Browsing by Author "Çelik, S."

Filter results by typing the first few letters
Now showing 1 - 5 of 5
  • Placeholder
    Project reportPublicationMetadata only
    2023'e doğru Türkiye'de üniversite kütüphaneleri mevcut durum, sorunlar, standartlar ve çözüm önerileri
    (2015-05-26) Çanak, T. A.; Çelik, S.; Çetinkaya, İ.; Çukadar, S.; Güneş, G.; Gürdal, G.; Holt, İlkay; Kaya, E.; Kaygusuz, A.; Library; HOLT, Ilkay
    Çağın gereklerine uygun ve dünya ile rekabet edebilir bir eğitim, öğretim ve araştırma altyapısı için üniversitelerin en azından kendi alanlarında üretilen bilgiye erişebilecek ve bu bilgiyi 7/24 kullanıcılarının hizmetine sunabilecek altyapıya sahip olmaları gerekir. Bu altyapıdan yoksun bir üniversitede dünyanın bilgi ve deneyiminden yeterince yararlanılamadığı ve hatta daha önce üretilmiş bilgi ve deneyimleri tekrar üretmek üzere gereksiz yere zaman ve para harcandığı ileri sürülebilir. Oysa dünyadaki söz sahibi üniversitelere bakıldığında, bu üniversitelerin kütüphanelerine ciddi yatırımlar yaptıkları ve bu yatırımların sürdürülebilir olması için gerekli önlemleri aldıkları görülür. Örnek vermek gerekirse; Avustralya ve Yeni Zelanda üniversite kütüphanelerinin kurum başına ortalama yayın alım bütçesi 9.386.523 dolar, en düşük yayın alım bütçesi ise 5.196.342 dolardır. American Research Library (ARL) üyesi olan Amerika ve Kanada üniversitelerinde kurum başına ortalama yayın alım bütçesi 10.388.129 dolar, en düşük yayın alım bütçesi ise 3.823.732 dolardır. Kütüphane çalışanları açısından bakıldığında Avustralya ve Yeni Zelanda üniversite kütüphanelerindeki en az personel sayısı 53, Amerika ve Kanada üniversitelerindeki en az personel sayısı ise 117’dir.
  • Placeholder
    ArticlePublicationMetadata only
    Analysis of perlite and pumice based building insulation materials
    (Elsevier, 2016-06) Çelik, S.; Family, Roxana; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Family, Roxana
    Insulation panels composed of perlite, pumice, and cement were fabricated. Perlite and pumice were used to achieve high thermal resistance, and low density. Experimentation was conducted for determining R-values of perlite-pumice-cement (PPC) panels at different moisture content values. Dry and moist sample panels were tested with and without soil and moss at the top where the one with the soil and plant coupling represents a green roof. Reverse heat leak method was used in determination of the R-values of the samples. Verification of theory was achieved via experimentation with an acceptable error range. Thermal diffusivity values of the developed samples were measured using flash method.
  • Placeholder
    ArticlePublicationMetadata only
    Coupled heat transfer analysis and experiments to evaluate the radiative cooling potential of concrete and green roofs for buildings
    (Springer Nature, 2020-08) Family, Roxana; Çelik, S.; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Family, Roxana
    Improving building energy efficiency is one of the most important challenges towards the mitigation of climate change concerns. Buildings use significant amount of energy for cooling loads. Development of new night-time and day-time radiative cooling modalities by roofs is essential for reducing the energy consumption during the summer months. If a surface is desired to be kept cool while exposed to the sun, it should have (i) the maximum reflection of solar energy at visible wavelength range, and (ii) the maximum radiative emission from the surface at atmospheric radiation bands (8-13 mu m wavelength range). In this study, reinforced concrete panels and three different types of plant-covered roof layers were investigated for their potential use for passive cooling applications, including moss, cactus and green leaves. Fourier transform infrared spectroscopy (FTIR) measurements were conducted to determine the absorbance of different samples at infrared wavelengths. In addition, reverse heat leak method was used to determine the effective conductivity values (R-values). The power of cooling parameter of each sample was determined first, and after that a coupled radiation and conduction heat transfer analysis was carried out to evaluate their insulation potential. It was demonstrated that moss is a better candidate to be used as a radiative cooling material, and it is a better insulator than the other tested materials.
  • Thumbnail Image
    Conference ObjectPublicationOpen Access
    Multi-lingual depression-level assessment from conversational speech using acoustic and text features
    (International Speech Communication Association, 2018) Özkanca, Yasin Serdar; Demiroğlu, Cenk; Besirli, A.; Çelik, S.; Electrical & Electronics Engineering; DEMİROĞLU, Cenk; Özkanca, Yasin Serdar
    Depression is a common mental health problem around the world with a large burden on economies, well-being, hence productivity, of individuals. Its early diagnosis and treatment are critical to reduce the costs and even save lives. One key aspect to achieve that goal is to use voice technologies and monitor depression remotely and relatively inexpensively using automated agents. Although there has been efforts to automatically assess depression levels from audiovisual features, use of transcriptions along with the acoustic features has emerged as a more recent research venue. Moreover, difficulty in data collection and the limited amounts of data available for research are also challenges that are hampering the success of the algorithms. One of the novel contributions in this paper is to exploit the databases from multiple languages for feature selection. Since a large number of features can be extracted from speech and given the small amounts of training data available, effective data selection is critical for success. Our proposed multi-lingual method was effective at selecting better features and significantly improved the depression assessment accuracy. We also use text-based features for assessment and propose a novel strategy to fuse the text- and speech-based classifiers which further boosted the performance.
  • Placeholder
    ArticlePublicationMetadata only
    Thermal analysis of perlite-reinforced concrete panels at varying moisture contents
    (Begell House Inc., 2020) Çelik, S.; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar
    Research on composite materials to be used in building insulation is presented. Building energy efficiency gained much broader significance following the COP 21 Paris agreement. In light of this outcome, this study focuses on the analysis of a construction material with improved potential building energy performance. A composite material consisting of Portland cement and perlite was developed and tested. R-values of perlite-reinforced panels at different moisture levels were measured by using the reverse heat leak method. Results obtained by this method were verified by testing materials with known properties and compared to theoretical calculations. Verification of theory was achieved within 1.8% error range. 'Thermal diffusivity values of the developed samples were also measured using the flash method. It was observed that addition of perlite to cement increases the thermal insulation capacity while thermal resistance decreases with increasing moisture content in the panels. Thermal diffusivity was found to be increasing up to a critical moisture level beyond which it decreases due to the effect of density of water that dominates the increase in thermal conductivity. These findings are considered to be significant for the construction industries, especially for regions with abundant perlite reserves.