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Öğe Analysis of Postural Load During Tasks in Some Machines Related to Panel Furniture Production By Using The OVAKO Working Posture Analyzing System (OWAS)(Kastamonu Univ, Orman Fak, 2012) Ulker, Onur; Burdurlu, ErolIn this study, it was aimed to classify and analyze the posture of body members of workers working at the machines of circular saw, edge banding and vertical boring at the partial process of panel furniture manufacturing according to the loads and strains. Research was realized at a small-scale firm in Ankara. OWAS (Ovako Working Postures Analyzing System) method was used in classifying of working postures. In accordance with the method, processes were taken video cam in 30 seconds and postures of the body members of workers were classified according to the danger. It was made modifications in the processes that higher loadings and strains taken place and new processes were taken video cam again for classification and analyzing. The arrangements that were made provided a reduction 37 % in the values of danger class.Öğe The Effect of Densification Temperature on Some Physical and Mechanical Properties of Scots Pine (Pinus sylvestris L.)(North Carolina State Univ Dept Wood & Paper Sci, 2012) Ulker, Onur; Imirzi, Ozgur; Burdurlu, ErolAs wood's density increases, strength properties tend to increase due to a decrease in cavity volume. This study aimed to determine the effect of temperature levels in the densification process with an open-system thermomechanical method on the density, bending, modulus of elasticity in bending, compression, shear strength, and Brinell hardness in radial/tangential directions of Scots pine. The densification process significantly increased the strength properties of Scots pine. This increase stemmed from the decrease in the rate of cavities with the densification process, which also resulted in an increase in cell wall elements that have load-bearing properties per unit volume. An increase in densification temperature decreased strength properties. The decrease in the strength values can be explained by increasing chemical degradation with a rise in the temperature level. The most suitable temperature level was 120 degrees C for a higher bending, shear, and compression strength, and it was 140 degrees C for a higher radial and tangential hardness in the densification of Scots pine. Increases of 42% in the bending strength, 20% in the shear strength, 47% in the compression strength, 242% in the radial hardness, and 268% in the tangential hardness were obtained after densification.Öğe Effect of Glass Wool and Stone Wool Additives on Some Mechanical Properties of Wood Composites(North Carolina State Univ Dept Wood & Paper Sci, 2016) Ulker, Onur; Burdurlu, ErolMechanical properties of wood composites made from multiple wood species (50% Crimean pine, 30% Eastern Black Sea oak, 15% quaking aspen, and 5% wood machining residues) were evaluated using various amount of glass wool (GW) and stone wool (SW) additives. A total of 70 experimental panels were produced with a target density of 640 kg/m(3). The bending strength, modulus of elasticity, tensile strength parallel to the surface of boards, tensile strength perpendicular to the surface of boards (internal bond), and cutting (shear) strength parallel to the surface of boards were determined. After statistical analysis, the results indicated that the SW and GW additives decreased the bending strength and modulus of elasticity by 49% in almost all boards. The addition of SW resulted in a 6% reduction in the tensile strength parallel to the surface. Relative to SW, GW resulted in an additional 8% reduction in shear strength, a 3% reduction in the screw tensile strength perpendicular to the surface, and a 6% reduction in the tensile strength parallel to the surface. Thus, the SW and GW additives decreased all the selected mechanical properties of wood composites.Öğe Effects of Some Mineral Wools and Adhesives on Burning Characteristics of Particleboard(North Carolina State Univ Dept Wood & Paper Sci, 2015) Ulker, Onur; Burdurlu, ErolIn this study, effects of adhesive and additive's type and ratio on burning characteristics of particleboard (PB) added glass wool (GW) and rock wool (RW) were researched. PB's furnish was derived from 50% Crimean pine, 30% Eastern Black Sea oak, 15% quaking aspen, and 5% residues of wood machining, and moisture content of furnish was 1.5 to 3%. Seventy PBs with 0.64 g/cm(3) density, urea formaldehyde (UF)/melamine formaldehyde (MF) fixed amount, 14 mm thickness, 45x45 cm(2) dimensions and 10%, 15%, 20% SW/GW additives were produced. The 150 degrees C pressing temperature with 25 kg/cm(2) compression pressure was constant. Burning tests for determination of ignition time, flaming combustion temperature, flaming combustion duration, smoldering combustion duration, and mass loss during burning were made according to DIN4102 standards. According to the results of the tests, adhesive type did not affect ignition time and mass loss. While flaming combustion temperature of PB with UF was 19% higher, flaming combustion duration and smoldering combustion duration was 32% and 29% lower than those of PB with MF, respectively. While ignition time of PB with GW was 50% higher than that of PB with RW, changes in burning properties were similar for both PBs. An increase in the content of GW and RW affected burning properties of PB positively and an increase of ignition time up to 196% were obtained.Öğe Evaluation Of Corner Joint Strength Of Composite Panels Bonded With Modified Starch(SLOVAK FOREST PRODUCTS RESEARCH INST, 2020) Ulker, Onur; Derafs, Mercan HaddadThe objective of this research was to evaluate the strength of corner joints of box shaped furniture made from eastern red cedar (Juniperus virginiana L.) and corn starch binder southern sample. Various types of corner joint techniques were evaluated (glued, glued and screwed, and glued with dowel corners). Eastern redcedar particle samples with corn starch and glutaraldehyde were used. Overlaid and non-overlaid particleboards along with sandwich panels were used at "L" type corner joints. Tension and compression strength moment values were measured. Particleboard panel joint mounted with dowel resulted in the highest tension strength moment values followed by the specimens having a sandwich-type configuration combined with a dowel. Particleboard and overlaid sandwich-type panels glued with polyvinyl acetate (PVAc) had the lowest strength values. It appears that composite panels manufactured with modified starch have the potential to be used for corner joints.Öğe Mobilya İmalatı Esanasında Oluşan Gürültü Emisyonlarının ve Maruziyetinin Araştırılması(Kırıkkale Üniversitesi, 2018) Ulker, OnurMobilya imalatı, ülkemizdeki imalat sektörlerininiçinde önemli yere sahiptir. Mobilya imalatının büyük çoğunluğu küçük ve ortabüyüklükteki (KOBİ) işletmelerde yapılmaktadır. Bu işletmeler genelliklemobilya imalatını tekil makinalar, CNC ve NC makineler kullanarak yapmaktadır.Bu makinalarda çalışanların gürültüye maruz kaldıkları bilinmektedir. Ankara’dafaaliyet gösteren KOBİ’ler genellikle Siteler bölgesinde bulunmaktadır. Buçalışmada, Ankara Siteler’de faaliyet gösteren 1500 m2 büyüklüğündebir KOBİ’nin imalat sistemine bağlı gürültü analizi yapılmıştır. Atölyeiçindeki 21 noktada gürültü analizi yapılmış makinaların boş ve doludurumlarına göre maruziyet seviyeleri belirlenmiştir. Günlük 8 saatlik çalışmasürecinde 85 dB(A) değerinde ve üzerinde olan maruziyetler riskli maruziyetolarak ele alınmış, riskli maruziyet oluşturan makine ve iş istasyonlarıbelirlenmiş, çalışanlar bilgilendirilmiş ve maruziyet değerlerini azaltanalternatifler geliştirilmiştir.Öğe Properties of Thermally Treated Yellow Poplar, Southern Pine, and Eastern Redcedar(North Carolina State Univ Dept Wood & Paper Sci, 2018) Ulker, Onur; Aslanova, Fidan; Hiziroglu, SalimProperties were evaluated for heat-treated yellow poplar (Liriodendron tulipifera), eastern redcedar (Juniperus virginiana), and southern pine (Pinus echinata) samples. Differences in discoloration, surface roughness, and hardness of the samples as a function of heat exposure were tested at temperature levels of 130 degrees C, 160 degrees C, and 190 degrees C. The experiments were carried out on defect-free eastern redcedar, yellow poplar, and southern pine samples with dimensions of 50 cm by 4 cm by 2 cm (longitudinal, radial, tangential) supplied by a local sawmill. A total of 80 samples, 20 for each temperature level, were used for the tests. Based on the findings, it appears that eastern redcedar specimens had the least discoloration values as compared to those of two other types of wood. In all cases, hardness values of the samples showed adverse influence of heat exposure. It seems that as temperature level increased, the surface quality of the samples from all three species was enhanced. All types of samples had significant discoloration as a result of heat treatment, and such findings were more prominent in the case of both pine and yellow poplar specimens. Overall hardness characteristics of the samples were adversely influenced due to heat exposure.Öğe Some mechanical properties of densified and laminated Lombardy poplar (Populus nigra L.)(Slovak Forest Products Research Inst, 2016) Ulker, Onur; Burdurlu, ErolIn this study, it was studied the effects of densification and then lamination processes on some mechanical properties of Lombardy poplar (Populus nigra L.), which is one of the low density tree species. Densification temperatures were 80, 100, 120 and 140 degrees C and ratios of densification were 15, 30 and 50 %. Furthermore, lamellas with a thickness of 4 mm cut from densified materials were laminated by bonding one on top of the other with urea formaldehyde (UF) and polyvinyl acetate (PVAc) adhesives. Bending, modulus of elasticity, compression and tensile tests were applied by preparing specimens from the pieces. According to test results, the most suitable temperature level was 120 degrees C. As the ratio of densification was increased at this temperature level, increase were observed in the mechanical properties. Also, lamination provided significant increases in the mechanical values compared to laminated but undensified Lombardy poplar. Increases were observed in the mechanical properties reaching 444 % with application of densification and lamination processes.Öğe Some Properties of Densified Eastern Redcedar as Function of Heat and Pressure(Mdpi Ag, 2017) Ulker, Onur; Hiziroglu, SalimThe objective of this study was to evaluate some of the properties of densified eastern redcedar as function of temperature and pressure. Surface quality, adhesive bondline shear strength, hardness, and color changes of the samples compressed using different temperature levels ranging from 100 degrees C to 180 degrees C were investigated. Based on the findings in this work, surface roughness of compressed specimens decreased with increased temperature. Overall adhesive bondline shear strength of the samples decreased as compared to that of control specimens as a result of compression. It appears that densified samples exposed to a temperature of 180 degrees C had significantly darker surface than those of the others, based on color measurement. Data found in this work provide some basic information for more efficient use of underutilized species such as eastern redcedar.Öğe Surface Roughness of Composite Panels as a Quality Control Tool(Mdpi, 2018) Ulker, OnurThis paper describes a study of the quantify surface roughness of experimentally manufactured particleboards and sandwiched panels having fibers on the surface layers. Surface quality of specimens before and after being overlaid with thin melamine impregnated papers was determined by employing profilometer equipment. Roughness measurements and Janka hardness were carried out on the specimens conditioned at 60% and 95% relative humidity levels. Based on the findings in this work, surface roughness of the specimens that were exposed two relative humidity exposure showed significant differences from each others. Data determined in this study could be beneficial to understand behavior of such panels exposed different humidity levels.Öğe Toxicity of Formaldehyde, Polybrominated Diphenyl Ethers (PBDEs) and Phthalates in Engineered Wood Products (EWPs) from the Perspective of the Green Approach to Materials: A Review(North Carolina State Univ Dept Wood & Paper Sci, 2019) Ulker, Ozge Cemiloglu; Ulker, OnurAdhesives, flame-retardant chemicals, and paints are used in engineered wood products (EWPs) to increase some of the properties of wood. Most of the engineered wood composites, including plywood, particleboard, and fiberboard, used as furniture components contain formaldehyde resins as an adhesive. The International Agency for Research on Cancer (IARC) added formaldehyde to the list of human carcinogens (Group 1) in 2004. Flame-retardant chemicals are semi-volatile organic compounds that can migrate from the products to the air. There are developmental neurotoxic effects from flame-retardant additives, among which polybrominated diphenyl ethers (PBDEs) are commonly used in EWPs. The flexibility and durability of plastics are increased using phthalates, which are a class of synthetic chemicals, by adding them to the polyvinyl chloride (PVC) that is used in the wood-plastic composites (WPC). Formaldehyde, PBDEs, and phthalates are toxicants that are commonly present in value-added furniture products. This review summarized the toxic effects of these chemicals from the aspect of human health and from the perspective of green products.Öğe Wood Adhesives and Bonding Theory(Intech Europe, 2016) Ulker, OnurIn this last century, world had grown faster than before; now people need more furniture than in the past century. More furniture means, more particleboards and more adhesives. Wood adhesives are used in every step of furniture manufacturing. Wood adhesives aim to bond wooden materials with each other or with different materials. Today, production with a faster pace is more important. Furniture production lines could be more productive with fast curing glues. Wood adhesives are used in more than 70% of wood products today in the world. The main reason is their use in gluing furniture joints and wood composite materials. In this chapter, readers can find four different topics: (1) technical properties of wood adhesives, (2) environment friendly adhesives, (3) semisynthetic adhesives, and (4) synthetic adhesives.
