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There has been an increasing demand for green energy due to the negative impact of global warming on the environment and life. This has necessitated the fabrication of different semiconductor materials using various methods for solar cell and photovoltaic applications. Cadmium telluride (CdTe) is a polycrystalline thin film and has emerged as a leading material for the development of cost-effective and reliable photovoltaic systems because of its near-ideal bandgap for high photovoltaic conversion efficiency and optical absorption coefficient. The CdTe has excellent resistivities of 107-109 Ω cm, carrier densities of 109-1011 cm−3, and mobility ca. cm2 V−1 s−1. Development has been made in terms of optimizing the fabricating of CdTe thin films with efficiencies increasing above 22%. The addition of copper (Cu) doping has been used to increase the Cdte efficiency through a controlled amount of Cu employed in the annealing process. The characterization tools used to understand the structures of the fabricated CdTe solar cells are discussed and it was revealed from the Atomic Force Microscope that increasing the grain size reduces the non-radiative recombination for higher performance of the solar cell. Finally, the achievements and prospects of CdTe solar cells for future development are presented. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicles (UAVs) can be useful in many different scenarios including disaster management. UAVs can immediately reach the disaster area and collect data that can help relief and rescue activities. Nevertheless, these advantages can be further improved when multiple UAVs coordinate for data collection from different vantage points simultaneously. However, seamless, high‐bandwidth communication between UAVs is required for this coordination. Nonetheless, due to the scarcity of bandwidth, a UAV network operating on an unlicensed ISM band may not be feasible. In this article, we follow a conceptual approach in which UAVs can access the licensed spectrum opportunistically. However, it is highly likely that various UAVs may have different sets of approved channels available and are unable to coordinate. Therefore, UAVs are divided into clusters to establish coordination in this scenario based on the availability of a common channel between different UAVs. Clustering based on a single common channel may still not be practical, due to the sporadic availability of common channels that often causes reclustering. Therefore, we present a multi‐UAV clustering scheme in which clusters of UAVs are established with more common channels to prevent repeated reclustering by having one main channel and the rest as backup channels. However, this may reduce the size of the cluster which can be addressed by limiting the number of backup channels. In this article, we present two variants of the proposed scheme: Multi‐UAV clustering‐I and multi‐UAV clustering‐II. The multi‐UAV clustering‐I scheme attempts to cluster UAVs with as many common channels as possible, whereas the multi‐UAV clustering‐II scheme attempts to limit the number of common channels to two. In addition, we propose a method for choosing the main channel from the different channels, where these channels are rated on the basis of bandwidth capacity and the channel with the highest rank is selected as the main channel. The remaining and the rest of the channels are kept as a backup. Simulation results demonstrate smooth and high‐bandwidth communication among UAVs. [ABSTRACT FROM AUTHOR]

Salalah is known for its Al-Khareef unique weather that is marked by influx of tourists into the community resulting in high electrical load demand during the Al-Khareef season. This paper investigates the viability of two hybridised energy systems for application in Salalah community. The result demonstrated that the Photovoltaic, Wind and Battery combination is more cost effective in terms of energy consumption, initial cost and renewal price, in comparison to the other hybrid energy system. The Homer Pro software, return on investment and internal rate of return analysis showed that the Photovoltaic/Wind/Battery scheme commands higher economic and environmental viability, presenting the Photovoltaic, Wind and Battery scheme as a better option to meet the power demand for Salalah city. [ABSTRACT FROM AUTHOR]