Wood Species Research Articles

Study on the Feasibility of the TG Method for Maximum Water Content Measurement of Waterlogged Archaeological Wood

ABSTRACT Thermogravimetry (TG) is used to measure the change of sample mass versus temperature or time under a program controlling temperature. It is a common thermal analysis tool with a precise built-in balance, and accurate data can be obtained through a small amount of sample at the level of milligrams. The feasibility of the TG method for determining maximum water content (MWC) measurement of waterlogged archaeological wood was studied. Simulated waterlogged wood and waterlogged archaeological wood were used to determine the test condition for the TG method. MWC data obtained through the oven-dry and TG methods with different mass gradients from 0–10 mg to >50 mg were analyzed statistically. Deviation, error bar, and coefficient of variation were evaluated. According to the results, when sample mass is no less than 30 mg, and holding time at 105°C is no less than 40 min, data deviation between these two methods is less than 5%. Effect of sampling depth and presence of inorganic deposits were also investigated. Specimens were taken from an archaeological wood with a sampling depth from 2 to 6 mm, then MWC was measured through the TG method. The results indicate MWC of the samples taken from a depth of 2–4 mm is higher than that taken from a depth of 0–2 mm and is lower than that taken from a depth of 4–6 mm, which is related to inorganic deposits. The presence of deposits was verified through SEM-EDX. MWC of three archaeological wood samples from China and five archaeological wood samples from Italy were measured to verify the effectiveness of the TG method when wood species and degradation degree are different.

Modelling in-ground wood decay using time-series retrievals from the 5th European climate reanalysis (ERA5-Land)

ABSTRACT This article presents models to predict the time until mechanical failure of in-ground wooden test specimens resulting from fungal decay. Historical records of decay ratings were modelled by remotely sensed data from ERA5-Land. In total, 2,570 test specimens of 16 different wood species were exposed at 21 different test sites, representing three continents and climatic conditions from sub-polar to tropical, spanning a period from 1980 until 2022. To obtain specimen decay ratings over their exposure time, inspections were conducted in mostly annual and sometimes bi-annual intervals. For each specimen’s exposure period, a laboratory developed dose–response model was populated using remotely sensed soil moisture and temperature data retrieved from ERA5-Land. Wood specimens were grouped according to natural durability rankings to reduce the variability of in-ground wood decay rate between wood species. Non-linear, sigmoid-shaped models were then constructed to describe wood decay progression as a function of daily accumulated exposure to soil moisture and temperature conditions (dose). Dose, a mechanistic weighting of daily exposure conditions over time, generally performed better than exposure time alone as a predictor of in-ground wood decay progression. The open-access availability of remotely sensed soil-state data in combination with wood specimen data proved promising for in-ground wood decay predictions.

Identification of tropical wood species in paper: a new chemotaxonomic method based on extractives

Abstract The European Deforestation Regulation 2023/1115 (EUDR) prohibits trading of wood and wood products obtained from illegal logging on the EU market. While the identification of solid wood via anatomy, chemistry and genetics has already been established, there is a lack of identification methods for pulp and paper that complement anatomy. This publication presents a newly developed chemotaxonomic method for identifying mixed tropical hardwood (MTH) species in pulp and paper products based on their extractives analyzed with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). The measured data was processed and compared to identify marker substances and was then merged into a fingerprint database for identifying MTH species in paper of unknown composition. As database references, fully bleached kraft pulps were produced from 38 anatomically identified wood samples and then cryo-ball milled and extracted successively with n-hexane and acetone. The results show that the remaining wood extractives generated from bleached pulps are specific enough to find chemical relevant marker substances to detect MTH species. As chemical composition and anatomy are independent characteristics of wood, this paper makes a completely independent method available, which potentially improves the screening for Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) protected species.

Anti-inflammatory, antioxidant, and antitermite valorization of extractable substances from the heartwood of four major species of the Gabonese forest-timber sectors

The aim of this study was to focus on the chemical characterization and the anti-inflammatory, antioxidant, and anti-termite properties of extractable substances from the heartwood of Tieghemella africana, Testulea gabonensis, Staudtia kamerunensis, Entandrophragma utile in Gabon with a view to their valorization. The results of cold maceration extractions revealed that the extractable content varies with wood species and solvent. The high extract contents were obtained with acetone and ethanol, except for S. kamerunensis where the levels of dichloromethane and water extracts were high, respectively, 3.40 and 6.35%. E. useful showed a high content with dichloromethane (4.15%). Phytochemical screening indicated the presence in the acetonic, ethanolic, and water extracts of the wood species several groups of bioactive molecules, such as polyphenols, flavonoids, free quinones, sterols and triterpenes, and saponins. The results of the total phenols assay corroborated those obtained during the phytochemical screening. The results of anti-inflammatory, antioxidant, and anti-termite activities revealed that they vary with wood species, solvent, and concentration in terms of anti-termite activity. The strong anti-inflammatory activities were recorded with the ethanolic, acetonic, and water extracts where the EC50 values of all the essences were the lowest and close to that of our control, diclofenac (555.25 μg/mL). The ethanol extracts of the wood species showed strong activities, particularly those of S. kamerunensis and E. useful where we obtained low EC50 values of 604.13 and 602.38 μg/mL, respectively. The strong antioxidant activities were recorded with the acetonic, ethanolic extracts of S. kamerunensis and E. useful whose respective EC50 values (6.50 and 4.50 μg/mL) for S. kamerunensis and (4.50 and 3.01 μg/mL) for the E. useful. Similarly, the water extract of E. useful whose value is close to that of gallic acid (0.40 μg/mL) our control. The antitermite activity revealed that the acetone and ethanol extracts of the wood species and the water extract of E. useful at 20 mg/mL showed interesting antitermite activities. The strongest activities were recorded with the dichloromethane extracts of the wood species, where the survival rates of the termites were the lowest. Particularly with the dichloromethane extract of E. useful with a survival rate of 30% at 10 mg/mL and 1.70% at 20 mg/mL.

Применение лазерной перфорации для повышения декоративных свойств древесины пихты сибирской (Abies sibirica)

This paper presents research into the possibilities of using laser perforation to enhance the decorative properties of Siberian fir (Abies sibirica) wood. Fir wood is characterized by fairly modest physical and mechanical properties and featureless appearance, which is why it is in low demand. With enhanced decorative properties, fir wood could find its use in the production of finish materials. The literature review reveals that the existing wood dyeing technologies are not really effective for the hard-to-impregnate fir wood. Therefore, laser perforation was used to achieve higher wood impregnation and its controlled coloring to form the texture. The study also explored the features of dyeing laser-perforated fir wood, depending on the set parameters of impregnation and wood structure. To do so, the fir samples (with the size of 165×65×32 mm) were laser perforated to form slots up to 0.2 mm in diameter and 15 mm deep. Then the samples were impregnated in an autoclave. The set parameters were determined in accordance with the two-factor experiment schedule: the pressure standing at 0.2, 0.5 and 0.8 MPa, with the impregnation time of 30, 225 and 480 min. The study showed that when perforated wood is impregnated, the dyeing solution penetrates the laser-cut slots first and mainly spreads along the wood fibers. Depending on the impregnation time and pressure applied, the dye moves from the perforated slots along the wood fibers covering a distance of 10.9 mm to 24.6 mm. The dye does not spread as well across the fibers, only coloring a total width of 1.3 to 1.7 mm both ways from the slot depending on applied pressure and time of impregnation. It was found that, first and foremost, the set parameters affect the size of colored areas along the wood fibers and make little difference to lateral coloring in absolute values. Pressure applied to perforated wood during impregnation was determined to have the biggest impact on the size of colored areas. The study proves it possible to use the developed technology in forming artificial wood textures, including those that imitate valuable wood species. For citation: Eliseev S.G., Ermolin V.N., Duk D.V. Using Laser Perforation to Enhance Decorative Properties of Siberian Fir (Abies sibirica) Wood. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 5, pp. 151–163. (In Russ.). https://doi.org/10.37482/0536-1036-2023-5-151-163

Introduction of Eco-Friendly Finishing Method (YAKISUGI) among the Millennial Generation in Perina Village: Innovation in Unique Furniture Products with High Aesthetic Value

The demand for a diverse range of solid wood products has been steadily increasing. The unique grain patterns inherent to each wood species render solid wood products to possess distinct market segments. Nevertheless, the inherent vulnerabilities of wood as a biomaterial, such as susceptibility to decay, dimensional instability, and low resistance to organisms, necessitate specialized treatment for wood products. One environmentally sustainable treatment methodology, capable of enhancing the aesthetic value of wood, is the yakisugi finishing technique—a method involving the controlled charring of the wood surface. Notably, this technique remains relatively unfamiliar amongst small and medium-sized wood processing enterprises (UMKM) and the millennial generation. Consequently, this engagement initiative assumes significant importance in introducing the yakisugi finishing method to the millennial cohort. The unique visual characteristics of wood, engendered by this technique, hold the potential to serve as a catalyst for innovation in the realm of wooden product development by millennials. The engagement activities primarily encompass instructional modules, comprising theoretical elucidations and practical applications. Participants, affiliated with the youth group 'karang taruna,' have demonstrated appreciable enthusiasm towards the engagement activities that pertain to the yakisugi technique. It is anticipated that novel products will emerge as a result of the application of the yakisugi finishing technique, particularly within the domain of contemporary minimalist furniture products.

Assessment of Forestry Residues Potential for Off-Grid Electrification in The Republic of Benin (West Africa)

This study assessed the potential of forestry residues for off-grid electrification in the Republic of Benin while accounting for the spatial variation of residues potential and their use impact on local biodiversity. We found significant spatial variation of residues potential, with a much higher surplus residues in the north (3,599.05 tons/year) compared to the south (457.79 tons/year). This discrepancy might result from the spatial difference in geographical variables across the two regions. A maximum electricity potential of 100,259,786 kWh can be generated from the theoretical potential of residues which falls short of satisfying the estimated national off-grid electricity demand of 443,916,975 kWh. The research also highlighted the positive influence of wood processing technology and diversity of processed wood species on residues potential. The two variables may be targeted by policymakers to tailor actions for enhancing local transition towards renewable energy. Using scenarios-based projections, our study prompt the conclusion that forestry residues can be used sustainably for off-grid electrification with a minimal impact on biodiversity. Combining the surplus residues from wood processing industries with energy plantations may optimize forestry residues mobilization for off-grid electrification.
 Keywords: wood residues, biomass-electricity, off-grid power, sustainability

SIFAT FISIKA DAN MEKANIKA PAPAN LAMINASI KAYU SENGON DAN JATI PUTIH SEBAGAI SUBTITUSI KAYU SOLID

This study aims to determine the physical and mechanical properties of sengon and white teak laminated boards, the effect of the weight of the coating, the type of wood and their interactions and the strength class of the laminated board. The physical and mechanical properties of sengon and white teak laminated boards are as follows: moisture content of 12.535%, density of 0.402 gram/cm³, thickness expansion of 1.544%, thickness shrinkage of 3.182%, MoE of 19745,840 kgf/cm², MoR of 330.106 kgf/cm². Laur weight did not significantly affect all physical and mechanical properties of sengon and white teak laminated boards except for water content testing. The type of wood had a significant effect on all tests of physical and mechanical properties of sengon and white teak laminated boards except for the MoE test. The interaction of wood species and pumpkin weight had no significant effect on all physical and mechanical properties tests except for water content and MoR tests. Based on the standards of SNI 03-2105-2006 and JAS 234-2007, all tests of physical and mechanical properties of sengon and white teak laminated boards have complied with the standard except for thick shrinkage and MoE tests. Based on the strength class of the laminated board, the laminated board of sengon wood and white teak is included in the strong class III which can be used as indoor construction materials.

Using cellular automata to simulate external heat and mass transfer in the wood drying process

This work involves modeling the external heat and mass transfer in the wood drying chamber. One of the remarkable features of this research is to use cellular automata with variable cell sizes closely related to the geometric parameters of the considered wood materials. This approach allows for modeling and analyzing the changes in the characteristics of wood materials during the hydrothermal treatment process, taking into account their unique geometry. Such modeling provides valuable information about how different shapes and sizes of wood react to various drying conditions. This research has significant implications for industries dependent on wood drying, such as construction and furniture production, as it offers an individual approach to upgrading the drying processes of wood materials with different geometries. The modeling in this work is carried out using wood materials, primarily pine, with a standardized thickness of 25 mm and an initial moisture content of 30 %. The modeling is conducted under conditions of moderate drying, accurately mirroring real-world scenarios. Using pine as the researched material aimed to represent a widely used wood species in the industry, thereby increasing the relevance of the results. The work also explores the influence of various parameters of the wood drying agent. To achieve this, three key factors are systematically varied: temperature, relative humidity, and drying agent velocity. Temperature fluctuations are carried out within a range of ±10 °C. Similarly, relative humidity is adjusted within ±10 % of standard technological parameters. Finally, the drying agent velocity was increased to a maximum of 6 m/s. Thus, the impact of these changes on the moisture content in wood materials is investigated. The results obtained can be applied in an industrial setting. The knowledge gained from the experiments can play a crucial role in improving the wood drying process. In summary, the work investigates the hydrothermal treatment of wood materials, shedding light on the critical role of wood drying agent parameters in controlling moisture content in wood materials. The potential advantages in terms of product quality and overall production efficiency cannot be overstated, and it is expected that this work will be a valuable resource for industries dependent on wood processing.

Assessment of color and contact angle change of weathered wood in relation to wood species and different coating types

Color change was compared through artificial and outdoor weathering tests according to wood species and stain type. In the artificial weathering tests, the color change DE was the highest for the initial 200 hour, and teak solvent-based stain was the most effective in preventing color change. Outdoor weathering tests also showed a rapid color change until the initial 60 days, and the uncoated larch specimens exhibited graying after 120 days. Teak solvent-based stain had the highest preventing color effect, whereas water-based white semi-transparent stain had the highest contact angle. It is difficult to check the color change of wood due to the addition of pigment in teak, as its resistance to moisture is rapidly reduced and its surface protection effect is poor. Water-based white semi-transparent stain prevented color change and maintained a contact angle of 57.1° for up to 150 days, confirming the effect of moisture resistance. This study aimed to provide basic data on weather resistance by wood species and to suggest that the development direction of outdoor exposed wood is a water-based semi-transparent stain.

Effect of NaOH Pretreatment on Permeability and Surface Properties of Three Wood Species

Effect of NaOH Pretreatment on Permeability and Surface Properties of Three Wood Species

Transcriptomics of Temporal- versus Substrate-Specific Wood Decay in the Brown-Rot Fungus Fibroporia radiculosa.

Brown-rot fungi lack many enzymes associated with complete wood degradation, such as lignin-attacking peroxidases, and have developed alternative mechanisms for rapid wood breakdown. To identify the effects of culture conditions and wood substrates on gene expression, we grew Fibroporia radiculosa in submerged cultures containing Wiley milled wood (5 days) and solid wood wafers (30 days), using aspen, pine, and spruce as a substrate. The comparative analysis revealed that wood species had a limited effect on the transcriptome: <3% of genes were differentially expressed between different wood species substrates. The comparison between gene expression during growth on milled wood and wood wafer conditions, however, indicated that the genes encoding plant cell wall-degrading enzymes, such as glycoside hydrolases and peptidases, were activated during growth on wood wafers, confirming previous reports. On the other hand, it was shown for the first time that the genes encoding Fenton chemistry enzymes, such as hydroquinone biosynthesis enzymes and oxidoreductases, were activated during submerged growth on ground wood. This illustrates the diversity of wood-decay reactions encoded in fungi and activated at different stages of this process.

Termo–mekanik yoğunlaştırma işleminin ahşap malzemenin fiziksel özellikleri üzerine etkisi

It can be made into high strength, and valuable products by compacting low density, and low commercial value wood species. In this study, black pine (Pinus nigra) and Uludağ fir (Abies nordmanniana subsp. bornmulleriana) tree species were densified by using Thermo-mechanical (TM) method, which is an environmental modification method, at 140 oC and two different ratios of 25% and 50% (in the radial direction). Compression ratio in air-dry moisture, spring-back ratio after densification, and physical properties of air-dry densities were determined. The obtained data were subjected to statistical analysis in the MSTAT-C program. According to the results, wood type, densification type, and all their interactions were found to be effective on the compression ratio, and spring-back ratio in air dry moisture. The compression ratio in air-dried moisture was lower in Uludağ fir (Uludağ fir: 0.40 gr/cm³, black pine: 0.49 gr/cm³) compared to black pine due to the spring-back effect. While the volumetric recovery (spring-back) rates were 15.44% in Uludağ fir, it was determined as 19.40% in black pine. After the condensation process, the air-dry density value increase was lower in black pine compared to Uludağ fir, and it was determined as 35.94% in Uludağ fir and 34.53% in Black Pine

Lightweight Solid Wood Panels Made of Paulownia Plantation Wood

Light Paulownia seamless-edged glued solid wood panels (SWPs), single-layered and three-layered, were analyzed in this study. Both panel types were calibrated at a thickness of 19 mm, a dimension very often in demand on the SWP market, but produced with other wood species (for example, spruce, pine, larch and fir). The panels were bonded with melamine-urea formaldehyde, polyurethane and polyvinyl acetate resins. The panels were tested for their physical (density) and mechanical (modulus of rupture, modulus of elasticity, compressive shear strength and wood breakage rate) properties. For the single-layered panels, the mechanical and physical properties did not differ significantly and were similar to massive Paulownia wood. For the three-layered panels, the adhesive application of polyurethane influenced positively all SWP properties. Considering the differences in density, these composites failed to achieve the performance of one- and single-layered panels made of spruce. The results of these findings recommend Paulownia SWPs to be used as lightweight and sustainable core materials in sandwich structures for the furniture and packaging industry, sport articles or non-load-bearing constructions.

Tendencies of Termites of the Genera Anacanthotermes Jacobson to Damage the Wooden Parts of Buildings

We have focused our research on determining whether the timbers used as a building material by the population today are resistant or nonresistant to termite damage. The main purpose of this was to learn which types of trees cannot be used as building materials for houses or other structures. In this, we used Salix, Populus, Aleagnus, Ulmus, Pinus, and Betula wood species. We carried out research both in the laboratory and in the field (termite nests and residential buildings). In this case, damage by termites of these pieces of wood placed around termite nests accounts for one year. Salix and Populus wood materials were 86.6±6/50.0±4 percent in laboratory conditions, 93.3±5/90±5 in home, and Pinus and Betula wood materials were 6.6±0.7/0 in laboratory conditions and 13, 3±2/3.3±0.8 percent in home were damage noted. The causes of serious damage to wooden materials by termites are mainly due to the increase of humidity and the growth of fungi. When fungal cultures were isolated from damaged wood and their morphological characteristics were studied, it was found that wood decay fungi belonging to the genera Alternaria and Cladosporium were present. When studying the content of substances difficult to decompose by enzymes and microorganisms in the wood materials, it was found lignin that 20.1±0.3% was present in Salix and 41.2±0.3% in Betula wood. It has been found that in areas with high humidity, wood materials are decomposed by fungi and other microorganisms and the microorganisms multiply faster, As a result, wood more damage by termites. Lignin and some of its compounds prevent the growth of microorganisms. Wood materials made from trees belonging to the genera Pinus and Betula are resistant to termite damage due to their high lignin content.

Modulus of rigidityof commercially important wood species for Mexico: Pinus pseudostrobus, Tabebuia rosea and Quercus scytophylla

Wood is a biological material with applications in engineering and architecture. Its modulus of rigidity is useful for the calculation of beams that work in bending and torsion. The objective of the research was to determine the rigidity moduli and material indices of Pinus pseudostrobus, Tabebuia rosea and Quercus scytophylla. Dynamic torsion tests were performed on 35 small specimens of each species. Linear correlations and their coefficients for determining the modulus of rigidityas a function of density and frequency were calculated. The main results are: The magnitudes of the wood densities of P. pseudostrobus, T. roseaand Q. scytophyllaare located within the interval:587 kg m-3, 735 kg m-3. The coefficient of variation of the frequencies for Q. scytophyllais 50% lower compared to the coefficients of P. pseudostrobusand T. rosea. The coefficient of variation for P. pseudostrobusis 23% greater than that of T. roseaand 146% greater than that of Q. scytophylla. It is concluded that the values reported in this research may be useful if these wood species are used for structural purposes.

Pyrolysis and steam gasification properties of mangroves

The rising atmospheric CO2 emissions from the burning of fossil fuels remains a global concern. Mangrove forests, which are important for global biodiversity, are known for their high carbon fixation capacity. However, the characteristics of the pyrolysis and gasification of mangroves remain unclear. Thus, this study focused on mangroves' basic pyrolysis and steam gasification properties for use as a gasification fuel. Three mangrove species: Rhizophora mucronata, Bruguiera cylindrica, and Avicennia marina, were used as experimental samples. In addition, three species of land wood were used for comparison: Eucalyptus, Japanese cedar, and Japanese cypress. In addition to the raw sample, a demineralized sample was used for each sample to account for the influence of the alkali and alkaline earth metals (AAEMs) on pyrolysis and steam gasification. Thermogravimetric analysis was performed to obtain thermogravimetric curves of mangroves and land wood. A laboratory-scale instrument for pyrolysis and gasification using a batch-type horizontal electric furnace was also used at 800 °C in an inert and steam atmosphere. The char yield of raw mangroves was high and independent of the Klason lignin content, suggesting that AAEMs influence char formation during the initial pyrolysis of the mangroves. The results of pyrolysis and gasification under steam atmosphere showed that the H2 production ratio (Steam/Inert) from mangroves was 2.52–5.33, compared to 1.76–2.35 for land woods, the addition of steam significantly enhanced the steam gasification of mangroves. Mangroves contain relatively large amounts of AAEMs, which indicates their potential as a gasification feedstock.

Chromophores' Contribution to Color Changes of Thermally Modified Tropical Wood Species.

This work examines the effect of thermal modification temperature (180, 200, and 220 °C) in comparison with reference (untreated) samples on selected optical properties of six tropical wood species-Sp. cedar (Cedrala odorata), iroko (Chlorophora excelsa), merbau (Intsia spp.), meranti (Shorea spp.), padouk (Pterocarpus soyauxii), and teak (Tectona grandis). The main goal is to expand the existing knowledge in the field of wood thermal modification by understanding the related degradation mechanisms associated with the formation of chromophoric structures and, above all, to focus on the change in the content of extractive substances. For solid wood, the CIELAB color space parameters (L*, a*, b*, and ΔE*), yellowness (Y), ISO brightness, and UV-Vis diffuse reflectance spectra were obtained. Subsequently, these wood samples were extracted into three individual solvents (acetone, ethanol, and ethanol-toluene). The yields of the extracted compounds, their absorption spectra, and again L*, a*, b*, ΔE*, and Yi parameters were determined. With increasing temperatures, the samples lose brightness and darken, while their total color difference grows (except merbau). The highest yield of extractives (mainly phenolic compounds, glycosides, and dyes) from thermally modified samples was usually obtained using ethanol. New types of extractives (e.g., 2-furaldehyde, lactones, formic acid, some monomer derivatives of phenols, etc.) are already created around a temperature of 180 °C and may undergo condensation reactions at higher temperatures. For padouk, merbau, teak, and partially iroko modified at temperatures of 200 and 220 °C, there was a detected similarity in the intensities of their UV-Vis DR spectra at the wavelength regions corresponding to phenolic aldehydes, unsaturated ketones, quinones, stilbenes, and other conjugated carbonyl structures. Overall, a statistical assessment using PCA sorted the samples into five clusters. Cluster 3 consists of almost all samples modified at 200 and 220 °C, and in the other four, the reference and thermally modified samples at 180 °C were distributed. The yellowness of wood (Y) has a very high dependence (r = 0.972) on its brightness (L*) and the yellowness index of the extractives in acetone Yi(Ac), whose relationship was described by the equation Y = -0.0951 × Y(Ac) + 23.3485.

ANALYSIS OF THE FLOW OF A FIBROUS SUSPENSION IN A GRINDING PLANT IN THE PRODUCTION OF FINE CELLULOSE

Of the various methods for obtaining microcrystalline cellulose (mechanical, chemical, thermomechanical, planting cellulose in powder form from its solutions), the most common is acid hydrolysis of cellulose. The difficulty of obtaining MCC from vegetable raw materials is that, in addition to cellulose, it contains in its composition such compounds as lignin, hemicelluloses, various extractive substances and an insignificant percentage of minerals. When grinding plant fibers in an aqueous medium, both a purely mechanical process of changing the size and shape of fibers and a colloidal chemical process called fiber hydration occurs. Mechanical phenomena are expressed in the shortening of fibers, their longitudinal splitting into fibrils, an increase in the outer surface and the number of free hydroxyl groups on their surface. The term hydration refers to colloidal chemical phenomena that begin with the swelling of hydrophilic plant fibers.&#x0D; The paper considers methods for obtaining microcrystalline cellulose and factors influencing the development of a fibrous suspension isolated from coniferous wood species in a grinding plant with inertial bodies. Multiphysical models of the flow of fibrous suspension in the installation are constructed. A study of the effect of grinding a fibrous suspension on the process of obtaining fine cellulose was carried out. The indicators of the finished product are given. The change in the degree of polymerization of cellulose that has previously passed the grinding stage, with different degrees of grinding according to the Shopper-Rigler, is analyzed. Data on cost reduction and resource savings (acid concentration, temperature and processing time) in the process of obtaining fine cellulose are presented.

The Effect of Bleaching Agents on Color Change in Different Section Shapes in Beech And Fir Woods

Aim of study: It is an investigation of the effects of bleaching processes on the color change in the wood of tree species. Tree species Eastern Beech (Fagus Orientalis Lipsky.) and Eastern Black Sea Fir (Abies Nordmanniana subsp.) were used in the study. Sodium hydroxide-hydrogen peroxide, oxalic acid, peracetic acid diluted 1/3, peracetic acid diluted 1/6 were used as bleaching agents. Trial samples were prepared in accordance with standards and color change measurements were made.&#x0D; Area of study: Surface treatments on wooden materials&#x0D; Material and methods: In the study, two wood species and one varnish type were used; Color changes were tested by applying various bleaches to the wooden material by rubbing method.&#x0D; Main results: As a result of the study, differences were observed in all cross-section shapes in beech wood bleaching measurements with 1/6 diluted peracetic acid, and differences were observed in cross-section shapes in fir wood bleaching measurements. The best bleaching of fir wood was achieved with peracetic acid.&#x0D; Main results: As a result of the study, differences were observed in all cross-section shapes in the beech wood bleaching measurements with 1/6 diluted peracetic acid, and in the cross-section shapes in the fir tree bleaching measurements. The best bleaching of fir wood was achieved with peracetic acid.&#x0D; Highlights: The bleaching process allows the wooden material to easily acquire a homogeneous color. Since the cell arrangements are different in different cross-sectional shapes, the bleaching rates are different from each other. While there is not much difference in the color changes in the wood material when bleached with oxalic acid, the samples are bleached as a result of bleaching with sodium hydroxide-hydrogen peroxide and peracetic acid. Significant changes have occurred in color changes. The reason for this difference is due to the different degrees of corrosion of bleaching agents.