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A Conductor on Round Core (CORC) cable wound with a high-temperature superconductor is an important cable concept for high-current density applications. It is widely used in large power systems because of its advantages of good flexibility and high engineering current density. However, the complex design structure of CORC cable makes it very difficult to understand its electromagnetic properties (such as AC loss). In particular, the different winding directions of each layer in multi-layer cable have a great influence on its electromagnetic characteristics. In this paper, the H-method is used to solve the electromagnetism and mechanics equations. The influence of the winding direction of CORC cable on its electromagnetic field distribution characteristics, AC loss, and mechanical variation under the action of external magnetic field is investigated. The AC loss study of single-layer cable reveals that when the applied magnetic field is increased from 0.01 to 0.02 and 0.03 T, the AC loss peak of the cable increases by 107 and 103 orders of magnitude, respectively, indicating that the effect of low applied magnetic field on the AC loss of the cable is more significant. For multi-layer cables, cables with opposite winding directions have a greater depth of current density penetration than cables with the same winding direction. In addition, the mechanical variations of multi-layer cables with different winding orientations are explored. The results show that the Mises stress in the cable with the same winding direction is about 32% higher than that of the cable with the opposite winding direction, which indicates that the method of winding the cable in the opposite direction between adjacent layers of tape can avoid excessive mechanical stress. [ABSTRACT FROM AUTHOR]

In order to explore the affluence of empty hole on the propagation of biasing cracks, an empty hole blasting damage model is established by comb mg ANSYS/LS-DYNA finite dement software. The equation of stress distribution n the rock mass near the empty hole is deduced theoretically, and the Influence of empty whole effect on the fracture mechanism and crack propagation is analyzed. The results show that the free surface effect of empty hole will cause the sudden Increase of impact pressure and the change of seismic velocity near the empty hole, which leads to the phenomenon of "falling" of rock at the blasting surface. The shock velocity at the back surface of the empty hole is significantly smaller than that at the front surface, which indicates that the empty hole has a good effect of pressure relief and shock reduction. By comparing the analytical solution of the impact pressure and the radius of the fracture zone with the numerical calculation results it is found that the error rate of the impact pressure is 11.81%, and the error of the rams of the fracture zone is only 9.49%, which proves the accuracy of the simulation results in this paper. [ABSTRACT FROM AUTHOR]

Smart LED illumination system can use the power from whether the photovoltaic cell or the power grid automatically based on the SOC (State Of Charge) of the photovoltaic cell. This paper proposes a feedback control of the photovoltaic cells and a dynamic control strategy for the Energy system. The dynamic control strategy is used to determine the switching state of the photovoltaic cell based on the illumination load in the past one hour and the battery capacity. These controls are manifested by experimental prototype that the control scheme is correct and effective.

In order to strictly control the solid impurity particles of the pipeline and ensure the cleanliness of the pipeline of the gas supply system, a filter is installed on the pipeline before the inlet of the equipment to ensure the normal operation of the pipeline instrumentation and compressors. Since the flow of the fluid will impact the filter screen, the impact stress of the fluid on the filter screen is worth studying. However, the structure of the filter screen is complicated, so the filter screen is simplified for research. The present study adopts the dimensionless π theorem to make the density, viscosity, flow velocity, and other factors of a gas-phase fluid and solid-phase fluid dimensionless and obtains an expression for the stress acting on a filter screen as a function of the fluid parameters. Then the numerical simulation is carried out using the finite element analysis software Fluent. By changing only the velocity of the fluid and changing only the mass flow rate of the solid impurity particles, numerical simulations show that the stress acting on the filter screen has a quadratic relation with the fluid flow velocity, the stress acting on the filter screen has a linear relation with the mass flow of the solid-phase fluid, which is consistent with the law embodied in the formula derived from the π theorem. In addition, by comparing the stress acting on the filter screen traversed by different gas phase fluid media (i.e. air, CH4, and N2) under the same fluid flow conditions, it is found that effects of stress acting on the filter screen caused by different gas phase-fluids are different. All these results agree with theoretical predictions. These laws can play a guiding role in practical engineering applications in the future. Highlights Based on the dimensionless π theory, the expression about the stress of the strainer is derived. A simplified finite element model of partial filter screen is established. Using the finite element analysis software, the stress of the filter screen is obtained by changing the flow velocity of the fluid, the mass flow of the solid impurity particles and the different gas phase fluids. The filter screen can be protected from damage by controlling the flow parameters of the fluid. [ABSTRACT FROM AUTHOR]