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[Objective] Copper has a wide range of applications in new energy vehicles, electric power, communication, and other fields, and is a key metal that cannot be replaced in the process of energy transformation. China is the world’s largest copper consumer and demand country, and its industrial chain and supply chain security issues are increasingly prominent, therefore it is important to scientifically evaluate the resilience of its copper resources industrial chain and supply chain. [Methods] This study constructed a comprehensive evaluation indicator system for the resilience of China’s copper resources industrial chain and supply chain from four dimensions of resilience: resistance, recovery capacity, reorganization capacity, and renewal capacity, combined with the characteristics of the copper resources industry. The independence-adjusted entropy weight method was used to evaluate the resilience of the copper resources industrial chain and supply chain from 2000 to 2021, and the indicator barrier degree model and indicator contribution degree model were applied to identify the main factors that affect the improvement of resilience. [Results] The study found that: (1) From 2000 to 2021, the resilience of China’s copper resources industrial chain and supply chain showed a fluctuating upward trend, which was more rapid after 2012; (2) The lack of resistance was the main factor that led to the slow improvement of resilience, while the improvement of renewal capacity and recovery capacity was the main path to improving the overall resilience; (3) The coordination degree of resistance, recovery capacity, reorganization capacity, and renewal capacity fluctuated and increased after 2010, which contributed to the above-average resilience of the industrial chain and supply chain. [Conclusion] China should continue to improve the level of renewal capacity and recovery capacity of the copper resources industry, facilitate the integration of industry, academia, and research, and accelerate the transformation of scientific research results; reduce the negative impact of lack of resistance, identify the risks of chain breakage, strengthen the assessment and early warning of risks, and improve the secondary recovery rate of copper resources; collaborate in all aspects of the industrial chain and talent chain, and inject green kinetic energy into the industrial chain and supply chain.

The large amount of construction waste produced by the construction industry brings severe natural resource consumption and environmental pollution, elevating the awareness of sustainable development. Recycled aggregate concrete, crushed from construction waste, is recognized as an eco-friendly material and the current optimal solution for the environmental problem. The interface shear failure between substrate recycled coarse aggregate concrete (RAC) and overlay natural aggregate concrete becomes vital for structural safety. In order to study the direct shear performance, a total of 19 specimens were designed to carry out the direct shear test with different replacement ratios, interface types and curing ages. The whole process and failure mode were recorded. The relationships between the shear capacity and deformation, ductility, damage evolution, and energy dissipation were evaluated and discussed. The results demonstrate that the RAC component in the interface was the weak line in the shear plane, accelerating the damage evolution. In the early curing stage, the replacement ratio had a slight influence on the shear properties. Increasing the recycled aggregate replacement ratio from 0 to 100% improved the normalized strength ratio by 8.94% and 14.62%, respectively, for curing ages of 3 days and 7 days. A regression equation was proposed to predict the shear strength, accounting for the curing ages. With the increase in the replacement ratio, the ductility and energy dissipation gradually enhanced. [ABSTRACT FROM AUTHOR]

Designing the public safety and health system in the context of epidemic is critical to public safety. This paper conducts modeling and analysis on the basis of the SIR model, establishes the “big prevention” system and the “grassroots” grid system. The purpose is to improve the response speed of the public safety and health system respectively, and play a reverse detection role on the epidemic data reported by the grassroots and reduce the possibility of under-reporting. The big data and computer network are used in the public safety and health system, which is the main tool of information transmission and analysis of the public safety and health system. Finally, the feasibility of the design is demonstrated by a case study.

For marine and coastal engineering, construction resources have become scarce due to a limited local supply. Sea sand geopolymer-based recycled concrete (SSGRC) is an innovative cementitious material known for its eco-friendly benefits and corrosion resistance. This study explores the mechanical properties of SSGRC. The influences of the replacement rate of mineral slag, alkali activator concentrations, fine aggregate types, and curing ages on the compression strength of SSGRC were studied. The failure mechanism was analyzed using the failure patterns and compressive stress–strain curves. The results show that sea sand had a positive effect on geopolymer-based material. The SSGRC reached peak strength with an alkali activator concentration of 10 mol/L and a mineral slag replacement rate of 60%. The maximum stress and strain increased with an increasing curing age. The ratios of strength to the peak value were 55% and 85% after 1 day and 7 days, respectively. Using SEM, in the last hydration stage, the C-(A)-S-H gel was formed with a dense microstructure, and the geopolymer exhibited a favorable bonding performance. The constitutive models describing the complete stress–strain relationship under compression were developed. [ABSTRACT FROM AUTHOR]