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Izmir, Turkey

Yaşar University is a university, in Izmir, Turkey on the Aegean Sea. The university faculty teaches in English, with programs at both the undergraduate and postgraduate level. Wikipedia.

The present study deals with modelling, analyzing and assessing the performance of greenhouse heating systems with earth-pipe-air heat exchangers (EAHEs) in closed loop mode. In this regard, an EAHE system is considered as an illustrative example. This system starts with the power plant, through the production of heat (EAHE), via a distribution system, to the heating system and from there, via the greenhouse air, across the greenhouse envelope to the outside environment. Exergy analysis method (the so-called low exergy or LowEx approach) has been and still being successfully used to design and evaluate sustainable buildings. It is applied to all components of this EAHE system for the first time to the best of the author's knowledge in this study. The overall energy efficiency value for the EAHE system studied is determined to be 72.10% while the overall exergy efficiency value is calculated to be 19.18% at a reference state temperature of 0 C. The exergy efficiency of the whole EAHE system decreases from 19.18% to 0.77% with the increase in the reference environment temperature from 0 to 18 C. The sustainability index values for the whole EAHE system decrease from 1.24 to 1.01 as the reference state temperature increases. © 2013 Elsevier B.V. Source

Hepbasli A.,Yasar University | Kecebas A.,Mugla University
Energy and Buildings | Year: 2013

This paper comparatively evaluates exergy destructions of a geothermal district heating system (GDHS) using both conventional and advanced exergetic analysis methods to identify the potential for improvement and the interactions among the components. As a real case study, the Afyon GDHS in Afyonkarahisar, Turkey, is considered based on actual operational data. For the first time, advanced exergetic analysis is applied to the GDHSs, in which the exergy destruction rate within each component is split into unavoidable/avoidable and endogenous/exogenous parts. The results indicate that the interconnections among all the components are not very strong. Thus, one should focus on how to reduce the internal inefficiency (destruction) rates of the components. The highest priority for improvement in the advanced exergetic analysis is in the re-injection pump (PM-IX), while it is the heat exchanger (HEX-III) in the conventional analysis. In addition, there is a substantial influence on the overall system as the total avoidable exergy destruction rate of the heat exchanger (HEX-V) has the highest value. On the overall system basis, the value for the conventional exergetic efficiency is determined to be 29.29% while that for the modified exergetic efficiency is calculated to be 34.46% through improving the overall components. © 2013 Elsevier B.V. Source

Tasdemir K.,Yasar University
IEEE Transactions on Neural Networks | Year: 2010

The self-organizing map (SOM) is a powerful method for manifold learning because of producing a 2-D spatially ordered quantization of a higher dimensional data space on a rigid lattice and adaptively determining optimal approximation of the (unknown) density distribution of the data. However, a postprocessing visualization scheme is often required to capture the data manifold. A recent visualization scheme CONNvis, which is shown effective for clustering, uses a topology representing graph that shows detailed local data distribution within receptive fields. This brief proposes that this graph representation can be adapted to show local distances. The proposed graphs of local density and local distances provide tools to analyze the correlation between these two information and to merge them in various ways to achieve an advanced visualization. The brief also gives comparisons for several synthetic data sets. © 2010 IEEE. Source

Atan T.,Yasar University
Biology of Sport | Year: 2013

For years, mostly the effects of music on cardiorespiratory exercise performance have been studied, but a few studies have examined the effect of music on anaerobic exercise. The purpose of this study was to assess the effect of listening to music and its rhythm on anaerobic exercise: on power output, heart rate and the concentration of blood lactate. 28 male subjects were required to visit the laboratory on 6 occasions, each separated by 48 hours. Firstly, each subject performed the Running-based Anaerobic Sprint Test (RAST) under 3 conditions on separate days: while listening to "slow rhythm music", "fast rhythm music" or "no music". 48 hours after the subjects completed RAST under 3 conditions, Wingate Anaerobic Power (WAN) tests were performed under 3 music conditions. The order of the 3 conditions (slow music, fast music and no music) was selected randomly to prevent an order effect. Results showed no significant differences between 3 conditions in anaerobic power assessments, heart rate or blood lactate (p>0.05). On the basis of these results it can be said that music cannot improve anaerobic performance. The type of music had no impact on power outputs during RAST and WAN exercise. As a conclusion, listening to music and its rhythm cannot enhance anaerobic performance and cannot change the physiological response to supramaximal exercise. Source

Kecebas A.,Mugla University | Hepbasli A.,Yasar University
Energy and Buildings | Year: 2014

The present study deals with analyzing, assessing and comparing conventional and advanced exergoeconomic analyses to identify the direction and potential for energy savings of a geothermal district heating system in future conditions/projections. As a real case study, the Afyon geothermal district heating system in Afyonkarahisar, Turkey, is considered while its actual operational thermal data on 8 February 2011 are utilized in the analysis, which is based on the specific exergy costing method. In this study for the first time, based on the concepts of avoidable/unavoidable and endogenous/exogenous parts, cost rates associated with both exergy destruction and capital investment of the geothermal district heating system are determined first, and the obtained results are then evaluated. The results indicate that the internal design changes play a more essential role in determining the cost of each component. The cost rate of unavoidable part within the components of the system is lower than that of the avoidable one. For the overall system, the value for the conventional exergoeconomic factor is determined to be 5.53% while that for the modified one is calculated to be 9.49%. As a result, the advanced exergoeconomic analysis makes more sense given the additional information in splitting process of the components. © 2013 Elsevier Ltd. All rights reserved. Source

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