Effect of ion flux on helium retention in helium-irradiated tungsten

Helium retention in irradiated tungsten leads to swelling, pore formation, sample exfoliation and embrittlement with deleterious consequences in many applications. In particular, the use of tungsten in future nuclear fusion plants is proposed due to its good refractory properties. However, serious concerns about tungsten survivability stems from the fact that it must withstand severe irradiation conditions. In magnetic fusion as well as in inertial fusion (particularly with direct drive targets), tungsten components will be exposed to low and high energy ion (helium) irradiation, respectively. A common feature is that the most detrimental situations will take place in pulsed mode, i.e., high flux irradiation. There is increasing evidence on a correlation between a high helium flux and an enhancement of detrimental effects on tungsten. Nevertheless, the nature of these effects is not well understood due to the subtleties imposed by the exact temperature profile evolution, ion energy, pulse duration, existence of impurities and simultaneous irradiation with other species. Physically based Kinetic Monte Carlo is the technique of choice to simulate the evolution of radiation-induced damage inside solids in large temporal and space scales. We have used the recently developed code MMonCa (Modular Monte Carlo simulator), presented in this conference for the first time, to study He retention (and in general defect evolution) in tungsten samples irradiated with high intensity helium pulses. The code simulates the interactions among a large variety of defects and impurities (He and C) during the irradiation stage and the subsequent annealing steps. In addition, it allows us to vary the sample temperature to follow the severe thermo-mechanical effects of the pulses. In this work we will describe the helium kinetics for different irradiation conditions. A competition is established between fast helium cluster migration and trapping at large defects, being the temperature a determinant factor. In fact, high temperatures (induced by the pulses) are responsible for large vacancy cluster formation and subsequent additional trapping with respect to low flux irradiation.

Synchronizing chaotic optically-programmable digital circuits

In this paper an approach to the synchronization of chaotic circuits has been reported. It is based on an optically programmable logic cell and the signals involved are fully digital. It is based on the reception of the same input signal on sender and receiver and from this approach, with a posterior correlation between both outputs, an identical chaotic output is obtained in both systems. No conversion from analog to digital signals is needed. The model here presented is based on a computer simulation.

Chaos synchronization in optically programmable logic cells

A possible approach to the synchronization of chaotic circuits is reported. It is based on an Optically Programmable Logic Cell and the signals are fully digital. A method to study the characteristics of the obtained chaos is reported as well as a new technique to compare the obtained chaos from an emitter and a receiver. This technique allows the synchronization of chaotic signals. The signals received at the receiver, composed by the addition of information and chaotic signals, are compared with the chaos generated there and a pure information signal can be detected. Its application to cryptography in Optical Communications comes directly from these properties. The model here presented is based on a computer simulation.

Procedure for verification of sound source coverage over fa��ades according to the International Standard ISO 140-5

This paper presents a new verification procedure for sound source coverage according to ISO 140?5 requirements. The ISO 140?5 standard applies to the measurement of fa��ade insulation and requires a sound source able to achieve a sufficiently uniform sound field in free field conditions on the fa��ade under study. The proposed method involves the electroacoustic characterisation of the sound source in laboratory free field conditions (anechoic room) and the subsequent prediction by computer simulation of the sound free field radiated on a rectangular surface equal in size to the fa��ade being measured. The loudspeaker is characterised in an anechoic room under laboratory controlled conditions, carefully measuring directivity, and then a computer model is designed to calculate the acoustic free field coverage for different loudspeaker positions and fa��ade sizes. For each sound source position, the method provides the maximum direct acoustic level differences on a fa��ade specimen and therefore determines whether the loudspeaker verifies the maximum allowed level difference of 5 dB (or 10 dB for fa��ade dimensions greater than 5 m) required by the ISO standard. Additionally, the maximum horizontal dimension of the fa��ade meeting the standard is calculated and provided for each sound source position, both with the 5 dB and 10 dB criteria. In the last section of the paper, the proposed procedure is compared with another method used by the authors in the past to achieve the same purpose: in situ outdoor measurements attempting to recreate free field conditions. From this comparison, it is concluded that the proposed method is able to reproduce the actual measurements with high accuracy, for example, the ground reflection effect, at least at low frequencies, which is difficult to avoid in the outdoor measurement method, and it is fully eliminated with the proposed method to achieve the free field requisite.

Variance and covariance of actual relationship between relatives at one locus.

The relationship between pairs of individuals is an important topic in many areas of population and quantitative genetics. It is usually measured as the proportion of thegenome identical by descent shared by the pair and it can be inferred from pedigree information. But there is a variance in actual relationships as a consequence of Mendelian sampling, whose general formula has not been developed. The goal of this work is to develop this general formula for the one-locus situation,. We provide simple expressions for the variances and covariances of all actual relationships in an arbitrary complex pedigree. The proposed method relies on the use of the nine identity coefficients and the generalized relationship coefficients; formulas have been checked by computer simulation. Finally two examples for a short pedigree of dogs and a long pedigree of sheep are given.

Analysis and Modelling of the Structural Components of the Elbow Joint

A recent application of computer simulation is its use for the human body, which resembles a mechanism that is complemented by torques in the joints that are caused by the action of muscles and tendons. Among others, the application can be used to provide training in surgical procedures or to learn how the body works. Some of the other applications are to make a biped walk upright, to build robots that are designed on the human body or to make prostheses or robot arms to perform specific tasks. One of the uses of simulation is to optimise the movement of the human body by examining which muscles are activated and which should or should not be activated in order to improve a person?s movements. This work presents a model of the elbow joint, and by analysing the constraint equations using classic methods we go on to model the bones, muscles and tendons as well as the logic linked to the force developed by them when faced with a specific movement. To do this, we analyse the reference bibliography and the software available to perform the validation.

Unidad de efectos de audio en Simulink

La tecnolog��a moderna de computaci��n ha permitido cambiar radicalmente la investigaci��n tecnol��gica en todos los ��mbitos. El proceso general utilizado previamente consist��a en el desarrollo de prototipos anal��gicos, creando m��ltiples versiones del mismo hasta llegar al resultado adecuado. Este es un proceso costoso a nivel econ��mico y de carga de trabajo. Es por ello por lo que el proceso de investigaci��n actual aprovecha las nuevas tecnolog��as para lograr el objetivo final mediante la simulaci��n. Gracias al desarrollo de software para la simulaci��n de distintas ��reas se ha incrementado el ritmo de crecimiento de los avances tecnol��gicos y reducido el coste de los proyectos en investigaci��n y desarrollo. La simulaci��n, por tanto, permite desarrollar previamente prototipos simulados con un coste mucho menor para as�� lograr un producto final, el cual ser�� llevado a cabo en su ��mbito correspondiente. Este proceso no s��lo se aplica en el caso de productos con circuiter��a, si bien es utilizado tambi��n en productos programados. Muchos de los programas actuales trabajan con algoritmos concretos cuyo funcionamiento debe ser comprobado previamente, para despu��s centrarse en la codificaci��n del mismo. Es en este punto donde se encuentra el objetivo de este proyecto, simular algoritmos de procesado digital de la se��al antes de la codificaci��n del programa final. Los sistemas de audio est��n basados en su totalidad en algoritmos de procesado de la se��al, tanto anal��gicos como digitales, siendo estos ��ltimos los que est��n sustituyendo al mundo anal��gico mediante los procesadores y los ordenadores. Estos algoritmos son la parte m��s compleja del sistema, y es la creaci��n de nuevos algoritmos la base para lograr sistemas de audio novedosos y funcionales. Se debe destacar que los grupos de desarrollo de sistemas de audio presentan un amplio n��mero de miembros con cometidos diferentes, separando las funciones de programadores e ingenieros de la se��al de audio. Es por ello por lo que la simulaci��n de estos algoritmos es fundamental a la hora de desarrollar nuevos y m��s potentes sistemas de audio. Matlab es una de las herramientas fundamentales para la simulaci��n por ordenador, la cual presenta utilidades para desarrollar proyectos en distintos ��mbitos. Sin embargo, en creciente uso actualmente se encuentra el software Simulink, herramienta especializada en la simulaci��n de alto nivel que simplifica la dificultad de la programaci��n en Matlab y permite desarrollar modelos de forma m��s r��pida. Simulink presenta una completa funcionalidad para el desarrollo de algoritmos de procesado digital de audio. Por ello, el objetivo de este proyecto es el estudio de las capacidades de Simulink para generar sistemas de audio funcionales. A su vez, este proyecto pretende profundizar en los m��todos de procesado digital de la se��al de audio, logrando al final un paquete de sistemas de audio compatible con los programas de edici��n de audio actuales. ABSTRACT. Modern computer technology has dramatically changed the technological research in multiple areas. The overall process previously used consisted of the development of analog prototypes, creating multiple versions to reach the proper result. This is an expensive process in terms of an economically level and workload. For this reason actual investigation process take advantage of the new technologies to achieve the final objective through simulation. Thanks to the software development for simulation in different areas the growth rate of technological progress has been increased and the cost of research and development projects has been decreased. Hence, simulation allows previously the development of simulated protoypes with a much lower cost to obtain a final product, which will be held in its respective field. This process is not only applied in the case of circuitry products, but is also used in programmed products. Many current programs work with specific algorithms whose performance should be tested beforehand, which allows focusing on the codification of the program. This is the main point of this project, to simulate digital signal processing algorithms before the codification of the final program. Audio systems are entirely based on signal processing, both analog and digital systems, being the digital systems which are replacing the analog world thanks to the processors and computers. This algorithms are the most complex part of every system, and the creation of new algorithms is the most important step to achieve innovative and functional new audio systems. It should be noted that development groups of audio systems have a large number of members with different roles, separating them into programmers and audio signal engineers. For this reason, the simulation of this algorithms is essential when developing new and more powerful audio systems. Matlab is one of the most important tools for computer simulation, which has utilities to develop projects in different areas. However, the use of the Simulink software is constantly growing. It is a simulation tool specialized in high-level simulations which simplifies the difficulty of programming in Matlab and allows the developing of models faster. Simulink presents a full functionality for the development of algorithms for digital audio processing. Therefore, the objective of this project is to study the posibilities of Simulink to generate funcional audio systems. In turn, this projects aims to get deeper into the methods of digital audio signal processing, making at the end a software package of audio systems compatible with the current audio editing software.

Digital chaos synchronization in optical networks

A possible approach to the synchronization of chaotic circuits is reported. It is based on an Optically Programmable Logic Cell and as a consequence its output is digital, its application to cryptography in Optical Communications comes directly from its properties. The model here presented is based on a computer simulation.

Neuronanatomy, neurology and Bayesian networks

Bayesian networks are data mining models with clear semantics and a sound theoretical foundation. In this keynote talk we will pinpoint a number of neuroscience problems that can be addressed using Bayesian networks. In neuroanatomy, we will show computer simulation models of dendritic trees and classification of neuron types, both based on morphological features. In neurology, we will present the search for genetic biomarkers in Alzheimer's disease and the prediction of health-related quality of life in Parkinson's disease. Most of these challenging problems posed by neuroscience involve new Bayesian network designs that can cope with multiple class variables, small sample sizes, or labels annotated by several experts.

An��lisis param��trico de transiciones a bocinas

Las transiciones en gu��a de onda son las estructuras utilizadas en microondas para transferir y adaptar la se��al que viaja en un determinado sistema de transmisi��n (por ejemplo, un cable coaxial) a otro sistema de transmisi��n o a un sistema radiante (por ejemplo, una antena de bocina). Los dos sistemas de transmisi��n entre los que la transici��n adapta la se��al pueden ser distintos o del mismo tipo pero con alguna de sus dimensiones diferente. Existen diferentes transiciones de gu��a de onda que dependiendo de su utilidad son dise��adas y construidas con diferentes secciones: circular, rectangular, el��ptica o incluso combinaciones de ��stas. No es necesario que la secci��n de la gu��a presente una forma geom��trica conocida pero los est��ndares que se van a seguir hacen referencia en concreto a secciones rectangulares y circulares. En el trabajo que aqu�� se desarrolla se pretende optimizar por medio de simulaciones param��tricas una transici��n entre cable coaxial con conector tipo K y una gu��a de onda de secci��n circular que sigue el est��ndar presentado por Flann, Millitech y Antarfs para la banda WR34. La transici��n que va a ser objeto de este estudio se denomina transici��n tapered o transici��n conformada. Este tipo de transiciones se caracterizan por variar una de sus dimensiones progresivamente hasta llegar al tama��o definido en el est��ndar correspondiente. La manera de realizar la optimizaci��n de la transici��n se basar�� en el estudio del par��metro S11 que presente la estructura a lo largo de la banda de trabajo. Ya que se sigue el est��ndar WR34 la banda de trabajo que ��ste comprende va de 21,7 a 33 GHz. Se pretende conseguir que la respuesta del par��metro S11 se encuentre por debajo de -20 dB en la banda de WR34 como resultado del dise��o para poder contar de esta manera con una buena adaptaci��n. Finalmente se propondr�� un criterio a seguir para optimizar este tipo de transiciones siguiendo el objetivo de mejor adaptaci��n teniendo en cuenta el impacto de cada tramo sobre el rango de frecuencias en el que influye y se presentar��n las caracter��sticas finales que presenta la transici��n bajo estudio. En este documento se introduce de manera breve la utilidad de los transformadores de impedancias lambda cuartos en l��neas de transmisi��n, el estado del arte de las diferentes t��cnicas para su dise��o, y la propuesta de dise��o y caracterizaci��n objeto del presente trabajo. Posteriormente, se presenta el caso de estudio para el dise��o de la transici��n para ser integrada a una bocina de choke. Luego, se introduce el marco te��rico del trabajo presentando algunos ejemplos ilustrativos de tramos de gu��a de onda rectangular y gu��a de onda circular, introduciendo adaptadores de ��/4 en simulaciones. A continuaci��n, se explica la implementaci��n del modelo bajo estudio en CST (Computer Simulation Technology) Studio Suite. Finalmente se presenta la discusi��n de los resultados obtenidos, las conclusiones y l��neas futuras de trabajo. ABSTRACT. Waveguide transitions are structures used in microwave in order to transfer and adapt the signal that travels from a certain transmission system (e.g. coaxial cable) to other transmission system or to a radiant system (e.g. horn antenna). Both transmission systems between which the transition adapts the signal can be different or from the same type, but with differences in some of their dimensions. There are different waveguide transitions that, depending on their utility, are designed and constructed in different sections: circular, rectangular, elliptic or combinations of the former. The section of the guide does not have to have a known geometric shape, although the standards to be followed in this thesis apply to rectangular and circular sections. In the work here presented, we aim to optimize by means of parametric simulations, a transition between a coaxial cable with a K-type connector and a waveguide with circular section following the standard presented by Flann, Millitech y Antarfs for the band WR34. The transition studied is called tapered transition, which is characterized by the progressive variation of its dimensions, until reaching the defined size of the corresponding standard. The way of optimizing the transition will be based in the study of the parameter S11 presented by the structure along the bandwidth. Since the standard used is the WR34, the bandwidth can be defined from 21.7 up to 33 GHz. It is aimed that the response of the S11 parameter be lower equal than -20dB in the frequency band under study according to the design in order to be well matched. Finally, a criterion to follow is proposed in order to optimize these transitions type, following the better-match objective. That will be done taking into account the impact of each section on the frequency range in which influences and the final characteristics of the studied transition will be presented. In this document, it is briefly introduced the utility of quarter-wave impedance transformers in transmission lines, the state-of-art of the different techniques for their design, and the proposal of design and characterization aimed with this work. Afterwards, the study case for the design of the transition to be integrated with a choke horn antenna will be presented. Later, the theoretical frame work is introduced, giving some illustrative examples of rectangular and circular waveguide sections, and also introducing ��/4 adaptors in the simulations. Subsequently, the implementation of the model under study in CST (Computer Simulation Technology) Studio Suite will be explained. Finally, the discussion of the results, conclusion and future lines of the work are presented.

Estudio y validaci��n experimental del efecto de aire interno en un perfil aerodin��mico hueco

La presente investigaci��n se llev�� a cabo en la Universidad Polit��cnica de Madrid (Espa��a) conjuntamente con la Universidad Nacional Experimental del T��chira (Venezuela). El estudio consisti�� en dise��ar una cavidad interna dentro del perfil aerodin��mico 2415-3s, el cual fue desarrollado en la Universidad T��cnica Checa (Praga, Rep��blica Checa). Se realiz�� un estudio computacional, mediante la t��cnica del CFD, de diferentes modelos de cavidades internas en este perfil, para seleccionar el dise��o m��s adecuado, fabricando un prototipo en 3D; logrando de esta manera validar la simulaci��n computacional con los datos experimentales obtenidos con los ensayos en el t��nel de viento AF6109 de la Universidad Nacional Experimental del T��chira. Tambi��n se aplicaron t��cnicas de visualizaci��n en el t��nel de viento, como l��neas de corriente de humo y pel��culas de aceite sobre el perfil aerodin��mico. Dicho procedimiento permiti�� corroborar la validaci��n de la simulaci��n computacional. El perfil aerodin��mico seleccionado se denomin�� 2415-3s-TC, cuya caracter��stica principal consiste en tres canales independientes entre s��, alojados dentro de la cavidad interna, permitiendo que el flujo de aire forzado a trav��s de la cavidad, cambiara de direcci��n, para desembocar lo m��s tangencialmente, as�� como, lo m��s perpendicularmente posible al escal��n del perfil aerodin��mico 2415-3s. Esta configuraci��n de dise���� permiti�� elevar el coeficiente de sustentaci��n para ��ngulos de ataque mayores a 8��, as�� como para ��ngulos cercanos al ��ngulo cr��tico. ABSTRACT This research was conducted at the Polytechnic University of Madrid (Spain) together with the National Experimental University of T��chira (Venezuela). The study was to design an internal cavity within the airfoil 2415-3s, which was developed in the Czech Technical University (Prague, Czech Republic). A computational study was performed using CFD technique, different models of internal cavities in the profile to select the most appropriate design, manufacturing a prototype 3D; thus achieving validate the computer simulation with experimental data obtained from the tests in the wind tunnel AF6109 of the National Experimental University of T��chira. Visualization techniques were also applied in the wind tunnel, as streamlines smoke and oil films on the airfoil. This procedure corroborated validation of computational simulation. The airfoil selected denominated 2415-3s-TC, whose main characteristic consists of three independent channels each other, housed within the inner cavity, allowing the forced air flow through the cavity, change direction, to lead as more tangentially and, as perpendicular as possible to the step 2415-3s aerofoil. This configuration designed allowed increasing the lift coefficient for higher angles of attack to 8��, and for angles near the critical angle.

Hybrid wind-diesel power plant valuation and optimization using real option theory and dynamic programming

El sistema de energ��a e��lica-diesel h��brido tiene un gran potencial en la prestaci��n de suministro de energ��a a comunidades remotas. En comparaci��n con los sistemas tradicionales de diesel, las plantas de energ��a h��bridas ofrecen grandes ventajas tales como el suministro de capacidad de energ��a extra para "microgrids", reducci��n de los contaminantes y emisiones de gases de efecto invernadero, y la cobertura del riesgo de aumento inesperado del precio del combustible. El principal objetivo de la presente tesis es proporcionar nuevos conocimientos para la evaluaci��n y optimizaci��n de los sistemas de energ��a h��brido e��lico-diesel considerando las incertidumbres. Dado que la energ��a e��lica es una variable estoc��stica, ��sta no puede ser controlada ni predecirse con exactitud. La naturaleza incierta del viento como fuente de energ��a produce serios problemas tanto para la operaci��n como para la evaluaci��n del valor del sistema de energ��a e��lica-diesel h��brido. Por un lado, la regulaci��n de la potencia inyectada desde las turbinas de viento es una dif��cil tarea cuando opera el sistema h��brido. Por otro lado, el bene.cio econ��mico de un sistema e��lico-diesel h��brido se logra directamente a trav��s de la energ��a entregada a la red de alimentaci��n de la energ��a e��lica. Consecuentemente, la incertidumbre de los recursos e��licos incrementa la dificultad de estimar los beneficios globales en la etapa de planificaci��n. La principal preocupaci��n del modelo tradicional determinista es no tener en cuenta la incertidumbre futura a la hora de tomar la decisi��n de operaci��n. Con lo cual, no se prev�� las acciones operativas flexibles en respuesta a los escenarios futuros. El an��lisis del rendimiento y simulaci��n por ordenador en el Proyecto E��lico San Crist��bal demuestra que la incertidumbre sobre la energ��a e��lica, las estrategias de control, almacenamiento de energ��a, y la curva de potencia de aerogeneradores tienen un impacto significativo sobre el rendimiento del sistema. En la presente tesis, se analiza la relaci��n entre la teor��a de valoraci��n de opciones y el proceso de toma de decisiones. La opci��n real se desarrolla con un modelo y se presenta a trav��s de ejemplos pr��cticos para evaluar el valor de los sistemas de energ��a e��lica-diesel h��bridos. Los resultados muestran que las opciones operacionales pueden aportar un valor adicional para el sistema de energ��a h��brida, cuando esta flexibilidad operativa se utiliza correctamente. Este marco se puede aplicar en la optimizaci��n de la operaci��n a corto plazo teniendo en cuenta la naturaleza dependiente de la trayectoria de la pol��tica ��ptima de despacho, dadas las plausibles futuras realizaciones de la producci��n de energ��a e��lica. En comparaci��n con los m��todos de valoraci��n y optimizaci��n existentes, el resultado del caso de estudio num��rico muestra que la pol��tica de operaci��n resultante del modelo de optimizaci��n propuesto presenta una notable actuaci��n en la reducci��n del con- sumo total de combustible del sistema e��lico-diesel. Con el .n de tomar decisiones ��ptimas, los operadores de plantas de energ��a y los gestores de ��stas no deben centrarse s��lo en el resultado directo de cada acci��n operativa, tampoco deber��an tomar decisiones deterministas. La forma correcta es gestionar din��micamente el sistema de energ��a teniendo en cuenta el valor futuro condicionado en cada opci��n frente a la incertidumbre. ABSTRACT Hybrid wind-diesel power systems have a great potential in providing energy supply to remote communities. Compared with the traditional diesel systems, hybrid power plants are providing many advantages such as providing extra energy capacity to the micro-grid, reducing pollution and greenhouse-gas emissions, and hedging the risk of unexpected fuel price increases. This dissertation aims at providing novel insights for assessing and optimizing hybrid wind-diesel power systems considering the related uncertainties. Since wind power can neither be controlled nor accurately predicted, the energy harvested from a wind turbine may be considered a stochastic variable. This uncertain nature of wind energy source results in serious problems for both the operation and value assessment of the hybrid wind-diesel power system. On the one hand, regulating the uncertain power injected from wind turbines is a difficult task when operating the hybrid system. On the other hand, the economic profit of a hybrid wind-diesel system is achieved directly through the energy delivered to the power grid from the wind energy. Therefore, the uncertainty of wind resources has increased the difficulty in estimating the total benefits in the planning stage. The main concern of the traditional deterministic model is that it does not consider the future uncertainty when making the dispatch decision. Thus, it does not provide flexible operational actions in response to the uncertain future scenarios. Performance analysis and computer simulation on the San Cristobal Wind Project demonstrate that the wind power uncertainty, control strategies, energy storage, and the wind turbine power curve have a significant impact on the performance of the system. In this dissertation, the relationship between option pricing theory and decision making process is discussed. A real option model is developed and presented through practical examples for assessing the value of hybrid wind-diesel power systems. Results show that operational options can provide additional value to the hybrid power system when this operational flexibility is correctly utilized. This framework can be applied in optimizing short term dispatch decisions considering the path-dependent nature of the optimal dispatch policy, given the plausible future realizations of the wind power production. Comparing with the existing valuation and optimization methods, result from numerical example shows that the dispatch policy resulting from the proposed optimization model exhibits a remarkable performance in minimizing the total fuel consumption of the wind-diesel system. In order to make optimal decisions, power plant operators and managers should not just focus on the direct outcome of each operational action; neither should they make deterministic decisions. The correct way is to dynamically manage the power system by taking into consideration the conditional future value in each option in response to the uncertainty.

Construcci��n modular ligera energ��ticamente eficiente

Esta tesis trata sobre la construcci��n modular ligera, dentro del contexto de la eficiencia energ��tica y de cara a los conceptos de nZEB (near Zero Energy Building) y NZEB (Net Zero Energy Building) que se manejan en el ��mbito europeo y espec��ficamente dentro del marco regulador de la Directiva 2010/31 UE. En el contexto de la Uni��n Europea, el sector de la edificaci��n representa el 40% del total del consumo energ��tico del continente. Asumiendo la necesidad de reducir este consumo se han planteado, desde los organismos de direcci��n europeos, unos objetivos (objetivos 20-20-20) para hacer m��s eficiente el parque edificatorio. Estos objetivos, que son vinculantes en t��rminos de legislaci��n, comprometen a todos los estados miembros a conseguir la meta de reducci��n de consumo y emisiones de GEI (Gases de Efecto Invernadero) antes del a��o 2020. Estos conceptos de construcci��n modular ligera (CML) y eficiencia energ��tica no suelen estar asociados por el hecho de que este tipo de construcci��n no suele estar destinada a un uso intensivo y no cuenta con unos cerramientos con niveles de aislamiento de acuerdo a las normativas locales o c��digos de edificaci��n de cada pa��s. El objetivo de nZEB o NZEB, e incluso Energy Plus, seg��n sea el caso, necesariamente (y as�� queda establecido en las normativas), depender�� no s��lo de la mejora de los niveles de aislamiento de los edificios, sino tambi��n de la implementaci��n de sistemas de generaci��n renovables, independientemente del tipo de sistema constructivo con el que se trabaje e incluso de la tipolog��a edificatoria. Si bien es cierto que los niveles de industrializaci��n de la sociedad tecnol��gica actual han alcanzado varias de las fases del proceso constructivo - sobre todo en cuanto a elementos compositivos de los edificios- tambi��n lo es el hecho de que las cotas de desarrollo conseguidas en el ��mbito de la construcci��n no llegan al nivel de evoluci��n que se puede apreciar en otros campos de las ingenier��as como la aeron��utica o la industria del autom��vil. Aunque desde finales del siglo pasado existen modelos y proyectos testimoniales de construcci��n industrializada ligera (CIL) e incluso ya a principios del siglo XX, ejemplos de construcci��n modular ligera (CML), como la Casa Voisin, la industrializaci��n de la construcci��n de edificios no ha sido una constante progresiva con un nivel de comercializaci��n equiparable al de la construcci��n masiva y pesada. Los t��rminos construcci��n industrializada, construcci��n prefabricada, construcci��n modular y construcci��n ligera, no siempre hacen referencia a lo mismo y no siempre son sin��nimos entre s��. Un edificio puede ser prefabricado y no ser modular ni ligero y tal es el caso, por poner un ejemplo, de la construcci��n con paneles de hormig��n prefabricado. Lo que s�� es una constante es que en el caso de la construcci��n modular ligera, la prefabricaci��n y la industrializaci��n, casi siempre vienen impl��citas en muchos ejemplos hist��ricos y actuales. Con relaci��n al concepto de eficiencia energ��tica (nZEB o incluso NZEB), el mismo no suele estar ligado a la construcci��n modular ligera y/o ligera industrializada; m��s bien se le ve unido a la idea de cerramientos masivos con gran inercia t��rmica propios de est��ndares de dise��o como el Passivhaus; y aunque com��nmente a la construcci��n ligera se le asocian otros conceptos que le restan valor (corta vida ��til; funci��n y formas limitadas, fuera de todo orden est��tico; limitaci��n en los niveles de confort, etc.), los avances que se van alcanzando en materia de tecnolog��as para el aprovechamiento de la energ��a y sistemas de generaci��n renovables, pueden conseguir revertir estas ideas y unificar el criterio de eficiencia + construcci��n modular ligera. Prototipos y proyectos acad��micos��� como el concurso Solar Decathlon que se celebra desde el a��o 2002 promovido por el DOE (Departamento de Energ��a de los Estados Unidos), y que cuenta con ediciones europeas como las de los a��os 2010 y 2012, replantean la idea de la construcci��n industrializada, modular y ligera dentro del contexto de la eficiencia energ��tica, con prototipos de viviendas de �� 60m2, propuestos por las universidades concursantes, y cuyo objetivo es alcanzar y/o desarrollar el concepto de NZEB (Net Zero Energy Building) o edificio de energ��a cero. Esta opci��n constructiva no s��lo representa durabilidad, seguridad y est��tica, sino tambi��n, rapidez en la fabricaci��n y montaje, adem��s de altas prestaciones energ��ticas como se ha podido demostrar en las sucesivas ediciones del Solar Decathlon. Este tipo de iniciativas de desarrollo de tecnolog��as constructivas, no s��lo apuntan a la eficiencia energ��tica sino al concepto global de energ��a neta, Energ��a plus o cero emisiones de CO2. El nivel de emisiones por la fabricaci��n y puesta en obra de los materiales de construcci��n depende, en muchos casos, no solo de la propia naturaleza del material, sino tambi��n de la cantidad de recursos utilizados para producir una unidad de medida determinada (kg, m3, m2, ml, etc). En este sentido podr��a utilizarse, en muchos casos, el argumento v��lido de que a menos peso, y a menos tama��o, menos emisiones globales de gases de efecto invernadero y menos contaminaci��n. Para el trabajo de investigaci��n de esta tesis se han tomado como referencias v��lidas para estudio, prototipos tanto de CML (Modular 3D) como de CIL (panelizado y elementos 2D), dado que para los fines de an��lisis de las prestaciones energ��ticas de los materiales de cerramiento, ambos sistemas son equiparables. Para poder llegar a la conclusi��n fundamental de este trabajo de tesis doctoral - que consiste en demostrar la viabilidad tecnol��gica/ industrial que supone la combinaci��n de la eficiencia energ��tica y la construcci��n modular ligera - se parte del estudio del estado de la t��cnica ( desde la selecci��n de los materiales y los posibles procesos de industrializaci��n en f��brica, hasta su puesta en obra, funcionamiento y uso, bajo los conceptos de consumo cero, cero emisiones de carbono y plus energ��tico). Adem��s -y con un estado de la t��cnica que identifica la situaci��n actual- se llevan a cabo pruebas y ensayos con un prototipo a escala natural y c��lulas de ensayo, para comprobar el comportamiento de los elementos compositivos de los mismos, frente a unas condicionantes clim��ticas determinadas. Este tipo de resultados se contrastan con los obtenidos mediante simulaciones inform��ticas basadas en los mismos par��metros y realizadas en su mayor��a mediante m��todos simplificados de c��lculos, validados por los organismos competentes en materia de eficiencia energ��tica en la edificaci��n en Espa��a y de acuerdo a la normativa vigente. ABSTRACT This thesis discusses lightweight modular construction within the context of energy efficiency in nZEB (near Zero Energy Building) and NZEB (Net Zero Energy Building) both used in Europe and, specifically, within the limits of the regulatory framework of the EU Directive 2010/31. In the European Union the building sector represents 40% of the total energy consumption of the continent. Due to the need to reduce this consumption, European decision-making institutions have proposed aims (20-20-20 aims) to render building equipment more efficient. These aims are bound by law and oblige all member States to endeavour to reduce consumption and GEI emissions before the year 2020. Lightweight modular construction concepts and energy efficiency are not generally associated because this type of building is not normally meant for intensive use and does not have closures with insulation levels which fit the local regulations or building codes of each country. The objective of nZEB or NZEB and even Energy Plus, depending on each case, will necessarily be associated (as established in the guidelines) not only with the improvement of insulation levels in buildings, but also with the implementation of renewable systems of generation, independent of the type of building system used and of the building typology. Although it is true that the levels of industrialisation in the technological society today have reached several of the building process phases - particularly in the composite elements of buildings - it is also true that the quotas of development achieved in the area of construction have not reached the evolutionary levelfound in other fields of engineering, such as aeronautics or the automobile industry. Although there have been models and testimonial projects of lightweight industrialised building since the end of last century, even going back as far as the beginning of the XX century with examples of lightweight modular construction such as the Voisin House, industrialisation in the building industry has not been constant nor is its comercialisation comparable to massive and heavy construction. The terms industrialised building, prefabricated building, modular building and lightweight building, do not always refer to the same thing and they are not always synonymous. A building can be prefabricated yet not be modular or lightweight. To give an example, this is the case of building with prefabricated concrete panels. What is constant is that, in the case of lightweight modular construction, prefabrication and industrialisation are almost always implicit in many historical and contemporary examples. Energy efficiency (nZEB or even NZEB) is not normally linked to lightweight modular construction and/or industrialised lightweight; rather, it is united to the idea of massive closureswith high thermal inertia typical of design standards such as the Passive House; and although other concepts that subtract value from it are generally associated with lightweight building (short useful life, limited forms and function, inappropriate toany aesthetic pattern; limitation in comfort levels, etc.), the advances being achieved in technology for benefitting from energy and renewable systems of generation may well reverse these ideas and unify the criteria of efficiency + lightweight modular construction. Academic prototypes and projects - such as the Solar Decathlon competition organised by the US Department of Energy and celebrated since 2002, with its corresponding European events such as those held in 2010 and 2012, place a different slant on the idea of industrialised, modular and lightweight building within the context of energy efficiency, with prototypes of homes measuring approximately 60m2, proposed by university competitors, whose aim is to reach and/or develop the NZEB concept, or the zero energy building. This building option does not only signify durability, security and aesthetics, but also fast manufacture and assembly. It also has high energy benefits, as has been demonstrated in successive events of the Solar Decathlon. This type of initiative for the development of building technologies, does not only aim at energy efficiency, but also at the global concept of net energy, Energy Plus and zero CO2 emissions. The level of emissions in the manufacture and introduction of building materials in many cases depends not only on the inherent nature of the material, but also on the quantity of resources used to produce a specific unit of measurement (kg, m3, m2, ml, etc.). Thus in many cases itcould be validly arguedthat with less weight and smaller size, there will be fewer global emissions of greenhouse effect gases and less contamination. For the research carried out in this thesis prototypes such as the CML (3D Module) and CIL (panelled and elements) have been used as valid study references, becauseboth systems are comparablefor the purpose of analysing the energy benefits of closure materials. So as to reach a basic conclusion in this doctoral thesis - that sets out to demonstrate the technological/industrial viability of the combination of energy efficiency and lightweight modular construction - the departure point is the study of the state of the technique (from the selection of materials and the possible processes of industrialisation in manufacture, to their use on site, functioning and use, respecting the concepts of zero consumption, zero emissions of carbon and Energy Plus). Moreover, with the state of the technique identifying the current situation, tests and practices have been carried out with a natural scale prototype and test cells so as to verify the behaviour of the composite elements of these in certain climatic conditions. These types of result are contrasted with those obtained through computer simulation based on the same parameters and done, principally, using simplified methods of calculation, validated by institutions competent in energy efficiency in Spanish building and in line with the rules in force.

Urban microclimate and thermal comfort modelling: strategies for urban renovation

The urban microclimate plays an important role in building energy consumption and thermal comfort in outdoor spaces. Nowadays, cities need to increase energy efficiency, reduce pollutant emissions and mitigate the evident lack of sustainability. In light of this, attention has focused on the bioclimatic concepts use in the urban development. However, the speculative unsustainability of the growth model highlights the need to redirect the construction sector towards urban renovation using a bioclimatic approach. The public space plays a key role in improving the quality of today���s cities, especially in terms of providing places for citizens to meet and socialize in adequate thermal conditions. Thermal comfort affects perception of the environment, so microclimate conditions can be decisive for the success or failure of outdoor urban spaces and the activities held in them. For these reasons, the main focus of this work is on the definition of bioclimatic strategies for existing urban spaces, based on morpho-typological components, urban microclimate conditions and comfort requirements for all kinds of citizens. Two case studies were selected in Madrid, in a social housing neighbourhood constructed in the 1970s based on Rational Architecture style. Several renovation scenarios were performed using a computer simulation process based in ENVI-met and diverse microclimate conditions were compared. In addition, thermal comfort evaluation was carried out using the Universal Thermal Climate Index (UTCI) in order to investigate the relationship between microclimate conditions and thermal comfort perception. This paper introduces the microclimate computer simulation process as a valuable support for decision-making for neighbourhood renovation projects in order to provide new and better solutions according to the thermal quality of public spaces and reducing energy consumption by creating and selecting better microclimate areas.

Improved high-speed de-excitation system for brushless synchronous machines tested on a 20 MVA hydro-generator

Synchronous machines with brushless excitation have the disadvantage that the field winding is not accessible for the de-excitation of the machine. This means that, despite the proper operation of the protection system, the slow de-excitation time constant may produce severe damage in the event of an internal short circuit. A high-speed de-excitation system for these machines was developed, and this study presents the continuation of a previously published study. This study presents the design by computer simulation and the results of the first commissioning of this de-excitation system in a commercial 20 MVA hydro-generator. The de-excitation is achieved by inserting resistance in the field circuit, obtaining a dynamic response similar to that achieved in machines with static excitation. In this case, a non-linear discharge resistor was used, making the dynamic response even better.