Informatics Publishing Limited

Shuai Gao ¹, Chen Chen ¹, Wei Wang ²

Affiliations
1 College of Construction Engineering, Jilin University, Changchun-130021, CN
2 Daqing Oilfield Production Engineering & Research Institute, Daqing-163000, CN

Abstract

At present, Most of the oil shale in-situ heating technology need to hydraulic fracturing in oil shale formation. Nearly all hydraulic fracturing is carried out after the casing perforation. Perforation parameters play an important role among hydraulic fracturing construction parameters, which even affect effect of oil shale in-situ heating. The hydraulic fracturing process of indoor physical simulation experiment is carried out with the same formation conditions and different perforation parameters. The effect of perforation diameter, perforation orientation (the angle between the direction of perforation and the direction of maximum horizontal stress) and perforation density to fracturing pressure and fracture propagation are researched. The experimental results show that fracturing pressure reduces with perforation diameter increasing, but the effect is not obvious. Fracturing pressure increases obviously with perforation orientation increasing, and fracture becomes more complex. Fracturing pressure decreases obviously with perforation density increasing, which has a very small impact on fracture propagation.

Keywords

Oil Shale, Hydraulic Fracturing, Perforation Parameters, Fracturing Pressure, Fracture Propagation.

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Wei Wang ¹, Chenchang Du ¹, Nengcheng Chen ¹, Zeqiang Chen ¹, Xian He ²

Affiliations
1 State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, 430079, CN
2 Dalian Academy of Reconnaissance and Mapping Co. Ltd., Dalian, 116061, CN

Abstract

This study evaluated the trace metal sources and their spatial distribution in surface sediments in Chaohu Lake, China, using multivariate statistical analysis and geostatistics. The results of the multivariate statistical analysis, including principal component analysis and cluster analysis, indicated that Cu, Pb and Zn were significantly influenced by anthropogenic sources, whereas, the remaining studied metals mainly originated from natural sources. Ordinary kriging was used to plot the spatial distribution of the trace metals and principal component scores, while indication kriging was applied to generate the probability of the trace metals exceeding their pollution threshold values. We found that natural origins and the grain size effect influenced the spatial distribution of Al, Cr, Fe, Mg, Ni, and V, while human sources combined with the former two factors affected the spatial distribution of Cu, Pb and Zn. The spatial distribution of each principal component scores represented the spatial impact of corresponding component on this lake. The possibility maps show that some areas had a high ecological risk caused by Cu, Pb and Zn. Multivariate statistical analysis and geostatistics are concluded to be effective tools to study trace metals.

Keywords

Trace Metals, Geostatistics, Semivariogram, Multivariate Statistics, Sediment.

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Mei Luo ¹, XiaoXian Zheng ¹, Wei Wang ²

Affiliations
1 Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing, CN
2 State Forestry Administration Survey Planning and Design Institute, Beijing, CN

Abstract

Studying the mechanisms between factors of stand structure and the environment is an important way to research and interpret the complex relationships between stand development and the environment. We investigated 113 sample plots of four typical forest types at Badaling forest farm in Beijing, and analysed stand soil structure, the correlations between stand structure and environmental factors, and the spatial distribution of soil nitrogen (TN) content and soil alkali-hydrolyzale (AN) content. The results showed that the typical forest types had significant differences in soil physical and chemical properties; the stand soil status of broad-leaved forest and scrubland was superior to that of the coniferous forest and the coniferous and broad-leaved mixed forest. The soil physical structure affected the stand structure more than the soil chemical structure, and stand structure variation caused by the soil factors was more important than the topographic factors in all the four typical forest types. Spatial heterogeneity in TN and AN was evidenced, and the overall N content was low.

Keywords

Correlation Analysis, Stand Structure, Typical Forests, Badaling Forests.

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Wei Wang ¹, Yajun Ye ²

Affiliations
1 College of History and Ethnic Culture , Guizhou University, Guiyang, Guizhou 550025, CN
2 College of History and Ethnic Culture , Guizhou University, Guiyang, Guizhou 550025, IN

Abstract

The rapid development of the agricultural industry has led to the excessive waste of agricultural resources and the serious destruction of the ecological environment. Agriculture is the basis of national livelihood and economic development, and agricultural ecological efficiency is an important indicator of a region’s agricultural productivity. Guizhou province of China is used as an example in this study to analyse the environmental pollution caused by the agricultural development process, quantitatively determine the agricultural ecological efficiency of a region, and propose measures to improve agricultural ecological efficiency. This study summarizes the development status of natural resources, environmental pollution etc. of agro-ecosystem in Guizhou province, and establishes the agricultural ecological efficiency evaluation indicator system. The agricultural ecosystem panel data of Guizhou province from 2005 to 2015 are also obtained. The data envelopment analysis-Malmquist model is used to calculate the agricultural ecological efficiency of Guizhou province from two levels, i.e., year and city, and the improvement measures for agricultural ecological efficiency are proposed. Results show that the agricultural ecological efficiency of Guizhou province is in the medium development level and increases by 7% on average. Technological progress is the most important factor of the growth of agricultural ecological efficiency. However, comprehensive technical efficiency decrease, and the decrease in scale efficiency are the main factors that cause the reduction in comprehensive efficiency level. The total factor productivity of all the cities in Guizhou province is greater than 1; among the cities, Liupanshui City reaches the highest growth rate, i.e., 12%. The results of this study possess a positive reference value for the adjustment of the agricultural ecosystem structure and the improvement of the agricultural ecological environment level. The findings may also serve as a basis for the enhancement of the comprehensive agricultural sustainable development and the alleviation of the serious destruction of the ecological environment caused by the rapid development of the agricultural industry.

Keywords

Agricultural Ecological, Efficiency, Improvement Measures, Guizhou Province.

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Wei Yang ¹, Haijin Zhou ¹, Fuqi Si ¹, Cheng Liu ², Wei Wang ¹, Youwen Sun ¹, Wenqing Liu ², Changgong Shan ²

Affiliations
1 Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Science, Hefei 230031, CN
2 University of Science and Technology of China, Hefei 230026, CN

Abstract

A bibliometric approach is used in this study for the assessment of greenhouse gas (GHG) research trends on a global scale. The relevant literature published from 2000 to 2014 in journals of all subject categories of the Science Citation Index Expanded from the Web of Science Core Collection databases has been used. The strings ‘greenhouse gas*’ or ‘green house gas*’ are used for retrieving data. The information of GHG research-related literature is analysed, including the types and languages of literature, characteristics of articles published, source countries/territories of articles, distribution of articles in different subject categories and journals, frequency/number of words in the title of articles and the frequency/number of keywords used. Over the past 15 years, an obvious growth trend is seen in the number of published articles, and countries/territories involved in the study of GHG. The number of the world articles published by the seven most developed industrialized countries (G7) is maximum in the field of GHG research. The G7 countries have played a predominant role in GHG research in the last 15 years. Analysis of the title words, author keywords and keywords plus showed that ‘greenhouse gas emission’ and ‘climate change’ were the keywords with highest frequency during the whole research period. Carbon sequestration and biotechnology have been widely used in reducing the environmental pressure of the greenhouse effect and the dependence on fossil energy.

Keywords

Bibliometric Analysis, Climate Change, Global Trends, Greenhouse Gas Research, SCI.

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Deyong Wang ¹, Wei Wang ¹

Affiliations
1 School of Information Engineering, PingDingShan University, CN

Abstract

To monitor the operation of coal mine safety production, an online learning method of fault identification for coal mine safety production through video probabilistic appearance manifolds is proposed in this paper. For a category of the coal mine equipment safety state, a common representation of the normal appearances of this category would usually be learned off-line. From video monitoring of this category, an appearance model can be learned online through a prior generic model and successive video. The further details, as well as both the normal and abnormal appearances, can be expressed as an appearance manifold. In our algorithm, an appearance manifold would be approximately estimated by a series of sub-manifolds, and each sub-manifold is further refined into a low-dimensional linear sub-space. Thus, the time required for image recognition is reduced to meet the demands of real-time image processing. Through experimental analysis, we can demonstrate that our online learning algorithm method is an efficient method for video-based image recognition, and its application in coal mine safety production has proven to be very effective.

Keywords

Probabilistic Appearance Manifolds, Online Learning, Image Recognition, Coal Mine.

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Xinjian Wang ¹, Wei Wang ²

Affiliations
1 North China University of Water Resources and Electric Power, Zhengzhou, 450011, IN
2 Henan Geology and Mineral Construction Engineering Group Co LTD, Zhengzhou, 450007, IN

Abstract

With groundwater temperature, hybrid-genetic algorithm is employed to locate multi-passage concentrated seepage underground to increase the probability of optimal global solutions, calculation efficiency and precision. The parameters of concentrated seepage passages (CSPs) indicated initially by the previous optimization and attraction basins of modified temperature residuals are evaluated again by the proposed full parameter optimization. The smaller CSP impacts on the stronger are eliminated, since all the parameters associated with all the CSPs are calculated by the last one-off optimization. In this case, three optimization steps are implemented with crossover fractions of 0.8, 0.5 and 0.45 (0.3), and the modified resultant residuals are 13.441, 2.27 and 0.7 individually. Results of this method are more effective compared to those from other methods and actual applications.

Keywords

Abutment, Dam Safety, Hybrid-Genetic Algorithm, Geothermal Temperature, Seepage.

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