The fluting instability has been suggested as the driver of subsurface structure sunspot flux tubes. We conducted a series numerical experiments where we used tubes with different initial curvatures to study effect on spots. MURaM code, which previously simulate complete sunspots, first compute four sunspots in slab geometry and then two circular spots opposite polarities. find that curvature t...

The hybrid structures composed of gold nanoparticles and carbon nanotubes were prepared using porous alumina membranes as templates. Carbon nanotubes were synthesized inside the pores of these templates by the non-catalytic decomposition of acetylene. The inner cavity of the supported tubes was used as nanoreactors to grow gold particles by impregnation with a gold salt, followed by a calcinati...

We study a new hybrid RANS/Variational Multiscale LES (VMS-LES) model for bluff body flows. The simulations have been carried out using a parallelized solver, based on a mixed element/volume formulation on unstructured grids. First, the behavior of a VMS-LES model with different subgrid scale models is investigated for the flow past a circular cylinder at Reynolds number Re =3900. Second, a new...

Offshore structures are exposed to risks of vessel collisions and impacts from dropped objects. Tubular members extensively used in offshore construction, thus, there is scope investigate their crashworthiness behaviour. Aluminium, glass fibre reinforced polymer (GFRP) hybrid aluminium/GFRP circular tube specimens were fabricated then tested under quasi-static dynamic axial loading conditions. ...

A modified hybrid waveguide with a wide-range coupling and long propagation has been proposed and the coupled mode theory has been applied to study the hybrid waveguide systematically. Two structures are comparatively discussed, namely, a dielectric wire and a circular capillary tube, which are buried in a polymer matrix and separated from the silver substrate by a gap. The simulated results in...

Thin-walled tube bending is still to be considered a new and advanced technique. The process has been adopted into several industries such as aero and automotive. This process may produce a wrinkling, bulking and tearing phenomenon if the process parameters are inappropriate, especially for tubes with large diameter and thin wall thickness. Push bending process is one of the methods used for be...

The favorable energy-absorption properties of metal foams have been frequently proposed for damping or anti-crash applications. The aim of this paper is to investigate the endurance of these properties for composite structures, made by a metal or a hybrid metal-polymeric foam used as the core filling of a tubular metal case. The results of experimental tests are shown, run with two types of str...

We investigate energetics and structure of circular and polygonal single wall carbon nanotubes (SWNTs) using large scale molecular simulations on NAS SP2, motivated by their unusual electronic and magnetic properties. The circular tori are formed by bending tube (n, n) whereas the polygonal tori are constructed by turning the joint of two tubes of (n, n), (n+1, n-1) and (n+2, n-2) with topologi...