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31.
Rabindra Nath Das 《Astrophysics and Space Science》1978,58(2):419-425
The basic integro-differential equation is subjected to a one-sided finite Laplace transform to obtain linear integral equations of angular distribution of bounding faces. These linear integral equations have been transformed into linear singular integral equations which have been solved exactly to get the emergent distributions from the bounding faces by the theory of linear singular operators. Some solutions of linear singular integral equations have also been derived for future use in radiative transfer problems. 相似文献
32.
Analytical study is performed to examine heat and mass transfer characteristics of natural convection flow of an incompressible, rarefied visco-elastic fluid past an infinite vertical porous plate with constant suction in the presence of transverse magnetic field under combined buoyancy force effects of thermal and mass diffusion. The effects of various parameters on mean velocity and mean skin-friction are shown graphically followed by a comparative study of Newtonian and non-Newtonian (visco-elastic). rarefied states. 相似文献
33.
Rabindra Nath Das 《Astrophysics and Space Science》1979,62(1):149-157
We consider the problem of determining the emergent intensity from the bounding face of a semi-infinite atmosphere having conservative scattering and the intensity at any optical depth by use of the Laplace transform in combination with the Wiener-Hopf technique when the incoming intensity at the bounding face of the atmosphere is known. The solution is exact. 相似文献
34.
Rabindra Nath Das 《Astrophysics and Space Science》1980,67(2):335-342
The key equation which commonly appears for radiative transfer in a finite stellar atmosphere having ground reflection according to Lambert's law is considered in this paper. The exact solution of this equation is obtained for surface quantities in terms of theX-Y equations of Chandrasekhar by the method of Laplace transform and linear singular operators. This exact method is widely applicable for obtaining the solution for surface quantities in a finite atmosphere. 相似文献
35.
Namrata Das Saroj Sundar Baral Parth Sarathi Mahapatra Trupti Das Gautam Roy Chaudhury Surendra Nath Das 《Theoretical and Applied Climatology》2012,110(1-2):55-63
Precipitation samples collected during 2005–2009 from a rural forest station of Bhubaneswar were analyzed for their chemical composition. The samples were collected through a wet-only (WO) collector and two bulk (B1 and B2) collectors. The ions were evenly balanced indicating good data quality. The overall pH of rainwater was slightly acidic and ~47% of all rain events during the period were acidic (pH?<?5.6). Multilinear regression analysis showed relation between the free acidity (H+) and other components in rainwater. Enrichment factors (EF) of the major components with respect to their sources such as marine and crustal were calculated. Maximum EF was observed for NO 3 ? for both marine and crustal sources for all the three collectors. Source apportionments were also carried for the ions. Trend analysis showed continuous increase in most of the ions over years during the study period driven by anthropogenic emissions. Statistical/factorial analysis established correlation among different ions. 相似文献
36.
Heavy mineral analysis has been carried out in the Barakar Formation of the Talchir Gondwana Bbasin, Orissa. The characteristic
heavy minerals are garnet, zircon, tourmaline, rutile, biotite, chlorite, pyroxenes, hornblende, staurolite, sillimanite,
apatite, epidote, sphene, spinel and siderite including opaques and leucoxene. These heavy minerals are divisible into four
groups on the basis of principal component analysis and suggest derivation of Barakar sediments from pegmatite, acid and basic
igneous as well as low- and high-rank metamorphic rocks lying to the south of the Talchir Gondwana Basin. Though the heavy
mineral suites of all the sandstone samples are by and large similar, differences have been noticed in the frequencies of
many heavy minerals in vertical succession. Cyclic nature and vertical fluctuation of heavy mineral frequencies can be ascribed
to variation of the relief of the source area, sudden release of some of the minerals in the source region and/or existence
of favourable geochemical condition to escape partial dissolution. 相似文献
37.
Asha Nath G. K. Manohar K. K. Dani P. C. S. Devara 《Journal of Earth System Science》2009,118(5):467-481
Monthly variations of lightning activity over typical land and oceanic regions of India were examined using satellite data
(OTD) for a 5-year period (1995–1999). It is noted that the nature of variation between surface air maximum temperature (T
max), thunderstorm days (Thn), and lightning flash count over ER and WR showed remarkable correspondence and sensitivity with each other on monthly time
scale. As we move out of winter season and enter the monsoon season, via pre-monsoon season, the WR undergoes cooling relative
to the ER in the range 0.1–1.2°C. As a result, WR experiences reduction of thunder days and lowering in flash count. This
decrease in T
max, Thn, and flash count over WR may also be associated with relatively small values of T
θw
and CAPE in comparison with similar values over ER during the monsoon season. Our observation of associated reduction in
Thn and lightning count per 1°C cooling in surface air maximum temperature suggests reduction of ∼3.5 thunderstorms per station
and 73 flashes. Comparison of lightning flashes between pairs of coastal, oceanic, arid-zone, hilly, and island stations reveals
distinct relationship between climate regime and intensity of lightning activity. We may conclude the results of this study
by saying that the overhead lightning activity is a clear reflection of the status of the underlying ground-earth properties.
A close and continuous monitoring of lightning activity may be considered as a need of present day scientific studies. 相似文献
38.
39.
Abstract As the quest for deep-sea mineral resources is gaining momentum, environment and ocean mining have become important aspects of study. Because many of these deposits occur in international waters, the concern for environmental conservation in view of the effects of deep-sea mining is resulting in these effects being studied in different oceans, and efforts to develop regulations governing this exploitation are also underway at national and international levels. The impact assessment of deep-sea mining needs to encompass a variety of subjects, including environmental, socioeconomic, technological, and legal aspects. At the same time, effects of in situ environmental conditions on mining activities also need to be considered for effecient performance by the mining system. Differences in the degree of impact have been noticed during the mining simulation experiments by different investigating agencies. Therefore, interparameter comparisons, standardization of methods, and improvement in mining design are important considerations for proper utilization of resources, conservation of environment, and cost efficiency of the mining operations. 相似文献
40.
Sangeeta Sharma Jogendra Nath Sarma 《Journal of the Indian Society of Remote Sensing》2013,41(4):895-904
An analysis of the drainage network of a part of Sivasagar district, Assam, India, is undertaken to reveal the role of neotectonic activity of the area. A number of fluvial geomorphic anomalies have been identified in the area. A prominent annular drainage anomaly is displayed by the major rivers—the Dikhu, Jhanzi, Namdang, Dorika and Disang, whose courses are carved in response to the ongoing tectonic deformation in the area. This study reveals that the development of topography and drainage system of the study area have been influenced by active subsurface geological structures. Formation of paleochannels, compressed meanders, reticulate streams, swamps, sagging of grounds, stream alignments, lineaments, knick points and abandonment of rivers as well as development of smaller drainage anomalies also substantiate the active nature of the subsurface structures. 相似文献