air entrainment


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air entrainment

[¦er in′trān·mənt]
(engineering)
The inclusion of minute bubbles of air in cement or concrete through the addition of some material during grinding or mixing to reduce the surface tension of the water, giving improved properties for the end product.

air entrainment

The occlusion of air in the form of tiny bubbles (generally smaller than 1 mm) during the mixing of concrete or mortar; used to improve its workability.
References in periodicals archive ?
5, a demonstrates water surface deformation by falling jet and air entrainment start.
In physical hydraulic modelling, scale effects of air entrainment are substantial and corrections are needed to reasonably approximate prototype situations [19, 20].
For higher injection durations, the half-cone angles decrease again after t [approximately equal to] 1.4 ms due to the air entrainment at the outside of the spray sheet.
However, with the increase of air entrainment further away from the nozzle, fuel mass fraction at spray tip decreases, and so do spray-induced density gradients.
Gore, "Air entrainment flow field induced by a pool fire," Combustion and Flame, vol.
The original study initiated by ASHRAE, undertaken by Hadjisophocleous and Zhou (2007) at Carleton University, and the University of Maryland study by Kerber and Milke (2007) conclude that increased makeup air velocity increases air entrainment into the fire plume and creates greater volumes of smoke, resulting in a deeper smoke layer.
Here, the emphasis was laid on the air entrainment limit.
Many oxygen therapy devices employ the Venturi effect to accomplish air entrainment for the purpose of diluting 100% oxygen (used as the source gas) with room air.
But, it has some disadvantages such as scaling effects, time consuming, expensive, requirement of skilled labour and cannot readily capture behavious like cavitation and air entrainment effects, which occur in reality [3].
Simultaneous occurrence of free surface and mixed stratified flow conditions appears often in gravity-driven-flow pipelines, but most design criteria do not consider the causes of air entrainment (Pozos et al., 2010).
In the concrete industry, "air entrainment" refers to:
The new regulations address the risks from coal ash disposal as far as leaking into ground water, air entrainment, and the catastrophic failure of coal ash surface impoundments.