Field drawing test of fully bonded BFRP anchor under cyclic loading

Due to the improvement of engineering material performance requirements, traditional steel anchor rods have limitations, while BFRP anchor rods have highlighted their advantages. This article focuses on the application of fully bonded BFRP anchor rods in geotechnical anchoring engineering and the construction of BFRP anchor rods. Based on the relevant roadbed slope protection anchoring projects of China Railway Eighth Bureau Group, and referring to previous experimental ideas, five sets of BFRP anchor rods with different lengths were tested for their pull-out resistance. The experimental results show that: (1) The sliding displacement of the anchor rod increases with the cyclic load, and the maximum sliding is not synchronized with the maximum load and has hysteresis and rebound. After unloading, the anchor rods with lengths of 4.8, 4.3, and 3.8 meters still have adhesive force; (2) The monitoring curve of the dynamometer is generally consistent with the design curve; (3) The key to the success of the experiment lies in the preparation of auxiliary fixtures at the loading end, the installation of strain gauges, and the waterproof treatment of wiring. This research provides a theoretical basis and reference for the optimization design and construction of BFRP anchor rods in geotechnical anchoring engineering

Research of thermal endurance of cables of secondary systems of TsGPP substation under short-circuit conditions

The article presents the results of research on thermal endurance of control cables of secondary systems of substation 500 kV “TsGPP” substation under single-phase short circuits (SC). The study is based on the combination of field experiments and numerical modeling of the computational model of the grounding, which determines the distribution of potentials on the grounding and currents on the cable shields. The results showed that when a short-circuit occurs on the OS (Outdoor Switchgear)-220 kV and OS-110 kV current density flowing through the screen may exceed the permissible values, which leads to thermal damage to cables and, as a result, an increased risk of damage to the secondary relay protection and control systems. Based on the analysis of the obtained data, recommendations for optimizing the configuration of the grounding have been proposed. Densification of local grounding and an increase in the number of connections between the shield grounding and the grounding grid leads to a reduction in the potential distribution gradient in the grounding circuit of the “TsGPP” substation. Given the soil resistivity parameters specific to the substation under study, the current levels flowing through the control cable screens have been reduced to values below the established permissible thresholds. For the first time, the results of research conducted at an actual high-voltage substation have demonstrated the feasibility of ensuring the thermal stability of control cables through the reconstruction of the grounding

Optimal control of lane changing problem of intelligent vehicle

Lanes changing is one of the basic behaviors of vehicle driving, which has a significant impact on road traffic safety and stability. Aiming at the problem of slow convergence rate in solving the optimal control problem of vehicle lane changing, an optimal lane changing control method based on hp adaptive pseudospectral method is proposed. By establishing a vehicle kinematic model, boundary constraints, and path constraints, combining with the physical process of vehicle lane changing the proposed method discretizes the control and state variables to transform the multi constraint optimal control problem into a nonlinear programming problem and the minimum vehicle lane changing time is set as the performance objective function. And also, the proposed method is compared with traditional solving methods. The simulation results show that the proposed method can effectively solve the optimal feasible lane changing trajectory and complete the lane changing maneuver process in the shortest possible time

Dynamics analysis and experiment of banana-shaped vibrating-dewatering screen

Banana-shaped Vibrating-Dewatering Screen (BVDS) is effective for dehydrate and demud sand aggregate, fine coal slime, ore and other materials. In this paper, the mechanical structure of the BVDS was revealed by means of theoretical modeling, simulation research and experimental test, and its dynamic and vibration characteristics were studied. The mathematical model was established, and the dynamic curve and spatial trajectory of the BVDS were obtained by MATLAB/Simulink software. Lissajous displacement diagram shows that the spatial motion trajectory of the shaker is an oblique line. The vibration test was carried out by using dynamic characteristic test system, and the dynamic characteristics of displacement, velocity and acceleration of the BVDS were revealed. Finally, through theoretical analysis, the changing trend of vibration characteristics of the BVDS with the increase of rotating velocity was obtained. The results show that the experimental data is basically consistent with the theoretical data, and the deviation is less than 6.58 %, which verifies the accuracy of the theoretical model. This paper provides a reference for the design and efficient operation of the BVDS

Application of statistical modelling method for determination of optimal solutions of road transport problems

The article is devoted to the use of statistical modelling to solve problems related to the functioning of road transport and mass service systems, such as car service stations. The method consists in reproducing the process under study using a probabilistic mathematical model and subsequent statistical processing of data to obtain numerical characteristics of the process. The purpose of the study is to apply the method of statistical modelling to determine optimal solutions to problems such as calculating the probability of system states, the average number of occupied channels, queuing time and other characteristics of the service station. A station with two service channels and two waiting places is considered as an object of research. The methods of probability theory, including the law of large numbers and Bernoulli's theorem, have been used to solve the set tasks. The modelling results show that in the process of station operation the probability of failure and other characteristics, such as average waiting time, can be accurately calculated using a statistical approach. The main research method is random variable modelling using uniformly distributed random numbers and their logarithmic transformations to simulate application arrival times and service times. The conclusions of the study confirm the high efficiency of the method of statistical modelling for the analysis and optimization of transport systems and mass service systems, as well as its possible application for other tasks, such as determining the capacity of transport interchanges, reliability of technical systems and other logistic processes

Estimation of the permissible level of motor transport traffic’ intensity in the urban streets as regards the pollutants’ emissions

Calculations of emissions and dispersion of pollutants in the air of streets were carried out and concentrations of pollutants in the air of streets created from emissions of motor transport were determined. Based on the calculations it was proposed that for the city of Almaty the permissible level of the motor transport traffic’ intensity is about 300,0-350,0 vehicles/hour. Under such traffic intensity content of pollutants in the atmospheric air will not exceed the sanitary standards

Analysis and study on the ballistic design of small-caliber grenade anti-UAV

With the rapid development of UAV technology, the use of unmanned weapons on the modern battlefield has innovated the combat mode and changed the form of warfare. In order to ensure national security and deal with potential war risks, it is imperative to carry out research on anti-drone weapons and equipment. Compared with the electromagnetic signal jamming and interception network anti-UAV technology, based on the existing small-caliber grenade launch platform, the technology of using projectile explosion fragments and shock waves to destroy the enemy's UAV equipment has the advantages of lower cost, faster research and development, more complete damage and higher fault tolerance. Based on fluid mechanics, projectile design theory, internal and external ballistics theory and numerical simulation technology of modern weapon systems, this paper reasonably optimizes the shape of small-caliber grenades, and uses the characteristics of prefabricated fragmentation explosion to damage different parts of the UAV, so as to achieve the effect of anti-UAV

Study on the influence of sewage pipeline construction on the foundation of the neighboring bridge

With rapid urbanization, conflicts between underground pipeline construction and existing bridge infrastructure have become increasingly prominent. This research aims to fill the gap in understanding the differential impact mechanisms and dynamic coupling effects between construction activities and bridge foundation stability. The study employs the finite element model to simulate the construction process, including working well excavation and pipe jacking, in a 120×80×30-meter three-dimensional model. Results show that both excavation and pipe jacking activities have minimal impact on the adjacent bridge foundations, with maximum horizontal displacements remaining within safe limits. This research provides a methodological framework for urban infrastructure risk assessment, offering technical references for balancing underground construction activities with existing structural protection

Enhanced photocatalytic CO2 reduction performance of Cu-Doped ZnO: synthesis, characterization, and mechanistic insights

In this study, we utilized in situ infrared spectroscopy to comprehensively analyze the behavior of copper-doped zinc oxide (Cu-ZnO) in photocatalytic CO2 reduction reactions. By pyrolyzing copper-doped ZIF-8 precursors, we achieved a uniform distribution of copper within the zinc oxide matrix. Experiments conducted under simulated sunlight conditions demonstrated that Cu-ZnO exhibits enhanced activity and selectivity in the conversion of CO2 to CO compared to undoped ZnO. The findings from in situ infrared spectroscopy indicate that copper doping significantly improves the material's ability to adsorb and activate CO2, thereby enhancing its photocatalytic performance. This study has developed the application of in situ infrared spectroscopy in surface catalysis and provided a new direction for exploring the catalytic mechanism of photocatalytic CO2 reduction

Effect of SAP internal curing on mechanical properties and durability of semi-rigid subgrade in aeolian sand

In order to improve the anti-cracking performance of the semi-rigid base and reduce the maintenance cost of the semi-rigid base, this paper adopts the orthogonal test method to study the influences of the multi-dimensional cementitious composite system, the type of SAP, the dosage of SAP and additional water intake of SAP on the mechanical properties and the dry shrinkage performance of the semi-rigid base of the aeolian sand. The test data of strength index and shrinkage index were analysed by extreme difference analysis and analysis of variance respectively, and the results showed that when the cement: fly ash is 1:4, the cementitious material: aggregate is 17:83, the aeolian sand replaces 12 % of fine aggregates, the SAP type is composite, the SAP dosage is 0.05 %, and the additional water intake of SAP is 20 times in order to get the optimal internal curingprogramme, and also provides a theoretical basis for the further application of aeolian sand in semi-rigid subgrade