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In order to get a complete full run for an experiment, we decided to temporarily decrease the ramp time to two hours for our ramp state functions. This created a problem with the smaller diameter tubes because tubes with smaller diameters use lower flow rates in the ramp state function. Because these flow rates are so low, the residence time in both the tube settler and the turbidimeter becomes significant. (Can you show these calculations?)
Proposed Solution
When designing future experiments in process controller, it is important to consider these residence times when determining the ramp time. In order to determine the ramp state time that should be used (it should be minimized to reduce potential error with the apparatus), a successful experiment needs to be completed. We are currently working to collect data for a successful run. The ratio of the experiment time to the residence time in the tube settler and the effluent turbidimeter will be applied to the residence times for all plate settler spacings to determine the best ramp time to be used.