Volume 16 Issue 1

Rays are an important anatomical feature in tree species identification. They are found in certain proportions in trees, which vary for each tree. In this study, the U-Net model is adopted for the first time to detect wood rays. A dataset is created with images taken from the wood database. The resolution of microscopic wood images in tangential section is 640×400. The input image for training is divided into 32×32 image blocks. Each pixel in the dataset is labeled as belonging to the ray or the background. Then, the dataset is increased by applying scale, rotation, salt-and-pepper noise, circular mean filter, and gauss filter. The U-Net network created for ray segmentation is trained using the Adam optimization algorithm. The experimental results show that the ray segmentation accuracy in testing is 96.3%.

Microwave modification of activated coke is reported as a green and simple route to improve its synergistic desulfurization and denitrification. The results showed that microwave irradiation improved the specific surface area and pore volume, decreased the pore size, and activated the surface functional groups of the activated coke. Under the conditions of a microwave power of 500 W and a modification time of 30 min, the specific surface area was increased from 185.9 m2/g to 351.7 m2/g, the pore volume increased from 0.042 m3/g to 0.111 m3/g, and the characteristic peak strengths of C=C and -OH drastically increased. When the reaction temperature was 140 °C and the O2 concentration was 10% (by volume), the desulfurization and denitrification efficiency were maintained at levels greater than 90% and 80% for 30 min and 15 min, respectively. The C-O content increased, and the C=C and -OH content decreased after undergoing desulfurization and denitrification. The desulfurization and denitrification products were primarily sulfate and nitrate. This provides theoretical support for the application of microwave modified active coke in low temperature desulfurization and denitrification.

Modification of Pinus yunnanensis using SiO2–TiO2 was carried out via the sol–gel method. The aim was to improve the hydrophobicity, aging resistance, and photocatalysis of the wood surface via the formation of new chemical bonds with penetrated SiO2 and TiO2. The air-dried P. yunnanensis wood underwent penetration, gelation, aging, and drying. The wood was exposed to high temperatures for modification, and its microstructure, composition, photodegradability, resistance to aging, dimensional stability, and hydrophobicity were then determined. The results indicated that during modification, SiO2–TiO2 gel was generated in the wood, and the content of the gel increased as penetration time was extended. No structural change in the wood was observed. Meanwhile, chemical bonds were formed among SiO2, TiO2, and wood. The contact angle of the modified wood increased noticeably relative to that of unmodified wood. This increase indicated a noticeable increase in the hydrophobicity of the wood surface. The modified wood exhibited high photocatalytic degradation; however, its durability was not evident. The water absorption and thickness swelling of the modified wood markedly increased. After ultraviolet-aging resistance testing, the color change in the surface of the modified wood was noticeably less than that of the unmodified wood.

In the last decades, a new phenomenon has arisen in connection with temporary or permanent non-use of land for agricultural activity, namely the cultivation of energy crops in these localities, because of growing demand for biomass as a fuel. Farmers are expected to sell energy crops and the fuels they produce, both at home and in the surrounding countries. To choose economically efficient energy crop species to cultivate, the thermochemical parameters of the crop should be used to support decision-making process of farmers. This paper summarizes the results of small-scale laboratory tests of three energy crop species planted in Slovakia – Sida hermaphrodita, Arundo donax, and Miscanthus × giganteus – used for determination of thermal and chemical properties of the energy crop species to evaluate their suitability for energy purposes. The most suitable species for energy purposes was found to be Miscanthus × giganteus with higher heating value of 19.6 MJ/kg, lower heating value of 14.8 MJ/kg (at moisture content of 17%), and ash mass of 2.67% dry mass (d.m.). From a lignin mass and activation energy point of view, the most suitable for energy purposes was Arundo donax, with a lignin mass of 20.5% d.m. and an activation energy of 124.2 KJ/mol.

The density, swelling, and fungal decay of poplar (Populus deltoides) wood treated with pistachio resin (PR) obtained from Pistacia atlantica were investigated. The white-rot fungus Trametes versicolor and the brown-rot fungus Coniophora puteana were used. Methanolic solutions of PR with different concentrations of 1%, 6%, 12%, and 15% were used as the preservative solution. Wood samples were saturated by two different vacuum/pressure (V/P) and dipping methods. The density, volumetric swelling of treated wood, and their mass loss (ML) caused by fungal decay were determined. The density of treated species increased to 15.4% and 5.8% for V/P and dipping methods, respectively, at 15% PR concentration. The volumetric swelling of the treated samples was reduced to 24.5% and 16.8% for V/P and dipping procedure, respectively, at 15% PR concentration. The mass loss of treated samples after exposure to T. versicolor was less than the untreated one (17.4% for V/P and 22.6% for dipping methods at 15% PR concentration). The results showed the better performance of V/P treatment in promotion of wood durability against fungal decay than the dipping method.

Hydration-active steel slag and slag micropowder were used as inorganic fillers with silane coupling agent (KH550) to prepare wheat straw/polyvinyl chloride wood-plastic composites (WPCs) by extrusion molding. A 35-day immersion and a pre-immersion test were carried out to analyze the influence of steel slag and slag micropowder on the physical and mechanical properties of the WPCs under wet conditions. Results showed the following: (1) KH-550 exhibited a good surface modification effect on the activated steel slag and slag micropowder, (2) an increase in the activated steel slag and slag micropowder content could effectively reduce the percent water absorption of the WPCs by 20% to 25% and the expansion by 20% to 24%, respectively, compared with the control group, but had a limited effect on the tensile strength retention, and (3) pre-immersion could effectively induce the synergistic reinforcement effect of the active fillers, resulting in reaching the saturated water absorption within 20 days. The water absorption and tensile strength were respectively 18% to 25% lower and 1.5% to 3% higher than those of the composites without pre-immersion. The results of this study could provide experimental data and theoretical references for the influence of hydration-active inorganic fillers on WPC properties.

This study investigated the feasibility of preparing biodegradable composites, such as food packing materials, from plant leaves as a substitute plastic. Lotus leaves, reed leaves, and basho leaves were treated with hot water and combined with gelatin to form composite samples. The effects on the morphology, thermal properties of leaves, and the mechanical properties and moisture absorption of the composites were studied. The Fourier-transform infrared spectroscopy (FTIR) analysis showed that the amorphous components such as lignin, wax, and pectin were removed after the hot water treatment. The treatment had the most beneficial effect on the reed leaf. The reed/gelatin composites had the best mechanical properties, of which the tensile strength and the flexural strength were 14.0% and 77.1%, respectively, higher than that of the lotus/gelatin composites and 121.5% and 192.5%, respectively, higher than that of the basho/gelatin composites. The morphology of the cross-section of the composites showed that there were numerous holes and gaps in the basho/gelatin composites which induced a high moisture absorption performance.

The basic chemical composition and calorific value of 19 samples of pine sawdust from different forest industries located in five states of the Mexican Republic (Chihuahua, Michoacán, Durango, Oaxaca, and Nuevo León) were determined. The results obtained ranged as follows: total extractives (6.1% to 23.4%), holocellulose (60.1% to 70.4%), lignin (20.5% to 25.8%), ash (0.27% to 0.95%), pH (4.1 to 5.3), and calorific value (20.1 MJ/kg to 21.0 MJ/kg). Except for the ash content, significant statistical differences were found according to the origin of the pine sawdust samples. Based on the results obtained, the sawdust biomass has the potential to obtain densified solid biofuels.

A feruloyl esterase (FAE) gene was isolated from rumen microbial metagenome that consisted of 774 bp encoding 258 amino acid residues. The gene was subcloned into pET 32b vector, expressed in Escherichia. coli, and the enzyme was purified in active form. Homology modeling showed that the FAE contained the catalytic triad composed of Ser80-His236-Asp177, and a classical Gly-X-Ser-X-Gly nucleophile motif commonly found in esterases. Under optimum pH and temperature (pH 7.0, 40 °C), 1 nmole FAE catalyzed the release of 19.75 ± 0.24 µg ferulic acid (FA) from 100 mg corn fiber (CF) in 1 h, which represents 3.5% of FA present in saponified CF. Addition of GH10 endoxylanase (XYN) to 0.5 nmole FAE enhanced the yield by 1.1 fold, equivalent to a 5% increase in FA release. Using CF pretreated with hot water, the synergistic effect of adding XYN resulted in 59.0 ± 0.2 mg FA/100 mg CF (5 nmole XYN, 0.5 nmole FAE), equivalent to a 4-fold increase compared to using the untreated CF substrate under the same reaction conditions.

The wood anatomy of four Atraphaxis taxa that have natural distribution in Turkey—Atraphaxis billardieri Jaub. & Spach, Atraphaxis billardieri subsp. tournefortii (Jaup. & Spach) Lovelius, Atraphaxis spinosa L., and endemic Atraphaxis grandiflora (Willd.)—were compared in this study. The wood samples were sectioned according to standard techniques. Samples were macerated with Schultze’s method. Tangential and radial vessel diameters, intervessel pit diameters, vessel wall thickness, vessel elements length, dimensions of libriform fibres (lengths, widths, cell wall thickness and, lumen diameter), and uniseriate and biseriate ray heights were measured, and the number of vessels per mm2, number of rays per mm, and number of vessels per group were counted. The qualitative features such as growth rings, vessel grouping, presence of helical thickening and storied structure, vestured pits, type of perforation plate, and arrangement of axial parenchyma were determined. These four species of Atraphaxis shrubs differ in some wood characteristics such as growth rings, vessel grouping, vestured pits, height and density of rays, number of vessels per mm2, and the dimensions of the vessel.