نشریه مهندسی برق دریایی
پیاپی 1 (زمستان 1400)

In this paper, a unique symmetric graphene-based plasmonic nano-waveguide is proposed to guiding electromagnetic waves in the mid-infrared spectrum. The geometric structure of the waveguide consists of two symmetrical cylinders arranged around a rectangular substrate with a high refractive index. The lateral surfaces of both cylinders are covered with a graphene monolayer, and the cylinders and rectangular substrate are placed in a low refractive index environment. Here, the modal model properties of surface plasmon polaritons are investigated using the finite element method. The dependence of the propagation properties of the modes on the frequency of the incident wave, the graphene Fermi energy and the dimensions of the geometric structure of the waveguide has been calculated in detail. Due to the unique structure of the designed waveguide, the propagation length of the modes is approximately 4600 nm , the normalized mode area is ~〖10〗^(-6) and the figure of merit is nearly 500. According to the simulation results, this structure has a strong confinement the light subwavelength and high performance in the mid-infrared region for use in practical applications in photonic integrated circuits.

Given the importance of the equipment used in seaports and the development of the Global Positioning System, there is a potential for better performance in estimating line parameters. The presence of phasor measuring equipment is essential for line parameter estimation algorithms, which will increase system reliability. Today, a small number of phasors measuring equipment’s are installed in the power system and the information at both ends of a line, one through the same equipment and the other through the control and data acquisition system.In this paper, the proposed solution is first applied to a simple two-terminal transmission line and then extended to a three-terminal system. The simulation results in PSCAD software confirm the validity and correctness of the proposed method for today's power systems. The results showed that the proposed method is able to calculate the real-time parameters of the system with the appropriate accuracy for the purposes of network studies. In this research, for calculating the positive (negative) sequence parameters of the line based on the phase measurements of voltage and current at both ends of the line, it is presented. For this purpose, phase and current information of voltage and current at the beginning and end of the transmission line, resulting from multiple measurements of these parameters are used and then based on the Newton-Raphson method to select the best estimate, the transmission line parameters are determined.The obtained results show a very good correlation between the parameters obtained from the measured data and the parameters calculated by the computational software.

Control of the router's underwater remotely Operated Vehicles (ROVs) is challenging due to its highly nonlinear nature, strong coupling among variables, and unknown environment of the underwater in terms of underwater currents.The classic sliding mode controller is a popular control method in nonlinear dynamic tracking systems. However, one of the problems with this control method is chattering in its control signal. Therefore, in this study, to reduce the chattering of the control signal applied to the trusters, a Model-Free High Order- sliding mode control is proposed. in the end, the performance of the proposed controller simulated on an underwater robot. In addition, the outcomes compare with the performance of the PID controller and the traditional sliding mode controller, which results show the superiority of the proposed controller.