Search

PurposeThe paper investigates the learning practices carried out by Higher Education Institutions (HEIs) in the transition from strictly face-to-face to remote teaching in response to the coronavirus disease 2019 (COVID-19) pandemic. It also analyses how these practices could be used as a baseline to support new perspectives on learning in the technological education field.Design/methodology/approachThe authors conducted a single-case study of a Brazilian technological university.FindingsThis study’s findings indicate that institutional planning and providing support to faculty and students were essential measures for a successful transition from face-to-face teaching to emergency remote teaching. Planning includes careful selection by the HEI of the tools that make a virtual learning environment and the strategies used to replace face-to-face teaching with emergency remote teaching. Our study points out the lessons learned during the pandemic. It presents guidelines for HEIs on how to prepare for a return to face-to-face teaching, embodying some learning dimensions such as synchronous or asynchronous, active or passive, individual or collective, and mediated or not mediated by information and communication technologies (ICTs).Originality/valueThe paper provides reflections on the four dimensions to support decisions to leverage learning in each educational institution. This paper's main contribution is that the concept of teaching and learning must be comprehensive and inclusive according to the particular HEI context.

PLA nanocomposites containing 1 wt% ZnO nanofibers have been prepared by solvent-cast 3D printing. The ZnO nanofibers were produced by electrospinning and dispersed in PLA by ultrasound. Scanning electron microscopy revealed that the fibers were dispersed throughout the nanocomposite. Surface specimen assessment by atomic force microscopy indicated the presence of nanofibers near the surface of the nanocomposite. TGA tests showed the nanocomposite had a lower thermal stability than the neat PLA, probably induced by PLA hydrolysis catalyzed by ZnO. DSC results revealed higher crystallinity in the nanocomposite, induced both by the presence of ZnO nanofibers and by the 3D printing process, though the 3D printing process showed to be more important in increasing the crystallinity. XRD results also showed a higher crystallinity for the nanocomposite. The study opens an interesting field for the development of PLA/ZnO nanocomposites using ZnO nanofibers made by electrospinning, e.g. in medical and packaging applications.

Morphological and crystallographic characteristics of HfOx with different oxygen concentrations (0 ≤ x ≤ 2.5) and thicknesses (18 nm ≤ t ≤ 310 nm) were analyzed in this work before and after thermal annealing at 700°C in N2 atmosphere for 1h. The morphology of the as-deposited, low oxygen concentration films (t = 100 nm) is formed by a well-defined granular structure with grains around 20 nm in diameter. For higher oxygen concentration, the roughness increases, as a consequence of a very porous surface morphology. At the same time, the crystallographic structure changes from HCP with a {0002} preferred orientation to an amorphous structure as oxygen concentration increases. As the thickness of the HfO2 films increases, we also observed the formation of a high surface porosity, with pore diameter ranging from 80 nm to 120 nm. The changes observed in morphology and crystallinity of the films, as we increase the concentration of contaminants, occurs because of the lowering of the adatoms surface diffusion, which prevents them from reaching lower energy points during the formation of the microstructure of the films. Furthermore, this lowered surface diffusion favors the process of grain renucleation, which leads to roughness increasing, and to an enhancement of the formation of porous surfaces. After annealing, all films exhibit the monoclinic crystallographic phase associated with HfO2. Surface morphology of the films is consistent with a polycrystalline structure with grain diameters varying between 10 nm and 200 nm. As their size increases, the grains become very faceted, a finding consistent with the improvement in film crystallinity. Our results suggest that long-time annealing promotes the diffusion of oxygen from the SiO2-Hf interface to the film, compensating any O2 deficit in the film. Formation of the monoclinic phase is also favored by the improvement in the film stoichiometry promoted by thermal treatment. Also, the critical size of the nuclei, associated with a grain growth in a particular crystallographic orientation, decreases as a consequence of the high temperature during thermal annealing. Therefore, formation of faceted grains and increasing of surface roughness are favored in thicker films.