We have shown that a semiconducting single-wall carbon nanotube ~SWNT! can be covered uniformly by titanium atoms and form a complex but regular atomic structure. The circular cross section changes to a squarelike form, and the system becomes metallic with high state density at the Fermi level and with high quantum ballistic conductance. Metallicity is induced not only by the metal-metal coupli...

The brass tubes with foam cores of AlSi7SiC3, AlSi7SiC3Fe1 and AlSi7SiC3Fe3 were produced as the crush-boxes with circle and square cross-section. Then axial compressive behavior and energy absorption capability of the foam-filled tubes were investigated during the quasi-static progressive plastic buckling. The uniaxial compressive stress–strain curves of the foam-filled brass tubes exhibited t...

Developing an innovative protective structure with excellent energy absorption performance is a continuous research effort. The emerging additive manufacturing techniques allow fabricating structures complex geometrical shapes which have the potential to yield unprecedented properties. Accordingly, in this paper, crush and behaviour of new designs, namely Concave Tubes (CTs) featuring inwardly ...

Impact is one of very important subjects which always have been considered in mechanical science. Nature of impact is such that which makes its control a hard task. Therefore it is required to present the transfer of impact to other vulnerable part of a structure, when it is necessary, one of the best method of absorbing energy of impact, is by using Thin-walled tubes these tubes collapses unde...

This paper presents the results of a study on the axial compressive strength of columnsstrengthened with FRP wrap. The experimental part of the study included testing 6 reinforcedconcrete columns in two series. The first series comprised three similar circular reinforced concretecolumns strengthened with FRP wrap. The second series consisted of three similar square columns,two with sharp corner...

The performance of two evaporatively cooled heat exchangers is analysed, one has plain circular tubes while the other one has plain oval tubes. Both are investigated under similar operating conditions in relation to airflow rates and inlet hot water temperatures. The circular tube is 10 mm o.d., and the oval tube (axes ratio 3.085) is formed from an 18 mm o.d. circular tube whose perimeter is p...