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- MakaleYalnız künye2026Synthesis, characterization, and thermal-magnetic evaluation of novel triazine-derived polyamides and their metal complexes
Çanakçı, Dilek; Sarıbıyık, Oğuz Yunus
In this work, novel triazine-containing polyamide derivatives possessing thermal stability and magnetic properties were synthesized. The synthesis process involves two steps: first, the chlorination of adipic acid and succinic acid using thionyl chloride; and second, the amidation of triazine. As a result of these procedures, two different triazine-containing polyamides were synthesized. The synthesized polyamides formed complexes with Ag, Cu, and Zn ions to enhance their thermal stability and magnetic properties.The structures of the synthesized polyamides were elucidated primarily by FTIR analysis, focusing on distinctive bands corresponding to the carbonyl group. The molecular structures of the polyamides were confirmed using 1H NMR and 13C NMR spectroscopy. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX) was employed to obtain information on the morphology and elemental composition of the samples. In addition, X-ray diffraction (XRD) analysis was performed to characterize the crystal structures, unit cell parameters, and orientations of the solid-state metal complexes. The thermal stability of both the polyamides and their metal complexes was investigated using thermogravimetric analysis (TGA). The magnetization of the synthesized compounds was measured as a function of temperature under zero-field-cooled (ZFC) and field-cooled (FC) conditions using a physical property measurement system (PPMS).
- MakaleAçık Erişim2024Characterization of cellulose produced by bacteria isolated from different vinegars
Güzel, Melih
Traditional vinegars are naturally produced from sugar- or starch-containing raw materials, through alcoholic fermentation followed by acetic fermentation. Fermentation is a spontaneous and complex process involving interactions between various microorganisms. In this study, we produced vinegar using traditional methods from six fruits: rosehip, pear, fig, wild pear, apple, and plum. Bacteria that produce bacterial cellulose (BC) were isolated from these vinegars and identified. In addition, we investigated the properties of BC produced from these bacteria. The strains isolated from vinegars were identified as Gluconobacter oxydans strain MG2022, Acetobacter tropicalis strain MG2022, Acetobacter fabarum strain MG2022, Komagataeibacter saccharivorans strain MG2022, K. saccharivorans strain EG2022, and Acetobacter lovaniensis strain OD2022. In total, 0.83–2.04 g/L BC was produced and the bacterial strain isolated from pear vinegar yielded the most BC. BC produced by the bacterial strain isolated from wild pear vinegar had the highest thermal stability and crystallinity (87.44 %). Overall, this study shows that different fruits contain different BC-producing bacteria in their natural flora and vinegars obtained from fruits can be used in BC production. Also, different BC-producing bacteria can be isolated from different vinegars, and BC produced by these bacteria might have different properties.
- MakaleYalnız künye2024Three novel 1,2,3-triazole-fused compounds: Syntheses, structural and spectroscopic characterizations with molecular modeling
Ejder, Esengül; Onur, Sultan; Yıldırım, Arzu Özek; Yıldırım, Muhammet Hakkı; Tümer, Ferhan
In this study, we report syntheses, structural and spectroscopic characterizations, and molecular modeling of three novel triazole fused compounds: 4-((4-methoxyphenoxy)methyl)-1-(4-methoxyphenyl)-1H-1,2,3-triazole, 1-(4-isopropylphenyl)-4-((4-methoxyphenoxy)methyl)-1H-1,2,3-triazole, and 1-(4-fluorophenyl)-4-((4-methoxyphenoxy)methyl)-1H-1,2,3-triazole. Their molecular structures and intermolecular interactions were elucidated using single-crystal X-ray crystallography. The compounds crystallize in the P-1 and P21/c space groups with weak C−H∙∙∙N and C-H∙∙∙O interactions. Hirshfeld surface analyses revealed the complex network of intermolecular interactions, determining that in all three compounds, an average of 13 % of the packing interactions were due to hydrogen bonds, and an average of 25 % were due to C-H···π interactions. Since the compounds differ from each other by only one substituent (methoxy, isopropyl, and fluorine) in their phenyl ring, their experimental infrared spectra were clarified by comparing them with the calculated ones. NMR spectroscopy was employed to examine the behavior of the compounds in solution. Conformational scans revealed that the energy differences between conformers are low, indicating potential conformations in which compounds could exist in solution. Nonlinear optical properties were calculated to evaluate the potential of the compounds for optical applications, particularly emphasizing the significantly larger values seen for two compounds compared to a reference compound. Finally, molecular electrostatic potential maps were generated to visualize the charge distribution and potential electrophilic and nucleophilic attack regions.
- MakaleAçık Erişim2015Preparation and characterization of electroless Ni-B/nano-SiO2, Al2O3, TiO2 and CuO composite coatings
Ekmekci, Dursun; Bülbül, Ferhat
Ni-B/SiO2, Al2O3, TiO2 and CuO composite coatings were successfully obtained by the electroless plating technique. Dispersible SiO2, Al2O3, TiO2 and CuO nanoparticles were co-deposited with electroless Ni-B coating onto AISI-304 steel substrates. Deposits were characterized for its structural properties by X-ray diffraction (XRD). XRD results showed a broad peak of Ni-B and low intensity composite nanoparticle peaks. The surface and cross-section morphology of samples were analysed using a scanning electron microscope (SEM). Surface analysis showed that the incorporation in Ni-B matrix of nano-SiO2, Al2O3, TiO2 and CuO particles increases the nodularity of composite coatings. The deposits are composed of a columnar structure grown along the vertical direction of the substrate surface. The results also show that electroless nanocomposite coatings tend to have greater microhardness compared with the coating without nanoparticles. The increase in the microhardness of the nanocomposite coatings reported in this study is attributed to an effect of dispersion strengthening of ceramic particles in the Ni-B matrix.
- MakaleYalnız künye2014EFFECT OF HEAT TREATMENT ON STRUCTURE OF ELECTROLESS Ni-B COATED PURE TITANIUM
Bülbül, Ferhat; Çelik, Ilhan
Pure titanium has a very large potential for use industrially due to its low weight, however, its usage continues to be limited because it possesses some disadvantages such as low hardness and wear resistance, weak corrosion resistance in high temperatures and high cost. In order to strengthen these weaknesses of pure titanium, electroless Ni-B deposition process, may be an alternative solution. In this study, the Ni-B coatings were deposited on pure titanium and annealed at the temperatures of 450 degrees C, 650 degrees C and 850 degrees C. The non-heat treated and heat treated coatings were structurally characterized via SEM (scanning electron microscope) and XRD (x ray diffraction). These coatings transformed from amorphous structure to a pronounced crystalline structure depending on heat treatment.
- MakaleYalnız künye2011Assessment of natural radioactivity and mass attenuation coefficients of brick and roofing tile used in Turkey
Damla, N.; Cevik, U.; Kobya, A. I.; Celik, A.; Celik, N.; Yildirim, I.
In this study the distribution of natural radionuclides ((226)Ra, (232)Th, (40)K) in brick and roofing tile samples commonly used as building materials in Turkey was measured by using gamma spectrometry. The activity concentrations, radium equivalent activities (Ra(eq)), representative level index, indoor absorbed dose rate in air values and annual effective dose due to the intake of the above-mentioned radionuclides in the brick and roofing tile samples were estimated to assess the radiation hazard for people living in dwellings made of the materials studied. The measured average activity concentrations of (226)Ra, (232)Th and (40)K were 34 +/- 14, 34 +/- 13 and 462 +/- 175 Bq.kg(-1), respectively, for brick samples. For roofing tile, the average activity concentrations of (226)Ra, (232)Th and (40)K were measured to be 34 +/- 14, 33 +/- 12 and 429 +/- 161 Bq.kg(-1), respectively. The concentrations for these natural radionuclides were compared with the reported data of other countries. The Ra(eq) values of all samples were lower than the limit of 370 Bq.kg(-1), equivalent to a gamma dose of 1.5 mSv.a(-1) recommended by OECD. This study shows that the measured brick and roofing tile samples do not pose any significant source of radiation hazard and are safe to be used as building materials. Moreover, the experimental mass attenuation coefficients (mu/rho) of brick and roofing tile samples were determined in the energy range 80-1332 keV using the gamma ray transmission method. The experimental mass attenuation coefficients were compared with theoretical values obtained using XCOM. It was found that the computed values and the experimental results of this work are in good agreement with those reported in the literature. The chemical compositions and structural analysis (XRD) of the brick and roofing tile samples are also presented. (C) 2011 Elsevier Ltd. All rights reserved.