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21.
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
22.
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
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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
26.
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
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The marble band of supposedly Raialo (Precambrian) age around Rajnagar in the Udaipur district of Rajasthan represents a large isoclinal fold with the two limbs coalesced and with the terminations marking the sharp hinges. The arcuate map pattern is due to coaxial refolding of the axial surface of the isoclinal fold, on which open, NNE-trending upright folds have been overprinted. The isoclinal folds of small scale are reclined or inclined in style and plunge gently westward where not involved in the upright folding. The axes of the isoclinal folds have been scattered by superposed folding, so that some of the isoclinal folds now plunge even to the south. The plunge of the upright folds is gentler and steeper in the limb zones of reclined and inclined isoclinal folds respectively. Subvertical upright folds occur only in the hinges of the westerly trending reclined folds. Interference patterns of dome-and-basin type and mirror-image type have formed in zones where both hinges and limbs of the early folds have been affected by upright folding. The structure of the marble band, the stratigraphic relations that the marble bears with the supposedly older Aravalli mica schists and migmatites of the Banded Gneissic Complex engulfing it, and the stratigraphic findings in adjacent terrains indicate that the Banded Gneissic Complex represents migmatized portions of the metasediments of the Aravalli and the Raialo groups, and is not the basement rock in central Rajasthan. Evidence for granitic rocks of at least two generations in the Early Precambrians of central Rajasthan is adduced.
Zusammenfassung Das Marmorband von vermutlichem Raialo-Alter (Präkambrium) in der Gegend um Rajnagar, Udaipur-Distrikt, Rajasthan, bildet eine große isoklinale Falte, deren beide Flanken sich zu einem scharfen Scharnier vereinigten. Das bogenförmige Muster auf der Karte entstand durch koaxiale Wiederfaltung der Axialfläche der isoklinalen Falte; auf dieser sind offene NNE-streichende senkrechte Falten überlagert. Die kleineren isoklinalen Falten liegen oder sind geneigt und tauchen flach nach W, soweit sie nicht in die senkrechte Faltung eingeschlossen sind. Die Achsen der isoklinalen Falten sind gestört durch überlagerte Faltung, so daß einige der isoklinalen Falten jetzt sogar nach Süden eintauchen. Das Eintauchen der senkrechten Falten ist flach an den Flanken der liegenden Falten und steil an den Flanken der geneigten Falten. Senkrecht abtauchende Falten treten nur in den Scharnieren der nach Westen streichenden, liegenden Falten auf. Überlagerungsmuster vom Dom-und-Becken-Typ und Spiegelbild-Typ bildeten sich in Zonen, wo die Scharniere und die Flanken der früheren Falten durch senkrechte Faltung beeinflußt worden sind. Die Struktur des Marmorbandes wie auch die stratigraphischen Wechselbeziehungen zwischen dem Marmor und dem vermutlich älteren Aravalli-Glimmerschiefer sowie den Migmatiten des gebänderten Gneiskomplexes weisen zusammen mit stratigraphischen Funden aus angrenzenden Gebieten darauf hin, daß die Gneise die migmatisierten Teile der Metasedimente der Aravalli- und der Raialogruppe darstellen und daß sie nicht das älteste Grundgebirge (Basement) von Zentral-Rajasthan sind. Hinweise für das Auftreten von Granitgesteinen von mindestens zwei Generationen des Frühpräkambriums von Zentral-Rajasthan werden angeführt.
Résumé La couche de marbre du précambrien présumé de la région de Rajnagar, district d'Udaipur, Rajasthan, forme un grand pli isoclinal dont les deux flancs fusionnent en une charnière aiguë. Le dessin en arc de la carte résulte d'un replissement coaxial de la surface axiale du pli isoclinal. Là, se superposent des plis ouverts, perpendiculaires, de direction NNE. Les plus petits plis isoclinaux sont couchés ou sont inclinés en nappes plongeantes vers l'Ouest jusqu'à ce que le pli vertical les englobe.Les axes des plis isoclinaux sont interrompus par un second plissement plus récent de sorte que quelques uns d'entre eux plongent. même aujourd'hui, vers le sud.L'inclinaison des plis verticaux est douce du côté des plis couchés et à pic du côté des plis inclinés. Des plis verticaux plongeants ne se présentent que dans les charnières des plis couchés et dirigés vers l'Ouest. La superposition des dessins de dôme et bassin-type avec le reflet-type se produisit dans les zônes où les charnières et les flancs des plis primitifs subirent l'influence des plis verticaux.La structure de la couche de marbre, les rapports des variations stratigraphiques entre le marbre et le mica-schiste, présumé plus âgé d'Aravalli, ainsi que le matériel métatectique du complexe rubané de gneiss indiquent en accord avec les fossiles de régions limitrophes, que les gneiss représentent les parties migmatisées des métasédiments des groupes Aravalli et Raialo et qu'ils ne forment pas le plus ancien socle du Rajasthan Central.
, , Raialo ( ) Rajnagar, Udaipur, Rajasthan, , . , , NNE. , , , . ; . , . . , , . , Aravalli, , , blli Raialo; Rajasthan. , - , Kajasthan'e.相似文献
30.
J. K. Biswas B. Bera R. Chanda S. K. Sarkar J. Majumdar S. Majumder S. Hazra 《International Journal of Environmental Science and Technology》2018,15(9):1867-1878
Lakes are functionally integral and biologically complex freshwater ecosystems which provide a vast array of ecosystem goods and services to society. Nowadays aquatic ecosystems are being used, misused and abused by diverse anthropogenic activities at an unprecedented rate. The management of lake water quality is usually directed to resolution of conflicts between maintenance of desirable water quality and human-induced degradation of aquatic environment. Nutrients play a decisive role in determining lake’s environmental state through regulation of its primary production. The present study on Saheb Bundh Lake located in Purulia District, West Bengal, India, was undertaken to assess the status of nutrients (nitrogen and phosphorus) subject to certain anthropogenic activities, and to construct models using best subset method which could be adopted as a nutrient management tool. The water samples were monitored for different physicochemical parameters adopting standard methods. It was found that the set of variables including turbidity, temperature, pH, redox potential and total hardness has been championed as the best subset of water quality explaining the dynamics of total phosphorus concentration of freshwater Saheb Bundh Lake. The suite of factors comprising dissolved oxygen, pH, temperature, turbidity and total hardness has been proved as the best subset for estimating total nitrogen concentration. The models developed have been validated for total phosphorus and total nitrogen concentration. For total phosphorus, the model values were found to be very close to the measured values but the values varied widely for total nitrogen, championing the former as a very potent down-to-earth model. 相似文献