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[en] As the largest emitter of CO2 emissions, the installed capacity of thermal power generation in China is facing more and more strict restrictions, since the Chinese government proposed to dissolve overcapacity and intends to solve the problem of continuous reduction in utilization rate of electricity sector. Regretfully, the impact of power-generating capacity and its utilization on carbon emissions in the power sector has not yet been addressed. In this study, we incorporate the interaction between capacity and utilization of power sector into the dynamic spatial Durbin model, and estimate the specific impact on carbon dioxide emissions from the power sector based on the panel data set of China’s provinces during 1991–2015. The results show that both installed capacity and utilization rate have positive effects on CO2 emissions. Interestingly, the estimation coefficient of their interaction term is negative, implying that the carbon emission reduction effect derives from the conflicting performance of capacity governance and utilization efficiency. Besides, the advantage of the emerging econometric method, the dynamic spatial Durbin model (SDM) with provinces and time-period fixed effects, is that it can estimate spatial interaction effects among the provinces and neighboring provinces and decompose those effects into two parts: long-term and short-term. However, the estimates indicate that only capacity has roughly significant spatial spillovers. As a result, dissolving overcapacity of thermal power generation and a necessary interprovincial coordination will promote carbon emission reduction rather than investing in coal-fired power plants, and the power authority should turn to alternative investment in cleaner power generation technologies.
[en] In the present work, an experimental investigation was conducted to study the influence of adding aluminum oxide nanoparticles (Al2O3) with different average particle sizes as additive to blends of diesel and waste plastic oil (WPO) on performance, emission, and combustion attributes of single-cylinder diesel engine operated at a constant speed. Two samples of Al2O3 nanoparticle with average particle sizes of 20 and 100 nm were dispersed into a WPO20 blend containing 20% of WPO and 80% of diesel in the mass fractions of 10 and 20 ppm using ultrasonic stabilization. The experimental recordings revealed a decrease in engine performance and increase in all emission constituents while replacing diesel with WPO20. However, the addition of both 20- and 100-nm-sized Al2O3 nanoparticles into WPO20 was found to enhance the brake thermal efficiency (BTHE) by 12.2 and 8.9% respectively and decrease the brake-specific fuel consumption (BSFC) by 11 and 8% respectively. The emission constituents such as carbon monoxide (CO), hydrocarbons (HC), nitric oxide (NO), and smoke opacity were minimized by the addition of both 20- and 100-nm-sized nanoparticles into WPO20 blend. However, the reduction of emissions was better for 20-nm-sized particles compared with that of 100-nm-sized particles. The combustion attributes such as cylinder pressure, heat release rate (HRR), and rate of pressure rise (RPR) were raised with shortened ignition delay (ID) by the addition of both sized nanoparticles. Overall, the inclusion of 20-nm-sized nanoparticles performs better catalytic activity to enhance the engine output characteristics along with minimum exhaust emissions.
[en] Coal fires are global disasters, and China suffers the most serious coal fire disasters in the world. This paper introduces detailed detection and extinguishing methods for the wide range and complex coal fires at the No. 1 well in the Fukang mining area. First, the characteristics of the large and complex coal fire areas in the No. 1 well in the Fukang mining area are introduced, and 5 large fire areas are detected using the comprehensive detection range method, which detects fire areas before fire engineering practices are implemented. From the characteristics of this large-scale, complex coal fire, the zonal fire extinguishing scheme is formulated, designed, and applied, and the “shallow open fire stripping—construction of the boundary isolation zone—drilling and grouting in the deep fire area” series of events is utilized in the zonal fire extinguishing scheme. A new type of sodium silicate gel in compressive moisturizing plastic packing materials is used, an automatic grouting system is developed, and effective grouting processes are proposed, which can be adjusted according to the grouting effect analysis of the grouting parameters to determine the natural sedimentation and diffusion radius. After the construction was completed, the fire extinguishing effect was tested, revealing that the temperature in the fire zone cooled in a short time, and no subsequent heating phenomenon occurs. The method proposed in this paper provides guidance and a reference for other coal fires in the world.
[en] In order to achieve a sustainable development of economy and ecological environment, starting from the systemic thinking and systemic approach, this paper regards China’s economic development and ecological environment protection as a whole system. Firstly, the negative index of M2 is introduced to correct the GDP bubble, and constructed the architecture model of the economy-ecological environment system. Then, this research establishes an evaluation index system using the analytic hierarchy process and Yaahp software and obtains its comprehensive evaluation value. After that, this research builds the Lotka-Volterra coordination degree model and uses the China data from 1997–2016 to analyze the mutual influencing factors and coupling coordination degree, and carries out the empirical and experimental tests to obtain the overall coordination relationship between economy and ecological environment systems. The results of the study show that the trend of economy-ecological environment coordination degree in China has changed from relatively coordinated to moderately uncoordinated in the latter 20 years; the coordination degree decreased from 0.8996 to 0.4842. Although, the situation has a rebound in the latter 2 years, the situation is still not optimistic. In addition, even the modified model of economic subsystem plus M2 did not change the original changing trend, and only changed the magnitude of the gap, thus revealing that the imbalance of economic development is much more serious than the impact of overissue currency on the ecological environment. This study provides a new basis for research decisions such as the adjustment of the economic growth rate and the optimization of ecological environment.
[en] Dibutyl phthalate (DBP), a persistent environmental pollutant, can induce neural tube abnormal development in animals. The possible effects of DBP exposure on human neural tube defects (NTDs) remain elusive. In this study, the distribution of DBP in the body fluid of human NTDs was detected by GC-MS. Then, chick embryos were used to investigate the effects of DBP on early embryonic development. Oxidative stress indicators in chick embryos and the body fluid of human NTDs were detected by ELISA. The cell apoptosis and total reactive oxygen species (ROS) level in chick embryos were detected by whole-mount TUNEL and oxidized DCFDA, respectively. The study found that the detection ratio of positive DBP and its metabolites in maternal urine was higher in the NTD population than that in normal controls. 8-hydroxy-2 deoxyguanosine (8-OHDG) and malondialdehyde (MDA) were evidently upregulated and superoxide dismutase (SOD) was observably downregulated in amniotic fluid and urine. Animal experiments indicated that DBP treatment induced developmental toxicity in chick embryos by enhancing the levels of oxidative stress and cell apoptosis. MDA was increased and SOD was decreased in DBP-treated embryos. Interestingly, the supplement of high-dose choline (100 μg/μL), not folic acid, could partially restore the teratogenic effects of DBP. Our data collectively suggest that the incidence of NTDs is closely associated with DBP exposure. This study may provide new insight for NTD prevention.
[en] Although the viscosity behavior of bacteria and extracellular polymeric substances (EPS) in flocculent activated sludge (FAS) and aerobic granular sludge (AGS) has been investigated, no studies have explored the role of viscosity in microbial attachment in pure culture. This study investigated the viscosity behavior of bacteria and EPS. The results showed that bacteria and their EPS exhibited non-Newtonian fluid and shear-thinning behavior. The viscosity of bacteria and EPS was 1.55–3.80 cP and 1.10–2.40 cP, respectively, while the attachment of bacteria (optical density at 600 nm) was 0.1426–3.1015. Bacteria with high attachment secreted EPS with a higher viscosity (2.40 cP), whereas those with weak attachment expressed EPS with a lower viscosity (1.10 cP). Viscosity and microbial attachment or extracellular polysaccharide (PS) content were significantly positively correlated. PS content was the source of bacterial viscosity, and β-polysaccharide played a more important role in viscosity and microbial attachment than α-polysaccharide. Thus, viscosity plays a critical role in microbial attachment, and high viscosity and PS content result in high microbial attachment, which is beneficial to the granulation process of AGS.
[en] Thermal power plants are the main source of carbon dioxide emissions in China. Beijing-Tianjin-Hebei and their neighborhood provinces are the most polluted regions in China. Environmental efficiencies of 528 thermal power plants were evaluated through metafrontier epsilon-based measure, which aimed to overcome the invalid inferences of radial or non-radial model. We also analyzed the heterogeneity of environmental efficiency across different regions by considering environmental technology differences. Bootstrap regression was used in order to testify three different hypotheses to address the disadvantages of conventional regression. We found that environmental efficiency in Beijing and Tianjin is higher than the other regions and is becoming divergent. In addition, coal consumption intensity negatively affects environmental efficiency. Large-scale power stations are more environmental efficient than smaller ones. Longer equipment utilization hour can enhance energy performance of power stations, which can decrease carbon emissions and increase environmental efficiency. It is better to promote technology transfer from regions with higher environmental efficiency to regions with lower environmental efficiency. Low-carbon technologies should be promoted to decrease carbon emissions.
[en] The use of allelopathic compounds is an alternative for weeds control, since they present low toxicity when compared with the synthetic herbicides, that may cause several damages, as the contamination of the environment. Our objective was to determine the chemical composition and allelopathic properties of the essential oils of Psidium cattleianum, P. myrtoides, P. friedrichsthalianum, and P. gaudichaudianum on the germination and root growth of Lactuca sativa and Sorghum bicolor, and to evaluate their action on the cell cycle of root meristematic cells of L. sativa. The main compound found in all the studied species was (E)-caryophyllene (P. cattleianum—23.4 %; P. myrtoides—19.3%; P. friedrichsthalianum—24.6% and P. gaudichaudianum—17.0%). The different essential oils were tested at different concentrations on L. sativa and S. bicolor, reducing germination, germination speed index, and root and shoot growth of lettuce and sorghum seedlings. The cytotoxicity and aneugenic potential of these oils were evidenced by the reduction of the mitotic index and increase of the frequency of chromosomal alterations in L. sativa. The essential oils of the species of Psidium studied have potential to be used in weeds control.
[en] In the present research, investigation of the practical utility of barberry stem powder (BSP) and barberry stem ash (BSA) for humic acid (HA) removal from an aqueous medium by adsorption was carried out. The adsorption process was tested by varying of pH (3–11), reaction time (5–20 min), initial HA concentration (5–40 mg/L), adsorbent dosage (1–4 g/L), and temperature (15–35 °C). The isothermal results revealed that the adsorption process is favorable for both used adsorbents and it is highly described using the Freundlich and Langmuir models (R2 > 0.960). Also, the maximum uptakes of BSP and BSA for HA were 20.220 and 16.950 mg/g at the abovementioned optimized conditions (pH = 7, reaction time = 10 min, temperature = 15 °C, initial HA concentration = 40 mg/L, and adsorbent amount = 1.0 g/L), respectively. The results achieved from the fitting of the experimental data with Dubinin-Radushkevich isotherm model showed that the HA molecules are adsorbed onto the BSP and BSA by physiosorption process. From the thermodynamic study, it appeared that the biosorption process of the HA onto two studied adsorbents was of exothermic nature. The kinetics of the adsorption process of HA has been found to be pseudo-second-order model (R2 = 0.930–0.999). Thus, the results obtained from this paper elucidated that the BSP exhibited higher adsorption capacity in comparison to BSA, for HA removal up to permissible concentrations.
[en] China is currently the largest CO2 emitter in the world. Within China, more than 60% of CO2 emissions originate from high energy-intensive (HEI) industries. Therefore, controlling and reducing CO2 emissions from HEI industries is crucial if China is to achieve its 2030 emission reduction targets. This study aims to investigate regional differences in the impact of HEI industries on CO2 emissions in China. This paper presents an analysis of the impact of HEI industries on CO2 emissions at the national and regional levels using a modified STIRPAT model and provincial panel data from 2000 to 2015 in China. The results show that HEI industries are significant contributors to China’s CO2 emissions owing to the growth in industries, coal-based energy structure, low level of technology, and outstanding conduction effects. The impact intensity of HEI industries on CO2 emissions decreases from the western to the central and eastern regions in China because of a huge regional difference in industrial structure, energy structure, R&D investment, and industrial transfer. Our findings have important implications for policymakers in China by indicating that regional policies concerning HEI industries should be differentiated to successfully reduce CO2 emissions and meet national targets.