52 research outputs found
ATHENA Research Book, Volume 2
ATHENA European University is an association of nine higher education institutions with the mission of promoting excellence in research and innovation by enabling international cooperation. The acronym ATHENA stands for Association of Advanced Technologies in Higher Education. Partner institutions are from France, Germany, Greece, Italy, Lithuania, Portugal and Slovenia: University of Orléans, University of Siegen, Hellenic Mediterranean University, Niccolò Cusano University, Vilnius Gediminas Technical University, Polytechnic Institute of Porto and University of Maribor. In 2022, two institutions joined the alliance: the Maria Curie-Skłodowska University from Poland and the University of Vigo from Spain. Also in 2022, an institution from Austria joined the alliance as an associate member: Carinthia University of Applied Sciences. This research book presents a selection of the research activities of ATHENA University's partners. It contains an overview of the research activities of individual members, a selection of the most important bibliographic works of members, peer-reviewed student theses, a descriptive list of ATHENA lectures and reports from individual working sections of the ATHENA project. The ATHENA Research Book provides a platform that encourages collaborative and interdisciplinary research projects by advanced and early career researchers
Challenges for engineering students working with authentic complex problems
Engineers are important participants in solving societal, environmental and technical problems. However, due to an increasing complexity in relation to these problems new interdisciplinary competences are needed in engineering. Instead of students working with monodisciplinary problems, a situation where students work with authentic complex problems in interdisciplinary teams together with a company may scaffold development of new competences. The question is: What are the challenges for students structuring the work on authentic interdisciplinary problems? This study explores a three-day event where 7 students from Aalborg University (AAU) from four different faculties and one student from University College North Denmark (UCN), (6th-10th semester), worked in two groups at a large Danish company, solving authentic complex problems. The event was structured as a Hackathon where the students for three days worked with problem identification, problem analysis and finalizing with a pitch competition presenting their findings. During the event the students had workshops to support the work and they had the opportunity to use employees from the company as facilitators. It was an extracurricular activity during the summer holiday season. The methodology used for data collection was qualitative both in terms of observations and participants’ reflection reports. The students were observed during the whole event. Findings from this part of a larger study indicated, that students experience inability to transfer and transform project competences from their previous disciplinary experiences to an interdisciplinary setting
Polymer Dynamics In Disordered Nanoparticle Packings: Effect Of Confinement, Interfaces, And Humidity
Infiltration of polymers into disordered nanoparticle packings has shown to be a powerful method of fabricating highly loaded nanocomposites with superb mechanical properties. Polymer-infiltrated nanoparticle packings provide a unique platform to study the dynamics of macromolecules under extreme nanoconfinement. The degree of confinement can be tuned by appropriate choice of particle size and polymer molecular weight. The presence of large interfacial area between the polymer and the particle, high degree of nanoconfinement, and environmental triggers like atmospheric humidity can impact the dynamics of polymers at the segmental and the chain level. By using tools like microscopy, ellipsometry and molecular dynamic simulations, we investigate the dynamics of polymers at unprecedented levels of confinement. In solvent-driven infiltration of polymers (SIP) system, polymer chains are plasticized by capillary condensed solvent leading to capillary motion of the solvated polymer into the pores of the nanoparticle packing. We detail our investigations on the mechanism of infiltration with increasing polymer-nanoparticle interactions. In capillary rise infiltration(CaRI), the polymer film-nanoparticle packing bilayer is annealed above the glass transition temperature of the polymer leading to the polymer wicking into the pores of the packing. The dynamics of rise of the polymer into the nanoparticle packing can be studied by ellipsometric front-tracking giving a measure of the chain dynamics of polymer – effective viscosity – based on the Lucas-Washburn equation. Our investigations into the dynamics of high Tg, glassy polymers is complemented by studies of low Tg, mobile chains in disordered nanoparticle packings. Once infiltrated into a region of nanoparticle packings, these mobile chains spread out into adjoining unfilled regions. This room temperature, spontaneous lateral motion of polymer can be tracked to understand interfacial polymer diffusion under confinement. Higher humidity, unexpectedly, leads to faster spreading of the polymers within the packings possibly due to reduced particle-polymer friction with water coverage on particle surface. Thus, this work presents the effects of confinement, interfacial interactions, and atmospheric humidity on the chain and segmental dynamics of polymers in pores of disordered nanoparticle packings
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A hybrid piezoelectric and electrostatic energy harvester for scavenging arterial pulsations
Implantable and wearable biomedical devices suffer from a limited lifespan of on-board batteries which results in a requirement to change the battery or the device itself causing additional physical discomfort. In order to overcome this, various energy harvesters have been developed. The human body possesses several types of energy available for scavenging through appropriately designed energy harvesting devices, while cardiovascular system in particular represents a constant reliable source of mechanical energy from vibration. Most conventional energy harvesters exploit only a single phenomenon, such piezo- or triboelectricity, thus producing reduced power density. As an improvement, hybridisation of energy harvesters intends to negate this drawback by simultaneously scavenging energy by multiple harvesters.
In the present work, the reverse electrowetting on dielectric (REWOD) phenomenon is combined with the piezoelectric effect in a proof-of-concept hybrid harvester for scavenging biomechanical energy from arterial or other type pulsations. A mathematical model of the harvester was developed, and a computational investigation using CFD, and fluid-structure interaction simulations were carried out using the COMSOL Multiphysics software. The effect of the materials of piezoelectric film and geometrical features of the harvester on parameters such as the displacement, the frequency of pulsations and the energy produced were studied. An experimental setup that could imitate the displacements caused from arterial pulsations was designed and the produced electrical energy characteristics were analysed. A comparison between experimental and computational data was carried out and demonstrated a good agreement. Dependencies between geometrical parameters and electrical output were obtained, recommendation on piezoelectric materials and design solutions were provided
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