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Concentrating Solar Power systems are widely applied as a means to utilize the sun's abundant renewable energy, but the design of these processes facilitates the occurrence of overheating. This work presents two approaches for calculating the mirror angles of a fresnel collector in order to limit the amount of solar energy collected. The proposed structures are designed to receive a desired focus value from a controller and generate references for the mirror inclination controllers of the collector. The first strategy consists of the use of an optimization problem coupled with a simplified model of the collector. Whereas, the second approach consists of an ANFIS network that is trained with data from a reliable collector model made in SolTrace®. Both approaches are compared with simulations in SolTrace® the results show that the ANFIS solution presented overall better results, taking into account error and computational time.

In the near future, next-generation telescopes will be able to observe Earth-like exoplanets illuminated by their parent stars for long periods of time. As the distance between exoplanet and observer is enormous, exoplanets will only make up a pixel on our image. However, the observed intensity of this pixel will fluctuate over time as the exoplanet rotates about its axis and orbits around its parent star. These fluctuations in the reflected light contain information about the planet’s surface. Previous researchers have developed a retrieval method known as spin-orbit tomography which uses these intensity fluctuations to construct a surface map of the exoplanet assuming fully diffuse reflection as a model for the reflection of starlight. In this thesis, we aim to build on this method by introducing two new reflection models, namely Fresnel and Lommel-Seeliger reflection, and by using this composite reflection model for the starlight we attempt to reconstruct the surfaces of exoplanets based on their observed light curve. We will derive an analytical expression for the observed intensity of the light reflected off an exoplanet. Next, we will simulate intensity observations along the orbit of an exoplanet with a pseudo-randomly generated surface containing terrain types found on Earth. As we assign a measure of reflectance for each reflection model, we will construct three distinct reflectance maps for one planet, nd simulate the observed light curve by linearly transforming these maps. Afterward, we attempt to retrieve the reflectance maps from the observed signal by inverting the transformation. We show that the retrieval of all three maps is successful if the light curve is observed without noise, even when the number of samples is low. If artificial shot noise is imposed on our signal, we are still able to retrieve glossy reflectance maps for Lambertian and Lommel-Seeliger reflection by truncating the transformation matrix. Lastly, we show that even if the

With the advancement of new technologies, power systems are increasingly equipped with more sensors and actuators, heightening the risk of failure. This fact, together with the vulnerability of solar plants -not only to internal faults but also to the action of the sun, rain, wind, and animals, among others- gives rise to the need for detecting and identifying faults to deal with them. Methods that detect and diagnose faults play a crucial role in solar plants, allowing the systems to cope with them as soon as they occur and before they lead to large-scale problems. This work proposes using neural networks to detect and distinguish mirror and flow rate faults in a Fresnel plant. In addition, a defocusing stage is added to access hard-to-isolate faults, increasing the accuracy of 89.61% to 97.43%. These results contribute to the problem of isolability in thermal solar plants. The simulations for obtaining the neural networks and the results were conducted on a model of the Fresnel plant located at the Engineering School of Seville, Spain (ETSI).

Una placa zonal de Fresnel és un dispositiu bidimensional que té una funcionalitat similar a una lent convergent. Una de les seves aplicacions és la utilització com a objectiu fotogràfic. Aquest projecte té el plantejament de valorar opcions fotogràfiques alternatives a les tradicionals d’aquest moment. Els objectius convencionals es manufacturen pul·lint lents de vidre i integrant-les mecànicament en una montura. Una alternativa és utilitzar la difracció per comptes de la refracció com a mètode per dirigir la llum cap al pla focal. Això permet utilitzar com a objectiu estructures en dues dimensions, que es poden realitzar de manera fotogràfica o litogràfica i que tenen l’avantatge de ser més lleugeres i menys voluminoses. Val a dir, que els objectius que funcionen en base a la refracció també poden ser útils per fotografiar en longituds d’ona a les quals el vidre és opac (per exemple UV) o no té poder refractiu (per exemple raigs X). Aquest treball també preten exposar una representació artística del resultat aconseguit i fer una exploració de les possibilitats en aquest sentit. Les imatges obtingudes amb mètodes difractius tenen les seves pròpies caracterìstiques degut a que la imatge d’un punt serà, encara més que en els objectius convencionals, un patró de difracció i això tindrà un efecte distintiu a les imatges.

In this Letter, we present a method for chromatic compensation in numerical reconstruction of digitally recorded holograms based on Fresnel-Bluestein propagation. The proposed technique is applied to correct the chromatic aberration that arises in the reconstruction of RGB holograms of both millimeter-and micrometer-sized objects. The results show the feasibility of this strategy to remove the wavelength dependence of the size of the numerically propagated wavefields. (C) 2017 Optical Society of America

CubeSats are no longer just an academic exercise, but they have become a commercial and technical solution in the space field. Improvements in miniaturization, electronics and energy have made it possible to reduce the dimensions of the spacecraft, and therefore, their antennas size. This document shows first the design and simulation of a deployable Fresnel Zone Plate type antenna. In a second stage, the manufacturing and testing is presented in two ways, using two configurations: a heavier and more robust one with a paint-based conductor and a lighter one with a silver adhesive tape-based conductor. Both results are positive, the second one being especially satisfactory and leading to subsequent studies that further improve the system.

One of the ways to improve the efficiency of solar energy plants is by using advanced control and optimization algorithms. In particular, model predictive control strategies have been applied successfully in their control. The control objective of this kind of plant is to regulate the solar field outlet temperature around a desired set-point. Due to the highly nonlinear dynamics of these plants, a simple linear controller with fixed parameters is not able to cope with the changing dynamics and the multiple disturbance sources affecting the field. In this paper, an adaptative model predictive control strategy is designed for a Fresnel collector field belonging to the solar cooling plant installed at the Escuela Superior de Ingenieros in Sevilla. The controller changes the linear model used to predict the future evolution of the system with respect to the operating point. Since only the inlet and outlet temperatures of the heat transfer fluid are measurable, the intermediate temperatures have to be estimated. An unscented Kalman filter is used as a state estimator. It estimates metal-fluid temperature profiles and effective solar radiation. Simulation results are provided comparing the proposed strategy with a PID + feedforward series controller showing better performance. The controller is also compared to a gain scheduling generalized predictive controller (GS-GPC) which has previously been tested at the actual plant with a very good performance. The proposed strategy outperforms these two strategies. Furthermore, two real tests are presented. These tests show that the proposed controller achieves adequate set-point tracking in spite of strong disturbances.

El objetivo de este trabajo es describir el diseño y desarrollo de un concentrador lineal de Fresnel que pueda concentrar las radiaciones solares hacia un tubo receptor con una relación de concentración de 11,54. La metodología aplicada permitió analizar el espaciado, las inclinaciones y los anchos adecuados de los espejos más convenientes para obtener el mayor factor de concentración solar y las pérdidas ópticas y térmicas mínimas. El diseño del colector de concentración solar consistió en un sistema de 3.5 m x 3.0 m x 2.65 m con 15 espejos, cada uno de 0.12 m de ancho, y una altura central de recepción de 2.0 m. Los resultados experimentales confirmaron que se alcanzó la temperatura máxima del proceso 140 °C. Además, el almacenamiento de aceite térmico fue de 995 kJ-h disponibles en 6 horas (desde las 9: 00h hasta las 15: 00h). Las pruebas de rendimiento del sistema se realizaron en la ciudad de Barranquilla, con las condiciones ambientales locales. Las pruebas experimentales del prototipo permitieron validar el diseño propuesto en este trabajo., The goal of this work is to describes the design and development of a fresnel linear concentrator that be able to concentrate sun radiations towards a receiver tube with a concentration ratio of 11, 54. The methodology applied allowed to analysis the spacing, the inclinations and the adequate widths of the mirrors that would be more convenient to obtain the highest solar concentration factor and the minimum optical and thermal losses. The design of the solar concentration collector consisted of a 3.5 m x 3.0 m x 2.65 m system with 15 mirrors, each one measuring 0.12 m wide, and a receiving center height of 2.0 m. The experimental results confirmed that the maximum process temperature of 140 ° C was achieved. In addition, a thermal oil storing was 995 kJ-h available in a 6-hour (since 9:00h until 15:00h). The performance tests of the system were performed in the city of Barranquilla, with local environmental conditions. The experimental tests of the prototype finally allowed to validate the design proposed in this present work.

En este proyecto se ha realizado un estudio acerca de las lentes Fresnel y su posible aplicación en el entorno de la medicina mediante el uso de ondas de ultrasonido. Este trabajo empieza con un desarrollo teórico de las ecuaciones que definen el comportamiento de lentes Fresnel ante ondas esféricas y el posterior diseño de las características de la lente utilizada a lo largo del proyecto. Seguidamente, también se han realizado simulaciones para demostrar el correcto funcionamiento del experimento y desarrollar un sistema de configuración del patrón de focalización en lentes de ultrasonidos. Finalmente, con la ayuda de un sistema acuático robotizado diseñado en el laboratorio de Física de la ETSIT y diversos transductores, se han realizado distintas medidas para tratar de demostrar experimentalmente la eficacia de nuestra idea. A lo largo de los tres bloques claramente diferenciados: modelo teórico, simulaciones y experimentos, ha sido necesario aplicar diversos conceptos relacionados con el procesado de señal y diseño de aplicaciones mediante Matlab, control remoto de instrumentos electrónicos, y uso de Comsol Multiphysics. A aquest projecte s'ha realitzat un estudi sobre les lents Fresnel i la seua possible aplicació en l'entorn de la medicina mitjançant l'ús d'ones d'ultrasò. Aquest treball comença amb un desenvolupament teòric de les equacions que defineixen el comportament de lents Fresnel davant ones esfèriques i el posterior disseny de les característiques de la lent utilitzada al llarg del projecte. Seguidament, també s'han realitzat simulacions per demostrar el correcte funcionament de l'experiment i dissenyar un sistema de configuració del patró de focalització en lents d'ultrasò. Finalment, amb l'ajuda d'un sistema aquàtic robotitzat dissenyat al laboratori de Física de l'ETSIT i diversos transductors, s'han realitzat diferents mesures per intentar demostrar experimentalment l'eficàcia de la nostra idea. Al llarg dels tres blocs clarament diferenciats: mo, A study has been made about Fresnel lenses and their possible application in the field of medicine through the use of ultrasound waves. This work begins with a theoretical development of the equations that define the behavior of Fresnel lenses with spherical waves and the subsequent design of the characteristics of the lens used throughout the project. Moreover, simulations have also been carried out to demonstrate the correct functioning of the experiment and develop a configuration system of focalization patterns in ultrasonic lenses. Finally, using a robotic aquatic system designed in the ETSIT Physics laboratory and various transducers, different measures have been done to demonstrate experimentally the effectiveness of our idea. Throughout the three clearly differentiated blocks: theoretical model, simulations and experiments, it has been necessary to apply various concepts related to signal processing and Matlab application design, remote control of electronic instruments, and use of Comsol Multiphysics.

[EN] In this work, the distortion of the Fresnel Zone Plate focusing profile generated by a piston emitter in ultrasound applications is significantly reduced through the use of phase correction rings, which compensate the effect of the piston emitter radiation diagram. Both simulation and experimental results demonstrate the improvement achieved with this design method over the conventional case.

Fresnel reflection on a water surface is highly variable throughout the year and can have a significant influence on building-integrated vertical PV panels, yet is generally disregarded in yield calculations. We analyze beam irradiances of two horizontal pyranometers situated next to a lake, one facing upwards and one facing downwards, to estimate the contribution of Fresnel reflection to the beam irradiance on a vertical surface. We show that in general the observed beam irradiance on the downward facing instrument matches the calculated Fresnel reflection. In contrast to other studies investigating water albedo, we also found that the reflection percentage decreases consistently with higher wind speeds and lower solar zenith angle. Fresnel reflection has the highest contribution for vertical surfaces in winter, with varying contributions between 30% of monthly global irradiance over the course of one year for different latitudes, and should thus be included in yield estimates for building integrated PV installations situated next to bodies of water.

En este trabajo de fin de grado se analizan los diferentes tipos de colectores solares que hay en la industria, desde los modelos estacionarios sin concentración solar hasta los modelos más avanzados en concentración solar con seguimiento. Se describen las características técnicas y de operación del concentrador Fresnel situado en la Escuela de Ingenieros de Sevilla, además del planteamiento tanto del modelo detallado térmico y óptico, como su posterior modelo simplificado a partir de los datos recogidos usando el programa Matlab. Finalmente, se implementan los factores correctores por ángulo de incidencia y variación del caudal en el modelo simplificado y su posterior comparación con el modelo detallado en diferentes condiciones de operación.

Photonic crystals for LED

La difracción es el fenómeno que ocurre cuando las ondas se propagan y se encuentran con un obstáculo. Se trata de un aspecto fundamental en Óptica, ya que todos los sistemas ópticos están afectados por la difracción, produciendo en general dos efectos desfavorables. Por un lado produce un ensanchamiento de los haces a lo largo de su propagación. Por otro lado, limita el tamaño mínimo posible del haz al ser enfocado. A lo largo de los años, ha habido multitud de intentos de mejorar o reducir estos inconvenientes tanto en la difracción de campo lejano como también en la de campo cercano. En este artículo nos centraremos en el estudio de los límites impuestos por la difracción de campo lejano, y especialmente en el segundo problema que explicábamos antes: cómo mejorar el poder resolutivo o de una manera más general, la respuesta tridimensional de un sistema, ya que nosotros estamos especialmente interesados en sistemas ópticos como formadores de imagen. En segundo lugar mostraremos el uso de los moduladores espaciales de luz basados en cristal líquido (LC-SLM) para crear filtros de transmisión y/o fase no uniforme y también la generación de elementos ópticos difractivos orientados a formación de imagen. Mostraremos resultados experimentales que cubren un amplio abanico de posibilidades ofrecidas por el uso conjunto de los filtros mencionados y de los dispositivos LC-SLM.

[EN] We demonstrate the use of CCD image sensors and LCD screens from discarded electronic devices as elements for performing simple optical diffraction experiments. The experiments can determine the spatial structure of these components by analyzing diffraction patterns generated by their interaction with monochromatic light. This article presents the design and results of such experiments. (C) 2014 American Association of Physics Teachers.

Se ha desarrollado en este trabajo un conjunto de componentes de EcosimPro® para la simulación del captador tipo Fresnel de una planta solar situada en la Escuela Técnica Superior de Ingeniería de la Universidad de Sevilla. Se ha basado en un modelo de parámetros distribuidos, ajustando los parámetros del mismo con datos tomados del sistema real y comparando la respuesta del modelo con la temperatura de salida real del sistema.

En este artículo se presenta el modelado matemático, así como algoritmos de control de un captador solar tipo Fresnel que pertenece planta de refrigeración solar situada en la Escuela Superior de Ingenieros de la Universidad de Sevilla. Se va a desarrollar un modelo de parámetros distribuidos, ajustando los parámetros del mismo con datos tomados del sistema real y comparando la respuesta del modelo con la salida del sistema. Por último, se implementará una estrategia de control clásica, un PID con un compensador de perturbaciones de tipo feedforward paralelo, cuyo desempeño será validado mediante simulación usando el modelo de parámetros distribuidos.

Práce se zabývá základními přehledem, výhodami a možnostmi využití jednotlivých lamp a osvětlovací techniky. V kapitole o svícení ukazuje odlišnost videoklipového svícení, které se v mnoha faktorech blíží fotografickému svícení. Spolu s praktickými ukázkami poskytuje přehled o vhodnosti použití jednotlivých typů svícení pro dosažení potřebné atmosféry nebo efektu. Obsahuje praktické informace týkající se natáčení a výběru vhodné světelné výbavy pro natáčení., This work introduces the fundamentals of lighting and its effects. It helps to improve the quality level of produced videos, which are often created by authors with good ideas, but without sufficient knowledge of background. The chapter related to the review of individual lamps and accessories deals with the basic advantages and possibilities of each lamp for specific shooting conditions. In addition there are some recommendations from the practice work. The chapter "Basic types of lighting" shows the difference of lighting music videos, which is very close to photographic techniques of lighting followed by the practical examples. In the topic called "Filters'q text provides sufficient information about its properties, usage and the resulting effect of each filter. In conclusion part is written practical information concerning the shooting and the right selection of stuff for suitable locations for shooting., Ústav produktového designu, obhájeno

This course is an introduction to optical science with elementary engineering applications. Topics covered include geometrical optics: ray-tracing, aberrations, lens design, apertures and stops, radiometry and photometry; wave optics: basic electrodynamics, polarization, interference, wave-guiding, Fresnel and Faunhofer diffraction, image formation, resolution, and space-bandwidth product. Emphasis is on analytical and numerical tools used in optical design. Graduate students are required to complete additional assignments with stronger analytical content, and an advanced design project.

Tato bakalářská práce má za úkol předvést knihovnu OpenSceneGraph a její použití v kombinaci se shadery psanými v OpenGL Shading Language. Práce se nejdříve věnuje právě základům jazyka GLSL. Následující kapitola představí základy práce s knihovnou OpenSceneGraph. Další kapitoly se pak věnují postupně jednotlivým shaderům. Prvně je to vertex displacement mapping, po něm následuje cartooning a posledním shaderem je vodní hladina., This bachelor's thesis presents OpenSceneGraph library and its use with shaders written in OpenGL Shading Language. First of all it presents the basics of GLSL. Next chapter introduces the basics of OpenSceneGraph library. Following chapters are about different shaders. First is vertex displacement mapping, followed by cartooning and the last one is water surface.

Tato bakalářská práce má za úkol předvést knihovnu OpenSceneGraph a její použití v kombinaci se shadery psanými v OpenGL Shading Language. Práce se nejdříve věnuje právě základům jazyka GLSL. Následující kapitola představí základy práce s knihovnou OpenSceneGraph. Další kapitoly se pak věnují postupně jednotlivým shaderům. Prvně je to vertex displacement mapping, po něm následuje cartooning a posledním shaderem je vodní hladina., This bachelor's thesis presents OpenSceneGraph library and its use with shaders written in OpenGL Shading Language. First of all it presents the basics of GLSL. Next chapter introduces the basics of OpenSceneGraph library. Following chapters are about different shaders. First is vertex displacement mapping, followed by cartooning and the last one is water surface.

Tato bakalářská práce má za úkol předvést knihovnu OpenSceneGraph a její použití v kombinaci se shadery psanými v OpenGL Shading Language. Práce se nejdříve věnuje právě základům jazyka GLSL. Následující kapitola představí základy práce s knihovnou OpenSceneGraph. Další kapitoly se pak věnují postupně jednotlivým shaderům. Prvně je to vertex displacement mapping, po něm následuje cartooning a posledním shaderem je vodní hladina., This bachelor's thesis presents OpenSceneGraph library and its use with shaders written in OpenGL Shading Language. First of all it presents the basics of GLSL. Next chapter introduces the basics of OpenSceneGraph library. Following chapters are about different shaders. First is vertex displacement mapping, followed by cartooning and the last one is water surface.

Tato bakalářská práce má za úkol předvést knihovnu OpenSceneGraph a její použití v kombinaci se shadery psanými v OpenGL Shading Language. Práce se nejdříve věnuje právě základům jazyka GLSL. Následující kapitola představí základy práce s knihovnou OpenSceneGraph. Další kapitoly se pak věnují postupně jednotlivým shaderům. Prvně je to vertex displacement mapping, po něm následuje cartooning a posledním shaderem je vodní hladina., This bachelor's thesis presents OpenSceneGraph library and its use with shaders written in OpenGL Shading Language. First of all it presents the basics of GLSL. Next chapter introduces the basics of OpenSceneGraph library. Following chapters are about different shaders. First is vertex displacement mapping, followed by cartooning and the last one is water surface.

Tato bakalářská práce má za úkol předvést knihovnu OpenSceneGraph a její použití v kombinaci se shadery psanými v OpenGL Shading Language. Práce se nejdříve věnuje právě základům jazyka GLSL. Následující kapitola představí základy práce s knihovnou OpenSceneGraph. Další kapitoly se pak věnují postupně jednotlivým shaderům. Prvně je to vertex displacement mapping, po něm následuje cartooning a posledním shaderem je vodní hladina., This bachelor's thesis presents OpenSceneGraph library and its use with shaders written in OpenGL Shading Language. First of all it presents the basics of GLSL. Next chapter introduces the basics of OpenSceneGraph library. Following chapters are about different shaders. First is vertex displacement mapping, followed by cartooning and the last one is water surface.

SPIE OPTO, 2017, San Francisco, California, United States, Giichi Shibuya, Shohei Yamano, Hiroyuki Yoshida, and Masanori Ozaki "Active liquid-crystal deflector and lens with Fresnel structure", Proc. SPIE 10125, Emerging Liquid Crystal Technologies XII, 101250V (15 February 2017). DOI: https://doi.org/10.1117/12.2261113, A new type of tunable Fresnel deflector and lens composed of liquid crystal was developed. Combined structure of multiple interdigitated electrodes and the high-resistivity (HR) layer implements the saw-tooth distribution of electrical potential with only the planar surfaces of the transparent substrates. According to the numerical calculation and design, experimental devices were manufactured with the liquid crystal (LC) material sealed into the sandwiched flat glass plates of 0.7 mm thickness with rubbed alignment layers set to an anti-parallel configuration. Fabricated beam deflector with no moving parts shows the maximum tilt angle of ±1.3 deg which can apply for optical image stabilizer (OIS) of micro camera. We also discussed and verified their lens characteristics to be extended more advanced applications. Transparent interdigitated electrodes were concentrically aligned on the lens aperture with the insulator gaps under their boundary area. The diameter of the lens aperture was 30 mm and the total number of Fresnel zone was 100. Phase retardation of the beam wavefront irradiated from the LC lens device can be evaluated by polarizing microscope images with a monochromatic filter. Radial positions of each observed fringe are plotted and fitted with 2nd degree polynomial approximation. The number of appeared fringes is over 600 in whole lens aperture area and the correlation coefficients of all approximations are over 0.993 that seems enough ideal optical wavefront. The obtained maximum lens powers from the approximations are about ±4 m-1 which was satisfied both convex and concave lens characteristics; and their practical use for the tunable lens grade eyeglasses became more prospective.

SPIE OPTO, 2017, San Francisco, California, United States, Giichi Shibuya, Shohei Yamano, Hiroyuki Yoshida, and Masanori Ozaki "Active liquid-crystal deflector and lens with Fresnel structure", Proc. SPIE 10125, Emerging Liquid Crystal Technologies XII, 101250V (15 February 2017). DOI: https://doi.org/10.1117/12.2261113, A new type of tunable Fresnel deflector and lens composed of liquid crystal was developed. Combined structure of multiple interdigitated electrodes and the high-resistivity (HR) layer implements the saw-tooth distribution of electrical potential with only the planar surfaces of the transparent substrates. According to the numerical calculation and design, experimental devices were manufactured with the liquid crystal (LC) material sealed into the sandwiched flat glass plates of 0.7 mm thickness with rubbed alignment layers set to an anti-parallel configuration. Fabricated beam deflector with no moving parts shows the maximum tilt angle of ±1.3 deg which can apply for optical image stabilizer (OIS) of micro camera. We also discussed and verified their lens characteristics to be extended more advanced applications. Transparent interdigitated electrodes were concentrically aligned on the lens aperture with the insulator gaps under their boundary area. The diameter of the lens aperture was 30 mm and the total number of Fresnel zone was 100. Phase retardation of the beam wavefront irradiated from the LC lens device can be evaluated by polarizing microscope images with a monochromatic filter. Radial positions of each observed fringe are plotted and fitted with 2nd degree polynomial approximation. The number of appeared fringes is over 600 in whole lens aperture area and the correlation coefficients of all approximations are over 0.993 that seems enough ideal optical wavefront. The obtained maximum lens powers from the approximations are about ±4 m-1 which was satisfied both convex and concave lens characteristics; and their practical use for the tunable lens grade eyeglasses became more prospective.