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Article  |  2021-07-01

Sustainable Practice in Pavement Engineering through Value-Added Collective Recycling of Waste Plastic and Waste Tyre Rubber

Waste plastics, such as waste polyethylene terephthalate (PET) beverage bottles and waste rubber tyres are major municipal solid wastes, which may lead to various environmental problems if they are not appropriately recycled. In this study, the feasibility of collectively recycling the two types of waste into performance-increasing modifiers for asphalt pavements was analyzed. This study aimed to investigate the recycling mechanisms of waste PET-derived additives under the treatment of two amines, triethylenetetramine (TETA) and ethanolamine (EA), and characterize the performances of these additives in modifying rubberized bitumen, a bitumen modified by waste tyre rubber. To this end, infrared spectroscopy and thermal analyses were carried out on the two PET-derived additives (PET–TETA and PET– EA). In addition, infrared spectroscopy, viscosity, dynamic shear rheology, and multiple stress creep recovery tests were performed on the rubberized bitumen samples modified by the two PET-derived additives. We concluded that waste PET can be chemically upcycled into functional additives, which can increase the overall performance of the rubberized bitumen. The recycling method developed in this study not only helps alleviate the landfilling problems of both waste PET plastic and scrap tyres, but also turns these wastes into value-added new materials for building durable pavements.

Xiong Xu ,   Zhen Leng   et al.

Review  |  2021-07-01

The State-of-the-Art Review on Applications of Intrusive Sensing, Image Processing Techniques, and Machine Learning Methods in Pavement Monitoring and Analysis

In modern transportation, pavement is one of the most important civil infrastructures for the movement of vehicles and pedestrians. Pavement service quality and service life are of great importance for civil engineers as they directly affect the regular service for the users. Therefore, monitoring the health status of pavement before irreversible damage occurs is essential for timely maintenance, which in turn ensures public transportation safety. Many pavement damages can be detected and analyzed by monitoring the structure dynamic responses and evaluating road surface conditions. Advanced technologies can be employed for the collection and analysis of such data, including various intrusive sensing techniques, image processing techniques, and machine learning methods. This review summarizes the state-of-the-art of these three technologies in pavement engineering in recent years and suggests possible developments for future pavement monitoring and analysis based on these approaches.

Yue Hou ,   Qiuhan Li   et al.

Article  |  2021-07-29

Development Strategy of Space Internet Constellation System in China

The space Internet constellation system is an important component of China’s space information infrastructure and has become a focus of international competition in future. However, China is still in the preparatory stage of the space Internet constellation system construction. We started late and are faced with many risks such as a backward space resource position, lack of independent standards, a weak foundation for technological development, limitation in traditional application fields, and uncontrollability of network security; therefore, China’s space Internet constellation system is still far from supporting rapid economic and social development. Facing the opportunities and challenges, we overview the space Internet constellation system development in China and analyze the macro demand for space Internet construction. Subsequently, we analyze the development trend of the system both in China and abroad and propose the development ideas, key tasks, and technical routes of the space Internet constellation system construction in China. To improve the service abilities of China’s space information network and establish a flexible space system, we suggest that China should strengthen top-level planning at the national level in the design and engineering construction stages, accelerate the exploitation of space and frequency resources, formulate satellite Internet standards, intensify efforts to tackle key technologies, promote integrated and innovative applications, and build a network security and protection system.

Li Feng ,   Yu Hang   et al.

Article  |  2021-07-28

Overview of the Global Crop Seed Industry and Strategic Thinking on its Development in China

The seed industry is a basic and core industry that is strategically important for a nation. Considering the national guidance opinions on fields such as seeds and cultivated land, industrialization of biological breeding, and development of core technologies for germplasm resources, the seed industry has become a driving force for the rapid development of China’s agriculture. In this study, we summarize the current status of the global crop seed industry from the aspects of germplasm resources protection and utilization, biological breeding technology development, seed industry development, etc. Moreover, we analyze the problems of China’s seed industry from an international perspective. To promote the development of the seed industry, China should implement a national germplasm resources strategy to consolidate the foundation of its seed industry; implement a scientific and technological innovation strategy in the seed industry to achieve breakthroughs in original innovation; construct a seed industry system with Chinese characteristics to enhance industrial competitiveness; promote the role of enterprises in technological innovation; and modernize the supervision system to improve industrial advantages.

Zheng Huaiguo ,   Zhao Jingjuan   et al.

Article  |  2021-07-28

Development Strategy of Intelligent Logistics for Agricultural Products

The lagging informatization and intellectualization of the agricultural product postharvest supply chain is the main factor that results in low circulation efficiency and serious quality loss. Improvement on the postharvest added values of agricultural products necessitates the planning of intelligent logistics for agricultural products in China. In this study, we analyze the demand for intelligent logistics of agricultural products, summarize the development status, and investigate the problems existing in informatization, standards and quality, and professionals. Considering China’s conditions, we propose the development goals and key tasks of the intelligent logistics for agricultural products in China by 2035. The study shows that strengthening policy support, improving the standardization system, and promoting personnel training are the foundation for the intelligent logistics of agricultural product. The continuous innovation and extended application of the new-generation information technology has promoted the transformation and upgrading of traditional agricultural logistics toward intelligent agricultural logistics in China. In the future, an intelligent, integrated, and green supply chain will be the major development direction for intelligent agricultural logistics. This study can provide a basic reference for improving overall operation efficiency and upgrading service quality of the agricultural logistics industry.

Han Jiawei ,   Li Jiacheng   et al.

Article  |  2021-07-27

Development Status and Future Prospects of Hydrogen Fuel Cell Technology

Hydrogen fuel cell is a key element for conversing hydrogen energy into electric power and has attracted increasing attention from the aspects of basic research and industrial application following the proposal of carbon neutral and carbon peaking. Focusing mainly on the hydrogen fuel cell technology system, we analyze the research progress and development trends of membrane electrode components (such as proton exchange membranes, electrocatalysts, and gas diffusion layers), bipolar plates, system components, and control strategies. Subsequently, we propose the development directions of the hydrogen fuel cell technology system by 2035, following the analysis of the development status of the hydrogen fuel cell technology in China in terms of localization rate, system lifetime, power density, and manufacturing cost. To accelerate the application of hydrogen energy and hydrogen fuel cell technology, we suggest that research on hydrogen production technology should be strengthened to reduce the cost of hydrogen fuel, the technological research and application of key materials and core components should be accelerated, and industrial plans with increased investment should be formulated to establish a complete policy support system.

Liu Yingdu ,   Guo Hongxia   et al.

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