We demonstrate a new class of hollow-core Bragg fibers that are composed of concentric cylindrical silica rings separated by nanoscale support bridges. We theoretically predict and experimentally observe hollow-core confinement over an octave frequency range. The bandwidth of bandgap guiding in this new class of Bragg fibers exceeds that of other hollow-core fibers reported in the literature. W...

Highly stable organic solids, based on van der Waals interactions between cylindrical porphyrinwires, exhibit unique square iodine-channels (10 × 10 Å) and exceptionally hollow porphyrinwires. The functionalized iodine-cavities could be capable of conferring specific adsorption behavior for mercury and lead ions, whereas hollow porphyrinwires might serve as a model for the development of hybrid...

The study of the stress distribution on a hollow cylindrical fiber placed in a composite material is considered in this work and an analytical solution for this stress distribution has been constructed. Finally some parameters such as fiber’s thickness and fiber’s length are considered and their effects on the distribution of stress have been investigated. For finding the governing relations, c...

Residual stresses are created usually undesirably during manufacturing processes, including casting, welding, metal forming, etc. Residual stresses alone or in combination with other factors can cause the destruction and fracture of components or significant decline in their service life. Therefore, it is crucial to measure the residual stresses. Contour method is a destructive testing method c...

Oxygen plasma treatment is introduced herein as a novel post-growth fabrication technique to engineer the macroscopic morphology of hollow carbon nanotube (CNT) pillars. Current fabrication techniques for patterned vertically-aligned CNTs only allow for the production of extruded structures with constant cross-sectional area. Oxygen plasma treatment is utilized to rectify this limitation by int...

This thesis presents design of dielectric resonator loaded antenna for wireless applications. The design is a Different shape Dielectric Resonator Antenna (DRA) using different material for wireless applications. Here the DRA is excited by conformal patch connected to co-axial feeding which is an effective feed mechanism and more efficient in energy coupling than other types of feeding techniqu...

The optimal distribution of the reinforcing fibers for stiffening hollow cylindrical composites is explored using the linear elasticity theory. The spatial distribution of the vascular bundles in wild bamboo, a nature-designed functionally graded material, is the basis for the design. Our results suggest that wild bamboos maximize their flexural rigidity by optimally regulating the radial grada...

We demonstrate guiding of cold 85Rb atoms through a 100-micron-diameter hollow core dielectric waveguide using cylindrical hollow modes. We have transported atoms using blue-detuned light in the 1st order, azimuthally-polarized TE01 hollow mode, and the 2nd order hollow modes (HE31, EH11, and HE12), and compared these results with guidance in the red-detuned, fundamental HE11 mode. The blue-det...

Heterogeneous catalysis is vital for a number of chemical, refinery and pollution control processes. The use of catalyst pellets of hollow cylindrical shape provide several distinct advantages over other common shapes, and can therefore help to enhance conversion levels in reactors. A better utilization of the catalytic material is probably most notable of these features due to the absence of t...

A large number of chemical, bio-chemical and pollution-control processes use heterogeneous fixed-bed reactors. The use of finite hollow cylindrical catalyst pellets can enhance conversion levels in such reactors. The absence of the pellet core can significantly lower the diffusional resistance associated with the solid phase. This leads to a better utilization of the catalytic material, which i...