06. Meslek Yüksekokulları

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Citation - WoS: 27
Citation - Scopus: 34
Analysis of Effect Factors on Thermoelectric Generator Using Taguchi Method
(ELSEVIER SCI LTD, 2020) Terzioğlu, Hakan
Due to technological developments in recent years, the need for domestic and industrial electric power is increasing day by day. Alternative energy resources have become more important to reduce production costs by converting waste energy into electricity. In this study, a research was carried out to increase the efficiency and on the factors which were effective in Thermoelectric Generators (TEG) used in the production of electrical energy by using thermal sources from alternative energy sources. In this study, the effects of heat transfer performance of the materials (copper, aluminum and brass) on which thermal water is carried, and the effects of water pressure and velocity on the performance of TEGs were investigated. Taguchi method was used to determine the performance effects in the most accurate way. Taguchi method used three levels with three factors: material (copper, aluminum and brass), engine speed (I, II and III) and water pressure (1-2.5-3.5 bar). In addition, in the Taguchi method, the orthogonal array was used and the optimum operation time was significantly reduced. In this study, TEG1-12706 and TEG1-12710 were performed in 2 different TEGs. 27 experiments were carried out for each TEG under different materials, speed and pressure of water with the experiment set up in this study. When the test results were analyzed by Taguchi method, it was determined that the material was the most important factor in determining the output power and efficiency in the production of electrical energy by using TEG (approx. 89%) and it was seen that the pressure and engine speed had almost no role. (C) 2019 Published by Elsevier Ltd.
Ball Throwing Machine Design To Develop Footballers’ Technical Attributes
(2021) Arslan, Cemile; Arslan, Mustafa; Yalçın, Gökhan; Kaplan, Turgut; Kahramanlı, Humar
For a football player to perform well in football, it is necessary to improve his technical and tactical skills. Improving these skills is enabled with the repetition of the same positions that the football player has the ball. The repetitions of these same positions can be performed with the aid of a machine. In this study, a football throwing machine design that can provide direction and velocity for the ball in a repeatable and controllable manner is generated for full educational evaluation. Ball loading canister on the ball throwing machine enabled to use of many balls. There are a couple of ball throwing wheels both are made of polyurethane material and have a concave surface. These wheels are mounted on a body for axial rotation on common ground. Each wheel’s rotation speed can be adjusted individually. To determine the horizontal-vertical direction of movement of the ball, two linear actuators are used. Ball’s velocity, direction, orbit, and throwing laps are controlled electronically. All controls concerning ball throwing are carried out via Delta PLC (Programmable Logic Controller) and HMI (Human Machine Interface) panel. A user interface is developed for controls made via PLC. Owing to the interface, different training plans are designed by handler or trainer via operator panel, and footballer is provided to train in various densities. To prevent toppling tripod system, and to carry easily a towing arm is used. The machine can work with an accumulator or feed directly from the grid circuit.
Determination of Optimal Modulation Amplitude for Electron Spin Resonance (esr) Dating and Dosimetry Studies of Tooth Enamel
(2020) Karataş, Özgül
Fossil remains, which provide important information about past life and ecology, are especially important in natural history and life evolution. Recently, many interdisciplinary dating studies have been conducted and many different techniques have been used to investigate the data obtained in this field. Electron Spin Resonance (ESR) (or alternatively, Electron Paramagnetic Resonance, EPR) is one of the methods used in absolute dating and dosimetry studies. It is based on determination of the radiation-centered radicals obtained from the radiation dose absorbed by irradiated materials. One of the important problems in dosimetry and dating studies performed with ESR method is the dependence of experimental parameters on the accumulated dose. The accumulated dose value is effective in determining the actual result of the dating and dosimetric samples. This value is influenced from the stability of the ESR centers, experimental stages, sample preparation or measurement processes. In this study, how the modulation amplitude parameter affects ESR signal intensity in ESR dating and dosimetry studies of tooth enamel investigated. The selective archaeological animal tooth enamel sample was used from the archaeological site of Köşk Höyük, in Turkey for experimental studies. This sample was prepared with combined processes of mechanical and chemical treatment of tooth in laboratory. Tooth enamel sample was irradiated by 60Co gamma-ray source in dose of 1kGy. After irradiation, ESR spectra were recorded at different modulation amplitude values at room temperature using X-band ESR Spectrometer. According to the results obtained, the most suitable modulation amplitude values for ESR measurements of tooth enamel sample examined in the study.
Citation - WoS: 18
Citation - Scopus: 19
Development of Highly Luminescent Water-Insoluble Carbon Dots by Using Calix[4]pyrrole as the Carbon Precursor and Their Potential Application in Organic Solar Cells
(Amer Chemical Soc, 2022) Coşkun, Yağız; Ünlü, Fatma Yelda; Yılmaz, Tuğbahan; Türker, Yurdanur; Aydoğan, Abdullah; Kuş, Mahmut; Ünlü, Caner
Carbon dots (CDs) are carbon-based fluorescent nanomaterials that are of interest in different research areas due to their low cost production and low toxicity. Considering their unique photophysical properties, hydrophobic/amphiphilic CDs are powerful alternatives to metal-based quantum dots in LED and photovoltaic cell designs. On the other hand, CDs possess a considerably high amount of surface defects that give rise to two significant drawbacks: (1) causing decrease in quantum yield (QY), a crucial drawback that limits their utilization in LEDs, and (2) affecting the efficiency of charge transfer, a significant factor that limits the use of CDs in photovoltaic cells. In this study, we synthesized highly luminescent, water-insoluble, slightly amphiphilic CDs by using a macrocyclic compound, calix[4]pyrrole, for the first time in the literature. Calix[4]pyrrole-derived CDs (CP-DOTs) were highly luminescent with a QY of over 60% and size of around 4-10 nm with graphitic structure. The high quantum yield of CP-DOTs indicated that they had less amount of surface defects. Furthermore, CP-DOTs were used as an additive in the active layer of organic solar cells (OSC). The photovoltaic parameters of OSCs improved upon addition of CDs. Our results indicated that calix[4]pyrrole is an excellent carbon precursor to synthesize highly luminescent and water-insoluble carbon dots, and CDs derived from calix[4]pyrrole are excellent candidates to improve optoelectronic devices.
The Effect of Coating Parameter of Active Layer on Performance of Polymer Solar Cells
(2022) Yenel, Esma
In this study, Glass / ITO / PEDOT / Polymer / Al organic solar cell structures were obtained by using glass/indium doped tin oxide (Glass/ITO) transparent metal oxide substrates, PEDOT:PSS and P3HT:PCBM polymer photoactive layer and their performance depending on spin rate and coating technique were investigated. The polymer layer was coated using the spin coating method. Al metal was coated by physical vapor deposition method. By keeping the concentration of the photoactive layer constant, the effects of different spin coating rates, beside static and dynamic coating technique on the power conversion efficiency of the cells and their stability were compared. Electrical characterization of organic solar cells was performed under a solar simulator in a glove box system. By applying voltage between -0.5 V and +1.5 V, I-V (current-voltage) measurements of the solar cells were taken in the light and dark. The power conversion efficiencies of organic solar cells coated at 800rpm, 1000rpm and 2000rpm spin coating speeds, respectively, were observed to be 2.34%, 2.08% and 1.98%.When the average efficiency values considered, static coating at 800 rpm gives more reproducible results in comparison with the other average efficiency values. The average efficiency values for static coating at 800 rpm is observed to be %2.
Citation - WoS: 13
Citation - Scopus: 13
Electrical Behaviors of the Co- and Ni-Based Poms Interlayered Schottky Photodetector Devices
(Wiley, 2022) Yıldırım, Murat; Kocyigit, Adem; Torlak, Yasemin; Yenel, Esma; Hussaini, Ali Akbar; Kuş, Mahmut
Polyoxometalates (POMs) are attractive materials for various applications such as energy storage, catalysis and medicine. Here, Co and Ni-based POMs are chemically synthesized and characterized by X-ray diffractometer (XRD) and Fourier transform infrared spectroscopies (FT-IR) for structural characterization. While the morphological behaviors are analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM), the optical properties are investigated by UV-Vis spectrometer. Electrochemical characterizations are carried out by cyclic voltammetry to determine oxidation levels of the metal centers in the POMs. The CoPOM and NiPOM are inserted in between the Al metal and p-Si semiconductor to obtain Al/CoPOM/p-Si and Al/NiPOM/p-Si Schottky-type photodetector devices. Current-voltage (I-V) and current-transient (I-t) measurements are employed to understand the electrical properties of the Al/CoPOM/p-Si and Al/NiPOM/p-Si devices under dark and various light power intensities. The devices exhibit phototransistor like I-V characteristics in forward biases due to having POMs active layers. Various device parameters are extracted from the I-V measurements and discussed in details. I-t measurements are performed to determine various detector parameters such as responsivity and specific detectivity values for under 2 V and zero biases. The Al/CoPOM/p-Si and Al/NiPOM/p-Si Schottky-type photodetector devices can be employed in optoelectronic applications.
Gama Işınları ile Işınlanmış Yeni Bir Isoquinoline Sulfonamide (c17h20brno3s) Maddesinin X-bant Epr Çalışması
(Konya Technical University, 2020) Karataş, Özgül; Ceylan, Yusuf
Kaynaşık bir heteroksil bileşiği olan yeni epoxyisoquinoline sulfonamide maddesi (I), (4aS,7S,8aR)-8a-bromo-7-methyl-2-tosyl-2,3,4,7,8,8a-hexahydro-1H-4a,7-epoxyisoquinoline, yeşil ve kademeli bir süreç ile sentezlendi. Daha sonra doz hızı of 0.981 kGy/h olan 60Co-gama (?) kaynağı ile oda sıcaklığında 72 saat ışınlandı. I bileşiğinin EPR spektrumları, 150-340 K sıcaklık aralığında X-bant EPR spektrometresi kullanılarak manyetik alanda üç farklı yönelimde kaydedildi. Elde edilen sonuçlara göre, örneğe ait izotropik spektrumların olduğu görüldü ve C ?H_3 H radikalinin varlığı gözlemlendi. Sonuçlar, Bruker WinEPR-Simfonia programı kullanılarak fit edildi. Radikalin aşırı ince yapı sabiti (A) ile deneysel izotropik spektroskopik değeri (g) hesaplandı.
Citation - WoS: 4
Citation - Scopus: 2
The Investigation of Structural and Magnetic Properties of Er2-Xcoxo3 Nano-Oxides
(Springer, 2022) Heiba, Zein K.; Arda, Lutfi; Doğan, Nurcan; Karatas, Ozgul; Mohamed, Mohamed Bakr
The sol-gel technique was used to synthesize Er2-xCoxO3 (0.0 <= x <= 0.30) mixed oxides to analyze structural and magnetic properties. The Rietveld analyses show that Er2-xCoxO3 nanoparticles up to x = 0.1 have single phase, for x >= 0.2 Co3O4 phase appears. Preferential cationic distribution between the non-equivalent sites 8b and 24d is found for all samples. A systematic variation is found in the average maximum strain with composition x. The magnetic analysis showed that super-paramagnetism is the reason of S-shaped hysteresis loops and also non-zero magnetic moments. Both Mr and Ms increased with increasing concentration of Co+2.
Citation - WoS: 7
Citation - Scopus: 5
Investigation on the Cost-Effective Optimal Dimensions of a Solar Chimney With the Bees Algorithm
(Springer Heidelberg, 2022) Ünal, Recep Emre; Güzel, Muhammed Hüseyin; Sen, Muhammed Arif; Köse, Faruk; Kalyoncu, Mete
Solar chimney systems which consist of three main parts (collector, chimney, turbine) are one of the main thermal methods that produce electricity using solar energy. In a solar chimney, the high-power generation that can be obtained by increasing the design dimensions can also cause ineffective high investment costs. In this study, differing from the traditional design approach, a heuristic optimization method based on the Bees Algorithm is present to obtain the optimum design parameters (the chimney and collector dimensions) that are provided the more effective solutions. It is made for 3 configurations in order to prove the accuracy of the optimization study using different algorithm parameters. By using the obtained mathematical equations and the defined non-currency investment cost unit for a traditional solar chimney, the optimum design parameters that can provide more power output with acceptable costs are investigated. Two main objectives are taken into consideration namely maximizing efficiency of solar chimney system and minimizing investment cost. In the optimization process, within the ranges determined for the decision variables, the maximum and minimum dimensions are determined as 1293.05-1330.47 m for the collector diameter, 94-99 m for the chimney diameter and 783-792 m for the chimney height. The obtained results showed that this open to develop approach proposed within the scope of the study can be useful in the optimal design of solar chimney systems.
Mathematical Modeling of Thermoelectric Generator by Regression Analysis
(2018) Ağaçayak, Abdullah Cem; Terzioğlu, Hakan; Neşeli, Süleyman; Yalçın, Gökhan
As countries grow, their need and demand for energy grow as well. The development of the technology and industry, which come to exist due to the growth of the country, a brings about a rise in energy consumption, as well as increasing the damage to the environment. Therefore, as the environmental and energy-related issues started to emerge more and more, we have seen an increase in the number of studies on energy production and its effects on the environment. Such studies highlight the renewable energy sources among the non-polluting alternative energy sources. Geothermal energy, particularly, shines out among the other renewable energy sources. It is a clean energy source that has been sustained since the Earth was formed. This study focuses on the design of a device named thermoelectric generator (TEG) that converts a renewable energy source, geothermal energy, directly into electric energy. Hence, we ran a simulation of a regression analysis and mathematical model on the thermoelectric modules TEC1-12706 and TEC1-12710, which can easily be found on the market, and then crosschecked the simulation results of different temperature, pressure, and water flow with experiments. The values for current, voltage, power, hot and cold surface temperatures, and the temperature difference between hot and cold surfaces were constantly monitored and recorded. The results of the experiment were compared using the regression analysis method. For the device TEC1-12706, error percentage of 9 experiments was 16.52% while it was 9.70% for TEC1-12710. At 90°C temperature difference, for TEC1-12706, output voltage was Vmax = 2.03V, output power Pmax = 2.17W, and efficiency 32.15%. For TEC1-12710, output voltage was Vmax = 2.11V, output power Pmax = 3.42W, and efficiency 38.53% [1,2].
Sandviç Tasarımı İçerisindeki Termoelektrik Jeneratörde Elekrtrik Enerjisinin Analizi
(Konya Technical University, 2020) Terzioğlu, Hakan; Ağaçayak, Abdullah Cem
Son zamanlarda enerjinin gittikçe artan öneminden dolayı, araştırmacılar ve sanayi, enerji sisteminin verimliliğini artırarak enerjiyi daha iyi yönetmek istemektedirler. Bu nedenle elektrik enerjisini sağlamak için alternatif enerji kaynaklarına yönelim başlamıştır. Alternatif enerji kaynaklarından ise yenilenebilir enerji kaynaklarına olan ilgi her geçen gün artmaktadır. Güneş, Rüzgâr ve Termal kaynaklar yenilenebilir enerji kaynaklarının öne çıkanlarıdır. Günümüzde termal kaynaklardan seracılık, balık yetiştirme, termal tesisler, şehir ısıtması ve elektrik üretimi gibi birçok alanda faydalanmaktayız. Günümüzde termal suyu kaynağından faydalandığımız yere taşırken, etrafına yaydığı ısıyı elektrik enerjisine dönüştürebileceğimiz bilinmektedir. Bu çalışmada yenilenebilir enerji kaynaklarından termal kaynaklar kullanılarak, elektrik üretiminde termal suyun taşındığı malzemenin türünün ve Termoelektrik Jeneratörün (TEG) yerleşim şeklinin farklı iki Termoelektrik Modülün (TEM) verimi üzerindeki etkisi incelenmiştir. Sıcak ve soğuk su Bakır, Alüminyum ve Pirinç malzemelerinden oluşturduğumuz sandviç bloklardan geçirilerek TEG’de üretilen güç üzerindeki analizi gerçekleştirilmiştir. TEG olarak da TEC1-12706 ve TEC1-12710 malzemeleri kullanılmıştır. Yapılan deneysel çalışmalar sonucunda termal suyun geçtiği malzemenin türünün ve sıcak/soğuk suyun sandviç plakalardan geçme sırasının hem TEC1-12706’nın hem de TEC1-12710’nun ürettiği güç üzerinde etkili olduğu görülmüştür.
Sepiolite Enhances Biomineralization Activity of the Cementoblasts
(2020) Hakkı, Sema; Bozkurt, Şerife Buket; Yenel, Esma; Kuş, Mahmut
Aim: The inductive potentials of graft materials are important for regenerative therapies. Thus, this study was conducted using cementoblasts (OCCM-30) tooth root lining cells to determine whether sepiolite affected proliferation, mRNA expressions of genes associated with cementum/bone and biomineralization. Materials and Methods: The media containing released components of sepiolite (100 mg/ml ratio; waited 72 hrs in 5%FBS containing media) were used for cementoblast’s treatments. Proliferation of the cells was evaluated using a real-time cell analyzer (RTCA) for 170 hrs. After total RNA isolation on days 3 and 6, cDNA synthesis was performed. Bone sialoprotein (BSP), osteocalcin (OCN), collagen type I (COL-I), runt-related transcription factor 2 (Runx2), and alkaline phosphatase (ALP) transcripts were examined employing quantitative RT-PCR. Biomineralization of the cementoblasts was evaluated on day 8 via von Kossa staining. Results: Sepiolite decreased proliferation of the cementoblasts when compared to untreated control group. While there was no change for BSP mRNA expression for both time points, sepiolite up-regulated OCN, Runx2, COL-I and ALP mRNA expressions (p <0.01) on days 3 and 6 when compared to control. Sepiolite stimulated mineralized nodule formation of the cementoblasts when compared to mineralization media group (positive control). Conclusion: The findings of this study demonstrated that sepiolite enhances the functions of the cementoblasts involving new cementum formation which is critical for periodontal regeneration. Results suggested that sepiolite has potential as a graft material in dentistry and medicine.
Citation - WoS: 2
Citation - Scopus: 2
A Study on Optimum Tilt Angle of Pv Panels for Konya, Turkey
(Institute of Electrical and Electronics Engineers Inc., 2022) Arslan, Mustafa; Cunkas, Mehmet
In order to reduce foreign dependency on Turkey, domestic and renewable energy resources and investments are of great importance. In recent years, technological innovations and research and development activities have increased the interest in renewable energy sources, especially solar and wind, in meeting the increasing energy demand. In this respect, when the potential of Turkey's wind and solar energy resources is evaluated, Konya stands out compared to other provinces. The performance of a photovoltaic panel depends on the tilt angle and the azimuth angle. In this study, wind and solar potential among Turkey's renewable energy resources are briefly discussed and compared to other countries. The optimum panel tilt angle is calculated monthly, seasonally, and yearly for Konya province. A model was proposed based on the declination angle for finding the optimum tilt angle. © 2022 IEEE.
Citation - WoS: 2
Citation - Scopus: 2
Synthesis and Application of Colloidal Cds Quantum Dots as Interface Modification Material in Perovskite Solar Cells
(Scientific Technical Research Council Turkey-Tubitak, 2021) Yenel, Esma
In this study, colloidal CdS quantum dots were synthesized, structurally characterized, and their effect on performance of perovskite solar cells was observed by using them as interface modification agent between TiO2/perovskite. Colloidal CdS quantum dots were synthesized based on two-phase method and characterized by X-ray diffraction and Transmission Electron Microscopy techniques. The average particle size of CdS quantum dots have found to be around 5 nm. Oleic acid was used as capping agent during synthesis to lead solubility in organic solvents. Obtained quantum dots are coated on compact TiO2 layer for surface modification. A decrease was observed when oleic acid capped CdS quantum dots were used at interface, while significant improvement was observed when ligand exchange was carried out by pyridine before perovskite layer. Reference solar cells showed 11.6% efficiency, while pyridine capped CdS modified solar cells' efficiency was 13.2%. Besides the improvement in efficiency, reproducibility of solar cells also was increased by using pyridine capped CdS as interface material.
Citation - WoS: 1
Citation - Scopus: 1
Uridine as Additive in Antisolvent for Improving Performance and Reproducibility of Perovskite Solar Cells
(Springer, 2022) Yenel, Esma; Deveci, İlyas
Today, with their high efficiency of up to 25%, perovskite solar cells are the best alternative to silicon solar panels, which have relatively difficult manufacturing process, with the increasing trend toward clean energy. Despite their high efficiency, there are some issues such as reproducibility that must be solved. Additive engineering is most promising method for overcoming this problem. In this study, Uridine molecule, which is pyrimidine nucleoside and has important role in living organism, was investigated as additive in secondary butanol with different concentrations (1/10, 1/20, 1/50, 1/100, and 1/300 dilutions from saturated solution). Secondary butanol was employed in antisolvent washing step during device fabrication. Obtained results were compared with the results that of device referred as reference and fabricated without using Uridine. The results showed that the average efficiencies and reproducibility of device increase by Uridine doping. The highest efficiency increase was obtained for the device fabricated using solutions, including Uridine with 1/50 dilution. The Uridine molecule deposited between boundary layer and the perovskite grains promoted the charge transfer rate by means of passivating the traps formed during the fast crystal growth.

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