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Prakash K. Siddharth Prabhu N. Sridharan A. 《Geotechnical and Geological Engineering》2021,39(6):4669-4676
Geotechnical and Geological Engineering - Montmorillonitic soils pose problems in the field as they are capable of exhibiting appreciable swelling when come in contact with water. In this context,... 相似文献
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Glacierised basins are significant sources of sediments generated by glacial retreat. Estimation of suspended sediment transfer from glacierised basins is very important in reservoir planning for hydropower projects in Himalaya. The present study indicates that storage and release of sediment in proglacial streams may categorise the pattern of suspended sediment transfer from these basins. Assessment of suspended sediment concentration (SSC), suspended sediment load (SSL) and yield has been undertaken for Dunagiri Glacier basin located in Garhwal Himalaya (30o33'20”N, 79o53'36”E), and its results are compared with the Gangotri and Dokriani glaciers sharing close proximity. Out of the total drainage basin area, about 14.3 % of the area is glacierised. Data were collected for five ablation seasons (1984–1989, barring 1986). The mean daily SSCs for July, August and September were 333.9, 286.0 and 147.15 mg/l, respectively, indicating highest concentration of mean daily suspended sediment in July followed by August. SSL trends were estimated to be 93.0, 57.0 and 21.3 tonnes. About 59% of the total SSL of the melt period was transported during the months of August and September. Sediment yield for the study basin was computed to be 296.3 t km?2 yr ?1. It is observed that the cumulative proportion of SSC precedes the discharge throughout the melt season except in the year 1987. Release of SSL in terms of total load is less in the early part of melt season than in the later stage as compared to that of discharge. Diurnal variations in SSC reach their maximum at 2400 h, and therefore, SSC was found to be high during night (2000–0400 h). There was a good relationship between SSC and SSL with discharge for the ablation seasons (1988 and 1989). Mean monthly SSC and mean monthly SSL provide a good exponentional relationship with mean monthly temperature. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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S. P. Prizomwala S. B. Shukla Nilesh Bhatt 《Journal of the Geological Society of India》2012,79(6):557-562
Indus is one of the major sources of sediments to the Gulf of Kachchh. Yet only its <63 micron fraction is studied in detail
with regards to the offshore current dynamics. Hence here we present our study on characteristic signature of the Indus sediment
load (i.e. mica minerals) in >63 micron size fraction along the coast of Gulf of Kachchh. The spatial distribution of mica
minerals along the Gulf of Kachchh coast was studied which showed in general decreasing trend as we move along the northern
and southern coast of the Gulf of Kachchh but, an increase in amount near the southern mouth at Okha. The study shows that
the earlier proposed tidal barrier is ineffective in restricting movement of mica across the mouth of the gulf due to its
characteristic transport mechanism. Also the presence of mudflats along the gulf of Kachchh coast plays a vital role as sediment
receptors in the active sediment transport processes and mica minerals prove to be a promising simple tracer in studying the
Indus born sediments in the region. 相似文献
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Kumar Siddharth Arora Anika Chattopadhyay R. Hazra Anupam Rao Suryachandra A. Goswami B. N. 《Climate Dynamics》2017,48(3-4):999-1015
Climate Dynamics - Modification of the vertical structure of non-adiabatic heating by significant abundance of the stratiform rain in the tropics has been known to influence the large-scale... 相似文献
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The paper presents a computationally efficient algorithm to integrate a probabilistic, non-Gaussian parameter estimation approach for nonlinear finite element models with the performance-based earthquake engineering (PBEE) framework for accurate performance evaluations of instrumented civil infrastructures. The algorithm first utilizes a minimum variance framework to fuse predictions from a numerical model of a civil infrastructure with its measured behavior during a past earthquake to update the parameters of the numerical model that is, then, used for performance prediction of the civil infrastructure during future earthquakes. A nonproduct quadrature rule, based on the conjugate unscented transformation, forms an enabling tool to drive the computationally efficient model prediction, model-data fusion, and performance evaluation. The algorithm is illustrated and validated on Meloland Road overpass, a heavily instrumented highway bridge in El Centro, CA, which experienced three moderate earthquake events in the past. The benefits of integrating measurement data into the PBEE framework are highlighted by comparing damage fragilities of and annual probabilities of damages to the bridge estimated using the presented algorithm with that estimated using the conventional PBEE approach. 相似文献
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K. S. Dwarakanath Siddharth Malu Ruta Kale 《Journal of Astrophysics and Astronomy》2011,32(4):529-532
We have discovered a giant radio halo in the massive merging cluster MACSJ0417.5-1154. This cluster, at a redshift of 0.443,
is one of the most X-ray luminous galaxy cluster in the MAssive Cluster Survey (MACS) with an X-ray luminosity in the 0.1–2.4
keV band of 2.9×1045 erg s − 1. Recent observations from GMRT at 230 and 610 MHz have revealed a radio halo of ∼ 1.2 × 0.3 Mpc2 in extent. This halo is elongated along the North-West, similar to the morphology of the X-ray emission from Chandra. The
1400 MHz radio luminosity (L
r) of the halo is ∼2 × 1025 W Hz − 1, in good agreement with the value expected from the L
x − L
r correlation for cluster halos. 相似文献
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Prizomwala S. P. Gandhi Drasti Ukey Vishal M. Bhatt Nilesh Rastogi B. K. 《Natural Hazards》2015,75(2):1187-1203
Natural Hazards - The coastal segment of Diu Island from west coast of India has been studied for its boulder deposits. The dimensions, morphology and characteristics of these boulders were studied... 相似文献
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Ruta Kale K. S. Dwarakanath Dharam Vir Lal Joydeep Bagchi Surajit Paul Siddharth Malu Abhirup Datta Viral Parekh Prateek Sharma Mamta Pandey-Pommier 《Journal of Astrophysics and Astronomy》2016,37(4):31
The intra-cluster and inter-galactic media that pervade the large scale structure of the Universe are known to be magnetized at sub-micro Gauss to micro Gauss levels and to contain cosmic rays. The acceleration of cosmic rays and their evolution along with that of magnetic fields in these media is still not well understood. Diffuse radio sources of synchrotron origin associated with the Intra-Cluster Medium (ICM) such as radio halos, relics and mini-halos are direct probes of the underlying mechanisms of cosmic ray acceleration. Observations with radio telescopes such as the Giant Metrewave Radio Telescope, the Very Large Array and the Westerbork Synthesis Radio Telescope have led to the discoveries of about 80 such sources and allowed detailed studies in the frequency range 0.15–1.4 GHz of a few. These studies have revealed scaling relations between the thermal and non-thermal properties of clusters and favour the role of shocks in the formation of radio relics and of turbulent re-acceleration in the formation of radio halos and mini-halos. The radio halos are known to occur in merging clusters and mini-halos are detected in about half of the cool-core clusters. Due to the limitations of current radio telescopes, low mass galaxy clusters and galaxy groups remain unexplored as they are expected to contain much weaker radio sources. Distinguishing between the primary and the secondary models of cosmic ray acceleration mechanisms requires spectral measurements over a wide range of radio frequencies and with high sensitivity. Simulations have also predicted weak diffuse radio sources associated with filaments connecting galaxy clusters. The Square Kilometre Array (SKA) is a next generation radio telescope that will operate in the frequency range of 0.05–20 GHz with unprecedented sensitivities and resolutions. The expected detection limits of SKA will reveal a few hundred to thousand new radio halos, relics and mini-halos providing the first large and comprehensive samples for their study. The wide frequency coverage along with sensitivity to extended structures will be able to constrain the cosmic ray acceleration mechanisms. The higher frequency (>5 GHz) observations will be able to use the Sunyaev–Zel’dovich effect to probe the ICM pressure in addition to tracers such as lobes of head–tail radio sources. The SKA also opens prospects to detect the ‘off-state’ or the lowest level of radio emission from the ICM predicted by the hadronic models and the turbulent re-acceleration models. 相似文献