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Ankara, Turkey

Atılım University is a private university founded in 1996. It is located in Ankara, the capital of Turkey. The language of instruction for most courses is English. Education programs are at international standards .The University of the Incarnate Word in San Antonio, Texas is the sister university of Atılım, and 6 European universities in France, the Netherlands, Poland and Spain in accordance with the student exchange program. Also, it is among the Erasmus University Charter universities. Wikipedia.

Eryilmaz S.,Atilim University
IEEE Transactions on Reliability

A κ - out - of - ν : G system consists of n components, and operates if at least κ of its components operate. Its reliability properties have been widely studied in the literature from different perspectives. This paper is concerned with the reliability analysis of a κ - out - of - ν : G system equipped with a single warm standby unit. We obtain an explicit expression for the reliability function of the system for arbitrary lifetime distributions. Two different mean residual life functions are also studied for the system. © 2012 IEEE. Source

Sulfonated polyphenyl sulfone/phosphotungstic acid/silica (sPPS/PWA/silica) hybrid membranes were prepared and characterized as alternative materials for PEMFC operation at high temperature and low humidity conditions. Polyphenyl sulfone polymer (PPS) was sulfonated with trimethylsilyl chlorosulfonate in 1,2 dichloroethane at ambient temperatures. The degree of sulfonation was determined by 1H-NMR analysis. Sulfonation levels from 25 to 45% were easily achieved by varying the content of the sulfonation agent. The hybrid membrane was composed of the mixture of sPPS solution, PWA/silica particles. The structures of the membranes were investigated by Scanning Electron Microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and by thermogravimetric analysis (TGA). The composite membranes gained good thermal resistance with insertion of PWA/silica. SEM results have proven the uniform and homogeneous distribution of PWA/silica in hybrid membrane. The existence PWA/silica has improved the water uptake, proton conductivity and oxidative stability of hybrid membrane. Gas diffusion electrodes (GDE) were fabricated by ultrasonic coating technique. Catalyst loading was 0.4 mg Pt/cm2 for both anode and cathode sides. The membranes were tested in a single cell with a 5 cm2 active area operating at the temperature range of 70 to 120°C and 100 and 30% relative humidity conditions. Single PEMFC tests performed at different operating temperatures indicated that sPPS/PWA/silica hybrid membrane was more stable and also performed better than pristine sPPS membrane. At the overall, the sPPS/PWA/silica hybrid membrane seems to be a promising alternative membrane for the possible utilization in PEMFC. © 2014 Elsevier Ltd. All rights reserved. Source

A criterion for the global asymptotic stability of fixed-point state-space digital filters using two's complement arithmetic is presented. The criterion is a modified form of a well-known criterion due to Mills, Mullis, and Roberts. The criterion is in the form of linear matrix inequality and, hence, computationally tractable. An example shows the effectiveness of the modified criterion. © 2009 Elsevier Ltd. All rights reserved. Source

Melikoglu M.,Atilim University
Renewable and Sustainable Energy Reviews

Turkey is a recently developed country, a regional power in the Middle East and an economic powerhouse of the region. Turkey's electricity demand is continuously increasing due to fast economic growth coupled with the country's vibrant young population. It is envisaged that this demand would keep on increasing almost exponentially in the next decade according to the recently avowed Vision 2023 agenda. According to which, the Turkish government ambitiously wants to provide 30.0% of the country's electricity demand from renewable energy sources by 2023. Turkey has vast renewable energy potential including hydro, geothermal, solar and wind. However, historically there is only one playmaker that is hydropower. Thus a detailed review of the current status and future prospects of Turkish hydropower market is urgently needed to generate a roadmap for the Vision 2023 agenda. This paper was intended to provide that vital information. Currently, more than 25.0% or 57.5 TWh of the country's electricity demand is supplied from hydropower. According to official projections this would increase to approximately 116.0 TWh in 2023. In this study, hydropower's supply rate of Turkey's annual electricity demand was assessed based on the official projections and a forecast was generated. Results showed that between 22.0% and 27.0% of Turkey's annual electricity demand should be supplied from hydropower in 2023. Therefore, between 22.5 TWh and 45.0 TWh of electricity should be generated from renewable energy sources other than hydropower to provide a total of 30.0% renewable energy based electricity generation in 2023. © 2013 Elsevier Ltd. Source

Melikoglu M.,Atilim University
Renewable and Sustainable Energy Reviews

Natural gas is the primary source for electricity production in Turkey. However, Turkey does not have indigenous resources and imports more than 98.0% of the natural gas it consumes. In 2011, more than 20.0% of Turkey's annual trade deficit was due to imported natural gas, estimated at US$ 20.0 billion. Turkish government has very ambitious targets for the country's energy sector in the next decade according to the Vision 2023 agenda. Previously, we have estimated that Turkey's annual electricity demand would be 530,000 GWh at the year 2023. Considering current energy market dynamics it is almost evident that a substantial amount of this demand would be supplied from natural gas. However, meticulous analysis of the Vision 2023 goals clearly showed that the information about the natural gas sector is scarce. Most importantly there is no demand forecast for natural gas in the Vision 2023 agenda. Therefore, in this study the aim was to generate accurate forecasts for Turkey's natural gas demand between 2013 and 2030. For this purpose, two semi-empirical models based on econometrics, gross domestic product (GDP) at purchasing power parity (PPP) per capita, and demographics, population change, were developed. The logistic equation, which can be used for long term natural gas demand forecasting, and the linear equation, which can be used for medium term demand forecasting, fitted to the timeline series almost seamlessly. In addition, these two models provided reasonable fits according to the mean absolute percentage error, MAPE %, criteria. Turkey's natural gas demand at the year 2030 was calculated as 76.8 billion m3 using the linear model and 83.8 billion m3 based on the logistic model. Consequently, found to be in better agreement with the official Turkish petroleum pipeline corporation (BOTAS) forecast, 76.4 billion m3, than results published in the literature. © 2013 Published by Elsevier Ltd. Source

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