ALBERT

Description: This paper pays attention to magnetic flux linkage optimization of a direct-driven surface-mounted permanent magnet synchronous generator (D-SPMSG). A new compact representation of the D-SPMSG nonlinear dynamic differential equations to reduce system parameters is established. Furthermore, the nonlinear dynamic characteristics of new D-SPMSG equations in the process of varying magnetic flux linkage are considered, which are illustrated by Lyapunov exponent spectrums, phase orbits, Poincaré maps, time waveforms and bifurcation diagrams, and the magnetic flux linkage stable region of D-SPMSG is acquired concurrently. Based on the above modeling and analyses, a novel method of magnetic flux linkage optimization is presented. In addition, a 2 MW D-SPMSG 2D/3D model is designed by ANSYS software according to the practical design requirements. Finally, five cases of D-SPMSG models with different magnetic flux linkages are simulated by using the finite element analysis (FEA) method. The nephograms of magnetic flux density are agreement with theoretical analysis, which both confirm the correctness and effectiveness of the proposed approach.

Description: The occurrence of fluoroquinolone antibiotics in wastewater has drawn great attention. Adsorption of widely used fluoroquinolone antibiotics (enrofloxacin and ofloxacin) in wastewater using bamboo biochar was investigated. More than 99% of fluoroquinolone antibiotics were removed from the synthetic wastewater through adsorption. Adsorption capacities of bamboo biochar slightly changed when pH increased from 3.0 to 10.0. The adsorption capacity of bamboo biochar increased sharply when the initial concentration of enrofloxacin or ofloxacin increased from 1 to 200 mg L−1 and then began to plateau with further increases in initial concentration. The maximum adsorption capacity (45.88 ± 0.90 mg·g−1) was observed when the ratio of bamboo biochar to fluoroquinolone antibiotics was 10. The enrofloxacin adsorption capacity of bamboo biochar decreased from 19.91 ± 0.21 mg·g−1 to 14.30 ± 0.51 mg·g−1 while that of ofloxacin decreased from 19.82 ± 0.22 mg·g−1 to 13.31 ± 0.56 mg·g−1 when the NaCl concentrations increased from 0 to 30 g·L−1. The adsorptions of fluoroquinolone on bamboo biochar have isotherms that obeyed the Freundlich model (r2 values were in the range of 0.990–0.991).

Description: IJERPH, Vol. 15, Pages 1808: Labor Off-Farm Employment and Cropland Abandonment in Rural China: Spatial Distribution and Empirical Analysis International Journal of Environmental Research and Public Health doi: 10.3390/ijerph15091808 Authors: Xin Deng Dingde Xu Yanbin Qi Miao Zeng Alleviating cropland misallocation is helpful for the sustainable development of agriculture. Does off-farm employment inevitably result in cropland misallocation (e.g., cropland abandonment) and threaten the sustainable development of agriculture? This study differs from prior studies in its view that off-farm employment does not necessarily result in cropland abandonment. Specifically, the study employs survey data from 8031 peasant households from 27 provinces in rural China and spatial statistics to analyze the distribution of off-farm employment and cropland abandonment. Empirical models (i.e., IV-Probit and IV-Tobit) are used to examine the quantitative relation between off-farm employment and cropland abandonment. The results are as follows. (1) The spatial distribution of off-farm employment or cropland abandonment differs among regions. Regions with a higher rate of off-farm employment show more cropland abandonment but a lower average area of cropland abandonment. (2) Off-farm employment has a significant and positive correlation with cropland abandonment. However, its square has a significant and negative correlation with cropland abandonment; i.e., there is an inverted U-shaped relationship between off-farm employment and cropland abandonment, with the turning point occurring at 46.00% off-farm employment. (3) Off-farm employment has a significant and positive correlation with the area of cropland abandonment. However, its square has a significant and negative correlation with the area; i.e., there is an inverted U-shaped relationship between off-farm employment and area, with the turning point occurring at 44.50% off-farm employment. This study reveals the relationship between off-farm employment and cropland abandonment and provides policymakers with references for use in developing sustainable agriculture.

Description: Sustainability, Vol. 10, Pages 1469: Exploration of the Industrial Spatial Linkages in Urban Agglomerations: A Case of Urban Agglomeration in the Middle Reaches of the Yangtze River, China Sustainability doi: 10.3390/su10051469 Authors: Yan Yu Qianwen Han Wenwu Tang Yanbin Yuan Yan Tong The study of industrial spatial linkages of urban agglomerations is crucial to recognizing spatial structure and optimizing regional division and cooperation. The existing studies often focus on external spatial interaction at the inter-city level, but few have considered complex internal economic linkages at the inter-sector level. In this study, we established an integrated framework by combining the wave effect gradient field with the gravity model. The wave effect gradient field was used to analyze the inter-sector relation, while the gravity model was adopted to explore the spatial interactions of industry at the inter-city level. The Urban Agglomeration in the Middle Reaches of the Yangtze River (UAMRYR) was taken as a case study, which demonstrates the applicability of the proposed framework. The results indicate that there exists an imbalanced development in the network of industrial linkages in the study region. Each subgroup has presented a self-organized spatial linkage network, but the linkages between subgroups are immature. Compared with other sectors, the high-tech and internet industrial sectors contribute most to economic linkages among cities. Thus, policymakers should take actions to strengthen the inter-subgroup spatial linkages and give priority to the high-tech industries, which is necessary for the integrated and sustainable development of UAMRYR.

Description: IJERPH, Vol. 14, Pages 970: Occurrence, Distribution, and Risk Assessment of Perfluoroalkyl Acids (PFAAs) in Muscle and Liver of Cattle in Xinjiang, China International Journal of Environmental Research and Public Health doi: 10.3390/ijerph14090970 Authors: Gehui Wang Jianjiang Lu Zhenni Xing Shanman Li Zilong Liu Yanbin Tong Despite risks associated with perfluoroalkyl acids (PFAAs) in many regions, little is known about their prevalence in Xinjiang. We determined the presence of 13 PFAAs in 293 beef muscle and liver samples collected in 22 cities covering northern, southern, and eastern Xinjiang using liquid chromatography, coupled with tandem mass spectrometry. Overall, the average values for PFAAs were relatively low compared with previous studies. Liver presented higher mean levels of total PFAAs at 1.632 ng/g, which was over 60-fold higher than in muscle (0.026 ng/g). Among the PFAAs analyzed, medium-chain compounds were dominant, accounting for more than 70% of the total. Perfluorooctane sulfonate (PFOS) was highly prevalent in the liver with the highest mean concentration (0.617 ng/g) and detection frequency (80%). When comparing the three regions of Xinjiang, we found differences in PFAA profiles, with the northern region showing the highest levels. Furthermore, the average daily intake and hazard ratios of PFOS and perfluorooctanoic acid varied by region, urban/rural environment, gender, ethnicity, and age. The highest risk value of 13 PFAAs was estimated to be 0.837 × 10−3, which is far below 1, indicating that there is no health risk posed by eating beef muscle and liver in Xinjiang.

Description: Peatlands play an important role in the global carbon cycle and potentially have a significant impact on regional climate change. Restoring and rewetting the degraded peatlands is an urgent task. However, effects of rewetting on the carbon emissions of peatlands remain poorly understood. In this study, the process of rewetting a piece of the degraded Zoige alpine peatland was experimentally simulated and the derived results were compared with those of natural rewetting by monitoring CO2 and CH4 fluxes and other environmental factors before and after rewetting. The natural rewetting results showed that rewetting decreased ecosystem respiration (ER) by about 60%. Furthermore, rewetting increased CH4 emissions by 127%, decreased total carbon emissions (TCE) from 270 to 157 mg CO2 m−2 h−1, and decreased TCE from the entire ecosystem by 42%. The results of the controlled experiment showed that ER decreased gradually as the degree of rewetting was increased, and CH4 fluxes and changes in water level were significantly and positively correlated: CH4 fluxes increased from 0.3 (water level −20 cm) to 2.17 mg CH4 m−2 h−1 (water level 20 cm). After rewetting, the TCE of the whole ecosystem were significantly decreased. Regional observations showed that CO2 fluxes were significantly and negatively correlated to the water level; and the corresponding CO2 equivalent was significantly and positively correlated to the water level, while TCE were significantly and negatively correlated to the water level. Our findings indicate that rewetting can decrease carbon emissions and thus contribute in mitigating the adverse effects of climate change in alpine peatland.

Description: IJERPH, Vol. 15, Pages 1105: Mosses Are Better than Leaves of Vascular Plants in Monitoring Atmospheric Heavy Metal Pollution in Urban Areas International Journal of Environmental Research and Public Health doi: 10.3390/ijerph15061105 Authors: Yanbin Jiang Miao Fan Ronggui Hu Jinsong Zhao Yupeng Wu Mosses and leaves of vascular plants have been used as bioindicators of environmental contamination by heavy metals originating from various sources. This study aims to compare the metal accumulation capabilities of mosses and vascular species in urban areas and quantify the suitability of different taxa for monitoring airborne heavy metals. One pleurocarpous feather moss species, Haplocladium angustifolium, and two evergreen tree species, Cinnamomum bodinieri Osmanthus fragrans, and substrate soil were sampled in the urban area of different land use types in Wuhan City in China. The concentrations of Ag, As, Cd, Co, Cr, Cu, Mn, Mo, Ni, V, Pb, and Zn in these samples were analyzed by inductively coupled plasma mass spectrometry. The differences of heavy metals concentration in the three species showed that the moss species was considerably more capable of accumulating heavy metals than tree leaves (3 times to 51 times). The accumulated concentration of heavy metals in the moss species depended on the metal species and land use type. The enrichment factors of metals for plants and the correlations of metals in plants with corresponding metals in soil reflected that the accumulated metals in plants stemmed mostly from atmospheric deposition, rather than the substrate soil. Anthropogenic factors, such as traffic emissions from automobile transportation and manufacturing industries, were primarily responsible for the variations in metal pollutants in the atmosphere and subsequently influenced the metal accumulation in the mosses. This study elucidated that the moss species H. angustifolium is relatively more suitable than tree leaves of C. bodinieri and O. fragrans in monitoring heavy metal pollution in urban areas, and currently Wuhan is at a lower contamination level of atmospheric heavy metals than some other cities in China.

Description: Energies, Vol. 11, Pages 1556: Petrographic Controls on Pore and Fissure Characteristics of Coals from the Southern Junggar Coalfield, Northwest China Energies doi: 10.3390/en11061556 Authors: Sandong Zhou Dameng Liu Yidong Cai Zuleima Karpyn Yanbin Yao The productive potential of coalbed methane projects is controlled by pore and fissure characteristics, which are intrinsically related to coal petrology. This work attempts to identify the influence of petrographic factors on the development of pore and fissure systems in the southern Junggar Coalfield, Northwest China. Here, Middle Jurassic coal (lignite and subbituminous) petrology in coal seam No. 45 of the southern Junggar Coalfield (SJC) is studied with respect to the characteristics of pore and fissure structure with the aid of optical microscopes, scanning electron microscopy, mercury intrusion porosimetry, and nuclear magnetic resonance analysis. Maceral analysis shows coals at the SJC are dominated by vitrinite (38–87 vol %), with moderate quantities of inertinite (1–28 vol %) and liptinite (0.5–30 vol %). Decomposition of plants occurs under slightly oxic–anoxic conditions, with good tissue retention. Four types of coal facies are classified using petrographic indices, comprising (1) lower delta plain marsh, (2) lower delta plain fen, (3) upper delta plain wet forest swamp; and (4) piedmont plain moor. Pores and fissures are generally observed in telinite, collotelinite, fusinite, and semifusinite in SJC coals, indicating that the generation of pores and fissures is strongly influenced by coal macerals. Pore and fissure structures of coals in coal facies (1) appear weakly connected, whereas those in coal facies (2) reveal good connectivity. Coals in coal facies (3) and (4) show moderate connectivity between pore and fissure structure. Therefore, pore and fissure structures are significantly controlled by coal facies. This work provides practical recommendations and implementation methods for petrological studies in future coalbed methane exploration/development in the SJC. This study also serves to predict the physical properties of pores and fissures and interpret the control mechanism of coalbed methane production using coal petrology.

Description: Energies, Vol. 11, Pages 1817: A Real Options Analysis for Renewable Energy Investment Decisions under China Carbon Trading Market Energies doi: 10.3390/en11071817 Authors: Yanbin Li Min Wu Zhen Li Under the carbon trading mechanism, renewable energy projects can gain additional benefits through Chinese Certified Emission Reduction transactions. Due to the uncertainty of carbon trading system, carbon prices will fluctuate randomly, which will affect the investment timing of renewable energy projects. Thus, the value of the option will be generated. Therefore, renewable energy power generation project investment has the right of option. However, the traditional investment decision-making method can no longer meet the requirements of renewable energy investment in the current stage. In this paper, a real option model considering carbon price fluctuation is proposed as a tool for renewable energy investment. Considering optimal investment timing and carbon price, the model introduces a carbon price fluctuation as part of the optimization, studies the flexibility of enterprises’ delayed investment under the fluctuation of carbon price. A case study is carried out to verify the effectiveness of the proposed real option model by selecting a wind farm in North China. The model is expected to help investors to assess the volatility and risk of renewable energy projects more accurately, and help investors to make a complete plan for the project investment, thus promoting the efficient allocation of resources in the energy industry.

Description: Sustainability, Vol. 10, Pages 2612: Regional-Level Allocation of CO2 Emission Permits in China: Evidence from the Boltzmann Distribution Method Sustainability doi: 10.3390/su10082612 Authors: Yanbin Li Zhen Li Min Wu Feng Zhang Gejirifu DE To achieve the commitment of carbon emission reduction in 2030 at the climate conference in Paris, it is an important task for China to decompose the carbon emission target among regions. In this paper, entropy maximization is brought to inter-provincial carbon emissions allocation via the Boltzmann distribution method, which provides guidelines for allocating carbon emissions permits among provinces. The research is mainly divided into three parts: (1) We develop the CO2 influence factor, including per capita GDP, per capita carbon emissions, carbon emission intensity and carbon emissions of per unit industrial added value; the proportion of the second industry; and the urbanization rate, to optimize the Boltzmann distribution model. (2) The probability of carbon emission reduction allocation in each province was calculated by the Boltzmann distribution model, and then the absolute emission reduction target was allocated among different provinces. (3) Comparing the distribution results with the actual carbon emission data in 2015, we then put forward the targeted development strategies for different provinces. Finally, suggestions were provided for CO2 emission permits allocation to optimize the national carbon emissions trading market in China.