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- Preferences for Teaching Materials: A Survey on a Multimodal WorldPublication . Coelho, Luis; Reis, Sara Seabra dos; Coelho, Maria de FátimaIn an age of mass teaching, student-teacher contact time is not always enough to ensure an effective teaching-learning process. For the assimilation of concepts it is necessary that, outside the classroom, without the presence and support of the teacher, the student uses materials that allow to remember and eventually complement the learning during the class and simultaneously facilitate and guide, leading to the achievement of the defined objectives. As technology evolves, study materials and support platforms are increasingly diverse and it is important for the teacher to know which means students use and their motivations. A survey was conducted with a group of students from an undergraduate degree in biomedical engineering from a Portuguese higher education institution in order to understand their study habits and the materials they use when out of the classroom. From the analysis of the answers it was possible to infer that the students show preference for studying in a family environment, alone and using as materials the class notes provided by the teachers. Despite the growing use of videos and other multimodal media, the written, personalized notes and orientations set by the teacher are still the most preferred.
- Preferences For Studying Materials: What Has COVID-19 ChangedPublication . Coelho, Luis; Reis, Sara Seabra dos; Coelho, Maria de FátimaIn a multimodal world the contact time between the teacher and the students is not always sufficient to ensure the effectiveness of the learning process. For the assimilation of concepts, students often endeavor on a search for the materials that best suit their learning needs. With the application of new technologies in teaching, study materials and support platforms are increasingly abundant and diverse. Additionally, recommendation algorithms overwhelm students with several options, sometimes hard to resist and select, especially after the COVID-19 restrictions, where the amount of connected time as increased. In this context, it is important for the teacher, to know which methods and materials the students use when they are autonomously developing their knowledge and skills. A survey was conducted within a group of engineering students at a Portuguese higher education institution with the main goal of characterizing the study habits and the materials that students. The obtained results are here reported and analyzed and compared with previous results from pre-pandemic study.
- An approach to characterize the nanolayer for a nanofluid: Thickness, density and molar massPublication . Iglesias, T.P.; Queirós, A.; Coelho, M.F.The aim of this work is to develop a theoretical approximation to calculate the effective thickness, density and molar mass of the interfacial nanolayer around nanofluid particles. These properties of the nanolayer depend, in general, on temperature, on the nature of the base fluid, the nature of nanoparticles, their geometry and their concentration. The model takes into account all these parameters. This is presented for a general geometry and it is shown that the effective nanolayer molar mass is equal to that of the base fluid. Then, this is particularized for a spherical geometry, which is one of the most usual in literature, and is numerically applied to the aqueous alumina (15 nm) nanofluids at different temperatures and nanoparticle concentrations. The obtained results together with those from the application of the model to some nanofluids from literature, at different temperatures and nanoparticle concentrations, allow providing a general insight into the effective behavior of those nanolayer properties. Finally, it is shown that the model, under its hypothesis, does not support the equation of Pak and Cho except as an approximation.
- Biomedical Students’ Motivation with Project Based Learning: A Case StudyPublication . Reis, Sara Seabra dos; Coelho, Maria De Fátima; Coelho, LuisOne of the teacher’s first goals should be to motivate students to learn. Involving students in the learning process using project-based learning could be a useful and powerful tool to prepare the students for them professional future. As part of a degree course in Biomedical Engineering, from a Portuguese University, students were asked to look at society and identify a possible failure related to the biomedical field. From the identification of this fault, the project consisted in the planning and its possible resolution. In this article we present the case study of a student’s team, whose project was candidate and winner for a national prize in the field of health innovation. Despite the particularization of this case study, the students considered the experience innovative and simultaneously motivating. They also highlighted the added value of a project going beyond the classroom. Therefore, in addition to allowing them to obtain classification to the curricular unit, this type of teaching and learning could have a special impact on civil society.
- Avaliação on-line em contexto de pandemia: Experiência pedagógica no ensino superiorPublication . Coelho, Maria Fátima; Guimarães, Pedro; Queirós, Ângela; Gueiral, Nuno; Iglesias, Teresa P.Pretende-se descrever a prática educativa usada na realização do exame online de Física Experimental, UC do 1.º ano de Engenharia Civil, com recurso às plataformas Moodle e Zoom. Os resultados obtidos na avaliação são comparados aos resultados obtidos em anos anteriores e permitem verificar taxas de aprovação idênticas o que contraria as evidências mostradas por alguns autores.
- Permittivity and electrical conductivity of copper oxide nanofluid (12 nm) in water at different temperaturesPublication . Coelho, M.F.; Rivas, M.A.; Vilão, G.; Nogueira, E.M.; Iglesias, T.P.The effective permittivity and electrical conductivity of copper oxide (12 nm) nanofluids in water are studied. The measurements were carried out at various concentrations (up to 2% in volume) and at six temperatures (from 298.15 K to 348.15 K). Empirical equations were used for describing the conductivity and the permittivity of the experimental data. The study shows the influence of the volume fraction, the temperature on relative permittivity and electrical conductivity. When compared with the previously published values for alumina (15 nm) in water, present results show the influence of the nanoparticle’s nature. The enhancement of both permittivity and electrical conductivity were calculated and their behaviour was analysed. It is discussed whether their positive values can be considered greater than what would be expected. The contributions to permittivity from volume, contrast and interactions are separated. Theoretical models are applied in the study of permittivity and electrical conductivity. The poor predictions of classical models for permittivity are attributed to the positive behaviour of the permittivity change on mixing for these nanofluids. The contributions to electrical conductivity from water and nanoparticles are separated.
- Density of aqueous alumina (15nm) nanofluids at different temperaturesPublication . Queirós, Ângela; Coelho, M. Fátima; Iglesias, Teresa P.(Excerpt of introduction) At nanometric scale the materials present properties distinctively different from those in the bulk. The literature has shown that the main factors involved in the behavior of their thermophysical properties are the size, morphology, and content of nanoparticles, the purity of the base fluid and also the possibility of addition of surfactnts. From a fundamental standpoint, it is discussed whether the positive values of p/pw, fig 1, can be considered greater than what would be expected. (...)
- Stability of nanofluids CuO (40nm) in ethylene glycol or water base fluids with CTAB surfactant for biomedical applicationsPublication . Queirós, Ângela; Coelho, Maria de Fátima; Martins, Andreia; Iglesias, T. P.Abstract In this work, some properties of CuO nanofluids in distilled water and ethylene glycol base fluid were studied, comparing the stability of the nanofluid in samples with and without surfactant and measuring the electrical conductivity as a function of temperature and concentration.
- Sobre una aplicación en Visual. Net para la realización de exámenes virtuales durante la pandemia por CovidPublication . Iglesias, T. P.; Rivas, M.; Queirós, A.; Coelho, M. F.El Tribunal Superior de Xustiza de Galicia, TSXG, avaló recientemente los exámenes virtuales que se realizaron en la Universidad de Vigo debido a la pandemia que se produjo en el segundo cuatrimestre del curso 2019-2020. En este trabajo se analizará el desarrollo y uso de la herramienta en Visual. Net que se utilizó para evaluar una asignatura que se imparte en el segundo cuatrimestre de la Universidad de Vigo. Los resultados de la evaluación obtenidos con esta herramienta respaldan la decisión del TSXG en lo que se refiere a la asignatura mencionada.
- Permittivity of (40 nm and 80 nm) alumina nanofluids in ethylene glycol at different temperaturesPublication . Coelho, Maria de Fátima; Rivas, M.A.; Nogueira, Elisabete Maria; Iglesias, T.P.This article studies the effective permittivity of alumina nanofluids (aluminium oxide) in ethylene glycol. Two nanoparticle sizes (40 nm and 80 nm) were considered and the measurements were carried out at various concentrations (up to 2% in volume) and at six different temperatures (from 298.15 K to 348.15 K). An empirical equation is proposed that allows to obtain the permittivity value at any concentration or temperature in the studied ranges. The influence of the volume fraction, nanoparticle size and the temperature on relative permittivity is shown. When compared to the previous published values for alumina (40 nm) in water, current results show the influence of the base fluid. The enhancement of permittivity was calculated, and its behaviour was analysed. Smaller sized particles have the highest values of permittivity and enhancement. Theoretical models in the study of permittivity are applied. The poor predictions of classical models are attributed to the positive behaviour of the permittivity change on mixing for these nanofluids. The contributions to permittivity from ethylene glycol and nanoparticles are separated in two distinct terms in the variable index equation. The permittivity change on mixing calculated from this equation points out that the nanoparticles are the main responsible for the unusual permittivity increment in these colloids.