Mechanical Characterization of Multicrystalline Silicon Substrates for Solar Cell Applications

The possibility of using more economical silicon feedstock, i.e. as support for epitaxial solar cells, is of interest when the cost reduction and the properties are attractive. We have investigated the mechanical behaviour of two blocks of upgraded metallurgical silicon, which is known to present high content of impurities even after being purified by the directional solidification process. These impurities are mainly metals like Al and silicon compounds. Thus, it is important to characterize their effect in order to improve cell performance and to ensure the survival of the wafers throughout the solar value chain. Microstructure and mechanical properties were studied by means of ring on ring and three point bending tests. Additionally, elastic modulus and fracture toughness were measured. These results showed that it is possible to obtain marked improvements in toughness when impurities act as microscopic internal crack arrestors. However, the same impurities can be initiators of damage due to residual thermal stresses introduced during the crystallization process.

Simulation of the transmission performance for equalized holographic ROADM designs

A complete simulation of the transmission performance for Equalized Holographic ROADM (Reconfigurable Optical Add-Drop Multiplexer) designs is presented in this paper. These devices can address several wavelengths from the input to different output fibres, according to the holograms stored in a SLM (Spatial Light Modulator), where all the outputs are equalized in power. All combinations of the input wavelengths are possible at the different output fibres. To simulate the transmission performance of the EH-ROADM, a software program, from Optiwave, has been used. The correspondence between physical blocks of the device (grating, SLM, lens...) and those simulated in the program (filters, losses, splitters...) has been defined in order to obtain a close agreement between the theoretical transmission performance and the simulated one. To complete the review about Equalized Holographic ROADMs some guidelines about its design have been done.

Stabilization of hillside in the work terraces of Alcaidesa in San Roque(C��diz)

In the locality of The Hills of Alcaidesa in San Roque (C��diz) has been constructed three blocks of housing called "The Terraces Alcaidesa" in a hillside in part virgin and in part with a refilling terrain without compaction with a width of 50 m and with a difference of levels between the most extreme points of 10 m.

Mechanical characterization of multicrystalline silicon wafers

The possibility of using more economical silicon feedstock, i.e. as support for epitaxial solar cells, is of interest when the cost reduction and the properties are attractive. We have investigated the mechanical behavior of two blocks of upgraded metallurgical silicon, which is known to present high content of impurities even after being purified by the directional solidification process. The impurities are mainly metals like Al and silicon compounds. Thus, it is important to characterize their effect in order to improve cell performance and to ensure the survival of the wafers throughout the solar value chain. Microstructure and mechanical properties were studied by means of ring on ring and three point bending tests. Additionally, Young���s modulus, hardness and fracture toughness were measured. These results showed that it is possible to obtain marked improvements in toughness when impurities act as microscopic internal crack arrestors. However, the same impurities can be initiators of damage due to residual thermal stresses introduced during the crystallization process.

On the economics of energy consumption in 4G networks: the case of Spain

Reducing energy consumption is one of the main challenges in most countries. For example, European Member States agreed to reduce greenhouse gas (GHG) emissions by 20% in 2020 compared to 1990 levels (EC 2008). Considering each sector separately, ICTs account nowadays for 2% of total carbon emissions. This percentage will increase as the demand of communication services and applications steps up. At the same time, the expected evolution of ICT-based developments - smart buildings, smart grids and smart transportation systems among others - could result in the creation of energy-saving opportunities leading to global emission reductions (Labouze et al. 2008), although the amount of these savings is under debate (Falch 2010). The main development required in telecommunication networks ?one of the three major blocks of energy consumption in ICTs together with data centers and consumer equipment (Sutherland 2009) ? is the evolution of existing infrastructures into ultra-broadband networks, the so-called Next Generation Networks (NGN). Fourth generation (4G) mobile communications are the technology of choice to complete -or supplement- the ubiquitous deployment of NGN. The risk and opportunities involved in NGN roll-out are currently in the forefront of the economic and policy debate. However, the issue of which is the role of energy consumption in 4G networks seems absent, despite the fact that the economic impact of energy consumption arises as a key element in the cost analysis of this type of networks. Precisely, the aim of this research is to provide deeper insight on the energy consumption involved in the usage of a 4G network, its relationship with network main design features, and the general economic impact this would have in the capital and operational expenditures related with network deployment and usage.

The PSE-3D instability analysis methodology for flows depending strongly on two and weakly on the third spatial dimension

The present contribution discusses the development of a PSE-3D instability analysis algorithm, in which a matrix forming and storing approach is followed. Alternatively to the typically used in stability calculations spectral methods, new stable high-order ���nitedi���erence-based numerical schemes for spatial discretization 1 are employed. Attention is paid to the issue of e���ciency, which is critical for the success of the overall algorithm. To this end, use is made of a parallelizable sparse matrix linear algebra package which takes advantage of the sparsity o���ered by the ���nite-di���erence scheme and, as expected, is shown to perform substantially more e���ciently than when spectral collocation methods are used. The building blocks of the algorithm have been implemented and extensively validated, focusing on classic PSE analysis of instability on the ���ow-plate boundary layer, temporal and spatial BiGlobal EVP solutions (the latter necessary for the initialization of the PSE-3D), as well as standard PSE in a cylindrical coordinates using the nonparallel Batchelor vortex basic ���ow model, such that comparisons between PSE and PSE-3D be possible; excellent agreement is shown in all aforementioned comparisons. Finally, the linear PSE-3D instability analysis is applied to a fully three-dimensional ���ow composed of a counter-rotating pair of nonparallel Batchelor vortices.

Simulating digital dividend auctions: Service neutrality versus dedicated licences

The award of the digital dividend can consolidate auctions as the preferred mechanism for spectrum allocation. Knowing in advance an estimate of what the results of an auction with these characteristics could be would be unquestionably useful for those in charge of designing the process, even if at the end another method such as a beauty contest is chosen. This article provides a simulation of a digital dividend auction in a major-type European country. In one of the scenarios, the spectrum is not pre-allocated to any service in particular (service neutrality) while in the remaining four, blocks of spectrum are pre-allocated to DTT, mobile multimedia and mobile broadband communications. The results of the simulations reveal that the service neutrality scenario maximizes revenues for the seller and that, in general, DTT operators would seem to have fewer opportunities as the spectrum packaging is less protective for them.

Homogeneous links and the Seifert matrix

Homogeneous links were introduced by Peter Cromwell, who pr oved that the projection surface of these links, that given by the Seifert al- gorithm, has minimal genus. Here we provide a different proof , with a geometric rather than combinatorial flavor. To do this, we fir st show a direct relation between the Seifert matrix and the decompo sition into blocks of the Seifert graph. Precisely, we prove that the Sei fert matrix can be arranged in a block triangular form, with small boxes in th e diagonal corresponding to the blocks of the Seifert graph. Then we pro ve that the boxes in the diagonal has non-zero determinant, by looking a t an explicit matrix of degrees given by the planar structure of the Seifer t graph. The paper contains also a complete classification of the homogen eous knots of genus one.

Impacto de los medios sociales en la estrategia de las organizaciones

Dado el impacto que las redes sociales tienen en la vida diaria de los pa��ses desarrollados o en v��as de desarrollo, ��stas han pasado a tener un papel clave en dicho desarrollo social. Dicha consideraci��n no s��lo debe centrarse en c��mo las personas forman las redes, sino las herramientas que emplean y la forma en la que estas deben ser tratadas por las organizaciones para conseguir una posici��n preferencial con los usuarios que forman las redes (considerando el creciente n��mero de ��stos todos los d��as). El presente trabajo trata de exponer la diferencia entre medios sociales y redes sociales, estableciendo una diferencia clara entre entre ambos, define lo que son los medios sociales (Social Media en Ingl��s), qu�� se debe considerar para que el uso de los mismos tenga una car��cter exitoso en sus operaciones y c��mo las organizaciones perciben la diferencia competitiva que ��stos aportan en sus actividades. Una vez definida, destacamos la importancia de la consideraci��n de estos nuevos medios en las estrategias de la compa����as. Para ello, debemos ver el ecosistema de los medios sociales de forma general, y focalizarnos en la relaci��n marca-compa����a con el usuario/cliente. La inclusi��n de los medios sociales en las estrategias de las compa����as, primero de forma independiente y, posteriormente, de forma integrada, hace que los modelos de negocio de las compa����as se vayan adaptando a los tiempos. Se describe el cambio de paradigma de los modelos de negocio afectados por la introducci��n de los medios sociales, los elementos y tipos de modelos de negocio que se pueden tener, as�� como la adaptaci��n de los modelos establecidos a los nuevos modelos. Posteriormente se ve c��mo las compa����as incluyen los medios sociales en su estrategia, a trav��s de una planificaci��n de medios sociales,partiendo de qu�� es una estrategia y c��mo debe evaluarse. Una vez se ha definido el contexto (qu�� son los medios sociales, redes sociales, modelo de negocio, estrategia; as�� como sus caracter��sticas), se definen los bloques funcionales de los medios sociales, con su paralelismo en t��rminos de la estrategia de las compa����as, as�� como se indican determinados factores de ��xito para su adopci��n. Hasta ahora, estamos mirando la organizaci��n de forma individual pero, dentro del mercado en el que desarrollan sus actividades, ��stas deben ser evaluadas sobre el grado de desarrollo de los medios sociales en sus operaciones; y poder establecer as�� comparativas, con otras organizaciones, en relaci��n a su grado de implantaci��n. Con dicho objetivo, desarrollaremos un modelo de madurez de medios sociales (Social Media Maturity Model, SMMM o SM3), de forma te��rica. ��C��mo considerar dicho modelo de forma realista?. Bas��ndonos en el m��todo del estudio de casos, se realizar�� una an��lisis e investigaci��n de diferentes organizaciones que nos indicar�� el grado de aproximaci��n del modelo de madurez referenciado, con respecto a la realidad. ABSTRACT Considering the impact that social networks have in the daily life in developed or developing countries, they have come to play a key role in this social development. This consideration should not only focus on how people set up networks, but the tools they use and how these ones should be addressed by organizations to achieve a preferential position with users, forming networks (considering the increasing number of them every day). This work tries to explain the difference between social media and social networking, establishing a clear difference between them, defines what is Social Media, which should be considered for its use has a successful character in their operations and how organizations perceive the competitive edge they bring in their activities. Once they are defined, we remark the importance of considering these new media in companies strategies. For this, we see the social media ecosystem in general, and to focus on brandcompany relationship with the user/client. The inclusion of social media strategies in the companies, independently and in a integrated way, makes the business models of companies evolve along the time. It is described the paradigm shift in business models affected by the introduction of social media, elements and types of business models that can be had, and the adaptation of established models to new models. After that, it���s shown how companies include social media strategy through social media planning and building on what is a strategy and how it should be evaluated. Once the context is defined (what is social media, social networking, business model, strategy, and its features), the functional blocks of social media are defined, with its parallelism in terms of the strategy of companies and specific success factors are indicated. So far, we are looking at the organization individually but within the market in which they operate, they must be evaluated on the degree of development of social media in their operations; and to establish and compare with other organizations in relation to their degree of implementation. With this goal, we will develop a maturity model for social media (Social Media Maturity Model, SMMM or SM3), theoretically. How to consider the model realistically?. Based on the case study method, the analysis and research of different organizations that it will indicate the accuracy of the maturity model referenced with respect to the actually performed.

El nuevo reto de relaci��n con los clientes: Social CRM

La evoluci��n de Internet al modelo Web 2.0, ha creado el nuevo sistema denominado Social Media, donde han proliferado un n��mero ingente de redes sociales, que han cambiado las formas de relaci��n y colaboraci��n entre los usuarios, as�� como la relaciones de ��stos y las empresas. En respuesta a estos dram��ticos cambios sociales y tecnol��gicos, que actualmente est��n dando forma a las relaciones negocio-empresa, las empresas est��n descubriendo que es necesario modificar la estrategia de utilizaci��n del CRM (Customer Relationship Management) con sus clientes y desarrollar nuevas capacidades que permitan la creaci��n de valor con los clientes. Y es aqu�� donde aparece el concepto de Social CRM, entendido como una estrategia centrada en entender, anticiparse y responder mejor a las necesidades de los clientes existentes o potenciales, aprovechando los datos sociales, para crear unas fuertes relaciones beneficiosas para ambas partes. En este trabajo se describe un modelo de adopci��n de Social CRM, aplicando un m��todo de an��lisis ���Top-Down���, y basado en el modelo de Gartner denominado ���The Eight Building Blocks of CRM��� [1]. El presente trabajo descompone el modelo de adopci��n descrito por Gartner, en los siguientes puntos. - Una decisi��n estrat��gica de la compa����a - Asomarse a la realidad social - Analizar las redes sociales. - Metodolog��a de adopci��n. - Despliegue y extensi��n en todos los departamentos de la compa����a y la adaptaci��n de los recursos humanos. - Selecci��n e integraci��n con las plataformas tradicionales de CRM - An��lisis de herramientas de monitorizaci��n de Social CRM El modelo propuesto tiene dos objetivos, por un lado pretende proporcionar la visi��n de c��mo CRM puede influir en los resultados empresariales en la era del cliente social, y por otro, proporcionar a los administradores c��mo las inversiones y los recursos existentes de CRM puede ser integrados con las nuevas tecnolog��as y procesos para formar capacidades que pueden mejorar el rendimiento del negocio. ABSTRACT. ���The Internet evolution to Web 2.0 model has created a new system called Social Media, where have proliferated a huge number of social networks which have changed the relationship and collaboration forms user-to-user and user-to-company. In response to these dramatic social and technological changes that are currently shaping the business-business relationships, companies are finding it necessary to modify the strategy for use of CRM (Customer Relationship Management) with customers and develop new capabilities to creating value with customers. And here is where the concept of Social CRM appears, understood as a focus on understanding, anticipating and responding to the needs of existing and potential customers strategy, leveraging social data to create a strong mutually beneficial relationships. In this paper describes an adoption model of Social CRM, using a "Top-Down" analysis method and based on the model of Gartner called "The Eight Building Blocks of CRM" [1]. This paper decomposes the adoption model described by Gartner in the following points. - A company strategic decision. - Look at social reality. - Analyze social networks. - Methodology adoption. - Deployment and extension in all departments of the company and the adaptation of human resources. - Selection and integration with traditional CRM platforms. - Analysis of monitoring tools for Social CRM. The proposed model has two objectives, firstly aims to provide insight into how CRM can influence business outcomes in the era of the social customer, and secondly, to provide administrators how investments and existing resources can be integrated CRM with new technologies and processes for developing capabilities that can increase business performance���.

Contribution to active multi-beam reconfigurable antennas for L and S bands

La presente tesis doctoral con t��tulo "Contribution to Active Multi-Beam Reconfigurable Antennas for L and S Bands" ha sido desarrollada por el investigador ingeniero de telecomunicaci��n estudiante de doctorado Javier Garc��a-Gasco Trujillo en el Grupo de Radiaci��n del Departamento de Se��ales, Sistemas y Radiocomunicaciones de la ETSI de Telecomunicaci��n de la Universidad Polit��cnica de Madrid bajo la direcci��n de los doctores Manuel Sierra P��rez y Jos�� Manuel Fern��ndez Gonz��lez. Durante d��cadas, el desarrollo de antenas de apuntamiento electr��nico ha estado limitado al ��rea militar. Su alto coste y su gran complejidad eran los mayores obst��culos que frenaban la introducci��n de esta tecnolog��a en aplicaciones comerciales de gran escala. La reciente aparici��n de componentes de estado s��lido pr��cticos, fiables, y de bajo coste ha roto la barrera del coste y ha reducido la complejidad, haciendo que las antenas reconfigurables de apuntamiento electr��nico sean una opci��n viable en un futuro cercano. De esta manera, las antenas phased array podr��an llegar a ser la joya de la corona que permitan alcanzar los futuros retos presentes en los sistemas de comunicaciones tanto civiles como militares. As�� pues, ahora es el momento de investigar en el desarrollo de antenas de apuntamiento electr��nico de bajo coste, donde los nuevos componentes de estado s��lido comerciales forman el n��cleo duro de la arquitectura. De esta forma, el estudio e implementaci��n de estos arrays de antenas activas de apuntamiento electr��nico capaces de controlar la fase y amplitud de las distintas se��ales implicadas es uno de los grandes retos de nuestro tiempo. Esta tesis se enfrenta a este desaf��o, proponiendo novedosas redes de apuntamiento electr��nico e innovadores m��dulos de transmisi��n/recepci��n (T/R) utilizando componentes de estado s��lido de bajo coste, que podr��n integrar asequibles antenas activas reconfigurables multihaz en bandas L y S. En la primera parte de la tesis se realiza una descripci��n del estado del arte de las antenas phased array, incluyendo su base te��rica y sus ventajas competitivas. Debido a que las contribuciones obtenidas en la presente tesis han sido realizadas dentro de distintos proyectos de investigaci��n, donde se han manejada antenas de simple/doble polarizaci��n circular y simple/doble banda de trabajo, se describen detenidamente los dos proyectos m��s relevantes de la investigaci��n: el radar de basura espacial de la Agencia Espacial Europea (ESA), Space Situational Awareness (SSA); y la estaci��n base de seguimiento y control de sat��lites de ��rbita baja, GEOdesic Dome Array (GEODA). Sin lugar a dudas, los dispositivos desfasadores son uno de los componentes clave en el dise��o de antenas phased arrays. Recientemente se ha observado una gran variaci��n en el precio final de estos dispositivos, llegando en ocasiones a l��mites inasequibles. As�� pues, se han propuesto distintas t��cnicas de conformaci��n de haz alternativas a la utilizaci��n de componentes desfasadores comerciales: el desfasador de l��neas conmutadas, la red de haz conmutado, y una novedosa red desfasadora divisora/combinadora de potencia. Para mostrar un uso pr��ctico de las mismas, se ha propuesto el uso de las tres alternativas para el caso pr��ctico del subarray de cinco elementos de la celda GEODA-SARAS. Tras dicho estudio se obtiene que la novedosa red desfasadora divisora/combinadora de potencia propuesta es la que mejor relaci��n comportamiento/coste presenta. Para verificar su correcto funcionamiento se construye y mide los dos bloques principales de los que est�� compuesta la red total, comprobando que en efecto la red responde seg��n lo esperado. La estructura m��s simple que permite realizar un barrido plano es el array triangular de tres elementos. Se ha realizado el dise��o de una nueva red multihaz que es capaz de proporcionar tres haces ortogonales en un ��ngulo de elevaci��n _0 y un haz adicional en la direcci��n broadside utilizando el mencionado array triangular de tres elementos como antena. En primer lugar se realizar una breve introducci��n al estado del arte de las redes cl��sicas multihaz. As�� mismo se comentan innovadores dise��os de redes multihaz sin p��rdidas. El estudio da paso a las redes disipativas, de tal forma que se analiza su base matem��tica y se muestran distintas aplicaciones en arrays triangulares de tres elementos. Finalmente, la novedosa red b��sica propuesta se presenta, mostrando simulaciones y medidas de la misma para el caso pr��cticoo de GEODA. Tambi��n se ha dise��ado, construido y medido una red compuesta por dos redes b��sicas complementarias capaz de proporcionar seis haces cuasi-ortogonales en una direcci��n _0 con dos haces superpuestos en broadside. La red propuesta queda totalmente validada con la fabricaci��n y medida de estos con prototipos. Las cadenas de RF de los m��dulos T/R de la nueva antena GEODA-SARAS no son algo trivial. Con el fin de mostrar el desarrollo de una cadena compleja con una gran densidad de componentes de estado s��lido, se presenta una descripci��n detallada de los distintos componentes que integran las cadenas de RF tanto en transmisi��n como en recepci��n de la nueva antena GEODA-SARAS. Tras presentar las especificaciones de la antena GEODA-SARA y su diagrama de bloques esquem��tico se describen los dos bloques principales de las cadenas de RF: la celda de cinco elementos, y el m��dulo de conversi��n de panel. De la misma manera tambi��n se presentar�� el m��dulo de calibraci��n integrado dentro de los dos bloques principales. Para comprobar que el funcionamiento esperado de la placa es el adecuado, se realizar�� un an��lisis que tratar�� entre otros datos: la potencia m��xima en la entrada del transmisor (comprobando la saturaci��n de la cadena), se��al de recepci��n m��nima y m��xima (verificando el rango de sensibilidad requerido), y el factor G/T (cumpliendo la especificaci��n necesaria). As�� mismo se mostrar�� un breve estudio del efecto de la cuantificaci��n de la fase en el conformado de haz de RF. Los estudios muestran que la composici��n de las cadenas de RF permite el cumplimiento de las especificaciones necesarias. Finalmente la tesis muestra las conclusiones globales del trabajo realizado y las l��neas futuras a seguir para continuar con esta l��nea de investigaci��n. ABSTRACT This PhD thesis named "Contribution to Active Multi-Beam Reconfigurable Antennas for L and S Bands", has been written by the Electrical Engineer MSc. researcher Javier Garc��a-Gasco Trujillo in the Grupo de Radiaci��n of the Departamento de Se��ales, Sistemas y Radiocomunicaciones from the ETSI de Telecomunicaci��n of the Universidad Polit��cnica de Madrid. For decades, the implementation of electronically steerable phased array antennas was confined to the military area. Their high cost and complexity were the major obstacles to introduce this technology in large scale commercial applications. The recent emergence of new practical, low-cost, and highly reliable solid state devices; breaks the barrier of cost and reduces the complexity, making active phased arrays a viable future option. Thus, phased array antennas could be the crown jewel that allow to meet the future challenges in military and civilian communication systems. Now is time to deploy low-cost phased array antennas, where newly commercial components form the core of the architecture. Therefore, the study and implementation of these novel low-cost and highly efficient solid state phased array blocks capable of controlling signal phase/amplitude accurately is one of the great challenges of our time. This thesis faces this challenge, proposing innovative electronic beam steering networks and transmitter/ receiver (T/R) modules using affordable solid state components, which could integrate fair reconfigurable phased array antennas working in L and S bands. In the first part of the thesis, a description of the state of art of phased array antennas, including their fundamentals and their competitive advantages, is presented. Since thesis contributions have been carried out for different research projects, where antennas with single/double circular polarization and single/double working frequency bands have been examined, frameworks of the two more important projects are detailed: the Space Situational Awareness (SSA) programme from the European Space Agency (ESA), and the GEOdesic Dome Array (GEODA) project from ISDEFE-INSA and the ESA. Undoubtedly, phase shifter devices are one of the key components of phased array antennas. Recent years have witnessed wide fluctuations in commercial phase shifter prices, which sometimes led to unaffordable limit. Several RF steering technique alternatives to the commercial phase shifters are proposed, summarized, and compared: the switched line phase shifter, the switched-beam network, and the novel phase shifter power splitter/combiner network. In order to show a practical use of the three different techniques, the five element GEODA-SARAS subarray is proposed as a real case of study. Finally, a practical study of a newly phase shifter power splitter/combiner network for a subarray of five radiating elements with triangular distribution is shown. Measurements of the two different phase shifter power splitter/combiner prototypes integrating the whole network are also depicted, demonstrating their proper performance. A triangular cell of three radiating elements is the simplest way to obtain a planar scanner. A new multibeam network configuration that provides three orthogonal beams in a desired _0 elevation angle and an extra one in the broadside steering direction for a triangular array of three radiating elements is introduced. Firstly, a short introduction to the state of art of classical multi-beam networks is presented. Lossless network analysis, including original lossless network designs, are also commented. General dissipative network theory as well as applications for array antennas of three radiating elements are depicted. The proposed final basic multi-beam network are simulated, built and measured to the GEODA cell practical case. A combined network that provides six orthogonal beams in a desired _0 elevation angle and a double seventh one in the broadside direction by using two complementary proposed basic networks will be shown. Measurements of the whole system will be also depicted, verifying the expected behavior. GEODA-SARAS T/R module RF chains are not a trivial design. A thorough description of all the components compounding GEODA-SARAS T/R module RF chains is presented. After presenting the general specifications of the GEODA-SARAS antenna and its block diagrams; two main blocks of the RF chains, the five element cell and the panel conversion module, are depicted and analyzed. Calibration module integrated within the two main blocks are also depicted. Signal flow throw the system analyzing critical situations such as maximum transmitted power (testing the chain unsaturation), minimum and maximum receiving signal (verifying sensitivity range), maximum receiver interference signals (assuring a proper reception), and G/T factor (fulfilling the technical specification) are evaluated. Phase quantization error effects are also listed. Finally, the manuscript contains the conclusions drawn of the present research and the future work.

Dise��o electr��nico de la tarjeta de interfaz y control para un equipo de seguimiento en elevaci��n en un subsistema de contramedidas electr��nicas

Como apoyo al Subsistema ECM tradicional de los sistemas de Guerra Electr��nica, surge el Equipo de Seguimiento en Elevaci��n cuyo fin es la b��squeda de la amenaza en elevaci��n. Ante la necesidad de un mayor n��mero de l��neas entre los bloques internos de este Equipo de Seguimiento, se hace necesario el dise��o de una Tarjeta de Interfaz y Control. La tarjeta se ocupar�� de realizar el control de datos y flujo de se��ales de m��dulos RF que componen el Equipo, haciendo de interfaz entre las Tarjetas Procesadoras y Digitalizadoras, as�� como entre la Tarjeta de Proceso y el Bloque de Recepci��n. Una vez que se haya realizado el an��lisis de la necesidad de controlar estas se��ales, estudiado las especificaciones y los requisitos funcionales del Sistema, se proceder�� a implementar el dise��o hardware y desarrollo firmware de la Tarjeta de Interfaz y Control de un Equipo de Seguimiento en Elevaci��n para un Subsistema ECM, que constituye el objetivo de este PFC. ABSTRACT. In order to find a threat on elevation, and as a support on the basic ECM subsystems of E-war systems, the Elevation Tracking Equipment appears. To the need of a bigger number of lines between inside blocks of this Tracking Equipment, the design of an Interface and Control Board is needed. This board will deal with the data control and with the flow of RF modules signals that set up the Equipment, and will also work as an interface between the Processing and Digitalizing Board, as well as between the Process Board and the Reception Block. Once the signal control necessity analysis has been made, and once the specifications and functional System requirements have been studied, the hardware design and the firmware development will be ran as a target of PFC.

Estudio de los materiales que componen el sistema constructivo de las viviendas del casco hist��rico de Maracaibo (Venezuela)

En este trabajo de investigaci��n que se presenta para optar al grado de Doctor, se analizan y estudian los materiales que conforman las viviendas de mamposter��a de arenisca ���Piedra de Ojo��� del casco hist��rico de Maracaibo, Venezuela, construidas en el siglo XIX. No existe una bibliograf��a descriptiva t��cnico-constructiva del sistema constructivo, por lo que esta tesis complementa la escasa descripci��n estil��stica existente donde apenas se mencionan algunos materiales de construcci��n. Definido el marco hist��rico y las manzanas del ��rea en donde se encontraban las viviendas preseleccionadas a estudiar, en la visita de campo se seleccionaron 12 que se encontraban en estado de deterioro, y que permitieron recolectar las muestras m��s f��cilmente. Para realizar la caracterizaci��n y comportamientos de los diferentes materiales utilizados: piedra y morteros en los cerramientos, maderas en armaduras de tejados, techos y carpinter��a de puertas y ventanas, cer��micos en muros y acabados, etc. Para complementar lo antes dicho se ha dividido esta tesis en seis cap��tulos: En el cap��tulo I se desarrolla el estado del arte a nivel nacional e internacional de trabajos de investigaci��n, similares. Se aborda la memoria hist��rica, que es una rese��a de la evoluci��n de la vivienda en la ciudad de Maracaibo. En el cap��tulo II se describe la metodolog��a empleada en la tesis, de acuerdo a los objetivos, tanto generales como espec��ficos de la investigaci��n. Que ha cubierto diferentes frentes: consulta bibliogr��fica, levantamiento planim��trico, toma de muestras, an��lisis de visu, caracterizaci��n f��sico-qu��mica y correlaci��n de resultados. Se ha desarrollado el trabajo tanto in situ como en laboratorio y despacho. El cap��tulo III presenta la caracterizaci��n de la arenisca ���Piedra de Ojo���, se desarrolla: la descripci��n geol��gica y caracterizaci��n petrol��gica. Se rese��an los ensayos realizados en laboratorio como: caracterizaci��n de visu, caracterizaci��n petrogr��fica, estudio petrogr��fico por microcopia ��ptica de trasmisi��n, estudio petrogr��fico por microcopia electr��nica de barrido, microscopia electr��nica de barrido en modo electrones secundarios (SSE) y microscopia electr��nica de barrido en modo electrones retrodispersados. Tambi��n las propiedades escalares de los mampuestos y los siguientes valores: densidades, porosidades y resistencia mec��nicas, entre otros. En el cap��tulo IV se analizan las caracter��sticas de los morteros aplicados en las viviendas, y la patolog��a o lesiones que presentan. Se clasifican en tres tipos: mortero de junta o asiento, de enfoscado y revoco. Se documenta la realizaci��n de los ensayos f��sicos y qu��micos, resistencia mec��nica y de granulometr��a; se explican sus componentes principales: conglomerante de cal, ��ridos y aditivos y la tecnolog��a de fabricaci��n, as�� como las caracter��sticas f��sicas, h��dricas, qu��micas y granulom��tricas. El cap��tulo V, contiene las aplicaciones constructivas de los materiales de alba��iler��a, Se describen otros elementos de la vivienda como; cimentaciones, muros mixtos, molduras, apliques y pinturas y finalmente pavimentos. Y en el cap��tulo VI se analizan las especies de madera m��s representativas usadas en las armaduras de las cubiertas, as�� como los elementos de cubrici��n. De igual forma se describe la carpinter��a de puertas y ventanas, as�� como sus dinteles o cargaderos de madera y se realiza la identificaci��n anat��mica, las propiedades f��sicas y mec��nicas de las utilizadas. Entre los resultados y conclusiones se determin�� que el 90% de los materiales utilizados en su construcci��n proceden de zonas cercanas a la construcci��n de la vivienda, como la formaci��n El Milagro convertida en cantera de piedra y que el resto de los materiales proven��an de la Isla de Toas y de la exportaci��n de las islas del Caribe y de Europa como el cemento. El principal aporte de esta investigaci��n es el an��lisis t��cnico constructivo y la caracterizaci��n f��sica, mec��nica y qu��mica de los materiales de la vivienda, con el fin de que dicha informaci��n sea usada para definir los materiales nuevos a utilizar en las restauraciones de las viviendas y en futuras l��neas de investigaci��n. ABSTRACT In this research paper submitted to opt to the degree of Doctor, the materials that make the ���Piedra de Ojo��� sandstone masonry houses of the historical center of Maracaibo, Venezuela, built in the XIX century, are analyzed and studied. There exists no technical-constructive descriptive literature of the constructive system, so this thesis complements the very limited existing stylistic description, where barely some construction materials are mentioned. With the historical context and the blocks of the area where the preselected houses to be studied being defined, 12 of these houses that were in a state of decay (deterioration) were selected and this condition allowed to collect samples more easily, in order to carry out the characterization and behavior of the different materials used: stone and mortars in the walls, wood trusses in roofs, ceilings and woodwork of doors and windows, walls and ceramic finishes, etc. To complement the foregoing, this thesis has been divided in six chapters: In Chapter I, the state of art at national and international levels of similar research is developed, which is a review of the evolution of housing in the city of Maracaibo. In Chapter II, the methodology used in the thesis is described, according to the research���s objectives, general and specific ones, which have covered several fronts: literature survey, planimetric survey, sampling, visu analysis, physical-chemical characterization and correlation of results. Chapter III presents the characterization of the ���Piedra de Ojo��� sandstone; geological description and petrologic characterization are developed. Essays performed in the laboratory are reviewed, such as: visu characterization, petrographic characaterization, petrographic study by optical microscopy of transmission, petrographic study by electronic scanning microscopy in secondary electron mode (SSE) and electron microscopy scaning by backscattered electron mode. Also scalar properties of the masonry and the following: density, porosity and mechanical resistance, among others. In Chapter IV, characteristics of the mortars used in the houses are analyzed and pathology or damages are presented. They are classified into three types: grout, cement render and plaster. Physical and chemical testing, mechanical strength and grain size (granulometric) is documented; its main components are explained: lime binder, aggregates and additives and manufacturing technology as well as the physical, water, chemical and granulometric characteristics. Chapter V contains the constructive applications of masonry materials. Other housing elements are described, such as; foundations, mixed walls, moldings, wall paintings and finally floorings (pavements). And in chapter VI the most representative species of wood used in the overhead fixtures and cover elements are analyzed. Likewise, woodwork of doors and windows and their wooden lintels or landings are described; anatomical identification and physical and mechanical properties of the ones used is made. The results and conclusions determined that 90% of the materials used in its construction came from areas near the construction of housing, such as El Milagro formation, converted into stone quarry and other materials came from the Toas Island and from the export of the Caribbean islands and Europe, such as cement. The main contribution of this research is the constructive technical analysis and physical, mechanical and chemical characterization of the materials of the houses, in order that such information is used to define the new materials to be used in the housing restoration and future research lines.

Detectores monol��ticos y sensores compatibles con altos campos magn��ticos para tomograf��a por emisi��n de positrones

Esta tesis recoje un trabajo experimental centrado en profundizar sobre el conocimiento de los bloques detectores monol��ticos como alternativa a los detectores segmentados para tomograf��a por emisi��n de positrones (Positron Emission Tomography, PET). El trabajo llevado a cabo incluye el desarrollo, la caracterizaci��n, la puesta a punto y la evaluaci��n de prototipos demostradores PET utilizando bloques monol��ticos de ortosilicato de lutecio ytrio dopado con cerio (Cerium-Doped Lutetium Yttrium Orthosilicate, LYSO:Ce) usando sensores compatibles con altos campos magn��ticos, tanto fotodiodos de avalancha (Avalanche Photodiodes, APDs) como fotomultiplicadores de silicio (Silicon Photomultipliers, SiPMs). Los prototipos implementados con APDs se construyeron para estudiar la viabilidad de un prototipo PET de alta sensibilidad previamente simulado, denominado BrainPET. En esta memoria se describe y caracteriza la electr��nica frontal integrada utilizada en estos prototipos junto con la electr��nica de lectura desarrollada espec��ficamente para los mismos. Se muestran los montajes experimentales para la obtenci��n de las im��genes tomogr��ficas PET y para el entrenamiento de los algoritmos de red neuronal utilizados para la estimaci��n de las posiciones de incidencia de los fotones �� sobre la superficie de los bloques monol��ticos. Con el prototipo BrainPET se obtuvieron resultados satisfactorios de resoluci��n energ��tica (13 % FWHM), precisi��n espacial de los bloques monol��ticos (~ 2 mm FWHM) y resoluci��n espacial de la imagen PET de 1,5 - 1,7 mm FWHM. Adem��s se demostr�� una capacidad resolutiva en la imagen PET de ~ 2 mm al adquirir simult��neamente im��genes de fuentes radiactivas separadas a distancias conocidas. Sin embargo, con este prototipo se detectaron tambi��n dos limitaciones importantes. En primer lugar, se constat�� una falta de flexibilidad a la hora de trabajar con un circuito integrado de aplicaci��n espec��fica (Application Specific Integrated Circuit, ASIC) cuyo dise��o electr��nico no era propio sino comercial, unido al elevado coste que requieren las modificaciones del dise��o de un ASIC con tales caracter��sticas. Por otra parte, la caracterizaci��n final de la electr��nica integrada del BrainPET mostr�� una resoluci��n temporal con amplio margen de mejora (~ 13 ns FWHM). Tomando en cuenta estas limitaciones obtenidas con los prototipos BrainPET, junto con la evoluci��n tecnol��gica hacia matrices de SiPM, el conocimiento adquirido con los bloques monol��ticos se traslad�� a la nueva tecnolog��a de sensores disponible, los SiPMs. A su vez se inici�� una nueva estrategia para la electr��nica frontal, con el ASIC FlexToT, un ASIC de dise��o propio basado en un esquema de medida del tiempo sobre umbral (Time over Threshold, ToT), en donde la duraci��n del pulso de salida es proporcional a la energ��a depositada. Una de las caracter��sticas m��s interesantes de este esquema es la posibilidad de manejar directamente se��ales de pulsos digitales, en lugar de procesar la amplitud de las se��ales anal��gicas. Con esta arquitectura electr��nica se sustituyen los conversores anal��gicos digitales (Analog to Digital Converter, ADCs) por conversores de tiempo digitales (Time to Digital Converter, TDCs), pudiendo implementar ��stos de forma sencilla en matrices de puertas programmable ���in situ��� (Field Programmable Gate Array, FPGA), reduciendo con ello el consumo y la complejidad del dise��o. Se construy�� un nuevo prototipo demostrador FlexToT para validar dicho ASIC para bloques monol��ticos o segmentados. Se ha llevado a cabo el dise��o y caracterizaci��n de la electr��nica frontal necesaria para la lectura del ASIC FlexToT, evaluando su linealidad y rango din��mico, el comportamiento frente a ruido as�� como la no linealidad diferencial obtenida con los TDCs implementados en la FPGA. Adem��s, la electr��nica presentada en este trabajo es capaz de trabajar con altas tasas de actividad y de discriminar diferentes centelleadores para aplicaciones phoswich. El ASIC FlexToT proporciona una excelente resoluci��n temporal en coincidencia para los eventos correspondientes con el fotopico de 511 keV (128 ps FWHM), solventando las limitaciones de resoluci��n temporal del prototipo BrainPET. Por otra parte, la resoluci��n energ��tica con bloques monol��ticos leidos por ASICs FlexToT proporciona una resoluci��n energ��tica de 15,4 % FWHM a 511 keV. Finalmente, se obtuvieron buenos resultados en la calidad de la imagen PET y en la capacidad resolutiva del demostrador FlexToT, proporcionando resoluciones espaciales en el centro del FoV en torno a 1,4 mm FWHM. ABSTRACT This thesis is focused on the development of experimental activities used to deepen the knowledge of monolithic detector blocks as an alternative to segmented detectors for Positron Emission Tomography (PET). It includes the development, characterization, setting up, running and evaluation of PET demonstrator prototypes with monolithic detector blocks of Cerium-doped Lutetium Yttrium Orthosilicate (LYSO:Ce) using magnetically compatible sensors such as Avalanche Photodiodes (APDs) and Silicon Photomultipliers (SiPMs). The prototypes implemented with APDs were constructed to validate the viability of a high-sensitivity PET prototype that had previously been simulated, denominated BrainPET. This work describes and characterizes the integrated front-end electronics used in these prototypes, as well as the electronic readout system developed especially for them. It shows the experimental set-ups to obtain the tomographic PET images and to train neural networks algorithms used for position estimation of photons impinging on the surface of monolithic blocks. Using the BrainPET prototype, satisfactory energy resolution (13 % FWHM), spatial precision of monolithic blocks (~ 2 mm FWHM) and spatial resolution of the PET image (1.5 ��� 1.7 mm FWHM) in the center of the Field of View (FoV) were obtained. Moreover, we proved the imaging capabilities of this demonstrator with extended sources, considering the acquisition of two simultaneous sources of 1 mm diameter placed at known distances. However, some important limitations were also detected with the BrainPET prototype. In the first place, it was confirmed that there was a lack of flexibility working with an Application Specific Integrated Circuit (ASIC) whose electronic design was not own but commercial, along with the high cost required to modify an ASIC design with such features. Furthermore, the final characterization of the BrainPET ASIC showed a timing resolution with room for improvement (~ 13 ns FWHM). Taking into consideration the limitations obtained with the BrainPET prototype, along with the technological evolution in magnetically compatible devices, the knowledge acquired with the monolithic blocks were transferred to the new technology available, the SiPMs. Moreover, we opted for a new strategy in the front-end electronics, the FlexToT ASIC, an own design ASIC based on a Time over Threshold (ToT) scheme. One of the most interesting features underlying a ToT architecture is the encoding of the analog input signal amplitude information into the duration of the output signals, delivering directly digital pulses. The electronic architecture helps substitute the Analog to Digital Converters (ADCs) for Time to Digital Converters (TDCs), and they are easily implemented in Field Programmable Gate Arrays (FPGA), reducing the consumption and the complexity of the design. A new prototype demonstrator based on SiPMs was implemented to validate the FlexToT ASIC for monolithic or segmented blocks. The design and characterization of the necessary front-end electronic to read-out the signals from the ASIC was carried out by evaluating its linearity and dynamic range, its performance with an external noise signal, as well as the differential nonlinearity obtained with the TDCs implemented in the FPGA. Furthermore, the electronic presented in this work is capable of working at high count rates and discriminates different phoswich scintillators. The FlexToT ASIC provides an excellent coincidence time resolution for events that correspond to 511 keV photopeak (128 ps FWHM), resolving the limitations of the poor timing resolution of the BrainPET prototype. Furthermore, the energy resolution with monolithic blocks read by FlexToT ASICs provides an energy resolution of 15.4 % FWHM at 511 keV. Finally, good results were obtained in the quality of the PET image and the resolving power of the FlexToT demonstrator, providing spatial resolutions in the centre of the FoV at about 1.4 mm FWHM.

Implementaci��n de efectos de audio en la tarjeta Raspberry Pi B+

Este proyecto consiste en el dise��o e implementaci��n de un procesador digital de efectos de audio en tiempo real orientado a instrumentos el��ctricos tales como guitarras, bajos, teclados, etc. El procesador est�� basado en la tarjeta Raspberry Pi B+, ordenador de placa reducida de bajo coste, desarrollado en Reino unido y cuyo lanzamiento tuvo lugar en el a��o 2012. En primer lugar, ha sido necesario lograr que la tarjeta asuma la funcionalidad de un procesador de audio en tiempo real. Para ello se ha instalado un sistema operativo Linux orientado a Raspberry (Raspbian) y se ha hecho uso de Pure Data (Pd): lenguaje de programaci��n gr��fico que fue desarrollado en los a��os 90 por Miller Puckette con intenci��n de ser enfocado a la creaci��n de eventos multimedia y de m��sica por computador. El papel que desempe��a Pd es de capa intermedia entre el hardware y el software ya que se encarga de tomar bloques de N muestras del convertidor anal��gico/digital y encaminarlas a trav��s del flujo de se��al dise��ado gr��ficamente. En segundo lugar, se han implementado diferentes efectos de audio de distintas caracter��sticas. As�� pues, se encuentran efectos basados en retardos, filtros digitales y procesadores de din��mica. Concretamente, los efectos implementados son los siguientes: delay, flanger, vibrato, reverberador de Schroeder, filtros (paso bajo, paso alto y paso banda), ecualizador param��trico y compresor y expansor de din��mica. Estos efectos han sido implementados en lenguaje C de acuerdo con la API de Pd. Con esto se ha conseguido obtener un objeto por cada efecto, el cual es ���instanciado��� en Pd pudiendo ejecutarlo en tiempo real. En este proyecto se expone la problem��tica que supone cada paso del dise��o proponiendo soluciones v��lidas. Adem��s se incluye una gu��a paso a paso para configurar la tarjeta y lograr realizar un bypass de se��al y un efecto simple partiendo desde cero. ABSTRACT. This project involves the design and implementation of a digital real-time audio processor for electrical instruments (guitars, basses, keyboards, etc.). The processor is based on the Raspberry Pi B + card: low cost computer, developed in UK in 2012. First, it was necessary to make the cards assume the functionality of a real time audio processor. A Linux operating system called Raspberry (Raspbian) was installed. In this Project is used Pure Data (Pd): a graphical programming language developed in the 90s by Miller Puckette intending to be focused on creating multimedia and computer music events. The role of Pd is an intermediate layer between the hardware and the software. It is responsible for taking blocks of N samples of the analog/digital converter and route it through the signal flow. Secondly, it is necessary to implemented the different audio effects. There are delays based effects, digital filter and dynamics effects. Specifically, the implemented effects are: delay, flanger, vibrato, Schroeder reverb, filters (lowpass, highpass and bandpass), parametric equalizer and compressor and expander dynamics. These effects have been implemented in C language according to the Pd API. As a result, it has been obtained an object for each effect, which is instantiated in Pd. In this Project, the problems of every step are exposed with his corresponding solution. It is inlcuded a step-by-step guide to configure the card and achieve perform a bypass signal process and a simple effect.