Search Results (35)

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

The development of polymer binders with tailored functionalities and green manufacturing processes is highly needed for high-performance lithium–sulfur batteries. In this study, a readily hydrolyzable 3,9-divinyl-2,4,8,10-tetraoxaspiro-[5.5]-undecane is utilized to prepare a water-based binder. Specifically, the acrolein produced by hydrolysis undergoes in situ polymerization to form a linear polymer, while the other hydrolyzed product, pentaerythritol, physically crosslinks these polymer chains via hydrogen bonding, generating a network polymer (BTU). Additionally, gallic acid (GA), a substance derived from waste wood, is further introduced into BTU during slurry preparation, forming a biphenol-containing binder (BG) with a multi-hydrogen-bonded structure. This resilience and robust cathode framework effectively accommodate volumetric changes during cycling while maintaining efficient ion and electron transport pathways. Furthermore, the abundant polar groups in BG enable strong polysulfide adsorption. As a result, sulfur cathode with a high mass loading of 5.3 mg cm⁻² employing the BG (7:3) binder still retains an areal capacity of 4.7 mA h cm⁻² after 50 cycles at 0.1 C. This work presents a sustainable strategy for battery manufacturing by integrating renewable biomass-derived materials and eco-friendly aqueous processing to develop polymer binders, offering a green pathway to high-performance lithium–sulfur batteries. Full article

The increasing prevalence of microplastic (MP) pollution and the labor-intensive nature of existing identification methods necessitate improved large-scale detection approaches. Nile Red (NR) fluorescence, which varies with polarity, offers a potential classification method, but standardization of carrier solvents and fluorescence differentiation techniques remains lacking. This study evaluated eight NR-carrier solvents (n-hexane, chloroform, acetone, methanol, ethanol, acetone/hexane, acetone/ethanol, and acetone/water) across ten common MP polymers (HDPE, LDPE, PP, EPS, PS, PC, ABS, PVC, PET, and PA). Fluorescence intensity, Stokes shift, and solvent-induced polymer degradation were analyzed. The study also assessed HSV (Hue/Saturation/Value) color spaces for Stokes shift representation and MP differentiation. Fenton oxidation effectively quenched fluorescence in natural organic matter (e.g., eggshells, fingernails, wood, cotton) while preserving NR-stained MPs. Acetone/water [25% (v/v)] emerged as the optimal solvent, balancing fluorescence performance and minimal degradation. Full article

This paper explores the effects of the cessation of forest commodity exports and the implementation of an industrialization strategy in Gabon, drawing on traditional theories of regional growth. The creation of the Nkok Special Economic Zone (SEZ) in 2012, accompanied by its strategic location and significant infrastructure investments, illustrates the application of Rosenstein-Rodan’s “Big Push” and Douglass-North’s “export base” theories. These initiatives also led to a polarization process consistent with the work of Perroux and other theorists of unbalanced regional growth. The study assesses the impact of this SEZ on regions external to the SEZ and the macroenvironment during the period 2014–2022. It highlights the industrial and commercial mechanisms that promote agglomeration economies, technological diffusion, the creation of economic connections, and the structuring into “core-periphery” zones, in accordance with the concepts of Hirschman. The results show a strong positive correlation between industrial income, exports (excluding raw materials), and industrial production. However, the ban on the export of wood raw materials led to a negative relationship between industrial income and exports of these products. Furthermore, the local processing of forest products has promoted industrial diversification, generated new products, and gradually increased added value. The process of economic and geographical polarization is described as a transitional phase of imbalances whose long-term implications require in-depth studies, particularly in the context of countries in the South and underdeveloped environments. Full article

Wood blue staining is one of the most common wood defects, which commonly occurs in rubberwood and Masson pine. It not only affects the appearance of the wood, but also its properties. In this study, rubberwood from Xishuangbanna was examined. During the process, blue-stain fungi and endophytic fungi were isolated and identified. The antagonism of biocontrol strains against blue-stain fungi was studied, and their inhibitory effects were evaluated by inoculating the biocontrol strains on non-blue-stained rubberwood. The morphology and distribution of the strains on the wood were observed using polarized light and fluorescence microscopy, infrared spectroscopy, scanning electron microscopy (SEM–EDS), and X-ray diffraction (XRD). The effects of biocontrol strains on the blue stain of the wood were then evaluated. The results showed that at room temperature, the fungus causing the blue stain in rubberwood was identified as Lasiodiplodia theobromae, and the biocontrol strains of endophytic fungi isolated were Trichoderma koningii and Trichoderma reesei. It was found that T. reesei was more effective than T. koningii in inhibiting the development of L. theobromae. Based on these findings, T. reesei was suggested as a biocontrol strain for preventing and controlling blue stain in rubberwood. Full article

Extractives, which naturally evolve as fundamental defense mechanisms in wood against environmental stresses, hold an essential place in the field of wood conservation science. Despite their low content in woody substrates, extractives are chemically complex and can be extracted accurately by solvents with different polarities, covering key components such as aliphatic, terpenoid, and phenolic compounds. The application of solvent extraction allows for the effective recovery of these extracts from forestry waste, thereby creating new opportunities for their reuse in wood modification and enhancing the economic value and potential applications of forestry waste. In the wood industry, extractives not only act as efficient preservatives and photo-stabilizers, significantly improving the decay resistance and photodegradation resistance of wood, but also serve as ideal dyes for fast-growing wood due to their abundant natural colors, which lend the product a distinct aesthetic appeal. The aim of this paper is to provide a comprehensive review of the origin and distribution characteristics of wood extractives and to examine the impact of solvent selection on extraction efficiency. At the same time, the mechanism of extractives in enhancing wood decay resistance and slowing down photodegradation is deeply analyzed. In addition, specific examples are presented to illustrate their wide utilization in the wood industry. This is intended to provide references for research and practice in related fields. Full article

The presence of green areas in urbanized cities is crucial to reduce the negative impacts of urbanization. However, these areas can influence the signal quality of IoT devices that use wireless communication, such as LoRa technology. Vegetation attenuates electromagnetic waves, interfering with the data transmission between IoT devices, resulting in the need for signal propagation modeling, which considers the effect of vegetation on its propagation. In this context, this research was conducted at the Federal University of Pará, using measurements in a wooded environment composed of the Pau-Mulato species, typical of the Amazon. Two machine learning-based propagation models, GRNN and MLPNN, were developed to consider the effect of Amazonian trees on propagation, analyzing different factors, such as the transmitter’s height relative to the trunk, the beginning of foliage, and the middle of the tree canopy, as well as the LoRa spreading factor (SF) 12, and the co-polarization of the transmitter and receiver antennas. The proposed models demonstrated higher accuracy, achieving values of root mean square error (RMSE) of $3.86$ dB and standard deviation (SD) of $3.8614$ dB, respectively, compared to existing empirical models like CI, FI, Early ITU-R, COST235, Weissberger, and FITU-R. The significance of this study lies in its potential to boost wireless communications in wooded environments. Furthermore, this research contributes to enhancing more efficient and robust LoRa networks for applications in agriculture, environmental monitoring, and smart urban infrastructure. Full article

This study investigates the suitability of using caffeine-treated and untreated black cherry (Prunus serotina Ehrh.) wood as a polylactide filler. Composites containing 10%, 20%, and 30% filler were investigated in terms of increasing the nucleating ability of polylactide, as well as enhancing its resistance to microorganisms. Differential scanning calorimetry studies showed that the addition of caffeine-treated wood significantly altered the crystallization behavior of the polymer matrix, increasing its crystallization temperature and degree of crystallinity. Polarized light microscopic observations revealed that only the caffeine-treated wood induced the formation of transcrystalline structures in the polylactide. Incorporation of the modified filler into the matrix was also responsible for changes in the thermal stability and decreased hydrophilicity of the material. Most importantly, the use of black cherry wood treated with caffeine imparted antifungal properties to the polylactide-based composite, effectively reducing growth of Fusarium oxysporum, Fusarium culmorum, Alternaria alternata, and Trichoderma viride. For the first time, it was reported that treatment of wood with a caffeine compound of natural origin alters the supermolecular structure, nucleating abilities, and imparts antifungal properties of polylactide/wood composites, providing promising insights into the structure-properties relationship of such composites. Full article

The enhancement of the physical and mechanical properties and the anti-mildew performance of wood–plastic composites are of great significance for broadening their application field. In this research, bamboo fibers underwent treatments with safe, environmentally friendly bio-enzymes. Subsequently, a bamboo–plastic composite (BPC) was developed using the modified bamboo fibers and polyethylene. The effects of biological enzymatic treatments on the surface free energy, the chemical composition of the bamboo fibers, water resistance, thermal stability, bending performance, impact performance, and anti-mildew performance of the BPC samples were analyzed. This study revealed that treating bamboo powder with bio-enzymes (xylanase, lipase, laccase, pectinase, hemicellulase, or amylase) decreased the surface free energy and the polar components of the bamboo fibers while improving the surface O/C atomic ratio of the bamboo fibers. These enzyme treatments enhanced the water resistance, bending performance, and anti-mildew performance of the BPC samples. However, on the whole, the thermal stability of the composites decreased. Particularly, after hemicellulase treatment, the composites had the lowest water absorption, reflecting a decrease of 68.25% compared to the control group. With xylanase modification, the 24 h water absorption thickness swelling rate of the composites was the lowest, reflecting a decrease of 71.27% compared to the control group. After pectinase modification, the static bending strength and elastic modulus of the prepared composites were the highest, with an increase of 15.45% and 13.31%, respectively, compared to the unmodified group. After xylanase modification, the composites exhibited the best anti-mildew effect, with an anti-mold effectiveness of 74.67%. In conclusion, bio-enzyme treatments can enhance the physical and mechanical properties and anti-mildew performance of BPCs. This research provides a theoretical foundation for the preparation of high-performance wood–plastic composites. Full article

This study explores the effect of tannic acid on the corrosion of woodworking tool material W18Cr4V in a simulated wood environment. The weight loss method, potentiodynamic polarization, and electrochemical impedance spectroscopy were used to study the corrosion and the corrosion inhibition process of W18Cr4V in an environment of acetic acid solution with different concentrations of tannic acid. The results show that after continuous immersion for 20 h, low concentrations (1 wt% and 3 wt%) of tannic acid promoted the corrosion of W18Cr4V, while high concentrations (5 wt% and above) of tannic acid had a significant anti-corrosion effect, with a corrosion inhibition efficiency of about 64% for 10 wt% tannic acid. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy were used to further verify and elucidate the inhibition mechanism. It was found that tannic acid can form a dense and effective corrosion inhibition film composed of iron–tannin complexes on the surface of W18Cr4V. This study not only provides a new perspective on understanding the corrosion effect of tannic acid on woodworking tools but also offers new insights for developing effective bio-corrosion protection strategies. Full article

Rosin has a great influence on the bonding of Pinus massoniana wood, and surface modification is an important way to solve this problem. In this study, Pinus massoniana wood was treated by plasma, and the effects of plasma treatment on the bonding performance and surface characteristics were investigated. The results showed the following: (1) After plasma treatment, the contact angle of Pinus massoniana wood was significantly reduced and the surface energy was significantly increased from 28.42 × 10⁻⁷ to 74.75 × 10⁻⁷ J·cm⁻², and the surface wettability was also greatly improved. (2) Plasma high-energy particles experience simultaneous physical and chemical effects on the surface of Pinus massoniana wood. The former formed a micro-etched roughness on the wood surface and led to the increase in surface dispersion force, while the latter increased the aggregation and activity of polar groups on the wood surface and the degradation of some wood components and rosin, resulting in the increase in surface polar force and the enhancement of wettability. (3) After plasma treatment, the reactivity of wood was enhanced, and the cross-linking degree with adhesive and the heat release were increased. The bonding strength of Pinus massoniana wood could be improved: dry bonding from 5.08 to 5.38 MPa, boiling-water bonding strength from 4.12 to 4.53 MPa, cold-water bonding strength from 3.84 to 4.51 MPa, and the bonding stability and reliability of glued specimens were also improved. Full article

The surface of a bonding material plays a key role in the bonding performance of an adhesive. Herein, we evaluated the effect of substrate surface treatment methods (sandpaper polished, chemical oxidation, and coupling agent) on the adhesive properties of starch-based aqueous polymer isocyanate (API) wood adhesive during hygrothermal aging. The birch substrate was processed with three different surface treatments, and the change of surface was analyzed by X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared spectroscopy (FT-IR), and Energy Dispersive Spectroscopy (EDS) methods. The results showed that the surface treatment had a great influence on the change of the shear strength of glued wood under hygrothermal conditions, and the silane coupling agent treatment could effectively reduce the decrease in the compressive shear strength of the adhesive. An XPS analysis indicated that the chemical oxidation modified wood surface polarity, and the coupling agent treatment in the wood surface formed a transition layer. After hygrothermal aging treatment, due to the different surface treatment of adhesive joint surface binding energy, the internal water absorption rate of starch-based API adhesives exhibited different failure modes of the adhesive joint. These findings indicate that the surface treatment effectively improved the durability of the adhesive joints. Full article

Structural diversity is recognized as a complementary aspect of biological diversity and plays a fundamental role in forest management, conservation, and restoration. Hence, the assessment of structural diversity has become a major effort in the primary international processes, dealing with biodiversity and sustainable forest management. Because of prohibitive costs associated with the ground measurements of forest structure, despite their high accuracy, space-borne polarization coherence tomography (PCT) can introduce an alternative approach given its ability to provide a vertical reflectivity profile and spatiotemporal resolutions related to detecting forest structural changes. In this study, for the first time ever, the potential of space-borne PCT was evaluated in a broad-leaved Hyrcanian forest of Iran over 308 circular sample plots with an area of 0.1 ha. Two aspects of horizontal structure diversity, including standard deviation of diameter at breast height (${\sigma }_{dbh}$) and the number of trees ($N$), were predicted as important characteristics in wood production and biomass estimation. In addition, the performance of prediction algorithms, including multiple linear regression (MLR), k-nearest neighbors (k-NN), random forest (RF), and support vector regression (SVR) were compared. We addressed the issue of temporal decorrelation in space-borne PCT utilizing the single-pass TanDEM-X interferometer. The data were acquired in standard DEM mode with single polarization of HH. Consequently, airborne laser scanning (ALS) was used to estimate initial values of height $h_v$ and ground phase ${\phi }_0$. The Fourier–Legendre series was used to approximate the relative reflectivity profile of each pixel. To link the relative reflectivity profile averaged within each plot with corresponding ground measurements of ${\sigma }_{dbh}$ and $N$, thirteen geometrical and physical parameters were defined ($P1-P13$). Leave-one-out cross validation (LOOCV) showed a better performance of k-NN than the other algorithms in predicting ${\sigma }_{dbh}$ and $N$. It resulted in a relative root mean square error (rRMSE) of 32.80%, mean absolute error (MAE) of 4.69 cm, and R²* of 0.25 for ${\sigma }_{dbh}$, whereas only 22% of the variation in $N$ was explained using the PCT algorithm with an rRMSE of 41.56%. This study revealed promising results utilizing TanDEM-X data even though the accuracy is still limited. Hence, an entire assessment of the used framework in characterizing the reflectivity profile and the possible effect of the scale is necessary for future studies. Full article

Castanea sativa Mill. (Fagaceae) is a deciduous tree grown for its wood and edible fruits. Chestnut processing produces residues (burs, shells, and leaves) exploitable for their diversity in bioactive compounds in animal nutrition. In fact, plant-specialized metabolites likely act as rumen modifiers. Thus, the recovery of residual plant parts as feed ingredients is an evaluable strategy. In this context, European chestnut leaves from northern Germany have been investigated, proving to be a good source of flavonoids as well as gallo- and ellagitannins. To this purpose, an alcoholic extract was obtained and an untargeted profiling carried out, mainly by means of ultra-high-performance liquid chromatography/high-resolution tandem mass spectrometry (UHPLC-HR MS/MS) techniques. To better unravel the polyphenol constituents, fractionation strategies were employed to obtain a lipophilic fraction and a polar one. This latter was highly responsive to total phenolic and flavonoid content analyses, as well as to antiradical (DPPH^● and ABTS^+●) and reducing activity (PFRAP) assays. The effect of the alcoholic extract and its fractions on rumen liquor was also evaluated in vitro in terms of fermentative parameter changes and impact on methanogenesis. The data acquired confirm that chestnut leaf extract and the fractions therefrom promote an increase in total volatile fatty acids, while decreasing acetate/propionate ratio and CH₄ production. Full article

The work investigates the effects of CO₂ laser parameters (laser power and raster density) on wood mass loss in oak wood and impacts on its morphology, chemical structure, and surface properties (colour and hydrophilicity). The energy amount supplied onto the wood surface with a laser beam under different combinations of the irradiation parameters was expressed through a single variable—total irradiation dose. The mass loss was confirmed as linear-dependent on the irradiation dose. With the mass reduction, the roughness was enhanced. The roughness parameters Ra and Rz increased linearly with the mass loss associated with the increasing irradiation dose. The FTIR (Fourier transform infrared spectroscopy) spectroscopy also detected chemical changes in the main wood components, influencing primarily the wood colour space. Conspicuous discolouration of the engraved wood surface was observed, occurring just at the minimum laser power and raster density. The additional increasing of laser parameters caused a novel colour compared to the original one. The detected dependence of wood discolouration on the total irradiation dose enables us to perform targeted discolouration of the oak wood. The engraved surfaces manifested significantly better wettability with standard liquids, both polar and non-polar, and higher surface energy values. This guarantees appropriate adhesion of film-forming materials to wood. Identification of the changes in wood surface structure and properties, induced by specific CO₂ laser-treatments, is important for obtaining targeted discolouration of the wood surface as well as for the gluing or finishing of the surfaces treated in this way. Full article