Journal of Mechatronics and Artificial Intelligence in Engineering
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Experimental analysis of the process of purifying transformer oil from various impurities under the influence of a constant electric field and assessment of mathematically modeled results
Get PDFThis paper has examined the cleaning of transformer oil by using electricity field on a theoretical and practical basis. Scientific analysis was done on the physicochemical characteristics of the oil and the effects of impurities on the electrical insulation characteristics of oil. A mathematical model explaining the movement of impurities under the action of an electric field was constructed on the basis of which, the extent of oil purification was established. According to the carried out theoretical and practical studies, the efficiency of transformer oil purification by constant electric field was tested. Based on the findings of theoretical modeling, the level of oil extraction against mechanical impurities is 40, and the electrical strength of the oil is enhanced by 16 and based on the findings of experiments that are carried out under laboratory conditions, the electrical strength is enhanced by 21. Due to the comparison between theoretical and practical outcomes, the deviation of the electrical strength indicator of the oil does not exceed 5 % and this fact supports the validity of the theoretical model developed. It was also determined that the purification process is affected by environmental factors like temperature, humidity, strength of electric field and composition of the oil. Enhancing oil purified in constant electric field is one of the effective solutions to the enhancement of the reliability of transformers and their service life
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
Scientific and practical substantiation of transient processes in asynchronous electric motors of mainline electric locomotives
Get PDFThe research work focuses on scientifically substantiating the operating conditions of small and medium-power auxiliary asynchronous electric motors used in mainline electric locomotives under JSC “Uzbekistan Railways”. The aim is to provide a scientific basis for the operational efficiency of auxiliary asynchronous electric motors and, based on the research findings, to conduct a practical investigation of their service life. This, in turn, will enable timely maintenance of auxiliary asynchronous electric motors in locomotives. Additionally, it will contribute to improving the performance indicators of auxiliary asynchronous electric motors
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
Vibration velocity control of compound wedge-shaped excavation blasting in tunnels under complex environments
Get PDFThis paper explores the optimization of cutout schemes in tunnel excavation and blasting by introducing an improved segmented wedge-shaped blasting method, validated through both numerical simulations and field tests. The numerical simulations use the ANSYS/LS-DYNA fluid-solid coupling algorithm to analyze the damage effects, effective stress distribution, and vibration characteristics of surrounding rock for both the Conventional wedge cut and the segmented wedge cut methods. The results show that segmented wedge cutting significantly enhances the utilization rate of blast holes, reduces the formation of large gravel fragments, and effectively mitigates surrounding rock vibration velocities. In comparison to the Conventional method, the optimized undercut scheme not only increases blasting efficiency but also greatly enhances the rock fragmentation in the undercut area, thereby ensuring tunnel construction safety. The field test results validate the accuracy of the numerical simulations and show that the enhanced scheme holds significant potential for practical application in real-world projects
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
Investigation of transient processes in auxiliary asynchronous electric motors of locomotives using differential equations
Get PDFThe aim of this research is to scientifically substantiate the operating conditions of small and medium-power auxiliary asynchronous electric motors currently in use on mainline electric locomotives of the VL60, VL80, and Ermak 3ES5K types. The goal is to draw conclusions based on scientific research, such as evaluating the operational efficiency of auxiliary asynchronous electric motors and creating the possibility to predict their service life based on the assessment results. This, in turn, will enable timely maintenance of auxiliary engines in locomotives
Theoretical assessment of the mechanical properties of fiber concrete using the dispersion analysis method
Get PDFThis paper examines how the type of fiber and the amount of fiber in concrete impacts the mechanical characteristics of fiber-reinforced concrete (FRC) by both experimental testing and statistical modelling. Basalt, polypropylene, and steel fiber reinforced concrete specimen were cast at different percent ratios (0, 0.1, 0.2 and 0.3) and subjected to laboratory conditions to measure compressive strength. At every dose and fiber type, three specimens were tested, and average values of the strengths were computed. OriginPro was used to fit the data in polynomial regression models (second degree) to quantify the connections between the parameters of this fiber and compressive strength. The most important statistical indicators provided in the assessment of the model accuracy were coefficients of determination (R2), adjusted R2, F-statistics, p-values, and residual analysis. The results revealed that the models were all characterized by high predictive accuracies (R2= 0.72, 0.93) and found to be significant using ANOVA (p< 0.0001). Results validated that the type of fiber along with the dosage were critical in the effectiveness of strength with optimal amount enhancing performance and loads beyond or below those levels decreasing the matrix bonding. The produced models offer a predictive predicting model that would be helpful in FRC mixture optimization. The study presents significant information in the field of structural engineering where a newly established structure will be needed to have superior durability, dependability, and load capacity
Study of a two-stage wood chip hydrolysis process and the kinetics of monosaccharide formation
Get PDFThis article studies the sulfuric acid hydrolysis of paulownia and poplar wood chips using a two-stage approach. The research analyzes the temperature-dependent kinetics of the hydrolysis process, nothing a peak yield of reducing agents at 170 °C. An increased likelihood of reducing agent decomposition is observed as temperature rises, especially at 180 °C. Using liquid chromatography, the amounts of glucose, fructose, and arabinose in the hydrolysates were measured, with the largest glucose yield obtained at 170 °C. In addition, High-performance liquid chromatography (HPLC) and Fourier-transform infrared (FTIR) spectroscopy showed the emergence of new functional groups in the hydrolyzed wood structure. Based on mathematical modeling and experimental validation, the two-stage hydrolysis method is regarded as a good technique. This method helps raise the of hydrolysates, which are employed as raw materials in biopolymer manufacture
Application of unsupervised identification of dissolved gases in transformer oil based on spin coating film making process
Get PDFAddressing the issues of low efficiency and uneven collection of dissolved gases in transformer oil leading to overfitting and poor performance of identification models, we propose a novel film-making process that integrates Gaussian process and unsupervised pre-classification to enhance the recognition efficiency of dissolved gases in transformer oil. This method not only forms a thinner and more uniform separation layer, significantly improving degassing performance and collection efficiency, but also addresses the problems of insufficient data labeling and sample imbalance by introducing the K-means++ clustering algorithm and pseudo-random integration technology, thereby enhancing model robustness and generalization ability. Moreover, the designed Gaussian Process Multi-Classification (GPMC) method employs probabilistic interpretation for result presentation, which increases the accuracy of fault identification. Experimental results show that under consistent starting conditions, the RCC and ARI indicators of our pre-classification method are close to 0.8, with the test set’s recognition rate exceeding 80 %, while the GPMC method misclassified only 2.4 % of the cases in the 1800-case dataset. These improvements make our method particularly effective for handling uncertainties and imbalances in dissolved gas cases in transformer oil, showcasing its potential for practical applications