This paper investigates the propagation of an air finger into a fluid-filled, axially uniform tube of elliptical or rectangular cross section with transverse length-scale a and aspect ratio α. Gravity is assumed to act parallel to the tube’s axis. The problem is studied numerically by a finite-element-based direct solution of the freesurface Stokes equations. In rectangular tubes, our results f...

here, we propose an optical filter and an optical power splitter based on two-dimensionalphotonic crystal all circular ring resonators. these structures are made of a square lattice ofsilicon rods with the refractive index n1=3.464 surrounded by air (with refractive indexn2=1). first, we have designed the filter and by using that, we designed a power splitter. thetransmission efficiency and qua...

The traditional 3 3 cell neighborhood used in a focal operation on a raster layer has a square shape that results in a dimensional neighborhood of which the orientation is eventually arbitrary to the physical features represented. This paper presents an experiment using a circular neighborhood to calculate slope gradient. Comparisons of the results from a circular neighborhood with the results ...

We examine the perturbations of the modes of an acoustic thermometer caused by circular ducts used either for gas flow or as acoustic waveguides coupled to remote transducers. We calculate the acoustic admittance of circular ducts using a model based on transmission line theory. The admittance is used to calculate the perturbations to the resonance frequencies and half-widths of the modes of sp...

Circular words are cyclically ordered finite sequences of letters. We give a computer-free proof of the following result by Currie: square-free circular words over the ternary alphabet exist for all lengths l except for 5, 7, 9, 10, 14, and 17. Our proof reveals an interesting connection between ternary square-free circular words and closed walks in the K3,3 graph. In addition, our proof implie...

Modified design of obtaining dual-circular polarization radiation of a single-feed square microstrip antenna are proposed and experimentally studied. The proposed single-feed dual circular polarized design is achieved by inserting four Tshaped slits at the patch edges of a square microstrip antenna. Details of the design considerations of the proposed antenna are described, and experimental res...

deformation length is one of the most important parameters in cold roll-forming process, which plays a fundamental role in determining the inter-distance between the stations and rate of deformation. deformation length was first introduced by bhattacharyya. he also obtained a closed-form relation for this length in roll-forming of symmetric channel section. in this paper, deformation length in ...

Experiments were conducted to study the performance of circular and square tank surface aerators on the oxygen transfer coefficient and to a limited extent on power requirements. All the tanks are geometrically similar except for their shapes. They consist of a rotor of diameter, D, fixed with six flat blades rotating with a speed, N, in pure waters of viscosity, υ, at room temperature. A simul...