Civil Engineering / İnşaat Mühendisliği

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14th of the International Conference on Hydroscience and Engineering, Iche 2022: Proceeding Book
(Izmir Institute of Technology, 2022) Elçi, Şebnem; Bombar, Gökçen
14th of the International Conference on Hydroscience & Engineering, ICHE 2022 will be held in Izmir, Turkey on 26-27 May, 2022. The International Conference on Hydroscience & Engineering began in Washington DC in 1993, and followed by Beijing hosted ICHE in 1995, Cottbus (1998), Seoul (2000), Warsaw (2002), Brisbane (2004), Philadelphia (2006), Nagoya (2008), Chennai (2010), Orlando (2012), Hamburg (2014) Tainan (2016) and Chongqing (2018). These conferences provided a common ground researchers and engineers to report and discuss the latest scientific advancements and practitioner’s solutions in hydroscience and engineering. ICHE 2022 conference aims to bring together researchers and practicing engineers to share the latest scientific and technological advancements in hydroscience and engineering, and will provide networking opportunities for future activities. Participants will be able to hear experts in the field discuss the latest achievements in issues relevant to Hydro-Engineering for Sustainable Development.
3D modelling of surface spreading and underground dam groundwater recharge: Egri creek subbasin, Turkey
(Springer, 2023) Şahin, Yavuz; Tayfur, Gökmen
Citation - WoS: 11
Citation - Scopus: 11
Adapting Cities To Pluvial Flooding: the Case of Izmir (türkiye)
(MDPI, 2022-12) Salata, Stefano; Couch, Virginia Thompson; Velibeyoğlu, Koray; Baba, Alper; Saygın, Nicel; Uzelli, Taygun
In the coming decades, climate change will be one of the most significant challenges for urban areas. The quantity, duration and intensity of events, such as flash rains and heat waves, will increase the vulnerability of urban regions while exposing citizens to potentially dangerous conditions. According to the current literature, mainstreaming resilience in urban planning means designing rules that strengthen urban systems’ adaptive and self-regulating functions by reducing their vulnerability. In this work, we aimed to build knowledge for the application of the sponge district concept to Izmir (Türkiye), one of Europe’s most vulnerable areas to pluvial flooding. To do this, we first analyzed the runoff in each urban sub-watershed, then employed a composite index to determine potential areas of intervention for nature-based solutions. Results show that 10% of Izmir’s urban areas are extremely vulnerable to cloudbursts, which means that 40% of the urban population is exposed to this phenomenon. Moreover, the runoff calculation in the sub-watershed demonstrated that the potential flood volume is underestimated, especially in the upslope areas. The results can be used as a template to suggest a stepwise approach to mainstream the resilience of densely-inhabited coastal urban catchments.
Akifere Yağıştan Süzülme Miktarının Sondaj Verileri Kullanılarak Tahmin Edilmesi: Alaşehir (manisa) Havzası
(TMMOB Jeoloji Mühendisleri Odası, 2018) Tonkul, Serhat; Baba, Alper; Şimşek, Celalettin; Tayfur, Gökmen; Durukan, Seda; Kumanlıoğlu, Ahmet; Demirkesen, Ali Can
Son yıllarda iklim değişikliğine bağlı su kullanımının artması ve buna ek olarak aşırı nüfus artışı, yeraltısuyu kullanımını arttırmakta ve su kaynaklarını tehdit etmektedir. Su kaynaklarının sürdürülebilirliğinin sağlanması için barajlar ve yapay göller inşa edilmekte, ancak bu yapıların geniş yüzey alanlarında çok fazla buharlaşma görülmektedir. Dolayısı ile yeraltı suyunun, buharlaşma kayıplarının yaşanmadığı direkt yağış ile beslenen yapay beslenmesi önem kazanmaktadır. Yapay beslenme, havzalardaki suyu fazla buharlaşmadan korur ve su kaynaklarının potansiyelini artırıp, sürdürülebilirliğini sağlar. Bu çalışma kapsamında nümerik metotlar kullanılarak, Alaşehir (Manisa) havzasında alüvyon akiferin beslenmesinin belirlenmesi amaçlanmıştır. Türkiye’nin batısında yer alan ve ülkenin %2’sini oluşturan Gediz Havzası, önemli bir yeraltı suyu potansiyelinin olduğu ve kullanıldığı alan konumundadır.
Akıllı otopark sistemlerinde kullanılan araç tanıma teknolojileri üzerine bir inceleme
(Bandırma Onyedi Eylül Üniversitesi, 2022) Doğaroğlu, Bora; Çalışkanelli, S. Pelin
Günümüz şehir planlama ve yönetimi için trafik talebindeki artışın paralelinde otopark talebindeki artış acil çözüm bekleyen sorunlar arasında yer almaktadır. Özellikle otopark talebinin yüksek olduğu şehir merkezlerinde yeterli alan bulunmaması otopark altyapı tesislerinin inşasına olanak tanımamaktadır. Soruna yaygın çözüm olarak kullanılan yöntem mevcut kapasitenin etkin kullanımı ve talep yönetimidir. Akıllı ulaşım sistemleri özellikle Akıllı Otopark Sistemleri (AOS) özelinde düşünüldüğünde kapasitenin uygun kullanımı ve talep yönetimi için en güncel yöntem olarak tercih edilmektedir. AOS’un etkin uygulanabilmesi de etkin araç tanıma ve detektör teknolojilerine bağlıdır. Bu çalışmada AOS’un verimliliği için etken olan araç tanıma detektör sistemleri kategorize edilerek tanıtılmış ayrıca yaygın kullanılan detektör teknolojilerinin avantajları ve dezavantajları dikkate alınarak kıyaslamaları yapılmıştır. Sunulan sınıflandırmalar ile AOS tasarımı yapılırken kullanılacak etkin teknoloji seçimi konusunda yardımcı olmak amaçlanmıştır.
Alaşehir Alt Havzasının (gediz Havzası, Batı Anadolu) Nem Değişimi Yöntemine Göre Yeraltısuyu Besleniminin Değerlendirilmesi
(2021) Durukan, Seda; Şimşek, Celalettin; Tonkul, Serhat; Baba, Alper; Tayfur, Gökmen
Gediz havzası Ege Bölgesinin en önemli havzalarından biridir. Çalışma alanı Gediz havzası içerisinde bulunan Alaşehir alt havzasıdır. Bu çalışma kapsamında Alaşehir alüvyon akifere çok sayıda araştırma kuyusu açılmış olup, araştırma kuyularında zemin karakterizasyonu belirlenmiş ve bazı kuyulara da zemin nem sensörleri konumlandırılarak yeraltısuyu beslenimi hesaplanmıştır. Doygun olmayan bölgedeki zeminlerde nem değişim yöntemi ile yağıştan sonra zemin nem değişimleri belirlenerek yağıştan beslenme miktarı tespit edilebilmektedir. Bu kapsamda alüvyon akifere 5 farklı noktada özel açılan kuyularda 5, 10 ve 15 m derinliklerde nem sensörleri vasıtası ile zemin nemi, sıcaklığı ve tuzluluğu ölçülmüştür. Çalışma alanında seçilen kuyularda zeminin suya doygun olmayan bölgesinde gerçekleştirilen hacimsel su içeriklerine göre mevsimsel değişiklikleri ortaya konulmuş ve yağıştan kaynaklanan beslenme miktarı belirlenmiştir. Elde edilen ölçümler sonucunda, çalışma alanındaki alüvyon akiferdeki yeraltısuyu beslenimi en az 40,81 ile en çok 77,12 mm olacak şekilde, ortalama olarak da 56,83 mm hesaplanmıştır. Ayrıca, ilk kez derin kuyular vasıtası ile yeraltısuyu besleniminde kullanılan zemin nem değişim yönteminin limitasyonları da bu çalışma kapsamında tartışılmıştır.
Alaşehir havzası SMA (Soil Moisture Accounting) hidrolojik modeli
(TMMOB Jeoloji Mühendisleri Odası, 2018) Akdeğirmen, Özgün; Baba, Alper; Şimşek, Celalettin; Tayfur, Gökmen; Kumanlıoğlu, Ahmet
Havza su yönetiminde dinamik hidrolojik koşullarına göre, gerçeğe yakın tahminlerde bulunmak ve bunu mümkün olan en az kaynak kullanımı ile gerçekleştirmek temel hedeflerden biridir. Bu noktada 115Y065 numaralı TÜBİTAK destekli Alaşehir Alt Havzası yeraltısuyu beslenim miktarlarının tespitini hedef alan proje çerçevesinde çalışma alanı için SMA algoritması uygulama çalışmaları yapılmıştır. Çalışmada ArcGIS ve HecHMS programlarından faydalanılmıştır. Havza alanı bölgedeki yeryüzü şekillerine göre değişen alt havzalara bölünmüş olup her bir alt havzanın kendi içerisinde havza parametreleri bakımından homojen bir yapıya sahip olduğu kabulü yapılmıştır. Çalışma alanının yüzey şekilleri dijital yükseklik modelinden ArcGIS programında elde edilip HecHMS havza simülasyon programına aktarılıp alt havza parametreleri (yüzeysel depolama, geçirimsiz alanlar, buharlaşma-terleme vb.) tanımlamıştır. Gelinen noktada girdi olarak verilen yağış değerinin sonucunda bölge içerisinde hali hazırda yer alan akım gözlem istasyonlarının tespit ettiği debilere dayanarak model kalibrasyonu yapılıp sonuçların tutarlılıkları araştırılmıştır.
Citation - WoS: 4
Citation - Scopus: 6
An Alternative Implementation of the Incremental Energy/Dissipation Based Arc-Length Control Method
(Elsevier Ltd., 2019) Özdemir, İzzet
A robust solution algorithm is essential to trace the arduous equilibrium paths typically confronted with in cohesive fracture and continuum damage mechanics of quasi-brittle materials. Although robust arc-length type solvers exist suitable for such problems, the use of these methods is hindered by their non-standard implementation requirements. Departing from this fact, in this paper, the recently proposed arc-length solver presented in reference May et al. (2016) is reconsidered within the limitations/capabilities of the commercial software packages and recast in a form which is suitable for implementation through user element formalism. The constraint equation is re-expressed and appended to the system of equations through the internal force column and tangent stiffness matrix of a user element. The effectiveness of the proposed alternative implementation is illustrated by means of two cohesive fracture problems.
Citation - WoS: 202
Citation - Scopus: 241
Altimetry for the Future: Building on 25 Years of Progress
(Elsevier, 2021) Abdalla, Saleh; Kolahchi, Abdolnabi Abdeh; Ablain, Michael; Adusumilli, Susheel; Bhowmick, Suchandra Aich; International Altimetry Team; Öztunalı Özbahçeci, Bergüzar
In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the Green Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments' development and satellite missions' evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion. (c) 2021 COSPAR. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/
Alüvyon Akifer için Özgül Debi Değeri ile Hidrolik İletkenliğin Tahmin Edilmesi: Alaşehir (manisa) Ovası Örnek Çalışması
(TMMOB Jeoloji Mühendisleri Odası, 2018) Şimşek, Celalettin; Baba, Alper; Aksoy, Niyazi; Demirkıran, Zülfü
Akiferlerin hidrolik iletkenliği, transmissibilitesi ve depolama katsayısı gibi hidrolik parametrelerinin pompaj kuyuları ile belirlenmesi oldukça zor ve pahalı bir işlemdir. Hidrolik iletkenliğin belirlenmesinde, debi, statik seviye, dinamik seviye ve etki yarıçapına ihtiyaç duyulmaktadır. Gözlem kuyuları olmadığı takdirde etki yarıçapı global rakamlarla ifade edilmektedir. Buna karşılık, statik su seviyesi, dinamik su seviye ve kuyu debisi kolaylıkla kuyu başında ölçülebilmektedir. Bu veriler ile kuyunun özgül debisi rahatlıkla hesaplanabilmektedir. Ülkemizde, binlerce su kuyusu alüvyon akiferde açılmaktadır. Kuyuların hidrolik parametreleri ise pompaj testlerinin uygulanamaması nedeni ile bilinmemektedir. Bu çalışma kapsamında ise hidrolik iletkenliğin bölgede aynı akiferden elde edilen özgül debi değerleri ile tahmin edilebilmesine gidilmiştir. Bu çalışma Alaşehir Ovası’nın en önemli yeraltı suyu akiferi olan alüvyon akiferde uygulanmıştır. Büyük miktarda çekilen yeraltısuyu çalışma alanında içme ve sulama amaçlı kullanılmaktadır. İnceleme alanında 120-150 m derinliğinde açılmış olan su kuyularından 5-30 L/s debi ile yeraltı suyu çekilebilmektedir. Açılan bu kuyularda çok az kullanılabilecek hidrolik parametre bulunmaktadır. Bu nedenle, kuyuların hidrolik parametrelerinin belirlenmesinde bilinen parametrelerden yola çıkarak bilinmeyeni tahmin eden yaklaşımlara ihtiyaç duyulmaktadır. Bu verilerden yola çıkarak, çalışma alanında düzgün verisi olan ve alüvyonda açılmış kuyu özgül debi değerleri ile kuyunun hidrolik iletkenliğinin belirlenmesine çalışılmıştır.
Citation - WoS: 1
Citation - Scopus: 2
Ampirik Yöntemlerle Gediz Nehri için Askıda Katı Madde Yükü Tahmini
(Turkish Chamber of Civil Engineers, 2011-04) Ülke, Aslı; Özkul, Sevinç; Tayfur, Gökmen
It is essential to predict suspended sediment load for understanding river morphology, design of dams, water supply problems, management of reservoirs and determination of pollution levels in rivers. The suspended sediment load can be determined by means of several methods such as direct measurements at the sediment gauging stations, sediment rating curve, son modeling methods, and empirical methods which are based on experimental works. The objective of this study is first to determine the best empirical method for Gediz river and then to improve the determined method by genetic algorithm (GA). It is seen that the GA improved Brooks method can be used for Gediz River Basin. In addition, this method was compared with other soft computing (ANN, ANFIS) methods and its performance is found to be as good as them.
Citation - WoS: 40
Citation - Scopus: 50
Analysis and Assessment of Hydrochemical Characteristics of Maragheh-Bonab Plain Aquifer, Northwest of Iran
(Springer Verlag, 2017-02) Fijani, Elham; Moghaddam, Asghar A.; Tsai, Frank T.-C.; Tayfur, Gökmen
The present study aims at assessing the hydrochemistry of the groundwater system of the Maragheh-Bonab Plain located in the East Azarbaijan Province, northwest of Iran. The groundwater is used mainly for drinking, agriculture and industry. The study also discusses the issue of the industrial untreated wastewater discharge to the Plain aquifer that is a high Ca-Cl water type with TDS value of about 150 g/L. The hydrogeochemical study is conducted by collecting and analyzing the groundwater samples from July and September of 2013. The studied system contains three major groundwater types, namely Ca–Mg–HCO3, Na–Cl, and non-dominant water, based on the analysis of the major ions. The main processes contributing to chemical compositions in the groundwater are the dissolution along the flow path, dedolomitisation, ion exchange reactions, and the mixing with wastewater. According to the computed water quality index (WQI) ranging from 25.45 to 194.35, the groundwater in the plain can be categorized into “excellent water”, “good water”, and “poor water”. There is a resemblance between the spatial distribution of the WQI and hydrochemical water types in the Piper diagram. The “excellent” quality water broadly coincides with the Ca-Mg-HCO3 water type. The “poor” water matches with the Na–Cl water type, and the “good” quality water coincides with blended water. The results indicate that this aquifer suffers from intense human activities which are forcing the aquifer into a critical condition.
Citation - WoS: 103
Citation - Scopus: 126
Ann and Fuzzy Logic Models for Simulating Event-Based Rainfall-Runoff
(American Society of Civil Engineers (ASCE), 2006-12) Tayfur, Gökmen; Singh, Vijay P.
This study presents the development of artificial neural network (ANN) and fuzzy logic (FL) models for predicting event-based rainfall runoff and tests these models against the kinematic wave approximation (KWA). A three-layer feed-forward ANN was developed using the sigmoid function and the backpropagation algorithm. The FL model was developed employing the triangular fuzzy membership functions for the input and output variables. The fuzzy rules were inferred from the measured data. The measured event based rainfall-runoff peak discharge data from laboratory flume and experimental plots were satisfactorily predicted by the ANN, FL, and KWA models. Similarly, all the three models satisfactorily simulated event-based rainfall-runoff hydrographs from experimental plots with comparable error measures. ANN and FL models also satisfactorily simulated a measured hydrograph from a small watershed 8.44 km2 in area. The results provide insights into the adequacy of ANN and FL methods as well as their competitiveness against the KWA for simulating event-based rainfall-runoff processes.
Anomalous 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, Alper
In 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.
Citation - WoS: 36
Citation - Scopus: 43
Applicability of Sediment Transport Capacity Models for Nonsteady State Erosion From Steep Slopes
(American Society of Civil Engineers (ASCE), 2002-05) Tayfur, Gökmen
The physics-based sediment transport equations are derived from the assumption that the sediment transport rate can be determined by a dominant variable such as flow discharge, flow velocity, slope, shear stress, stream power, and unit stream power. In modeling of sheet erosion/sediment transport, many models that determine the transport capacity by one of these dominant variables have been developed. The developed models mostly simulate steady-state sheet erosion. Few models that are based on the shear-stress approach attempt to simulate nonsteady state sheet erosion. This study qualitatively investigates the applicability of the transport capacity models that are based on one of the commonly employed dominant variables-unit stream power, stream power, and shear stress-to simulate nonsteady state sediment loads from steep slopes under different rainfall intensities. The test of the calibrated models with observed data sets shows that the unit stream power model gives better simulation of sediment loads from mild slopes. The stream power and the shear stress models, on the other hand, simulate sediment loads from steep slopes more satisfactorily. The exponent (ki) in the sediment transport capacity formula is found to be 1.2, 1.9, and 1.6 for the stream power model, the shear stress model, and the unit stream power model, respectively.
Citation - Scopus: 2
Application 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, Engin
This 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.
Citation - Scopus: 19
Application of Geothermal Energy and Its Environmental Problems in Turkey
(Inderscience Enterprises Ltd., 2015-09) Baba, Alper
Human beings have been benefiting from geothermal energy for different uses since the dawn of the civilisation in many parts of the world. One of the earliest uses of geothermal energy was for heating and it was used extensively by Romans in Turkey. The Aegean region is favoured by a large number of thermal springs known since ancient times. However, it was first in the 20th century that geothermal energy was used on a large scale for direct use and electricity generation. The country's installed heat capacity is 2,705 MWt for direct use and 322.39 MWe for power production. In parallel to developing geothermal energy applications in Turkey, many sites are now experiencing problems such as water contamination associated with geothermal fluid. Especially, the high temperature solution of elements and compounds, causes operational limitations in geothermal power plants. These limitations are due to the severe scaling and corrosion of geothermal fluid. Copyright © 2015 Inderscience Enterprises Ltd.
Citation - WoS: 29
Citation - Scopus: 33
Areally-Averaged Overland Flow Equations at Hillslope Scale
(Taylor and Francis Ltd., 1998-06) Tayfur, Gökmen; Kavvas, M. Levent
Microscale-averaged inter-rill area sheet flow and rill flow equations (Tayfur and Kavvas, 1994) are averaged along the inter-rill area length and rill length to obtain local areally-averaged inter-rill area sheet flow and rill flow equations (local-scale areal averaging). In this averaging, the local areally-averaged flow depths are related to the microscale-averaged flow depths at the outlet sections (downstream ends) of a rill and an inter-rill area by the assumption that the flow in these sections has the profile of a sine function. The resulting local areally-averaged flow equations become time dependent only. To minimize computational efforts and economize on the number of model parameters, local areally-averaged flow equations are then averaged over a whole hillslope section (hillslope-scale areal averaging). The expectations of the terms containing more than one variable are obtained by the method of regular perturbation. Comparison of model results with observed data is satisfactory. The comparison of the model results with those of previously developed models which use point-scale and large-scale (transectionally) averaged technology indicates the superiority of this model over them. Microscale-averaged inter-rill area sheet flow and rill flow equations (Tayfur & Kavvas, 1994) are averaged along the inter-rill area length and rill length to obtain local areally-averaged inter-rill area sheet flow and rill flow equations (local-scale areal averaging). In this averaging, the local areally-averaged flow depths are related to the microscale-averaged flow depths at the outlet sections (downstream ends) of a rill and an inter-rill area by the assumption that the flow in these sections has the profile of a sine function. The resulting local areally-averaged flow equations become time dependent only. To minimize computational efforts and economize on the number of model parameters, local areally-averaged flow equations are then averaged over a whole hillslope section (hillslope-scale areal averaging). The expectations of the terms containing more than one variable are obtained by the method of regular perturbation. Comparison of model results with observed data is satisfactory. The comparison of the model results with those of previously developed models which use point-scale and large-scale (transectionally) averaged technology indicates the superiority of this model over them
Citation - WoS: 2
Citation - Scopus: 2
Arsenic in Groundwater in Western Anatolia, Turkey: a Review
(University of Silesia Press, 2010) Gündüz, Orhan; Baba, Alper; Elpit, Handan
Occurrence of arsenic (As) in groundwater has been a major problem worldwide for the last hundred years. Considering its toxic effects on human health, the presence of elevated levels of arsenic in groundwater resources used in drinking water supply has been an active research field throughout the world (Van Halem et al., 2009). In this regard, case studies from Bangla-desh, India, Nepal, El Salvador, Ecuador, Honduras, Mexico, Chile, China, Canada, Argentina, Peru, Taiwan, United States, Bolivia and Turkey have been documented with regards to the detection of natural levels in groundwater, the occurrence and distribution mechanisms, the human health effects and the in-situ and ex-situ treatment techniques (Jean et al., 2010). In many of these locations, arsenic is naturally found in the subsurface strata within volcanic and sedimentary formations as well as in areas of geothermal systems related to tectonic activity. Western Anatolia in Turkey is one such area of complex geology with active tectonics and high geothermal potential. This natural setting serves as a suitable environment for the presence of high levels of arsenic in subsurface waters. Based on these fundamentals, this study presents a general overview of arsenic presence in western Anatolia.
Citation - WoS: 52
Citation - Scopus: 63
Artificial Neural Network (ann) Prediction of Compressive Strength of Vartm Processed Polymer Composites
(Elsevier Ltd., 2005-08) Seyhan, Abdullah Tuğrul; Tayfur, Gökmen; Karakurt, Murat; Tanoğlu, Metin
A three layer feed forward artificial neural network (ANN) model having three input neurons, one output neuron and two hidden neurons was developed to predict the ply-lay up compressive strength of VARTM processed E-glass/ polyester composites. The composites were manufactured using fabric preforms consolidated with 0, 3 and 6 wt.% of thermoplastic binder. The learning of ANN was accomplished by a backpropagation algorithm. A good agreement between the measured and the predicted values was obtained. Testing of the model was done within low average error levels of 3.28%. Furthermore, the predictions of ANN model were compared with those obtained from a multi-linear regression (MLR) model. It was found that ANN model has better predictions than MLR model for the experimental data. Also, the ANN model was subjected to a sensitivity analysis to obtain its response. As a result, the ANN model was found to have an ability to yield a desired level of ply-lay up compressive strength values for the composites processed with the addition of the thermoplastic binder.