Methylene blue intercalated vanadium oxide with synergistic energy storage mechanism for highly efficient aqueous zinc ion batteries

With the rise of aqueous multivalent rechargeable batteries,inorganic-organic hybrid cathodes have attracted more and more attention due to the complement of each other’s advantages.Herein,a strategy of designing hybrid cathode is adopted for high efficient aqueous zinc-ion batteries(AZIBs).Methylene blue(MB)intercalated vanadium oxide(HVO-MB)was synthesized through sol-gel and ion exchange method.Compared with other organic-inorganic intercalation cathode,not only can the MB intercalation enlarge the HVO interlayer spacing to improve ion mobility,but also provide coordination reactions with the Zn^(2+)to enhance the intrinsic electrochemical reaction kinetics of the hybrid electrode.As a key component for the cathode of AZIBs,HVO-MB contributes a specific capacity of 418 mA h g^(-1) at 0.1 A g^(-1),high rate capability(243 mA h g^(-1) at 5 A g^(-1))and extraordinary stability(88%of capacity retention after 2000cycles at a high current density of 5 A g^(-1))in 3 M Zn(CF_(3)SO_(3))_(2) aqueous electrolyte.The electrochemical kinetics reveals HVO-MB characterized with large pseudocapacitance charge storage behavior due to the fast ion migration provided by the coordination reaction and expanded interlayer distance.Furthermore,a mixed energy storage mechanism involving Zn^(2+)insertion and coordination reaction is confirmed by various ex-situ characterization.Thus,this work opens up a new path for constructing the high performance cathode of AZIBs through organic-inorganic hybridization.

Flexible Optimal Model and Algorithm for Track Utilization in High-speed Railway Stations

Track utilization is the most important technical operation in high-speed railway stations.It is an effective way to take flexible man-agement based on dispatchers’decision preferences into consideration for making track utilization plans to relieve the influence caused by unmeasurable unstructured factors.Thus,based on the flexible management concept and taking the flexible optimal for track utilization in high-speed railway stations as the object,time and space occupation safety trajectories of arrival routes,departure routes and tracks are all analysed.Then,taking the following constraints into consideration-minimum safety time intervals for var-ious routes and tracks occupation,space-time arc occupation and decision-makers’preferences-a flexible optimal model for track utilization in high-speed railway stations is established to maximize its balance and robustness and to minimize its volatility at the same time.Further,a flexible optimal solution based on a simulated annealing algorithm is designed to make a safety track utilization plan in high-speed railway stations integrating the dispatchers’decision preference.The results from the experiments show that the proposed methodology can effectively make satisfied safety track utilization plans based on decision-makers’preferences,which can improve its balance and robustness level significantly.Meanwhile,its volatility can be reduced as much as possible caused by flexible management based on artificial intervention to ensure the relative stability of the plan.

Hazard identification and risk assessment of Abuja rail mass transit

Due to multiple advantages in terms of capacity,safety,dependability and punctuality,rail mass transit plays a vital role in easing urban traffic congestion.In addition,rail mass transit is environmentally friendly.Even though it is beneficial to passengers in urban areas,security issues have become increasingly serious in recent years.To improve the safety and dependability of the rail mass transit system to some extent and limit the loss to a bare minimum,it is necessary to identify and evaluate the hazards connected with rail mass transit in the early stages of the system’s operation.Against this backdrop,this research employs a riskmatrix approach to examine the dangers connected with Abuja’s rail mass transit system(ARMT).The questionnaire is designed and delivered to 100 participants,including personnel and passengers,to get their perceptions of hazards at the ARMT.The questionnaire is the initial step in the research process.The four safety variables discussed in this study are human error,equipment design failure,environmental conditions and management.Human error is the most significant factor covered in this research.Understanding the source of risk stemming from these four safety variables at the early stages of rail mass transit operation can significantly improve the system’s overall safety and reliability,which can be paramount.According to the findings of the investigations,human-related activity is the most significant possible cause of risk at that ARMT,with a high level of risk portrayed by the data.