Online forms as a telematics tool to interact with students

Given that the process of adapting to the European Higher Education Area affects both the teaching-learning methodology as well as its assessment, this could be the perfect opportunity for teachers and students to take full advantage of ICT. This article presents a tool based on the Google Docs application that enables interaction with students, including taking online exams quickly and easily. The tool and has already been used successfully in the Introduction to Microeconomics in the Managerial Sciences Degree at the University of Valencia. The main advantage this tool offers in comparison with the Virtual Classroom is how easy it is to use and that it is not restricted to enrolled students.Teaching, tool, ICT

A platform for teaching in Economics

The fact that the Bologna process involves significant changes in teaching and that teachers are alone in carrying out these changes, encouraged a group of professors from different Spanish universities to present the opportunity / need for professors to exchange views and experiences in teaching, as is done in the field of research. All of this took place at the Conferences on Teaching held in Granada. This article reviews the main results of this teaching experience.Teaching, Conferences, EHEA

Social inertia in collaboration networks

This work is a study of the properties of collaboration networks employing the formalism of weighted graphs to represent their one-mode projection. The weight of the edges is directly the number of times that a partnership has been repeated. This representation allows us to define the concept of "social inertia" that measures the tendency of authors to keep on collaborating with previous partners. We use a collection of empirical datasets to analyze several aspects of the social inertia: 1) its probability distribution, 2) its correlation with other properties, and 3) the correlations of the inertia between neighbors in the network. We also contrast these empirical results with the predictions of a recently proposed theoretical model for the growth of collaboration networks.Comment: 7 pages, 5 figure

Soot temperature characterization of spray a flames by combined extinction and radiation methodology

[EN] Even though different optical techniques have been applied on 'Spray A' in-flame soot quantification within Engine Combustion Network in recent years, little information can be found for soot temperature measurement. In this study, a combined extinction and radiation methodology has been developed with different wavelengths and applied on quasi-steady Diesel flame to obtain the soot amount and temperature distribution simultaneously by considering self-absorption issues. All the measurements were conducted in a constant pressure combustion chamber. The fuel as well as the operating conditions and the injector used were chosen following the guidelines of the Engine Combustion Network. Uncertainty caused by wavelength selection was evaluated. Additionally, temperature-equivalence ratio maps were constructed by combining the measurements with a 1D spray model. Temperature fields during the quasi-steady combustion phase show peak temperatures around the limit of the radiation field, in agreement with a typical diffusion flame structure. Effects of different operating parameters on soot formation and temperature were investigated. Soot temperature increases dramatically with oxygen concentration, but it shows much less sensitivity with ambient temperature and injection pressure, which on the other hand have significant effects on soot production. (C) 2019 The Combustion Institute. Published by Elsevier Inc. All rights reserved.This study was partially funded by the Ministerio de Economia y Competitividad from Spain in the frame of the CHEST Project (TRA2017-89139-C2-1-R) and China Postdoctoral Science Foundation (2018M642176). This study was also partially supported by State Key Laboratory of Engines, Tianjin University.Xuan, T.; Desantes J.M.; Pastor, JV.; García-Oliver, JM. (2019). Soot temperature characterization of spray a flames by combined extinction and radiation methodology. Combustion and Flame. 204:290-303. https://doi.org/10.1016/j.combustflame.2019.03.02329030320

Combinatorial approach to Modularity

Communities are clusters of nodes with a higher than average density of internal connections. Their detection is of great relevance to better understand the structure and hierarchies present in a network. Modularity has become a standard tool in the area of community detection, providing at the same time a way to evaluate partitions and, by maximizing it, a method to find communities. In this work, we study the modularity from a combinatorial point of view. Our analysis (as the modularity definition) relies on the use of the configurational model, a technique that given a graph produces a series of randomized copies keeping the degree sequence invariant. We develop an approach that enumerates the null model partitions and can be used to calculate the probability distribution function of the modularity. Our theory allows for a deep inquiry of several interesting features characterizing modularity such as its resolution limit and the statistics of the partitions that maximize it. Additionally, the study of the probability of extremes of the modularity in the random graph partitions opens the way for a definition of the statistical significance of network partitions.Comment: 8 pages, 4 figure

The importance of early parenting for later child outcomes: A study with Spanish families with children with disabilities

Children with different disability conditions have varied developmental trajectories, which perhaps influences parent-child interaction. For these and all infants, an optimal home environment that includes good parenting and positive parent-child interactions predicts better developmental outcomes (Spiker et al., 2005). Interventions using a family-centered, parenting-focused approach result in better parenting behavior that contributes to improved early child development (Avellar & Suplee, 2013; Roggman & Cardia, 2016). Information on parent-child interaction patterns is needed to guide intervention in natural contexts of families (Fuligni & Brooks-Gunn, 2013). Parent-child interaction data were collected from 44 mothers and 35 fathers interacting with their children (23 to 47 months) who had a disability and were in one of eight Spanish Early Interventions Centers. Mothers and fathers, separately, auto-recorded 10-minute play sessions at home. Parental interactions were assessed using PICCOLO (Roggman et al., 2013), a standardized measure of parenting. Two independent observers coded the interactions; strong intra-class correlation coefficients were found (.82 to .97 for mothers, .77 to .89 for fathers). The BSID-III scales (Bayley, 2015) assessed children’s development. Mothers scored slightly higher than did fathers. Scores varied by PICCOLO domains but were consistent with other PICCOLO studies of typical developing children (Roggman et al., 2013). Mother and father’s scores correlated indicating that the higher the scores of mothers in any dimension correlated with those of the parents combined. Positive significant Pearson correlations were found between parenting and child’s development with different patterns of father and mother domains predicting better language and cognitive outcomes. Although barriers to optimal parenting need further investigation, PICCOLO can be a useful tool to support optimal parenting.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Effect of laser induced plasma ignition timing and location on Diesel spray combustion

[EN] An experimental study about the influence of the local conditions at the ignition location on combustion development of a direct injection spray is carried out in an optical engine. A laser induced plasma ignition system has been used to force the spray ignition, allowing comparison of combustion's evolution and stability with the case of conventional autoignition on the Diesel fuel in terms of ignition delay, rate of heat release, spray penetration and soot location evolution. The local equivalence ratio variation along the spray axis during the injection process was determined with a 1D spray model, previously calibrated and validated. Upper equivalence ratios limits for the ignition event of a direct injected Diesel spray, both in terms of ignition success possibilities and stability of the phenomena, could been determined thanks to application of the laser plasma ignition system. In all laser plasma induced ignition cases, heat release was found to be higher than for the autoignition reference cases, and it was found to be linked to a decrease of ignition delay, with the premixed peak in the rate of heat release curve progressively disappearing as the ignition delay time gets shorter. Ignition delay has been analyzed as a function of the laser position, too. It was found that ignition delay increases for plasma positions closer to the nozzle, indicating that the amount of energy introduced by the laser induced plasma is not the only parameter affecting combustion initiation, but local equivalence ratio plays a major role, too. (C) 2016 Elsevier Ltd. All rights reserved.The authors acknowledge that this research work has been partly funded by the Government of Spain under the project HiR-eCo TRA2014-58870-R and grant BES-2015-072119. The equipment used in this work has been partially supported by FEDER project ICTS-2012-06, framed in the operational program of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain.Pastor, JV.; García-Oliver, JM.; García Martínez, A.; Pinotti, M. (2017). Effect of laser induced plasma ignition timing and location on Diesel spray combustion. Energy Conversion and Management. 133:41-55. https://doi.org/10.1016/j.enconman.2016.11.054S415513

An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays

Schlieren imaging has helped deeply characterize the behavior of Diesel spray when injected into an oxygen-free ambient. However, when considering the transient penetration of the reacting spray after autoignition, i.e. the Diesel flame, few studies have been found in literature. Differences among optical setups as well as among experimental conditions have not allowed clear conclusions to be drawn on this issue. Furthermore, soot radiation may have a strong effect on the image quality, which cannot be neglected. The present paper reports an investigation on the transient evolution of Diesel flame based upon schlieren imaging. Experimental conditions have spanned values of injection pressure, ambient temperature and density for typical Diesel engine conditions. An optimized optical setup has been used, which makes it possible to obtain results without soot interference. Based on observations for a long injection event (4 ms Energizing Time), the analysis has resorted to extensive comparison of inert and reacting sprays parameters, which have made it possible to define different phases after autoignition. Shortly after autoignition, axial and radial expansion of the spray have been observed in terms of tip penetration and radial cone angle. After that, during a stabilization phase, the reacting spray penetrates at a similar rate as the inert one. Later, the reacting spray undergoes an acceleration period, where it penetrates at a faster rate than the inert one. Finally, the flame enters a quasi-steady penetration phase, where the ratio of reacting and inert penetration stabilizes at a nearly constant value. The duration of the reacting spray penetration stages shows modifications when varying engine parameters such as air temperature, air density, injection pressure, and nozzle diameter. However, the proportionality between reacting and inert penetration has been observed to depend mainly on temperature, in agreement with observed reductions in entrainment when shifting from inert to reacting conditions. (C) 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.This work was partially funded by the Spanish Ministry of Science and Technology through the "EFFICIENT AND CLEAN COMBUSTION IN COMPRESSION IGNITION ENGINES USING THE DUAL-FUEL CONCEPT" Project (TRA2011-26359). Mr. Francisco J. Briceno wishes to acknowledge financial support through a PhD studies Grant (AP2008-02231) also sponsored by the Spanish Ministry of Education and Science. Last, but not least, authors would like to express their gratitude to Jose Enrique del Rey for his enthusiasm, proactiveness and help during data acquisition.Desantes Fernández, JM.; Pastor, JV.; García Oliver, JM.; Briceño Sánchez, FJ. (2014). An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays. Combustion and Flame. 161(8):2137-2150. https://doi.org/10.1016/j.combustflame.2014.01.022S21372150161

Effect of hydrogen addition on the OH* and CH* chemiluminescence emissions of premixed combustion of methane-air mixtures

[EN] Chemiluminescence emissions measurements of OH* and CH* are used to characterize the combustion of blends of methane and hydrogen in air in a constant volume combustion bomb, with two sets of initial conditions. The combined results of combustion development cover from 0.1 to 2.5 MPa. Burning velocity, heat release and unburned/burned gas temperatures are obtained from the pressure by using a two-zone thermodynamic combustion diagnostic model. Intensity of OH* and CH* increases with the initial temperature and the percentage of hydrogen, in parallel with the usual increase in burning velocity. The timings of the peaks of OH* and CH* chemiluminescence emissions are found to correlate respectively with the maximum rate of heat release and flame temperature. These results show that both chemiluminescence signals can be used to monitorize the burning process in combustion devices operating in the pressure range studied.Reyes, M.; Tinaut, F.; Giménez, B.; Pastor, JV. (2018). Effect of hydrogen addition on the OH* and CH* chemiluminescence emissions of premixed combustion of methane-air mixtures. International Journal of Hydrogen Energy. 43(42):19778-19791. https://doi.org/10.1016/j.ijhydene.2018.09.005S1977819791434