Wang F.,Beijing Normal University |
Wang F.,Shanxi University |
Wang X.,Beijing Normal University |
Zhao Y.,Beijing Normal University |
And 2 more authors.
Earth Science Informatics | Year: 2014
As the characterization of primary productivity of wetland ecosystem, the Normalized Difference Vegetation Index (NDVI) plays an important role in local ecosystem conservation for environmental management. In this paper, the correlations of NDVI and hydro-meteorological variables were studied in a water scarce area with emphasis on different land use types, namely water, wetland, residential land and farmland, during the growing seasons of 1999 and 2000. The significant NDVI changes were detected between spring and summer for all land use types. The correlation analysis revealed that the NDVI-temperature correlation (P < 0.001) was stronger than NDVI-precipitation correlation (P < 0.01 for farmland and P < 0.05 for others) in all land use types. In addition, water level had no significant correlation with NDVI at such a small time scale. The sensitivity differences in different land use types based on the determination coefficient of the linear regression models are: Rfarmland > Rwetland > Rresidential land > Rwater for NDVI and precipitation correlations (P < 0.05); and Rwater > Rwetland > Rresidential land > Rfarmland for NDVI and temperature correlations (P < 0.001). The results would be valuable for the understandings of effects of hydro-meteorological variables on NDVI changes, as well as the potential effect on land use and land cover. © 2013 Springer-Verlag Berlin Heidelberg.
Cheng M.,Northwest Agriculture and Forestry University |
Cheng M.,Northwest University, China |
Xiang Y.,Northwest Agriculture and Forestry University |
Xiang Y.,Shanxi Academy of Environmental Research |
And 4 more authors.
Catena | Year: 2015
Revegetation has been reported to be one of the most effective measures for reducing soil erosion on the Loess Plateau in China. The Yunwu observatory, located in the northwestern Loess Plateau of China, was selected to study the effect of vegetation succession on total carbon (C), aggregate C, and intra-aggregate particulate organic matter-carbon (iPOM-C) concentrations. The vegetation types studied, listed from the shortest to the longest enclosure duration order, were abandoned grazed grassland (Ab.G3), Hierochloe odorata Beauv. (Hi.O7), Thymus mongolicus Ronnm (Th.M15), Artemisia sacrorum Ledeb (At.S25), Stipa bungeana Trin Ledeb (St.B36), and Stipa grandis P. Smirn (St.G56) communities. Five sizes of aggregates were separated using the modified Yoder method (<0.25mm, 0.25-1mm, 1-2mm, 2-5mm and 5-8mm). Fine and coarse iPOM-C concentrations were isolated from the soil aggregates. The results showed that revegetation led to an increase in the percentage of aggregates in small macroaggregates (0.25-2mm) and thereby improved the uniformity of the soil aggregate size distribution. The concentration of bulk soil carbon ranged from 10.1gkg-1 to 29.7gkg-1 during vegetation succession. During the vegetation succession, with the exception of At.S25, the bulk soil carbon and aggregate carbon concentrations increased with recovery time. The fine iPOM-C concentrations were between 0.7 and 14.0gkg-1, which was significantly greater than the coarse iPOM-C concentrations. The coarse and fine iPOM-C concentrations exhibited different trends with vegetation restoration. In conclusion, vegetation restoration caused an increase in small macroaggregates, enhancing the uniformity of the soil aggregate size distribution and inducing greater soil organic carbon sequestration. © 2014 Elsevier B.V.
Zhang D.W.,Harbin Institute of Technology |
Chai C.Y.,Harbin Institute of Technology |
Yu Y.L.,Harbin Institute of Technology |
Li C.,Shanxi Academy of Environmental Research |
Feng Y.J.,Harbin Institute of Technology
Environment, Energy and Applied Technology - Proceedings of the 2014 3rd International Conference on Frontier of Energy and Environment Engineering, ICFEEE 2014 | Year: 2015
The high cultivation cost of microalgae biodiesel challenges its industrial application. An effective way to lower down cost is to couple the cultivation with the removal of NO in the microalgae- Fe(II)EDTA system. In this study, the impact of culture composition and cell density on NO removal and cell growth was investigated. It was found that the addition of Fe(II)EDAT increased the NO removal rate to 78.8%, nitrogen had indirect impact on NO removal but through algae cell growth. Within the nitrogen-free culture medium with Fe(II)EDTA, the highest lipid yield could reach to 48.3 mg/L. The system reached equilibrium state for the photosynthesis, which oxidized Fe(II) and reduced Fe(III) simultaneously. © 2015 Taylor & Francis Group, London.
Zhang D.,Harbin Institute of Technology |
Yu Y.,Harbin Institute of Technology |
Li C.,Harbin Institute of Technology |
Li C.,Shanxi Academy of Environmental Research |
And 4 more authors.
RSC Advances | Year: 2015
Microalgae harvesting is a relatively costly process in microalgae biodiesel production. In this study, electrocoagulation-flotation (ECF) was employed to harvest microalgae (Chlorella vulgaris). Higher current density achieved higher collection efficiency, but also resulted in higher energy consumption and increased levels of dissolved aluminium. At the same ratio of current density to initial cell density, collection efficiency decreased from 99.0% of 0.24 g L-1 to 30.5% of 1.17 g L-1 when the electrolysis time was 20 min. For stirring and aeration, the highest collection efficiency was 98.4%, obtained by stirring at 50 rpm for 20 min. This efficiency was nearly equal to the highest collection efficiency for aeration: 98.3% for 50 mL min-1 aeration at 30 min. Acidic and neutral culture conditions were beneficial due to the positively charged aluminium species in the culture; higher collection efficiencies (more than 98%) occurred with pH levels of 5-7 after 20 min. The lowest energy consumption of 0.61 kW h kg-1 was achieved at pH 5. In this research, ECF exhibited higher collection efficiency (99.4%) as compared to the 93.5% collection efficiency of chemical flocculation (Al2(SO4)3). This journal is © The Royal Society of Chemistry 2015.
Ding C.,Taiyuan University of Technology |
Ai G.,Taiyuan University of Technology |
Zhang K.,Shanxi Institute of Coal CAS Chemistry |
Yuan Q.,Shanxi Academy of Environmental Research |
And 4 more authors.
International Journal of Hydrogen Energy | Year: 2015
Carbon deposition, which may reduce the number of active sites or remove metal particles from the catalyst surface, is an urgent issue for the partial oxidation of methane (POM) to synthesis gas. To solve this problem, Ni/ZrO2@SiO2 catalysts were prepared by a modified Stöber method. The investigation was focused mainly on the role of ZrO2 addition and mesopore silica shell in preventing carbon deposition. The structural properties and carbon deposition of catalysts were characterized by XRD, TEM, N2 adsorption and TG techniques. The oxygen transfer capacity and reducibility of catalysts were evaluated by oxygen storage capacity (OSC) and temperature programmed reduction (TPR). Inspiringly, the Ni/ZrO2@SiO2 catalyst was proved to be more active and possessed less carbon deposition due to the higher reducibility and oxygen storage/release capacity. Importantly, compared with the support catalysts, the catalysts coated by mesopore silica shell showed exceptional resistance to coking, because the edge and corner atoms favor to carbon deposition were selectively blocked by silica shell, in addition, the size of the pore channel prevented growth up of carbon filament. © 2015 Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Lian K.-M.,Zhongtiaoshan State owned Forest Administration of Shanxi |
Wu Y.-J.,Zhongtiaoshan State owned Forest Administration of Shanxi |
Zhang L.,Shanxi Academy of Environmental Research |
Zhao L.-L.,CAS Research Center for Eco Environmental Sciences |
Zhang F.,Shanxi University
Chinese Journal of Ecology | Year: 2015
Based on the data from the field investigation of 42 quadrats with 37 dominant species, the structure, species composition and distribution of wild Castanea mollissima communities in Taikuan River Nature Reserve, Shanxi and the relationship of community and environment were investigated by TWINSPAN and DCA. The results showed that C. mollissima communities were divided into 11 associations by TWINSPAN, and the distribution of the communities could comprehensively reflect the influences of disturbance, slope direction and soil organic matter on the communities. The results by DCA ordination indicated that the important factors impacting the community distribution were slope direction, terrain and soil type. The first axis of DCA ordination mainly represented the influence of the slope and slope direction on the communities. The relationship between the community and the environment, mainly reflected by the second axis, was not obvious; however, the diagonal of DCA ordination reflected the variations of the communities and the thickness of forest floor. Moreover, the DCA ordination analysis showed that the 37 dominant species had similar patterns. To some extent, community type was dependant on the distribution pattern of dominant species. © 2015, editorial Board of Chinese Journal of Ecology. All rights reserved.