No. 1, 1998 - Tribology in Industry

yield stress of a gel rvas determined when the gel hegan
to flow.
The parameters k and n can be calculated using the
relations (5), (6) and (7) and the experimental results
presented in table 1. by the following method:
a) Shear rafes, for various values of rr (table 2) are calculated
using relation (5) and (7) and the erperimental
results {tabie 1);
b) The shear rates thus determined are used, together
with relation (6) and the results of table 1, to calculate
the values of k tactor and it's average site for various
values of rr (table 3);
Table 2
,iib"i ,-';^ i,fi'l "
3l_
0.86 I 0.87
L qo g l, ?o!,_! ?9,7 | qq-,6 ] 2o:g_L?g es
6.s-i *iijo*-l
_t-
i"" i *u I zs;s-l-zss
43.4 | +e.z j as I 42.7s \ 42.s I az.zs I +z I at.t
6."is i- 6.;-l uo* T *f -i;g-oi[ igif sg i--t *
- -f--- ---- - -j-
1---
86 i as.o I as,z 1 e+.e I sa.+ I uo j as.o
Gi;l 1277s]1 u;7,,ro tzt.z irzo.os oi- i , rzo.t rol ilirr I rzs.s l j ris--T res tzqt
,r"-J 'o{ i'*l;i.1
-rlg--@-r:q
153 152.4 15i.75
l- *' l19o
I r50.4
i-[.ealr1qlJ-r11r
11a9.75 i 149.1 I 148
'102.9 I 102.4 I 101.9 I 101.4 i 101 1100.55 I 100.1 I 99.6
I 151.1
-
^^;;- i ^^^- l-^^. - -- .. , -:^ ^^- I *
?337P_ 2326 , ?31 I 23oe 22ee 22e -_228_ l 4!
415.6 | 414.1
Table 3
t-t,
m'10-3
1.890
[o,
1 -rolR Tw
n 0.81 0.82
n oe
0.84 0.85 0.86 0.87 O.BB
m.10-3
Nm-2
'1.326 0.2984127 4275 108.332105.495102.745 100.08 97.693 95.182 92946 90.582
1 B9o I 1.28 ) Os42s2B1 4.562 98.150 95.239 92.425 89.705 87.199 84.775 oz.J to 79.938
1.890; 1134 04 5000
I at