Teknik Bilimler Meslek Yüksekokulu Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/1629

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Now showing 1 - 9 of 9

Citation - WoS: 12
Citation - Scopus: 17
Acoustic-Driven Airflow Flame Extinguishing System Design and Analysis of Capabilities of Low Frequency in Different Fuels
(Springer, 2022) Taşpınar, Yavuz Selim; Köklü, Murat; Altın, Mustafa
Traditional fire extinguishing methods can harm people and nature. For this purpose, in this study, no harmful acoustic-driven airflow fire extinguishing system was developed and experiments were carried out to extinguish gasoline, kerosene, thinner (synthetic thinner) liquid fuels and liquid petroleum gas (LPG) flames. 17,442 extinguishing experiments were conducted in 5 different flame sizes, 54 different frequencies and 10 cm to 190 cm distance range. The data obtained were analyzed using the polynomial regression method. For liquid fuels, the frequencies of 10 Hz to 50 Hz at a distance of 10 cm to 100 cm, 10 Hz to 32 Hz at a distance of 100 cm to 150 cm, and 10 Hz to 28 Hz at a distance of 150 cm to 180 cm are effective extinguishing ranges. LPG fuel, 10 Hz to 45 Hz at a distance of 10 cm to 140 cm, frequencies of 15 Hz to 30 Hz at a distance of 140 cm to 180 cm are effective extinguishing ranges. In addition, caused by the compression of the woofers membrane inside the collimator and the injected airflow at frequency of 30 Hz reduced the 12 cm diameter metal plate from 86.2 degrees C to 18.8 degrees C in 5 min, and the metal plate left to cool down from 80 degrees C to 21.7 degrees C in 10 min at a distance of 100 cm. The average Mean Square Error value obtained as a result of polynomial regression analysis is 0.9544, and the Root Mean Square Error value is 1.2020.
Citation - WoS: 15
Citation - Scopus: 15
Developing a Deep Neural Network Model for Predicting Carrots Volume
(SPRINGER, 2021) Örnek, Mustafa Nevzat; Örnek, Humar Kahramanlı
In this paper, a deep learning approach to predict carrots volume according to the physical properties was designed. A total of 464 carrots were used for volume prediction. The used carrots were taken from Kasinhani, Konya. First, the data was produced. For this, the length, the diameters with 5 cm intervals, and the volume of each carrot were measured and recorded. The measurements were done using a steel ruler, a vernier caliper, and a glass graduated cylinder. Two deep learning methods: DFN and LSTM were developed to predict carrot volume. The developed systems were implemented with the Keras library for Python. Statistical measures such as Root Mean Squared Error, Mean Absolute Error, and R-2 were used to determine the predicting accuracy of the system. Both methods produced very close values. DFN and LSTM networks achieved 0.9765 and 0.9766 R-2, respectively. RMSE values were 0.0312 for both models. The results obtained showed that both DFN and LSTM are successful and applicable to this task.
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 Cutting Direction and Water Based Varnish Type on Sound Absorption Coefficient in Some Native Wood Species
(2024) Muslu, Mustafa Selmani
Noise which could be defined as disturbing sound, is becoming a major problem depending with developing technology. Controlling the noise helps raising the quality of life to higher levels. Although the intensity of the noise is not at a level that will affect human health, it should be reduced or eliminated, for better life standart. Due to the adverse effects of the noise level on health; the acoustic properties of living areas require serious consideration. Sound absorption coefficients of the materials used in the interior play an important role in providing sensory comfort depending on the volume. Natural and artificial wood are commonly used materials in interior design, especially in the construction of partition elements. In addition, wood is natural material and it has some important advantages and disadvantages. In this study the sound absorption coefficients of eastern beech and scotch pine trees, which are the most preferred materials in in-terior design, were investigated. For this pupose, these wood materials were cut superficially and radially according to the intersection directions, then the sample surfaces were varnished with one and two component water-based varnishes that do not contain solvent-based resin. The sound absorption coefficients of the ob-tained samples were determined by the impedance tube method and the results were compared statistically. It has been investigated that the obtained results could be evaluated statistically within the frequency values, besides, different results could be obtained according to the characteristics of natural wood materials, the direc-tion of intersection and water-based varnish types. According to the findings obtained as a result of the study, it has been suggested that if natural wood material is used indoors, the superficial cross-section of East beech wood should be used according to the direction of intersection, and a two-component varnish should be used according to the varnish type.
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.
Citation - WoS: 9
Citation - Scopus: 11
Enhanced Control Method for Voltage Regulation of Dstatcom Based Seig
(Elsevier, 2022) Özer, Ali Sait; Sevilmiş, Fehmi; Karaca, Hulusi; Arabacı, Hayri
Self-excited induction generator (SEIG)-based wind energy conversion systems (WECS) are very popular for feeding standalone loads in remote areas where there is no grid. SEIG needs adjustable reactive power to regulate terminal voltage and frequency. Usually, a combination of a distributed static compensator (DSTATCOM) and a fixed capacitor bank is used to meet this reactive power demand. DSTATCOM is the most suitable option for power quality compensation. The performance of DSTATCOM depends on its control algorithm that generates the proper switching signals for voltage source inverter (VSI). Many control algorithms have been proposed for DSTATCOM in the literature. Among them, the most frequently used algorithms are synchronous reference frame (SRF), instantaneous reactive power (IRP), and current synchronous detection (CSD) algorithms. An effective control algorithm must accurately estimate the amplitude of the terminal voltage without being affected by harmonics, DC-offset, and frequency variation. For this purpose, an enhanced phase locked loop (EPLL)-based CSD control algorithm is proposed to estimate the amplitudes of individual phase voltages, and to filter SEIG voltages in case of harmonics, DC offset, and frequency variation. The proposed algorithm has been tested under linear and nonlinear load conditions. The obtained results clearly demonstrate the effectiveness of the proposed EPLL-based CSD control algorithm. (C) 2022 The Author(s). Published by Elsevier Ltd.
Citation - WoS: 21
Citation - Scopus: 22
Hplc-Dad Characterization of Phenolic Profile and in Vitro Antioxidant, Anticholinesterase, and Antidiabetic Activities of Five Mushroom Species From Turkey
(Springer Heidelberg, 2021) Çayan, Fatih; Tel-Çayan, Gülşen; Deveci, Ebru; Duru, Mehmet Emin
In this study, Daedalea quercina (L.) Pers., Hydnum repandum L., Inonotus radiatus (Sowerby) P. Karst., Omphalotus olearius (DC.) Singer, and Schizophyllum commune Fr. hexane and methanol extracts were subjected to the spectrophotometric assays for antioxidant and enzyme inhibitory activities, which are linked with human diseases that are very prevalent in recent years. Additionally, phenolic compounds of the mushrooms were quantified by HPLC-DAD. The best antioxidant activity was found in H. repandum methanol extract (IC50: 12.04 +/- 0.24 mu g/mL) in the beta -carotene-linoleic assay; I. radiatus methanol extract in DPPH center dot (81.22 +/- 0.50%), ABTS(center dot+) (IC50: 73.47 +/- 0.18 mu g/mL), and CUPRAC (A(0.50): 88.21 +/- 0.02 mu g/mL) assays; S. commune hexane extract (53.36 +/- 0.89%) in the metal chelating assay. O. olearius hexane extract was found as the best inhibitor against AChE (71.58 +/- 0.28%) and BChE (67.30 +/- 0.15%). When I. radiatus methanol (95.88 +/- 0.74%) and H. repandum hexane (95.75 +/- 0.16%) extracts showed close alpha -amylase inhibitory activity to acarbose (96.68 +/- 0.08%), D. quercina methanol extract (70.79 +/- 0.34%) had higher alpha -glucosidase inhibitory activity than acarbose (67.01 +/- 2.28%). Among 16 phenolic compounds analyzed, gallic acid (0.02 +/- 0.01-0.23 +/- 0.01 mu g/g) was detected in all studied mushrooms. This study provides that investigated mushrooms can be used for further research, which can lead to the development of new natural remedies to alleviate complications related to oxidative stress, diabetes, and neurological diseases.
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: 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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