Suchergebnisse

Air travel has been one of the hardest hit industries of COVID-19, with many flight cancellations and airport closures as a consequence. By analysing structural characteristics of the Official Aviation Guide flight data, we show that this resulted in an increased average distance between airports, and in an increased number of long-range routes. Based on our study of network robustness, we uncover that this disruption is consistent with the impact of a mixture of targeted and random global attack on the worldwide air transportation network. By considering the individual functional evolution of airports, we identify anomalous airports with high centrality but low degree, which further enables us to reveal the underlying transitions among airport-specific representations in terms of both geographical and geopolitical factors. During the evolution of the air transportation network, we also observe how the network attempted to cope by shifting centralities between different airports around the world. Since these shifts are not aligned with optimal strategies for minimizing delays and disconnects, we conclude that they are consistent with politics trumping science from the viewpoint of epidemic containment and transport.

This study dedicated to a novel method for synthesizing silicon-carbon (Si/C) and silicon dioxide-carbon (SiO2/C) nanocomposite anodes for lithium-ion batteries, utilizing industrial copper slags from the Almalyk Mining and Metallurgical Complex as a cost-effective source of SiO2. The synthesized nanocomposites address key challenges in lithium-ion battery anodes, including the volumetric expansion of silicon and its low conductivity, by leveraging the high lithiation capacity of silicon combined with the structural stability and conductivity of carbon. Amorphous SiO3 was extracted from copper slags via ammonium fluoride (NH4F) treatment and subsequently reduced to metallurgical-grade silicon through carbothermal reduction. The resulting SiO2/C and Si/C composites were thoroughly characterized using SEM, XRD, and electrochemical analyses, demonstrating improved electrochemical performance, favorable particle size distribution, and stability. This approach not only reduces material costs but also promotes environmental sustainability by repurposing industrial waste, offering promising candidates for high-performance lithium-ion battery anodes.