TCO-free low-temperature p+ emitters for back-junction c-Si solar cells

In this work, we report on the fabrication and characterization of n-type c-Si solar cells whose p+ emitters are based on laser processed aluminum oxide/silicon carbide (Al2O3/SiCx) films. The p+ emitter is defined at the rear side of the cell and it consists of point-like laser-diffused p+ regions with a surface charge induced emitter in between based on the high negative charge located at the Al2O3/c-Si interface. These emitters are fabricated at low temperature (1000 nm) that reach the rear surface of the cell resulting in an excellent back reflector. We fabricated solar cells with distance between p+ regions or pitch ranging from 200 to 350 µm with a front surface based on silicon heterojunction technology. Best efficiency (18.1%) is obtained for a pitch of 250 µm as a consequence of the trade-off between Voc and FF values.Peer ReviewedPostprint (published version

Capital social y políticas públicas: análisis del efecto del programa de coinversión social sobre las organizaciones de la sociedad civil

Este estudio se deriva de la evaluación del Programa de Coinversión Social (PCS), el cual aporta recursos financieros a las Organizaciones de la Sociedad Civil (OSCs) para el desarrollo de grupos vulnerables y con rezago mediante el fomento de su capital social. Para la evaluación, se analizó la relación del capital social con el PCS y el fortalecimiento de las OSCs. Se llevó a cabo un estudio cualitativo y cuantitativo, el primero consistió en entrevistas a profundidad y grupos focales; el segundo en una encuesta con dos instrumentos aplicados a las OSCs y a los beneficiarios. Se utilizó el análisis de componentes principales y la metodología de variables latentes para estimar los aspectos no observables y multidimensionales de los conceptos de capital social y fortalecimiento institucional. Se estimaron dos Modelos de Ecuaciones Estructurales (SEM) para captar la influencia mutua entre los indicadores de ambos conceptos, así como su relación, los cuales generaron resultados similares: el PCS fortalece a las OSCs para el desarrollo de sus proyectos, su capital social se obtiene de esta forma. Las OSCs cuentan con capital social entre sus miembros y su población objetivo, crean redes con otras OSCs donde se identifican e intercambia información y apoyo, y fomentan cohesión social. Se identificaron los elementos que determinan el fortalecimiento institucional y el capital social de las OSCs, su conocimiento podría contribuir a focalizar los apoyos del PCS para el logro de sus objetivos.social capital, Mexico, system of equation model, civil society, evaluation

Thermal applications of biomass in hospitals

The aim of this study was to evaluate the feasibility of using renewable energy from biomass for the production of heat and cold in hospitals, examining the feasibility of establishing such facilities in Extremadura (Spain). In its development, has been taken into account the technical aspects related to the operation of this type of heating, including reliability and maintainability of them, assessing the problems generated by the introduction of renewable energy from biomass in publics buildings. It has been shown that high consumption of hot water and heating systems consume annually make the hospital a great place for the installation of thermal production systems based on biomass, because the necessary demand and its continued operation, promotes amortization. In addition, it was found that promoting the use of renewable energy through biomass, can help create and consolidate a native biomass market, emerging at the beginning of this project and in the consolidation phase at the present time, that eventually will get an economic improvement in rural areas, promoting its development

Procesos de sostenibilidad en España: implicaciones territoriales y urbanas

La ocupación del suelo es una de las variables clave para medir con rigor la sostenibilidad. España tiene todavía uno de los territorios más diversos y, excepcionalmente valiosos de Europa. La calidad de vida actual y de las generaciones futuras, la utilización de los recursos naturales, la biodiversidad, y los propios sectores productivos están determinados por esta ocupación del suelo. Por todo ello, el análisis de los cambios de ocupación es clave para conocer el estado actual y las tendencias en los procesos de sostenibilidad en España. El objetivo de este artículo es describir las consecuencias sociales, económicas y ambientales de los cambios de uso del suelo en España

Numerical simulations of rear point-contacted solar cells pn 2.2 Wcm p-type c-Si substrates

Rear surface of high-efficiency crystalline silicon solar cells is based on a combination of dielectric passivation and point-like contacts. In this work, we develop a 3D model for these devices based on 2.2 Ωcm p-type crystalline silicon substrates. We validate the model by comparison with experimental results allowing us to determine an optimum design for the rear pattern. Additionally, the 3D model results are compared with the ones deduced from a simpler and widely used 1D model. Although the maximum efficiency predicted by both models is approximately the same, large deviations are observed in open-circuit voltage and fill factor. 1D simulations overestimate open-circuit voltage because Dember and electrochemical potential drops are not taken into account. On the contrary, fill factor is underestimated because of higher ohmic losses along the base when 1D analytical model is used. These deviations are larger for relatively low-doped substrates, as the ones used in the experimental samples reported hereby, and poor passivated contacts. As a result, 1D models could mislead to too short optimum rear contact spacing.Peer ReviewedPostprint (published version

Textured PDMS films applied to thin crystalline silicon solar cells

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Front surface texturization is a standard procedure used to improve optical properties of photovoltaic devices. In some particular cases, such as when dealing with ultrathin substrates, common texturization techniques can become unpractical or even unfeasible. Texturized polymer films applied on top of such devices may be used as an alternative. In this article, we report on the development of textured polydimethylsiloxane (PDMS) films to be placed on top of planar crystalline silicon solar cells based on thin substrates (=40 µ m). The PDMS polymer is deposited onto a rough surface (conventional random pyramid textured silicon), cured and detached from it. By scanning electron microscope images, we demonstrate that the dilution of PDMS into toluene helps in a better replica of the master surface. Next, we apply the optimized PDMS films on top of dummy samples based on 10, 20, and 40 µm thick crystalline silicon (c-Si) substrates whose reflectance is significantly reduced after placing the PDMS films. Accurate optical simulations indicate that the optical improvement comes from three mechanisms: higher light transmission into the device, lower reflectance at the c-Si surface, and better light trapping properties at the thin c-Si absorber. Experimental verification of the optical improvement with texturized PDMS films is reported based on 40 µ m thick solar cell, where a short-circuit current density gain of 1.7 mA/cm 2 is observed.This work was funded by MINECO from Spanish government under projects TEC2017-82305-R, ENE2016-78933-C4-1-R, ENE2017-87671-C3-2-R. The work was also supported in part by project REFER COMRDI15-1-0036 funded by ACCIÓ and the European Regional Development Fund (FEDER).Peer ReviewedPostprint (published version

Comedias sueltas del Museo Nacional del Teatro

Copia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 2009Precede al tít.: Comedia famosaPie imprenta tomado del colofónSign.:A-C4, D3Texto a dos col. y reclamo

Building IoT Applications with Raspberry Pi and Low Power IQRF Communication Modules

Typical Internet of Things (IoT) applications involve collecting information automatically from diverse geographically-distributed smart sensors and concentrating the information into more powerful computers. The Raspberry Pi platform has become a very interesting choice for IoT applications for several reasons: (1) good computing power/cost ratio; (2) high availability; it has become a de facto hardware standard; and (3) ease of use; it is based on operating systems with a big community of users. In IoT applications, data are frequently carried by means of wireless sensor networks in which energy consumption is a key issue. Energy consumption is especially relevant for smart sensors that are scattered over wide geographical areas and may need to work unattended on batteries for long intervals of time. In this scenario, it is convenient to ease the construction of IoT applications while keeping energy consumption to a minimum at the sensors. This work proposes a possible gateway implementation with specific technologies. It solves the following research question: how to build gateways for IoT applications with Raspberry Pi and low power IQRF communication modules. The following contributions are presented: (1) one architecture for IoT gateways that integrates data from sensor nodes into a higher level application based on low-cost/low-energy technologies; (2) bindings in Java and C that ease the construction of IoT applications; (3) an empirical model that describes the consumption of the communications at the nodes (smart sensors) and allows scaling their batteries; and (4) validation of the proposed energy model at the battery-operated nodes.This work was supported in part by the University of the Basque Country (UPV/EHU) under projects EHU13/42 and UFI11/28 and by the Basque Government (GV/EJ) under projects CPS4PSS ETORTEK14/10 and Thinking Factory ETORGAI14

A software system to teach economics to secondary school and first year engineering students

[EN] In this paper, we present a graphical user interface which has been devised to teach the basic concepts of economics in secondary schools and first year engineering courses. The application allows students to vary certain parameters and visually observe the effect on the supply and demand curves. The system has been developed in Matlab and employed in a secondary school in Spain. The first results are presented.[ES] Presentamos una interfaz gráfica desarrollada mediante Matlab diseñada para complementar el aprendizaje de los conceptos básicos de economía en Bachillerato, grado superior de ciclos formativos y cursos universitarios de introducción a la economía. La aplicación informática permite que los estudiantes varíen los parámetros de los que dependen las curvas de oferta y demanda, y visualicen el efecto sobre el equilibrio de mercado de estas variaciones. Se presentan los resultados de una primera experiencia de aplicación del programa en enseñanza secundaria en España.García-March, M.; Zacarés, M.; Isidro, J.; Monreal, L.; López-Javier, C.; Arevalillo-Herráez, M. (2009). A software system to teach economics to secondary school and first year engineering students. Modelling in Science Education and Learning. 2:105-113. doi:10.4995/msel.2009.3126SWORD105113

Prácticas de laboratorio para asignaturas relacionadas con la microestructura, durabilidad y corrosión en materiales base-cemento

La llegada del Espacio Europeo de Educación Superior ha traído consigo una importante transformación de las titulaciones que se impartían en la universidad española. Entre estos cambios, destaca la aparición de los másteres universitarios que, entre otros, tienen como objetivo mejorar el grado de especialización de los egresados. Entre ellos, en la Escuela Politécnica Superior de la Universidad de Alicante, se puso en marcha el Máster en Ingeniería de los Materiales, Agua y Terreno. Dentro de este máster hay varias asignaturas que tratan aspectos relacionados con la microestructura, durabilidad y estudio de la corrosión en materiales base cemento, que cuentan con una serie de horas dedicadas a prácticas de laboratorio. En vista de ello, en esta red se ha elaborado una propuesta de prácticas de laboratorio, coordinadas entre esas asignaturas, estableciendo los contenidos cuyo aprendizaje puede ser más efectivo a través de las prácticas de laboratorio y optimizando así el proceso de enseñanza-aprendizaje