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41.
Hydrochemical characteristics of groundwater in the plains of Phalgu River in Gaya, Bihar, India 总被引：1，自引：0，他引：1
Rajesh Kumar Ranjan AL. Ramanathan Purushothaman Parthasarathy Alok Kumar 《Arabian Journal of Geosciences》2013,6(9):3257-3267
Assessment of groundwater quality is essential to ensure sustainable use of it for drinking, agricultural, and industrial purposes. The chemical quality of groundwater of Gaya region has been studied in detail in this work to delineate the potable groundwater zones. A total of 30 groundwater samples and 2 surface water samples were collected in and around Gaya district of Bihar. The major cations follow the trend: Ca2+?>?Mg2+?>?Na+?>?K+. The domination of calcium ions in the groundwater is due to weathering of rocks. The K+ ranged between 0.2 and 47.95 ppm, suggesting its abundance the below desired limit; but some samples were found to be above permissible limit. K+ weathering of potash silicate and the use of potash fertilizer could be the source. The major anions abundance followed the order HCO 3 ? ?>?Cl??>?SO 4 2? ?>?NO 3 ? ?>?PO 4 3? . Dissolution of carbonates and reaction of silicates with carbonic acid accounts for the addition of HCO 3 ? to the groundwater and oxidation of sulphite may be the source of SO 4 2? . Principal component analysis was utilized to reflect those chemical data with the greatest correlation and seven major principal components (PCs) representing >80 % of cumulative variance were able to interpret the most information contained in the data. PC1, PC2 and PC3 reflect the hydrogeochemical processes like mineral dissolution, weathering and anthropogenic sources. PC4, PC5, PC6 and PC7 show monotonic, random and independent relationships. 相似文献
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Walied M. Alarif Ahmed Abdel‐lateff Sultan S. AL‐lihaibi Seif‐Eldin N. Ayyad Farid A. Badria Abdulmohsin A. Alsofyani Zeinab S. Abou‐Elnaga 《洁净——土壤、空气、水》2013,41(11):1116-1121
Two new marine steryl hexadecanoates, 3β‐hexadecanoylcholest‐5‐en‐7‐one ( 1 ) and 3β‐hexadecanoylcholest‐5‐en‐7β‐ol ( 2 ), along with seven known compounds, cholest‐5‐en‐3β‐yl‐formate ( 3 ), thymidine ( 4 ), indole‐3‐carboxaldehyde ( 5 ), 3β‐hydroxycholest‐5‐en‐7‐one ( 6 ), cholesterol ( 7 ), 22‐dehydrocholestrol ( 8 ), and 24‐methylenecholesterol ( 9 ), were isolated from the anthozoan black coral, Antipathes dichotoma. The structures of all isolated compounds were determined by interpretation of their spectral data 1D (1H, 13C and DEPT) and 2D (COSY, HSQC and HMBC) NMR, UV, IR, and MS. Compounds 1 – 5 were evaluated for their anticancer activities, employing four cancer panels; HepG2, WI 38, VERO, and MCF‐7. All tested compounds, except 4 , showed moderate activities. Compound 4 exhibited significant anticancer activity against VERO and MCF‐7, with IC50 20.5 and 20.2 µg/mL, respectively. 相似文献
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In 2011, a large repository of resting cysts of the toxic dinoflagellate Alexandrium catenella was discovered in the sediments of the Onapua/Opua inlet located off Tory Channel, Queen Charlotte Sound. The inlet is a potential source of infection for other areas, such as the major mussel-growing areas of Port Underwood and Pelorus Sound. This study aimed to establish whether the dinoflagellate was a new arrival in the Sounds or had existed unnoticed in this isolated embayment for some time. Alexandrium catenella cysts were identified to a depth of 20–21?cm within the sediment cores, corresponding to a date estimated by radioisotope (210Pb and 137Cs) and Pinus radiata pollen distribution to at least the mid 1970s. Over this time span, resident populations of A. catenella have not become established beyond the confines of Queen Charlotte Sound, suggesting it does not pose an imminent threat of doing so unless increasingly intense and prolonged blooms result in more widespread cyst dispersal. 相似文献
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Bijendra Kumar Asmaa Naaz Kriti Shukla Chandravir Narayan Govind Singh Alok Kumar AL Ramanathan Anshumali 《Journal of the Geological Society of India》2016,87(2):227-235
The systematic and comprehensive geochemical analysis of fluoride (F) in twenty agricultural soil samples was carried out to understand spatial variability, mechanism of retention and release, and the areas of potential risk due to high concentrations of F in soil around Sidhi District, Central India. The spatial variations in physico-chemical parameters revealed significant difference in the methods of cultivation due to geomorphological constraints, availability of surface water and ground water etc., in the study area. The north and small pocket in central Sidhi were rich in fertile soils due to availability of surface and ground water. The southern and eastern Sidhi were rainfed areas, hence, the monocropping system by traditional methods showed less impact on the soil physico-chemical parameters. The soil F varied from 366.94 to 1178 mg/kg and 2-4 times greater than the background soil value (320 mg/kg) of the world. The pollution indexes were > 1 indicating prevalence of elevated soil fluorine. 相似文献
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This study simulates optical depth of marine warm clouds for year 2001 based on interactively predicted aerosol concentrations with a global chemical transport model (CTM) driven by the ERA-40 re-analysis meteorological data. The simulated aerosol and cloud droplet number concentrations (CDNC) largely reproduce the variations between polluted and pristine marine environment as revealed by surface and aircraft measurements. By constraining cloud liquid water path (CLWP) with satellite microwave measurements, the simulated global and southern hemispheric aerosol optical depth (AOD) and cloud optical depth (COD) are well within 10% of the observed values. As a result of larger anthropogenic aerosol loadings over the northern oceans, the simulated CDNC and COD are, respectively, by 51 and 18% higher than those over the southern oceans, while the column-averaged droplet effective radius is 13% smaller. These simulated interhemispheric differences, while qualitatively consistent with satellite observations, are larger than the observations. Inclusion of drizzle effect improved the disparities but not entirely. The constrained CTM generally captures the seasonality in AOD and CLWP observations, and demonstrates that annual cycle of COD is dominated by CLWP. During winter monsoon the simulated and observed COD correlate more strongly with changes in AOD over the N. Indian Ocean. 相似文献
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New fieldwork, mineralogical and geochemical data and interpretations are presented for the rare-metal bearing A-type granites of the Aja intrusive complex(AIC) in the northern segment of the Arabian Shield. This complex is characterized by discontinuous ring-shaped outcrops cut by later faulting. The A-type rocks of the AIC are late Neoproterozoic post-collisional granites, including alkali feldspar granite, alkaline granite and peralkaline granite. They represent the outer zones of the AIC, surrounding a core of older rocks including monzogranite, syenogranite and granophyre granite. The sharp contacts between A-type granites of the outer zone and the different granitic rocks of the inner zone suggest that the AIC was emplaced as different phases over a time interval, following complete crystallization of earlier batches. The A-type granites represent the late intrusive phases of the AIC, which were emplaced during tectonic extension, as shown by the emplacement of dykes synchronous with the granite emplacement and the presence of cataclastic features. The A-type granites consist of K-feldspars, quartz, albite, amphiboles and sodic pyroxene with a wide variety of accessory minerals, including Fe-Ti oxides, zircon, allanite, fluorite, monazite, titanite, apatite, columbite, xenotime and epidote. They are highly evolved(71.3–75.8 wt% SiO_2) and display the typical geochemical characteristics of post-collisional, within-plate granites. They are rare-metal granites enriched in total alkalis, Nb, Zr, Y, Ga, Ta, REE with low CaO, MgO, Ba, and Sr. Eu-negative anomalies(Eu/Eu* = 0.17–0.37) of the A-type granites reflect extreme magmatic fractionation and perhaps the effects of late fluid-rock interactions. The chemical characteristics indicate that the A-type granites of the AIC represent products of extreme fractional crystallization involving alkali feldspar, quartz and, to a lesser extent, ferromagnesian minerals. The parent magma was derived from the partial melting of a juvenile crustal protolith with a mantle contribution. Accumulation of residual volatile-rich melt and exsolved fluids in the late stage of the magma evolution produced pegmatite and quartz veins that cut the peripheries of the AIC. Post-magmatic alteration related to the final stages of the evolution of the A-type granitic magma, indicated by alterations of sodic amphibole and sodic pyroxene, hematitization and partial albitization. 相似文献
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S. B. SIMON D. J. JOSWIAK H. A. ISHII J. P. BRADLEY M. CHI L. GROSSMAN J. ALÉON D. E. BROWNLEE S. FALLON I. D. HUTCHEON G. MATRAJT K. D. McKEEGAN 《Meteoritics & planetary science》2008,43(11):1861-1877
Abstract— Among the samples returned from comet 81P/Wild 2 by the Stardust spacecraft is a suite of particles from one impact track (Track 25) that are Ca‐, Al‐rich and FeO‐free. We studied three particles from this track that range in size from 5.3 × 3.2 μ to 15 × 10 μ. Scanning and transmission electron microscopy show that they consist of very fine‐grained (typically from ?0.5 to ?2 μ) Al‐rich, Ti‐bearing and Ti‐free clinopyroxene, Mg‐Al spinel and anorthite, with trace amounts of fine perovskite, FeNi metal and osbornite (TiN) grains. In addition to these phases, the terminal particle, named “Inti”, also contains melilite. All of these phases, with the exception of osbornite, are common in refractory inclusions and are predicted to condense at high temperature from a gas of solar composition. Osbornite, though very rare, has also been found in meteoritic refractory inclusions, and could have formed in a region of the nebula where carbon became enriched relative to oxygen compared to solar composition. Compositions of Ti‐pyroxene in Inti are similar, but not identical, to those of fassaite from Allende inclusions. Electron energy loss spectroscopy shows that Ti‐rich pyroxene in Inti has Ti3+/Ti4+within the range of typical meteoritic fassaite, consistent with formation under reducing conditions comparable to those of a system of solar composition. Inti is 16O‐rich, with δ18O?δ17O?‐40%0, like unaltered phases in refractory inclusions and refractory IDPs. With grain sizes, mineralogy, mineral chemistry, and an oxygen isotopic composition like those of refractory inclusions, we conclude that Inti is a refractory inclusion that formed in the inner solar nebula. Identification of a particle that formed in the inner solar system among the comet samples demonstrates that there was transport of materials from the inner to the outer nebula, probably either in a bipolar outflow or by turbulence. 相似文献
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Pratima Pandey S. Nawaz Ali AL. Ramanathan P.K. Champati ray G. Venkataraman 《地学前缘(英文版)》2017,8(4):841-850
Hamtah and Chhota Shigri are two nearby, well monitored glaciers of western Himalaya, lying in the same climatic zone and driven by the same climatic conditions. In this study, topographical characteristics of both the glacier have been explored to understand the role of topography in controlling the glacier response. Further, their topographical characteristics and possible response towards climatic variations have been compared with each other and also with that of the other glaciers in the basin to find out the suitability of these two glaciers to be considered as representative of the region. Multi sensor and multi temporal remote sensing data have been used to carry out to fulfill the objectives. It is found that being in the same climatic zone, the mean accumulation area ratio of Chhota Shigri is 54% and Hamtah is 11% between 1980 and 2014. In comparison to Hamtah, Chhota Shigri glacier has a small upslope area, low compactness ratio indicating the ability of the glacier to receive direct precipitation and solar radiation. The analysis revealed that the Chhota Shigri glacier has a closer resemblance with the other glaciers in the region than Hamtah glacier. Also, the topographical settings of Chhota Shigri glacier are suitable for recording and reflecting year-to-year climatic variations. 相似文献