Yazarlar

  • ArticleYalnız künye2019
    The design and experimentation of the new cascaded DC-DC boost converter for renewable energy

    Can, Erol

    After renewable energy generated, a direct current value is converted to a direct current value at another level for a power electronics and power system application that is often considered. In this article, the design and application of a new generation multi-time cascaded DC-DC converter are discussed. The dc-to-dc converter is three-levels, and the switches for each step have a working time and a non-working time. Mathematical models are established depending on the relationship between current and voltage according to the operating and non-operating states of the switches at each stage. After these mathematical models are creating, the new generation multi-timed DC-DC converter is run in Matlab Simulink and simulation results are validated in experimentation. The output voltage and inductor current are observed with a scope. Then, the results from the proposed converter are compared with the results of the traditional converters. The results show the effectiveness of the proposed dc-dc converter.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    RDL Kalıcı Kaydıİncele
  • ArticleAçık Erişim2019
    Comparison of different regression models to estimate fault location on hybrid power systems

    Ekici, Sami; Unal, Fatih; Ozleyen, Umit

    Various pattern recognition methods have been suggested for estimating high-voltage alternating current transmission line fault location. However, insufficient studies have been conducted on the transmission lines connected to hybrid power generation systems such as wind and solar plants. In this study, the performance of different regression methods was investigated on a hybrid power system. Different faults with random distances on the transmission line were simulated and a fault database created by recording the current and voltage signals of these faults. After normalising this data in the preprocessing phase, it was passed to the digital signal processing stage. By repeating the experiments, 497 different faults were created. Fault types, fault resistances, and fault inception angles were changed randomly in order to obtain similar fault occurrence conditions as in real life by writing a Matlab code. In order to obtain distinctive features, the discrete wavelet transform was used. For training and validation of the dataset, Matlab Regression Learner App (RLA) was employed and the obtained results compared to select the best model. After significant fault simulation, Matern 5/2, a type of Gaussian progress regression model, showed more promising results compared to other RLA models.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    RDL Kalıcı Kaydıİncele
  • ArticleYalnız künye2019
    The use of α-MnOOH nanosheets as battery-type electrode for supercapacitor applications

    Yesilbag, Yasar Ozkan; Tuzluca, Fatma Nur; Ertugrul, Mehmet

    This study investigated MnOOH nanosheets, which were synthesized at different manganese molarities on 3D-nickel foam by hydrothermal synthesis, for use as battery-type electrodes. The crystal structures and morphologies of the MnOOH nanosheets were determined by using X-ray diffraction, field emission scanning electron microscopy, energy dispersion X-ray spectroscopy, Raman Spectroscopy and X-ray photoelectron spectroscopy. Cyclic voltammetry, galvanostatic charge discharge and electrochemical impedance spectroscopy analysis of the MnOOH nanosheets were performed in 1 M of a KOH aqueous electrolyte solution. The specific capacity values obtained from GCD measurements taken at a current density of 0.5 A g-1 from samples called Mn-0.2, Mn-0.5, Mn-1 and Mn-2-according to their manganese molarities-were 230, 557, 766 and 493 C g-1, respectively. Furthermore, the Mn-1 sample, which had the highest specific capacitance value, showed excellent cycle stability by retaining 79% of the initial specific capacity after 10000 charge-discharge cycles.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    RDL Kalıcı Kaydıİncele
  • Conference ObjectYalnız künye2019
    Two Dimensional Ti3C2Tx MXene Electrode For Supercapacitor Application

    Tuzluca, Fatma Nur; Yesilbag, Yasar Ozkan; Shafiee, Farah Nabilah; Hamidon, Mohd Nizar; Ertugrul, Mehmet

    Two-dimensional materials are one of the most studied materials for many applications in recent years. Among the two-dimensional (2D) metal carbide, MXene is seen as one of the most promising materials for energy storage systems. Among the MXene family, Ti3C2Tx, the lightest material, is one of the electrode materials due to its unique electrochemical performance. In this study, Ti3C2Tx MXene structure was obtained by removing Al layer from Ti3AlC2 MAX structure by selective etching. Exceptional electrochemical performance and high electronic conductivity of Ti3C2Tx was obtained and surface and morphological analyzes were performed with FESEM, EDS, XRD. FESEM has demonstrated that synthesized MXene is a layered solid structure. In addition, synthesized MXene was tested for electrochemical behavior against electrochemical energy storage applications using techniques such as cyclic voltammetry (CV), galvanostatic charge discharge (GCD), and electrochemical impedance spectroscopy (EIS). Characterization and electrochemical tests have shown promising performance in electrochemical charge storage applications.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    RDL Kalıcı Kaydıİncele
  • ArticleYalnız künye2019
    Synthesis of TiO 2 nanotube/ZnO nanorod hybrid nanocomposite photoanodes for dye-sensitized solar cells

    Çırak, Burcu Bozkurt; Demir, Zeynep; Eden, Çiğdem; Erdoğan, Yaşar; Caglar, Bulent; Karadeniz, Sibel Morkoç; Kılınç, Tuba; Ekinci, Ali Ercan; Çırak, Çağrı

    TiO 2 nanotube/ZnO nanorod hybrid nanocomposite (ZTN) photoanodes were synthesized, characterized and assembled as dye-sensitized solar cells (DSSCs) at optimum conditions for improving photovoltaic efficiency. The self-organized and high ordered TiO 2 nanotube arrays were growth on titanium foil by anodic oxidation as a substrate for ZnO decoration by hydrothermal method. Zinc nitrate hexahydrate and hexamethylenetetramine precursor concentrations were varied to designate the optimum ZnO decoration density for enhanced photoconversion efficiency. XRD, FESEM and XPS results showed that the crystal structure, morphology, elemental composition and density of ZnO nanorods on the surface of TiO 2 nanotubes are very sensitive to ZnO precursor concentrations. It is found that, the highest overall efficiency of DSSC based on ZTN photoanode was measured 1.8% for precursor concentration of 60 mM which was more than double compared to DSSC based on bare-TiO 2 nanotubes (0.8%). The improvement of DSSC efficiency originates from suppressing the recombination rate and decreasing the charge transfer resistance due to synergetic effect between TiO 2 nanotubes and ZnO nanorods.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    RDL Kalıcı Kaydıİncele
  • ArticleYalnız künye2019
    Design and implementation of an IBC reduced voltage across output capacitor

    Ting, Naim Suleyman; Sahin, Yakup; Yetgin, Halil

    Interleaved boost converter (IBC) is equal to two-boost converter operating in parallel. IBCs are more advantageous than conventional boost converters. Input current of the interleaved converter is less fluctuated compared to that of the boost converter. In this paper, a new IBC structure is introduced unlike the conventional IBC structure. In the presented converter, the place of output filter capacitor is changed unlike the conventional IBC and thus, the voltage across the output filter capacitor is reduced about Vi. The proposed IBC performs similar experimental results compared to that of the conventional IBC. Besides, the proposed IBC enables the utilization of an output filter capacitor even with lower voltage, and thus the cost of IBC is reduced. The analysis of operating stages of the presented converter is conducted for D < 50% and D > 50% modes. Finally, an experimental setup of the presented converter is realized along with the parameters of 640 W and 20 kHz.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    RDL Kalıcı Kaydıİncele
  • ArticleAçık Erişim2018
    Effects to System Performance of Different PWM Techniques in Field Oriented Speed Control with back-to-back Converter of PMSG

    Şahin, Yakup; Ting, Naim Suleyman

    In this paper, the performance of space vector pulse width modulation (SVPWM), sinusoidal pulse width modulation(SPWM) and hysteresis current control (HCC) techniques used in speed control with back to back converter ofpermanent magnet synchronous generator (PMSG) used in wind turbines are comparatively analyzed. The comparativeanalysis includes dynamic response, total harmonic distortion (THD), torque ripple and current ripple. Furthermore,SVPWM and SPWM are compared in terms of the using DC link voltage. Analysis of system is realized withMATLAB/Simulink program. PMSG used in simulations is surface mounted, bipolar and its power is 1.8 kW. Also, theenergy of PMSG is transferred to grid with Field Oriented Control (FOC). According to analysis results, it has beenobserved that SVPWM generally has more effective results than both HCC and SPWM control techniques. Finally, it isobserved that SVPWM can produce about 15 percent higher than SPWM in output voltage

    • SDG 7 · Erişilebilir ve Temiz Enerji
    RDL Kalıcı Kaydıİncele
  • ArticleAçık Erişim2018
    Energy and environmental evaluation of a pcm wall covered with novel triple glass

    Kara, Yusuf; Seyhan, Aslıhan Kurnuç

    Research was conducted to investigate the performance of phase change material (PCM) walls for solar spaceheating. The PCM walls were consisted of brick walls, plasterboards containing PCMs and novel triple glazingunits. South façade of a test room was constructed using the PCM walls for heating the test room with solarthermal energy. The overall efficiency of the PCM walls was experimentally determined on a monthly basis. Inaddition to experimental analysis, a theoretical energy analysis of the PCM walls based on 10-year meanmeteorological data was performed to provide a more general conclusion about the performances of the PCMwalls. Besides, reduction in CO2 from the test room owing to PCM wall was also calculated. Theoretical analysisresults showed that, the reduction of CO2 emission on a monthly basis varied from 57 to 7% during the heatingperiod. Heating period is from October through May. Reduction of CO2 emission was 16% on an annual basis.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 11 · Sürdürülebilir Şehirler ve Topluluklar
    • SDG 12 · Sorumlu Üretim ve Tüketim
    • SDG 13 · İklim Eylemi
    RDL Kalıcı Kaydıİncele
  • ArticleAçık Erişim2018
    The Investigation of Heating Conduction Coefficients of Different Heating Isolation Materials Used in buildings in Circumstance of Erzincan Province Using Thermocouple and Thermal Camera

    Kaya, Mehmet; Ulusu, İsmet; Kotan, Temel; Fırat, İlker

    Given the fact that 35 % of total energy is consumed in buildings and % 80 of that energy is used as heating purposes, it is of importance that heating isolation material applied to buildings as well as more efficient heating systems set up in buildings provides large energy savings. Providing desired performance in heating isolation is directly correlated to properties of heating isolation material along with to thoroughly complying to application techniques of isolation materials. Expanded perlit is considered to be alternative heating isolation material because it has close isolation values to that of other isolation materials, and its lifetime approaches to infinity due to its puzolanik features gaining strength with time, and it prevents heat bridges as isolation process is done as whole in layer, and it has high fire durability, sound isolation, and it prevents the formation of vapor between wall and plaster surface and so that prevents mold and bacteria with the help of breathing the air, and it doesn`t emit harmful chemical substance due to fact that it is natural. In this study, an experimental room was made in Erzincan province and compared the thermal insulation performance of perlite, which is the most widely used thermal insulation material today, with expanded EPS. As a result of the evaluation of the received measurement data, it has been determined that 8 cm expanded perlite and 6 cm EPS thermal insulation material have equal thermal insulation capacity.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    RDL Kalıcı Kaydıİncele
  • ArticleAçık Erişim2018
    Enerji tüketimi ve ekonomik büyüme arasındaki ilişki: bdt ülkeleri örneği

    Manga, Müge; Balli, Esra; Güney, Çıler Sıgeze

    Enerji tüketimi ile ekonomik büyüme arasındaki ilişkinin incelenmesi ekonomik büyüme üzerinde enerjitüketiminin rolü hakkında bilgi vermesi ve politika yapıcılarının enerji politikaları oluşturabilmeleri açısındanoldukça büyük öneme sahiptir. Bu çalışmada, Ermenistan, Azerbaycan, Gürcistan, Kazakistan, Kırgızistan,Moldova, Beyaz Rusya, Rusya, Türkmenistan, Tacikistan, Ukrayna ve Özbekistan’dan oluşan Bağımsız DevletlerTopluluğu (BDT)’ndaki enerji tüketimi ile ekonomik büyüme arasındaki ilişki 1992-2013 yılları esas alınarakpanel Düzeltilmiş En Küçük Kareler Yöntemi (FMOLS) ve Dumitrescu-Hurlin (2012) panel nedensellik testi ileanaliz edilmiştir. Elde edilen sonuçlar, mevcut yıllarda BDT ülkelerinde enerji tüketimi ile ekonomik büyümearasında çift yönlü nedensellik ilişkisinin olduğunu göstermektedir. Bunun yanında BDT’ye üye ülkelerin doğalkaynak zenginlikleri önemli ölçüde farklılık göstermektedir. Bu doğrultuda, politika yapıcılarının etkinekonomik ve çevresel politikalar oluşturabilmeleri için ekonomik büyüme ile enerji tüketimi arasındaki ilişkininboyutu hakkında bilgi edinmeleri önem kazanmaktadır.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 8 · İnsana Yakışır İş ve Ekonomik Büyüme
    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    RDL Kalıcı Kaydıİncele
  • ArticleAçık Erişim2018
    Investigation of Biogas Potential of Animal Wastes in Erzincan Province

    Badem, Anıl; Seyhan, Aslıhan Kurnuç

    The fossil-based energy resource's is non-renewable and causing negative effects on the environment. Because of the ever-increasing need for energy, the more efficients use of existing resources and is necessary move towards domestic and renewable energy sources. The main livelihood of agriculture and animal husbandry is 37% of Erzincan province's surface area is composed of meadow and grassland. This has led to the cultivation of feed plant varieties in large areas and the development of animal production. In Erzincan province where cattle, sheep and poultry are grown, 434469 tons of animal waste is obtained annually. Biogas production is one of the best ways to use these wastes in a sustainable and efficient way. In this study, the amount of biogas available per year from Erzincan province animal wastes was calculated as 15511011 m3, electric energy 38025864 kWhe and heat energy 35818027112 kcal using data from Erzincan Cattle Breeders Association and Food, Agriculture and Livestock Provincial Directorate. It is observed that Erzincan has a potential of 4.3 MW in terms of biogas-derived electricity generation power and has an important capacity for biogas and energy production values

    • SDG 2 · Açlığa Son
    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 12 · Sorumlu Üretim ve Tüketim
    • SDG 13 · İklim Eylemi
    • SDG 15 · Karasal Yaşam
    RDL Kalıcı Kaydıİncele
  • ArticleAçık Erişim2018
    THE MODELING AND ANALYSIS OF A POWER TRANSMISSION LINE SUPPLIED BY A SOLAR POWER PLANT

    Can, Erol

    This article deals with the energy transmission line system which feeds from solar energy at the MATLAB Simulink. So, direct voltage is considered to be converted as an alternating voltage by a 35-level inverter after the solar power plant which has the power of 110 MW produce 360 kV of direct voltage. A line which covers 240 km of distance is preferred to transmit electrical power from the A1 point to an A2 point. Due to this, the required mathematical equations are calculated with a circuit analyzing method for the line modeling in the simulation. Experiments on the model are carried out at the MATLAB Simulink after the creation of an energy transmission line. After that, when measurements are made taking into consideration the A2 node; the capacitor voltage, the transformer current, the A2 node current, and the fault current, values are given according to the converted voltage at the frequencies of 100 Hz, 80 Hz, and 50 Hz. The obtained results demonstrate the success of the proposed line system, while power is distributed with eliminated fault at a long distance at different frequencies.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    RDL Kalıcı Kaydıİncele
  • ArticleAçık Erişim2018
    An experimental study on premixed CNG/H2/CO2 mixture flames

    Yilmaz, Ilker; Yilmaz, Harun; Cam, Omer

    In this study, the effect of swirl number, gas composition and CO2 dilution on combustion and emission behaviour of CNG/H2/CO2 gas mixtures was experimentally investigated in a laboratory scale combustor. Irrespective of the gas composition, thermal power of the combustor was kept constant (5 kW). All experiments were conducted at or near stoichiometric and the local atmospheric conditions of the city of Kayseri, Turkey. During experiments, swirl number was varied and the combustion performance of this combustor was analysed by means of centreline temperature distributions. On the other hand, emission behaviour was examined with respect to emitted CO, CO2 and NOx levels. Dynamic flame behaviour was also evaluated by analysing instantaneous flame images. Results of this study revealed the great impact of swirl number and gas composition on combustion and emission behaviour of studied flames.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 13 · İklim Eylemi
    RDL Kalıcı Kaydıİncele
  • ArticleYalnız künye2018
    Combustion characteristics of premixed hydrogen/air flames in a geometrically modified micro combustor

    Yilmaz, Ilker; Yilmaz, Harun; Cam, Omer; Ilbas, Mustafa

    Main challenges for a fuel efficient micro scale combustion are rooted from size restriction of micro combustors which results with inappropriate residence time of fuel/air mixture and intensified heat losses due to relatively high surface to volume ratio of such devices. One way of increasing energy output of micro combustors is to optimize its geometry by considering simplicity and easy manufacturability. In this study, effect of combustor geometric properties on combustion behavior of premixed hydrogen/air mixtures was numerically investigated. For this purpose, an experimentally tested micro combustor's geometric properties were modified by establishing a backward facing step which is varying distance from combustor inlet and has varying step height, and adding opposing cavities which are varying distance from combustor inlet and have constant length to depth ratio into the flow area. Modeling and simulation studies were performed using ANSYS Design Modeler and Fluent programs, respectively. Combustion behavior was analyzed by means of centerline and outer wall temperature distributions, amount of heat transferred through combustor wall, conversion ratio of input chemical energy to utilizable heat, and species distributions. Turbulence model used in this study is Renormalization Group (RNG) k-ε. Multistep combustion reaction scheme with 9 species and 19 steps was simulated using Eddy Dissipation Concept model (EDC). Results showed that backward facing step in the flame region alters reaction zone distribution, flame length and shape, and consequently temperature value and distribution throughout the combustor. Lastly cavity was found to slightly increase peak temperature value.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    RDL Kalıcı Kaydıİncele
  • ArticleYalnız künye2018
    Thermoeconomic modeling and multi-objective evolutionary-based optimization of a modified transcritical CO2 refrigeration cycle

    Khanmohammadi, Saber; Goodarzi, Mohsen; Khanmohammadi, Shoaib; Ganjehsarabi, Hadi

    In this study, thermoeconomic optimization is applied to a modified transcritical (CO2) refrigeration cycle. Modified cycle includes an extraction of saturated vapor as a coolant stream from the separator feed to the intercooler. In order to perform multi criteria optimization two objective functions consist of cooling capacity and annual cost rate are chosen. Gas cooler temperature (Tgc), gas cooler pressure (Pgc), extraction mass flow rate (α) and evaporator temperature (Tev) are selected as decision variables based on parametric study. The thermodynamic and economic modeling of the system is performed. To determine analytical, objective functions GMDH (group method of data handling) neural network method is used and finally with a developed code in Matlab optimal values of decision variables have been obtained. In addition, to better understanding the change of decision variables in optimum point, the scatter distribution of these variables is carried out.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 13 · İklim Eylemi
    RDL Kalıcı Kaydıİncele
  • Book ChapterYalnız künye2018
    Investigation of an optimal operating condition for a micro combustor regarding basic thermophotovoltaic system requirements

    Yilmaz, Harun; Cam, Omer; Yilmaz, Ilker; Nizetic, S; Papadopoulos, A

    In this study, effects of equivalence ratio and thermal power on combustion and emission behaviour of premixed hydrogen air mixtures were numerically investigated by constructing 3D micro combustor models. Combustion behaviour was analysed by examining combustor outer wall and centreline temperature profiles, and convective and radiative heat transfer quantities. Besides, emission behaviour was analysed in terms of centreline NOx profiles and NOx amounts emanated from exhaust of the micro combustor. Regarding these, optimal operating condition with respect to combustion performance and pollutant emissions was investigated by varying thermal power and equivalence ratio. Turbulence model used in this study is RNG k-ε (Yilmaz et al. Int J Hydrog Energy 42:25744–25755, 2017). Multistep combustion reaction process with 9 species and 19 steps was simulated using Eddy dissipation concept model. Data obtained from this study was validated against published experimental data (Tang et al. Int J Hydrog Energy 40:2396–2403, 2015). Results showed that optimal operating condition can be gained at 0.8 equivalence ratio and 1200 ml/min hydrogen flux.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 13 · İklim Eylemi
    RDL Kalıcı Kaydıİncele
  • ArticleYalnız künye2018
    Increasing power and torque capability of brushless direct current motor by employing 150-degree conduction mode controlled three-phase voltage source inverter

    Ozgenel, Mehmet Cihat

    With the reduction of magnet costs and the production of high-energy magnets in small sizes, permanent magnet brushless motors are used widely in various applications from household to medical, industrial, and automation applications. Furthermore, permanent magnet brushless motors have some significant advantages over the other conventional motors such as induction and brushed motors. Due to the popularity of brushless motors, they have become the focus of interest of researchers. From the past 30 years to today, the researchers have carried out numerous studies in relation to brushless motors. These studies are generally sensorless control, adaptive control, different Proportional Integral and Derivate (PID) applications, fuzzy control, PI-fuzzy and PID-fuzzy control and different Pulse Width Modulation applications and to eliminate torque ripple and other control algorithms. Permanent magnet brushless motors can be divided into two main groups. One is the permanent magnet synchronous motor and the other one is the permanent magnet brushless direct current motor (BLDCM). BLDC motors are the most preferred in applications due to their low cost and relatively simple drivers. BLDC motors are run with the classical 120-degree conduction mode voltage source inverter (VSI). Because BLDC motors run with 120-degree conduction mode inverters, power and torque produced by BLDC motors are less than their capacity, whereas BLDC motors can provide a better dynamic response, higher power, and torque by employing 150-degree conduction mode controlled VSI. In this experimental study, it is aimed to design and manufacture a versatile VSI which can control the BLDC motor in both 120 and 150-degree conduction modes. Then, BLDC motor is run in two conduction modes employing the purposed inverter under various loads, and the torque, power, and speed performance of the motor were analyzed to demonstrate the effect of the two commutation methods on BLDC motor performance. The results of this comparative experimental study have shown that the 150-degree conduction mode-controlled inverter provides with the BLDC motor generating higher power, torque, and speed than the inverter with 120-degree conduction mode.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    RDL Kalıcı Kaydıİncele
  • ArticleAçık Erişim2018
    Analysis and performance with vertical divided multilevel voltage on phase of induction engine

    Can, Erol

    In this study, the quality of the transformed energy form is analysed after comparing the single-phase induction motor operated by the SPWM inverter to the 15-level LPWM inverter. Firstly, multilevel inverter and pulse width modulation are designed. The multi-level inverter has sixteen IGBT switches because inverter circuit is constructed with high multilevel inverter topology. Linear pulse width modulation (LPWM) is designed for operation of sixteen switches in the inverter circuit. Secondly, equations of the induction motor are calculated according to d-q axis with creating 15-level alternating voltage. After described equations, 15-level inverter running single phase induction motor is formed at the Matlab Simulink. The obtained results are analyzed according to motor performance and harmonic distortion of the created alternating energy after the proposed model is simulated. Finally, Simulation results of the proposed system are compared with simulation results of SPWM inverter controlling the single-phase induction motor.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    RDL Kalıcı Kaydıİncele
  • ArticleYalnız künye2018
    Fabrication of TiO2/ZnO/Pt nanocomposite electrode with enhanced electrocatalytic activity for methanol oxidation

    Özdokur, Kemal Volkan; Çırak, Burcu Bozkurt; Caglar, Bulent; Çırak, Çağrı; Karadeniz, Sibel Morkoç; Kılınç, Tuba; Erdoğan, Yaşar; Ekinci, Ali Ercan

    Platinum decorated heterogeneous catalysts for methanol oxidation reaction have crucial importance for the commercial sustainability of Direct Methanol Fuel Cells (DMFC). In this study, TiO2/ZnO/Pt nanocomposite film was fabricated as a promising electrocatalytic surface to enhance methanol oxidation in alkaline medium. Firstly, an TiO2/ZnO layer was prepared via DC sputtering followed by electrodeposition techniques on FTO electrode and then platinum nanoparticles were decorated onto the obtained nanocomposite film for the first time. The characterization of the developed transparent films was performed by using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cycling voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The XRD, FESEM and XPS results showed that metallic Pt nanoparticles were uniformly distributed onto the TiO2/ZnO film consisting of anatase TiO2 and wurtzite ZnO layers with a thickness of ca. 370 and 320 nm, respectively. Five cycles of deposition of ZnO and Pt nanoparticles showed best catalytic activity after optimization. The oxidation peak of 0.5 M methanol at TiO2/ZnO/Pt was located at −0.17 V and the corresponding peak current increased about 10- and 5-fold in comparison to FTO/Pt and FTO/TiO2/Pt electrodes, respectively.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    RDL Kalıcı Kaydıİncele
  • ArticleAçık Erişim2018
    Aircraft gas turbine engine health monitoring system by real flight data

    Yildirim, Mustagime Tülin; Kurt, Bülent

    Modern condition monitoring-based methods are used to reduce maintenance costs, increase aircraft safety, and reduce fuel consumption. In the literature, parameters such as engine fan speeds, vibration, oil pressure, oil temperature, exhaust gas temperature (EGT), and fuel flow are used to determine performance deterioration in gas turbine engines. In this study, a new model was developed to get information about the gas turbine engine's condition. For this model, multiple regression analysis was carried out to determine the effect of the flight parameters on the EGT parameter and the artificial neural network (ANN) method was used in the identification of EGT parameter. At the end of the study, a network that predicts the EGT parameter with the smallest margin of error has been developed. An interface for instant monitoring of the status of the aircraft engine has been designed in MATLAB Simulink. Any performance degradation that may occur in the aircraft's gas turbine engine can be easily detected graphically or by the engine performance deterioration value. Also, it has been indicated that it could be a new indicator that informs the pilots in the event of a fault in the sensor of the EGT parameter that they monitor while flying.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    RDL Kalıcı Kaydıİncele