The Eastern Mediterranean University , located in Northern Cyprus, was established in 1979 under the leadership of Onay Fadıl Demirciler as a higher-education institution of technology for Turkish Cypriots. In 1986, it was converted to a state university. The campus is located 10 km from the city of Famagusta.The university has 139 programs offering undergraduate and postgraduate degrees, as well as a research infrastructure. The medium of instructions are in Turkish and English. However, English Preparatory School is available for students who need to improve their English. The university offers variety of sports and social activities. Academic Programs of EMU are broad and include Physical and Social science with considerable research studies via Research Advisory Board. Wikipedia.
Komurcugil H.,Eastern Mediterranean University
ISA Transactions | Year: 2012
This paper presents an adaptive terminal sliding mode control (ATSMC) strategy for DC-DC buck converters. The idea behind this strategy is to use the terminal sliding mode control (TSMC) approach to assure finite time convergence of the output voltage error to the equilibrium point and integrate an adaptive law to the TSMC strategy so as to achieve a dynamic sliding line during the load variations. In addition, the influence of the controller parameters on the performance of closed-loop system is investigated. It is observed that the start up response of the output voltage becomes faster with increasing value of the fractional power used in the sliding function. On the other hand, the transient response of the output voltage, caused by the step change in the load, becomes faster with decreasing the value of the fractional power. Therefore, the value of fractional power is to be chosen to make a compromise between start up and transient responses of the converter. Performance of the proposed ATSMC strategy has been tested through computer simulations and experiments. The simulation results of the proposed ATSMC strategy are compared with the conventional SMC and TSMC strategies. It is shown that the ATSMC exhibits a considerable improvement in terms of a faster output voltage response during load changes. © 2012 ISA.
Amirabi Z.,Eastern Mediterranean University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013
We revisit the spherically symmetric third order Lovelock black hole solution in seven dimensions. We show that the general solution for the metric function does not admit the Gauss-Bonnet (GB) limit. This is not expected due to the linear superposition of the second (GB) and third order Lovelock Lagrangians in the general action. It is found that the two branches of the GB solutions are indeed the limit of the other two complex solutions of the field equations in the third order Lovelock gravity. These two complex solutions could not be accepted as the solutions of Einstein's field equations which are supposed to be real value functions on the entire real r axis. A new solution, which is valid only if the third order Lovelock parameter is small, is introduced which can be considered as the natural extension of general relativity to the third order Lovelock modified theory of gravity. We also generalize the discussion to the higher dimensional third order Lovelock gravity coupled to matter sources with a cosmological constant. © 2013 American Physical Society.
Komurcugil H.,Eastern Mediterranean University
IEEE Transactions on Industrial Electronics | Year: 2012
A new method to the sliding-mode control of single-phase uninterruptible-power-supply inverters is introduced. The main idea behind this new method is to utilize a time-varying slope in the sliding surface function. It is shown that the sliding line with the time-varying slope can be rotated in the phase plane in such a direction that the tracking time of the output voltage is improved during load variations. The adjustment of the time-varying slope is achieved dynamically by employing a simple function which involves the error variables of the system. This function is obtained from the input/output relationship of the single-input fuzzy logic controller operating on the error variables. When a newly computed slope value is applied to the system, the position of the representative point is changed so as to achieve the desired response. The performance of the proposed control method has been tested through computer simulations and experiments using a triac-controlled resistive load and a diode bridge rectifier load. The results of the proposed method are compared with a classical sliding mode controller and a standard controller. It has been shown that the proposed method is capable of shortening the tracking and sliding times, resulting in a smaller total harmonic distortion in the output voltage. © 2012 IEEE.
Atikol U.,Eastern Mediterranean University
Energy | Year: 2013
In many developing countries due to lack of infrastructure the utilities experience difficulties in monitoring their customers' demand or time of use of electricity and hence it is very difficult to apply DSM (demand-side management) programs for peak shifting. In several of these countries the residential EWHs (electric water heaters) are usually responsible for the evening peak. The general attitude of people is to turn them on just before they need hot water and statistics have shown that this takes place in the evening hours constituting the evening peak. The present work reviews the experimental findings about the static and dynamic cooling behavior of hot water in storage tanks and discusses the possible timer programs to avoid the peak hours. It is deduced from the experiments that even when the hot water is kept standing in a tank for 12h after the initial withdrawal of 64.2L, it would be possible to have warm water at temperatures above 40°C in the top 15% of the tank to utilize. If the DSM programs are carefully designed it would be possible to set the timers to operate the EWHs for once or twice a day to meet the daily demand of households. © 2013 Elsevier Ltd.
Kamali S.,Eastern Mediterranean University
Energy and Buildings | Year: 2014
Buildings are responsible for 40% of our nation's total annual energy consumption and for one-third of our greenhouse gas emissions. These greenhouse gases are the cause of global warming. Lighting, heating, cooling, and air conditioning are all heavy energy consumers. Interestingly, advances in the understanding of the environmental effects of greenhouse gas emissions have led to a rise in the use of environmentally friendly cooling and heating systems in buildings. Free cooling systems rely on phase change materials that absorb heat from indoors during the day and then release it outdoors during the night. The investigations undertake by different researchers will be explained in this article. Phase change materials, climate applicability, feasibility analysis, and factors affecting the charging and discharging are discussed briefly. The reduction in CO2 emissions resulting from the application of free cooling systems to buildings is also discussed. © 2014 Elsevier B.V.