Microstrip antennas are conformable to planar and nonplanar surfaces, simple and inexpensive to fabricate using modern printed-circuit technology. Circular polarization of low-profile microstrip patch with high bandwidth is achieved in this research through the use of a three-cross-arms branch-line coupler with sequential rotated arrays, another low-profile antenna of hollow cylinder is also pr...

n a recent paper [l], Van Blade1 discussed in detail the behavior I of fields j . ' and surface charges near singularities of metallic struc$res, such as a hollow circular cylinder, a circulai cone, a thin prolate spheroid, and a uniformly charged segment. At times, the reasoning in [I] leads to conclusions not as definitive as one might wish because of the various approximations introduced, su...

From the past earthquake events, m at the exit while they are trying to go out of the bu the exit doors are unable to be opened. The door is it deviates from its the original position. The aim o develop and evaluate a new type safety door that ke in its original position or keeps its edge angles pe and post-earthquake. The proposed door is c components: outer frame joined to the wall, inner and...

The radiation characteristics of hemispherical DRA elements mounted on or embedded in a hollow circular cylindrical ground structure are investigated. The performance of the DRA array which operates at about 1.8 Ghz, is studied. Factors influencing the array performance, such as the number of elements and element spacing are explained. The perforated dielectric technique is used to design the a...

A new numerical technique is proposed for analyzing arbitrary shaped hollow waveguides. The method is based on mathematically modelling of physical response of a system to excitation over a range of frequencies. The response amplitudes are then used to determine the resonant frequencies. The results of the numerical experiments justifying the method are presented. The method is validated by cir...

A short review is presented of the cylinder problem as a vehicle for developments in the theory of linear viscoelastic stress analysis. This is followed by the solution of the problem of a compressible, hollow circular viscoelastic cylinder encased in and bonded to an elastic cylindrical shell. The analysis includes the effects of arbitrarily varying angular velocity and internal pressure, and ...

With the rapid expansion of urbanization, shafts are needed to provide access tunnelling projects or be utilized for permanent works. Their construction causes ground movements, affecting nearby foundations and buried infrastructure. This study presents an analytical equivalent volume loss approach predicting three-dimensional movements resulting from a circular shaft construction: namely, loss...

In recent decades, many dams have been built or are under construction. Due to the high demand for water and soil erosion, increasing the need for dam construction in different regions are quite tangible. In 1900 the number of large dams, did not exceed 50. But in the 1950s to 1986 the number of large dams (over 15 meters), more than 39,000 were counted. The 70s dams has been increasing develop...

Truss structures are widely used in construction of large-scale buildings. Design of steel structures is standardised in detail through set of European standards called EUROCODE. One of these standards, ENV 1993-1-8 deals with design of joints, but it does not cover the design of conical element for reduction of circular hollow section to the joint. Finite element method was used in this paper ...