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91.
Sediment transport from mountainous to lowland areas is considered one of the most important geomorphological processes. In the present study, variations in transported sediment loads and dissolved loads have been studied over 3 years (2008–2011) for two forested catchments located in the Lesser Himalayan region of India. Seasonal and annual suspended sediment flux was strongly influenced by amounts of rainfall and streamflow. On average, 93% of annual load was produced during the monsoon, of which 62–78% occurred in only five peak events. Sediment production by the degraded forest catchment (Bansigad) was 1.9-fold (suspended sediment load) to 5.9-fold (bedload) higher than the densely forested catchment (Arnigad). The dissolved organic matter potentially influences total dissolved solids in the stream. Heavy rainfall triggers both stream discharge and landslides, which lead to higher bedload transport. Total denudation rates for Arnigad and Bansigad were estimated at 0.68 and 1.02 mm?year?1, respectively. 相似文献
92.
K. Naha A. Rai Choudhuri V. Ranjan R. Srinivasan 《Journal of Earth System Science》1995,104(3):327-347
The supracrustal enclave within the Peninsular Gneiss in the Honakere arm of the Chitradurga-Karighatta belt comprises tremolite-chlorite
schists within which occur two bands of quartzite coalescing east of Jakkanahalli(12°39′N; 76°41′E), with an amphibolite band
in the core. Very tight to isoclinal mesoscopic folds on compositional bands cut across in the hinge zones by an axial planar
schistosity, and the nearly orthogonal relation between compositional bands and this schistosity at the termination of the
tremolite-chlorite schist band near Javanahalli, points to the presence of a hinge of a large-scale, isoclinal early fold
(F1). That the map pattern, with an NNE-plunging upright antiform and a complementary synform of macroscopic scale, traces folds
'er generation (F
2),is proved by the varying attitude of both compositional bands (S0) and axial pranar schistosity (S
1), which are effectively parallel in a major part of the area. A crenulation cleavage (S
2) has developed parallel to the axial planes of theF
2 folds at places. TheF
2 folds range usually from open to rarely isoclinal style, with theF
1 andF
2 axes nearly parallel. Evidence of type 3 fold interference is also provided by the map pattern of a quartzite band in the
Borikoppalu area to the north, coupled with younging directions from current bedding andS
0
-S
1 inter-relation.
Although statistically theF
1 andF
2 linear structures have the same orientation, detailed studies of outcrops and hand specimens indicate that the two may make
as high an angle as 90°. Usually, in these instances, theF
1 lineations are unreliable around theF
2 axes, implying that theF
2 folding was by flexural slip. In zones with very tight to almost isoclinalF
2 folding, however, buckling attendant with flattening has caused a spread of theF
1 lineations almost in a plane. Initial divergence in orientation of theF
1 lineations due to extreme flattening duringF
1 folding has also resulted in a variation in the angle between theF
1 andF
2lineations in some instances. Upright later folding (F3) with nearly E-W strike of axial planes has led to warps on schistosity, plunge reversals of theF
1 andF
2 axes, and increase in the angle between theF
1 andF
2 lineations at some places. Large-scale mapping in the Borikoppalu sector, where the supposed Sargur rocks with ENE ‘trend’
abut against the N-‘trending’ rocks of the Dharwar Supergroup, shows a continuity of rock formations and structures across
the hinge of a large-scaleF
2 fold. This observation renders the notion, that there is an angular unconformity here between the rocks of the Sargur Group
and the Dharwar Supergroup, untenable. 相似文献
93.
K. H. Navalgund K. Suryanarayana Sarma Piyush Kumar Gaurav G. Nagesh M. Annadurai 《Journal of Astrophysics and Astronomy》2017,38(2):34
AstroSat is India’s first space-based observatory satellite dedicated to astronomy. It has the capability to perform multi-wavelength and simultaneous observations of cosmic bodies in a wide band of wavelengths. This paper briefly summarizes the challenges faced in the configuration of AstroSat spacecraft, accommodation and sizing of its critical subsystems, their realization and testing of payloads and the integrated satellite. 相似文献
94.
I. Wayan Budiasa I. Gusti Ngurah Santosa I. Nyoman Sunarta I. Ketut Suada I. Nyoman Rai A. A. I. Ratna Dewi V. Dias S. Moyzhes N. Shchegolkova 《Water Resources》2018,45(1):138-147
The article offers a new approach to the selection of a treatment plant, based on the optimization of biogeochemical matter flows. The existing treatment facilities of Bali are analyzed. The authors propose several process schemes for domestic wastewater treatment, depending on the technology of utilization of biogenic elements from the wastewater for agricultural production. These are based on water treatment technologies that have been in use in Moscow for more than 100 years. 相似文献
95.
A semi-analytical scheme is proposed to parametrize the Obukhov stability parameter \(\zeta \) (= \(z/L\) ; \(z\) is the height above the ground and \(L\) is the Obukhov length) in terms of the bulk Richardson number ( \(R_{iB}\) ) in unstable conditions within the framework of Monin–Obukhov similarity (MOS) theory. The scheme involves, (i) a solution of a cubic equation in \(\zeta \) whose coefficients depend on the gradient Richardson number ( \(R_{i}\) ), and (ii) a relationship between \(R_{i}\) and \(R_{iB}\) . The proposed scheme is applicable for a wide range (i) \(-5\le R_{iB}\le 0\) , (ii) \(0\le \hbox {ln}(z_{0}/z_{h})\le 29.0\) , and (iii) \(10\le z/z_{0}\le 10^{5}\) and performs relatively better than all other schemes in terms of accuracy in computation of surface-layer transfer coefficients. The absolute errors in computing the transfer coefficients do not exceed 7 %. The analysis presented here is found to be valid for different \(\gamma _{m}\) and \(\gamma _{h}\) appearing in the expressions of the similarity functions \(\varphi _{m}\) and \(\varphi _{h}\) (representing non-dimensional wind and temperature profiles), so long as the ratio of \(\gamma _{m}\) to \(\gamma _{h} \ge 1\) . The improved scheme can be easily employed in atmospheric modelling for a comprehensive range of \(R_{iB}\) and a variety of surfaces. 相似文献
96.
We report the discovery of Early Permian (late Asselian, ∼280–275 Ma) plant fossils and associated palynomorphs from a marine sedimentary sequence of the eastern Karakoram plate, in northern India. These specimens show affinities with those found in marine Lower Gondwana sediments of the Indian subcontinent. This supports the contention that during the Early Permian Period, the Karakoram plate was Peri-Gondwanan. It is suggested to have had an intermediate position between the Indian plate and the Qiangtang–Lhasa microcontinents, at a latitude of about 35° south. 相似文献
97.
Some recent developments in solar dynamo theory 总被引:1,自引:0,他引:1
Arnab Rai Choudhuri 《Journal of Astrophysics and Astronomy》2006,27(2-3):79-85
We discuss the current status of solar dynamo theory and describe the dynamo model developed by our group. The toroidal magnetic
field is generated in the tachocline by the strong differential rotation and rises to the solar surface due to magnetic buoyancy
to create active regions. The decay of these active regions at the surface gives rise to the poloidal magnetic field by the
Babcock-Leighton mechanism. This poloidal field is advected by the meridional circulation first to high latitudes and then
down below to the tachocline. Dynamo models based on these ideas match different aspects of observational data reasonably
well. 相似文献
98.
Srivastava Piyush Sharan Maithili Kumar Manoj 《Theoretical and Applied Climatology》2020,139(3):1057-1077
Theoretical and Applied Climatology - The present study utilizes the turbulence observations over an Indian region, Ranchi, to study the diurnal and seasonal characteristics of mean and turbulent... 相似文献
99.
Sukanta Goswami Sangeeta Bhagat Syed Zakaulla Suresh Kumar A. K. Rai 《Journal of the Geological Society of India》2017,89(2):145-154
Dolostone of Vempalle Formation near Tummalapalle hosts large uranium deposit (>100,000 tonnes with an average grade of 0.045%U3O8). It is a unique type of uranium deposit because carbonate formations have been considered to be among the least uraniferous of all the rocks of the Earth’s crust due to mobility of uranium in aqueous fluid in the presence of carbonate and bicarbonate ions. Vempalle dolostone hosts syn-sedimentary uranium mineralization in the form of discrete uranium phases (pitchblende and coffinite) associated with collophane, and adsorbed uranium in organic matter. The organic matter has played dual role of concentrating uranium from solution and also chemically reducing it to pitchhblende and coffinite. 相似文献
100.
By introducing an asymmetry between the two hemispheres, we study whether the solar dynamo solutions in the two hemispheres
remain coupled with each other. Our calculations are based on the solar dynamo code SURYA, which incorporates the helioseismically-determined
solar-rotation profile, a Babcock–Leighton α effect concentrated near the surface, and a meridional circulation. When the magnetic coupling between the hemispheres is
enhanced by either increasing the diffusion or introducing an α effect distributed throughout the convection zone, we find that the solutions in the two hemispheres evolve together with
a single period even when we make the meridional circulation or the α effect different in the two hemispheres. On the other hand, when the hemispheric coupling is weaker for other values of parameters,
an asymmetry between the hemispheres can make solutions in the two hemispheres evolve independently with different periods. 相似文献