Zinc-tin oxide (ZTO) nanostructures appear as one of the most promising material systems for a new generation of nanodevices. In this work, a microwave-assisted hydrothermal synthesis to produce different shapes of Zn2SnO4 nanostructures (nanoparticles, octahedrons and nanoplates) is presented. Reproducible and homogeneous results were obtained with the advantage of reducing up to 20 h the synthesis time when compared to using a conventional oven. Furthermore, the photocatalytic activity of the Zn2SnO4 nanostructures in the degradation of rhodamine B under UV light was studied. Zn2SnO4 nanoparticles demonstrated better performance with >90% of degradation being achieved in 2.5 h.

The so called “crowd work” is an employment form that uses a digital platform to enable organisations or individuals to access other organisations or individuals to solve specific problems or to provide specific services in exchange for payment (Valenduc and Vendramin, 2016). There are many alternative terms for crowd work used in European member states, such as crowd sourcing, crowd employment, sharing economy, platform economy, gig economy, on-demand economy, collaborative economy, Peer-to-peer economy, among others (Eurofound 2018). Recently, the term “digital platform work” has developed recently to be dominant in the literature to refer to sectors where this technology has arrived. Accordingly, this report will proceed using the latter term. These forms of online intermediation have expanded from creative and high-skilled professional activities that became virtualised as a result of digitalisation to a variety of other services and activities, traditionally delivered by self-employed, that involve the maintenance or repair of material commodities or the delivery of services in person, such as cleaning, gardening, household maintenance and transport (Huws, 2017). As a result of this, workers profiles vary from highly skilled IT and creative professionals to very unskilled workers. It has been also noted that many digital platform workers are young people looking for extra income such as students, unemployed or carers (Valenduc and Vendramin, 2016). The main Portuguese reference about work in digital platforms is fused with the Uber app. Its controversial arrival in 2014 triggered fierce responses from several groups. The main legislative reference on digital platform work is the ‘Uber law’. The symbolism of the app expressed as ‘Uberization’ became synonymous of the ‘new’ precariat, seen as a hassle of technology and an attack to organized labour in the country. There are also regulations for Airbnb at state, regional and municipal level intended to limit the number of lodgings in certain areas where touristic activities are very intense. In general, the other platforms are not covered by specific regulations.

The growing use of wearable devices has been stimulating research efforts in the development of energy harvesters as more portable and practical energy sources alternatives. The field of piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs), especially employing zinc oxide (ZnO) nanowires (NWs), has greatly flourished in recent years. Despite its modest piezoelectric coefficient, ZnO is very attractive due to its sustainable raw materials and the facility to obtain distinct morphologies, which increases its multifunctionality. The integration of ZnO nanostructures into polymeric matrices to overcome their fragility has already been proven to be fruitful, nevertheless, their concentration in the composite should be optimized to maximize the harvesters' output, an aspect that has not been properly addressed. This work studies a composite with variable concentrations of ZnO nanorods (NRs), grown by microwave radiation assisted hydrothermal synthesis, and polydimethylsiloxane (PDMS). With a 25 wt % ZnO NRs concentration in a composite that was further micro-structured through laser engraving for output enhancement, a nanogenerator (NG) was fabricated with an output of 6 V at a pushing force of 2.3 N. The energy generated by the NG could be stored and later employed to power small electronic devices, ultimately illustrating its potential as an energy harvesting device.

Material, Culture, Scientific Culture: Industrial Heritage for the Future

In this article, characterization of fully patterned zinc-tin oxide (ZTO)-based memristive devices with feature sizes as small as 25 µm2 is presented. The devices are patterned via lift-off with a platinum bottom contact and a gold-titanium top contact. An on/off ratio of more than two orders of magnitude is obtained without the need for electroforming processes. Set operation is a current controlled process, whereas the reset is voltage dependent. The temperature dependency of the electrical characteristics reveals a bulk-dominated conduction mechanism for high resistance states. However, the charge transport at low resistance state is consistent with Schottky emission. Synaptic properties such as potentiation and depression cycles, with progressive increases and decreases in the conductance value under 50 successive pulses, are shown. This validates the potential use of ZTO memristive devices for a sustainable and energy-efficient brain-inspired deep neural network computation.

This report is the 3rd and final report elaborated for the project CrowdWork by the Portuguese team. The text provides the context in which digital platforms operate, as well as the main governmental initiatives in some of the sectors. Five case studies provide a description of each sector and an analysis of the existing / emerging collective
organisations, their promotors, rationale and extension. In the last chapter, the text presents our main conclusions and recommendations for policy making.

For most teachers, the use of games is not a common practice. This limited professional experience forces the teacher to reflect on the use of games, on how to integrate them into class work, and on how to enhance the development of learning based on them. Our objective is to analyse a set of game scenarios and study aspects that characterise each of them, relating these characteristics to aspects of the professional knowledge to teach with technology. The study adopts an interpretative and qualitative methodology that seeks to understand the relationship between teachers' choices and their professional knowledge. The main findings suggest that the different characteristics of the game scenarios imply the creation of different working environments in the classroom; enhance the emergence of different student difficulties, requiring different ways to support their work; allowing/promoting different conceptual approaches; and the work with different representations. These differences between the game scenarios point to different emphases on the teaching and learning knowledge and the chemistry knowledge, suggesting different mobilizations of the teacher's professional knowledge.

The potential of technology for teaching and learning mathematics has been widely recognized. However, research has shown that the integration of technology into teaching practice has proved to be difficult, with teachers' knowledge and professional development being identified as a determinant factor. Although there tends to be a focus on the teacher's knowledge of technology, the literature suggests that attention needs to be given to how to integrate technology into teaching practice, thereby involving other types of knowledge. This awareness has led several authors, inspired by Shulman's work, to develop models or conceptualizations of the knowledge required for effective integration of technology.
This study is based on a literature review of the research conducted on the models TPACK - Technological Pedagogical and Content Knowledge, KTMT - Knowledge for Teaching Mathematics with Technology, and PTK/MPTK - Mathematical Pedagogical Technology Knowledge and aims to carry out an analysis of the similarities and differences between the models considered. The main conclusions reached suggest the existence of a common basis for the models considered, but also point to several differences between them, with some highlighting the role of technology and its impact on the teaching and learning process, while others aim to integrate into the model elements based on research on technology or theories related to technology integration, such as instrumental genesis.

Abstract This paper analyses the performance of the experimental setups to assess the punching strength of slab-column connections in continuous flat slabs under vertical and horizontal loading. In the last years, several experimental campaigns have been performed to investigate the punching strength of slab-column connections, but most of the experimental tests concerned isolated slab-column connections. Among the few setups aimed at reproducing the eccentric punching failure in continuous flat slabs, the setup developed at the NOVA School of Science and Technology in Lisbon is considered in this paper. The performance of the Lisbon setup is assessed through nonlinear finite element analyses, calibrated on experimental data, by comparison with numerical results of a theoretical continuous setup. Then, the performance of the isolated setups, used in many researches and at the base of some international codes, is also evaluated through the same finite element model. Numerical analyses highlight that the setup developed in Lisbon could provide reliable ultimate rotations of continuous flat slab connections, but it underestimates the punching strength. Despite isolated setups lead to similar results when compared with the Lisbon setup, the latter seems to provide a better representation of a continuous slab-column connection. The numerical analyses presented in this paper have been performed assuming monotonic lateral loading.

n/a

Research has highlighted the potential of technology to transform the teaching of Mathematics, but also the relevance of teachers and their professional knowledge. In this article, a qualitative methodology is adopted and two episodes of the practice of one teacher are analyzed in the scope of the study of functions in the 10th grade, based on the model of Knowledge for Teaching Mathematics with Technology (KTMT). The goal is to characterize the teacher's knowledge from her practice, simultaneously understanding how this contributes to promoting the development of the teacher's knowledge. The conclusions reached show the importance of including in the KTMT conception aspects highlighted by the research on technology integration. These aspects are determinant to characterize the teacher's knowledge. They also show the relevance of the practice for the development of the teacher's knowledge and the dynamic character of the vision of knowledge offered by KTMT.

A large, well-preserved vertebrate coprolite was found in a lacustrine sediment in the Malmros Klint Formation of the Late Triassic Fleming Fjord Group in the Jameson Land Basin, central East Greenland. The size and internal and external morphology of the coprolite is consistent with that of crocodilian coprolites and one end of the coprolite exhibits evidence of post-egestion trampling. As the associated vertebrate fauna of the Fleming Fjord Group contains abundant remains of pseudosuchian phytosaurs, the coprolite is interpreted as being from a large phytosaur.

This paper presents part of a study that aimed to make more explicit the pragmatic theories that inform the design of professional development programs with an emphasis on the integration of digital technologies in the practices of mathematics teachers. The analysis carried out was based on a set of projects considered representative and implemented in four countries – Colombia, Italy, Mexico and Portugal. Based on this analysis, we identify relevant elements (e.g., similarities and differences, barriers and opportunities) and develop recommendations to be taken into account in the design of future professional development programs. In this process, we identified a set of aspects and sub-aspects, as well as several interconnections between them, which emerged in relation to five main themes and allowed us to reveal our pragmatic theories. Thus, this work provides a framework to support the design of future projects for the professional development of mathematics teachers regarding the use of digital technology.