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Hasan Hüseyin Aksu Mehmet Zakir Kanbur Muhittin Görmüş 《Arabian Journal of Geosciences》2017,10(17):387
A ground penetrating radar (GPR) survey was performed on the E?irdir Lake to obtain the structural properties of Kumdanl? and surrounding faults. GPR data was collected along ten profiles in various directions by using 100–200-MHz GPR antennas. The radar sections showed that the Kumdanl? Fault, SW-NE in direction, and also some other neighboring NW-SE normal faults have played an active role in forming the E?irdir-Hoyran Lakes. The deformation and the geometry obtained from the results show that the Kumdanl? Fault is a sinistral strike-slip fault including oblique and segmented displacements. The other faults (Kemerdam? and Akkeçili) have mainly normal fault systems. Their trends are generally NW-SE in direction. It is also observed that they are younger than the Kumdanl? Fault system. These fault properties demonstrate the E?irdir Lake side has an extensional structure trending SW-NE. 相似文献
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Incorporating carbon offsets in the design of cap-and-trade programs remains a controversial issue because of its potential unintended impacts on emissions. At the heart of this discussion is the issue of crediting of emissions reductions. Projects can be correctly, over- or under-credited for their actual emissions reductions. We develop a unified framework that considers the supply of offsets within a cap-and-trade program that allows us to compare the relative impact of over-credited offsets and under-credited emissions reductions on overall emissions under different levels of baseline stringency and carbon prices. In the context of a national carbon pricing scheme that includes offsets, we find that the emissions impacts of over-credited offsets can be fully balanced out by under-credited emissions reductions without sacrificing a significant portion of the overall supply of offsets, provided emissions baselines are stringent enough. In the presence of high predicted business-as-usual (BAU) emissions uncertainty or low carbon prices, to maintain the environmental integrity of the program, baselines need to be set at stringent levels, in some cases below 50 percent of predicted BAU emissions. As predicted BAU emissions uncertainty declines or as the carbon market achieves higher equilibrium prices, however, less stringent baselines can balance out the emissions impacts of over-credited offsets and under-credited emissions reductions. These results imply that to maintain environmental integrity of offsets programs, baseline stringency should be tailored to project characteristics and market conditions that influence the proportion of over-credited offsets to under-credited emissions reductions. 相似文献
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In order to make an in-depth comparison between theory and observations, we analyse the light and velocity curves of various hydrodynamical models simulating RRab stars. The observations are represented by empirical formulae, derived in this and our earlier papers. It is shown that the overwhelming majority of the models tested do not follow the empirical relations regarding the shape of the light curves and the physical parameters. In almost all cases the luminosities predicted from the model light curves are significantly lower than the corresponding model values. The overall discrepancy of the models is an important indication of the limitation of the applicability of the present theoretical light and velocity curves in the determination of the physical parameters of these stars. In transforming the theoretical data to the observed light curves in V colour and in computing the observed radial velocities, it is shown that both bolometric correction and tracing the line-forming regions have considerable effects on the evaluation of the observed quantities. In an effort to resolve the discrepancy between theory and observations, it is suggested that a proper evaluation of the bolometric correction and radial velocity based on complete dynamical atmosphere models may be a useful step in this direction. 相似文献
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Shashi M. Kanbur Chow-Choong Ngeow 《Monthly notices of the Royal Astronomical Society》2006,369(2):705-722
Period–colour (PC) and amplitude–colour (AC) relations are studied for the Large Magellanic Cloud (LMC) Cepheids under the theoretical framework of the hydrogen ionization front (HIF)–photosphere interaction. LMC models are constructed with pulsation codes that include turbulent convection, and the properties of these models are studied at maximum, mean and minimum light. As with Galactic models, at maximum light the photosphere is located next to the HIF for the LMC models. However, very different behaviour is found at minimum light. The long-period ( P > 10 d) LMC models imply that the photosphere is disengaged from the HIF at minimum light, similar to the Galactic models, but there are some indications that the photosphere is located near the HIF for the short-period ( P < 10 d) LMC models. We also use the updated LMC data to derive empirical PC and AC relations at these phases. Our numerical models are broadly consistent with our theory and the observed data, though we discuss some caveats in the paper. We apply the idea of the HIF–photosphere interaction to explain recent suggestions that the LMC period–luminosity (PL) and PC relations are non-linear with a break at a period close to 10 d. Our empirical LMC PC and PL relations are also found to be non-linear with the F -test. Our explanation relies on the properties of the Saha ionization equation, the HIF–photosphere interaction and the way this interaction changes with the phase of pulsation and metallicity to produce the observed changes in the LMC PC and PL relations. 相似文献
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S.M. Kanbur D. Iono N.R. Tanvir M.A. Hendry 《Monthly notices of the Royal Astronomical Society》2002,329(1):126-134
We show how Principal Component Analysis can be used to analyse the structure of Cepheid light curves. This method is more efficient than Fourier analysis at bringing out changes in light curve shape as a function of period. Using this technique, we study the shape of fundamental and first-overtone mode Cepheid light curves in the Galaxy, LMC and SMC over a wide period range. For fundamentals, we find evidence for structural changes at It is suggested that the feature at is associated with a resonance in the Cepheid normal-mode spectrum. For overtones, we recover the Z shape in the R 21 period plane and reproduce the metallicity dependence of this Z shape. 相似文献
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Shashi M. Kanbur Chow-Choong Ngeow Greg Feiden 《Monthly notices of the Royal Astronomical Society》2007,380(2):819-827
Period–colour (PC) and amplitude–colour (AC) relations at maximum, mean and minimum light are constructed from a large grid of full amplitude hydrodynamic models of Cepheids with a composition appropriate for the Small Magellanic Cloud (SMC). We compare these theoretical relations with those from observations. The theoretical relations are, in general, in good agreement with their observational counterparts, though there exist some discrepancy for short period (log [ P ] < 1) Cepheids. We outline a physical mechanism which can, in principle, be one factor to explain the observed PC/AC relations for the long and short period Cepheids in the Galaxy, Large Magellanic Cloud (LMC) and SMC. Our explanation relies on the hydrogen ionization front (HIF)–photosphere interaction and the way this interaction changes with pulsation period, pulsation phase and metallicity. Since the PC relation is connected with the period–luminosity (PL) relation, it is postulated that such a mechanism can also explain the observed properties of the PL relation in these three galaxies. 相似文献
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Chow-Choong Ngeow Shashi M. Kanbur Earl P. Bellinger Marcella Marconi Ilaria Musella Michele Cignoni Ya-Hong Lin 《Astrophysics and Space Science》2012,341(1):105-113
This paper discusses two aspects of current research on the Cepheid period-luminosity (P-L) relation: the derivation of mid-infrared (MIR) P-L relations and the investigation of multi-phase P-L relations. 相似文献