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Class A audio amplifier. Design and implementation
No full textEste Trabajo de Fin de Grado se centra en el estudio, diseño y montaje de un amplificador de audio de clase A capaz de entregar una potencia eficaz de 40 W sobre una carga de 8 Ω, garantizando una alta fidelidad y una distorsión mínima. Para ello, se ha adoptado una arquitectura innovadora que, en lugar de utilizar las etapas convencionales de amplificación de tensión, emplea amplificación basada en espejos de corriente con degeneración, buscando mejorar la linealidad y reducir la saturación interna del amplificador. El diseño incluye una etapa diferencial de entrada para la conversión de señal y la implementación de una realimentación mínima, con el objetivo de optimizar la respuesta transitoria y limitar la distorsión. Se han seleccionado cuidadosamente los transistores de salida con características favorables, como un alto voltaje Early, para maximizar la impedancia de salida y mejorar la estabilidad térmica. El circuito se ha simulado y probado experimentalmente, obteniéndose resultados que cumplen con los requisitos de potencia y fidelidad previstos. Finalmente, se proponen líneas de mejora futura para optimizar la eficiencia térmica y reducir el ruido de la fuente de alimentación.This Final Degree Project focuses on the study, design, and assembly of a class A audio amplifier capable of delivering an effective power of 40 W into an 8 Ω load while ensuring high fidelity and minimal distortion. For this purpose, an innovative architecture was adopted which, instead of using conventional voltage amplification stages, employs current amplification based on degenerated current mirrors. This approach aims to improve linearity and reduce internal amplifier saturation. The design includes a differential input stage for signal conversion and implements minimal feedback to optimize transient response and limit distortion. Output transistors with favorable characteristics, such as a high Early voltage, were carefully selected to maximize output impedance and enhance thermal stability. The circuit was simulated and experimentally tested, yielding results that meet the expected power and fidelity requirements. Finally, we propose future improvements to optimize thermal efficiency and reduce power supply noise.Depto. de Estructura de la Materia, Física Térmica y ElectrónicaFac. de Ciencias FísicasTRUEunpu
Local spectral theory for subordinated operators: The Cesàro operator and beyond
No full textWe study local spectral properties for subordinated operators arising from C0-semigroups. Specifically, if T = (Tt)t≥0 is a C0-semigroup acting boundedly on a complex Banach space and Hν is the subordinated operator associated to T , where ν is a sufficiently regular complex Borel measure supported on [0,∞), it is shown that Hν does not enjoy the Single Valued Extension Property (SVEP) and has dense glocal spectral subspaces in terms of the spectrum of the generator of T . Likewise, the adjoint H∗ν has trivial spectral subspaces and enjoys the Dunford property. As an application, for the classical Cesàro operator C acting on the Hardy spaces Hp (1 < p < ∞), it follows that the local spectrum of C at any non-zero Hp-function or the spectrum of the restriction of C to any of its nontrivial closed invariant subspaces coincides with the spectrum of C. Finally, we characterize the local spectral properties of subordinated operators arising from hyperbolic semigroups of composition operators acting on Hp (1 < p < ∞), which will depend only on the geometry of the associated Koenigs domain.Ministerio de Ciencia e InnovaciónDepto. de Análisis Matemático y Matemática AplicadaFac. de Ciencias MatemáticasTRUEpu
BaNiO3 Electrocatalysts for Oxygen Evolution Reaction: the Role of Synthetic Methods
No full textBaNiO3 and other Ba-Ni-O related phases are among the most active non-precious electrocatalysts towards the oxygen evolution reaction (OER) in basic media but the relationships between the synthesis conditions and the electrochemical properties have not been thoroughly investigated, which prevents further optimization of the materials performances. In this work, we compare the electrocatalytic activities of hexagonal perovskite BaNiO3 prepared by three different synthesis methods: sol-gel, metal nitrate decomposition and molten salts. We show by combining atomic-scale imaging and spectroscopic techniques how the choice of the synthesis method influences the chemical, morphological and microstructural features of the materials. We especially demonstrate by Energy Electron Loss Spectroscopy and X-Ray Photoelectron Spectroscopy that previously reported electrocatalytic results concerning BaNiO3 prepared in molten salts are actually related to the presence of an unreported nickel hydroxide shell, which ultimately results in enhanced electrocatalytic activity. These results highlight how the synthesis method can strongly influence oxygen electrocatalysis, which paves the way to further surface engineering of other energy materials.Comunidad de MadridEuropean UnionDepto. de Química InorgánicaFac. de Ciencias QuímicasTRUEinpres
Behavioural plasticity in circadian foraging patterns increases resistance of brown trout populations to environmental change
No full textThis study was partly funded by the Spanish Ministry of Science, Innovation and Universities (grant number PID2023-148644OB-I00) and by the Complutense University of Madrid-UCM (grant number PR3/23-30814).Stream-dwelling salmonids in the low-latitude and -altitude margins of their range are particularly threatened by climate change. However, they possess a variety of evolutionary, plastic, and behavioural mechanisms that provide resistance against rapid changes in their environment. Behavioural plasticity can be important under rapid environmental change because it is relatively fast and flexible. In particular, salmonids can exhibit flexible diel activity patterns in response to new environmental conditions, but the consequences of this capability for long-term population persistence in the face of climate change remain unclear. We used an individual-based model to simulate the trajectory of a brown trout population at the warmest edge of its range under three environmental-change scenarios of increasing warming and streamflow reduction. We assessed (1) how simulated trout responded behaviourally to climate change by modifying their circadian foraging patterns, and (2) how much this behavioural plasticity buffered the population-level consequences of environmental change. Our simulations showed that under current conditions trout of different age classes segregated foraging both temporally and spatially. The most consistent response to environmental change was more diurnal feeding in all age classes and under all scenarios, with the strength of this response increasing with the severity of change. In addition, total daily foraging activity increased in all age classes. A second experiment indicated that virtual populations of individuals capable of flexible circadian feeding were more resistant to environmental change than populations restricted to fixed feeding patterns. Thus, our computational experiment suggests that the ability of fish to adaptively select when as well as where to feed, well-documented at the individual level in the empirical literature, could potentially buffer the demographic impacts of long-term environmental change.Ministerio de Ciencia, Innovación y Universidades (España)Universidad Complutense de MadridDepto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu
Long-term WBE monitoring of alcohol, nicotine, and caffeine in two Spanish cities: COVID-19 impacts and beyond
No full textWastewater-based epidemiology (WBE) is a valuable tool for assessing population-level consumption of addictive substances. This study presents long-term WBE monitoring (2021–2025) of alcohol, nicotine, and caffeine in Madrid and Guadalajara (Spain), including the first city-wide spatial analysis in Europe. A total of 192 composite 24-h untreated wastewater
samples were collected from nine wastewater treatment plants: one in Guadalajara and eight in Madrid. Regression models were applied to assess spatial and temporal trends, as well as the impact of key events such as the COVID-19 restrictions, New Year celebrations, and weekends. Key findings show that between 2021 and 2024 alcohol and nicotine use showed a decreasing trend in both cities, while caffeine consumption remained stable with slight increases. In Madrid, average alcohol consumption declined from 27.7 to 16.3 mL/day/person and nicotine by approximately 800 mg/day/1000 person; in Guadalajara, alcohol decreased from 13.1 to 7.7 mL/day/person and nicotine 500 mg/day/1000 person. In December 2023, full city-level estimates from Madrid revealed alcohol consumption between 12.8–18.4 mL/day/person, nicotine 2180–3300 mg/day/1000 person, and caffeine 68.5–134.7 mg/day/person. Notably, alcohol and nicotine reached their highest levels among the New Year periods during the 2022–2023 celebration, the first unrestricted one after the pandemic; levels during this period dropped in the following years. These results highlight temporal and spatial patterns in the consumption of legal substances and suggest shifts in public behavior after COVID-19 and the utility of WBE as a long-term monitoring tool for public health surveillance and planning.Plan Nacional sobre Drogas (Ministerio de Sanidad)Ministerio de Ciencia, Innovación y UniversidadesDepto. de Química AnalíticaFac. de Ciencias QuímicasTRUEpu
Análisis de discurso feminista en la publicidad de las redes sociales: Estudio contrastivo de las estrategias de femvertising en China y España
No full textEste trabajo busca analizar las estrategias de femvertising en el sector de belleza en redes sociales presentadas en las campañas del Día Internacional de la Mujer (8 de marzo) a través de la comparación de campañas publicadas en China (Weibo) y España (Instagram). El objetivo principal es examinar cómo las marcas representan el empoderamiento femenino y la identidad de las mujeres a través de discursos publicitarios adaptados a cada contexto cultural.
A partir del análisis de la recopilación de un corpus de 87 anuncios publicados entre 2022 y 2024 en las dos plataformas, se examinan las estrategias discursivas y visuales vinculadas a la representación del empoderamiento femenino, la diversidad y los estereotipos de género. Los resultados evidencian diferencias significativas entre ambos países. En China, el discurso de empoderamiento tiende a estar ligado al consumo y a la resignificación comercial del 8M como “Día de la Diosa”, mientras que en España se observa un enfoque más simbólico y abstracto, centrado en valores de igualdad y diversidad, aunque también marcado por una lógica de mercado. Ambos contextos reflejan tensiones entre el discurso feminista y su apropiación comercial, manifestando características del postfeminismo y del commodity feminism.This work seeks to analyze femvertising strategies in the beauty sector in social networks presented in the campaigns of International Women's Day (March 8) through the comparison of campaigns
published in China (Weibo) and Spain (Instagram). The main objective is to examine how brands represent the female empowerment and the identity of women through advertising discourses adapted to each cultural context. From the analysis of the compilation of an 87 ads published between 2022 and 2024 on the two platforms, discursive and visual strategies linked to the representation of female empowerment, diversity and gender stereotypes are examined. The results show significant differences between the two countries. In China, empowerment discourse tends to be linked to consumption and commercial resignification of 8M as "goddess day", while in Spain a more symbolic and abstract approach is observed, focused on values of equality and diversity, although also marked by a market logic. Both contexts reflect tensions between feminist discourse and its commercial appropriation, manifesting characteristics of postfeminism and commodity feminism.Depto. de Sociología: Metodología y TeoríaFac. de Ciencias de la InformaciónTRUEsubmitte
Guías museísticos personalizados mediante avatares con Inteligencia Artificial Generativa
No full textTrabajo de Fin de Grado en Ingeniería Informática, Facultad de Informática UCM, Departamento de Ingeniería de Software e Inteligencia Artificial, Curso 2024/2025Este Trabajo de Fin de Grado consiste en el desarrollo de un chatbot estilizado de manera que se comporte como un personaje histórico del siglo XVI en Sudamérica: don Francisco de Arobe. Para ello se utiliza un sistema de Inteligencia Artificial en el que interactúan múltiples modelos, siendo el más importante de ellos un Modelo Grande de Lenguaje. Se ha llevado a cabo en respuesta a la iniciativa del Museo de América. La aplicación se desarrollará para adecuarse al contexto en el que se va a usar: una sala de un museo. Con este objetivo, se prestará especial atención en evitar comportamientos que puedan provocar disonancia con el público.This Bachelor’s Thesis consists of the development of a stylized chatbot designed to behave as a historical 16th-century character in South America: don Francisco de Arobe. For this purpose, an Artificial Intelligence system is used in which multiple models interact, the most important of them being the Large Language Model. It has been carried out in response to an initiative from the Museum of America. The application will be developed to suit the context in which it will be used: a museum hall. With this objective, special attention will be paid to avoiding behaviors that could create dissonance with the public.Depto. de Ingeniería de Software e Inteligencia Artificial (ISIA)Fac. de InformáticaTRUEunpu
