The resonant transmission of a small annular aperture, with a diameter much smaller than the radiation wavelength, in a thin metal plate is studied at microwave frequencies. It transpires that such an annular aperture supports several resonant guided modes, including those that are not quantized in the azimuthal direction. Such modes have resonant frequencies that are largely independent of the...

the current study presents a new analytical method for buckling analysis of rectangular and annular beams made up of functionally graded materials with constant thickness and poisson’s ratio. the boundary conditions of the beam are assumed to be simply supported and clamped. the stability equations were obtained by using conservation of energy. the critical buckling load and first mode shape we...

plates and shells are the significant structural components for many engineering and industrial applications. in this study, free vibration analysis of annular plates is investigated. for this, two different numerical methods such as differential quadrature and discrete singular convolution methods have been performed for numerical simulations. frequency values have been obtained via these two ...

Background—Proponents of flexible annuloplasty rings have hypothesized that such devices maintain annular dynamics. This hypothesis is based on the supposition that annular motion is relatively normal in patients undergoing mitral valve repair. We hypothesized that mitral annular dynamics are impaired in ischemic mitral regurgitation and myxomatous mitral regurgitation. Methods and Results—A Ph...

BACKGROUND Defects in protein folding may lead to severe degenerative diseases characterized by the appearance of amyloid fibril deposits. Cytotoxicity in amyloidoses has been linked to poration of the cell membrane that may involve interactions with amyloid intermediates of annular shape. Although annular oligomers have been detected in many amyloidogenic systems, their universality, function ...

the subject of geometry and proportions has been regarded as an issue which has a close relationship with architecture. since the entire universe, living beings and the human geometry can be seen clearly, that’s why our unconscious essence has accustomed to these proportions whereby reflection of this mentality can be seen in the architect’s hands and thought in the architecture. it can witness...

In the present article, buckling analysis of functionally graded annular thin and moderately thick plates under mechanical and thermal loads is investigated. The equilibrium and stability equations of the plate are obtained based on both classical and first order shear deformation plate theories. By using an analytical method, the coupled stability equations are converted to independent equatio...

A theoretical investigation has been made of core-annular flow: the flow of a high-viscosity liquid core surrounded by a low-viscosity liquid annular layer through a horizontal pipe. Special attention is paid to the question of how the buoyancy force on the core, caused by a density difference between the core and the annular layer, is counterbalanced. From earlier studies it is known that at t...

Electromagnetic pulse (EMP) coupling into the annular apertures can disturb or damage much electronic equipment. To enhance electronic system’s capability of anti-electromagnetic interference, the finite difference time domain method (FDTD) was employed to study the characteristics of electromagnetic pulse coupling into the cavity enclosures with annular apertures. The coupling characteristics ...