We construct a general effective dynamics for diffeomorphisms of spacetime, in fixed external metric. Though related to familiar models scalar fields as coordinates, our have subtly different properties, both at kinematical and dynamical level. The energy-momentum tensor consists two independently conserved parts. background solution is the identity diffeomorphism this gives rise an cosmologica...

linear dynamic response of simply supported nanobeams subjected to a variable axial force is assessed by galerkin numerical approach. constitutive behavior is described by three functional forms of elastic energy densities enclosing nonlocal and strain gradient effects and their combination. linear stationary dynamics of nanobeams is modulated by an axial force which controls the global stiffne...

‎In the following text for arbitrary $X$ with at least two elements‎, ‎nonempty countable set $Gamma$‎ ‎we make a comparative study on the collection of generalized shift dynamical systems like $(X^Gamma,sigma_varphi)$ where $varphi:GammatoGamma$ is an arbitrary self-map‎. ‎We pay attention to sub-systems and combinations of generalized shifts with counterexamples regarding Devaney‎, ‎exact Dev...

In this paper, global uniform exponential stability of perturbed dynamical systems is studied by using Lyapunov techniques. The system presents a perturbation term which is bounded by an integrable function with the assumption that the nominal system is globally uniformly exponentially stable. Some examples in dimensional two are given to illustrate the applicability of the main results.

In this paper, first the space of hyperbolic tangent functions is introduced and then the universal approximator property of this space is proved. In fact, by using this space, any nonlinear continuous function can be uniformly approximated with any degree of accuracy. Also, as an application, this space of functions is utilized to design feedback control for a nonlinear dynamical system.

stability and safety analysis of dams is a subject which has been studied in recent years by several researchers. researchers have used various methods and models for studying the stability of the dam. several methods are proposed for the analysis of earth dams under earthquakes. some of these methods are viscoelastic methods and semi static methods. each of these methods can be used as an appr...