TR-Dizin İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/396
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Article Thermal Stresses in SOFC Stacks: The Role of Mismatch Among Thermal Conductivity of Adjacent Components(Tubitak Scientific & Technological Research Council Turkey, 2021-06-30) Aydin, Ozgur; Matsumoto, Go; Shiratori, YusukeGenerating power from renewable biogas in solid oxide fuel cells (SOFCs) is an environment-friendly, efficient, and promising energy conversion process. Biogas can be used in SOFCs via a reforming process for which dry reforming is more suitable as the reforming agent exists in the biogas mixture. Biogas can be directly reformed to H-2 -rich fuel stream in the anode chamber of a SOFC by the heat released during power generation. Exploiting the heat and water produced in the SOFC for internal reforming of biogas makes the energy conversion process very efficient; however, various challenges are reported. Thus, indirect internal reforming is opted for which a separate reforming domain is required. In an indirect internal reformer operating at usual conditions, dry reforming rate is quite high in the inlet and it decreases steeply toward the fuel outlet. Great temperature gradients develop over the reformer, since the dry reforming reaction is strongly endothermic. The abruptly varying rate of the reforming reaction affects the temperature fields in the adjacent components of SOFC and hence intolerable thermal stresses emerge on the SOFC components. In our preceding study, we graded the reforming domain, homogenized the temperature profile over the reforming domain, and executed performance and durability experiments. However, most of the experiments failed due to fracturing SOFC components hinting at existence of thermal stresses. In that study, we focused on minimizing the temperature gradients within the reforming domain; namely, we neglected the other processes. To eliminate the thermal stresses, we modeled the entire module of SOFC equipped with a reformer featuring a graded reforming domain. We found that the mismatch between the thermal conductivities of the adjacent module components is the major reason for the thermal stresses. When the mismatch is eliminated, thermal stresses disappear even if the reforming domain is not graded.Article Citation - WoS: 4Citation - Scopus: 5Noise-Assisted Multivariate Empirical Mode Decomposition Based Emotion Recognition(Istanbul Univ-Cerrahapasa, 2018-08-03) Ozel, Pinar; Akan, Aydin; Yilmaz, BulentEmotion state detection or emotion recognition cuts across different disciplines because of the many parameters that embrace the brain's complex neural structure, signal processing methods, and pattern recognition algorithms. Currently, in addition to classical time-frequency methods, emotional state data have been processed via data-driven methods such as empirical mode decomposition (EMD). Despite its various benefits, EMD has several drawbacks: it is intended for univariate data; it is prone to mode mixing; and the number of local extrema must be enough before the EMD process can begin. To overcome these problems, this study employs a multivariate EMD and its noise-assisted version in the emotional state classification of electroencephalogram signals. Emotion state detection or emotion recognition cuts across different disciplines because of the many parameters that embrace the brain's complex neural structure, signal processing methods, and pattern recognition algorithms. Currently, in addition to classical time-frequency methods, emotional state data have been processed via data-driven methods such as empirical mode decomposition (EMD). Despite its various benefits, EMD has several drawbacks: it is intended for univariate data; it is prone to mode mixing; and the number of local extrema must be enough before the EMD process can begin. To overcome these problems, this study employs a multivariate EMD and its noise-assisted version in the emotional state classification of electroencephalogram signals.Article Citation - WoS: 1Citation - Scopus: 5Understanding Intangible Aspects of Cultural Landscape; Living Cultures of Northeast Kayseri Valleys(Geleneksel Yayincilik Ltd Stl, 2021) Kevseroglu, Oztem; Ayatac, Hatice; Yoney, Nilufer Baturayoglu; Baturayoğlu Yöney, NilüferSustaining cultural landscapes requires the conservation of socio-cultural characteristics as well as their physical manifestations. It is essential to document and conserve tangible and intangible elements of heritage in an integrated manner as cultural heritage consists of "both tangible and intangible works through which the creativity of a people finds expressions". These include but may not be limited to social practices, daily lives, rituals, traditional craftsmanship, know-how, techniques and skills, historic places, buildings, public spaces and objects. Finding the means of understanding and safeguarding intangible cultural heritage and its transmission to next generations is vital for the preservation of tangible heritage and its characteristics. This paper reviews the development of the concepts of intangible cultural heritage and cultural landscapes, and the interrelationship between tangible and intangible cultural heritage. Their interaction opens up new approaches to cultural heritage and its conservation. The case study focuses on the cultural landscape features of Kayseri's Northeast Valleys, Koramaz, Gesi and Derevenk, in terms of their tangible and intangible heritage elements and values. The methodology, therefore, proposes the integrated documentation and analysis of these tangible and intangible cultural heritage characteristics. The area had a multi-cultural, ethnic and religious social structure, which shaped its elements through human-nature interaction. However, demographic changes within the last century transformed daily-life practices. The research is based on in-depth interviews with local residents, analysis of archival sources and documentation of the physical remains in the field. The results highlight the traditional crafts and production techniques as daily-life practices; some of these are still continued at the present while others are not practiced anymore. Those practiced in the recent past are carried to our day through the remembrances and accounts of the elders. The documentation of these practices forms the first step for their revival and sustainability for the future and provide valuable tools for the development of principles and strategies with this purpose. Understanding the physical, natural and socio+ layers of tangible and intangible cultural heritage is essential in this context. Their promotion and the inclusion of local stakeholders in the conservation process is the only solution for the integrated conservation of these cultural landscapes in terms of a living heritage approach.