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Öğe Classification of wood species grown in Turkey according to some physico-mechanic properties(Istanbul Univ, Fac Forestry, 2016) As, Nusret; Dündar, Türker; Büyüksarı, ÜmitClassgroupsformedon the basis ofphysico-mechanical values, and the distribution ofgrown in Turkeytree species havebeen made in these classes. In classification, air dry12-15% density, shrinkage, bending strength, modulus of elasticity in bending, impactbending, compression, tensile, cleavage, shearingstrength and hardnessvalues were used.Öğe Comparison of Micro- and Standard-Size Specimens in Evaluating the Flexural Properties of Scots Pine Wood(North Carolina State Univ Dept Wood & Paper Sci, 2016) Büyüksarı, Ümit; As, Nusret; Dündar, Türker; Sayan, EzelThe aim of this study was to investigate the flexural properties (bending strength and modulus of elasticity) of Scots pine wood (Pinus sylvestris L.) using micro-and standard-size test specimens. In the standard-and micro-size specimens, the average bending strengths were evaluated as 72.8 and 62.4 MPa, and the bending modulus of elasticity was 9917 and 2884 MPa, respectively. These results showed that the bending strength and modulus of elasticity values of the micro-size specimens were lower than those of the standard-size specimens. The statistically significant effects included the specimen size, individual trees, and the interactions of the specimen size and trees on the bending strength and modulus of elasticity. Furthermore, regression analyses indicated a positive linear regression between the flexural properties of the micro-and standard-size specimens. The results indicated that micro-size specimens can be used to estimate the flexural properties of Scots pine wood when obtaining standard-size specimens is not possible.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 boron and phosphate compounds on physical, mechanical, and fire properties of wood-polypropylene composites(Elsevier Sci Ltd, 2012) Ayrılmış, Nadir; Akbulut, Turgay; Dündar, Türker; White, Robert H.; Mengeloğlu, Fatih; Büyüksarı, Ümit; Avcı, ErkanPhysical, mechanical, and fire properties of the injection-molded wood flour/polypropylene composites incorporated with different contents of boron compounds; borax/boric acid and zinc borate, and phosphate compounds; mono and diammonium phosphates were investigated. The effect of the coupling agent content, maleic anhydride-grafted polypropylene, on the properties of the composites with fire-retardant was also investigated. The composites with the zinc borate had the highest dimensional stability and strength in the bending, tensile, and izod impact, followed by the monoammonium phosphate, borax/boric acid, and diammonium phosphate treatments. The treatments produced modest improvements in fire performance as indicated by reductions in the heat release rates. Best results were achieved with the phosphate treatments. The Scanning Electron Microscope-Energy Dispersive Spectroscopy elemental mapping of the samples revealed that the outer surface of the wood fibers was coated by some crystalline deposits of the fire-retardants. (C) 2012 Elsevier Ltd. All rights reserved.Öğe EFFECT OF HEAT TREAMENT ON THE PHYSICAL AND MECHANICAL PROPERTIES OF COMPRESSION AND OPPOSITE WOOD OF BLACK PINE(North Carolina State Univ Dept Wood & Paper Sci, 2012) Dündar, Türker; Büyüksarı, Ümit; Avcı, Erkan; Akkılıç, HüseyinThe effect of commercial heat treatment on physical and mechanical properties of compression wood (CW) and opposite wood (OW) of black pine (Pinus nigra Arnold) was investigated. Black pine logs containing CW were cut parallel to the pith and separated into CW and OW sections. A commercial heat treatment process was applied to pine lumber at 180 and 210 degrees C for 3 hours. Water absorption (WA), contact angle (CA), swelling, modulus of rupture (MOR), modulus of elasticity (MOE), and impact bending strength (IBS) were measured. The results showed that heat treatment decreased water absorption and swelling of the CW and OW of black pine. Heat treatment at 210 degrees C temperature decreased the longitudinal swelling of CW by 51.4%. Higher immersion time lowered the effect of heat treatment on the WA values. The CA values of the CW and OW increased due to heat treatment. Heat treatment reduced the MOR, MOE, and IBS values. The results indicated that MOR, MOE, and CA values were highly affected in the CW; on the other hand, the IBS value was highly affected in the OW by heat treatment compared to control groups. The results indicate that heat-stabilized CW can be used more widely and effectively in the forest products industry.Öğe The effects of heat treatment on some technological properties of Scots pine (Pinus sylvestris L.) wood(Elsevier Sci Ltd, 2008) Korkut, Süleyman; Akgül, Mehmet; Dündar, TürkerHeat treatment is often applied to wood species to improve their dimensional stability. This study examined the effect of heat treatment on certain mechanical properties of Scots pine (Pinus sylvestris L.), which has industrially high usage potential and large plantations in Turkey. Wood specimens obtained from Bolu, Turkey, were subjected to heat treatment under atmospheric pressure at varying temperatures (120, 150 and 180 degrees C) for varying durations (2, 6 and 10 h). The test results of heat-treated Scots pine and control samples showed that technological properties including compression strength, bending strength, modulus of elasticity in bending, janka-hardness, impact bending strength and tension strength perpendicular to grain suffered with heat treatment, and increase in temperature and duration further diminished technological strength values of the wood specimens. (C) 2007 Elsevier Ltd. All rights reserved.Öğe The effects of some manufacturing factors on surface roughness of sliced Makore (Tieghemella heckelii Pierre Ex A.Chev.) and rotary-cut beech (Fagus orientalis L.) Veneers(Pergamon-Elsevier Science Ltd, 2008) Dündar, Türker; Akbulut, Turgay; Korkut, SüleymanIn this study, the effects of veneer thickness, cutting speed, knife bevel, vertical and horizontal opening, and drying temperature on surface roughness of sliced Makore veneer and rotary-cut beech veneer were evaluated. Makore logs for sliced veneers and beech logs were used for rotary-cut veneers manufacturing. Before veneer manufacturing, the Makore and beech logs were steamed indirectly at 80 degrees C for 50 and 36h, respectively. Roughness measurements were conducted according to DIN standard 4768 by using stylus profilometer. The sliced radial and tangential veneers were grouped and evaluated separately. Results showed that veneer thickness, cutting speed and knife bevel had a significant effect on surface roughness for the sliced veneers, but veneer drying temperature did not affect significantly the surface roughness. In general, surface roughness of the veneer increases with increasing veneer thickness. However, increases in cutting speed decreased the surface roughness. The most suitable knife bevel was 17.5 degrees for manufacturing sliced veneers from Makore. For rotary-cut veneers, vertical and horizontal opening had a significant effect on the surface roughness. The results indicated that vertical opening should be about 50% and horizontal opening about 80-90% of veneer thickness to minimize the surface roughness in manufacturing rotary cut veneer from oriental beech. (c) 2007 Elsevier Ltd. All rights reserved.Öğe Intra-Ring Properties of Earlywood and Latewood Sections of Sessile Oak (Quercus petraea) Wood(North Carolina State Univ Dept Wood & Paper Sci, 2018) Büyüksarı, Ümit; As, Nusret; Dündar, TürkerStrength attributes of isolated microscopic sections of earlywood (EW) and latewood (LW) tissues are evaluated for sessile oak (Quercus petraea). The properties measured at the micro-scale were then used to estimate the macroscopic strength characteristics of the wood. The bending strength, modulus of elasticity (MOE) in bending, and tensile strength of EW and LW sections were determined. The EW and LW ring width, annual ring width, and LW proportion were also determined. The estimated values were calculated using the EW and LW mechanical properties and LW proportions, while the measured values were determined using standard-sized test samples. The LW sections had higher values than the EW sections for all measured mechanical properties. The average EW and LW widths and LW proportion were 0.50 mm, 0.49 mm, and 49.3%, respectively. The estimated bending strength, MOE, and tensile strength values were 80.1 MPa, 2831.7 MPa, and 112.1 MPa, respectively. The estimated bending strength and MOE values were lower than the measured values, while the estimated tensile strength values were higher than the measured values.Öğe Mechanical Properties of Earlywood and Latewood Sections of Scots Pine Wood(North Carolina State Univ Dept Wood & Paper Sci, 2017) Büyüksarı, Ümit; As, Nusret; Dündar, TürkerThe aim of this study was to determine the mechanical properties of earlywood (EW) and latewood (LW) sections of Scots pine (Pinus sylvestris L.) wood, and determine the relationship between calculated and measured values. The bending strength, modulus of elasticity in bending, and the tensile strength of EW and LW sections were determined. The mechanical properties were calculated using EW and LW mechanical properties and LW proportion. Also, mechanical properties were determined in standard size samples and compared to the calculated properties. In earlywood and latewood sections, the bending strength was 37.3 MPa and 93.9 MPa, the modulus of elasticity in bending was 1557.6 MPa and 3600.4 MPa, and the tensile strength was 58.6 MPa and 189.6 MPa, respectively. The results showed that the LW section had higher mechanical properties than those of the EW section for all of the measured mechanical properties. The calculated bending strength, modulus of elasticity, and tensile strength values were 53.3 MPa, 2133.7 MPa, and 95.5 MPa, respectively. The calculated bending strength and modulus of elasticity values were lower compared to the measured values, while the calculated tensile strength values were higher than that of the measured values.Öğe MICRO-MECHANICAL PROPERTIES OF OAK WOOD AND COMPARISON WITH STANDARD-SIZED SAMPLES(Univ Bio-Bio, 2017) Büyüksarı, Ümit; As, Nusret; Dündar, Türker; Korkmaz, OgünThe aim of this study was to investigate micro-mechanical properties of Oak (Quercus petraea) wood and to compare with standard-size test specimens values. Bending strength, modulus of elasticity in bending, compression strength and tensile strength were determined using micro-and standard-size mechanical test samples. In the micro- and standard size samples, bending strengths were evaluated as 71,2 MPa and 99,4 MPa, modulus of elasticity in bending as 2741,3 MPa and 11394,1 MPa tensile strengths as 98,7 MPa and 93,8 MPa and compression strengths as 45,4 MPa and 46,6 MPa respectively. The results showed that the bending strength, modulus of elasticity and compression strength of the micro-size samples were lower compared to the standard-size samples, while the tensile strength was higher in the micro-size samples. The compression strength values of micro-and standard-size samples were not significantly different. The regression analyses indicated a positive linear regression between the mechanical properties of micro-and standard-size samples. Micro-size specimens can be used to estimate the mechanical properties of Oak wood when obtaining standard-size specimens is not possible.Öğe Micro-Tensile and Compression Strength of Scots Pine Wood and Comparison with Standard-Size Test Results(Zagreb Univ, Fac Forestry, 2017) Büyüksarı, Ümit; As, Nusret; Dündar, Türker; Sayan, EzelThe goal of this study was to investigate the tensile and compression strength of Scots pine wood (Pinus sylvestris L.) using micro- and standard-sized test specimens. In the standard- and micro-sized specimens, tensile strength was evaluated as 76.9 MPa and 91.5 MPa and compression strength as 43.8 MPa and 36.3 MPa, respectively. The results showed that the compression strength of the micro- sized specimens was lower compared to the standard-sized specimens, while the tensile strength was higher in the micro- sized specimens. With the exception of the effect of specimen size and individual tree interaction on tensile strength, statistically significant effects were found for specimen size, individual trees and the interactions of the size and trees on the tensile and compression strength. Moreover, regression analyses indicated a positive linear regression between the strength of micro- and standard-sized specimens. Micro-sized specimens can be used to estimate the tensile and compression strength of Scots pine wood, when it is not possible to obtain standard-size specimens.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 Türkiye'de yetişen ağaç türlerinin bazı fiziko-mekanik özellikleri bakımından sınıflandırılması(2016) Büyüksarı, Ümit; Dündar, Türker; As, NusretTürkiye'de yetişen bazı ağaç türlerinin sahip oldukları Fiziko-mekanik değerler esas alınarak mevcut ya da oluşturulmuş bulunan sınıf gruplarına dağılımı yapılmıştır. Sınıflandırmada genelde belirlenmiş olan fiziksel özelliklerden hava kurusu % 12-15 yoğunluk, daralma, mekanik özelliklerden eğilme direnci, eğilmede elastikiyet modülü, dinamik eğilme, basınç, çekme, yarılma, makaslama dirençleri ve sertlik değerleri dikkate alınmıştır.
