Fracturing and thermal extraction optimization methods in enhanced geothermal systems

Fracture networks, fluid flow and heat extraction within fractures constitute pivotal aspects of enhanced geothermal system advancement. Conventional hydraulic fracturing in dry hot rock reservoirs typically requires high breakdown pressure and only produces a single major fracture morphology. Thus, it is imperative to explore better fracturing methods and consider more reasonable coupling mechanisms to improve the prediction efficiency. Cyclic fracturing using liquid nitrogen instead of water can generate more complex fracture networks and improve the fracturing performance. The simulation of fluid flow and heat transfer processes in the fracture network is crucial for an enhanced geothermal system, which requires a more comprehensive coupled thermo-hydro-mechanical-chemical model for matching, especially the characterization of coupling mechanism between the chemical and mechanical field. Based on the results of field engineering, laboratory experiments and numerical simulation, the optimum engineering scheme can be obtained by a multi-objective optimization and decision-making method. Furthermore, combining it with the deep-learning-based proxy model to achieve dynamic optimization with time is a meaningful future research direction.Document Type: PerspectiveCited as: Yang, R., Wang, Y., Song, G., Shi, Y. Fracturing and thermal extraction optimization methods in enhanced geothermal systems. Advances in Geo-Energy Research, 2023, 9(2): 136-140. https://doi.org/10.46690/ager.2023.08.0

Application of evolution-based uncertainty design on gear

The evolution of mechanical parameters, a factor affecting the mechanical reliability, has gathered more attention nowadays. However, studies on time varying uncertainty can hardly be found. A new method based on evolution-based uncertainty design (EBUD) is applied to the design of gear in this paper. Considering the wear evolution over the lifetime, a tooth wear’s time-varying uncertainty model based on the continuous-time model and Ito lemma is established. Drift and volatility functions dependent on the drift rate and volatility rate of rotational speed and torque are used to express the time-varying uncertainty of tooth thickness. The method can predict the reliability and provide an instruction in reliability improving, maintenance and repair of the gear system

STRENGTH ANALYSIS OF SCRAPER BUCKET BASED ON THE COUPLING OF HYPERMESH- EDEM-PATRAN

Bucket force is simplified as concentrated force or uniform force in traditional bucket strength analysis,which will result in inaccurate bucket strength analysis result. Taking Sandvik 1400 e scraper as an example in this paper,carrying out pretreatment on the bucket based on Hyper Mesh,simulating scraper working process by EDEM,it is obtained that bucket is characterized by complication and variable load during scraper operation. By way of coupling discrete element and finite element,bucket was loaded precisely,then bucket strength analysis and wear calculation were completed,which will provide theoretical basis for bucket structure optimization

Performance Analysis and Optimization of a 6-DOF Robotic Crusher

Considering the complexity of multidimension parameters and the mechanical performance of a 6-DOF robotic crusher, a multiobjective optimization function based on the transmission index and condition number is established. As an important operation in the screw theory, the reciprocal product between the transmission wrench screw of an actuator and the output twist screw of the mantle assembly is used to represent the instantaneous power. The expression of transmission index is derived according to the principle that constraint wrench screws apply no work to the mantle assembly. It can be used as a criterion to evaluate the transmission performance. Then, based on the Jacobian matrix, the equation of condition number is constructed which provides a criterion for evaluating kinematic accuracy. Finally, the workspace and singularity of the 6-DOF robotic crusher are analyzed to verify the rationality of the optimized variables. The results show that the optimized structure can completely crush the material in the workspace and effectively avoid singularity, which provides a basis for practical application

Prediction Model for Liner Wear Considering the Motion Characteristics of Material

A generic model to explore the relationship between the parameters of cone crusher and liner wear is provided in this paper. Relative slide and squeezing between material and liner are considered based on the operating conditions, structure parameters, and material properties. The sliding distance of the material under different conditions is discussed. It is detailed how operating parameters and structural parameters influence the pressure on the liner surface. Considering that the process of liner wear evolves over time, the updating method of the geometry of crushing chamber is adopted. The wear model is derived based on Archard theory and is calibrated with the measured wear profiles of the liner from a PYGB1821 cone crusher. Experiments show that the predicted wear amount is consistent with the measured results. The wear model can be used to predict the wear state of liner and quantify the influence of operating parameters and structural parameters on the liner wear

Influence of Operating Conditions and Crushing Chamber on Energy Consumption of Cone Crusher

This paper provides an energy consumption model and explains how the operating conditions and structural parameters of a crushing chamber affect energy consumption. Energy consumption is closely related to compressive pressure and displacement. The relationship between pressure, displacement and structural parameters is discussed. The influence of operating parameters on pressure and displacement based on the law of motion of material is examined. Energy consumption can be obtained by the product of pressure and displacement. In consideration of the pressure on the liner surface, which varies according to both height and circumference, an infinitesimal method was used to solve the issue of energy consumption. We validated the predicted energy consumption during breakage with experimental data from a PYGB1821 cone crusher which was consistent with the measured results. Finally, we provide an explanation of the influence of operating parameters and structural parameters on compressive pressure and displacement as well as energy consumption

The Protective Effects and Potential Mechanisms of Ligusticum chuanxiong: Focus on Anti-Inflammatory, Antioxidant, and Antiapoptotic Activities

Ligusticum chuanxiong (LC) is a Chinese materia medica which is widely used in clinical settings to treat headaches, blood extravasation, and arthritis. Recent studies demonstrate that LC possesses versatile pharmacological functions, including antiatherosclerosis, antimigraine, antiaging, and anticancer properties. Moreover, LC also shows protective effects in the progression of different diseases that damage somatic cells. Oxidative stress and inflammation, which can induce somatic cell apoptosis, are the main factors associated with an abundance of diseases, whose progresses can be reversed by LC. In order to comprehensively review the molecular mechanisms associated with the protective effects of LC, we collected and integrated all its related studies on the anti-inflammatory, antioxidant, and antiapoptotic effects. The results show that LC could exhibit the mentioned biological activities by modulating several signaling pathways, specifically the NF-κB, Nrf2, protein kinase, and caspase-3 pathways. In future investigations, the pharmacokinetic properties of bioactive compounds in LC and the signaling pathway modulation of LC could be focused

Original Article Peptic ulcer hemorrhage combined with acute gout: analyses of treatment in 136 cases

Abstract: This study aims to compare the safety and curative effect of celecoxib and small-dose methylprednisolone sodium succinate in patients with peptic ulcer hemorrhage combined with acute gout. In this randomized, controlled trial, a total of 136 patients with peptic ulcer hemorrhage combined with acute gout were divided into the celecoxib group or the small-dose methylprednisolone sodium succinate group. These patients underwent gastroscopy hemostasis and proton pump inhibitor (PPI) therapy. Moreover, for the treatment of gout, the patients were administered either celecoxib or small-dose methylprednisolone sodium succinate. Adverse reactions and the visual analogue scale (VAS) score were recorded for the two groups. The difference in adverse reactions between the two groups was not significant (χ 2 = 0.002, P = 0.967). The duration of evident pain relief after the first dose of treatment showed a significant difference between the two groups (t = 13.728, P < 0.01). The VAS scores before treatment were not significantly different between the two groups (t = -1.786, P = 0.076). The VAS scores at 6 h, 2 days, 4 days, 6 days, and 8 days after treatment were significantly different between the two groups (t = 3. 239, 6.586, 6.280, 3.737, 3.215; P = 0.002, 0.000, 0.000, 0.000, 0.002, respectively). In cases that receive effective gastroscopy hemostasis and PPI therapy, small-dose methylprednisolone sodium succinate exhibits a greater clinical curative effect for peptic ulcer hemorrhage combined with acute gout as compared to celecoxib, and is associated with greater safety