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The relationship between critical velocity and terminal velocity was also calculated, as the particle's size increases, terminal velocity becomes much larger than critical velocity, due to the fact that critical velocity is linear with respect to particle diameter but terminal velocity is proportional to the square of the diameter. However, if the slanting tube's diameter decreases, there will be a certain amount of small particles that roll up the tube, which would not happen in this case. (I did not see how your graph incorporated the critical velocity concept. Did I miss something?)
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Figure 1, the relationship between tube length, capture velocity, and the smallest particle diameter the tube can capture.
The length needed for the pipe in order to obtain a developed laminar flow 'Le', was also calculated and determined to be 10cm with the given (above) conditions. This is required to verify whether or not there is a parabolic profile at the end of the pipe. In conclusion, the length of the tube must be greater than Le. (How was this obtained?)
With the new apparatus, as shown in figure-3 below, a fourth trial will be carried out and evaluated. The modifications will be tested to see whether or not it will be successful in maintaining the pH at 12 and if so, for how long.
For this trial, distilled water will be used instead of
tap water (for what purpose?). In the pictures below, the ANC Control team can be seen carrying the distilled water tank on to the platform where the experiment is to be set up.
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