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Optical and radio characterization of continuing current lightning with ASIM, GLM and ELF sensors
No full textLightning with continuing current is a special type of cloud-to-ground flash that can damage electrical systems and cause forest fires, with implications to air quality. Therefore, their precise characterization and early detection are crucial. Here we use a combination of space-based (Atmosphere–Space Interaction Monitor and Geostationary Lightning Mapper) and ground-based (Earth Networks Total Lightning Network and Extreme Low Frequency magnetic field antenna) instruments to systematically identify continuing current lightning between June 1, 2018 and December 31, 2021 in the Contiguous United States. Matched flashes are analyzed using two approaches. In the first, we classify the flashes according to the approximate models of Fairman and Bitzer (2022) as either having continuing current or not. In the second approach, we classify cloud-to-ground flashes reported by the Earth Networks Total Lightning Network using ¿B, a sensitive magnitude derived from Extreme Low Frequency magnetic signals. ¿B quantifies the difference in the average magnetic field signal during the 20 ms before and after the return stroke. A threshold of 0.15 pT was established based on simultaneous observations of a continuing current flash on April 22, 2017, recorded by an Extreme Low Frequency magnetic antenna in Cabo Verde and the Huntsville, Alabama Marx Meter Array. Significant differences were observed in the dual-wavelength (337.0 nm and 777.4 nm) light curves recorded by the Atmosphere–Space Interaction Monitor for flashes with and without continuing current, suggesting its potential for identifying this type of lightning based on spectral emission.This work was supported by the Spanish Ministry of Science and Innovation under project PID2022-136348NB-C31 and the FEDER programme. PACF acknowledges a PhD research contract through the project PID2022-136348-C31. FJPI acknowledges the sponsorship provided by a fellowship (LCF/BQ/PI22/11910026) from the La Caixa Foundation (ID 100010434). In addition, FJPI acknowledges the fellowship RYC2022-035821-I, funded by MCIN/AEI/10.13039/501100011033 and FSE+. Additionally, FJPI, FJGV and PACF acknowledge support from the Severo Ochoa grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033. ASIM is a mission of the European Space Agency (ESA) and is funded by the European Space Agency and by national grants of Denmark, Norway and Spain. The UPC work was supported by research grants from the Spanish Ministry (MCIN/AEI/10.13039/501100011033) PID2019-109269RB-C42, PID2022-136348NB-C32, and EQC2021-006957-P.Peer ReviewedPostprint (published version
NON-COMMUTATIVE ALGEBRA ( Examen Final, 1er Quadrimestre )
No full textExamen Final 1er Quadrimestre2025/20261r quadrimestr
Design of Ni-promoted Ca2Fe2O5/modified ceria as oxygen carrier for fast and carbon-resistant chemical-looping steam methane reforming
No full textChemical looping steam methane reforming enables the production of high-purity syngas and hydrogen while eliminating the energy-intensive downstream separation steps typically required by conventional technologies. Ca2Fe2O5 is a promising oxygen carrier thanks to its high redox stability and low equilibrium pO2. However, its practical application is hindered by sluggish reduction kinetics. Here, we have overcome this limitation by preparing nickel-promoted composite oxygen carriers (OC) through the physical mixing of Ca2Fe2O5 and modified CeO2. The selective deposition of Ni on the surface of the CeO2-based phase significantly increases the OC reduction rate, outperforming samples in which Ni is in close contact with Ca2Fe2O5 (either on the surface or within the lattice). SiO2 modified ceria was found to be more effective than CeO2-Al2O3 and Ce0.8Zr0.2O2 in promoting the microstructural stability of CeO2 within the composite, ensuring consistent performance over multiple redox cycles. The co-presence of Ca2Fe2O5 and the catalyst in the same reactive bed effectively limits carbon formation at a low OC conversion degree. In situ synchrotron X-ray diffraction and isothermal packed-bed tests revealed a gas-mediated synergistic mechanism whereby carbon deposition was inhibited by H2O and CO2 generated locally from the reduction of Ca2Fe2O5. This led to fast oxygen exchange and stable syngas production. After 50 reaction cycles, the composite OC produced 13.0¿mmol/g of syngas in the reduction step with 88¿% CH4 conversion, and 6.8¿mmol/g of H2 in the water splitting step with >¿99¿% purity, demonstrating the potential of this OC design strategy.Postprint (published version
Endovascular repair of aortic dissection with a bioresorbable patch: Computational and experimental study
No full textThis study introduces an experimentally-calibrated finite-element framework to predict the endovascular sealing performance of a bioresorbable patch for aortic dissection repair. The patch–aortic wall interaction was modeled using an adhesion-enabled contact formulation, with parameters derived from a custom dye-penetration test to replicate in-vivo tissue adhesion. A parametric analysis assessed the impact of tear size (10–20 mm), tear morphology (round vs. circumferential ellipse), and deployment angle (5º–20º) on patch sealing efficiency, wall compliance, and local stress distribution under physiological loading. Tear geometry was identified as the dominant determinant of sealing: large round tears reduced effective apposition, while circumferential elliptical tears promoted full wall coupling at lower deployment forces. Increasing deployment angle raised insertion forces and impaired circumferential contact. Importantly, pulsatile hemodynamic loading demonstrated that the patch preserved native wall compliance without inducing adverse stress concentrations. By integrating experimental calibration with computational modeling, this framework offers a quantitative tool to evaluate anatomical and procedural factors influencing endovascular sealing. These insights may support the design optimization and clinical translation of resorbable patch-based strategies for aortic dissection repair.The authors acknowledge financial support from the Spanish Ministry of Science and Innovation CPP2021-008546 and PID2021-122518OB- I00 - "MCIN/AEI/10.13039/501100011033/ y por FEDER Una manera de hacer Europa", La Marató - 202332-30, and EIC Accelerator, Horizon Europe - 190192260.Postprint (published version
Lamas orientables
No full textVídeos docents de l'assignatura Representació Arquitectònica IV, impartida per Isidro Navarro, PDI de l'ETSABVídeos docentes de la asignatura Representación Arquitectónica IV, impartida por Isidro Navarro, PDI de la ETSA
Radio wave propagation through a characterized CO2 plasma flow
No full textThe high levels of ionization of the plasma layer created around a spacecraft during the reentry in planetary atmospheres can cause disruption of the communications, leading to a radio blackout phenomenon. The entry, descending and landing phase of a Mars mission includes degradation and complete loss of the signal for a few minutes. This work, as part of the Horizon 2020 Magnetohydrodynamics Enhanced Entry System for Space Transportation (MEESST) project, presents experimental measurements of radio signal propagation for the first time through a stagnant flow of a CO2 plasma, representative of Mars entry flows. The measurements are conducted at the VKI plasma wind tunnel, the Plasmatron facility, using conical horn antennas at the Ka-band, transmitting inside an optimally designed probe. The probe designed at VKI and its characterization at the UPC anechoic chamber are detailed. The temperature of the plasma flow is measured by means of optical emission spectroscopy, to estimate the plasma frequency and to correlate it with the experimental signal propagation results. The measurements at the plasma wind tunnel show that the signal propagates almost undisturbed for low electric powers (and plasma frequencies), being its magnitude attenuated and its polarization rotated at higher electric powers, when the electron number densities are higher.Diana Luís research is funded by a doctoral fellowship (2021.04930.BD) granted by Fundação para a Ciência e Tecnologia (FCT Portugal). The MEESST project is funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 899298. Prof. Adriano Camps research is funded by project GENESIS (PID 2021-126436OB-C21) sponsored by MCIN/AEI/10.13039/5011000H033/ and EU ERDF “A way to do Europe!”.Peer ReviewedPostprint (published version
Aplicació d’intel·ligència artificial en el control de qualitat visual de peces industrials
No full textAquest Treball de Fi de Grau presenta un estudi de viabilitat per a l’automatització de la inspecció visual de components d’automoció. El problema abordat és la dependència actual d’un procés d’inspecció manual, de caràcter subjectiu, que genera un coll d’ampolla de 21 segons per peça dins la línia de producció. L’objectiu principal del treball és avaluar el potencial de les tècniques d’Intel·ligència Artificial per a l’optimització d’aquest procés de control de qualitat. La metodologia proposada es basa en l’ús d’òptica de deflectometria per ressaltar defectes topogràfics en superfícies reflectants, combinada amb una arquitectura de xarxes neuronals profundes en cascada. El sistema implementa un primer model destinat a la localització automàtica de la regió d’interès de la peça i un segon model orientat a la detecció i classificació de defectes superficials, com ara pics de vernís, cràters i pell de taronja. Els resultats obtinguts amb el prototip desenvolupat en entorn local mostren una elevada precisió en la detecció de la peça (99 %) i una capacitat inicial de detecció dels defectes superficials, amb un temps total de processament de 50,9 mil·lisegons (ms). Aquest rendiment permet assolir una capacitat d’inspecció propera a les 20 imatges per segon, compatible amb els requisits temporals d’un entorn industrial. Finalment, l’anàlisi econòmica realitzada indica que la solució proposada presenta un alt potencial de rendibilitat, amb un període de retorn de la inversió estimat en cinc mesos. En conjunt, els resultats obtinguts validen la viabilitat tècnica del sistema com a prova de concepte i estableixen una base sòlida per a futures millores i una possible industrialització
A new methodology for ultra-fast and accurate statistical EMT analysis in electric power-systems
No full textThis paper introduces Quadrature Mirror Filter Electromagnetic Transient (QMF-EMT) methodology as a novel, precise, and ultra-fast method for statistical studies (SS) of EMTs in electrical networks. Building on a previously proposed approach for real-time EMT simulation, QMF-EMT incorporates nonlinear elements such as surge arresters, sequential switching operations, and a statistical switching model. The method is highly parallelizable and achieves superior accuracy and computational speed compared to conventional time-domain (TD) and frequency-domain (FD) techniques. The effectiveness of QMF-EMT is demonstrated through its application to the statistical analysis of two test networks. Validation is performed by comparing the results with established techniques, including PSCAD/EMTDC and the Numerical Laplace Transform (NLT) method. The case studies include the integration of surge arresters, controlled switching operations as overvoltage (OV) mitigation measures, and a large-scale network comprising 39 three-phase nodes. Notably, QMF-EMT's high computational speed on conventional CPUs enables efficient determination of the required number of events and integration steps for statistical analyses. This work underscores QMF-EMT's potential as a transformative tool for addressing computational challenges in EMT studies, particularly in large-scale power-systems.This work was supported in part by the National Council of Science and Technology (CONACYT), Mexico, under Grant No. 1074592. The work of Luis A. Garcia-Reyes received funding from the ADOreD project, part of the European Union’s Horizon Europe Research and Innovation Programme, under the Marie Skłodowska-Curie Grant Agreement No. 101073554.Peer ReviewedPostprint (published version