TR-Dizin İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/396
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Article Geological-Geochemical Signatures of Opal Occurrences in Keciborlu (Isparta-Turkey)(Pamukkale Univ, 2022) Baspinar Tuncay, Ebru; Koken, Ekin; Kuscu, Mustafa; Cengiz, Oya; Aydemir, Fatih; Raimov, Rahmen; Tuncay, Ebru BaspınarSilica-rich solutions, considered as the final products of acidic volcanism, which started from the Late Miocene to throughout the Plio-Quaternary around Isparta, are effective along the main fault observed around the Keciborlu (Isparta) sulfur deposit. Therefore, opal occurrences are intensively observed along this fault zone. Opal occurrences are in various colors such as gray, beige, yellowish, reddish, blackish. Opals with a massive structure, observed as bands, are sharp -edged, conchoidal diffraction, translucent, matte, oily glossy surface opals are iron oxidized. Some opals contain brecciated rock fragments. The locations of the opal occurrences in the field were determined in this study. Using representative samples, structural and textural properties of opals were determined by thin section, scanning electron microscopy analyses, and mineral paragenesis was analyzed via x-ray diffraction and Fourier transform infrared spectroscopy analyses. Geochemical findings revealed chemical compositions. Based on the thin-section studies, it was observed that the opalized samples lost their primary properties due to the effect of hydrothermal solutions and they became iron oxidized, laminated, and argillized. In addition, they contain opaque minerals such as magnetite and hematite. Different micro textures such as amorphous, granular, desert rose, and lepisphere quartz associations were observed in SEM images. In the XRD and FTIR analyzes, it was determined that most of the opals were Opal CT and some of them were defined as Opal C type. Based on the geochemical analyses considering Ba <120 ppm and Ca >200 ppm, the remarkable changes in loss on ignition values, and the relative relationship between C/T ratio and Ga, such hydrothermal alterations in opals the Keciborlu opals were found to have the magmatic origin.Article Citation - WoS: 1GIS-AHP Approach for a Comprehensive Framework to Determine the Suitable Regions for Geothermal Power Plants in Izmir, Turkiye(Konya Teknik Univ, 2024-02-15) Koca, Kemal; Karipoglu, Fatih; Ozturk, Emel ZerayGeothermal energy is gaining more reputation and importance around the world. Correspondingly, suitable location selection is a critical step and has become necessary for the successful installation and operation of geothermal power plants. This study investigated suitability of & Idot;zmir region, located in the Aegean part of T & uuml;rkiye, in terms of geothermal power plants applications by using the combination of Geographical Information System and Analytic Hierarchy Process. Based on the request of power plants, thirteen important criteria were evaluated under three main categories named as physical (C1), environmental (C2) and technical (C3). Moreover, expert's opinions were taken into consideration to calculate the importance of these criteria. Key results showed that & Idot;zmir was suitable for geothermal power plants. The final suitability map layer pointed out that %8.73 (1.037 km2) of total area were determined as highly suitable regions in terms of installation. In addition, the obtained suitability map layer was compared with actual geothermal power plants. Based on the comparison study, power plants in Seferihisar were moderately suitable for geothermal power plants while the location of Bal & ccedil;ova power plant was highly suitable. Regarding the suitability assessment in the present study, the location of Dikili power plants had the least suitability score.Article Citation - Scopus: 6A Comparative Study to Estimate the Mode I Fracture Toughness of Rocks Using Several Soft Computing Techniques(Murat Yakar, 2023-10-05) Köken, E.; Kadakci Koca, Tümay; Koca, Tümay KadakciFracture toughness is an important phenomenon to reveal the actual strength of fractured rock materials. It is, therefore, crucial to use the fracture toughness models principally for simulating the performance of fractured rock medium. In this study, the mode-I fracture toughness (KIC) was investigated using several soft computing techniques. For this purpose, an extensive literature survey was carried out to obtain a comprehensive database that includes simple and widely used mechanical rock parameters such as uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS). Several soft computing techniques such as artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), gene expression programming (GEP), and multivariate adaptive regression spline (MARS) were attempted to reveal the availability of these methods to estimate the KIC. Among these techniques, it was determined that ANN presents the best prediction capability. The correlation of determination value (R2) for the proposed ANN model is 0.90, showing its relative success. In this manner, the present study can be declared a case study, indicating the applicability of several soft computing techniques for the evaluation of KIC. However, the number of samples for different rock types should be increased to improve the established predictive models in future studies. © 2023 Elsevier B.V., All rights reserved.Article Modeling the Throughput of Horizontal Shaft Impact Crushers Using Regression Analyses, Artificial Neural Networks and Multivariate Adaptive Regression Spline(2022-10-27) Koken, EkinBu çalışmada, yatay milli darbeli kırıcıların (HSI) kırma kapasitesinin (Q), regresyon analizleri, yapay sinir ağları (ANN) ve çok değişkenli uyarlamalı regresyon analizi (MARS) kullanılarak araştırılmıştır. Bu amaçla, Türkiye'deki çeşitli taş ocaklarında ikincil kırma işlemlerinde kullanılan 32 farklı HSI tipi kırıcı ele alınmıştır. Çeşitli sayısal veriler (rotor genişliği (Rw), rotor çapı (Rd), rotor hızı (Vr), karakterize edilen besleme boyutu (d80), çalışma enerjisi (Oe) ve kırmataşın Los Angeles aşınma değeri (LAAV)) her bir kırma–eleme tesisinden elde edilmiştir. Öncelikle, toplanan veriler kullanılarak doğrusal ve doğrusal olmayan regresyon analizleri gerçekleştirilmiştir. Daha sonra ise, bu kırıcıların Q değerini tahmin etmek için farklı ANN ve MARS analizleri yapılmıştır. Sonuç olarak, kırıcıların Q değerini tahmin etmek için güçlü tahmin modelleri geliştirilmiştir. Önerilen modellerin (M6–M10) belirleme katsayısı (R2) 0.91 ile 0.98 arasında değişmekte olup, söz konusu yüksek R2 değerleri geliştirilen modellerin göreceli başarısını göstermektedir. Bu nedenle, önerilen modeller, araştırılan HSI tipi kırıcıların Q değerini tahmin etmek için güvenilir bir şekilde kullanılabilir. Bununla birlikte, HSI tipi kırıcıların Q değerini etkileyen diğer faktörleri araştırmak için örnek çalışmalarının sayısı arttırılmalıdır.