System for measurement superconductive materials at microwave frequencies

After the discovery of the Higgs boson, the Conséil Européen pour la Recherche Nucléaire (CERN) started a new research study for the foundation of a new particle accelerator that would extend the energy frontier in the research of particle physics, the Future Circular Collider (FCC). This degree thesis is performed in the framework of a consortium project between CERN, Universitat Polit ècnica de Catalunya (UPC), CELLS/ALBA Synchrotron Light Source, Institut de Ci`encies Materials de Barcelona (ICMAB) and Institut de Física d¿Altes Energies (IFAE) and as the continuation of the work realized in ALBA¿s internship, which tries to characterize the coating materials employed in the beam pipe of the hadron-hadron collider of the FCC accelerator (FCC-hh). The purpose of this thesis is the design, study, fabrication, and test of a parallel plate resonator (PPR) capable of measuring the surface impedance of High-Temperature Superconductor Coated Conductors (HTS-CC) at frequencies around 2 kHz and 4 GHz to evaluate if the HTS-CC of some providers fulfill the electromagnetic conditions required for the beam pipe¿s coating. The design is intended to be employed in a 16T cryostat at temperatures around 20 K and 100K to simulate the requirements of the accelerator. Nevertheless, in this thesis, we will only test a preliminary prototype in a 0T Janis cryostat using copper samples. The fundamental mode TEM1,0 is the only resonance mode that must be operable for surface impedance measurements. However, other resonance modes between 1 GHz and 20 GHz will be analyzed to determine if they are also operable or not. The electromagnetic design of the PPR was designed and studied with an electromagnetic (EM) analysis 3D software called CST Studio Suite, whereas the mechanical prototype was designed with a 3D design software called Autodesk Fusion 360. The prototype was manufactured in the UPC¿s workshop, and the samples of the experimental analysis were processed with an Algorithm for Resonator Parameter Extraction (ARPE) developed by UPC and ALBA.Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i InfraestructuraObjectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructur

El huerto y el duelo migratorio

Contiene la nota "El caso de Vanessa: El Huerto de la morriña", extracto de un libro de A. Vidal y V. Prades

A transfer Hamiltonian model for devices based on quantum dot arrays

We present a model of electron transport through a random distribution of interacting quantum dots embedded in a dielectric matrix to simulate realistic devices. The method underlying the model depends only on fundamental parameters of the system and it is based on the Transfer Hamiltonian approach. A set of noncoherent rate equations can be written and the interaction between the quantum dots and between the quantum dots and the electrodes is introduced by transition rates and capacitive couplings. A realistic modelization of the capacitive couplings, the transmission coefficients, the electron/hole tunneling currents, and the density of states of each quantum dot have been taken into account. The effects of the local potential are computed within the self-consistent field regime. While the description of the theoretical framework is kept as general as possible, two specific prototypical devices, an arbitrary array of quantum dots embedded in a matrix insulator and a transistor device based on quantum dots, are used to illustrate the kind of unique insight that numerical simulations based on the theory are able to provide

Análisis motivacional en adolescentes. El SMAT (Test de motivaciones en adolescentes)

Terceres Jornades de Foment de la Investigació de la FCHS (Any 1997-1998)El origen de la presente comunicación se sitúa en la realización de las prácticas correspondientes al Curso de Adaptación Pedagógica (C.A.P.) realizado en esta Universidad durante el curso 1997-98. En ellas realizamos una medición de los intereses motivacionales de los alumnos de dos cursos de 3º de B.U.P. a partir de la aplicación del Test de Motivaciones en Adolescentes (SMAT). Nuestro objetivo fundamental era valorar aspectos de la validez criterial del instrumento, en relación a su capacidad predictiva sobre el rendimiento escolar de los alumnos. Para ello, comparamos los resultados obtenidos en la prueba con los resultados académicos de los alumnos en la evaluación que en ese momento estaban realizando

Transport in quantum dot stacks using the transfer Hamiltonian method in self-consistent field regime

The non-coherent rate equation approach to the electrical transport in a serial quantum dot system is presented. The charge density in each quantum dot is obtained using the transfer Hamiltonian formalism for the current expressions. The interactions between the quantum dots and between the quantum dots and the electrodes are introduced by transition rates and capacitive couplings. Within this framework analytical expressions for the current and the charge in each quantum dot are presented. The effects of the local potential are computed within the self-consistent field regime. Despite the simplicity of the model, well-known effects are satisfactorily explained and reproduced. We also show how this approach can be extended into a more general case

Elastic tunneling charge transport mechanisms in silicon quantum dots / SiO2 thin films and superlattices

The role of different charge transport mechanisms in Si /SiO2 structures has been studied. A theoretical model based on the Transfer Hamiltonian Formalism has been developed to explain experimental current trends in terms of three different elastic tunneling processes: (1) trap assisted tunneling; (2) transport through an intermediate quantum dot; and (3) direct tunneling between leads. In general, at low fields carrier transport is dominated by the quantum dots whereas, for moderate and high fields, transport through deep traps inherent to the SiO 2 is the most relevant process. Besides, current trends in Si /SiO2 superlattice structure have been properly reproduced

Estació fotogramètrica digital per a pràctiques de generació cartogràfica

El mètode fotogramètric permet extreure informació mètrica del terreny a partir de mesures fetes sobre fotografies. La generació de la cartografia i dels plànols de les façanes dels edificis són exemples on s’utilitzen majoritàriament la fotogrametria com a eina de mesura. En aquest projecte es vol implementar una estació fotogramètrica que permeti construir el bloc de fotografies, que faci les correccions dels errors sistemàtics i que finalment permeti construir un model tridimensional de l’objecte en estudi, sigui el terreny, un edifici o qualsevol altre objecte físic. La intenció és que pugui executar-se sobre el sistema operatiu Windows instal·lat en ordinadors convencionals, tant els que disposa l’escola a la sala de càlcul com els ordinadors personals de cada estudiant.Peer Reviewe

Comparison of photogrammetric techniques for rockfalls monitoring

The use of Unmanned Aerial Vehicles, UAVs to image capture for monitoring natural hazards has had a major boost for its wide possibilities in the last decade. These are, for example, the studying and monitoring of unstable slopes, glaciers and rocky escarpments. Moreover, to evaluate the risk after a rockfall or debris flow event, for example measuring volume of displaced material, trajectories of blocks or building and/or infrastructure damaged. But the use of these devices requires a specific treatment regarding the studied case and geomatic techniques suitable to get the adequate precision of the movement, size of items or events to study. For each application it is necessary to determine what kind of capture is the most appropriate to obtain an optimal benefit-cost ratio. A comparison of the use of terrestrial photogrammetry, UAV photogrammetry and video from UAV has been done. The best result has been obtained combining techniques aerial and terrestrial since ground points with a best quality can be identified and measured and all the surface has a best image coverage.Peer ReviewedPostprint (published version

Improving the ability of image sensors to detect faint stars and moving objects using image deconvolution techniques

In this paper we show how the techniques of image deconvolution can increase the ability of image sensors as, for example, CCD imagers, to detect faint stars or faint orbital objects (small satellites and space debris). In the case of faint stars, we show that this benefit is equivalent to double the quantum efficiency of the used image sensor or to increase the effective telescope aperture by more than 30% without decreasing the astrometric precision or introducing artificial bias. In the case of orbital objects, the deconvolution technique can double the signal-to-noise ratio of the image, which helps to discover and control dangerous objects as space debris or lost satellites. The benefits obtained using CCD detectors can be extrapolated to any kind of image sensorsPeer ReviewedPostprint (published version