Estudio de implantación de una industria de motores de baja tensión ubicada en Catalunya

El objeto de este proyecto es el diseño de una nave industrial fabricante de motores de baja tensión para la industria en general

Mecanismos de descubrimiento de gateways adaptativos para redes ad hoc conectadas a redes fijas

Los principales objetivos de este TFC son el análisis de un nuevo mecanismo de descubrimiento de gateways para las redes ad hoc conectadas a redes fijas y la propuesta de un nuevo mecanismo, variante del mecanismo anterior. Una vez analizados los dos mecanismos los compararemos con los mecanismos que se implementan en la actualidad y sacaremos conclusiones sobre que mecanismo es más eficiente para las aplicaciones en tiempo real que funcionan sobre redes ad hoc conectadas a redes fijas. Hemos fragmentado el proyecto en varios puntos, para entender el funcionamiento de este tipo de redes, sus protocolos, sus características, y finalmente llevar a cabo nuestros objetivos. Los puntos son los siguientes: • Estudio de las redes ad hoc • Estudio de los diferentes mecanismos de descubrimiento de gateways de redes ad hoc que existen en la actualidad. • Estudio de un nuevo protocolo de descubrimiento de gateways con provisión de QoS. • Propuesta y estudio de una nueva variante basada en protocolo anterior. • Simulación de los protocolos de descubrimiento de gateways híbrido, adaptativo y nuestra variante. • Comparación de los resultados de las simulaciones y conclusiones. • Realización de la patente de los protocolos propuestos.La gran evolución que han sufrido las comunicaciones en los últimos años y la necesidad surgida de estar conectado en cualquier momento y en cualquier lugar, ha permitido que las redes inalámbricas tomen un papel relevante en las comunicaciones actuales, permitiendo movilidad y conectividad permanentes. En este TFC nos centraremos en el estudio, análisis y simulación de las redes ad hoc conectadas a una red fija a través de gateways. Analizaremos los tres mecanismos de descubrimiento de gateways que se utilizan actualmente para las comunicaciones en las redes ad hoc. Presentaremos un nuevo protocolo de descubrimiento de gateways que mejora el rendimiento y la eficiencia de la red y añadiremos una nueva variante, derivada de este nuevo protocolo, ideada por nosotros. Con estas nuevas propuestas se consigue añadir QoS (Quality of service, calidad de servicio), inexistente en los protocolos actuales, priorizando el tráfico de las aplicaciones de tiempo real (VoIP) frente al resto de flujos de la red. Para obtener los datos necesarios sobre el comportamiento de estos nuevos protocolos, se ha optado por utilizar el programa de simulación de redes NS (Network Simulator). En estas simulaciones se ha comparado el comportamiento del protocolo de descubrimiento de gateways híbrido, con el protocolo propuesto y con nuestra variante. Analizando los resultados de las simulaciones vemos que el comportamiento del protocolo propuesto y de nuestra variante mejoran la eficiencia de la red ad hoc conectada a la red fija. Por último, se han seguido los pasos necesarios para presentar una solicitud de patente en la Oficina Española de Patentes y Marcas, del protocolo de descubrimiento de gateways presentado y nuestra variante

Double-stub loaded microstrip line reader for very high data density microwave encoders

Compact and high-data density microwave encoders useful for motion control and near-field chipless radio frequency identification (chipless-RFID) applications are proposed in this paper. The encoders are chains of metallic strips etched on a dielectric substrate. The reader consists of a microstrip line loaded with a pair of identical open-ended folded stubs located at different positions and oriented face-to-face by their extremes. By displacing the encoder over the extremes of the stubs, interstub coupling arises when a strip is located on top of the stubs, thereby generating two transmission zeros (rather than one) in the frequency response of the line. Thus, the presence of a strip on top of the face-to-face stubs produces a variation in the transmission coefficient of the line, which in turn can be detected by feeding the line with a harmonic signal, conveniently tuned. Encoder motion generates an amplitude modulated (AM) signal at the output port of the line with peaks, or dips, separated by a time distance dictated by the relative velocity between the reader and the encoder. Moreover, by making certain strips of the chain inoperative (e.g., by cutting them), it is possible to encode information that can be read as the absence (logic state "1") or presence (logic state "0") of peaks, or dips, at predefined positions in the output AM signal of the reader line. Since short strips suffice to generate interstub coupling, unprecedented data density per surface (DPS = 26.04 bit/cm 2 ) is obtained, as revealed by the implementation of 6.4 mm × 60 mm 100-bit encoder

Space-charge polarization in microstructured solid dielectrics

The electromechanical response of deformable solid dielectrics strongly depends on their polarizability, which is often the result of several concomitant micromechanisms of diverse origin. When a specimen possesses a fine microstructure and contains a certain amount of mobile ions, the intrinsic polarization of atomic and molecular origin can be significantly enhanced by an extrinsic polarization produced by space charges around microstructural interfaces blocking the flow of ions. This space-charge polarization is often found, for instance, in polycrystalline ceramics at low-frequency loadings, and has been recently proposed as a possible micromechanism responsible for the extreme dielectric enhancements observed in certain nanofilled polymers and perovskite-type ceramics. This work presents a continuum multiscale description for the electrostatic response of microstructured solid dielectrics undergoing intrinsic and space-charge polarization. To ease the presentation, attention is restricted to mechanically rigid solids containing a single species of mobile ions. The formulation can, however, be adapted to more complex systems. The relevant field equations of electrostatics are recast in the form of a minimum energy principle for the electrostatic and chemical potentials, and a two-scale version of the principle in terms of an effective energy density is then proposed. Elementary bounds and approximate estimates for the effective energy density are also provided. By way of example, the formulation is used to explore the dependence of the macroscopic response upon microstructural morphology in multiphase layered media, with focus on constitutive nonlinearity and microstructural size effects.Publicado en: Mecánica Computacional vol. XXXV, no.24Facultad de Ingenierí

3D-printed all-dielectric electromagnetic encoders with synchronous reading for measuring displacements and velocities

Altres ajuts: ICREAIn this paper, 3D-printed electromagnetic (or microwave) encoders with synchronous reading based on permittivity contrast, and devoted to the measurement of displacements and velocities, are reported for the first time. The considered encoders are based on two chains of linearly shaped apertures made on a 3D-printed high-permittivity dielectric material. One such aperture chain contains the identification (ID) code, whereas the other chain provides the clock signal. Synchronous reading is necessary in order to determine the absolute position if the velocity between the encoder and the sensitive part of the reader is not constant. Such absolute position can be determined as long as the whole encoder is encoded with the so-called de Bruijn sequence. For encoder reading, a splitter/combiner structure with each branch loaded with a series gap and a slot resonator (each one tuned to a different frequency) is considered. Such a structure is able to detect the presence of the apertures when the encoder is displaced, at short distance, over the slots. Thus, by injecting two harmonic signals, conveniently tuned, at the input port of the splitter/combiner structure, two amplitude modulated (AM) signals are generated by tag motion at the output port of the sensitive part of the reader. One of the AM envelope functions provides the absolute position, whereas the other one provides the clock signal and the velocity of the encoder. These synchronous 3D-printed all-dielectric encoders based on permittivity contrast are a good alternative to microwave encoders based on metallic inclusions in those applications where low cost as well as major robustness against mechanical wearing and aging effects are the main concerns

Influence of metallic inclusions on the electromechanical response of ferroelectric ceramics

Theoretical estimates are given for the overall dissipative response of ferroelectric ceramics with random dispersions of metallic inclusions under arbitrary loading histories. The fer- roelectric behavior of the matrix is described via a stored energy density and a dissipation potential in accordance with the theory of generalized standard materials. An implicit time- discretization scheme is used to generate a variational representation of the overall response in terms of a single incremental potential. Estimates are then generated by constructing se- quentially laminated microgeometries of particulate type whose overall incremental potential can be computed exactly. Because they are realizable, by construction, these estimates are guaranteed to conform with any material constraints, to satisfy all pertinent bounds, and to exhibit the required convexity properties with no duality gap. Sample results for isotropic composites are reported and discussed.Facultad de Ingenierí

Influence of metallic inclusions on the electromechanical response of ferroelectric ceramics

Theoretical estimates are given for the overall dissipative response of ferroelectric ceramics with random dispersions of metallic inclusions under arbitrary loading histories. The fer- roelectric behavior of the matrix is described via a stored energy density and a dissipation potential in accordance with the theory of generalized standard materials. An implicit time- discretization scheme is used to generate a variational representation of the overall response in terms of a single incremental potential. Estimates are then generated by constructing se- quentially laminated microgeometries of particulate type whose overall incremental potential can be computed exactly. Because they are realizable, by construction, these estimates are guaranteed to conform with any material constraints, to satisfy all pertinent bounds, and to exhibit the required convexity properties with no duality gap. Sample results for isotropic composites are reported and discussed.Facultad de Ingenierí

Bebidas fermentadas en base a "maíz negro" Zea Mays L. Poaceae, con el eco tipo racimo de uva y la variedad mishca de la serranía ecuatoriana

La presente investigación tiene por objeto el aprovechamiento del maíz como suplemento altamente nutricional y por su gran contenido de compuestos fenólicos especialmente antocianinas y taninos, y su empleo en la elaboración de bebidas fermentadas. Las semillas de maíz negro ―racimo de uva‖ y maíz blanco ―mishca‖ fueron adquiridas en la provincia de Imbabura cantón Cotacachi. El estado de madurez de las plantas fue de 180 días. El saborizante escogido es extraído de los conos femeninos de la planta de lúpulo (Humulus lupulus).Se trabajó con dos tipos de muestras una solo a base de maíz negro y otra con maíz blanco y negro. Se hidrató al maíz negro por 24 horas y al maíz blanco por 48 horas, se germinó por 7 días a las 2 variedades y se lo secó por 24 horas a 65 ºC

Recent changes of chinese economy: impacts on trade relations with Latin America

A expansão das relações econômicas entre a China e os países de América Latina está se desenvolvendo em um marco de fortes transformações no cenário internacional, que alteram o esquema bipolar de comércio existente durante as décadas anteriores. A China tem se posicionado como o principal país manufatureiro e exportador do mundo, deslocando tradicionais centros de acumulação de capital e desenvolvimento tecnológico, como os Estados Unidos e a União Europeia (UE), no fornecimento de diversos bens de capital e insumos. Embora essa realidade possa oferecer oportunidades para os países da região no curto prazo, também apresenta desafios no longo prazo que, se não forem devidamente enfrentados, podem levar ao aumento de sua vulnerabilidade externa estrutural. Neste artigo, analisam-se os impactos que afetam de forma direta e indireta os países latino-americanos que mais comercializam com a China; particularmente, a Argentina e sua relação com o Brasil.The expansion of economic relations between China and Latin American countries may offer opportunities in the short term, as seen in exports of primary products and improved terms of trade. However, it also means challenges for the long term, that in case of not being properly confronted, can lead to worse structural external vulnerability. In this work we analyze those impacts that affect directly and indirectly the countries of the region that trade with China, and particularly the case of Argentina and its relationship with Brazil.Fil: Bekerman, Marta. Universidad de Buenos Aires. Facultad de Ciencias Económicas. Instituto de Investigaciones Económicas. Centro de Estudios de la Estructura Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Dulcich, Federico Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Económicas. Instituto de Investigaciones Económicas. Centro de Estudios de la Estructura Económica; ArgentinaFil: Moncaut, Nicolás Cristian. Universidad de Buenos Aires. Facultad de Ciencias Económicas. Instituto de Investigaciones Económicas. Centro de Estudios de la Estructura Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin