Heavy metal distribution and environmental status of Doon Valley soils, Outer Himalaya, India   总被引：1，自引：0，他引：1  

K. K. Purohit  P. K. Mukherjee  P. P. Khanna  N. K. Saini  M. S. Rathi 《Environmental Geology》2001,40(6):716-724

 Doon Valley is surrounded by two major river systems (Ganga and Yamuna) on either side, with a water divide passing nearly across the centre of the valley, and is sandwiched between two mountain ranges in the fragile ecological systems of the Himalayan foothills. In total 398 soil samples were collected from the valley in a grid pattern (∼1 sample per 2 km²) and investigated for their heavy metal (Cr, Cu, Ni, Pb and Zn) abundances that are environmentally sensitive. Comparison of the heavy metal abundances with the contamination threshold values (CTV) revealed that most of these elemental abundances in Doon Valley soils fall well within the range of the uncontaminated to slightly contaminated category. In the case of Cr and Ni, a sizeable number of samples exceeded the CTV (250 and 100 mg kg^–1 respectively) with an overall background value of 109 and 52 mg kg^–1 respectively. Sites of high Cr and Ni mostly occur in the Ganga Catchment (GC) sector that includes even relatively undisturbed forestland. The source of this contamination is attributed to geological factors which indicate contribution from the mafic volcanics of the Lesser Himalaya. This is also consistent with the distribution pattern of Mn and Fe, though their abundance levels are not alarming. The background concentration of Pb is low (22 mg kg^–1) in Doon Valley soils; however, signs of gradual Pb contamination are palpable in and around the centre of the Dehra Dun city and along the highways. Aluminium normalized heavy metal ratios were found to exhibit narrow variability in the case of Cu, Ni and Cr and had good correlation with Al, indicating their affinity and association with the clay minerals. On the other hand, Pb and Zn seem to be associated with non-silicate sources. Received: 7 January 2000 · Accepted: 30 July 2000  相似文献   

On the disturbances in an inhomogenous medium due to transient forces and twists on the surface of a burried spherical source     

Jyotirmay Mukherjee 《Pure and Applied Geophysics》1970,79(1):66-72

Summary In this paper the displacements and stresses are obtained due to two types of forces: (i) transient normal forces, (ii) transient twists on the surface of a burried spherical source. The material is assumed to be inhomogeneous and spherically aeolotropic. Laplace transform technique has been used here.  相似文献   

Approximate analysis of natural vibrations of coupled shear walls     

A. Coull  P. R. Mukherjee 《地震工程与结构动力学》1973,2(2):171-183

The continuous connection technique is used to analyse the free vibrations of a system of coupled shear walls. The dynamic equation is expressed in integro-differential form, and the natural modes and frequencies are determined by the Galerkin method. Theoretical results are compared with published experimental data.  相似文献   

Wavelet-based generation of spectrum-compatible time-histories   总被引：6，自引：0，他引：6  

Sushovan Mukherjee  Vinay K. Gupta   《Soil Dynamics and Earthquake Engineering》2002,22(9-12):799-804

This paper deals with the well-known problem of generating spectrum-compatible synthetic accelerograms for the linear and non-linear time-history analyses of structural systems. A wavelet-based procedure has been used to decompose a recorded accelerogram into a desired number of time-histories with non-overlapping frequency contents, and then each of the time-histories has been suitably scaled for matching of the response spectrum of the revised accelerogram with a specified design spectrum. The key idea behind this iterative procedure is to modify a recorded accelerogram such that the temporal variations in its frequency content are retained in the synthesized accelerogram. The proposed procedure has been illustrated by modifying five recorded accelerograms of widely different characteristics such that those are compatible with the same USNRC design spectrum.  相似文献   

Model selection in cosmology     

Andrew Liddle  Pia Mukherjee  David Parkinson 《Astronomy& Geophysics》2006,47(4):4.30-4.33

Andrew Liddle, Pia Mukherjee and David Parkinson discuss the new precision available to cosmological modellers.  相似文献   

Experimental and simulation studies on the role of fluid velocity during particle separation in a liquid–solid fluidized bed     

A.K. Mukherjee  B.K. Mishra 《International Journal of Mineral Processing》2007

The fluidization technique has been in use for particulate material processing operations for many years. It has been widely believed that the ratio of size and density of the particulate components controls the separation efficiency. In this paper, it is demonstrated that fluid velocity during fluidization could assume an overriding significance when an improvement in separation efficiency is required. This was at first experimentally established by analyzing simpler particulate systems, and later a simulation scheme was adopted to study a wider range of particulate systems. The numerical scheme known as the discrete element method (DEM), that incorporates both the solid- and hydro-dynamic components of the interactive forces, served as an important tool in understanding the separation behavior of binary particulate systems in fluidized beds. It has been established that mere fluidization does not necessarily guarantee an optimal separation, especially when the particles differ widely in density and size.  相似文献   

GIS use by an urban local body as part of e-governance in India     

Falguni Mukherjee 《制图学和地理信息科学》2018,45(6):556-569

Government organizations in the developing world have been at the forefront of ongoing reforms that have prompted their use of GIS and other information and communication technologies for urban governance. However, there have been very few examinations of GIS spatial knowledge construction in a non-Western context. Particularly, very little is known about the growing and varying use of GIS and spatial information by urban local bodies in India in the midst of India’s changing urban governance culture. This article presents an in-depth examination of Surat Municipal Corporation (SMC), one of India’s leading urban local bodies as the corporation implements e-governance strategies including the use of GIS and spatial information. Drawing from Critical GIS literature and GIS implementation and diffusion literature, this article uses an integrated approach to examine SMC’s GIS spatial knowledge construction. The article demonstrates that in the case of SMC, GIS knowledge construction is not only shaped by SMC’s proactive role in positioning itself with the national government’s priorities and agendas, but also by the presence of powerful actors who play an instrumental role in introducing change and innovation. This article is part of a larger project that aims to investigate the process of GIS spatial knowledge construction situated in contemporary India.  相似文献   

Extraction of impervious features from spectral indices using artificial neural network     

Nilanchal?PatelEmail author  Rohit?Mukherjee 《Arabian Journal of Geosciences》2015,8(6):3729-3741

An urban area comprises a complex mix of diverse land cover types and materials. Urban ecology and environment is significantly influenced by the proportion of impervious cover that is increasing considerably with time due to the continuous influx of people into urban areas. Therefore, it is of vital importance to determine the spatiotemporal pattern and magnitude of urbanization. In the present study, we have employed a supervised backpropagation neural network in order to extract the impervious features using five spectral indices, such as one vegetation index—Soil-Adjusted Vegetation Index (SAVI), one water index—Modified Normalized Water Index (MNDWI), and three urban indices—Normalized Difference Built-up Index (NDBI), Built-up Index (BUI), and Index-Based Built-up Index (IBI). The study has been performed using Landsat Thematic Mapper data of November, 2011, of the rapidly urbanizing city of Ranchi, capital of Jharkhand state, India. Using different combinations of these spectral indices while keeping SAVI and MNDWI constant, seven composite images were built, and from each of these composites, impervious features were classified and its accuracy assessed with reference to high-resolution images provided by Microsoft Bing Imagery and adequate ground truthing. It was observed that along with SAVI and MNDWI, whenever IBI was used in any combination, it decreased the classification efficiency. On the other hand, NDBI and BUI, individually or when used together, discriminated the impervious features from the others with high accuracy with the combination of SAVI, MNDWI, and BUI achieving the highest accuracy of 90.14 %.  相似文献   

Summer monsoon rainfall trends in the Indian Himalayan region   总被引：1，自引：0，他引：1  

Sandipan Mukherjee  Rajesh Joshi  Ram C. Prasad  Subhash C. R. Vishvakarma  Kireet Kumar 《Theoretical and Applied Climatology》2015,121(3-4):789-802

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Erratum to: Summer monsoon rainfall trends in the Indian Himalayan region     

Sandipan Mukherjee  Rajesh Joshi  Ram C. Prasad  Subhash C. R. Vishvakarma  Kireet Kumar 《Theoretical and Applied Climatology》2015,121(3-4):803-805

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