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Differential entropy of digital pictures

  • Grifell Guàrdia, Laia
En el treball s'estudia la compressió JPEG i la seva possible utilitat com a clau en criptografia. Es fa mitjançant comparant les compressions JPEG d'imatges en RAW molt semblants.
Proyecto:


Necesidad del geoide en el posicionamiento con GPS

  • Núñez Andrés, María Amparo
  • Buill Pozuelo, Felipe
The common use of global positioning systems, and specially GPS, in work like survey, cartography, photogrammmetry, LIDAR... make it necessary have a gemid model to transform ellipsoidal to orthometric heights used in engineering. Because of the lack of parallelism between both reference systems not to have these models can produce important errors since the variation can take values of 10cm/Km or more in some areas, for example in the SW of Spain. If we do not consider this difference in the elaboration of DTM used to design substructure can happen that in gravity canalization the water does not arrive at the wanted point
Proyecto:


Fabrication of c-Si microstructures through reorganization at high temperatures, Fabricación de microestructuras de c-Si mediante reorganización a altas temperaturas, Fabricació de microestructures de c-Si mitjançant la reorganització a altes temperatures

  • Solà Garcia, Maria Magdalena
Silicon photonics has gained increasing interest in recent years as it promises high performance, cost-effective integrated optical devices. The advent of Si fabrication techniques at the micro and nano-scales, in conjunction with the interesting optical properties of this material, such as its high refractive index, has enabled the development of new methods of light confinement. In particular, Si microspheres behave as excellent resonators with ultra-high quality factors, resulting in an enhancement in light harvesting. This work presents a new fabrication method of monocystalline Si spheres connected to the substrate, which is also c-Si, through a narrow neck. The fabrication process relies on the surface reorganization in solid phase that occurs when silicon is exposed to high temperatures (above 1100 C). Therefore, initial sharp structures, such as micropillars with relatively high aspect ratios, evolve into rounded shapes, ideally spheres, while keeping attached to the Si bulk through a narrow neck. In this project we fabricate micropillars of varying dimensions and reorganize them through high-temperature annealing at different conditions. As a result, it is proved that the initial aspect ratio together with both the annealing time and atmosphere are decisive in the final shape of the structures. Moreover, they exhibit a faceted surface, confirming that their monocrystalline nature is not altered during the fabrication process. In addition to that, we develop a comparison between the experimental results and the ones obtained through a theoretical model. This analysis shows a satisfactory agreement between both approaches, indicating that the evolution of a given profile can be accurately predicted and simulated. Furthermore, we also verify that the principal mechanism inducing this atomic migration is surface diffusion, in contrast with evaporation/condensation that becomes almost negligible in our experimental conditions., El interés en la fotónica basada en silicio ha aumentado en los últimos años debido a que promete dispositivos económicos y de alto rendimiento. La aparición y avances en las técnicas de fabricación a escalas micro y nano, junto con algunas de las propiedades ópticas de este material, como por ejemplo su alto índice de refracción, han permitido el desarrollo de nuevos métodos para el confinamiento de la luz. En particular, las microesferas de Si se comportan como excelentes resonadores con factores de calidad muy altos, lo que resulta en un mayor aprovechamiento de la luz. Este trabajo presenta un nuevo método de fabricación de esferas monocristalinas de silicio conectadas al sustrato, también de c-Si, a través de un cuello estrecho. El proceso de fabricación se basa en la reorganización de la superficie en estado sólido que ocurre cuando el silicio se somete a altas temperaturas (superiores a 1100 C). De esta forma, estructuras con bordes inicialmente agudos, como micropilares con relaciones de aspecto relativamente altas, evolucionan en formas redondeadas, idealmente esferas, a la vez que se mantienen unidas al silicio mediante un cuello. En este proyecto fabricamos micropilares de dimensiones variadas y los reorganizamos mediante un tratamiento de recocido a altas temperaturas en diferentes condiciones. Demostramos que tanto la relación de aspecto inicial como el tiempo y la atmósfera del proceso de recocido son determinantes en la forma final de las estructuras. Además, éstas presentan una superficie con los planos cristalinos claramente marcados, hecho que confirma que su naturaleza monocristalina no se ve afectada durante el proceso de fabricación. Asimismo, también comparamos los resultados obtenidos experimentalmente y mediante el modelo teórico. Este análisis muestra un acuerdo satisfactorio entre ambos enfoques, hecho que indica que la evolución de un determinado perfil se puede predecir y simular correctamente. Adicionalmente, también verificamos que el mecanismo principal que provoca esta migración atómica es la difusión superficial, en contraste con la evaporación/ condensación, que es prácticamente negligible en las condiciones experimentales dadas., L’interès en la fotònica basada en silici ha augmentat durant els últims anys donat que promet dispositius econòmics i d’alt rendiment. L’aparició i avanç en les tècniques de fabricació a escales micro i nano, junt amb algunes de les propietats òptiques d’aquest material, com per exemple el seu alt índex de refracció, han permès el desenvolupament de nous mètodes per al confinament de llum. En particular, les microesferes de Si es comporten com a excel·lents ressonadors amb factors de qualitat molt alts, fet que permet un major aprofitament de la llum. En aquest treball es presenta un nou mètode de fabricació d’esferes cristal·lines de silici connectades al substrat, també de c-Si, a través d’un coll estret. El procés de fabricació es basa en la reorganització de la superfície en estat sòlid que es produeix quan el silici es sotmet a altes temperatures (superiors a 1100 C). D’aquesta forma, estructures amb vores afilades, com micropilars amb relacions d’aspecte relativament altes, evolucionen en formes arrodonides, idealment esferes, a la vegada que es mantenen unides al silici a través d’un coll. En aquest projecte fabriquem micropilars de diverses dimensions i els reorganitzem mitjançant un tractament de recuita a altes temperatures en diferents condicions. Demostrem que tant la relació d’aspecte com el temps i l’atmosfera del procès de recuita són determinants per a la forma final de les estructures. A més, aquestes presenten una superfície amb els plans cristal·lins clarament marcats, fet que confirma que la seva naturalesa monocristal·lina no es veu afectada durant el procés de fabricació. Així mateix, també comparem els resultats obtinguts experimentalment i mitjançant el model teòric. Aquest anàlisi mostra un acord satisfactori entre ambdós enfocaments, fet que indica que l’evolució d’un determinat perfil es pot predir i simular correctament. Addicionalment, també verifiquem que el mecanisme principal que provoca aquesta migració atòmica és la difusió superficial, en contrast amb l’evaporació/condensació, que és pràcticament negligible en les condicions experimentals donades.
Proyecto:


Design of the body of a martian vehicle for the European Rover Challenge

  • Izquierdo Moliner, Alberto
During history, there have been a lot of designing regarding martian rovers. In the following thesis the body of one of those rovers has been designed, meeting the requirements of the European Rover Challenge. Firstly, some of the main components have been described in order to design the body properly. After discussing three ideas regarding the body shape and components distribution; and three possible materials; one is chosen. The body has been designed using a structure profile with a profile substructure and aluminium plates to withstand the weight requirements. Furthermore, aluminium sheets are used to seal the body. In this way, the resulting body is pretty lightweight. In addition, a stress analysis has been performed in order to check if the structure is stiff enough. The results are satisfactory. The usage of prefabricated profiles and their connectors allows designing an affordable product, with a sufficient stiffness and enough quality. There are a lot of possibilities of application of the rover.
Proyecto:


Disseny en planta pel projecte de millores de sanejament al terme municipal de Riells i Viabrea i al nucli de la Batllòria al terme municipal de Sant Celoni

  • Farrerons Vidal, Óscar
El municipi presenta una xarxa de clavegueram unitària, absolutament fragmentada, existeixen trams de recollida dels diferents sectors, però sense continuïtat ni finalització en elements de tractament de les aigües, el qual suposa que una vegada canalitzades en un determinat recorregut, acaben abocant a les rieres que travessen el territori, o a pous que es troben fora de servei útil, fet que suposa una situació de precarietat des d'un punt de vista funcional admissible. El que pretén el present projecte es complementar i connexionar aquesta xarxa existent mitjançant nous trams de col•lector i les oportunes estacions de bombament.
Proyecto:


Urban automation networks: current and emerging solutions for sensed data collection and actuation in smart cities

  • Gómez Montenegro, Carlos
  • Paradells Aspas, Josep
Urban Automation Networks (UANs) are being deployed worldwide in order to enable Smart City applications. Given the crucial role of UANs, as well as their diversity, it is critically important to assess their properties and trade-offs. This article introduces the requirements and challenges for UANs, characterizes the main current and emerging UAN paradigms, provides guidelines for their design and/or choice, and comparatively examines their performance in terms of a variety of parameters including coverage, power consumption, latency, standardization status and economic cost.
Proyecto:


Enhanced electromagnetic interference shielding effectiveness of polycarbonate/graphene nanocomposites foamed via 1-step supercritical carbon dioxide process

  • Gedler, Gabriel
  • Antunes, Marcelo de Sousa Pais
  • Velasco Perero, José Ignacio
  • Ozisik, Rahmi
The dielectric and electromagnetic interference (EMI) shielding properties of polycarbonate/graphene nanocomposites foamed using supercritical carbon dioxide were studied as a function of their cellular and compositemorphology. Foamed polycarbonate filled with 0.5% (by weight) graphene exhibited enhanced EMI shielding effectiveness, which was found to depend on cellular and composite morphology in a complex manner. Foamed composites presented a maximum specific EMI shielding effectiveness of ~39 dB cm3/g, which is approximately 35 times greater than that of unfoamed composite (1.1 dB cm3/g). In addition, the relative permittivity was found to increase up to 3.25 times. The results suggest that graphene filled polymer foams can enhance the performance of electronic devices, opening up the possibility of using these materials in electronic applications., Peer Reviewed
Proyecto:


A parallel finite-element method for three-dimensional controlled-source electromagnetic forward modelling

  • Puzyrev, Vladimir
  • Koldan, Jelena
  • de la Puente, Josep
  • Houzeaux, Guillaume
  • Vázquez, Mariano
  • Cela, José M.
We present a nodal finite-element method that can be used to compute in parallel highly accurate solutions for 3-D controlled-source electromagnetic forward modeling problems in anisotropic media. Secondary coupled-potential formulation of Maxwell’s equations allows to avoid the singularities introduced by the sources, while completely unstructured tetrahedral meshes and mesh refinement support an accurate representation of geological and bathymetric complexity and improve the solution accuracy. Different complex iterative solvers and an efficient preconditioner based on the sparse approximate inverse are used for solving the resulting large sparse linear system of equations. Results are compared with the ones of other researchers in order to check the accuracy of the method. We demonstrate the performance of the code in large problems with tens and even hundreds of millions of degrees of freedom. Scalability tests on massively parallel computers show that our code is highly scalable., Funding for this work was provided by the Repsol-BSC Research Center. The authors acknowledge Repsol for permission to submit this paper. All numerical tests were performed on MareNostrum Supercomputer of the Barcelona Supercomputing Center. VP wishes to express his gratitude for hospitality during his visit to Texas A&M University. The authors would like to thank Dr. Christoph Schwarzbach for providing additional information on their results and the Editor, Dr. Gary Egbert, and two anonymous reviewers for their suggestions that helped to improve the presentation of this paper., Peer Reviewed
Proyecto:


Design and implementation of a calculation program in Matlab platform for evaluation of roughness

  • Villanueva Baygual, Juan de
Nowadays, the automotive sector requires great quality for each product that is produced, and especially regarding those pieces or parts which need to be reliable and long lasting, and that require high properties because of their use. High temperatures, high pressures or constant friction are effects that some pieces in the engine, for example, have to endure during its working life, which is of around fifteen to seventeen years. It is precisely in the automobile’s engine where pieces suffer the most aggressive effects, and therefore, where the fabrication has to be optimized to achieve its goals. Inside the engine, with its high temperatures, great movement and extenuating friction, the piston has to find a perfect measurement in roughness in order to avoid arriving to such aggressive conditions. This is done by maintaining the oil and the fuel separated but retaining the oil to a certain level to avoid excessive friction piston-cylinder. Therefore, the study of roughness regarding fabrication of these pieces is extremely important, and in addition to this, the realization of where it can be improved and where it cannot. This paper studies a way of differentiating the various frequencies of a surface profile. First, it analyses the primary surface properties to figure out what differentiates frequencies within a sample. Then, it studies which values assigned, regarding the properties, act in a filter to differentiate frequencies. Finally, it arrives to the conclusion of what is roughness and what is waviness and their specific properties.
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