We investigate the hard nonresonant excitation of the forced Duffing equation with a positive damping parameter E. Using the symbolic manipulation system MACSYMA, a computer algebra system. we derive the two term perturbation expansion by the method of multiple time scales. The resulting approximate solution is valid for small values of the coefficient e As the damping parameter e increases, th...

here, a new method called aboodh transform homotopy perturbation method(athpm) is used to solve nonlinear partial dierential equations, we presenta reliable combination of homotopy perturbation method and aboodh transformto investigate some nonlinear partial dierential equations. the nonlinearterms can be handled by the use of homotopy perturbation method. the resultsshow the eciency of this...

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...

in this paper, the correlation between total ozone and upper air meteorological parameters such as heights of geopotential surfaces and temperatures for three stations of tehran, ankara and bet dagan located in the middle east, in cold period (jan, feb and march) of years of 2005, 2007 and 2008 has been investigated. data for upper air is taken from wyoming university and ozone data is from sat...

Abstract The gravity fields of celestial bodies that possess an atmosphere are periodically perturbed by the redistribution fluid mass associated with atmospheric dynamics. A component this perturbation is due to gravitational response body deformation its surface induced pressure loading. magnitude effect depends on relation between loading and in terms geopotential variations measured load Lo...

In this paper we calculate explicitly the secular classical precessions of the node Ω and the perigee ω of an Earth artificial satellite induced by the static, even zonal harmonics of the geopotential up to degree l = 20. Subsequently, their systematic errors induced by the mismodelling in the even zonal geopotential coefficients Jl are compared to the general relativistic secular gravitomagnet...

in this paper, the homotopy perturbation method (hpm) and elzaki transform is employed to obtain the approximate analytical solution of the sine gorden and the klein gorden equations. the nonlinear terms can be handled by the use of homotopy perturbation method. the proposed homotopy perturbation method is applied to reformulate the first and the second order initial value problems which leads ...

the earth’s gravity field dedicated missions provide homogeneous and uniformly accurate information on the long wavelengths of the earth’s gravity field. many different global geopotential models have introduced by earth and space research centers during the last years. the geopotential models derived from the grace satellite measurements are compared with the other models at different frequenc...