Comparison of the performances of ground filtering algorithms and DTM generation from a UAV-based point cloud     

Cigdem Serifoglu Yilmaz  Oguz Gungor 《国际地球制图》2018,33(5):522-537

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Impact of climate change on runoff in the upper part of the Euphrates basin     

A. G. Yilmaz 《水文科学杂志》2013,58(7):1265-1279

Abstract

Among the processes most affected by global warming are the hydrological cycle and water resources. Regions where the majority of runoff consists of snowmelt are very sensitive to climate change. It is significant to express the relationship between climate change and snow hydrology and it is imperative to perform climate change impact studies on snow hydrology at global and regional scales. Climate change impacts on the mountainous Upper Euphrates Basin were investigated in this paper. First, historical data trend analysis of significant hydro-meteorological data is presented. Available future climate data are then explained, and, finally, future climate data are used in hydrological models, which are calibrated and validated using historical hydro-meteorological data, and future streamflow is projected for the period 2070–2100. The hydrological model outcomes indicate substantial runoff decreases in summer and spring season runoff, which will have significant consequences on water sectors in the Euphrates Basin.

Citation Yilmaz, A.G. & Imteaz, M.A. (2011) Impact of climate change on runoff in the upper part of the Euphrates basin. Hydrol. Sci. J. 56(7), 1265–1279.  相似文献   

Relevance of building site categories implementation into the land use plan in underground mining area in the region of Petrvald (Czech Republic)     

Marian Marschalko  Isik Yilmaz  Martin Bednárik  Karel Kubečka  Hynek Lahuta 《Environmental Earth Sciences》2014,72(9):3443-3456

Deep mining of mineral resources causes extensive changes in rock environment and ground morphology and must be considered in the land use planning. Subsidence as a result of underground mining activities in terrains is one of the serious geological hazards because they can effect slopes and damage engineering structures, settlement areas, natural lakes and allow infiltration of contaminant into the groundwater. The main aim of this article was implementation of the building site categories of underground mining regions into the land use plans. This case study area was selected from the region of Orlova town within the Ostrava-Karvina Coal district, and this region is one of the most affected areas by underground mining of black coal in the Czech Republic. Certain risk categories of land, where the individual categories express generalized influence of deep mining of coal in current and planned constructions were also represented in this article. Extensive variations caused by underground mining were identified within a wide variability of risk categories. An important finding was also the extensive variability over time, manifested by spatial variations in the stated categories in the studied time periods. Moreover, technical documentation of environmental impacts related to underground mining activities was provided; importance of existing and proposed underground mining projects that may significantly impact the land use was discussed and pointed out in this article, especially.  相似文献   

Analyzing radar rainfall estimate errors with three vector norms: application to weather radar rainfall data in Muğla,Turkey     

Ozkaya  Arzu  Yilmaz  A. Egemen 《Theoretical and Applied Climatology》2022,149(1-2):103-117

Theoretical and Applied Climatology - Over the past several decades, weather radar has become an indispensable tool in flood forecasting studies, especially in ungauged regions. However, the...  相似文献   

Artificial neural network prediction of sulfate and SAR in an unconfined aquifer in southeastern Turkey     

M. Irfan Yesilnacar  Erkan Sahinkaya 《Environmental Earth Sciences》2012,67(4):1111-1119

In many rural communities, groundwater is used to meet the water demand of the community and for the irrigation of cultivating areas. The quality of groundwater can be adversely affected by agricultural activities and finally groundwater quality may become unsuitable for human consumption and irrigation, as in the Harran Plain. Hence, monitoring groundwater quality by cost-effective techniques is necessary, as especially unconfined aquifers are vulnerable to contamination. This study presents an artificial neural network model predicting sodium adsorption ratio (SAR) and sulfate concentration in the unconfined aquifer of the Harran Plain. Samples from 24 observation wells were analyzed monthly for 1?year. Electrical conductivity, pH, groundwater level, temperature, total hardness and chloride were used as input parameters in the predictions. The best back-propagation (BP) algorithm and neuron numbers were determined for the optimization of the model architecture. The Levenberg?CMarquardt algorithm was selected as the best of 12 BP algorithms and optimal neuron number was determined as 20 for both parameters. The model tracked the experimental data very closely both for SAR (R?=?0.96) and sulfate (R?=?0.98). Hence, it is possible to manage groundwater resources in a more cost-effective and easier way with the proposed model application.  相似文献   

Determination of actual limit angles to the surface and their comparison with the empirical values in the Upper Silesian Basin (Czech Republic)     

Marian Marschalko  Işık Yilmaz  Veronika Křístková  Matěj Fuka  Martin Bednarik  Karel Kubečka 《Engineering Geology》2012

This study deals with the determination of the actual limit angles in the long-term formed subsidence basin in the Czech part of the Upper Silesian Basin (the remaining part lays in Poland). Here there was the most extensive underground exploitation of black coal in the north-east of the Czech Republic. A limit angle is absolutely decisive in the determination of deep mining influences in relation to the current and future utilisation of this territory. The two CSM and Paskov mine localities on the edge of the subsidence basin were selected for this study, since they could not have been affected by mining in neighbouring mines. On the grounds of the long-term levelling monitoring of points on the surface which started prior to mining, the horizontal distance between the mined out area and the undisturbed ground surface was identified. The impact of limit angle on the surface was calculated by means of the horizontal distance and the established mining depth. Such identified actual limit angles reached the values of 36° at the CSM Mine and 25° for the Paskov Mine. The calculated values are significantly lower when compared with the currently applied empirical values of 57° for the CSM Mine and 56° for the Paskov Mine. This means that the extent of the undermining effects is unambiguously wider by 611 m at the CSM Mine and by 883 m at the Paskov Mine. This study thus establishes the existence of a significantly vaster area influenced by coal deep mining than previously expected. The identified facts lead to the conclusion that regular revisions and follow-up updates of the empirically determined parameters are recommended.  相似文献   

Assessment of excavatability,abrasivity and slope stability in a sandstone quarry in Istanbul,Turkey     

Selman Er  Murat Yilmaz  Altay Ertin  Atiye Tugrul  Nuray Tokgöz 《Journal of the Geological Society of India》2017,89(5):581-588

The Cebeci region is characterized by outcrops of Carboniferous sandstone, including diabase dykes. This region is very important area for aggregate production in Istanbul, Turkey. The aim of this study is to determine the engineering geological properties of sandstones to assess the excavatability, abrasivity and stability of cut slopes in a quarry site. Firstly, the sandstone samples were used to determine their petrographical and mineralogical characteristics. Then, physico-mechanical tests were performed on these samples. In order to determine rock mass properties, scan-line surveys were performed, and the major orientations of discontinuities were analyzed through the stereographic projection technique. Kinematical analyses were also made to determine the potential failures at the quarry site. According to the results obtained, excavatability is changed from easy ripping to hard ripping on sandstones; the carbonated sandstone is less abrasive than other sandstones. Based on the field studies and stability analyses of the cut slopes, optimum slope geometry and necessary support measures, such as wire mesh and rock fall barriers, are suggested.  相似文献   

Predicting the Building Stone Cutting Rate Based on Rock Properties and Device Pullback Amperage in Quarries Using M5P Model Tree     

S. Najmedin Almasi  Raheb Bagherpour  Reza Mikaeil  Yilmaz Ozcelik  Hamid Kalhori 《Geotechnical and Geological Engineering》2017,35(4):1311-1326

One of the key parameters that affect the selection of equipment and the cost estimation of dimension stone quarries is the rock cutting rate or production rate. In this study, the M5P tree algorithm is used to determine the relationship between the hard rock sawability and its factors especially the physical and mechanical characteristics of rock. To achieve the research goal, a variety of eleven types of hard dimension stone were selected and nine major physical and mechanical characteristics of rock including uniaxial compressive strength, Young’s modulus, Brazilian tensile strength, equivalent quarts content, grain size, Mohs hardness, point load test, density and P-wave velocity of these samples were evaluated. The cutting rate of diamond wire for all of the Workpiece was measured at different pullback amperage with a fully instrumented cutting platform in laboratory. All operational parameters of cutting process were entirely controlled. Thus, a database containing 99 datasets was provided and it has been used for analyses. The obtained results from the pruned and unpruned tree models showed a significant relationship between cutting rate and its factors. In the end, the results of M5P tree method were compared with statistical analyses (i.e., linear and nonlinear regression). The coefficient of determination be equal with 0.92, 0.86, 0.77 and 0.63 for unpruned tree, pruned tree, linear and nonlinear regression method respectively. This comparison showed that the both method of M5P tree technique have a better performance in predicting the cutting rate rather than the statistical regression methods.  相似文献   

Synthesis of Calix[4]arene‐grafted Magnetite Nanoparticles and Evaluation of Their Arsenate as Well as Dichromate Removal Efficiency     

Serkan Sayin  Fatih Ozcan  Mustafa Yilmaz  Ali Tor  Shahabuddin Memon  Yunus Cengeloglu 《洁净——土壤、空气、水》2010,38(7):639-648

In this study, 5,17‐bis‐[(4‐benzylpiperidine)methyl]‐25,26,27,28‐tetrahydroxy‐calix[4]arene ( 3 ) has been prepared by the treatment of calix[4]arene with a secondary amine (4‐benzylpiperidine) and formaldehyde by means of Mannich reaction. The prepared Mannich base ( 3 ) has been grafted onto [3‐(2,3‐epoxypropoxy)‐propyl]‐trimethoxysilane‐modified Fe₃O₄ magnetite nanoparticles (EPPTMS‐MN) in order to obtain 5,17‐bis‐[(4‐benzylpiperidine)methyl]‐25,26,27,28‐tetrahydroxy calix[4]arene‐grafted EPPTMS‐MN (BP‐calix[4]arene‐grafted Fe₃O₄). All new compounds were characterized by a combination of FTIR and ¹H‐NMR analyses. The morphology of the magnetic nanoparticles was examined by transmission electron microscopy. Moreover, the studies regarding the removal of arsenate and dichromate ions from the aqueous solutions were also carried out by using 5,17‐bis‐[(4‐benzylpiperidine)methyl]‐25,26,27,28‐tetrahydroxy‐calix[4]arene in liquid–liquid extraction and BP‐calix[4]arene‐grafted Fe₃O₄ ( 4 ) in solid–liquid extraction experiments. The extraction results indicated that 3 is protonated at proton‐switchable binding sites in acidic conditions. Hence, facilitating binding of arsenate and dichromate is resulted from both electrostatic interactions and hydrogen bonding. To understand the selectivity of 3 , the retention of dichromate anions in the presence of Cl⁻, NO, and SO anions at pH 1.5 was also examined.  相似文献   

Enhancing the Performance of Anaerobic Digestion of Dairy Manure through Phase‐Separation     

Vedat Yilmaz  Göksel N. Demirer 《洁净——土壤、空气、水》2008,36(9):760-766

Anaerobic digestion (AD) is an effective way to convert animal manures into profitable by‐products while simultaneously reducing the pollution of water, air, and soil caused by these wastes. Conventional high‐rate anaerobic reactors cannot effectively process animal manures with high solids‐containing wastes. The two‐phase configuration for AD has several advantages over conventional one‐phase processes, e. g., increased stability of the process, smaller size and cost efficient process configurations. In the present study, the experiments were carried out in a two‐phase system composed of an acidogenic reactor and a methanogenic reactor, and in a one‐phase system composed of only a methanogenic reactor. The reactors were operated as unmixed (without an external mixing aid), unsophisticated, and daily‐fed mode. It was found that the two‐phase configuration was more efficient than the one‐phase system. The biogas production in the two‐phase system at a hydraulic retention time (HRT) of 8.6 days (only methanogenic phase) was calculated to be 42% higher at an organic loading rate (OLR) of 3.5 g VS/L·day than that of the one‐phase with a HRT of 20 days. This translates into significant performance improvement and reduced volume requirement. This finding represents a further step in the achievement of wider use of simple anaerobic reactor configurations for waste treatment in rural areas.  相似文献