11 resultados para back to back theatre
em Universidad Politécnica de Madrid
Resumo:
The paper analyses whether that a properly designed multiple choice test can discriminate with a high level of accuracy if a student in our context has reached a B2 level according to the CEFRL.
Resumo:
Recent studies have dealt with the possibility of increasing light absorption by using the so-called electric field enhancement taking place within the grooves of metallic gratings. In order to evaluate the potential improvements derived from the absorption increase, we employ a simplified model to analyze the low-injection behaviour of a solar cell with a metallic grating back-reflector.
Resumo:
One of the key steps to achieve high efficiencies in amorphous/crystalline silicon photovoltaic structures is to design low-ohmic-resistance backcontacts with good passivation in the rear part of the cell. A well known approach to achieve this goal is to use laser-fired contact (LFC) processes in which a metal layer is fired through the dielectric to define good contacts with the semiconductor. However, and despite the fact that this approach has demonstrated to be extremely successful, there is still enough room for process improvement with an appropriate optimization. In this paper, a study focused on the optimal adjustment of the irradiation parameters to produce laser-fired contacts in a-Si:H/c-Si heterojunctionsolarcells is presented. We used samples consisting of crystalline-silicon (c-Si) wafers together with a passivation layer of intrinsic hydrogenated amorphous silicon (a-Si:H(i)) deposited by plasma-enhanced chemical deposition (PECVD). Then, an aluminum layer was evaporated on both sides, the thickness of this layer varied from 0.2 to 1 μm in order to identify the optimal amount of Al required to create an appropriate contact. A q-switched Nd:YVO4laser source, λ = 532 nm, was used to locally fire the aluminum through the thin a-Si:H(i)-layers to form the LFC. The effects of laser fluences were analyzed using a comprehensive morphological and electrical characterization.
Resumo:
A new device structure to improve the performance of concentrator GaAs solar cells is described and the first experimental results are reported. The reason for such an improvement relies on a drastic reduction of the shadowing and series resistance losses based on the possibility of back contacting the emitter region of the solar cell. The experimental results obtained with devices of these types, with a simplified structure, fabricated by liquid phase epitaxy, demonstrate the feasibility and correct operation of the proposed back contact of the emitter of the cells.
Resumo:
Drilling process on wafers to produce EWT or MWT solar cells is a critical fabrication step, which affects on their mechanical stability. The amount of damage introduced during drilling process depends on the density of holes, their size and the chemical process applied afterwards. To quantify the relation between size of the holes and reduction of mechanical strength, several sets of wafers have been prepared, with different hole diameter. The mechanical strength of these sets has been measured by the ring on ring bending test, and the stress state in the moment of failure has been deduced by FE simulation.
Resumo:
Production of back contact solar cells requires holes generations on the wafers to keep both positive and negative contacts on the back side of the cell. This drilling process weakens the wafer mechanically due to the presence of the holes and the damage introduced during the process as microcracks. In this study, several chemical processes have been applied to drilled wafers in order to eliminate or reduce the damage generated during this fabrication step. The treatments analyzed are the followings: alkaline etching during 1, 3 and 5 minutes, acid etching for 2 and 4 minutes and texturisation. To determine mechanical strength of the samples a common mechanical study has been carried out testing the samples by the Ring on Ring bending test and obtaining the stress state in the moment of failure by FE simulation. Finally the results obtained for each treatment were fitted to a three parameter Weibull distribution
Resumo:
Switching of a signal beam by another control beam at different wavelength is demonstrated experimentally using the optical bistability occurring in a 1.55 mm-distributed feedback semiconductor optical amplifier (DFBSOA) working in reflection. Counterclockwise (S-shaped) and reverse (clockwise) bistability are observed in the output of the control and the signal beam respectively, as the power of the input control signal is increased. With this technique an optical signal can be set in either of the optical input wavelengths by appropriate choice of the powers of the input signals. The switching properties of the DFBSOA are studied experimentally as the applied bias current is increased from below to above threshold and for different levels of optical power in the signal beam and different wavelength detunings between both input signals. Higher on-off extinction ratios, wider bistable loops and lower input power requirements for switching are obtained when the DFBSOA is operated slightly above its threshold value.
Resumo:
We propose the Route-back Delivery (RBD) protocol; a routing mechanism to create reverse routes exploiting the Collection Tree Protocol to allow unicast data dissemination from the sink. The main goal of this work is to provide a mechanism to enable bi-directional communications among the root(s) and specific sensor nodes in data gathering applications that does not use broadcast only mechanisms. The main objective of the root-to-remote-nodes route creation is to disseminate short messages to change application parameters in a unicast fashion. This facilitates remote configurability in heterogeneous WSN deployments.
Resumo:
Thinning the absorber layer is one of the possibilities envisaged to further decrease the production costs of Cu(In,Ga)Se2 (CIGSe) thin films solar cell technology. In the present study, the electronic transport in submicron CIGSe-based devices has been investigated and compared to that of standard devices. It is observed that when the absorber is around 0.5 μm-thick, tunnelling enhanced interface recombination dominates, which harms cells energy conversion efficiency. It is also shown that by varying either the properties of the Mo back contact or the characteristics of 3-stage growth processing, one can shift the dominating recombination mechanism from interface to space charge region and thereby improve the cells efficiency. Discussions on these experimental facts led to the conclusions that 3-stage process implies the formation of a CIGSe/CIGSe homo-interface, whose location as well as properties rule the device operation; its influence is enhanced in submicron CIGSe based solar cells.
Resumo:
La obra de Emilio Pérez Piñero que se desarrolla entre los años 1961 y 1972 año en el que muere en un accidente de tráfico volviendo de Figueras, se centra principalmente en artefactos desplegables y desmontables, ejecutando prototipos que en el presente trabajo se han dividido en dos grupos; la cúpula reticular y la infraestructura. No pudo por tanto acudir al Congreso de 1972 de la UIA a recoger el premio Auguste Perret a la innovación tecnológica, que en años anteriores habían recibido Félix Candela, Jean Prouvé, Hans Scharoun o Frei Otto, y que en aquella ocasión tuvo que recoger su viuda. Parámetros como el de la movilidad, indeterminación, intercambiabilidad, obsolescencia y otros que se analizan en el presente trabajo, aparecen a lo largo de toda su obra ya que muchos de sus artefactos están ubicados en no-lugares y tienen un carácter itinerante y por tanto se hace indispensable su rápido montaje y desmontaje, que unas veces se resuelve mediante la desmontabilidad y otras con la plegabilidad de éstos. Aunque pueda parecer Piñero una figura autárquica, lo cierto es que durante la década donde concentra su trabajo se produce una explosión en torno a al arquetipo que será denominado de forma genérica `artefacto´, ligado conceptualmente a los parámetros que aquí se definen. Entendemos artefacto como objeto material realizado por una o varias personas para cumplir una función, es sinónimo de máquina y aparato y deriva de las palabras latinas ars o artis (técnica) y facto (hecho), para designar a los objetos cuya fabricación requiere alguna destreza. El término latino `ars´ engloba a las técnicas y a las artes, lo que no ocurre con el término castellano arte que deriva de él. Los movimientos utópicos que comparte la década con Piñero, utilizan el arquetipo infraestructural, ligero y high tech, para a través de una arquitectura más ligada a la ciencia ficción, realizar una crítica al Movimiento Moderno institucionalizado, todos ellos comparten cierta obsesión por la movilidad, ligada ésta a la idea de espacio flexible, dinámico, nómada. Este concepto de neo-nomadismo, que representa un habitar dinámico, aglutina las nuevas formas de vivir donde la movilidad social y geográfica son habituales. El nomadismo, por otra parte se entiende como sinónimo de democracia y libertad. La arquitectura pasa de ser pesada, estática, permanente a ser un elemento dinámico en continuo movimiento. A veces con connotaciones biológicas se asimilan los artefactos a organismos vivos y les confieren dichas propiedades de crecimiento y autonomía energética, acumulándose en torno a megaestructuras, donde quedan `enchufados´. En este intento de dotar movilidad a lo inmueble, se buscan estructuras vivas y modificables que crecen en una asimilación de las leyes naturales utilizando los parámetros de metamorfosis, simbiosis y cambio. Estos movimientos de vanguardia tienen también ciertas connotaciones políticas y sociales basadas en la libertad y la movilidad y reniegan del consumismo institucionalizado, de la arquitectura como instrumento de consumo, como objeto de usar en la cultura de masas. El carácter político de la autogestión, de la customización como parámetro proyectual, de la autosuficiencia energética, que anticipa la llegada de la crisis energética del año 1973. Objeto de este trabajo será relacionar los conceptos que aparecen fuertemente en el entorno de la década de los años sesenta del siglo XX, en el trabajo de Emilio Pérez Piñero. Parámetros encontrados como conceptos en los grupos de vanguardia y utopía a su vez fuertemente influenciados por las figuras del ingeniero Richard Buckminster Fuller y del arquitecto Konrad Wachsmann. Se analizará que posible influencia tiene la obra de Fuller, principalmente el prototipo denominado cúpula reticular, en la obra de Pérez Piñero y sus coetáneos analizando sus pensamientos teóricos en torno a parámetros como la energía, principalmente en las teorías relativas a Synergetics. El término inventado por Richard B. Fuller es una contracción de otro más largo que en inglés agrupa tres palabras; synergetic-energetic geometry. La definición de sinergia es la cooperación, es decir es el resultado de la acción conjunta de dos o más causas, pero con un efecto superior a la suma de estas causas. El segundo término, energetics geometry, que traducido sería geometría energética hace referencia en primer lugar a la geometría; ya que desarrolla el sistema de referencia que utiliza la naturaleza para construir sus sistemas y en segundo lugar a la energía; ya que además debe ser el sistema que establezca las relaciones más económicas utilizando el mínimo de energía. Por otro lado se analiza la repercusión del prototipo denominado Infraestructura, término acuñado por Yona Friedman y basado estructuralmente y conceptualmente en los desarrollos sobre grandes estructuras de Konrad Wachsmann. El arquitecto alemán divulga su conocimiento en seminarios impartidos por todo el mundo como el que imparte en Tokio y se denomina Wachsmann´s Seminar donde participan algunos de los componentes del grupo Metabolista que sorprenderán al mundo con sus realizaciones en la exposición de Osaka de 1970. El intervalo temporal entre 1961 hasta 1972 hace referencia a la horquilla donde Pérez Piñero realiza su obra arquitectónica, que comienza en 1961 cuando gana el concurso convocado en Londres por la UIA (Unión Internacional de Arquitectos) con el proyecto conocido como Teatro Ambulante, hasta 1972 que es cuando fallece volviendo de Figueras donde está realizando dos encargos de Salvador Dalí; la cubrición del escenario del futuro Teatro-Museo Salvador Dalí y la Vidriera Hipercúbica que debía cerrar la boca de tal escenario. Bajo el título de `Artefactos energéticos. De Fuller a Piñero (1961-1972)´, se presenta esta Tesis doctoral, que tiene la intención de vincular la obra de Emilio Pérez Piñero con la de las neo vanguardias producidas por una serie de arquitectos que operan en el ámbito internacional. Estas vinculaciones se producen de una forma general, donde a través de una serie de estrategias según la metodología que posteriormente se describe se buscan relaciones de la obra del autor español con algunos de los movimientos más significativos que aparecen en dicha década y de manera específica estableciendo relaciones con las obras y pensamientos de los autores que pertenecen a estos movimientos y donde estas relaciones se hacen más evidentes. El objeto del presente trabajo es analizar y explicar la obra del arquitecto Emilio Pérez Piñero, que espacialmente se localiza en el territorio español, desde el punto de vista de estos movimientos para posteriormente poder determinar si existen puntos en común y si el arquitecto español no solo comparte la década temporalmente sino también conceptualmente y por tanto utiliza el ideario que utilizan sus coetáneos que forman parte de las neovanguardias de los años sesenta de siglo XX. ABSTRACT ABSTRACT The Work of Emilio Perez Piñero was developed between the years 1961 and 1972 when he died in a car accident coming back from Figueres, where he was building a geodesic dome to close the building that enclose the Dali’s museum. All his Work is mainly centered in artifact that could be collapsible and removable, taking the two prototypes that are described in this work as a recurrent element in all his creation. These are the reticular dome and the infrastructure that are very influenced by the work from Richard B. Fuller and Konrad Wachsmann. Emilio Pérez Piñero could not receive the Auguste Perret Prize in 1972 awarded by the UIA that years before have received architects as Felix Candela, Jean Prouvé, Hans Scharoun or Frei Otto, and this time Pérez Piñero´s wife will accept it because of his death. Parameters like mobility, changeability, expendability, indetermination and others appear currently in his Work. All the inventions that Piñero had been patented and all of the artifacts that he created are usually located in no-places, because they do have a shifting identity. This kind of building has to be quickly set on site, and this problem has to be solved in term of foldability or demounting. In the decade where his work focuses, an explosion has occurred around this archetype to be generally called artifact that is usually linked to mobility. We understand artifact as a material object made by one or more people to work in a particular way. It is sometimes equated with the terms machinery and apparatus and it is derived from the Latin word `ars´ or `artis´, what means techniques and `facto´ (fact). And we use this term to refer to objects whose manufacture requires the same skill, in fact the Latin word `ars´ covers the techniques and arts, which does not occur with the Castillan term `arte´ that derives from it and means only art. The term neo-nomadic is a relatively new name used for a dynamic life, commonly referred to new forms of life where social and geographical mobility are common. On the other hand nomadic could be understood as a synonymous for democracy and freedom. The architecture is not going to be hard and static anymore but a dynamic element in the move. The Neo-avant-garde movement that shares the decade with Piñero uses this infrastructural archetype, which is light and high-tech, to criticize the institutionalized Modern Movement through architecture linked to science fiction. They all share an obsession with mobility, a concept that is connected to the terms `dynamic´, `nomadic´, `flexibile´, etc. Sometimes, with biological connotations, the utopian assimilate the artifacts to living organisms and give them these properties of growth and energy autonomy, and they apparently grow around megastructures where they are plugged. In this attempt to provide mobility to the inertness, living structures and possibility of change are sought in order to make them grow like a living organism and to assimilate the natural laws of growth. According to a definition from architecture provided by Fernández- Galiano who calls it `exosomatic artifact´, he understand architecture as artifact of the human environment that regulates natural energy flows and channels the energy stored in fuels for the benefit of living beings that inhabit. It is also true that during the sixties a new environmental awareness in public opinion is formed and that is due to the exploitation and disproportionate use of energy resources, acceleration of technological processes and mass consumption. Consequently a new concept is born: energy autonomy, it is very close to rational use of natural energy. Such a concept will be culturally assimilated with the requirement of independence not only in the management but also in the building construction until we arrive at energy autonomy. The individuals become energy consumer, which in turn can enter the energy produced in the system to `life in an eco-mode way´. The objectives of this research are analyzing all of these parameters and concepts that are coming into view in the surrounding of the decade and relate them with the Work of Pérez Piñero. Terms strongly present in the avant-garde movements around the decade, a young architect’s generation strongly influenced by Richard B. Fuller and Konrad Wachsmann. However, it will be analyzed how important the influence of Buckminster Fuller's Work was and his theoretical text about energy on the Work of Pérez Piñero and his fellows of the decade. The term Synergetic was invented by Fuller and came from the words synergy and energetic geometry. Synergy is the cooperation or interaction of two or more agents to produce a greater effect than the sum of their separate effects. Energetic geometry is related to the geometries that the Nature is using to build their construction but always using low energy consumption. On the other hand, the influences from Wachsmann around the prototype called Infrastructure have been analyzed. The German architect has developed knowledge around huge structures that he has spread all around the world through seminars that he has been conducted. One of these was the Wachsmann´s seminar in Tokyo, where same of the members of the Metabolist group were taking part of. Later these young architects will surprise the world with his artifacts at the World Exposition in Osaka in 1970. Between 1961 and 1972 Pérez Piñero produced his architectural work. It began in 1961 when he received the first prize with his project Mobile Theatre in the competition organized by the UIA in London. In 1972 the Auguste Perret Prize was granted by the UIA too. He could not accept it because he died before in a car accident when he was coming from Figueres, when he was designing two projects for Dali. With the title `Energetic Artifacts. From Fuller to Piñero (1961- 1972)´, this thesis relates the Work of Emilio Pérez Piñero with the neo avant-garde made by a young architects’ generation who is sharing the time with him. Several strategies have been used to formed relationships between them. They are described in the present work to set up a method that allows us to relate the work and ideas of the architects of the neo avant-garde with the ones from Piñero. This work is intended to analyze and explained the work of Pérez Piñero from the point of view of the international architects’ generation who is operating at the same time and finally to determinate if Piñero is not sharing the time with them but the concepts, ideas and architectural parameters.