The effect of isocyanate trimer on the flame retardancy mechanism of polyisocyanurate (PIR) foam was studied in three aspects, including the mechanism of thermal decomposition in the condensed phase, the barrier mechanism of carbon layer formation on the surface in the condensed phase, and the mechanism in the gaseous phase, by using infrared spectroscopy, scanning electron microscopy, thermal analysis, a cone calorimeter, and high-temperature pyrolysis gas chromatography mass spectrometry. The results show that the trimmer can improve the thermal stability of the PIR foam and is not easily decomposed in the combustion. The trimmer can increase the carbon content of the PIR foam to 29.9% of that of the polyurethane (PU) foam. The carbon layer formed is denser, and it can retard heat and oxygen and thus improve the flame retardant properties; trimer can reduce the release of flammable polyol gas, decompose into more carbon dioxide, which is an inert gas, and it has certain flame retardant effects in the gaseous phase.
This work investigates epoxy composites reinforced by randomly oriented, short glass fibres and silica microparticles. A full-factorial experiment evaluates the effects of glass fibre mass fraction (15 wt% and 20 wt%) and length (5 mm and 10 mm), and the mass fraction of silica microparticles (5 wt% and 10 wt%) on the apparent density and porosity, as well as the compressive and tensile strength and modulus of the hybrid composites. Hybrid epoxy composites present significantly higher tensile strength (9%) and modulus (57%), as well as compressive strength (up to 15%) relative to pure epoxy.
The melon culture is one of the Brazilian horticultural crops, due to its productive potential and socio-economic role. It is recommended for the State of Goiás and the Federal District for it is easy to plant and having need of zoning of climatic conditions and thus, being able to perform their sowing. The present work used the Sarazon program to perform the water balance of the melon crop, for the 2nd, 4th and 6th five-day sowing dates in August, September and October and in relation to the water reserves in the soil of 50 mm and 75 mm. The data were spatialized using the SPRING 4.3 program. It was observed that the producers are performing in practice what can be demonstrated in theory that the period October 16–20 is the most indicated for sowing in soils of 50 mm of water reserve and October 6–10 the beginning of sowing in soil of 75 mm of water reserve for the cultivation of melon and have adequate profitability.
Several studies have discussed the benefits of blockchain in human resources management (HRM) policies to support the efficiency of HRM routine practices in organizations. The discussion ranges from selection and recruitment to employee separation. With the growing interest in digital application usage, research focused on utilization and effective measurement is needed. However, the existing literature review on blockchain-based HRM practices linked to cost efficiency still needs to be improved. Hence, this study aims to review current studies on blockchain human resources management systematically. This study investigates the trends in blockchain application usage in terms of practices, methodologies, and settings. This study used a literature survey and Publish or Perish software with Google Scholar and Scopus as the databases. 123 articles published in 19 journals from 2010 to 2022 were selected. This study used systematic data to reveal trends in HRM practices and qualitative inductive analysis to define relevant themes within the topic. The results show that blockchain applications for efficiency are used mainly in the recruitment and selection process, ranging from personal data verification to the quality of decision-making in skill development and maintenance. Five HRM practices have been discussed, indicating potential explorative and exploitative future research to improve the effectiveness of using blockchain in HRM practices.
This study adopts a discursive and analytical perspective to explore how technological advances are reconfiguring the dynamics of the global labour market, with special attention to the phenomenon of microwork. Microwork, characterised by short, fragmented tasks carried out through digital platforms and geographically distributed, has seen exponential growth, particularly in nations with lower economic development. This type of work shows a growing distinction between tasks of a complex and creative nature and those of a repetitive and monotonous nature that do not require advanced skills to perform. This differentiation can intensify wage disparities between developed and developing countries, as well as contribute to the precariousness of work in activities considered less complex and valued. The article highlights the emergence of unstable and poorly paid jobs that do not require specific qualifications and discusses their impact on social security systems in countries where labour regulations are insufficient. Using a theoretical-methodological approach, the research examines the role of artificial intelligence in the rise of micro-labour and its socio-economic implications. It concludes that despite the flexibility and short-term earning opportunities offered by microwork, it poses considerable challenges in terms of income security, workers’ rights, and social protection, emphasising the need for regulatory measures to mitigate its adverse effects on vulnerable communities.
Tourism stands as a cornerstone industry, experiencing continual expansion within the global economy, and is increasingly acknowledged for its crucial role as an economic catalyst. The convergence of the tourism sector with the film culture industry amplifies the economic advantages of regions and enriches cultural narratives while bolstering the international resonance of regional brands. This study examines the promotional efficacy of adapted films in fostering the development of local tourism sectors. It investigates the impact of adapted films on the development of local tourism economy and provides a new analytical perspective to describe their specific contribution to the tourism economy. Empirical findings underscore that adapted films imbued with regional nuances substantially augment local tourism revenue, catalyzing the growth of the tourism sector. This highlights the capacity of adapted films to amplify regional exposure, nurturing the expansion of the local tourism economy. The findings of the study reveal that the promotional impact of adapted films on local tourism sectors is more pronounced in less developed regions than in more developed regions. Moreover, areas with limited transportation infrastructure witness a heightened promotional effect from the film industry. Rigorous robustness and endogeneity tests corroborate the reliability of these findings.
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