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In this work, we investigate rate-splitting multiple access (RSMA) for a multiuser downlink wireless network consisting of an unmanned aerial vehicle (UAV)-assisted base station (BS) that serves multiple ground users (GUs) simultaneously. Considering two different transmission regimes, namely infinite blocklength (IBL), and finite blocklength (FBL), we analyze the performance of the considered network under the effect of imperfections in channel state information (CSI) estimation and successive interference cancellation (SIC) with the probabilistic line of sight fading channels. For IBL transmission, we derive the closed-form expressions of the outage probability, throughput, and achievable ergodic rate at each GU. Furthermore, for short packet communication, the closed-form expressions of block error rate (BLER), goodput, and achievable ergodic rate are determined with FBL transmission. Moreover, for the FBL regime we also formulate an optimization problem that jointly optimizes the 3D-position of the UAV, power allocated to each user, and common rate distribution at each user to maximize the ergodic sum rate subject to the practical constraints such as maximum tolerable BLER, minimum private and total rate at each user. We then propose an alternating optimization-based iterative algorithm to solve the problem. Monte-Carlo simulations are used to verify the accuracy of derived analytical results and demonstrate the trade-off between transmit power and achievable BLER. In addition to this, the effectiveness of RSMA in UAV-assisted communication under IBL and FBL transmission regimes is also observed compared to non-orthogonal multiple access.

This work investigates the performance of a downlink wireless network consisting of an unmanned aerial vehicle (UAV)-assisted base station (BS) that uses rate-splitting multiple access (RSMA) to serve multiple ground users (GUs) simultaneously. We analyze the network performance by deriving the closed-form expression of achievable ergodic capacity at each user. In addition to this, we maximize the ergodic capacity of the private message while guaranteeing the desired capacity of the common message. Moreover, we formulate an optimization problem to show that hovering the UAV at a certain optimal position can result in maximizing the sum capacity of the network. Monte-Carlo simulations are used to verify the accuracy of derived analytical expressions.

Exposure of mechanical stress due to different spray components can cause permanent damage to biopesticide containing Bacillus thuringiensismicrobes. The study was conducted to investigate the effect of spray operating parameters on the viability of biopesticide suspension containing B. thuringiensis. Water solution containing biopesticide B. thuringiensiswith concentration of 5 × 103ppm (v/v) was prepared (BBP suspension) and passed through three different sizes of hollow cone spray nozzles (1.14, 2.35 and 3.56 mm in diameter) at four levels of operating pressures (145, 245, 345 and 445 kPa) through a triplex piston pump for three levels of pumping periods of 10, 20 and 30 min. It was observed that the viability of the biopesticide strain decreased significantly (p< 0.001) with increase in operating pressure, decrease in nozzle size and increase in length of pumping period due to stress developed by spraying components such as pump, valve, delivery line and nozzles. The study recommended that application of biopesticides may be delivered through nozzle with larger orifice size (3.56 mm) at low operating pressure (145 kPa) for getting maximum viability of the biopesticide. The research results can provide guidance for spraying bio-pesticides in foliar application through existing spraying system.

In ground air heat exchanger (GAHE) system, the heat transfer between air and underground soil largely depends on soil thermal properties and therefore, any improvement in soil thermal properties will shorten the pipe length required and the land area needed for its installation. The objective of the present study is to investigate the effect of different backfilling materials (low cost and locally available) on the thermal performance of GAHE system using a small-scale laboratory experimental setup. Seven different backfilling materials have been considered for the study and it was observed that after 6 h of continuous operation, the drop in air temperature was 6.2 °C at outlet section of pipe (2.4 m away from inlet) for the native soil. However, for sand–bentonite with graphite as a backfilling material (BFM), the drop in air temperature of 6.2 °C was obtained at a pipe length of 1.15 m only. Therefore, the use of sand–bentonite with graphite as a BFM reduces the pipe length of GAHE system by more than 50%. The study establishes the fact that the length of pipe and land area requirement for GAHE system can be substantially reduced by using thermally enhanced backfilling materials at the close vicinity of GAHE pipes.