Past studies showed that varying nanoparticles size could affect several properties of nanofluids. This could lead to significant change of hydro-thermal performance in various applications. In the present study, the effect of copper oxide (CuO) nanoparticle size on the viscosity of nanofluid was investigated under different working temperature and concentration. Base fluid consists of equal amount of distilled water and ethylene glycol. It was found that the addition of 0.05 vol.% CuO into base fluid caused increment of viscosity by 11.8% and 7.27%. On the other side, particle size effect was found to be insignificant on the viscosity of nanofluids at low concentration of CuO nanoparticles (0.025 vol.%). Lastly, the viscosity measured in the present study was predictable by two correlations proposed in past studies and only slight deviation was observed.

The vanadium redox flow battery (VRFB) is a highly regarded technology for large‐scale energy storage due to its outstanding features, such as scalability, efficiency, long lifespan, and site independence. This paper provides a comprehensive analysis of its performance in carbon‐based electrodes, along with a comprehensive review of the system‘s principles and mechanisms. It discusses potential applications, recent industrial involvement, and economic factors associated with VRFB technology. The study also covers the latest advancements in VRFB electrodes, including electrode surface modification and electrocatalyst materials, and highlights their effects on the VRFB system‘s performance. Additionally, the potential of two‐dimensional material MXene to enhance electrode performance is evaluated, and the author concludes that MXenes offer significant advantages for use in high‐power VRFB at a low cost. Finally, the paper reviews the challenges and future development of VRFB technology.

Coronavirus disease 2019 (COVID-19) has delayed global economic growth, which has affected the economic life globally. On the one hand, numerous elements in the environment impact the transmission of this new coronavirus. Every country in the Middle East and North Africa (MENA) area has a different population density, air quality and contaminants, and water- and land-related conditions, all of which influence coronavirus transmission. The World Health Organization (WHO) has advocated fast evaluations to guide policymakers with timely evidence to respond to the situation. This review makes four unique contributions. One, many data about the transmission of the new coronavirus in various sorts of settings to provide clear answers to the current dispute over the virus’s transmission were reviewed. Two, highlight the most significant application of machine learning to forecast and diagnose severe acute respiratory syndrome coronavirus (SARS-CoV-2). Three, our insights provide timely and accurate information along with compelling suggestions and methodical directions for investigators. Four, the present study provides decision-makers and community leaders with information on the effectiveness of environmental controls for COVID-19 dissemination. Graphical Abstract Supplementary Information The online version contains supplementary material available at 10.1007/s11356-022-23392-z.

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