Çağrı OLGUN

Dr. Çağrı OLGUN

Forest Industry Engineering, Kastamonu University, Kastamonu, Turkey (Türkiye)
orcid
Assoc. Prof., Kastamonu University, Department of Forest Ind...

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 July 2023 in Micromachines
Verified
Journal Article
Open access
PDF file
EDEkrem DURMAZ
Ekrem DURMAZ
SSSelva Sertkaya
Selva Sertkaya
HYHande Yilmaz
Hande Yilmaz
Çağrı OLGUNÇağrı OLGUN
Çağrı OLGUN
OOOrhan Ozcelik
Orhan Ozcelik
Zeki CandanZeki Candan
Zeki Candan
The rapid population growth, increasing global energy demand, climate change, and excessive use of fossil fuels have adversely affected environmental management and sustainability. Furthermore, the requirements for a safer ecology and environment have necessitated the use of renewable materials, thereby solving the problem of sustainability of resources. In this perspective, lignocellulosic biomass is an attractive natural resource because of its abundance, renewability, recyclability, and low cost. The ever-increasing developments in nanotechnology have opened up new vistas in sensor fabrication such as biosensor design for electronics, communication, automobile, optical products, packaging, textile, biomedical, and tissue engineering. Due to their outstanding properties such as biodegradability, biocompatibility, non-toxicity, improved electrical and thermal conductivity, high physical and mechanical properties, high surface area and catalytic activity, lignocellulosic bionanomaterials including nanocellulose and nanolignin emerge as very promising raw materials to be used in the development of high-impact biosensors. In this article, the use of lignocellulosic bionanomaterials in biosensor applications is reviewed and major challenges and opportunities are identified.

3 February 2015 in BioResources
Verified
Journal Article
Open access
PDF file
SASaim ATEŞ
Saim ATEŞ
MGMahmut Gür
Mahmut Gür
Osman Emre ÖzkanOsman Emre Özkan
Osman Emre Özkan
MAMehmet Akça
Mehmet Akça
Çağrı OLGUNÇağrı OLGUN
Çağrı OLGUN
AGAytaç Güder
Aytaç Güder
The total phenolic content (TPC), total flavonoid content (TFC), phenolic compounds, and antifungal activity of olive (Olea europaea var. sylvestris) and juniper (Juniperus foetidissima) sapwood and heartwood extractives were examined. The extractives were obtained using methanol solvents. The different compounds in extractives were identified and quantified. The antifungal activities of different parts of the olive and juniper wood extractives were determined in vitro. Pleurotus ostreatus mycelium was used for the antifungal activity experiment. Extractive compounds obtained from olive and juniper woods were found to be effective, natural antifungal agents.

26 August 2015 in Wood Material Science & Engineering
Verified
Journal Article
Closed access
SASaim ATEŞ
Saim ATEŞ
HKHasimet R. Kara
Hasimet R. Kara
Çağrı OLGUNÇağrı OLGUN
Çağrı OLGUN
Osman Emre ÖzkanOsman Emre Özkan
Osman Emre Özkan
This work investigated some mechanical, physical and free formaldehyde emission properties of heat-treated MDF. For this purpose, MDF panels were subjected to varying heat treatment temperatures (155°C, 165°C and 175°C), durations (2.5 h., 3.5 h. and 4.5 h.) and waiting times after hot pressing (30 min., 120 min. and 600 min). Thickness swelling (TS), water absorption (WA), free formaldehyde emission (FFE), bending strength (BS), modulus of elasticity (MOE), tensile strength perpendicular to fibers (TSPF) for treated and untreated samples were tested and evaluated statistically. Consequently, after the heat treatment values of tensile strength, bending strength and modulus of elasticity were almost negatively affected relatively, but the thickness swelling and water absorption and quantities of free formaldehyde were improved positively of MDF samples.

25 April 2023 in Forests
Verified
Journal Article
Open access
PDF file
Çağrı OLGUNÇağrı OLGUN
Çağrı OLGUN
SASaim ATEŞ
Saim ATEŞ
Lignin characteristics are significantly affected by kraft processing and isolation conditions. In the studies carried out in this context, commercial lignins or isolated lignins from industrial black solutions are generally preferred. In this study, in order to conduct more comprehensive research, three lignin samples were isolated from kraft black liquor obtained from laboratory cooking trials of pine, poplar, and wheat straw chips, representing softwoods, hardwoods, and annual plants, respectively, according to efficient pulping studies. In addition, another lignin-containing industrial waste was provided from a pulp mill (OBL). The acidification method was applied for isolating lignin from black liquor samples. After isolating the lignin samples from different sources, they were characterized and compared with the commercially available kraft lignin sample (Indulin AT). Total phenolic groups, carboxyl groups, purity, functional groups, nitrobenzene oxidation products, molecular weight, thermal stability, and element contents were analyzed. The isolated lignin samples (except wheat straw) were as pure as commercial lignin. Since the wheat straw was agricultural waste and an annual plant, inorganic elements such as P, K, and Si were more abundant than in the other samples. However, the polydispersity and molecular weight of all of the isolated lignin samples were higher than those of commercial lignin. Because the ash contents of the lignin samples for pine, poplar, OBL, and indulin AT were between 1 and 3%, they can be used for high-value applications. In particular, despite some disadvantages, wheat straw lignin has greater potential for use in extruders than softwood lignins due to their syringyl content.

25 July 2017 in Indian Journal of Pharmaceutical Education and Research
Verified
Journal Article
Open access
SÖSevil Özkinali
Sevil Özkinali
NŞNesrin Şener
Nesrin Şener
MGMahmut Gür
Mahmut Gür
KGKerim Güney
Kerim Güney
Çağrı OLGUNÇağrı OLGUN
Çağrı OLGUN

25 July 2017 in Indian Journal of Pharmaceutical Education and Research
Verified
Journal Article
Open access
Çağrı OLGUNÇağrı OLGUN
Çağrı OLGUN
Osman Emre ÖzkanOsman Emre Özkan
Osman Emre Özkan
BGBetül Güney
Betül Güney
EPEsma Sena Pattabanoglu
Esma Sena Pattabanoglu
KGKerim Güney
Kerim Güney
MGMahmut Gür
Mahmut Gür