Ioannis Barboutis

Screw withdrawal capacity used in the eccentric joints of cabinet furniture connectors in particleboard and MDF

Eccentric joints are commonly used to join particleboard and medium-density fiberboard (MDF) in cabinet furniture construction. Screws and screws with plastic sockets are offered by many manufacturers for these kinds of joints, yet little information is available concerning their withdrawal capacity in these materials. Research reported here indicates that face withdrawal strengths of the screws differ slightly from manufacturer to manufacturer in particleboard and MDF, whereas withdrawal strengths of screws with plastic sockets differ greatly from one manufacturer to another. Furthermore, the withdrawal capacity of the screws was found to correlate with the density of both particleboard and MDF.

Utilisation of wood biomass residues from fruit tree branches, evergreen hardwood shrubs and Greek fir wood as raw materials for particleboard production. Part A. Mechanical properties

Abstract This paper investigates the potential of utilising wood biomass from fruit tree branches and evergreen hardwood shrubs as raw materials in the production of particleboards when mixed with Greek fir wood particles. The main mechanical properties of the boards made therefrom were determined and compared with those made of typical industrial wood (IW) particles. The highest modulus of rupture and elasticity (30.0 N/mm2 and 4330 N/mm2, respectively) in bending and screw withdrawal (SW) resistance (127.8 N/mm) were reported for boards made of Greek fir and were downgraded when the fruit tree branches or evergreen hardwood shrub particles also participated. The participation of fruit tree branch particles in proportions higher than 50% improved the internal bond (IB) of fir produced boards, while the highest IB strength (0.95 N/mm2) was reported for boards made of fruit tree branches. Particleboards made of evergreen hardwood shrubs showed inferior mechanical properties compared with those made of IW particles. The latter also showed superior bending strength but inferior SW resistance compared with boards made of fruit tree branches. Hygroscopic and other properties are under determination and will be presented and discussed in the second part of the work.

Response of colour and hygroscopic properties of Scots pine wood to thermal treatment

The effect of heat treatment on the surface colour and hygroscopic properties of pine wood were investigated in this study. Boards of Scots pine wood (Pinus sylvestris L.) were subjected to thermal treatment at 200°C, for 4, 6, and 8 h. The change of equilibrium moisture content and density values of the specimens in order to facilitate the understanding of the treated material behavior. The colour parameters L*, a* and b*, used to depict the total colour change (ΔE) of wood surface, were shown to change proportionally to the treatment intensity. Moreover, swelling in the tangential and radial directions and absorption of the specimens appeared to be enhanced in great extent by the thermal treatment process. The mean value of swelling percentage in the tangential direction decreased 10.26%, 17.22%, and 19.60% for specimens treated for 4, 6, and 8 h, respectively, referring to the final measurement after 72 h of immersion. In radial direction, mean value of swelling percentage decreased 19.56%, 32.75%, and 34.65% for treated for 4, 6 and 8 h, respectively, after 72 h immersion, which attests the decrease in swelling and improvement in the hygroscopic behavior of Scots pine wood.

Finger jointing of green Black pine wood (Pinus nigra L.)

This research work presents a study on the finger jointing of green Black pine wood (Pinus nigra L.) using a phenol resorcinol formaldehyde adhesive. The effect of finger joint orientation (vertical or horizontal fingers) was also examined. In general, the results from the measurements of modulus of rupture and modulus of elasticity of green glued finger-jointed specimens indicated that green gluing of Black pine wood is feasible.

Wood species recognition through multidimensional texture analysis

Abstract Wood recognition is a crucial task for wood sciences and industries, since it leads to the identification of the anatomical features and physical properties of wood. Traditionally, the recognition process relies almost exclusively on human experts, who are based on various characteristics of wood, such as color, structure and texture. However, there are numerous types of wood species in the nature that are difficult to be identified even by experienced scientists. Towards this end, in this paper we propose a novel approach for automated wood species recognition through multidimensional texture analysis. By taking advantage of the fact that static wood images contain periodic spatially-evolving characteristics, we introduce a new spatial descriptor considering each wood image as a collection of multidimensional signals. More specifically, the proposed methodology enables the representation of wood images as concatenated histograms of higher order linear dynamical systems produced by vertical and horizontal image patches. The final classification of images, i.e., histogram representations, into wood species, is performed using a Support Vector Machines (SVM) classifier. For the evaluation of the proposed method, a dataset, namely “WOOD-AUTH”, consisting of more than 4200 wood images (from cross, radial and tangential sections of normal wood structure) of twelve common wood species existing in Greek territory, was created. Experimental results presented in this paper show the great potential of the proposed methodology, which, despite a small number of misclassification cases with regards to both anatomically similar and different species, outperforms a number of state of the art approaches, yielding a classification rate of 91.47% in wood cross sections.

Utilization of wood biomass residues from fruit tree branches, evergreen hardwood shrubs, and Greek fir wood as raw materials for particleboard production. Part B. Hygroscopic properties and formaldehyde content

Abstract This paper investigates the basic hygroscopic properties and formaldehyde content (FC) of particleboards produced with wood biomass from fruit tree branches and evergreen hardwood shrubs as substitute raw materials for fir particles. One-layer laboratory particleboards with two distinct target densities (0.63 g/cm3 and 0.69 g/cm3) were produced using various mixtures of the above materials. Industrially produced wood particles were also used for comparison purposes. The results showed that the replacement of fir wood (FW) by evergreen hardwood material significantly upgraded boards quality in terms of thickness swelling (TS) and water absorption (WA) (except boards with density of 0.63 g/cm3) after immersion in water for 24 h and residual swelling (RS) after reconditioning. The contribution of branch-wood (BW) particles in the production of FW boards with density of 0.63 g/cm3 induced increase of TS, WA, and RS while for boards with density of 0.69 g/cm3 did not result to significant changes except for RS. In terms of FC, boards made of BW and evergreen hardwood showed significantly lower FC compared to those produced by FW and industrial particles.