With the implementation of the Internet of Things, the agricultural domain has become data-driven, allowing for well-timed and cost-effective farm management while remaining environmentally sustainable. Thus, the incorporation of Internet of Things in the agricultural domain is the need of the hour for developing countries whose gross domestic product primarily depends on the farming sector. It is worth highlighting that developing nations lack the infrastructure for precision agriculture; therefore, it has become necessary to come up with a methodological paradigm which can accommodate a complete model to connect ground sensors to the compute nodes in a cost-effective way by keeping the data processing limitations and constraints in consideration. In this regard, this review puts forward an overview of the state-of-the-art technologies deployed in precision agriculture for soil assessment and pollutant monitoring with respect to heavy metal in agricultural soil using various sensors. Secondly, this manuscript illustrates the processing of data generated from the sensors. In this regard, an optimized method of data processing derived from cloud computing has been shown, which is called edge computing. In addition to this, a new model of high-performance-based edge computing is also shown for efficient offloading of data with smooth workflow optimization. In a nutshell, this manuscript aims to open a new corridor for the farming sector in developing nations by tackling challenges and providing substantial consideration.

In various fields, including rockets, turbines, and engines, the critical role played by nozzles in achieving optimal performance is underscored. Within the domain of rocketry, particular attention is given to the weight of the nozzle, where even the slightest modifications in weight can lead to a profound impact on rocket performance. In this research, an endeavor is made to comprehensively investigate the intricate interplay of nozzle pressure ratio, nozzle thickness, and Mach number, to unveil the effects of these parameters on nozzle deformation, the development of equivalent stress, and the pivotal factor of safety. Material optimization strategies for a wide array of flow and geometrical parameters are also explored within the framework of this study. With each parameter considered at four levels, an exploration is conducted across Mach numbers of 1.5, 2.0, 2.5, and 3.0, alongside Nozzle Pressure Ratios of 2, 4, 6, and 8. The meticulous analysis of nozzle thicknesses at levels of 1 mm, 2 mm, 3 mm, and 4 mm is carried out. The computational fluid dynamics (CFD) analysis is systematically executed across all cases, with resultant pressure profiles on the internal surfaces of the nozzle serving as essential boundary conditions for static structural analysis. The presentation of findings entails a comprehensive discussion of the factor of safety values for all parameter combinations. Significantly, it is observed from our results that a direct correlation exists between nozzle thickness and factor of safety, with an increase in nozzle thickness corresponding to an enhancement in factor of safety.

In this work, we present the findings of the experimental study conducted in a rectangular duct at sonic and supersonic Mach numbers using passive control in the form of semi-circular ribs. Tests are conducted at sonic Mach number and four supersonic Mach numbers. The supersonic Mach numbers of the study are 1.5, 1.8, 2.2, and 2.5. The flow from the nozzles is discharged into the enlarged duct. The ribs are placed at 28 mm (1D), 56 mm (2D), 84 mm (3D), and 112 mm (4D) from the base to find the effect of the control mechanism on the flow field and the base pressure. The ribs of 6, 8, and 10 mm diameter are used to control the base pressure and ultimately the base drag. At Mach 2.2 and 2.5, control is not effective because the nozzles are over-expanded. These results reiterate the findings from the literature that the control is effective whether passive or active when nozzles flow under the influence of a favorable pressure gradient. The same is evident from the results at Mach 1.5 and 1.8. The NPRs at these Mach numbers are such that nozzles are under, correctly, and under expanded. When nozzles are operated for under expanded case, the control results in an increase in the base pressure when passive control is employed. These highly complex data are predicted using a single-layered neural network and a deep-layer neural network to save time and make it cost-effective, which shows that the data can be predicted with an accuracy of 0.88–0.99. The proposed models can predict the highly sensitive pressure terms for aerodynamic flows.

This paper discusses velocity distribution and base pressure control using annular ribs. The annular ribs are located in the enlarged duct. Its impact on the velocity distribution and base pressure changes from a converging nozzle at the sonic Mach number is investigated numerically using ANSYS software. The rib’s height is fixed to 3 mm while the rib’s height is varied from 1 mm to 2 mm. The simulation is performed by placing the rib at various locations in the duct namely 1D, 2D, 3D and 4D and at Nozzle Pressure Ration (NPR) varied from 1.5 to 5. The changes in base pressure (Pb) and velocity variation inside the duct are studied. The presence of rib in the duct causes disturbance in the flow field hence increases the Pb. The tendency of Pb to increase is observed as the height of the rib increases. Varying the NPR from 1.5 to 3 reduced Pb due to shock wave formation. The NPR increases with Pb as the flow undergoes under-expansion due to the expansion fan at the nozzle exit. The changes in Pb are consistent with velocity distribution inside the duct. The increase in turbulent kinetic energy is more significant due to the presence of rib, as compared to duct without rib. For lower NPR, the velocity is found to be highest at the axial direction of the duct while the highest velocity is found just ahead of the nozzle exit at higher NPR.

This paper discusses the control of base pressure by passive means, where the jet is issued from a converging nozzle at sonic Mach number under a favorable pressure gradient. The effect of employing annular ribs on the enlarged duct and its impact on the flow field, as the passive control mechanism from a converging nozzle at the sonic Mach number, is investigated numerically in this study. The velocity distribution and base pressure changes are analyzed using a numerical compressible turbulence flow model. Initially, the rib is positioned at 16 mm (1D) from the base of the duct. Later, the rib position is shifted from 1D to 2D and then to 3D and 4D. The effect of variation of the rib positions, as well as its height from 1 mm to 3 mm, keeping the width of the rib fixed to 3 mm, is studied. The nozzle pressure ratio varies from 1.5 to 5, and the rib location is 1D and 2D. The velocity variation in the duct with and without rib placement is also analyzed. The results revealed comprehensive spread observations from the positive analysis of base pressure variation in ducts with no ribs and ribs with heights of 1 mm and 2 mm. The base pressure increased significantly with increasing nozzle pressure ratio for both rib heights compared to a smooth duct. It is also deduced that the highest base pressure is achieved at an aspect ratio of 3:1 when placed at 4D.

This study investigated the pressure rise characteristics of a shock train contained within a duct representative of a supersonic combustion ramjet (scramjet) isolator. The simulated isolator consisted of a constant area (25 mm by 30 mm) rectangular duct back-pressured by a triangular-shaped wedge with a vertex angle of 60 degrees. The CFD technique is used to investigate the performance of converging-diverging (CD) nozzles at different divergence angles ranging between 5° to13.5° with constant throat diameter and the isolator. The dimensions of the CD nozzle considered were 25.9 mm and 7.7 mm inlet and throat diameters, respectively, and nozzle pressure ratio (NPR) of 9. The study aims to isolate the shock wave inside the isolator so that fuel injection can be done at a supersonic Mach number. The 3D model is created on Inventor 2022 software, with a converging angle of 20° and a converging length of 25 mm. The results showed that the diverging angle is crucial in determining the back pressure and Mach number. An increase of diverging angle by 0.1° causes flow separation at the lip of the nozzle. Thus, the optimum diverging angle of 13.5° achieves maximum velocity for a given CD nozzle geometry at specific operating conditions.