Gazi University Journal of Science Part A: Engineering and Innovation最新文献

{"title":"Characterization of Hot Extruded Hybrid Composites Al 2024 Metal Matrix Reinforced with TiO2 and ZrO2","authors":"Ayşenur Pektaş, Okan Can Ebetürk, U. Gökmen","doi":"10.54287/gujsa.1189756","DOIUrl":"https://doi.org/10.54287/gujsa.1189756","url":null,"abstract":"In this study, the microstructure and mechanical properties of Al 2024 powder, the prominent type of Al 2XXX series aluminum alloys widely used in the aerospace industry, and TiO2 and ZrO2 reinforcement elements used to improve material properties were investigated. Each reinforcement element is included in the material at the rate of 10%. For hybrid composite sample production, 10% hybrid composite material was procured by adding each reinforcing element equally. For each sample, powders were mixed in a 3D mixer to ensure an equal distribution of matrix powder and reinforcement elements in the samples. The samples were churned out by subjecting the two-stage them to a one-way hot press process. The furnace temperature was kept at 600 o C to preserve samples. Density and microstructure analyses were performed on the formed samples, and the results were evaluated. After all, the Archimedean density measurement method was used to obtain final densities, these samples were taken to bakelite for optical images, then scanning electron microscope (SEM) and Brinell hardness of the samples was measured. The cross-fracture strength test was completed to analyze each sample’s microstructural behavior. Finally, the theoretical radiation shielding properties of each sample were investigated. The Phy-X/PSD program was used to examine the radiation permeability properties. According to the test and analysis results, the effect of reinforcement elements on the material was determined. As a result, the highest hardness value measured was 97.5 HB at the 10% ZrO2 -reinforced MMCs. However, the relative density of the hybrid composite is better than ZrO2-reinforced MMCs. Thus, the best cross-fracture strength measured was 635 MPa in 10% hybrid MMCs. The radiation shielding parameters showed that the 10% ZrO2 -reinforced MMCs are best for shielding. Therefore, the second reasonable material for radiation shielding is hybrid reinforced materials. In the final decision, hybrid composite materials became prominent because the distinctive features of each material enhanced the samples.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121742354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Computational Study of the Adsorptive Separation of Methane and Hydrogen in Zeolite Templated Carbons","authors":"C. U. Deniz","doi":"10.54287/gujsa.1205356","DOIUrl":"https://doi.org/10.54287/gujsa.1205356","url":null,"abstract":"Combustion of conventional energy sources produces pollutants such as SOx, NOx, and CO; the use of hydrogen and methane can eliminate these harmful emissions. In fuel cell technology and other uses, hydrogen must be refined by extracting methane from the methane/hydrogen combination, produced via dry or steam reforming. This study investigates the adsorption and separation capabilities of recently discovered zeolite-templated carbons (ZTCs) for binary mixtures consisting of hydrogen and methane. To assess the adsorption and separation performances of these carbon-based nanostructures, grand canonical Monte Carlo (GCMC) simulations were used. The simulation results revealed that AFY (|(C6H15N)3(H2O)7|[Co3Al5P8O32]) and RWY (|(C6H18N4)16| [Ga32Ge16S96]) structures could be viable alternatives for applications involving adsorptive gas separation based on selectivity and the CH4 uptake capacity. The selectivity of AFY was calculated to be 176, while its capacity to uptake CH4 was found to be 2.57 mmol/g, the selectivity of RWY was calculated to be 132, and its CH4 uptake was 3.49 mmol/g.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"262 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116062409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Electronic and Magnetic Properties of 4d Transition Metals Based NbAl2F4 and TcAl2F4 Spinels","authors":"E. G. Özdemir","doi":"10.54287/gujsa.1185023","DOIUrl":"https://doi.org/10.54287/gujsa.1185023","url":null,"abstract":"Half-metallic properties of NbAl2F4 spinel and semiconductor characteristics of TcAl2F4 spinel were investigated with the help of the WIEN2k program. NbAl2F4 spinel shows a metallic character in the up-electron states, while it has a semiconductor nature in the down-electron states. In NbAl2F4 spinel, the Eg bandgaps were calculated in GGA and GGA+mBJ 1.551 eV and 1.622 eV, respectively. The EHM half-metallic bandgaps were obtained 0.410 eV and 0.422 eV, respectively. In the up-spin states of TcAl2F4 spinel, Eg values were obtained 1.199 eV and 1.447 eV for the GGA and GGA+mBJ methods, respectively, while they were obtained 1.281 eV and 1.519 eV in the down-spin states, respectively. When GGA+mBJ is used, it is easily observed that the semiconductor characters increase. Total magnetic moments of NbAl2F4 and TcAl2F4 spinels were calculated 6.00 µB/cell and 10.0 µB/cell, respectively. When both electronic and magnetic moment values are carefully examined, NbAl2F4 and TcAl2F4 spinels can be used as alternative compounds in spintronic applications.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130567021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Investigation of Hydro-Mechanical Soil Properties of a Slope Failure","authors":"S. Durukan, Ender Başarı","doi":"10.54287/gujsa.1141808","DOIUrl":"https://doi.org/10.54287/gujsa.1141808","url":null,"abstract":"A sudden slope failure occurred in Manisa possibly due to the effect of water infiltration because of a slightly damaged sewage pipe. Considering that there was no other evidence such as rainfall or any loading conditions to trigger the slope failure, a laboratory investigation on the soil’s unsaturated hydro-mechanical properties was initiated. Slopes are naturally unsaturated soils, and they may lose their stability with increased saturation degrees with water infiltration. Thus, for a proper investigation, the unsaturated hydro-mechanical properties of soils should be determined. The results presented in this study are focused on determining the key parameters to evaluate the slope failure for unsaturated soil conditions. In this regard, hydraulic conductivity and suction characteristics and the shear strength parameters were determined as well as the classical geotechnical properties of the soil. Classification of soil was determined as silty sand which is known to have slight to moderate suction stresses and mostly affected suddenly by water infiltration. A flexible-wall permeability test was run with a falling head procedure and the saturated hydraulic conductivity of the soil sample was measured as 1x10-7 m/s. Suction characteristics were detected by filter paper method, besides, the soil water retention curve of the soil was constructed. The maximum matric suction of the soil was measured as 2887 kPa for an air-dried sample. Following, the shear strength parameters were measured by conventional direct shear test for both dry and soaked conditions. Finally, the friction angle due to suction was calculated to be 1.7 degrees from the results of dry and saturated shear strength parameters.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116114530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Experimental and Monte Carlo Efficiencies of 0.5g/cc Epoxy Matrix Marinelli Source with Multiple Radioactive Nuclides","authors":"G. Aksoy, Hasan Ünlü, Nilgün Orhan, M. Bölükdemir","doi":"10.54287/gujsa.1119622","DOIUrl":"https://doi.org/10.54287/gujsa.1119622","url":null,"abstract":"Using the gamma spectroscopy system, it can be determined whether environmental samples or standard radioactive sources are radioactive, and from which elements their radioactivity originates. The purpose of Monte Carlo (MC) simulation is to model a real-life system with its inputs and evaluate the outputs with real results. This study calculates the experimental efficiency of a p-type HPGe detector using a 0.5 g/cc Epoxy Matrix Marinelli beaker and compares these results with GESPECOR and PHITS MC Simulation programs. Thus, the thickness of the dead layer, which thickens over time and affects the detector efficiency, was determined from the most compatible result of the MC calculations made repeatedly at various alternative thicknesses to the experimental results. For 1.5 mm dead layer thickness, less than 2 % error was found between the test and MC results, especially at energies above 165 keV. As a result, it was determined that the dead layer thickness of the detector reached 1.5 mm with an increase of 114 % after its production. The current value of the dead layer thickness of each detector should be checked, as the efficiency affects the determination of the activity.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114922783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effectuality of the Frequency Levels on the C&G/ω–V Data of the Polymer Interlayered Metal-Semiconductor Structure","authors":"Jaafar Abdulkareem Mustafa Alsmael, Nuray Urgun, S. Tan, H. Tecimer","doi":"10.54287/gujsa.1206332","DOIUrl":"https://doi.org/10.54287/gujsa.1206332","url":null,"abstract":"Voltage and frequency dependent of capacitance and conductivity versus voltage (C&G/ω–V) qualifications of Al/(ZnFe2O4-PVA)/p-Si structure was compared and examined at lower and higher frequencies as 10 kHz and 1 MHz, respectively. The negative capacitance (NC) is a phenomenon that occurs at low frequencies and is primarily caused by minority carrier injection, series resistance (Rs), and surface states (Nss). Because of the specific density distribution and relaxation times of Nss, NC acts different behavior at lower and higher frequency levels and loses its effectiveness with increasing frequency. Also, the fluctuations in C and G/ω were ascribed to doping concentration, surface states loss charges, and interlayer thickness. Nss was acquired using the low-high frequency capacitance method (CLF-CHF), and the forward biased C−2 vs V graphs (at 10 kHz to 1 MHz) were used to determine the Fermi level (EF), barrier height (ΦB), and concentration of doped acceptor atoms (NA). Accordingly, it has been detected that C and G/ω are highly dependence on biases and frequencies. Then again, the polarizations and surface states effect are barely perceptible at extremely higher frequency levels. Thus, polarization and Rs stand out as important parameters that should be taken into account when examining the basic parameters of electronic devices.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128746188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of the Hot Water Parameter on the Structural and Optical Properties of SILAR-Deposited ZnO Samples","authors":"Salih Akyürekli, Tugba Çorlu, İ. KARADUMAN ER, S. Acar","doi":"10.54287/gujsa.1180316","DOIUrl":"https://doi.org/10.54287/gujsa.1180316","url":null,"abstract":"In this study, ZnO thin films were grown by the Successive Ionic Layer Adsorption and Reaction (SILAR) method. The SILAR method is a chemical solution-based method consisting of 4 steps: solution, hot water, air and deionized water. Our main goal is to examine the changes in SILAR method production by changing the hot water parameter from these steps. It is widely known that chemical synthesis methods and their relative parameters have a crucial effect on the size of the produced thin films, surface area/volume ratio, porosity as well as defects in the film which in turn affect the morphology. All parameters were kept the same and changes were made in the hot water step, in addition to the classic 90°C hot water step, constant temperature ultrasonic cleaner at 40 ºC, an ultrasonic cleaner at room temperature, and an ultrasonic breaker at room temperature are used instead of the hot water step. For this purpose, alternative devices such as ultrasonic cleaner and ultrasonic breaker were used to break the unwanted weak bonds at lower temperatures during production. The structural, morphological, optical and electrical properties were characterized and the results were investigated in detail.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128133915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation and Development of Polarographic Method for Pb (II) and Cd (II) Analyses in Oils","authors":"Şükrü Kalayci, S. M. Muhammet, B. S. Çevrimli","doi":"10.54287/gujsa.1190172","DOIUrl":"https://doi.org/10.54287/gujsa.1190172","url":null,"abstract":"In this study, Differential Pulse Polarography (DPP) method was preferred of Cd (II) and Pb (II) levels, which have toxic effects. This method was applied to determine Cd and Pb levels in cold-pressed olive oil brought from 5 different provinces of Turkey. The samples were dissolved in microwave digestion using concentrated HNO3 and H2O2. Analyses were carried out in acetate buffer (pH 4) to which EDTA was added. The LOD for Cd and Pb was found as 0.74, 0.52 µg L-1 and the LOQ was 0.96, 0.82 µg L-1. Additions were made from standard Cd and Pb solutions and the % recovery values were measured as 98 and 99. The relative standard deviation (RSD, %) was found < 5. This method was found to be sensitive to the analyses of two toxic elements in cold pressed olive oil.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117293538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Microstructure and Tribological behavior of WE43/nano B4C Composites Produced by Spark Plasma Sintering","authors":"Ufuk Taşci, B. Bostan","doi":"10.54287/gujsa.1214668","DOIUrl":"https://doi.org/10.54287/gujsa.1214668","url":null,"abstract":"In this study, composite samples of WE43 (Mg-4Y-3RE-Zr) reinforced with nano-B4C particles in different ratios (0.5 and 2 wt.%) were prepared by spark plasma sintering (SPS). The powders were mixed in a 3-dimensional ball mill at 300 rpm. The mixed powders were then hot pressed under 35 MPa pressure at 525 °C for 6 min. XRD and FESEM-EDS instruments were used to characterize the composite samples. Microhardness and wear tests were performed to designate the mechanical properties. It was found that the highest hardness occurred in the composite sample with 2% nano-B4C composites. It was also found that tribological properties improved with the increase of nano-B4C content.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132448043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Diluent Amount on Properties of Porous NiAl","authors":"Gülizar Sariyer, H. E. Çamurlu","doi":"10.54287/gujsa.1174783","DOIUrl":"https://doi.org/10.54287/gujsa.1174783","url":null,"abstract":"Porous NiAl parts were formed by using Ni and Al elemental powders, preformed NiAl as diluent and NaCl particles as space holder (SH). The aim of utilizing preformed NiAl (30%-40%) as a diluent was to preserve the shape of the products. The amounts of the SH NaCl particles in NiAl were 25-50-75 vol.% and their sizes were in 300-500 µm range. Porous NiAl samples were prepared by volume combustion synthesis (VCS). The adiabatic temperatures of the Ni+Al mixtures having 30 and 40% diluent NiAl were calculated as 1638.9 and 1460.8°C, respectively. Formation of NiAl phase was verified by XRD analyses. In the green pellets, the total porosity amount was higher than the added NaCl amount. Also it was slightly higher in the product pellets than in the green pellets before VCS. Compressive strength and microhardness values of the samples which contained 30% diluent NiAl were higher than the samples which contained 40% diluent. Average compressive strength values of the products that were obtained by 25% NaCl and 30 and 40% diluent NiAl additions were 112.0±29.5 and 66.0±20.5 MPa, respectively.","PeriodicalId":134301,"journal":{"name":"Gazi University Journal of Science Part A: Engineering and Innovation","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121527247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}