Browsing by Author "Kesik H.İ."

Now showing 1 - 5 of 5

Determining the Effects of Some Bacteria on Wooden Toys Treated with Antibacterial Protective Coatings
(2022-01-01) Aykan R.; Avşar C.; Bilgiç M.B.; Kesik H.İ.
Several protective coatings enhanced by antimicrobial agents and/or pigments were considered for the wooden toy market: water-based matte varnish, an ultra-hygiene water-based matte varnish (WBV-UH), a polyurethane matte varnish (PUV), and an ultra-hygiene antiviral polyurethane matte varnish (PUV-UH), as well as a water-based dye (WBV 5%K), an ultra-hygiene water-based dye (WBV-UH 5%K), a polyurethane dye (PUV 5%K), and an ultra-hygiene polyurethane dye (PUV-UH 5%K), which contain 5% red nano-pigment (K). By utilizing 7 kinds of bacteria and 2 types of yeast that are commonly detected in routine, daily settings, the efficacy of the different protective coatings on wooden toy surface was investigated. The antibacterial and antimicrobial activities of the tested dye samples were based on the agar-well diffusion method. Ultimately, the study found that the addition of antimicrobial agents to several different protective coatings and dyes resulted in the presence of antimicrobial activity vs. the lack thereof with protective coatings and dyes alone. Additionally, some of the dyes with added antimicrobial agents were found to be effective against biofilm formation. Overall, the addition of pigment into the coating, alongside the addition of antimicrobial agents, proved to be highly effective in inhibiting growth and spread of microorganisms on wooden toy surface.
Effect of Heat Treatment Parameters on the Physical, Mechanical, and Crystallinity Index Properties of Scots Pine and Beech Wood
(2022-01-01) Birinci E.; Karamanoglu M.; Kesik H.İ.; Kaymakci A.
Effects of heat treatment parameters on the physical properties, mechanical properties, and crystallinity index of Scots pine and beech wood were investigated. Scots pine (Pinus sylvestris L.) and beech (Fagus orientalis Lipsky) sapwood samples were prepared in 2 cm × 2 cm × 36 cm dimensions by considering the physical and mechanical tests. The samples were heat-treated for 2 h and 4 h at 150 °C, 180 °C, and 210 °C in an atmospheric environment. The shrinking and swelling percentages of all samples were calculated. The compressive strength, bending strength, modulus of elasticity (MOE), and hardness tests were carried out. X-ray diffraction (XRD) was performed to calculate the crystallinity index values. As a result of the study, it was determined that heat treatment generally had a positive effect on the physical properties of Scots pine and beech samples. It was observed that the bending strength of the wood samples decreased up to 180 °C as the temperature increased and then increased. It was determined that the MOE of the Scots pine and beech wood decreased with the heat treatment. As the heat treatment temperature and time were increased, the crystallinity index values initially increased partially and then decreased.
Effect of Treatment Temperature on the Initial Performance of Layers of Water-based Paints in Heat-treated Pine and Beech Wood
(2022-01-01) Karamanoğlu M.; Birinci E.; Kesik H.İ.; Kaymakcı A.
Hardness, surface roughness, and adhesion strength were determined for water-based opaque paints applied to heat-treated wood material surfaces. For this purpose, Scotch pine (Pinus sylvestris L.) and beech (Fagus orientalis Lipsky) woods were used as experimental material. Specimens were subjected to heat treatment at 3 different temperatures (150, 180, and 210 °C) and 2 different periods (2 and 4 h) under laboratory conditions. Two-component water-based paints with commercial codes D17 and D45 were applied to the surfaces. The hardness, surface roughness, and adhesion strength values of painted samples were determined according to the applicable standards. The results showed that there were higher values of hardness and surface roughness of water-based paints in short-term heat treatment compared with long-term heat treatment. A general decrease in pine with D17 and D45 paints applied to the surfaces and in beech with D45 in adhesion strength was detected depending on the increasing heat treatment temperature and duration. An increase was observed in beech samples with D17 paint applied.
Experimental and numerical analysis of compression and bending strength of old wood reinforced with CFRP strips
(2021-10-01) Karagöz Işleyen Ü.; Kesik H.İ.
The reinforcement and repair of historical wooden structures is very important because they reflect the socio-economic structure and architectural construction techniques of the period it was built. In this study, carbon fiber-reinforced polymer (CFRP) strips were used to improve the mechanical behaviors of old wood (OW) samples that were damaged over time because of various environmental effects and biological factors. To determine the effect of reinforcement on the strength values of OW and new wood (NW) samples under bending and compression loads, CFRP strips were applied at tension surfaces of bending samples and around the perimeter of compression samples. The effect of reinforcement on mechanical properties of OW and NW samples was evaluated with a statistical analysis program. Moreover, the ductility and energy dissipation capacities of experimental samples was calculated from the load-deflection curve obtained under bending loading. Reinforcement with CFRP has significantly improved the mechanical strength and stiffness of OW samples. The bending strength values increased 28%, 34% and 59% for new wood (NW), reinforced old wood (FROW) and reinforced new wood (FRNW) with respect to the non-reinforced OW, respectively. The modulus of elasticity values of NW, FROW and FRNW were 15%, 19% and 34% higher than OW, respectively. The 3-dimensional numerical model was developed and validated by experimental tests carried out on wood samples with and without reinforcement arrangements. Wood behaviors were modeled using uniaxial stress-strain curves. In numerical analysis, load-deflection curves, equivalent stresses and normal stresses of the beams were obtained. A good correlation was obtained between numerical and experimental results.
Factors affecting some properties on surface of thermowood material applied with water-based varnishes modifed with nanoparticles
(2021-01-01) Karamanoğlu M.; Kesik H.İ.
Background: The aim of this study is to determine the surface roughness and adhesion strength of water-based varnishes modified with nanoparticles of zinc oxide (ZnO) and hollow ceramic spherical (HCS) against accelerated UV aging effect in some ThermoWood materials. For this purpose, American ash (Fraxinus americana) and scotch pine (Pinus sylvestris Lipsky) wood were heat treated at a temperature of 190 °C for 1.5 hours and 212 °C for 2 hours. The heat-treated samples were applied with two-component water-based varnishes, with D70-D99 commercial codes, modified with 1%, 3% and 5% ZnO and HCS nanoparticles individually then these samples were subjected to accelerated aging for 240 hours according to ASTM G154. The surface roughness of varnish layers was determined by TS 6956 EN ISO 4287/A1 and surface adhesion strength by ASTM D4541 principles. Results: The results showed that the nanoparticles generally decreased the surface roughness and adhesion strength in water based varnishes. But surface roughness increased in additives of 5% HCS in D99 and 1% ZnO in D70. Also adhesion strength increased in additives of 5% ZnO and 1% and 5% HCS in D70. Conclusion: The layer properties of water-based varnishes can be improved with ZnO and HCS nanoparticles against aging effects.