In this paper, a new method for radar cross section reduction of a monopole antenna is proposed. In this method, a plasma helix like fluorescent bulbs is placed around the antenna element. The selected plasma parameter for this medium acts as an absorber without disturbing the antenna performance. The simulations show that radar cross section of simulated antenna is reduced in a wide frequency ...

This paper deals with the effect of the intrinsic material length-scale parameter on the stability and natural frequency of a rectangular micro-plate for two different cases; fully clamped and fully simply supported. A variational formulation based on Hamilton’s principle and the modified couple stress theory is used to obtain the nonlinear governing equation of a micro-plate incorporating the ...

An accurate solution procedure based on the three-dimensional elasticity theory for the free vibration analysis of Functionally Graded Sandwich (FGS) plates is presented. Since no assumptions on stresses and displacements have been employed, it can be applied to the free vibration analysis of plates with arbitrary thickness. The two-constituent FGS plate consists of ceramic and metal graded thr...

The damping vibration characteristics of magneto-electro-viscoelastic (MEV) nanobeam resting on viscoelastic foundation based on nonlocal strain gradient elasticity theory (NSGT) is studied in this article. For this purpose, by considering the effects of Winkler-Pasternak, the viscoelastic medium consists of linear and viscous layers. with respect to the displacement field in accordance with th...

in this paper a new method is introduced and investigated for removing the destabilizing effects of time-delay parameter in control loops. the concept of the method is taken from the knowledge concerning the dynamic behaviour of irrational transfer functions (ir-tf), which is discussed and investigated elswhere in frequency response domain and is explained briefly here. ir-tfs, which are well c...

In the present work, the Rayleigh-Taylor instability of two rotating superposed magnetized fluids within the presence of a vertical or a horizontal magnetic flux has been investigated. The nonlinear theory is applied, by solving the equation of motion and uses the acceptable nonlinear boundary conditions. However, the nonlinear characteristic equation within the elevation parameter is obtained....

in this paper, distributed parameter process systems behavior is studied in frequency domain. based on the dominant gain concept that is developed for such studies, a method is presented to control distributed parameter process systems. by using dominant gain concept, the location of open loop zeros, resulted from the time delay parameter in the process model, were changed from the right half p...

the purpose of the present study is to compare the changes in b-value parameter using frequency-magnitude distribution for the data before and after the silakhor earthquake by gutenberg-richter relation. the variations of b-values are investigated using broadband iranian national seismic network center (bin). besides, spatial and time variations of the parameters were analyzed. the spatial vari...

film coating solutions containing different grades of hpmc (e5, e15 and e50) with and without polyethylene glycol (with various molecular weights) were examined by an oscillatory method, using haake cv 100 rheometer. fundamental rheological parameters (?, g? and g² ) were measured over the frequency range from 0.04 to 2 hz. the variation with frequency of the loss tangent (a ratio of viscous to...