Experimental Evaluation of Distortion Effect for Grid-Connected PV Systems with Reference to Different Types of Electric Power Quantities

Aware of the fact that the installed PV capacity and its power production rapidly increased in the last decade, with the huge impact that has been done to the power system, the distortion effects for grid-connected PV systems with reference to different types of electric power quantities will be presented in this article. The impact of the frequent fluctuation of solar irradiance on the behavior of the grid-connected PV system, due to cloud movements and resulting shadows and in terms of power quality and the evaluation of power components, is the topic of analysis in this research. Besides the simulation results of certain study cases, an experimental evaluation of electric power quantities on an actual PV system in real weather conditions was also performed. The experimental setup, formed through the combination of a PC and multifunctional I/O board with an appropriate software solution, was established and used for obtaining the target results. The methodology used for the evaluation of electric power quantities relied on the current physical components (CPC) theory for power definition. The experimental results were obtained for three different cases, namely, the low, medium, and high solar irradiance cases. On the basis of these results, the conclusions about distortion effects are given.

Endoscopic Papillary Abnormalities and Stone Recognition (EPSR) during Flexible Ureteroscopy: A Comprehensive Review

Introduction: The increasing efficiency of the different lasers and the improved performance of endoscopic devices have led to smaller stone fragments that impact the accuracy of microscopic evaluation (morphological and infrared). Before the stone destruction, the urologist has the opportunity to analyze the stone and the papillary abnormalities endoscopically (endoscopic papillary recognition (EPR) and endoscopic stone recognition (ESR)). Our objective was to evaluate the value for those endoscopic descriptions. Methods: The MEDLINE and EMBASE databases were searched in February 2021 for studies on endoscopic papillary recognition and endoscopic stone recognition. Results: If the ESR provided information concerning the main crystallization process, EPR provided information concerning the origin of the lithogenesis and its severity. Despite many actual limitations, those complementary descriptions could support the preventive care of the stone formers in improving the diagnosis of the lithogenesis mechanism and in identifying high-risk stone formers. Conclusion: Until the development of an Artificial Intelligence recognition, the endourologist has to learn EPSR to minimize the distortion effect of the new lasers on the stone analysis and to improve care efficiency of the stone formers patients.

Intrinsic and extrinsic contributions in non-linearity dielectric response of (Bi0.5Na0.3K0.2)TiO3-(Ba0.8Ca0.2)TiO3 based SrTiO3 ceramics driven by Rayleigh model

Pb-free ceramics of [(0.95-x)(Bi0.5Na0.3K0.2)TiO3-0.05(Ba0.8Ca0.2)TiO3 doped x(SrTiO3) (0.0 ≤ x ≤ 0.2) were prepared by solid solution technique. The effect of ST content on the crystal structure and morphology of the sintered ceramics were systemically investigated. Crossover phase transition from ferroelectric to relaxor accompanied by changes in the shape of grain morphology were observed by increasing ST-content. The phase crossover is caused by oxygen vacancies and 1attice distortion effect. The electrical properties for virgin and poled samples were investigated. All virgin samples belong (x ≤ 0.15) showed present ferroelectric to relaxor diffused phase transition however ST = 0.2, only relaxor to paraelectric phase transition was detected in whole range of temperature. The poled sample of ST = 0.2 showed present two phase transition similar to (ST ≤ 0.15) denote domain grow caused by domain wall displacement at high amplitude of electric field. The polarization response was studied under sub-switching cyclic of electric fie1ds at different temperatures. The non-linearity behavior showed both of ferroe1ectric and relaxor phase dominated by Rayleigh-type dynamic. The results suggest that in ferroelectric phase, the extrinsic contribution caused by domain wall motion is responsible for majority of dielectric contributions while in relaxor phase, the majority of dielectric contribution are comes from intrinsic contribution caused by lattice distortion effect. Corresponding author: [email protected]