Merih Palandöken;Aysu Belen;Ozlem Tari;Peyman Mahouti;Tarlan Mahouti;Mehmet A. Belen; 《国际射频与微波计算机辅助工程杂志》2024,2024(1):5442768

In this paper, deep learning–based data-driven surrogate modeling approach is proposed for enhancing cost-efficiency of multiband antenna design optimization. The proposed surrogate model–assisted design approach has achieved a computational cost reduction of almost 40% compared to the conventional direct electromagnetic solver–based design methodologies in case of single design example. As for the validation of the proposed method, the obtained optimal design parameters from the surrogate model are used to manufacture an antenna design. The obtained results from the experimental measurement are compared with counterpart results from the literature.  相似文献   

    

Sefa Durmaz  Ozlem Ozgenc Keles  Ugur Aras  Yusuf Ziya Erdil  Fatih Mengeloglu 《Coloration Technology》2023,139(4):430-440

In recent years, wood-plastic composites (WPCs) have become among the most popular engineering materials. Most of their usage areas are outdoors, where they encounter various damaging factors. The weathering conditions cause significant deterioration to WPC surfaces, which negatively influences their service life. In this study, zinc oxide nanoparticles at different concentrations (1%, 3%, 5%, 10%) were added to a high-density polyethylene-based WPC matrix. The effect of zinc oxide nanoparticles on the weathering performance of WPC was evaluated after 840 hours of an artificial weathering test. The highest colour changes (∆E*) were monitored with control samples exposed for 840 hours. Adding zinc oxide nanoparticles improved the ultraviolet (UV) resistance and decreased the colour changes. The wood flour content also affected the colour changes on the WPC surface. A combination of 10% zinc oxide nanoparticles and 50% wood flour content provided the lowest colour changes. The barrier effect of nanoparticles protected the WPC surfaces from UV light. Zinc oxide nanoparticles also positively affected the load transfer, which restricted the reduction in mechanical properties after the weathering test. The degradation on the surface of WPCs was also investigated using attenuated total reflectance-Fourier Transform–infrared analysis. The changes in the characteristic bands of polymer and wood indicated that surface degradation was inevitable. Light and scanning electron microscopy images also demonstrated micro-cracks and roughness on the surface of WPCs. It is concluded that UV degradation is unavoidable, but zinc oxide nanoparticles can improve surface resistance against weathering conditions.  相似文献   

    

Özge Şendil  Sema Samatya Yilmaz  Eda Yazici Ozcelik  Hüseyin Uzuner  Ayse Aytac 《乙烯基与添加剂工艺杂志》2023,29(1):48-65

In this study, the polyvinyl alcohol (PVA) and sodium caseinate (SC) nanofibers were produced by a single-fluid electrospinning method from their blends. Afterward, the cross-linking process with two different methods was applied to the PVA/SC (70/30, v/v) ratio, which was selected according to the surface and mechanical properties of the electrospun mat. In the first method, different ratios (15%, 20%, 25%, and 30%) of glutaraldehyde (GLA) cross-linking agents were added to the PVA/SC solution and then, PVA/SC/GLA nanofibers were obtained. In the second method (in-situ method), the nanofibers obtained from the PVA/SC solution were cross-linked by dipping into the cross-linking solution. After, PVA/SC/GLA/Zinc oxide nanoparticles (ZnO NP) mats were obtained by adding ZnO NP at different rates to the PVA/SC/GLA (7030-25GLA) solution, which was chosen according to the results of thermal, mechanical, and moisture test. In addition, performing tests, a cytotoxicity test for fibroblast cell line (L929), and in vitro antibacterial test for Escherichia coli and Staphylococcus aureus were also applied to them. Therefore, the usability of PVA/SC/GLA/ZnO NP nanofibers as an antibacterial effective wound dressing was investigated. Due to the high toxic effect of GLA, it was found that PVA/SC/ZnO cross-linked nanofibers are not suitable for wound dressing use. However, it was determined that the PVA/SC nanofiber cross-linked by the in-situ method had high cell viability according to the cytotoxicity test result and thus could be used as a fibroblast tissue scaffold.  相似文献   

    

Ozlem Ozgun  Raj Mittra  Mustafa Kuzuoglu 《International Journal of Numerical Modelling》2020,33(2):e2681

This paper presents a novel computational electromagnetics (CEM) technique, which hybridizes the periodic finite element method (FEM) with the method of moments (MoM), for efficient numerical modeling of electromagnetic scattering from metasurfaces consisting of truncated periodic or locally varying quasi-periodic array of structures. Based on the quasi-periodic nature of metasurfaces, the periodic FEM is employed to generate high-level macro basis functions (MBFs). Following that, a reduced MoM matrix is formed by using the MBFs with unknown coefficients belonging to each cell of the periodic array. The proposed hybrid method reduces the computational load significantly when compared with conventional numerical methods, especially for electrically large truncated metasurfaces involving arbitrarily inhomogeneous unit cells. Various numerical results are presented, and the accuracy and performance of the proposed method are tested against commercial codes, as well as an in-house FEM code.  相似文献