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Ü. Ertan M. A. Alpar M. H. Erkut K. Y. Ekşi Ş. Çalışkan 《Astrophysics and Space Science》2007,308(1-4):73-77
The anomalous X-ray pulsar 4U 0142+61 was recently detected in the mid infrared bands with the SPITZER Observatory (Wang, Chakrabarty and Kaplan: Nature 440, 772 (2006)). This observation is the first instance for a disk around an AXP. From a reanalysis of optical and infrared data, we show that the observations indicate that the disk is likely to be an active disk rather than a passive dust disk beyond the light cylinder, as proposed in the discovering paper. Furthermore, we show that the irradiated accretion disk model can also account for all the optical and infrared observations of the anomalous X-ray pulsars in the persistent state. 相似文献
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Water Resources - The aim of this study is to develop a new trophic level index using water quality parameters which are known to affect eutrophication but not in national and international... 相似文献
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Sorption behavior of Lanaset Red (LR) G on lentil straw (LS) was studied as a function of particle size, adsorbent dose, initial pH value, initial dye concentration, and contact time. Sorption kinetics data was well described by logistic model. Modified logistic equation can be used to explain effects of initial dye concentrations and contact time on the sorption of LR G with high R2 value. Freundlich model was found to be excellent in representing the equilibrium data. Thermodynamic parameters like free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0) were calculated by the use of Langmuir constant. Thermodynamic data showed that the sorption processes were spontaneous and endothermic in nature. Desorption process suggested that strong binding and weak interactions could be formed between adsorbent surface and dye molecules. Results revealed that LS has a remarkable potential for the sorption of LR G. 相似文献
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Ahmet Can Altunişik Alemdar Bayraktar Barış Sevim Şevket Ateş 《Soil Dynamics and Earthquake Engineering》2011
This paper describes ambient vibration based seismic evaluation procedure of an isolated highway bridge. The procedure includes finite element modeling, ambient vibration testing, finite element model updating and time history analysis. Gülburnu Highway Bridge located on the Giresun–Espiye state highway is selected as a case study. Three dimensional finite element model of the bridge is created by SAP2000 software to determine the dynamic characteristics analytically. Since input force is not measured, Operational Modal Analysis is applied to identify dynamic characteristics. Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification methods are used to obtain experimental dynamic characteristics. Analytical and experimental dynamic characteristic are compared with each other and finite element model of the bridge is updated by changing of material properties to reduce the differences between the results. Analytical model of the bridge after model updating is analyzed using 1992 Erzincan earthquake record to determine the seismic behavior. EW, NS and UP components of the ground motion are applied to the bridge at the longitudinal, transverse and vertical directions, respectively. It is demonstrated that the ambient vibration measurements are enough to identify the most significant modes of highway bridges. Maximum differences between the natural frequencies are reduced averagely from 9% to 2% by model updating. It is seen from the earthquake analyses that friction pendulum isolators are very effective in reducing the displacements and internal forces. 相似文献
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F. Ekmekçi A. Elmaslı M. Yılmaz T. Kılıçoğlu T. Tanrıverdi Ö. Baştürk H.V. Şenavcı Ş. Çalışkan B. Albayrak S.O. Selam 《New Astronomy》2012,17(7):603-609
With the aim of providing new and up-to-date absolute parameters of some close binary systems, new BVR CCD photometry was carried out at the Ankara University Observatory (AUG) for five eclipsing binaries, ET Boo, V1123 Tau, V1191 Cyg, V1073 Cyg and V357 Peg between April, 2007 and October, 2008. In this paper, we present the orbital solutions for these systems obtained by simultaneous light and radial velocity curve analyses. Extensive orbital solution and absolute parameters for ET Boo system were given for the first time through this study. According to the analyses, ET Boo is a detached binary while the parameters of four remaining systems are consistent with the nature of contact binaries. The evolutionary status of the components of these systems are also discussed by referring to their absolute parameters found in this study. 相似文献
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This study reported the mass mortality events (MMEs) of Pinna nobilis based on diving surveys in Turkey. Data were collected across 12 sites in the Aegean Sea, and one site in the Sea of Marmara, within the period of June-September 2019. The results showed that a low mortality rate of 10% was found in the Sea of Marmara, and a MME was not detected for this area. In contrast, 97% mortality was recorded for the P. nobilis population distributed in the Turkish Aegean Sea. This discrepancy might be related to the seawater temperature and salinity values of these two seas. The waters of the Sea of Marmara were colder and less salty than the Aegean Sea. The findings highlighted the importance of protecting the healthy population of critically endangered fan mussels in the Sea of Marmara. It was recommended that sound management plans comprising of monitoring, enforcement and public awareness activities could be implemented in order to achieve this. 相似文献
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Levent Şaylan Barış Çaldağ Fatih Bakanoğulları Hüseyin Toros Mustafa Yazgan Orhan Şen Yunus Özkoca 《洁净——土壤、空气、水》2011,39(5):491-501
Pollutants affect not only the environment in which they originate since they are also transported by air currents to other locations. For this reason, air pollution is a global problem for all countries and the air and water quality need to be monitored carefully. More information on precipitation chemistry is required to determine the source of pollution as well as its effects on the ecosystems. In this study, precipitation chemistry has been analyzed for the first time by using simple bulk collectors located at four different sites in Northwest Turkey for a period of two years. About 650 sequential rainwater samples were collected and analyzed for pH, electrical conductivity, anions such as , , Cl?, and cations such as Na+, K+, Mg2+, Ca2+, and . The selected sites were under the effect of different environmental factors. Our results showed that the highest and concentrations were measured in the Northwest of the research area. Additionally, it has been found that Ca2+ ions are abundant within all rainwater samples. 相似文献