Design, fabrication and characterization of photonic crystals for cavity quantum electrodynamics enhanced devices

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física de Materiales: Fecha de lectura: 13-06-2014In this thesis, photonic crystals with embedded quantum nanostructures were used to achieve enhanced devices for cavity quantum electrodynamics experiments. We have developed several fabrication procedures to obtain state{of{the{ art photonic crystal microcavities. Several applications have been demonstrated along the course of this thesis. Some of them are presented in this manuscript. First, near{thresholdless laser operating at room temperature was demonstrated in a system consisting of a L9{photonic crystal microcavity with embedded single layer of high density of InAsSb/GaAs quantum dots. Second, a methodology was presented to study the strong coupling between quantum nanostructures and cavity modes with high quality factor and low volume by means of nite di erence time domain. Third, three di erent approaches have been proposed towards the deterministic coupling of a single quantum dot with a photonic crystal microcavity mode. Results are based on the development of a strategy either to fabricate PCMS in spectral and spatial speci c positions or to specify those positions where the QDs have to be nucleated. To fabricate PCMs in speci c positions we have developed a fabrication procedure of photonic crystal microcavities with metallic marks, achieving an accuraccy in the spatial positioning better than 50 nm. Molecular beam epitaxial re{growth of pre{patterned photonic crystal microcavities in a incomplete GaAs slab have been designed, fabricated and tested to demonstrate their capability to integrate one or several isolated QDs. Finally, an enhanced external quantum e ciency in solar cells was demonstrated through the use of a photonic crystal.En esta tesis, se ha utilizado cristales fotónicos con nano{estructuras cuánticas para conseguir fabricar dispositivos mejorados para experimentos de electrodinámica cuántica en cavidades. Hemos desarrollado varios procesos de fabricación para obtener microcavidades de cristal fotónico en el estado del arte. Varias aplicaciones han sido demostradas durante el curso de esta tesis. Algunas de ellas son presentadas en este manuscrito. En primer lugar, un laser quasi{sin{ umbral a temperatura ambiente ha sido demostrado en un sistema que consiste en una cavidad de cristal fotónico con una única capa de puntos cuánticos de InAsSb/GaAs de alta densidad. En segundo lugar, se presenta una metodología para estudiar el acoplamiento fuerte entre nanostructuras cuánticas y modos de cavidad con alto factor de calidad y bajo volumen modal mediante diferencias fi- nitas en el dominio temporal. En tercer lugar, se proponen tres aproximaciones para la obtención de un sistema de punto cuántico acoplado de forma determinista con un modo de cavidad de cristal fotónico. Los resultados están basados en el desarrollo de una estrategia, bien de la fabricación de cavidades de cristal fotónico en posiciones específicas emitiendo en determinadas longitudes de onda, bien especificando el lugar donde se tienen que nuclear los puntos cuánticos. Para fabricar las cavidades de cristal fotónico en posiciones espeíficas hemos desarrollado un procedimiento de fabricación que hace uso de marcas metálicas de alineamiento, y hemos demostrado precisiones en el posicionamiento mejores que 50 nm. Se han conseguido cavidades fabricadas en una lámina incompleta y luego recrecidas mediante la técnica de crecimiento por haces moleculares y se ha demostrado su potencial para incorporar uno o varios puntos cuánticos posicionados. Finalmente, hemos demostrado una mejora en la e ciencia cuántica de células solares mediante el uso de cristales fotónico

Large Eddy Simulation (LES) Aplicado a un lecho fluidizado gas – sólido. Parte I: Reactor a escala de laboratorio

Los reactores de lecho fluidizado son equipos utilizados en la industria de hidrocarburos, para procesos heterogéneos gas-sólido, tanto catalíticos como no catalíticos. Las aplicaciones industriales más importantes incluyen el cracking catalítico, combustión y/o gasificación de carbón, biomasa y residuos sólidos, entre otros. En este trabajo se estudia el comportamiento fluidodinámico gas-solido, usando técnicas computaciones de Dinámica de Fluidos (CFD) en un lecho fluidizado a nivel laboratorio de 1 m de longitud y 5 cm de altura de lecho, se implementó la metodología de Large Eddy simulation (LES) y mallas casi-uniformes construidas previo cálculo de las micro escalas turbulentas. Las simulaciones fueron validadas con datos de la literatura, logrando describir el comportamiento de descenso de partículas (annulus) , sin necesidad de refinamiento cerca de la pared y mejorando el tiempo de computo en comparaciones con simulaciones realizadas usando RANS.The fluidized bed reactors are commonly used in the petrochemical industry, with applications in catalytic and non-catalytic processes. An important use of this technology includes the catalytic cracking, as well as the gasification of coal, biomass and solid waste. This work studied the fluid dynamics inside a lab scale fluidized bed, which was 1 meter long with 5 cm bed height. The study was carried out using Computational Fluid Dynamics (CFD), including the use of Large Eddy Simulation methodology (LES), in addition to the use of a quasi-uniform computational grid, which was created before the micro scale turbulence calculation. Therefore, it was possible to describe the behavior of the particles at annulus of the unit, without the need of having a refined grid near the wall. This resulted in an improvement on the required calculation time compared to the simulations that use the RANS methodology. The simulation results showed good agreement with the data reported in literature

Effect of teaching method on exercise execution in adolescents’ use of outdoor fitness equipment

The use of outdoor fitness equipment (OFE) is an effective strategy to promote physical activity. The equipment normally includes information panels with phrases and images describing appropriate exercises. However, as using this equipment inappropriately is a potential problem, it is important to find an optimal unsupervised instruction method for correct exercise execution. Our objective in this study was to determine which of several exercise prescription methods, without direct professional supervision, might best instruct adolescents to correctly engage in upper limb motor execution on outdoor flexion-extension equipment. A total of 54 adolescents from a middle socioeconomic level in northwest Spain participated in this descriptive and quasi-experimental study. We randomly assigned members of this convenience sample into three groups who received either video instruction, instruction via images or written panel instructions. We used observational methodology in videographic analysis to evaluate the mistakes participants made in motor execution with each instructional method. We utilized different analytic techniques from observational methodology: statistical analyses (means, standard deviation, confidence intervals, ANOVA, etc.) and detecting T-Patterns with Theme and polar coordinate analysis using HOISAN. Participants who relied on video instructions committed fewer errors than those who relied on panel instructions. The video method prevented loss of information that occurred when instructional images were used. We suggest including a QR code on outdoor fitness equipment in open-air parks to permit users to download an explanatory video to their mobile phones

Large Eddy Simulation (LES) Aplicado a un lecho fluidizado gas – sólido. Parte I: Reactor a escala de laboratorio

Los reactores de lecho fluidizado son equipos utilizados en la industria de hidrocarburos, para procesos heterogéneos gas-sólido, tanto catalíticos como no catalíticos. Las aplicaciones industriales más importantes incluyen el cracking catalítico, combustión y/o gasificación de carbón, biomasa y residuos sólidos, entre otros. En este trabajo se estudia el comportamiento fluidodinámico gas-solido, usando técnicas computaciones de Dinámica de Fluidos (CFD) en un lecho fluidizado a nivel laboratorio de 1 m de longitud y 5 cm de altura de lecho, se implementó la metodología de Large Eddy simulation (LES) y mallas casi-uniformes construidas previo cálculo de las micro escalas turbulentas. Las simulaciones fueron validadas con datos de la literatura, logrando describir el comportamiento de descenso de partículas (annulus) , sin necesidad de refinamiento cerca de la pared y mejorando el tiempo de computo en comparaciones con simulaciones realizadas usando RANS.The fluidized bed reactors are commonly used in the petrochemical industry, with applications in catalytic and non-catalytic processes. An important use of this technology includes the catalytic cracking, as well as the gasification of coal, biomass and solid waste. This work studied the fluid dynamics inside a lab scale fluidized bed, which was 1 meter long with 5 cm bed height. The study was carried out using Computational Fluid Dynamics (CFD), including the use of Large Eddy Simulation methodology (LES), in addition to the use of a quasi-uniform computational grid, which was created before the micro scale turbulence calculation. Therefore, it was possible to describe the behavior of the particles at annulus of the unit, without the need of having a refined grid near the wall. This resulted in an improvement on the required calculation time compared to the simulations that use the RANS methodology. The simulation results showed good agreement with the data reported in literature

Validation of two instruments for the correct allocation of school furniture in secondary schools to prevent back pain

Background: Back pain is common in secondary school students. If we adjust the school furniture to the anthropometric characteristics of the pupils, we will improve their posture and reduce back pain. There is a high degree of mismatch between the furniture used by students and that which should be used. The objectives of this research are to discover the degree of mismatch and validate two instruments that allow a correct allocation of the furniture. Methods: The selected sample was 132 secondary students (14.08 ± 1.10 years). An anthropometer was used to determine the ideal height of the chair and table; data were taken from body segments. The recorded values were compared with those obtained by the two measurement instruments to be validated. Inter-measurer and intra-measurer reliability and validation were performed using t-tests and Pearson’s coefficient, respectively. Different analysis techniques were used: descriptive, one-way ANOVA, t-test, and effect size. The established level of significance was ρ < 0.05. Results: The mismatch between the anthropometric dimensions of the students and the existing furniture in the classrooms was 98.5 % for the chairs and 100 % for the tables. The correlational analysis of the instruments to be validated shows an r = 0.993 in the chair and r = 0.996 in the table. Conclusions: There is a high degree of mismatch between the furniture and the anthropometric characteristics of the students. The proposed furniture allocation instruments are adequate

Detección de T-patterns en la observación de deportes de combate

By identifying and analysing temporal patterns (T-patterns) in behaviour, this study aims to detect technical errors and behavioural sequences in the kosoto gari judo throw, and, based on this, to propose changes to the way in which judo is taught. The participants (n = 50: 38 men and 12 women; Mage = 19.23 years, SD = 1.12) were students studying for a physical education and sports science degree with no previous experience of judo. This was a systematic observational study in which the students were filmed performing the kosoto gari technique. The results, derived from descriptive statistics and a sequential analysis of T-patterns conducted by means of Theme 5, revealed that the students committed a series of typical errors when learning to perform the throw. Furthermore, these errors often appeared in sequence, mainly involving a lack of balance, the position of the feet and hips/trunk, an incorrect reap and the final arm movement. The results can be used to propose movement sequences that would ensure that the throw is learnt correctly, and also to enable recommendations to be made regarding the use of feedback.El objetivo de esta investigación es implementar el análisis y detección de las estructuras temporales de los acontecimientos deportivos o patrones temporales o T-pattern para detectar los errores técnicos y sus secuencias conductuales en la proyección de judo kosoto-gari y así proponer cambios metodológicos en los procesos de enseñanza del judo. Los participantes (n = 50; 38 hombres y 12 mujeres; M = 19.23 años; DE = 1.12), estudiantes del grado en CAFE sin experiencia previa en judo, se sometieron, a partir de un estudio observacional sistemático, a un registro en video de la ejecución de la técnica de estudio. Los resultados, determinados mediante estadística descriptiva y análisis secuencial de T-Patterns obtenido con el programa Theme 5, corroboran que existe una serie de defectos típicos que comete el sujeto en el aprendizaje de esta proyección, así como unas secuencias de errores en cadena, que básicamente afectan al desequilibrio, a la posición de los pies y cadera-tronco, a la incorrecta acción de siega y a la acción final de los brazos. Estos resultados nos permiten proponer, en el aprendizaje del judo, secuencias de movimientos que garanticen el éxito en la proyección y recomendaciones sobre la utilización del feedback.O objectivo desta investigação é implementar a análise e detecção de estruturas temporais dos acontecimentos desportivos, ou padrões temporais (Padrões-T), para detectar erros técnicos e as suas sequências comportamentais na projecção do judo kosoto-gari e assim sugerir mudanças metodológicas nos processos de ensino do judo. Os participantes (n = 50; 38 homens e 12 mulheres; M = 19.23 anos; DP = 1.12), estudantes do grau em CAFE sem experiência prévia no judo, submeteram-se, a partir de um estudo observacional sistemático, a um registo em vídeo da execução da técnica em estudo. Os resultados, determinados mediante estatística descritiva e análise sequencial de Padrões-T obtidos com o programa Theme 5, corroboram a existência de uma série de erros típicos que os sujeito cometem na aprendizagem desta projecção, assim como uma sequência de erros em cadeia, que basicamente afectam o desequilíbrio, a posição dos pés e do tronco, a incorrecta acção de pega e a acção final dos braços. Estes resultados permitem-nos propor, na aprendizagem do judo, sequências de movimentos que garantam o êxito na projecção e recomendações sobre a utilização do feedback

III-V semiconductor quantum dots for efficient quantum light sources

Comunicación presentada en el 3rd international Workshop Engineering of quantum emitter properties, celebrado en Linz (Austria) el 17 y 18 de diciembre de 2015.Photonic crystal microcavities (PCMs) with embedded quantum dots (QDs) have been shown as excellent test bed systems for experiments in the field of cavity quantum electrodynamics (c-QED) that may open doors to efficient quantum photonic devices for the generation of single-photons, entangled photon pairs and ultra-low threshold lasing. Based on fundamental excitonic emission and on biexciton-exciton recombination cascade, a single QD embedded in a PCM become efficient emitters of single photons or entangled photon pairs provided that both spectral and spatial matching of the optical cavity mode and the optical emission of the single nanostructure occur. Within this approach, we have explored several systems and growth methods with the aim of fabricating QD which fulfil the requirements for an efficient coupling between a single QD and a PCM. We have fabricated QD by molecular beam epitaxy (MBE) using a) droplet epitaxy and b) selective nucleation at nano-holes fabricated by atomic force microscopy local oxidation (AFMLO) lithography. Results will be presented of QD in GaAs/AlGaAs(111)A, InAs/GaAs(001) and InAs/InP (001). With the aim of obtaining coupled QD-PCM, we have followed two procedures: one is based on the fabrication of a PCM around a buried QD whose position and wavelength emission are previously determined; the other approach consists of locating a single QD by using AFMLO, at the maximum of the electric field of a prefabricated PCM. A MBE re-growth procedure has been developed for completing the PCM membrane thickness.Peer Reviewe

Impressão 3D no ajuste dos móveis à antropometria dos alunos

Introducción: El alumnado universitario está una parte considerable de su día sentado, una falta de correspondencia entre las medidas antropométricas del alumnado y las dimensiones del mobiliario de la Facultad, puede tener efectos negativos posturales y académicos. La impresión 3D es una tecnología de fabricación por adición mediante las cual se puede crear un objeto tridimensional, en nuestro podría ser crear piezas para adaptar la altura del mobiliario existente. Objetivos: analizar el grado de ajuste del mobiliario de la Universidad de Vigo a las características antropométricas de su alumnado y buscar soluciones al grado de desajuste por medio de la impresión 3D. Métodos: En la investigación participaron 50 estudiantes universitarios (12 mujeres y 38 hombres). Se realizaron las mediciones de altura poplítea, altura del codo y del hombro sentado, con un antropómetro, para calcular su altura de mobiliario ideal y posteriormente compararlos con el mobiliario que utilizan en clase. Resultados y discusión: Los resultados muestran que para el 50% del alumnado, la silla está dentro de los parámetros ideales. Mientras que el 14% utiliza un modelo de mesa que coincide con sus medidas ideales. La impresión 3D permitiría dar una solución al ajuste del 52% de estudiantes que necesitan una silla más alta. Conclusiones: Existe un desajuste entre las características antropométricas del alumnado y el mobiliario que utilizan. La impresión 3D, es una tecnología a tener en cuenta en la búsqueda de soluciones de ajuste antropométrico.Abstract: Introduction: The university students are a considerable part of their day sitting, a lack of correspondence between the anthropometric measurements of the students and the dimensions of the furniture of the Faculty, can have negative postural and academic effects. 3D printing is an addition manufacturing technology through which a three-dimensional object can be created, in our case it could be creating pieces to adapt the height of the existing furniture. Aim: to analyze the degree of adjustment of the furniture of the University of Vigo to the anthropometric characteristics of its students and to find solutions to the degree of mismatch through 3D printing. Methods: 50 university students (12 women and 38 men) participated in the research. Popliteal height, elbow height and sitting shoulder measurements were made with an anthropometer to calculate their ideal furniture height and then compare them with the furniture they use in class. Results & discussion: The results show that for 50% of the students, the chair is within the ideal parameters. While 14% use a table model that matches their ideal measurements. 3D printing would provide a solution to the adjustment of 52% of students who need a higher seat. Conclusions: There is a mismatch between the anthropometric characteristics of the students and the furniture they use. 3D printing is a technology to consider when looking for anthropometric adjustment solutions.Resumo: Introdução: Os estudantes universitários são uma parte considerável do seu dia sentado, a falta de correspondência entre as medidas antropométricas dos alunos e as dimensões dos móveis da Faculdade, pode ter efeitos posturais e acadêmicos negativos. A impressão 3D é uma tecnologia adicional de fabricação através da qual um objeto tridimensional pode ser criado; no nosso caso, poderia estar criando peças para adaptar a altura dos móveis existentes. Objectivos: analisar o grau de adaptação dos móveis da Universidade de Vigo às características antropométricas de seus alunos e encontrar soluções para o grau de incompatibilidade através da impressão 3D. Métodos: 50 estudantes universitários (12 mulheres e 38 homens) participaram da pesquisa. As medidas de altura poplítea, altura do cotovelo e ombro sentado foram feitas com um antropômetro para calcular a altura ideal dos móveis e compará-las com os móveis usados nas aulas. Resultados e discussão: Os resultados mostram que para 50% dos alunos, a cadeira está dentro dos parâmetros ideais. Enquanto 14% usam um modelo de tabela que corresponde às suas medidas ideais. A impressão 3D forneceria uma solução para o ajuste de 52% dos estudantes que precisam de um assento mais alto. Conclusões: Há uma incompatibilidade entre as características antropométricas dos alunos e os móveis que eles usam. A impressão 3D é uma tecnologia a considerar ao procurar soluções de ajuste antropométrico

Design of a management methodology for building projects under a modular system in the Smartbrix company

Aunque la gestión de proyectos se conoce desde tiempos inmemorables, las metodologías en gestión de proyectos son una materia que se ha empezado a estudiar y a profundizar hasta hace relativamente poco. En un proceso paulatino de madurez, las organizaciones van entendiendo poco a poco que adoptar una metodología propia y ajustada a la naturaleza de los proyectos que desarrolla se convierte en un factor de éxito que se refleja en sus balances financieros. El presente trabajo tiene como objetivo principal, precisamente, diseñar una metodología de gestión de proyectos de edificación bajo sistema modular en la empresa SmartBrix. Dicha empresa cuyo espíritu es el desarrollo de proyectos de construcción con tecnología modular ha experimentado una gran variabilidad de diferentes resultados tanto positivos como negativos en el desarrollo de estos proyectos. Con este trabajo se pretende que, a través de una metodología diseñada a la empresa que recoge varios aspectos de estándares internacionalmente conocidos como ISO 21500, PMBOK, y PRINCE2, la variabilidad de dichos episodios disminuya y de esta forma la empresa pueda proyectar de mejor forma el éxito en la mayoría de los proyectos en los que esté envuelta. Para el diseño de la metodología se realizan encuestas a grupos focales dentro de la organización cuyos resultados arrojan una impresión clara de las fortalezas y puntos por mejorar que tiene la organización en su gestión actual de proyectos. Una vez determinadas estas características, se diseña una metodología la cual esta basada en estándares conocidos del PMI e ISO básicamente que fortalezca las virtudes que tienen y que a su vez corrija falencias o desacuerdos que se encuentren. Una vez diseñada la metodología, se ha desarrolla un plan inicial de implementación donde se revisan ajustes necesarios y practicidad de los procesos de la metodología en un periodo de tiempo de 3 meses con el fin que la empresa no solo reciba un modelo ajustado, sino que también un plan de aplicación que se irá acoplando de forma que no interrumpa sus operaciones diarias.Although project management has been known since very long time, project management methodologies are a subject that has been studied and deepened in this knowledge just recently. In a gradual process of maturity, organizations gradually understand that through adopting their own methodology and adjusted to the nature of the projects, they develop becomes a success factor that is reflected in their financial balance sheets. The main objective of this work is, precisely, to design a methodology for the management of building projects under a modular system in the SmartBrix company. This company whose spirit is the development of construction projects with a modular technology has experienced a great variability of different results, both positive and negative in the development of these projects. With this work it is intended that, through a methodology designed for the company that includes various aspects of internationally known standards such as ISO 21500, PMBOK and PRINCE2, the variability of said episodes decreases and in this way the company can improve its success in most of the projects in which it is involved. For the design of the methodology, surveys are carried out to focus groups within the organization, the results of which, give a clear impression of the strengths and points for improvement that the organization has in its current project management. Once these characteristics are determined, a methodology is designed which is based on known PMI and ISO standards that basically strengthens the virtues they have and which in turn corrects any shortcomings or disagreements that are found. Once the methodology has been designed, an initial implementation plan has been developed where necessary adjustments and practicality of the methodology processes are reviewed in a period of 3 months so that the company not only receives an adjusted model, but also an implementation plan that will be gradually coupled so that it does not interrupt or affect its daily operations.Magíster en Gerencia de ProyectosMaestrí

Match analysis and probability of winning a point in elite men’s singles tennis

Notational analysis and new technologies have allowed a better understanding of tactical actions in tennis. In particular, the combined analysis of different variables affecting performance is necessary to understand the relationships between actions in competition. The aim of this research was to analyse the probability of winning a point in men’s professional tennis based on the most relevant variables affecting performance in this sport. A total of 4,669 points were analysed on three different court surfaces from the final rounds (from the quarter-finals onwards) of three of the four Grand Slam tournaments in the 2021 season. An observational methodology was applied. Different analysis techniques were used to obtain the results: descriptive and chi-square with a significance level of p <0.05. First serve effectiveness (point won) was 69% on clay, 75% on grass and 75% on hard court. Second serve effectiveness (point won) was around 55% regardless of the surface. The majority of points, between 65% and 77% depending on the court surface, ended with a short rally (between one and four shots). Approximately 80% of the points played with first serve and short rally were won by the serving player. With first serve and medium length rallies, the probability of winning the point is similar between server (range 49–55%) and receiver on any court surface. The study reveals a set of patterns (based on the combination of information from the variables analysed) that determine the probability of winning a point. Descriptive data from this research could help coaches and players on match strategy at the highest levels of elite men’s single tennis