Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Ayata, Ümit(4)
- Domingos, Idalina(4)
- Esteves, Bruno(4)
- Ferreira, José(4)
- Ayata, Umit(3)
- Ulay, Göksel(2)
- Bayraktar, M. Kilic(1)
- Boncukcuoʇlu, Recep(1)
- Brás, Isabel(1)
- Cruz-Lopes, Luisa(1)
- Cruz-Lopes, Luísa(1)
- Dulyanska, Yuliya(1)
- Ertuʇrul, Mehmet(1)
- Fagan, C.C.(1)
- Ferreira, Miguel(1)
- Gürleyen, Levent(1)
- Harbourne, N.B.(1)
- Karakaş, Ibrahim Hakki(1)
- Karcioʇlu Karakaş, Zeynep(1)
- Peker, Hüseyin(1)
- Sahin, Sirri(1)
- Sahin, Sırrı(1)
- Sen, Ali(1)
- Çakicier, Nevzat(1)
Yayınlar
- MakaleYalnız künye2026Scopus SJRQ4CORRELATION 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.
- MakaleAçık Erişim2025Scopus SJRQ3Effect of Thermal Modification and Picture Varnish Application on Color Change of Scots Pine (Pinus Sylvestris L.) Wood
Peker, Hüseyin; Ayata, Ümit; Ulay, Göksel
Scots 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 °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* (|| and ⊥), 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 ∆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 ∆L* values and positive ∆a* values. Additionally, ∆b* and ∆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.
- MakaleAçık Erişim2023The effects of artificial weathering on the pendulum hardness of chestnut wood applied with polyurethane varnish after heat treatment; [Isıl işlem sonrası poliüretan vernik uygulanmış kestane odununda salınımsal sertlik üzerine yapay yaşlandırmanın etkileri]
Ulay, Göksel; Ayata, Ümit
The effects of artificial weathering (576 h) on the pendulum hardness values of Anatolian chestnut (Castanea sativa Mill.) wood applied with polyurethane varnish (PU) after heat treatment at 190°C for 1.5 h and at 212°C for 2 h were investigated. The results revealed that heat treatment, weathering period, and interaction were significant. The hardness values of the heat-treated materials were higher than those of the non-heat-treated test samples. The highest hardness value was determined in the un-weathered group of the test samples that were heat-treated at 190°C for 1.5 h while the lowest value was determined in the group that was heat-treated at 190°C for 1.5 h and weathered for 432 h. The highest reduction rates after weathering were obtained on samples that were heat-treated at 190°C for 1.5 h, followed by heat-treated at 212°C for 2 h and non-heat-treated. It was observed that the heat treatment application caused different pendulum hardness values in chestnut wood samples covered with polyurethane varnish.
AtıfScopus3OpenAlex2
İncele - MakaleAçık Erişim2022Scopus SJRQ2EXTRACTIVES 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.
AtıfScopus20WoS20OpenAlex16
İncele - MakaleAçık Erişim2021Scopus SJRQ3Effect of Heat Treatment on Shore-D Hardness of Some Wood Species
Esteves, Bruno; Sahin, Sırrı; Ayata, Ümit; Domingos, Idalina; Ferreira, José; Gürleyen, 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 °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.
AtıfScopus23WoS17OpenAlex24İncele - MakaleAçık Erişim2021Scopus SJRQ2Determination of pendulum hardness (KÖnig method) values against artificial weathering in water-based varnishes applied to some wood species after heat treatment (thermowood)
Ayata, Ümit; Çakicier, Nevzat
Scots 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 (König 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 °C for 2 h and at 212 °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..
AtıfScopus4WoS4OpenAlex3İncele - MakaleAçık Erişim2020Scopus SJRQ2Calorific power improvement of wood by heat treatment and its relation to chemical composition
Domingos, Idalina; Ayata, Umit; Ferreira, José; 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 (R2 = 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 (R2 = 0.04). The same was obtained in relation to ethanol extractives with R2 = 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.
AtıfScopus32WoS27OpenAlex38İncele - MakaleAçık Erişim2019Scopus SJRQ1Impact of heat treatment and acid gelation on polyphenol enriched milk samples
Bayraktar, M. Kilic; Harbourne, N.B.; Fagan, C.C.
The effects of heat treatment and the stage of polyphenol addition to milk before or after heat treatment on the total phenolic content (TPC), ferric-ion reducing antioxidant power (FRAP), pH, casein micelle size (CMS) and whey protein denaturation content of milk-polyphenol mixtures were investigated. Four sources of phenolic compounds (green tea, white grape, tannic acid, gallic acid) were incorporated into pasteurized-skim milk. A heat treatment (85 °C for 30 min) was applied to pasteurized-skim milk either before (MhP) or after polyphenols addition (MhPh). Acid milk gels were produced using MhPh samples, and their TPC and FRAP were determined. Heat treatment decreased the TPC and FRAP values of the samples, except for tannic acid, probably due to increased polyphenol-protein interactions. However, MhPh tannic acid sample resulted in significantly higher FRAP value than MhP. The addition of gallic acid before heat treatment (MhPh) significantly increased CMS due to the lower pH of this sample during heating. Acid gelation decreased the extractable polyphenols, however there was no significant different on FRAP between acid gel and MhPh milk samples. This study showed that the properties of phenolic source, particularly pH, and the stage of polyphenol addition to milk had an impact on selected properties.
AtıfScopus25WoS23OpenAlex24İncele - MakaleAçık Erişim2015Scopus SJRQ1The effects of heat treatment on the synthesis of nickel ferrite (NiFe2O4) nanoparticles using the microwave assisted combustion method
Karcioʇlu Karakaş, Zeynep; Boncukcuoʇlu, Recep; Karakaş, Ibrahim Hakki; Ertuʇrul, Mehmet
NiFe2O4nanoparticles were synthesized using the microwave assisted combustion method based on metal nitrate salts and urea. To remain of organic matters and to stabilize the particles, samples were thermally treated at various temperatures from 300-800 °C. The prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) thermogravimetric analysis (TGA) and vibrating sample magnetometry (VSM). The heat treated samples show the reflection planes of (111), (220), (222), (311), (400), (422), (511), and (440) which perfectly confirm to a cubic spinel phase of NiFe2O4and no secondary phases were detected in the XRD patterns of the samples. The crystallite sizes calculated using the Debye-Scherrer formula were found to increase with the heat treatment temperature, from about 4 nm at 300 °C-85 nm at 800 °C. EDX results verify that the compositional mass rations were relevant, as expected from the synthesis. The micrographs of SEM and TEM showed that all of the samples have nano-crystalline behavior and particles indication cubic shape. Magnetization measurements were obtained at room temperature by using a VSM, which demonstrated that the all of the samples synthesized with heat treatment exhibited ferromagnetic behaviors.
AtıfScopus96WoS86OpenAlex95İncele