Seasonal correlation of aerosols with soil moisture, evapotranspiration, and vegetation over Pakistan using remote sensing

Aerosols have a severe impact on the Earth's climate, human health, and ecosystem. To understand the impacts of aerosols on climate, human health, and the ecosystem we must need to understand the variability of aerosols and their optical properties. Therefore, we used Aqua-MODIS retrieved aerosol optical depth (AOD) (550 nm) and Angstrom exponent (AE) (440/870) data to analyze the Spatio-temporal seasonal variability of aerosols and their relationship with different meteorological parameters over Pakistan from 2002 to 2021. High (>0.5) AOD values were observed during the summer season and low (1) in the northern regions of Pakistan indicating the dominance of fine mode particles during the winter season. Moreover, AOD showed a positive correlation with Relative Humidity (RH), Evapotranspiration, Wind speed (WS), and Temperature. On the other hand, it showed a negative correlation with Soil moisture (SM), Normalized difference vegetation index (NDVI), and precipitation over Pakistan. Therefore, considering the outcomes of this study will help policymakers to understand the spatiotemporal variability of aerosols and their seasonal correlation with different meteorological parameters. © 2023 The AuthorsNational Aeronautics and Space Administration, NASAWe acknowledged NASA for providing us with MODIS and AIRS datasets

Experimental and Theoretical Investigations of a Modified Single-Slope Solar Still with an External Solar Water Heater

One of the key impediments to the wide utilization of solar water desalination systems is limited production. Hence, this study aims at increasing the thermal performance of a single-slope solar still by increasing the surface area of evaporation and absorption exposed to sunlight. A hollow rotating cylinder was installed inside the still structure; this modified system was then joined with an outside solar water heater for productivity improvement. The obtained results show that a 0.5 rpm rotational speed ensured that the cylinder’s surface was kept wet. A mathematical model has been formulated using the finite difference method and the Fortran 90 programming language to assess the thermal performance productivity of two solar stills (conventional solar still (CSS) and modified solar still (MSS)) modelled under different conditions. The experimental and theoretical results are well agreed, with an error of 6.14%. The obtained results show that the maximum productivity recorded in July 2019 was about 11.1 L/m2 from the MSS and 2.8 L/m2 from the CSS, with an improvement rate ranging between 286% and 300% during June, July, August, and September 2019. The production cost per liter of distilled water from the modified and conventional solar stills was 0.0302 USD/L and 0.0312 USD/L, respectively, which indicates a noticeable reduction in the cost of distillate water production

Refinement of Dynamic Hunting Leadership Algorithm for Enhanced Numerical Optimization

A recently created optimization algorithm named the Dynamic Hunting Leadership (DHL) algorithm was inspired by the leadership tactics used in hunting operations. The foundation of DHL is the idea that successful leadership can significantly increase hunting endeavors. Although DHL has shown to be relatively simple and successful in tackling a variety of practical optimization issues, it has been discovered it suffers with efficiently balancing global exploration and local search phase, particularly in high-dimensional numerical problems and engineering applications. Furthermore, due to drawbacks, it is vulnerable to becoming stuck in local optimal. The present study aims to tackle the aforementioned challenges by introducing a modified variant of DHL, referred to as mDHL, that utilizes the Levy Flight technique as a localized development strategy to augment each hunter’s capacity to track their prey and attain superior optimal outcomes. Moreover, local escape operator and quasi-opposition learning are synergistically incorporated to foster the hunters’ exploration and localized optimal escape techniques. These tactics foster superior knowledge sharing between leaders and hunters, resulting in a harmonious blend of exploration and development capabilities. The mDHL algorithm is shown to outperform existing optimizers across 20 function test suites with varying dimensions from 30 to 200 and CEC 2019 functions. In addition, it has been successfully applied to solve four practical engineering design cases, demonstrating its practicality. The experimental findings indicate a substantial improvement over conventional DHL, emphasizing the potential of mDHL as a competitive and efficient algorithm for addressing engineering and numerical optimization challenges

Experimental Investigation of the Effect of a Combination of Active and Passive Cooling Mechanism on the Thermal Characteristics and Efficiency of Solar PV Module

A photovoltaic (PV) module’s electrical efficiency depends on the operating temperature of the cell. Electrical efficiency reduces with increasing PV module temperature which is one of the drawbacks of this technology. This is due to the negative temperature coefficient of a PV module which decreases its voltage significantly while the current increases slightly. This study combines both active and passive cooling mechanisms to improve the electrical output of a PV module. A heat sink made up of aluminum fins and an ultrasonic humidifier were used to cool the panel. The ultrasonic humidifier was used to generate a humid environment at the rear side of the PV module. The cooling process in the study was able to reduce the temperature of the panel averagely by 14.61 °C. This reduction led to a 6.8% improvement in the electrical efficiency of the module. The average power of 12.23 W was recorded for the cooled panel against 10.87 W for the referenced module. In terms of water consumption, a total of 1.5 L was approximately consumed during the whole experimental process due to evaporation. In effect, the proposed cooling approach was demonstrated as effective