Biomedical Engineering Reference
In-Depth Information
0.08
29.5°C
29.8°C
30°C
30.2°C
30.5°C
0.06
0.04
0.02
ε
0.00
-0.02
-0.04
-0.06
-0.08
0
500
1000
1500
2000
t
(day)
(a)
0.08
29.5°C
29.8°C
30°C
30.2°C
30.5°C
0.06
0.04
0.02
η
0.00
-0.02
-0.04
-0.06
-0.08
0
500
1000
1500
2000
t
(day)
(b)
FIGURE 4.3
Variation of ε and η with time
t
for several temperature changes. (a) ε versus
t;
( b) η versus
t.
• Figure 4.4 shows the variation of ε and η with time
t
for vari-
ous values of electric potential difference. It can be seen that the
effect of the electric potential is exactly opposite to that of tem-
perature. A decrease in the intensity of the electric field results
in a decrease of the inner and outer surface radii of the bone
by almost the same magnitude. Theoretically, the results suggest
that the remodeling process might be improved by exposing a
bone to an electric field. Clearly, further theoretical and experi-
mental studies are needed to investigate the implications of this
exposure for medical practice.
• Case 4:
P
= 1500 N and internal pressure is produced by inserting a
rigid pin whose radius
a
*
is greater than
a
