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1.
S. Sudhakar Arvind Kumar M. L. Arrawatia S. Sengupta 《Journal of the Indian Society of Remote Sensing》1994,22(3):155-168
Remote sensing techniques have been applied to classify tour density classes within each of the forest type along with other major landuse/landcover classes in the East district, Sikkim using IRS-1A LISS II satellite data pertaining to the period of November, 1988. The shadow problem in rugged terrain and difficulty in acquiring cloud free data for different seasons pose problems to achieve considerable mapping accuracy. In the present study, the forests of the district were delineated through supervised classification techniques using maximum likelihood algorithm into five forest types as sal forests, subtropical broad-leaved forests, Himalayan wet temperate forests, Rhododendron forests and alpine forests. The alpine forests were further stratified into two categories as moist alpine scrub and dry alpine scrub. The statistical data obtained from the present study shows that 55.47 percent of the total geographical area of the East district was under forest cover. An overall accuracy of more than 85 percent in correctly delineating forest classes was achieved. 相似文献
2.
3.
Anharmonic oscillations of rotating stars have been studied by various authors in literature to explain the observed features of certain variable stars. However, there is no study available in literature that has discussed the combined effect of rotation and tidal distortions on the anharmonic oscillations of stars. In this paper, we have created a model to determine the effect of rotation and tidal distortions on the anharmonic radial oscillations associated with various polytropic models of pulsating variable stars. For this study we have used the theory of Rosseland to obtain the anharmonic pulsation equation for rotationally and tidally distorted polytropic models of pulsating variable stars. The main objective of this study is to investigate the effect of rotation and tidal distortions on the shapes of the radial velocity curves for rotationally and tidally distorted polytropic models of pulsating variable stars. The results of the present study show that the rotational effects cause more deviations in the shapes of radial velocity curves of pulsating variable stars as compared to tidal effects. 相似文献
4.
Sunspot umbral molecular lines have been used to look for the oscillatory velocities in the umbra. Power spectrum analysis showed conspicuous power for periods in the range between 448 and 310 s. The maximum peak-to-peak amplitude of the umbral oscillatory velocity component is observed to be in the order of 0.5 km s–1.Visiting Astronomer, Solar Division, Kitt Peak National ObservatoryOperated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation. 相似文献
5.
In this paper we present a method for computing the equilibrium structures and various physical parameters of a primary component
of the binary system assuming that the primary is more massive than the secondary and is rotating differentially according
to the law of the w2 = b0 + b1 × s2 + b2 × s4, w being the angular velocity of rotation of a fluid element distant s from the axis of rotation and b0, b1, b2 suitably chosen numerical constants. This method utilizes the averaging approach of Kippenhahn and Thomas (1997) and the
concept of Roche equipotentials in a manner earlier used by Mohan et al. (1997) to incorporate the effects of rotation and
tidal distortions on the equilibrium structures of certain rotationally and tidally distorted stellar models. The use of the
method has been illustrated by applying it to obtain the structures and some observable parameters of certain differentially
rotating and tidally distorted binary systems whose primary component is assumed to be a white dwarf star. 相似文献
6.
7.
Monitoring of TDS and conductivity in groundwater in the seismically active region in NW Himalayas,India 下载免费PDF全文
Arvind Kumar Surinder Singh Bikramjit Singh Bajwa Sandeep Mahajan Rajeev Kalia Sunil Dhar 《地震科学(英文版)》2010,23(3):295-299
<正>The earthquake precursors and earthquake prediction are the burning issue among the community of earth scientists and engineers. Studies of earthquake precursory phenomena since the last several decades have shown that significant geophysical and geochemical changes may occur prior to intermediate and large earthquakes (Hartmann and Levy, 2005; Yang et al, 2005; 相似文献
8.
Amit Kumar Arvind Chandra Pandey Najmul Hoda A. T. Jeyaseelan 《Journal of the Indian Society of Remote Sensing》2011,39(2):213-224
The present study analyzes the built-up expansion of Ranchi urban agglomeration over a period of about 8 decades from 1927–2005.
Satellite images and topographical maps were used to evaluate land use dynamics during these periods. Built-up growth of 473.7%
during 1927–2005 was primarily at the expense of agricultural land along with reduction of natural water bodies reflects negative
impacts of built-up expansion, which increased many folds in recent decades. The built-up growth is also analyzed with reference
to population growth, land consumption rate and land transformation. The land loss due to increasing built-up growth of Ranchi
were compared with other capital regions and cities along with population increase to provide insight into the possible scenario
of built-up expansion in Ranchi urban area. 相似文献
9.
In this paper we propose a method for computing the equilibrium structure of differentially rotating polytropic models of the stars. A general law of differential rotation of the type 2=b
0+b
1
s
2+b
2
s
4, which can account for a reasonably large variety of possible differential rotations in the stars has been used. The distortional effects have been incorporated in the structure equations up to second order of smallness in distortion parametersb
0,b
1, andb
2 using Kippenhahn and Thomas' averaging approach in conjunction with Kopal's results on Roche equipotentials in manner similar to the one earlier used by Mohan and Saxena for computing the equilibrium structure of polytropes having solid body rotation. Numerical results have been obtained for various types of differentially rotating polytropic models of stars of polytropic indices 1.5, 3, and 4. Certain differentially rotating models of the Sun which are possible with such a type of law of differential rotation, have also been computed. 相似文献
10.
The use of scrap-tire-shreds as leachate collection layer in landfills would reduce the magnitude of the current tire disposal
problem by converting a waste into a beneficial material. Laboratory studies were conducted to investigate scrap-tire-shreds
as an attractive potential alternative to conventional gravel in the drainage layer of leachate collection system by comparative
analysis of various physico-chemical parameters. Gravel and scrap-tire-shreds in combination were used as leachate collection
layer. Laboratory Test Cells consisting of different combinations of scrap-tire-shreds (size range length = 25.4 mm to 76.1 mm
and width = 5 mm) and gravel (size range 10 mm to 20 mm) beds as leachate collection layer with total bed thickness of 500 mm
were constructed. Performance study of Test Cells- 1 to 7, having different combinations of scrap-tire-shreds and gravel bed
thickness, were studied to work out the best combination. Combined beds of scrap-tire-shreds and gravel gave better results
as compared to conventional gravel or scrap- tire- shreds bed when used singly. Test Cell -3 having scrap-tire-shreds layer
(200 mm) and gravel layer (300 mm) gave the best results in terms of percentage reduction in various physico-chemical parameters
of leachate. The reduction was as high as 68.8 and 79.6% in case of Biological Oxygen Demand (BOD) and Chemical Oxygen Demand
(COD) values respectively. Further, three more laboratory Test Cells-8, 9 and 10 were constructed having scrap-tire-shreds
and gravel layer ratio same as that of Test Cell- 3 (best combination) but having scrap-tire-shreds of different widths 10 mm,
15 mm and 20 mm to find out the most suitable size. Bed of smaller size scrap-tire-shreds (5 mm) gave better results in comparison
to bigger sizes. Leachate sample after passing through combined beds of scrap-tire-shreds and gravel gave better results in
percentage reduction in various physico-chemical parameters of leachate as compared to conventional gravel or scrap-tire-shreds
bed when used singly. 相似文献