The thermal performances based on the interaction of nanoparticles are the topic of great interest in recent years. In the current continuation, we have utilized the activation energy and thermal radiation consequences in the bioconvection flow of magnetized Oldroyd-B nanoparticles over a stretching cylinder. As a novelty, the second order slip features (Wu’s slip) and convective Nield boundary assumptions are also introduced for the flow situation. The heat performances of nanofluids are captured with an evaluation of the famous Buongiorno’s model which enables us to determine the attractive features of Brownian motion and thermophoretic diffusion. The suggested thermal system is based on the flow velocity, nanoparticles temperature, nanoparticles volume fraction and motile microorganisms. The governing flow equations for the flow problem are constituted with relevant references for which numerically solution is developed via shooting algorithm. A detailed graphically analysis for the assisted flow problem is performed in view of the involved parameters. Although some studies are available in the literature which deals with the flow of various fluids over-stretching cylinder, the phenomenon of bioconvection and other interesting features are not reported yet. Therefore, present scientific computations are performed to fill this gap and the reported results can be more useful for the enhancement of thermal extrusion processes, solar energy systems, and biofuels.

Middle Saudi Arabia has weather conditions where the temperature is high in summer with low humidity. Conventional air conditioning systems operated by a vapor compression cycle are not economical because of the high electrical power consumption. Therefore, evaporative cooling through evaporative coolers is one of the best and most economical solutions. The present study experimentally investigates the factors affecting the performance of evaporative coolers. Pad materials and airflow rate are the main variables to investigate the evaporative cooler's performance in terms of saturation effectiveness, pressure drop across the pads, and coefficient of performance (COP). Pads material are the local palm tree “Nakheel” waste that are leaflet, leaf base, bulb, and roots. The maximum COP of the cooling system in the case of bulb pad material is 80% more than that of leaflet pad material. The saturation effectiveness of the bulb pad was a maximum which is 61.93% at an airflow of 2.25 m/s, which is more than two times that of the saturation effectiveness of the leaflet pad. The pressure drop across the bulb pad is almost 2.5 times to 9.5 times than that of leaflet pad. Results show that bulb pad performance best, whereas the leaflet pad material has the lowest performance in terms of pressure drop, saturation effectiveness, and COP.