Fractional Differential Equations in the Exploration of Geological and Mineral Construction

As the geological exploration data is relatively sparse, unevenly distributed, and contains many geological faults, simple geological surface reconstruction has certain limitations. Based on the fractional differential equations, the paper establishes a subsidence prediction model in exploring geological and mineral resources. The dynamic system described by the reaction-diffusion equation can be mapped to a nonlinear cellular network through space and time discretization. At the same time, the original partial differential equations can be transformed into ordinary differential equations. Furthermore, we can use the difference method to simulate its evolutionary behavior quantitatively. The research results show that the error accuracy between the prediction results of the fractional gray theory established in this paper and the actual engineering results is higher

Defect Detection for Metal Shaft Surfaces Based on an Improved YOLOv5 Algorithm and Transfer Learning

To address the problem of low efficiency for manual detection in the defect detection field for metal shafts, we propose a deep learning defect detection method based on the improved YOLOv5 algorithm. First, we add a Convolutional Block Attention Module (CBAM) mechanism layer to the last layer of the backbone network to improve the feature extraction capability. Second, the neck network introduces the Bi-directional Feature Pyramid Network (BiFPN) module to replace the original Path-Aggregation Network (PAN) structure and enhance the multi-scale feature fusion. Finally, we use transfer learning to pre-train the model and improve the generalization ability of the model. The experimental results show that the method achieves an average accuracy of 93.6% mAP and a detection speed of 16.7 FPS for defect detection on the dataset, which can identify metal shaft surface defects quickly and accurately, and is of reference significance for practical industrial applications

Study on the Structure and Related Parameters of Underwater Ozone Generator

AbstractIn order to control eutrophication for water body better, underwater ozone generator has been developed by electro- hydraulic power impulse technology. By one that in a pair of electrodes was designed as hollow structure, the charge and discharge circuit of the device and the structure of the electric chamber were analyzed. And not only the optimal related electrical parameters, such as voltage, frequency of discharge and electric capacity, but also the best parameters of electrodes and the structure of electric chamber have been established. The result shows that the processes of product ozone and purify water are all complete in water by underwater ozone generator based on electro-hydraulic power impulse technology. The related parameters of the device which have been established have provided a basis for improving the efficiency of ozone generation & water treatment and applicability of the ozone generator

Study on the disturbance effect of pulsating flow and heat transfer in self-excited oscillation shear layer

The fluid movement motion has an important influence on the evolution of the pul¬sating flow in the hot runner. Using the large eddy simulation numerical method, the instantaneous velocity, wall shear stress, boundary-layer thickness, and Nusselt number of hot runner section under different structural parameters at an inlet pressure of 5000 Pa were studied. The research results showed that the backflow vortex can be formed in the hot runner, and the fluid at the axis center of hot runner can form a pulsating flow under the squeezing action of the backflow vortex. The pulsating flow had a strong disturbance effect on the fluid around the axis center and accelerated the heat exchange between the fluid around the axis center and the wall. The disturbance effect of pulsating flow gradually strengthened with the flow of the main flow to the downstream. When d2/d1 was 1-1.8, the wall shear stress first increased and then decreased, and the wall heat transfer efficiency first increased and then decreased. The maximum wall shear stress was 36.4 Pa. When L/D was 0.45-0.65, the boundary-layer thickness first decreased and then increased, and the heat transfer efficiency first increased and then decreased. The minimum boundary-layer thickness was 0.392 mm and the maximum Nusselt number was 138. When d2/d1=1.4 and L/D=0.55, the maximum comprehensive evaluation factor reached 1.241, and the heat transfer efficiency was increased by 24.1%

Calibration and Validation of Flow Parameters of Irregular Gravel Particles Based on the Multi-Response Concept

The discrete element method (DEM) often uses the angle of repose to study the microscopic parameters of particles. This paper proposes a multi-objective optimization method combining realistic modeling of particles and image analysis to calibrate gravel parameters, after obtaining the actual static angle of repose (αAoR_S) and dynamic angle of repose (βAoR_D) of the particles by physical tests. The design variables were obtained by Latin hypercube sampling (LHS), and the radial basis function (RBF) surrogate model was used to establish the relationship between the objective function and the design variables. The optimized design of the non-dominated sorting genetic algorithm II (NSGA-II) with the actual angle of repose measurements was used to optimize the design to obtain the best combination of parameters. Finally, the parameter set was validated by a hollow cylinder test, and the relative error between the validation test and the optimized simulation results was only 3.26%. The validation result indicates that the method can be reliably applied to the calibration process of the flow parameters of irregular gravel particles. The development of solid–liquid two-phase flow and the wear behavior of centrifugal pumps were investigated using the parameter set. The results show that the increase in cumulative tangential contact forces inside the volute of centrifugal pumps makes it the component most likely to develop wear behavior. The results also illustrate the significant meaning of the accurate application of the discrete element method for improving the efficient production of industrial scenarios

Effects of prometryn on oxidative stress, immune response and apoptosis in the hepatopancreas of Eriocheir sinensis (Crustacea: Decapoda)

Prometryn, a triazine pesticide product used to control weed growth, poses a high risk to aquatic organisms in the environment. Several toxicological evaluations have been performed on bony fish and shrimp exposed to prometryn. However, there have been no reports conducted on the toxic mechanism of prometryn with regard to Eriocheir sinensis. In this study, our research evaluated the toxic effects of prometryn via in vitro and in vivo toxicity tests on E. sinensis. Firstly, we estimated the exposure toxicity of prometryn to E. sinensis, and then we constructed a 6 h transcriptional profile and conducted an enrichment analysis. To further reveal the toxicity of prometryn, the hepatopancreas (hepatopancreatic cells) was analyzed for antioxidant, immune and lipid-metabolism-related enzymes, antioxidant- and apoptosis-related gene expression, histopathology and TUNEL. From the results, we determined that the 96 h-LD50 was 70.059 mg/kg, and using RNA-seq, we identified 933 differentially expressed genes (DEGs), which were mainly enriched in the amino and fatty acid metabolism and the cell-fate-determination-related signaling pathway. The results of the biochemical assays showed that prometryn could significantly decrease the activities/levels of CAT, SOD, GSH, AKP and ACP, reduce the levels of T-AOC, TG, TCH, C3 and C4, and increase the MDA content. In addition, the expression levels of Nrf2, GSTs and HO-1 were first upregulated and then downregulated with increasing time. Histopathology showed that prometryn damaged the structure of the hepatopancreas cells and induced apoptosis, suggesting that the PI3K–Akt signaling pathway may be involved in the damage process of hepatopancreas cells (PI3K, PDK and Akt were downregulated whereas Bax was upregulated), leading to their apoptosis. The above results indicated that prometryn could cause injury of the hepatopancreas through oxidative stress, induce cell apoptosis, disrupt the lipid metabolism and cause immune damage. This study provided useful data for understanding and evaluating the toxicity of prometryn to aquatic crustacea

Effects of Prometryn Exposure on Hepatopancreas Oxidative Stress and Intestinal Flora in <i>Eriocheir sinensis</i> (Crustacea: Decapoda)

There is growing evidence that long-term exposure to prometryn (a widely used herbicide) can induce toxicity in bony fish and shrimp. Our previous study demonstrated its 96 h acute toxicity on the crab Eriocheir sinensis. However, studies on whether longer exposure to prometryn with a lower dose induces toxicity in E. sinensis are scarce. Therefore, we conducted a 20 d exposure experiment to investigate its effects on the hepatopancreas and intestine of E. sinensi. Prometryn reduce the activities of antioxidant enzymes, increase the level of lipid peroxidation and cause oxidative stress. Moreover, long-term exposure resulted in immune and detoxification fatigue, while short-term exposure to prometryn could upregulate the expression of genes related to immunity, inflammation and detoxification. Prometryn altered the morphological structure of the hepatopancreas (swollen lumen) and intestine (shorter intestinal villi, thinner muscle layer and thicker peritrophic membrane). In addition, prometryn changed the species composition of the intestinal flora. In particular, Bacteroidota and Proteobacteria showed a dose-dependent decrease accompanied by a dose-dependent increase in Firmicutes at the phylum level. At the genus level, all exposure groups significantly increased the abundance of Zoogloea and a Firmicutes bacterium ZOR0006, but decreased Shewanella abundance. Interestingly, Pearson correlation analysis indicated a potential association between differential flora and hepatopancreatic disorder. Phenotypic abundance analysis indicated that changes in the gut flora decreased the intestinal organ’s resistance to stress and increased the potential for opportunistic infection. In summary, our research provides new insights into the prevention and defense strategies in response to external adverse environments and contributes to the sustainable development of E. sinensis culture

Polyculture Affects the Growth, Antioxidant Status, Nutrient Content, and Flavor of Chinese Mitten Crabs (<i>Eriocheir sinensis</i>) and Largemouth Bass (<i>Micropterus salmoides</i>)

Chinese mitten crabs (Eriocheir sinensis) and largemouth bass (Micropterus salmoides) are popular with consumers in China. In recent years, the polyculture of these two species has received more attention, but little is known about how their interactions affect their commercially important traits. In this study, we set up an E. sinensis monoculture group (EM), a M. salmoides monoculture group (MM), and a polyculture group containing both species (EP) and compared the growth parameters, antioxidant statuses, nutritional compositions, and flavor qualities of crabs and fish between the different culture modes. Growth parameters in male crabs and largemouth bass were significantly higher in the EP group than in the EM and MM groups, respectively. Crabs in the EM and EP groups did not differ significantly in malondialdehyde content or glutathione peroxidase activity, regardless of the sampling time, which suggests that crabs in these groups had similar antioxidant and immunity capacities. Compared to the MM group, the activities of superoxide dismutase and catalase of largemouth bass in the EP group were higher, indicating the superior antioxidant capacity of fish in the polyculture mode. Alkaline phosphatase and acid phosphatase activities of both crabs and largemouth bass fluctuated with time in all groups, indicating their important roles in maintaining the health of these cultured species. The amino acid and fatty acid contents of edible tissues were similar between the EM and EP groups and the MM and EP groups, suggesting comparable flavor and quality of edible tissues in crabs and largemouth bass between culture modes. This study provides theoretical support for the polyculture of Chinese mitten crabs and largemouth bass