Technical University of Madrid

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    Bright future by controlling alpha/gamma phase junction of formamidinium lead iodide doped by imidazolium for solar cells: Insight from experimental, DFT calculations and SCAPS simulation

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    In this study, we investigated the potential of Formamidinium lead iodide (FAPbI3) thin films as an absorber layer in perovskite-based solar cells, due to their good optoelectronic properties. Specifically, we investigated the effects of doping FAPbI3 with imidazolium (IM) at various percentages (ranging from 0% to 8%) on the stability and phase of the material at the α/δ phase junction. To do this, we used a range of analytical techniques, including x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence spectroscopy (PL), and UV-visible spectroscopy. Our findings showed that 6% IM-doped FAPbI3 led to homogeneous perovskite films with a stable α-phase perovskite, large grain size, and no holes. We confirmed these results via Density Functional Theory (DFT) studies. Additionally, we analyzed the impact of 6% IM-doped FAPbI3 in the context of solar cell applications using SCAPS simulations. We introduced a stacked layer-based perovskite structure (FTO/TiO2/FAPbI3/MAPbI3/Spiro − MeoTAD/Au) and found that the device had a high power conversion efficiency (PCE) of 26.10%, with a fill factor (FF) of 88%, open-circuit voltage (VOC) of 1.18 V, and short-circuit current density (JSC) of 25.18 mA/cm2

    Effect of ice/dirt on cup anemometer rotors

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    The effect of ice/dirt on the cup anemometer rotors was experimentally studied. Different anemometer rotors with plastic parts that simulate the ice/dirt accumulation at the cups' intrados (that is, in the cups' inside) were tested. The results clearly show a loss of performance due to this effect. This loss of performance was translated into terms of wind speed underestimation. The results indicate a 10% underestimation when 50% of the cups’ intrados are occupied by ice/dirt. The harmonic analysis seems to indicate that this accumulation of ice/dirt is reflected in the third harmonic term of the rotational speed, although in this case the results are not conclusive

    On the UPMSat-2 magnetometer’s calibration methods performance comparison for poorly conditioned datasets

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    This article summarises the work related to the calibration methodology of the Attitude, Control and Determination Subsystem (ADCS) sensors used in the UPMSat-2 mission project, a 50 kg satellite designed and manufactured by the Universidad Politécnica de Madrid. The ADCS sensors are two fluxgate magnetometers whose calibration is essential to obtain correct measurements. Since the calibration process must be performed once the magnetometers are integrated in the satellite, the range of movements to obtain a representative set of measurements distributed in space is limited. n the present work, several geometric adjustment algorithms are evaluated in order to find the best mathematical structure for this particular problem: underconditioned measurements in the calibration scenarios. The magnetometer data obtained in the satellite integration test are used, together with the selected fitting algorithm, to obtain the calibration parameters of the sensors

    Objetos tenaces : adaptive reuse en Meatpacking, 1970–1985

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    OBJETOS TENACES versa sobre la práctica del adaptive reuse (la “reutilización adaptativa”, la reconversión) explicado a través del fenómeno de ruptura, suspensión y reconfiguración de vínculos que el objeto arquitectónico tiene con respecto a su medio económico, sociocultural, normativo y de utilitas. Se trata de un fenómeno en tres fases, muy próximo al mecanismo empleado por el readymade y por el display, que en arquitectura parte de la crisis que supone un cambio de circunstancias, un desarraigo del objeto respecto de su ámbito anterior. El mecanismo tiene vocación de intervención mínima, desde un posicionamiento actual que comprende el mundo construido como una realidad “ya hecha”, y donde las operaciones de proyecto son acciones de transformación que llevan de una situación de obsolescencia a otra de vigencia renovada, es decir, de una realidad completa a otra igualmente completa. Para ello, la investigación se sirve de tres ejemplos de un mismo entorno geográfico (el área en torno a Meatpacking, en el lado oeste del bajo Manhattan, Nueva York) y temporal (las últimas décadas del siglo XX, en las que los casos se solapan a pesar de tener desarrollos cronológicos diversos). Bell Telephone Laboratories, The West Side Improvement y The National Biscuit Company, reconvertidos a Westbeth, a The High Line y a Chelsea Market, construyen juntos el argumento por suma de conceptos, por adición de fenómenos, estudiando las cualidades y las circunstancias que hacen posible la continuidad de las estructuras, es decir, su supervivencia. El texto forma un corpus que proporciona algunas de las claves del objeto denominado como tenaz a través del análisis sincrónico del antes y el después de su puesta en crisis. A tal efecto, se exponen una serie de figuras razonadas entre las cuales figuran el lijado del barniz, los hilos compartidos, la máscara, la momificación y la vitrina, el puente sobre le desfiladero, el enfriamiento, o las reliquias, incrustaciones y adherencias, todas ellas encaminadas a explicar el proceso de renovación del artefacto como un cambio en el sentido, en el significado, y no tanto en lo material. Entre las consideraciones de la tesis está, por un lado, el carácter relativo del término tenacidad, concepto que define a los objetos que se encuentran y se reconocen en su idoneidad, que tienen capacidad de adaptación, y que precisan finalmente de grandes dosis de pragmatismo para su reconfiguración, siendo todas éstas condiciones necesarias pero sólo suficientes a posteriori. Por otro lado, el texto reflexiona acerca del intangible que comparten todos los objetos así llamados y que consiste en la condición, quizá formidable, de ser reconocibles por parte de los sucesivos intervinientes de su historia, convencidos de que su renovación supone una oportunidad; su desaparición, una pérdida. Finalmente, la investigación apunta hacia el concepto de anacronismo como justificación para los objetos que se demuestran adaptables a épocas sucesivas, y que encajan en el tiempo de forma compleja. ABSTRACT TENACIOUS OBJECTS deals with the practice of the adaptive reuse explained by means of the phenomenon of rupture, suspension and reconfiguration of links that the architectural object has vis-à-vis its economic, socio-cultural and regulatory environment, and its utilitas. It is a phenomenon structured in three stages, very close to the mechanism used by the readymade and by the display, which in architecture arise from the crisis that leads to a change in circumstances, an alienation of the object regarding its previous environment. The mechanism aims to the minimum intervention, from a current positioning which understands the world built as a reality “already made”, and where the operations of the project are transformative actions that take us from a situation of obsolescence to a situation of renewed validity, that is, from a complete reality to one just as complete. For this purpose, the research makes use of three examples in the same geographical area (the Meatpacking Discrict, in the Lower West Side of Manhattan, New York) and the same period (the last decades of the 20th century, in which the cases overlap in spite of their diverse chronological developments). Bell Telephone Laboratories, The West Side Improvement and The National Biscuit Company, reconverted into Westbeth, The High Line and Chelsea Market, make up, together, the argument as a sum of concepts, and addition of phenomena, studying the qualities and circumstances which make the continuity of the structures possible, that is, their survival. The text forms a corpus that provides some of the keys of the so-called tenacious object by means of the synchronic analysis of before and after its crisis. To this end, a series of reasoned figures is presented, including the sanding of varnish, the shared threads, the mask, the mummification and the display cabinet, the bridge over the gorge, cooling, or the relics, incrustations and adherences, all of them aimed at explaining the renovation process of the artifact as a change in the sense and the meaning, rather than the material. The considerations of this dissertation include, on the one hand, the relative nature of the term tenacity, a concept which defines the objects found and recognized in their suitability, that are capable of adapting and which finally require large doses of pragmatism for their reconfiguration, all these conditions being necessary but only sufficient a posteriori. On the other hand, the text reflects on the intangible shared among all the so-called objects, and which consists of the condition, perhaps extraordinary, of being recognized by the subsequent interveners of their history, convinced that their renovation represents an opportunity; their disappearance, a loss. Finally, the dissertation studies the concept of anachronism as a justification for the objects that prove to adapt to subsequent periods, and which fit in time in a complex manner

    Bright future by enhancing the stability of methylammonium lead triiodide perovskites thin films through Rb, Cs and Li as dopants

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    This paper deals with the doping of methylammonium lead iodide (MAPbI3) with small amounts of rubidium (Rb), lithium (Li) and caesium (Cs) to improve the crystallisation of MAPbI3 films. Doping significantly increases the peak the (110) diffraction peak, which is related to enhanced crystallisation. The peak located at 148 cm−1 dominates all the Raman spectra in the doped MAPbI3, which is characterised by a central vibrational band corresponding to the symmetric vibration of the anion sublattice. The microstructures of these improved films are characterised by large grain sizes and a uniform surface morphology with no pinholes. Consequently, these films are suitable for high-performance optoelectronic devices. The influence of Li, Rb, and Cs doping on the photophysical properties of MAPbI3 perovskite films is investigated by a photoluminescence analysis. Doping with 5% Li cations increases photoluminescence emissions due to the reduction in the density of trap states. These findings provide fundamental insights into the crystallisation process of MAPbI3 and offer new approaches for developing stable and high-performance devices based on MAPbI3

    Delafossite as hole transport layer a new pathway for efficient perovskite-based solar sells: Insight from experimental, DFT and numerical analysis

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    Herein, we propose a successful technique to produce delafossite materials that can be applied as Hole Transport Layer (HTL) in inorganic lead halide Perovskite solar cells (PSCs). The delafossite CuMO2, where M=Al,Ga,Fe,Cr,Ni,Co,Cr types were investigated the M cation effect on the crystal structure, morphology, and optical properties. These properties were investigated using X-ray, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV visible spectroscopy. The XRD results confirmed their hexagonal and rhombohedral-like structure, where the SEM image of CuMO2 shows the good formation of delafossite layers. The optical band gap of CuMO2 varies from 2.2Â eV to 2.99Â eV, which is well in line with the literature. Similarly, we also perform the density functional theory (DFT) calculations for delafossite layers to find their electronic properties of them. Based on experimental and DFT calculations, we performed the numerical analysis in SCAPS-1D software on standard solar cell structure (Spiro-OMeTAD/MAPbI3/TiO2) and replaced Spiro-OMeTAD with all the deposited delafossite layers. Our numerical analysis found that HTL shows the highest power conversion efficiency (PCE) of 22.90. The proposed work can give a good direction for manufacturing to improve the performance of Perovskite-based solar cells (PSCs)

    Entrepreneurial innovativeness: When too little or too much agglomeration hurts

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    This study sheds light on the relationship between agglomeration, entrepreneurs' internal resources and capabilities, and new ventures' innovativeness using a multilevel framework. We argue that the urban agglomeration of economic agents within a country has an inverted U-shaped relationship with new ventures' innovativeness, suggesting that both insufficient and excessive agglomeration might be detrimental to entrepreneurial innovativeness. Additionally, we perform interactions between individual level factors and urban agglomeration to examine the differential effects of entrepreneurs' internal resources and capabilities. Results confirm our hypothesising that the geographical concentration of economic agents within a country exerts an inverted U-shaped influence on new ventures' innovativeness. Furthermore, we find that entrepreneurs with higher levels of education or prior entrepreneurial experience are better equipped to benefit from agglomeration and to mitigate its negative effects; in contrast, at low levels of agglomeration, entrepreneurs with lower resources exhibit increasing marginal returns. Entrepreneurs in contact with other entrepreneurs are better positioned to deal with agglomeration externalities although their benefits and drawbacks are intensified. Our research contributes to the understanding of agglomeration externalities and entrepreneurial innovativeness, its non-linear dynamics and differential effects

    Bright future by enhancing the stability of methylammonium lead triiodide perovskites thin films through Rb, Cs and Li as dopants

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    This paper deals with the doping of methylammonium lead iodide (MAPbI3) with small amounts of rubidium (Rb), lithium (Li) and caesium (Cs) to improve the crystallisation of MAPbI3 films. Doping significantly increases the peak the (110) diffraction peak, which is related to enhanced crystallisation. The peak located at 148 cm−1 dominates all the Raman spectra in the doped MAPbI3, which is characterised by a central vibrational band corresponding to the symmetric vibration of the anion sublattice. The microstructures of these improved films are characterised by large grain sizes and a uniform surface morphology with no pinholes. Consequently, these films are suitable for high-performance optoelectronic devices. The influence of Li, Rb, and Cs doping on the photophysical properties of MAPbI3 perovskite films is investigated by a photoluminescence analysis. Doping with 5% Li cations increases photoluminescence emissions due to the reduction in the density of trap states. These findings provide fundamental insights into the crystallisation process of MAPbI3 and offer new approaches for developing stable and high-performance devices based on MAPbI3

    Integrating lived experience: Qualitative methods for addressing energy poverty

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    This article presents a systematic literature review focused on the use of Qualitative Research Methods to study and characterise energy poverty. Qualitative Research Methods (QRM) influence the lived experiences associated with this issue and provide information that is not accessible from a quantitative point of view or from conventional databases. The introduction of these methodologies has often been carried out without a proper framework applied to energy poverty or even without contextualizing the disciplines or describing the methods used. In this study, a systematic literature review has been carried out on the qualitative nature of the phenomenon. The results obtained are presented grouped into three areas: objectives pursued by the research and QRM used to achieve them; data collection techniques and types of analysis carried out; characterisation and recruitment of participants in the different studies. All the articles included in the review have been considered relevant in their contribution to the characterisation of energy poverty through the integration of qualitative methodologies. This study aims to promote knowledge about qualitative research methods and their correct application within the study of energy poverty

    Aplicación de la espectroscopia de infrarrojo cercano (NIRS) para la caracterización y evaluación de la calidad del corcho utilizado en la fabricación de tapones

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    El objetivo principal de la presente tesis doctoral es evaluar el potencial de la espectroscopia de infrarrojo cercano (NIRS) como herramienta para el control de calidad del granulado y planchas de corcho empleados en la fabricación de tapones. El sector del vino tiene unos estándares de calidad y exigencias elevadas que se trasladan hasta los tapones de corcho, lo que exige llevar a cabo rigurosos controles de calidad sobre los mismos. Los análisis de referencia empleados habitualmente son fiables, sin embargo, suelen ser costosos y lentos. Por ello, en este contexto la tecnología NIRS es una herramienta que puede ser de gran ayuda para el sector, al tratarse de una técnica rápida, económica y con resultados ya demostrados previamente, tanto en el sector forestal como especialmente en el sector agroalimentario. Para lograr este objetivo, se llevan a cabo una serie de análisis, tanto cualitativos como cuantitativos, a partir de los 1.612 espectros de infrarrojo cercano tomados sobre diferentes muestras, todas ellas preparadas a partir de planchas de corcho pertenecientes a la Suberoteca del Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA). Por un lado, se realizan 2 análisis cualitativos, uno mediante componentes principales (PCA) y otro empleando la versión discriminante del método de los mínimos cuadrados parciales (PLS-DA), a partir de los mismos 652 espectros en ambos casos. Los espectros se adquieren mediante la fibra óptica para sólidos, tomando el espectro sobre un punto de adquisición de 0,07 cm2 en la sección transversal de la plancha de corcho. El objetivo es clasificar los espectros en corcho puro, mancha amarilla o leño. A la vista de los resultados, ambos métodos permiten clasificar espectros de secciones transversales de plancha de corcho entre corcho puro o corcho con anomalías (mancha amarilla o leño) con una fiabilidad muy alta, en particular, el PLS-DA identifica correctamente todos los espectros de validación con una sensibilidad y especificidad del 100 %. Por tanto, el PCA se confirma como un método previo o exploratorio mientras que con el PLS-DA se pueden obtener los mejores resultados. Por otro lado, se llevan a cabo 3 análisis cuantitativos mediante el método de los mínimos cuadrados parciales (PLS), empleando los 960 espectros de diferentes muestras de granulado de corcho. En concreto, 240 se utilizan para estimar el porcentaje de humedad, 360 para el porcentaje de mancha amarilla y, por último, los 360 restantes para el porcentaje de raspa. Los espectros se adquieren mediante la esfera integradora con sistema rotario que permite tomar el espectro sobre una corona circular de 35,34 cm2. En relación con el porcentaje de humedad, los resultados ponen de manifiesto la viabilidad de la tecnología NIRS para determinar la humedad en granulado de corcho con un RMSECV de 0,30 % y R2 de 0,9754. En cuanto a la mancha amarilla y la raspa (RMSECV de 1,50 % y 2,96 % y R2 de 0,9962 y 0,9853 respectivamente) los resultados abren la posibilidad de utilizar la técnica NIRS para caracterizar granulado de corcho en cualquier momento del proceso productivo. Además, permite detectar la presencia o ausencia de ambas anomalías o alteraciones con gran precisión (límite crítico de 1,49 % y 1,32 % respectivamente). En conclusión, los resultados obtenidos ponen de manifiesto que la tecnología NIRS es una herramienta eficaz para el control de calidad del corcho utilizado en la fabricación de tapones, permitiendo caracterizar la materia prima utilizada ya sean planchas de corcho o granulado. De cara a su aplicación en el futuro, es necesario desarrollar una metodología que permita sistematizar la toma de los espectros, así como la consideración de anomalías o alteraciones distintas de las consideradas en esta tesis. ABSTRACT The main objective of this doctoral thesis is to evaluate the potential of near infrared spectroscopy (NIRS) as a tool for quality control of granulate and cork planks used in the manufacture of stoppers. The wine sector has high quality standards that are transferred to cork stoppers, which require rigorous quality controls to be carried out on them. The reference methods normally used in the industry are reliable, however they are often expensive and slow. Therefore, NIRS technology is a tool that can be useful for the sector, as it is a fast, economical technique with previously demonstrated results, both in the forestry sector and especially in the food industry. To achieve this objective, a series of analyses - both qualitative and quantitative -, are carried out from the 1,612 near-infrared spectra taken on different samples, all of them prepared from cork planks of the Suberoteca at the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA). On the one hand, two qualitative analyses are carried out: one using principal components (PCA) and the other using the discriminant version of the partial least squares method (PLS-DA), from the same 652 spectra in both cases. The spectra are acquired with the fiber optic reflection probe, taking the spectrum on an acquisition point of 0.07 cm2 in the cross section of the cork plank. The objective is to classify the spectra as pure cork, yellow stain or lignified cork. Considering the results, both methods allow to classify spectra of cork plank between pure cork or cork with anomalies (yellow stain or lignified cork) with a very high reliability. In particular, the PLS-DA correctly identifies all the spectra validation test with a sensitivity and specificity of 100 %. Therefore, PCA is confirmed as a preliminary or exploratory method while PLS-DA provides the best results. On the other hand, 3 quantitative analyses are carried out using the partial least squares (PLS) method, using the 960 spectra of different samples of cork granulate. Specifically, 240 are used to estimate the moisture percentage, 360 for the yellow stain percentage and, finally, the remaining 360 for the corkback percentage. The spectra are acquired using the integrating sphere with an area of spectrum of 35.34 cm2. In relation to the moisture percentage, the results show the viability of the NIRS technology to determine the moisture in cork granulate with an RMSECV of 0.30 % and R2 of 0.9754. Regarding the yellow stain and the corkback (RMSECV of 1.50 % and 2.96 % and R2 of 0.9962 and 0.9853 respectively), the results make it possible to use the NIRS technique to characterize the cork granulate at any time during the production process. In addition, it allows detecting the presence or absence of yellow stain or corkback with great precision (critical limit of 1.49 % and 1.32 % respectively). In conclusion, the results show that NIRS technology is an effective tool for quality control of the cork used in the manufacture of stoppers, allowing the characterization of the raw material used, whether it is cork planks or granulate. Looking ahead, it is necessary to develop a methodology that allows to systematize the taking of the spectra, as well as the consideration of anomalies or alterations other than those considered in this thesis

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