OBJECTIVE To investigate the value of high-flow nasal cannula oxygen therapy after extubation in patients with acute respiratory failure. METHODS A single-center, prospective, randomized, controlled pilot trial was conducted between January 2013 and December 2014. Sixty enrolled patients were randomized immediately after extubation into either a high-flow nasal cannula group (n=30) or an air ...

-In storm waterways and at dam outlets, high-velocity supercritical flows are characterized by substantial air bubble entrainment. The entrainment of fine air bubbles and the strong turbulent mixing contribute both to the air-water transfer of volatile gases (e.g. oxygen, nitrogen, VOC). The paper describes new experimental data obtained in a 25 m long channel with a 4 ° slope. The analysis of ...

A t the impact of a plunging liquid jet with a receiving pool, air bubbles may be entrained if the impact velocity exceeds a critical velocity. New experiments were performed in a two-dimensional plunging jet. The ̄ ow conditions near the inception of air entrainment were investigated. Two mechanisms of air entrainment were visualized at low jet velocities: by elongated air cavity and by foam bu...

The entrainment of air by advancing contact lines is studied by plunging a solid plate into a very viscous liquid. Above a threshold velocity, we observe the formation of an extended air film, typically 10 microns thick, which subsequently decays into air bubbles. Exploring a large range of viscous liquids, we find an unexpectedly weak dependence of entrainment speed on liquid viscosity, pointi...

Overview In free-surface flows the turbulence in the liquid may be sufficient to disturb the surface to the point of entraining air into the flow. This process is important, for example, in water treatment where air is needed to sustain microorganisms for water purification and in rivers and streams for sustaining a healthy fish population. Air entrainment is typically engineered into spillways...

This paper presents an analysis of water modeling of steel pouring to study (1) air entrainment and (2) filter effectiveness to remove reoxidation inclusions. In the first part, a review is presented of the physical processes and parameters important in air entrainment in free-surface flows. Then, the use of a water system to model air entrainment in steel pouring is analyzed. Attention is focu...

In open channel flows, local surface aeration processes occur mainly at weirs and drop structures and in hydraulic jumps. Air entrainment in the wakes of bluff bodies is observed only in high speed flows. In water pollution abatement, the natural gas exchange at the free surface is sometimes not sufficient to balance the oxygen consumption due to pollutants. In such cases, local aeration is nee...

Hydraulic researchers had been leading air–water flow studies until the mid-1950s. Since progresses have been dominated by multiphase flow experts despite the relevance of “white water” phenomena to hydraulic engineering. In this lecture the writer reviews the basic mechanisms of air entrainment: singular aeration and interfacial entrainment. The relevant instrumentation and data processing tec...