Design and optimisation of the architecture and the orientation of utility-scale photovoltaic power plants

The Spanish and European photovoltaic markets are set for a revival: massive GW deployments are expected in the coming years. Large utility-scale PV will increasingly take a role as baseload power plants, displacing dirtier sources of energy. PV project developers will need to optimise their design practices so as to achieve the most cost-effective solutions possible. For all these reasons, the present work is focused on the development of utility-scale PV plants in the Spanish context. A MATLAB based programme to simulate PV plants (developed by a former MSc Thesis student) has been improved and updated with new models, databases and performance indicators. Three main new models have been added to the original code: tracking system model, self-shading model and battery model. The updated MATLAB programme has been used to simulate a 100 MWp PV plant in Seville, Spain. Several relevant topics have been studied: the selection between string and central inverters and their DC/AC ratio; the effect of including trackers; the effect of self-shading losses on land-use; and the inclusion of a battery to provide flat-output response. Central inverters are found to be still more cost-effective, but string inverters follow the pace. DC/AC inverter ratios are concluded to be a fundamental designing choice impacting both performance and cost. Tracker devices are found to be highly competitive solutions (depending on the location), but a more careful study on land-use will be required in future works. A compromise in performance have been found between self-shading losses and land-use: reducing land-use reduces considerably the energy yield, thus row spacing and module configuration are fundamental design choices. Batteries providing services to the grid will play a key role in renewable energy integration, such as the flat-output response studied. However, further battery cost reductions or government incentives are required to make these projects more profitable. The PV industry and policy regulators must work together to ensure a sustainable development of the European and Spanish utility-scale PV sectors, with PV developers enhancing and refining their design best practices

Flame-Wall Interactions at Elevated Pressure Studied with Advanced Laser Diagnostics

Despite the ongoing progress in electrification driven by the indispensable substitution of fossil fuels with renewable energy sources, the thermochemical conversion of chemical energy carriers is expected to continue playing an important role in the energy transition. This underlines the necessity for continual development of low-emission combustion technologies, grounded in a comprehensive understanding of the underlying physical processes through ongoing fundamental research efforts. Within this cumulative dissertation, the complex phenomenon of flame-wall interaction (FWI), which is an essential aspect of practical combustion systems, is investigated experimentally using advanced laser diagnostics. FWI involves the mutual interaction between chemical reaction, solid surface and fluid flow and is associated with undesired effects, such as reduced efficiency and increased pollutant emissions. The main objective of this thesis, which includes three peer-reviewed publications, is the investigation of fundamental aspects of FWI at elevated pressures and increased Reynolds numbers, mimicking operating conditions of practical combustion systems. Experiments are carried out within a novel, enclosed test rig - the pressurized side-wall quenching (SWQ) burner - which provides a reproducible, generic configuration of a premixed flame interacting with a cold, solid wall. This test rig was designed, built and commissioned within the scope of this thesis and is presented in detail. The process under investigation is examined at operating pressures ranging between atmospheric and 5 bar absolute and Reynolds numbers up to 20,000 using various laser diagnostics. Limitations of such measurement techniques resulting from the complex test rig design and process-inherent challenges arising with increasing pressure are reported. First, a characterization of the turbulent flow field and the combustion dynamics is conducted using velocity data and spatial fields of the instantaneous flame front positions, provided by high-speed and low-speed particle image velocimetry measurements and planar, laser-induced fluorescence of the hydroxyl radical (OH-PLIF). This involves the inspection of the inflow and the near-wall flow field under non-reacting and reacting conditions, as well as the examination of the transient flame front motion. Building on this, turbulent flame propagation close to the wall is further analyzed in terms of the flame surface density (FSD), a central quantity in numerical combustion modeling, which is derived from measured flame front positions (OH-PLIF) following two common approaches. Furthermore, the near-wall thermochemistry of the turbulent flame quenching process is explored through simultaneous measurements of the gas-phase temperature and mole fractions of CO2 and CO by means of dual-pump coherent anti-Stokes Raman spectroscopy and laser-induced fluorescence of CO. These measurements represent the first reported attempt to investigate the thermochemistry of FWI at pressures above atmospheric by means of multi-parameter laser diagnostics. This cumulative dissertation presents novel insights into the impact of elevated pressure and increased Reynolds numbers on turbulent FWI and provides experimental data for model validation. It furthermore, contributes to the FWI research community by exploring the limits of state-of-the-art laser diagnostics for measurements in pressurized, near-wall reactive flows

Pending issues from digital inclusion in Ecuador: challenges for public policies, programs and projects developed and ICT-mediated teacher training

The policies of digital inclusion in Ecuador had a rebound since 2007, placing technology as a priority axis for government management. Despite this, there are still pending issues to be developed. This study is based on a qualitative approach that, through documentary research, bibliographic analysis and critical review of literature, can generate contributions that allow the identification of challenges and possible gaps to be faced by government entities in Ecuador when proposing actions that link education and technology. As main findings, it can be mentioned that the impacts and results from the application of the National Development Plans must transcend the figures, which allow to deepen the analysis in relation to this topic, together with initiatives and proposals that regarding digital inclusion cannot be developed in isolation and need to have comprehensive long-term management. Finally, it is essential to understand that it is not necessary to create only platforms, it is relevant to work from integral pedagogical designs that start by understanding teachers from their experiences, accompaniment and motivation for the design of a contextualized training structure on digital mediation issues

Design of a mooring system for a Wave Energy Converter

In the current scenario of exhaustion of fossil fuels, new forms of alternative energy must gain ground. Taking advantage of the great amount of water, the element that gives name to our planet (blue planet); this thesis is focused on one of the ways to extract energy from water: using the waves motion in order to generate electricity. The aim of this thesis is to collaborate in a project of a Wave Energy Converter developed by a group of researchers of Politecnico di Torino. Specifically, much of the study will focus on the design a mooring system for the Wave Energy Converter and integrate it to the linear model of the system. First of all, in the first chapter an overview of the energy consumption problem is given. It is also commented the need of using renewable sources and some of them are presented. In chapter two, it is presented the wave power as a possible clean energy source. It is also explained with numerical values the great viability of this source both globally and in Europe. Finally, some sea characteristics of the region where the Wave Energy Converter will be placed (Mediterranean Sea, Pantelleria) are also commented. Then in chapter three, the concept of a Wave Energy Converter is described. Two different ways to classify these devices are given and some existent Wave Energy Converters projects are presented. In chapter four it is presented the Wave Energy Converter studied in this thesis: the PEWEC (PEndulum Wave Energy Converter). Its working principle it is briefly remarked and some aspects of the mechanism that makes the energy conversion (the pendulum) are commented. Chapter five is focused on one of the main goals of this thesis: the mooring system. Firstly, a presentation of the objectives, requirements, different configurations and components of a mooring system is given. Then, the PEWEC’s mooring system is described: its design, the integration of the mooring system into the PEWEC’s linear model and the obtaining of the mooring stiffness and parameters. In chapter six, the 1:45 PEWEC prototype is fully described. Its components are named and are explained. This work is done by comparing the SolidWorks drawings with real images of the prototype. Chapter seven is focused on the description of the PEWEC’s linear model. It will be commented its parameters and the linear model will be launched. The results of the simulation will be presented and analyzed. In order to facilitate the analysis, a graphic data analysis will be developed. Then in chapter eight, the tests carried out in Rome with the 1:45 prototype are explained. The testing facilities and the different tests developed are described and the data collected is analyzed. In chapter nine, it will be possible to develop a first comparison between the linear model simulation and the testing results. Finally, the last part consists in a conclusion of all the work developed in this thesis. It will be possible to extract some conclusions about the comparison between the linear model and the testing results. At the end of this document it is possible to find an annex with extra information of the work developed, such as parts of Matlab code. It is important to comment that this thesis is focused in the 1:45 prototype. However, in parallel it has been developing the 1:12 prototype. The 1:12 prototype is expected to be tested during July 2015. All the study developed in the mooring system for the 1:45 prototype can also be useful for the 1:12 prototype, with a necessary adaptation of the parameters

Plan de comunicación digital para el Instituto Ecuatoriano de Crédito Educativo y Becas, IECE

La finalidad de esta tesis es elaborar un plan de comunicación digital para el Instituto Ecuatoriano de Crédito Educativo y Becas (IECE), destinado a constituirse en el complemento del plan general de marketing; su fin es concebir las actividades de comunicación y de publicidad online, que deberán realizarse en el transcurso del año, para que estas respondan a una estrategia destinada a fortalecer e incrementar los canales digitales empleados, a través de los cuales se promueva la marca, los servicios y la interacción con los usuarios reales y potenciales. Se inicia señalando una reseña histórica del IECE, que describe los acontecimientos más importantes por los que atravesó, a continuación se efectúa una descripción de la Institución, especificando los productos y servicios que proporciona. Se establece el marco teórico, en primera instancia se menciona la historia de internet, para a continuación establecer los conceptos de marketing digital que sustentan el presente trabajo. Luego se procede a efectuar la evaluación situacional, partiendo con el análisis interno, a través de la cadena de valor; seguidamente se realiza el análisis externo; mediante el estudio del microentorno, en el cual se lleva a cabo una investigación de mercado y se evalúa a la competidores directos, potenciales, así como los productos sustitutos; además del estudio del macroentorno y las dimensiones que lo conforman. Elementos que sirvieron para determinar la situación competitiva y el atractivo del entorno. Finalmente se procede a la estructuración del plan, partiendo con la definición de los objetivos y del posicionamiento deseado; siguiendo con la formulación de estrategias, en las que se establece las acciones que se realizarán y las herramientas digitales que se utilizarán, con su correspondiente presupuesto; incorporando además un plan de acción. Finalmente se cierra con las conclusiones y recomendaciones

Uniones estructurales de bambú: criterios de su desempeño a partir de ensayos.

The first bamboo construction standards were published at the beginning of this century, so they cannot be considered finished. Within them, the connections, due to their extreme complexity, constitute poorly defined elements and are a challenge for structural design. This, together with the physical characteristics of bamboo, that is, its high variability, presence of hollow culms, non-uniform curved section along its entire length, not perfectly straight and relatively small in thickness, increase the difficulty of the calculation and make it necessary use designs that achieve strength and safety. For this reason, an integrative review of published research was carried out, based on structural tests with different types of these joints. The objective was to determine the types of connections that offer the best structural performance according to the test results, identify the main elements that contribute to their failure and issue design considerations that allow increasing their resistance and durability. The bibliographic search covered 287 documents, using pairs of keywords. The 12 original articles that showed tests carried out with these connections were selected. The results indicated the need to use reinforced connections, without drillings or cuts in the culm, but the use of clamps, which allow flexible and simple designs. The studies published from the performance of tests on bamboo joints are scarce, so it is essential to develop research of this type that provides practical and reliable tools to professionals who work with these systems.Las primeras normas de construcción con bambú se publicaron a inicios del presente siglo, por lo que no pueden considerarse acabadas. Dentro de ellas, las conexiones, por su extrema complejidad, constituyen elementos poco definidos y son un reto para el diseño estructural. Esto, unido a las características físicas del bambú, es decir, su alta variabilidad, presencia de culmos huecos, de sección curva no uniforme en toda su longitud, no perfectamente rectos y de espesor relativamente pequeño, incrementan la dificultad para el cálculo y hace necesario utilizar diseños que logren resistencia y seguridad. Por ello se realizó una revisión integrativa de investigaciones publicadas, basadas en ensayos estructurales con diferentes tipos de estas uniones. El objetivo fue determinar los tipos de conexiones que ofrecen mejor desempeño estructural según los resultados de ensayos, identificar los principales elementos que contribuyen a su fallo y emitir consideraciones de diseño que permitan incrementar su resistencia y durabilidad. La búsqueda bibliográfica abarcó 287 documentos, utilizando pares de palabras clave. Se seleccionaron los 12 artículos originales que mostraron ensayos realizados con dichas conexiones. Los resultados indicaron la necesidad de utilizar conexiones reforzadas, sin perforaciones ni cortes en el culmo, a través del uso de abrazaderas, que permiten diseños flexibles y sencillos. Los estudios publicados a partir de la realización de ensayos en uniones de bambú son escasos, por lo que es imprescindible el desarrollo de investigaciones de este tipo que provean de herramientas prácticas y confiables a los profesionales que trabajan con estos sistemas

Gestión curricular para favorecer la aplicación de estrategias en los docentes para la solución de problemas en el área de matemática en la Institución Educativa N° 32011 Hermilio Valdizán de Huánuco

El estudio de investigación acción cuyo objetivo es aplicar un plan de gestión curricular para favorecer la aplicación de estrategias en los docentes para la solución de problemas en el área de matemática en la institución educativa N° 32011 Hermilio Valdizán de Huánuco. El plan de investigación acción tiene como principales actores al cuerpo directivo (director, subdirector), los beneficiarios directos son 40 docentes de aula y los beneficiarios indirectos son 1200 estudiantes distribuidos del primer al sexto grado. Desde el punto de vista del diseño de estudio es Investigación Acción Participativa. Según Roberts, como se citó en Hernández et al (2014, p 501) “En estos diseños se resuelven una problemática o implementan cambios, pero en ello intervienen de manera más colaborativa y democrática uno o varios investigadores y participantes o miembros de la comunidad involucrada”. Para el proceso de recojo de la información se utilizó la técnica grupos de discusión y su instrumento guía de discusión, cuya información permitió conocer los principales hallazgos que se han priorizado como dimensiones de estudio. Luego de ejecutar el plan de acción se procesará la información que nos conllevará a conclusiones significativas en la práctica docente.Tesis de segunda especialida

On the evolution of turbulent boundary layers during flame-wall interaction investigated by highly resolved laser diagnostics

The turbulent boundary layer behavior in the presence of flame-wall interactions (FWI) has an important role on the mass and energy transfer at the gas/solid interface. Detailed experiments resolving the turbulent boundary layer evolution in the presence of FWI are lacking, which impedes knowledge. This work presents a combination of particle image velocimetry (flow field), dual-pump coherent anti-Stokes Raman spectroscopy (gas temperature), and OH laser induced fluorescence (flame topology) measurements to study the evolution of the boundary layer structure in the presence of FWI. Experiments are conducted in a side-wall quenching (SWQ) burner. Findings reveal that the reacting boundary layer flow adheres to the linear scaling law u+ = y+ in the viscous sublayer until y+ = 5. Beyond y+ = 5, the flame modifies the velocity and temperature field such that the uz+ streamwise velocity deviates from the viscous sublayer and the law-of-the-wall scaling in the log-layer with uz+ being smaller than that of the non-reacting flow (the subscript z refers to the streamwise coordinate and is used throughout this manuscript). As the fluid approaches the flame impingement location at the wall, the gas temperature increases significantly, causing a threefold increase in kinematic viscosity, ν. Although the near-wall streamwise velocity gradient d&lt;Uz&gt;/dy|y=0 decreases, the larger increase in ν reduces uz+ and leads to the deviation from the law-of-the-wall. Downstream the flame impingement location, ν is relatively constant and uz+ values begin to approach those of the law-of-the-wall. Trends are presented for SWQ and head-on quenching flame topologies, and are intended to help development of more accurate wall models.  </div

Under pressure: An analysis of the perceived positioning pressure on socio-political issues and its influence on the external communication of German companies

Today, more and more companies tend to position themselves with public statements on socio-political issues such as racism or discrimination against the LGBTQIA+ community represented through popular movements like Black Lives Matter or the Pride Month. According to surveys, most consumers expect companies to take a stand on such polarizing topics. Despite this apparent relevance in society, there is only little research on companies taking public stances, yet. Moreover, the existing studies addressing the topic predominantly focus on the influence of corporate positioning on customer attitudes and only a few studies examine the impact of companies speaking out on socio-political issues, their communication and decision-making processes, and their attitudes. In order to close this research gap, 19 semistructured interviews with communicators of internationally operating German B2C companies were conducted. As the results show, the interviewed companies are all perceiving societal pressure, but up to different degrees. Equally different is the associated impact of positioning on external communications and strategic planning. In general, three initial patterns can be identified on how companies deal with positioning pressure: The skeptics, who do none or almost no positioning, the adapters, who speak out on specific issues and closely observe the current debates, and the pioneers, who feel less pressure and are the first companies to speak out and even initiate debates themselves. It remains to be seen if these patterns will be established in future research and if uniform strategies in corporate communications will develop when it comes to the topic of socio-political positioning