Papers by Erol S U B M I T P A P E R S T O E C R E S . N E T I C M E C E . O R G I N T C E C . O R G Kurt
Journal of energy systems, Apr 1, 2024
This research focuses on exploring the nanosecond laser-driven coil systems capable of generating... more This research focuses on exploring the nanosecond laser-driven coil systems capable of generating kT magnetic fields and the diverse applications of this system. Through investigating the effects of laser parameters and coil structures, the aim of this study is to unveil the physics of these generated intense magnetic fields. The outcomes gained from this research give an important and fundamental understanding on high magnetic field production, informing the development in laser-driven systems. The implications of this study extend to plasma physics, astrophysics simulations and fusion research. Furthermore, the study explains the advantages and applications of these intense magnetic fields and includes measurements of laser pulse powers according to coil materials.
Turkish Journal of Electrical Engineering and Computer Sciences, Jul 1, 2022
In this communication, the novel low cost hybrid energy harvester combining rectifying antenna wi... more In this communication, the novel low cost hybrid energy harvester combining rectifying antenna with the solar cell for feeding the low power energy systems are reported. The bioinspired leaf shaped monopole antenna is designed to work in the most used communication frequency bands such as GSM-1800, UMTS-2100, WIFI-2.45 and LTE-2.65 GHz for the energy harvesting purposes and microstrip low pass filter is also added on the feeding line for the second harmonic rejection for increasing the efficiency of the harvester. The solar cell is placed on the ground plane of the designed leaf shaped antenna for using volumetric space efficiently and obtain a more compact system. The implemented prototype harvester generate 76 mV, 120 mV and 90 mV when the same type receiver antenna feed from the 25 dBm power from the RF source located at a distance of 1 m which satisfies the far field condition of the antenna without solar cell at the 2.15 GHz, 2.45 GHz and 2.65 GHz frequency bands, respectively. After the illumination of its solar cell component with 165 lux, the total harvested voltages are measured as 150 mV, 170 mV and 190 mV at the same frequency bands, respectively.
International Journal of Renewable Energy Development, Feb 18, 2018
The efficiencies of nuclear power plants are rather poor having the ratio %30 by using the conven... more The efficiencies of nuclear power plants are rather poor having the ratio %30 by using the conventional energy/exergy tools. According to that information, large amount of energy is wasted during condensation and thrown out to the environment. Thermoelectric generator (TEG) system has a potential to be used as a heat exchanging technology to produce power with a relatively low efficiency (about 5%) and it can transform the temperature difference into electricity and generate clean electrical energy. In the present study, we offer a novel system to recover the waste heat from a VVER-1000 nuclear power plant. The heat transfer of the TEG is analyzed numerically with respect to the various temperature ranges and constant mass flow rate of the exhaust steam entering the system. In the analyses, different hot temperature ranges (35ºC, 45ºC and 55ºC) and a constant cold temperature (i.e. 18ºC) are used for a HZ-20 thermoelectric module and it has been proven that the designed TEG can produce the maximum output power of 76.956 MW for a temperature difference ∆T=37 and the conversion efficiency of 3.854% sits. The TEG is designed for the condenser of a 1000 MW nuclear power plant. It's shown that about 2.0% increasing in the power plant efficiency is expected by using the selected thermoelectric generator in the condensation cycle.
International Conference on Applied Electronics, Oct 26, 2015
The dynamics of a resistively coupled nonidentical Josephson junction (JJ) circuit is explored an... more The dynamics of a resistively coupled nonidentical Josephson junction (JJ) circuit is explored and a new control strategy is applied in order to smoothen the unstable regimes. In such a system, periodic, quasiperiodic and chaotic behaviors have been encountered worldwidely. In addition, the existence of the hyperchaos has also been declared by Kurt and his coworker. It is understood that the dynamic features strictly depend on the coupling resistance R cp . Indeed the decrease in R cp causes a sudden increase in Lyapunov exponents, which prove the chaoticity of the system. Since a wide chaotic region is encountered, the control of the system becomes important for a number of engineering applications. A new control system approach has been applied in order to solve this problem.
Journal of Energy Systems
In the present paper, a forecasting study on the monthly electricity generation of Türkiye from t... more In the present paper, a forecasting study on the monthly electricity generation of Türkiye from the conventional and renewable resources is performed. The effect of the CoVid-19 pandemic on the sector has been considered. For this aim, the trend before the pandemic has been initially considered and later the post-pandemic situation has been handled. It has been observed that the electricity generation supply/demand mechanism changes drastically compared to the pre- and post-pandemic cases. The rate of the generation from the renewable resources especially shows a sharp variation compared to the rates from the fossil fuels. According to the forecasting scenario, in 2021, the electricity generation shows different attitudes with regard to the resources used. In 2022, especially increasing trends are expected for wind, biogas, natural gas, imported coal and fuel oil, whereas diesel and mineral coal are expected to be decreased in Türkiye.
JOM
The presence of suspended particles in liquid fluids is one of the main reasons for hydraulic sys... more The presence of suspended particles in liquid fluids is one of the main reasons for hydraulic system failure. Metallic impurities in particular increase the presence of toxic substances in wastewater; therefore, it is vital to study and address the behaviour of such particles in water flows. The current literature lacks studiees approaching the combined effect of different filtering techniques in backward-facing step (BFS) flows. This work aims to analyse the behaviour of iron filings within a BFS system, making use of a combined experimental 2D PIV/PTV–3D uRANS computational approach. Experiments and computations are performed at a Reynolds number $$\mathrm{{Re}}_{H} = 3684.63$$ Re H = 3684.63 . Computational measurements are performed in several planes whereas the experimental campaign is focused on the dynamics of the particles through the streamwise middle plane. A half plane reattachment length of $$X_{\rm{r}} = 11.73h$$ X r = 11.73 h is measured for an inlet flow turbulence in...
WSEAS TRANSACTIONS ON ENVIRONMENT AND DEVELOPMENT, 2021
In this paper, a new system is proposed to improve the thermodynamic and economic indicators of s... more In this paper, a new system is proposed to improve the thermodynamic and economic indicators of solar room heating. The heat pump is integrated with a conventional solar heating system, in which the temperature of the collected heat is reduced by 20 °C to 30 °C to increase the efficiency of solar energy collection. The low-temperature heat collected by the solar collector is increased using a heat pump to generate high-temperature heat for indoor heating in winter and low-pressure process steam for industrial use in other seasons. The results show that the efficiency of the solar collector has increased by 30.50%, its annual effective operating time has reached 2000 hours, which is about four times more than that of a conventional solar heating system. In addition, the parameters of the solar collector area, the volume of the storage tank and the power of the heat pump have been optimized. This work provides a new way to use solar energy more efficiently and economically. Energy ana...
Energy efficiency has always been a major challenge for the scientist and the engineers. However,... more Energy efficiency has always been a major challenge for the scientist and the engineers. However, in recent years, the increased public concern for the preservation of natural resources and the protection of the environment has strongly stimulated the research and development activities in this area. More than 20,000 technical papers written in 2016 and stored in "Scopus" database have "energy efficiency" in their title, in their abstract or in their list of keywords. There were less than 4000 in 1996.
JOM, 2021
This work presents the results of experimental analysis of the correlation between open-circuit v... more This work presents the results of experimental analysis of the correlation between open-circuit voltage at 0% and the state of charge of a set (3 9 6) of high-temperature valve-regulated lead acid batteries, which provides a valuable health diagnosis tool when performing predictive maintenance actions. The proposed test could be executed after any emergency event in the battery system. It offers an alternative to the integration ampere hours, simplifying the diagnostic system, and can be used in many applications where the diagnosis can be made by monitoring the discharge voltage to a defined controlled value. By testing three different sealed, high-temperature lead acid battery models, it has been proved that open-circuit-voltage measurement at 0% state of charge is valid to evaluate health status and is applicable to different manufactures. In addition, the first derivative value calculation of the relaxation voltage over time provides accurate correlation with the state of health of the battery. The method proposed minimizes diagnosis times providing an easier way to implement the method in real systems.
komplexer raum-zeitlicher Dynamik ausbilden, die sogar oft einen größeren Einzugsbereich haben. D... more komplexer raum-zeitlicher Dynamik ausbilden, die sogar oft einen größeren Einzugsbereich haben. Der Fall kleiner P erwies sich als noch komplizierter, da viele Bifurkationen subkritisch waren. Im Kapitel 3 wurde das magnetische Ekman-Couette Problem untersucht. Eine Fluidschicht befindet sich zwischen zwei Platten, die in entgegengesetzter Richtung mit konstanter Geschwindigkeit (parametrisiert durch die dimensionslose Reynoldszahl Re) bewegt werden. Die Anordung wird um eine Achse senkrecht zu den Platten rotiert, das Magnetfeld zeigt in die gleiche Richtung. Es bildet sich im Grundzustand ein Geschwindigkeitsgradient senkrecht zu den Platten aus. Ohne Rotation der gesamten Anordnung ergibt sich so eine einfache Couetteströmung. Sie ist linear stabil für beliebige Re. Bei endlichem τ bilden sich jedoch eine Grenzschicht an den Platten aus, in der sich der Geschwindigkeitsgardient konzentriert ("Ekman Layer"); er liegt dann in einer Ebene, die nicht parallel zur Zugrichtung der Platten ist. Die Grenzschichten werden linear instabil gegen Rollenstrukturen, die stationär sein können aber auch wie eine ebenen Welle laufen können. Es werden wieder die im Kapitel 1 beschrieben Methoden angewendet, wobei die Existenz einer Strömung schon im Grundzustand die Rechnungen deutlich komplizierter macht. Abgesehen von der Berücksichtigung des endlichen Magnetfeldes (Q = 0) wurden schon bekannte lineare und nichtlineare Analysen für Q = 0 deutlich erweitert durch Verbesserung der numerischen Techniken. Besonderes Augenmerk wurde auf die zwei unterschiedlichen Typen (I/II) von laufenden Wellen gelegt, die sich sowohl in ihrer Ausbreitungsrichtung als auch ihre Frequenz unterscheiden. Spektakuläre Auswirkungen eines endlichen Magnetfeldes wurden allerdings nicht endeckt. Es wirkt generell stabilisierend und führt eher zu quantitativen Verschiebung von Stabilitätsgrenzen. Es besteht einige Hoffnung, daß in der nächster Zeit Experimente in Angriff genommen werden, mit denen sich unsere Ergebnisse direkt vergleichen lassen. Mit den in dieser Arbeit entwickelten Codes stehen alle theoretischen Hilsmiitel zu ihrer Analyse bereit.
2015 International Conference on Applied Electronics (AE), 2015
The dynamics of a resistively coupled nonidentical Josephson junction (JJ) circuit is explored an... more The dynamics of a resistively coupled nonidentical Josephson junction (JJ) circuit is explored and a new control strategy is applied in order to smoothen the unstable regimes. In such a system, periodic, quasiperiodic and chaotic behaviors have been encountered worldwidely. In addition, the existence of the hyperchaos has also been declared by Kurt and his coworker. It is understood that the dynamic features strictly depend on the coupling resistance Rcp. Indeed the decrease in Rcp causes a sudden increase in Lyapunov exponents, which prove the chaoticity of the system. Since a wide chaotic region is encountered, the control of the system becomes important for a number of engineering applications. A new control system approach has been applied in order to solve this problem.
Electrical and Electronics Engineering: An International Journal, 2017
In recent years, there is a significant increase in the number of devices with low power consumpt... more In recent years, there is a significant increase in the number of devices with low power consumption. The energy requirements of these devices are provided by chemical batteries. The batteries must be charged at regular times, and cause some problems such as environmental pollution. RF energy harvesters are an alternative energy source for the batteries. In this study, the responses of 900 MHz RF energy harvester, which was previously tested, are estimated using an Artificial Neural Network (ANN) method in different states. For this aim, the output power values are determined by using the input power and the frequency of the signal and the load resistances connected to the energy harvester.
Journal of Energy Systems, 2019
An initial design for a power circuit of a new plasma system is proposed and implemented in MatLa... more An initial design for a power circuit of a new plasma system is proposed and implemented in MatLab code. The plasma device is a torus and requires an excitement of wires, which are wrapped around the torus for a toroidal field and a poloidal field coil placed at the outer part of the device. This poloidal coil structure ignites an electrical field inside the chamber and that yields to a circular magnetic field inside the plasma. The proposed electrical design for this poloidal field equipment has some components including the alternating current unit and the direct current one. The circuit first uses an ac-dc converter, in order to transfer the ac grid to the dc one. Then it uses a switching scheme and a discharge circuit. The operation voltages for the poloidal field are estimated to be 1 kV, respectively. It has been proven that the designed system can produce an almost dc current with 66 V fluctuation, which is under the limit of 6%, considering the high voltage of 1kV.
Energies, 2019
In this paper, the results of the sensitivity analysis applied to a fuel cell hybrid power system... more In this paper, the results of the sensitivity analysis applied to a fuel cell hybrid power system using a fuel economy strategy is analyzed in order to select the best values of the parameters involved in fuel consumption optimization. The fuel economy strategy uses the fuel and air flow rates to efficiently operate the proton-exchange membrane (PEM) fuel cell (FC) system based on the load-following control and the global extremum seeking (GES) algorithm. The load-following control will ensure the charge-sustained mode for the batteries’ stack, improving its lifetime. The optimization function’s optimum, which is defined to improve the fuel economy, will be tracked in real-time by two GES algorithms that will generate the references for the controller of the boost DC-DC converter and air regulator. The optimization function and performance indicators (such as FC net power, FC electrical efficiency, fuel efficiency, and fuel economy) have a multimodal behavior in dithers’ frequency. ...
Politeknik Dergisi, 2019
A new secure image communication system has been designed and implemented based on a synchronized... more A new secure image communication system has been designed and implemented based on a synchronized chaotic circuit. The new chaotic circuit, which has recently proposed by one of the authors contains a resistor, two inductors, and two diodes (i.e. R2L2D). The synchronization part operates with a master – slave configuration. In order to achieve the real-time communication, initially the analog master circuit has been implemented to generate chaotic sequences of numbers. Then, that analog tool has been transmitted to a computer via an analog/digital converter and a hidden image has been obtained. Besides, the slave circuit has also received a copy of that chaotic sequences in order to use it in subtraction process of image gray levels. The digital chaotic image has been transmitted to the slave circuit via a digital/analog converter with an efficient method and the decrypted image has been obtained in real-time. The advantage of that technique over the conversional ones is that it doe...
Energies, 2018
Within the context of an energy transition towards achieving a renewable low-impact energy consum... more Within the context of an energy transition towards achieving a renewable low-impact energy consumption system, this study analyses how bottom-up initiatives can contribute to state driven top-down efforts to achieve the sustainability related goals of (1) reducing total primary energy consumption; (2) reducing residential electricity and heat consumption; and (3) increasing generated renewable energy and even attaining self-sufficiency. After identifying the three most cited German bottom-up energy transition cases, the initiatives have been qualitatively and quantitatively analysed. The case study methodology has been used and each initiative has been examined in order to assess and compare these with the German national panorama. The novel results of the analysis demonstrate the remarkable effects of communal living, cooperative investment and participatory processes on the creation of a new sustainable energy system. The study supports the claim that bottom-up initiatives could also contribute to energy sustainability goals together within the state driven plans. Furthermore, the research proves that the analysed bottom-up transitions are not only environmentally and socially beneficial but they can also be economically feasible, at least in a small scale, such as the current German national top-down energy policy panorama.
International Journal of Hydrogen Energy, 2017
This paper presents the capability of the Asymptotic Perturbed Extremum Seeking Control (aPESC) s... more This paper presents the capability of the Asymptotic Perturbed Extremum Seeking Control (aPESC) scheme to track the Global Extreme on multimodal patterns. The multimodal patterns are simulated based on power characteristics generated by a photovoltaic (PV) array under Partial Shading Conditions (PSCs). The aPESC scheme is tested to evaluate the performance of locating, searching and tracking of the Global Maximum Power Point (GMPP). The following performance indicators such as the searching resolution, tracking accuracy, tracking efficiency, and tracking speed are used to compare the performance of the GMPP tracking (GMPPT) algorithms. The aPESCH1 scheme proposed has been implemented in MATLAB/Simulink package to evaluate the performance indicators mentioned above. The results prove that the proposed aPESCH1 scheme is effective and simple to be implemented.
International Journal of Hydrogen Energy, 2017
The features of the new designed and constructed harvester are examined. The harvested power of t... more The features of the new designed and constructed harvester are examined. The harvested power of three piezoelectric layers having different masses (i.e. different natural frequencies) has been explored. These layers have the same length around the harvester body, whereas a permanent magnet (PM) attached to the shaft rotates by low speed wind and this PM repels these three piezoelectric layers with a 120 phase shift. Since PM and the PMs located to the tip of the layers do not contact, this system improves the lifetime of the harvester. The measured harvested power in the low wind speeds (i.e. 1.75 m/s) is of the order of 0.2 mW. The waveform includes many subharmonic and superharmonic components, hence the total harmonic distortion (THD) is found around 130%, which is fairly high due to nonlinear effects. Although the system shows an high THD, the 20% of the signal can be rectified and stored in the capacitor for the use of harvested energy. A scenario has also been created for a resistive load of R L ¼ 1 MU and 100 kU for various wind speeds and it has been proven that the harvester can feed the load at even lower wind speeds. In addition, extra power beyond the usage of the load can be stored into the capacitor. The proposed harvester and its rectifying unit can be a good solution for the energy conversion procedures of low-power required machines.
This research deals with the energy harvesting issues of a piezoelectric harvester under magnetic... more This research deals with the energy harvesting issues of a piezoelectric harvester under magnetic excitation. Following the determination of dynamic equations of the system the remaining part of the paper presents the experimental findings. The system is characterized by the magnetic field excitation frequency f, distance from the electromagnet tip to equilibrium point of harvester d, and amplitude of the magnetic field strength (i.e. electromagnet voltage). The experimental data of displacement, velocity and voltage outputs are used via a data acquisition card in the cases of different parameters. According to the results, the harvested power strictly depends on f, and the total harmonic distortion (THD) as a tool for the determination of complexity indicates a substantial increment at low power cases. Apart from some previous studies, it is proven that nonlinear vibrations decrease the output power under changeable magnetic excitation.
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Papers by Erol S U B M I T P A P E R S T O E C R E S . N E T I C M E C E . O R G I N T C E C . O R G Kurt