specifically chosen so as to enable mixing for different compositions.
The sample size also differed for each type of powder mix;
for the P/S mix sample size was 2 g whereas for O/S mix the sample
size was 0.2 g because of the much lower mass of O/S in the mixer
and to facilitate ease of sampling. Since the sample size between
the two binary mixes P/S and O/S was different from each other
and sample size can influence the CoV values, trials were conducted
to investigate the effect of sample size for P/S and O/S.
The CoV for 50% P/S with 2 g sample size and 50% O/S with 0.2 g
sample size was 0.06 and 0.25 respectively at the end of mixing
and on decreasing the sample size of P/S mix to 0.2 g which is
the same as that of O/S sample size the CoV increased to 0.11
but this was still better than the CoV attained for O/S mix at the
end of mixing.
Fr ¼
v
ffigffiffi p
Lc ð1Þ
where
v, tip speed (m/s) = 0.47 m/s.
Lc, paddle length (m) = 0.053 m.