Maintenance, Reliability and Condition Monitoring
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Study on the interaction state between polymer modifiers and asphalt based on precise grinding
Get PDFTo clarify the impact of resin modifier fineness on the performance and interaction of modified asphalt, this study selects resin modifiers to prepare modified asphalts. The effects of the fineness parameters of resin modifiers on the road performance of modified asphalts are investigated. The segregation tests and Han curves are employed to analyze the influence of modifier on the compatibility of modified asphalt. The scanning electron microscopy is utilized to characterize the interaction between resin modifiers and asphalt. The results indicate that resin modifiers improve the high-temperature performance and deformation resistance of asphalt binder but lead to the adverse effect on low-temperature performance. Adjusting the particle size of the modifier could improve the modification effect of resin modifiers on asphalt binder
An integrative review of control strategies in robotics
Get PDFThis paper presents an integrative review of control strategies in robotics, covering classical control methods (linear quadratic regulator, proportional-integral-derivative), modern methods (adaptive, sliding mode, model predictive, and H-infinity), intelligent control methods (neural network, fuzzy logic, and machine learning), and hybrid control methods (integration of classical, modern, and intelligent control methods) to identify the advantages, limitations and gaps for future. A brief comparison of control methods between the types of control strategies is conducted with respect to robustness, stability, and complexity of implementation on 3 different levels of evaluation criteria: high, average, and low; advantages; limitations; and robotic applications, including examples. This paper discusses the theoretical and practical advancements and the classification of control strategies according to controller types (linear, nonlinear, and learning-based), approaches (model-based and model-free), and classifications (centralized, decentralized, and modal control). The review highlights the strengths, limitations, and potential research directions in bridging classical, modern, intelligent, and hybrid control paradigms to achieve safe, efficient, and adaptive robotic behavior in complex, uncertain environments. We discuss the future direction: autonomy, human-robot collaboration, and enhanced learning and challenges: cost, reliability, safety of control strategies, concluding with recommendations for future research
The effect of Cranial Postural Balance (CPB) appliance on re-establishing mandible and body posture in an adult patient. Case report
Get PDFThis case report intends to present a functional appliance designed by the first author, that follow the principles expected for all functional appliances. It is not anchored on teeth. It does not produce mechanical forces and uses tongue and mandible posture change as natural forces. The appliance was used for 24 months, only to sleep. The patient came complaining discomfort with improper occlusion of the teeth and temporomandibular pain. Body balance was evaluated by DIERS and was also altered. It was possible to find out the presence of a unilateral crossbite and alteration on condyle position inside the cavity evaluated by CBCT. After the treatment with CPB (Cranial Posture Balance) appliance associated with osteopathic procedures, the occlusion and the temporomandibular complains were improved
The influence of robots on the spatial electric field measurement for zero value insulator recognition
Get PDFZero value insulators pose a threat to the safe and stable operation of transmission lines. By walking with tracked robots, the local electric field distribution of insulator strings can be quickly detected and measured, thereby identifying zero value pieces. To clarify the influence of robot architecture on the electric field measurement of insulator strings and propose a fast identification criterion for zero-value recognition, this paper establishes a true model of 220 kV insulator strings and an equivalent model of robots. The electric field distribution characteristics of the robot structure working on insulator strings were analyzed through finite element simulation, and the influence of factors such as robot material and size on local electric field distortion characteristics was studied, especially the local electric field variation laws under zero and non-zero values. The model's validity is confirmed through relevant simulations, ensuring its reliability for practical applications. Further detailed simulation analysis was conducted on the local electric field distortion characteristics of the robot architecture at different positions of the insulator string, and the electric field measurement characteristics of the zero value insulator were obtained. Based on the simulation results of the 220 kV insulator string, a criterion for measuring and identifying zero value insulators for 500 kV was proposed and applied to 500 kV. The research results reveal the influence of electric field detection and measurement robots on local electric field distortion of zero value insulators, which can provide technical support for intelligent operation and maintenance of external insulation in power transmission and distribution
MIMO radar river flow measurement based on space-velocity-time algorithm and adaptive correction model
Get PDFAccurate measurement of river hydrological characteristics is critical for assessing the impacts of flooding caused by meteorological and geomorphological factors. Flow velocity are key indicators in hydrological monitoring. Traditional measurement approaches, such as continuous-wave Doppler radar and pulsed radar systems, are typically mounted on bridges or fixed supports and offer only single-point measurements. These methods often suffer from limited detection range, low accuracy, and poor resistance to environmental interference. To address these limitations, this study proposes a three-dimensional flow detection framework based on multi-input multi-output (MIMO) radar sensors. By leveraging the high reliability and interference resistance of MIMO radar, along with a Space-Velocity-Time (SVT) algorithm that incorporates spatiotemporal information (two-dimensional surface velocity and time), the proposed method enables robust 3D river flow monitoring. In this study, comparative experiments were conducted on four rivers in China with different flow conditions, geomorphic features and weather environments. Results demonstrate that the proposed method achieves a measurement error of less than 5 % compared to acoustic Doppler current profilers (ADCP) and other conventional mechanical approaches, while also offering improved safety and real-time performance. Moreover, an adaptive flow correction algorithm is presented, which uses three optimized prediction models to compute the correction factor and reduces the mean streamflow measurement error to 0.79 % after correction, providing an effective solution for river gauging, flood control and flood resilience
Improving the quality of cast blanks by applying force to the solidifying metal
Get PDFIn the course of the research, the authors studied the formation of structures of cast blanks on various alloys, depending on the conditions of metal crystallization, including under the influence of vibration. An analysis of the structures of the control samples (blanks) confirmed that solidification under normal conditions occurs mainly according to the sequential crystallization scheme, as evidenced by the width of the structural zones in them. The external vibration effect on solidifying alloys leads to a significant change in the conditions of their crystallization, in particular, to a significant grinding of the macrostructure of the workpieces and a change in the size of the structural zones, which indicates a volume-sequential scheme of their crystallization. It is established that vibration increases the physico-mechanical properties of cast metal and significantly reduces their anisotropy over the section of the workpieces
Design of a multifunctional UAV based on composite materials: integration of vacuum infusion, CFD analysis, and intelligent energy management
Get PDFThis study proposes an integrated design approach for a multifunctional UAV using composite materials, combining vacuum infusion, CFD-based aerodynamic analysis, and an STM32-based energy management system. CFD results showed a lift coefficient CL= 0.812, drag coefficient CD= 0.055, and L/D= 14.7, representing a 28 % improvement over aluminum structures. FEM analysis indicated a maximum stress of 312.4 MPa with a safety factor of 1.12, while vacuum infusion achieved 98.7 % resin impregnation, enhancing stiffness by 28 % and reducing weight by 25 %. The automated energy management system increased energy efficiency by 16.3 %, extending flight duration and improving operational stability
Exercita Rim – physical exercise protocol with blood flow restriction for people with chronic kidney disease on conservative treatment
Get PDFPhysical exercise promotes benefits for people with chronic kidney disease, but little has been investigated on the effects of strength training using the blood flow restriction method. The objective is to present the intervention protocol with strength physical exercise associated with the RFS method for people with stage 3 CKD and to report the benefits in the hemodynamic scope and personal satisfaction after 4 weeks of exposure to physical exercise. The study is an intervention protocol proposed to be developed over 12 weeks, with 9 exercises, in people with CKD-3, on 3 days a week lasting 50 minutes. The participants were divided into groups with low load, with high load and group with blood flow restriction and hemodynamic variables (blood pressure and heart rate) and affective satisfaction in relation to the proposed exercise were measured. Forty people aged 58±8.9 years were recruited, of which 30 participated in the intervention. Regarding satisfaction, the high-load group presented better results (2.8 to 3.5) (p= 0.035); and for blood pressure, the blood flow restriction group showed significance in systolic pressure (p= 0.034). It is concluded that after 4 weeks of intervention with a strength training protocol aimed at blood flow restriction, there are trends of improvements in systolic blood pressure levels, and affective sensations were improved after the end of the exercise sessions
Research on the temperature system of an evaporator based on Smith-VUF PID
Get PDFTemperature serves as a critical process parameter in industrial systems, directly influencing reaction kinetics, product quality, and operational efficiency. The variation of temperature can affect reaction rate, product quality, and impurity generation, directly impacting production efficiency and product performance. However, due to the nonlinearity of temperature control systems, traditional controllers cannot meet design requirements, particularly in scenarios demanding high - temperature control accuracy, it is difficult for them to achieve a small deviation range. Therefore, this study focuses on the evaporator as the controlled object and conducts modeling, simulation analysis, and control strategy research on the evaporator temperature control system. It establishes the Smith-variable universe fuzzy PID(Smith-VUF-PID) temperature control system and deploys control strategies, solving issues such as large overshoot and inadequate control accuracy often encountered with traditional methods
Study on the impact of wheel roundness defects on axle fatigue damage
Get PDFWith the continuous increase in the operating mileage of China’s high-speed railway network, wheel out-of-roundness has become increasingly common in electric multiple unit (EMU) vehicles. Wheel out-of-roundness directly increases the vibration level of the axle, affects various vehicle components, and in severe cases, may lead to fatigue fracture of the axle – a key load-bearing component – thereby causing major safety incidents. To investigate the influence of wheel out-of-roundness on axle dynamic stress and to evaluate the fatigue strength of the axle under such conditions, this study analyzes the effects of different wheel flat lengths, polygon orders and depths, as well as various operating speeds on the dynamic stress of EMU axles. Based on numerical simulation results, the fatigue damage of the axle under wheel out-of-round conditions and the impact of wheel polygonal wear over one development cycle are calculated. The findings show that within a single re-profiling cycle, wheel flats shorter than 50 mm have a negligible effect on axle fatigue damage. Furthermore, a reference limit for polygonal wear depth is proposed, providing theoretical guidance for wheel maintenance and safety assessment of EMU vehicles