly suppressed. The morphology of the blends is altered by the addition of IL, which results in the separation of solid phases at room temperature. In addition, [Emim][PF6] remains liquid when mixed with the amorphous PVDF chains due to the cryoscopic descent., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019. The authors thank FEDER funds through the COMPETE 2020 Program and National Funds through FCT under the projects PTDC/BTM-MAT/28237/2017, PTDC/EEI-SII/5582/2014, and PTDC/FIS-MAC/28157/2017. D.M.C. thank the FCT for grant SFRH/BPD/121526/2016 and C.M.C. for the Investigator FCT Contract 2020.04028.CEECIND. The work of the Spanish groups has been funded by the Spanish State Research Agency (AEI) through the PID2019-106099RB-C41/AEI/10.13039/501100011033 project and from the Basque Government Industry and Education Departments under the ELKARTEK and PIBA (PIBA-2018-06) programs, respectively. CIBER-BBN is an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER Actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund.

[EN] In the current work, an energy-efficient solution combustion route is adopted to synthesize silver-modified ZnO nanomaterials having 1, 3, 5, and 7 mol% of silver content. The samples were characterized by different techniques to uncover the morphology, crystallinity, chemical state, and optical properties. The thermally stable, well-crystalline wurtzite phase of ZnO and cubic phase of silver was obtained in the synthesized samples. It was found that due to the surface plasmon resonance effect of silver there is an enhancement in the light absorption after the introduction of Ag in ZnO. Photocatalytic performances of all samples are analyzed by taking Cibacron Red and Triclopyr as model pollutants. It is observed that due to the surface plasmon resonance effect and formation of oxygen vacancies, Ag¿ZnO nanomaterials containing 7 mol% silver content showed the highest activity for both pollutants under UV illumination. The photoluminescence technique is used to detect the recombination of photoinduced charged species. The samples showed superior activity in the neutral medium as compared to the acidic and basic medium. The synthesized materials are highly beneficial for the energy-efficient removal of pollutants from the environment., Maharshi Dayanand University, Rohtak and University Grant Commission are acknowledged by NK and SY for financial assistance in form of Radha Krishnan Minor Project and Senior Research Fellowship respectively.

[EN] Neural progenitor cells (NPCs) have been shown to serve as an efficient therapeutic strategy in different cell therapy approaches, including spinal cord injury treatment. Despite the reported beneficial effects of NPC transplantation, the low survival and differentiation rates constrain important limitations. Herein, a new methodology has been developed to overcome both limitations by applying a combination of wireless electrical and magnetic stimulation to NPCs seeded on aligned poly(lactic acid) nanofibrous scaffolds for in vitro cell conditioning prior transplantation. Two stimulation patterns were tested and compared, continuous (long stimulus applied once a day) and intermittent (short stimulus applied three times a day). The results show that applied continuous stimulation promotes NPC proliferation and preferential differentiation into oligodendrocytic and neuronal lineages. A neural-like phenotypic induction was observed when compared to unstimulated NPCs. In contrast, intermittent stimulation patterns did not affect NPC proliferation and differentiation to oligodendrocytes or astrocytes morphology with a detrimental effect on neuronal differentiation. This study provides a new approach of using a combination of electric and magnetic stimulation to induce proliferation and further neuronal differentiation, which would improve therapy outcomes in disorders such as spinal cord injury., Grants RTI2018-095872-B-C21/ERDF and RTI2018-095872-B-C22/ERDF funded by MCIN/AEI//10.13039/501100011033 and by ERDF A way of making Europe. This project was also funded by Project 964562 H2020 FetOpen program. Irene Cuenca Ortola acknowledges the grant PRE2019-090716 funded by MCIN/AEI/10.13039/501100011033 and by ESF Investing in your future. B. Martinez Rojas was supported by a grant from the Conselleria de Educacion, Investigacion, Cultura y Deporte de la Generalitat Valenciana and the European Social Fundation ACIF/2019/120.

[EN] Sustainable Development Goals (SDGs) currently represent a challenge for the future and are already being implemented in different working areas. That is why, from the moment a student starts university education, professors must take the lead to include them in the different subjects offered in the curricula of the different Degrees. Physics is a subject that represents a fundamental basis in many engineering degrees studies. On the one hand, the importance of this subject for the future of students is well known. However, this fundamental nature means that it is perceived by the students as a subject with no connection with the degree they aspire to achieve. Additionally, the heterogeneous level of training of the students, especially in the first courses, is a limitation. This makes it difficult to relate the content of the subject with the everyday phenomena and favours the lack of interest in them. One way to motivate students and use the active and constructive teaching methodology is to introduce SDGs within the subject, given the high sensitivity of current generations on Planet Earth. The introduction of these new training tools is not easy because the teaching of the fundamental bases requires most of the available time. This work aims to bring Physics closer to society through SDGs. For this purpose, a challenge is incorporated into the subject¿s curriculum for each thematic block that students must overcome. In this way, two important training actions are combined, efficient teaching is carried out, and the students become aware of SDGs, which are necessary for their future work. PoliformaT, the e-learning platform implemented in the Universitat Politècnica de València, facilitates the use of these new teaching methodologies that combine traditional on-site laboratory tasks with other learning assignments carried out autonomously online by students., The authors would like to thank the educational innovation group Multidisciplinary Teaching Innovation Methodology (Teach- Inn) (GIE-64) from Universidad de Las Palmas de Gran Canaria.

[EN] Nowadays, the search for new active and constructive learning methodologies is one of the pedagogical objectives in universities and other educational institutions. In the degrees taught at the Escola Tècnica Superior d'Enginyeria Agronòmica i del Medi Natural (ETSEAMN), the phenomena associated with heat transport and the underlying physics are studied. In the master classes, within the framework of food science and technology subjects, the phenomenon of this energy balance in a one-dimensional system is explained. In the present work, the analytical solution is developed and evaluated, and a numerical model achieving the same solution is shown. One of the advantages of using numerical tools is that more complex solutions can be obtained, even if the corresponding analytical solution does not exist or is not known, which is useful for engineering students. In this work, it is shown that changing the boundary conditions, geometry, or dimension in the system and the mathematical model, and solving it by applying a numerical solution method is easier and more comprehensive for students rather than facing the complexity of the analytical solutions. To demonstrate the applications and possibilities of this approach, a simple way of modifying the degrees of freedom of the same problem applied in the case of a vegetable subjected to a heat treatment is shown. Thus, the students can understand how these modifications affect the solution and comprehend that the dimension of some problems can be simplified in order to contextualize them. The development of PoliformaT, the e-learning platform implemented in the Universitat Politècnica de València facilitates the use of these new teaching models that combine traditional on-site laboratory tasks assignments with other learning assignments carried out autonomously online by students., The authors would like to thank the educational innovation group Multidisciplinary Teaching Innovation Methodology (Teach- Inn) (GIE-64) from Universidad de Las Palmas de Gran Canaria. In addition, we greatly appreciate José Bon Corbín his invaluable support and time.

The holographic principle, discovered by Gabor, and realized by Leith & Upatnieks and Denisyuk is discussed. The intrinsic value of this idea and its continuing ability to motivate and inspire engineers and applied physicists is reviewed. Science Foundation Ireland, The Irish Research Council for Science Engineering and Technology, Enterprise Ireland, and the European Commission. “Generalitat Valenciana” of Spain (projects PROMETEO/2021/006 and IDIFEDER/2021/014, cofunded by European Union through the FEDER Programme) and by the “Ministerio de Ciencia e Innovación” of Spain (projects FIS2017-82919-R and PID2019-106601RB-I00).

Perylenediimide (PDI) compounds with no substituents in their core are widely used as the active units of thin-film organic lasers. Recently, bay-substituted PDIs (b-PDIs) bearing two sterically hindering diphenylphenoxy groups at the 1,7-bay positions have received great attention because they show red-shifted emission with respect to bay-unsubstituted PDIs, while maintaining high photoluminescence (PL) quantum yields and low amplified spontaneous emission (ASE) thresholds even at high doping rates. However, their ASE photostability is relatively low compared to that of state-of-the-art PDIs. Thus, the design of b-PDIs with improved ASE photostability remains a challenge. Here, the synthesis of two b-PDIs with phenyl-type substituents at the imide positions is reported. Complete characterization of their optical properties, including absorption, PL, ASE, and transient spectroscopy, supported also by quantum chemical calculations, is performed with the dyes diluted in either a liquid solvent or a polystyrene film. Film experiments were accomplished at very low doping rates, to resemble the isolated molecule behavior, and also in a range of increasing doping rates, to investigate concentration quenching effects. The reported b-PDIs show improved ASE photostability (3-fold) with respect to b-PDIs with aliphatic-type substituents at the imide positions, whilst they show more propensity toward aggregation. The authors thank the Spanish Ministry of Economy and Competitiveness MINECO and the European Social Funds (project MAT2015-66586-R and FPI fellowship BES-2016-077681), the Ministry of Science and Innovation (MICINN) and the European FEDER funds (CTQ2016-77039-R, PGC2018-099568-B-I00, and PID2019-109200GB-I00, and Unidad de Excelencia María de Maeztu CEX2019-000919-M), and the Generalitat Valenciana (PROMETEO/2020/077 and SEJI/2018/035). J.A. acknowledges the MICINN for the “Ramón-y-Cajal” Fellowship (RyC-2017-23500).

[Otros] Dans cette revue, nous présentons des résultats sur l'absorption acoustique parfaite sub-longueur d'onde faisant appel à des métamatériaux acoustiques avec des résonateurs Helmholtz pour différentes configurations. L'absorption parfaite à basse fréquence nécessite une augmentation du nombre d'états aux basses fréquences ainsi que de trouver les bonnes conditions pour une adaptation d'impédance avec le milieu environnant. Si en outre, on souhaite réduire les dimensions géométriques des structures proposées pour des questions pratiques, on peut utiliser des résonateurs locaux judicieusement conçus afin d'attendre une absorption parfaite sub-longueur d'onde. Les résonateurs de Helmholtz se sont révélés de bons candidats en raison de leur accordabilité aisée de la géométrie, donc de la fréquence de résonance, de la fuite d'énergie et des pertes intrinsèques. Lorsqu'ils sont branchés à un guide d'ondes ou à un milieu environnant, ils se comportent comme des systèmes ouverts, avec pertes et résonances caractérisés par leur fuite d'énergie et leurs pertes intrinsèques. L'équilibre entre ces deux aspects représente la condition de couplage critique et donne lieu à un maximum d'absorption d'énergie. Le mécanisme de couplage critique est ici représenté dans le plan de fréquence complexe afin d'interpréter la condition d'adaptation d'impédance. Dans cette revue, nous discutons en détail la possibilité d'obtenir une absorption parfaite par ces conditions de couplage critiques dans différents systèmes tels que la réflexion (à un port), la transmission (à deux ports) ou les systèmes à trois ports., [EN] In this review, we present the results on sub-wavelength perfect acoustic absorption using acoustic metamaterials made of Helmholtz resonators with different setups. Low frequency perfect absorption requires to increase the number of states at low frequencies and finding the good conditions for impedance matching with the background medium. If, in addition, one wishes to reduce the geometric dimensions of the proposed structures for practical issues, one can use properly designed local resonators and achieve subwavelength perfect absorption. Helmholtz resonators have been shown good candidates due to their easy tunability of the geometry, so of the resonance frequency, the energy leakage and the intrinsic losses. When plugged to a waveguide or a surrounding medium they behave as open, lossy and resonant systems characterized by their energy leakage and intrinsic losses. The balance between these two represents the critical coupling condition and gives rise to maximum energy absorption. The critical coupling mechanism is represented here in the complex frequency plane in order to interpret the impedance matching condition. In this review we discuss in detail the possibility to obtain perfect absorption by these critical coupling conditions in different systems such as reflection (one-port), transmission (two-ports) or three-ports systems., The authors gratefully acknowledge the ANR-RGC METARoom (ANR-18-CE08-0021) project and the project HYPERMETA funded under the program Étoiles Montantes of the Région Pays de la Loire. NJ acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities (MICINN) through grant ¿Juan de la Cierva-Incorporación¿ (IJC2018-037897- I). This article is based upon work from COST Action DENORMS CA15125, supported by COST (European Cooperation in Science and Technology).

[EN] Mesenchymal stem cells represent an important resource, for bone regenerative medicine and therapeutic applications. This review focuses on new advancements and biophysical tools which exploit different physical and chemical markers of mesenchymal stem cell populations, to finely characterize phenotype changes along their osteogenic differentiation process. Special attention is paid to recently developed label-free methods, which allow monitoring cell populations with minimal invasiveness. Among them, quantitative phase imaging, suitable for single-cell morphometric analysis, and nanoindentation, functional to cellular biomechanics investigation. Moreover, the pool of ion channels expressed in cells during differentiation is discussed, with particular interest for calcium homoeostasis.Altogether, a biophysical perspective of osteogenesis is proposed, offering a valuable tool for the assessment of the cell stage, but also suggesting potential physiological links between apparently independent phenomena.

Electronic excitations and ionisations produced by electron impact are key processes in the radiation-induced damage mechanisms in materials of biological relevance, underlying important medical and technological applications, including radiotherapy, radiation protection in manned space missions and nanodevice fabrication techniques. However, experimentally measuring all the necessary electronic interaction cross-sections for every relevant material is an arduous task, so it is necessary having predictive models, sufficiently accurate yet easily implementable. In this work we present a model, based on the dielectric formalism, to provide reliable ionisation and excitation cross-sections for electron-impact on complex biomolecular media, taking into account their condensed-phase nature. We account for the indistinguishability and exchange between the primary beam and excited electrons, for the molecular electronic structure effects in the electron binding, as well as for higher-order corrections to the first Born approximation. The resulting approach yields total ionisation cross-sections, energy distributions of secondary electrons, and total electronic excitation cross-sections for condensed-phase biomaterials, once the electronic excitation spectrum is known, either from experiments or from a predictive model. The results of this methodology are compared with the available experimental data in water and DNA/RNA molecular building blocks, showing a very good agreement and a great predictive power in a wide range of electron incident energies, from the large values characteristic of electron beams down to excitation threshold. The proposed model constitutes a very useful procedure for computing the electronic interaction cross-sections for arbitrary biological materials in a wide range of electron incident energies., 18 pages, 10 figures

[EN] In this study, we demonstrate that the crystallization process of CsPbI2Br films can be modulated when small amounts of additives are added to the precursor solution, leading to the formation of the bright brownish a-phase perovskite films with high orientation along the [100] crystallographic direction. Doped CsPbI2Br films exhibit improved crystallinity, with high coverage, large grain size and pinhole-free surface morphology, suitable for making high performance optoelectronic devices. We also explored the role of Cl in the photophysical properties of CsPbI2Br perovskite films using the temperature dependent photoluminescence technique. We found that the Cl ions enhance the photoluminescence emission by reducing the density of trap states, and also decrease the exciton binding energy from (22.3) meV to (11.2) meV. We believe this work contributes to understanding the effect of doping on the crystallization process with an in-depth insight into the photophysical properties of the cesium-based perovskite materials.

The structural, vibrational and electronic properties of the compressed beta-Sb2O3 polymorph, a.k.a. mineral valentinite, have been investigated in a joint experimental and theoretical study up to 23 GPa. The compressibility of the lattice parameters, unit-cell volume and polyhedral unit volume as well as the behaviour of its Raman- and IR-active modes under compression have been interpreted on the basis of ab initio theoretical simulations. Valentinite shows an unusual compressibility up to 15 GPa with four different pressure ranges, whose critical pressures are 2, 4, and 10 GPa. The pressure dependence of the main structural units, the lack of soft phonons, and the electronic density charge topology address the changes at those critical pressures to isostructural phase transitions of degree higher than 2. In particular, the transitions at 2 and 4 GPa can be ascribed to the changes in the interaction between the stereochemically-active lone electron pairs of Sb atoms under compression. The changes observed above 10 GPa, characterized by a general softening of several Raman- and IR-active modes, point to a structural instability prior to the 1st-order transition occurring above 15 GPa. Above this pressure, a tentative new high-pressure phase (s.g. Pcc2) has been assigned by single-crystal and powder X-ray diffraction measurements., This research was partially supported by the MINECO (FIS2017-83295-P, MAT2016-75586-C4-1/2/3-P, PGC2018- 097520-A-100, RED and PID2019-106383GB-41/42/43), by the MALTA-CONSOLIDER TEAM network (RED2018-102612-T) and by the EU-FEDER. JAS acknowledges the Ramon y Cajal fellowship (RYC-2015-17482) for financial support. VM thanks the Juan de la Cierva Program (FJCI-2016-27291) and Beatriz Galindo Fellowship (BG20/00077) for financial support. We also thank the ALBA (2016091901 experiment) and DIAMOND light source (CY22223 experiment) for providing beamtime, and Mark Warren, Sarah Barnett and Dominik Daisenberger for their help in the single-crystal X-ray diffraction experiment under pressure.

The year 2022 marks the 75th anniversary of Dennis Gabor’s invention of the holographic method, what he called “microscopy by reconstructed wave-fronts”, as well as the 60th anniversary of the publication in 1962 of two seminal papers in the field of holography: the introduction of the reflection hologram by Yuri Denisyuk, and the description of the holographic process from the point of view of communication theory by Emmett Leith and Juris Upatnieks. Within the framework of these celebrations, a historical review of the origins of holography is presented with special emphasis on the contributions of Gabor, Denisyuk and Leith to the development of holography. This work was supported by the by “Generalitat Valenciana” of Spain (projects PROMETEO/2021/006 and IDIFEDER/2021/014, cofunded by European Union through the FEDER Programme) and by the “Ministerio de Ciencia e Innovación” of Spain (projects FIS2017-82919-R and PID2019-106601RB-I00).

Here we report on the identification and characterization of suspended double-stranded Au atomic chains up to ∼4 atoms long, using a scanning tunneling microscope adapted for the fabrication and simultaneous recording of the conductance. These chains are one of the smallest structures with the highest stability connecting two metallic electrodes, identified from the evolution of the conductance in the process of the controlled breakage of the contact between two metals. Molecular dynamics simulations and density functional theory electron transport calculations help us to unveil the richness of the geometric structures appearing in the experiments in the form of double-stranded chains, their stability, and how these can evolve into the formation of monoatomic chains. This work was supported by the Generalitat Valenciana through PROMETEO2017/139, the Spanish government through Grants MAT2016-78625-C2-1-P, FIS2016-80434-P, and PID2019-109539GB-C4, and the Marı́a de Maeztu Programme for Units of Excellence in R&D (CEX2018-000805-M); by Comunidad Autónoma de Madrid through Grant S2018/NMT-4321 (NanomagCOST-CM), by the Fundación Ramón Areces, and by the European Union Graphene Flagship under Grant No. 604391. C.S. gratefully acknowledges financial support from Generalitat Valenciana with the programs GENT (CDEIGENT2018/028). J.J.P. acknowledges the computer resources and assistance provided by the Barcelona Supercomputing Center (FI-2019-2-0007) and the Universidad Autónoma de Madrid.

[EN] We report high-pressure Raman spectroscopy studies of Fe(IO3)(3) up to nearly 21 GPa that have been interpreted with the help of density functional theory calculations, which include the calculation of phonon dispersion curves and elastic constants at different pressures. Zero-pressure Raman-active mode frequencies and their pressure dependences have been determined. Modes have been assigned and correlated to atomic movements with the help of calculations. Interestingly, in the high-frequency region, there are several modes that soften under compression. These modes have been identified as internal vibrations of the IO3 coordination polyhedron. Their unusual behavior is a consequence of the changes induced by pressure in the coordination sphere of iodine, which gradually change from a threefold coordination to an almost sixfold coordination under compression. The coordination change is favored by the decrease of the stereoactivity of the iodine lone electron pair so that likely a real sixfold coordination is attained after a first-order phase transition previously reported to occur above 21 GPa. The strong nonlinear behavior found in Raman-active modes as well as in theoretically calculated elastic constants has been discovered to be related to the occurrence of two previously unreported isostructural phase transitions at 1.5-2.0 and 5.7-6.0 GPa as shown by dynamic instabilities close to the Brillouin zone center., This work was supported by the Spanish Ministry of Science, Innovation and Universities, the Spanish Research Agency (AEI), the European Fund for Regional Development (ERDF, FEDER) under grants MAT2016-75586-C4-1/2/3-P, PID2019-106383GB-C41/42/43, and RED2018-102612-T (MALTA Consolider-Team Network), and the Generalitat Valenciana under grant Prometeo/2018/123 (EFIMAT). A.L. and D.E. would like to thank the Generalitat Valenciana for the Ph.D. fellowship GRISOLIAP/2019/025).

Todo profesor tiene en mente varios interrogantes. Se pregunta sobre si se habrán alcanzados los objetivos previstos, sobre si los alumnos cumplen con las expectativas, qué recursos utilizo para evaluarlos. Clasificando a los alumnos por su rendimiento académico, se suelen separar entre alto y bajo rendimiento, sin más matices. En este estudio pretendemos conocer los factores que afectan el rendimiento académico y los rasgos de los profesores preferidos por los alumnos, que permiten una mayor comunicación en clase. Para ello se aplicó un cuestionario a una muestra de 176 alumnos de último ciclo de Educación Primaria (11-12 años) y primer ciclo de Educación Secundaria (12-13 años) en la ciudad de Albacete (España). Los resultados son claros, los alumnos/as prefieren las siguientes cualidades entre sus profesores/as: la simpatía, el buen humor, la realización de actividades complementarias y extraescolares, la comprensión, la motivación y el respeto. Y el rasgo menos preferido fue la exigencia.

The aim of this study is to evaluate children in middle childhood with clubfoot treated with Ponseti method vs posterior-only release and to compare their results to a control group with 4 modules (physical examination, gait study, radiographic measurements, and questionnaires). From 01/01/2004 until 01/01/2009, 31 children (45 feet) were treated with the posterior-only release protocol and 22 patients (34 feet) were treated with the Ponseti method. In 2016, patients were evaluated and compared with 25 children without neuromuscular disorders. Parents completed 3 outcome questionnaires. Radiographs evaluated residual deformity and osteoarthritis. A physical examination and a 3-dimensional gait analysis were performed to evaluate range of motion, kinematic, and kinetic data. Recurrence rate was similar between treatment groups; however, type of surgery to treat residual deformity was more aggressive in the posterior-only release (91% required major surgery), p?=?.024. Radiographic examination showed similar residual deformity with greater hindfoot varus in posterior-only release (68%), p?=?.02. Reduced cadence, increased stance dorsiflexion, calcaneus gait and forced eversion prior to swing were the main characteristics of gait in posterior-only release. Four (11%) feet treated with posterior-only release vs 11 (33%) feet treated with Ponseti method had a normal gait, p?=?.016. Our study showed that biomechanical function and long-term outcomes of children in middle childhood treated with the Ponseti method more closely compare with healthy individuals than those treated using posterior-only surgical technique. Copyright © 2020 the American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

[EN] Crop classification based on satellite and aerial imagery is a recurrent application in remote sensing. It has been used as input for creating and updating agricultural inventories, yield prediction and land management. In the context of the Common Agricultural Policy (CAP), farmers get subsidies based on the crop area cultivated. The correspondence between the declared and the actual crop needs to be monitored every year, and the parcels must be properly maintained, without signs of abandonment. In this work, Sentinel2 time series images and 4-band Very High Resolution (VHR) aerial orthoimages from the Spanish National Programme of Aerial Orthophotography (PNOA) were combined in a pre-trained Convolutional Neural Network (CNN) (VGG-19) adapted with a double goal: (i) the classification of agricultural parcels in different crop types; and (ii) the identification of crop condition (i.e., abandoned vs. non-abandoned) of permanent crops in a Mediterranean area of Spain. A total of 1237 crop parcels from the CAP declarations of 2019 were used as ground truth to classify into cereals, fruit trees, olive trees, vineyards, grasslands and arable land, from which 80% were used for training and 20% for testing. The overall accuracy obtained was greater than 93% both, at parcel and area levels. Olive trees were the least accurate crop, mostly misclassified with fruit trees, and young vineyards were slightly confused with cereal and arable land. In the assessment of crop condition, only 9.65% of the abandoned plots were missed (omission errors), and 7.21% of plots were over-detected (commission errors), having a 99% of overall accuracy from a total of 1931 image subset samples. The proposed methodology based on CNN is promising for its operational application in crop monitoring and in the detection of abandonments in the context of CAP subsidies, but a more exhaustive number of training samples is needed for extension to other crop types and geographical areas., This research has been funded by the Conselleria d'Agricultura, Medi Ambient, Canvi Climàtic i Desenvolupament Rural, Generalitat Valenciana, throught the nominative line S847000. The authors also thank the Institut Cartogràfic Valencià for providing very high resolution aerial imagery data of the study area.

[EN] Divalent metal carbonates play an important role in Earth's carbon cycle, but the effect of chemical substitution is still poorly known. In this work, we have studied the structural and vibrational properties of natural mineral gaspeite (Ni0.75Mg0.22Ca0.03CO3) under high pressure and temperature using in situ synchrotron X-ray diffraction and Raman spectroscopy in diamond-anvil cells. These experiments have been complemented by ab initio simulations. Synchrotron high-pressure XRD measurements at room temperature using He as the pressure transmitting medium have shown that the calcite-type structure is stable up to 23.3 GPa. A bulk modulus at zero pressure of B-0 = 105(2) GPa with B-0' = 7.4(3) has been obtained from the experimental equation of state. This result indicates that gaspeite is the most incompressible of all the divalent metal carbonates. The axial compressibilities in gaspeite have a high anisotropy, with the c axis about 3 times more compressible than the a axis. We have followed under pressure the Raman modes of gaspeite up to 19 GPa. Moreover, Ni0.75Mg0.22Ca0.03CO3 compressed at 5.5 GPa has been heated up to 840 K, revealing that this carbonate is stable in these conditions. The equation of state of magnesian gaspeite at this temperature has been determined. Our ab initio calculations on NiCO3 at zero pressure and 5.5 GPa have allowed us to estimate the thermal expansion coefficients. The obtained values show that the anisotropy in the thermal expansion is comparable to that found in axial compressibility., Authors thank the financial support from the Spanish Ministerio de Ciencia, Innovacion y Universidades (MICINN) under projects MALTA Consolider Ingenio 2010 network (MAT2015-71070-REDC) and PGC2018-097520-A-I00 (co-financed with EU FEDER funds) and from the Generalitat Valenciana under project PROMETEO/2018/123. D.S.-P. and A.O.R. acknowledge the financial support of the Spanish MINECO for the RyC-2014-15643 and RyC-2016-20301 Ramo ' n y Cajal Grants, respectively. C.P. and O.G. acknowledge the financial support from the Spanish Ministerio de Economia y Competitividad (MINECO projects FIS2017-83295-P and MAT2016-75586-C4-1-P/2-P, respectively). We thank David Vie for carrying out the GTA measurements. Authors also thank Dr. Nicolescu and the Mineralogy and Meteroritic Department of the Yale Peabody Museum of Natural History for providing the mineral samples and ALBA-CELLS synchrotron for providing beamtime under experiment 2018082948. A.O.R. thanks the MALTA Consolider Supercomputing Centre and Compute Canada for computational resources. British Crown Owned Copyright 2020/AWE. Published with permission of the Controller of Her Britannic Majesty's Stationery Office.

We report the findings of a diachronic study of 100 research paper abstracts published in four different periods (from 1943 to 2018) in Monthly Notices of the Royal Astronomical Society, one of the most prestigious astrophysics journals written in English. Our main results show that research paper abstracts have evolved over time in the sense that they have become longer, more informative and more precise. They also reveal an overall increase in the number of authors, active and modal verbs, self-mentions and compound groups per total number of words. Likewise, compound structures are becoming more and more complex. These outcomes may be explained in terms of a rising collaboration scenario and an attempt to increase authors’ visibility.

[EN] High pressure X-ray diffraction, Raman scattering, and electrical measurements, together with theoretical calculations, which include the analysis of the topological electron density and electronic localization function, evidence the presence of an isostructural phase transition around 2 GPa, a Fermi resonance around 3.5 GPa, and a pressure-induced decomposition of SnSb2Te4 into the high-pressure phases of its parent binary compounds (alpha-Sb2Te3 and SnTe) above 7 GPa. The internal polyhedral compressibility, the behavior of the Raman-active modes, the electrical behavior, and the nature of its different bonds under compression have been discussed and compared with their parent binary compounds and with related ternary materials. In this context, the Raman spectrum of SnSb2Te4 exhibits vibrational modes that are associated but forbidden in rocksalt-type SnTe; thus showing a novel way to experimentally observe the forbidden vibrational modes of some compounds. Here, some of the bonds are identified with metavalent bonding, which were already observed in their parent binary compounds. The behavior of SnSb2Te4 is framed within the extended orbital radii map of BA(2)Te(4) compounds, so our results pave the way to understand the pressure behavior and stability ranges of other "natural van der Waals" compounds with similar stoichiometry., This work has been performed under financial support from the Spanish MINECO under Project MALTA-CONSOLIDER TEAM network (RED2018-102612-T) and Project FIS2017-83295-P, from Generalitat Valenciana under Project PROMETEO/2018/123. This publication is a product of the "Programa de Valoracion y Recursos Conjuntos de I+D+i VLC/CAMPUS and has been financed by the Spanish Ministerio de Educacion, Cultura y Deporte, as part of "Programa Campus de Excelencia Internacional". Supercomputer time has been provided by the Red Espanola de Supercomputacion (RES) and the MALTA cluster. J.A.S. acknowledges a "Ramon y Cajal" fellowship (RYC-2015-17482) for financial support, and E.L.D.S. acknowledges Marie Sklodowska-Curie Grant No. 785789-COMEX from the European Union's Horizon 2020 research and innovation program. We also thank ALBA synchrotron and DIAMOND light source for funded experiments.

Perylene‐fused, aggregation‐free polycyclic aromatic hydrocarbons with partial zigzag periphery (ZY‐01, ZY‐02, and ZY‐03) were synthesized. X‐ray crystallographic analysis reveals that there is no intermolecular π–π stacking in any of the three molecules, and as a result, they show moderate‐to‐high photoluminescence quantum yield in both solution and in the solid state. They also display the characteristic absorption and emission spectra of perylene dyes. ZY‐01 and ZY‐02 with a nearly planar π‐conjugated skeleton exhibit amplified spontaneous emission (ASE) when dispersed in polystyrene thin films. Solution‐processed distributed feedback lasers have been fabricated using ZY‐01 and ZY‐02 as active gain materials, both showing narrow emission linewidth (

[EN] Polycaprolactone/Graphene oxide (PCL/GO) composites are shown to be promising substrates for tissue engineering as their degradation behavior is a key aspect in this type of application. The present paper studies the effect of different GO contents (0.1, 0.2 and 0.5 wt%) of PCL/GO composites on accelerated hydrolytic degradation at pH 13 and pH 1. Degradation kinetics at pH 13 is strongly affected by GO content, and speed up at higher percentages. The composite with 0.5 wt% of GO was completely degraded in 72 hours, while degradation at pH 1 presents a different profile and seems to have an induction period that lasts more than 1500 hours. Morphological changes, molecular weight distribution, weight loss, degree of swelling and calorimetric properties were obtained as a function of degradation time. According to the results obtained, the addition of small percentages of GO significantly influences the degradation behavior of the composites acting as degradation modulators., Isabel Castilla-Cortazar and Alberto J. Campillo-Fernandez are grateful for the support of the Spanish Ministry of Science, Innovation and Universities, through RTI2018-095872-B-C22/ERDE Ana Vidaurre would like to express her gratitude for the support of the Spanish Ministry of Science and Education, through the MAT2016-76039-C4-1-R Project, and also the support from CIBER-BBN, an initiative funded by the Sixth National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CII3ER Actions financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund.

We report a joint experimental and theoretical study of the structural, vibrational, and electronic properties of layered monoclinic arsenic sulfide crystals (α-As2S3), aka mineral orpiment, under compression. X-ray diffraction and Raman scattering measurements performed on orpiment samples at high pressure and combined with ab initio calculations have allowed us to determine the equation of state and the tentative assignment of the symmetry of many Raman-active modes of orpiment. From our results, we conclude that no first-order phase transition occurs up to 25 GPa at room temperature; however, compression leads to an isostructural phase transition above 20 GPa. In fact, the As coordination increases from threefold at room pressure to more than fivefold above 20 GPa. This increase in coordination can be understood as the transformation from a solid with covalent bonding to a solid with metavalent bonding at high pressure, which results in a progressive decrease of the electronic and optical bandgap, an increase of the dielectric tensor components and Born effective charges, and a considerable softening of many high-frequency optical modes with increasing pressure. Moreover, we propose that the formation of metavalent bonding at high pressures may also explain the behavior of other group-15 sesquichalcogenides under compression. In fact, our results suggest that group-15 sesquichalcogenides either show metavalent bonding at room pressure or undergo a transition from p-type covalent bonding at room pressure towards metavalent bonding at high pressure, as a precursor towards metallic bonding at very high pressure., Authors thank the financial support from Spanish Ministerio de Economia y Competitividad (MINECO) through MAT2016-75586-C4-2/3-P and FIS2017-83295-P and from Generalitat Valenciana under project PROMETEO/2018/123-EFIMAT. ELDS acknowledges the European Union Horizon 2020 research and innovation programme under Marie Sklodowska-Curie for grant agreement No. 785789-COMEX. JAS also acknowledges Ramón y Cajal program for funding support through RYC-2015-17482. AM, SR and ELDS thank interesting discussions with J. Contreras-García who taught them how to analyze the ELF. Finally, authors thank ALBA Light Source for beam allocation at beamline MSPD (Experiment No. 2013110699) and acknowledge computing time provided by MALTA-Cluster and Red Española de Supercomputación (RES) through computer resources at MareNostrum with technical support provided by the Barcelona Supercomputing Center (QCM-2018-3-0032).

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited., Trojan asteroids are small bodies orbiting around the L4 or L5 Lagrangian points of a Sun-planet system. Due to their peculiar orbits, they provide key constraints to the Solar System evolution models. Despite numerous dedicated observational efforts in the last decade, asteroid 2010 TK7 has been the only known Earth Trojan thus far. Here we confirm that the recently discovered 2020 XL5 is the second transient Earth Trojan known. To study its orbit, we used archival data from 2012 to 2019 and observed the object in 2021 from three ground-based observatories. Our study of its orbital stability shows that 2020 XL5 will remain in L4 for at least 4 000 years. With a photometric analysis we estimate its absolute magnitude to be Hr=18.58+0.16−0.15, and color indices suggestive of a C-complex taxonomy. Assuming an albedo of 0.06 ± 0.03, we obtain a diameter of 1.18 ± 0.08 km, larger than the first known Earth Trojan asteroid. © The Author(s) 2022., The work of TS-R was carried out through grant APOSTD/2019/046 by Generalitat Valenciana (Spain). This work was (partially) funded by the Spanish MICIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” by the “European Union” through grant RTI2018-095076-B-C21, and the Institute of Cosmos Sciences University of Barcelona (ICCUB, Unidad de Excelencia ‘María de Maeztu’) through grant CEX2019-000918-M. P-YL acknowledges NEO-MAPP project under H2020-SPACE-2019 GA 870377. PGB, and ACB acknowledge funding from the Spanish MICINN project RTI2018-099464-B-I00. AA-C acknowledges support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). DO was supported by National Science Centre, Poland, grants numbers 2017/26/D/ST9/00240 and 2017/25/B/ST9/00740. The Catalina Sky Survey is funded by NASA’s Planetary Defense Coordination Office, under grant 80NSSC18K1130. The Joan Oró Telescope (TJO) of the Montsec Observatory (OdM) is owned by the Catalan Government and operated by the Institute for Space Studies of Catalonia (IEEC). MD acknowledges funding from NASA NEOO grant 80NSSC21K0045 in support of the Second Lunation NEO Follow-up. These results made use of the Lowell Discovery Telescope (LDT) at Lowell Observatory. Lowell is a private, non-profit institution dedicated to astrophysical research and public appreciation of astronomy and operates the LDT in partnership with Boston University, the University of Maryland, the University of Toledo, Northern Arizona University, and Yale University. The Large Monolithic Imager (LMI) was built by Lowell Observatory using funds provided by the National Science Foundation (AST-1005313). Operation of the Pan-STARRS telescope is supported by the National Aeronautics and Space Administration under Grant No. 80NSSC18K0971 issued through the SSO Near-Earth Object Observations Program.

The detection of methane emissions from fossil fuel production activities, such as oil and gas extraction and coal mining, has been identified as a key means for the reduction of greenhouse gas emissions to the atmosphere. Several types of optical satellite sensors have recently been shown to be instrumental for this task. Spaceborne imaging spectrometers belong to this group. These instruments measure the solar radiation reflected by the Earth in hundreds of spectral channels in the 400-2500 nm spectral range with a typical spectral resolution of 10 nm and a spatial resolution of 30 m. The Italian PRISMA mission is the first system of this type providing data openly to the international scientific community. In this work, we evaluate the potential of PRISMA for methane mapping. Our retrieval of methane concentration enhancements is based on a matched-filter based algorithm applied to the 2300 nm spectral region containing methane absorption bands. We perform a simulation-based sensitivity analysis to assess the retrieval performance for different sites. The impact on the retrieval of uncertainties in PRISMA's spectral response and of different illumination conditions has also been evaluated. We find that brightness and homogeneity of the surface are major drivers for the detection and quantification of methane plumes with PRISMA, with precision errors ranging from 61 to 197 ppb in the evaluated images. The potential of PRISMA for methane mapping is further illustrated by real plume detections at different methane hotspot regions, including oil and gas extraction fields in Algeria, Turkmenistan, and the Permian Basin (USA) as well as the coal mines in the Shanxi region in China. Our study reports several important findings regarding the potential and limitations of PRISMA for methane mapping, most of which can be extrapolated to upcoming satellite imaging spectroscopy missions.

El estudiante se familiarizará con el concepto de computación cuántica y considerará aplicaciones para la solución eficiente de problemas relevantes en su ámbito de especialización, como son problemas de enrutamiento de paquetes de datos o problemas relacionados. Tras una revisión exhaustiva de la literatura existente, se propondrá una solución eficiente a problemas de ruteo mediante una modificación del algoritmo de Grover. Esta modificación tendrá en cuenta aspectos de eficiencia en la codificación de rutas, así como particularidades del problema para tamaños intermedios. La propuesta de algoritmo será implementada en los ordenadores cuánticos de IBM en la nube Escuela Técnica Superior de Ingeniería de Telecomunicación Universidad Politécnica de Cartagena

Any early or late dynamical instability in the outer Solar system should have left their footprint on the trans-Neptunian object (TNO) populations. Here, we study the collisional and dynamical evolution of such populations numerically by an updated version of ALICANDEP, which suitably takes into account the onset of an early dynamical instability. Key parameters for collisional and dynamical evolution are chosen to match results with current observables. The new model (ALICANDEP-22) considers an original region located between 22 and 30 au, containing 20–30 M⊕ from which bodies are either dynamically ejected from the region or implanted into the current plutinos and hot classical trans-Neptunian belt. An in situ population of objects is also present since the beginning, corresponding to the current cold-classical population. Collisional and dynamical evolution is allowed starting from initial conditions accounting for streaming instability models and observational constraints. ALICANDEP-22 successfully reproduces observational constraints as well as the shape of the size-frequency distribution expected for the Trojan population. The model concludes that Arrokoth is likely a primordial body but cannot be conclusive on the origin of comet 67P/Churyumov–Gerasimenko. The current presence of bodies larger than Pluto in the outer TNO population – waiting to be discovered – is compatible with the initial distributions that allow the model to match current constraints. © 2022 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society., PGB and ACB acknowledge funding by the Spanish Ministerio de Investigación, Ciencia e Innovación through project RTI2018-099464-B-I00 ‘Retos de la Sociedad’ (2018 call). JC acknowledge the University of Surrey and its Physics department for giving him the opportunity that allowed him to stay at the University of Alicante (UA) and to collaborate to this work during part of 2020. AAC acknowledges UA grant UATALENTO18-02 and from the State Agency for Research of the Spanish MCIU through the ‘Center of Excellence Severo Ochoa’ award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). We thank the International Space Science Institute (ISSI Bern), who supported the OCEOSS project where some of this work was discussed.

In this paper, velocity level difference through L-shaped plates is studied using finite element analysis (FEA). Validation is performed using experimental measurements and comparing different finite elements models. The velocity level difference between the source and receiving plate is used to study how vibration flows for third-octave frequency bands, within the frequency range 40-3150 Hz. The influence of different types of geometry, material properties, meshes, types of excitations and the incorporation of an elastic layer, simulating a floating floor, were studied. The use of finite elements models with 2D elements proved to be adequate and a good approximation was obtained from both experimental and finite element analysis results.

The dynamic elastic modulus is an important parameter for the study of solid mechanical elements. Even though there exist several well-established standardized methods that allow determining this parameter under a state of simple stresses, some of these may require sophisticated laboratory equipment or involve the use of multiple devices (impulser, sensor transducer…). The main purpose of this work is to propose an alternative approach that uses a single electrodynamic actuator both as an impulse exciter and vibration sensor simultaneously. By generating a random signal excitation and measuring the electrical input impedance of the actuator when coupled to a beam-type cylindrical element, the fundamental flexural mode of vibration of the latter can be identified and the dynamic elastic modulus of its material determined in a simple and straightforward manner. Preliminary experiments were performed over different size beams with rectangular cross-sections made of natural stone, marble, wood, and aluminium. Results were compared to those obtained using the standardized procedure described in the ASTM E1876 for the same specimens, these showing a good agreement in terms of dynamic elastic modulus.

Este manuscrito se ubica dentro de la electrónica molecular. Estudios recientes realizados en esta rama de nanotecnología han conseguido demostrar que los disolventes orgánicos como benceno, tolueno y ciclohexano no se evaporan totalmente sobre las superficies de oro, y por lo tanto contribuyen en las medidas de trasporte electrónico cuando las moléculas de interés van disueltas en ellos. Por ese motivo presentamos aquí un modelo sobre la evaporación de los disolventes en superficies, así como simulaciones de experimentos de contactos moleculares basados en la técnica BJ. Estos modelos han sido realizados mediante simulaciones de Dinámica Molecular. Por otro lado y para poder revelar que relación hay entre transporte electrónico y como se ha depositado la molécula sobre los electrodos, presentamos un estudio de conductancia basado en la Density Functional Theory sobre las geometrías obtenidas mediante dinámica molecular. Finalmente, gracias a la combinación de estas dos técnicas, hemos conseguido modelizar la evaporación y desvelar la relación entre geometría y conductancia en contactos moleculares.

Esta investigación de diseño cuasiexperimental se centra en analizar las actitudes hacia la práctica de las habilidades gimnásticas y acrobáticas en una muestra de alumnos de Educación Secundaria, según los estilos de enseñanza aplicados. El desarrollo de las destrezas gimnásticas se plantea a través de dos métodos de enseñanza diferentes; por un lado, una enseñanza tradicional utilizando el mando directo y la asignación de tareas y, por otro lado, un método participativo, como es el caso del estilo de la microenseñanza. Los resultados evidencian que a través de las metodologías participativas se favorece la predisposición y satisfacción hacia las prácticas gimnásticas, así como la mejora de actitudes colaborativas; mientras que a través de los métodos tradicionales se fomenta la percepción de la mejora del aprendizaje motor y la corrección de los propios errores técnicos. Por lo tanto, el método de enseñanza adoptado por el profesorado podrá condicionar la relación de éste con los distintos elementos del contexto didáctico, de forma que marcará las propias relaciones entre los mismos. Para potenciar ambientes de aprendizaje óptimos el profesorado deberá dominar, combinar y aplicar diferentes estilos de enseñanza tras establecer un análisis previo de la situación dentro de la convivencia del aula. This quasi-experimental research focuses on analysing attitudes towards the practice of gymnastic and acrobatic skills in a sample of High School students, according to the teaching styles applied. The development of gymnastic skills is approached through two different teaching methods; on the one hand, traditional teaching: direct command and assignment of tasks and, on the other hand, a participative style: microteaching. The results show that through participatory methodologies, predisposition and satisfaction towards gymnastic practices are favoured, as well as the improvement of collaborative attitudes; while through traditional styles, the perception of the improvement of motor learning and the correction of one’s own mistakes are encouraged. Therefore, the teaching style adopted by the teacher may condition the relationship of the latter with the different elements of the didactic context, in such a way that it will mark the relationships between them. To promote optimal learning environments, teachers must master, combine, and apply different teaching styles after establishing a prior analysis of the situation within the classroom. El presente trabajo ha contado con una ayuda del Programa de Redes de investigación en docencia universitaria del Instituto de Ciencias de la Educación de la Universidad de Alicante (convocatoria 2021-22). Ref.: [5452].