## 2 Sample Materials and Methods  
### Samples--Tropical Woods  
Four samples of wood dust from foreign wood species were used for this study. Samples of tropical wood were selected while considering their use in the production of floor coverings, furniture, and interior decorative items (Table 1).  
Cumaru (_Dipteryx odorata_), together with abiurana (_Pouteria guianensis_), garapeira (_Apuleia molaris_), jequitiba (_Cariniana_ sp.), Cedro (_Cedrela odorata_), angelim (_Parkia pendula_), angelim pedra (_Hymenopteraolbium excelsum_), and cerejeira (_Amburana acreana_) belongs to the group of Amazonian woody plants [30; 31]. The cumaru tree is very dense (950-1000 kg\(\cdot\)m\({}^{-3}\)), tough, highly durable, and resistant to cracking when exposed to sunlight. Therefore, it is suitable for solid flooring, stair treads, furniture, and pool decks [32]. Moreover, it is frequently found in the states of Acre, Amapa, Amazonas, Para, Rondonia, and Mato Grosso, as well as in neighboring countries like Guyana, Venezuela, Colombia, Bolivia, Peru, and Suriname [32].  
Padauk (_Pterocarpus soyauxi_) is moderately heavy, strong, and stiff, with exceptional stability. It is a popular hardwood among hobbyist woodworkers because of its unique color and low cost. It has a unique reddish-orange coloration, and the wood is sometimes referred to by the name 'Vermillion'. It is commonly used in flooring, musical instruments/objects, tool handles, furniture, other small particular wood objects, and as veneer [33].  
Ebony woods have many common names, such as Gabon Ebony, African Ebony, Nigerian Ebony, and Cameroon Ebony, and originate from the equator part of Western Africa. Heartwood (955 kg\(\cdot\)m\({}^{-3}\)) is  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Common Name 1** & **Scientific Name** & **Density (kg\(\cdot\)m\({}^{-3}\))** \\ \hline Cumaru & _Dipteryx odorata_ & 1075.69 \(\pm\) 10.04 \\ Padauk & _Pterocarpus soyauxi_ & 720.40 \(\pm\) 9.52 \\ Ebony & _Diospyros crassiflora_ & 960.00 \(\pm\) 7.46 \\ Marblewood & _Marmanroxylon racemosum_ & 1000.08 \(\pm\) 9.98 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Samples used in the experiment.  
usually jet-black, with little to no variation or visible grain. Occasionally, dark brown or grayish-brown streaks may be present. Ebony's common uses small items, such as piano keys, musical instrument parts, pool cues, carvings, and other small specialty items [34]. Ebony is highly valued in the Hindu religion as a building material [35], base material [36; 37], and for use in other items [38].  
Marblewood, also known as Angelim Rajado, is distributed from Northeastern South America. This heartwood (1005 kg\(\cdot\)m\({}^{-3}\)) is yellow to golden brown, with irregular brown, purple, or black streaks [39]. It is commonly used for tuned instruments/objects, flooring, carpentry, sliced veneer, and delicate furniture. [PERSON] et al. [40] introduced the possibility of using marblewood dust as a partial replacement for cement and sand in concrete.  
The basic samples (Figure 1a) of cumaru (\(152\times 38\times 38\) mm), Padouk (\(131\times 50\times 20\) mm), ebony (\(142\times 36\times 30\) mm), and marblewood (\(120\times 35\times 35\) mm) were made by a private wood company in Zilina (Slovakia) by a wood cutting saw (CNC Panel Saw Machine, Shandong, China) (Table 1). The moisture content of the basic samples was approximately 8-10%.