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21.
Basant Kumar Jha 《Astrophysics and Space Science》1991,185(1):129-135
The effects of magnetic field and mass transfer on the flow of an elasto-viscous fluid past an infinite vertical plate, when the plate is moving with uniform velocityU, are discussed. The magnetic lines of force are assumed to be fixed relative to the plate. The Laplace transform method is used to obtain the expression for velocity. The effect of various parameters, occurring into the problem, is discussed with the help of tables. 相似文献
22.
An analytical study is performed to examine the heat source characteristics on the free-convection and mass transfer flow past an impulsively started infinite non-conducting vertical plate of a viscous, incompressible electrically-conducting fluid under the action of a uniform magnetic field through porous medium. The effects of various parameters on the velocity field are extensively discussed. 相似文献
23.
A statistical analysis of the contemporary (1954-1975) solar flare particle events has been made for the parametersF (integrated, proton fluence in cm-2 in an event with kinetic energy above 10 MeV) andR
0 (the characteristic rigidity). These data are compared with the long-term averaged values determined from stable- and radio-nuclide
measurements of lunar samples. The analysis shows that the ancient solar flare proton spectrum was harder (higher R0 values) compared to that observed in contemporary flares. A similar analysis can not be made for the mean long-term averaged
flux (ˉJ, cm-2 S-1), since the contemporary averages suffer from an uncertainty due to the statistics of a single event. However, the average
flux estimates for time durations 〈T〉 exceeding 103 yr, are free from such uncertainties. The long-term averaged ˉJ values obtained over different time scales (104 - 106 yr) suggest a possible periodic variation in solar flare activity, with enhanced flux level during the last 105 yr. The available data rule out the occurrence of giant flares, with proton fluence exceeding 1015 cm-2 during the last million years. 相似文献
24.
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
25.
26.
Sunil K. Jha 《洁净——土壤、空气、水》2012,40(12):1392-1400
The geochemical characteristics and the spatial distribution of the fluoride were studied in the soils of Indo‐Gangetic plains using multivariate analysis. The fluoride (F) distribution in soil profiles and surface soil (0–15 cm) samples were studied. It was found that total fluoride (TF) in the profiles ranged from 248 to 786 mg kg?1 with a mean of 515.1 mg kg?1 whereas CaCl2 extractable soluble fluoride (FCa) was found to be in the range of 1.68 to 99.1 mg F kg?1 soil. On the other hand, in surface soils, the TF and FCa ranged from 118 to 436 mg kg?1 with a mean of 251.2 mg kg?1 and 1.01 to 5.05 mg kg?1 with a mean of 2.12 mg kg?1, respectively, in the study area. The principal component analysis revealed that the natural weathering of fluoride bearing rock and minerals, various ion‐exchange and dissolution processes in the soil, alkalinity, sodium adsorption ratio, calcium (Ca), magnesium (Mg), and clay contents of the soil are responsible for high fluoride occurrence in the area. The fluoride contamination index developed by using these factors could explain more than 76% variance of F contamination due to FCa in soils. The interpolated kriged map of FCa in surface soil indicated a distinct loop of 1.0–2.0, 2.0–3.0, 3.0–4.0, and >4.0 mg kg?1. 相似文献
27.
A landslide susceptibility zonation (LSZ) map helps to understand the spatial distribution of slope failure probability in
an area and hence it is useful for effective landslide hazard mitigation measures. Such maps can be generated using qualitative
or quantitative approaches. The present study is an attempt to utilise a multivariate statistical method called binary logistic
regression (BLR) analysis for LSZ mapping in part of the Garhwal Lesser Himalaya, India, lying close to the Main Boundary
Thrust (MBT). This method gives the freedom to use categorical and continuous predictor variables together in a regression
analysis. Geographic Information System has been used for preparing the database on causal factors of slope instability and
landslide locations as well as for carrying out the spatial modelling of landslide susceptibility. A forward stepwise logistic
regression analysis using maximum likelihood estimation method has been used in the regression. The constant and the coefficients
of the predictor variables retained by the regression model have been used to calculate the probability of slope failure for
the entire study area. The predictive logistic regression model has been validated by receiver operating characteristic curve
analysis, which has given 91.7% accuracy for the developed BLR model. 相似文献
28.
Biraja Kumar Sahu Mehmuna Begum M.K. Khadanga Dilip Kr Jha N.V. Vinithkumar R. Kirubagaran 《Marine pollution bulletin》2013,66(1-2):246-251
Port Blair is the capital city of Andaman & Nicobar Islands, the union territory of India. More than 50% of the population of these islands lives around Port Blair Bay. Therefore the anthropogenic effects in the bay water were studied for monitoring purpose from seven stations. Physico-chemical parameters of seawater were analyzed in samples collected once in every 3 months for 2 years from seven sampling stations located in Port Blair Bay, South Andaman Island to evaluate the spatial and tidal variation. Cluster analysis and factor analysis were applied to the experimental data in an attempt to understand the sources of variation of physico-chemical parameters. In cluster analysis, the stations Junglighat Bay and Phoenix Bay having high anthropogenic influence formed a separate group. The factors obtained from factor analysis indicated that the parameters responsible for physico-chemical variations are mainly related to land run-off, sewage outfall and tidal flow. 相似文献
29.
Surendra Kumar Jha J. P. Shrivastava C. L. Bhairam 《Journal of the Geological Society of India》2012,79(2):117-134
Clays associated with the Precambrian unconformity-related (sensu lato) uranium mineralization that occur along fractures of Rohini carbonate, Bandai sandstone and clay-organic rich black carbonaceous
Gorakalan shale of the Sonrai Formation from Bijawar Group is significant. Nature and structural complexity of these clays
have been studied to understand depositional mechanism and palaeoenvironmental conditions responsible for the restricted enrichment
of uranium in the Sonrai basin. Clays (<2 μm fraction) separated from indurate sedimentary rocks by disaggregation, chemical
treatment and centrifugation were examined using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Presence
of tv-1M type illite is inferred from the Rohini and Bandai Members of the Sonrai Formation, indicative of high fluid/rock
interaction and super-saturation state of the fluids available in proximity with the uranium mineralization. It is observed
that the Sonrai Formation is characterized by kaolinite > chlorite > illite > smectite mineral assemblages, whereas, Solda
Formation contains kaolinite > illite > chlorite clays. It has been found that the former mineral assemblage resulted from
the alteration process is associated with the uranium mineralization and follow progressive reaction series, indicating palaeoenvironmental
(cycles of tropical humid to semi-arid/arid) changes prevailed during maturation of the Sonrai basin. The hydrothermal activity
possibly associated with Kurrat volcanics is accountable for the clay mineral alterations. 相似文献
30.
Neerja Jha Pauline Sabina K. Rajni Tewari N. C. Mehrotra 《Journal of the Geological Society of India》2011,77(2):137-148
42 genera of palynomorphs have been reported from the qualitative and quantitative analysis of the palynoflora from both open
cast mine and bore holes viz., Ballarpur open cast mine, Durgapur open cast mine and Bore hole CMWNM-57 on barrier between
Kawadi/Majri open cast and Hindustan Lalpeth Colliery from the Wardha valley coalfield of Wardha basin. Two palynoassemblages
have been recorded i.e., an Upper Karharbari palynoassemblage comprising dominance of radial monosaccate genus Parasaccites and subdominance of nonstriate disaccate genus Scheuringipollenites and a Lower Barakar palynoassemblage consisting of dominance of Scheuringipollenites and subdominance of striate disaccates chiefly Faunipollenites, suggesting an Early Permian age (Late Sakmarian to Early Artinskian) to the sediments. It is further authenticated by the
occurrence of palynotaxa viz., Crucisaccites, Caheniasaccites, Indotriradites and Tiwariasporis. Upper Karharbari Formation has been demarcated for the first time in lithologically designated Barakar Formations in Ballarpur,
Durgapur, Majri and Hindustan Lalpeth Colliery while the sample 57/2 of bore hole CMWNM from Kawadi area may belong to the
Kamthi Formation on the basis of pinkish yellowish coarse grained to medium grained sandstone. An attempt has been made to
correlate these palynoassemblages with other Lower Gondwana basins of Early Permian affinity. 相似文献