Browsing by Author "Oral, İmran"

Now showing 1 - 4 of 4

Citation - WoS: 12
Citation - Scopus: 14
Characterization of Unmodified and Modified Apricot Kernel Shell/Epoxy Resin Biocomposites by Ultrasonic Wave Velocities
(Springer, 2022) Oral, İmran; Kocaman, Süheyla; Ahmetli, Gülnare
The main goal of this research was to develop highly durable, low-cost eco-friendly biocomposites from apricot kernel shell (AKS) wastes and ultrasonic characterization of AKS-based obtained biocomposites. Natural AKS wastes were chemically modified using 5 wt% sodium hydroxide (NaOH) and 99 wt% glacial acetic acid (AA). These modified apricot kernel shells (MAKS) and unmodified apricot kernel shells (UMAKS) were added into bisphenol-A type epoxy resin (ER) in varied compositions such as 10-50 wt% to prepare the MAKS/ER and the UMAKS/ER biocomposites. The epoxy resin-mixture in the weight ratios of resin/hardener/accelerator was 100:30:1. The effect of AKS powder ratios and modifiers on the elastic properties (Young's moduli [E], bulk moduli [K], longitudinal moduli [L], shear moduli [G], and Poisson's ratio [mu]), density (rho), damping properties (attenuation coefficient [alpha], loss tangent [tan delta], and quality factor [Q]), ultrasonic micro-hardness (H), and acoustic impedance (Z) of biocomposites was investigated by the ultrasonic testing (UT) method. The morphological structure of the ER and biocomposites was figured out using scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The results revealed an increase in elastic properties of most of the AKS/ER biocomposites compared to the neat ER. On the other hand, results have shown that SEM and XRD images' analysis confirmed the amorphous structure of ER and biocomposites. The highest rho, v(L), v(S), L, G, E, H, and Z values were obtained in MAKS-AA/ER-5 biocomposite. Thus, it can be stated that the MAKS-AA/ER-5 biocomposite sample has the best mechanical properties. Also, the results revealed that the MAKS-AA/ER-1 sample can be used as an alternative material for its high Q-factor value instead of wood in producing musical tools.
Citation - WoS: 5
Citation - Scopus: 5
Determination of Mechanical and Damping Properties of Hazelnut Shell Powder Reinforced Biocomposites by Ultrasonic Method
(Wiley, 2023) Oral, İmran; Kocaman, Süheyla; Cerit, Alaaddin; Ahmetli, Gülnare
This research was carried out to figure out the effect of chemical treatments of hazelnut shell powders (HSPs) on the elastic properties, ultrasonic wave velocities, and damping properties of bio-based epoxy resin (BER) biocomposites. Natural hazelnut shells (HSs) were chemically treated using sodium hydroxide (NaOH), and acetic anhydride (AA). Then, HSs that were chemically treated with NaOH and AA, and HSs that were not subjected to chemical treatment were ground to obtain HSPs. The treated HSPs (HSP-NaOH and HSP-AA), and untreated HSPs were contributed to the neat BER in varied compositions such as 10-50 wt% to obtain the BER/HSP, BER/HSP-NaOH, and BER/HSP-AA biocomposites. The effect of untreated, and treated HSP ratios on the density, ultrasonic wave velocities, Young's modulus, Bulk modulus, Shear modulus, Poisson ratio, microhardness, and damping characteristics (attenuation coefficient, loss tangent and quality factor) of the novel HSP-based biocomposites, was investigated by the ultrasonic pulse-echo overlap method (PEOM). A significant increase in the density, ultrasonic wave velocities, and elastic modulus values of the biocomposites was seen compared to the neat BER. Based on the obtained elastic modulus values, the most appropriate combination ratio between the neat BER, and HSP-NaOH was determined as 50:50.
Citation - WoS: 1
Citation - Scopus: 1
Investigation of the Effects of Gamma Radiation and Y2o3 on the Elastic Properties of Al2024 Composites by Ultrasonic Method
(PERGAMON-ELSEVIER SCIENCE LTD, 2025) Demir, Hikmettin; Ataş, Mehmet Şahin; Oral, İmran
In this study, the effect of Y2O3 contribution and gamma-irradiation on the elastic properties of pure Al2024 and Al2024/Y2O3 composites was precisely investigated with the help of determined density and ultrasonic wave velocities. Ultrasonic longitudinal and shear wave velocity measurements of the samples were performed at room temperature using the ultrasonic pulse-echo method at 20 and 5 MHz frequencies, respectively. X-ray diffraction analysis and scanning electron microscopy examined the microstructural properties and phase characterizations of metal matrix composite (MMC) samples. A gamma cell type Co-60 source was used to irradiate MMC samples in the air at room temperature. The absorbed dose rate was measured to be approximately 1.5 kGy/h, and the total delivered dose was 50 kGy. According to the findings obtained from the research, the contribution of Y2O3 to pure Al 2024 at 0.5, 1, and 5 wt% ratios and exposure to gamma rays of 50 kGy caused a decrease in V-L, L, K, and mu values and a significant increase in rho, V-S, G, HV, H, and E values. The highest Young's modulus values compared with pure Al2024 were obtained in both unirradiated and irradiated Al2024/0.5Y(2)O(3) composites.
Citation - WoS: 10
Citation - Scopus: 13
Preparation and Ultrasonic Characterization of Modified Epoxy Resin/Coconut Shell Powder Biocomposites
(WILEY, 2022) Oral, İmran; Kocaman, Süheyla; Ahmetli, Gülnare
A new bio-based epoxy resin (BER) is produced by the esterification reaction between sebacic acid (SAc) as bio-based acid and epichlorohydrin (ECH). The epoxy resin (ER) is modified with the BER. The biocomposites are prepared using untreated coconut shell powder (CSP), modified coconut shell powder (MCSP), and MER. The CSP and MCSP particles are mixed with MER in varied compositions (10-50 wt%) for preparation of the MER/CSP and MER/MCSP biocomposites. The influences of CSP and MCSP bio-fillers amounts on the physical properties (density, elastic constants, acoustic impedance, ultrasonic micro-hardness, and attenuation coefficient) of biocomposites are investigated using the ultrasonic pulse-echo overlap method (PEOM). It was seen that the densities, both ultrasonic longitudinal and shear waves' velocity values of obtained biocomposites were higher than those of the MER. All elastic moduli of the MER/MCSP biocomposites have higher values than of the neat MER and MER/CSP biocomposites.