NP [CGG], Ratio 30-39

Nanofluid refers to the mixture of fluid and solid nanoparticles. If this mixture contains more than one NP or fluid, it is called "hybrid nanofluid"; further, if HN contains more than one NP and also more than one fluid, it is called "dihybrid nanofluid." In this research, first, titanium dioxide NP was dispersed in the water-ethylene glycol basefluid and formed an HN. Then, thermal conductivity of HN was measured. After that, MWCNT NP was added to the HN and formed a DHN. Further, TC of DHN measured. Both HN and DHN TCs were compared, and the results revealed that by adding MWCNT, thermal conductivity enhanced about 30.83% (from 25.65% of HN to 56.48% of DHN). On the other hand, to analyze the phase structure, and to observe the microstructure, X-ray diffraction analysis, energy-dispersive X-ray analysis, and field emission scanning electron microscopy were examined. The measured TC for both samples was at volume fractions up to 1.0% and temperatures up to 50 degrees C. After an experimental study, two novel correlations were calculated by the curve-fitting method for HN and DHN, individually. In the end, to predict the other Vf and temperature, an artificial neural network has been modeled for both HN and DHN.

Carbon dots (CDs) with excellent optical properties are widely used in biomedicine, fluorescence sensing, and light-emitting diodes (LEDs). However, it is still a challenge to prepare CDs that can stably emit red fluorescence in the water environment. In this study, polydopamine-encapsulated luminescent carbon dots (CDs@PDA) with an encapsulating structure were synthesized at room temperature from p-phenylenediamine-derived red-light CDs as the core and using mussel-inspired chemical properties of polydopamine (PDA). In the binary system of water:ethanol = 1: 3 (volume ratio), the as-prepared CDs@PDA had a dual emission of ultraviolet light (330 nm) and red light (640 nm) with the fluorescence quantum yields of 8.0 and 15.5%, respectively, at the same time under 285 nm light excitation. The as-prepared CDs@PDA could be directly used for fluorescence selective sensing of 4-nitrophenol (4-NP) and Fe3+ through simultaneously quenching of ultraviolet and red fluorescence based on the internal filtration effect mechanism with detection limits of 3.44 and 3.75 mu M, respectively. This research showed that PDA-coated CDs can significantly improve the photoluminescence stability of CDs with new optical features. This means that the encapsulated structure of mussel chemistry is very helpful for expanding the application range of CDs in the water environment.