OBJECTIVES To determine if the phenomenon of biofilm accumulation and associated microbial colonization occurs on the surface of endotracheal tubes in the region of the subglottis in neonates. METHODS Endotracheal tubes removed from 9 consecutive neonatal patients intubated for more than 12 hours were processed (range, 13 hours to 8 days). A sterile control tube was also processed. For each, ...

Abstract Judging from the development status of most super-high-rise building industries in China, “outer frame + core tube” is basically adopted. The appearance this tube structure design concept puts forward higher requirements for construction safety main structure. Combined with practical engineering projects, we analyze risks and countermeasures outer column super high-rise steel structure...

The pressure drop of refrigerant R-134a flow boiling inside a horizontal tube has been investigated experimentally. The test set-up which was used in this investigation is a well instrumented vapor compression refrigeration system. These instruments are thermocouples, flow meter, pressure gauges and the pressure drop measuring apparatus. This system consisted of three electrically heated evapor...

Abstract An atmospheric plasma jet reactor (PJR) was designed using two outer disc-like copper plats placed around a quartz tube. The effects of the electrodes’ thicknesses and their placement on length created in helium its electrical characteristics were investigated. Measurements carried out for different applied voltages gas flow rates. (such as discharge current power consumption) obtained...

in this study, fluid flow and energy separation in a micro-scale ranque-hilschvortex tube are numerically investigated. the flow is assumed as 2d, steady,compressible ideal gas, and shear-stress-transport sst k-w is found to be a bestchoice for modeling of turbulence phenomena. the results are in a good agreementwith the experimental results reported in the literature. the results show that flu...

in river meandering, when flow passes through a bend, reduction of flow velocity and rising hydrostatic pressure cause super elevation phenomena at outer side and reduction of water surface at inner-side of the bend. a helical motion results, causing erosion of the outer side of the bend. installation of submerged vanes on the stream bed can reduce erosion of the outer bank significantly. in th...

  In this study, fluid flow and energy separation in a micro-scale Ranque-HilschVortex Tube are numerically investigated. The flow is assumed as 2D, steady,compressible ideal gas, and shear-stress-transport SST k-W is found to be a bestchoice for modeling of turbulence phenomena. The results are in a good agreementwith the experimental results reported in the literature. The results show that f...

Tubular structural systems are one of the most common types of systems in high-rise structures. In the early days of this system, there were imperfections in its design which were overcome over time. The most important modification to rectify these defects is the use of a series of internal frames in addition to the peripheral frames and new systems in the center of the plan to eliminate design...

in this paper, turbulent mixed convective heat transfer of water and al2o3 nanofluid has been numerically studied in a horizontal tube under non-uniform heat flux on the upper wall and insulation in the lower wall using mixture model. for the discretization of governing equations, the second-order upstream difference scheme and finite volume method were used. the coupling of pressure and veloci...

in this paper, the problem of turbulent forced convection flow of water- alumina nanofluid in a uniformly heated pipe has been thoroughly investigated. in numerical study, single and two-phase models have been used. in single-phase modeling of nanofluid, thermal and flow properties of nanofluid have been considered to be dependent on temperature and volume fraction. effects of volume fraction a...