RESISTIVITY PROFILES OVER SOME DYKES OF DHANBAD*     

J. SINGH  B. P. JHA 《Geophysical Prospecting》1972,20(1):130-141

A number of resistivity profiles over dolerite and metadolerite dykes have been taken using Wenner and Schlumberger configurations around Dhanbad in order to find the potential of these for water accumulation. These dykes give rise to both resistivity highs and lows as compared to the background. The results are discussed in the light of known theories. Some suitable sites for water accumulation have been delineated.  相似文献   

CHANGES IN CHANNEL PATTERN OF RIVER GANGA BETWEEN MUSTAFABAD AND RAJMAHAL, GANGETIC PLAINS SINCE 18TH CENTURY   总被引：1，自引：0，他引：1  

Prabhata K. SWAMEE  Barham PARKASH  Jayaprakash V THOMAS  Satvindar SINGH 《国际泥沙研究》2003,18(3)

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RESISTIVITY SOUNDING ON A HORIZONTALLY STRATIFIED MULTI-LAYERED EARTH*     

S.S. RAGHUWANSHI  BIJENDRA SINGH 《Geophysical Prospecting》1986,34(3):409-423

The electrical potential due to a point source of current placed on the ground surface is studied for a multi-layered earth consisting of homogeneous overburden of constant conductivity over a stack of transition layers where conductivity varies with depth according to power and exponential laws in even and odd layers, respectively. The general recursion relations are derived and are used to obtain expressions for the apparent resistivities for Schlumberger and Wenner electrode arrays. Their asymptotic behavior has been studied. The solutions for some particular cases are given: (i) odd layers with conductivities exponentially varying with depth while all even layers (and the first) have constant conductivities; (ii) even layer conductivities varying as a power law while odd number layers are of constant conductivity; and (iii) any two successive layers as transition layers and all others having constant conductivities. Further it is shown that Patella's theory is a particular case of the present study. It is concluded, therefore, that the present treatment is more general as all earlier models consisting of trasition layers can be derived from this study.  相似文献   

Trend in Observed and Projected Maximum and Minimum Temperature over N-W Himalayan Basin     

Dharmaveer SINGH  Sanjay K JAIN  Rajan Dev GUPTA 《山地科学学报》2015,(2):417-433

Recently, study in past trends of climate variables gained significant consideration because of its contribution in adaptions and mitigation strategies for potential future changes in climate, primarily in the area of water resource management. Future interannual and inter-seasonal variations in maximum and minimum temperature may bring significant changes in hydrological systems and affect regional water resources. The present study has been performed to observe past(1970-2010) as well as future(2011-2100)spatial and temporal variability in temperature(maximum and minimum) over selected stations of Sutlej basin located in North-Western Himalayan region in India. The generation of future time series of temperature data at different stations is done using statistical downscaling technique. The nonparametric test methods, modified Mann-Kendall test and Cumulative Sum chart are used for detecting monotonic trend and sequential shift in time series of maximum and minimum temperature. Sen’s slope estimator test is used to detect the magnitude of change over a period of time on annual and seasonal basis. The cooling experienced in annual TMax and TMin at Kasol in past(1970-2010) would be replaced by warming in future as increasing trends are detected in TMax during 2020 s and 2050 s and in TMin during 2020 s, 2050 s and 2080 s under A1 B and A2 scenarios. Similar results of warming are also predicted at Sunnifor annual TMin in future under both scenarios which witnessed cooling during 1970-2010. The rise in TMin at Rampur is predicted to be continued in future as increasing trends are obtained under both the scenarios. Seasonal trend analysis reveals large variability in trends of TMax and TMin over these stations for the future periods.  相似文献   

High grade metamorphism in the Bundelkhand massif and its implications on Mesoarchean crustal evolution in central India     

SINGH  S P  DWIVEDI  S B 《Journal of Earth System Science》2015,124(1):197-211

Journal of Earth System Science - The Bundelkhand Gneissic Complex (BnGC) in the central part of the Bundelkhand massif preserves a supracrustal unit which includes pelitic...  相似文献   

ACTIVE AND SEMI-ACTIVE CONTROL OF STRUCTURES UNDER SEISMIC EXCITATION     

M. P. SINGH  E. E. MATHEU  L. E. SUAREZ 《地震工程与结构动力学》1997,26(2):193-213

Considerable effort has been devoted to develop passive and active methods for reducing structural response under seismic excitations. Passive control approaches have already found application in practice. Active control methods, on the other hand, are being vigorously examined for application to civil structures. This paper investigates the application of active and semi-active control schemes to structures subjected to seismic excitations, and it focuses on the use of the sliding-mode control approach for the development of the control algorithms. The possibility of control redundancy with respect to the number of sliding constraints is taken into account in the controller design. Several sets of numerical results are obtained for a realistic 10-storey shear building, subjected to earthquake-induced ground motions and controlled by active or semi-active control schemes. It is observed that both active and semi-active control schemes can be used to reduce the dynamic response. Active control performs very effectively in reducing the structural response, but the required control force values can be quite large to limit its practical application in the case of large and massive buildings. Active regulation of linear viscous dampers was found unnecessary for this type of structural system, as it did not induce any significantly more reduction in the response than the dampers acting passively. On the other hand, it is shown that active regulation of stiffness can be used with advantage to reduce the response. © 1997 by John Wiley & Sons, Ltd.  相似文献   

Sensitivity of mass transfer-based evaporation equations to errors in daily and monthly input data     

V. P. SINGH  C.-Y. XU 《水文研究》1997,11(11):1465-1473

The influence of data errors on the performance of mass transfer-based evaporation equations was investigated for both monthly and daily data from a climatological station in the State of Vaud in Switzerland. Evaporation estimates were found to be particularly sensitive to vapour pressure gradient, less sensitive to wind speed and most insensitive to temperature. A quantitative analysis showed that: (1) systematic errors in vapour pressure data influenced evaporation estimates inversely to more or less the same magnitude for both monthly and daily cases; (2) systematic errors in wind speed and temperature data influenced evaporation estimates inversely to the magnitude of about a half and a quarter of the magnitude of the influence of vapour pressure errors, respectively; and (3) evaporation estimates were much more sensitive to random errors in the case of monthly data than daily data. © 1997 John Wiley & Sons, Ltd.  相似文献   

Spectral characterization of soil and coal contamination on snow reflectance using hyperspectral analysis     

S K SINGH  A V KULKARNI  B S CHAUDHARY 《Journal of Earth System Science》2011,120(2):321-328

Snow is a highly reflecting object found naturally on the Earth and its albedo is highly influenced by the amount and type of contamination. In the present study, two major types of contaminants (soil and coal) have been used to understand their effects on snow reflectance in the Himalayan region. These contaminants were used in two categories quantitatively – addition in large quantity and addition in small quantity. Snow reflectance data were collected between 350 and 2500 nm spectral ranges and binned at 10 nm interval by averaging. The experiment was designed to gather the field information in controlled conditions, and radiometric observations were collected. First derivative, band absorption depth, asymmetry, percentage change in reflectance and albedo in optical region were selected to identify and discriminate the type of contamination. Band absorption depth has shown a subtle increasing pattern for soil contamination, however, it was significant for small amounts of coal contamination. The absorption peak asymmetry was not significant for soil contamination but showed a nature towards left asymmetry for coal. The width of absorption feature at 1025 nm was not significant for both the contaminations. The percentage change in reflectance was quite high for small amount of coal contamination rather than soil contamination, however, a shift of peak was observed in soil-contaminated snow which was not present in coal contamination. The albedo drops exponentially for coal contamination rather than soil contamination.  相似文献   

Numerical study of mechanism of fold formation in a laminated rock     

P K SAINI  T KUMAR  T N SINGH  N SINGH  V K KESHRI 《Journal of Earth System Science》2011,120(6):965-978

A set of large deformation experiments are presented to simulate folding pattern at various energy states during formation. In order to numerically simulate this phenomenon, a rectangular layer of shale is generated and compressed at various strain rates. The results reveal the variation in distribution of stress along the length of the bed. The stress distribution during elastic behaviour of shale bed at low compression rate and the change in stress distribution leading to rupture at high compression rates is discussed. Wavelength, limb length, bulk shortening, stress distribution, displacement of particles along the length of the bed is considered for comparative study of the fold pattern generated at various compression rates. The nature and position of crack generated during the formation of fold is also explained. After rupture in shale bed, the generation of fault and stress distribution in limbs of fold sliding over one another is also described.  相似文献   

Well storage effect during pumping tests in an aquifer of low permeability     

V. S. SINGH 《水文科学杂志》2013,58(4):589-594

Abstract

Well storage effect is generally considered while interpreting pumping test data from large diameter wells. However, in an aquifer of low permeability, the well storage is found to be significant during pumping tests conducted on bore wells. The interpretation of such data gives ambiguous results unless well storage effect is taken into account. A field example is presented to illustrate the difficulty in interpretation of the pumping test data. In order to take into account the well storage effect, a finite difference approach of interpreting pumping test data is suggested.  相似文献