Investigating the interconnectedness of carbon, fossil energy, and financial markets: A dynamic spillover index approach.

Against the background of the global active pursuit of carbon neutrality, this paper uses the DY spillover index method to analyze the spillover network effects between carbon, fossil energy and financial markets. The research results show that the spillover effects between these three markets change over time, with an average spillover index of 25.30%, showing a significant mutual influence. Further analysis found that the EU carbon market plays an important role in spillover effects. Especially under the influence of extreme events, the spillover effects reach their peak. At this time, the degree of mutual influence between markets is as high as 60.01%. In addition, during the COVID-19 epidemic, the spillover effect of the EU carbon market on other markets also reached its maximum, indicating that the epidemic increased the contagion of cross-market risks and caused the carbon market to bear greater risks. The research results of this article have important guiding significance for environmental protection investment and emphasize the importance of formulating differentiated environmental protection policies in different time frames. Facing the dual challenges of global climate change and promoting the goal of carbon neutrality, governments and relevant institutions should pay close attention to changes in spillover effects between markets and timely adjust environmental protection policies to achieve maximum results.

An intelligent cross-border transaction system based on consortium blockchain: A case study in Shenzhen, China.

Cross-border transactions have been more and more popular around the world. However, the current cross-border transactions still have risks and challenges, e.g., differences in regulation policies and unbalanced profits of banks. To address this critical issue, we construct a new framework for the transaction system with the support of blockchain technology. In this paper, we propose a new consortium blockchain system, namely asymmetric consortium blockchain (ACB), to ensure the implementation of cross-border transactions. Different from traditional consortium blockchain, the new blockchain system could support the supernode to regulate all the transactions timely. Furthermore, the new smart contract is designed to lower the opportunity loss for each node and make the profits allocation system fairer. In the end, the numerical experiments were carried out based on the transactions of Shenzhen and Hong Kong. The results show that the proposed ACB system is efficient to make the profit allocation fairer for the participants and keep intelligent for the new cross-border transaction system.

Multi-period evaluation and selection of rural wastewater treatment technologies: a case study.

Rapid population growth and agricultural development are generating a considerable amount of effluents, which poses threats to the quality of rural water resources as well as sanitary conditions. However, with a range of rural wastewater treatment (WT) technologies available, one major problem facing the practitioners is which to choose as the most favorable option suited to specific areas. In this study, a novel decision-making framework is proposed to evaluate and select the optimal alternative in rural areas of Xi'an within multiple consecutive time periods. Firstly, an evaluation index system is constructed and picture fuzzy numbers (PFNs) are used to represent both evaluation levels and experts' refusal due to limitation of knowledge. Secondly, fuzzy analytical hierarchy process (FAHP) is applied to derive weights of criteria, which enables experts to assign fuzzy numbers to express their preferences for comparison judgments. Thirdly, evidence theory is utilized to obtain the aggregated values from multiple time periods. Finally, based on the belief intervals obtained, sequencing batch reactor (A4) is determined as the optimal rural WT technology in Xi'an from 2006 to 2020, whereas the membrane bio-reactor (A2) is the last option. The effectiveness of the proposed framework is further validated by comparative analysis. This research can hopefully serve as useful guidance for the assessment of rural WT technologies in various regions.

A fuzzy evaluation and selection of construction and demolition waste utilization modes in Xi'an, China.

The inadequate reuse and recycle of construction and demolition waste (C&DW) has been identified as a major issue, as it implies the depletion of natural aggregates, massive occupation of landfill and inefficiency of construction industry. However, a holistic view involving economic, technical and comprehensive dimensions has rarely been adopted for C&DW utilization evaluation against both qualitative and quantitative criteria. In this study, we propose a framework in a heterogeneous group decision-making environment to solve the C&DW utilization mode selection problem by integrating the Choquet integral and the elimination and choice translating reality (ELECTRE) method with two data forms, that is, interval-valued hesitant fuzzy numbers and real numbers. Firstly, an evaluation index system is constructed to assess multiple representative C&DW utilization modes in Xi'an, China. Secondly, a novel method is proposed to apply the Choquet integral for aggregation of evaluation values and fuzzy ELECTRE for outranking of C&DW utilization modes after the heterogenous evaluation data are unified into interval numbers. Thirdly, to illustrate the application of the proposed framework, this paper evaluates four typical C&DW utilization modes based on a case study in Xi'an, China, and the result shows that the most preferable mode is A3 (off-site crushing, roadbed backfilling). Finally, a comparative analysis is conducted to verify the effectiveness of this framework. This study presents useful findings to C&DW practitioners and can help avoid intuitive selection among available C&DW utilization modes.