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    Calorific Power Improvement of Wood by Heat Treatment and Its Relation to Chemical Composition
    (Mdpi, 2020) Domingos, Idalina; Ayata, Umit; Ferreira, Jose; Cruz-Lopes, Luisa; Sen, Ali; Sahin, Sirri; Esteves, Bruno
    Chemical composition influences the calorific power of wood, mainly due to the calorific power of structural compounds and extractives. Heat treatment changes the chemical composition of treated wood. This work studies the relationship between chemical composition and calorific power improvement by heat treatment. Samples were heat-treated by the ThermoWood process for 1 h and 2 h. High heating value (HHV) and chemical composition; lignin, cellulose, hemicelluloses and extractives in dichloromethane, ethanol, and water were determined. The HHV of untreated wood ranged between 18.54-19.92 MJ/kg and increased with heat treatment for all the tested species. A positive linear correlation was found between HHV and Klason lignin (R-2 = 0.60). A negative trend was observed for holocellulose, cellulose, and hemicelluloses content against HHV, but with low determination coefficients for linear regression. The best adjust for polysaccharides was found for hemicelluloses content. A positive correlation could be found for dichloromethane extractives (R-2 = 0.04). The same was obtained in relation to ethanol extractives with R-2 = 0.20. For water and total extractives, no clear positive or negative trends could be achieved. The results showed that the HHV of wood increased with heat treatment and that this increase was mainly due to the increase in lignin content.
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    CHANGES IN THE CONTENT AND COMPOSITION OF THE EXTRACTIVES IN THERMALLY MODIFIED TROPICAL HARDWOODS
    (Univ Bio-Bio, 2022) Esteves, Bruno; Ayata, Umit; Cruz-Lopes, Luisa; Bras, Isabel; Ferreira, Jose; Domingos, Idalina
    Chemical composition of wood is known to change during thermal treatments. Two species grown in Turkey, afrormosia (Pericopsis elata) and duka (Tapirira guianensis) were heat treated according to Thermowood (R) method. Lignin, cellulose, hemicelluloses and extractives in dichloromethane, ethanol and water were determined. Wood extracts were analysed by gas chromatography with mass detection and existing compounds were identified by NIST17 database. Results show that hemicelluloses and cellulose content decreased for both heat-treated woods along the treatment while lignin percentage increased. The analysis of extractives has shown several compounds normally associated to lignin thermal degradation that increased along the treatment. At the same time several compounds associated to carbohydrate thermal degradation were found in all the extracts for both heat-treated woods. These founding have allowed the understanding of the degradation pattern of wood during thermal modification. There was not much difference between afrormosia and duka woods structural compounds behaviour along thermal modification. However, the variation of the amount of extractives along the treatment depended on the species.
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    EFFECT OF ACCELERATED AGEING ON SOME SURFACE PROPERTIES OF UV-COATED HACKBERRY (Celtis australis L.) WOOD PARQUET
    (Inst Technol Drewna, 2021) Ayata, Umit; Esteves, Bruno; Gurleyen, Levent; Cakicier, Nevzat; Ferreira, Jose; Domingos, Idalina; Turk, Mutlu
    The importance of UV-curable coatings is currently increasing. In the parquet industry, where UV systems are applied, it is beneficial to investigate new tree species as potential raw materials. This study was carried out to determine the effect of accelerated ageing on some surface properties of hackberry (Celtis australis L.) wood treated with UV system parquet varnish. UV system parquet varnishes were applied to hackberry wood surfaces in three and five layers, according to the requirements of industrial applications. The varnished surfaces were then exposed to UV rays for 252 and 504 h using UVA-340 lamps in a QUV ageing device. Glossiness, colour parameters, pendulum hardness and adhesion strength (pull-off) (MPa) were determined for the coated samples before and after ageing, and the results for the aged and unaged test samples were compared. Analysis of variance showed that the results were significant for all tests. The results for all tests varied by ageing time.
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    Effect of Heat Treatment on Shore-D Hardness of Some Wood Species
    (North Carolina State Univ Dept Wood & Paper Sci, 2021) Esteves, Bruno; Sahin, Sirri; Ayata, Umit; Domingos, Idalina; Ferreira, Jose; Gurleyen, Levent
    Hardness is an important wood property for several applications. Typically, it is necessary to use traditional methods, such as a universal test machine, to determine a wood's hardness value. This work reports the hardness of some wood species before and after heat treatment (ThermoWood method) using the Shore-D hardness method. The Shore-D hardness value of untreated wood ranged between 35.3 for Limba wood and 77.2 for Santos wood. With heat treatment, hardness decreased, and the decrease was greater for samples that underwent harsher treatment (2 h at 212 degrees C). The decrease of hardness was highest for Sipo wood (14%) and the lowest for Afrormosia wood (2.5%). Analysis of variance tests showed that there was a significant difference between wood species, heat treatment, and the interaction between both variables at the chosen level of significance (P <= 0.05). Results showed that Shore-D hardness could be used to measure hardness directly in a production line or in small wood companies without using a universal test machine.
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    EFFECTS OF ARTIFICIAL WEATHERING ON THE SURFACE PROPERTIES OF COATED RADIATA PINE
    (Univ Bio-Bio, 2023) Sahin, Sirri; Esteves, Bruno; Can, Ahmet; Sivrikaya, Huseyin; Domingos, Idalina; Ferreira, Jose; Ayata, Umit
    Radiata pine boards were coated with two different methods A and B both beginning with a hydro primer and finishing with a mat oil but method A using an acrylic high gloss coating and method B three layers of an acrylic sealer in between. The samples were subjected to aging processes for 144 h, 288 h, and 432 h by using UV-A 340 nm lamps. The CIE L*a*b* and CIE L*C*H* coordinates were determined (L*, a*, b*, C*, h(o)*, Delta E*), gloss (perpendicular (perpendicular to) and parallel (//) to the grain at 20 degrees, 60 degrees, and 85 degrees angles) and surface adhesion strength via the pull-off method were tested before and after weathering. Results have shown that lightness (L*), decreases with weathering for both varnish applications with a higher decrease for the B coating system. Redness increased for both applications with no significant differences. At the same time there was a yellowing of the samples along the weathering period. Parallel and perpendicular gloss decreased for 20 degrees and 60 degrees angles while it increased for 85 degrees angle. The adhesion strength of method A was higher and its decrease with weathering was smaller than for method B. Both varnish applications have proven to confer some protection against wood discoloration, but method A showed the best results and is therefore the best method to be used by radiata pine.
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    Investigation of Use of Linden (Tilia tomentosa Moench.) Wood with UV System Varnish Application IN INDOOR Parquet Flooring
    (Inst Technol Drewna, 2023) Ayata, Umit; Esteves, Bruno; Domingos, Idalina; Ferreira, Jose; Efe, Fatih Tuncay; Turk, Mutlu; Cakicier, Nevzat
    Linden wood is used in the making of musical instruments, agricultural hand tools, and in the furniture sector. In this study, the changes in glossiness (parallel (//) and perpendicular (perpendicular to) to the fibers at 20o, 60o, and 85o), the pull -off adhesion test, color parameters (CIEL) and pendulum hardness (K & ouml;nig method) of two different UV curable varnishes applied to linden (Tilia tomentosa Moench.) according to industrial application techniques and exposed to artificial weathering were investigated. According to the research results, while L*, Delta H*, and ho decreased with increasing weathering time in both varnish layers, Delta C*, b*, Delta E*, a*, and C* rose. The pendulum hardness grew for Method B but dwindled for Method A. A decrease was found in the adhesion tests for both varnish methods after artificial weathering. The glossiness was generally reduced due to artificial weathering for all the angles and for both directions, with the exception of 85 degrees in Method A. The variance analysis and homogeneity groups showed that the changes in the adhesion, pendulum hardness, L*, a*, ho, C*, perpendicular and parallel to the fibers for 60o and 85o were found to be significantly different with artificial weathering for both methods.
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    Land Use Impact of Maritime Pine and Eucalypt: A Life Cycle Assessment Study
    (North Carolina State Univ Dept Wood & Paper Sci, 2021) Ferreira, Jose; Esteves, Bruno; Ayata, Umit; Cruz-Lopes, Luisa; Domingos, Idalina
    The forestry sector faces important challenges worldwide in the climate change scenario. The major challenges are the sustainability of forest resources and the conservation of biological diversity. Due to climate change, an increase in the incidence of fires and the action of pathogens has been observed in recent years. The forestry sector in Portugal has a high economic, social, and environmental value. In economic 'Willis, in 2015, its gross value added (GVA) represented more than 10 billion euros, corresponding to 13% of industrial GVA and 3% of national gross domestic ABSTRACT The forestry sector in Portugal faces important challenges, resulting in an increased incidence of fires and the action of pathogens, which puts the sustainability of forest resources at risk. Due to the economic, social, and environmental importance of forests, this work assessed the land use environmental impact of maritime pine and eucalypt standing in Portuguese forests. SimaPro software was used to translate the inventory table results into land use impact category. The ILCD 2011 Midpoint+ method was chosen to assess the land use environmental impact that focuses on soil quality and its indicator (kg carbon deficit), which describes the changes in soil organic matter associated with land interventions. The results showed that for the first rotation time, the land use impact category per cubic meter of maritime pine is 18423 kg C deficit and 23430 kg C deficit for eucalypt, which means that the land use impact category of eucalypt is 27% higher than the impact of maritime pine.