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Response surface methodology (RSM) is used in this study to optimize the thermal characteristics of single graphene nanoplatelets and hybrid nanofluids utilizing the miscellaneous design model. The nanofluids comprise graphene nanoplatelets and graphene nanoplatelets/cellulose nanocrystal nanoparticles in the base fluid of ethylene glycol and water (60:40). Using response surface methodology (RSM) based on central composite design (CCD) and mini tab 20 standard statistical software, the impact of temperature, volume concentration, and type of nanofluid is used to construct an empirical mathematical formula. Analysis of variance (ANOVA) is applied to determine that the developed empirical mathematical analysis is relevant. For the purpose of developing the equations, 32 experiments are conducted for second-order polynomial to the specified outputs such as thermal conductivity and viscosity. Predicted estimates and the experimental data are found to be in reasonable arrangement. In additional words, the models could expect more than 85% of thermal conductivity and viscosity fluctuations of the nanofluid, indicating that the model is accurate. Optimal thermal conductivity and viscosity values are 0.4962 W/m-K and 2.6191 cP, respectively, from the results of the optimization plot. The critical parameters are 50 °C, 0.0254%, and the category factorial is GNP/CNC, and the relevant parameters are volume concentration, temperature, and kind of nanofluid. From the results plot, the composite is 0.8371. The validation results of the model during testing indicate the capability of predicting the optimal experimental conditions. [ABSTRACT FROM AUTHOR]

Graphene, with its amazing prospects and nonpareil aspects, has enticed scientists and researchers all over the globe in a significant fashion. Graphene, the super material, endlessly demonstrates some of the substantial, as well as desired, mechanical, thermal, optical, and chemical characteristics which are just about to bring about an unprecedented transformation in the science and technology field. Being derived from graphite, graphene is made of one-atom-thick, two-dimensional carbon atoms arranged in a honeycomb lattice. This Nobel-prize-winning phenomenon includes properties that may result in a new dawn of technology. Graphene, the European Union's (EU) largest pledged project, has been extensively researched since its discovery. Several stable procedures have been developed to produce graphene nanoparticles in laboratories worldwide. Consequently, miscellaneous applications and futuristic approaches in artificial intelligence (AI)-based technology, biomedical and nanomedicine, defence and tactics, desalination, and sports are ruling over the next generation's fast-paced world and are making the existing market competitive and transformative. This review sheds light upon the ideology of the preparation and versatile application of graphene and foretells the upcoming advancements of graphene nanoparticles with the challenges rearing ahead. The study also considers graphene nanoparticles' diverse fields and portends their sustainability with the possibility of their acceptance in the commercial market as well as in common usage. [ABSTRACT FROM AUTHOR]

Flat plate solar collectors can easily be termed as the most vastly studied alternative energy transforming and generating technology of the twenty-first century. As the world is racing towards the fourth industrial revolution (Industry 4.0), more and more energy is being consumed for mega projects to be materialized. Electronic devices are not only confined to conventional intermittent and costlier electric energy, but also fuel. Solar energy is now being shared to work smart devices, transform electric energy, and operate automobiles, aeronautics, water heating, and space heating. Traditional flat plate solar collectors can only occupy 50–60% of their thermal efficiency, resulting in less heat generation and a low thermal performance because of using a common absorber made of copper tubing compared to a high conductive metal sheet (copper or aluminum). To ameliorate the thermal efficiency of the solar collector, it is imperative to find a superior alternative heat exchanger that will result in improved thermal performance of the solar collector. In this study, light has been shed in terms of substituting conventional heat absorbers with crystal nano-cellulose (CNC) and a graphene hybrid. An empirical comparison has been drawn by comparing the familiar 0.3% base fluid, 0.5% graphene, and CNC separately, as well as 0.3%, 0.5% CNC, and graphene hybrids at different temperatures. Remarkably, this work has proven that a CNC and graphene hybrid fluid with a volumetric fraction of 0.5% concentration and at a high temperature of 80 °C, gave astounding results for improved thermal conductivity, viscosity, and other parameters. CNC and graphene hybrid nanofluid can be a superior substitute for a conventional base fluid, resulting in prolific thermal performance. [ABSTRACT FROM AUTHOR]