## 3 Experimental Setup, Materials, and Procedure
### Experimental Apparatus Setup for ERT (Electrical Resistance Tomography)  
A special ERT signal processing unit and data acquisition setup for evaluating low conductivity solutions was designed in cooperation with Rocsole Inc. In this module, the initial experimental studies utilizing the low conductivity liquid solutions of demineralized water, tap water, and industrial food grade saturated sucrose solution were performed. Blender v2.79 design software was used to design the phantoms with a 10 mm diameter. Ultimaker-3E 3-D printer was used to 3-D print manufacture these phantoms using the acrylonitrile butadiene styrene (ABS) material. A test demonstration was performed to visualize the density distribution for sucrose crystals within the industrial food grade saturated sucrose solution. Figure 4a shows the laboratory-based semi-batch reactor with ERT sensors mounted on it and Figure 4b displays the schematic for ERT data acquisition flow.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \begin{tabular}{c} **Solution** \\ **Index** \\ \end{tabular} & \begin{tabular}{c} **Effective Ethanol** \\ **to Water Ratio** \\ \end{tabular} & \begin{tabular}{c} **Different Concentrations of** \\ **Sucrose Solutions (\% w/w)** \\ \end{tabular} & \
\begin{tabular}{c} **Sucrose Weight** \\ **Percentage in 100 mL** \\ \end{tabular} &
\begin{tabular}{c} **Effective Sucrose/Ethanol** \\ **Ratio in 100 mL Solution** \\ \end{tabular} \\ \hline
1 & & 33 & 33 & - \\
2 & & 44 & 44 & - \\
3 & & 55 & 55 & - \\
4 & & 66.67 & 66.67 & - \\ \hline
5 & & 33 & 19.87 & 1 \\
6 & & 4 & 24.85 & 1.33 \\
7 & & 55 & 29.25 & 1.66 \\
8 & & 66.67 & 33.16 & 2 \\ \hline
9 & & 33 & 16.58 & 0.5 \\
10 & & 44 & 20.95 & 0.66 \\
11 & & 55 & 24.88 & 0.83 \\
12 & & 66.67 & 28.44 & 1 \\ \hline
13 & & 33 & 14.22 & 0.33 \\
14 & & 44 & 18.10 & 0.44 \\
15 & & 55 & 21.65 & 0.55 \\
16 & & 66.67 & 24.90 & 0.66 \\ \hline \hline \end{tabular}
\end{table}
Table 1: The sucrose to ethanol ratio at the various concentration of the sucrose.  
Figure 3: (**a**) Experimental setup for the impedance spectroscopy testing unit with reactor placed over magnetic stirrer and syringe pump; (**b**) impedance spectrometer.  
This reactor was made up of Plexiglas. The inner diameter of the reactor was 83 \(\pm\) 0.3 mm. Sixteen circular-shaped sensors were placed along the perimeter at 5 cm from the bottom of the reactor. This allowed imaging of the planar region within the reactor. The distance between the sensors was 5.19 mm. The diameter of the sensor-head screw was 12 mm. The total surface area in contact with the medium for each sensor was 113.04 mm\({}^{2}\). The signal processing unit containing the amplifier and the noise removal electronics was mounted directly on the sensor tail. Using the MCX type of insulating co-axial cable, lossless transmission was achieved. The data acquisition system from Rocsole Inc. was utilized to acquire the ERT data. The Roc-GUI software interface was used to communicate between the ERT machine and the computer. The Bayesian reconstruction method was used to reconstruct the images [51].  
The ERT was tested with all the three solutions in the V-C mode of operation. The voltage injected, and the current detected at each sensor were recorded. A phantom of 10 mm made up of ABS was placed at the centre of the beaker within an industrial food grade saturated sucrose solution, and an image was reconstructed. Various experiments using phantoms and sucrose solutions with relatively higher conductivity were done by [34]. The industrial food grade saturated sucrose solution was acquired from the Polish sugar company Polski Cukier. The cleaned, refined white sugar crystals (250 g) were also provided by the company. The beaker was filled with 500 mL of the industrial food grade saturated sucrose solution. The 250 g sugar crystals were added using a funnel towards the centre of the beaker at a rate of 8.3 g/s. Fast reconstructions based on the Bayesian method were applied using Roc-GUI to observe the density distribution of the crystals.