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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
Behavior of cohesive stresses in embedded finite elements based on the strong discontinuity approach
No full text© 2025 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.Embedded finite element formulations have gained increased attention for modeling strong discontinuities in solid mechanics problems, as they eliminate the need for mesh conformity required by discrete fracture models. While several such formulations have been extensively studied, particularly regarding strategies to mitigate stress locking, less is understood about the causes and possible remedies to the spurious stress oscillations along cohesive discontinuities. In this work, we employ the Enhanced Assumed Strain framework to derive two of the most popular formulation types: the Kinematically Optimal Symmetric (KOS) and the Statically and Kinematically Optimal Nonsymmetric (SKON). We investigate their performance in a broad range of scenarios, including stick and slip contact conditions, in both two and three dimensions, using linear and quadratic finite elements. Our results show that the SKON formulation consistently yields smoother cohesive stress fields by enforcing local equilibrium in a strong sense. While spurious oscillations are effectively eliminated under stick conditions, small-amplitude oscillations may persist under slip conditions; however, they are significantly reduced compared to the KOS formulation. Finally, we demonstrate the application of the SKON formulation to a fault reactivation problem, confirming its capability to accurately capture stress evolution and assess fault reactivation risk.This research was carried out in association with the ongoing R&D project “Risk assessment of geological fault reactivation by CO injection” (PUC-Rio/ ExxonMobil Exploração Brasil Ltda./ ANP) sponsored by ExxonMobil Exploração Brasil Ltda. under the ANP R&D levy regulation and ANP project number 23449-2. The authors acknowledge the financial support of the Brazilian National Council for Scientific and Technological Development (CNPq) Grants 315077/2023-9 and 308056/2022-1; Carlos Chagas Filho Foundation for Supporting Research in the State of Rio de Janeiro (FAPERJ) Grants E-26/200.463/2023 and E-26/201.391/2021. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001.Peer ReviewedPostprint (published version
Col·lecció de pràctiques d'Introducció a les comunicacions (ICOM)
No full textCol·lecció de pràctiques d'"Introducció a les comunicacions" (ICOM) - Escola Tècnica Superior d'Enginyeria de Telecomunicació de Barcelona (ETSETB)2025/20262n quadrimestr
A logratio approach to the analysis of autosomal genotype frequencies across multiple samples
No full textMore than 25¿years ago, Aitchison showed that the logratio principal component analysis of multiple samples of a biallelic polymorphism can evidentiate the Hardy–Weinberg law. However, hitherto compositional data analysis, that is, the logratio approach, has had little impact in population genetics. This article extends Aitchison's work to multiallelic polymorphisms showing how the Hardy–Weinberg law manifests itself in a logratio based statistical analysis with larger genotypic compositions. Excellent visualisations of equilibrium and disequilibrium are achieved by using compositional biplots based on allele and genotype frequencies taken across multiple populations. Some fundamental relationships between allelic and genotypic compositions are derived, and the close relationships between the logratio principal component analysis of allelic and genotypic compositions and the corresponding compositional biplots are established. Simulations and practical genetic data analysis are used to explore the implications of Hardy–Weinberg equilibrium for the logratio principal component analysis of genotypic compositions. A general multiallelic compositional measure for disequilibrium is presented, and shown to relate to the classical inbreeding coefficient. The proposed compositional analysis is illustrated with biallelic glyoxalase genotypes and with two multiallelic loci from the 1000 Genomes project, the forensic microsatellite D2S441 and the ABO locus. For the latter, a haplotype based approach is used and generates predictions of the three-allele ABO genotypes for the individuals of the expanded 1000 Genomes project.This work was supported by the Spanish Ministry of Science and Innovation and the European Regional Development Fund under grant PID2021-125380OB-I00 (MCIN/AEI/FEDER).Peer ReviewedPostprint (published version
Magnetic resonance image enhancement and segmentation using conventional and deep learning denoising techniques for dynamic cerebral angiography
No full textThe study of brain vascular dynamic patterns in infants, through dynamic angio MRI (TRANCE-MRI) images, is relevant to identify pathologies associated with brain flow and perfusion. However, several drawbacks arise while using these types of images for diagnosis, such as noisy images and difficulties in the quantification of the vessel patterns. Depending on the patient, specialists can use manual procedures to analyze the images and segment the veins during the image analysis. Image acquisition in infants is often affected by motion artifacts, variable contrast due to short acquisition times, and scanner hardware limitations, which together increase noise and reduce vessel visibility. Furthermore, this fact poses serious challenges for both the use of AI tools as well as the analysis and diagnosis of professionals. The goal of this research is to assess automatic denoising pipelines for enhancing image quality to aid visual analysis and automated vessel segmentation for improved quantification through vessel feature extraction. As a result of this research, an entire pipeline is presented as a solution. For denoising the images, we have explored the combination of conventional techniques with unsupervised techniques based on deep learning. The outcomes were subjectively assessed by experts and quantitatively by non-reference image quality evaluators. Using Noise2Void and PPN2V GMM produced the best outcomes, according to the scores. However, employing a combination of traditional methods and deep learning-based methods, the vessels showed a reduction in noise in the central and most dense areas, according to qualitative results. A model was trained using noisy images for segmentation. Then it was put to the test using both denoised and noisy images. The findings demonstrated an improvement of 9.4% in the dice score and nearly 16% in the Hausdorff distance when the model was trained using noisy images and segmentation was obtained using denoised images.Peer ReviewedPostprint (author's final draft
Shear strengthening and anchorage effects of CFRP U-wraps in flexurally strengthened reinforced concrete beams
No full textThis study investigates the combined effects of shear strengthening and anchorage provided by carbon fiber–reinforced polymer (CFRP) U-wraps in reinforced concrete beams strengthened in flexure using externally bonded CFRP sheets. Eighteen large-scale T-beams, divided into three groups based on the internal steel shear reinforcement ratio, were strengthened with flexural CFRP sheets and different configurations of unanchored U-wraps and U-wraps anchored with fiber anchors. Experimental results confirmed that U-wraps can effectively serve as supplemental shear reinforcement while simultaneously providing anchorage for flexural CFRP. U-wraps anchored with fiber anchors changed the failure modes of two shear-deficient beams from shear failure to flexural failure and increased the strain in flexural CFRP to its rupture strain. In the flexure-controlled group, U-wraps shifted the failure mode from intermediate crack debonding to U-wrap rupture or debonding, or concrete crushing, with a flexural CFRP strain increase from 45% to 55% compared to the unanchored strengthened specimen. The experimental results were compared with the analytical results computed using the current design guidelines and codes, which were more conservative for flexure-controlled specimens than for shear-controlled specimens.The authors gratefully acknowledge funding provided under Subaward no. 5903-UD-DOT-7103 to the University of Delaware by the US Department of Transportation (USDOT)—Center for Integrated Asset Management for Multimodal Transportation Infrastructure Systems (CIAMTIS) at the Pennsylvania State University (Federal grant no. 69A3551847103). The authors also thank Simpson Strong-Tie Co., Inc., for partially funding the project and donating the materials, and Structural Technologies, LLC, for installing the FRP. In addition, the authors thank Gary Wenczel, manager of the University of Delaware Structural Engineering Laboratory, for providing technical support for the structural testing. The expressed findings and opinions in this paper are those of the authors and do not necessarily reflect the views of the USDOT, CIAMTIS, Simpson Strong-Tie Co., Inc., or Structural Technologies, LLC.Peer ReviewedPostprint (author's final draft
DINÀMICA DE SISTEMES (Examen final 1r quadrimestre)
No full textProblemesResolved2025/20261r quadrimestr
MÀQUINES ELÈCTRIQUES (Examen final 1r quadrimestre)
No full textProblemesResolved2025/20261r quadrimestr
Estudi i disseny d'un pla de formació i manteniment per un centre de mecanitzat CNC SCM
No full textEn aquest projecte es du a terme la intenció de dissenyar un pla de formació i un pla de manteniment per un centre de mecanitzat CNC SCM per l’empresa Sucade, enfocada especialment en mecanització per CNC de materials plàstics. El projecte es centra principalment en les dificultats de mecanitzar aquests materials, ja que entre tots ells hi ha molta variació de propietats mecàniques i tèrmiques que influeixen directament en els paràmetres de tall i la qualitat dels acabats.
Primerament, s’abasteix el tema general del mecanitzat i les màquines CNC i es fa una introducció sobre l’evolució, principis de funcionament, característiques, tipus de màquines, diferents materials mecanitzables i diferents tipus d’operacions.
Seguidament, es dissenya el pla de formació en el qual es pretén ensenyar tot el procés de mecanització, des de l'inici d’engegar la màquina SCM, fins a programar-la amb el programari amb el qual es treballa a Sucade anomenat AlphaCam. Es profunditza sobretot en la manera de mecanitzar els diferents tipus de plàstics, analitzant-ne propietats, comportaments davant el tall, eines recomanades i estratègies d’optimització.
A continuació, es presenta el pla de manteniment preventiu per tal de preveure accidents laborals i poder mantenir en un bon estat tot l’equip de treball per millorar la seguretat i la seva durabilitat i fer-ho segons les propostes de canvi presentades.
Finalment, es presenten les conclusions on s'analitza i es valora tot el treball fet, les mesures proposades i la seva contribució a la millora del procés de mecanització dins l’empresa.En este proyecto es llevar a cabo la intención de diseñar un plan de formación y un plan de mantenimiento por un centro de mecanizado CNC SCM por la empresa Sucade, enfocada especialmente a mecanización por CNC de materiales plásticos. El proyecto se centra principalmente en las dificultades de mecanizar estos materiales, ya que entre todos ellos existe mucha variación de propiedades mecánicas y térmicas que influyen directamente en los parámetros de corte y la calidad de los acabados.
Primeramente, se abastece el tema general del mecanizado y las máquinas CNC y se hace una introducción sobre la evolución, principios de funcionamiento, características, tipos de máquinas, diferentes materiales mecanizables y diferentes tipos de operaciones.
Seguidamente, se diseña el plan de formación en el que se pretende enseñar todo el proceso de mecanización, desde el inicio de arrancar la máquina SCM, hasta programarla con el software con el que se trabaja en Sucade llamado AlphaCam. Se profundiza sobre todo en la forma de mecanizar los diferentes tipos de plásticos, analizando propiedades, comportamientos frente al corte, herramientas recomendadas y estrategias de optimización.
A continuación, se presenta el plan de mantenimiento preventivo para prever accidentes laborales y poder mantener en buen estado a todo el equipo de trabajo para mejorar la seguridad y su durabilidad y hacerlo según las propuestas de cambio presentadas.
Por último, se presentan las conclusiones donde se analiza y se valora todo el trabajo realizado, las medidas propuestas y su contribución a la mejora del proceso de mecanización en la empresa.This project focuses on developing a comprehensive training plan and a maintenance plan for an SCM CNC machining center used at Sucade, a company specializing in CNC machining of plastic materials. The work places particular emphasis on the challenges involved in machining plastics, as their widely varying mechanical and thermal properties have a direct impact on cutting parameters and the quality of the final finish.
The project begins with an overview of machining and CNC technology, introducing their evolution, operating principles, key features, machine types, machinable materials, and the main types of machining operations.
It then moves on to the design of the training plan, which aims to guide new operators through the complete machining process—from powering up the SCM machine to programming it using AlphaCam, the software employed at Sucade. Special attention is given to machining different types of plastics, analyzing their properties, behavior during cutting, recommended tooling, and optimization strategies.
Next, a preventive and corrective maintenance plan is presented to help minimize workplace accidents and ensure that all equipment remains in safe and optimal condition, improving both operational safety and machine lifespan in line with proposed improvements.
Finally, the project concludes with an assessment of the work carried out, evaluating the proposed measures and their contribution to enhancing the machining process within the company