Asian Research Journal of Mathematics

Activation Energy and Chemical Reaction Effects on MHD Radiative Powell–Eyring Nanofluid Flow with Viscous Dissipation and Newtonian Heating over a Radially Stretching Surface

Obinna, Nwokorie — 2026-04-13

Non-Newtonian nanofluid flow over stretching surfaces is crucial in many industrial applications, where nanoparticles, magnetic fields, and thermal effects significantly enhance heat transfer and fluid behavior. Advanced models, particularly the Powell–Eyring fluid framework, effectively capture complex rheological behavior, making them essential for accurately analyzing flow and heat transfer over radially stretching surfaces in realistic engineering processes. This study investigates the unsteady magnetohydrodynamic (MHD) radiative flow of a Powell–Eyring nanofluid over a radially stretching surface, incorporating viscous dissipation, Newtonian heating, and chemical reactions with activation energy. Using similarity transformations, the boundary-layer equations for momentum, energy, and concentration are reduced to a nonlinear system and solved numerically via MATLAB’s bvp4c. Thermal radiation is modeled using the Rosseland approximation, and reaction kinetics follow a temperature-dependent Arrhenius expression. Parametric analysis shows that the magnetic field and Eckert number suppress velocity while enhancing temperature. Velocity decreases with higher Darcy number and material parameter, but rises with the Powell–Eyring parameter. Temperature increases with Brownian motion, temperature difference, radiation, and Biot number, but decreases with Prandtl number. Concentration decreases with temperature difference, chemical reaction, Brownian motion, and Schmidt number, while it increases with concentration slip, activation energy, and thermophoresis. Effects on skin friction, Nusselt, and Sherwood numbers are quantified, highlighting the influence of key dimensionless parameters on momentum, heat, and mass transfer. These results guide the optimization of reactive nanofluid systems in energy-intensive and chemical processes.

Perimetric Expansive Maps in Perturbed Metric Spaces

Ranjana Maravi — 2026-04-13

This paper develops a fixed point framework for mappings that expand triangular perimeters within the setting of perturbed metric spaces. By decomposing the distance structure into an exact metric and an adjustable perturbation, we show that surjectivity transforms forward perimetric expansion into backward contractive behavior, forcing geometric convergence of inverse orbits. This mechanism yields a powerful expansive analogue of classical triangular contraction principles and ensures the existence and uniqueness of fixed points under mild regularity and the absence of 2–cycles. Detailed examples reveal both borderline nonexpansive behavior and genuinely strict expansive regimes arising from hierarchical folding dynamics. Three applications demonstrate the breadth of the theory: (i)a nonlinear integral operator whose structural expansiveness ensures the existence of a unique equilibrium solution to a Volterra-type equation. (ii) a hierarchical deduplication model in which strict perimetric expansion enforces a unique canonical representative under repeated merging: and (iii) a cryptographic state–evolution scheme whose perimetric geometry captures collision resistance and guarantees a unique master seed. These results highlight the versatility of perimetric expansion in nonlinear analysis, structured data aggregation, secure computation, and integral-equation models.

Some New Lower Bounds for the Spread of a Nonnegative Matrix with a Zero Diagonal Element

Ram Asrey Rajput — 2026-04-20