Maintenance, Reliability and Condition Monitoring
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Performance improvement technology of sludge roadbed based on vibration slow release
Get PDFIn order to improve the anti-vibration properties and bearing capacity of solidified sludge, this article takes silt soil as the research object and selects sludge solidification materials with good solidification performance. The chemical element composition of muddy soil was analyzed using an energy dispersive X-ray spectrometer (EDS). The microstructure and characteristics of muddy soil and solidifying agent were characterized by transmission electron microscopy experiments (TEM). The optimal moisture content and maximum dry density of solidified sludge were analyzed using compaction tests. The unconfined compressive strength test was used to evaluate the bearing capacity and strength variation of solidified sludge. The vibration characteristics of sludge under different testing times and frequencies was studied. The research results indicate that the solidifying agent could reduce the moisture content of muddy soil significantly, improve the anti-vibration properties and bearing capacity of muddy soil effectively, which provide relevant basis for improving the performance and anti-vibration performance of solidified sludge used for roadbed filling. This study could provide innovative reference for the vibration and performance of solidified sludge used in roadbed filling
Development of gear fault identification of wind turbine’s transmission system based on VMD and FNN
Get PDFIn order to improve the safety of wind turbine, this paper takes the high-speed spur gear on output shaft in the transmission system of the wind turbine as the study object. The original signals of the gear in different fault states which obtained from the experimental platform decompose by the empirical mode decomposition method (EMD) and the variational mode decomposition method (VMD), respectively. Then the different gear fault types’ eigenvectors were built. Fuzzy neural network (FNN) is adopted to learn the fault types and eigenvector samples of gears, and then the fault types of gears are identified. It is found that the fault features decomposed by VMD method have reached a high accurate recognition rate point to the fact that VMD has good applicability in the fault recognition of gear in wind turbine
Influence of the welding cycle on the parameters of material damageability of the high-strength steel connection with an austenitic seam
Get PDFThe distribution of macrohardness of the material of a welded joint made of high-strength steel in the vicinity of a weld with an austenitic structure has been studied. The characteristics of the material's homogeneity, technological damageability, and the intensity of its growth have been determined using the LM-hardness method. The obtained characteristics of the material are considered according to the distance from the axis of the weld. It is shown that using the dispersion of important physical and mechanical characteristics to analyze the material homogeneity makes it possible to consider the differences in relation to the base material, structure, and properties of the weld. The method used in the work to assess the material damageability can be used for a welded joint that is heterogeneous in material. The obtained results are applicable in developing the technique of heterogeneous weld joints made of high-strength steels, as well as in the study of existing welded critical structures of long-term operation, in particular, main pipelines
Tensor analysis of tornadoes: a new analytical and numerical model
Get PDFThis research proposes a new mathematical formulation of tornadoes based on the theory of tensor analysis and simulation in a non-inertial dynamics framework, both in two and three dimensions. This model may show the spherical upward movement of air in a tornado without taking into account vertical convection. A tornado requires several elements, including geocentric latitude, the Coriolis effect, increased airspeed in the upper atmosphere, and increased air pressure. Computing the three-dimensional location of the tornado or hurricane, as well as the mathematical models of airflow motion and the Earth's rotation in three-dimensional (3D) space, can determine a tornado's airflow characteristics. To show tornado patterns, we employed computer software that computed motion dynamics and did numerical computations. The results of 2-D modeling and simulation indicated that the greater the initial tornado angular speed, the larger the tornado area. Three-dimensional modeling and simulation also show that tornadoes are more powerful at higher geocentric latitude angles. The novelty of this study is that this model can be used to explain tornado patterns. In our research, we combine tensor analysis, computational modeling, as well as 2D and 3D simulations for simulating tornadoes for the first time. The scientific application of this finding is that researchers at the Meteorology, Climatology, and Geophysics Agency will be able to analyze a tornado and geophysical phenomena more readily with simulations and models
Secure metric dimension of new classes of graphs
Get PDFThe metric representation of a vertex v of a graph G is a finite vector representing distances of v with respect to vertices of some ordered subset S⊆V (G). If no suitable subset of S provides separate representations for each vertex of V(G), then the set S is referred to as a minimal resolving set. The metric dimension of G is the cardinality of the smallest (with respect to its cardinality) minimal resolving set. A resolving set S is secure if for any v∈V–S, there exists x∈S such that (S–{x})∪{v} is a resolving set. For various classes of graphs, the value of the secure resolving number is determined and defined. The secure metric dimension of the graph classes is being studied in this work. The results show that different graph families have different metric dimensions
Mathematical simulation modeling analysis of sub-sea tunnel blasting based on grey correlation
Get PDFBlasting in the ocean tunnel has a great impact on Marine life and seabed vegetation, so it is necessary to control the impact of blasting vibration on the surrounding Marine environment. In this paper, taking Xiamen Tunnel as an example, the blasting vibration response characteristics of undersea tunnel are studied, and the velocity attenuation rules of tunnel structure in different directions are obtained. The grey correlation theory is innovatively applied to analyze the correlation degree of factors affecting the blasting vibration effect of the undersea tunnel, and the key factors and secondary factors affecting the blasting vibration effect of the tunnel are determined. The grey correlation theory is used to analyze the correlation degree between the blasting vibration effect of the cross-tunnel, which is conducive to improving the safety and stability of tunnel construction. It provides a new idea and method for vibration control of similar projects
Structural analysis and optimal design of a spherical thin-walled stainless steel water tank without reinforced tie ribs
Get PDFA spherical thin-walled stainless steel water tank without reinforced tie ribs has been designed to address the issues of easy fracture and corrosion of the ribs, difficulty in maintenance and cleaning, and short service life exposed during the use of thin-walled stainless steel water tanks with reinforced tie ribs. Firstly, an analytical model of a flat steel thin-walled water tank without reinforced tie ribs was established and subjected to static analysis under water pressure. The deformation and stress distribution patterns of the side molded plate of the flat box were obtained. Secondly, a spherical non ribbed thin-walled stainless steel water tank structure was designed with circular cross-section under different box bulge parameters, and its mechanical response characteristics under water pressure load were analyzed. A strengthening scheme was designed for the bottom box molded plate. Once again, optimize the combination design of the box scheme and the reinforcement scheme, and analyze their static, thermodynamic, and thermal solid coupling performance. Finally, the Latin Hypercube Sampling method was used to generate experimental design samples, and a response surface approximation model of a spherical thin-walled stainless steel water tank without reinforced tie ribs was constructed. The wall thickness of the box molded plate, skeleton, and reinforcement were used as design variables, and the maximum deformation and maximum equivalent stress were used as constraints. The lightweight design was carried out with the goal of minimizing mass. The research results indicate that the design program and parameter selection method for spherical thin-walled stainless steel water tanks without reinforced tie ribs proposed in the article are efficient and feasible, and can provide technical reference and theoretical support for the layout and overall optimization design of non ribbed thin-walled stainless steel water tank structures
A precise localization algorithm for unmanned aerial vehicles integrating visual-internal odometry and cartographer
Get PDFAccurate positioning in space is an important foundation for ensuring the stability of autonomous flight and successful mapping and navigation of unmanned aerial vehicles (UAVs). At present, the SLAM algorithm based on the Cartographer algorithm for real-time positioning and mapping is widely used in fields such as robot navigation and autonomous driving. However, in the context of UAV applications, this algorithm has a high dependence on the amount of point cloud information in the surrounding environment, and cannot achieve precise positioning in open spaces with insufficient lighting and fewer feature points, resulting in significant mapping errors. In order to solve the problem of low positioning estimation accuracy in the Cartographer algorithm in above environment, this paper proposes a precise positioning algorithm for UAVs that integrates VIO and Cartographer. This algorithm can continuously output more accurate position estimation information during UAV flight, compensating for the problem of inaccurate position estimation caused by partial feature loss or coordinate system drift in point clouds. In addition, this algorithm ensures navigation obstacle avoidance in narrow spaces by improving positioning accuracy and mapping accuracy, making it more applicable in the field of UAVs. Finally, the effectiveness of the proposed positioning algorithm was verified through experimental analysis of the Cartographer dataset and practical testing of UAVs in real scenarios
Advances of 3D printing in oral oncology: personalized technologies for patients – a narrative review
Get PDFThis study presents a narrative review of the literature that focuses on the substantial relevance and practical application of additive manufacturing and 3D printing in the context of oncology patients in the dental field. To address innovative technologies for diagnosis and treatment, this review underscores the progressive role of 3D printing in the creation of customized models for rehabilitation, surgical planning, prosthetics, examinations, and even tissue engineering. We analyzed five articles focused on the following categories: applications, benefits, and challenges associated with additive manufacturing; 3D printing; head and neck cancer; as well as assistive technology in the context of improving the effectiveness of treatments for people with this type of neoplasm. Oropharyngeal squamous cell carcinoma stood out as the most cited neoplasm for the use of 3D printing. 3D printing has played a significant role in transforming oral cancer treatment by providing customized solutions and enhancing outcomes: custom implants and prosthetics, patient-specific radiotherapy accessories, dose modulation devices, and improved preoperative planning. Additionally, 3D printing enables the production of complex medical devices in a single process, reducing steps and potentially costs. This also opens doors to creating more affordable solutions and extends the reach of personalized treatment to a greater number of patients. Continuous advancements in research and development of additive manufacturing and 3D printing technologies demonstrate significant potential for optimizing treatments and improving outcomes for patients with head and neck cancer
Interconnections between local Schumann resonances and episodes of kidney disease
Get PDFThe aim of the study was to evaluate the interconnections between local Schumann resonances of the Earth’s magnetic field and episodes of kidney disease. Materials and Methods: Study participants included 716 males and 624 females who had episodes of kidney disease during the period of 1 January 2021 to 31 December 2021 and attended the Department of Nephrology at the Hospital of Lithuanian University of Health Sciences, Kauno klinikos. Time varying magnetic field data was collected at the magnetometer site located in Lithuania. Results and Conclusions: The study results support the hypothesis that the Earth’s magnetic field has a relationship between the number of nephrology patient hospitalizations per week and the average weekly local Schumann resonances strength in different frequency ranges. Working hypotheses are proposed for the mechanisms of the influence of the Earth’s electromagnetic field on kidney function: а) quantum mechanical features of the atomic composition of renal tissue molecules determine a kidney-specific reaction; b) cyclotron resonance mechanism; c) resonant response of cells of morphological structures of kidney tissue to external bioactive frequencies in the range of 6-8 Hz; d) mechanism of indirect influence of blood as a magnetically saturated medium