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Estrategias de control robusto para procesos de soldadura po arco eléctrico
Get PDF197 p.Welding, a fundamental process in modern manufacturing, joins metal components by melting them and allowing them to solidify, often with a filler material. Its widespread use is evident in the fact that over half of manufactured products are estimated to contain welded joints. However, achieving precise control over the welding process to ensure desired mechanical properties, such as strong, distortion-free joints with minimal residual stress, remains a significant challenge. Despite welding's importance, the application of sophisticated control techniques has not kept pace with other manufacturing domains. This research aims to bridge this gap by developing models that link controllable parameters (power and travel speed) to temperature, and by designing control systems to maintain the process within specified parameters. This study investigates two distinct welding applications. First, a long-duration welding process, common in large structure fabrication, is examined. A simplified 1D model serves as the basis for a decentralized control system that manipulates power and travel speed to achieve a target cooling curve. Second, the complexities of additive manufacturing are addressed. The layer-by-layer nature of this process and the associated heat accumulation demand a more advanced control strategy. A multivariable controller, designed using sequential Quantitative Feedback Theory (QFT), regulates the surface temperature profile by adjusting power and travel speed, with particular emphasis on the challenges posed by direction changes during layer creatio
Jeffrey A. Easton, Municipal Freedmen and Intergenerational Social Mobility in Roman Italy, Brill Studies in Greek and Roman Epigraphy, vol. 21, 2024, 369 pp., ISBN 978-90-04-68634-2.
Get PDFContaminación acústica submarina: análisis de la normativa europea y estatal vigente y las estrategias de futuro
No full textEl trabajo analiza la problemática de contaminación acústica submarina, abordando su origen, impacto y regulación. Se estudian las principales fuentes de ruido en el medio marino, entre ellas el tráfico marítimo, y se exponen sus efectos negativos en la fauna marina, que incluyen alteraciones en el comportamiento, interferencias en la comunicación y daños fisiológicos.
Asimismo, examina la legislación actual a escala internacional, europea y estatal, evaluando su evolución y eficacia en la reducción del impacto del ruido submarino.
Para determinar la efectividad de la normativa europea actual, se identifican deficiencias en la aplicación de estas regulaciones y se mencionan mejoras recomendadas por expertos para fortalecer la protección de los ecosistemas marinos, esto es, se compara con la evidencia científica más reciente sobre los efectos del ruido submarino. A través de esta comparación, se evalúa si la legislación vigente responde adecuadamente a los conocimientos actuales o si es necesario implementar medidas adicionales. Este análisis permite valorar en qué medida la normativa es determinante en la reducción del impacto acústico marino y qué aspectos podrían reforzarse para mejorar la protección de la biodiversidad marina
Ground Fault Location Method for Catenaries of DC Railway Systems
No full textPaper 2024-IDC-0898.R2, presented at the 2023 IEEE International Conference on Environment and Electrical Engineering and 2023 IEEE Industrial and Commercial Power Systems Europe, Madrid, Spain, Jun. 06–09,The utilization of Direct Current (DC) railway systems is increasingly prevalent, as it constitutes the majority of
urban tram power supply systems. Despite their high efficiency, the risk of ground faults is ever-present due to environmental issues and aging of the catenaries. These faults can interrupt the service for hours until repaired, requiring quick repair. To address this issue, this paper introduces a ground fault location method for catenaries in DC railway systems, based on the measurement of the DC voltage and ground current at each DC Traction Substation (TS). Then, the normalized ground currents relative to the
overall fault current are compared with a model-based data pool, enabling the method to locate the fault along the protected cate-
nary. The method’s validity has been confirmed through numerous simulations and experimental tests. Initially, simulations were
conducted on a three-TS DC railway model in Matlab-Simulink, yielding promising results. Subsequently, experimental laboratory
tests were performed using uncontrolled rectifiers in the TS, also producing encouraging results. Finally, the suitability of the fault
location method was verified using Hardware-In-the-Loop (HIL) tests emulating controlled rectifiers.This work was supported in part by the Basque Government and GISEL research group (Universidad del País Vasco) under Grant OT1522-22 and in part by the European Union-Next Generation EU under Grant “INVESTIGO.
Voting record of the UNGA on “Elimination of unilateral and extraterritorial coercive economic measures as a means of political and economic compulsion
No full textCrystal structure, magnetic and magnetocaloric properties of the new orthorhombic Y3Co2-type Gd3Co1+xNi1−x solid solution
No full textThis work reports the existence of the new rare-earth intermetallic compound Gd3Co1+xNi1-x (with x = 0.1, 0.2, 0.3, and 0.4) and the investigation of its crystallographic, magnetic, and magnetocaloric properties. Gd3Co1+xNi1-x is a novel solid solution phase that crystallizes in the orthorhombic Y3Co2-type structure [oP20, Pnmm (No. 58)]. It constitutes the first representative of a compound crystallizing in this structural prototype. The research also includes an analysis of the critical behavior associated with the second-order phase transition from a paramagnetic to a ferromagnetic state (PM-FM) detected in the compound. This analysis indicates that short-range order isotropic magnetic interactions are present, consistent with the 3D Heisenberg model. Increasing the Co content leads to a higher Curie temperature (TC), thus, shifting the peak of the magnetic entropy change, while maintaining the overall physical properties. This demonstrates the potential of tuning the working temperature region by modifying the Co/Ni concentration without negatively affecting the magnetocaloric properties. For μ_0 ∆H=5 T, the magnetic entropy change peaks range between 7.81 and 8.40 J kg-1K-1, while the refrigerant capacity values are around 600 J kg-1. These results place this family among the top performing ones in their working temperature region. The scaling relations and the universal curve confirm the second-order nature of the phase transition and validate the calculated critical exponents.Departamento de Educación del Gobierno Vasco (project IT1430-22
Root growth in mechanically heterogeneous substrates
No full text212 p.Roots adapt to changes in soil mechanical resistance through physiological, developmental, and morphological adjustments. These responses are primarily studied in the context of homogeneous mechanical resistance. Traits such as increased root diameter, which increases bending stiffness, and a sharper root tip are generally recognized as helping the root to penetrate impeding soil. Mucilage and border cells that detach from the root cap also reduce friction, while root hairs anchor the root into the soil.Recent research has examined how roots respond to physical barriers, showing that plants can sense mechanical signals, linking the presence of obstacles to thigmotropism, gravitropism, and possibly proprioception. However, significant gaps remain in understanding how roots bypass individual obstacles and how root systems respond to complex soil heterogeneity. Experimental substrates like gels or milled and sieved soils simplify growth conditions but eliminate heterogeneity at the root scale. Growing roots against a hard plate, penetrable or not, is also very remote from natural soil heterogeneity which can consist of stones or small particles aggregating into clusters of various size,shape and mechanical strength, separated by cracks and pores.This thesis investigates the effect of substrate physical heterogeneity on root growth. The hypothesis tested is that soil heterogeneities can be represented by two variables: the spatial scale of heterogeneity (e.g., obstacle size) and the mechanical strength of the obstacle. Different substrates were designed to study plant root responses to these factors.Chapter 2 examines large, rigid heterogeneities at fixed locations, focusing on conditions under which maize roots maintain a vertical trajectory. The growth substrate consisted of 3D-printed circular obstacles embedded in agarose gel. A high-throughput root phenotyping platform captured time-lapse images, and image analysis evaluated growth trajectories. Results showed stable vertical and oblique root trajectories, influenced by obstacle size. Intermediate-sized obstacles caused unstable trajectories that changed over time. The conditions for root trajectory changes were formalized, linking detachment angle from an obstacle to root curvature from gravitropism. The root's ability to curve and respond to gravitropic signals may constrain path selection.Chapter 3 explores large but soft, penetrable obstacles. Agarose cylinders of varying sizes and strengths were used as analogs for soil aggregates, which roots can either penetrate or bypass. The mechanical properties of the system were well-defined, with agarose characterized and mechanical stress determined from cylinder contact geometry. A live imaging platform was developed to capture the root trajectory over time, and a custom image analysis pipeline created a comprehensive database of root responses. Conditions for root penetration and for maintaining a straight trajectory were linked to the strength and stiffness of both the gel and root, as well as the geometry of the pores.Chapter 4 examines root growth responses to small, soft obstacles that roots can displace or penetrate. Fabricating cylinders the size of root diameters and arranging them in a 2D lattice to control growth conditions was challenging. However, microfabrication techniques were successfully applied to create systems using PEGDA-gel cylinders photopolymerized into microfluidic chambers, enabling long-term plant cultivation for root studies.In conclusion, this thesis demonstrates that root responses to soil heterogeneity depend on the nature of physical barriers. These responses can be predicted using mechanical principles. While derived from simplified systems, the results capture key soil structure aspects and the findings provide valuable insights for optimizing soil management to improve agricultural productivity by predicting root responses to physical obstacles
Towards scalable semi-supervised learning on graphs
No full text134 p.Graph-based semi-supervised learning (GSSL) has attracted considerable attentiondue to its ability to leverage both labeled and unlabeled data to improveclassification performance. This thesis addresses the limitations of traditional GSSLmethods, such as reliance on predefined graphs, computational inefficiency withlarge datasets, treating data equally, and insufficient handling of unlabeled data, byproposing a unified and scalable framework.Recent advancements in GSSL have primarily focused on predefined graphstructures, which often do not accurately represent the data topology, and strugglewith scalability issues. To overcome these challenges, this research introducesseveral innovative approaches, including anchor-based graph construction, adaptivesample weighting, and dynamic self-training, specifically designed for large-scaledatasets.The Joint Graph and Reduced Flexible Manifold Embedding (SGRFME) algorithmintegrates anchor graph computation into the learning model. This approach notonly scales efficiently to large databases but also improves the accuracy of labelpredictions for test samples through linear transformations. Experimental results ondatasets such as NORB, RCV1, and Covtype demonstrate the method'seffectiveness and scalability.Addressing graph topology imbalance, the Weighted Simultaneous GraphConstruction and Reduced Flexible Manifold Embedding (W-SGRFME) algorithmextends the concept of graph topology imbalance to large datasets and incorporatescomputed weights of labeled samples into the model. The fusion of labels andfeatures of anchors allows for adaptive graph construction, resulting in superiorperformance on large datasets.A scalable and inductive semi-supervised classifier with sample weighting based ongraph topology, called the Weighted Joint Graph Construction and ReducedFlexible Manifold Embedding (W-JGRFME), employs calculated weights oflabeled samples for label-matching, leading to a unified and scalable model thatsimultaneously labels unlabeled data and constructs an adaptive anchor graph.Experimental results on extensive datasets, including MNIST, validate the method'srobustness and superiority.A unified framework for inductive and scalable GSSL using adaptive sampleweighting, termed Adaptive Weighted Simultaneous Graph Construction andReduced Flexible Manifold Embedding (AW-SGRFME), assigns adaptive weightsto labeled samples based on their estimated labels and constructs an anchor-toanchoraffinity graph by incorporating both feature and label information. Theefficacy of this method is illustrated through experiments on large-scale datasets.Lastly, the Self-training Simultaneous Graph Construction and Reduced FlexibleManifold Embedding (SSGRFME) framework, tailored for very large datasets,utilizes pseudo-labeling to enhance the model's accuracy by incorporatingconfidently predicted labels of random batches of unlabeled samples into thetraining set. The anchor-to-anchor affinity graphs facilitate robust learning, asdemonstrated by comprehensive experimentation across diverse large datasets.Overall, this thesis makes significant contributions to the field of GSSL byintroducing automatic graph consrtuction, weighted labeled samples, and selftrainingmethods that effectively address the challenges of large-scale semisupervisedlearning. These innovative approaches not only enhance the performanceof GSSL models but also extend their applicability across various domains, providinga robust foundation for future research. The main contributions of the thesis areoutlined below.(1) Proposes the SGRFME model, which handles large-scale datasets using anchorpoints. SGRFME jointly predicts labels, constructs the anchor affinity matrix, andestimates a projection matrix for test samples.(2) SGRFME emphasizes the integration of graph construction and label estimationinto a unified objective function.(3) W-SGRFME focuses on extending graph topology imbalance to large datasetsand integrating this concept into a scalable semi-supervised model with regularization.(4) Proposes the W-JGRFME model, addressing topological imbalance throughweighted labeled nodes with Nuclear norm Regularization.(5) Introduces the AW-SGRFME method, which uses adaptive weights for labelednodes based on dynamic class prediction.(6) Proposes a dynamic self-training approach for GSSL, integrating graphconstruction and label propagation
Reconfiguraciones de la identidad trans* en territorios de la espera
No full textRegional migration policies have led to the formation of what Musset calls waiting territories, with Tenosique in southern Mexico being a notable example. Waiting should not be understood as a passive space-time. In this paper, I analyze what takes place within this waiting territory during the migratory experience of Nikki, originally from Honduras, who arrived in 2018 with her mother seeking international protection. Bureaucratic measures of border externalization interrupted their transit and caused them to wait several months at La 72, a migrant shelter, between 2018 and 2019. Nikki began her migration with a masculine identity, although she had long desired a feminine identity. Through an affective ethnography and other qualitative techniques, I explore the reflective and material processes related to Nikki's desired feminine identity as a result of her experience in a waiting territory. The aim is to deepen the understanding of social relations and intersubjectivity woven into the time-space of waiting.; Las políticas migratorias de la región han propiciado que en México se produzcan lo que Musset llama territorios de la espera; Tenosique, en el sur de México, es uno de ellos. La espera no es, sin embargo, un espacio-tiempo sin acción. En este texto analizo lo que sucede en ese territorio de la espera en el proceso migrante de Nikki, originaria de Honduras, y que llegó en 2018 con su madre solicitando protección internacional. Las medidas burocráticas de externalización de fronteras interrumpieron su tránsito y las hicieron esperar varios meses en La 72, un albergue para migrantes, entre 2018 y 2019. Nikki inició su migración en una identidad masculina, aunque tenía tiempo deseando una identidad femenina. A través de una etnografía afectiva y otras técnicas cualitativas, exploro los procesos reflexivos y materiales relacionados con la identidad femenina deseada por Nikki, como resultado de su experiencia en el territorio de la espera. Con ello, se busca ampliar los entendimientos de las relaciones sociales y la intersubjetividad que se teje en el tiempo-espacio de la espera
¿Cómo lograr la representación paritaria? Un repaso a la legislación de cuotas de género en la España multinivel
Get PDFCon el objetivo de incrementar la presencia de mujeres en los órganos representativos, en verano de 2024 el Congreso de los Diputados aprobaba una nueva regulación de las cuotas legales que suponía un cambio de modelo. Una modificación de la ley de 2007 que supondrá una mayor limitación de la acción de las fuerzas políticas a la hora de elaborar sus candidaturas a nivel estatal y subestatal. En este artículo analizaremos la trayectoria sobre el debate y la aprobación de las cuotas en España. En este sentido, pondremos el foco sobre la nueva regulación, trataremos de desgranar los principales ejes del debate y los cambios más relevantes introducidos por el legislador. Asimismo, analizaremos el impacto de la nueva regulación en el reparto competencial y en la efectividad para favorecer la presencia de las mujeres en los órganos de representación.With the aim of increasing the presence of women in representative bodies, in the summer of 2024, the Congress of Deputies approved a new regulation of legal quotas, which meant a change in the model. A modification of the 2007 law that will mean a greater limitation of the action of political forces when it comes to drawing up their candidacies at state and sub-state level. In this article we will analyse the history of the debate and approval of quotas in Spain. In this regard, we will focus on the new regulation, and we will try to unravel the main axes of the debate and the most relevant changes introduced by the legislator. We will also analyse the impact of the new regulation on the distribution of powers and on the effectiveness in favouring the presence of women in representative bodies.Grupo de Investigación Gobernanza Multinivel (IT1377-22)