Abstract: During the molten salt flow process in the molten salt control valve, localized temperatures may fall below the solidification point of the molten salt, leading to partial solidification within the valve body and consequently affecting the flow performance of the valve. This study conducts temperature and flow field simulations under various operating conditions to investigate the potential occurrence of solidification during the molten salt flow process. Specifically, it analyzes whether the molten salt temperature drops below its solidification point under three extreme scenarios: fully open valve position, sudden valve closure with residual molten salt remaining in the valve body, and abrupt flow interruption due to pipeline equipment failure. The research findings demonstrate that molten salt solidification does not occur in any of these three scenarios, providing valuable reference data for subsequent optimization design of molten salt control valves. Read More

Abstract: With the rapid development of electronic devices toward miniaturization, low power consumption, and high integration, power management integrated circuits (PMICs), as the "energy hub" of electronic systems, have a significant impact on the energy efficiency, reliability, and battery life of end devices. This paper examines the core design and practical applications of PMICs. First, it identifies the key technical requirements for PMICs in different scenarios. It then conducts an in-depth analysis of implementation paths for topology design, energy efficiency optimization techniques, reliability protection, and electromagnetic compatibility (EMC) optimization. The feasibility of these technologies is verified by integrating mass production solutions from manufacturers such as Texas Instruments and Infineon. At the application level, this paper focuses on practical cases of PMICs in consumer electronics, new energy, industrial control, and automotive electronics. Finally, it summarizes the challenges currently faced by PMIC design, such as wide-bandgap semiconductor adaptation and high-integration heat dissipation, and looks forward to the development trend of intelligent and highly integrated PMICs. This research demonstrates that PMIC design must be guided by scenario requirements, achieving a balance between energy efficiency, reliability, and cost through the coordinated efforts of multiple technologies. Its expanded application will further promote the greener and more efficient development of the electronic information industry and the new energy sector. Read More

Abstract: Self-lubricating epoxy (EP) composites and coatings are required in bearings, gears, and structural tribo-components that must operate with low friction and stable wear across dry, boundary, mixed, and corrosion-coupled environments. The uploaded literature converges on three synergistic strategies: solid-lubricant nanofillers and hybrids (graphite/graphene/GO, h-BN, MXene, ZnS–GO) that form robust transfer films and provide thermal/electrical pathways; encapsulated and vascular lubrication that releases liquids on demand; and fiber/architected reinforcements (carbon fabrics, filament winding, substrate engineering) that deliver load-bearing capacity and anisotropic transport. This review synthesizes mechanisms and trends strictly from the uploaded sources, embeds research-style tables summarizing systems, processes, test contexts, and outcomes, and discusses open issues around dispersion and interfacial bonding, film stability under heat and shear, corrosion–tribology coupling, dosing/triggering in on-demand lubrication, test comparability, and manufacturing scale-up. We conclude with future directions emphasizing multi-scale hybridization, adaptive lubrication networks (capsule+vascular), thermal/anti-corrosion co-design, oriented architectures, and application-driven substrate/process choices for water-lubricated and oscillatory bearings. Read More

Abstract: Hardness is a crucial property and indicator of materials, representing their ability to resist the penetration of hard objects into their surface. Particularly in rock mechanics, rock hardness not only serves as a measure of the difficulty in fracturing rocks but is also closely related to rock drillability (i.e., the resistance of rocks to drilling), compressive strength, drill bit selection, drilling efficiency, and rock fragmentation methods. Therefore, in the field of mechanical drilling, the accurate determination of rock hardness becomes critically important. With the advancement of science and technology, humanity has progressively deepened its understanding and research on rock hardness, leading to the invention of various instruments for measuring it. Industrial development has gradually phased out primitive measurement methods such as scratching and scoring, making rock hardness measurements increasingly accurate and steering the process onto a scientific track. This investigation, from the perspective of rock hardness, delves deeply into this significant mechanical property, examines the domestic and international background of rock hardness measurement techniques, summarizes the instruments, tools, methods, principles, and characteristics of rock hardness measurement, and offers insights into the future development prospects of rock hardness measurement. Read More

Abstract: Since the introduction of PDC bits in 1973, significant advancements have been achieved in drilling efficiency. However, to address the diverse requirements of various formation rocks—such as differences in hardness, strong abrasiveness, and heterogeneity—and to further enhance drilling performance, several companies worldwide have continuously improved upon conventional cylindrical PDC cutters. These efforts have led to the development of a series of innovative geometric designs for novel-shaped PDC cutters. This paper focuses on an investigation of non-planar cutters. It begins by introducing the application background of non-planar cutters and analyzing the current research status and development trends related to non-planar cutters and the rock-breaking mechanisms of PDC, both domestically and internationally. Furthermore, various types of non-planar cutters are enumerated, and their characteristics are described in detail. Regarding the research methodology for non-planar PDC cutters, this paper elaborates on the procedural steps—from the analysis of the rock-breaking mechanism of PDC cutters, to the evaluation of their rock-cutting performance, and finally to experimental analysis. This systematic approach provides valuable guidance for the rational design of non-planar PDC cutters. Read More

Abstract: This paper addresses the accuracy bottleneck in torque monitoring for workover rig rotary tables, presenting a systematic analysis of the dynamic composition of torque, static influencing factors, and the characteristics of dynamic inertia. By establishing a torque balance equation, the coupling mechanisms among pipe string friction, mechanical transmission losses, and inertial torque are quantitatively revealed. The study specifically investigates the nonlinear effects of well inclination, dogleg severity, and cuttings bed thickness on frictional torque, as well as the degradation patterns of mechanical transmission efficiency due to clutch wear and braking modes. The results indicate that significant reduction in frictional torque can be achieved by: controlling the well inclination within the applicable range for conventional directional wells, optimizing trajectory design to suppress bending stress in sections with high dogleg severity, and real-time regulation of drilling parameters to maintain a cuttings bed thickness of less than 5 mm. Concurrently, clutch wear must be strictly controlled within a 0.5 mm threshold, and electromagnetic braking mode can effectively suppress torque fluctuations and mitigate impact loads. This research provides a theoretical foundation and technical support for the development of high-robustness, non-contact torque monitoring systems. Read More

Abstract: Yak dung has both fuel and ecological value in the plateau areas of China. However, the existing collection methods have problems such as being easily crushed or consuming a large amount of manpower. To this end, this paper designs a semi-mechanized hand-guided yak manure picking vehicle, with a focus on optimizing the picking mechanism. By constructing design variables and constraints, using Matlab to calculate key parameters, and conducting motion analysis based on SolidWorks, the picking efficiency is improved and the labor intensity is reduced. Read More

Abstract: As one of the ceramic matrix composites (CMCs), carbon fiber-reinforced silicon carbide matrix (Cf/SiC) composites have become ideal materials for various engineering applications due to their outstanding properties. Precision surface grinding technology has been widely applied in the machining of CMC composites; however, the material removal mechanism of Cf/SiC composites remains incompletely elucidated. To reveal the material removal mechanism during the grinding of Cf/SiC composites, we designed and conducted single-abrasive scratch tests. Experimental parameters, particularly cutting speed, were aligned with actual grinding processes. Results indicate that grinding parameters—feed rate, cutting depth, and cutting direction—significantly influence grinding force and surface integrity. Impact at the tool tip and abrasive action are the primary causes of material removal. During the grinding of Cf/SiC composites, the predominant material removal mode is brittle fracture. This is because the damage behavior of Cf/SiC composites is primarily a combined manifestation of matrix cracking, fiber fracture, and fiber/matrix interface debonding. These findings are rationally explained based on the material properties and microstructural damage characteristics of the composites. Read More

Abstract: The optimisation of liquid hydrostatic spindle structural configurations and parameters constitutes a primary factor influencing the load-bearing capacity, oil film stiffness, and fluid temperature rise during high-speed cutting operations in gear shaping machines. To achieve high rigidity and precision while mitigating friction-induced temperature rise, advanced research is required into the influence of lubricant viscosity-temperature characteristics on the oil film properties of fluid dynamic spindles. Specifically, high-speed gear shaping machines exhibit an eccentric oil film effect in fluid dynamic bearings during high-speed cutting operations. Consequently, accurately investigating the motion patterns and characteristics of the radial surface in liquid-static spindles during practical theoretical design and engineering trials, while accounting for the impact of fluid temperature rise on cutting precision, remains a persistent research challenge. Read More

Abstract: Spiral bevel gears are critical high-precision transmission components widely used in demanding fields such as automotive and aerospace. Their performance is fundamentally determined by advanced machining technology and the precision design of cutting tools. This paper provides a comprehensive review of the historical evolution, current status, and future trends in spiral bevel gear manufacturing. It systematically outlines the development trajectory of machining technology, from early mechanical machines to modern fully computer numerical control (CNC) systems, exemplified by Gleason's Phoenix series, and highlights China's progress in achieving technological independence. The review then focuses on the design of cutting tool edges, a key factor influencing tooth surface quality. It analyzes research on edge geometry—from traditional straight edges to advanced curved profiles—aimed at optimizing contact patterns and reducing transmission error. The analysis reveals that while significant advancements have been made, mainstream designs often simplify edge geometry. Consequently, the future direction points toward deeper integration of intelligent, closed-loop manufacturing systems and a shift in tool design philosophy: from passive "form-following" to active "form-creating." This entails designing complex edge geometries based on conjugate surface principles and multi-physics simulations, performed in synergy with optimized process parameters and machine tool dynamics. The integration of digital twins, artificial intelligence, and additive-subtractive hybrid manufacturing is identified as the pathway to achieving next-generation gears with superior performance, precision, and reliability. Read More

Abstract: High temperatures underground can cause demagnetization in the hollow permanent magnet motor of the intelligent well electric control sliding sleeve, affecting the motor's output performance. To address this issue, this paper establishes a finite element simulation model for the motor and, through comparative analysis, selects the outer rotor type hollow permanent magnet motor solution. Environmental temperature and motor structure are the main factors affecting the performance and demagnetization of the intelligent well electric control sliding sleeve permanent magnet motor. Using Taguchi methods and simulation experimental data, the motor structure is optimized. The optimized motor parameter combination is a slot opening width of 2mm, an air gap of 0.3mm, a pole arc coefficient of 0.76, and a permanent magnet thickness of 3.1mm. After optimization, the motor torque increased by 17.219%, the cogging torque decreased by 27.521%, the demagnetization rate decreased by 55.223%, and the efficiency decreased by only 0.149%. After optimization, the torque difference of the motor increased, the motor's working capacity improved, the torque ripple rate also increased, and its stability decreased slightly, but still within an acceptable range. Read More

Abstract: This paper focuses on the multi-dimensional health state assessment of complex mechanical equipment, using a fracturing pump as a case study. It proposes a comprehensive assessment framework that integrates the analysis of multiple data dimensions, including real-time operational data, vibration data, and historical maintenance data. A health baseline is constructed by obtaining residual data of the equipment in a healthy state using a Generalized Regression Neural Network (GRNN) and extracting time-frequency domain features. The health assessment model for the vibration data dimension is built by calculating and normalizing the Mahalanobis Distance between the vibration data to be assessed and the health baseline. An equipment operational state evaluation model based on multiple characteristic parameters is established, using these parameters as failure criteria, to quantitatively characterize the Health Index from the real-time operational data dimension. Based on reliability theory, a multi-state transition probability for the main components of the equipment is obtained using a Markov model. The probability is mapped to the Health Index using a weighted average method for defuzzification, thereby constructing a health assessment model for the historical maintenance data dimension. Finally, the health state of the equipment is graded and comprehensively evaluated. This method can provide theoretical support for the preventive maintenance and health management of equipment, while also offering a reference for the intelligent operation and maintenance of complex mechanical equipment. Read More

Abstract: Resilience, as a comprehensive evaluation concept, assesses the overall post-event response capability of a system, providing theoretical foundations and decision support for system design optimization and disaster emergency management. Extreme marine environments characterized by violent winds, strong currents, and large waves significantly increase the failure probability of deepwater drilling riser systems. These extreme loads induce excessive stress, fatigue, and fracture, heightening the risk of structural failure. This paper proposes a resilience assessment method for drilling risers under extreme sea conditions. The method first employs high-precision hydrodynamic simulation to fit and process acquired time-varying load data, deriving riser failure probabilities. It then quantifies degradation processes using a dynamic Bayesian network model. Subsequently, a dynamic recovery process encompassing fault diagnosis, resource allocation, and maintenance models is established. Two metrics—failure rate and recovery capability—are selected as single-stage resilience indicators for each process, with resilience calculated using the area method. Using a drilling riser in the South China Sea as a case study, the proposed resilience framework demonstrates validity and applicability. Results confirm the method effectively quantifies riser performance degradation and recovery capacity, providing critical guidance for engineering design and operational management. Read More