Evidence of extensive carbonate mounds and sublacustrine channels in shallow waters of Lake Van,eastern Turkey,based on high-resolution chirp subbottom profiler and multibeam echosounder data     

Deniz Cukur  Sebastian Krastel  M. Namık Çağatay  Emre Damcı  Aysegül Feray Meydan  Seong-Pil Kim 《Geo-Marine Letters》2015,35(5):329-340

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The Risk Atlas of Mexico City,Mexico: a tool for decision-making and disaster prevention     

Novelo-Casanova  David A.  Suárez  Gerardo  Cabral-Cano  Enrique  Fernández-Torres  Enrique A.  Fuentes-Mariles  Oscar A.  Havazli  Emre  Jaimes  Miguel Á.  López-Espinoza  Erika D.  Martin-Del Pozzo  Ana Lillian  Morales-Barrera  Wendy V.  Morales-Rodríguez  Hipólito L.  Nieto-Torres  Amiel  Rodríguez-Elizarrarás  Sergio R.  Solano-Rojas  Darío  Velasco-Herrera  Victor M. 《Natural Hazards》2022,111(1):411-437

Natural Hazards - We present a Risk Atlas of Mexico City based on a Geographical Information System (RA-GIS). We identified the prevalent social risk to the more relevant hazards in Mexico City...  相似文献   

Entropy change and phase transitions in an expanding Universe     

N. Iqbal  T. Masood  N. Demir 《Astronomische Nachrichten》2015,336(10):1025-1032

The work compiles a correlated study of a gravitational quasi equilibrium thermodynamic approach for establishing and signifying a unique behavior of the cosmological entropy and phase transitions in an expanding Universe. On the basis of prescribed boundary conditions for the cluster temperature a relation for the intra‐cluster medium (ICM) of galaxy clusters has been derived. A more productive and signifying approach of the correlation functions used for galaxy clustering phenomena shows a unique behavior of the entropy change where a phenomenon known as the gravitational phase transition occurs. This unique behavior occurs with a symmetry breaking from mild clustering to low clustering and from mild clustering to high clustering which differs from a normal symmetry breaking in material sciences. We also derive results for the specific latent heat associated with the phase transitions of 3.20 T_c and 0.55 T_c for the mildly clustered phase to the low clustered phase and from the mildly clustered phase to the highly clustered phase, respectively. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Numerical investigation of seismic performance of high modulus columns under earthquake loading     

Demir  Selçuk  Özener  Pelin 《地震工程与工程振动(英文版)》2019,18(4):811-822

Earthquake Engineering and Engineering Vibration - This paper presents the result of two-dimensional finite element modeling studies in order to investigate the seismic behavior of high modulus...  相似文献   

Statistical analysis of methane explosions in Turkey’s underground coal mines and some recommendations for the prevention of these accidents: 2010–2017     

Dursun  Arif Emre 《Natural Hazards》2020,100(1):329-343

Natural Hazards - There is an increased risk in post-fire debris flow (DF) occurrences in the western USA with recent increase in wildfire frequencies. DFs are destructive, causing high loss to...  相似文献   

Prediction of Chemical Oxygen Demand (COD) Based on Wavelet Decomposition and Neural Networks     

Davut Hanbay  Ibrahim Turkoglu  Yakup Demir 《洁净——土壤、空气、水》2007,35(3):250-254

The chemical oxygen demand (COD) parameter of a wastewater treatment plant is predicted based on wavelet decomposition, entropy, and neural networks (NN) for rapid COD analysis. This paper also describes the usage of wavelet and NNs for parameter prediction. Data from a wastewater treatment plant in Malatya, Turkey, were used. This dataset consists of daily values of influents and effluents for a year. To reduce the dimension of input parameters and to decrease the NN training time, wavelet decomposition and entropy were used. Test results were presented graphically. The test results of the trained model were found to be closer to the measured COD values.  相似文献   

An obliquity-controlled Early Pleistocene river terrace record from Western Turkey?     

Darrel Maddy  Tuncer Demir  David R. Bridgland  Antonie Veldkamp  Chris Stemerdink  Tim van der Schriek  Rob Westaway 《Quaternary Research》2005,63(3):66-346

Investigation of the Pleistocene sequence of the Gediz River, Western Turkey, has revealed a record of Early Pleistocene river terraces. Eleven terraces spanning the interval from 1.67 to 1.245 million years ago (MIS 59–37) are preserved beneath basaltic lava flows. The high number of terraces over this short time period reflects high-frequency sedimentation/incision cycles preserved due to the fortuitous combination of relatively high uplift rates (0.16 mm yr⁻¹) and progressive southwards valley migration. Comparison of this record with ODP967 from the Eastern Mediterranean Basin suggests a link between the production of terraces and obliquity-driven 41,000 year climate cycles in the Early Pleistocene.  相似文献   

Landslide susceptibility mapping by frequency ratio and logistic regression methods: an example from Niksar–Resadiye (Tokat,Turkey)     

Gokhan Demir  Mustafa Aytekin  Aykut Akgun 《Arabian Journal of Geosciences》2015,8(3):1801-1812

Turkey confronts loss of life and large economic losses due to natural disasters caused by its morphologic structure, geographical placement, and climate characteristics. The Kuzulu (Koyulhisar) landslide, which caused loss of life and property on 17th March 2005, occurred in an area near the country’s most important active fault, the North Anatolian Fault Zone. To mitigate and prevent landslide damages, prediction of landslide susceptibility areas based on probabilistic methods has a great importance. The purpose of this study was to produce a landslide susceptibility map by the logistic regression and frequency ratio methodologies for a 733-km² area near the North Anatolian Fault Zone from the southeast of Niksar to Resadiye in Tokat province. Conditioning parameters, such as elevation, slope gradient, slope aspect, distance to streams, roads, and faults, drainage density, and fault density, were used in the analysis. Before susceptibility analysis, the landslides observed in the area were separated into two groups for use in analysis and verification, respectively. The susceptibility maps produced had five different susceptibility classes such as very low, low, moderate, high, and very high. To test the performance of the susceptibility maps, area under curve (AUC) approach was used. For the logistic regression method, the AUC value was 0.708; while for the frequency rate method, this value was 0.744. According to these AUC values, it could be concluded that the two landslide susceptibility maps obtained were successful.  相似文献   

Application of electrical resistivity to map the stratigraphy and salinity of fluvio-deltaic aquifers: case studies from Bangladesh that reveal benefits and pitfalls     

Pedrazas  Micaela N.  Cardenas  M. Bayani  Hosain  Alamgir  Demir  Cansu  Ahmed  Kazi Matin  Akhter  Syed Humayun  Wang  Lichun  Datta  Saugata  Knappett  Peter S. K. 《Hydrogeology Journal》2021,29(4):1601-1610

Fluvio-deltaic aquifers are the primary source of drinking water for the people of Bangladesh. Such aquifers, which comprise the Ganges-Brahmaputra-Meghna Delta, are hydrogeologically heterogeneous. Because of widespread groundwater quality issues in Bangladesh, it is crucial to know the hydrostratigraphic architecture and hydrochemistry, as some aquifer units are contaminated, whereas others are safe. Geophysical methods provide a potentially effective and noninvasive method for extensive characterization of these aquifers. This study applies and investigates the limitations of using electrical resistivity imaging (ERI) for mapping the hydrostratigraphy and salinity of an aquifer-aquitard system adjacent to the Meghna River. Some electrical resistivity (ER) sections showed excellent correlation between resistivity and grain size. These suggest that ERI is a powerful tool for mapping internal aquifer architecture and their boundaries with finer-grained aquitards which clearly appear as low-ER zones. However, in parts of some ER sections, variations in electrical properties were determined by porewater resistivity. In these cases, low ER was indicative of brine and did not indicate the presence of finer-grained materials such as silt or clay. Accordingly, the following hydrostratigraphic zones with different resistivities were detected: (1) aquifers saturated with fresh groundwater, (2) a regional silt/clay aquitard, and (3) a deeper brine-saturated formation. In addition, shallow silt/clay pockets were detected close to the river and below the vadose zone. ERI is thus a promising technique for mapping aquifers versus aquitards; however, the observations are easily confounded by porewater salinity. In such cases, borehole information and groundwater salinity measurements are necessary for ground-truthing.

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Automated Detection of 3D Roof Planes from Lidar Data     

Nusret Demir 《Journal of the Indian Society of Remote Sensing》2018,46(8):1265-1272

The purpose of this study is to derive vectoral 3D roof planes from the LIDAR point cloud of the detected buildings. For segmentation of the LIDAR point cloud, the RANSAC algorithm has been used. Because the RANSAC algorithm is sensitive to the used parameters, and results in over- or under-segmentation of the clusters, a refinement method has been proposed. The detection of roof planes has been improved with use of the refinement method. Therefore, similar plane surfaces have been combined, followed by the region-growing algorithm, to split the under-segmented plane surfaces. The digitization of the roof boundaries is performed using the alpha-shapes algorithm, followed by line fitting to generalize the roof edges. The quality assessment has been done using the reference vector dataset with comparison using four different criteria.  相似文献