Heat transport with advection in fractured rock

In the transport of heat in porous media, diffusion generally dominates over advection due to slow fluid velocities imposed by low permeability. This is the reason why standard Galerkin formulation leading to extra non-symmetric matrix terms may be still used successfully. However, in the presence of fractures the situation may be different. Fractures constitute preferential flow paths where fluid velocities may be significant and advection may become dominant over diffusion (“large advection” with Péclet number >1). This paper focuses on the formulation, numerical implementation and verification of a model to solve the steady-state heat transport problem with large advection along geomechanical discontinuities represented by zero-thickness interface elements. The fluid velocity field is considered as known input data (no hydraulic coupling). The existing SUPG method is modified for its application to zero-thickness interface elements, and the resulting formulation is implemented in an existing FE geomechanical code. An example of application is presented with large advection along a discontinuity crossing a low permeability domain. The results show that the proposed approach leads to stable results, in contrast to standard Galerkin

Project of attitude control system based on reaction wheels

This project is included in the investigation group PLATHON, which has as the main objective the optical communication between satellites. In this investigation group there are included various parallel projects, which are necessary for the development and experimentation of this project. The objective of this project is the development on an attitude determination and control system (ADCS) of 1 Dof for a CubeSat, based on the usage of reaction wheels. The main interest of the project is to accomplish a physical system that is capable of rotating the system in a controlled way and controlling the orientation of the CubeSat with an acceptable precision. It is intended the system can b integrated in a 1U CubeSat. This work is intended to be tested in a space simulated situation, specifically an airbearing. In this project, the main focus of the work is the development of the software of the ADCS, which has to include mainly the integration of a control of the CubeSats positioning mode. This software must be Open Source, and the resources used must be economic. The software must be able to work in an integrated PCB with all the elements. As this work starts from zero, some designs of circuits, programs and experimentation has been done in order to reach the main point of the project. However, the work shown in this project is focused in the design and development of the software and hardware of the ADCS prototype created. Some tests have been performed on the system in order to determine the reliability and functionality of the design. The design of the software of positioning control has been done by manoeuvres of coarse pointing and fine pointing. Other additional testing modes are included in the code. The code has been designed to be further developed in the future, and even add some possible modes of operation from other projects developed on the fiel

Error recovery system for a RISC-V-like processor

This project is the implementation of an error detection and recovery system on top of the Inkel Pentiun processor, a RISC-V-like processor developed in earlier stages of this Master. The error detection system will detect execution errors caused by transient faults (Single-Event Upsets, or SEUs for short), and is then able to recover the execution to a previous stable point without breaking the intended behaviour of the code being executed. The code for the project is attached as a zip file, but it is also available on my public Git repository, at https://github.com/adriaaap/TFM-Inkel-error-recover

3D-Mesomechanical analysis of cracking and spalling of concrete subject to high temperatures

In this paper, an existing meso-structural model for concrete which had been applied to the study of the mechanical effects of high temperatures in 2D, is extended to 3D, and to more complex coupled thermo-mechanical analysis. The material is idealized as a twophase compositein which all mesh lines (or surfaces in 3D) are potential cracks equipped with fracture-based zero-thickness interface elements. Different thermal expansion laws are assumed for matrix and particles, whereby the deformation mismatch can generate cracking. Temperature distributions are obtained from a separate thermal diffusionanalysis.The thermal analysis is first assumed uncoupled, but then also coupled with the mechanical analysis, as the layers of material spalloff and the boundary conditionsare moved to the new domain boundaries. The new computational results in 3D are compared to basic experimental observations reported in the literature and to the previous computational results obtained in 2D

Estudio del sistema de supervisión y balanceado para baterías híbridas con celdas Li-Ión de Alta Potencia y Alta Energía

La temática del presente estudio se basa en el desarrollo e implementación en laboratorio del sistema de supervisión y balanceado para celdas Li-Ión de Alta Potencia y Alta Energía. En la actualidad los vehículos eléctricos toman cada vez más protagonismo y es necesario desarrollar baterías que sean capaces de satisfacer las necesidades de movilidad actuales. Por esta razón, el trabajo realizado se centra en el desarrollo del monitoreo y supervisión de tensiones de celda y temperatura de un pack de baterías de diferentes tecnologías, como las mencionadas anteriormente. Esta nueva configuración de batería con diferentes tecnologías de celdas en su interior recibe el nombre de batería híbrida. Para el caso de estudio se utilizarán celdas de Alta Energía y Alta Potencia. La celdas de Alta Energía aumenta el contenido global de energía de la batería y aumenta la autonomía. Por el contrario, las celdas de alta potencia, sirven para mejorar la capacidad de potencia y la aceleración. Estas celdas presentan diferentes rangos de tensiones de trabajo entre otros parámetros, por lo cual el sistema de supervisión y balanceado debe ser capaz de poder operar en un amplio rango de tensiones y corrientes. El desarrollo y optimización de baterías de alta tensión, potencia y capacidad energética es una necesidad emergente en el continente europeo. Como ejemplo, se cita el proyecto HELIOS (https://cordis.europa.eu/project/id/963646/es), en el que colabora actualmente la UPC, orientado al desarrollo de un nuevo concepto de baterías modulares, escalables e inteligentes combinando celdas de alta potencia con celdas de alta energía

Sistema de reconstrucció de cavitats en 3D

Les instal·lacions del clavegueram són d’una importància extrema per mantenir una correcta situació d’higiene en una ciutat. Un cop construïdes, és necessari fer-ne un manteniment regular per garantir que segueixen complint la seva funció, però degut a la seva naturalesa subterrània i de conductes foscos i estrets, aquesta no sempre és una tasca senzilla. L’objectiu d’aquest projecte és contribuir al desenvolupament d’una eina que permeti realitzar aquests manteniments d’una forma més senzilla, segura i eficient. Aquesta eina està sent desenvolupada pel departament d’ESAII de la UPC, per petició de l’empresa de Fomento y Contratas (FCC), els encarregats actualment de fer el manteniment del clavegueram de Barcelona. La seva finalitat principal serà l’exploració d’embornals, que tot i ser la part del clavegueram que més a prop es troba de la superfície, no resulten fàcils d’obrir i inspeccionar, motiu pel qual es vol un aparell que pugui realitzar el procés d’exploració de forma directa i sense necessitat d’aixecar-ne la reixa. El projecte consistirà en desenvolupar una part del software d’aquesta eina. Concretament, es centra al voltant del disseny d’un algorisme que permeti convertir un conjunt de punts capturats en un espai en 3D i que representen l’interior d’aquest embornal a una dada numèrica que indicarà quin percentatge de la canonada que connecta amb el sistema de clavegueram principal està obstruïda, perquè l’equip de manteniment pugui valorar si és necessari accedir a l’embornal per fer una neteja o no.Las instalaciones de alcantarillado son de una importancia extrema para mantener una correcta situación de higiene en una ciudad. Una vez construidas, es necesario realizarles un mantenimiento regular para garantizar que siguen cumpliendo su función, pero debido a su naturaleza subterránea y de conductos oscuros y estrecho, ésta no siempre resulta tarea fácil. El objetivo de este proyecto es contribuir al desarrollo de una herramienta que permita realizar estos mantenimientos de una forma mas sencilla, segura y eficiente. Esta herramienta esta siendo desarrollada por el departamento de ESAII de la UPC, por petición de la empresa Fomento y Contratas (FCC), los actuales encargados de hacer el mantenimiento del alcantarillado de Barcelona. Su finalidad principal será la exploración de imbornales, que aunque són la parte del alcantarillado más cercana a la superfície, no resultan fáciles de abrir e inspeccionar, motivo por el qual se desea un aparato que sea capaç de realizar el proceso de exploración de forma directa y sin necesidad de levantar la reja. El proyecto consistirá en desarrollar una parte del software de esta herramienta. Concretamente, se centra alrededor del diseño de un algoritmo que permita convertir un conjunto de puntos capturados en un espacio de 3D y que representan el interior de este imbornal en un dato numérico que indicará que porcentage de la cañería que conecta con el sistema principal de alcantarillado está obstruída, para que el equipo de mantenimiento pueda valorar si es necesario acceder al interior para realizar una limpieza o no.In any city, sewer installations are of major importance to help maintain a correct hygienic state. Once built, it’s necessary to do regular maintenance on them to guarantee they keep accomplishing their function properly. Provided they are built in an underground System filled with dark and small conduits, this is not usually an easy task. The aim of this project is to contribute to the development of a tool that aids in doing this maintenance in an easier, safer and more eficient way. This tool is being developed by the UPC’s ESAII department by petition of the Fomento and Contratas company, the corrent responsables for doing Barcelona’s city sewer maintenance. It’s main purpose is the exploration of scuppers, which even though are the most superficial part of the sewer System, are not particularly easy to open and examine manually. For this reason, the company wants a device capable of doing this exploration process directly and without even needing to lift the case. This project will be centered around the developing a part of the software for this device. In particular, we want to design an algorithm that is capable of transforming a particular set of points in a 3D space which represent the inside of a scupper into a numerical value which indicates the portion of the pipe connection to the main draining system is obstructed. This value will help the maintenance team in taking a decision regarding wether to manually access the scupper for cleaning or not

Control de movimientos de ladera en el Pirineo Oriental con técnicas avanzadas

El presente trabajo se centra en el estudio de desplazamientos superficiales de laderas inestables a partir de técnicas de monitorización diversas, estudiando el caso particular de una ladera localizada en los Pirineos Orientales y monitorizada desde los años 1980 por la Universidad Politécnica de Catalunya (ladera de Vallcebre, Comarca de Berguedà)

Transient large heat advection in fractured rock: a zero-thickness interface formulation

In a fractured rock mass, the existence of discontinuities may generate preferential paths where the hydraulic flow velocities are frequently much higher than in the porous medium and heat advection tends to dominate over heat diffusion. In these cases, the standard Galerkin FEM method leads to oscillatory results and requires the use of stabilization methods. Thus, the current paper introduces a 3-D formulation to solve the large advection problem for zero-thickness interface elements –which may be used to discretize fractures in a FEM context–, based on a pre-existent Characteristic method. A verification example is presented, showing that the formulation exhibits a good performance to represent the heat transport by the fluid along zero-thickness interface elements.This work was partially supported by research grant BIA2016-76543-R from MEC (Madrid), which includes European FEDER funds, and 2017SGR-1153 from Generalitat de Catalunya (Barcelona). The first author also acknowledges his FPU scholarship from MEC (Madrid).Postprint (published version

Heat transport with advection in fractured rock

In the transport of heat in porous media, diffusion generally dominates over advection due to slow fluid velocities imposed by low permeability. This is the reason why standard Galerkin formulation leading to extra non-symmetric matrix terms may be still used successfully. However, in the presence of fractures the situation may be different. Fractures constitute preferential flow paths where fluid velocities may be significant and advection may become dominant over diffusion (“large advection” with Péclet number >1). This paper focuses on the formulation, numerical implementation and verification of a model to solve the steady-state heat transport problem with large advection along geomechanical discontinuities represented by zero-thickness interface elements. The fluid velocity field is considered as known input data (no hydraulic coupling). The existing SUPG method is modified for its application to zero-thickness interface elements, and the resulting formulation is implemented in an existing FE geomechanical code. An example of application is presented with large advection along a discontinuity crossing a low permeability domain. The results show that the proposed approach leads to stable results, in contrast to standard Galerkin.Postprint (published version