Articles

WOOD RESEARCH Volume 62, Number 3, 2017
Aytekin Onduran, S. Sadiye Yasar, and MUSTAFA ALTUNOK

Investigation of the effects of some modification process to the mechanical performance and deformation of the woodwork

In this study, wood modification (thermo-processing and impregnation) and outdoor conditions of storage (natural aging) the effects on the mechanical performance of industrial woodwork was investigated. For this purpose, naturally grown in Turkey and the commercial value of high Scots pine (Pinus sylvestris L.) and chestnut (Castanea sativa Mill) wood was used. Experimental examples are specifically woodwork has been applied in actual size. Considering the previously conducted research literature only diagonal L-type samples used, not on the actual size samples of woodwork. In addition, there is no study that the combination of the heat-treatment and impregnation. This reveals the original values of this study. For preparing of samples is used the double tenon-mortise corner joint from constructions method and as glue polyurethane based Desmodur VTKA and Polyvinyl acetate based two-component D4. Diagonal woodwork test samples prepared by Thermo S class (185°C temperature with a thermo-vapor process protections) applying. After application of the heat treatment, the test samples impregnated with a solution of 95 % natural pine cone resin and %5 pine tannin by dip method (2 hours). Then, the untreated samples (control), only heat-treated samples and heat treatment + impregnated samples kept for 1 year with outdoor conditions (aging). At the end of the aging, the samples tested according to the principles stated in TS 2472 and TS 7251 EN 107 standard. As result, the performance of woodwork decreased after aging in untreated and heat treatment pieces, the other side after aging – heat treatment, impregnation materials increased the values. The deformation value of woodwork increased after aging most untreated materials, Heat treatment and heat treatment-impregnated reduced aging effectiveness.

WOOD RESEARCH Volume 62, Number 3, 2017
Yo-Jin Song, Soon-Il Hong, Jin-Suk Suh, and Sang-Bum Park

Strength performance evaluation of moment resistance for cylindrical-lvl column using GFRP reinforced wooden pin

In this study, Moment resistance performance of column-beam joints using cylindrical laminated veneer lumber (LVL) column and glulam beam were evaluated. Two types of jointing methods – Type-A, in which the beam is put on the end side of column and Type-B, in which the beam is inserted into column – were applied. As a result of Type A, Moment resistance of the cylindrical-LVL column jointed with drift pins was shown to be 67 % higher than that of the larch log column jointed with drift pins. The larch log column jointed with GFRP Plate reinforced wooden pins was shown to be 14 % higher than that jointed with drift pins. In Type-B joint, the rotational stiffness of two specimens were 139.4 kN•m/rad. (Non-reinforced specimen) and 272.2 kN•m/rad. (reinforced specimen), respectively, and reinforced specimen was 95 % higher than Non-reinforced specimen. Based on this result it was assured that glass fiber reinforcement is able to reinforce the column.

WOOD RESEARCH Volume 62, Number 3, 2017
Ján Svoreň, Ľubomír Javorek, Mária Krajčovičová, Katarína Klobušiaková, Ivan Kubovský, and Richard Kminiak

The effect of the circular saw blade body structure on the concentric distribution of the temperature along the radius during the wood cutting process

The paper presents the experimental results of a research aimed at the distribution of the temperature on thecircular saw blade body. The temperature was measured at four distances from the centre of the circular saw blade body (60 mm, 70 mm, 80 mm, 90 mm) by means of an infrared thermometer. Three circular saw blades with the diameter of 350 mm and a variable adjustment of the body (without slots and coating, with slots and without the coating, with both slots and coating) were used for the longitudinal sawing of the spruce wood (Picea excelsa) with the thickness of h = 25 mm. Feed speed vf = 12 m•min-1 and cutting revolutions n = 4000 min-1 were constant. The measured temperature was in the range from 22°C to 30°C. The highest measured temperatures were recorded on the circular saw blade with the slots and coating.

WOOD RESEARCH Volume 62, Number 3, 2017
Hüseyin Sivrikaya, Ahmet Can, Ibrahim Tümen, and Deniz Aydemir

Weathering performance of wood treated with copper azole and water repellents

Water borne wood preservatives have been widely used for a long time in the protection of wood either in ground contact or above ground. Copper is still major biocide component used today in treatment plant for wood protection despite the environmental concerns over copper-rich preservative systems. On the other hand, water repellents are considered to be potential additives for biocides, resulting in the decreased moisture content, reduced biocide leaching and increased dimensional stabilization. In the present study, copper azole (CA) was used as wood preservatives to the natural weathering for 6, 12 and 24 months respectively. In addition, semitransparent wood stain was used as post treatment with CA, and paraffin and silicon additives were incorporated in to biocide to be water repellent. Paraffin additives reduced the retention values as compared to other formulations. The highest color change and gloss loss were obtained with Scots pine control samples within the six months. CA pretreatment before wood stain was promising by indicating the lowest color change. Color change was reduced by the increasing ratio in paraffin and silicone additives. Combination of CA with wood stain and silicon additive could reduce the copper leaching to some extent.

WOOD RESEARCH Volume 62, Number 3, 2017
Igor Džinčić, Tanja Palija, Mira Mirić-Milosavljević, and Vladislava Mihailović

Size and character of the loads in corner joints within storage furniture

The variations in number and method of applied joints within storage furniture gave idea for this investigation. Importance of joint selection and its geometrical characteristic is clear if we bear in mind that the joints are critical points in the structure, and the rigidity and durability of storage furniture are in direct correlation with the type of the applied joint. Results presented in scientific papers provide little useful information to the engineer for the safe selection of the optimal joint. Number of joints along the connecting line (depth of the box type element) engineers determined empirically. In order to define stress state in the storage furniture, data on size of the load, that the box element has to with stand during its use, should be determined. The aim of this study was to determine the size and character of the loads in corner joints in storage furniture. Based on this data, as well as on the basis of information about the strength of the corner joints it is possible to calculate the required number of appropriate joining elements for each separate case.

WOOD RESEARCH Volume 62, Number 3, 2017
Miroslav Sedlecký and Monika Sarvašová Kvietková

Surface waviness of medium-density fiberboard and edge-glued panel after edge milling

This article deal with investigation of mean arithmetic deviation of the waviness profile (Wa) on edge surface after edge milling of medium-density fiberboard, medium-density fiberboard with single-sided lamination and spruce edge-glued panel. Edge milling afftected feed rate 4, 8, and 11 m.min-1 and cutting speed 20, 30, 40 a 60 m.s-1. There were used for milling 3 types of tungsteen carbide blades with different composition and treatment (HW1, HW2 and HW1 + CrTiN coating). Working results show that the lowest values of waviness were found with a spruce glulam. Considering the machined surface quality the most suitable blade is HW1, then HW1 + CrTiN coating and the worst one is HW2. The lowest measured values of Wa were found with the feed rate of 4 m.min-1 and cutting speed of 60 m.s-1. The increase in cutting speed resulted in the drop in the values of average Wa, while the increase in feed rate had the opposite effect.

WOOD RESEARCH Volume 62, Number 3, 2017
Xu Bin, Yang Zhao Ying, Liu Shuai, and Chao Juan

Comparative identification and analysis amongst suspected gold Phoebe sp. buried wood

Buried wood samples of gold “Phoebe sp.” (Samples #1, #2 and #3) were identified based on their microstructures and on the comparison of their characteristics with relevant specimen types. The result showed all the samples belong to the family Lauraceae. Samples #1 and #3 of the Machilus Nees were identified as Phoebe sheareri and P. zhennan, respectively, they are also known as “Nanmu”. Meanwhile #2 was also referred to as Machilus Nees, but named as “Nanmu with black bark”. Significant differences in anatomical characteristics were determined amongst the three samples; thus, they could not be classified as gold Phoebe sp. Moreover, the practical densities of the samples showed no marked increase relative to the species in literature. Microscopy also exhibited no rare mineral enrichment in the cell lumen or the intercellular space. Results of this study indicated that the three samples do not belong to the category of buried wood or ebony.

WOOD RESEARCH Volume 62, Number 3, 2017
Jarno Föhr, Tapio Ranta, Jemina Suikki, and Hanne Soininen

Manufacturing of torrefied pellets without a binder from different raw wood materials in the pilot plant

This paper concentrated on the production of torrefied without an additional binder from different raw wood materials. The torrefaction and pelletizing was carried out at the Torrec Ltd. pilot plant located in Eastern Finland and its effective capacity was 2,200 tonnes per year. Six different woodchips lots were tested in the pilot runs. The test was to identify whether the pelletizing process requires an additional sealant as a binder. The pelletizing process only exploited condensation water that came about from the torrefaction process. The temperature control range and the holding time were varied, regarding the driving parameters. Finally, quality factors were analysed from torrefied pellets and its raw wood materials after each pilot run. The maximum temperature of the reactor, 260°C, was perhaps too low to manufacture pellets of high energy content. Based on the study, the pelletizing process will not require an additional binder in the future.

WOOD RESEARCH Volume 62, Number 3, 2017
Martin Zachar, Andrea Majlingová, Iveta Mitterová, and IVETA ČABALOVÁ

Influence of an age and damage of the oak wood on its fire risk

The aim of this work is to study the effects of different ages and damage of the oak wood (Quercus petraea Mattusch) in relation to its flash point temperature and ignition temperature, as well as on determination of the ratio of changes in extractives, cellulose and lignin, in the heat loaded samples of 5 – years old oak wood, 160 – years old oak wood, and also 160 – years old oak wood degraded by wood-destroying insects and fungi. The results of the analyses showed that the flash point temperatures were in the range of 357.52°C – 360.63°C.The ignition temperatures were at interval of 398.93°C – 414.92°C. The time to reach the ignition point was at the interval between 344 and 365 seconds. Under the thermal loading of oak wood, there comes to the significant changes, especially in the surface layers. These are, in addition to colour changes, demonstrated the chemical changes of the main components of wood and extractives. Increasing the temperature, there increases also the content of the substances extractable with ethanol and toluene. Increase in their amount is mainly due to the lignin, but partially also due to the polysaccharides decomposition products.

Nezaradené / WOOD RESEARCH Volume 62, Number 3, 2017
Sha Sha Song, Benhua Fei, Xiao Huan Wang, Jun Ni, and Li Hongyao

Effects of different types of housing environments on the physical index and physiological index

The aim of this present study was to promote the quality of living environment, and create a healthy living environment through advocating for low carbon and green buildings. An additional aim is gaining recognition for wood structured housing, thus gaining recognition in customers and consumption to further promote the green ecological and sustainable development of wood structured houses. This work examined the physical environment indexes and physiological indexes of the participants in three different structure types of housing environment with behavioral analysis (CAPTIV) and environmental data (BAPPU) synchronous test system. The results of the MANOVA revealed a significant main effect for the housing environment indexes with temperature, moisture content, noise, illumination, air flow rate and skin temperature, ECG, and respiration of three different structure types (log, glulam, reinforced concrete). In comparison, the influence of the physical environment factors in both the log structure and the glulam structure housing were better than the reinforced concrete structure housing. It indicated that woody housing environment was benefit to the health of habitants. Participants were interested in the log structure and glulam structure housing environment with joy and comfortable feelings. Different proportion of building environment and interior wooden decoration proportion can influence different cognitive and feelings of habitants. Therefore, wooden housing environment is helpful to adjust emotion, relieve work pressure and improve tasty, which would provide people with both physical and mental benefits.

WOOD RESEARCH Volume 62, Number 2, 2017
Simon Eichhorn, Sebastian Erfurt, TAMAS HOFMANN, Stefan Seegmüller, RÓBERT NÉMETH, and František Hapla

Determination of the phenolic extractive content in sweet chestnut (Castanea sativa Mill.) wood

The reason for the excellent natural durability of Sweet chestnut wood can be primarily explained with the extractives incrusted in the wood cell wall. These compounds basically involve tannins, which protect the heartwood against wood decaying microorganisms. Research carried out on the wood of ring-porous broadleaved species revealed that there is a significant radial variation in the concentration of phenolic extractives. The present research focused on the radial distribution of total phenol and ellagitannin content in the heartwood of Sweet chestnut stems, originating from different forest stands. It was also investigated if there was a significant correlation between water supply of the treesand the distribution of phenolic compounds. Total phenol and ellagitannin contents generally increased from juvenile wood towards the sapwood/heartwood boundary, lowest values were determined in sapwood tissues. Respecting water supply it was established that the heartwood of trees growing in a dryer foreststand, contained significantly higher phenolic extractives compared to trees in well water-supplied, fresh forest sites. However, ellagitannin contents didn’t significantly differ between sites. The utilization of the wood of naturally durable European species, including Sweet chestnut, will gain in importance in the future basing on the growing common ecological awareness of the population.

WOOD RESEARCH Volume 62, Number 2, 2017
Xiaoshuai Han, Qinqin Zhang, Ren Li, and Junwen Pu

Grafting organic-inorganic compound modifier onto wood cell walls for enhanced mechanical strength in wood composites

The present study describes the possibility to polymerize functional composite modifier within wood cell walls to obtain functional wood composites (FWCs) with poplar wood acting as the base template. The physical and mechanical properties of the composites, including density, bending strength, compressive strength parallel to grain, surface hardness and water uptake, were evaluated. The FWCs were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), Scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD). According to the results, the functional composite modifiers were successfully in situ deposited into the wood structure by kiln drying. The chemical treatment not only significantly improved the physical and mechanical properties of wood, but also provided the wood with better hydrophobic properties. The abbreviations for substances used in this study are: N-wood (natural wood), MD-wood (methylolurea/DMDHEU copolymerization treated wood), FCM-wood (functional composite modifier treated wood).

WOOD RESEARCH Volume 62, Number 2, 2017
Marcin Klisz, Szymon Jastrzębowski, Tomasz Wojda, Joanna Ukalska, and Andrzej Noskowiak

Variability of Black locust hardness in relation to different measurement direction and location along the stem

The variability of black locust wood hardiness along the stem determines potential uses for this type of material. Characterization of this parameter was conducted based on samples taken from black locust stands in the western of Poland. Study material drawn from each sample tree was divided into three groups (lower stem part, center of the stem and base of live crown) and measuring was performed in three directions (radial, longitudinal and tangential). Due to bimodal distribution of the data, longitudinal direction was analyzed separately from radial and tangential directions. For the longitudinal direction, significance of differences between various stem parts was confirmed (p<0.001), as well as the significance of differences between study sites (p<0.001). For the radial and tangential directions, significance of differences between sites, stem parts and trees was confirmed (p<0.001; p=0.001; p=0.005, respectively). Preferred wood material should come from lower stem part, taking into account the highest hardiness in the longitudinal direction.

WOOD RESEARCH Volume 62, Number 2, 2017
Wei Sun, Xiaokai Mu, Qingchao Sun, and Weiqiang Huang

The impacts analysis of moisture content on mechanical properties of wormwood stem

The disposable chopsticks caused a large amount resources waste of bamboo and wood. Thus, it has a significant resources and environmental benefits using wormwood stem as raw materials to make disposable chopsticks. In this paper, the radial compression and bending performances of wormwood stem were tested with different moisture content, which provide a reference for reasonably design the grinding device of wormwood stem and the feasibility of wormwood stem instead of bamboo chopsticks. The test results show that: the mechanical properties decrease with the increase of moisture content. In the actual grinding process, the moisture content of wormwood stem is controlled about 20%, it can withstand the radial force of 600N and the bending force of 41N, which meet the load requirements of the grinding processing and use. This study provides a theoretical basis for reasonably design grinding device of wormwood stem, producing and storing high quality herbal chopsticks.

WOOD RESEARCH Volume 62, Number 2, 2017
Pavol Halachan, Marian Babiak, Dominik Spišiak, Anatoly N. Chubinsky, Alexander A. Tambi, and Kirill V. Chauzov

Physico-acoustic characteristics of spruce and larche wood

This study deals with non-destructive measurement of wood, i.e. physico-acoustic characteristics (density, dynamic modulus of elasticity, acoustical constant, speed of sound propagation in material and logarithmic dumping decrement). We used two species spruce and larch for measurements. We took wood from two main areas: from Slovakian higher latitudes and from Russia – Siberian areas. Spruce is the main species for the boards of musical instruments and we tried to find another species to replace this one. We measured physico-acoustic properties by two devices: The ultra-sonic tester and device “MEARFA” based on searching correct frequency for each sample. The results show that spruce for top instruments has acoustic constant approx. 12 m4∙kg-1∙s-1 and the “best” value for larch was approx. 10 m4∙kg-1∙s-1. If we compare the methods of measurement of the sound velocity through samples the results for ultrasonic testing are much higher than those provided by resonance-dynamic method. The article also describes differences between physico-acoustical characteristics of sap wood and heart wood, and differences between species.

WOOD RESEARCH Volume 62, Number 2, 2017
Martin Sviták and Daniel Ruman

Tensile-shear strength of layered wood reinforced by carbon materials

This article deals with the influence of selected factors (wood species, used adhesive type, carbon reinforcement) on tensile-shear strength of glued layered wood. Tensile-shear strength was investigated on samples of European beech (Fagus sylvatica L.) and European spruce (Picea abies L.). The laminated wood was modified with carbon polymer or carbon fabric, and the tensile-shear strength values were compared with non-reinforced wood. Polyurethane and epoxide adhesives were used for the experiment. The highest tensile-shear strength values were found on non-reinforced beech wood glued by epoxide adhesive. As far as the tensile-shear strength concerns, each monitored factor as well as their mutual interactions were proven to be statistically significant.

WOOD RESEARCH Volume 62, Number 2, 2017
Hong Yun, Kaifu Li, Chuangshuang Hu, and Dengyun Tu

Adsorption and fixation of soluble fire retardancy in Populus russkii and Cunninghamia lanceolata

Flame retardant treatment is a common method of wood preservation. However, the factory usually uses the same approach to all the wood, but lack of targeted so as to cause waste. This study used poplar and Chinese fir as the species investigated. These species were dipped with boron-nitrogen-phosphorus (B-P) fire retardant. The influences on material loading of processing method, concentration of fire retardant, and drying method were investigated. The contents of B and P were tested by inductively coupled plasma optical emission spectrometry (ICP-OES), after distilled water washing and ultrasonic washing. The results showed that the volume loading increased with the concentration of fire retardant. Freeze-drying can noticeably improve the volume loading, and the impact of the drying method was more notable on poplar than on Chinese fir. The fixation effect of the B and P in poplar was lower by ultrasonic washing than that was by distilled water washing. The fixation effect was opposite in the Chinese fir. Vacuum process was more suitable for the poplar (hardwood), and vacuum-pressure process was
more suitable for the Chinese fir (soft wood).

WOOD RESEARCH Volume 62, Number 2, 2017
Beata Doczekalska, Agata Pawlicka, Krzysztof Kuśmierek, Andrzej Świątkowski, and Monika Bartkowiak

Adsorption of 4-chlorophenol from aqueous solution on activated carbons derived from hornbeam wood

The adsorption of 4-chlorophenol (4-CP) from aqueous solution on activated carbons prepared from hornbeam wood was studied. The adsorption kinetic data were analyzed using pseudo-first order and pseudo-second order models. The adsorption kinetics of 4-CP was better represented by the pseudo-second order equation. The equilibrium adsorption data were described by Langmuir and Freundlich isotherms and the results showed that both models fitted well the 4-CP adsorption; nevertheless, a slightly higher R2 values were observed for the Langmuir model. The effects of solution pH and ionic strength on the adsorption were so investigated. The high 4-CP adsorption capacity (2.71–4.37 mmol.g-1) shows that hornbeam wood is a good precursor for the preparation of activated carbons for the adsorptive removal of organic contaminants.

WOOD RESEARCH Volume 62, Number 2, 2017
Pažitný Andrej, Boháček Štefan, Peter Medo, Balberčák Jozef, Jiří Schwartz, Kuňa Vladimír, and VLADIMÍR IHNÁT

Possibilities of removing condensate from a heat recovery unit utilizable in paper industry

Methods, processes and equipments currently used for heat recovery systems are very diverse in different branches of industry including paper industry. A very important process applied in heat recovery units is condensate removal from the heat recovery units because of optimization of the heat recovery process and extending the working life of heat recovery units. Using of heat recovery units with condensate removal in paper industry fits the innovation trends and means heat energy saving that can be realized by increase of heat recovery efficiency. Heat recovery system with condensate removal should be installed near a drying cover of a paper machine due to reduction of heat loss and pipeline length. Integration of designed spiral heat recovery unit with condensate removal into the existing dryer section of paper machine in a paper mill will lead to decrease of heat consumption and increase heat recovery efficiency up to 91.7 %.

WOOD RESEARCH Volume 62, Number 2, 2017
Miao Ye

Effect of wood modifiers on the physical properties of fast- growing poplar wood

Investigate the wood modifilers effect on the physical properties of fast-growing poplar wood. Wood modifier was applied to impregnation drying operation on fast-growing poplar, and the characteristics of poplar wood before and after modification were observed with X-ray diffractometer (XRD), scanning electron microscope (SEM), energy-dispersive spectrometer and Fourier transform infrared (FTIR) spectrophotometer to analyze the physical properties of the wood. The modification could significantly improve physical properties of the poplar wood. XRD data illustrated that wood modifier could reduce crystallinity of wood from 39.65% to 36.89%. The findings of energy-dispersive spectrometer indicated that nitrogen (N), oxygen (O) and carbon (C) were evenly distributed in the wood. SEM spectrum analyzed the distribution of wood modifier in the wood pores. The FTIR spectra proved that there was cross-linking reaction between the modifier and the internal parts of the wood, and the amount of hydroxyl decreased sharply.