Volume 16, Issue 6 -

In this paper, we analyze the stability and Hopf bifurcation of a biological economic system with harvesting effort on prey. The model we consider is described by differential-algebraic equations because of economic revenue. We choose economic revenue as a positive bifurcation parameter here. Different from previous researchers’ models, this model with nonlinear harvesting rate is more general. Furthermore, the improved calculation process of parameterization is much simpler and it can handle more complex models which could not be dealt with by their algorithms because of enormous calculation. Finally, by MATLAB simulation, the validity and feasibility of the obtained results are illustrated.

In this paper a generalized fractional modified Korteweg–de Vries (FmKdV) equation with time-dependent variable coefficients, which is a generalized model in nonlinear lattice, plasma physics and ocean dynamics, is investigated. With the aid of a simplified bilinear method, fractional transforms and symbolic computation, the corresponding N -soliton solutions are given and illustrated. The characteristic line method and graphical analysis are applied to discuss the solitonic propagation and collision, including the bidirectional solitons and elastic interactions. Finally, the resonance phenomenon for the equation is examined.

In this paper, numerical simulations of two-dimensional reaction–diffusion (for single and multi-species) models are considered for pattern formation processes. The nature of our problems permits the use of two classical approaches. These semi-linear partial differential equations are split into a linear equation which contains the highly stiff part of the problem, and a nonlinear part that is expected to be varying slowly than the linear part. For the spatial discretization, we introduce higher-order symmetric finite difference scheme, and the resulting ordinary differential equations are then solved with the use of the family of implicit–explicit (IMEX) schemes. Stability properties of these schemes as well as the linear stability analysis of the problems are well presented. Numerical examples and results are also given to illustrate the accuracy and implementation of the methods.

The present work makes an analysis on the effects of second-order velocity slip and temperature jump boundary conditions for third-grade nanofluid over a coaxial cylinder. In the modeling of blood-based nanofluids containing metal or metal oxide nanoparticles, the viscosity is approximated to second-order Maclaurin’s series for the first time and the effective density is handled to a combination of temperature and nanoparticles volume fraction. The governing equations are transformed into a dimensionless system of nonlinear differential equations and solved by homotopy analysis method (HAM). The accuracy and efficiency of the HAM solutions are verified by ℏ$$\hbar $$-curves and residual error curves using package BVPh2.0. The physical interpretations are illustrated by graphs and tables. The results revealed that the Nusselt number increases with an increase of nanoparticle volume fraction. The second-order velocity slip has a significant weakened effect on the skin friction. In addition, the Brownian motion and thermophoresis movement are collaborating to increase the temperature profile.

This paper endeavors to formulate a stable and fast algorithm for the first time that is quite accurate and fast for numerical evaluation of the Hankel transform using wavelets which are usually difficult to solve analytically so it is required to obtain the approximate solution. So we have proposed an approach depending on separating the integrand rf(r)Jν(pr)$rf(r){J_\nu}(pr)$ into two components, the slowly varying components rf(r)$rf(r)$ and the rapidly oscillating component Jν(pr)${J_\nu}(pr)$. Then either rf(r)$rf(r)$ is expanded into wavelet series using wavelets orthonormal basis which are first derived and truncating the series at an optimal level or approximating rf(r)$rf(r)$ by a quadratic over the subinterval using the Filon quadrature philosophy. A good covenant between the obtained solution and some well-known results has been obtained. The solutions obtained by proposed wavelet method indicate that the approach is easy to implement and computationally very attractive. The novelty of our method is that we give error analysis for wavelet method for the first time in literature.