A New Polyelectrolyte Dosing Method: Injection into Deep Bed Filter Media     

Ebubekir Yuksel  Murat Eyvaz  Tugrul S. Aktas  Ahmet M. Saatci 《洁净——土壤、空气、水》2011,39(8):750-758

The aim of this paper was to investigate a novel method of polyelectrolyte injection into deep bed filter media. The raw water and the filter media used in the pilot filters were obtained from the Omerli Reservoir that supplies one million m³/day of water to the greater city of Istanbul. A cationic polyelectrolyte was injected at the entrance of the filter and at different depths of the sand bed. The effect of polyelectrolyte injection location and method was evaluated by measuring the effluent turbidity, effluent particle count, and the head losses at different locations of the sand media. It was observed that the simultaneous injection of the polyelectrolyte on top of the filter bed and at the center can lengthen the filter run time while achieving an effluent turbidity as low as 0.06 NTU (nephelometric turbidity unit) and 4 log (99.99%) particle removal.  相似文献   

Snow avalanche incidents in north-western Anatolia,Turkey during December 1992     

Ibrahim Gürer  Harun Tunçel  Ö. Murat Yavaş  Tarhan Erenbılge  Ayhan Sayin 《Natural Hazards》1995,11(1):1-16

Snow avalanches take place in the mountainous regions of Turkey mostly in the eastern Anatolia Region with an average annual death toll of 23 people and much damage to property. However, in the mountainous areas of the Kastamonu and Sinop provinces in the western part of the Black Sea Region of Turkey between 25 and 30 December 1992, blizzards with heavy snowfall caused roof collapses and major avalanche events whereby 16 people were killed and 2 injured. When past records were investigated, there was no evidence that avalanche accidents had been encountered in the region where the dominant precipitation type is rain in the coastal zones and snow over the mountains. Moreover, avalanche prevention measures are so limited that the resettlement of villages or hamlets located in risk zones is common practice. In this article, avalanche formation associated with the meteorological conditions and geomorphologic features is discussed.This study was partially supported by Tübitak (Scientific and Technical Research Council of Turkey) with Project No. YBAG-0067.  相似文献   

Particle Size Distribution Analysis of Chemical Oxygen Demand Fractions with Different Biodegradation Characteristics in Black Water and Gray Water     

Selda Murat Hocaoglu  Derin Orhon 《洁净——土壤、空气、水》2013,41(11):1044-1051

The study investigated the particle size distribution of major organic pollutants in black water and gray water fractions of domestic sewage. Particle size distribution was assessed by means of a filtration/ultrafiltration sequence together with laser diffraction. Emphasis was placed upon the correlation between the size distribution of chemical oxygen demand (COD) and its biodegradation characteristics obtained by respirometric analysis. Particle size distribution analysis provided specific fingerprints for COD, total organic carbon (TOC), carbohydrates, proteins, and color for black water and gray water: Aside from significant difference between COD contents, the more concentrated COD was predominantly in particulate form in black water, whereas soluble COD accounted for nearly 60% of the total in gray water. TOC and carbohydrate exhibited a similar pattern. Size distribution of particulate matter yielded different characteristics for the two fractions and indicated that settleable matter should be considered as a significant portion in assessing biodegradation. Particle size distribution of COD, although not directly related, gave an accurate image of biodegradation, indicating that particle size was basically the main parameter for differentiating and predicting major COD fractions with different biodegradation characteristics. It explained the dual hydrolysis mechanism associated with the black water based on the existence of a significant settleable COD fraction.  相似文献   

Pan-sharpening quality investigation of PLÉIADES-1A images     

Mustafa Ozendi  Huseyin Topan  Murat Oruc  Ali Cam 《国际地球制图》2016,31(8):881-890

Optical remote sensing satellites obtain MS and Pan images simultaneously over the same coverage area. Remote sensing and image processing communities are working on different pan-sharpening methods capable of taking advantage of MS and Pan images. Each remote sensing system has its own advantages and disadvantages, leading to the question ‘Which pan-sharpening method should be used for which type of imagery?’ The aim of this research is to investigate the pan-sharpening performance of PLÉIADES-1A images. For this purpose, pan-sharpened images were generated using PCA, IHS and Brovey Transform which are the most popular pan-sharpening methods. Then, the pan-sharpened images were evaluated quantitatively using Correlation Coefficient, Root Mean Square Error, Relative Average Spectral Error, Spectral Angle Mapper and Erreur Relative Globale Adimensionnelle de Synthése. In addition, pan-sharpened images were evaluated qualitatively by taking object availability and completeness into consideration.  相似文献   

Anatolian surface wave evaluated at GEOFON Station ISP Isparta, Turkey     

Murat Erduran   zcan ak&#x;r  Timur Tezel  akir ahin   mer Alptekin 《Tectonophysics》2007,434(1-4):39-54

We have studied seismic surface waves of 255 shallow regional earthquakes recently recorded at GEOFON station ISP (Isparta, Turkey) and have selected these 52 recordings with high signal-to-noise ratio for further analysis. An attempt was made by the simultaneous use of the Rayleigh and Love surface wave data to interpret the planar crust and uppermost mantle velocity structure beneath the Anatolian plate using a differential least-square inversion technique. The shear-wave velocities near the surface show a gradational change from approximately 2.2 to 3.6 km s^− 1 in the depth range 0–10 km. The mid-crustal depth range indicating a weakly developed low velocity zone has shear-wave velocities around 3.55 km s^− 1. The Moho discontinuity characterizing the crust–mantle velocity transition appears somewhat gradual between the depth range  25–45 km. The surface waves approaching from the northern Anatolia are estimated to travel a crustal thickness of  33 km whilst those from the southwestern Anatolia and part of east Mediterranean Sea indicate a thicker crust at  37 km. The eastern Anatolia events traveled even thicker crust at  41 km. A low sub-Moho velocity is estimated at  4.27 km s^− 1, although consistent with other similar studies in the region. The current velocities are considerably slower than indicated by the Preliminary Reference Earth Model (PREM) in almost all depth ranges.  相似文献   

North Atlantic Oscillation influences on Turkish lake levels     

Murat Küçük  Ercan Kahya  Taner M. Cengiz  Mehmet Karaca 《水文研究》2009,23(6):893-906

The North Atlantic Oscillation (NAO) is a large‐scale mode of natural climate variability governing the path of Atlantic mid‐latitude storm tracks and precipitation regimes in the Atlantic and Mediterranean sectors. The primary focus of this study is to investigate the variability of lake levels in seven lakes scattered across Turkey using the method of continuous wavelet transforms and global spectra. The long winter (December, January, February and March) lake‐level series and the NAO index (NAOI) series were subjected to wavelet transform. The global wavelet spectrum (energy spectrum of periodicities) of lake levels and winter NAOI anomalies, in most cases, revealed a significant correlation. It was shown that the Tuz, Sapanca, and Uluabat lakes reflect much stronger influences of the NAO than the other four lakes. In contrast, weak correlations were found in the coastal areas of the Mediterranean and eastern Turkey. The periodic structures of Turkish lake levels in relation to the NAO revealed a spectrum between the 1‐year and 10‐year scale level. Although the periodicities of more than 10‐year scale levels were detected, explaining significant relations between the NAO and these long‐term periodicities remains a challenging task. The results of this study are consistent with the earlier studies concerning the teleconnection between the NAO and climate variables in Turkey. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Factors controlling the morphological evolution of the Çanakkale Strait (Dardanelles, Turkey)     

Erkan Gökaşan  Mustafa Ergin  Mustafa Özyalvaç  Halil İbrahim Sur  Hüseyin Tur  Tolga Görüm  Timur Ustaömer  Fatma Gül Batuk  Hakan Alp  Halim Birkan  Ahmet Türker  Erhan Gezgin  Murat Özturan 《Geo-Marine Letters》2008,28(2):107-129

Seismic profiling, bathymetric and physical oceanographic data collected from the Çanakkale Strait revealed that the morphological evolution of the strait has been controlled by tectonic activity, and sediment erosion and deposition. Sediments in the strait have been sourced mostly by rivers draining the Biga Peninsula during lowstand periods. In highstand periods, by contrast, deposits in the strait were reworked by currents. The seafloor morphology of the Çanakkale Strait is also controlled by a sequence of factors ranging from tectonics to current erosion and deposition. Channel deposits overlying the basement are being eroded at the narrower, meandering central section of the strait (the Nara Passage) due to high current velocities. The eroded sediments are deposited in the relatively linear and wider, northern and southern sectors of the strait exposed to low current velocities. As a result, the high-energy areas are more deeply incised due to the erosion, whereas deposition elevates the seafloor in the areas exposed to lower current energy. Three strike-slip faults, which possibly relate to the activity of the North Anatolian Fault Zone, are responsible for the irregular shape of the strait and this, in turn, controls the current velocity along the strait. The high-energy conditions probably commenced with the latest invasion of Mediterranean waters some 12 ka b.p., and have continued as a two-layered current system to the present day.  相似文献   

Effect of isolator and ground motion characteristics on the performance of seismic‐isolated bridges     

Murat Dicleli  Srikanth Buddaram 《地震工程与结构动力学》2006,35(2):233-250

This paper presents the effect of isolator and substructure properties as well as the frequency characteristics and intensity of the ground motion on the performance of seismic‐isolated bridges (SIBs) and examines some critical design clauses in the AASHTO Guide Specification for Seismic Isolation Design. For this purpose, a parametric study, involving more than 800 non‐linear time history analyses of simplified structural models representative of typical SIBs, is conducted. The results from the parametric study are then used to derive important design recommendations and conclusions that may be used by bridge engineers to arrive to a more sound and economical design of SIBs. It is found that the SIB response is a function of the peak ground acceleration to peak ground velocity ratio of the ground motion. Thus, the choice of the seismic ground motion according to the characteristics of the bridge site is crucial for a correct design of the SIB. It is also found that the characteristic strength of the isolator may be chosen based on the intensity and frequency characteristics of the ground motion. Furthermore, the isolator post‐elastic stiffness is found to have a notable effect on the response of SIBs. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Slip distribution and stress changes associated with the 1999 November 12, Düzce (Turkey) earthquake  (M_w= 7.1)      

Murat Utkucu  Süleyman S. Nalbant  John McCloskey  Sandy Steacy  Ömer Alptekin 《Geophysical Journal International》2003,153(1):229-241

  相似文献   

Assessment of landslide susceptibility for a landslide-prone area (north of Yenice, NW Turkey) by fuzzy approach   总被引：17，自引：0，他引：17  

Murat Ercanoglu  Candan Gokceoglu 《Environmental Geology》2002,41(6):720-730

. Regional landslide susceptibility assessments pose complex problems. To solve these problems, numerous approaches, such as statistical analysis, geotechnical engineering approach, geomorphologic approach and fuzzy logic, have been employed. However, all the available methods for regional landslide susceptibility assessments have some uncertainties due to a lack of knowledge and variability. Minimizing these uncertainties provides realistic approaches. Use of the fuzzy logic approach to produce a landslide susceptibility map of a landslide-prone area in NW Turkey is the main purpose of the present study. For this purpose, the study includes five main stages, these being the preparation of a landslide inventory of the study area, the application of factor analysis, the extraction of fuzzy if-then rules, the use of a geographical information system, and the control of the reliability of the resulting landslide susceptibility map. Slope angle, slope aspect, land use, weathering depth, water conditions and topographical elevation were considered as landslide conditioning factors for the study area. A total of 23 if-then rules was extracted from the field data. Employing these rules, fuzzified index maps representing each parameter were obtained. Finally, combining these maps, the landslide susceptibility map of the area was prepared. When compared with the landslide susceptibility map, the landslides identified in the area were found to be located in the very high- and high-susceptibility zones. As far as the performance of the fuzzy approach for processing is concerned, the images appear to be quite satisfactory, the zones determined on the map being zones of relative susceptibility.  相似文献