The effect of a poloidal magnetic field on the structure of isothermal gas spheres in hydrostatic equilibrium under the pressure of partially degenerate relativistic electrons and radiation has been considered. An equation of state involving Fermi-Dirac functionsF2() andF3() has been used. Modifications to the values of various structural parameters have been tabulated for the cases c=0, 2, 3, 5, and 10, c being the central degeneracy parameter. 相似文献
This study has been undertaken to examine the occurrence of climate change in Tamil Nadu, the southernmost state of India and its impact on rainfall pattern which is a primary constraint for agricultural production. Among the five sample stations examined across the state, the minimum temperature has increased significantly in Coimbatore while the same has decreased significantly in Vellore whereas both minimum and maximum temperatures have increased significantly in Madurai since 1969 with climate change occurring between late 1980s and early 1990s. As a result, the south-west monsoon has been disturbed with August rainfall increasing with more dispersion while September rainfall decreasing with less dispersion. Thus, September, the peak rainfall month of south-west monsoon before climate change, has become the monsoon receding month after climate change. Though there has been no change in the trend of the north-east monsoon, the quantity of October and November rainfall has considerably increased with increased dispersion after climate change. On the whole, south-west monsoon has decreased with decreased dispersion while north-east monsoon has increased with increased dispersion. Consequently, the season window for south-west monsoon crops has shortened while the north-east monsoon crops are left to fend against flood risk during their initial stages. Further, the incoherence in warming, climate change and rainfall impact seen across the state necessitates devising different indigenous and institutional adaptation strategies for different regions to overcome the adverse impacts of climate change on agriculture.
An earthquake hazard zonation map of Sikkim Himalaya is prepared using eight thematic layers namely Geology (GE), Soil Site
Class (SO), Slope (SL), Landslide (LS), Rock Outcrop (RO), Frequency–Wavenumber (F–K) simulated Peak Ground Acceleration (PGA),
Predominant Frequency (PF), and Site Response (SR) at predominant frequencies using Geographic Information System (GIS). This
necessitates a large scale seismicity analysis for seismic source zone classification and estimation of maximum earthquake
magnitude or maximum credible earthquake to be used as a scenario earthquake for a deterministic or quasi-probabilistic seismic
scenario generation. The International Seismological Center (ISC) and Global Centroid Moment Tensor (GCMT) catalogues have
been used in the present analysis. Combining b-value, fractal correlation dimension (Dc) of the epicenters and the underlying tectonic framework, four seismic source zones
are classified in the northeast Indian region. Maximum Earthquake of MW 8.3 is estimated for the Eastern Himalayan Zone (EHZ) and is used to generate the seismic scenario of the region. The Geohazard
map is obtained through the integration of the geological and geomorphological themes namely GE, SO, SL, LS, and RO following
a pair-wise comparison in an Analytical Hierarchy Process (AHP). Detail analysis of SR at all the recording stations by receiver
function technique is performed using 80 significant events recorded by the Sikkim Strong Motion Array (SSMA). The ground
motion synthesis is performed using F–K integration and the corresponding PGA has been estimated using random vibration theory
(RVT). Testing for earthquakes of magnitude greater than MW 5, a few cases presented here, establishes the efficacy and robustness of the F–K simulation algorithm. The geohazard coverage
is overlaid and sequentially integrated with PGA, PF, and SR vector layers, in order to evolve the ultimate earthquake hazard
microzonation coverage of the territory. Earthquake Hazard Index (EHI) quantitatively classifies the terrain into six hazard
levels, while five classes could be identified following the Bureau of Indian Standards (BIS) PGA nomenclature for the seismic
zonation of India. EHI is found to vary between 0.15 to 0.83 quantitatively classifying the terrain into six hazard levels
as “Low” corresponding to BIS Zone II, “Moderate” corresponding to BIS Zone III, “Moderately High” belonging to BIS Zone IV,
“High” corresponding to BIS Zone V(A), “Very High” and “Severe” with new BIS zones to Zone V(B) and V(C) respectively. 相似文献
Ambient concentrations of organic carbon (OC), elemental carbon (EC) and water soluble inorganic ionic components (WSIC) of PM10 were studied at Giridih, Jharkhand, a sub-urban site near the Indo Gangatic Plain (IGP) of India during two consecutive winter seasons (November 2011–February 2012 and November 2012–February 2013). The abundance of carbonaceous and water soluble inorganic species of PM10 was recorded at the study site of Giridih. During winter 2011–12, the average concentrations of PM10, OC, EC and WSIC were 180.2?±?46.4; 37.2?±?6.2; 15.2?±?5.4 and 18.0?±?5.1 μg m?3, respectively. Similar concentrations of PM10, OC, EC and WSIC were also recorded during winter 2012–13. In the present case, a positive linear trend is observed between OC and EC at sampling site of Giridih indicates the coal burning, as well as dispersed coal powder and vehicular emissions may be the source of carbonaceous aerosols. The principal components analysis (PCA) also identifies the contribution of coal burning? +?soil dust, vehicular emissions?+?biomass burning and seconday aerosol to PM10 mass concentration at the study site. Backward trajectoy and potential source contributing function (PSCF) analysis indicated that the aerosols being transported to Giridih from upwind IGP (Punjab, Haryana, Uttar Pradesh and Bihar) and surrounding region. 相似文献
High-resolution EIGEN6C4 and EGM2008 Bouguer gravity data of 2190 degree spherical harmonic over the Singhbhum-Orissa Craton, India, have been generated from the International Centre for Global Earth Models. The Bouguer gravity anomaly difference maps of (i) in situ and EIGEN6C4, (ii) in situ and EGM2008 and iii) EIGEN6C4 and EGM2008 of the study area are compared. It reveals that EIGEN6C4 has lesser systematic error than EGM2008. However, from different profile plots of Bouguer gravity, east–west horizontal derivative and north–south horizontal derivative anomalies of the in situ, EIGEN6C4 and EGM2008, it is observed that most of the signatures of lithounits and geological structural elements are delineated very well by EGM2008 and match 94–98% with those of EIGEN6C4. Further, the Bouguer gravity, east–west horizontal derivative and north–south horizontal derivative anomalies of EGM2008 data over the study area have been used effectively for identifying various lithounits and geological structural elements. 相似文献
Pyritized bivalve mollusks have been revealed for the first time in upper Norian sedimentary rocks at the large orogenic Sentachan gold–antimony deposit in eastern Yakutia. It has been established that they are related to species of the genus Monotis (M. ex gr. jacutica (Teller) (specimen no. 2077/1, CSGM) and M. pachypleura (Teller) (specimen no. 2077/2, CSGM), which existed during the Monotis densistriata phase of the Norian Age of the Triassic Epoch presumably 211.5–214 Ma ago. The occurrence of two pyrite generations differing in morphology, sulfur impurity, and isotopic compositions corroborates the suggestion that pyritization of fauna was a discrete process. It has been shown that sulfur that formed owing to bacterial sulfate reduction and interaction with organic matter was involved in the pyritization of bivalve mollusks, whereas mixing of magmatic sulfur and sulfur derived from host sedimentary rocks participated in deposition of Au–Sb ore. 相似文献