La aplicación TurningPoint como herramienta de aprendizaje transformacional en los procesos educativos

The educational convergence project driven by the European Higher Education Area (EHEA) has created new teaching methods and evaluation processes in university education systems. This new pedagogical approach generates an unquestionable opportunity for different segments of the university community see ICTs as an essential tool of the procedure of educational content development, which facilitate the teaching-learning process. This article presents the TurningPoint tool, which focuses on promoting teacher-student interactions, facilitating participation and ongoing assessment. This tool has advantages over other existing applications because of its variety of utilities and potential use. Moreover, it has been successfully used in several programs promoted by the Faculty of Economics of the University of Valencia

Optimization of spray break-up CFD simulations by combining Sigma-Y Eulerian atomization model with a response surface methodology under diesel engine-like conditions (ECN Spray A)

[EN] This work evaluates the performance of the Sigma-Y Eulerian atomization model at reproducing the internal structure of a diesel spray with a special focus on Sauter Mean Diameter (SMD) predictions. Modeling results have been compared to x-ray radiography measurements [21,24,38] which provided unique data within dense spray region. The first step corresponds to accurately reproduce the large scale spray dispersion. Among different RANS turbulence models, the standard k-s with the round jet corrected CIE value (1.60), has shown the best performance, as shown in [12]. Then, the study is devoted to the application and optimization of the predicted interphase surface density (E). In this work, a combination of CFD modeling and the statistical Design of Experiments (DOE) technique known as Response Surface Method (RSM) is applied in order to improve Sauter Mean Diameter (SMD) predictions from E equation compared to experimental measurements. In the investigation, two different optimizations are conducted for the three modeling parameters involved in the equation, following a Central Composite Design (CCD), leading to 15 simulations for each one. After that, both optimum sets of values are validated to assure the accuracy of the method and it is decided the best choice. Finally, different injection and ambient conditions are simulated, with those selected values, providing a remarkable improvement in the modeling performance.Authors acknowledge that part of this work was possible thanks to the Programa de Ayudas de Investigacion y Desarrollo (PAID 2013 3198) of the Universitat Politecnica de Valencia. Also this study was partially funded by the Spanish Ministry of Economy and Competitiveness in the frame of the COMEFF (TRA2014-59483R) project.Pandal-Blanco, A.; Payri, R.; García-Oliver, JM.; Pastor Enguídanos, JM. (2017). Optimization of spray break-up CFD simulations by combining Sigma-Y Eulerian atomization model with a response surface methodology under diesel engine-like conditions (ECN Spray A). Computers & Fluids. 156:9-20. doi:10.1016/j.compfluid.2017.06.022S92015

Rethinking the logistic approach for population dynamics of mutualistic interactions

arXiv:1305.5411© 2014 Elsevier Ltd. Mutualistic communities have an internal structure that makes them resilient to external perturbations. Late research has focused on their stability and the topology of the relations between the different organisms to explain the reasons of the system robustness. Much less attention has been invested in analyzing the systems dynamics. The main population models in use are modifications of the r-. K formulation of logistic equation with additional terms to account for the benefits produced by the interspecific interactions. These models have shortcomings as the so-called r-. K formulation diverges under some conditions. In this work, we introduce a model for population dynamics under mutualism that preserves the original logistic formulation. It is mathematically simpler than the widely used type II models, although it shows similar complexity in terms of fixed points and stability of the dynamics. We perform an analytical stability analysis and numerical simulations to study the model behavior in general interaction scenarios including tests of the resilience of its dynamics under external perturbations. Despite its simplicity, our results indicate that the model dynamics shows an important richness that can be used to gain further insights in the dynamics of mutualistic communities.We have received partial financial support from the Spanish Ministry of Economy (MINECO) under projects MTM2012-39101, MODASS (FIS2011-24785), LIMITES (CGL2009-07229), and AdAptA(CGL2012-33528); from the project PGUI of Comunidad de MadridMODELICO-CM/S2009ESP-1691 and from the EU Commission through projects EUNOIA and LASAGNE. J.J.R. acknowledges funding from the Ramón y Cajal program of MINECO.N

Detection of Parked Vehicles using Spatio-temporal Maps

This paper presents a video-based approach to detect the presence of parked vehicles in street lanes. Potential applications include the detection of illegally and double-parked vehicles in urban scenarios and incident detection on roads. The technique extracts information from low-level feature points (Harris corners) to create spatiotemporal maps that describe what is happening in the scene. The method neither relies on background subtraction nor performs any form of object tracking. The system has been evaluated using private and public data sets and has proven to be robust against common difficulties found in closed-circuit television video, such as varying illumination, camera vibration, the presence of momentary occlusion by other vehicles, and high noise levels. © 2011 IEEE.This work was supported by the Spanish Government project Movilidad y automocion en Redes de Transporte Avanzadas (MARTA) under the Consorcios Estrategicos Nacionales de Investigacion Tecnologica (CENIT) program and the Comision Interministerial Ciencia Y Tecnologia (CICYT) under Contract TEC2009-09146. The Associate Editor for this paper was R. W. Goudy.Albiol Colomer, AJ.; Sanchis Pastor, L.; Albiol Colomer, A.; Mossi García, JM. (2011). Detection of Parked Vehicles using Spatio-temporal Maps. IEEE Transactions on Intelligent Transportation Systems. 12(4):1277-1291. https://doi.org/10.1109/TITS.2011.2156791S1277129112

A computational analysis of local flow for reacting Diesel sprays by means of an Eulerian CFD model

[EN] An implementation and validation of the coupled Sigma-gamma ADF model is presented in this work for reacting Diesel spray CFD simulations under a RANS turbulence modeling approach. An Approximated Diffusion Flamelet (ADF) model Michel et al. (2008) implemented in the OpenFOAM CFD open-source library by Winklinger (2014)15 fed with the spray description, i.e. mixing formation process, provided by the Sigma-gamma Eulerian atomization model Garcia-Oliver et al. (2013). In the present investigation, the Engine Combustion Network Spray A reference configuration is used for validation. Specifically, the model can provide accurate predictions of typical reacting spray metrics, such as the ignition delay and the lift-off length. Moreover, the internal structure is also fairly reproduced in terms of quasi-steady spatial distribution of formaldehyde and OH, related with low and high temperature reactions respectively. Additionally, modeling results have been compared to recent Particle image velocimetry (PIV) measurements Garcia-Oliver et al. (2017) under both inert and reacting conditions. Flow response to heat release is quantitatively predicted by the model, both in terms of local velocity increase as well as radial dilation. The model has been used to understand combustion-induced reduction in entrainment, in particular around the lift-off length location. Flow confinement does not seem to influence the global flame behaviour, even though some changes in the local flow hint can be observed when moving from an open to a closed domain. (C) 2017 Elsevier Ltd. All rights reserved.Authors acknowledge that this work was possible thanks to the Programa de Ayudas de Investigation y Desarrollo (PAID-2013 3198) of the Universitat Politecnica de Valencia. Also this study was partially funded by the Spanish Ministry of Economy and Competitiveness in the frame of the COMEFF(TRA2014-59483-R) project. Authors thank Gilles Bruneaux from IFPEN for the interesting suggestions and discussions.Pandal-Blanco, A.; García-Oliver, JM.; Novella Rosa, R.; Pastor Enguídanos, JM. (2018). A computational analysis of local flow for reacting Diesel sprays by means of an Eulerian CFD model. International Journal of Multiphase Flow. 99:257-272. https://doi.org/10.1016/j.ijmultiphaseflow.2017.10.010S2572729

The effect of CO2-3 on the growth of barite {001} and {210} surfaces: An AFM study

The growth of barite {001} and {210} faces from aqueous solutions moderately supersaturated with respect to barite (βbarite ≈ 12 for experiments on {001} surfaces and βbarite ≈ 7 for experiments on {210} surfaces) and bearing different concentrations of carbonate has been studied in situ using an atomic force microscope (AFM). Nanoscopic observations show that, above a certain carbonate concentration threshold in the aqueous solution, the advancement of monolayers (~3.5Å in height) on barite {001} and {210} surfaces is strongly inhibited. However, inhibition never affects the growth of the first monolayer, whose growth rate increases in the presence of carbonate. In contrast, the second monolayer growth rate decreases as the concentration of carbonate in the solution increases. For high carbonate concentrations in the solution, growth stops after the formation of the first monolayer. While on barite {001} faces, the formation of a second monolayer does not occur for carbonate concentrations higher than 0.2 mM, on barite {210} faces the complete inhibition of the second monolayer is observed for carbonate concentrations higher than 0.05 mM. Once growth on {001} or {210} faces is completely inhibited, i.e. such surfaces are in the ‘‘dead zone’’, growth can be recovered by increasing supersaturation. In order to study the recovery behaviour of barite {001} and {210} faces from the ‘‘dead zone’’, an additional series of AFM experiments have been conducted. In these experiments, carbonate-free aqueous solutions with increasing supersaturations with respect to barite were passed over {001} and {210} surfaces previously ‘‘poisoned’’ with carbonate. Our experimental results show that the recovery of growth on barite {001} faces requires an important increase of the solution supersaturation. In contrast, the recovery of barite {210} surface growth does not require any supersaturation increase, but spontaneously occurs in a few minutes. Our observations of inhibition and growth recovery on barite surfaces at a nano-scale are discussed and compared with the descriptions given by the classical crystal growth inhibition models

Combustion modeling in a pressurized gas turbine burner using Large-Eddy Simulations

The research leading to these results has received funding from the European Union's Horizon 2020 Programme under the ESTiMatE project, grant agreement No. 821418. The authors thankfully acknowledge the computer resources at MareNostrum and the technical support provided by Barcelona Supercomputing Center (IM-2020-3-0022, IM-2021-1-0016).García-Oliver, JM.; Pastor Enguídanos, JM.; Olmeda-Ramiro, I.; Both, A.; Mira, D. (2022). Combustion modeling in a pressurized gas turbine burner using Large-Eddy Simulations. 690-699. http://hdl.handle.net/10251/19067769069

LA PRODUCTIVIDAD DEL SISTEMA BANCARIO ESPAÑOL (1986-1992)

The aim of this paper is to analyze the efficiency of the Spanish banking system forthe period since Spain's incorporation into the EC (1986) to the beginning of the Unit Marketin 1993. A new productivity analysis is justified by the deep changes experienced duringthese years in the banking sector as well as by the irnportance of efficiency in a bankingsystem. The study allows us to identify some of the features of the improvement in totalfactor productivity of the Spanish banking firms.Banks' output features and their response to margin reduction process are analyzed.Econometric analysis decomposes firm efficiency determinants. El objetivo del trabajo es analizar la eficienda del Sistema bancario Español en laetapa comprendida entre la incorporación de España a la CEE (1986) y el inicio del mercado único (1993). Las profundas transformaciones que han tenido lugar en estos años en el sector bancario, así como la importancia de un sistema bancario eficiente para cualquier economía, son las principales razones que justifican un nuevo análisis de la productividad. El estudio desarrollado permite identificar algunas de las características del proceso de mejora de la productividad total de los factores en las empresas bancarias españolas. Se analiza la peculiaridad del output bancario, así como su sensibilidad al proceso de reducción de márgenes. Una vez definida la medida de productividad elegida, se descomponen econométricamente los determinantes de las diferencias de las productividades entre entidades.

Analysis of local extinction of a n-heptane spray flame using large-eddy simulation with tabulated chemistry

This work is focused on the study of flame stabilization and local extinction of a spray flame in an atmospheric non-swirled test rig referred to as the CORIA Rouen Spray Burner. This burner shows a double reaction front structure, with an outer laminar diffusion flame and an inner wrinkled partially-premixed flame undertaking local extinction. This unsteady phenomenon is investigated here using large-eddy simulations with a tabulated chemistry method based on steady and unsteady diffusion flamelets with heat loss. A validation of the numerical simulations is conducted first for the carrier and dispersed phase and good agreement with the experimental data is found for mean and fluctuating quantities. The present results were able to predict relevant parameters of the flame like the lift-off length and flame shape. Numerical results evidence some intermittency on the OH concentration with the presence of high values of formaldehyde indicating the existence of localized extinction in the leading edge of the flame. A detailed analysis showed the impact of droplets on the reacting layer and the existence of rich pockets quenching the flame front. Further downstream, it was shown that when the scalar dissipation rate reaches high values near the reaction zone, the flame front becomes thinner and wrinkled until it eventually quenches. The numerical results evidence that the applied tabulated chemistry method is capable of capturing the local extinction and re-ignition events occurring in the inner layer.This work was partially funded by the Spanish Ministerio de Econom´ıa y Competitividad within the frame of the CHEST (TRA2017-89139-C2-1-R) project. BSC also acknowledges the funding from the CoEC project through the European Union’s Horizon 2020 research and innovation programme under grant agreement No 952181. Authors acknowledge the computer resources at Marenostrum and the technical support provided by Barcelona Supercomputing Center (BSC) (IM-2019-3-0025, IM-2020-1-0017, IM-2020-2-0026). Authors also thank the access to the CRSB database kindly provided by Prof. B. Renou.Peer ReviewedPostprint (author's final draft

Gender and grade level differences in self-concept dimensions: study with a Spanish adolescent sample

Este estudio analizó las diferencias de género y curso y el papel predictivo de estas variables en las dimensiones del autoconcepto medidas por el SDQ-II. El cuestionario fue administrado a 2.022 estudiantes de 1º a 4º de ESO. Los resultados revelaron que los chicos puntuaron significativamente más alto en las dimensiones Habilidades Físicas, Apariencia Física, Estabilidad Emocional y Matemáticas, mientras las chicas presentaron puntuaciones más altas en Relaciones con el Mismo Sexo, Relaciones con los Padres, Sinceridad-Veracidad y Verbal, no encontrándose diferencias estadísticamente significativas en la puntuación total del SDQ-II. Además, no se hallaron diferencias de curso estadísticamente significativas en Habilidades Físicas, Relaciones con el Mismo Sexo, Estabilidad Emocional, Matemáticas, Autoestima y Sinceridad-Veracidad, existiendo variaciones en el resto de escalas así como en la puntuación total. Los análisis de regresión logística revelaron que el género y el curso fueron predictores significativos del autoconcepto, aunque los resultados variaron para cada dimensión.This study analyzed gender and grade differences and the predictive role of these variables in the self-concept domains measured by the SDQ-II. The questionnaire was administered to 2.022 secondary school students from Grades 7 to 10. Results revealed that boys scored significantly higher in Physical Ability, Physical Appearance, Emotional Stability and Maths, whereas girls showed higher scores in Same Sex Relations, Parents Relations, Honesty-Trustworthiness and Verbal. No statistically significant differences were found in the total score. Likewise, statistically significant differences were not found in grade level regarding Physical Abilities, Same Sex Relations, Emotional Stability, Maths, General Self and Honesty-Trustworthiness. Statistically significant differences were reported in the remaining domains and in the total score. Logistic regression analyses revealed that gender and grade were significant predictors of self-concept, although results varied for each dimension