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Öğe Analysis of Magnetization Properties of the Ferromagnetic Granular Beds(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2016) Abbasov, Teymuraz; Herdem, SaadetdinMagnetization properties of the packed beds that are constructed from ferromagnetic balls and metal chips have been examined. The average magnetic permeability and magnetization curves of the non-homogeneous ferromagnetic granulated medium (different size polyballs and chips) have been determined using the channel-by-channel magnetization model. From the magnetic properties of the single chain of the different sized balls as an element of the chain bundle in the polyball medium, application conditions of the model to the polyball medium were estimated. A new correlation for the influence of the packing density factor or the bed porosity change on the average magnetization curve has been evaluated. A new correlation between the packing density factor and the size of the bed elements, and also a relationship between the relative magnetic permeability of the bed elements and the external magnetic field intensity were obtained. The obtained theoretical results were compared with statistical data and an agreement was observed.Öğe Analysis of spectral features of mechanical heart valve sounds after aortic and mitral valve replacement(2010) Altunkaya, Sabri; Kara, Sadık; Görmüş, Niyazi; Herdem, SaadetdinMechanical heart valves are a substitute for malfunctional native heart valves. In this study, the spectral features of S1 and S2 component of the mechanical heart valve sounds obtained after aortic valve replacement (AVR) and mitral valve replacement (MVR) are compared. For this aim, AR methods are applied on the S1 and S2 components of heart sounds taken from 68 recording of 8 patients with AVR and 87 recordings from 11 patients with MVR, thereby yielding power spectrum of the heart sound and six different features are obtained from power spectrum of the heart sounds. Using these features, S1 and S2 components are compared. ©2010 IEEE.Öğe Bulanık mantık yöntemiyle manyetik filtrelerin kontrolü(Selçuk Üniversitesi Teknik Bilimler Meslek Yüksekokulu, 2009) Sarıtaş, İsmail; Herdem, SaadetdinBu çalışmada; teknolojik sıvıların içersinde bulunan mikron ve submikron boyutlarındaki manyetik özellikli parçacıkların temizlenmesi için bir manyetik filtre (MF) tasarlanmıştır. Teknolojik sıvının temizlenmesi yanında filtre matrisinin temizlenmesini sağlayan iki adet MF kullanılarak bulanık kontrol sistemi gerçekleştirilmiştir. Bu kontrol ile filtre matrisi içerisinden geçen manyetik özellikli parçacıkların miktarı ve teknolojik sıvının akış hızı değişimine bağlı olarak filtre bobininin akımı dolayısıyla MF’nin manyetik akısı da değiştirilmektedir. Böylece Mf’nin performansı optimum olarak kontrol edilebilmektedir. Ayrıca filtrenin performansı düştüğünde filtre matrisinin temizlenmesi sağlanarak aynı filtre matrisinin tekrar tekrar kullanımına olanak sağlamaktadır. Bu çalışma ile yapılan kontrol sistemi MF’lerin yüksek performansla çalışmalarını, gereksiz enerji kullanılmasını önlediği için enerji tasarrufunu, dolayısıyla ekonomik kazancı da sağlamaktadır.Öğe Comparison of first and second heart sounds after mechanical heart valve replacement(TAYLOR & FRANCIS LTD, 2013) Altunkaya, Sabri; Kara, Sadik; Gormus, Niyazi; Herdem, SaadetdinIn this article, the spectral features of first heart sounds (S1) and second heart sounds (S2), which comprise the mechanical heart valve sounds obtained after aortic valve replacement (AVR) and mitral valve replacement (MVR), are compared to find out the effect of mechanical heart valve replacement and recording area on S1 and S2. For this aim, the Welch method and the autoregressive (AR) method are applied on the S1 and S2 taken from 66 recordings of 8 patients with AVR and 98 recordings from 11 patients with MVR, thereby yielding power spectrum of the heart sounds. Three features relating to frequency of heart sounds and three features relating to energy of heart sounds are obtained. Results show that in comparison to natural heart valves, mechanical heart valves contain higher frequency components and energy, and energy and frequency components do not show common behaviour for either AVR or MVR depending on the recording areas. Aside from the frequency content and energy of the sound generated by mechanical heart valves being affected by the structure of the lungsthorax and the recording areas, the pressure across the valve incurred during AVR or MVR is a significant factor in determining the frequency and energy levels of the valve sound produced. Though studies on native heart sounds as a non-invasive diagnostic method has been done for many years, it is observed that studies on mechanical heart valves sounds are limited. The results of this paper will contribute to other studies on using a non-invasive method for assessing the mechanical heart valve sounds.Öğe The control of magnetic filters by FPGA based fuzzy controller(SILA SCIENCE, 2012) Ozkan, Ilker Ali; Saritas, Ismail; Herdem, SaadetdinOne of the most effective methods to clean magnetic particles in industrial liquids is magnetic filtration. Magnetic filters (MF) are being used increasingly since they can work under various conditions like high temperature and radioactivity. However, there are many factors like particle concentration and flow speed that affect magnetic filter performance (MFP). In this study, a portable, compact MF kit that cleans micron-sized magnetic particles and is suitable for industrial purposes was designed and realized. A FPGA based fuzzy control system that considers the factors which influence MF performance was developed and integrated with MF kit. With this control system both the MF performance is kept at maximum and MF can clean itself. Thus, besides an effective filtration process which increases quality, sustainability of production and energy save is achieved.Öğe The effects of fuzzy control of magnetic flux on magnetic filter performance and energy consumption(PERGAMON-ELSEVIER SCIENCE LTD, 2010) Saritas, Ismail; Ozkan, Ilker Ali; Herdem, SaadetdinMagnetic filters are used effectively in many industrial areas to clean up technological liquids and gases from micron and submicron size magnetic particles. Performance of the magnetic filter is affected by technological parameters like flow rate of the industrial liquid and concentration and flux magnitude of the magnetic filter. These parameters exhibit differences depending on the field of work. Controlling of magnetic filters without regard to these parameters has disadvantages such as low filter performance, ineffectiveness in parameter changes and high energy consumption. To remove these disadvantages, an adaptive fuzzy control system which considers these technological parameters was designed and realized. When the realized filter is compared to the filter that ignores technological parameters, it is observed that energy can be saved at a rate of 68% annually. (C) 2010 Elsevier Ltd. All rights reserved.Öğe FPGA-based self-organizing fuzzy controller for electromagnetic filter(SPRINGER, 2017) Ozkan, Ilker Ali; Herdem, Saadetdin; Saritas, IsmailElectromagnetic filters (EMF) are used to clean magnetic particles in industrial liquids which play important roles to sustain the high-quality material production in industrial fields. In this study, an FPGA-based adaptive fuzzy controller is realized to sustain high performance of an EMF. An experiment is performed by using realized adaptive controller on an EMF set. The results obtained from the experiment are compared with the results of the conventional fuzzy controller. It is observed that adaptive fuzzy controller is performed better than the conventional fuzzy controller.Öğe Manyetik filtreler için FPGA tabanlı bulanık kontrolör tasarımı(Selçuk Üniversitesi Teknik Bilimler Meslek Yüksekokulu, 2011) Özkan, İlker Ali; Sarıtaş, İsmail; Herdem, SaadetdinFPGA'ler işlemleri yüksek hızda ve paralel olarak gerçekleştirebilen, veri depolama kapasiteli, taşınabilir, pratik, az miktarda enerji harcayan, programlanabilen lojik cihazlardır. Bu özellikleri FGPA'leri güçlü bir dijital kontrol aracı haline de getirmektedir. Bu çalışmada Manyetik Filtre (MF) performansını en yüksek seviyede tutacak bir bulanık mantık kontrolör tasarımı VHDL kullanılarak FPGA üzerinde gerçekleştirilmiştir. Gerçekleştirilen modelin test sonuçları ile MATLAB&Fuzzy Logic Toolbox'dan elde edilen test sonuçları karşılaştırılarak kontrol sisteminin doğrulaması yapılmıştır. Diğer sistemlere göre önerilen sistemin dikkate değer şekilde başarılı olduğu görülmüştür.Öğe Statistically Evaluation of Mechanical Heart Valve Thrombosis Using Heart Sounds(INT ASSOC ENGINEERS-IAENG, 2010) Altunkaya, Sabri; Kara, Sadık; Görmüş, Niyazi; Herdem, SaadetdinThrombosis is a serious complication and important cause of mortality and morbidity reason for patients with mechanical heart valve. Echocardiogram of mechanical heart valves is necessary to diagnose valve thrombosis definitely. Because of the difficulty in making early diagnosis of thrombosis, and the cost of diagnosis equipment and operators, improving noninvasive, cheap and simple methods to evaluate the functionality of mechanical heart valves are quite significant. In this study, statistical features obtained from auscultation of heart sounds are proposed to evaluate mechanical heart valve thrombosis as a simple method. For this aim, heart sounds of one patient with mechanical heart valve thrombosis and five patients with normally functioning mechanical heart valve were recorded. Statistical features of these sounds, the skewness and kurtosis, were calculated and statistically evaluated using t-test. As a result, it is clearly seen that the skewness of Si sounds is the most discriminative features (p < 0.01) and it may be used fairly well in differentiating normally functioning mechanical heart valve from malfunctioning mechanical heart valve.Öğe Time domain features of heart sounds for determining mechanical valve thrombosis(2011) Altunkaya, Sabri; Kara, Sadık; Görmüş, Niyazi; Herdem, SaadetdinThrombosis of implanted heart valve is a rare but lethal complication for patients with mechanical heart valve. Echocardiogram of mechanical heart valves is necessary to diagnose valve thrombosis definitely. Because of the difficulty in making early diagnosis of thrombosis, and the cost of diagnosis equipment and operators, improving noninvasive, cheap and simple methods to evaluate the functionality of mechanical heart valves are quite significant especially for first step medical center. Because of this, time domain features obtained from auscultation of heart sounds are proposed to evaluate mechanical heart valve thrombosis as a simple method in this chapter. For this aim, heart sounds of one patient with mechanical heart valve thrombosis and five patients with normally functioning mechanical heart valve were recorded. Time domain features of recorded heart sounds, the skewness and kurtosis, were calculated and statistically evaluated using paired and unpaired t-test. As a result, it is clearly seen that the skewness of first heart sound is the most discriminative features (p < 0.01) and it may be used fairly well in differentiating normally functioning mechanical heart valve from malfunctioning mechanical heart valve. © 2011 Springer Science+Business Media B.V.
