CELİL ATİK - Academia.edu (original) (raw)
Papers by CELİL ATİK
Journal of the Faculty of Forestry Istanbul University, 1999
Esmer kraft selülozunun ağartılması sırasında meydana gelen kimyasal ve optik değişiklikler son ü... more Esmer kraft selülozunun ağartılması sırasında meydana gelen kimyasal ve optik değişiklikler son ürün olan kağıdın kalitesi üzerine önemli bir etki yapmaktadır. Araştırmada, esmer selülozdan başlayarak her bir ağartma basamağından alman hamurlarda, selüloz makromolekülündeki parçalan maları gösteren polimerizasyon derecesi tayini, ayrıca hamurun rengi ve ka litesi üzerine büyük etkisi olan lignin, kalıntı ve asitte çözünür lignin olarak belirlenmiştir. Bu verilerden, esmer selülozdan itibaren bütün ağartma ba samaklarında hamurların DP değerlerindeki önemli azalmaların yanı sıra kalıntı ve çözünür lignin değerlerinde de belirgin düşüşler görülmüştür. Selülozun optik niteliklerini iyileştirmeye de yarayan ağartma işleminde, ba samakların her birinden alınan hamurlarda parlaklık, beyazlık, k/s, opaklık ve renk gibi optik özelikler tespit edilerek ağartmanın ne derece gerçekleştiği saptanmıştır.
DOAJ (DOAJ: Directory of Open Access Journals), 2013
The goal of this study was to determine the effects of thermal modification and hot-pressing on t... more The goal of this study was to determine the effects of thermal modification and hot-pressing on the colour characteristics of pine wood as bio-resource. The experimental wood boards with dimensions of 250 mm in width by 500 mm in length by 18 mm in thickness were thermally compressed at a temperature of 120 ºC or 150 ºC, press pressure of 5 or 7 MPa for 60 min in a hot press. Results obtained in this study showed that the colour characteristics of the pine wood boards were affected by press pressure and temperature. The resin leakages significantly increased the chromacity (a*-25.99 and b*-43.18) of the treated wood samples. Thermally compressing caused browning of wood colour, which rate increases with pressure at high temperature conditions.
European Journal of Vascular and Endovascular Surgery, 2014
The aim of this study was to investigate the effects of the vasodilating b-blocker nebivolol and ... more The aim of this study was to investigate the effects of the vasodilating b-blocker nebivolol and the cardioselective b-blocker metoprolol on nitric oxide levels at vascular graft endothelium and vasa vasorum compared to controls in patients undergoing coronary artery bypass graft surgery. According to our results, we think that nebivolol may be safer and preferable in order to diminish graft spasm in patients undergoing coronary artery bypass graft surgery due to the nitric oxide-mediated vasodilating effect. Objectives: The aim of this study was to investigate the effects of the vasodilating b-blocker nebivolol and the cardioselective b-blocker metoprolol on nitric oxide (NO) levels at vascular graft endothelium and vasa vasorum compared to controls in patients undergoing coronary artery bypass graft surgery. Methods: This was a prospective study. Fifty-five patients were divided into three groups: nebivolol group (group N, n ¼ 23), metoprolol group (group M, n ¼ 16), and control group (group A, n ¼ 16). Group N received nebivolol 5 mg once daily, and group M received metoprolol 50 mg once daily for 15 days in the preoperative period. Control patients did not use b-blocker therapy. Tissue samples of both left internal mammary artery (LIMA) and saphenous vein grafts were investigated for NO activity using immunohistochemical methods. Results: Demographic characteristics and risk factors were similar between groups. We observed the highest NO activity in group N in both endothelial and vasa vasorum samples of LIMA and saphenous veins. NO activity of metoprolol group was similar to controls. Conclusions: According to our results, we think that nebivolol may be safer and preferable in order to diminish graft spasm in patients undergoing coronary artery bypass graft surgery due to the NO-mediated vasodilating effect.
Nordic Pulp & Paper Research Journal
Paper has been used in the field of hygiene for centuries. Tissue papers have low grammage, crepe... more Paper has been used in the field of hygiene for centuries. Tissue papers have low grammage, creped or non-creped surface, and consisting of one or more layers from virgin papers. Toilet paper, which has an important area of use, comes at the beginning of the tissue papers divided into various product groups. Its use has increased even more with the effect of the coronavirus pandemic. Increasing use of toilet paper causes clogging in sewers as solid waste. Because an important and large part of the sewage is composed of cellulosic structures. Therefore, the disintegration of toilet paper is an important issue. The main properties of toilet paper are characterized by grammage, thickness, polymerization degree, softness and wet tensile strength. This study, it was aimed to determine the relationship between the degree of polymerization, thickness, grammage, softness and wet tension strength of toilet papers, which accumulate in the sewer pipes and cause clogging, and their disintegrati...
İstanbul üniversitesi orman fakültesi dergisi, 2001
Effect of cellulase treatment of long fiber fraction on strength properties of recycled corrugate... more Effect of cellulase treatment of long fiber fraction on strength properties of recycled corrugated medium
BioResources, 2020
This study aimed to determine the influence of prehydrolysis of wood chips on the kraft pulping o... more This study aimed to determine the influence of prehydrolysis of wood chips on the kraft pulping of Populus x euramericana. Optimum cooking conditions were determined by evaluating different alkali concentrations and cooking periods. Xylanase was used to hydrolyze chips before cooking. Prehydrolysis process increased the yield and viscosity of pulp. Consequently, the mechanical properties of paper changed remarkably. In contrast, the optical properties of the unbleached kraft pulp declined due to lignin content.
Journal of the Faculty of Forestry Istanbul University, 1992
Hasılat tabloları düzenlem ek için gerekli olan veriler sabit veya geçici örnek alanlardan sağlan... more Hasılat tabloları düzenlem ek için gerekli olan veriler sabit veya geçici örnek alanlardan sağlanm aktadır. Örnek alanlarda yapılan ölçm e ve gözlem lerin de ğerlendirilm esi hasılat tablosunun düzenlenm esinde önemli bir yer tutmaktadır. Bu alanlardan elde edilen veriler yardım ıyla m eşcere parametrelerinin hassas olarak saptanm ası hasılat tablosunun daha sağlıklı hazırlanması anlam ına gel m ektedir. Bu çalışm a ile Türkiye orm anlarında herhangi bir ağaç türünden oluşan aynı yaşlı bir meşcereden alınan örnek alanda ölçülen çap ve boy değerle ri ve ilgili hacim denklem leri kullanılarak o örnek alana ait ihtiyaç duyulan m eş cere karakteristiklerinin elde edilmesini sağlayan bir bilgisayar programı hazır lanmıştır. Bu programın tanıtımı ve kullanılmasına ilişkin açıklamalar buradaki sayfa sınırlam ası nedeniyle ikinci bir makalede ele alınmıştır. 1) İ.Ü. Orman Fakültesi.Orman Amenajmanı Anabilim Dalı. 2) İ.Ü. Orman Fakültesi, Orman Ürünleri Kimyası ve Teknolojisi Anabilim Dalı. Y ayın K o m isy o n u n a S u n u ld u ğ u T a rih : 27.02.1996
Journal of the Faculty of Forestry Istanbul University, 2001
Farkli pisirme yontemleri ile Titrek Kavak’tan (Populus tremula L.) yuksek verimli kagit hamuru e... more Farkli pisirme yontemleri ile Titrek Kavak’tan (Populus tremula L.) yuksek verimli kagit hamuru elde etme olanaklari
Journal of the Faculty of Forestry Istanbul University, 1995
: Due to the decreasing limited forest resources, the increasing paper consumption and the pressu... more : Due to the decreasing limited forest resources, the increasing paper consumption and the pressure from the environmental movements, the recycled fibre has become increasingly important. Today’s modern paper and paperboard industry is the exclusive user of recycled fibre as a raw material. On the other hand, the recycled fibre inevitably presents a number of new challenges to the paper industry, as the recycled fibres are drained more slowly, often contaminated with other materials and fibre strength is diminished with the recycling number. Microbial growth is another common problem in the papermaking system. Besides the use of recycled fibre in paper and paperboard mills, the increased closure of the water and the conversion to neutral/alkaline systems exacerbate microbiological problems and decrease mill performances. Problems caused by micro organisms that are typically encountered in paper making systems include slime spots and holes, offensive odours, corrosion, paper breaks, brightness loss, additive spoilage, and shower and stock line plugging. These problems are costly because they lead to poor runnability, low production rates, off-quality paper, and even shortened equipment life due to accelerated corrosion rates. Microbiological growth control has therefore become more and more important within the paper industry. The proper control of microbiological growth involves properly identifying the problem and finding the best solution.
In biopulping researches fungal inoculum preparation have a significant role. In this study addit... more In biopulping researches fungal inoculum preparation have a significant role. In this study addition of com steep liquor (CSL) as a nutrient in inoculum growth medium was investigated. Flasks and petri plates containing potato dextrose yeast (PDY) and PDY+CSL were inoculated with two strainsof white rot fungus Ceriporiopsis subvermispora and maintained at 2TC. Productivity of PDY+CSL medium was higher than PDY medium in both dish flasks and petri plates. The highest productivity of 15 mg/mL and 17 mg/mL for FP 90031 -spand CZ-3 strains respectively was observed in PDY+CSL petri plate culture. Small 4.5 mm inoculum plugs alsa indicated high productivity for both strains.
Journal of the Faculty of Forestry Istanbul University, 2002
Journal of the Faculty of Forestry Istanbul University, 1999
Journal of the Faculty of Forestry Istanbul University, 2001
Turkiye'de yetisen endustriyel onem sahip agaclarin temel kimlik bilgileri ve kullanima yonel... more Turkiye'de yetisen endustriyel onem sahip agaclarin temel kimlik bilgileri ve kullanima yonelik genel degerlendirme
Journal of the Faculty of Forestry Istanbul University, 2001
Turkiye'de yetisen endustriyel oneme sahip agaclarin anatomik , fiziksel, mekanik ve kimyasal... more Turkiye'de yetisen endustriyel oneme sahip agaclarin anatomik , fiziksel, mekanik ve kimyasal ozellikleri
Journal of the Faculty of Forestry Istanbul University, 2006
Mobilya, kapi, yer kaplamasi gibi urunlerin en onemli kalite degerlendirme kriterlerinden birisi ... more Mobilya, kapi, yer kaplamasi gibi urunlerin en onemli kalite degerlendirme kriterlerinden birisi yuzeyinin rengidir. Bununla birlikte odun tekduze bir yapida degildir, bu nedenle de yuzey teksturu gorsel algilamayi etkilemektedir. Daginik aydinlatma kullanan cihazlar belli acidan aydinlatma kullanan cihazlarin eksigini gidermektedir. Bu calismada mese odununun farkli strukturel alanlari birbirine dik iki farkli konumda daginik aydinlatma kullanarak CIE L*a*b* renk degerleri belirlenmistir. Oz isini alanlarina kiyasla lif alanlarinin konumlanmaya daha hassas oldugu belirlenmistir. Ayrica mese odununun farkli alanlari arasinda renk farki degerleri 20’nin ustundedir. Bu nedenle renge dayali odunun karsilastirilma ve siniflandirilma islemleri cok dikkatli yapilmalidir.
Journal of the Faculty of Forestry Istanbul University, 1999
Esmer kraft selülozunun ağartılması sırasında meydana gelen kimyasal ve optik değişiklikler son ü... more Esmer kraft selülozunun ağartılması sırasında meydana gelen kimyasal ve optik değişiklikler son ürün olan kağıdın kalitesi üzerine önemli bir etki yapmaktadır. Araştırmada, esmer selülozdan başlayarak her bir ağartma basamağından alman hamurlarda, selüloz makromolekülündeki parçalan maları gösteren polimerizasyon derecesi tayini, ayrıca hamurun rengi ve ka litesi üzerine büyük etkisi olan lignin, kalıntı ve asitte çözünür lignin olarak belirlenmiştir. Bu verilerden, esmer selülozdan itibaren bütün ağartma ba samaklarında hamurların DP değerlerindeki önemli azalmaların yanı sıra kalıntı ve çözünür lignin değerlerinde de belirgin düşüşler görülmüştür. Selülozun optik niteliklerini iyileştirmeye de yarayan ağartma işleminde, ba samakların her birinden alınan hamurlarda parlaklık, beyazlık, k/s, opaklık ve renk gibi optik özelikler tespit edilerek ağartmanın ne derece gerçekleştiği saptanmıştır.
DOAJ (DOAJ: Directory of Open Access Journals), 2013
The goal of this study was to determine the effects of thermal modification and hot-pressing on t... more The goal of this study was to determine the effects of thermal modification and hot-pressing on the colour characteristics of pine wood as bio-resource. The experimental wood boards with dimensions of 250 mm in width by 500 mm in length by 18 mm in thickness were thermally compressed at a temperature of 120 ºC or 150 ºC, press pressure of 5 or 7 MPa for 60 min in a hot press. Results obtained in this study showed that the colour characteristics of the pine wood boards were affected by press pressure and temperature. The resin leakages significantly increased the chromacity (a*-25.99 and b*-43.18) of the treated wood samples. Thermally compressing caused browning of wood colour, which rate increases with pressure at high temperature conditions.
European Journal of Vascular and Endovascular Surgery, 2014
The aim of this study was to investigate the effects of the vasodilating b-blocker nebivolol and ... more The aim of this study was to investigate the effects of the vasodilating b-blocker nebivolol and the cardioselective b-blocker metoprolol on nitric oxide levels at vascular graft endothelium and vasa vasorum compared to controls in patients undergoing coronary artery bypass graft surgery. According to our results, we think that nebivolol may be safer and preferable in order to diminish graft spasm in patients undergoing coronary artery bypass graft surgery due to the nitric oxide-mediated vasodilating effect. Objectives: The aim of this study was to investigate the effects of the vasodilating b-blocker nebivolol and the cardioselective b-blocker metoprolol on nitric oxide (NO) levels at vascular graft endothelium and vasa vasorum compared to controls in patients undergoing coronary artery bypass graft surgery. Methods: This was a prospective study. Fifty-five patients were divided into three groups: nebivolol group (group N, n ¼ 23), metoprolol group (group M, n ¼ 16), and control group (group A, n ¼ 16). Group N received nebivolol 5 mg once daily, and group M received metoprolol 50 mg once daily for 15 days in the preoperative period. Control patients did not use b-blocker therapy. Tissue samples of both left internal mammary artery (LIMA) and saphenous vein grafts were investigated for NO activity using immunohistochemical methods. Results: Demographic characteristics and risk factors were similar between groups. We observed the highest NO activity in group N in both endothelial and vasa vasorum samples of LIMA and saphenous veins. NO activity of metoprolol group was similar to controls. Conclusions: According to our results, we think that nebivolol may be safer and preferable in order to diminish graft spasm in patients undergoing coronary artery bypass graft surgery due to the NO-mediated vasodilating effect.
Nordic Pulp & Paper Research Journal
Paper has been used in the field of hygiene for centuries. Tissue papers have low grammage, crepe... more Paper has been used in the field of hygiene for centuries. Tissue papers have low grammage, creped or non-creped surface, and consisting of one or more layers from virgin papers. Toilet paper, which has an important area of use, comes at the beginning of the tissue papers divided into various product groups. Its use has increased even more with the effect of the coronavirus pandemic. Increasing use of toilet paper causes clogging in sewers as solid waste. Because an important and large part of the sewage is composed of cellulosic structures. Therefore, the disintegration of toilet paper is an important issue. The main properties of toilet paper are characterized by grammage, thickness, polymerization degree, softness and wet tensile strength. This study, it was aimed to determine the relationship between the degree of polymerization, thickness, grammage, softness and wet tension strength of toilet papers, which accumulate in the sewer pipes and cause clogging, and their disintegrati...
İstanbul üniversitesi orman fakültesi dergisi, 2001
Effect of cellulase treatment of long fiber fraction on strength properties of recycled corrugate... more Effect of cellulase treatment of long fiber fraction on strength properties of recycled corrugated medium
BioResources, 2020
This study aimed to determine the influence of prehydrolysis of wood chips on the kraft pulping o... more This study aimed to determine the influence of prehydrolysis of wood chips on the kraft pulping of Populus x euramericana. Optimum cooking conditions were determined by evaluating different alkali concentrations and cooking periods. Xylanase was used to hydrolyze chips before cooking. Prehydrolysis process increased the yield and viscosity of pulp. Consequently, the mechanical properties of paper changed remarkably. In contrast, the optical properties of the unbleached kraft pulp declined due to lignin content.
Journal of the Faculty of Forestry Istanbul University, 1992
Hasılat tabloları düzenlem ek için gerekli olan veriler sabit veya geçici örnek alanlardan sağlan... more Hasılat tabloları düzenlem ek için gerekli olan veriler sabit veya geçici örnek alanlardan sağlanm aktadır. Örnek alanlarda yapılan ölçm e ve gözlem lerin de ğerlendirilm esi hasılat tablosunun düzenlenm esinde önemli bir yer tutmaktadır. Bu alanlardan elde edilen veriler yardım ıyla m eşcere parametrelerinin hassas olarak saptanm ası hasılat tablosunun daha sağlıklı hazırlanması anlam ına gel m ektedir. Bu çalışm a ile Türkiye orm anlarında herhangi bir ağaç türünden oluşan aynı yaşlı bir meşcereden alınan örnek alanda ölçülen çap ve boy değerle ri ve ilgili hacim denklem leri kullanılarak o örnek alana ait ihtiyaç duyulan m eş cere karakteristiklerinin elde edilmesini sağlayan bir bilgisayar programı hazır lanmıştır. Bu programın tanıtımı ve kullanılmasına ilişkin açıklamalar buradaki sayfa sınırlam ası nedeniyle ikinci bir makalede ele alınmıştır. 1) İ.Ü. Orman Fakültesi.Orman Amenajmanı Anabilim Dalı. 2) İ.Ü. Orman Fakültesi, Orman Ürünleri Kimyası ve Teknolojisi Anabilim Dalı. Y ayın K o m isy o n u n a S u n u ld u ğ u T a rih : 27.02.1996
Journal of the Faculty of Forestry Istanbul University, 2001
Farkli pisirme yontemleri ile Titrek Kavak’tan (Populus tremula L.) yuksek verimli kagit hamuru e... more Farkli pisirme yontemleri ile Titrek Kavak’tan (Populus tremula L.) yuksek verimli kagit hamuru elde etme olanaklari
Journal of the Faculty of Forestry Istanbul University, 1995
: Due to the decreasing limited forest resources, the increasing paper consumption and the pressu... more : Due to the decreasing limited forest resources, the increasing paper consumption and the pressure from the environmental movements, the recycled fibre has become increasingly important. Today’s modern paper and paperboard industry is the exclusive user of recycled fibre as a raw material. On the other hand, the recycled fibre inevitably presents a number of new challenges to the paper industry, as the recycled fibres are drained more slowly, often contaminated with other materials and fibre strength is diminished with the recycling number. Microbial growth is another common problem in the papermaking system. Besides the use of recycled fibre in paper and paperboard mills, the increased closure of the water and the conversion to neutral/alkaline systems exacerbate microbiological problems and decrease mill performances. Problems caused by micro organisms that are typically encountered in paper making systems include slime spots and holes, offensive odours, corrosion, paper breaks, brightness loss, additive spoilage, and shower and stock line plugging. These problems are costly because they lead to poor runnability, low production rates, off-quality paper, and even shortened equipment life due to accelerated corrosion rates. Microbiological growth control has therefore become more and more important within the paper industry. The proper control of microbiological growth involves properly identifying the problem and finding the best solution.
In biopulping researches fungal inoculum preparation have a significant role. In this study addit... more In biopulping researches fungal inoculum preparation have a significant role. In this study addition of com steep liquor (CSL) as a nutrient in inoculum growth medium was investigated. Flasks and petri plates containing potato dextrose yeast (PDY) and PDY+CSL were inoculated with two strainsof white rot fungus Ceriporiopsis subvermispora and maintained at 2TC. Productivity of PDY+CSL medium was higher than PDY medium in both dish flasks and petri plates. The highest productivity of 15 mg/mL and 17 mg/mL for FP 90031 -spand CZ-3 strains respectively was observed in PDY+CSL petri plate culture. Small 4.5 mm inoculum plugs alsa indicated high productivity for both strains.
Journal of the Faculty of Forestry Istanbul University, 2002
Journal of the Faculty of Forestry Istanbul University, 1999
Journal of the Faculty of Forestry Istanbul University, 2001
Turkiye'de yetisen endustriyel onem sahip agaclarin temel kimlik bilgileri ve kullanima yonel... more Turkiye'de yetisen endustriyel onem sahip agaclarin temel kimlik bilgileri ve kullanima yonelik genel degerlendirme
Journal of the Faculty of Forestry Istanbul University, 2001
Turkiye'de yetisen endustriyel oneme sahip agaclarin anatomik , fiziksel, mekanik ve kimyasal... more Turkiye'de yetisen endustriyel oneme sahip agaclarin anatomik , fiziksel, mekanik ve kimyasal ozellikleri
Journal of the Faculty of Forestry Istanbul University, 2006
Mobilya, kapi, yer kaplamasi gibi urunlerin en onemli kalite degerlendirme kriterlerinden birisi ... more Mobilya, kapi, yer kaplamasi gibi urunlerin en onemli kalite degerlendirme kriterlerinden birisi yuzeyinin rengidir. Bununla birlikte odun tekduze bir yapida degildir, bu nedenle de yuzey teksturu gorsel algilamayi etkilemektedir. Daginik aydinlatma kullanan cihazlar belli acidan aydinlatma kullanan cihazlarin eksigini gidermektedir. Bu calismada mese odununun farkli strukturel alanlari birbirine dik iki farkli konumda daginik aydinlatma kullanarak CIE L*a*b* renk degerleri belirlenmistir. Oz isini alanlarina kiyasla lif alanlarinin konumlanmaya daha hassas oldugu belirlenmistir. Ayrica mese odununun farkli alanlari arasinda renk farki degerleri 20’nin ustundedir. Bu nedenle renge dayali odunun karsilastirilma ve siniflandirilma islemleri cok dikkatli yapilmalidir.