Mühendislik Fakültesi, Enerji Sistemleri Mühendisliği Bölümü, Makale Koleksiyonu

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https://hdl.handle.net/11492/872

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Parameter estimation and validation of cascaded DC-DC boost converters for renewable energy systems using the IGWO optimization algorithm
(Elsevıer Science Sa, 2025) Çeltik, Seyit Alperen; Kül, Seda; Balcı, Selami; Dik, Abdullah
The voltage amplitude generated by renewable energy sources is often unstable, necessitating the use of power electronic circuits for effective grid integration. Among these, DC-DC converters play a critical role in maintaining a constant DC link voltage, typically 400 V or 800 V, at the input of inverter circuits that supply power to the load or the grid. The study focuses on the voltage gain behavior of a high-gain dual cascaded DC-DC boost converter designed for PV (photovoltaic) power systems. Using ANSYS Electronics software with its parametric solver, a comprehensive dataset was generated based on key parameters such as input voltage, power switch duty ratio, and switching frequency. The Improved Grey Wolf Optimizer (IGWO) algorithm was employed to estimate mathematical models for this dataset using linear and quadratic equations. The accuracy of the proposed models was validated across six test scenarios, demonstrating superior performance compared to traditional optimization algorithms, including Harmony Search (HS), Particle Swarm Optimization (PSO), Differential Evolution (DE), and the standard Grey Wolf Optimizer (GWO). Experimental validations yielded output voltages of 23.5 V and 36.1 V for input voltages of 4.8 V and 6.2 V, respectively, closely aligning with simulation results of 23.113 V and 36.447 V. The findings, supported by detailed simulations and graphical analyses, highlight the IGWO algorithm's precision and reliability in predicting converter output voltages under variable input conditions. This work advances renewable energy systems integration by enhancing the modeling and performance of cascaded DC-DC boost converters.
Determination of solar reflection coefficients (albedo) from satellite images using google earth engine platform
(2024) Yıldız, Mehmet Alper; Karabörk, Hakan; Rüşen, Selmin Ener
In many models calculating solar radiation, a combination of physical measurements and mathematical models is used to achieve results close to reality. In these calculations, the slope values and shading effects in the region being analyzed are often disregarded. Mathematical models such as ArcGIS's Area Solar Radiation (ASR) can calculate shading effects on three-dimensional surfaces. When solar radiation models are computed in three dimensions, accounting for solar rays reflected from the ground, in addition to atmospheric reflections, will increase accuracy. This study aimed to determine the surface reflectance coefficients that should be added in three-dimensional radiation models. In literature, general assumptions exist for surface reflectance coefficients, which represent very broad average values. However, this study aimed to establish precise albedo values for all land classes and surfaces. An area of approximately 1600 km² located in the mountainous region south of Karaman was chosen as the test area. This area was chosen in Karaman province because, as is known, this region has high solar energy potential. Sentinel 2A satellite images with a spatial resolution of 10 meters were used for both summer and winter seasons through the Google Earth Engine (GEE) platform. For the summer and winter applications, the albedo value for snowy surfaces was calculated as 0.86, while for light-colored buildings, it was 0.36 for summer and 0.28 for winter. Although examples were provided for some land classes, the study ultimately determined albedo values for all land surfaces without differentiation between classes.
Farklı lokasyonlarda yetiştirilen şeker pancarı bitkisinin (Beta vulgaris L.) bazı morfolojik ve teknolojik karakterlerinin hasat zamanlarına göre değişiminin incelenmesi
(Karamanoğlu Mehmetbey Üniversitesi, 2023) Cesur, Cüneyt
Bu araştırma 2014–2015 yıllarında, Orta Anadolu bölgesinde, şeker pancarı bitkisinin verim ve verim unsurları üzerine genotip–çevre ilişkilerinin etkisinin incelenmesi amacıyla yapılmıştır. Araştırmada bölgeye uyumlu Turbata çeşidi kullanılmıştır. Nisan ayının ilk günlerinde yapılan ekimlerde lokasyonlar (Şefaatli ve Sarıkaya) ana parselde, hasat zamanları (15 Eylül, 1 Ekim, 15 Ekim ve 1 Kasım) ise alt parsellerde oluşturulmuştur. Farklı lokasyon ve hasat zamanlarının kök (gövde) boyu, kök (gövde) ağırlığı, kök (gövde) çapı, biyokütle ağırlığı, şeker oranı, kuru madde, usare safiyeti, α amino azot (N), melas oranı, yaprak ağırlığı, kül oranı, pancar verimi özelliklerine etkisi incelenmiştir. Elde edilen neticelere göre lokasyonlara göre şefaatli lokasyonun kök (gövde) ağırlığı (751.7 kg/da), kök (gövde) çapı (11.8 cm) biyokütle ağırlığı (902.8 kg/da), α amino N (0.050), yaprak ağırlığı (287.29 kg/da) ve pancar verimi (644.3 kg/da) özellikleri daha yüksek değerler oluştururken, Sarıkaya lokasyonunda ise kök (gövde) yüksekliği (18.3 cm), şeker oranı (16.5%), kül oranı (3.134%), usare safiyeti (89.5%), şeker oranı ve kuru madde (19.98%) özellikleri daha yüksek değerler oluşturmuştur. Temel bileşen analizine göre PC1 %50.03 olarak gerçekleşirken, PC2 %17.11 olarak gerçekleşmiştir.
Electrochemical and optical properties of poly(4-(4-(1H-pyrrol-1-yl)phenyl)-4H-dithieno[3,2-b:2',3'-d]pyrrole
(Springer, 2024) Çarbaş, Buket Bezgin; Ergin, Nurseli Mislina; Yıldız, Hüseyin Bekir; Kıvrak, Arif
A novel dithieno[3,2-b:2',3'-d]pyrrole (DTP) derivative, namely, 4-(4-(1H-pyrrol-1-yl)phenyl)-4H-dithieno[3,2-b:2',3'-d]pyrrole (DTP-Ph-Pyr) was synthesized, and its corresponding polymer (P(DTP-Ph-Pyr)) was successfully obtained via electrochemical polymerization. Electrochemical and optical properties of this novel polymer were discussed in detail. It was found that the polymer film also exhibited a reversible electrochromic behavior (orange color in the neutral state and blue color in the oxidized state) with a high optical contrast (52.5% at 950 nm) and coloration efficiency (123 cm2/C at 950 nm). Moreover, the electrochemical and optical properties of the polymer were compared with both its electrochromic P(DTP) analogues and its sister polymer structure, poly(1-(4-(1H-pyrrol-1-yl)phenyl)-2,5-di(thiophen-2-yl)-1H-pyrrole) (P(SNS-Ph-Pyr)), possessing same subunit. Graphical abstract: [Figure not available: see fulltext.
Estimation of PEMFC design parameters with social learning-based optimization
(Springer Science and Business Media Deutschland GmbH, 2024) Çeltek, Seyit Alperen
Parameter estimation of proton exchange membrane fuel cell (PEMFC) design is crucial in developing and optimizing PEMFC technology. This study proposes a social learning-based swarm optimization technique to solve the PEMFC design problem. Social learning is based on particles learning from each other and sharing information in a swarm. This allows better solutions found by one particle in the swarm to be used by others, allowing them to arrive at a globally better solution in less iteration. The proposed approach uses the social learning particle swarm optimization (SL-PSO) algorithm to minimize the sum of squared errors (SSE) between the calculated and experimental voltage for the PEMFC parameter extraction problem. The study was carried out on two types of PEMFC (500 W Horizon and BCS 500 W) and compared with heuristic methods commonly used in the literature. This study is the first time in the literature that SL-PSO has been used to optimize PEMFC design parameters. The results show that the SL-PSO-based approach achieves SSE values of 3.8 × 10 - 2 and 4.903 × 10 - 2 for BCS 500 W and 500 W Horizon, respectively. The output reveals that the SL-PSO-based method is an effective optimization tool in PEMFC design by achieving better SSE value in minimum iteration than other comparative algorithms. The proposed approach is expected to be more helpful in making highly efficient fuel cell-based energy systems because of promising results.
Fatty Acid Composition of Seed Oil from Cocklebur (Xantium Strumarium Subsp. Strumarium) Grown in Turkey
(Sivas Cumhuriyet Üniversitesi, 2022) Cesur, Cüneyt; Coşge Şenkal, Belgin; Uskutoğlu, Tansu
Vegetable oils are not only used for human consumption but also used for industrial purposes (soaps, biodiesel, painting, cosmetics, etc.). One of the most important criteria in determining the usage areas of vegetable oils is the fatty acid composition it contains. Turkey supplies its edible oil needs with both seed and vegetable oil imports. To meet this vegetable oil need of Turkey, vegetable oils obtained from different plants are of great importance. This study, it was aimed to determine the oil content, fatty acid composition, and some properties of cocklebur (Xantium strumarium subsp. strumarium) seeds collected from the natural area. 100 fruit weight (g), seed weight (g), and hull ratio (%) were determined as 32.23±2.66, 7.17±0.99, and 77.70±2.84, respectively. Cocklebur seeds contain 24.19% seed oil. Its oil is rich in linoleic (%76.97) and oleic (%11.91) acids.
Construction of novel cyanobacteria-based biological photovoltaic solar cells: Hydrogen and photocurrent generated via both photosynthesis and respiratory system
(Elsevier B.V., 2023) Çarbaş, Buket Bezgin; Güler, Menşure; Yücel, Kamile; Yıldız, Hüseyin Bekir
Biological photovoltaic (BPV) cells use biological organisms in order to produce clean electrical power by capturing solar energy. In this study, a cyanobacteria based BPV cell was constructed and it generated H2 gas and photocurrent via photosynthesis and respiratory system. This kind of BPV cell was constructed in which the cathode and photoanode are gold electrodes coated with different conjugated polymers and these polymers are combined to Pt or Au nanoparticles with oligoaniline bonds. Unlike the cathode electrode, a kind of cyanobacteria (Leptolyngbia sp.) was used in the design of photoanode and bounded to Au NPs with oligoaniline bonds. For the configuration of cathode in BPV cell, a gold electrode was first coated with a dithienylpyrrole-based conductive polymer with an amine open-ended aniline functional group. This conductive polymer was then attached to mercapto-aniline functionalized Pt nanoparticles with oligoaniline bonds. In the case of photoanode in BPV cell, this time, a dithienopyrrole-based conductive polymer with an aniline subunit was coated on another Au electrode surface via electrochemical polymerization. This polymer provides to connect oligoaniline modified Au nanoparticles with coating cyanobacteria. Some control and optimization experiments for photoanode of the system were done in order to understand photosynthesis formation and get efficient photocurrent from BPV cell. The system was illuminated under visible light and a constant potential and then the decomposition of water in BPV solar cell system was observed via photosynthesis by cyanobacteria with the formation of H2 and O2 gases besides photocurrent generation. Another photocurrent generation via respiratory system of cyanaobacteria was also investigated in the medium of glucose after diuron (PS II inhibitor an inhibitor) was added into medium. By using two different properties (photosynthesis and respiratory system) of cyanobacteria, BPV solar system generates high amount of photocurrent and hydrogen.
Effect of Au nanoparticle doped ZnO buffer layer on efficiency in organic solar cells
(Elsevier B.V., 2023) Yurtdaş, Semih; Karaman, Mustafa; Tozlu, Cem
Although organic solar cells have great potential, there is a need to increase their efficiency values. In this study, ITO/ZnO/P3HT:PCBM/MoO3/Ag structure was used and it was aimed to increase the efficiency by adding different percentages of Au nanoparticles (nps) into the ZnO electron transport layer. According to the best results, adding 10% (V/V) Au into ZnO increased the power conversion efficiency from 2.94% to 3.48%. Thus, efficiency increase of nearly 20% was achieved. The main reason for the increase in efficiency is the increase in current density by utilizing the plasmonic effects of Au nps. While the current density was 8.14 mA/cm2 in the device without Au nps, the 10% Au doping increased to 8.58 mA/cm2 in the device.
A comprehensive overview of carbazole-EDOT based electrochromic copolymers: A new candidate for carbazole-EDOT based electrochromic copolymer
(Elsevier Ltd., 2023) Çarbaş, Buket Bezgin; Özbakır, Sinan; Kaya, Yasemin
In recent years, there has been an increase in the demand for the synthesis of carbazole-EDOT based electrochromic copolymers since this combination of structures facilitates the obtaining of a free standing film on the working electrode and improves the electrochromic properties of the polycarbazole (PC) polymer. In this study, carbazole-EDOT based copolymers with electrochromic properties in the literature were classified into three groups and the effect of changing the carbazole/EDOT order on the polymer chain on the electrochromic properties of the obtained copolymer was tried to be revealed. Moreover, as an example, a new candidate for carbazole-EDOT based electrochromic random copolymer was introduced. Carbazole and EDOT monomers were copolymerized electrochemically in nonacidic medium for a clear and basic comparison. The electrochemical and spectroelectrochemical studies show that the corresponding copolymer, poly(C-co-EDOT), contains freestanding property on working electrode and shows multielectrochromic property. The copolymer gave a λmax value at about 545 nm with a band gap of 1.74 eV. As expected, EDOT monomer inserting to the polycarbazole chain improves electrochemical and optical properties of homopolymer PC. The electrochromic performance of new copolymer was also compared with its homopolymers components (polymer of carbazole (C) and EDOT) and carbazole-EDOT based electrochromic random copolymers in literature. The experiments showed that poly(C-co-EDOT) was an electroactive material with higher coloration efficiency (CE) (258 cm2/C at 900 nm) than that of PC and carbazole-EDOT based random copolymers in literature. DFT theoretical and experimental calculations were also achieved in order to find HOMO and LUMO energy levels besides band gap and compared with each other. No such a theoretical calculation related electrochromic PC polymer and that kind of random electrochromic copolymer has ever been encountered in the studies carried out so far. Since this research is a baseline study for the valuable design of carbazole-EDOT based electrochromic copolymer, it is thought to shed light on the scientists who will work on this subject in the future.
Vapor deposition of poly(hexafluorobutyl acrylate) nanocoating for encapsulation of organic solar cells
(Elsevier B.V., 2023) Yurtdaş, Semih; Tozlu, Cem; Karaman, Mustafa
The biggest problem of organic photovoltaics is their quickly deterioration in atmospheric conditions. O2 and moisture in the air affect device performance negatively. In this study, at first, it is determined which electrical parameter used in the device efficiency calculation is affected by atmospheric conditions. For this context, produced devices were kept in room conditions, desiccator, and glovebox, respectively. Stability tests were performed for 8 weeks. According to the results, predominantly, current density (Jsc) is affected by O2, open circuit voltage (Voc) is affected by moisture while fill factor (FF) is affected by both O2 and moisture. Normalized efficiency (η) values are decreased, the devices kept in room conditions, desiccator, and glovebox, 90 %, 60 %, and 20 %, respectively. In the second part, devices were encapsulated with poly(Hexafluorobutylacrylate) (PHFBA) using batch initiated chemical vapor deposition (iCVD) technique at varying thicknesses. FTIR and XPS studies revealed successful PHFBA polymerization coatings. Efficiency losses for encapsulated devices was measured as between 30 and 35 %. When the non-encapsulated and encapsulated devices kept under room conditions were compared, the reductions in efficiency were found to be 90 % versus 30 %. According to the results, PHFBA has good barrier properties against O2 and moisture.
Enhanced photocatalytic hydrogen evolution and antibacterial activities of ternary chevrel phases
(John Wiley and Sons Inc, 2023) Genç Acar, Eminegül; Kuru, Talha; Sarılmaz, Adem; Süleyman Özel, Sultan; Karanfil Kaçmaz, Gamze; Özel, Faruk
Chevrel phases consisted of abundant materials, are of great interest in a variety of energy conversion and storage technologies because of unique structural and electronic features. Herein, crystalline Mn2Mo6S8, Fe2Mo6S8 and Cu2Mo6S8 Chevrel phases with cubic shapes and homogeneous atomic distribution have been synthesized by solid state method and characterized by advanced analytical techniques. These Chevrel phase catalysts have been investigated for the photocatalytic hydrogen evolution in eosin-Y and triethanolamine media as sensitizer and sacrificial agent, respectively, under visible light irradiation. Mn2Mo6S8 showed the highest photocatalytic hydrogen evolution activity, which is 2.5-fold and 3-fold greater than that of Fe2Mo6S8 and Cu2Mo6S8, respectively. The photocatalytic activity differences of Chevrel phase catalysts can be explained by atomic properties of Mn, Fe and Cu metals. Moreover, the antibacterial efficiencies of Mn2Mo6S8, Fe2Mo6S8 and Cu2Mo6S8 have been also examined on Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, as model microorganisms. Accordingly, Mn2Mo6S8 exhibited physical membrane damages such as dents, wrinkled cells and cell elongation and has the most superior antibacterial activity under NIR irradiation.
Optical, electrochemical and DFT studies of donor-acceptor typed indole derivatives
(Univ Ljubljana, 2022) Çarbaş, Buket Bezgin; Noori, Hussein Ali; Kavak, Emrah; Kaya, Yasemin; Kıvrak, Arif
The donor-acceptor type indole chromophore motif presents an interesting molecular architecture to the scientific world, unfortunately, as in every special and beautiful formation needed; their synthesis represents a synthesis challenge. In the current search, new donor-acceptor typed indole derivatives, 1-methyl-phenyl-3-aldehyde indole (HAN-1), 2-(((1-methyl-2-phenyl-1H-indol-3-yl)methylene)malononitrile ( HAN-2), 1-ethyl-2-phenyl-3-aldehyde indole (HAN-3), 2-((1-ethyl-2-phenyl-1H-indol-3-yl)methylene)malononitrile (HAN-4) were successfully synthesized and the results supported with FTIR and NMR spectra analysis. All the molecules undergo excited state intramolecular electron transfer with unique charge transfer reaction. Their electrochemical and optical properties were investigated in relation to the acceptor effect of functional groups on the indole units in the conjugated structure. Density functional theory (DFT) calculations exhibited that higher electron withdrawing ability strength resulted in decreased HOMO-LUMU gaps of the molecules. Futhermore, donor acceptor typed indole derivatives undergo irreversibly one electron oxidation in the medium of 0.1 M TBAPF(6)/ACN solution with a similar onset oxidation potentials. Both experimental and theoretical studies showed that the electron withdrawing ability of the molecules affect more LUMO energy level of the molecules. Moreover, they suggest that donor acceptor indole molecules herein are potential candidates for fabrication of dye synthesized solar cells.
A sample study for determining energy consumption values in public buildings: Central anatolia region
(Springer, 2022) Rüşen, Selmin Ener; Rüşen, Aydın
Today, it is known that the role of energy efficiency in the development of countries is very crucial. When our country is viewed from this point of view, it is seen that energy efficiency studies aimed to reduce the energy density value have become more and more important and policies are implemented in this direction. Therefore, in this study, an exemplary study was conducted to determine the saving potential of the energy used in Turkey. In order to find energy usage in the public buildings in KOP Region, which includes 7 cities in Central Anatolia Region (Karaman, Aksaray, Kirikkale, Kirsehir, Yozgat, Nevsehir, and Nigde), the amount of energy consumed per person and per square meter was determined. The calculation was made based on the energy consumption values obtained from public buildings (administrative buildings, schools, dormitories, sports facilities, prisons, and universities) in 7 cities in the KOP Region between 2014-2018 years. According to the obtained data, it is observed that energy consumption is high in mass living areas of public buildings. The results are encouraging for the future works to use energy efficiency in public buildings.
A new electrochromic copolymer composed of 4,7-di(thiophen-2-yl)benzo[c] [1,2,5] thiadiazole and 3,4-ethylenedioxythiophene
(Scientific Technical Research Council Turkey-Tubitak, 2022) Çelik, Kübra; Kıvrak, Arif; Çarbaş, Buket Bezgin
A new electrochromic copolymer based on 4,7-di(thiophen-2-yl)benzo[c] [1,2,5]thiadiazole and 3,4-ethylenedioxythiophene was successfully obtained via the electrochemical polymerization method in the medium of electrolyte solution, which consists of 0.1 M tetrabutylammonium hexafluorophosphate and dichloromethane. In order to compare the electrochemical and chemical properties of the copolymer, the benzothiodiazole derivative and 3,4-ethylenedioxythiophene (EDOT) monomers, which are parts of the copolymer, are electrochemically polymerized, separately in the same environment and concentration with the copolymer. Poly(4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole) (P(TBT)) and poly(3,4-ethylenedioxythiophene) (PEDOT) polymers were obtained. Before starting the electrochemical synthesis, the initial oxidation potentials of the monomers that form the copolymer were compared via the cyclic voltammeter method in this solvent electrolyte medium. Then, electrochemical and spectroelectrochemical characterizations of electrochemically synthesized polymers and copolymers were performed. New copolymer shows metallic blue and centaury blue in its neutral and oxidized states, respectively with a low band gap of 1.32 eV. Moreover, the copolymer has a 59% optical contrast and high coloration efficiency (324 cm2C-1) at 585 nm with a switching time of 2.2 s.
Electrochromic properties of a polydithienylpyrrole derivative with N-phenyl pyrrole subunit
(Elsevier, 2022) Çarbaş, Buket Bezgin; Ergin, Nurseli Mislina; Yıldız, Hüseyin Bekir; Kıvrak, Arif; Demet, Atıf Emre
In this report, a new N-phenyl typed 2,5-dithienyl pyrrole compound bearing pyrrole unit was successfully synthesized and its conjugated homopolymer, poly(1-(4-(1H-pyrrol-1-yl)phenyl)-2,5-di(thiophen-2-yl)-1H-pyrrole) (P(SNS-Ph-Pyr)), was obtained in the medium of 0.1 M TBAPF6/DCM via electroanalytical methods. Cyclic voltammetry and FTIR studies proved that monomer SNS-Ph-Pyr was synthesized and polymerized electrochemically and its corresponding polymer film, P(SNS-Ph-Pyr)) has a well reversible redox peaks at about 0.70/0.50 V vs. Ag/AgCl reference electrode in monomer free solution with a long term reversible redox behavior. The in situ UV–visible spectroelectrochemical studies of polymer film exhibited that electrochromic P(SNS-Ph-Pyr)) film had a color transition between yellow (at reduced state (0.0 V)) to grayish blue (at oxidized state (1.0 V)) with a intermediate color (green at 0.70 V). Moreover, electrochromic switching studies displayed that polymer film (coated with a thickness of 100 mC/cm2) had average optical contrast values (15.6% (383 nm), 19.5% (650 nm) and 41.7% (900 nm) but high coloration efficiency values (220 cm2/C (383 nm), 264 cm2/C (650 nm) and 384 cm2/C (900 nm). © 2022 Elsevier B.V.
FEM-based modeling and optimization of dry-type transformers with metaheuristic algorithms
(Strojarski Facultet, 2022) Kül, Seda; Tezcan, Süleyman Sungur; Duysak, Hüseyin; Çeltek, Seyit Alperen
Transformer optimization is a programming problem with an objective function for calculating the characteristics of a transformer in detail according to user requirements. Especially in recent years, efficient and optimum design of the transformer has become increasingly important. This study presents a comparative analysis of the application of metaheuristic optimization algorithms in transformer design for maximum efficiency of a three-phase dry-type transformer. In addition, transformer modeling was done using FEM analysis, and its magnetic characteristics were shown. The main contribution of this paper is to optimize the determined basic design parameters with optimization methods that have not been used in transformer optimization before and to maximize efficiency by reducing losses. During this process, using the loss constants of the materials in the basic loss equation for core loss, this process was tried to be carried out without any change in the method in applications to be made with different materials. This situation also strengthens the accuracy of the applied method. Crow Search (CSA), Moth-Flame Optimization (MFO), Vortex Optimization (VOA), Particle Swarm Optimization (PSO), and Social Learning-Particle Swarm Optimization (SL-PSO) algorithms were used in the study. The loss values were obtained by performing loaded and unloaded FEM analysis with the ANSYS/Maxwell program. As a result, the best result was obtained with SL-PSO as max 99,05%.
A statistical optimization attempt by applying the Taguchi technique for the optimum transesterification process parameters in the production of biodiesel from Papaver somniferum L. seed oil
(Elsevier Ltd., 2022) Yeşilyurt, Murat Kadir; Cesur, Cüneyt
This work has been accomplished for synthesizing biodiesel from crude oil extracted from Papaver somniferum L. seeds. The oil content of the seeds was detected to be at 43.51 ± 1.58 % which is higher than most of the feedstock used in biodiesel production. The obtained oil was exposed to the transesterification process under demanded reaction conditions as an L9 (9–runs) orthogonal attempt guessed by the Taguchi method. In conclusion, the highest yield of the produced biodiesel was found at the following optimized reaction conditions: molar ratio for methanol to oil of 9:1, NaOH concentration of 0.75 wt%, reaction temperature of 60 °C, and reaction time of 60 min. The exploration of the prominent reaction factors was acquired thanks to the Taguchi technique and the substantial parameters were found to be as follows: catalyst concentration, molar ratio for methanol to oil, reaction temperature, and reaction time with the contribution factors of 47.18 %, 30.04 %, 16.87 %, and 5.91 %, respectively. The statistical analysis carried out based on the ANOVA demonstrated that the monitored yield (88.97 %) were in good consonance with the estimated yield (89.93 %). In addition, the physicochemical characteristics of produced biodiesel was within the limits given in the global biodiesel standards. It can be concluded that Papaver somniferum L. seed oil can be recommended as a novel and important feedstock for biodiesel production in the close future studies as well as industrial applications when the obstructions will remove for the harvesting of this plant.
Synthesis and characterization of an electrochromic copolymer based on 9, 10-di (furan-2-yl)anthracene and 3,4-ethylenedioxythiophene
(TÜBİTAK, 2022) Kalçık, Ali; Kıvrak, Arif; Çarbaş, Buket Bezgin
In this study, a new copolymer, which is a combination of two chemical structure (9,10-di(furan-2-yl)anthracene and 3,4-ethylenedioxythiophene was synthesized via electrochemical synthesis methods in the electrolyte medium of 0.1 M TBAPF6/ ACN solution. PEDOT homopolymer was also electrosynthesized for comparator experiments of the polymer formations in the same medium. The characterizations of polymers were achieved with general optical and electrochemical characterization techniques. The corresponding electrochromic copolymer shows blue and lilac color in its neutral and oxidized states, respectively. The copolymer has an optical band gap of 1.65 eV and 24% optical contrast at 500 nm with a high coloration efficiency (170 cm2 /C) and a fast switching time (1.0 s). © 2022 TUBITAK. All rights reserved.
Chasing the black electrochromism: A new electrochromic copolymer based on 4,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)benzo[c][1,2,5]thiadiazole and ProDOT
(Elsevier, 2022) Cansu Ergun, Emine Gül; Çarbaş, Buket Bezgin
Absorbing all the visible light, in other words, neutral state black electrochromics has a great importance for certain applications such as smart windows, electronic papers, car rear views or displays. In this study, it was focused on a combination of monomers that can absorb entire the visible region. Poly(4,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)benzo[c][1,2,5]thiadiazole) (PEDAD) is a neutral state green polymer and has a dual absorption band before and after 500 nm, corresponding red and blue regions of the visible spectrum. On the other hand, polymer of dihexyl-3,4-propylenedioxythiphene (PProDOT) has an 400–700 nm optical absorption band with having a maximum at 584 nm. In the light of this information, a new copolymer, consisting of 4,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)benzo[c][1,2,5]thiadiazole and ProDOT, was synthesized via electrochemical techniques, to trap the entire visible region. 1:1 eq. of monomer feed was used and a neutral state very-dark copolymer was obtained. The copolymer showed enhanced optical contrast coming from PProDOT, (of having 44% transmittance) and lower band gap coming from PEDAD (of having 1.32 eV). In the oxidized state, the copolymer exhibited transmissive blue, coming from both homopolymers. © 2022 Elsevier Ltd.
A novel adaptive traffic signal control based on cloud/fog/edge computing
(Springer, 2022) Çeltek, Seyit Alperen; Durdu, Akif
This paper proposes the Internet of Things-based real-time adaptive traffic signal control strategy. The proposed model consists of three-layer; edge computing layer, fog computing layer, and cloud computing layer. The edge computing layer provides real-time and local optimization. The middle layer, which is the fog computing layer, performs a real-time and global optimization process. The cloud computing layer, which is the top layer, acts as a control center and optimizes the parameters of the fog layer and the edge layer. The proposed strategy uses the Deep Q-Learning algorithm for the optimization process in all three layers. This study employs the SUMO traffic simulator for performance evaluation. These results are compared with the results of adaptive traffic control methods. The output of this study shows that the proposed model can reduce waiting times and travel times while increasing travel speed.

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