Zeyuan Guo

The rapid pace of urbanization has led to severe urban problems, with urban renewal emerging as an effective strategy to mitigate them. The City Betterment and Ecological Restoration (CBER) pilot scheme was an experimental policy aimed at urban renewal. Based on an optimized propensity score matching difference-in-differences model, the impact of the CBER pilot scheme on urban disease was examined. The results were threefold. (1) The CBER pilot scheme significantly alleviated urban disease in pilot cities. (2) The impact of the CBER pilot scheme was more pronounced in eastern and central regions of China, as well as in cities with high economic development, robust government capacity and abundant human resource. (3) Industrial structure optimization, infrastructure development and consumption upgrading were all effective pathways for mitigating urban disease through urban renewal. The findings offer valuable insights for other countries and regions to address urban problems and advance urbanization.

A novel structural wall pipe, PVC axial hollow‐wall pipe (AHWP) has been developed to reduce carbon emissions during the “Full Life Cycle” of PVC pipelines by reducing material use in the pipe walls. The advantages and application prospects of AHWP are examined, followed by manufacturing prototypes using advanced production techniques. The material properties, internal and external pressure resistance, impact resistance, and buried load deformation of three types of AHWP were evaluated. Experimental and numerical simulations analyzed how the cross‐sectional structure on the mechanical performance of AHWP and proposed optimization pathways. Results indicate that the production process for AHWP closely resembles that of PVC solid‐wall pipes (SWP), allowing rapid large‐scale industrial production with appropriate adjustments. Material consumption for AHWP is only 60% to 70% of that for SWP. All three types of AHWP can withstand long‐term hydrostatic pressure of 0.6 MPa, meeting the basic mechanical performance requirements for low‐pressure and non‐pressure plastic drainage pipes, with circular‐hole AHWP demonstrating the best performance. The application of AHWP can diversify the drainage pipe market, and support the societal shift toward sustainable development, characterized by the conservation of resources and the reduction of greenhouse gas emissions. Highlights: Validated new AHWP design for enhanced structural efficiency. Optimized AHWP for mechanical performance, cost, and energy. Developed and refined AHWP prototypes with manufacturing analyses. Established future structural improvement routes with testing. Demonstrated AHWP's potential in efficiency, materials, and applications.

With the increasing demand for automation in agriculture, more and more researchers are exploring the application of digital twin in agricultural production. However, existing studies have predominantly focused on enhancing resource utilization efficiency and improving irrigation control systems in agricultural production through the implementation of digital twins. Unfortunately, there is a noticeable research gap when it comes to applying digital twins specifically to buried water conveyance pipelines within an agricultural irrigation infrastructure. Focusing on the long-term performance requirements of buried pipelines in agricultural irrigation and drainage, this study established a digital twin system for the industry of axial hollow-wall pipes with an outer diameter of 200 mm, specifically designed for this field of operation. The system was used to optimize the end-forming process of axial hollow-wall pipes, resulting in improved leak tightness under internal pressure and angular deflection of the pipes. The study suggests that the most effective method for the end-forming process of axial hollow-wall pipes is to heat the pipe for 60 s at the ambient temperature of 15 °C, with heating temperatures of 225 °C on both the inner and outer sides. Additionally, preheating the stamping equipment to 70 °C and controlling the cooling temperature, during pipe detachment, to between 35 °C and 45 °C is recommended. In terms of the leak tightness under internal pressure and angular deviation, the study found that increasing the thickness of the protruding end of the sealing ring to 16 mm, and shortening the chamfer length to 20 mm, while maintaining the same slope, can enhance the sealing effectiveness of the pipeline interface. The implementation of the digital twin system improves the production efficiency of the hollow pipe production line during the end-forming process, resulting in a yield rate of the pipe of up to 95% for qualified products. Moreover, the system provides intelligent closed-loop feedback which ensures the long-term operation and maintenance of the pipelines, making it easier to identify problems and implement design improvements. By doing so, it contributes to ensuring the long-term stability of related agricultural production.