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Showing papers in "European Journal of Wood and Wood Products in 2002"


Journal ArticleDOI
TL;DR: In this paper, the authors used bending test data from the ASTM 2017 standard to show that such treatment may create a 10 to 50% reduction in MOR and deflection, which will limit the use of such wood for structural purposes.
Abstract: and 46% for P. placenta. About 56% and 54% weight loss were obtained for southern pine control exposed to G. trabeum and P. placenta, respectively. The weight loss of the water and acetone extracted heat-treated sample exposed to P. placenta was 49.7% and 53.9%, respectively. Only about 11% and 14.8% weight loss was obtained for water and acetone extracted samples exposed to G. trabeum. The moisture content of the tested samples was about 70 ± 10% for the un-heated controls and 50 ± 10% for heat-treated samples. This treatment may modify the durability from non-resistant to moderate/resistant species depending on the fungus species as defined in the ASTM 2017 standard. The data from the bending test indicate that such treatment may create a 10 to 50% reduction in MOR and deflection, which will limit the use of such wood for structural purposes.

547 citations


Journal ArticleDOI
TL;DR: In this article, a number of approaches that could be used as a selection tool in tree breeding for better product performance of radiata lumber were explored. But the results do not offer definitive solutions but explores a good correlation between acoustic and static measurements of modulus of elasticity.
Abstract: clones with high modulus of elasticity (MOE). Various ways of measuring MOE are examined: traditional static bending, axial compression of bolts, existing sonic methods, as well as a tool specifically configured for resonance on short bolts. Wood characteristics and microfibril angle are measured on discs taken from each tree. Results show a good correlation between acoustic and static measurements of modulus of elasticity. Moreover, the selected seven radiata clones differ in stiffness by a factor of two, and much of this variation seems to relate to differences in microfibril angle. The results validate the assumption that there is potential to improve wood stiffness of radiata pine genetically. This work does not offer definitive solutions but explores a number of approaches that could be utilised as a selection tool in tree breeding for better product performance of radiata lumber. Here, development of methods based on acoustics is shown to assist in the necessary mass screening of clones for stiffness properties.

125 citations


Journal ArticleDOI
TL;DR: The color homogeneity was less for birch sapwood than for pine and spruce, and the homogeneity decreased with increasing treatment temperature as mentioned in this paper, indicating that pine sapwood became much redder and darker compared with spruce.
Abstract: Clearwood of Scots pine, Norway spruce, and birch was subjected to heat treatment while capillary water was kept in the wood. The treatments were performed on initially green wood from 65°C to 95°C from 0 to 6 days, followed by drying at 35°C for 2 days. Color measurements, CIEL * C * h color space, were made on dry planed samples using a photoelectric colorimeter. Treatment time was more important than temperature for birch sapwood regarding the color responses, while time and temperature were of similar importance for pine and spruce. Birch sapwood became much redder and darker compared with pine and spruce. The darkening accelerated generally when treatment temperature exceeded approximately 80°C. Pine and spruce showed generally similar color responses, untreated and treated, except for pine heartwood untreated, which showed a more saturated color. Pine treated at 65°C and 80°C showed red-yellow shift and yellow-red shift for sap- and heartwood respectively, as time elapsed. The color homogeneity was less for birch sapwood than for pine and spruce, and the homogeneity was generally indicated to decrease with increasing treatment temperature.

104 citations


Journal ArticleDOI
TL;DR: In this paper, a brown rot fungus (Coniophora puteana) was selected in order to determine and compare the effectiveness (threshold value) of the linear chain anhydrides.
Abstract: Schneid) sapwood. A brown rot fungus [Coniophora puteana (Schum.:Fr)] was selected in order to determine and compare the effectiveness (threshold value) of the linear chain anhydrides. The work described in this paper has demonstrated that chemically modified Corsican pine sapwood afforded substantial bioprotection against Coniophora puteana. With all anhydrides studied, a weight gain of 18% following reaction ensured complete protection. The results indicate that degree of cell wall bulking by the bonded adduct, rather than extent of hydroxyl substitution is the primary factor controlling decay resistance.

104 citations


Journal ArticleDOI
TL;DR: In this paper, a method to evaluate the influence of wood polymers and extractives on the color of wood subjected to hydrothermal treatment was proposed, and the technique used was extraction and color measurement.
Abstract: A method to evaluate the influence of wood polymers and extractives on the color of wood subjected to hydrothermal treatment was proposed. As such, the technique used was extraction and color measu ...

102 citations


Journal ArticleDOI
TL;DR: In this article, a round robin test was carried out on nine different locations in Europe to evaluate a new test method for accelerated natural weathering of exterior wood coatings and European standardization and the results showed that the correlation between the calculated climatic index and weathering results appeared to be very poor.
Abstract: To evaluate a new test method for accelerated natural weathering of exterior wood coatings and European standardization a round robin test was carried out on nine different locations in Europe. Part of the evaluation consisted of investigating the relationship between the weathering results and the meteorological conditions on each site. The aim is to develop a climatic index, reflecting differences in severity of climate in different areas within Europe with respect to the weathering of coatings on wood. Preferably the relationship should be uniformly applicable to all coatings systems, making it possible to transfer test results from one location to another using this climatic index, in order to reduce the need for natural weathering tests on different sites. From the preceding literature study, in which the climate elements relevant for ageing effects of exterior wood coatings have been characterised, it was concluded that a climate index relevant to this purpose should be composed of global irradiation, total precipitation and number of days with more than 0.1 mm precipitation. For all tested coating systems together the correlation between the calculated climatic index and weathering results appeared to be very poor. No unambiguous relation could be found, which was valid for all systems. Thus, transferring weathering results from one location to another, independent of the coating system, does not seem possible on the basis of these results. When seperating the results obtained from the standardized coating 'Internal Comparison Product (ICP)', the relationship was considerably better. Transferring results by means of the ICP could therefore constitute a more suitable approach. Of the climate factors involved, only global irradiation showed reasonable correlation to the weathering results. Including the data on precipitation hardly improved the model.

54 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used NIR spectroscopy for on-line assessment of veneer stiffness prior to layup of plywood or LVL panels, and the results showed the potential for using NIR analysis for online assessment of Veneer stiffness.
Abstract: D. Don) veneers. Spectral data obtained from 1.2×2.4 m veneer sheets was corellated against stiffness data obtained from 6-ply mini-LVL panels prepared from the sheet. This paper describes the method used to prepare the mini-LVL test pieces and the results of multivariate regression of NIR spectra with the test piece stiffness. The results show the potential for using NIR spectroscopy for on-line assessment of veneer stiffness prior to layup of plywood or LVL panels. Selection of high stiffness veneers for layup would enable engineered panels of high uniform stiffness to be produced.

51 citations


Journal ArticleDOI
TL;DR: In this article, the effect of ground pulp on physicomechanical responses of fiberboard was evaluated and the results showed that the changes are due to the segregation of packages of fibers and not to the cut of the fibers.
Abstract: was thermomechanically pretreated and used to produce fiberboard with no synthetic binders. The lignocellulosic material was steam exploded using an aqueous vapor process in a batch reactor. Part of the resultant pulp was ground to pass through a 4-mm sieve. The effect of the grinding on the physicomechanical responses of the fiberboard was evaluated. ANOVA methodology was used. The boards obtained with the ground pulp were of better quality that those obtained with the non-ground pulp. The milling process considerably improved the internal bond strength and diminished the density of the board. The other measured properties (MOE, MOR, WA and TS) were not significantly affected by the process. Scanning electron micrographs show that the changes are due to the segregation of packages of fibers and not to the cut of the fibers. This segregation increases the inter-fiber bonding area.

50 citations


Journal ArticleDOI
TL;DR: The study indicated that an antibacterial effect of wood, especially for pine, is caused by the hygroscopic properties of wood and the wood extractives.
Abstract: pIE639 and Enterococcus faecium as hygienically relevant test bacteria. The development of the bacterial titer was evaluated by culturing on agar contact plates and investigating wood shavings. Survival of the test bacteria depended on different factors such as tree species, the initial inoculum size and the characteristics of the inoculated strain. The bacterial titer decreased fastest on pine compared to other woods (spruce, beech, poplar) and plastic. After bacterial infestation only pine wood was germ-free at the surface and in the inner structure after a few hours. The survival of the bacteria on poplar and beech was comparable to their survival on plastic. The study indicated that an antibacterial effect of wood, especially for pine, is caused by the hygroscopic properties of wood and the wood extractives. The antibacterial effect of pine wood was not influenced by the storage time of the wood following harvest or the functional condition of the wood up to a germ load of 108 CFU/cm2E. coli pIE639.

49 citations


Journal ArticleDOI
TL;DR: In this paper, an investigation was carried out on 20 cultivated larch trees (hybrid test area ‘Bomigrain’’ forestry district Rothenbuch) selected according to phenotypic criteria.
Abstract: Material and methods Investigations were carried out on 20 cultivated larch trees (hybrid test area ‘‘Bomigrain’’ forestry district Rothenbuch) selected according to phenotypic criteria. These trees formed the basis of a new breeding program to improve the growth, stem shape and especially the wood quality of larch trees. Two parts of a stem disc taken from each of the 20 larch trees (trunk height 1⁄4 1 m) were analysed: a) inner heartwood (IH); b) outer heartwood (OH, 3 cm within the sapwood/ heartwood border). To determine the extractives, the wood was first ground, adding solid CO2, sieved, and then successively extracted in a Soxhlet apparatus for 6 h and 4 h, using cyclohexane – ethanol (2:1) and ethanol respectively. Together, both extraction steps yield the total amount of extractives related to wood meal (oven-dry). In analogy to EN 113 (1996), the natural durability tests were carried out using the Kolle-flask method. Determination of mass loss after 12 weeks’ exposure to fungi was carried out using three different test fungi, choosing one representative of each decay type for each test: Coniophora puteana (brown rot), Trametes versicolor (white rot), Chaetomium globosum (soft rot). For each fungus and tree, 20 specimens were used. All decay tests were carried out simultaneously. Small pine sapwood blocks served as controls.

49 citations


Journal ArticleDOI
TL;DR: In this article, it was found that particleboards bonded with EMDI exhibited superior mechanical properties than those bonded with PMDI, particularly noticeable when the resins were applied at a rate of 2%.
Abstract: The purpose of this paper was to determine which of the isocyanate resins, PMDI or EMDI, was better for use in particleboard manufacture. It was found that particleboards bonded with EMDI exhibited superior mechanical properties than those bonded with PMDI. This was particularly noticeable when the resins were applied at a rate of 2%. At this low dosage EMDI satisfied EN 312 criteria for boards in interior fitments while 4% was needed to meet the requirements for load bearing panels in humid conditions.

Journal ArticleDOI
TL;DR: In this paper, ring-cut strands were acetylated by reaction with acetic anhydride at 120 °C for periods of 30 and 60 minutes, and the results indicated a weight gain of 11.2% and 20.4% respectively.
Abstract: ) ring-cut strands were acetylated by reaction with acetic anhydride at 120 °C for periods of 30 and 60 minutes. The results indicated a weight gain of 11.2% and 20.4% respectively. Treated and untreated strands were used to form laboratory boards, which were tested in accordance with EN standards. Boards made from these acetylated strands exhibited significantly lower thickness swelling and water absorption when compared with the control. The internal bond strength (IBS) of test boards was significantly lowere (−19%), but still within International standards, than the control boards, and failure was due to resin bond failure. This would suggest that lower resin dosing could partially offset acetylation costs in industrially produced boards. Finally, we observed that boards made with acetylated strands were less compressible than the control boards.

Journal ArticleDOI
TL;DR: In this article, a systematical approach to the properties of wood impregnated with different water-based melamine resins was presented to provide a basis for further research, and ten commercially available methylated melamine formaldehyde resins with increasing ratios of melamine to formaldehyde have been compared in respect of their influence in dimension stabilisation, sorption behavior, formaldehyde emissions, and water repellency of the treated wood.
Abstract: This paper presents a systematical approach to the properties of wood impregnated with different waterbased melamine resins, to provide a basis for further research. Therefore, ten commercially available methylated melamine formaldehyde resins with increasing ratios of melamine to formaldehyde have been compared in respect of their influence in dimension stabilisation, sorption behaviour, formaldehyde emissions, and water repellency of the treated wood. The dimension stabilisation caused by resin molecules that penetrated the wooden cell wall correlated with the molar mass of the resins used for impregnation. The changes in the sorption isotherms were attributed to a bulking effect. Formaldehyde emissions during and after curing increased with an increasing ratio of formaldehyde to melamine in the resins.

Journal ArticleDOI
TL;DR: In this article, the concentration of chemical components in the kiln atmosphere at regular time intervals and determining air-flows and temperature differentials across the stack were assessed by measuring the concentration and concentration of volatile organic compounds (VOC) at 100 °C dry bulb and 70 °C wet bulb.
Abstract: D. Don) at 100 °C dry bulb and 70 °C wet bulb, were assessed by measuring the concentration of chemical components in the kiln atmosphere at regular time intervals and determining air-flows and temperature differentials across the stack. The volatile organic compounds (VOC) were trapped on activated carbon and analyzed by GC-MS. The aldehydes were trapped in 2,4-dinitrophenol-hydrazine solution and the aldehyde derivatives analysed by HPLC. Polar compounds were trapped in water and then alcohols were analysed by GC and organic acids by ion exchange chromatography. The two major VOC found were α-pinene and β-pinene, which made up 90% of the total discharge (405 g/m3 wood). Most of the VOC fraction was released during the early stages of drying. The release of potentially hazardous components (formaldehyde, acetaldehyde, furfural) was found to be relatively low (1.1, 8.7, and 0.1 g/m3 wood, respectively) provided the kiln emissions are well dispersed, these levels of release are unlikely to cause adverse environmental effects.

Journal ArticleDOI
TL;DR: In this article, a three-step synthesis of particleboard resins is described, where the polymeric part is formed from condensation of formaldehyde with first amount of urea, and the monomeric part formed after addition of second part of Urea.
Abstract: C NMR spectroscopy. The three-step synthesis produces the resin consisting of two parts: the polymeric part from condensation of formaldehyde with first amount of urea, and monomeric part formed after addition of second part of urea. Some differences in structure depending on details of synthesis are of temporary character and level mainly in transhydroxymethylation from polymeric to monomeric part of resin. The reactions occuring after addition of second urea and following during storage are considered as one continuous process. Methylenes adjacent to secondary and tertiary amino groups form only during acid condensation. The main reaction during storage is the formation of methylenes adjacent to secondary amino groups. This reaction occurs between free terminal hydroxymethyl and amino groups of both resin parts. The physical and mechanical properties of particleboards confirm the close performance characteristics of studied resins. Particleboards satisfy requirements for general purpose boards P2 and emission standard E1.

Journal ArticleDOI
TL;DR: In this article, the authors validate the technical feasibility of making one layer experimental particleboard from coconut chips bonded with EMDI isocyanate resin and show that it is possible to satisfy the ANSI A2081-1998 standards for particleboards.
Abstract: This article validates the technical feasibility of making one layer experimental particleboard from coconut chips bonded with EMDI isocyanate resin The European Standards for particleboards used in interior fitments (EN 312; P2 and P3 boards) were satisfied at dosing rates of 4% EMDI The P4 load bearing board used in dry conditions, however, required a higher dosage rate of 6% EMDI with 1% wax When the data was evaluated using the ANSI A2081‐1998 standards for particleboards, it was found that the modulus of rupture and internal bond were easily satisfied with an application of 6% EMDI, however, a higher dosing rate of 8% EMDI resin and 05% wax was needed mainly to satisfy the thickness swell criteria Although these high resin application rates for particleboards made with coconut chips may not be economically practical for some uses, this valuable resource does show some promise for P2 and P3 boards It is suggested that a combination of coconut chips with industrial wood chips may be explored in order to improve the thickness swelling properties of the particleboards Einschichtige Laborplatten aus Cocosnus-Chips

Journal ArticleDOI
TL;DR: In this paper, a board with a dry I.B. strength of up to 0.34 MPa, a formaldehyde release well within the emission class E1 and certificate as normal flammable and not burning dripped off (DIN 4102-B2) was fabricated by mixing hemp shaves with a borate-modified mimosa tannin-hexamine binder and press the masses as fast as 6 s/mm thickness at 70°C to one-layer boards.
Abstract: , with a dry I.B. strength of up to 0.34 MPa, a formaldehyde release well within the emission class E1 and certificate as normal flammable and not burning dripped off (DIN 4102-B2) were fabricated by mixing hemp shaves with a borate-modified mimosa tannin-hexamine binder and press the masses as fast as 6 s/mm thickness at 70°C to one-layer boards. Different drying processes indicate that fast drying at ˜100°C is needed both for satisfactory strengths and for a sufficient dimension stability performance of soaked samples, but, as well for a lower boron leaching during soaking. For dry environments the resistance to fungal attack is sufficient enough to have boards for interior application.

Journal Article
TL;DR: In this article, the relationship between changes in tensile properties and structural integrity of wood during weathering was investigated, and the changes during exposure were analysed and were shown to be consistent with fractographic evidence of the structural changes in wood.
Abstract: This paper describes an investigation into the relationship between the changes in tensile properties and structural integrity of wood during weathering. Investigated species were Scots pine (heartwood and sapwood, and separately earlywood and latewood), and Norway spruce. The photodegradation was monitored through the changes in microtensile strength of wood during natural and artificial UV-weathering (thin strip method), and by subsequent FE SEM microscopical analysis of transverse-fracture surfaces of the strips. The tensile strength changes during exposure (initial increase and two following phases of decrease) were analysed and were shown to be consistent with fractographic evidence of the structural changes in wood. These include the breakdown of compound middle lamella (CML), the thinning of cell walls and the development of brittleness of the secondary walls. The mechanism of failure is essentially different in earlywood and latewood, and the microtensile strength is predominantly determined by the latewood portions within growth rings.

Journal ArticleDOI
TL;DR: In this article, the authors examined the penetration of PVA glue by light microscopy and scanning and transmission electron microscopy on wood cells and found that the wood cells were greatly distorted and cell walls were extensively damaged, particularly at and near the glue line.
Abstract: wood cells and penetration of PVA glue was examined by light microscopy and scanning and transmission electron microscopy. After planing with dull knives the wood cells were greatly distorted and cell walls were extensively damaged, particularly at and near the glue line. In comparison, sharp knives caused much less damage to cell walls and the cells had a normal or near-normal appearance. These features are discussed in detail in relation to glue penetration and the performance of glue joints after planing with sharp and dull knives.

Journal ArticleDOI
TL;DR: In this paper, a transient model for moisture transport in wood is presented, based on Fick's law with water vapour pressure and temperature as driving potentials, and a model for hysteresis has been proposed and included in the model.
Abstract: This article presents a transient model for moisture transport in wood. The model is based on Fick's law with water vapour pressure and temperature as driving potentials. A model for hysteresis has been proposed and included in the model. Comparisons between experimental results presented in Part 1: Sorption measurements of spruce exposed to cyclic step changes in relative humidity (Time 2002) and calculations have been performed. The model only deals with moisture transport in the hygroscopic region, liquid water is not included.

Journal ArticleDOI
TL;DR: In this paper, a new model is proposed for the structural analysis of corner joints, where they are considered as a macroscopic and interactive part of box-type furniture, and the stress concentration areas in the model are developed as in the physical joints.
Abstract: This article explores the possibility of analysing the stress and strain state in corner joints, typically found in furniture box-type structures, by using Finite Element Analysis (FEA). Based upon experimental research, a new model is proposed for the structural analysis of corner joints, where they are considered as a macroscopic and interactive part of box-type furniture. The fixing components, which connect the elements of physical joints, are replaced by elastic finite elements, the properties of which are determined experimentally. As a result, the stress concentration areas in the model are developed as in the physical joints, and the stress-strain state in corner joints can be accurately predicted. Finally, the deflection of cabinet furniture is predicted and the results obtained are compared to some similar published results.

Journal ArticleDOI
TL;DR: In this paper, a comparison of the standard method with the advanced extraction method clearly showed that the lower solvent demand and the thoroughly removal of the solvent at the end of an extraction step increased the effectiveness of the following washing step.
Abstract: Extraction of wood meal is generally the first, very time consuming step during the wet chemical analysis of wood and wood components. Solvents like toluene, benzene, dichloromethane, ethanol, methanol and water with increasing polarity are used in accordance with standard methods using a Soxhlet apparatus. The comparison of the standard method with the advanced extraction method clearly showed that the lower solvent demand and the thoroughly removal of the solvent at the end of an extraction step increased the effectiveness of the following washing step. The time need for the determination of the extractives contents and the standard deviations of the repeated measurements could be halved.

Journal ArticleDOI
TL;DR: In this paper, the color changes in sapwood and heartwood evolution were analyzed according to the previous results obtained in laboratory and showed that the sapwood color changes quickly during the first 10 hours and definitely after 30 hours of industrial treatment.
Abstract: ) logs, measured during boiling water process under industrial conditions. The colour changes in sapwood and heartwood evolution were analysed according to the previous results obtained in laboratory. As it was expected, the sapwood color changes quickly during the first 10 hours and definitely after 30 hours of industrial treatment. Its colour is darker and redder. Heartwood behavior is quite different because its colour is changing slowly during the first 10 hours and important changes are occuring after the 39 first hours. These mean results were obtained on the four logs studied. This work precise the particular behavior of the color of wood during boiling and the efficient method used. This study may be used by industries, which are concerned by heating treatment before slicing, and applied to other species.

Journal ArticleDOI
TL;DR: Among the compounds the monoterpenes exist in minor amounts while the sesquiterpenes including their oxygenated members as well as sesQUiterpene alcohols consist of the majority of the whole substances as discussed by the authors.
Abstract: , J. foetidissima and J. oxycedrus. Among the compounds the monoterpenes exist in minor amounts while the sesquiterpenes including their oxygenated members as well as sesquiterpene alcohols consist of the majority of the whole substances. The existence of some compounds of the oils might be attributes of the species and their sap- and heartwood. On the other side though notable differences, the essential oils of Turkish juniper woods resemble the commercial cedar wood oils.

Journal ArticleDOI
TL;DR: In this paper, the authors present the principle of operation of the hybrid dynamically balanced saw frame driving system with the kinetic energy accumulator connected in parallel, which allows the reduction of the mass and dimensions of the machine, to eliminate a huge and expensive foundation, and to increase the working speed.
Abstract: In frame sawing machines, where a saw frame is driven by a crank mechanism, an inertial force produced by the saw frame cyclic motion significantly affects the machine foundation and also the saw frame driving system. This paper discusses the question how these serious using difficulties in machine performance can be eliminated. The authors present the principle of operation of the hybrid dynamically balanced saw frame driving system with the kinetic energy accumulator connected in parallel. The findings of numerical analysis are: this solution allows us to eliminate changing loads of the driving system and permits a reduction of the mass and dimensions of the machine, to eliminate a huge and expensive foundation, and to increase the working speed.

Journal ArticleDOI
TL;DR: The use of wood as a shock absorber in containers for radioactive materials and the need of designers for good quality mechanical characteristics had lead to investigate the behavior of wood under multiaxial dynamic compression as discussed by the authors.
Abstract: The use of wood as a shock absorber in containers for radioactive materials and the need of designers for good quality mechanical characteristics had lead us to investigate the behaviour of wood under multiaxial dynamic compression. This paper presents the main experimental results of the static and dynamic compression we performed on small samples of wood during this study. These results are presented as analytical experimental models to be used in Finite Element Codes.

Journal ArticleDOI
TL;DR: In this article, the effects of wood characteristics and the pulping process on mechanical pulp fibres have been investigated, and it was shown that reducing fibre wall thickness and increasing fibre splitting was beneficial for improved surface smoothness and opacity.
Abstract: The thesis comprises three parts: Existing methods for characterisation of fibre crosssections have been improved, and new methods have been developed. These methods have then been applied to study the effects of wood characteristics and the pulping process on mechanical pulp fibres. Links have been established between fibre structure and paper properties such as surface smoothness and light scattering coefficient.New methods, based on SEM-images and image analysis, are described for providing cross-sectional fibre dimensions for large fibre populations, for wood tracheids (app. 60 000 tracheids in a wood trunk) and for processed pulp fibres (app. 1000 fibres per sample). The methods are suited e.g. for evaluation of changes in the fibre cross-sections from wood to the finished paper, or for mapping of fibre parameters within and between growth rings in a wood trunk. The treatment of data is discussed, showing how one may examine the changes in different groups of fibres (earlywood fibres, latewood fibres, split fibres) throughout a process.It is known from the literature that groundwood-based paper is superior to TMP-based paper with respect to printability. Fibres from SGW and PGW-pulp were found to be much more split in the longitudinal direction than TMP-fibres at comparable freeness. Intact groundwood fibres had thicker walls than intact TMP-fibres, but nevertheless super calendered hand sheets made from groundwood fibres were less roughened by moistening than were TMP-based sheets. Both for groundwood pulps and for TMPpulps, it was shown that reduced fibre wall thickness and increased fibre splitting was beneficial for improved surface smoothness and opacity.Latewood defibrate easier than earlywood during refining. In the case of grinding, there was no particular preference for earlywood or latewood to be defibrated. Reject refining of groundwood reject was, however, found to be very important for defibration of latewood-containing shives. Pulps made from a raw material with more compact fibres (high wall area to lumen area ratio) were found to defibrate easier, and contain less shives. It was found that refining tends to reduce wall thickness most on thickwalled parts of the fibre, thus causing a reduction of the wall thickness variation around the perimeter.Earlywood fibres were found to be preferentially split during refining. Most fibre splitting occurs during the primary stage, while the fibres are firmly attached to chips or fibre bundles. Latewood fibre wall thickness decreases considerably more than earlywood fibre wall thickness during refining. It seems that choosing an appropriate raw material is more effective than using excessive energy on reducing the wall thickness of thickwalled fibres. Earlywood fibres became more flattened during refining compared to latewood fibres, possibly due to repeated compressions and relaxations in the refiner.The energy consumption to a given freeness was found to be considerably larger for Scots Pine than for Norway Spruce. However, the fibre transverse dimensions did not differ much between Norway Spruce and Scots Pine. Pine pulps were far less developed than spruce pulps at similar energy level. A possible explanation for the large energy consumption may be that redistribution of extractives at the fibre surface could reduce friction in the refiner. This hypothesis should be further explored.The results in this study improve the knowledge of which fibre parameters that matter for surface smoothness and opacity of wood-containing publication paper. Further, this study elucidates how important fibre parameters such as wall thickness and fibre splitting are altered during a refining process. The results may be utilized to identify possible ways of modifying the TMP-process in order to produce paper with improved surface smoothness and opacity.

Journal ArticleDOI
TL;DR: In this article, a simple method was used to estimate the economic belt life, which will help derive effective belt change schedules in order to enhance the productivity of the process and suggest that the sanding process is suitable for low to moderate stock removal, for it ensures optimal process economics.
Abstract: ) as a raw material for high-volume furniture production, information on its sanding properties is relatively sparse. This study was carried out to provide some fundamental understanding of the sanding properties of the material, from an industrial perspective. The results suggest that the sanding process is suitable for low to moderate stock removal, for it ensures optimal process economics. Further, silicone carbide abrasive belts perform better than aluminum oxide abrasive belts for the sanding of Rubberwood. A simple method was used to estimate the economic belt life, which will help derive effective belt change schedules in order to enhance the productivity of the process.

Journal ArticleDOI
TL;DR: In this paper, the authors show that the moisture sorption process is a two-step process with the major change in moisture content in the first fast initial part and the major part of the moisture change happens within a relatively short period of time.
Abstract: ) have been exposed to repetitive daily and weekly step changes in relative humidity with the surrounding temperature at an approximate constant level. The results show that the moisture sorption is a two-step sorption process with the major change in moisture content in the first fast initial part. The major part of the moisture change happens within a relatively short period of time. No significant phase lag has been observed for neither transverse nor longitudinal specimens up to 10 mm thickness. The moisture change in absorption is slightly different from the moisture change in desorption. Curves in absorption and desorption for specimens with both transverse and longitudinal direction are rather similar in shape.

Journal ArticleDOI
TL;DR: In this paper, the authors used resols containing 36% reactive solids, the tannins representing aprox. 20% of the total glue consumption in double glue line.
Abstract: adhesive consumption in double glue line, which is significantly lower than the aprox. 400 g/m2 allowed by commercially available phenol-formaldehyde adhesives. The adhesives prepared with resols containing 36% reactive solids, the tannins representing aprox. 20%, has permitted the preparation of eucalyptus plywood boards exceeding the requirements of the European norm for exterior grade plywood.