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Nanolubricants fall among the newly evolved and emerged technologies used in lubrication and heat transfer systems due to their unique thermo-physical properties. They are crucial to the industry because they enhance surface performance, reduce maintenance and fuel costs and boost engine efficiency. They are also used in mechanical systems to efficiently minimize friction and surplus heat. The present investigation focuses to analyze Darcy–Forchheimer flow of magnetized ZnO-SAE50 nanolubricant across Riga plate. Riga plate is poised of an electromagnetic equator that consists of an everlasting magnet and a span-wise collection of irregular electrodes mounted over a planner surface and is utilized in achieving proficient flow. The flow takes place in the presence of viscous dissipation, heat source–sink and chemical reaction of higher order. Newtonian heating and thermophoretic particle deposition effects are also investigated in this study. The role of viscosity is quite important and dynamical in various engineering and industrial fields. The viscosity variation highly fluctuates the thermal systems. The present work also highlights the role of variable viscosity, owing to its importance. A novel micro-nano-convection model called the Patel model is invoked in perspective of the enhancement in thermal conductivity of nanolubricant. The use of ZnO-SAE50 nanolubricant (a brand-new form of nanolubricant) over Riga plate, variable viscosity effects and the application of Patel model are novel features of this study. The application of selected transformations causes the modeled PDEs to change into ODEs. The modeled problem is executed numerically with MATLAB bvp-4c solver. The alterations in the concerned profiles corresponding to various emerging parameters of interest are presented graphically in order to develop better understanding and make analysis. The outcomes reveal that larger modified Hartmann number significantly favors the velocity of nanolubricant ZnO-SAE50, while solid volume fraction, magnetic parameter and variable viscosity parameter halt it. The heat source–sink parameter, Eckert number and solid volume fraction are found to be helpful agents in improving temperature of nanolubricant ZnO-SAE50. In comparison with Newtonian heating (NH), common wall temperature condition (CWT) yields better thermal enhancement. The enhancing chemical reaction order ameliorates the concentration profile but it gets minified for chemical reaction parameter and thermophoresis parameter. The increasing values of magnetic parameter, variable viscosity parameter and inertial parameter tend to enhance the skin friction, while the modified Hartman number reduces it. The enhancing values of Eckert number, magnetic parameter and heat source–sink parameter increase the value of Nusselt number. [ABSTRACT FROM AUTHOR]

Study of heat and mass transfer in Maxwell fluid is carried out near a vertical plate. It is proven in many already published articles that the heat and mass transfer does not really or always follow the classical mechanics process that is known as memoryless process. Therefore, the model using classical differentiation based on the rate of change cannot really replicate such dynamical process very accurately; thus, a different concept of differentiation is needed to capture such process. Very recently, new classes of differential operators were introduced and have been recognized to be efficient in capturing processes following the power law, the decay law and the crossover behaviors. For the study of heat and mass transfer, we applied the newly introduced differential operators to model such flow. The Laplace transform, inversion algorithm and convolution theorem were used to derive the exact and semi-analytical solutions for all cases. The obtained analytical solutions were plotted for different values of fractional order α , Maxwell fluid parameter λ , thermal Grashof number Gr, mass Grashof number Gm, Prandtl number Pr and Schmidt number Sc on concentration and velocity fields. In comparison, velocity of Atangana–Baleanu fractional derivative is greater than that of Caputo and Caputo–Fabrizio for α , λ , Gr and Gm. With the increase in Pr and Sc, there is a decrease in velocity. For fractional parameter, the effect of concentration field for ABC model is more than for C and CF. Moreover, from the present solutions already published results were found as limiting cases. [ABSTRACT FROM AUTHOR]

In this paper, fabrication and characterization of Cu/PTB7-Th (35 mass%)/PC 61 BM (35 mass%)/graphene (30 mass%)/Ag thin-film composite cells are given. First of all, Ag and Cu electrodes were deposited on flat glass substrate by vacuum evaporation with 130- μ m inter-electrode gap. The PTB7-Th (35 mass%) composite and PC 61 BM (35 mass%) composite in chlorobenzene and graphene (30 mass%) were deposited on the inter-electrode gap by drop-casting technique, and film thickness of 8–12 μ m was achieved. The dependence of forward and reverse bias resistance of the cells versus temperature in the range of 25–75 ∘ C, humidity in the range of 47–90 %RH and pressure in the range of 0–7.7 kN m - 2 was measured. The average temperature resistance coefficients were equal to (− 1.03)% ∘ C - 1 and (- 1.14) % ∘ C - 1 for forward and reverse bias resistances, respectively. The reverse and forward bias resistances decreased 1.29 and 1.27 times due to % RH , and due to pressure, it decreased by 9.0–9.2%. Impedance (Z) of the sample was also measured at different frequencies (100 Hz, 1 kHz, 10 kHz and 100 kHz) which decreased from 1.23 to 1.04 times. The obtained results are explained, firstly, by transfer of charges between donors and acceptors molecules and effect of water molecules on the PTB7-Th (35 mass%):PC 61 BM (35 mass%):graphene composite. [ABSTRACT FROM AUTHOR]