# Mitigating Electrochemical Effects in Resistive Frost-Detection Sensors
## 3 Results
Gas production and the formation of both blue and black materials at both electrodes nearly stopped, with only slight gas production still observable at the bottom. Gas production, as well as the formation of both blue and black materials, is still not observed. The blue material has almost completely precipitated to the bottom, severing the connection between the cathode and anode, leaving only water between them. Gas bubble formation resumes at this stage. \begin{table}
\begin{tabular}{p{142.3 pt} p{142.3 pt}} \hline \hline \(t=0:30\) h & At this time, gas bubbles are clearly observed forming near both electrodes, a blue substance is noticeably present on the left side of the anode, and the cathode has developed a polished, reflective surface. All three phenomena were already present at \(t=0\):05 h; however, at that earlier time, the polished surface was fully formed, while the blue substance and gas bubbles were nearly imperceptible, only becoming more noticeable around \(t=0\):20 h. \\ \hline \(t=1:00\) h & The blue layer on the anode grows significantly, and gas bubble production continues, but significantly more at the cathode, where hydrogen gas bubbles dislodge and flow to the surface at smaller sizes, contrary to the oxygen bubble that grows on the electrode surface. The lower part of the blue precipitate spreads to about half the distance between electrodes and begins to become dark. \\ \hline \(t=1:30\) h & The blue layer on the anode continues to expand toward the cathode and begins dislodging from the electrode, precipitating into the solution. Simultaneously, the cathode develops a progressively darker appearance as a black material starts to coat the entire electrode surface. \\ \hline \(t=2:30\) h & The upper portion of the blue material dislodges from the anode and connects to the top region of the cathode. The bottom section also detaches and bends toward the cathode, where it begins to become dark, particularly near the cathode. Meanwhile, the black substance continues to accumulate around the cathode surface, with a more significant buildup on the side facing the anode. \\ \hline \(t=3:30\) h & Gas production and the formation of both blue and black materials at both electrodes nearly stopped, with only slight gas production still observable at the bottom. \\ \hline \(t=4:30\) h & Gas production, as well as the formation of both blue and black materials, is still not observed. \\ \hline \(t=5:30\) h & The blue material has almost completely precipitated to the bottom, severing the connection between the cathode and anode, leaving only water between them. Gas bubble formation resumes at this stage. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Observations in electrodes during testing for the continuously powered sensor reading method. Figure 10: Sensor electrodes during testing for the continuously powered sensor reading method. It should again be noted, as seen in Figure 9, that, for the images in the top row of Figure 10 from \(t=0:00\) h to \(t=1:30\) h, the time interval between pictures is 0:30 h, whereas in the bottom row, from \(t=2:30\) h to \(t=5:30\) h, the interval is \(1:00\) h.  
The progression of dark material accumulation on the cathode was quantified based on the percentage of black pixels in the corresponding image region. These values are plotted in Figure 11 for both excitation methods. The results are coherent with the images, as the subjected to continuous excitation exhibited a sharp increase in black pixel percentage after \(t=1:00\) h, which consistently increased up to \(t=4:00\) h when the images confirm that the growth had stabilized. In contrast, the sensor excited using 50 ms pulses showed a much lower and more stable percentage of black pixels throughout the test duration. The accumulation of blue material on the anode was quantified based on the percentage of remaining non-black and non-red pixels in the cropped image region. Figure 12 presents the evolution of this value over time.