Journal of Engineering and Thermal Sciences
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Numerical simulation of the deformation behavior of a composite foundation consisting of rubber particle loess-CFG under dynamic loading
Get PDFThe CFG pile technology is primarily employed for foundation reinforcement, offering cost-saving benefits and demonstrating significant reinforcement effects. Consequently, it has gained widespread utilization. However, due to its unique composition and exceptional strength characteristics, investigating the dynamic properties of rubber particle loess-CFG poses significant challenges. In this study, a numerical simulation approach is employed to investigate the dynamic characteristics of rubber particle loess-CFG and its deformation response under dynamic loading is analyzed. The results indicate that the deformation of rubber particle loess-CFG remains minimal under static loading, while it significantly increases under dynamic loading. However, the vertical and horizontal displacements at the top of the mattress layer are comparatively smaller than those observed in loess-CFG, highlighting their seismic stability. The mattress layer of the rubber particle loess-CFG undergoes vertical compression and deformation, while being horizontally squeezed towards the central region. The horizontal displacement and its variation range are significantly greater than that of the entire pile and the soil between piles. Therefore, it is crucial to analyze the material properties, thickness, and extent of the mattress layer during design in order to mitigate its influence. When subjected to dynamic loading at the base of the model, the rubber particle loess-CFG exhibits a strip distribution of vertical displacement which gradually decreases from bottom to top. Moreover, as focal depth increases, the impact of dynamic loading on foundation deformation diminishes. Consequently, rubber particle loess-CFG provides a dual functionality of enhancing foundation strength while effectively resisting dynamic deformations. These research findings provide a theoretical basis for designing reinforced foundations using rubber particle loess-CFG and offer an innovative approach for recycling waste tire rubber particles
A simple harmonic quantum oscillator: fractionalization and solution
Get PDFA quantum mechanical system that mimics the behavior of a classical harmonic oscillator in the quantum domain is called a simple harmonic quantum oscillator. The time-independent Schrödinger equation describes the quantum harmonic oscillator, and its eigenstates are quantized energy values that correspond to various energy levels. In this work, we first fractionalize the time-independent Schrödinger equation, and then we solve the generated problem with the use of the Adomian decomposition approach. It has been shown that fractional quantum harmonic oscillators can be handled effectively using the proposed approach, and their behavior can then be better understood. The effectiveness of the method is validated by a number of numerical comparisons
Contributions of jaw functional orthopedics in temporomandibular joint ankylosis (TMA) – clinical case report
Get PDFTemporomandibular joint (TMJ) ankylosis is one of the most disabling pathological conditions that can occur in the maxillofacial region, often occurring at an early age, limiting growth and causing facial deformity, which significantly affects the quality of life of the individual. The objective of the study was to evaluate the contribution of Jaw Functional Orthopedics (JFO) in TMJ ankylosis after the surgical phase. The case of a 7-year-old female patient diagnosed with bilateral condylar ankylosis (fibrous ankylosis on the right side and bony ankylosis on the left side) is presented. On clinical examination, facial asymmetry, retrognathia, muscle contraction and opening limitation were observed. Treatment consisted of temporalis muscle flap rotation surgery with condylectomy and coronoidectomy, physical therapy, and functional therapy with OFM. The clinical results at 4 months of follow-up suggest significant progress in oral opening and protrusion. The patient showed a high degree of satisfaction with the results obtained. She is currently continuing with the use of orthopedic appliances to correct the sequelae of ankylosis and improve mandibular kinematics
Active suspension LQR control based on modified differential evolutionary algorithm optimization
Get PDFThe selection of weight matrices Q and R in the LQR control strategy for active suspension is susceptible to subjective interference. To address this issue, a modified differential evolutionary algorithm is proposed to optimize the active suspension LQR controller, ensuring that the weighting coefficients are set to their optimal values. The differential evolutionary algorithm exhibits drawbacks in terms of its slow convergence rate and the significant impact of algorithm parameter settings on the obtained results. An modified differential evolutionary algorithm that is adaptive to the two candidate mutation strategies and adaptively adjusts the scaling factor and crossover rate is proposed so as to better improve the ability of jumping out of the local optimum and global search. The algorithm's functionality is verified by constructing a 1/4 suspension model in the Simulink software platform and implementing a modified differential evolution algorithm program written in C++ language using MATLAB. The program iterates through Simulink inputs to obtain the optimal fitness value for three suspension comfort indices. By comparing the results with those obtained from passive suspension and traditional LQR control of active suspension, optimizing the LQR control of active suspension based on the modified differential evolution algorithm can effectively reduce vehicle vibration amplitude while considering overall suspension performance enhancement, thereby significantly improving ride comfort and handling stability
Research on the launch dynamics characteristics of Gatling guns
Get PDFThe advantages of the Gatling gun, such as high firing rate, large interception range, and wide range of use, have made it an indispensable weapon system in the defense field. At present, the analysis of shooting vibration of the Gatling gun is a challenging key point in related research. In response to the lack of research on the shooting vibration characteristics of Gatling gun weapon systems, this paper carries out a numerical simulation study of the launch dynamic characteristics of the Gatling gun based on the nonlinear launch dynamics theory of artillery. The results of muzzle disturbance under continuous shooting conditions are obtained, and the shooting density of Gatling guns under different situations is analyzed and compared based on the method of shooting density calculation. This research fills the gap in the study of launch dynamics of Gatling weapons, providing design references and theoretical support for the overall design and performance verification of Gatling guns
Optimizing mechanical properties of virgin and recycled PLA components using Anova and neural networks
Get PDFThe increasing demand for polymers in additive manufacturing (AM) has led to a significant increase in plastic waste, with over 300 million metric tons used in recent years. This research article explores the use of Poly Lactic Acid (PLA) as a biodegradable thermoplastic recycled material for 3D printed components, comparing its properties with virgin PLA and discussing solutions for variation and mechanical features improvement. Fused Deposition Modeling (FDM) is a widely used additive manufacturing process that allows for the creation of three-dimensional objects by depositing molten material layer by layer. This study investigates the impact of infill density, layer thickness, and raster angle for recycled 3D printing material, focusing on their dimensions and their influence on processing efficiency. This research paper aims to investigate the mechanical effects of recycled 3d printed components which are printed by using FDM with the combination of different process parameters compared with virgin PLA. From results optimal process parameters are found to enhancing quality and performance of recycled 3D printed components. Later results are compared by Analysis of Variance (ANOVA) as a statistical tool and also with ANN technique, which minimizes error deviation
Determination of kinematic and dynamic characteristics of a reversible vibratory conveyor with an electromagnetic drive
Get PDFThe paper considers the design parameters that must be provided during the practical implementation of small-sized reversible vibratory conveyors with an electromagnetic drive. The proposed conveyor is developed on the basis of a classical two-mass oscillatory system. Two oscillating masses are connected by symmetrically assembled round-shaped rods. In order to avoid angular (torsional) oscillations of the vibratory conveyor, the geometrical centers of mass and stiffness of the spring system are aligned at the same point. The analysis of kinematic characteristics is performed by means of numerical solving of the system of nonlinear Lagrange-Maxwell differential equations. The influence of the phase shift angle between the electromagnetic excitation of horizontal and vertical oscillations on the trajectories of the mass center of the conveying member is analyzed. The first two frequencies and forms of natural oscillations of the vibratory conveyor are determined for estimating its dynamic characteristics. The novelty of this study lies in the development of a new design of a vibratory conveyor with a controllable independent electromagnetic drive that provides the conveying reversibility and efficiency
Method of experimental determination of the effective area of a pneumatic spring of high-speed rolling stock
Get PDFThe object of research is a pneumatic spring of high-speed rolling stock of the railway. The method of experimental static testing of a pneumatic spring of high-speed rolling stock is presented. Based on experimental tests, the “force-strain” dependences of a pneumatic spring are obtained when the pressure gauge in the pneumatic spring changes from 2.5 atm up to 5.0 atm. Using a thermodynamic model, a quadratic equation is found to determine the effective area of a pneumatic spring. It is established that when the pressure gauge in the pneumatic spring changes from 2.5 atm up to 5.0 atm the effective area of the pneumatic spring varies from 0.231 m2 to 0.306 m2. The scientific novelty lies in the fact that for the first time, on the basis of static experiments, the change in the effective area of the pneumatic spring of high-speed rolling stock depending on the value of the gauge pressure in the spring was established. This will make it possible to determine the forces acting on the pneumatic spring in different operating conditions, ensuring the required level of safety of rolling stock
Assessing environmental influences on radon levels: analysis of independent variables
Get PDFRegression analysis is essential for prediction analysis and variable identification since air pollution studies are complicated by competing suggestions and require careful interpretation. In the existing predictive analysis, estimating indoor radon levels is challenging due to multicollinearity issues and the existing algorithm's assumption of independent predictor variables, making it difficult to accurately assess individual effects. Hence a novel Unsupervised Bayesian Multiple Regression Analysis is used to correctly offer the specific impacts of each predictor variable by taking the complex interactions between factors in the estimation of indoor radon levels. Furthermore, in the variable identification, indoor radon levels are influenced by complex residual distributions, with existing algorithms failing to predict non-Gaussian residuals due to outlier-sensitive least squares estimation. So a novel Quadratic Discriminant Extreme Learning Machine is implemented to overcome this issue, which creates models that are better able to reliably detect the factors driving indoor radon levels and are more robust to non-Gaussian residual distributions. The proposed method demonstrates excellence in predictive analysis and variable identification achieving high coefficient of relation and low MAE
Research on the algorithm for optimal selection of detection modes for rail crack detection
Get PDFIn the application of ultrasonic guided wave testing for rail crack detection, it is necessary to select a guided wave mode that is more sensitive to cracks as the detection mode. However, ultrasonic guided waves have multi-mode and dispersive characteristics. In order to extract mode information from complex signals, this paper proposes an optimal detection mode selection method based on the sensitivity of guided wave modes to cracks. This method is different from the traditional method of determining mode types by calculating the mode velocity through the arrival time of wave packets in the time domain signal. Based on the dispersion characteristics and mode features of guided wave modes, this paper establishes a crack sensitivity evaluation index. In a wide frequency band and among numerous modes, the guided wave modes suitable for detecting cracks in different regions of the full cross-section of rails are accurately selected. Experimental results show that the guided wave modes selected by the mode selection method proposed in this paper, based on the crack area energy and crack reflection intensity evaluation indexes, can accurately identify rail cracks, laying a foundation for the research on rail crack detection and localization methods