Vibration characteristics of frozen soil under moving track loads

Vibration due to moving traffic loads is an important factor which induces frozen soil damage; this paper analyzed these vibration characteristics of frozen soil foundation under track loads. Firstly, seismic observation array （SOA） technology was applied to monitor the three dimensional dynamic characteristics of frozen soil under movable track load in a per- mafrost region and seasonal frozen soil area. Secondly, a numerical simulation for the response of frozen soil under movable track load was performed based on finite element analysis （FEA）, The results show that dynamic characteristics of frozen soil in perpendicular and parallel direction of the track are obviously different. In the direction perpendicular to the track, the vertical acceleration amplitude had an abrupt increase in the 9-10 m from the track line. In the direction parallel to the track, the acceleration in vertical and horizontal direction had a quick attenuation compared to the other direction. Lastly, various parameters were analyzed for the purpose of controlling the dynamic response of frozen soil and the vibration attenuation in frozen soil layer.

Mechanical properties of foamed polyurethane solidified ballasted track

Foamed Polyurethane Solidified Ballasted Track(FPSBT),an innovative railway track,is formed by solidifying ballast bed with foamed polyurethane.Compared with the traditional Discrete Ballasted Track(DBT),FPSBT does not require regular maintenance such as tamping and cleaning.However,limited studies exist on the mechanical properties of FPSBT.In this study,Laboratory experiments are conducted on polyurethane samples to investigate the effects of polyurethane density on the mechanical properties of FPSBT.Furthermore,the performance of DBT and FPSBT with different polyurethane densities are compared,and the recommended polyurethane density is obtained.FPSBT exhibited negligible accumulation of deformation under cyclic loads,indicating excellent performance of FPSBT owing to the anti-deformation properties of polyurethane.Further,a track load vehicle test is conducted.FPSBT exhibited better load-transmitting ability than DBT.Finally,the construction and application of FPSBT in China are introduced.This study is expected to contribute to realizing a more extensive application of FPSBT.

Switching Control Method for Optimal State Feedback Controller of Nuclear Reactor Power System

Due to the nonlinearity of the reactor power system, the load tracking situation is closely related to the initial steady-state power and the final steady-state power after the introduction of the state feedback controller. Therefore, when the initial power and the final stable power are determined, the particle swarm optimization algorithm is used to find the optimal controller parameters to minimize the load tracking error. Since there are many combinations of initial stable power and final stable power, it is not possible to find the optimal controller parameters for all combinations, so the neural network is used to take the final stable power and the initial stable power as input, and the optimal controller parameters as the output. This method obtains the optimal state feedback controller switching control method can achieve a very excellent load tracking effect in the case of continuous power change, in the power change time point, the response is fast, in the controller parameter switching time point, the actual power does not fluctuate due to the change of controller parameters. .

Arduino-based low-cost electrical load tracking system with a long-range mesh network

A system that combines the advantage of the long-range(LoRa)communication method and the structural characteristics of a mesh network for an LoRa mesh network-based wireless electrical load tracking system is proposed.The system demonstrates considerable potential in reducing data loss due to environmental factors in farfield wireless energy monitoring.The proposed system can automatically control the function of each node by confirming the data source and eventually adjust the system structure according to real-time monitoring data without manual intervention.To further improve the sustainability of the system in outdoor environments,a standby equipment is designed to automatically ensure the normal operation of the system when the hardware of the base station fails.Our system is based on the Arduino board,which lowers the production cost and provides a simple manufacturing process.After conducting a long-term monitoring of a near-field smart manufacturing process in South Korea and the far-field energy consumption of rural households in Tanzania,we have proven that the system can be implemented in most regions,neither confined to a specific geographic location nor limited by the development of local infrastructure.This system comprises a smart framework that improves the quality of energy monitoring.Finally,the proposed big-data-technology-based power supply policy offers a new approach for prolonging the power supply time of off-grid power plants,thereby providing a guideline for more rural areas with limited power sources to utilize uninterrupted electricity.