ABSTRACT
In order to evaluate the impact of emergencies on the resilience of highway transportation, a resilience network hierarchical model of the highway transportation system was constructed by analyzing the formation and emergence process of safety resilience in the highway transportation system. Four layers of networks were divided, including highway network, transport network, traffic network, and emergency network. Combined with the network hierarchical model, a resilience evaluation index system was designed, and an assessment method for highway transportation systems based on the fuzzy analytic hierarchy process(FAHP) was proposed. Finally, a case study of a public health emergency in a region of Hunan was carried out. The results show that the proposed method for evaluating the safety resilience of highway transportation systems can better reflect the overall resilience under public health emergencies, which is consistent with the quantitative analysis results through the system resilience curve. It helps to accurately evaluate the safety resilience of the system. At the same time, this method has the advantages of flexibility and simplicity in solving unstructured decision-making problems of the system, which helps to improve the safety production management and safety resilience level of highway transportation systems. In the future, the scope of research scenarios and regions can be expanded, and further analysis of the evolution of safety resilience and the ability of resilience development in different stages under external disturbances can be conducted in order to further explore and optimize the resilience of the system.
Subject(s)
Emergencies , Transportation , Humans , Safety , Models, Theoretical , Fuzzy LogicABSTRACT
Sludge dewatering plays a critical role in the efficient and cost-effective management of wastewater treatment plants. Ultrasonic treatment has emerged as a promising technique for improving dewatering processes. This study aims to evaluate the impact of ultrasonic treatment on sludge dewatering characteristics. A series of experiments were conducted to evaluate the dewatering characteristics of sludge under ultrasonic treatment. Experimental data was collected, and the effects of ultrasonic parameters on dewatering efficiency were analyzed. Ultrasound has the capacity to disintegrate sludge flocs, liberate tightly bound water, and enhance sludge dewatering capabilities. The application of ultrasound leads to the breakdown of sludge flocs, which facilitates a substantial amount of organic acids or carbonates. This, in turn, modifies the pH value of the sludge. Additionally, ultrasound induces instantaneous high temperature and pressure within the liquid phase, consequently elevating the temperature of the sludge slurry. Optimum ultrasound energy density and duration of ultrasound treatment exist. For the sludge samples analyzed in this investigation, it was determined that the optimal ultrasonic energy density is 9.8 W, while the optimal duration of ultrasound treatment is 30 s. Excessively escalating the sound energy density or prolonging the duration of ultrasound may yield unfavorable outcomes in terms of sludge dewatering effectiveness. To enhance sludge dewatering, it is crucial to select appropriate ultrasonic energy density and duration of ultrasonic treatment. This study demonstrates the positive impact of ultrasonic treatment on the dewatering characteristics of sludge. The findings provide valuable insights into the potential of ultrasonic technology for enhancing sludge dewatering.