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1.
Using the global positioning system (GPS) measurements, the total electron content (TEC) at station Bangalore (13.02°N, 77.57°E geographic; 04.44°N, 150.84°E geomagnetic), lying at the equatorial region, and station Lucknow (26.91°N, 80.95°E geographic; 17.96°N, 155.24°E geomagnetic), lying at equatorial ionospheric anomaly (EIA) crest region, have been estimated for the year 2012–2013. In order to evaluate the International Reference Ionosphere (IRI) model regarding simulation/modeling of ionospheric studies specially at equatorial and EIA crest regions, we have compared the TEC derived from the recent version of the IRI-2012 model and the older IRI-2007 with its three topside options, namely IRI-NeQuick (IRI-NeQ), IRI-2001, and IRI01-corr, with that of GPS-TEC over Bangalore and Lucknow. For the EIA station Lucknow, the IRI-2012 model with IRI-NeQ and IRI01-corr topside is found in good agreement with GPS-TEC during summer and equinox season, while the IRI-2012 model for all three topside options significantly overestimates the GPS-TEC during winter season. The IRI-2001 topside overestimates the GPS-TEC over both the stations during all seasons. The anomalous difference between the IRI-2012 model prediction and ground-based GPS-TEC in daytime hours during the winter season observed at Lucknow could be attributed to discrepancies in the slab thickness predicted by the model, which is more during the winter season as compared to summer and equinox. These large discrepancies in the slab thickness predicted by the IRI-2012 as well as the IRI-2007 model during the winter season have been supported by using the foF2 data from Constellation Observing System for Meteorology, Ionosphere, and Climate radio occultation-based measurements. We also observed that the discrepancies in the recent IRI-2012 model with respect to GPS-TEC are found to be slightly larger than those with the older IRI-2007 model over the EIA region Lucknow. However, over the equatorial region Bangalore, the discrepancy with the older model IRI-2007 was found to be larger than with the recent IRI-2012 model. This suggests that the performance of the IRI-2012 model is poorer than the IRI-2007 model at the EIA region while better at equatorial region, and that further improvements in the IRI-2012 models are required particularly in the low-latitude and EIA regions. The GPS-TEC showed disappearance of the winter anomaly during 2012–2013, while the IRI model failed to predict the disappearance of winter anomaly. 相似文献
2.
Biosorption of heavy metals by a marine bacterium 总被引：1，自引：0，他引：1
Heavy metal chelation property of exopolysaccharide produced by Enterobacter cloaceae, a marine bacterium, isolated from the West Coast of India, is reported in this paper. The exopolysaccharide demonstrated excellent chelating properties with respect to cadmium (65%) followed by copper (20%) and cobalt (8%) at 100 mg/l heavy metal concentration. However, it could not chelate mercury. A comparative study of the percentage biosorption of the above mentioned metals is presented here. 相似文献
3.
T. Madhavi T. Satish Kumar M. A. Rasheed G. Kalpana D. J. Patil A. M. Dayal 《Journal of the Geological Society of India》2009,74(1):7-15
A study was carried out to test the usefulness of surface geochemical methods as regional evaluation tools in petroliferous
region of the Mehsana block, North Cambay Basin. A suite of 135 soil samples collected from the depth of 2.5 m, were analyzed
for adsorbed light gaseous hydrocarbons and carbon isotopes (δ13Cmethane and δ13Cethane). The light gaseous hydrocarbon analysis show that the concentration ranges 402 ppb, 135 ppb, 70 ppb, 9 ppb and 18 ppb of
C1, C2, C3, iC4 and nC4, respectively. The value of carbon isotopic ranges of methane −29.5 to −43.0‰ (PDB) and ethane −19.1 to −20.9‰ (PDB). This
data, when mapped, indicates patterns coinciding with major known oil and/or gas field of Sobhasan/Linch in this study area.
The existence of un-altered petroliferous microseeps of catagenetic origin is observed in the study area. A regional study,
such as the one described here, can provide important exploration facts concerning the regional hydrocarbon potential in a
block. This method has been confirmed and can be applied successfully in frontier basins. 相似文献
4.
M. Lakshmi M. A. Rasheed T. Madhavi B. Rajeswara Reddy M. S. Kalpana D. J. Patil A. M. Dayal 《Journal of the Geological Society of India》2012,80(5):641-652
Surface adsorbed gas surveys and geo-microbiological surveys are known techniques of petroleum exploration and aim towards risk reduction in exploration by way of identifying the areas warm with hydrocarbons and to establish intense exploration priorities amongst the identified warm areas. The present investigation aims to explore correlation between the adsorbed gas distribution pattern with the distribution of the counts of methane, ethane, propane and butane microbial oxidizers in the sub soil samples to establish the role of the latter in identifying the upward migration of hydrocarbons especially in the known petroliferous Krishna-Godavari Basin, India. A total of 135 soil samples were collected near oil and gas fields of Tatipaka, Pasarlapudi areas of Krishna Godavari Basin, Andhra Pradesh. The soil samples were collected from a depth of 2?C2.5 m. The samples collected, were analyzed for indicator hydrocarbon oxidizing bacteria, adsorbed light gaseous hydrocarbons and carbon isotopes (??13Cmethane). The microbial prospecting studies showed the presence of high bacterial population for methane (3.94 × 105 cfu/gm), ethane (3.85 × 105 cfu/gm), propane (4.85 × 105 cfu/gm) and butane oxidizing bacteria (3.63 × 105 cfu/gm) in soil samples indicating microseepage of hydrocarbons. The light gaseous hydrocarbon analysis showed 83 ppb, 92 ppb, 134 ppb, 187 ppb and 316 ppb of C1, C2, C3, nC4 and nC5, respectively, and the carbon isotopic composition of ??13C1 of the samples ranged between ? 36.6 ?? to ?22.7?? (Pee Dee Belemnite) values, which presents convincing evidence that the adsorbed soil gases collected from these sediments are of thermogenic origin. Geo-microbial prospecting method and adsorbed soil gas and carbon isotope studies have shown good correlation with existing oil/ gas fields of K.G basin. Microbial surveys indicating microseepage of hydrocarbons can, therefore, independently precede other geochemical and geophysical surveys to delineate areas warm with hydrocarbons and mapped microbiological anomalies may provide focus for locales of hydrocarbon accumulation in the K.G basin. 相似文献
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6.
P. Lakshmi Srinivasa Rao D. Srinu M. A. Rasheedd M. S. Kalpana D. J. Patil A. M. Dayal 《Journal of the Geological Society of India》2013,82(6):666-674
Direct correlation have been observed between certain trace element and hydrocarbon anomalies in the near subsurface soils of Vindhyan basin, India. This relationship with hydrocarbon is very useful in hydrocarbon exploration. 52 soil samples from Vindhyan basin were collected from a depth of 2.5m. All the soil samples were analyzed for light hydrocarbon, isotope and trace element concentrations. The adsorbed light gaseous hydrocarbon analyses show the presence of methane (8–328 ppb), ethane (0–27 ppb) and propane (0–11 ppb) respectively and these values indicate the presence of hydrocarbon micro-seepage in the study area. The carbon isotopic values determined for methane and ethane for these soil samples are (?26.41 to ?47.70 ‰ PDB) and (?20.07 to ?35.30 ‰ PDB) respectively and they are thermogenic in nature. The trace element concentrations of nickel (33–220 ppm), vanadium (72–226 ppm), copper (20–131 ppm), chromium (94–205 ppm), zinc (66–561 ppm) and cobalt (9–39 ppm) have higher than the normal concentrations in soils. Trace element concentrations are used to plot with the data obtained from light gaseous hydrocarbon concentrations and carbon isotopic values of soil samples of the Vindhyan basin. Trace element anomalies have been observed around the hydrocarbon anomalies in the study area. 相似文献
7.
Manish Kumar Kalpana Kumari AL. Ramanathan Rajinder Saxena 《Environmental Geology》2007,53(3):553-574
Punjab is the most cultivated state in India with the highest consumption of fertilizers. Patiala and Muktsar districts are
two agricultural dominated districts of Punjab located in extreme south-east and south-west of the state. This paper highlights
temporal variations of the groundwater quality and compares its suitability for irrigation and drinking purpose in these two
districts. Water samples were collected in March and September 2003, representing the pre-monsoon and post-monsoon seasons,
respectively. Water samples were analysed for almost all major cations, anions, dissolved heavy metals and turbidity. Parameters
like sodium adsorption ratio, % sodium, residual sodium carbonate, total hardness, potential salinity, Kelley’s ratio, magnesium
ratio, index of base exchange and permeability index were calculated on the basis of chemical data. A questionnaire was also
used to investigate perception of villagers on taste and odour. Comparison of the concentration of the chemical constituents
with WHO (world health organization) drinking water standards of 2004 and various classifications show that present status
of groundwater in Patiala is better for irrigation and drinking purposes except for a few locations with a caution that it
may deteriorate in near future. In Muktsar, groundwater is not suitable for drinking. Higher total hardness (TH) and total
dissolved solids at numerous places indicate the unsuitability of groundwater for drinking and irrigation. Results obtained
in this forms baseline data for the utility of groundwater. In terms of monsoon impact, Patiala groundwater shows dilution
and flushing but Muktsar samples show excessive leaching of different chemical components into the groundwater leading to
the enrichment of different anions and cations indicating pollution from extraneous sources. No clear correlation between
the quality parameters studied here and perceived quality in terms of satisfactory taste response were obtained at electrical
conductivity values higher than the threshold minimum acceptable value. 相似文献
8.
Simulation technique for whistler mode signal propagating through inhomogeneous plasma using WKB approximation has been developed (Singh, K., Singh, R.P., Ferencz, O.E., 2004. Simulation of whistler mode propagation for low latitude stations. Earth Planet Space 56, 979-987). In the present paper, we have used it for the analysis of recorded signals at low latitudes and estimated the nose frequency, which is not observed on the dynamic spectra. At low latitudes nose frequency is ∼100 kHz or more and therefore it is absent in the dynamic spectra due to attenuation of the signal at higher frequencies. The importance of nose frequency is in determining the exact path of propagation, which is required in probing of ambient medium. It is shown that the method permits to study the nose frequency variation, it can be used to deduce physical parameters as the global electric field. A case study permits to get a reasonable value of the electric field, which up to now could not be done at very low latitude. 相似文献
9.
The present work reports biological neutralization of chlor-alkali industrial effluent by an alkaliphilic bacterium, isolated from the Gujarat coast, which was identified as Enterococcus faecium strain R-5 on the basis of morphological, biochemical and partial 16S rRNA gene sequencing. The isolate was capable of bringing down the pH of waste water from 12.0 to 7.0 within 3 h in the presence of carbon and nitrogen sources, with simultaneous reduction in total dissolved solutes (TDS) up to 19-22%. This bacterium produced carboxylic acid, as revealed by FT-IR analysis, which facilitated neutralization of alkaline effluent. The presence of unconventional raw materials viz. Madhuca indica flowers or sugar cane bagasse as carbon and nitrogen sources could effectively neutralize alkaline effluent and thus making the bioremediation process economically viable. The time required for neutralization varied with size of inoculum. To the best of our knowledge, this is the first report on biological neutralization of a chlor-alkali industrial effluent. 相似文献
10.
B. Anu Radha M. A. Rasheed P. L. Srinivasa Rao M. S. Kalpana A. M. Dayal 《Journal of the Geological Society of India》2011,78(5):477-483
A geochemical study of surface sediments from Pranhita-Godavari Basin, Andhra Pradesh, India was carried out using light hydrocarbon
compounds to assess the hydrocarbon potential of the basin. Suite of 80 soil samples were collected from the depth of 2.5
m and analyzed for adsorbed light gaseous hydrocarbons namely methane (CH4), ethane (C2H6) and propane (C3H8) in Gas chromatograph. Compound specific Carbon isotope ratios for CH4 and C2H6 were also determined using GC-C IRMS (Gas Chromatograph Combustion Isotope Mass Spectrometer). The presence of moderate to
low concentrations of methane (CCH4 C_{CH_4 } : 1 to 138 ppb), ethane (H4{H_4 }: 1 to 35 ppb) and propane (CC3 H8 C_{C_3 H_8 } : 1 to 20 ppb) was measured in the soil samples. Carbon isotopic composition of d13 CCH4 \delta ^{13} C_{CH_4 } ranges between −27.9 to −47.1 ‰ and d13 CC2 H6 \delta ^{13} C_{C_2 H_6 } ranged between −36.9 to −37.2 ‰ (V-PDB) indicating that these gases are of thermogenic origin. Study of soil samples suggests
the area has good potential for hydrocarbon. 相似文献