The United Arab Emirates (UAE) relies on groundwater as well as desalinated water which are very expensive and energy-concentrated. Despite the lack of water resources, only 54% of wastewater was recycled in the UAE in 2016. In this study, a Sustainable Farming Compartment (SFC) with an evaporative cooling system is investigated as an alternative to reusing wastewater and the optimal design is identified experimentally and numerically. First, the applicability of the SFC was examined to reduce the ambient temperature in the system. A prototype SFC was tested in the environmentally constrained laboratory and field site considering an extreme climate condition (with high temperature and humidity) in Abu Dhabi to evaluate the temperature drop and humidity change of the SFC. The experimental results showed that the temperature of the SFC significantly decreases by 7–15 °C when the initial relative humidity is 50%. For validation, an energy modeling using dynamic numerical simulations was performed that shows statistically good agreement with the experimental results. Based on the parametric studies of the system components, the optimal cooling performance of the system in terms of locations of inlet and outlet, the variation of Reynolds number was evaluated. The study suggested an optimized design for the SFC with an evaporative cooling system.

Electrokinetic transport of nanoparticles in porous media is crucial for separation technologies, but the boundary-field coupling effects in three-dimensional (3D) interconnected porous spaces remain challenging to understand. Using superresolution 3D tracking of nanoparticles in interconnected cavities, we observed an unexpected disconnect between cavity escape time and directional bias as a function of electric field strength. The cavity escape times of individual nanoparticles decreased dramatically even with weak fields (2 V/cm), enhancing effective diffusion. However, directional bias was negligible at low field strengths, and became significant only for stronger fields (~7 V/cm). Simulations revealed that at low field strengths, when Brownian motion dominated the nanoparticle dynamics [Péclet number (Pe) < 0.005], the transport was stochastic with accelerated random exploration and cavity escape without directional preference, facilitated by the coordination of weak electrophoresis and electroosmotic (EO) recirculating flow. The combined effect creates localized vortices that position particles closer to internal boundaries, increasing exit encounter probability. At larger Pe values, electrophoretic forces start to overcome the apparently random motion, and establish a preferred migration direction through the porous network. These findings demonstrate the delicate balance between Brownian fluctuations, electrophoretic force, and EO flow in interface-confined and interconnected environments, providing mechanistic insights for optimizing electrokinetic separation in chromatographic columns, separation membranes, and nanocargo delivery systems.

Direct numerical simulations were performed to study the effects of the domain size of a minimal flow unit (MFU) and its inherent periodic boundary conditions on flow physics of a turbulent channel flow in a range of $200\le R{e}_{\tau }\le 1000$. This was accomplished by comparing turbulent statistics with those computed in sub-domains (SD) of extended domain simulations. The dimensions of the MFU and SD were matched, and SD dynamics were set to minimize artificial periodicities. Streamwise and spanwise dimensions of healthy MFUs were found to increase linearly with Reynolds number. It was also found that both MFU and SD statistics and dynamics were healthy and in good agreement. This suggests that healthy MFU dynamics represent extended-domain dynamics well up to $R{e}_{\tau }=1000$, indicating a nearly negligible effect of periodic conditions on MFUs. However, there was a small deviation within the buffer layer for the MFU at $R{e}_{\tau }=200$, which manifested in an increased mean velocity and a tail in the Q2 quadrant of the $u^{\prime }$-$v^{\prime }$ plane. Thus, it should be noted that when considering an MFU domain size, stricter criteria may need to be put in place to ensure healthy turbulent dynamics.

The rheological behaviour of dense suspensions of ideally conductive particles in the presence of both electric field and shear flow is studied using large-scale numerical simulations. Under the action of an electric field, these particles are known to undergo dipolophoresis (DIP), which is the combination of two nonlinear electrokinetic phenomena: induced-charge electrophoresis (ICEP) and dielectrophoresis (DEP). For ideally conductive particles, ICEP is predominant over DEP, resulting in transient pairing dynamics. The shear viscosity and first and second normal stress differences $N_1$ and $N_2$ of such suspensions are examined over a range of volume fractions $15\,\% \leq \phi \leq 50\,\%$ as a function of Mason number $Mn$ , which measures the relative importance of viscous shear stress over electrokinetic-driven stress. For $Mn < 1$ or low shear rates, the DIP is shown to dominate the dynamics, resulting in a relatively low-viscosity state. The positive $N_1$ and negative $N_2$ are observed at $\phi < 30\,\%$ , which is similar to Brownian suspensions, while their signs are reversed at $\phi \ge 30\,\%$ . For $Mn \ge 1$ , the shear thickening starts to arise at $\phi \ge 30\,\%$ , and an almost five-fold increase in viscosity occurs at $\phi = 50\,\%$ . Both $N_1$ and $N_2$ are negative for $Mn \gg 1$ at all volume fractions considered. We illuminate the transition in rheological behaviours from DIP to shear dominance around $Mn = 1$ in connection to suspension microstructure and dynamics. Lastly, our findings reveal the potential use of nonlinear electrokinetics as a means of active rheology control for such suspensions.

Atherosclerosis is one of the most serious cardiovascular diseases that are present in mid-size and large-size arteries. Typically, it involves geometry of narrowing the arteries and hardening of the vessel wall due to the deposition of plaque. It is also known that it is primarily a progressive inflammatory disease initiated by a localized accumulation of low-density lipid (LDL)