the current paper focuses on some analytical techniques to solve the non-linear duffing oscillator with large nonlinearity. four different methods have been applied for solution of the equation of motion; the variational iteration method, he’s parameter expanding method, parameterized perturbation method, and the homotopy perturbation method. the results reveal that approximation obtained by th...

The purpose of this study was to investigate univariate relationships between perceived dysphonia and variation in pitch perturbation, amplitude perturbation, and additive noise. A time-domain, pitch-synchronous synthesis technique was used to generate sustained vowels varying in each of the three acoustic dimensions. A panel of trained listeners provided direct magnitude estimates of roughness...

Semi-solid materials undergo strain localization and shear band formation as a result of granular nature of semi-solid deformation. In the present study, to analyze the shear localization, a unified viscoplastic constitutive model was developed for the homogeneous flow. Then, a linearized analysis of the stability performed by examining the necessary condition for the perturbation growth. For t...

In this paper, Elzaki Homotopy Perturbation Method is employed for solving linear and nonlinear differential equations with a variable coffecient. This method is a combination of Elzaki transform and Homotopy Perturbation Method. The aim of using Elzaki transform is to overcome the deficiencies that mainly caused by unsatised conditions in some semi-analytical methods such as Homotopy Perturbat...

Tunneling through time-dependent potentials is of relevance to a number of physical problems. Using a WKB analysis Azbel' has recently studied the effects of a nonharmonic time-dependent perturbation embedded in an opaque potential barrier. He suggests the existence of three different regimes for transmission in such systems: direct tunneling, activation assisted tunneling, and elevator resonan...

This paper is concerned with the direct and inverse acoustic or electromagnetic scattering problems by a locally perturbed, perfectly reflecting, infinite plane (which is called a locally rough surface in this paper). We propose a novel integral equation formulation for the direct scattering problem which is defined on a bounded curve (consisting of a bounded part of the infinite plane containi...

in this paper, first a new homotopy perturbation method for solving a fractional order nonlinear telegraph equation is introduced. by applying the proposed method, the nonlinear equation is translated to linear equations for per iteration of homotopy perturbation method. then, the obtained problems are solved with separation method. in the examples, it is illustrated that the exact solution is ...

Transient energy growth of disturbances to co-rotating vortex pairs is investigated in an analysis where vortex core expansion and vortex merging are included. The dynamics of pairs are compared to those of individual vortices in order to highlight the effect of vortex interaction. Three typical vortex pair cases are studied, with the pairs comprised respectively of individually asymptotically ...