Davangere University is a public state university located in Davangere, Karnataka, India. The university was established in the year 2008 by the Government of Karnataka.
The linear instability of double-diffusive convection in a viscoelastic fluid, described by the Navier-Stokes-Voigt (NSV) model, is investigated. The effects of viscoelasticity and diffusive transport parameters on the onset of convection are analyzed for rigid-free, free-free, and rigid-rigid boundary configurations. The stability eigenvalue problem is solved numerically using the Galerkin method and validated against available analytical and numerical results. The analysis shows that viscoelasticity does not influence stationary convection but significantly affects oscillatory instability. The Voigt parameter alters the balance between viscous dissipation, elastic relaxation, and solutal buoyancy. This leads to a decrease in the critical Rayleigh number for small values of the Voigt parameter and an increase for larger values due to dominant viscoelastic damping. A clear stability hierarchy is observed among the boundary configurations: free-free boundaries are the least stable, while rigid-rigid boundaries are the most stable. Increasing the solutal Rayleigh number promotes oscillatory modes and mode transitions. The Prandtl number and Lewis number modify instability thresholds through their influence on thermal and solutal diffusion. Streamline and isotherm patterns at the critical state reveal complex convective structures. These results provide insight into the interaction between viscoelastic stresses and double-diffusive transport, and are relevant to geophysical and industrial processes involving coupled heat and mass transfer.
Vanadium pentoxide (V2O5), nickel oxide (NiO), and V2O5/NiO nanocomposites (NCs) with molar ratios of 1 : 0.5, 1 : 1, and 1 : 1.5 were synthesized by a solution-combustion (SC) method and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). Electrochemical properties were examined in a 1 M KOH electrolyte through cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge (GCD) using two electrode types: a carbon-paste electrode (CPE) and a nickel-foam electrode (NFE). Among all compositions, the V2O5/NiO (1 : 1) NC delivered the highest specific capacitance, achieving 2367 F g-1 on the CPE and 1177 F g-1 on the NFE at 10 mV s-1, with low charge-transfer resistance and excellent cycling stability. The CPE, prepared with 70% graphite powder, 15% V2O5/NiO nanocomposite powder and 15% silicone oil, provides a three-dimensional porous architecture that allows a greater fraction of electrochemically active material to participate compared to the NFE. This architecture enhances ion diffusion, electron transport, and rate capability, demonstrating that V2O5/NiO NCs on a CPE offer a practical pathway to high-energy-density supercapacitors.
Pollutant discharge concentration is essential to many industries and environmental management. Controlling and tracking water contamination is vital to preserving water supplies and upholding ecological regulations. Therefore, the objective of the present study is to examine the influences of waste discharge concentration, heat source/sink, inclined magnetic field, and thermophoretic particle deposition on Casson fluid flow via a flat plate with Blasius and Sakiadis flows. The system of PDEs (partial differential equations) is altered into ODEs (ordinary differential equations) by applying a suitable similarity transformation. The Runge-Kutta-Fehlberg-45 (RKF-45) order approach and shooting approach are applied to solve the resulting ODEs. A graphical representation will be utilized to demonstrate the consequences of several nondimensional constraints on their respective profiles. The key findings of this study demonstrate that the concentration profile will be improved by escalating the values of the external pollutant source and the external pollutant source variation constraints opposite trend is seen for the thermophoretic constraint. The Sherwood number declines by enhancing the magnetic parameters and the external pollution source variation. The minimum magnitude value of skin friction for the Casson parameter in Blasius flow is 0.3825. The maximum rate of heat and mass transfer values for Sakiadis flow is found to be 1.7180 and 2.5424 for heat source/sink and thermophoretic parameters, respectively.
Concentration, susceptibility, and specific heat are fundamental topics in thermodynamics and materials science, since they affect material responses to variations in temperature and concentration. These qualities are essential for optimizing chemical processes, engineering systems, and environmental applications that require precise control over energy transfer and reaction behavior. In combination, active and passive control strategies provide significant tools for modifying nanomaterial performance, allowing designs to efficiently govern transport processes and help to create solutions in developing technologies and healthcare applications. Inspired by these applications, this study investigates the unsteady magnetohydrodynamic flow of electrically conducting Boger fluid over a slowly rotating stretching disk under active and passive nanoparticle control, incorporating concentration susceptibility, Soret-Dufour, and specific heat effects. The governing equations are transformed into ordinary differential equations (ODEs) and solved using a Fibonacci Wavelet-based collocation technique, with validation against the Runge-Kutta-Fehlberg fourth- and fifth-order methods. The results reveal that increasing the solvent fraction enhances both radial and tangential velocity, whereas higher relaxation time and magnetic parameters suppress the flow due to viscoelastic resistance and Lorentz forces. Thermal and concentration fields are significantly influenced by thermophoresis, Brownian motion, and cross-diffusion effects, with active control yielding superior heat and mass performance compared to passive control. These findings provide deeper insights into controlled nanofluid transport relevant to thermal management and hydrogen energy systems.
In this study, a novel azo dye, 5-[(Z)-1,3-thiazol-2-yldiazenyl]quinolin-8-ol (TDQ), was synthesized and used as modifier for carbon paste electrode (CPE). TDQ modified CPE employed for the selective electrochemical detection of dopamine (DA), uric acid (UA) and paracetamol (PA) using cyclic voltammetry (CV). The TDQ was characterized by ATR-IR spectroscopy, UV-Visible, 1H-NMR, mass and elemental analysis. The TDQ/MCPE demonstrated good electrocatalytic activity for the oxidation of DA with high selectivity in the presence of UA and PA. The sensor exhibited a linear response for DA, UA and PA detection with a LOD of 6.86 µM, 10.28 µM, and 15.93 µM. LOQ of DA 21.150 µM, UA is 34.29 µM, and PA is 42.58 µM. additionally, the modified electrode showed a relative standard deviation (RSD
