107Engineering Issues
critical for high-speed centrifuges. Induced vibrations caused by resonant frequen-
cies
o
f
t
he
a
pparatus
ca
n
a
lso
b
e
a
p
roblem,
a
nd
t
he
h
igh
r
otational
s
peed
o
f
t
he
c
entrifuge
r
esults
i
n
s
evere
me
chanical
s
tresses
o
n
t
he
o
uter
w
all
o
f
t
he
r
otor.
F
or
i
nstance,
i
f
t
he
1
0-cm
d
iameter
c
entrifuge
d
escribed
e
arlier
w
ere
c
onstructed
o
f
A
l,
t
he
t
ensile
s
tress
at
1
,000
r
ps
w
ould
b
e
1
1,000kg/cm
2
, or twice the tensile strength
o
f
t
he
m
aterial.
T
he
c
entrifuge
w
ould
u
ndergo
a
cat
astrophic
f
ailure
l
ong
b
efore
a
chieving
i
ts
o
perating
s
peed.
M
odern
c
entrifuge
r
otors
a
re
c
onstructed
o
f
h
igh-
strength
m
aterials,
s
uch
a
s
m
araging
s
teel
o
r
s
trong,
l
ightweight
c
omposite
m
aterials
l
ike carbon bers in a resin matrix.
Now
that the technical ...