CMOS integration of AlN based piezoelectric microcantilevers

El gran crecimiento de los sistemas MEMS (Micro Electro Mechanical Systems) as�� como su presencia en la mayor��a de los dispositivos que usamos diariamente despert�� nuestro inter��s. Paralelamente, la tecnolog��a CMOS (Complementary Metal Oxide Semiconductor) es la tecnolog��a m��s utilizada para la fabricaci��n de circuitos integrados. Adem��s de ventajas relacionadas con el funcionamiento electr��nico del dispositivo final, la integraci��n de sistemas MEMS en la tecnolog��a CMOS reduce significantemente los costes de fabricaci��n. Algunos de los dispositivos MEMS con mayor variedad de aplicaciones son los microflejes. Estos dispositivos pueden ser utilizados para la extracci��n de energ��a, en microscopios de fuerza at��mica o en sensores, como por ejemplo, para biodetecci��n. Los materiales piezoel��ctricos m��s com��nmente utilizados en aplicaciones MEMS se sintetizan a altas temperaturas y por lo tanto no son compatibles con la tecnolog��a CMOS. En nuestro caso hemos usado nitruro de alumino (AlN), que se deposita a temperatura ambiente y es compatible con la tecnolog��a CMOS. Adem��s, es biocompatible, y por tanto podr��a formar parte de un dispositivo que act��e como biosensor. A lo largo de esta tesis hemos prestado especial atenci��n en desarrollar un proceso de fabricaci��n r��pido, reproducible y de bajo coste. Para ello, todos los pasos de fabricaci��n han sido minuciosamente optimizados. Los par��metros de sputtering para depositar el AlN, las distintas t��cnicas y recetas de ataque, los materiales que act��an como electrodos o las capas sacrificiales para liberar los flejes son algunos de los factores clave estudiados en este trabajo. Una vez que la fabricaci��n de los microflejes de AlN ha sido optimizada, fueron medidos para caracterizar sus propiedades piezoel��ctricas y finalmente verificar positivamente su viabilidad como dispositivos piezoel��ctricos. ABSTRACT The huge growth of MEMS (Micro Electro Mechanical Systems) as well as their presence in most of our daily used devices aroused our interest on them. At the same time, CMOS (Complementary Metal Oxide Semiconductor) technology is the most popular technology for integrated circuits. In addition to advantages related with the electronics operation of the final device, the integration of MEMS with CMOS technology reduces the manufacturing costs significantly. Some of the MEMS devices with a wider variety of applications are the microcantilevers. These devices can be used for energy harvesting, in an atomic force microscopes or as sensors, as for example, for biodetection. Most of the piezoelectric materials used for these MEMS applications are synthesized at high temperature and consequently are not compatible with CMOS technology. In our case we have used aluminum nitride (AlN), which is deposited at room temperature and hence fully compatible with CMOS technology. Otherwise, it is biocompatible and and can be used to compose a biosensing device. During this thesis work we have specially focused our attention in developing a high throughput, reproducible and low cost fabrication process. All the manufacturing process steps of have been thoroughly optimized in order to achieve this goal. Sputtering parameters to synthesize AlN, different techniques and etching recipes, electrode material and sacrificial layers are some of the key factors studied in this work to develop the manufacturing process. Once the AlN microcantilevers fabrication was optimized, they were measured to characterize their piezoelectric properties and to successfully check their viability as piezoelectric devices.

Estrategias de desarrollo sostenible de la arquitectura del oasis de M���hamid, desierto del Sahara

Esta investigaci��n se plantea con la hip��tesis radical de c��mo habitar el desierto de forma sostenible, desde una actitud pragm��tica y experimental basada en el progreso. La justificaci��n se basa en primer lugar en los 2.000 millones de personas en el mundo que viven en entornos des��rticos, el 80% de ellas, en pa��ses en desarrollo, porque el 40% de la superficie terrestre est�� bajo amenaza de desertificaci��n afectando al 37% de la poblaci��n mundial, con 12 millones de hect��reas al a��o perdidas por esa causa, y por ��ltimo, porque se considera el desierto como un entorno de gran atractivo y potencial. El contenido de la investigaci��n se estructura en tres movimientos: posicionamiento, mirada y acci��n: Desde el posicionamiento se define en primer lugar la sostenibilidad, aportando un nuevo diagrama donde se incorpora el ��mbito arquitect��nico como uno de los pilares principales, y, posteriormente, se establecen los criterios de evaluaci��n de la sostenibilidad, aportando un sistema de indicadores donde se incorporan par��metros adecuados a las circunstancias del oasis. Del mismo modo, se estudian y analizan metodolog��as de actuaci��n y proyectos de desarrollo sostenible existentes que enmarcan el estado del arte, constatando la dificultad de adaptaci��n de los mismos a las condiciones de los oasis, por lo que se elabora una metodolog��a propia donde se modifica la din��mica estrat��gica, de forma que el impulso se plantea desde la acci��n social, a trav��s de hip��tesis de estrategias basadas en sistemas low-cost, autoconstruidas, asumibles econ��micamente y de implantaci��n factible. El caso de estudio espec��fico radica en la situaci��n extrema de las condiciones en el oasis de M���hamid, donde se evidencia un proceso de desintegraci��n y abandono. Esto es debido a una acumulaci��n de circunstancias externas e internas, de m��ltiples factores: naturales y antr��picos que afectan al oasis, llevando al extremo las condiciones clim��ticas y la escasez de recursos, naturales y artificiales. Factores como el cambio clim��tico, la sequ��a, los cambios en las pol��ticas del agua, la amenaza de desertificaci��n, los conflictos sociales, el desequilibrio ecol��gico, la escasez econ��mica, la crisis energ��tica, la obsolescencia arquitect��nica, el patrimonio construido pr��cticamente destruido, y la malentendida nueva arquitectura. Es importante constatar la escasa documentaci��n gr��fica existente sobre la zona de actuaci��n lo que ha conllevado un amplio trabajo de documentaci��n, tanto cartogr��fica como de observaci��n directa, aportada a la tesis como investigaci��n de elaboraci��n propia. La mirada anal��tica al caso de estudio permite conocer los recursos disponibles y las potencialidades latentes del oasis de M���hamid, que permitir��n actuar para subvertir la din��mica involutiva imperante, de forma que los dibujos iniciales de apropiaci��n contextual y an��lisis cr��ticos derivan en mapas de acci��n diagramados conformados por un sistema de objetos y la definici��n de estrategias transversales, deconstruyendo el pasado y reconstruyendo el futuro, incorporando sistemas alternativos que se definen en 7 l��neas estrat��gicas de acci��n formuladas desde los 3 ��mbitos relacionados con el ecosistema: ecol��gico, socio- econ��mico y arquitect��nico. As��, la tesis defiende la acci��n arquitect��nica como impulsora del desarrollo sostenible, apoyada en 3 elementos: - la creaci��n de objetos ���tecnoartesanos���, para el aprovechamiento de los recursos energ��ticos - las transformaciones arquitect��nicas, para reformular el h��bitat desde la eficiencia energ��tica y el progreso - y el impulso de acciones cotidianas, que redefinan las relaciones sociales, creando entornos cooperativos y colaborativos. En el ��mbito ecol��gico se proponen actuaciones anti desertificaci��n mediante incubadoras de ��rboles; sistemas alternativos de gesti��n del agua, como la lluvia s��lida; estrategias de potenciaci��n de la producci��n agr��cola; la construcci��n de mecanismos de obtenci��n de energ��a a partir de residuos, como los paneles solares con botellas PET. En el ��mbito socioecon��mico se plantean nuevas formas de acci��n social y de reactivaci��n econ��mica. Por ��ltimo, en el ��mbito urbano-arquitect��nico, se incorporan modificaciones morfol��gicas a la arquitectura existente y una relectura contempor��nea de la tierra, como material que permite nuevas geometr��as, obteniendo arena petrificada por procesos microbiol��gicos, y potenciando la tierra como recurso art��stico. Esta tesis es un punto de partida, recoge sistemas, estrategias y experiencias, para funcionar como un est��mulo o impulso dinamizador del futuro desarrollo sostenible del oasis, abriendo v��as de investigaci��n y experimentaci��n. ABSTRACT This research puts forth the radical hypothesis of how to inhabit the desert in a sustainable way, using a pragmatic and experimental approach based on progress. The justification for this resides in the fact that there are 2,000 million people in the world living in desert environments, 80% of them in developing countries. Forty percent of the earth���s surface is under threat of desertification, affecting 37% of the world population and with 12 million hectares being lost each year. And finally, the desert is considered as an attractive environment and therefore, with great potential. The content of the research is structured in three main sections: positioning, observation and action: As a point of departure, sustainability is defined, proposing a new framework where architecture is incorporated as one of the main pillars. Then, the criteria for evaluating sustainability are established. These provide a system of indicators, which incorporate parameters based on the specific circumstances of the oasis. Methodologies and existing sustainable development projects that represent the state-of-the-art are analyzed, discussing the difficulty of adapting them to conditions of oases. A methodology that modifies strategic concepts is developed, whereby the catalyst is social action, and strategies are developed based on low-cost, self-built, and feasible implementation systems. The specific case study lies in the extreme conditions in the oasis of M'hamid, where a process of decay and neglect is evident. This deterioration is due to an accumulation of external and internal circumstances, and of natural and anthropogenic factors that affect the oasis, leading to extreme weather conditions and a shortage of both natural and artificial resources. Factors include; climate change, drought, changes in water policies, the threat of desertification, social conflicts, ecological imbalance, economic shortage, the energy crisis, architectural obsolescence, destruction of built heritage, and misunderstood new architecture. It is important to note the extremely limited graphic information about the area has led me to produce an extensive archive of maps and drawings, many developed by direct observation, that contribute to the research. The case study analysis of the oasis of M'hamid examines the resources available and the latent potential to slow the prevailing trend towards deterioration. The initial drawings of contextual appropriation and critical analysis result in maps and diagrams of action, which are formed by a system of objects and the definition of strategies. These can be thought of as understanding or ���deconstructing��� the past to reconstruct the future. Alternative approaches defined in seven strategies for action are based on three fields related to the ecosystem: ecological, socioeconomic and architectural. Thus, the thesis defends architectural action to promote sustainable development, based on three elements: - The creation of "techno-artisans", to make use of energy resources - Architectural changes, to reformulate habitat in terms of energy efficiency and progress - And the promotion of everyday actions, to redefine social relations, creating cooperative and collaborative environments. In the ecological field, I propose anti-desertification actions such as; tree incubators, alternative water management systems(such as solid rain),; strategies to empower the agricultural production, energy from low-cost systems made out from recycled materials(such as solar panels from PET bottles or wind turbine from bicycle wheels). In the socioeconomic sphere, I propose to implement new forms of social action and economic regeneration. Finally, within the urban and architectural field, I propose morphological changes to the existing architecture and a contemporary reinterpretation of the earth as a material that allows new geometries, creating petrified sand by microbiological processes or enhancing nature as an artistic and energy resource. This thesis is a starting point. It collects systems, strategies and experiences to serve as a stimulus or dynamic momentum for future sustainable development of the oasis, opening new avenues of research and experimentation. R��SUM�� Cette recherche part d'une hypoth��se radicale : comment habiter le d��sert de fa��on durable, et ce �� partir d'une approche pragmatique et exp��rimentale bas��e sur le progr��s. Cette hypoth��se se justifie en raison des 2 milliards de personnes qui dans le monde habitent des environnements d��sertiques, 80% d'entre eux dans des pays en voie de d��veloppement, mais aussi parce que 40% de la surface de la plan��te est sous menace de d��sertification, un ph��nom��ne affectant 37% de la population mondiale et qui cause la perte de 12 millions d'hectares par an; et enfin parce que le d��sert est consid��r�� comme un environnement tr��s attrayant et fort d���un grand potentiel. Le contenu de la recherche se divise en trois mouvements: le positionnement, le regard et l'action : Du point de vue du positionnement on d��finit tout d'abord la durabilit��, pr��sentant un nouveau sch��ma o�� le domaine de l'architecture devient un des principaux piliers, et, par la suite, des crit��res d'��valuation de la durabilit�� sont ��tablis, en fournissant un syst��me d���indicateurs qui int��gre les param��tres appropri��s aux circonstances de l'oasis. De m��me, des m��thodologies et des projets de d��veloppement durable existants sont ��tudi��s et analys��s, ce qui encadre l'��tat de l'art, remarquant la difficult�� de les adapter aux conditions des oasis. De cette difficult�� d��coule l'��laboration d'une m��thodologie qui modifie la dynamique strat��gique, de sorte que l'impulsion provient de l'action sociale, �� travers des hypoth��ses de strat��gie bas��es sur des syst��mes low-cost, auto-construits, et de mise en oeuvre ��conomiquement viable. Le cas d'��tude sp��cifique r��side en la situation extr��me des conditions de l'oasis de M���hamid, o�� un processus de d��cadence et de n��gligence est ��vident. Cela est d�� �� une accumulation de circonstances externes et internes, de multiples facteurs: les facteurs naturels et anthropiques qui affectent l'oasis, menant �� l'extr��me les conditions m��t��orologiques et la p��nurie de ressources, autant naturelles qu'artificielles. Des facteurs tels que le changement climatique, la s��cheresse, les changements dans les politiques de l'eau, la menace de la d��sertification, les conflits sociaux, le d��s��quilibre ��cologique, la p��nurie ��conomique, la crise de l'��nergie, l'obsolescence architecturale, le patrimoine b��ti pratiquement d��truit et une mauvais compr��hensif de la nouvelle architecture. Il est important de de faire remarquer le peu d'informations graphiques du domaine d'action, ce qui a conduit �� un vaste travail de documentation, autant cartographique que relative �� l'observation directe. Cette documentation s'ajoute �� la th��se en tant que recherche propre. Le regard analytique sur le cas d'��tude permet de conna��tre les ressources disponibles et le potentiel latent de l'oasis de M���hamid, qui agiront pour renverser la dynamique d'involution en vigueur. Ainsi, les premiers dessins d'appropriation contextuelle et analyse critique deviennent des cartes d'action sch��matis��es form��es par un syst��me d'objets et la d��finition de strat��gies transversales, qui d��construisent le pass�� et reconstruisent l'avenir, en incorporant des syst��mes alternatifs qui se d��finissent sur 7 lignes strat��giques d'action formul��es �� partir des 3 domaines en relation avec l�����cosyst��me: l�����cologique, le socio-��conomique et l'architectural. Ainsi, la th��se d��fend l'action architecturale en tant que promotrice du d��veloppement durable, et ce bas�� sur 3 ��l��ments: - la cr��ation d'objets "technoartisans" pour l'exploitation des ressources ��nerg��tiques - les modifications architecturales, pour reformuler l'habitat du point de vue de l'efficacit�� ��nerg��tique et le progr��s - et la promotion des actions quotidiennes, pour red��finir les relations sociales, et la cr��ation d'environnements de coop��ration et collaboration. Dans le domaine de l'��cologie des actions de lutte contre la d��sertification sont propos��es �� travers des p��pini��res d'arbres, des syst��mes alternatifs de gestion de l'eau comme par exemple la pluie solide, des strat��gies de mise en valeur de la production agricole, la construction de m��canismes de production d'��nergie �� partir de r��sidus, tels que les panneaux solaires ou les bouteilles en PET. Dans le domaine socio-��conomique, l'on propose de nouvelles formes d'action sociale et de reprise ��conomique. Enfin, dans le domaine de l'urbain et de l'architectural, on incorpore des changements morphologiques �� l'architecture existante et une relecture contemporaine de la terre, comme mat��riau qui permet de nouvelles g��om��tries, en obtenant du sable p��trifi�� par des proc��d��s microbiologiques et en mettant en valeur la terre comme une ressource artistique. Cette th��se n'est qu'un point de d��part. Elle recueille des syst��mes, des strat��gies et des exp��riences pour servir de stimulus ou d'impulsion dynamisatrice du futur d��veloppement durable de l'oasis, en ouvrant des voies de recherche et d'exp��rimentation.

Aerodin��mica experimental de elementos de parques energ��ticos

La creciente demanda de energ��a el��ctrica y la necesidad de implementar energ��as no contaminantes hace que las llamadas tecnolog��as verdes sean cada d��a m��s solicitadas. Entre estas tecnolog��as encontramos la energ��a solar y la energ��a e��lica; ambas tienen una trayectoria de uso e investigaci��n bastante amplia, sin embargo a��n presentan problemas de fondo que impiden dar mayor impulso a su uso. El objetivo de la presente tesis es presentar soluciones a problemas de optimizaci��n en campos conversores de energ��a. Para ello se analizan y resuelven dos problemas por medio de t��cnicas de aerodin��mica experimental: el primero sobre campos de colectores solares y el segundo sobre campos e��licos. Las t��cnicas de medici��n utilizadas en aerodin��mica, y en el presente trabajo, son: medici��n de cargas, anemometr��a de hilo caliente, velocimetr��a por imagen de part��culas y escaneo de presiones; adem��s de un an��lisis estad��stico de los datos. En el primer caso se ensayan experimentalmente colectores solares parab��licos en donde, por cuestiones de seguridad o por protecci��n contra el viento, se utilizan cercas. ��stas modifican el comportamiento del flujo corriente abajo y se ha encontrado que la distancia a la cual se colocan, as�� como el tipo de cercas (s��lida o permeable), modifican las cargas estructurales a las que los colectores est��n expuestos. Los resultados demuestran que existe una distancia cr��tica en la cual la presencia de la cerca aumenta la carga en lugar de disminuirla, por lo cual la selecci��n adecuada del parapeto y la distancia a la cual se coloca son de suma importancia para la optimizaci��n de la estructura. En el segundo caso se ensaya experimentalmente y simula num��ricamente la estela de turbinas e��licas por medio de discos porosos. En donde un disco permeable simula el rotor de una turbina. El disco es capaz de semejar la estela y los efectos que ��sta puede causar corriente abajo. Los resultados muestran que seleccionando adecuadamente la porosidad, es posible simular coeficientes de empuje similares a los desarrollados por los aerogeneradores, adem��s la estela y sus efectos son semejantes a los medidos en campo. ABSTRACT The called green energy technologies are increasingly required because of the growing demand for electricity and the need to implement nonpolluting energy. Among the green energy technologies it is found the solar and the wind energy, both have a history of use and fairly extensive research; however they still have problems which limit to give them further impetus to its use. The aim of this thesis is to present solutions to optimization problems in energy harvesting. To this end it is analysed, and solved, two problems by means of techniques in experimental aerodynamics: the first issue with regard to parabolic troughs and the second about wind farms. The measurement techniques commonly used in aerodynamics, and used in this research work, are: measurement of loads, hot wire anemometry, particle image velocimetry and scanning of pressures; where data are collected and then an statistical analysis is done. In the first case it is tested parabolic troughs where, either for security reasons or protection against the wind actions, fences are used. These fences modify the behaviour of flow downstream and it was found that the distance at which they are placed, and the type of fences (solid or permeable) modify the structural loads to which the parabolic troughs are exposed. The results show that there is a critical distance at which the presence of the fence increases the load instead of protecting the parabolic trough, hence making the proper selection of the parapet and the distance at which it stands are paramount for the optimization of the structure. In the second case it is tested, experimentally and numerically, the wake of wind turbines by means of porous disks; where the permeable disc simulates a turbine rotor. The disc is able to mimic the wake and the effects that it can cause downstream. The results show that by properly selecting the porosity, it is possible to simulate drag coefficients similar to those developed by wind turbines; moreover the porous disk wake and its effects are similar to those measured on field.

La implementaci��n arquitect��nica de los acristalamientos activos con agua circulante, y su contribuci��n en edificios de consumo de energ��a casi nulo

La presente Tesis Doctoral eval��a la contribuci��n de una fachada activa, constituida por acristalamientos con circulaci��n de agua, en el rendimiento energ��tico del edificio. Con especial ��nfasis en la baja afecci��n sobre su imagen, su integraci��n ha de favorecer la calificaci��n del edificio con el futuro est��ndar de Edificio de consumo de Energ��a Casi Nulo (EECN). El prop��sito consiste en cuantificar su aportaci��n a limitar la demanda de climatizaci��n, como soluci��n de fachada transparente acorde a las normas de la energ��a del 2020. En el primer cap��tulo se introduce el planteamiento del problema. En el segundo cap��tulo se desarrollan la hip��tesis y el objetivo fundamental de la investigaci��n. Para tal fin, en el tercer cap��tulo, se revisa el estado del arte de la tecnolog��a y de la investigaci��n cient��fica, mediante el an��lisis de la literatura de referencia. Se comparan patentes, prototipos, sistemas comerciales asimilables, investigaciones en curso en Universidades, y proyectos de investigaci��n y desarrollo, sobre envolventes que incorporan acristalamientos con circulaci��n de agua. El m��todo experimental, expuesto en el cuarto cap��tulo, acomete el dise��o, la fabricaci��n y la monitorizaci��n de un prototipo expuesto, durante ciclos de ensayos, a las condiciones clim��ticas de Madrid. Esta fase ha permitido adquirir informaci��n precisa sobre el rendimiento del acristalamiento en cada orientaci��n de incidencia solar, en las distintas estaciones del a��o. En paralelo, se aborda el desarrollo de modelos te��ricos que, mediante su asimilaci��n a soluciones multicapa caracterizadas en las herramientas de simulaci��n EnergyPlus y IDA-ICE (IDA Indoor Climate and Energy), reproducen el efecto experimental. En el quinto cap��tulo se discuten los resultados experimentales y te��ricos, y se analiza la respuesta del acristalamiento asociado a un determinado volumen y temperatura del agua. Se calcula la eficiencia en la captaci��n de la radiaci��n y, mediante la comparativa con un acristalamiento convencional, se determina la reducci��n de las ganancias solares y las p��rdidas de energ��a. Se comparan el rendimiento del acristalamiento, obtenido experimentalmente, con el ofrecido por paneles solares fotot��rmicos disponibles en el mercado. Mediante la traslaci��n de los resultados experimentales a casos de c��lulas de tama��o habitable, se cuantifica la afecci��n del acristalamiento sobre el consumo en refrigeraci��n y calefacci��n. Diferenciando cada caso por su composici��n constructiva y orientaci��n, se extraen conclusiones sobre la reducci��n del gasto en climatizaci��n, en condiciones de bienestar. Posteriormente, se eval��a el ahorro de su incorporaci��n en un recinto existente, de construcci��n ligera, localizado en la Escuela de Arquitectura de la Universidad Polit��cnica de Madrid (UPM). Mediante el planteamiento de escenarios de rehabilitaci��n energ��tica, se estima su compatibilidad con un sistema de climatizaci��n mediante bomba de calor y extracci��n geot��rmica. Se describe el funcionamiento del sistema, desde la perspectiva de la operaci��n conjunta de los acristalamientos activos e intercambio geot��rmico, en nuestro clima. Mediante la parametrizaci��n de sus funciones, se estima el beneficio adicional de su integraci��n, a partir de la mejora del rendimiento de la bomba de calor COP (Coefficient of Performance) en calefacci��n, y de la eficiencia EER (Energy Efficiency Ratio) en refrigeraci��n. En el recinto de la ETSAM, se ha analizado la contribuci��n de la fachada activa en su calificaci��n como Edificio de Energ��a Casi Nula, y estudiado la rentabilidad econ��mica del sistema. En el sexto cap��tulo se exponen las conclusiones de la investigaci��n. A la fecha, el sistema supone alta inversi��n inicial, no obstante, genera elevada eficiencia con bajo impacto arquitect��nico, reduci��ndose los costes operativos, y el dimensionado de los sistemas de producci��n, de mayor afecci��n sobre el edificio. Mediante la envolvente activa con suministro geot��rmico no se condena la superficie de cubierta, no se ocupa volumen ��til por la presencia de equipos emisores, y no se reduce la superficie o altura ��til a base de reforzar los aislamientos. Tras su discusi��n, se considera una alternativa de valor en procesos de dise��o y construcci��n de Edificios de Energ��a Casi Nulo. Se proponen l��neas de futuras investigaci��n cuyo prop��sito sea el conocimiento de la tecnolog��a de los acristalamientos activos. En el ��ltimo cap��tulo se presentan las actividades de difusi��n de la investigaci��n. Adicionalmente se ha proporcionado una mejora tecnol��gica a las fachadas activas existentes, que ha derivado en la solicitud de una patente, actualmente en tramitaci��n. ABSTRACT This Thesis evaluates the contribution of an active water flow glazing fa��ade on the energy performance of buildings. Special emphasis is made on the low visual impact on its image, and the active glazing implementation has to encourage the qualification of the building with the future standard of Nearly Zero Energy Building (nZEB). The purpose is to quantify the fa��ade system contribution to limit air conditioning demand, resulting in a transparent fa��ade solution according to the 2020 energy legislation. An initial approach to the problem is presented in first chapter. The second chapter develops the hypothesis and the main objective of the research. To achieve this purpose, the third chapter reviews the state of the art of the technology and scientific research, through the analysis of reference literature. Patents, prototypes, assimilable commercial systems, ongoing research in other universities, and finally research and development projects incorporating active fluid flow glazing are compared. The experimental method, presented in fourth chapter, undertakes the design, manufacture and monitoring of a water flow glazing prototype exposed during test cycles to weather conditions in Madrid. This phase allowed the acquisition of accurate information on the performance of water flow glazing on each orientation of solar incidence, during different seasons. In parallel, the development of theoretical models is addressed which, through the assimilation to multilayer solutions characterized in the simulation tools EnergyPlus and IDA-Indoor Climate and Energy, reproduce the experimental effect. Fifth chapter discusses experimental and theoretical results focused to the analysis of the active glazing behavior, associated with a specific volume and water flow temperature. The efficiency on harvesting incident solar radiation is calculated, and, by comparison with a conventional glazing, the reduction of solar gains and energy losses are determined. The experimental performance of fluid flow glazing against the one offered by photothermal solar panels available on the market are compared. By translating the experimental and theoretical results to cases of full-size cells, the reduction in cooling and heating consumption achieved by active fluid glazing is quantified. The reduction of energy costs to achieve comfort conditions is calculated, differentiating each case by its whole construction composition and orientation. Subsequently, the saving of the implementation of the system on an existing lightweight construction enclosure, located in the School of Architecture at the Polytechnic University of Madrid (UPM), is then calculated. The compatibility between the active fluid flow glazing and a heat pump with geothermal heat supply system is estimated through the approach of different energy renovation scenarios. The overall system operation is described, from the perspective of active glazing and geothermal heat exchange combined operation, in our climate. By parameterization of its functions, the added benefit of its integration it is discussed, particularly from the improvement of the heat pump performance COP (Coefficient of Performance) in heating and efficiency EER (Energy Efficiency Ratio) in cooling. In the case study of the enclosure in the School of Architecture, the contribution of the active glazing fa��ade in qualifying the enclosure as nearly Zero Energy Building has been analyzed, and the feasibility and profitability of the system are studied. The sixth chapter sets the conclusions of the investigation. To date, the system may require high initial investment; however, high efficiency with low architectural impact is generated. Operational costs are highly reduced as well as the size and complexity of the energy production systems, which normally have huge visual impact on buildings. By the active fa��ade with geothermal supply, the deck area it is not condemned. Useful volume is not consumed by the presence of air-conditioning equipment. Useful surface and room height are not reduced by insulation reinforcement. After discussion, water flow glazing is considered a potential value alternative in nZEB design and construction processes. Finally, this chapter proposes future research lines aiming to increase the knowledge of active water flow glazing technology. The last chapter presents research dissemination activities. Additionally, a technological improvement to existing active facades has been developed, which has resulted in a patent application, currently in handling process.

Multiscale assessment of patterns of avian species richness

The search for a common cause of species richness gradients has spawned more than 100 explanatory hypotheses in just the past two decades. Despite recent conceptual advances, further refinement of the most plausible models has been stifled by the difficulty of compiling high-resolution databases at continental scales. We used a database of the geographic ranges of 2,869 species of birds breeding in South America (nearly a third of the world's living avian species) to explore the influence of climate, quadrat area, ecosystem diversity, and topography on species richness gradients at 10 spatial scales (quadrat area, ���12,300 to ���1,225,000 km2). Topography, precipitation, topography �� latitude, ecosystem diversity, and cloud cover emerged as the most important predictors of regional variability of species richness in regression models incorporating 16 independent variables, although ranking of variables depended on spatial scale. Direct measures of ambient energy such as mean and maximum temperature were of ancillary importance. Species richness values for 1�� �� 1�� latitude-longitude quadrats in the Andes (peaking at 845 species) were ���30���250% greater than those recorded at equivalent latitudes in the central Amazon basin. These findings reflect the extraordinary abundance of species associated with humid montane regions at equatorial latitudes and the importance of orography in avian speciation. In a broader context, our data reinforce the hypothesis that terrestrial species richness from the equator to the poles is ultimately governed by a synergism between climate and coarse-scale topographic heterogeneity.

Evolutionary relationships of the coelacanth, lungfishes, and tetrapods based on the 28S ribosomal RNA gene.

The origin of land vertebrates was one of the major transitions in the history of vertebrates. Yet, despite many studies that are based on either morphology or molecules, the phylogenetic relationships among tetrapods and the other two living groups of lobe-finned fishes, the coelacanth and the lungfishes, are still unresolved and debated. Knowledge of the relationships among these lineages, which originated back in the Devonian, has profound implications for the reconstruction of the evolutionary scenario of the conquest of land. We collected the largest molecular data set on this issue so far, about 3,500 base pairs from seven species of the large 28S nuclear ribosomal gene. All phylogenetic analyses (maximum parsimony, neighbor-joining, and maximum likelihood) point toward the hypothesis that lungfishes and coelacanths form a monophyletic group and are equally closely related to land vertebrates. This evolutionary hypothesis complicates the identification of morphological or physiological preadaptations that might have permitted the common ancestor of tetrapods to colonize land. This is because the reconstruction of its ancestral conditions would be hindered by the difficulty to separate uniquely derived characters from shared derived characters in the coelacanth/lungfish and tetrapod lineages. This molecular phylogeny aids in the reconstruction of morphological evolutionary steps by providing a framework; however, only paleontological evidence can determine the sequence of morphological acquisitions that allowed lobe-finned fishes to colonize land.

Responsivity and resonant properties of dipole, bowtie, and spiral Seebeck nanoantennas

Seebeck nanoantennas, which are based on the thermoelectric effect, have been proposed for electromagnetic energy harvesting and infrared detection. The responsivity and frequency dependence of three types of Seebeck nanoantennas is obtained by electromagnetic simulation for different materials. Results show that the square spiral antenna has the widest bandwidth and the highest induced current of the three analyzed geometries. However, the geometry that presented the highest temperature gradient was the bowtie antenna, which favors the thermoelectric effect in a Seebeck nanoantenna. The results also show that these types of devices can present a voltage responsivity as high as 36��������V/W36��������V/W for titanium���nickel dipoles resonant at far-infrared wavelengths.

Geothermal Electricity Generation in Colorado: Actual and Perceived Obstacles to Greater Implementation

The objective of this paper is to provide an analysis of the potential and obstacles to the development of geothermal energy resources in Colorado. Geothermal energy is the only renewable resource that can provide base-load electricity. While Colorado has significant geothermal energy potential, there are no such power plants. Layers of federal and state laws and regulations represent one barrier to further geothermal development. Transmission constraints represent another major barrier. High exploration and construction costs along with high-risk profiles for geothermal projects form another major barrier. Perceived barriers such as misunderstanding the impacts, risks, and benefits of geothermal energy hinder further development. Recommendations are provided to help overcome these obstacles.

Physical and chemical evaluation of furniture waste briquettes

Furniture waste is mainly composed of wood and upholstery foam (mostly polyurethane foam). Both of these have a high calorific value, therefore, energy recovery would be an appropriate process to manage these wastes. Nevertheless, the drawback is that the energy content of these wastes is limited due to their low density mainly that of upholstery foam. Densification of separate foam presents difficulties due to its elastic character. The significance of this work lies in obtaining densified material by co-densification of furniture wood waste and polyurethane foam waste. Densification of furniture wood and the co-densification of furniture wood waste with polyurethane foam have been studied. On the one hand, the parameters that have an effect on the quality of the furniture waste briquettes have been analysed, i.e., moisture content, compaction pressure, presence of lignin, etc. The maximum weight percentage of polyurethane foam that can be added with furniture wood waste to obtain durable briquettes and the optimal moisture were determined. On the other hand, some parameters were analysed in order to evaluate the possible effect on the combustion. The chemical composition of waste wood was compared with untreated wood biomass; the higher nitrogen content and the concentration of some metals were the most important differences, with a significant difference of Ti content.

DAS GESPR��CH ZWISCHEN H��LDERLIN, HEGEL UND SCHELLING ��BER KANTS ANTINOMIEN

��Die Art, wie er den Mechanismus der Natur mit ihrer Zweckm����igkeit vereiniget, scheint mir eigentlich den ganzen Geist seines Systems zu enthalten��: This quotation, which originated the present essay, is solely extracted from a letter sent by H��lderlin to Hegel, and yet, it condensates three different approaches from the three T��bingen friends to the problem of Kant���s philosophy of religion and to its possible resolution between 1795 and 1796. From this epistolary dialogue emerges a simultaneous study of Kant, originated by the growing dissension towards the orthodox thought of the Stift. The turning point ��� or the maximum cumulative point ��� of this discordance happens precisely with the discovery of the ��spirit of Kant���s system��, as a combined explanation of the religious and philosophical phenomena [��Die Art, wie er den Mechanismus der Natur mit ihrer Zweckm��ssigkeit vereiniget��]. This, I think, is something which the three friends discover gradually and not independently from the concept of ��providence��, which Kant himself, according to H��lderlin, had used to ��attenuate his antinomies��, which Hegel uses in his first religious writings and the initial formation of his own philosophy and which Schelling will later explore in his System of Transcendental Idealism. In a word, providence is consensually the comprehension axis between man, God and nature and, thus, the explanatory link between the antinomical poles which regulate human existence. On the other hand, however ��� this being the aspect I would like to stress ���, this decisive moment for a whole generation, for the history of philosophy itself, means the consummation of a new revolutionary perspective born in Kant, a new vision of the absolute and the divine and, therefore, a new way to write philosophy about philosophy, less philosophical than before, to the extent that the new situation of man and his reflection within the problem ultimately destined them ��� as is the case in the three young philosophers ��� to silence and death. The final aim of this essay is, therefore, to know what this ��last step of philosophy�� is and what dies along with it, what such a step may have meant and what it already foretold in terms of the development of philosophy.

Water resources appraisal for hydroelectric licensing : Skagit River basin, Washington.

Aug. 1980.

Final environmental impact statement : Sultan River project, FERC no. 2157--Washington.

"FERC/EIS-0015"--Cover.

PWR fuel element specifications.

"Reactors - Power (TID-4500, 13th Edition)."

Microstructural evaluation of superheat cladding materials /

"U.S. Atomic Energy Commission Contract AT(04-3)-189, Project agreement 13."

Prattsville Pumped Storage Project, No. 2729, New York : final environmental impact statement.

"Applicant: Power Authority of the State of New York."