Initially, the

gas density leaving VB2 (MV2) is lower than the

gas density in the upper part of Vessel 2 (Figure 5) but later the

gas density becomes higher (mark B) than the gas in the top of Vessel 2 and the density becomes even higher than the density in the upper part of Vessel 1 (mark C).

Caption: Figure 17: The effect of

gas density on apparent permeability of shale (pore diameter = 50 nm).

Here [[rho].sub.b] is the burned

gas density in the schlieren flame sphere, [[rho].sub.u] is the unburned

gas density, and [r.sub.f] is the instantaneous schlieren flame radius in the horizontal direction.

Fabian and his colleagues showed that these ripples correspond to places in the cluster where the

gas density is slightly higher than the average.

where [rho] is the

gas density (kg/[m.sup.3]), u is the gas velocity vector (m/s), [C.sub.i] is the mass fraction of species i (--), [D.sub.i,m] is the molecular diffusivity of species i ([m.sup.2]/s), [[mu].sub.t] is the turbulent viscosity (kg/m x s), S[c.sub.t] is the turbulent Schmitt number (= 0.7 for gases), and [R.sub.i] is the net rate of production by chemical reaction (kg/[m.sup.3] x s).

The relationship between diffusion and

gas density is clearly observed in Graham's Diffusion Law, which states that diffusion velocity is inversely proportional to the square root of

gas density (Cremasco, 2002).

is the

gas density, dV is the volume element and DT/D represents the temperature substantial derivative depending on time.

If the span gas is regulated at a pressure greater than local atmospheric conditions, the

gas density will be greater, yielding a false calibration.

Various studies have been performed during the last 40 years investigating the relationships between

gas density and airflow in a selection of obstructive disorders.

On entering the surrounding cooler air of the atmosphere, the hot gas begins to cool as it rises, which progressively reduces the gas volume, with a proportional increase in the

gas density.