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An empirical study on environmental efficiency measurements and influencing factors

100%

Chen Y. , Li L. , Yu J. , Tsai S.-B. , Wang J.

Ecological Chemistry and Engineering. S

2020

tom Vol. 27, nr 4

543--553

Airlines are an important part of the comprehensive transportation system. Therefore, it is of great practical significance to empirically analyse the measurement of airlines’ environmental efficiency and influencing factors. Adopting the SBM-DEA model, this study measured the environmental efficiency of 20 Chinese airlines between 2010 and 2017 and empirically analysed the factors influencing their environmental efficiency using a Tobit regression model. Spring Airlines, China Southern Airlines, and Hainan Airlines were found to have the highest environmental efficiency. Tianjin Airlines, Hebei Airlines, and China Express Airlines had the lowest environmental efficiency. The Tobit regression results showed that average flight distance, load factor, market share, and proportion of cargo and mail turnover had a significant positive effect on airline environmental efficiency. Fuel consumption per ton-km had a significant negative effect on airline environmental efficiency.

Study on the restoring force model for the high‑speed railway CRTS III Slab Ballastless Track

86%

Liu L. , Jiang L. , Zhou W. , Yu J. , Peng K. , Zuo Y.

Archives of Civil and Mechanical Engineering

2022

tom Vol. 22, no. 3

art. no. e148

The China Railway Track System III (CRTS III) Slab Ballastless Track (SBT) is currently one of China's most widely used track structures. The elastic-plastic restoring force hysteresis model of CRTS III SBT is the primary problem that should be solved for the elastic-plastic seismic response analysis of high-speed railway (HSR) CRTS III SBT systems. To study the elastic-plastic restoring force hysteretic model of CRTS III SBT, four CRTS III SBT specimens were designed in this study and subjected to low-cycle reciprocating load tests. The efects of different thickness of rubber pad on the hysteretic curve, skeleton curve, and other performance of CRTS III SBT specimens were determined. In addition, the restoring force characteristics and hysteretic trends of CRTS III SBT specimens were ascertained. Furthermore, a load-displacement restoring force model for CRTS III SBT was built. Its results were compared with the test results, thus validating the load-displacement restoring force model rationality. The load-displacement restoring force model developed in this study is simple to calculate, laying a solid foundation for analyzing the elastic-plastic seismic responses of HSR CRTS III SBT systems.