The interaction between Euler buckling and Brazier instability in an orthotropic cylindrical tube was investigated. A simple closed-form interaction curve was obtained by using the principle of minimum potential energy including the 3D extended Brazier’s 2D type cross-section ovalization and the potential energy of axial compression. The interaction curve consists of an Euler buckling load and ...

Dirichlet Laplacian on curved tubes of a constant cross section in two and three dimensions is investigated. It is shown that if the tube is non{straight and its curvature vanishes asymptotically, there is always a bound state below the bottom of the essential spectrum. An upper bound to the number of these bound states in thin tubes is derived. Furthermore, if the tube is only slightly bent, t...

We calculated the effects of structural distortions on the electronic structure of carbon nanotubes. The main effect of nanotube bending is an increased mixing of σ and π-states. This mixing leads to an enhanced density-of-states in the valence band near the Fermi energy. While in a straight tube the states accessible for electrical conduction are essentially pure C(2pπ)-states, they acquire si...

Intratracheal combustion of a fiberoptic bronchoscope and an endotracheal tube occurred during the treatment of severe tracheal stenosis with the neodymium-YAG laser. This recognized hazard of CO2 laser surgery has not been reported previously with the use of the Nd-YAG laser. Fire hazard is inevitable when a laser is used in the airway, but the risk can be diminished. Rapid removal of the burn...

The choice of the process parameters in the conventional tube bending forming is often based on experience and adjusted by repeated bending tests. The method of constantly testing to adjust has seriously affected the production efficiency and increased production costs. In this paper, neural network is used to establish the intelligent prediction model of the pipe forming process parameters. Th...