Avances en la fabricación de células y módulos fotovoltaicos de silicio en capa fina mediante láser

El láser es un instrumento omnipresente en la fabricación de módulos fotovoltaicos. Los láser estándar para la interconexión monolítica de dispositivos de lámina delgada de a-Si son láser de estado sólido bombeados por diodo (DPSS) emitiendo en longitudes IR (λ=1064 nm) y en VIS (λ=532 nm). En este trabajo mostramos estudios de ablación de algunos materiales fotovoltaicos (óxidos conductores transparentes (OCT) y a-Si) con láser emitiendo en UV en el régimen de nanosegundos (ns). La afección térmica resultante en la ablación es menor, y por tanto se reduciría el riesgo de cortocircuitos en la interconexión monolítica, convirtiendo a las fuentes láser UV como herramientas prometedoras como alternativa a las fuentes estándar. Laser is an essential tool for photovoltaic modules manufacturing. Nowadays DPSS working at IR ( λ=1064 nm) and VIS (λ=532 nm) wavelengths are standard tools for thin film module fabrication. In this work we present ablation studies of some photovoltaic materials (transparent conductive oxides (TCO) and a-Si) using nanoseconds (ns) laser sources emitting in the UV. The thermal affection is minimized, and therefore it would be reduced the short-circuit formation risk in the monolithic interconnection, demonstrating the potential use of ns laser sources emitting in the UV as promising alternative tools to the standard laser sources

A counterfactual impact evaluation of a bilingual program on students’ grade point average at a spanish university

This observational study intends to estimate the causal effects of an English as a Medium of Instruction (EMI) program (as predictor) on students Grade Point Average (GPA) (as outcome) at a particular University in Spain by using a Counterfactual Impact Evaluation (CIE). The need to address the crucial question of causal inferences in EMI programs to produce credible evidences of successful interventions contrasts, however, with the absence of experimental or quasi-experimental research and evaluation designs in the field. CIE approach is emerging as a methodologically viable solution to bridge that gap. The program evaluated here consisted in delivering an EMI program in a Primary Education Teacher Training Degree group. After achieving balance on the observed covariates and recreating a situation that would have been expected in a randomized experiment, three matching approaches such as genetic matching, nearest neighbor matching and Coarsened Exact Matching were used to analyze observational data from a total of 1288 undergraduate students, including both treatment and control group. Results show unfavorable effects of the bilingual group treatment condition. Potential interpretations and recommendations are provided in order to strengthen future causal evidences of bilingual education programs’ effectiveness in Higher Education.This work was supported by the Junta de Andalucía-funded Proyecto de Excelencia: “Análisis y Garantía de Calidad de la Educación Superior Plurilingüe en la Educación Superior de Andalucía [Junta de Andalusia-funded Project of Excelence: Analysis and Warrantee of the Quality of Plurilingual Higher Education in Andalucia] (AGCEPESA; Grant Agreement No. P12-SEJ − 1588)

Feasible glass-melting process assisted by microwaves

This is the peer reviewed version of the following article: Reinosa, JJ, García-Baños, B, Catalá-Civera, JM, López-Buendía, AM, Guaita, L, Fernández, JF. Feasible glass-melting process assisted by microwaves. Int J Appl Glass Sci. 2019; 10: 208 219, which has been published in final form at https://doi.org/10.1111/ijag.13093. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] The advantages of microwave (MW) energy processing have been verified in the sintering of a ceramic frit at a pre-industrial scale. The challenge of achieving high temperature using MW energy at such dimensions was overcome and a mix of natural raw materials was heated until its fluxing point. Changes in dielectric properties of the raw materials mix were also measured in situ with the increase in temperature, being in accordance to thermal processes of a conventional heating process. The properties of the resulting ceramic frit were compared with the same frit obtained by the conventional sintering method. Both frits showed similar thermal behavior regarding DTA-TGA, heating microscopy and XRD (only glassy phase was present). A Raman study confirms the existence of the mentioned glass phase. The application of the frits as glazes were performed and their properties were studied. As a result, glazes with similar properties were obtained which confirms that the MW energy processed frit is suitable for its application as a ceramic glaze.Consejo Superior de Investigaciones Cientificas, Grant/Award Number: CSIC201560E068; Ministerio de Ciencia, Tecnologia e Innovacion Productiva, Grant/Award Number: MAT2017-86450-C4-1-R; Seventh Framework Programme, Daphne Project, Grant/Award Number: 314636Jiménez Reinosa, J.; García-Baños, B.; Catalá Civera, JM.; López-Buendía, ÁM.; Guaita, L.; Fernández, JF. (2019). Feasible glass-melting process assisted by microwaves. International Journal of Applied Glass Science. 10(2):208-219. https://doi.org/10.1111/ijag.13093S20821910

Empirical Comparison of Graph-based Recommendation Engines for an Apps Ecosystem

Recommendation engines (RE) are becoming highly popular, e.g., in the area of e-commerce. A RE offers new items (products or content) to users based on their profile and historical data. The most popular algorithms used in RE are based on collaborative filtering. This technique makes recommendations based on the past behavior of other users and the similarity between users and items. In this paper we have evaluated the performance of several RE based on the properties of the networks formed by users and items. The RE use in a novel way graph theoretic concepts like edges weights or network flow. The evaluation has been conducted in a real environment (ecosystem) for recommending apps to smartphone users. The analysis of the results allows concluding that the effectiveness of a RE can be improved if the age of the data, and if a global view of the data is considered. It also shows that graph-based RE are effective, but more experiments are required for a more accurate characterization of their properties

El género como variable de estudio en las características del juego en voleibol en categoría infantil

El objetivo principal de esta investigación fue analizar las características y rendimiento en la acción del saque en voleibol, en categoría infantil, en función del género. Se empleó una muestra de 2233 saques, correspondientes a la observación de los 32 equipos participantes en el Campeonato España de Selecciones autonómicas en categoría infantil, femenina y masculina. Las variables de estudio fueron: género del equipo, zona de origen de saque, tipo de saque, técnica de golpeo, eficacia del saque, zona a la que se dirige el saque y jugador al que se dirige el saque. Los resultados determinaron una asociación significativa entre las variables origen de saque, tipo de saque, técnica de golpeo y eficacia de saque, con el género de los equipos. Concretamente, contribuyeron positivamente a esta asociación el origen de saque desde zona 1, el saque en salto, el saque flotante y el saque que permite ataque en el género masculino; y el saque desde zona 6, el saque en apoyo, el saque potente, el error de saque, el saque que no permite ataque y el saque punto en el género femenino. Por ello, concluimos que desde etapas de formación encontramos diferencias en las características del saque y su eficacia en función del género, por lo que debemos tener en cuenta dichos resultados en el proceso de entrenamiento de esta acción técnico-táctica. The main aim of this research was to analyze the characteristics and performance of the serve action, in volleyball Under-14 category, by gender. The sample was comprised of 2233 serves, corresponding to the observation of 32 teams participating in the Spanish Championship of Regional Selections, male and female Under-14 categories. The studied variables were: gender, serve zone, serve type, striking technique, serve effectiveness, reception zone and receiver player. The results showed a significant association between the serve zone, serve type, striking technique and serve effectiveness with gender. Specifically, correlated significantly and positively: the serve zone from zone 1, the jump serve, the float serve and serve permits attacking with the male gender; and the serve zone from zone 6, the standing serve, the power serve, serve error, the serve that does not permit attacking and the point serve in the female gender. Therefore, we conclude that, in formative stages we find differences in the characteristics and effectiveness of the serve by gender, we must take into account these results in the training process of this technical-tactical action

Experimental results and modelling of humidity control strategies from greenhouses in continental and coastal setting in the Mediterranean regíon. I : Experimental results and model development.

Experimental strategies for controlling humidity were compared in a greenhouse sited in Madrid, a continental site in the Mediterranean region. Small roof window apertures significantly reduced the relative humidity with only a limited increase in associated energy consumption. A simplified climate model with four energy exchange terms (heating, insolation, losses through structure, and losses through windows) and three mass exchange terms (evapotranspiration, losses through structure, and losses through windows) was validated, allowing relative humidity to be predicted with an error of < 9%. - Se ensayaron una serie de estrategias experimentales para el control de la humedad en un invernadero de Madrid, España. Se comprobó que pequeñas aperturas de la ventana cenital reducían significativamente el nivel de humedad con limitados incrementos del consumo de energía en calefacción. Se validó un modelo climático simplificado con cuatro términos de intercambio de energía (calefacción, radiación solar, pérdidas a través de la cubierta y pérdidas a través de las ventanas) y tres términos de intercambio de humedad (evapotranspiración, pérdidas a través de la cubierta y pérdidas a través de las ventanas), modelo que permitió predecir la humedad relativa con un error inferior al 9%

Metodología de obtención de los coeficientes de sustentación y arrastre para un rango amplio de números de Reynolds y ángulos de ataque para aplicaciones en turbinas eólicas

In research of wind turbine design, often isnecessary to analyze the behavior of different typesof aerodynamic profiles on their blades. Of these,is necessary to know the coefficients of lift anddrag, but this data is not available for all the profileswanted to be used to analyze the turbines.In this paper will be explore an alternative forthe determination of these coefficients and isimplemented the methodology for generatingcurved profile data.En la investigación en diseño de turbinaseólicas, comúnmente es necesario analizar sucomportamiento al usar diferentes tipos de perfilesen sus alabes. De éstos, es necesario conocer suscoeficientes de sustentación y arrastre; sin embargo,estos datos no están disponibles para todos losperfiles con que se desea experimentar.En este artículo se explora una alternativa conla que se cuenta para la determinación de estoscoeficientes y se implementa la metodología para lageneración de los datos de un perfil curvado

Elastic scattering for the system 6Li + p at near barrier energies with MAGNEX

Elastic scattering measurements have been performed for the 6Li+p system in inverse kinematics at the energies of 16, 20, 25 and 29 MeV. The heavy ejectile was detected by the large acceptance MAGNEX spectrometer at the Laboratori Nazionali del Sud (LNS) in Catania, in the angular range between ∼20 and 120 in the laboratory system, giving us the possibility to span almost a full angular range in the center of mass system. Results will be presented and discussed for one of the energies.European Union 262010-ENSA