Can environmental sustainability be decoupled from economic growth? Empirical evidence from Eastern Europe using the common correlated effect mean group test

The European Union(EU) and Organisation for Economic Co-operation and Development(OECD) aim to develop long-term policies for their respective member countries. Having observed increasing dangers to the environment posed by rising economic growth, they are seeking pathways to enable policy action on economic growth and environmental sustainability. Given the facts in theoretical and empirical studies, this study assessed the validity of the decoupling hypothesis by investigating asymmetricity in the relationship between environmental sustainability and economic growth in nine Eastern European countries from 1998 to 2017 using the cross-section augmented Dickey-Fuller(CADF) unit root, panel corrected standard error(PCSE), common correlated effect mean group(CCEMG), and Dumitrescu Hurlin causality approaches. Both population growth and drinking water are used as controlled variables. The outcomes establish strong cointegration among all the variables of interest. According to the results of CCEMG test, economic growth exerts short-term environmental degradation but has long-term environmental benefits in Eastern Europe;and population growth and drinking water exert a positive effect on environmental sustainability in both the short-and long-run. The results of Dumitrescu Hurlin causality test indicate that environmental sustainability is unidirectionally affected by economic growth. Based on these outcomes, we suggest the following policies:(1) the EU and OECD should implement member-targeted policies on economic growth and fossil-fuel use towards regulating industrial pollution, water use, and population control;and(2) the EU and OECD member countries should invest in environmental technologies through green research and development(R&D) to transform their dirty industrial processes and ensure productive energy use.

Correlation between indoor and outdoor corrosion tests for coal train body steel in a coal medium environment

Q345B carbon steel as well as Q450NQR1 and S500AW weathering steels were subjected to outdoor exposure corrosion tests in coal environments and indoor periodic immersion accelerated corrosion tests with a simulated coal leaching solution.The corrosion kinetics were studied by the weight loss method,and the corrosion morphology and corrosion product composition were observed and analyzed by scanning electron microscopy,energy-dispersive spectroscopy and X-ray diffraction.Afterward,correlation analysis of the indoor and outdoor tests was carried out by the gray correlation analysis method.The results show that the relationship between the corrosion weight loss and corrosion time of the three steels conforms to follow the exponent power law.In particular,Q450NQR1 steel has the best corrosion resistance.The types of corrosion products and the distribution of elements in the rust layer of the three steels are similar in the indoor and outdoor tests.The gray correlation degrees of the three steels in the indoor and outdoor tests are all greater than 0.6;thus,the two corrosion tests have a good correlation.Based on this,the accelerated simulation test method of the coal leaching solution is determined,and life prediction models of three steels in coal leaching solution are established to simulate the corrosion of the bottom board and side board.

Effects of Rainfall and Underlying Surface on Flood Recession——The Upper Huaihe River Basin Case

The effects of rainfall and underlying surface conditions on flood recession processes are a critical issue for flood risk reduction and water use in a region.In this article,we examined and clarified the issue in the upper Huaihe River Basin where flood disasters frequently occur.Data on 58 rainstorms and flooding events at eight watersheds during 2006–2015 were collected.An exponential equation(with a key flood recession coefficient)was used to fit the flood recession processes,and their correlations with six potential causal factors—decrease rate of rainfall intensity,distance from the storm center to the outlet of the basin,basin area,basin shape coefficient,basin average slope,and basin relief amplitude—were analyzed by the Spearman correlation test and the Kendall tau test.Our results show that 95%of the total flood recession events could be well fitted with the coefficient of determination(R2)values higher than 0.75.When the decrease rate of rainfall intensity(Vi)is smaller than 0.2 mm/h2,rainfall conditions more significantly control the flood recession process;when Vi is greater than 0.2 mm/h2,underlying surface conditions dominate.The result of backward elimination shows that when Vi takes the values of0.2–0.5 mm/h2 and is greater than 0.5 mm/h2,the flood recession process is primarily influenced by the basin’s average slope and basin area,respectively.The other three factors,however,indicate weak effects in the study area.

A novel multi-level model for quasi-brittle cracking analysis with complex microstructure

The paper presents a novel multi-level model for quasi-brittle cracking analysis.Based on the partition of unity and information transmission technology,it provides a new non-re-meshing way to describe the cracking phenomenon in structures constructed from materials with complex microstructures.In the global model,the concept of the material particle is defined and the basic unknowns are the boundary displacements of these particles,which is different from the concept of the traditional displacement field.A series of enrichment functions with continuous steps is proposed,describing the boundary displacement affected by crack bands and allowing the intersections of crack bands with particle boundaries a priori unknown.Simultaneously,additional equations are introduced to determine element status and make the degrees of freedom of the global model remain at a stable level.Compared with previous research by our group,where the local description is equal to the global description on the boundary of a material particle,the introduced enrichment functions enable more accurate capture of the characteristics of the crack band.The model avoids the complex and dynamic model adjustments due to the activation and exit of representative volume elements(RVEs)and the accuracy of the description of the crack pattern can be ensured.The RVEs are activated at first,but then many of them exit the computation due to the unloading which reduces many of the degrees of freedom.Two examples of concrete specimens are analyzed,and the concrete fracture experiment and the digital image correlation(DIC)test are conducted.Compared with the reference solutions and the experimental data,even though the microstructure of concrete is very complex,the cracking process and crack pattern can be obtained accurately.