Environmental Engineering Reference
In-Depth Information
Barrer
Unit of permeance of a material. The defi nition of 1 Barrer:
−
10
3
10 (cm gas) (STP) (cm thickness)
1Barrer =
(cm membrane area) sec (cm Hg pressure)
2
Here “cm
3
gas (STP)” represents the quantity of gas that would take up
one cubic centimeter at standard temperature and pressure (STP) as
calculated via the ideal gas law, i.e., the molar volume. The “cm thick-
ness” represents the thickness of the material whose permeability is
being measured, and “cm
2
membrane area” is the surface area of that
material. The conversion to SI units is 1 Barrer = 3.348
10
-19
kmol m/
×
(m
2
s Pa).
Beer's law
Law describing how the intensity (
I
) of light decreases if it passes through
a medium (gas):
I
−
rsi
=e
,
I
0
where
the absorption coeffi cient of the sub-
stance, and
l
the distance the light travels through the material (i.e., the
path length).
ρ
is the density of the gas,
σ
Bicarbonate
−
(HCO
)
CO
2
dissolved in water gives bicarbonate
:
3
−
+
CO (aq)
+
H O
HCO
+ H
2
2
3
See also
carbonate.
Biological pump
In ocean surface layers, organisms use sunlight to convert CO
2
into bio-
mass. If these surface organisms die and sink to the deep part of the
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