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121.
Ganesh Chandra Kisku Sandeep Yadav Rajnish Kumar Sharma Mahendra Pal Singh Negi 《Environmental Earth Sciences》2012,67(7):2109-2120
Coal, a fossil fuel, is the largest source of energy for the generation of electricity in India. In order to study the potential environmental hazards by coal based power plants, particulate matters were collected using Stack Monitoring Kit and gaseous pollutants by Automatic Flue Gas Analyzer. The morphological and chemical properties, mineralogical composition and particle size distributions have been determined by SEM–EDX, XRD and CILAS. The data revealed the presence of particulate matters, SO2, NOx in the range of 236–315, 162–238, 173–222 mg/Nm3 respectively. The emission of CO2 was in the range of 43,004–60,115 Nm3/h with an average of 52,830 Nm3/h. Among the elements, Fe > Mn > Al > Zn > B > Ni > Cr > Cu were present in substantially higher proportion than Pb > Mo > Cd > Se > As > Hg. It was found that most of the elements were concentrated on fly ash surface rather than coal, bottom ash and pond ash. This variation may be attributed to the fineness of fly ash particles with large surface ratio to mass. Mineralogical studies of coal and fly ash by X-ray diffraction revealed the presence of mullite, quartz, cristobalite and maghemite. Presence of mullite and quartz found in fly ash indicate the conversion of complex minerals to mullite and quartz at high temperature. Transfer Coefficient was calculated to determine the ratio of the enrichment of trace elements in fly or bottom ash with respect to coal and pond ash. 相似文献
122.
Sandeep Singh Munendra Singh A. K. Choudhary Anju Saxena I. B. Singh A. K. Jain 《International Journal of Earth Sciences》2010,99(8):1991-1997
The influx of Sr responsible for increase in marine Sr has been attributed to rise of Himalaya and weathering of the Himalayan
rocks. The rivers draining Himalaya to the ocean by the northern part of the Indian sub-continent comprising the Ganga Alluvial
Plain (GAP) along with Central parts of the Himalaya and the northern part of the Indian Craton are held responsible for the
transformation of Sr isotopic signature. The GAP is basically formed by the Himalayan-derived sediments and serves as transient
zone between the source (Himalaya) and the sink (Bay of Bengal). The Gomati River, an important alluvial tributary of the
Ganga River, draining nearly 30,500 km2 area of GAP is the only river which is originating from the GAP. The river recycles the Himalayan-derived sediments and transport
its weathering products into the Ganga River and finally to Bay of Bengal. 11 water samples were collected from the Gomati
River and its intrabasinal lakes for measurement of Sr isotopic composition. Sr concentration of Gomati River water is about
335 μg/l, which is about five times higher than the world’s average of river water (70 μg/l) and nearly three times higher
than the Ganga River water in the Himalaya (130 μg/l) The Sr isotopic ratios reported are also higher than global average
runoff (0.7119) and to modern seawater (0.7092) values. Strong geochemical sediment–water interaction appearing on surface
is responsible for the dissolved Sr isotopic ratios in the River water. Higher Sr isotopic rations found during post-monsoon
than in pre-monsoon season indicate the importance of fluxes due to monsoonal erosion of the GAP into the Gomati River. Monsoon
precipitation and its interaction with alluvium appear to be major vehicle for the addition of dissolved Sr load into the
alluvial plain rivers. This study establishes that elevated 87Sr/86Sr ratios of the Gomati River are due to input of chemical weathering of alluvial material present in the Ganga Alluvial Plain. 相似文献
123.
V. Sivakumar Binay Kumar Sandeep Kumar Srivastava B. Gopala Krishna Pradeep Kumar Srivastava A. S. Kiran Kumar 《Journal of the Indian Society of Remote Sensing》2012,40(4):551-564
Digital Elevation Model (DEM) is an important prerequisite for understanding the lunar surface. However, making accurate DEM is a very challenging task due to (a) lack of support of projection parameters in COTS packages (eg. PCI Geomatica), which are to be used in generation of Lunar DEM and (b) unavailability of Ground Control Points (GCPs). In the present study, DEM generation of lunar surface was attempted without GCPs using Rational Function (RF) model from Chandrayaan-1 TMC triplet images. In the study, a good correlation (of almost same order) is observed between Nadir-Fore (NF), Nadir - Aft (NA), Fore - Aft (FA) and Fore - Nadir - Aft (FNA) image pairs. The results suggest that DEM for lunar surface can be created without GCPs using RF model. 相似文献
124.
This paper presents an efficient algorithm, FDA2DMT (Free Decay Analysis for 2D Magnetotellurics (MT)), based on eigenmode
approach to solve the relevant partial differential equation, for forward computation of two-dimensional (2D) responses. The
main advantage of this approach lies in the fact that only a small subset of eigenvalues and corresponding eigenvectors are
required for satisfactory results. This small subset (pre-specified number) of eigenmodes are obtained using shift and invert
implementation of Implicitly Restarted Lanczos Method (IRLM). It has been established by experimentation that only 15–20%
smallest eigenvalue and corresponding eigenvectors are sufficient to secure the acceptable accuracy. Once the single frequency
response is computed using eigenmode approach, the responses for subsequent frequencies can be obtained in negligible time.
Experiment design results for validation of FDA2DMT are presented by considering two synthetic models from COMMEMI report,
Brewitt-Taylor and Weaver (1976) model and a field data based model from Garhwal Himalaya. 相似文献
125.
R T RATHEESH KUMAR TANMAY K MAJI SURESH CH KANDPAL D SENGUPTA RAJESH R NAIR 《Journal of Earth System Science》2011,120(3):447-458
Global estimates of the elastic thickness (Te) of the structure of passive continental margins show wide and varying results
owing to the use of different methodologies. Earlier estimates of the elastic thickness of the North Atlantic passive continental
margins that used flexural modelling yielded a Te value of ~20–100 km. Here, we compare these estimates with the Te value
obtained using orthonormalized Hermite multitaper recovered isostatic coherence functions. We discuss how Te is correlated
with heat flow distribution and depth of necking. The E–W segment in the southern study region comprising Nova Scotia and
the Southern Grand Banks show low Te values, while the zones comprising the NE–SW zones, viz., Western Greenland, Labrador,
Orphan Basin and the Northern Grand Bank show comparatively high Te values. As expected, Te broadly reflects the depth of
the 200–400°C isotherm below the weak surface sediment layer at the time of loading, and at the margins most of the loading
occurred during rifting. We infer that these low Te measurements indicate Te frozen into the lithosphere. This could be due
to the passive nature of the margin when the loads were emplaced during the continental break-up process at high temperature
gradients. 相似文献
126.
A set of large deformation experiments are presented to simulate folding pattern at various energy states during formation.
In order to numerically simulate this phenomenon, a rectangular layer of shale is generated and compressed at various strain
rates. The results reveal the variation in distribution of stress along the length of the bed. The stress distribution during
elastic behaviour of shale bed at low compression rate and the change in stress distribution leading to rupture at high compression
rates is discussed. Wavelength, limb length, bulk shortening, stress distribution, displacement of particles along the length
of the bed is considered for comparative study of the fold pattern generated at various compression rates. The nature and
position of crack generated during the formation of fold is also explained. After rupture in shale bed, the generation of
fault and stress distribution in limbs of fold sliding over one another is also described. 相似文献
127.
Bibhash Nath Jyoti Prakash Maity Jiin-Shuh Jean Gavin Birch Sandeep Kar Huai-Jen Yang Ming-Kuo Lee Rasmani Hazra Debashis Chatterjee 《Applied Geochemistry》2011,26(5):705-713
Major ion and trace element analyses were performed on groundwater samples collected from the Bengal Delta (Chakdaha municipality, West Bengal and Manikgonj town, Bangladesh) and Chianan Plains (SW Taiwan) to compare geochemical characteristics. Results showed that concentrations of Na, K, Mg, Cl and SO4 were generally higher in Chianan Plain (CNP) groundwaters, while high Ca was observed in Bengal Delta Plain (BDP) groundwater. Measured As concentrations in groundwaters of BDP and CNP showed large variations, with mean As concentrations of 221 μg/L (range: 1.1-476 μg/L) in Chakdaha, 60 μg/L (range: 0.30-202 μg/L) in Manikgonj, and 208 μg/L (range: 1.3-575 μg/L) in CNP groundwater. The Fe-reduction mechanism was found to be the dominant geochemical process in releasing As from sediment to groundwater in Chakdaha, West Bengal, however the Mn-reduction process was dominant in groundwaters of Manikgonj, Bangladesh. In Chianan Plain groundwater, a combination of geochemical processes (e.g., bacterial Fe-reduction, mineral precipitation and dissolution reactions) controlled release of As. Fluorescence spectral patterns of the groundwater showed low relative fluorescence intensity (RFI) of dissolved humic substances in BDP groundwater (mean: 63 and 72 QSU, Chakdaha and Manikgonj, respectively), while high RFI was observed in CNP groundwater (mean: 393 QSU). The FT-IR spectra of the extracted humic acid fractions from sediments of Chianan Plain showed a stronger aliphatic band at 2850-3000 cm−1 and a higher resolved fingerprint area (from 1700 to 900 cm−1) compared with BDP sediments. The geochemical differences between the study areas may play a crucial role in the clinical manifestation of Blackfoot disease observed only in Chianan Plain, SW Taiwan. 相似文献
128.
The influence of El Nio-Southern Oscillation (ENSO) on the convectively coupled Kelvin waves over the tropical Pacific is investigated by comparing the Kelvin wave activity in the eastern Pacific (EP) El Nio, central Pacific (CP) El Nio, and La Nia years, respectively, to 30-yr (1982-2011) mean statistics. The convectively coupled Kelvin waves in this study are represented by the two leading modes of empirical orthogonal function (EOF) of 2-25-day band-pass filtered daily outgoing longwave radiation (OLR), with the estimated zonal wavenumber of 3 or 4, period of 8 days, and eastward propagating speed of 17 ms-1 . The most significant impact of ENSO on the Kelvin wave activity is the intensification of the Kelvin waves during the EP El Nios. The impact of La Nia on the reduction of the Kelvin wave intensity is relatively weaker, reflecting the nonlinearity of tropical deep convection and the associated Kelvin waves in response to ENSO sea surface temperature (SST) anomalies. The impact of the CP El Nio on the Kelvin waves is less significant due to relatively weaker SST anomalies and smaller spatial coverage. ENSO may also alter the frequency, wavelength, and phase speed of the Kelvin waves. This study demonstrates that low-frequency ENSO SST anomalies modulate high-frequency tropical disturbances, an example of weather-climate linkage. 相似文献
129.
The study aims to simulate the peri-urban growth dynamics in a growing region of India using Weights of Evidence (WOE) based cellular automata model. The growth process was expressed as a function of four causative variables corresponding to which seven data layers were generated in a Geographic Information Systems environment. The model was calibrated for the period 2000–2005 using Kappa indices and fuzzy set theory based two way comparison method. The Kappa value was 0.7, while the value of Klocation and Khisto were 0.81 and 0.93, respectively. The fuzzy similarity values increased for small to large neighbourhood sizes which showed that the model was able to simulate the contiguous and dense growth. However, for dispersed and isolated growth the model showed less accuracy. The model was validated for period 2005–2010 and revealed a Kappa value of 0.88, while value of Klocation and Khisto were 0.91 and 0.96, respectively. 相似文献
130.
O. S. R. U. BHANU KUMAR 《水文科学杂志》2013,58(5):515-525
Abstract This paper presents the relationship between Indian summer monsoon total rainfall and two parameters from Eurasian snow cover, one being the winter snow cover extent and the other the area of spring snowmelt. Satellite-derived Eurasian snow cover extent and Indian monsoon rainfall data were obtained from the NOAA/NESDIS and the India Meteorological Department (IMD) for the period 1966–1985. Seasonal cyclic variations of snow cover showed a higher swing in both the winter and the spring seasons of the cycle as compared to the remaining seasons of the year in the lower region of the cycle. The established inverse relation between winter snow cover and monsoon rainfall during June to September is further extended. Winter snow cover is very strongly correlated with spring snowmelt over Eurasia. Spring snowmelt area is obtained by subtracting the May snow cover extent from that of the previous February. The variations of spring snowmelt were also compared with Indian total monsoon rainfall. The detected correlation is stronger between snowmelt and monsoon rainfall than between the winter snow cover and the monsoon rainfall. There is also a significant multiple correlation among winter snow cover, spring snowmelt and monsoon rainfall. Lastly, a significant multiple correlation suggested a multiple regression equation which might improve the climatic prediction of monsoon rainfall over India. 相似文献