Articles

MINERALISATION TREATMENT OF WOOD MATRIX BY HYDRATED LIME

This article concerns the application of lime treatment on wood surfaces. This interaction led to alkaline hydrolysis of the polysaccharide component,which isdirectly linked to physical and mechanical parameters.Whereas the composites utilise the advantageous ecological parameters of the lime binder and wood particle filler, it is necessary to describe this utilisation. Thermal analysis indicated that the transformation of hydrate to carbonate occurs relatively quickly in a thin layer, without causing significant changes in the structure of the wood. This is also confirmed by optical microscopy images. Tests onsmall, defect-free specimens were also conducted to assess the impact on compressive strength parallel to the grain.

Influence of urban agglomeration environment pollution on the concentration of some non-metals in the trunk of Acer platanoides L.

The influence of environmental pollution on the concentration of some non-metals in wood and bark from trunks of Acer platanoides L. obtained from the crossroads of Platynowa and Towarowa Streets and KrakowskiePrzedmieście Street in Warsaw was observed. Samples were collected from approx. 30-year-old and 40 year-old trees from the butt-end and the mid-height of the trunk part as well as from the top part. On the cross-section of the butt-end and the mid-height, the following sections were distinguished: outer, middle and pith adjacent middle wood and of the butt-end part bark was obtained. The discs from the upper part of the trunks were not divided into sections due to their small diameter. The concentrations of chlorine (Cl-), nitrate (NO3-), sulphate (SO4-) and hydro phosphate (HPO42-) anions were determined using HPLC with a conductometric detector. The content of nitrogen (N) was examined with the Kjeldahl method. The influence of the environmental pollution caused by urban agglomeration on the nitrogen content was denoted. Additionally, chlorine anions concentrations in wood and bark were increased.

Research on clustering identification of acoustic emission events in the process of wood crack propagation using PCA

This study presents a methodology for feature extraction and identification of acoustic emission (AE) events during wood crack propagation utilizing Principal component analysis (PCA) and enhanced K-means clustering algorithm. Experimental setups included double cantilever beam (DCB) for mode I crack propagation analysis and three-point bending test for mixed-mode crack propagation assessment. Various AE parameters, such as amplitude, duration, absolute mean value, peak frequency, and frequency centroid, were computed. PCA applied for dimensionality reduction to extract principal components and eliminate redundant information. The optimal number of clusters was determined using a combination of the elbow method and the Davies-Bouldin index to classify damage modes. Results indicate that the principal components contribute to 88.5% and 92% of the variance in the two tests, respectively, yielding three distinct types of AE events in both crack propagation scenarios. Specifically, high-frequency, low-amplitude signals correspond to microcrack initiation; low-frequency, low-amplitude signals signify interface delamination; and high-amplitude, long-duration events indicate mode I opening macroscopic damage (high frequency) and mixed-mode macroscopic failure (low frequency).

VARIABILITY OF THE APPARENT DENSITY IN THE WOOD OF SWIETENIA MACROPHYLLA AND CEDRELA ODORATA IN THE AMAZON REGION OF PERU

This study examines the radial variability of apparent wood density in two tropical commercial species, Swietenia macrophylla (mahogany) and Cedrela odorata (cedar), in the Peruvian Amazon. The hypothesis states that both species will present different radial variation patterns in wood density, with C. odorata showing greater heterogeneity due to its older age and the presence of mineral inclusions. Advanced methods, including X-ray microdensitometry and visual analysis with QGIS, were used to obtain radial density profiles. Results showed that C. odorata exhibited higher variability and a wider density range than S. macrophylla, mainly attributed to age and mineral inclusions affecting density measurements. These differences are important for the timber industry, influencing mechanical properties and material selection. The findings emphasize the significance of density variability for sustainable management and improving timber quality in the Amazon region.

EFECTIVENESS OF SAPPAN WOOD DYE MICROPARTICLES IN THE DYEING OF CANDLENUT AND GMELINA WOOD WITH ALUM AND SODA ASH MORDANTING PRETREATMENT

The aesthetic appearance of wood, especially for handicrafts, is greatly influenced by color. Dyeing is an important method to improve the aesthetics of wood. This research focuses on the effectiveness of wood staining using natural dyes from sappan wood, which has the color-giving compound brazilin. However, natural colorants are often less effective due to their low affinity to wood. Therefore, this study aimed to determine the effectiveness of micro-particles of sappan wood natural dye on candlenut wood and gmelina wood. The pretreatment given during the dyeing process is mordanting using alum and soda ash to improve color absorption and durability. The results showed that mordanting pretreatment with a combination of alum and soda ash (5 g/l : 5 g/l) provided optimal dye penetration depth in both types of wood. FTIR analysis confirmed the interaction between the colorants and the wood components. Candlenut wood showed deeper dye penetration than gmelina wood, which is thought to be due to differences in the anatomical structure of the wood.

Recent Advances in Strengthening and Reinforcing Technologies for Paper Documents: A Comprehensive Review

The reinforcement and strengthening of paper documents have garnered widespread global attention. Delaying the degradation process of paper documents, enhancing their restoration and protection measures hold profound historical and cultural significance for the inheritance of cultural heritage. This study provides a comprehensive review of international advancements in the primary types of strengthening and reinforcement materials as well as the corresponding reaction mechanisms for paper documents. Furthermore, it offers a forward-looking perspective on emerging research trends in the field of reinforcement and preservation for paper documents

POLYETHYLENE GLYCOL/WOOD FLOUR PHASE CHANGE MATERIALS INCORPORATED INTO BIODEGRADABLE WOOD PLASTIC COMPOSITES FOR THERMAL ENERGY STORAGE

To enhance the mechanical and thermal stability of wood-plastic composite phase change materials (WPC PCMs), polyethylene glycol (PEG)/wood flour (WF) PCMs were prepared via solution impregnation. These were added to cellulose, polycaprolactone (PCL), and polylactic acid (PLA)-blended degradable plastics and then compression-molded into WPC PCMs. The materials were characterized using mechanical and thermal tests (SEM, FT-IR, DSC, TG). Research shows that capillary action enables WF to encapsulate PEG, reducing post-phase transition leakage and facilitating heat storage. As PEG content changes, phase change enthalpy and temperature first decrease, then increase, and finally stabilize, with a high latent heat of 33.97 J/g. WPC PCMs exhibit good thermal stability with increasing PEG. When the addition amount of PEG was 30%, compared with the initial decomposition temperature and the maximum decomposition temperature of the material without PEG addition, they increased by 24.4°C and 26.9°C respectively.PEG increases the thermal conductivity of WPC PCMs within a certain range, but the increase is limited. Due to its simple preparation, WPC PCMs have broad application prospects in solar and biomass energy storage

Behavior of Bolted Beam-to-Column Timber Connections using Double Steel Plates

This study aims to investigate the behavior of bolted beam-to-column timber connections with double steel plates. The behavior of the connections, as their strength, initial rotational stiffness, energy dissipation, and ductility ratio, were studied. Test specimens made of red meranti species (Shorea spp.) connected by 5-mm thick steel plates on both sides, and bolted joints of diameters 10 mm and 12 mm were used. Experimental tests of the connections conform to the EN 26891: 1991. The failure mode is splitting of the bolt row path in the column for all connections with the same numbers of bolts in the beam and the column, and splitting of the bolt row path in the beam for all connections with fewer numbers of bolts in the beam than those in the column. Moreover, the results show that the use of combined bolts and double steel plates has an impact in increasing both the ductility ratio and the energy dissipation of the connections

THE ANISOTROPIC VELOCITY MODEL OF INTERNAL ACOUSTIC EMISSION SIGNALS IN ZELKOVA WOOD AND THE INFLUENCE OF HOLES ON THEIR PROPAGATION PROCESS

In this article, an acoustic emission (AE) source was generated through pencil-lead break (PLB). On Zelkova schneideriana specimens featuring central through-holes with diameters ranging from 8 to 16 mm, the time-difference-of-arrival (TDOA) in combination with the least squares fitting approach was utilized to establish an anisotropic model of the AE wave velocity within the wood as it varies with the detection angle. Then, a pulse signal was generated through a signal generator to analyze the influence of the holes on the peak values of AE signals at different angles. The results indicate that when the propagation angle is less than 80°, the AE wave velocity rises rapidly with the increase of the angle and eventually approximates the longitudinal wave velocity along the grain. The AE signal peak emerged in the direction approximately 30° for the specimen without holes. In the presence of holes, as the hole diameter increases, the variation trend of AE peak amplitudes within an angular range of -18° to +18° relative to the hole center becomes progressively smoother, with a concurrent reduction in their mean value. This distinct characteristic can serve as a robust indicator for identifying internal hole defects in wood

ANISOTROPIC PROPAGATION CHARACTERISTICS OF ACOUSTIC EMISSION SIGNALS IN WOOD

This study investigates the propagation characteristics of acoustic emission (AE) signals in Zelkova schneideriana and Pinus sylvestris var. mongolic along different directions, with a focus on amplitude and frequency variations. Sinusoidal signals ranging from 10 to 400 kHz, along with pulsed signals of 1 μs width and 1 s period, were generated using an arbitrary waveform generator to simulate the AE source. Experiments were conducted on 80 mm cubic wood specimens, with the AE source and sensors positioned at the geometric centers of each surface. AE signals were recorded at a sampling rate of 2 MHz. The results indicate that, at the same frequency, the Zelkova schneideriana exhibits higher signal amplitude and energy than the Pinus sylvestris var. mongolic. Frequency response analysis further reveals that wood enhances the propagation of signals below 75 kHz, while significantly attenuating signals above 200 kHz in the transverse direction

SURFACE PROPERTIES OF HYDRO-THERMALLY MODIFIED BEECH WOOD AFTER RADIO-FREQUENCY DISCHARGE PLASMA TREATMENT

Heat treatment is widely used to improve the properties of wood, in particular its color. However, this treatment causes changes in the surface properties of wood, the surface becomes hydrophobic, which can cause serious problems when gluing or coating. In this study, the radio-frequency discharge (RFD) plasma was used to increase the hydrophilicity of the steam-modified beech (Fagus sylvatica L.) wood due to the formation of various polar groups (e.g., hydroxyl, carbonyl, carboxyl, etc.). The increased surface polarity improves the wettability and hydrophilicity due to oxidation reactions. Tensile shear strength properties of lap joints were processed according to EN 205. Plasma-treated samples showed higher strength when compared to plasma-non treated samples after the D4 test according to EN 204

MODELLING OF BIRCH WOOD (BETULA SPP.) SURFACE ROUGHNESS DEPENDING ON LASER PROCESSING PARAMETERS WITH RESPONSE SURFACE METHODOLOGY

In this study, the effect of laser engraving parameters on birch wood surface roughness was investigated with response surface methodology (RSM) and a mathematical model was developed. Laser power (W%), speed (mm/min) and space (mm) were selected as independent variables. Ra, Rq and Rz surface roughness indices were measured as response variables. In the study, 20 experimental conditions were conducted with 3-factor and 3-level experimental designs using central composite design (CCD). Laser engraving power and space were determined as the most effective factors on surface roughness. Regression models were developed for each surface roughness index and the measurements were estimated. In the model created for Ra surface roughness, R² = 97.0% and the average error was found to be 4.9%, for Rq, R² = 96.8% and the average error was found to be 4.5%, for Rz, R² = 96.6% and the average error was found to be 4.0%. It is understood that the surface roughness values will be predicted with high accuracy with the created model

PREPARATION OF ECO-FRIENDLY COMPOSITE PAPER WITH GINKGO LEAF AND BIO-BASED FIBERS

Ginkgo leaf was treated with deep eutectic solvents and then mixed with bio-based fibers, willow catkins or kapok fibers as reinforcing materials to prepare ginkgo leaf composite paper. The effects of the papermaking process conditions and the proportion of ginkgo leaf on the properties of the composite paper were studied. The results showed that the properties of the composite paper were better when the proportion of ginkgo leaf was within the range of 70-90%, with a smooth surface, high strength, and flexibility, which can meet the needs of daily packaging. The higher the proportion of ginkgo leaf, the better the anti-ultraviolet property and the higher the strength. When the proportion of willow catkins or kapok fibers was higher, the water resistance and flexibility were better. Among them, when the proportion of ginkgo leaf was 90%, the ultraviolet protection factor (UPF) could reach 128, showing excellent anti-ultraviolet property. When the proportion of ginkgo leaf was 70%, the water contact angle to composite paper was 144.2°, indicating water resistance

PULPING AND PAPERMAKING POTENTIAL OF ACACIA AULACOCARPA BENTH WOOD IN INDONESIA

In this study, samples from 27-year-old Acacia aulacocarpa grown on a plantation were examined to determine suitable kraft pulping conditions and properties for paper production. The results showed that A. aulacocarpa had a high basic density of 0.65 g/cm3 and a short fiber length of 0.84 mm. The derived values for Runkel, slenderness, and flexibility ratios were 1.02, 53.01, and 0.48, respectively. Five different active alkali concentrations ranging from 14% to 22%, with intervals of 2% were applied for kraft cooking. The percentages of reject, kappa number, and residual active alkali of black liquor were negatively related to the charge applied in pulping runs. Pulping with 18% active alkali content obtained a screened yield of 51.4% at a kappa number of 34.1. The 20% active alkali cook had the highest mechanical properties of the handsheets. The burst and tear indices met the Indonesian National Standard for leaf (hardwood) bleached kraft

EFFECT OF ALKALINE TREATMENT ON MORPHOLOGY AND BIODEGRADATION OF BAGASSE AND MAIZE CELLULOSE

This study investigates the biodegradation behaviour of cellulose extracted from sugarcane bagasse (SCB) and maize using chemical treatments involving sodium hydroxide (NaOH), sodium chlorite, and buffer solutions (NaOH and glacial acetic acid). The extraction process yielded cellulose at 38.00% from SCB and 45.14% from maize, based on the weight of the raw material. The resulting celluloses were characterized using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), confirming their structural and chemical integrity. Biodegradability was evaluated through composting tests, revealing weight losses of 9.08% for SCB cellulose and 29.47% for maize cellulose. The higher degradation rate of maize-derived cellulose suggests enhanced biodegradability

THE EFFECT OF UV ABSORBERS ON THE LIGHTFASTNESS OF DYED VENEERS

To address the problems of fading, surface yellowing and breakage of dyed veneers under prolonged sunlight, this paper uses ash veneers as raw material and new coccine as dye to investigate the effects of bleaching pretreatment, different concentrations (0.5%, 1% and 1.5%) and types of UV absorbers (benzotriazole, TiO2, nano-TiO2) on the color difference value △E of the dyed veneers in the process of aging by natural light and aging by artificial light. The effect of UV absorbers on the color difference △E of dyed veneers during natural light aging and artificial light aging was clarified. The experimental results show that under the natural light condition, the bleached dyed veneer with 0.5% benzotriazole has the lowest △E value, which is about 1.3, and under the artificial UV irradiation condition, the bleached dyed veneer with 1% TiO2 has the smallest △E value, which is about 0.4

STUDY ON THE HYDROTHERMAL TREATMENT OF KILN-DRIED TIMBER OF RED ALDER

This study used red alder (Alnus rubra f. pinnatisecta) and applied humidity control during storage to shorten the health cycle and enhance preservation effects. Orthogonal testing was conducted to assess the impact of humidity control on drying quality and identify optimal conditions. The results showed that: 1) Post-humidity control, most materials exhibited high surface and low core moisture distribution. Surface moisture difference before and after treatment was largest and negatively correlated with moisture increase. Higher temperatures reduced differences at the same treatment duration. 2) Reasonable humidity control significantly improved drying quality: surface moisture remained stable, elastic and mechanical adsorption creep strains decreased, and residual stress was reduced by up to 59.5% after 7 days of humidity and curing compared to room temperature curing. 3) Moisture treatment initially reduced residual stress significantly then rebounded slightly, with stress elimination efficiency generally higher than room temperature. This indicates that humidity control shortens wood storage and curing cycles. 4) Orthogonal test results identified optimal humidity control conditions as 70°C, 85% relative humidity, and 48 h treatment

EFFECT OF SUPERCRITICAL CO2 DEHYDRATION TREATMENT ON THE JUGLANS MANDSHURICA

Conventional kiln drying (CKD) has a long drying period and is easy to cause drying defects. Supercritical CO2 dehydration (SCD) can quickly dehydrate water-saturated wood to above the fiber saturation point without damaging the microstructure and avoiding drying defects. In this study, Juglans mandshurica was treated by SCD to 40% moisture content, then was oven-dried. CKD specimens were used as a control to investigate the effect of SCD treatment on the wood properties of Juglans mandshurica. In the moisture absorption test, the equilibrium moisture content of the SCD and CKD samples was found to be 8.95% and 8.66%, respectively.The final tangential and radial swelling of the SCD samples were 2.5% and 2.03%, respectively, which were 0.1% and 0.24% larger than those of the CKD samples. In the water uptake test, the equilibrium moisture content of SCD and CKD samples was found to be 104.79% and 117.71%, respectively. The final tangential and radial swellings of SCD specimens were 9.38% and 4.6%, which were 2.35% and 1.16% larger than those of CKD specimens. Also, it was confirmed that the extraction content of SCD specimen was reduced, the chemical composition was unchanged, and the open diameter of the pits was about 1.35 μm at 20 MPa/60°C

CHEMICAL CHANGES DURING WOOD CUTTING

Scots pine (Pinus sylvestris) and poplar (Populus euramericana) species were chosen for the experiments.Sawdust was made by a circular saw with a rare tooth spacing for producing bigger particles beside the fine fractions. Particles were separated by a vibration separator with the sieve sizes 1 mm, 0.63mm, 0.315 mm, 0.1 mm and 0.063 mm. Infrared reflectance spectra of the particles were measured to determine the chemical changes generated by the cutting procedure.The experimental results showed that the grinding of wood resulted in bond rupture for all ether bond types appearing in the infrared spectrum. The number of conjugated and unconjugated carbonyl groups in the wood was significantly reduced during the cutting procedure. After bond breaks, oxidation and recombination processes occurred generating compounds similar to the aromatic structure of lignin, which were shown by increases in absorption at 1514, 1271 and 1231 cm-1

Short notes. INFLUENCE OF WOOD ANATOMY ON THE DISTRIBUTION OF GUANIDINE BASED FIRE RETARDANTS IN FIVE FAST GROWING JAPANESE HARDWOODS

This study investigates the influence of wood anatomy on the distribution of fire retardant chemicals in five fast-growing Japanese hardwood species (Melia azedarach, Toona sinensis, Choerospondias axillaris, Alnus japonica, and Liriodendron tulipifera). Given Japan’s increasing demand for sustainable and locally sourced materials, fire retardant treatments are critical for enhancing fire resistance in fast-growing hardwoods used for construction. Using low vacuum scanning electron microscopy (SEM), we examined the distribution of fire retardants in cross-section, radial section, and tangential sections, comparing the effectiveness in ring-porous versus diffuse-porous species. Results revealed that diffuse-porous species (Alnus japonica and Liriodendron tulipifera) retained higher levels of fire retardants with a more even distribution. In contrast, ring-porous species (Melia azedarach, Toona sinensis, Choerospondias axillaris) showed the highest chemical concentration at the edges.