Vector diffraction theory was applied to study the effect of two- and three-zone annular multi-phase plates (AMPs) on the three-dimensional point-spread-function (PSF) that results when linearly polarized light is focused using a high numerical aperture refractory lens. Conditions are identified for which a three-zone AMP generates a PSF that is axially superresolved by 19% with minimal change ...

A new genus (Cerchnotocriconenta) and three new species (C. psephinum, Hemicycliophora amchitkaensis, and Paratylenchns amundseni) are described from Adak and Amchitka Islands in the Aleutian chain. The new genus differs from all other criconematid genera in having irregular, convex sculpturing consisting of small, oval plates on the anterior and posterior regions of each annule, with the mid-a...

Optical vortex, possessing an annular intensity profile and an orbital angular momentum (characterized by an integer termed a topological charge) associated with a helical wavefront, has attracted great attention for diverse applications due to its unique properties. In particular for terahertz (THz) frequency range, several approaches for THz vortex generation, including molded phase plates co...

In this paper, the method of fundamental solutions (MFS) for solving the eigenfrequencies of multiply connected plates is proposed. The coefficients of influence matrices are easily determined when the fundamental solution is known. True and spurious eigensolutions appear at the same time. It is found that the spurious eigensolution using the MFS depends on the location of the inner boundary wh...

In this paper, numerical investigation of upward two phase flow of air-water has been studied. Different conditions of flow regimes including annular, wispy annular, slug, churn and bubbly are simulated based on Hewitt and Roberts map, and a good agreement between the experimental data of the map and the numerical simulation has been observed. Accordingly, a proper CFD model in CFD software of ...

Determination of prestress fields in structures is the utmost importance, since they have a significant impact on operational characteristics, and their level distribution must be strictly controlled. In this paper, we present modeling bending vibrations solid annular round inhomogeneous prestressed plates within framework Timoshenko hypotheses. New inverse problems identification are studied b...

The numerical simulation of beams and plates with embedded acoustic black holes (ABHs) is computationally demanding because the very thin thickness attained at ABH central area. Semi-analytical approaches relying on Rayleigh-Ritz method wavelet or Gaussian basis functions have thus revealed as an accurate fast alternative to determine vibration field in parametric studies. To date however, vast...

In this paper, a semi-analytical approach is proposed to solve natural frequencies and natural modes for circular plates with multiple circular holes by using the indirect formulation in conjunction with degenerate kernels and Fourier series. All the kernels in the indirect formulation are expanded into degenerate form. By uniformly collocating points on the boundary, a linear algebraic system ...

The functionally graded materials (FGM) have many advantages especially in thermal environments, and in the recent years they have been used in many engineering applications. A FGM plate is an inhomogeneous composite made of two constituents (usually ceramic and metal), with both the composition and the material properties varying smoothly through the thickness of the plate. The FGM plate vibra...

The main spectral property of a Sonic Crystal structure is a notable sound attenuation related to the Bragg band gaps. This effect is observed in air and makes Sonic Crystals effective noise barriers in a particular frequency range. This performance can be extended to a wider range of frequencies by introducing scatterers supporting multiple resonances of various types. In this paper the sonic ...