The small degree of circular polarisation observed in some synchrotron sources has a frequency dependence that is not consistent with simple predictions based on the intrinsic circular polarisation of synchrotron emission. The suggestion is explored that the circular polarisation arises as a propagation effect within the source. The physical basis of this alternative mechanism is the fact that ...

In this paper, an incident angle- and polarization-insensitive metamaterial absorber is proposed for X-band applications. A unit cell of the proposed absorber has a square patch at the centre and four circular sectors are rotated around the square patch. The vertically and horizontally symmetric structure of the unit cell enables polarization-insensitivity. The circular sector of the unit cell ...

Calculation of fin efficiency is necessary for the design heat exchangers. This can be calculated individual finned tubes or continuous fins. Continuous fins are mostly used in plate-fin and tube exchangers (PFTHEs). In most cases, basic elements those PFTHEs circular, oval flattened pipes, which contain circular polygonal fins, as observed PFTHEs, divided into virtual Those have a rectangular ...

This paper presents the design of a wideband circularly polarized antenna using a multiple-circular-sector dielectric resonator (DR). The DR is composed of twelve circular-sector DRs with identical central angles of 30 ∘ but with different radii. A genetic algorithm is utilized to optimize the radii of the twelve circular-sector DRs to realize wideband circular polarization. The proposed antenn...

-In this paper, we present recent efforts conducted to investigate the dynamic behavior of a sensor diaphragm under initial tension. A comprehensive mechanics model based on a plate with in-plane tension is presented and analyzed to examine the transition from plate behavior to membrane behavior. It is shown that for certain tension parameter values, it is appropriate to model the diaphragm as ...

This paper presents novel micromachined two-dimensional array piezoelectrically actuated flextensional transducers that can be used to generate sound in air or water. Micromachining techniques to fabricate these devices are also presented. Individual unimorph array elements consist of a thin piezoelectric annular disk and a thin, fully clamped, circular plate. We manufacture the transducer in t...

A description of self-stress produced by hydrogen absorption into thin metallic circular-plates with clamped edges is presented. The plate deflects when the average hydrogen content exceeds a critical value, which depends mainly on the size of the plate, if no external load is applied; the plate distortion exhibits bistable characteristics, i.e. the deflection direction may be either upward or ...