We report the results of an analysis of the redshift power spectrum P (k, μ) in three typical Cold Dark Matter (CDM) cosmological models, where μ is the cosine of the angle between the wave vector and the line–of–sight. Two distinct biased tracers derived from the primordial density peaks of Bardeen et al. and the cluster–underweight model of Jing, Mo, & Börner are considered in addition to the...

In this work, nonlocal elasticity theory is applied to analyze nonlinear free vibrations of slightly curved multi-walled carbon nanotubes resting on nonlinear Winkler and Pasternak foundations in a thermal and magnetic environment. With the aid of Galerkin decomposition method, the systems of nonlinear partial differential equations are transformed into systems of nonlinear ordinary differentia...

The Eulerian cosmological fluid equations are used to study the nonlinear mode coupling of density fluctuations. We evaluate the second-order power spectrum including all four-point contributions. In the weakly nonlinear regime we find that the dominant nonlinear contribution for realistic cosmological spectra is made by the coupling of long-wave modes and is well estimated by second order pert...

The nonlinear mean-field dynamo due to a shear-current effect in a nonhelical homogeneous turbulence with a mean velocity shear is discussed. The transport of magnetic helicity as a dynamical nonlinearity is taken into account. The shear-current effect is associated with the W×J term in the mean electromotive force, where W is the mean vorticity due to the large-scale shear motions and J is the...

A K-surface is a surface whose Gauss curvature K is equal to a positive constant. In this paper, we will consider K-surfaces that are deened by a nonlinear boundary value problem. In this setting, existence follows from some recent results on nonlinear second-order elliptic partial diierential equations. The analytical techniques used to establish these results motivate eeective numerical metho...

We use a one-scale similarity analysis which gives specific relations between the velocity, amplitude and width of localized solutions of nonlinear differential equations , whose exact solutions are generally difficult to obtain. We also introduce kink-antikink compact solutions for the nonlinear-nonlinear dispersion K(2,2) equation , and we construct a basis of scaling functions similar with t...