The Use of a Molybdenum Polyoxometalated Compound to Increase the Amount of Extractives from Wood Wastes

The treatment of wood wastes of Castanea sativa L., Quercus frainetto, Larix decidua, and Paulownia tomentosa S. in autoclave in the presence of micrometric crystals of H3PMo12O40 showed an impressive increase of the amount of extractives. The extractives were mainly constituted of insoluble compounds that were analyzed by using gas chromatography-mass spectrometry (GC-MS) after acetylation. The GC-MS analysis of the chloroform soluble fraction of the extractives obtained from sativa showed the presence of methyl hexadecanoate and octadecanoic acid, that of the extractives of frainetto showed the presence of octadecanal and some long chain hydrocarbons. decidua extracts showed the presence of large amounts of sesamin, while the extractives of P tomentosa revealed the presence of 4-hydroxy-3,5-dimethoxybenzaldehyde, 4-hydroxy-3,5-dimethoxycimmanaldehyde, and relevant amounts of long chain hydrocarbons. The insoluble fraction showed the presence of relevant amounts of several carbohydrates and, in the case of C. sativa, of inositol

Steaming effects on selected wood properties of Turkey oak by spectral analysis

Turkey oak (Quercus cerris L.) is characterized by some technological and aesthetical factors limiting its market value from its great potential. In this study, the effect of direct and indirect steaming on reduction in equilibrium moisture content (EMC) and colour variations was evaluated using a hyperspectral radiometer. Steaming treatments were carried out at 80C for 48 h, and 120C for 18 and 24 h, showing a reduction in EMC in the order of 8.1, 28.5 and 13.5, respectively, as well as very significant lightness (L*) and hue (h) modifications in comparison with untreated specimens. The spectral signature analysis confirmed that hydrothermal treatments modify wood sensibility to the light source in the entire spectrum range. The study supports the validity of hydrothermal treatments for improving technological and aesthetical properties of Turkey oak

HIGH CALORIFIC VALUE OF LIGNIN DERIVED FROM TURKEY OAK WOOD: COMBINED EFFECT OF STEAMING AND THERMAL TREATMENT

Turkey oak (Quercus cerris L.) is a deciduous species characterized by high morphological variability and a widespread distribution range along with South-East Europe. The wood of Turkey oak is scarcely considered as industrial lumber and is mainly used as firewood. Biomass pre-processing by heating improves feedstock consistency (mainly loss of water) and thereby improves its energetic efficiency. The main goal of this research was to evaluate how different hydro-thermal treatments affect the high calorific values and the relative ash content of lignin-derived from Turkey oak wood differentially treated by combining temperature, time and steam parameters. Sapwood and heartwood were distinguished for each treatment. Twelve different treatments were performed by using samples randomly selected. Samples were treated in a small heating unit with ± 1 °C accuracy under atmospheric pressure, according to two different heating cycles namely 120 and 180 °C. The Klason lignin content was assessed by a modified TAPPI method. High calorific value (HCV) was calculated by the fire testing technology bomb calorimeter method. Thermal treatment and the steaming processes significantly increased the HCV in examined wood samples. The strongest effect was highlighted when steaming was associated with the highest temperature. The combined effect of steaming and heating was shown to be effective in the process improvement in order to obtain both a higher content of lignin and a corresponding improvement of HCV. Keywords: treatment, high calorific value, lignin

Extraction methods and their influence on yield when extracting thermo-vacuum-modified chestnut wood

Improvements in the yield and solubility of chestnut wood extractives, by using different extraction methods and molybdenum catalysts as support, have rarely been reported in literature. Many studies focus on the different parts of trees, except for the chemical characteristics of the remaining extractives achieved from thermally modified (THM) chestnut (Castanea sativa Mill) wood. This research seeks to better understand the effects of extraction techniques and catalysts on the yield and solubility of extractives. GC-MS analysis of the chloroform soluble and insoluble fractions was also used. Accelerated Solvent Extraction (ASE) 110◦C, Soxhlet, and autoclave extraction techniques were used to obtain extractives from untreated and thermally modified (THM) chestnut wood (170◦C for 3 h). Ethanol/H2O, ethanol/toluene, and water were the solvents used for each technique. A polyoxometalate compound (H3PMo12O40 ) and MoO3 supported on silica were used as catalysts. The THM induced a change in the wood’s surface color (∆E = 21.5) and an increase in mass loss (5.9%), while the equilibrium moisture content (EMC) was reduced by 17.4% compared to the control wood. The yields of the extractives and their solubility were always higher in THM and mainly used ASE as the technique. GC-MS analysis of the extractives, without catalyst support, showed different results for each extraction technique and type of wood (untreated and THM). Ultimately, the amount of extractive compound dissolved in each solvent will differ, and the choice of extraction technique will depend on the intended final application of the extracted chemical product

Physico-Mechanical Properties of Thermally Treated Poplar OSB

Oriented strand board (OSB) are widely marketed for several applications, from building to packaging. The manufacturing of poplar OSB has recently started in Northern Italy, representing a relevant innovation in the sector, given that this product is usually made of coniferous wood. Thermal treatment is nowadays widely used for increasing the dimensional stability and the durability of wood. The drawback is, however, that the mechanical performance of the treated wood product is reduced. The objective of this research was to analyze the effect of thermo-vacuum treatment on the characteristics of poplar OSB. To this purpose, boards 15 mm thick and with a density of 590 kg/m3 were drawn from the standard production of the manufacturer and thermally treated under vacuum conditions at 190 °C for 2 h. Their mass loss, bending strength, modulus of elasticity, internal bond and swelling were determined. In addition, color change and wettability were studied before and after a weathering test. The thermal treatment significantly changed the properties of poplar OSB. The mass, the bending strength, the modulus of elasticity and the internal bond decreased with different intensities. The swelling after immersion in water decreased. The color switched toward a darker tone and the wettability decreased. After an accelerated weathering test (AWT), the color lightened, and the wettability increased. Overall, this study broadened the knowledge about the thermal treatment of this wood-based panel, which could enable new applications with particular attention to non-structural uses in humid conditions

Influence of thermo-vacuum treatment on thermal degradation of various wood species

Solid wood has a certain amount of resistance to fire exposure. Recently, there is also great interest in characterization of the thermal behaviour of treated wood due to increasing demand of such products within the perspective of sustainability of environment. The objective of this study was to evaluate and predict the thermal decomposition process of samples from different wood species, Norway spruce (Picea abies Karst.), common ash (Fraxinus excelsior L.) and Turkey oak (Quercus cerris L.), so that such data can be used for enhanced design of wood products for more effective and better utilization in different applications. Spruce and ash samples were treated at a temperature of 190 °C for 2 h while Turkey oak specimens were steamed at a temperature of 110 °C for 24 h before they were thermally treated at a temperature of 160 °C for 3 h. A thermo-gravimetric analysis of the samples highlighted intraspecific differences in mass loss and the stage of thermal degradation between treated and untreated specimens. The degradation of the wood was characterized by twofold reaction stages, with an exception of Norway spruce samples, which exhibited a one-stage reaction. In addition, thermal treatments affected chemical composition of wood. The obtained results will be helpful in determining the applicability of these materials according to their thermal degradation properties

LA TECNICA XPS: UN SUPPORTO ALLE ANALISI DELLE SUPERFICI LEGNOSE. IL CASO DEL LEGNO DI CERRO SOTTOPOSTO A RAGGI UV-C

L’analisi XPS (X-ray Photoelectron Spectroscopy) unitamente ad altre tecniche di spettroscopia, come l’IR a trasformata di Fourier (FTIR), consente di verificare il cambiamento nella composizione chimica dei campioni in esame. In particolare, la spettroscopia fotoelettronica a raggi X permette di sondare la superficie dei materiali, comprendere le modifiche chimiche su di essa avvenute, individuare gli elementi chimici che la compongono e, inoltre, il loro stato di ossidazione. Il trattamento con raggi UV è uno dei metodi utilizzato per riprodurre in laboratorio gli effetti di lungo termine che si hanno sulla superficie del materiale legnoso a seguito dell’esposizione solare. Lo scopo di questo studio è stato quello di produrre artificialmente, con l’ausilio di una lampada UV-C, gli effetti che le radiazioni UV hanno sul legno di cerro (Quercus cerris L.) e di valutare gli eventuali cambiamenti a livello chimico con l’uso della tecnica XPS. L’analisi dei risultati indica che la radiazione UV-C causa cambiamenti irreversibili nella composizione chimica dei campioni legnosi attraverso fenomeni di foto-ossidazione e fotodegradazione

Teams in Small Technology-Based Firms: The Roles of Diversity and Conflict Management

This paper explores the effect of diversity and conflict management on the relationship between teamwork and organizational outcomes of small technology-based firms. To study the relationship between those variables, a quantitative research was conducted. The results of the survey involving 107 small Brazilian high-tech firms show that diversity and conflict management positively moderate the relationship between teamwork and organizational outcomes. So that, at higher levels of diversity and conflict management, best organizational outcomes. At the same time, it has been verified that conflict management is important regardless the level of diversity within teams. This research sheds new light on the factors that should be considered to become teamwork more effective in this specific context