An analytical technique is proposed for estimation of the radiation pattern of inverted-F antenna (IFA) which is mounted on the side wall of a long cylinder. The method can be applied to describe the IFA radiation in a lot of practical cases. It is indicated that this radiation pattern is a combination of radiation patterns of a horizontal and a vertical small radiator, near the cylinder with a...

An analytical expression for the shape of the capillary menis, R formed around a vertical cylinder or spherical particle near a vertical wall is derived by using the method of matched asymptotic expansions. The forces of capillary interaction bctwccn the particle (cylinder) and the wall arc calculated. The resulting expressions are valid when the distance bctwecn the particle (cylinder) and the...

We consider the Rayleigh-Taylor instability problem of two initially stationary immiscible viscous fluids positioned with the denser above the less dense in a finite circular cylinder such that their starting fluid-fluid interface is the horizontal midplane of the cylinder. The ensuing linear instability problem has a 5D parameter space defined by the density ratio, the viscosity ratio, the cyl...

the gravity method is one of the first geophysical techniques used in oil and gas exploration. an algorithm is developed for a fast quantitative interpretation of gravity data generated by geometrically simple but also the estimated depths and other model parameters of a buried structure. following abdelrahman et al (1989). the general gravity anomaly expression produced by a sphere, an infinit...

in this work, the steady and laminar mixed convection of nanofluid in horizontal concentric annulus withrotating inner cylinder is investigated numerically. the inner and outer cylinders are kept at constanttemperature ti and to respectively, where ti>to. the annular space is filled with alumina-water nanofluid.the governing equations with the corresponded boundary conditions in the polar coord...

in this paper, a general solution for torsion of hollow cylinders made of functionally graded materials (fgm) was investigated. the problem was formulated in terms of prandtl’s stress and, in general, the shear stress and angle of twist were derived. variations in the material properties such as young’s modulus and poisson’s ratio might be arbitrary functions of the radial coordinate. various m...