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1.
Ilpo Niskanen Jorma Heikkinen Jukka Mikkonen Anni Harju Henrik Heräjärvi Martti Venäläinen Kai-Erik Peiponen 《Journal of Wood Science》2012,58(1):46-50
The purpose of this study was to determine the effective refractive index of thermally modified Scots pine (Pinus sylvestris L.) wood specimens as a quantitative measure regarding the change of wood density which is due to the thermal modification.
The refractive index of thermally modified Scots pine wood was obtained by introducing pine wood powder into an immersion
liquid and measuring light backscattering with a homebuilt multifunction spectrophotometer. The present method provides useful
information that in principle can be applied, for example, in the optimization of the thermal modification process and inspection
of the quality of thermally modified wood. 相似文献
2.
We evaluated fungal decay and mold resistance, leaching, and water absorption of nano-compounds and Paraloid B72® (PB72) in treated wood specimens to develop new methods of consolidation by combining nano-particles and consolidants. Scots pine wood specimens were treated with dispersions of nano-CuO, nano-ZnO, nano-B2O3, nano-TiO2, and nano-CeO2. PB72 treatments of nano-particle-treated wood specimens were then carried out by either vacuum or immersion for 24 h. Previously, decayed wood specimens were also consolidated with the nano-compounds and PB72. PB72 treatments reduced element release from treated wood specimens. Nearly all nano-compounds + PB72 treatments increased the biological performance of treated wood specimens against decay fungi tested. PB72-only treated wood specimens had the highest weight losses in decay tests. No improvements were obtained in mold resistance tests when the nano-compounds and PB72 were combined. In nano-compound-only treatments, unleached specimens showed slightly lower water absorption values compared to untreated control specimens. Incorporation of PB72 into nano-compound-treated wood specimens resulted in considerably lower water absorption and volumetric swell. In previously decayed specimens treated with the nano-compounds and PB72 solution, water absorption after 2-h immersion declined compared to control specimens. 相似文献
3.
Colour responses from wood,thermally modified in superheated steam and pressurized steam atmospheres
《Wood material science & engineering》2013,8(3-4):211-219
Abstract In this study, two different methods were used to produce thermally modified wood. One was carried out in a typical kiln drying chamber using superheated steam (SS) and the other used pressurized steam in an autoclave cylinder (PS). Overall, both processes followed the same principles and the wood was not treated with any chemicals. Two wood species were studied, Scots pine (Pinus sylvestris) and Norway spruce (Picea abies). Treatments in the autoclave were carried out under pressure using temperatures of 160°C, 170°C and 180°C. Temperatures of 190°C and 212°C were used in treatments in the chamber at normal air pressure. The colour was measured using L*C*H colour space. Results for both species showed that similar L* (lightness) can be reached at lower (20–30°C) temperatures using PS compared with SS treatment. The hue angle of PS-treated wood was smaller than that of SS-treated wood. No significant difference in C* (chroma) was detected. The difference in E value between PS- and SS-treated wood was smaller for Norway spruce than for Scots pine. The residual moisture content was about 10% higher in wood treated by the PS process compared with the SS process. 相似文献
4.
The aim of this study was to determine changes in crystallinity and crystalline unit cell type of heat-treated Scots pine
(Pinus sylvestris L.) and Uludağ fir (Abies nordmanniana stev. subsp. bornmuelleriana Mattf.) wood samples by means of FT-IR spectroscopic method. Heat treatment was applied on the test samples in an oven at
three different temperatures (120, 150, and 180°C) and for two different periods of time (6 and 10 h) under atmospheric pressure.
It was designated that crystallinity of both Scots pine and Uludağ fir wood samples increased during heat treatment depending
on the duration. However, monoclinic structure in crystalline unit cells of Scots pine and Uludağ fir wood samples converted
to triclinic structure when heat treated. It was estimated that monoclinic structure was dominant in the crystalline unit
cell. It was established that the crystalline structure of Scots pine wood samples was more affected by heat treatment than
that of Uludağ fir wood samples. 相似文献
5.
Hermann Pleschberger Alfred Teischinger Ulrich Müller Christian Hansmann 《Wood material science & engineering》2014,9(2):92-101
Effects of different thermal treatments (maximum treatment temperatures of 200, 210 and 220°C for 2.5 hours) on solid spruce (Picea abies L. Karst.) and ash (Fraxinus excelsior L.) were investigated in this study. The fracture behaviour in radial/longitudinal as well as in tangential/longitudinal and the change of the wood colour (CIEL*a*b* colour space) on all principal anatomical surfaces (cross sectional, radial and tangential) were analysed. The specific fracture energy and the maximum breaking load decreased almost significantly after all thermally treated samples in comparison to the untreated (standard dried) sample. The wood colour changed also significantly, in particular the lightness decreased with increasing intensity of thermal treatment on all investigated surfaces. A comparison of the percentage loss of the different fracture and colour values has shown a strong correlation between the maximum breaking load and the lightness after several thermal treatments, in both investigated crack propagation systems, on all measured surfaces and for both analysed species. 相似文献
6.
Semi-isostatically densified and native wood samples of Scots pine and European birch were soaked in water. The swelling coefficients
as well as the swelling pressure, that arose when the specimens were restrained in some way prior to the swelling, were measured
using a universal testing machine equipped with a high resolution load-cell and an external extensometer. As densified wood
swells, the native structure is almost restored and the swelling pressure became twice as high as for native wood in the most
compressed directions (radial for pine and birch). That cell-shape recovery increases the swelling pressure can explain the
problems with imbalance in laminated constructions where densified wood is used. The possibility to predict the swelling pressure
from basic material properties was evaluated. The correlations between swelling pressure and material properties were strong
enough to yield good predictive models. 相似文献
7.
Ahmed Mohareb Marie France Th��venon Edmond Wozniak Philippe G��rardin 《Wood Science and Technology》2011,45(3):407-417
In this study, the use of polyvinyl alcohol (PVA) as boron fixative agent was investigated. Two levels of PVA (2.5 and 4%) were evaluated with disodium octaborate tetrahydrate (DOT) at three concentrations (1, 2 and 4% boric acid equivalent (BAE)) using a double vacuum impregnation process on Scots pine sapwood specimens. Leaching was performed according to a laboratory leaching procedure. Boron analysis using atomic absorption spectrometer showed a significant reduction in boron leachability for the samples treated with both concentrations of PVA when compared to the stand-alone boron treatment leading to boron retentions capable of preventing wood biological degradations. Decay resistance of the leached specimens was evaluated using the brown rot fungus Poria placenta. Even if complete protection was not fully achieved, an improvement in decay resistance was observed for the samples treated with DOT in presence of PVA. This leak of efficacy was attributed to a decrease in the biological activity of the complexed boron against fungi. Durability of treated wood against termite attack, evaluated using Reticulitermes santonensis, indicated a significant enhancement for the samples treated in presence of the fixative agent compared to the pure boron treatment. 相似文献
8.
Studying the impregnation and distribution of oil-based preservative in dried wood is complicated as wood is a nonhomogeneous, hygroscopic and porous material, and especially of anisotropic nature. However, this study is important since it has influence on the durability of wood. To enhance the durability of thermally modified wood, a new method for preservative impregnation is introduced, avoiding the need for external pressure or vacuum. This article presents a study on preservative distribution in thermally treated Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) sapwood using computed tomography scanning, light microscopy, and scanning electron microscopy. Secondary treatment of thermally modified wood was performed on a laboratory scale by impregnation with two types of preservatives, viz. Elit Träskydd (Beckers) and pine tar (tar), to evaluate their distribution in the wood cells. Preservative solutions were impregnated in the wood using a simple and effective method. Samples were preheated to 170 °C in a drying oven and immediately submerged in preservative solutions for simultaneous impregnation and cooling. Tar penetration was found higher than Beckers, and their distribution decreased with increasing sample length. Owing to some anatomical properties, uptake of preservatives was low in spruce. Besides, dry-induced interstitial spaces, which are proven important flow paths for seasoned wood, were not observed in this species. 相似文献
9.
杉木浸渍改性材的尺寸稳定性研究 总被引：1，自引：0，他引：1
利用聚乙烯醇缩甲醛改性剂对杉木木材进行浸溃改性，对其改性材的尺寸稳定性进行研究。结果表明：改性材的弦向、径向和体积干缩率与素材相比均有不同程度的下降；改性材的弦向、径向和体积湿胀率与素材相比也均有不同程度的下降，但当改性剂浓度超过20％时，下降才较明显；改性材吸水率随改性剂浓度的上升而下降，最大可由改性前的197％下降到改性后的155％；改性材的抗干缩系数（ASE）随改性剂浓度上升而增加，最大可达18．8％。杉木改性材的尺寸稳定性能要明显优于素材。 相似文献
10.
Scots pine sapwood (Pinus sylvestris L.) and beech (Fagus sylvatica L.) were impregnated with five waxes. The experiments indicate deep penetration into pine sapwood. Besides the viscosity,
an influence of the wax polarity is presumed. Wax penetrates pine wood deeply via the cross-section, but not sufficiently
enough to impregnate longer construction elements. However, the radial wax uptake exceeds the uptake via the tangential orientation
and guarantees complete soaking of the sapwood tissue. The lateral wax penetration within beech is quite low and irregular.
In addition to the temperature, a prolonged process procedure is decisive for an increasing wax uptake. As such, beech wood
vessel elements seem to be fully impregnable via the longitudinal surface after a longer process procedure. 相似文献
11.
Tahiana Ramananantoandro Miora F. Ramanakoto Andraina H. Rajemison Florent Eyma 《Annals of Forest Science》2013,70(6):649-658
Context
The knowledge of consumer preferences in wood furniture is crucial for the wood processing industries.Aim
This study aims to identify the attributes of wood that affect the preferences of consumers from the city of Antananarivo, Madagascar, for wooden furnishings.Methods
Quantitative measurements of the density and aesthetic properties of 12 wood species were carried out. The properties measured were the colour in the CIEL*a*b* colour space, the texture through greyscale image processing, and the density. Then, the wood specimens were subjected to sensory analysis with 100 consumers.Results
The results showed that the "density" was a prime criterion in choosing a wood species. Concerning the visual aspect, Antananarivo consumers generally liked slightly dark wood colour (L* around 52), tending towards yellow, with a visible oriented texture. The influence of socio-economic factors was also highlighted.Conclusion
These results are of prime importance in the search for alternative species to replace precious woods that are becoming rare. 相似文献12.
Heat-induced colour changes of pine (Pinus pinaster) and eucalypt (Eucalyptus globulus) wood 总被引：4，自引：0，他引：4
Bruno Esteves António Velez Marques Idalina Domingos Helena Pereira 《Wood Science and Technology》2008,42(5):369-384
Heat treatment of Pinus pinaster and Eucalyptus globulus wood was carried out by hot air in an oven for 2–24 h at 170–200°C and by steam in an autoclave for 2–12 h at 190–210°C.
The colour parameters L*, a* and b* were determined by the CIELAB method on radial, tangential and transverse sections of untreated and treated wood, and their
variation with regard to the treatment (ΔL*, Δa* and Δb*) were calculated in percent. For untreated eucalypt wood, lightness (L*) varied between 54.1 and 63.8% with a* between 7.4 and 8.5, and b* between 15.7 and 19.9. For untreated pine wood, L* varied between 67.3 and 76.1%, a* between 6.9 and 7.6 and b* between 16.3 and 24.1. Oven heat-treated wood became darker (ΔL* about 50% for 4% mass loss), and this was more for eucalypt wood under the same treatment conditions. In general, the contribution
of red (a*) and yellow (b*) colour decreased with heat treatment. The transverse section of the two species darkened less for both the treatments with
small differences between radial and tangential sections. Lightness decrease was related to chemical changes; with good correlations
with glucose (R
2 = 0.96), hemicelluloses (R
2 = 0.92) and lignin (R
2 = 0.86). As regards colour, the heat treatments showed an interesting potential to improve the wood quality for solid timber
products from pine and eucalypt. 相似文献
13.
Context
The development of multiple trait selection indices for solid (structure) wood production in the Scots pine (Pinus sylvestris L.) breeding program requires genetic variances and covariances estimated among wood quality traits including stiffness.Aims
Genetic control and relationships among Scots pine growth, fiber, and wood quality traits were assessed by estimating heritability, phenotypic and genetic correlation using a Scots pine full-sib family trial.Method
Wood quality traits including clearwood and dynamic acoustic stiffness were measured using SilviScan and Hitman in a 40-year-old progeny trial and by sampling increment cores of 778 trees of 120 families. Genetic parameters were estimated using the mixed model by the ASReml software.Results
Heritability ranged from 0.147 to 0.306 for growth, earlywood, transition wood and latewood proportion traits and from 0.260 to 0.524 for fiber dimension, wood density, MFA and stiffness traits. The highly unfavorable genetic correlation between diameter and whole core density (?0.479) and clearwood stiffness (?0.506) and dynamic acoustic stiffness (?0.382) was observed in this study.Conclusion
The unfavorable genetic correlations between growth traits and stiffness indicate that multiple traits selection using optimal economic weights and optimal breeding strategies are recommended for the advanced Scots pine breeding program. 相似文献14.
G. Tondi M. F. Thevenon B. Mies G. Standfest A. Petutschnigg S. Wieland 《Wood Science and Technology》2013,47(3):615-626
The impregnation process of Scots pine and beech samples with tannin solutions was investigated. The two materials involved in the process (impregnation solution and wood samples) are studied in depth. Viscosity of mimosa tannin solutions and the anatomical aspect of beech and Scots pine were analysed and correlated. The viscosity of tannin solutions presents a non-newtonian behaviour when its pH level increases, and in the case of addition of hexamine as a hardener, the crosslinking of the flavonoids turns out to be of great importance. During the impregnation of Scots pine (Pinus sylvestris L.) and beech (Fagus sylvatica L.), the liquid and solid uptakes were monitored while taking into consideration the different conditions of the impregnation process. This method allowed to identify the best conditions needed in order to get a successful preservative uptake for each wooden substrate. The penetration mechanism within the wood of both species was revealed with the aid of a microscopic analysis. Scots pine is impregnated through the tracheids in the longitudinal direction and through parenchyma rays in the radial direction, whereas in beech, the penetration occurs almost completely through longitudinal vessels. 相似文献
15.
Models for predicting microfibril angle variation in Scots pine 总被引：1，自引：0，他引：1
David Auty Barry A. Gardiner Alexis Achim John R. Moore Andrew D. Cameron 《Annals of Forest Science》2013,70(2):209-218
Context
Microfibril angle (MFA) is one of the key determinants of solid timber performance due to its strong influence on the stiffness, strength, shrinkage properties and dimensional stability of wood.Aims
The aim of this study was to develop a model for predicting MFA variation in plantation-grown Scots pine (Pinus sylvestris L). A specific objective was to quantify the additional influence of growth rate on the radial variation in MFA.Methods
Twenty-three trees were sampled from four mature Scots pine stands in Scotland, UK. Pith-to-bark MFA profiles were obtained on 69 radial samples using scanning X-ray diffractometry. A nonlinear mixed-effects model based on a modified Michaelis–Menten equation was developed using cambial age and annual ring width as explanatory variables.Results
The largest source of variation in MFA (>90 %) was within trees, while between-tree variation represented just 7 % of the total. Microfibril angle decreased rapidly near the pith before reaching stable values in later annual rings. The effect of ring width on MFA was greater at higher cambial ages.Conclusion
A large proportion of the variation in MFA was explained by the fixed effects of cambial age and annual ring width. The final model is intended for integration into growth, yield and wood quality simulation systems. 相似文献16.
Antje Pfeffer Patrik J. Hoegger Ursula Kües Holger Militz 《Wood Science and Technology》2012,46(1-3):63-72
Specimens of Scots pine sapwood (Pinus sylvestris L.) and beech wood (Fagus sylvatica L.) were treated with an amino-alkyl-functional oligomeric siloxane, a sodium water glass solution and 1,3-dimethylol-4,5-dihydroxyethylene urea (DMDHEU). Treated and untreated wood specimens were exposed outdoors without ground contact. After 9?months of outside exposure, all specimens showed discolouration caused by infestations of mould and staining fungi on the exposed wood surface. Fungi grown on the sample surface were isolated and identified by microscopic technique and sequencing of PCR-amplified DNA from the ITS region. Primarily, an infestation by ascomycetes and related deuteromycetes was found. The most dominant fungi were Trichoderma sp. and Epicoccum sp.. An infestation of Aureobasidium pullulans was only detected on untreated and DMDHEU-treated samples. There were only marginal differences of fungal infestation between the two wood species. 相似文献
17.
《Wood material science & engineering》2013,8(3-4):97-105
Abstract The indoor relative humidity in dwellings and offices is an important factor in building physics. The ability of hygroscopic materials and especially wood materials to store and release moisture helps to regulate the indoor climate naturally and to avoid extremes of humidity. In the present study, cyclic sorption experiments with coated Scots pine were performed. Materials with different coating compositions were exposed to day-to-day relative humidity changes. The moisture buffering capacity was estimated by a gravimetric method and the moisture buffer value was computed. The results show that the coating has a significant impact on the moisture buffering capacity of the underlying Scots pine. The moisture distribution in the wood sample was appraised for each coating system using a proton magnetic resonance imaging technique. This study confirmed that the dynamics of moisture exchange between the indoor environment and the wooden material during typical daily moisture fluctuations is confined to a few millimetres behind the air–wood interface. 相似文献
18.
《Wood material science & engineering》2013,8(4):186-195
Abstract This work was an investigation of the effect of nanoparticles on the durability of wood specimens exposed to artificial weathering. TiO2 and clay nanoparticles were mixed with preservative (Wolmanit CX-8) for improving the durability of Norway spruce (Picea abies). Impregnated and untreated specimens were subjected to Atlas Solar Simulator accelerated ageing test chamber for solar radiation and water spray exposure. The effectiveness of the treatment against colour and chemical changes was investigated using CIEL*a*b* colour measurements system and Fourier transform infrared analysis. The present study showed that the wood specimens that had been treated with preservatives containing nanoparticles were slightly more stable against artificial ageing than both untreated specimens and specimens treated with preservative alone. 相似文献
19.
Lars Hansson José Couceiro Bengt-Arne Fjellner 《Wood material science & engineering》2017,12(4):251-256
The aim of the present work was to use the displacement information generated from the spatial alignment in order to compute wood shrinkage in the radial and tangential directions in computed tomography (CT) images, and to compare the results with those obtained with computer-aided design software on the same images. To estimate the shrinkage coefficients from tomography images, wood specimens in the green state, equilibrium moisture content 15% and 8% state and oven dry condition were scanned. Specimens were taken from Norway spruce and Scots pine logs. The root-mean-square-error calculations showed acceptable small differences between the two measuring methods, which means that the algorithm is a useful tool for estimating the shrinkage coefficients in radial and tangential direction from CT images. This provides an image processing tool to monitor the dimensional changes during the drying and heat treatment process. 相似文献
20.
Eylem Dizman Tomak Elif Topaloglu Nurgul Ay Umit C. Yildiz 《Wood Science and Technology》2012,46(5):905-918
The objective of this study was to investigate the effect of accelerated aging on compression strength, modulus of rupture, modulus of elasticity, color change, volumetric swelling, and volumetric shrinkage of bamboo specimens with and without node sections. In the study, these properties were compared with those of Scots pine and beech wood specimens. Depending on bamboo sections, the aging procedure reduced modulus of rupture, modulus of elasticity, and compression strength. Bamboo specimens showed relatively high strength properties compared to wood specimens due to having high density. Strength properties increased from bottom to top of bamboo culms. The presence of nodes in the specimens reduced compression strength and modulus of rupture but affected modulus of elasticity slightly. Remarkable color changes in specimens were observed after aging. Volumetric swelling and shrinkage of bamboo specimens exposed to aging decreased probably due to heat effect of aging procedure. 相似文献