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Unmanned surface vehicles (USVs) are playing a significant role in the marine science and engineering field, e.g., they have been widely used in measuring ocean waves and currents. However, their operation time and range are limited by the energy carried by internal batteries, and this challenge needs to be urgently addressed. In this study, a novel USV concept that can harvest vibration energy excited by ocean waves in the heaving and pitching direction is presented, which provides a sustainable and continuous power supply. A fully coupled wave-to-wire model that considers the viscous damping force is developed to investigate the dynamics and electric power performance of this novel device under site-specific realistic wave climates, with the external electric load optimally tuned for each sea state. Besides, the influence of the forward speed, geometric size, mass ratio and end-stop spring is studied. Numerical results show that the proposed USV in a freely floating situation can efficiently capture and convert harvested energy into electricity with a wave-to-wire efficiency of up to 20. 21 %. Additionally, it can generate an annual mean electric power of 29.73 W, under the wave climates of the national wave energy test site in China. • A novel wave-powered unmanned surface vehicle is designed. • A fully coupled wave-to-wire model is developed. • A high wave-to-wire efficiency up to 20.21% is obtained. • An annual mean electric power of 29.73 W is achieved by the USV. [ABSTRACT FROM AUTHOR]

Improving capacity utilization (CU) is a critical way for China to promote economic transformation and achieve sustainable development. As a market-based environmental regulation proposed to achieve a low-carbon economy and green transformation, whether emission trading system (ETS) can improve CU deserves an in-depth study. We conduct an empirical study by constructing a multi-period difference-in-differences model with 1,037 Chinese A-share listed firms from 2004 to 2020 as the research sample. The result shows that the ETS can significantly improve CU, which still holds after a series of robustness tests. The mechanism analysis shows that the ETS improves CU through three mechanisms: stimulating green innovation, restricting over-investment, and alleviating financing constraints. Based on the heterogeneity analysis, the improvement of CU by ETS is greater among listed firms in heavy-polluting industries, with good ESG performance, excess leverage, and central state ownership. Our study supports the global implementation of the ETS and provides ideas for resolving overcapacity in the context of global decarbonization. [ABSTRACT FROM AUTHOR]

Abstract: GPR (Ground penetrating radar) is one kind of the detection technologies with rapid, non-destruction, uninterrupted detection, and high-resolution. GPR can be applied to detect underground holes and loose soil layer and the other baneful anomalies, and therefore is widely applied to hole survey of the subway project in recent years. Based on briefly describing engineering geological background between F station and L station of a subway project in Beijing, this paper gives the arrangement method of GPR survey line in the construction area of shield method, analyzes detection results, verifies an anomaly by spading, determines the distribution range and its characteristic of the hole anomalies. The results showed that three obvious anomalies were detected in the area between F station and L station, and seriously loose soil layer was the cause of No. 1 and No. 3 anomalies, and hole was the cause of No. 2 anomaly. Thereby the anomalies of loose soil layer and hole could be detected accurately by the GPR technology, and then basic data of underground holes could be obtained. On the base of analyzing these data, effective measures could be adopted to avoid the hidden danger, then the safety of subway construction and surrounding environment of the subway project could be ensured. [Copyright &y& Elsevier]