Desarrollo de un sistema de almacenamiento térmico para la central termosolar Astexol 2

En este proyecto se elabora la ingeniería básica de un sistema de almacenamiento térmico para la central termosolar Astexol 2 (Badajoz, España). Para ello, primeramente se decidió que el sistema térmico de almacenamiento a diseñar fuera indirecto de dos tanques con sales fundidas. Una vez seleccionado el tipo de almacenamiento adecuado, se seleccionó la capacidad de almacenamiento óptima, en base a unos objetivos establecidos para la instalación del TES en Astexol 2. Finalmente, se procedió con el diseño de los equipos principales y con la realización de los planos de implantación y de los PFD’s (diagramas de flujo) y P&ID’s (diagramas de instrumentación y control) del sistema de almacenamiento. ABSTRACT This project includes the basic engineering of a thermal storage system for the concentrating solar power plant Astexol 2 (Badajoz, Spain). First of all, it was decided that the type of thermal storage system to design had to be an indirect two-tank molten salt thermal storage system. Once the proper type of storage system was chosen, the optimum storage capacity was selected, according to the main aims designated for the thermal storage system installation in Astexol 2.Finally, the design of the main equipment of the thermal storage system was done, together with the elaboration of the associated plot plans, PFD’s (Process Flow Diagrams) and P&ID’s (Process and Instrumentation Diagrams).

Application of PZT and FBG impedance sensors for structural health monitoring of reinforced concrete beams strengthened with FRP composite materials

Esta Tesis tiene como objetivo principal el desarrollo de métodos de identificación del daño que sean robustos y fiables, enfocados a sistemas estructurales experimentales, fundamentalmente a las estructuras de hormigón armado reforzadas externamente con bandas fibras de polímeros reforzados (FRP). El modo de fallo de este tipo de sistema estructural es crítico, pues generalmente es debido a un despegue repentino y frágil de la banda del refuerzo FRP originado en grietas intermedias causadas por la flexión. La detección de este despegue en su fase inicial es fundamental para prevenir fallos futuros, que pueden ser catastróficos. Inicialmente, se lleva a cabo una revisión del método de la Impedancia Electro-Mecánica (EMI), de cara a exponer sus capacidades para la detección de daño. Una vez la tecnología apropiada es seleccionada, lo que incluye un analizador de impedancias así como novedosos sensores PZT para monitorización inteligente, se ha diseñado un procedimiento automático basado en los registros de impedancias de distintas estructuras de laboratorio. Basándonos en el hecho de que las mediciones de impedancias son posibles gracias a una colocación adecuada de una red de sensores PZT, la estimación de la presencia de daño se realiza analizando los resultados de distintos indicadores de daño obtenidos de la literatura. Para que este proceso sea automático y que no sean necesarios conocimientos previos sobre el método EMI para realizar un experimento, se ha diseñado e implementado un Interfaz Gráfico de Usuario, transformando la medición de impedancias en un proceso fácil e intuitivo. Se evalúa entonces el daño a través de los correspondientes índices de daño, intentando estimar no sólo su severidad, sino también su localización aproximada. El desarrollo de estos experimentos en cualquier estructura genera grandes cantidades de datos que han de ser procesados, y algunas veces los índices de daño no son suficientes para una evaluación completa de la integridad de una estructura. En la mayoría de los casos se pueden encontrar patrones de daño en los datos, pero no se tiene información a priori del estado de la estructura. En este punto, se ha hecho una importante investigación en técnicas de reconocimiento de patrones particularmente en aprendizaje no supervisado, encontrando aplicaciones interesantes en el campo de la medicina. De ahí surge una idea creativa e innovadora: detectar y seguir la evolución del daño en distintas estructuras como si se tratase de un cáncer propagándose por el cuerpo humano. En ese sentido, las lecturas de impedancias se emplean como información intrínseca de la salud de la propia estructura, de forma que se pueden aplicar las mismas técnicas que las empleadas en la investigación del cáncer. En este caso, se ha aplicado un algoritmo de clasificación jerárquica dado que ilustra además la clasificación de los datos de forma gráfica, incluyendo información cualitativa y cuantitativa sobre el daño. Se ha investigado la efectividad de este procedimiento a través de tres estructuras de laboratorio, como son una viga de aluminio, una unión atornillada de aluminio y un bloque de hormigón reforzado con FRP. La primera ayuda a mostrar la efectividad del método en sencillos escenarios de daño simple y múltiple, de forma que las conclusiones extraídas se aplican sobre los otros dos, diseñados para simular condiciones de despegue en distintas estructuras. Demostrada la efectividad del método de clasificación jerárquica de lecturas de impedancias, se aplica el procedimiento sobre las estructuras de hormigón armado reforzadas con bandas de FRP objeto de esta tesis, detectando y clasificando cada estado de daño. Finalmente, y como alternativa al anterior procedimiento, se propone un método para la monitorización continua de la interfase FRP-Hormigón, a través de una red de sensores FBG permanentemente instalados en dicha interfase. De esta forma, se obtienen medidas de deformación de la interfase en condiciones de carga continua, para ser implementadas en un modelo de optimización multiobjetivo, cuya solución se haya por medio de una expansión multiobjetivo del método Particle Swarm Optimization (PSO). La fiabilidad de este último método de detección se investiga a través de sendos ejemplos tanto numéricos como experimentales. ABSTRACT This thesis aims to develop robust and reliable damage identification methods focused on experimental structural systems, in particular Reinforced Concrete (RC) structures externally strengthened with Fiber Reinforced Polymers (FRP) strips. The failure mode of this type of structural system is critical, since it is usually due to sudden and brittle debonding of the FRP reinforcement originating from intermediate flexural cracks. Detection of the debonding in its initial stage is essential thus to prevent future failure, which might be catastrophic. Initially, a revision of the Electro-Mechanical Impedance (EMI) method is carried out, in order to expose its capabilities for local damage detection. Once the appropriate technology is selected, which includes impedance analyzer as well as novel PZT sensors for smart monitoring, an automated procedure has been design based on the impedance signatures of several lab-scale structures. On the basis that capturing impedance measurements is possible thanks to an adequately deployed PZT sensor network, the estimation of damage presence is done by analyzing the results of different damage indices obtained from the literature. In order to make this process automatic so that it is not necessary a priori knowledge of the EMI method to carry out an experimental test, a Graphical User Interface has been designed, turning the impedance measurements into an easy and intuitive procedure. Damage is then assessed through the analysis of the corresponding damage indices, trying to estimate not only the damage severity, but also its approximate location. The development of these tests on any kind of structure generates large amounts of data to be processed, and sometimes the information provided by damage indices is not enough to achieve a complete analysis of the structural health condition. In most of the cases, some damage patterns can be found in the data, but none a priori knowledge of the health condition is given for any structure. At this point, an important research on pattern recognition techniques has been carried out, particularly on unsupervised learning techniques, finding interesting applications in the medicine field. From this investigation, a creative and innovative idea arose: to detect and track the evolution of damage in different structures, as if it were a cancer propagating through a human body. In that sense, the impedance signatures are used to give intrinsic information of the health condition of the structure, so that the same clustering algorithms applied in the cancer research can be applied to the problem addressed in this dissertation. Hierarchical clustering is then applied since it also provides a graphical display of the clustered data, including quantitative and qualitative information about damage. The performance of this approach is firstly investigated using three lab-scale structures, such as a simple aluminium beam, a bolt-jointed aluminium beam and an FRP-strengthened concrete specimen. The first one shows the performance of the method on simple single and multiple damage scenarios, so that the first conclusions can be extracted and applied to the other two experimental tests, which are designed to simulate a debonding condition on different structures. Once the performance of the impedance-based hierarchical clustering method is proven to be successful, it is then applied to the structural system studied in this dissertation, the RC structures externally strengthened with FRP strips, where the debonding failure in the interface between the FRP and the concrete is successfully detected and classified, proving thus the feasibility of this method. Finally, as an alternative to the previous approach, a continuous monitoring procedure of the FRP-Concrete interface is proposed, based on an FBGsensors Network permanently deployed within that interface. In this way, strain measurements can be obtained under controlled loading conditions, and then they are used in order to implement a multi-objective model updating method solved by a multi-objective expansion of the Particle Swarm Optimization (PSO) method. The feasibility of this last proposal is investigated and successfully proven on both numerical and experimental RC beams strengthened with FRP.

Contribución al análisis eficiente y a la mejora de prestaciones de antenas reflectarray

El diseño de una antena reflectarray bajo la aproximación de periodicidad local requiere la determinación de la matriz de scattering de estructuras multicapa con metalizaciones periódicas para un gran número de geometrías diferentes. Por lo tanto, a la hora de diseñar antenas reflectarray en tiempos de CPU razonables, se necesitan herramientas númericas rápidas y precisas para el análisis de las estructuras periódicas multicapa. En esta tesis se aplica la versión Galerkin del Método de los Momentos (MDM) en el dominio espectral al análisis de las estructuras periódicas multicapa necesarias para el diseño de antenas reflectarray basadas en parches apilados o en dipolos paralelos coplanares. Desgraciadamente, la aplicación de este método numérico involucra el cálculo de series dobles infinitas, y mientras que algunas series convergen muy rápidamente, otras lo hacen muy lentamente. Para aliviar este problema, en esta tesis se propone un novedoso MDM espectral-espacial para el análisis de las estructuras periódicas multicapa, en el cual las series rápidamente convergente se calculan en el dominio espectral, y las series lentamente convergentes se calculan en el dominio espacial mediante una versión mejorada de la formulación de ecuaciones integrales de potenciales mixtos (EIPM) del MDM. Esta versión mejorada se basa en la interpolación eficiente de las funciones de Green multicapa periódicas, y en el cálculo eficiente de las integrales singulares que conducen a los elementos de la matriz del MDM. El novedoso método híbrido espectral-espacial y el tradicional MDM en el dominio espectral se han comparado en el caso de los elementos reflectarray basado en parches apilados. Las simulaciones numéricas han demostrado que el tiempo de CPU requerido por el MDM híbrido es alrededor de unas 60 veces más rápido que el requerido por el tradicional MDM en el dominio espectral para una precisión de dos cifras significativas. El uso combinado de elementos reflectarray con parches apilados y técnicas de optimización de banda ancha ha hecho posible diseñar antenas reflectarray de transmisiónrecepción (Tx-Rx) y polarización dual para aplicaciones de espacio con requisitos muy restrictivos. Desgraciadamente, el nivel de aislamiento entre las polarizaciones ortogonales en antenas DBS (típicamente 30 dB) es demasiado exigente para ser conseguido con las antenas basadas en parches apilados. Además, el uso de elementos reflectarray con parches apilados conlleva procesos de fabricación complejos y costosos. En esta tesis se investigan varias configuraciones de elementos reflectarray basadas en conjuntos de dipolos paralelos con el fin de superar los inconvenientes que presenta el elemento basado en parches apilados. Primeramente, se propone un elemento consistente en dos conjuntos apilados ortogonales de tres dipolos paralelos para aplicaciones de polarización dual. Se ha diseñado, fabricado y medido una antena basada en este elemento, y los resultados obtenidos para la antena indican que tiene unas altas prestaciones en términos de ancho de banda, pérdidas, eficiencia y discriminación contrapolar, además de requerir un proceso de fabricación mucho más sencillo que el de las antenas basadas en tres parches apilados. Desgraciadamente, el elemento basado en dos conjuntos ortogonales de tres dipolos paralelos no proporciona suficientes grados de libertad para diseñar antenas reflectarray de transmisión-recepción (Tx-Rx) de polarización dual para aplicaciones de espacio por medio de técnicas de optimización de banda ancha. Por este motivo, en la tesis se propone un nuevo elemento reflectarray que proporciona los grados de libertad suficientes para cada polarización. El nuevo elemento consiste en dos conjuntos ortogonales de cuatro dipolos paralelos. Cada conjunto contiene tres dipolos coplanares y un dipolo apilado. Para poder acomodar los dos conjuntos de dipolos en una sola celda de la antena reflectarray, el conjunto de dipolos de una polarización está desplazado medio período con respecto al conjunto de dipolos de la otra polarización. Este hecho permite usar solamente dos niveles de metalización para cada elemento de la antena, lo cual simplifica el proceso de fabricación como en el caso del elemento basados en dos conjuntos de tres dipolos paralelos coplanares. Una antena de doble polarización y doble banda (Tx-Rx) basada en el nuevo elemento ha sido diseñada, fabricada y medida. La antena muestra muy buenas presentaciones en las dos bandas de frecuencia con muy bajos niveles de polarización cruzada. Simulaciones numéricas presentadas en la tesis muestran que estos bajos de niveles de polarización cruzada se pueden reducir todavía más si se llevan a cabo pequeñas rotaciones de los dos conjuntos de dipolos asociados a cada polarización. ABSTRACT The design of a reflectarray antenna under the local periodicity assumption requires the determination of the scattering matrix of a multilayered structure with periodic metallizations for quite a large number of different geometries. Therefore, in order to design reflectarray antennas within reasonable CPU times, fast and accurate numerical tools for the analysis of the periodic multilayered structures are required. In this thesis the Galerkin’s version of the Method of Moments (MoM) in the spectral domain is applied to the analysis of the periodic multilayered structures involved in the design of reflectarray antennas made of either stacked patches or coplanar parallel dipoles. Unfortunately, this numerical approach involves the computation of double infinite summations, and whereas some of these summations converge very fast, some others converge very slowly. In order to alleviate this problem, in the thesis a novel hybrid MoM spectral-spatial domain approach is proposed for the analysis of the periodic multilayered structures. In the novel approach, whereas the fast convergent summations are computed in the spectral domain, the slowly convergent summations are computed by means of an enhanced Mixed Potential Integral Equation (MPIE) formulation of the MoM in the spatial domain. This enhanced formulation is based on the efficient interpolation of the multilayered periodic Green’s functions, and on the efficient computation of the singular integrals leading to the MoM matrix entries. The novel hybrid spectral-spatial MoM code and the standard spectral domain MoM code have both been compared in the case of reflectarray elements based on multilayered stacked patches. Numerical simulations have shown that the CPU time required by the hybrid MoM is around 60 times smaller than that required by the standard spectral MoM for an accuracy of two significant figures. The combined use of reflectarray elements based on stacked patches and wideband optimization techniques has made it possible to design dual polarization transmit-receive (Tx-Rx) reflectarrays for space applications with stringent requirements. Unfortunately, the required level of isolation between orthogonal polarizations in DBS antennas (typically 30 dB) is hard to achieve with the configuration of stacked patches. Moreover, the use of reflectarrays based on stacked patches leads to a complex and expensive manufacturing process. In this thesis, we investigate several configurations of reflectarray elements based on sets of parallel dipoles that try to overcome the drawbacks introduced by the element based on stacked patches. First, an element based on two stacked orthogonal sets of three coplanar parallel dipoles is proposed for dual polarization applications. An antenna made of this element has been designed, manufactured and measured, and the results obtained show that the antenna presents a high performance in terms of bandwidth, losses, efficiency and cross-polarization discrimination, while the manufacturing process is cheaper and simpler than that of the antennas made of stacked patches. Unfortunately, the element based on two sets of three coplanar parallel dipoles does not provide enough degrees of freedom to design dual-polarization transmit-receive (Tx-Rx) reflectarray antennas for space applications by means of wideband optimization techniques. For this reason, in the thesis a new reflectarray element is proposed which does provide enough degrees of freedom for each polarization. This new element consists of two orthogonal sets of four parallel dipoles, each set containing three coplanar dipoles and one stacked dipole. In order to accommodate the two sets of dipoles in each reflectarray cell, the set of dipoles for one polarization is shifted half a period from the set of dipoles for the other polarization. This also makes it possible to use only two levels of metallization for the reflectarray element, which simplifies the manufacturing process as in the case of the reflectarray element based on two sets of three parallel dipoles. A dual polarization dual-band (Tx-Rx) reflectarray antenna based on the new element has been designed, manufactured and measured. The antenna shows a very good performance in both Tx and Rx frequency bands with very low levels of cross-polarization. Numerical simulations carried out in the thesis have shown that the low levels of cross-polarization can be even made smaller by means of small rotations of the two sets of dipoles associated to each polarization.

Co-simulation Methodologies for Hybrid and Electric Vehicle Dynamics

In recent decades, full electric and hybrid electric vehicles have emerged as an alternative to conventional cars due to a range of factors, including environmental and economic aspects. These vehicles are the result of considerable efforts to seek ways of reducing the use of fossil fuel for vehicle propulsion. Sophisticated technologies such as hybrid and electric powertrains require careful study and optimization. Mathematical models play a key role at this point. Currently, many advanced mathematical analysis tools, as well as computer applications have been built for vehicle simulation purposes. Given the great interest of hybrid and electric powertrains, along with the increasing importance of reliable computer-based models, the author decided to integrate both aspects in the research purpose of this work. Furthermore, this is one of the first final degree projects held at the ETSII (Higher Technical School of Industrial Engineers) that covers the study of hybrid and electric propulsion systems. The present project is based on MBS3D 2.0, a specialized software for the dynamic simulation of multibody systems developed at the UPM Institute of Automobile Research (INSIA). Automobiles are a clear example of complex multibody systems, which are present in nearly every field of engineering. The work presented here benefits from the availability of MBS3D software. This program has proven to be a very efficient tool, with a highly developed underlying mathematical formulation. On this basis, the focus of this project is the extension of MBS3D features in order to be able to perform dynamic simulations of hybrid and electric vehicle models. This requires the joint simulation of the mechanical model of the vehicle, together with the model of the hybrid or electric powertrain. These sub-models belong to completely different physical domains. In fact the powertrain consists of energy storage systems, electrical machines and power electronics, connected to purely mechanical components (wheels, suspension, transmission, clutch…). The challenge today is to create a global vehicle model that is valid for computer simulation. Therefore, the main goal of this project is to apply co-simulation methodologies to a comprehensive model of an electric vehicle, where sub-models from different areas of engineering are coupled. The created electric vehicle (EV) model consists of a separately excited DC electric motor, a Li-ion battery pack, a DC/DC chopper converter and a multibody vehicle model. Co-simulation techniques allow car designers to simulate complex vehicle architectures and behaviors, which are usually difficult to implement in a real environment due to safety and/or economic reasons. In addition, multi-domain computational models help to detect the effects of different driving patterns and parameters and improve the models in a fast and effective way. Automotive designers can greatly benefit from a multidisciplinary approach of new hybrid and electric vehicles. In this case, the global electric vehicle model includes an electrical subsystem and a mechanical subsystem. The electrical subsystem consists of three basic components: electric motor, battery pack and power converter. A modular representation is used for building the dynamic model of the vehicle drivetrain. This means that every component of the drivetrain (submodule) is modeled separately and has its own general dynamic model, with clearly defined inputs and outputs. Then, all the particular submodules are assembled according to the drivetrain configuration and, in this way, the power flow across the components is completely determined. Dynamic models of electrical components are often based on equivalent circuits, where Kirchhoff’s voltage and current laws are applied to draw the algebraic and differential equations. Here, Randles circuit is used for dynamic modeling of the battery and the electric motor is modeled through the analysis of the equivalent circuit of a separately excited DC motor, where the power converter is included. The mechanical subsystem is defined by MBS3D equations. These equations consider the position, velocity and acceleration of all the bodies comprising the vehicle multibody system. MBS3D 2.0 is entirely written in MATLAB and the structure of the program has been thoroughly studied and understood by the author. MBS3D software is adapted according to the requirements of the applied co-simulation method. Some of the core functions are modified, such as integrator and graphics, and several auxiliary functions are added in order to compute the mathematical model of the electrical components. By coupling and co-simulating both subsystems, it is possible to evaluate the dynamic interaction among all the components of the drivetrain. ‘Tight-coupling’ method is used to cosimulate the sub-models. This approach integrates all subsystems simultaneously and the results of the integration are exchanged by function-call. This means that the integration is done jointly for the mechanical and the electrical subsystem, under a single integrator and then, the speed of integration is determined by the slower subsystem. Simulations are then used to show the performance of the developed EV model. However, this project focuses more on the validation of the computational and mathematical tool for electric and hybrid vehicle simulation. For this purpose, a detailed study and comparison of different integrators within the MATLAB environment is done. Consequently, the main efforts are directed towards the implementation of co-simulation techniques in MBS3D software. In this regard, it is not intended to create an extremely precise EV model in terms of real vehicle performance, although an acceptable level of accuracy is achieved. The gap between the EV model and the real system is filled, in a way, by introducing the gas and brake pedals input, which reflects the actual driver behavior. This input is included directly in the differential equations of the model, and determines the amount of current provided to the electric motor. For a separately excited DC motor, the rotor current is proportional to the traction torque delivered to the car wheels. Therefore, as it occurs in the case of real vehicle models, the propulsion torque in the mathematical model is controlled through acceleration and brake pedal commands. The designed transmission system also includes a reduction gear that adapts the torque coming for the motor drive and transfers it. The main contribution of this project is, therefore, the implementation of a new calculation path for the wheel torques, based on performance characteristics and outputs of the electric powertrain model. Originally, the wheel traction and braking torques were input to MBS3D through a vector directly computed by the user in a MATLAB script. Now, they are calculated as a function of the motor current which, in turn, depends on the current provided by the battery pack across the DC/DC chopper converter. The motor and battery currents and voltages are the solutions of the electrical ODE (Ordinary Differential Equation) system coupled to the multibody system. Simultaneously, the outputs of MBS3D model are the position, velocity and acceleration of the vehicle at all times. The motor shaft speed is computed from the output vehicle speed considering the wheel radius, the gear reduction ratio and the transmission efficiency. This motor shaft speed, somehow available from MBS3D model, is then introduced in the differential equations corresponding to the electrical subsystem. In this way, MBS3D and the electrical powertrain model are interconnected and both subsystems exchange values resulting as expected with tight-coupling approach.When programming mathematical models of complex systems, code optimization is a key step in the process. A way to improve the overall performance of the integration, making use of C/C++ as an alternative programming language, is described and implemented. Although this entails a higher computational burden, it leads to important advantages regarding cosimulation speed and stability. In order to do this, it is necessary to integrate MATLAB with another integrated development environment (IDE), where C/C++ code can be generated and executed. In this project, C/C++ files are programmed in Microsoft Visual Studio and the interface between both IDEs is created by building C/C++ MEX file functions. These programs contain functions or subroutines that can be dynamically linked and executed from MATLAB. This process achieves reductions in simulation time up to two orders of magnitude. The tests performed with different integrators, also reveal the stiff character of the differential equations corresponding to the electrical subsystem, and allow the improvement of the cosimulation process. When varying the parameters of the integration and/or the initial conditions of the problem, the solutions of the system of equations show better dynamic response and stability, depending on the integrator used. Several integrators, with variable and non-variable step-size, and for stiff and non-stiff problems are applied to the coupled ODE system. Then, the results are analyzed, compared and discussed. From all the above, the project can be divided into four main parts: 1. Creation of the equation-based electric vehicle model; 2. Programming, simulation and adjustment of the electric vehicle model; 3. Application of co-simulation methodologies to MBS3D and the electric powertrain subsystem; and 4. Code optimization and study of different integrators. Additionally, in order to deeply understand the context of the project, the first chapters include an introduction to basic vehicle dynamics, current classification of hybrid and electric vehicles and an explanation of the involved technologies such as brake energy regeneration, electric and non-electric propulsion systems for EVs and HEVs (hybrid electric vehicles) and their control strategies. Later, the problem of dynamic modeling of hybrid and electric vehicles is discussed. The integrated development environment and the simulation tool are also briefly described. The core chapters include an explanation of the major co-simulation methodologies and how they have been programmed and applied to the electric powertrain model together with the multibody system dynamic model. Finally, the last chapters summarize the main results and conclusions of the project and propose further research topics. In conclusion, co-simulation methodologies are applicable within the integrated development environments MATLAB and Visual Studio, and the simulation tool MBS3D 2.0, where equation-based models of multidisciplinary subsystems, consisting of mechanical and electrical components, are coupled and integrated in a very efficient way.

Construcción modular ligera energéticamente eficiente

Esta tesis trata sobre la construcción modular ligera, dentro del contexto de la eficiencia energética y de cara a los conceptos de nZEB (near Zero Energy Building) y NZEB (Net Zero Energy Building) que se manejan en el ámbito europeo y específicamente dentro del marco regulador de la Directiva 2010/31 UE. En el contexto de la Unión Europea, el sector de la edificación representa el 40% del total del consumo energético del continente. Asumiendo la necesidad de reducir este consumo se han planteado, desde los organismos de dirección europeos, unos objetivos (objetivos 20-20-20) para hacer más eficiente el parque edificatorio. Estos objetivos, que son vinculantes en términos de legislación, comprometen a todos los estados miembros a conseguir la meta de reducción de consumo y emisiones de GEI (Gases de Efecto Invernadero) antes del año 2020. Estos conceptos de construcción modular ligera (CML) y eficiencia energética no suelen estar asociados por el hecho de que este tipo de construcción 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 códigos de edificación de cada país. El objetivo de nZEB o NZEB, e incluso Energy Plus, según sea el caso, necesariamente (y así queda establecido en las normativas), dependerá no sólo de la mejora de los niveles de aislamiento de los edificios, sino también de la implementación de sistemas de generación renovables, independientemente del tipo de sistema constructivo con el que se trabaje e incluso de la tipología edificatoria. Si bien es cierto que los niveles de industrialización de la sociedad tecnológica actual han alcanzado varias de las fases del proceso constructivo - sobre todo en cuanto a elementos compositivos de los edificios- también lo es el hecho de que las cotas de desarrollo conseguidas en el ámbito de la construcción no llegan al nivel de evolución que se puede apreciar en otros campos de las ingenierías como la aeronáutica o la industria del automóvil. Aunque desde finales del siglo pasado existen modelos y proyectos testimoniales de construcción industrializada ligera (CIL) e incluso ya a principios del siglo XX, ejemplos de construcción modular ligera (CML), como la Casa Voisin, la industrialización de la construcción de edificios no ha sido una constante progresiva con un nivel de comercialización equiparable al de la construcción masiva y pesada. Los términos construcción industrializada, construcción prefabricada, construcción modular y construcción ligera, no siempre hacen referencia a lo mismo y no siempre son sinónimos entre sí. Un edificio puede ser prefabricado y no ser modular ni ligero y tal es el caso, por poner un ejemplo, de la construcción con paneles de hormigón prefabricado. Lo que sí es una constante es que en el caso de la construcción modular ligera, la prefabricación y la industrialización, casi siempre vienen implícitas en muchos ejemplos históricos y actuales. Con relación al concepto de eficiencia energética (nZEB o incluso NZEB), el mismo no suele estar ligado a la construcción modular ligera y/o ligera industrializada; más bien se le ve unido a la idea de cerramientos masivos con gran inercia térmica propios de estándares de diseño como el Passivhaus; y aunque comúnmente a la construcción ligera se le asocian otros conceptos que le restan valor (corta vida útil; función y formas limitadas, fuera de todo orden estético; limitación en los niveles de confort, etc.), los avances que se van alcanzando en materia de tecnologías para el aprovechamiento de la energía y sistemas de generación renovables, pueden conseguir revertir estas ideas y unificar el criterio de eficiencia + construcción modular ligera. Prototipos y proyectos académicos– como el concurso Solar Decathlon que se celebra desde el año 2002 promovido por el DOE (Departamento de Energía de los Estados Unidos), y que cuenta con ediciones europeas como las de los años 2010 y 2012, replantean la idea de la construcción industrializada, modular y ligera dentro del contexto de la eficiencia energética, 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 energía cero. Esta opción constructiva no sólo representa durabilidad, seguridad y estética, sino también, rapidez en la fabricación y montaje, además de altas prestaciones energéticas como se ha podido demostrar en las sucesivas ediciones del Solar Decathlon. Este tipo de iniciativas de desarrollo de tecnologías constructivas, no sólo apuntan a la eficiencia energética sino al concepto global de energía neta, Energía plus o cero emisiones de CO2. El nivel de emisiones por la fabricación y puesta en obra de los materiales de construcción depende, en muchos casos, no solo de la propia naturaleza del material, sino también de la cantidad de recursos utilizados para producir una unidad de medida determinada (kg, m3, m2, ml, etc). En este sentido podría utilizarse, en muchos casos, el argumento válido de que a menos peso, y a menos tamaño, menos emisiones globales de gases de efecto invernadero y menos contaminación. Para el trabajo de investigación de esta tesis se han tomado como referencias válidas para estudio, prototipos tanto de CML (Modular 3D) como de CIL (panelizado y elementos 2D), dado que para los fines de análisis de las prestaciones energéticas de los materiales de cerramiento, ambos sistemas son equiparables. Para poder llegar a la conclusión fundamental de este trabajo de tesis doctoral - que consiste en demostrar la viabilidad tecnológica/ industrial que supone la combinación de la eficiencia energética y la construcción modular ligera - se parte del estudio del estado de la técnica ( desde la selección de los materiales y los posibles procesos de industrialización en fábrica, hasta su puesta en obra, funcionamiento y uso, bajo los conceptos de consumo cero, cero emisiones de carbono y plus energético). Además -y con un estado de la técnica que identifica la situación actual- se llevan a cabo pruebas y ensayos con un prototipo a escala natural y células de ensayo, para comprobar el comportamiento de los elementos compositivos de los mismos, frente a unas condicionantes climáticas determinadas. Este tipo de resultados se contrastan con los obtenidos mediante simulaciones informáticas basadas en los mismos parámetros y realizadas en su mayoría mediante métodos simplificados de cálculos, validados por los organismos competentes en materia de eficiencia energética en la edificación en España 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.

Defective localization of the NADPH phagocyte oxidase to Salmonella-containing phagosomes in tumor necrosis factor p55 receptor-deficient macrophages

Tumor necrosis factor receptor (TNFR) p55-knockout (KO) mice are susceptible profoundly to Salmonella infection. One day after peritoneal inoculation, TNFR-KO mice harbor 1,000-fold more bacteria in liver and spleen than wild-type mice despite the formation of well organized granulomas. Macrophages from TNFR-KO mice produce abundant quantities of reactive oxygen and nitrogen species in response to Salmonella but nevertheless exhibit poor bactericidal activity. Treatment with IFN-γ enhances killing by wild-type macrophages but does not restore the killing defect of TNFR-KO cells. Bactericidal activity of macrophages can be abrogated by a deletion in the gene encoding TNFα but not by saturating concentrations of TNF-soluble receptor, suggesting that intracellular TNFα can regulate killing of Salmonella by macrophages. Peritoneal macrophages from TNFR-KO mice fail to localize NADPH oxidase-containing vesicles to Salmonella-containing vacuoles. A TNFR-KO mutation substantially restores virulence to an attenuated mutant bacterial strain lacking the type III secretory system encoded by Salmonella pathogenicity island 2 (SPI2), suggesting that TNFα and SPI2 have opposing actions on a common pathway of vesicular trafficking. TNFα–TNFRp55 signaling plays a critical role in the immediate innate immune response to an intracellular pathogen by optimizing the delivery of toxic reactive oxygen species to the phagosome.

Striking a balance: Modulation of the actin cytoskeleton by Salmonella

Salmonella spp. have evolved the ability to enter into cells that are normally nonphagocytic. The internalization process is the result of a remarkable interaction between the bacteria and the host cells. Immediately on contact, Salmonella delivers a number of bacterial effector proteins into the host cell cytosol through the function of a specialized organelle termed the type III secretion system. Initially, two of the delivered proteins, SopE and SopB, stimulate the small GTP-binding proteins Cdc42 and Rac. SopE is an exchange factor for these GTPases, and SopB is an inositol polyphosphate phosphatase. Stimulation of Cdc42 and Rac leads to marked actin cytoskeleton rearrangements, which are further enhanced by SipA, a Salmonella protein also delivered into the host cell by the type III secretion system. SipA lowers the critical concentration of G-actin, stabilizes F-actin at the site of bacterial entry, and increases the bundling activity of the host-cell protein T-plastin (fimbrin). The cellular responses stimulated by Salmonella are short-lived; therefore, immediately after bacterial entry, the cell regains its normal architecture. Remarkably, this process is mediated by SptP, another target of the type III secretion system. SptP exert its function by serving as a GTPase-activating protein for Cdc42 and Rac, turning these G proteins off after their stimulation by the bacterial effectors SopE and SopB. The balanced interaction of Salmonella with host cells constitutes a remarkable example of the sophisticated nature of a pathogen/host relationship shaped by evolution through a longstanding coexistence.

Generation of representation models for complex systems using Lagrangian functions

In this article, a new methodology is presented to obtain representation models for a priori relation z = u(x1, x2, . . . ,xn) (1), with a known an experimental dataset zi; x1i ; x2i ; x3i ; . . . ; xni i=1;2;...;p· In this methodology, a potential energy is initially defined over each possible model for the relationship (1), what allows the application of the Lagrangian mechanics to the derived system. The solution of the Euler–Lagrange in this system allows obtaining the optimal solution according to the minimal action principle. The defined Lagrangian, corresponds to a continuous medium, where a n-dimensional finite elements model has been applied, so it is possible to get a solution for the problem solving a compatible and determined linear symmetric equation system. The computational implementation of the methodology has resulted in an improvement in the process of get representation models obtained and published previously by the authors.

An introduction to alysidal algebra (V): phenomenological components

Purpose – This paper aims to refer to a subjective approach to a type of complex system: human ecosystems, referred to as deontical impure systems (DIS) to capture a set of properties fundamental to the distinction between human and natural ecosystems. There are four main phenomenological components: directionality, intensity, connection energy and volume. The paper establishes thermodynamics of deontical systems based on the Law of Zipf and the temperature of information. Design/methodology/approach – Mathematical and logical development of human society structure. Findings – A fundamental question in this approach to DIS is the intensity or forces of a relation. Concepts are introduced as the system volume and propose a system thermodynamic theory. It hints at the possibility of adapting the fractal theory by introducing the fractal dimension of the system. Originality/value – This paper is a continuation of other previous papers and developing the theory of DIS.

Evolution of Outcrossing in Experimental Populations of Caenorhabditis elegans

Caenorhabditis elegans can reproduce exclusively by self-fertilization. Yet, males can be maintained in laboratory populations, a phenomenon that continues to puzzle biologists. In this study we evaluated the role of males in facilitating adaptation to novel environments. For this, we contrasted the evolution of a fitness component exclusive to outcrossing in experimental populations of different mating systems. We introgressed a modifier of outcrossing into a hybrid population derived from several wild isolates to transform the wild-type androdioecious mating system into a dioecious mating system. By genotyping 375 single-nucleotide polymorphisms we show that the two populations had similar standing genetic diversity available for adaptation, despite the occurrence of selection during their derivation. We then performed replicated experimental evolution under the two mating systems from starting conditions of either high or low levels of diversity, under defined environmental conditions of discrete non-overlapping generations, constant density at high population sizes (N = 10(4)), no obvious spatial structure and abundant food resources. During 100 generations measurements of sex ratios and male competitive performance showed: 1) adaptation to the novel environment; 2) directional selection on male frequency under androdioecy; 3) optimal outcrossing rates of 0.5 under androdioecy; 4) the existence of initial inbreeding depression; and finally 5) that the strength of directional selection on male competitive performance does not depend on male frequencies. Taken together, these results suggest that androdioecious males are maintained at intermediate frequencies because outcrossing is adaptive.

Novel target-field method for designing shielded biplanar shim and gradient coils

A new method is presented here for the systematic design of biplanar shielded shim and gradient coils, for use in magnetic resonance imaging (MRI) and other applications. The desired target field interior to the coil is specified in advance, and a winding pattern is then designed to produce a field that matches the target as closely as possible. Both gradient and shim coils can be designed by this approach, and the target region can be located asymmetrically within the coil. The interior target field may be matched at two or more interior locations, to improve accuracy. When shields are present, the winding patterns are designed so that the fields exterior to the biplanar coil are made as small as possible. The method is illustrated here by the design of some transverse gradient and shim coils.