The application of biomechanics to penalty corner drag-flick training: a case of Study

The penalty corner is one of the most important game situations in field hockey with one third of all goals resulting from this tactical situation. The aim of this study was to develop and apply a training method, based on previous studies, to improve the drag- flick skill on a young top-class field hockey player. A young top-class player exercised three times per week using specific drills over a four week period. A VICON optoelectronic system (Oxford Metrics, Oxford, UK) was employed to capture twenty drag-flicks, with six cameras sampling at 250 Hz, prior and after the training period. In order to analyze pre- and post-test differences a dependent t-test was carried out. Angular velocities and the kinematic sequence were similar to previous studies. The player improved (albeit not significantly) the angular velocity of the stick. The player increased front foot to the ball at T1 (p < 0.01) and the drag-flick distances. The range of motion from the front leg decreased from T1 to T6 after the training period (p < 0.01). The specific training sessions conducted with the player improved some features of this particular skill. This article shows how technical knowledge can help with the design of training programs and whether some drills are more effective than others.

Wave reflection at a stent

A simple analytical expression has been derived to calculate the characteristics of a wave that reflects at a stent implanted in a uniform vessel. The stent is characterized by its length and the wave velocity in the stented region. The reflected wave is proportional to the time derivative of the incident wave. The reflection coefficient is a small quantity of the order of the length of the stent divided by the wavelength of the unstented vessel. The results obtained coincide with those obtained numerically by Charonko et al. The main simplifications used are small amplitude of the waves so that equations can be linearized and that the length of the stent is small enough so that the values of the wave functions are nearly uniform along the stent. Both assumptions hold in typical situations.

Magneto-optic current sensor with Faraday mirror for linear birefringence compensation

Fiber optic sensors have some advantages in subjects related with electrical current and magnetic field measurement. In spite of the optical fiber utilization advantages we have to take into account undesirable effects, which are present in real non-ideal optical fibers. In telecommunication and sensor application fields the presence of inherent and induced birefringence is crucial. The presence of birefringence may cause an undesirable change in the polarization state. In order to compensate the linear birefringence a promising method has been chosen. This method employs orthogonal polarization conjugation in the back propagation direction of the light wave in the fiber. A study and a simulation of an experimental setup are realized with the advantage of a significant sensitivity improvement.

1000x shadow-free mirror-based Köhler concentrator

A new design for a photovoltaic concentrator, the most recent advance based on the Kohler concept, is presented. The system is mirror-based, and with geometry that guaranties a maximum sunlight collection area (without shadows, like those caused by secondary stages or receivers and heat-sinks in other mirror-based systems). Designed for a concentration of 1000x, this off axis system combines both good acceptance angle and good irradiance uniformity on the solar cell. The advanced performance features (concentration-acceptance products ?CAP- about 0.73 and affordable peak and average irradiances) are achieved through the combination of four reflective folds combined with four refractive surfaces, all of them free-form, performing Köhler integration 2 . In Köhler devices, the irradiance uniformity is not achieved through additional optical stages (TIR prisms), thus no complex/expensive elements to manufacture are required. The rim angle and geometry are such that the secondary stage and receivers are hidden below the primary mirrors, so maximum collection is assured. The entire system was designed to allow loose assembly/alignment tolerances (through high acceptance angle) and to be manufactured using already well-developed methods for mass production, with high potential for low cost. The optical surfaces for Köhler integration, although with a quite different optical behavior, have approximately the same dimensions and can be manufactured with the same techniques as the more traditional secondary optical elements used for concentration (typically plastic injection molding or glass molding).

A reflection suppression technique for far field antenna measurements

This paper presents a reflection suppression technique for far field antenna measurements. The technique is based on a source reconstruction over a surface greater than the antenna itself. To be able to perform the reflection construction the next steps are required: the complete far field antenna pattern is obtained through interpolation of the acquired cuts, the currents are obtained through a holographic technique, the field out of the antenna area is filtered, and the pattern is reconstructed. The algorithm is used with measurements in the LEHA-UPM antenna measurement facilities and in the outdoor far field facility of LIT INPE in Brazil.

Optimisation of a Low-Speed Wind Tunnel. Analysis and Redesign of Corner Vanes.

This paper includes the experimental study, analysis, redesign and subsequent test of the parts of a closed circuit, low speed wind tunnel which are relevant in terms of total pressure loss. The objective is to lower the energy consumption of this system for given conditions in test chamber, so as to reduce the operational costs. In order to achieve this objective, several tasks were performed as the text shows in its different parts. For these tasks, the ETSIAE wind tunnel was used, although the results of this work can be extrapolated to any wind tunnel with the same characteristics. Part II presents a theoretical previous study of the general running of a closed circuit, low speed wind tunnel, as well as the followed procedure to conduct experimental tests for obtaining the total pressure loss in its parts. Results from these tests and their analysis are included in this part. In part III, the analysis of the influence of corner 1 on the pressure loss takes place. As it is said in this part, corner 1 has great importance in the total pressure loss of the wind tunnel. Therefore, it is the first part that should be modified in order to improve the performances of the wind tunnel. During part IV, an optimised guide vane is designed in order to reduce the pressure loss in corner 1 of the wind tunnel. Software MISES is used to achieve this goal by means of selecting the optimum guide vane. In order to introduce the new guide vane in wind tunnels with affordable costs, the easily constructable criterion is kept during design. For this reason, the guide vane will consist of simple aerodynamic contours. Part V includes some possible improvements for the proposed guide vane, in order to evaluate if there is room for improvement in its design. Finally, part VI includes the tests that were conducted in the wind tunnel with the new guide vane cascade and the analysis of their results, in order to asses whether the proposed design fulfills the requirement of lowering the total pressure loss in the wind tunnel. Part VII gathers the main ideas resulting from the whole work.

Towards cost reduction in concentrating solar power: innovative design for an efficient fresnel based solar field

Energía termosolar (de concentración) es uno de los nombres que hacen referencia en español al término inglés “concentrating solar power”. Se trata de una tecnología basada en la captura de la potencia térmica de la radiación solar, de forma que permita alcanzar temperaturas capaces de alimentar un ciclo termodinámico convencional (o avanzado); el futuro de esta tecnología depende principalmente de su capacidad para concentrar la radiación solar de manera eficiente y económica. La presente tesis está orientada hacia la resolución de ciertos problemas importantes relacionados con este objetivo. La mencionada necesidad de reducir costes en la concentración de radiación solar directa, asegurando el objetivo termodinámico de calentar un fluido hasta una determinada temperatura, es de vital importancia. Los colectores lineales Fresnel han sido identificados en la literatura científica como una tecnología con gran potencial para alcanzar esta reducción de costes. Dicha tecnología ha sido seleccionada por numerosas razones, entre las que destacan su gran libertad de diseño y su actual estado inmaduro. Con el objetivo de responder a este desafío se desarrollado un detallado estudio de las propiedades ópticas de los colectores lineales Fresnel, para lo cual se han utilizado métodos analíticos y numéricos de manera combinada. En primer lugar, se han usado unos modelos para la predicción de la localización y la irradiación normal directa del sol junto a unas relaciones analíticas desarrolladas para estudiar el efecto de múltiples variables de diseño en la energía incidente sobre los espejos. Del mismo modo, se han obtenido analíticamente los errores debidos al llamado “off-axis aberration”, a la apertura de los rayos reflejados en los espejos y a las sombras y bloqueos entre espejos. Esto ha permitido la comparación de diferentes formas de espejo –planos, circulares o parabólicos–, así como el diseño preliminar de la localización y anchura de los espejos y receptor sin necesidad de costosos métodos numéricos. En segundo lugar, se ha desarrollado un modelo de trazado de rayos de Monte Carlo con el objetivo de comprobar la validez del estudio analítico, pero sobre todo porque este no es preciso en el estudio de la reflexión en espejos. El código desarrollado está específicamente ideado para colectores lineales Fresnel, lo que ha permitido la reducción del tiempo de cálculo en varios órdenes de magnitud en comparación con un programa comercial más general. Esto justifica el desarrollo de un nuevo código en lugar de la compra de una licencia de otro programa. El modelo ha sido usado primeramente para comparar la intensidad de flujo térmico y rendimiento de colectores Fresnel, con y sin reflector secundario, con los colectores cilíndrico parabólicos. Finalmente, la conjunción de los resultados obtenidos en el estudio analítico con el programa numérico ha sido usada para optimizar el campo solar para diferentes orientaciones –Norte-Sur y Este-Oeste–, diferentes localizaciones –Almería y Aswan–, diferentes inclinaciones hacia el Trópico –desde 0 deg hasta 32 deg– y diferentes mínimos de intensidad del flujo en el centro del receptor –10 kW/m2 y 25 kW/m2–. La presente tesis ha conducido a importantes descubrimientos que deben ser considerados a la hora de diseñar un campo solar Fresnel. En primer lugar, los espejos utilizados no deben ser plano, sino cilíndricos o parabólicos, ya que los espejos curvos implican mayores concentraciones y rendimiento. Por otro lado, se ha llegado a la conclusión de que la orientación Este-Oeste es más propicia para localizaciones con altas latitudes, como Almería, mientras que en zonas más cercanas a los trópicos como Aswan los campos Norte-Sur conducen a mayores rendimientos. Es de destacar que la orientación Este-Oeste requiere aproximadamente la mitad de espejos que los campos Norte-Sur, puediendo estar inclinados hacia los Trópicos para mejorar el rendimiento, y que alcanzan parecidos valores de intensidad térmica en el receptor todos los días a mediodía. Sin embargo, los campos con orientación Norte-Sur permiten un flujo más constante a lo largo de un día. Por último, ha sido demostrado que el uso de diseños pre-optimizados analíticamente, con anchura de espejos y espaciado entre espejos variables a lo ancho del campo, pueden implicar aumentos de la energía generada por metro cuadrado de espejos de hasta el 6%. El rendimiento óptico anual de los colectores cilíndrico parabólicos es 23 % mayor que el rendimiento de los campos Fresnel en Almería, mientras que la diferencia es de solo 9 % en Aswan. Ello implica que, para alcanzar el mismo precio de electricidad que la tecnología de referencia, la reducción de costes de instalación por metro cuadrado de espejo debe estar entre el 10 % y el 25 %, y que los colectores lineales Fresnel tienen más posibilidades de ser desarrollados en zonas de bajas latitudes. Como consecuencia de los estudios desarrollados en esta tesis se ha patentado un sistema de almacenamiento que tiene en cuenta la variación del flujo térmico en el receptor a lo largo del día, especialmente para campos con orientación Este-Oeste. Este invento permitiría el aprovechamiento de la energía incidente durante más parte del año, aumentando de manera apreciable los rendimientos óptico y térmico. Abstract Concentrating solar power is the common name of a technology based on capturing the thermal power of solar radiation, in a suitable way to reach temperatures able to activate a conventional (or advanced) thermodynamic cycle to generate electricity; this quest mainly depends on our ability to concentrate solar radiation in a cheap and efficient way. The present thesis is focused to highlight and help solving some of the important issues related to this problem. The need of reducing costs in concentrating the direct solar radiation, but without jeopardizing the thermodynamic objective of heating a fluid up to the required temperature, is of prime importance. Linear Fresnel collectors have been identified in the scientific literature as a technology with high potential to reach this cost reduction. This technology has been selected because of a number of reasons, particularly the degrees of freedom of this type of concentrating configuration and its current immature state. In order to respond to this challenge, a very detailed exercise has been carried out on the optical properties of linear Fresnel collectors. This has been done combining analytic and numerical methods. First, the effect of the design variables on the ratio of energy impinging onto the reflecting surface has been studied using analytically developed equations, together with models that predict the location and direct normal irradiance of the sun at any moment. Similarly, errors due to off-axis aberration, to the aperture of the reflected energy beam and to shading and blocking effects have been obtained analytically. This has allowed the comparison of different shapes of mirrors –flat, cylindrical or parabolic–, as well as a preliminary optimization of the location and width of mirrors and receiver with no need of time-consuming numerical models. Second, in order to prove the validity of the analytic results, but also due to the fact that the study of the reflection process is not precise enough when using analytic equations, a Monte Carlo Ray Trace model has been developed. The developed code is designed specifically for linear Fresnel collectors, which has reduced the computing time by several orders of magnitude compared to a wider commercial software. This justifies the development of the new code. The model has been first used to compare radiation flux intensities and efficiencies of linear Fresnel collectors, both multitube receiver and secondary reflector receiver technologies, with parabolic trough collectors. Finally, the results obtained in the analytic study together with the numeric model have used in order to optimize the solar field for different orientations –North-South and East-West–, different locations –Almería and Aswan–, different tilts of the field towards the Tropic –from 0 deg to 32 deg– and different flux intensity minimum requirements –10 kW/m2 and 25 kW/m2. This thesis work has led to several important findings that should be considered in the design of Fresnel solar fields. First, flat mirrors should not be used in any case, as cylindrical and parabolic mirrors lead to higher flux intensities and efficiencies. Second, it has been concluded that, in locations relatively far from the Tropics such as Almería, East-West embodiments are more efficient, while in Aswan North- South orientation leads to a higher annual efficiency. It must be noted that East-West oriented solar fields require approximately half the number of mirrors than NS oriented fields, can be tilted towards the Equator in order to increase the efficiency and attain similar values of flux intensity at the receiver every day at midday. On the other hand, in NS embodiments the flux intensity is more even during each single day. Finally, it has been proved that the use of analytic designs with variable shift between mirrors and variable width of mirrors across the field can lead to improvements in the electricity generated per reflecting surface square meter up to 6%. The annual optical efficiency of parabolic troughs has been found to be 23% higher than the efficiency of Fresnel fields in Almería, but it is only around 9% higher in Aswan. This implies that, in order to attain the same levelized cost of electricity than parabolic troughs, the required reduction of installation costs per mirror square meter is in the range of 10-25%. Also, it is concluded that linear Fresnel collectors are more suitable for low latitude areas. As a consequence of the studies carried out in this thesis, an innovative storage system has been patented. This system takes into account the variation of the flux intensity along the day, especially for East-West oriented solar fields. As a result, the invention would allow to exploit the impinging radiation along longer time every day, increasing appreciably the optical and thermal efficiencies.

Rem : a los dos lados del espejo = (Rem at both sides of the mirror)

Cuando se trata de Rem Koolhaas, su espejo no refleja una sola imagen sino múltiples, es un prisma poliédrico. Su espejo nos devuelve el Rem mediático, el intelectual, el conceptualizador, el constructor, el analista, el periodista, el actor... En el caso de esta investigación, fijamos el punto de mira en el Rem COMUNICADOR. “Rem a los dos lados del espejo” se enmarca en una investigación sobre los medios de comunicación de arquitectura, su reflejo en la producción arquitectónica y viceversa. Se trata de llegar a discernir si comunicación y producción arquitectónica colisionan y confluyen en el caso de grandes comunicadores como Rem Koolhaas, si el mensaje y el medio transmisor adquieren las mismas cualidades. Centrándose en la figura de Rem Koolhaas, la tesis aborda la evolución de su faceta comunicativa y las transformaciones sucesivas en el campo de la comunicación arquitectónica, en paralelo a su evolución conceptual a lo largo de su trayectoria. La investigación, por tanto, no se centra tanto en su componente teórica o en la práctica arquitectónica de OMA, sino en la exposición de su producción al mundo, especialmente a través de sus ensayos y libros. “Delirious New York” y “SMLXL” son un reflejo del momento conceptual en que se inscriben, y contienen mucha información sobre los referentes gráficos que irremediablemente han influido en su composición. Especialmente, la aparición de “SMLXL” supuso un revulsivo para el mundo de la comunicación arquitectónica, porque puso el foco sobre la importancia de dejar atrás un discurso narrativo linea y unifocal, para afrontar la comunicación barajando múltiples variables, y aproximaciones, en un proceso similar al desarrollo de un proyecto de arquitectura. Presenta un diseño muy novedoso y una edición extremadamente cuidada, que atiende a parámetros mucho más ambiciosos que los meramente narrativos. Profundiza en la necesidad de una temática global, planteando cuál es la aproximación más apropiada para cada uno de los proyectos que describe, transmitiendo al lector una percepción más allá de lo estrictamente visual, más próximo a lo sensorial. Además, su enorme repercusión a nivel internacional y el gran interés que despertó (no solamente entre los arquitectos, sino también entre diseñadores gráficos, publicistas, personas provenientes de todo tipo de tendencias artísticas y público en general), provocó la globalización del fenómeno de las publicaciones arquitectónicas y puso de manifiesto la importancia de la comunicación como una disciplina en sí misma, dentro de la producción arquitectónica en la era actual. A pesar de la importancia de “SMLXL” a todos los niveles, la presente tesis plantea que, donde realmente se culmina esa experiencia comunicativa, es en “Content”, al incluir nuevos parámetros relacionados con la fusión conceptual de continente y contenido. Es en esta publicación donde el objeto de la comunicación y la expresión de la misma se convierten en un único elemento, que se rige por leyes similares. En este caso, la ley fundamental es la aplicación hasta sus máximas consecuencias de la “cultura de la congestión”, tanto en el mensaje como en el medio, generando lo que hemos convenido en denominar “comunicación congestiva”. Esta concepción deviene en que necesariamente se materialice como un producto efímero, desechable, casi virtual, porque responde a las condiciones de un momento muy concreto y específico y fuera de ese contexto pierde su significación.. La “cultura de la congestión” empieza a surgir en los planteamientos de Koolhaas en la Architectural Association School of Architecture de Londres, bajo la tutela de Elia Zenghelis. Posteriormente se desarrolla en su manifiesto retroactivo sobre Manhattan, “Delirious New York”, donde declara la guerra abierta al urbanismo del movimiento moderno y afirma que la ciudad realmente contemporánea es aquella que es fruto de un desarrollo no planificado, hiperdensa y posible gracias a los avances tecnológicos de su era. Finalmente comienza a materializarse en la Diploma Unit 9 de la AA, donde entra como profesor en 1975, dejando una huella indeleble en las generaciones posteriores de arquitectos que pasaron dicha unidad. Rem Koolhaas es ante todo un intelectual y por ello, todo el constructo teórico sobre la metrópolis comienza a reflejarse en su obra a través de OMA desde el comienzo de su producción. Podemos decir a grandes rasgos que su carrera está marcada por dos hitos históricos fundamentales que determinan tres etapas diferenciadas en su producción. En sus primeros años de profesión, Koolhaas sigue fascinado por la metrópolis urbana y la aplicación del método paranoico crítico a su producción arquitectónica. Es un arquitecto profundamente surrealista. Entiende este método como una estrategia de conocimiento y aproximación al mundo que le rodea: “dejar salir el inconsciente pero sostenerlo con las muletas de la racionalidad”. Pero lo que en realidad le interesa es su aplicación a la gran escala, el “Bigness”, y por ello, participa en proyectos muy ambiciosos de los que surgen conceptos que, más allá de resultar premiados o no, han dejado una huella ideológica en el devenir de la arquitectura. Entre estos proyectos, cabe destacar su propuesta para el Parque de la Villette o la Très Grande Bibliotèque de París. Sus proyectos de esta época destilan una gran carga conceptual, que devienen en unos interiores sorprendentes pero una apariencia exterior sobria o incluso podríamos decir "povera", por el uso de materiales efímeros, poco habituales en la macro-arquitectura hasta ese momento. Súbitamente, en 1997, explotó el denominado “Efecto Bilbao”, de la mano de Frank Gehry (1). El Museo Guggenheim de Bilbao, con su espectacularidad, sus formas pregnantes e imposibles, impacta al mundo. Nace la era de la “Arquitectura del Espectáculo”; la transformación de la ciudad a través de ICONOS que actúen como nodos de atracción y concentración en torno a los cuales supuestamente se revitaliza la actividad económica, cultural y sociopolítica de la ciudad, como si a través de un único gesto se pudieran regenerar todos los tejidos internos de la urbe. Rem Koolhaas comprende rápidamente que la aproximación a la ciudad ha cambiado y, sobre todo, el mercado. En el mundo de la globalización, la única manera de llegar a materializar el “Bigness”, es encerrando sus ejercicios intelectuales en formas pregnantes, bellas, icónicas, espectaculares. Koolhaas encuentra su marca personal en la estética “Stealth”, proveniente de los aviones de combate facetados para evitar los radares, elaborados en los años 80. De esta época surgen proyectos como la Casa da Música de Oporto o la Biblioteca de Seattle; ambos edificios son iconos facetados, de belleza pregnante, que dejan una huella indeleble en la ciudad y provocan, al igual que el Guggenheim, un cierto efecto de recuperación y revitalización en el entorno en que se asientan, al menos de manera temporal. En cualquier caso, Koolhaas nunca abandona los ejercicios meramente teóricos, pero segrega su actividad en dos: OMA produce aquello que tiene vocación de ser construido y se rige por los parámetros del mercado global y AMO, la otra cara del espejo de Rem, aplica el pensamiento arquitectónico a campos no explorados, sin la dependencia de agentes externos, pudiendo permitirse ser un laboratorio puramente experimental. En este escenario, llega el 11 de septiembre de 2001 y el ataque a las Torres Gemelas de Nueva York tiene efectos devastadores a todos los niveles, significando, en un período de tiempo sorprendentemente corto, un cambio en el orden mundial. Rem Koolhaas da entonces un giro de 180 grados, dirige su mirada hacia China, donde entiende que sus aportaciones tienen un beneficio social más directo que en occidente. (2) Para presentar al mundo su nuevo cambio de rumbo y la creación del “Think Tank” AMO, plantea una gran exposición en la NeueGallerie de Berlín bajo el título de “Content”, experiencia paralela a la edición del libro con el mismo título, que inicialmente nace como “catálogo de la exposición, pero que internamente siempre se concibió como el documento más trascendente en el estudio desde “SMLXL”. Sin embargo, en muchos aspectos se trata de su opuesto: una publicación con formato revista, de tapa blanda, con paginado muy fino, formato de "folleto de supermercado" y contenido hiperdenso. Es un experimento efímero, fugaz, ligero, barato, de “usar y tirar”. De hecho, está fuera de stock, ya no se edita. Probablemente Rem Koolhaas desaprobaría que se hiciera una investigación que pusiera el foco sobre el mismo, porque diez años después de su publicación seguramente opine que su vigencia ha caducado. Sin embargo, muestra con una claridad meridiana el estado conceptual y vital de OMA en el momento de su publicación y representa, además un verdadero hito en la comunicación arquitectónica, un punto de no retorno, el máximo exponente de lo que hemos denominado “comunicación congestiva”. La presente tesis plantea que “Content” contiene la esencia de la mayor aportación de Rem Koolhaas al mundo de la arquitectura: la transformación profunda y definitiva de la comunicación arquitectónica mediante la convergencia del estado conceptual y la transmisión del mismo. Su legado arquitectónico y conceptual ha marcado a todas las generaciones posteriores de manera indeleble. Sus ensayos, sus teorías, sus proyectos y sus edificaciones ya pertenecen a la historia de la arquitectura, sin ninguna duda. Pero es su revisión del concepto de la comunicación en arquitectura lo que ha tenido y tendrá un reflejo inmediato en las generaciones futuras, no solamente en la comunicación sino en su arquitectura, a través de un intercambio biyectivo. El planteamiento a futuro sería determinar qué sucede tras “Content”, tras la hiperdensidad máxima, tras la cultura de la congestión visual; qué es lo que propone Koolhaas y qué se va a plantear también en el mundo de la comunicación arquitectónica. Para ello, estudiaremos en profundidad sus últimos proyectos relacionados con la comunicación, como su propuesta para la Biennale de Arquitectura de Venecia de 2014, su intensa investigación sobre el “Metabolismo” en “Project Japan: Metabolism Talks...”, o la dirección de sus últimos planteamientos territoriales. En los últimos tiempos Rem Koolhaas habla de “Preservación”, de “Sobriedad”, de “Esencialismo”, de “Performance”... El autor intelectual de la cultura de la congestión habla ahora de la “low density”...como no podía ser de otra manera en la otra cara del espejo. En definitiva, el color blanco como suma de todos los colores, todas las longitudes de onda del espectro visible recibidas al tiempo. ABSTRACT When talking about Rem Koolhaas, the mirror does not only reflect one but numerous images: it is nothing but a polyhedral prism. His mirror gives us the image of Rem the media celebrity, the intellectual, the conceptualizer, the builder, the analyst, the journalist, the actor... This research sets the spotlight on Rem the COMMUNICATOR. "Rem on both sides of the mirror" belongs to a research on architectural media, its influence on the architectural production and vice versa. It is aimed at getting to discern whether communication and architectural production collide and converge in the case of great communicators such as Rem Koolhaas, and whether the message and transmission media acquire the same features. Focusing on the figure of Rem Koolhaas, this thesis addresses the evolution of his communicative facet and the successive transformations in the field of architectural communication, parallel to the conceptual evolution he underwent throughout his career. Therefore, this research is not so much focused on his theoretical component or on the OMA’s architectural practice, but on the exhibition of his production to the world, especially through his essays and books. "Delirious New York" and "SMLXL" hold up a mirror to the conceptual moment they are part of, and contain a great deal of information about the graphic references that have inevitably influenced his work. Specially, the launch of "SMLXL" was a salutary shock for the architectural communication world, since it set the spotlight on the importance of leaving a linear and unifocal narrative behind in order to face communication considering multiple variables and approaches, based on a process similar to the development of an architectural project. It offers a very innovative design and an extremely careful editing, which deals with parameters much more ambitious than those merely narrative. It explores the need for a global subject and suggests the most appropriate approach for each of the projects described, giving the reader a closer insight to the sensory that goes beyond what’s strictly visual. In addition, its huge international impact and the great interest shown, not only by architects but also by graphic designers, publishers, people from all kinds of artistic trends and the general public, led to the globalisation of the architectural publications phenomenon and brought the importance of communication as a discipline in itself, within the architectural production in the age at hand, to light. Despite the importance of "SMLXL" at all levels, this thesis suggests that the communication experience really culminates in "Content", for it includes new conceptual parameters associated with the container-content conceptual fusion. It is in this book where the purpose of communication and the expression of such become a single element, ruled by similar laws. In this particular case, the fundamental law is to implement the "culture of congestion" to its extreme consequences in both the message and the media, leading to what we have agreed to refer to as "congestive communication”. This concept leads to its inevitable materialisation into an ephemeral, disposable, almost virtual product, because it meets the conditions of a very concrete and specific time, and outside that context it loses its significance. The "culture of congestion" emerged in Koolhaas’ approaches under the guidance of Elia Zenghelis, in the Architectural Association School of Architecture of London. Subsequently, his retroactive manifesto on Manhattan, "Delirious New York" developed it, waging an all-out war against the modern movement urbanism and maintaining that the really contemporary cities are those hyperdense ones that rise as a result of an unplanned development and thanks to the typical technological advances of their time. Finally it began to materialise in the Diploma Unit 9 of the AA, in which he started lecturing in 1975, leaving an indelible mark on subsequent generations of architects who passed that unit. First and foremost, Rem Koolhaas is an intellectual and, therefore, all the theoretical construct in the metropolis began to be reflected in his work through OMA since the beginnings of his production. Broadly speaking, we can say that his career is influenced by two essential historic events, which determine three different stages in his production. In the early years of his career, Koolhaas was still fascinated by the urban metropolis and the implementation of the paranoiac-critical method to his architectural production. He was then a deeply surreal architect. He understood this method as a knowledge strategy and an approach to the world around him: "let the subconscious out but hold it with the crutches of reasonableness”. However, he was actually interested in its implementation on a broad scale, the "Bigness", and therefore, he took part in ambitious projects that led to the accrual of concepts that, beyond being rewarded, left an ideological impression on the evolution of architecture. These projects included his proposal for the Parc de la Villette or the Très Grande Bibliotèque in Paris. The projects he carried out during this period showed a great conceptual background, which evolved into surprising interiors but a sober, or even "povera", exterior appearance, thanks to the use of ephemeral materials that were atypical in the macro-architecture field until that moment. Suddenly, in 1997, the so-called "Bilbao effect" boomed thanks to Frank Gehry (1). The Guggenheim Museum of Bilbao amazed the world with its spectacular nature and its pregnant and impossible shapes. It was the beginning of the era of “The architecture of spectacle”: the transformation of the city through ICONS that would act as nodes of attraction and gathering, around which the economic, cultural and socio-political activity of the city was supposed to be revitalized, as if through a single gesture all internal tissues of the city could be rebuilt. Rem Koolhaas quickly realized that the approach to the city, and especially to the global market, had changed. In the world of globalisation, the only way to get to materialise such "Bigness" was by keeping his intellectual exercises in pregnant, beautiful, iconic and spectacular shapes. Koolhaas found his personal brand in the Stealth aesthetic, resulting from the eighties American combat aircrafts whose shape was faceted in order to avoid radars. Projects such as the Casa da Música in Porto or the Seattle Library date from this period; both buildings are faceted icons of pregnant beauty that left an indelible mark on the city and caused, like the Guggenheim, some degree of recovery and revitalization on the environment in which they were based, at least temporarily. In any case, Koolhaas never gave the merely theoretical exercises up, but he segregated his work in two: OMA produced what was destined to be built and ruled by the parameters of the global market and AMO, Rem’s other side of the mirror, applied the architectural thought in unexplored fields, notwithstanding external agents and being able to work as a purely experimental laboratory. In light of this backdrop, September 11th 2001 came and the attacks on the Twin Towers in New York had devastating effects at all levels, leading to a change in the world order, in a surprisingly short period of time. Rem Koolhaas made a 180° turn directing his vision towards China, where he believed his contributions would have a more direct social benefit than in the Western world. (2) In order to introduce his new course of direction and the creation of the AMO "Think Tank", he planned a major exhibition in the Neue Nationalgalerie of Berlin under the title "Content", in parallel with edition of the book with the same title, which was at first the "exhibition catalog” but, deep down, was always conceived as the most important document of the Office since "SMLXL". However, in many ways it was just the opposite: a publication characterised by its magazine format, soft cover, very fine paging, "supermarket brochure" form and hyperdense content. It was an ephemeral, brief, light, cheap and "disposable" experiment. In fact, it is currently out of stock and out of print. Rem Koolhaas would probably disapprove of a research that sets the spotlight on him, for he would probably say that his validity has expired given that it has been ten years since its publication. However, it shows OMA’s conceptual and vital status at the time of its publication with crystalline clarity and it is also a true milestone in architectural communication. A point of no return. The epitome of the so-called "congestive communication ". This thesis suggests that "Content" contains the essence of Rem Koolhaas’ greatest contribution to the world of architecture: the deep and definitive transformation of architectural communication through the convergence of the conceptual state and the transmission thereof. His architectural and conceptual legacy has left an indelible mark on all subsequent generations. There is no doubt his essays, theories, projects and buildings already belong to the history of architecture. But it is his review on the concept of communication in architecture that has had and shall have an immediate influence on future generations, not only in their communication but also in their architecture, through a bijective exchange. Future approaches should try to determine what happens after "Content", after the maximum hyperdensity, after the visual culture of congestion; what shall Koolhaas suggest as well as what shall happen in the world of architectural communication. To this end, we shall study his latest communication-related projects, such as the design of the Venetian Architecture Biennale in 2014, his intensive research on the "Metabolism" in "Project Japan: Metabolism Talks ...", or the course of his latest territorial approaches in depth. Most recently, Rem Koolhaas has talked about "Preservation", "Sobriety" of "Essentialism", "Performance", etc. The mastermind of the culture of congestion now speaks of the "low density"... as it could not be otherwise, on the other side of the mirror. Summarizing, the white color as the sum of all colors; all wavelengths of the visible spectrum received at the same time.