https://hdl.handle.net/20.500.12809/181 2026-04-04T04:50:59Z https://hdl.handle.net/20.500.12809/11039 Strength Classification of Wooden Chairs under Cyclic Loads Based on an Experimental Study Diler, Harun; Kasal, Ali; Kuşkun, Tolga; Erdil, Yusuf Ziya; Güray, Ersan This study aimed to assess the cyclic load capacity of wooden chairs and subsequently categorize them based on their performance. A diverse selection of chair models was randomly procured from commercial markets. These chairs underwent performance testing, utilizing the cyclic stepped increasing loading method, with adherence to the standards set forth by the American Library Association Technology Reports (ALA). The study evaluated 315 chairs, encompassing 21 chair models. Each chair model underwent five replications of testing across three different loading directions. The resulting dataset of numerical values was subjected to statistical analyses, facilitating the categorization of chairs based on their strength under cyclic loads. Notably, the study revealed substantial variations in the load capacity among different chair models. As a consequence of this investigation, the study established acceptable design load thresholds. For instance, concerning front-to-back loading, it was determined that the chairs with cyclic load capacities ranging from 932 to 1449 N fell within the category of low-strength, between 1450 and 1968 N were classified as medium-strength (suitable for domestic use), and the chairs with cyclic load capacities exceeding 1968 N were considered to possess high strength (intended for hotel lobbies, restaurants, libraries, etc.). Similarly, for back-to-front loading performance, the study identified the chairs with cyclic load capacities between 625 and 895 N as low-strength, 896 and 1167 N as medium-strength, and the chairs with loads surpassing 1168 N as high-strength. The performance thresholds for side thrust loads were as follows: low-strength encompassed the cyclic load capacities ranging from 649 to 934 N, medium-strength spanned the cyclic load capacities between 935 and 1221 N, and high-strength entailed 1222 N and above. Notably, the classification devised in this study is closely aligned with the widely accepted and internationally recognized ALA specification. This strong consistency with global standards reinforces the reliability and applicability of the classification system developed in this research. In conclusion, this study enhances understanding of wooden chair strength performance and offers practical insights that lead to higher-quality products and improved consumer satisfaction. Its recommendations can potentially drive positive change within the industry and benefit manufacturers and consumers. 2023-01-01T00:00:00Z https://hdl.handle.net/20.500.12809/10944 The Use of Herbal Extracts in Lacquer Paint Coloring and Determination of Some Mechanical Resistance Properties on Wood-Based Surfaces Göktaş, Osman; Bozkaya, Yaşar Tahsin; Yeniocak, Mehmet The aim of this study was to determine the usability of selected natural dye extracts as environmentally friendly colorants that are used in painting of MDF based furniture and evaluate their resistance to scratch resistance, adhesion resistance, and surface hardness properties. In this study, the water-based lacquer coatings were prepared with natural dyes obtained from purple cabbage (Brassica oleracea), safflower (Carthamus tinctorius), Red beetroot (Beta vulgaris) and three synthetic paints that were black, blue and light blue as a comparison. Coated MDF test panels used for evaluation of performances of dyes to abiotic factors that are determined by mechanical tests such as scratch resistance, adhesion resistance, and surface hardness. As a result of the study, it has been observed that, except for scratch resistance, natural dyes perform as well as synthetic ones as alternative colorants in the lacquer coatings. Thus, natural and aesthetic raw materials that are environmentally friendly dyes can be used safely especially in children’s furniture and for wood-based products that are especially used indoors. 2023-01-01T00:00:00Z https://hdl.handle.net/20.500.12809/10903 Mechanical and thermal properties of polyvinyl acetate foams reinforced with biopolymers Özen, Ertan; Ergun, Mehmet Emin; Yıldırım, Nadir; Dalkılıç, Berk The study developed and designed polyvinyl acetate (PVAc) foams using advanced freeze-drying technology, which exhibited good heat-insulating ability, flame retardancy, and mechanical properties. Different combinations of bleach kraft pulp, water-soluble chitosan, and zinc borate were used to reinforce the foams. The foams exhibited desirable compression and flexural properties, with compression strength and compression modulus ranging from 0.01 MPa to 0.08 MPa and 0.05 MPa to 0.29 MPa, respectively, while flexural strength and flexural modulus ranged from 0.12 MPa to 5.37 MPa and 9.86 MPa to 260,85 MPa, respectively. The use of zinc borate as a reinforcement resulted in improved thermal properties and reduced mass loss at 600°C by 20.69%. Thermal conductivity tests indicated that the foams had low thermal conductivity values ranging from 0.037 W/mK to 0.074 W/mK. The foams with zinc borate (60 g/L) and high molecular weight water-soluble chitosan (70 g/L) reinforcement exhibited high limiting oxygen index (LOI) of 28.72%. Overall, the results suggest that the PVAc foams could serve as a promising sustainable alternative in thermal insulation and construction fields. 2023-01-01T00:00:00Z https://hdl.handle.net/20.500.12809/10835 Coloration of Lacquered Coatings for Furniture Production with Herbal Dyes and Determining Weathering Resistance Göktaş, Osman; Bozkaya, Yaşar Tahsin; Yeniocak, Mehmet The main goal of the study is to produce eco-friendly furniture dyes by using bio-colorants and to determine the color stability of these dyes in outdoor conditions. In this regard, dye extracts obtained from red beet (Beta vulgaris), safflower (Carthamus tinctorius L.), and purple cabbage (Brassica oleracea), as a bio-colorant source, were applied to MDF test panels by mixing with water-based synthetic lacquer coatings. Also, three different synthetic dyes were applied to MDF test panels in order to compare the results with eco-friendly natural dyes. Natural dyes were mixed with metal and natural mordants such as iron sulfate, aluminum sulfate and vinegar. Lacquer coated test panels, coated with natural and synthetic dyes, were exposed to outdoor conditions for 50 days in Denizli/Turkey in order to assess the change in color. As a result, the maximum color stability occurred in the test panels lacquer coated with synthetic black dye, while the minimum color stability occurred in the test panels lacquer coated with synthetic light blue dye. It was determined that the thickness of the color coating layer applied to test panels increases color stability. It was also observed that the color stability performance of natural dyes is as good as that of synthetic dyes. 2023-01-01T00:00:00Z