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Cascading failure is a phenomenon that minor disturbances trigger a chain reaction failure of the system, causing the disaster to quickly spread in the system and causing part or all of the system to collapse. Traditional cascading models that based on the assumption that the propagation time of cascading failures can be ignored are inadequate for modeling and analyzing all the practical cascading failure systems. It is necessary to develop a general methodology for the cascading failure systems with cascading failure propagation speed and different load effects. This paper derives new models which extend the load effect mode and consider the propagation speed of cascading failure. In the models, the time of the cascading failure propagation is considered. Three load effect modes are proposed that consider the number of remaining working components, the influence range of the failed parts, and the distance between the failed parts and the unfailed components. Additionally, the reliability of the systems with different types of cascading failures is analyzed, and formulas computing reliability indexes are derived. Numerical examples are provided to demonstrate the application of the proposed methodology. [ABSTRACT FROM AUTHOR]

While air safety issues caused by indoor decoration have received extensive attention, real-time monitoring of toxic gases is still a severe technical challenge. Therefore, a xylene and formaldehyde dual gas sensor with easy operation and high stability is proposed in this study. Herein, a NiO–MXene heterostructure was constructed by recombining NiO nanoparticles with a two dimensional layered material Ti3C2Tx MXene by in situ precipitation. The results revealed that the NiO–MXene based sensors not only showed good responses to xylene at room temperature, but also showed 5.36 times higher response than that of the pure NiO based sensor to 100 ppm formaldehyde at 170 °C. It also showed good repeatability and long-term stability. The formation of a hybrid heterojunction by single-layered MXene nanosheets combined with a p-type semiconductor NiO is an essential factor for the enhanced gas sensing performance. This work is of significance for the preparation of dual or multiple gas sensors, and has an application potential in ensuring the safety of the indoor environment. [ABSTRACT FROM AUTHOR]

Activation of low-grade phosphate rocks such as dolomite phosphate rock (DPR) with organic molecules of humic acid (HA) and sodium lignosulfonate (SLS) holds promise for developing slow release P fertilizers. Consequently, activated DPR fertilizers also contains multiple essential plant elements, including P, Ca, Mg, Zn, and Fe, while minimizing leaching losses of nutrients and heavy metals. Greenhouse experiments were conducted to examine the availability of Ca, Mg, and trace metals in soils applied with activated DPR fertilizers and subsequent response of lettuce (Lactuca Sativa L.) as compared with original DPR and water-soluble P fertilizers including superphosphates (SP) and diammonium phosphates (DAP). Application of activated DPR fertilizers stimulated the uptake of Ca, Mg, Zn, Fe, B by lettuce plants relative to original DPR and DAP. Potential toxic elements such as Cr, Cd, Ni, Pb, and Cu were mostly immobilized in soil without uptake by lettuce when applied with activated DPRs primarily due to increased soil pH, as compared with water soluble fertilizers such as DAP and SPs. Apparently, the activated DPR fertilizers offer advantages over original DPR materials and water-soluble P fertilizers in providing multiple nutrients with minimal adverse effects on soil and environmental quality. [ABSTRACT FROM AUTHOR]