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In the previous years, black locust wood (Robinia pseudoacacia) has been participating in the European subsidizing programme of tree species cultivation, aiming in the establishing of new plantations in many European countries, therefore large quantities of this species is going to be harvested in the forthcoming years and the examination of its properties would be very crucial for future utilization. In the present research, the bondability of black locust wood is examined using two different adhesives, Polyvinyl acetate and Polyurethane and two different pressure levels. Beech wood is also included in the research for comparative reasons. According to the results, the shear bond strength of black locust wood was found to be satisfying, especially in the presence of Polyvinyl acetate adhesive and the less intensive pressure used during the specimens’ construction, although it was found lower compared to beech wood, referring both to Polyvinyl acetate and Polyurethane adhesive.

This paper presents the recording and study results of the post-Byzantine wood carved iconostases of Sikinos, a small island of the Cyclades, which has preserved to a considerable extent its traditional characteristics. The island has 13 churches containing old hand-crafted wood carved iconostases. The most remarkable ones are dated from the late 17th to the late 18th century, have limited dimensions due to the small size of the churches and present a three-zone horizontal structure with two arched openings, three base panels and three Despotic icons constructed with wood planks, while they do not include the row with the Apostles in the upper zone. They are carved in high relief and their coronation is impressive, with a big cross and dragons. In addition, they are made mainly of softwood species without resin canals. These structures are being gradually decomposed by decay and wood-destroying insects, as the protection attempts were limited only to the declaration of the buildings as historical monuments and did not concern at all the interior wood carvings, mainly due to the reduced acknowledgement that wood is one of the most significant parts of the cultural heritage in contrast with the much more rich and impressive ancient Greek findings. [ABSTRACT FROM AUTHOR]

Humans recognized the value of wood and used it in a variety of applications from the early years of their appearance on earth. Because of its biological composition, wood is easily destroyed and therefore, the discovery of wooden archaeological findings seem to be very limited, compared to the respective findings of inorganic materials, such as gold, marble, etc. During the archaeological excavations for the construction of a Metro station, in the center of Piraeus (Greece), almost a whole leaf of a wooden double door of a Hellenistic house was found in a well, which was destroyed by the Roman invaders in 86 BC., when they captured and burned the city and consequently, the materials coming from the demolition of the houses were thrown into the wells and tanks of the city. The abovementioned wooden finding was examined, as long as its current state allows, in order we to determine the quality of the timber used, the manufacturing-processing technology and the connections/joints techniques applied, to assess the level of knowledge and of the available processing equipment. [ABSTRACT FROM AUTHOR]

The aim of the present research is to comprehend the response of poplar (Populus sp.) and pine (Pinus nigra L.) wood to thermal modification at the temperature of 180°C and 200°C, for 3 different treatment durations of 3, 5 and 7 hours, in the presence of air, by examining their physical and hygroscopic properties and comparing these species properties one another. Specifically, in this research, the mass loss of the samples due to the treatment, the density, the equilibrium moisture content (EMC) and the hygroscopic properties (radial, tangential and longitudinal swelling and absorption percentages) were examined. As the treatment intensity increased, the mass loss of pine and poplar boards due to treatment also increased, which corresponds to the loss of moisture, and the chemical constituents of wood due to their degradation (evaporation of volatile extracts, loss of products through thermal degradation etc.). The thermal treatment has led to a reduction in the recovery rate of the pine and poplar plates of their original weight due to reduced moisture recovery, which is more pronounced as the treatment temperature and duration increase. The EMC of all heat-treated pine and poplar samples was reduced compared to the corresponding control value, even in the case of the less intensive treatment (180°C-3h) and as the intensity increased, EMC decreased further (20.73%-38.43% for pine and 18.76%-49.20% for poplar). Thermal treatments reduced the density of pine (0.76-20.24%) and poplar (1.04-24.42%), and as the treatment intensity increased, larger reduction was recorded. The hygroscopic properties of heat-treated pine were improved in every case due to thermal treatments. The most intensive treatment tended to slightly increase the adsorption and radial-tangential swelling rates, without approaching the control levels. Referring to poplar, all treatments, even the less intensive ones, improved the hygroscopic nature of wood, reducing the adsorption and tangential-radial swelling rates compared to the control sample. Therefore, confirming the results of literature, the thermal treatment was found to improve the hygroscopic behavior of pine and poplar and to further reduce tangential swelling levels in relation to radial direction, contributing to the limitation of wood anisotropy. [ABSTRACT FROM AUTHOR]

In recent years, there seems to be a significant increase of the cases of scientific fraud that are revealed in many scientific fields and in almost all the developed countries. In the specific work, an attempt is being made to present cases of serious evidence of research fraud in the field of wood science, in order to assist editors and reviewers in formulating appropriate quality principles to more effectively distinguish true research from false research. It is very difficult to determine if a research work is based on real experimental data, especially if there are not available basic information about the experiment carried out (place, laboratory, evidence of specimens or materials used etc.) and the respective authors (academic studies, scientific background, scientific cooperations etc.), and if there is no the contribution of all the scientists to this direction. The lack of specific information could lead the editors to accept an impressive fake investigation as real one and to encourage in that way, an increase in the number of such papers published. Offering the opportunity to be included in a publication as a co-author of someone that had not active participation in the research work should be always a matter of great concern, because it may conceal serious irregularities, fraud or even suspicious expectation of rewards in the future. [ABSTRACT FROM AUTHOR]

The wood of poplar (Populous sp.) species seem to be of low quality, mechanical resistance and is susceptible to microorganisms attacks, therefore, the application of thermal treatment is necessary, in order to improve some of its properties and increase its duration. Thermal modification of poplar (Populous sp.) wood was implemented at 180oC and 200oC, for 3, 5 and 7 hours in the presence of air and some of the most crucial mechanical properties were investigated. As the intensity of heat treatment increases, the mass loss of poplar boards is increased, attributed to moisture loss and the degradation and loss of chemical wood components. The bending strength decreased (2.05%-44.65%) compared to control, due to the treatments, while the elasticity decreased in all the treatment categories (5.66%-24.86%). The tangential hardness of poplar modified at 180oC for 3 and 5 hours, decreased by 10.24% and 14.59%, respectively and at 7 hours it grew by 2.35%, while at 200oC a decrease of 17.04-26.05% was recorded. The radial hardness decreased (2.81%-11.06%) at 180oC (3 and 5 hours) and when the duration reached 7h, it increased (9.28%), while at the treatments of 200oC radial hardness decreased (2.68%-18.86%). All the treatments reduced the impact bending strength of poplar specimens (24.27%-62.02%), even though they raised the resistance levels to compressive forces. Only the milder treatment achieved to decrease the roughness of poplar wood surface, while increasing further the treatment intensity, the degree of roughness showed a strong increase. [ABSTRACT FROM AUTHOR]

The variations of wood density and annual ring width were examined on different heights of beech trees. In total, 25 stem discs were collected from 5 beech trees, at 1,3m, 5m, 9m, 13m and 17m height from base of the tree. The wood density and ring width measurements were carried out via high frequency densitometry method, using the Lignostation system. The wood density showed variation within beech trees at different growth heights. There was a tendency for reduction of wood density with tree height, but this did not occur in all beech trees. The annual ring width varied within beech trees. In some beech trees, it gradually increased from the top of the tree to a maximum of around 9 m and then reduced to the base. The wood density showed a small variation between beech trees. There were not significant differences on the ring width of stem discs, between 4 beech trees, while the ring width of a beech tree was found to be the highest on every stem height. The results from this study suggest that the HF densitometry method is a promising technique to assess wood density and ring width. This method provides the variation of density and analyzes the ring width, within and in-between trees of the same species. [ABSTRACT FROM AUTHOR]

In this research, thermal modification of black pine (Pinus nigra L.) wood was conducted at 180 and 200°C, for 3-7 hours and some essential mechanical properties, such as modulus of rupture (MOR), modulus of elasticity (MOE), impact bending strength, compression strength, hardness in tangential and radial direction and surface roughness, were examined. It was observed that, as the intensity of treatment increases, the equilibrium moisture content and density of modified wood tend to decrease. The treatments of 180°C resulted in an improvement of bending strength, while treatments of 200°C caused a decrease. MOE of treated specimens increased regardless the duration or temperature. The treatments of 180°C increased the hardness, while at 200°C this improvement was limited to smaller increase and a reduction in subsequent treatments. Treatments of 180°C appeared to improve the impact bending strength, compared to control, while the treatments of 200°C demonstrated a strength decrease. Additionally, all the treatments improved the compression strength of pine, and referring to surface roughness, only the milder treatment managed to decrease it. [ABSTRACT FROM AUTHOR]

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/cm3and 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 board's 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/cm3induced increase of TS, WA, and RS while for boards with density of 0.69 g/cm3did 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. [ABSTRACT FROM PUBLISHER]

The present study evaluated the effects of heat treatment at 180°C and 200°C for 3, 5 and 7 in the presence of air in an oven, on the mechanical properties and withdrawal resistance of two different types of nails for Greek fir wood (Abies Borissi - regis Mattf.). Static bending properties (MOR and MOE), impact bending strength, compression strength parallel to the grain, and hardness (Janka) in radial and tangential directions were examined. The results showed that the highest mean value of MOR was 81.77N/mm² for untreated wood in contrast to the lowest of about 57.89N/mm² at 7h at 200°C. MOE was higher at 3h and 5h for 180°C treatment conditions with increases of 0.71% and 1.79%, respectively. Hardness in radial and tangential directions decreased the most, 38.81%, for 7h at 200°C. Impact bending strength had a significant decrease of 44.09% after the extreme treatment of 7h at 200°C comparated to untreated samples. Finally, the withdraw al resistance of both types of nails decreased beyond 3h at 180°C but the resistance of helically-threaded nails decreased more for treatments beyond 3h at 200°C. [ABSTRACT FROM AUTHOR]

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/mm2and 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. [ABSTRACT FROM PUBLISHER]

In this study the effects of thermal modification of beech wood (Fagus sylvatica) on color changes after heat treatment were determined. The heat treatment of beech wood was conducted in a temperature of 180°C and 200°C for five different durations ranging from 2 to 10h. It was observed a gradual color change of treated samples whereas after 4h treatment no significant changes were recorded, measured with a colorimeter. The greatest reduction of lightness indicator L* was observed between 2 and 4 hours whereas the most intense color differences compare to untreated samples were occurred in 8h and 10h treatments. Comparing the two treatment conditions there is an obvious colour difference. Moreover, at 4h treatments time the differences were approximately 27.92 units more. Finally, radial direction gave higher values regarding lightness and longitudinal the lowest. [ABSTRACT FROM AUTHOR]

Boards of poplar wood were subjected to thermal treatment at 180°C and 200°C, for durations of 2, 4, 6, 8 and 10 hours, in order to investigate the effect of heat treatment on the hygroscopic properties. Specifically, the change of equilibrium moisture content, density, swelling and absorption of wood were examined, in order to determine the significance of treatment temperature and duration in the enhancement of wood hygroscopicity. Generally, swelling in tangential direction proved to be quite higher than swelling in radial direction, while thermal treatment enhanced in great extent swelling in tangential and radial direction and the absorption of the specimens as well. Swelling in tangential direction decreased within the range of 8.17% and 33.3% for specimens treated at 180°C and the range of 43.85% and 65.09% for specimens treated at 200°C for 2-10 hours, referring to the final measurement after 72 hours of water immersion. In radial direction, the swelling decrease ranged between 2.47% and 28.45% for specimens treated at 180°C and between 19.62% and 60.87% for specimens treated at 200°C for 2-10 hours, respectively, after 72 hours immersion. Most of the heat treatments resulted also in absorption decrease, attesting the improvement of the poplar wood hygroscopic behavior. Finally, as it was proved, the higher the treatment temperature that is applied, the shorter is the duration, needed for the same swelling and absorption decrease level to be achieved. [ABSTRACT FROM AUTHOR]

Thermal treatment of wood is normally used as a non toxic, environmentally friendly practice to improve some of its natural properties. Lime wood (Tilia cordata) is characterized by relatively low durability and dimensional stability. These factors restrict its applications essentially. In this work, the effects of the short time thermal treatment on some physical and mechanical properties of lime wood were investigated. Samples were thermally treated at 180° C, 200° C and 220° C for two different short time periods of 15 and 30 min, respectively. The following properties were studied: density, variation of dimensional stability after immersion in water, static bending strength (MOR and MOE), impact bending strength, compression strength parallel to the grain, and hardness in radial and tangential direction. The results of both treated and untreated samples were given, for comparative purposes. [ABSTRACT FROM AUTHOR]

Tratamentul termic al lemnului este folosit în mod normal ca un procedeu netoxic şi ecologic pentru a îmbunătăţii unele din proprietăăţile naturale ale acestuia. Lemnul de tei (Tilia cordata) este caracterizat prin durabilitate şi stabilitate dimensională relativ scăzute. Aceşti factori restricţionează esenţial aplicaţiile acestuia. În această lucrare sunt investigate efectele tratamentului termic de scurtă durată asupra unor proprietăţi fizice şi mecanice ale lemnului de tei. Epruvetele au fost tratate termic la 180° C, 200° C şi 220° C timp de 15 şi respectiv 30 minute, după care au fost studiate următoarele proprietăţi: densitatea, modificarea stabilităţii dimensionale după imersia în apă, rezistenţa la încovoiere statica si modulul de elasticitate, rezistenţa la încovoiere dinamică (la şoc), rezistenţa la compresiune paralelă cu fibrele şi duritatea în direcţiile radială şi tangenţială. Rezultatele sunt prezentate comparativ pentru eşantioanele tratate şi respectiv netratate. [ABSTRACT FROM AUTHOR]

Different insert fittings (screws, plastic and metallic sockets, plastic and metallic cam fittings single and double) are widely used in ready-to-assemble cabinet furniture joints, connecting particleboard and MDF. The holding strength of insert fittings and the bending strength of the corresponding furniture corner joints constructed with the same fittings were studied. The insert fittings which are offered by four (4) manufacturers (Hettich, Häfele, Lama and one of no name) were studied. Research reported here indicated that bending strength values of furniture corner joints constructed with insert fittings strongly correlated to the face holding strength of the corresponding insert fittings (bending strength is almost equal to holding strength multiplied by 10). Based on these results, it is concluded that the bending strength value of a corner joint constructed with insert fitting could be sufficiently estimated by the measured holding strength value of the corresponding insert fitting. [ABSTRACT FROM AUTHOR]

Diverse accesorii de prindere (bolțuri, bucşe şi came simple şi duble din plastic şi metalice) sunt utilizate într-o gamă largă pentru îmbinările demontabile ale pieselor de mobilier realizate din PAL şi MDF. Au fost studiate forța de strângere a accesoriilor de prindere şi forța de încovoiere a îmbinărilor de colț corespunzătoare ale mobilierului, realizate cu aceeaşi feronerie. Au fost utilizate pentru studiu accesoriile metalice oferite de patru (4) producători (Hettich, Häfele, Lama şi unul necunoscut). Cercetarea prezentată în această lucrare a arătat faptul că valorile forței de încovoiere a îmbinărilor de colț ale mobilierului construite cu accesoriile metalice de prindere se corelează cu forța de strângere a acestora (forța de încovoiere este aproape de 10 ori mai mare decât forța de strângere). Pe baza acestor rezultate se concluzionează faptul că valoarea forței de încovoiere a îmbinărilor de colț realizate cu accesoriile metalice de prindere ar fi estimată suficient de bine prin măsurarea forței de strângere a feroneriei corespunzătoare. [ABSTRACT FROM AUTHOR]

Forest biomass originating from Mediterranean forest vegetation could be a potential source of renewable energy in the form of pellets, butdue to its diversity there is a need for better understanding and detailed examination of its main fuel characteristics. The aim of this work was the evaluation of the impact that bark percentage and barked stem diameter have on the ash content and heating value of thefollowing evergreen Mediterranean hardwood species: Arbutus unedo, Erica arborea, Quercus coccifera, Quercus ilex and Phillyrea latifolia. For all the above species, the barked diameter, bark thickness, bark percentage as well as the ash content and higher heating value of bark and wood have been determined. In all cases the ash content of bark was higher than that of wood and also higher than the requirement of the related EN standard. Therefore the bark of tested species could be used in the production of pellets provided that its ratio would be in a level corresponding to the maximum allowed ash content values. Taking into account the results of the determinations, the equations and graphs were used in order to calculate the minimum of the stem diameter requirements in order to meet with the ash content restrictions. The effect of stem diameter on the HHV (higher heating value) was also evaluated. Among the tested species, Erica arborea proved to be the most appropriate for the production of pellets showing the highest HHV and the lowest ash content. [ABSTRACT FROM AUTHOR]