Nevsehir, Turkey
Nevsehir, Turkey

Nevşehir University, aka Nevşehir Hacı Bektaş Veli University, is a public institute of higher education established in 2007 and located in Nevşehir, Turkey. Wikipedia.

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Aslan A.,University of Nevsehir
Renewable and Sustainable Energy Reviews | Year: 2011

This study is the first attempt to investigate the stationarity of natural gas consumption for 50 US states by employing nonlinear unit root test over the period 1960-2008. We concluded that natural gas consumption in approximately over 60% of states follow a nonlinear behavior. While for 27 US states, natural gas consumption is a non-stationary process, then any shock to natural gas consumption is likely to be permanent and such policies will have a permanent impact, for the rest of 23 states natural gas consumption is a stationary process that any shock to natural gas consumption is to be transitory. © 2011 Elsevier Ltd. All rights reserved.

Kabalci E.,University of Nevsehir
Applied Energy | Year: 2011

The solar energy becomes a challenging area among other renewable sources since the solar energy sources have the advantages of not causing pollution, having low maintenance cost, and not producing noise due to the absence of the moving parts. Although these advantages, the installation cost of a solar power plant is considerably high. However, feasibility analyses have a great role before installation in order to determine the most appropriate power plant site. Despite there are many methods used in feasibility analysis, this paper is focused on a new intelligent method based on an agglomerative hierarchical clustering approach. The solar irradiation and insolation parameters of Central Anatolian Region of Turkey are evaluated utilizing the intelligent feasibility analysis tool developed in this study. The clustering operation in the tool is performed by using the nearest neighbor algorithm. At the stage of determining the optimum hierarchical clustering results, Euclidean, Manhattan and Minkowski distance metrics are adapted to the tool. The achieved clustering results based on Minkowski distance metric provide the most feasible inferences to knowledge domain expert according to other distance metrics. © 2011 Elsevier Ltd.

Sahinkaya S.,University of Nevsehir
Journal of Industrial and Engineering Chemistry | Year: 2013

Combination of electro-Fenton (EF) oxidation process with sonication for both the degradation of C.I. Reactive Black 5 (RB 5) and removal of chemical oxygen demand (COD) from synthetic textile wastewater was investigated under different operating conditions. Optimal conditions were found as the initial pH of 3, DC current of 0.25A, H2O2 dosage of 800mg/L and electrode distance of 2.5cm for both EF and ultrasound assisted electro-Fenton (sono-EF) processes. However, the combination of EF with sonication was negligibly improved in terms of COD and color removals, compared to EF process. © 2012 The Korean Society of Industrial and Engineering Chemistry.

Kum H.,University of Nevsehir
International Journal of Energy Economics and Policy | Year: 2012

This paper examines the unit root properties of energy consumption per capita for 15 East Asia & Pacific countries employing the Lagrange Multiplier (LM) panel unit root test with one structural break for 1971-2007. When we apply the LM univariate test without break, we find a unit root in per capita consumption for Brunei Darussalam, Indonesia, Japan, North Korea, South Korea and Myanmar. However, when we apply LM unit root with structural break, we find overwhelming evidence that there is no unit root in per capita energy consumption for these 15 East Asia & Pacific countries.

Kabalci E.,University of Nevsehir
Energy Conversion and Management | Year: 2013

A hybrid renewable energy plant that is based on solar and wind energy conversion systems is designed and analysed in this paper. Each separate energy conversion system is controlled either using regular PI controller or extended PI controller with an auxiliary controller containing Perturb and Observe algorithm. The solar plant model is constituted by connecting 170 W photovoltaic (PV) panels serially and energy conversion is performed with maximum power point tracking (MPPT) algorithm that controls the modulator of buck converter. The MPPT algorithm utilized in the control step of converter is developed using Perturb and Observe (P&O) that is extended with PI controller. The wind energy plant is designed with a permanent magnet synchronous generator (PMSG), and the AC-DC conversion stage is constituted with an uncontrolled full-bridge rectifier. All the converter outputs are connected to a busbar over interphase transformers (IPTs). The DC bus-bar voltage is supplied to a full bridge inverter to generate three-phase AC voltages at the output of inverter. The three-phase inverter is controlled with sinusoidal pulse width modulation (SPWM) scheme, which is developed with phase shifted carrier signals. The total harmonic distortion (THD) ratios are obtained at proper values according to international standards such as IEC61000 and IEEE 519-1992. Measurement results and obtained three phase voltage are analysed in detail. © 2013 Elsevier Ltd. All rights reserved.

Sahinkaya S.,University of Nevsehir
Process Safety and Environmental Protection | Year: 2015

The individual and simultaneous effects of acid and ultrasonic pretreatment on the disintegration of municipal waste activated sludge (WAS) were investigated based on chemical properties of WAS. In the combination of acid and ultrasonic pretreatment methods (ultrasonic-acid pretreatment), lowering pH accelerated and enhanced the disintegration of waste biological sludge. Therefore, the same disintegration efficiency (obtained by ultrasonic pretreatment alone) was achieved by the combined pretreatment in shorter sonication times. Optimum pretreatment conditions were ultrasonic power density of 1.0 W/mL and pretreatment time of 10 min for ultrasonic pretreatment alone, and ultrasonic power density of 1.0 W/mL, pretreatment time of 10 min and initial sludge pH of 2.0 for the combined pretreatment. Sludge disintegration degrees were about 30% and 40% under these optimized conditions, respectively. Optimum sludge concentration was found to be 1.0% total solid (TS) content for the combined pretreatment. As a result, ultrasonic-acid pretreatment has been determined as a new and effective combined sludge pretreatment method to improve the sludge disintegration. © 2013 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Bayrak G.,University of Nevsehir
Energy Conversion and Management | Year: 2015

This study presents a new remote islanding detection method and control system for photovoltaic (PV) based Distributed Generation (DG) systems. The proposed method monitors and controls the grid, local load and the output of the PV inverter in real time with the communication of circuit breakers. The proposed remote control system detects the changes in the currents of the circuit breakers, frequency, and the voltages by checking the defined threshold values at all electrical branches of the PV system. The proposed islanding detection algorithm was implemented by a low-cost FPGA board. The control system was also designed by considering a Very Large Scale Integration (VLSI) structure. The proposed method was verified by a developed prototype PV system constituted in the laboratory. The proposed control system was checked in a resonance condition with an active power match, and the verified results indicated that the developed system was also independent of the load and the inverter. Islanding detection time is approximately 1.65 ms even in a worst-case operational scenario, and this is a significantly shorter response time according to the existing standards. The proposed method presents a realistic solution to islanding, is easy to implement, and is suitable for real system applications. The method also provides a reliable islanding detection and presents a low-cost solution to the subject. © 2015 Elsevier Ltd.All rights reserved.

Kabalci E.,University of Nevsehir
Energy Conversion and Management | Year: 2015

The automatic meter reading is essentially required in renewable grids as in conventional grids. It is intended to propose a reliable measurement system that is validated in a photovoltaic power system to meet the requirement of a renewable grid. In the presented study, the photovoltaic plants are controlled by using a widely known maximum power point tracking algorithm that is named as "Perturb and Observe". The distribution line at the output of inverter is modelled according to realistic parameters of 25 km line. Besides carrying the generated line voltage, the grid is used as a transmission medium for the generated power measurements of photovoltaic plants and power consumptions of load plants separately. The modem constituting the power line communication manages the dual-channel transfer and transmits the consumed energy ratios of the load plants. One of the modems is located at the output of voltage source inverter and the other one of the load plants. The power consumption values of each load plants are individually measured and successfully transmitted to monitoring section in the modelled system. The obtained data that is only used for monitoring in this application can also be evaluated for automatic meter reading applications. © 2014 Elsevier Ltd. All rights reserved.

Ocal O.,University of Nevsehir | Aslan A.,University of Nevsehir
Renewable and Sustainable Energy Reviews | Year: 2013

This paper examines the renewable energy consumption-economic growth causality nexus in Turkey. Studies in the literature can be grouped as country-specific and multi-country studies. The results of these studies are inconsistent, and there is no agreement on the existence or the direction of causality between renewable energy consumption and economic growth. The results of this country-specific study support conservation hypothesis. The results of empirical tests from ARDL approach show that renewable energy consumption has a negative impact on economic growth, and the ones of Toda-Yamamoto causality tests show that there is a unidirectional causality running from economic growth to renewable energy consumption. © 2013 Elsevier Ltd. All rights reserved.

Kervan N.,University of Nevsehir
Journal of Magnetism and Magnetic Materials | Year: 2012

The electronic structure and magnetic properties of the Heusler compound Co 2ScP have been investigated by the generalized gradient approximation based on density functional theory. The results show that the ground state phase of the Co 2ScP compound possesses AlCu 2Mn-type crystal structure and exhibits half-metallic ferrimagnetism. The total spin moment is 2 μ B at the equilibrium lattice constant a 0=5.83 Å, which agrees with the Slater-Pauling rule. The spin-up electrons are metallic, but the spin-down bands are semiconductor with a gap of 0.55 eV, and the spin-flip gap is of 0.07 eV. © 2012 Elsevier B.V. All rights reserved.

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