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In urban signalized intersections, because of the mixing of straight-going and right-turn vehicles in the straight-right shared lane, the straight traffic may block the rear right-turn vehicles from crossing the intersection during the red light, resulting in additional waiting time for right-turn vehicles. To address this problem, this study proposed the dynamic straight-right lane (DSRL) design and corresponding signal control schedule, which separates the straight-going and right-turn vehicles in space–time, making vehicles enter the intersection in an orderly manner. Then, the key parameters of the signal timing scheme were identified, and the physical significance of the key parameters of the optimal signal timing and the calculation models were given by discussing the optimal process of traffic flow operation at the signalized intersection. Finally, taking a realistic T-shaped signal intersection inlet lane as an example, the simulation verification platform was built by VISSIM to analyze the effects of variables on the performance of the DSRL proposed in this study. The results showed that the design proposed in this study can significantly reduce the right-turn vehicle delay without changing the overall layout of the signal intersection, and the total delay optimization rate at the intersection can always reach 10%–30%. [ABSTRACT FROM AUTHOR]

Abstract Among the many adverse geological disasters, the surge water disaster in karst areas causes the greatest loss to underground engineering construction, so it is necessary to carry out relevant research on the management of surge water disaster in karst pipelines. This study presents the creation of an oily epoxy resin magnetic convergence grouting material (OEMS) specifically developed to prevent water infiltration in pipelines. A self-designed visual karst pipeline grouting simulation system was used to conduct an experimental study on the diffusion and plugging behavior of magnetic slurry grouting. A model was constructed to simulate the migration of a magnetic slurry in water inrush circumstances. The model is based on the theory of slurry diffusion and the concept of magnetic adsorption. The results suggest that:(i) The best performance in grouting sealing is achieved when the ratio of new OEMS epoxy resin A liquid to B liquid is 2:1, and the blending ratio of flyash and Fe3O4 powder falls between 25 and 55%. (ii) The primary and secondary correlations among the parameters that affect the rate of change in flow rate, plugging pressure, and slurry retention rate are as follows: Hydrodynamic velocity has the greatest correlation, followed by plugging length, Fe3O4 power ratio, and flyash mixture ratio. (iii) The validity of the model is verified by comparing empirical observations with calculated theoretical values.

Aiming at the current peanut pickup combine harvester seedling vines crushing mechanism operation qualified seedling length rate is low, the impurity rate is high, and the seedling vines crushing mechanism is optimized design. On the basis of the material characteristics of peanut seedling vines, taking the crushing mechanism as the research carrier, the interaction mechanism of the seedling vine mechanism was analyzed. Establish the mechanical model and motion trajectory model in the crushing process, simulate the peanut seedling vines crushing process based on the discrete element method, analyze the influence of the cutter shaft rotational speed, movement speed, and bending angle on the crushing of peanut seedling vines, and establish the regression model, and the results of the research show that the influence factors in the main order of priority are: knife shaft speed > movement speed > bending angle The optimal parameter combination is knife shaft speed 2171.94 r/min, movement speed 0.79 m/s, and bending angle 45°. According to the field test conditions, it is determined that the knife shaft rotational speed of 2170 r/min, movement speed of 0.8 m/s, and bending angle of 45° can make the peanut seedling vines crushing mechanism of the work performance to achieve a qualified seedling length rate of 97.292%, the rate of impurity content of 2.746%, and the error with the predicted value is less than 2%, which indicates that this study can provide a reference for the optimal design of the seedling vines crushing mechanism of the peanut pickup combine harvester. [ABSTRACT FROM AUTHOR]

This study analyzes the key processes of hydrometallurgical technology, constructs an optimization con- trol model, and improves the particle swarm algorithm using adaptive inertia weight and simulated annealing operators to achieve optimization control of hydrometallurgical technology. Simulation test results show that in the test on the A wind farm optimization dataset, the AIWSAO - PSO algorithm stabilizes after 225 iterations with a fitness value of 0. 165. At 100 iterations, the algorithm's root mean square error, mean absolute error, and relative standard deviation (RSD) are 0.008 0, 0.004 5, and 0.971%, respectively. In the optimization control model for hydrometallurgical technology, the obtained comprehensive benefit value is 1.9 x 105 yuan/h, with an absolute error of about 0. 1 x 104 yuan/h from the target expected value. This achieves the optimization control of the hydrometallurgical process and provides technical support for similar optimization control applications. [ABSTRACT FROM AUTHOR]

In order to test the influence of the structural design of a no-tillage corn precision planter on vibration stability performance, a vibration model was constructed with the help of MATLAB/Simulink, and it was concluded that the vibration response curve of the no-tillage corn precision planter was relatively smooth. Based on the theory of the discrete element method (DEM), taking the planting apparatus of the no-tillage corn precision planter as the research object, firstly, a DEM single-factor test was carried out to investigate the effects of the slot inclination angle, number of slots, and rotational speed of the planter plate on the disturbance performance. Then, a three-factor, three-level orthogonal test was conducted with the maximum amount of seed discharging, the minimum average speed, and the minimum average kinetic energy as the final optimization objectives, and the qualified rate of seed discharging and the leakage rate as the evaluation indexes. The results show that the larger the inclination angle, the higher the number of slots, and the faster the rotational speed, the more violent the particle disturbance. At the same time, when the slot inclination angle of the planter plate is 60°, the number of slots is 20, and the rotational speed is 55 rpm, the seed discharge efficiency is the highest, at this time, the seed discharge qualification rate of maize particles is 95%, and the leakage rate is 3%; the results of this test can provide technical support for the research of the same kind of precision sowing equipment in the future. [ABSTRACT FROM AUTHOR]

As a new type of mine geological disaster, water-sand inrush has the characteristics of concealment, sudden onset, difficulty in monitoring, and strong destruction. Therefore, exploring the characteristics of overlying rock mining degradation and the disaster mechanism of water-sand inrush has guiding significance for the prevention and control of loose layer water hazard. Firstly, the influence mechanism of different material proportioning on the strength and permeability characteristics of similar materials is studied through similar material proportioning and testing experiments, and a new solid-fluid coupling similar material suitable for simulating soft rock layers is developed. Then, by using the test system for water-sand inrush, similar simulation tests are conducted for mining under the condition of a single water-bearing structure capping thin and medium thick bedrock, and a double layered structure capping thin bedrock. The characteristics of mining crack and the disaster mechanism of water-sand inrush under the above strata structure conditions are analyzed. The test results show that the new solid-fluid coupling similar material has the characteristics of water resistance, anti disintegration, anti softening, low permeability, low strength, and low plasticity, and the permeability coefficient decreases exponentially with the increase of calcium carbonate content, while the uniaxial compressive strength exhibits a quadratic polynomial growth characteristic. The first weighting stage and the first periodic weighting stage of mining shallow and thin bedrock are easy to induce water-sand inrush. The mining cracks present an “OX” distribution on the plane, and as the thickness of bedrock and the clay layer at the bottom of the loose layer increases, the bedrock gradually transforms from tensile shear failure to tensile failure, and the morphology of the cracks also changes. At the same time, the opening and smoothness of cracks are reduced, which can reduce the inducing risk and harm degree of water-sand inrush. The ratio of crack opening to sand particle size , as well as the smoothness of crack, are the key factors determining the occurrence and severity of water-sand inrush.

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aiming at the high crushing rate and impurity rate of corn kernel machine harvesting in the Huanghuaihai region, a longitudinal flow conical variable pitch threshing device is designed, which adopts the combined threshing element of "plate teeth + ribs" and the combined threshing concave plate of "leftward round tube type + vertical round tube type". The cob model was established, and the force analysis of the cob threshing process was carried out, and the type of threshing drum and the installation angle of the threshing concave plate round tube were determined as the main influencing factors, and the collision force on the corn cob was taken as the test index. Using EDEM discrete element simulation software, simulation tests were carried out on different types of threshing drums and threshing concave plates with different installation angles of round tubes with corn cobs, and the better threshing method was finally determined: a conical threshing drum at a drum speed of 450 r/min, and a combination of left-facing round-tube-type + vertical round-tube-type threshing concave plates with an installation angle of 10° (front-sparse and back-dense type) were used. Compared with the vertical circular tube type threshing concave plate, the corn cob contact force decreased from 313.5 N to 247.3 N, which was optimal for threshing in the range allowed by the corn kernel destructive force. [ABSTRACT FROM AUTHOR]

Copyright of Coal Geology & Exploration is the property of Xian Research Institute of China Coal Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Karst sinkholes with natural negative landform provide favorable conditions for the pumped storage reservoir construction for less excavation work. However, the construction of the reservoir would plug the natural karst channels for water and air, which would cause remarkable air pressure in karst channels when the groundwater level fluctuates. A large laboratory simulation test was carried out to study the air pressure variation of a reservoir built on the karst sinkhole. The air pressure in the karst channel and inside the model was monitored during the groundwater rising and falling process. Result showed that the variation of air pressure in the karst channel and the surrounding rock exhibited a high degree of similarity. The air pressure increased rapidly at the initial stage of water level rising, followed by a slight decrease, then the air pressure increased sharply when the water level approached the top of the karst cave. The initial peak of air pressure and the final peak of air pressure were defined, and both air pressure peaks were linearly increasing with the water level rising rate. The negative air pressure was also analyzed during the drainage process, which was linearly correlated with the water level falling rate. The causes of air pressure variation in karst channels of a pumped storage reservoir built on the karst sinkhole were discussed. The initial rapid increase, then slight decrease and final sudden increase of air pressure were controlled by the combined effects of air compression in karst channel and air seepage into the surrounding rock. For the drainage process, the instant negative air pressure and gradual recovering of air pressure were controlled by the combined effects of negative air pressure induced by water level falling and air supply from surrounding rock. This work could provide valuable reference for the reservoir construction in karst area. [ABSTRACT FROM AUTHOR]

Aiming at the problem of water burst plugging in karst pipelines, in this paper, a new type of waterborne epoxy resin magnetic self-polymerization grouting material (WEMS) suitable for karst pipeline water burst plugging was developed, and a visual simulation test device for karst pipeline water burst grouting plugging was designed and built. Through the orthogonal test of grouting plugging, the influence of different factors on the effect of grouting plugging was analyzed, and the shear mechanism of magnetic slurry magnetization plugging was also analyzed. The results showed that (i) the best grouting sealing performance was achieved when the new WEMS had a water–cement ratio of 0.35–0.55 and Fe3O4 powder misery of 20–40%. (ii) The primary relationship between the factors affecting the dynamic water flow rate and slurry retention is Fe3O4 power ratio > plugging length > water–cement ratio. (iii) The relationship equation was established between the shear strength of magnetic self-polymerizing slurry and the magnetic field strength, blocking length, and slurry ratio. [ABSTRACT FROM AUTHOR]

To investigate the impact of different cutter structures on the crushing effect of forage stalks at various rotational speeds, this study designed five types of crushing cutters. The effects of cutter structure and rotational speed on the crushing effect of the forage crusher were examined using the discrete element method, a single-factor test. An orthogonal test was conducted, with the percentage of bond breakage as the evaluation index, and tool type and tool speed as influencing factors. The results of the orthogonal test were analyzed using range analysis. The findings revealed that the quality of alfalfa stalk crushing varied depending on the crushing structure and rotational speed. Within a certain rotational speed range, the crushing effect improved as the rotational speed increased. However, beyond a certain value, the improvement in the crushing effect became slower. Notably, the hob-type crushing structure exhibited the best crushing effect at 2400 r/min. [ABSTRACT FROM AUTHOR]

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Regarding the system composition of the heavy haul railway train control system based on Beidou, the key equipment of the system is taken as the tested equipment. A semi-physical simulation testing system architecture is designed, and key technologies and solutions such as the simulation of the Beidou Navigation Satellite System, block system simulation, and heavy haul train simulation are analyzed. Through system implementation, it has been verified that the design scheme of this simulation testing system is feasible, capable of executing typical operating scenarios of the heavy haul railway train control system based on Beidou, supporting feasibility verification of system technical solutions, facilitating equipment debugging and testing, providing environmental support for equipment research & development and engineering implementation, and offering strong technical support for laboratory system integration testing. [ABSTRACT FROM AUTHOR]

Existing testing methods for Automatic Emergency Braking (AEB) systems mostly rely on standard-based qualitative analysis of specific scenarios, with a focus on whether collisions occur. To explore scenarios beyond the standard conduct, a comprehensive testing model construction and analysis, and provide a more quantitative evaluation of AEB performance, this study extracted three typical hazardous driving scenarios from the KITTI (The Automated Driving dataset was created by the Karlsruhe Institute of Technology in Germany and the Toyota Institute of Technology in the United States) naturalistic driving dataset using kinematic data. A DME (Data Missing Estimation) scene construction method was proposed, and these scenarios were simulated and reconstructed in PRESCAN (PRESCAN is an automotive simulation software owned by Siemens, Munich, Germany). A C-AEB (Curve-Automatic Emergency Braking) testing model was developed and tested based on simulations. Finally, a BCEM (Boundary collision evaluation model) was proposed to quantitatively evaluate AEB performance. The focus of the analysis was on the identified cornering scenario A (severely failed AEB scenario). A C-AEB testing model was constructed based on the DME scene construction method for this cornering AEB failure scenario, and it was evaluated using the BCEM. The study found that the average performance degradation rate (performance degradation rate refers to the ratio of AEB performance in the current scenario compared to the standard straightaway test) of the AEB system in this cornering scenario reached 75.44%, with a maximum performance degradation rate of 89.47%. It was also discovered that the severe failure of AEB in this cornering scenario was mainly caused by sensor system perception defects and limitations of traditional AEB algorithms. This fully demonstrates the effectiveness of our testing and evaluation methodology. [ABSTRACT FROM AUTHOR]

The automated storage and retrieval system (AS/RS) has been developed rapidly and has been widely used in various fields. To achieve the ultimate goal of improving the efficiency of warehouse operation, this article studies the problem of goods locationallocation on the premise of a comprehensive analysis of the efficiency of automated warehouses and the overall stability of shelves. The mathematical model is established. Traditional Tabu search algorithms depend on Tabu table construction to avoid multiple continuous cycles that may occur in the direct search process. In this article, the improved algorithm can directly search and store in the Tabu table to prevent the algorithm from infinite search. A complete solution in that Tabu list continues to be passed to act as a point solution to replace the iteratively update product until a set iteration interval of the product is completed. The machine learning system can get the optimal solution. The improved algorithm is applied to solve the model, and the running results and the performance of the algorithm itself are obtained. The improved Tabu Search algorithm has more advantages in the process of solving the model because it reduces the size of the whole problem. The algorithm also uses the penalty optimization function as a measure of each solution. The greater the penalty is, the worse the solution is, and the smaller the penalty is, the better the solution is. The operation process of the material in and out of the warehouse in one day is studied, and the validity of the optimization scheme of goods location allocation is verified by substituting specific data for the solution. Finally, the case of goods in and out of the warehouse is simulated by using simulation software, and the running state and efficiency of the stacker are displayed according to the data. The Tabu direct search table is combined with the structure and function of the principle of amnesty direct search to achieve the goal of direct search and decisionmaking. The equilibrium coefficient of its operation is calculated by using the data, which proves that the scheme is feasible and has practical significance and research value. [ABSTRACT FROM AUTHOR]

Copyright of Automotive Digest is the property of Automotive Digest Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Due to its special working conditions, offshore wind turbine will bear large direct and indirect loads under the combined action of air flow and wave flow. In this paper, a variable pitch system composed of variablepitch motorand variable pitch bearing is improved, and the characteristics of system's bending moment, torque, vibration and other physical quantities under the action of multiple physical loads are verified, and the mechanical response characteristics of floating wind turbine under the control of unified variable pitch and independent variable pitch are studied under the running conditions at sea. The results show that mechanical structure of uniform pitch is compared with that of independent pitch, the independent variable pitch structure can effectively reduce the mean oscillation value of wind turbine tower in the parallel direction of air flow by optimizing control strategy, and reduce the thrust at the hub of wind turbine and the bending moment at the root of tower, but increase the vibration frequency and fatigue load of offshore wind turbine tower along parallel direction of air flow. Reduce the fatigue life of equipment. The research results can be used as a reference to reduce the variable pitch control and vibration suppression of offshore wind turbines and improve the reliability of wind turbines.

[Objective]The usual agricultural machinery navigation focuses on the tracking accuracy of the tractor, while the tracking effect of the trailed implement in the trailed agricultural vehicle is the core of the work quality. The connection mode of the tractor and the implement is non-rigid, and the implement can rotate around the hinge joint. In path tracking, this non-rigid structure, leads to the phenomenon of non-overlapping trajectories of the tractor and the implement, reduce the path tracking accuracy. In addition, problems such as large hysteresis and poor anti-interference ability are also very obvious. In order to solve the above problems, a tractor-implement path tracking control method based on variable structure sliding mode control was proposed, taking the tractor front wheel angle as the control variable and the trailed implement as the control target.[Methods]Firstly, the linear deviation model was established. Based on the structural relationship between the tractor and the trailed agricultural implements, the overall kinematics model of the vehicle was established by considering the four degrees of freedom of the vehicle: transverse, longitudinal, heading and articulation angle, ignoring the lateral force of the vehicle and the slip in the forward process. The geometric relationship between the vehicle and the reference path was integrated to establish the linear deviation model of vehicle-road based on the vehicle kinematic model and an approximate linearization method. Then, the control algorithm was designed. The switching function was designed considering three evaluation indexes: lateral deviation, course deviation and hinged angle deviation. The exponential reaching law was used as the reaching mode, the saturation function was used instead of the sign function to reduce the control variable jitter, and the convergence of the control law was verified by combining the Lyapunov function. The system was three-dimensional, in order to improve the dynamic response and steady-state characteristics of the system, the two conjugate dominant poles of the system were assigned within the required range, and the third point was kept away from the two dominant poles to reduce the interference on the system performance. The coefficient matrix of the switching function was solved based on the Ackermann formula, then the calculation formula of the tractor front wheel angle was obtained, and the whole control algorithm was designed. Finally, the path tracking control simulation experiment was carried out. The sliding mode controller was built in the MATLAB/Simulink environment, the controller was composed of the deviation calculation module and the control output calculation module. The tractor-implement model in Carsim software was selected with the front car as a tractor and the rear car as the single-axle implement, and tracking control simulation tests of different reference paths were conducted in the MATLAB/Carsim co-simulation environment.[Results and Discussions]Based on the co-simulation environment, the tracking simulation experiments of three reference paths were carried out. When tracking the double lane change path, the lateral deviation and heading deviation of the agricultural implement converged to 0 m and 0° after 8 s. When the reference heading changed, the lateral deviation and heading deviation were less than 0.1 m and less than 7°. When tracking the circular reference path, the lateral deviation of agricultural machinery tended to be stable after 7 s and was always less than 0.03 m, and the heading deviation of agricultural machinery tended to be stable after 7 s and remained at 0°. The simulation results of the double lane change path and the circular path showed that the controller could maintain good performance when tracking the constant curvature reference path. When tracking the reference path of the S-shaped curve, the tracking performance of the agricultural machinery on the section with constant curvature was the same as the previous two road conditions, and the maximum lateral deviation of the agricultural machinery at the curvature change was less than 0.05 m, the controller still maintained good tracking performance when tracking the variable curvature path.[Conclusions]The sliding mode variable structure controller designed in this study can effectively track the linear and circular reference paths, and still maintain a good tracking effect when tracking the variable curvature paths. Agricultural machinery can be on-line in a short time, which meets the requirements of speediness. In the tracking simulation test, the angle of the tractor front wheel and the articulated angle between the tractor and agricultural implement are kept in a small range, which meets the needs of actual production and reduces the possibility of safety accidents. In summary, the agricultural implement can effectively track the reference path and meet the requirements of precision, rapidity and safety. The model and method proposed in this study provide a reference for the automatic navigation of tractive agricultural implement. In future research, special attention will be paid to the tracking control effect of the control algorithm in the actual field operation and under the condition of large speed changes.

Abstract To study the evolution rules and behaviors of heat transport in a sandstone geothermal reservoir caused by cooled water reinjection, this research focuses on the quantitative relationship among reinjection parameters and the thermal breakthrough time of production wells. The permeation, tracer, and reinjection tests were conducted in a simulation model using a large sand tank in conjunction with the numerical simulation method based on COMSOL Multiphysics. Subsequently, sensitivity analysis and nonlinear fitting were performed to investigate the effects of fluid viscosity and density on the reinjection process, and to analyze the impact of reinjection parameters on the thermal breakthrough time of production wells, along with their underlying mechanisms and law. The results indicate that the migration velocity of reinjection water is greater in coarse sand layer compared to that in medium sand layer, and the thermal breakthrough time t is linearly correlated with reinjection rate (Q) raised to the power of − 0.85, temperature difference (ΔT) raised to the power of − 0.21, and spacing between the production and reinjection wells (R) raised to the power of 1.4. The correlation equation and analysis show that when the temperature difference between production and reinjection ΔT is more than 30 ℃, the influence of ΔT on the thermal breakthrough time of production well becomes weak, because ΔT exerts an effect on the thermal breakthrough time of production well t by influencing the relative position of the 18.5 ℃ isotherm in the temperature transition region. The error in reinjecting high-temperature fluid into low-temperature fluid may be corrected by introducing a viscosity correction coefficient α μ.

ObjectivesThe aim of this paper is to obtain test scenarios of autonomous collision avoidance for inland waterway ships by modeling. MethodsStarting with the automatic identification system (AIS) and radar data collection and fusion method, a ship navigation data collection and fusion system is established. Taking the inland waterway between the Three Gorges Dam and Gezhouba Dam as an example, ship scenario elements are collected and analyzed, and a parametric generation method of inland waterway collision avoidance test scenarios is proposed which can automatically generate a ship collision avoidance test scenario by setting a series of parameters. Taking two-ship and multi-ship encounters scenario as examples, a series of test scenarios are generated and simulated. ResultsThe collision avoidance simulation tests results show that the parameterized test scenario generation method proposed herein can effectively test the autonomous ship collision avoidance algorithm. ConclusionsThe research providing a basis for improving the pertinence and practicality of inland river smart ship collision avoidance testing.

Aiming at the current peanut pickup combine harvester seedling vines crushing mechanism operation qualified seedling length rate is low, the impurity rate is high, and the seedling vines crushing mechanism is optimized design. On the basis of the material characteristics of peanut seedling vines, taking the crushing mechanism as the research carrier, the interaction mechanism of the seedling vine mechanism was analyzed. Establish the mechanical model and motion trajectory model in the crushing process, simulate the peanut seedling vines crushing process based on the discrete element method, analyze the influence of the cutter shaft rotational speed, movement speed, and bending angle on the crushing of peanut seedling vines, and establish the regression model, and the results of the research show that the influence factors in the main order of priority are: knife shaft speed > movement speed > bending angle The optimal parameter combination is knife shaft speed 2171.94 r/min, movement speed 0.79 m/s, and bending angle 45°. According to the field test conditions, it is determined that the knife shaft rotational speed of 2170 r/min, movement speed of 0.8 m/s, and bending angle of 45° can make the peanut seedling vines crushing mechanism of the work performance to achieve a qualified seedling length rate of 97.292%, the rate of impurity content of 2.746%, and the error with the predicted value is less than 2%, which indicates that this study can provide a reference for the optimal design of the seedling vines crushing mechanism of the peanut pickup combine harvester.

In order to test the influence of the structural design of a no-tillage corn precision planter on vibration stability performance, a vibration model was constructed with the help of MATLAB/Simulink, and it was concluded that the vibration response curve of the no-tillage corn precision planter was relatively smooth. Based on the theory of the discrete element method (DEM), taking the planting apparatus of the no-tillage corn precision planter as the research object, firstly, a DEM single-factor test was carried out to investigate the effects of the slot inclination angle, number of slots, and rotational speed of the planter plate on the disturbance performance. Then, a three-factor, three-level orthogonal test was conducted with the maximum amount of seed discharging, the minimum average speed, and the minimum average kinetic energy as the final optimization objectives, and the qualified rate of seed discharging and the leakage rate as the evaluation indexes. The results show that the larger the inclination angle, the higher the number of slots, and the faster the rotational speed, the more violent the particle disturbance. At the same time, when the slot inclination angle of the planter plate is 60°, the number of slots is 20, and the rotational speed is 55 rpm, the seed discharge efficiency is the highest, at this time, the seed discharge qualification rate of maize particles is 95%, and the leakage rate is 3%; the results of this test can provide technical support for the research of the same kind of precision sowing equipment in the future.

The concept of digital education has produced an unnoticeable impact on the teaching of Civics courses in colleges and universities. The study starts from the digital transformation of the curriculum ideological and political education in college courses to analyze and explore, based on the Internet of Things (IoT) technology to collect data from students’ campus card data, combined with the improved K-means clustering algorithm and correlation matrix, to establish a digital assessment model of curriculum ideological and political education based on the correlation matrix. The model’s data mining performance is evaluated through simulation tests. Then, students of a higher vocational college are selected as the research object, and the model is used to realize the construction of student portraits and the cluster analysis of student behavior and to mine the association rules between student behavior and the effect of curriculum ideological and political education. The data fluctuation range of this paper’s method is small and stable, within 0.35~0.50, with better data analysis performance. The model categorizes the sample students into 6 types of consumption regularity behaviors, 8 types of life regularity behaviors and 5 types of study effort level behaviors, and obtains 9 association rules between students’ behaviors and the effectiveness of Civic and Political teaching. The digital evaluation of curriculum ideological and political education can be effectively achieved using the campus card data mining model based on matrix association, as evidenced by the empirical analysis.

To study the evolution rules and behaviors of heat transport in a sandstone geothermal reservoir caused by cooled water reinjection, this research focuses on the quantitative relationship among reinjection parameters and the thermal breakthrough time of production wells. The permeation, tracer, and reinjection tests were conducted in a simulation model using a large sand tank in conjunction with the numerical simulation method based on COMSOL Multiphysics. Subsequently, sensitivity analysis and nonlinear fitting were performed to investigate the effects of fluid viscosity and density on the reinjection process, and to analyze the impact of reinjection parameters on the thermal breakthrough time of production wells, along with their underlying mechanisms and law. The results indicate that the migration velocity of reinjection water is greater in coarse sand layer compared to that in medium sand layer, and the thermal breakthrough time t is linearly correlated with reinjection rate (Q) raised to the power of − 0.85, temperature difference (ΔT) raised to the power of − 0.21, and spacing between the production and reinjection wells (R) raised to the power of 1.4. The correlation equation and analysis show that when the temperature difference between production and reinjection ΔT is more than 30 ℃, the influence of ΔT on the thermal breakthrough time of production well becomes weak, because ΔT exerts an effect on the thermal breakthrough time of production well t by influencing the relative position of the 18.5 ℃ isotherm in the temperature transition region. The error in reinjecting high-temperature fluid into low-temperature fluid may be corrected by introducing a viscosity correction coefficient αμ. [ABSTRACT FROM AUTHOR]

Medical and health field is a hot application field of wireless sensor networks. How to correctly refine and classify telemedicine sensor data is the research focus in related fields. Therefore, a detailed classification mathematical model simulation of telemedicine sensor data based on multi feature fusion is proposed. On the basis of telemedicine sensor data acquisition, it is preprocessed to reduce the computational overhead of detailed classification. The reliability features of the preprocessed telemedicine sensing data are extracted, the extracted features are fused by the principal component analysis method, and the refined classification model of telemedicine sensing data is constructed based on the principle of machine learning. The fused features are input into the model to complete the refined classification of telemedicine sensing data. The experimental results show that the correct refinement classification rate of the proposed method is more than 90%, the refinement classification accuracy is higher than 98.5%, the convergence speed is good, and the refinement classification time is 4 ~ 12 s, which proves that the correct refinement classification rate and accuracy of the proposed method are high, the classification time is short, and has good application performance. [ABSTRACT FROM AUTHOR]

[Objective] The usual agricultural machinery navigation focuses on the tracking accuracy of the tractor, while the tracking effect of the trailed implement in the trailed agricultural vehicle is the core of the work quality. The connection mode of the tractor and the implement is non-rigid, and the implement can rotate around the hinge joint. In path tracking, this non-rigid structure, leads to the phenomenon of non-overlapping trajectories of the tractor and the implement, reduce the path tracking accuracy. In addition, problems such as large hysteresis and poor anti-interference ability are also very obvious. In order to solve the above problems, a tractor-implement path tracking control method based on variable structure sliding mode control was proposed, taking the tractor front wheel angle as the control variable and the trailed implement as the control target. [Methods] Firstly, the linear deviation model was established. Based on the structural relationship between the tractor and the trailed agricultural implements, the overall kinematics model of the vehicle was established by considering the four degrees of freedom of the vehicle: transverse, longitudinal, heading and articulation angle, ignoring the lateral force of the vehicle and the slip in the forward process. The geometric relationship between the vehicle and the reference path was integrated to establish the linear deviation model of vehicle-road based on the vehicle kinematic model and an approximate linearization method. Then, the control algorithm was designed. The switching function was designed considering three evaluation indexes: lateral deviation, course deviation and hinged angle deviation. The exponential reaching law was used as the reaching mode, the saturation function was used instead of the sign function to reduce the control variable jitter, and the convergence of the control law was verified by combining the Lyapunov function. The system was three-dimensional, in order to improve the dynamic response and steady-state characteristics of the system, the two conjugate dominant poles of the system were assigned within the required range, and the third point was kept away from the two dominant poles to reduce the interference on the system performance. The coefficient matrix of the switching function was solved based on the Ackermann formula, then the calculation formula of the tractor front wheel angle was obtained, and the whole control algorithm was designed. Finally, the path tracking control simulation experiment was carried out. The sliding mode controller was built in the MATLAB/Simulink environment, the controller was composed of the deviation calculation module and the control output calculation module. The tractor-implement model in Carsim software was selected with the front car as a tractor and the rear car as the single-axle implement, and tracking control simulation tests of different reference paths were conducted in the MATLAB/Carsim co-simulation environment. [Results and Discussions] Based on the co-simulation environment, the tracking simulation experiments of three reference paths were carried out. When tracking the double lane change path, the lateral deviation and heading deviation of the agricultural implement converged to 0 m and 0° after 8 s. When the reference heading changed, the lateral deviation and heading deviation were less than 0.1 m and less than 7°. When tracking the circular reference path, the lateral deviation of agricultural machinery tended to be stable after 7 s and was always less than 0.03 m, and the heading deviation of agricultural machinery tended to be stable after 7 s and remained at 0°. The simulation results of the double lane change path and the circular path showed that the controller could maintain good performance when tracking the constant curvature reference path. When tracking the reference path of the S-shaped curve, the tracking performance of the agricultural machinery on the section with constant curvature was the same as the previous two road conditions, and the maximum lateral deviation of the agricultural machinery at the curvature change was less than 0.05 m, the controller still maintained good tracking performance when tracking the variable curvature path. [Conclusions] The sliding mode variable structure controller designed in this study can effectively track the linear and circular reference paths, and still maintain a good tracking effect when tracking the variable curvature paths. Agricultural machinery can be on-line in a short time, which meets the requirements of speediness. In the tracking simulation test, the angle of the tractor front wheel and the articulated angle between the tractor and agricultural implement are kept in a small range, which meets the needs of actual production and reduces the possibility of safety accidents. In summary, the agricultural implement can effectively track the reference path and meet the requirements of precision, rapidity and safety. The model and method proposed in this study provide a reference for the automatic navigation of tractive agricultural implement. In future research, special attention will be paid to the tracking control effect of the control algorithm in the actual field operation and under the condition of large speed changes. [ABSTRACT FROM AUTHOR]

The surrounding rock of the deep-buried chamber contains high-ground stress and initial cracks. Under a dynamic load, cracks will develop and expand, leading to the fracture and collapse of the confining pressure. Therefore, it is essential to study the failure process of fissured surrounding rock under the joint action of static stress and a dynamic load. In this paper, samples with cracks are used to simulate the defective rock mass. Similar modeling tests and numerical simulation studies were carried out to reveal the damage process of cracked deep rock mass under dynamic disturbance and investigate the impact threshold of rock mass damage under a certain level of hydrostatic pressure. The model test investigated the damage behavior for specimens with double-prefabrication cracks under pressure from a dynamic–static coupling load. The influence of the mechanisms of the angle of a crack, the initial static pressure, and impact capacity on specimen damage was analyzed. It was perceived that, with an increase in the angle of the crack, the omen of specimen damage is less obvious, and the specimen is subjected to sudden damage. On this basis, the damage process of the specimen containing prefabricated cracks under combined dynamic and static loads is realized through numerical simulation, and tests verify the accuracy of the results. The analysis allowed us to come up with a variation rule for the single-disturbance energy threshold for specimens with a prefabricated crack angle and the initial static load level of the specimen containing double-prefabrication cracks. The study lays the foundation for the future analysis of any deep rock mass failure process under dynamic disturbance and the protection of a deeply buried chamber. [ABSTRACT FROM AUTHOR]

In this paper, a simulation test system for the working process of soft insulation is designed, using equivalent simulated ablation test methods combined with a CCD measuring system and micro electron microscope scanning technology, which can better describe the thermal properties and state of insulation after ablation. At the same time, a test plan for the opening characteristics of the insulator based on different ablation times and different opening structure sizes as the main influencing factors are designed. The experimental results show that the ablation test can well simulate the state of an actual pulse engine compartment after the ablation and the maximum relative error of the ablation rate can be controlled within 5 %. From the influence of ablation time on the opening characteristics of the insulator, it can be seen that the maximum axial deformation of the insulator is different from the relative value of the opening pressure. The radial deformation of the insulator is larger than that of the non‐ablated insulator and larger than the inner diameter of the insulator shell after ablation. From the influence of the size of the opening structure of the insulator (depth of weakening grooves) on the opening characteristics of the insulator, it can be seen that as the weakening groove depth of the compartment deepens, the original pressure change pattern disappears, and the opening pressure and opening time of the insulator decrease significantly. [ABSTRACT FROM AUTHOR]

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In order to solve the problem of distributed dynamic characteristic parameter identification of water-lubricated bearings with large length-diameter ratio under partial load, the two-point distributed dynamic model of water-lubricated bearings was established, and the identification method of distributed dynamic characteristic parameters of water-lubricated bearings was proposed. Through simulation test, the accuracy of distributed dynamic characteristic parameter identification of bearings was analyzed by introducing load and displacement signal disturbance, and the distributed dynamic characteristic test of water-lubricated bearings with eccentric load was carried out. The results show that as the excitation force amplitude disturbance increases, the identification error of stiffness and damping coefficients increases linearly. The excitation force phase disturbance has a small impact on the stiffness coefficient, but a significant impact on the damping coefficient. As the displacement amplitude disturbance increases, the identification error of stiffness and damping coefficients increases. The phase disturbance of the displacement signal has a smaller impact on the stiffness coefficient, but a greater impact on the damping coefficient. If the identification error of stiffness and damping is required to be less than 10%,the disturbance amplitude of dynamic load and displacement signal should be less than 10%. If the identification error of stiffness and damping is required to less than 20%,the disturbance phase disturbance deviation of these two signals should be less than 1°. [ABSTRACT FROM AUTHOR]

Aiming at the problem that the filling of seed metering device for both rice and wheat could not achieve accurate seed capsule,a seed blowing device based on accurate counting was designed. According to the horizontal throwing trajectory and Venturi principle, the rice and wheat detection and seed blowing device were designed, respectively. The key factors affecting the seed filling performance of rice and wheat were identified according to the theoretical study. Based on CFD gas-solid coupling method, effects of structural parameters including nozzle structure, working speed and air inlet pressure on motion characteristics of seeds in the process of detection and seed blowing were analyzed. The feasibility of detection and seed blowing device was verified by simulation experiment, and the bench test was carried out to determine the delay time between grains. The results showed that the velocity distribution of type 3 nozzle tube structure at the nozzle mouth was wide, and the velocity distribution at X direction was more uniform. It was determined that the section length, width, height of nozzle tube were 18, 7, 3 mm, respectively. The air inlet pressure and working speed had a significant impact on the seed movement characteristics, and the resultant force and combining speed increased with the increase of air inlet pressure and working speed. Therefore, during rice and wheat seed metering, the better air inlet pressure was 300 Pa and the working speed was 20 r·min-1. Under this operating condition, the simulation time of seed interval was much smaller than the theoretical time. Finally, the feasibility of the detection and seed blowing device was verified. The results of the bench test showed that the qualified rate of rice and wheat were 90.7% and 93.2%, respectively, when the intergranular delay time was 12 ms, the inlet pressure was 300 Pa and the seed plate rotary speed was 20 r·min-1. The results provided reference for structural optimization design of mechanical seeding device for the rice and wheat. [ABSTRACT FROM AUTHOR]

Study region: Yangkeng watershed (E118°03 ', N24°57 '), one of the typical representative areas where Benggang occurs in southern China. Study focus: Sediment transport capacity (Tc) plays a key role in the construction of models of soil process-based erosion, and is closely related to sediment particle properties. However, few studies have been conducted on Tc using soilrock mixtures along steep slopes. This study investigated the impacts of gravel content and gravel composition on Tc using soilrock colluvial deposits in a steep flume. New hydrological insights for the region: Tc increases with the increase of gravel content and proportion of large gravel (5–10 mm), and can be simulated by slope steepness, unit flow discharge, gravel mass content and gravel composition (R2 =0.904; NSE=0.911). The mean weight diameter (MWD) can be used as a sediment characteristic parameter to simulate Tc, and the flow velocity, Reynolds number and stream power are suitable hydrodynamic parameters for predicting Tc. The new equation obtained by dimensionless analysis includes flow properties (unit flow discharge, stream power and Reynolds number) and sediment characteristics (MWD) has a good prediction effect on Tc (R2 =0.991, NSE=0.990), and the simulation accuracy is greater than that of other Tc equations deduced in this study. These results promote understanding of the relationship between Tc and sediment characteristics and contribute to further elucidating the erosion process of soilrock mixtures.

Copyright of Coal Geology & Exploration is the property of Xian Research Institute of China Coal Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to investigate the driving characteristics of multi-axis special vehicle under the limit condition of missing tires, a five-axis special vehicle dynamics simulation test model including vehicle parameters, power transmission and braking system, axle and suspension system, steering system, and tire system was established based on the vehicle dynamics software TruckSim. Focusing on the analysis of the effect of tire deficiency and based on the tire six component test, the simulation test model of tire parameter was modified and the 0—80—0 km/h linear acceleration brake comfort simulation test and double line operating stability simulation test were conducted to study the smooth features and stability characteristics under the condition of tire deficiency at different positions. Based on the deviation of the centroid of the vehicle, the maximum number of missing tires at different driving speeds was analyzed, and the tire layout methods as well as the degree of influence of each axle tire on the vehicle at different driving speeds were proposed. The results show that the multi-axle special vehicle has the limit condition of driving under the condition of tire deficiency, and the tire deficiency at different positions has little effect on the driving speed of the vehicle. The influence of each axle tire on the driving of this type of vehicle is ranked in order of importance, which are the first axle, the fifth axle, the third axle, the second axle, and the fourth axle. When the vehicle travels at 50 km/h, 30 km/h, and 20 km/h, the maximum numbers of missing tires are 1, 2, and 3, respectively. This paper can provide theoretical support for the assessment of driving safety of multi-axle special vehicles.

In the actual working process of the motor, there will be short-term overload conditions, which puts forward higher requirements for maintaining the overload capacity of the motor. Due to the limitation of the thermal limit on the overload capacity of the motor, taking a 250kW permanent magnet synchronous motor (PMSM) as an example, this paper proposes a thermal management scheme of companion-type direct cooling, and establishes a three-dimensional thermal network model considering the secondary circulation factor. At the same time, in order to explore the influence of the thermal management scheme on the overload capacity of the motor when there is an impact load, on the premise that there is a safety margin for the hottest spot temperature of the winding under the rated state of the motor, the impact load is simulated by setting the overload torque, the thermal network model is used to compare and analyze the temperature field of the motor based on the companion-type direct cooling and the indirect casing cooling, and combining with the insulation limit to quantitatively compare the overload capacity of the motor after impact load. Through the simulation test, it is verified that the motor based on the companion-type direct cooling has efficient heat dissipation and stronger impact-resistance overload capability. The proposal of the companion-type direct cooling scheme has important practical significance for excavating the load potential of the motor under actual operating conditions.

The traditional model sets the driver response time as fixed value, and the driver difference is ignored, which can lead to the error of collision warning. To optimize the problem, a safe distance model was proposed with considering the driver difference. The three factors of driver's driving age, driving style and speed were selected as characteristic values, and the response time of the driver was calculated by fuzzy control algorithm. Based on Honda model, a safe distance model considering the driver difference was established. According to the China-new car assessment program (C-NCAP), the braking condition of the front car was selected to carry out the simulation test for verifying the proposed safe distance model. The results show that the proposed model has good real-time performance and adaptability under the above conditions. The safe distance model not only ensures the driving safety, but also the response time of the driver can reflect the differences of different types of drivers to improve the driving safety. [ABSTRACT FROM AUTHOR]

To investigate the impact of different cutter structures on the crushing effect of forage stalks at various rotational speeds, this study designed five types of crushing cutters. The effects of cutter structure and rotational speed on the crushing effect of the forage crusher were examined using the discrete element method, a single-factor test. An orthogonal test was conducted, with the percentage of bond breakage as the evaluation index, and tool type and tool speed as influencing factors. The results of the orthogonal test were analyzed using range analysis. The findings revealed that the quality of alfalfa stalk crushing varied depending on the crushing structure and rotational speed. Within a certain rotational speed range, the crushing effect improved as the rotational speed increased. However, beyond a certain value, the improvement in the crushing effect became slower. Notably, the hob-type crushing structure exhibited the best crushing effect at 2400 r/min.