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Improving densification in Al2024 injection moulding parts by trace additions and its ThermoCalc simulations
Get PDFThe main objective of this work is the design of a sustainable aluminium-based feedstock in the form of pellets optimised to obtain aluminium alloy parts with the highest possible densification, for use in an industrial application by manufacturing processes such as Powder Injection Moulding (PIM) and the 3D printing technique Composite Extrusion Modelling (CEM). For the production of aluminium alloy parts from a sustainable feedstock, the PIM process was used, through which the feedstock design was carried out and the optimal debinding and sintering conditions were established. This sustainable feedstock was manufactured by combining 2024 alloy powders with a water-soluble polymer, polyethylene glycol (PEG), and a low-CO2 emitting polymer, cellulose acetate butyrate (CAB). Using ThermoCalc software, the influence of the quantity of the trace element additions in the liquid phase of the 2024 aluminium alloy was analysed. Thanks to the results of these simulations, the optimal trace element percentage was selected to achieve the highest possible densification of the sintered parts. A microstructural characterisation of the tin-added parts was also done to check the densification of the parts, as well as a mechanical characterisation obtaining superior properties to injected parts from aluminium powders with smaller particle size.The authors would like to thank the funding provided for this research by the Regional Government of Madrid (Dir. Gral. Universidades e Investigación) through the project PID2019–106631GB-C43 financed by the Government of Spain and the project S2018/NMT4411 (ADITIMAT-CM) financed by the Government of the Community of Madrid
Heterogeneous Polar Amplification
No full textArctic and Antarctic climate evolution is crucial for understanding global climate dynamics. This study grounds in the framework of Gadea and Gonzalo (2020, 2025) to analyze different distributional characteristics (beyond the average) of polar temperature measurement as time series objects, enabling the definition and robust testing of polar warming, its acceleration, and amplification. Our findings provide a quantitative description of the warming processes affecting the polar regions. The research examines measurements of temperature in the Arctic (1900-2019) and the Antarctic (1960-2022). Key findings include: (i) Clear Arctic warming since 1900 across all quantiles, with more pronounced warming in lower quantiles since 1950. No significant warming was observed in Antarctica in all of the temperature quantiles; (ii) Arctic warming acceleration since 1960, particularly in lower and middle quantiles, with no apparent peak reached yet; (iii) Consistent Arctic amplification is slightly below 2 and stable across analyzed periods. Lower quantiles (corresponding with winter in the higher latitudes) show larger amplification than the mean. Since 1960, amplification has extended to upper quantiles, except the 90th and 95th percentiles; (iv) Analysis of the internal Arctic amplification shows that this is primarily a lower-quantile phenomenon, Arctic amplification is stronger in higher latitude winters and this affects the speed at which the ice in the Arctic is disappearing.
The study’s amplification estimates are lower than some observational studies but align more closely with climate model projections. The paper concludes by comparing these results to the equivalent global temperature trends.The financial support from: Gobierno de Aragón and European Regional Development Fund (ERDF, EU) funds under grant, LMP71-18; Spanish Ministerio de Ciencia e Innovación, Agencia Española de Investigación MCIN/AEI /10.13039/501100011033 and European Regional Development Fund (ERDF, EU) under grants PID2020-114646RB-C44, PID2023-147593NB-I00 and CEX2021-001181 ((María de Maeztu); Spanish Ministerio de Ciencia e Innovación, Agencia Estatal de Investigación MCIN/AEI /10.13039/501100011033 and Unión Europea NextGenerationEU/PRTR, under grant with reference TED2021-129784B-I00.; Comunidad de Madrid under grands grants EPUC3M11 and V PRICIT), is gratefully acknowledged
Universality arising from invertible weighted composition operators
No full textA linear operator U acting boundedly on an infinite-dimensional separable complex Hilbert space H is universal if every linear bounded operator acting on H is similar to a scalar multiple of a restriction of U to one of its invariant subspaces. It turns out that characterizing the lattice of closed invariant subspaces of a universal operator is equivalent to solve the Invariant Subspace Problem for Hilbert spaces. In this paper, we consider invertible weighted hyperbolic composition operators and we prove the universality of the translations by eigenvalues of such operators, acting on Hardy and weighted Bergman spaces. Some consequences for the Banach space case are also discussed.Authors have been partially supported by Project PID2022-137294NB-I00, DGI-FEDER, of the MCYTS. First and third authors have been partially supported by Project E48_23R, D.G. Aragón, Universidad de Zaragoza, Spain. Third author has also been partially supported by XXXV Grants for Postdoctoral Studies, by Ramón Areces Foundation
Mobilization capacity and violence against local leaders: Anticlerical violence during the Spanish Civil War
No full textAguilar, P., Cuesta, F. de la, Sánchez-Cuenca, I. & Villamil, F. (2025). Mobilization Capacity and Violence Against Local Leaders: Anticlerical Violence During the Spanish Civil War. Comparative Political Studies, 58(7), 1319-1351. https://doi.org/10.1177/00104140241269894Research on civilian victimization usually treats all civilians as a unitary group. But not all civilians are the same, nor are they killed for the same reasons. This study highlights a form of wartime civilian victimization that is little understood, even if pervasive across conflicts: violence against local leaders. We argue that this category of civilians are pre-emptively targeted because of their potential to mobilize support. Local leaders with greater mobilization capacity are more likely to be killed. We test this argument using original data on clergy killings during the Spanish Civil War. Results show that clerics were more likely to be killed in municipalities where their capacity for mobilizing people against the Republic was higher, making themselves a potential threat to local armed actors. This study highlights the need to disaggregate the category of civilians, which has suffered from conceptual and empirical overaggregation.We acknowledge financial support from the Spanish Ministry of the Presidency (projects 191-MD-2021 and 102-MD-2022)
Explainable Earth Surface Forecasting Under Extreme Events
No full textWith climate change-related extreme events on the rise, high-dimensional Earth observation data present a unique opportunity for forecasting and understanding impacts on ecosystems. This is, however, impeded by the complexity of processing, visualizing, modeling, and explaining this data. We train a convolutional long short-term memory-based architecture on the novel DeepExtremeCubes data set to showcase how this challenge can be met. DeepExtremeCubes includes around 40,000 long-term Sentinel-2 minicubes (January 2016–October 2022) worldwide, along with labeled extreme events, meteorological data, vegetation land cover, and a topography map, sampled from locations affected by extreme climate events and surrounding areas. When predicting future reflectances and vegetation impacts through the kernel normalized difference vegetation index, the model achieved an R2 score of 0.9055 in the test set. Explainable artificial intelligence was used to analyze the model's predictions during the October 2020 Central South America compound heatwave and drought event. We chose the same area exactly 1 year before the event as a counterfactual, finding that the average temperature and surface pressure are generally the most important predictors. In contrast, minimum evaporation anomalies play a leading role during the event. We also found the anomalies of the reflectances in the timestep before the extreme event to be critical predictors of its impact on vegetation. The code to replicate all experiments and figures in this paper is publicly available at https://github.com/DeepExtremes/txyXAI.This work was supported by the ESA AI4Science project Multi-Hazards, Compounds and Cascade events: DeepExtremes, 2022-2024; the European Union's Horizon 2020 research and innovation project XAIDA: Extreme Events Artificial Intelligence for Detection and Attribution, 2021-2024 (Grant agreement No 101003469); and the European Union's Horizon 2022 project ELIAS: European Lighthouse of AI for Sustainability, 2023-2027 (Grant agreement No. 101120237). The authors acknowledge the support from the computer resources provided by Artemisa (funded by the European Union ERDF and Comunitat Valenciana), as well as the technical support provided by the Instituto de Física Corpuscular, IFIC (CSIC-UV)
Simulación del entorno Smallville con agentes BDI
No full textEste Trabajo Fin de Grado consiste en el diseño y desarrollo de una simulación multiagente basada en el paradigma BDI (Beliefs, Desires, Intentions) utilizando la plataforma
GAMA y su lenguaje de modelado GAML. La simulación se inspira en el entorno "Smallville", un referente académico en inteligencia artificial para la modelización del
comportamiento humano, pero ha sido adaptada para representar un entorno más reducido y cotidiano: un piso compartido por cuatro estudiantes universitarios.
Cada uno de los estudiantes —Julio, Mark, Dani y Antonio— está representado por un agente autónomo BDI, capaz de tomar decisiones en función de sus creencias, deseos
e intenciones. Estos agentes poseen emociones (felicidad, tristeza, apatía y enfado), personalidad, y un conjunto dinámico de reglas que determinan sus acciones a lo largo del día (como ir al baño, estudiar, cocinar, conversar o ver la televisión). El entorno está modelado espacialmente, incluyendo estancias comunes como cocina, comedor, dormitorios y baño, con objetos interactivos (sofá, ducha, encimera, frigorífico, etc.).
El modelo incorpora una gestión del tiempo en ciclos que simulan horas y días, permitiendo observar la evolución del comportamiento de los agentes y sus emociones en
función de la hora y las interacciones sociales. La arquitectura emocional influye directamente en el comportamiento, modulando las ganas de hablar y participar en conversaciones. Además, se ha implementado un sistema de comunicación mediante protocolos FIPA, lo que permite la emisión y respuesta a mensajes como saludos, propuestas, peticiones o intercambio de información.
El objetivo principal del proyecto ha sido demostrar cómo es posible simular de forma realista comportamientos complejos en un entorno doméstico mediante agentes BDI,
y cómo las emociones y las interacciones sociales pueden influir en la dinámica del grupo. Este tipo de simulaciones pueden tener aplicaciones en estudios de comportamiento
humano, desarrollo de asistentes virtuales, o entornos de entrenamiento en IA. La plataforma GAMA ha resultado especialmente adecuada para este tipo de modelado debido a
su versatilidad, herramientas visuales y compatibilidad con arquitecturas cognitivas.Grado en Ingeniería Informátic
Collective phases and long-term dynamics in a fish school model with burst-and-coast swimming
No full textIntermittent and asynchronous burst-and-coast swimming is widely adopted by various species of fish as an energy-efficient mode of locomotion. This swimming mode significantly influences how fish integrate information and make decisions in a social context. Here, we introduce a simplified fish school model in which individuals have an asynchronous burst-and-coast swimming mode and selectively interact only with one or two neighbours that exert the largest influence on their behaviour over a limited spatial range. The interactions consist of a fish that is attracted to and aligned with these neighbours. We show that, by adjusting the interactions between individuals above a sufficiently high level, depending on the relative strength of attraction and alignment, the model can produce a cohesive fish school that replicates the main collective phases observed in nature: schooling, milling and swarming when each individual interacts with only one neighbour; and schooling and swarming when each individual interacts with two neighbours. Moreover, the model showed that these patterns can be maintained over long simulations. However, with the exception of swarming, these patterns do not persist indefinitely, and fish lose cohesion and progressively disperse. We further identified the mechanisms that lead to group dispersion.G.T., R.E., S.S., and C.S. were supported by Agence Nationale de la Recherche (ANR-20-CE45 0006-1). WW was funded by a grant from the China Scholarship Council (CSC No. 201906040126). ZH was supported by the National Natural Science Foundation of China (Grant No. 62176022)
Analysis of the disinformation campaign in Brazil's 2022 Elections
No full textLa desinformación durante las elecciones brasileñas de 2022 alcanzó su momento de mayor intensidad el 8 de enero de 2023, coincidiendo con un intento de asalto a las instituciones estatales. Previamente, una ola de informaciones falsas y teorías conspirativas con el claro objetivo de deslegitimar el sistema electoral y atacar a los principales candidatos fue el escenario digital que marcó las elecciones presidenciales. Este estudio examina los bulos relacionados con los comicios presidenciales de 2022 a través de las verificaciones realizadas por dos de las principales organizaciones de verificación de datos del país: Agência Lupa y Aos Fatos. La muestra comprende 219 piezas de verificación publicadas entre el 29 de agosto y el 31 de octubre de 2022. Los resultados revelan una campaña electoral marcada por bulos en formato audiovisual viralizados especialmente Facebook y WhatsApp, destacando un mayor flujo desinformador en la segunda vuelta. Asimismo, predominan los contenidos engañosos sobre los procesos de votación y el fraude electoral. Por su parte, los principales objetivos desinformadores fueron los candidatos presidenciales Lula da Silva y Jair Bolsonaro.Disinformation during the 2022 Brazilian elections peaked on January 8, 2023, coinciding with an attempted assault on key state institutions. Previously, a wave of false information and conspiracy theories with the clear objective of delegitimizing the electoral system and attacking the main candidates was the scenario that distinguished the presidential elections. This study examines hoaxes related to the 2022 Brazilian elections through verifications conducted by two leading fact-checking organizations: Agência
Lupa and Aos Fatos. The sample comprises 219 pieces of verification published between August 29 and October 31, 2022. The results reveal an electoral campaign characterised by hoaxes in viral audiovisual format, particularly spread on Facebook and WhatsApp, with a higher flow of disinformation in the second round. Likewise, deceptive content about voting processes and electoral fraud predominates. Additionally, the main targets of false narratives were the presidential candidates Lula da Silva and Jair Bolsonaro.Este artículo ha sido revisado en inglés por Harvey Holtom a quien agradecemos su trabajo. Fuentes de financiación: Este trabajo forma parte del proyecto IBERIFIER Plus, cofinanciado por la Comisión Europea bajo la convocatoria DIGITAL-2023-DEPLOY-04, European Digital Media observatory (EDMO) – National and multinational hubs, Referencia: IBERIFIER Plus - 10115851
Hybrid mortars activated with alternative steel-compatible salts: impact on chloride diffusion and durability
No full textEco-friendly mortars have been manufactured with hybrid binders made of blast furnace slag and a reduced amount of clinker. The objective is to explore new formulations suitable for reinforced structures. Previous studies are mainly focused on activation with sulfates, a salt that is corrosive to reinforcing steel. Sodium nitrate and sodium carbonate, easily implementable in construction, have been used as activators in two different concentrations that involve similar Na content. A Type II PC mortar is used as reference. The dimensional stability of the mortars during curing (at 99% RH) and subsequent drying at 40% RH, has been evaluated, as well as their porosity and mechanical properties. Böhme tests revealed that studied hybrid binders have lower wear resistance than PC mortar. Activation with Na2CO3 allows the obtention of mortars with reduced porosity and good compression resistance, but generates microcracking that favors chloride diffusion. Activation with nitrates favors precipitation of AFm phases identified through differential thermal analysis. Nitrates in moderate amounts (4% w/w) allow manufacturing hybrid mortars with good resistance to chloride penetration and reasonably good mechanical properties. Hence, this binder can be a promising option for reinforced structures. Higher amounts of nitrates (8%) for activation give rise to more porous mortars.This study was funded by PID2021-125810OB-C22 project “Development of eco-efficient cementitious materials with low-impact and high durability” (EcoCeMat), financed by MCIN/AEI/10.13039/501100011033/ and FEDER “Una manera de hacer Europa”
La extensión del maltrato psicológico como causa de desheredación. Comentario a la STS 802/2024, de 5 de junio (JUR 2024, 179177)
No full text[ES] En esta sentencia el Tribunal Supremo, continuando con la doctrina que ha ido conformando a partir de la STS 258/2014, de 3 junio, perfila lo que debe entenderse como maltrato psicológico y que entra dentro del maltrato de obra como causa de desheredación del artículo 853,2º CC. Para ello, manifiesta que la ruptura del vínculo afectivo paterno-filial producido a raíz de la separación judicial de los progenitores, siendo la hija menor de edad, sólo puede ser imputable al padre, que la abandonó y no tuvo ningún tipo de relación con la hija durante casi 30 años. La enfermedad terminal del padre, dada a conocer a la hija unos meses antes de la muerte, sin que aquella fuera a visitarlo ni se preocupara por su padre no puede ser objeto de reproche ni puede causar sufrimiento o daño psicológico al padre. En consecuencia, no puede decirse que exista maltrato psicológico como causa de desheredación del artículo 853,2º CC.[EN] In this judgment, the Supreme Court, continuing with the doctrine that has been formed from STS 258/2014, of 3 June, outlines what must be understood as psychological abuse and which fa/Is within the scope of maltreatment at work as a cause of disinheritance of article 853,20 CC. In this respect, it states that the breakdown of the relationship between parents and children fol/owing the legal separation of the parents, since the child is under age, can only be attributed to the father, who abandoned her and had no relationship whatsoever with the éhild for almost 30 years. The terminal il/ness of the father, when the daughter is informed a few months befare death, without her going to visit him or worrying about her father, cannot be reproached and may cause psycho/ogica/ suffering or damage to the father. Consequently, it cannot be said that psycho/ogical abuse is a cause of disinheritance under article 853.2 of the CC