Numerical Study of Natural Convection of Biological Nanofluid Flow Prepared from Tea Leaves under the Effect of Magnetic Field

The heat transfer of a biological nanofluid (N/F) in a rectangular cavity with two hot triangular blades is examined in this work. The properties used for nanoparticles (N/Ps) are derived from a N/P prepared naturally from tea leaves. Silver N/Ps are distributed in a 50–50 water/ethylene glycol solution. The cavity’s bottom wall is extremely hot, while the upper wall is extremely cold. The side walls are insulated, and the enclosure is surrounded by a horizontal magnetic field (M/F). The equations are solved using the control volume technique and the SIMPLE algorithm. Finally, the Nu is determined by changing the dimensions of the blade, the Rayleigh number (Ra), and the Hartmann number (Ha). Finally, a correlation is expressed for the Nu in the range of parameter changes. The results demonstrate that an increment in the Ra from 103 to 105 enhances the Nu more than 2.5 times in the absence of an M/F. An enhancement in the strength of the M/F, especially at the Ra of 105, leads to a dramatic reduction in the Nu. An increase in the height of the triangular blade intensifies the amount of Nu in weak and strong convection. The enlargement of the base of the triangular blade first enhances and then decreases as the Nu. The addition of 5% silver biological N/Ps to the fluid enhances the Nu by 13.7% in the absence of an M/F for high Ras.

Performance Enhancement of Actual Wastewater Treatment and Electricity Generation Through Surface Modified TiO2 Nanotube Arrays Based Photoanode Photocatalytic Fuel Cell

Herein, we report a surface modified TiO2 nanowire arrays (NAs) photoanode based photocatalytic fuel cell (PFC) towards simultaneous enhancement of actual wastewater treatment and electricity generation under visible light irradiation. TiO2 NAs were facile fabricated via two-step anodization process in ethylene glycol and glycerin solution, respectively. Actual wastewater samples were directly applied to evaluate the PFC performance in terms of wastewater degradation and electricity generation through the as-prepared TiO2 NAs photoanode without loading noble-metals or semiconductors. TiO2 NAs photoanode prepared from ethylene glycol solution demonstrated a highly ordered surface network, exhibiting short-circuit current density and fill factor nearly 4.3 times and 1.4 times higher than pristine TiO2 NAs photoanode prepared according to previous reports. The experimental results revealed that the fabrication of TiO2 NAs by a facile surface modification in ethylene glycol solution can be considered a low-cost and scalable routine for enhancing performance of PFC photoanode towards efficient actual wastewater treatment and electricity generation.

Purification of spent deicing fluid by membrane techniques

Membrane-based concept comprising microfiltration and nanofiltration pre-treatments, reverse osmosis pre-concentration, and membrane distillation used for final concentration was applied for producing purified and concentrated recycled deicing fluid. Additionally, a techno-economic assessment was conducted to determine the economic viability of the recycling concept. By a straightforward membrane-based concept, ∼95% of solid and colloidal impurities together with certain deicing fluid additives such as colorants and surfactants could be efficiently removed (removal efficiencies of ∼90% and ∼93%, respectively), and resulting purified deicing fluid could be concentrated to ∼60 wt% glycol solution, enabling its recycling in deicing operations. Preliminary techno-economic assessment indicated that a membrane-based concept can be used as an economically viable alternative for recycling the spent deicing fluid at airports. The techno-economic case study at an airport consuming 4,000 tonnes of deicing fluid during 6 months annually showed the concept to be economically feasible when the price of purchased propylene glycol is over 1,000 EUR/tonne. In addition to the purchase price of the propylene glycol, the most important cost factors were labor cost and the annual consumption of deicing fluid. Integrating the membrane concept with other operations at airport has potential to decrease the labor cost and further improve the economic feasibility of the concept.

A Flexible Strain Sensor Based on Embedded Ionic Liquid

We present a simple-structured strain sensor based on a low-cost ionic liquid. The ionic liquid was made of sodium chloride/propylene glycol solution and was embedded in a linear microfluidic channel fabricated using Ecoflex. The proposed sensor is capable of measuring strain up to 100% with excellent repeatability. The highest gauge factor is obtained as 6.19 under direct current excitation and 3.40 under alternating current excitation at 1 kHz. The sensor shows negligible hysteresis and overshoot, and survived 10,000 rapid stretch-release cycles of a 100% peak strain with a minor deviation in the response signal. The sensor can be mounted to different locations on the human body and suits a variety of applications in the field of motion detection, human–machine interface and healthcare monitoring.