Recently, solar power generation is significantly contributed to growing renewable sources of electricity all over the world. The reliability and availability improvement of solar photovoltaic (PV) systems has become a critical area of interest for researchers. Reliability, availability, and maintainability (RAM) is an engineering tool used to address operational and safety issues of systems. It aims to identify the weakest areas of a system which will improve the overall system reliability. In this paper, RAM analysis of grid-connected solar-PV system is presented. Elaborate RAM analysis of these systems is presented starting from the sub-assembly level to the subsystem level, then the overall system. Further, an improved Reliability Block Diagram is presented to estimate the RAM performance of seven practical grid-connected solar-PV systems. The required input data are obtained from worldwide databases of failures, and repair of various subassemblies comprising various meteorological conditions. A novel approach is also presented in order to estimate the best probability density function for each sub-assembly. The monitoring of the critical subassemblies of a PV system will increase the possibility not only for improving the availability of the system, but also to optimize the maintenance costs. Additionally, it will inform the operators about the status of the various subsystems of the system.

This paper illustrates the impact of wind turbine (WT) subassemblies’ availability on WTs’ performance. Complete and detailed reliability, availability, and maintainability (RAM) analysis of various subassemblies of WTs utilizing the Weibull probability density function (PDF) is also introduced. A modified dynamic important measures-based reliability and availability are presented to show the significant impact of various WT subassemblies on the overall system performance. This method is mainly utilized to rank the WT subassemblies regarding their impact on the system reliability and availability, identifying the subassemblies that the planned maintenance should focus on. Dynamic ranking of WT subassemblies is obtained to achieve the desired level of reliability and availability. The obtained results demonstrate the effectiveness and efficiency of the proposed approach that achieves the system’s secure operation and improves system reliability and availability.

In this paper, an extensive reliability analysis of wind energy conversion systems (WECS) is presented. Elaborate the analysis is presented starting from the subassembly level to the subsystem level, then the system or the overall WECS. The fault tree method with a Weibull probability distribution function is introduced as a complete model for estimating the wind turbine subassemblies’ reliability. The model was tested using a massive dataset of failure rates of various wind turbine subassemblies derived from relevant literature, comprising various operating concepts and the different climate conditions. In addition, ranking for various subassemblies of wind energy conversion systems concerning their impact on the overall system reliability is also presented in this paper to identify the weak items and subsystems. This identification guides the designers and planners in setting the appropriate maintenance strategies to increase the overall reliability of the considered systems and achieve a desired level of reliability. The results indicate that the model has practical applications for managing wind turbines, and the implementation demonstrates the proposed approach’s effectiveness and efficiency, which may significantly enhance the WECS reliability.

High voltage direct current (HVDC) systems provide important advantages; among them the ability to transmit enormous amounts of electrical power over great distances at low cost. As a result, planners of power systems consider it as a viable choice for power transmission and interconnection of asynchronous networks. Depending on HVDC grids, continental/super grids have been recently constructed to promote global economic development. The study described in the paper focuses on the behavior of a voltage sourced converter (VSC) based HVDC transmission system comprising three arms-neutral point clamped (NPC) converters interconnecting two asynchronous alternating current (AC)networks. In addition, the system components, and the vector control strategy of active/reactive powers and direct current (DC)bus voltage are simulated in MATLAB/Simulink under varying situations by adjusting the controller’s settings. The study records and analyzes AC/DC voltages and active/reactive powers at two converter stations undervarying power and voltage conditions. The results of the study provide key performance indicators, such as settling time (tsett), steady state error (SSE), overshot/undershoot (OS%/US%), and correlation factor (CF), which demonstrate the robustness of thesystem’s control.

In over 50 countries, the 2nd leading cause of death after cardiovascular disease is cancer. Indeed, the 10th most diagnosed cancer worldwide is bladder cancer, with approximately half a million new reported cases with fifty percent of deaths per year. While cancer is primarily regarded because of host genetics and environmental influences, microorganisms are linked to 20% of human cancers. The microbiota of each individual is unique, undergoing development in childhood and adulthood, inhabiting the human body in various sites exposed to the external environment, including the gastrointestinal tract, oral cavity, genitourinary tract, and skin. The composition of the urinary microbiota can act as a host protection mechanism, preventing infections when the physiological balance is maintained, or allowing infection and colonization by pathogens when the balance is disturbed by factors related to the host or the environment. It was previously assumed that healthy individuals had sterile urine using culture-based methods. However, using high-throughput DNA sequencing and improved culture techniques, numerous microorganisms are discovered in the urine of healthy persons, many of which are not detectable by standard culture techniques. So, the symbiotic relationship between humans and commensal microbiota has become a topic of interest in both basic and clinical fields all over the world. This review will discuss the epidemiology and external risk factors of bladder cancer, as well as the association between urinary microbiota and urinary tract disorders and bladder cancer, besides their role in treatment.