Gokhan Gunduz

Bartın University, Faculty of Forestry, Department of Forest Inustrial Engineering, Faculty Member

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I like to understand and discover the simple and see the fascinating complex connection to the whole world.

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Türkiye’de Bazı Ağaç Türü Odunlarının Fiziksel Özellikleri Üzerine Yapılan Araştırmaların Değerlendirilmesi (Evaluation of Research Studies of Some Wood Species in Turkey)

In this study, the results of academic research about the physical properties of some wood speci... more In this study, the results of academic research about the physical properties of some wood species in Turkey between 1951-2015 were collected and evaluated. For this purpose, Journal of Turkish Forestry Research Institue, Turkish Journal of Agriculture and Forestry, Engineering Journals and masters and Ph. D. Thesises were investigated. Volume-weight-density relations, solid wood, acoustical and electrical properties were compared. The results are presented in detailed charts. The units were converted to N/mm2 for a easier comparision for readers.

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Physical, Morphological Properties and Raman Spectroscopy of Chestnut Blight Diseased Castanea Sativa Mill. Wood

by Gokhan Gunduz, Barbaros Yaman, and Deniz Aydemir

CERNE, 2016

In this study, some of the physical and anatomical properties of Chestnut Blight Diseased (CBD) w... more In this study, some of the physical and anatomical properties of Chestnut Blight Diseased (CBD) wood were investigated, and the study also included observations using Raman spectroscopy. The objective of these investigations was to determine the extent of the damage that is done to the wood of the diseased chestnut trees, which must be removed from the forest and used in the manufacture of industrial products. It was indicated that most of the adverse effects of the disease were in the vascular cambium. There was a clear indication of deterioration of the wood in the last growth ring next to vascular cambium. In the diseased secondary xylem region next to vascular cambium; vessel diameter, vessel frequency and vessel element length had a decrease, and vessel and other cells were irregular compared to healthy wood. Spores were detected and identified as Cryphonectria parasitica (Murrill). Annual ring properties (annual growth ring width, latewood percentage, etc.) were similar in diseased wood compared to healthy wood. The Raman spectroscopy results showed no significant changes in the structure of the cell wall or its components. After removing the diseased parts, unlimited usage of formerly wood is possible. Heat treatment of the wood is suggested before use in the interest of sanitation and dimensional stability.

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A22. Bioresources (Heat trt. wood, 6,2, 1308-1321, 2011)

Characterization and Element Analysis of Wood Pellets Obtained from Low-valued Types of Wood

by Gokhan Gunduz and Deniz Aydemir

Energy Sources Part A Recovery Utilization and Environmental Effects

Increasing environmental problems and unreliable energy supply from abroad are forcing various co... more Increasing environmental problems and unreliable energy supply from abroad are forcing various countries to identify clean ways to generate energy within their national boundaries. One approach that has been used for many years is the manufacture of wood pellets, and industry that uses logs as a source of ligno-cellulosic raw material as well as other wooden residues for the production of wood pellets. In this study, we compared the quality of wood pelletsobtained from several different raw materials, i.e., Rhododendron ponticum (Type 1), Laurusnobilis(Type 2), and Castanea sativa(Type 3). The quality of the wood pellets was characterized mainly by their bulk density, moisture content, ash content, volatiles, sulfur content in the ash, total sulfur content, heating values, elemental analysisof the ash, and chlorine content. The results showed that bulk density was similar for each type of pellet. In quality values, ash content and the sulfur content in the ash were found to be lower...

Natural Fillers-Filled Styrene Maleic Anhydride Copolymer Composites

by Gokhan Gunduz and Deniz Aydemir

Wood research

The aim of this study was to determine morphological characterization, mechanical properties and ... more The aim of this study was to determine morphological characterization, mechanical properties and thermal stability of natural fillers-filled styrene maleic anhydride (SMA) copolymer composites. SMA and cellulosic fillers including starch, α-cellulose, and ultra-fine cellulose (UFC) were used to manufacture composites in thermal melting mixer. The morphology of natural fillers-filled SMA composites was investigated by scanning electron microscopy (SEM). It was observed that natural fillers were dispersed within SMA matrix and there were some voids in the composites. It can be said that the voids occurred due to esterification reactions between matrix and fillers. Mechanical properties of the composites were determined with flexure test, tensile test and impact test. The results were showed that flexure and tensile strength and impact strength were decrease as adding the particles; whereas, both flexure and tensile modulus of elasticity (MOE) were increased to SMA/AC and then decrease...

Thermal Analysis of Micro- and Nano-Lignocellulosic Reinforced Styrene Maleic Anhydride Composite Foams

by Gokhan Gunduz and Deniz Aydemir

International Journal of Polymer Analysis and Characterization, 2015

ABSTRACT The aim of this study was to measure the thermal properties of foamed nano/macro filler ... more ABSTRACT The aim of this study was to measure the thermal properties of foamed nano/macro filler reinforced styrene maleic anhydride (SMA) composites. SMA (66%) as a polymer matrix (10% maleic anhydride content) and various fillers including: wood flour, starch, α-cellulose, microcrystalline cellulose or cellulose nano fibrils as reinforcing agents (30%) and lubricant (4%) were used to manufacture the composites in twin screw extruder. Dynamic mechanical thermal analysis (DMTA) analysis was done to determine the viscoelastic properties and glass transition temperature (Tg) of the composite foams. The analysis of loss modulus (E&#39;&#39;) allowed us to observe relaxation behavior of the foamed composites. Thermogravimetric analysis (TGA) was used to measure the thermal decomposition properties of the foamed composites. According to the TGA results, thermal degradation of all the foamed composites was found to be lower compared with pure SMA polymer composites. The storage modulus values were negatively affected with a second time foaming (re-processing (recycling) the initially processed composites a second time) and it can be said that same situation was similar for loss modulus and Tg, too. As results, second times foamed composite were lower than those of the foamed composites. According to the MFI test, viscosity of the SMA was found to be increase with the addition of fillers.

Influence of Micro- and Nanonatural Fillers on Mechanical and Physical Properties of Foamed SMA Composites

Polymer-Plastics Technology and Engineering, 2014

This study is to investigate the reinforcing effects of fillers on mechanical and physical proper... more This study is to investigate the reinforcing effects of fillers on mechanical and physical properties of foamed styrene-maleic anhydride (SMA) composites. According to the results, the best foaming was determined for starch reinforced SMA composite. The best result of expansion ratio was found as 22.75% to SMA/starch composites. Stereo light microscopy results demonstrated that the foamed cell distribution is heterogeneous and composed of two sections. The minimum density was found as 0.64 g/cm 3 for foamed SMA/starch composites. Mechanical properties of all foamed composites were found to be low as compared to neat SMA composite.

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The Silent Heroes: Effective Microorganisms

The importance of non-toxic food and non-polluted natural resources depends on a clean environmen... more The importance of non-toxic food and non-polluted natural resources depends on a clean environment. Effective microorganisms (EM) are a consortium of benefical microorganisms. These microorganisms change the balance from degeneration to regeneration. EM technology is widely used in agriculture, waste treatment and health. The application of EM technology can be integrated with standard agricultural fertilizers and reduces the usage of these chemicals. EM technology is non-toxic and cheap. Many studies are conducted about the effectiveness of EM technology and some of its results are critized. The critics are mostly related to wrong usage and application procedures. Education, training and good knowledge about microorganisms and its applications will provide more effective results in future.

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Morphological characterization of foamed natural filler-reinforced styrene maleic anhydride (SMA) composites

The aim of this study is to investigate the foaming of styrene maleic anhydride (SMA) matrix comp... more The aim of this study is to investigate the foaming of styrene maleic anhydride (SMA) matrix composites with a physical foaming agent, created during the reactive extrusion of natural fillers and SMA. The effect of lubricant on the foaming of SMA composites was also investigated. Whether particle’s crystallinity and hydroxyl number had any effect on cell size and cell density was also studied. The results showed that the greatest cell size and expansion occurred in the starch reinforced SMA composite which also exhibited the highest hydroxyl number and water by-product from reactive extrusion. Whereas microcrystalline cellulose-SMA composite exhibited the least cell number and expansion after extrusion because of the high crystallinity of MCC and the low hydroxyl number. Scanning electron microscopy results revealed that the cell distribution in foamed samples was heterogeneous and cell density increased from the core to skin layer. The results showed that hydroxyl number has an important effect on foaming and cell nucleation of the composites, and cell properties changed with filler’s percentage crystallinity.

Heat treated wood–nylon 6 composites

Heat treatment is a relatively benign modification method that is growing as an industrial proces... more Heat treatment is a relatively benign modification method that is growing as an industrial process to improve hygroscopicity, dimensional stability and biological resistance of lignocellulosic fillers. There also has been increased interest in the use of lignocellulosic fillers in numerous automotive applications.
This study investigated the influence of untreated and heat treated wood fillers on the mechanical and rheological properties of wood filled nylon 6 composites for possible under-the-hood applications in the automobile industry where conditions are too severe for commodity plastics to withstand. In this study, exposure of wood to high temperatures (212 C for 8 h) improved the thermal stability and crystallinity of wood. Heat treated pine and maple filled nylon 6 composites (at 20 wt.% loading) had higher tensile strengths among all formulations and increased tensile strength by 109% and 106% compared to neat nylon 6, respectively. Flexural modulus of elasticity (FMOE) of the neat nylon 6 was 2.34 GPa. The FMOE increased by 101% and 82% with the addition of 30 wt.% heat treated pine and 20 wt.% heat treated maple, where it reached maximum values of 4.71 GPa and 4.27 GPa, respectively. The rheological properties of the composites correlated with the crystallinity of wood fillers after the heat treatment. Wood fillers with high crystallinity after heat treatment contributed to a higher storage modulus, complex viscosity
and steady shear viscosity and low loss factor in the composites. This result suggests that heat treatment substantially affects the mechanical and rheological properties of wood filled nylon 6 composites. The mechanical properties and thermogravimetric analysis indicated that the heat treated wood did not show significant thermal degradation under 250 �C, suggesting that the wood-filled nylon composites could be especially relevant in thermally challenging areas such as the manufacture of under-the-hood automobile components.

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Anatomy of Wooden Core of Ottoman Composite Archery Bows

by Gokhan Gunduz and Seray Özden

Composite archery bows have been well known and used by Asiatic societies for thousands of years.... more Composite archery bows have been well known and used by Asiatic societies for thousands of years. The Turkish composite bow, made of wood, horn, sinew and glue is one of the most famous and powerful bows in the world. Because of its high draw weight and mechanical efficiency, the Turkish composite bow became a powerful weapon in the Seljuk and the Ottoman empire. In addition to being a powerful weapon of war, at the same time the bow and arrow (archery) continued to be a sport of Ottoman (sultans, state officials, janissaries) until the late Ottoman period. In this study of the Ottoman composite archery bows in the collections of Izmir Ethnography Museum, a small wood sample was investigated on the basis of its wood anatomy. The results showed that it was made of maple wood (Acer sp.) and some of its qualitative and quantitative anatomical properties are presented here. One of the key properties for the identification of maple wood is the helical thickening throughout the body of the vessel element. Helical thickenings in vessel elements in cutting surfaces of maple-wooden core increase the bonding surface between the wood and sinew-horn. In most of the woods preferred traditionally for bow-making, helical thickenings in tracheids, vessel elements or ground tissue fibres should be taken into account at a hierarchy of cellular structures for elucidating the efficiency of Ottoman composite-wooden bow.

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Effective Microorganisms (EM) Technology in Plants

Effective microorganism technology has been used in the fields of agriculture and forestry recent... more Effective microorganism technology has been used in the fields of agriculture and forestry recently. This technology is totally natural and environmentally friendly. BAIKAL EM1, a product of this technology, includes the photosynthetic lactic acid bacteria, ferments and products that are formed by the metabolism activities of these ferments and bacteria (enzymes, vitamins etc.) This microbiological fertilizer has a positive effect in growing plants; to their development and metabolism.

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Optimization of the Conditions Required for Chemical and Biological Modification of the Yeast Waste from Beer Manufacturing to Produce Adhesieve Compositions

During the production of beer large amounts of yeast waste are generated. This paper considers th... more During the production of beer large amounts of yeast waste are generated. This paper considers the possible making of environmentally friendly adhesive compositions from such wastes. Chemical treatment of yeast wastes increases their adhesive characteristics. Chemical crosslinking with glutaric aldehyde and biological cross-linking by enzyme transglutaminase improves the moisture resistance of the adhesive compositions. In terms of their physical and mechanical parameters they are not inferior to glues of natural origin and can be used for bonding paper, cardboard, and wood. The bonding strength of paper was 421.8 N / m, and that of wood was 27.8 MPa.

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The influence of mass loss on mechanical properties of heat treated black pine wood

by Gokhan Gunduz and Deniz Aydemir

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Wood pellets—tomorrow’s fuel for europe

by Gokhan Gunduz and Nedim Saracoğlu

Wood pellets are an economic, sustainable, and environmentally friendly alternative to the fossil... more Wood pellets are an economic, sustainable, and environmentally friendly alternative to the fossil fuels available. Both new and residual wood is used to supply the pellet production, and new raw material resources are constantly being developed. As well as residual wood, scrap wood such as tree tops and thinner trunks are readily used in pellet production. In the near future, the growing of energy-rich woods on fallow agricultural areas could provide even more resources for pellet production in many countries.

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The effect of mass loss on mechanic properties of heat treated paulownia (paulownia elongata) wood.

by Gokhan Gunduz and Deniz Aydemir

The effect of treatment time on dimensionally stability, moisture content and mechanical properties of heat treated anatolian chestnut (castanea sativa mill.) wood

by Alper Aytekin, Gokhan Gunduz, Bulent Kaygın, and Deniz Aydemir

Changes in specific gravity and equilibrium moisture content in heat-treated fir (abies nordmanniana subsp. bornmulleriana mattf.) wood

by Gokhan Gunduz and Deniz Aydemir

The goal of this study was to determine the changes in specific gravity and equilibrium moisture ... more The goal of this study was to determine the changes in specific gravity and equilibrium moisture content of fir (Abies nordmanniana subsp. bornmulleriana Mattf.) wood after heat treatment at different temperatures and durations. In this study, the effects of three different temperatures and three different durations were investigated. The temperatures were 170, 190, and 210°C, and the durations were 4, 8, and 12 h. The equilibrium moisture contents of the heat-treated specimens were determined at 20°C at relative humidities of 35, 50, 65, 80, and 90%, and the results were compared with control specimens. The results indicated that increasing temperatures increased the weight loss of the specimens. With respect to dimensional stabilization, the heat-treated specimens had lower equilibrium moisture contents than did the control specimens.

The influence of thermal treatment on color responses of wood materials

by Gokhan Gunduz, Deniz Aydemir, and Seray Özden

In this study, the influence of thermal treatment on color changes of six different wood material... more In this study, the influence of thermal treatment on color changes of six different wood materials was investigated. Test specimens were subjected to three different temperatures (160, 180, and 200°C) and durations (3, 5, and 7 h). The data obtained were analyzed using variance analysis, and then the statistical analysis of Tukey's test was conducted. After this treatment, the results showed that the color values of the six wood materials changed significantly. It was determined that L* (lightness) values decreased; the minimum change in L* was ∼4% for Juniper wood, and the maximum change in L* was ∼64% for Beech wood. The values of a* (red coordinate) and b* (yellow coordinate) showed varying levels of increase when the heat treatment conditions were 160°C for 3 to 7 h (not including Cherry wood), but the values began to decrease slowly after treatment at 160°C for 5 h. The ratios of the minimum and maximum color change in a* and b* were determined at 180°C for 3 h in Plane wood, 200°C for 5 h in Hazelnut wood, and 160°C for 3 h and 200°C for 7 h in Beech wood. As temperature and duration were increased, the minimum total color change (ΔE) was ∼3.5% for 160°C at 3 h in Cypress wood, and the maximum total color change (ΔE) was ∼50% for 200°C at 7 h in Cypress wood.

Turkish wooden arrow construction

Bow and arrow are the most ancient weaponry of the mankind in history and there are evidences tha... more Bow and arrow are the most ancient weaponry of the mankind in history and there are evidences that they have existed all over the globe since prehistoric times. Turkic people have used many species of trees for arrow construction. Most widely used tree species are Scots Pine (Pinus sylvestris L.), Ida Mountain Fir (Abies equitrojani Aschers. et Sint.) and Oriental Beech (Fagus oriantalis Lipsky.). If it would not result in strength loss,
species with low density wood is preferred to obtain lightweight structures in arrow shafts. High elasticity module supports increase of bending strength for arrow shaft which is already slender and fragile. Arrow lengths tend to vary between 60 cm and 80 cm while arrow masses range between 9 gr and 50 gr arrows could be classified by material but it would not be accurate because each part of arrow consisted by different material. As arrows shafts may be sorted as wooden and bamboo, arrow classes can be sorted as war, field, target, flight, and practice and contest arrows. Ottomans named arrow sections anthropologically. Arrow shaft is divided into 24
equal sections. First 4 sections from nock towards point named as head, the section where head ends is called neck, the 11. section is called belly, sections between neck and belly are called chest, sections between belly and 17. section are called calf, sections between calf and point are called foot. Turkish archers have great records in flight shooting. There is a record that measures 845.5 m and still is not beaten with similar equipment.
Keywords: Arrow, Bow, Wood, Turkish Arrow Construction.

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