18 research outputs found
Study on Movement Law of Overlying Strata during Shallow Thinner Seam Mining in Shendong Mining Area
No full textGiven the particularity and the first time for shallow thinner seam mining in Shendong mining area, the overlying strata movement law during shallow thinner coal seam mining has been studied in this paper based on the fully mechanized thinner coal face of NO.71301 in Shi Getai coal mine, resorting to observation on spot, numerical simulation and other methods. Through research, the important laws and features had been obtained, such as, initial pressure step, periodical pressure step, the obvious partition of periodical weighting, the unitary elasticity distribution of front abutment pressure, and the stress shell morphology over the mining rock, which provides important characteristic for roof control and foundation for the powered support selection.</jats:p
Research on fully mechanized mining equipment removal planning during sequencing working face
No full textThe current fully mechanized mining equipment removal plan during sequencing working face mainly depends on manual preparation. The large workload and low efficiency lead to the extension of the construction period. The quick removal mainly depends on a high degree of mechanized operations. There is little research on optimizing the fully mechanized mining equipment removal plan during sequencing working face between different mines or different working faces in the same mine. In order to solve this problem, by investigating the mining conditions of Shendong Group's fully mechanized mining equipment in recent three years, the key parameters such as working face, equipment, personnel, and time are defined, which characterize the fully mechanized mining equipment removal during sequencing working face. Taking minimizing the maximum completion time as the objective function, a mathematical model for the fully mechanized mining equipment removal planning during sequencing working face is established. A genetic algorithm is designed to solve the mathematical model. The three-segment coding method considering the selection of working face, fully mechanized mining equipment and construction team is adopted, and the fitness function is built. The chromosomes of working face, fully mechanized mining equipment and construction team are selected, crossed and mutated. Considering the latest mining time, the legitimacy of chromosomes is judged and adjusted. By setting the number of iterations, search process of the algorithm is terminated and outputs the results. Based on the genetic algorithm for the fully mechanized mining equipment removal planning during sequencing working face, a management system of the fully mechanized mining equipment removal plan during sequencing working face based on B/S architecture is developed. It has realized the functions of basic information management of fully mechanized working face removal during sequence working face, and fully mechanized mining equipment removal planning during sequencing working face. The example shows that the application of genetic algorithm can shorten the construction period of fully mechanized mining equipment removal of 11 fully mechanized working faces in Shendong Group in 2021 from 103 days to 91 days. The method effectively improves the fully mechanized mining equipment removal planning efficiency and engineering efficiency
Analysis on the dynamic error for optoelectronic scanning coordinate measurement network
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An Angle Precision Evaluation Method of Rotary Laser Scanning Measurement Systems with a High-Precision Turntable
No full textRotary laser scanning measurement systems, such as the workshop measurement positioning system (wMPS), play critical roles in manufacturing industries. The wMPS realizes coordinate measurement through the intersection of multiple rotating fanned lasers. The measurement model of multi-laser plane intersection poses challenges in terms of accurately evaluating the system, making it difficult to establish a standardized evaluation method. The traditional evaluation method is based on horizontal and vertical angles derived from scanning angles, which are the direct observation of wMPS. However, the horizontal- and vertical-angle-based methods ignore the assembly errors of fanned laser devices and mechanical shafts. These errors introduce calculation errors and affect the accuracy of angle measurement evaluation. This work proposes a performance evaluation method for the scanning angle independent of the assembly errors above. The transmitter of the wMPS is installed on a high-precision turntable that provides the angle reference. The coordinates of enhanced reference points (ERP) distributed in the calibration space are measured by the laser tracker multilateration method. Then, the spatial relationship between the transmitter and the turntable is reconstructed based on the high-precision turntable and the good rotational repeatability of the transmitter. The simulation was carried out to validate the proposed method. We also studied the effect of fanned laser devices and shaft assembly errors on horizontal and vertical angles. Subsequently, the calibration results were validated by comparing the residuals with those derived from the space-resection method. Furthermore, the method was also validated by comparing the reference and scanning angles. The results show that the maximum angle measurement error was approximately 2.79″, while the average angle measurement error was approximately 1.26″. The uncertainty (k = 1) of the scanning angle was approximately 1.7″. Finally, the coordinate measurement test was carried out to verify the proposed method by laser tracker. The results show that the average re-scanning error was 2.17″
Application of a self-compensation mechanism to a rotary-laser scanning measurement system
No full textImprovement of Low-Fertility Soils from a Coal Mining Subsidence Area by Immobilized Nitrogen-Fixing Bacteria
No full textCoal mining subsidence leads to reductions in soil fertility. In order to improve soil physical and chemical properties and to promote vegetation restoration, a nitrogen-fixing bacterium named S1 was isolated from the coal mining subsidence area in the Shendong mining area, and a zeolite-immobilized nitrogen-fixing bacterium was studied to improve the soil in the subsidence area. The results show that the immobilized nitrogen-fixing bacteria can significantly improve the ammonium nitrogen and nitrate nitrogen of soil by 50 times and 0.6 times, respectively, at 20 days, and it can also improve organic matter. In pot experiments, it was found that immobilized microorganisms can improve germination rate, plant height and the dry and fresh weight of maize. The results of the above soil culture tests and pot experiments were then compared and analyzed. It was found that plants made obvious use of soil ammonium nitrogen and nitrate nitrogen, and planting the plants was conducive to increases in soil organic matter
Dietary disodium fumarate supplementation alleviates subacute ruminal acidosis (SARA)-induced liver damage by inhibiting pyroptosis via mitophagy-NLRP3 inflammasome pathway in lactating Hu sheep
Full text linkLiver damage is common in ruminants with subacute ruminal acidosis (SARA). Disodium fumarate (DF) could regulate rumen microbial community and neutralize ruminal organic acids. This study aimed to evaluate the effect of dietary DF supplementation on SARA-induced liver damage and investigate the underlying mechanism. The results showed that feeding a high-concentrate diet induced decreased rumen fluid pH and increased ruminal LPS. The rumen fluid pH in the HC group was less than 5.6 at 4 time points, indicating that SARA was successfully induced. The histopathological analysis showed that in the HC group, hemorrhage and inflammatory cell infiltration were observed in liver tissue. Using ELISA kits and biochemical analyzer, we identified that the contents of interleukin 1beta (IL-1β), interleukin 18 (IL-18), caspase-1, and the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in hepatic vein were elevated in the HC group. However, DF supplementation increased rumen fluid pH value, decreased ruminal LPS, attenuated hemorrhage and inflammatory cell infiltration in the liver tissue, and decreased contents of IL-1β, IL-18, caspase-1, AST, and ALT in the hepatic vein. Real-time PCR and western blot analysis displayed that SARA-induced increased expression of pyroptosis-related proteins (GSDMD-NT) was attenuated in the HCDF group. Meanwhile, SARA induced increased expression of mitophagy and inflammasome-related proteins (MAP1LC3-II, PINK1, Parkin, cleaved-caspase-11, cleaved-caspase-1, NLRP3, and ASC) and elevated expression of inflammasome-related genes (NLRP3, CASP1, and ASC), which was reversed by DF supplementation. Moreover, SARA activated toll-like receptor 4 (TLR4)-nuclear factor kappa B (NF-κB) signaling pathway and inhibited the entry of forkhead box A2 (FOXA2) into the nucleus, which was reversed by DF supplementation. Collectively, our data suggest that dietary DF supplementation inhibited hepatocyte pyroptosis by regulating the mitophagy-NLRP3 inflammasome pathway and the NF-κB signaling pathway, thus alleviating SARA-induced liver damage in Hu sheep
The research on calibration methods of dual-CCD laser three-dimensional human face scanning system
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