Normalization of Hamiltonian in the Generalized Photogravitational Restricted Three Body Problem with Poynting–Robertson Drag     

B. S. Kushvah  J. P. Sharma  B. Ishwar 《Earth, Moon, and Planets》2007,101(1-2):55-64

We have performed normalization of Hamiltonian in the generalized photogravitational restricted three body problem with Poynting–Robertson drag. In this problem we have taken bigger primary as source of radiation and smaller primary as an oblate spheroid. Whittaker’s method is used to transform the second order part of the Hamiltonian into the normal form.   相似文献   

Global Optimisation of Time Domain Electromagnetic Data Using Very Fast Simulated Annealing   总被引：1，自引：0，他引：1  

S. P. Sharma  P. Kaikkonen 《Pure and Applied Geophysics》1999,155(1):149-168

--Efficacy of the global optimisation technique is demonstrated in the inversion of time domain electromagnetic data. Transient EM responses observed using a coincident loops system along several profiles and different time channels over a plate like conducting body are inverted, using very fast simulated annealing (VFSA) as an optimisation tool. Three time channels for each profile are considered in the inversion. Study reveals that only one run of global inversion considering a single multi-channel profile is not enough to resolve all the nine model parameters of a plate-like conducting body. However, the global inversion of a single multi-channel profile with several runs yields a mean model that is quite close to the true model. Considering many profiles and time channels together in the global inversion can yield reliable estimates of all the parameters. Computationally, this is not an efficient procedure. Analysis of the results shows, however, that two distant profiles are enough to yield all the model parameters reliably, even after one run of the global inversion. Both noise-free and noisy synthetic data are used in the inversion. Finally, field data are also inverted to study the performance of the global inversion.  相似文献   

Copper mineralization around the Ahar batholith, north of Ahar (NW Iran): Evidence for fluid evolution and the origin of the skarn ore deposit     

Habib Mollai  Rajesh Sharma  Georgia Pe-Piper 《Ore Geology Reviews》2009,35(3-4):401-414

This investigation presents and interprets fluid inclusion data from different lithological units of the Cu skarn deposits at Mazraeh, north of Ahar, Azarbaijan, NW Iran. The results provide an assessment of the P–T conditions and mineral–fluid evolution and suggest new exploration parameters. Five types of inclusions are recognized from quartz and garnet. The temperature of homogenization of Type I inclusions with daughter minerals halite and sylvite ranges from 312° to 470 °C with total salinity of 52 to 63 wt.% NaCl equiv.; Type II and III inclusions with halite have homogenization temperatures of 230° to 520 °C and salinity of 31 to 50 wt.% NaCl equiv. The salinity of Types IV and V biphase (liquid + vapor) inclusions, based on their final ice melting temperature, varies between 10.2 to 20.8 wt.% NaCl equiv. T_h vs. salinity plots of inclusions show that the salinity of the fluids correlates positively with temperature. The inclusions formed at low pressure. Changes in the temperature and salinity of the fluids can be reconstructed from the inclusions. Highly saline, high-temperature fluids were most abundant during the main chalcopyrite ore-forming phase in the skarn and mineralized quartz veins. Low-salinity aqueous fluids were abundant in barren veins, in which there is no evidence for early hot high-salinity brine, and might have resulted from late-stage dilution and mixing of hydrothermal fluids with meteoric water. Based on petrographic features and fluid-inclusion data, early-stage magnetite deposition is related to boiling of fluid at temperatures of about 500 °C. At a later stage, boiling at temperatures of around 320° to 400 °C favored the deposition of sulfides and Fe mobility was decreased at these lower temperatures. The following inclusion characteristics may be used as exploration parameters in the Mazraeh area. (i) Presence of high-temperature, salt-bearing inclusions, with T_h between 300 and 500 °C; (ii) High-salinity fluid inclusions; and (iii) Inclusions showing evidence of boiling of the fluid. In addition, the presence of magnetite is an important exploration parameter.  相似文献   

Taxonomy and affinity of Early Mesoproterozoic megascopic helically coiled and related fossils from the Rohtas Formation, the Vindhyan Supergroup, India     

Mukund Sharma  Yogmaya Shukla   《Precambrian Research》2009,173(1-4):105

A well preserved assemblage of compressed, straight, circular to sinuously coiled megascopic and helical carbonaceous fossils and other varied megascopic morphoforms are known from the Early Mesoproterozoic Rohtas Formation, Semri Group within Vindhyan Supergroup exposed in Katni district of central India. These megascopic remains are preserved as impressions, compressions, partially mineralized remains, and/or epi-relief. Some of the forms are typical filamentous empty sheaths and others are trichomes, with cell like entities under various stages of degradation. This study, based on fresh collections and also of the topotype material of the helically coiled megascopic fossils, straight forms and related fossilized remains occurring as epi-relief from Katni indicate that the two morphotaxa are distinct entities and possibly appear to be prokaryotes. Grypania spiralis and Katnia singhii are most likely of cyanobacterial origin. Spirally coiled and circular fossils, with epi-relief, and which probably represents a tissue grade organism, are considered as Spiroichnus beerii Mathur, 1983. Linear sheet-like carbonaceous solitary form has been placed in the morphotaxon Proterotainia and described as P. katniensis n. sp. Certain rare circular, carbonaceous forms are considered as Chuaria sp. A few circular disc-like forms found in the assemblage are treated as dubiofossils.  相似文献   

Tectonics and thermal structure of western Satpura,India     

D.M. Mall  S.R. Sharma 《Journal of Asian Earth Sciences》2009,34(3):450-457

Increased seismicity and occurrences of hot springs having surface temperature of 36–58 °C are observed in the central part of India (74–81° E, 20–25° N), where the NE trending Middle Proterozoic Aravalli Mobile Belt meets the ENE trending Satpura Mobile Belt. Earlier Deep Seismic Sounding (DSS) studies along Thuadara-Sendhwa-Sindad profile in the area has showed Mesozoic Sediments up to around 4 km depth covered by Deccan Trap and the Moho depth with a boundary velocity (P_n) of 8.2 km/s. In the present study, surface heat flow of 48 ± 4 mW m^?2 has been estimated based on P_n velocity, which agrees with the value of heat flow of 52 ± 4 mW m^?2 based on Curie point isotherms estimates. The calculated temperature-depth profile shows temperature of 80–120 °C at the basement, which is equivalent to oil window temperature in Mesozoic sediments and around 570–635 °C at Moho depth of 38–43 km and the thermal lithosphere is about 110 km thick, which is comparatively higher than those of adjoining regions. The present study reveals the brittle–ductile transition zone at 14–41 km depth (temperature around 250–600 °C) where earthquake nucleation takes place.  相似文献   

Slope stability assessment and design of remedial measures for Tungnath Temple at Uttarakhand,India: a case study     

Samanta  M.  Punetha  P.  Sarkar  S.  Dwivedi  A.  Sharma  M. 《Natural Hazards》2019,96(1):225-246

Natural Hazards - The present paper assesses the slope stability of the Tungnath Temple at Rudraprayag District, in the Indian state of Uttarakhand, and suggests the remedial measures. The...  相似文献   

Propagation of harmonic plane waves in a general anisotropic porous solid     

M. D. Sharma 《Geophysical Journal International》2008,172(3):982-994

Wave propagation is studied in a general anisotropic poroelastic solid. The presence of dissipation due to fluid-viscosity as well as hydraulic anisotropy of pore permeability are also considered. Biot's theory is used to derive a system of modified Christoffel equations for the propagation of plane harmonic waves in porous media. A non-trivial solution of this system is ensured by a determinantal equation. This equation is separated into two different polynomial equations. One is the quartic equation whose roots represent the complex velocities of four attenuating waves in the medium. The other is a eighth-degree polynomial whose roots represent the vertical slowness values for the four waves propagating upward and downward in a finite porous medium. Procedure is explained to associate the numerically obtained roots with the waves propagating in the medium. The slowness surfaces of waves reflected at the boundary of the medium are computed for a realistic numerical model. The behaviours of phase velocity surfaces are analysed with the help of numerical examples.  相似文献   

Selection of Test and Reference Areas for the Indian Deepsea Environment Experiment (INDEX)     

Rahul Sharma  B. Nagender Nath 《Marine Georesources & Geotechnology》2000,18(3):177-187

The Indian Deepsea Environment Experiment (INDEX) was conducted in the Central Indian Ocean Basin, to assess the effects of a simulated disturbance on the marine ecosystem and to collect data to predict the effects of large-scale mining. To select the Test and Reference areas for benthic disturbance, detailed studies were carried out for a better understanding of the topgraphic undulations and nodule distribution in five preselected areas of 10 ×10 nautical miles each. Flat topography was one of the important considerations for selection of the areas, because this would allow further dispersion of sediment plume and offer easier maneuverability of the benthic disturber. Relatively low nodule abundances were also preferred, to prevent clogging of the suction device used for resuspension of sediment. On the basis of morphological analysis and nodule distribution, two areas, T1 and A1, were selected as the best suited pair for the disturbance and monitoring experiment.  相似文献   

Long-range transport of aerosols from agriculture crop residue burning in Indo-Gangetic Plains—A study using LIDAR,ground measurements and satellite data     

K.V.S. Badarinath  Shailesh Kumar Kharol  Anu Rani Sharma 《Journal of Atmospheric and Solar》2009,71(1):112-120

Agriculture crop residue burning in tropics is an important source of atmospheric aerosols and monitoring their long-range transport is an important element in climate change studies. Synchronous measurements using micro-pulsed lidar, MICROTOPS-II sun photometer, multi-filter rotating shadow band radiometer (MFRSR) on aerosol optical depth and ground reaching solar irradiance were carried at an urban location in central region of India. Aerosol backscatter profiles obtained from micro-pulse lidar showed elevated aerosol layers up to ～3 km on certain days during October 2007. Satellite data observations on aerosol properties suggested transport of particles from agriculture crop residue burning in Indo-Gangetic Plains over large regions. Radiative forcing of aerosols estimated from SBDART model with input information on aerosol chemical properties, aerosol optical depth and single scattering albedo and broadband solar irradiance measurements using MFRSR showed good correlation (R=0.98).  相似文献   

Stable isotope systematics of surface water bodies in the Himalayan and Trans-Himalayan (Kashmir) region     

Kanchan Pande  J. T. Padia  R. Ramesh  K. K. Sharma 《Journal of Earth System Science》2000,109(1):109-115

Stable hydrogen (δD) and oxygen (δ¹⁸O) isotope ratios of the headwaters of the Indus and its tributaries, surface ice in glaciers, saline and fresh water lakes and thermal springs in the Himalayan and Trans-Himalayan (Kashmir) region are reported. The δ5D-δ¹⁸ relationship for the river samples shows a slope of 9.12 +-0.29 which agrees well with the estimate of 8.99 ±0.33 based on a simple Rayleigh fractionation model. The unique signature of a higher deuterium excess (d) of the ‘Western Disturbance’ is preserved in these samples. An altitude effect of -0.9 per mil/km is observed in the δ¹⁸O of Indus waters. At a lower altitude (Beas) the altitude effect is almost double, indicating that the altitude effect decreases with elevation in this region.  相似文献