Kuvempu University

About: Kuvempu University is a education organization based out in Shimoga, India. It is known for research contribution in the topics: Cyclic voltammetry & Carbon paste electrode. The organization has 1575 authors who have published 2210 publications receiving 39755 citations. The organization is also known as: KU.

A hybrid electrochemical-thermal method for the preparation of large ZnO nanoparticles

Abstract: A simple and efficient two-step hybrid electrochemical–thermal route was developed for the synthesis of large quantity of ZnO nanoparticles using aqueous sodium bicarbonate electrolyte and sacrificial Zn anode and cathode in an undivided cell under galvanostatic mode at room temperature. The bath concentration and current density were varied from 30 to 120 mmol and 0.05 to 1.5 A/dm2. The electrochemically generated precursor was calcined for an hour at different range of temperature from 140 to 600 °C. The calcined samples were characterized by XRD, SEM/EDX, TEM, TG-DTA, FT-IR, and UV–Vis spectral methods. Rietveld refinement of X-ray data indicates that the calcined compound exhibits hexagonal (Wurtzite) structure with space group of P63mc (No. 186). The crystallite sizes were in the range of 22–75 nm based on Debye–Scherrer equation. The TEM results reveal that the particle sizes were in the order of 30–40 nm. The blue shift was noticed in UV–Vis absorption spectra, the band gaps were found to be 5.40–5.11 eV. Scanning electron micrographs suggest that all the samples were randomly oriented granular morphology.

Nonlinear convective heat and mass transfer of Oldroyd-B nanofluid over a stretching sheet in the presence of uniform heat source/sink

Abstract: The present study addresses the three-dimensional flow and nonlinear radiative heat transfer of an Oldroyd-B nanofluid flow over a stretching surface with the addition effects of uniform heat source/sink and convective boundary conditions. Suitable similarity transformations are employed to reduce the governing partial differential equations into coupled nonlinear ordinary differential equations. These nonlinear ordinary differential equations are then solved numerically by RKF-45 method. The effects of physical parameters on velocity, temperature and concentration profiles are investigated and discussed. The result reveals that the nonlinear radiation is more effective than that of linear radiation.