Abstract: After a period of use, automobiles require lubricant replacement to ensure engine reliability. However, the main components of waste oil(wo) remain unspoiled. Researching their regeneration is crucial for environmental protection and sustainable energy development. This study utilized isopropanol as a flocculant and zeolite as an adsorbent to recycle waste lubricants. A comparison of the tribological, rheological, and compositional properties of the regenerated oil (RO) with fresh oil (FO) revealed that the former exhibits shear thinning, enhancing its friction-reducing effect. The optimal load for the RO is 140N, where the friction coefficient is 0.8833, and wear volume is 21% lower than that of FO. Read More

Abstract: This study investigates the anchoring capacity issues pertaining to internally-fitted inserted tooth slips within 140-grade casing pipes. By conducting static analysis, a formula linking tooth stress to tooth diameter, tooth inclination angles (both frontal and rear), and the base inclination angle has been formulated. Utilizing orthogonal testing and finite element simulations, the structural parameters of segmented toothed slips were refined. The findings reveal that by setting the tooth diameter at 7mm, the base wedge angle at 18°, the tooth groove angle at 55°, the tooth height at 6.5mm, and the circumferential angle at 8°, there is a notable enhancement in the evenness of stress distribution between the teeth and casing, resulting in a more balanced anchoring effect. Read More

Abstract: In this experiment, silver nanoball@ graphene nanosheets (SG) composite additive using under a current-carrying was prepared via in-situ reduction method, which has both good electrical conductivity and tribological properties. The conductivity test results showed a 12-fold increase in the conductivity of the novel composite compared to the pure ionic liquid LP108. Without the current carrying, the values of COF were decreased to 0.070 and the wear volume of the disk was reduced by 88.4% at an additive concentration of 0.10 wt%. when a 1A current was applied to both ends of the friction pair,the average COF of the lubricant material was as low as 0.06892 with a 78.6% reduction in wear. This is because the movement of anions and cations in the ionic liquid can be accelerated by the electric current, and Ag and C elements in the additive can be adsorbed on the surface of the friction pair to form a protective film. This research result opens up a new way to improve the tribological properties of sliding electrical contacts from micro and nano scale technology and to develop a new generation of highly conductive lubricant materials. Read More

Abstract: With the intensifying trend of global population aging, the demand for health monitoring among the elderly is becoming increasingly urgent. This paper addresses the issues of bulkiness and complexity in traditional health monitoring devices by proposing a portable health monitoring system based on STM32 embedded technology. The system utilizes the MAX30102 photoplethysmography (PPG) sensor to achieve non-invasive heart rate and blood oxygen saturation (SpO₂) detection. An optimized signal processing algorithm effectively eliminates motion artifacts, while the STM32F103C8T6 microcontroller facilitates data acquisition and real-time analysis. Compared to conventional medical equipment, this system is compact, energy-efficient, and user-friendly, offering a reliable technological solution for daily health monitoring and chronic disease management in the elderly. It holds significant application value in the field of smart elderly care. Read More

Abstract: This study investigates the influence of arc transition oil cavity structure on the load-bearing characteristics of hydrostatic oil films in high-speed gear hobbing machine spindles under high-stroke conditions. By establishing fluid simulation models of oil cavity structures with different arc radii (r=0.5, 1.0, 1.5, and 2.0 mm), the effects of parameters such as eccentricity and stroke speed on oil film pressure and shear force distribution were systematically analyzed. The results demonstrate that the arc transition oil cavity structure significantly enhances the load-bearing capacity and lubrication performance of the hydrostatic oil film. Specifically, the structure with an arc radius of r=2.0 mm exhibits the most uniform pressure distribution, the lowest maximum pressure and shear force, and optimal performance. While eccentricity has a minor impact on pressure distribution, increasing eccentricity raises pressure on the eccentric side and slightly reduces it on the opposite side. At an eccentricity of 0.5, slight shear force concentration occurs on the eccentric side. Under high stroke speeds (1.0–2.0 m/s), both oil film pressure and shear force increase with speed, but the r=2.0 mm cavity structure remains the most stable, with no significant expansion of shear force concentration zones. Optimizing the oil cavity structure and employing higher supply pressure effectively improves the lubrication performance and operational stability of the hydrostatic spindle, providing theoretical and practical guidance for the design of high-speed gear hobbing machine spindles. Read More

Abstract: The paper investigates the effect of vibration on compressive strength and cementitious strength of cement stone through experiments, analyzes the effect of different vibration parameters on the macroscopic mechanical properties of cement, and microscopically, it is observed by electron microscope to verify the effect of vibration on cement stone to improve the internal structure of cement stone, and the experimental results show that vibration is able to significantly improve the compressive strength and cementitious strength of cement stone. Within a certain range, with the increase of vibration frequency and time, the compressive strength gradually increases, while the cement strength shows a trend of increasing first and then stabilizing. It is found that vibration can promote a more uniform distribution of cement particles, reduce the number and size of pores, vibration 20Hz, 40Hz and 60Hz compared with the porosity of static cement reduced by 23.14%, 39.72% and 50.79%, improving the compactness of cement stone. Guidelines are provided for the selection of optimal vibration parameters for vibratory cementing tool operations. Read More

Abstract: To address the issue that the ultra-precision positioning device in the form of piezoelectric ceramic actuated flexible hinge can only be positioned in a single direction, a three-degree-of-freedom nano-positioning platform is proposed. Firstly, the structural designs of the flexible hinge guiding mechanism and the flexible hinge transmission amplification mechanism are conducted, and then the overall structural model of the three-degree-of-freedom nano-positioning platform is designed. Through the static and dynamic modeling, analysis and verification of the bridge amplification mechanism, a theoretical basis is provided for the design of the bridge amplification mechanism. Subsequently, the dynamic platform is simulated, analyzed and verified using ANSYS Workbench to further validate the rationality of the design. Read More

Abstract: This study addresses the demand for high-precision, large-stroke positioning in fields such as ultra-precision manufacturing, optical systems, and micro-nano positioning. A novel micro-nano positioning platform based on flexure hinges and a bridge-type amplification mechanism is proposed. The platform utilizes piezoelectric ceramics for actuation, with the bridge-type amplification mechanism amplifying the displacement. Theoretical analysis, parameter optimization, and finite element simulations were conducted to evaluate the system's performance. The design includes the selection of flexure hinges, development of guiding mechanisms, and analysis of the platform's static, dynamic, and kinematic performance. Results demonstrate that the platform achieves high-resolution, large-stroke positioning, meeting the application requirements of objective lens positioning and other high-precision scenarios. This study employs a piezoelectric objective positioning platform based on a bridge-type amplification mechanism. The platform utilizes piezoelectric ceramics as the driving force and compensates for the small displacement of piezoelectric ceramics through a bridge-type amplification mechanism. It integrates arc-shaped flexure hinges and a symmetric multi-link flexure guiding mechanism to ensure high-precision and decoupled displacement transmission. The platform is compactly designed with dimensions of 70mm × 55mm, achieving a maximum stroke of 0.2mm and a positioning accuracy of 5nm, meeting the requirements for objective lens positioning while accommodating certain load-bearing capabilities. Read More

Abstract: In this paper, a deflecton stage, actuated by piezoelectric ceramics actuator and capable of rotating along both the X and Y axes via a Hooke-type flexible hinge mechanism, is meticulously designed. Utilizing three-dimensional modeling software, the flexible mechanism of the piezoelectric deflection stage is modeled in detail. Furthermore, ANSYS software is employed to conduct a finite element analysis (FEA) on the flexible hinge mechanism component of the piezoelectric deflection stage, focusing on characteristics such as stroke, load capacity, stiffness, and Modal and other properties. The analysis reveals that the deflection angles can achieve up to 3.32 mrad and 3.34 mrad respectively, while the first-order natural frequency stands at 385.93 Hz. These specifications adequately fulfill the stringent requirements of high-speed operation for a large-stroke deflection stage. Read More

Abstract: Course-based ideological and political education, as a key measure to implement the Party's educational policy and fulfill the fundamental task of fostering virtue and nurturing talent in the new era, aims to incorporate value guidance into the main channel of professional course teaching. Deeply integrating the concept of fostering virtue and nurturing talent into the classroom can help students build a solid moral foundation and shape a correct scientific value system. The teaching content of computer software courses is relatively narrow, mainly focusing on technical aspects, with relatively insufficient attention paid to the moral value aspect. Therefore, under the guidance of the course-based ideological and political education concept, professional teachers need to take professional knowledge as the carrier, closely combine with the core values of the times, and organically integrate ideological and political elements into the entire teaching process. Through this approach, the deep integration of professional knowledge imparting and value cultivation can be achieved, reaching the goal of all-round education in engineering professional courses and helping students grow into high-quality talents with both professional technical literacy and moral sentiments. Read More