Analysis of terrestrial naturally occurring radionuclides in soil samples from some areas of Sirsa district of Haryana,India using gamma ray spectrometry     

Rohit Mehra  Sandeep Kumar  Rajendra Sonkawade  N. P. Singh  Komal Badhan 《Environmental Earth Sciences》2010,59(5):1159-1164

The activity concentration and the gamma-absorbed dose rates of the terrestrial naturally occurring radionuclides (²³²Th, ²²⁶Ra and ⁴⁰K) were determined in soil samples collected from ten different locations of Sirsa district of Haryana, using HPGe detector based on high-resolution gamma spectrometry system. The range of activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the soil samples from the studied areas varies from 19.18 Bq kg⁻¹ (Moriwala) to 40.31 Bq kg⁻¹ (Rori), 59.43 Bq kg⁻¹ (Pipli) to 89.54 Bq kg⁻¹ (Fatehpur) and 223.22 Bq kg⁻¹ (Moriwala) to 313.32 Bq kg⁻¹ (SamatKhera) with overall mean values of 27.94, 72.75 and 286.73 Bq kg⁻¹ respectively. The absorbed dose rate calculated from activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K ranges between 8.84 and 18.58, 37.02 and 55.78, and 9.24 and 12.97 nGy h⁻¹, respectively. The total absorbed dose in the study area ranges from 60.40 to 82.15 nGy h⁻¹ with an average value of 70.12 nGy h⁻¹. The calculated values of external hazard index (H _ex) for the soil samples of the study area range from 0.36 to 0.49 with an average value of 0.42.  相似文献   

Geochemical characterization and heavy metal contamination of groundwater in Satluj River Basin   总被引：1，自引：0，他引：1  

Chander Kumar Singh  Kumari Rina  Ravi Prakash Singh  Saumitra Mukherjee 《Environmental Earth Sciences》2014,71(1):201-216

Groundwater, a renewable and finite natural resource, vital for man’s life, social and economic development and a valuable component of the ecosystem, is vulnerable to natural and human impacts. The aim of present study is to evaluate hydrogeochemical parameters and heavy metals in groundwater and to study their spatial distribution in the Rupnagar District of Punjab. The spatial distribution of physico-chemical parameters were studied using Arc GIS 9.2. It was observed that the concentration of parameters, such as NO₃, Cd, Cr, Mn and Pb was above permissible limit (World Health Organization, WHO) in southern part of the study area. The heavy metal pollution index (HPI) was calculated for all sampling locations and it was found much above the critical limit of pollution. Geochemical reaction models of selected water groups were constructed using Phreeqc. Geochemical modeling suggests that sodium has source other than halite-albite and calcium has alternate source other than gypsum-carbonate or silicates. It also suggests that evaporites, ion exchange, dissolution along with anthropogenic activities are controlling the hydro-geochemistry of groundwater in the region. Various indices, such as heavy metal pollution index, permeability index, sodium adsorption ratio, were studied to verify suitability of groundwater for drinking and irrigation.  相似文献   

Implementation of RISAT-1 Hybrid Polarimetric Decomposition Techniques and Analysis Using Corner Reflector Data     

P. V. Jayasri  K. Niharika  Manoj Joseph  H. S. V. Usha Sundari Ryali  C. V. Ramana Sarma  E. V. S. Sita Kumari  A. V. V. Prasad 《Journal of the Indian Society of Remote Sensing》2018,46(6):1005-1012

With recent advances in polarimetry, Synthetic Aperture Radar (SAR) with Hybrid–polarity architecture, a demonstration of compact polarimetry enabled larger swath coverage, reduced PRF and SAR system complexity as compared to fully polarimetric systems. The first Hybrid Polarimetric Space-borne SAR in Earth Observation orbit, India’s Radar Imaging Satellite (RISAT-1) is a new-fangled gateway to remote sensing user community for land and oceanic applications. In response to a right-circular polarized transmitted signal, based on the derived stokes vectors, Stokes parameters are estimated to produce several useful quantitative measures for generating polarimetric decomposed image. m-delta, m-chi and m-alpha polarimetric decomposition methods along with suitable weighting functions in terms of three principal components are implemented which maps Stokes parameters to RGB image space for representing odd bounce, even bounce and volume scattering targets. Various RISAT-1 Hybrid Fine Resolution Stripmap Single-Look Complex SAR datasets acquired over deployed corner reflectors at calibration site, Shadnagar have been considered over which different hybrid polarimetric decomposition techniques are implemented using in-house developed software. Further analysis produced encouraging results with standard point targets like dihedral and trihedral corner reflectors against distributed targets in the same scene to demonstrate the scattering mechanisms as per their characteristics when interacted with a polarized signal were presented in this paper.  相似文献   

Effect of linear waves on kinetic Alfvén wave localization and turbulent spectrum     

Anju Kumari  Nitin Yadav  R. P. Sharma 《Astrophysics and Space Science》2014,352(1):201-206

We have presented the localization of kinetic Alfvén wave (KAW) in intermediate β plasma (m _e /m _i ?β?1) by developing a model based on pump kinetic Alfvén wave and finite amplitude magnetosonic fluctuations. When KAW is perturbed by these background magnetosonic fluctuations, filamentary structures of KAW magnetic field are formed. First, a semi analytical model based on paraxial approximation has been developed to understand this evolution process. Localized structures and magnetic fluctuation spectrum of KAW has also been studied numerically for finite frequency of KAW. The calculated magnetic fluctuation spectrum follows two types of scalings. Above the proton gyroradius scale lengths (in inertial range), spectrum follows Kolmogorovian scaling. Below this scale dispersion starts and the spectrum steepens to about \(k_{x}^{-2.5}\) . The result shows the steepening of power spectra which can be responsible for particle acceleration in solar wind due to the energy transfer from larger to smaller lengthscales. Obtained magnetic turbulent spectra are consistent with observations of Cluster spacecraft in solar wind.  相似文献   

A restudy of the Ostracoda <Emphasis Type="Italic">Cypris cylindrica</Emphasis> Sowerby (in Malcolmson, 1840) from the Deccan Intertrappean beds (late cretaceous) of Lakshmipur,Kachchh, Gujarat     

S. C. Khosla  M. L. Nagori  S. R. Jakhar  A. S. Rathore  Manisha Kumari 《Journal of the Geological Society of India》2009,74(5):579-584

Cypris cylindrica was originally described by Sowerby (in Malcolmson, 1840) from the Deccan Intertrappean sedimentary beds of the Sichel Hills, Andhra Pradesh. Whatley and Bajpai (2000) recorded the species during recent years from the Intertrappean of Lakshmipur, Kachchh district, Gujarat and stated that Kachchh specimens are identical with the types of the species housed in the Natural History Museum (NHM), London. They recorded the species as Mongolianella cylindrica. The species, however, lacks distinctive shape and hinge structure of Mongolianella and on the contrary closely resembles Stenocypris cylindrica major (Baird, 1859) in shape and internal characters including having adont hinge, large anterior vestibulum, arcuate lists or striae on free part of inner lamella, numerous short marginal pore canals and 6 large adductor scars, the topmost being much elongated. On these bases the species is herein transferred to the genus Stenocypris Sars, 1889.  相似文献   

Correction to: Trace ambient levels of particulate mercury and its sources at a rural site near Delhi     

Anita Kumari  Umesh Kulshrestha 《Journal of Atmospheric Chemistry》2018,75(4):357-357

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A Comprehensive Review on Microalgae-Based Biorefinery as Two-Way Source of Wastewater Treatment and Bioresource Recovery     

Sumira Malik  Shristi Kishore  Jutishna Bora  Vishal Chaudhary  Anjali Kumari  Preeti Kumari  Lamha Kumar  Abhaya Bhardwaj 《洁净——土壤、空气、水》2023,51(3):2200044

In the past few years, microalgae have gained huge recognition from the scientific community due to their potential applications in the production of a broad array of bio-based products varying from biofuels to nanoparticles. Due to their elevated growth rate, high tolerance to various types of abiotic stresses, and complex metabolic capacity, microalgae can be used as promising tools for the attainment of a circular bioeconomy. Moreover, they can simply utilize nutrients from wastewater for biorefinery purposes, resulting in resource recovery coupled with wastewater treatment. However, due to their sub-optimal yields and high production costs, microalgae-based bio-products have not yet been commercialized. This review provides insights into the employment of microalgae as an efficient bioresource for the treatment of wastewater with simultaneous enactment as a biorefinery to produce biofuels, biochar, bioplastic, fertilizers, and other high-value bioproducts. Furthermore, the application of microalgal nanoparticles in wastewater treatment and prospects for genetic modification of microalgae for enhanced biorefinery capabilities have also been briefly highlighted.  相似文献   

Magnetoelastic shear wave propagation in pre-stressed anisotropic media under gravity     

Nirmala Kumari  Amares Chattopadhyay  Abhishek K. Singh  Sanjeev A. Sahu 《Acta Geophysica》2017,65(1):189-205

The present study investigates the propagation of shear wave (horizontally polarized) in two initially stressed heterogeneous anisotropic (magnetoelastic transversely isotropic) layers in the crust overlying a transversely isotropic gravitating semi-infinite medium. Heterogeneities in both the anisotropic layers are caused due to exponential variation (case-I) and linear variation (case-II) in the elastic constants with respect to the space variable pointing positively downwards. The dispersion relations have been established in closed form using Whittaker’s asymptotic expansion and were found to be in the well-agreement to the classical Love wave equations. The substantial effects of magnetoelastic coupling parameters, heterogeneity parameters, horizontal compressive initial stresses, Biot’s gravity parameter, and wave number on the phase velocity of shear waves have been computed and depicted by means of a graph. As a special case, dispersion equations have been deduced when the two layers and half-space are isotropic and homogeneous. The comparative study for both cases of heterogeneity of the layers has been performed and also depicted by means of graphical illustrations.  相似文献   

Emergence of the semi-empirical technique of strong ground motion simulation: A review     

Sandeep  A. Joshi  P. Kumari  S. Lal  Vandana  Parveen Kumar  Kamal 《Journal of the Geological Society of India》2017,89(6):719-722

High frequency ground motion simulation techniques are powerful tools for designing earthquake resistant structures in seismically active regimes. Simulation techniques also provide the synthetic strong ground motion in the regions where actual records are not available (Kumar et al. 2015).These techniques require several parameters of earthquake and other seismic information proceeding to the simulation. Practically estimation of parameters is a tough task, particularly in a region with limited information. This demands a simulation technique based on the easily estimated parameters for a new site. The purposes of this paper are to briefly review existing simulation techniques and to discuss in detail the new, simple and effective semi-empirical technique (Midorikawa 1993) of strong motion simulation.  相似文献   

Seismic interference of two nearby horizontal strip anchors in layered soil   总被引：1，自引：0，他引：1  

Priyanka Ghosh  Rajusha Kumari 《Natural Hazards》2012,63(2):789-804

In the present analysis, an attempt is made to explore the seismic response of two nearby horizontal strip anchors embedded in non-homogenous c-? soil deposit at different depths. The analysis is performed by using two-dimensional finite-element software PLAXIS 2D. Each anchor carries equal static safe-working load without violating the ultimate uplift capacity under static condition. The soil is assumed to obey the Mohr?CCoulomb failure criterion. The behavior of single isolated anchor subjected to an earthquake loading is determined first to study the interference effect between two anchors. The horizontal acceleration response obtained from the Loma Prieta Gilroy Earthquake (1989) is considered as the input excitation in the analysis. A parametric study is performed by varying the clear spacing (S) between the anchors at different embedment ratios (??). The magnitude of vertical displacement, shear stress, and shear strain developed at different locations of the failure domain is determined for different clear spacings between the anchors.  相似文献