Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2025Scopus SJRQ2/r/bayburt/13032
  THE EFFECTS OF THERMAL AGING ON COLOR AND GLOSSINESS IN UV CURED COATINGS APPLIED TO SESSILE OAK

  Şahin, Sırrı; Ayata, Ümit; Esteves, Bruno

  Color and glossiness are two important aesthetic properties of wood flooring and wood furniture that significantly affect consumers choice. With time the coating deteriorates altering the surface properties. Un-derstanding these changes is important for furniture industry, impacting design choices, material selection, and long-term maintenance. The effects of thermal aging (30 °C for 30 days, 60 °C for 60 days, and 90 °C for 90 days) on color parameters (C*, L*, b*. a*, ho) and glossiness on both perpendicular () and parallel (║) directions at 20°, 60°, and 85° angles in UV-cured coatings applied on sessile oak were studied. Results show that statistically significant differences were observed in the glossiness values, as well as in C*, b*, a*, L* and ho. As the temperature and duration of the thermal aging process increased, there was a noticeable increase in the values of color parameters b*, a*, and C*, while the values of ho and L* decreased. The characteristics of the surfaces exposed to thermal aging have undergone a complete transformation.

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• MakaleAçık Erişim2024Scopus SJRQ2/r/bayburt/12927
  TOTAL PHENOLICS, TANNIN CONTENTS, ANTIOXIDANT PROPERTIES, PROTEIN AND SENSORY ANALYSIS OF Pleurotus ostreatus, Pleurotus citrinopileatus AND Pleurotus djamor CULTIVATED ON DIFFERENT SAWDUSTS

  Kılıç, Ceyhun; Gürgen, Ayşenur; Yıldız, Sibel; Can, Zehra; Değirmenci, Atiye

  In mushroom cultivation, it is important to be aware of the impact of the growing substrate. This study investigated the cultivation of various oyster mushrooms, including Pleurotus ostreatus, Pleurotus citrinopileatus, and Pleurotus djamor, on different types of wood sawdust. Total phenolic content, condensed tannins, antioxidant activity by ferric reducing antioxidant power assay, protein and sensory evaluations were performed in cultivated oyster mushrooms. Wood sawdust of Fagus orientalis (oriental beech), Alnus glutinosa (alder), Castanea sativa (chestnut), and Juglans regia (walnut) were used as substrate for studied mushroom type, separately. Because champignon (Agaricus bisporus) was the most consumed mushroom, it was used as control sample. Methanolic extracts of dried mushrooms were used to measure bioactive characteristics. Pleurotus ostreatus samples cultivated in Alnus glutinosa (alder) sawdust substrate had the highest antioxidant activity. The lowest antioxidant activity values were found in Pleurotus djamor cultivated in Juglans regia (walnut) wood sawdust substrate. The highest protein content was measured in Agaricus bisporus as 13,84 %. The other highest protein concentration was found in Pleurotus ostreatus cultivated in Alnus glutinosa (alder) sawdust substrate, at 13,75 %. The lowest protein concentration belonged to Pleurotus citrinopileatus cultivated in Fagus orientalis (oriental beech) sawdust substrate as 9,86 %. While Agaricus bisporus and Pleurotus ostreatus had the highest overall appreciation score, Pleurotus citrinopileatus had the lowest. It has been observed that the substrate content has an important impact on chemical and sensory properties of the oyster mushrooms. This study provides knowledge on the chemical and sensory characteristics of three different Pleurotus mushroom species cultivated on different composts.

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  AtıfScopus5·WoS5·OpenAlex5

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• MakaleAçık Erişim2023Scopus SJRQ2/r/bayburt/11891
  EFFECTS OF ARTIFICIAL WEATHERING ON THE SURFACE PROPERTIES OF COATED RADIATA PINE

  Sahin, Sirri; Esteves, Bruno; Can, Ahmet; Sivrikaya, Hüseyin; Domingos, Idalina; Ferreira, José; Ayata, Ümit

  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*, ho*, ΔE*), gloss (perpendicular (⊥) and parallel (//) to the grain at 20°, 60°, and 85° 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 20º and 60º angles while it increased for 85º 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.

  AtıfScopus2·WoS2·OpenAlex2

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• MakaleAçık Erişim2022Scopus SJRQ2/r/bayburt/13562
  EXTRACTIVES IN THERMALLY MODIFIED TROPICAL HARDWOODS

  Esteves, Bruno; Ayata, Umit; Cruz-Lopes, Luísa; Brás, Isabel; Ferreira, José; 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® 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.

  AtıfScopus20·WoS20·OpenAlex16

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