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Based on the previous study of the heat-treated wood at 0-3 mm surface layer, this study focuses on the transition of thermal modification intensity on 160-220 °C heat-treated poplar from surface to core layers. The color change was evaluated by CIELAB, and surface hardness was detected via Shore D (HD) and pressing ball method (HR); furthermore, the FT-IR was applied to detect the thermal degradation of wood components. The results show that the degradation of cell wall components in the surface layer of heat-treated poplar wood is greater than that in the core layers, and the thermal degradation intensity of the surface layer of the heat-treated poplar wood is greater than that of the other inner layers. Surface color and hardness properties of the heat-treated wood between S0 and S1-S5 test surfaces were significantly different under the same heat treatment conditions; the surface hardness showed an increasing trend, and the HR value of the H220-2 core layer was 105.71 % higher than that of the surface layer. Heat treatment temperature is the main factor affecting the property of wood surface, while the effect of duration is smaller. The hemicellulose content change was mainly related to the degradation intensity on heattreated wood at different locations. An accurate prediction model of surface color, hardness, and other properties of the heat-treated wood at different locations was established by Table Curve 3D software.

This study aimed to develop laminate flooring composite using a combination of wood and waste tire rubber (WTR). Plywood panels were produced by using beech (Fagus orientalis), alder (Alnus glutinosa), and poplar (Populus) veneers in a 7-ply configuration. To enhance the physical-mechanical properties of the panels, three loadings of nano-SiO2 (0, 2, and 4 wt%) along with 2 wt% of hexamethyldisilazane (HMDS) were added. Commercial urea-formaldehyde (UF) resin and methylene diphenyl diisocyanate (MDI) were used to bind the wood layers and rubber layers together. The mechanical properties, including modulus of rupture (MOR), modulus of elasticity (MOE), impact strength (IS), hardness strength (HS), and physical properties, such as density (D), water uptake (WU), and thickness swelling (TS), were evaluated. The results showed that increasing the WTR content led to improvements in the physical properties (D, WU, and TS), while negatively affecting the mechanical properties (MOR, MOE, IS, and HS) of the resulting panels. However, the addition of nano-SiO2 improved both the physical and mechanical properties (MOR, MOE, and HS) of the panels. Furthermore, it was observed that the mechanical properties were enhanced with increasing the number of beech layers, although the WU of panels decreased compared to panels made with alder and poplar. Overall, the improvement in the physical properties of the panels followed the order of the arrangement of rubber layers > nano-SiO2 content > veneer layers.

Wood heat treatment is an environmentally friendly method, and the heat-treated wood properties are closely related to thermal modification intensity. This study focuses on the 0-3 mm surface layer (SL) of poplar wood heat treated at 160~220 °C. The modification intensity, including surface color, hardness, chemical component and morphological changes of the SL, was evaluated. The findings of this research showed that the color difference of the poplar wood before and after heat treatment (ΔE*1) increased; the color difference between up-surface and down-surface of the SL (ΔE*2) also increased with the treatment temperature. Consequently, the surface hardness (HR) decreased with the increase of treatment intensity. When the treatment temperature was higher than 160 °C, the up-surface and down-surface of the SL were statistically different in color. Chemical component analysis revealed that the heat treatment degrades wood components, especially the hemicellulose, and correlation analysis showed a significant correlation between the change rate of hemicellulose and the ΔE*1 or HR value; the prediction functions have been established at a high confidence level of 0.99. Overall, the thermal modification intensity of the heat-treated surface layer (SL) of poplar wood varies, and the HR and ΔE*1 value could be used to characterize and predict the modification intensity and degree of thermal degradation of the surface layer of heat-treated poplar wood.

This study investigated the mechanical properties of beech (Fagus sylvatica L.) and fir (Abies alba) wood from Bosnia and Herzegovina under outdoor exposure. Samples were exposed for 3-month exposure to assess bending strength, color changes, and surface quality. Results showed outdoor exposure negatively affected mechanical properties, particularly in samples with extended finger joints, causing significant surface cracks in uncoated samples. Beech wood exhibited notable color changes under exposure, with approximately 50% darkening without coating compared to 25% under covered conditions. Coated samples displayed minimal color changes, affirming the efficacy of surface treatment. Fir wood exhibited a roughness of 8.264 μm, while beechwood average roughness increased from 6.767 to 13.916 μm after exposure, with micro-pore development affecting water performance. Microscopic analysis identified prevalent fungal colonies, including Penicillium, Aureobasidium, Sclerophoma, and Chaetomium, underscoring their role in organic matter decomposition. This study highlights the importance of wood exposure and treatment selection for various applications. [ABSTRACT FROM AUTHOR]

Background: Focusing on the health and wellness within educational settings is essential, as it plays a vital role in measuring the effectiveness of educational processes. Given the correlation between self-compassion and benefits of empathy on academic well-being, the present study investigated the mediating role of academic buoyancy in high school students. Methods: Using a descriptive-correlational approach, structural equation modeling (SEM) was employed to analyze the interplay between variables. Through multistage cluster sampling method, 384 high school students were selected between February and April 2023 in Ahvaz, Iran. The participants were asked to fill out School Related Well-Being Scale (SWBS), Self-Compassion Scale (SCS), Empathy Assessment Scale (EAS), and Academic Buoyancy Scale (ABS). The proposed model was evaluated using SEM. Statistical analysis was performed using SPSS Amos version 25. Results: Significant positive correlations were found between self-compassion and academic well-being (r=0.22, P=0.008), as well as between self-compassion and academic buoyancy (r=0.37, P=0.001). A positive correlation was also observed between the benefits of empathy and academic buoyancy (r=0.36, P=0.001). Furthermore, a significant positive correlation existed between academic buoyancy and academic well-being (r=0.59, P=0.001), along with significant indirect paths through academic buoyancy to academic well-being (P=0.010). Conclusions: The study findings supported the goodness of fit of the proposed model, suggesting its potential utility in developing interventions to enhance students' academic well-being. [ABSTRACT FROM AUTHOR]

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This study aimed to investigate the water absorption capacity of thermally modified and non-modified spruce and blue-stained spruce wood. The wettability of wood depends on various factors, including its type, density, porosity, and surface treatment. Wood can swell and become distorted when exposed to water or humidity, impacting its structural integrity. Hence, it is crucial to consider the water and water vapour uptake in the wood when choosing materials for applications that are likely to be exposed to moisture. Various moisture absorption tests were conducted to assess water absorption capacity, including short-term and long-term water absorption and water vapour absorption. The results showed a significant difference in the long-term exposure to water, which was related to the density of the wood. The study examined the influence of thermal treatment on the physical properties of wood and observed significant variations in mass change due to coating, indicating differences in adhesion among different wood types. Vacuum-treated blue-stained Norway spruce demonstrated higher adhesion (5%-15%) compared to air-treated samples. Furthermore, cohesion tests revealed lower cohesion force in blue-stained Norway spruce (approximately 20%-30%) compared to Norway spruce. The study also used industry-standard tests to investigate the adhesion and cohesion of nano-coatings on wood surfaces. The results provided valuable information on the properties of coatings applied to wood, which is vital in protecting and decorating wood while also providing preventive protection against wood pests, weathering, and mechanical influences. Wood modification in vacuum involves subjecting the wood to a low-pressure environment to remove air and moisture, allowing for deeper and more uniform penetration of treatment chemicals. In contrast, wood modification in air relies on the natural circulation of air to facilitate the absorption of chemical treatments, without the need for a vacuum chamber. [ABSTRACT FROM AUTHOR]

In this study, the mechanical characteristics of Norway spruce wood (Picea abies) from Bosnia and Herzegovina were investigated by thermal treatment at three different temperatures (specifically, 180, 190, and 210°C) and treatment durations (namely, 2, 3, and 4 hours). For this purpose, the maximum 4-point bending force, the modulus of elasticity in bending, the compression strength parallel to the grain, and the compression strength perpendicular to the grain in treated and untreated specimens were evaluated. Results indicated that the relationship between temperature and duration modification affects the mechanical properties of wood specimens. The results revealed that the relationship between temperature and duration modification influenced the mechanical properties of the wood samples. Specifically, in terms of compression strength, it was observed that the heattreated specimens exhibited improved mechanical properties compared to the unmodified specimens. However, for the maximum 4-point bending force and modulus of elasticity, the results indicated a decrease in mechanical properties. [ABSTRACT FROM AUTHOR]

In this paper, the natural durability of commercial wood (beech wood) was studied by measuring its water exclusion efficacy and durability against fungi. This information was utilized in the Meyer-Veltrup model to calculate the resistance dose. The results showed that Fagus orientalis (Lipsky) heartwood and sapwood were less durable (DC 4-5). After one hour of immersion, the water uptake in F. orientalis sapwood was 19%, slightly more than that determined with F. orientalis heartwood (18.9%). Water immersion after 24 h was highest for F. orientalis sapwood (45.4%), followed by F. orientalis heartwood (40.9%). Up to 54.2% median MLF on F. orientalis heartwood and up to 61.1% median MLF on F. orientalis sapwood were attributed to the white fungus T. versicolor. In contrast, the lowest median MLF was caused by F. orientalis heartwood and sapwood by the white fungus H. fragiforme. 35.4% median MLF on F. orientalis was caused by terrestrial microcosms. Based on the resistance model, the first signs of fungal decay on F. orientalis heartwood and sapwood wood will develop after 312 and 294 days of favorable conditions, respectively. [ABSTRACT FROM AUTHOR]

This study aims to improve the value of fast-growing wood and extend the heat-treated wood utilization using inorganic calcium carbonate (CaCO3) crystals via an in-situ synthesis method. CaCl2 and Na2CO3 solutions with a concentration ratio of 1:1 were successively introduced into the thermally modified poplar wood obtained by steam heat treatment (HT) at 200°C for 1.5 and 3 h, resulting in the in-situ synthesis of CaCO3 crystals inside the heat-treated wood. The filling effect was best at the concentration of 1.2 mol/L. CaCO3 was uniformly distributed in the cell cavities of the heat-treated wood, and some of the crystals were embedded in the fissures of the wood cell walls. The morphology of CaCO3 crystals was mainly spherical and rhombic polyhedral. Three main types of CaCO3 crystals were calcite, vaterite, and aragonite. The HT of poplar wood at 200°C resulted in degrading the chemical components of the wood cell wall. This degradation led to reduced wood mechanical properties, including the surface hardness (HD), modulus of rupture (MOR), and modulus of elasticity (MOE). After CaCO3 was in-situ synthesized in the heat-treated wood, the HD increased by 18.36% and 16.35%, and MOR increased by 14.64% and 8.89%, respectively. Because of the CaCO3 synthesization, the char residue of the 200°C heat-treated wood samples increased by 9.31% and the maximum weight loss rate decreased by 19.80%, indicating that the filling with CaCO3 cannot only improve the mechanical properties of the heat-treated wood but also effectively enhance its thermal stability. [ABSTRACT FROM AUTHOR]

This article investigates the relationships between soil characteristics (physical and chemical) and wood properties of Persian oak in three different elevation sites. For this purpose, 27 trees were randomly chosen and cut in Zagros forests in western Iran. The test samples were prepared at the stem (breast height) to examine physical and biometrical properties. For each elevation site, four soil samples were obtained at a 0-20 cm soil depth under the canopy of each tree to measure soil properties, including clay, silt soil, sand soil, electrical conductivity, pH, nitrogen, phosphorus, potassium, and organic matter content. Then, the relationship of soil and wood properties was determined by principal component analysis. Results specified that there are a positive correlation between wood density and volumetric swelling with clay and available potassium. Moreover, the results revealed a positive correlation between fiber length, cell wall thickness, and fiber diameter with electrical conductivity, sand percentage, and total nitrogen content, respectively. [ABSTRACT FROM AUTHOR]

The aim of this study is to compare the changes in serum uric acid levels among preeclamptic pregnant women and healthy pregnant women. Two hundred and twenty-four (224) pregnant women were enrolled. Serum uric acid levels were analysed in the two groups at the time of referral and prior to the delivery. The mean uric acid in all pregnant women was 5.61 mg/dL. The mean uric acid in women with preeclampsia was 6.51 ± 1.53 and in normotensive women was 4.72 ± 1.58, which was seen significant. The mean age of the mother, gestational age and BMI were not significant with the levels of uric acid. The elevation in serum levels of uric acid increased the risk of preeclampsia by 1.98 folds. There is a significant increase in the serum levels of uric acid in pregnant women with preeclampsia as compared to normotensive women. This can be one of a significant indicator of preeclampsia. [ABSTRACT FROM AUTHOR]