Ertürk, Ömer; Can, Zehra; Yaman, Mustafa

This work was accomplished to establish the chemical components and bioactivity potential of the nest materials of Polistes nimpha (Christ), Polistes dominula (Christ), and Vespa crabro (L.). The biological and chemical compounds of materials and their molecular functionalities were detected using FRAP (ferric reducing antioxidant power) method, DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free radical method, and Energy Dispersive X-Ray Analysis. Finally, the bioactivity potentials of nest extracts were assayed and phenolic components were determined. C, N, O, Na, Ca, K, Mg, Al, Si are the elemental components of the nest materials. All nest extracts of three species had high biological activity against nine bacteria and one fungus causing common infections. The maximum antibacterial and antifungal activity was seen when gram-negative Pseudomonas aeruginosa, gram-positive Bacillus cereus, and gram-positive Candida albicans were exposed to ethanol extracts of nest samples in 25 μL. High antioxidant activity can be found in the nest extracts. These extracts might help researchers find novel antifungal and antibacterial substances.

İncele

Maraş, Sinan; Yaman, Mustafa; Sansveren, Mehmet Fatih; Reyhan, Sina Karimpour

In recent years, studies on the development of new and advanced composite materials have been increasing. Among these new technological products, Fiber Metal Laminates (FML), and hybrid structures made of aluminium, carbon, glass or aramid fiber, are preferred especially in the aircraft industry due to their high performance. Therefore, free vibration analysis is necessary for the design process of such structures. In this study, the vibration characteristics of FML for clamped-free boundary conditions were investigated experimentally and numerically. Firstly, numerical results were obtained using Finite Element Method (FEM) and then these results were compared with the experimental results. It was seen that the numerical results were in good agreement with the experimental results. As the theoretical model was justified, the effects of various parameters such as number of layers, fiber orientations, and aluminium layer thickness on the in-plane vibration characteristics of the FML straight beam were analysed using FEM. Thus, most important parameters affecting the vibration characteristics of the hybrid structures were determined.

AtıfScopus21·WoS18·OpenAlex17

İncele