Analysis of unsteady flow of blood conveying iron oxide nanoparticles on melting surface due to free convection using Casson model

Iron oxide nanoparticles have great importance in future biomedical applications because of their intrinsic properties, such as low toxicity, colloidal stability, and surface engineering capability. So, blood containing iron oxide nanoparticles are used in biomedical sciences as contrast agents following intravenous administration. The current problem deals with an analysis of the melting heat transfer of blood consisting iron nanoparticles in the existence of free convection. The principal equations of the problem are extremely nonlinear partial differential equations which transmute into a set of nonlinear ordinary differential equations by applying proper similarity transformations. The acquired similarity equalities are then solved numerically by Runge‐Kutta Felhsberg 45th‐order method. The results acquired are on the same level with past available results. Some noteworthy findings of the study are: the rate of heat transfer increases as the Casson parameter increases and also found that the temperature of the blood can be controlled by increasing or decreasing the Prandtl number. Hence, we conclude that flow and heat transfer of blood have significant clinical importance during the stages where the blood flow needs to be checked (surgery) and the heat transfer rate must be controlled (therapy).     

Larvicidal activity of green synthesized silver nanoparticles using Excoecaria agallocha L. (Euphorbiaceae) leaf extract against Aedes aegypti

Green synthesis of silver nanoparticles (AgNPs) using plant extracts has been achieved by eco‐friendly reducing and capping agents. The present study was conducted to evaluate the larvicidal efficacies of AgNPs synthesized using aqueous leaf extracts of Excoecaria agallocha against dengue vector, Aedes aegypti. The 3^rd and 4^th instar larvae of A. aegypti were exposed to various concentrations of aqueous extracts of E. agallocha, synthesized AgNPs and also crude solvent extracts (methanol and chloroform) for 24 h. The formation of AgNPs using aqueous leaf extracts was observed after 30 min with a characteristic colour change. The results recorded from UV‐Vis spectrum, XRD, FTIR, EDX, SEM and HR‐TEM were used to characterize and confirm the biosynthesis of AgNPs. The highest larvicidal efficacy of synthesized AgNPs was observed against 3^rd instar larvae at LC₅₀ 4.65 mg/L, LC₉₀ 14.17 mg/L and 4^th instar larvae with a concentration of LC₅₀ 6.10 mg/L, LC₉₀ 15.64 mg/L. A significant larvicidal activity was also observed with crude methanolic extracts against 3^rd instar larvae at a concentration LC₅₀ 41.74 mg/L, LC₉₀ 123.61 mg/L and 4^th instar larvae at a concentration of LC₅₀ 52.06 mg/L, LC₉₀ 166.40 mg/L as compared to the chloroform extract.Inspec keywords: silver, nanoparticles, nanofabrication, microorganisms, cellular biophysics, organic compounds, ultraviolet spectra, visible spectra, X‐ray diffraction, Fourier transform infrared spectra, X‐ray chemical analysis, scanning electron microscopy, transmission electron microscopyOther keywords: larvicidal activity, green synthesised silver nanoparticles, Excoecaria agallocha L. leaf extract, Aedes aegypti, plant extracts, capping agents, larvicidal efficacies, aqueous leaf extracts, excoecaria agallocha, dengue vector, Aedes aegypti, aegypti, aqueous extraction, E. agallocha, crude solvent extracts, methanol, chloroform, characteristic colour change, ultraviolet‐visible spectrum, X‐ray diffraction, Fourier‐transform infrared spectroscopy, EDX, scanning electron microscopy, high‐resolution transmission electron microscopy, AgNP biosynthesis, larvicidal efficacy, third instar larvae, instar larvae, crude methanolic extracts, chloroform extraction, time 24 h     

The analogy of nanoparticle shapes on the theory of convective heat transfer of Au–Fe3O4 Casson hybrid nanofluid

In recent times, Au nanoparticles have been commonly used for delivering the drug especially in the case of hypothermia of tumors, but low absorption of IR light does not solve destruction of tumor cells. However, nanoparticles such as Fe₃O₄ coated with Au could be used to deliver the drug to a specific spot due to applied external magnetic field. Due to these applications, boundary layer approximation is invoked to simplify the mathematical model. This paper presents the nanoparticle shape analysis and heat transfer features of the Au–Fe₃O₄–blood hybrid nanofluid flowing past a stretching surface on a magnetohydrodynamic medium. Numerical solutions of nonlinear differential equations are obtained by RKF-45 method with the help of shooting technique. The behavior of emerging parameters is described graphically for velocity and temperature profiles. It is found that the blade-shaped Au and Fe₃O₄ nanoparticles have better thermal conductance than brick, sphere, cylinder, needle, and platelet shapes. It is also observed that the Lorentz force generated due to magnetic field helps in controlling the flow and enhance the thermal conductivity of hybrid nanofluid.     

Role of mixed nanofluids on fluid flow and intensify energy transfer in a boundary layer region driven by a free convective force

This research study explores boundary layer flow and intensification of heat transfer through a porous medium accompanied by buoyant forces with the support of appended mixed nanofluids. The generated partial differentiation model is altered to a couple of the highly complicated nonlinear differentiation model by support of the similarity conversion. The resultant model is then resolved by the shooting method for finding the initial approximation and thereafter the Runge‐Kutta‐Fehlberg 45th‐order method is used to get the desired result. The energy transfer and the flow of mixed nanofluids are analyzed by considering vital factors, like convection, porous and volume fraction. The acquired results fairly agree with erstwhile published articles. The major finding is that for greater values of the volume fraction, both fluid flow and energy transfer of a mixed nanofluid will be greater when compared with a regular nanofluid.