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Sharma Kunwar Mrityunjai Dessirier Benoit Tsang Chin-Fu Niemi Auli 《Hydrogeology Journal》2023,31(4):873-891
Hydrogeology Journal - The generalized radial flow (GRF) model in well-test analysis employs noninteger flow dimensions to represent the variation in flow area with respect to radial distance from... 相似文献
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We report here for the first time the presence of the natural, toluene-soluble C60 and the toluene-insoluble high-pressure and temperature phase of fullerene C60 in the carbonaceous matter extracted from the iridium-rich layers of the intertrappean sediments of Anjar, India. The toluene-insoluble form of fullerene is formed at high-temperature and pressure (HPT) and is distinguished from normal fullerene by UV-visible and Fourier-transform infrared (FT-IR) spectroscopic techniques. The C60 fullerene has been identified by high-resolution electron-impact ionization mass spectrometric analysis, as well as by Fourier-transform infrared (FT-IR), UV-visible, and 13C-nuclear magnetic resonance (NMR) spectroscopy. In iridium-poor horizons of this section, fullerenes are absent, but complex hydrocarbons are sometimes present. The FT-IR spectroscopic studies on the insoluble fullerenes show strong absorption peaks at about 740 and 509 cm−1 and a number of weak peaks at 1380, 1300, 1205, 1120, 1000, 608, 554, and 441 cm−1, which are characteristic of a high-pressure and temperature C60 fullerene. The UV-visible spectra of the toluene-soluble fullerene, as well as the insoluble fullerene, show strong absorption bands at 270 and 348 nm, which are characteristic of pristine fullerene C60. The toluene-insoluble carbon-rich residue shows additional absorption bands at 710, 640, and 395 nm. These UV-visible bands independently confirm the presence of the high-pressure-temperature (HPT) phase of fullerene C60. Conditions of high-pressure and temperature required for formation of the HPT fullerene phase can be created by an energetic impact event. Therefore, the presence of HPT fullerene in the KT boundary layer at Anjar is linked to the impact event at the KT transition. 相似文献
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Kunwar Raghvendra Singh Rahul Dutta Ajay S. Kalamdhad Bimlesh Kumar 《Environmental Earth Sciences》2018,77(23):780
The present study centers on the investigation of surface water quality with the aid of quality indices and explores the application of a multi-objective decision-making method (TOPSIS) in arranging decisions for policy makers on the basis of overall ranking of the sampling locations. A case study has been performed on the Manas River, Assam (India). Water Quality Index (WQI) involving physico-chemical parameters, and heavy metal pollution index (HPI) and contamination index (CI) involving heavy metal influences were employed for water quality assessment. WQI graded two sampling locations “very poor” and all other locations “poor”. HPIs of all the locations were below the critical value of 100, but the CI depicted that two locations were “moderately contaminated”. Risk assessment to human health was done using hazard quotient and hazard index. Cluster analysis (CA) demonstrated site similarity by grouping the relatively more polluted and less polluted (LP) sites into two major clusters. However, there surfaced difficulty in discerning the overall water quality, as all the three quality indices included different parameters and contradicted each other. A multi-objective decision-making tool, TOPSIS was therefore employed for ranking the locations on the basis of their relative pollution levels. The novelty of the study reflects in the identification of the relatively more or relatively less polluted sites within the same cluster in CA by the application of TOPSIS. The study justifies the effectiveness of TOPSIS method in prioritizing decisions in complex scenarios for policy makers. 相似文献
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A green-coloured phyllosilicate occurring on the walls of amygdaloidal cavities and along fractures in the Deccan Flood basalts
at Killari, Maharashtra, India, has been identified as iron-rich saponite with a chemical composition [Na0.60 K0.40 Ca0.47] {Mg2.05Fe3.95} (Si6.45Al1.55) O20(OH)4. In order to explore the possible application of this phyllosilicate for environmental management, we have carried out X-ray
photon spectroscopic (XPS) and diffuse reflectance spectroscopic (DRS) measurements on the dichromate solutions, in both the
untreated and treated form. The dichromate solution treated with the saponite samples show a remarkable capability not only
to adsorb hexavalent chromium but also effect a reduction of hexavalent to trivalent chromium at an efficiency of 75%. These
valence states of chromium were characterised unambiguously by XPS and DRS spectra collected at room temperature. Our studies
show that Killari saponite is capable of reducing Cr (VI) to Cr (III). The ferrous saponite in Deccan Flood basalts could
therefore be a useful mineral in environmental management in areas affected by Cr (VI) effluents. 相似文献
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Ripu M. KUNWAR Laxmi MAHAT Lila N. SHARMA Keshab P. SHRESTHA Hiroo KOMINEE Rainer W. BUSSMANN 《山地科学学报》2012,9(5):589-600
Underutilized plant species help to alleviate common food insufficiencies by providing alternative food supply. They also complement primary health care, furnishing raw materials where the cultivation of staple cereal crops is least feasible and health care is pursued indigenously. Research and promotion of extraction, utilization, and conservation of underutilized species lead to exploration of new staple crops and motivate people to consume in a sustainable manner. The present study describes the current status, uses, and management of underutilized plant species in Far West Nepal. The relative importance of 49 underutilized plant species was computed employing a Relative Importance (RI) technique. The use-values assigned to the species fall into six use-categories: beverage, fodder, food & edible, medicinal, vegetable and veterinary. A total of 22 species appeared in multiple use-categories, while the rest were characterized by a single use-category. Based on relative importance and frequency, Ficus semicordata, Debregesia longifolia, Girardinea diversifolia, Hydrocotyle nepalensis, Garuga pinnata, Aloe vera and Pyrus pashia offer the most potential for future. Underutilized plants proved important to folk medicine and food. These species persist because they remain useful to local people as means of subsistence, production, and primary health care. The findings are important so far as they point up the role of underutilized plants in national food security policy and health care, spelling out their potentialities and cross cutting relationships. 相似文献
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Kunwar Mrityunjai Sharma Debanjan Guha Roy Praksh Kumar Singh Lakshmi Kant Sharma Trilok Nath Singh 《Arabian Journal of Geosciences》2017,10(16):362
Understanding the flow behavior through fractures is critically important in a wide variety of applications. In many situations, the fluid flow can be highly irregular and non-linear in nature. Numerical simulation can be employed to simulate such conditions which are difficult to replicate in laboratory experiments. Therefore, a parametric study has been conducted on the fluid flow through micro-fracture over a large range of inlet pressure, fluid density, fluid viscosity, temperature, joint roughness coefficient (JRC), and fracture using finite element analysis. Irregular fracture profiles were created using Barton’s joint roughness coefficient. The Navier-Stokes (NS) equation was used to simulate the flow of water in those micro-fractures. The result showed that the fracture, fluid, and ambient conditions have a wide and varied effect on the fluid flow behavior. The interrelationship between these parameters was also studied. The model simulation provided result in the form of velocity and pressure drop profile, which can be used to determine the behavior of flow under different condition. The volumetric flow was calculated for each condition and has been plotted against the corresponding parameter to study the interrelationship. 相似文献
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