Significant growth in solar photovoltaic (PV) installation has been observed during the last decade in standalone and grid-connected power generation systems. However, the PV system has a non-linear output characteristic because of weather intermittency, which tends to a substantial loss in overall system output. Thus, to optimize the output of the PV system, maximum power point tracking (MPPT) techniques are used to track the global maximum power point (GMPP) and extract the maximum power from the PV system under different weather conditions with better precision. Since MPPT is an essential part of the PV system, to date, many MPPT methods have been developed by various researchers, each with unique features. A Google Scholar survey of the last five years (2015–2020) was performed to investigate the number of review articles published. It was found that overall, seventy-one review articles were published on different MPPT techniques; out of those, only four were on non-uniform solar irradiance, and seven review articles included shading conditions. Unfortunately, very few attempts were made in this regard. Therefore, a comprehensive review paper on this topic is needed, in which almost all the well-known MPPT techniques should be encapsulated in one document. This article focuses on online and soft-computing MPPT algorithm classifications under non-uniform irradiance conditions along with their mathematical expression, operating principles, and block diagram/flow charts. It will provide a direction for future research and development in the field of maximum power point tracking optimization.

The phenomenon of acoustic wave reflection off fluid–solid surfaces is the focus of this research. This research aims to measure the effect of material physical qualities on oblique incidence acoustic attenuation across a large frequency range. To construct the extensive comparison shown in the supporting documentation, reflection coefficient curves were generated by carefully adjusting the porousness and permeability of the poroelastic solid. The next stage in determining its acoustic response is to determine the pseudo-Brewster angle shift and the reflection coefficient minimum dip for the previously indicated attenuation permutations. This circumstance is made possible by modeling and studying the reflection and absorption of acoustic plane waves encountering half-space and two-layer surfaces. For this purpose, both viscous and thermal losses are taken into account. According to the research findings, the propagation medium has a significant impact on the form of the curve that represents the reflection coefficient, whereas the effects of permeability, porosity, and driving frequency are relatively less significant to the pseudo-Brewster angle and curve minima, respectively. This research additionally found that as permeability and porosity increase, the pseudo-Brewster angle shifts to the left (proportionally to porosity increase) until it reaches a limiting value of 73.4 degrees, and that the reflection coefficient curves for each level of porosity exhibit a greater angular dependence, with an overall decrease in magnitude at all incident angles. These findings are given within the framework of the investigation (in proportion to the increase in porosity). The study concluded that when permeability declined, the angular dependence of frequency-dependent attenuation reduced, resulting in iso-porous curves. The study also discovered that the matrix porosity largely affected the angular dependency of the viscous losses in the range of 1.4 × 10⁻¹⁴ m² permeability.

This study aims to analyse the performance of MAPbI ₃ -based perovskite solar cells (PSCs) by integrating machine learning (ML) models with the SCAPS-1D simulator. An extensive dataset of 28,182 PSCs, combinations of six-electron transport layers, ten-hole transport layers, and MAPbI ₃ absorber layer by varying thickness of each layer, has been generated in the SCAPS-1D simulator. In this research work, among those eight ML models, the XGBoost algorithm shows high accuracy for predicting the power conversion efficiency (PCE) of the cell, achieving root mean square error (RMSE) of 0.052 and a coefficient of determination (R²) of 0.999. Using Pearson correlation and Shapley Additive Explanations (SHAP), the most effective configuration for high-performance PSCs was identified by evaluating parameter significance. SCAPS-1D simulations revealed an optimal configuration comprising 200nm WS2, 900nm MAPbI ₃ , and 500nm CBTS thin layer, achieving a PCE of 24.34%. Further adjustments in doping densities increased the PCE to 34.65%. This research highlights the critical importance of precise material and structural optimization to improve PSC performance. The integration of ML with traditional simulation techniques provides a robust foundation for PSC research, supporting further experimental validation and potential large-scale applications, ultimately advancing more efficient and durable photovoltaic technologies.

Free space optical (FSO) communication system is a promising candidate for today's era of intelligent networks for the reason that it has potential advantages such as, high data rates, large bandwidth, non-licensed spectrum, line-of-sight communication and many more. Relay-assisted communication provides an additional boost to system's performance by expanding its capacity, coverage range, enhancing data rates and mitigating the effect of turbulence. In this manuscript, three dual-hop systems are considered i.e., FSO-FSO, radio frequency (RF)-FSO and FSO-RF systems employing decode and forward (DF) relaying protocol. Furthermore, chaotic signals are incorporated in these systems to enhance their confidentiality using differential chaos shift keying (DCSK). This is demonstrated by performing secrecy analysis on the system. Here, it is assumed that RF link experiences Nakagami-m fading while the affect of fading in FSO channel is caused by Gamma-Gamma turbulence along with pointing errors. The average bit error rate (BER) of three proposed systems is analyzed, and the results indicated that the FSO-RF-DCSK system outperformed the other three in terms of performance. Finally, secrecy performance is accomplished using secrecy outage probability (SOP) as a metric for the proposed systems. The findings are noteworthy as FSO-FSO-DCSK system demonstrates superior performance as compared to FSO-RF-DCSK and RF-FSO-DCSK systems in terms of secrecy. As compared to other counterparts, FSO-FSO-DCSK system shows an improvement of more than 10 order of magnitude in terms of signal-to-noise (SNR) ratio.