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201.
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203.
Prosanta Kumar Khan Manoj Ghosh Partha Pratim Chakraborty Debdeep Mukherjee 《Pure and Applied Geophysics》2011,168(10):1693-1706
Seismicity data of northeast India, recorded between 1986 and 1999 by a local network, are analysed for estimation of b-values. Based on the obtained values, viz. low (b ≤ 0.5), moderate (0.5 < b ≤ 0.7) and high (b > 0.7), the study area is classified into different seismic-domains. An assessment of stress level is also carried out in
identifying seismic-domains. Seismic activities, though mostly confined in some sectors, are presumably triggered by mutual
interaction of the Shillong Plateau, Mikir Hills, Indo-Burman Ranges and the easternmost part of the Himalayas, and the contributions
from deep-seated fractures cannot be ignored. The results resemble the seismic character of a foreland setting adjacent to
a convergent margin. The b-values estimated for 240 square grids of dimension 0.6° × 0.6° over five seismic domains indicate wide variation. An analysis
of cumulative seismic moment release (M
O) in different layers also indicates an anomaly in reference to the total seismic-energy budget of the five zones. The lower
b-value and higher M
O recorded at relatively lower depth (~30 km) towards the southwest of the study area might be associated with upward bulging
of a strong lithosphere. The bulging is perhaps regionally compensated by the downward flexing of the descending Indian lithosphere
beneath the Upper Assam area; features unequivocally observed in any foreland setup. Towards the north and east of the study
area, random variations of in both b-value and M
O along the converging zone suggest a varied tectonic environment with active interaction between the tectonic elements in
these areas. 相似文献
204.
Dipankar Chakraborti Mohammad Mahmudur Rahman Bhaskar Das Bishwajit Nayak Arup Pal Mrinal Kumar Sengupta Md. Amir Hossain Sad Ahamed Manabendranath Sahu Kshitish Chandra Saha Subhash Chandra Mukherjee Shyamapada Pati Rathindra Nath Dutta Quazi Quamruzzaman 《Environmental Earth Sciences》2013,70(5):1993-2008
The authors’ survey of the Ganga–Meghna–Brahmaputra (GMB) plain (area 569,749 km2; population >500 million) over the past 20 years and analysis of more than 220,000 hand tube-well water samples revealed groundwater arsenic contamination in the floodplains of the Ganga–Brahmaputra river (Uttar Pradesh, Bihar, Jharkhand, West Bengal, and Assam) in India and the Padma–Meghna–Brahmaputra river in Bangladesh. On average, 50 % of the water samples contain arsenic above the World Health Organization guideline value of 10 μg/L in India and Bangladesh. More than 100 million people in the GMB plain are potentially at risk. The authors’ medical team screened around 155,000 people from the affected villages and registered 16,000 patients with different types of arsenical skin lesions. Arsenic neuropathy and adverse pregnancy outcomes have been recorded. Infants and children drinking arsenic-contaminated water are believed to be at high risk. About 45,000 biological samples analyzed from arsenic-affected villages of the GMB plain revealed an elevated level of arsenic present in patients as well as non-patients, indicating that many are sub-clinically affected. In West Bengal and Bangladesh, there are huge surface water in rivers, wetlands, and flooded river basins. In the arsenic-affected GMB plain, the crisis is not over water scarcity but about managing the available water resources. 相似文献
205.
Variogram Fractal Dimension Based Features for Hyperspectral Data Dimensionality Reduction 总被引:1,自引:0,他引:1
Kriti Mukherjee Jayanta K Ghosh Ramesh C. Mittal 《Journal of the Indian Society of Remote Sensing》2013,41(2):249-258
In this paper a new approach for fractal based dimensionality reduction of hyperspectral data has been proposed. The features have been generated by multiplying variogram fractal dimension value with spectral energy. Fractal dimension bears the information related to the shape or characteristic of the spectral response curves and the spectral energy bears the information related to class separation. It has been observed that, the features provide accuracy better than 90 % in distinguishing different land cover classes in an urban area, different vegetation types belonging to an agricultural area as well as various types of minerals belonging to the same parent class. Statistical comparison with some conventional dimensionality reduction methods validates the fact that the proposed method, having less computational burden than the conventional methods, is able to produce classification statistically equivalent to those of the conventional methods. 相似文献
206.
We present an analysis of Chandra ACIS observations of the field of TeV J2032+4130, the first unidentified TeV source, detected serendipitously by HEGRA. This
deep (48.7 ks) observation of the field follows up on an earlier 5 ks Chandra director’s discretionary observation. Of the numerous point-like X-ray sources in the field, the brightest are shown to be
a mixture of early and late-type stars. We find that several of the X-ray sources are transients, exhibiting rapid increases
in count rates by factors 3–10, and similar in nature to the one, hard absorbed transient source located in the earlier Chandra observation of the field. None of these transient sources are likely to correspond to the TeV source. Instead, we identify
a region of diffuse X-ray emission within the error circle of the TeV source and consider its plausible association. 相似文献
207.
208.
Anirban Akhand Anirban Mukhopadhyay Abhra Chanda Sandip Mukherjee Abhishek Das Sourav Das Sugata Hazra Debasis Mitra S. B. Choudhury K. H. Rao 《Journal of the Indian Society of Remote Sensing》2017,45(1):147-154
Sundarban, the largest single patch of mangrove forest of the world is shared by Bangladesh (~ 60 %) and India (~ 40 %). Loss of mangrove biomass and subsequent potential emission of carbon dioxide is reported from different parts of the world. We estimated the loss of above ground mangrove biomass and subsequent potential emission of carbon dioxide in the Indian part of the Sundarban during the last four decades. The loss of mangrove area has been estimated with the help of remotely sensed data and potential emission of carbon dioxide has been evaluated with the help of published above ground biomass data of Indian Sundarban. Total loss of mangrove area was found to be 107 km2 between the year 1975 and 2013. Amongst the total loss ~60 % was washed away in the water by erosion, ~ 23 % was converted into barren lands and the rest were anthropogenically transformed into other landforms. The potential carbon dioxide emission due to the degradation of above ground biomass was estimated to be 1567.98 ± 551.69 Gg during this period, which may account to 64.29 million $ in terms of the social cost of carbon. About three-forth of the total mangrove loss was found in the peripheral islands which are much more prone to erosion. Climate induced changes and anthropogenic land use change could be the major driving force behind this loss of ‘blue carbon’. 相似文献
209.
Sukalpa Karmakar Joydeep Mukherjee Somnath Mukherjee 《International Journal of Environmental Science and Technology》2018,15(4):801-810
Phytoremediation is a proven low-cost and sustainable method for the removal of toxic pollutants from water. This green technology has been practiced for the past several years all over the world. In the present study, the interaction of fluoride on the surface of the floating aquatic plant water lettuce (Pistia stratiotes) during fluoride removal was investigated. Batch kinetic studies were performed to examine the fluoride uptake capacity of the plant with different initial fluoride concentrations such as 3, 5, 10, and 20 mg/L. The effects of various process parameters on fluoride uptake dynamics such as pH, plant biomass, initial fluoride concentration, and time were examined. Freundlich’s isotherm model was found to (R 2 = 0.957) fit well to the experimental data. The nature of reaction order followed pseudo-first-order kinetics, when the initial fluoride level in the solution was 5 mg/L. The experimental findings showed that the removal mechanism was driven by biosorption phenomenon. High fluoride concentration in the solution reduced the growth ratio of P. stratiotes. The lowest growth ratio of this aquatic macrophyte was found to be 76.80 ± 3.73% at 20 mg/L fluoride concentration. At lower fluoride concentrations such as 3 and 5 mg/L, the growth ratio of the plant was not reduced significantly. 相似文献
210.
Joshi Aditya U. Sant Dhananjay A. Parvez Imtiyaz A. Rangarajan Govindan Limaye Manoj A. Mukherjee Soumyajit Charola Mitesh J. Bhatt Meghnath N. Mistry Sagar P. 《International Journal of Earth Sciences》2018,107(1):191-201
International Journal of Earth Sciences - We report, using the microtremor method, a subsurface granitic pluton underneath the Narukot Dome and in its western extension along a WNW profile, in... 相似文献