International Wood Products Journal

Red sandal wood (RSW) is one of the important natural materials yielding red colour for variety of applications. Extraction of natural dye attached to the wood matrix of RSW is difficult due to mass transfer resistance. The paper describes attempts to get efficient extraction of RSW at ambient conditions using ultrasound (even dispensing with organic solvents) as compared to magnetic stirring. Process parameters studied included the effect of time, temperature, ultrasound power, pulse mode and solvent ratio. Results indicate that up to 32% increase in yield of the sandal wood natural dye extract could be achieved using ultrasound. This methodology for RSW could be beneficial to enhance the yield and usage of this natural resource in an effective manner.

Practices for capturing employee creativity present an important opportunity for forest sector firms wishing to increase their innovation efforts. Since employees are the interface with customers and business processes, they are best positioned to have the insights necessary for improvements. Despite this obvious connection, the forest sector literature has only rarely addressed the mechanisms that might be used by forest industry companies to capture and implement employee creativity and ideas for innovation. Accordingly, this exploratory study investigates best practices utilised in four innovative firms. Using a qualitative approach, we find many commonalities among these firms. For example, each company provides autonomy to work teams and is open to employee ideas for improvement. Two of the four companies rely on customers for ideas. Based on these findings, we conclude that competitive advantage in the forest sector of the twenty-first century is also tied to people, in addition to raw materials or equipment.

In this paper, the ANSYS finite element analysis is applied to the pine backrest chair models. During the structure design progress, the Taguchi method for the robust design is applied. By means of the signal-noise ratio (SNR) factor effect analysis, the optimal design scheme of the structural quality of pine backrest chair is determined that the backrest chair is designed as trapezoidal seat frame, upper waling, bottom waling with II type and leaning back rear leg. Based on the above condition, the maximum equivalent stress is improved by 9.05% than the initial one, the maximum deformation is ameliorated by 14.42% and the SNR is significantly improved. When robust design is on the basic of Taguchi method, the robustness of structure quality characteristics can be enhanced. At the same time, the overall strength and stiffness of the furniture structure can be improved and the design cost can be reduced.

Accurate detection of surface defects plays a vital role in automated analysis of lumber quality in the wood industries. A new method, based on a genetic optimisation of energy model, is introduced here for defect detection in lumber images. In this method, a hypothesis testing framework is defined, first to separate defects from natural tissue of lumber. Then, the boundary of lumber is estimated by a decision function based on the energy optimisation method which is driven by an irregular parametric genetic approach. Performance of the proposed algorithm was evaluated on real captured lumber images containing several types of surface defects. The results demonstrate that the proposed method extracts the defects approximately 4.4% better than its alternatives while at the same time decreasing false detections by approximately 5.4%. The results obtained also show considerable improvements in accuracy and precision of the proposed method compared to other examined methods, especially when a low false detection (i.e. at least 10%) is desired.

An optimum artificial neural network and a partial least square with discriminant analysis regression were developed and tested for accuracy in distinguishing two wood species by using near-infrared (NIR) spectrum. A mixed population of kiln-dried wood boards of western hemlock (Tsuga heterophylla (Raf.) Sarg.) and amabilis fir (Abies amabilis (Dougl.) Forbes) were scanned by NIR and then a random sub-set was water saturated under vacuum conditions and scanned again. This design aimed to capture the effect of moisture content above the fibre saturation point on the separation algorithms. Our results revealed that both modelling techniques can be effective tools for species recognition achieving correct identification of over 86% for fir and 94% for hemlock on either kiln-dried or fully saturated boards.

Solid wood properties were examined in eight half-sib families of 4-year-old Eucalyptus camaldulensis trees selected for pulpwood production in Thailand. The effects of radial growth rate on solid wood properties were also discussed. The mean values of green moisture content (MC) and basic density (BD) at 1.2 m heights in each family ranged from 86.3 to 106.6% and from 0.49 to 0.57 g cm⁻³, respectively. Significant among-family differences were found in MC, BD and maximum height of interlocked grain (IG). However, no significant correlations were found between stem diameter and solid wood properties, with the exception of MC and BD at a 5.2 m height, and IG. Based on the results obtained, it is suggested that superior E. camaldulensis trees, with respect to both growth characteristics and solid wood properties, can be selected for pulpwood production.

This study assesses the potential of instrumented macrohardness testing for the fast and convenient characterisation of resin-treated wood. The effect of WPG (weight per cent gain; percentage mass of resin based on dry wood; high, low) and curing conditions (dry, wet) on hardness and indentation modulus of Scots pine (Pinus sylvestris L.) sapwood was investigated for two thermosetting resins, phenol formaldehyde and methylated melamine formaldehyde. Thickness of the treated specimens broadly confirmed the findings of earlier studies that dry curing conditions increase degree of cell wall penetration. Dry curing resulted in equal or lower hardness, but it mostly increased indentation modulus. Hardness improvement seems to depend on the overall reduction of the void volume fraction in the wood, while indentation modulus depends on cell wall modification. Therefore, indentation modulus is expected to show a much better correlation with dimensional stability and durability of resin-treated wood than hardness.

The extractive content of inner and outer heartwood of nine Scots pine trees from three different stands in Norway was determined by automated solvent extraction and biological screening tests were performed using basidiomycetes. The evaluation of mass spectra by means of a NIST library search shows that in the petroleum ether extracts α-pinene and carene as well as terpinene and cadinene derivatives are the main extractives found in both inner and outer heartwood. In the inner heartwood, however, these substance groups were found in lower quantities. These substances mainly have a hydrophobic effect. The screening tests indicate that also extractive-rich heartwood is extremely degraded by Poria placenta which corresponds to the analytical results of the petroleum ether extracts.

This paper discusses the applicability of the Flory–Huggins and Vrentas sorption models for studying the sorption behaviour of wood. This theory was originally developed to explain the sorption behaviour of glassy polymers and was further extended to account for hysteresis effects. The model also has the advantage that, in principle, it does not require adjustable parameters for fitting and can be calculated independently of the sorption isotherm data. It was tested against some sorption isotherms and satisfactory fits to the data were obtained for both the absorption and desorption data. The values of the parameters required for satisfactory fitting were realistic, except for the magnitude of the glass transition temperature of water. As far as the authors are aware, this is the first reported study of the use of the Vrentas model to explain sorption and hysteresis in wood.