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Amit Kumar Arvind Chandra Pandey Najmul Hoda A. T. Jeyaseelan 《Journal of the Indian Society of Remote Sensing》2011,39(2):213-224
The present study analyzes the built-up expansion of Ranchi urban agglomeration over a period of about 8 decades from 1927–2005.
Satellite images and topographical maps were used to evaluate land use dynamics during these periods. Built-up growth of 473.7%
during 1927–2005 was primarily at the expense of agricultural land along with reduction of natural water bodies reflects negative
impacts of built-up expansion, which increased many folds in recent decades. The built-up growth is also analyzed with reference
to population growth, land consumption rate and land transformation. The land loss due to increasing built-up growth of Ranchi
were compared with other capital regions and cities along with population increase to provide insight into the possible scenario
of built-up expansion in Ranchi urban area. 相似文献
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Fatemeh Hadavi Marziyeh Notghi Moghaddam Hoda Mousazadeh 《Arabian Journal of Geosciences》2010,3(2):133-139
The aim of this study is to determine calcareous nannofossil species found in Kamar-Kuh area and demonstrate this use for biostratigraphic studies. The Qom Formation is widely distributed in Kamar-Kuh section and has nine members(a–f). In this study, 12 samples were taken and prepared with smear slide. Some of the determined species are listed below, and some of them are photographed by light and scanning microscope. According to obtained nannofossils, 16 species, nine genera, and six families were determined. Obtained nannofossils indicated age of Burdigalian–Serravalian (middle Miocene) for this section. 相似文献
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Christophe Nkem Kamel Hammami Idriss Yacoub Halalaw Luc Calvin Owono Owono Nejm-Eddine Jaidane 《Astrophysics and Space Science》2014,349(1):171-179
We report on ab initio coupled-cluster calculations of the interaction potential energy surface for the HCNH+–He complex. The aug-cc-pVTZ Gaussian basis, to which is added a set of bond functions placed at mid-distance between HCNH+ center of mass and He atom is used. The HCNH+ bonds length are set to their values at the equilibrium geometry, i.e., r e [HC]=1.0780 Å, r e [CN]=1.1339 Å and r e [NH]=1.0126 Å. The interaction energy presents a global minimum located $266.9~\mathrm{cm^{-1}}$ below the HCNH+–He dissociation limit. Using the interaction potential obtained, we have computed rotational excitation cross sections in the close-coupling approach and downward rate coefficients at low temperature (T≤120 K). It is expected that the data worked out in this study may be beneficial for further astrophysical investigations as well as laboratory experiments. 相似文献
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Marwan Ghanem Waseem Ahmad Yacoub Keilan Farah Sawaftah 《Environmental Earth Sciences》2017,76(9):347
A groundwater vulnerability assessment was carried out in order to understand and control the pollution sources affecting vulnerable regions in two adjacent catchments (Sarida and Natuf), located in the western middle part of the West Bank. The catchments were subjected to groundwater vulnerability mapping and assessment using the modified German State Geological Surveys (GLA method) method called Protective Cover and Infiltration Conditions method (PI method) via ArcGis 2014.2 software package in February of 2016. The results showed that the study area has high effectiveness of protective cover (P-factor), which was obtained by overlying top soil, bedrock, subsoil, and recharge layers. On the other hand, the dominant flow types, land usage, slopes, and topographical classification layers were overlaid to get the infiltration conditions (I-factor). The interaction between the two main factors was carried out in order to obtain the final spatially distributed π-factor values (vulnerability map), which was classified into four vulnerability classes. Statistically, about 4% of the overall area was of extreme vulnerability and concentrated along the sinking streams, while 22% was of low vulnerability and existed outside the main watersheds, followed by high vulnerability with 26%. The largest proportion with 48% of the overall area was of moderate vulnerability to groundwater contamination. 相似文献
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Wayne Arter† 《地球物理与天体物理流体动力学》2013,107(4):259-292
Abstract Nonlinear two-dimensional magnetoconvection, with a Boussinesq fluid driven across the field-lines, is taken as a model for giant-cell convection in the sun and late-type stars. A series of numerical experiments shows the sensitivity of the horizontal scale of convection to the applied field and to the Rayleigh number R. Overstable oscillations occur in cells as broad as they are deep, but increasing R leads to steady motions of much greater wavelength. Purely geometrical effects can cause oscillation: this work implies that strong horizontal field will in general lead to time-dependent convection. 相似文献
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Geological structure of the active foreland fold and thrust belt of Papua New Guinea has been interpreted using high-quality seismic-reflection data. Three en échelon anticlines, the Strickland, Cecilia and Wai Asi, are located along the frontal margin of the Papuan Fold Belt. All three are foreland-vergent and cut by hinterland-dipping thrust faults that sole into a common detachment beneath the Oligocene to Miocene Darai Limestone. Two of the anticlines are linked by a right-lateral transfer zone. Folding occurs primarily in the upper 2000 m of strata, which consist of Darai Limestone overlain by Miocene to Quaternary siliciclastic sedimentary rocks. Beneath the Darai Limestone lies the less-competent shaly Ieru Formation, which exhibits disharmonic folding and variable bed thickness. Seismic-reflection data clearly show that the Plio-Pleistocene upper Era Beds are deformed to the same extent as the underlying Darai Limestone, demonstrating that most of the observed deformation has occurred during the Late Pliocene and Pleistocene. 相似文献
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A key non-linear mechanism in a strong-field geodynamo is that a finite amplitude magnetic field drives a flow through the Lorentz force in the momentum equation and this flow feeds back on the field-generation process in the magnetic induction equation, equilibrating the field. We make use of a simpler non-linear?α?2-dynamo to investigate this mechanism in a rapidly rotating fluid spherical shell. Neglecting inertia, we use a pseudo-spectral time-stepping procedure to solve the induction equation and the momentum equation with no-slip velocity boundary conditions for a finitely conducting inner core and an insulating mantle. We present calculations for Ekman numbers (E) in the range 2.5× 10?3 to 5.0× 10?5, for?α?=α 0cos?θ?sin?π?(r?ri ) (which vanishes on both inner and outer boundaries). Solutions are steady except at lower E and higher values of?α?0. Then they are periodic with a reversing field and a characteristic rapid increase then equally rapid decrease in magnetic energy. We have investigated the mechanism for this and shown the influence of Taylor's constraint. We comment on the application of our findings to numerical hydrodynamic dynamos. 相似文献
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THANASIS HADZILACOS NECTARIA TRYFONA† 《International journal of geographical information science》2013,27(2):179-203
Abstract. A formal, yet practical, GeoRelational Data Model (GRDM) is presented for the logical database design phase of the development of spatial information systems. Geographic applications are viewed in the context of information systems development. The generic needs of modelling spatial data are analyzed; it is concluded that they are not served satisfactorily by existing data models, so specifications of modelling tools for spatial application design are given. GRDM provides a set of representational constructs (relations and layers for the logical schema; virtual layers, object classes and spatial constraints for the user views) on top of well-established models. It constitutes part of a full, easily automated application design methodology. Extensive examples demonstrate the relevance, and ease-of-use of the platform-independent GRDM. 相似文献