Endotracheal tubes (ETTs) constitute a resistive extra load for intubated patients. The ETT pressure drop (DeltaP(ETT)) is usually described by empirical equations that are specific to one ETT only. Our laboratory previously showed that, in adult ETTs, DeltaP(ETT) is given by the Blasius formula (F. Lofaso, B. Louis, L. Brochard, A. Harf, and D. Isabey. Am. Rev. Respir. Dis. 146: 974-979, 1992)...

In this paper, the problem of large pure bending deformations of membrane is considered. The membrane is a sector of torus with a closed cross-section. This membrane is called a curved tube for short. We consider the homogenous, incompressible, isotropic and hyperelastic material. The external load is a constant pressure and bending couples acting at the edges. The equilibrium equations reduce ...

A boundary element model for the computation of sequence-dependent hydrodynamic properties of short DNA molecules is introduced. The hydrated surface is modeled as a curved tube of uniform radius with ends capped by hemispheres, and the axis of the tube is a general space curve whose length and curvature are determined locally by the sequence using a rigid basepair model of double-helical DNA w...

In order to decrease the fluid dynamic forces of the U-bent tube with a circular section and avoid the occurrence of fluid-structure interaction problems, three-dimensional simulations of fluid flows around the tubes are carried out. In the case that the axis of the curved tube with the circular section is prevented from being normal to the direction of the flows approaching the tube, the forma...

Effects of some important parameters like impactor effects, plug geometry and initiation points on bonding aluminum tubes to aluminum plugs were studied. The impact velocity and dynamic angle between tube and plug should be precisely managed to achieve an optimum bonding condition. A new explosive bonding technique with the use of two material impactors was proposed. Results are especially suit...

turbulent mixed convection of a nanofluid (water/al2o3, φ=.02) has been studied numerically. two-phase mixture model has been used to investigate the effects of nanoparticles mean diameter on the flow parameters. nanoparticles distribution at the tube cross section shows that the particles are uniformly dispersed. the non-uniformity of the particles distribution occurs in the case of large nano...

Vertical compact torus injection into the STOR-M tokamak has been conducted with the University of Saskatchewan Compact Torus Injector (USCTI). The injector stayed at the horizontal position and the CT was bent by 90 using a curved conducting drift tube. The curved drift tube did not have significant effects on the CT velocity. Furthermore, the curved drift tube did not change the magnetic fiel...

A new antidynamo theorem for non-stretched twisted magnetic flux tube dynamo is obtained. Though Riemannian curvature cannot be neglected since one considers curved magnetic flux tube axis, the stretch can be neglect since one only considers the limit of thin magnetic flux tubes. The theorem states that marginal or slow dynamos along curved (folded), torsioned (twisted) and non-stretched flux t...