Search Results (363)

Climate extremes threaten the resilience of Eucalyptus plantations, yet hybridization with drought-tolerant species may enhance stress tolerance. This study analyzed xylem anatomical and functional drought responses in commercial Eucalyptus grandis (GG) clones and hybrids: E. grandis × camaldulensis (GC), E. grandis × tereticornis (GT), and E. grandis × urophylla (GU1, GU2). We evaluated vessel traits (water transport), fibers (mechanical support), and wood density (D) in stems and branches. Theoretical stem hydraulic conductivity (k_Stheo), vessel lumen fraction (F), vessel composition (S), and associations with previous hydraulic and growth data were assessed. While general drought responses occurred, GC had the most distinct xylem profile. This may explain it having the highest performance in different irrigation conditions. Red gum hybrids (GC, GT) maintained k_Stheo under drought, with stable F and a narrower vessel size, especially in branches. Conversely, GG and GU2 reduced F and S; and stem k_Stheo declined for a similar F in these clones, indicating vascular reconfiguration aligning the stem with the branch xylem. Almost all clones increased D under drought in any organ, with the highest increase in red gum hybrids. These results reveal diverse anatomical adjustments to drought among clones, partially explaining their growth responses. Full article

A brick kiln was experimentally studied to measure the transient temperature of hot gases and the compressive strength of the bricks, using pine wood as fuel, in order to evaluate the thermal performance of the actual system. In addition, a transient combustion model based on computational fluid dynamics (CFD) was used to simulate the combustion of natural gas in the brick kiln as a hypothetical case, with the aim of investigating the potential benefits of fuel switching. The theoretical stoichiometric combustion of both pine wood and natural gas was employed to compare the mole fractions and the adiabatic flame temperature. Also, the transient hot gas temperature obtained from the experimental wood-fired kiln were compared with those from the simulated natural gas-fired kiln. Furthermore, numerical simulations were carried out to obtain the transient hot gas temperature and NOx emissions under stoichiometric, fuel-rich, and excess air conditions. The results of CO₂ mole fractions from stoichiometric combustion demonstrate that natural gas may represent a cleaner alternative for use in brick kilns, due to a 44.08% reduction in emissions. Contour plots of transient hot gases temperature, velocity, and CO₂ emission inside the kiln are presented. Moreover, the time-dependent emissions of CO₂, H₂O, and CO at the kiln outlet are shown. It can be concluded that the presence of CO mole fractions at the kiln outlet suggests that the transient combustion process could be further improved. The low firing efficiency of bricks and the thermal efficiency obtained are attributed to uneven temperatures distributions inside the kiln. Moreover, hot gas temperature and NOx emissions were found to be higher under stoichiometric conditions than under fuel-rich or excess of air conditions. Therefore, this work could be useful for improving the thermal–hydraulic and emissions performance of brick kilns, as well as for future kiln design improvements. Full article

Background/Objectives: Interstitial lung disease (ILD) is frequently complicated by pulmonary hypertension (PH), which is associated with reduced exercise capacity and poor prognosis. Early and accurate non-invasive detection of PH remains a clinical challenge. This study evaluated whether combining quantitative CT analysis of lung fibrosis with cardiac MRI-derived measures of right ventricular (RV) function improves the diagnostic accuracy of PH in patients with ILD. Methods: We retrospectively analyzed 72 ILD patients who underwent chest CT, cardiac MRI, and right heart catheterization (RHC). Lung fibrosis was quantified using a Gaussian Histogram Normalized Correlation (GHNC) software that computed the proportions of diseased lung, ground-glass opacity (GGO), honeycombing, reticulation, consolidation, and emphysema. MRI was used to assess RV end-systolic volume (RVESV), ejection fraction, and RV longitudinal strain. PH was defined as a mean pulmonary arterial pressure (mPAP) ≥ 20 mmHg and pulmonary vascular resistance ≥ 3 Wood units on RHC. Results: Compared to patients without PH, those with PH (n = 21) showed significantly reduced RV strain (−13.4 ± 5.1% vs. −16.4 ± 5.2%, p = 0.026) and elevated RVESV (74.2 ± 18.3 mL vs. 59.5 ± 14.2 mL, p = 0.003). CT-derived indices also differed significantly: diseased lung area (56.4 ± 17.2% vs. 38.4 ± 12.5%, p < 0.001), GGO (11.8 ± 3.6% vs. 8.65 ± 4.3%, p = 0.005), and honeycombing (17.7 ± 4.9% vs. 12.8 ± 6.4%, p = 0.0027) were all more prominent in the PH group. In receiver operating characteristic curve analysis, diseased lung area demonstrated an area under the curve of 0.778 for detecting PH. This increased to 0.847 with the addition of RVESV, and further to 0.854 when RV strain was included. Combined models showed significant improvement in risk reclassification: net reclassification improvement was 0.700 (p = 0.002) with RVESV and 0.684 (p = 0.004) with RV strain; corresponding IDI values were 0.0887 (p = 0.03) and 0.1222 (p = 0.01), respectively. Conclusions: Combining CT-based fibrosis quantification with cardiac MRI-derived RV functional assessment enhances the non-invasive diagnosis of PH in ILD patients. This integrated imaging approach significantly improves diagnostic precision and may facilitate earlier, more targeted interventions in the management of ILD-associated PH. Full article

This study proposes a novel LK-BP-AFPSO model for the nondestructive evaluation of wood mechanical properties, combining a backpropagation neural network (BP) with adaptive fractional-order particle swarm optimization (AFPSO) and Liang–Kleeman (LK) information flow theory. The model accurately predicts four key mechanical properties—longitudinal tensile strength (SPG), modulus of elasticity (MOE), bending strength (MOR), and longitudinal compressive strength (CSP)—using only nondestructive physical features. Tested across diverse wood types (fast-growing YKS, red-heart CSH/XXH, and iron-heart XXT), the framework demonstrates strong generalizability, achieving an average prediction accuracy (R²) of 0.986 and reducing mean absolute error (MAE) by 23.7% compared to conventional methods. A critical innovation is the integration of LK causal analysis, which quantifies feature–target relationships via information flow metrics, effectively eliminating 29.5% of spurious correlations inherent in traditional feature selection (e.g., PCA). Experimental results confirm the model’s robustness, particularly for heartwood variants, while its adaptive fractional-order optimization accelerates convergence by 2.1× relative to standard PSO. This work provides a reliable, interpretable tool for wood quality assessment, with direct implications for grading systems and processing optimization in the forestry industry. Full article

This study evaluated birch and oak ash extracts as alternative extractants for isolating humic substances (HSs) from peat and lignite. The effects of ultrasound intensity, extraction time, and temperature were optimized using a Box–Behnken design and validated statistically. The highest HSs yields were obtained from peat with oak ash extract (pH 13.18), compared to birch ash extract (pH 12.09). Optimal process parameters varied by variant, falling within 309–391 mW∙cm⁻², 116–142 min, and 67–79 °C. HSs extracted under optimal conditions were fractionated into humic acids (HAs) and fulvic acids (FAs), and then analyzed by elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR), and Cross-Polarization Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance Spectroscopy (CP/MAS ¹³C NMR). The main differences in HSs quality were influenced by raw material and fraction type. However, the use of birch ash extract consistently resulted in a higher proportion of carboxylic structures across all fractions. Overall, wood ash extract, especially from oak, offers a sustainable and effective alternative to conventional extractants, particularly for HSs isolation from lignite. Notably, HSs yield from lignite with oak ash extract (29.13%) was only slightly lower than that achieved with 0.5 M NaOH (31.02%), highlighting its practical potential in environmentally friendly extraction technologies. Full article

This study investigates the pyrolysis of construction, renovation, and demolition (CRD) wood waste to produce biochar, with a focus on its robustness, scalability, and characterization for energy and environmental applications. Pyrolysis conditions, including the temperature, biomass residence time (BRT), and feedstock mass, were varied to evaluate their effects on biochar properties. High-temperature biochars (B800) showed the highest fixed carbon (FC) (87%) and thermostable fraction (TSF) (96%) and the lowest volatile carbon (VC) (9%), with a high carbon content (92%), a large BET surface area (300 m²/g), and a high micropore volume (0.146 cm³/g). However, the hydrogen (0.9%) and oxygen (2.2%) content, Van-Krevelen parameters (H/C: 0.1; O/C: 0.02), and biochar yield (21%) decreased with increasing temperature. Moderate-temperature biochars (B600) have balanced physicochemical properties and yields, making them suitable for adsorption applications. Methyl orange dye removal exceeded 90% under the optimal conditions, with B600 fitting well with the Freundlich isotherm model (R² = 0.97; 1/n = 0.5) and pseudo-second-order kinetic model (R² = 1). The study highlights biochar’s suitability for varied applications, emphasizing the need for scalability in CRD wood pyrolysis. Full article

The standardization of physical and mechanical properties is critical for the large-scale application of engineered bamboo products. In this study, the distribution characteristics of density and modulus of elasticity (MOE) were systematically examined in a large sample of flattened bamboo boards. The density and MOE ranged from 0.46 to 1.12 g/cm³ and 5.60 to 22.18 GPa, respectively. Both exhibited a decreasing trend with increasing board thickness. Based on interquartile analysis, four density grades and five MOE grades were established. A strong positive correlation was identified between density and MOE, indicating that density—closely linked to fiber volume fraction—is the primary factor influencing mechanical performance. Notably, the graded bamboo boards demonstrated significantly higher modulus values than conventional wood veneers such as hemlock and poplar, highlighting their potential for high-performance structural applications. This study proposes a practical grading framework that contributes to the standardization and broader engineering utilization of flattened bamboo boards. Full article

Wood is a naturally abundant, biodegradable, and renewable material with significant potential as an alternative to petroleum-based materials. However, its inherent heterogeneity, anisotropy, and modest mechanical properties limit its application in high-performance structural uses. Delignification, a critical process in papermaking and biorefining, has emerged as a promising pretreatment technique to enhance the properties of wood for advanced subsequent applications. This process selectively removes lignin while preserving the aligned cellulose structure, thereby improving mechanical strength, dimensional stability, and potential for functionalization. Various delignification methods, including alkaline, acidic, and reductive catalytic fractionation, have been explored to optimize the wood’s structural and chemical properties. When combined with densification or impregnation, delignified wood exhibits superior mechanical performance, making it suitable for a range of applications, including structural materials, optical devices, biomedical applications, and energy storage. This detailed review examines the chemistry and mechanisms of delignification, its impact on the physical and mechanical properties of wood, and its role in developing sustainable, high-performance bio-based materials. Furthermore, challenges and future opportunities in delignification research are discussed, highlighting its potential for next-generation wood-based innovative applications. Full article

This study examines the seasonality of Black Carbon (BC) and Brown Carbon (BrC) spectral absorption characteristics at a continental background site (Kozani) in southern Balkans (NW Greece). It aims to assess the seasonality and impact of different sources on light absorption properties, BC concentrations, and the fraction of BrC absorption. Moderate-to-low BC concentrations were observed, ranging from 0.05 µg m⁻³ to 2.44 µg m⁻³ on an hourly basis (annual mean: 0.44 ± 0.27 µg m⁻³; median: 0.39 µg m⁻³) with higher levels during winter (0.53 ± 0.33), reflecting enhanced emissions from residential wood burning (RWB) for heating purposes. Atmospheric conditions are mostly clean during spring (MAM) (BC: 0.34 µg m⁻³), associated with increased rainfall. BC components associated with fossil fuel combustion (BC_ff) and biomass burning (BC_bb), maximize in summer (0.36 µg m⁻³) and winter (0.28 µg m⁻³), respectively, while the absorption Ångstrôm exponent (AAE_370–880) values ranged from 1.09 to 1.93 on daily basis. The annual mean total absorption coefficient (b_abs,520) inferred by aethalometer (AE33) was 4.09 ± 2.65 Mm⁻¹ (median: 3.51 Mm⁻¹), peaking in winter (5.30 ± 3.35 Mm⁻¹). Furthermore, the contribution of BrC absorption at 370 nm, was also high in winter (36.7%), and lower during the rest of the year (17.3–29.8%). The measuring station is located at a rural background site 4 km outside Kozani City and is not directly affected by traffic and urban heating emissions. Therefore, the regional background atmosphere is composed of a significant fraction of carbonaceous aerosols from RWB in nearby villages, a characteristic feature of the Balkan’s rural environment. Emissions from the lignin-fired power plants, still operating in the region, have decreased during the last years and moderately affect the atmospheric conditions. Full article

This paper aims to develop a rheological model with fewer parameters that accurately describes the primary and secondary creep behavior of wood materials. The models studied are grounded in Riemann–Liouville fractional calculus theory. A comparison was conducted between the constant-order fractional Zener model and the variable-order fractional Maxwell model, with four parameters each. Using experimental creep data from four-point bending tests on two tropical wood species, along with an optimization algorithm, the variable-order fractional model demonstrated greater effectiveness. The selected fractional derivative order, modeled as a linearly increasing function of time, helped to elucidate the internal mechanisms in the wood structure during creep tests. Analyzing the parameters of this order function enabled an interpretation of their physical meanings, showing a direct link to the material’s mechanical properties. The Sobol indices have demonstrated that the slope of this function is the most influential factor in determining the model’s behavior. Furthermore, to enhance descriptive performance, this model was adjusted by incorporating stress non-linearity to account for the effects of the variation in constant loading level in wood. Consequently, this new formulation of rheological models, based on variable-order fractional derivatives, not only allows for a satisfactory simulation of the primary and secondary creep of wood but also provides deeper insights into the mechanisms driving the viscoelastic behavior of this material. Full article

An environmentally friendly and rational way of using wood waste is by introducing it into composite compositions. This paper investigates the use of wood chips from 10 to 60% for creating a thermal insulation composite. Prepared wood chips of various fractions were mixed with the sapropel/gypsum mixture. The composite with wood chips and a mixed sapropel/gypsum binder was hardened without thermal curing. Gypsum was added to absorb water from the sapropel and to give the composite its initial strength. Hydrated lime was used to improve the compressive stress of the binding material. The composite density varied from 400 to 1050 kg/m³, thermal conductivity varied from 0.0912 to 0.193 W/(m·K), and compressive stress varied from 0.2 to 7.9 MPa. The density of the composite and the studied properties depended on three factors: the ratio of sapropel to gypsum, the ratio of wood chips to binder, and the level of compaction. The content of sapropel/gypsum varied from 10 to 90%, the ratio of wood chips to binder varied from 0.5 to 1.5, and the compaction level varied from 16 to 40% according to the initial height of the mould. The main characteristics of the prepared composites with different sapropel/gypsum and wood chip ratios were determined. The density, compressive stress, and thermal conductivity results were statistically analysed. Full article

The environmental impact of livestock by-products presents significant challenges, particularly in regions with intensive farming and high pollution levels, such as the Po Valley. This study evaluated the effectiveness of biochar and wood vinegar in reducing gaseous emissions during the laboratory-scale storage of livestock slurry, digestate, and liquid fractions. Various types and applications of biochar, both with and without wood vinegar, were tested across three independent incubation periods of varying durations. The results showed that ammonia (NH₃) emissions were lower from slurry compared to raw digestate and the liquid fraction, while methane (CH₄) emissions exhibited the opposite trend. Pyrolysis biochar effectively reduced NH₃ emissions by 47% on average when applied as a 5 cm surface layer. However, its effectiveness was inconsistent when mixed into the material or when produced via gasification. Biochar activated with wood vinegar significantly reduced NH₃ emissions from both slurry and digestate by 61%, but it also led to increased emissions of CH₄ and CO₂. Nitrous oxide (N₂O) emissions were detected only after at least one month of incubation and were higher when biochar was used as a cover alone or when activated with wood vinegar. Overall, applying biochar as a cover and activating it with wood vinegar proved effective in reducing NH₃ emissions during the storage of livestock by-products. However, the effectiveness varied significantly depending on the type of biochar and its method of application, particularly with respect to CH₄ emissions, highlighting the need for careful consideration when using wood vinegar-activated biochar. Full article

During the conventional biomass fractionation, the degradation and dissolution of lignin and hemicellulose result in a complex extract which remains very challenging for the thorough separation and purification of a wide variety of fractionated products, limiting their further utilization. Herein, we proposed a facile and efficient strategy for fractionating biomass and simultaneously in situ converting of both lignin and hemicellulose into single products using a formic acid–phloroglucinol system. The introduced phloroglucinol could react with lignin fragments and hemicellulose-derived products, and the generated intermediate product from hemicellulose can be further condensed with lignin fragments, finally forming single lignin-based functional biopolymers containing heterocyclic structures. Only small amounts of hemicellulosic derivatives, such as oligosaccharides, monosaccharides, furfural, and 5-HMF, were detected in the extracted solution, indicating a highly directional and effective in situ conversion process of hemicellulose. The constructed specific structures on fabric surfaces by using the chelation between lignin-based functional biopolymers and metal ions achieved the preparation of functional fabrics with stable hydrophobicity. The dynamic contact angle of water droplets on the surface of prepared fabric only decreased from 122° to 116.8° over 30 min. This work strategy provides an ideal route to maximize the utilization of both lignin and hemicellulose without involving complex separation and purification procedures. This strategy is the first demonstration of using the targeted fractionation system to achieve the simultaneous conversion of hemicellulose and lignin into single functional biopolymers directly from lignocellulosic biomass. Full article

The rational use of wood waste allows the saving of forest resources and contributes to the reduction of the greenhouse effect. Three types of wood waste were used in this work: packaging (W), demolition and furniture construction (PLY), and door production (DW). The work performed an analysis of the granulometric composition of the wood waste and assessed the size, shape, and composition of the wood particles. The particle size was in the range of 0–20 mm, but the quantitative proportion of particles of different sizes in waste of different nature and shape was different. All wood particles were thermochemically treated to reduce the amount of dust and soluble particles and to increase the surface roughness of the wood particles to ensure better adhesion parameters with the binder. The binder used was biopolyurethane. Engineered wood composites (EWC) were formed from biopolyurethane and wood waste in a 50:50 ratio to evaluate compressive and bending strength. The strength values showed that all wastes were suitable for forming composites, but the size of the particles affected the magnitude of these values. The highest compressive stress of 11.7 MPa was obtained from composites using 0–5 mm PLY waste, while the lowest stress of 5.2 MPa was obtained from 0–20 mm W waste. In this case, the size of the wood waste particles affected not only the compressive stress but also the density of the composite. The analysis of the composite densities showed that 84.1% of the variation in the total density values was determined by the sample fraction, particle length-width ratio, angularity and sharpness and 15.9% by other factors that were not evaluated. For flexural strength, particle size and nature did not show a clear tendency, and values ranged from 7.2 to 11.5 MPa. The thermochemical treatment method of the wood particles had no or only a slight effect on the strength characteristics of the engineered wood composite. Full article

This study investigates the biodegradation behavior of poly(butylene succinate) (PBS) copolyesters containing dilinoleic acid (DLA) co-monomeric units and wood flour (WF) as a filler. PBS-DLA is a segmented thermoplastic elastomer (TPE), where the soft amorphous phase is formed by DLA ester segments, while the hard phase consists of crystallizable PBS domains. Wood–plastic composites (WPCs) were prepared with WF at weight fractions of 10%, 20%, 30%, and 40% wt. and analyzed in terms of surface morphology, chemical structure, mechanical performance, and thermal stability before and after biodegradation in soil conditions. The results of microscopic analysis confirmed that the PBS-DLA copolymer and its composites undergo surface biodegradation as manifested by increased surface roughness and microcrack formation, particularly in composites with a higher WF content. ATR FT-IR spectroscopy indicated oxidation and hydrolysis, supporting the hypothesis of progressive surface erosion. Mechanical tests showed a decline in tensile strength and elongation at break, with the most pronounced changes in composites containing 20% WF. Thermal analysis (DSC, DMTA, and TGA) confirmed that the PBS-DLA copolymer retains its thermoplastic elastomeric behavior after a 3-month biodegradation experiment. The storage modulus (E′) remained stable, while only minor variations in melting and crystallization temperatures were observed. These findings reinforce the hypothesis of surface erosion rather than a bulk degradation mechanism. Given their biodegradability and retained thermoplastic behavior, WPC composites based on PBS-DLA copolyester could be promising for eco-friendly applications where controlled degradation is desirable, such as in packaging, agriculture, or biodegradable consumer goods. Full article