Study on the Fractal Characteristics of Coal Body Fissure Development and the Law of Coalbed Methane Migration of around the Stope

Due to the complicated coalbed methane (CBM) occurrence conditions and the diverse geological structures in China, the promotion and application of the coal and gas simultaneous extraction technology have been seriously restricted. In view of this, this paper chooses Qingdong Coal Mine protection layer mining and CBM extraction field practice as the research background. Firstly, based on the similar material simulation experiment that simulates coal mining, the dynamic changing pattern of a mining field’s overburdened strata and corresponding stress are obtained, the relationship between gas desorption and stress can then be clarified. Further, with the help of the fractal theory and box counting method, the fracture development characteristics of the overlying strata are quantitatively described on the basis of experimental images. Finally, by building a model for calculating the penetrability coefficient of coal seam based on fractal dimension of mining fissure and analyzing the relationship between fissure development and fractal dimension, the gas migration law and the fissure development areas of #7 and #8 overburden strata where CBM concentrates can be revealed and determined. According to the orientation of the area mentioned above, the location of the CBM pumping field in relation to the coal seam roof and the arrangement of CBM extraction boreholes can be optimized, which make CBM extraction efficient. Meanwhile, the risk of coal and gas outburst is significantly reduced when the CBM concentration is controlled within 0.2% to 0.6% outside the corner of the working face and 0.1% to 0.35% in return flow, which is lower than 0.8%, the threshold of CBM concentration.

GEOMETRIC AND ELECTRONIC STRUCTURE OF HEAVY HIGHLY VISCOUS OIL COMPONENTS

Physical-chemical and structural-rheological properties of the oil disperse system are determined by the structure, size and composition of the complex structures resulting from the association of paraffins and tarry asphaltene components. Therefore, data about hydrocarbon composition, especially the structure of paraffins, tars and asphaltenes, required to choose recovery method in the extraction, field treatment, transportation and processing of heavy oils. In article parameters of the geometric and electronic structure of the tars and asphaltenes model molecules to determine reactivity indexes and, consequently, the possibility of a new oil dispersed system formation were calculated. Based on the density functional method B3LYP/6-311+G(d,p), quantum chemical calculations of the electronic structure and geometry of model tar molecules are given in the work. It was found that the number of benzene rings does not have a significant impact on the geometric and electronic structure of hydrocarbon fragments. The heteroatoms N, S and -OH functional group have a significant influence on the characteristics of model molecules. The nitrogen atom significantly increases the molecule dipole moment, compared to the sulfur and hydroxyl group, and the greatest change in geometric and electronic structure is observed in the presence of a sulfur atom. To choose recovery method in the heavy hydrocarbon crude treatment, the elemental composition is quite important, since it is heteroatoms in multi-core systems with condensed nuclei that affect the reactivity indices and provides generation of a free radical form and creation of a new oil dispersion system.

Optimization of Bioactive Substances in the Wastes of Some Selective Mediterranean Crops

Production of added products from industrial byproducts is a challenge for the current natural product industry and the extraction field more generally. Therefore, the aim of this study is to valorize the selected Mediterranean crops that can be applied as antioxidants, natural chelating agents, or even as biosolvents or biofuels after special treatment. In this study, the wastes of popular Mediterranean plants were extracted via homogenizer-assisted extraction (HAE) by applying response surface methodology (RSM) to examine the effects of process parameters on the total biophenolic contents (TBCs) of their residues. Box–Behnken design model equations calculated for each system were found significant (p < 0.0001) with an adequate value of determination coefficient (R2). Olive leaf had the highest TBC content (58.62 mg-GAE/g-DW with 0.1 g sample, 42.5% ethanol at 6522.2 rpm for 2 min), followed by mandarin peel (27.79 mg-GAE/g-DW with 0.1 g sample, 34.24% ethanol at 8772 rpm for 1.99 min), grapefruit peel (21.12 mg-GAE/g-DW with 0.1 g sample, 42.33% ethanol at 5000 rpm for 1.125 min) and lemon peel (16.89 mg-GAE/g-DW with 0.1 g sample, 33.62% ethanol at 5007 rpm for 1.282 min). The antioxidant activities of the extracts were measured by several in vitro studies. The most prominent biophenols of the wastes were quantified by high performance liquid chromatography (HPLC). Fourier-transform infrared-attenuated total reflectance (FTIR-ATR) and atomic force microscopy (AFM) techniques were also used for characterization.

Maximized Extraction of Flavonoid Luteolin from V.negundo L. Leaves: Optimization Using Box-Behnken Design

Background: Luteolin is a flavonoid unveiling various therapeutic activities, found in Vitex negundo L. Thus, there is a need to present process parameters at which maximum amount of luteolin can be extracted from V. negundo L. leaves in “one-run”. Objective: Response surface methodology (RSM) was employed for optimizing the process parameters for the extraction of luteolin from V. negundo L. leaves. The study also compared the efficacy of various traditional and modern extraction methods for luteolin extraction. Methods: Extraction conditions (solvent to drug ratio, extraction temperature and extraction time) were optimized by RSM, Box-Behnken Design (BBD). Quantification of luteolin in various extracts was done through High Performance Liquid Chromatography (HPLC). Results: Hot solvent extraction by reflux technique stood out to be the best technique and methanol was found to be the most effective solvent for luteolin extraction.Through the use of BBD, the optimal conditions for luteolin extraction were established as: solvent to drug ratio- 17.7 mL/g, extraction temperature- 55.5°C and extraction time-2.04 hours. Under such conditions 7.32 %w/w of luteolin was yielded which was close to predicted value of 7.29 %w/w. Conclusion: Reflux technique stood out to be the best among all the studied modes of extraction and methanol proved to be the most effective solvent. Moreover, all the three variables significantly affected the luteolin extraction. Our study shows the applicability of a statistical technique, RSM in phytocompound extraction field. This makes the optimization technique cheap and less laborious than the traditional optimization method.

Assessment of underground mining influences in the area of historic church building

The paper presents a case study of the influence of performed mining exploitation on a historic church building and provides a prediction of the effects of the planned exploitation. Due to properly designed and performed structural protections of the building, the exploitation without causing damages to the building’s structure was possible. The calculation results indicate that also the planned exploitation should not induce any structural damages to the building. The presented example exhibits the fact that exploitation is possible in areas of this type of buildings if adequate protections are applied and extraction field locations are correctly planned.

PROBLEMS OF EXPORT-IMPORT OPERATIONS ACCOUNTING IN UKRAINE'S EXTRACTION FIELD

The article develops a systematic approach to the management of mining, using, export and import non-metallic minerals for construction considering the economic parameters of the development of the world market situation and the domestic market. The analysis showed that the classification of minerals used by the Public Service Geology and Mineral Resources of Ukraine, the State Statistics Committee of Ukraine and Statistics of foreign economic activity - codes UKTZED - do not coincide that complicates the study process using these official sources. According to the results of the conducted researches, the indicators of the dynamics of minerals production in their natural and costly dimensions have been found to be inadequate. An analysis of dynamics and geographic structure of export-import operations was also conducted with natural sand, pebbles, gravel and breakstone. The obtained results allowed us to conclude that the approach to formation of export minerals' flows is not rational, because it poses a threat to the financial state of the mining industry and the country. An analysis of the geographical structure of the export and import of natural sand, pebbles, gravel and breakstone allowed proposing the use of a systematic approach to rational extraction, the use of the country's mineral resources base, while taking into account export-import flows and the price conditions of the external and internal markets and taking into account the resource component of state security.