Studies on the Functional Properties of Titanium Dioxide Nanoparticles Distributed in Silyl-Alkyl Bridged Polyaniline-Based Nanofluids

In the present work, a new kind of nanocomposite (NC)-based solid component was prepared for formulating nanofluids (NFs). The NC comprised metal oxide (titanium dioxide, TiO2) dispersed in a conducting polymer with polyaniline (PANI) and chemically linked silyl-alkyl units in it (PSA) that were designated as T-PSA NC. The NFs with ethylene glycol (EG) as a base fluid were prepared with T-PSA NCs with various compositions of TiO2 and PSA as well for various concentrations of T-PSA NCs. The scanning electron microscopic evaluation of the NC revealed that PSA deposition on TiO2 nanoparticles (NPs) decreased particle agglomeration. The PSA coating on the TiO2 NPs did not influence the crystalline structure of the TiO2 NPs, according to the X-ray diffraction patterns. The thermophysical characterization and molecular interaction features of the NFs at 303 K including a novel inorganic-organic T-PSA NC, were detailed. Furthermore, the stability of the T-PSA NC-based NFs was investigated experimentally using the zeta potential, and the particle size distribution change was analyzed using the dynamic light scattering (DLS) method. The T-PSA NCs had particle sizes that were significantly bigger than pristine PSA and pure TiO2. Most of the preparation conditions used to produce the T-PSA NCs resulted in moderately stable suspensions in EG. The results revealed that the ultrasonic velocity increased with the increase in the concentration of T-PSA NC mass % in the NFs, the refractive index and thermal conductivity increased with the increase in the concentration, and the surface tension exhibited a linear change when the ratio of mass % concentration of the T-PSA NCs increased. The combined presence of components that synergistically contribute to the electro, thermal, optical, and rheological properties is expected to attract advanced applications for NFs.

A Bibliometric Analysis of Research and Development of Nanofluids

Nanofluid concept was defined over 28 years ago. Since then, a veritable science has been developed around this concept. From 1993 until 2020, up to 18021 articles were published in high-quality journals worldwide. The high scientific interest in nanofluids lies in their exceptional thermophysical properties and their possibilities to design more efficient processes and systems. Although the numerous articles, there is a lack of information on the scope, its social and economic impact, or its future trends. This study provides an overview through bibliometric methods that allow better knowledge of the research field. The main goal is to offer a more generalized and strategic vision to help those researchers interested in this topic with accurate information on its impact. In addition, this study helps to maximize international collaborations and provide relevant information to decision-makers. The analysis reveals that research in nanofluids in the last decade has experienced a great specialization in a wide variety of new applications, reaching more new sectors. The main research communities, the most productive authors, or the most relevant journals are some of the analyzed metrics that provide key parameters for contextualization, allowing a clear vision of the current state of the nanofluids research field.

Bioconvective Peristaltic Transport of a Nano Eyring-Powell Fluid in a Vertical Asymmetric Channel with Gyrotactic Microorganism

Peristaltic nanofluid’s flow due to the enhanced thermal performances of nanoparticles and their importance in many sectors play a vital role in medicine, cosmetics, manufacturing, and engineering processes. In this regard, the current theoretical work examines the swimming behavior of migratory gyrotactic microorganisms in a non- Newtonian blood-based nanofluid that is subjected to a magnetic field. The addition of motile microorganisms improves heat and mass transmission by stabilizing the nanoparticle suspension created by the combined actions of buoyancy force and magnetic field. This fluid pattern may display both Newtonian and non-Newtonian fluid properties. Continuity, temperature, motile microbe, momentum, and concentration equations are used in the mathematical formulation. The series solutions are found using the perturbation technique, and the leading parameters are described using graphs. Further, the impact of various physical constraints on different physiological quantities is addressed and illustrated through graphs and is pondered in detail. Bioconvection reduces the density of gyrotactic bacteria, according to the findings. Such findings are beneficial to biomedical sciences and engineering. Microorganisms are helpful in the breakdown of organic matter, the production of oxygen, and the maintenance of human health.

Rosensweig Instability Study of Iron Oxide Nano Fluid Under Uniform Magnetic Field

We report the synthesis of magnetic nanofluids and the investigations on the formation of surface instabilities of ferrofluid when exposed to a normal uniform magnetic field. Ferrofluid of iron oxide particles with an average size of 9 nm, dispersed in a kerosene base is synthesized by a well-known chemical method. The structural analysis of the nanoparticles is carried out by employing X-ray diffraction technique. Fourier Transform Infrared Spectroscopy studies revealed the chemical binding with the surfactant. The Dynamic Light Scattering studies are performed to determine the hydrodynamic size of the suspended particles. The constancy in hydrodynamic size obtained for different particle concentrations is indicative of agglomeration-free suspension. The magnetic properties have been analyzed by the Superconducting Quantum Interference Device. The magnetization measurement signifies the superparamagnetic nature of particles. The temperature-dependent relaxation studies were carried out by field cooled (FC) and zero field cooled (ZFC) moment measurements at a constant applied field. We have demonstrated the Rosensweig instability experimentally and observed the pattern transition. The surface takes on a hexagonal pattern when the applied field surpasses the critical field, which shifts to a square pattern when the applied field reaches a second threshold. The surface tension of the fluid is measured by the pendant drop method and is correlated with the results obtained through instability measurement. The magnetic concentration of the sample is determined from the Thermo gravimetric analysis.