Articles

WOOD RESEARCH Volume 66, Number 5, 2021
Francisco Antonio Rocco Lahr, Eduardo Chahud, Felipe Nascimento Arroyo, André Luis Christoforo, Edson Fernando Castanheira Rodrigues, João Paulo Boff Almeida, Vinicius Borges De Moura Aquino, and Herisson Ferreira dos Santos

Ratio analysis between compression and shearing of 72 Brazilian wood species

The Brazilian standard ABNT NBR 7190 (1997) governs the premises for the wood structure sizing through a table and the simplified method. Thus, this research aims to analyze whether the simplified method shown in the standard matches the resistance values of 72 Brazilian species, separated from class C20 to C60. In the end, it was possible to conclude that the value displayed by the standard between the ratio of shear and compression in the direction parallel to the fibers is half of what actually happens in Brazilian species, showing an urgent review in the standard premises.

WOOD RESEARCH Volume 66, Number 5, 2021
Yueqian Yang, Wei Xu, Xia Liu, and Xiaodong (Alice) Wang

Study on permeability of Cunninghamia Lanceolata based on steam treatment and freeze treatment

In order to improve the permeability of Cunninghamia lanceolata, the weight gain rate of C. lanceolata was taken as index. The effect of time, temperature and water content on the weight gain rate of impregnated wood was analyzed by frozen and steaming treatment. By comparing the weight gain rate under different modification methods, the optimal modification process was determined. The results indicate that the optimum parameters of C. lanceolata were saturated water content (-25°C and 8 h) at this time, the three-day gain rate of silica sol impregnated at normal temperature and pressure was 15.058%. After C. lanceolata is pre-treated by superheated steam, the weight gain rate of C. lanceolata, which in oven-dried specimen (120°C and 3 h) contents was the highest, at this time, the three-day gain rate of silica sol impregnated at normal temperature and pressure was 15.291%. By comparing the results of pre-freezing with the results of superheated steam treatment of C. lanceolata, the latter will increase the permeability of C. lanceolata better. Therefore superheated steam treatment should be chosen as an effective method for the pretreatment.

WOOD RESEARCH Volume 66, Number 5, 2021
Aleš Nečas, JOZEF MARTINKA, PETER RANTUCH, IGOR WACHTER, and TOMÁŠ ŠTEFKO

Impact of the electric cables installation on the ignition parameters of the spruce wood surface

This study is aimed to investigate of an impact of electrical cables installed on Norway spruce (Picea abies (L.) Karst.) wood board surface on main ignition parameters (mainly critical heat flux, ignition temperature, thermal response parameter and thermal inertia). Ignition parameters have been determined by dependence of ignition times (raised to the power of -1, -1/2 and -0.547) on heat flux. Initiation times have been measured for three configurations of spruce wood boards with surface dimensions of 100 x 100 mm ± 1 mm (the first configuration: board without cables on surface, the second configuration: board with three electrical cables on surface – spacing between cables was equal to their diameter and the third configuration: board with five electrical cables – spacing between cables was equal to their diameter) at five heat fluxes (30, 35, 40, 45 and 50 kW·m-2). Obtained results proved that installation of the electrical cables on the spruce wood board surface has a significant impact on the ignition parameters. The critical heat flux (8.5 kW·m-2), apparent thermal inertia 0.20 ± 0.02 kJ2·m-4·K-2·s-1 and ignition temperature 324 ± 105°C of spruce wood board increased up to 18 ± 3 kW·m-2 (critical heat flux), 0.68 ± 0.03 kJ2·m-4·K-2·s-1 (apparent thermal inertia) and 475 ± 27°C (ignition temperature) by the installation of electrical cables on the surface of spruce wood board.

WOOD RESEARCH Volume 66, Number 5, 2021
Jiangtao Shi, Junyi Peng, Chongyang Xia, and Jian Li

A comparison of metabolites in wood-forming tissues from eight commercial timber tree species of Heilongjiang province in China

Four coniferous and four deciduous commercial tree species from Northeastern of China were selected to investigate the differences of metabolites in wood-forming tissues by gas chromatography-mass spectrometry. The results showed that the identified metabolites mainly consisted of neutral sugars, lipids, and organic acids. The mean contents of both arabinofuranose and 1-cyclohexene-1-carboxylic acid were higher in coniferous trees than in deciduous ones. Similarly, the D-fructose and D-glucose content was significantly higher in coniferous trees than deciduous trees, but the total contents of these two sugars was roughly equal among most tree species. The mean content of lactic acid, glycerol and malic acid was lower in coniferous trees than deciduous trees. The malic acid content decreased in later-stages of wood formation than in early-stage for all tree species. The content of L-proline and myo-inositol was greater in later-stage of wood formation than early-stage. The content of octadecanoic acid, D-fructose and D-glucose decreased in later-stage of wood formation for most tree species. All of this suggested that the metabolites in wood-forming tissues showed the significance of species-specific and seasonal dynamic differences among the eight tree species.

WOOD RESEARCH Volume 66, Number 5, 2021
Sarah Augustina, IMAM WAHYUDI, WAYAN DARMAWAN, Jamaludin Malik, Naoki Okano, Taiyo Okada, Kazushige Murayama, Hikaru Kobori, Yoichi Kojima, and Shigehiko Suzuki

Selected properties of compregnated wood using low molecular weight phenol formaldehyde and succinic anhydride

The aim of this study was to investigate the effect of impregnating materials (low molecular weight phenol formaldehyde or LmwPF and succinic anhydride or SA), their concentrations (5 and 10%), and compression ratios (20 and 40% from initial thickness) on improvement of specific gravity (SG) and dimensional stability on nyatoh, sepetir, and pisang putih wood; and then compared them to control and densified wood. The results showed that SG and dimensional stability of compregnated wood were affected by all parameters studied. Higher compression ratio and concentration will result in a greater improvement. In general, SG and dimensional stability of compregnated wood were better than the control. SG of LmwPF- and SA-compregnated wood increased by 10.69‒22.31% and 6.96‒23.09%, respectively. Utilization of LmwPF and SA has significantly reduced the spring-back, but the latter is better. The compression-set recovery after compregnation was 18.34‒33.99%, while after densification was 47.86‒71.49%.

WOOD RESEARCH Volume 66, Number 5, 2021
Mihaela Liu, Jianan Wang, Guanglin Xu, Xin Wei Tu, Xin You Liu, and Zhihui Wu

Efficacy of linseed oil-treated wood to improve hydrophobicity, dimensional stability, and thermostability

In this work, linseed oil was impregnated into the wood at room temperature, under vacuum pressure. The properties of linseed oil-treated wood, including dimensional stability, wood moisture absorption, chemical structure, thermostability, and morphological characteristics, were evaluated. Linseed oil displayed good permeability in Ailanthus wood, with weight gains of 30.95% after impregnation. The swelling coefficients of treated wood in the tangential and radial directions decreased by 25.97 to 33.33%, indicating that impregnation improved the dimensional stability of wood. Moreover, linseed oil treatment significantly modified the wood structure, although the FTIR spectra generally remained unchanged. Observation by scanning electron microscopy showed, that linseed oil impregnated into the wood and occluded pits, thereby prevented moisture absorption. This technique can be used in a variety of wood products, such as buildings, furniture, and landscape architecture.

WOOD RESEARCH Volume 66, Number 5, 2021
Mateusz Kukla, Łukasz Warguła, and Aleksandra Biszczanik

Determining the coefficient of friction of wood-based materals for furniture panels in the aspect of modelling their shredding process

In order to improve the power selection of the drive unit for the shredding machines, the authors determine the values of friction coefficients used in the cutting force models. These values consider the friction between steel and such wood-based materials as chipboard, MDF and OSB. The tests concern laminated and non-laminated external surfaces and surfaces subjected to cutting processes. The value of the coefficient of friction for the tested materials is in the range: for the static coefficient of friction 0.77-0.33, and for the kinetic coefficient of friction 0.68-0.25. The highest values of the static and kinematic coefficient of friction were recorded for MDF (non-laminated external surface) and they were equal respectively: 0.77 and 0.68. In turn, the smallest values of the discussed coefficients were recorded for chipboard (laminated external wood-base surface), which were at the level of 0.33 and 0.25, resp.

WOOD RESEARCH Volume 66, Number 5, 2021
Ruyuan Yang, Jia Wan, Xiaofeng Zhang, and Youfu Sun

Modelling of steel-timber composite beams: Validation of finite element model and parametric study

In this paper, non-linear finite elements models (FEM) of steel-timber composite (STC) beams have been developed and analyzed using ABAQUS software. In the FEM, the loading conditions of STC beams were simulated, and the nonlinear behaviour of the contact interface between the steel and timber components were incorporated adequately into the FEM. For the yield load, the maximum error between the FE results and the experimental results is 14.85%. The maximum average error of the yield deflection is 12.94%. and of the ultimate load is 16.79%. However, the error of key points was less than 17% (within a reasonable range), which proves that the established finite element model, selected material parameters and contact element model can better simulate the bending performance of STC beams. Finally, a parametric study was carried out by using the verified FEM. It is shown that the FEM developed in this study can replicate adequately the load-deflection response, and the development of stress and plasticity of the bending experiment. Through the parameter study, it can be seen that the distribution density and mechanical properties of the connection between the glulam and H-section steel can affect the mechanical behavior of the whole STC beams.

WOOD RESEARCH Volume 66, Number 5, 2021
Aleksandr Vititnev, Yuri Alashkevich, Roman Marchenko, Mikhail Zyryanov, and Aleksandr Mokhirev

Use of logging waste in technologies for deep chemical processing of wood

The study presents theoretical aspects and modern technologies for processing wood biomass, considers the possibility of obtaining wood chips from felling residues of cutting areas, in particular technological chips that meet the GOST 15815: 1983 “Technological chips. Specifications” standard for use as raw materials in the production of fiberboard. Wood fiber obtained from similar in size and quality indicators according to GOST 15815: 1983 technological chips, pre-treated in a defibrator, was subjected to a refining process at a low concentration, in particular using the developed design of the disks of the refiner of fibrillating action while regulating the main parameters of the process. The resulting wood-fiber mass was characterized by an improvement in the fractional composition of fibers, their size and quality indicators. As a result, improving the quality of the wood-fiber mass provides an increase in the physical and mechanical properties of wood-fiber boards under all other equal production conditions, which excludes the use of binding resins, and may indicate the possibilit of effective processing of logging waste.

WOOD RESEARCH Volume 66, Number 5, 2021
Chaobin Zhou, Junjie Ding, Xiaojing Hu, and Wei Gong

Comparative proteomic analysis of the thick-walled ray Formation process of haloxylon ammodendron in the gurbantunggut desert, China

Thick-walled ray cells of Haloxylon ammodendron were first reported by Zhou and Gong in 2017, but their formation mechanism remains unknown. In this study, we performed a proteomic analysis of ray cell wall formation in the xylem. H. ammodendron in Shihezi exhibits a thicker ray cell wall than that in Jinghe. During the process of cell wall biosynthesis in the xylem of H. ammodendron, the nonspecific lipid-transfer protein and beta expansin EXPB2.1 (Mirabilis jalapa) first loosen the cell wall, and this step is followed by extension and expansion. Subsequently, xyloglucan endotransglycosylase/hydrolase 1 cleaves and links the xyloglucan chains. Photosystem I P700 apoprotein A1, reversibly glycosylated polypeptide 1 and GDP-mannose-3′,5′-epimerase are involved in the cellulose, hemicellulose and pectin biosynthesis processes in the cell wall by providing components or energy. Finally, the proteins involved in phenylpropanoid biosynthesis promote lignification of the ray cell wall and complete the biosynthetic process of the cell wall.

WOOD RESEARCH Volume 66, Number 5, 2021
Hongliang Zuo and Jing Di

Experiments and reliability analysis on frame-to-sheathing joints in light wood framed shear walls

To exploit the spruce-pine-fir (SPF) panel and the parallel strand bamboo (PSB) panel used in light wood framed shear wall and investigate the lateral behaviors of frame-to-sheathing joints in light wood framed shear wall with different characteristics, the experimental investigation and reliability analysis were carried out under monotonic load. The test configurations included joints with perpendicular-to-framing-grain load or parallel-to-framing-grain load, with SPF sheathing panel or PSB sheathing panel and with nail or screw. The results suggested that nailed joints with PSB panel occurred ductile failure but other joints occurred brittle failure. Moreover, the ultimate bearing capacity and the elastic stiffness of the joints under perpendicular load were higher than that of the joints under parallel load. The use of PSB panel and screw increased the ultimate bearing capacity of the joints. Furthermore, based on Johansen yield theory and experimental results, the reliability analysis was carried out through first-order reliability methods. The results showed that the SPF-nail joints, the PSB-nail joints, and PSB-screw joints achieved the reliability requirements.

WOOD RESEARCH Volume 66, Number 5, 2021
Emilia Grzegorzewska, Mariana Sedliačiková, and Denis Jelačić

International competitiveness of the furniture manufacturing– lesson from the selected Eu countries

This study aims to compare and evaluate the international competitiveness of the furniture industry in the selected European Union (EU) countries using chosen result-oriented indicators. The results found that countries with the highest levels of international competitiveness of the furniture industry included Poland, Romania and Italy. In contrast, the comparative advantage of Germany, which is the largest furniture exporter in the EU, was not as significant. No comparative advantage in the furniture trade was observed in France and United Kingdom, which is confirmed by the negative values of the Relative Trade Advantage (RTA) index and by unfavorable values of the export specialization index. The results presented in the article expand the existing knowledge in the area of assessing the international competitiveness of the largest furniture exporters.

WOOD RESEARCH Volume 66, Number 5, 2021
Peixing Wei, Jinxiang Chen, Yue Zhang, and Lijun Pu

Wood-based sandwich panels: A review

A sandwich panel with a high ratio of strength to weight is commonly used in aerospace, construction, packaging and other fields. Using a renewable material such as wood to make sandwich panels can achieve a perfect unity of material and structure. In view of the lack of systematic analyses of wood-based sandwich panels, this work reviewed the development of wood-based sandwich panels. Based on the core structure, these panels can be divided into hollow-core structures and solid-core structures. With the emergence of new materials and new technologies, new wood-based sandwich products had been created. However, the current research only focused on the manufacturing, and the related novel design was still lacking. This work put forward a research idea of bionic design based on the integration of structure and function and pointed out the research direction for wood-based sandwich panels.

WOOD RESEARCH Volume 66, Number 5, 2021
Tomasz Ozyhar

Short notes: Application of mineral filler in medium density fiberboard (Mdf) and its effect On material properties as a function of particle size

The addition of inorganic filler material in medium density fiberboard (MDF) and the effect on material properties as a function of particle size was examined. Medium density fiberboard was manufactured in a laboratory scale environment to a target raw density of 750 kgm-3. Wood fibers were replaced by using calcium carbonate at 3 and 10 wt.% using fillers with weighted median particle sizes of d50 = 2.0 μm and d50 = 30 μm, respectively. Urea formaldehyde resin was used as binder in all MDF. The influence of filler addition on the modulus of elasticity, bending and tensile strength, dimensional stability and liquid permeability was investigated. The results demonstrate the effect of filler content and its dependence on particle size. The addition of filler with d50 = 30 μm does not have any influence on material properties up to a filler content of 10 wt.%. Using the finer filler with d50 = 2.0 μm at 10 wt.% filler, the quantity significantly increases the water adsorption and swelling behavior and reduces the strength properties of the MDF.

WOOD RESEARCH Volume 61, Number 6, 2016
Xuexia Zhang, Yan Yu, Zehui Jiang, and Hankun Wang

Influence of thickness and moisture content on the mechanical properties of microfibrillated cellulose (MFC) films

Microfibrillated cellulose (MFC) films with a layered structure and controlled thickness were successfully prepared, from bamboo processing resides as the source material, using ultrasonication followed by simple vacuum filtration. The effects of thickness and moisture content on the mechanical properties of the films were then investigated. It was shown that tensile stress and elongation at break were notably affected by the thickness of the MFC film, where the tensile stress and elongation at break of the film increased from 124 to 179 MPa and 0.9 to 5.5 %, respectively, as film thickness increased from 7.4 to 205.4 μm. However, no notable effect of thickness was observed on the Young’s modulus (~10.8 GPa). It was also found that moisture content has a significant impact on the tensile properties of MFC films, in lowering the Young’s modulus from 12 to 2 GPa and tensile stress from 180 to 90 MPa, and increasing the elongation at break from 4.2 to 17.5 %, as moisture content increased from 3 to 60 %. This is due to the effect of water in softening MFC films, resulting in a reduction in strength and increase in flexibility.

WOOD RESEARCH Volume 61, Number 6, 2016
Lenka Melzerová, Lucie Kucíková, Tomáš Janda, and Michal Šejnoha

Estimation of orthotropic mechanical properties of wood based on non-destructive testing

This paper presents a simple approach for the derivation of effective properties of wood while accounting for its inherent anisotropy. These properties are found by combining the results of structural indentation using the Pilodyn 6J testing device and analytical homogenization in the framework of an inverse approach. This approach provides first a rough estimate of a microfibril angle and subsequently yields the predictions of the effective properties of wood. While applicable to any kind of wood we adopted the proposed methodology to spruce as a typical representative of soft wood. This allows us to exploit the presented results directly in the analysis of glued laminated timber beams made of spruce wood which is a principal goal of the present research.

WOOD RESEARCH Volume 61, Number 6, 2016
Olena Pinchevska, Andriy Spirochkin, JÁN SEDLIAČIK, and Rostislav Oliynyk

Quality assessment of lumber after low temperature drying from the view of stochastic process characteristics

The quality of lumber drying is traditionally evaluated after the process. This paper proposes the algorithm of quality assessment of low-temperature convection lumber drying in accordance with the target values of the average final moisture content and its dispersion in the stack. The stochastic model of the process with random initial and boundary conditions, which allows calculating the dispersion of the final moisture content (MC) was proposed. To describe the kinetics of the wood drying process in the low-temperature chamber in view of the thermodynamic characteristics, 34 processes of drying of oak and pine lumber with the thickness of 30, 40 and 50 mm were made at the wood-processing enterprises in Ukraine. The theoretical equations of lumber low-temperature drying and the values of the coefficients that characterize the influence of material thickness, temperature and moisture fields’ distribution in the material during the drying process were obtained. The check of the proposed models on the uniformity of the average values and dispersion of the current moisture content showed a slight difference between the experimental and calculated values. These models allow predicting the quality of the low-temperature drying on the spread of target moisture content, which enables selection of rational drying schedules.

WOOD RESEARCH Volume 61, Number 6, 2016
Alperen Kaymakci, Nadir Ayrilmis, and Huseyin Akkilic

Utilization of tinder fungus as filler in production of HDPe/wood composite

Selected physical and mechanical properties of high density polyethylene (HDPE) composites filled with various mixtures of wood flour and tinder fungus (Fomes fomentarius) were investigated. For this aim, different mixtures of tinder fungus flour and wood flour (0/40, 10/30, 20/20, and 30/10, and 40/0) (by weight) were compounded with HDPE with a coupling agent (maleic anhydride grafted polyethylene (MAPE) in a twin screw co-rotating extruder. The test specimens were produced by injection moulding machine. The thickness swelling and water absorption of the HDPE/wood composites significantly decreased with increasing content of the tinder fungus flour. The mechanical properties of the composites were negatively affected by increasing amount of tinder fungus flour but there were no significant differences up to 30 wt % tinder fungus content, except for the tensile strength. The optimum physical and mechanical properties for the filled HDPE composites were found to be a 10/30/60/3 formulation of wood flour, tinder fungus, HDPE, and MAPE, respectively.

WOOD RESEARCH Volume 61, Number 6, 2016
ROMAN RÉH and Martin Guoth

Thermoplastic plywood and it’s drawback when moderately heated

GradaTM is new plywood which contains the thermoplastic adhesive. There are so far two material versions 1000 and 2000 which have wide potential in production of wooden products with new perspective of manufacturing. This paper investigates possibilities of including GradaTM material and its versions in skateboard production. Bending strengths at the moderate heat up of this material are presented, specifically at 30, 40°C for both material versions. All increased temperatures are compared to the room temperature (20°C). Mechanical properties that were obtained from the test are modulus of elasticity, modulus of rapture, and stroke strain. The results show the undesirable level of changes present in both versions however version 1000 acts significantly better than 2000.

WOOD RESEARCH Volume 61, Number 6, 2016
Suleyman Ustun, Ergun Baysal, Turkay Turkoglu, Hilmi Toker, Cevdet Sacli, and Huseyin Peker

Surface characteristics of scots pine treated with chemicals containing some copper compounds after weathering

In this study, it was aimed to investigate surface hardness, gloss, and color changes of Scots pine treated with chemicals containing some copper compounds after six months weathering. Adolit KD-5 (AD KD-5), celcure AC-500 (CAC-500), and wolmanit CX-8 (WCX-8) were used as impregnation chemicals containing copper compounds. Scots pine wood specimens were treated with 2 % aqueous solution of chemicals according to ASTM D1413-07e1 (2007) standard. Results showed that while surface hardness and gloss values of untreated Scots pine wood specimens were decreased after weathering, they increased treated Scots pine wood specimens after weathering. The decrease in L* of untreated and treated wood indicates that the specimens became darker after weathering. While weathering caused less green and less yellow for untreated control specimen, it caused less red and less yellow for treated wood. Treated Scots pine wood specimens showed better color stability compared to untreated Scots pine after weathering. In terms of surface hardness, gloss, and color stability values CAC-500 treated Scots pine gave the best results after weathering.