Biomedical Engineering Reference
In-Depth Information
TABLE 9.2
SC
Enthalpic Phase Transition Data
Phase Change
Description
T
1
(
◦
C)
T
2
(
◦
C)
∆
H
(J/kg)
E
Fluidization of
lamellar lipids
65
75
5,300
F
Fluidization of
protein
associated lipids
75
90
4,100
G
Denaturation of
proteins
90
110
5,100
Source: Taken from data provided in Cornwell et al. 1996.
and is defined as
ϕ
=
(
H
−
c
SC
T
)
∆
H
E
(9.33)
where
H
is total enthalpy and is defined:
H
=
T
E
2
T
E
1
c
SC,AP P
dT
(9.34)
where ∆
H
E
is the latent heat associated with phase transition E, and
T
E
1
and
T
E
2
are the temperatures over which transition E takes place. The values
have been taken from experimental studies (see Table 9.2).
To simplify the description considerably, a rectangular shaped specific heat
versus temperature curve is used to model phase transitions (Bart and Van-
derLaag 1990; Roy and Avanic 2001).
The apparent
SC
specific heat,
c
SC,AP P
, is defined as
c
SC,AP P
=
c
SC
+
c
SC,L
(9.35)
where
c
SC,L
is the latent specific heat, which is represented as
∆
H
PC
T
PC
2
−
c
SC,L
=
(9.36)
T
PC
1
where ∆
H
is the latent heat,
T
2
and
T
1
are the representative phase change
end and beginning temperatures, and the subscript
PC
refers to one of the
three phase transitions: E, F, or G. Table 9.2 lists the values used in compu-
tations for the three
SC
phase change transitions. It is noted that long-pulse
duration is linked to increased postpulse electrical resistance recovery times
(
>
5 minutes) (Dujardin et al. 2002; Pliquett et al. 2005). The electric and
mass transport barrier properties of
SC
regions experiencing lipid thermal
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