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Öğe Experimental investigation of solar stills integrated with solar water heating collectors(Türk Isı Bilimi ve Tekniği Derneği, 2017-10-31) Argunhan, Zeki; El, Emin; Yıldız, Cengiz; Çakmak, GülşahSolar still is a more practical way of obtaining clean water. In this study, we aimed to improve the efficiency of solar still systems and obtain distilled water at the same time. For this purpose, 5 different solar still systems were designed. Type 1; conventional solar still, Type 2; conventional solar still integrated with solar water heating collector and run via natural convection, Type 3; conventional solar still integrated with solar water heating collector and tubular heat exchanger and run via natural convection, Type 4; conventional solar still placed with plate heat exchanger and integrated with solar water heating collector and run via natural convection, Type 5; conventional solar still placed with plate heat exchanger and integrated with solar water heating collector and run via forced convection. In this study, the experiments were carried out on the parameters influencing the performance, the amount of distilled water obtained, and the efficiency of experiment settings designed in different types; and finally the results were presented. The amount of distilled water and efficiency of conventional solar still were 2389 ml and 51.47%, respectively. Maximum total amount of water and efficiency from natural convection systems were obtained from Type 4, and the values calculated were found as to be 5788 ml and 55.91%. Maximum amount of distilled water and the efficiency were obtained by utilizing forced convection system were found as to be 6068 ml and 58.99%, respectively.Öğe A novel approach for extracting ideal exemplars by clustering for massive time-ordered datasets(TÜBİTAK, 2017-07-30) Ertuğrul, Ömer FarukThe number and length of massive datasets have increased day by day and this yields more complex machine learning stages due to the high computational costs. To decrease the computational cost many methods were proposed in the literature such as data condensing, feature selection, and filtering. Although clustering methods are generally employed to divide samples into groups, another way of data condensing is by determining ideal exemplars (or prototypes), which can be used instead of the whole dataset. In this study, first the efficiency of traditional data condensing by clustering approach was confirmed according to obtained accuracies and condensing ratios in 9 different synthetic or real batch datasets. This approach was then improved to be employed in time-ordered datasets. In order to validate the proposed approach, 23 different real time-ordered datasets were used in experiments. Achieved mean RMSEs were 0.27 and 0.29 by employing the condensed (mean condensed ratio was 97.17%) and the whole datasets, respectively. Obtained results showed that higher accuracy rates and condensing ratios were achieved by the proposed approach.Öğe Effect of the air flow rate of blower on the performance of solar still(Türk Isı Bilimi ve Tekniği Derneği, 2015-06-01) Argunhan, Zeki; El, Emin; Yücel, Halit Lutfi; Çakmak, Gülşah; Yıldız, CengizSolar distillation is one of the important methods for water purification. This paper examines the performance of solar distillation system at different air flow rate. To increase the performance of distiller, artificial wind was created by fan and suitable wind speed was investigated to increase the amount of water distilled. The experiments were carried out in Elazığ climate conditions. In order to examine the effect of the wind speed on solar distillation system, two stills were manufactured with the size of 1000x1000 mm. One of them was the conventional still which was used as a reference. The other still was used to investigate experimentally the effect of the wind speed. Graphs were drawn for time-dependent changes in the amount of water distilled. It was found that that the productivity of the fan-still distiller was 14.7 % greater than that of a conventional still.Öğe A new record and three little-known Eupithecia Curtis species from Turkey (Lepidoptera: Geometridae)(TÜBİTAK, 2017-05-23) Seven, ErdemIn this paper, Eupithecia opistographata Dietze, 1906 is reported as new for the fauna of Turkey, and three rare species (E. brunneata Staudinger, 1900; E. dearmata Dietze, 1904; and E. marasa Wehrli, 1932) are presented as second records on the basis of specimens collected in the mountainous areas of Siirt Province and Şirvan District, southeastern Turkey. The adults and the male genitalia of the species are illustrated.Öğe A fast feature selection approach based on extreme learning machine and coefficient of variation(TÜBİTAK, 2017-07-30) Ertuğrul, Ömer Faruk; Tağluk, Mehmet EminFeature selection is the method of reducing the size of data without degrading their accuracy. In this study, we propose a novel feature selection approach, based on extreme learning machines (ELMs) and the coefficient of variation (CV). In the proposed approach, the most relevant features are identified by ranking each feature with the coefficient obtained through ELM divided by CV. The achieved accuracies and computational costs, obtained with the use of features selected via the proposed approach in 9 classification and 26 regression benchmark data sets, were compared to those obtained with all features, as well as those obtained with the features selected by a wrapper and a filtering method. The achieved accuracy values obtained with the proposed approach were generally higher than when using all features. Furthermore, high feature reduction ratios were obtained with the proposed approach, including the achieved feature reduction ratios in epilepsy, liver, EMG, shuttle, and abalone. Stock data sets were 90.48%, 90%, 70.59%, 66.67%, 75%, and 77.78%, respectively. This approach is an extremely fast process that is independent of the employed machine-learning methods.
