Mohamed M. Awad’s research while affiliated with Mansoura University and other places

Water scarcity is currently a major worldwide issue, and many unconventional solutions are being tested to provide water to populations in remote areas. A promising method involves harvesting water from ambient air using a humidity adsorbent and solar energy. This approach was explored through a desiccant-based solar still, using river sand impregnated with a calcium chloride solution. The sorption-desorption stability of the bed sorbent was studied over five consecutive days. Absorption occurred at night, allowing the bed to capture water vapor from the surrounding air. Various parameters that influenced the kinetics of water vapor absorption were studied. The results showed that the bed could harvest 671.02 ml m⁻² of water vapor from the ambient air at an average ambient temperature of 25 °C and an average relative humidity of 80%. The daytime process involved simultaneous desiccant regeneration and water vapor condensation. Several parameters were recorded during the trials to evaluate their influence on the evaporation rate and collected condensate. Experimental findings showed that the total amount of evaporated water is affected by the initial desiccant concentration in the bed and the cumulative solar energy. Optimal conditions yielded 908.67 ml m⁻² of evaporated water at an initial desiccant concentration of 50% and 25.47 MJ m⁻² of solar energy. The water yield ranged from 561.51 ml m⁻² to 645.39 ml m⁻², with a maximum energy efficiency of 24.60%. The estimated cost of collected water was $0.086 per liter, with a payback period of 18.25 months.

This study delves into the complex flow dynamics of magnetized bioconvective Ellis nanofluids, highlighting the critical roles of viscous dissipation and activation energy. By employing a MATLAB solver to tackle the boundary value problem, the research offers a thorough exploration of how these factors, along with oxytactic microorganism's mobility, shape fluid behavior in magnetized systems. Our findings demonstrate that an increase in the magnetization factor () leads to a decrease in both velocity and temperature due to enhanced interparticle resistance from the Lorentz force. Additionally, streamline analysis reveals that higher mixed convection parameters (ℵ) intensify flow concentration near surfaces, while increased slip parameters reduce shear stress and boundary layer thickness. Although isotherm analysis shows that higher Ellis fluid parameters enhance heat conduction, with greater porosity values promoting efficient thermal dissipation. These insights significantly advance our understanding of nanofluid dynamics, with promising implications for bioengineering and materials science, setting the stage for future research in this field.

Green hydrogen production powered by renewable energy sources is critical to the global transition to sustainable energy and net-zero emissions economies. The current study explores the multifaceted potential of green hydrogen as a key player in creating a sustainable and carbon-neutral energy landscape for electricity production under five different renewable-based configurations. This study aims to provide a complete assessment (energy, exergy, economic, and enviroeconomic) of all-day clean electricity generation systems containing integrated green hydrogen systems, comprising Polymer Electrolyte Membrane (PEM) water electrolyzers and fuel cells and using several different clean power sources, such as Photovoltaic (PV) and Photovoltaic/Thermal (PVT) solar collectors and Wind Turbines (WT). The main studied system configurations include: i) PV-Electrolyzer-Fuel cell, ii) PVT-Electrolyzer-Fuel cell, iii) WT-Electrolyzer-Fuel cell, iv) hybrid (PV + WT and PVT + WT)-Electrolyzer-Fuel cell. A MATLAB/Simulink code has been built to simulate these systems under the climatic conditions of two solar and wind-dominant locations in Egypt. The results revealed that the required amount of electricity to produce hydrogen ranges from 56.17 kWh/kg H2 to 56.87 kWh/kg H2. The total energy and exergy efficiencies are up to 35% and 17%, respectively. Moreover, the minimum values of LCOE, LCOH, and LCOE FC are 0.028 $/kWh, 2.84$/kg, and 0.253 $/kWh. Finally, the total amount of carbon dioxide mitigation is calculated. Nomenclature A Area (m 2) E Energy (J) Ė x Exergy (W) G Solar irradiation (W/m 2)

This article presents a comprehensive numerical analysis of the effects of cooling a cylinder using an eccentric slot jet impingement cooling (SJIC). The study focuses on examining the thermal and fluid behavior when the slot jet is offcenter, during impingement cooling. Several turbulence models from the k-e and k-x families were compared by evaluating the local Nusselt number profiles at different locations around the cylinder, and these results were compared to experimental data. The findings indicate that the SST k-x model outperforms the other turbulence models in estimating the Nusselt number in the stagnation region, while the standard k-x model shows improved performance elsewhere on the cylinder. Furthermore, this study reveals a decrease in the maximum local Nusselt number and a shift in the direction of the nozzle displacement. The presence of swirling/recirculating fluid at the trailing end of the cylinder enhances heat transfer near the back end of the cylinder. The separation and the reattachment of the fluid stream differ depending on the Reynolds number, with low Reynolds numbers resulting in reattachment on the side of the slot jet and higher Reynolds numbers leading to reattachment in the opposite direction. Additionally, the length of the recirculation and swirling zones increases as the nozzle-to-cylinder spacing (H/S) increases. However, as the eccentricity (E/S) increases, the size of the swirl circulation zones decreases and completely vanishes for E/S ¼ 4. This study provides valuable insights for optimal cooling design.

This article presents a comprehensive numerical analysis of the effects of cooling a cylinder using an eccentric Slot Jet Impingement Cooling (SJIC). The study focuses on examining the thermal and fluid behaviour when the slot jet is off-centre, during impingement cooling. Several turbulence models from the k-e and k-ε families were compared by evaluating the local Nusselt number profiles at different locations around the cylinder, and these results were compared to experimental data. The findings indicate that the SST k-ω model outperforms the other turbulence models in estimating the Nusselt number in the stagnation region, while the standard k-ω model shows improved performance elsewhere on the cylinder. Furthermore, this study reveals a decrease in the maximum local Nusselt number and a shift in the direction of the nozzle displacement. The presence of swirling/recirculating fluid at the trailing end of the cylinder enhances heat transfer near the back end of the cylinder. The separation and the reattachment of the fluid stream differ depending on the Reynolds number, with low Reynolds numbers resulting in reattachment on the side of the slot jet and higher Reynolds numbers leading to reattachment in the opposite direction. Additionally, the length of the recirculation and swirling zones increases as the nozzle-to-cylinder spacing (H/S) increases. However, as the eccentricity (E/S) increases, the size of the swirl circulation zones decreases and completely vanishes for E/S = 4. This study provides valuable insights for optimal cooling design.