Geochemical analyses of termite mounds as a prospecting tool for tin deposits in Bastar,MP—a preliminary study     

K Surya Prakash Rao  S V Raju 《Journal of Earth System Science》1984,93(2):141-148

Tin deposits in the form of cassiterite occur in precambrian zoned pegmatite bodies intrusive into Archean metabasic and metasedimentary rocks in Bastar, MP. The associated economic minerals include columbite-tantalite, lepidolite, beryl etc. As a major part of the area is covered by a thick overburden, termite mounds have been used as geochemical sampling medium in view of their significant potentiality in tropical areas with overburden, and also because of the low cost and ease of sampling. Though many elements have been used as pathfinders for tin, tin itself acts as the best indicator of its deposits. The present work has given encouraging results, and therefore can be applied for tin prospecting and possibly for heavy metals like Nb, Ta, W, etc., in this and other areas where termite mounds have a good spatial distribution.  相似文献   

Natural radioactivity distribution studies in Trivandrum district,Kerala, India     

G. K. Raju  John Mathai  G. R. Ravindra Kumar  N. G. K. Nair 《Journal of Earth System Science》1986,95(3):397-407

The distribution pattern of radioactive minerals in Trivandrum district of Kerala has been investigated. The surface radioactivity was measured employing a jeep-mounted four-channel gamma-ray spectrometer coupled to a high volume Na I (T1) crystal detector. The distribution of radioactivity has been correlated with the corresponding litho-units and major structures of the study area. The total countrate from sedimentaries including beach sands and pegmatite rich zones (～ 3,500 CPS) are significantly higher than that of the laterites and gneisses which are substantiated by laboratory studies.  相似文献   

Chemical distinction between replacement and magmatic granitic rocks     

R. Dhana Raju  J. S. R. Krishna Rao 《Contributions to Mineralogy and Petrology》1972,35(2):169-172

Utilising about 170 chemical analyses of granitic rocks of proved origin from different parts of the world, a new field is suggested in the Ca-Na-K (ionic weight per cent) trilinear diagram to distinguish the replacement from the magmatic type.  相似文献   

Origin of kondakarla lake in Visakhapatnam district,Andhra Pradesh     

K. N. Prudhvi Raju  K. B. Mahalakshmi  R. Vaidyanadhan 《Journal of the Indian Society of Remote Sensing》1982,10(2):63-66

Kondakarla lake is the largest natural fresh water lake in Visakhapatnam district. The lake is thought to have been formed in stages. There might have been in the past a ‘U’ shaped rim of hills enclosing a basin with a minor drainage system. With the reduction of hills in relative relief, the drainage got obliterated because of excessive deposition of alluvium leaving a gently sloping piedmont and a central shallow depression. An old course of the Sarada river entered the lake and there are evidences in field indicating the old course having got in and got out of the lake, in the absence of a few geomorphic units along the foot-slopes of the hills. These geomorphic units appear to have been removed by the swerving meander loops of the old course. Again, there are a series of four sandy islands in the lake, the configuration and disposition of which indicate deposition in the inside of the meander loops as point bar deposits, while the old course migrated towards southeast of the basin. The lake is thought to have been farmed in the gently sloping basin partially deepened perhaps by migrating course of tha Sarada river. Aggradation at the northestern part besides cutting off of the meander loop, has created a barrier of low relief resulting in a narrow long basin of internal drainage. Neither the structural trend of the hills nor any other features indicate synclinal or anticlinal troughs, ruling out any structural origin for this lake.  相似文献   

Phylogenetic analysis and biological characteristic tests of marine bacteria isolated from Southern Ocean (Indian sector) water     

GUPTA Pratibh  BALAJI Raju  PARANI M  CHANDRA T S  SHUKLA P  KUMAR Anil  BANDOPADHYAY Rajib 《海洋学报(英文版)》2015,34(8):73-82

Fifty-seven bacteria were isolated from Southern Ocean(Indian sector) water samples which were collected from different latitude and longitude of the ocean. All the isolates were able to grow at 4°C, 20°C, 37°C and tolerable Na Cl concentration up to 13.5%(w/v). 29 out of 57 isolates were identified using 16 S rDNA amplification and the sequences were submitted to National Center for Biotechnology Information(NCBI). All the isolates were classified by using Ribosomal Database Project(RDP) and found that isolates belongs to Proteobacteria and Bacteriodes. The average G+C content was 56.4%. The isolates were screened for the presence of extracellular enzymes, viz. amylase, catalase, urease, esterase, lipase and protease. The disc diffusion method is used to screen antibiotic production by the isolates against four pathogenic bacteria, viz. Salmonella typhimurium(NCIM 2501),Staphylococcus aureus(NCIM 2122), Bacillus subtilis(NCIM 2193), and Pseudomonas aeruginosa(NCIM 2036).Nine out of 29 were found to be antibiotic producer.  相似文献   

Non-existence of kinks in a modified gravity     

D. R. K. Reddy  Shobhan Babu  P. Raju 《Astrophysics and Space Science》2014,353(1):275-278

Spherically symmetric kink space-time is considered in the framework of f(R,T) gravity proposed by Harko et al. (Phys. Rev. D 84:024020, 2011) in the presence of a cloud of massive strings with perfect fluid. Solving the field equations of this modified theory of gravity, we observe that cosmic strings and perfect fluid do not survive in this theory of gravitation and in this particular space-time. Hence a vacuum kink model, which is asymptotically flat, is presented.  相似文献   

Numerical simulation of tropical cyclone thane: role of boundary layer and surface drag parameterization schemes     

M. Sateesh  C. V. Srinivas  P. V. S. Raju 《Natural Hazards》2017,89(3):1255-1271

In the recent times, several advanced numerical models are utilized for the prediction of the intensity, track and landfall time of a cyclone. Still there are number of issues concerning their prediction and the limitation of numerical models in addressing those issues. The most pertinent question is how intensive a cyclone can become before it makes a landfall and where the cyclone moves under the ambient large-scale flow. In this paper, detailed study has been carried out using Weather Research Forecast model with two boundary schemes to address the above question by considering a recent tropical cyclone in Bay of Bengal region of North Indian Ocean. In addition, the impact of the surface drag effect on the low-level winds and the intensity of the cyclone are also studied. The result reveals that large differences are noted in the ocean surface fluxes between YSU and MYJ with MYJ producing relatively higher fluxes than YSU. It is found that the YSU scheme produced a better simulation for the THANE cyclone in terms of winds, pressure distribution and cloud fractions. Comparison with available observations indicated the characteristics of horizontal divergence, vorticity and vector track positions produced by YSU experiment are more realistic than with MYJ and other experiments. However, when the drag coefficient is changed as 0.5 or 2.0 from the default values, appreciable changes in the surface fluxes are not noticed. A maximum precipitation is reported in YSU as compared to the MYJ PBL scheme for the tropical cyclone THANE.  相似文献   

Estimation of Cd,Pb and flame retardants in electric mosquito bat using EDXRF,ICP-OES,AAS and GC–MS     

B. Divya  S. Harish  K. Ramaswamy  M. Kishorebabu  N. Raju  R. Govindaiah  U. Rambabu  N. R. Munirathnam 《International Journal of Environmental Science and Technology》2017,14(12):2603-2612

In the present study, investigated the concentrations of hazardous substances such as Pb, Cd and polybrominated flame retardants present in an electric mosquito bats, which are used for trapping the mosquitoes in the domestic areas. China has captured a big share of mosquito bat market in India and penetrated deep into rural areas also. The presence of hazardous substances is fatal to environment and human beings. Hence, the concentrations of hazardous substances present in the bats need to be estimated accurately. The dismantled homogeneous samples were subjected to estimate the toxic metals like cadmium and lead by using energy-dispersive X-ray fluorescence spectroscopy, inductively coupled plasma optical emission spectroscopy and atomic absorption spectroscopy for comparison. The flame brominated retardants were tested using gas chromatography–mass spectrometer. The analytical data obtained from the power supply wires of the bat suggest that the concentration levels of cadmium found to be below the detection limits. Whereas the lead content has higher in the range of 3574–7575 ppm than the permissible limits set by the e-waste rule, i.e. 1000 ppm. Moreover, the high amount of lead (>80,000 ppm) was obtained in the printed circuit board apart from power supply wires of mosquito bat. The content of brominated flame retardants in mosquito bat was estimated to be within the limits of e-waste rule. Considering their significant high hazardous metals content, coupled with their large quantities of mosquito bats used in the country, there is a need to control the hazardous waste of mosquito bats.  相似文献