Increased capacity, higher data rate, decreased latency, and better service quality are examples of the primary objectives or needs that must be catered to in the near future, i.e., fifth-generation (5G) and beyond. To fulfil these needs, cellular network design must be drastically improved. The 5G cellular network design, huge multiple-input multiple-output (MIMO) technology, and device-to-device communication are all highlighted in this comprehensive study. Hence, free-space optics (FSO) is a promising solution to address this field. However, FSO standalone is insufficient during turbulent weather conditions. FSO systems possess some limitations, such as being able to be disturbed by any interference between sender and receiver such as a flying bird and a tree, as it requires line-of-sight (LOS) connectivity. Moreover, it is sensitive to weather conditions; the FSO performance significantly decreases in bad weather conditions such as fog and snow; those factors deteriorate the performance of FSO. This paper conducts a systematic survey on the existing projects in the same area of research such as the hybrid FSO/Radio frequency (RF) communication system by listing each technique used for each model to achieve optimum performance in terms of data rate and Bit Error Rate (BER) to be implemented in 5G networks.

Joint effects of aperture averaging and beam width on the performance of free-space optical communication links, under the impairments of atmospheric loss, turbulence, and pointing errors (PEs), are investigated from an information theory perspective. The propagation of a spatially partially coherent Gaussian-beam wave through a random turbulent medium is characterized, taking into account the diverging and focusing properties of the optical beam as well as the scintillation and beam wander effects. Results show that a noticeable improvement in the average channel capacity can be achieved with an enlarged receiver aperture in the moderate-to-strong turbulence regime, even without knowledge of the channel state information. In particular, it is observed that the optimum beam width can be reduced to improve the channel capacity, albeit the presence of scintillation and PEs, given that either one or both of these adverse effects are least dominant. We show that, under strong turbulence conditions, the beam width increases linearly with the Rytov variance for a relatively smaller PE loss but changes exponentially with steeper increments for higher PE losses. Our findings conclude that the optimal beam width is dependent on the combined effects of turbulence and PEs, and this parameter should be adjusted according to the varying atmospheric channel conditions. Therefore, we demonstrate that the maximum channel capacity is best achieved through the introduction of a larger receiver aperture and a beam-width optimization technique.

Compact multi-rotor unmanned aerial vehicles (UAVs) can be operated in many challenging environmental conditions. In case the UAV requires certain considerations in designing like lightweight, efficient propulsion system and others depending upon the application, the hybrid UAV comes into play when the usual UAV types cannot be sufficient to meet the requirements. The propulsion system for the UAV was selected to be coaxial rotors because it has a high thrust-to-weight ratio and to increase the efficiency of the propulsion system, a unique propeller was proposed to achieve higher thrust. The proposed propeller was uniquely designed by analyzing various airfoil sections under different Reynolds’s number using X-Foil tool to obtain the optimum airfoil section for the propellers. Since the design with duct increases efficiency, the Hybrid UAV presented in this paper has the modified novel convergent–divergent (C–D)-based duct which is a simplified model of a conventional C–D duct. The yawing and rolling maneuverings of the UAV could be achieved by the thrust vectoring method so that the design is simpler from a structural and mechanical perspective. The use of UAVs has risen in recent years, especially compact UAVs, which can be applied for applications like surveillance, detection and inspection, and monitoring in a narrow region of space. The design of the UAV is modeled in CATIA, and its further performance enactment factors are picked from advanced computational simulations relayed bottom-up approach. The predominant computational fluid dynamics (CFD) and fluid structure interaction (FSI) investigations are imposed and optimized through Computational Analyses using Ansys Workbench 17.2, which includes analysis of structural behaviour of various alloys, CFRP and GFRP based composite materials. From the structural analysis Titanium alloy came out to be the best performing materials among the others by having lower total deformation and other parameters such as normal and equivalent stress. The dynamics control response is obtained using MATLAB Simulink. The validations are carried out on the propeller using a thrust stand for CFD and on the duct through a high-jet facility for structural outcomes to meet the expected outcome.

Schematic overview of the structural, electronic, optical, and thermodynamic properties of Rb ₃ SbX ₆ double perovskites for advanced optoelectronic applications.

In this study, thrust force generation during drilling in natural fiber-reinforced epoxy has been investigated. Three natural fibers Abaca (A), Hemp (H) and Jute (J) have been utilized. Four different point angles of the twisted drill tools have been employed: 90°, 100°, 105° and 118°. The sequence of natural fiber-based specimens prepared for the studies as follows: A/H/A/H and H/J/H/J. The objective of this study is to find the drilling process parameters at lower thrust force. Also find the percentage of contribution of the drilling process parameters on the thrust force. Few authors has studied the drilling analysis using angle variation in the twisted drill bit however, no researches has been found in the drilling study of Hemp, Abaca and Jute by different angled twist drill bit. The result indicates that at 0.05 mm/rev feed rate and 3000 rpm spindle speed generated minimum thrust force of 4.6 N on abaca and hemp-based composites using 90°-point angle of the twisted drill bit. At 0.05 mm/rev, 3000 rpm and 90°-point angle of drill bit, produced minimum thrust force of 3.1 N on Hemp and Jute fiber-based composite. Thermal imager has been used to monitor temperature variation during the drilling of composite specimens. Defects in the specimen was identified by using scanning electron microscopic and microscopic images. The analysis of variance of the thrust force generated during drilling of the A/H/A/H and H/J/H/J based composite materials has performed using Minitab 21 software.

The research was investigated Turkey Berries drying capability using Active Mode Indirect Solar Dryers at Kovaipudur in Coimbatore, India. The conic-shaped Thermal Energy Storage (TES) covered the solar collector selectively and photovoltaic (PV) panels used to power divergent ducts equipped with DC blowers to enhance the AMISD. An energy analysis revealed meaningful distinctions between the AMISD systems equipped with TES and those operated without TES. The implementation of Thermal Energy Storage brought about a 89.6% collector efficiency rate that exceeded the results commonly reported in related PCM-based solar drying platforms. The proposed combination of a conic-shaped PCM module and a PV-powered diverging duct serves as the main cause behind this performance gain by supporting heat retention and enhancing airflow distribution. The solar dryers achieved better overall efficiency when using TES because they reached 15.23% efficiency compared to 14.8% without TES. The TES system increased the Energy Utilization Ratio up to 29.31 from its initial value of 28. Without TES AMISD used 1384 W of energy but with the implementation of TES it only needed 1268 W to function properly. The information about energy output demonstrates TES produces maximum energy consumption efficiency both with and without Phase Change Material (PCM). The PCM integration in the Specific Collector Area (SAC) improved its energy efficiency from 6.84 to 7.1%. The Sustainability Index scores achieved 8.1 when PCM was included in the experiments while the baseline scores remained at 8.01 without PCM application. Regardless of positive findings the actual experimental data fell short of projecting greenhouse dryer service expectancy to last for 35 years. The study demonstrates that using AMISD with PCM works effectively with improved energy performance while diminishing environmental influence and decreasing operational costs. Based on present circumstances in the region Turkey Berries drying with these specifications appears feasible and sustainable.