The effect of the relative humidity and the specific humidity on the determination of the climate regions in Turkey     

Sinan Sahin  H. Kerem Cigizoglu 《Theoretical and Applied Climatology》2013,112(3-4):469-481

All elements of climate that affect climatic events must be taken into account such that the climate regions are determined with exactitude. To this end, data on maximum temperature (Tx), minimum temperature (Tn), mean temperature (Tm), and precipitation (Pt) as well as local pressure (Ps), mean wind (WN), relative humidity (RH), and specific humidity (SH) have been investigated statistically and graphically. The specific humidity data calculated using Tm, Ps, and RH data and statistical comparisons have shown that there are no drawbacks to using SH in climatologic studies. According to principal component analysis, it was concluded that RH and SH should be used together with Tx, Tm, Tn, and Pt for the determination of the climate regions. Two cluster analysis methods, Ward's method and Kohonen neural network technique, were used to show the effect of RH and SH. A comparison of the cluster's stability between the limited and high number of stations shows that Ward's method and Kohonen neural network are very stable in both cases. It was also determined that RH does not change the outline of climate regions but that it affects the zones of climate transition. It was observed that clusters determined by using Tm, Pt, and RH provide relatively more distinctive clusters in the data space than clusters determined by using Tm, Pt, and SH.  相似文献   

Evaluation of liquefaction in Karasu River floodplain after the October 23, 2011, Van (Turkey) earthquake     

Akin  Mutluhan  Ozvan  Ali  Akin  Muge K.  Topal  Tamer 《Natural Hazards》2013,69(3):1551-1575

Natural Hazards - The eastern shore of Lake Van was shaken by a powerful earthquake (M w 7.2) on October 23, 2011. The epicenter of the earthquake was located at about 30 km north of the...  相似文献   

The effect of the number of holes on blast-induced ground vibrations     

Sahin Yuvka  Sunay Beyhan  Onder Uysal 《Environmental Earth Sciences》2017,76(17):621

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Modeling of coal bed methane (CBM) production and CO2 sequestration in coal seams     

Ekrem Ozdemir 《International Journal of Coal Geology》2009,77(1-2):145-152

A mathematical model was developed to predict the coal bed methane (CBM) production and carbon dioxide (CO₂) sequestration in a coal seam accounting for the coal seam properties. The model predictions showed that, for a CBM production and dewatering process, the pressure could be reduced from 15.17 MPa to 1.56 MPa and the gas saturation increased up to 50% in 30 years for a 5.4 × 10⁵ m² of coal formation. For the CO₂ sequestration process, the model prediction showed that the CO₂ injection rate was first reduced and then slightly recovered over 3 to 13 years of injection, which was also evidenced by the actual in seam data. The model predictions indicated that the sweeping of the water in front of the CO₂ flood in the cleat porosity could be important on the loss of injectivity. Further model predictions suggested that the injection rate of CO₂ could be about 11 × 10³ m³ per day; the injected CO₂ would reach the production well, which was separated from the injection well by 826 m, in about 30 years. During this period, about 160 × 10⁶ m³ of CO₂ could be stored within a 21.4 × 10⁵ m² of coal seam with a thickness of 3 m.  相似文献   

Flow around circular and noncircular cylinders by a low-order panel method     

Iskender Sahin  Noriaki Okita 《Ocean Engineering》1998,25(7):529-539

Time-dependent cross-flow was studied around cylinders with circular and noncircular cross-sections. The numerical approach for the analysis was a low-order panel method based on constant source and dipole values along each panel. The method was previously used successfully for several applications, such as calculation of the added mass and damping coefficients. In simulating the viscous time-dependent flow around the cylinder, the time-dependent wake feature of the code was used. For the circular and D-cylinders, the results agreed well with the experiments. Suggestions for improving the results for T-cylinders with angle of attack are included.  相似文献   

Landslide susceptibility mapping using GIS-based multi-criteria decision analysis,support vector machines,and logistic regression   总被引：14，自引：3，他引：11  

Taskin Kavzoglu  Emrehan Kutlug Sahin  Ismail Colkesen 《Landslides》2014,11(3):425-439

Identification of landslides and production of landslide susceptibility maps are crucial steps that can help planners, local administrations, and decision makers in disaster planning. Accuracy of the landslide susceptibility maps is important for reducing the losses of life and property. Models used for landslide susceptibility mapping require a combination of various factors describing features of the terrain and meteorological conditions. Many algorithms have been developed and applied in the literature to increase the accuracy of landslide susceptibility maps. In recent years, geographic information system-based multi-criteria decision analyses (MCDA) and support vector regression (SVR) have been successfully applied in the production of landslide susceptibility maps. In this study, the MCDA and SVR methods were employed to assess the shallow landslide susceptibility of Trabzon province (NE Turkey) using lithology, slope, land cover, aspect, topographic wetness index, drainage density, slope length, elevation, and distance to road as input data. Performances of the methods were compared with that of widely used logistic regression model using ROC and success rate curves. Results showed that the MCDA and SVR outperformed the conventional logistic regression method in the mapping of shallow landslides. Therefore, multi-criteria decision method and support vector regression were employed to determine potential landslide zones in the study area.  相似文献   

A newly developed seismic microzonation model of Erbaa (Tokat, Turkey) located on seismically active eastern segment of the North Anatolian Fault Zone (NAFZ)   总被引：1，自引：1，他引：0  

Muge K. Akin  Tamer Topal  Steven L. Kramer 《Natural Hazards》2013,65(3):1411-1442

A methodology to model seismic microzonation maps is required in the hazard mitigation decision plans of the earthquake prone areas. The stage of disaster preparedness for new residential places is of great importance for detailed seismic microzonation models. The effects of local geological and geotechnical site conditions were considered in order to establish site characterization as the initial stage of the models in this study. Dynamic soil properties based on the empirical correlations between shear wave velocity (V _s) and standard penetration test blow counts were taken into account in order to define representative soil profiles extending down to the engineering bedrock. One-dimensional site response analyses were performed to analyze earthquake characteristics on the ground surface. The layers for soil classification, geology, depth to groundwater level, amplification, distance to fault, slope and aspect, and liquefaction-induced ground deformation potential of the study area were prepared in seismic microzonation models. The study area, Erbaa, is placed along the seismically active North Anatolian Fault Zone. Final seismic microzonation map of the study area was evaluated applying different GIS-based Multi-Criteria Decision Analysis (MCDA) techniques. Two of the MCDA techniques, simple additive weighting and analytical hierarchical process (AHP), are considered during the evaluation step of the final seismic microzonation map. The comparison is made in order to distinguish two different maps based on these MCDA techniques. Eventually, AHP-based seismic microzonation map is more preferable for the seismic design purposes in this study.  相似文献   

Use of Reverse Extrusion Method to Determine Undrained Shear Strength     

Kamil Kayabali  Adil Ozdemir 《Geotechnical and Geological Engineering》2013,31(2):719-727

The unconfined compression test (UCT) is one of the most common tools to measure the undrained shear strength of fine-grained soils. Soft to very soft soils often pose problems such that the determination of failure load is unclear using this test. Similarly, fissured clays would endeavor failure along pre-existing planes of weakness. The reverse extrusion test (RET), a mechanical metallurgy tool, has been used recently in some soil mechanics applications. The scope of this investigation is to evaluate the potential of the RET as a substitute for the UCT. Sixty remolded soils and 75 natural soils were subjected to the RET and UCT. Remolded soils were tested on mixtures prepared at the plastic limit. It was found that the ratio of extrusion pressure at failure to the undrained shear strength is relatively consistent and concentrates around 14. The same ratio was found to be 15 for natural soils. The conclusion reached, upon a series of tests on both the remolded and natural soil samples, is that the RET better represents the undrained shear strength of soil than does the UCT, that the practical difficulties with UCT is eliminated by the RET, and the results may be improved by taking into account soil plasticity.  相似文献   

Optimization of constitutive parameters of foundation soils k-means clustering analysis     

Muge Elif Orakoglu  Cevdet Emin Ekinci 《寒旱区科学》2013,5(5):0626-0636

The goal of this study was to optimize the constitutive parameters of foundation soils using a k-means algorithm with clustering analysis. A database was collected from unconfined compression tests, Pr...  相似文献   

Evaluation of equivalent lateral force procedure in estimating seismic isolator displacements   总被引：1，自引：0，他引：1  

Gokhan Ozdemir  Michael C. Constantinou 《Soil Dynamics and Earthquake Engineering》2010

Simplified methods of analysis described in codes and specifications for seismically isolated structures are always used either directly in special cases or for checking the results of nonlinear response history analysis (RHA). In this study, the maximum isolator displacements and base shears determined by nonlinear RHA are compared with those determined by the equivalent lateral force (ELF) procedure in order to assess the accuracy of the simplified method in the case of earthquakes with near field characteristics. Features of this study are that the ground motions used in analysis are selected and scaled using contemporary concepts and that the ground excitation is considered bi-directional. It is shown that the simplified method provides acceptably accurate predictions of shear isolator displacements and shear forces for a range of isolator properties and ground motions representative of stiff and soft soil conditions.  相似文献