Yazar "Bulut, Fatih" seçeneğine göre listele

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    A comparative study of 3D printing and sol-gel polymer production techniques: A case study on usage of ABS polymer for radiation shielding
    (Korean Nuclear Soc, 2024) Ogul, Hasan; Gultekin, Batuhan; Bulut, Fatih; Us, Hakan
    This study focuses on the comparative analysis of ABS polymer samples produced using two distinct manufacturing techniques: 3D printing and the sol -gel methods. In the first approach, ABS polymer was augmented with rare earth oxides, Er 2 O 3 and Gd 2 O 3 , in nano powder form and fabricated into test specimens using 3D printing technology. In the second approach, identical samples were prepared via the sol -gel technique involving mold-based fabrication. Elemental content analysis revealed no significant differences between the samples produced by the two methods. The study proceeds to evaluate the gamma-ray shielding, neutron shielding, temperature resistance, and SEM/EDS pictures of ABS samples generated through both techniques. 3D printing method exhibited more favorable results in terms of structure morphology and thermal stability while there is no significant difference for radiation shielding. The results provide insights into the performance and suitability of each production method for radiation shielding applications. This research not only contributes to enhancing radiation shielding technology but also informs the selection of the most appropriate fabrication method for specific applications in nuclear technologies and diagnostic energy range in medical purposes.
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    Advanced NH3 Detection by 1D Nanostructured La:ZnO Sensors with Novel Intrinsic p-n Shifting and Ultrahigh Baseline Stability
    (Amer Chemical Soc, 2024) Ajjaq, Ahmad; Bulut, Fatih; Ozturk, Ozgur; Acar, Selim
    Due to its stability, transportability, and ability to be produced using renewable energy sources, NH3 has become an attractive option for hydrogen production and storage. Detecting NH3 is then essential, being a toxic and flammable gas that can pose dangers if not properly monitored. ZnO chemiresistive sensors have shown great potential in real NH3 monitoring applications; yet, research and development in this area are ongoing due to reported limitations, like baseline instabilities and sensitivity to environmental factors, including temperature, humidity, and interferent gases. Herein, we suggest an approach to obtain sensors with competitive performance based on ZnO semiconducting metal oxides. For this purpose, one-dimensional nanostructured pure and La-doped ZnO films were synthesized hydrothermally. Incorporating large rare earth ions, like La, into the bulk lattice of ZnO is challenging and can lead to surface defects that are influential in gas-sensing reactions. The sensors experienced a temperature-induced p-n shifting at about 100 degrees C, verified by the Hall effect and AC impedance measurements. The doped sensor showed exceptional stepwise baseline stability and outstanding performance at a relatively low operating temperature (150 degrees C) with a sensing response of 91 at best (@ 50 ppm NH3) and recorded a tolerance to water vapor up to 70% RH. Alongside p-n shifting, the enhanced performance was discussed in correlation with La doping-triggered changes in the nanostructural and surfacial properties of the films. We validated the proposed technique by producing similar sensors and performing multiple replicates to ensure consistency and reproducibility. We also introduced the fill factor concept into the gas sensor field as a new trustworthy parameter that could improve sensor performance assessment and help rate sensors based on deviation from ideality.
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    Application and comparison of theoretical approaches to mechanical properties of bulk YBCO-358 ceramic superconductors
    (2024) Bulut, Fatih
    Co nanopowder substituted YBCO-358 (Y3Ba5Cu8-xCoxO18-δ) bulk ceramics were prepared with weight ratios of x=0, 0.05, 0.10 and 0.15 using the SSR (Solid State Reaction) method in tube furnace at oxygen (O2) atmosphere. The impact of partially replacing Cu with Co impurities on the load-independent (or true) microhardness parameters of YBCO-358 have been examined using five theoretical models: Meyer's law (ML), Hays-Kendall (HK), elastic/plastic deformation (EPD), proportional sample resistance (PSR) and the last is indentation-induced cracking (IIC). These models were applied to results that obtained by experimental microhardness tests conducted at various loads. Vicker’s Microhardness analysis shown that each samples has reverse indentation size effect (RISE). The results showed that partial Co nanoparticle doping affected the mechanical behavior/properties of produced YBCO-358 ceramics due to an enhance in crystal structural defects. Additionally, the degradation of the crystal structure led to a reduce in the typical RISE behavior of YBCO-358 superconducting ceramics. It has found that the IIC model was the best fit as it was the only one that produced results close to the saturation point, while the other models did not.
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    Chemical precursor-dependent dual effect of doping on the gas-sensing performance of metal oxide semiconducting materials
    (Elsevier Science Sa, 2024) Ajjaq, Ahmad; Bulut, Fatih; Ozturk, Ozgur; Acar, Selim
    In this study, we report a chemical precursor-dependent dual effect of doping on the gas-sensing performance of metal oxide semiconducting materials. Our findings challenge the conventional notion that optimal doping consistently enhances gas-sensing properties. Acetate and nitrate salts were used as chemical precursors, lanthanum (La) was used as a dopant, and ZnO was used as a semiconducting material. All materials were synthesized under identical conditions by a two-step process involving dip coating and hydrothermal methods. Gas-sensing results demonstrated an improvement in the performance of the acetate-based doped film and a decline in that of the nitrate-based doped film compared to their respective pure counterparts. Among the produced sensors, 1 wt% La-doped ZnO sensor produced by the acetate precursor proved to be convenient for usages in real markets. It showed superior performance with a high response (62) at a relatively low operating temperature (150degree celsius) towards 50 ppm of NH3 gas. The sensor also demonstrated exceptional baseline stability, high short-term and long-term consistency, good selectivity, and strong tolerance to humidity (up to 70 RH%) with slightly slow adsorption-desorption rates. The dual effect was discussed with respect to dopant- and precursor-induced variations in structural and surficial characteristics, revealed by XRD, Raman, FESEM, AFM, and XPS. The discussion delved deeper into the role of chemical precursors on nanostructure growth and, for the first time, illuminated a temperature-dependent complex gas-sensing principle governed by the detected p-n shift of the semiconductor type of the sensing elements, confirmed by Hall effect.
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    Design of New Generation Low-Cost Dip Coating Device and Performance Tests in ZnO Thin Film Production
    (Sakarya University, 2024) Bulut, Fatih; Günel, Eda
    In this study, a dip coating device was designed using low-cost materials and performance tests were performed. The dip coating method is an efficient coating technique used to dip samples into chemical solutions and produce thin films. The designed system provides precise movement in the vertical axis with a stepper motor, while a heating unit can be used to apply heat treatment during the coating process. The device controlled by Arduino allows the user to adjust the number of dips, waiting times and movement speed. In order to test the operation of the system, ZnO thin films were produced, and these films were evaluated with XRD, SEM and UV-spectrophotometer analyses. As a result of the analyses, it was determined that the structural and optical properties of the films produced by the device were in accordance with the data in the literature. These results prove that the designed dip coating system is successful and functional. © 2024, Sakarya University. All rights reserved.
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    Effect of Co/Cu partial replacement on fundamental features of Y-123 ceramics
    (Springer, 2020) Ozturk, Ozgur; Nefrow, Abdul R. A.; Bulut, Fatih; Ada, Hakan; Turkoz, Mustafa B.; Yildirim, Gurcan
    This study is liable for the effect of sample production processes including the standard solid-state reaction (SSR) and classical sol-gel (SG) preparation methods on the fundamental characteristic features, namely electrical, superconducting, crystal structure quality, crystallinity, morphological, strength quality of grain boundary couplings, and interaction between the grains of YBa2Cu3-xCoxO7-delta (Y-123) advanced ceramic compounds within the weight ratio intervals x = 0-20%. The main heat treatments are exerted at two main steps: (I) annealing at 950 degrees C for 24 h in air medium conditions and (II) annealing at 500 degrees C during 5 h under the oxygen annealing ambient. The standard measurement methods such as powder X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, temperature-dependent electrical resistance, and Vickers hardness measurements are performed for the characterization of materials. It is found that the samples prepared at SSR route present much more superior characteristic features as compared to those fabricated at SG technique, being one of the most striking points deduced this work. In more detail, every material prepared crystallizes in the orthorhombic symmetry and exhibits the superconducting nature but considerable decrement in the critical transition temperatures. The onset and offset transition temperatures are noted to decrease regularly from 92.96 K (92.28 K) to 90.20 K (83.59 K); and 90.05 K (90.03 K) to 45.97 K (30.49 K) for the materials prepared by the SSR (SG) route. Similarly, the variation in the lattice cell and average grain size parameters confirm that the Co/Cu substitution damages Y-123 superconducting phase. Additionally, the Co/Cu partial replacement mechanism leads to increase significantly the Vickers hardness results. To sum up, the Co/Cu partial substitution (produced by either SSR or SG method) is plowed to improve the fundamental characteristic features for new, novel, and feasible market application areas of Y-123 cuprate ceramics in the universe economy.
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    Effect of Ni and Al doping on structural, optical, and CO2 gas sensing properties of 1D ZnO nanorods produced by hydrothermal method
    (Wiley, 2022) Bulut, Fatih; Ozturk, Ozgur; Acar, Selim; Yildirim, Gurcan
    In the present study, the one-dimensional ZnO nanorod structures are produced within the different nickel and aluminum molecular weight ratios of 0-7% using the hydrothermal method. It is found that the aluminum (Al) and nickel (Ni) impurities with different ionic radius, chemical valence, and electron configurations of outer shell cause to vary the fundamental characteristic features including the crystallinity quality, crystallite size, surface morphology, nanorod diameter, optical absorbance, energy band gap, resistance, gas response, and gas sensing properties. The structural analyses performed by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicate that the samples are found to crystallize in the hexagonal wurtzite structure. The presence of optimum nickel and aluminum in the crystal system improves considerably the crystallinity quality and surface morphology. Additionally, the combination of electron dispersive X-ray (EDX) and XRD results declare that the Ni and Al impurities incorporate successfully into the ZnO crystal structure. Moreover, the diameters of nanorod structures in 1D orientation are determined to be 80 nm or below. The hexagonal wurtzite-type ZnO nanorod structure prepared by 5% Ni has more space between the nanorods and thus presents higher response to the CO2 detection. Further, the optical absorbance spectra display that the band gap value is observed to decrease regularly with the increment in the doping level as a result of band shrinkage effect depending on the enhancement of mobile hole carrier concentrations in the crystal structure. In other words, the doping mechanism leads to vary the homogeneities in the interfacial charges, nanorod diameters, ZnO oxide layer composition and thickness. The last test conducted in this study is responsible for the determination of CO2 gas sensing levels. The obtained gas sensing results are further compared with each other and literature findings. It is observed that 5% Ni-doped sample provides more successful results than other samples in the sensing CO2 gas at the different concentrations. All in all, the paper establishing a strong methodology between doping mechanism and change in the fundamental characteristic features of hexagonal wurtzite-type ZnO with the aid of advanced microscopy techniques will become pioneering research to answer key questions in materials sciences and electronic research.
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    Evaluation of Monocrystalline and Polycrystalline Photovoltaic Panels in Sinop Province Conditions
    (2021) Karaağaç, Mehmet Onur; Ogul, Hasan; Bulut, Fatih
    Due to the increase in energy consumption and environmental pollution in recent years, countries have included renewable energy in their long-term energy policies by supporting researches to increase the usage diversity and performance of renewable energy sources. Solar energy, one of these renewable energy types, and its various applications are of great importance to increase the energy production diversity. In this context, evaluation of monocrystalline and polycrystalline photovoltaic panel performance was performed under Sinop climate conditions. In the first stage, the most suitable panel tilt for Sinop province was found by recording the voltage and current values of the panels at different panel angles. Then, in different days, the efficiencies of the panels were calculated using the determined optimum angle and compared with the literature. Finally, the effect of temperature change on the panels was evaluated. With this study, the most suitable panel type is determined for Sinop province and its surrounding conditions, thus preventing unnecessary investments and efficiency losses.
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    Investigation of gamma-ray radiation shielding properties of zinc borate and paraffin filled sheep wool biopolymer composites: Experimental and theoretical analysis
    (Pergamon-Elsevier Science Ltd, 2025) Karatas, Ozgul; Ercan, Hatice Unal; Altin, Mustafa; Ogul, Hasan; Bulut, Fatih
    The present study examines the potential of sheep wool biopolymer composites filled with zinc borate and paraffin wax additives as a gamma-ray radiation shielding material. The selected novel composite samples were prepared with varying proportions of additive materials (10, 20, 30, and 40 wt%) so that impact of the additive amount on radiation shielding could be properly analyzed. Evaluations of specimens were performed at different energy levels ranging from 20 keV to 1.3325 MeV with help of a NaI scintillation detector, MC simulation (GEANT4) and WinXCOM theoretical calculation code. Following the production of shielding samples, the characterization and structural evaluation was performed using X-Ray Diffraction (XRD) and field emission scanning electron microscope (FE- SEM /EDX) supported by EDAX energy dispersive X-ray spectroscopy. The results demonstrate that the incorporation of additives into composite materials enhances the gamma attenuation capacity. The optimal gamma shielding performance is achieved with a 40 wt% ZnB40 composition, which exhibits superior shielding efficacy at lower gamma-ray energies. The MAC value of ZnB40 at 20 keV is about 2.7343 times higher than one of ZnB10 while it is about 1.2675 times greater at 80.9 keV. Moreover, it can be safely said that ZnB40 material can be a suitable option for insulating dentist rooms or buildings that require the use of regular aprons.
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    Investigation on radiation interactions with some quenched alloys used in nuclear reactors
    (Pergamon-Elsevier Science Ltd, 2025) Ogul, Hasan; Yaz, Abuzer; Us, Hakan; Bulut, Fatih
    This study presents the investigation of the radiation interaction properties for SS304 and Incoloy 800H alloys, which are widely used in PWRs and HTGRs. First of all, theoretical and MC simulation evaluations are performed, then experiments are conducted for further analysis. The findings indicate no significant difference in mass attenuation coefficients (MAC) and gamma-ray radiation protection efficiencies (RPE) between the two alloys. Additionally, both SS304 and Incoloy 800H exhibit similar neutron shielding capabilities, with comparable effective removal cross-sections and numbers of transmitted neutrons at different neutron energies (0.025 eV, 100 eV and 4.5 MeV). The study also examines secondary radiation generated by neutron interactions. The impact of thermal treatment (300 degrees C, 500 degrees C, 700 degrees C and 1000 degrees C) and cooling approaches (quenching and selfcooling) on these alloys were further experimentally examined. Notably, thermal treatment changes the MAC values, particularly at 1000 degrees C, with SS304 showing a more distinct change than Incoloy 800H. Besides, quenched samples have higher MAC values compared to self-cooled samples, especially at 1000 degrees C. However, the microhardness values remained largely unaffected by heat treatment, except at 1000 degrees C, where both alloys exhibited reduced microhardness. The study underscores that there is no significant difference in microhardness between quenching and self-cooling techniques. These results provide valuable insights for enhancing the safety and efficiency of radiation shielding materials in nuclear reactors.
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    Novel 3D-Printed lead-free radiation protection apron in the medical X-ray and thermal neutron energy range
    (Pergamon-Elsevier Science Ltd, 2024) Ogul, Hasan; Gultekin, Batuhan; Yildiz, Hatice; Us, Hakan; Bulut, Fatih
    In this study, we employed 3D printing technology to fabricate poly lactic acid (PLA) polymer samples infused with gadolinium oxide nanoparticles at additive rates of 10% and 20%. The objective was to explore their potential as radiation shielding aprons within the medical X-ray and thermal neutron energy spectrum. To facilitate comparisons, a PLA polymer sample with no additive was also produced. The homogeneity and well-defined structures of the PLA samples were observed using SEM and EDS analyses. Additionally, the excellent thermal stability of the proposed test samples was reported. In terms of gamma-ray shielding, there is a remarkable consistency between experiment, theory and simulation outcomes with a maximum discrepancy of approximately 5%. P-PLA-Gd20 sample exhibits attenuation capabilities against X-rays to a level that could serve as an alternative to lead. Additionally, the thermal and fast neutron attenuation effectiveness of the prepared samples were determined. A shielding effectiveness of 100% against thermal neutrons was achieved using a 10 mm sample thickness and the P-PLA-Gd20 sample. The findings consistently highlight the efficacy of the proposed polymer sample with a 20% gadolinium oxide nanoparticle additive, positioning it as a viable and promising alternative to traditional lead aprons.
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    Potential use of ABS polymer reinforced with nanoparticle sized yttrium as radiation shielding material
    (Springer Heidelberg, 2024) Bulut, Fatih
    This study investigates the gamma-ray attenuation capabilities of ABS polymer reinforced with nano-sized yttrium particles. The analysis focuses on three key parameters: mass attenuation coefficient, half-value layer, and radiation protection efficiency. Utilizing a sol-gel process for polymer molding, various test samples were prepared and subjected to scanning electron microscopy (SEM) for surface structure examination. Then, experimental, theoretical, and simulation approaches are used to obtain gamma-ray shielding parameters. The base and additive materials are chosen as ABS polymer and yttrium nanoparticles, respectively, and the results revealed a consistent enhancement in gamma-ray attenuation characteristics with the incorporation of yttrium nanoparticles. These findings offer valuable perspectives for advancing the development of sophisticated radiation shielding materials, presenting potential applications across diverse fields including medical imaging, industrial processes, and nuclear technologies.
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    Production and investigation of 3D printer ABS filaments filled with some rare-earth elements for gamma-ray shielding
    (Korean Nuclear Soc, 2023) Gultekin, Batuhan; Bulut, Fatih; Yildiz, Hatice; Us, Hakan; Ogul, Hasan
    Radiation is the main safety issue for almost all nuclear applications, which must be controlled to protect living organisms and the surrounding materials. In this context, radiation shielding materials have been investigated and used in nuclear technologies. The choice of materials depends on the radiation usage area, type, and energy. Polymer materials are preferred in radiation shielding applications due to their superior characteristics such as chemical inertness, resistivity, low weight, flexibility, strength, and low cost. In the presented work, ABS polymer material, which is possibly the most commonly used material in 3D printers, is mixed with Gd2O3 and Er2O3 nanoparticles. ABS filaments containing these rare-earth elements are then produced using a filament extruder. These produced filaments are used in a 3D printer to create shielding samples. Following the production of shielding samples, SEM, EDS, and gamma-ray shielding analyses (including experiments, WinXCOM, GEANT4, and FLUKA) are performed. The results show that 3D printing technology offers significant enhancements in creating homogeneous and well-structured materials that can be effectively used in gamma-ray shielding applications.
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    Radiation shielding properties of the doped carbon fiber-reinforced epoxy composites
    (Pergamon-Elsevier Science Ltd, 2023) Erdem, Serkan; Bulut, Fatih; Ozcan, Mehmet Erbil; Ogul, Hasan; Yildiz, Yunus Onur
    In this study, the linear attenuation coefficients of the doped carbon fiber-reinforced epoxy composites (Boron Oxide (B2O3), Lead Monoxide (PbO) and Zinc Borate (2ZnO 3B2O3 3H2O)) for the gamma radiation are inves-tigated with the help of the High Purity Germanium (HPGe) Detector. The doped carbon fiber-reinforced epoxy composites were prepared with different proportions of additive materials (10, 20, and 30 wt%) so that impact of the additive amount on radiation shielding could be properly analysed. The specimens were tested at 7 different energy levels ranging from 82.0 to 1332.0 keV with the use of HPGe detector. Further on, the effect of additive materials on mechanical properties was also examined. Findings indicate that all additives into composite ma-terials improve the gamma attenuation ability, and the best gamma shielding characteristic is obtained in the case of 30 wt% Lead Monoxide sample. On the other hand, 10 wt% additive materials provide increase in stiffness compared with undoped samples.
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    The Investigation of CO2 Gas Sensing Performance of ZnO Nanorods Growth on RF Sputtered Seed Layer
    (2023) Bulut, Fatih; Ozturk, Ozgur; Acar, Selim
    In this study, one-dimensional ZnO nanorod structures with different ratios of nickel doping were produced using the hydrothermal method. The presence of nickel doping in different ratios caused variations in the fundamental characteristics of the nanorods that grew on the RF sputtered seed layer, such as crystallinity quality, morphology, diameter of the nanorods, band gap energy, resistance of the sample, and CO2 gas sensing. Produced samples were found to form like hexagonal rods and crystallize in a wurtzite structure, and the ratio of nickel doping improved the crystallin quality and the morphology of sample surface. This study showed that the 5% nickel doped sample provided the most effective results in sensing CO2 gas at different concentrations. Overall, the study provided valuable insights into the relationship between doping system and the basic characteristics of wurtzite-type hexagonal ZnO.