s
t
l
e
e
t
l
i
t
m
l
a
t
i
p
v
c
n
i
a
e
i
n
t
s
u
q
b. Require little capital investments
e
e
r
h
c
u
t
s
s
o
t
g
d
g
e
s
i
g
i
n
n
h
i
s
e
v
e
m
t
w
o
c. Low investments but high designing costs
n
i
n
b
t
s
a
i
t
s
d. Long time to be installed
n
o
t
g
n
i
b
o
l
l
e
d
e
m
t
e
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