Figure 3 - Temperature rise over time determined experimentally
(blue line) and estimated with the finite element simulation (orange
line). a) 1.5 mL microcentrifuge tube with 1.5 mL sample at 50%
amplitude using a 3mm tip (corresponding to ~5.5 Watt)
and 10 second on and 10 second off pulse, initial temperature 1.6C.
b) 1.5 mL microcentrifuge tube with 1.5 mL sample at 50% amplitude
using a 3mm tip (corresponding to ~5.5 Watt) and 20
second on and 20 second off pulse, initial temperature 3.4C. c) 1.5
mL microcentrifuge tube with 1.5 mL sample at 25% amplitude using a 3mm
tip (corresponding to ~2 Watt) and 10 second on and 10
second off pulse, initial temperature 1.1C. d) 5 mL microcentrifuge
tube with 5 mL sample at 50% amplitude using a 6mm tip (corresponding
to ~12.5 Watt) and 20 second on and 20 second off pulse,
initial temperature at 14.4 C.
From the model and experimental data, we observe that the temperature
starts rising immediately as the sonication starts and within a
relatively short time (300-500 s) it reaches a steady state, a point
where the energy added by sonication is equal to the energy lost to the
ice-bath. It is also observed that the temperature follows a very
predictive parabolic pattern while rising and the model could capture
this effect. The model can then be used to estimate temperature rise for
different sonication conditions with different power input, vessel
geometry, sample volume and pulsing.