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The future of mountain agriculture amidst continual farm-exit, livelihood diversification and outmigration in the Central Himalayan villages

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Journal of Mountain Science 2019年第4期16卷 755-768页

作者： Niyati NAUDIYAL Kusum ARUNACHALAM Ujjwal KUMAR school of environment and Natural resources Doon University

Agrarian patterns in mountain ecosystems have seen a considerable change in the past decades with a vast proportion of the population abandoning traditional agriculture and diversifying their livelihood options, primarily through out-migration. This trend is especially common amongst the subsistence based family-farming communities in developing countries. This study aims at assessing methods of livelihood diversification and factors influencing farm-exit in Central Himalayan villages of Uttarakhand, India, while trying to understand local perspectives on challenges in pursuing agriculture as a viable livelihood option. We collected qualitative and quantitative data from 951 households across 60 villages evenly distributed across six hill districts of Uttarakhand, using key-person interviews and household surveys. The results of the study highlight that farm-exit is significantly influenced by livelihood diversification, number of migrants, number of female family members, and availability of irrigation facilities. In general, perception of the respondents towards agriculture as a viable livelihood option is rather unenthusiastic, with 87% of the respondents citing human wildlife conflict as the main challenge in pursuing farming, amongst several other challenges. Diversification is an integral component of present rural economy with 80.13% of the total population dependent on more than one source of income, to maintain their livelihoods. However, there is no statistically significant influence of livelihood diversification on annual income of the household. If agro-based entrepreneurial ventures are to be promoted in the region there is an urgent need for timely introduction of radical policy, institutional, and land-reforms. Economic uplifting of the local population through such efforts can also be a possible solution to the growing trends of out-migration in the state.

关键词： Agriculture Diversification Rural livelihoods Migration Himalaya

Recovery of copper from copper slag using a microbial fuel cell and characterization of its electrogenesis

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International Journal of Minerals,Metallurgy and Materials 2017年第6期24卷 621-626页

作者： Wei-ping Liu Xia-fei Yin school of Chemistry and environment engineering Jiangsu University of Technology school of environment and Civil engineering Jiangnan University

The microbial fuel cell, which can convert the chemical energy of organic matter into electricity via the catalytic action of microorganisms, is a novel environmentally friendly technology for wastewater treatment and energy generation. The electrical energy generated by the microbial fuel cell can be used as an alternative to a traditional external power source required to extract copper via electrolytic treatment. A dual-chamber microbial fuel cell(DMFC) for the treatment of copper slag sulfuric acid leach liquor was constructed. The electrogenesis performance of the DMFC and its ability to extract copper from the copper slag leachate were investigated. The results demonstrated that the maximum voltage was 540 mV when the DMFC achieved steady-state operation. The removal rate of copper ions was greater than 80.0%, and the maximum value was 92.1%. Moreover, X-ray diffraction and scanning electron microscopy were used to characterize the cathodal products. The results showed that the product deposited onto the cathode was copper and that its morphology was similar to that of the electrolytic copper powder. The DMFC can generate electricity and recover copper from copper slag simultaneously.

关键词： microbial fuel cells copper slag recovery copper electrogenesis

Formative mechanism of preferential solution flow during dump leaching

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Journal of Central South University of Technology 2006年第5期13卷 590-594页

作者：吴爱祥尹升华刘金枝杨保华 school of Civil and environment engineering University of Science and Technology Beijing school of resources and Safety engineering Central South University

Preferential flow is a rapid movement of solution through pores caused by coarse ores. Macropore is the main factor for the preferential flow. Macropore can be defined from three aspects. Segregation of the ores during dumping was studied according to particle kinematics. Small ores become smaller under the effect of acid and weathering. Clay in the rainwater from the hillside precipitates in the dump. Segregation and fine ores are the main causes in macropore. The permeability in coarse ores is better than that in fine ores. The mechanism in the preferential flows was studied combining the fast conducting effect of the macropore. Experimental result shows that, at certain application rate, fine ore area is saturated while large volume of solution flows laterally to the coarse ore area and leaks out quickly through the macropores. Thus the mechanism of preferential solution flows is further illustrated.

关键词： macropore segregation sliming permeability preferential solution flow

A stability study of goaf based on mechanical properties degradation of rock caused by rheological and disturbing loads

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International Journal of Mining Science and Technology 2015年第5期25卷 741-747页

作者： Xiao Chao Zheng Huaichang Hou Xiaolin Zhang Xiaojun school of resources and environment Shandong University of Technology

Based on the classical static theory and static numerical simulation,the static method could not accurately reflect the stability of goaf where the rocks on the pillar and roof are influenced by Theological and blasting disturbance for a long *** to the test from the site,an experimental study was made in Theological and dynamic *** that,on the basis of variable rock mechanics parameters from the experimental data,numerical simulation was used to analyze the vertical stress distribution of goaf,vertical displacement and plastic area of roof in the "deterioration" caused by Theological and blasting,which shows that the mechanics properties of the rock were greatly influenced by Theological,and dynamic *** results of the experimental study and numerical simulation show that the mechanics properties of rock are greatly influenced by Theological and dynamic *** a result,the stability of goaf is greatly ***,by comparing golf monitoring results with the analysis of theoretical calculation,it was found that the results were approximately the same,which testifies the reliability of the *** method provides a new way of studying the stability of goaf as well as laying a basic foundation for future safety management.

关键词： Stability of goaf Rheological disturbance experiment Rock mechanics parameters Numerical simulation

The best hydraulic section of horizontal-bottomed parabolic channel section

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Journal of Hydrodynamics 2017年第2期29卷 305-313页

作者：韩延成高学平徐征和 school of resources and environment University of Jinan State Key Laboratory of Hydraulic engineering Simulation and Safety Tianjin University

The best hydraulic channel section makes the maximum flow capacity for the same flow cross-area, and the minimum cross-area and wetted perimeter for the same discharge. The construction cost can be reduced nearly to the minimum at the same time The horizontal bottom parabolic section （HBP section） is a composite section. It is important for design to find the best combination form of the horizontal bottom and the parabolic sides. This paper studies the best hydraulic section and its hydraulic characteristics. The explicit formulae are proposed to determine the dimensions and the best combination form of the horizontal bottom and the parabolic sides. These explicit formulae and the parameters make it easy to design the channel. It is shown that the ratios of the surface width to the depth and the bottom width to the depth are constant for the best hydraulic section. The comparisons with the classic parabolic, rectangular, trapezoid, triangular, semi-cubic and horizontal-bottomed semi-cubic sections show that the HBP section has the largest flow capacity and the shortest wetted perimeter for the same flow area, and has the smallest flow area for the same discharge. It is indicated that the parabolic side parts of the best hydraulic HBP section are different from those of the classic section. The results of the best hydraulic section of the classic parabolic channel cannot be applied directly to the HBC section.

关键词： Channel parabolic shape horizontal-bottomed best hydraulic section

Effects of Silver Nanoparticles on Soil Microbial Communities and Bacterial Nitrification in Suburban Vegetable Soils

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Pedosphere 2017年第3期27卷 482-490页

作者： WANG Juan SHU Kunhui ZHANG Li SI Youbin school of resources and environment Anhui Agricultural University

Silver nanoparticles （AgNPs） are widely used antimicrobial compounds; however, they may pose a threat to non-targeted bacteria in the environment. In this study high-throughput sequencing was used to investigate the effects of different concentrations of AgNPs （10, 50, and 100 mg kg-1） on soil microbial community structure during short-term （7 d） exposure. The amounts of Acidobacteria, Actinobacteria, Cyanobacteria, and Nitrospirae significantly decreased with increasing AgNP concentration; meanwhile, several other phyla （e.g., Proteobacteria and Planctomycetes） increased and dominated. Nitrosomonas europaea, a well-characterized ammonia- oxidizing bacterium, was used to study the sensitivity of bacteria to AgNPs and ionic silver （Ag＋）. Flow cytometry was used to monitor the toxicity of low （1 mg L-l）, middle （10 mg L-l）, and high concentrations （20 mg L-1） of AgNPs, as well as Ag＋（1 mg L-1） released into the medium from 20 mg L-1 concentration of AgNPs, towards N. europaea. After 12 h of exposure, the survival rate of N. europaea treated with 1 mg L-1 Ag＋ was significantly lower than those treated with low （1 mg L-1） and middle concentrations （10 mg L-1） of AgNPs, but the survival rate in the treatment with high concentration （20 mg L-1） of AgNPs was much lower. Additionally, necrosis rates were higher in the treatment with 20 mg L-1 AgNPs. Electron microscopy showed that Ag＋ caused serious damage to the cell wall of N. europaea, disintegrated the nucleoids, and condensed next to the cell membrane; however, dissolved Ag＋ is only one of the antibacterial mechanisms of AgNPs.

关键词： ammonia-oxidizing bacterium cell necrosis cytotoxicity silver ions survival rate

Enhanced nonlinear optical absorption of Au/SiO_2 nano-composite thin films

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Chinese Physics B 2009年第12期18卷 5539-5543页

作者：赵翠华张波萍尚鹏鹏 school of Materials Science and engineering University of Science and Technology Beijing College of resources and environment Guangxi University

Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma sputtering. Au particles as perfect spheres with diameters between 10 nm and 30 nm are uniformly dispersed in the SiO2 matrix. Optical absorption peaks due to the surface plasmon resonance of Au particles are observed. The absorption property is enhanced with the increase of Au content, showing a maximum value in the films with 37 vol% Au. The absorption curves of the Au/SiO2 thin films with 3 vol% to 37 vol% Au accord well with the theoretical optical absorption spectra obtained from Mie resonance theory. Increasing Au content over 37 vol% results in the partial connection of Au particles, whereby the intensity of the absorption peak is weakened and ultimately replaced by the optical absorption of the bulk. The band gap decreases with Au content increasing from 3 vol% to 37 vol % but increases as Au content further increases.

关键词： Au/SiO2 nano-composite film plasma sputtering optical absorption spectra

Applicability of Artificial Recharge of Groundwater in the Yongding River Alluvial Fan in Beijing through Numerical Simulation

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Journal of Earth Science 2014年第3期25卷 575-586页

作者： Qichen Hao Jingli Shao Yali Cui Zhenhua Xie school of Water resources and environment China University of Geosciences Beijing Institute of Hydrogeology and engineering Geology

A groundwater transient flow model was developed to evaluate the applicability and effectiveness of artificial recharge scenarios in the middle-upper part of the Yongding River alluvial fan in Beijing. These scenarios were designed by taking into account different types of recharge facilities and their infiltration rate with the Middle Route Project for South-to-North Water Transfer（MRP） as the recharge water source. The simulation results suggest that：（1） the maximum amount of artificial recharge water, for scenario I, would be 127.42×106 m3 with surface infiltration facilities; and would be243.48×106 m3 for scenario II with surface infiltration and recharge wells under the constraint of the upper limit of groundwater;（2） with preferred pattern of recharge facilities, groundwater levels in both optimized recharge scenarios would not exceed the upper limit within the given recharge period; and（3implementation of the recharge scenarios would efficiently increase the aquifer replenishment and the groundwater budget will change from-54.11×106 to 70.89×104 and 183.36×104 m3, respectively. In addition, under these two scenarios groundwater level would rise up to 30 and 34 m, respectively, without increasing the amount of evaporation. The simulation results indicate that the proposed recharge scenarios are practically feasible, and artificial recharge can also contribute to an efficient recovery of groundwater storage in Beijing.

关键词： groundwater modeling artificial recharge infiltration rate groundwater management.

Acid Mine Drainage and Heavy Metal Pollution from Solid Waste in the Tongling Mines, China

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Acta Geologica Sinica(English Edition) 2008年第1期82卷 146-153页

作者： XUXiaochun XIE Qiaoqin CHEN Fang WANG Jun WU Wentao school of resources and environment engineering Hefei University of Technology Hefei 230009 China

Based on investigation of the characteristics of solid waste of two different mines, the Fenghuangshan copper mine and the Xinqiao pyrite mine in Tongling, Anhui province in central-east China, the possibility and the differences of acid mine drainage （AMD） of the railings and the waste rocks are discussed, and the modes of occurrence of heavy metal elements in the mine solid waste are also studied. The Fenghuangshan copper mine hardly produces AMD, whereas the Xinqiao pyrite mine does and there are also differences in the modes of occurrence of heavy metal elements in the railings. For the former, toxic heavy metals such as Cu, Pb, Zn, Cd, As and Hg exist mostly in the slag mode, as compared to the latter, where the deoxidization mode has a much higher content, indicating that large amounts minerals in the waste rocks have begun to oxidize at the earth surface. AMD is proved to promote the migration and spread of the heavy metals in mining waste rocks and lead to environmental pollution of the surroundings of the mine area.

关键词： acid mine drainage heavy metal pollution solid waste Tongling Anhui province China