Characteristics of severe thunderstorms studied with the aid of VLF atmospherics over North–East India     

A GUHA  TRISANU BANIK  BARIN KUMAR DE  RAKESH ROY  ABHIJIT CHOUDHURY 《Journal of Earth System Science》2013,122(4):1013-1021

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Investigating the Tsunamigenic Potential of Earthquakes from Analysis of the Informational and Multifractal Properties of Seismograms     

Luciano Telesca  Ashutosh Chamoli  Michele Lovallo  Tony Alfredo Stabile 《Pure and Applied Geophysics》2015,172(7):1933-1943

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Effect of different wall roughness on the frictional behavior of rock joints     

Debanjan Guha Roy  Ashutosh Tripathy  T. N. Singh 《Journal of the Geological Society of India》2017,89(3):303-306

Rock discontinuities play a crucial and critical role on the deformational and failure behavior of the rock mass. In most investigations, both the surfaces of the rock joints are considered to have same roughness. But, in nature, the walls of a fresh joint is only expected to be complimentary and to have same roughness. Weathered and water percolating rock joint is most likely to develop different surface roughness on the two opposite walls. So, the shear strength and frictional response behavior derived from the single joint roughness coefficient (JRC) assumption cannot be used in such a condition. To address this shortcoming, we have prepared sandstone blocks with different surface roughness and conducted experiments in a tribometer. The static friction, shear stiffness and coefficient-of-friction of the joint surfaces were calculated and their changes with increasing normal load were noted. One of the major findings of this paper is that, shear strength of the joints may not have a direct correlation with the increasing JRC value of the individual joint walls. Hence, some of the joint walls having higher cumulative JRCs were found to show lower shear strength than those with lowers roughness. This is because, the opposing walls of such joints are not anymore complementary and the frictional resistance is completely controlled by the height and contact area of the asperites.  相似文献   

A NUMERICAL METHOD TO COMPUTE THE RESISTIVITY TRANSFORM FROM WENNER SOUNDING DATA*     

RAKESH KUMAR  M. V. RAMANAIAH CHOWDARY 《Geophysical Prospecting》1982,30(6):898-909

A numerical technique to compute the resistivity transform directly from the observed Wenner sounding data has been developed. In principle, the procedure is based on a decomposition method and consists of two steps: the first step determines a function that approximates the apparent resistivity data and the second step transforms this function into the corresponding kernel by an analytical operation. The proposed method is tested on some theoretical master curves. A high degree of precision is achieved with very little computer time. The applicability is shown on two field examples.  相似文献   

Assessment and monitoring of estuarine mangrove forests of Goa using satellite remote sensing     

I. J. Singh  S. K. Singh  S. P. S. Kushwaha  Subhash Ashutosh  R. K. Singh 《Journal of the Indian Society of Remote Sensing》2004,32(2):167-174

The present study highlights the application of satellite remote sensing in the assessment and monitoring of the mangrove forests along the coastline in Goa state of India. Based on onscreen visual interpretation techniques various land use and land cover classes have been mapped and classified. An attempt has been made to analyse changes in the mangrove forest cover from 1994 to 2001 using IRS-1B LISS-II and IRS-1D LISS-III data. An increase in the mangrove vegetation in the important estuaries has been found during 1994 and 2001. During this period, the mangrove forest increased by 44.90 per cent as a result of increased protection and consequent regeneration. Plantation of mangrove species has been raised in 876 ha (1985 to 1997) by the State Forest Department¨  相似文献   

Oldest Asian Record of Snapping Shrimps (Malacostraca: Alpheidae) from the Kutch Basin, Western India and Associated Biota: Biostratigraphic, Paleoenvironmental and Paleoecological Significance     

Vivesh V. KAPUR  Kamlesh KUMAR  Pranav J. PANDYA  Amit K. GHOSH  Arindam CHAKRABORTY  Anupam SHARMA  Gaurav CHAUHAN  M. G. THAKKAR 《《地质学报》英文版》2022,96(6):1867-1883

The oldest Asian record of alpheid shrimps, assigned to genus Alpheus, based on snapping claw fingertips from the Miocene Khari Nadi Formation in the Kutch Basin, western India reported herein, extends the fossil record of the family Alpheidae from Asia by ~22 million years. An early Miocene (Aquitanian) age is estimated based on the associated assemblage of calcareous nannofossils, Sphenolithus disbelemnos, Cyclicargolithus floridanus, and Reticulofenestra haqii. The co-occurring microbiota includes bony fish otolith remains, identified as “genus Gobiidarum”, isolated teeth of Dasyatis rays, Sphyrna sharks, and teleosts, ctenoid and placoid scales, ostracods, belonging to the genera Paractinocythereis, Alocopocythere, Ruggieria? Aglaiocypris, Bairdoppilata, and echinoid spines. Taken together, the microfossil assemblage and data from chemical analyses using Energy Dispersive Spectroscopy, X-Ray Diffraction and Wavelength Dispersive X-Ray Fluorescence of host and associated lithologies suggests prevalence of a shallow (neritic) to coastal marine (intertidal) depositional paleoenvironment.  相似文献   

Daily rainfall statistics of TRMM and CMORPH: A case for trans-boundary Gandak River basin     

BRIJESH KUMAR  KANHU CHARAN PATRA  VENKAT LAKSHMI 《Journal of Earth System Science》2016,125(5):919-934

Satellite precipitation products offer an opportunity to evaluate extreme events (flood and drought) for areas where rainfall data are not available or rain gauge stations are sparse. In this study, daily precipitation amount and frequency of TRMM 3B42V.7 and CMORPH products have been validated against daily rain gauge precipitation for the monsoon months (June–September or JJAS) from 2005–2010 in the trans-boundary Gandak River basin. The analysis shows that the both TRMM and CMORPH can detect rain and no-rain events, but they fail to capture the intensity of rainfall.  相似文献   

A fuzzy c-means approach regionalization for analysis of meteorological drought homogeneous regions in western India   总被引：1，自引：0，他引：1  

Manish Kumar Goyal  Ashutosh Sharma 《Natural Hazards》2016,84(3):1831-1847

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Prediction of flow rate of karstic springs using support vector machines     

Manish Kumar Goyal  Ashutosh Sharma 《水文科学杂志》2017,62(13):2175-2186

Complex void space structure and flow patterns in karstic aquifers render behaviour prediction of karstic springs difficult. Four support vector regression-based models are proposed to predict flow rates from two adjacent karstic springs in Greece (Mai Vryssi and Pera Vryssi). Having no accurate estimates of the groundwater flow pattern, we used four kernels: linear, polynomial, Gaussian radial basis function and exponential radial basis function (ERBF). The data used for training and testing included daily and mean monthly precipitation, and spring flow rates. The support vector machine (SVM) performance depends on hyper-parameters, which were optimized using a grid search approach. Model performance was evaluated using root mean square error and correlation coefficient. Polynomial kernel performed better for Mai Vryssi and the ERBF for Pera Vryssi. All models except one performed better for Pera Vryssi. Our models performed better than generalized regression neural network, radial basis function neural network and ARIMA models.  相似文献   

Genome Wide Computational Identification of Tuna (<Emphasis Type="Italic">Thunnus orientalis</Emphasis>) MicroRNAs and Their Targets     

Sangita?Chowdhury?Paul  Ashutosh?Sharma  Richa?Mehta  Sujay?PaulEmail author 《Ocean Science Journal》2018,53(4):727-734

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