Yazar "Ayata, Umit" seçeneğine göre listele
Listeleniyor 1 - 20 / 21
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Application of Synthetic-based Furniture Varnish to Various Wood Species: Comparison of Color Parameters(North Carolina State Univ Dept Wood & Paper Sci, 2025) Ulay, Goksel; Peker, Huseyin; Ayata, UmitSynthetic-based furniture varnish (colorless and glossy) was applied in two coats using a brush to the following wood types: lemon (Citrus limon (L.) surfaces were compared. The analysis of variance results for all color parameters revealed significant effects for wood type, varnish application, and their interaction. When the AE* values derived from color formulas were sorted from the lowest to the highest, they were ordered as follows: lemon, black pine, kotibe, loquat, and iroko. After varnish application, decreases in L* values were observed across all wood types, while increases in b* and C* values were detected. In black pine wood, the a* and h degrees values increased. Additionally, for iroko, loquat, and kotibe woods, there was an increase in the a* parameter, while h degrees values decreased for these wood types. Overall, the varnish application resulted in color changes in the wood materials.Öğe 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, BrunoChemical 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.Öğe 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, IdalinaChemical 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.Öğe Comparison of Color Parameters in Layers of Yacht Varnish, Waxy Varnish, and Stone Varnish Applied to Various Wood Species(Inst Technol Drewna, 2024) Ayata, Umit; Peker, HuseyinIn this study, solvent-based yacht varnish, stone varnish, and waxy varnish were applied in two coats using a brush, following industrial application standards, to the surfaces of the following tree species: black alder (Alnus glutinosa L. Gaertn.), curupay (Anadenanthera macrocarpa Benth.), iatandza (Albizia ferruginea), lemon (Citrus limon (L.) Burm.), loquat (Eriobotrya japonica L.), magnolia (Magnolia grandiflora L.), plane (Platanus orientalis L.), sucupira (Bowdichia nitida Benth.), and hornbeam (Carpinus betulus L.). Subsequently, the color parameters (b*, C*, L*, a*, ho, triangle E*, triangle H*, triangle b*, triangle C*, triangle a*, and triangle L*) of the varnish layers were compared with those of the untreated surfaces. The results of analysis of variance revealed significant differences in all color parameters. Decreases in L* values and increases in a* values were observed for all wood types when treated with three different varnishes. Additionally, in plane, black alder, and hornbeam wood, application of all varnishes resulted in increases in b* and C* values, with decreases in ho values. In sucupira wood, however, decreases were observed in b*, C*, and ho values with the application of all three varnishes. It was observed that a single type of varnish yielded different results on different wood types. This finding was attributed to the different types of resins present in the varnish types used in the study, which resulted in varying outcomes.Öğe DETERMINATION OF PENDULUM HARDNESS (KONIG METHOD) VALUES AGAINST ARTIFICIAL WEATHERING IN WATER-BASED VARNISHES APPLIED TO SOME WOOD SPECIES AFTER HEAT TREATMENT (THERMOWOOD)(Inst Technol Drewna, 2021) Ayata, Umit; Cakicier, NevzatScots pine, beech, and oak are the most important tree species in the furniture sector in Turkey. In this study, the aim is to determine pendulum hardness (Konig method) values against artificial aging in water-based varnishes applied to some wood species after heat treatment. For this purpose, Scots pine (Pinus sylvestris L.), sessile oak (Quercus petreae L.), and Eastern beech (Fagus orientalis L.) wood samples were heat-treated at 190 degrees C for 2 h and at 212 degrees C for 1-2 h according to the ThermoWood method. Later, one- and two-component water-based varnishes (WBVOne-Comp. and WBVTwo-Comp.) were applied to the material surfaces in accordance with the manufacturer's recommendations for layer thickness for industrial applications. The materials were exposed to UV light using UV-A 340 nm fluorescent lamps for 144, 288, and 432 h in a QUV accelerated weathering tester. After these weathering periods, pendulum hardness values were determined. It was found that hardness values increased after weathering, and that WBVTwo-Comp. gave higher values than WBVOne-Comp..Öğe Determination of Some Wood Properties and Response to Weathering of Citrus limon (L.) Burm Wood(North Carolina State Univ Dept Wood & Paper Sci, 2020) Sahin, Sirri; Ayata, Umit; Bal, Bekir Cihad; Esteves, Bruno; Can, Ahmet; Sivrikaya, HiiseyinThe ability of Citrus limon (L.) Burm wood to be used for flooring applications was considered in this work. Selected wood properties were determined, and the response to weathering was tested. Janka hardness, density, screw withdrawal resistance, color, glossiness, and artificial weathering (144, 288, and 432 h) were determined. The wood from Citrus limon was shown to be a dense wood with air density around 830 kg/m(3) and with a high Janka hardness of 138.0 N/mm(2), 120.4 N/mm(2), and 115.9 N/mm(2) for cross, tangential, and radial sections, respectively. This opens good perspectives to this kind of wood being used for flooring. Statistical analysis showed that both Janka hardness and screw withdrawal resistance were significantly different between surfaces. Nevertheless, the homogeneity groups showed that the main differences were between the surfaces in the longitudinal direction when compared with the transverse direction. The wood is lighter than most common woods and it is mainly yellow. After weathering, the wood became darker, redder, and yellower. Glossiness decreased in the first hours of the weathering period.Öğe Determination of Thermal Conductivity Properties in Some Wood Species Obtained from Turkey(North Carolina State Univ Dept Wood & Paper Sci, 2019) Cavus, Vedat; Sahin, Siri; Esteves, Bruno; Ayata, UmitWith the increased awareness of thermal insulation of buildings, the knowledge of thermal conductivity of non-structural materials applied for roughing, cladding or flooring has become more important. The objective of this study was to investigate the thermal conductivity of 31 different wood species originated from the region of Izmir in Turkey. Thermal conductivity of air dried boards was determined in accordance to ASTM 5334 standard which measures this property on the interior of wood rather than on the surface. Thermal conductivity varied from 0.090 to 0.197 W/ mK. The highest thermal conductivity was obtained for oak and the lowest for Canadian poplar. A linear relation was obtained between wood density and thermal conductivity.Öğe 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, MutluThe 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.Öğe Effect of Calcium Lignosulfonate Additive on Some Physical and Mechanical Properties of High-Density Fiberboard(Inst Technol Drewna, 2024) Camlibel, Osman; Ayata, Umit; Peker, HuseyinCalcium lignosulfonate (CLS) (C20H24CaO10S2) is widely used in various industries today, including wood, construction, food, agriculture, and textiles. There are currently few studies on the addition of CLS chemicals to various fiberboards. This study was designed to explore the outcomes of the interaction between CLS and the boards, with the aim of expanding the potential applications of this chemical. We incorporated CLS at varying percentages (6%, 8%, and 10%) as an adhesive additive in high-density fiberboard (HDF) produced using urea-formaldehyde (UF) resin in a laboratory setting. We assessed its impact on several physical properties - thickness swelling (TS), density, and water absorption (WA) - and mechanical properties: modulus of rupture (MOR), internal bond strength (IB), modulus of elasticity (MOE), and surface soundness (SS). A control group was created using prepared boards, enabling the comparison of results between boards made with and without CLS additives. According to the results of a multivariate analysis of variance, the CLS percentage showed no significant effect on density, MOE, and SS. However, it significantly influenced TS, WA, IB, and MOR, resulting in reductions of 4-12% for SS, 6-12% for MOR, and 2-22% for IB, while increasing TS by 20-130%, WA by 25-84%, and MOE by 1-3%. It was observed that the use of CLS led to differing results in the tests conducted on the produced HDF materials.Öğe 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, LeventHardness 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.Öğe Effect of Thermal Modification and Picture Varnish Application on Color Change of Scots Pine (Pinus Sylvestris L.) Wood(Lukasiewicz Research Network, Poznan Inst Technology, 2025) Peker, Huseyin; Ayata, Umit; Ulay, GokselScots pine is one of the important tree species used by the wood processing industry in many countries for both interior and exterior applications. It is well known that thermal treatment alters the color of wood. To protect wood from outdoor environmental conditions, certain chemicals are applied to its surface. These protective chemicals also influence the color of thermally treated wood. In this study, the color-altering effect of picture varnish (refined linseed oil), commonly used as a protective chemical in the field of painting, was investigated on both thermally treated and untreated wood materials. Scots pine (Pinus sylvestris L.) wood samples were subjected to thermal treatment at 212 degrees C for 2 h. Following this, varnish made from refined linseed oil was applied to some of these samples and some untreated samples, with the remaining untreated samples used as controls. Color and whiteness index (WI*) values were analyzed on the resulting four different materials, and the results were compared. Analysis of variance showed significant effects for the factors of heat treatment, picture varnish application, and their interaction, on WI* (& boxV; and perpendicular to), a*, L*, ho, b*, and C* values. In the non-heat-treated samples, the application of varnish resulted in reductions in WI* values in both directions and in L* values, while increases were observed in ho, b*, C*, and a* values. Additionally, the application of varnish to the heat-treated samples resulted in an increase in a* values, while reductions were observed in WI* values in both directions, as well as in ho, L*, b*, and C* values. After heat treatment, the triangle E* value for Scots pine wood was calculated as 33.63. For both heat-treated and non-heat-treated samples, varnish application resulted in negative triangle L* values and positive triangle a* values. Additionally, triangle b* and triangle C* values were positive in the non-heat-treated and varnished samples, while they were negative in the heat-treated and varnished samples. The protective picture varnish used in the study significantly altered the color of both thermally treated and untreated wood.Öğe 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, UmitRadiata 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.Öğe Effects of Artificial Weathering on the Surface Properties of Ultraviolet Varnish Applied to Lemonwood (Citrus limon (L.) Burm.)(North Carolina State Univ Dept Wood & Paper Sci, 2019) Ayata, UmitUltraviolet varnishes are widely used for production processes in the parquet industry. A large number of chemicals are used in this sector, and each one has different characteristics. In this study, the effects of accelerated aging of ultraviolet varnish (3 and 5 coats) when applied to lemonwood (Citrus limon ( L.) Burm.) (grown in Mezitli, Mersin, Turkey) were investigated. The ultraviolet varnish coated samples were subjected to aging processes (144 h, 288 h, and 432 h) by using UV-A 340 nm lamps. Color (L*, a*, b*, and Delta E*) parameters, glossiness (perpendicular (perpendicular to) and parallel (//) at 20 degrees, 60 degrees, and 85 degrees), and surface adhesion strength via the pull-off method for ultraviolet varnish coated samples were quantified before and after weathering. According to the results, the varnish type, aging period, and interaction between all studied variables, i.e. L*, a*, b* color parameters, glossiness (perpendicular (perpendicular to) and parallel (//) at 20 degrees, 60 degrees, and 85 degrees), and adhesion strength were found to alter the surface properties. As a result, the lemon tree can be used in the production of an ultraviolet parquet system.Öğe Effects of Formaldehyde Scavenger on Mechanical, Physical, and Emission Test Results in Multi-Layer Pressed Chipboard Production(Inst Technol Drewna, 2025) Camlibel, Osman; Peker, Huseyin; Ayata, Umit; Ulay, GokselThis study investigates the effects of different formaldehyde scavenger (FS) ratios on the physical, mechanical, and chemical properties of fiberboard composites. Experimental analyses included measurements of thickness, density, modulus of rupture (MOR), modulus of elasticity (MOE), internal (WA), and formaldehyde emission (FE) levels. The results indicate that an increase in the FS ratio leads to a significant decline in mechanical properties. Specifically, MOR, MOE, and IB values decreased by 17.97%, 15.65%, and 16.33%, respectively. Changes in TS and WA were also observed, with TS increasing by up to 22.68% and WA decreasing by as much as 16.90%. In terms of formaldehyde emissions, a significant reduction was observed as the FS ratio increased. At a 15% FS ratio, formaldehyde emissions decreased by 43.24%, which is considered a positive outcome in terms of environmental and health impacts. Overall, the use of FS in specific ratios reduces FE while causing certain reductions in mechanical properties. These findings highlight the importance of optimizing FS usage for the production of low-FE fiberboards.Öğe 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, NevzatLinden 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.Öğe İzmir’de Yetişen İğde (Elaeagnus angustifolia L.) Odununda Bazı Fiziksel ve Mekanik Özelliklerinin Belirlenmesi(2019) Ayata, Umit; Bal, Bekir CihadOdun hammaddesi önemli mühendislik malzemelerinden birisidir. Özellikle, yenilenebilir olması, ucuz olması, kolay temin edilebilmesi, kolay işlenmesi, çevre dostu olması ve estetik bakımdan tercihe edilmesi önemli üstünlüklerindendir. Odunun kullanım yerine karar verirken, onun bazı teknolojik özelliklerinin iyi bilinmesi gerekmektedir. Yapılan önceki çalışmalarda, iğde odununun fiziksel ve mekanik özellikleri üzerine yeterli çalışmaya ulaşılamamıştır. Bu nedenle, bu çalışmada, İzmir’de yetişen iğde (Elaeagnus angustifolia L.) odununa ait bazı fiziksel ve mekanik özellikleri araştırılmıştır. Elde edilen bulgulara göre; hava kurusu rutubet değeri %9,93, hava kurusu yoğunluk (D12) 536 kg/m3, tam kuru yoğunluk (Do) 507 kg/m3, teğet yönde genişleme (?t) %5,90, radyal yönde genişleme (?r) %3,24, boyuna yönde genişleme (?ı) %0,30, hacmen genişleme (?v) %9,44, lif doygunluğu noktası (LDN) %18,63. Şok direnci 0,389 kgm/cm2, eğilme direnci 61,12 N/mm2 ve elastikiyet modülü tayini 4663 N/mm2, janka sertlik değeri teğet, radyal ve enine yüzeyler için sırasıyla 40,23 N/mm2, 40,10 N/mm2 ve 58,74 N/mm2 olarak tespit edilmiştir.Öğe 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, IdalinaThe 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.Öğe Some Physical, Biological, Hardness, and Color Properties of Wood Impregnated with Propolis(Aves, 2022) Akcay, Caglar; Ayata, Umit; Birinci, Emre; Yalcin, Mesut; Kolayli, SevgiPropolis is a bee product collected by honeybees from various tree species in nature. It has antifungal, antibacterial, antioxidant, and anticancerogenic properties. Recently, propolis has been used in wood protection area because it has antifungal properties and is a natural and environmentally friendly material. In this study, some deciduous wood species were treated with methanolic propolis extracts. Propolis solutions were prepared by dissolving propolis in methanol in concentrations of 0.5%, 2.5%, 5%, and 8%. These solutions were forced deep into the Scots pine (Pinus sylvestris L.), fir (Abies nordmanniana), and spruce (Picea orientalis L.) woodblocks under vacuum and pressure. Water uptake and water-repellent efficiencies of the woodblocks were tested at 2-, 4-, and 20-hour immersion periods. Sample blocks were tested against wood-destroying house borer (Hylotrupes bajulus) (Coleoptera, Cerambycidae) larvae for 21 weeks. In addition, color changes of woodblocks treated with propolis were determined. According to results obtained in the study, the highest water-repellent efficiency was 61.4% in propolis-impregnated spruce wood at concentration level of 8% during the 2-hour period. These results show that propolis extracts could be used as hydrophobic material for wood. Larvae mortality rates indicated that 8% concentration level was not adequate to overcome H. bajulus larvae or propolis is not effective against H. bajulus larvae. While L* value decreases with the increase of impregnation rate, a* and b* values increase in all wood types. As the impregnation rate increased, the total color difference also increased.Öğe Testing of Bleaching Application on Kingwood (Dalbergia cearensis Ducke) Wood(Zagreb Univ, Fac Forestry, 2025) Peker, Huseyin; Ayata, UmitIn this study, surface changes (whiteness index: WI*, color parameters, and glossiness properties) occurring after bleaching with oxalic acid (C2H2O4) and hydrogen peroxide (H2O2) + sodium hydroxide (NaOH) chemicals in kingwood (Dalbergia cearensis Ducke) wood, used for high-quality applications such as quality turning, marquetry, furniture, inlay work, musical instruments, and decorative items, were investigated. The Delta E* values were determined as 5.46 for the single component and 8.69 for the double component. Decreases in L* and ho parameters were obtained by the action of the C2H2O4 chemical, while increases were observed in the a*, C*, and b* parameters. Additionally, the use ofH2O2 + NaOH chemicals in the bleaching process resulted in increases in L*, b*, C*, and ho values, with a decrease noted in the a*parameter. Observations revealed reductions in glossiness values at 60 and 85 degrees when employing two distinct bleaching agents in both orientations. It can be said that the bleaching agents used in the study exert varying effects as modifiers on the surface of wooden materials.Öğe The Effect of Weathering on Color and Glossiness Properties of Polyurethane-Modified Water-Based Varnish Layers Applied to Thermally Treated Ash Wood(North Carolina State Univ Dept Wood & Paper Sci, 2025) Ulay, Goksel; Akter, Mete; Cakicier, Nevzat; Peker, Huseyin; Ayata, Umit; Atilgan, Abdi; Ciftci, SeymenThe effects of artificial weathering (168, 336, and 504 h) on the glossiness values and color parameters of varnished, polyurethane-modified ash wood were investigated. Samples included control samples without treatment and thermally treated samples under two different conditions (190 degrees C for 1.5 h and 212 degrees C for 2 h), all coated with a polyurethane-modified water-based varnish. In non-thermally treated and varnished samples, decreases in L* values were observed after weathering, while increases were noted in h(o), C*, b*, and glossiness at 60 degrees in both perpendicular and parallel directions to the fibers. After weathering, for samples thermally treated at 190 degrees C for 1.5 h and varnished, increases were observed in glossiness values at 20 degrees and 60 degrees in both directions, as well as in L*, b*, and h(o) values. Conversely, decreases were noted in a* and C* values. In samples thermally treated at 212 degrees C for 2 h and varnished, increases in a*, L*, h(o), b*, and C* values were detected after weathering, whereas decreases were observed in glossiness at all angles (20 degrees and 60 degrees) in both directions. The triangle E* values showed a decreasing trend in non-thermally treated varnished samples after weathering, while an increase was observed in samples thermally treated at 212 degrees C for 2 h and varnished.
