Classification of Principal Wood Species in China Based on the Physiomechanical Properties

Many tree species are planted in China with variable properties and usage.Toward exploring the structure-properties relationships of wood and classifying the species more reasonably,the physiomechanical properties of the domestic wood species in China were analyzed statistically.According to the correlation analysis,the mechanical properties were closely related to the wood density.Except impact toughness and cleavage strength,the correlation coefficients between mechanical properties and densities were more than 0.8.However,shrinkage properties showed fewer correlations with densities,and the coefficient was no more than 0.7.Primary component analysis was proved to be feasible to explore the information of the physiomechanical properties.Two principal components(PC1 and PC2)could account for most of the information.PC1 and PC2 were designated as density-dominated and shrinkage-associated factors,respectively.The domestic wood species in China could be classified into 4 clusters based on their physiomechanical properties.According to the cluster results,reasonable grading was proposed for air-dried density,volume shrinkage,modulus of rupture,compression strength parallel to grain and hardness in cross section.The statistical results brought insights into analyzing the physiomechanical properties of domestic Chinese wood species,which was helpful for developing strategies of tree breeding and technologies of wood processing.

Wood species identification using spectral reflectance feature and optimal illumination radian design

We developed a scheme based on wood surface novel wood recognition spectral features that aimed to solve three problems. First was elimination of noise in some bands of wood spectral reflection curves. Second was improvement of wood feature selection based on analysis of wood spectral data. The wood spectral band is 350-2500 nm, a 2150D vector with a spectral sampling interval of 1 nm. We developed a feature selection proce- dure and a filtering procedure by solving the eigenvalues of the dispersion matrix. Third, we optimized the design for the indoor radian＇s mounting height. We used a genetic algorithm to solve the optimal radian＇s height so that the spectral reflection curves had the best classification infor- mation for wood species. Experiments on fivecommon wood species in northeast China showed overall recogni- tion accuracy 〉95 % at optimal recognition velocity.

Effects of wood species and retention levels on removal of copper,chromium,and arsenic from CCA-treated wood using sodium hypochlorite

Chemical extraction, bioremediation, and electrodialytic processes have been extensively studied for removal of copper, chromium, and arsenic from wood treated with chromated copper arsenate （CCA）. However, one problem has not been addressed： the effects of wood species and retention levels on remediation efficiency. The objectives of this study were to investigate the effects of wood species and retention levels on removal of copper, chromium, and arsenic from CCA-treated wood samples using sodium hypochlorite. Our results showed that sodium hypochlorite （NaOC1） was very effective for removal of copper, chromium, and arsenic from CCA-C treated milled wood samples for all three species used in this study. The Cu, Cr, and As extraction efficiencies for red pine were 95 % Cu, 97 % Cr and 94 % As, for maple were 95 % Cu, 97 % Cr, and 98 % As at 4.0 kg m-3 retention levels, and for aspen were 95 % Cu, 92% Cr, and 91% As at 9.6 kg m-3 retention level, respectively. However, the results showed that wood species and initial retention levels of CCA-treated wood products played very impor- tant roles in terms of removal of Cu, Cr, and As.

Biomolecules of Interest Present in the Main Industrial Wood Species Used in Indonesia-A Review

As a tropical archipelagic country,Indonesia’s forests possess high biodiversity,including its wide variety of wood species.Valorisation of biomolecules released from woody plant extracts has been gaining attractive interests since in the middle of 20th century.This paper focuses on a literature review of the potential valorisation of biomolecules released from twenty wood species exploited in Indonesia.It has revealed that depending on the natural origin of the wood species studied and harmonized with the ethnobotanical and ethnomedicinal knowledge,the extractives derived from the woody plants have given valuable heritages in the fields of medicines and pharmacology.The families of the bioactive compounds found in the extracts mainly consisted of flavonoids,stilbenes,stilbenoids,lignans,tannins,simple phenols,terpenes,terpenoids,alkaloids,quinones,and saponins.In addition,biological or pharmacological activities of the extracts/isolated phytochemicals were recorded to have antioxidant,antimicrobial,antifungal,anti-inflammatory,anti-diabetes,anti-dysentery,anticancer,analgesic,anti-malaria,and anti-Alzheimer activities.Aside from these remarkable characteristics of woody plant extractives,further studies concerning the valorisation of these extractives in the fields of nutraceutical,cosmetic,bio-control,bio-stimulation,and other advanced applications would be of interest.

Determination of the Properties of Some Selected Timber Species for Structural Application

One of the alternative sustainable and green construction materials to concrete is timber. Timber is of numerous varieties, and this acts as a barrier to the extent of its usage, especially in structural application. Despite many researches on wood’s mechanical and physical properties, only a few are geared toward the structural application of wood. The present work investigated the mechanical properties of five timber species;Gmelina arborea, Tectona grandis (Teak), Terminalia superba (Afara), Ayin (Anogeissus leiocarpus), and Acacia (Robinia pseudoacacia), to determine their suitability for constructing long-span roof trusses. These are available in the South Western part of Nigeria. Their mechanical properties;bending strength, compressive strength, shear strength, tensile strength, Modulus of Elasticity (MOE), Modulus of Rupture (MOR), and density, were determined in the laboratory. The results obtained showed that all the timber types, except Terminalia superba (Afara), have higher values of mechanical properties than the values that are obtainable for classes of strength D30 to class D70 in the British Code of Practice. It means these species are of higher quality than the stipulated strength classes in the British code. The results also show that the order of relevance of the species for structural design (or work) is Acacia (Robinia pseudoacacia), Ayin (Anogeissus leiocarpus), Gmelina Arborea, and Tectona grandis (Teak). Terminalia superba (Afara) is not recommended for structural works.

Matrix Assisted Laser Desorption Ionization Time of Flight(MALDI-TOF)-Mass Spectrometry and^(13)C-NMR-Identified New Compounds in Paraberlinia bifoliolata(Ekop-Beli)Bark Tannins

Extracts of plant origin,particularly tannins,are attracting growing interest for the sustainable development of materials in the industrial sector.The discovery of new tannins is therefore necessary.The aim of this work was to contribute to the understanding of the properties of Paraberlinia bifoliolata tannin by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectroscopy MALDI-TOF/MS and Carbon 13 Nuclear Magnetic Resonance(13C NMR).The chemical composition of tannin extracted from Paraberlinia bifoliolata bark was determined,as was the mechanical strength of the resin hardened with Acacia nilotica extracts.Yield by successive water extraction was 35%.MALDI-TOF/MS analysis revealed the presence of three new compounds in this tannin,previously unknown in this family of extracts.These are 3-hydroxyproline acid,N-methyl-4-hydroxypipecolic acid and N-methyl-5-dihydroxypipecolic acid.The identification of the above molecules means that this tannin can be used for industrial applications,as a resin in the manufacture of particleboard and in the formulation of green corrosion inhibitors.This information is reinforced by 13C NMR spectrometry,which indicates the presence of several polyflavonoid units,confirming the condensed nature of the tannin.Thermomechanical analysis of the resin formed by the purified tannin of Paraberlinia bifoliolata to which a vegetal biohardener has been added provided a Modulus of Elasticity(MOE)value of 4840 MPa at 150℃,confirming its possible use as a binder resin in the manufacture of wood panels as well as for the formulation of a corrosion inhibitor.

A feasibility study of using two-component polyurethane adhesive in constructing wooden structures

This investigation was conducted to determine the feasibility of using a two-component polyurethane （PUR） adhesive, with special waterproof properties, in constructing wooden structures. We designed and conducted tests to compare the shear strength and adhesion performance of PUR with polyvinyl acetate （PVAc） adhesive on block-shear specimens constructed of oriental beech （Fagus orientalis L.）, fir （Abies alba Mill.）, poplar （Populus deltoides Bartr.）, white oak （Quercus alba L.）, sycamore （Platanus orientalis L.） and white walnut （Juglans cinerea L.）. The values of the percentage of wood failure were also determined in specimens constructed with each adhesive. The highest shear strength values of both adhesives were obtained in specimens constructed of beech, while the lowest shear strength values were obtained in fir and poplar specimens. Average shear strength of the PUR adhesive was 16.5% higher than that of the PVAc adhesive. Specimens constructed of fir, poplar and sycamore were characterised by the highest percentages of wood failure, whereas the lowest average percentages of wood failure were obtained in beech and oak specimens. With the exception of oak specimens, there was no statistically significant difference between percentage of wood failure among the PUR and PVAc adhesives. Generally, the PUR adhesive showed an acceptable adhesion performance on wood materials used in our study.

Mechanical Properties of Terminalia catappa from Ghana

Ghana is rich in forest resources, of whichTerminalia catappa, a wood species of common occurrence is one. Even though sometimes it is used for decorative purposes, however, it grows in the wild. It grows in almost all the regions of the country and does well in the tropics. The parts of the tree such as the leaves, fruits and seeds have been known to be very useful for medicinal and other uses. Some work on the strength properties of the leaves and other parts has also been done, however, strength properties of the wood are yet to be explored. In this study, its mechanical properties such as bending strength, compression parallel to the grain, and shear parallel to the grain properties were determined. The British (BS 373, 1957) and American Society of Testing Materials’ specifications (ASTM D143, 1983) using testing methods for small, clear specimens of wood were used in determining the properties. The results showed that at 18% moisture content the wood has a density of 520 kg/m3 with a mean modulus of rupture of 86.04 Mpa, compressive strength parallel to the grain of 42.02 Mpa, modulus of elasticity of 10,500 Mpa, and shear strength parallel to the grain of 16.42 N/mm2. These strength properties are comparable to that of Strombosia glaucescens. Therefore, T. catappa can be used in applications where this species is used.