Journal of Applied Physical Science International

We investigated the bright soliton dynamics for three-dimensional system with power-law nonlinearity. Based on nonlinear Schrodinger equation and the analytical result from one-dimensional scenario of the power-law system, we derived the bright soliton solution for the system under study via the self-similar method. Our theoretical work can be used to guide experimental study of power-law nonlinear system.

n-Hexane extracts of Costus lucanusianus stem and leaves were used for corrosion inhibition of mild steel and aluminium in 1 M HCl at concentrations of 0.1 g/L, 0.2 g/L, 0.5 g/L, 0.7 g/L and 1 g/L using thermo-gravimetric analysis (303 K – 333 K). In 1g/L, n-Hexane stem extract had maximum inhibition efficiency of 85 % at 333 K and 78% at 303 K for mild steel and aluminium respectively. Addition of extracts to acid solution increased values of E_a. Positive values of ΔH indicated endothermic adsorption process. Negative values of ΔS indicated decrease in disorderliness of the system. Negative values of ΔG (-2.95 KJ/mol to -4.10 KJ/mol) indicated physisorption mechanism. The adsorption was found to obey Freundlich isotherm. GCMS analysis showed major components of the extracts labelled n-Hexane stem extract (n-HSE) and n-Hexane leave extract (n-HLE) as 2,2'-methylenebis-1H–isoindole-1,3(2H)-dione (33.29%) and triacontanoic acid methylester (61.01%) respectively. Quantum chemical calculations were performed using Density Functional Theory with complete geometry optimization for calculations of E_HOMO, E_LUMO and energy gap. The energy gaps were 3.03 eV and 5.34 eV for n-HSE and n-HLE respectively. The softness (σ) values indicated that components of n-HSE are soft molecules; and are more reactive than n-HLE. This observation was consistent with results obtained from experimental inhibition efficiencies.

The study aims to map the depth of the tantalite mineralization as well as its location around the Olorunda mining site using integrated geophysical methods. Eight (8) profiles were conducted for the magnetic survey using G-856AX proton magnetometer in E-W direction with a total of 158 data points, profile length of 190 m, 10 m station spacing, and 20 m profile spacing. Six (6) vertical electrical soundings (VES) data points were measured on the points that have high magnetic susceptibility using the Schlumberger array configuration of the electrical resistivity techniques with a spread of 100 m. The anomaly map has a range of 19nT to 78nT for the magnetic intensity which depicts the area of magnetic susceptibilities. The Reduced to equator anomaly map has a range from 16.6nT to 77.4nT for the magnetic intensity which depicts the area of magnetic susceptibility directly above the sources. The first vertical derivative (FVD) map has a range from -1.69nT to 1.89nT. The source parameter imaging depth (SPI) map has a range from 4.3 m to 20.9 m. The total gradient map has a range of from 0.31nT/m to 3.30nT/m. The elevation map has a range from 349 m to 372 m. The high magnetic areas are in the southwestern, west, central, and eastern parts of the Olorunda mining site. The resistivity values of the study area range from 121 Ώm to 2500 Ώm. The low resistivity values reveal high conductivity areas of the study area, as a result of the pegmatite rocks around the mining site. The VES reveals the depth of tantalite mineralization at 35.8m, 44.3 m, 55.1 m, 42 m, 46.5 m, and 4.18 m.

In this study, vortex evolution dynamics for coupled ultracold atomic systems is investigated. Via the variational method, we derived vortex evolution pattern showing the quasi-stable oscillation state of system under the influence of inter-component interaction. The key quasi-stable quantities like oscillation period and time-varying vortex ring radius are derived. The theoretical results derived in this work can be used to guide experimental study of vortex evolution in coupled ultracold atomic systems.

The effects of isothermal positrons and nonthermal electrons on the ion-acoustic double layers in warm multicomponent plasma having positive and negative ions are studied using pseudo potential technique.. The expression of Sagdeev potential has been derived and the solution for ion-acoustic double layers has been obtained from the nonlinear equation. The profiles of double layers have been drawn taking different values of plasma parameters. It is observed that both compressive and rarefactive double layers would be excited in presence of positrons and nonthermal electrons in the plasma. The variation of amplitudes and widths of double layers have been discussed graphically for different positron density, positron temperature, nonthermal electrons, negative ion density including drift velocity of ions.

PACS Numbers: 52.35.-g . 52.35.Mw, 52.35 Sb.