Search

Urban rail transit usually contains many small radius curved tracks, and wheel flange wear is prominent, which greatly reduces the service life and increases the maintenance and replacement costs of wheelsets. Two metro lines in Shanghai of China had suffered from severe flange wear since 2017, and the flange wear rate increased gradually over the next three years. This paper presents the understanding and treatment of severe flange wear through field measurement and numerical simulation. The investigation results indicated that the key factors causing severe flange wear were poor rail gauge face lubrication, the use of a low conicity wheel profile for trains running on the two metro lines containing many small radius curved tracks, and the lack of timely maintenance of low rail profiles. Three countermeasures were proposed to mitigate wheel flange wear, which were evaluated through wheel–rail matching analysis and wheel wear prediction. Then, two countermeasures, i.e. improving rail gauge face lubrication and employing the LM-30 wheel profile, were verified through field tests. [ABSTRACT FROM AUTHOR]

To overcome the thermodynamic and kinetic impediments of the Sabatier CO2 methanation reaction, the process must be operated under very high temperature and pressure conditions, to obtain an industrially viable conversion, rate, and selectivity. Herein, we report that these technologically relevant performance metrics have been achieved under much milder conditions using solar rather than thermal energy, where the methanation reaction is enabled by a novel nickel‐boron nitride catalyst. In this regard, an in situ generated HOB⋅⋅⋅B surface frustrated Lewis's pair is considered responsible for the high Sabatier conversion 87.68 %, reaction rate 2.03 mol gNi−1h−1, and near 100 % selectivity, realized under ambient pressure conditions. This discovery bodes well for an opto‐chemical engineering strategy aimed at the development and implementation of a sustainable 'Solar Sabatier' methanation process. [ABSTRACT FROM AUTHOR]

Treating hazardous waste Ni from the electroplating industry is mandated world-wide, is exceptionally expensive, and carries a very high CO2 footprint. Rather than regarding Ni as a disposable waste, the chemicals and petrochemicals industries could instead consider it a huge resource. In the work described herein, we present a strategy for upcycling waste Ni from electroplating wastewater into a photothermal catalyst for converting CO2 to CO. Specifically, magnetic nanoparticles encapsulated in amine functionalized porous SiO2, is demonstrated to efficiently scavenge Ni from electroplating wastewater for utilization in photothermal CO2 catalysis. The core-shell catalyst architecture produces CO at a rate of 1.9 mol·gNi−1·h−1 (44.1 mmol·gcat−1·h−1), a selectivity close to 100%, and notable long-term stability. This strategy of upcycling metal waste into functional, catalytic materials offers a multi-pronged approach for clean and renewable energy technologies. The valorization of undesirable substrates offers a two-fold strategy for pollution remediation and renewable energy conversion. Here, authors demonstrate the scavenging of Ni from electroplating wastewater and subsequent utilization as materials for photothermal CO2 reduction. [ABSTRACT FROM AUTHOR]