Optical, stability and energy performance of water-based MXene nanofluids in hybrid PV/thermal solar systems

Solar thermal collectors have been recognized as promising devices for solar energy harvesting. The absorbing properties of the working fluid are crucial because they can significantly influence the efficiency of the solar thermal collectors. The performance of photovoltaic-thermal (PV/T) systems can be optimized by applying nanofluids as working fluids. MXene is a newly developed 2-D nanomaterial that has proven excellent potential in electrical applications with a lack of research in the thermal and optical applications. The present work extensively studied the optical potential of the water/MXene nanofluids with respect to the variation of MXene concentrations (0.0005–0.05 wt%) and types of surfactant (CTAB or SDBS) used in a hybrid PV/T system. The relationship between the investigated parameters was evaluated through an experimental correlation. The evaluation of the nanofluids in term of the transmittance was conducted through the Rayleigh method. The MXene concentrations and the types of the surfactant play predominant role in the transmittance, absorbance and dispersion stability of the water/MXene nanofluids. The corresponding effects due to these factors become the most noticeable in the wavelengths of 300–1350 nm. Low concentration of the MXene and shorter path lengths lead to higher transmittance. The application of the low concentration of water/MXene nanofluids as the optical filtration in a hybrid PV/T system yields a higher performance compared to a conventional PV/T system. Therefore, this research work provides novelty value in understanding the impacts of using water/MXene nanofluid in the hybrid PV/T solar collectors to harness additional energy

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Insights on the thermal potential of a state-of-the-art palm oil/MXene nanofluid in a circular pipe

MXene, a recently created nanomaterial, offers significant potential for thermal, electrical, and a variety of other uses. MXene was utilized to generate heat transfer nanofluids with improved thermophysical properties for thermal applications and to establish the optimal parameters for achieving the best thermal performance. In this study, a palm oil/MXene nanofluid was used as the heat transfer fluid in a circular pipe to evaluate its thermal impact at different Reynolds numbers and applied heat fluxes at a range of introduced MXene nanoparticles’ concentrations. Thermal conductivity and viscosity were shown to be linked to temperature and nanoparticle concentrations ranging from 0.01 to 0.1 mass%. The influence of concerted MXene nanoparticles (0.01 to 0.1 mass%) on the behavior of the PO/MXene nanofluid was studied using CFD simulations at various flow Reynolds numbers (2,500–5,000) and wall heat fluxes (40,000–90,000 W.m−2). The results indicate that increasing the nanoparticle concentration resulted in higher heat transfer coefficients and lower Nusselt numbers. MXene nanoparticles were more efficient at lowering the wall temperature and increasing the pace of cooling when applied at larger heat fluxes and lower Re numbers. The results reported in this article indicate that MXene nanomaterials have a strong potential for overcoming the low heat transfer difficulties encountered in heat exchange systems