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11.
Burak Aydog˘an Berna Ayat Mehmet N. Öztürk Esin Özkan Çevik Yalçın Yüksel 《Ocean Engineering》2010,37(5-6):443-453
Owing to their complex character, modeling flow patterns of narrow straits has always been a challenge, even with the numerical techniques of today. This study was aimed at predicting vertical current profiles of a given point in a narrow strait, the Strait of Istanbul. On account of the speed and simplicity it offers, and of its remarkable success in solving complex problems, the feed forward back propagation (FFBP) artificial neural network (ANN) technique was chosen for this study. The model was built on 7039 hours of concurrent measurements of current profiles, meteorological conditions, and surface elevations. The model predicted 12 outputs of East and North velocity components at different depths in a given location. Various alternative models with different inputs and neuron numbers were evaluated attaining the best model by trial and error. Predictions from proposed ANN model were in accordance with the observations with average root mean square error of 0.16 m/s. The same input parameters were then used to build models that predicted current velocities 1–12 h into the future. Results of these predictions show good overall agreement with observations and that FFBP ANN can be used as a reliable tool for forecasting current profiles in straits. 相似文献
12.
Esin Sipahi 《New Astronomy》2012,17(4):383-387
New multi-colour UBVR light curves of the eclipsing binary KR Cyg were obtained in 2005. Photometric solutions were derived using the Wilson-Devinney method. The result shows that KR Cyg is a near-contact binary system with a large effective temperature difference between the components, approximately 5230 K. All the times of minimum light were collected and combined with our observations obtained in 2010 and 2011. Analysing all the times of mid-eclipse, we found for the first time a possible periodic oscillation with an amplitude of 0.001 days and a period of ∼76 years. The periodic oscillation could be explained by the light-time effect due to a presumed third component. 相似文献
13.
Klaus Peter Jochum Uwe Nohl Kirstin Herwig Esin Lammel Brigitte Stoll Albrecht W. Hofmann 《Geostandards and Geoanalytical Research》2005,29(3):333-338
We have developed a new database named GeoReM ( http://georem.mpch-mainz.gwdg.de ) for reference materials and isotopic standards of geochemical and mineralogical interest. Reference samples include rock powders originating from the USGS, GSJ, GIT-IWG, synthetic and natural reference glasses originating from NIST, USGS, MPI-DING, as well as mineral (e.g., 91500 zircon), isotopic (e.g., La Jolla, E&A, NIST SRM 981), river water and seawater reference materials. GeoReM is a relational database, which strongly follows the concept of the three EARTHCHEM databases. It contains published analytical and compilation values (major and trace element concentrations, radiogenic and stable isotope ratios), important metadata about the analytical values, such as uncertainty, uncertainty type, method and laboratory. Sample information and references are also included. Three different ways of interrogating the database are possible: (1) sample names or material types, (2) chemical criteria and (3) bibliography. Some typical applications are described. GeoReM currently (October 2005) contains more than 750 geological reference materials, 6000 individual sets of results and references to 650 publications. 相似文献
14.
Neşer G Kontas A Unsalan D Altay O Darılmaz E Uluturhan E Küçüksezgin F Tekoğul N Yercan F 《Marine pollution bulletin》2012,64(5):1055-1059
Alia?a Bay is one of the most important maritime zones of Turkey where shipping activity, shipbreaking industry, steel works and petrochemical complexes exist together. Polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons in sediment of the Alia?a Bay were investigated to evaluate an environmental risk assessment from PAHs contamination in 2009-2010. Aliphatic and PAHs diagnostic ratios were showed to be mainly petroleum-originated and pyrolitic contaminations, respectively. The TEL/PEL analysis suggests that Alia?a sediments were likely to be contaminated by acutely toxic PAH compounds. 相似文献
15.
Sediment concentrations of heavy metals in the Homa Lagoon (Eastern Aegean Sea): Assessment of contamination and ecological risks 总被引：8，自引：0，他引：8
The concentrations of heavy metals and organic carbon in sediment of the Homa Lagoon which is one of the most productive lagoons and commercial important active fish trap in the Eastern Aegean Sea, were investigated in order to describe the temporal and spatial distributions of metals. These results were used to evaluate possible ecological risks that could be a problem for the environment of the lagoon in the future. Sediments were enriched with Cr, Ni and considered as heavily polluted per the SQG. The Cf of Ni and Cr were presented moderate level of contamination in this area. The Cd levels indicated moderate degree of contamination at station B, C, D and E due to agricultural drainage water, industrial and domestic wastewater, are transported by the Gediz River. Sediments from Homa Lagoon were most toxic for Ni due to exceedances of the TEL and PEL values. 相似文献
16.
Kubilay Cihan Yalcin YukselMehmet Berilgen Esin Ozkan Cevik 《Soil Dynamics and Earthquake Engineering》2012,34(1):1-10
Rubble-mound breakwaters are subjected not only to water wave action but also to other types of environmental loading, such as earthquakes. The design of coastal structures should take into account the most relevant factors in each case, including seismic loading. The purpose of this study is to understand the dynamic response of breakwater materials in dry and water conditions. Hence, an experimental study was carried out for homogeneous breakwater structures subjected to different dynamic loadings with variable frequencies and amplitudes in a shaking tank. A shaking tank with a single degree of freedom was developed. The experiments were performed with rigid bottom conditions. The model scale was 1/50. The cyclic responses of the breakwater made of entirely armor material and another of entirely core material were examined separately, and their behaviors were then compared. The experimental results are also discussed with a numerical study, and the material properties and failure modes were thus defined. It is found that the settlement of the armor and core materials under cyclic loads increased with increasing base acceleration level. The cyclic deformation of the rubble mound breakwater in water was larger than that under dry conditions. The cyclic deformation of the rubble materials resulted in crest lowering and slumping. Dominant mode of the seismic failure was associated with the settlement of the crown of the structure accompanied by densification of the core material. 相似文献
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18.
Esin Sipahi 《New Astronomy》2012,17(3):377-381
We present CCD photometric observations of the slow irregular type variable KU Her. We have also used observations from the ASAS Database and the AAVSO International Database. The V-band observations span eight years from August of 2002 to September of 2010. The length and density of the data enable us to look for variations on time scales ranging from days to years. The V-band observations of KU Her are analysed to derive periodicity. This analysis was an approach to find the fundamental periods of the variability of KU Her. Analysis of the KU Her light variation indicates a complex combination of different periods. Five main and three harmonic periods are identified. In addition to the period analysis, we present the colour variations of the star. 相似文献
19.
Hüseyin E. ?elik Gonca Coskun H. Kerem Cigizoglu Necati A??ralio?lu Abdurrahim Ayd?n A. ?lker Esin 《Natural Hazards》2012,63(2):461-477
The climatic and physiographical factors of the Kozdere Creek Watershed are examined to find out the causes of the flood of August 11, 2004. Actual land use has been obtained from forest management stand plans and classified satellite images. The multispectral digital satellite data set belonging to years 1992, 1993, and 2005 was used to determine the status of land use. Physiographic factors, including the slope and the aspect, have been identified from digitized ortho-photo maps in the GIS environment. Since flow records of Kozdere are not available, flow values corresponding to different return periods were obtained using regression analysis of neighboring streams. No noticeable alteration of the land use occurred between 1992 and 2005. Since the physical factors are the same as they were during the 1985 rain, the flood after the 2004 rainfall cannot be due to the physiographical factors of the upper watershed. The existing channel in the neighborhood is not enough to convey even the 10-year return period flow. Thus, the 2004 flow did not fit into this cross-section and flooded houses on the alluvial fan. The cross-section of the Kozdere Creek passing through the PTT neighborhood should be increased, and the surface roughness should be decreased by covering the channel with concrete in order to prevent floods. 相似文献
20.
A mathematical model describing the Black Sea level change in the Late Pleistocene-Holocene is offered. A theoretical curve
for temporal change in the sea level is obtained. It is established that, in the range from 20 to 12 ky BP, the sea level
rose to ∼20 m and fluctuated with various amplitudes and periods. In the range from 12 to 11 ky BP during the Bosphorus Strait
formation, there was a sea regression by 30–50 meters, and level of the Black Sea dropped to the World Ocean level. Further,
it mirrored variation of the ocean level. 相似文献