Experiencias de cátedra en las clases de física de primer curso de Escuelas Técnicas

We have performed a set of lecture room experiences in a Physics course at the Escuela Universitaria de Informática, of the Universidad Politécnica de Valencia; we have studied the effects produced on the students. This paper shows that we can prepare and perform this method easily, and also its low cost. On the other hand, the general assessment of the students is positive, and it is particularly helpful to improve the motivation and the understanding of the concepts

Relaxation in non-Markovian models: From static to dynamic heterogeneity

[EN] Glass transition processes have often been explained in terms of wide distributions of relaxation times. By means of a simple stochastic model we here show how dynamic heterogeneity is the key to the emergence of the glass transition. A non-Markovian model representing a small open region of the amorphous material was previously shown to reproduce the time and thermal characteristic behavior of supercooled liquids and glasses. Due to the interaction of the open regions with their environment, the temperature dependence of the equilibrium relaxation times differs from the featureless behavior of the relaxation times of closed regions, whose static disorder does not lead to a glass transition, even with wider distributions of equilibrium relaxation times. The dynamic heterogeneity of the open region produces a glass transition between two different regimes: a faster-thanArrhenius and non-diverging growth of the supercooled liquid relaxation times and an average Arrhenius behavior of the ideal glass. The Kovacs' expansion gap was studied by evaluating the nonequilibrium distribution of relaxation times after the temperature quenches.Funding for open access charge: CRUE-Universitat Polit`ecnica de Val`encia. RSS and JMM acknowledge the Spanish Ministry of Science, Innovations and Universities through the RTI2018-097862-B-C21 Project (including the FEDER financial support). CIBER-BBN is an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER Actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund.Torregrosa Cabanilles, C.; Molina Mateo, J.; Sabater I Serra, R.; Meseguer Dueñas, JM.; Gómez Ribelles, JL. (2022). Relaxation in non-Markovian models: From static to dynamic heterogeneity. Journal of Non-Crystalline Solids. 576. https://doi.org/10.1016/j.jnoncrysol.2021.12124512124557

Results of a university experience, comparing face-toface, online and hybrid teaching in a context of Sarscov19

[EN] The irruption of sarscov19 in the spring of 2020 was a challenge for everyone, particularly university teaching, where solutions had to be improvised urgently. Technological resources and online teaching played a fundamental role, and the involvement of students, teachers and administration led to an acceptable outcome. After the first impact of the pandemic, new alternatives compatible with the protocols of social distancing and health security were proposed in the planning for the academic year 2020-2021. As in many other universities, a synchronous hybrid learning (SHL) model was offered at the Universitat Politècnica de València (UPV), combining online learning and face-to-face (F2F) activities. In the SHL model, some students attended classes in-person (the room capacity limited the number according to the minimum distances between people required) and stream for the rest of the students, who followed the class simultaneously. In addition, the classes were recorded to enable their asynchronous use. SHL was only used when the conditions were favourable. Vulnerable teachers were teaching entirely online in their groups. When the number of students in a group was small enough, teaching was fully F2F, maintaining the online option only for vulnerable or confined students. The laboratory practices followed a similar hybrid scheme. The tutorials were attended by email or videoconference, and the exams were preferably in-person, with ad hoc solutions in the cases of confined or vulnerable students. Between February and June 2021, a pilot experience was carried out in the Electricity course of the degree in Electronic Engineering and Industrial Automation at the UPV. Three groups were taught with a different methodology: online, SHL and F2F teaching. Planning, academic resources, and evaluation were the same in the three groups. All three followed active flipped classroom methods. In this paper, the student's academic outcomes and the results of opinion surveys conducted on the activities are presented. Results are analysed in terms of the three groups/methodologies showing reasonable doubts about the SHL model where, the academic results and the student's opinions are significantly lower than the other two methodologies. These results could help to decide the best methodological solution if we had a similar situation in the future.Authors would like to thank the Institute of Education Sciences of the Universitat Politècnica de València (Spain) for supporting the Teaching Innovation Group e-MACAFI and for the financial support through PIME Project PIME 20-21/220 and PIME Project PIME/2018/B25.Tort-Ausina, I.; Gómez-Tejedor, J.; Molina Mateo, J.; Riera Guasp, J.; Meseguer Dueñas, JM.; Martín-Cabezuelo, R.; Vidaurre, A. (2022). Results of a university experience, comparing face-toface, online and hybrid teaching in a context of Sarscov19. IATED. 896-905. https://doi.org/10.21125/edulearn.2022.025889690

Estudio comparado del rendimiento de los alumnos de primer curso procedentes de C.O.U. frente a los alumnos procedentes de F.P.

De los 450 alumnos de nuevo ingreso que actualmente se matriculan en las titulaciones de Ingeniería Técnica de Informática de Gestión (ITIG) o de Sistemas (ITIS,) en la Escuela Universitaria de Informática de la Universidad Politécnica de Valencia, 135 proceden de Formación Profesional (FP), mientras que la mayor parte del resto han cursado previamente el Curso de Orientación Universitaria (COU). Esta distinta procedencia provoca una importante heterogeneidad en el alumnado, pues mientras se constata, por ejemplo, una mayor habilidad de los alumnos procedentes de F.P. en algunas prácticas de laboratorio, también se evidencian en estos últimos, unas mayores carencias en lo que a conocimientos básicos se refiere, especialmente en Matemáticas. En este trabajo se compara el rendimiento académico de los alumnos de nuevo ingreso procedentes de COU frente al de los procedentes de FP, durante los cuatro cursos de vigencia del actual plan de estudios. Dado que los datos del estudio reflejan unos índices de fracaso académico muy superiores en los alumnos procedentes de FP que en los de COU, desde el curso 96-97, la Escuela decidió implantar en el primer cuatrimestre, una asignatura optativa, Elementos de Matemáticas, recomendada para los alumnos procedentes de F.P., con el fin de mitigar esa falta de conocimientos básicos. Los resultados del primer curso de implantación reflejan una cierta mejora sobre los cursos anteriores

Active methods in electricity and magnetism courses: Influence of degree, academic level and gender on student performance

[EN] The performance of first-year students in electromagnetism (E&M) courses of different engineering degrees at a Spanish public university was measured using the Brief Electricity and Magnetism Assessment (BEMA), a standard research-based instrument to assess students' understanding after attending introductory courses in electricity and magnetism. In all cases, Flipped classroom (FC) built on information and communications technology was used. The objective of this paper is to analyse if the gain in the BEMA pre and post-test results is influenced by several factors such as the degree, the students' academic grade, and gender. Moreover, as some studies have shown that the students' retention of the concepts was significantly stronger in active learning than in traditional approaches, a third BEMA test was performed by the students to analyse the long-term retention gain dependence on the same factors. Students from different engineering degree programs were asked to complete two BEMA tests during the course and a third one after a few months. ANOVA tests were used to analyse the existence of significant differences in gain between student degree programs, student academic level and student gender. Results have shown no differences in the BEMA performance by degree program, but significant differences were found by academic level and gender. Retention did not depend on the degree course but on the academic level. Mean gain value by academic level, and gender was obtained and concluded that the best students presented the best gain results and that gain depends on the students' gender: males outperformed females in the BEMA tests, although there were no significant differences in the course grades. It is thus necessary to understand these differences and to implement measures in daily teaching work to improve women's performance.Authors would like to thank the Instituto de Ciencias de la Educacion (ICE) in the Universitat Politecnica de Valencia for their help, through the Innovation and Educational Quality Program and for supporting the team of the Innovacion en Metodologias Activas para el Aprendizaje de la Fisica (e-MACAFI) . This work has been supported by the UPV through the Project of Innovation and Educational Improvement Program (Projects PIME/18-19/76, PIME/18-19/88 and PIME/20-21/220 Convocatoria de Proyectos de Innovacion y Convergencia de la UPV) .Serrano, M.; Vidaurre, A.; Meseguer-Dueñas, JM.; Tort-Ausina, I.; Quiles Casado, SDLS.; Sabater I Serra, R.; García-Sanchez, T.... (2023). Active methods in electricity and magnetism courses: Influence of degree, academic level and gender on student performance. Heliyon. 9(10):1-15. https://doi.org/10.1016/j.heliyon.2023.e2049011591

Effect of the use of videos in the pre-class preparation of laboratory sessions taught by flip teaching

[EN] Nowadays, it is well stablished the effectiveness of flip teaching in different areas. Video is widely used as a pre-class learning material and it is progressively replacing text-document materials. The students, 70 in total, are enrolled in the laboratory practice of the subject of Physics (Bachelor¿s Degree: Industrial Electronics and Automation Engineering) at the Universitat Politècnica de València. Student¿s perception data were collected from the results of a survey. Students were asked about the usefulness of the videos and the in-class work, paying special attention to the roll of the instructor in relation to the flip teaching methodology and the pre-class material. The students were divided into two groups. In one of them, the videos were recorded by the same instructor present at the lab session, whereas the other group, the videos used were recorded by instructors different from the instructor present at the lab. The results indicate that students feel that the videos are very useful, rather than the written documents. They attribute a high value to the instructor in the lab session as they feel more confident with their work and they can ask for help when needed. They value positively the possibility of work autonomously. Small differences have been found in the opinion of both groups being the higher in the question that concerns the preference of the videos respect to the text.This work has been supported by the Universitat Politècnica de València through the Project of Innovation and Educational Improvement Program (Projects PIME/2018/B26 and PIME/2018/B25 Convocatoria de Proyectos de Innovación y Convergencia).Meseguer Dueñas, JM.; Quiles Casado, SDLS.; Sabater I Serra, R.; Serrano, M.; Gómez-Tejedor, J.; García-Sánchez, TM.; Tort-Ausina, I.... (2020). Effect of the use of videos in the pre-class preparation of laboratory sessions taught by flip teaching. Iated. 6107-6112. https://doi.org/10.21125/inted.2020.1654S6107611

Semicrystalline ordering in polymeric systems simulated by Bond Fluctuation Model

Arresting of segmental mobility in polymer systems on cooling from the melt was simulated by means of the Bond Fluctuation Model. In order to represent the behaviour of the system, three potentials were included: a Lennard-Jones potential, a bond length potential and a bond angle potential. The effect of the bond angle and bond length potential combination is to stretch the chains, while the Lennard-Jones potential leads to a lack of free volume which appears when temperature decreases. So, when a cooling ramp is applied, depending on the balance of these potentials, the system shows a transition in which molecules densely pack or, on the contrary, remains amorphous. Therefore, the choice in the weighting of these three potentials is a key point to simulate a physical system by using the Bond Fluctuation Model. © 2010 Elsevier Ltd. All rights reserved.The authors would like to acknowledge the support provided by the Conselleria d'Educacio of the Generalitat Valenciana through the GV/2009/033 project. This work was supported by the computer-time grant (No. 2003014) of the Centre de Ressources Informatiques de Haute Normandie (CRIHAN).Molina Mateo, J.; Arnoult, M.; Saiter, JM.; Meseguer Dueñas, JM.; Gómez Ribelles, JL. (2011). Semicrystalline ordering in polymeric systems simulated by Bond Fluctuation Model. Polymer. 52(2):571-576. https://doi.org/10.1016/j.polymer.2010.12.002S57157652

Crystallization kinetics of poly(ethylene oxide) confined in semicrystalline poly(vinylidene) fluoride

Polymer blends based on poly(vinylidene fluoride) (PVDF) and poly(ethylene oxide) (PEO) have been prepared to analyze the crystallization kinetics of poly(ethylene oxide) confined in semicrystalline PVDF with different ratios of both polymers. Both blend components were dissolved in a common solvent, dimethyl formamide. Blend films were obtained by casting from the solution at 70 degrees C. Thus, PVDF crystals are formed by crystallization from the solution while PEO (which is in the liquid state during the whole process) is confined between PVDF crystallites. The kinetics of crystallization of the confined PEO phase was studied by isothermal and nonisothermal experiments. Fitting of Avrami model to the experimental DSC traces allows a quantitative comparison of the influence of the PVDF/PEO ratio in the blend on the crystallization behavior. The effect of melting and further recrystallization of the PVDF matrix on PEO confinement is also studied.The authors thank the assistance and advice of Electron Microscopy Service of the UPV. This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-1 and 3-R (including the FEDER financial support); CIBER-BBN is an initiative funded by the VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions, and by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund; FEDER funds through the COMPETE 2020 Programme and National Funds through FCT-Portuguese Foundation for Science and Technology under Strategic Funding UID/FIS/04650/2013; the FCT grant SFRH/BPD/112547/2015 (to C.M.C.); support from the Basque Government Industry Department under the ELKARTEK Program; the doctoral grant from the Programa de Ayudade Investigacion y Desarrollo (PAID) of the Universitat Politecnicade Valencia (to M.N.T.-M.).info:eu-repo/semantics/publishedVersio

Influence of solvent on the network structure formed by free radical polymerization of tri-ethylene glycol dimethacrylate: A dielectric study

Molecular mobility of a series of tri-ethylene glycol dimethacrylate (TrEGDMA) samples polymerized with different amounts of ethyl acetate up to 40% (w/w) as diluent was investigated by dielectric relaxation spectroscopy. In the first measuring scan, the samples show three secondary relaxation processes: a γ process related to the twisting motions within the ethylene glycol moiety as found in the unreacted monomer, a β process assigned to hindered rotations of carboxylic groups residing in non-bonded ends of the monomers linked to the network only by one side of the molecule; and additionally, at higher temperatures, a third process was detected designated as βpol, ascribed to a π flip of the ester unit accompanied by a restricted main chain rearrangement. While the γ and the βpol processes remain in the second scan, the β relaxation goes to extinction due to post-polymerization that took place at the highest temperatures scanned in the previous run, leading to complete polymerization of the network. The strength of γ and β relaxation measured in the first scan increases with the amount of solvent present in the initial mixture, nevertheless, in any case, β relaxation completely disappears in the second scan. © 2009 Elsevier B.V. All rights reserved

Crystallization monitoring of semicrystalline poly(vinylidene fluoride)/1-Ethyl-3-methylimidazolium hexafluorophosphate [Emim][PF6] ionic liquid blends

The electroactive characteristics of poly(vinylidene fluoride) (PVDF) are widely and increasingly being used in technological applications, where controlling the crystallization of the PVDF is of utmost importance. The nucleation and growth of crystals in the β or γ electroactive phases, or in the nonelectroactive α phase, depends on a number of factors that, despite the studies carried out, are still to be properly understood, in particular, when blended with specific active fillers. In this context, the crystallization of PVDF blended with the ionic liquid (IL) 1-ethyl-3-methylimidazolium hexafluorophosphate ([Emim][PF6]) has been analyzed. Both components are capable of crystallizing from the melt. The growth of the crystalline phases of PVDF during isothermal crystallization at different temperatures has been monitored using Fourier transform infrared (FTIR) spectroscopy. The isothermal crystallization kinetics of PVDF and the melting temperatures of both PVDF and IL were characterized by differential scanning calorimetry, and the microstructures of the blends were analyzed by optical and electron microscopy. It is observed for [Emim][PF6]/PVDF blends that the isothermal crystallization from the melt between 120 and 162 °C produces PVDF crystallites in the β and γ electroactive phases, while the formation of α-phase crystals is nearly suppressed. The morphology of the blends is altered by the addition of IL, which results in the separation of solid phases at room temperature. In addition, [Emim][PF6] remains liquid when mixed with the amorphous PVDF chains due to the cryoscopic descent.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019. The authors thank FEDER funds through the COMPETE 2020 Program and National Funds through FCT under the projects PTDC/BTM-MAT/28237/2017, PTDC/EEI-SII/5582/2014, and PTDC/FIS-MAC/28157/2017. D.M.C. thank the FCT for grant SFRH/BPD/121526/2016 and C.M.C. for the Investigator FCT Contract 2020.04028.CEECIND. The work of the Spanish groups has been funded by the Spanish State Research Agency (AEI) through the PID2019-106099RB-C41/AEI/10.13039/501100011033 project and from the Basque Government Industry and Education Departments under the ELKARTEK and PIBA (PIBA-2018-06) programs, respectively. CIBER-BBN is an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER Actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund