Automated 1D interpretation of resistivity soundings by simultaneous use of the direct and iterative methods*     

Ahmet T. Baokur 《Geophysical Prospecting》1999,47(2):149-177

Noise contamination of measured data greatly affects the final results of inversion. Three types of noise source — random and systematic errors and the uncertainties due to the inadequacy of the mathematical model in representing the actual physical conditions — are discussed in the framework of resistivity sounding data. Two methods are proposed for describing these uncertainties. The first possibility is to smooth the measured data by a combination of simple fitting functions that satisfies the ‘1D smoothness’ criteria and consequently simulates the behaviour of a 1D Schlumberger apparent resistivity curve. The second method is to derive weight coefficients from the differences between the measured and the smoothed data sets. Both methods are carried out under the control of the interpreter. The relative merits and drawbacks of the direct and iterative interpretation methods used for the estimation of the parameters of the layered earth model are summarized. Two variants of the combination of these methods are presented to obtain more powerful and automatic interpretation schemes. In the sequential interpretation, an initial guess supplied by the direct method is improved by the iterative method to obtain a reasonable fit between the measured data and the model response. In the simultaneous interpretation, the successive application of the direct and iterative methods is carried out, starting from the first branch of the apparent resistivity curve. The operation is then shifted to subsequent branches that represent the deeper parts of the geoelectric section. This is similar to the data acquisition applied in direct current sounding in which the depth penetration is increased by expanding the current electrode spacings. The proposed sequential and simultaneous interpretation algorithms require minimum aids and efforts of the interpreter.  相似文献   

Nonlinear meta-models for conceptual seakeeping design of fishing vessels     

Ayla Sayli  Ahmet Dursun Alkan  Onur Ganiler 《Ocean Engineering》2010,37(8-9):730-741

The scope of this paper is to develop the nonlinear meta-models for seakeeping behaviour, considering the fishing vessels. These models are intended to be inserted either in a multiattribute design selection process or in a comprehensive multiobjective optimization procedure. For this purpose, seakeeping data of fishing vessels in regular head waves are used to develop meta-models of transfer functions of heave, pitch and vertical acceleration by nonlinear analysis. A home-made software considers two databases; the first is composed by the ship dimensions and coefficients of fishing vessels, and the second is their ship motion data obtained by employing a strip-theory calculation. The meta-models are proposed to predict the vertical motion characteristics for given ranges of speed and wave length during the concept design stage. The independent variables are hull size (Δ), main dimensions (L, B, T), and some hydrostatic parameters (C_WP, C_VP, LCB, LCF, etc.). The results estimated by the software show good correspondences with the ones achieved by direct computations. The study provides additional insight on the influence of hull form parameters on seakeeping performance of small vessels having form properties and parametric range corresponding to the investigated vessels.  相似文献   

A technique for improving MODIS standard snow products for snow cover monitoring over Eastern Turkey     

Yaşar Tekeli  Ahmet Emre Tekeli 《Arabian Journal of Geosciences》2012,5(2):353-363

Daily snow cover maps at 500 m resolution are available from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on NASA's Terra and Aqua satellites. However, information of the ground can only be obtained during clear sky conditions. In addition, the spectral similarity between clouds and snow in the visible part of the spectrum causes some ambiguities in separation of them. The dynamic behavior of clouds with their tendency to move faster often enables discrimination between cloud and snow, since snow remains relatively stationary. In this study, a daily merging methodology to combine Terra and Aqua based snow maps are proposed, and the benefits of this combination are evaluated. The methodology was tested for Eastern Turkey covering the period from December 2002 to March 2003. Merged maps derived from the standard daily snow maps from Terra (MOD10A1) and Aqua (MYD10A1) reduce the cloud cover present in any one image alone, provide better representation of the surface snow cover, and indicate better agreement with ground snow measurements than when either one is used alone. For “on the ground data date” analyses yielded 31% match ratios for MOD10A1 and MYD10A1, whereas combined images enabled 38%. One- to 2-day temporal window shifting enabled further 7% and 5% improvements in match ratios, respectively. The maximum improvement of 25% was achieved in January of 2003. The proposed methodology provides an easy and effective way to improve snow cover maps with little effort and provides fewer cloud-contaminated images for snow monitoring, for hydrology, and water resource management.  相似文献   

Biodegradability Assessment and Treatability of High Strength Complex Industrial Park Wastewater     

Ahmet Baban 《洁净——土壤、空气、水》2013,41(10):976-983

Industrial park wastewater (IPWW) includes complex non‐biodegradable organic compounds. A wastewater treatability study using biodegradability assessment approach was carried out for an industrial park housing mainly textile and machinery sectors. Biodegradable and inert chemical oxygen demand (COD) fractions with soluble and particulate counterparts were experimentally estimated by implementing respirometric methods. Aerobic batch test methods and oxygen uptake rate profiles were used to map kinetic parameters and COD fractions. Denitrification potential was also determined by application of anoxic batch tests. Relevant kinetic constants, stoichiometric, and design parameters were determined for biological processes. Tests were carried out for raw and physico‐chemically pre‐treated IPWW. Hence, it was aimed to assess the effects and necessity of pre‐treatment on biological processes. Biological mineralization, nitrification, and denitrification processes were also designed and tested using a bench scale continuous treatment model for pre‐treated IPWW. The sum of initial inert soluble COD fraction and production of soluble microbial products decreased about 25% for the case of pre‐treated IPWW as compared to raw IPWW. Eighty‐three percent total COD and 89% total Kjeldahl nitrogen removal efficiencies were attained for the modeling experiments of pre‐treated IPWW. Results showed the significance of pre‐treatment if complex strength industrial wastewaters are to be biologically treated.  相似文献   

Impact of mass movements in the Kocaeli Province,Turkey     

Ahmet Karakaş  Özkan Coruk 《Geology Today》2011,27(2):70-73

Recent mass movements in the Kocaeli Province, Turkey in 2010 caused damage to people, property and infrastructure, especially in Izmit and its vicinity. The causes and impact of these mass movements are outlined, so as to increase awareness of their dangerous aspects. Some of these mass movement events took place in urban areas, bringing attention to the need for better and more effective land use practices. The impact of these movements indicates the benefit there would be from geology and engineering geology in the planning of any property development and land use.  相似文献   

A study of residuals for strong ground motions in Adapazari basin,NW Turkey,by ground motion prediction equations (GMPEs)     

Ergin Ulutaş  Özkan Coruk  Ahmet Karakaş 《Studia Geophysica et Geodaetica》2011,55(2):213-240

The city of Adapazarı — located in the Marmara Region of northwest Turkey — is situated on a deep sedimentary basin and was the city most heavily damaged by the strong ground motion of the 17 August 1999 Kocaeli earthquake (moment magnitude M_w = 7.4). This study determines site amplifications of the attenuation relationships for shallow earthquakes in the Adapazarı basin by using the previous ground motion prediction equations (GMPEs) and the traditional spectral ratio method. The site amplifications are determined empirically by averaging the residuals between the observed and predicted peak ground acceleration (PGA) and spectral acceleration (SA) values for various periods. Residuals are significantly correlated with the known characteristics of geological units. A new attenuation model has also been developed for 5% damped spectral acceleration to determine the dependence of strong ground motions on frequency.  相似文献   

Erratum to: Assessment of potential seismic hazard and site effect in Antakya (Hatay Province), SE Turkey     

Semir Över  Aydın Büyüksaraç  Özcan Bektas  Ahmet Filazi 《Environmental Earth Sciences》2011,62(2):327-327

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Astrometric Solution of the Multiple System Xy Leo     

Volkan Bakis  Ahmet Erdem  Edwin Budding  Osman Demircan  Hicran Bakis 《Astrophysics and Space Science》2005,296(1-4):131-134

An astrometric solution, together with time of minimum analysis, has been made for the multiple system XY Leonis (HIP 49136) to identify the properties of the remote companion to the eclipsing pair (AB). From this solution, we derive the inclination of the wide orbit (AB-cd) as 94.4^∘± 0.2^∘, angle of nodes as 247.3^∘± 0.2^∘, and the mass of the wide component (the dwarf binary cd) as 0.98 ± 0.2 M_⊙. This study confirms that the light travel time effect can explain the sinusoidal O−C variation of the eclipsing system.  相似文献   

Biomonitoring of heavy metals by <Emphasis Type="Italic">Pseudevernia furfuracea</Emphasis> (L.) Zopf in Ankara (Turkey)     

Atila Yildiz  Ahmet Aksoy  Gul Nilhan Tug  Cemil Islek  Dilek Demirezen 《Journal of Atmospheric Chemistry》2008,60(1):71-81

The objective of this study was to determine the air pollution level of Ankara and to generate the air pollution map of this city by using Pseudevernia furfuracea (L.) Zopf as a biomonitor. Lichen samples were collected from unpolluted area at Yaprakli Mountains, Cankiri in November 2002 and transplanted to 27 localities in Ankara. Lichen samples were retrieved following an exposure of 3 and 6 months. Heavy metal, Cu, Mn, Ni, Pb and Zn, contents were determined by using inductively coupled plasma spectrometry (ICP). The chlorophyll a and b contents were determined by using DMSO method. The increase in Ni, Pb, Zn and chlorophyll a content of the specimens were statistically important. All the increases and decreases in the variables could be explained by the environmental stress like pollution, but it is hard to say that this is the only reason of these changes, also climatic conditions, seasons, strength of the light and the physiological status of the plant itself effective on these changes. According to the results of heavy metal analysis Pseudevernia furfuracea continued to accumulate heavy metals and worked well as a biomonitor. The air pollution level of Ankara shows great variations because of the great area of the city.  相似文献   

Visualization of geotechnical data by means of geographic information system: a case study in Eskisehir city (NW Turkey)   总被引：2，自引：2，他引：0  

Ahmet Orhan  Hasan Tosun 《Environmental Earth Sciences》2010,61(3):455-465

Recently, geographic information system Software’s are widely used in engineering geology applications. Such a study was performed in the Eskisehir urban area of about 30 km² via geo-engineering maps, cross-sections and panel-block diagrams, which are formed to predict the properties of foundation soil. In order to determine the engineering geology properties of the region, physical and mechanical characteristics of the soil profile were tested on 1,011 disturbed and 383 undisturbed samples from a total of 170 boreholes. Topographic, lithological and geotechnical data of the region were compiled as a database in computer. Five geological cross-sections were drawn to decipher specifically the alluvial deposits in detail in densely populated areas. Hence, geological characteristics of the area were evaluated in a three-dimensional mode. Five standard penetration test (SPT) cross-sections at the same directions and SPT, uniaxial compressive strength (qu) and soil class Zonation maps were produced at different depths and panel-block diagrams were also created to define the geo-engineering properties of the investigation area. In this respect, the sub-surface of the study area is fully visualized and useful predictor maps, cross-sections and panel-block diagrams are performed to be used in further studies.  相似文献