Partial discharge (PD) is a significant concern in the operation of Rotating Machines such as generators and motors, as it can lead to insulation degradation over time, reducing the reliability and lifespan of the Machines. To monitor PD activity, coupling capacitors (CC) are widely used as sensors for online PD detection, as they can effectively capture PD pulses in high-voltage (HV) Rotating Machines. The primary objective of this research is to measure and analyze PD signals using a CC sensor for HV Rotating Machines under varying input voltages and frequencies, following the guidelines of the IEC 60270 standard and utilizing the MPD 600 device. The experimental setup includes performing insulation resistance (IR) testing, PD calibration, and PD measurement. Additionally, this paper provides a detailed study of PD signal characteristics, specifically focusing on phase-resolved partial discharge (PRPD) patterns, to understand the behavior of PD in HV Rotating Machines, enhancing fault diagnosis and preventive maintenance strategies.

Partial discharge (PD) is a critical phenomenon in electrical systems, particularly in high-voltage (HV) equipment like transformers, cables, switchgear, and Rotating Machines. In Rotating Machines such as generators and motors, PD is a significant concern as it leads to insulation degradation, potentially resulting in catastrophic failure. Effective and reliable diagnostic techniques are essential for detecting and analyzing PD to ensure the operational safety and longevity of such equipment. Various PD detection methods have been developed, including coupling capacitor (CC), high-frequency current transformer (HFCT), and ultra-high frequency (UHF) techniques, each offering unique advantages in assessing the condition of HV electrical systems. Among these, coupling capacitors have gained significant attention due to their ability to improve the accuracy, sensitivity, and efficiency of PD detection in Rotating Machines. This study focuses on the advancements in coupling capacitor-based techniques and their critical role in enhancing PD diagnostics for monitoring and maintaining high-voltage Rotating Machinery.

Aims The use of intrauterine devices (IUDs) has been one of the most effective, the safest and cost-effective methods for preventing pregnancy, for a long time. However, some complications have been reported for IUDs. The complications may be reduced by using a specific technique for placement of IUD. The objective of this study was to introduce the Rotating withdrawal technique for the first time, which was investigated to reduce the complications of IUD insertion. Materials & Methods This historical cohort study was conducted on 1199 females who referred to Sarem Medical Center for IUD insertion from 1984 to 1995. After primary examinations, IUD was inserted by Rotating withdrawal technique. The subjects were followed up for 2 years. Findings Displacement was observed just in 20 cases (1. 67%). All of them were seen in the first month after placement. For these cases, IUD insertion was done again. After the second replacement, displacement was observed in 4 cases (0. 035%) after one month. Therefore, it was recommended to them to use another preventive method. There was no pregnancy or displacement in the other cases during 2 years. Conclusion The Rotating withdrawal technique can minimize the pregnancy rate when IUD is used. In addition to the type and quality of IUD, insertion method of IUD can increase its effectiveness.

In this research, a Rotating solar still that uses external bottom reflectors was experimentally investigated. The solar still and reflectors have the capability to shift their angle with respect to the south and the reflectors have the capability to shift their angle with respect to the horizon. The experiment has been performed in both fixed and Rotating states. For the fixed state the solar still was placed toward south and the reflectors were set in such a way to reflect sun rays on the bottom surface of the basin at solar noon. For Rotating state, the solar still and reflectors were set manually every half an hour in such a way to reflect sun rays on the bottom surface of the basin and the system was directed toward the sun all the time. The experiments were performed from November to December for 27 days. Sunny days results indicated that on average, distilled water gained using Rotating mode was about 64% more than the fixed mode. Both the Rotating and fixed mode yield for two cloudy days with respect to the average yield of sunny days decreased by 47 and 53%, respectively.

In this research, in order to investigate the effect of the piezoelectric patch which is used as a sensor or actuator in Rotating flexible structures such as a helicopter blade, the free vibrations of the Rotating rectangular sheet with and without the piezoelectric patch have been presented. First-order shear deformation theory is considered for plate displacement and piezoelectric field. Considering the effect of Coriolis acceleration, centrifugal acceleration and centrifugal in-plane forces, the equations of motion are derived from Hamilton's principle and the electromechanical couple equation is obtained from Maxwell's equation. For piezoelectric, two electrical conditions, open circuit and closed circuit, which are used in sensors and actuators, respectively, have been considered. The equations are discretized with the help of the numerical method of generalized differential squares and the matrices of inertia mass, eccentricity, Coriolis and stiffness matrix are obtained. Natural frequency values for beam and Rotating plate have been compared in Abaqus software. Also, the values obtained from the numerical solution in MATLAB have been verified with articles and ABAQUS, which have high accuracy. The effect of parameters such as hub radius, rotation speed, sheet thickness, aspect ratio, piezoelectric patch thickness and applied voltage on the natural frequency of the system has also been investigated.