Gulbarga University

We report on physical, mechanical, optical properties and dc conductivity of (P2O5)(0.25) + (TeO2)(0.15) + (ZnO)(0.1) + (V2O5)(0.50-x) + (Fe2O3)(x); 0.05 < x < 0.30 glasses. The density is found increased monotonically from 3.2533 g/cm(3) to 3.6368 g/cm(3) and molar volume decreased from 55.151 to 47.810 cm(3)/mol indicating induced network modification due to dopant content. Making use of density and composition of the glasses in the Makishima-Mackenzie's model, various elastic moduli including hardness and fractal bond connectivity were evaluated and assessed. UV-Vis absorption spectra were measured for the wave length range 200 nm - 800 nm. Optical band gaps (E-gap), refractive index (n), molar refraction (R-m), reflection loss (R-L), molar polarizability (alpha(m)), metallization criterion (M), dielectric constant (epsilon) and optical dielectric constant (epsilon(0)) were evaluated. The obtained E-gap in the range 2.481 eV-2.865 eV and n values in the range 2.899-4.108 indicated that these glasses are useful for optoelectronic applications. The dc conductivity (sigma(dc)) measured for the temperature range 300 K-525 K was found to vary as per Mott's small polaron hopping model at high temperature and Mott's variable range hopping model at lower temperatures. At high temperature, conductivity passed through a minimum of 1.19 & times; 10(-3) (Omega m)(-1) and activation energy passed through a maximum of 0.532 eV for composition x = 0.2. This is identified to be due to mixed transition effect, MTE occuring at x = 0.2 and attributed to Anderson's localization of charges. Density of states was found to be in the range 10(21)-10(22) eV(-1) cm(-3). For the first time, MTE has been observed in phospho-tellurite glasses.

Hybrid nanofluids are opening new frontiers in thermal systems, revolutionizing drug delivery, and offering fresh hope in cancer therapy, precision in technological and medical fields. With this motive, we performed a computational study to explore the impact of non-uniform heat source on MHD flow of ZnO+ZrO2-EG hybrid nanofluid over a horizontally moving thin needle with variable thickness. The prime novelty of this work is to examine the enhanced thermal conductivity of the hybrid nanofluid by using Maxwell/Xue nanomodels in the presence of Bongiorno’s slip mechanism. The established governing flow equations were computed utilizing the bvp5c package of MATLAB software. Subsequently, we studied and visualized the effects of key variables on fluid behavior, focusing on temperature, velocity, and concentration profiles. The findings demonstrate that augmenting the nanoparticle volume fraction substantially develops the fluid's heat performance. It is shown that the dynamic relationship among thermal radiation, needle thickness, and volume fraction results in a remarkable boost in heat transfer phenomenon. Notably, the Xue nanomodel shows better heat and mass transfer capacity than the Maxwell nanomodel. Validation against prior theoretical work ensures the reliability of the current findings. The major applicability of this work can be found in production of small measuring instruments of aerodynamical systems.

Green silver nanoparticles (AgNPs) were successfully prepared by the reducing and stabilizing action of the Terminalia arjuna stem bark (TASB) extract. The formation of nanoparticles was established by the surface plasmon resonance band at 510 nm and the FTIR spectrum, which revealed phytochemical capping interactions. Electron microscopy images revealed well-dispersed spherical nanoparticles with a size range of 20–40 nm, and EDX confirmed the presence of silver as the major component. TASB-AgNPs exhibited pronounced antimicrobial, antifungal, and antioxidant activities. Against A549 lung carcinoma cells, the nanoparticles exhibited significant cytotoxicity, which was primarily due to apoptosis. DFT calculations revealed a very small HOMO-LUMO gap of 0.0331 eV, which indicated high electronic softness and good charge transfer potential. Docking analysis revealed weak but complementary interactions with BCL-2, KEAP1, and KRAS targets. Taken together, the findings suggest that TASB-AgNPs exhibit multifaceted biomedical properties due to interfacial phytochemical-nanoparticle interactions.

This paper examines radiative magnetohydrodynamic (MHD) nanofluid flow over a porous surface using the Homotopy Perturbation Method (HPM). The wall shear stress, rate of heat transfer, and rate of mass transfer can be determined directly due to the derivation of closed-form analytic formulae of the velocity, temperature, and nanoparticle concentration fields. Sensitivity analysis is performed to evaluate the influence of the governing parameters on the skin friction coefficient (Cf), Nusselt number (Nu), and Sherwood number (Sh), including the magnetic field strength (M), permeability (K), radiation parameter (Rd), Eckert number (Ec), internal heat generation (Q), thermophoresis (Nt), and Brownian motion (Nb). The results indicate that diffusion of nanoparticles is very influential in the process of mass transfer, thermal parameters largely determine heat transfer, and magnetic and porous effects determine the momentum transportation. The sensitivity indices are well examined using the analytical HPM solutions.

The mass, momentum, and heat transfer characteristics of Jeffrey, Maxwell, and Oldroyd-B hybrid nanofluid flow above a stretched surface in the presence of non-uniform heat source/sink, thermophoresis, and Brownian motion is investigated numerically. In this study, hybrid nanofluid is composed of engine oil (as base fluid) and AA7072 and AA7075 nanoparticles. The flow governing boundary layer PDEs are first transformed into nonlinear ordinary differential equations using similarity transformations, and then they are solved using the bvp5c solver of MATLAB software. The impact of various dimensionless factors on the concentration, velocity, temperature profiles and wall friction, local Sherwood and Nusselt number are computed and portrayed via plots and tables. It reveals from the results that, the Jeffrey hybrid nanofluid seems to perform better in terms of heat transmission than the Maxwell and Oldroyd-B hybrid nanofluids under action of uneven heat source effects. Thermal transfer rate of Jeffrey hybrid nanofluid is 31.04% advanced than Maxwell hybrid nanofluid.