Biomedical Engineering Reference
In-Depth Information
Polystyrene containers (Sterilin, UK)
Programmable power supply (ISO-TECH IPS-405, RS Components, UK)
Rectangular glass boxes (dimensions 275 mm
150 mm
60 mm)
Retort stands
Rothenberger Super Fire 2 gas torch (Rothenberger Werkzeuge GmbH,
Germany)
Sieves (Endecotts, UK)
Sieve shaker (Fritsch Spartan, Germany)
Stainless steel trowel spatula
Steel plate
Test connectors (4 mm banana plugs and alligator clips)
Three-pronged clamps
Weight balance (resolution of 0.1 g)
d
n
3
r
4
n
g
|
3
5.2.3 Calculations of the Precursor Amounts
As an example, consider a glass having the composition 0.5P
2
O
5
-0.4CaO-
0.09Na
2
O-0.01TiO
2
(all values in molar fraction). The amounts of precursors
used to manufacture this phosphate glasses can be calculated as follows.
5.2.3.1
Sodium Dihydrogen Orthophosphate (NaH
2
PO
4
)
2NaH
2
PO
4
-
Na
2
O
þ
P
2
O
5
þ
2H
2
O
Mol. wt. (g mol
1
)
240
62
142
36
.
Relative mol. wt. (g mol
1
)
0.26
0.59
0.15
Here, the amount of NaH
2
PO
4
to be added in order to obtain 9 mol%
Na
2
O:
¼
[(mol. fraction)
(mol. wt.)]/(relative mol. wt.)
¼
(0.09
62)/(0.26)
¼
21.46 g
5.2.3.2 Phosphorus Pentoxide (P
2
O
5
)
The amount of P
2
O
5
produced in the above reaction
¼
(amount of NaH
2
PO
4
produced)
(relative mol. wt. of P
2
O
5
)
¼
21.46
0.59
¼
12.66 g
The amount of P
2
O
5
required to produce 50 mol% P
2
O
5
¼
0.50
142
¼
71.00 g
Therefore, the actual amount of P
2
O
5
to be added is:
¼
71.00
12.66
¼
58.34 g
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