Gulbarga University

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.

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.

Reduced graphene oxide (rGO)-incorporated Dy-doped Cu-Zn spinel ferrite nanocomposites, (x)rGO + (1- x) Cu 0.5 Zn 0.5 Dy 0.02 Fe 1.98 O 4 (x = 0.25-1), were synthesized via a solution combustion route using urea-glucose fuels, combined with an eco-friendly sucrose-derived rGO process. Rietveld-refined X-ray diffraction confirms a predominant Imma spinel ferrite phase with only trace CuO (<= 2-3 wt%), which does not significantly influence the functional properties. Progressive rGO incorporation induces crystallite size refinement (approximate to 32.8 -> 26.9 nm), increased lattice microstrain (approximate to 2.1 -> 3.0 & times; 10 -3 ), and slight unit-cell expansion, reflecting graphene-mediated growth inhibition and interfacial strain. SEM reveals a microstructural transition from ferrite-rich agglomerates at low rGO content to graphene-dominated layered networks at x = 1.0, while EDS confirms homogeneous elemental distribution with increasing carbon fraction. Raman spectroscopy evidences systematic evolution of graphene disorder and sp 2 domain size, with I(D)/I(G) ratios decreasing from 6.2 (rGO-0.25) to a minimum of 3.8 (rGO-0.5), followed by a slight increase at higher rGO loadings, indicating an optimal balance between graphitic ordering and interfacial defect density at intermediate composition. Time-dependent UV-Vis diffuse reflectance spectroscopy, employed as a qualitative probe, reveals modest composition-dependent band-gap modulation associated with size refinement and ferrite-rGO interfacial electronic interactions, rather than absolute intrinsic optical transitions. Magnetically, all samples exhibit soft ferrimagnetic behavior. Saturation and remanent magnetization decrease monotonically with rGO content due to magnetic dilution, reduced crystallite size, and surface spin canting. Coercivity remains low up to x = 0.75 but increases at x = 1.0, primarily due to graphene-induced interfacial pinning and enhanced magnetic disorder; Dy 3+ is considered a secondary, indirect contributor. First-order reversal curve (FORC) analysis reveals a clear transition from coherent pseudo-single-domain reversal at low rGO content to interaction-dominated, diffuse, and superparamagnetic-like behavior at high rGO loading. Humidity sensing studies show a monotonic decrease in resistance with relative humidity for all composites. The rGO-0.5 composition exhibits the highest normalized resistance modulation and suitable baseline resistance, arising from an optimal balance between ferrite-derived hydrophilic adsorption sites and rGO-mediated electronic percolation pathways. In contrast, pure rGO shows negligible humidity response due to its highly reduced surface chemistry and limited functional groups.

Workplace health and safety measures play a vital role in protecting employees from occupational hazards and promoting their overall well-being. The present study examines employees’ perceptions of workplace health and safety measures in the sugar industry. The study is based on primary data collected from 100 employees through a structured questionnaire. Descriptive statistics, correlation analysis and regression analysis were used to analyze the data. The findings reveal that employees generally hold favorable opinions regarding the availability of clean drinking water, sanitation facilities, waste disposal arrangements, ventilation standards, fire-fighting equipment, first aid facilities, and machinery safeguards. The correlation analysis indicates a strong positive relationship between workplace health and safety measures, while the regression analysis confirms that these measures significantly influence employees’ perceptions of workplace safety. The study concludes that effective implementation of health and safety measures contributes significantly to employee well-being, workplace safety, and organizational productivity. Appropriate recommendations are suggested to further strengthen occupational health and safety practices in the sugar industry.