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This study investigates the performance enhancement of an automotive radiator using functionalized graphene quantum dots (FGQD)-based nanosuspensions. The primary objective is to evaluate the thermal conductivity, viscosity and heat transfer performance of FGQD-water nanosuspensions at varying concentrations (0.5wt.%, 1.0wt.% and 1.5wt.%). The research is carried out in two phases. In the first phase, the synthesis of graphene quantum dots (GQD), its dispersion in water, and the subsequent characterization of thermal properties are precisely detailed. Thermophysical properties of these nanosuspensions including thermal conductivity, viscosity and density across varying flow rates and temperatures are assessed. The thermal conductivity was measured experimentally and validated using the Hamilton model, while viscosity was assessed using the Brinkman model. In the second phase of the experimentation, experimental evaluations were conducted on a HELLA 376757051 radiator, analyzing the impact of FGQD concentration on heat transfer coefficient, pressure drop and performance index at different coolant flow rates. Nanosuspensions are experimentally examined at various coolant flow rates. The research shows a significant enhancement in heat transfer coefficients when GQD are added at concentrations of 0.50wt.%, 1.00wt.% and 1.5wt.% in comparison to the regular conventional water-based coolant. The results highlighted that increased levels of GQD led to a substantial improvement in heat transfer efficiency. It is observed that the 1.5wt.% FGQD-water nanosuspension achieves a 107% increase in heat transfer coefficient. On the other hand, 0.5wt.% offers an optimal balance between heat transfer enhancement and minimal pressure drop, making it more suitable for high-flow applications. The performance index analysis confirms that FGQD-water nanosuspensions significantly improve radiator efficiency. The findings highlight the potential of FGQD as an advanced nanofluid for automotive cooling applications, offering superior thermal performance as compared to conventional coolants.

This paper reports an investigation into electrospraying a nanosuspension containing nanoparticles sized at 5 nm and suspended in a polymer grade ethylene glycol. Hence, the processing of this nanosuspension in the stable cone-jet mode having an amorphous silica powder loading of 30 wt.% is elucidated. A comparison is made with established literature on jet break-up to identify the break-up mechanism in this investigation. The ensuing electrospray characteristics for both the polymer grade ethylene glycol and the nanosuspension are also presented. Using the data of collected droplet relics together with a volume equivalence method, the generated droplet sizes are estimated for both media and are compared with the well-known theoretical expression for calculating the droplet sizes generated for that respective jet break-up regime and medium. Finally, transmission electron microscopy of the collected deposits concludes the discussion presented in this investigation.

This paper reports a study into forming a jet-on-demand to continuous microthreads by subjecting electric fields on high viscosity and low conducting media (concentrated nanosuspensions and dielectric mediums) droplets, placed on a conducting copper plate, which has a similar plate above at a distance of ~ 10 mm. The media used in this investigation has a viscosity ≫ 1000 mPa s and an electrical conductivity ≪ 10^-6 Sm_-1 and in the case of nanomaterial loading in suspension is 003E; 15 wt.%. The investigation illustrates both the ability to form jets in this configuration and the importance of the volume of media placed as a droplet which has a direct result on the formation of a jet subsequently fragmentating to droplets. At a droplet volume of < Q₀, the resting droplet when under the influence of an applied electric field deforms forming a cone, much like those referred to as the "Taylor Cones". On increasing the volume of the droplet to Q₀ and applying a voltage of ~ 4.6 kV across the plates, the apex of the cone was observed to pulsate. On further increasing the applied voltage, giving rise to an electric field strength of ~ 0.55 kV/mm, the pulsating apex stabilizes to evolve a stable jet which undergoes instabilities promoting the generation of droplets. Consequently, a fine jet-on-demand is obtained. On increasing the droplet volume to > Q₀, forms jets on both plates. The study elucidates the importance of this jetting approach for forming droplet relics containing self-assembled nanoparticles to continuous microthreads from concentrated nanosuspensions and dielectric media for forming structures by deposition that are most useful and have widespread applications in materials science and engineering. Hence, the physical behavior of this droplet deformation — jetting — forming droplets under an imposed field, outlines the discussion presented in this paper.

Efavirenz (EFV) suffers from poor aqueous solubility which results in low bioavailability of the drug. Nanocarrier-based drug delivery systems offer a suitable alternative for improving the physico-chemical properties of the drug and hence its efficacy. Nanosuspension (NS) of EFV was formulated by solvent-anti solvent precipitation method using PVP K-30 as stabilizer and sodium lauryl sulphate (SLS) as the wetting agent. Multi-level factorial design was applied to select the optimal formulation which was further characterized. The optimal batch exhibited mean particle size of 305nm and polydispersity index (PDI) of 0.345. Solid-state characterization studies of the NS conducted using scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction, and differential scanning calorimetry (DSC) revealed compatibility between the drug and the excipients and modest alteration in the crystallinity of the drug. There was progressive increase in the solubility of the drug when incorporated in NS from 17.39$\mu$g/ml to 256$\mu$g/ml. Further, drug release studies showed significantly better and controlled drug release pattern in comparison to the free drug due to the presence of nanosized particles in the formulation.