WOOD RESEARCH Volume 63, Number 4, 2018
Hui Ouyang, Zhenling Liu, Lishu Wang, Peng Wanxi, Heping Deng, and Muhammad Aqeel Ashraf

Fungicidal activity and bamboo preservation of Pinus elliottii needles extracts

China is rich in bamboo resources. But there has been a huge gap in timber supply. The most effective solution to eliminate the existing timber supply gap is to carry out the industrialization of bamboo so that the bamboo resources can be fully used. Bamboo is full of nutriments, but it is perishable and difficult to store. Usually bamboo is vulnerable to mildew and insects. Therefore, it is of great significance to research bamboo mold corrosion protection technology for the high-efficient development of bamboo resources. The antifungal activity of different solvent extracting tests were conducted from Pinus elliottii needles (hexane extract(W1), ethyl acetate extract (W2), anhydrous ethanol extract (W3) and water extract (W4)) in white-rot fungus Coriolus versicolor and brown-rot fungi Gloeophyllum trabeum, Polyporus vaporaria Fr. The tests concequence verified that Pinus elliottii needles extracts W1 and W2 have better inhibitory effect on white-rot fungus Coriolus versicolor and brown-rot fungi Gloeophyllum trabeum, Polyporus vaporaria Fr, which indicated that W1 and W2 had possibility to develop as natural fungicide. Further analysis of indoor anti-corrosion of bamboo indicated that W1 and W2 played the best role in bamboo antiseptic effect. The latest research manifested that W1 and W2 have potential to be developed as natural bamboo preservative.

WOOD RESEARCH Volume 63, Number 4, 2018
Ľudmila Tereňová, Katarína Dúbravská, and Andrea Majlingová

Influence of the cross-sectional shape of the log elements to seal the log walls under the thermal loading

The aim of the research was to perform the medium-scale fire tests of two alternate samples of the log wall, using the radiant heat source. The radiant heat source consisted of a ceramic radiation panel with a maximum power of 50.5 kW.m-2 and a maximum temperature of 935°C. The samples varied by their geometric shape and the different design of the groove, which was sealed with glass mineral wool. A better result was achieved by a round wood sample with the circular section, which also resisted to high temperatures in the place of the groove and did not start burning with flame. The sample of the squared log elements started to burn with a flame. Temperature measured in the groove was much higher than in the first case.

WOOD RESEARCH Volume 63, Number 4, 2018
Limin Peng, Meihong Liu, Dong Wang, and Boqi Song

Sound absorption properties of wooden perforated plates

Wooden perforated plates are used to control noise and optimize the indoor sound environment. In the paper, the effects of structure factors on the sound absorption properties, such as the absorption peak, resonant frequencies, and frequency bandwidth, were analyzed using the impedance tube transfer function method and SAS (Data analysis software) significant analysis. Experimental results showed that with the thickness of the medium density fiberboard (MDF) perforated plate increasing from 10 to 20 mm, the resonance absorption frequency shifts to the lower frequency. The depth of hole increased, the absorption peak reinforced. With the pore size increased, the resonance absorption frequency reduced and meanwhile the resonance peak absorption coefficient shrunk. The resonance frequency moves toward the high frequency direction and the sound absorption coefficient decreased when the perforation rate was increased from 3.14% to 7.07%. After increasing the air gap thickness from 25 to 100 mm, the resonance absorption frequency reduced and the sound absorption bandwidth remained relatively constant as the acoustic impedance of the MDF perforated plate did not vary in spite of the variation in the air gap thickness. But the absorption coefficient decreased. This paper may provide a certain theoretical basis for wooden perforated plate design and research.

WOOD RESEARCH Volume 63, Number 4, 2018
Ilyas Deveci, Cevdet Sacli, Turkay Turkoglu, Ergun Baysal, Hilmi Toker, and Huseyin Peker

Effect of SiO2 and Al2O3 nanoparticles treatment on thermal behavior of oriental beech wood

In this study, investigation of the thermal properties of Oriental beech (Fagus orientalis L.) wood samples treated with 1.50 and 3.00% aqueous solutions of SiO2 and Al2O3 nanoparticles were performed by using thermogravimetric analysis (TGA), differential-thermogravimetric (DTG), and differential-thermal analysis (DTA) under argon atmosphere. Thermal degradation of SiO2 and Al2O3 nanoparticles treated Oriental beech wood could be separated in three district regions. These regions could be called as drying, pyrolysis, and charring. Our results showed that Al2O3 and SiO2 nanoparticle treatment increased residual char yield of Oriental beech wood samples. The highest residual char yield was obtained for wood samples treated with 3.00% Al2O3 nanoparticles. Moreover, higher concentration levels resulted in lower Tmax values, higher Ti values and higher char yield of Oriental beech wood.

WOOD RESEARCH Volume 63, Number 4, 2018
Zuzana Kamenická, Jaroslav Sandanus, Lukáš Blesák, Kamila Cábová, and František Wald

Methods for determining the charring rate of timber and their mutual comparison

There are simplified and advanced design methods for the determination of the mechanical resistance of timber structures in fire. The simplified methods have some limitations and in case it is not possible to use the simplified methods, it is necessary to use the advanced ones. These advanced design methods can be analytical or numerical. This contribution deals with the determination of the one-dimensional charring rate depending on time by advanced calculations, focusing on the influence of different input parameters, with the results of an experiment being presented for comparison. The aim of this paper is to show that despite the suitability and conservativeness of the method according to Eurocode 5, there are various cases (different moisture, wood species etc.) when it is necessary to perform numerical or analytical analyses without the possibility to apply standard input parameters. Therefore, this contribution compares individual methods for finding of the most appropriate one.

WOOD RESEARCH Volume 63, Number 4, 2018
Ming Chen, Xiangmin Li, and Jianhua Lyu

Influence of dowel diameter and curing time on strength of double dowel joint

The tensile and bending strength of double wood dowels in medium density fiberboard components was tested by using experimental method which was conducted to define the influence of dowel diameter and curing time on tensile and bending strength of T-shaped and L-shaped double wood joints. The results showed that the dowel diameter and curing time have a great effect on the tensile and bending strength of T-shaped and L-shaped double wood joints. The obtained optimum technical parameters were respectively as follow: dowel diameter was 10.00 mm for tensile strength of T-shaped joints, dowel diameter was 10.00 mm for bending strength of T-shaped and L-shaped joints, and curing time was 168 h for bending strength of T-shaped and L-shaped joints. The relational expression between dowel diameter R and the tensile strength P was obtained in P= 159.7R+11.05, the relational expressions between dowel diameter R and the bending strength P were obtained in P= 30.7R-58.21 and P= 25.48R-41.04 for T-shaped and L-shaped double wood joints, respectively. Moreover, the relational expression between curing time T and the bending strength P in the P= -0.003T2+0.683T+164.1 and P= -0.003T2+0.746T+132.0 for T-shaped and L-shaped double wood joints, respectively.

WOOD RESEARCH Volume 63, Number 4, 2018
Stanislav Doubek, Vlastimil Borůvka, Aleš Zeidler, and Ladislav Reinprecht

Effect of the passive chemical modification of wood with silicon dioxide (silica) on its properties and inhibition of moulds

This work investigates how wood modification with silicon dioxide affects its selected physical and mechanical properties and resistance to moulds. Silicon mineralization can improve some of the technical properties of wood and extend the service-life of wooden structures. Silicon, which is contained in inorganic and organic-inorganic substances that are used for artificial wood mineralization or is the main component at natural wood mineralization, was used in the form of colloidal silicon dioxide and its various concentrations for pressure impregnation of beech (Fagus sylvatica) and Silver fir (Abies alba) wood samples. Following, physical, mechanical and biological properties of such modified woodswere tested together with waterlogged fir wood stored in water over a long period. Silicon-dioxide did not significantly improve properties of beech and fir woods, probably due to the hypothesis, that none covalent bonds between the silicon and the OH- groups of cellulose, hemicelluloses or lignin could be created in the cell-walls of the silicon-modified woods.

WOOD RESEARCH Volume 63, Number 4, 2018
Bin Na, Haiqing Wang, Tao Ding, and Xiaoling Lu

Study on factors affecting the sound absorption property of magnesia- bonded wood-wool panel

Magnesia-bonded Wood-Wool Panel is a kind of environmentally friendly inorganic material with wood-wool as matrix materials, and magnesium oxychloride cement (MOC) as binder which is also a kind of porous material with nice sound absorption property. In this study, through single factor experiments, it was found that The thickness of the panel, molar ratio of MgO/MgCl2/H2O, wood-wool length influenced material sound absorption performance of the panel significantly. The thickness of the panel was the most significant factor affecting the panell’s sound absoption property, while the effects of density of the panel and weight ratio of magnesia to wood were not significant. The optimal factors were obtained through orthogonal experiments: Thickness of the panel 25 mm, molar ratio of MgO to MgCl2 to H2O 5: 1: 10, density of the panel 0.65 g.cm-3, weight ratio of magnesia to wood 1.25, wood-wool length 200 mm.

WOOD RESEARCH Volume 63, Number 4, 2018
Partson Tinarwo, Temesgen Zewotir, and Delia North

Pre-hydrolysis pulping process optimization with multiple response surface modelling

Three properties of dissolving pulp namely lignin, viscosity and the α-cellulose were investigated. A laboratory experiment for the dissolving wood pulping process was conducted on nine Eucalyptus genotypes: Edunnii, Esmithii, Egrandis, Macarthurii, Emearnsii, Enitens, GCG438, GUA380 and GUW962. Repeated measurements were taken at each of the six processing stages for the changes in lignin, viscosity and the α-cellulose. A response surface approach was used to select the best genotype for each property and further application of desirability analysis to identify the genotype that simultaneously gives the best results for the three properties. The predictive models and associated statistical tests proved that all the nine genotypes were capable of producing the optimal results (>95.55% α-cellulose) although a few were at the thresholds of the feasible region. The optimisation process also revealed that the genotype Emearnsii possesses the most desirable properties for the α-96 cellulose product output and Enitens consistently produces results within the desired range. The use of simultaneous desirability functions indicated that the overall product quality characteristics for lignin, viscosity and the α-cellulose can be improved by steadily excluding the most resistant genotypes to lignin reduction, especially Edunnii and Esmithii.

WOOD RESEARCH Volume 63, Number 4, 2018
Mária Fišerová, Elena Opálená, Juraj Gigac, and Monika Stankovská

Oxidative and reductive bleaching of deinked pulp

Deinked pulps for hygienic paper production were bleached with hydrogen peroxide and sodium dithionite in single and two-stage bleaching. The brightness gain of high brightness deinked pulp in the peroxide stage was 5.7% ISO and of low brightness 4.4% ISO. In sodium dithionite stage, the brightness gain of high brightness deinked pulp was 4.0% ISO and of low brightness deinked pulp 3.8% ISO. The two-stage oxidative-reductive bleaching sequence resulted in an increase of brightness by 9.7% ISO for high brightness deinked pulp and by 9.1% ISO for low brightness deinked pulp. Brightness gain in the two-stage reductive-oxidative bleaching sequence was 6.7% ISO for high brightness deinked pulp and 5.6% ISO for low brightness deinked pulp. The coordinate b* value and yellowness of deinked pulps decreased in sodium dithionite bleaching stage more than in hydrogen peroxide stage. The two-stage oxidative-reductive bleaching sequence is more preferred than reductive-oxidative sequence regardless of the fibre composition. The tensile index and the tensile energy absorption index of deinked pulps slightly decreased after single-stage and two-stage bleaching sequences, their reduction in the peroxide stage was greater than in the dithionite stage. The fibre strength and fibre length characteristics of deinked pulps decreased after bleaching, while fibre bonding ability increased. The water absorption and bulk softness increased after bleaching, the increase was higher after peroxide stage than dithionite stage.

WOOD RESEARCH Volume 63, Number 4, 2018
Wang Yanming, Chen Zhongjia, Yuan Xiangyue, and Yu Guosheng

Influence of die temperature and moisture content on the densification of bamboo powder using die heating method

Residues of agriculture and forestry are usually exploited as feedstock within pellet production for energy producing applications. Some variables such as moisture content and die temperature strongly influence this process. Bamboo powder was used as the experimental material to produce high quality pellet fuel in this paper. A series of experiments involving pellet production were conducted in different die temperatures and at different moisture contents by a newly-developed pellet extruder using a die heating production method. Unit density and densification pressure were tested with four levels of moisture contents (5, 10, 15 and 20%) at five levels of temperatures (40, 80, 120, 160 and 200°C). The surface quality of the pellets was investigated 6 months after the pellets had been produced. The optimum moisture content is around 10% and a suitable die temperature is 160°C to 200°C when producing bamboo pellets.

WOOD RESEARCH Volume 63, Number 4, 2018
Mohammad Mehdi Ramezanpoor Maraghi, Asghar Tabei, and Mostafa Madanipoor

Effect of board density, resin percentage and pressing temprature on particleboard properties made from mixing of poplar wood slab, citrus branches and twigs of beech

In this study, construction conditions of homogenous particleboard manufactured from mixing of poplar wood (Populus alba) slab, citrus branches and beech (Fagus orientalis) twigs have been investigated. The density of particleboard at three levels of 0.65, 0.7 and 0.75 g.cm-3, the amounts of resin at two levels of 9 and 11% and the amounts of pressing temperature at two levels of 160 and 170° C were considered. Increasing the density from 0.65 to 0.75 led to an increase in MOR, MOE and IB. By increasing the density, water absorption of particleboard decreased but its thickness swelling increased. By increasing the resin percentage the mechanical properties of particleboard improved, although this improvement was not statistically significant. Furthermore, by increasing the resin percentage the dimensional stability of particleboard improved partially. Not only did increasing the pressing temperature have any significant effect on the improving of mechanical properties of the particleboard, but also it has even led to a decrease in IB. Increasing the pressing temperature reduced the water absorption of particleboard in the short term (2 hours) while this increase led to a further increase in the thickness swelling of particleboard.

WOOD RESEARCH Volume 63, Number 4, 2018
Miroslav Sedlecký, Monika Sarvašová Kvietková, Richard Kminiak, and Lukáš Kaplan

Medium-density f iberboard and edge-glued panel after edge milling – surface waviness after machining with different parameters measured by contact and contactless method

This article deals with the quality of the milled surface of board edges. The quality is evaluated using the Wa (mean arithmetic deviation of the surface waviness). The Wa was measured by two methods (contact and contactless). Form Talysurf 50 Intra was used for the contact method, and the LEXT 3D measuring laser microscope OLS4100 was used for the contactless method. The variable factors whose effect on the resulting waviness was determined were the machined material, milling cutters, cutting speed and feed rate. The boards used were medium-density fiberboard, medium-density fiberboard with single-sided lamination and spruce edge-glued panel. Three different cutters were used for the milling, all of which were made of sintered carbide, and one of them was coated (CrTiN). The cutting speeds were 20, 30, 40 and 60 m.s-1, and the feed rates were 4, 8 and 11 m.min-1. All the above-mentioned factors as well as their mutual interaction had an effect on the waviness. There was no significant difference between the two methods for determining the waviness. In terms of waviness, both methods are interchangeable.

WOOD RESEARCH Volume 63, Number 4, 2018
Chenah May and Amrani Moussa

Chemical and structural analysis of lignocellulosic biomass of Ampelodesmos mauritanicus (diss) and Stipa tenacissima

Chemical composition, anatomical characteristics and cell wall structure of Ampelodesmos mauritanicus (Diss) and Stipa tenacissima (Esparto grass) fibers were analyzed. The results reveal the % (W/W) holocellulose content of Diss and Esparto grass was found to be 54.39 % and 51.8 %, respectively. Esparto grass had the greatest % (W/W) lignin content of 32.2 % while Diss had the last lignin content of 24.95 %. Estimation of %( W/W) extractives contents in Diss and Esparto-grass were observed to be 12.03 % and 13.5 % in that order. According to XRD data, Diss showed, as expected, a lower crystallinity index (CI) 52.5 % when compared to Esparto grass samples 55.2 %. The results of the thermal decomposition of natural fibers are shifted to higher temperatures with increasing the cellulose crystallinity. Based on the results of the chemical composition of Diss and Esparto grass, it was confirmed that straw is rich in cellulosic fibers and, therefore, a valuable raw material for the paper and manufacture industry.

WOOD RESEARCH Volume 63, Number 4, 2018
Ekrem Durmaz, Saim Ates, Laboni Ahsan, Zhibin He, and Yonghao Ni

Characterization of microfibrillarcellulose (MFC) obtained from corn stalk, sunflower stalk, reed and sesame husk

Microfibrillar cellulose (MFC) samples from different agricultural resources and their wastes were characterized and compared in this study. MFCs were prepared from corn stalk, sunflower stalk, reed and sesame husk by two different methods. Hydrochloric acid (HCl) was used in Method 1, while formic acid (CH2O2) and sulphuric acid (H2SO4) were used in Method 2. SEM, FTIR, XRD and TGA analyses were conducted to determine the morphological, physical and thermal properties of the MFCs. The widths of the MFCs varied between 2.35 μm – 7.96 μm depending on the treatment methods and the raw materials. The crystallinity index of the lignocellulose increased after the chemical treatment, and the highest crystallinity index was found to be 82.0% for the sesame husk treated by Method 2. FTIR results indicate the presence of cellulose (~1640 cm-1), hemicellulose (1740 cm-1), lignin (1510 cm-1) and the other components in the MFCs. The TGA results show that the decomposition temperatures for the treated samples were higher than those for the untreated samples, indicating that the chemical treatments increased the thermal stability of the MFCs. As a consequence, it was seen that agricultural resources and their wastes can be an effective raw material in production of MFCs.

WOOD RESEARCH Volume 63, Number 4, 2018
Qian Wan, Ge Ge Wang, Ya Chi Zhang, Sha Sha Song, Ben Hua Fei, and Xiao He Li

Cognitve processing torword traditional and new chinese style furniture evidence from eye-tracking technology

Eye-tracking technology was shown to have the ability to indicate human’s cognitive preferences toward objects. Using eye-tracking technology to study the cognitive preferences on different Chinese furniture style may have the potential to promote the furniture design from a novel perspective. Experiment was designed to test the differences of eye movement index (total fixation time, average fixation counts and average pupil diameter) within variables of gender, major and furniture styles. Participants were asked to observe two sets of different styles of Chinese furniture pictures on computer screen. Significant differences of total fixation time and average fixation counts were found between different furniture styles (p<0.01), gender (p<0.001), but not in major (p>0.05). Significant difference was also found in average pupil diameter in different furniture styles (p<0.01) and gender (p<0.01).Subjects’ fixation time stayed longer on new Chinese style furniture pictures than traditional furniture pictures. The results indicated that compared to traditional Chinese style furniture, people tend to take more interest in the new Chinese style furniture. Gender as a factor had a significant influence on the cognitive processing towards the viewing of pictures of the Chinese style furniture. Meanwhile, subjects paid more attention to the decorative details on the furniture, implying appropriate design and decoration may improve people’s interest to the furniture.