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• MakaleAçık Erişim2026Scopus SJRQ3/r/bayburt/12773
  Analysis of the Impact of Blue Stain on the Color, Glossiness, and Whiteness Properties of Scots Pine Lumber

  Ayata, Ümit; Peker, Hüseyin; Ulay, Göksel; Çamlıbel, Osman; Atilgan, Abdi

  It is known that blue stain causes a loss of price value for Scots pine wood in the wood trade due to the visual defects it creates. In this study, color parameters [red color tone (a*), lightness (L*) value, yellow (b*) color tone, tone angle (h°) value, and chroma (C*) value], whiteness index (WI*) values, and glossiness measurements [at angles of 20°, 60°, and 85°] were compared in Scots pine (Pinus sylvestris L.) wood with normal and blue rot conditions. According to the color parameters obtained, it was determined that the L* value decreased by 11.43%, a* by 79.95%, b* by 28.86%, and C* by 32.75%, while the h° value increased by 17.74%. With the blue coloration, decreases were observed in the 20° glossiness values measured in the ⃦ and ⊥ directions, while increases were observed in the 60° and 85° glossiness values measured in the ⃦ and ⊥ directions. With the blue coloration, decreases of 12.86% in the ⊥ direction and 29.87% in the ⃦ direction in the WI* values were observed. According to these results, it was determined that the wood material with the blue coloration disease had a darker color.

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• MakaleAçık Erişim2026Scopus SJRQ3/r/bayburt/12634
  Effects of Different Adhesive Ratios on Selected Panel Properties of High-Density Fiberboard (HDF) Produced from Fir and Beech Chips

  Çamlıbel, Osman; Ayata, Ümit

  High-density fiberboard (HDF) has been utilized in various forest-based industries for centuries. This study investigated the effects of different adhesive ratios on the properties of HDF through a series of tests. The panels, designed in particular for this study, had been produced in a laboratory putting the usage of a combination of 70% fir (Abies nordmanniana subsp. bornmulleriana) and 30% beech (Fagus orientalis L.) fibers sourced from the western Black Sea area of Turkey. Two adhesive levels were tested: 10.73% for panel I and 11.30% for panel II, both calculated based on dry fiber weight. We assessed several physical and mechanical properties, including density, modulus of rupture (MOR), modulus of elasticity (MOE), internal bonding (IB), hardness, water absorption, and through-thickness swell, in accordance with standard testing methods. The results indicated that both adhesive levels produced panels meeting the general performance requirements for HDF. Panel II, which contained slightly more adhesive, demonstrated marginally better performance in specific strength and dimensional stability tests. Overall, the findings suggest that optimizing adhesive usage in industrial HDF production can help establish a balance between the performance requirements of the boards and cost-effectiveness in production.

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• MakaleYalnız künye2026Scopus SJRQ2/r/bayburt/11460
  Weathering effects on pendulum hardness, and pull-off adhesion testing of water-based varnish on thermally treated iroko wood

  Ulay, Göksel; Akter, Mete; Çakıcıer, Nevzat; Ayata, Ümit

  This study evaluated the effects of different weathering durations (168, 336, and 504 h) on surface hardness and adhesion strength of both heat-treated (1.5 h at 190 °C and 2 h at 212 °C) and untreated iroko (Chlorophora excelsa) wood surfaces after application of water-based varnish (WBV). Pendulum hardness (s) and pull-off adhesion (MPa) tests were performed after weathering. According to the results, in the untreated control group, hardness increased from 30 s to 45 s after 504 h of weathering, showing a 48% increase. In the samples treated at 190 °C, hardness increased from 25 s to 41 s after 504 h, showing a 61% increase. The highest increase was observed in the samples treated at 212 °C. Here, the hardness increased from 23 s to 44 s, representing a 91% increase after 504 h of weathering. The highest initial surface adhesion strength (5.30 MPa) was obtained in the unheated samples; however, this value decreased significantly after weathering. Although the initial adhesion strength was lower in the heat-treated samples, those treated at 212 °C for 2 h exhibited more stable weathering performance. The results show that the acceleration of weathering and the application of heat significantly affect the effectiveness of the varnish coating.

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• MakaleAçık Erişim2026Scopus SJRQ3/r/bayburt/11400
  Effects of Various Bleaching Chemicals on Some Surface Properties of Ebony Species (African, Black, and Macassar)

  Ayata, Ümit

  The concept of color is not always suitable for some trees according to customers’ preferences. The color of the wooden material changes with processes such as heat treatment, impregnation, bleaching, etc. When the color of the wooden material changes, the surface also undergoes changes in its inherent properties. African ebony (Diospyros crassiflora Hiern.), black ebony (Diospyros ebenum), and Macassar ebony (Diospyros celebica Bakh.) wood species were treated using a single-component bleaching chemical [oxalic acid (C2H2O4)] and double component bleaching chemical [hydrogen peroxide (H2O2) + sodium hydroxide (NaOH)] using a brushing technique. Subsequently, the characteristics of the changes that occurred were determined, including color parameters and whiteness index (WI*) values. The wood species exhibited different behaviors (increases and decreases specific to each test) in response to both bleaching agents. There was an observed increase in the a*, b* and C* values, while the ho values decreased for all wood species. Furthermore, WI* values in directions perpendicular and parallel to the fibers were reduced in all wood species by oxalic acid treatment.

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• MakaleYalnız künye2026Scopus SJRQ4/r/bayburt/11288
  SURFACE ROUGHNESS AND SHORE-D HARDNESS OF SIX TROPICAL HARDWOODS; [RUGOSIDADE DA SUPERFÍCIE E DUREZA SHORE-D DE SEIS MADEIRAS TROPICAIS]; [RUGOSIDAD SUPERFICIAL Y DUREZA SHORE-D DE SEIS MADERAS TROPICALES]

  Ayata, Umit; Domingos, Idalina; Ferreira, José; Cruz-Lopes, Luísa; Esteves, Bruno

  Introduction: This study investigates the Shore-D hardness and surface roughness characteristics of six tropical wood species: Canelo (Nectandra spp.), Limbali (Gibertiodendron dewevrei), Difou (Morus mesozygia), Curupay (Anadenanthera macrocarpa), Ebiara (Berlinia bracteosa), and Zwarte kabbes (Diplotropis martiusii), aiming to assess their suitability for high-performance applications. Objective: To evaluate how wood species and sanding processes influence the mechanical properties and surface quality of selected tropical woods. Methods: Samples were conditioned and sanded using abrasives of different grit sizes (80, 100, 120, 150, and 180). Surface roughness parameters Ra, Rq, and Rz, as well as Shore-D hardness, were measured. Statistical analyses were performed using ANOVA and Duncan’s test. Results: Statistical analysis revealed that abrasive grit size significantly affected surface roughness (p < 0.001), with finer grits producing smoother surfaces. Wood species also had a significant effect on both roughness and hardness. Sanding had the greatest influence on Ra, Rq, and Rz parameters. Ebiara exhibited the smoothest surface, while Curupay showed the highest hardness (74.65). Conclusion: Surface roughness is primarily influenced by sanding grit, whereas hardness is determined by wood species. The results emphasize the importance of tailoring sanding procedures to the wood species in order to optimize surface quality and mechanical performance in industrial and decorative applications.

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• MakaleYalnız künye2026Scopus SJRQ4/r/bayburt/11207
  CORRELATION BETWEEN THE CHEMICAL COMPOSITION OF WOOD AND THE INCREASING OF ITS CALORIFIC VALUE THROUGH HEAT TREATMENT; [CORRELAÇÃO ENTRE A COMPOSIÇÃO QUÍMICA DA MADEIRA E O AUMENTO DO PODER CALORÍFICO ATRAVÉS DO TRATAMENTO TÉRMICO]; [CORRELACIÓN ENTRE LA COMPOSICIÓN QUÍMICA DE LA MADERA Y EL AUMENTO DE SU PODER CALORÍFICO MEDIANTE TRATAMIENTO TÉRMICO]

  Domingos, Idalina; Ferreira, Miguel; Ferreira, José; Dulyanska, Yuliya; Ayata, Umit; Esteves, Bruno

  Introduction: The greatest importance of biomass lies in its Higher Heating Value (HHV), when considered for energy production. The calorific value is significantly affected by the changes in the chemical composition of the wood that occur during heat treatment. Objective: To understand the effect of heat treatment on the calorific value of the chemical constituents of two hardwoods: Sapelli and chestnut, and two softwoods: Scots pine and Siberian pine. Methods: The calorific value was determined by a Parr calorimeter – model 6400. The content of extractives was determined by successive Soxhlet extraction using about 3 g of each sample and 150 ml of dichloromethane, ethanol, and water as solvents. The extractives content was determined in accordance with TAPPI 204, and insoluble lignin by the Klason method Tappi T 222 om-02. For the determination of holocellulose, the acid chlorite method was used. Results: The calorific value of untreated wood ranged from 18.98 MJ/kg for chestnut to 20.35 MJ/kg for Siberian pine. Heat treatment resulted in an increase in the calorific value for most of the wood samples studied. Conclusion: The rise in HHV observed during heat treatment in softwoods and hardwoods is mainly due to the increase in lignin content, although dichloromethane extractives also play an important role.

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• MakaleYayıncıda açık erişim2026Scopus SJRQ3/r/bayburt/11161
  Effects of Artificial Weathering Resistance on the Hardness Value of Ash Wood Surfaces Coated with Polyurethane Modified Water-Based Varnish after Heat Treatment

  Akter, Mete; Ulay, Göksel; Peker, Hüseyin; Çakıcıer, Nevzat; Atilgan, Abdi; Ayata, Ümit

  Pendulum hardness test is important for determining the mechanical durability and long-term performance of the film layer formed on the surface of wood thermally treated at high temperatures and coated with water-based varnish (WBV). In this study, the effect of artificial weathering conditions on the pendulum hardness (König method) of ash (Fraxinus angustifolia Vahl.) wood samples varnished with polyurethane modified WBV was investigated. The samples were thermally treated under two conditions (190°C for 1.5 h and 212°C for 2 h) and compared with untreated control samples. The samples were exposed to artificial weathering conditions (for periods of 0, 168, 336 and 504 h). Pendulum hardness values were measured at the end of each weathering period. According to the results, increases in hardness values were observed in both heat-treated and untreated ash wood samples treated with varnish after weathering. In the varnished samples treated at 212°C for 2 h, the post-weathering hardness increases were lower compared to the samples treated at 190°C for 1.5 h and the control group. Additionally, analysis of variance for the pendulum hardness test, heat treatment, weathering time and their interaction were determined to be statistically significant. The significant increases in hardness values observed in the unweathered samples highlight the importance of the wood, varnish, and weathering process.

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• MakaleYalnız künye2025/r/bayburt/16149
  Determination of some surface properties in wax coatings applied on mulberry (Morus alba) wood

  Ayata, Ümit

  In this study, the surface properties of mulberry (Morus alba) wood treated with wax layers of varying coat numbers were identified and compared. The obtained data were analyzed in a statistical program, revealing generally different results. Except for the h° value, the number of coats factor was found to be significant for all tests in the variance analyses. As the number of coats increased, decreases were observed in the L* value, while increases were found in the b*, C*, and a* values. Increases in the number of coats resulted in a reduction in WI* values in both directions. The highest results in color parameters were observed in the control samples for ho and L* values, whereas for a*, b*, and C* values, they were found in the experimental samples treated with three coats of wax. The ∆E* values measured were 7.65 for one coat, 9.68 for two coats, and 12.02 for three coats of application. Increases in glossiness values were achieved in both directions at 60 and 85 degrees. The application of wax has been found to change certain optical properties of the wood.

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• MakaleAçık Erişim2025/r/bayburt/15831
  Ahşap Esaslı Kompozit Levha Malzemeleri Yüzey Renk Özellikleri Üzerine Sıcak Su Buharının Etkileri

  Ayata, Ümit; Zor, Mustafa; Ulay, Göksel; Camlibel, Osman; Peker, Hüseyin

  Bu çalışmada, HDF, MDF ve yonga levhalarına ait renk parametrelerinin sıcak su buharı uygulaması karşısında meydana gelen değişleri incelenmiştir. Sıcak su buharı, çalışmada seçilen levha türlerinin yüzeyine homojen şekilde olacak uygulanmış ve yapılan işlem sonrasında renk değişimleri bir renk cihazı ile ölçülmüştür. Elde edilen sonuçlar, sıcak su buharının özellikle MDF ve HDF üzerinde daha belirgin renk değişimlerine yol açtığını göstermektedir. Kırmızılık (a*), ışıklılık (L*), ve sarılık (b*) değerlerinde önemli artışlar gözlenmiş, özellikle MDF’de sarılık ve kırmızılık değerlerinde büyük değişimler elde edilmiştir. Buna ek olarak, renk tonu açısında ise (ho) belirgin bir azalma ve renk doygunluğu (C*) değerlerinde artış tespit edilmiştir. Sıcak su buharı uygulaması sonrasında, Yonga levha, MDF ve HDF levhalarında sırasıyla 1.42, 8.01 ve 9.25’lik ∆E* değerlerine ulaşılmış, MDF orta düzeyde bir değişim göstermiş, HDF levha en yüksek renk değişimini sunarken ve Yonga levha ise en düşük renk değişimini vermiştir. Bu bulgular, sıcak su buharı uygulamasının, MDF ve HDF gibi malzemelerin estetik özelliklerini değiştirdiğini ve bu değişimin kontrollü bir şekilde yönetilebileceğini ortaya koymaktadır. Çalışmada kullanılan sıcak su buharı uygulamasının herhangi bir kimyasal madde kullanımına gerek kalmadan yüzey özelliklerini değiştirebilmesi için kullanılabileceği ve aynı zamanda çevre dostu bir yöntem sergilediği belirlenmiştir.

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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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