Geoelectric and geochemical studies for hydrological characterization of canning and adjoining areas of South 24 Parganas district,West Bengal     

R. K. Majumdar  S. Kar  D. Talukdar  T. Duttagupta 《Journal of the Geological Society of India》2014,83(1):21-30

Integrated geoelectric and geochemical investigation were carried out in the Canning and adjoining areas to assess the prevailing groundwater conditions and chemical quality of groundwater. Geologically, the area is constituted of alluvial sediments of Quaternary age. Vertical electrical soundings (VES) in the area of investigation mostly show six layers consisting of top soil, saline water, clay layer, brackish water, clay layer and fresh-water bearing zone of appreciable thicknesses at depths of 137 to 182 meter at six locations and from 370 to 430 meter for other two locations under confined conditions. The result of VES studies significantly correspond with the borehole litholog and well log data. A litho-resistivity relationship is established for this area of investigation A Fence diagram is constructed to show the spatial variation of the sub-surface lithology and hydrological characteristics. Chemically the ground water is fresh and mixed cation and anion type as revealed from Piper-Trilinear diagram with TDS ranging from 699 to 1547 mg/l. The geochemical parameters like Total hardness (TH), Sodium absorption ratio (SAR), Soluble sodium percentage (SSP), Percentage of sodium (PS), Kelley’s ratio (KR), Residual sodium carbonate (RSC), Corrosivity ratio (CR), Gibbs ratios (GR), Chloro alkaline indices (CAI), Sea water contamination (SWC) are also calculated for examining the quality of groundwater in the area. The depth of occurrences of freshwater bearing ground water zones for drinking and irrigation purposes are occurring at depths from 137 meter to 430 meter in this area.  相似文献   

Metal Impregnated Silica‐Carbon Materials from Rice Husk: A Versatile Sorbent for Toxic Organics and Inorganics in Water and Air     

Sanhita Majumdar  Pijush Kanti Mandal  Sudip Kumar Das  Rabindranath Majumdar 《洁净——土壤、空气、水》2013,41(3):291-297

Carbon bearing materials derived from rice husk (RH) have long been recognized as sorbents for diverse chemicals – both organic and inorganic. This work presents an overview of studies demonstrating a single step process of carbonization of chemically pretreated RH to produce metal impregnated silica‐carbon char designated as silicarbon materials that can be utilized in sorbing out water‐borne organic and inorganic hazardous substances (such as phenol, hexavalent chromium, fluoride, and arsenic) and air‐borne volatile organic chemicals (such as acetone, chloroform, benzene, and pyridine). The metal‐impregnated silicarbon solids derived from RH appear to constitute renewable, low‐cost, user‐friendly, and efficient materials for control systems for indoor air contamination and for industrial as well as non‐industrial hazardous aqueous pollution.  相似文献   

Water problems of Bengaluru — the fastest growing city of India     

Amar Kumar Majumdar 《Journal of the Geological Society of India》2012,79(4):424-424

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Evolution of primordial black holes in Jordan–Brans–Dicke cosmology     

A. S. Majumdar  D. Gangopadhyay  L. P. Singh 《Monthly notices of the Royal Astronomical Society》2008,385(3):1467-1470

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Delineation of structural features over a part of the Bay of Bengal using total and balanced horizontal derivative techniques     

Satya Narayan  Soumyashree Debasis Sahoo  Ujjawal Kumar  Vipin Kumar Pathak  T. J. Majumdar 《国际地球制图》2017,32(4):351-366

The present study deals with classical problem of edge detection in potential field data over complex tectonic regime for both shallower and deeper sources, simultaneously. Balanced horizontal derivative (BHD) technique is a latest edge detection concept which delineates edges using balancing of amplitude responses for both shallower and deeper sources. The BHD technique has been validated by comparing with total horizontal derivative (THD) technique. Initially, three different synthetic models have been generated with spherical, cylindrical and vertical prismatic objects at different depths and corresponding gravity responses have been enhanced using BHD and THD techniques. Structural features have been delineated from EIGEN6C4 free-air gravity data using THD and BHD techniques over a part of the Bay of Bengal. Major lineaments have been identified in N–S direction followed by those identified along the NE–SW, NW–SE and E–W directions. Both studies of synthetic models and real gravity data reveal that BHD is an advanced technique than THD.  相似文献   

Biogenic hydrogen sulphide emissions and non-sea sulfate aerosols over the Indian Sundarban mangrove forest     

D. Ganguly  R. Ray  N. Majumdar  C. Chowdhury  T. K. Jana 《Journal of Atmospheric Chemistry》2018,75(3):319-333

Temporal variations in atmospheric hydrogen sulphide concentrations and its biosphere-atmosphere exchanges were studied in the World’s largest mangrove ecosystem, Sundarbans, India. The results were used to understand the possible contribution of H₂S fluxes in the formation of atmospheric aerosol of different size classes (e.g. accumulation, nucleation and coarse mode). The mixing ratio of hydrogen sulphide (H₂S) over the Sundarban mangrove atmosphere was found maximum during the post-monsoon season (October to January) with a mean value of 0.59?±?0.02 ppb and the minimum during pre-monsoon (February to May) with a mean value of 0.26?±?0.01 ppb. This forest acted as a perennial source of H₂S and the sediment-air emission flux ranged between 1213?±?276 μg S m^?2 d^?1(December) and 457?±?114 μg S m^?2 d^?1 (August) with an annual mean of 768?±?240 μg S m^?2d^?1. The total annual emissions of H₂S from the Indian Sundarban were estimated to be 1.2?±?0.6 Tg S. The accumulation mode of aerosols was found to be more enriched with non-sea salt sulfate with an average loading of 5.74 μg m^?3 followed by the coarse mode (5.18 μg m^?3) and nucleation mode (1.18 μg m^?3). However, the relative contribution of Non-sea salt sulfate aerosol to total sulfate aerosol was highest in the nucleation mode (83%) followed by the accumulation (73%) and coarse mode (58%). Significant positive relations between H₂S flux and different modes of NSS indicated the likely link between H₂S, a dominant precursor for the non-sea salt sulfate, and non-sea sulfate aerosol particles. An increase in H₂S emissions from the mangrove could result in an increase in enhanced NSS in aerosol and associated cloud albedo, and a decrease in the amount of incoming solar radiation reaching the Sundarban mangrove forest.  相似文献   

Utilization of high-resolution EGM2008 gravity data for geological exploration over the Singhbhum-Orissa Craton,India     

S.K. Pal  T.J. Majumdar  Vipin Kumar Pathak  Satya Narayan  Ujjawal Kumar  Om Prakash Goswami 《国际地球制图》2016,31(7):783-802

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   

Distinct ruby suite at Sardapur, Orissa: A spectroscopic investigation     

Alik Sundar Majumdar  George Mathew 《Journal of the Geological Society of India》2012,80(5):715-722

Orissa is an important area for gem variety of corundum deposits in India. Spectroscopic studies, such as ESR, OAS on samples from Sardapur, Orissa, were carried out to ascertain the colour cause of corundum. Electron spin resonance (ESR) spectroscopic study was carried out on the samples to detect the presence of paramagnetic ions i.e. Fe²⁺, Fe³⁺, Ti⁴⁺, Cr³⁺ and V³⁺ etc. The variable temperature experiment carried out to observe the effect of heating on peak valence state change in paramagnetic ions. Samples were cut and polished to obtain the optical absorption spectrum (OAS) to detect the colour causing transition ions/defect centres. The samples of gem variety were step heated up to 300°C for colour enhancement studies. EPMA analysis has revealed the low chromium concentration in the rubies. The varying hues of red in the corundum are due to the presence of bivalent and trivalent iron and charge transfer process along with Cr³⁺ absorption in the 550 nm region.  相似文献   

Landuse classification for a part of kamiichi area,Japan, using visible,IR and thermal IR data     

T.J. Majumdar  B.B. Bhattacharya  S. Tanaka  A. Rikimaru 《国际地球制图》2013,28(2):39-44

Bendix 11 channel aerial MSS data have been used to generate landuse thematic classification using Image‐100 interactive image processing system for a part of Kamiichi area, Japan. Two different classification schemes were attempted, once with Visible and IR data using supervised classification technique and then with Thermal IR data using density slicing technique. Comparison of both the results shows that main features of interest are uniquely classified in both the cases. In addition, higher order classification could also be achieved using Visible, IR and Thermal IR data for each class of interest.  相似文献   

Geomorphological feature — A narrow rock bridge,Umthongkut area,West Khasi Hills district,Meghalaya     

S. K. Srivastava  P. K. Kothari  Sandeep Hamilton  Amit Majumdar 《Journal of the Geological Society of India》2009,74(2):284-284

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