TR Dizin İndeksli Yayınlar / TR Dizin Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7149
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Article Citation - Scopus: 1Anomalous Crustal Structure Beneath the Örenli-Eğiller Depression Zone, Inferred From Magnetotelluric Studies, Western Anatolia, Türkiye(TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2024) Chandrasekharam, Dornadula; Raju, K.; Subba Rao, P.B.V.; Baba, AlperIn Türkiye, the prevalence of high radiogenic granites makes them ideal locations for initiating enhanced geothermal system (EGS) projects. One such occurrence of these granites is observed in the Kozak area of the Bergama region. To assess the energy potential of this site, a magnetotelluric (MT) survey was conducted, focusing on determining the depth distribution of the intrusive granite. The survey employed dimensionality analysis, utilizing Bahr skew and phase tensor analyses that denote a 2D subsurface nature up to 100 s and beyond that a 3D nature. In the present study, we interpreted MT data up to 100 s. The data collected, including rotated impedance tensors and tippers, were inverted using a nonlinear conjugate gradient algorithm integrated into the MT interpretation software of the WinG Link 2D inversion data modeling package. Multiple homogeneous half-space initial models were tested during the 2D inversion process. The findings indicate the existence of a midcrustal conductor associated with graphites and iron sulfides in the source region. This conductivity may be attributed to processes such as exsolution of metamorphic fluids, influx of mantle sources, or the entry of magmatic fluids through transcrustal fault zones. The findings indicate that the intrusive granite was emplaced along a NE–SW major fault, penetrating shallow crustal levels. The depth of this granite intrusion is determined to be 15 km, covering an outcrop area of 60 km². This detailed geological information allows a comprehensive assessment of the power-generating capacity of the intrusive granite. The results of this investigation contribute valuable insights for the development and optimization of Enhanced Geothermal System (EGS) projects in the region. © 2024, TUBITAK. All rights reserved.Article Citation - Scopus: 2Application of Endurance Time Method in Seismic Assessment of Rc Frames Designed by Direct Displacement-Based Procedure(Turkish Chamber of Civil Engineers, 2024) Karımzada, Nisar Ahmad; Shırkhanı, Amir; Aktaş, EnginThis paper addresses the Direct Displacement-Based Design (DDBD) approach of multi-story RC frame structures consistent with changes to design criteria between Turkish earthquake codes of TSC-2007 and TBEC-2018. The corresponding response modification factor (R) of structures designed based on the DDBD approach is also estimated in this research. The design base shear forces of both codes are compared considering different R factors and also with that of the DDBD approach. The results showed that the DDBD approach, as per TBEC-2018, provides RC frame structures with higher R values compared to the similar approach in accordance with TSC-2007. The Endurance Time (ET) method is a time history-based procedure for seismic assessment of structures under intensifying dynamic excitations aided to judge their performance at various intensity levels. Since, up to now, the ET method has not been considered to evaluate the performance of the structures designed by the DDBD approach, this paper addresses this issue. The ET performance curves of RC frames show that structures designed by the DDBD approach in accordance with TBEC-2018 exhibit higher Interstory Drift Ratios (IDRs) values than TSC-2007 at various hazard levels.Article Citation - WoS: 6Citation - Scopus: 7Magnetotelluric Investigations Over Geothermal Provinces of India: an Overview(TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2023) Prabhala, Bhaskhara Venkata Subba Rao; Pachigolla, Venkata Vijaya Kumar; Chandrasekharam, Dornadula; Deshmukh, Vasu; Singh, Ajay KishoreMagnetotelluric (MT) and audio-magnetotelluric (AMT) studies are sensitive to the geothermal fluids filling the faults and/ or fracture zones of the geothermal system. In India, MT/AMT studies have been carried out in NW Himalayas, central, eastern, and western India. In other areas, detailed MT/AMT studies need to be expedited. This review paper presents the art of geothermal exploration in India by using MT/AMT techniques and identifies potential zones that can be exploited for power generation and direct application. Reservoir characteristics, carbon emissions reduction methods, and levelised cost factor are also discussed. © TÜBİTAK.Article Citation - WoS: 10Citation - Scopus: 11Meteorological Drought Analysis for Helmand River Basin, Afghanistan(TMMOB İnşaat Mühendisleri Odası, 2022) Alami, Mohammad Musa; Tayfur, GökmenThis study evaluates drought at Lashkargah, Farah, Adraskan, and Gardandiwal stations in Helmand River Basin (HRB) in Afghanistan to determine appropriate drought indices for the basin. Thirty seven years of monthly recorded precipitation data from 1979 to 2015 are employed with different drought index (DI) methods which include the Standardized Precipitation Index (Normal-SPI, Log-SPI, and Gamma-SPI), the Percent of Normal (PN), and the Deciles. All the methods are applied to the annual long term precipitation data. The log-SPI and the gamma-SPI predict extreme drought conditions, whereas, the normal-SPI determines wet and less dry conditions. The results emphasize that the PN and the Deciles methods predict more drought years in comparison to the SPI methods. The Deciles method shows longer period of extreme and severe drought than other methods. The five methods indicate various drought intensities in 1985, 1987, 1994, 1997, 1999, 2000, 2001, 2002, 2003, and 2004 at all the stations. The extreme drought condition in 2001 at all the stations confirms to the recorded drought reports for the same region. It is noted that since the log-SPI and the gamma-SPI capture the historical extreme and severe drought periods successfully, these are recommended as the drought monitoring indices for Helmand River Basin.Article Citation - WoS: 1Citation - Scopus: 1Fragility Analysis of Wide-Beam Infill-Joist Block Rc Frames(Gazi Üniversitesi, 2022) Dönmez, Cemalettin; Karaarslan, Enes; Erberik, Murat AltuğPurpose: The purpose of the presented study is to develop fragility curves for the wide-beam infill-joist block reinforced concrete structures. Theory and Methods: Nonlinear time history analyses are performed for the set of selected ground motions. The performance levels are identified through pushover analysis and fragility curves are produced for ground motion parameters. Results: Fragility curves obtained for the wide-beam RC frames presents a different characteristic than the curves obtained for the conventional frames. Conclusion: Results show that wide-beam RC frame buildings are seismically more vulnerable than the conventional deep beam RC frame buildings based on structural models with similar properties. The possible reason seems to be low lateral stiffness of wide-beam frames that causes large lateral drift demands and therefore severe damage at the wide-beam column connections.Article Citation - WoS: 13Citation - Scopus: 15High Heat Generating Granites of Kestanbol: Future Enhanced Geothermal System (egs) Province in Western Anatolia(TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2021) Chandrasekharam, Dornadula; Baba, AlperAlthough the western Anatolian region is a foci for hydrothermal systems, this region has several high heat-generating granitic intrusive bodies that qualify to be candidates for enhanced geothermal systems (EGS). Considering the future energy requirement, carbon dioxide emissions reduction strategies, food, and water security issues, these granites appear to be the future clean energy source for the country. One such granite intrusive is located in the Kestanbol area in the western Anatolian region. The radioactive heat generation of this 28 Ma old granite varies from 5.25 to 10.38 µW/m3 with a heat flow of 92.47 to 128.61 mW/m2 . These values concur with the measured geothermal gradients and heat flow values measured from exploratory bore wells. High radon content in the thermal waters in these areas indicates interaction between the circulating fluids and the Kestanbol granite. This is for the first time evaluation of the EGS potential of granite intrusive in Turkey has been made. The Kestanbol intrusive is placed under a compressive stress regime within the Anatolian-Aegean regional tectonic framework.Article Citation - WoS: 3Citation - Scopus: 5Use of Geothermal Fluid for Agricultural Irrigation: Preliminary Studies in Balçova-Narlıdere Geothermal Field (turkey)(2021) Meriç, M. Kamil; Kukul, Yasemin Senem; Özçakal, Emrah; Barlas, N. Tuba; Çakıcı, Hakan; Jarma, Yakubu Abdullahi; Kabay, Nalan; Baba, AlperBalçova-Narlıdere Geothermal Field (BNGF) hosts the largest geothermal district heating system of Turkey and several geothermal wells used for district heating and thermal tourism activities. This study assesses the use of BNGF geothermal fluid for agricultural activities. The spent geothermal brine was treated using nanofiltration and reverse osmosis membranes on a pilot-scale membrane test system. The qualities of the product were evaluated in terms of agricultural irrigation integrated with the implemented innovative wireless sensor network. It is important to use geothermal fluid, which is consists of valuable minerals, for irrigation. But when using geothermal fluid in irrigation, the chemical composition of the water must be carefully monitored to prevent damage to the plants. Nevertheless, the first result shows that the use of geothermal fluid to irrigate is proving to be a promising and economically viable option in BNGF.Article Sonlu Eleman Modellerinin Maksimum Olasılık Tahmini ile Güncellenmesi(Turkish Chamber of Civil Engineers, 2021) Hızal, ÇağlayanMatematiksel yapı modellerinin titreşim verileri kullanılarak güncellenmesi konusu, son yıllarda giderek artan bir şekilde araştırmacıların ilgisini çekmektedir. Bu hususta literatüre sunulan yöntemler genel olarak deterministik ve olasılıksal olarak sınıflandırılmaktadır. Bu bağlamda hem deterministik hem de olasılıksal model güncelleme yöntemlerinin birçok varyasyonu yer almaktadır. Bu çalışmada ise maksimum olasılık tahminine dayalı alternatif bir yaklaşım sunulmaktadır. Önerilen yöntemde, modal tanılama sırasında öngörülen ölçüm hatalarının yanı sıra model hatası da boyutsuz bir Rayleigh oranı üzerinden dikkate alınmaktadır. Sisteme ait model parametreler, ölçüm ve modelleme hatalarının normal dağılım göstereceği kabulüyle oluşturulan bir olasılık yoğunluk fonksiyonu üzerinden hesaplanmaktadır. Sunulan yöntemin güvenirliği bir sayısal ve bir deneysel uygulama üzerinden değerlendirilmiştir. Elde edilen verilere göre önerilen yöntemin oldukça makul sonuçlar verdiği gözlemlenmektedir.Article Mesnetlerinden Farklı Yer Hareketlerine Maruz Çok Katlı Çerçevelerin Deplasman Yüklemesine Göre Analizi(Turkish Chamber of Civil Engineers, 2019) Hızal, Çağlayan; Turan, GürsoyIn seismic analysis of structures, generally it is assumed that all supports are subjected to identical ground motions. This approach is assumed to be realistic when the foundation of the structure is formed as a rigid plate, but it cannot consider the dynamic effects of the earthquake wave propagation if the supports are able to move independently. In this study, the multi-support excitation analysis of multi-story, multi bay frames is performed by using displacement loading which defines the seismic load depending on the ground displacement. The modal analysis procedure of the structures subjected to multi-support excitations is given in detail and the effect of pseudo-static displacement on the dynamic response of the structure is highlighted. A static correction approach is implemented with a numerical example to reflect the higher mode effects which are a natural result of displacement loading.Article Citation - WoS: 3Citation - Scopus: 5Helenistik Kulelerde Yanal Yüke İlişkin Düzlem İçi ve Düzlem Dışı Duvar Davranışının Duvar Profilleri ve Açıklık Düzenlerine Bağlı Olarak İncelenmesi(Gazi Üniversitesi, 2020) Gençer, Funda; Turan, Mine; Aktaş, EnginDry masonry wall profiles constructed without using bonding material between blocks are encountered in different building types dated to Greek, Hellenistic and Roman periods. Depending on development of earthquake experiences, dry masonry wall profiles vary in terms of wall thickness, number of layers, relationship of layers and size, form, organization and relationship of blocks. In this study, the construction details increasing the structural strength in watch towers constructed in Hellenistic Period are aimed to be determined. This study is limited with investigation of effect of wall profiles and opening organizations on in-plane and out-of-plane wall behaviors under lateral loading. Primarily, wall profiles and opening types of dry masonry towers in ancient Caria, Pamphylia and Cilicia regions, that have not lost authenticity and integrity or had information about their authentic form, were documented. By using gathered data, hypothetic towers with different wall profiles and opening types are designed. To determine in-plane and out-of-plane wall behavior of hypothetic towers, simulation of quasi-static tilt analysis based on equilibrium were carried out, and form changes at walls and collapse angles of towers were identified. Wall profile and opening properties effecting on structural strength under lateral loading were determinedd.
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