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Öğe ANATOMICAL INVESTIGATION OF THERMALLY COMPRESSED WOOD PANELS(North Carolina State Univ Dept Wood & Paper Sci, 2010) Doğu, Dilek; Tırak, Kamile; Candan, Zeki; Ünsal, ÖnerEffects of temperature and press pressure on the anatomical structure of solid-wood panels produced by using Pinus sylvestris L. (Scotch pine) wood were evaluated. Solid wood panels with dimensions of 250 by 500 by 18 mm were hot-pressed using a laboratory hot press at a temperature of either 120 degrees C or 150 degrees C and pressure of either 5 or 7 MPa for 1 h. Microscopic investigations conducted by Light Microscopy (LM) and Scanning Electron Microscopy (SEM) showed that the highest deformation occurred in earlywood regions of all growth rings for each process condition and the distribution of deformation was not uniform in growth rings. Cell-wall thickness was observed to be an important factor in wood behavior during thermal compressing processes. The results showed clearly that the impact of pressure in wood structure is promoted by increased temperature. Significant densification was observed at the maximum temperature and maximum pressure condition employed in the study, and almost all earlywood layers showed cell collapse. The study revealed that a homogenous structure of growth rings with the uniform earlywood and latewood widths throughout the wood samples plays a major role in prevention of cell collapse. The results indicated that both process conditions and anatomical structure of the wood have an interaction.Öğe BAZI AĞAÇ TÜRLERİNE UYGULANAN JANKA SERTLİK DİRENCİNDE ISIL İŞLEMİN (THERMOWOOD) ETKİSİ(Düzce Üniversitesi, 2017) Gürleyen, Tuğba; Güler, Cengiz; Ünsal, ÖnerBu çalışmada, ısılişlem görmüş ve görmemiş Amerikan dişbudak (Fraxinusamericana L.), Avrupa kızılağacı (Alnusincana L.), ak kavak (Populus alba L.)ve ak söğüt (Salix alba L.)odunlarına ait janka sertlik özellikleri belirlenmiştir. Bu ağaç türleriThermoWood metoduna göre 190oC’de 1.5 saat, 212°C’de 2 saat sürelerile ısıl işleme tabi tutulmuştur. Daha sonra ısıl işlem görmüş ve görmemiş(kontrol) test örnekleri üzerinde radyal, teğet ve enine kesit yönde sertlik(janka) değerleri belirlenmiştir. Araştırma sonuçlarına göre; ısıl işlemuygulaması ile sertlikdeğerlerinin ağaç türlerine göre değişkenlik gösterdiği ortaya çıkmıştır.Öğe The effect of boiling time on the surface roughness of rotary-cut veneers from oriental beech (Fagus orientalis L.)(Elsevier Science Sa, 2008) Dündar, Türker; As, Nusret; Korkut, Süleyman; Ünsal, ÖnerThe objective of this study was to investigate effects of boiling time on surface roughness of beech (Fagus orientalis L.) veneer manufactured using the rotary cutting method. Three logs of oriental beech were subjected to softening process by boiling them in water (60-70 degrees C) for various times (e.g. 20,40, and 60 h) and they were peeled immediately. For surface roughness, veneer samples were taken from outer, center, and inner (near to pit) parts of logs and the distance of the locations where the samples were taken from the pith were the same. Veneer specimens have a dimension of 10 cm (width) by 20 cm (length) by 0.14 cm (thickness). Three roughness parameters, average roughness (R-a), mean peak-to-valley height (R-z), and maximum roughness (R.) for each group were measured according to DIN standard 4768 by using stylus profilometer and compared with one another. Except the boiling time, other factors (species, knife angle, peeling angel, etc.) were kept the same. The results show that, the surface of veneers, taken from heartwood and center of the logs boiled 60 h were significantly rougher than 20 and 40 h. But peeling veneers obtained from sapwood of logs boiled 20 h displayed significantly rougher surface than 40 and 60 h. For all samples, applying 40-h boiling period can minimize the roughness value. Therefore, it seems that 40-h boiling period is suitable in order to minimize the surface roughness of rotary-cut veneers manufactured from all of beech (F. orientalis L.) logs parts (inner, center, and outer) (C) 2007 Elsevier B.V. All rights reserved.Öğe Effect of Heat Treatment of Wild Cherry Wood on Abrasion Resistance and Withdrawal Capacity of Screws(Zagreb Univ, Fac Forestry, 2015) Aytin, Ayhan; Korkut, Süleyman; As, Nusret; Ünsal, Öner; Gündüz, GökhanIn its wise use, many properties of wood are important. Among these properties, wood abrasion resistance (AR) and withdrawal capacity of screws (WCS) are deemed to be relatively significant. It is well know that heat treatment changes the resistance features of wooden materials by changing the structural characteristics of wood. Within the scope of this study, the effects were investigated of the temperature and duration of heat treatment of Wild Cherry (Cerasus avium (L.) Monench) on its AR and its WCS in the radial direction and tangential direction. The test results indicated that weight loss (WL) and thickness reduction (TR) remained almost the same in the radial direction specimen, but there was significant TR in the tangential direction specimen. As a result of these changes, the abrasion effect of the S-42 abrader diminished based on the increase in the number of cycles. However, in both the radial and tangential direction, the WCS decreased to a significantly greater extent in the heat-treated specimens than in the control specimens.Öğe Effect of thermal modification by hot pressing on performance properties of paulownia wood boards(Elsevier Science Bv, 2013) Candan, Zeki; Korkut, Süleyman; Ünsal, ÖnerThe goal of this study was to investigate the effects of thermal modification by hot-pressing on the performance properties of paulownia wood boards. The boards were thermally modified by hot-pressing method under different pressure and temperature levels. As two boards for each modification group plus two for unmodified, totally 10 experimental wood boards were prepared in this study. Main density, vertical density profile (VDP), thickness swell (TS), water absorption (WA), moisture content (MC), and hardness tests were carried out to evaluate the performance properties of the thermally modified or unmodified wood boards. The results obtained in this study indicated that surface density of the boards increased with increasing press pressure. The thermal modification negatively affected the TS and WA values of the boards. Hardness values of the wood boards were significantly improved by the thermal modification. The results of this research revealed that the thermally compressing method could be used to improve end-use properties of low-density wood materials made from fast-growing tree species such as paulownia, poplar, eucalyptus etc. Thus low-value wood materials could be converted to value-added products. In addition, sustainable management of natural resources could be achieved by using the thermal modification method. (C) 2012 Elsevier B.V. All rights reserved.Öğe The Effects of Heat Treatment with the ThermoWood (R) Method on the Equilibrium Moisture Content and Dimensional Stability of Wild Cherry Wood(North Carolina State Univ Dept Wood & Paper Sci, 2015) Aytin, Ayhan; Korkut, Süleyman; Ünsal, Öner; Çakıcıer, NevzatLow hygroscopicity is an important factor favoring the use of heat-treated wood materials. Hence, wild cherry (Cerasus avium (L.) Moench) wood was subjected to heat treatment with the ThermoWood (R) method for about 1 and 2 hours at temperatures of 190 and 212 degrees C in an industrial business. Then, trial samples were prepared and divided into two groups. By being conditioned in the environments of 20 degrees C and 65% relative humidity (WC1), 20 degrees C and 85% relative humidity (WC2), 20 degrees C and 30% relative humidity (WC3), and 23 degrees C and 50% relative humidity (WC4), equilibrium moisture content (EMC) and dimensional stability (DS) values of the samples in the first group were determined. The water thickness swelling (WTS) and water retention (WR) features of the samples of the second group were examined by keeping them in water both 24 and 72 h. The results show that EMC and WTS decreased with increasing treatment temperature and durations. Also, DS was improved. On the other hand, the WR values of all the samples stayed approximately the same.Öğe EFFECTS OF THERMAL MODIFICATION ON SURFACE CHARACTERISTICS OF OSB PANELS(Slovak Forest Products Research Inst, 2010) Ünsal, Öner; Candan, Zeki; Büyüksarı, Ümit; Korkut, Süleyman; Babiak, MarianThermal modification is an effective process to improve dimensional stability of wood and wood composite panels. Wettability of wood based panels is also an important issue and has been affected from heat treatment process. In this study oriented strandboard (OSB) panels were subjected thermal modification process. Wettability and surface roughness properties of the panels were evaluated. The results obtained in this study showed that the thermal modification process improved surface roughness parameters of all the treated panels compared to untreated control panels. The contact angle (CA) values of the treated panels were clearly higher than the untreated panels. The thermally treated panels had a poorer wettability property when compared to the untreated panels. The panels having smoother surface had greater CA values.Öğe EVALUATION OF KILN-DRYING SCHEDULES FOR WILD CHERRY WOOD (CERASUS AVIUM)(Univ Bio-Bio, 2013) Korkut, Süleyman; Ünsal, Öner; Kocaefe, Duygu; Aytin, Ayhan; Gökyar, AslıWild cherry wood (Cerasus avium) lumber with a nominal thickness of 5 cm from Duzce region in Turkey was dried through conventional kiln drying using two different programs which are unprotective drying schedules, and protective drying schedules. The aim was to obtain the most desirable kiln schedule for keeping the wood quality at an appropriate level up to final moisture content of 12 +/- 2% was reached. Intensity of warping (twist, bow, cup, crook) occurrence, superficial, internal and end checks, residual stresses, drying rate, and moisture gradient in the dried woods were measured, and the results were analyzed. The results showed that there was a more homogeneous moisture profile, fewer occurrences of superficial checks, and absence of internal checks in the protective drying schedules due to low warping values compared to the unprotective drying schedules. Therefore, it seems that protective drying schedules might be recommended as optimum program for wild cherry lumber drying at commercial scale from Duzce region.Öğe MICROSCOPIC INVESTIGATION OF DEFECTS IN THERMALLY COMPRESSED POPLAR WOOD PANELS(Univ Bio-Bio, 2016) Doğu, Dilek; Bakır, Davut; Tuncer, F. Diğdem; Hızal, Kamile Tırak; Ünsal, Öner; Candan, ZekiThe combined effects of temperature and compression on the microstructure of solid-wood panels produced by Aspen (Populus tremula) wood were evaluated. Thermal compression was applied on aspen wood to increase the density for improving its physical and mechanical properties. The solid wood panels with dimensions of 100 mm by 500 mm by 25 mm were hot-pressed by using a laboratory hot press at a temperature of either 150 degrees C or 170 degrees C and pressure of either 1MPa or 2 MPa, respectively, for 45 min. Changes in the microstructure were detected by using a light microscope. The microscopic investigations revealed that the wood exhibited much defects in the process conditions of 170 degrees C / 2 MPa, and the distribution of defects were not uniform in the growth rings of the wood specimens in the two treatment groups. All defects in cell structure were quite distinct in the beginning and the last parts of the growth rings and the largest damages occurred in the fibers and vessels for the two process conditions. The results indicate that growth ring structure, vessel porosity, and cell wall thickness have a strong effect on wood behavior in various process conditions.Öğe SARIÇAM KERESTESİNİN KURUTULMASINDA AKUSTİK EMİSYON YÖNTEMİNİN KULLANILMASI(Düzce Üniversitesi, 2016) Ünsal, Öner; Dündar, Türker; As, Nusret; Korkut, Süleyman; Görgün, H. Volkan; Kaymakçı, AlperenTÜBİTAK 1001 projesi (Proje no: 112-O-818) olarak yapılan çalışmada, teknik olarak kurutulması güç ve uzun süreli olan Sapsız Meşe (6cm) ve Doğu Kayını (8cm) kerestesi yanında, 10 cm kalınlığında Sarıçam kerestesini kurutmada akustik emisyon (AE) yöntemini kullanarak, ağaç malzemeyi tahrip etmeden ulaşabilecek minimum kurutma sürelerini veren kurutma programlarının belirlenmesi hedeflenmiştir. AE yönteminde hedef, AE cihazı yardımıyla kurutma sürecinde ağaç malzemede oluşması muhtemel çatlak ve deformasyon gibi kusur oluşumlarını haber veren ses dalgalarını tespit etmek ve bu noktada kurutma şartlarına anında müdahale ederek kusur oluşumunu ortadan kaldırmaktır. Bu amaçla, önceden belirlenmiş kurutma programlarını uygularken AE cihazıyla eş zamanlı olarak ölçümler alınmış, bu süreçte sürekli ses dalgalarının takibi yapılarak kusurların oluşumunu haber veren frekanslarla ilgili eşik değerler belirlenmiş, daha sonra yapılan kurutma denemelerinde de bu eşik değerleri aşan durumlarda kurutma şartlarından ortam sıcaklığı ve bağıl nemine müdahale edilerek o ağaç türünün o kalınlığı için uygulanabilecek optimum kurutma programına ulaşılması sağlanmıştır. Bu sayede, hem haftalar veya aylar süren kurutma sürelerinin aşağı çekilmesi ve hem de ciddi maliyet oluşturan kurutma giderlerinden önemli tasarruflar sağlanması öngörülmüştür. Sarıçam kerestesiyle yapılan ve AE ölçümleriyle kombine edilen kurutma denemeleri sonunda, 10 cm'lik Sarıçam için, %50-15 kereste nemi aralığında, kurutma kusurlarının ve kurutma giderlerinin minimize edildiği ideal kurutma süresinin 10 gün olabileceği ve bu sayede kurutma giderlerinden %35'e varan oranda tasarruf sağlanabileceği belirlenmiştirÖğe Sarıçam’da Koniklik ve Eğriliğin Randıman Üzerine Etkisi(Düzce Üniversitesi, 2008) Kantay, Ramazan; Ünsal, Öner; Müge Güngör, Nur; Çelik, MuratIn this study; it is determined that quantitative yield have obtained with sawing of54 mm thickness lumbers live saw method of logs obtained from Scots pine (Pinussylvestris L.) that is commonly worked up and used a tree species in the lumberindustry in Turkey. The logs used in the experiments were harvested from BelgradForest. Acording to the results, while log conicness and crookedness increases,quantitative yield decreases in all diameter classes.Öğe Thermally Compressed Poplar Wood (TCW): Physical and Mechanical Properties(Zagreb Univ, Fac Forestry, 2013) Candan, Zeki; Korkut, Süleyman; Ünsal, ÖnerVarious thermal modification techniques are used to improve some properties of wood materials. Thermally compressed wood (TCW) is obtained by using a hot-press. This study investigates the effect of thermal compression on the density, vertical density profile (VDP), moisture content (MC), thickness swelling (TS), Janka hardness, and drying characteristics of the poplar wood boards. The experimental boards were cut from poplar wood (Populus spp). The boards with dimensions of 100 mm by 500 mm by 25 nun were thermally compressed at press temperature of either 150 degrees C or 170 degrees C, press pressure of either 1 or 2 MPa for 45 minutes in a hot-press. A total of 10 experimental boards were prepared - two boards for each group plus two for control. The results obtained in this study indicated that the density and Janka hardness values increased with the increase of the press pressure. The thermal compression process decreased the thickness of the boards. The thickness reduction increased with the increase of the press pressure. An improvement was not seen in the TS values of the samples when compared to those of the untreated samples. This study revealed that the thermal compression technique should be used to improve some properties of poplar wood. In this way better use could be made of low-cost poplar wood.Öğe THERMOWOOD YÖNTEMİ İLE ISIL İŞLEMİN YABANİ KİRAZ ODUNUNDA BAZI MEKANİK ÖZELLİKLER ÜZERİNE ETKİSİ(Düzce Üniversitesi, 2017) Aytin, Ayhan; Korkut, Süleyman; Ünsal, Öner; As, NusretBu çalışmadaki amaç değişik sıcaklık ve sürelerde kombinasyonlaroluşturularak ThermoWood yöntemi ile ısıl işleme tabi tutulan Yabani Kiraz (Cerasus avium(L.) Monench) odununda bazımekanik direnç değerlerinin değişimi belirlenmiştir. nbsp; Deneme ağaçları ilk olarak 190°C ve 212°Csıcaklıklarda 1 ve 2 saat ısıl işleme tabi tutulmuş ve ThermoWood Yabani Kiraz(Cerasus avium(L.) Monench) eldeedilmiştir. Daha sonra kontrol grubu(1) ve ThemoWood(4) olmak üzere hazırlananküçük boyutlu test örneklerine statik eğilme ve statik eğilmede elastikiyetmodülü testleri uygulanmıştır. Test sonuçları ısıl işlem görmüş tüm gruplardakontrol örneklerine göre; statik eğilme direnci değerinin azaldığını, bunakarşılık statik eğilmede elastikiyet modülünde ise tüm gruplarda artış olduğunuortaya koymuştur. nbsp; nbsp;Öğe THERMOWOOD YÖNTEMİ İLE ISIL İŞLEMİN YABANİ KİRAZ ODUNUNDA YOĞUNLUK, BOYUTSAL STABİTE VE BASINÇ DİRENCİ ÜZERİNE ETKİSİ(Düzce Üniversitesi, 2016) Aytin, Ayhan; Korkut, Süleyman; Ünsal, Öner; As, Nusret; Çakıcıer, NevzatAğaç malzemenin ısıl işlemi, 1990 yıllardan itibaren ondan daha rasyonel yararlanmaya yönelik adımların bir parçası olarak önem kazanan bir modifikasyon yöntemidir. Isıl işlem ile bazı kullanım yerleri için çevreye zararlı herhangi bir etki meydana getirilmeden yapısı değiştirilmiş ağaç malzeme elde edilmektedir. Çeşitli ağaç türleri üzerinde farklı yöntemler ile ısıl işlem uygulanarak elde edilen sonuçlara göre belli bir disiplin oluşturulurken aynı zamanda kullanıcılar da uygun malzeme konusunda yönlendirilmektedir. Bu çalışmada, Yabani Kiraz (Cerasus avium(L.) Monench) odunu ThermoWood yöntemi ile 190°C ve 212°C sıcaklıklarda 1 ve 2 saat ısıl işleme tabi tutulduktan sonra bazı fiziksel ve mekanik özellikler araştırılmıştır. Fiziksel özelliklerden elde edilen sonuçlar kontrol örneklerine göre ısıl işlem ile birlikte tam kuru özgül ağırlık, hava kurusu özgül ağırlık, daralma ve genişleme miktarlarının azaldığı, mekanik özeliklerden liflere paralel basınç direncinde ise çok önemli bir değişim olmadığı belirlenmiştir.Öğe Wettability and roughness characteristics of modified wood boards using a hot-press(Elsevier Science Bv, 2011) Ünsal, Öner; Candan, Zeki; Korkut, SüleymanThe aim of this study was to investigate the effect of the thermal modification process by hot-press on the wettability and surface roughness characteristics of the eucalyptus wood boards. The roughness measurements, average roughness (R(a)), and maximum roughness (R(max)) were taken both parallel and perpendicular to the grain using a fine stylus tracing technique. Contact angle measurements were obtained using a goniometer system connected to a digital camera and computer system. The results showed that surface roughness values of the modified wood boards using a hot-press significantly decreased with increasing press pressure and with decreasing temperature. The contact angle measurements indicated that the thermal modification had a significant influence on the surface wettability of the wood boards. Statistical analyses showed significant differences in the surface roughness and contact angle values of the wood boards following thermal modification. The results acquired in this work provide important information for future research and utilization of the thermally modified wood boards. (C) 2011 Elsevier B.V. All rights reserved.Öğe Wettability and surface roughness of thermally modified plywood panels(Elsevier Science Bv, 2012) Candan, Zeki; Büyüksarı, Ümit; Korkut, Süleyman; Ünsal, Öner; Çakıcıer, NevzatThe objective of this research was to investigate the wettability and surface roughness properties of the plywood panels under thermal modification. The plywood panel specimens were subjected to thermal modification under atmospheric pressure and presence of air at a temperature of 150, 170 or 190 degrees C for 60 min. The contact angle measurements were obtained by using a KSV Cam-101 Scientific Instrument connected with a digital camera and computer system. The roughness measurements, average roughness (R-a) and maximum roughness (R-max), were performed based on both parallel and perpendicular to the grain using a fine stylus tracing technique. Statistical analyses showed significant differences in the surface roughness and contact angle values of the plywood panels following thermal modification. (C) 2011 Elsevier B.V. All rights reserved.Öğe Yield Change Based on the Diameter and Length in Beech (Fagus orientalis Lipsky)(Düzce Üniversitesi, 2008) Korkut, Süleyman; Kantay, Ramazan; Ünsal, ÖnerIn this study; it is determined that quantitative yield have obtained with sawingof 60-80 mm thickness unedged lumbers and 22-30 mm thickness slab boards with livesaw method of 3rd quality class logs obtained from Beech (Fagus orientalis Lipsky)that is commonly worked up and used a tree species in the lumber industry in Turkey.The logs used in the experiments have chosen among the logs-length 2m, 4m and 6m,midle-diameter 20 cm, 40 cm, 60 cm and 80 cm, taper %3- available in the log yards ofthe ORUS Duzce Lumber Factory.As a result, the mean lumber quantitative yield in 20cm, 40cm, 60cm and 80cmdiameter classes, 2m length logs are %66.93, %78.93, %80.1 and %79.77; in 4m lengthlogs are %61.1, %71.73, %75.77 and %75.93; in 6m length logs are %61.7, %75.17,%79.7 and %79.53 respectively.Acording to the results, while log length increases, quantitative yield decreasesin all diameter classes. Yield values increase depend on the increase of log diameter in20 cm, 40 cm and 60 cm diameter class. However, it is undertood that the increasingdoesn’t continue in 80 cm diameter class.
