Hydrobiological Parameters as an Indicator of Water Pollution in the Chilwa Lake,Gorakhpur     

K. Pandey  J. P. Shukla 《洁净——土壤、空气、水》1982,10(1):113-116

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Histological Changes in a Few Tissues of Notopterus notopterus Induced by Sublethal and Lethal Concentrations of Pulp,Paper and Mixed Pulp and Paper Wastes     

S. R. Verma  S. G. R. Shukla  R. C. Dalela 《洁净——土壤、空气、水》1979,7(1):77-86

In the present work, histological changes in the gill, liver, kidney and intestine of Notopterus notopterus, induced by pulp waste, paper waste and mixed pulp and paper waste, have been studied both at sublethal and lethal concentrations. The pulp waste produces much more histological changes both at sublethal and lethal concentrations in the gill, liver, kidney and intestine as compared to paper waste and mixed pulp and paper waste. The changes are much more remarkable in the case of sublethal concentration, as compared to a lethal concentration. In a sublethal concentration, the localized necrosis, atrophy and partial and total liquefaction of epithelial cells, pilaster cells, mucous cells of the gill, hepatic cells of the liver, mesenchymatous cells, renal tubule cells and Bowman's capsule of the kidney, mucosal and submucosal cells and blood vessels of intestine have been observed. In lethal concentration, the changes are much more marked in the gill, as compared to the liver, kidney and intestine. The histological changes, produced in the different types of cells and in the tissue as a whole, can be correlated with the different chemical components present in the pulp waste, paper waste and mixed pulp and paper waste.  相似文献   

Ice accumulation rate in Changme-Khangpu glacier,Sikkim     

P. N. Shukla  N. Bhandari  V. N. Nijampurkar  D. Kameswara Rao  V. M. K. Puri  Sanjiv Sharma 《Journal of Earth System Science》1983,92(3):255-260

Vertical profiles of¹³⁷Cs and²¹⁰Pb have been determined in a 9 m column of ice from accumulation zone of Changme-Khangpu glacier in north Sikkim valley.¹³⁷Cs activity varies from 4 to 22 dpm/ L. In many samples²¹⁰Pb occurs at a level of 20 to 65 dpm/ L which is much higher than the expected fallout value.¹³⁷Cs and²¹⁰Pb activities correlate well with each other but not with the dust content. Possibility of²¹⁰Pb production in the nuclear explosions is discussed. Several peaks appear in the depth profile of¹³⁷Cs and²¹⁰Pb which can be matched with Chinese atmospheric nuclear explosions with some phase difference if a uniform ice accumulation rate of 0.7 m per year is assumed since 1969.  相似文献   

Pseudo-dynamic approach of seismic active earth pressure behind retaining wall   总被引：4，自引：2，他引：4  

Deepankar Choudhury  Sanjay S. Nimbalkar 《Geotechnical and Geological Engineering》2006,24(5):1103-1113

Knowledge of seismic active earth pressure behind rigid retaining wall is very important in the design of retaining wall in earthquake prone region. Commonly used Mononobe-Okabe method considers pseudo-static approach, which gives the linear distribution of seismic earth pressure in an approximate way. In this paper, the pseudo-dynamic method is used to compute the distribution of seismic active earth pressure on a rigid retaining wall supporting cohesionless backfill in more realistic manner by considering time and phase difference within the backfill. Planar rupture surface is considered in the analysis. Effects of a wide range of parameters like wall friction angle, soil friction angle, shear wave velocity, primary wave velocity and horizontal and vertical seismic accelerations on seismic active earth pressure have been studied. Results are provided in tabular and graphical non-dimensional form with a comparison to pseudo-static method to highlight the realistic non-linearity of seismic active earth pressures distribution.  相似文献   

Isprs Commission II Symposium: Geoinformation Connecting Societies     

Sanjay  Rana 《The Photogrammetric Record》2006,21(116):402-404

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Parallel propagation effects on low-frequency Hall current instability in a dusty plasma     

M. Rosenberg  P.K. Shukla 《Planetary and Space Science》2002,50(3):261-267

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Jeans Instability in Collisional Dusty Plasmas     

P.K. Shukla  Frank Verheest 《Astrophysics and Space Science》1998,262(2):157-162

It is shown that dust-neutral and ion-neutral drags can produce instabilities of electrostatic waves in multicomponent self-gravitating dusty plasmas. Explicit expressions for the growth rates of the instabilities are presented. The relevance of our investigation to fragmentation of molecular dust clouds is discussed.  相似文献   

Waves and Instabilities in Magnetized Dusty Plasmas     

Padma K. Shukla 《Astrophysics and Space Science》1998,264(1-4):235-245

The status of waves and instabilities in magnetized dusty plasmas is summarized. The effects of an external magnetic field on low-frequency electrostatic and electromagnetic waves in dusty plasmas are discussed. The kinetic and hydrodynamic instabilities are shown to excite magnetized dusty plasma waves. The presence of the latter can give rise to an oscillatory wake-potential which can be responsible for the charged dust grain attraction. The relevance of our investigation to laboratory and space plasmas has been pointed out. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Nonlinear Drift-Alfvén Waves in Relativistically Hot Nonuniform Electron-Positron Plasmas     

O.G. Onishchenko  O.A. Pokhotelov  P.K. Shukla  L. Stenflo 《Astrophysics and Space Science》1998,262(3):249-262

The magnetic viscosity tensor is derived for a magnetized relativistic collisionless plasma with temperature gradients. By means of this tensor we deduce the nonlinear equations for drift–Alfvén waves in a relativistic electron-positron low plasma with density and temperature gradients. It is shown that our new equations have solutions in the form of dipolar vortices. The present results should be relevant to a number of astrophysical objects with strong electron-positron pair production, e.g. in pulsars as well as in accretion disks and jets.  相似文献   

HE 1127–1304: the largest radio quasar     

Sanjay Bhatnagar  Gopal Krishna  & L. Wisotzki 《Monthly notices of the Royal Astronomical Society》1998,299(2):L25-L28

By considering the propagation of low-amplitude magnetohydrodynamic waves in partially ionized plasmas, it is shown that the ion-neutral drift (ambipolar diffusion) induced by the waves can have specific effects on the molecular chemistry of cold material. The chemistry occurring in gas swept by Alfvén waves is described and it is shown that this leads to spatial variations in the deuterium fractionation ratios of, for example, HCO⁺ and N₂H⁺, on spatial scales of a few hundredths of a parsec, depending upon the fractional ionization of the ambient medium. The possibility of detecting interstellar Alfvén waves by molecular spectroscopy and their effect of producing small-scale chemical abundance gradients in molecular clouds are briefly discussed.  相似文献