An accurate semi-analytical approach for modeling electromagnetic scattering and guidance by photonic crystals formed by layered parallel-arrays or crossed-arrays of circular cylinders is presented , using the lattice sums technique, the T matrix algorithm, and the generalized reflection and transmission matrices for a layered system. The method is quite general and applies to various configura...

Acoustic band gap (ABG) materials constituted of steel hollow cylinders immersed in water can exhibit a tunable narrow pass band (NPB) located inside their gap. We theoretically investigate, using the finite difference time domain (FDTD) method, the properties of waveguides composed of a row of hollow cylinders in a two-dimensional (2D) phononic crystal made of filled steel cylinders. These wav...

the wild pistachio (pistacia atlantica mutika) exists in 2.4 million hectares of iranian forest. in spite of high nutritional and medical value of this fruit, its use and processing are still performed manually. the objectives of this research are to design, to construct and to evaluate the performance of a pistachio hulling machine. the pistachio of kerman province was chosen as the case of st...

The effect of interfacial resistance on the effective conductivity of a multi-phase composite material was studied. The composite under study is composed of a matrix surrounding different types of circular cylinders arranged in rectangular order. It was assumed that the interfacial resistance is concentrated on the surface of the cylinders. For any direction of calculating the effective conduct...

From the geometrical path statistics of rays in an anomalous-diffraction theory (ADT) [Opt. Lett. 28, 179 (2003)] closed-form expressions for the geometrical path distribution of rays and analytical formulas for the optical efficiencies of finite circular cylinders oriented in an arbitrary direction with respect to the incident light are derived. The characteristics of the shapes of the cylinde...

We present dimensionless effective transport coefficients (formation factors) for arrays of cylinders of various orientation distributions, namely, cylinders randomly positioned and oriented with their axes parallel to a line, parallel to a plane, or in the three-dimensional space with no preferred orientation. Both cases of conducting cylinders dispersed in a nonconducting matrix and nonconduc...

Recently, Guibas et al. 10 studied deformable necklaces – flexible chains of balls, called beads, in which only adjacent balls can intersect. In this paper, we investigate the problem of covering a necklace by cylinders. We consider several problems under different optimization criteria. We show that optimal cylindrical cover of a necklace with n beads in R by k cylinders can be computed in pol...

Laminar natural convection from an array of horizontal isothermal cylinders confined between two vertical walls, at low Rayleigh numbers, is investigated by theoretical and numerical methods. The height of the walls is kept constant, however, number of the cylinders and their spacing, the distance between the walls and Rayleigh number have been varied. The optimal spacing (confining walls) and ...