Selcuk University Journal of Engineering, Science and Technology
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TÜRKİYE'DE ENERJİ TALEBİNİ TAHMİN ETMEK İÇİN DOĞRUSAL FORM KULLANARAK GSA (YERÇEKİMİ ARAMA ALGORİTMASI) VE IWO (YABANİ OT OPTİMİZASYON ALGORİTMASI) TEKNİKLERİNİN UYGULANMASI
Get PDFBu çalışma, Türkiye'deki ekonomik göstergelere dayalı enerji talep tahmini ile ilgilidir. Enerji talebini tahmin etmek için Yerçekimi Arama Algoritması (GSA) ve Yabani Ot Algoritması (IWO) tekniklerine dayanan iki farklı model önerilmektedir. GSA yöntemi, Newton’un hareket ve yerçekimi kanunlarından esinlenerek geliştirilmiş sezgisel optimizasyon algoritmasıdır. IWO algoritması ise doğadaki yabani otların istilacı karakterlerinden esinlenen, evrimsel bir optimizasyon algoritmasıdır. GSA ve IWO yöntemlerine dayalı enerji talep modelleri, gayri safi yurtiçi hâsıla (GSYİH), nüfus, ithalat ve ihracat verilerini giriş parametresi şeklinde kullanan bir model olarak önerilmektedir. Önerilen yöntemler doğrusal regresyon modeli kullanılarak geliştirilmiştir. Türkiye’nin gelecekteki enerji talebi ise üç farklı senaryo altında tahmin edilmektedir. Önerilen tahmin modellerinden elde edilen deneysel sonuçlar karşılaştırmalı olarak verilmiştir. 1979 ve 2005 yılları arasındaki veriler kullanılarak gerçekleştirilen tahmin modelinde IWO literatürdeki diğer yöntemlerle de kıyaslanmış ve IWO yöntemi en yüksek performansı verdiği görülmüştür. 1979 ve 2011 yılları arasındaki tüm veri seti kullanılarak gerçekleştirilen tahmin modelinde ise GSA, IWO yöntemiyle karşılaştırılmış ve GSA daha iyi bir performans elde etmiştir
DİJİTAL FOTOGRAMETRİ YÖNTEMİ İLE ZEMİN KAYMA YÜZEYLERİNİN BELİRLENMESİ
Get PDFTemeller, üst yapı yüklerini zemine aktaran yapı elemanlarıdır. Yapısal bütünlüklerini korurlarken üzerinde bulundukları zeminleri de aşırı gerilmelere zorlamamalıdırlar. Aşırı gerilmeler zeminde kayma yenilmesine veya aşırı oturmalara neden olabilir. Bu nedenle temel tasarımları hem geoteknik ve hem de yapısal gereksinimleri ekonomik olarak karşılamak zorundadır. Geoteknik gereksinimler, temellerin üzerine oturtulacağı zemin veya kayanın izin verilebilir taşıma gücüne ve oturma kriterlerine yöneliktir.Taşıma gücünü arttırmak ve oturmaları izin verilen değerlerde tutmak için zemin içerisine yerleştirilen çeşitli donatılar (geotekstil, geogrid vb.) kullanılmaya başlanmış olup, günümüzde kullanımları hızla artış göstermektedir. Geogridler, yüksek çekme dayanımı, elastisite modülü ve sıyrılma direncine sahip, üzerinde düzgün olarak dağılmış elips, dikdörtgen ya da kare boşluklar bulunan ve özellikle zemin güçlendirmesinde kullanılan bir geosentetik türüdür.Model temellerle yükleme deneylerinde sınır taşıma gücüne ulaşıldığı anda kırılma yüzeyleri çıplak gözle görülememekte, kırılma yüzeylerini görmek için deneye bir süre daha devam ederek temelin oturmasının artması gerekmektedir. Bu durumda çıplak gözle belirlenen kırılma yüzeyleri gerçekte kırılma anına karşılık gelen yüzeyler olmadığından ölçülen kırılma geometrisi de gerçek durumu yansıtmamaktadır.Bu çalışmada kırılma yüzeylerinin fotogrametri tekniği ile yüklemenin başlangıcından sonuna kadar sürekli olarak izlenebilmesidir. Bu amaçla, geogrid donatılı ve donatısız kum üzerine oturan sürekli temellerde taşıma gücünü etkileyen değişik faktörlere göre belirlenen deneyler yapılmış ve fotogrametrik olarak izlenmiştir. Deneylerde çekilen fotoğraflar dijital fotogrametri tekniğiyle değerlendirilerek kayma yüzeyleri sayısallaştırılarak koordinatları belirlenmiştir. Bu teknik ile donatılı ve donatısız zeminlerde oluşan kayma yüzeyleri daha doğru bir şekilde belirlenmiştir
MEGA ŞEHİR İSTANBUL'UN FIRTINALARININ ARAŞTIRILMASI
Get PDFBu çalışmada İstanbul'da bulunan 10 meteoroloji istasyonunun 1970 ile 2016 yılları arasında meydana gelen fırtınaları araştırılmıştır. 47 yıllık periyodda 301 gün, fırtınalı gün olarak tespit edilmiştir. Mevsimsel olarak değerlendirdiğimizde fırtınaların % 60.1 Kış, % 12.6 İlkbahar, % 4.0 Yaz ve % 23.3 Sonbahar mevsimlerinde meydana gelmiştir. 47 yıllık periyodda yıllık ortalama fırtınalı gün sayısı 6.4 ve hamle değeri en yüksek 32.9 m/s rüzgar şiddetiyle Şile Meteoroloji İstasyonu'nda ölçülmüştür. Fırtına sayısı ve şiddetinde azalan yönde lineer trend bulunmaktadır
SYNTHESIS OF Ag-DOPED ZnO NANO FIBERS USING ELECTROSPINNING METHOD AND THEIR PHOTOCATALYTIC ACTIVITIES
Get PDFSilver (Ag) doped zinc oxide (ZnO) nanofibers with 1 at% and 3 at% Ag content were prepared using the electrospinning technique and their structural, morphological and photocatalytic properties were investigated. Pure ZnO nanofibers were also prepared with the same procedure for structure and property related comparison purposes. The photocatalytic activity of the Ag doped ZnO nanofibers were determined as a function of Ag content by exploring the degradation behavior of methylene blue under UV light irradiation. It was found that photocatalytic ability of fibers was improved with Ag addition and higher Ag incorporation resulted better methylene blue degradation rate. For pure ZnO fibers, the remaining dye was 48% of its initial amount after 270 min of UV irradiation time. For the same irridation time, 60% and 67% decomposition ratios of the dye molecules were achieved with the fibers containing 1 at.% Ag and 3 at.% Ag, respectively. The origin of the improvement of photocatalytic activity in Ag doped ZnO nanofibers was attributed to the substitutional incorporation of Ag ions into Zn sites within the ZnO crystal. The substitutional incorporation has been proved with the positional shift of the XRD diffraction lines
FAST K-MEANS COLOR IMAGE CLUSTERING WITH NORMALIZED DISTANCE VALUES
Get PDFImage segmentation is an intermediate image processing stage in which the pixels of the image are grouped into clusters such that the data resulted from this stage is more meaningful for the next stage. Many clustering methods are used widely to segment the images. For this purpose, most clustering methods use the features of the image pixels. While some clustering method consider the local features of images by taking into account the neighborhood system of the pixels, some consider the global features of images. The algorithm of K-means clustering method, that is easy to understand and simple to put into practice, performs by considering the global features of the entire image. In this algorithm, the number of cluster is given by users initially as an input value. For the segmentation, if the distribution of the pixels on a histogram is used, the algorithm runs faster. The values in the histogram must be discrete in a certain range. In this paper, we use the Euclidean distance between the color values of the pixels and the mean color values of the entire image for taking advantage of the every color values of the pixels. To obtain a histogram that consists of discrete values, we normalize the distance value in a specific range and round the values to the nearest integer for discretization. We tested the versions of K-means with the gray level value histogram and the distance value histogram on an urban image dataset getting from ISPRS WG III/4 2D Semantic Labeling dataset. When comparing the two histograms, the distance value histogram that is proposed in this paper is better than the gray level value histogram
INDOOR SURVEYING WITH TERRESTRIAL PHOTOGRAMMETRY: A CASE STUDY FOR SIRCALI MASJID
Get PDFAnatolian lands have many valuable cultural heritages in herited from the past to present because they have been home to many different cultures and civilizations throughout history. Nowadays restoration and documentation studies are carried out in order to keep these works alive and transfer them to next generations. For this purpose, classical or modern techniques are prefered. The terrestrial photogrammetry method, which is one of the modern measurement and evaluation techniques, offers economical, practical, accurate and 3D solutions for architectural surveys. When the 3D modeling studies are examined in the literature, it is generally observed that weight is given to external facade surveying of works. However, many of the works hosted by Anatolia are also actually rich with interior architecture. Numerous Masjid and Mosque examples can be given of these works. Inparticular, the domed interior spaces geometry of mosques and masjids provide information about the architectural and engineering knowledge of the period they were built. In this study, indoor 3D modeling study of Sırçalı Masjid in located in the Karatay district of Konya province was carried out by using the terrestrial photogrammetry method. The Masjid was built in the single-domed masjid type of Seljuk period. The single-domed masjid type is a type of building with square or rectangular base area. However, in order for the dome design to fit in to a square or rectangular sub-structure, a transitional element is needed. The Turkish Triangle was used as transition elementst of facilitate the transition from a square-shaped sub-structure to a circular structure in Sırçalı Masjid. With this study, the dome transition elements, which are difficult to model in terms of classical architectural survey, have been modeled successfully by the terrestrial photogrammetry technique in a short time. It has also been proven that terrestrial photogrammetry can be used effectively in the indoor 3D modelling projects.
A STUDY FROM JUNK MARKET TO THE PRODUCTION OF 5.25% EFFICIENT DYE-SENSITIZED SOLAR CELLS
Get PDFThis paper reveals that having limited facilities is just an excuse not to do any experimental research in most of the universities and institutions all over the world. This may sound impractical for developed countries; however, it is one of the most fundamental problems for underdeveloped and even for some of the developing countries. In this paper, I explain a study of building a laboratory mostly using homemade devices from junks. This paper might be a good and encouraging reference especially for low-income countries, some universities/institutions with very limited budget around the world as well as some students/researchers who want to have their own tools to conduct a research. After a brief explanation to build some of the tools using junks, I will demonstrate the production of dye-sensitized solar cells using homemade equipments with up to 5.25% power conversion efficiency (PCE) under AM1.5 simulated light emission. Structural, electrical and photovoltaic properties of the fabricated devices were also investigated using scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), and current-voltage (IV) characterization tools in this paper
MONITORING THE LONG TERM URBAN EXPANSION OF ZANJAN CITY USING REMOTE SENSING AND GEOGRAPHIC INFORMATION SYSTEMS
Get PDFThe growing phenomenon of urbanization, especially in developing countries, has led to the enlargement of urban areas. Due to the complex structure of cities, changes in the boundaries of a city, whether horizontally or vertically, affects the ecosystem and the quality of life of the corresponding communities. It is also important for the urban planners from the perspective of sustainable development to identify land use/cover changes. The purpose of this paper is to study and evaluate the spatiotemporal expansion of Zanjan city in five time periods. In this research, aerial photographs of 1973, 1982, 1998 as well as satellite images of 2008 and 2016 of the Zanjan city were used. After data preparation in GIS environment, each produced map was classified into two classes of built and not built. Two spatial distribution indexes (PD and CONTAG) as well as land surface and class level measurements were used to determine the characteristics of urban physical development in Zanjan. The results revealed that during the assessed time period, the city has become more sprawled, discontinuous, and in terms of variety of land uses has become more diversified. These results warn that if the urban expansion continues with the existing trend, historical contiguity and compactness of Zanjan city will loss in the near future. This trend may cause several problems
ANALYSES OF ROCK SURFACE COLOUR CHANGES DUE TO WEATHERING
Get PDFDescription parameters of rock masses and minerals include their colours as well. Colours appear in daylight for surfaced rock masses are changing slightly due to weathering layers which have been covering its surface gradually. Healthy human eyes can manage to differentiate visible spectrum to identify the colours of substance including rock masses. Then visible blackish colours of magnetite minerals, reddish colours of Terra- Rosa soils, greenish colours of weathered copper ore, pure white of salt minerals and many others are differentiable by naked eyes. Different colours and homogeneity of colour distribution for natural rocks are also main grading parameters of natural rock surfaces. In addition, colour can also be parameter to identify weathered rock surfaces. Outcrop rock mass surfaces or rock discontinuity surfaces which could be influenced by outside factors, mainly water, and their colours are differentiated. In this study, colour changes were determined in digital manner by obtaining rock surfaces’ Red, Green, Blue digital colour (RGB) values. Digital colour differences have been then analyzed more specifically to evaluate rock weathering and colour changes.
A FUZZY LOGIC APPROACH FOR THE ESTIMATION OF PERFORMANCE HYDROXY DRY CELL WITH DIFFERENT PLATE COMBINATION
Get PDFIn this study, hydroxy (HHO) dry cell with different plate combination performances in terms of current, temperature and flow rate were experimentally investigated and modeled with Rule-Based Mamdani-Type Fuzzy (RBMTF) modeling technique. Input parameters plate number and time; output parameters current, temperature and flow rate were described by RBMTF if-the rules. The dimensions of the plates were 10x10 cm2 and 11x11 cm2. Current and temperature were measured for the different plate combination. This paper presents a fuzzy logic based study for estimating the uncertainty of the HHO drycell parameters. The 80 values between 90th and 270th seconds, which are not obtained from experimental work for 10x10 cm2 and 11x11 cm2 current, temperature and flow rate are predicted by fuzzy logic method. One of the results is; the current value predicted by RBMTF for the 11-2 plate combination and t=90 s is less than the current value from the results of the experimental work for the 11-2 plate combination and t=60 s, but higher than the current value from the results of the experimental work for 11-2 plate combination and t=120s.The comparison between experimental data and RBMTF is done by using three different statistical method. These are, root mean square error (RMSE), mean absolute error (MAE) and the coefficient of multiple determination (R2). For 10x10 cm2 dimension plate, RMSE, MAE and R2 for the current is 0.13, 0.111 and 96.44% respectively. For 11x11 cm2 dimension plate, RMSE, MAE and R2 for the current is 0.07926, 0.06466 and 98.44% respectively. coefficient of multiple determinations (R2). As a result, RBMTF model has shown satisfying relation with experimental results, which suggests an alternative approach to estimation of performance HHO dry cell with different plate combination