## 3 Results and Discussion  
### Moisture Content (MC) and Corrected Mass Loss (CML)  
The mean initial moisture content ranged from 12.51% (CS160) to 11.40% (OS210), resulting in a mean amplitude of only 1.11 percentage points (p.p.) (Figure 4). This indicates that the initial MC of the samples under the different treatments was homogeneous and had no impact on further processing. For all treatments, the final MC was lower than the initial MC, indicating the effect of the drying steps during thermal modification in both closed and open systems. The most remarkable result in Figure 4 is that different processes caused different effects on the final MC. CS160 had the highest final MC, reaching 9.09%, which represents a drying of only 3.42 p.p. compared to the initial MC. In contrast, the open-system treatments resulted in a final MC close to 0%. This discrepancy is mainly due to the types of heating and equipment used. In the CS160, the system was closed, which prevented the elimination of gases generated in the thermal modification process. In addition, heating was performed by injecting steam into the autoclave, which increased the availability of water in the  
Figure 3: Positioning scheme (red circles) for colorimetric readings; units in millimeters. \begin{table}
\begin{tabular}{c c} \hline
**Total Color Variation (\(\Delta\)E*)** & **Classification** \\ \hline
0.0–0.5 & Trace \\ \hline
0.6–1.5 & Slight \\ \hline
1.6–3.0 & Noticeable \\ \hline
3.1–6.0 & Appreciable \\ \hline
6.1–12 & Much \\ \hline \end{tabular}
\end{table} 
Table 3: Perceived difference after thermal modification (\(\Delta\)E*) [29]. system (increased relative humidity). On the other hand, in OS185 and OS210, the gases generated during the thermal modification were continuously eliminated. [PERSON] et al. [11] also reported this same pattern for thermally modified Eucalyptus nitens in closed and open systems. It is also noted that, for the open-system treatments, the final MCs were similar, regardless of the final temperature (185 \({}^{\circ}\)C and 210 \({}^{\circ}\)C). This indicates that the 25 \({}^{\circ}\)C temperature difference had no significant impact on the final MC, and the equipment worked similarly to a dry kiln. For [PERSON] et al. [30], the lower final MC is considered a positive effect for the open-system process because the wood can have a higher mechanical resistance, which can compensate, in part, for the reduction caused by the mass loss imparted by the process. However, the same effect will result in wood that is more difficult to machine process. The results of CML per treatment are shown in Figure 5. During thermal modification, cell wall constituents are degraded and can be accounted for as extractives during Soxhlet extraction. Furthermore, depending on the type of process, thermal modification can cause the volatilization of extractives and other molecules resulting from cell wall degradation. Thus, CML is a useful tool for neutralizing the effect of wood extractives on mass loss results. It is noted in Figure 5 that the different processes of thermal modification influenced the CML results. The CML was close to zero (0.33%) for OS185, indicating that this treatment slightly affected the wood constituents, even the most thermally labile ones. This suggests that the OS185 treatment was ineffective, basically resulting in a drying process of the wood. OS210 had a slightly higher CML (2.44%) than OS185, showing the effect of increasing temperature on mass loss for the same kind of process (open system). Open-system processes carried out at atmospheric pressure depend mainly on heat to induce mass loss. Despite the high temperatures (185 \({}^{\circ}\)C and 210 \({}^{\circ}\)C), the low mass losses may be related to the overall short cycles of thermal modification in laboratory-scale equipment, including the duration of maintaining the maximum temperature.