Volume 19 Issue 4

In recent years, forest fires have become increasingly common, but also more damaging phenomena. These aspects are reflected in significant economic losses that affect the quality and quantity of wood volumes that can be used for industrial processing. For this reason, knowing the quality of the wood is important, especially in fire-affected trees. Because visual analyses cannot always reflect the quality of the wood inside the trunk, the present research aimed to evaluate the extent to which modern techniques based on the transfer of sounds can identify internal wood defects. In this sense, 42 tomograms made from beech trees affected by a litter fire were compared with the relative resistances of the wood to drilling and with the real condition of the wood inside the trunk, as made visible through the growth cores taken with a Pressler drill. From the cumulative interpretation of the results, it was found that the trees affected by the fire have serious defects, which lead to the downgrading of the wood and are not reproduced by the tomograph to their true extent. Conversely, sound transfer speeds through wood are influenced by the presence of beech red heartwood, which leads to an increase in sound transfer speeds through wood, and that can alter the accuracy of the tomogram.

To promote adsorption capacity of biochar as engineering material, pinewood biochar (PC) and bamboo biochar (BC) were prepared by slow pyrolysis (700 °C) and then directly irradiated with UV light at room temperature. The elemental analysis, SEM, FTIR, XPS, and Boehm titration measurements showed that UV irradiation significantly increased the BET surface area, porosity, and surface oxygen functional groups of the biochar. After UV treatment, the BET surface areas of PC and BC were increased by 63.0% and 217%, while the amount of total (acidic) groups increased by 62.0% (155%) and 24.9% (28.2%), respectively. FTIR and XPS measurements suggested that photochemical reactions, including photodegradation and photooxidation processes, may play primary roles in altering biochar the pore structure and surface functional groups of biochar. The Langmuir model capacities (q_max) of modified PC and BC were increased by 94.5% and 50.5% for Pb (II), 18.5% and 13.7% for Cd (II), respectively, compared to their unmodified counterparts. This study examined the effects of UV irradiation on the surface properties of biochar and demonstrate its potential as an effective, simple, and green method for functionalizing biomass material.

The increasing rates of illicit behaviors, particularly financial crimes, e.g., bank fraud and tax evasion, adversely affect national economies. In such cases, using nondestructive methods, scientists must evaluate relevant documents carefully to preserve their value as evidence. When forensic laboratories analyze paper as evidence, they typically investigate its origin and date of manufacture. If a document’s date is earlier than the earliest availability of the paper used in its creation, then this anachronism indicates that the document has been backdated. This study investigated weave marks and drainage marks for forensic purposes. Machine learning models for forensic document examination were developed and evaluated. The partial least squares discriminant analysis (PLS-DA), support vector machine (SVM), and artificial neural network (ANN) classification models achieved F1-scores of 0.903, 0.952, and 0.931, respectively. In addition, to enhance model effectiveness and construct a robust model, variables were selected using the VIP scores generated by the PLS-DA model. As a result, the SoftMax classifier in the ANN model maintained its performance with an F1-score of 0.951 even with a 50% reduction in the number of input variables.

Synergistic effects of herbicidal rice husks and pyrolysis liquid from waste wood-based panels were studied relative to the germination of three common weed species in a tea plantation. The pyrolysis liquid consisted of various organic acids, phenols, alcohols, ketones, and nitrogen compounds, with organic acids accounting for up to 46.8% of the content. Three seeds of smooth crabgrass (Digitaria ischaemum), annual fleabane (Erigeron annuus), and hedge-parsley (Torilis scabra (Thunb.) DC) were treated with 2000 and 4000 L/ha of pyrolysis liquid, as well as 50, 100, and 200 m³/ha of pyrolysis liquid as a cover material. The pre-emergence herbicide tests demonstrated that the combination of rice husks and pyrolysis liquid effectively inhibited seed germination and aboveground biomass of the weeds. The weed control effect increased with the increase in the amount applied. The combination of rice husks (200 m³/ha) and pyrolysis liquid (4000 L/ha) exhibited the highest weed control efficacy, reducing seed germination and aboveground biomass by 69.1%, 79.5%, and 97.6% for smooth crabgrass, annual fleabane, and hedge-parsley, respectively. Discarded furniture materials and rice husks can both be used as sustainable materials for weed control, offering a fresh approach to the efficient utilization of waste materials.

Finger joints are one of the most important and widely used joints in the wood and wood products industry. The design, type of construction, and the type of glue used, etc., are the most important things in this joint that determine its final quality. In this research, the effect of cellulose nanofiber and nanoclay in polyvinyl acetate (PVA) glue at levels of 0, 0.4, and 1.5% in finger joints with lengths of two fingers of 5 and 10 mm was investigated by the free vibration in free-free beam method. In joints without nanoparticles, finger joints with a finger length of 10 mm had better acoustic properties than joints with a finger length of 5 mm, except for the acoustic conversion efficiency factor. The results showed that by adding cellulose nanofiber (CNF) and nanoclay in both finger lengths of 5 and 10 mm at both 0.4% and 1.5% levels, the dynamic modulus of elasticity, elastic stiffness, acoustic coefficient, and acoustic conversion efficiency increased significantly, while the damping factor values showed a significant decrease. In general, the effect of CNF on the acoustic properties of both types of joints was better than that of nanoclay.

The antioxidant properties of Ainsliaea acerifolia, a wild edible plant, were examined by ultrasonic-assisted ethanol extraction methods. The primary objective was to optimize the extraction conditions and accurately predict antioxidant activities using advanced machine learning models. The extraction conditions were optimized using Response Surface Methodology (RSM). Various parameters, including temperature, extraction time, and ethanol concentration, were adjusted to maximize antioxidant activity. The optimal conditions identified were a temperature of 68 °C, an extraction time of 86 min, and an ethanol concentration of 57%. Under these conditions, the extracts exhibited the highest antioxidant activity. To enhance the predictive accuracy of antioxidant activity, an XGBoost (XGB) model was employed. The XGB model performance was evaluated and compared with the RSM model. The XGB model achieved an R² value of 94.71%, significantly outperforming the RSM model by 12.8%. This highlights the superiority of the XGB model in predicting antioxidant activities based on the given extraction parameters. Additionally, the study developed a graphical user interface (GUI). This GUI allows researchers and industry experts to input extraction conditions and obtain quick, accurate predictions of antioxidant activity.

A novel method for forming composite materials was investigated by incorporating activated carbon powder (ACP) as a reinforcing agent within a polylactic acid (PLA) matrix, utilizing the hand layup fabrication technique. The composite materials were synthesized by varying the weight percentages of the matrix and reinforcements, encompassing pure PLA as well as ratios of 90:10, 80:20, 70:30, 60:40, and 50:50. PLA is recognized for its biocompatibility and favorable thermomechanical properties, similar to conventional plastics. The incorporation of activated carbon powder, known for its remarkable aspect ratio, proved highly advantageous, yielding exceptional mechanical properties. Analysis revealed that the composite with a ratio of 90:10 wt% of carbon powder to PLA demonstrated significant improvements in tensile strength (26.8%), flexural strength (26.37%), impact strength (61.1%), compression strength (25%), and hardness (45.8%). Additionally, thermal analysis showed that the 90:10 wt% composite exhibited minimal weight loss and maximum heat flow sustainability at approximately 600 °C compared to other composite combinations. Morphological examination using field emission scanning electron microscopy unveiled a uniform distribution of activated carbon powder reinforcement within the matrix, actively contributing to the enhanced mechanical properties of the composite.

Nocardiopsis sp. strain LC-9 was isolated from freshwater sediments and explored for its varied bioactive traits. Initially, ethyl acetate extract of strain LC-9 at varied concentrations showed pronounced antibacterial activities. After column chromatography, fraction F2 and F3 of the extract were identified as prominent fractions in terms of antimicrobial activities with low minimum inhibitory concentration values. Antioxidant activities of fraction F2 and F3 revealed remarkable scavenging of free radicals with low IC₅₀ values (DPPH – 417.86 ± 0.24 μg/mL, ABTS – 431.6 ± 0.90 μg/mL, and FRAP – 404.36 ± 0.18 μg/mL). Fractions F2 and F3 were further characterized by UV spectrum, Fourier transform infrared spectroscopy, nuclear magnetic resonance, and liquid chromatography-mass spectrometry, and were identified as Antimycin A and 4-hydroxybenzoic acid. The compounds were further tested for anticancer activity against MCF-7 cells. The MTT assay showed reduced viability of MCF-7 cells with an increase in concentration of compounds. The IC₅₀ values for Antimycin A and 4-hydroxybenzoic acid were 9.6 ± 0.7 μg/mL and 20.8 ± 0.4 μg/mL, respectively. Staining techniques confirmed the apoptosis mechanism. Finally, molecular docking (against targeted proteins of bacteria, fungus, and cancer cells) and molecular dynamics confirmed the pharmaceutical efficacy of the purified compounds.

This study investigated the nutritional components of Castanopsis hystrix seeds and evaluated their potential commercial value, regarding multi-function management of C. hystrix plantations. The following nutritional components of Castanopsis hystrix seeds were determined according to national standards: starch, fat, protein, reducing sugars, and amino acids.  The chemical composition of their 50% benzene-alcohol(v/v) extracts was analyzed by GC-MS. Results showed that the contents of water, starch, fat, protein, and reducing sugar in the seeds were 36.08%, 68.11 g/100g, 0.3 g/100g, 3.98 g/100g, and 0.75 g/100g, respectively. The total amino acid content in the seeds is 3.42 g/100g, containing 16 kinds of amino acids, with 8 essential amino acids, which amount to 1.09g/100g. The amino acid SRC value was 84.02, indicating high nutritional value. A total of 26 compounds were identified in the extract of these seeds, with the highest content of aldehydes. The main compounds were 5-hydroxymethylfurfural (23.37%), melezitose (15.88%), palmitic acid (9.04%), and stearic acid (5.23%). The above analysis indicates that Castanopsis hystrix seeds have high nutritional value, as well as potential antioxidant and anti-tumor properties, which may have the potential to be used in food and medicine fields, with broad application prospects.

Hemicellulose is a renewable and environmentally friendly biomass polysaccharide. However, because of the low polymerization degree, conventional hemicellulose-based hydrogels often have poor mechanical properties, severely restricting their potential applications. This study involved preparation of a novel high-strength conductive hemicellulose-based composite hydrogel, modulated by a Na₂SO₄ solution. The hydrogel matrix with a physicochemical double cross-linking structure was created by adding polyvinyl alcohol to the chemically crosslinked networks of gelatin and dialdehyde xylan (DAX) to improve the enhancing effect. After being soaked in a 1 M Na₂SO₄ solution for 24 h, the composite hydrogel’s network structure was thicker, as revealed by scanning electron microscopy. Its tensile breaking strength (3.02 MPa) and elongation (330.95%) were much higher than those prior to the treatment. Energy dispersive spectroscopy and X-ray diffraction confirmed that the composite hydrogel had a considerable amount of Na⁺ and SO₄^2- uniformly dispersed throughout. Additionally, the ionic conductivity of the composite hydrogel was measured at 5.4 × 10^-3 S/m, indicating a potential use in the field of super-capacitors.